Mine-Surveying
This paper is in the public domain in USA. Metadata comes from the CrossRef API, see full record in the source URL below.
Public-domain full text preserved in the Mountain Man Mining Library. Original source: archive.org.
August 2, 1888]
Na Ture
county. There is no evidence that these " chiefs " owned the land they were selling, nor that they were made aware that they were parting for ever with their most cherished possessions, of which Mr. Strachan attempted to claim ownership (Her Majesty's edict notwithstanding) in right of exploration and purchase. While in Macluer Inlet, the author resided among a people who spoke to some extent the Malay language. The quotations with which we are favoured in his book, not to mention his own admission of the fact, show clearly how imperfect his knowledge of that language (as of the true language of the region) is. Yet from a conversation he overhears, half of which only, he admits, he understood, he accuses certain chiefs of Macluer Inlet of slave-hunting, and in the most high-handed and unauthorized manner, carries them off prisoners to Gessir, to give them in charge to the Dutch authorities, yet does not do so (owing to stress of weather), which under the grave circumstances he ought to have done when the weather moderated. Eventually, after severe cogitations whether he should not himself inflict punishment on them, he returns them to their homes, when he feels "much lighter of heart." Shortly after this, he sees a canoe "dodging backwards and forwards among the islands within gun shot of the ship," and is seized with a panic (as he often was), and without the flimsiest evidence of a hostile intention on the part of its occupants, he seized a " long range rifle " and fired into it; " they then began paddling rapidly, and although I fired many shots I could not round them to." Nor are these again the solitary instances of most illegal acts performed by Mr. Strachan as recorded by himself. It is doubtful, also, whether the removal of the little lad whom he brought from his country to England (and whom he appears to have treated with the greatest possible kind ness) was not an act of kidnapping. Altogether, it is perhaps not surprising that the natives, as Mr. Strachan bemoans, " cannot recognize nor appreciate the principles of honesty and honour," so exemplified.
Her Majesty's Special Commissioner comes in for a most violent and unwarrantable attack. No one who reads Mr. Strachan's own admissions will wonder that his explorations were not regarded by the authorities with all the favour he could desire. If Mr. Douglas had had the facts here recorded before him, he must, we fear, instead of renewing the author's permit, have excluded him from again approaching the island. The Commissioners administering the Government in New Guinea have had experience enough of the woes that flow not to the natives themselves only, but to unsuspecting Europeans who have the misfortune to follow behind (and have paid, too often, the penalty of the overacts of) such explorers as "Captain" John Strachan.
Mine-S Ur Ve Ying.
A Treatise on Mine-Surveying. By Bennett H. Brough, F.G.S., F.I.C., 8vo., pp. 282 with 101 woodcuts, two appendices and index. (London: Charles Griffin and Co., 1888.)
lyr R. BROUGH, who for many years has been giving instruction in surveying at the Royal School of Mines, has placed the mining world under a debt of
gratitude to him by the issue of his compact manual It is the. kind of book which has long been wanted, and often asked for, not only by mining students, but also by mine-agents desirous of obtaining more knowledge con cerning a material branch of their profession.
The book is divided into nineteen chapters. In the first the author dwells upon the importance of mine surveying and certainly does not exaggerate it. Instances could be multiplied showing the danger to life and the loss of valuable mineral from the want of accurate plans. A blot in British legislation does not escape the author's notice, and he very properly regrets that the agents of ordinary ore-mines are not required to qualify themselves by examination in the same way as their brethren at collieries. Considering that the tin miners of Cornwall have a rather higher death-rate from accidents than colliers, and a very much higher death-rate from diseases induced by their occupation, it does seem strange that the test of ability imposed in one case should be entirely dispensed with in the other. When the Metalliferous Mines Regulation Act is amended we may hope to see this anomaly swept away Many agents of ore-mines would welcome the introduction of certificates of com petency, because a Government diploma would raise their status at home and constitute a valuable passport for them abroad.
Four chapters are devoted to surveying with the ordinary miner's dial, of which various forms are described ; and very useful hints are given concerning sources of error with the magnetic needle', which would not strike tyros, and some of which are probably unknown to many practised surveyors. The important question of the diurnal and secular variation of the magnetic needle is next fully dealt with, and we hope that due heed will be paid to Mr. Brough's remarks, for few ordinary diallers are aware that the needle may vary 10' from 8 a.m. to 1 p.m.
The theodolite is properly recommended for cases where great accuracy is required, and much useful infor mation is afforded upon various matters, such as plotting, calculation of areas, levelling, connection of underground and surface surveys and methods of rapid surveying with the tacheometer. Faults and subsidences are discussed at length, and careful directions are given concerning the construction and copying of mine plans. Mr. Brough insists upon neat lettering, but curiously enough omits all mention of stencil plates for this purpose.
The last chapter, dealing with the application of the magnetic needle in mining, is full of interesting matter. We have good descriptions of the Swedish and American dip-compasses, and the improved methods of Brooks, Thalen and Tiberg, for exploring for iron ore ; and the author exposes the clever devices of unscrupulous minesharks for misleading intending purchasers. Between the years 1868 and 1875 eighty-five iron mines were dis covered in the State of New Jersey solely by the magnetic needle, and in many cases where there was no visible indication of ore at the surface.
Mr. Macgeorge's ingenious appliances for ascertaining the true direction taken by bore-holes, which frequently deviate very considerably from the vertical, attracted much attention at the Inventions Exhibition, where they received a gold medal. Now that Mr. Macgeorge's
© 1888 Nature Publishing Group
Na Ture
[August 2, 1888
method is described in a text-book, its advantages will become more generally known.
