Elderhorst's Manual of Qualitative Blow-pipe Analysis: And Determinative Mineralogy

William Elderhorst · 1873 · Historical

Elderhorst's Manual of Qualitative Blow-pipe Analysis: And Determinative Mineralogy by William Elderhorst (1873). Full text and reference in the Mountain Man…

Public-domain full text preserved in the Mountain Man Mining Library. Original source: archive.org.

at |: .com/I

.,t.db,

Table Of Spectra According To Kirchoff & Bunsen.

Ho.led by

ELDERHORSTfS MANUAL

Qualitative

Blow-Pipe Analysis,

Determinative Mineralogy.

EDITED BY HENRY B. NASON, Ph. D.,

And

CHARLES F. CHANDLER, Ph.D.,

xSiitian, Jcuiaed and jfnhirgcd.

Philadelphia:

Porter & Coaxes,

No. S22 Chestnut .

Ho.led by

EoKKd, acOL>rdLng to Act of CoiiB;res$T in the year 1873, by T. ELLWOOD ZELL,

H.,t.db,

Preface

Fourth Edition.

THE editors have made a. complete revision of this fourth edition of Elderhorst's Manual. While many alterations and additions have been made, both in methods of determination and mineral species, they have endeavored not to make the book loo large, or destroy its original plan.

The names of minerals and ores, and, in many cases, the formulae have been made to agree with those given in the last edition of Dana's Mineralogy.

The few pages on the spectroscope aUd Bunsen's flame reactions, it is thought, will be found useful and convenient for the student.

It is hoped this edition will meet with the same favor, and will be found as valuable a guide, as those which have preceded it.

H. B, N. C. F. C.

o.led by

Preface To The Third Edition.

THE present edition of this " Manual " is like the preceding, designed to serve as a text boot in the nistiuction in Blow-pipe Analysis and Determinative Mineralogy, in the Rensselaer Poly- technic Institute.

In the first thiee chapters, but few alterations and additions have been made. The fourth chapter has leen i-onsiderably enlarged by increasing the number of species, in the itlection of which I have paid particular regard to those occurring in the American Continent ; for this reason, many less important ores have found a place in the list to the exclusion of others, which, though more valuable, have no! hitherto tieen fomid in America.

The lifib chapter, containing a systematic method for (he discrimi- nation of inoianic compounds, is a translation, but slightly altered, of the "ZVjWb dickotoTique prrur -reconnaltre tssminiraux" aa given in Laurent's "Analyaeau Ckalumeau." It is of no great value to the experienced analyst, but very useful for beginners, and it is on their account that I have given it a place in the Manual.

The sixth chapter is not contained in the first edition. It is hardly necessary to allege any reason for its introduction into this edition. The admirable method of Professor von Kobell for the discrimination of minerals is, almost beyond dispute, the most practical and most reliable that has ever been published. The sixth chapter is nothing but an extract from Prof. v. Kobell's treatise on tliis subiect.

For Che material of this compilation, the author is principally indebted to the works of Plattner, Berzelins, Von Kobell, Dana, and Mitchell.

The author, finally, begs to tender Ws thanks to his friend, Professor Chandler, of Union College, for the valuable sueitions he has re- ceived at his hands, and which he has acted upon to the best of his ability, being fully convinced that by adding the improvements re- commended by his friend, the practical utility of this little Manual will be greatly increased.

William Elderhorst,

o.led by

Introduction.

IN preparing this little Manual, it has been my principal care to adapt it to the use of tlie beginner. The use of the blow-pipe, though elaborately studied and extensively writ- ten on by some of the first chemists and mineralogists of the preceding and the present century, has not yet been duly appreciated. This neglect is, perhaps, owing to the rapid ad- vancement of cheniical analysis in the humid way, which furnishes, on the whole, more reliable results, and allows of an easy quantitative determination of the various constituents of a body. But it was overlooked that this mode of analysis absorbs much more time, and requires the use of an extensive set of apparatus, whereas an examination before the blow-pipe is sooner performed ; requiring scarcely as many hom-s as an examination in the humid way requires days, and that with the aid only of a few reagents and instruments of small size. It is for this reason that a knowledge of blow-pipe operations is less valuable for the Chemist by profession than for the Mining Engineer, the Mineralogist, and the Geologist, A small port- able box will hold all the necessary reagents and instruments, so that he may carry them with him on his expeditions and travels, and examine on the spot the lliiflerals which he meets with on his explorations ; an advantage which ought, tiuly, not to be overlooked.

For teachers who have not hitherto devoted much time to instrucdon in this department, a short exposition of tlie course which I have followed for a number of years may, perhaps, be desirable. For elementary instruction, the students are only furnished with the principal reagents, viz. ; carbonate of soda,

o.led by

Vi Introduction.

salt of phosphoms, borax, and solution of cobalt ; of apparatus theywant afluid-lamp, blow-pipe with platinum point, platinum- pointed forceps, platinum wire, charcoal, and closed and open glass tubes. After having explained to them the action of the two cones of the flame, aud instructed them in making beads, and conducting tbe processes of oxidation and reduction, I make them perform the most important operations," and study the behavior of the most commonly occurring substances, with and without fluxes. I give the substances in somewhat the following order ;

SesquioKide of iron, all the reactions given in Table il, 13.

Einoxide of manganese, Table II, 16.

Sesquioxide of chromium. Table II, 6.

Oxide of cobalt, and nickel, Table H, 7, 19.

Protoxide of copper. Table II, 8, and 37.

Oxide of sine. Table II, 35, and metallic zinc, 35, 45,

Oxide of tin. Table !I, 30, and metallic lin, 26.

Oxide of lead. Table II, 15, and metallic lead, I 23.

Oxideof bismuth. Table li, 3, and metallic bismuth, ?? 17, Z2.

Antimonousoxide.Table II, l,andmetallic antimony, Jl 16,21,

Arseno us oxide, Table II, 2, W 9, 15.

Oxide of mercury, Table II, 17.

Alumina, Table I, 5, and 44.

Magnesia, Table I, 4, and 44.

Silica, I 39.

A sulphide, 10, 14, 107.

A borate, 60.

A chloride, 65, 66.

Having performed all these operations, the student will be qualified to enter upon the analysis of substances of not too compound a character. If he meets on his way with bodies, thebehavior of which before the blow-pipe he has not pre- viously studied, he will not have any difficulty in determining their character if he follows the directions given in the second chapter. The modiis operandi yiiH be best understood by a few

I. The substance under exn.mi nation is sulphide of antimony.

.,t.db,

INTRODUCTION. Vll

Examination in a matrass : At a very high temperature, a hlack sublimate is oblaitied, becoming reddish-brown when cold. In reading over the list in lo, we find this character belonging to sulphide of antimony.

Examination in an open glass tube : Gives sulphurous acid detected by the odor and action on blue litmus paper, and white fumes which partly condense in die tube. On examining the sublimate with a magnifying glass, it is found to be amor- phous, hence must be antimonous acid (J l6).

Examination on charcoal alone : Is completely volatilized with emission of sulphurous acid, and deposits a white vola- tile coating, possessing the properties of the coating of anti- mony (?2l).

These few operations are quite sufficient to establish the nature of the substance under trial, since the absence of the more fixed metals is proved by the volatility of the substance on charcoal and in the open tube, and the absence of metals giving coatings by the purity of the antimony-coating. The presence of arsenic would have been betrayed by an alliaceous odor when heated on charcoal. The only substance which would have escaped detection by these operations is sulphide of mercury. In order to ascertain its presence or absence, we perform the operation given under " Mercury " in Chap. III.

The result giving an answer in the negative, the body was "sulphide of antimony,"

2. The substance under examination is chromate of lead.

Examination in a matrass ; 1 Fuses and changes color, but

Examination in an open tube : f gives nothing volatile.

Examination on charcoal alone ; Fuses, gives small metallic globules, and deposits a coating which is lemon-yellow while hot, and sulphur-yellow when cold, indicative of lead 23). It is always desirable to collect the metal to a large globule, and to study its physical properties. This end is best attained by mixing the substance with carbonate of soda and a little borax, and exposing the mixture to the reduction flame on charcoal, in this particular- case, a metallic button is obtained

o.led by

INTRODUCTIOtT.

whicli is soft, may be flattened by the hammer and cut by the knife, properties belonging to metallic lead.

Examination with borax and salt of phosphorus ; Before pro- ceeding with this examination it is necessary to test the sub- stance for the presence of sulphur after the method given 107 (unless the presence of this element was detected by the exami- nation in the open glass tube or on charcoal alone) ; no sulphur being present, borax and salt of phosphorus beads are made on charcoal, and small portions of the substance added. With both fluxes nearly the same reactions are obtained ; in oxida- tion flame dark-red while hot, and fine yellowish -green when cold ; in reduction flame green, hot and cold. In order to find out what body produces such reactions, we use Table III, which leads us to sesquioxide of chromium. To corroborate the re- sult, the substance may be fused with carbonate of soda and nitre, as described 68.

The physical properties of the body under trial lead to the final conclusion that it must be chromate of lead.

3. The substance is an alloy of silver, copper, and lead.

Examination in a matrass : 1 ,t t

, , . , rJo change.

Exammation m an open tube : )

Examination on charcoal alone ; Fuses and deposits a copious coating, which is lemon-yellow while hot and sulphur-yellow when cold, indicative of lead 23) ; the coating cannot contain any oxide of bismuth, because the color would be darker in this case, but might contain oxide of zinc or oxide of antimony. The test is for the presence of the foiiner, the coating is played upon with the oxidation flame : it is completely volatile, hence no zinc present (might also be tested with solution of cobalt, 1 45) ; to test the coating for the presence of oxide of antimony, it is scraped ofi" from the charcoal and dissolved in a bead of salt of phosphorus, v. 87, or the alloy is treated with boracic acid as described under the head of "Antimony " in Chapter III. If the blast is continued for a loag time, a faint dark-red coating is formed near the assay-piece, indicative of silver, J 27, and a dark metallic globule rt

o.led by

Introduction. Ix

Examination with borax and salt of phosphorus : The globule remaining on the charcoal after volatilization of tlie lead, is treated with borax on charcoal in oxidation flame ; the borax becomes colored. Owing to the reducingeflect of the charcoal, the influence of the oxidation flame cannot be well observed on charcoal, hence the borax is removed from the metaUic globule, fastened into the hook of a platina wire, and here exposed to the action of the oxidation flame ; the bead is green while hot, and blue when cold. On consulting Table III we find that this reaction is produced by oxide of copper, and by a mixture of oxide of cobalt and sesqiiioxide of iroa : to decide between the two, we now expose the bead to the action of the reduction flame ; it becomes red and opaque, thus proving the presence of oxide of copper.

By the examination on charcoal, /er jc, we were led to sus- pect the presence of silver ; in order to establish this beyond a doubt, we refer to Chapter III, "Silver; "here we find a method los) by which the presence of silver may be ascertained in compounds of all descriptions. In our case, having to deal only with lead, copper, and silver, the treatment with vitrified ijoracic acid and metallic lead is, of course, superfluous. We place our alloy at once on the cupel and direct the oxidation flame upon it; if, after cessation of the rotatory motion, the globule should not possess the bright lustre of silver, some pure metallic ISad has to be added, in order to remove the last traces of copper. We finally obtaia a bright globule exhibiting all the characteristic properties of silver.

Thus we have established the presence of lead, copper, and

4. The substance under examination is copper nicliel, con- taining arsenic, sulphur, ttickel, cobalt, and iron.

Examination in a matrass ; GiVes a sublimate, consist- ing of octahedral crystals, pointing to the presence of arsenic

Examination in a glass tube open at both ends : Gives a co- pious crystalline subiimate of arsenous acid, and a faint odor of sulphurous acid ; to establish the presence of sulphur beyond

H.,t.db,

X. Introduction.

doubt, we refer to Chapter III, " Sulphur," where we find the method (I 107) for discovering sulphur when in combination with other substances. In performing the test there described, we obtain the sulphur reaction.

Exaroination on charcoal alone : Gives abundant arsenical fumes, leaving a metallic globule which, even with continued blowing, does not give rise to the formation of a coating on the charcoal (absence of volatile metak).

Having removed all volatile substances, we now proceed to examine the remaining globule. On applying a magnet, we find it powerfully attracted, showing the presence of either iron, nickel, or cobalt, perhaps all of them, either alone or com- bined with other non-volatile metals. We add some borax to the globule and expose it to the action of the oxidation flame, then remove the borax from the globule, fasten it into the hook of a platinum wire, atid here observe the color : green while hot, blue when cold as in the preceding case (example 3), but on exposing the bead to the action of the reduction fla.me [which is best done by placing it on charcoal and touching it with tin) it does not become brown and opaque, showing therefore the presence of a small quantity of iron with cobalt. We now add a fresh portion of borax to the metallic globule, in order to see whether it consists entirely of cobalt (that it cannot contain any considerable amount of iron, is proved by the appearance of the cobalt reaction in the first trial, iron being much more readily dissolved by borax than cobalt) : the bead is violet while hot, and assumes a brownish color on cooling ; by refer- ring to Table III, we see that this effect is produced by nickel containing cobalt. Referring to Chapter II!, "Nickel," we find the method to detect the presence of this metal when in com- bination with iron and cobalt, and also the presence of copper, if the assay should contain a small quantity of it.

By the above examples, the use of the methods given in the third chapter will be sufficiently illustrated. If the substance under examination is of a simple composition, its nature is readily ascertained by following the general method laid down in the second chapter ; but if the reactions obtained clearly

.,t.db,

INTRODUCTION. xi

point to the complex nature of the body, we refer to the respec- tive sections of Chapter III ; if, for example, we suspect the presence of cobalt in a mineral consisting of arsenides, we test tlie substance according to 69 ; if a smalt quantity of copper is to be discovered in a mineral, we proceed as directed in ? 71, etc.

The student who is willing to devote more time to the sub- ject than is usually allotted to it in our colleges, will do well to go carefully tlirough all the reactions given in the second chap- ter, and thus familiarize himself with the colors and other properties of the various coatings, sublimates, etc., and also to perform the principal testa by which substances are discovered

when in combination with others, which are fully given in the third chapter. In order to obtain characteristic reactions, it is important to experiment upon a suitable substance. For the benefit of the beginner, who would naturally be embarrassed in the choice of a body suitable for the experiment, I add a list of substances which, with few exceptions, are readily ob- tained, and which are sulScient to illustrate all the important reactions. After having mentioned a reaction, or described a process (in Chapters II and III), I have added a number in [ ] brackets. The number points to the substance of the list, given on p. xii, best adapted to illustrate the reaction. As each experiment requires only a very small quantity of tlie sub- stance, they are most conveniently kept in small glass tubes of about an inch and a half in length and one-eighth of an inch in diameter. For the first fourteen substances no glass tubes are required, since they are the regular blow-pipe reagents. A small box containing seventy-five of the little tubes will hold the whole collection.

W. E.

o.led by

COLLECTION OF SUBSTANCES, Well adapted to IllnstrBte tlie Important Keactlons of BodioB bofoiB the

J. Iodide of potassium i. Chloride of sodium, ride of ammoni

i. Suiphate of copper. .te of lead. e afmtimooy.

i. Oxide of bismuth. 7. Oidde of cadmium, i. Sesiuioitida of e

]e of mercliry. 58.

Jloy of lead and an

N CobaHiIe

Hoy of lead and b

IS So Realgar

.

61 Qnnabar

Hoy of lead and di,

8' Nceoble

Hoy of lead, copp

f 33 Molybde

and silver.

64 Berthien

S3 Sulphides of a

Ho.led by

Table Of Contents.

Introduction v

List ok Substances serving to Illustrate the Reactions., xii

CHAPTER I. Auxiliary Apparatus AND Reagents 17-24

Chapter Ii.

General Routine of Blow-pipe Analysis 25-46

Examination in a Closed Glass Tube 28

" IN A Glass Tube Open AT Both Ends 32

" ON Charcoai., /e?-je 34

" IN THE Platinum-pointed Pincers 37

" WITH Borax and Salt of Phosphoros 41

" WITH Carbonate OF Soda 42

" WITH Solution ofCoisalt 44

CHAPTER III. Special Reactions for the Detection op Cer- tain Substances when in Combination with

Others 47-84

Ammonia 48

Antimony 48

Arsenic. 50

Bismuth 53

BoHflcic Acid 54

Bromine 55

Cadmium 55

Chlorine 56

Chromium 56

Cobalt 58

CoiTEK , 59

.,t.db,

Contents.

Fluorine. 6i

Gold 62

Iodine 63

Iron 64

Lead 66

LiTHiA 68

Manganese 69

Mercuey 69

Nickel 70

Nitric Acid 70

Phosphoric Acid 71

POTASSA 7a

Selenium 73

Silica 74

Silver 75

Sulphur 77

Sulphuric AND Sulpiiuroxts Acids 78

Tellurium 79

Uranium 82

Zinc 83

Chapter Iv.

Characteristics of the most Important Ores ; THEIR Behavior before the Blow-hi'E, and TO Solvents 85-130

Ores of Antimony 86

" Arsenic 88

" Bismuth 89

" Chromium 91

" Cobalt 92

" Copper. 94

" Gold, Platinum, and laiMUM loi

" Iron 102

" Lead 107

" Manuakese 114

o.led by

Contents.

" Silvia 120

" Tin 124

V Zi\(- 1 25

APPENDIX —Fossil J-ut,L (.ARiiONAiLjis (. us'lund!, 128

CHAPTER V. Systematic Method for the Determination

OF Inorganic Compounds 131-145

CHAPTER VI. On the Determination of Minerals by Means OF THE Blow-pipe, aided by Humid Analy- sis 146-209

Chapter Vii.

Colored Flames, Flame Reactions, and Spec- trum Analysis.. 210-259

Tables.

TABLE I. — Behavior of the Alkaline Earths and the Earths Proper before THE Blow-pipe 262-267

TABLE II. — Behavior of the Metallic Ox- ides BEFORE THE BlOW-PIPE 268-287

TABLE III. — The Metallic Oxides Arranged WITH Reference to the Colors which THEY Impart to the Fluxes 288-295

APPENDIX. Jolly's Spring Balance ioe Determining the Specific Gravity of Minerals. — Test of the Fusibility of a Mineral 296-293

o.led by

Abbreviations.

O.Fl. for Oxidalion flame; R.Fl. for Reduclion flame; S.Ph. for

Salt of Phosphorus ; Bx. for Borax ; Sd. for Carbonate of Soda; So. Co.

for Solution of Nitrate of Cobalt; Ch. for Charcoal; Ct. for Coaling;

Blp. for Blow-pipe; H. for Hardness; G. for Specific Gravity.

.,t.db,

A Manual

Qualitative Blow-Pipe Analysis.

Chapter I.

Auxiliary Apparatus and Reagents.

§ I, The common blow-pipe of gas-fitters, jewellers, etc., is not very well adapted for analytical researches, as the narrow outlet becomes frequently obstructed by the moisture which is exhaled from the lungs and condenses in the tube. To avoid this inconvenience, the long cylin- drical tube, a b, of the blow-pipe should be furnished at the extremity with a globular or cylindrical chamber, c d, for the reception of the condensed water. In this chamber the jet, f g, is inserted at a right angle to the tube. Silver is, in many respects, the best material for the construction of a blow-pipe, but has the disadvantage of becoming very hot when used for a long while, so that it becomes almost impossible to hold it with the naked fingers ; next to silver stands German silver and brass. For jets, h, platinum is preferable to all other metals. A mouth-piece, a, of box-wood, horn or ivory is convenient, though not necessary. (Fig. i.)

o.led by

r8 AUXILIARY APPARATUS AND REAGENTS.

I a. Any kind of flame may be used for the blow-pipe, provided it be not too small. Some of the older chemists ubed common candles in preference and it must be ton fessed that, in the majority of cases, the heat piodiiced by the flame of a good sperm candle is quite sutfiuent Ber/elms recommended an oil lamp with i flit uick which lb now in general use as " Lerzelms s Blow pipe Lamp."* A common fluid (mixiuic of tw-Ue part&

of alcohol and one of turpentine, or four parts of alcohol and one of benzine) lamp, with a rather large burner, answers every purpose ; it gives a very good heat, and, besides being much cleaner than an oil Samp, admits of a very quick and accurate adjustment of the size of Refined rapeseed or olive oil should be used in Ihis lamp.

.,t.db,

Auxiliary Apparatus And Reagents. I9

the flame, by means of a little brass cylinder, which is movable, and slides up and down the burner. Illuminat- ing gas, however, is most convenient for blow-pipe experi- ments, and the Bimsen burners best suited for the purpose. (Fig. 2.) The burner rests on a foot, a i, into which a block, c d, is screwed. To this is attached the tube, e f, in which the gas coming through k, mixes with the air drawn, through the holes in c d, and burns at f with an almost non-luminous flame.

For blow-pipe purposes, the lube g h, flattened at the top and slanted, is introduced, through which the gas passes without being mixed with the air, and bums with its usual luminous flame. The heating of substances in glass tubes and matrasses is best performed over a common spirit lamp, or Bunsen gas-burner,

§ 3. As supports, charcoal, platinum, and glass are principally used. Wood charcoal is in most cases the best support. It must be well burnt, and not scintillate or smoke ; it must leave but little ash ; charcoal of light wood, as alder and pine, has been found the best. Only those sides which show the rings of growth should be used.

Platinum is used whenever the reducing action of the charcoal acts injuriously. It is advantageously employed on all occasions where no reduction to the metallic state takes place, since the color of the flux is much better seen on the platinum than on charcoal. It is mostly used in the shape of wire, the end of which la bent so as to form a hook, which serves as support to the flux (Fig 3.) As foil, its use is very limited. A small platmum spoon or capsule, of from about 1 2 to 15 m m m diameter, is very convenient for fusing substances with bisulphate of potassa or nitre. (Fig. 4.)

Glass tubes, open at both ends, are used for calci

o.led by

20 Auxiliary Apparatus And Reagents.

and for testing the presence of subsfances which are volatile at a high temperature. The tubes should be from 4 to 6 inches long. Of glass tubes, sealed at one end, or little matrasses, an assortment should always be kept on hand, since they are of very frequent use. (See Figs. 14, 15, 16, 17.)

§ 4, Of other apparatus, the most necessary arc:

A mortar of agate or chalcedony, from one and a half to two inches in width, with pestle of the same material. (Fig. 5.)

fig. 3.

Forceps of brass or German silver, with platinum points.

Forceps of steel.

A small hammer and anvil, both of sCeel and well pol- ished.

A three-cornered file for cutting glass tubes, trying the hardness of minerals, etc.

A small magnet.

A pocket magnify ing-gl ass.

Coal-borers. (Figs. 6, 7, 8.)

o.led by

A UXILIAR y APPASA TUS AND REA GENTS. 2 1

Cobalt glass and a prism with indigo solution. (Fig. 9.) This prism is made

of plate glass, and filled with a solution prepared by dissolving 1: pait of indigo in 8 parts of fun ing sulphuric acid add

mg 150.

water and filtering practice the prism is held close to the eje and moved horizontally, so as to allow the light of the colored flame to reach the eye through succes sively thicker portions of the absorbing medmrr A set of watch-glasse; the reception of the

, which -piece, the 1

very convenient for itallic globules, etc.

fig. 9.

§ 5. Of reagents, Carbonate of Soda, Borax, and Salt of Phosphorus, are the most important ones ; but there are others, which, though not so extensively used, still are indispensable for the detection of certain substances ; others, the use of which is very limited, are omitted in this list. All should be as pure as possible.

Carbonate of Soda ; The carbonsite or the bicar- bonate may be employed ; it must be perfectly free from

o.led by

22 Auxiliary Apparatus And Reagents.

sulphuric acid, for the presence of which it may be tested, as shown § 107.

The neutral oxalate of potassa and the commercial [fused] cyanide of potassium deserve in many cases the preference, their reducing powers being superior to that of carbonate of soda.

Borax; The commercial article is purified by recrys- tallization, the crystals washed with distilled water, dried, and reduced to a coarse powder.

Salt of Phosphorus [phosphate of soda and ammonia] : 100 parts of crystallized phosphate of soda and sixteen parts of chloride of ammonium are dissolved in thirty-two parts of water ; the solution is aided by heat, the liquid filtered while hot, and the crystals, which form on cool- ing, dried between blotting-paper. When pure it gives a glass which, on cooling, remains transparent ; if this is not the case it must be purified by recrystallization. Nitrate of Soda ; Serves only as an oxidizing agent. Bisulphate of Potassa ; It is employed in the fused [anhydrous] state as a coarse powder ; it must be Isept in a bottle provided with a ground-glass stopper.

Vitrified Eoracic Acid : It is employed in the state of a coarse powder.

Fluor-spar : Must be deprived of water by ignition ; must be perfectly free from boracic acid, which may be tested as described § 61. It is convenient to keep in a separate bottle a mixture of one part of finely-powdered fluor-spar with four and a half parts of bisulphate of potassa. Nitrate of Cobalt, in solution : It must be pure, free from alkali, sesquioxide of iron, and nickel. The solu- tion should not be too concentrated, and as only one or two drops are used at a time, it is convenient to keep it in a bottle provided with a long stopper or pipette, for the purpose of dropping. (Fig. 10.)

o.led by

Auxiliary Apparatus And Reagents. 23

Nitrate or Oxalate of Nickel It must be perfectly free from iron and cobalt; it is tested with borax, witli which it ought to produce a pure biovin glass Oxide of Copper : It is bes.t prepated by ignit jIUl iiig the dried nitrate in a porcelain dish

Chloride of Silver; It is piepared bj pretipi tating a solution of nitrate of silver with hydro A chloric acid, washing the precipitate, and making iffl it into a thick paste with water, which is kept m a small glass -stoppered bottle. This reagent should not be used with platinum wire, since the silver fuses with the platinum loan alloy; thin iron wire is in this case substituted for the platinum. For each experiment a fresh hook should be made.

Pure Metallic Lead : It is easily obtained pure by de- composing a solution of the acetate by metallic zinc ; the precipitate is repeatedly washed with water and then dried between blotting-paper.

Metallic Iron : In the shape of fine [pianoforte] wire.

Metallic Tin ; Usually in the shape of foil, which is cut into strips and rolled up tightly.

Bone-ash ; In the state of very fine powder for ciipella-

Test Paper : Blue and red Litmus Paper, and Brazil Wood Paper.

§ 6, If the analytical research is strictly confined to blow-pipe operations, the above enumerated reagents are sufficient; but if, as is sometimes advantageously done, some simple operations of the humid method of chemical analysis are called to aid, the list must be somewhat ex- tended. The most important of these reagents, all of which must be kept in bottles with ground glass stoppers, are: Sulphuric Acid, Hydrochloric Acid, Nitric Acid,

o.led by

24 Auxiliary Apparatus And Mbagents.

Oxalic Acid, Hydrate of Potassa, Ammonia, Carbonate of Ammonia, Chloride of Ammonium, Molybdate of Ammonia, Ferrocyanide of Potassium, Ferricyanide of Potassium, Bichloride of Platinum, Acetate of Lead, Sul- phuretted Hydrogen Water, Sulphide of Ammonium, Al- cohol, Distilled Water.

The principal auxiliary apparatus are : Test-tubes and Test-tube Rack, small Porcelain Dishes, small Beakei- Glasses, Glass Funnels, Filter Stand, Filter Paper, Plati- num Crucible, Glass Rods, Glass Plates for covering beakers, and either alcohol lamps or gas-burners.

o.led by

Chapter Ii.

Of the Flame, and General Routine of Blow-Pipe Analysis.

The Same of a candle consists of three distinct parts — the dark central zone or supply of unburnt gas aurroimd- ing the wick ; the luminous zone or area of incomplete combustion; and the non-luminous zone or area of com- plete combustion. (Fig. II.) In this outer zone the supply of oxygen is greatest, all the carbon is at once burnt, and the flame \h, comes non-luminous. The effect of produLuig a complete combustion at once throughtut the flame is seen in the Bunsen g-a, lamp, or burner. In this lamp (see Fig. z) the gis issues from a small central burner, md piss ing up the tube draws air with it through the holes at the bottom of the tube ; the mixtuie of air and gas can be lighted at the top of the tube, where it burns with a non luminous flame. If the holes be closed, the gis alone burns with the ordinary bright flame The blow-pipe flame may also be divided mto two distinct parts — the oxidizing flame, where there is excess of oxygen, and the reducing flame, where there is excess of carbon ; and these are distinguished by the same properties as the outer and inner zone of the candle flame.

Fg 11

o.led by

OF Tim FLAME, AND GENERAL

To produce the oxidizing flame (Fig. 12), the stream ot should not be too strong. The jet of the blow- pipe 16 placed juSt within the flame near the slit in the tube, so that a strong current of air is thoroughly mixed "mth the gas, which forms an inner long blue flame, a b. The hottest part of the flame is before the apex of this blue cone, d, where the combustion of the gases is most complete. For fusion, substances are exposed ti

pUt-ed a little beyond the

The ridui,ing flame (Fig 13) IS produced by so placi ig the blow pipe that the jet just reaches the flime a little aboe the slit, and the current of air made to pass a lit tie higher above the tube than in Fig 12 The whole flame now appears surrounded with a pale blue The most active part of the flame lies between a and d, somewhat nearer a. Any reducible metallic oMde placed at this point will be deox- idized or reduced, on ac- the free carbon in the flame to combine with the oxygen.

The current of air

should be produced with

the cheek muscles alone.

Fig, ]3, and not with the lungs.

as a long, luminous cone, a mantle, which extends to e

o.led by

Routine Of Blow-Pipe Analysis. 2/

The trumpet-shaped mouth-piece is pressed against the lips, and breathing is effected through the nostrils. In this way a constant and regular blast may be produced, and, after a little practice, without any perceptible exertion or weariness.

§ 7. On examining a substance before the blow-pipe, with a view to determine its nature, or to ascertain the presence or absence of certain matter, it is advisable to follow a systematic course, composed of a series of opera- tions, and to attentively observe the changes which the body undergoes under the influence of the various agents which are brought to act upon it. The various operations to which the assay is submitted are so many questions, to which the phenomena we observe constitute so many an- swers ; and from their appearance, or non-appearance, we are able to draw definite conclusions as to the nature of the substance under examination.

The following order, and the rules to be observed in the execution of the various operations, are essentially the same as first pointed out and laid down by Berzelius.

1. Examination in a glass tube, sealed at one end, or a matrass, which is a glass tube sealed at one end and blown into a bulb. (Figs. 14 and 15.)

2. Examination in a straight or slightly bent glass tube open at both ends. (Figs. i6and 17.)

3. Examination on charcoal by itself.

4. Examination in the platinum- pointed forceps, or on platinum wire by itself.

5. Examination with borax, and salt of phosphorus.

6. Examination with carbonate of soda.

7. Examination with solution of cobalt. Regarding the size of the assay, a piece the size of a

mustard seed will generally be found sufficient; larger

o.led by

2S Of The Flame, And General

pieces, without showing the reaction mire distinctly, re- quiring so much more labor. In mt cases however, it is advantageous to employ a greUer qiaility, ex. gr. in

Fig. 14, Fig 15 Fig 16 Fig 17

reductions, or in heiting in a gHss tube j tor the larger the metallic globule, and the greater the amrtrat of tho subli- mate produced, the more readily can its nature be ascer- tained.

It is a good plan to place the lamp on a large piece of white paper, so that if a globule or portion of the speci- men is dropped, it may be easily found.

Ezamination in a Closed Glass Tube, or a Matrass.

§ 8. The assay-piece is introduced into a small glass tube, sealed at one end, or into a small matrass, and heat applied by means of a gas or spirit lamp. The heat must

o.led by

ROUTINE OF BLOW-PIPE ANALYSIS. 2g

at first be very low, but may be gradually raised to red- ness, if necessary. By this treatment we learn ;

§ 9. I. Whether the substance is entirely or partly volatile or not.

Among the phenomena to be observed, the following are deserving of particular attention :

The substance gives out water, which partly escapes and partly condenses in the colder portion of the tube. This points to the presence of a salt containing water of crystallization* [No. 22], or to the presence of a hydrate, or to such salts which contain water mechanically inclosed between the laminse of the crystals [No. 18] ; in this case the body usually decrepitates. The drops of condensed water are to be examined with test-paper: an alkaline reaction denotes the presence of ammonia, and acid re- action the presence of some voladle acid, as sulphuric, nitric, hydrochloric, hydrofluoric acid, etc.

§ 10. The substance gives out a gas or vapor. Those of most usual occurrence are :

a. Oxygen, easily recognized by placing a small piece of coal upon the assay, which burns brilliantly on being heated; points to the presence of a peroxide, nitrate, chlorate, bromate or iodato [No, zo].

b. Sulphlirous Acid, easily recognized by its peculiar odor and action on blue litmus paper ; indicates the pres- ence of a sulphate or sulphite [No. 22].

f. Salphuretted Hydrogeu, recognized by its peculiar odor ; indicates the presence of sulphides containing water.

d. Nitrous Acid, or peroxide of nitrogen, recognized by its deep orange-red color and acid reaction ; indicates the presence of a nitrite or nitrate [No. 33].

The numbers refer to list of substances following ihe introduction.

o.led by

30 Of The Flame, And General

e. Carbonic Acid, recognized by causing a turbidity in a drop of lime-water suspended from a watch-crystal and exposed to the escaping gas ; points to the presence of a carbonate,

/. Cyanogen, recognized by its peculiar odor and by burning with a crimson flame ; indicates the presence of a cyanogen compound,

g. Ammonia, recogniced by its odor and alkaline re- action ; indicates the presence of an ammoniacal salt or of an organic nitrogenous substance; in the latter case, the mass usually blackens, and evolves at the same time either cyanogen or empyreumatic oils of oifensive odor [No. 3].

h. Hydrofluoric Acid changes the color of test-paper, and also attacks the glass just above the assay, and makes it dull.

i- Iodine is indicated by violet fumes and its peculiar odor.

§ II, The substance yields a sublimate. The subli- mate is either white or possessed of a peculiar color. White sublimates are formed by

a. Many Salts of Ammonia, — On removing the subli- mate from the tube, placing it on a watch-crystal, adding a drop of hydrate of potassa, and applying heat, ammonia is evolved [No. 19].

b. The Chlorides of Mercury. — The subchloride sub- limes without previous fusion; the protochloride fuses first, then sublimes; the sublimate is yellow while hot, but becomes white on cooling [Nos. 39 and 40]. Oxide of mercury forms globules of metallic mercury.

c. Oxide of Antimony. — It fuses first to a yellow liquid, then sublimes ; the sublimate consists of lustrous needle- shaped crystals [No. 24].

o.led by

Routine Of Blow-Pipe Analysis.

d. ArsenOUS Acid, — The sublimate consists of octahe- dral crystals [No. 25].

e. TellurOilS Acid. — Shows a reaction similar to Chat of oxide of antimony, but requires a much higher tempera- ture ; the sublimate is amorphous.

/. Osmio Acid— Forms a sublimate of white drops, with a pungent, disagreeable odor.

Sublimates possessed of metallic lustre, so-called metal- lic mirrors, are formed by :

a. Metallic Arsenio and Arsenides containing more than ooe equivalent of arsenic to two of metal ; also, some sulph -arsenides [No. 77]; cutting the tube below the sublimate, and exposing the mirror to gentle heat in the gas flame, the peculiar odor of arsenic is perceived,

b. Mercury Amalgams, and some salts of mercury ; the sublimate consists of minute globules of metallic mer- cury, which, by friction with a piece of copper wire, readily unite to larger globules [No. 47].

c. Some alloys of Cadmium.

d. Tellurium — Only at a very high temperature ; the sublimate consists of small globules, which solidify on cooling.

Sublimates possessed of distinct color are formed by :

a. Sulphur and Sulphides containing a large amount of sulphur ; the sublimate is from deep-yellow to brownish- red while hot, but pure sulphur- yellow when cold [No. 7S]-

b. The Sulphides of Antimony, alone or in combina- tion with other sulphides ; the sublimate forms only at a very high temperature, and is deposited at a short distance from the assay-piece ; it is black while hot, reddish-brown when cold [No. 74].

c. The Sulphides of Arsenio and some compounds of

o.led by

32 Of The Flame, And General

metallic sulphides with arsenides ; the sublimate is dark brownish-red while hot, but from reddish-yellow to red when cold [No. 80].

d. CSnnabar. — The sublimate is black, without lustre, and yields a red powder on being rubbed or scratched with a knife [No. 81].

e. Selenium and some selenides ; the sublimate appears only at a high temperature, is of a reddish or black color, and yields a dark-red powder ; at the open end of the tube the peculiar odor of selenium (resembling rotten horse-radish) is perceived [No. 87].

rgoes any

er physical ical consti- d, decrepi- atite. The

iling, points yellowish- brown, dirty pale-yellow on cooling, points to oxide of tin [No. 33] ; from white to brownish-red, yellow when cold, and fusible at a red heat, points to oxide of lead [No. 72]; from white to orange-yellow or reddish-brown, pale-yeliow when cold, and fusible at a bright red heat, points to teroxide of bismuth ; from red to black, and red again on cooling, points to sesquioxide of iron [No. 64].

Esa mi nation in a Glass Tube Open at Both Ends.

§ 13. A fragment of the substance, sometimes in form of a j)owder, is introduced into the tube to a depth of

o.led by

ROUTINE OF BLdWPIPE ANAL YSIS. 33

about lialf an Incli, the end to which it lies nearest slightly inclined, and heat applied. The air contained in the tube becomes heated ; it rises, escapes from the upper end, and fresh air enters from below. In this manner a calcination is effected, and many substances which remained unchanged when heated in a matrass, yield sublimates or gaseous products when subjected to this treatment, owing to the formation of volatile oxides.

By this means we can easily detect the presence of the following substances :

§ 14. Snlphar, — Sulphurous acid is formed, which is characterized by its peculiar odor and action on moist- ened litmus paper [No. 75].-

§ 15. Arsenic. — If present in sufficient quantity it yields a white and very volatile sublimate of arsenous oxide, con- sisting of minute octahedral crystals ; by application of gentle heat it may be driven from one place to another [No. 77]-

§ 16. Antimony. — White fumes of antimonous oxide are given out, which partly escape and partly condense in the upper part of the tube. The sublimate is a white powder, and may, if consisting of pure oxide of antimony, be volatilized by heat. In most cases, however, the oxida- tion proceeds farther, and antimonic oxide and antimon- ous oxide, a non- volatile white powder, is formed [No. 4,].

§ 17. Metallic Bismuth. — It is converted into oxide, which condenses at a short distance from the assay, and which, by heat, may be fused to brownish globules [No. 43]-

Merouiy and Amalgams — Yield sublimates of metallic mercury, consisting of smai! globules [No. 47].

§ 18. TelluriiuQ and Tellnrides.— Tellurous acid is pro-

o.led by

34 Of The Flame, And General

duced, which condenses in the upper part of the tube to a white non-volatile powder; on application of heat it fuses to colorless globules, thus distinguishing it from an- timony.

Selenium and Selenides — Evolve a gaseous oxide of a peculiar -dor, resembling that of rotten horse-radish [No. 87] ; a sublimate of selenium gray near the assay and red at a distance 13 sometimes formed.

Gzammation oa Charcoal alone.

§ ig. In examinations of this kind, particular attention must be paid to the odor of the escaping gases, and to the color and other properties of the rings, or coatings, which form on the charcoal around the assay-piece. The in- terior [reduction flame, E.. Fl.] and exterior [oxidation flame, O. Fl.] cones of the flame acting in an opposite sense, the phenomena produced will be very different ; hence two assays should always be made, exposing tlie substance first to the action of the O. Fl. and then to the action of the R. Fl. The following bodies undergo, when submitted to this treatment, characteristic changes.

§ 20. Arsenic. — It is volatilized without previous fusion, the Ch. is covered with a white Ct., which is far distant from the assay-piece, and which is produced by both the 0. Fi. and R. Fl. ; the Ct. is very volatile, and is easily driven away by the Blp. flame, to which it imparts a light- blue color", emitting the peculiar alliaceous odor charac- teristic of arsenic [No. 42].

§ 21. Antimony. — It enters readily into fusion and covers the Ch. with white oxide ; the ring is not so far distant from the assay-piece as in the case of arsenic ; it may be driven about by the O. Fl. and made to disappear with the R. Fl., which it colors a very pale-green, but is not

o.led by

Routine Of Slow-Pipe Analysis. 35

SO volatile as that of arsenic, and does not emit an allia- ceous odor. Metallic antimony, wlien fused on Ch. and heated to redness, remains a considerable time in a state of ignition without the aid of the Blp., disengaging, at the same time, a thick white smoke, which is partly de- posited on the Ch. around the metallic globule in white crystals of a pearly lustre [No, 41].

§ 22. Bismutll. — It fuses readily in both flames and covers the Ch. with oxide, which is dark orange-yellow while hot and lemon-yellow when cold. The yellow Ct. is usually surrounded by a yellowish- white ring, consist- ing of carbonate of bismuth. The Ct. is somewhat nearer the assay than that of antimony ; it may be driven away by both flames ; but unlike antimony and lead, does not impart any color to the R. FI. during the operation [No. 43].

§ 23. Lead.— It fuses easily, and coats the Ch. in both flames with oxide, which is dark lemon-yellow while hot and sulphur- yellow when cold ; in thin layers it is bluish- white and consists of carbonate. The Ct. is found at the same distance from the assay as that of bismuth ; jt may be driven away by both flames ; when played upon with the R. Fl. it imparls to it an aztire-blue color [No. 11].

§ 24. Cadmilini.—It fuses readily, and exposed to the O. Fl. it burns with a dark-yellow flame, emitting brown fumes of oxide, which cover the Ch. around and near the assay. This Ct. is very characteristic ; it is, when cold, of a reddish-brown color, in thiri layers orange-yellow ; it is easily volatilized by both flames, without imparting a coior to them. Beyond the coating a variegated border is sometimes seen [No. 44].

Indium. — It fuses readily, forming a coating very near the assay which is dark-yellow while hot, and yellowish-

o.led by

36 Of The Flame, And General

white when cold. It may be driven off with difficulty by the R. Fl., to which it gives a clear violet tint.

I 25. Ziao. — It fuses readily ; exposed to the O, FL it burns with an intensely luminous greenish- white flame, emitting at the same time a thick white smoke, which, partly condensing on the Ch., ratlier near the assay, covers it with oxide, yellow while hot and white when cold. The Ct. when played upon with the O. Fl. be- comes luminous, but does not disappear [No. 46].

i 26. Tin. — It fuses readily ; exposed to the O. Fl. it is converted into oxide, which may be blown away and thus be made to appear as a Ct. ; it is always found closely surrounding the sasay-piece, is slightly yellow and lumi- nous while hot, white when cold, and non-volatile in both flames. Exposed to the R. Fl. the molten metal retains its bright metallic aspect [No. 13].

§ 27. Silver.— When exposed for a long time to the action of the R. Fl. it yields a slight dark-red Ct. of oxide [No. 45].

§ 28. Selenium. — It fuses very readily in both flames with disengagement of brown fumes ; at a short distance from the assay a steel-gray Ct. of a feeble metallic lustre is deposited ; played upon with the R. Fl. it disappears with emission of a strong odor of rotten horse-radish, at the same time imparting to the flame a fine blue color [No. 87].

5 29. Tellurium. — It fuses very readily and coats the Ch. in both Sames wilh tellurous acid ; the Ct. is not very far distant from the assay ; it is of a white color with a red or dark-yellow edge ; played upon wilh the R. Fl. it dis- appears, imparting to the flame a green tinge.

§ 30. Besides the above-named metals there are some other substances which, when treated before the Blp. upon

o.led by

Routine Of Blow-Pipe Analysis. 37

Ch. cover it with coatings, which may be driven away when played upon with the 0. Fl., and which show in many cases a great resemblance to the substances already noticed. Among the bodies possessing this property the following are the most frequently occurring ones :

The sulphides of potassium, sodium, lithium, and proba- bly csesium and rubidium.

The chlorides of ammonium, potassium, sodium, and lithium.

The chlorides of mercury, antimony, zinc, cadmium, lead, bismuth, tin, and copper.

The sulphides, bromides, and iodides of potassium and sodium.

Zizamtnatlon in the Platinum -pointed Pincers. § 31. This experiment serves a double purpose. It ac- quaints us with the degree of fusibility of the assay, and shows the presence or absence of such sub a s h' 1 possess the property of imparting to the flame a 1 e ul ar color. Many metals, the sulphides, and some othe compounds act upon metallic platinum at a 1 te npe a ture; the fusibility, etc., of such substanc s o gl t to be tested on Ch. Others, again, fiise so easily that tl ej can not be held a sufficiently long time between the pincers to observe the color which they impart to the flame; they are most conveniently attached to the hook of the plati- num wire, which is best done by heating the wire to red- ness and then touching the powder of the assay with it ; a sufficient quantity generally remains adhering to the wire. Some minerals decrepitate violently as soon as they are touched with the flame ; in such cases, Berzelius advises to powder the substance very finely in an agate mortar with addition of a little water, to place one or two drops

o.led by

38 0/'- The Flame, And General

of the mixture on a. piece of Ch., and to gently heat it by iDeans of the Bip. flame until the mass lies loosely upon the Ch. J it may then be taken up and held by the pincers. The same process is advantageously employed with sub- stances which fuse only at a very high temperature. In all other cases the substance is roughly powdered and a thin piece which shows prominent edges selected for the experiment.

The assay is exposed to the action of the inner cone of. the flame, when the outer cone may exhibit the following changes of color: yellow, violet, red, green or blue.

§32. Yellow. — Soda and its salts cause an enlarge- ment of the outer flame, and impart, at the same time, an intense reddish-yellow color [No. i8]. The presence of other substances which also possess the property of color- ing the flame, but not in so high a degree, does not pre- vent the reaction. Silicates containing soda exhibit the same phenomenon to a smaller or greater extent, accord- ing to their degree of fusibility and the amount of soda which they contain [No. 62], With many salts of soda, which do not exhibit the reaction very distinctly, it can be produced by mixing the salt with some chloride of silver to a paste (v. § 5), fastening it to the hook of a thin iron wire, and then exposing it to the action of the inner

§33. Violet — Potassa and most of its salts, with the exception of borate and phospliate, impart to the outer flame a distinct violet color [No. 15]. Also the salts of rubidium and caesium and the compounds of indium, but these are rare as compared with the potassa. The pres- ence of a salt of soda prevents the potassa reaction, in which case the flame is viewed through blue cobalt glass, or a solution of indigo. Lithium also destroys the

o.led by

Routine Of Bt.Ow-Pipe Analysis. 39

potassa flame, unless in very minute quantities. Silicates of potassa must be free from soda and litliia, and easily fusible, at least on the edges.

§ 34. Red.— Lithia and its salts impart to the outer flame a fine carraine-red color [No. 63]; the chloride of lithium shows the reaction better than any other salt. The presence of a salt of potassa does not prevent the reac- tion ; the presence of even a small quantity of a salt of soda changes the color to yellowish -red, and a larger quantity prevents the reaction entirely.

Chloride of strontium and some other salts of strontia, ex. gr. the carbonate and the sulphate, color the outer flaroe, immediately or aiter a while, carmine-red [No. 57]. The presence of considerable baryta prevents the reaction. The carbonate and sulphate of strontia show the reaction remarkably well when mixed with chloride of silver and heated on iron wire (v. % 5).

Chloride of calcium, calcareous spar, many compact limestones, and fluorite, color the outer flame, imme- diately or after a while, red ; the color is not so intense as that produced by strontia. Gypsum and anhydrite im- part at first a pale yellow, afterward a red color of little intensity [No. 55]. Fluorite gives at first a yellowish flame, but afterward an intense yellowish-red [No. 6].

§ 35. Green. — Baryta. Chloride of barium, carbon- ate and sulphate of baryta, color the outer flame yellow- ish-green. The presence of lime does not prevent the reaction [No, 58].

Oxide of copper and some of its salts, ex. gr. the car- bonate and nitrate, impart to the outer flame a fine eme- rald-green color. Compounds of iodine and copper, and some silicates containing copper, ex. gr. dioptase and chrysocoHa, act in the same manner [No. 73]. Thallium,

o.led by

40 OF TrrE flame, and general

fused on charcoal, also its salts, give aji intense green

Phosphoric acid, phosphates, and minerals containing phosphoric acid, especially if moistened with sulphuric acid, impart to the outer flame a bluish - greeii color [No. 3].

Bovacic acid colors the outer ilame yellowish -green (greenfinch color) [No. 5]; if a small quantity of soda is present the color is mixed with yellow. Minerals con- taining boracic acid should be pulverized and moistened with sulphuric acid.

Molybdic acid, oxide of raolybdenuin, and molybde- nite color the outer flame yellowish-green, in which the yellow is stronger than in baryta [No. 83].

Tellurous acid fuses, emits white fumes, and colors the outer flame green.

§ 36. Blue. — Arsenic and some arsenides, ex. gr. smal- tite and niccolite [No. 82], when Ireated on Ch., impart a light-blue color to the outer flame. Some arsenates, ex. gr. scorodite and erythrite, exhibit the same phe- nomenon in the forceps.

Antimony, fused on Ch. in R. Fl., is surrounded by a feeble greenish-blue flame [No. 41].

Metalliclead, fused on Ch. in R. Fl., is surrounded by an azure-blue flame. Many salts of lead, heated in the for- ceps or on platinum wire, impart an intense azure-blue color to the outer flame [No. 11].

Chioride of copper colors the outer flame intensely azure-blue; after a while the color becomes green, owing to the formation of oxide of copper [No. 37].

Bromide of copper colors the outer flame greenish-bJue ; after a while the color changes to green.

Selenium, fused on Ch. in R. Fl., vaporizes with an azure-blue flame.

o.led by

Routine Of Blow-Pipe Analysis. 4I

Exami nation with Boras and Salt of Phospliotus.

§ 37. The esamination of the assay with borax and salt of phosphorus is eminently adapted to detect the presence of metallic oxides, a great number of them possessing the property of being at a high temperature dissolved by these fluxes with a peculiar color. Unoxidized metals and metallic sulphides, arsenides, etc., differ in this re- spect very materially from the pure oxides ; hence it is necessary, before performing the experiment, to convert all such substances into oxides. This is elTecCed by calci- nation, or roasting on Ch. or in an open glass tube. The finely powdered assay is placed on Ch. and alternately treated with the O. Fl. and R. Fl., and this process is repeated until the substance no longer emits, while in the incandescent state, the odor of sulphur or arsenic. The heat must never be raised so high as £0 cause fusion, and between every two succeeding calcinations the assay should be taken from the Ch. and freshly powdered.

The experiment with borax is generally made on plati- num wire, where the color of the bead is more readily observed; Ch. is used only in such cases where the sub- stance under examination contains metallic oxides which are easily reduced. It is not sufficient to observe the color of the bead after cooling ; but all changes of color which take place during the action of the flame, and through all the various stages of cooling, should be care- fully noticed.

Some substances possess the property of forming a limpid glass, with borax, which preserves its transparency on cooling, but which, if slightly heated in the O. Fl., becomes opaque when the flame strikes it in an unequal or intermittent manner. This operation has received the

o.led by

43 Of The Flame, And General

name of "flaming," and any substance thus acted upon is said to become "opaque by flaming."

The third and fourth columns of Tables I. and II. exhibit the behavior of the most important oxides to borax and salt of phosphorus.

In Table III. the oxides are arranged with reference to the color which they impart to the beads in O. Fl. and R, Fi. It will be noticed that the colors produced in the S. Ph, are different from those produced in borax.

C:s ami nation fcitti Carbonate of Soda.

§ 38. In subjecting a body to the treatment of Sd. we have to direct our attention to two points.

Some substances unite with Sd. to fusible compounds, others form infusible compounds, and others again are not acted upon at all ; in the last case the Sd. is absorbed by the Ch. and the assay is left unchanged. With Sd. form fusible compounds with effervescence ;

§ 39. Silicic Acid. — It fuses to a transparent glassy bead which, after cooling, remains transparent if the Sd. has not been added in excess [No. 54].

Titanic Acid, — It fuses to a transparent glassy bead which, when cold, is opaque and of crystalline structure [No. 65].

Tungstlo and Molybdlc Acids. — The mass, afler the union has been effected, is absorbed by the Ch. [No. gt and No. 34].

Tantalic, vanadic, and the acids of niobium, also yield fusible compounds.

The salts of baryta and strontia form with Sd. fusible compounds which are absorbed by the Ch. [No. 57 and No. 58].

g 40. The second point to be observed is the ehniina-

.,t.db,

Routine Of Blow-Pipe Analysis. 43

tion of metallic matter. Of tr.e metallic oxides, when treated with Sd. on Ch. in R. FL, are reduced; the oxides of the noble metals and the oxides of arsenic, anti- mony, bismuth, indium, cadmium, copper, cobalt, iron, lead, mercury, nickel, tin, zinc, molybdenum, tungsten, and tellurium. Of these, arsenic and mercury vaporize so rapidly that frequently not even a coating is left on the Ch. Antimony, bismuth, cadmium, lead, zinc, and tel- lurium are partly volatilized and form distinct coatings on the Ch. The non-volatile reduced metals are found mixed up with the Sd. To separate them from the ad- hering Sd. and Ch. powder, we may proceed in the fol- lowing manner ;

The fused mass of Sd. and metal, and the portion of the Ch. immediately below and around the assay, is placed in the little agate mortar, rubbed to powder, the powder mixed with a little water, and stirred up. The heavy metallic particles settle to the bottom, part of the Sd. dis- solves, and the Ch. powder remains suspended in the water. The liquid is carefully poured off, and the residue treated repeatedly in the same manner until all foreign matter is removed. The metal remains behind as a dark heavy powder, or, when the metal is ductile and easily fusible, in the shape of small flattened scales of metallic lustre. These may be examined with the magnifying- glass, and also with the magnet. If the substance under examination contains several metallic oxides, the metallic mass obtained is usually an alloy, in which the several metals may be recognized by processes to be described hereafter. It is only in some exceptional cases that sepa- rate metallic globules are obtained, ex. gr. in substances containing iron and copper.

For a more detailed account of the behavior of the

o.led by

44 Of The Flame, And General

various metallic oxides under this treatment, see the sec- ond column of Tables I. and II.

§ 41. The examination with Sd. is usually performed on Ch. in the R. Fl., and, as a general rule, the flux is added successively in small portions. It is sometimes better to form the pulverized assay into a paste with moistened soda before placing it upon the coal. This is particularly necessary when the Esay is to be tested for its fusibility with Sd., since a great many minerals, etc., behave very differently with different quantities of the flux.

§ 42. Instead of carbonate of soda, the neural oxalate of potassa or cyanide of potassium may be advantageously used for all experiments of reduction, since these reagents exercise a more powerful reducing action than common Sd. They are, for this reason, frequently employed when the presence of such metallic oxides is suspected, whose conversion into metals require high temperatures and the aid of a very efficient deoxidizing agent.

A list of the oxidized minerals arranged according to their fusibility and behavior with carbonate of soda may be found under its appropriate head.

Examinatian inrith Solution of Cobalt.

§ 43. A few substances, when moistened with a solution of nitrate of cobalt and exposed to the action of the O, FL, assume a peculiar color. The use of this test is, however, very limited, since the reaction can only clearly be seen in such bodies which, after having been acted upon by the O. F!., present a white appearance, or nearly so.

