Transactions Of The American Institute Of Mining And Metallurgical Engineers Vol Lxxi

American Institute Of Mining And Metallurgical Engineers

Transactions Of The American Institute Of Mining And Metallurgical Engineers Vol Lxxi

American Institute Of Mining And Metallurgical Engineers · 1925 · Historical

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Transactions

Of The

American Institute of Mining AND Metallurgical Engineers

Containing Papers and Discussions Presented at the Meeting Held in Birmingham, Ala., October, 1924, the Meeting Held IN New York, February, 1925, and the Meeting of the Institute of Metals Dh'ision Held in Milwaukee,

Wis., October, 1924

New York, N. Y. Published By The Institute

At The Office Of The Secretary

29 WEST 39th Street

COPTBIGHTt 1925 BT THB

Amebican Institute of Mining and Metallurgical Engineers

(In00Bp0B4T1D]

Printed In The United States Of America

The Maple Press York Pa

Preface

In this volume are the papers and discussions presented at the Birmingham Meeting, October, 1924, the New York Meeting, February, 1925, and the Meeting of the Institute of Metals Division in Milwaukee, October, 1924; also the Proceedings of the Birmingham and New York Meetings.

Papers

Environmental Conditions of Deposition of Coal. By David White (With

Discussion) ... 3

Microscopical Constitution of Coal. By Reinhardt Thie.ssen (With Discussion) 35

Microstructure of Coal. By Clarence A. Seyler ... 117

Microscopical Structure of Anthracite. By Homer G. Turner (With Discussion) 127

Coal in Relation to Coke. By Edward C. Jeffrey (With Discussion) 149

Resolution of Coal by Oxidation. By W. Francis and R. Wheeler (With

Discussion) . . 165

Constitution of Coal. By F, V. Tide.swell and R. V. Wheeler (With Discussion) 176

Organic Sulfur Compounds in Coal. By J. Jolly' and R. V. Wheeler (With

Discussion) 184

Selective C'ombustion in Coal. By F. S. Sinnatt (With Discussion). . 189

Nitrogenous Constituents of Coal. By John W. Cobb (\\'ith Discussion) . . 211

Coal and Oxygen. Bj' S. W. Parr and F. B. Hobart (With Discussion) 216

Modern Views of the Chemistry of Coals of Different Ranks as Conglomerates.

By A. C. Fieldner and J. D. Davis (With Discussion) ... 227

Contact Metamorphism of Some Colorado Coals Intrusives. By J. Brian

Eby (With Discussion) 246

Progressive Regional Carbonization of Coals. By David White (With Discussion) 253

Moisture as a C'opponent of the Volatile Matter of Coal. By W, T. Thom, Jr.

(With Discussion) 282

Mascot, Tennessee, Zinc Area. By Wilbur A. Nelson 289

Ducktown, Tennessee, Copper District. By Wilbur A. Nelson 299

Notes on the Clinton Group in Alabama. By Truman H. Aldrich 304

Phosphate Deposits of Idaho and Their Relation to the World Suppl 3 By

Virgil R. D. Kirkham (With Discussion) 308

Manufacturing Problems of Cement Industry. By John J. Porter 339

Rotary Calciners for Gypsum. By Frank A. Wilder (With Discussion) . . . 347

Analysis of Performance of a Coal Jig. By H. F. Yancey and Thomas Fraser . 1079 Coal Washing Practice in Alabama. By H. S. Geismer (With Discussion) . . 1088 Byproduct Coking in Alabama. By F. W. Miller (With Discussion). . . . 1106 Belt Conveying of Coal at H. C. Frick Coke Co. Mines. By Thomas W. Dawson (With Discussion) 1112

Review of Coal-dust Investigations. By George S. Rice 1130

Economics of Rockdusting Bituminous Coal Mines. By Edward Steidle. . 1164 Value of Humidifying Methods in Explosion Prevention in Coal Mines. By

D. Harrington (With Discussion) 1185

Safeguarding Coal-mining Operations against Danger from Oil and Gas Wells.

By A. W. Hesse (With Discussion) 1204

Schedule Rating Coal Mines in Pennsylvania for Compensation Insurance

Rates. By Rush N. Hosler (With Discussion) 1226

Application of Gaussian Curve to Mining Industry. By Hugh Archbald

(With Discussion) 1236

Properties of Liquid-oxygen Explosives. By G. St. J. Perrott (With Discussion) 1248

Increasing Production of Petroleum by Increasing Diameter of Wells. By

Lester C. Uren (With Discussion) 1276

Significance of Fluid Level in Oil-well Pumping. By Lester C. Uren 1301 Determining the Constants of Oil-production Decline Curves. By Harry

M. Roeser 1315

Mathematical Determination of Production Decline Curves. By Charles S.

Larket 1322

Comparative Study of Well Logs on the Mexia T3rpe of Structure. By Frederic H. Lahse (With Discussion) 1329

vm

Biographies

David Talbot Day 1371

William A. Clark 1374

WHiLBT G, Millbr 1376

Officeks And Committees

OmCEBS AND DIBBCTOBS

Officers And Directors

For the year ending Febnuuy, 1926

Pbesident

J. V. W. REYNDERS, District 0 New Yobk, N. Y.

Past Pbesidbnts

E. P. MATHEWSON, District 0 New Yobk, N. Y.

WILLIAM KELLY, District 5 Iron Mountain, Mich.

First Vice-president

E. DbGOLYER, New York, N. Y.

Treasurer

CHARLES F. RAND, New York, N. Y.

Secretary

FREDERICK F. SHARPLESS,* New York, N. Y.

H. FOSTER BAIN,t New York, N. Y.

Assistant Secretary

PERCY E. BARBOUR, t New York, N. Y.

Vice-peesidbnts

T. T. BREWSTER ' District 6

FRANK M, SMITH, 1 District 11

E. DeGOLYER,* District 0

CHARLES W. MERRILL,*. . . . District 10

JOHN L. District 13

RALPH H. SWEETSER,* District 3

Directors

WALTER H. ALDRIDGE,! . . . District 0 GALEN H. CLEVENGER,! , . . District 1

AMBROSE N. DIEHL,* District 3

SEELEY W. MUDD,! District 10

RENO H. SALES,* District 7

R V. NORRIS.* District 2

GEORGE OTIS SMITH,* District 4

P. B. BUTLER,* District 6

BERTRAM D. QUARRIE,* . . . District 3

L. D. RICKETTS,* District 9

SYDNEY H. BAli,* District 0

J. M. CALLOW* District 0

W. H. BASSETT,* District 1

GEORGE D. BARRON,* District 0

CHARLES F. RAND,* District 0

Counsel

DOUGLAS, ARMITAGE AND McCANN, .

. . .St. Louia, Mo. . . Spokane, Wash. . New York, N. Y. San Francisco, Cal. Copper Cliff, Ont. . . Columbus, Ohio

New York, N. Y. . Boston, Mass. . .Duquesne, Pa. Los Angeles, Cal.

. . Butte, Mont. Wilkes-Barb% Pa. Washington, D. C. . . . Joplin, Mo. Cleveland, Ohio Warren, Ariz. New York, N. Y. New York, N. Y. Waterbury, Conn. New York, N. Y. New York, N. Y.

New York City

Unta Feb., 1926. UntU Feb., 1927. UntU Feb., 1928.

Elected Secretary Emeritus, July 1. Secretary, July 1.

Resigned, July 1.

Xu

PAST AND PBaSSNT 0FFICSB8

Past and Present Officers

Presidents

♦David Thomas

♦R. W. Raymond . .

♦A, L. Holley

♦Abeam S. Hewitt

♦T. Sterby Hunt

♦Ecklby B. Coxe

♦William P. Shinn

♦William Metcalf

♦Richard P. Rothwell. . .

♦Robert W. Hunt

♦Jambs C. Bayles

Robert H. Richards

♦Thomas Egleston

♦William B. Potter

tRiOHARD Pearce

♦Abram 8. Hewitt

♦John Bibkinbine

♦H. M. Howe

♦John Fritz

♦J. D. Weeks

♦E. G. Spilsbury

♦Thomas M. Drown

♦Charles Eibchhoff

♦James Douglas

E. E. Olcott

♦Albert R. Ledottx

♦Jambs Gayley

♦Robert W. Hunt

John Hays Hammond

D. W. Bbunton

♦Charles Kirchhoff

♦Jambs Gayley (Corporation)

Jambs F. Kemp (Council and Corporation)

Charles F. Rand

Benjamin B. Thayer . .

William L. Saunders . .

L. D. Ricketts

P. N. Moore

Sidney J. Jennings

♦Horace V. Winchell. . .

Herbert Hoover

♦Edwin Ludlow

Arthur S. Dwight

E. P. Mathbwson

William Kelly

. . 1872-1874

. 1878-1879

. 1884-1886

. . 1891-1892

1898 . 1899-1900 .. 1901-1902

. 1904-1905

. 1907-1908 . 1909-1910

1905-1911

. .. 1913 1914 1915 1916 1917 1918

1920 1921 1922

Secretaries

♦Martin Coryell ... 1871-1872

♦Thomas M. Drown ... 1873-1884

♦R. W. Raymond 1884-1911

♦Joseph Struthers 1911-1912

Bradley Stoughton ... 1913-1921

Frederick F. Shabpless . . ... 1921-1925

H. Foster Bain 1925——

Treasurers

♦J. Pryor Williamson . . . ♦Theodore D. Rand . . .

Frank Lyman

George C. Stone

George D. Barron — Charles F. Rand

1871-1872 1873-1902 1903-1912 1913-1918 1918-1922

Deceased, f Non-member at present.

Past And Pbebent Officebs

xm

Officers of the Institute 1871 to 1925, inclusive

P, President; PD, President of Board of Directors; V, Vice-president; VD, Viee-president of Board Directors; M, Manacer; S, Secretary jSD, Secretary of Board of Directors: S. £m, Secretary Emeritus; s, Assistant Secretary; T, Treasurer; t. Assistant Treasurer; D, Director; C, Councilor; £, Editor; e, Assistant Editor

Aombw, John L., V, *25.

Aldbidob, Waltxb H., D. *15-17, *21-25. tALBXANnaB, John S., M, *74-6, *81-3. Ashbubnbb, C. a., M, *85-7. tAsicus, Gbobob, M, *78-80. H., M, *00-2.

Bain, H. Fostbb, S, *25.

Ball, H., D, *24-25.

Babboub, P. E., s, *19-25.

Babbon, Gbobob D., D, *15-25; T, *18-22. Bassbtt, W. H., D, *22-25.

'Bxbxxmbinb, John, M, 83-5; V, *87-8; P, *91-2. Blaib, Thomas S, M, *74-6.

♦Blabb, William P., V, *71-4, *76-7. *05-6. *Blandt, John F., V, *71-3, *78-9.

♦Blow, A. A., C, *05-7. tBowiB, A. J., Jb., V. *93-4.

♦Bbamwbll, j. H., M, *89-91.

, T. T.. V. *23-25.

Bbock, Rbqinald W., D, *14-16.

IBbooks, Thos. B., M. *72.

Bbunton, D. W., V, *97-8; P, *09-10.

♦Buck, Stuabt M., M, *83-5.

, Albbbt, V, *21-23.

♦Bubdbn, Jambs A., V, *80-1.

♦Bubnham, William, M, *82-4.

Butlbb, P. B., D, *24-25.

Callow, J. M., D, *25. tCAMPBBLL, H. H., M, *93-5.

Cablton, Albbbt E., C, *11-12. tCABLTLB, W. A., D, *20-21.

Cates, Louis S., D, *19-21.

Catlin, R. M., D, *20-22. tCHAMBBBLAlN, H, S., V, *96-7.

Channino, j. Pabkb, V, *08-9.

♦Chbistt, S. B., V, *91-2, *07-8, *11-12. ♦Chubch, John A., M, *79-81, *94-6; V, *07-8. Clbvbnobb, G. H., D, *20-25.

♦Coqswbll, W. B., V, 74-5, 86-7.

CoLB, Thos. F., V, *05-6. tCooK, Edoab S., M, *84-6.

♦Cobninq, C. R., C, *08-9.

CoBSB, W. M., D, *20-22.

♦CoBTBLL, Mabtin, 8, *71-2; M, *73-5. CoTTBELL, F. G., D, *18-20. tCox, E. T., M, *77-9.

♦Cox% Ecblbt B., V, *71-4, *76-7, *84-5, *89-90; 78-9.

♦CoxB, Wm. E. C., M, *79-81, *85-7.

♦Cbockbb, G. A., M, *01-3.

Day, D. T., V, *92-8, *00-1.

DbGoltbb, E., V, *21-25. ,

DsLandbbo, C. F., V, *02.

Dbnton, Fbbdbbicb W., V, *08-9, *13-15. ♦DbSaxtllbs, a. B., M, *87-9.

Dbybbbux. W. B., M, *98-00.

Dibhl, a. N., D, *23-25.

D*Invillibb8, E. V., V, *94-5; M, *00-2.

Dobb, j. V. N., D, *18-19.

♦Douglas, Jambs, V, *97-8; P, *99-00; D, *05-13; VD, *06-11.

Dbinkbb, Hbnby S., M, *77-9; V, *18-20. ♦Dbown, 'Thomas M., M, *72; S. *73-84; V. *92-3; P, *97.

♦Dudley, Chablbs B., V, *80-81.

V 21* P *22.

fDwioHT, 'i'HBODOBB, 8, *95-05; t, *98-05; D, 06-11; C, *06-8.

Easton, Stanly A., D, *19-21.

Eavbnson, H. N., D, *17-19.

♦Eolbston, *rHOMA8, M, *71; V, *72-4, *77-8, 84-5; P, *87.

♦Eilbbs, Anton, M, *75-7; *82-4; V, *96-7. Eilbbs, Kabl, C, *09-11; V, *12-14; *16-18. ♦Ely, T. N., V, *82-3.

♦Emmons, S. F., V, '83-1, *90-1, *02-3.

Eubtis, W. E. C., V, *97-8.

Fackbnthal, B. F., Jb., M, *87-9; C, *07-9. Fabish, John B., V, *08-9.

Fbustman, L. P., V, *98-9.

Finch, John W., D, *13-15.

♦Fibmstone, Fbank, M, *73, *84-6, *89-91, V, *75-6. Fobbyth, Robbbt, M, *88-90.

Fbancis, L. W., D, *20.

♦Fbazbb, B. W., M, *74-6, *78-80.

♦Fritz, John, V, *75; P, *94.

♦Fulton, John, V, *85-. tGAUJOT, E., M, *71-2.

♦Gaylby, Jambs, M, *96-8; V, *02-3; P, *04-5- PD, *05-11; D, *05-13.

♦Glenn, William, M, *99-01.

♦Gobtz, Gbo. W., M, *92-4; V, '01.

Goodalb, C. W., M, *97-9; D, *16; V, *17-19. tGBAMMBB, F. L., M, *04; C, *05-6.

♦Gbant, j. B., V, *06-7.

Gbebnway, j. C., D, *21-23.

♦Hague, Jas. D., V, *06-7.

Hammond, J. H., V, *01-2; P. *07-8.

Habdman, j. E., V, *01-2.

♦Habtshobnb, Joseph, M, *04; C, *05-6. ♦Heinbich, Oswald J., M, *75-7.

♦Hewitt, Abbam S., M, *72-5; P, *76, *90. ♦Hofman, H. O., M, *94-6; C, *07-9.

♦Holbbook, Levi, M, *95-7.

♦Holley, A. L., V, *74; P, *75; M, *77-9.

Hollis, H. L., M, *92-4.

♦Holloway, J. F., V, *87-8, *94-5.

♦Holmes, Joseph A,, D, *114.

P *93

Humphbeys, a. C., C, *09-11.

♦Hunt, A. E., V, *88-9.

♦Hunt, Robebt W., M, *76-8; P, *83, *06; D. *13-17.

♦Hunt, T. Stbbby, M, *73-5; P, *77; V, *88-9. Ingalls, W. R., C, *07-9.

Jacklino, D. C., D, *14-16.

Janbway, John H., Jb., C, *12; D, *13-15. Jennings, Robbbt E., C, *10-12.

Jennings, Sidney J., C, *12; V, *13-17; P, *18; D, *19, *20.

♦Johnson, J. E., M, *86-8, *01.

♦Johnson, J. E., Jb., D, *17-19. tJoNEs, Clemens C., M, *02-3.

Kelly, William, C, *10-12; D, *22-23, *25; P, *24.

14; P, 12; Pd, *12.

Kennedy, J., V, *04-5.

♦Kent, Joseph C., V, *74-5.

♦Kent, William, M, *00-2.

♦, W. C., V, *83.

♦Keyes, W. Sm M, *80-2; V, *84. fKlMBAL J. P., V, *81-2.

Kibby, E. B., vD, *12; D, *13-14.

♦Kibchhoff, C., M, *87-9, *92-4; V, 96-7; P. *98. *11; D, *07-12.

Klbpbtxo, Fbanx, M, *03-4; C, *05; D, *05-6. Kunhabdt, W. B., V, *95-6.

Kunz, Gbo. F., V, *99-01.

Laist, Fbbdebick, V, *20-22.

♦Lathbop, William A., V, *11-12.

♦ Deceased, t Non-member at present.

Past And Pbesent Officebs

*, Robt. G. V, '93-4.

Aimbt R. M, *95-7; V, *93-9, 19-28.

P, 08; D, 05-16.

♦Lmu J. H.. V. *03-8.

Lboobtt. Thomas H., V, *13-15.

*Lwut. J. P.. M. *73-4.

*LHins. Jambs F.. M. *70-81; V. *86-7. *95-6. LnfDOBBH. Waldbmab. y. *13-13.

Ludlow, Edwxh. D. *16-19, *22. *23; V. *10-20, P, *21.

41.TMAM. B. a, M. '96-a Ltmam, Fbamh, M, *97-9; T, *08-12; C. *05-6; D. *08-12.

fMACDONAiiD. Cbabias. V, *82-3, *89-90. Mackintosh, J. B.. M, *91.

MaoNauohton, Jambs, V. *16-18.

Mabxlb, John, V, *08-4.

Mathbb, W. Q.. D, *21-23.

Mathbwson, £1. P., D, *13-15, *21-22, *24-25; P, *23.

*Matnabd, Qbobob W., M, *71-4, *85-6; V, *04-5 McCbbath, Andbbw S., M, *82-4.

*MoNaib. T. a, M, *71, *84.

Mbbbux, Chabuds W., D, *14-16; V, *24-25. *MBTOALFtWxLLiAM. V, *78-9; P, *81. *Mobn, Phiup W., V, *03-4.

Muod, 8. W.. V, *20-22; D, *23-25.

Munbob, H. Sm M, *81-4; V, 90-1.

Nbill, Jambs w., m, *02-4.

Nbxlson. W. Q.. M, *86-8. fNBWBBBBT, J. M, *76-8.

Nobbis, R. V., C. *08-10; V, *11-12; D. *20-25, OiiCOTT, E. £., P. *01-2.

Omott. W. J., M, *98-00; C, *11-12; D, *13. Paob, W. N.. V. *90-00.

Pabkbb, £. w., M, *02-4.

Pbabcb, Riohabo, V, *85-6; P, *89.

*Pbabsb, John B., V, *77-8.

♦, E. D.. Jb., V. *98-9. tPBTHBBiox, Imomas, M, *71-2; V, *84.

♦, Wm, H., M, *73, *89-91; V, *81-2. ♦Platt, J. C., V. *94-5.

Pobtbb, J. A., M, *91-3.

Pottbb, E. C.. V. *90-00.

♦PoTTBB, William B., M, *78-80; P, *88. tPowBUJ. W., V, *82-3. fPBiMBrpD, Jb., M, *71-3.

Quabbib, Bbbtbam D., D, *24-25.

♦Ralston, W. C.. V, *00-1, *09-10.

Rand, Chablbs F., C, *10-12; D, *12, *16-25; P. *18; T. 22-i5.

. ♦Rand, *rHBODOBB D., T, *73-02.

♦Randol, j. B., Vl*00-1. fRANDOLPH, J. C. F., M, *81-3; V, *91-2. Raymond, Robbbt M., D, *17-18; V, *18-20. 11; a Em. *11-18.

Rbqua, Mabk LV, *17-19.

Rbyndbbs, j. V. W., D. *10-21; V, *22-24; P, *25. ♦Rzobabds, Josbph W., V, *10-11; C, *12; D, *13-15; V, *16-17.

Riohabds, Robbbt H., V, *79-80; R *86. Rxckabd, T. A., M, *94-6; D, *05; C, *05-a Ribs, Hbinbioh, M, *08-4; C. *05. fRoBBBTS, Pbbcxyal, Jb.. M, *80-2; V, *89-90. tRobbbtson, KBNNBTm M, '88-90.

Robbbtson. Wm. F., C, *06-8.

Robinson, Bubb A., s. *18-17.

Robinson, C. 8., *18.

Roobbs, Allbn H., D, *17-19.

Rolkbb, C. M., M, *88-00.

Rothwbll, Richabd P., M, *71, *98-00; V, *73-3. *75-6; P. *82.

Salbs, Rbno H.. D, *28-25.

Saundbbs, W. L., V, *09-10, *14; P, *15; D *16, *17.

Sauvbub, Aibbbt, V. *10. *11.

Shabplbss, FBbdbbicx F., 8, £, *21-25; 8. Em., *25.

tSHBAPBB. W. L., M, *93-5.

♦Shinn, William P., V, *77-8; P, *80.

Shocklby, William H., C, *08-10. fSHOOK, A. M.. M, *03-5.

Smith, Fbank M., V, *23-25.

Smith, Ob bob (ms, D, *21-25.

Smock, John C.. M, *75-7, *91-3.

Smyth, Hbnby L., D, *14-16. tSNOw, Chas. H.. M, *04; C, *05-6; D, *05-10. ♦Stanton, F. McM., m, *97-9.

♦Stanton, John, V, *92-8.

♦Stbabns, I. A., V, *05-6.

Stbabns, T. B., D,* 16-18, *22-24.

♦ C. A., V, 85-6, 95-6.

Stonb, G. C., SD, *12; D, *18-19; T, *13-18. Stoughton, Bbadlby, S, £. *13-21. ♦Stbuthbbb, j., e, *03-5; s, '06-10; t, E, *06-12;

D, 11; S, 4i-12.

SwBBTSBi Ralph, H., V, *25.

♦Swoybb, J. H., V, *71.

♦Symons, W. R.. V, *71-2: M, *73-4.

Taylob, Samubl a., D, 45-20.

♦Taylob, W. j., M, *90-2, *90-01.

Thacbbb, Abthub, D. *18-20.

Thaybjl Bbnjamin B., V, *12-13, *24; P, 14;

♦Thomas, David, P. 71.

♦Thomas, Samubl, v, *70-80.

♦Thompson, Chablbs O., V, *81-2.

♦Thubston, Robbbt H., V, 78-9.

♦Valbntinb, M. D., M, *02-4.

Walcott, C. D., Y, *04-5.

Walxbb, Abthub L., D, *11.

♦Walkbb, W. R., D, 49.

WBBBTBm WiLUAM R., M, *95-7.

♦, j. D., V, *86-7; M, *90-2; P. *95. ♦Wbllman, 8. T., V, *83-4: M, *90-2.

♦Williams, Gabdnbb F., V, *11-12.

Williams, T. M. *71.

♦Williamson, J. Pbyob, T, 71-2.

♦Winchbll, H. V., M, 01-8; V, *09-10; P, *19;

Winslow, A.. M, *90-01.

♦WlTHBBBBB, ThOS. F., M, *76-8.

Wood, Waltb C, '06-8.

Wbathbb, W. E., D, *21-23.

♦Young, Edwabd L., C, *11-12; D, 13-14.

*Deeesaed. f Non-member st present.

HONOBT IfXlfBBBS

Honorary Members

Fbanx Dawson Adams

WiLUAM Cothbsbt Blackxtt.

Gsdasio Castami

Stubois Dbinkbb

Fnbdinakd Fooh

Fbdibioo Gioum

Hatom dn la Goitpilliebb

Sib Robbbt A. Hadfibld

Fbamk William Habbobd

Hoovbb

Jambs Fubmam

Hbnbi LbChatblibb

G. McDbbmid

Esbquibl Obdonbs

Albxandbb Poubcbl

Robbbt H. Richabds

Crablbs D. Walcott

Montresl, .

Raeriston, Durhsm. Englsnd.

Rome, Italy.

Merlon Station, Pa.

Paris, FVance.

Torino, Italy.

Paris, France.

London, England.

Washington, D. C.

New York. N. Y.

Paris, France.

London, England.

Mexico City, Mexico.

Paris, France.

Cambridge, Mass.

Washington, D. C.

Honorabt Membebs {Deceased)

Ybab or Ybab of

1876. Richabd Axbbman 1922

1872. Sib Lowthian 1904

1905. Andbbw Cabnbgib 1919

1892. A. Dbl Castillo 1895

1902. Manubl Mabia Contbbbas 1902

1888. A. DaubbSb 1896

1906. Jambs Douglas 1918

1884. Thomas M. Dbown 1904

1890. Mobtis Gabtkschmakn 1895

1873. L.Gbumbb 1883

1921. Hbinbicb O. Hofman 1924

1919. Robbbt W. Hunt 1923

1891. Bbuno 1905

1895. JosBPH Lb Cont 1901

1891. J.P. 1903

1899. Flobis Osmond 1912

Ybab or Ybab or

Elbctiok Dbobabb

1890. Adolph Patbba 1890

1888. Franz Pobbpnt 1895

1911. Robsitbb W. Raymond 1918

1884. Thbodob Richtbb 1898

1899. W. C. Robbbtb-Austin.. . . . 1902

1880. C. William Sibmbns 1883

1906. John E. Stead 1923

1909. Jambs M. Swank 1914

1872. David Thomas 1882

1902. Dimitbt Constantin

1873. R. ton Tunnbb 1897

1910. Tsunashibo Wada 1920

STANDING COHlOTtBfiS

Committees of the A. I. M. E.

Standing Committees

Executive

J. V. W. REYNDERS, Chairman

Sydney H. Ball William H, Bassett

J. M. CALLOW E. DaQOLYER

Finance

WALTER H. ALDRIDGE, Chairman

George D. Barron Galen H. Clevenger

Membership

E. P. MATHEWSON, Chairman

George D. Barron John A. Church. Jr.

Alternates

Lewis W. Francis Wilber Judson

Increase of Membership

JOHN A. CHURCH, JR., Chairman

Louis D. Huntoon H. N. Spicer

F. T. Rubidge

JOHN H. JANEWAYi SYDNEY H, BALL*

Library

GEORGE C. STONE,* Chairman

Alexander C. Humphreys* Frederick F. Sharpless

Papers and Publications

Executive Committee

CHARLES S. WITHERELL, Chairman F. F. SHARPLESS, Secretary PERCY E. BARBOUR F. JULIUS FOHS

Galen H. Clevenger John A. Mathews

R. J. Colony H. G. Moulton

William A. Cowan R. V. Norris

General Committee

Arthur Notman Robert Peele George C. Stone Arthur L. Walker

William H. Blauvelt

A. D. Brokaw Oliver Bowles William Campbell R. C. Canby

B. B. Gottsbbrger Henry D. Hibbard James F. Kemp Paul D. Merica

£. W. PARKER J. H. POLHEMUS SIDNEY ROLLE BRADLEY STOUGHTON ARTHUR F. TAGGART BENJAMIN F. TILLSON A. E. WHEELER A. C. VEATCH

Management of Mining and Metallurgy

Walter H. Aldridge Charles F. Rand

E. DeGOLYER, Chairman

Edgar Rickard F. F. Sharpless

Uatfl Fdb.. 1027.

Uatfl F.. 1028.

Uatfl F., 1020.

Standing Gommittebs

William H. Bassett H. M. Boylston

Research

Arthur L. Walker

William M. Corse W. Spencer Hutchinson

Cooperation with Canadian Mining Institute

E. P. Mathewson Forest Rutherford L. K. Armstrong

J. B. Tyrrell

Scholarship at Columbia University

(In ooOperntion with Woman's Auzflinry)

Sidney J. Jennings George D. Barron Arthur 8. Dwight

James Douglas Medal Committee

GEORGE C. STONE, Chairman

Until February, 1926 Until February, 1927 Until February, 1928

Charles W. Goodale Lawrence Addicks

Charles W. Merrill Paul D. Merica

Frank M. Smith John H. Janeway

Walter Douglas Frederick Laist

E. P. Mathewson

J. V. W, REYNDERS, Member ez oficio

WILLIAM H. BASSETT L. D. RICKETTS ZAY JEFFRIES POPE YEATMAN GEORGE C. STONE

Hunt Medal and Prize

Candidates selected by IRON AND STEEL COMMITTEE

J. E. Johnson, Jr., Award

Candidates selected by IRON and steel Committee

xvu

LOCAL SaonON COMlilTTSBS

Exeeutive Comimttees of Local Sections

New York

Meet! first Wednesdsy first Tuesdsy of sooh month.

C. M. WELD Chairman R. M. RAYMOND, Vice-chairman

M. H. MERRISS, SeeretanHreasurer, Niobols Copper Co. 26 Broad St., New York SYDNEY H. BALL H. N. SPICER C. 8. WITHERELL

Boston

Meets first Monday of eaeh winter month.

ROY B. EARLING. Chairman C. R. HAYWARD, Vice-chairman

HUGH E. McKINSTRY, Secretarv-treasurer, Fozcroft House, Harvard Univ., Cambridge, Mass. GEO. H. GILMAN GEO. A. PACKARD

Columbia

Holds four sessions during year. Annual meeting in September or October.

ROWLAND B. KING, HARRY W. MARSH, Vice-chairman

LYNDON K. ARMSTRONG, Seerdory-lrsotursr, 720 Peyton Bldg., Sptdcane, Wash.

FRED W. CALLAWAY, Posl Chairman SOLON SHEDD

North Pacific

U. C. BUTLER, Chairman BENJAMIN H. BENNETTS, riee-chairman

HAROLD P. FORD, Secretarp-treaenrer, 3333 Hunter Blvd., Seattle, Wash.

Byron M. Bird Thomas Davis

Southern California

RUSH T. SILL, Chairman WILLIAM L. HONNOLD, Viethairman

S. L. GILLAN, Secretarp-treasurer, 1022 Stock Exchange, Los Angeles, Cal.

Joseph Jensen Hugh K Van Wagenen

Desaix B. Myers H. V. Welch

Colorado

CARROLL H. WEGEMANN, Chairman HORACE F. LUNT, Vice-chairman

C. W. HENDERStON, Seeretary-ireaeurcr, 409 New P. O. Bldg., Denvor, Colo.

Max W. Ball George E. Collins

Montana

L. V. BENDER, Chairman

ALEX. M. McDonald, Secretarp-treaeurert

W. B. Daly

F. A. LINFORTH, Vice-chairman Apex Hotel, Butte, Mont.

A. B. McLEOD

San Francisco

Meets second Tuesday of eaeh month.

ABBOT A. HdKS, CApwmon NEWTON CLEAVELAND, Vice-chairman

a SeereUury-ireaturer, 565 Howard St., San Frandsoo. Cal.

A. Norton Johnson C. M. Eye

Pennsylvania Anthracite

R y. NORRIS. Chairmtm

CHARMSF. Vicinnan J. B. WARRINER. Viccirman

SsdretonHrsMilw. Coal Co., Wilkes-Barre, Pa.

Douglas Bunting G. H. Hadesty A. B. Jessup

CHARLES DORRANCE, Jr. JOHN M. HUMPHREY ROBERT A. QUIN

Local Section Cohm1Ttbb8

St. Louis

M. M. LEIQHTONt Chairman C. O. STIFEL, Viea-chairman

P. B. BUTLER, Vieahairman J. H. 8TEINME8CH,

WALTER E. MoCOURT, 8§erdatv4r§anir$r, WMbington UdIt., St. Loidi, Mo JOSEPH QUITERAS W. K. KAVANAUGH H. I. YOUNG J. D. ROBERTSON

Chicago

WILLIAM R. WRIGHT, Chairman FRANCIS N. FLYNN, Vice-chairman

J. H. FLETCHER, Seeretary-treasurer. 21 E. Van Buren St., Chicago, 111. .

HENRY J. FREYN DAVID LEVINOER A. C. NOfi

WILLIAM E. JEWELL G. C. McFADDEN C. C. WHITTIER

J. C. DICK, Chairman

C. T. VAN WINKLE, Sccretary-trcacurcr, Dooly Block, Salt Lake CSty, Utah.

Otto Herres, Jr. A. H. Richards

Arizona

CHARLES A. MITKE, Chaimum

WILLIAM SABEN, lot Vice-chairman IRA B. JORALBMON, 2d Viee-chainman

W. S. Boyd

I. H. BARKDOIX, Seeretantdreaemrer, Bos 1414, Globa, Aria. L. O. HOWARD

H. Stout

Nevada

a. A. HARDY, Ckairmm J. C. JONBS. Vl ot M rm m m

HENRY M RIVES, Seerclary-frwaamr. 210 Reno National Bi Bldg., Rrao. Nav EMMET D. BOYLE WALTER 8. LARSH GEO. C. RISER

John G. Kirchen John R. Reigart Alexander Wise

Mid-Continent

JOHN M. LOVEJOY. Chairman R. S. McFARLAND, Vice-chairman

C. V. MILLIKAN, Secretary-treasurer, Amerada Petroleum Corpn., Petroleum Bldg., Tulsa, Okla. T. K. HARNSBERGER ALLAN F. HINTON GEOE S. ROLLIN

Frank A. Herald James O. Lewis Walter B. Wilson

Washington, D. C.

GEORGE S. RICE, Chairman CLARENCE T. STARR, Vice-chairman

STANLEY C. SEARS, Secretary-ireaeurcr, 2122 California St., Washington, D. C.

G. F. Loughlin 8. C. Lind

Pittsburgh

ORAHAM BRIGHT. CMrmam

S. L. GOODALE, Seerdary-ireaenrer, UniraiBity of Pittaburgh, Pittsburgh, Pla.

Wisconsin

R. S. MoCAFFERY, Chairman, Univ. of Wisconsin, Madison, Wia. W. N. SMITH, Vice-chairman

Harold O. Davidson

A. K. Winchell

Local Section Committees

Ohio

H. M. BOYLSTON. Chairman

L. B. MILLER* Victhairman H. A. SCHWARTZ* Vieohairman

C. B. MURRAY, SteratanHrtantrgr. 407 Perry Payne .t develand, Ohio.

D J. Demorest K. H. Donaldson O. A. Reinhardt

Minnesota

FRANK HUTCHINSON* Chairman WILBUR VAN EVERA* Vice-chairman

MACK C. LAKE* Seeretary-tretuurer Fidelity Bldg.* Duluth* Minn.

Upper Peninsula

WILLIAM KELLY* Chairman

8. R. ELLIOTT* Secretary-treasurer Cleveland ClifFe Iron Co., lahpeming* Mioh.

Oregon

FRANK WHALLEY WATSON. Chairman GEORGE C. HOGG* Secretary-treasurer, U. 8 National Bank Bldg.* Portland, Ore.

J. H. Batcheller Frank Baillie W. W. Elmer

Philadelphia

RICHARD PETERS, JR.* Chairman

F. LYNWOOD GARRISON, let Vice-chairman T. M. CHANCE. 2d Vice-chairman

LOUIS C. MADEIRA, III, Secretary-treasurer 260 S. Broad St.. Philadelphia, Pa. FRANKLIN BACHE SE FAIRCHILD Jb. A. A. STEVENSON

H. M. CHANCE W. W. HEARNE L. H. TAYLOR, Jb.

Q. H. Clamer W. C. Neil80N Morris Williams

Henry 8. Drinker E. W. Parker

Southern West Virginia and Northeastern Kentucky

J. K. ANDERSON. Chairman

CHARLES E KREBS, Seeretary-treaevrer, 2307 Washington St., Charleeton. W. Va.

Technical Committees

Technical Committees*

l-Iron and Steel

JOHN A. MATHEWS, Chairman WILLIAM CAMPBELX, Vice-chairman

Iron Ore

JOHN H. HALL, Vicerhairman L. B. LINDEMUTH, Seereiary

R. C. Allen Ernest F. Burchard M. M. Duncan C. T. Fairbairn

William H. Blauvelt A. J. Boynton D. T. Croxton Ambrose N. Diehl

Frank D. Carney Frank H. Crockard Henry D. Hibbard

F. C. Biggert

R. A. Bull

Edgar C. Bain H. W. Gillett M. A. Grossmann Zay Jeffries

L. B. Lindemuth A. R. Maxwell

CHARLES B. MURRAY, Chairman

W. O. Hotchkiss Max Roesler

John E. Hodge Dwight E. Woodbridge

William Kelly Charles F. Rand

Blaet Furnace

WALTHER MATHESIUS. Chairman ALEXANDER L. FEILD DORSEY A. LYON C. A. MEISSNER CHARLES P. PERIN

Steel Manufacture

BRADLEY STOUGHTON, Chairman L. B. LINDEMUTH H. T. MORRIS WILLIAM J. PRIESTLEY

Mechanical Treatment

FREDERICK W. WOOD, Chairman FRANK L. ESTEP J. V. W. REYNDERS

Foundry

ARTHUR H. JAMESON, Chairman R. F. HARRINGTON ENRIQUE TOUCEDA

Carl Zapffe

Edward P. Ross R. H. Sweetser R. J. Wysor

C. F. W. Rys W. R. Shimer A. A. Stevenson

A. T. Keller

Richard Moldenke

Chemietryt Phytiee A Metallography HERBERT M. BOYLSTON, Chairman

V. N. Krivobok Albert Sauveur

F. C. Langenberg Haakon Styri

W. E. Ruder George B. Waterhouse

Open Hearth Steeel E. A, WHITWORTH, Chairman W, A. MAXWELL, JR.

L. F. Reinartz Albert W. Smith

2-Reduction and Refining of Copper

LAWRENCE ADDICKS JOHN F. AUSTIN LOUIS V. BENDER P. P. BUTLER STUART CROASDALE L. OGILVIE HOWARD L. W. KEMP MILO W. KREJCI FREDERICK LAIST

P. MATHEWSON, Chairman F. J. LONGWORTH RICHARD L. LLOYD

O. C. Martin

A. G. McGregor A. J. McNAB

P. A. Mosman A. H. Richards L. D. Ricketts Forest Rutherford

H. H. STOUT HENRY A. TOBELMANN WILLIAM J. TURNER GEORGE D. VAN ARSDALE ARTHUR L. WALKER A. E. WHEELER ALBERT E. WIGGIN C. S. WITHERELL

3-Extraction and Refining of Precious Metals

BENNETT R. BATES A. L. BLOMFIELD DEAN S. CALLAND J.JM. CALLOW ALLAN J. CLARK GALEN H. CLEVENGER J. J. DENNY

JOHN V. N. DORR, Chairman M. J. FAIRLIE DAVID L. H. FORBES W, EARL GREENOUGH CHARLES JANIN S. F. KIRKPATRICK A. D. MARRIOTT, JR. CHARLES W. MERRILL

W. O. NORTH EDWIN L. OLIVER WALTER L. REID GEORGE W. STARR FRED WARTENWEILER A. J. WEINIG

The purooee of each committee ic to further the development of the art and edenoe and to obtain papoe of nih merit for disoueeion and pubUoation by the Institute on the subject covered by the title of the committee. Personnel subject to acceptance by members named.

xxu

Tbchnical G0Mmittsb8

4-Reduction and Refining of Lead

L. DOUGLASS ANDERSON JESSE O. BETTERTON S. Q. BLAYLOCK E. E. DIEFFENBACH ARTHUR S; DWIGHT L. G. EAKINS

H. H. ALEXANDER, Chairman

Karl Eilers W. E. Newnam

EDWARD H. HAMILTON WADSWORTH W. NORTON KUNO B. HEBERLEIN RUDOLPH PORTER

Carle R. Hayward Smith

G. E. Johnson Otto Sussman

George A. Marsh

5-Reduction and Refining of Zinc

GEORGE 8. BROOKS C. P. FISKE H, W. GEPP HARRY ADAM GRINE JULIUS W HEGELER HAROLD G. HIXON

F. E. PIERCE, Chairman WALTER R. INGALLS ARCHIBALD JONES FREDERICK LA18T R. M ROOSEVELT FRANCIS P SINN B. M. O'HARRA

KURT STOCK GEORGE C STONE OTTO SUSSMAN U. C. TAINTON LELAND E. WEMPLE D. C. WRAY

6-Reduction and Refining of Uncommon Metals

R. B. MOORE, Chairman FRANK L. ANTISELL CHARLES BUTTERS CHARLES H. FULTON ERNEST GAYFORD

H W. GOULD FRANK L. HESS W. SPENCER HUTCHINSON SAMUEL COLVILLE LIND GEORGE L. NORRIS J. P. BONARDI, Secretary

EDWIN L. OUVER B. D. 8AKLATWALLA CARL J. TRAUERMAN a Y. WANG WILLIS R. WHITNEY

7-Coal and Coke

HOWARD N. EAVENSON, Chairman

RAY W. ARMS WILLIAM H. BLAUVELT D. J. CARROLL ANDREW B. CRICHTON 8. D. DIMMICK T. M. DODSON CHARLES DORRANCE, JR H. S. QEISMER

G. B, HADESTY ROBERT HAMILTON L. S. HOLSTEIN ALBERT B. JESSUP F. F. JORGENSEN C. E. LE8HER CHESTER M. LINGLE HARRY WILLIAM MONTZ

DOUGLAS BUNTING, Vice-chairman CHARLES G. MORGAN EDWARD W. PARKER ROBERT A. QUIN GEORGE S. RICE C. W. SMITH JOHN I. THOMPSON J. B. WARRINER A. C. WATTS

H. RIES, Chairman L. K. ARMSTRONG GEORGE H. ASHLEY R. J. COLONY HOWELLS FRECHETTE

8-Non-metallic Minerals

Hoyt S. Gale Raymond B. Ladoo Robert Linton E. S. Moore

Oliver Bowles,

David H. Newland W. C. Phalen N. C. Rockwood Frank A. Wilder

9-Ground Movement and Subsidence

Henry S.