Mr. Brough deserves much praise for the care with w'hich he has searched European and American publica tions so as to bring his work up to date, and there is little call for censure save upon minor points which do not affect the general value of the text-book.
It is time that some one should enter a protest against two of the technical terms defined by the author, and frequently met with in the reports of mining experts, viz. "country rock " and " gangue." To say " country rock ' is tautology. The word " country " alone, as used in Cornwall, means "surrounding rock" or "enclosing rock," and, if the provincialism is to be adopted, there is no necessity to add the word " rock." The -word " gangue " is objectionable, because it has come to us through Frenchmen, who apparently did not thoroughly understand the meaning of the German word " Gang." " Matrix," " lodestuff," and " veinstuff " are better w'ords than "gangue," which might well be allowed to drop out of mining books, especially as it is rarely heard at mines.
To cite the china clay deposits of Cornwall as examples of stockworks is unfortunate, because the occurrence in them of veins bearing workable quantities of tin ore is the exception, not the rule.
In Chapter VIII. Mr. Brough says: "In 1798 Breithaupt, of Cassel, invented a mine-surveying instru ment, which he called an astrolabium." This remark is not correct, for, as the author well knows, the astrolabe was invented by the ancients. The statement should have been that H. C. W. Breithaupt was one of the first to put an astrolabe upon a stand and use it for surveying underground. According to Mr. Brough the theodolite has been employed more or less for mine surveys since 1836. This date is probably correct as far as Germany is concerned ; but as a matter of fact a mining theodolite was supplied to the Imperial Brazilian Mining Association four years earlier.
The description of Prof. Borcher's method of using magnets for ascertaining the precise line in which one should continue to work in order to connect two drivages in opposite directions which are approaching each other, is not so clear as it ought to be. Mr. Brough omits to explain, in reference to Fig. 101, that by construction the points A, B, and C are situated upon the circumference of a circle, the centre of which is E ; and the confusion is increased by the statement that the triangle A E C is " equilateral," whereas it is really only isosceles. The consequence is that the reader is very much puzzled.
How'ever, these and a few other errors can easily be corrected in a second edition, which is likely to be required before many years are past ; because, as soon as the book becomes knowm, no English-speaking mineagent or mining student will consider his technical library complete without it. C. Le Neve Foster.
Our Book Shelf.
Charles A. Gillig's Tours and Excursions in Great Britain. By Stephen F. Smart. (London: United States Exchange, .1888.)
This book is intended in the first instance for Americans, but it may also be of some service to English tourists. Taking London as a central point—" not only because it is
the most notable city of the world, but because it is the Mecca, if not the El Medina, of trans-Atlantic tourists, at least "—the author describes a series of excursions, any one of which will well repay the trouble of those who may elect to follow' his guidance. He also describes various tours in Wales and Scotland. Mr. Smart has been at pains to make himself familiar with the ground over which he undertakes to lead others, and the infor mation he presents, so far as we have been able to test it, is thoroughly trustworthy. Of course, no one who wishes to obtain a full account of any particular town or district will think of consulting this little book. But as a general sketch, it has considerable merits ; and it will doubtless help many American visitors to make the most of a brief visit to Great Britain.
Letters To The Editor.
[The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he under take to return, or to correspond with the writers of, rejected manuscripts iritended for this or any other part of Nature. No notice is taken of anonymous communications .]
The Supply of Bait for Sea-Fishermen.
One of the first questions of practical importance with which the Marine Biological Association has to deal is that of supply ing the long-line fishermen with a continuous supply of bait at a cheap rate. Great distress is often occasioned through fisher men being unable to get the necessary bait for their long lines. Mr. Robert Bayly, of Plymouth, a governor of the Marine Biological Association, has generously given a sum of A 5 00 t° be spent on investigations on the bait question, and the Council have instructed me, as Director of the Association, to consider the best means of spending this sum. I shall therefore be glad to receive any suggestions from gentlemen who may interest themselves in this question, or to consider the work of any investigator already in the field, with the view of employing a suitable person to carry out a series of observations and experiments.
Two methods appear to offer a solution to the question. Either the animals used commonly as bait, such as w'helps, mussels, and squid, may be reared artificially and kept in confinement till re quired, or some artificial bait may be invented which will lure the more valuable kinds of fish to the hook.
The former of these methods has been successfully practised in F ranee, but such is the operation of the English laws on shore fisheries that there is very little prospect of its being possible in England, unless those laws are altered.
The second method, though more apparently difficult, is the more likely to attain success. Fish are undoubtedly guided by smell and taste in the selection of their food. Some are known to be very nice about the kind of food offered to them, and will only take certain kinds of bait. The u'helk is a very favourite morsel, and has a distinct smell and taste : it may be possible to determine by analysis the essential oil or whatever it may be that gives this odour, and to imitate it sufficiently well to deceive the fish. The trade is able to imitate successfully the bouquet of wines : cannot chemistry produce an imitation of the bouquet of the whelk ? G. C. Bourne.
The Laboratory, Citadel Hill," Plymouth, July 31.
Geometric Meaning of Differential Equations.
In the Proceedings of the Royal Asiatic Society of Bengal, 1888, p. 76, Prof. Asutosh Mukhopadhyay has proposed a really excellent mode of geometric interpretation of differential equa tions in general: viz. writing the equation in form F o, the geometric meaning of the symbol F considered as a magnitude (angle, line, area, &c.), in any curve wkatajcr (wherein F is of course not zero), is, if possible, to be formed ; then the geo metric meaning of that equation obviously is that the quantity F vanishes right round every curve of the family represented. This is the most direct geometrical interpretation yet proposed.
© 1888 Nature Publishing Group