§ 44. Substances which are sufficiently porous to absorb a liquid, are merely moistened with a drop of S. Co., placed into the platinum-pointed forceps, and treated with

o.led by

Routine Of Blow-Pipe Analysis. 45

the O. Fl. Other substances must be powdered, the powder placed on Ch., moistened with a drop of S. Co., and treated as above. The color can only be distin- guished after cooling. A bluish color, of more or less purity, but rather dull, indicates the presence of alumina [No. zi] ; and a pale-reddish color [flesh-color] that of magnesia [No. 59]. It must, however, be borne in mind, that the alkaline and some other silicates, when heated with S. Co. to a temperature above their fusing point, also assume a blue color, owing to the formation of sili- cate of cobalt. In testing for alumina, therefore, the beat must not be raised so high as to cause fusion of the assay. In testing for magnesia this precaution is not necessary ; on the contrary, the color will appear the brighter and the more distinct, the higher the temperature to which the assay was exposed. The alumina and magnesia re- actions are prevented by the presence of colored metallic oxides, which generally produce a gray or black mass, unless present in too minute quantity.

§ 45. Among the oxides of the heavy metals, those of zinc and tin assume characteristic colors with S. Co. The reaction is best seen when the assay, alone or mixed with Sd., is exposed to the R. Fl. on Ch. The ring of oxide which is deposited around the assay is then moistened with S. Co. and treated with the O. Fl. Oxide of zinc takes a fine yellowish-green, and oxide of tin a bluish- green color [No. 2,() and No. 33].

I 46. Besides the compounds above mentioned there are some others which, when exposed to the action of S. Co. and Fl. , experience a change of color. These bodies are either of very rare occurrence, or the change pro- duced in them is not sufficient to be of much importance. In fact only a few colorations are of much use in the

o.led by

46 O' The Flame, And General

determination of substances, those of alumina, magnesia, zinc, and tin.

The following list of compounds gives the more definite colorations :

ff. Blue, alumina, silica,

b. Violet, zirconia (dirty- violet), phosphate and arse- nate of magnesia (fuse at the same time).

c. Flesh color, magnesia, tantalic acid.

d. Brownish-red, baryta.

e. Gray, strontia, lime, glucina, niobic acid.

/. Green, oxide of zinc (yellowish -green), of tin (bluish -green), titantic acid (yellowish-green), hyponio- bic acid (dirty green), antimonic acid (dirty dark-green).

o.led by

Chapter Iii.

Special Reactions fop the Detection of Certain Sub- stances when in Combination with Others,

§ 47. The preceding chapter and accompanying table show the changes which many of the simple chemical compounds undergo when heated, or when treated with the usual blow-pipe reagents. The reactions are suffi- ciently characteristic to distinguish the various compounds from each other, so that, when any of the above-named substances in a pure state is under examination, there is no difficulty to determine its nature. This, however, is not of frequent occurrence, and in the majority of cases the body to be tested will be of a more complex nature. The results of the experiments will vary accordingly. For instance, an ore of cobalt, containing iron, will not impart to the bead of Bx, or S. Ph. in the 0. Fl. a blue color, but a green one, resulting from the mixture of the blue of cobalt and the yellow of iron ; lead, when ac- companied by antimony, deposits a dark-yellow coating on Ch, resembling that of bismuth, etc. In such cases we may often, by attentively observing all the phenomena which present themselves, and by carefully comparing the results obtained by the various experiments detect mmy, if not all, of the components of the sub'itance under ex- amination. Sometimes we attim this end by varying the order, or by introdui rag luxiliary agents into the series of experiments ; and m other cases, again, it is only to be arrived at by subjecting the assay to treatments different from those mentioned m the preceding pages

o.led by

48 Special Reactions.

This chapter conlains the principal reactions for the detection of substances which require the application of peculiar agents, and the methods for ascertaining the presence of certain bodies when in combination with others. The alphabetical arrangement will be found of practical use.

§ 48. Ammonia, — Small quantities of animoniaare best detected by mixing the powdered assay [No. 19] with some carbonate of soda or caustic potassa, introducing the mixture into a glass tube, sealed at one end, and applying heat. The escaping gas is characterized by its odor, and by its action on reddened litmus paper. White clouds are formed if a glass rod moistened with hydrochloric acid is held before the end of the open tube. From the appearance of this reaction we are, however, not authorized to infer the preexistcnce of ammonia in the assay, since from organic matter containing nitrogen, when subjected to this treatment, ammonia is evolved as a product of decomposition.

Antimony. — The reactions of antimony and its com- pounds, see § II, § 16, § 21, § 36, and Table II., 1.

§ 49. In presence of lead or bismuth, antimony can- not be detected by its Ct. alone on Ch. In this case the metallic compound [No. 48 or No. 85] is treated with vitrified boracic acid on Ch,, the flame being so directed that the glass is always kept covered with the blue cone, the metallic globule being on the side ; by this means the metals become oxidized, the oxides of lead and bismuth are absorbed by the boracic acid, and the oxide of anti- mony will form a ring on the Ch., provided the tempera- ture was not raised too high.

§ 50. When combined with metals from which it is not easily separated, ex. gr. copper, the evaporation of the

o.led by

Special Reactions. 49

antimony takes place so slowly that no distinct Ct. is pro- duced. In this case the assay [No. 86] is treated with S. Ph. on Ch. in the O. Fl., until the antimony, or at least part of it, has become oxidized and entered into the flux. The glass is now removed from the metallic globule and treated on another place of the Ch. with metallic tin in the R. Fl. ; the presence of antimony will cause the glass to turn gray or black on cooling [Table II., i]. Bismuth behaving under these circumstances in precisely the same manner, the presence of this metal makes the reaction not decisive for antimony. The hu- mid way has then to be resorted to. See § 59.

§ 51. When the oxides of antimony are accompanied by such metallic oxides which, when reduced on Ch., fuse with the metallic antimony to an alloy, as is ex, gr. the case with the oxides of tin and copper, the latter can- not be recognized by a simple reduction. The oxides have to be treated with a mixture of Sd. and Bx. on Ch. in the R. Fl. The little metallic globules are separated from the flux, and fused with from three to five times their own volume of pure lead and some vitrified boracic acid in the R. Fl., care being taken to play with the flame only on the glass. Oxide of antimony is volatilized, de- positing the characteristic ring, while the oxides of the other metals are absorbed by the boracic acid.

§ sa. The sulphides of antimony, when heated in the open glass tube, show the reaction mentioned % 16. When accompanied by sulphide of lead [No. 89], only a small part of the antimony is converted into oxide, which sub- limes; the remainder is changed into a white powder consisting of a mixture of antimonic acid and oxide of antimony, sulphate of lead, and antimonate of lead. When a compound containing sulphide of lead or bismuth.

o.led by

50 Special Reactions.

besides sulphide of antimony, is heated on Ch. in the R. Fl., a Ct, is deposited consisting of oxide of antimony mixed with sulphate of lead or bismuth, and, nearer to the assay, a yellow one of the oxides of lead or bismuth ; how in such a case the presence of antimony may be as- certained V. § 87.

§ 53. To detect a small amount of sulphide of antimony in sulphide of arsenic, Plattner strongly recommends the following method, by which he obtained very decisive and satisfactory results : The assay [No. 88] is introduced into a glass tube, sealed at one end, and gently heated j the sulphide of arsenic is volatilized, and the greater part of the sulphide of antimony remains as a black powder in the lower end of the tube ; this end is cut off, and the black substance taken out and transferred to a tube open at both ends. By applying heat the characteristic anti- mony-reaction will appear.

Arsenic. — The reactions of arsenic and its compounds, see g ir, g ig, g 20, § 36, and Table IL, 2.

§ 54. All metallic arsenides yield, when heated in the open glass tube, a sublimate of arsenous oxide (v. § 15), and most of tliem evolve a garlic odor (v. § 20), when heated on Ch. in R. Fl. [No. 77]. Some metals, ex. gn nickel and cobalt, have a great afSnity for arsenic, so that, when only a small quantity of the latter is present, the characteristic odor is not observable ; in such cases it is sometimes produced when the metallic compound is fused on Ch. with some pure lead in the O. Fl.

§ 55. The sulphides of arsenic, heated in the open glass tube, evolve sulphurous acid and yield a sublimate of arse- nous oxide. To show in a very decisive manner the pres- ence of arsenic in any of its combinations with sulphur, the powdered assay [No. 80] is mixed with four volumes of neutral oxalate of potassa and a little charcoal powder.

o.led by

Special Reactions. 5 I

or with six parts of a mixture of equal parts of cyanide of potassium and carbonate of soda, tlie mass introduced into a tube sealed at one end, and heat applied, at first very gently but gradually raised to redness. A ring of metallic arsenic will be deposited in the colder part of the tube. (Fig. i8.)

Fig. IB.

% 56. When sulph-arsenides are heated on Ch., the whole of the arsenic, especially when only small quantities are present, may pass off in combination with sulphur ; but when such compounds [No. 88] are mixed with from three to font parts of neutral oxalate of potassa or cyanide of potassium and exposed to the E.. Fl., sulphide of potas- sium is formed and the arsenic escapes with its peculiar odor, if not combined with cobalt or nickel.

§ 57. To detect a very small quantity of arsenous acid, the following way may be purstied: a glass tube provided with a small bulb at one end is close above it narrowly drawn out ; the assay [No. 38] is introduced into the bulb, and a charcoal splinter placed Into the tube ; the narrow aperture through which the tube communicates with the bulb prevents the Ch. from coming in contact with the substance. The tube is then heated to redness at the place where the charcoal splinter lies, and as soon as this is in- candescent, heat is also applied to the bulb. (Fig, 19.) The arsenous oxide is volatilized, and its vapors, while passing over the red-hot charcoal, become reduced and deposit a black metallic ring of arsenic in the colder part of the tube. By cutting the tube below the ring and heating this part by the flame of a gas-lamp, the arsenic is volatilized, thereby emitting its characteristic odor.

o.led by

52 Special Reactions.

% 58. To show the presence of arsenic in arsenites and arsenates, it will in most cases be sufficient to mix the

Fis. 19.

substance [No. 38] with carbonate of soda and heat it on Ch. in E.. Fl. Sometimes it is necessary to treat the assay with a mixture of carbonate of soda and cyanide of potassium in the manner mentioned, 55 ; and in other cases again, where but small quantities of arsenous or arsenic oxide are combined with metalhc oxides which are readily reduced, recourse must be had to the humid way.

Bismuth. — The reactions of bismuth and its compounds, see § 12, § 17, § 22, and Table IL, 3.

I 59. Bismuth, when alloyed with other metals, or when as sulphide in combination with other sulphides, is in many cases, and most especially so when accompanied by lead or antimony, not to be detected with certainty by the ring which it deposits on Ch. In such a ce the assay [No. 49] is treated on Ch. tintil a copious yellow Ct. is formed. The Ct. is carefully scraped off from the Ch. and dissolved in S. Ph. on platinum wire with the O, Fl. The colorless bead is removed from the wire, placed on Ch., a little metallic tin added, and the whole exposed to the R. Fl. If bismuth was present, the glass assumes.

o.led by

Special Reactions. S3

on cooling, a dark-gray or black color. The oxides of

antimony showing the same behavior, the assay, if not

q 'l f f t' n 1 s to be treated on Ch in ihe

OF has b d nd the

m g miss d h p as above

m d A hesub-

p ent sin-

g us h p b me of

p p d ng the

as p lamp,

d m p T soluble

d g p of lead

d as m of the

d bs d hi ony, if

p se m IS d

Th d h d ed with

h d w ud present.

A fi b h w ewarm

filtrate with S, Ph., which is collected and tested with S. Ph. The bead on platinum wire is colorless or only tinged with yellow, but on coal with tin in R, Fl. becomes dark-gray on cooling, like oxide of bismuth, and may be recognized as such on coal.

According to Von Kobell, any compound of bismuth treated before the Blp. with a mixture of equal parts of iodide of potassium and sulphur on a large coal, gives a beautiful and very characteristic red coating, at quite a distance from the assay.

Cornwall suggests the following method to detect bis-

American Chemisl, March, 1872.

o.led by

54 Special Reactions.

muth in presence of lead and antimony : To the mix- ture of the three oxides, an equal volume of sulphur is added, and the whole treated before the Blp. in a deep cavity on coal with the blue flame for a few moments. The resulting fused sulphides are removed to a flat coal and treated alternately with the O. Fl. and R. Fl. until the antimonial fumes have nearly ceased, and an impure blue lead flame appears. The residue is powdered, and an equal part of a mixture of i part of iodide of potas- sium and 5 of sulphur, by weight, added. This is then heated in an open tube about four inches long and not less than one-third of an inch wide, over a Bunsen gas- burner, or spirit lamp. A distinct red bismuth subhmate is formed, about one-third of an inch above the yellow sublimate of lead.

Care must be taken not to confound with the bismuth sublimate a sublimate of iodine, which may condense on the upper part of the tube, but at a greater distance from the assay.

§ 60. Boracio Acid. — With many borates, which do not impart to the outer flame the peculiar yellowish -green color jv. § 35], this reaction may be produced by re- ducing the substance [No. 2] to powder, adding a drop of concentrated sulphuric acid, fastening the mixture into the hook of the platinum wire, and playing on it with the blue cone of the flame.

§ 61. Another way, ai.vi by which even a very small quantity of boracic acid io salts and minerals may be detected, is : to reduce the substance to a very fine pow- der, to mix it with from 3 to 4 parts of a mixture of 4i parts of bisulphate of potassa and i part of fluor-spar, perfectly free from boracic acid, and to knead the whole with a little water into a thick paste. This mass is then

o.led by

Special Reactions. 55

fastened to a platinum wire, and exposed to the blue cone of the flame. While the mass enters into fusion fluobora- cic acid is formed, which, on escaping, colors the flame intensely yellowish- green. The reaction appearing some- times only for a few seconds, the flame should be very attentively watched during the whole time of the experi- ment. According to Mcrlet, it is often necessary, in order to obtain a sure result, to employ with one part of the assay three or four of the flux.

§62. Bromine, — Bromides treated with S. Ph. and oxide of copper on platinum wire, or treated with sul- phate of copper on silver foil, show the sime reaction as chlorides (v. § 66), with this difference, that the blue color of the outer flame is rather greenish, especially on the edges [No. i6J. When the bromine is all driven off the green flame of the copper alone remains

§ 63. To discriminate bromides from chlorides more distinctly, the broroide is fused with bisulphate of potassa, both in the anhydrous state, in a small matrass with long neck. Sulphurous acid is evolved, and the matrass is filled with yellow vapors of bromine, characterized by their peculiar odor. The color of the gas is only clearly seen by daylight. Bromide of silver may be distinguished from chloride of silver by the asparagus-green color -which it assumes when exposed to the sunlight after fusioii with bisulphate of potassa.

The presence of iodine, on account of its violet vapors, renders the bromine reaction somewhat uncertain.

Cadmium. — The reactions of cadmium and its com- pounds, see §g, II, 24, and Table II., 4.

% 64. To detect a very small quantity of cadmium, one per cent, or less, in zinc or its ores, the pulverized assay

o.led by

$6 Special Reactions.

is mixed with Sd. and exposed for a short time to the R. Fl. on Ch. A distinct Ct. of oxide of cadmium is de- posited. The zinc being less volatile, volatilizes only with continued blowing [No. 53].

§ 65. Chlorine. — Some oxide of copper is dissolved by means of the O. Fl. in a bead of 3. Ph. on platinum wire, until the glass is nearly opaque. Some grains of the pul- verized assay [No, 18] are then made to adhere to the bead, and both heated with the tip of the blue cone of the ilame. If chlorine is present the flame now assumes an intense azure-blue color, owing to the formation of chlo- ride of copper (v, § 36). This test is very delicate, and will show the presence of a very minute quantity of chlo- rine. Bromine produces a similar flame.

§ 66. Another method is to place on silver-foil some protosulphate of iron, or some sulphate of copper, to moisten it with a drop of water, and then to add the assay [No. i8]. After a while the silver will be found blackened. Substances which are insoluble in water have previously to be fused with a little Sd. on platinum wire, to form a soluble chloride [No. lo].

Chlorides, when moistened with sulphuric acid and exposed to the BIp. flame, impart to it a faint green col' oration, which, however, is generally confined to the inner cone, and is quantitatively of much less intensity than that produced with borates. A small amount of boracic acid, when occurring together with a chloride, cannot, ther.i- fore, be detected by the method mentioned § 60.

§ 67, Chromium.— Oxide of chromium gives very char- acteristic reactions with the fluxes on platinum wire (v. Table 11., 6), but when accompanied by a large quantity of iron, copper, or other substances which alstf intensely

o.led by

Special Reactions. S7

color the Ex. and S. Ph. beads, the chromium color fre- quently becomes very indistinct.

§ 68. In such a case, and when the chromium is not jo combination with silicic acid, its presence may be detected in the following manner: The assay-piece [No. 71] is re- duced to a fine powder and mixed with about twice its own volume of a mixture of equal parts of Sd. and nitre. The mass is fastened into the hook of a thick platinum wire, or placed into a small platinum spoon, and treated with a powerful O. Fl. An alkaline chromate is formed which is dissolved in water, the solution supersaturated with acetic acid, boiled, and a crystal of acetate of lead added. If chromium was present, a yellow precipitate of chromate of lead will appear. The precipitate may be collected on a filter and tested in the Ex. and S. Ph. beads, when the characteristic chromium-reactions will be produced.

Silicates which contain only a little chromium, but much iron or other coloring oxides of metals, are not decom- posed by nitre. In this case a pulverized mineral is fused on coal in the O. Fl. with one to one and a half times its volume of soda, and one-half to three-fourths parts of borax to a clear bead ; this is pulverized and evaporated to dryness with hydrochloric acid. The chlorides thus formed are dissolved in water, the silica filtered otf, the protochloride of iron in solution changed to sesqui chloride by boiling with a few drops of nitric acid, and the bases, sesquioxide of chromium, iron, alumina, etc., precipitated by ammonia from the acid solution. The precipitate is collected on a filter, washed, and fused with soda and nitre as above. By this means chromates of the alkalies are formed, which can be decomposed by acetic acid and acetate of lead as already described.

o.led by

so SPECIAL REACTIONS.

Cobalt. — The reactions of cobalt, see Table II., 7,

§ 69. To detect cobalt, when in combination with other tnetals, v. § 83,

To show its presence in arsenides, the assay [No. 78] is placed on Ch. and heated until fumes of arsenous acid no longer are emitted. (Lead and bismuth, if present, form the characteristic coatings.) Bx. is now added and the heat continued until the glass appears colored. If the color is not pure blue, the presence of iron is indi- cated. The glass is in this case removed from the globule, and the latter treated repeatedly with fresh quantities of Bx. mitil the pure cobalt-color is obtained. Nickel and cop- per, if present, do not enter into the flux before the whole of the cobalt is oxidized. If we wish to ascertain the presence of these metals, the glass which is colored by cobalt is removed from the globule, and the latter treated with fresh portions of Bx. in the O. Fl. until the color of the bead becomes brown, indicative of nickel. The glass is again removed and the globule treated with S. Ph. in the O. Fl.; when copper is present the bejid assumes a green color, which remains unaltered on cooling. Treated with tin on Ch. the glass turns opaque and red from sub- oxide of copper.

§ 70. To detect cobalt in sulphides, the assay [No. 79] is heated on Ch. in the R. Fl. until all volatile substances are driven off, the remaining mass reduced to powder, well calcined, and the calcined mass treated with Bx. on Ch. in the O. Fl. If cobalt is the only coloring metal present, the bead will exhibit a pure blue color ; a small addition of iron will make the glass appear green while hot, but blue when cold. Copper and nickel, when present to some extent, will prevent the cobalt-color being distinctly seen. The bead is in this case exposed to the R. Fl. until

o.led by

Special Reactions. 59

it appears transparent and flows quietly; the oxides of copper and nickel are by this means reduced, Eind the pure color of cobalt, or that of cobalt mixed with iron, becomes apparent. The separation of the metals may be promoted by adding a little pure lead, and the substance freed from an excess, by treating it alone on coal, after which it is fused in the O. Fl. with S. Ph. to detect nickel and copper.

Copper. — 'The reactions of copper and its compounds, see §§ 3S, 36, and Table 11., 8.

§ 71. The red color which copper imparts to the Bjc. or S. Ph. bead, when heated on Ch. in the R. Fl. in con- tact with tin (v. Tabic 11. , 8), is very characteristic, and will in most cases clearly show the presence of this metal. But if only a small quantity of copper is associated with other metals, the reaction is not easily obtained ; in this case we may proceed as follows :

The assay [No. 89, or No. 86, or No. 85] is placed on Ch. and played upon with the 0. Fl. until antimony and other volatde metals are driven off. Some vitrified boracic acid is fused on Ch, to a glassy globule, the assay placed close to it, and the whole covered with a large R.. Fl. When the metallic globule begins to assume a bright metallic surface, the flame Js gradually converted into a sharply-pointed blue cone, which is made to act only on the glass, leaving the metallic globule untouched, and so situated that it touches the glass on one side, and on the other side is in close contact with the Ch. During this process lead, iron, cobalt, part of the nickel, and such of the more volatile metals as were not entirely removed by the previous calcination, as bismuth, antimony, zinc, etc., become oxidized, and their oxides partly volatilized and partly absorbed by the boracic acid. The remaining

o.led by

6o SPECIAL REACTIONS.

metallic globule is then removed from the flux and treated on Ch. with S. Ph. in the O. Fl., when the copper is oxi- dized and dissolved. The limpid bead is then re-fused in the R. Fl. with addition of tin. A trace of copper may thus be made to produce distinctly the characteristic re- action, rendering the cold bead distinctly red and wholly or partially opaque.

§ 72. To show the presence of copper in compounds which contain much nickel, cobalt, iron, and arsenic, the assay [No. 82] is first treated with Ex. on Ch. in the R. Fl. , when the greater part of iron and cobalt are dissolved. The remaining globule is then mixed with some pure lead, and treated as shown § 71. Arsenic is for the most part driven off, and the rest of the iron and cobalt, with some nickel, absorbed by the boracic acid. The globule is removed from the glass and treated with S. Ph. in the 0. Fl.; dark-green while hot, and somewhat lighter green when cold (produced by the mixture of the yellow of nickel and the blue of copper), indicates the presence of copper.

To detect copper when in combination with tin v. § i ro.

§ 73. To detect copper in sulphides, the pulverized assay [No, 76] is calcined, and the calcined mass treated as above, or, when the amount of copper is not very small, simply treated with Bx. or S. Ph. on Ch. in the O. Fl., and subsequently with addition of tin in the R. FL The presence of copper is then shown by the red color and the opaqueness of the glass on cooling. This reaction ia only prevented, or at least made indistinct, by antimony or bismuth, which cause the glass to turn gray or black. In this case the assay is, after calcination, mixed with Sd. Bx., and some piire lead, and the mixture fused on Ch. in the R. Fl. The metallic globule is then heated on Ch. to

o.led by

Special Reactions. 6 1

drive off the antimony, and afterwards treated with boracic acid as above.

§ 74. When a mineral which contains copper is heated in the blue cone, the outer cone of the flame frequently assumes a green, or if the metal is in combination with chlorine, an aaure-blue color. This reaction, if not pro- duced by heating the substance alone, may sometimes be elicited by adding a drop of concentrated hydrochloric acid to the pulverized assay [No. 73], evaporating to dry- ness, mixing the dry powder with a little water to a stiff paste, fastening this into the hook of a platinum wire, and then exposing it to the blue cone of the flame.

§ 75. Fluorine. To detect fluorine in those minerals where it occurs only as an accessory element in combina- tion with weak bases, and which at the same time contain water, a small piece of the substance [No. 6] is placed into a glass tube sealed at one end, a wet Brazil-wood paper introduced into the open end, and heat applied. Fluoride of silicon and hydroftuoric acid are evolved ; the former is decomposed by the watery vapor, and deposits a ring of silica not far distant from the assay, and the latter turns the red color of the test-paper to straw-yellow. Mica, containing not more than f per cent, of fluorine, shows the reaction very distinctly.

§ 76. To show the presence of fluorine in minerals where it is united with strong bases, the finely powdered assay [No. 6] is mixed with one to four parts of bisulphate of potassa and introduced into a glass tube, sealed at one end. Heat is applied until sulphuric acid begins to escape. The sides of the tube become covered with silicic acid, resulting from the decomposition of the gaseous fluo- ride of silicon. The tube is cut off close above the fused mass, cleaned with water, and carefully dried with blot-

o.led by

62 Special Reactions.

ling paper. The dulled appearance of the indicates the presence of fluorine.

§ 77. Another process, and by which the presence of fluorine in all kinds of compounds may be shown, is to mix the pulverized assay with some S. Ph. which has pre- viously been fused on Ch. and then reduced to powder; to place the mixtiu-e on platinum foil, which is connected with an open glass tube in such a manner as to constitute a kind of tubular continuation to the former, and to heat with the blow-pipe flame until the mass enters into fusion. If the flame is so directed tliat the products of decomposi- tion are made to pass through tlie glass tube, and a moist- ened Brazil-wood paper is introduced into the other end, the presence of hydrofluoric acid is indicated by the change of color which the latter experiences, and often by its pun- gent odor. In some cases the glass will also be dulled, or a deposit of silicic acid be formed. This test is very delicate.

§ 78. Gold. When gold is in combination with metals which are volatile at a high temperature, ex. gr, tellurium, mercury, antimony, it is only necessary to heat the alloy on Ch. with the O. Fl., when the gold remains behind in a pure state, and may be recognized by its physical proper- ties. Lead is removed by the process of cupellation, as explained in § 103.

§ 79. When associated with copper, the presence of which is easily detected by S. Ph. on Ch., the alloy, for example gold-coin, is dissolved in pure melted lead, and the new compound subjected to the process of cupel- lation on bone-ash. Copper is by this means entirely re- moved. To test the remaining globule for silver, it. is treated with S. Ph. on Ch. in the O. Fl. ; the silver is gradually oxidized and dissolved by the glass, which when

o.led by

Special Reactions. 63

cold assumes an opal-like appearance. To determine ap- proximately the relative proportions of the two mctaJs, the metaJUc globule is taken from the cupel, placed in a small porcelain dish containing some nitric acid, and heat ap- plied. If the alloy contains twenty-five per cent, of gold or less, it turns black, the silver is gradually dissolved, and the gold remains behind as a brown or black spongy or pulverulent mass. If the alloy contains more than twenty- five per cent, of gold, the globule turns also black, but the silver is not dissolved. If both metals are present in about equal proportions, the globule remains unaltered. If the amount of gold is considerable, it is indicated by the color of the alloy.

In both of the latter cages it must be fused on coal with borax and at least twice its weight of silver, free from gold, and then treated with nitric acid, when the separa- tion will be complete. To form a gold button, it must be well washed with distilled water and fused on coal with borax, and it will then have the pure gold color and bright surface.

I 80. Wlien associated with metals, which per se are infusible before the biow-pipe, as ex. gr. platinum, irid- ium, palladium, the metallic globule obtained by cupella- tion shows much less fusibility than pure gold. The exact nature of the foreign metals cannot be ascertained before the Bip.; the humid way must be resorted to.

§81. Iodine. Iodides, tested with a S. Ph. bead which is saturated with oxide of copper, as shown § 65, impart to the outer flame a fine green color [No. 17].

Fused with bisulphate of potassa in a glass tube closed at one end, violet vapors are evolved, iodine sublimes, and sulphurous acid escapes.

To detect a small amo\mt of iodine in mineral water

o.led by

64 Special Reactions.

which has been freed from the greater part of its chloride of sodium by evaporation, a solution of starch in boiling water, with chlorine water, is genarally employed, a blue insoluble compound being thus formed if iodine is present. A few drops of nitric acid may be used in place of the chlorine water.

§ 8a. Another method, which is said to sxirpass in deli- cacy even the reaction with starch, is to mix the substance with a little air-slaked lime, or a mixture of carbonate of lime and quicklime, to dry the mass until no trace of moist- ure remains, to add some protochloride of mercury (cor- rosive sublimate), to rub the whole well together, and to place it in a glass tube closed at one end. The tube is then narrowly dravra out a little above the assay, and the mass heated to redness. Protiodide of mercury is formed, which sublimes in yellow or red needles into the narrow tube. This reaction is founded on the property of lime to decompose the protochloride of mercury, but not the protiodide.

Iron. — The reactions of the oxides of iron, see Table

Ii., 13.

§ 83. The colors which iron imparts to the various fluxes are sufficiently characteristic to ascertain its pres- ence in those metallic compounds which contain no easily fusible substances, by simply treating the assay with Bx. on Ch. in the O. Fl. When lead, tin, bismuth, antimony, or zinc are present, the R. Fl. is employed, and directed in such a manner that it principally touches the glass. Thus, the oxidation and consequent saturation of the bead with the oxides of these metals, is to a great extent pre- vented. In either case the glass, while still soft, is re- moved from th& globule and exposed on another place of the Ch. to the R. Fl. Those metals the oxides of which are

o.led by

Special Reactions. 65

easily reduced, are now precipitated, and the characteristic bottle-green color of iron is clearly observable, unless cobalt be present. In this case the glass is again softened with the R. Fl., separated from the precipitated metals, fastened into the hook of a platinum wire, and treated with the O. Fl. until the whole of the iron may be supposed to be converted into sesquioxide. The glass, while hot, will appear green, and blue when cold, if only a trace of iron is present. But when tlie amount of iron is more con- siderable, it will be dark-green while hot and bright-green when cold, the latter color resulting from the mixture of the blue of the cobalt and the yellow of iron. The metals remaining behind on Ch. after the treatment with Ex., and which frequently are only copper and nickel (lead, antimony, and bismuth being volatiliaed), may be treated as shown § 71.

To detect iron in arsenides and sulphides, the assay is well calcined, and the calcined mass treated as above [No. 86 and No. 79].

Or, the substance is pulverized, mixed with test -lead and borax, and fused on coal in the reducing flame until the glass is colored by the easily oxidizable, non-volatile metals present. At first the whole is covered with the R. Fl., but as soon as the borax has united to one globule, the flame is directed upon this alone, allowing the air free access to the fusing metal. When the fusion is complete, the glass is quickly raised with the forceps from the fluid lead, and, after being treated alone on coal in the R. Fl., to reduce any oxide of lead in it, is tested on platinum wire in the O. Fl. If too dark, it is diluted with borax until it is transparent. After separating the bead by means of boracic acid, the other metals combined with it can easily be recognized by the glass fluxes.

o.led by

66 Special Reactions.

Compounds which fuse easily alone on coal can be treated in the K.. F!. with borax, omitting the test-lead. For example, a small trace of iron may be found in galen- ite, especially if the glass is further treated with tin.

I 84. The oxides of iron, when associated with a large quantity of manganese [No., 84 and No. 69], color the Ex. bea4 on platinum wire in the O. Ft. red. To show the presence of iron the bead is removed from the wire, placed on Ch., and treated with tin in the R. Fl. The vitriol- green color of iron will appear in its purity. When asso- ciated with the oxides of manganese and cobalt, a minute quantity of iron cannot very well be detected by means of the blow-pipe alone. When accompanied by the oxides of copper and nickel [No. 78 or 85], the assay is dissolved in Bx, on Ch. in the O. FI. , and the glass treated as shown

§ 85. The presence of chromium prevents any conclu- sive deduction as to the presence of iron from the color of the beads. In such a case the substance [No. 7i] may be mixed with three parts of nitre and one of Sd., and tlie mixture fused in Bjnall portions into the hook of a thick platinum wire. The alkaline chromate is dissolved in water and the residue treated with the fluxes. The pres- ence of the oxides of iron, when associated with the oxides of uranium, cannot be ascertained by means of the blow- pipe alone.

Lead,— The reactions of lead and its compQtinds, see §§ IS. 23. 36, and Table IL, ig.

§ 86. An alloy of lead and zinc [No. go] deposits a Ct. of oxide of lead mixed with oxide of zinc ; the presence of lead is shown by the color of the Ct. and by the aaure- blue tinge which it imparts to the R. F!. (v. § 23).

An alloy of lead and bismuth [No. 49] deposits a Ct.

o.led by

Special Reactions. 6/

somewhat darker than that of pure lead, in which the presence of bismuth may be detected as shown § 59, and the presence of lead by the azure-blue color of the R. Fl.

§ 87. To detect lead in sulphides, the substance is placed on Ch. and treated with the R. Fl. ; the lead is detected by its Ct. An admixture of antimony cannot by this means be ascertained, since the ring of sulphate of lead surrounding that of the oxide bears a striking resemblance to the Ct. formed by oxide of antimony. In this case the pulverized assay [No. 85] is mixed with a sufificient quan- tity of Sd., and treated for a short time with the R. Kl. If no antimony is present a pure yellow Ct. with bluish- white edges is formed ; but in presence of antimony this Ct. is surrounded byanother white one of oxide of anti- mony. The oxide of lead Ct. appears, moreover, darker than usual, resembling that of bismuth, owing probably to the formation of antimonate of lead. If this Ct. is scraped off from the Ch., and treated with S. Ph. as men- tioned § 59, in the case of bismuth, the bead, on cooling, assumes a biack color, whereby, in the absence of bismuth, the presence of antimony is proved, A very small quaii- tity of antimony by this method cannot be found out with certainty, since, by keeping up the blast for some time, the sulphide of sodium begins to vaporize and to coat the Ch. with a ring of sulphate of soda (v. § 30).

§ 88. When sulphide of lead is associated with a con- siderable quantity of sulphide of copper [No. 89], the metallic globule obtained by the process of reduction does not betray, by its physical properties, the presence of lead. But if the alloy is removed from the flux and played upon with a powerful 0. Fl., the greater part of the lead will be volatilized and deposit a Ct.

Chloride of lead before the Blp. first fuses and then

o.led by

68 Special Reactions.

gives two coats ; one of the chloride, white and volatile, and another of the oxide less volatile. It also imparts a blue color to the E.. Fl.

Phosphate of lead alone on coal, fuses to a globule, and affords no coat, or a very slight one.

§89. Lithia. — To detect lithia in silicates which contain only little of it, proceed as follows : The substance [No. 67] is reduced to a line powder and mixed with about two parts of a mixture of one part of fluor-spar with one and a half parts of bisulpliate of potassa ; a few drops of water are added and the whole kneaded into a paste. According to Merlet, it is often necessary to use two parts of the mix- ture with one part of the assay. The mass is fused with the blue cone of the flame into the hook of a platinum wire. If lithia is present the outer flame will appear red. The color is not very intense, aiid verging into violet. The presence of potassa does not prevent the reaction, but makes the flame appear still more violet ; soda makes the reaction uncertain.

If boracic acid be present in the silicate, as in tourma- line, the outer flame at first exhibits a green tinge, but afterwards a wine or less intense red from the lithia.

A mixture of two parts of ignited gypsum, and one part of fluor-spar, is said to be better than the above.

Another method of detecting lithia when mixed with soda is to dip the assay, moistened with hydrochloric acid, into melted wax and then heat it in the blue flame, by which the red color is produced immediately.

Lithia may also be detected by using the indigo prism and Bunsen burner. The assay powder is heated with gypsum in the zone of fusion, and opposite to it some car- bonate of potassa, while both flames are observed through the prism which is passed before the eye. If the assay

o.led by

SPECIAL REACTIONS. 6g

contains lithia, its flame at that point of the prism where the soda flame disappears seems red in comparison with the corn-flower blue potassa flame. As the stratum in- creases in thickness the red lithia flame gradually loses its intensity, while the blue of the potassa fiame passes through violet to red, which at a certain thickness of the stratum is quite similar to the color of the lithia flame.

Manganese. — The reactions of manganese, see Table 11., i6.

I 90. The presence of manganese in any compound substance is readily detected by mixing the pulverized assay [No. 66 or No. 84] with about two or three parts of Sd., and fusing it by means of the O. Fl. on platinum foil. Manganate of soda is formed, which, while hot, is green and transparent, and, on cooling, turns bluish-green and opaque. The reaction is very distinct when as much as one-tenth per cent, of manganese is present. But even the slightest trace may be detected when, instead of Sd., a mixture of one part of nitre with two parts of Sd. is used. Chromium does not prevent the reaction, merely changing the color to yellowish-green. It is only in presence of silica and cobalt that this test is not available, since at a high temperature the silica unites with the soda to silicate of soda, which, in dissolving the oxide of cobalt, produces a blue glass, and thus interferes with the manganese color.

Mercury, — The reactions of mercury and its com- pounds, see §§ II, 17, and Table 11., 17.

§ gr. Mercury is detected in amalgams [No. 47] by the sublimate of metallic mercury which they yield, when in a glass tube closed at one end.

When in combination with sulphur [No. 8i], chlorine [No. 39], iodine, or oxygen-acids, the substance is pre- viously mixed with some anhydrous Sd, or some neutral

o.led by

yo SPECIAL REACTIONS.

oxalate of potassa. The acids, etc., are retained by the soda, and mercury sublimes.

If the quantity of mercury is so small, that the nature of the sublimate cannot with certainty be ascertained, the experiment has to be repeated, a piece of iron wire around which a gold-leaf has been wrapped being at the same time introduced into the tube and held close above the assay. The gold-leaf will turn white, even when the amount of mercuty present is very small.

Nickel. — The reactions of nickel, see Table II., 19.

§ 92. To detect nickel in metallic compounds which are fusible before the Blp , the assay is treated with Bx. on Ch. in the R. FI.; won, cobaU, etc , enter into the flux and may be detected as shown § 69, while the metals the oxides of which are easily reduced remain behind. This operation is repeated until the glass appears no longer colored. The remaining globule is treated with S. Ph. in the O. Fl. We now obtain either the pure color of nickel, or that of nickel mixed with copper, yellowish- green {v, § 72) ; in this case it is tieated on Ch. with tin, whereby the presence of copper ma} be ascertained, the bead becoming opaque and red Bimiuth or antimony prevents the reaction for copper, the bead turning black instead of red. Such compounds m-:t, previous to their treatment with fluxes, be heated on Ch in R. Fl. until all volatile substances are driven off [No 8a].

In arsenides and sulphides nickel is detected by the methods given for cobalt under the same circumstances (v. § 70).

§93. Nitric Acid. — The perfectly dry substance [No. 23] is heated in a matrass with some bisulphate of potassa; orange-yellow vapors of nitrous acid are emitted, even if but a small quantity of a nitrate is present. Or the sub-

o.led by

Special Reactions. ?!

stance may be heated with litharge, free from peroicide of lead, which at first absorbs the nitric acid, but yields it up at a higher temperature. A piece of paper moistened with a solution of protosulphate of iron, free from sesquioxide and acidulated with sulphuric acid, is inserted into the neck of the tube, which should be rather long, and nitrous acid if present will color the paper yellowish to brown.

§ 94. Phosphoric Acid. — A very minute quantity of phosphoric acid may be detected by pulverizing the sub- stance [No. 14], adding a drop of concentrated sulphuric acid, fastening the paste into the hook of a platinum wire, and playing upon it with the blue cone of the flame ; the outer flame will assume a bluish-green color (v. § 35).

Certain nitrogen compounds, as nitric acid, nitrate of ammonia, chloride of ammonium, etc., when fastened into the hook of a platinum wire and touched with the cone of the blue flame, impart to the outer flame a bluish-green color, resembling that caused by phosphoric acid.

g 95. In a substance, containing not less than about five percent, of phosphoric acid, the presence of the latter may be shown by dissolving the assay [No. 68] on Ch. in vitrified boracic acid, and forcing into the glass, when a good fusion is effected, a piece of fine steel wire ; a good R. Fl. is then given. The iron is oxidized at the expense of the phosphoric acid, causing the formation of a borate of the oxide of iron, which fuses at a sufficiently high tem- perature. The bead is then taken from the Ch., envel- oped in a piece of paper, and struck Hghtly with a ham- mer, by which means the phosphide of iron is separated from the surrounding flux. It exists as a metallic-looking button, attractable by the magnet, frangible on the anvil, the fracture having the color of iron. If the substance under assay contained no phosphoric acid, the iron wire

o.led by

Special Reactions.

will keep its form and metallic lustre, excepting at the ends, where it will be oxidized and burnt. The substance to be assayed ought not to contain sulphuric acid, arsenic acid, or any metallic oxides reducible by iron ; but if so, a preliminary test should be made for them.

§ 96. Phosphate of lead, owing to the lead, gives a blue flame, the tip of which has a green color, and also exhibits the peculiarity of crystallizing on cooling after having been fused on Ch ; the crystals have frequently large facets of a pearly lustre.

For very small quantities of phosphoric acid, Bunsen has proposed a test which consists in mixing the substance with two or three times as much soda, and placing the completely dried mixture in the drawn-out part of a small tube, similar to those used in testing for arsenic. The mixture is again heated to remove all moisture, a long bit of sodium inserted into it, and fused with the Blp, When cold, the portion of the tube containing the fused mass is broken off, placed in a porcelain dish, and wet with a few drops of water ; if phosphoric acid was present, the phosphuretted hydrogen formed may be recognized by its

§ 97. Potassa. — The violet color of the flame is suffi- ciently characteristic for potassa (v. § 33). But being altogether prevented, or at least made very indistinct by the addition of a few per cent, of soda or lithia, it can only in a very few cases be made use of. For the detec- tion of potassa in silicates it is almost entirely unavailable, because these compounds almost always contain some soda.

§ gS. If the base of a compound consists essentially of potassa, the following method may be advantageously em- ployed for its detection : Some Ex. to which a little bor- acic acid has been added, is melted into the hook of a

o.led by

Special Reactions. 73

platinum wire, and so much pure protoxide of nickel, free from cobalt, added that the glass on cooling shows a dis- tinct browDish color. A small piece of the substance under examination [No. 15] is made to adhere to the glass and the whole fused together with the O. Fl. If the assay- piece contained no potassa, the color of the glass, after perfect cooling, will have remained unchanged ; but if potassa was present in sufficient quantity, the glass will appear bluish.

The simplest means of detecting potassa in a salt, in which, owing to a greater or less amount of soda, the violet coloration of the flame cannot be recognized, con- sists in viewing the color of the fiame through deep-blue cobalt glass, or a stratum of indigo solution, seepage 213. The presence of potassa is recognized, according to the thickness of the intervening medium, by the violet or poppy-red color, while a very large amount of soda pro- duces a blue color, and a smaller quantity is not percep- tible.

The carbon of organic matter produces the same color as potassa, and if contained in the assay should be re- moved by ignition.

If lithia is present, a thicker stratum of solution or darker glass must be used.

According to Merz, a green glass may be used in some cases with advantage, the lithia flame being invisible through it, while the potassa and baryta flames appear bluish-green, and that of soda orange -yellow.

In testing silicates with the cobalt glass, they should first be heated with pure gypsum in the flame, thus form- ing sulphate of the alkali, which is volatile and colors the flame,

99. Selenium.' — The reactions of selenium are very cha-

o.led by

74 Special Reactions.

racteristic. In iioii -volatile compounds, which do not give the red sublimate mentioned § ii, the selenium is detected by heating a small piece of the substance [No. 87] on Ch. in O. Fi., when the peculiar odor is evolved; if much selenium is present, a Ct. is deposited, v. § 38., Selenites and seienates are treated on Ch, with Sd. in R. Fl., when a reduction takes place and the selenium vaporizes with the characteristic odor.

§ 100. Silica. — Pure silica [No. 54], when treated with Bx. on platinum wire, dissolves slowly to a transparent glass which fuses with difficulty. Treated with S. Ph. in the same manner, only a small quantity is dissolved, the rest floating in the liquid bead as a semi-transparent mass. The behavior to Sd., see § 39. With a little So. Co. it assumes a pale-bluish color, which, on addition of a large quantity of the reagent, turns dark-gray or black ; very thin splinters may be fused by a great heat to a reddish- blue glass.

S loi. Silicates [No. 61], when treated with S. Ph. on platinum wire, are decomposed ; the bases unite with the free phosphoric acid to a transparent glass, in which the silica may be seen floating as a gelatinous, cloudy mass. The bead ought to be carefully observed while hot, since many silicates form a glass which on cooling opalizes or becomes opaque, when, of course, the phenomenon can no longer be seen. The experiment is best performed with a small splinter of the substance under examination, and only when this does not appear to be affected by the flux, the finely pulverized substance should be used. If but a very small quantity of silica is present, the glass will appear perfectly transparent. Its presence in this case cannot be detected by means of the Blp.

§ ro2. Silicates containing at least so much silica that

o.led by

Special Reactions. 7$

the quantity of oxygea in the acid is twice that of the oxygen in the base, dissolve, when treated with Sd. on Ch,, with eifervescence to a transparent glass, which re- mains so when cold When less silica is present decom- position TJbo taheb place, hut the glass turns Opaque on cooling, the amount of silicate of soda which is formed not being sufficient to dissolve the eliminated bases.

Silver — Ihe reactions of silver, see § 27, and Table IL, ,,.

I 103. When in combination with metals which are volatile at a high temperature, ex. gr, bismuth, lead, zinc, antimony, the substance is heated alone on Ch., when, after volatilization of these metals by long blowing, a button of pure silver remains behind, and a reddish Ct. is deposited on the Ch. If associated with much lead or bismuth, these metals are best removed by cupellation, a process which is executed in the following manner : Finely pulverized bone-ash is mixed with a minute quantity of soda, and made with a little water into a stiff paste ; a hole is now bored into the Ch., filled with the paste, and its surface smoothed and made slightly concave by pressing on it with the pestle of the little agate mortar. The mass is then dried by the flame of a gas or spirit lamp. On this little cupel the assay [No. 51] is placed, and heated with the O. Fl. until the whole of the lead or bismuth is oxid- ized and absorbed by the cupel. The silver, or if gold is present, the alloy of silver and gold, remains as a bright metallic button on the cupel.

§ 104. When combined with metals which are not vola- tile, but which are more easily oxidized than silver, the presence of this metal may in some cases be detected by simply treating tlie alloy with Bx. or S. Ph. on Ch. Cop- per, nickel, cobalt, etc., are oxidized and their oxides

o.led by

76 Special Reactions.

dissolved by the flux, while silver remains behind with a bright metallic surface. But when these metais are pres- ent to a considerable extent, another course has to be pur- sued, a course which may always be taken when a sub- stance is to be assayed for silver, or silver and gold.

§ 105. The assay-piece [No. 86] is reduced to a fine powder, mixed with vitrified Bx. and metallic lead (the quantities of which altogether depend upon the nature of the substance, and for which, therefore, no general rule can be given), and the mass placed in a cylindrical hole of the Ch. A powerful R. Fl. is given until the metals have united to a button, and the slag appears free from metallic globules. The flame is now converted into an O. Fl. and directed principally upon the button. Sulphur, arsenic, antimony, and other very volatile substances, are volatihzed; iron, tin, cobalt, and a little copper and nickel become oxidized and are absorbed by the flux ; sil- ver and gold and the greater part of the copper and nickel remain with the lead (and bismuth, if present). When all volatile substances are driven off, the lead begins to become oxidized and the button assumes a rotary motion ; at this period the blast is discontinued, the assay is allowed to cool, and when perfectly cold the lead button is sepa- rated from the glass by some slight strokes with a hammer. It is now placed on a cupel of bone-ash and treated with the O. Fl. until it again assumes a rotatory motion. If much copper or nickel is present, the globule becomes covered with a thick infusible crust, which prevents the aimed-at oxidation ; in this case another small piece of pure lead has to be added. The blast is kept up until the whole of the lead and other foreign metals, viz., copper and nickel, are oxidized ; this is indicated by the cessa- tion of the rotatory movement, if only little silver is pres-

orted by GoOglc

Special Reactions. 77

ent, or by the appearance of all the tints of the rainbow over the whole surface of the button, if the ore was very rich in silver ; after a few moments it takes the look of pure silver. The oxides of lead, copper, etc., are absorbed by the bone-ash, and pure silver, or an alloy of silver with other coble metals, remains behind ; the button may be tested for gold, etc., after the method given in § 79.

The chloride of silver can be reduced on coal with soda.

§ 106. Sulphur. — The presence of sulphur in sulphides may in many cases be detected by heating in a glass tube (v. gg II, 14), or on Ch. with the O. Fl.

§ 107. A very delicate test for the presence of sulphur, in whatever combination it may be contained in the sub- stance, and which possesses moreover the advantage over all other methods of being very easily performed, is to mix the pulverized assay [No. 4] with some pure Sd., or, better still, with a mixture of two parts of Sd., perfectly free from sulphates, and one of Bx., and to treat it on Ch. with the R. Fl. The fused mass is removed from the Ch., powdered, the powder placed on a silver foil or a bright silver coin, and a drop of water added. If the substance under examination contained any sulphur, a black spot will be formed on the silver foil, owing to the formation of sulphide of silver from the decomposition of the sul- phide of sodium, which, in its turn, resulted from the de- composition of the sulphide or sulpliate, or other sulphur- compound of the assay-piece, under the influence of Sd., Ch., and a high temperature. Selenium shows the same reaction, but is readily recognized by the peculiar odor which it emits when heated on Ch. alone.

Dana suggests the following test. Fuse the substance with soda in the R. Fl. , moisten with a drop of water in a watch glass, and add a bit of nitro-prusside of sodium. If

o.led by

78 Special Reactions.

sulphur in any form is present a purple color will be pro- duced.

A dilute solution of molybdate of ammonia with an excess of hydrochloric acid is colored fine blue by a small quantity of sulphuretted hydrogen or sulphides dissolved in water.

To decide whether the reactions obtained in the experi- ments above were owing to the presence of a sulphide or to that of a sulphate, the finely-pulverized substance [No. 79] is fused in a small platinum spoon with some hydrate of potassa. The spoon with the contents is then placed in a vessel containing some water, and a piece of silver foil inserted into the liquid. If the silver remains per- fectly bright, a sulphate was present ; if it turns black, a sulphide. The absence of substances which might exer- cise a reducing influence is required.

§108. Sulphuric and Sulphurous Acids. — When the bases of the salts do not color the beads, sulphuric acid can be detected by forming with soda and silica on coal a bead in the R. Fl. which is clear and colorless, which is fused with a little of the salt in the R. Fl., and then ob- serving the color. Sulphuric acid gives a yellow to a dark-red color, according to the amount present. If the bases produce color, the salt must first be decomposed by mixing it with twice its amount of soda, igniting it in the R. Fl. on platinum wire or foil, dissolving the sulphate of soda formed in a few drops of water, evaporating the clear solution to dryness on platinum foil or in a small porcelain dish, and testing the salt as above with silicate of soda.

Or mix the substance to be tested with two or three times its weight of soda, or neutral oxalate of potassa (quite free from sulphate), and fuse in the R. Fl. on coal. The mass, with a piece of the coal into which it has sunk, is placed

o.led by

SPECIAL SEACTIONS. "jg

on a bright silver foil and moistened with water, when a brown, or black stain will appear. The fused mass may also be covered with hydrochloric acid in a matrass, and the presence of sulphuretted hydrogen tested by inserting a strip of filter paper, moistened with a solution of acetate of lead, into the mouth of the matrass. The paper will be colored brown or black.

§ 109. Tellurium. — The presence of tellurium in min- eral substances is detected by the tests given §§ ii, i5, 29. In presence of lead or bismuth, the reactions in the open tubes and on Ch. are not quite pure. In this case we may subject the assay to the following treatment : The substance is mixed with some Sd. and charcoal-powder, the mixture introduced into a glass tube closed at one end, and heated to fusion; after cooling, a few drops of hot water are poured into the tube ; if tellurium was present, telluride of sodium has been formed, which dissolves in hot water with a purplish-red color. This test is applica- ble to show the presence of tellurium in a great many com- pounds, even when it occurs in the oxidized state.

Natural tellurium compounds, when gently heated in a matrass with an excess of sulphuric acid, impart to it a purple or hyacinth-red color, which disappears on adding water, while a blackish-gray precipitate is formed. When a mineral containing tellurium is treated on coal it gener- ally yields a white, tellurous acid coat, with a reddish- yellow border, which disappears under the K. Fl., impart- ing to the flame a green, or, in presence of selenium, a bluish-green tinge. The horse-radish odor would be a certain indication of selenium.

If the mineral contains lead or bismuth, and is treated alone on coal for only a few moments, no pure tellurous M.cid coat is obtained, but 4 mixture of this with oxide of

o.led by

8o SPECIAL REACTIONS.

lead or bismuth is liable to be deposited. TJiis difficulty can be remedied by mixing the powdered assay with an equal volume of vitrified boracic acid and treating it in the R, Fl. The oxide of lead or bismuth is dissolved in the boracic acid, notwithstanding the reducing flame, and yields ilo4cpat, while the tellurium alone volatilizes and coats the coal. When much selenium is also present a portion of it is deposited on the coal, and then the tellu- rous acid coat is less distinct. In such cases the mineral must also be tested' in the open tube.

Tin. — The reai:tions of tin and its compounds, see §§ 13, zd, 45, and Table 11, 30.

§ 1 10. The presence of tin is indicated by its Ct. when the substance [No. 13], alone or mixed with Sd., is ex- posed to the R. Fl. on Ch.

When the substance under examination is an alloy, a little Bx. is conveniently added, which absorbs the oxide of tin in a measure as it is formed, and allows the pres- ence of those metals which are more volatile, ex. gr. anti- mony, lead, bismuth, to be recognized by their yellow coatings. In case of doubt as td*the presence of lead or bismuth, the coat is carefully scraped off, dissolved in S, Ph. on platinum wire, Mid the bead treated on coal with tih- Bismuth is shown by the gray or black appearance of rhe cold bead. Arsenic is detected by its odor, and iron by the color which the Bx. bead 'assumes when re- fuSeon platinum wire in the O. Fl. '

To detect copper in tin or its alloy, theJsay [No. 53] IS fused with a fiux consisting Of one hundred parts of Sd., fifty of vitriiied Bx., and thirty of sUica. The flame is" so directed that the metallic globule assumes a igtatory motion. When in this state the glass is kept coveras much as possible with the O, Fl., care being taken tiio globule

o.led by

Special Reactions. 8 1

is at one side in contact witli|;he glass, and at t!ie otlier witii tlie Cli. Tlie tin becailie&twxidized, and the oxide, in a measure as it is formed, absorbeS tlie flux ; the j-e- maining button is copper, pure,iaa:--with a small qutity of tin, and may be readily the usual fluxes.

To detect a little copper iigft-t is trealed wiEh' succes- sive portions of S. Ph. on c0£P:.the~O.-Fl. tSUJl nearly all the tin is separated and the faaining. bpttdlfparts a bluish-green color to the glass, when a bit of pure tin. is added and the glass treated a short lime in the R. FL ; on cooling, the bead becomes red.

Tin, when present in alloys, is almost always detectqj on fusing them upon coal ; the globile is crusfed with oxide, which can be removed with some diiEculty after adding borax.

Sulphides containing tin, but forming ncoat gfrfiside of tin near the assay, when treated alone 'cflal, must be roasted and treated in the R. Fl. with soda and borax, when metallic tin is obtained, which may be tested alone on coal. If other reducible metals are present they form an alloy, in which the other metals can be recognized by means of the fluxes.

In metallic oxides, or substances generally'composed of oxides, tin may be detected by a reduction assay on coal' with soda or neutrtil oxalate of potassa. It is sometimes necessary to add borax to aorb the iron.