H. G. MOULTON, Chairman

GEORGE ASHLEY DOUGLAS BUNTING LOUIS 8. CATES T. CONNER HOWARD N. EAVENSON HORACE REYNOLDS GRAHAM LESTER E. GRANT

MUNROB, Honorary Chairman W. O. HOTCHKISS C. B. LAKENAN F. W. MACLENNAN BRUCE A. MIDDLEMISS THOMAS H. O'BRIEN EDWARD O'TOOLE SIDNEY PAIGE ROBERT E. PALMER FRANK H. PROBERT GEORGE S. RICE, Secretary

MILNOR ROBERTS FREDERICK W. SPERR A. C. STODDARD JOHN M. SULLY BENJAMIN F. TILL80N H. B. TREICHLER C. E. VAN ORSTRAND POPE YEATMAN L. B. YOUNG

TBCHNICAX COMMITTSBS xxiii

lO-Mining Methods .

S. M. RATMOND, Chairman B. B. QOTTSBERGEB, A$oc%ate Chairman

H. Foster Bain W. O. Hotchkiss John Uno Sebenius

W. R. Crane Sidney J. Jennings George Otis Smith

Howard N. Eavenson Seeley W. Mudd J. Edward 8Purr

H. A. Guess R. V. Norris William Y. Westervelt

John E. Hodge Frank H. Probert Pope Yeatman

F. W. SPERR, Chairman

Robert Linton R. M. Raymond

AnthraeUe Coal R. V. NORRIS. Chairman

Dever C. Ashmead Douglas Bunting Herbert D. Kynor

J. B. Warriner

BiiuminouM Coal

HOWARD N. EAVENSON. Chairman

THOMAS H. CLAGETT DONALD H. McDOUGALL SAMUEL A. TAYLOR

Frank Haas M. F. Peltier C. M. Young

George 8. Rice

C. L. Berrien Norman B. Braly

CopperN orthwou

WILLIAM B. DALY, Chairman JAMES L. BRUCE JOHN GILLIE

Frank A. Kennedy

Louis S. Cates J. H. Hensley Ira B. Joralemon Henry Krumb

GERALD F. SHERMAN. Chairman C. B. LAKENAN CHARLES A. MITKE ARTHUR NOTMAN M, OTAGAWA

H. DuWITT SMITH JOHN M. SULLY ROBERT E. TALLY

John Knox

Copper-'hohe Superior FRED W. DENTON. Chairman

W. H. Schacht

TRUMAN H. ALDRICH CLARENCE E. ABBOTT C A. BARABE S R. ELLIOTT EDWARD W. HOPKINS

DONALD B. GILLIEK Chairman EARL E. HUNNER CHARLES F. JACKSON CHARLES E. LAWRENCE F. U. NELSON EMERSON D. McNEIL

W. J. Penhallegon Harrison Souder Francis J. Webb Carl Zapffe

Henry A. Buehler Allan B. Calhoun R. M. Catlin Stanly A. Easton

Load and Zinc

ARTHUR THACHER. Chairman CECIL FITCH WALTER FITCH H. A. GUESS ROBERT S. LEWIS

JAMES F. McCarthy PHILIP N. MOORE FRANCIS A. THOMSON BENJAMIN F. TILLSON

Philip R. Bradley J. A. Burgess George E. Collins

Precious and Bare Metals

GEORGE A. PACKARD. Chairman JOHN A. FULTON EDWIN HIGGINS W. SPENCER HUTCHINSON

John G. Kirchen Hugh Rose

Willard A. Cole William B. Daly John A. Fulton

Samplinff and BsHmatino

IRA B. JORALEMON. Chairman B. B. GOTTSBERGER H. C. JENISON HENRY KRUMB CHARLES A. MITKE

Basil Prescott J. F. Wolff Philip D. Wilson

Non-mslallie Minerals RIES. Chairman

Technical Committees

ll-Mining Geology

E. F. BURCHARD. Chairman FREDERICK J. ALOOCK OBORQS H. ASHLEY SYDNEY H. BALL

J. Austen Bancroft Bd80N & Bastin

H. A. Bubhler

Edwin J. Coluns

Q. B. Corlb88

Harold B. Culver Edwin E. Ellis

L. C. Qraton

George H. Garrey Donnel F. Hewett

W. O. Hotchkiss

Ira R Joralemon

James F. Kemp

Cyril W. Knight

Henry Krumb

Alfred C. Lane Waldemar Lindqren

R. J. COLONY, Ssersiary BENJAMIN L. MILLER BLWOOD 8. MOORE WILBUR A. NELSON JOSEPH HYDE PRATT HEINRICH RIBS RENO H. SALES FRED 8EARL8. JR CHARLES H. WHITE RUSH J. WHITE

12-Minmg Equipment

W. L. Affelder

Henry S. Qeismer

GRAHAM BRIGHT. CLimon HARRY C. GOODRICH

R. E. Hobart

A. B. Kiser

L. F. Mitten Vernon 8. Rood Humphrey D. Smith

13-Mine Ventilation

CLARENCE E. ABBOTT WILLIAM H. BLAUVELT EDWARD E. BUGBEE LOUIS 8. CATES

THOMAS H. CLAGETT w L. Comings

H.' Qeismer

GEORGE S. RICK Chairman

E. A. HOLBROOK, Secretary

W. O. Hotchkiss

G. R. Jackson

Sidney J. Jennings

Mack C. Lake

JAMES F. McCarthy SEELEY W. MUDD

E. W. Parker

FRANK H. PROBERT ROBERT M. RAYMOND E. J. RISTEDT GERALD SHERMAN CECIL W. SMITH ROBERT E. TALLY THOMAS D. THOMAS

Coal Mining

Howard N. Eavenson Charles Enzian

FRANK HAAS, Chairman

J. W. Paul

J. J. Rutledge C. M. Young

MeUd Mining

W. S. Boyd

W. B. Daly

B. B. GOTTSBERGER, Chairman STANLY A. EASTON

Daniel Harrington

Charles A. Mitke

Phyeiologicdl Studies

C. L. Berrien

R. R. SAYERS, Chairman

W. D. Brennan

J. J. Forbes

A. J. Lanza

Ventilation Physics

Ray W. Arms

James T. Beard

ALFRED C. CALLEN, Chairman THOMAS FRASER

GEORGE E. Mcelroy

A. S. Richardson Walter S. Weeks

Fans

Louis W. Huber

GRAHAM BRIGHT, Chairman

L. F. Mitten

Conservation of Mine Timber

CHARLES H. MacDOWELL, Chairman

R. L. Adams

W. F. Affelder

R. V. ageton

W. L. Cuming8

Henry 8 . Drinker

Erle V. Daveler

A. B. Foote

H. H. Hasler

R. R. Hornor

E. A. Holbrook

George R. Jackson

W. J. PENHALLEGON JOSEPH HYDE PRATT GERALD F. SHERMAN GEORGE 8. RICE R. G. WAYLAND

Technical Cokmittbbs

IS-Mine Taxation

CORNELIUS KRLXiEYf ChotTfiwn

R. C. Allen Ralph E. Davis

Paul Armitage H. B. Fernald

William B. Gower

R. V. Norris Walter Wood

16-Milling Methods

ROBERT H. RICHARDS, Honorary Chairman GALEN H. CLEVENGER, Chairman JOHN V. N. DORR. Vieohairman CHARLES E. LOCKE. Vteoirman

FREDERICK LAIST, Vieohairman

Paul W. Avery Earl S. Bardwell John W. Bell

C. H. Benedict Francis L. Bosqui Frederick W. Bradley

D. G. Browne

H. KENYON BURCH DEAN S. CALLAND JOHN M. CALLOW ROBERT C. CANBY ALLAN J. CLARK DAVID COLE ARTHUR CROWFOOT FRED S. CURTIS ERLE V. DAVELER

E. W. Davis Rudolph Gael

ARTHUR O. GATES H. W. GEPP H. A. GUESS R. S. HANDY HENRY HANSON H. W. HARDINGE ERNEST A. HERSAM THEODORE J. HOOVER MICHAEL H. KURYLA

C. B. Lakenan Luther W. Lennox Robert 8. Lewis

D. A. Lyon

A. D. MARRIOTT. JR. CHARLES W. MERRILL LOUIS D. MILLS HENRY 8. MUNROE EDWARD H. NUTTER

JOHN GROSS, SocroUay

T. M. OWEN C. Q. PAYNE JOHN B. PORTER OLIVER C. RALSTON L. D. RICKETTS W. N. R08SBERG LEWIS G. ROWAND THEODORE SIMONS

E. T. STANNARD WALTER G. SWART ARTHUR F. TAGGART ARTHUR THACHER GEORGE D. VAN ARSDALE A. J. WEINIG ALBERT E. WIGGIN R. B. YERXA

17-Industrial Relations

NEWELL G. ALFORD ALEXANDER C. BEESON HAROLD O. BOSWORTH WILL L. CLARK WILLIAM H. COBURN W. C. COFFIN

F. F. Colcord

G. M. Colvocoresses Cleveland E. Dodge J. V. N. Dorr

H. S. Gilbertson Charles W. Goodale

ARTHUR NOTMAN, Chairman SIDNEY ROLLE, Secretary

B. Britton Gottsberger

J. N. Houser "

S. Pemberton Hutchinson S. J. Jennings Frederick Laist

C. B. Lakenan A. J. Lanza Robert Linton Horace F. Lunt H. G. Moulton

Harold S. Munroe W,

H. D. PALLISTER J. W. PAUL JAMES C. REA EDGAR RICKARD ALLEN H. ROGERS L. K. 8ILLCOX ROGER W. STRAUS ROBERT E. TALLY J. EDWARD SPURR W. ROGERS WADE F. G. WALLOWER REUBEN WEBSTER

L. D. Frink

Employment and Induetrial Organization

EUGENE F. IRWIN, Chairman HORACE MOSES

w. G. McBride

John L. Boardman

Safety

B. F. TILLSON, CAotrman

R. Dawson Hall

John T. Ryan

G. M. Gillette

D. Harrington

W. R. Chedsey

Education

Rush N. Hosler

H. M. Wolflin

Stanly A. Easton

C. R. Hook

Physical and Mental Faetore in Industry

E. R. SAYERS, Chairman

T. T. Read

John A. Church, Jr. A. O. Ihl8Enq

Tsohnical C0Mm1Ttbb8

18*Acooimting Methods

H. B. FBRNALD. CMtwum R. VAN A. NORRIS. JR. ROBERT M. RAYMOND

H. T. Van Ict.Th Qeorqb F. Wolff

Stanly A. Easton Louis S. Cates W. J. Lorinq

19-Engmeermg Education

WILLIAM KELLY, Chairman DORSEY A. LYON ALLEN H. ROGERS

Robert E. Tally E. E, Thum C. M. Weld

20-Production and Use of Silver

CORNELIUS F. KELLEY. Chairman

F. H. Brownell W. Montague Ferry F. Y. Robertson

John O. Kirchen

Professioiial Divisions

I — Institute of Metals Division*

GEORGE K. ELLIOTT. Chairman

GEORGE C. STONE. rtc-eAatrfiKifi WILLIAM M. CORSE. SaerrtanHrroiurrr

D. K. Crampton W. K. Frank H. W. Guxett

Executive Committee

Samuel L. Hoyt Zay Jeffries H. C. Jennison Stanislaus Skowronski

R. L. Suhl A. E. White R. F. Wood

II — Petroleum Divisionf

F. JULIUS FOBS, Chairman

EDWARD L. ESTABROOK, Vice-chairman C. P. WATSON, Secretary-treasurer

Industrial Preparedness

To CoOpmte with the U. S. War Department

Oenerdl Committee

ARTHUR a DWIGHT. Chairman H FOSTER BAIN C. K. LEITH

H. a MULLIKBN AUemaie GEORGE OTIS SMITH

J. Edward Spurr Pope Yeatman

of high merit for pnbHoatSoB by the Inifttti

t & pnrpoee M tito ia to oMn imen of Mch merit for pnbUeation by Uie Inetitnte on

doetioB, traaeportatlon. reflnini and oCOiiatimi of petroleum and ite produete.

BBFBESENTATIVES IN OTHEB OBGANIZATIONg

Bvb-eonmUUei

Chronu

ALBERT BURCH, Chairman

E. F. BURCHARlb FRANK PROBERT

Vanadium

W. SPENCER HUTCHINSON. Chairman HAROLD BOERICKE

F. L. Hess

Platinum

AMOR F. KEENE, Chairman J. M. HILL JOSEPH A. SCHLOSS

FRED W. BRADLEY, Chairman O. H. HERSHEY A. Q. McKENNA

Mtreury

GEORGE J. YOUNG. Chairman MURRAY INNES F. L. RANSOME

Oraphita

BENJAMIN LbR. MILLER, Chairman EDSON S. BASTIN HENRY A. WENTWORTH

Petrolaum

A. C. VEATCH, Chairman VAN H. MANNING CHESTER W. WASHBURNE DAVID WHITE

Tin

G. T. BRIDGMAN, CAairman

H. H. Alexander

J. W. Furness D. F. Hewett

Manganua

C. M. WELD. Chairman ROBERT LINTON JOHN A. MATHEWS

J. V. W. Reynder8 Bradley Stoughton

Societies, Boards, Etc., on Which Institute Has Representation

United Engineering Society

WILLIAM L. SAUNDEBS, Fruident

GEORGE H. PEGRAM, 1st Vics-prssuient ALFRED D. FLINN, Sserstarp

J. V. W. REYNDERS, 2d Vicprsridant JACOB S. LANQTHORN, Trsaturrr

HENRY A. LARDNER, AsrUtant Treasurer

J. Vipond Davies

Finance Committee

GEORGE H. PEGRAM, Chairman BANCROFT GHERARDI WILLIAM L, SAUNDERS, ea-ajSlcio

W. F. M. Goss

House Committee

ALFRED D. FLINN, Chairman FREDERICK F. SHARPLESS* GEORGE T, SEABURY

CALVIN W. RICEt

F. L. HUTCHINSONt

Until January, 1926 GEORGE H. PEGRAM J. V. W. REYNDERS* W. F. M. GOSSt HENRY A. LARDNERt

Trustees

Until January, 1927 LEWIS D. RIGHTS WALTER H. ALDRIDGE* ROY V. WRIGHTt H. H. BARNES. JR.t

Until January, 1928 WILLIAM J. WILQUS4 J. VIPOND DAVIES* WnXIAM L. SAUNDERSt BANCROFT GHERARDli

Committee on Entrance HaU and Memorials

J. V. W. Reynders*

BANCROFT GHERARDI.t Chairman W. F. M. GOSSt

William J. Wilqus4

A. I. M. E.

t A. S. M. E.

e A. S. C. E.

t A. I. B. E.

Bbpbesentatives In Other Oboanizations

library Board of United Enginemng Society

SYDNEY H. BALL, Chairman

EDWARD D. ADAMS, Vice-chairman HARRISON W. GRAVER, Secretary

W. W. Macon

Executive Committee

Edward D. Adams John H. Janeway

Lincoln Bush

Sydney H. Ball*

GEORGE C. STONE* ALEXANDER C. HUMPHREYS* JOHN H. JANEWAY* FREDERICK F. SHARPLESS* LINCOLN BUSH

C. W. Hubbell0

Members

WALTER E. SPEARS F. H. CONSTANT GEORGE T. SEABURY W. C. WETHERILLt HENRY A. LARDNERt PERCY H. THOMASt W. W. MACONt

CALVIN W. RICEI E. B. CRAFT: EDWARD D. ADAMS: W. I. BLIGHTER: A. W. KIDDLE: F. L. HUTCHINSON

Engineering Foundation

L. B. STILL VTELL, Chairman

EDWARD D. ADAMS, 1st Vice-chairman JACOB S. LANGTHORN, Treasurer

ELMER A. SPERRY, 2d Vice-chairman ALFRED D. FLINN, Director

Edward D. Adams

Executive Committee

L. B. STILL VELiL, Chairman GEORGE A. ORROK ELMER A. SPERRY

Arthur L. Walker

J. Vipond Davies*

Arthur L. Walker* H. M. Boylston* Edward D. Adams

Elmer A. Sperry

Trustees of United Engineering Society

GEORGE H. PEGRAM0 W. F. M. GOSSt

Members Nominated by Founder Societies

ROBERT RIDGWAYa ARTHUR M. GREENE, JR.f GEORGE A. ORROKt

Members at Large CHARLES F. RAND

Bancroft Gherardij

GANO DUNNl L. B. STILLWELLi

Arthur D. Little

Ex-officiOf President of United Engineering Society WILLIAM L. SAUNDERS

Society for Promotion of Engineering Education

A. I. M. E. Representatives on Board of Investigation and Coordination WILLIAM KELLY ALLEN H. ROGERS

American Engineering Standards Committee

C. E. SKINNER,t Chairman

CHARLES RUFUS HARTE,* Vice-chairman P. G. AGNEW, Secretary

GEORGE C. STONE* H. H. QUIMBY STANLEY G. FLAGG, JR.t

GRAHAM BRIGHT* MILO S. KETCHUM H. S OSBOfeNEi

GEORGE E. THACKRAY* FRED E. ROGERSt H. M. HOBARTt

CHARLES A. MEAD CLOYD M. CHAPMANf

AUematee Representing A. I. M, RICHARD L. LLOYD; HARLOWE HARDINGE

Also representatives of other technical societies, Government departments and industrial associa* Uons.

Mining Standardization Correlating Committee

Graham Bright

A. /. M. E. Representatives

H. N. Eavenson

♦A. I. M. E.

t A. 8. M. E. t A. I. E. E.

0 A. S. C. E.

Amer. Eleo* Ry, Assn.

Bepbb8Entatives In Otheb Obqanizations

Division of Eneering and Industrial Research National Research Council

GEORGE K. BURGESS, Viehairman EDWARD B. CRAFT, Vice-chairman

FRANK B. JEWETT, Chairman

R. B. Moore*

W. Spencer Hutchinson* William H. Bassett* Frederick F. Sharpless*

E. W. RICE. JRt BANCROFT GHERARDIJ A. E. KENNELLYt

F. L. HUTCHINSONt ALBERT KINGSBURYt

EDWARD D ADAMS GEORGE K. BURGESS JOHN R. FREEMAN W. H. FULWEILER F. P. GILLIGAN FREDERICK L. HOFFMAN

R. J. S. PIGOTTt

G. A. ORROKt CALVIN W. RICEt

H. H. Porter

W. K. Hatt

Henry Goldmark George T. Seabury

J. A. CAPPtt GUILLIAEM AERTSENtt

Memhere at Large

SULLIVAN W. JONES PAUL M. LINCOLN ELBERT C. LATHROP ARTHUR D. LITTLE CHARLES F. LOWETH THOMAS H. Macdonald

MAURICE HOLLAND, Director WILLIAM SPRARAGEN, Secretary DUGALD C. JACKSONt F. W. DAVIS* B. B. BACHMAN* F. PAUL ANDERSON* F. E. MATHEWS* HENRY M. HOBART* EDMUND O. SCHWEITSER* A. E. WHITE*

ANSON MARSTON H. F. MOORE HERMANN VON SCHRENK AMBROSE SWASEY F. P. VEITCH E. D. WALEN

William L. Saunders.*

W. L. R. EMMETt SPENCER MILLERt FRANK J. SPRAGUE: ALFRED CRAVEN ANDREW M. HUNT0

Naval Consulting Board

THOMAS EDISON, President Chairman B.

THOMAS ROBINS.* Secretary LAWRENCE ADDICKS> ELMER A. SPERRYa BION J. ARNOLD**

L. H. Baekeland**

W. R. Whitney**

M. R. Hutchinson*

B. THAYER,* Vice-chairman

DAVID W. BRUNTON*' HOWARD E. COFFIN* ANDREW L. RIKER* HUDSON MAXIM* MATTHEW B. SELLERS*

John Fritz Medal Board of Award

FRED J. MILLER, t Chairman ALFRED D. FLINN, Assistant Secretary

GEORGE S. WEBSTER, 0 Secretary ARTHUR S. DWIGHT.* Treasurer

Herbert Hoover* Charles S. Loweth0 Farley Osgoodj

WILLIAM KELLY* C. E. GRUNSKY WILLIAM McCLELLANJ

CHARLES F. RAND* H. B. SARGENTf HARRIS J. RYANJ

JOHN R. FREEMAN* FRED R. LOWt FRANK B. JEWETTt

W, F. M. GOSSt

Joseph A, Holmes Safety Association

H. Foster Bain T. T. Read

Executive Committee

W. H. Bixby George S. Rice* John L. Lewis

J. F. Callbreath William Green

Hero Medal Committees

Minirg and Quarrying Industries ROBERT LINTON EDGAR WALLACE

Metallurgical and Other Industries GALEN H. CLEVENGER JOHN TURNEY

J. W. Paul

Van H. Manning

A. I. M. E. t A. 8. M. E.

nium. Engr. Soo.

Amer. Soo. Automot. Engn.

Amer. Soo. Heat, and Vent. Engrs.

Amer. Soo. Refrm. Engra.

Amer. Welding Soo.

Weetern Soo. Engre.

*Amer. Soo. for Steel Treating

Appointed by See. of Nary.

: A. I E. E. A. S. C. E. ft A. S. T. M. Invonton* Guild.

Amer. Eleetroohem Boo.

Amer. Soo. Aeronaut. Engra.

Amer. Chem. Boo.

War Com. Teeh. Soo.

Amer. Aeronaut. Soo.

Amer. Boo. Automot. Bngra.

BBFBBSBNTATtVBS IN OTHBB OBGANIZATIONS

American Aaaodation for Advancemrat of Sdenoe

A, X. M. S, R€pr§9mUaH9$9

Waldemar Lindoren Albert 8Auveur

Also repreientatiyeB of about forty other aasooiatSoiiB.

Washington Award Commission

EDGAR S. NETHERCUT. Secretary CHARLES H. MaoDOWELL* HERBERT S. PHILBRlCKf F. K. COPELAND* CHARLES R. RICHARDSf

JOHN PRICE JACKSONt D. H. MAURY}

CHARLES P. SCOTTt C. A. MORSEI

R. C. Marshall, Jr. W. L. Abbott}

W. H. Finley Andrews Allen}

J. L. HECHT, W. W. DbBERARD H. H. CLARK GEORGE W. HAND PAUL WESTBURG

Franco-American Engineering Committee

(Organised 1919 to foster engineering relations between France and America)

George F. Swains F. G. Cottrell*

ARTHUR S. DWIGHT* CHARLES T. MAINt GEORGE W. FULLERt

L. B. STILLWELL! A. M. HUNTi

American Bureau of Welding

A, 7. M. B, ReprMMtaHw BRADLEY STOUGHTON

Joint Conference Committee of Founder Societies

Robert Ridgway

George T. Seabury

►A. I. M. E. t A. S. M. E.

J. V. W. REYNDERSt* Chairman FREDERICK F. SHARPLESS,* Secretary

W. F. DURANm CALVIN W. RICIEt

t A. 1. E. E. A. S. C. £.

FARLEY OSGOODl F. L. HUTCHINBONt

Western Boo. Engrs.

Proceedings

Birmingham Meeting, 1924

The 130th Meeting of the Institute was held at Birmingham, Ala., Oct. 13 to 15, with visits to other mines and districts. There were 71 members and guests on the special train from Washington; 55 from outside of Birmingham and 183 local members and guests made the total registration 309.

The party assembled at the New Willard Hotel, Washington, D. C., on the afternoon of Oct. 7. The men visited the Bureau of Standards and the Bureau of Mines; the women enjoyed an automobile sightseeing trip around Washington. In the evening a banquet was given by the Washington Section. George S. Rice, chief mining engineer of the Bureau of Mines, presented the Hon. Herbert Hoover as toastmaster; the speakers were President William Kelly and Past-President Arthur S. Dwight. The dinner was followed by dancing until midnight, when the party left on the special train for the South, The next day was spent in visiting the Luray Caverns and the Grottoes in the Shenandoah Valley.

Wednesday evening the special train arrived at Roanoke where a brief reception was held at the Hotel Roanoke and plans were outlined for the coal mines trip the following day. Edmund C. Pechin, one of the two living Founder Members of the Institute, resides within 20 miles of Roanoke but could not be present to greet the members. He is approaching his 90th year and, although in good health, could not attend the reception because it occurred in the evening. He would have done so, had it been held in the afternoon. Cordial greetings were sent to him by the members present.

Visit at Bluefield

Thursday found the party at Bluefield, W. Va., by invitation of the Pocahontas Operators Association. An illustrated booklet giving the geology and history of the Pocahontas district and a mile to mile itinerary of the 90-mile automobile trip through the coal fields, was distributed. In the booklet was an extract from the proceedings of the meeting of the Institute held in Roanoke, Va., in 1883, and a list of the members present at that meeting. John Graham, who was present at that meeting, was one of the hosts this year. Col. Edward O'Toole was a most excellent host at the U. S. Steel Corpn.'s headquarters at Gary.

Visit at Mascot and Copperhill

Mascot, Tenn., was reached on Friday morning, the 10th. The party alighted on the property of the American Zinc Co., where a large

Birmingham Meeting, 1924

tent served as an office for any requiring such service. A nicely printed program of the day and a visitor's card to the Cherokee Country Club were given to each member of the party, through the courtesy of J. H. N. Houser, general manager of the Tennessee Copper Co. The Tennessee Geological Survey had prepared and labeled for each member a package containing a marble bulletin, a zinc map, a state map, and a mineral map. The party was then conducted underground where the mining methods were explained by H. A. Coy, mine superintendent. A trip was made through the jig and dotation plants, after which the party was taken to Community Hall for luncheon. At each cover was placed a carton containing a bottle of white zinc oxide and one with jig and flotation tailings, souvenirs of the American Zinc Co.; also a black leather sack filled with Mascot lime, by the American Limestone Co., of Knoxville. Brief addresses of welcome were given by H. 1. Young, the manager, and H. A. Coy; they were responded to by President Kelly and Arthur Thacher.

In the afternoon, the golfers were taken to the Country Club; the rest of the party were either taken on sightseeing trips through the city of Knoxville or to the various famous marble quarries within a radius of 15 or 20 miles and to the mill of the Knoxville Marble Co., where cutting and polishing the marble was shown and paper weights of polished marble were distributed.

In the evening, there was a formal dinner at the Whittle Springs Hotel. Col. William S. Shields, president of City National bank, was toastmaster. Director Frank Bane, of the Department of Public Welfare, welcomed the guests to the city. Other speakers were President William Kelly, Dr. Harcourt A. Morgan, president of the University of Tennessee; Past-President P. N. Moore, of St. Louis, and Wilbur Nelson, state geologist.

Saturday morning, the special train left Knoxville and arrived at Copperhill at noon. An attractive eight-page folder, describing the plant and operations to be visited, and a train schedule to the various places were distributed as the members of the party left their train for the special train of the Tennessee Copper Co., which took the party to the plant. Luncheon was served in the clubhouse of the Cowanee Club of the Tennessee Copper Co. At each cover was a large ash tray of T. C. Co. blister copper as a souvenir. J. N. Houser welcomed the party to Copperhill; his toast was responded to by President Kelly and E. F. Eurich, who told of the camp and plant as they were when he was employed here just after his graduation in 1866. After luncheon, the party visited the London shaft and flotation plant, then the McPherson shaft of the Burra Burra mine where some went underground while the rest visited the smelter and acid plant at Copperhill.

Birmingham Meeting, 1924

Chattanooga and Birmingham

Sunday morning, the party arrived in Chattanooga. The Engineers' Club of that city provided automobiles for trips to the battlefields at Lookout Mountain, Missionary Ridge, and Chicamauga and conveyed the party to the Signal Mountain Inn for luncheon.

Sunday night, the special train reached Birmingham. Very attractive and elaborate booklets, entitled Little Journey in the Birmingham District," and 'Mining and Steel Making Methods in Alabama," published by the Tennessee Coal, Iron & Railroad Co., together with tickets for all the functions, were distributed to the members and guests as they registered.

Technical Sessions

Monday was devoted to technical sessions held at the meeting headquarters at the Tutwiler Hotel.

Morning Session

Chairman, George Gordon Crawford

Coal Washing Practice in Alabama. H. S. Geismer.

Byproduct Coking in Alabama. F. W. Miller.

Alabama Coal Mining Practice. Milton H. Fies.

Afternoon Session

Chairman, Frank H. Crockard

Blast-furnace Practice in Alabama. H. E. Mussey.

Steel Making in Alabama. J ames Bowron.

Production of Ferrophosphorus in the Electric Furnace. Theodore Swann. Manufacture of Ferrophosphorus at Rockdale, Tenn. James A. Barr.

Manufacture of Cast-iron Pipe in the South. Richard Moldenke.

Evening Session

Chairman, T. H. Aldrich, Sr.

Economic Geology of the Birmingham District, Alabama. Ernest F. Burchard and Charles Butts.

Red Iron Ore Mining Methods in the Birmingham District. W. R. Crane.

Roof Support in the Red Ore Mines of the Birmingham District. W. R. Crane

Visits in the Birmingham District

Tuesday and Wednesday the entire party was taken by special trains, provided by the Alabama Mining Institute, to many of the mines and plants. A barbecue was given at Bayview by the Tennessee Coal, Iron & Railroad Co., and on Wednesday another was given at the Phoenix plant of the Phoenix Portland Cement Co.

Birmingham Meeting, 1924

Tuesday night there were two dinners at the Tutwiler. One was for those interested in the subject of industrial relations; the other was given by the Directors of the Institute and many yoimger members of the Institute were among the guests. At the latter, there was a general discussion of Institute affairs and con Crete suggestions for progress. Following the dinners, in the Phillips High School Auditorium, the Colored Concert Choir of the Sixteenth Street Baptist Church rendered a program of southern songs in a dialect and manner new to the northern visitors. Moving pictures of the diversified interest and activities of the district were shown by the Alabama Power Co.

Wednesday night, a banquet and a dance were given at the Birmingham Country Club by the Alabama Mining Institute. George G. Crawford was toastmaster and his welcome to Birmingham was responded to by President William Kelly. The principal speaker of the evening was J. V. W. Reynders, first vice-president of the Institute.

John MacLeish, Director of Mines Branch, Department of Mines of Canada, was the last speaker; he voiced his appreciation of the Birmingham district and conveyed the felicitations of the Canadian Mining Institute, which he represented.

Thursday afternoon was spent inspecting the Wilson Dam and U. S. Nitrate Plant at Muscle Shoals.

Meeting Institute Op Metals Division

Institute of Metals Division Meeting

The annual joint meeting of the Institute of Metals Division and the American Foundiymens Association was held at Milwaukee, Wis., Oct. 6-11. At the Non-ferrous Metals Session, the following papers were presented:

Casting and Heat Treatment of Some Aluminum-Copper-Magnesium Alloys. Samuel Daniels, A. J. Lyon, and J. B. Johnson.

Experiments on the Heat Treatment of Alpha-Beta Brass. O. W. Ellis and D. A.

Schemnitz.

Coatings Formed on Corroded Metals and Alloys. Geobgb M. Enos and Robebt J. Andebson.

Hardness of Heat-treated Aluminum Bronze. Geobgb P. Comstock.

XXX vm

New York Meeting, 1925

The 131st meeting of the American Institute of Mining and Metallurgical Engineers was held in New York on Feb. 16 to 20, 1925, with a lair registration than at any previous meeting, the total being 1320.

Dr. John A. Mathews, of New York, delivered the Henry M. Howe Memorial lecture; the title of his lecture was "Austenite and Austenitic Steel."

Dr. Carl Benedicks, of Sweden, delivered the annual lecture of the Institute of Metals Division; the title of his lecture was "Studies on the Corrosion of Condenser Tubes with Special Reference to Hot-wall Action and Segregation."

Considerable interest was shown in the various symposiupas. The annual symposium on petroleum is now looked forward to by all persons interested in oil and gas. The coal and coke s 3 Tnposium aroused so much discussion that an extra session was necessary for the presentation of the papers. At joint sessions with the Mining Section of the National Safety Council, under the auspices of the Industrial Relations Committee, rock dusting was discussed.

A joint meeting with the Mining and Metallurgical Society of America and the Mining Section of the National Safety Council was held.

The Committee on Mine Ventilation held its first meeting at which it discussed ways of attaining the purposes for which it was formed. Special luncheons and dinners were held by the Mining Methods Committee, which was followed by a general conference; Milling Methods Committee, Industrial Relations Committee, Iron and Steel Committee, and the Institute of Metals Division.

At the aimual business meeting on Feb. 17, the following ticket was elected, and the reports of the President, Treasurer, and Secretary were presented:

J. V. W. Bynders, Director and President; John L. Agnew, Director and Vice- President; Ralph H. Sweetser, Director and Vice-President; Sydney H. Ball, Director; George D. Barron, Director; William H. Bassett, Director; J. M. Callow, Director; Charles F. Rand, Director.

E. De Golyer was elected First Vice-President; Charles F. Rand, Treasurer; Frederick F. Sharpless, Secretary; and Percy E. Barbour, Assistant Secretary, at the meeting of the Directors on Tuesday evening.

The Local Sections representatives met at 10 o'clock on Wednesday morning for the ustial exchange of views regarding local section activities.

NEW YORK MEETING, 1926 XXXix

This meeting has become increasingly interesting and this year an extra session was held immediately after luncheon.

As usual a buffet luncheon was served each noon at the Institute Headquarters, members of the Woman's Auxiliary participating; these luncheons also were more largely attended so that the capacity of the fifth floor was severely taxed. Special luncheons and dinners were held by the Mining Methods Committee, Milling Methods Committee, Industrial Relations Committee, and the Institute of Metals Division.

On Monday afternoon a bronze tablet of Dr. Rossiter W. Raymond was unveiled in the lobby of the Engineering Societies Building, with appropriate ceremony.

The Annual Smoke was held in the Caf6 Savarin, in the Pershing Building, on Monday evening. On Tuesday evening there was the usual informal dance at Institute Headquarters.

There were 727 guests at the Annual Banquet at the Waldorf, on Feb. 18, making this the largest banquet given at an Institute annual meeting. W. L. Saunders was toastmaster. B. B. Thayer, Chairman of the James Douglas Medal Committee, presented the name of William H. Bassett for the 1925 award of the James Douglas gold medal, and J. V. W. Re 3 myers, President of the Institute, presented the medal and diploma. Addresses were made by William Kelly, retiring President; Hon. Charles McCrea, Minister of Mines for the Province of Ontario, Canada; Maj.-Gen. Charles P. Summerall, Commanding Second Corps Area, which includes New York; and J. V. W. Reynders, the new President.

On Thursday, more than 300 members and guests went by special train to the Naval Air Station at Lakehurst, N. J. Naval oflScers were in attendance to explain the station and ships. A luncheon was served in the Air Station theater, following which Dr. R. B. Moore gave a brief talk on helium, its method of recovery, and repurification.

On Friday, at the invitation of President C. W. Nichols, the nonferrous metallurgical group visited the metallurgical plant of the Nichols Copper Co. at Laurel Hill, L. I. After examining the plant the members were entertained at luncheon by the plant officials.

The Woman's Auxiliary had its usually very full and interesting program for each day of the meeting.

Technical Sessions Institute of Metals Division George K. Elliott, Chairman

New Developments in High-strength Aluminum Alloys. Robert S. Archer and Zat Jeffries.

Etching Aluminum and Its Alloys for Macroscopic and Microscopic Examination. Fulton B. Flick.

xl NEW YOKK MEETING, 1925

Scratch and Brinell Hardness of Severely Cold-rolled Metals. M. F. Fooler and E. J. QtriNN.

Eutectic Patterns in Metallic Alloys. C. H. Green.

Wm. M. Corse, Chairman

X-Ray Evidence versus the Amorphous Metal Hypothesis. Robert J. Anderson. and John T. Norton.

The Malleability of Nickel. Paul D. Merica and R. G. Waltenberg. Recrystallization and Grain Growth in Soft Metals. Maurice Cook and Ulick R. Evans.

Determination of Structural Composition of Alloys by a Metallographic Planimeter. E. P. POLUSHKIN.

George C. Stone Chairman

Corrosion of Copper Alloys in Sea Water. William H. Bassett and C. H. Davis. Tantalum, Tungsten and Molybdenum. E. W. Engle.

Coal and Coke Sy mposium

David White, Chairman

Environmental Conditions of Deposition of Coal . David White .

Microscopical Constitution of Coal. Reinhardt Thiessen.

Microstructure of Coal. Clarence A. Seyler.

Microscopical Structure of Anthracite. Homer G. Turner.

Coal in Relation to Coke. Edward C. Jeffrey.

The Resolution of Coal by Oxidation. W. Francis and R. V. Wheeler.

Constitution of Coal. F. V. Tideswell and R. V. Wheeler.

Organic Sulfur Compounds in Coal. J. Jolly and R. V. Wheeler.

Selective Combustion in Coal. F. S. Sinnatt.

Nitrogenous Constituents of Coal. John W. Cobb.

Coal and Oxygen. Samuel Wilson Parr and F. B. Hobart.

A Modern View of the Chemistry of Coals of Different Ranks as Agglomerates. Arno Carl Fieldner and J. D. Davis.

Contact Metamorphism of Some Colorado Coals by Intrusives. J. Brian Eby. The Progressive Regional Carbonization of Coal. David White,

Moisture as a Component of Volatile Matter of Coal. William Taylor Thom, Jr.

Petroleum

E. De Golyer, Chairman

Conservation of Oil. Henry L. Doherty.

World Production of Petroleum in 1924. E. Db Golyer.

Bearing of Price on Oil Reserves. J oseph E. Pogue.

Ratio of Peak Production to Estimated Total Production in Certain Oil Fields. G. B. Richardson.

First Test of the Clinton Oil Sand in West Virginia. David B. Reger.

Value of Aerial Photographic Surveying and Mapping to Petroleum Companies. H. Case Willcox.

NEW YOBK MEETING, 1925 xli

Aerial Photographic Maps. Gbrabd H. Matthes.

Development during 1924 in:

Pennsylvania and New York. Meredith E. Johnson.

West Virginia. David B. Reger.

Ohio. J. A. Bownocker.

Kentucky and Tennessee. Wilbur A. Nelson.

Indiana. W. N. Logan.

Illinois. G. F. Moulton.

Gulf Coast. David Donoghue.

Texas Outside of the Gulf Coast District. F. H. Lahee.

Oklahoma. R. S. McFarland.

Kansas. Everett Carpenter.

Montana. Max Bauer.

Wyoming. E. L. Estabrook.

Colorado. C. H. Wegemann.

Mexico. Valentin R. Garfias and R. V. Whetsel.

Venezuela. Edwin B. Hopkins and H. J. Wasson.

Peru. V. F. Marsters.

Colombia. L. G. Huntlet.

France. P. Martignan.

Poland. Leon Orlowski.

Rumania. George Anagnostache.

Canada. G. S. Hume.

Russia. A. Beeby Thompson.

Cuba. Ralph Arnold.

The Jurassic as a Source of Oil in Western Cuba. Albert Wright, Jr., and P. W. K. Sweet.

Increasing Production of Petroleum by Increasing Diameter of Wells. Lester C. Uren.

Significance of Fluid Level in Oil Well Pumping. Lester C. Uren.

Mining Methods — Metal

R. M. Raymond, Chairman

Methods of Mining and Ore Estimation at Lucky Tiger Mine, Sonora, Mexico. R. T. Mishler and L. R. Budrow.

Mining Methods of Jarbidge District, Nevada. John Park.

Mining Methods at Cornucopia, Oregon. Robert M. Betts.

Mining Methods in Zaruma District, Ecuador. Rudolph M. Emmel.

Mining Methods at the Homestake. A. J. M. Ross and R. G. Wayland.

Mining Methods — Coal

Thomas H. Clagett, Chairman

Systems of Coal Mining in Western Washington. Simon H. Ash.

Method of Mining a Steeply Pitching Anthracite Vein by Successive Skips. J. S. Miller.

Simultaneous First and Second Mining on Steep Pitches. Dever C. Ashmead. New Orient, an Unusual Coal Mine. George B. Harrington.

Properties of Liquid Oxygen Explosives. G. St. J. Perrott.

New York Meeting, 1925

Coal

C. M. Lingle, Chairman

Ultimate Recovery from Anthracite Beds. Henry H. Otto.

Schedule Rating Coal Mines in Pennsylvemia for Compensation Insurance Rates. Rush N. Hobleb.

Application of Gaussian Curves to Mining Industry. Hugh Archbald.

Joint Meeting Coal and Petroleum

S. A. Taylor, Chairman

Safeguarding Coal Mining Operations against Danger from Oil and Gas Wells. A. W. Hesse.

Belt Conveying of Coal, H. C. Frick Coke Co. Mines. Illustrated with Motion Pictures. Thomas W. Dawson.

Analysis of the Performance of the Coal Jig. H. F. Yancey and Thomas Fraser.

Ground Movement and Subsidence

Louis S. Cates, Chairman

Factors Affecting Bank Slopes in Steam-shovel Operations. Louis S. Cates.

Mine Support and Mine Subsidence in the Birmingham Districts. W. R. Crane. Rock Bursts and Bumps. George S. Rice.

Nonmetallic Minerals

Heinrich Ries, Chairman

Limestone Production as a Mining Problem. J. R. Thobnen.

Engineering in Limestone Production. C. C. Griggs.

Manufacturing Problems of Cement Industry. John J. Porter.

Rotary Calciners for Gypsum. Frank A. Wilder.

Phosphate Deposits of Idaho and Their Relation to the World Supply. VIrgil R. R. Kirkham.

Milling Methods

Charles E. Locke, Chairman

Recent Developments in Fine Grinding and Treatment of Witwatersrand Ores.

Carl R. Davis, J. L. Willey, and S. E. T. Ewing.

Determination of Dissolved Oxygen in Cyanide Solutions. A. J. Weinig and Max W. Bowen.