§ 111. Titanium. — Titanic acid, when forming thepfin- cipal constituent of any mineral substance, is easily de- tected by its behavior with the fluxes, v. Table II,, 31 ; but when in combination with bases these reactions are not always clearly perceptible, being frequently obscured by the predominating reaction of the base. In such cases we may subject the assay to the following treatment, by

o.led by

82 Special Meactions.

which even very small qioantities of titanic acid will be- come apparent : the substance [No. 65] is reduced to a very fine powder, mixed with from six to eight parts of bisulphate of potassa, and fused in a platinum spoon at a low red-heat ; the fused mass is dissolved in a porcelain vessel in the smallest possible quantity of water, aided by heat. If concentrated, may be heated to boiling. There remains an insoluble residue, which is allowed to settle; the clear liquid is poured off into a larger vessel, mixed with a few drops of nitric acid and at least six volumes of water, and heated to ebullition. If the substance under examination contained any titanium, a white precipitate of titanic acid forms on boiling. If the solution is not acidified with nitric acid before boiling, a yellow, ferru- ginous titanic acid is obtained when the substance contains iron. The precipitate is collected on a filter, washed with water, acidulated with nitric acid, and tested with S. Ph. either on platinum wire or on coal. If the amount of titanic acid is so small that it does not give in the R. Fl. to the S. Ph. the violet color of sesquioxide of titanium, it is only necessary to add a little sesquioxide of iron when the assay is upon a wire, or a small piece of iron wire when on coal, and to fuse the glass for a short time wih the R. Fl, ; it appears yellowish while hot and brownish-red when

§ 112. Uranium. — The presence of this metal is easily recognized, in substances which contain no other coloring constituents, by the reactions given Table II., 'y, the most characteristic test is that with S. Ph. In presence of much iron this reaction becomes indistinct ; we may then operate Ln the following manner : the finely-pulver- ized substance [No. 70] is fused with bisulphate of potassa, the fused mass dissolved in water, mixed with carbonate

o.led by

Special Reactions.

byfil

d h fi

!

d

b 11 lion.

m

asp y 11

P

P

1 -own

1 h g

h 1 fl

f pure

d 1 d fa} m g 1 1 1 q g eated

wl fcabnaf n dhp ocess con-

d d b

Z —11 f d po d , see

g§ 12, 25, 45, and Table U., 35.

§ 113. A small amount of zinc, when associated with considerable quantities of lead, or bismuth, or antimony, or tin, cannot always with certainty be ascertained by means of the Blp,

If the substance under examination contains the zinc as oxide [No. 36], or but a small quantity of sulphide, it is mixed with Sd and treated on Ch in R. Fl, Substances consisting essentially of sulphide of zinc may be thus treated without the addition of Sd , and such as contain, besides oxide of zinc, other metallic oxides, are conve- niently mixed with some Sd to which about one-half of its weight of Bx has been added A ring of oxide of zinc is deposited on the Ch When lead is present [No. 50] the Ct IS frequently not pure, being mixed with the Ct. of lead. In this case it is moistened with some So. Co. and heated again with the O. Ft. The oxide of lead is reduced by the red-hot Ch. and volatilized, while the oxide of zinc remains behind with a green color (v. § 45).

o.led by

84 Special Reactions.

In the presence of much antimony a little zinc can only be found with difficulty before the Blp., for the adds of antimony formed will have a greeii color and cannot be driven off with the O. Fl. In many compounds, however, all of the antimony may be volatilized with the O. Fl. and the zinc then treated with the So. Co.

If tin is present the zinc cannot be recognized by the coating on coal, as its oxide assumes a bluish-green color with So. Co.

o.led by

Chapter Iv.

Characteristics of the most important Ores: their be- havior before the Blow-Pipe, and to Solvents.

§ 114. Of the physical properties of the minerals which are treated of in this chapter, only those are enumerated which serve best to discriminate the different ores from each other. For a more detailed description, the student mmt refer to Dana's and other works on mineralogy. Among the distinguishing characters of minerals, their crystalline form, hardness, and specific gravity stand foremost. The latter cannot be ascertained without a good balance, and will, for this reason, be of much less use to the practical man than the determination of hardness, an operation which may be performed in a few moments. A set of minerals, representing the scale of hardness, being not always at hand, it will be useful to give a series of substi- tutes for them, as arranged by Mr. Chapman :

1. Yields easily to the nail.

2. Yields with difficulty to the nail, or merely receives an impression from it. Does not scratch a copper cojn.

3. Scratches a copper coin ; but is also scratched by it, being of about the same degree of hardness.

4. Not scratched by a copper coin ; does not scratch glass.

5. Scratches glass, though with difficnity, leaving its powder upon it. Yields readily to the knife.

6. Scratches glass easily. Yields with difficulty to the knife.

8 8S

o.led by

86 Characteristics Of Ores.

Does not yield to the knife. Yields to the edge of a file, though with difficulty.

8, 9, 10. Harder than flint.

The scale of hardness, as introduced by Mohs, and en- larged by Breithaupt, is as follows ;

1. Talc; common laminated light-green variety.

2. Gypsum ; crystalline variety.

3. Catcite ; transparent variety,

4. Fluorite ; crystalline variety. S- Apatite; transparent variety.

6. Orthociase; white cleavable variety.

;, Quartz; transparent.

8. Topaz ; transparent.

9. Corundum ; cleavable varieties.

10. Diamond.

To test the hardness of a mineral we may proceed in. two different manners : firstly, by attempting to scratch it with the minerals enumerated in the scale, successively; or, secondly, by abrasion with a file. If the file abrades the mineral under trial with the same ease as No. 4, and produces an equal depth of abrasion with the same force, its hardness is said to be 4. If with more facility than 4, but less than 5, the hardness may be 4.3 or 4.5. Several successive trials should be made to obtain certain results ; and, when practicable, both methods should be em- ployed.

For scale of fusibility, see Chap. VI.

OEES OF AHTIMOirr.

§ 115. Stibnite [Gray Antimony]. — Sb'S". H 3.

4-S- Ji-SSb. Orthorhombic. Of lead-gray color

and streak, and metallic lustre. Usually of columnar

structure, consisting of a vast number of needle-shaped

o.led by

Characteristics Of Ores. &J

crystals, sometimes side by side, sometimes divergent. Very brittle.

It fuses readily in the flame of a candle. In a matrass, sometimes yields a slight sublimate of sulphur ; on increas- ing the heat by application of the Blp, flame, a sublimate is produced which after cooling is brownish-red, and which consists of a mixture of tersulphide of antimony with antimonous acid. In an open glass tube, emits sul- phurous acid and antimonial fimies. On Ch. it is vola- tilized, covering the Ch. with oxide of antimony which, when touched with the R. Fl., disappears with a pale greenish-blue tinge.

When pure, wholly soluble in heated hydrochloric acid with evolution of sulphuretted hydrogen ; usually a residue of chloride of lead is left. Partly decomposed by caustic potassa; the solution, when mixed with an acid, affords a yeilowish-red precipitate.

§ 116. Bertlllerite. — Composition variable, sometimes FeS + SbS'. 57Sb, i3Fe. H=2-3. G=4-4-3- Orthorhombic. Metallic lustre, less splendent than gray antimony; color, dark steel-gray; surface often covered with iridescent spots.

Heated in a matrass, fuses and yields a slight ubl nate of sulphur; on application of a strong heat, a bla k ubl mate of sulphide of antimony is formed, wh 1 o oul ing, becomes brownish-red. In an open glass tube behaves like the preceding ore. In Ch. fuses easily and coats the charcoal with oxide of antimony ; there remains, finally, a black slag, which is attracted by the magnet and gives with fluxes the iron reaction.

Soluble in hydrochloric acid.

g in. Eermesite [Red Antimony]. — 2 SbS' -f- SbO. 75.3Sb. I — 1.5. G 4.5 — 4.6. Monoclinic.

o.led by

88 Characteristics Of Ores.

Usually in tufts of capillary crystals of cherry-red color, with adamantine lustre. Streak, brownish-red.

In a matrass, fuses readily and yields a slight yellowish- red sublimate ; with strong heat, boils and gives a black sublimate, which when cold is brownish-red. In an open tube and on Ch. behaves like gray antimony.

It dissolves in hydrochloric acid with evolution of sul- phuretted hydrogen. The powdered mineral when treated with caustic potassa assumes an ochre-yellow color and dissolves completely.

Ores Op Arsenic.

§ 118. Native Arsenic. — As, with traces of Sb., Ag., Fe., Co.,andNi. 11=3.5. Rhombohedral. Of dull metallic lustre ; color and streak, tin-white, tarnishing on exposure to air to dark-gray.

Heated in a matrass, sublimes ; on Ch. behaves like pure arsenic. In both cases, sometimes, a residue is left which, when treated with fluxes, exhibits the reactions of iron, cobalt, and nickel. (See § 83.)

§119. Realgar. -AsS. 70.1AS. H=i.s_z. G 3.4 — 3.6. Monoclinic. Usually of bright-red, some- times of orange-yello\y color, and resinous lustre. Sectile. Streak, orange.

In a matrass, fuses, boils, and finally sublimes ; the sub- limate after cooling is red and transparent. In an open glass tube, when carefully heated, yields a sublimate of arsenous oxide, sulphurous acid escaping. On Ch. fuses readily and bums with a yellowish- white flame, emitting grayish-white fumes which possess the peculiar alliaceous odor. Subjected to the treatment described § 55, a sub- limate of metallic arsenic is obtained.

Not easily aifected by acids j but aqua regia dissolves it

o.led by

Characteristics Of Ores. 89

with continued digestion, part of the sulphur being pre- cipitated. A heated solution of caustic potassa decom- poses it, leaving a brownish-black powder (As) undis- solved.

§120. Oi-piment— As'S'. As6i. H=i.5— z. 0=3.4- Orthorhombic. A foliaceous mineral of lemon- yellow color and streak, and resinous or pearly lustre. Sectile.

Before the Blp. behaves like the preceding, with this difference, that the sublimate, after cooling, is dark-yellow and transparent.

Soluble in aqua regia, caustic potassa, and ammonia.

§121. Arsenollte [White Arsenic].— AsO'. H=i.s. 3.1. Isometric. Occurs usually in minute capillary crystals of a white color and streak, and vitreous or silky lustre.

Before the Blp. it behaves like pure arsenous oxide (v. |§ii, 15, TablelL, 2).

Slightly soluble in hot water ; more so in water acidu- lated with hydrochloric acid.

ORES OF BISMXfTH.

§122. NativeBisimitli. — Bi:H= 2 — 2.5. 9.7. Hexagonal. Color and streak silver white, tinged with red. Lustre metallic. Brittle when cold ; but when hot may be laminated. Occurs foliated, granular, and arbo- rescent; occasionally crystallized.

Before the Blp. it behaves like pure bismuth (v. §§ 17,

Readily dissolved by nitric acid ; the solution is precip- itated by water.

§ 123. Tetradymite [Telluric Bismuth].— Bi. and Te. in variable proportions. 53 — 6iBi, 34 — 48Te. H=i.5 — 3. (5 7.28.4. Hexagonal. Of pale steel-gray color,

o.led by

go CHARACTERISTICS OF ORES.

and high metallic lustre. Occurs usually in tabular crys- tals or foliated masses; the lamiiiEe are elastic. It soils paper.

In an open glass tube it fuses readily, emitting a white smoke which partly condenses, coating the tube near the assay-piece with a white powder, intermixed with red spots ; on directing the flame on this Ct. it fuses to color- less drops (TcO'), while the red sublimate (Se) disappears. On Ch. fuses instantly to a metallic globule which, when touched with the inner flame, imparts a bluish-green color to the outer one, sometimes gives out selenium vapors, and deposits, close to the assay-piece, a dark orange Ct. surrounded at a greater distance by a white Ct.

Soluble in nitric acid.

§ 124. Bismutite. — 3 (BiO'.CO + HO) + BiO.HO. go.iBiO'. H 4 — 4.5. G 6.g, Streak usually of a white or light -greenish color; lustre vitreous; in acicular crystallizations.

In a matrass, decrepitates, yields a little water, and turns gray. On Ch. fuses very readily and is reduced, with effervescence, to a metallic globule, covering the Ch. with a Ct. of oxide of bismuth. If the blast is kept up for some time the whole of the bismuth is volatilized, and there remains a scoriaceous mass which in the R. Fl. may be fused to a globule, and which with fluxes gives the in- dications of copper and iron. With Sd. it usually gives the sulphur reaction 107).

Dissolves in hydrochloric acid with effervescence ; the solution has a yellow color.

§125. BismnthinitB.— BiS'. Si.ssBi. H 2 — 2.5.

G 6.4 — fi-SS- Orthorhombic. In acicular crystals or massive ; of metallic lustre, and lead-gray color, with a yellowish or iridescent tarnish. Streak, shiny. In a matrass, fuses and yields a slight sublimate of sul-

o.led by

Characteristics Of Ores. 9I

phur. Carefully heated in an open tube, it fuses and yields sulphurous acid and a coat of sulphate of bismuth ; the latter may be fused, by application of the Blp. flame, to brown drops which, when cold, appear yellow and opaque. On Ch. fuses and boils, throwing out small drops in a state of incandescence, and deposits a Ct. of oxide of bismuth.

Soluble in nitric acid with deposition of sulphur. The solution gives a, white precipitate with water.

CMviatite.— aCuS, 3BiS',+ 4 (Pb% Bi'S'). 62. 9B;. Decomposed with nitric acid, with separation of sulphate

§ 1S6. Bismite [Bismuth Ochre]. — BiO', containing minute quantities of Fe'O', CuO, and AsO'. 89.6561. G 4.36. Occurs usually pulverulent or earthy. Streak, straw-colored.

Before the Blp. it behaves like pure oxide of bismuth. Soluble in nitric acid,

Ores Of Chromium.

%\Ti. Chromite [Chromic Iron].— (FeO, CrO, MgO) + (C'0 ATO'). 68Cr=0'. H 5.5. G 4.3 — 46. Isometric. Occurs usually massive ; of iron - black or brownish-black color, with a shining and somewhat metallic lustre. Some varieties are magnetic. Streak, brown.

Heated in a matrass, remains unchanged. Infusible in the forceps. After having been exposed to the R. Fl. it follows the magnet. In Bx. and S. Ph. slowly, but com- pletely, soluble to a transparent glass, which is beautiful green after cooling. Mixed with Sd. and nitre, and heated on platinum-foil, the mass fiises and becomes yellow. With Sd. on Ch. in R. Fl. it affords metallic iron.

Concentrated acids affect it but little, even when finely

o.led by

92 CHAS Ad ERISTICS OF ORES.

pulverized ; they dissolve only a little iron. Fused witli caustic potassa, chromate of potassa is formed.

Oees Of Cobalt.

§ 128. Smaltite [Smaltine]. — (Co, Fe, Ni) As'. H 3.5 — 6. G 6.4 — 7.2. Isometric. Of tin-white or steel-gray color, and metallic lustre. Streak, dark brown.

In a matrass, usually yields, when heated to redness, a sublimate of meta,Uic arsenic In an open glass tube, affords a copious sublimate of crjstalhzed arsenous oxide, and sometimes emits sulphurous acid On Ch. it fuses readily, with emission of copious arsenical fumes, to a grayish black magnetic globule which, with the fluxes, gives the mdicitions of iron, cobalt, and nickel.

With nitric acid it gives a pink solution, arsenous oxide being deposited.

§ 129. Cohaltite [Cobaltine]. — CoS' -f- CoAs'. 3S.sCo, 45.zAs. H 5.g. 0=6 — 6.3, Isometric. Ofsilver- white and sometimes reddish color, and metallic lustre. Streak, gray.

Unchanged in the matrass. In an open glass tube, yields a sublimate of arsenous oxide and vapors of sulphur- ous acid. On Ch. emits copious arsenical and sulphur fumes and fases to a dull black metallic globule, which is attracted by the magnet, and which when treated with fluxes gives the indications of cobalt and iron, and some- times also those of nickel.

Dissolves in heated nitric acid, arsenous oxide being deposited.

i 130. Lianjeite [Cobalt Pyrites].— 2CoS-|-CoSl 58C0. H=5.5. 4.8 — 5. Isometric. Of a more or less bright steel-gi-ay color, and metallic lustre. Crystallizes in regular octahedrons. Streak, dark gray.

o.led by

Characteristics Of Ores. 93

In an open glass tube, sulphurous acid is abundantly evolved, and sometimes a light sublimate of arsenous oxide formed. On Ch. small pieces of the mineral readily fuse to a globule which when cold is covered with a black rough crust, and which is attracted by the magnet. The pulverized mineral, after having been well calcined, dis- solves in Bx. in O. Fl. to a blue transparent bead. In a highly saturated bead of this kind, when treated on Ch. with R. Fl., particles of metallic nickel may be seen floating about.

Soluble in nitric acid, excepting the sulphur.

§ 131. Erythrite [Cobalt Bloom] — -CoO. AsO'+SHO. 37.S5CoO, 38,43AsO H - 5 -2.9. Mono-

clinic. Usually of crims x color ; when

crystallized, of pearly lust tr q dull and earthy,

forming incrustations. St k p d

Heated in a matrass, loses w nd he color changes

to blue or green. A snia p d to the inner

flame fuses and colors the fl p blue. On Ch.

in R. Fl. emits arsenical n d s to a dark-gray

globule of arsenide of cob h h w h fluxes gives the

pure cobalt-reactions.

Acids dissolve it readil red liquid ; the

solution in concentrated h d h d appears blue

while hot. The pulverized m n ra p tly decomposed by caustic potassa ; the powd a bluish-gray color

and the solution is sapphire -blue.

Var, A. Roselite. — H 3. Cleavage distinct and brilliant, lustre vitreous ; color, deep rose-red.

Var. B. Laveudulan, — H 2.5-3. 3, Amor- phous, with a greasy lustre ; color lavender-blue. Streak, pale blue.

Heated in a matrass, gives out water. In the forceps

o.led by

94 Characteristics Of Ores..

fuses easily and colors the outer flame deep-blue"; the fused mass becomes crystalline on cooling. On Ch. in R. n. it fuses with emission of arsenical futnes. With fluxes, gives the reactions of Co., Ni., and Cu. (see § 92.)

§ 132. Asbolite [Earthy Cobalt], —It is a variety of Wad (see § 184), containing sometimes a considerable quantity of oxide of cobalt (32 per cent.), in combination with silicic or arsenic acid.

With Bx. in O. Fl. gives a dark-violet glass, which in the E-. Fl. becomes blue. The S. Ph. bead when treated on Ch. with metallic tin frequently exhibits the copper- reaction. With Sd. on platinum-foil it shows the presence of manganese.

Soluble in hydrochloric acid with evolution of chlorine ; the solution is usually blue, and on addition of water be- comes red.

§ 133. Remingtonite. — It occurs as rose-colored in- crustation, soft and earthy; opaque- Streak, pale rose- colored.

It is a hydrous carbonate of cobalt. CoO.CO=,HO. Soluble in hydrochloric acid with effervescence, giving a green solution, the color due to iron. Gives the cobalt- reaction with boraK.

It sometimes resembles kermesite, also some varieties of cuprite, but can be easily distinguished from these by the Blp.

Ores Of Copper.

§134. Native Copper. — Pure Copper. 11 2.5 — 3. G S.9. Isometric. Of metallic lustre and copper-red color. Occurs usually massive or arborescent,

It fuses on Ch. to a globule which, if the heat is suffi- ciently high, assumes a bright bluish-green surface ; on

o.led by

Characteristics Of Ores. 95

cooling it becomes covered with a crust of black oxide. With the fluxes it gives the usual indications of copper.

It dissolves readily in nitric acid.

§ 135. Clialcopyrite [Copper Pyrites]. — Cu'S + Fo'S'. 34.6CU, 30.5Fe. H 3.g — 4. 4.1—4.3. Tetrag- onal. Of a brass-yellow color and metallic lustre ; on exposure to moist air it becomes iridescent on its surface. It occurs crystallized, but usually massive. It is easily scratched with a knife, giving a green isli-black powder.

Heated in a matrass, decrepitates and yields sometimes a faint sublimate of sulphur, assuming at the same time a darker color or becoming iridescent. HeaJed in an open glass tube, sulphurous acid is given out abundantly. On Ch. when heated it blackens, but becomes red on cooling ; with continued heat it fuses to a black globule, which is attracted by the magnet ; this globule is brittle, and red- dish-gray in the fracture. The pulverized mineral, after roasting, gives with fluxes the indications of iron and cop- per. With Sd. on Ch. it is reduced ;' the metals are ob- tained in separate masses. Moistened with hydrochloric acid it colors the flame green even previous to fusion.

It dissolves in nitric acid, but more readily in aqua regia, leaving a residue of sulphur,

§136. Boniite[Purple Copper]. — (FeCu')S. 50-67CU, 7-iSFe. H 3. G 4.4 — 5, Isometric. When crys- talh'ne it usually takes the cubical form, and is of a pale- yellowish color ; when massive, its color is copper-red to reddish-brown ; it speedily tarnishes, assuming various hues, mostly purple, blue, and reddish. When scratched with a knife it gives a grayish powder. Streak, black.

Before the Blp, it shows pretty much the same behavior as copper pyrites.

Concentrated nitric acid dissolves it, leaving the greater part of the sulphur behind.

o.led by

96 Characteristics Of Ores.

U37. Chalcocite [Copper Glance]. — Cu'S. jg.SCu. 2,5 — 3. 5.5 — 5.8. Orthorhombic. Ofablack- ish lead-gray color, often with a bluish or greenish tint on its surface. Occurs usually in compact masses, very often shining. Streak, black.

Heated in a matras.s, nothing volatile is given out. In an open tube, sulphurous acid is evolved. On Ch. readily fuses to a globule, which boils and emits glowing drops, sulphurous acid escaping abundantly ; the outer flame is at tlie same time colored blue. With Sd. on Ch. it yields a globule of metallic copper.

In heated nitric acid it dissolves, leaving a residue of sulphur.

§ 138. TetraJiedrite [Gray Copper]. — 4CuS + Sb', or general formula 4 (Cu', Fe, Zn, Ag, Hg) + (Sb, As, Bi)''S. H=3 — 4.5. 0=4.5 — S' Isometric; tetrahedral. Color and streak between steel-gray and iron-black.

Heated in a matrass, fuses and finally yields a dark-red sublimate of teisulphide of antimony with antimonous oxide. In an open glass tube, fuses and gives thick fumes of antimony (and arsenous oxide) and sulphurous acid ; mercury when present condenses in the upper part of the tube, forming a metallic mirror. On Ch. it fuses readily to a globule, emitting thick white fumes and sulphur vapor ; coatings of antimonous acid and of oxide of zinc are deposited ; the latter is nearer to the assay-piece, and maybe tested with So. Co. [v. § 45]. To detect arsenic, v. §56. To detect mercury, add to the finely-pulverized assay three times its weight of dry Sd. and treat the mixture as directed § 91. The pulverized mineral, after having been well roasted, gives with the fluxes the indications of iron and copper ; with Sd. affords metallic copper and a little iron. To detect silver, treat the mineral with pure lead and Bx. as directed § 105.

o.led by

Characteristics Of Ores. 97

When pulverized, it is decomposed by nitric acid ; the solution has a brownish-green color ; antimonous oxide (and arsenous oxide) and sulphur remain undissolved. Caustic potassa effects partial decomposition ; the sulphide of antimony (and arsenic) enters into solution, and is, on addition of an acid, re-precipitated.

§139. Tennantite. — 4(Ctf, Fe)S, AsS>. 41-51.600. H=3.S — 4- 4.37 — 4.5. Isometric, Always crys- tallized; metallic lustre; color, blackish lead-gray to iron- black. Streak, reddish-gray.

In a matrass, gives a sublimate of tersulphide of arsenic. In an open tube, sulphurous acid and a sublimate of arse- nous acid. On Ch., fuses easily with emission of sulphur and arsenic vapors to a dark-gray globule, which is at- tracted by the magnet. The pulverized mineral gives, after calcination with fluxes, the reaction of iron and copper.

§140. DomeyMte [Arsenical Copper]. — Cu'As. yi.yCti, 28.3AS. 11=3 — 3.5. Reniform, massive, or dissemi- nated; lustre, metallic; color, tin-white to steel-gray; black and soft when impure.

Heated in a outrass, yields a little water and a subli- mate of arsenous acid ; the assay-piece assumes a silver- white color. In an open tube, affords a crystalline subli- mate of arsenous acid. On Ch., fuses easily with emission of a strong alliaceous odor, to a reddish metallic mass, which gives the copper reactions.

Readily soluble in nitric acid ; decomposed by hydro- chloric acid, metallic arsenic remaining undissolved.

Binnite', fCu'S+AsS'; Enargite, 3CuS + As'S; Algo- donlte, Cu'As=; WMtneyite, Cu'As'.

§141. Atacamite. — 3CUO.HO + CnCLHO. 14.3CU. H=3 — 3.5. G=4 — 4.3. Orthorhorabic. Occurs crys-

o.led by

98 Characteristics Of Oses.

talline, or massive lamellar; color and streak, various shades of bright-green, sometimes blackish-green. Lustre vitreous.

Heated in a matrass, gives out water and a gray subli- mate, which, on cooling, becomes grayish-white ; the water shows acid reaction. On Ch. fuses readily, colors the outer flame azure-blue, and is finally reduced to a globule of metallic copper ; two coatings are deposited on the Ch. , the one grayish- white, and the other brownish, which, on being played upon with the R. Fl., change their place with an azure-blue tinge.

Easily soluble in acids.

§142. Cnprite [Red Copper]. — Cu'O. SS.SCu. H 3.5 — 4. 5.8 — 6. Isometric. Usually of a very intense, deep-red color, occasionally crimson-red ; exceed- ingly friable. Streak, red to brownish.

Heated in the pincers, fuses and colors the outer flame emerald-green ; moistened with hydrochloric acid and treated in the same manner, the color is azure-blue. On Ch. it blackens, then fuses quietly, and finally yields a globule of metallic copper which, on cooling, becomes covered with a coating of black oxide.

Dissolves readily in nitric acid. It is also soluble in ammonia : the solution is colorless when the access of air is prevented ; on exposure to air it turns blue.

§143. MalaeMta— 2CuO.CO' + HO. S7,4Cu. 3.5 — 5. 0=3.7 — 4- MonocUnic. Occurs usually in the shape of mammillated concretions; the interior is very compact, and lustre shining, in the fracture some- times earthy, sometimes silky; of a bright-green color and streak.

Heated in a matrass, gives out water and turns black. On Ch. fuses to a globule, and affords metallic copper when the heat is sufficiently high ; heated In the forceps,

o.led by

CHARACTERISTICS OF ORES. gg

the outer flame is colored green. With fluxes and Sd. it behaves like oxide of copper (v. Table 11. , S).

It dissolves in acids with effervescence ; also soluble in ammonia,

§ 144. Azurite [Blue Malachite]. — zfCuCCO') + CuO.HO. 55.2CU. H 3.5 — 4- G 3.5 — 3.8. Monoclinic. Occurs usually crjtallized, or in globulat masses of colunmar structure. It is easily distinguished by its fine blue color and streak ; either earthy or vitreous in lustre.

Before the Elp. and with solvents it behaves like mala- chite.

§145. Chaloantlllte [Copper Vitriol]. — CuO.SO' + SHO. H=2.5. G 2.2i. Triclimc. Lustre, vitreous ; color, various shades of blue ; taste, metallic and nauseous.

Heated in a matrass, swells up, gives out water, and becomes white. On Ch., colors the outer flame green, fuses, and affords a button of metallic copper, crusted with a coat of sulphide. After calcination, gives with fluxes the reactions of copper, sometimes also those of iron.

Soluble in water; a polished plate of iron introduced into the solution becomes coated with copper,

§ 146. Paendomalacliite [Phosphate of Copper]. — 3CuO.?0 + 3CCuO.H01,sometimes2(3CaO.PO) + HO 4-4l.CuO HO) 56 6Cu H=4 5 — 5 &=4— 44 OrthorhombiL Occurs both crjstalhzi-d and missive Of adamantine lustre, and daik emerald green or blickish green color Streak, bright green

In a matrass, gives out water and blackens A piece previously heated in a matrass fuses in the foiceps to a black globule, wimh becomes trysfdlme on cooling With Bx and S Ph , behaves hke oxide of oppei. Strongly heated on Ch with a suflicient quantity of &d ,

o.led by

lOO CHARACTERISTICS OF ORES.

nearly ail the copper is obtained as a metallic globule. Mixed with an equal volume of metallic lead and fused on Ch., a globule of metallic copper is obtained, surrounded by a fused mass of phosphate of lead, which on cooling crystallizes.

Soluble in nitric acid and in caustic ammonia.

§ 147. Oliveiiite. — aCuO. (AsOPO=) -f CuO.HO. 45.2CU. H 3. G 4.i — 4.4. Orthorhombic. Crys- tallized, or in globular and reniform masses of indistinctly fibrous structure. Color and streak usually olive-green to brown. Lustre, vitreous.

In a matrass, yields a little water. In the forceps, fuses to a globule and colors the outer flame bluish-green ; the fused mass crystallizes on cooling. On Ch,, fuses with detonation and emission of arsenical vapors to a metallic globule ; the globule is white and somewhat brittle, and covered with a brown scoria. Fused with metallic lead, it is decomposed in the same manner as the preceding ore.

Dissolves in nitric acid, also in ammonia,

§ 148. Tyrolite. — (sCuO.AsO + 9HO) + CaO.CO'. 35, Cu. H=i — 2. 3, Orthorhombic. Usually reniform, massive ; structure, radiate foliaceous. Color, pale-green. Very sectile. Lustre, vitreous.

Heated in a matrass, decrepitates, yields much water, and blackens. On Ch., fuses with emission of arsenical vapors to a gray scoriaceous mass, in which minute glob- ules of metallic copper occasionally appear. When the mineral is fused on Ch., with addition of Sd. and Ex., until the oxide of copper is completely reduced and the slag dissolved in hydrochloric acid, a solution js obtained in which the presence of lime may be shown by the proper reagents. Dissolves in nitric acid with eifervcscence, also in ammonia.

o.led by

CHARACTERISTICS OF ORES. lOl

§149. Chrysocolla.— CuO.SiO'+2HO. 45.8CuO. H 23- G 2, Occurs usually as an incnistation. It very much resembles malachite ; its color is bluish-green, and it is remarkable for its great compactness ; its surface is very smooth, giving it the appearance of an enamel or a well-fused slag. Lustre, vitreous. Streak, when pure, white.

In a matrass, yields water and blackens. In the forceps infusible, coloring the outer flame intensely green. On Ch. in O. Fl. blackens, in R. Fl. turns red. S. Ph. and Ex. dissolve it with the usual indications of copper ; the S. Ph. bead shows a cloud of undissolved silica. With Sd. on Ch., affords globules of metallic copper.

It is decomposed by acids, silica remaining undissolved.

Oees Of Gold, Slatihum, And Ikidium.

§ 150. Native Gold. — Combination of Au, and Ag. in variable proportions, sometimes with traces of Fe. and Cu. H 2-5 — 3. 15.619.5. Isometric. Easily dis- tinguished by its malleability, its cutting like lead, its high specific gravity, and its resistance to acids. Color and streak, various shades of gold-yellow. It usually occurs in variously contorted and branched filaments, in scales, in plates, or in small, irregular masses.

On Ch., fiises to a globule which after cooling has a bright metallic surface. With S. Ph. in O. Fl. a bead is formed which opalizes on cooling, or becomes opaque and yellow, according to the amount of silver which it con- tains.

Resists the action of heated concentrated nitric acid ; soluble only in aqua regia.

§ 151. Sylvanite [Graphic Tellurium].— AgAuTe'. H 1.5 — 2. 7. Monoclinic. Of metallic lustre

o.led by

102 Characteristics Of Ores.

and steel-gray color. Very sectile. Streak and color, pure steel-gray to silver-white ; sometimes yellow.

Ill an open glass tube, yields a white sublimate which, when played upon with the flame, fuses to transparent drops. On Ch. fuses to a dark-gray globule, depositing at the same time a white Ct. which, when touched with the R. Fl., disappears, tinging the flame bluish-green (see §§ 29, 35). It finally affords a light-yellow malleable globule of metallic lustre.

Soluble in aqua regia, leaving a residue of chloride of silver. The solution gives a white precipitate with water.

§158. Native Platinum. — Pt., usually combined with a little Fe., Ir., Os., Pd., Rh., and sometimes Cu. and Pb. 4 — 4.5. G — 16 — -19. Isometric. Usually occurs m grains of silve r- whitish or gray color ; malleable and ductile.

Infusible before the Blp. and not acted upon by fluxes. Soluble only in heated aqua regia. The solution gives a yellow granular precipitate with chloride of potassium.

§ 153. Iridosmine [Osmium Iridium]. — The light variety IrOs' and IrOs H 6— 7. 19.3—21,1. Hex- agonal. Occurs usually in irregular flattened grains, of metallic lustre and tin-white color; but little malleable.

Infusible before the Blp.; when fused with nitre in a matrass the characteristic osmium odor is produced. The fused mass is soluble in water ; the solution gives, on addi- tion of nitric acid, a green precipitate. The dark varieties lose before the Blp. the metallic lustre, and when held in the alcohol flame, impart to it a yellowish-red color and great illuminating power. Not visibly affected by any acid.

Ores Of Iron.

§ 154. Meteoric Iron. — Fe,, with variable quantities of Ni. (from I to 20 per cent.); and traces of Co., Mg., Mn.,

o.led by

Characteristics Of Ores. Io3

Sn., Cu., Cr., Si., C.,C1,,S,, andP. H 4.S. 6 7.3 — 7.8, rarely as low as 6. Isometric. Lustre, metallic; color, iron-gray ; ductile ; strongly attracted by the magnet.

Infusible. On Ch. with Bx. or S. Ph. gives only the reactions of iron. To detect the presence of the other heavy metals, the assay-piece must be dissolved in aqua regia, the liquid mixed with ammonia in excess, filtered, and the ammoniacal filtrates precipitated with sulphydrate of ammonia. The precipitate consists of the sulphides of nickel, cobalt, manganese, and copper, which may be col- lected on a filter and treated with Bx, on Ch. as described §70-

§ 155, Linionite [Brown Hematite]. — 2FeO'.3HO. Sg.gFe. H=5 — -5.5. 6 3.6 — 4. Of a dull brown- ish-yellow color, earthy or semi-metallic in appearance, and often in mammillary or stalactitic forms. Streak, yel- lowish-brown.

In a matrass, yields water, and red sesquioxide remains ; in platinum forceps, fusible on the edges ; gives with Bx. and S. Ph. an iron reaction ; the clayey varieties treated with S. Ph. give a cloud of undissolved silica ; treated with Sd. and nitre on platinum-foil the manganese reaction is almost always obtained.

§ 156. Hematite [Specular Iron]. Fe=0'. 7oFe. H 5.5 — 6.5. 04.5 — 5.3. Rhombohedral. Of a dark steel-gray or iron-black color, and usually of metallic lus- tre ; its powder and streak are red.

Infusible alone ; becomes magnetic after roasting, and gives the usual indications of iron with the fiuxes ; its pow- der dissolves readily in heated hydrochloric acid. Con- tains sometimes chromium and titanium, which may be detected by the processes given §§ 68 and 111.

o.led by

104 Characteristics Of Ores.

§157. Magnetite [Magnetic iron Ore]. —FeO. Fe'O*. 72.4re. 5-56.5. 4.9 — 5-2- Isometric. Its color is iron-black, with a shining metallic or glimmering lustre ; its powder and streak are black ; it is strongly at- tracted by the magnet.

It fuses with difficulty, and gives the usual reactions of iron with the fluxes ; the pulverized mineral dissolves com- pletely in hydrochloric acid.

§ 158, Pyrite [Iron Pyrites]. — FeS=. 46. 7Fe. H 6 — 6.5. G=4.8 — 5. Isometric. Occurs commonly in cubes. Usually of a brass-yellow color and metallic lustre ; sometimes colored or brown by metamorphosis. By its superior hardness, not yielding to the knife, and emitting sparks when struck with steel, it may be distinguished from copper pyrites. Streak, gray.

Heated in a glass tube closed at one end, usually emits some sulphuretted hydrogen, and yields a sublimate of sul- phur ; the residue is attracted by the magnet. Heated on Ch. with the O. Fl. the sulphur bums off with a blue flame and leaves red oxide behind, which, when treated with the fluxes gives pure iron reactions. But slightly affected by hydrochloric acid ; nitric acid dissolves it, leaving a resi- due of sulphur.

§ 159. Marcasite [White Iron Pyrites]. — FeS H 6 — 6.5. G 4,6 — 4.8. Orthorhombic. Crystals are prismatic, often twins. Color usually light bronze-yellow, sometimes inclined to green or gray ; occurs frequently in radiated masses or crest-like aggregations. Streak, green- ish-gray. Very liable to decomposition.

Before the Blp. it behaves like the preceding.

§ 160. Pyrrliotite [Magnetic Pyrites]. — 6FeS + FeS'. 69.5Fe. 3.5— 4-5- 0=4.4—4.7. Hexagonal. Very much resembles common iron pyrites, from which it

o.led by

Characteristics Of Ores. 105

is distinguished by its inferior hardness, more reddish color, and by being sliglitly attracted by the magnet. Strealt, darlt gray.

Heated in a matrass, remains michanged ; in the open glass tube, emits sulphurous acid but yields do sublimate. On Ch. in R. Fl. , fuses to a globule, which is covered with an uneven black coating, which follows the magnet, and which, on a surface of fracture, exhibits a yellowish crys- talline structure and metallic lustre. In O. Fl. it is con- verted into red oxide.

Soluble in hydrochloric acid, excepting the sulphur, with evolution of sulphuretted hydrogen.

§ 161. Arseaopyrite [Mispickel]. — FeS' + FeAs'. 34.4Fe. H=5.5 — 6. G 5 — 6.4. Orthorhombic, Of metallic lustre and a silver-white to steel-gray color. Streak, dark grayish-black. Brittle.

Heated in a matrass, yields first a red sublimate of sul- phide of arsenic, and afterwards a black crystalline one of metallic arsenic ; in an open glass tube, yields arsenous oxide and sulphuroias acid. On Ch., emits copious arseni- cal fumes, and a Ct. of arsenous oxide is deposited ; dien fuses to a globule which shows the properties of fused magnetic pyrites. Frequently contains cobalt, the pres- ence of which may be detected by the method described in § 69.

Soluble in nitric acid and aqua regia, leaving a residue of sulphur and arsenous oxide; the latter dissolves with continued digestion.

§162, Menaeeanlte [Titaniferous Iron]. — Ti''0' and Fe'O' in various proportions. H 5 — 6. 5.5 — S' Rhombohedral. Of iron-black color, usually in tabular crystals ; bears a great resemblance to specular iron, but gives no red powder.

o.led by

106 Characteristics Of Ores.

Alone in the 0. Fl. infusible; in R. Fl. it may be rounded at the edges. With Bx. and S. Ph. in O. Fl., gives the reactions of pure oxide of iron ; but the S. Ph. bead when treated with the R. Fl. assumes a brownish-red color, the intensity of which depends upon the amount of titanic acid present ; this glass, when treated with tin on Ch., turns violet (v. Table II.. § 31). To show conclu- sively the presence of Ti., follow the method given in

§,ii.

Dissolved by hydrochloric acid and aqua regia, with separation of titanic acid ; some varieties dissolve with g a d fti y n when reduced to a very fine powder,

f; 163 Sldente Spathic Iron]. — FeO.CO". 48.23Fe. H~3 5 — 45 3.73.9. Rhombohedral. Color f o g a ye o V to reddish-brown ; crystallizes in hombohed o wh ch are often curved, and are very dis- y ea b often massive. Lustre, vitreous; and s e k b o

H a ed a a rass, frequently decrepitates, carbonic a lad arb n oxide are given out, and a black oxide of iron remains, which is attracted by the magnet. Alone, infusible. With Bx. and S, Ph. it gives the pure iron re- actions, and with Sd. sometimes those of manganese. It dissolves in strong acids with effervescence, but with dif- ficulty, and only when pulverized.

§ 164. Helaaterite [Copperas]. — FeO. S0 + 7HO. 25.9FeO. H=2. 1,83. Monoclinic. Occurs usually massive and pulverulent, of various shades of green, becoming yellowish on exposure to air; taste, astringent and metallic.

In a matrass, gives out sulphurous acid and water, which shows acid reaction. Strongly heated, only sesquioxide of iron remains. Soluble in water.

o.led by

Characteristics Of Ores. 107

1165. Vivianite [Blue Iron Earth]. — 6(3FeO,PO'' + 8H0) + (3Fe'O2P0' + 8H0). H=i.5~a. G=2.66. Monoclinic. Occurs crystallized, or in reniform and glob- ular masses, fibrous and radiated, sometimes as incrusta- tion. Color, blue to green, usually dirty-blue. Vitreous lustre and bluish streak.

In a matrass, swells and gives pure water. In the for- ceps, fuses to a steel-gray metallic globule, coloring the outer flame bluish-green. With fluxes gives the reactions of iron.

Easily soluble in hydrochloric acid and nitric acid. With a solution of caustic potassa, it blackens.

Beramite is of similar character occurring in small foli- ated, columnar masses. 2. Color, hyacinth-red to reddish-brown ; streak, dirty yellow.

§ 166. Scorodite. — Fe'O', AsO' + 4HO. 34-7Fe'0', 49.8AsO. H 3.5 — 4. G 3-1— 3-3. Orthorhom- bic. Crystallized. Color pale ieek-green or liver-brown. Lustre, vitreous ; streak, white.

In a matrass, yields pure water. In the forceps, fuses to a gray scoriaceous slag of metallic lustre, coloring the outer flame paie-blue. On Ch., emits arsenical vapors and fuses to a gray magnetic slag, of metallic lustre, which gives with fluxes the reactions of iron.

Not affected by nitric acid ; forms a brown solution with hydrochloric acid ; partially dissolved by ammonia, leav- ing a brown residue,

Ores Of Lead.

§ 167. Massicot [Plumbic Ochre]. — PbO., containing frequently PbO.CO', CaO, Fe'O', and SiO'. ps.SsPb. G S. Orthorhombic, also isometric. Massive. Lustre,

o.led by

lOS CHARACTERISTICS OF ORES.

dull; color, between sulphur and orpiment-yellow. Streak, light -yellow.

Before the B!p., behaves like oxide of lead.

§168. Minium. — PbO' + aPbO. (i=.6. Pulveru- lent, Color, vivid-red, mixed with yellow.

Before the Blp,, beliaves like oxide of lead.

Withhydrochloricacidevolves chlorine, and is converted into chloride of lead. With nitric acid, becomes brown,

§ 169. Galenite. — PbS. 86.6Pb. H 2.5— 2.75- G 7.25 — 7.7. Isometric. Color and streak, lead-gray; of metallic lustre. Crystals usually affect the cubical form, and possess very perfect cubic cleavage. It is gen- erally argentiferous.

Heated in a matrass, sometimes decrepitates and fre- quently yields a slight white sublimate. Heated in an open glass tube, emits sulphurous acid, and, on the heat being raised, gives a white sublimate of sulphate of lead. Heated on Ch., affords a globule of pure lead, the Ch. becoming at the same time covered with sulphate of lead and oxide of lead. The globule of metallic lead yields gen- erally a little silver on cupellation. The presence of anti- mony is ascertained as shown § 49. Zinc,§i];3. Iron,§83,

It dissolves with some difficulty in boiling hydrochloric acid, with evolution of sulphuretted hydrogen. Very dilute nitric acid has no effect on it, but by a stronger acid it is readily dissolved with evolution of nitrous acid vapors. By fuming nitric acid and aqtm regia it is very violently acted upon, being converted mto sulphate, or a mixture of the sulphate with the chloride.

§ 170. Bournonite. — (sCu'S, Sb'S') + 2(3PbS, Sb'S-). 34.4Pb, 2sSb, 12.9CU. 2.5-3. G 5-7-S-9- Orthorhombic. Occurs crystallized, and massive, granular, compact ; lustre, metalhc ; color and streak, steel-gray.

o.led by

Characteristics Of Ores. Io9

In. a matrass decrepitates, and yields with a strong heat a dark-red sublimate. In an open tube, sulplmrous acid is evolved and abundant antimonial fumes, which con- dense partly on the upper and partly on the lower side of the tube ; the former consists of antimonous oxide, which is volatile ; the latter is not volatile, and consists of a mixture of antimonate of antimony with antimonate of lead. On Ch., fuses readily to a black globule and de- posits a Ct. of antimonous oxide ; with strong heat a Ct. of oxide of lead is obtained ; the remaining globule, when treated with Bx, in 0. Fl., gives the reactions of copper, and the globule assumes the appearance of metallic ropper Dissolves readily in nitric acid to a blue liquid, leaving a residue of antimonous oxide and sulphur Aqua regia leaves a residue of sulphur, chloride of lead, and antimo nite of lead ; the solution gives a precipitate with water Ammonia dissolves a portion of the sulphide of antimony The following ores behave before the Blp. in a very similar manner :

GeocronitB. — sPbS + (Sb, As)'S'. Orthorhombic. Dufrenoyaite. — zPbS + As'S'. Orthorhombic. Boulangerite." gPl'S + Sb''S JameBOiiite. — 2(FePb)S + Sb'S'. Orthorhombic Plagionite. — PbS 4- Sb'S' + iPbS. MonocUnic. Zinkenite, PbS + Sb'S=. Orthorhombic. Meneghenite. — 4PbS + Sb'S'. Orthorhombic. Those minerals in which a part of the SbS' is substituted by As'S', give on Ch. arsenical vapors, and in an open tube a crystalline sublimate.

§ 171. Phosgeaite [Corneous Lead],— PbCl + PbO.CO'. 73.8Pb, H 2. 75 — 3. G 6—6.3, Orthorhomliic, Forms crystals of adamantine lustre, of white, gray, or yellow color.

o.led by

no CHARACTERISTICS OF ORES.

In a matrass, decrepitates slightly and becomes a little darker yellow. On Ch., fuses readily, emits acid vapors, becomes reduced to metallic lead, and gives a white Ct. of chloride of lead and a yellow Ct. of oxide. Dissolves in nitric acid with effervescence. § 172. Cerussite [White Lead Ore]. — PbO. CO'. 77.6Pb. H 3 — 3.5. G=6.4, Orthorhombic. Occurs granuiarly massive, or in prismatic needles, or compressed plates. Color, mostly white, yellow, or gray. Streak, colorless.

When heated in a matrass, decrepitates and turns yel- low ; carbonic acid is given out. Heated on Ch. alone, is reduced to metallic lead. Treated with fluxes, dissolves with effervescence and gives the reactions of pare oxide of lead (v. Table II., 15) ; dissolves readily and with ef- fervescence in dilute nitric acid ; with hydrochloric acid, leaves a residue of chloride of lead ; dissolves in a solu- tion of caustic potassa.

% 173. LeadMUite. — PbO.SO' + 3(PbO.CO=). 75-PlJ- H=2,S. G 6.2 — 6.5. Orthorhombic. Occurs in transparent crystals of pearly or resinous lustre. Color and streak, white, passing into yellow, green, or gray.

On Ch., intumesces slightly, becomes yellow, but white again on cooling ; with greater heat easily reduced to me- tallic lead.

Dissolves it> nitric acid with effervescence, leaving a residue of sulphate of lead.

§ 174. Anglesite [Lead Vitriol].— PbO.SO'. 6S.3Pb. H=2.75 — 3. G 6,2. Orthorhombic. It otten occurs in small octahedral crystals with many facets, but more fre- quently in lamellar masses; of high lustre.

Heated in a matrass, decrepitates and usually yields a little water. Treated on Ch. in 0. Fl., fuses to a clear

o.led by

CHARACTERISTICS OF ORES. Hi

bead, which on cooling turns milk-white; with Sd, on Ch., affords a globule of metallic lead; the Sd. is ab- sorbed by the Ch. and shows, when placed on silver-foil, a strong sulphur reaction. With the fiitxes, gives the re- actions of oxide of lead. Traces of iron or manganese may be detected by Bx. or Sd. as shown §§ 83 and 90,

It dissolves in acids only with great difficulty; by hy- drochloric acid it is partly decomposed ; the pulverized mineral is soluble in a solution of caustic potassa.

§ 175. Pyromorphite [Phosphate of Lead]. — Essentially FbCl + 3(3PbO.PO'). 76.2Pb. H 3.5~4. G 6,5 — 7. Hexagonal. It occurs often in globular masses with a columnar structure, also fibrous and granular. Lus- tre, adamantine. Streak, slightly yellow. Color, green, yellow, and brown.

Heated in a matrass, sometimes decrepitates and yields, with continued heat, a faint white and volatile sublimate of chloride of lead. Heated in the platinum-pointed pin- cers, fuses readily and colors the outer flame blue ; if the amount of phosphoric acid is not too small, the edges of the flame will appear green. With S. Ph. and oxide of copper, gives the reaction for chlorine, § 65. On Ch. in the O. FL, fuses to a globule, which on cooling assumes a polyhedral form and a dark color ; in the R. Fl., yields a Ct. 'of oxide of lead, and the globule, on cooling, assumes dodecahedral facets of pearly lustre. With bora- cic acid and iron wire, gives the reaction for phosphoric acid 95). With Sd. on Ch., affords metallic lead. Some varieties, a portion of the phosphoric acid is replaced by arsenous oxide, which is readily detected by the odor when treated with Sd. on Ch. 54). Also a part of the lead is replaced by lime, as in the brown varieties poly- spherite, miesite, and musierite, while some of the Pb.Cl.

o.led by

112 Characteristics Of Ores.

is replaced by calcium fluoride, thus diminishing the amount of lead.

Soluble in nitric acid, and solution of caustic potassa.

§ 176. Plumho-Gummite. — stsPbO, PO') + 6(A1'0', 3HO). H 4 — 4.5. 6.3 — 6.4. In reniform or globular masses, with a columnar structure ; also, compact massive. Of resinous lustre ; color usually yellowish- brown; resembling gum-arabic in appearance. Streak, colorless.

In a, naatrass, decrepitates and gives out water. In the forceps, intumesces and colors the outer flame azure-blue. On Ch., intumesces, becomes white and opaque, and fuses but imperfectly, depositing a feint white Ct. of chloride of lead. In small quantities, soluble in Bx. and S. Ph. to clear beads. With Sd. on Ch., minute globules of metal- lic lead are obtained. Treated with So. Co. , assumes a fine blue color.

Soluble in nitric acid.

§ 177. Croeoite [Red Lead Ore].— PbO, CrO. 63.2Pb. H=z.5 — 3. 5.9—6.1. MonocHnic. Occurs usually in bright hyacinth-red crystals of adamantine lus- tre. Streak, orange.

In a matrass, decrepitates ; the crystals are broken up into minute pieces and assume a darker color. On Ch., fuses and becomes reduced with detonation ; a Ct. of oxide of lead is formed, and grayish-green sesquioxide of chromium remains with the metaUic globule. With Sd. on Ch., affords a globule of metallic lead. With Sd. on platinum foil, fuses to a dark-yellow mass, which becomes green in R. Fl. With Bx, or S. Ph. in O. Fl., dissolved; the bead appears yellow while hot, but becomes green on cooling. Fused in a platinum spoon with from three to four parts of bisulphate of potassa, gives a dark-violet mass, which is greenish- white when cold.

o.led by

Characteristics Of Ores. Ii3

Dissolves in heated hydrochloric acid to a green liquid, leaving a residue of chloride of lead. Dissolves with dif- ficulty in nitric acid to a yellowish-red liquid. A solution of caustic potassa colors it brown, and finally dissolves it to a yellow liquid.

§178. VaupelMte. — 3CuO,2CrO'-|-3(3PbO,2CrO'). 56.4Pb, S.6Cu. H=2.5— 3. 5.5—5.7. Mono- clinic. Occurs usually in minute crystals, or in reniform or granular masses. Color, dark-green to brown, some- times nearly black. Lustre, adanaantine to resinous ; stroak, greenish to brownish.

On Ch.j fuses with eifervescence to a gray submetallic globule ; where the mass is in contact with the coal, small globules of lead make their appearance ; in R. Fl. a Ct. of oxide of lead is formed. With Bx. or S. Ph. in O. Fl., clear green beads are obtained, which remain green on cooling, but which on application of the R. Fl. become red and opaque ; this reaction appears most distinctly on Ch, with Sn. With Sd. on platinum wire in O. Fl., dis- solves to a transparent green bead, which on cooling be- comes yellow and opaque ; on treating the bead with a few drops of water, a yellow solution is obtained, in which the presence of cliromic acid may be proved as described §68. With Sd. on Ch., is completely decomposed ; on treating the reduced metals with boracic acid on Ch. (v. § 71) a globule of metallic copper is obtained.

Partly soluble in nitric Eicid to a dark-green liquid ; the residue is yellow.

§179. Wulfenite [Yellow Lead Ore]. — PbO, MoO sometimes with a little S7Pb. H==2.75 — 3. G=6.3 — 6.9. Tetragonal. Crystallized or granularly massive, firmly coherent. Color, usually wax-yellow, pasr ing into orange -yellow. Streak, white.

o.led by

114 Characteristics Of Oses.

In a matrass, decrepitates aiid becomes darker while hot. On Ch., fuses and is partly absorbed by the coal, Tvhile metallic lead and a Ct. of oxide of lead are depos- ited. With Bx. or S. Ph. on platinum wire gives the re- actions of molybdic acid (v. Table II., r8). With Sd. on Ch.j affords a globule of metallic lead. Fused with bisul- phate of potassa in a platinum spoon, a yellowish mass is obtained, which becomes white on cooling; treated with distilled water and a piece of metallic zinc placed in the solution, the liquid assumes a blue color.

Dissolves in concentrated hydrochloric acid to a green liquid, leaving a residue of chloride of lead. The pulver- ized mineral is decomposed on being digested with nitric acid ; a yellowish- white residue is left, which becomes blue when exposed to air in thin layers.

OBES OF IffAIfGANESE.

§180, Pyrolusite [Gray Ore of Manganese], —MnO'. 63.3Mn, H=2— 2.5. G 4.8. Orthorhombic. Of black or dark-gray color and Uttle lustre; powder black; sometimes of columnar structure. Streak, black or bluish-black

In a matrass, usually yields a little water ; when heated to redness, oxygen is evohed. Alone infusible, but turn- ing reddish brown when the temperature is sufficientl) high. Soluble in Ex and S. Ph. with the usual mangan- ese reactions ; gives frequently the indications of iron.

Soluble in hydrochloric acid with disengagement of chlorine.

§ 18L Hansmajmite [Black Manganese]. — (MnO)''MnO' 72.iMn. H 5 — 5.5. 4.7. Tetragonal, Crys- tallized, or granular, particles strongly coherent, Color, brownish-black; streak, chestnut -brown.

o.led by

Characteristics Of Ores Ii5

Before the Blp., and with hydrochloric acid, liehaves like the preceding ore.

§ 182. Braimite.~2Mti'0, MnO' + MnO=SiO H 6 — 6.5. G 4.7 — 4.8. Tetragonal. Occurs crystal- lized or massive. Color and streak, dark brownish-black.

In a matrass, does not give any water ; beiiaves other- wise like pjTolusite.' Dissolves in hydrochloric acid witli disengagement of chlorine, leaving sometimes a residue of silica.

§183. Psilomelane. — Composition very various, essen- tially Mn'0= + MnO' wiih BaO, or KO, and HO. H=: 5 — 6. 3.7 — 4-3- Massive, and botryoidal. Color, iron-black; streak, brownish-black, shining.

Before the Blp, and with solvents it behaves like pyro- lusite,

§ 184. Wad [Bog Manganese]. — Essentially MnO', MnO, and HO ; contains often Fe=0', Al'O', BaO, SiO% etc. H o.5 — 6. G 3 — 4.2. Amorphous, earthy, or compact, of a dull black color.

In a matrass, yields water abundantly, and otherwise behaves like pyrolusite. Some varieties, known under the name of " Cupreous Manganese," when treated with Sd. and Bk. on Ch., afford a globule of metallic copper,

§185. Rhodochrosite. — MnO,C0 when pure, some- times (MiiO, FeO, CuO, MgO), CO'. H 3.5—4.5. 3.4—3.6. Rhombohedral. Occurs crystallized, or in globular masses of columnar structure ; also massive. Color, shades of rose-red, brownish ; streak, white.

In a matrass, some varieties give a little water and de- crepitate violently. Infusible. Some varieties, when heated in R. Fl,, become magnetic. Dissolves in fluxes with effervescence, and gives usually the reaction of man- ganese and iron.

o.led by

1 16 Characteristics Of Ores.

The pulverized mineral is little affected by hydrochloric acid in the cold; on heating, dissolves with efferves- cence.

1 186. PraaklMte— (FeO,ZnO,MnO),(Fe'0,Mn'0') usually with a little SiO APO'. H 5.s— 6.5. 5. Isometric. Occurs crystallized, and massive. Lustre, me- tallic; color, iron-black; streak, dark reddish-brown; acts slightly on the magnet.

Infusible. Dissolves in Ex. and S. Ph. with manganese reaction; the Bx. bead, when treated on Ch. in R. Fl., becomes bottle-green. With Sd. on platinum foil, gives manganese reaction. With Sd. on Ch., gives a faint Ct. of oxide of zinc, which becomes m.ore distinct on addition of Bx.

Dissolves completely in heated hydrochloric acid to a greenish-yellow liquid, chlorine being evolved.

ORES or MEECTTET.

§ 187. Native Mercury. — Hg., sometimes containing a

little Ag. r3.5. Metallic globules of a tin-white

Heated in a matrass, is converted into vapor, which condenses in the neck of the matrass to small metallic globules.

Dissolves readily in nitric acid.

§ 188. Amaam. — AgHg 6s.2Hg, and AgHg'. 73-7SHg. H 3— 3.5. 10.5—14. Isometric. Occurs crystallized and massive. Color and streak, silver- white; opaque.

In a matrass, boils, gives a sublimate of metallic mer- cury, and leaves a spongy residue of silver, which on Ch. fuses readily to a globule.

Dissolves readily in nitric acid.

o.led by

Characteristics Of Ores. 1 1/

Arqnerite. — Ag6Hg, is-gHg. Isotnetric. In color, lustre ; ductility like native silver, but softer.

§189. Calomel [Horn Quicksilver]. — Hg'Cl. 84.9Hg. H=i— 2, 6.48. Tetragonal, Occurs usually in distinct crystals, or crystalline coats, of adamantine lustre and yellowish-gray color. Translucent j streak, pale yel- lowish-white.

In a matrass, yields a white sublimate of subchloride of mercury. Mixed widi Sd. and heated in a matrass, affords globules of metallic mercury. On Ch., completely vola- tilized, giving a white Ct. Shows the chlorine reaction when treated as described § 6g.

Treated with boiling hydrochloric acid, is partly dis- solved and becomes gray. Not affected by nitric acid ; dis- solved by aqua regia. With a solution of caustic potassa, becomes black.

1 190. ClDnahar. — HgS. H=2— z.g. 0=8.9. Rhorabohedral. Color, various shades of red, from cochi- neal-red to dark brownish-red. Powder always bright-red. It occurs in very small flattened crystals, or granularly mas- sive. Streak, scarlet, subtransparent to opaque.

Heated in a matrass, is volatilized and condenses to a black sublimate, which by friction assumes a red color. Mixed with Sd., yields on heating globules of metallic mercury. In an open glass tube, is partially decomposed into metallic mercury and sulphurous acid. On Ch. it is, when pure, wholly volatilized.

Nitric acid and hydrochloric acid have no visible effect on it. Aqua regia dissolves it, part of the sulphur being precipitated. Insoluble in caustic potassa.

Ores Of Nickel.

§191. Nieeolite [Copper Nickel], —Ni, As, or Ni>As=.

44.1Ni, 55.9AS. Sometimes part of the As. replaced by

o.led by

1(8 Characteristics Of, Orbs.

Antimony. H 5 — 5.5. G 7-3— 7-6. Hexago- nal. Usually massive ; of copper-red color, with a gray tarnish, and metallic lustre ; very brittle. Streak, dark- brown.

In a matrass, affords a very slight sublimate of arseuoiis oxide. In an open glass tube, yields a copious sublimate of arsenous oxide, and usually a little sulphurous acid ; the assay-piece assumes at the same time a yellowish-green color and crumbles to powder. On Ch., emits arsenical fumes and fuses to a white and brittle globule which, when treated with Bx. in R. Fl. , imparts itsually to the flux the colors of iron and cobalt. Sometimes a faint Ct. of oxide of lead is deposited on the Ch.

Dissolves almost completely in concentrated nitric acid ; the solution has a green color ; on cooling, arsenous oxide separates. Readily dissolved by aqua regia.

§ 192. Oersdorfflte [Nickei Glance], — NiS' + NiAs', or Ni(S,Asy. 35.2Ni.45-SAs. H 5.s. G 5.6— 6.9. Isometric; pyritohedral. Of silver-white or steel-gray color, and metallic lustre. Streak, grayish-black.

In a matrass, decrepitates violently and yields a yellow- ish-brown sublimate of sulphide of arsenic. In an open glass tube, emits arsenous oxide and sulphurous acid. On Ch., fuses with emission of sulphur and arsenical fumes to a globule which, when treated with Bx. in R. Fl., gives the reactions of iron and cobalt. After having removed these two metals, the remaining globule exhibits with the fluxes the reactions of pure oxide of nickel.

Partly dissolved by nitric acid, sulphur and arsenous oxide being precipitated.

§193. Ullmaimite [Nickeliferous Gray Antimony].— NiS + Ni (Sb.As) z7.6Ni. The arsenic is sometimes wanting. H 5 — 5.5. G — 6.2 — 6.5. Isometric. It

o.led by

Characteristics Of Ores. Ii9

closely resembles the preceding ore in its physical proper- ties. Streak, dark-gray.

In a matrass, yields a slight white sublimate. In an open glass tube, emits copious antimonial fumes and sul- phurous acid. On Cb. in R. Fl., fuses to a globule, and coats the Ch. with antimonous oxide ; sometimes the odor of arsenic is observable. The melting globule, when treated with Ex., frequently exhibits the reactions of iron and co- balt besides those of nickel.

It is violently acted upon by concentrated nitric actd, sulphur, antimonous and arsenous oxides being precipi- tated. Aqua regia dissolves it, excepting the sulphur, to a green liquid.

§ 194 Millerite [Capillary Pyrites]. — NiS. 64.9Ni. H 3 — 3.5. 5.2—5.6. Rhombohedral. Occurs usually in delicate capillary crystals of brass-yellow color and metallic lustre. Streak, bright.

In an open glass tube, evolves sulphurous acid. On Ch., fuses with emission of sparks to a metallic globule which is attracted by the magnet. The calcined mineral gives with fluxes the indications of oxide of nickel, and some- times also those of oxide of cobalt.

By heated concentrated nitric acid it is but little af- fected, but its color is changed to gray. By aqua regia it is wholly dissolved.

§195. Zaratite [Emerald Nickel].— (NiO.CO' + 4HO) -I- 2(NiO.HO). 46.5NiO. H 3— 3.2. 0=2.5-2.7. Usually forms incrustations of emerald-green color, and vitreous lustre. Streak, pale-green.

In a matrass, loses already at 212° a considerable amount of water, and blackens. In Ex. and S. Ph., dissolves with effervescence, exhibiting the characteristic nickel reactions.

o.led by

I20 Characteristtcs Of Ores.

Dissolves easily in heated dilute hydrochloric acid with effervescence.

§ 196. Annabete [Nickel Green]. — sNiCAsO" + 8H.0. ap.sNi. Monoclinic. Soft. In capillary crys- tals, also massive and disseminated. Color, fine apple- green. Streak, somewhat lighter.

In a matraK, yields water and darkens in color. In the forceps, fuses and colors the outer flame light-blue. On Ch. in R. Fl., fuses with emission of arsenical vapor to a blackish-gray globule ; when treated with Bx. the globule gives the reactions of nickel, sometimes also those of iron and cobalt.

Soluble in acids.

Ores Of Silver.

§ 197. Native SilveF, — Pure silver, associated with gold, copper, arsenic, iron, and other metals. H 2.5 — 3. — II. Isometric. Color, silver-white; lustre, metallic ; ductile and malleable. Occurs usually in twisted filaments, or arborescent ; sometimes in plates or massive.

On Ch., fuses easily to a globule, which assumes a bright surface, and shows after cooling a silver-white color. For- eign metals are detected by the methods given §§ 103-

It dissolves in nitric acid.

§ 198. DySCrasite [Antimonial Silver]. —Ag'Sb. and Ag'Sb. H 3.5 — 4. 9.4 — 9.8. Orthorhombic. Occm crystallized or massive ; granular. Lustre, metal- lic ; color and streak, silver-white.

On Ch., fuses readily to a gray non-ductile globule and coats the Ch. with oxide of antimony ; with continued heat the globule assumes the appearance of pure silver, and the Ct. becomes reddish.

o.led by

Characteristics Of Ores. 121

Dissolves in nitric acid, leaving a residue of oxide of aniimonj'.

§199. Cerargyrite [Horn Silver].— AgCl. 75-2Ag. H=i — 1,5. 0=5.5. Isometric. Remarkable for its pearl-gray or greenish color, its semi -transparency, resin- ous lustre, and more especially for its softness, which is so great as to allow it to be marked by the nail. It turns brown on exposure to air. When rubbed with a moist- ened plate of zinc or iron the latter becomes covered with a coating of silver. The streak is shining.

It fuses in a candle-flame. On Ch., is easily reduced, especially when mixed with Sd. tixed with oxide of copper and heated on Ch. in R. Fl., chloride of copper is formed, which colors the flame azure-blue (v. § 65).

Insoluble in water and nitric acid. Slowly soluble in caustic ammonia. Partially decomposed by a boiling solution of caustic potassa.

§ 200. Embolite [Chloro-Bromide of Silver]. — AgBr. and AgCl. in varying proportions. 61 to eg.SAg. H I-— 1.5. 0=5.3 — 5-4- Isometric, Crystallized or mas- sive. Lustre, resinous ; color, various shades of green.

On Ch., fuses readily, evolves pungent vapois of bro- mine, and affords a globule of metallic silver. With Sd. on Ch., reduced ; on dissolving in water the alkaline mass which has passed into the coal, evaporating the solution to dryness, and treating the residue with bisulphate of potassa as described § 63, bromine vapors are given out. Fused with oxide of copper on Ch. in R. Fl., colors the outer flame greenish, then blue (v. § 65).

§ 20L Bromyrite [Bromic Silver]. — AgBr. 57.4Ag. H 2 — 3. 5.8—6. Isometric. Occurs usually in small concretions. Lustre, splendent ; color, yellowish- ' green or green. Sectile,

o.led by

122 Characteristics Of Orbs.

Before the Blp. on coal emits bromine vapors and yield a globule of silver. Fused with bisulphate of potash, in a matrass, gives off yellowish-brown vapors of bromine. Insoluble in nitric acid ; sufficiently soluble in ammonia.

§ 202. lodyrite [Iodic Silver].— Agl. 46Ag. Soft. G 5.5. Hexagonal. Occurs crystallized or in thin plates with a lamellar structure. Color, citron-yellow to yellowish-green. Lustre, resinous to adamantine.

On Ch., fuses readily, colors the flame purple-red, and affords a globule of silver.

§ 203. Argentite [Silver Glance]. — AgS. 87.iAg. H 2 — Z.5. G j. Isometric. Color, blackish lead- gray ; lustre, metallic. It is easily distinguished from other minerals of the same color by being cut by a knife like lead.

On Ch. in 0. FL, intumesces, gives out sulphurous acid, and finally yields a globule of metallic silver.

Soluble in dilute nitric acid, leaving a residue of sulphur.

JaJpaite. — A cupriferous silver glance from Mexico. Color, blackish lead-gray.

AcaBthite. — AgS. Orthorhombic. Reactions the same as for Argentite.

§ 204. Pyraxgyrite [Dark-red Silver Ore].— sAgS, SbS 59-9Ag. 2 — 2.5. G 5-7—5.9. Rhom- bohedral. Color, dark-red to black, giving a cochineal- red powder. Crystallizes in hexagonal prisms. Streak, cochineal -red. Lustre, metallic -adamantine.

In a matrass, fuses very readily and jnelds with contin- ued heat a sublimate of tersulphide of antimony. In an operi glass tube, gives antimonia! fumes and sulphurous acid. On Ch., fuses readily and deposits a Ct. of anti- s oxide, being converted into sulphide of silver ; if a long time exposed to the O. Fi. , or, when mixed with , in the R. Fl., affords a globule of metallic silver.

o.led by

Characteristics Of Ores. 123

P 1 SbS one me 1 lb -YsS'; it

h n g ou 1 fumes h n d 1 Sd. and

h a a n h R Fl CI

Thil laedwl c acid,

t n bla k and 1 ly d ol d 1 a ng a residue

o ulph and an mo ous ad Ca is po a sa also black n and ff pa al olu on fon svh h acids pep Ipl d of n y

§ 205. PrOUStlte [Light-red bilvcr Ore]. — 3Agb, As'9S. 6s,4A.g. H 2~2.s. 0=5.4—5.5. Rhombohe- dral. Very much resembles the dark-red silver ore, but is of a somewhat lighter color. Lustre, adamantine.

Before the Blp. and to solvents, behaves like the preced- ing, excepting it gives off arsenical fumes instead of anti- nionous oKide. The solution in caustic potassa deposits a yellow precipitate when neutralized with acids.

§ 206. Stephaaite [Brittle Silver Ore]. — 5AgS, Sb'S'. 68.5Ag. 2—2.5. G 6.2. Orthorhombic. Of metallic lustre and iron-black color and streak ; it is very brittle and fragile.

In a matrass, decrepitates, then fuses and ultimately yields a faint sublimate of tersulphide of antimony. OnCh., fuses very readily and coats the Ch. with antimonous acid. If the blast with the O. Fl. is kept up for a sufficient time, the Ct. assumes a red color and a globule of metallic silver is obtained. Contains frequently copper and iron, which may be detected by the process described § 71. If arsenic is present it gives in the open tube a crystalline sublimate of arsenous acid.

In dilute heated nitric acid tt dissolves, excepting the sulphur and antimonous oxide ; the solution becomes milky on addition of water. Partially dissolved by a boiling solution of caustic potassa.

o.led by

124 Characteristics Of Ores.

§ 207. Polybasite. — 9 (-g, Cu'jS + (Sb, As)=S'. H 2—3. G=6.2. Orthorhombic. Occurs usually in short tabular prisms, or massive. Lustre, metallic ; coloi and streak, iron-black.

In a matrass, fuses very readily, but gives nothing vola- tile. In an open tube, gives sulphurous acid and antimo- nial fumes ; the sublimate contains sometimes crystals of arsenous acid. On Ch., gives a Ct. of oxide of antimony ; with continued heat, gives a bright tnetallic globule, which, on cooling, becomes black on its surface ; sometimes a faint Ct. of oxide of zinc is deposited j the metallic globule af- fords with fluxes the reaction of silver and copper.

With acids behaves like bournonite.

§ 208. Stromeyerite [Argentiferous Sulphide of Cop- per].— Cu'S. + AgS. S3Ag, 31.2CU. H 2.5—3. 6.2—6.3. Orthorhombic. Occurs usually in small, compact masses. Lustre, metallic ; color, dark steel-gray. Streak, shining.

In a matrass, fuses easily and gives sometimes a little sulphur. In an open tube, fuses to a globule and gives sulphurous acid. On Ch., fuses to a gray metallic globule which is a little malleable ; with fluxes the globule gives the reactions of copper, sometimes also those of iron ; on a cupel with lead affords a globule of silver.

Dissolves in nitric acid, leaving a residue of sulphur.

Ores Of Tin.

§209. Caasiterite[TinOre]. — SnO=. 78.67Sn. H 6 — 7. 6.3 — 7.1. Tetragonal. It occurs crystal- lized in square prisms terminated by more or less com- plicated pyramids ; re-entrant angles are so frequent that they are to a certain extent characteristic; also massive, and in small mammillated masses of fibrous texture, hence

o.led by

Characteristics Of Ores. 125

called "wood tin." Color, very various, but usually brown or black. The crystals commonly possess a very brilliant lustre.

Infusible in the forceps; the behavior before the Blp. is that of pure oxide of tin (v. Table II., 30), excepting that it sometimes imparts to the Bx. bead a slight yellow- ish tinge, owing to the presence of iron, and exhibits the reaction for manganese when fused with soda and nitre on platinum-foil.

Insoluble in acids. Fused with caustic potassa, yields a mass which is mostly soluble in water,

§210. Stannite [Tin Pyrites]. — 3 (Cu', Fe, Zn)S + SnS so.gSn. H 4. G==4-3— 4.S- Probably tetrag- onal and hcmihcdral. Of steel-gray or iron-black color, and metallic lustre. Occurs usually massive, granular, and disseminated. Streak, blackish:

In an open glass tube, yields sulphurous acid and oxide of tin, which collects close to the assay-piece, and which cannot be volatilized by heat. On Ch. in R. Fl., fuses to a black scoriaceous globule ; in O. Fl., gives out sulphurous acid and becomes covered with oxide of tin. When well calcined by the alternate application of O. Fl. and R. Fi., gives with Bx. the indications of Fe. and Cu. With Sd. and Ex., yields a globule of impure copper.

Decomposed by nitric acid, a blue solution js obtained, and a mixture of sulphur and oxide of tin remains Undis- solved,

Ores Of Zinc.

§ 211. Ztnoite [Red Zinc Ore]. — ZnO, containing .some

MnW, or MnO'. 8o.z6Zn. H 4—4.5. G 5.4—

5.5. Hexagonal. Of a deep-red color and high lustre;

of distinctly foliated structure, and orange-yellow streak.

o.led by

126 Characteristics Of Ores.

Infusible alone. Dissolved by Bx. in 0. Fl. with man- ganese reaction. Witli Sd. on Ch., deposits a copious Ct. of oxide of zinc.

Soluble in nitric acid without effervescence j in hydro- chloric acid with evolution of chlorine.

§ 212. Splialerite [Blende]. —ZnS. 67. Zn. H 3.5 — 4. 0=3.9 — 4.2. Isometric. Of very variable color, from yellow to black; of resinous lustre and lamellar aspect, distinctly cleavable. It occurs often crystallized in rhom- boidal dodecahedrons. The powder is always light-col- ored, white or grayish, and dull.

In a matrass, sometimes decrepitates violently, tut gives nothing volatile ; its color also remains unchanged, except- ing the green varieties, which become yellow. Strongly heated in an open glass tube, sulphurous acid is evolved, and the color of the calcined assay is white, yellowish, or brownish, according to the amount of FeS. which it con- tains. Alone, infusible or only rounded at the thinnest edges. On Ch. in R. Fl, a feeble dark Ct. of oxide of cadmium is usually obtained, which is soon followed by a pure zinc-Ct. With Sd. on Ch., is easily reduced, and the characteristic zinc-flame may frequently be observed. Iron is readily detected by calcining the mineral in the 0. Fl. and treating the residue with Bx.

The pulverized mineral dissolves in nitric acid, leaving a residtie of sulphur.

§ 213. Smithsonite [Carbonate of Zinc].— ZnO.CO'. 52Zn. H=g. G 4 — 4.5. Rhombohedral. Of vitreous lustre, and white, grayish, or brownish color and streak ; semi-transparent or opaque. Often stalactitic or mam- Heated in a matrass, loses carbonic acid, and, if pure, appears after cooling enamel-white. The ZnO. is often to

o.led by

Characteristics Of Ores. 12/

a large extent substituted by FeO., MnO., CdO., PbO., MgO., CaO. ; it tlien, after cooling, frequently assumes a. dark color and gives with fluxes the indications of iron and manganese. Mixed with Sd. and exposed to the R. Fl., it is decomposed, and oxide of zinc deposited on the Ch. If the temperature was raised sufficiently high, a zinc-flame is sometimes observable. The Ct. is at first dark- ye How, or reddish, when cadmium is present.

It readily dissolves in acids with effervescence ; also in caustic potassa.

§ 214. Calamine [Hydrous Silicate of Zinc]. — aZnO, SiO' + HO. 67.5ZnO.,withsometimesallttlelead. H 45 — 5- G 3-1 — 3.9. Ortliorhombic. It closely resembles in its physical characters the preceding ore. It is electric by heat ; the smallest fragment heated attracts light substances.

Infusible in the forceps. In a matrass yields water and turns milk-white. Bx, dissolves it to a transparent glass, which cannot be made opaque by flaming. It dissolves in S. Ph. to a transparent glass which becomes opaque on cooling, and in which, when highly saturated, clouds of silica are observable while hot. With Sd. on Ch., swells and affords with difficulty a Ct. of oxide of zinc. With SoCo., assumes a green color, which, when the heat is raised, passes into a fine light-blue on the fused edges.

It is readily decomposed by acids, with separation of gelatinous silicic acid. Partly dissolved by caustic po- tassa.

§ 215. Willemite [Anhydrous Silicateof Zinc].— aZnO, SiO and often containing a little MnW, Fe'OS CaO, and MgO. ya.gZn. H s.5. 3.89— 4.18. Rhom- bohedral. Lustre, vitreo- resinous ; weak. Color, whitish

o.led by

128 Characteristics Of Ores.

or greenish- yellow, when purest ; green to dark-brown when impure. Streak, un colored. Transparent to opaque. Brittle.

Before the Blp., in the forceps glows and fuses with dif- ficulty to a white enamel ; the varieties from New Jersey fuse from 3.5 to 4. The powdered mineral, on coal in the R. Fl., gives a coating, yellow while hot, and white on cooling, which, moistened with So. Co., and treated in 0. Fl., is colored bright-green. With soda the coating is more easily obtained.

Decomposed by hydrochloric acid with separation of gelatinous silica.

Fossil Fuel, And Carbonaceous Compouitds.

§ 216. Graphite [Plumbago]. — C. Hexagonal. In flat six-sided tables. H i — z. 2.089. Lustre, me- tallic. Streak, black and shining. Color, iron-black to dark steel-gray. Opaque. Sectile ; marks paper. Thin ; laminje flexible. Feel, greasy.

It occurs also foliated, columnar, radiated, scaly, gran- ular and massive.

At a high temperature it burns without flame or smoke, leaving usually some red oxide of iron. Before the blow- pipe infusible ; fused with nitre in a platinum spoon defla- grates, converting the reagent into carbonate of potash, which eff"ervesces with acids. Unafi'ected by acids.

§ 217, Antliraeite. — C, from So to 95 per cent., with a small percentage of SiO', A?0', and Fe'C H 2— 2.g. G 1.3 — 1.8. Lustre, bright, often sub-metallic ; color, iron-biack, frequently iridescent. Fracture, con- choidal.

In a matrass, gives usually a little water, but no empy- Heated on platinum foil in 0. Fl., is slowly

o.led by

Characteristics Of Ores. 1 29

consumed without flame, leaving a small quantity of ash, which consists of SiO=, Al'O', and more or less Fe"0'. Does not color a boiling solution of caustic potassa.

§ 218. Bituminons CoaL — C, H,, O., in variable pro- portions ; the bituminous matter contains from 76 to 90 per cent, of carbon ; the earthy impurities consist princi- pally of SiO% Al'O', and CaO ; contains frequently a small amount of N, and FeS'. Softer than anthracite, G 1.2 — 1.5. Less highly lustrous than the preceding, and of a more purely black or brownish-black color.

In a matrass, some varieties soften and cake {caking coat), while others are entirely infusible ; all varieties are decomposed, evolve combustible gases and empyreumatic oils, and leave a residue of more or less metallic lustre (coke), which behaves like anthracite. On platinum foil, burns with a luminous flame and emission of smoke, leav- ing an earthy residue.

Boiled with a solution of caustic potassa, or with ether, imparts to these solvents no, or only a pale-yellow, color,

§ 219. Browu Coal, — Composition the same as that of bituminous coal, but the organic constituents contain only from 60 to 75 per cent, of carbon. In physical proportion bears sometimes a close resemblance to the preceding; some varieties show distinctly the texture of wood Qigmte):

a matrass, infusible, but some varieties soften ; evolves combustible gases, empyreumatic oils, water of acid reac- tion, and a peculiar disagreeable odor, leaving a residue which consists of carbon and a considerable amount of ash. On platinum foil, burns with a smoky flame and emission of a peculiar odor.

Boiled with a solution of caustic potassa, colors the liquid brown.

o.led by

130 Characteristics Of Ores.

% 220. Aspialtum. — C, H,, 0., in variable propor- tions, with about 75 per cent, of carbon. i — 1.2. Of black or brownish-black color, and bituminous odor.

Fuses at about 100° C, and burns with a bright flame and emission of a thick smoke, leaving little ash, which consists essentially of SiO', Ai'O', and Fe'O'. In a mat- rass, gives empyreumatic oil, some ammoniacal water, com- Jjustible gases, and leaves a carbonaceous residue.

Treated with boiling ether, colors the solvent wine-red to brownish-red (distinction from bituminous coal) ; treated with a boiling solution of caustic potassa, does not color the liquid, or imparts at the most a pale-yellow color (distinction from brown-coal).

§ 221. Succinite [Amber]. — C'H'O (SchrStter). 2 — 2.5. 1.065— 1.081, It occurs in irregular masses, without cleavage. Lustre, resinous. Color, yel- low; sometimes reddish, brownish, and whitish; often clouded. Streak, white. Transparent, translucent. Taste- less. Electric on friction. Fusesat 287° C, but without becoming a flowing liquid.

It consists of succinic acid, resins, an ethereal oil, and puccinite proper, an insoluble substance.

Amber fuses with some difficulty in the matrass, yielding water, empyreumtie oil, gases, succinic acid, and a resi- due of amber-resin. It burns with a yellow flame, emit- ting an agreeable odor, and leaving a black carbonaceous mass.

§ 222. Elaterite [Elastiq Bitumen]. — CH' (mostly). 0=0.905 — 1-233. Soft, clastic, like India-rubber, but sometimes liard and brittle. Color, dark-brown. Sub- translucent.

Burns in the flame of a candle, and gives empyreumatic products when fused ii

o.led by

Chapter V.

Systematic Method for the Determination of Inorganic Compounds.

The careful observer, having become well acquainted with the reactions which are exhibited by the metallic oxides and other simple compounds, when subjected to the vari- ous treatments detailed in the. second chapter, will find no difficult)' in ascertaining the nature of any mineral sub- Stance presented to him for analysis.

If the reactions are not quite distinct, owing to an in- termixture with other substances he may call to his aid

the processes la d 1 enable him, n impurities. B this way, a is a necessar directions a 1

Those, ho blow-pipe op ficulties in d served phen m obviated by p

h d

thodical c the answer thus leading 1 path, to th J

1 p r, which w

1 nature of the

f ory results in

h principal tests

J d, any further

1 much time to

pe nee some dif-

from the ob-

great extent

h ! '. This me-

g the operator

h observes, and

jy 'ery tortuous

pi 'ill sliow this

'3>

o.led by

133 Determination Of Compounds.

more clearly, and teach at the same time the use of the table.

Suppose a substance be given for analysis. The opera- tor commences with No, i. The substance is heated va. R. Fl. on Ch: a garlic odor is disengaged; proceed to No. 2. Treated with Sd. on Ch. does not give a mass which exhibits the reaction of sulphur; proceed to No. 3. The substance shows no metallic aspect ; proceed to No. 131, thence to No. 135. It is not wholly volatilized, nor does it exhibit the reaction of sulphur ; proceed to No. 137. Here we find that the substance must either be an arsenite or an arsenate (which of the two cannot be de- cided by the Blp. alone), and to find the metal, we pro- ceed to No. 102. It affords, afier calcination, with Sd. on Ch., a fusible metallic button; proceed to No. 103. The button is oxidizable (because on being heated in O. Fl., becomes covered with a black coating of oxide) ; proceed to No. 105. The button is red and malleable ; the metal is copper. The substance, therefore, was arsenite, or arsenate, of copper.

The chief constituents of the body having thus been as- certained, the analyst should never omit to test the cor- rectness of the result by the processes laid down in the third chapter. In the example given above, he should verify the result by the test given in g 5 7 for arsenous acid, and by those given in §§ 71 and 74 for copper. If we wish to examine the assay also for the presence or absence of some accessory constituents, we must always have re- course to the methods detailed in Chapter III. For exam- ple, having found the body under trial to consist essen- tially of sulphur and lead, and it appears desirable to know whether or not it contains any silver, we must sub- ject it to the treatment described § 103.

o.led by

DETERMINATION OF COMPOUNDS. fOn Ch. (R. FI.), with or without Sd., disengages a garlic

/ Metallic aspect. Arsmide. 131

Not(unless slrongly heated).

( Treated as indicated 65, imparts to the flame an azure-blue

or green color

Not Nitrate. 1

! Treated as indicated 63, disengages deep-yellow vapoi-s. Sromats. I Not Chlorate. 1

("Treated as indicated 63, disengages deep-yellow vapors, [violet vapors Icdate. I

Heated in a matrass with bisulphite of potassa and a little

binoxide of manganese, disengages violet vapors

Iodide and Jodaie. v

Deep-yellow vapors Brotrndt and Bromate. 1

Not

{Treated as indicated 77, exhibits the t?uorine-reaction Fluoridt. I Not

Ho.led by

;4 Determination- Of Compounds.

Treated as indicated 65, imparts to Ihe Hame an azure-bine

A green color l6

Heated with Sd. on Ch., gives a mass wiiich, when mixed

with bisulphate of potassa and black oxide of manganese, and heated in a cloaed tube, evolves a deep-yellow gas.

Bromide. loz

Not Chhride and Chlorate. 102

" Heated with Sd. on Ch., gives a mass which, when mixed with bisulphate of potassa and peroxide of manganese, and

heated in a closed tube, evolves violet vapors Iodide, loz

Deep-yellow v9.pors Bromide. 102

r EfFervesees with hydrochloric add Carbonate. I02

I Not „. 18

is]

In

{Fused with Sd. on Ch., yields neither a metallic globule n aCt Yields a mefaliic globole or a Ct

( Treat*

(The scoriaceous mass is heated in a platinum spoon or on platinum foil, with a drop of concentrated sulphuric acid, then alcohol poured 00 it, and lighted. The flame appears yellowish- green Berate. i02

f Heated with Sd. on Ch. yields a metallic button 25

o.led by

Determwa Tion Of Compounds.

j With Sd. on Ch., yields a metailic burton or a copious Ct... 31

Pulverized and fused with five or six limes its weight of Sd. in a platinum spoon, or on piitinunt foil, yields a mass which, when heated with hydrochloric acid, gives a gela- tinous precipitate 30

f Metallic aspect 31

1. White button,

{With Bx. on platinum wire, gives a bluish gli Not

Gelii with Cepper.

Gold.

f With Bx. on platinum wire, gives a bluish glass

' Silver with Capper. Silver.

1 platin:

("Witl

I Not

f Gives with Bx. the reactions of oxide of copper

3'tNot

of Red and malleable metallic button Copper.

j Malleable, yellow or reddish alloy Copper and Zinc.

1. White, malleable alloy Capper, Zinc, NitkeL

43 .j Very fusible metallic button

r Deposits on Ch. a a

No Ct. deposited onCh.; exhibits the reactions of tin... Tan.

Ho.led by

Determination Of Compounds.

{Yields on Ch. a brittle globule, which exhibits the antimony reiclions. See 30 AnHmony. Not Tellurium.

{Metallic aspect, or powder assuming metallic lustre under the polishing steel 47 Not 50

f Infus

„ ( With Bx, in O. Fl,, an amethyst- colored ss,%...Manganise.

I" After having been oxidized, eihilMts with fluxes the iron- J reactions Iron.

I After having been oxidized, exhibits with fluxes the nicltel- I reactions Nickel.

So{

Yields with Sd.onCh.in R. Fl.a tin globule..OOTfltD/r/.

{Yields with Sd. on plutinum foil in O. FI., a bluish-green mass 53 Not 54

I- Gives with Bx. or S. Ph. on platinum wire, an amethyst-

53 J colored bead Oxide of Manganese.

(Not. Brown powder Tungstale of Irsn and Manganese.

iWith S. Ph. on platinum wire in K. Fl., gives a glass which, on cooling, becomes brownish-red and, when touched with tin, violet-red Titaniferom Iron. Not; exhibits the iron-reactions 55

I" Heated in a closed glass tube, yields water ; powder, yellow

55 J Hydrate of Sesqmoxide of Iron.

I. Yields no water 56

S'*\Oxidiiable button...

Ho.led by

De Termina Tion Of Compounds.

/Button with Ct 6i

Malleable button withoot Ct 75

!The suhstanoo U yellow or reddiat. Protexide of Ltad. The substance is red Minium. The substance is brown Binoxide of Lead.

( Affords with Ex., or S. Ph. in O. Fl.. a green bead-

65-! , Chromate of Bismuth.

(Not Oxide of Bismuth.

I- Treated on Ch. in O. Fl. deposits a Ct., or vaporizes com-

r The substance is red or yellow, and affords, when heated in

a closed glass tube, metallic asxi:.\ix. .. Oxide ef Ma-ctay,

The substance is white, becomes yellow on heating, and on

cooling, white again OxideofZiac.

{Affords with Bs. a bead which is

Not

fTheBx. bead is green in both flames 72 Not 77

Soluble in water 73

72

o.led by

i8 DETERMINATION OF COMPOUNDS.

{The ubslaiice is of sub metallic aspect or gri) ish bUck Lkromic Iran The substani-e is i green powder Sesquwxtdf of Chromium Oxide of Tin

i Tlie substance IS red or brown Suboxide of Co/>p(r

The substance is black Proloxide of Copper

S The head is gi een m O Fl and becomes reddish brow n in

Gives off water w hen heated in a gKss tube

J Hydrated OAide of 3Ia?iganise.

Osidi of Manganese.

f Heated alone on Ch. in O. Fl. becomes magnetic 55

JNot 81

Exhibits with S. Ph., on platinum wire, the uranium reac- J tions Oxide of Uranium.

r, exhibiting alkaline rt

g f Hea.ted on platinum wire, fuses readily and vaporizes

o. ( Heated on platinum foil, stains it dark-yellow Lithia.

f Heated on platinum wire, colors the flame pale-violet

jjfi J Mydrak of Fotaisa.

1 Reddish-yellow ; the outer flame becomes enlarged

Hydrate of Soda.

( Moistened with a drop of hydrochloric acid, and heated on

87 platinum wire, colors the flame pale-green Baryta.

(.Crimson Strontia.

r Heated with SoCo.,

Ho.led by

De Termina Twn Of Compo Unds. 1 39

t Heated with SoCo., assumes a line Hue color 4lumt}ta " \Not 9Z

r Heated with SoCo., assumes a flesh color Magaeii !

nNot 93

„, r Heated with SoCo., assumes a green color On<fe of Zinc 531 Not 94

C Affords with S. Ph. in 0. Fl. a colorless glass, which in R 94 -j Fl. becomes blue 9S

(.Not 97

{Heated in a closed glass tu!i, evolves ammania and becomes blue or green 7\ingstati of Ammonia. Not 96

, f On Ch. alone, infusible TungiHc Acid.

5°\ Fusible Tms'lal'of Peiassa o>- Soda.

f Exhibits with S. Ph. the reactions of. Molyhdie Acid.

97|Not 93

„ f Exhibits with S. Ph. the reactions of pure Titanic Acid.

9tNot 99

(With Sd. on Ch. in R. Fl., affords a metanic powder at- tracted by (he magnet Oxide of Nickel. Not : affords with S. Ph. in O. Fl. a glass which, while hot, is red, and colorless when coid Oxide of Cerium.

Nitrates, Chlorates, Bromates, Iodates, Carbonates, Phosphates, Borates, Chlorides, Bromides, Iodides, Oxides, Hydrates.

/Affords with Sd. onCh.in R. Fl., a fusible metallic button. 10.;

t Not 109

Ho.led by

Determination Of Compounds.

„ /The button is malleable Salt of Lead.

'"tThebulton is brittle SaU of Bismuth.

f Treated with Sd. on Ch. in R. Fl., deposits a Ct ]

51, Not

{Tiie Ct. is reddish-brown Salt of C Tlie Ct, is yellow while hot, and white when cold Salt of Zinc.

rOn Ch. alone, affords a gray and infusible powder which,

j under the polishing steel, assumes metallic lustre

Salt of Flatmum.

{Heated with Sd. in a closed e'sss tube, disengages ammo- nia Salt of Ammonia. Not 1

{Gives with Bx. or S. Hi, beads which are blue in both flames Salt of Cobalt. Not I

, f The beads are green in both flames Salt of Ckromiam.

("The bead exhibits the reactions produced by oxide of cop- 117 J per Salt of Copper.

Ho.led by

Determination Of Compounds.

i Infusible mass, which assumes, with SoCo , heated in O.Fl., a fine blue color. Salt of 4lumtna A flesh color Salt (Magnesia Not

f The watery solution gives a precipitate on addiiion of some

Sd

[Not

fHeated on platinum wire, colors the flame pale-green

,,J Salt Bf Barytn.

j Colors the flame crimson Salt ef SIrontia.

[Not; but becomes very luminous Salt ef Lime.

("Heated on platinum wire, colors tlie flame violet

124 J Salt ef Potaisa.

Colors the flame reddish-yellow Sail of Seda.

Sulphur Compounds.

, , f Metallic aspect; sulphides 126

, f Tlie substance is calcined, and the metal detected by pro- 1 ceeding as indicated above, beginning with No 102

{Sulphates, hyposulphates, sulphites, hyposulphites, sul- phides prepared artifidally by precipitation, and a few native sulphides 128

fHeated wilh hydrochloric acid, disengages:

ilphuretted hydrogen Sulpkids. 130

Sulphurous acid 129

"' " Sulphate or Hypesulpkste. I30

LNol

("Hydrochloric acid produc

[Not

130.] The metal is detected, beginning with No...

Arsenic Compounds.

o.led by

Determination Of Compounds.

dily and

mpletely volaUlised on Ch

es a white

nd very volatile Ct

("The substance, which is an arsenide or siilpharsenide, is

134 J thoroughly calcined, and then the metal detected as in-

dicated above, beginning with No 11

[ Wholly volatilized on Ch., and exhibiting the reactions of

135 J sulphur

[ Not wholly volatilized, or exhibiliog no sulphur-reaction, 1,

,/ The substance is yellow Oriameni.

'3°\The substance is red -Sear.

! The substance is very volatile Anenom Oxide. Not : arsenite or arsenate. The substance is well calcined with alternating O. Fl. and R. Fl., and the metal found, beginaing with No r

Selenium Compounds.

r Metallic aspect SeUnide.

138] Not: selenile or selenale ; the substance is well calcined, L and the metal delected, beginning with No !

fWith Sd on platinum wire m Fl affords a

J blue mass

[Not

Heatei with Sd m a closed glass tube, evolves

£iILIL1.TE-,

The analogy in chemical composition and properties, and the number of native silicates, make it impossible to dis- criminate them by a few simple tests,* The base or bases may, however, in many cases be detected by pro- ceeding as indicated above, beginning with No ,.

.,t.db,

Determination Of Compounds. I43

The following Eclieme for tte determination of inorganic sub- stances, by Prof. T. Egleston, of Columbia College School of Mines, appeared in the American Chemist for February, 1872. In the orig- inal, the numbers referred to Prof. H. B, Cornwall's excellent trans- lation of Plattner's Manual.

The substance may ci Cu — Co—m—Pb Sn—Ct—JBr—X-

-JPe—Mti-

If there are volatile su inces present, form a coating ar .t it with S. Ph. and lin on C

i. If there are no vola stances present, divide a tlie sutsiance into three and proceed as in i.

and Bi.

i Vellow coa

bead with S. Ph.,

disappearing with green flai c Yellow coat, very similar ti

and Sb. S. IfAs — Sb — S — Sem oughly on Ch. until no odot of i Divide the gubstanoe

i, but yielding no blue flame ; St

a laje quantity thor-

rous acid is given off.

A. Treatment of the First Portion.— Dissolve a very small quantity in borax on platinum wire in the O. F. and observe the color produced. Various colors will be formed hj the combination of Ihe oxides. Saturate the bead and shake it off into the porcelain dish, repeat this once or twice. 37 and Table III.

i. Fe — Mn — COf etc., re- main in the bead. J 71.

If the bead spreads out on the Ch., it must be collected to a globule by continued blowing.

Make a borax bead on platinum wire and dissolve in it let/ie of the fragments pf the bead, reserving the rest for accidents.

Sn — Pb—Bi are reduced and collected by the lead button. J 71. (Sn,Pb,Bi, if present, partly volatilize.)

Remove the lead button from the head while hot, or by break- ing the latter, when cold, on the anvil between paper, carefully preserving all the fragments.

.,t.db,

Setmrmination Of Compounds.

d. If Co is present, the bead . will be blue. I

If a large amount of Fe is : present, add a liltle borax to prove the presence or absence of Co.

If Mu is present, the bead, when treated on platinum wire in the O. F., will become dark violet or black.

/. Treat the button f on Ch. in the O. F. until all the lead, etc., is driven oft'; 2ii, Cn, A.g, Am remaining behind; or separate the lead with boracic acid. J 71.

is hot.

n O. F. with S. Ph. bead, r

h. If Ni and Cu are present, the bead will be green when cold. §72. IfJVi only — yellow. If Ga only — blue.

Prove Cu by treating with tin onCh. intheR. F. 371.

B. Treatmemt of the Second Portion. — Drive oft' the volatile substances in the O. F. on Ch. Treat with the R. F., or mix with soda, and then treat wish the R. F., for Ztl, Cfl, Sn. If a white coating is formed, test with cobalt solution. 45.

C. Treatment of the Third Portion, -— Dissolve some of the substance in S. Ph, on platinum wire in O. F., observing whether SIO is present or not, and test for ittft with nitrate of potassa. i 90.

4. Dissolve in S. Ph. on plati stance is not metallic and does Ch. with tin in the R. F. J 50.

S. Test for Se on Ch. g 99.

0, In absence of Se fuse with soda in the R. F. and test for S on silver foil. 107. In presence of Se test for S in open tube. J 107. (To distinguish between S and SO, see 108.)

y. Test for Hff with ry soda it

o.led by

Determination Of Compounds.

fuse Test

Mix some of the substance with i on Ch. in the R. F. Cupel the with nitric acid for Au. g 79.

3ssay lead and borax glass and lead button for Ag. 105.

9. Test for CI, Br, and I, with i oKide of copper. Jg 62, 63, 65.

I bead of S.

Ph. saturated i

vith

Test for d or Br with bisulpl

liate of potassa. J 63.

Test for no in a closed tube.

col 01

Test on platinum wire, oc in ation of the flame.

for

Test for C with hydrochloric acid.

Test for with bisulphale

of potassa.

19Z.

Test for Te in an open tube.

.,t.db,

Chapter Vi.

On the Determination of Minerals by means of the Blowpipe, aided by Humid Analysis.

By the methods given in the preceding chapters, we can readily detect the constituents of most inorganic com- pounds, whether prepared artificially or occurring in na- ture ; especially if heavy metals form the principal constit- uents. But these methods do not enable us to discriminate the different native siUcaCes, and other mineral bodies, which consist essentially of such substances as do not show any very characteristic reactions before the blow-pipe, as ex. gr. the alkaline earths. In some cases we may succeed in ascertaining the principal ingredients of the substance . under examination, but fail in establishing the mineral species. To attain this end more securely, we must pursue a course, composed of an examination of the physical properties of the body and of blow-pipe operations, aided by huraid analysis. The course adopted in this " Manual " is that given by Franz von Kobell, as laid down in his "Tafeln zur Bestimmung der Mineralien."

The minerals, according to Yon Kobell's system, are arranged in two large groups, the first embracing those possessing metallic Justre, the second those devoid of me- tallic lustre. To avoid mistakes, originating in the fact that some minerals occur sometimes with, and sometimes without, metallic lustre, these minerals will generally be found enumerated in both groups.

The same precaution has been taken in regard to those species in which the degree of fusibility, whether below or

o.led by

Determination Of Minerals. 147

above 5, might appear doubtful. The degree of fusibility is to be Judged of from the following scale :

1. dray Antimoiiy, — Fusible in coarse splinters in the flarac of a candle.

2. Natrolite.- — Fusible in fine splinters in the flame of

3. Almandlne or Iron Garnet — Easily fusible before the Blp.

4. AetiHOlite (a variety of hornblende). — Fusible be- fore the Blp. in coarse splinters.

5. Orthoelase. — Fusible before the Blp. in fine splinters.

6. Bronzite. — Fusible on the edges in very fine splin- ters.

The fusibility, when equal to that of actinolite, is desig- nated by 4 ; when between that of natrolite and almandine, by 2.5, and so on. See Appendix, page 296.

A list of the oxidized minerals, arranged according to their fusibility, may be found at the end of this chapter.

The two large groups are divided into classes accord- ing to their fusibility; these again into divisions, etc., by which means we obtain the following general classification :

GEOTTP I.— MIiraRALS WITH METALLIC LUSTRE.,,

CLASS I — Native malleable metals, aud mercury.

CLASS H— Fusibility 1—5, op readily volatile.

Division i. Give a strong arsenical odor on Ch.

Division 2. Give on Ch., or in an open tube, the horse- radish odor of selenium.

Division 3. Give in an open tube a white or grayish sublimate, which is fusible into colorless drops, indicative of tellurium. On charcoal a white coat- ing, and coloring the R. Fl. fiame green ; in pres- ence of selenium, greenish -blue.

o.led by

148 Determina Tion Of Minerals.

CLASS n.— PusibiUty 1—5, or readily volatile.

Division 4. Give antimonial fumes on Ch.

Division 5. Give with Sd. on Ch. a sulphur reaction, but do not give indications as above.

Division 6. Do not exhibit the properties of the preced- ing divisions.

CLASS m— Inflisible, or fusibility above 5, and not Yolatila

Division i. Give with Ex., in very small quantities, in

the oxidizing flame, the manganese reaction. Division 2. Treated on Ch. in R. Fl., become magnetic, Division 3. Resembling those of division 2.

GROUP n. — MINERALS WITHOUT METALLIC LUSTRE. / CLASS I— Easily volatile, or combustible. CLASS II — Fusibility 1—5; not, or only partially, volatile, PART I. Fused with Sd. on Ch. give a metallic globule or magnetic metallic mass. Division i. Give with Sd. a globule of silver. Division 2. Give with Sd. a globule of lead. Division 3. When moistened with hydrochloric acid, color the flame blue, and give with nitric acid a solution which, on addition of an excess of am- monia, assumes an azure-blue color. Section I. Give on Ch. a strong arsenical odor. Section 2. Give no arsenical odor. Division 4. Imparl to the Bx. bead a sapphire-blue color. Division 5. When fused in forceps, or on Ch, in R. Fl., give a black or gray metallic magnetic mass. Section i. Give on fusion on Ch.astrong arsenical odor.

o.led by

Determination Of Minerals. I49

Section 2. Soluble in hydrochloric acid without leav- ing a perceptible residue, and without gelatinizing. Section 3. With hydrochloric acid, gelatinize or de- compose, with separation of silica. Section 4. But little affected by hydrochloric acid. Division 6. Not belonging to either of the preceding divisions. PART II. Fused with Sd. on Ch., give no metallic globule, or magnetic metallic mass. Division i. After fusion and continued heating on Ch., in the forceps, or on platinum foil, have an alkaline reaction, and change to blue the color of moistened red litmus paper, or brown the color of turmeric paper. Section i. Easily and completely soluble in water. Section 2. Insoluble in water, or soluble with diffi- culty. Division 2. Soluble in hydrochloric acid without leav- ing a perceptible residue; some also soluble in water ; not gelatinized by evaporation. Division 3. Soluble in hydrochloric acid, gelatinizing, especially after partial evaporation. Section I. Giving water in a matrass. Section 3. Giving no water inanvatrass, oronlyatrace. Division 4. Soluble in hydrochloric acid, with separa- tion of silica, without gelatinizing. Section 1. Giving water in a matrass. Section 3. Giving no water in a matrass, or only a

Division 5. Little affected by hydrochloric acid ; im- parting to the Bx. bead the color of manganese. Division 6, Not belonging to either of the preceding

Ho.led by

Iso Determination Of Minerals.

CLASS m.— Infusible, or fusibility above 5.

Division i. After ignition, moistened witli SoCo. and

again ignited, assume a bright -blue color.

Section i. Giving much water in a matrass.

Section 2. Giving little or no water in a matrass.

Division 2. Moistened with SoCo. and ignited, assume

a green color. Division 3. After ignition have an alkaline reaction, and change to brown the color of moistened turmeric paper. Division 4. Completely soluble, or nearly so, in hydro- chloric or nitric acid, without gelatinizing or leaving a, perceptible residue of silica. Division 5. With hydrochloric acid, gelatinize or de- compose, with separation of silica. Section 1. Giving water in a matrass. Section 2. Giving no water in a matrass, or only a trace. Division 6. Not belonging to either of the preceding divisions. Section I, Hardness below 7. Section 2. Hardness 7, or above.

Group I. — Minerals With Metallic Lustre.

CLASS I — Native Malleable Metals, and Mercury. Native Silver, see g 197. Native Gold and Ekctrum (alloy of silver and

gold), see I 150. Native Copper, see § 134. Native Lead, characterized by coating on charcoal

(see § 23) and softness; 1.5. Native Platinum, see § 152.

o.led by

De Termina Tion Of Minerals. 1 5 1

Native Palladium, distinguished from the preced- ing by being soluble in nitric acid.

Native Iron, see § 154.

Native Mercury, see § iS7.

Argentite and Hessite are malleable, for which see Divisions 5 and 6.

CLASS H.— FusibUity 1 — 5, or readily volatile.

Division I. Give a strong arsenical odor on charcoal.

Native Arsenic, see § ii8.

Dufrenoysite, see § 170; Tennantiie, see g 139; Polybasite, see § 207; Domeykite, see § 140.

Binnile, As'S'. In the closed tube, give a sublimate of sulphide of arsenic ; in the open tube, a crystalline sublimate of arsenous oxide, with sulphurous fumes. Before the Blp. on coal give a faint white coating and odor of arsenic. Fuses to a globule, giving metallic copper with soda. Lustre, metallic ; color, black on fresh fracture; streak, cherry-red; brittle. 11 4.5. G=4.4.

Mnargite, sCu'S -[- As'S*. In closed tube, deciepi tates and gives a sublimate of sulphur In open tube, gives off sulphurous acid and arsenous o\- ide, the latter condensing to a sublimate con- taining often antimonous oxide The roasted mineral gives a globule of copper with fluxes. Lustre, metallic; color and streak, grayish-black; Brittle. Fracture uneven. H 3. G 4'4'

Algodonite, (Cu'/As'. H 4. 0=7.6. Whitneyite, (Cu')'As'. Less fusible than algoda- nite, otherwise as in domeykite. Massive. Crys- talline ; very fine granular. Lustre, dull, but strong metallic where scratched ; soon tarnishing.

o.led by

1S2 Determination Of Minerals.

CLASS n.— Fusibility 1 — 5; or readily, voMUe. Division i — {conii'nuid).

Color, reddish to grayish-wliite, becoming brown and black on exposure. Malleable. 11 3.5. G=8.2.

Smaltite, see 12S ; Cobaltite, see § 129.

Skutterudite, CoAs' ; Glaucodot, (CoFe) S' + (CoFe) As' ; Alloclasite, zCoS" + CoAs' + 4EiAs. Before the Blp., all give a sapphire-blue color to the borax bead. Decomposed with nitric acid, with separation of arsenous oxide forming a red solution. In a concentrated solution of alloclasite water, gives a cloudiness, but not in the others, Smaltite, skutterudite, and glaucodote, heated in a matras, give a sublimate of metallic arsenic. Cobaltite gives none. The strong acid and di- lute solutions of cobaltite and glaucodote give a precipitate with chloride of barium ; the solu- tions of smaltite and skutterudite none or a very small one. Smaltite has no cleavage.

Some varieties contain nickel and resemble chloanthite, in which case the nitric acid solution is green. The nickel varieties are distinguished by decomposing the powdered mineral with nitric acid, neutralizing with ammonia without filtering, and afterward, without diluting, filtering. The filtrate will have a fine blue color.

Compare the following minerals, also native bismuth, which often contain cobalt.

Niccoliie, see § 191 ; Gersdorffile, see § 192 ; Chlo- anthite (var. of Smaltite), NiAs', distinguished from gersdorffite by not giving the reactions for sulphur.

o.led by

Determination Of Minerals. Is3

Sammelsbergite, NiAs' (similar to chloanthite). In closed tube, give a sublimate of metallic ar- senic. See also Corynite, NiS= + Ni,(Sb, As)S', which before the Blp., on coal, give the smell of arsenic and fumes of antimony. Color, silver- white to steel-gray. See UUinannite. Arsenical Pyrites, see § i6i.

Compare also native bismuth, native antimony, which often contain arsenic, but are easily recog- nized by the white or yellow coating on coal. Proustile often has metallic lustre, but is recog- nized by its red streak. Division 2. Give on charcoal, or in an open tube, the horse-radish odor of selenium. Tiemannite, HgSe, Lehrbachite, Hg (PbSe); sele- nide of mercury and lead yield metallic mercury on being heated with Sd. in a closed glass tube (§ 91) ; the latter yields a globule of metallic lead on being heated on charcoal with Sd. Clausihalits,V\:&. Color, lead-gray; volatilewith- out previous fusion, depositing first a slight gray, then a white, and finally a greenish -yellow coat- ing; with Sd. yields with difficulty globules of

.Naumannite, AgSe. Color, iron-black; melts readily, and yields with Bk. a globule of pure silver, Berzelianite Cu'Se and Eucairite, Cu'Se + AgSe. Color of the former, silver-white ; of the latter, lead-gray. Distinguished from theotherminerals of this division by giving copper reactions. Crookesite, (Cu'TlAg)Se, is similar, containing 18

o.led by

154 Determination Of Minerals.

CLASS H.— Piisibillty 1—5, or readily volatile.

Division 2 — {continued).

per cent, of thallium, and coloring the flame bright -green, Zorgite, PbSe -f- CuSe. , colors the flame blue. Division 3. Give in an open tube a white or grayish sub- limate, which is fusible into colorless drops, in- dicative of tellurium, see § 11.

The assay-piece used for this experiment ought not to be very small. It must also be borne in mind that the minerals of this division frequently evolve an odor of selenium, owing to a small per- centage of selenium which they contain as adven- titious constituent.

The minerals of this division may be subdivided ac- cording to their color.

a. Oresof tellurium of tin-whiteorsi!ver-whitecolor.

Native Tellurium, fuses readily and is volatile with- out leaving a residue.

Hessite, AgTe, and Altaite, PbTe ; both soluble in nitric acid ; the former yields with Sd. on Ch. a globule of metallic silver.

Some varieties oi Sylvanite, see § 151.

d. Ores of tellurium of lead-gray or steel-gray color.

Tetradymite, see § 123.

Sylvanite, see § 151.

Nagyagite, Pb., An., Te., S. Color, blackish lead-gray. Distinguished from the preceding by its solution in nitric acid giving a copious pre- cipitate with sulphuric acid. Division 4. Give copious antimonial fumes on charcoal (see § 16) with a pure white coating, and give no color to the R. Fl.

o.led by

Determination Of Minerals. 15S

The fumes possess sometimes the odor of sulphurous acid or arsenic. N'aiive Antimony, distinguished by its tin-white color; .Sft'iwiVff, see § 115; ZmiemU, stt i-jo ; Jamesonite, see § 170 ; Bournonite, see § 170.

The powdered stibnite, on being treated with hydrate of potassa, assumes a yellow color, while the latter three minerals, which are steel-gray, do not change color. Bournonite, on being treated with nitric add, imparts to the solution a sky- blue color, and gives copper reactions on being treated as described in § 71. Stylotypite is similar to bournonite, but no precipitate is formed with sulphuric acid from its solution in nitric acid. Zinkenite and jamesonite are converted into white powders by treatment with nitric acid with- out imparting a color to the acid ; they are dis- tinguished by their hardness, that of zinkenite being 3.5, that of jamesonite, z.5. The former has no cleavage, while in the latter it is very marked in one direction.