Precipitation Efficiency of Zinc Dust in Cyanide Process. Robert Lepsoe.

Studies on the Precipitation of Gold and Silver on Charcoal from Cyanide Solution. John Gross and J. Walter Scott.

Non-ferrous Metallurgy

E. P. Mathewson, Chairman

Redistillation of Zinc. Kurt Stock.

High Zinc in Lead Blast Furnace Slags. Fred E. Beasley

NEW TOEK MEETING, 1925 xliii

A New Roasting Furnace for Zinc Flotation Concentrate. Chables H. Fulton and J. Bubnb Read.

Application of Pulverized Coal to Copper Refinery Furnaces. E. W. Steele.

Recovery of Arsenic and Other Valuable Constituents from Speiss. C. P. Linvillb.

Iron and Steel

R. H. SwEETSEB, Chairman

Manganiferous Iron Ores of Cuyuna District, Minnesota. Carl Zapffe.

Economics of the Cu3runa Manganiferous Iron Ores. C. P. McCormack.

Probable Error in Blast Furnace Records and Calculations Therefrom. T. T. Read. Reduction of Iron Ores by Carbon Monoxide. Heihachi Kamura.

Effect of Sulfur on Blast Furnace Process. T. L. Joseph.

Albert Sauveur, Chairman

Chemical Equilibria during Solidification and Cooling of White Cast Iron. H. A.

Schwartz and (Mrs.) Anna Nicholson Hird.

Some Factors Affecting the Elimination of Sulfur in the Basic Open Hearth Process.

C. H. Herty, Jr., A. R. Belyea, E. H. Burkart, and C. C. Miller.

Finishing Melting Temperatures of Simple Ingot Steels. Henry D. Hibbard.

The Reaction between Manganese and Iron Sulfide. C. H. Herty, Jr. and 0. S. True.

Brief History of Metallurgical Practice in Cannon Making with Particular Reference to the Cast Iron Gun. Job Goostray, R. F. Harrington, and M. A. Hosmer.

Joint Session with the Mining Section of the National Safety Council

Prevention of Coal-dust Explosions

Benjamin F. Tillbon, Chairman

Review of Coal Dust Investigations. George S. Rice.

Economics of Rock Dusting Bituminous Coal Mines. Edward Steidle. Determination of Suspensoids by Alternating Current Precipitators. Philip Drinker, andR. M. Thomson.

Value of Humidifying Methods in Explosion Prevention in Coal Mines. Daniel Harrington.

American Recommended Practice for Rock Dusting Specifications: Report of Subcommittee of the Mining Correlating Committee on Rock Dusting. E. A. Holbrook.

Silicosis and Its Prevention, Illustrated with the film, "The Dust That Kills." R. R. Sayers.

Joint Session with National Safety Council and Mining and Metallurgical Society of America: under the Auspices of Industrial Relations Committee

R. M. Catlin, Chairman

Maintaining Interest in Safety. C. B. Auel.

Essential Factors of Industrial Relations. C. F. Dietz.

Papers

ENVIRONMENTAIi CONDITIONS OF DEPOSITION OP COAL

Environmental Conditions of Deposition of Goal

By David White, D.S.,* Washington, D. C.

(New York Meeting, February, 1925)

The environmental conditions under which coals are deposited are revealed by the stratigraphy of the coal basins and coal beds and by the details of the structure and the physical constitution of the coals themselves.

The Land Surface Generally Low Relief or Base Level

In the Paleozoic coal fields, which have longest been worked, are most important, and are best known, we find relations, in general, as follows: A post-Mississippian uplift with, in most cases, very moderate deformation, followed by erosion by which the uplifted regions, especially the bolder of the new topography, were largely worn down, while the older and less deformed regions were more or less extensively base leveled. Base leveling of most of the region continued as the deposition of coal measures proceeded. Consequently, in most coal fields the Pennsylvanian, or upper Carboniferous, lies unconformably on the Mississippian or on older formations. There are but few regions in which sedimentation is seen to have been apparently continuous from the Mississippian into the Pennsylvanian "Coal Measures."

Aas of Greatest Sisidence Flanks Axis of Upwarp

In most regions the initial deposition of " Coal Measures " took place in a narrow trough lying at the foot of and parallel to an axis of post- Mississippian uplift. The early "Coal Measures" deposits consist largely of sand with conglomerate, sometimes in great amounts, derived from the upwarping area. Generally, only fresh- or brackish-water deposits are found over the greater part of these initial basins, most of which are in the form of long narrow estuaries, or elongated fluviatile and lacustrine basins.

Expansion of Early Basins

In every case, there is evidence of filling of the early narrow basin, with lateral extension of the area of sedimentation; but it is to be noticed

♦Senior Geologist, U. S. Geological Survey.

Environmental Conditions Op Deposition Op Coal

that the encroachment was relatively restricted on the side toward the uplifting axiS; though this is the side of deposition in greatest thickness, both because most of the clastic sedimentary material was derived from this side and because the greatest subsidence or depression of the trough occurred here. Meanwhile the axial land mass itself was in most cases uplifted in intermittent or irregular movements of slight or minor magnitude. On the opposite side of the basin, the surface of the ''Coal Measures" sediments extended farther and farther inward over the opposite lowland coast. Thus, a broadening area, including as its eccentric focus the initial basin, was subsiding and being filled, usually with some warping of the underlying land mass, as the area of sedimentation encroached farther and farther on the base-leveled region of the continental mass, or across the lowlands and marshes of the fresh-water basin. Normally, this continued until toward the close of coal-measures deposition, when incipient deformation took place, with the development of new areas of uplift and restriction of the areas of sedimentation — movements that, in most cases, were more or less unfavorable for the deposition of coals. The movements appear to have been isostatic.

The progressive steps in the development of the typical "Coal Measures" basin just outlined are seen in most European as well as in American coal fields. In the Appalachian region, the comparatively narrow trough of early Pennsylvanian (lower Pottsville) deposition lies at the eastern margin, including the Coosa and Cahaba basins in Alabama. The easternmost tip of the Pocahontas region is dipping down from the west into the basin, while Pottsville, Pennsylvania, is apparently well down toward the bottom on the western slope of the early trough. Likewise, in the mid-continent region, the earliest "Coal Measures" of Texas flank the Llanorian uplift, on the east, and the tremendous thickness of Pennsylvanian in Arkansas and Oklahoma lies in the early Ouachita axis on the north of Llanoria. Here the early "Coal Measures" deposition gradually encroached farther to the north and, in late Pottsville time, a comparatively narrow estuary or valley extended from the region embracing Vinita and Bartlesville, Okla., northeastward across southeastern Kansas and northwestern Missouri into Iowa, where it apparently shoaled out broadly. The deposits of latest Pottsville age embracing the Bartlesville oil sands in this basin, were probably derived from the now buried Nemaha Mountains. The Paleozoic coals of the Rocky Mountain region were similarly laid down along the flanks of the post-Mississippian uplifts.

Unstable Levd

The great variability in the composition of the "Coal Measures" sediments, which range from coals, fine silts, and limestones through sandy shales, shaly sandstones, and sandstone to coarse conglomerates, which often seem irregularly distributed in the vertical column, reflects

David White

and proves the instability of the continental region in which they were laid down and, in particular of the land mass whence the sediments of terrestrial origin were largely derived. The occasional presence of limestones and other deposits carrying marine fossils, which occur here and there between other beds carrying brackish- or even fresh-water fossils, unmistakably proves either fluctuation of the sea level (that is, rising and falling of the land), or exclusion of the sea at times as the result of tilting of the regions or the formation of barriers. Generally it is the former. Both causes have operated in different regions and, at different times, in the same region. It is, however, to be noted that the seas which invaded the early narrow estuaries or spread out over the broad flood plains and base-leveled regions were never deep. Probably, in most of our large coal fields the surface of sedimentation seldom or never lay as much as 200 ft. below tide level, and then only for intervals. Much of the time, on the other hand (at least during the times of deposition of coals of commercial purity) the sea was excluded from the region of coal formation.

Contemporaneous Erosion Common

Under the conditions prevailing, the occasional erosion of newly formed sandstones, shales, or coals in consequence of exposure or slight local or regional deformation was normal, as also were the consequent local unconformities and the deposition of heavy outwash sandstones or conglomerates as the result of elevation of the sources of supply and acceleration of the drainage flowing into the basin. It was under precisely such conditions that the Mahoning sandstone, which over considerable areas is somewhat conglomeratic, was laid down; the Homewood sandstone, which marked a change in the elevation of the shore regions as well as slight differential movement in the interior of the basin; or the Sharon conglomerate, the Raleigh sandstone, etc. The Raleigh sandstone, which lies at the base of the middle Pottsville, is restricted to a relatively narrow zone in and bordering the axial basin of early Pottsville deposition. Analogous conditions prevail in the mid-continent and southwestern regions.

Invasions of the Sea

Most, if not all of the limestones of the lower Conemaugh and older Pennsylvanian formations of the Appalachian trough, and apparently all of the limestones in the interior and western ''Coal Measures" basins are definitely marine, though many of them bear evidence of having been laid down nearly up to tide level, with very shallow covering of water. This is proved by wave and ripple effects, by the earthy material included in many of them, by the character of their contacts, by the occasional presence of vascular plants rooted in hollows and crevices, and, very rarely, by the development of soils that in some places lie immedi-

Envibonuental Conditions Of Deposition Op Coal

atdy on the surface of the thin limestones, as is described by Hinds and Green. Some of the thin earthy limestones are mud-cracked. Sometimes the transition from the marine bed, especially a limestone bed, to the Stigmaiia underclay is abrupt; more often shales and sandstones intervene. Frequently, the "underclay" beneath the coal lies on sandstone, though prevailingly it lies on shales. Very rarely it lies, with slight intercalation of carbonaceous mud, on another coal.

The Swamp Environment

Freshwater Swamps the Site of Ordinary (TToody) Coal Formation

The typical Stigmaria clay that almost invariably imderlies the Paleozoic coal is familiar alike to the engineer and geologist, who usually style it erroneously as fireclay. The innumerable rootlets and the larger roots of Stigmaria are nearly always conspicuous or may be readily found in these clays though, on account of lack of close attention, the obvious evidence of growth in place is not so commonly noted. The miners are apt to identify the larger roots as "snakes," in which case, naturally, rootlets and growth in place are not looked for.

Old Soils under Coal Beds

Careful observation of the vmderclays beneath different coals and in different regions shows not only that the Stigmarise are generally in place of growth, but that the underclays occasionally embrace debris of land plants that have become covered in the course of deposition. Roots of ferns or cycadofilic trunks, also in place of growth, are common and, where sandy, Calamarian types; for the Calamarian group always grew in wet soil, some of the types favoring wet sands, just as do most of the living Equiseta of the present day.

The building up of the imderclay by further sedimentation under a very thin, and, probably fluctuating, water cover often took place, in which cases root systems developed at successively higher levels from the larger plants, as was shown by Grand'Eury.* Marine fossils are not found in the typical underclay and even brackish-water fossils are practically unknown except in very rare occurrences of carbonaceous "slate" or somewhat bony black stuff between the pure coal and the underclay.

The typical imderclay is now known to be an old soil formed in a swamp. Its upper portion, at least, is non-marine and non-brackish; it is terrestrial and was, at times, subaerial; that is, exposed land.

H. Hinds and F. C. Green: The Pennsylvanian of Missouri: Report Missouri Bur. of Mines and Geol. (1915).

J. J. Stephenson: Proc. Amer. Phil. Soc. (1916) 21; (1917) 63; (1918) 1.

F. C. Grand'Eury: Recherches Gfobotaniques sur les Forets et &ls Fossiles, etc., pts. I-III (1912-1914).

David White

Water in Swamps

The nearly omnipresent Stigmarisa are the rhizomes and roots of different types of the giant Paleozoic lycopods of the groups Sigillaria, Lepidodendron Bothrodendron, Lepidophloios, etc., which were the dominant trees of the Carboniferous swamp forests. These trees were adapted to growing in swamps in which a shallow cover of water was normally present, very much as in our southern Atlantic coast swamps, during the larger part, at least, of the year. The roots, by their spread near the surface, their organization or structure, and the characters of their rootlets, such as air chambers and the absence of root hairs, were adapted to growing flatwise near the surface of the mud in a wet swamp. Some of the Stigmarise had knees similar in development and disposition to those seen in the bald cypress growing in the water-covered swamps of our Southern States. Both knees and tricks were provided with hydathodes and pneumatophores to regulate water content and furnish air supply to the roots. Further, the bases of the of the common Sigillaria and Lepidodendron were dilated abruptly for two or three feet above the roots and were provided with special structural features, just as are the gums and cypress trunks occurring in the watercovered swamps of the present time. The dilations mark the ordinary water level in the swamp. These features have been strikingly illustrated by Potonie. The rootlets of the fern trunk contained gum canals, and the Calamarian roots had air spaces; all indicative of an aqueous habitat.

Most of the giant lycopods of the early and middle 'Coal Measures' were heterosporous; that is, they bore two types of spores, one large and one small, of different sexes. These spores, as will be pointed out later, were provided with thick resinoid or waxy-resinous outer envelopes (exiles) to prevent decay in water, and the perpetuation of the species was largely dependent on the water cover of the swamp to drift megaspore and microspore into conjunction.

In fact, it will be seen that when, due to climatic changes, the persistence of the water cover in the swamps became too imcertain the giant lycopods waned and soon disappeared, other types of trees, verging into the orders of coniferous gymnosperms, and giant tree ferns taking their places.

Swamps Generally Forest Covered

The typical coal bed, of commercial purity, laminated and of wide extent, is only a compressed, reduced, lithified, and more or less altered peat. Not only is it a swamp deposit, as illustrated by Doctor Thiessen,*

D. White: The Carbonaceous Sediments; in Treatise on Sedimentation, by W. H. Twenhofel and others; MS. is in hands of editor.

H. Potonie: Entstehung der Steinkohle (1920) 6th ed., 118, 188.

Miorosoopioal Constitution of coal; see p. 35.

ENVIROiaiENTAL CONDmONS OF DEPOSITION OF COAL

but it is distinctly a fresh-water swamp deposit. Both the plants from whose debris the coal is formed as shown by the microscopical study of the fuels, and the fossil plants associated with the coal beds (those found in the shales or sandstones immediately overlying the coal and those present in the clay partings within the coal bed itself) are land plants, vascular, and more or less woody in composition, belonging to the Pteridophytes and higher orders of plant life. In general, they grew on or near the spot where their debris is foxmd. Those accompanying and composing the coal in the exclusively fresh-water basin are indistinguishable from those accompanying coals not only in the fresh-water zones of formations carrying marine horizons, but even in measures where the underclays and overlying coals are intercalated in series distinctly marine; as in Missouri where, extremely rarely, limestones lie immediately beneath the imderclay, and marine fossils mingle with fossil-plant debris in the roof shales. Similar relations between the coal and fossiliferous marine beds may be foimd locally at the level of the Ames limestone or in the Mercer shale in western Pennsylvania.

Plants Forming Ordinary Coals Not Halophytic

The typical coal-forming vegetation did not and could not live in salt or brackish water. No vascular plant forms have yet been recognized as distinctive of the coal deposits laid down in areas of proximity to sea level, like the Eastern Interior coal field where temporary subsidence of the land or the breaching of bars, such as invariably characterize the borders of a subsiding base level coast, so often permitted the sea to overwhelm and kill the coal-forming swamp vegetation. The features of the underclay, the plants forming the coals, the bedding and even the lamination of the coals reveal no appreciable or essential distinction between the coals of the distinctly fresh-water basins and those laid down in the great lowland swamps of areas like the Illinois-Indiana and the Missouri-Kansas fields, where proximity to sea level and instability of land elevation permitted the exposure of great expanses of sea bottom, and the development thereon of swamps and land floras. The deposition of coals was usually followed by some thickness of non-marine shales and sandstones, before a too rapid rate of subsidence again made possible the reinvasion of salt or brackish water over the coal-forming swamps. So far as I have been able to learn, coals (peats) of ordinary woody type and of commercial purity and of great horizontal extent are not now being laid down in brackish or salt water in any part of the world.

Saltrwater Invasions of the Swamps

In some regions, salt-water invasions occurred in the midst of coal formation (peat deposition) in portions of the tide-level swamps of Missouri and Illinois, as is shown by the presence of debris of marine mollusks

David White

in thin partings occurring locally within the coal beds. Not infrequently, also, one may observe the presence of roots of land plants that grew in place in the marine muds of the partings, as in most cases these invasions may have resulted from breaching of barrier beaches. I have, in earlier papers, emphasized the part played by such barriers in some of the tidelevel coal fields like those of the mid-continent and interior areas, and the probable effectiveness of the dense vegetable growth in obstructing the progress of salt water into the swamp. In other cases, it is likely that the advance of salt water would be checked also by low gradients of the swamp as it spread across the somewhat uneven surface. Irregularity of this surface is, in many instances, indicated by the varying floor and thickness and bedding of the coal beds.

Muck in Coals

In the Illinois and Indiana coal fields, some of the coals, especially Nos. 3, 5, and 6, are covered, over large areas at least, by mucky carbonaceous material more or less laminated and frequently marked by very thin intercalations — sometimes mere films — of inwashed sand. Here, the surface of the peat swamp has been partly oxidized after denudation of its vegetal cover, and some of the peaty substance, reduced to muck, has been relaid imder wave action with thin washes of sand. Marine fossils occur here and there in these deposits, in which delicate parts of plants, such as fern leaves, are generally wanting; due probably to attrition, slowness or instability of deposition, and the greater opportunities for oxidation.

Rise of Water Level

In any coal bed, the principal changes in structure and constitution are due to changes in the water level. In most regions, rise of the water level ran more or less nearly parallel to the growth in thickness of the peat deposit; for bituminous coals as much as 6 or 7 ft. thick this thiclmess must originally have been over 40 or 60 ft. This predicates a gradual sinking of the tide-level swamps as the surface of the peat was built up, and explains how readily a slightly too rapid subsidence, with or without consequent breaching of barrier sands, might permit salt-water invasion and, with continuous subsidence, the coals could be overlain by marine muds, shales, or limestones. Elevation of some part of the higher land or the receipt of larger contributions from some sand-lain area, might cause the deposition of sandstone. Filling the basin caused readjustment of the surface of sedimentation; and, if the water level rose too little, even as raised by the peat itself, vegetal accumulation suffered more advanced decay and peat formation was slower or its growth was arrested.®

' D. White and R. Thiessen : Bur. of Mines BM. 38 (1913) 62.

D. White: The Carbonaceous Sediments (1923),

Environmental Conditions Op Deposition Op Coal

Sulfur and Silieification

In earlier papers, I have emphasized the generally far greater amounts of sulfides in the tide-level basins, a relation that is quite generally recognized, though the assumption that the larger sulfur supply has to do with the sulfur of the marine animal life rather than with reactions in the salts of the marine or brackish waters impregnating beds not far distant above or below the coal invites more thorough consideration by the chemist.

In the fresh-water basin, which is fluviatile or shallowly lacustrine, the interruption of peat formation by too deep inundation, with more or less extensive in washing of silts, sand, etc., thus buying the peat deposits, affords conditions much more favorable for the preservation of the remains of the land vegetation growing on the swamp. The flora is overwhelmed and buried or slowly drowned out while sedimentation is in progress, instead of being exterminated by the salinity of encroaching sea water.

The apparently sudden segregative precipitation of colloidal silica at or close to the surface of the organic deposits, so as to form siliceous nodules or to cause the partial impregnation of logs, stems, fruits, etc., is, in most cases at least, almost certainly due to rapid invasions of saline or brackish water. With the siliceous segregations, pyrite or marcasite is apt to occur. This explanation is consistent with the occurrence of such nodules and impregnations in what we commonly call marine coal measures basins, like those of the interior and mid-continent regions — that is, in the tide-level swamps. The impregnation of the vegetation by silica or lime occurred unmistakably at the time of, or very soon after, deposition.

Similar Conditions in Mesozoic and Tertiary Coal Fields

The depositional relations of the Mesozoic and Tertiary coal fields of the western United States were, in general, evidently similar to those of the Paleozoic areas with respect to the topography. Most of the western basins were far less extensive than the eastern Paleozoic lowlands, and some of them appear to have been relatively restricted, but the coals were nevertheless laid down in lowlands and marginal swamps that crept upward on a gradient too low to permit drainage under the climatic conditions prevailing, and whose level was raised and broadened by growth of peat and rise of the water level.

The coal measures were deposited in fresh-water basins, in estuaries, and in broad coastal swamps generally bordering epicontinental seas. Shifting of shore lines or accentuation of erosion, presumably consequent to uplift or deformation of the source regions of the arenaceous sediments, is recorded in the wedge shapes or lenticularity oi the sandstones and the tongue characters of those coal measures groups, which represent conti-

David White

nental deposits fingering into the marine sediments of the epicontinental sea. This is particularly true of the Cretaceous coal measures of the Mesaverde in Montana, Wyoming, Colorado, and New Mexico.

Examination of the floras of the coal beds in the principal western coal fields nearly everywhere discloses the existence of old soils with roots beneath the coal beds. The roots, which are clearly seen to be in position of growth, are rather more varied in botanical range than in the Paleozoic, where Stigmaria is so omnipresent. In some areas shallow basins, lakes, or ponds evidently were in process of filling imtil land vegetation was able gradually to spread out from the edges so as to cover the surface, which eventually was forested exactly as is to be seen in many peat swamps at the present time. In these cases, carbonaceous muds and shales underlie the purer, well-bedded, laminated coals, which in general are characteristically' woody. The occasional influx of oversweeping and aggrading muds and sands, burying the swamps so as to cause partings in the coal beds or even the total suspension of coal deposition for considerable time, harmonizes with the now more generally recognized instability of the continental masses and the generally fluviatile sedimentation of the fresh-water basins in which, however, lakes unmistakably were present.

Climatic Conditions of Coal Fokmation

The study of both the structures of the coal bed and the microscopical constitution of the coal itself confirms the evidence of the stratigraphy and the sedimentation of the enveloping strata in proof that the coals of the normal types (whether lignite, bituminous, subbituminous, or anthracite) were laid down as peats, most of the deposits of co mm on type having been formed in forested swamps of great extent. As at the present time, the environment of peat formation varied somewhat, but the ordinary woody coals were certainly laid down on broad coastal plain or inland swamps covered more or less of the time by water, which during peat deposition, however, was not so deep as permanently to interrupt the growth of arborescent vegetation.

Sunlight and Wind

Comparison of the structural features of the coal-forming vegetation of the Tertiary and Upper Cretaceous with moist lowland and swamp trees, shrubs, and ferns of the present day leaves no room for doubt that the overhead conditions as to sunlight and clouds, with wind, were in general comparable to those of the moderately humid and very humid regions of the earth at the present time. The immediate ancestors of the bald cypress were present in most Tertiary coal swamps. Winged seeds indicating dispersing winds were common.

Environmental Conditions Op Deposition Op Coal

The features of the vegetation that grew in the Paleozoic swamps similarly indicate sunlight, probably in moderate amount, while ripple marks and, in some cases, fairly well-developed wave marks in the coal measures strata bear testimony as to winds. Many of the Carboniferous seeds and fruits were provided with wings to assist in distribution.

Rainfall and Temperature

An inspection of the evidence as to humidity and rainfall shows some variation, not only from region to region, but from period to period in the same regions. The deposition of Paleozoic peat in the enormous thicknesses required to form workable coal beds, as the deposits are now reduced, calls for a climate more or less distinctly humid or even wet. In most regions, the rainfall was either moderately heavy and well distributed through the year or it was copious through the greater part of the year.

Lower Pennsylvanian

In the Pottsville coal measures of North America and in the Westphalian series of Europe, which is nearly equivalent in age, the evidence clearly points toward abundant rainfall relatively well distributed throughout the year. General humidity, as well as mildness of temperature, is shown by the rapid and large growth of the lush vegetation. The Pottsville and lower Alleghany plants, in particular, had large and comparatively thin-walled cells with large intercellular spaces. The digestive tissue of the leaves was conspicuously lacunose, and provision was made for discharge of excess of water content of many of the plants. The lycopods and Calamariae, the latter being related to the living horsetails, were gigantic and the ferns and femlike cycadofilic types were mostly very large or greatly elongated. The pose of branches and leaves and the leaf forms suggest the shedding of rain. Most of the femlike types of the genus Sphenopteris, especially those included by Stur in his genus Diplothmema, were long clambering plants, probably climbing on to or over the more robust types, such as Neuropteris and Alethopteris, which were themselves small trees, the trunks of which attained in some cases a diameter of nearly two feet. Many of these chambering or climbing plants of the Pottsville, and particularly the New River and the Kanawha divisions of the Pottsville, had very delicate, even membranaceous, foliage — filmy, and often deeply dissected. Rhacophyllum, by its

E. Carthaus: Die Klimatischen VerhSJtnisse der geologischen Vorzeit von Pracambrium bis zur Jetztzeit, 1910; A. G. Seward: Climate as Tested by Fossil Plants, 1914; A. G. Nathorst: Smithsonian Report, 1911; W. Gothan: Die Jahresringldsigkeit der pklaozoischen Baiime, 1911; P. Bertrand: Ann. Soc. G6ol. Nord, (1909) 88, 92; C. Schuchert: Smithsonian Report, 1914; H. Carpentier: Les plantes fossiles. Rev. G4n. Bot., 1922; D. White: Bur. of Mines BtUL 38 (1913), and The Carbonaceous Sediments.

David White

habit, and some of the ferns, by the distribution of their nearest living relatives, are connected with warm climate floras. At this time, the forests of the American and western European coal fields were truly subtropical or tropical in aspect. A very mild, or, at least, subtropical, temperature is shown not only by the enormously rapid growth and the delicacy of the femlike lianas, but it is indicated further by the absence, or only very slight development, of rings of annual growth. Growth of plants during these periods appears to have been almost free from interruption and certainly free from severe winter frosts in temperate latitudes.

Some instability of the water level in the swamps is shown by the bedding and lamination, including the layering of mother of coal,' to which reference will later be made, but the general maintenance of a thin water cover over the surface of the swamps during the great part, at least, of the year is shown by the dilation of the basal 2 or 23 ft. of the butts of many of the trees, and by the presence of knees, by pneumatophores, etc. Many of the seeds and fruits were provided with air chambers to aid flotation. Closure of pollen chambers prevented entrance of water pending delayed pollination of the ovules in some of the genera. Reference has already been made to the prevalence in this period of heterosporous lycopods, the continuation of whose species required an aquatic environment in which the megaspores and microspores might drift into conjunction. Low herbaceous types seem to have been exceedingly rare. Mosses are almost unknown.

Upper Pennsylvanian Time

In the upper Pennsylvanian, which includes the upper Alleghany, the Conemaugh, and the Monongahela coal measures in America and the Stephanian of Europe, the climate appears to have been less uniform. The rainfall was apparently less evenly distributed through the year and the humid subtropical or tropical lianas are less in evidence. This is particularly true of the Appalachian coal fields, where tree ferns are far more numerous and varied. The changes may be connected with the causes of the introduction of red beds deposition in this region. In the tree ferns and in some of the lycopods, we have immensely thickened bark (including internal ramenta) with structural physiological provision for water storage, presumably to tide over seasons of reduced rainfall. The probable occurrence of dry seasons is further shown by the rapid disappearance of the heterosporous lycopods, whose dominance called for a greater persistence of the water cover in the swamps. Most of the membranaceous types had disappeared or were disappearing. The cycadofilics had larger pinnules and lobes, and the leaflets of the Pecopteiids and other tree ferns were prevailingly not only rather thick but more or less villous. The ecological characteristics were accordingly comparable

D. White: Bur. of Mines Butt. 38 (1913) 74.

Environmental Conditions Op Deposition Op Coal

to a subtropical or mild tropical dense plant growth with abimdant tree ferns all adapted to a short dry season, although the total rainfall was relatively large. Ample precipitation or water cover is, however, requisite for peat formation in tropical regions.

Consistent with the postulated conditions, wood growth appears to have been rather less rapid than in the earlier coal measures, and the cells are generally rather thicker, and, what is more significant, the wood in some of the t 3 rpes has more or less well-developed annual rings. The general character of the vegetation, which included many genera whose present-day representatives are distinctly tropical or subtropical, justifies the conclusion that the growth rings, which neither in western Europe nor in eastern America are as well defined as in the regions of present-day winter frosts, probably reflect merely the interruption of growth by dry seasons rather than by severe winter freezing.

Permian Climate

Seasonal changes are still more evident in the Permian deposits — even those laid down in the generally moist regions of coal formation. Fluctuation in rainfall is fairly evident and, outside of coal field areas, xerophytic plants are not rare. In the United States, the evidence as to alternating wet and dry seasons in the Permian may be regarded as conclusive. Small wood cells and well-developed annual rings may indicate seasonal variations in temperature also. Coal formation was greatly reduced in the Permian swamps and, during upper Permian time, was nearly unknown except in a few parts of the world.

Coincident with, and probably in consequence of, seasonal diversity in the latest Pennsylvanian and Permian, which are periods of extensive red beds deposition in America, there took place a differential evolution of the g 3 nnnosperms, with the development of plants closely resembling, if not indistinguishable from, cycads, and of coniferous types closely allied and probably lineally ancestral to the modern Araucaria and the Gingko. The AraucariaB are now reduced to a few species, while Gingko is perhaps technically extinct, it having been preserved by cultivation under religious auspices. This was the period of development of the gymnospermous seed with capacity for surviving one or more seasons unfavorable for germination.

Notwithstanding the evidence for seasonal changes, the writer has not been able to recognize in the Permo-carboniferous swamp floras, either of the United States or in western Europe, proof of severe freezing or seasons of actual winter of such severity as is characteristic of the region embracing Baltimore, Cincinnati, and St. Louis at the present day, although early Permian time witnessed extensive glaciation, even in the tropics, in India and at low altitudes in temperate regions of Australia, south Africa, and Brazil.

"D. White: Jfd. Geol (1907) 15, 615.

David White

Climate of Mesozoic and Tertiary Coal Fields

Inspection of the fossil floras of the Cretaceous and Tertiary coal swamps points, in every case, to ample or moderate rainfall and relative mildness of climate. Some of the Cretaceous coals, even including those laid down in central Alaska, were deposited in environments probably no colder than that of Wilmington or Charleston on the Atlantic Coast. In other cases, the climate may have been subtropical. Nowhere do we find evidence of semi-aridity or of very severe cold, though frost, possibly somewhat severe, doubtless prevailed in the winters of some of the Tertiary coal fields surroimding the Arctic and occurring even on the Antarctic Continent. A noteworthy feature of these circumpolar coal fields of all ages is the existence of old soils, as in other fields, the woody composition of much of the coal deposit itself, and the apparent absence from the coal-forming areas of Arctic climate as it exists today. Trees of large size were abimdant in the coal-forming swamps nearly up to 82° north latitude and at about 80° toward the South Pole.

The distribution of coals in the high latitudes in the Mississippian, Jurassic, Cretaceous, Eocene, and Miocene formations, and the evidence presented by the coal plants for comparative moderation of climate in the regions of coal formation, strengthens the writer's belief that in the determination of climate and changes of climate, the epicontinental seas (their distribution, depth, form, size, etc.) were little inferior in importance to the continental configuration or the intercontinental connections. In comparing the climatic environments of both our older and our younger coal fields with present climates of the same regions, it should be borne in mind that the continents now stand high, perhaps near the maximum; many of the mountain ranges are young and still growing; the ocean is driven far down the continental shelves, and the epicontinental seas are drained or greatly reduced. From the geological viewpoint, present world climate is abnormal in its distribution and abnormal in its extremes. The earth's crust may be regarded as still in the midst of the post-Tertiary diastrophic revolution. The fluctuations in tide level and the deformation of the land probably were not greater or more frequent during the deposition of the Paleozoic or Mesozoic coals and their environing strata than they have been during the insignificantly short interval of Pleistocene time.

Deposition of the Coals

It has been pointed out that, in general, coals of the ordinary or common (woody) types were laid down in swamps in the form of peat. The typically woody coal was laid down in forested swamps in which a thin covering of water lay over most of the ground between the trees during at least portions of the year, the conditions being most like the swamps near the coast of the South Atlantic States before draining, and in some

Environmental Conditions Op Deposition Of Coal

of the tropical peat-forming swamps, such as those in some of the East Indies. Variation in conditions is plainly seen to have prevailed much as in peat-forming regions of the present time, though in the areas and times of widespread coal deposition the topographic relief was much less than at the present day.

In the paper by Doctor Thiessen, it will be shown that our coals present most, at least, of the features of composition seen in recent peats, though none of the extensive deposits of commercial purity were probably laid down in regions of so severe climate as peat of the Arctic tundra.

Water Level and Stagnation

Variations in the structure and character of the layers of the coal bed from point to point in the vertical section are mainly due both to the water level and to the composition of the water.

Where the water covered the surface of the organic deposit and was at the same time so stagnant as to conserve the so-called humic" or ulmic " or ulmo-humic " products resulting from the biochemical decomposition of more or less of the infalling vegetation, the decomposition solution soon became so concentrated at the level of peat growth as to be toxic and destructive to the agencies, mainly bacteria, causing the decomposition of the vegetable debris, so that further decomposition ceased in the toxic zone. The latter may have reached practically to the surface of the water, or it may have extended but little above the level of the peat. While this toxic condition of the water continued, a large part of the organic debris that sank in the water became buried in the peat formation with but partial or very little decay. It is evident that if, under favorable climatic conditions, the growth of the vegetation were lush and the contribution of the vegetable debris were consequently voluminous, the growth of the peat deposit would be very rapid. Further, as the greater part of the vegetal contribution was composed of vascular land plants, including of course trees, the deposit was, accordingly, woody and overwhelmingly composed of carbohydrate material.

A slower rate of contribution of the raw ingredient debris tended to favor the aeration (oxidation) of the water and consequent further progress of biochemical decomposition. Lesser degrees of toxicity of the water, caused, for example, by dilution of the decomposition solution by access of more water, permitted the same result. When, on the other hand, the water was replaced by influx on the one side and drainage on the other, or if the swamps were torrentially flushed, the ulmo-humic toxic decomposition products in solution were more or less removed with* the water, to which they gave the characteristic tea color; the toxicity was correspondingly reduced, and decomposition progressed much further

i*Thi5 subject is more fully discussed in The Carbonaceous Sediments: Treatise on Sedimentation.

David White

before it was finally checked at or not far beneath, the surface of the peat. Beneath the latter, and at no great depth, lack of circulation permitted stagnation of the water in the peat, which consequently became fully toxic and preventive of further decay at a depth depending, naturally, on conditions.

Biochemical Decomposition Selective

It is important to note at this point that biochemical decomposition is selective. The different component parts and organic compounds found in the vegetable matter contributed to the formation of the peat (coal) vary in the degrees of their resistance to biochemical (bacterial) decomposition in an aqueous medium, as is more fully explained in Doctor Thiessen's paper. Therefore the actual composition, as well as the structure of the layers of the peat bed, depends more or less largely on the degree of toxicity at the surface of deposition. The soft and delicate tissues of the plant (z. c., the parenchyma, the mesophyll, etc.) together with the protoplasm quickly disappear at the outset, imless the water cover is completely toxic to the microbes producing their decomposition.* If unchecked, decomposition extends to successively more resistant parts and organs, including later most of the woody tissues, and finally disintegrates everything but the outer, waxy, resinous, or waxy-resinous coverings of spores or pollen grains; some of the cutinized and more or less waxy or resinous cuticular formations; the most horny, waxy, fatty, or resinous coverings of seeds and fruits; the waxes secreted on the surfaces of leaves and stems, or in internal vessels and canals; the most resistant fatty or fatty-waxy deposits thickening the cell walls, stored in cell cavities, or deposited in the cuticles of some of the plants; and the resins of many kinds produced in the wood cells, in wounds, and on the surface of trees, leaves, seeds and fruits of many types. These plant products are almost entirely resistant to biochemical decomposition under water.

Effects of Changes of the Water Level

Essentially normal proportions of the resistant products are, naturally, laid down with the vascular, or woody, plant matter of the vegetation to which they belong in a deposit where biochemical decay has made little progress, though in these deposits the carbohydrate, or woody, matter vastly predominates. It is evident, however, that as the woody and other partly resistant compounds of the plants and trees successively yield to bacterial action, contributing their decomposition products to the aqueous solution which may thereby be made increasingly toxic, little except the most resistant plant products — exiles, waxes, resins, etc. — is left to accumulate, they being, in effect, concentrated. Exactly this

D. White: The Carbonaceous Sediments.

▼Ol. Lxxi. — 2

Venironmental Conditions Of Deposition Op Coal

happens at times of replacement of the water, or oxidation by aeration of the water, or of exposure with leaching of the surface of the peat so as to permit the decomposition of the less resistant plant products and substances.

Woody or Xyloid Coals

Accordingly, we find some layers of the coal deposited in toxic water and composed mostly of logs, stems, twigs, ferns, etc., with spores and other resistant elements mingled in a natural proportion. Most coal beds contain such layers, which are conspicuously woody, or xyloid. In other layers, the amount of well-preserved wood may be less and less, the resistant debris being in larger proportions; in still others, very little woody matter remains and the deposit may consist mostly, if not wholly, of exiles, fragments of cuticle, resin grains, scales or lumps, waxy secretions, and, rarely, particles of gum.

All these phases may be, and usually are, foimd — repeatedly — in a single coal bed. Layers or benches composed mainly of wood, twigs, etc. are somewhat irregularly intercalated with layers in which the wood is less in evidence and fine debris containing, of course, larger portions of resistant exiles, etc. forms a larger part of the deposit. In fact, as might be expected, and as may readily be seen, there is complete intergradation from the conspicuously xyloid type to what may be termed the spore type.

Those horizons in which more or less of the wood, as well as the less resistant plant material, disappeared by decomposition are usually duller in aspect than the woody deposits laid down beneath a continuing and fully toxic water cover; and when, as so frequently happens, films or thin layers of mineral charcoal are present, the edges or transverse fracture surfaces of the coals are distinctly mat. To coal of such general physical constitution and aspect, a number of British investigators have applied the name ''drain,'' evidently with the thought that it represents a distinctive chemical or physical ingredient of coals. In effect, however, the term appears useless except possibly in substitution for such adjectives as mat, which is not readily understood by the miner, or dull, a term not so agreeable to the coal operator.

The occurrence of lenses or strips of bright coal bedded in the mat portions is common and familiar to all who handle coals. These almost invariably represent more or less flattened twigs, branches, and logs that did not succumb to the decomposing microbes before they were surrounded by a solution so toxic as to preserve them. Meanwhile, in the course of time, they became permeated by the ulmo-humic decomposition products and, as now dehydrated, compressed, and lithified, they present the aspect of vulcanized rubber in the lower rank coals; of jet in

M, C. Stopes: On the Four Visible Ingredients in Banded Bituminous Coal. Proc. Roy. Soc. (1919) 90 , 470. M. C. Stopes and R. V. Wheeler: Monograph on the Constitution of Coal, 1918.

David White

coals of bituminous ranks; and of obsidian in anthracites. They are readily distinguishable in lignites, as well as in anthracites, if the examination is sufficiently close.

It is not improbable that occasionally logs and branches were either driven down or sank of their own weight far enough into the organic ooze to cause their preservation for the most part, while at the surface of the peat the toxicity was not sufficient to preserve most of the wood contributed to peat formation. Toxicity for short intervals would permit the survival of wood in such strips or 'stripes.' To layers or benches of coal of the more or less woody type containing this densely humified woody tissue enveloped as lenses and strips in the mat (drain) layers, the same English investigators have applied the term "clarain,'' which wholly without reason according to the writer's judgment, has been put forward, like 'Murain," as one of 'the ingredients of coal." It may be added that "vitrain," a term applied to another of the supposed "four ingredients" in the belief that it represents an amorphus or structureless accumulation of humic acid, comparable to dopplerite, appears to be only very densely humified wood or other plant tissue, in which, due either to too advanced carbonization of the coal or failure of technique, the vegetable structure was not seen.

Cannels

Where ponds, bayous, or very sluggish channels, too deep for the growth of trees, occur in the swamp, the agitation or replacement of the water favors more oxidation or flushing of the toxic decomposition products and permits the advanced decay of the reduced infall of land-derived vegetable matter, with the effect that little except spores and some resins* and waxes, left by the decomposition of the drifted land plant material, sometimes with occasional cuticles, remains in the organic ooze which at depth becomes toxic. Here the contribution of the organic matter is more or less uniform in substance though subject to some seasonal variation in rate, and the water cover is rarely, or only after a long time, reduced by filling of the depression or channel, so that we have a massive deposit, sometimes with very little evidence of lamination. This deposit is the typical cannel. It is always laid down in quiet water of slight lateral extent and too deep for land plants to grow in. If the mineral matter in the sediment is relatively large in amount, it becomes a ''bastard cannel" or "canneloid," or it may verge into a cannel shale if larger amoimts of terrigenous inorganic matter are included. Seasonal or imusual variation in the water level appears to result in lamination which, however, may not show until the deposit is buried, Uthified, and weathered.

w D. White: U. S. Geol. Surv., Pro/. Paper 85 (1914) 65.

Environmental Conditions Op Deposition Op Coal

Fat CanneU

Not infrequently minute floating algae — water flowers/' such as Reinr shia, Pila, Gloeocapsamorpha, or Elaeophyton — live in the pond or bayou and the undecomposed or but partly decayed remains of some of the more fatty or resistant of these mingled with the exiles and other normal constituents of the cannel, which the algae enriched by their generally waxy composition, the latter being high in hydrogen and comparatively low in oxygen .

Algal Coals

Where, as in larger bodies of stagnant or nearly stagnant water, which may be alkaline, the fatty algae formed the greater part or even the entire deposit, we have the typical boghead, with its characteristic capacity to yield large amounts of artificial petroleum by destructive distillation.