Closely resembling the above in their chemical behavior are the following rare minerals : Bmtlan- gert'U, see ijo ; Geocronite,%ei I 170; Plagi- onile, see § 170; Menegheniie, see § 170. Discrasite, see § 198; Stephanite, see § 206; some varieties of Tetrahedrite, see § 138; Miargyriie AgS, Sb'S'. Discrasite does not give a sulphur reaction, all the others do. Tetrahedrite gives a copper reaction on being treated as described § 73- Miargyrite, streak, dark cherry-red ; stephanite, streak, black. Miargyrite and steph- enite, hardness, 2.5 ; tetrahedrite, hardness, 3.5.

o.led by

156 De Termina Tion Of Minerals.

CLASS n. — Fusibility 1—5, or readUy volatile. Division 4 — [continued').

All the minerals of this subdivision give a globule of silver on being treated as described § 104 or § loS-

Bragniardite, Sb'S", AgS, PbS. Isometric. Treated with nitric acid precipitates sulpbate of lead.

Freieslebefiite, 5(Pb,Ag)S4-2SbS', behaves in the same way, but is monoclinic. Compare also Py- rargyrite.

Ca/fjA'iVf [An timonial Copper], Cu'SjSb'S'; does not give a globule of silver, but yields a globule of metallic copper on being treated with Sd. on charcoal.

Ullmanmte, see § 193; Berthierite, see § 116; Breithauptite, Ni, Sb. All yield a magnetic glob- ule with continued heat. Breithauptite is distin- guished from the other two by not giving a sul- phur reaction. Division 5. Give with Sd. on Ch., a sulphur reaction, but do not give the general reactions of the pre- ceding divisions.

Silver Glance, § 203 ; Jalpaite, § 203 ; Acanthite, § 203.

Galenite, see § 169.

Cinnabar, see § 190.

Alabandite,'Hi'aSi. Isometric. H=4 — 4.5. Color, iron-black ; streak, green. Lustre, snbractallic. The pulverized mineral evolves sulphuretted hy- drogen with hydrochloric acid.

Hauerite, MnS H 4. Color, brownish -black; streak, brownish-red. Listre, metal lic-adaman -

o.led by

nBTBSMINATION OF MINERALS. 1ST

tine. Yields sulphur on being heated in a matrass. These manganese minerals, mixetl with phosphorus and saltpetre and boiled, give a fine violet solution.

ChaUocite, see g 137; Stromeyerite, see § zo8 ; Sianrdte, see § zio; Chalcopyrite, see § 135; Bornile, see § 136; Cubanite, Cu'S, Fe'S; Witiickite, sCu'S, BiS; Aikinite [Aciculai Bis- muth], 3Cu'S, Bi'S= + 2(3PbS, Ei'S'); Grunauite, Bi'S' + loNi'S'; Cuproplumbite, Cu'S, aPbS. Fentlandite, NiS, zFeS. All these minerals are partially soluble in nitric acid, the solution pos- sessing a sky-blue or green color ; on addition of water to the concentrated solution-a white pre- cipitate is produced, if the mineral under exami- nation was wittichite, grunauite, or aikinite. [To distinguish these three, add to the acid solution sulphuric acid ; a precipitate indicates aikinite ; wittichite gives the copper reaction on being treated as described in § 73, grunauite not.] Copper pyrites and cuban are distinguished from the others by their brass-yellow color; purple copper is also characterized by its color. To distinguish the remaining four minerals, make a solution in nitric acid ; add sulphuric acid : a precipitate indicates cuproplumbite; if no pre- cipitate is produced, add hydrochloric acid : a precipitate indicates stromeyerite; to distinguish between copper-glance and tin pyrites, see § 137 and § 310.

MiUerite,?: § 194; Linnmite,%&G.% \'3fi; Pyrite, seei$S ; Marcasi/e, set 15; FyrrAoiiU, §160; Stembergite, S, Ag, Fe. The members of this

o.led by

Is8 Determination Of Minerals.

CLASS n. — Fusibility 1—5, or readily volatile.

Division 5 — {continued).

subdivision fuse to globules which are attracted by the magnet. They are readily distinguished by the characteristics given in Chapter III. Sternbergite, by the treatment described § 104, yields a globule of silver. Marcasite and pyrite can only be distinguished by their crystalline form.

Bismulkinite, see § 125 ; Chiviatite, % 125. Division 6. Do not exhibit the properties of the preced- ing divisions.

Amalgam, see § 188; Arguerite, § 188.

Native Bismuth, see § 122.

Hematite, see § 156.

Cuprite, see § 142. Often wJth weak metalliclustre.

Magnetite, see § 157.

Wolframite, MnO, FeO, WO. H 5—5.5. G=7.i — 7.5. Orthorhombic. Lustre, sub- metallic. Streak, dark reddish-brown to black. Opaque. Sometimes magnetic. Color, dark- grayish or brownish -black. Fusibility, 3, The pulverized mineral on being boiled with aqua regia assumes gradually a yellowish color.

Samarskite, NbO', FeO, U'0% VO, W0% ThO', ZrO', MnO, CoO, MgO, CaO, HO. Color, velvet-black. Lustre of surface of fracture, shining, and stibmetallic. Streak, dark reddish- brown. Fusibility, 4.5. By fusing the pulver- ized mineral with hydrate of potassa, in a silver crucible, boiling the fused mass in water, it gives a green solution, which is filtered ; hydrochloric acid gives a white precipitate. If this is boiled

o.led by

DETERMINATION OF MINERALS. IjQ

with concentrated hydrochloric acid and tin for a few minutes, an equal volume of water added, it gives a bright blue solution.

Rkodomte, dark varieties, 3MnO.SiO 3HO.

Yields water on being heated in a matrass.

Soluble in hydrochloric acid, with separation of

silica. In O. Fl. , colors the borax glass amethyst.

Compare KHpsteinite.

SoKie varieties of Psilomelane, see § 183.

Fayalite, Lievrite, and Allanite, some varieties, see p. 169.

Flattnerite PbO', Color, iron-black ; lustre, metal- lic-adamantine ; streak, brown ; opaque ; easily reduced to metallic lead.

CLS M.— Infusible, or fusibility above 5.

Division i. Give with borax, in very small quantities in the O. Fl., the manganese reactions.

The members of this division are distinguished from each other principally by their physical properties. Braunite, see § 182; Hausmanntte, see § iSi Psilomelane, see § 183; Pyrelusite, see § 180 Franklinite, some varieties, see § 1 86 ; Manganite Mn*0', HO. Color, steel-gray to iron-black streak, dark reddish-brown ; hardness, 3 — -4.

yields water In a matrass. Crednerite, sCuO, aMnW. H 4.S- Lustre, metallic ; color, iron-black to steel-gray ; streak, brownish - black. Moistened with H, CI., gives a fine blue before the Blp. Dissolved in H. CI. with ammonia, a precipitate and blue solution, which is not the case with the foregoing.

o.led by

l6o DETERMINA TION OF MINERALS.

CLASS in .— Intusible, or fusibility above 5. Division I — [continued').

Compare also Alabandite and Hauirite. Division 2. Heated on charcoal in reduction flame, be- cotne magnetic.

Hematite, sec § 156.

Franklinite, see § 186; Magnetite, see § 157.

Titaniferous Iron, see § 162; some varieties of Sutile and Brookiie (see below) ; some varieties of Limonite (§ 155), and Blende (§ 212). Division 3. Minerals resembling those of Division 2.

Chromite, see § 127,

Molybdenite, MoS'; Graphite, C, see§ 216. Both very soft; liardness, 1.5. Molybdenite, when heated in the forceps, colors the flame greenish ; and gives a sulphur reaction when treated as described in § 107.

Brookiie, TiO'; orthorhombic. Ferofskite, CaO. TiO ; isometric. Both give the reaction for tita- nium as described § iii. Distinguished by crystalline form.

Iridosmine, see § 153.

Tantalite&t Columbite, MnO, FeO, TaOS NbO, WO', SnO Yttro-tantalite, 3CCaO.YO.FeO), CTaO", WO"). The color of these minerals is iron-black ; yttro-tantalite loses its color before the Blp. and becomes yellowish or white, that of the others remains unchanged. Acids affect them but little. Tantalite and columbite give the same reaction as samarskite when treated with hydrate of potassa, etc. (See p. 158.) Compare Poly erase and Aeschyniie. Uraninite, UO, U"0'. Color, usually velvet-

o.led by

DETERMINATION OF MINERALS. l6l

black; lustre, greasy; partially soluble in nitric acid -to a yellow liquid ; the solution gives a aul- phur-yeliow precipitate with ammonia. Boiled with phosphoric acid gives an emerald-green solution.

OaOCP II. — MINERALS NOT POSSESSING METAL- LIC LUSTRE.

CLASS I. — Easily volatile or combustible.

Native Sulphur, S. Completely volatile; burns with a blue flanie and emission of sulphurous acid. Color, sidphur-yeliow, honey-yellow, and grayish and brownish from impurities.

Realgar, see § 1 19 ; Orpiment, see § 120.

Arsenolile, see § 121 ; Kermesite, see § 117.

Vakntinite, SbO'. Orthorhombic. Color, white ; strealc, white ; does not change color with hy- drate of potassa; does not evolve sulphuretted hydrogen with hydrochloric acid. Lustre, ada-

Senarnwntite, SbO°. Isometric. Lustre, resinous, inclining to sub-adamantine ; streak, white.

Sal-ammoniac, NH*C1; Ma.seagHite,VV-0,ZO HO. Color, white; both evolve ammonia with hydrate of potassa; the- former is volatile with- out previous fusion, the latter intiimesces.

Cinnabar, see § 190; Calomel, see § 189.

Cotunnite, PbCl. Color and streak, white. Fuses easily on coal; volatilizes, and gives a white coat, the inner edge of which is tinged yellow; with soda, globules of metallic lead.

o.led by

l62 DETERMINATION OF MINERALS.

CLASS n.— Fusibility 1—5 ; not, or only partiaJly, volatile.

PART I. Give with carbonate of soda on charcoal a metallic globule or a magnetic metallic mass. Division i. Givewithcart>onateof sodaaglobuleofsilver.

Proustite, see § 205 j Pyrargyrite, see § 204 ; Xanihoconite, sAgS + As'S'+ aCsAgS, As'S'), be- haves liie proustite, from which it is distinguished by its yellow streak. Compare Myargyrite.

Cerargyriie, see § 199 ; lodyrile, see § 202 ; Embo- lite, see § zoo.

Seldite, AgO, CO', dissolves in nitric acid with effervescence. Color, ash-gray to black. Division 2. Give with carbonate of soda a globule of lead. The minerals of this division are all soluble in nitric acid ; the solution gives a copious precipi- tate with sulphuric acid. If dissolved by boiling with caustic potassa, chromate of potassa directly, or on addition of acetic acid, gives an orange precipitate.

Bindheimite, gPbO, SbO' -)- 4HO. Lustre, resinous or dull. Color and streak, white, grayish -yellow. Before the Blp., on coal, gives a coating of lead and antimony, in the matrass water.

Mimetite, PbCl-|-3(3PbO, AsO) ; Hedyphane, Pb CI + 3{3[PbO.CaO], [AsO'.PO']). The former completely, the latter partially reduced to metal- lic lead with evolution of arsenical fumes.

Pyromorphife, see § 175.

Minium, sec 168; Croeotte, see § 177; Phmni- cochroite, 3PbO, aCrO'. Dechenite, (PbO, ZnO;)VO', often with AsO=. Crocoite and phcenicochroite give the chromium reaction (§ 67). The latter three, on being boiled with

o.led by

Determination Of Minerals. 163

hydrochloric acid, give an emerald-green solu- tion ; on adding alcohol to the liquid, concen- trating by heat, pouring off from the residue, and then adding water: the liquid assumes a slsy- blue color if the mineral was dechenite. The streak of crocoite and dechenite is reddish-yellow, and that of phcenicochroite brick-red.

Linariie, PbO.SO= + CuO.HO is characterized by its deep azure-blue color. The color is destroyed by digesting with nitric acid, and sulphate of lead is precipitated.

Cerussite, see § 172 ; Phosgemfe, see 171 ; Lead- MlUte, see § 1 73. Susanniu is of similar compo- sition, but is hexagonal. Lanarkite, PbO.CO°-|- PbO.SO All soluble in nitric acid with efferves- cence ; leadhillite and lanarkite leave an insol- uble residue of lead. The solution of phosgeniie gives with nitrate of silver a precipitate of chlo- ride of silver.

Mendipite, PbCl + aPhO ; MaUockite, PbCI + PbO. Dissolve in nitric acid without efferves- cence ; the solution gives aprecipitate with nitrate of silver. Colorless; white

Anglesite, see § 174.

Wulfeniie, see § 179.

Stohiie, PbO, WO'. Color, yellow, yellowish- brown; lustre, resinous. Soluble in abundant quantity of hydrochloric acid, leaving a yellow- ish-green residue (WO). With sulphuric acid the pulverized mineral assumes a bright lemon- yellow color.

Vauquelinite, see § 1 78 ; Vanadinite, 3 PbO, VO' with PbCI. Hexagonal. Color of the former blackish -green, olive-green ; of the latter brown,

o.led by

164 Determination Of Minerals.

CLASS II." FnaihiUty 1—5 ; not, or only partially, volatile, Division 2 — {continued').

yellowisli. Both impart to the borax bead an emerald-green color. Both are soluble in nitric acid. The solution of vanadinite is yellow, and gives a precipitate with nitrate of silver- That of vauquelinite not. Descloizite, t PbO, VO'. Orthorhombic. Division 3. When moistened with hydrochloric acid, color the flame blue ; and give with nitric acid a solu- tion which, on addition of an excess of ammo- Section I. Give on charcoal a strong arsenical odor.

Chenevixite, Fe'O', AsO= + sCuO, HO. Lustre, vitreous. Color, dark-green. Streak, yellowish- green. Fuses to a black magnetic slag, while the following do not.

Bayldonite, 4CPbO, CuO)AsO= -f 2 HO with PbO. Lustre, resinous. Color, green. Dissolved in nitric acid, gives a precipitate with sulphuric acid of sulphate of lead.

Olivenite, see § 147.

TyrolUe, see § 148; ChakophylUte, 8CuO.AsO' + 12HO. Color, green. Both decrepitate vio- lently and yield much water ; chalcophyllite dis- solves in ammonia without leaving a residue.

Conichalcite, sCCuO, CaO), (AsO PO') -f CuO, HO -f- |H0. Fused, gives an alkaline reaction.

Liroconite, AsO*, P0>, CuO, APO', HO. Color, sky-blue. Does not decrepitate; loses 22 per cent, of water on ignition.

Euchroite, 4CuO.AsO' -i- 7HO ; Erinite, sCuO.

o.led by

Determination Of Minerals. 165

AsO -j_ 2HO. Color of botli emerald-green. The former loses by ignition i8J jjer cent, of water, the latter only 5 per cent. Ermite, amor- phous. CornmalUte, also amorphous, contains 13 per cent, of water. Section 2. Do not give an arsenical odor on charcoal.

Atacamife, see § 141. Tallingiie and Percylite.

Chalcanthiie, see § 145 ; Brochantite, 2(3CuO.SO0 -H CuO, HO -I- 4HO ; Cmellite, CuS. These three minerals give a sulphur reaction (g 107); chalcanthite is soluble in water, the other two not. Color of covellite, dark indigo- blue; of brochantite, emerald -green, with iz per cent, of water, Langite, greenish-blue color, with 16 per cent, of water.

Cuprite, see § 142 ; Melaconite, CuO. Color, dark steel-gray to black. Both dissolve readily in acids without effervescence (except impure varie- ties of melaconite).

Malachite, see § 143 ; Anurite, see § 144 ; Mysorin, CuO.CO Color, blackish-brown; does not yield water in a matrass. AH three dissolve readily in acids with effervescence. Aurichalcite gives a zinc coating on coal. Atlasite, dissolved in nitric acid, gives a precipitate of chloride of silver with nitrate of silver.

PseudamalachitejZee % 146 ; Lihetheniie, 4CuO.PO -|-HO; Lunnite, eCuO.PO* + 3HO; Ehlite, 5CiiO.PO+3HO ; Tagilite, 4CuO.PO + 3HO. Are all readily soluble in nitric acid without effervescence ; the (slightly acid) solution gives a precipitate with acetate of lead. Pseudomala- chite loses 14 per cent, of water on ignition, the

o.led by

I66 Determination Oe Minerals.

CLJS IL— Fusibility 1—5 ; not, or OBly partially, volatile. Division 3 — {continued).

others less (from 7 to 10 J). Libethenite is daik olive-green ; ehlite, and tagilite, emerald -green. Torbemite, aCU'C) P0= + CuO.HO + 7HO. Color, etnerald-green. Dissolves in nitric acid to a yellowish-green liquid ; on addition of am- monia in excess, a bluish-green precipitate is formed, the supernatant liquid being blue. Volborthite, (CuO, CaO)',VO' + HO. Division 4. Impart to the borax bead a blue color.

Erythrite, see § 131 ; Annabergite, see § 196. Division 5. When fused in the forceps or on charcoal, in reduction flame, give a black metallic magnetic

To observe well the magnetic character of the fused mineral, it is advisable to expose a pretty large assay-piece to the action of the reduction

Section I, Evolve a strong arsenical odor on being fused on coal. Scorodite, see § 166; PitHcite, Fe'O', AsO= + Fe'O', SO' 4- isHO; BsudanHte, Fe', PbO, CuO, HO, SO', PO=, AsO'. The pulverized minerals assume with hydrate of potassa a red- dish-brown color. Scorodite and beudantite occur crystallized ; the first orthorhombic, and the second rhombohedral. Their color 19 usu- ally some shade of green — to brown and black. Streak, greenish-gray to yellow. Lustre, vitreous. Pitticite, massive and reniform. 2—3- Lustre, vitreous, sometimes greasy. Color, yel-

o.led by

DETERMINATIOl OF MINERALS. 167

lowish, brownish, blood-red, and white. Streak, yellow-white. Translucent -opaque. Arseniosiderite, 6CaO, AsO' + (4Fe'0', AsO) + 15HO, Color, yellowish -brown ; fibrous ; lustre,

Morenosiie, NiO, SO' -f 7HO. Partly soluble in water ; the solution assumes a blue color on ad- dition of ammonia. Section 2. Soluble in hydrochloric acid without leav- ing a perceptible residue, and without gelatin- izing. Give no arsenical odor when fused on

Pettkoite, 3FeO, Fe'C -j- 2SO', with 1.5 per cent.

water. Ha.s- Isometric. Lustre, bright. Color, pure black. Streak, dirty-greenish. Taste, sweetish,

Melanterite, see § 164; Botryogen, sFeO, aSO' + 3CFe=0', 2S0') + 36HO. Melanterite and bo- tryogen are soluble in water,, the latter leaving a yellow residue. The solutions give precipitates with chloride of barium ; also with ammonia. Streak of melanterite is green ; of botryogen, yellow, Rcemerite, yellowish-brown. Coquim- bite, Jarosite, and Fibrofeifite, ail yellow. The last, fibrous and silky, behaves similarly to botry- ogen. Voltaite is distinguished from the fore- going by its black or dark-green color, resinous lustre, and octahedral crystallization. All these sulphates, when heated in the closed tube, give much water.

Siderife, see § 163.

Hureaulits, 5(MnO, FeO) PO + 5HO. H 5, Triplile, 3(FeO, MnO)PO= + CCaMgre)F- H

o.led by

Ids Determination Of Minerals.

CLASS II.— Fusibility 1—5; not, oronlypartially.voktilft Division i~- {continued),

4 — g.g. Fuse readily; moistened with sul- phuric acid give the phosphoric add reaction (§ 35); ''th borax strong manganese reaction; hureaulite yields iirnch water ; triplite none, or very little.

Triphyliie, 3[FeO, LiO, MnO], PO=, shows a sim- ilar behavior; the manganese reaction is less decided. On dissolving the mineral in hydro- chloric acid, evaporating the solution to dryness, adding alcohol, heating the alcohol to ebullition and. burning the vapor, the flame assumes a pur- ple color. Zwieselite, a clove-brown variety.

DiadocUte, sFe'O', zPOHaFeO', 2SO'+32HO. H 3. G 2.03. Reniform or stalactitic. Lustre, resinous to vitreous. Coior, yellowish- brown. Streak uncolored. Soluble in hydro- chloric acid. When ignited, gives off sulphuric acid.

Vivianite, see § 165; Dufrenite, aFe'O'.PO' + 3HO; Cacoxenite, aFe'O.PO+iaHO; -ff.!V- He, sCsCaO, FeW)2P0=-f isHO. Fuse readily, and behave with sulphuric acid like the preced- ing ; give no manganese reaction. Yield much water in a matrass : cacoxenite, 33 per cent. ; vivianite, 28 per cent. ; borickite, 19 per cent. ; dufrenite, 8i per cent. Color of dufrenite, leek- green ; of cacoxenite, ochre-yellow; of vivianite, various shades of blue; of borickite, reddish- brown. Beraunite is a similar phosphate of red color.

o.led by

Determination Of Minerals. 169

Hematite, see § 156. Section 3. With hydrochloric acid gelatinize, or are readily decomposed with separation of silica,

Cwj;'eaVV<;,(i(FeO.MnO)'+Fe'0')SiO'+|HO. H 3.g. Rhombohedral, also amorphous. Color, black ; streak, dark leek -green ; yields water ; gelatinizes with hydrochloric acid. Side- roschisolite is probably a variety.

Smpnomelane, (3FeO(Al'0=, Fe'0=)3SiO' + 2HO. H 3.4. Chakodiie is similar in composition, often in velvety coatings of brass-like lustre. The color of these minerals is black, yellowish, and greenish-brown. Their streak is greenish- gray.

Veigtite and Ekmannite are closely related to the above. They are mica-like in aspect and struc- ture,

Palagonite, of brownish-yellow color and streak ; amorphous; yields water and fuses to a black magnetic glass. See aha Jollyte.

Hvaite, KCaO, FeOy + |(Fe'0", APO')' 2SiO= ; AUanite, -(CeO, FeO, LaO, DiO, YO)' + (AlW, Fe'OO'aSiO Yield no water, or only a trace ; gelatinize with hydrochloric acid ; allan- ite fuses with intumescence to a voluminous brownish or blackish glass; ilvaite intumesces but slightly, decrepitates, and fuses to an iron- black bead. Hardness of each, 5.5 — 6,

Fayalite, zFeO, SiO*. H 6.5. Lustre, metal- loid; somewhat resinous in fracture. Color, black, greenish, or brownish-black. Easily fusi- ble, gelatinizes, and attractable by the magnet.

i'JVTOMrt/(Vf,(HO-|(FeO,MnO,FeC!))'Si0and

o.led by

170 DETERMmATION OF MINERALS.

CLASS IL— Fusibility 1—5 ; not, or only partially .volatile. Division {continued).

Astrophyllite, containing titanium and some- times zirconium, are decomposed by hydrochlo- ric acid, with separation of silica, without gela- tinizing. Fusibility, 2 — 2.5 Pyrosmalite gives the chlorine reaction (§ 65) ; astrophyllite, not. The hydrochloric acid solution of the latter gives the reaction for titanic acid.

Lepidomelane, i(KO, FeO)' -f J(A1'0', Fe'O")' 3SiO'. H 3. Lustre, adamantiue. Color, black, with occasionally a leek-green reflection. Streak, grayish -green. Easily decomposed by hydrochloric acid, depositing silica in scales.

Andradite [Lime Iron Garnet], J(CaO)-|-}(Fe'0', Al'0')'3SiO'. Gelatinizes imperfectly ; fuses readily ; distinguished from the preceding by absence of cleavage. Color, green, brown, black.

Gillingite ; Xyloiils \y.\xne.t' of Serpentine\. Fuse with difficulty ; do not gelatinize. The former is black, amorphous; the latter brown, fibrous, woody. Both yield water in a matrass.

Some impure varieties of Limonite, see § 155. Section 4. But little affected by acids.

CrocidoUte, 6(NaO, MgO, FeO), 5SiO=+ 2HO; Fusibility, 1,7—2. Color of crocidolite, laven- der-blue or leek-green ; fibrous ; yields water in a matrass ; arfvedsonite is black, and yields no

[See aiso Hornblende and Tourmaline, below, some varieties of which become slightly magnetic after fusion.]

o.led by

Determination Of Minerals. 171

Celadonite [Green Earth], Fusibility, 3 ; color, celandin e -green ; hardness, i; earthy.

Acmite, (,i(FeO, NaO)' + |Fe'0')3SiO' ; Babing- tonite, (|(CaO, FeO, MnO)' + iFe'0')3SiO'. Fusibility of the former, a ; of the latter, z.6 ; form a black lustrous slag. Both are cleavable.

Almandite [Iron Garnet], (KFeO)= + l(Al'O'))' 3SiO', Fusibility, 3; hardness, 7—7.5. Color, reddish-brown. Not cleavable. See also AUo- chroite.

Wolframite and Ferberite, WO", FeO, MnO. Color, black ; streak, brownish ; metallic vitreous lustre; boiled with concentrated phosphoric acid, a blue syrup, which, diluted with water, becomes colorless. If powdered iron is added and then shaken, it gives a fine blue color.

Megabasite, mainly MnO, WOS behaves in a simi- lar manner. Streak, ochre-yellow.

Rhodonite, MnO, SiO'. H 5.5—6. Color, brownish-red to flesh-red. Streak, while. Often magnetic after fusion. Colors borax bead ame- thyst.

Lepidolite, often becomes magnetic on fusing, and colors the flame reddish-purple. Compare Epi- dok. Color, pistachio-green.

SHlpnomelane. With difficulty decomposed by hydrochloric acid. FusibiUty, 3. Color, black. Yields water in a matrass. Compare Lepidome-

Division 6. Not belonging to either of the preceding divisions. Molybdite, MoO'. Color, sulphm'-yellow ; earthy. Gives with the fluxes the reactions of molybdic

o.led by

173 Determination Of Minerals.

CLASS n.— Fusibility 1—5 ; not, or only partially, volatile.

Division ()—'{conti?iued').

acid. Dissolves readily in hydrochloric acid ; the solution is colorless, but turns blue on being stirred with an iron spatula.

Eulytite, 4BiO', gSiO'. Fuses easily to a brown bead. Gelatinizes with hydrochloric acid. On charcoal, with soda, yields a globule of metallic bismuth. Color, brown to yellow.

Bismutite, see § 124- PART H. With carbonate of soda on charcoal, give no metallic globule or magnetic metallic mass. Division i. After fusion and continued heating on char- coal in the forceps or in the platinum spoon, have an alkaline reaction, coloring moistened turmeric paper reddish-brown, and change to blue the color of a moistened red litmus paper. The test may be made with splinters and not with the powder. Section i. Readily and completely soluble in water.

Nitre, KO.NO*; Soda Nitre, NaO.NO'. Defla- grate vividly on burning coals. Fused on plati- num wire, the former colors the flame bluish, with a red tint ; the latter, bright-yellow.

Natron, NaO.CO'+ loHO ; Trona, 2Na0.3CO' -f- 4HO. The watery solution has an alkaline reaction, and effervesces on addition of hydro- chloric acid. Crystals of the former decompose quickly in the air, the latter not.

Mirabaliie, NaO.SO' 4- loHO ; Thenardite, NaO. SO'; Glaserite, KO.SO'; Epsomite, MgO.SO' + 7HO; Kalinite, KO.SO' + ATO'sSC + 24HO. The watery solutions of these minerals

o.led by

Determination Of Minerals. 173

give a copious precipitate with chloride of ba- rium; the solution, of potash, alum, and epsom- ite are precipitated by carbonate of potassa (dis- tinguished by reaction with solution of cobalt, g 44). Kainite, aMgO.SO" + KCl + 6H0, behaves in a similar manner; soluble in water, and a precipitate is formed with nitrate of silver. The concentrated solution of glaserite gives a precipitate with bichloride of platinum; mira- balite yields much water, thenardite none. Halite, NaCl ; Sylvite, KCl. The watery solution gives a copious precipitate with nitrate of silver. Gives also the reactions for chlorine described §§ 65, 66. The latter gives a heavy yellow pre- cipita.te with solution of platinum, but the former

Borax, NaO.aEO'-l- loHO. Gives the reaction for boracic acid, § 60. Section a. Insoluble in water, or soluble with diffi-

Hayesine, CaO, 2B0'+ 6H0. FusibUity, i ; coU oring the flame yellow. Yields much water. Moistened with sulphuric acid, the flarae changes momentarily to green. Somewhat soluble in hot water, giving alkaline reaction. The reactions of Ulexite are the same.

Gay-Lussite, CaO.COHNaO.CO'+sHO ; With- mVf,BaO.C0'; sCaO.PO+CaO.CO'. Dissolve in dilute hydrochloric acid with effer- vescence; the first yields water, the latter do not. The solution of the stafFelite gives a pre- cipitate with ammonia, the others not. Com- pare Sironiianiie, wlilch colors the flarae c

o.led by

174 Determina Tion Of Minerals.

CLASS n. — Fusibility 1 — 5 ; not, or only partially, volatile. Division i — {conHtmed').

Anhydrite, CaO.SO'; Gypsum, CaO.SO' + zHO; JPolyhalite, KO.SO' + MgO.SO' + 2(CaO.SO) -i- 2HO ; GlauberiU, NaO. S0= + CaO. SO'. Soluble in much hydrochloric acid ; in the solu- tion chloride of barium gives a precipitate. Gypsum yields much water, polyhalite little, the rest none; anhydrite is distinguished by superior hardness, 3.5 ; polyhalite is distinguished from glauberite by its solution giving a yellow pre- cipitate with bichloride of platinum.

Bariie, BaO.SO'; Cdestite, SrCSC. Insoluble in hydrochloric acid ; give a sulphur reaction when treated as described § 107. Celestite colors the flame red, §34; barite yellowish- green, g 35.

Fluorite, CaF ; Cryolite, sNaF -f A1=P ; Pharma- coliie, 2Ca0.3AsO 6HO. Do not effervesce with acids, and give no sulphur reaction. Phar- macolite evolves arsenical odor on charcoal ; the other two give fluorine reaction, § 76. Fusibil- ity of fluorite, 3; of cryolite, 1. AntosomtejVax. of fluorite, gives odor of antozone.

Chiolite, 3NaF -f aAl'F", behaves like cryolite; occurs only massive-granidar ; while cryolite is distinctly crystalline, and cleavable in three directions.

Pachnolite yields strongly acid water. Closely related are Arksutite and Chodneffite, without water ; ThontsenoUte and Gearksutite with water.

Cancrinite, (i(NaO, KO, CO)' fAPO')= sSiO' + fSiO' + NaO.CO'. Effervesces with hydro-

o.led by

Determination Of Minerals. I$

chloric acid, and gelatinizes. In tlie flame it grows white and opaque, and then melts (2.5), intumesces, and forms a white blebby mass. The easy fusibility distinguishes it from nephelite. Division 2. Soluble in hydrochloric acid without leaving a perceptible residue; some also soluble in water; not gelatinizing.

Tschmnigite, NH'O.SO'-I- APO'-sSO' + 24HO; Alunogen, Al'OsSO + 18HO; Goslarite, ZnO. SO" + 7HO. All soluble in water ; give sulphur reaction, § 107. Heated on chaicoal and treated with solution of cobalt, the former assume a blue, the latter a green color, §§ 44, 45- The first with caustic potassa gives the smell of am- monia, the second does not.

Chondrarsenite, sMnO, AsO* + 2H0. Easily fusible, giving arsenic fumes on coal, and ame- thyst color to the borax bead. Color, yellow.

Adamite, sZnO, AsO=+ZnO.HO. Easily fusible, giving arsenic fumes on coal, with a coating of zinc. Color, honey-yellow,

Struvite, NH'0,2MgO,PO= + 12HO. Melts easily. Yields water in matrass, with caustic potassa am- monia, and with hydrochloric acid fumes of chlo-

Sassolite,'&0'',2,B.O; Boracite,igO, 'QO'; Hy- droboracite, sCaO, 4B0'-f sMgO, 4iiO'-f 18HO. Give the boracic acid reaction, § 60. Sassolite is soluble in alcohol, the others not ; boracite yields no water, while the others do. Hydroboracite contains 26 per cent, water, and a similar min- eral, szaibelyite, 7 per cent. Sfassfurtite is closely related. Compare boras.

o.led by

176 Determination Of Minerals.

CLASS n.— Fusibility 1—5 ; not, or only partially, volatile. Division 2 — {continued').

Alabandite, MnS, and Hauerite, MiiS% give strong manganese reaction; see p. 115.

Wagnerite, MgF + jMgO.PO'; Apatite, sCaO.P 0' + iCa(Cl,F). Moistened with sulphuric acid, impart a pale bluish-green color to the flame, FusibOity of wagnerite, 3 — 3.5 (with intumes- cence) ; of apatite, 5 (without intumescence) ; wagnerite is soluble in dilute sulphuric acid; apatite not.

Brushite (f CaO + HO)'PO* 4HO, Behaves in the wet way like apatite, but yields 26 per cent.

Amblygonite [(LiO,NaO)' + APO'J'POs- Fusi- bility, 2 ; hardness, 6, With difficulty soluble in concentrated sulphuric or hydrochloric acid.

Torbernite (2U=0=)P0' + CuO.HO + 7HO. Au- tunite (2U=0')PO= + CaO.HO + 7HO. Fuse readily, yield water, and give with fluxes the re- actions of sesquioxide of uranium. See Table II. Soluble in nitric acid. The first gives a globule of copper with soda on coal. Division 3. Soluble in hydrochloric acid, forming a per- fect jelly. Section I. Givo water in a matrass.

Datolite (3CaO,3HO,BO>)SiO'. Yields but little water, and gives the boracic acid reaction, § 60.

Edingtonite, SiO',Al=0',BaO,etc. The dilute hydro- chloric acid solution gives a precipitate, with sulphuric acid, of sulphate of baryta. Sp. gr. a. 7.

Nalrolite, NaO,Al=0',3SiO'-|-zHO. Fusibility, 2 ; does not intumesce ; hardness, 55.5.

o.led by

Determination Of Minerals. 1/7

Scolecite, CaO,AI'0",3SiO' + 3HO ; LaunwnHte (i(3CaO)+JATO')3SiOH3HO. Scolecite, on being heated, curls up like a worm, and finally melts to a bulky, shining slag, which in the inner flame becomes a vesicular, slightly translucent bead; hardness, 5.5. Pyroelectric. Laumontite intumesces and fuses to a white translucent enamel; hardness, 3.

Nearly related to Scolecite, and showing a similar behavior, are Mesolite and Thomsonite, but they are not pyroelectric.

/'A//>/:i'f(|CaO+KO)ArO,4SiO',sHO.H, 4.3. Fusibility 3, with slight intumescence; occurs always in twin crystals. Lustre vitreous. Color white, sometimes reddish. Gismondite is closely related. Orthorhombic, with forms often re- sembling square octahedrons. H 4.5. Lustre splendent. Compare, in div. 4, Apophyllite, Okenite, and Anakite, which gelatinize with hydrochloric acid. Section 2. Giving only traces or no water in a matrass.

Helvite{\{JA.'aO,Y<y) + iBeO)SiO'+JMnS; Te- phroite, 2MnO,SiO'. Distinguished from the other minerals of this section by giving manga- nese reactions. Color of helvite, wax-yellow ; hardness, 6—6.5 ! of tephroite, ash-gray; hard- ness, 5.5 — 5. Danalite, containing zinc, gives with soda on coal a small slag of zinc, and with borax the iron reaction. Color, flesh-red to gray.

HoMynite and Lapis Lazuli, SiO'Al=0',CaO,NaO, SO,S, are of azure-blue color; give sulphur re-

o.led by

1/8 Detmrminatiok Of Minerals.

CLASS n.— Fusibility 1—5 ; not, or only partially, volatile. Division 3 — {continued').

action, § 107. Fusibility of the former, 4.5 ; of the latter, 3, forming a white glass.

Nosite and Skolopsite, SiO',Al=0',CaO,NaO,SO', of gray or brownish color ; give sulphur reaction, § 107. Fusibility of nosite, 4.5 ; of skolopsite, 3 (with intumescence like idocrase). The former crystallizes in dodecahedrons, the latter occurs granular-massive.

Sodalite, jNaCl + (3NaO)\SiO'_)= + 3((AP0') %\Qiy); Eudialyte, 2(CaO,NaO)2SiOHZrO aSiO give the chlorine reaction, § 65. The former fuses to a transi)arent, colorless glass, the latter to a grayish-green scoria or opaque glass. The dilute hydrochloric solution of eudialyte colors the turmeric paper orange-yellow ; boiled with sulphate of potassa, and evaporated to crys- tallization and then boiled with water, a precipi- tate of zirconia is formed which makes the solution cloudy. Wollastonite, CaO,SiO". Fuses quietly to a color- less, semi-transparent glass. The hydrochloric acid solution gives no, or only a very slight, pre- cipitate with ammonia ; but with the carbonate a bulky precipitate. See also Peciolite.

Nephelite (i(NaO,KO,CaO)' |Al'0')'3SiOH J SiO".

Melilite (§(NaO,MgO,CaO)' -)- ArO, Fe'O'/} 3SiO=.

With the solution of these minerals in hydrochloric acid, ammonia gives a precipitate. Meionite

o.led by

DETERMmATION OF MINERALS. I79

fuses with intumescence, the others quietly. Nephelite hexagonal, meUhte tetragonal (com- pare Cancrinite). The behavior of Barsowite is similar to melilite, but fuses with more difficulty, and quietly. (Compare Gehkniie, which is nearly infusible, and Zachylite.') Division 4. Soluble in hydrochloric acid, with separation of silica, without forming a perfect jelly. (It is sometimes necessary to treat the finely-pulveiized mineral with concentrated acid.) Section i. Giving water in a matrass.

Klisteimie, (MnO)'SiO + (2MnO)SiO=4-4HO. Easily decomposed by hydrochloric acid, evolv- ing chlorine. Fuses to a blaclc slag in the ox- idizing flame. With phosphoric acid it gives a violet solution.

Apophyllite, (HO,KO,CaOySiO'+HO,SiO. Pec- toUie (|CaO+JNaO+HO)SiOl Okenite, (JCa 0+iHO)SiO=+HO. The silica separates in the shape of gelatinous lumps. The hydrochloric acid solution gives no, or only a slight, precipi- tate with ammonia. Pectolite yields but little water, the others much. Fusibility of apophyl- lite, 1.5, forming a white vesicular glass; of okenite, 2.5 — 3, forming a porcelain-like mass. (Compare Xonaltite.')

Anakiie, NaO,AlW,4SiO',2HO. Gelatinizes like the preceding ; in the acid solution ammonia produces a copious precipitate.

Pyrosckrite (S(MgO)=-f Al=0')'SiOH3HO. Chon- icrite, CaO,MgO,FeW,Al=0',SiOHO. JoUyU, ((FeO,MgO)'+fAro')"3SiO'+4HO. Are dis- tinguished from the other minerals of this section

o.led by

1 80 De Termina Tion Of Minerals.

CLASS E— Pusibilityl— 5; not, or only partially .volatile. Division 4 — {continued').

by their inferior hardness, 2.5 — 3. Chonicrite fuses from 3,5 — 4, with intumescence; has qo cleavage ; whitish. Fusibility of pyrosclerite 4, without intumescence ; cleavable in one direc- tion ; green. Jollyte fuses with difficulty ; amor- phous ; brown ; powder light -green,

acterized by its hydrochloric acid solution giving a precipitate with sulphuric acid,

SiilMte, CaO,Al'OS6SiOS6HO. Hypostilbite, (JCa + |NaO),A10' + 44SiO=),6HO. Chabazile, |CaO-|-KNaO,KO),Al'0',4SiO=,6HO. /"/-fwaV (§CaO+|ATO'+K3H;oy,3Sio'. Fusewithintu- mescence to enamel-like masses. Prehnite yields but little water, losing by ignition only 4.3 per cent.; the others lose from ig to 20 per cent. Chabazite is distinguished by its rhombohedral crystallization and imperfect cleavage. In stil- bite and hypostilbite the cleavage is perfect in one direction. Stilbite is orthorhombic, and hy- postilbite occurs in radiate-fibrous or columnar masses. Mordetiite, H=5, occurs in hemispheri- cal, reniform, or cylindrical concretions, with a fibrous structure. Yields 12 per cent, water, and fuses without intumescence. Not perfectly de- composed by acids.

Mosandrite, (Ce,CaO,NaO,SiO',TiOSHO), and Catapleiite, have hardness 4 and 6, and distinct cleavage. The first fuses quietly to a yellowish- brown glass; fusibility 3.5 ; Catapleiite, 3, giv-

o.led by

DETERMINATION OF MINERALS. l8l

ing a white porcelain bead. It is soluble in hy- drochloric acid without gelatinizing, and gives the zirconia reaction, coloring turmeric paper orange-yellow.

&/w/(y [Meerschaum] (|MgO+HO)SiO'''+HO, see below; Deweylite, (§MgO+HO)SiO'+-|H O- Distinguished by being much less fusible than the preceding (fusibility, ;) ; the former absorbs water with great avidity, the latter not.

Sordavalite ((MgO,FeO)+ArO')3SiO'. Amor- phous, Fusibility, 2.5, forming a thick, black, brilliant glass. Color, brownish-black. Section 2. Giving only traces or no water in a matrass.

Cryophyllite. Micaceous. Fuses easily in the flame of a candle, giving the flame a lithia reaction.

Tackylyte, KO,NaO,CaO,MgO,FeO, etc. Fuses readily to a black, shining glass. Hardness, 6. 5 ; color, black.

Schorlomite, ((CaO)' + JyFe'O + -rdTiO')/

light; hardness, 5 — 5.5. Fuses with intumes- cence to a white, vesicular glass.

J(.M/V[f(NaO,CaO)'4-ZrO]SiO"[-fJgCFeO, MnO)CbO°]. Fusibility 3, forming a yellowish enamel. From the hydrochloric acid solution silica and columbic acid separate. EucoUie probably belongs here. With the fluxes gives the reactions of silica, manganese, and iron. Color, wine-, honey-, resin-yellow, brownish-red.

Labradorite (i(NaO,CaO) -f- |Al'0'y,3SiOH|Si

o.led by

183 Determination Of Minerals.

CLASS H— Fusibility 1—5; not, or only partially volatile. Division 4 — {continued').

bility, 3 — 4, without intumescence, forming a colorless glass. Hardness of the former, 6 ; of the latter, 6—7. Cleavage perfect.

Grossularite [some varieties], ((3CaO) + |(Ar C'sSiO*. Fusibility, 3. Not cleavable.

Tilanite [Spbene], some varieties, see below. Gives titanium reactions, §111. See Danburite, which gives a fine green flame. Also Tephroite, which gives an. amethyst color to the borax boad. Division 5. Little affected by hydrochloric acidj give with fluxes the manganese reactions.

curs only in radiated and stellated tufts. Color, straw-yellow. Silky. Yields water.

Spessartite [Manganese Garnet], ((MnO,FeO)'-|- APO'/3SiO Color, brownish-red. Fuses with- out intumescence. Not cleavable.

Fiedmontite, (KCaO)' + |(Al'0',Mn=0',Fe'0'))= jSiO'. Fusibility, a — 2.5 ; intumesces. Cleav- able. Color, cherry-red to reddish-black.

Rhodonite, MnO, SiO Fusibility, 3, without intumescence. Color, rose-red ; cleavable. Division 6. Not belonging to either of the preceding divisions. All are silicates except Scheelite, and are not decomposed, or only partially, by hydro- chloric acid.

Danburite, (i(CaO)' + |B0')' sSiO'. Fusibility, 3, and gives a fine green color to the flame. The bead is clear while hot, and cloudy when cold. Howlite is closely related.

o.led by

Determination Of Minerals. 183

Scheelite, CaO, WO'. Fusibility, 5. Soluble in Iiydrochloric acid, leaving a residue of tungstic acid, which is soluble in ammonia, and which gives with S. Ph. the characteristic reaction of tungstic acid ; see Table II.

Lepidolite, (sLiO.AFO'/ 3SiO'-|-2((LiO)', ATO=) 3SiO', and CookeiU, (SiO, KO, AFO', SiO", HO), are micaceous, splitting very easily in one direc- tion. Fusibility of lepidolite is 3, colors the flame crimson, and gives no water in matrass. Cookeite intumesces, colors the flame crimson, but yields much water in matrass.

TermophylUte, (SiO', MgO, HO), Euphyllite, and Margarite, are all micaceous in structure. The first intumesces before the flame and yields much water. The others fuse without intumescence (4 — 4.5J, and yield little water. Their laminte are not elastic. Euphyllite is easily decomposed by sulphuric acid, and margarite with difficulty. Compare Muscovite and Biotite.

Fetalite, (KLiO, NaO)' 4- |APO=) sSiO' + 3SiO', and Spodumejie, (LiO, NaO) + |A1=0') 3SiO=, do not possess as perfect a cleavage as the preced- ing, and greater hardness ; hardness of petalite, 6 — 6.g; of spodumene, 6.5 — 7. Both give the lithia reaction, § 89. Spodumene fuses with in- tumescence to a glassy globule ; petalite fuses to a white enamel.

Leucophanite fuses easily and quietly to a trans- parent and colorless glass. Cleavage very marked in one direction. H 3.5 — 4. If heated, phosphoresces with a reddish- violet light, also if struck with a hammer in the dark.

o.led by

184 Determination Of Minerals.

GLASS n.— Fusibility 1—5 ; not, or only partially, volatile. Division 6 — {continued').

Wilsonite. Fiasibility, 2, swelling up to a whitish glass. Yields water in matrass, H 3.

Sordavallite. Fusibility, z.5 ; amorphoiis; brown- ish-black. (See Div. 4.)

Diallage, (CaO.MgO), SiO'. Fusibility, 3.5; characterized by its pearly metallic lustre; cleaves easily in one direction.

Harmotome, BaO,APO',5SiO',gHO, Distinguished from most of the other minerals of this division by yielding water in a matrass. In the partial solution in hydrochloric acid, sulphuric acid gives a precipitate with the baryta. Occurs usually in twin crystals.

Axinite, (3CaO(Al'0', Fe'O, Mn'O', BoO')' sSiO"; Tourmaline, (3RO, R'O', BO")* gSiO'. (R NaO, CaO, MgO, FeO ;) A1=0", Fe'O'.) Give the reaction of boracic acid, § 61. Axin- ite fuses readily with intumescence to a dark- green glass. Different varieties of tourmaline show different fusibility. Hardness of axinite, 6.g; of tourmaline, 7— 7-5. Heat develops electricity in tourmaline, but not in axinite.

Pyroxene (var, MalacoUte'), (CaO, MgO)SiO', and (var. Augite), (CaO, MgO, FeO) (SiC, APO'|). Their H=6. Fusibility, 3,5 — 4. Malacolite fuses to a whitish, augite to a black glass. Color of augite, black or dark-green ; of mala- colite, pale-green or colorless.

Var. Hedenberte, (CaO, FeO,) SiO=.

Amphibok (var. TremoUie), (CaO, MgO.)SiO=;

o.led by

DETERMINATION OF MINERALS. iSg

(var. Aftinoliie), (CaO, MgO, FeO,) SiO', and (var. Hornblende), (MgO, CaO, FeO) (SiO=, Al'O'f) Their H 5.3 ; fusibility, 3—4. Tre- molite fuses to a white or light -colored glass, hornblende to a black or gray glass; the first is colorless or white, or of light-green, yellow, or gray color; hornblende and actinolite are green or black. Some varieties of Asbestos and Ami- anthus belong here. Nephrite is in part a tough, compact, fine-grained tremolite, having a tinge of green or blue, a splintery fracture, and some- what greasy feel. H 6 — 6.5.

Titanite, (CaO + TiO)SiO Fusibility, 3. H g — 5.5. Monoclinic. Gives the titanium reaction. § 111. Imperfectly soluble in hydrochloric acid.

Guarinite, of similar composition, but tetragonal.

Kdlhauite, containing 28 per cent, of TiO. Fuses with intumescence to a black shining glass. Yields with boras an iron-colored glass, which in the inner flame becomes blood-red. Reaction manganese with soda. Decomposed by hydro chloric acid.

Orthoclase, (KaKO) -f- 3SiO' + 6SiO' Albite with potassa replaced by soda. Hardness, 6. Fuse without intumescence ; fusibility orthoclase, 5 ; of albite, 4 ; the latter colors the flame yellow. Not soluble in acids. With solu- tion of cobalt become blue on the edges, § 44.

Oligoclase, (JCNaO, CaO)' -f iAl'0')'3SiO' SiO', is more fusible than albite. It sometimes resembles laboradorite, but, unlike it, is not ma- terially acted upon by acids.

Hyalophane is very similar to these minerals, but

o.led by

l86 DETERMINATION OF MINERALS.

CLASS II. — Fusibility 1—5 ; not, or only partially, volatile,

Division 6 — {continued).

if fused with potassa, treated ivith hydrochloric acid and water, the solution gives a precipitate of baryta with sulphuric acid.

Zaisiie, (i(3CaO) + f APO)'3SiO', and Epidote, (i(3CaO)+ KATO', FeW))''3SiO Hardness, 6.5. Fusibility, 3 — 3.5; fuse with intumescence — zoisite to a white or yellowish skg, epidote to a black or dark-brown slag. Color of zoisite, gray, yellowish-gray, grayish-white ; of epidote, green.

Garnet (var. Grossularite), (iCsCaO) -f Al'O')' 3SiO= ; (var. Fyrope), (CaO, MgO, FeO, MnO/ -f- AFO')* sSiO', and Vesuvianite, (|(CaO, MgO, FeO)' -1- |A]'0')'3SiO*. Hardness, 6,5— 7.5. Fusibility of lime garnet and vesuvianite, 3 ; of pyrope, 4.5. Vesuvianite pcBsessos cleav- age, the others not. Pyrope gives, with the fluxes, the chromium reactions, is not acted upon by acids, and is of a blood-red color. The others, green, yellowish-brown, hyacinth-red, and white.

Edelforsite (var. of WoUastonite'). H 6 — 7. Fusibility, 4 ; somewhat intumescent. Not acted upon by acids. Heated, gives a greenish-yellow phosphorescence. Sphenoclase, similar in its be- havior, but fuses quietly and more easily, and phos- phoresces with a faint yellowish light. (See also Emerald, Eudase, IoUte,Biotite,axiA Muscovite.')

Obsidian, Pitchstone, Pearhtone, and Pumice, SiO', A1'0°, NaO, KO, HO, are amorphous. Fusi- bility, 3.5 — 4; fuse with intumescence to porce-

o.led by

Determination Of Minerals. 187

Iain-like masses, or white vesicular glasses- Lus- tre of obsidian glassy, of pitchstone greasy, of pearlstone peaxly; pumice is characterized by its porosity.

CLASS in. — Mnsihle, or fusibility above 5.

Division i. After ignition, moistened with solution of co- balt and again ignited, assume a bright-blue color. (Some minerals should be first calcined and pulverized.)

With the hard, anhydrous minerals of this division, the color is best seen by reducing the substance to a fine powder and moistening this with the solution of cobalt. The color appears only after cooling, and by daylight. By calcination Alun- ite loses 13 per cent, water, Aluminiie 47, and a similar mineral, Felsobanyite, 37.

Pissophaniie, (APO', Fe'O'j'aSO' -f 30HO, black- ens in the flame, to which it gives a greenish tinge. Aluminite is white and opaque, while the latter is greenish and transparent.

(See, also, Alunogen and Tschermigtte, which are soluble in water, while the foregoing are not.)

Similar minerals: Trolleife contains 6 per cent, water; Spharite, 23; Tavistockile, iz.

Gibbsite, Al'O', 3HO ; Diaspore, Al'O', HO ; Sey~ bertiie, (APO', CaO, MgO, etc.), and Pholerite, 2AP0S 3SiO' -(- 4HO. Gibbsite is easily solu- ble in hydrate of potassa, and loses by ignition 34.5 per cent, water. The others are insoluble in potassa. Distinct cleavage in one direction. Seybertite loses per cent, water by ignition. Color, wax-yellow. Diaspore and pholerite lose ig per cent., and may be distinguished from the

o.led by

l88 DBTM.RMINATION OF MINERALS.

CLASS m. — InfusiWe, or fusibility ahove 5.

Division, I — {continued').

other minerals by their hardness. Diaspore, 6 ; pholerite, i. The last often occurs in scales with a mother-of-pearl lustre. Section I. Giving much water in a matrass.

Alunite, KO.SO'XAlOSO')' + 6HO ; Alumtnite, APO', SO' -f 9HO. Give a sulphur reaction, % 107. Aluminite is readily soluble in hydro- chloric acid ; alunite not visibly affected.

(See, also, Ammonia Alum, and Potash Alum.)

Plumbo-gummtte, see § 176.

Calamine, see § 214.

Wavellite, zklO, zPO'+iaHO; Evanstle, MKi*, 3HO--2Al=OPO*-|-I5HO; feganite, zAXQf, P0= + 6HO ; Pischerite, aAFO', PO + 8H0 ; Berlinite, APO', PO -f HO ; Richmondite, APO', PO" -I- HO. Soluble to a great extent in hydrate of potassa. Give the reactions of phos- phoric acid, §§ 94 and 95. The former two occur usually in globular concretions of radiated structure, the latter two minutely crystalline. Peganite loses on ignition 24 per cent, of water; wavellite, 27; fischerite, 29; richmondite, 35; evatisite, 40.

Allophane, ArO', SiOH 6H0 ; Halloysite, (KHO)' + JAPO'')' SiO' + 3HO; Samoite, 2APO', 3 SiO' + loHO i Collyrite, 2AP0>, SiC + 9HO. Decomposed by hydrochloric acid with separa- tion of gelatinous silica. Hardness of aUophano, 3 ; gelatinizes completely ; often colors the flame green, showing the presence of copper, and loses

o.led by

Determination Of Minerals. 189

by ignition 43 per cent, of water. Amorphotis. The hardness of samoite is 4, structure lami- nated, and loses by ignition 30 per cent. The hardness of the others is i — 2. Halloysite loses on ignition 16 per cent, of water; colly- rite, 33.5. CimoHte, aAl'O', pSiO' + 3HO ; Kaolinite, (HO)' + f Al'0')''3SJO' are very soft and earthy, and but little affected by acids ; lose on ignition from 12 to 16 per cent, of water. Nearly related to these minerals are the various varieties of com- mon clay, some varieties of lithomarge (with 14 per cent, of water), and bole with 24 — 26 per cent, of water; the clays become plastic with water, the latter two not. Compare also La%uliie, Svanbergite, Pyrophyllite, Agalmatolite, which yield water in matrass, but only a very little. Compare also Ripidolite. Section 2. Giving Httle or no water in a matrass. Alumian, Al'O', SO'. Before the blow-pipe on

coal, sulphur separates. Lamliie, P0>, APO' + MgO, HO. Gives the re- action of phosphoric acid, § 74. Heated, loses its blue color and becomes white. Not affected by acids. Svanbergite, P0 SOS Al'O', CaO, etc. On coal, sulphur separates; color, yellow, yellowish- brown. Wilhmite, 2ZnO, SiO'. With solution of cobalt (I 44) becomes blue, and green in spots. Gela- tinizes with hydrochloric acid. See § 215. Myelin, Al'O", SiO'; Agalmatolite, SiO', APO=, KO, HO; Pyrophyllite, (iClHO) + |AFO')

o.led by

igo DETERMINATION OF MINERALS.

CLASS in. — Infusible, or fusibility above 5. Division i — {continued').

sSiO'+JHO Are \en srift. Hardness, 1—2. Pyroph) llite is foliated like talc ; before the Blp, swells up and spreads out into fan-like shapes, increasing to about 20 times its former bulk. The others do not change before the Blp. Mye- lin is partially decomposed by hydrochloric acid ; agalmatohte not affected

Muscovite, 3a KO;' (,AlWj)' sSiO" + 2((K:0)> (AiO'))3SiO'. Cleavage eminent in one direc- tion ; folia elastic. Does not swell perceptibly before the Blp. ; fusible in very thin laminae. Not affected by acids. Hardness, z.5.

Disterrite (variety of Seybertite). Cleavable in one direction. Hardness, 4 — 5. Decomposed by concentrated sulphuric acid.

Andalusite, Al'O', SIO' ; Cyanite, Al'O", SiO', are but little affected by acids. Cyanite occurs generally in bladed crystallizations; hardness, 6 — 7. Hardness of andalusite, 7.5; but variety chiastolite varies in hardness from 3 to 7.5.

Sillimanite, WSrthite, Monrolite (vars. oiFibroliie), are closely related.

Topaz, Al'O, SiO=; RubelUte [Tourmaline], SiO=, BO', APO', MnO, I,iO, KO. Not affected by acids. Not completely soluble in S. Ph., the glass becomes opalescent on cooling. Topaz on being ignited remains transparent and does not swell; tourmaline becomes white and swells. Topaz is cleavable in one direction ; hardness, g. Tourmaline is not cleavable; hardness, 6,5.

o.led by

Determination Of Minerals. 19I

Corundum, [Sapphire"], Al'O'; Chrysoberyl, BeO, Al'O'. Not affected by acids. When pulverized, slowly but completely soluble in S. Ph. ; the glass does not opalesce on cooling. Hardness of chrysoberyl, 8.5 ; of corundum, 9. Color of the former usually green; of the latter, blue, red, yellow, brown. Compare Spinel.

(Some varieties of Leucite assume a blue color with solution of cobalt, but its hardness is not over 6. Cassiterite, also, in fine powder, takes a blue color, also green. Gives with cyanide of potas- sium globules of tin. Quarts also takes a pale blue color with a reddish tinge.) Division z. Moistened with solution of cobalt and ignited, assume a green color.

It is sufficient to heat to redness. The minerals of this division give a coating of oxide of zinc on charcoal, § 25.

Smithsonite, see § 213.

Hydrozincite [Zinc Bloom], ZnO,CO' + z(ZnO, HO). Dissolves readily in hydrochloric acid with effervescence ; the solution gives with am- monia a white precipitate, soluble in an excess of the reagent. Yields water in a matrass.

Wilkmiie, see § 215 ; Calamine, see § 214- Gelat- inize with hydrochloric acid. Calamine yields water, willemite not. With solution of cobalt, assume a green color only In spots.

(See Sphalerite and Goslarite, also Cassiterite.') Division 3, After ignition have an alkaline reaction, and change to blue the color of a moistened red lit- mus paper.

Brucite, MgO, HO ; Hydrodolomite, (CaO, MgO)

o.led by

192 De Termina Tjon Of Minerals.

CLASS m— Infusible, or fusibility above 5. Division -((ontinued).

C0= + fHO ; Hydromagnesite, MgO,HO + 3 (MgO.CO + HO). Yield much water in a mat- rass, unlike the other minerals of this division. Brucite dissolves in hydrochloric acid without effervescence, hydromagnesite with effervescence. The concentrated hydrochloric acid solution of the hydromagnesite is not precipitated by sulphu- ric acid, while the latter yields a heavy precipitate, Predazzite, 2CaO,CO' + MgO, HO, and Fenca- tite, CaO,CO'+ MgO, HO, are similar in behavior to the hydrodolomite. Pyrochroite, MnO,HO, is similar in reactions to brucite, but boiled with concentrated phosphoric acid, gives, on addition of nitric acid, a violet-red solution. Lancasterite, is a mixture of brucite and hydromagnesite. Nemaiite is a fibrous variety of brucite, of silky lustre.

Calcite, CaO. CO'; Aragonite, CaO, CO'. Dis- solve readily and with effervescence in dilute cold hydrochloric acid ; the concentrated (but not the dilute) solution gives a precipitate with sulphuric acid. Aragonite falls to powder be- fore the Blp., calcite not. (See Strontianite .')

Dolomite, MgO, CO' -j- CaO. CO"; Magnesiie, MgO. CO'. Do not, or but slightly, effervesce with cold dilute hydrochloric acid, but dissolve readily on application of heat. The concen- trated solution of the former gives a precipitate with sulphuric acid, that of the latter not.

A similar behavior shows the Breunnerite, (MgO.

o.led by

Determination Of Minerals. I93

FeO. MnO), CO' (ferriferous magnesite,) which on ignition becomes black and slightly magnetic ; and some varieties of Siderite, see § 163, and

Strontianite, SrO.CO''; Barytocalciie, BaO.CO" + CaO.CO'. Dissolve with effervescence in dilute hydrochloric acid ; the solution, even if largely diluted with water, gives a precipitate with sul- phuric acid. Strontianite colors the flame red, § 34; barytocalcite, yellowish-green, § 35.

(See also Yttrocerite.') Division 4. Completely soluble, or nearly so, in hydro- chloric or nitric acid, without gelatinizing or leaving a perceptible residue of silica.

Cervantite, SbO' + SbOS before the Blp., on coal, infusible, but with soda easily reduced to metal- lic antimony. Color, yellowish.

Stibiconite, SbO and Volgerite, SbO" + 5HO, are similar. They yield water in the matrass 5 per cent., and 15 per cent.

Siderife, see § 163; Breunnerite, see preceding division; Diallogite, see § 185; Zaratite, see § 195. Dissolve in heated hydrochloric acid with effervescence.

Mesitite, aMgO. CO -)- FeO. CO'. Blackens and becomes magnetic before the Blp. Slightly acted upon in the cold by acids ; but, if pow- dered, dissolves readily with effervescence in hot hydrochloric acid. Color, yellowish- white to brown. Streak, nearly white.

Ankerite, CaO. CO + (MgO, FeO, MnO)CO', is similar to the last. If dissolved in aqua regia, the iron precipitated by ammonia, a heavy pre-

o.led by

194 Determina Tion Of Minerals.

CLASS m. — Infusible, or fusibility above 5. Division i,{continued.

cipitate will be formed on addition of oxalate of ammonia.

Hydrotalcite, 6MgO.HO + AFO', 3HO + 6HO. Yields water in matrass. Does not become mag- netic in the reduction flame. In powder effervesces with hydrochloric acid and dissolves completely. If the solution is neutralized with carbonate of soda and filtered, oxalate of ammonia gives no precipitate in the filtrate, but phosphate of soda and ammonia do,

ParisiU, (CeO, LaO, DiO)CO' + i(Ca, Ce) F, is slowly soluble in hydrochloric acid with effer- vescence. The solution, not too acid, gives a white precipitate with oxalic acid which becomes brick-red by ignition.

Litrwnite see § 155 ; Gothite, Fe'O', HO. Become black and magnetic in the reduction flame. Dis- solve in hydrochloric acid without effervescence. Go thite occurs crystallized, and cleaves distinctly in one direction. Color, hyacinth-red, also brown and blackish-brown. Loses 10 per cent, on ignition. Limonite loses 14.5 per cent. Streak of both, ochre-yellow.

Turgite, aFe'O', HO, has a brownish-red powder, and loses by ignition 5.7 per cent, of water.

(See also Hematite, which in some varieties is without metallic lustre ; readily distinguished by red streak.)

Blende, see § 212 (var. Mamiatite, FeS sZnS); Greenockite, CdS. Dissolve in hydrochloric

o.led by

Determination Of Minerals. I95

acid with evolution of sulphuretted hydrogen. Give the sulphur reaction, § 107. Greenockite gives on charcoal a coating of oxide of cadmium, § 24, the others of oxide of zinc, g 25. Marma- tite gives, after calcination with the fluxes, the reactions of iron.

Wad, see § 184; Zincite, see § 211.

Asiolite (var. of Wad'), see § 132. Some varieties are fusible.

Uraninite, UO, U'O'; Zippeite, (U'O'aCuO/ 2SO' + 8H0. Give with the fluxes the reac- tions of sesquioxide of uranium [Table II]. Give with nitric acid a yellow solution in which ammonia produces a sulphur-yellow precipitate. Uraninite is black; zippeite, yellow. Sp. gr. of uraninite, 6.5.

Turquois, (A1'0*)T0 + 5HO. Color, sky-blue and green. Gives the copper reaction, g 74. Yields much water in a matrass, Sp. gr., 3.6 —

Apatite, (3CaO. P0=) + Ca (CI, F). Gives the phosphoric acid reaction, § 94. Fusibility, 5. Soluble in nitric acid. If the solution is not too acid, a precipitate of phosphate of lead is formed with the acetate, and of oxalate of lime with oxalate of ammonia. Sp. gr., 3.2.

Monazite, PO, CeO, LaO, ThO, DiO. Infusible. Gives the phosphoric acid reaction, § 94. Solu- ble in hydrochloric acid. Minute tabular crys- tals of reddish-brown color. Sp. gr., 4.95.2.

Childrenite, 2(FeO, MnO)*PO'+(Al=0')',P<y+i5 HO. Gives the phosphoric acid reaction, § 94. With the fluxes gives the reaction of iron and

o.led by

196 Determination Of Minerals.

CUS m. — Infusible, or Visibility above 5. Division 4 — {continued).

manganese. In hydrochloric acid soluble with difficulty. Yields much water. Sp. gr., 3.3.

Polycrase, TiO', CbO', Zf'O', Fe'O', Ce'0=, UO, etc. Decrepitates, but infusible. Color, black. On fusing the pulverized mineral with hydrate of potassa, dissolving the fused mass in water, neutralizing the filtrate with H. CI., a precipi- tate is formed, which, boiled with an excess of concentrated hydrochloric acid and tin foil, gives a cloudy blue solution, which filters clear and blue after the addition of a little water. This solution colors turmeric paper orange-yellow. Sp- gr., 5-

Fluocerite, CeF + Ce'P. Gives the reactions of fluorine, § 75, and of sesquioxide of cerium. Table II. Yitrocerite, CaF, CeF, YF., behaves similarly. Division 5. With hydrochloric acid gelatinize, or de- compose with separation of silica without gela- tinizing. Section 1. Giving water in a matrass.

Dioptase, CuO, SiO= -f HO; ChrysocoUa, see § 149. Behave alike before the Blp; the former gelatinizes with acids, the latter not.

Xonaltite, CaO, SiO' -f JHO. Massive ; very hard ; white to gray ; yields water ; infusible (?) ; decomposed by hydrochloric acid, in which solution of oxalate of ammonia gives a heavy precipitate, but ammonia none.

Thorite, ThO, S;0= + iHO; Cerite (CeO, LaO,

o.led by

Determination Of Minesals. I97

DiOy SiO' + HO. Gelatinize with hydrochloric acid. The solution of cerite, not too acid, gives with oxalate of ammonia a white precipitate, which becomes brick-red if ignited on platinum. Color of thorite is black ; streak, dark-brown ; hardness, 4.5 — 5 ; of cerite, brown to red, pass- ing into gray; streak, white; hardness, 5.5. Their sp. gr. is 4-7— S-

Chloropal, (gFeO, Fe'0')3SiO' 4HO ; Wokkon- skoite, MgO, A1=0', Cr'OS Fe'0=, SiO', HO, and Amorphous, withresinous lustre. Wolchonskoite is dark sea-green, and gives with borax an em- erald-green bead, which continues when cold. The others are yellowish -green. Chloropal gives a green bead, which fades on cooling, and gen- thite a violet bead in 0. FL, becoming gray in R. Fl. If the mineral is powdered and moist- ened with potassa, the chloropal becomes black without boiling ; genthite turns brown after boil- ing until concentrated, and wolchonskoite is not changed. Genthite gives off water in the closed tube and blackens.

Gillingite, [(CaO, MgO, FeO)'Fe'0']' sSiO' 4- 6 HO; Xylotik, Fe'O', SiO' + sMgO, 2SiO' + 5HO. Become magnetic by ignition. Readily decomposed by hydrochloric acid. Gillingite is black; amorphous. Xylotile is light or dark-, brown, of fibrous, woody structure.

Sepio/ite, (|MgO |H0) SiC -f- HO. Gelatin- izes with hydrochloric acid ; very light ; sp. gr., 1. 5 ; absorbs water with great avidity ; gives the magnesia reaction with solution of cobalt, § 44.

o.led by

198 Determination Of Minerals.

CLS m. — Infusible, or fusibility above 5. Division 5 — {conlinued).

Before the Blp., turns white and shrinks. Forms a jelly-like mass with hydrochloric acid.

Bastile QT SchilUr'Spar, 3([MgO. FeO], SiO') + z(MgO, 2HO); Chrysotiie, sMgO, 2810' + MgO, 3HO. Possess a metallic pearly lustre; the former is massive, cleavable ; the latter fibrous. By ignition schiller-spar becomes brown ; chrysotiie, white. Both are decomposed by hydrochloric acid, or more readily by sul- phuric acid, without gelatinizing. Metaxiie is greenish- white, similar to chrysotiie.

Ceroliie, (HO MgO)SiO' |HO. Amor- phous. H 2—2.5. 2.3. Color, green- ish, yellowish, reddish. Before the Blp., black- ens but does not fuse. Ignited mth solution of cobalt, a pale flesh-red color.

Serpentine, (|MgO |HO)=SiO'-|-HO. Decom- posed by concentrated hydrochloric acid without gelatinizing. Ustjally massive and compact ; hardness, 3 — 4; loss by ignition, 12 to 13 per cent. Of similar composition, and showing a similar behavior, are the following minerals, which, however, possess crystalline structure and cleavage : Ficrophyll — Fibrous ; greenish-gray ; hardness, 2.5; loss by ignition, per cent. Picrosmine — Greenish- white, dark-green, gray ; hardness, 2.7; loss by ignition, 9 per cent. Marmt>lite—GTetm%\\ and bluish-white ; hard- ness, 2.53; loss by ignition, 15.7 per cent. .ieOTWf?-£V— Hardness, 1.5 — 2] loss by igni- tion, 13 per cent.

o.led by

Determination Of Minerals. I99

(See also Chhrite and Ripidoliie, which are with difficulty decomposed by concentrated hydro- chloric acid.)

rtjtfye, 3(MgO.FeO),2SiO'+MgO,HO; Mon- radits, MgO, FeO, SiO'+iHO; Neolite, MgO, SiO' + HO[+ (AW, 3HO)]. Decomposa- ble by concentrated hydrochloric acid without gelatinizing. Loss by ignition, 4 to 6 per cent. Antigorite occurs in foliated maes ; hardness, 3.5. Monradite, hardness, 6. Neolite in silky fibres or massive; hardness, i.

(See, also, some varieties of Seybertite. Hardness, 4 — 5. Lustre, pearly submetallic. Color, red- dish-brown, copper-red.) Section z. Giving only traces or no water in a mat- rass.

GadolmUe, SiO'(YO, FeO, CeO, BeO)' ; Gehlm- iie, (CMgO, FeO, CaO)' + \(jeO\ Al'O'))'' SiO'. Gelatinize with hydrochloric acid. Gado- linite swells before the Blp. into cauliflower-like masses, and sometimes exhibits a vivid glow; thin splinters fusible on the edges ; color, black to blackish-green; hardness, 6.5 — 7. G=4 — 4.3. Gehlenite is also fusible in very thin splin- ters ; color, gray to grayish-white j hardness, 5.5-6- G=3- Chrysolite, (MgO, FeO)= SiO'. 7. Ckon- drodite, SMgO, sSiO", with part of the oxygen replaced by fluorine. H 6,5. Gelatinize with hydrochloric acid. Color of the former, green ; of the latter mostly white, yellow, or brown. Chondrodite gives the fluorine reaction, § 76, MontkeUite is isomorphous with chrysolite.

o.led by

200 Determination Of Minerals.

CLASS m— Infusible, or ftisibility above 5.

Division —{continued).

H=S — 5.5. Color, yellowish, greenish -gray, and white.

Forsterite, aMgO, SiO'. Cleavage distinct in one direction. Color, white, grayish, yellow, wax- yellow. Before the Blp., unaltered and infusi- ble. Decomposed by H. CI. with separation of gelatinous silica. Var. Boltonite gives traces of moisture in reiatrass and becomes colorless. (See also SeybertiU.')

Leucite, KO, SiO' + APC, 33iO'. Decomposed by hydrochloric acid, the silica separating as a fine powder; some varieties become blue with solution of cobalt ; occurs usually in trapezohe- drons. Color, grayish or white. 11=5.5. G

Division 6. Not belonging to either of the preceding divisions. The remaining minerals, which cannot be classed under any of the preceding divisions, may be divided according to their hardness in two sec- Section 1. Hardness below 7.

Biotite [Hexagonal Mica], (A1=0". Fe'O')', SiO + CMgO, K.0)', 3SiO'; M-uscovile [Oblique Mica], 3(3RO, RO')' 3SiO' + KzO, RO')3 SiO', [RO KO, NaO, MgO, R'O' Fe'OS AFC] ; Tak, (HO -!- MgO)SiO''. Give little or no water in a matrass. Talc loses at most 5 per cent. Cleavage eminent in one direction. Hardness of biotite, 3.5 — 3; of muscovite, 2 — 2.5;

o.led by

Determination Of Minerals. 201

of talc, 1 — 1.5. Biotite is decomposed by concen- trated sulphuric acid, tlie others not. The laminae of biotite and muscovite are elastic ; of talc not, Soapstone or Steatite is a massive, usually com- pact, variety of talc ; very greasy to the feel, or like soap, (See also Fyrophyllite.') Margarodite and Phlogopite are decomposed by sulphuric acid. Margarite, with pearly lustre, and (Ellacheriie, with 5 J per cent, baryta, are nearly related to the

Ripidoliie, sMgO, Al'O', 3SiO', 4HO. Lose by ignition 12 per cent, of water. Cleavage emi- nent in one direction, laminje not elastic (both often massive -granular). Hardness of prochlo- rite, 2; of ripidolite, 2 — 2.5. Decomposed by concentrated hydrochloric acid, with continued boiling, more readily by sulphuric acid. Ripido- lite fuses with difficulty (s-S) to a grayish-black glass; prochlorite becomes black and slightly magnetic. Ripidolite gives, with borax, a clear glass, colored by iron and sometimes chromium. Ripidolite is monoclinic ; prochlorite, hexagonal.

Lewchtenbergiie, H z 5 Colorless, white, yel- lowish white Before the Elp exfoliates and fuses with difficulty on the thin edges, becoming white and opaque P' H 2 — 25; 3 often on edges Color, green, red, and white. With flu\es, all varieties gne the reaction for iron, and mmy for chromium Completely decomposed sulphuric acid Ckloritoid is not perceptibly acted upon hydrochloric acid, but completely decomposed by sulphuric acid. H 5 — 6. Loss by ignition, 7J per cent.

o.led by

202 Determination Of Minerals.

CLASS m, — Infusible, or fttsibility above 5. Division d— {continued).

CeroUte [compare Div. 5, Sect. i]. Amorphous. Vellowish-white. H 2 — 3. Loss by ignition, 30 i>er cent. Mostly decomposed by hydro- chloric acid,

.5aaar/>, {ATO',FeW)2H0. Amorphous. Often oolitic, grayish, reddish-brown, and red. H 3. G'=3,s. Loss by ignition, 20 per cent. Only shghtly attacked by hydrochloric acid, but completely dissolved by concentrated phosphoric acid. (Compare ArgiUite.')

Wolchonskoite [see Div. 5]. Amorphous. Color, dark-green. Boiled with phosphoric acid, it gives an emerald-green solution, which, if dilated with water, retains its color, but gelatinous silica separates out. Chrondte also gives the chromium reaction, but its color is black, and streak yel- lowish-brown.

Warwickite, (MgO, FeO, TiO=, BO) Its powder is decomposed by sulphuric acid; evaporated to dryness and moistened with alcohol, it gives the green flame. If this mass is boiled with hydrochloric acid and tin foil, and concentrated, the solution is violet, or, diluted with water, rose-red.

Enstatite, MgO, SiO" ; Anthophyllite, (FeO -f MgO)SiO'. Cleavage of enstatite very perfect in one direction ; anthophyllite cleaves in two directions, under 124° 30'. The former is of clove-brown or pinchbeck-brown color, with a pearly-metallic lustre ; the lustre of anthophyl-

o.led by

Detbrmtnation Op Minerals. 203

lite is much less perfect. Hardness, 5 — 5.5. Hypersthene, (MgO, FeO)SiO*, is closely re- lated, and cleaves at 86°. H 5.5.

Tungstite, WC. Boiled with phosphoric acid it gives a bluish solution, which, shaken while warm with iron filings and a little water, becomes dark -blue. Occurs in soft, earth', yellow masses.

Schedite, CaO, WC. Fusibility, 5 ; hardness, 4.5 — 5, The pulverized mineral, on being boiled with nitric acid, leaves a lemon-yellow residue of tungstic acid. Gives the reactions of tungstic acid [Table II].

Cassiierite, see § 209.

Octahedrite, Rutile (both tetragonal, with adaman- tine lustre), and Brookite (orthorhombic), TiO'. Give the reactions of titanic acid [Table II]. On fusing the pulverized minerals with hydrate of potassa, dissolving the fused mass in hydrochlo- ric acid and boiling the solution with metallic tin, it assumes a violet color, which turns to red on addition of water. Color of octahedrite, various shades of brown, passing into indigo- blue ; of rutile, mostly brownish-red or red, sometimes yellowish or black ; of brookite, hair- brown, yellowish, or reddish (variety Arkansite is iron-black). Hardness of octahedrite, 5.5 — 6 of rutile, 6 — 6.5 ; of brookite, 5.5 — 6.

Euxenite and Aeschynite, CeO, LaO, YO, FeO, TiO', TaO=, CbO Pyrochlore, (CaO, CeO)', CbO''.(?) Treated like the preceding with potassa, etc., the solution on reaching a certain degree of concentration assumes a fine blue color, on

o.led by

204 Determination Of Minerals.

CLASS m.— Infusible, or fusibility above 5.

Division 6 {continued).

addition of water, which changes in the air to olive-green and gradually disappears. Aeschy- nite swells before the BIp. and turns yellow or brownish. The color is black; the powder, light-brown. Euxenite unaltered before the Blp. Color, brownish-black. Powder, reddish -brown. They have a metallic, greasy lustre. Pyrochlore is distinguished by its octahedral form. Color, brownish-red, and powder, light-yellow.

Ofal, SiO. Amorphous. Before the Blp. yields water and becomes opaque ; fuses with carbonate of soda to a clear bead, with effervescence. Infusible. Boiled with hydrate of potassa, it dis- solves completely or to a great extent ; the solu- tion gives a gelatinous precipitate with chloride of ammonium. Hardness, 6 — 6.5. G=2 — 2.3.

Xenotime, 3YO, PO*. Color, various shades of brown or flesh-red. Hardness, 5. G 4-4- Gives the phosphoric acid reaction, § 94. Infusible. With salt of phosphorus dissolves with great difficulty to a colorless glass.

(See also Childreniie and Orthoclass.') Section 2. Hardness, 7, or above.

(See Cassit'erite, Rutile, and Ca/of the preceding section, whose hardness sometimes approaches 7.)

Quartz, SiO'. The various varieties of quartz, as Rock-crystal, Amethyst, Hornstone, Flint, Chal- cedony, etc., are infusible and unalterable before the Blp., and fuse with carbonate of soda to a transparent bead, with effervescence. Hardness, 7. G=2.6.

o.led by

Determination Of Minerals. 20S

Mite, 2(FeO, MgO)SiO' + aAPO', sSiO' ; Stau- rolite, ((3FeO)+|Aro')'3SiO". Do not fuse to a transparent glass with carbonate of soda. Fusibility of iolite, 5 — 5.5 ; color, blue, grayish. G=iz.6. Staurolite is infusible ; color, brown- ish-red, brown ; crystals often cruciform. G

eryl, ((3BeO) + A?0')3SiO'j Euclase, ((3 HO) + KsBeO) + |A1W) SiO' ; Phenaciie, 2 BeO, SiO'; Zircon, ZrO, SiO Hardness, 7.5, Beryl and euclase turn milk-white with strong heat and become rounded on the edges ; beryl crystallizes in hexagonal prisms, and possesses pretty distinct basal cleavage ; color usually pale- green or emerald -green. Euclase crystallizes in clinorhombic prisms, and possesses distinct cleav- age in two directions at right angles to each other ; color, pale mountain -green, passing into blue and white. Phenacite and zircon do not change before the blow-pipe, excepting that zir con becomes colorless; color, red, yellow, o colorless ; zircon, sometimes brown or gray phenacite is a little harder (8) than zircon. G of zircon, 4.4; of the others, 2.7 — 3.

Taz, A1'0=, SiO'. H 8. G=3-5' 0"lio- rhombic. Before the BIp. infusible, Some varieties take a wine-yellow or pink tinge when heated. Fused in an open tube with salt of phos- phorus gives the fluorine reaction. With solu- tion of cobalt the pulverized mineral gives a fine blue on heating. Very slightly attacked by sul- phuric acid. Ouvarovite [Lime- Chrome-Garnet], (i(3CaO) -f

o.led by

206 Determination Of Minerals.

CLASS III.— Infusible, or fusibility above 5. Division 6 — {continued').

Cr'O'y sSiO', Ct'O', SiO'. Emerald- green. Infusible, but by ignition becomes blackish- green, and on cooling again, emerald -green. Hardness, 7.5 — 8, G 3.5. Gives with fluxes the chromium reactions [Table II].

Spinel, MgO, APC; Pleonaste, (MgO. FeO), Al'O"; GiiAwiVf, ZnO.AlW. Hardness, 7.5 Occur almost exclusively in octahedral crystals. Spinel and pleonaste, when pulverized, are solu- ble in salt of phosphorus ; color of spinel, red, blue, brownish ; of pleonaste black. Gahnite is almost insoluble in salt of phosphorus and borax color, dark-green or black. Kreittonite is a black spinel containing zinc and iron, slightly magnetic before ignition ; so also Dysluite.

Diamond, C. Characterized by its hardness, which surpasses that of corundum. H 10. G=3-S-3-6-

o.led by

Oxidized Minerals. 20/

THE OXIDIZED MIHEEALS, AESANGED ACCORD- INQ TO THEIE FUSIBILITY AND BEHAVIOR WITH CARBONATE OE SODA.

[From Planner's BlsTa-pipe Analysis.)

a. Minerals fusible to a bead.

a. With soda yield a fluid bead :

Aconite,

ElaeoUte*

Oligoclase,

Allanite*

Eudialyte,

Pyrasmolite,

Axinite*

Garnet,

Sassolilo,*

Boracite*

Helvite,

Scapolite,*

Borax,*

Hydroboracite,*

Sodalite (Greenland),

Botiyolite,*

Ilvaite,

Spodumene,

Crocidolite,

Labradorite,

Talc, black,

Cronstedtile,

Lapis Lazuli,

The Zeolites*

b. With a little soda a bead, with more a slaggy n Amblygonite, Okenite, Rhodonite,*

Fluorite, Orthite,*

Sodalite,

Garnet, manganiferous, Pectolite.

Sordavalite,

Manganese, black sili- Pyrorthite,

Vesuvianite.*

eate (hydrous tephroile ?),

c. With soda only a slag :

Amphodelite, Iron, phosphates of

Saponiie,

Autunite, sesquioxide.

Scaroditc,

Brevicite, Pharmacolite,

Tourmaline, potash,

Fahlunile, Pharmacosiderite,

(black).

Hauynite, Polybalife,

Triphylito,

Heterosite, Pyrargillite,

Wolframite.

Pyrope,

d. Sink with soda into the charcoal :

o.led by

200 Oxidized Minerals.

e. Fuse with soda at first more or less perfectly to a clear mass, but are decomposed by a sufficient quantity of soda, and leave behind an infusible crust, while the soda salt sinks into the coal :

Cryolite,

Gypam, Polyhsditi

/. Yield with soda reguline metal : Minerals consisting of reducible metallic oxides and their reducible salts.

b. Minerals wMoh fuse only on the edges. , With soda yield a fluid bead ;

Albite, Anorthite, Emerald (beryl), Euclase,

Petalite,

Sodalite (Ves

b. With little soda a fluid bead ; more, a slaggy mass : Enstatite, Epidote,* Hypersthene, WoUastonite, Zoisite.*

c. Yield with soda only a slag :

Carpholite, Pimelite, Dichtoite (iolite) blue, Finite,

Mica,* from granite, Pyrochloie,

Scbeelite, Serpentini Tounnalii

(green)

d. With soda goes into the coal :

Barite.

e. Fuse or only swell up with soda, but are decomposed by a sufficient amount of soda, leaving an infusible crust, while the soda salt sinks into the coal :

Apatite (swells up).

Barite (cakiferous), fuses.

o.led by

Oxidized Minerals.

c. Iiifosible Mmerala.

a. Give

with soda a fluid bead :

Agalmatolice,

Hisingerite,

Quartz,

Dioptase,

Leueite,

Rutile.

Fire-cky,

Pyrophyllite,*

Sidoroschisolite, Wolchonskite.

b. With

little soda, a bead ; with

more, a slaggy inas!

Cerite,

Gadoiinite,*

Talc,

Chrysolite,

Phenaeite, Picrosomine,

c. Yield,

, with soda, only a slag :

Aeschynite*

Chrome Ochre,

Ouvarovite,

AUophane,

Chrysoberyl,

Polymignite,

AlumiiiiEe,

Cyanite,

Spinel,

Aluiiite,

Diaspore,

Staurolite,

Alunogen*

riuocerine.

Tantalite.

Andalusite,

Gahnite (a linc coat)

, Thorite,

Brucite,

Gehlenite,

Titanic Iron,

Calamine (ai

Inccoat), Gibbsite,

Topaz,

Cassiterile, w

ith much Iron, sesquioxide anc

1 Worthite,

soda melallio tin, its sulphates,

Xenotime,

Chloritoid,

Manganese, oxides.

Yttrocerite,

Chromite,

Oersledite,

Yttrotanlalite,

d. Fuse or only swell up with soda, but are decomposed by a sufficient amount, and the soda sinks into the coal, leaving an infusible crust ;

Alum (kalinite), Calcite, Magnesite,

Aragonile, Dolomite, Wavellite.*

Barytocalcite, Epsomite,

e. Sinks with the soda into the coal: Strontianite.*

.,t.db,

Chapter Vii.

Colored Flames, Flame Reactions, and Spectrum

Analysis.

Many substances, when brouglit into a colorless or non- luminous flame, color it in a remarkable manner. The colorations are, in many cases, characteristic of the ele- ments yielding them, and furnish excellent means of detecting the latter, even in the minutest quantities, with great ease and certainty. Thus soda-salts tinge the flame yellow ; potassa compounds violet ; lithia-salts carmine-red ; and on account of this peculiarity they may be distinguished from each other by the simplest experiments.

The Bunsen lamp, with chimney, previously described (Fig. 2), is especially adapted to such observations. The substance to be tested is brought by means of the platinum wire-loop (Fig. 3) into the zone of fusion of the gas-flame. The alkalies and alkaline earths are most remarkable in their coloring effects on the flame. If we compare together various salts of the same base, we find that they all, if volatile at the temperature of the flame, give the same color, but tlie color differs in intensity, being strongest with the most volatile salts, and vice versd. Thus, chloride of potassium gives a deeper tinge to the flame than carbonate of potassa, and carbonate a stronger than silicate of potassa. Sometimes a non-volatile com- pound is made to exhibit a characteristic tint by the addition of some flux or decomposing agent. Silicates which contain but a few per cent, of potassa, and of them- selves do not color the flame, give a coloration after

o.led by

Col Os Ed Flames. 2 1 1

heating witli some pure sulphate of lime, which decomposes them, producing silicate of lime and volatile sulphate of potassa.

In mixtures of several substances which may be indi- vidually detected without difficulty, when they exist separately, it usually happens that a mixed and indecisive coloration is produced, or one substance masks all the Others. Thus, in a mixture of soda and potassa-salts, only a soda flame — in one of baryta and strontia-saJts, only a baryta flame is evident to the unassisted eye. We have recently learned two methods of dissecting these mixed flames so as to recognize their component colors with surprising facility and distinctness.

The first method, introduced into chemistry by Cart- mell, and further developed by Bunsen and Merz, consists in observing the colored flames through colored media (stained -glass, indigo solution, etc.). These act by extin- guishing the color of one metal, and thus developing that of the other. A mixture of soda and potassa, which to the eye has a pure yellow flame, when seen through a deep- blue cobalt glass or a solution of indigo, exhibits the violet tint of potassa, without any traces of the yellow soda flame. Cartmell detected lithia in the presence of soda and pot- ash, by comparing the mixed color of the flames of those bases with that of the flame of pure potash, when both are viewed through an indigo solution, Bunsen has found that the discrimination of these bases in presence of each other is more easily effected by observing the succession of changes of color, which the mixed fljune produced by these substances experiences when the rays reach the eye alter passing through gradually thicker layers of an indigo solution.

The apparatus for these observations is simple, viz. :

o.led by

2 1 2 Col Ored Flames.

1. A hollow prism, made of plate glass, Fig, 9, whose principal section forms a triangle, with two sides of 150 millimetres and one of 35 millimetres long. The solution with which it is filled is prepared by dissolving 1 part of indigo in 8 parts of fuming oil of vitriol, adding 1500 to 2000 parts of water and filtering.

In the following experiments the prism was moved horizontally before the eye, so that the rays of the flame always passed through gradually thicker layers of the medium. The alkaline substances, brought singly into the melting-space, exhibited the following changes;

a. Chemically purs CaCl. produces a yellow flame, which, even with very thin layers of the indigo solution, passed through a tinge of violet into the original blue lamp

b. Chemically pure NaCl., the same.

c. Chemically pure KO.COj or KCl. appears of a sky- blue, then violet, and at last of an intense crimson-red, even when seen through the thickest layers of solution. Admixtures of soda or lime do not hinder the reaction,

d. Chemically pure LiO,CO, or LiCl. gives a carmine- red flame, which, with increasing thickness of the medium, becomes gradually feebler, and disappears before the thickest layers pass before the eye. Lime and soda are also without influence on this reaction,

2. A blue, a violet, a red and a green glass. The blue is colored by protoxide of cobalt ; the violet, by sesqui- oxide of manganese ; the red (partly colored and partly uncolored), by suboxide of copper; and the green, by sesquioxide of iron and oxide of copper. The stained glasses found in commerce and employed for ornamenting windows, generally possess the requisite shades of color.

MerK, who has made a complete investigation of this

o.led by

Colored Flames. 213

subject, employs with these glasses Buiisen's burner, and also a flame of pure hydrogen. The substances which he describes as giving characteristic colors to the flame of Bunsen's burner, in addition to those previously known, are nitric and chromic acids, while phosphoric and sul- phuric acids give a peculiar coloration to the dark core of the flame of hydrogen.

The flame of Bunsen's burner gives three sorts of color:

a. Border Colors. — These are of course peculiar only to the most volatile substances. To produce them, the loop of platinum wire is to be held outside of the flame about one or two millimetres from the lower portion of the

b. MantlB Colors. — Those, namely, which are seen when the substance is held in the bright blue-colored mantle which fornis the outer portion of the flame.

c. Flame Colors. — To produce these, the loop is to be held horizontally and in the hottest part of the mantle. The hydrogen flame yields another species of color, viz. , the

d. Core Colors. — These are produced only by sulphuric and phosphoric acids, which communicate respectively a blue and green tinge to the cold core of the hydrogen flame.

The following, according to Merz, is a list of the more commonly occurring substances which color the flame, with the color they impart ;

Blue

Flames

(

Consult

6.)

IntenBe blue, .

Chloride of copper.

Pale dear blue.

Light blue,

Aiseiiic.

Greenish blue, .

Antimony.

Blue mixed with gi-een

Bromide of copper.

[Slue: core color.

Sulphuric acid.

.,t.db,

Colored Flames.

Green Fla

Hes.

{Consult page

Bronze- green border color,

.17-)

Nitric and Nitrous acic

Ammonium compotinc

Greenish-blue border color,

Cyiinogen Hydrochloric acid.

Green mantle color, .

Boracic acid.

Gray yellow-green border color, Yellowish-green flame color, .

Phosphoric acid.

Dark green, Full green, Intense emerald .

Iron wire.

Copper,

Iodide of copper.

Emerald green, mixed willi blue,

Bromide of copper.

Pale green, . Intense whitish green, .

Phosphoric acid. Zinc.

Red Flam

(Consult pag

Reddish purple, Violet, Dark "brownish-red border color! and a rose-red mantle color, /

Es.

Stronliiim compounds. Calcium compounds.

Chromic acid.

Yellow Fla

Mes,

Yellow,

Feeble brownish- yellow.

2l8.)

Sodiim compounds. Water.

le, aiidCuO.

NOj a pure green flame color. By the combined observa- tion of both colors, Cu. may be distinguished from all other metals which give similar colors. The other flame- coloring metals, such as As., Sb., Sn., Pb., Hg., and Zn. exhibit, especially in the form of chlorides, more or less intense bluish or greenish mantle colors, which, however, cannot be advantageously used as reactions for the metals themselves.

o.led by

Colored Flames. Sij

Sulphuric acid produces a beautiful blue core color, being reduced to SO3. Tlie free acid gives the color when the platinum loop is held in the border of the flame, but a sulphate must be held in the middle of the flame. In the latter case, it is well to dip the test into strong HCl. or fluosilicic acid.

Green Flames. — Nitric and nitrous acids give a bronze- green border color, usually with an orange-colored border. The test is to be previously dried in the flame, and dipped into a solution of K0,2S0a, or into dilute HCL, according as we wish to test for nitric or nitrous acid. Ammoniac and cyanogen compound give the same bronze-green border, but more faintly. HCl. gives a very weak greenish-blue border color, which lasts for a very short time, and there- fore does not deserve attention. The acid is, however, decomposed, and the CI. may easily be recognized.

Boracic acid gives a beautiful green mantle color, which is so intense that the acid may be recognized in the presence of large quantities of phosphoric acid. Borates are to be decomposed with SOa. Phosplioric acid gives a gray yellow-green border color as well as a beautiful green core color. The dry test is to be dipped into SOj and held in the flame in the manner already pointed out, in order to show the border color. The green core color is less sensitive, but indispensable in recognizing phosphoric acid in the presence of large quantities of boracic acid, and is produced by alternately moistening the test with a solution of fluosilicic acid, and igniting it in the hydrogen flame, until the color distinctly appears.

Ba, may be recognized by the yellowish-green flame color, which appears blue-green through the green glass. If the green disappears, and a red flame color makes its appearance, the test is to be repeatedly moistened with

o.led by

2l6 FLAME REACTIONS.

HCl,, and immediately introduced while wet into the hottest part of the flame. When the blue-green color is no longer seen, proceed to examine for Ca.

Red Flames. — Ca. is present when the red flame color, on evaporating the last portion of HCL, appears siskin- green through the green glass. Sr. gives in this case a weak yellow. Sr. may be recognized by the purple or rose color which is seen through the blue glass, when the test, after moistening with HCl., is evaporated to dryness in the flame.

K. gives a gray-bke mantle color, and a rose-violet flame color. These colors appear reddish- violet through the blue glass, violet through a violet glass, and blue-green through a green glass. The test is to be moistened with SOj, and repeatedly exposed to the flame for a short time.

Chromic acid gives a dark brownish-red border color, and arose-red mantle color. The dry test is to be moistened with concentrated SO,, and held in the border. Chromic oxide gives no color, and xs to be first oxidized to chromic acid by moistening with a solution of hypochlorite of soda and drying.

Yellow Flames. — Na. gives an orange-yellow flame color, which in very large quantities appears blue, but in small quantities is invisible through the blue glass. Through the green glass the flame appears orange-yellow, even with the smallest quantities ; this glass is particularly adapted to the recognition of Na. in all its compounds. The test should be moistened with SOj, dried and held in the hottest point of the flame,

Bunsen'S Flame Reactions.

Almost all the reactions which can be performed by means of the blow-pipe may be accomplished with greater

o.led by

Flame Reactions. 21J

ease and precision in the flame of the non-luminous gas- lamp. This flame, moreover, possesses several peculiarities which render it available for reactions, by which the small- est traces of majiy substances occurring mixed together can be detected with certainty, when the blow-pipe and even still more delicate methods fail. Only the principal reactions that can be obtained in this way are here given.

BUDSen's Gas-Lamp. — This lamp, with non-luminous flame, is represented in Fig. 2, and must be made about three times as large as the drawing. It must be furnished with a cap for closing and opening the draught-holes, SO as to be able to regulate the supply of air for every dimension of the flame. The conical chimney d d d d, Fig. 20, must also be made of such a size that the flame burns perfectly steady. Fig. 20 represents the flame of its proper size. It is composed of the following three chief divisions :

A. The dark cone, a a a a, containing the cold unburnt gas mixed with about 62 per cent, of air.

E. The flame mantle, a c a b, formed of the burning coal-gas raised with air.

C. The luminous point, aba, not seen when the lamp is burning with the draught-holes open, but obtained of the size required for the reactions by closing these holes up to a certain point.

The following six points in the flame are used in the reactions :

1, The base of the flame lies at a; its temperature is comparatively very low, as here the burning gas is cooled the upward current of cold air, and much heat is ab- sorbed by the cold end of the metal tube. If mixtures of flame-coloring substances are held in this part of the flame, it is often possible to vaporize the most volatile constitu-

o.led by

2l8 FLAME REACTIONS.

Fig. 20.

Ho.led by

Flame Reactions. 219

ent, and thus in the first few moments to obtain tints which cannot be observed at higher temperatures, because they then become masked by colors produced by the vola- tilization of the remaining substances.

2. The zone of fusion lies at ,8, somewhat above the first third of the flame in height, and midway between the in- ner and outer limits of the mantle at the point where the liame is thickest. This is the point in the flame which possesses the highest temperature, and it is therefore used in testing substances as regards their melting-point, their volatility, emissive power, as well as for ail processes of fusion at high temperatures,

3. The lower oxidizing flame lies at y, in the outer mar- gin of the zone of fusion, and is especially suitable for the oxidation of substances dissolved in beads of fused salts.

4. The upper oxidizing flame at is formed by the high- est point ot the non lummous flame, and acts most power- fully when the draught holes of the lamp are wide open. This flame is suited for the oxidation of larger portions of substance, for roasting off volatile-oxidation products, and generally for all those cases of oxidation in which an ex- cessively high temperature is not needed.

5. The lower redncing flame lies at a, on the interior edge of the mantle next to the dark central zone. As the reducing gases at this point are mixed with unbumt atmo- spheric oxygen, many substances remain here unaltered which become deoxidized on exposure to the upper reduc- ing flame. This point of the flame gives, therefore, very valuable reactions which cannot be obtained ivith the blow-pipe. It is especially available for reductions on charcoal, and in beads of fused salts.

6. The upper reducing flame is formed by the luminous point ri, produced over the dark zone when the admission

o.led by

220 Flame Reactions.

of air is lessened by the gradual closing of the draught- holes of the lamp. If this luminous point is made too large, it will be found that a test-tube filled with cold water becomes covered with a film of lampblack : this never ought to occur. This flame contains no free oxy- gen, is rich in finely divided incandescent carbon, and hence it possesses far more powerful reducing powers than the lower reducing flame. It is especially available for reducing metals when it is desired to collect them in the form of films,

Method Of Examiitation In The Various Parts Of The Flame,

A. Beliavior of the Elements at High Temperatures.*

This is one of the most important reactions which can be employed for the detection and separation ot sub- stances. The possibility of producing, with the flame of the lamp alone, a temperature as high as, or higher than, that of the blow-pipe depends upon the fact that the radi- ating surface of the heated body be made as small as pos- sible. The arrangement for bringing the substances into the flame must therefore be on a very small scale. The platinum wire upon which the substance is heated must scarcely exceed the thickness of a horsehair, and one deci- metre in length of the wire must not weigh more than 0.034 grm. It is impossible to obtain the results hereafter detailed if a thicker wire tlian this is employed. Sub- stances which act upon platinum, or which will not adhere to the moistened surface of the metal, are held in the flame

*For further information with regard to the flame reactions, the student is referred to the translation of Bunsen's paper by Professor Roscoe in the " Pliilosophical Magazine " for 1S6;.

o.led by

Flame Reactions.

Upon 1 tlim thread of asbestos, of which a hundred may be obtuned Irom one splinter of the mineral. These threads Fit, 31 rig' 32.

irmst not exceed m thickness one-fourth of that of an ordi- nary luiifer match Decrepitating substantes are ground to the finest powder on the porcelain lamp-plate with the

o.led by

223 Flame Reactions.

elastic blade {a) of the knife (Fig. 21), and drawn up on to a moistened strip of one square centimetre of filter paper. If the paper is then burnt, being held with the platinum forceps, or, better, between two rings of fine platinum wire, the sample remains as a coherent crust, which now may without difficulty be heated in the flame.

If the substance requires to be healed in the flame for a long period, the holder (Fig. zz) is used. The arm {a) is fastened to the carrier (A), so fixed on the stand by a spring (as seen at B) that it can be moved both horizontally and vertically. The glass tube (Fig. 23) is held on this ann (a), and the fine platinum wire fused on to the tube thus held in the flame. The splinters of asbestos are stuck into the glass tube {b'), which slips into the holder, and may then be moved with the carrier (A). The carrier (B) car- ries a spring-clamp for holding test-tubes which have to be heated for a considerable time in a particular part of the flame. TTie little turn-table (C) contains nine upright supports to hold the wire tubes (Fig. 23) employed in the experiments. By means of these arrangements a particle of the substance under examination is brought into the flame, and its behavior in the coldest and hottest parts of the flame is ascertained, the substance being examined with a lens after each change of temperature. The follow- ing six different temperatures can be obtained in the flame, and these points may be judged of by observing the tints attained by the thin platinum wire :

1. Below a red heat.

2. Commencing red heat.

3. Red heat.

4. Commencing white heat, g. White heat.

6. Strong white heat.

o.led by

Flame Reactions. 223

It is scarcely necessary to remark that these differeDt temperatures must not be ascertained by the glow of the substances themselves, as the luminosity of different bodies depends not only upon the temperature, but also mainly upon their specific power of emission.

The following phenomena are observed when a sample of a substance is heated :

1. Emission of Light. — The emissive power of sub- stances is ascertained by placing them on the platinum wire in the hottest part of the flame. The sample is of weak emissive power when it is less luminous tlian the platinum wire; of a mean emissive power when both appear about equally luminous; and of strong emissive power when the intensity of the light which it emits is greater than that from the platinum. Most solid bodies emit a white light, others (as, for instance, erbia) colored light.

Some bodies, such as many osmium, carbon, and molyb- denum compounds, volatilize and separate out finely di- vided solid matter, which renders the flame luminous. Gases and vapors always exhibit a smaller power of emis- sion than fused substances, and these generally less than solid bodies. The form of the substance under examination must always be noted, as the emissive power depends upon the nature of the surface ; thus compact alumina, obtained by slowly heating the hydrate, possesses only a moderate emissive power, whereas the porous oxide prepared by quick ignition of the sulphate possesses a high power of

2. The meltillg point is determined by using the six different temperatures already mentioned. At every in- crease of temperature the bead is examined with the lens to see whether the volume is decreased or increased, whether bubbles are given o£f on melting, whether on.

o.led by

324 Flame Reactions.

cooling the bead is transparent, and what changes of color it undergoes during the action of the heat or on afterwards cooling.

3. The volatility is ascertained by allowing equally heavy beads of the substance, placed on a platinum wire, to evaporate in the zone of fusion, and observing the time, by means of a metronome, which the bead takes to volatilize. The point at which the whole of the substance is converted into vapor can be ascertained with great accuracy, often to a fraction of a second, by the sudden disappearance of the coloration of the flame. The plati- num wire upon which the substance is weighed Fig. 34. is protected from the moisture of the air by insertion in a tube (Fig, 24). If we know the weight of the tube and wire, the right weight of substance can easily be attached, either bv \oiatilizing a portion or by fusing some more substance on to the bead, and thus makmg it lighter or heavier. The experi- ments are best made with one centigramme of substance. The position in the flame where the highest constant temperature evists can be found by moving a fine plati- num wire, fixed on a stand and bent at its pomt at a right angle, slowly about the zone of fusion, and noting the point where it glows most intensely. The beads to be volatilized are then most carefully brought into the flame at the same distance from the point of this wire. Care must also be taken that the dimensions of the flame do not undergo change from alterations in the pressure of the gas while the experiments are going on. 4. Mame coloration, — Many substances which volatilize

o.led by

Flamr Reactions. 22$

in the flame may be detected by the peculiar kinds of light which their glowing gases emit. These colorations appear in the upper oxidizing flame when the substance causing them is placed in the upper reducing flame. Mixtures of various flame-coloring substances are tested in the lowest and coldest part of the flame ; and here it is often possible to obtain for a few moments the peculiar luminosity of the most volatile of the substances unaccom- panied by tliat of the less volatile constituents.

E. Oxidation and Reduction of SulDstaneea.

In order to recognize substiinces by the phenomena exhibited in their oxidation and reduction, and to obtain them in a fit state for further examination, the following methods are employed :

1. Kfidnetion in glass tubes is especially employed for the detection of Hg., or for the separation of S., Se., P., etc., when in combination with Na. or Mg, A stock of very thin glass tubes is prepared, each 2 to 4 mil- lims. in width and 3 cen- tims. in length; forty of these are easily made out of one ordinary-sized test-tube, by softening the glass before the blow-pipe, and then drawing it out until the requisite size of tube is obtained. This long tube is then cut up with a diamond into pieces 6 to 8 centims. long, and each of these again divided into two over the lamp, and the closed ends neatly rounded. The sample, having been finely pojydered with the knife-blade (Fig. 21, a) on the porcelain plate (Fig. 25).

o.led by

226 Flame Reactions.

is treated in a tube either by itself, or with a mixture of carbon and soda, or witli Na. or Mg. Apiece of magnesium wire, a few millims. in length, is for this purpose piished down into the powdered sample contained in the glass tube; the sodium is carefully freed from rock oil, and rolled out between the fingers to a small cylinder, which is then surrounded by the powdered substance. The best form of carbon is the soot from turpentine, which has been de- posited upon the outside of a basin filled with cold water. As soon as the small tube containing the perfectly dry sample has been heated to the point of fusion of the glass, when generally an ignition inside the tube is noticed, it is allowed to cool and then placed upon the porcelain plate covered by a piece of paper and crushed to powder with the knife, for the purpose of further examining the pro- ducts of reduction.

2. Reduction on Splinters of CliarcoaL — In this way the metal can be obtained in small globules, or as a porous mass, from quantities often leas than a milligramme of the sample.

A transparent crystal of sodic carbonate is brought near to the outside of the flame, and a common wooden lucifer match then rubbed over two-thirds of its length with the drops of fused salt. If the match is then turned upon its axis through the flame, the carbonized wood becomes sur rounded with a crust of solid sodic carbonate, which, on heating in the zone of fusion, melts, and is absorbed by the carbon. A splinter of charcoal is thus obtamed, which is prevented from burning by its glaze of soda A mixture of the substance is then made with the knite upon the hand with one drop of the melted soda-crystal, and a portion of this, of the size of a mustard-seed, placed upon the point of the splinter. As soon as this has been melted

o.led by

Flame Reactions. 22/

in the lower oxidizing flame, it is passed through a part of the dark interior zone to the hotter portion of the lower reducing flame. The point at which the reduction occurs is easily seen by the violent effervescence of the soda ; and this is after a time stopped by bringing the splinter into the dark zone. In order to isolate the reduced metal, the end of the splinter is broken off and rubbed up with a few drops of water in a small agate mortar, when the metallic particles are generally visible without removal of the car- bon. For further examination, the carbon and soda can be easily removed by several careful washings, and the par- ticles transferred to a small piece of curved glass cut out from an old fiask,* in which they are again washed by decantation, the last drops of water removed by suction with a piece of filter-paper, and the metallic particles dried at a moderate heat. A few tenths of a milligramme of the metal is generally sufficient to yield a solution with which all the characteristic precipitations can be accomplished, the reagents being contained in capillaxy glass threads, dropped into the solution by the milligramme, and the effect thus produced ascertained by examination with a lens. Iron, cobalt, and nickel, which do not fuse to glob- ules on the splinter, are withdrawn from the agate mortar by means of the point of the magnetized blade (Fig, 21,), washed with water, and dried high above the flame on the point of the knife. If the blade be then tightly drawn between the upper part of the thumb and the lower part of the first finger, and if the point of the blade be then approached to the metallic particles on the finger, they jump from the hand to the blade, forming a brush-like bundle, which can be conveniently examined by the lens, Watch-glasses crack much too readily to be used for such expert-

.,t.db,

228 Flame Reactions.

and by toucliing with a melted borax bead can be trans- ferred in suitable quantities. The portion of metal remain- ing on the knife b rubbed on to a small piece of filter- paper, a drop of acid added, and the paper warmed over the fiame so as to allow the metal to dissolve ; this solu- tion can then be further examined with various reagents.

3. Films upon Poreelaifl. — Those volatile elements which arc reduced by carbon and hydrogen can be depos- ited from their compounds as films on porcelain, either in the elementary state or as oxides. Such films can be extremely easily converted into iodides, sulphides, and other compounds, and thus may be made to serve as most valuable and characteristic tests. The films are composed in the centre of a thick layer, which on all sides gradually becomes thinner until the merest tinge is reached ; it is therefore necessary to distinguish between " thick" and " thin " parts of the films. Both exhibit in their varia- tion of thickness all the tints of color characteristic of the substance under different circumstances of division. One- tenth up to one milligramme is in many cases sufficient for these reactions. Many surpass Marsh's arsenic test in delicacy and certainty, and approach in this respect the spectrum-analytical methods.

The following films can be obtained :

(a) Metallic films are prepared by holding in one hand a particle of the substance on an asbestos thread in the upper reducing flame, which must not be too large, whilst with the other hand a glazed porcelain basin, i to z decime- tres in diameter, filled with cold water, is held close above the asbestos thread in the upper reducing flame. The metals separate out as dead-black or brilliantly-black films of varying thickness. Even Pb., Sn,, Cd., and Zn. yield in this way films of reduced metal, which by mere inspec-

o.led by

Flame Reactions. 229

tion cannot be distinguished from the soot separated out on the porcelain by a smoky flame. By means of a glass rod, these films can be touched with a drop of dilute HNO3, containing about 20 per cent, of real acid ; and the various degrees of solubility of the films serves as a dis- tinguishing characteristic.

(i) Oxide films are obtained by holding the porcelain basin filled with water in the upper oxidising flame, the rest of the operation being the same as in the produc- tion of the metallic films. If only a very small quantity of the sample can be employed, care must be taken to lessen the size of the flame, in order that the volatile products may not be spread over too large a surface of porcelain.

The film of oxide is examined as follows :

(b) The color of the thick and thin film is carefully observed.

The reducing action or otherwise of a drop of stan- nous chloride is noted.

(y) If no reduction occurs, NaHO. is added to the stannous chloride until the precipitated hydrate redJs- solves, and then it is to be observed whether a reduction

(i) A drop of perfectly neutral silver-nitrate is rubbed over the film with a glass rod, and a current of ammonia- cal air is blown over the surface from a small wash-bottle containing ammonia solution, and having the mouth-tube dipping under the liquid and the exit-tube cut off close below the cork. If a precipitate is formed, the color is observed, and the solubility or alteration, if any, noticed, which occurs when the current of alkaline air is continued, or when a drop of ammonia-liquor is added.