Lamination of the Coal

Lamination characterizes practically all coals and is seen on close examination in anthracites and sedimentary graphite. Seasonal or irregular flushing may cause lamination. Ordinary obscure and exceedingly thin lamination, not attended by deposition of 'mother of coal" is, however, probably correctly to be explained by seasonal variation in rate of contribution of the vegetable debris, by variation in the depth and concentration of the water, and by seasonal changes of temperature, all of which are found to produce lamination in recent silty deposits. It is, in fact, hardly to be doubted that the minute lamination has all the refinement of annual change in deposition. Brief seasonal exposure is not improbable, especially when the laminse are strongly marked as well as exceedingly thin.

Muck Films

Most coals show, however, a grosser and more variable lamination presenting phases which are hardly to be explained, except by exposure or oxidation of the peat-forming surface. Tliat such exposure occurred from time to time is plainly shown by the thin layers or films of mucky soft matter resulting from the oxidation of the top of the exposed peat, which, in fact, was being transformed to muck. Such layers are seen even in anthracite. They probably indicate exposure for more than a very brief season.

B. Renault: Les Micro-organisms des combustibles fossiles, 1893; H. Potonie: Entstehung der Steinkohle und der Kaustobiolithe, 6th ed., 1920; M. Zalessky: BvU, Soc. Geol. Fr. (4) (1917) 373; D. White, and T. Stadnichenko: Econ, Geol (1923) 18, No. 3; R. Thiessen, U. S. Geol. Surv. Prof. Paper 132-1 (1924).

David White

Fusain {Mineral Charcoal)

Other conclusive evidence of exposure, at times, of the surface of the peat is seen in the occurrence of fusain (mineral charcoal or mother of coal) strewn or matted in layers on the bedding planes of the deposit.

The prevalent belief that fusain is the result of forest fires, either in situ in the immense swamps, or on adjacent higher ground from which the charcoal was washed out over the swamps is quite incompatible both with theory and fact. The assumption that it results from fires on the surface of the exposed peat is inconsistent with the great extent of the fusain layers, the evenness of the bedding, the absence of corrasion pits or ash accumulations with supposed cinders, the normal state of the coal just beneath the fusain, the regularity and parallelism of the distribution of the fusain, generally in thin layers, the sometimes almost incredible closeness of the layers which may form a large part of the deposit in some of the beds, the purity of some of the layers, and the delicacy and orientation of some of the carbonized debris. Fortuitous forest fires could hardly have been so frequent and so regularly recurrent over the same great areas, and so widely destructive as these should have been, without leaving traces of ash accumulation or residue.

That the fusain cannot be charcoal drifted out from the land is shown by the continuity of its deposition; by the arrangement in normal position or relations of the charred '' fragments of such delicate material as fern fronds, pinnules and stipes, not to mention stems and branches; by the inadequacy of any transportation current to distribute charcoal evenly again and again throughout the great areas in the midst of the growing vegetation, and, especially, to do so without an accompanying film or sheet of land-derived mineral sediment, and, finally, by the inadequacy of any probable supply at the source. To assume that the erosion which would transport these vast quantities of charcoal out over thousands of square miles of coal-forming swamps would not at the same time erode the soil as well as wash away the plant debris is inadmissible. On the other hand, the fossilized peat surface offers no sign of erosion, nor of submergence beneath waters not the most tranquil.

In another publication discussing the origin of fusain, I am pointing out the insolubility of the 'ulmo-humic decomposition products in water at ordinary temperature after they have once been concentrated and dried, as pointed out by Collin Rae'® and others. With this fact in mind, the fragments of wood, bark, stem, fern leaf, and other debris, now fusain, covering innumerable bedding planes in the coal may be regarded as undecayed or partly decayed plant debris lying on the surface at times of exposure of the peat by evaporation of the water cover. Under these conditions, the evaporation-concentrated toxic decomposition matter

The Carbonaceous Sediments. .

Collin Rae: Amer. Assn. Pet. Geol. BvlL (1922) 6, 334.

Eivibonmental Conditions Of Deposition Of Coal

in the solution, impregnating and drying on the surface of pinnule, stem, and wood fragment would not only protect them for a time under weathering, but by the insolubility and toxic composition of the film or crust coating the fragments, would leave them protected and resistant to the renewal of microbial action, that is, further decomposition, on resubmergence, and the resumption of peat deposition.

In some coal beds and in benches of other beds, presumably laid down in a persistent water cover of the swamp, layers of fusain are relatively rare or even wanting; in others, they appear to form a large part of the coal. Rarely, it forms thin beds or lenses several centimeters in thickness. In some cases, it is jumbled and confused as by slight wave action. It is common in anthracite, though it appears to have been crushed in the course of the great pressure stresses to which the anthracite beds have been subjected. To a considerable extent, the thicker layers in anthracite are rubbed and eroded in the process of preparation of the coal for the market. Pennsylvania, Colorado, and WasWngton anthracites are apt to break along bedding planes covered by fusain, in spite of an apparent partial cementation in these layers.

Fusain is probably the source of the greater part of the dust in mines, tipples, and crushers of anthracite and other coals. Its structure, porosity, and friability suggest it as the principal source of the exceedingly comminuted and most easily ignited mine dust.

Effects of Water Conditions on the Initial Composition of the

Deposits,

As foreshadowed in the discussion of the conditions of deposition of the xyloid and the spore coals, and of the formation of cannels and bogheads, a very close relationship exists between water conditions and the initial chemical composition of the coals; i. e., in the peat stage. In the typical woody deposits, for which a thin perennial stagnant and toxic water cover is most favorable, the carbohydrates (lignocellulose, cellulose, etc.) form the greater part of the solid organic matter and as the coal passes through its subsequent alterative changes, its chemical composition is dominated by products of carbohydrate derivation.

On the other hand, where the water conditions favor the decomposition of the less-resistant organic debris and where even the greater part of the woody (carbohydrate) material decays, a large portion, perhaps nearly all, of the carbohydrates goes into the colloidal decomposition solution, more or less of which is carried away in the drainage of the swamp. The portion remaining in solution has lost its carbohydrate character through biochemical transformation, as wiU be shown in other papers of this series. Accordiny, in these deporits the chemical effects of the non-carbohydrate elements in the spores, resins, waxes, and other fatty plant secretions and products are more, and more marked, they

Discussion

having been brought into prominence by the disappearance of an otherwise overwhelming amount of woody matter. It is to be noted at this point that the resins and waxes, and the other resinous, woody, and fatty plant products, such as the spore and pollen exiles, and the fnments of cuticle, which are resistant to decay under water, are characteristically high in hydrogen and low in oxygen, quite the reverse of the carbohydrates. Therefore, as these form larger proportions of the organic sediment, the deposit becomes "richer," t. e., it is relatively higher in hydrogen and lower in oxygen and, in general, much higher in volatile matter. This is well illustrated by the cannels in which the woody tissues are reduced nearly to obliteration, though they doubtless contributed much to the decomposition solution now hardened as binder or groundmass in the deposit.

Still greater richness in hydrogen and volatile matter is added when, as in many of the cannels, fatty aigse, especially microscopic colonies of one-celled aigse of certain kinds with thick, waxy, or fatty cell walls mingle with the other plant debris of the deposit. Consistently, the bogheads, which are made up largely or almost exclusively of such algae, are the fattest (the most richly hydrogenous, and the most productive of volatile combustible matter) of the entire series of carbonaceous organic sediments. Not only are these bogheads, or algal coals, productive of oil in greatest amounts, sometimes as much as 135 gal. to the ton, when distilled, but the distillates produced by methods approximating as far as possible natural geological conditions approach nearest to the natural petroleums.

Variation in the amount of volatile matter in different layers of a coal bed is largely due to variations in the proportions, or in the concentration, of spore and other "fatty" ingredients, as compared to the amounts of woody matter, especially fusain, in the deposits.

The chemical contrasts between the types of coal, due to differences in the chemical composition of the ingredient debris and decomposition products, are greatest in the initial or early stages of alteration of the peat to coals of higher rank. Eventually, as will be pointed out in another paper, these initial chemical differences are obliterated as the deposit approaches the rank of anthracite. Meanwhile other distinctions develop as the result of geochemical changes in the buried deposits under geodynamic influences.

Discussion

Edward C. Jeffrey,* Cambridge, Mass. — The statement that the natural layers of coal represent a high degree of biochemical change is one td which I cannot subscribe because the microstructure of coal shows

Professor of Botany, Harvard University.

24 Envibonmental Conditions Op Deposition Op Coal

that the matrix layers are unusually well preserved. The matrix layers show a great deal of structure, more than the shining layers of coal.

As regards the origin of mother of coal, I also disagree with the author. I have microscopically examined a great deal of coal from all parts of the world and I think he has changed his attitude regarding mother of coal. Some years ago he thought that it was due to the action of the dry-rot fungus, or some similar organism on wood. If that were the case, the fungus would show some evidence of its presence, either the actual body of the funs would be present, or, if, the body disappeared, the holes that it always makes in the cells would be seen. Neither of those phenomena can be observed to any extent in mother of coal; I have examined an immense quantity of it. From the comparisons of recent deposits in water with coal, I have come to the conclusion that mother of coal is exactly what it is often called, mineral charcoal, the result of former forest fires. I think that is the only hypothesis that fits all the facts.

George H. Ashley,* Harrisburg, Pa. — One phase of this subject has not been touched on, though it is one on which we have all thought a good deal and which has more or less bearing on the general physiographic conditions in which coal is laid down; that is the origin of the thin partings. The more I have studied these, the more the question has arisen, in my mind, as to whether wind action may not have to be drawn on to account for the laying down of such very thin layers of practically uniform thickness, in many cases over hundreds or thousands of square miles. These thin partings seem to be of a different character from partings, here and there, that thicken toward what might have been a shore, as though they had been washed in by water and feathered out. These thin partings are often % in. thick and, as in the Pittsburgh bed or in the beds of the central interior field, sometimes can be traced over very large areas. What is known as the blue band in the No. 6 coal of Illinois, covers several thousand square miles and has a thickness of about 1 in., yet I cannot see how such a uniform bed could be laid down by water currents. It is a difficult thing to picture those conditions adjoining these great swampy areas.

Reinhardt THiESSEN,t Pittsburgh, Pa. — I am glad to have my theory of the origin of the thin bands of shale in coals expressed; I believe they are wind-bom deposits of eruptions probably, though many crystallographers disagree with me.

During the last three years, in my work on the correlation of coal beds, I have observed that all the coal beds in Ohio, West Virginia, and western Pennsylvania have been laid down in subsiding areas. The coal

State Geologist of PenDilvania.

I Research Chemist, Bureau of Mines.

Discussion

always begins at the bottom, with what I call anthraxylons coal, and in going toward the top of the bed it becomes more and more attrition. I think that at first it was a typical woody swamp and the moisture conditions increased imtil we had a typical aqueous swamp — the woody plants gradually giving way to more and more swamp-loving or waterloving plants until the whole area was covered by a typical aqueous swamp and finally by shallow water. At times, the subsidence seems to have been retarded and woody plants again appeared, but the surface seems to have subsided again and aqueous conditions continued until the area was covered by silt; very often the coal ends with a cannel coal, as is typically shown in the Freeport bed, showing that the aqueous stage was prolonged.

S. W. Parr,* Urbana, 111. — If we were to accept the fire theory of the origin of mineral charcoal, we would have to diagnose a kind of fire that has left a very uniform type of material. We calculated to the pure organic material, according to a habit of calculation that we have developed in our laboratory, that it would have stopped at a volatile constituent in the pure material varying; only 2 or 3 per cent. That would seem to be very difficult from the fire standpoint. From 17 to 19 per cent, of volatile matter is uniform with regard to this type of deposit. If we may accept a dual form of mother of coal, in which there is a higher ash content and in which the volatile factor is a little bit higher in one than in the other, we find another peculiarity of this substance. The normal mother of coal has no ash other than what we expect to be present in the wood ash and very low, corresponding in terms of the ash factor for the glance coal.

The other type of mineral charcoal, quite as unfortunate as fusain from my standpoint, sometimes runs as high as 25 per cent, in ash. All these high-ash layers are characterized by a very high sulfide of iron or very high carbonate of lime. That suggests that the very porous layer of mother of coal has had a secondary infield tracer and we frequently find calcium carbonate and pyrites associated. The heat value of the organic material in any of these types is almost exactly the same as pure organic substances of the coal.

David B. Reger, f Morgantown, W. Va. — The partings in coal interest us all very much and puzzle us even more; still I am loath to believe that any theory can be successfully established that calls for the transportation of this foreign material in solid form from a distance into the coal swamp, as it would be most irregular and unnatural for the same thickness to be carried for thousands of miles. If this were volcanic

Professor of Applied Chemistry, University of Illinois, t Assistant Geologist, West Virginia Geological Survey.

26 Envibommental Conditions Of Deposition Of Coal

matter, as has sometimes been claimed, it would necessarily be thicker at the source than farther out in the swamp, and the same thing is true of silt. But suppose that muddy water formed it. Every coal swamp has a small amount of in solution; then as the water evaporates (either slowly or rapidly as you please), having had a more or less constant depth over the swamp, there will be a deposit of probably uniform material with fairly uniform thickness, because a certain percentage is all the time coming out of the evaporated water as long as the water is in the swamp. Possibly, in the process, the water is agitated gently find the material is kept partly in solution, so that it settles slowly down into the peat and becomes a part of the coal and does not become a noticeable layer but is disseminated through the coal in formation. Of course, this process does not make a noticeable band, but if you assume that the water was evaporated quickly during some cycle of uphft or draft, it is easy to suppose that there will be a silt layer of constant thickness and perhaps fairly constant extent, just as we find the partings in the coal beds.

WiiiBUB A. Nelson,* Nashville, Tenn. — During the past year, some of the clays in the coal measures in Alabama have been found to be made up of volcanic material. Samples of those clays have been sent to the United States Geological Survey and they show Bentonitic material, as we have been calling it. The thickness of partings in coal seams could readily be accounted for as coming from a volcano, if the volcano was very far away. It is only when very close to the volcano, that there are great differences in the thickness of the ejected material. In the Mississippian rocks, there are many layers of clay that are very full of volcanic material — Green Bentonitic clays. This recent discovery in the coal measures in Alabama would indicate that if we study the coal measures more carefully, we will find other clays of a volcanic ash origin in these measures.

Rbinhabdt Thibssen. — The evaporation theory is not good in this case because plants, as we find them in the coal measure, will not grow in deep or even shallow water. I paid particular attention to the Freeport bed, where the coal comes up normally, that is, woody coal gradually becomes more and more mbced with mineral matter. In other words, the mineral matter in the bone begins in the first inch with the normal mineral matter content of the coal and increases gradually up to about 20 per cent., and from there on it stays rather constant or increases slowly imtil it reaches the maximum; then it gradually disappears until the coal again assumes the normal character. If we should imagine the peat covered with water to such a depth that we should have precipitation of, say, 11 or 12 in. of mineral matter, such a submergence would have killed off all the swamp plants living in it.

State Geologist of Tennessee.

Discussion

Geobob H. Ashlet. — The idea of volcanic origin of these thin beds appeals to me; they have been scattered through the whole body of our coal measures. What we call the "dint-clay bed" runs from central West Virginia into northern Tennessee; it is well down in the Pottsville. The Pittsburgh bed is near the top of the " Coal Measures." To account for these thin partings by assuming volcanic eruptions every time a coal bed was being laid down is stretching our credulity. The only other solution is to say that whirlwinds sweeping over practically desert areas lifted this matter very high in the air and allowed it to drift over and settle on these large swamp areas. 1 know of no conditions where similar deposits are being laid down in areas adjoining our deserts. It is difficult to think of laie deserts adjoining swamp areas, but this solution may have some bearing on our ideas of the origin of the coal.

Wilbur A. Nelson. — I will not say that all partings are necessarily derived from volcanic material, but I believe that many will be found to have that derivation. In a study of the coal fields of Tennessee, we have found a series of three or four parallel troughs. As one filled in with sandstones, shales, and coal beds, it was filled out to a barrier reef a distance of 10 to 15 miles; and then comes the next one, and then the next. That does not seem to agree with the theory of deserts next to the coal deposits. A very detailed study has shown this to be the condition of deposition in the southern half of the Tennessee coal field, and it is the same condition that has been thoroughly established as being responsible for the deposition of the Paleozoic formations in the great valley of east Tennessee.

Edward C. Jeffrey. — The question of the partings in coal, so faras they are produced by the substance known as mother of coal, should be envisaged and looked at from the standpoint of actual deposit. No doubt there are continuous layers of the charcoal from burnings on the land in actual peat deposits laid down in water and, further, not only are there continuous layers, but also isolated pieces of charcoal more or less irregularly diffused throughout those deposits. The only rational theory is that this charcoal originated from land fires and was washed into the water where it floated and sooner or later sank. For example, after a fire, I noticed quantities of charcoal floating on the surface of Lake Huron, and I imagine that is not an uncommon occurrence.

James F. Kemp,* New York, N. Y. — We should be careful to discriminate between what is native and what is infiltrated afterwards; the mention of carbonate of lime and pyrites would suggest that a large part of this material was infiltrated. I hesitate to speak closely about the actual composition of mineral charcoal, but the subject has interested me

' Professor of Geology, Columbia University.

28 Environmental Conditions Op Deposition Op Coal

because fossil Calamites are commonly visible in it. I presume that there were high-silica plants in Carboniferous times, very much as there are today, and that these might have formed a framework contributing a very high ash, compared with other forms of vegetation. The fumes of calcite and gypsum and other evidences on the joints in the coal show that there has been a good deal of infiltration, which would naturally go into the most porous parts of the coal, and those parts are the layers of mineral charcoal.

E. S. Moore,* Toronto, Ont. — It would be difficult to assume that these thin partings in coal seams were formed by evaporation. When you examine the composition of such a deposit, you would expect it to be very much higher than it is in the substances, like calcium carbonate, usually carried in solution, relative to the other constituents. It is also diflScult to assume that the partings all represent volcanic deposits. The only logical explanation that I have been able to find for them is in supposing that in times of high water some streams laden with fine sediment have broken levees and flowed over the swamps, spreading the sediment over very large areas.

I have just read Doctor J effrey 's work on Coal and Civilization, in which he so strongly urges the charred-wood theory for the origin of this material and have wondered whether he has not made the same error that so many of our mineralographers make in explaining our problems in ore deposits in the laboratory without reference to the structures in the fields. For a number of years, I have observed all the swamps associated with the burned areas I have come across in northern Canada and elsewhere, but I cannot see the possibility of obtaining the relative proportions and the associations found between the mineral charcoal and the other coal by any means of having this material washed in from burned areas in a region where you are going to get the great coal seams laid down. When most of the charcoal is carried off the burned lands into the bodies of water, great quantities of mineral sediment are carried in at the same time.

Edward C. Jeffrey. — Lands covered by vegetation, except under very unusual conditions, where there is a great fall of water, do not undergo erosion. My attention was directed to that a number of years ago, when studying plants growing in wet places, and I looked in vain for the seedlings until it occurred to me that they might make their appearance where the soil had broken away, and by searching there found them. It is easy to exaggerate the question of erosion in low areas, such as it is generally agreed, in the theory, that coal deposits were laid down. I do not believe that mineral sediments were laid during the active coalformation period. At any rate a very large volume of it was water with mineral absorption solution.

Professor of Economic Geology, Toronto University.

Discussion

Doctor Kemp is entirely right in his view that the mineralization of certain mother of coal, so-called, is due to the mineral substances in solution in water. It is not usually the case that lignite debris deposited in the day beds are filled with pyrites. Wood is the natural resting place of mineral matter, and we are investigating now the formation of crystals in plants. It has been supposed that it was the laying down of crystals that shade the mother of coal; that is, a coal or a matrix was laid down first and the crystal was laid down in that matrix. It is apparently a parallel case.

George H. Ashlet. — In the block-coal field of Indiana, there are three or four beds that consist of alternating layers of bright and dull coal. These beds run as much as 5 ft. thick, while the duU, and bright bands run not less than twelve layers to the inch. The whole bed is composed of alternate layers of mother of coal and glance coal, so that any explanation of mother of coal must provide for such a repetition of conditions as will produce these thin bands. The coal of those beds is characterized by being in small pockets, or basins — as many as four pockets have been mined in one small mine while some basins may be 15 or 20 acres in extent; the coal is limited to the basin, except possibly the topmost layer, which may run from one basin to another. That layer is not of the block character ; it does not have mother of coal, but is ' 'bituminous." There seems to be, therefore, some relation between the small basins and the presence of the mother of coal. These small basins cover a large, part of the eastern side of the Indiana field; so that a thousand square miles may be covered with these small basins of coal. The most reasonable explanation seems to be that these small basins have dried up during each dry season, or during especially dry seasons and the layers of mineral charcoal represent the dried surface of the peat.

Edward C. Jeffrey. — The mother of coal is not uncommon in cannels and oil shales, formed continuously under water cover.

Homer G. Turner,* Bethlehem, Pa. — My observations on anthracite have shown that, aside from any possible mineralization by means of pyrite or other minerals, there are several kinds of mother of coal. They vary from materials which are difiicult to scratch with the thumb nail, to those which are easily pulverized between the fingers. The hard materials show under the microscope either crushed cells or perfect cells with thick walls. The soft materials show perfect cells of the same type as those of the hard except that the cell walls are thinner. There seems to be every gradation from anthraxylon to material that closely resembles ordinary charcoal. This gradation suggests that chemical

Assistant Professor of Geology, Lehigh University.

Environmental Conditions Of Deposition Of Coal

reaction is a more logical theory for the origin of mineral charcoal than is the tiieory of forest fires.

David White. — We all agree that mineral charcoal (fusain) is present in coals of all ages since the beginning of forest growth on land. All the common types of post-Devonian coals contain it; in some coals it is very scarce and in some incredibly abundant. Sometimes the layers will not be mm. thick in matter seemingly evenly spread; yet, when examined closely, it will be found that neither the fusain nor the enveloping matter is distributed evenly.

"Mineral charcoal" consists of fragments of plant tissue not fully decayed. It embraces all kinds of wood, according to the geological period. In many of the Carboniferous beds there is no readily visible trace of Calamarise; equisetums and horsetails were relatively scarce in thd Tertiary swamps. Sometimes we find the most delicate fusain material scattered in these infinitesimally thin layers, hardly separated one from another by an appreciable thickness of glance coal, ordinarily not over mm., and rarely more than 1 cm. in thickness. Very delicate pinnules of ferns in which the nerves are transformed to fusain are sometimes found in the "mineral charcoal;" these must have been transformed in place in the swamp.

We sometimes make the mistake of predicating conclusions as to coal and its formation on an intensive study of a single bed with which we are particularly familiar or which we have subjected to special examination. I am perhaps quite alone in my theory of mineral charcoal (fusain) . The assumption that this material has drifted in such enormous quantities as to make up the greater part of the coal beds in some of the swamps is utterly incompatible with any assumption that coal is laid down in an immense swamp; the vegetation necessary to produce the coal could not grow in a swamp of such vast extent if the circulation was so Unobstructed by vegetation that charcoal drifting from upland or border land perhaps 60 to 70 miles distant has come unobstructed, and has been scattered in a thin layer over thousands of square miles. The extraordinary continuity of the fusain layers and their close proximity to one another, often with less than one-half millimeter of intervening ulmic matter, makes the drift theory little short of preposterous. On the other hand, the total amount of charcoal in some of the coal beds is really enormous. It can not have come from the land.

It is hard to understand how the charcoal would be formed in such great amounts on the land without destructive fires that would do more than destroy the growing tree — would probably denude the land. If there were a run-off such as is necessary to gather the charcoal and carry it out over the great swamps, this run-off could not possibly have failed to have extensively eroded the undersoil, stripped by the fires and laid

Discussion

bare for erosion. We would have had enormous amounts of ash in beds in which the charcoal brought by transportation was accumulated in such great amounts.

If the mineral charcoal were actually charcoal remaining from forest fires, coal beds containing large quantities of it should be relatively high in fixed carbon. On the other hand, the slight variation in the fixed carbon of layers containing much mineral charcoal accords with my explanation of its origin. The humic matter of the deposit not only enveloped carbohydrate material but partly transformed and, to an extent at least, it impregnated the woody debris.

From the circumstances of deposition of coal, it must happen during the long period required for the sedimentation of a thick bed that, due to the varying rate of subsidence or filling of the basin, the peat will at times be built above water level, so far as this may have been practicable, with occasional development of muck layers as the result of oxidation of the exposed peat; or, on the other hand, the vegetation will have been drowned out as a result of too rapid submergence. In the latter case, freer circulation of water over the submerged swamp would facilitate the distribution of fine silts and mud in muddy water, which would gradually settle in a layer possibly very thin but extending with relatively uniform thickness over great areas. Similarly, breaching of barrier bars as a result of too rapid subsidence would permit incursions of the sea, possibly with inwashing of sand over the peat. If the sea remained, even a short time, the fresh-water vegetation from which normal peat is formed would be killed, and if the excess of marine water was adequate marine fossils may have spread out over the swamp. Lingula and Discina were best able to endure the acid peaty bottom conditions. Goniatites apparently were relatively hardy. With clearer and less acid water conditions, marine mollusca, including coral, may have invaded the swamp. Of course, if the sea was not shut out and the surface *of sedimentation was not raised sufliciently by deposition of marine organic and inorganic matter, peat formation will have terminated and we shall have a marine shale or argillaceous roof over the peat previously formed. On the other hand, if the sea was excluded and the water cover was sufficiently reduced in thickness, fresh-water peat-forming vegetation of the normal types will eventually recover the old area. Marine partings, with marine organisms, may be not more than an inch in thickness.

limestones partings are extremely rare but, in the coastal swamp peats (coals), marine partings are probably more frequent than is generally supposed.

Partings resulting from flooding from the landward side of the swamp are characteristically more or less distinctly wedge-shaped and should be thicker and more arenaceous in the direction of the source of the sediments.

32 Bnvironmental Conditions Of Deposition Of Goal

I recall a number of volcanic explosions — Kilauea, Martinique and Katmai — that have contributed dust of rather widespread extent. A thin layer of volcanic ash settled on the pools and housetops at Newport, R. I., after the eruption near Martinique. The presence of volcanic ash in coal partings is not remarkable and, in view of the considerable time that may have been required for the deposition of the ''blue] band,'' in Coal No. 6 in Illinois, is rather to be expected and even looked for. However, I cannot admit that much of the inorganic detritus, not volcanic or cosmic, that makes up the ordinary coal parting, was blown to its present geographic position by the wind. The degree of aridity predicated by such eolian transportation is incompatible with the luxuriance of plant growth which characterizes most of our coal deposits. Certainly, a combination of wind-blown inorganic sediments with charcoal of forest-fire origin prepares one to expect a percentage of ash in the charcoal partings that is not present.

A. C. Chicago, 111. (written discussion). — This paper gives the condensed substance of an entire textbook on coal geology. It contains all essential facts in the history of coal deposits and allows us to visualize the processes of nature by which the great coal swamps were produced, were covered up again, were changed, and lifted out of place. The mining engineer may well be stimulated, by this paper, to look upon the peculiarities of the coal seams from an evolutionary point of view and to understand them better.

W. A. I. M. VAN Waterschoot van der Gracht, Ponca City, Okla. (written discussion). — This paper is an excellent and singularly complete description of the nature of the Palaeozoic and Mesozoic peat swamps, and the various conditions and factors that influenced the deposition and character of our coal beds. Unfortunately, I am less familiar with the American coal deposits than with those of Europe, but the author's statements apply to conditions observed in the Coal Measures deposits of northwestern Europe, from Silesia to the English Midlands and Scotland. Here also we have a broad and flat coastal zone along a very shallow epicontinental sea, to the north of a slightly rising continent: the first warping of what would later become the Herc 3 mian-Armorican front ranges. This epicontinental sea also had a northern shore, revealed only in the Coal Measures of Scotland, but buried farther east under the Mesozoic and Tertiary deposits of the north German plains and the Baltic.

Here, again, we find in the Lower Coal Measures singularly wide and uniform swamps, succeeding largely arenaceous and dominantly marine conditions. This densely overgrown, wide, flat coastal plain was entirely unbroken, except by occasional estuary lagoons and lakes. The same

Assistant Professor University of Chicago.

Discussion

coal seams can be traced from eastern Westphalia all the way through Holland and northern Belgium, and very often it seems that some should be correlated to such in northwestern France and even in England. This correlation is doubtlessly possible for some of the major marine invasions.

There apparently was a tendency for slightly deeper water west of the Rhine, in Holland and in the Belgian Campine, where the barren facies of the lowest Coal Measures gradually extends higher up in the series, consisting of a preponderance of massive, finely sandy shales, filled with a hash of mostly much decomposed and undeterminable plant debris.

In the middle Coal Measures, conditions become more variable: the coal seams, though thick and numerous, succeed each other rapidly, and are of far less lateral extent, indicating more differentiated and changing swamps of lacustrine character in wide and very flat lowlands. Marine invasions are practically absent, indicating that marine conditions must have retreated to considerable distance.

In the upper Coal Measures of Westphalia, Holland, and Belgium, conditions become still more irregular and the coal seams are usually full of intercalations of finely sandy shale beds. At least temporarily, marine conditions also become more frequent again and indicate occasional deeper submersion, sometimes depositing a thin limestone. Farther to the north, however, the few outcrops, limited to a few uplifts in the Teuton burger Wald, mark the prevalence of a more barren red bed facies with very few coal seams.

The uppermost, Stephanien, series is not represented in the known northern area, having been eroded before the deposition of the middle Permian, which (after the main diastrophism) commenced as a new shallow epicontinental sea (the Zechstein), which soon changed to a widespread saline formation and red beds, which continued all through the Trias.

The marine invasions in the productive Coal Measure series but rarely deposited thin marls or limestones with brachiopods; they generally consist of an often extremely thin black shale bed with minute dwarfed or very young goniatites and a few lamellibranchs; lingula is generally present and very often is the only indication of salt or at least brackish water conditions.

In the middle Coal Measures, coarse sandstones are entirely absent, only fine-grained sandy shales or fine shaly sandstones are found as intercalations in pure mud shales; higher up in the series coarser or even conglomeratic beds appear again, indicating nearby higher ground and stronger precursory earth movements of the orogenic phase of the late Carboniferous-Permian diastrophism.

All that the author says of the deposition of the coals holds true for the European Coal Measures. His description is so good that, in reading it, we almost feel trftpsfrred ipto these boundless tepicl swamps of the remote

VOli. LXXl.—ai

Environmental Conditions Op Deposition Op Coal

past, with a vetation so luxuriant that even the immense lush tropical swamps of Sumatra must fall far behind such riotous growth. In Europe, we observed that when water apparently became deeper, drowning out the vegetation in a swamp, Calamites apparently continued to grow longest in such lakes; while on the contrary, if lack of moisture seemed to have stopped peat deposition, the upper layers of the coal bed consist of dull mineral charcoal. When a salt-water invasion put an end to the growth, siliceous or calcareous 'coal balls" are common. How far should the Glossopteris flora in Arctic and southern Gondwana Coal Measures be interpreted as an indication of a different, possibly colder climate?

David White (author's reply to discussion).: — While it is more difficult to reveal the structure in the glassy layers of the coal than in the mat layers or "drain," where much refuse showing structure may be discerned with the naked eye, abundant debris of structural organization is present also in the former.

As to formation of mother of coal. Professor Jeffrey attacks a theory long abandoned by me. I hope, on the other hand, that I have shown that the old theory supported by him is untenable, whether or not my substitute explanation is later fully established.

I agree entirely with Doctor Thiessen as to the evidence of variations in the depth of the water cover, due to varying submergence, and their effects on the progress of biochemical decomposition and on the mechanical constitution of the sediments; but not as to the frequency and volume of partings composed of volcanic ash or dust carried by winds.

The Microscopical Constitution Op Coal

The Microscopical Constitution of Coal*

By Reinhardt Thiessen,! Pittsburgh, Pa.

(New York Meeting February, 1925)

Ingredient Materials Of Coal

In the general study of coal, all evidence points in the one direction — that coals had their origin in a manner analogous to that of peat. The best method of studying coal, whether it concerns its chemistry, composition, or physical condition, is to study peat. The essentials in a study of peat are a knowledge of the chemistry of plants, knowledge of decay and of the transformation process of plant-substances into peat. A number of facts must be emphasized, namely, (1) peat is formed under wet conditions only; (2) plants grow in the place where peat is formed; (3) all the plant substances go into the bog; and (4) all the plant substances are subjected to a series of phases of decay which are (a) in the air completely above the water level but in relatively moist conditions; (6) above the water level, but covered by debris; and (c) completely submerged by both water and debris.

Plant Chemistry

Plant chemistry as a whole is remarkably well understood. The number of compounds composing plants is large, and it is not possible here to give even a comprehensive outline, but a classification into definite groups is possible; this is as follows:

Carbohydrates; glucosides; pigments; tannins; acids, alcohols and ketones, etc., and their salts; essential oils; resins; vegetable bases; proteins; enzymes.

Plant substances may also be grouped according to the role they" play in the life of the plant, such as:

Framework materials, living materials, food materials, protecting materials, waste materials.

While this classification groups them well for certain purposes, it does not group them exactly chemically; but in a consideration of the composition of coal, this is an excellent classification for our purpose here.

♦ Published by permission of the Director, Bureau of Mines, t Research Chemist and Microscopist, Pittsburgh Experiment Station, Bureau of Mines.

Microscopical Constitution Op Coal

Carbohydrates

This group is a most important, but not the only important one. It furnishes the bulk and that part of the coal in which the other constituents are held. The carbohydrates embrace the following:

1. Monosaccharides.

2. Disaccharides.

3. Trisaccharides.

Dextrosans (starch-dextrin-lichenin)

. , V j 1 Levilosans

4. Polysacchandes , ,

' Mannans

Galactans Gum arabic

5. Gums Wound gums

Pentosans

6. Mucilages.

7. Pectins.

Pecto cellulose Ligno cellulose

Hemi-cellulose

8. Celluloses Normal cellulose

Compound cellulose

9. Cutin.

10. Suberin.

The carbohydrates differ greatly in the ease with which they are attacked by agencies of hydrolysis and decay. The mono-, di-, and trisaccharides are all water soluble and most of them are fermentable and food materials, but a few like talose and tagalose are entirely unfermentable. The polysaccharides must first be hydrolyzed before they can be fermented. They yield glucose on hydrolysis, which may be accomplished by dilute acids or by enzymes.

Gums

Gums are found in the wood of plants and trees, from which they often exude, as in the cherries and peach, corn stalks, straw, etc. On hydrolysis, the wood gums yield almost pure pentoses; they are therefore called pentosans. The wound gums yield arabinose; other forms of gum are gum arabic and gum tragacanth. The gums are hydrolyzed with difficulty, and for this reason are poor foods for animals and for micro-organisms.

Mucilages

Mucilages are secreted by certain hair-like organs on the skin of plants, leaves, and fruits. Their chemical composition is not known. When hydrolyzed, they yield arabinose, galactose and mannose.

Reinhardt Thiessen

Pectins

Pectins are comnoionly found in fruits, such as currants, gooseberries, apples, pears, etc., and in many fresh vegetables, like carrots, turnips, etc. They are easily soluble in hot water and when cooled set into jellies. The middle lamellae of plant tissues are also composed of pectins. Pectine is hydrolyzable by acids forming glucose. It is also hydrolyzable by the enzyme pectinase secreted by micro-organisms. Gums and mucilages also form part of the tissues in wood and, as such, are important constituents.

Celluloses

Celluloses are by far the most important plant compounds to be considered. They are characterized by their greater insolubility and greater resistance to chemical reagents. They also differ greatly among themselves in this respect. Celluloses are classified into hemi-cellulose, normal cellulose, and compound cellulose.

Hemi-cellulose is found most abundantly in the cell walls of seeds, in the shells of nuts, rinds of fruits, seed coats of beans and peas, etc., and also form a small part of wood. They are more easily hydrolyzable than the other cellulose, and are thus separable from them.

Wood

In the ordinary leafy plants, as in herbs, shrubs, and trees, the actively living part of the plant is confined to the growing points, as in the tip of the roots and tips of the branches, and in a narrow zone between the bark and the wood of the stem in every part of the plant, called the cambium. In every case the growing point is the predecessor of the cambium in the stem. During the growing part of the year, the cells of the cambium divide actively in a plane parallel to the surface. The cells splitting off toward the outside form the cortex, or bark, those splitting off toward the inside eventually form the wood. In this manner the stems grow thicker. The new or young cells formed, whether in the growing plant or the cambium, at first consist of almost pure cellulose. But soon other substances are added to the cell wall besides cellulose from the protoplasm and the cell sap, consisting mainly of lignin, and small quantities of pectin, dylan, pentosan, and hemi-cellulose; later, still other substances are added mainly in the luminae, such as tannins, phlobophenes, resins, waxes, fats, and a few other substances. The process is usually termed incrustation or lignification and the sum of the substances is called wood.

The resins, waxes, fats, and oils may be extracted by means of certain solvents, the tannins may be removed by boiling with water; the pectins and pectocellulose may be removed by hydrolysis with dilute acids by

Microscopical Constitution Op Coal

boiling; the pentosans may be removed with dilute sodium hydroxide in the cold; see Table 1. These processes leave the cellulose and the lignin intact, together called lignocellulose.

Table 1. — Analyses of Woods

(Results in Percentage of Oven-dry (105® C.) Samples)

1 Mois-

Solubility in

Species

—

ture

Ash

1 Per

Cold i

Hot

Acetic

Water i

Water

Acid

Western yellow pine

(Pinus ponderosa)

Yellow cedar

(Chamaecyparis noct-

katensis)

Incense cedar

(libocedrus decurrens)

Redwood (heartwood)

20.00 '

(Sequoia sempervirens) '

Western white pine '

7.00 !

4. '49

14.78 !

(Pinus monticola)

Longleaf pine

(Pinus palustris)

Douglas fir

Ifi.ll

(Pseudotsuga taxifolia) '

Western larch

j 0.23

(Larix occidentalis) '

j

White spruce

(Picea canadensis)

Tanbark oak

(Quercus densiflora)

Mesquite

(Prosopis juliflora)

Balsa

(Ochroma lagopus)

Hickory (shellbark)

(Hicoria ovata)

Eucalyptus

(Eucalyptus globulus)

Basswood

(Titia americana)

Yellow birch

2,67

(Betula lutea)

Sugar maple

(Acer saccharum)

1 G. J. Ritter and L. C. Fleck: Chemistry of Wood. Ind, & Eng, Chem, (1922)

14 1050.

Reinhardt Thiessen

Lignocettulose

What relationship the cellulose and the lignin hold to one another is a much debated question by plant chemists. One school holds that the cellulose undergoes a transformation into lignin, and calls it the 'transformation theory; a second school holds that the cellulose and lignin are combined as esters, and calls it the "chemical theory a third school, and the oldest one, believes a condensation of the esterlike nature of cellulose with small quantities of pentosans and pentoses takes place, to which are added in an unknown way other substances, called lignin. To these theories must now be added that of Wislicenus, called the "colloid-absorption theory. According to this idea, lignin is the sum total of the substances absorbed by the cellulose-fiber from the active cambium sap of the plant. Wislicenus holds that the cellulose and lignin are not combined chemically in any way but that they exist in the wood merely as colloidal mixtures. This theory does not preclude a chemical combination according to others.

The lignin and the cellulose in wood may be separated in two general ways: The lignin may be dissolved colloidally, leaving the cellulose undissolved, or the cellulose may be dissolved hydrolytically changing it to glucose and leaving the lignin undissolved. The lignin may be dissolved by treating wood with potassium chlorate; chlorine dioxide, boiling with phenol, caustic soda under pressure, sodium or potassium carbonate under pressure, and with acetyl bromide. The cellulose may be removed by hydrolysis with acids such as 70-per cent, sulfuric acid at room temperature, concentrated hydrochloric acid, 1-per cent, hydrochloric acid under pressure; gaseous hydrochloric acid; and glycerin-sulfuric acid mixture.

The amounts of cellulose and lignin obtained vary slightly with the methods used and widely in the different woods, age of the wood, whether sapwood or heartwood. Hardwood yields more than soft wood. Table 2 shows the quantities present in a number of woods.®

Cellulose

The plant chemist is completely in the dark concerning the chemistry of cellulose formation, but there are certain known facts that give a working hypothesis. The chemistry of the formation of starch is well understood. On hydrolysis, starch is degraded into glucose; cellulose likewise is degraded into glucose on hydrolysis. Although the relation

W. Wislicenus und W. Gierich : Beitrage zur Kolloidchemie der Zellulose. KoU loid-Zischr. (1924) 84, 169.

Wislicenus: Kolloid . (1910) 6, 87; (1920) 27, 209.

G. J. Ritter and L. C. Fleck: Chemistry of Wood. Ind. dk Eng, Chem. (1923) 16, 1056.

Table 2. — Lignin and Cellulose in Various Woods

40. Mickoscopical Constitution Of Coal

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Species

S.S 0 S.S 3.3

t mokory;

1 sapwood

2 heartwood. . . . V birch:

1 sapwood

1 heartwood

2 sapwood

2 heartwood

OpHPi©© SI,HpH©©

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1 sapwood

1 heartwood

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Reinhardt Thiessen

between cellulose and starch is not well enough known, it may be assumed that cellulose, like starch, is an anhydride of glucose;

CeHiaOe - H2O CeHioOg

It is therefore reasonable to assume that in the plant cellulose is also formed from sugar by splitting off water from glucose. There is a considerable difference of opinion as to whether the cellulose of all plants is the same. Most chemists hold that it differs slightly in different groups of plants. Heuser, however, claims that there is only one type of cellulose and this is the same chemical individual in all plants.

Three types of decomposition of cellulose are recognized: namely, acid hydrolysis, decomposition by dry distillation, and decomposition by bacteria and fungi. Although each of these has great significance, the last is of the greatest importance, and it only can be considered here. That bacterial action upon cellulose leads to degradation is known by the gases, such as methane, carbon dioxide, and hydrogen, and fatty acids that result. These substances are the last metabolic products of a biochemical process. A number of micro-organisms are instrumental in the decomposition of cellulose, and according to the metabolic products resulting may be separated into four groups as follows:

1. Methane forming, produced by sewage bacteria, and bacteria in peat bogs giving methane, carbon dioxide, and the lower fatty acids ranging from formic to butyric acid.