[li) Iodide films are simply obtained from the oxide-

o.led by

230 Flame Reactions.

films bj LrLithing on the latter upon the cold basin, which ih. then placed, upon the wide- mouthed, well-stoppered glass (Fig. z6), containing fuming hydriodic acid and phosphorous acid derived from the gradual deliquescence of phosphoric triiodide. When the mixture no longer fumes, owing to absorption of moisture, it i& easy to render it again fuming by iddmg a httle phosphoric anhydride. Other films, often containing both iodides of a metal, and therefore frequently less regular in color and appearance, may be easily obtained by smoking the oxide film with a flame of alcohol containing lodme in solution placed upon a bun- dle ot asbestos thieads and held under the basin. If any iodine be condensed on the basin with the HI., it can easily be removed by gentle warming and blowing. The examination of the film is conducted as follows: (a) The solubility of the film is examined simply by breathing upon it when the basin is cooled ; the color then either changes or entirely disappears, the film being dis- solved in the moisture of the breath. If the basin be gently waraied, or if it be blown upon for some distance, the film again becomes visible by the evaporation of the moisture in the current of air.

(/?) The ammonia compound of the iodide is formed by blowing ammoniacal air upon it, and noticing whether the color of the thick and thin films alters quickly, slowly, or not at all. The different colors reappear at once if the basin be held for a few moments over an open bottle con- taining fuming HCl.

(y) The iodide films generally give the same reactions

o.led by

Flame Reactions-.

as the oxide films with silver-nitrate and ; stannous chloride, and with caustic soda.

(b) The Sulphide film is most easily obtained from the iodide film by blowing upon it a current of air saturated with ammoniac sulphide, and removing the excess of sul- phide by gently warming the porcelain. It is advisable to breathe on the film from time to time whilst the current of sulphuretted air is being blown on the basin. The ex- periments to be made with this film are :

The solubility or otherwise in water is ascertained by breathing on it, or by addition of a drop of water. The sulphides often possess the same color as the iodide films ; they may, however, generally be distinguished by their insolubility on breathing.

(/3) The solubdity of the sulphide in ammoniac sulphide is ascertained by blowing or dropping.

{b') Films on Test-tubes. — Under certain circumstances it is advisable not to collect the film on porcelain, but upon the outside of a large test-tube (Fig. az, D) ; this method is especially used when it is needed to collect larger quantities of the reduction film for the purposes of fiirther examination. The fine asbestos thread with the sample of substance is held on the glass tube ifi) before the lamp so that it is placed at the height of the middle of the upper reducing flame, and the test-tube fixed so that the lowest point is just above the end of the asbestos thread. If the lamp be now pushed under the test-tube, the substance and the asbestos thread are in the reducing flame. By repeating this operation the film can be obtained of any wished-for thickness ; some pieces of marble are in this cse placed in the test-tube, to prevent the water from being thrown out of the tube by percussive boiling.

o.led by

Volatile Elements.

Table Ob Toiatile Eiemests Which Cau Be Eeiucei) As Films.

OXIDH riLU.

™KmE.'''

TwS.t'™

Te

Sr'i„S"

WhiK.

Black.

Eiack.

v-hiS! '

Se

Chsiry-rcd :

™..

Erick-red.

„.

„,.

Sb

; thin

whiK.

While.

Lilack: insoliEbk in

part brown.

While.

Wliite.

„

S'uS

Elick.

White.

Kg

Gray 1,01.-™-

Tl

Ww.S.

While.

Wiiiie.

Pb

Black; dlin

Yellow-ochre color.

Whilo.

\Vhiie.

Black; thin

b™'l''th"in

While.

™..

While; imhe 'biSMk""

Zi,

WhiK.

Sn

Katk ; tiiiE

Ylowish- whiK.

whiB.

WhiK.

While.

H.,t.db,

Volatile Elements.

TABLE OF VOLATILE ELEMENTS WHICH CAN BE REDUCED AS FILMS — Continued.

aT

b"

Browi,;

D .

SIISt'

D

g"

Elements nhnse rcducuri, films

™n breath "

o g

Dsa 15

tune"'™ bre Ih bg.

alee ?

Len.

Doe dia-

Blulsh- ihin pans p

Pm lo

be™ ""

ff

Carmine-coloied

Dsa p=i

'

D dis-

are""!"* di

ass

Ifimon-yelJow does noI d p-

Does

Orange-ydjo ing.

D.

M

1>.

D dis-

diiolved

acid.

Whit=,

H.,t.db,

234 Special Reactions.

C. The Reactions of the Elements.

The elements, which can easily be recognized by their flame reactions, are arranged in the following groups and sub-groups according to their behavior in the reducing and oxidizing flames :

A. Elements which are reflucible to metal and are deposited in films.

1. Films scarcely soluble in cold dilute nitric acid — Tellurium, selenium, antimony, arsenic.

2. Films slowly and difficultly soluble in cold dilute nitric acid — Bismuth, mercury, thallium,

3. Films instantly soluble in cold dilute nitric acid — Cadmium, zinc, indium.

E. Elements reducible to the metallic state, giving no film:

1. Not fusible to a metallic bead.

a. Magnetic — Iron, nickel, cobalt.

b. Non-magnetic — Palladium, platinum, rhodium,

2. Fusible to metallic beads — Copper, tin, silver, gold.

C. Elements most easily separated and recognized as compounds — Tungsten, titanium, tantalum and niobium, silicon, chromium, vanadium, manganese, uranium, sul- phur, phosphorus.

Special Reactions,

1. Tellurium Compouads. — -f/rai? coloration, in upper reducing flame, pale-blue, whilst the oxidizing flame above appears green.

Volatilitation unaccompanied by any odor.

Reduction film, black, with dark-brown coating, or

o.led by

Special Reactions. 235

brilliant ; heated with concentrated sulphuric acid, gives a carmine-red solution.

Oxide film, white, scarcely, or not at all, visible ; pro- tochloride of tin colors it black, by reason of separated tellurium ; nitrate of silver, after ammonia has been blown upon it, yellowish-white.

Iodide film ; dark-brown, with brown coating ; disappears momentarily when breathed upon, but not when slightly warmed ; reappears on exposure to HCl. ; blackened by SnCl.

Sulphide film, dark-brown to black ; does not disappear when breathed upon ; dissolves in NHjS. blown upon it, and reappears upon warming, or if blown upon with air.

With soda on charcoal splinter gives a telluride of sodium, which, when moistened upon a silver coin, pro- duces a black spot, and if the specimen contains much tel- lurium, with HCl., diffuses an odor of telluretted hydro- gen with the separation of black tellurium.

2. Selenium Compounds. —i/awi fo/fraC/i'j, pure azure- blue.

Volatilises, burning with the odor of selenium. Reduction film, brick-red to cherry-red ; at one time dull, at another brilliant ; gives, when heated with con- centrated SOj, a dirty-green solution.

Decide film, white ; brick-red from separated selenium when SnCl. is dropped upon it ; the old color darkened by NaO, HO; with AgO, NO4 the oxide film gives a white, scarcely visible coloration, which disappears when ammonia is blown upon it.

Iodide film, brown, contains some reduced selenium, and therefore cannot be made to disappear completely, either by breathing upon it or by blowing ammonia upon it.

o.led by

23 Special Reactions.

Sulphide film, yellow to orange-red, insoluble in water, soluble in NHS.

With soda en charcoal splinter gives selenide of sodium, which produces, with a drop of water, a black spot upon a silver coin, and moistened with HQ., if the quantity is not too snull, gives the odor of selenuretted hydrogen with separation of red selenium,

3. AntimOBy Compounda. — Flame coloration, by treat- ment in the upper reducing flame, pale-green, unaccom- panied by any smell.

Reduction film, black; sometimes dead, sometimes bright.

Oxide film, white ; moistened with a perfectly neutral solution of AgO,NOj, and then blown on by ammoniacal air, it gives a black spot which does not disappear in NHjO. If the film be first placed over bromine vapor the reaction cannot be obtained, owing to the oxidation of SbOs into SbOj. It is mialtered by SnCl., either with or without NaO, HO.

Iodide film, orange-red, disappearing by breathing, and reappearing by blowing or warming; blown on with ammoniacal air it disappears, but does not return. Gen- erally it gives the same reactions as the oxide.

Sulphide film, orange-red. The film is difficult to blow away with NH(S ; returns on blowing with air ; insoluble in water.

With soda on charcoal splinter gives no black stain on silver, but yields a white, brittle, metallic bead.

4. Arsenic Compounels, — i%i? coloration in upper reducing flame pale-blue, giving the well-known arsenical smell.

Reduction film black, dead, or brilliant ; thin film brown.

o.led by

Special Reactions. 237

Oxide film, white; touched with a perfectly neutral aoliition of AgO.NOi, and then blown with ammoniacal air, it gives a canary-yellow precipitate, soluble in NHO. Together with this yellow precipitate, a brick-red one of silver-arseniate occurs when the film has previously been treated with bromine vapor. SnCl., with and without soda, produces no change.

Iodide film is deep-yellow, disappears on breathing, but returns on drying ; disappears in ammoniacal air, and does not return ; reappears unaltered after the action of HCl.

Sulphide film, lemon-yellow, disappears easily on blow- ing with NH.S., and reappears on warming or blowing; insoluble in HO., and does not disappear by blowing upon it.

Reduction on charcoal splinter yields no metallic bead.

5. Bismuth Oomponnds. — Reduction film, black, dead, or brilliant ; thin portion of film, brownish-black.

Oxide film, light-yellow, unaltered by AgO.NOj, with or without ammonia; gives no reaction with SnCl., but yields black precipitate of BiOj on addition of NaO.HO.

Iodide film is very characteristic, and remarkable for the number of tints which it assumes. The thick part is of a brown or blackish-brown color, with a shade of lavender- blue ; the thin film varies from flesh-color to light-pink ; it easily disappears on breathing, and appears again on blowing. In a stream of ammoniac air it passes from pink to orange, and on blowing or warming it again attains a chestnut-brown color ; it resembles the oxide film in its beliavior with SnCl. and NaO.HO.

Sulphide film is of a burnt umber color ; the thin parts are of a lighter coffee-brown color ; does not disappear on blowing, and is not soluble in NHiS.

o.led by

238 Special Reactions.

On charcoal splinter with soda the bismuth compounds are reduced to a metallic bead, yielding, when rubbed in the mortar, bright, shining, yellowish splinters of metal soluble in NOj. The solution gives, with SnCl. and NaO. HO., black BiOj.

6. Mercury Compoimds. — Metallic film is mouse-gray, noncoherent, and spreads over the whole basin. To obtain small traces of Hg. in the reduced state, the sample is mixed with soda and KO,NOj and filled into a thin test-tube five to six millims. wide and ten to twenty mil- lims. long. This is held by a Pt. wire in the flame, whilst the bottom of the basin, filled with cold water, is placed close above the open end of the tube. If the quantity of Hg. is considerable, it collects in the form of globules, which can be seen with a lens, and which can be collected into larger drops by wiping the basin with a piece of moistened filter-paper.

Iodide film is obtained by breathing on the metallic film, and then placing it over the vessel (Fig. z6 of the Plate) containing moist Br. It first becomes black, and then disappears, but not until after some time ; HgBr. is formed. If the basin be now placed above the vessel of fuming HI., a very characteristic carmine-colored film of HgJ. is produced; this is often accompanied by Hgl., but neither of these disappear on breathing, nor when blown with aramoniacal air.

Sulphide film, black; not altered by breathing or by blowing with NH,S.

7. ThaUium Compouiids. — Since the minutest trace of this element can be recognized by means of the spectro- scope, it will seldom be detected in any other way.

Flame coloration, bright grass-green.

Metallic film, black, with coffee-brown coating.

o.led by

Special Reactions. 239

Oxidefilm, colorless; unchanged by SnCl., 01: NaO. HO., also with AgO.NOs with or without NHO.

Iodide film, lemon-yellow; insoluble in NH.O.

Sulphide film, obtained from the oxide film, black, with livid coating ; insoluble in NH,S,

On charcoal with soda, reducible to a white ductile grain.

8. Lead CompOUHlis. — Flame coloration, pale-blue.

Reduction film, black, dead, or brilliant.

Oxidefilm, bright ycllow-ochre colored ; stannous chlo- ride gives no reaction even on addition of NaO.HO ; AgO.NOa does not produce any reaction, either alone or on addition of NH4O.

Iodide film, orange- to lemon-yellow, insoluble on breathing or on moistening ; disappears on blowing with ammoniacal air, and again appears on warming.

Sulphide film, brownish-red to black; by blowing or moistening with NH.S. it retnains unaltered.

On charcoal splinter isiith soda gives a gray, very soft, ductile metallic bead, which is slowly but completely solu- ble in HO.NOj, yielding a white, easily crystallizable salt, soluble in HO., and precipitated as a white powder on addition of SO3 from a capillary tube.

9. Cadmium Compoimds. — Metallic film, black ; the thin parts, brown.

Oxidefilm, brownish-black, shading off through brown to a white invisible film of suboxide, which is not changed by SnCh, alone or with soda; AgO-NO produces a blackish-blue coloration of reduced metal, which is very characteristic and does not disappear on addition of

Iodide film, white ; no change produced by NH,0.

Sulphide film, lemon-yellow, insoluble in NH4O.

o.led by

240 Special Reactions.

Reduction on charcoal sflinier with soda. — The metal, owing to its volatility, can be obtained, only with diffi- culty, as a silver-whiLe ductile bead.

10. Zinc CompoiUtdS. — Reduction fiim, black; in the thin parts, brown.

Oxide film, white, and therefore invisible. To test it, a square centimetre of filter-paper moistened with NO5 is rubbed over the surface, and then rolled up on two rings on fine platinum wire, three millim6tres in diameter, and burnt. If the paper is burnt in the upper oxidizing flame at as low a temperature as possible, the ash forms a small solid mass about a square millimetre in area, which can be ignited without fusion, and becomes yellow on gently heating, and appearing white on cooling. If this be moistened with a few milligrammes of very dilute CoO. NOj solution and ignited, it appears of a beautiful green color on cooling; the same reaction can be effected with the metallic film.

Iodide film, white; not clearly recognizable either alone or after ammonia has been blown upon it.

Sulphide film, also white, and not easily recogiiiaed either alone or when moistened with NH,S.

Reduction on charcoal splinter does not proceed on account of volatility of the zinc.

11. Indluni Compounds. — Detected with most ease and certainty with the spectroscope.

Flame coloration, intense ; pure indigo-blue.

Metallic film, black, with brown coating ; at one time dull, at another brilliant. Disappears instantly with NOj.

Oxide film, yellowish-white ; scarcely visible ; give no reactions with SnCl. and AgO.NOj solution.

Iodide film, also yellowish ; nearly white, invisible, if weak, with and without a

o.led by

Special Reactions. 241

Sulphide film, also yellowish ; nearly white, scarcely visible. Unchanged by NHjS.

Reduction on charcoal splinter with soda takes place with difficulty, and affords silver-white, ductile globules, slowly soluble in HCl.

12. Iron Compoimda. — Reduction on charcoal splinter gives no metallic bead or ductile lustrous particles ; the finely divided metal forms a black brush on the end of the magnetized knife-blade ; this, when rubbed off on paper and dissolved in a drop of aqaa regia, yields a yellow spot when warmed over the flanie, which, when moistened with ferrocyanide of potassmtn, gne-. a deep coloration of Prussian Blue. The yellou spot moistened with NaO, HO., and then held for a few moments in a vessel with bromine vapor, gives, on a second addition of soda, no coloration of a higher oide

Borax Bead. — In the oxidizing flame, when hot, yel- low to brownish-red , when cold, yellow to brownish-yel- low ; reducing flame, bottle-green

13. Nickel {jmViVSL— Reduction on the charcoal splinter. — On pulverizing the charcoal, white, lustrous,, ductile, metallic particles are obtained, forming a brush on the magnetized blade. The metal, dissolved m NO5 on paper, gives a green solution, which on moistening with soda, exposure to bromine vapor, and second addition of soda, give a brownish-black spot of NiaOs, The ash of the paper, from which the soda has been washed out, can be used for the borax bead test.

Borax bead. — Oxidising flame, grayish -brown, or dirty-violet. Upper reducing flame, gray, from reduced Ni,, which often collects to a spongy mass of metal, ren- dering the bead colorless.

14. Cobalt Compounfls. — Reduction on charcoal splinter.

o.led by

242 Special Reactions.

— By pulverizing the charcoal, white, ductile, lustrous, metallic particles are obtained, which form a brush on the magnetic blade. The metal, rubbed off on to paper, gives a red solution when moistened with NO; this yields a green color on addition of HCl. and drying, which dis- appears again on moistening. The paper moistened with soda, brought into bromine-vapor and again moistened with soda, yields a brownish-black spot of CojO,. This reaction is plainly seen with a few tenths of a milligramme of metal. The paper can also be nsed, after washing out the soda and burning, for the coloration of the borax bead.

Borax bead. — Deep-blue bead in the oxidizing flame, which does not change in the lower reducing flame. When treated for a considerable time alone, or better still with plat in-chloride of ammonium, in the most energetic upper reducing flame, is completely decolorized, but only after long treatment, with the separation of cobalt or plat in -cobalt.

15. PaUadinm Compounds. — These are reduced upon fine platinum wire, with soda, in the upper oxidizing flame, to a gray mass, similar to platinum sponge, which, when rubbed in an agate mortar, gives shining, ductile, metallic scales. The scales, rinsed and dried upon a piece of glass plate, dissolve in NOs, with reddish-brown color.

If a small drop of a solution of cyanide of mercury is added to the liquid, a white flocculent precipitate is obtained, which dissolves in NH,0. when dropped upon it. After evaporation and boiling with aqua regia, the liquid, evaporated to a small drop, gives a dirty orjuige- yellow, crystalline precipitate of ammonio-chloride of palladium.

Solution of palladium is colored blue, green, and brown, by SnCl.j according to the amount used.

o.led by

Special Reactions. 243

16. PlatifiUm Compounds. — These give when ignited upon platinum wire with soda in the upper oxidizing flame a!so a gray spongy mass, which, by rubbing in an agate mortar, is converted into shining, silver-white, ductile metallic scales. These are insoluble either in NO5 or HCl. alone, but with aqua regia give a bright - yellow solution, if the platinum is pure ; if it contains rhodium, iridium or palladium, they give a brownish-yellow solu- tion. When solution of cyanide of mercury is added to the solution, and ammonia blown upon it, no locculent white precipitate is formed, but immediately a bright-yel- low crystalline precipitate of platin-chlorlde of ammonium,

SnCl. colors solutions of platinum yellowish -brown,

17. Iridium Compoimda. These, ignited in the upper oxidizing flame with soda, are likewise reduced to metal, which, when rubbed in an agate mortar, forms a gray pow- der, without lustre, and not in the least degree ductile. This is insoluble in nitric acid, hydrochloric acid, and aqua regia,

18. RliodiiiTn CompoTiiida. — These are only distinguished from the iridium compounds by the fact that the metallic powder, insoluble in aqua regia, when fused with bisul- phate of potassa, is partially oxidized, and affords a rose- red solution.

19. Osminm Compounds. — These give in the oxidizing flame volatile osmic acid, of a pungent odor, similar to chlorine, and which irritates the eyes.

20. Gold Componn. — If only traces of gold are pres- ent, mixed with a considerable quantity of gangue, it can only be concentrated and detected according to the old processes for detecting gold. Otherwise even a few tenths of a milligramme can be recognized by re- duction with soda on a charcoal splinter. The yellow,

o.led by

344 Special Reactions.

shining, ductile, metallic grain, obtained in tiiis way, can be reduced to spangles liaving the lustre of gold, by rub- bing in an agate mortar. These are insoluble in HCI. or NO5, but give, rather readily, with aqua regia, a bvight- yellow solution. If this is soaked up into a piece of blot- ting paper, and touched with SnCl., purple of Cassius is formed. What remains upon the glass is colored brown by a solution, of FeO.SO,, by reason of separated gold, whilst the liquid appears blue by transmitted light.

21. Silver Compounds. — If silver occurs only in traces in slags or complex ores, it can only be detected by the well-known method of cupellation. If, however, the silver compound is not mixed with a very large amount of for- eign matter, it can be detected in very minute quantities by reduction with soda on the charcoal splinter. The white ductile beads dissolve easily on warming in dilute NO5, and yield AgCl. with HCL, which can then read- ily be recognized by its behavior with NOj and NH,0. Less than one-tenth of a milligramme of silver can thus be easily detected with certainty.

22. Copper Compounds. — On the charcoal splinter with soda the copper compounds yield a ductile lustrous metal- lic bead, easily recognizable by its red copper color. By rubbing in the mortar, flat metallic particles aie obtained, which can be readily washed, and are easily soluble in NO5. The blue solution, absorbed on filter paper, yields a brown stain on addition of ferrocyanide of potassium. Instead of acting upon a metal in a curved glass, it may be dissolved by moistening paper upon which it is placed with NO,.

With borax onplatinum wire. — Blue bead, not altered to cuprous oxide when heated in the lower reducing flame alone, but on addition of very little tin-salt forms a red-

o.led by

Special Reactions. 245

dish-brown bead. If this bead be frequently oxidized and reduced in the flame, a ruby-red transparent bead is obtained ; this occurs most readily when the bead is allowed to oxidize very slowly.

23. Tin Componnds. — On the charcoal splinter the Sn. compounds are easily reduced to white, lustrous, ductile, metallic beads. The flattened particles, transferred to the curved glass, slowly dissolve in HCl. ; and the solution, when absorbed by paper, gives a red precipitate with selenious, and a black precipitate with tellurous acid dis- solved in HCl. If to the solution a trace of bismuth- nitrate be added, an excess of soda gives a black precipi- tate of BiO. The metal, acted on by NOi,, yields a white powder of insoluble SnOj.

A borax bead, containing enough CuO. to render it faintly blue, serves as a delicate test to ascertain with cer- tainty the presence of a trace of a Sn. compound, as the bead, placed in the lower reducing flame, turns reddish- brown, or forms a clear ruby-red glass.

24. Molybdenum Compounds. — On a charcoal splinter with soda are reduced, with great difiiculty, to a gray pow- der. In the same way some compounds give in the upper reducing flame a film on porcelain, which it is difficult to obtain. Molybdenum is best recognized as follows r

a. The sanipleis finely pulverized with the knife on the porcelain plate, is mixed on the hand with soda, obtains a pasty state by fusion. The mixture is then transferred to a spiral of fine platinum wire and fused in the flame. The liquid fused mass is then knocked off the wire and allowed to fall upon the plate, when it is digested with two or three drops of water, and the clear liquid above the sediment is soaked up into three or four strips of filter- paper, not too fine, several millimetres broad. One of

o.led by

246 Special Reactions.

these strips, moistened with HCl., does not change color, but with a drop of ferrocyaiiide of potassium is clianged to reddish -brown.

If one of these strips is gradually moistened with a few milligrammes of SnCl., it either becomes blue in the cold or upon warming ; if it becomes yellow or yellowish- brown, more of the solution of the test specimen m.ust be added by means of a capillary pipette, in order to cause the blue color to appear.

A drop of NH4S., placed upon the third strip, produces a brown color, and on addition of HCi., a brown pre- cipitate, whereupon the paper often becomes blue on the edge of the precipitate.

The yellow phosphate precipitate produced by the nitric acid solution of molybdate of ammonia can also be readily obtained. The slightly borax bead is colorless in the oxidizing flame ; when it contains more molybdenum bluish, enamel-like ; in reducing flame dark, by reason of reduced molybdenum.

25, Tungsten Compounds. — The reduction of tungsten can also be made on charcoal splinter with soda, but is not adapted to the separation or detection of the metal. The compounds are, therefore, treated in the manner just given for molybdenum, by soaking up the fluid, after fluxing with soda, with strips of filter-paper.

One strip moistened with HCl. remains white, but if heated turns yellow; moistened with ferrocyanide, un- changed. A second strip touched with SnCl. is colored blue even when cold or on warming. A drop of NH4S. causes no precipitate alone or with HCl. ; the paper, however, becomes blue or greenish on warming.

26. Titanium Oomponnds. — These give a colorless bead with microcosraic salt in the oxidizing flame, which turns

o.led by

Special Reactions. 247

a pale amethjtine color in the reducing flame. On addi- tion of FeO.SOj the bead assumes in the reducing flame the peculiar red color of venous blood, whilst in the oxi- dizing flame the light brown color of Fe.jOs can be ob- tained at pleasure. The titanium compounds form with soda a bead, which at first effervesces, and when hot is colorless and transparent, but on cooling becomes opaque. If to the hot bead SiiCl. be added, and if it then be heated in the lower reducin|; flame, a gray mass is formed, which dissolves on heating in HCl., yielding a pale amethystine -colored solution.

27, 28. Tantalum and Niobium Compounds.— These manifest the same reactions as titanium.

29. Silioa Compoimiis. — The silicates, when treated in the oxidizing flame with carbonate of soda, dissolve, more or less, with effervescence. The hot fused, when moistened with SnCl. and thoroughly ignited, does not give a trace of a blue coloration, when evaporated upon theporcelainplate, whereby the silica may be distinguished from titanic, tantalic, and niobic acids. It likewise fails to give the blood-red coloration in a bead with sesquioxide of iron, produced by these acids. The fluxed mass, if water and acetic acid are carefully added, and then evap- orated on the porcelain plate, separates gelatinous hydrate of silica. Fine splinters of silicate give, upon fusing in the bead of microcosmic salt, a gelatinous skeleton of silica, floating in the fused or cooled bead.

30. Chromium Compounds. — In platinum spiral with soda the compounds when fluxed, with the repeated addi- tion of nitrate of potassa, give a bright-yellow mass, which, when knocked off on to the porcelain plate and crushed, give a bright-yellow solution. If this solution is decanted from the residue, and acetic acid added, it becomes yel-

o.led by

248 Special Reactions.

lowish-red, and gives with lead salts, when it is soaked up by strips of filter paper, a yellow precipitate; with solu- tions of salts of oxide of mercury, a red one ; and with AgOjNOs, a reddish-brown one.

With NHjS., also by evaporation with aqua regia upon the porcelain plate, the solution becomes green ; likewise with SnCl. The iorax dead becomes emerald-green in the oxidizing flame, and does not change this color in the reducing flame,

31. Vanadium Compounds. — Treated with soda and nitrate of potassa in a platinum spiral yield a bright-yel- low mass, the solution of which, on addition of AgOfNOj and acetic acid, yields a yellow precipitate. The fused mass, when evaporated with aqua regia, gives a yellow instead of a green solution, which becomes blue on addi- tion of SnCl. If much vanadium is present, the solution gives a yellowish-brown solution or precipitate on addi- tion of concentrated cold HCl. In the borax bead these compounds give a yellowish-green color in the oxidizing flame ; in the reducing flame, a green color.

32. Manganese GoxirmRAs.— Borax bead. —Amethyst in the oxidizing flame ; colorless in the reducing flame.

With carbonate of soda on platinum wire, a bead is formed green after cooling, especially easily after addition of nitrate of potassa. Water extracts a green solution from it, which becomes red after the addition of acetic acid, and then, often with the separation of brown flakes, becomes colorless.

33. Uranium Compounds give a yellow bead in the oxidizing fiame, which becomes green in the reducing flame, especially on addition of SnCl. These colors closely resemble those of the iron compounds, but may easily be distinguished, at least If no other coloring raetal-

o.led by

Special Reactions. 249

lie oxide is present, by the fact that the uranium bead, when incandescent, emits a bluish-green light, analogous to that which the uranium compounds exhibit when fluor- escing. Beads of lead-oxide, stannic acid, and a few other substances, exhibit a similar phenomenon when incandes- cent, but they do not yield, like uranium compounds, a colored bead on cooling.

Heated gently on the platinum spiral with K0,2SOs, the insoluble uranium confounds can be decomposed. The melted mass is powdered with a few particles of crys- tallized carbonate of soda, and the moistened inass is absorbed hy filtering paper. A brown spot is formed by the addition of a drop of ferrocyaiiide of potassium to the moistened paper.

34. Pliospliorua Compoands. — These may easily be detected in its compounds, even when they are mixed with large quantities of other substances, as follows ;

The sample, having been ignited, is rubbed fine on the porcelain plate (see Fig. 25), and is then introduced into a small glass tube of the thickness of a straw ; into this tube, which is closed at the bottom, a piece of magnesium wire, about one-fourth of an inch in length, is placed so that it is covered by the powder. On heating the tube, magnesic phosphide is formed with incandes- cence. The black contents of the tube powdered on the plate give, on moistening with HO., the highly character- istic smell of HaP. A piece of Na. can be equally well used if the Mg. wire cannot be procured.

If it has been ascertained that the sample does not yield any film on porcelain in the upper oxidiiing fiarae, the phosphates may be recognized by heating on platinum with borax and a thin piece of iron wire in the hottest part of the reducing flame, when a bright moUen bead of iron

o.led by

250 Special Reactions.

phosphide is obtained, which can be extracted with the magnetized knife on crushing the bead tinder paper.

35. Sulphur Compounds. — On a charcoal splinter with soda, in the lower reducing flame, they give a fused mass, which, moistened upon a piece of silver, blackens it. Since selenium and tellurium produce the same reaction, the absence of these substances must be determined by the absence of a tellurium or selenium spot upon porcelain.

When only metallic sulphides are to be considered, and not sulphates, it will answer simply to heat the test speci- men in the flame to detect sulphur by the odor.

It will be sufficient to show the advantages of the methods described by one or two examples.

a. A mixture of sulphide of arsenic, sulphide of anti- mony, and sulphide of tin. — If in a mixture of these three sulphides, containing only traces of Sb. and Sn., they are separated according to the ordinary rules of qualitative analysis, by dissolving in alkaline sulphides and reprecipi- tation with acids, the detection of these two metals by the regular tests is extremely uncertain and troublesome. According to the following method the detection of these metals is rendered easy and certain when the proportion of Sn. is only a few thousandths, and that of the Sb. only a few hundredths rf the total weight of the mixture.

Th d g mm f 1 1 h d roasted on a

cu d p f 1 11 gh I Itogether sur-

rou d d by h fl m d h d ghing only a

fe m 11 g mi p d g h w h the knife.

Th n ed 1 1 d the end of a

thread of asbestos and a strong metallic film obtained on the test tube. In order to prevent the deposition of any carbon with the metals, which would act injuriously in the

Pieces of a thin chemical flask ate also best for use in this ca'e.

o.led by

Special Reactions. 25 I

subsequent operations, the upper reducing flame is made so small that the luminous point is only just visible. The film is next dissolved in a drop or two of NOs in the curved rim (Fig. 25, of the Plate), and the solution evapo- rated below its boiling-point by gently warming and blow- ing, so as to obtain the solid residue in as small a space as possible. A drop of neutral silver solution is now brought on to the residue at the moment when it becomes solid ; and on blowing with ammoniacal air a characteris- tic black stain is formed, whilst the reaction of As. is also generally noticed.

In order to detect Sn., a few scarcely visible particles of the roasted sulphides are fused on to a borax bead which has been very slightly tinted with cupric oxide. If the bead is now brought into the lower reducing flame, it becomes a ruby-red color from reduced cuprous oxide. If the oxide be present in too large a quantity, the bead can be obtained transparent by the process described under the reactions of the copper compounds. This reaction can only be obtained in the lower reducing flame of the non-luminous gas-lamp, as in the ordinary blow-pipe flame the cupric oxide is reduced to cuprous oxide without the presence of tin-salt.

Black tellurium, containing tellurium, selenium, anti- mony, gold, lead, and sulphur. — After the sulphur has been detected by the smell by roasting, the metallic film is obtained on a test-tube, which is then placed inside a wider and shorter tube containing a few drops of concen- A-(tfi sulphuric acid, so that the metallic film is surrounded by the acid. If the temperature be now gradually raised, the presence of tellurium is at once ascertained by the formation of a bright carmine color. If the temperature be still further raised, the tellurium oxidizes, and the oHve-

o.led by

252 Spectrum Anal Ysts.

green color of selenium becomes visible ; the cooled solu- tion, on dilution with water, then no longer exhibits the black precipitate of tellurium, but is colored yellowish-red with the selenium. If this is present in small traces only, it can be best detected by looking down the length of the test-tube upon a sheet of ivhite paper. As common com- mercial SO, often contains traces of selenium, it is well to make a trial experiment first. The antimony is detected as in preceding example. To detect the lead and gold, a sample is reduced on the charcoal splinter, the beads of tlie alloy are washed into a curved glass, and the flattened and dried metallic particles treatedwith rather strong NO5 3s long as anything dissolves. The acid is then evaporated off, and the soluble portion of the residue dissolved in a drop or two of water. The solution is brought on to a second curved' glass by means of a capillary pipette, and the characteristic precipitate of sulphate of lead obtained with SOj. The gold left undissolved as a brown powder, is completely washed by frequent addition of water and removal of the same with the capillary pipette. A por- tion of the dried particles of gold fused on a charcoal splinter with soda, yields in the mortar bright-yellow, golden particles, which may be dissolved in aqua regia and tested with SnCl. A centigramme of the sample is sufficient in experienced hands for all these n

Spectettm Anaiy8Is.

The second method— that of spectrum analysis, discov- ered by Kirchhoff and Bunsen, consists in letting the rays of the colored flame, after passing through a narrow slit, traverse a prism, and in observing the spectrum thus pro- duced by means of a telescope. Each of the metals which

o.led by

Spectrum Anal Ysis. 353

give color to the flame, thus yields a peculiar spectrum, lornied in some cases, as in that of baryta, of many con- tiguous colored lines ; in others of two more distant lines of different color, as shown by lithia ; or, again, of a sin- gle line, as in case of soda and thalhum. These spectra are characteristic in two respects, viz.: i, in the definite color of the spectrum lines ; and 2, in the invariable rela- tive position .they occupy.

The last-named fact enables us to detect, without diffi- culty in most cases, all the spectrum-giving ingredients of a mixture. Thus, when potassa, soda and lithia-salts are brought together into the spectroscope, the lines char- acteristic of each metal appear in the utmost purity at one view. Very minute traces of some elements do not, how- ever, exhibit their spectra in presence of large quantities of other substances.

The methods of obtaining the spectra of the elements, or their compounds, vary according to their volatility. The instrument or spectroscope used varies according to the degree of accuracy which the observations require. Thus, for the detection of some of the more commonly occurring substances, a rough apparatus ivith one prism will suffice, whereas for exact experiments, a much more powerfiil and perfect instrument is needed.

Every spectrum apparatus or spectroscope, exclusive of the source of light, is composed of an adjustable slit, a contrivance (collimating lens) for rendering the rays par- allel that have passed through the slit, and a prism. All light except that under examination must be excluded from the prism, and therefore the slit, prism, and lenses are enclosed in a tube, or, if the prism be too large, the latter is fitted with a separate cover. As the spectrum on emerging from the prism is but little longer than the

o.led by

254- Spectrum Anal Ysis.

width of the slit, and only becomes of some length as the distance from the prism increases? a magnifying glass is introduced, in order that the eye, though at but a small distance from the prism, may see the spectrum of a suffi- ciently large size, and the spectrum, therefore, is not observed with the naked eye, but through the medium of a telescope of moderate power. This telescope is also necessary for enabling the eye to receive the whole of the light passing from the collimating lens through the prisms.

In order to know the exact position of the lines an- other tiibe is added, in the end of which is placed a scale photographed on glass, and which is so reflected that the observer sees the scale and spectrum at the same

A small glass prism may also be attached to the end of the tube through which the colored flame is admitted, so that the spectra of two flames may be examined and com- pared at the same time.

Not only the number of the spectrum lines of a sub- stance, but also the degree of their intensity, is deserving of careful attention. As the brdliancy of the lines mcreases with the temperature, so, at, a rule, it is those lines which are particularly prominent at a high degree of tempera- ture that are the first to appear at a low temperature These are best suited for the recognition of a substance, and are therefore called charactenstic lines Such imea, according to their brightness, are designated m each sub- stance by the letters of the Greek alphabet, a, jS, y, 5, etc , being affixed to the symbol of the element.

The table at the beginning of the book exhibits the spectra of some of the more commonly occurring and easily recognized elements.

o.led by

Spectrum Anal Ysis. 255

— AH the volatile compounds of potassium, wlien placed in the flame, give a widely extended, con- tinuoiB spectrum, which consists of two chief lines; one line Ko, situated in the outermost red, and a second line, Kj3, situated far in the violet rays towards the other end of the spectrum.

When vapor of potassium is heated in the electric spark, several other lines make their appearance. Before testing potash silicateb they should be ignited with carbonate of soda, as it does not interfere with the reaction. Ortho- clase, sanidin, and adularia may be easily distinguished fiom albite, orthoclase, anorthite, and labradorite. If onlj a trace of potish is present, the '.ilitate should be heated with fluoiideol ammonium m a platinum dish, and the residue placed in a flame with a platinum wire.

Sodmm. — - The )cUow line, Naa, is the only one which appearsi in the sodium spectrum as seen in the flame with the ordinary spectroscope. With powerful instruments it is seen to be double. The line a, is remarkable for its definite form and brightness, and is produced by all the natural compounds of sodium.

LitMlun.— The salts of this metal give a bright line in the red, Li, and another much less distinct in the orange, Li/J. With high heat and strong prisms a blue line also appears. All lithium compounds give the reac- tion, and often only require to be held in the flame, as lepidolite, petalite, etc. If the amount is very small in the silicate it should be digested and evaporated with fluoride of ammonium, a little sulphuric acid added, again evaporated, and the residue treated with alcohol. The solution in alcohol is evaporated to dryness, the mass again treated with alcohol, and the liquid dried in a glass capsule. The crust formed can be placed in the flame with a platinum wire,

o.led by

256 Spectrum Anal Ysis.

Strontium. — The spectra, of the alkaline earths are more complex tlian those of the alkalies. Stitintium gives eight very distinct lines — six red, oae orange, one blue. The orange line, Sra, close to the sodium line, the two red lines, Sr and 7, and the blue line, SrS, are the most important. The chloride gives the best reaction, while the non-volatile compounds give none. The sulphate must be reduced to sulphide, by holding the bead in the reducing flame, and the silicates must be fused with car- bonate of soda, powdered and washed with water by decantation. The insoluble carbonate thus obtained is moistened with hydrochloric acid, and will then give a distinct reaction. The strontium lines do not interfere with the indications of the alkalies.

Oaleium. — The spectnim of this metal is easily distin- guished from all the foregoing by the green line, Ca, and by the orange, Ca. A feeble line is also seen in the violet with a powerful instrument, and other lines with increased heat. The chloride gives the best reaction. The non-volatile compounds must be decomposed by hydrochloric acid, and the silicates by fluoride of ammo- nium. The composition of calcareous rocks and minerals -is easily found.

Bariim. — The complicated spectrum of this metal is distinguished by its green bands, of which Baa and P are the most important. The haloid salts and more common natural compounds are recognized by holding them in the flame. The silicates must first be treated with hydrochlo- ric acid or fused with carbonate of soda and then dissolved in acid. If barium and strontium occur in small quanti- ties with calcium, the carbonates obtained by fusion are dissolved in nitric acid and the dried salt exhausted with alcohol. The residue contains only barium and stron- tium, which can generally be detected.

o.led by

Spectrum Anal Ysis. 257

RuMdium. — The continuous spectrum is not so ex- tended as tlat of potassium. The o and /3 are most bril- liant and best suited for the recognition of the metal. The lines 6 and y are leas intense but still very chaiacter- istic- These lines and even others appear with not only the volatile chloride, nitrate, etc., but even with the silicates.

GsBSium. — The spectrum is characterized by two lines, Csd and Csj3, both brilliant and well-defined. The absence of any line in the red distinguishes this from the two pre- vious spectra. With an intense light, yellow and green lines may be seen in the continuous parts of the spectrum. Rubidium and cesium can be easily separated from lithium and sodium by means of bichloride of platinum, but potassa is precipitated with them, and must be removed by repeated boiling with water before the presence of these two elements can be proved by spectrum analysis.

Thalliuia. — The compounds of this metal give a spec- trum with a single intense green line, Tl, which almost coincides with the 5 Ime of barium Meie traces of tlial- iium in pyrites maj be easily detected by simply heating them in the edge of the flame

Indium, — The spectrum is characterized by two lines. Inn, in the indigo, and Inp m the \iokt Tlie former is far the most intense, and sufficient foi the detection of the metal. To show ita pre'ience in sphalerite (zinc blende), the mmeia,! is roasted, decomposed by hydro- chloric acid, and the solution diluted and saturated with ammonia. The precipitate containing the oxide of indium is dried and a small portion of it moistened with hydro- chloric acid, and placed in the flame with platinum wire. The presence of Indium will be indicated by the blue line a.

It is not only those bodies which have the power of giving color to the flame which yield ciiaracteristic spec-

22* R.

o.led by

2gs SPECTRUM ANAL YSIS.

tra, for this property belongs to ail elementary substances, whether metal or non-metal, solid, liquid, or gas ; and it is always noticed when such element is heated to the point at which its vapor becomes luminous, for then each element emits the peculiar light given off by it alone, and the characteristic bright lines become apparent when its spectrum is observed. Most metals require a much higher temperature than the conimon flame, in order that their vapors should become luminous ; but they may be easily heated to the requisite temperature by means of the elec- tric spark, which in passing between two points of the metal in question, volatilizes a small portion, and heats it SO intensely as to enable it to give off its peculiar light.

Thus all the metals, — iron, platinum, silver, gold, etc. , — may each be recognized by the peculiar bright lines which their spectra exhibit.

The permanent gases also yield characteristic spectra, as hydrogen, nitrogen, oxygen, chlorine, carbonic oxide.

By placing gases, solutions of salts, etc., in glass ves- sels made for the purpose, and placing them between the illuminating flame and the slit in the tube, so that the light will pass through the gas or liquid, the so-called spectra from absorption are obtained. By this arrange- ment large portions of the complete spectrum disappear through absorption of corresponding rays of light, or else only dark lines are seen in different parts of the same.

Interesting phenomena of this kind are shown with solu- tions of certain salts of copper, cobalt, chromium, and per- manganate of potassa, and also of the rare metals erbium, didymiura, and yttria.

For a description of the great number of spectra which have already been carefully studied and mapped, reference

o.led by

Spectrum Anal Ys/S. 259

must be made to the laxge orks on this subject recently published and the or g al ne o as it is impossible to give, by a brief descr pt on any dea of the characteristic features of the masses of br gl t 1 nes constituting these spectra.

By this comparatively new and delicate method of analy- sis we succeed in obtaining a more accurate knowledge than we have hitherto possessed concerning the chemical composition of terrestrial matter, and also acquire infor- mation respecting the chemical nature of the sun, fixed stars, and distant nebulae, opening out the i of solar and stellar chemistry.

o.led by

.,t.db,

Tables

Showing The Behavior Of The Alkalies,

Earths, And Metallic Oxides, Alone,

And With Reagents, Before

The Blow-Pipe.

Ho.led by

262 Beiia Vior Of Alkalies And Earths.

TABLE t — BEHAVIOR OF THE ALKALIES AND EAETHS BEFOKE THE BLOW-PIPE.

AlkalUs.

Ahns on Platinum Wire.

I. Fotassa.

Ko.

RuniDiA. RbO.

CsO.

Color llie flame violet ; but even a minute quan- tity of soda destroys the reaction.

2. Soda. NaO.

Colors the flame intense reddish-yellow, even in the presence of a large excess of potassa.

3. LlTHlA.

LiO.

Colors the (lame carmine- red, even in the presence of potassa; but soda gives a yellowish-red.

4. Ammonia.

Nh,.

Combined with chlorine, nitric or sulphuric acids, it colors the flame very pale-green.

H.,t.db,

BEHA VIOR OF ALKALIES AND EARTHS. 263 TABLE I. — Continued.

Alone oa Platinum Foil.

No change.

In solution, change red litmus paper to tilue.

Wo change.

Turns the foil yellow when fused; but if washed and ignitec the color is destroyed, but the foil remains dull.

Pungent odor, colors red litnius

.,t.db,

Behavior Of Alkalies And Earths.

TABLE I.— Continued.

Alialies.

On Ch. alum, and in the forcep.

With Carbonate of Soda on Ch.

1. Baryta. BaO.

The Hydrate fuses, Iwils, inlumesces, and is finally absorbed by the Ch. The Caibonate foses readily to a transparent glass, which, on cooling, becomes en- amel-white. In the for- ceps it colors the outer flame ydlowish-green.

Fuses to a homogene- ous mass, which is ab- sorbed by tlie Ch.

z. Strontia. SrO.

The Hydrate behaves like hydrate of Baryta. The Carbonate fuses only on the edges, and swells out in arborescent ratifi- cations which emit a Iml liant light, and, when heatedwiththeR.Fl., im- part to it a reddish tinge ; shows after cooling alka- line reaction. In the for- ceps, colors the outci flame crimson.

Caustic Strontia is in- soluble. The Carbonate, mixed with its own vol- ume of Sd., fuses into a limpid glass, which be-

eooling. At a greater heat the moss boils, and caustic Strontia is formed, which is absorbed by the Ch.

3. Limb. CaO.

Caustic Lime is not changed. The Carbonate loses carbonic add, be- comes whiter and more luminous, and stows after cooling alkaline reaction. In the forceps it colors the outer flame pale-red.

Insoluble. The Sd. pass- es into the Ch., and leaves the Lime unaltered on its surface.

4. Magnesia. MgO.

Undergoes no alteration. The Carbonate becomes caustic .and luminous.

It behaves like Lime.

5. Alumwa. ATO'.

Not changed.

Forms an infusible com- pound, with slight intu- mescence. The excess of Sd. is absorbed by the Ch.

.,t.db,

BEHAVIOR OF ALKALIES AND EARTHS. lABLE I. — Continued.

With S. Ph. m I'latiiJun

WUh Bx. on I'atiman lUr

The Carbonate dissolves with, effervescence to a limpid glajs which, with a certain amount, be- comes opaque by flaming, with more, it becomes opaque white on cooling, even witlioul flirain

Readily dissolved to a limpid glass, which becomes opaque by flaming. The Carbonate dissolves with effervescence. On a large addition of Lime the glass becomes cloudy and crystallizes on cooling, but does not become enamel- white, like Baryta or Strontia.

Solulile in large quantities to a limpid glass which, when sufHcient Lime is present, becomes opaque by flaming. When saturated, the glass becomes enamel-white on

Readily soluble to a limpid glass, which becomes opaque by flaniing- When saturated, it becomes, on cooling, enamel -white.

Dissolves slowly to a limpid glass, which remains so on cooling, and which cannot be made cloudy by flaming, A laie quantity of Alumina makes the glass cloudy and nearly infusible; on cooling, it then assumes a crystalline snr-

Soluble to a limpid gli remains clear under all circum- stances. If too much Alumina is added, the undissolved portion be- comes transiucenL

o.led by

BEHAVIOR OF ALKALIES AMD EARTHS. TABLE I, — Continued.

Alkalies.

On Ch. alone, and in the forcep.

With. Carbonate of Soda onCh.

6. Glucina. BeO.

Not changed.

Insoluble.

7. Yttria. VO.

Not changed.

Insoluble.

B. ZlRCONIA,.

Infusible, but emitting a very glaring light.

Insoluble.

9. Eruia, EO.

The Oxide becomes lighter- colored and trans- lucent ra the R. Fl.

Insoluble.

10. Thoeia. TiiO.

Not changed.

Insoluble.

II. Silica. SiO,.

Not changed.

Soluble, with efferves- cence to a clear glass.

H.,t.db,

BEHAVIOR OF ALKALIES AND EARTHS. 267 TABLE I.— -Continued.

With Bx. on Flatinm Win.-

With S. Ph. on PlaHnum Wire.

Soluble in large quantiiies to a linipid glass, which becomes opaqtte by flaming. When Glu- ciiia is present in excess, jC be- comes enamel-white on cooling.

As with Borax.

Like Glucina.

Like Glucina.

Like Glueina.

Dissolves more slowly than with Borax.

Dissolves slowly to a clear glass, which becomes opaque by flaming, or on cooiing if in excess.

As with Borax.

In small quantify dissolves to a clear glass, which becomes enamel- white on cooling if in excess; if clear, it cannot be made opaque by flaming.

As with Borax.

Dissolves slowly to a limpid glass, diflcultly fusible, and can- not be made opaque by flaming.

to a limpid glass.

The insoluble portion becomes translucent.

H.,t.db,

Behavior Of Metallic Oxides.

TABLE n— BEHAVIOR OF THE METALLIC OXIDES BEFOEE THE BLOW-PIPE,

Metallic Oxides

in Alphabetical On Charcoal alone. Order.

I. Teroxide op Antimony, or Antimonous

2. Arsenous AsO'.'

4. Oxide of

Cadmium.

CdO.

O. Fl,! It is displaced, and deposited upon other part of the Ch.

R. Fl.: It is reduced and rolatiiized. A Ct. of imonous add is deposited the Ch., and a ereenish- )!ue color imparled to the

With Carbonate of Soda.

On Ch. very readily re- duced in O. Fl. and R. Fl. The metal fumes and coats the Ch. with oitide of An-

On Ch. reduced, with

fumes, which a terized by a sti

O. Fl. : On platinun fuses readily to a dark- brown mass, which cooling, becomes pale yel- low.

On Ch. in O. Fl. and R. Fl. reduced to metallic bismuth, which, with long t Wowing, vaporizes, coat ing the Ch. with yellow oxide. Tile Ct., when touched with the R. Fl., disappears without color-

O.Fl.: On platinum foil unchanged.

R.Fl.: On Ch.it disap- pears in a short time, and deposits all over the Ch, a dark-yellow or reddjsh- brown powder; the Color can only he clenrly dis-

O, Fl.: Insoluble, R. n.; On Ch readily reduced ; the metal vapor- izes and deposits a dark- yellow or reddish-brown a. on the Ch. The more remote portion of the coal

.,t.db,

Behavior Of Metallic Oxides. 269

TABLE n. — Continued.

With Bx. on Platinum Wire.

O.FI.; Dissolves in large quan- tiEies to a limpid glass, which, while hot, appeais yellowish, but after cooling, colorless,

R. FL: The glass, when treated only for a short time in the O. Fl., becomes on Ch. grayish and cloudy from particles of reduced antimony. With tin it becomes gray or black, according to the degree of salura-

With S. Fk. on FlaHmim Wirt.

O. Fl.: Dissolves with efferves- cence lo a limpid glass, which, while hot, is slightly yellowish.

R. Fl.: On Ch. the saturated bead becomes at first cloudy, but after- wards clear again, owing to the volatilization of the reduced anti- mony. Treated with tin, the glass becomes, after cooling, gray, even if but very little antimonous oxide is present. With strong blowing

O.FI.: Asniall quantity is easily dissolved to a clear yellow glass, which, on cooling, becomes color- less. On a large addition of oxide, the glass, while hot, is yellowish- red, becomes yellow on cooling, and when cold is opalescent. '

R. Fl.: On Ch. the glass becomes at first gray and cloudy, the oxide is reduced to metal with efferves- cence, and the bead iiecomes clear again. An addition of tin accel- . erates the process.

O.FI.; Soluble in large quantity lo a limpid yellowish glass, becom- ing almost colorless on cooling. When highly saturated, it may be made enamel-white by flaming, and when still more oxide is pres- ent, it becomes by itself enameU white on cooling.

R. Fl.! Placed on Ch., it enters into ebullition; the oxide is re- duced; the reduced metal vapor- izes immediately and deposits a dark-yellow Ct.

0. FL: Readily dissolved to a limpid yellow gla,ss, which, on cooling, becomes colorless. When a greater quantity of oxide is pres- ent, the glass may be made enamel- white bv flaming, and on a still lair addition it becomes by itself enamel-white on cooling.

R. Fl.: On Ch„ particularly when tin is added, the glass remains colorless and limpid while hot, but becomes, on cooling, dark-gray and opaque.

0. Fl.: Soluble in large quantity toa limpid glass, which, whilebot, is yellowish, but colorless when cold; when saturated, it becomes enamel-white on cooling.

R. Fl.; On Ch., the oxide be- comes slowly and imperfectly re- duced. The reduced melal de- posits a very feeble Ct. of dark- yellow color. The color is only clearly seen when the mass is cold. An addition of tin facilitates the

23*

o.led by

270 Behavior Of Metallic Oxides.

TABLE II. — Continued.

MaaUii Oxides ia Alphabetical

On Charcoal alme.

With Carhmate of Seda.

S- Sesqot OXIDE

OF QSKItTM.

CeW.

The protoxide is con- verted into sesquioxide, CeO' by the 0,F1., which remains unaltered in the R.FI.

Insoluble. The Sd. passes into the Ch. ; the sesquioxide is reduced to protoxide, which remains the Ch. as a light-gray

6. .Sesquioxide OF Chromium

Not changed in the 0. Fl. or R. Fl.

O.Fb On platinum wire soluble to a dark yellow- ish-brown glass, which on cooling becomes opaque and yellow. (Chromic acid.)

R. Fl.: The glass be- comes opaque and green on cooling. On Ch. it cannot be reduced to melaJ; the Sd. passes into the Ch., and the oxide remains behind as a green powder, CrO'.

7. Protoxide

OK Cobalt.

CoO.

0. n.: N t b g d R. Ft,: It IS du d t metal, but 1 t fus the mass tt t d by

metallic lustre by friction.

0. FL: On platinum w re a very small quantity-

dissolved to a transpa-

it mass of a pale red- dish color, which on coot- g becomes gray.

R. FL: On Ch. reduced to a gray mEnetic pow- der.

.,t.db,

Beiia Vior Of Metallic Oxides. 27 1

TABLE n.~ Continued.

With Bx. on Platmum Wire.

Wilh S. Ph. on Platinum Wire.

0. Fl.; Soluble to a limpid glass of dark-yeEow or red color, which changes on cooling to yellow. When highly saturated with oxide the glass becomes, on cooiing, enamel- white.

R.Fl.: Theyellow glass becomes colorless. A highly saturated iiead becomes on cooling enamel-white and crystalline.

0. Fl.: As with Ex., but on cool- ing, colorless.

R. Fl.: Perfectly colorless, hot and cold, thus being distinguished from a sesquioxide of iron glass. Becomes never opaque on cooling, however large the amount of oside.

0. Fl.: Dissolves but slowly, but colors intensively. If little of the oxide is present, the glass, while hot, is yellow ; when cold, yellow- jsh-greenj with more oxide it is dark-red while hot, becomes yel- low on cooling, and when perfectly cold has a fine yellowish-green

R. Fl.: The giass is green, hot and cold. The intensity of the color depends on the amount of oxide present. Tin causes no change.

O.FL: Soluble toalimpidglass, which, while hot, appears reddish ; when cold it has a fine green color.

R.FL: As in O.FL

0. Fl.: Colors very intensively. The glass appears pure smalt-blue, hot and cold. An excess of oxide imparts to tlie bead a deep bluish- black color.

R. Fl.; As in O. Fl.

0. Fl.: As with Ex., but for the same quantity of oxide the color ii not quite so deep,

E. FL: As in 0, Fl.

.,t.db,

272 Behavior Of Metallic Oxides.

TABLE n, — Continued.

Metallic Oxides

in Alfhabelical

Order.

On Charcoal alone.

WUh Carbonate of Soda.

8. Oxide of

Copper,

CuO.

0,F1.: Fuses toablack globule, which becomes reduced where it is in contact with the Ch.

R, Fl.: Reduced tometal at a temperature below the melting-point of cop- per. When tVie heat is increased a globule of me- tallic gopper is obtaiued.

0. Fl: On platinum wire soluble to a limpid

cooling it becomes opaque

""r.'fI.: On Ch. easily re- duced to metal, which, when the temperature is sufficiently high, foses to one or more globules.

9. Sesquiqxipe

OF DlBYMlOM.

Infusible in the O. Fl. In R. Fl. loses its brown color and becomes gray at a high temperature.

Insoluble. The soda is absorbed by the coal, and the gray oxide re- mains behind.

10. Teroxide

OF Gold.

AuO'.

tion il becomes reduced to metal in O. Fl. and R. Fl. The metal fuses easily to a globule.

Does not dissolve in the Sd., but is easily reduced in both flames. The metal fuses readily to a globule. The Sd. passes into the Ch.

II. OxinE OF

dark-yellow when heated, but on cooling is again lighter, and does not fuse. In the R. Fl. is gradu ally reduced and volatil- ized, depositing a coat on the coal. A distinct vio- let flame is produced.

In the 0. Fl. insoluble.

In IheR.Fl. is reduced on coal, and the metal partly volatilizes, coating the coal with oxide, while a portion may be seen as almost silver-white glob- ules in the fused salt

Iriwiim.

At a red heat becomes reduced; the reduced metal is infusible.

O.Fl.: Does not dissolve in the Sd., but becomes reduced ; tlie metal cannot be fused to a globule.

R, Fl ; As in O, Fl.

.,t.db,

Behavior Of Metallic Oxldes.

TABLE n. — Continued.

Wilh Bx. on Pla/mum iViri. WUh S. Ph. on Platm:

O. Fi.; A small addition of oxide makes the glass appear green while tot, but blue when coid. A laie quantity imparts to it a very deep-green color while hot, becoming greenish-blue when cold.

R. Fl.: A glass containing a cer- tain quantity of oxide becomes colorless, but on cooling becomes opaque and red (suboxide). On Ch. the copper may be precipitated in the metallic state, the bead be- coming in consequence colorless. A glass containing protoxide, when treated on Ch. with tin, becomes on cooling brownish - red and opaque.

which in the moment of reffigeration changes suddenly to brownish red and opaque. A glass containing but little oxide, when treated on Ch. with tin, ap- pears colorless while hot, but he- comes brownish-red a.nd opaque

In the O. Fl. soluble to a cleai rose-red glass, and remains unal- tered in the R. Fl.

As wilh Crbonato of Soda.

Dissolves with more difficulty than in borax, but when strongly saturated is distinctly rose-red.

As with Carbonate of Soda.

In the 0. Fl. dissolves to a clear glass, feebly yellowish while hot, colorless on cooling, and cloudy when much is added.

In the R. Fl. the glass is un- changed. On coal the oxide is reduced, volatilizes and coats the coal again with oxide. The flame

As with Borax, but Hie hen treated wilh tin on coa omes gray and cloudy on cot

As wilh Carbonate of Soda.

As with Carboiia

.,t.db,

2/4 Behavior Of Metallic Oxides.

TABLE IL — Continued.

Metallic Oxiiles

in Alphabetical

Order.

On Charcoal alone.

With Carbonate of Soda.

13. Sesquioxide

0. FL: Not changed. R. Kl : Becomes black and magnetic.

0. Fl.: Insoluble.

R. ri.; On Ch, it is re- duced; the mass, when placed in a mortar, pul- verized, and repeatedly washed with water to re- move the adherent Ch. particles, yields a gray

attracted by the magnet.

14. Oxide of

Lanthanum.

Unchanged.

Insoluble, The soda is absorbed by the coal, leav- ing the gray oxide behind.

15. Oxide of Lead. PbO.

Minium, when heated on platinum foii, blackens; on increasing the temper- ature it changes into yel- low oxide, which finally fuses to a yellow glass.

OnCh.inO. Fl. andR. Fl. almost instantaneously reduced to metal which, with continued blowing, vaporizes, and covers the Ch. with yellow oxide, surrounded by a faint white ring of carbonate. The Ct., when touched with the R. Fl., disap-

flame an azure-blue tinge.

0. Fl.: On platinum wire readily dissolved to a limpid glass, which, on cooling, becomes yellow-

R. Fl.: On Ch. reduced to metal which, with con- tinued blowing, covers the Ch. with oxide.

.,t.db,

BEHAVIOR OF METALLIC OXIDEH. TABLE ir. — Continued.

With Bx. on Platinum Wire.

With S. Ph. on Platinum Wire.

0. FI.: A small amount of oxide causes the glass to look yellow while hot, colotlesB when cold. When more of the oxide is present the glass, while hot, appears red, and yellow when cold. A still larger quantity makes the glass dark-red while hot, and dark-yel- low when cold.

li. Fi.: The glass becomes bot- tle-green. Treated on Ch. with till it becomes, at first, bottle-green, but afterwards pure vitriol -green.

of saturation the glass, while hot,

comes on cooling at first yellow, then greenish, and finally colorless. On a very large addition of oxide it appears, while hot, deep-red, becoming, on cooling, brownish- red, then of a dirty-green color, and finally less brownish -ted.

R, Fl.: A glass containing but little of the oxide suffers no visible change. When more of the oxide is present il is red while hot, and on cooling becomes at first yellow, then greenish, and finally reddish. Treated with tin on Ch. the glass on cooling becomes at first green, and finally colorle.ss.

In the 0. Fl. dissolves to a dear, colorless glass, that becomes en- amel-white by flaming when satu- rated to a certain extent, and when strongly saturated be com ea enamel- like of itself on cooling.

In R. Fl. the same as in 0. Fl.

As with Borax.

0. Fl.: Easily solnble to a limpid yellow glass which, on cooling, becomes colorless. If much oxide is present it may be made cloudy by flaming. A still laier addition of oxide causes the bead to be- come enamel-yellow on cooling.

R. Fl.! The glass diffuses itself over the Ch. and becomes cloudy. With continued blowing the oside is reduced to metal, with eflerves- cence, and the glass becomes clear again.

O. Fl.: As with Bx, But to ob- tain a glass which appears yellow M-hile hot, a large addition of the oxide is required.

R. Fl.! On Ch. the glass be- comes grayish and cloudy. This

when tin is added ; but the glass can never be made quite opaque. If much of the oxide is present, the Ch. becomes coated.

.,t.db,

BEIIA VIOR OF METALLIC OXIDES. TABLE II, — Continued.

On Charcoal ahne.

With Carbonate of Soda.

16. Sesquioxide OF Manganese.

O.Fl,; Infusible. When Ihe temperature is suffi- ciently liigli, both the ses- quioxide and the peroxide are converted into a red- " " " " (MiiO

e effect.

+ MnW). R. Fl.; The sj

Fl.: On platinum or foil a very small quantity dissolves to a transparent green mass, which on cooling becomes opaque and bluish-green. R. Fl.: On Ch. it can-

the Sd. passes into the Ch. and leaves the protoxide behind.

17. Protoxibk

OF Mercury.

HgO.

. Molybdic

MoQS.

O. Fl.; Fuses, becomes brown, vaporizes, and de- posits on the Ch. a yellow Ct., which nearest to the assay is crystalline. On cooiing the Ct. becomes white, and the crystals colorless. Beyond this I thinner non- vola- tile fiim of hinoxide, which )n cooling is dark cop- )er-red, with metallic lus-

it. Fl.:Thegreaterpart of the assay is absorbed by the Ch., and may be reduced to metal at a suf- ficiently high tempera- ture; the metal is in the shape of a gray powder.

Healed in a matrass to dness, it is reduced and porized. The vapors 'n the neck of the matrass and form a metallic coating, which can be united to a globule by carefully tapping on the matrass.

O. Fl.: On platinum wire dissolves with etier- vescence to a limpid glass, which on cooling becomes milk-white.

R. Fl.: Fuses with ef- fervescence. The fused mass is absorbed by the Ch., and part of the acid is reduced to metal which may be obtained as a steel- gray powder.

.,t.db,

Behavior Of Metallic Oxides. 2//

TABLE n. — Contiiraed,

With S. Ph.

Flah

t Wire

O. Fl.; Colors very intensivel)'. The glass, while hot, is violet, on cooling it assumes a reddisli tinge. When much manganese is added, the glass becomes quite black and o|)aque; but the color can be seen when the glass, while soil, is flat- tened with the forceps.

R. Fl.: The glass becomes col- orless. If Ihe color was very dark; the phenomenon is best observed on Ch. with addition of tin.

O. Fl.: A considerable addition of manganese must be made to produce a colored glass; it then appears, while hot, brownish- vio- let, and reddish- violet when cold, but never opaque. If the ghiss contains so small a quaJitity of manganese that it appears color- less, an addition of nitre will pro-

A glass containing oxide bubbles and yields gas at a high tempera-

, Fl.; Becomes very soon col-

O. Fl.: Dissolved in taiquan: titles to a limpid glass which, while hot, appears yellow, but colorless on cooling. A very large amount of acid causes the glass to appear dark-yellow while hot, and opaline when cold.

good flame black nocks of K separate, and are visible in yellow glass, if pinched flat.

O. Fl: Easily soluble lo a lim- pid glass ; if but little of the acid IS present it is yellowish-green while hot, but when cold almost colorless. On Ch. the glass be- comes very dark, and on cooling assumes a beautiful green color.

K.FI.: The glass assumes a very dark, dirty-green color which, on cooling, becomes tieautiful bright- green. The same on Ch.; tin deepens the color a little.

.,t.db,

BEHAVIOR OF METALLIC OXIDES. TABLE U.— Continued.

Metallic Oxides

in Alphabetical

Order.

On Charcoal alone.

With Carbonate of .Soda.

19. Protoxide

OP Nickel.

NiO.

0. Fl.! Not changed.

R. Fl,: On Ch. reduced to metal i the spongy mass cannot be fused to a glob ule, but assumes metallic lustre by friction; it is attracted by the magnet.

0. rl.: Insoluble.

E, FL: Easily reduced to metal, in the shape of bright, wbiie scales, which are attracted by the mag- net, if the panicles of coal are washed away.

20. NiOBIC

Acid. NbO'.*

In 0. Fl. becomes yel- lowish, bm white again on cooling.

In R. n. the same.

In 0. Fl., with equal volume of soda, fuses with effervescence ; with more soda, sinks into the coal.

In R. Fl. the same. It cannot be reduced to metal.

21. huponiobic Acid.

Like Niobic Acid.

Like Molybdic Acid.

Id have the formula NbOs.

Ho.led by

BEHAVIOR OF METALLIC OXIDES. TABIE n.— Contmued,

n PlaHnam Win.

With S. Ph. on Platinum h

cold, pale reddiab-brown. More oxide makes Che coloration deeper. R. Fl.: The glass becomes gray and cloudy, or even opaque. With continued blowing the minute par tides of reduced metal collect to- Eethet and the glass becomes col- orless. Tbb takes place more readily on Ch., especially when tin is added. The nickel then unites with the tin to a globule.

In O. Fl. dissolves easily clear, colorless glass, becoming opaque by flaming with a certain addition, and with more becomes opaque of itself whei

In R. Fl. a glass which, aller treatment in the O. Fl., becomes opaque of itself, on cooling maining unaltered.

O.FL: Soluble toareddishglass which, on cooling, becomes yellow. A latter addition causes the glass to appear brownish-red while hot, and reddish-yellow wheti cold.

R. Fl.i On platinum wire not changed. On Ch. with tin it be- first, gray and opaque;

ued blou

the I

In O. Fl. dissolves lareely to a clear glass, yellow while hot, but colorless on cooling.

In R. Fl. with a large addition the glass becomes brown. The addition of sulphate iron gives a blood-red bead.

tion of avery large amoiiut.ci made opaque by flaming.

In R. Fl. a glass formed in the O. Fl., which opal esces on cooling, becomes clear again. With more it becomes cloudy, and bluish-gray on cooling; with a very V, amount it becomes quite ops and bluish-gray.

:id prepared from the ses- quichloride behaves as follows:

In O. Fl. in laie quantities it

dissolves to a greenish-blue glass,

which on continued blowing be-

.mes clear and colorless.

In R. Fl. becomes pure blue (on

coal pale-brown), and with addi-

"on of sulphate of iran blood-red.

Prepared from Coiumbite di-

jctly, yields only a brown glass

a the:

;r flame.

o.led by

Behavior Of Metallic Oxides.

TABLE II. — Continued.

Metallic Oxides in Alphabetical

On Charcoal alone.

With Carbonate of Soda.

Z3. BiNOXIDEOF

Osmium. OsO".

0. Fl.: Converted info osmic add which, with- out depositing a Ct., vol- atiliics with its peculiar pungent odor.

R. Fl.: Easily reduced to a dark-brown and in- fusible metallic powder.

Easily reduced to an infusible metallic powder, which roay be obtained pure by washing away the coal.

OF Palladium. PdO.

Reduced at a red heat; but the metallic particles are infusible.

ea into the Ch., and leaves the Palladium behind as an infusible powder.

34-IiiNOX.DKOF

Platinum.

Like Palladium.

Like Palladium.

25. Sesqui Oxide

OF Rhodium.

Like Palladium.

Like Palladium.

26. .Sfsqui Oxide

OP Ruthenium.

Like Palladium,

Like Palladium.

27. Oxidr Of

Ago.'

Easily reduced to me- tallic silver, which unites to one or more globules.

Instantly reduced. The Sd. passes into the Ch., and the metal unites to one or more globules.

z8. Tantauc Acid. TaO.

In 0. Fl, becomes slight- ly yellow, but is while again when cold. In K.. Fl. the same.

than an equal volume of soda fuses on coal to a bead with effervescence, and soon spreads out; with more soda sinks into the coal.

In R. Fl. the same. It cannot be reduced to metal.

.,t.db,

Behavior Of Metallic Oxides.

TABLE II. — Continued,

With Bx. OH Platinum Wire.

With S. Fh- on Platinum. Win.

O. Fl. and R. Fl.: Reduced, but not dissolved ; the meiallic par- ticles cannot be fused lo a globule.

As with Ex.

Like Palladium.

Like Palladium.

Like Fa!ladiiim.

Like Palladium.

Like Palladium.

Like Palladium,

0. Fl.i In part dissolved, and in part reduced. On cooling, the glass becomes opalescent or milk- white, according to the amount of oxide present,

R. Fl.: The glass at first be- comes gray, bul afterwards limpid and colorleas.

0. Fl.: Imparts to the bead a yellowish color. When much of the oxide is present, the glaas.when cold, is opalescent, and appears yellowish af daylight, reddish at candle-lighi.

R. Fl,: As with Bx.

In O, Fl, dissolves easily to a clear glass, which with a certain amount appears yellowish while hot, colorless on cooling, and can be made opaque by flaming. With still more the glass becomes enam- e!-wMte of itself on cooling.

In R. Fl. same as in 0. Fl.

In O. Fl. dissolves largely to a clear glass, which with a very lai amount is yellowish while hot, but colorless on cooling.

In R. Fl. the above glass is un- changed.

.,t.db,

BEHAVIOR OF METALLIC OXIDES. TABLE II. —Continued,

MitaUic OxuUs

in AlfihabelUal

Order.

On Charcoal alons.

Wilk Carbonate of Soda.

29, Tellukous Acid. TeO=.

0. Fl.! Fuses, and Is re- duced with effervescence. Tfie reduced metal be- comes instantly vaporised and covers the Ch. with tellurous acid; the Ct. usually has a red or dark- yellow edge,

R.n,! AsinO.Fl.;the outer flame appears of a bluish -green color.

Soluble, on platinum

wire, to a limpid and

colorless glass, which on

cooling becomes white.

On Ch. reduced and

a. of tellurouB acid.

30. BlNOXIDEOF

SnO".

0. Fl: The protoxide bui-ns, like tinder, to bin- oside. ITie binoxide be- comes very luminous and appears, while hot, yel- lowish, but assumes on cooling a dirty-whif e

R.F1.: With a powerful and continued flame it may be reduced to metal, a trifling of SnO' being formed near the metal.

0. Fl.; On platinum wire it forms with Sd., with effervescence, an in-

R.Fl.: On Ch. reduced to metallic tin.

31. Titanic Acid.

0. Fl.; Assumes, on heating, a yellow color and becomes white agaii on cooling. Suffers no other change.

E. Fl.: AsinO. Fl.

0. Fl.; On Ch. it dis- solves, with effervescence, to a dark-yellow glass, which, on cooling, crys- tallizes, and thereby evolves so much heat that (he globule glows again strongly. When cold it is grayish-white to white.

R. Fl.: AsinO. Fl.; can- not be reduced to metal.

.,t.db,

Behavior Of Metallic Oxides. 283

TABLE n. — Continued.

Wm Bx. m Platinum Wire

O. Fl.: Soluble to a limpid and colorless glass which, on Ch., be- comes gray from reduced metal.

R. Fl,: On Ch. becomes iit first gray, afterward colorless. TheCh. becomes coaled with (ellurous acid.

O. Fi.: A very small quantity dis- solves slowly to a limpid and color- less glass, which remains so on cooling, and not becoming opaque by flaming

R. Fl.; From a highly saturated glass a part of the oxide may be reduced on Ch.

O. Fl.; Easily soluble to a limpid glass which, when containing krge quantity, appears yello' while hot, but becomes colorlei on cooling. When contidmng very laie quantity it is enamel- white when cold.

R. Fl.: When containinj, little titanic add the glass becomes yellow; when more, dark-yellow to brown, A saturated glass ' comes enamel-blue by flaming.

With S. Ph. on Piatt

o

Fl

Aaw

thU

rax

K

n

. The

fl'ers n

or pi

umwi

O. Fl.: Easily dissolved to a limpid glass which, when contain- ing a large quantity, appears yel- low while hot, but becomes color- less on cooling.

R. Fl.! Appears yellow while hot, but, on cooling, reddens and finally assumes a violet color. If iron is present the glass, on cool- ing, becomes brownish-red; with

-if the I

It of tit

1 Ch.

o.led by

284 Behavior Of Metallic Oxides.

TABLE II. — Contimied.

'Gallic Oxides

n Alphabetical

Order.

33.SESQmoxrDE OF Uranium.

O, Fl.: Infusible; but assumes a dirty yellow- ish-green color.

R. F!.; Blackens, owing to the formation of prot-

;s into the Ch. Tlie assumes the lustre and color of graphite.

Wilh Carbonate of Soda.

O. Fl.! On platii it dissolves to ! and deep-yellov which, on cooling, be- comes crystalline and opaque, and of white or yellowish color.

R. Fl.! With very little Sd. 00 Ch, it is reduced to metal-, vi-ith more Sd. it forms a yellow compound of metallic lustre which passes into the Ch.

O. Fl.: Insoluble. With & certain amount of Sd. the mass becomes yellow- ish-brown, and widi more passes into the Ch.

R.Fl.! A5inO.F!.;no reduction to metal takes place.

o.led by

BEHAVIOR OF METALLIC OXIDES. TABLE n. — Continued.

n Flatinum Wire.

'I Platinum Wire.

O. Fl.: Like titanic acid.

R. Fl.! A glass, containing but little tungstic acid, is not changed. When more, it becomes yellow, and, on cooling, yellowish- brown. On Ch. tlie same reaction is pro- duced with a less saturated bead. Tin deepens the colors.

O. Fl.: Easily dissolved (o a limpid and colorless bead, which, when highly saturated, appears yellow while hot,

R. Fl.: With little blowing the glass appears, while hot, of a dirty green color, blue on cooling; wi strong blowing it becomes, on cooling, bluish-green. On Ch, with tin, deep green. If iron ia present the glass, on cooling, be- comes brownish-red; with tin on Ch. the glass becomes blue or, if the amount of iron is considerable,

O, Fl.: Behaves like sesquioxide of iron. When highly saturated ! O. Fl.; Dissolves to a limpid the glass may be made enamel- yellow glass, which, on cooling, yellow by flaming. tiecomes yellowish-green.

R,F1.: Behaves like sesquioxide R. Fl.: The glass assumes a ofiron. The green bead, when at I dirty green color which, or — '

1 point of saturation, may be made black by flaming. On Ch. with tin it be comes, dark-green.

O. Fi.: Dissolved to a Hmpid glass which, when the quantity of vanadic acid is small, appears col- orless, when larger yellow, and which, on cooling, becomes green-

ish.

O. Fl.! Soluble to a limpid lass which, if sufficient vanadic acid is present, appears dark-yellow while hot, and becomes light-yellow on

""""isli, and assumes a tine

, color (

o.led by

286 Behavior Of Metallic Oxides.

TABLE IL — Continued.

Melallu Oxides

in AlfhabeHcal On Charcoal aione. WUh Cto-bonate of Soda.

Order.

35- Oxide oi Zinc. ZiiO.

O. n.: When heated becomes yellow, and, on cooling, white again. It '"uses not, but becomes

R. Fl.: Is alowiy re- duced ; the reduced metal mes rapidly re-oxi- dized and the oxide de- posited on another pli of the Oi., being yello ish while hot, and wli moling.

0. Fl.; Insoluble.

R, FL: On Ch. it be- comes reduced. The metal vaporizes and coats the Oi. with oxide. With

,pow.

le the char-

o.led by

BEHAVIOR OF METALLIC OXIDES. TABLE 11 — Continued.

Platinum Wirt. With S. Fk. on Platinum Wire.

O. Fl.! Dissolves readily, and in lai quantity, to a limpid glass, which appears yellowish wMle hot; on cooling it is colorless. When much of the oxide is present, the glass may be made enamel-white by flaming; and on a still laigei addition it becomes enamel-white on cooling.

R. Fl.: The salurated glass be- comes at first gray and cloudy, and finnlly transparent again. On Ch. the oxide becomes reduced, the rnetal vaporizes and coats the Ch. with oxide.

.,t.db,

288 Arrangement Of Metallic Oxides.

TABLE in— THE METALLIC OXIDES ARRANGED

With Reference To The Colors Which

They Impart To The Fluxes.

With Borax in the Oxidizing Fl-

i. — Colorhss Beads.

When feebly satura'

Silica, Alumina, Binoxide of Tin, Baryta, Sirontia, Lime, MaBnesia., Glucina, Yltria, Zir- coma, Thoria, Oxides of Lan- thanum and Silver. Tantalic, Niobic, Tellurous Acid;

Titanic, Tungatic, Molybdic' Acids; Oxides of Zinc, Cad- mium, Lead, Bismurh, and Antimony;

b. — Yellow Beads.

Titanic, TunCic, and Mo- 1 When hjglily saturated ; lybdic Acids; Onides of Zinc ton cooling, colorless, and and Cadmium; J cloudy by flaming.

Oxides of Lead, Bismuth, When highly saturated; and Antimony ; J on cooling, colorless.

Sesquioxides of Cerium, 1 When feebly saturated ; on Iron, and Uraniuri ; / cooling, Colorless.

Sesquioxide of Chromium, when fully saturated; when cold, yellowish -green.

Vanadic Acid; when cold, greenish-yellow.

c. — Red to Brown Beads.

Sesquioxide of Didymium, rose-red; same when cold.

Sesquioxide of Cerium; on cooling, yellow; enamel-like by flaming.

Sesquioxide of Iron; on cooling, yellow.

Sesquioxide of Uranium ; on cooling, yellow ; enamel- yellow by flaming.

Seiquioxide of Chromium ; on cooling, yellowish-green.

Sesqiiioxide of Iron, containing Manganese; on cooling.

Protoxide of Nickel, reddish-brown to brown; violet while hot,

Sesquioide of Manganese, violet-red; violet while hot. Protoxide of Nickel, containing Cobalt ; violet while hot.

.,t.db,

Arrangement Oe Metallic Oxides. 289

TABLE III.— Coatinued.

With Borax in the Reducing Flame

Hot Cold.

a. — Colorless Beads. I, Alumina, Binoxide of Tin.

Zirconia I higlily saturated l)e-

a, Stroi

ia, Gluciiia,Ytti

Thoria ; Oxides of Lanthanum f ''"'y '5' and Cerium, TantaJic Acid i J fl™'"B-

SesquioKide of Manganese and Oxide of Indinm ; some- times Hie Manganese glass, on cooling, pale rose-eolored.

Niobic and Hyponiobic Acids ; when feebly saturated.

Onides of Silver, Zinc, Cad- 1 Witli strong blowing ; mium, lad, Bismnlh, Anti- [with feeble blowing, mony. Nickel, Telluroua Acid; J gray. ( Oxide of Copper] when highly Eaturated, on cooling, opaque and red.

b. — Yellow to Brown Beads.

enamel-blue by

Tungstic Acid, yellow to dark-yellow ; when eo brownish,

Molybdic Acid, brown to opaque. If the bead is i tened black binoxide of Molybdenum may be noticed.

Vanadic Add, brownish; green when Cold,

Protoxide of Cab

.,t.db,

290 ARRANGEMENT OF METALLIC OXIDES. TABLE ni. — Continued.

With Borax in the Oxidizing Flame produce:

d. — Violet Beads {amethyst-colored).

f Protoxide of Nickel ; on cooling, led dish brown to brown, Sesquioxide of Manganese ; on cooling, violet-red. Proloxide of Nickel, containing Collt; on cooling, brownish. Witt excess of Cobalt, amethyst color when cold. Protoxide of Cobalt containing Manganese; also when

e. — Blue Beads. Hot, Protoxide of Cobalt; retains its color on cooling.

f. j Oxide of Copper, when highly saturated, greenish-blue;

green whiie hot.

y. — Green Beads.

Oxide of Copper; when cold, bli

Sesqui oxide of Iron, ct taining Cobalt or Copper.

Oxide of Copper, containi Iron or Nickel.

On cooling, the color changes, according to Ihe proportion in which the various oxides are present, to light-green, blue, or yellow, im, yellowish-green ; yellow to

.,t.db,

Arrangement Of Metallic Oxides. 29!

TABLE ni. — Continued.

With Borax in the Reducing Flame

d. — Green Beads. Sesquioxide of Iron, yellowish- green ; especially when Hot cold.

AND - Sesquioxide of Uranium, yellowish-greeTi; when highly Cold, saturated becomes black by flaming,

SeiquioKide of Chromium, light to dark emerald-green. Hot. Vanadic Add, chrome -green ; brownish while hot.

g, — Gray and Cloudy £eads.

Jmium, Lead, , Anti- y

1 mony, Nickel, lellurous Acid [)

L Niobic and Iljpoiiiobic Acids; when higlily Siilurated,

f.Red Beads.

Oxide of Copper, opaque, when highly s; less while hot. Sesquioxide of Didymium, rose-rad.

o.led by

292 ARRANGEMENT OF METALLIC OXIDES. TABLE III. — Continued.

With Salt of Phosphorus in Oxidizing Flame

Produce ;

a. — Colorless Beads.

Silicic Acid; soluble only in niinule quanti.

Alumina, Binoxide of Tin; soluble with difficulty.

Baryta, Strontia, Linae, Mag- "l nesia, Ghidna, Yttria, Zirco- I nia, Thoria. Oxide of LanEha- ( num. Telluroas Acid ; J

Tantalic, Niobic, Titanic, ] Tungslic Acids; Oxides of I Zinc, Cadmium, Indium, Lead, j" Antimony, and Bismuth ;

o highly s;

b. — Yellow Beads. Tantalic, Niobic, Hyponio-" bic, Titanic, Tungslic Acids; Oxides of Zinc, Cadmium, In- dium, Lead, Antimony, and Bismuth ; J

Oxide of Silver, yellowisli; when cold, opalescent.

"1 When feebly saturated ; on Sesquioxide of Iron; I cooling, colorless. If high-

Sesquioxide of Cerium; f ly saturated, red while hot,

J yellow when cold. Sesquioxide of Uranium; when cold, yellowish-green, Vanadic Acid, deep-yellow; wheiicold.of a lighter shade. Protoxide of Nickel; while hot, reddish.

-Red Beads. Sesquioxide of Iron ; When highly

Sesquioxide of Cerium; J when cold, yellow,

Sesquioxide of Didymium, rose-colored when highly saturated.

Protoxide of Nickel, reddish ; when cold, yellow. Sesquioxide of Chromium, reddish; when cold, emerald-

o.led by

ARRANGEMENT OF METALLIC OXIDES. 293 TABLE III. — Continued.

With Salt of Phosphorus iN Reducing Flame

a. — Colorless Beads.

Silica, but slightly soluLle.

Alumina, Binoxide of Tin, soluble with difficully.

Baryta, Sfonda, Lime, Mag- 1 saturated be-

aesia, Glucina, Vttna, Zircoma, t, a

Thoria. Oxide of Whanin;r'""= °P'1'' ''5' """"S"

Sesquioxides of Didymium. Cerium, Manaanese.

Oxides of .Silver, Zinc, Cad- [nium. Lead, Bismuth;

Tantalic Acid; Oxides of Silver, Cadmium, Zinc, Indi- imi, Bismuth( Lead, and Anti- mony; TellufouB Acid;

Protoxide of Nickel, on Charcoal ;

b. — Yellow to Red Beads. Sesquioxide of Iroilj on cooling, greenish, then reddish. Titanic Acid, yellow; on cooling, violet. Vanadic Acid, brownish; when cold, emerald-green. TifanicAcidcontainilielron; 1 ir n 1. u 1.1 j

Tungstio '--' — ,!i„:„Z [Yellow; whencold,blood-

?il Yellow IV '".

Niobic Acid containing Ir

cold,

£. — Violet {amethyst) Beads.

rated ; while hot, of a pale

f Niobic Add, when highly Cold. J dirty-blue color.

t Titanic Acid; yellow while hot.

.,t.db,

294 Arrangement Of Metallic Oxides.

TABLE m. — Continued.

With Salt of Phosphorus in Oxidizing Flame

Produce :

d.— Violet (amethyst) Beads.

f Sesquioxide of Manganese, brownish-violet ; on cooling, Hot. -j pale reddish-violet.

( Oxide of Didymium; when cold, of a lighler shade.

e. — Slue Beads. Hot. Protoxide of Cobalt; when cold, of the Si

Cold. Oxide of Copper ; gteen while hot.

f, — Green Beads.

Sesquioxide of Iron, (

1 On cooling, the color changes, ording to the proportion

Ox.de of Copper, contain- f light-green,

mglronorNictel; J blue, or yellow.

Oxide of Copper; when cold, blue or greenish-blue if highly saturated.

Molybdic Acid, yellowish green ; when cold, of a lighter

Sesquioxide of Uranium, yellowish-green; while hot, ioxide of Chromium, emerald-green ; while hot,

,dlo.

.,t.db,

Index.

ACANTHITE, 122. Acicular bismuth, 157. Acids, volatile, testa for, 29.

Actinolite, 147? '85,

Adaii

Aeschynite, 160, 203.

Agalmatolite, 189.

Aikinite, 157.

AUbandite, 156, 1 60, 1 76.

Albite, 185.

Algodonile, 97, 151.

Alkalies, behavior of, before dn

blow-pipe, 2G2-267. AUanite, 1S9, 169. Allochroile, 171. AUoclasite, 15a. Allophane, 188. Almandine, 147, 171. Altaite, 154. Alainian, 189. Alumina, 45, 264. Alumiiiite, 187, 18S. Alunife, 187, 188. Alunogeti, 175, 187. Amalgam, 116, 15S. Amalgams, tests for, 31, 33, 69, Amber, 130. Amblygonile, 176. Amethyst, 204.

Amianthus, 185-

lonia, tests for, 30, 48, 262.

" salts of, test for, 30.

lonia alum, 188. Amphibole, 184. Aiialcile, 177. a I cite, 179- alysis, spectrum, 252. Andalusite, 190. \iidradite, 170. Anglesite, llo, 163. Anhydrite, 174.

Anhydrous silicate of zinc, 127. Ankerile, 193. Aiinabeiite, 120, 166. l.northite, 181. Anlhophyllite, 202. Anthracite, 128. Antigorite, 199.

monial copper, 156.

Antimonous acid, tests for, 268, Antimony, metallic, tests for, 33, " test for, when in com-

bination, 48, " oxide of, test for, 30.

bin ation, test for, 49, ores of, 86.

o.led by

30O Ind

Ex.

Antimony, sulphide of, 250,

Arsenides, to delect nickel In, 70.

" sulphides of, test for,

Arseniosiderite, 167.

Arsenolite, S9, 161.

" when in

Arsenopyrite, 105.

combination, test for,

Arsenous oxide, tests for, 31, 51

26S.

Antimony compounds, 236,

Asbestos, 185.

Anlosonite, 174.

Asbolite, 94, 195.

Apatite, S6, 176, 195.

Asphaltum, 130.

Astrophyllite, 1 70.

Apparatus, list of, 17, 20, 21.

Atacamite, 97, 165.

Atlasite, 165.

Arfvedsonite, 170.

Augite, 1S4.

Aientiferous sulphide of copper.

Auiichalcite, 165.

Autunite, 176.

Argentite, 122, 151.

Axinite, 184.

Argillite, 202.

Azurite, 99, 165.

Arquerife, 117, 158.

Atkansite, 203,

nABINGTONITE, 171.

-D Barium, salts of, test for, 39.

Arksutite, 174.

Arsenic, metallic, tests for, 31, 33,

Barium, spectrum of, 256.

Barite, 174-

lest for in arsenites and

Barsowite, 179-

aisenates, 52.

Baryta, 39.

ores of, 88.

" tests for, 264.

" sulphide of, 250.

Barytocalciie, 193.

" sulphides of, test for, 31.

Base of the flame, 217.

when in

Bayldonite, 164.

combination, test foe,

Beauiite, 202.

5°-

Beramite, 107,

Arsenic compounds, 236.

Beraunite, 16S.

Arsenical Copper, 97.

Berlinite, 188,

" pyrites, 153-

Berlhierite, 87, 156.

Acsenidea, metallic, tests for, 31,

Beryl, 205.

Berzelianite, 153,

" presence of cobalt in,

B;uuite,97,i5i.

" todetect ironin, 65.

Biolile, 1S6, 200.

.,t.db,

Index. 301

Bisniite, 91.

Brewslerite, 180.

Bismuth, meUlIic, tests for, iz<

Brittle silver ore, 123.

35. 43, z6S.

Brochantite, 165.

ere. of, 89.

Brogniardite, 156.

" test for, when in com-

Bromic silver, 121.

bination, 52,

Bromide of copper, tests for, 40.

Bromine, test for, 55.

Bismuth oclire, 91.

Biomyrite, 121.

Bismullimite, 90, 158.

Bronzite, 147.

Bismutite, 90, 172-

Brookite, 160, 203.

Brown coal, 129.

Brown hematite, 103.

Bituminous coal, IZ9.

Brucite, 191.

Black manganese, 114.

Brushite, 176.

Blende, 126, 160, 194,

Bunsen burners, 19.

Blowpipe lamp, l8.

" lamp, 210, 217.

Blue flames, 213. 214.

Bunsen's flame reactions, 216.

Blue iron earth, I07.

Blue makchite, gg.

pACOXENITE, 168.

Cadmium, metallic, tests for

Boitontte, soo.

" alloys of, test for

Bone-ash, 23.

Boraeic add, aa reagent. 22.

oxide of, lest for

" tests for, 40, 54.

Boracite, 173.

Borax, 173.

Csesia, test for, 262.

" as reagent, 22.

Csesium, spectrum of, 257.

Borax bead, 241, 242.

Calamine, 127, 1S8, 191.

Border colors, 213.

Calcite, 192,

Borickite, 16S.

Calcium, salts of, test for, 39,

Bornite, 95, 157.

" spectrum of, 2j6.

Botryogen, r67-

Calomel, 117, 161.

Cancrinite, 174, 179.

Boumonite, 108, 155.

Capillary pyrites, II9.

Braunite, 115, 159.

Carbonate of soda, as reagent, 21

Breithauptite, 156.

" lestsfor, in com-

Breunnerile, 192, 193.

bination, 42.

.,t.db,

303 Index.

Carbonate of zinc, 1 26,

Carbonic acid, test for, 30.

or, 56.

Carpholite, 182.

de of, testa for, 270.

Cassiterite, 124, 191, oj. 4-

of, 91.

Catapleiite, 180.

m mpounds, 247.

Celadoiiite, 171.

9

Celestite, 174-

, 196.

Cetargyrite, 121, 162.

Cerile. 196.

Cerium, oxide of, test for, 270.

Cerolite, 198, 202.

56, 161.

Cetusaite, 110, 163.

Cervanlite, 193.

s'

Chabaiite, 180.

Chalcanthite, 99, 165.

Chalcedony, 204.

d f, tests for, 270.

Oialcocite, 96, 157.

teats for, in combination,

Chalcodite, 169.

44,58.

Chalcophyllite, 164.

Cobalt bloom, 93.

Chalcopyrite, 95, 157.

"

pyrites, 92.

Chalcostibile, 156.

Cobalt

ompounds, 241.

Charcoal, as support, 19.

Cobalti

no, 92.

" reduction on, 226.

Cobaltite, 92, 152.

Chenevixile, 1 64.

CoUyri

e, 188.

Childrenite, 195, 204.

Colored flames, 210.

Chiollte, 174.

Columbile, 160.

Chiviatite, 91, 158.

Conichalcite, 164.

Coppe

oxide of, as reagent, 23.

Chlorine, test for, 56.

" " testsfor,39,272

Chlorite, 199.

"

ores of, 94-

CTiloritold, 201.

'1

salts of, tests for, 40.

Chloro-bromlde of silver, 12I.

"

tests for, when in com

Chloropal, 197.

bination, 59, 60.

Chodneffite, 174.

Coppe

compounds, 244.

Chondrarsenite, 175,

glance, 96.

nickel, 117,

Chonictite, 179.

pyrites, 95.

Chromic iron, 91.

"

vitriol, 99.

.,t.db,

Copperas, 1 06. Coquimhite, 167. Core colors, 213. Corneous lead, 109. Corundum, 191. Coiyiiite. 153. Cotunnite, 161. Covellite. 165. Crednerite, 159. Crocidolite, 170. Ctocoite, 112, 162. Cronstedile, 169. Crookesite, 133. Cryolite, 174. Cryophyllite, 181. Cubaiiite, 157. Cuprite, 98, 158, 165. Cuproplvunbite, 157. Cyanite, 19a. Cyanogen, test for, 30.

DANALITE, 177. Danburite, 182. Dark cone, 217. Dark-red silver ore, 122 Datolile, 176. Dechenite, 162, Descloizite, 16+. Determiiialion of compel

Deweylite, 181. Diadochite, i58. Diallage, 184. Diallogite, 193. Diaspore, 187. Didymium, 272. Dioptasei 196. Discrasite, 120, 155.

nite, 190. Dolomite, 192. Domeykitc, 97, 151. Dufrenite, 16S. Dufrenoysite, 109, 151. Dysluiie, 206.

EARTHS, beliavior of, before the blow-pipe, 262, Earthy cobalt, 94. Edelforsite, 186. Edingtonite, 176. Ehlite, 165. Ekmannite, 169. Elastic bitumen, 130.

Elati Elemi

, 130-

s, volatile, table of, 232,

behavior of the, 220. tlons of the, 234. 162,

.mhoUtt

Imerald, 1B6, Emerald nickel, 119. Emission of light, 223. Enargite, 97, 151. Enstatite, 202. Epidote, 186. Epsom Ite, 172.

Ery III rite, 93. Euchroite, 164. Euclase, 1S6, 205. Eudialyte, 178. Enlytite, 172, Enphyllite, 183, Euxenife, 203,

.,t.db,

Index.

a closed glass

Fusibility, scale of, 147

tube, 2g.

test of, 29S.

an open glass

lube, 32.

pADOLINITE, 199. VJ Gahnite, 206.

charcoal, 34.

the pincers, 37.

Galenite, loS, 156.

ith borax and s: "

of phosphori

Gosl mp Bunsen's, 217

Gay Lu e l 3.

Ih carbonate

Ceak uhe 174,

bait, 44.

FAYALITE, 159. 169. Felsobanyite, 187. Ferberite, 171, Fibrolite, 190. Fibi-oferrile, 167. Films upon porcelain, 228.

" on test-tubes, 231. Fischerite, 188. Flame colors, 213.

" base of the, 217.

" lower oxidizing, 219.

" upper oxidizing, 219.

" lower reducing, 219,

" upper reducing, 219.

" reactions, Bunsen'a, zi Flint, 204. Fluocerite, 196, Fluorine, tests for, 61. Fluorite, 174- Fluor-apar, as reagent, 22. Forsterite, 200. Fossil fuel, 128. Franklinite, Il5, 159, 160. Freieslebenitei56.

Glass tubes for

Glauberile, 174.

Glaucodot, 152,

Glucina, tests for, 266.

Gold, test for, when in combina-

" oxide of, tests for, 272. Gold compounds, 243. Goslarite, 175, igt. Gothite, 194. Graphic lellurium, loi. Graphite, 128, 160. Gray antimony, 86, 147, Gray copper, 96. Gray ore of manganese, II4. Gravity, specific, 296. Green flames, how produced, 39,

Greenockitf

194,

o.led by

Indium

GrunauiK Gypsum,

HALLOYSITE, i8S. Hardness, scale of, 85. Harmotome, 1S4. Hauerite, 156. Hausinannite. 114, 159. Hauynile, 177. Hayesine, 173. Hedenbergite, 184. Hedyphane, i6z. Helvite, 177.

Hematite, 103, 158, 160, 169, 194 Hessite, 154- High temperatures behavior of tin

Hotublende 170 185. Horn quicWlvar 117,

Horn stone 204 llovilite iS Huteiulile 167 Hyalophtme 185 Hj droboracite 1 7 S Hydrodolo nite 191 Hydrofluoric acid js reagent, 3t flydromagnesite 192. Hydrotaleite 194 Hydioussil cite of zinc, 127. Ilydioiiiute 191 Hypersthene 203 Hypostilbite, 180 TLVAITE, 169. I- Indium, speeirum of, 357. Indium, tests for, 35. 26*

ipouiiils, 240. organic compounds, determina- tion of, 131.

Iodic silver, lz2.

Iodide films, 229, 235, Z36, 237, 238, 239, 240.

Iodine, tests for, 30, 63.

lodyrite, 122, 1 62.

lolite, i!

Iridiu

" oxide of, tests for, 272. Iridium compounds, 243. Iridosmine, 102, 160. Iron, metallic, as reagent, 23. " tests for, when in combina- tion, 64, 65.

sulphides, 65.

ores of, 102.

" oxide of, tests for, 274.

" " change by heat, 33. Iron compounds, 240, Iron garnet, I47. Iron pyrites, 104.

JALPAITE, 122, Jamesonite, 109, 155. Jarosite, 1 67. JoUyte, 169, 179. Jolly's Spring Balance, 296.

KAINITE, 173. Kalioite, I72. Kaolinite, lS(|. Keilhauile, 185.

Kern

:, 87, 16!,

Klipsteinite, 159, 179. Kcemmererite, 198. Kreittonite, 206.

.,t.db,

3o6 /.

LABRADORITE. iSi. Lanaritite, 163. Lancasterite, 192. Langite, 165.

Lanthanum, oxide of, test for, 27 Lapis lazuli, 177. Laumontite, 177. Lavendulan, 93. LazuUte, 189. Lead, metallic, as reagent, 23.

" test for .when in combinatio 66,67.

" oxide of, test for, 274.

" phosphates of, test for, 68. Lead compounds, 239. LeadviKiol, no. Leadhillite, no, 163. Lehri>achiee, 153. Lepidolite, 171, 183. Lepidomelane, 170, 171. l-euchlenbergite, 201. Leucite, 191, 300. Leucophanite, 183. Libethenite, 165. Lievcite. 159. Light, emission of, 223, Light-red silver oie, 123. i,ime, tost for, 264. time-cbrqme garnet, 205. Limoite, 103, 194, Linarite, 163. Liniiasite, 93, 157. Liroconite, 164. Lithia, tests for, g, 262.

" " " ill silicates, 68.

Lithium, reaction of, 255.

LunD

MAGNESIA, test for, 264. Magne!ite, 192. Magnetic iron oie, 104. Magnetic pyrites, 104, Magnetite, 104, 15S, 160. MaUchite, 98, 165. Malacolite, 184.

Manganese compounds, 248. Manganese garnet, 182. Manganite, 159. Mantle colors, 213. Marcasite, 104, 157. Margarite, 1S3, 201, Margarodite, 201.

natite, I94.

Tiolite, 198.

:agnite, 161. Massicot, 107. Matlochite, 163.

tests for, 31,33. of, test for, 30.

xide of, tests for, 276.

H.,t.db,

c r) salts of t

Me cary compound , 23S. Mes I le 193 Metillic films 2z8 o-ides 288-

nalgams, 6g.

Milleiite Mimetilc Miargynte

'55

Mine als 147 148 IS". l6l'

ox J red list of, 207-209. Minium loS 162 Mirainlile 172 Mi'ipcltel 105 Molybdeni Molybd

Molyl denum Molybdite 17

impounds, 245.

Mii

e iQS

Monrolite 190 Monticellite 199 Mordenite 180 Morenosite 1 67 Mosindnte 180 Muscovite 183 186, 190, ; Myelin 189 Mysoii 1 161;

in, 172.

lamiite, 153. Neolite, 199. Nephelite, 17S, 185. NeiJhrite, 185.

Niccolite, 117, 152. Nickel, nitrate of, as reagent, 23. test for, when in combina'

1,70.

!S of, 1

'7-

oside of, tests for, 278, Nickel compounds, Z41. Nickel glance, 118- Nicltel green, 120. Nickeliferous gray antimony, 118. Niobic acid, tests for, 278. Niobium compounds, 247. Nitrate of cobalt, as reagent, 2S. Nitre

Nitric i

s for, 70, 2

NAGVAGITE, 154. Native antimony, 155. Native arsenic, 88. 151. Hsmulh, 89, 158. " copper, 94, 150. " gold, 101, 150.

Octahedrite, 2( Ceilacherite, 2 Okenite, 177. Oligoclase, 181 Olivenite, 100.

Ho.led by

opal, 204.

Ores, cliaraeteristies

Ores of antimony, S6,

" bismuth, 89.

" cliroinium, 91

" cobalt, 92.

" copper, 94.

" iridium, loi.

" lead, 107.

Orpimeiit, 89, 161. Orchoclase, S6, 147, 185, 204. Osmic acid, test for, 31. Osmium, oxide of, lesls for, 280. Osmium compounds, 243. Osmium-indium, I02. Guvarovite, 205. Oxalate of nicliel, as reagent, 23, Oxidation of substances, 225. Oxide films, 229, 235, 236, 237,

239, 240. Oxides, metallic, iable of, 268-287. Oxidized minerals, list of. 207-

Palladinm compounds, 242, Farisite, 194. Pcarlstone. 186. Peetolite, 178, 179, Peganile, 188. Pciicatite, 192. Penniiiitc, 201. Pentlandite, 157. Percylite, 165. Parofskite, 160, Petalite, 183. Pettkoite, 167. Pharmacolite, 174. Phenacite, 205.

Phil Plilogopite, 2

r, 29.

Oxygen, Ee

PACHNOLITE, 174. Palagouite, 169. Palladium, oxide of, tests for, 280.

. '77- , '187.

Phosphor

Pliolet ., , Phosgenite, 109, 163. Phosphate of copper, 99. Phosphate of lead, Jii.

acid, tests for, 40, 71. " "when in combi-

Phosphorus, salt of, as reagent, 22.

Phosphorus compounds, 249. Bcrophyll, 198. Picrosmine, 198.

Piedmontite, 182.

Pissopha

nte, 187.

Pitchsto

Pitticito

!66.

Plagion

e, 109, iS5.

PlalinuiT

compounds, 24

"

as support, ig.

.,t.db,

Platinum - pointed pinci nation in the, 37.

e, IS9-

Plumljago, 128. Plumbic ochre, 107, Pliimbo-gummite, 112, 18S. Polybasite, 124. Polycrase, 160, 196. Polyhalite, 174. Porcelain, films upon, 228. Potassa, tests for, 38, 72, 262, " bisulpljate of, as leagent,

Potassium, spectrum of, 255, Predazzite, 192. Prehnite, 180. Prism, plate glass. 212- Prochlorite, 201.

Pseudomalachite, 99, 165. Psilomelane, 115, 159. Pumice, 186. Purple copper, 95. Pyrargyrile, I32, 1 62. Pycochlore, 203. Pyrochroile, 192. Pyrolusite, 114, 159. PyroraorphiCe, iii, 162. Pyrope, 186. Pyrophyllite, 189,201. Pyrosclerite, 179. P;rosma]ile, 169. Pyroxene, 1 84. Pyrrhotite, 104, 1 57.

riUARTZ, 86, 191.

RAMMELSBERGITE, 153, Reactions of llxe element Reactions, special, 47, 234, Reagents, list of, 21, 24. Realgar, 88, i5i. Red antimony, 87. " copper, 98.

Red flames, 39, 216. Reduction of substances, 225. in glass tubes, 225. " on splinters of cliarcoal, 226,237,240,241. Reduction film, 234, 235, 236, Z39. Rerolngtonite, 94. Rhodium compounds, 243. Rhodium, oxide of, tests for, 280. Rhodochrote, 115. Rhodonite, 159, 171, 1S2. Ripidolite, 189, 199, 201. Rock-crystal, 204. Rcemcrite, 167. Roselite, 93. Rubidia, tests for. Rubidium, spectra Ruthenium, oxide of, te Rutile, 160, 203, 204.

n of, 257.

Salt ofphospho: Salts of ammoni Samarskite, 158 Samoile, 188. Sassolite, 175.

,, test for, 30.

.,t.db,

310 Index..

S k o fo 1 1 y 47 150.

Soda, te

sts for, 38, 262.

1 di So

" c

rbonate of, tost for, 42,

S heel e iS 83 03.

trate of, as reagent, 22.

S hill p 98

Soda ni

re, 172.

&h lorn 8

Sodalite

Sc le te 177

Sodium

spectrum of, 255-

SCO d e 07

Solution of cobalt, test for, 44.

S lb 6

Soidavalite, 181, 184.

Selendes tests fo 4

Spathic

roil, 106.

Sel un fo 3 34,36.40.

Special

eaetions. 47, 234.

Spe fi

rr ty minerals, 296

Se m,™ J s

Spc

, 210, 252.

& 1 nque k Ibe bl 53

Senann nti 6

Spesa

Sep 1 e 8 97

Sph n

Serpen n 70 98

Sph

6 91,

Seybertite, 1S7, 190, 199 00

Sph

S

Siderite, 106, 167, 193.

Sp n

Sideroschisolite, 169.

Sp

Silica, tests for, 74, 266.

Spod m

e, 83

Silica compounds, 247.

S ni

Silicates, tests for, 73, 74,

S

" reaction of, 57

to detect lithia n 68

Sta

3 SSv

Silicic acid, test for, 42.

S nb

gi 57

Sillimanite, I90,

S n

Silver, metallic, test for, , 6

b

6, 55

" chloride of, as reagent, 23.

Stilbite,

" oresof, I20.

Stilpnon

elane, 169, 171.

" oxide of, tests for, 280,-

Stoliite

" test for, when in combina.

Strom eyerite, 124, 157.

tion, 75.

Strontia

tests for, 264.

Silver compounds, 244,

Stcontia

ite, t73, 192. 193-

Silver glance, 122,156.

Stronliu

m, spectrnin of, 256.

Skoiopsile, 17S.

Struvile

Skutterudite, 152.

Stylotypite, 155.

Smaltine, 92.

Succinite, 130,

Smaltite, 92, 152.

Sulph-a

seiiides, tests for, 51.

Smitbsonitc, 126, 191.

Sulphid

films, 231,235,236,237

238, 239, 24". 241-

.,t.db,

I Mb Ex. 311

Sulphides, tests for, 31,

Tellurous acid, tests for, 31, 40,

" to detect cobalt in, 58.

copper in, 60.

Temperatures, high, behavior of

iron in, 65.

the elements at, 220.

lead 111, 67.

Tennantite, 97, i;i.

iiicltel in, 70.

Tephroite, 182.

Sulphides of antimony, tests for, 31.

Test-paper, 23.

" arsenic, tests for, 31.

Test tubes, films on, 231.

Sulphur.testsfor, 31,33, 77.

Teirahedrile, 96, 155.

" to detect tlie presence of.

Tetradymile, 89, 154.

m lulphides, 77

Thilhum compounds, 238.

Thalliom, spectrum of, 257-

Sulphuric acid, tests for, 78, 215

Thenardite, 172.

SuiphuiLtled hydrogen, test for, 29

Thermophylhte, 183.

Sulphuious acid, tests for, 29, jS

Thomsenohle, 174.

Supports 19

Thona, te=ls for, 266.

Susanmte, i6j

Thorite, 196

Svanbeigite, 189

Tiemanrnte, 153-

Sylvanite 101, 154

Tm, rngtallic, reagent, 23,

Sylviie, 173

tests for, 36, 80.

Syalematii. method for the deter

" oiesof, 124.

mi nation of )nor£,anic warn

" o\ides of, tests for, 282.

pounds, 131.

" to detect copper in, 80, 81.

Tin compounds, 245.

'-pACHYLYTE, 181. 1 Tagiliie, 165.

Tin ore, 1 24.

Tin pyrites, 125.

Tak, 86, 200,

Titanic acid, tests for, 42, 81, 282

Taliingite, 165.

Titaniferous iron, joj, 169.

Tantalic acid, teats for, 280.

Titanite, 1S2, 185,

Tantalite, 160.

Titanium, tests for, 81.

Tantalum compouiKfe, 247.

Titanium compounds, 246,

Topaz, 86, 190, 205.

Telluric bismuth, 89.

Torbernite, 166, 176,

Tellurides, test for, 33.

Tourmaline, 170, 184, 199,

Tellurium.teslsfor, 31,33, 36

Tremolile, 184,

" " when in com-

Triphylite, 168.

bination, 79.

Triplite, 167,

" ores of, 154.

Trolleite, 187.

Tellurium compounds, 234-

Trona, .73.

.,t.db,

312 In.

Tschermigile, i;5, i8;. Tungsten compounds, 246. Tungstic acids, tests for, 42, 284. Tungstite, 203. Turgite, 194. Tarquois, 195. Tyrollte, 100, 164.

TTLEXITE, 173. U Ullmannite, 118, 153, 156. Uraninite, 160, 195. Uranium, test for, in presence of

iron, 82. Uranium, oxide of, tests for, 284. Uranium compounds, 248.

VALENTINITE, i6i. Vanadic acid, tests for, 284. Vanadinite, 163, Vanadium compounds, 248. Vauqnelinite, 113, 163. Vesuvianite, 186. Titrifiedboracicacid,asreagent,2; Vivianite, 107, 168. Voigtite, 169. Volhorthite, l65. Volgerite, 193.

ITrAD,,.5,.9S. VV Wagneritc, 176. Watwicltite, 202. Water of crystal lisation and hy- dration, tests for, 29, Wavellite, 188.

ite, 127, 1S9, 191.

fe,iS4.

Wittichite, 157. Woehlerita, iSl. Woichonsltoite, 197, 202, Wolframite, 158, 171. WoUastonite, 178, 186. W6rtliite, 190. Wulfenite, 113, 163.

Xanthoconite, 162.

Xonaltite. 179, 196. Xylotile, 170, 197.

1, 214. !

Yttria, tests for, 266, Yttrocerite, 193, 196. Yltro-tanlalite, 160.

Zinc, metallic, test for, 36. ores of, 125. oxide of, change by heal, 3.

test for, when in combina- i, 84.

Wer

--, 181.

While arsenic, 89. White iron pyrites, I White lead ore, no. Whilneyile, 97, 151.

Zinc.

inds, i

15. 19S- Ziiikenitc, 109, 155. Zippeite, 195. Zircon, 205. Zircoiiia, tests for, 26( Zoiiite, 186. Zone of fusion, 219, Zorgite, 154. Zwieselite, 168.

o.led by