2. Hydrogen forming, produced by Bacterium fermentationis cellulosum, giving hydrogen, carbon dioxide, and the lower fatty acids.

3. Methane-hydrogen forming, produced by thermophylic bacteria of different kinds, giving methane, hydrogen, carbon dioxide, formic acid, and acetic acid.

4. Nitrogen forming, produced by denitrifying bacteria, forming nitrogen and carbon dioxide, and nitrogen assimilating bacteria, taking up nitrogen from the and air requiring cellulose for their carbon supply.

The active agents of decomposition are the enzymes secreted by the micro-organisms. As in all carbohydrate decomposition, two groups of enzymes are necessary for the decomposition of cellulose; those causing hydrolysis and those causing fermentation. Hydrolysis precedes fermentation, but the two proceed simultaneously. Through hydrolysis, by means of the enzyme cellulase, cellulose is decomposed first into cellobiose; and cellobiose is then changed into glucose by means of the enzyme cellobiase. Only after the glucose has been formed does fermentation set in. In this, a number of kinds of bacteria may take part, resulting in the products named above according to the conditions and the type of bacteria involved. Zymase is the enzyme active in this process.

Emil Heuser, Clarence J. West, and Gustavus Esselen: "Textbook of Cellulose Chemistry. McGraw-HiU Book Co., 1924.

Microscopical Constitution Op Coal

Lignin

In spite of the large amount of work done on lignin, it is impossible to give it a precise definition. Considering all the results obtained through chemical investigations, it must be concluded that lignin is not a unit or individual substance, and cannot be expressed by a definite formula. Many attempts have been made to give an empirical formula expressing its composition, but hardly any two investigators have arrived at the same formula. As to its constitutional formula, only a few suggestions have been attempted. Chemistry so far has failed to reveal its true constitution.

Different investigators obtain slightly different results in the elementary analysis of lignin. The carbon content is considerably higher in lignin than in cellulose. Table 3 shows the composition of lignin:

Table 3. — Analyses of Lignin

Investigator

Per Cent.

H,.

Per Cent.

OCHi,

Per Cent.

Fischer and Schrader®

H&gglund

Klason

Beckman, Liesch and Lehman. .

Franz Fischer und Hans Schrader: Ueber die Trockene Distillation von Lignin und Cellulose. Gesamm. Ahh. z. Kenntnis d. Kohle (1920) 5, 106.

® R. Riefenstahl : Der Gegenwartige Stand der Lignin Chemie, Zeii. f, angew. Chemie. (1924) 37, 169.

As to the constitution of lignin, it is assumed from one side that lignin is of an aromatic nature; this is denied by others. It has been proved that the lignin molecule contains a methoxyl (OCH3) group, the source of alcohol in lignin and in wood. The amount of methoxyl is shown in Tables 2 and 4. An acetyl group has also been shown to be present. Further it is claimed to have several (two or three) hydroxyl

groups, a carboxyl

c/

\Oh

)

group, and a ketone group.

The decomposition of many substances through various agencies may be followed step by step and the products determined at every step, thus affording a fair knowledge of the composition of the original substance. In lignin, this has not been possible and little has been learned in this manner. Yet the products obtained through various agents of decomposition and the behavior of lignin during the processes have furnished valuable data as to its nature.

Reinhardt Thiessen

Table 4 . — Ratio of Methoxyl to Lignin in Ovenry (105® C.) Weight of

Species

No.

Lignin

OCHs

OCHi X 100 Lignin

Sap-

wood

Heart-

wood

Sap-

wood

Heart-

wood

Sap-

wood

Heart-

wood

White ash J

f

Yellow poplar J

f

.f'lc hifikory

Red alder j

f

Bald cypress j

f

Fastem white pine

Yellow cedar

Southern white pine J

f

[

Incense cedar

G. J. Ritter and L. C. Fleck : Chemistry of Wood. VII, Relation between Methoxyl and Lignin in Wood. Ind, & Eng. Chem. (1923) 16, 1264.

The lignin molecule may be decomposed by heating with alkalies, by strong reducing agents, and by oxidizing agents. The decomposition products may be separated into those that indicate an aromatic character, like phenol, quinone, vanillin, protocatechuic acid, and pyrocatechin; and such products as indicate an aliphatic character, like succinic, masonic, acetic, formic, oxalic and adipic acids. Furfural is claimed to have been found by some chemists, but its presence is doubtful.

When lignin is subjected to fusion with potassium, it results in a human-like substance, from which may be separated protocatechuic acid, pyrocatechin, vanillin, and adipin in varying but small proportions, according to the conditions imposed upon it. Oxalic acid may be separated in rather large quantities, as high as 20 per cent. Lignin is not attacked by weak reducing agents and energetic reagents like zinc dust, iodic acid and phosphorus at higher temperatures must be employed. The products are hydro-aromatic hydrocarbons of unknown composition. On the other hand, oxidizing reagents, like ozone, hydrogen peroxide, potassium permanganate, hydrochloric acid, and chlorine dioxide, decomposed lignin easily, resulting in decomposition products of low molecular weight that give no clue as to its constitution. According to the reagents used and conditions imposed, varying quantities of oxalic acid, carbon dioxide, water, formic, acetic, and succinic acids are obtained.

Microscopical Constitution Of Coal

The main product is oxalic acid; as much as 20 per cent, of oxalic acid was found.

The products obtained from lignin by dry distillation depends, as with other substances, on the conditions of heating. On heating it to 500® C., Heuser and Skioldebrand obtained 15.8 per cent, tarry water, 13.0 per cent, tar, and 50.6 per cent, carbon. Fischer and Schrader report 10.2 to 13.9 per cent, water, 12.3 to 14.4 per cent, tar, 15.8 to 19.2 per cent, gas, and 57.0 to 57.2 per cent. coke.

The gases consist of carbon dioxide, carbon monoxide, methane, and a hydrocarbon CnH 2 n. Noteworthy is the low carbon dioxide and the high carbon monoxide and methane.

The watery distillates are composed of water, acetic acid, acetone, methyl alcohol, and perhaps vanillinic acid.

The tars consist of 13 per cent, neutral substances, 34 per cent, phenols, 16 per cent, acids, and 37 per cent, water-soluble organic substances.

Calculated for the original lignin we have 1.6 per cent, neutral constituents, 4.2 per cent, phenols, and 2.0 per cent, acids.

Lignin is attacked but slowly by bacteria and fungi. Little, however, is known in this respect. Most fungi do not attack lignin when inoculated. A few fungi, however, one in particular, Trametes pint, will attack lignin in wood but not the cellulose.

Bark

Bark is a very complex substance, consisting chiefly of bast fibers and cork. The composition of cork is also complex, and a number of complex substances, like phellonic acid, an alicyclic compound, phloic acid, and suberic acid, have been isolated from it. A large number of other complex substances have been isolated from various corks. The main substance in cork is suberin. Its composition is not known, but it is said to be similar in composition to fats and waxes.

Cuto-Cellulose

The term cuto-cellulose is applied to covering membranes or cutins of plants; their composition is not well known. Recent investigations show that they consist of esters of glycerin and fatty acids, and esters of higher alcohols and fatty acids, mixed with free fatty acids, and alcohols and other substances. Cuto-cellulose form the principal protective tissues. They are very resistant to oxidation and weathering, and to bacterial and fungal agencies.

It was assumed for a long time that the so-called cuto-cellulose was a combination of fatty, waxy and resinous substances with cellulose. Recent investigations® show that no cellulose is present in the compound.

Roscoe W. Thatcher: "The Chemistry of Plant Life.'' McGraw-Hill Book Co., New York, f921.

Reinhardt Thie8Sen

Glucosides

Glucosides are ethers of some monosaccharide, usually glucose, with some closed-ring benzene derivative. They are very common and universally present plant compounds. There are a number of types, such as phenols, alcohols, aldehydes, acids, oxyflavons, anthraquinone, nitriles, pigment, etc., embracing a large number of glucosides. The following are a few of the well known: arbutin, digitalin, hesperidine, quercitin, salicin, cyanin, coniferin, malvin, populin, indicein, amygdalin, apein.

The natural glucosides are hydrolyzed readily by boiling with dilute mineral acids, and easily by enzymes that occur in the same plant tissues but in different cells: The primary products of hydrolysis are glucose, or in some cases some other monosaccharide, and some closedring benzene derivative. A large number of enzymes have been isolated, many of which will hydrolyze only one specific glucoside. Microorganisms are able to hydrolyze glucoside in a similar way by means of enzymes. The hydrolysis of the following glucosides shows at once their structure and the typical reactions:

1. Arbutin, C12H16O7

Ch 20 H

Oh

! +H 2 O C6H,206 +

HCv JCH

H

Oh

arbutin

hydroquinone

2. Coniferin, C16H22O8

H Ch.Ch2Oh

mCBOSCOPICAL CONSTITUTION OF COAL

CH= CH.CHsOH

in

coniferyl alcohol

+0

Cho

A

H

CH„060CJl3o.04.CH

Cn

H

Hc

iCH +.H 2 O HO

Ch

Ch+C,H,20,

CHiiOs.O.CH

Cn

amygdalin + water mandelonitrile glucoside + glucose

H

CeHu02.0.iH

Cn

Hoin

'iN

mandelonitrile glucoside + water mandelonitrile + glucose

Bbinhardt Thiessen

H

Hoch

H

Cho

Cn

mandelonitrile + water benzaldehyde + hydrocyanic acid.

These examples of reactions and structure are sufScient to show their general nature. The sugars resulting from the splitting are foods for both bacteria and fungi and are quickly decomposed. The benzene derivatives are not further available as food for organisms of decay, and must contribute to the deposit, absorbed by the woody degradation matters. Some of these have been found in peat and in rotten wood, and are responsible for the peculiar odor in rotten wood. Vanillin, for example, is a constant substance in both rotten wood and peat. When coal is dissolved by means of Schulze's reagent, the smell of rotten wood is pronounced. The disposal of the glucoside in peat is yet a closed book.

Of particular interest are the pigment glucosides, as they are the possible mother-substances of the dye substances found in coal tars. These are probably the most general and universally present of the glucosides. To be assured of this, one has only to look around and observe the different colors in plants other than green, particularly in the fall. Most, if not all of the red, yellow, blue, and violet are due to these glucosides.

There are four basic types of these glucosides: those with the anthraquinone nucleus, giving rise to the alizarine reds; those with the zanthone nucleus, the yellows; those with the flavone nucleus, also the yellows; and those with the anthocyan nucleus, giving rise to the interchangeable soluble red, blue, and violet colors. They are all of the condensed benzene ring type, two rings being united by a third, in which there are either two atoms in the ring and one atom and a second attached to the opposite carbon in the (C 0) arrangement.

laCBOSCOPICAL CONSTITtmON OF COAL

Indican also belongs to the pigment glucosides, but its constitution is of an entirely different type. The glucoside hydrolyzes to indoxyl, and this is easily oxidized to indigo, the important dye.

Indican Glucose Indoxyl

70N + H2O CeHwOe + CsHjON OCcHiiOs H

Ch

V /

Ch

Hc'X . %/

N

C N

H H

H

Reinhardt Thiessen

H

I!

o

H

Tannins

Tannins are either free phenol acids, or more often gliicosides of these acids. Common tannin yields 7 to 8 per cent, of glucose on hydrolysis. Each glucose molecule has five phenol acid groups attached to it. Tannins also are common and universal plant products. Barks, as well as many leaves, are particularly rich in tannins.

Essential Oils

Terpenes and Camphors . — Terpenes are important substances in consideration of the constitution of coal. They are common plant products, frequently associated with the resins. Resins and balsams are often the solutions of resinous acids in terpenes. The conifers are particularly characterized by secreting large quantities of terpenes, but many other plants are also rich in terpenes and essential oils. Like the resins, they are found in special cells, ducts, and reservoirs in the wood, bark, and leaves. They behave as unsaturated compounds, and are almost all oils of high boiling points. They volatilize without decomposition in steam, polymerize easily, and reorganize on heating slightly. When exposed to the air, they oxidize and harden. They are not decomposible through micro-organisms. Many of them are bactericides and are used as disinfectants. Several different types are recognized as follows :

Hydrocarbon oils or terpenes

Oxygenated

and

sulfuretted

Hemiterpenes CsHg Monocyclic CioHie Bicyclic CioHie

Polycyclic (CsHs)!!

Hydroterpenes CioHw and CioHjo Oxygenated, usually called camphors alcohol, ketones, aldehydes, acids, esters, or phenol derivatives of the former.

Sulfuretted oils

YOJs. ucxi,— 4

MlCBOSCOFICAI< CONSTITUTION OF COAU

The following are common examples:

Menthane CieHao (hydrocarbon)

CHs

(Ih

Menthol (C10H20O) (alcohol)

Ch,

Ch

Menthone (CioHisO) (ketone)

Had

c=o

H

Ch

Reinhabdt Thiesssn

Ch*

Buccocamphor (CiiHu02) (ketophenol)

(hydrocarbon)

Borneol CioHitOH (alcohol)

H

Ch,

H 2 C (!) C O

Camphor CioHigO (ketone)

Resins . — Like the terpenes, resins are deposited as a waste matter in the wood, bark, and leaves of many plants, but most abimdantly in the conifers. They are stored in and held in special vessels, the resin vessels, schizogenous cavities or pockets and canals. Many often appear as a

Microscopical Constitution Op Coal

viscous solution in terpenes, called balsams and turpentines. Their mode of formation is not known.

When dried they are amorphous, brittle, yellow-brown substances. At first, they may be but lightly colored or colorless; but when exposed to the air, they often harden and assume a dark-brown color through volatilization of the terpenes, but primarily to oxidation becoming solid substances.

Chemically considered, they are composed of a mixture of resinous alcohols and phenols, partly free and partly in the form of esters with resinous acids or other acids. The amount of free acids is variable; some resins are composed almost entirely of free acids. Specific components of resins are: Resinic acids or resinole acids, resinic alcohols or resinols, resinic phenols, resinic phenols with tannin characters or resinic tanols, resenes. As far as they are known, they are ring and conjugated-ring compounds and their derivatives. Terpenes are present more or less as solvents. With these mixtures many other substances may be present.

The resins are insoluble in water and acids, but easily soluble in organic solvents, like ether, benzol, alcohol, and chloroform. They may be more or less completely saponified by alkalies, and are not subject to bacterial decomposition.

Resinic Adds , — Although the chemistry of the resinic acids is still incomplete, they are better understood than the other components of the resins. They are soluble in alkali carbonates. They are probably related to the terpenes. It has been shown by Tschirch® that retene is formed when resinic acids of conifers are distilled; and Vesterberg has succeeded in converting abietinic acid into retene. This leads to the belief that they are derivatives of retene (CigHig)

CHa

Hc

H

V

C— CiJIr

H

Ch

The same residue is found in fichtelite, a fossil resin.

Different plants do not contain specific acids. In other words, specific acids are not characteristic of certain plants, but are found in mixtures of related forms that will differ not only in different kinds of plants, but also in the same plant under different conditions and at different times of the year. They are not stable, are sensitive to heat exposures; and are

A. Tschirch : Die Harze. Gebr. Bomtrager, 685. Leipzig, 1906.

' A. Tschirch : loc, cit.

Beinhabdt Thiessen

easUy oxidized. They are optically active. The best known are abietinic acid and pimaric acid.

H2 H2

ResinoUs . — The resinoles are crystallizable; their character is "partly that of phenols, and partly that of alcohols. The best known is amyrin, C30H19OH, a triterpin, found in elemi resin.

Resino Tanols , — The resino tanols are amorphous, aromatic alcohols, with characters of tannin. When distilled they yield aromatic hydrocarbons, and when oxidized with nitric acid they form picric acid. The resenes are but little known.

Fossil Resins . — The study of fossil resins sheds considerable light on the resins in coal. Like resins, fossil resins are complex compounds and often mixtures of compounds. Amber is the general expression for a fossil resin. But amber, like resin, is not a specific term for a specific substance, but is a collective name for a number of substances or mixture of substances. More precise names for fossil resins are succinite and fichtelite, the best known of a long list. Succinite is the resin found in

Microscopical Constitution Of Coal

fossil pines, Pinus succinifer and Pinus sylvatica, Pinus Baltica and Pinu8 cembrifolia.

Succinite has been the object of a series of investigations over a considerable time. The great difficulty in its investigation lay in its difficult solubility in all solvents. After many months of treatment with alcohol in a reflux condenser, only about 30 per cent, was soluble. This part was found to consist of borneol and succino-abietinic acid. The borneol amounted to 2 per cent, and succino-abietinic acid 28 per cent, of the total succinite. Being found in many conifers, it is assumed that borneol and abietinic acid are present as an ester.

The remaining 70 per cent, was not completely soluble in all known solvents, none having the least effect on it except chloroform and carbon disulfide, which caused it to swell considerably, but dissolved but very small quantities after days of boiling. After repeated renewal 0.5 per cent, of alcoholic potassium dissolved 7.8 per cent., which proved to be succinic acid. After further treatment with alcoholic potassium, the remaining residue proved to be a resinole, C12H20O.

Fichelite is another substance that gave up its secrets only after repeated attacks of a number of investigators over a considerable number of years. It withstood every attempt to split the molecule step by step. It was finally shown to be a perhydrate of retene: C18H32.

Fichelite

/X

>Ch

H,CCi

Cc3H,

H

Retene

Abietinic acid, CigHjgOj, which has a similar structure, has been changed into retene.

Rbinhabdt Thiessen

Vegetable Bases

In the vegetable bases, we find characteristically nitrogenous compounds of plants. They may be divided into three groups: Plant amines, which are simple open chain compounds; alkaloids — simple closed ring compounds, including a nitrogen atom in the ring; purine bases — complex compounds containing a nucleus with four nitrogen atoms arranged alternately to form a double ring.

Amines

The simple amines may be considered to be derived from ammonia or ammonium hydroxide as follows:

/H /R /R /R /R yH

R

N-

-H N H N-

-R N

R ,N H

R ;n „

The ptomaine poisons are examples of this class:

Oh

HsC HsC H

H3O

H,C

H,G

./

CHy— CH

-N

''Oh

Oh

Muscarine'

/Ch Ch*

-N

\Oh

Neurine

Micboscopical Constitution Op Coal

Phenyl derivatives are also found, like

hydroxyphenylethylamine : HCK Hg.CHa.NHs

and hordine : HO<(

These, however, are probably of no great importance as mother substances of nitrogen in coal, because on hydrolysis the nitrogenous product would further decompose to ammonia.

Alkaloids

Alkaloids are vegetable bases whose nitrogen is part of a heterocyclic closed-ring arrangement. They are insoluble in water. They may be grouped according to their structure into the following groups: Pyrrolidine group:

Pyrrolidine

Other members of the group are stachydrine and hygrine.

The pyridine group:

H

Pyridine

Other members of this group are piperidine, nicotine, and conine:

H2

Rbinhabct Thiessen

The tropine group:

Cocaine and atropine also belong to this group. The quinoline group :

H H

H

to which also belong quinine, strychnine, and cinchonine. The isoquinoline group:

H H

to which also belongs morphine with a very complicated structure. Some alkaloids are composites of two or more of these groups, like nicotine, which is a combination of pyrridine with a pyrrolidine nucleus. A large number of alkaloids are now known.

Purine Bases

Purine bases are widely distributed in plants. They may all be thought of as being derived from purine:

Microscopical Constitution Op Coal

Hc C

! li

'!

N --- C

To this class belong, among many others: xanthine, uric acid, guanine, theobromine, theophylline, and caffeine.

Biochemical Decomposition

A knowledge of the chemistry of plants alone will add but little to a comprehensible knowledge of what the plants contribute to coal, because plants did not contribute their products in their original state nor did all remain to contribute. Long before the real coalification processes began, the contributing plant matter was subject to a drastic biological transformation — in brief, decay. Before going any further, we must inquire more thoroughly into the question as to what is decay, what is the mechanism of decay, and what are the results and products.

Decay

Micro-organisms require food for building up their bodies and to supply energy. The sum of the changes going on in the body is called metabolism. Metabolism consists of several separate functions: the building up of the body, called anabolism; the deterioration or tearing down, called katabolism; and the most important one, to supply energy, called respiration or fermentation. The last function is well known and may be produced in the laboratory without micro-organisms. The processes of katabolism are partly known, while anabolism or the synthetic processes are known but very little. Many organisms live upon cellulose, starch, fat, gelatin, keratin, and other water-insoluble foods. But their life processes depend on water-soluble foods, or foods that will diffuse into the cell wall and come in contact with the protoplasm where all metabolism takes place. But as insoluble foods do not diffuse into the cell and the protoplasm cannot diffuse out, the insoluble foods must first be transformed into soluble ones. This the organisms accomplish by secreting substances that will split the insoluble foods into soluble parts. The substances that bring about these transformations are called enzymes. The soluble compounds thus formed can then diffuse into the cell of the micro-organism, where they are digested or fermented, by the aid of other enzymes, and yield the energy for the cell, and build up the cell. Many lds of enzymes are known, each one acting in a specific way on a specific substance. It

N-H

N

Beinhabdt Thiessen

will be seen then that the process involves two definite stages: food preparation, and digestion or fermentation, also called respiration. The insoluble foods often are broken down step by step before they are actually ready for the final step. This is well illustrated by fungi living on starch. Starch is first changed by means of the enzyme diastase to maltose; maltose is split by maltase to glucose; glucose diffuses into the cell where it is finally changed by the aid of zymase to alcohol and carbon dioxide. This last change is the vital one; it furnishes the energy required. The first steps are preparatory. The organism could live equally well on maltose, in fact, more economically. Another example is found in bacteria living on cellulose, as already noted. These secrete the enzyme cellulase. Cellulase changes cellulose first into cellobiose and cellobiose is then changed by the enzyme cellobiase to glucose, glucose is diffused into the cell where it is fermented by means of the enzyme zymase to alcohol and carbon dioxide or the glucose may be changed into other substances. The last stage furnishes the energy. It cannot live on alcohol and carbon dioxide!

It must not be thought that decomposition of starch and sugar is always as simple as given in the examples. To discuss the various ways in which the sugar, starch, and other carbohydrates may be decomposed would go too far for this purpose, and cannot even be outlined here. Besides alcohol and carbon dioxide, organic acids are also formed in certain cases. The organic acids and alcohols can be decomposed further by both bacteria and fungi, and by some yeasts, to simpler compoimds. Ordinarily, this decomposition consists in complete oxidation. The acids are completely oxidized to carbon dioxide and water. Alcohol is first oxidized to acetic acid, and this to carbon dioxide and water.

The discussion and example just given plainly show two kinds of reactions. The one is hydrolytic and the other fermenting or respiratory. Besides these in bacterial decomposition, two other groups are distinguished; namely, oxidizing and reducing.

Enzymes may therefore be classified as follows:

Hydrolytic enzymes:

1. Of carbohydrates: cellulase or cytase, diastase or amylase, invertase, lactase, maltase.

2. Of fats: lipase.

3. Of proteins (a) proteolytic: pepsin, trypsin, erapsin; (6) coagulating: thrombase, rennet.

4. Of glucosides: emulsin.

Zymase or fermenting enzymes:

1. Of carbohydrates: zymase, lactacidase.

2. Of other nitrogen-free bodies: vinegar — oxidase.

3. Of proteins: endo-tryptase, amidase, urase.

Microscopical Constitution Of Coal ,

Oxidizing enzymes:

1. Oxidase, tyrosinase.

Reducing enzymes;

Catalase, reductases of nitrates, sulfur, sulfates, etc.

Probably all micro-organisms produce several to many enzymes. As was shown before, several are necessary to decompose a substance hydrolytically before it can ferment; diastase changes starch to maltose, maltase changes maltose to dextrose, and finally the Zymase changes dextrose to alcohol and carbon dioxide. The number of enzymes in some organisms is large. It has been found that Aspergillus nigar and PeniciUium camenberti produce almost all the enzymes that have ever been found. Many organisms live on the products of others; this is called symbiosis. In some bacteria, a symbiotic relationship is absolutely essential.

The two terms hydrolysis and respiration or fermentation cover air the principles underlying decay. The term putrefaction is often used, particularly when decomposition is accompanied by fetid odors. As bad odors are due to certain sulfur compounds and as these can only be formed from organic substances containing sulfur, like the proteins, putrefaction has come to mean protein decomposition. The statement is sometimes also made that putrefaction is caused exclusively by anaerobic bacteria. It was first used by Justus Liebig in this sense. This is incorrect, as both aerobic and anaerobic bacteria are instrumental in proteolitic decomposition, in fact aerobic more generally than anaerobic.

Types of Bacteria and Fungal Decay

In the previous section was described the mechanism of decay by bacteria and fungi, but it is also of great importance to take into consideration the types of bacterial and fungal decay.

We have already seen that plants alone can manufacture carbohydrates, by means of a process called photosynthesis with the aid of cUorophyl and light. From the carbohydrates, the plants manufacture further proteins, by the addition of an NH 2 group obtained from nitrates in a manner as yet unknown. As in bacteria, this process ofbuilding up is called anabolism. The plant also carries on other life functions, that of tearing down, called katabolism. By this process, many other plant products are formed, usually termed waste products, already mentioned. All the functions of the plant taken together are called metabolism, and produce the plant with all there is to it, the plant as a whole. Animals depend solely on plants for their existence, and the few changes that occur from plants into animals may be ignored for the purpose of this study.

With few exceptions plants, together with that part transformed into the animal body, constitute the organic matter on earth. All

Beinhabdt Thiessen

organic matter is undergoing continuous changes. Organisms not only grow, they also decompose. The same carbon, hydrogen, oxygen, nitrogen, and sulfur molecules that chiefly constitute the organic world of today, constituted it as long as life has existed. While green plants build up the organic compounds, the bacteria destroy them. Without bacteria, the world would soon be filled with undecomposed organisms and new life would soon be impossible. The substances that compose even organisms therefore go through cycles, as discussed in the following section.

The Carbon Cycle . — Carbon is the most important element in life. Beginning with the simplest compound, carbon dioxide of the air, it is absorbed by the green plants and is changed, together with water, into carbohydrates, like sugars, starch, cellulose, lignin; or into fats, acids, and to protein on further addition of nitrogen from nitrates, and sulfur from sidfates, and to other substances. The plants will either die and decay, or be eaten by animals that die and decay. Both plants and animals are decomposed step by step, until finally returned to carbon dioxide and water. Even methane, alcohol, and the toxic compounds, as morphine, nicotine, and others, are eventually returned by bacterial action to the elements.

Both hydrogen and oxygen are so closely linked with the carbon atom that they may be said to go through the same cycle with the carbon atom. In fact, in most cases, it is the oxygen atom the bacteria arfe after.

The Nitrogen Cycle . — Nitrates in a large measure, and ammonia to some extent, constitute the sources of nitrogen of the higher plants, which transform them into amino acids, amides, and proteins by combining the NH2 ion derived from them with carbohydrates previously manufactured by the plants from carbon dioxide and water. Leaving out of consideration the part played by animals that live on plants, there are eight or nine well-known phases of transformation of nitrogen by micro-organisms:

Protein decomposition.

Ammonia formation.

Nitrification.

These three constitute the normal steps in the mineralization of nitrogen and are the counterpart of the processes performed by the higher plants.

Reduction of nitrate to nitrite and ammonia

Assimilation of amino and ammonia.

Assimilation of nitrate nitrogen to proteins.

These three constitute the retrograde changes and are in competition with higher plants.

Denitrification or liberation of nitrogen from nitrates or nitrites.

The oxidation of ammonia to free nitrogen and water.

Fixation of free nitrogen.

inCBOSCOPICAL CONSTITUTION OF COAL

Decomposition of Proteins . — Because of the varied compositions of proteins, their decomposition varies considerably and ends in widely differing results. The processes are but little known. A large number of molds, yeasts, bacteria, protozoa, and other organisms are always at hand to attack any protein substances as soon as the death of a plant or animal sets in and the factors that check bacterial activities disappear. Aerobic and anaerobic, psychrophilic and thermophilic organisms may be active. A considerable number of different kinds of enzymes are active in this transformation. The first decomposition products are formed through hydrolysis, the same as in carbohydrate decomposition. The amino acids are the first well-known compounds of protein decomposition; other products are the amides.

Formation of Ammonia . — From here on decomposition proceeds through a large number of intermediary compounds, some of them with very disagreeable odors. The end product of the nitrogen-containing fragment is always ammonia.

Besides the proteins, there are a large number of other nitrogenous compounds in plants and animals, like chitin, quinine, strychnine, morphine, nicotine, etc., and all of these are eventually decomposed and the nitrogenous fragments resulting are composed of ammonia. It must be understood, however, that the various compounds do not decompose with the same ease. Those that generally serve as foods are very easily decomposed; those that function in protection or are waste products decompose with difficulty; and those that are classed among the toxins decompose only under special conditions.

Nitrification . — It is said that the last fragment of protein decomposition, as well as that of other nitrogen compounds, is ammonia. Ammonia may further be transformed into nitrite, through an oxidation process by means of nitrite bacteria. Nitrate bacteria then completes the oxidation of nitrite to nitric acid. Basic substances that may be present will then neutralize the acid, forming nitrates. The nitrates are then again available for plants. The nitrite and nitrate formation proceeds simultaneously in the soil. As a rule, the presence of organic substances is favorable to the nitrifying organisms; and the more humus there is present in the soil the more active are the organisms. In peat bogs, however, nitrifying organisms are not active. In these, there are not enough basic compotmds necessary to neutralize the nitric and nitrous acids formed and not enough oxygen to permit rapid oxidation.

Nitrate Reduction . — There is a large number of bacteria that perform the opposite transformation and reduce nitrates to ammonia. Two steps are necessary in some cases, one set of bacteria reducing to nitrite and another the nitrite to ammonia, but others reduce direct from nitrate to ammonia.

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All humus compounds and other easily oxidizable substances may actively bring about nitrate reduction, and may entirely replace bacterial nitrate reduction in peat bogs. Even when micro-organisms are present it is not always their oxygen requirement that is responsible for this reduction. Many products formed by them are easily oxidized and may bring about nitrate reduction. This is the reason why peaty, swampy, and water-logged soils are poor in nitrates. When such soils are aerated, ammonia is again nitrified.

Amino-nitrogen, Ammonium Nitrogen and Nitrate Nitrogen Assimilation. — A large number of species of bacteria and fungi have been isolated that will transform ammonia, amino-nitrogen, as well as nitrate nitrogen into protein compounds. This is a common occurrence, but it depends on various conditions.

Liberation of Nitrogen. — The liberation of nitrogen is purely chemical and may occur when amides and ammonia have an opportunity to react with nitric acid.

Denitrification. — Denitrification may be defined as the reduction of nitrates by bacteria, involving the evolution of nitrogen gas or nitrogen oxides. It should not be employed to designate losses of nitrogen gas due to the oxidation of ammonia, or the disappearance of nitrates, following their conversion into protein by micro-organisms.

There are a large number of species of bacteria, mostly anaerobic, that can reduce nitrates to nitrites and ammonia; a considerable number are known that cause complete reduction of nitrates with the evolution of nitrogen and nitrogen oxides. Denitrification occurs most often and most actively in soils containing an excess of undecomposed organic matter. They ordinarily grow under aerobic conditions, but they can also thrive under anaerobic conditions, but only when nitrites and nitrates are present. They cannot exist in the deeper strata of peat bogs.

Nitrogen Fixation by Soil Bacteria. — It is well-known that the nitrogen content in ordinary uncultivated soil rich in vegetal matter increases without human interference. This increase is due to the annexation of atmospheric nitrogen, through the agency of micro-organisms.

A number of bacteria have been isolated and grown in nitrogen-free culture solutions where they assimilated free nitrogen. Carbohydrates, such as starch, sugar and cellulose, are necessary as soil ingredients for the existence of such bacteria. Experiments have shown that as much as 53.6 gm. of nitrogen have been fixed per liter of bacterial culture solution.

Nitrogen Fixation by Nodule Bacteria. — It is common knowledge that when crops like grain and corn are raised, there is a loss of nitrogen in the soil, and that when certain other crops are raised, notably clover and alfalfa, the nitrogen content is increased. Experiments have shown

Microscopical Constitution Op Coal

that a cain clover added more than 200 lb. of nitrogen per acre to the soil.

As is well known, the legumes in general grow a large number of nodules or tubercles on their roots and root-hairs. These nodules are filled with rod-shaped bacteria, called bacteria adiciola. These bacteria are capable of fixing nitrogen from the air, which becomes a part of their protoplasm; but how the clover extracts the nitrogenous substances formed is yet unexplained, but as far as known nitrogen fixation always leads to protein compounds in the plant. No other products of assimilation have ever been found.

Wood Decay

In decaying wood, the highly complex components pass into products of decreasing complexity until finally all pass into carbon dioxide (CO2), water (H2O), methane (CH4), and hydrogen (H2). Between sound wood and the final products must exist a series of intermediate products. Wood in peat, therefore, must contain many of these products in various stages of arrest.

Wood decay is accompanied by a very rapid fall in cellulose, while the lignin complex, being far more resistant than the cellulose or not attacked at all, remains almost constant. As decay progresses, there is a very decided increase in the less stable P cellulose, a large loss in the more stable a cellulose and a slight loss of the 7 cellulose. The difference in sound and rotten spruce wood is shown in Table 5.®

Table 6 . — Chemical Composition of Sound and Rotted Spruce Wood

Sound Spruce Contained Per Cent.

Badly Rotted Spruce Contained.

Per Cent.

Cellulose, total

Clftlhilnoe

f 63.36

fi r!Al1ii1nse

y CAlliilose

Pentosan

[ 11.88

Methylpentosan

Ash

Cold water soluble

Hot water soluble

1 per cent. NaOH soluble

7,14 per cent. NaOH soluble

Ether soluble

M. W. Bray and Joseph Staidl: The Chemical Changes Involved during Infection and Decay of Wood and Wood Pulp. Ind, Eng, Chern. (1922) 14,

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In Table 6, the differences in sound heartwood, partly rotten heartwood and more completely rotted heartwood of the Douglas fir is given:*

Table 6. — Composition of Decayed Wood

Sound Wood, Per Cent.

Partly Rotten Wood, 1

Per Cent.

More Completely Rotted, Per Cent.

Cold water soluble

Hot water soluble

Alkali soluble

Cellulose

Acid hydrolysis

Pentosan

Methylpentosan

Methoxyl group

Moisture

Ether extract

Ash

As decay proceeds the cellulose disappears more and more, leaving finally very little or nothing but the so-called human, a product of the original lignin of the lignocellulose proper. Recent experiments with fir wood containing 60 per cent, cellulose, after 6 months rotting contained 26.8 per cent., after 1 year 10.90 per cent, and after 3 years 6.05 per cent. The lignin complex lost about 3 per cent, in 3 years and then remained constant. It must be remembered, however, that wood contains a number of adventitious substances, like fat and waxes and others. These are not decomposed by organisms of decay, as shown in the ether extracts.

The foregoing account and tables are from studies made on materials that were infected with mixtures of organisms. Bray and Andrews® later carried on investigations at the Forest Products Laboratory, Madison, Wis., to show the chemical changes brought about in wood when infected by specific organisms in pure culture. The results are shown in Table 7.

Robert Evstafieff Rose and Martin William lissi: The Chemistry of Wood Decay. Ind. dt Eng. Chem. (1917) 9 , 284.

M. W. Bray and T. M. Andrews: Chemical Changes of Ground Wood during Decay. Ind, & Eng, Chem, (1924) 16 , 137.

Micbosgopical Constitution Of Coal

Table 7. — Analysis of Ground Wood Based on Equal Weights of Sample Analyzed {Per Cent) {after Bray and Andrews)

Sample

Orsanism or Culture No.

Storage Time, Months

Water

Soluble

1 Per Cent. Alkali Soluble

fl

s

Cellulose

a Cellulose

6 Cellulose

7 Cellulose

Pentosan

Methoxyl

Copper No.

Cold

Hot

Sound

60.0 60.5

36. 7.19. 6

Fomes roseus

Fomee roseus

Lentinus lepideus

Peniophora tabacina

5.6,10.4

j

55.4 34.2

Table 7 shows only the amount of the constituents of decayed wood in percentages of the decayed wood itself; Table 8 shows the percentage of the different constituents based on the original dry wood :

Table 8. — Analysis of Ground Wood Based on Equal Weights of Original Sample {Per Cent) {after Bray and Andrew)

Organism or Culture No.

Storage Time, Months

Loss Due to Decay

Water

Soluble

1 Per Cent. Alkali Soluble

Lignin

Cellulose

a Cellulose

$ Cellulose

7 Cellulose

Pentosan

d

Sample

Cold

Hot

??

o

s

u

Q.

o

Sound

9.0'

Fomes roseus

Lentinus lepideus

Peniophora tabaoina. . .

Remaining Residue of Wood or Humus Formation

During the process of decay, lignin does not decay uniformly and probably proceeds very slowly by stages. Few experiments have been carried on and little has been recorded that furnishes any knowledge of the lignin degradation or so-called humus formation.

In consideration of the facts known concerning lignin, lignocellulose and cellulose, it may be assumed that the residue of thoroughly decayed

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Wood is the same as the lignin prepared from wood by artificial means. This reasoning has not been verified by exact chemical means; on the other hand, however, nothing has been furnished to show the contrary.

Bray and Andrews found that when in decaying wood the results were calculated on the original sound-wood basis, the value of the lignin remained practically constant or only a slight decrease may be observed. After one year of storage after inoculation of lignin, a 3 per cent, loss was observed; after three years of storage no further loss resulted. This loss is accounted for by the loss of the methoxyl group, which in this particular case was 2.8 per cent, of the original wood.

, How long the lignin will resist the attack of micro-organisms under favorable conditions is not known. According to certain observations so-called rotten wood and rotten logs in the primeval forests must have been exposed in this condition for several hundred years, yet are still fairly compact. The same forests show that the tree trunks finally do disintegrate to such an extent that the remainder is merely in the form of a dust. How much older these are, it is not possible to estimate. In the peat bog, further decay is checked relatively early.

Thoroughly rotted wood consists partly of water-soluble substance, partly of alkaline soluble substances, and an insoluble residue much richer in carbon. A reliable record has been made by Wehmer. He separated rotten fir wood, Picea exelsa, into the following substances:

Humin I. Cold-water soluble. A brown-black, glistening, hard lac easily soluble in water, extractable with hot water.

Humin II, Hot-water soluble. A coal-like, dull powder, composed of small spherical grains of 1-5 mm. in diameter, extractable with hot water, precipitating on cooling as a brownish gray sediment.

Humin III. Alkali (2 per cent.) soluble. Glistening, brownish black, brittle pieces, unsoluble in water, extractable with 2 per cent, solution of soda as a dark brown solution, coagulating with acids in fluffy flakes.

Humin IV. An insoluble peat-like compact brown residue retaining the woody structure. Table 9 shows the percentage composition :

Table 9. — Composition of Substances in Rotten Fir Wood

Substance

Humin I . . Humin II . Hmnin III Residue. . . Water

I Per Cent.

H2,

Per Cent.

! 6.0

Per Cent.

Zum Abbau der Holzsubstanz durch Pile. Ber,-Deutsh. Chem. GeseL (1915) 48 , 130-134. Rev, KoU , (1915) 16 , 181,

Microscopical Constitution Op Coal

A sample of wood, with a 51 per cent, carbon content, during complete decay yielded (1) 50 per cent, of CO 2 , H 2 O, and some fungal remains; and (2) 50 per cent, of humified wood, with a carbon content of 56.8 per cent. The humified wood was separable into (a) 15 per cent, watersoluble substance with a carbon content of 46.4 to 51.6 per cent., (jb) 35 per cent, alkali-soluble substance, with a carbon content of 64 per cent., and (c) 50 per cent, insoluble substance, with a well-preserved woody structure with traces of cellulose.

Pectin . — Pectin is readily decomposed by micro-organisms. An enzyme, pectinase, first hydrolyses it to arabinose. This sugar is then fermented through the agency of zymase, resulting in some cases in carbon dioxide and butyric acid, and in alcohol, formic acid, acetic acid and acetone in other cases. A number of bacteria have been isolated that will decompose pectin but no other compound of the plant. A number of fungi will also dissolve pectin.

The cells of all plant tissues are cemented together by means of a thin layer of pectin, called the middle lamellae. On hydrolysis of the middle lamellae, the tissues disintegrate into their fibers or cells; fruits in such cases are said to become mushy. The retting of hemp and flax depends on the solution of the middle lamellae by means of bacteria.

Hemi'<cellulose . — The hemi-cellulose, such as pentosans, mannans, and xylans, are also dissolved by a series of bacteria. The hydrolyzing enzyme is xymase. No bacteria has been isolated that will decompose galactan.

How Plants Contribute to the Bog

During every growing season plants grow new leaves, young shoots, flowers, seeds, pollens, and spores; wood and bark are added to the stems, besides, certain secretions such as gums, resins and tannins, mostly products of disassimilation, are deposited in ducts and reservoirs throughout the plants. Also, every year the plants shed the leaves, blossoms, pollens, spores, part of the bark as a natural sequence of the life processes of the plant; twigs, branches, and trees are broken or torn down by the wind, ice, sleet, and snow. Trees or parts of trees die through injury and sooner or later drop in a semi-decayed condition. Many trees, on account of the loose ground they live on, are not able to hold up and gradually lean over more and more until they lie flat on the ground, and sooner or later are buried dead or alive by subsequent debris. Thus, in the long run, an equilibrium is maintained between growth and drop.

The dead material, as long as uncovered by water, undergoes a rapid decay, begun by fungi and maintained by fungi and bacteria. Fungi soon transform these plant parts into a soggy mass and prepare it for the attack of bacteria. As long as it remains exposed to the air, decay proceeds rapidly. Much of it decomposes completely, some of it remains

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in a condition. In this state, much of it crumbles and much of this is transformed into a fine debris. In this condition, the mass is sooner or later covered by subsequent decaying vegetable matter and becomes submerged below the water level. Once in this position, decay proceeds through bacteria alone and very slowly, partly on account of the exclusion of air and partly on account of the antiseptic condition of the mass caused by the decomposition products themselves. Slow changes, however, are taking place in the bog, and even at considerable depths below the surface. This is shown by the change from a more immature peat in the upper strata to more and more mature peat in the deeper strata. Living bacteria are found at all depths of the bogs, and gases, mostly methane, are constantly being given off from the deposit. These bacterial activities deprive the deposit more and more of its oxygen and render it a highly reducing agent.

Differential Rates of Decomposition of Plant Substances

Not all plant substances decompose with the same ease, in fact some do not appear to be attacked at all by agencies of decay while others rot very quickly. The plant components that constitute the living part of the plant, as also the plant foods and reserve substances such as the sugars, starches, and gums, are relatively easily decomposed, and relatively little remains of them during ordinary rotting on the surface. The cell- wall components, also, vary greatly in the ease with which they rot or decompose. The hemi-cellulose, hexoses and pectins, decompose more easily than the cellulose, which are quite resistant. The cuto-cellulose are the most resistant to decay. The largest part, as has already been intimated, is contributed by the wood of plants.

As shown, in rotting wood the cellulose disappears rapidly, while the lignin complex or certain parts of the lignone complex remains; and it is this part that niainl} contributes to peat. From laboratory experiments, it would seem that after three 3"ears of exposure in moist conditions no (or but little) cellulose remains.

Those substances that are here called the "protective substances," are all resistant to agencies of decay. To them belong cuto-cellulose, wax, fats of higher molecular weight, and resins. The cuticles of many plants, the spore exiles and pollen exiles, are largely composed of such substances and undergo but little chemical change. The waste products, in general disassimilation products no longer available as foods, are also not readily decomposed; to these belong the resins, terpins, alkaloids and purine bases. Because these substances undergo little or no decomposition and as those substances that form the bulk of the plant mass undergo considerable decomposition, the former substances remain in relatively very much larger percentages than found in the plant originally. It is thus seen that a selection or an accumulation of the more

Microscopical Constitution Of Coal

resistant substance is going on all the time and the more resistant the less is their loss, and that the more and most resistant substances accumulate proportionately faster than the least and the less resistant. It is another case of the survival of the fittest.

Differential Decay of Different Species

It is well known that certain species of plants are subject to decay much more readily than others. Among the swamp-loving plants, it may be observed that a black ash is decomposed more readily than a spruce or a balsam, a balsam quicker than a tamarack, and a tamarack quicker than a cedar. The black ash is the least resistant and the cedar the more resistant tree to biochemical decay. In the same swamp, a black ash may be decomposed to a debris, while a cedar tree lying beneath it is still hard and sound.

If the different peat-forming trees always grew in a mixed condition, a differential decay would not visibly influence to produce different kinds of peat. But we do not find them growing that way. It may be observed that, because of certain conditions, the kinds of plants growing in a swamp are restricted to one or two species with only a few other species sparingly intermixed. We thus come to speak of a cedar swamp in which by far the most predominant tree is the white cedar, with only a few other species intermixed. Likewise are the tamarack swamps, the black-ash swamps, the bald cypress swamp, the spruce swamp and so forth.

When the peat deposits formed by these different floras are examined, it is found that each has characteristics of its own. The black ash, which is quickly attacked, furnishes a much macerated peat deposit; on the other hand the white cedars furnish a deposit characterized by a large number of tree stems; and tamaracks furnish a well-macerated peat but characterized by its resinous matter.

The foliage of the trees that form the flora of a swamp influence the nature of the deposit as much or more than the nature of the woody parts. The surface layer of a cedar swamp differs widely from that of a tamarack swamp or a black-ash swamp as a result of the difference in the decomposibility of the leaves, and surely the peat derived from them must differ as much.

The exact cause of the difference in durability in wood is not known, but it is quite certain that the chemical composition of the wood is a large factor. It has been shown by Hawley, Fleck, and Richards that woods in which the extracts are the most toxic are also the most resistant to decay. It was also found that the extract of the heartwood

PL. F. Hawley, L. C. Fleck, and C. A. Richards: The Relation between Durability and Chemical Composition in Wood. Ind, & Eng, Chem. (1924) 16 , 699.

Reinhardt Thies8En

is more toxic than that of the sapwood. It has always been supposed that the lesser durability of the sapwood was due to the larger amount of sugars and starch in it, and thus further the growth of micro-organisms. Although this may be a factor, the greater toxic content of the heartwood is probably the greater.

Plant Matters Buried Alive

It has been mentioned that a considerable number of trees recline more and more until they lie flat on the ground and eventually are buried alive. Secondly the root complex of the flora of the swamp, while they never penetrate far into the peat stratum below, living roots remaining relatively near the surface, by the time they die are covered by a considerable amount of debris. Such plant matter evidently does not go through the same phases of decay as those that decay on the surface with complete access of air. Such plant parts, in the first place, will not be macerated, but will be transformed whole. Whether the changes brought about in them through decay in a buried condition differs from that of decay in the air remains to be seen. Decay under such conditions is probably extremely slow. Fungi are excluded at all times and reasoning from the chemistry of wood decay, cellulose fermenting bacteria only can be active, living under strong reducing conditions, fresh peat being a strong reducing agent. We may have here a solution of the origin of mineral charcoal.

Variations in the Degree of Decay and Maceration through Varying

Conditions

If the conditions of water level and moisture in a certain bog were constant throughout its life, the deposit would be uniform in texture, structure, and composition. In a large number of deposits, the natural sequence in the life of a deposit is from an aquatic bog to the woody swamp. To reach the last stage, it has to go through the marsh stage, the sedge stage, the shrub stage, the mixed shrub and tree stage, and finally reaches the permanent tree stage. In sounding such a deposit, each stage is recognizable by the specific kind of peat that was deposited. A number of such deposits are found in the peat regions of Michigan and Wisconsin. Provided that no other cause appears, these bogs pass from an aquatic condition, through the various stages of diminishing moisture until the mesophytic stage is reached, where it will remain. The climax is reached simply by filling up the depression with the debris of its own vegetation. Other causes may modify the conditions. Natural erosion may remove a barrier and thus aid in the drainage, or the eaiiihs surface, including the swamp, may rise gradually changing drainage conditions, or even removing the deposit already established. Artificial drainage is the most common cause today in reversing swamp conditions. In parts

Microscopical Constitution Of Coal

of Wisconsin and Michigan, where the earlier settlers found impenetrable peat bogs, today are found wheat fields, celery fields, and orchards. Ten years ago, Sheboygan Marsh in Wisconsin was an impenetrable peat bog, with a peat deposit about 10 ft. deep; in another ten years, between 6000 and 7000 acres will be transformed into truck fields and orchards.

The opposite transition may also take place. A swamp may begin with the mesophytic wooded stage, and gradually be transformed into the aquatic stage, passing through the same phases as the aquatic to wooden swamp series, in the reverse order, increasing in moisture until finally a typical aquatic stage is reached and finally may be covered up by inflowing mud and sand. This state of affairs may be brought about by a subsiding area of the earth's crust. A good example of this condition is found in the Dismal Swamp of Virginia and North Carolina, with Lake Drumond in its midst, in which the stumps and a few remaining trees bear mute witness of a once woody swamp. In this case, also, each successive stage deposited its characteristic kind of peat, similar to that of the aquatic to mesophytic series; the transitions of course may be gradual and almost imperceptible. In the coal measures, similar transitions are recorded in the earth's strata, as will be noted further on.

Composition of the Peat Bog

From what has been said, it should not be difficult to get a fair idea of the composition of peat in all its varieties. In a discussion of peat, it is essential to take into consideration the different kinds of peat formed under different conditions, as each type of bog gives rise to its characteristic kind of peat. For example, the open-water bog gives rise to a much macerated, mucky peat, the sapropel of Potonie; the marsh furnishes a peat often alluded to as 'lebertorf;" and the tree-covered swamp (Fig. 1) gives rise to the woody peat. These three kinds are set off arbitrarily as types; several other types and every possible intergradation may exist.

The Open-water Deposit

The deposit formed in the open-water bog consists of a slimy ooze, composed largely of the most resistant plant products of plants that lived in and around the bog. Among these are the cutinized coverings of stems and leaves, the waxy and oily content of stems and leaves; seeds and seed coats, pollens and spores. Pollens may be blown in from flora surrounding the bog. Humic or woody plant degradation matters are always present in relatively small, but in greatly varying, proportions. Algal matters do not contribute any appreciable part. Deposits of this kind approach in composition the cannel coals of the older periods.

Ueinhardt Thiessen

Fkj. 1. — Close-up view of peat bog of Wisc'oxstn; foreground is under water; partly ('ovehed tree trunks are shown; hummocks indicate buried TI tEE trunks; is approximately S ft. deep.

Fig. 2. — Close-up view of surface of same peat bog, showing nature of litter ON surface; foreground is partly under water.

Microscopical, Constitution Of Coal

Fig. 3. — Lump op air-died peat, from bog shown in Fig. 1, showing a large

NUMBER OF SMALLER FRAGMENTS OF WOODY PEAT, SOME MICROSCOPIC IN SIZE, EMBEDDED IN THE ATTRITUS. NATURAL SIZE.

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Fig. 4 . — of air-dried peat, from bog shown in Fig. 1 , consisting largely

OF ATTRITUS, CONTAINING A LARGE NUMBER OF SMALL FRAGMENTS OF WOODY PEAT.

Natural size.

Microscopical Constitution Of Coal

The Marsh Peat

The product of the marsh is composed essentially of the same constituents, except that it contains a much larger relative amount of humic matter, and occasionally small fragments of woody matter, fragments of the haulms of sedges, grasses, and seeds. Mosses and lichens may have been prominent contributors.

The peat of this type of bog may be subdivided into various k'nds, according to the predominant class of plants contributing. The mosses, particularly sphagum, may have been the chief contributors; or grasses, or sedges, or both grasses and sedges may have been the maincontributors.

Peat of the Wooded Stvainp

Peat formed by the wooded-swamp type (Fig. 1) is in every analogous to an ordinary lignite, subbituminous or bituminous coal. This kind of peat is, therefore, of greatest interest. The more mature peat begins a foot or so beneath the surface layer, and usually extends to within a short distance from the bottom or may extend to the bottom. This mass consists of the same components as the surface layer, only in a much further advanced stage of decay. Logs or parts of tree trunks, fragments of these and larger parts of branches and roots constitute the more bulky components. Between these are lodged smaller fragments of these same constituents (Fig. 3); all is embedded in what appears like a dark-brown to black mud. This is the attritus; see Figs. 3 and 4.

Matter derived from the woody parts of plants forms by far the largest portion of the ordinary woody peat. It consists of what is ordinarily termed rotten wood. We are today much better informed as to the nature of rotten wood than we were a few years ago.

Chemical Nature of Peat Wood

Laboratory experiments have shown that when wood is inoculated with wood-destroying fungi, only a small percentage of the cellulose of the wood remains after three years, but the lignin of the wood remains nearly constant. If wood is exposed under favorable natural conditions, it becomes the host of a number of different fungi as well as bacteria, and decay proceeds more rapidly. The time of exposure of the plant matter of the sw'amp of both fungi and bacteria in the air is on the whole much longer than three years. It may be assumed, therefore, that the decay of the wood above the surface is quite complete. After the decaying wood is submerged, if any cellulose has escaped destruction, bacteria still continue their activities. It must be remembered that a considerable number of trees recline more and more until they finally lie flat on the ground, still alive, and are gradually covered up alive. These will

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never attacked by fungi, and bacteria alone can act on them. Similarly, the greater proportion of the roots of the swamp flora, although always relatively close to the surface, are buried under a considerable quantity of debris or are even submerged beneath the water and are not subjected to aerial decay but to bacterial decay only. How readily these constituents are attacked and how far the cellulose is destroyed in them remains to be seen. In sounding a bog from top to bottom, it is found that the upper strata still contain some cellulose, but this decreases in amount downward, and in the deeper strata is but sparingly found if at all.

It has always been a question as to what had become of the cellulose. Although cellulose as such could not be found, or but sparingly, in peat wood, could it not have been changed into some residual substance, and if so what was its nature? It is now known that the first decomposition of cellulose is by hydrolysis, and that its first decomposition product is cellobiose, which splits into glucose. Being a good food substance glucose is easily fermented to simpler products. It is also known that the lignin of wood is not decomposed easily either by means of organic enzymes or by chemical reagents, except that it may lose its methoxyl groups. Although it is not known what becomes of the lignin in the end under moist aerial conditions, it is known that enough of it, in fact by far the most of it, escapes decomposition and is finally submerged, where it apparently does not decompose much further. If any further decomposition takes place, we are not as well informed as in the case of cellulose (Figs. 7 and 8).

The hemi-cellulose, pentosans and xylans, starches and gums have also disappeared. The middle lamellse in many cases are still recognizable, in some cases none is visible.

Laboratory experiments also show that the waxes, oils, and resins are not destroyed by micro-organisms; tests on peat bear out this statement. What part of these remain in the wood in natural conditions is not well known. All that is known is that such woods yield certain amounts of soluble substances.

When examined microscopically, thin sections of thoroughly rotted peat wood reveal much foreign matter in the fibers (Fig. 9). Some of these may be identified as gums, waxes, resins, and oils. No exact account has been taken, and all that can be said is that a considerable quantity of foreign matter is commonly found in the cells and fibers of various wood tissues after decay.

Physical Nature of Peat Wood

Mature peat wood is partly soluble in hot water and almost completely soluble in a weak solution of potassium or sodium hydroxide. This yields a dark brown, in dilute solutions, to black, in more concen-

MICHOSCOPICAIi CONSTITUTION OF COAL

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Fig. 6. — Part of thin cross-section op conifer shown in Fig. 5; cell walls are COMPACT AND WELL LAYERED; MIDDLE LEMELLUM IS CLEARLY SHOWN. X 1000.

Microscopical Constitution Of Coal

Fig. 7. — Thin cross-section op fragment of peat wood, such as is shown IN Fig. 3; compare with Fig. 5; cell walls are ragged and tattered and have LOST THEIR EVEN FORM; HYPH.ffl OF FUNGI ARE SHOWN. X 200.

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Fig. 8. — Part of thin section of woody peat shown in Fig. 7; shows cell

WALLS OF ROTTEN WOOD IN DETAIL AND HYPHAB OP FUNGI,* NOTE SHREDDED APPEAR- ANCE; ONLY MINUTE QUANTITIES OF CELLULOSE HAVE REMAINED. X 1000.

Vol Lxxx — 6

Microscopical Constitution Of Coal

Fig. 9. — Thin cross-section of fragment of peat wood, such as is shown IN Figs. 3 and 4. This piece of rotten wood contains considerable non- RESINOUS cell INCLUSIONS; CELL WALLS ARE IN AN ADVANCED STATE OF DECAY AND

cellulose has almost completely disappeared, X 200,

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Fig. 10. — Thin section of carbonized attritious peat; horizontal stride

REPRESENT CUTICLES; ATTRITUS IS COMPOSED LARGELY OP CUTICULAR DEGRADATION MATTER, DEGRADATION MATTER OF LEAP TISSUES, SOME WOODY MATTER, SPORE AND POL- LEN MATTER, AND SOME RESINOUS MATTER. X 200.

Microscopical Constitution Of Coal

trated solutions, which precipitates on addition of acids. This substance is commonly called human, humic acid, ulmin and ulmic acid.

Peat wood no matter how large the fragment may be, has retained its normal cell structure at the time when taken from the bog; the cells are in the natural position and, to a large extent, hold their natural shape. When seen under the microscope, in thin section, the thickness of the cell walls does not seem to have diminished appreciably as compared with sound wood of the same species. The matter composing the cell walls, however, differs much in appearance from that of sound wood. It is loose and granular in structure, although it has retained some of its layering. The middle lamellum is usually present, but may have separated from the main wall (Figs. 7, 8, and 9).

Mature peat wood, when fresh from the bog, is soft and friable, may easily be cut with the spade, is pliable, and fairly plastic, almost like clay.

Under the ultra-microscope, the cell walls are shown to be typical gels. When dried, peat wood hardens into the consistence of hard rubber or bone, and its volume shrinks considerably. When now examined under the microscope, the cell walls have largely collapsed and appear much thinner than when examined wet and fresh from the bog. The mass of mature peat wood has all the characteristics of a hydrogel. This is an important characteristic in consideration of the future coalification. All hydrogels, when dried, change into a hard, brittle, almost glassy, substance; its quality is dependent on its purity.

Attritus

The attritus is the finely divided solid residue of decay and consists largely of parts of plants that resisted complete decay or not attacked at all. It contains, therefore, a large proportion of the more resistant plant products rather than of the less resistant. It is composed of the deadation matter of anything and everything that grew in the bog, and consists therefore of a large variety of substances (Fig. 4). To the naked eye, the attritus appears as a black mud, or as a black jelly-like substance; and when rubbed between the fingers has a jelly-like, slimy feel. When observed under the microscope, however, it is shown to consist of definite and specifically recognizable particles; consisting of bits of plant parts, isolated cells or part of cells, bits of tissues of wood, leaves, bark, roots, bits of tissue of mosses and lichens, fragmentary cuticles, pollens, spores and resinous particles, and some dirt (Fig. 10). These different components vary considerably in proportion from one swamp to the other and from one horizon of the same swamp to another.

The humic matter of the attritus may be derived from the wood, bark, pith, leaves, mosses, lichens, gums, starch pectins, and other carbohydrates. It is thus seen to be of a varied origin. It is largely present as definite particles and but a very small part of it is colloidally dispersed.

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Much of it can, however, be dispersed colloidally by means of certain reagents.

Cuticles of leaves and stems are always present and arc easily recognizable (Fig. 10). They are in the form of smaller or larger fragments and often are finely macerated. This constituent cannot be dispersed colloidally nor is it soluble in ordinary solvents. Spores and pollens also are always present and easily recognizable. This constituent also cannot be dispersed colloidally nor is it soluble.

Resinous matter also is always present in various forms and is easily recognizable. Resinous particles are liberated from rotted and disintegrated wood, bark, and leaves. Like the cuticles, pollens, and spores, resinous matters are not subject to decay, and hence remain constant as based on the original material, and have been concentrated when based on the amount of its residual matter. Resins are soluble by means of various organic solvents, but cannot be easily dispersed colloidally.

Waxes and fats or oils are present but cannot be distinguished readily microscopically, yet they can be extracted by means of various solvents. Besides these constituents, theoretically considered, a considerable number of other plant products must be present, either as original compounds or degradation products, such as of tannins, alkaloids, glucosides, and the purine bases. But they cannot be observed by ordinary microscopic means, and little is known about them in peat. But that plants have contributed these to the coal is clearly shown by the presence of certain decomposition products of coals.

The Microscopic Constitution Of Coals Of Different Ranks And Ages

Coalification Processes

The transformation of the plant substances into peat was largely brought about by fungal and bacterial agencies. The sum of the processes have been called biochemical. As the peat bog was gradually covered up by clays, sand, and silt, the biochemical processes gradually ceased, but the relative increment of the carbon content and the relative decrease in oxygen content begun by the biological agencies continued.

How much longer the biological activities continued after being covered is not known and is an important problem for consideration both as to how long bacteria survive and how long the enzymes secreted by them remain active after their death. Bacteria have been found at all depths (up to 30 ft.) of recent peat bogs. To deposit this amount of peat must have consumed hundreds of years. If bacteria can survive imder such conditions at such length of time, the question normally arises when do they cease to exist and what destroys them? It is also well known that enzymes will remain active under favorable conditions for a considerable period after the death of the organisms giving rise to them. It would.

Microscopical Constitution Of Coal

therefore, also be of considerable interest to know how long the enzymes remain active in the bog after the death of the bacteria themselves.

The further changes brought about in the peat substance after being covered and which continue through the whole series of the coals from peat to anthracite have for short been called coalification.' In recent years, the processes involved have been termed ''dynamochemical," in contradistinction to the biochemical. To show graphically something of the nature of the changes, the ultimate analyses of types of coals in each stage of the series from peat to anthracite are given in Table 10. To this is added that of wood and lignin for comparison.

Table 10 . — Analyses of Coals by Stages of the Coalification Process

Substance

' Per Cent.

1 Ha,

1 Per Cent.

j Oa,

1 Per Cent.

Na,

Per

Cent.

Wood

Lignin (Schwalbe)

lignin (Konig) ;

; 64.85

Lignin (Klason)

Lignin (Fischer & Schrader) i

j 64.70

Peat, wooded, Wisconsin !

; 2 58

Brown coal, Saxony !

Coal, carboniferous lignites, Moscow, Russia

Lignite, Burlington, North Dakota i

lignite, Williston, North Dakota

72.68 !

Subbituminous, Montana

Coal, bituminous, Illinois, Franklin County

Coal, bitiuninous, Upper Freeport, Pa

83.13 ;

7.80 !

Coal, bituminous, Pittsburgh Bed, Bruceton, Pa. . .

Coal, bituminous, Alabama

86.54 !

Coal, bituminous, Somerset County, Pa

88.59 j

Coal, bituminous, .Tioga County, Pa

88.98 !

3.08 :

Anthracite, Schuylkill County, Pa

92.91 !

Ultimate analyses of the successive stages, in peat, brown coal, lignite, subbituminous coal, bituminous coal, semibituminous coal, and anthracite, therefore, show that extensive changes have taken place, the total result of which was a progressive elimination of volatile matters consisting of carbon dioxide, methane, water, and some carbon monoxide, in such relative proportions that there was a continuous larger loss of oxygen than carbon, with a loss of hydrogen that held the relative hydrogen content about constant throughout, except in the higher ranks, where considerable loss is notable.

Causes of Coalification

Practically little is known concerning the causes of coalification. Pressure is usually cited as the principal factor; time also is cited. But it

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should be remembered that time is not a cause, only a factor of duration during which an agent has an opportunity to act. It is believed that slow spontaneous chemical changes are going on in most complex organic substances. During a short period such reactions would be but very slight, but over a period of thousands, or even millions of years, the total result must be considerable. It is possible that the decomposition reactions started in the vegetable debris in peat continues for a considerable time after the bog was covered, possibly together with other catalytic agencies. Under the same conditions, everything else remaining similar, the same results should be obtained in different deposits during the same length of time. Unfortunately there are no cases in which the conditions were the same. But let us consider briefly the time factor.

There are coals near Moscow, Russia, of Lower Carboniferous age, which must be ranked as lignites, of about the same rank as the lignites of North Dakota of Upper Cretaceous age. The German brown coals, of Oligocene age, still younger than the lignites of North Dakota, are only of a slightly lower rank than the Russian coal mentioned. If then the action set up by the enzymes of the biochemical stage, or spontaneous decomposition of the complex organic molecules, continued at all after the bog was covered, it did not continue very long, or the actions are so slow as to make very small differences during the millions of years that elapsed since the Carboniferous ages. Different causes must therefore be sought.

Pressure is generally cited by geologists as the cause. Looking over the field, many phenomena may be cited that appear to prove the assumption. Of the cases cited above, the Russian coals are covered with but a light overburden of rocks, unfolded and undisturbed; the German brown coals are covered with a light overburden consisting of clay; while the lignites of North Dakota are covered with a rather heavy overburden, but the rocks have not been disturbed or folded. Certain coals in the Alps of the same age as the Russian coals, but in rocks much folded and subjected to much earth movements, have been transformed to graphite and shungite. Coals of the Rocky Mountains of about the same age as the German brown coals, and again in rocks much folded, are of high bituminous rank. Following the lignites of North Dakota westward into regions more and more subjected to earth movements and earth thrusts with rocks folded more and more, are coals of the same age and of the same bed, transformed into coals of higher rank, being of high butiminous or even of anthracite rank in the Rocky Mountains. Many cases of like nature can be cited. In every case, such change occurs along areas of increasing marks of disturbance or folding, in rock that forms a heavy overburden. Also invariably coals of high rank, like the anthracite of eastern Pennsylvania, are associated with rocks that have been subjected to folding and earth thrust.

Microscopical Constitution Of Coal

Rocks that have been folded are said to have been subjected to high pressure. There is therefore a good reason to assume that pressure is the factor that caused the devolatilization of coals or the changes of coals from a lower to a higher rank. But when pressure is considered from the standpoint of the physical chemist, the case becomes more complex. That pressure modifies or influences a chemical reaction is known. Pressure also brings about a chemical reaction in some cases when the volume of the products of the reaction are smaller than the original. It may also hasten the reaction under certain conditions, as in explosives and gases under pressure; but here other factors than pressure come in. But coals do not fall under any of these cases. The volume of the products of the reaction in coal is many times larger than the coal itself. Pressure could not have hastened any reaction started by reagents earlier.

Pressure is invariably accompanied by a rise in temperature, therefore, temperature should be considered briefly. When it is desired to hasten a reaction or start a reaction it is common practice to raise the temperature. It is known that rocks under higher pressure and in the act of folding, or where earth movements are taking place, are at a slightly higher temperature than the same rocks farther remote.'® It is also known that, with increase in depth, the temperature rises even in undisturbed rocks. The temperature need not necessarily be high. A temperature only a few degrees higher of one deposit above that of another would show marked differences over a long period.

Loss of Moisture . — Along with the chemical change, there is a simultaneous decrease of moisture from approximately between 50 and 40 per cent., in the brown coals and lignite, to only a few per cent., in anthracite. In peat, the water is largely held colloidally, the human matter being in typical state of hydrogel. With time the water is withdrawn, the mass becomes harder and more brittle as hydrogels do on dessication, the tendency being to develop into a solid similar to hard rubber. The total mass, of course, consists of a mixture of constituents; it is, therefore, not a pure hydrogel and will not transform into the hard solid form as it would if it were pure. The hardness or physical condition of a coal may therefore be accounted for by the colloidal nature of the ingredient matter. It required no high pressure nor high temperature to give it the characteristic physical condition in which coal is found. That it requires no high pressure nor high temperature to transform mature peat into a hard coal-like substance can be demonstrated easily in the laboratory. When thoroughly matured peat is slowly dried while kept under a slight pressure, so as to bring the components in close contact and keep out the air as the water is evaporated,

M. X. Stainier: Isogeotherms and Tectonic Geology. Annates des Mines de Belgique. Abst. Coll. Guardian. (1924) 127, 415.

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it will bo convortod into a hard coal-like substance. Any woody peat wIkui treated with a weak alkaline solution and then left to dry slowly, will also be converted into a hard coal like substance.

Further, by proper means peat may be changed largely into a colloidal solution, which, on evaporation, gradually turns into a gel and, on further drying, into a mass that physically closely resembles bituminous coal. In like manner, brown coal, lignite, subbituminous coal, by proper means, may be brought into a colloidal solution from which it may be reverted by evaporation into mass that in many ways cannot be distinguished from the original coal, the one obvious difference from the original being that it has lost its banding or layering characteristic in coal.

If all the peat mass were in a typical stage of hydrogel, no pressure would be required in order that peat be transformed into a hard coallike substance after gradual elimination of water. But as already stated, peat consists of a mixture of substances, many of which are not complete hydrogels; spaces exist between the different components requiring external pressure to bring the different parts together, and if none is applied on dessication the mass dries into a more or less spongy mass. If, however, but slight pressure is applied, just enough to keep the spaces from filling with air as the water is removed, a hard bony mass results. A heavy overburden should, therefore, have the tendency to produce a solid compact coal.

Effect of Overlying Rocks , — These laboratory experiments are corroborated in nature. The German brown coals have relatively but a light overburden. They are of a loose spongy nature, still much like peat. American lignites of the same age, on the other hand, were provided with a heavy overburden and have been subjected to considerable pressure. This resulted in a compact dense black coal termed lignite, in contradistinction to the German brown coal. Microscopically the German brown coals and American lignites do not differ essentially; the kind of components are quite similar in each, their origin was therefore quite similar. Their ultimate analyses generally does not differ much, yet in some ways, such as outward appearance and physical structure, they differ considerably. With the chemical changes and the changes in moisture content, there has also taken place a gradual change in physical condition of the coal.

All constituents of peat are colloids in one form or another; the humic components in particular are in a state of hydrogel. That means that relatively a large amount of water is present as an inherent part of the mass. Water is so closely associated with the peat substances that it cannot be said where the one begins and the other ends as a part of it. The solid colloidal particles composing the gel are relatively far apart; this is characteristically seen under the microscope. As the elimination of water proceeds, these particles are brought closer and closer together

Microscopical Constitution Of Coal

through internal pressure. In lignites, still containing as much as 50 or 40 per cent, water, each ultra particle of coal matter must be surrounded by a film of water which is, however, so thin that it is not visible under the microscope, and is therefore not apparent. Yet the ultimate coal particles are still relatively far apart. The mass is still loose in texture but not porous in the usual sense, but is soft. In the subbituminous coals, where water has been eliminated still further, the ultimate particles have been brought still closer together, and the mass is correspondingly more compact. In the bituminous coals, moisture has now been reduced to within between say 3 and 8 per cent. The water in the coal under such conditions, or in other words the moisture surrounding each ultra particle, can no longer be present in minute droplets or films but can only be present in a molecular state in order to be uniformly distributed. Yet the ultimate particles, although now much closer together than in peat or brown coal, are still relatively far apart, but the spaces between these can no longer be filled with water but must be filled by gases.

Change in Physical Appearance after Loss of Moisture , — Parallel with the loss of moisture, is to be noted a change in the physical appearance of coals. Lignites have a characteristic granular appearance under the microscope. The granular condition changes more and more into a glassy or vitreous condition as coals of higher rank are reached and reaches a maximum in the coking coals. Coking coals, as a rule, have a characteristic vitreous appearance.

At the end of the coalification process, the various constituents that entered into the peat deposit, though still recognizable, are now in a chemically and physically changed condition, as may be accounted for by biological and coalification processes.

Composition of Coal

All the components recognizable in peat may be traced with certainty from the peats through the whole series of coals such as brown coal, lignites, subbituminous coals, bituminous coals, and anthracite. These components in peat, to repeat, may be summed up as follows:

1. The larger components derived from the woody parts of plants, such as stems, branches, roots, more or less whole or in larger fragments (Fig. 3).

2. The smaller components derived from the same plant parts but more highly fragmented (Figs. 3 and 4).

3. The attritus is composed of (a) finely macerated matter derived from the woody parts of plants; (6) finely macerated matter derived from other carbohydrate plant substances like pith, cortex, bark, leaf-tissues, gums, etc.; (c) cuticular matter; (d) spore and pollen matter; (e) resinous matter; (/) waxy and fatty matter; {g) other degradation matter; and (Ji) mineral matter (Fig. 4).

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The larger pieces corresponding to peat wood are abundantly found in the brown coals and lignites and are easily recognizable as such, either microscopically through thin sections or macroscopically (Figs. 11 and 12).

In the lignites, they are recognized as black, glistening, more or less lenticular masses. They are generally spoken of as 'bright coal." Generally their outward appearance betokens that of woody fragments. When examined microscopically in thin sections, no doubt remains that they actually represent pieces of wood. Being derived from wood, they are called anthraxylon (Fig. 12).

Samples of typical earthy brown coals from the Riebeck mine in Germany were recently examined by the author. These samples showed that they differed in no respect in composition and origin from American lignites (Fig. 11). In the subbituminous coals, anthraxylon is likewise prominent and easily recognizable as woody components (Fig. 13). They are here, however, thinner and more compact; in other words, they have been more compressed or flattened. The subbituminous coals offer a fortunate transition stage from lignite to bituminous coal. This provides a means to recognize components definitely in the bituminous coals, although without this transition the anthraxylon is easily and clearly recognized in the bituminous coals (Fig. 14). From the general appearance and banded nature of anthracite, it has long been assumed that anthraxylon is also present in these. Recent methods of polishing and edging have definitely proved this assumption to be correct.

The smaller or more fragmentary woody component of peat can also be traced easily and definitely from one end of the series to the other. These are called smaller anthraxylon components. Their origin and structure differ in no way from the larger (Figs. 15, 16, and 17).

The smaller anthraxylon strips and the attritus together ordinarily comprise the dull coal (Figs. 18, 19, and 20). But when a number of the smaller anthraxylon strips are packed closely together with none or but little attritus between them, they also constitute bright coal (Figs. 21, 22, and 23).

The thickness of the anthraxylon units varies greatly in any coal. In general, their thicknesses decrease with the rank of the coal, being most massive in the lignite, where they have suffered the least compression, and where they may be six inches or more in thickness, and thinnest in the anthracite, where they have suffered the most thorough loss of volatile matter and compression. But in any coal all conceivable sizes and thickness are met with, from those many feet long, several feet wide, and several inches in thickness to a microscopic size. Some coal beds are composed of a large proportion of anthraxylon, these are anthraxylous coals; in others the proportion is much smaller and the attritus forms the larger part of the coal; these are attrious coals. In some, these components are largely quite thick; in others, like the Pittsburgh bed, they are mostly relatively thin.

Microscopical Constitution Op Coal

Fig. 11 . — Thin cross-section of anthraxylon of earthy brown coal from

[llEBECK MINE, GERMANY,* STRUCTURE IS THAT OF A CONIFER,* CELL WALLS OF FIBERS IRE FAIRLY WELL PRESERVED THOUGH CONSIDERABLY COMPRESSED; ANNUAL RINGS 3F TREE ARE WELL SHOWN. X 200 .

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Fig. 12. — Thin cross-section of anthraxylon of lignite from Wilton, N. Dak.; autumn wood is well preserved while spring wood is in more advanced STAGE OF decay; BLACK PATCHES AND HEAVY BLACK LINES REPRESENT RESIN. X 200.

Biicroscopical Constitution Op Coal

Fig. 13. — Thin ceoss-bbction op anthbaxylon op subbituminous coal prom Montana; autumn wood is paiblt well preserved, spring wood is in more

ADVANCED STATE OP DECAY; THE HASS IS MORE COMPRESSED AND MORE COMPACT THAN THAT OP LIGNITE SHOWN IN FiG. 12. X 200.

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Fig. 14. — Thin cross-section of anthraxylon of bituminous coal from THICK Freeport bed; woody structure includes considerable resin, shown WHITE. X 200.

Microscopical Constitution Of Coal

Fig. 15. — Thin cross-section of dull coal of brown coal from Riebeck MINE, Germany; thin strips of anthraxylon embedded in attritus; attritus is composed of woody degradation matter, cuticular matter, spore and pollen matter, resinous matter, and charred woody matter, shown black. X 200.

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Fig. 16. — Thin cross-section of dull coal op lignite from Sheridan, Wyo.;

THIN strips op ANTHRAXYLON ARE SHOWN EMBEDDED IN ATTRITUS; ATTRITUS IS COM- POSED OF WOODY DEGRADATION MATTER, MUCH CARBONIZED MATTER, SOME SPORES AND POLLENS, AND A SMALL AMOUNT OF RESINOUS MATTER. X 200.

Vol. Lxxi. 7 .

Microscopical Constitution Of Coal

Fig. 17. — Thin section of dull coal from a bituminous coal from thick Freeport bed; thin strips of anthraxylon, one of which contains well-preserved STRUCTURE, ARE EMBEDDED IN ATTRITUS; ATTRITUS IS COMPOSED OP WOODY DEGRADATION MATTER, SPORES, CARBONIZED AND SOME CUTICULAR MATTER. X 200.

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Fig. 18. — Thin cross-section of dull coal of a bituminous coal from thick Freeport bed; larger part consists of attritus with but a few thin strips of anthraxylon; attritus is rich in spores. X 200.

Microscopical Constitution Of Coal

Fig. 19. — Thin cross-section of dull coal of bituminous coal, Upper Freeport BED, CaNNELTON, Pa., SHOWING STRIPS OF ANTHRAXYLON; ATTRITUS IS COM- POSED LARGELY OF WOODY DEGRADATION MATTER, RELATIVELY FEW SPORES, AND SOME RESINOUS MATTER. X 200.

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Fig. 20. — Thin cross-section of bituminous coal, Upper Freeport, with number of thicker strips of anthraxylon interlayered with an attritus RICH in spores; there is about an equal proportion of anthraxylon and attritus IN this layer, but it still may appear as dull coal. X 200.

Microscopical* Constitution Of Coal

Fig. 21. — Thin cross-section op bituminous coal, Pittsburgh coal; layer

CONTAINS larger PROPORTION OF THIN ANTHRAXYLON STRIPS THAN ATTRITUS AND appears as BRIGHT COAL. X 200.

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Fig. 22. — Thin cross-section of bituminous coal from Pratt bed, Gorgas, Ala.; layer is composed largely of thin strips of anthraxylon and woody DEGRADATION MATTER AND APPEARS AS A TYPICAL BRIGHT COAL. X 200.

Microscopical Constitution Of Coal

Fig. 23. — Thin cross-section of bituminous coal, Redstone bed, Madison, Pa.; larger part of layer is composed of strips of anthraxylon and woody degradation matter and has appearance of bright coal. X 200.

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Fig. 24. — Thin choss-section of anthbaxylon of a bituminous coal, Upper Freeport, withhesins included in cells. X 200.

Microscopical Constitution Of Coal

Fig. 25. — Thin ckoss-section op anthraxylon of a lignite from Sheridan, Wyo.,

Including Resin. X 200.

Fig. 26. — Thin cuosjs-section of attritus of brown coal from Riebeck mine, Germany; attritus contains all constituents found in peat, lignite, subbituminous, AND bituminous COAL, BUT IS NOT AS COMPACT AS THAT OF OTHER COALS.

Microscopical Constitution Of Coal

Fig. 27. — Thin cross-section fo attritus from a North Dakota lignite;

COMPOSED LARGELY OF WOODY DEGRADATION MATTER, SOME POLLEN MATTER, RESIN- OUS PARTICLES, CUTICLES, CARBONIZED MATTER, AND PYRITE. X 200.

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Fig. 28. — Thin cross-section of attritus op subbituminous coal from Kem-

MERER, WyO. X 200.

no

Microscopical Constitution Of Coal

Reinhardt Thiessen

30. — Thin ckoss-section of attritus of a bituminous coal, Low'er Kittanning bed, rich in spore matter; spores are characteristic spores of Lower Kittanning bed.

Microscopical Constitution Of Coal

Remains of the original woody structures arc preserved in all anthraxylon; in some they are exceptionally well preserved, in others but faint traces are left. The state of preservation again varies, in general, directly with the rank of the coal. The most and the best-preserved structure has been retained in the lignites, and from here drop off until the anthracites are reached. The state of preservation is, however, not always determined by the metamorphism of the coal. In many cases, it was probably determined during the first part of the peat stage.

Original and natural cell contents, such as resin, are commonly included (Figs. 14, 24, and 25). Resinous matters are not decomposable and have retained much of their original bulk, and while the woody fragments enclosing them have largely decomposed, the resinous contents have been concentrated in them, and often form the larger part of the anthraxylons. This is particularly well known in the lignites, in which resin-bearing conifers were the main contributors.

The attritus constitutes the embedding medium and in a cross-section appears between the thinner anthraxylon as layers alternating with it. The attritus and the smaller anthraxylon strips together constitute the dull coal, but the attritus alone also has the appearance of a dull coal. Cannel coal, for example, is all attritus and has a dull appearance.

Although a complex substance, the attritus as a whole, and the main constituents composing it, can be traced from one end of the series to the other, clearly and definitely. It consists largely of the rubbish or refuse that escaped complete decay. It would be expected, therefore, to find in it besides the woody degradation matters, many of the substances more or less resistant to decay. To these substances belong the cuticles or outer coverings of leaves, stems, and branches; and the waxy fatty and resinous coverings, pollen grains and spores; also resinous, waxy and fatty contents of cells and tissues. Besides these, there is a long list of substances in plants that are more or less resistant to decay, such as tannins, alkaloids, terpenes, camphors, and others. Many of these are so finely dispersed throughout the plant, and now through the attritus, that they escape observation under the microscope. Many of these are probably absorbed by the coal matter itself (Figs. 10, 26 to 30).

Summary

In a study of coal, all evidence points to the fact that coals have been formed in a similar manner as have the peat beds of today; with

For supplementary illustrations on origin and composition, the reader is referred to the following articles by the author: Structure in Paleozoic Bituminous Coals. Bur. of Mines BvU. 117 (1920) — Compilation and Composition of Bituminous Coals. JfU, GeoL (1920) 28, 185-209 — Constitution of Coal Through a Microscope. Proc, Coal Min. Inst. Amer. (1919) 34r-35 — Recent Developments in Microscopic Study of Coal. Proc, Coal Min. Inst. Amer. (1920) 88-119. Reprinted in Coal Age (1920) 16, 1183-1189, 1275-1279 and 19, 12-15 — The Origin and Constitution of Coal.

Reinhardt Thiessen

that as a basis, the study of peat is essential. In turn, for the study of peat, considerable knowledge of the chemistry of plants and of decay is essential.

The components and products of plants have been outlined, a brief review of the mechanism of decay given, and the decay of wood reviewed.

The purpose of this paper is to show that all the plant products went into the peat bog, but an elimination of certain components and a concentration of others took place through decay; that cellulose, although constituting the bulk of the plant body, did not contribute materially to the bog in verification of theory, and that many of the byproducts of coal distillation are recognized in the plant products of the living plant.

The plant parts and plant products remaining at the close of the biochemical processes are distinctly recognizable; but little is known of the chemical composition of most of these. The ultimate analysis shows that during the biochemical processes, a relatively larger loss of oxygen than carbon took place, resulting in a relative increase in carbon and a relative loss in oxygen while the hydrogen content remained constant. This relative progressive change of the carbon and oxygen content began during the biochemical stages, and continued during the successive changes into brown coal, lignite, subbituminous coal, bituminous coal, and anthracite. These changes are called coalification.

All of the components of peat, definitely recognizable, may be traced clearly and definite through the whole series of coals from brown coal to anthracite.

The larger woody components of peat, when coalified, partake of a bright shiny appearance and have popularly been called bright coal. Such units being derived from wood are called anthraxylon. The smaller fragments of woody matter in peat, when coalified, also partake of a bright shiny appearance and are easily visible in the coals at close examination or Tvith a hand lens. These have the same origin and the same structure as the larger components and are called the smaller anthraxylon. The attritus of peat, on coalification, partakes of a dull appearance and gives rise to dull coal.

Coal comprised of a mixture of the smaller anthraxylon and attritus constitutes a dull coal, the dull coal of popular usage. A number of smaller anthraxylon constituents when including but a relatively small

Proc. Wyoming Hist, and Geol. Soc. (1924); also to the Origin of CJoal, by White and Thiessen, with a chapter by Davis on formation of peat. Bur. of Mines BvU. 38 (1914) — Microscopic Study of the Freeport Coal Bed, by Thiessen and Vorhees. . 2, Carnegie Inst. Tech. (1922) — (Correlation of (Coal Beds in the Monongahela Formation, by Thiessen and Staud. Bull, 9, Carnegie Inst. Tech. (1923) — Correlation of Coal Beds in the Allegheny Formation, by Thiessen and Wilson. , 10, Carnegie Inst. Tech. (1924).

Franz Fischer und Hans Schrader: Enstehung und chemische Struktur der Kohle. 2d. ed. Verlag von M. Gerardif, Essen, 1922.

▼Ol. Lxxx. — 8

Microscopical Constitution Of Coal

amount of attritus also comprises a bright coal. The terms bright" coal and ''dull" coal are merely relative terms. Anthraxylon and attritus, on the other hand, are definite terms.

Discussion

Edward C. Jeffrey,* Cambridge, Mass. — Do I understand that the charcoal found in recent lacustrine deposits is due to bacterial action?

Reinhardt Thiessen. — Yes; secondarily because bacteria need oxygen, this deprives peat of its oxygen which then becomes a reducing agent.

Edward C. Jeffrey. — How is it then that in a recent deposit of that kind there were charred and uncharted branches of trees intermingled with one another, all subject to the same influence under water cover? I find it difficult to understand that situation otherwise than as the result of charred twigs and uncharted.

Reinhardt Thiessen. — I still have my troubles with that theor}".

Ralph H. Sweetser, f Columbus, Ohio. — This past year I examined "mother coal" in the No. 2 gas seam, in West Virginia, and in the No. 6 and No. 7 coal seams in Kentucky. I do not think there is any resemblance between the two. It was stated this morning that possibly the partings in coal came from volcanoes; is it not possible that the carbon itself might have been deposited in the same way on top of the coal seam?

Reinhardt Thiessen. — All the charcoal that I have examined shows plant structure, even small fragments found in the thin sections. They are not what may be called amorphous carbon, such as is produced by natural gas when burned in contact with a cold surface.

David White, J Washington, D. C. — This hypothesis to account for fusain carries the idea of smothered decomposition. A difficulty lies in the occasionally great thinness and the great extent and the frequency of occurrence of the fusain partings. The same troubles attend Doctor Ashleys explanation.

Reinhardt Thiessen. — Although we hear so much about putrefaction and different kinds of decay, there is only one kind. Bacteriologists recognize, of course, anaerobic and aerobic decay, the difference being that aerobic decay can take place in free oxygen while in anaerobic decay the oxygen is not freely accessible; but as far as chemical decomposition is concerned the result is the same. There is also to be dis-

Professor of Botany, Harvard University, t Assistant to First Vice-president, American Rolling Mill C"o. t Senior Geologist, U. S. Geological Survey.

Discussion

tiiiguished between hydrolysis, splitting of tlie molecule into soluble compounds, and fennentation, in which the split products are further decomposed to furnish energy in the bacteria. Bacteria live on many insoluble substances. These they first split into soluble parts, which then diffuse into their bodies where they are digested.

Edward C. Jeffrey. — The author has shown the tops of peat bogs. Obviously he had in his mind what others have called the landing stage of a low moor, that is a moor that was originally water and later was covered by forests. Investigations of the United States Geological Survey (or the Bureau of Mines, I do not recall which) show that 90 per cent, of the vegetable accumulations in the United States that have been investigated are laid down in open water. In other words, they are not of the nature that the author has described. Thomia has come to the same conclusion in Germany.

The author has shown side by side on the same slide, dark resin and light colored resin. Of course the geological age would have a good deal to do with the interpretation made of the slide, but the capacity for producing and continuing resin internally was developed only lately. The earlier plants were not able to produce resin in their cells. Any occurrence of resin, other than in Paleozoic forms inside cells, would be highly under suspicion.

In one section shown there were two remarkable things. One was the materials of resin inside the cells, w'hich would be impossible; the other, that the resin, in the same proportion, was quite black in one case and light colored in the other. I have examined a great deal of amber from Mesozoic deposits and it is a very uniform substance and is always light colored.

Reinhardt Thiessen. — The black appearance on the screen of these resinous parts is not necessarily as dark in the section as it would appear; to bring them out color screens were used.

Edward C. Jeffrey. — A great many of the things interpreted as resin were simply the uncollapsed tracheids. I have often seen them. They are individual tracheids that do not collapse.

Reinhardt Thiessen. — I do not believe that that is possible; I have gone into that matter thoroughly and I am convinced that those are actually resin inclusions.

Edward C. Jeffrey. — All resin cells in Mesozoic wood are dark colored.

David White. — The paper emphasizes two or three outstanding points. One is the lack of initial differences between a peat of a given type and that of a lignite, subbituminous or bituminous coal, or anthracite of the same type.

Microscopical Constitution Of Coal

The author shows splendid technique in bringing out the cell structure in material in which it has not so successfully been shown before. He leaves no escape from the fact that most coals have a great amount of wood in them and are laid down where a great amount of woody vegetation grew, more or less of which decayed according to the conditions prevailing from time to time. Consequently, the deposit varies as to the concentration of resins and other decay-resistant materials.

The Micbostbucttjbe Op Coal

The Microstructure of Coal

By Clarence A. Seyler* Swansea, Wales

(New York Meeting, February ,1925)

The technical difficulties of cutting thin sections of coal for examination by transmitted light have hitherto restricted the investigation of the important subject of the microstructure of coal to the few possessed of the requisite skill and time. Apart from this, the method fails with anthracites and other coals rich in carbon, owing to the opacity of the material. Occasional use of the method of polishing a surface, with or without etching, has been made, but it was not until Winter published an account of his results that attention was seriously directed to the method.

In Maj, 1923, a specimen of dull anthracite came into my hands; I tried Winter's method on it and the presence of megaspores and other vegetable structures became clearly visible. A preliminary notice was published by me; but I soon abandoned the use of Schulze's solution, having found that a mixture of chromic and sulfuric acids gave far better results. In the meantime Turner and Randall, in America, had independently developed the method of flame etching, as applied to anthracite, with great success. I have spent a year studying the method of chromic etching, which gives excellent results with bituminous coals and cannels, as well as with anthracite. For anthracites, I have used the chromic method and Turner's method of flame etching, whichever was the more convenient or as a check one on the other.

The polishing is done, according to metallurgical practice, by the use of a polishing machine and successively finer emery paper, followed by polishing on cloth moistened with a suspension of levigated green oxide of chromium, and a final rubbing on ''selvyt" (a cotton velvet polishing cloth) moistened with alcohol. The polished sample is examined by reflected light with a % and in. objective. Bituminous coals usually show considerable structure, and even anthracites show it faintly in places. The sample is then etched by immersion in a boiling solution made by adding 10 c.c. of concentrated sulfuric acid to 30 c.c. of a saturated solution of chromic acid; enough water is then added to dissolve

Public Analyst.

1 Fvd in Sci. Prac, (1923) 2 , 21 and 78.

Fuel in Sd. & Prac. 1923) 2 , 217.

The Microstructure Op Coal

any precipitated chromic acid. The solution is boiled until chromic acid begins to separate and the polished sample is then immersed in the liquid, which is kept biHling for a few minutes. The sample is then removed, cooled, washed, dried, and very slightly rubbed on selvyt moistened with alcohol. Anthracites require from three to five minutes, bituminous coals usually less than one minute. The etching can be carried out in successive stages.

The method appears to offer several advantages over that of sectioning. It is applicable to all kinds of coal and is quick and easy. So far as my experience goes, it shows the presence of structure as well as the thinnest sections. Indeed, since very thin sections are difficult to prepare, whereas in the polished specimen one has a section of infinitesimal thickness, it is possible to use very high magnifications and to bring out details of structure that otherwise would escape us.

The interpretation of the results, especially owing to the difference between transmitted and reflected light, requires experience. As Stopes and Wheeler have said, we must educate a new race of paleobotanists trained to perceive in minute fragments of cells "a recognizable plant structure." To this task of self education, my endeavors have been chiefly devoted, before entering on the systematic study of the Welsh coal field. Miss M. Evans, working under the direction of Doctor Wheeler, is applying the method to the Yorkshire coal field with very promising results.

The chief aim of the investigation is the attempt to infer from the results observed: (1) The plant tissues from which the coal has originated or which have contributed to it. The chief tissues are distinguished by marked differences of chemical composition and resistance to decay. Thus in woody tissue one might expect the pectocelluloses (such as constitute the middle lamellae of cells) to decay rapidly, while the lignocellulose would persist longer. The cortex would probably behave somewhat differently but the cutinized and suberized portions, such as spore exiles, cuticle, and cork are richer in hydrogen and would probably resist decay longer and yield a different coal. We wish to know whether we can infer from the observed fragments, the tissues (xylem, cortex, cork, cuticle, or spore exiles) that have contributed to the coal and trace their effect on the composition and characters of the coal; (2) the nature of the processes, biochemical or chemical, by which the plant cells have been reduced to their present condition.

Why has the structure been preserved in certain cases and disappeared in others? Where contents are observed in the cells are these the original contents (resins, etc.) or were the walls thickened in life (sclerenchyma) or is the filling post mortem? How far are we dealing with the original

Monograph on the Constitution of Coal. London, 1918, H. M. Stationery Office.

Clarence A. Seyleb

cell substances and their contents or to what extent, if any, is coal a "replacement phenomenon' as suggested by Hickling, and the structure pseudomorphic? Why are some cells fusainized" and others not? These questions must be regarded, so far as British coals are concerned, as largely unsettled.

My efforts, up to the present, have been chiefly devoted to the interpretation of the structures found, that is to say, the problem of inferring from them the kind of cell or of tissue that they represent. I give here some examples of the way in which the cell, in general, may be degraded in Welsh coals.

P'fragmented Cells

Cellular fragments of a characteristic shape and disposition are frequently found, chiefly in fusain lenticles, but also embedded in bright coal and passing into it; these are shown in Fig. 1. The fragments are bounded by arcs, or bows, and the linear arrangement is sometimes, as in this case, well marked. Such fragments are familiar to the petrologist, and structure of this kind is called by Mugge's term bogen" structure, that is arc structure. The structure is highly characteristic of comminuted vesicular or cellular rocks, such as lava, tuffs of basalt, etc.

The obvious interpretation is that the structure represents fractured secondary tissue, which might be either xylem or cortex. This interpretation has, however, been disputed, and the fragments called algal cells," so that it is important to be certain of the interpretation. The steps which prove that it really is fractured secondar tissue may be seen in the following illustrations.

Fig. 2 shows bogen structure in anthracite. In Fig. 3, there is a similar ''bogen" structure, with the peculiarity of one or two dots in nearly every fragment. The interpretation is given, by Fig. 4, from an adjoining portion of the same coal; this shows that the dots are the intercellular spaces left, as is common in certain plant tissues, at the angles where cells touch each other. Complete hexagonal cells may be seen amid the fragments. The same thing is shown in Fig. 5 from a different Welsh anthracite. In Fig. 2, close inspection will reveal faint lines extending from the angles of the fragments and meeting near the center. Prolonged etching, as in Fig 6, brings them out more clearly; Turner's method also shows them. Their interpretation is made clear by Fig. 7, which is from a Scotch anthracite. Here the intercellular spaces are joined by dark lines, which clearly represent the middle lamellae of the cells. That the cells were elongated is proved by Fig. 8, which shows them cut obliquely with the middle lamellae quite distinct.

That the cells were those of secondary tissue, either xylem (wood) or periderm (cork) is thus certain, but there is no evidence to prove which.

The Uicrostructure Of Coal

Periderm, in which the cells were disposed in lines, was well developed in most of the coal plants. In some cases of bogen structure, there is an

Fig. 1. — Bogen structure in an- Fig. 2. — Bogen structure in anthrathracite; etched with Schulze's sol- cite; chromic etched. X 450. unoN. X 100.

Fig. 3. — Bogen structure in anthra- Fig. 4. — Complete cells, showing

cite; chromic etched. X450. intercellular spaces, same sample as

IN Fig. 3; chromic etched. X 450.

indication of medullary rays, which would prove it to be wood. In others, this evidence (or that of pitted tracheids) is absent and it is possible thRt the persistent occurrence of well-marked intercellular

Clabencb A. Setleb

spaces, as in Figs. 5 and 4, may indicate cortical tissue. This is a point that I hope to investigate further.

Fig. 5. — Bogen structure and com- Fig. 6. — Bogen structure, showing

PLETB CELL IN WeLSH ANTHRACITE; MIDDLE LAMELLAE; CHROMIC ETCHED. CHROMIC ETCHED. X 450. X 450.

Fig. 7. — Cells uncompressed and com- Fig. 8. — Elongated bogen struo- PRESSED IN Scotch anthracite; flame turb in Welsh anthracite; flame etched, X 450. ETCHED. X 450.

Unpbagmented Cells

Bogen structure may be seen passing into coal in which the cells are unfractured, as in Fig. 9 (Welsh anthracite). In Fig. 10, the bogen.

The Microstructure Of Coal

structure has given place to unfractured' cells linearly disposed. In this case, the lumens of the cells are greatly reduced. Whether this

Fig. 9. — Passage from fractured to Fig. 10.— Unfractured cells in Welsh

UNFRACTURED CELLS IN AVeLSH ANTHRA- ANTHRACITE,: CHROMIC ETCHED. X 450.

cite; chromic etched. X 450.

Fig. 11. — Cells SHOWING iNTEBCELLU- Fig. 12. — Complete cells in Welsh

LAB SPACES and MIDDLE LAMELLiB IN ANTHRACITE; FLAME ETCHED. X 450. Scotch anthracite; flame etched.

represents a fragment of sclerenchyma in which the walls were so thickened as to reduce the lumens to mere points, or whether the cells have

Clarence A. Seyler 123

been filled post mortem by a colloidal substance which became bright coal, is an important but unsettled point. In this case, there are no

Fig. 13. — Welsh anthracite; flame Fig. 14. — Welsh anthracite; flame ETCHED. X 450. ETCHED. X 450.

Fig. 15. — Medullary rays and woody Fig. 16. — Woody tissue and medal-

TISSUB IN cross-section FROM FOSSIL LARY RAYS IN CROSS-SECTION OF FOSSIL stem; CHROMIC ETCHED. X 100. STEM; CHROMIC ETCHED. X 450.

middle lamellse to be seen, nor did flame etching reveal them. It looks as though the middle lamellsB had early decayed. When they were filled by a dark matrix, they are easily seen on etching and may be

The Micbostbuctube Op Coal

the most persistent feature in the survival of the cell. In other cases, they have been filled with bright coal or compressed in a plastic state and vanished.

The same applies to the lumens. Where they have been filled with a dark matrix they survive. When fractured, the juxtaposition of the arcs of the fragments form highly characteristic figures, consisting of alternate lenticular spaces joined by curved lines. Such spaces may be seen in Figs. 5 and 9. They often occur in a mass of structureless coal and may be the only survival of structure, but they may be sufficient to showthat we are dealing with what was once secondary xylem or cortex

Fig. 17. — Woody tissue in longitudi- Fig. 18. — Spores in cross-section

NAL- SECTION OF FOSSIL STEM, SHOWING OF WeLSH ANTHRACITE (DULL COAL) ; TBACHEIDS WITH BORDERED PITS; CHROMIC ETCHED WITH ScHULZE's SOLUTION. X 50. ETCHED. X 450.

In other cases, the lumen may disappear, either by compression or filling with a bright coal-matrix, and the middle lamellae alone survive as dark lines. If intercellular spaces are present they may survive as dots, or we may have a series of lines and dots; this may be observed in Figs. 7 and 11. The compression has closed the lumens and reduced them to faint lines, while the middle lamellae and intercellular spaces remain as parallel lines with dots at regular intervals.

Occasionally the cell structure is extremely well preserved, as in Fig. 12. The cell walls may be seen on close inspection to be perforated, and I think we have here anoblique section of scalariform tracheids.

From the question of the survival of cells in general, we pass to the question of the identification of tissues. Of these the most important

Clarence A. Seyler

is woody tissue. To identify this we have to rely on three characteristics: (1) the occurrence of pitted tracheids, (2) the presence of medullary rays running at right angles to the tracheids and often containing resin, and (3) the presence of wood parenchyma or cells resembling the rays in form and contents, but parallel to the tracheids.

The pitted cells may sometimes be observed in anthracite; Fig. 13 is an example, in Fig. 14 we have the remains of scalariform pits. The medullary rays are often hard to trace, but they seem to survive in some cases as lines, often showing bogen structure.

A very instructive specimen was given me by Doctor Wheeler last July, which we propose jointly to investigate chemically as well as microscopically. It consists of a fossil stem in which the pith has been replaced by shale or stone, around which there is a layer of bright bituminous coal over an inch in thickness. Fig. 15 shows the appearance of a transverse section under a low magnification. The medullary rays are seen as dark lines thrown into waves in some places hy compression. A part of the same section magnified 450 diameters is shown in Fig. 16. Note the characteristic and lenticule spaces left by the displaced fragments of the large cells of the medullary rays. A longitudinal section, magnified 450 diameters, is shown in Fig. 17. In this, the long tracheids are seen with what, I think, are clearly 'bordered pits, such as are found in coniferous wood. The large cells of the rays are cut transversely.

The characteristics of cortical tissue are not so clearly made out, but cortex can certainly give rise to bright coal. I have some flattened stems of sigillaria and lepidodendron with a very thin bright coaly layer marked by the leaf bases and scars. I have succeeded in polishing and etching these and showing the cellular structure in places. The cells have large intercellular spaces and middle lamellae, but are not filled with a dark matrix, and are difficult to photograph. So in anthracite showing marks of the bark of lepidodendron I have observed nearly complete cells, with lumens and intercellular spaces joined by middle lamellae. The further investigation, it is hoped, will throw light on the characters of bright coal formed from cortical tissues and not from wood.

A word may be said concerning the dull coal. It 'contains comminuted fragments of all sorts of tissue. Spore exiles are frequently but not always present. Megaspores in anthracite are shown in Fig. 18. Dull coal, however, appears to exist in very small quantity in Welsh anthracite. When it occurs, it is often called "anthracite cannel" or pitch-like coal, but it resembles cannel only in appearance. If Thiessen is correct in attributing bright coal to larger fragments of wood (or perhaps one should say if this should be true of British coals) it has evidently an important bearing* on the origin of anthracite. I have forborne to discuss this question or indeed to attempt to make any

THE MICBOSTBtrCTUBE OP COAL

generalizations until more data have been accumulated by the systematic examination of the British coal fields. I have made a beginning of such a study of the Welsh coal fields, but an enormous amount of work remains to be done. The method of etching by reagents, however, has, I think, established itself as a powerful instrument for the microscopic investigation of coal.

Microscopical Structure Op Anthracite

Microscopical Structure of Anthracite

By Homer G. Turner,* Bethlehem, Pa.

(New York Meeting, February, 1925)

Coals, other than anthracite, have been so thoroughly studied under the microscope during recent years, that we now know what kinds of plants and what parts of plants form the bulk of lower rank coals from peat to bituminous coal. The microscope has also shown the state of preservation of such vegetation as well as the nature and distribution of products of plant decay. These and further details have been ascertained mainly through the employment of two methods of attack, section cutting and maceration.

Anthracite has failed to respond to these methods, so well adapted to the study of lower rank coals and, therefore, has been neglected by investigators to such an extent that there is much doubt as to its microscopical characteristics. The object of this paper is to lift anthracite from its realm of obscurity by demonstrating the wealth of microscopical detail that is revealed when reflected light is used on a properly polished and etched surface and, further, to show the relationship between anthracite and bituminous coal.

Technique

The method adopted in this investigation is similar to that described in an earlier paper. Because of slight modifications recently made, the process is again described. It consists, briefly, of etching a polished surface of coal with heat. Although pieces of various sizes and shapes are used, blocks of coal about 2 or 3 cm. square take the most uniform polish and are large enough to be handled with ease. Larger pieces can be used if one has the equipment for polishing them and they may be desirable when one wishes to study some particular form that extends for some distance through the coal. Large surfaces, however, require greater care in polishing and etching; for this reason, they are not recommended for ordinary work.

Assistant Professor of Geology, Lehigh University.

H. G. Turner and H. R. Randall: A Preliminary Report on the Microscopy of Anthracite Coal. JnZ. of OeoL (1923) SI, 306.

Microscopical Structure Op Anthracite

Small blocks are cut from the coal by means of an ordinary hacksaw. Two surfaces, one parallel to the bedding and one at right angles to it, are ground to planes. All sharp edges are beveled slightly to prevent pieces from breaking off and scratching during the subsequent smoothing. These plane surfaces are then polished to remove saw marks and scratches.

The methods commonly used in polishing metals may be employed. The object is to obtain a scratchless surface with the minimum of time and effort. The method that yields best results consists of first grinding on a revolving iron lap with medium-sized carborundum powder and water; next grinding by hand on plate glass, using a paste of flour ahmdum and water; and then polishing by rubbing upon a piece of fine canvas or similar cloth stretched on a flat block, using again a paste of flour alun~ dum and water. The final buflSng is done by rubbing the washed and dried specimen on broadcloth with diamantine, or on wet broadcloth with magnesium oxide. All rubbing is done in a circular path, with the exception of the final few motions at each stage; these should be in one direction so one can tell when all the scratches produced by one rubbing are removed by the next. The polished surface thus produced may not be free from scratches, but these will not be objectionable if the final buffing has been done in one direction so that the scratches are easily recognized by their position. On laminated surfaces, the final polishing and buffing should be across the layers and not parallel to them.

The specimen is placed in a drying oven over a Bunsen burner and heated from room temperature to about 220° C., to remove moisture and to obviate splitting of the surface as the result of sudden heating during the etching process. After this temperature has been maintained for about an hour, the specimen is removed with warm forceps and the polished surface immediately brought to a red heat by applying the oxidizing blowpipe flame at right angles to the face. A differential oxidation is thus produced, which reveals the structure without destroying the polish.

Different coals and different layers in the same coal may etch at different rates, -making it necessary at times to warm and etch repeatedly to bring out the greatest detail. If the coal splits badly when being etched, it must be immersed in clean dry sand with only the polished surface exposed, heated to about 300° C., and etched in place using a blast lamp.

The etched coal is studied with the metallographic microscope, using vertical illumination from a carbon arc. A good working objective is one giving a magnification of from 150 to 200 diameters.

Banding of Coal

All ordinary anthracite, on close examination, is found to be more or less laminated and composed of layers differing from one another in color, luster, texture, mode of fracture, and thickness; Fig. 1. In general.

Homer G. Turner

brilliant jet-black layers alternate with bright black or gray bands, in which are embedded thin sheets of dull material resembling charcoal. The brilliant layers consist of lenticular masses embedded in the bright gray to black coal. They vary in thickness from a few microns to a centimeter or more, and correspond to the layers in bituminous coal that

Fig. 1. — Joint face of anthracite, of Pennsylvania age, from the anthracite REGIONS OF Pennsylvania. Lump shows several flattened jetlike stems, appearing on face of coal as brilliant black bands; these brilliant bands

a, AS WELL AS DULLER PORTIONS fe, IN WHICH CAN BE SEEN FINE LAMINATIONS, ARE IN ENTIRE AGREEMENT WITH ORDINARY BITUMINOUS COAL. NATURAL SIZE.

have been called, by various authors, ''bright coal," "glanz," and 'anthraxylon." The bright bands are thicker than the brilliant jet-black ones, although, on close inspection, they are shown to contain many thin sheets of the brilliant black coal and thin sheets of dull material. These bright bands correspond to the layers in bituminous coal that have been termed "dull coal," "mat/' and "attritus,"

YOL. liXXI. — 9

Microscopical Structure Op Anthracite

The brilliant layers are more compact than the duller ones and possess a more perfect conchoidal fracture. Where they are thick, the broken surface often shows rounded or oval fracture forms. Some varieties of anthracite appear, at first glance, to be composed wholly of the brilliant coal, revealing their various laminse only on careful examination. Other

Fig. 2. — Fragment of wood embedded in granular mass of debris composed OF MUD, macerated PLANT MATTER, AND FRAGMENTS OF MANY KINDS OF PLANT

material; highly compressed condition of the wood is shown; sharp crack

ACROSS WOOD SHOWS BRITTLE CONDITION OBTAINED BEFORE HARDENING OF DEBRIS WHICH FILLS THE CRACK. FrOM BeD No. 5, CaMERON CoLLIERY, ShAMOKIN, Pa.

varieties seem to be composed largely of the bright material, in which are embedded only occasional lenses of brilliant coal.

Mineral charcoal is abundant in almost all anthracite. Cleaving coal parallel to the banding exposes charcoal-covered surfaces in every specimen that shows distinct lamination. In fact, it is almost impossible to

Homer G. Turner

find a square inch of laminated coal that does not show charcoal either in thin sheets or lenses. On the other hand the varieties that are poorly laminated and almost uniform in luster contain little charcoal. The absence of distinct lamination is no doubt due, in part, to the paucity

Fig. 3. — Wide piece of wood showing, in one portion o, flattening to such

AN EXTENT THAT THE WOOD STRUCTURE IS ALMOST OBLITERATED, WHILE PRESERVING WOOD STRUCTURE IN ANOTHER PORTION 6, ALTHOUGH THE FIBERS HERE ARE HIGHLY COMPRESSED. FrOM LOWER PART OF BeD No. 5, CaMERON CoLLIERY, ShAMOKIN,

Pa. X 140.

of dull charcoal. In addition to the thin sheets of charcoal so commonly found in the bedding planes, one finds occasional charcoal lenses several inches in thickness, composed of crisscrossing chips 2 cm. or more in length and 1 cm. in width. Detached chips of these dimensions are also encountered with the coal bands warping around them.

The above megascopic description of anthracite, aside from the luster which is on the whole much brighter, applies equally well to bituminous

Micboscopical Structure Op Anthracite

coal. In fact, it would be difficult to distinguish between anthracite from Pennsylvania and bituminous coal from Illinois were it not for the difference in luster.

The bright layers in bituminous coal have been shown, by the microscope, to consist of wood fragments of various kinds in varying states of

Fig. 4. — Cross-section of wood appearing as a brilliant band in the coal;

WALLS OF WOOD FIBERS HAVE BEEN FOLDED AND COLLAPSED ALTHOUGH NOT GREATLY

fractured; whole section appears brilliant under microscope showing no

BLACK DULL MATTER, SUCH AS IS SEEN IN FiG. 5. FrOM LOWER PART OF BeD No. 5

Cameron Colliery, Shamokin, Pa. X 140.

preservation. The duller layers of bituminous coal are likewise shown to consist of a mass of finely macerated plant matter containing many kinds of tissues, plant cells, fibers, cuticles, resinous matter, pollen grains, spores, and mineral matter. In this mass of debris are also found small bright lenses of woody matter with sheets and chips of dull mineral charcoal. To show the true relationship between anthracite and bituminous

Homer G. Turner

Fig. 5. — Cross-section of wood showing fractured, somewhat bent, and

TELESCOPED CELLS WITH SOME BLACK LUSTERLESS MATERIAL ABOUND CELL FRAG- MENTS; BRITTLENESS AND PRESENCE OF DULL BLACK MATERIAL SUGGESTS CRUSHED CHARCOAL, ALTHOUGH AS IN FiG. 2, THE BRILLIANT WOODY FRAGMENTS HAVE BECOME BRITTLE BEFORE WHOLE COAL MASS WAS HARDENED; MANY FRAGMENTS OF THIS NATURE ARE FOUND IN ANTHRACITE. FrOM CaMERON CoLLIERY, ShAMOKIN, Pa. X 235.

Fig. 6. — ISomewhat oblique cross-section of wood from a small strip op

BRILLIANT COAL,* CELLS ARE SO WELL PRESERVED AND SO LITTLE FLATTENED THAT IT suggests carbonized wood made DENSE BY AN INFILTRATION OP PUTRIFICATION PRODUCT SOLUTIONS. FrOM FoRGE SPLIT OF THE MaMMOTH BED, NaNTICOKE, Pa.

Microscopical Structure Of Anthracite

coal, it is necessary, therefore, to reveal the microscopical characteristics of those components of anthracite that are so obviously duplicated megascopically in bituminous coal.

Brilliant Layers, or "Anthraxylon"

The brilliant layers of anthracite, when examined under the microscope, are found to be derived from pieces of wood, such as limbs, stems,

Fig. 7. — Part of Fig. 6 showing great detail revealed by method of treatment DESCRIBED IN THIS PAPER; NOTE THE DELICATE DUMBBELL-SHAPED MEMBRANE WITHIN CELLS AND ELLIPTIC MARKINGS SURROUNDING SMALL KNOTS ALONG CELL

Walls. X 1000.

twigs, and roots. Wood structure has been preserved in many of them, although it is absolutely lacking in the majority. The cells range from almost perfect forms to forms that have been greatly flattened. Most of the bands seem to have been greatly compressed. In Fig. 2 is shown

Homer G. Turner

Fig. 8. — A section crosswise to bedding showing plicated but little flattened WOOD fiber; this again may represent densified charcoal. From Primrose bed, William Penn Colliery, Pa. X 235.

Fig. 9. — Section shows wood fiber much contorted or possibly scalariform material; perfect preservation shown again suggests hard carbonized material. From Primrose bed, William Penn Colliery, Pa. X 235.

136 Microscopical Structure Op Anthracite

a typical brilliant band, greatly compressed yet showing distinct wood texture. A break in the strip shows that this piece of wood became brittle before the ground mass in which it was embedded. Fig. 3 is a broad brilliant band that shows the transition from well-defined wood texture to almost structureless material. This photograph is of partic-

FiG. 10. — A LARGE, WRINKLED SPORE EXINE FOUND IN DULLER LAYERS OF ANTHRACITE

FROM Pennsylvania. X 235.

ular importance for it shows that the woody matter may be so flattened that it appears homogeneous. Most of the structureless bands will show wood grain on their sides or ends if examined throughout their length and width. It seems logical, therefore, to assume that the brilliant bands which are absolutely structureless are the result of extreme compression. Such structureless bands are not uncommon in certain Enish bituminous coals, where they have been named "vitrain. Fig. 4 shows a condition sometimes met, where the cells have been crushed and folded. Figs. 2 to 4, then, show the usual appearance of the brilli ant

Homer G. Turner

bands, making clear also why some of the bands seem structureless because of great compression.

The brilliant bands in Figs. 6 to 9 show such perfect structure that they suggest pieces of wood which were not as plastic as the average. These fragments may represent partly carbonized wood or carbonized

Fig. 11. — Largb spore exiles from duller layers op coal; markings on the

SPORES ARE PROBABLY LINES OF DEHISCENCE. FoUND IN PENNSYLVANIA ANTHRACITE.

wood that has been thoroughly impregnated with the putrificationproduct solutions during subsequent immersion in the bog.

As in bituminous coal, the woody matter forms the largest part of the deposit. Aside from the pronounced woody lenses mentioned, small chips, single cells, small groups of cells, and other woody products are found in the mass of debris designated here as bright coal.

Bright Coal, or 'Attritus'

This material is a complex granular ground mass, composed of a great number of constituents derived from various parts of plants

Microscopical Structure Of Anthracite

together with mineral grains and substance with the appearance of mud. Some of the easily recognized things embedded in this ground mass are spores, megaspores, cuticles, former resinous matter, pith, plant fibers, plant cells and parts of cells, finely macerated woody matter, and mineral grains; Figs. 10, 11, and 12 show the types of megaspores observed. A

Fig. 12. — View of the ground mass showing a strips of brilliant structureless WOOD, h LARGE SPORE EXINE, C FORMER RESIN BODY, AND SMALL FRAGMENTS OF PLANT DEBRIS INCLUDING MICROSPORES. FrOM BeD No. 5, CaMERON CoLLIERY,

Shamokin, Pa. X 140.

macerated fragment of wood containing round res'n bodies is shown in Fig. 13. In Fig. 14 is shown a longitudinal section of the primary wood of a lepidodendrid surrounded by plant fragments of various kinds. Fig. 17 shows carbonized groups of vascular bundles surrounded by cuticles and strips of wood showing good cell structure, although greatly flattened.

Homer G. Turner

All these forms, and many others too small to show in the photographs, but clearly visible under the microscope, have their counterparts in the corresponding bands of bituminous coal.

Dull Layers — Carbonized Matter

The carbonized matter of coal has been called charcoal,' mother of coal," and 'fusain." That there is a great amount in anthracite is

Fia 13 . — Section crosswise to bedding; this section through the duller LAYERS shows A SOMEWHAT MACERATED WOOD FRAGMENT CONTAINING ROUND BODIES which are PROBABLY VESSELS FORMERLY FILLED WITH RESIN OR GUM. FrOM PRIM- ROSE BED, William Penn Colliery, Pa. X 235.

indicated by the foregoing megascopic description. This material varies in hardness and texture and, possibly, in composition. Most of it shows good plant structure, being structureless in rare cases only. Figs. 18 and 19 represent cross-sections of large fragments of material that, to the unaided eye, lopk like fragments of ordinary charcoal. One piece (Fig. 18) is 'so soft that it crumbles readily in the fingers; the

Microscopical Structure Op Anthracite

thin walls of the perfect cells show the reason for this behavior. The other piece (Fig. 19) is so hard that it can just be scratched with the finger nail. The reason for this superior hardness is shown in the much thicker cell walls and component bright bands of hard coal material. In both of these fragments the cells are devoid of filling. Fragments of other charcoal-like material were isolated and found to be too hard to be scratched with the nail. Under the microscope, these hard fragments

Fig. 14. — section tabough the duller layers showing a longitudinal

SECTION OP PRIMARY WOOD OP A LEPIDODENDRID a) NOTE DELICATE SCALARIFORM

STRUCTURE. From Bed No. 5, Cameron Colliery, Shamokin, Pa. X 140.

show crushed and fractured cells, as illustrated in Fig. 5. It is suggested that this particular material represents carbonized wood which had been densified by infiltration of products of vegetal decay and further hardened by compression. It can be seen that in the bright coal (Fig. 4) the cells are warped and crushed, while in Fig. 5 they are crushed and fractured. In the duller portions of the coal, carbonized fragments are also found having perfect cell structure, with the cells filled with dull structureless material; these are represented by Figs. 20 and 21.

The charcoal-like materials are similar in that they show almost perfect structures. This would suggest that they escaped the jelly stage of the other materials in the bog. Difference in thickness of cell walls and of cell filling may indicate differences either in stages of carbonization or oxidation before burial, or in original composition, or in behavior after burial.

Homer G. Turner

Conclusions

It is evident, from the foregoing, that anthracite responds readily to the method of treatment herein described. The photographs show that very delicate microscopical details are made clearly visible. It has been shown further that anthracite is composed of the same kinds of organisms

Fig. 15. — Strips of brilliant structureless wood a, flattened cells 6,

WARPED AND FRACTURED CELLS C, AND FIBERS OF PRIMARY WOOD OF A LEPIDODBNDRID d.

From Bed No. 5, Cameron Colliery, Shamokin, Pa.

and materials found in bituminous coal; that these organisms and their parts are in the same proportions as they are in bituminous coal; and also that these organisms are in a similar state of preservation, except for the greater abundance of structureless bands produced by intense flattening of wood components.

Microscopical Structure Of Anthracite

Discussion

E. S. Moore,* Toronto, Ont. — These papers should end the difBculties some people have in accepting the opinions of most geologists that there is really no difference between bituminous coal and anthracite in nature of deposition and physical constitution. The suggestion that

Fig. 1 ( 5 . — ibobably a TKAivaviiiBSii; view oe bkimaby woody tissues of a species

OF LEPIDODENDKON SHOWING sc ALARIFORM STRUCTURE; NOTE UNUSUALLY THICK CELL WALLS, GIVING THE APPEARANCE OF FRUIT STONE STRUCTURE. FrOM PENNSYLVANIA ANTHRACITE,

the anthracite of Wales is different from that of America seems to indicate that some of the Welsh scientists are loath to give up the idea that the origin of the Welsh anthracite cannot be explained, as we explain it in America, by influence of pressure. I would like to ask if the author has found any marked difference in the spore content, so far as his studies have gone between the Pennsylvania anthracite and the Pennsylvania

Professor of Economic Geology, University of Toronto,

Homer G. Turner

bituminous coal, and also whether in the attempt to apply this microscopical study in the correlation of the anthracite seams, his efforts have met with much practical success.

Edward C. Jeffrey, Cambridge,* Mass. — There is a distinctive value in having more than one method of studying anthracite. Etching, whether effected by chemicals or by flame, is a much more rapid method

Fig. 17. — Vascular bundles o surrounded by laf cuticle b with compressed WOODY FRAGMENTS C BORDERING THE WHOLE. SPECIMEN FROM FoRGE SPLIT OF

Mammoth bed, N anticoke, Pa. X 100.

for getting results, but the thin sections will give a clearer idea of the organization of anthracite.

Reinhardt Thiessen,! Pittsburgh, Pa. — Doctor Seyler has proved that beyond any doubt. The idea has been formed that it is very difficult to make thin sections. This is not so difficult; we have made as many as eighteen thin sections in a day and if you can make eighteen

Professor of Botany, Harvard University, t Research Chemist, Bureau of Mines.

144 Mickoscopical Structure Op Anthracite

surfaces by his method, you are doing pretty well. It has also been said that it is impossible to make a thin section of brown coals; recently I have made several dozen thin sections of brown coals.

H. J. Rose, Pittsburgh, Pa. — It is very easy to find mother-of-coal structure in metallurgical coke; a single cut section may show ten or twenty fragments.

Fig. 18. — Isolated fragments of friable charcoal showing simple and

PERFECT CELL STRUCTURE; CELL WALLS ARE THIN AND CELLS EMPTY. FRAGMENT WAS SO FRAGILE THAT IT HAD TO BE BOILED IN BALSAM AND XYLOL BEFORE POLISHING IN REGULAR way; ETCHING WAS NOT NECESSARY TO BRING OUT STRUCTURE SHOWN.

Compare with Fig. 19. From thick lens in Mammoth bed stripping near Mt. Carmel, Pa. X 120.

James F. Kemp, New York, N. Y. — About ninety years ago, a Professor Bailey, of the Military Academy at West Point, when sitting before his grate fire, noted that a thin film of ash revealed traces of plant structure.

David White, Washington, D. C. — The methods of sectioning carbonized vegetable debris for microscopical study, brought to such perfection by Doctors Jeffrey and Thiessen, open the way to the investigation of the morphology of a wealth of carbonized or coalified plant remains

Homer G. Turner

previously baffling the student. They should lead to great discoveries in the mutual relations and evolution of the plants of all periods. The revelation in microscopical detail of the morphological secrets of the anthracites is now made possible through the modes of treatment developed by Seyler, Turner, and others.

Clarence A. Seyler, Swansea, Wales (written discussion). — A comparison of the results obtained by the author for American anthracites with those obtained by me for Welsh anthracites (partly by his

Fig 19. — Isolated fragment of charcoal showing almost perfect cell STRUCTURE WITH THICKER CELL WALLS THAN SHOWN IN FiG. 18. ThIS PIECE WAS HARD ENOUGH TO TAKE A GOOD POLISH WITHOUT BOILING IN BALSAM MIXTURE; CELLS ARE EMPTY AND STRENGTHENED HERE AND THERE BY BANDS OF BRILLIANT STRUCTURE- LESS COAL a; NO ETCHING WAS APPLIED TO THIS SPECIMEN. FrOM CaMERON CoLLIERY

Shamokin, Pa. X 140.

method and partly by that of etching with chromic acid) shows a close similarity between them. Figs. 4, 5, and 9 show fragmented cells ("bogen structure") similar to those illustrated in my Figs. 1 to 6, and his interpretation of them as fragmented woody tissues agrees with mine.*

*The Microstructure of Coal; see p. 117.

Vol. Lxxi. 10

Microscopical Structure Of Anthracite

Figs. 6 and 7 show what the author describes as delicate dumbbellshaped membranes within the cells and elliptic markings surrounding small knots along the cell walls.' Comparison with my Figs. 11 and 12 will show, I think, that the elliptic markings are the intercellular spaces and the knots deposits of pyrites or other extraneous matter within them.

Fig. 20. — Carbonized wood showing original cell laminae. Remarkable

PRESERVATION MAY BE DUE, IN PART, TO SILICEOUS FILLING SHOWN BY GRAY AREAS WITHIN CELL WALLS, ALTHOUGH SOME CELLS ARE FILLED WITH BLACK, LUSTERLESS CARBONACEOUS MATERIAL,* NOTE DELICATE INTERCELLULAR SPACES. FrOM FoRGE

SPLIT OF Mammoth bed, Nanticoke, Pa.

The double perforated lines joining the intercellular spaces are the outlines of the middle lamellae, as in my Fig. 12. The dumbbell-shaped spaces are the remains of the lumens, squeezed in the center, the cell walls being either very thick or partly filled with a gelatinized matrix, which has subsequently become bright coal. Fig. 21 may be compared with

Homer G. Turner

my Figs. 7 and 11. The middle lamellae, and intercellular spaces of the uncompressed cells are clearly visible. Supplementary photographs will be found in another publication. While I was in Pittsburgh, Doctor Thiessen gave me some photographs of a German brown coal. The resemblance in every detail to Fig. 11 in the article just above cited, is marvellous.

Fig. 21. — Cells of xylem or phloem of a vascular bundle; this is a section

THROUGH A DULL CARBONIZED KNOT. SoME CELLS ARE PARTLY FILLED WITH SMALL GRAINS OF PYRITE, WHICH DO NOT SHOW IN PHOTOGRAPH. BlACK CENTERS ARE DULL CARBONACEOUS MATERIAL. FrOM FoRGE SPLIT OF MaMMOTH BED, NaNTICOKE, Pa.

I take this opportunity of acknowledging cordially the great kindness of Doctor Thiessen and all the American coal experts whom I met during my recent visit to the United States and to express on behalf of myself and British colleagues, our pleasure at the opportunity afforded us, by the Institute, of exchanging ideas.

A. C. Noe, Chicago, 111. (written discussion). — Some time ago, the microscopical structure of bituminous coal was thoroughly investigated

® Clarence A. Seyler: The Microstructure of Coal. Fuel in Sd, & Prac, (1925)

4 , 56.

Microscopical Structure Of Anthracite

by Doctor Thiessen. Today, we are presented with a most interesting study of anthracite and it is to be hoped that somebody with equal ability will soon take up the microscopic examination of lignite.

There are a few excellent publications on the microscopy of coal that should be brought to the attention of mining engineers.* ®

The article by Booth shows how the microscopic study of coal pays from a commercial point of view. The author divides coal into three classes, all of which can be quickly determined with the microscope. They are: coals of a woody tissue, which swell considerably on heating and form a very porous coke; coals with a predominance of spore coats and microspores which are practically non-coking; and the non-coking long-flame cannel coals. During the War, new sources of coal in Great Britain had to be tapped and coals were accepted or rejected on microscopical evidence alone; little or no chemical analysis and no large-scale tests were run. This was a great saving of time to the laboratory staffs. Jeffrey has written for the general public that is interested in coal — its origin and its many other aspects. The book contains also much valuable information for the geologist and botanist. It is generously illustrated and can be considered the best popular treatment of the subject in the English language. Potoni's book,® written in German, discusses the structure composition and origin of coal for geologists and is the most exhaustive up-to-date handbook on coal petrography.

Professor Turner is the first author who has specialized on anthracite.

A. L. Booth: The Microstructure of Coal from an Industrial Standpoint. Jnl. Royal Microscopic Society of England (June, 1911).

® E. C. Jeffrey : Coal and Civilization.

® Robert Potoni: Petrography of Coal. Berlin, 1924.

Coal In Relation To Coke

Coal in Relation to Coke

By Edward C. Jeffrey,* Cambridge, Mass.

(New York Meeting, February, 1925)

The use of coke in metallurgy, to any important degree, dates from the middle of the 18th century. Its utilization came most opportunely for European civilization. The forests of Europe, except in the most remote and inaccessible regions, had been largely fed, in the form of charcoal, into the smelting furnaces. For a hundred years — the middle of the 17th to the middle of the 18th century — there was a stationary condition of population corresponding to the exhaustion of European forests. This situation, which was particularly evident in Great Britain, was due to the fact that the forests had been depleted and the practical utilization of coke had not begun.

The coking industry is essential for our metallurgical industries, which in turn are basal to healthy economic progress. But coke is of great importance, not only on its own account, but for its byproducts, which enter fundamentally into all the arts of peace and war. The dyestuff industry and the manufacture of explosives are intimately connected with one another, as was shown by the recent war. The subject of coking coal, therefore, is well worthy the serious attention both of practical industry and the scientific investigator.

The most valuable coking coals, from the metallurgical standpoint, are derived from the coals of highest ranks. Coals, for example, that have a carbon ratio of from 70 to 80 per cent, yield the most valuable coke for the blast furnace. The difliculty of investigating these coals, however, is great, for they are rather friable and delicate and possess a high carbon content, which makes them difficult to manipulate. They present, on account of their high carbon content, a considerable degree of opacity when examined, in thin sections, under the microscope. The tenderness of structure and blackness of such high-grade coking coals as those of Connellsville and the Pocahontas region make them extremely diflScult to investigate.

Two of my colleagues, who are taking part in this discussion, will describe the valuable results that have been reached by studying coal by the methods of the mineralogist. Doctor White and Doctor Thiessen have studied the structure of coal as determined from thin sections that

Professor of Botany, Harvard University.

Coal In Relation To Coke

have been polished on the petrographers grinding lathe. Professor Turner, on the other hand, has investigated the stnicture of anthracite.

Fig. 1. — Vertical section op oil shale Tasmanite showing presence op numerous PLATTENED SPORES AND OP TWO THAT HAVE NOT SUPPERED PLATTENING.

Fig. 2. — Vertical section op a typical cannel coal prom Bluegrass, Ky.,

SHOWING PRESENCE OP LARGE NUMBERS OP SPORES, A DARK MATRIX, AND A LIGHTER COLORED MATERIAL, WHICH REPRESENTS WOOD NOW DEVOID OP STRUCTURE.

the most highly carbonaceous of all carbonic minerals except graphite, by a highly ingenious method of polishing and subsequent etching with

Edward C. Jeffrey

heat. My own investigations have been carried on by still other methods. It has seemed to me that the processes employed, by the biolost, in the study of plants living and extinct, would, with proper modifications, reveal the structure of coal better than any other means. It has taken a number of years of experiment to justify this belief, but the results are

Fig. 3. — End of a partly charred branch of a conifer from the American

Cretaceous.

Fig. 4. — Other end of branch shown in Fig. 3; this end has escaped charring.

entirely conclusive for it is now possible to view the intimate organizations of coals of every rank, grade, and description with the highest powers of the microscope. This possibility has not existed in the past and, as a consequence, works dealing with coal lack adequate illustrations of its structure. That situation is likely soon to be remedied. I have supplied a large number of illustrations for recent textbooks dealing with

Coal In Relation To Coke

geology, more particularly with the subject of coal. It would be out of place to describe the technical detail of these methods here, particu-

Fig. 5. — Fragment of wood from coal showing effect of charring in preservation OF WOOD structure; upper part is charred and lower has not undergone THAT process.

Fig. 6. — Vertical section of a coal ball from Lancashire, England, showing

Organization Of A Petrified Concretion In Coal.

larly as they have been stated in a memoir now being published by the American Academy of Arts and Sciences.

Edward C. Jeffrey

At present charcoal is still employed for smelting certain sorts of iron but, from the limited supply, its use is very restricted. It is proposed, in this paper, to show that coke bears an interesting relation, in origin, to the charcoal it has so completely replaced. The investigations of recent years have shown that coals consist, outside of their ash content, of three main materials more or less modified by water action, heat, and pressure. These constituents are present in different proportions in different coals and their relative abundance determines the general character of the coal. In certain coals, known as oil shales and cannels, the reproductive parts, or spores, of fernlike seed plants are present in large numbers. In many oil shales, spores greatly predominate over every other constituent; in cannels frequently they are much less abundant. Such coals yield large quantities of hydrocarbons, both gaseous and liquid, when subjected to distillation, either naturally or artificially. Coals of this type are usually characterized by a curved fracture and dull appearance, in contrast to the prismatic fracture and glistening aspect of coals of the bituminous and anthracitic types. The spore coals are an important source of petroleum and, consequently, occupy an outstanding position in the activities of the present age as the internalcombustion engine is actuated by their products. Coals of this type, in addition to the spores which are nearly always well preserved, even if much flattened by pressure, have a dark matrix which is penetrated by light only in sections 0.0001 in. thick or even thinner. As this material is entirely structureless, it is impossible to make more than a plausible surmise as to its nature. Judging, however, from the organization of accumulations of the present age, which resemble in general structure oil shales and cannels, it is highly probable that this dark matrix, which is so commonly present in spore coals, represents the more perishable parts of plants such as gelatinous cell walls, etc.

The third constituent of coals is wood. This is often extremely abundant and may exclude, in some cases, the spores and dark matrix that predominate in the spore coals, known as oil shales and cannels. The coals of this type, instead of having a conchoidal or curved fracture and a dull aspect, break up into prismatic fragments and are conspicuous for their glistening appearance. These glance or glistening coals supply us with the types known as bituminous coals and anthracites. In these the three constituents described are of different colors. The spores are golden yellow, the matrix when present is black, and the woody constituents have a rich brown hue. The general aspect of a thin section of coal, consequently, presents a striking and even gorgeous combination of colors, when examined by transmitted light under the microscope.

The general subject of the organization of coal has been dealt with by Doctor White and Doctor Thiessen, and the structure of anthracite by Professor Turner. It is possible, accordingly, to confine this paper to the

Coal In Relation To Coke

Fig. 7. — Vertical section op coal surrounding the coal ball; the raw

MATERIALS OF THIS COAL CONSISTED OP WOODY FRAGMENTS OF PLANTS AND HAVE ENTIRELY LOST THEIR STRUCTURE EXCEPT WHERE THEY HAVE BEEN PETRIFIED, AS IN

Fig. 6.

Fig. 8. — Gross aspect op a fragment op coal showing transition from

BITUMINOUS coal TO CANNEL; THE BITUMINOUS IS UPPERMOST AND THE CANNEL COAL BELOW.

Edward C. Jeffrey

composition of coking coals in relation to their organization and origin. Fig. 12 shows the organization of coking coal of high rank from Connellsville, Pa. The coal, as a whole, is made up of a more or less homogeneous, but somewhat fissured, matrix that in nature is brown in color. The dark band running across the center represents partly charred wood, or fusaine often inaccurately described as 'mother of coaF or 'mineral charcoal." An examination of a wide range of coals shows that a great part of the brown matrix, which constitutes the mass of glistening coals with prismatic fracture, namely, bituminous coals and anthracites, is of woody origin; it is possible to trace in certain coals every gradation from wood with its structure perfectly preserved to that in which all trace of structural organization has disappeared. This possibility is presented in the case of fragments of wood or whole trunks or branches that have been partly charred by fire previous to inclusion in the raw material of the coal. The degree of charring marks the extent to which the original structure will be maintained in the fully matured coal, while complete absence of the action of heat creates a situation that often leads to the entire obliteration of structure in the course of ages. Between these two extremes lie imperceptible gradation, depending on the degree of exposure to heat. Illustrations of these modifications are shown in Figs. 3 to 5.

It follows from the statements regarding the woody origin of brownhued materials in thin sections of coal, that the coking coal from the Connellsville basin referred to consists mainly of woody materials, or rather of materials of woody origin. The valuable coking and steam coal, commercially known as Pocahontas coal, shows an organization very similar to that presented by Connellsville coal. It follows naturally that if the theoretical views just expressed concerning the origin of Connellsville coking coal are correct, they apply equally to Pocahontas coal.

Without exception, typical oil-shale and cannel coals are entirely refractory in the coking oven and do not give utilizable coke. In the case of oil shales, this condition is apparently absolute; in the case of cannel coals, which often exhibit considerable brown matrix in addition to the yellow spores, at best a light almost flocculent coke is produced. This is of slight value for household purposes and is not to be considered at all for utilization in the blast furnace.

Impressed by the organization of such highly valued coking coals as those from the Connellsville and Pocahontas areas, it has seemed to the author that the worth of the coal, from the standpoint of the coking industry, was in direct proportion, other things being equal, to its content of modified wood (Lignitoid, Jeffrey; Anthraxylon, Thiessen). An attempt was made to verify this hypothesis experimentally. Cretaceous lignites representing the trunks of trees, the affinities of which have been accurately

Coal In Relation To Coke

determined by the microscope, were subjected to strong heat in a closed crucible. In a number of instances these woody trunks, which have been much modified during long ages by the action of water, pressure, etc..

Fig. 9. — Vertical section through bituminous part of coal shown in Fig. 8;

This Coal Consists Mainly Of Structureless Wood And Of Spores.

Fig. 10. — Vertical section op bituminous coal prom Lancashire, England,

SHOWING large QUANTITIES OP SPORES AS WELL AS MODIFIED WOOD.

gave rise to quite typical coke. Fig. 11 shows the formation of the coke resulting from the heating of one of these woods in a confined space.

Edward C. Jeffrey

Obviously, the organization has largely disappeared as the result of the liquefaction following exposure to high temperature. The author has carried on a number of experiments of this kind in the case of fossil woods

Fig. 11. — Gross appearance of Cretaceous tree trunk that has been transformed INTO COKE BY HEATING IN A CLOSED CRUCIBLE.

Fig. 12. — Vertical section of coking coal from Connellsville area; this

IS MOSTLY COMPOSED OP MODIFIED WOOD, NEAR THE CENTER IS A SMALL FRAGMENT OP CHARRED WOOD IN TRANSVERSE SECTION.

from different geological periods. In many cases, the result has been the formation of a quite typical coke, while in other instances no coke resulted. In the latter cases, a process of charring was obvious but there

Coal In Relation To Coke

was no liquefaction followed by the formation of coke. As the structural organization of all the materials used in the present connection was purely woody, it follows that, in some instances, the wood had not undergone the chemical changes necessary to yield coke after being heated. It seems clear from the experiments described here and the illustrations that woody organization is a fundamental feature of the coals that can be transformed into coke in the oven; it follows, therefore, that not only must wood be the predominant constituent of the original raw materials of the coking coals, but it must have attained an appropriate degree of chemical modification. It is entirely likely that where time and nature have not brought the woody raw materials of the coals into a condition fit for coking, the knowledge and ingenuity of man can take the place of the slow processes of nature. It seems entirely probable, accordingly, that in the process of time, and as a result of our increase of knowledge of the chemistry of coal, all combustible minerals of mainly woody origin can ultimately be transformed into utilizable coke.

The author has one interesting example of a natural coke derived from a recent coniferous wood, which affords confirmation of his hypothesis that coking coals are formed of what was originally woody material. The specimen, dug up under a shallow covering of sand on Cape Cod, was sent to Prof. J. B. Woodworth with an inquiry as to its nature. He submitted it to the author, who discovered it to be a fragment of recent lignite, in a fair state of preservation, that had been partly transformed into coke.

If the views set down here are correct, coke has the same botanical origin as the charcoal it long ago replaced in the metallurgical industries. It follows, of course, that the original wood must have undergone the requisite chemical modifications in order to produce the substance known as coke. It is further clear that the presence of spore material, in any considerable amount in coking coals, is disadvantageous and that a large amount of spores effectually nullify the value of the coke that can be produced from any coal. A similar statement holds for those problematic organisms, which have been interpreted b3 some of my colleagues, as the remains of algae. The' not only present all the optical characteristics of spores but are likewise disadvantageous as a constituent of coal for coking piu-poses. Pure spore coals, whether they be regarded as such or considered to be of algal origin, are quite incapable of undergoing the process of liquefaction under high temperatures to which the name coking is given.

Discussion

David White,* Washington, D. C- — few of the slides look as though they had been treated by chemicals, either acids or oxides, before or after grinding. What is the maximum temperature developed in these

Senior Geologist, U. S. Geological Survey.

Discussion

slides ill the course of Uieir preparation? Most of the sections shown represent genuinely aquatic deposits laid down in ponds and lakes rather than normal coals. Some of the slides first exhibited are essentially what was described by Potoni6 as sapropel. In the small lake or pond, which may be 50 feet deep and which in any event is too deep for the growth of subaerial vegetation in place, the deposit will contain much sapropelic material. The shorter the radius of the water-body, the nearer the shore to all parts of the area of accumulation, and the greater the opportunity for infall or drift of carbohydrate land vegetation into the aqueous deposit. Therefore, small sapropelic deposits like the typical cannel coals, which are laid down in ponds or little lakes, or in the sluggish cut-off bayous in the swamp, may contain considerable drifted wood or other detritus, as well as windblown spores, drifted pollen, and other small resistant debris.

The greater the extent of the water-body the less the amount of contributed debris of land origin and the greater the proportion of distinctly aquatic life. The canneloid type, which is shown in about half of Doctor Jeffrey's slides, is distinctly an aquatic deposit of the former (small lake or bayou) type and is not typical of our coals, which are generally xyloid. One does not think of a forest bordering the bayou or lake without shedding its pollen or dropping its leaves and twigs where they may blow or drift into the pond. The spores shed from the ferns are transported for long distances in the air and, together with the pollen grains, are characteristic if not dominant in the open-water deposits of the canneloid type. Again, the larger this body, the smaller in general will be the proportions of land derived spores or of pollen.

If the conditions of deposition are such as to permit oxidation and so to interfere with the concentration of ulmic matter to the point of toxicity to the germs, the woody material will continue to decay, for the most part, at least, as is usually found to have been the case in the canneloid deposits. Even in the terrestrial swamps aeration or slowness of accumulation of plant detritus may permit the loss of nearly all the woody material, leaving only the most resistant plant elements, such as spore and pollen exiles, resins, and fragments of cuticles to survive in the deposit. Accordingly, we have, in passing from layer to layer in most coal beds, great variation in the amount of spore and other ultra-resistant debris, while in other layers greater toxicity of the aqueous medium has caused the conservation of more of the wood and other less resistant plant structures. In most deposits great amounts of plant matter are sacrificed before effective toxicity is reached through the accumulation of the ulmic products of smothered decomposition.

Cannels intergrade through the larger lake deposits into oil shales and bituminous shales in general.

Coal In Relation To Coke

Striped or banded' coals are quite normal, in fact they are most common. The amount of wood in the ordinary coal may be from 15 to 85 per cent, or more, according to the condition of deposition. If the preservation of the wood is good, the wood is much more in obvious.

I am a little uncertain as to whether the author concludes that all the mineral charcoal scattered here and there in his peat deposits or pond deposits, become charcoal after burial of the deposits, or whether it came into the deposit as charcoal.

E. S. SiNKiNSON, Bethlehem, Pa. — What is it in coal that goes to form coke? Can it be the gases produced by a thermal decomposition of coal decomposing to give a nucleus of carbon in so fine a state of division that forces of cohesion come into play which bind them into the foundational structure of a coke?

S. W. Parr,* Urbana, 111. — Are these zones where charring has taken place burning in the ordinary sense, or after being closed and subjected to geological conditions?

James F. KEMP,t New York, N. Y. — Several times, in the past twentyfive years, when there have been severe forest fires in the Adirondacks charred leaves have come floating down out of the atmosphere and gently deposited on the surface of Lake George. All the discussion has assumed that the charred material would be deposited in a coal seam through the urgency of water, but the rush of hot air in a forest fire carries charred leaves up into the air and they are transported miles before they come down. Many times the fires were so far away we had no information as to the location; they were perhaps 25 miles away from the lake.

I could not help but be impressed with the discussion that the increased combinations of coals, as against the vegetable materials, is largely a matter of oxidization, whatever process we describe, whether the fraction or influence of bacteria make progressive anastomozing from vegetable matter to peat, so on to bituminous and anthracite, but with a progressive relative increase in the carbon. Just where we would draw the line in these processes between the oxidization and combustion, might be a difficult matter.

David White. — We are quite generally in agreement that ordinary coking coal represents the woody type of coal, whether lignite, subbituminous or semi-bituminous, which has been brought to the coking stage in the course of its evolution, — called carbonization or devolatilization. The coking qualities are generally excellent when the fixed carbon (pure coal basis) of these woody coals approximates 65 to 75 or is even as

Professor of Applied Chemistry, University of Illinois, t Professor of Geology, Columbia University.

Discussion 161

high as 83 per cent. "Mineral-charcoal" (fusain) is generally abundant in coking coals.

Edward C. Jeffrey. — As regards the nature of coking, I, may say that wood of the same geological age, undoubtedly pure wood (I mean pure as regards structure) that has undergone the lignitic modification, can be coked in an ordinary closed retort; others cannot. That is the result of a degree of chemical modification that the original wood has undergone. I understand that it has been found possible to transform the ordinary wood into a substance like coal by heating it in vacuum for a prolonged period.

The microscopic study of this coke — and I have been able to get every stage of the modification from the original lignitic material to coke — shows that it is not any resinous material which is responsible for the coking unless that resinous material is secondarily derived from modification of the walls of the elements of the wood. In the preparations, you can see the walls melt and run together with the development of a moderate amount of gas, which is responsible for the porousness of coke. The piece of natural coke from Cape Cod was dug up under several feet of sand; it was not in the water at all. It may have been in the water at some time, but not in recent times at any rate.

I said at the outset that I was not dealing with chemical matters at all; all I claim is the structure of the coal is not modified. I have studied ground sections and sections of coal side by side, and where there is no difference between structure. I have found in sections very minute and delicate structures, and I am afraid the work will outlast my power. In the case of Mesozoic substances, the charred material can get in the water and come to rest without injury, even when it is of very delicate origin.

Reinhardt Thiessen,* Pittsburgh, Pa. — I have found invariably with ordinary bituminous coals, even those coals called non-coking, that that part of the coal derived from the woody parts of plants, which I call anthraxylon, cokes: the attritus in the same coal does not coke. In the typical coking coals, the resinous and the spore matters have largely disappeared and the woody derivatives have remained. For example, in tracing the Pittsburgh from its extreme western limits to the east, the coking properties of that coal increase. As the region of the typical coking coals is approached, the spore-matter disappears until, as at Connellsville, it has disappeared altogether. Why those spores should have disappeared I do not know. That the coal once did contain spores is shown by the cavities in which they were once located. The resinous matters have been charred or devolatilized so that they are opaque. It seems then that the woody parts of the plants have furnished

VOL. LXXl. 11

Research Chemist, Bureau of Mines.

Coal In Relation To Coke

the coking constituents of coal. But in order to be coking, favorable factors must coincide.

Chas. R. Fettke,* Pittsburgh, Pa. (written discussion). — Several years ago, while engaged in an investigation of the oil resources in coals and carbonaceous shales of Pennsylvania for the Pennsylvania Geological Survey, the writer made a series of low-temperature carbonization tests on samples from all the known cannel coal deposits in the state. Since that time tests have also been made on oil shales from numerous other localities, including samples from different beds in the Green River formation of Colorado and Utah. While in most instances, the cannel coals and oil shales show little or no tendency to coke, there are some notable exceptions.

Among samples of cannel coal and shale representing thirty-one localities in Pennsylvania, three were found that possess the coking property to a rather marked degree. As a rule, cannel coals have a higher ash content than ordinary coals; this is particularly true of the Pennsylvania occurrences. The deposits that have been mined on a small scale in the state in recent years contain from 11 to 27 per cent, of ash; only four samples were obtained that contained less than 20 per cent. It seems likely, therefore, that in some instances at least the high ash content has affected the coking properties.

The purer portions of the famous Cannelton bed of cannel coal in the northwestern corner of Beaver County, Pa., form a hard dense coke. Pores, while numerous, are not as large as those ordinarily developed in coke from bituminous coking coals. Occasional fragments of unfused material, undoubtedly representing bony streaks in the cannel coal, are embedded in it. These are no more numerous, however, than in the cokes derived from many ordinary bituminous coals. The cannel coal on heating fuses and, at first, swells somewhat but later shrinks in volume so that the resulting coke does not occupy the entire space of the original charge.

Fig. 13 shows the coke obtained in testing a sample, taken from near the center of the channel-like deposit, in a Bureau of Mines oil-shale assay retort. The coal was crushed to pass a 4-mesh screen. It yielded at the rate of 49 gal. of oil per ton and had the following composition: Moisture, 1.26 per cent.; volatile tnatter, 44.49 per cent.; fixed carbon, 34.28 per cent.; ash, 19.97 per cent. A sample from near the edge of the deposit, which contained 27.48 per cent, ash, showed only a slight tendency to coke. Inasmuch as the spent material from this sample contained 44.2 per cent, ash, the difference in behavior can be readily accounted for.

Associate Professor of Geology and Mineralogy, Carnegie Institute of Technology.

Discussion

Ioctor Thiesseu has made studies of the samples tested and has found that the Cannelton deposit, which occurs at the Upper Kittanning horizon, represents a typical spore cannel coal. Photomicrographs of this coal are shown in previous publications by the writer. Another cannel coal that forms a hard dense coke was obtained from what is also probably the Upper Kittanning horizon in the country bank of G. W. Currie, 2 miles north of Nealeys, Butler County, Pa. It yields

Fig. 13. — Coke from Cannelton, Pa., canjtbl coal.

at the rate of 33 gal. of oil per ton and has the following composition: Moisture, 0.83 per cent., volatile matter, 38.94 per cent.; fixed carbon, 49.14 per cent.; ash, 11.09 per cent. Doctor Thiessen classifies it as a humic type of cannel coal. Photomicrographs are shown in the publications just referred to (PL IV, Fig. A; and Fig. 2, page 1169, respectively).

The third sample of cannel coal that forms a hard porous coke came from a deposit at the Upper Kittanning horizon near the head of Crooked Run, 3 miles south of Savan in Indiana Coimty, Pa. It yields at the rate

1 Oil Resources in Coals and Carbonaceous Shales of Pennsylvania. Pennsylvania Geol. Surv. (1923) PL II, Fig. C; Cannel Coal and Carbonaceous Shale Deposits of Pennsylvania. Trans. (1923) 69 , 1169, Fig. 1.

Coal In Belation To Coke

of 19 gal. of oil per ton and has the following composition : Moisture, 0.53 per cent.; volatile matter, 27.64 per cent.; fixed carbon, 53.98 per cent.; ash, 17.85 per cent. The low percentage of volatile matter is undoubtedly due, in large part, to the fact that the deposit occurs in an area in which the coals have been subjected to a greater degree of metamorphism. While the bituminous coals of Beaver and Butler counties contain from 55 to 63 per cent, of fixed carbon, computed on a pure coal basis, those of Indiana County contain from 63 to 79 per cent. Unfortunately, no microscopic studies have been made of specimens from this locality.

Dunlap,® in carrying out carbonization tests on Missouri cannel coals has also found a wide range in their coking properties; out of four samples tested, only two gave coke of commercial value. According to this investigator, the Bunceton cannel coal from Cooper County, Mo., yields a very good coke. It is hard and the entire charge fuses together; the porosity is about the same as that of ordinary coke. The Stover cannel coal, from Morgan County, Mo., also yields a good coke, but it is high in sulfur. The Bunceton coal contains 8.16 per cent, ash and yields at the rate of 53.5 gal. of oil per ton; while the Stover coal contains only 2.3 per cent, of ash and yields at the rate of 64.88 gal. of oil per ton. Microscopic studies of these coals to determine the type of cannel coal represented would be desirable.

Some of the richer oil shales from the Green River formation of Colorado, examined by the writer, show a decided tendency to fuse when heated. The crushed shale, when carbonized in a closed retort, fuses completely and shrinks markedly in volume. The resultant mass clings tenaciously to the walls of the retort and is difficult to remove. This property will have to be taken into consideration in designing retorts to treat this particular type of shale. Other oil shales in the same formation, equally rich as far as yield of oil is concerned, show practically no tendency to fuse. Finley, Home, Gould, and Bauer® have also called attention to this tendency of certain oil shales to coke. Of course, the term coking as applied to oil shales does not mean that a metallurgical coke is produced. There is, however, a certain resemblance in behavior between these oil shales and ordinary bituminous coking coals when they are undergoing carbonization.

'Howard Leroy Dunlap: The Carbonization of Missouri Cannel Coals. Bull. Missouri School of Mines (1919) 6 , No. 1, 49. -

W. L. Finley, J. W. Horne, D. W. Gould, and A. D. Bauer: Assay Retort Studies of Ten Typical Oil-Shales. Reports of Investigations, Bureau of Mines, Ser. No. 2603 (1924) 6.

Resolution Op Coal By Oxidation

Resolution of Coal by Oxidation

By W. Francis* and R. V. Wheeler,! Sheffield, Engllnd

(New York Meeting, February, 1925)

Of the methods that have been used for studying the chemical composition of coal, attack by reagents has not, in general, yielded much information. Most of the reagents used have been strong oxidants such as nitric acid or Schulzes solution. The use of a milder oxidizing agent, such as air at low temperatures, enables progressive changes in the character of the coal substance to be studied and thus helps toward an understanding of its constitution.

British bituminous coals frequently have a banded structure. These bands (of four types) can be separated one from another and have been found to possess markedly different chemical characteristics, even when taken from contiguous portions of the same lump coal. It has been found convenient to give each of the ingredients of banded coal a distinctive name, more or less descriptive of its appearance, and the study of the chemistry of bituminous 'coaP in England has resolved itself into a study of each ingredient separately.

The coal chosen for this work was taken from the Top Hard seam at East Kirkby colliery, Nottinghamshire, a detailed chemical analysis of which has been recorded by Baranov and Francis. The banded structure was well marked and the bands could readily be separated. The research was confined to the brilliant vitreous bands {vitrain), the dull hard bands (drain) and the 'sooty partings' (Jusain); for previous work had shown that the fourth type, to which the name drain has been given, is intermediate in character, chemically, between vitrain and drain.

The method of experiment was, briefly, to draw a slow current of moist air through weighed samples (50 gm.) of the three ingredients, vitrain, drain, and fusain, in the form of powder (through a 60-mesh and on a 90-mesh sieve) contained in glass tubes which could be maintained at a constant temperature during prolonged periods. After passing through the coal, the air bubbled into a measured volume of

Junior Assistant, Safety in Mines Research Board.

t Professor of Fuel Technology, Sheffield University; Director of Research, Safety in Mines Research Board.

Fud in Sci, (fc prac, (1922) 1, 219.

Resolution Of Coal By Oxidation

cold distilled water to condense or dissolve any gaseous products of the oxidation. At stated intervals (usually 1 month) for each temperature employed, this water was examined and changed and a small fraction (5 gm.) of each coal was removed from the tubes for analysis. The temperatures used in the oxidation were 100® C., 150° C., and 200° C., and the total time allowed for oxidation at each temperature was 5 months, 6 months, and 6 weeks respectively.

Liquid and Gaseous Products

The chief products identified were formaldehyde, methyl alcohol, and the lower fatty acids. During oxidation at 100° C., these were obtained in small quantities from all three ingredients; but at higher temperatures, the vitrain and drain produced only traces of formaldehyde and acids and the fusain none at all.

Changes in Composition

Table 1 shows the progressive changes in weight as the oxidation proceeded. A loss in weight, which was most marked during the oxidations at 200° C., caused a corresponding increase in ash content.

Table 1. — Changes in Weight as Result of Oxidation

Change in Weight

Ash Content

Fusain, Durain, Vitrain, Fusain, i Durain, Vitrain,

' Per Cent. Per Cent. Per Cent. ! Per Cent. ' Per Cent. ! Per Cent.

i ' I ,

Original

!

- - —

lOO'C. I

-h 1.74

+ 0.1

nil

150° C. I

! 17.90

- 3,0

200° C. I

!

Proximate Analysis

The volatile matter (see Table 2) calculated on an ash-free, dry basis, showed but small fluctuations during oxidation at 100° C., the net result being a slight gain with the fusain, a slight loss with the drain, and little change with the vitrain. On oxidation at 150° C., however, all showed a greatly increased content of volatile matter. This was greatest with the vitrain and the change was completed during the first period of

W. Fbanci8 And B. V. Wheeleb

heating (2 months). With the drain and the fusain, the volatile matter increased more gradually and the change may not have been completed during the 6 months the experiment lasted. On oxidation at 200® C., the volatile matter of the vitrain showed a decrease. This fact, together with other observations discussed later, suggests that decomposition of the oxidized product had begun. Both the drain and fusain showed a slight increase in content of volatile matter.

Table 2. — Proximate AnalysiSy Percentages on Ash-free Dry Coal

' Volatile Matter, Ash-free Dry Coal

Ulmins

Fusain,

Per Cent.

Durain, ' Per Cent.

Vitrain, Per Cent.

Fusain, Per Cent

Durain,

Per Cent.

Vitrain, Per Cent.

Original

nil

100° c.

, 26.55

150° C.

32.1 !

200° C.

These results can be explained by the determinations of the amount of ulmins (compounds soluble in caustic alkalies) present. After oxidation at 150° C., the coals contained large quantities of ulmins and their properties then became largely those of the ulmins they contained. The volatile matter of the ulmins is high (about 41 per cent.) and the volatile matter of the coals oxidized at 150® C. approached this figure as their ulmin contents approached 100 per cent.; while during oxidation at 200® C. there is evidence of decomposition. The coking properties of the vitrain were completely destroyed after 2 months oxidation at 100® C. Neither the drain nor the fusain formed a coherent coke either before or after oxidation.

Table 3 shows the effect of oxidation on the behavior of solvents toward the coal. The nomenclature proposed by Stopes and Wheeler has been used, in which the terms alpha, beta and gamma compounds are used, respectively, for the portions of coal insoluble in pyridine, soluble in pyridine but insoluble in chloroform, and soluble in both pyridine and chloroform. It should be noted, however, that the character of these fractions is not necessarily the same for both the unoxidized and the oxidized coals.

Resolution Op Coal By Oxidation

Table 3. — Solubility in Pyridine and Chloroform

Fusain

Durain

Vitrain

Per

Cent.

Beta,

Per

Cent.

Gamma,

Per

Cent.

Per

Cent.

Beta,

Per

Cent.

Gamma,

Per

Cent.

Per

Cent.

Beta,

Per

Cent.

Gamma,

Per

Cent.

Original

100® C. I

?

, Iii

150® C. I

Trace

, 0.5

Trace

19,7

Trace

! 20

nil

' 77.0

ml

nil

200® C. I .

, 11

1 ml

j 78.0

ml

nil

' 13

! nil

nil

30

nil

As with the contents of volatile matter, the differences due to oxidation at 100° C. were small. A fact that the figures do not show is that the beta compounds of the oxidized coal were largely ulminified. There was a tendency for the gamma compounds of the vitrain to lose their solubility in chloroform on oxidation even at 100° C., while after oxidation at 150° C. this solvent extracted very little, if anything. Similarly, with the drain and the fusain, no gamma compounds were present after oxidation at 150° C.

With all the coals, there was a marked increase in solubility in pyridine, up to a maximum of 45 per cent, observed with the vitrain (coincident with the maximum formation of ulmins).

Ultimate Analysis

The vitrain, drain, and fusain from the original Top Hard coal showed the same gradations in ultimate analysis as were found by Tides-

Table 4. — Ultimate Analyses, Percentages on Ash-free Dry Coal

Fusain

Durain

Vitrain

Carbon,

Per

Cent.

Hydro-

Cent.

Oxygen,

etc.,

Per

Cent.

Carbon,

Per

Cent.

Hydro-

gen,

Per

Cent.

Oxygen,

etc..

Per

Cent.

Carbon,

Per

Cent.

Hydro-

gen,

Per

Cent.

Oxygen,

etc.,

Per

Cent.

Original

100®C I...

150® C. I. ..

Ii ,

200® C. I...

W. Francis And R. V. Wheeler

well and Wheeler® for Hamstead coal. During oxidation of the Top Hard coal, there was a progressive loss of carbon and hydrogen and an increase of oxygen. The amount of oxygen reached a maximum with the vitrain at 150° C., when the coal substance had been completely converted into ulmins. When decomposition of the ulmins by heat began (at 200° C.), the oxygen content was slightly decreased owing to the elimination of carbon dioxide. Analyses of the drain and fusain gradually approached that of the vitrain but never quite reached it, because of the presence of some portions of the coal conglomerate that were difficult or impossible to oxidize.

The analyses of the ulmins produced from all portions of this seam of coal were similar. This fact, together with the similarity of the analyses of the gases produced on their destructive distillation (see later), indicates that the ulmins produced by oxidation of all parts of the same seam of coal have the same composition. The analyses of these ulmins averaged: Carbon, 64.5 per cent.; hydrogen, 2.8 per cent.; oxygen, etc., 32.7 per cent, and they contained 41.5 per cent, of volatile matter. They were completely soluble in ammonia and in solutions of potassium and sodium hydroxide, and potassium and sodium carbonate; while pyridine dissolved about 51 per cent. They were insoluble in chloroform.

Table 5. — Percentages of Nitrogen and Sulfur

Fusain.

[ 1

j Durain, . Vitrain,

Per Cent.

Per Cent, j Per Cent.

Nitrogen:

Before oxidation

After oxidation

Sulfur:

Before oxidation

After oxidation

!

Sulfate Sulfur:

!

Before oxidation

nil

After oxidation

j i

In the figures for the percentages of oxygen, the nitrogen and sulfur present in the coals are included. During the oxidations no nitrogen was lost, but the nitrogen-containing nucleus survived and appeared in the ulmins. The percentage of nitrogen in the oxidized coals was increased proportionally with their loss in weight. The sulfur in the original coal existed partly in inorganic form. During oxidation, a portion of this was evolved as sulfur dioxide and a portion changed from sulfide to sulfate. As a portion of the sulfur (organic) remained in the ulmins produced, it may be concluded that sulfur is also a con-

Trans, Chem. Soc. (1919) 116, 619.

Besolution Op Coal By Oxidation

stituent of this nucleus, though the quantity present is less than that of the nitrogen; see Table 5.

Oxidation by Hydrogen Peroxide

Ulmins may be produced from coal more quickly by chemical oxidizing agents than by atmospheric oxidation. The simplest and quickest oxidizing agent was found to be a solution of hydrogen peroxide. This has been used with a number of coals, usually in alkaline solution so as to obtain the ulmins in solution. Anthracites are not appreciably oxidized by hydrogen peroxide but lower grade coals soon become soluble in alkalies and the soluble portions continue to be oxidized until a limiting composition is reached agreeing closely with that of the ulmins formed on atmospheric oxidation. The upper limit of composition for ulmin compounds soluble in alkalies has been found to be about 70 per cent, carbon and 4.2 per cent, hydrogen and the lower limit about 62 per cent, carbon and 2.8 per cent, hydrogen. Below this limit of composition, the sodium salt of the ulmins could not be oxidized but the free acid was readily decomposed apd during the decomposition the nitrogen contained in the compounds was evolved quantitatively as ammonia.

Destructive Distillation

An examination of the gaseous products of destructive distillation confirmed the resemblance between the ulmins produced from the vitrain and drain of the same coal. With both, decomposition began at as low a temperature as 150° C. and the gases evolved consisted entirely of oxides of carbon in the ratio CO>:CO of about 12:1. This ratio decreased as the temperature of decomposition was increased. No other gaseous products of importance were evolved below 450° C. when methane and hydrogen made their appearance. The chief results are recorded in Tables 6 and 7 and in Figs. 1 and 2.

A comparison of these results with those for unoxidized vitrain on the one hand and dopplerite on the other reveals that the groupings in these two substances, from which unsaturated hydrocarbons (and some methane and hydrogen) are evolved, are absent in the ulmins from oxidized coal, which suggests that oxidation had caused a progressive splitting off of external groupings leaving a nucleus. This nucleus appears to be of the same character in dopplerite, vitrain, and the amorphous portions of drain, clarain, and fusain, and the first stage in the progressive oxidation of coal is a change from insoluble into soluble ulmins by a modification of the external groupings.

Oxidation of the nucleus, which contains both nitrogen and sulfur, is both rapid and complete when hydrogen peroxide is used, and the only

Trans, Chem. Soc. (1922) 121 , 2345.

W. Francis And R. V. Wheeler

Table 6. — Principal Gases Evolved on Destructive Distillation; Cubic Centimeters per Gram of Ash-free Dry Substance

Vitrain Ulmin

Temperature, Degrees C.

Carbon dioxide !

Carbon monoxide

Hydrogen

nil

Methane

nil

2.84 '

Ratio CO

Analysis carbonized residue: Carbon, 80.6 per cent.; hydrogen, 3.4 per cent.; oxygen, etc., 16.0 per cent.

Table 7. — Principal Gases Evolved on Destructive Distillation; Cubic Centimeters per Gram of Ash-free Dry Substance

Durain Ulmin

Temperature, Degrees C. , 170

Carbon dioxide 7.82

Carbon monoxide ... 0.58

Hydrogen nil

Methane nil

Ratio 13.24

nil

ml

nil

ml

nil

ml

nil

ml

O.Os

nil

Analysis of carbonized residue: Carbon, 83.3 per cent.; hydrogen, 3.2 per cent.; oxygen, etc., 16.0 per cent.

Resolution Of Coal By Oxidation

products SO far isolated are monobasic and dibasic fatty acidS; oxides of carboD; ammonia, and water. It is hoped, in future work, suitably to moderate oxidation of the nucleus so as to be able to isolate intermediate compounds.

Presence of Plant Debris

The treatment of coal with hydrogen peroxide has made possible a close study of those parts that do not become transformed into soluble ulmins. Microscopical examination has revealed that the residue consists of plant debris. In the residue from a fusain, wood tracheids have

Fig. 3. — Wood tracheid from fusain. Fig. 4. — Parenchymatous tissue from X 140. DURAIN. X 140.

always predominated (Fig. 3). The debris from the clarains and drains examined have differed but little from one another in general character. They are transparent and show a variety of recognizable structures, varying in color from deep red to pale amber, while some fragments are green as though the chlorophyl has been preserved. Spore exiles and portions of epidermis are of frequent occurrence and fragments of soft-walled tissue are sometimes to be found. The surface views of the parenchymatous tissue isolated exhibit polygonal cell outlines, showing that the fragments are of epidermis of leaves or young stems. Many fragments of such tissues show the stomata in surface view (see Figs. 4, 5, 6, and 7) and are colored pale yellow and brown. Some thickened tissues are also present, of deep mahogany color, presumably the remains of the periderm. Microspore exiles are numerous and their size and ornamentation varies considerably. The characteristic triradiate marking is often observable while a few of the spore exiles have well developed

W. Francis And R. V. Wheeler 173

''wings characteristic of the microspores of Spencerites. The megaspore exiles are usually broken into small fragments, because of the grinding

Fig, 5. — Same specimen as in Fig. 4. Fig. 6. — Parenchymatous tissue from X 280. drain. X 140,

the coals receive before their treatment with hydrogen peroxide but a few complete exiles have been separated. These are almost spherical

Fig. 7, — Same specimen as in Fig, 6, Fig. [8. — Spore exine from drain. X 280. X 30.

bodies, dark brown in color, exhibiting triradiate marking and sometimes having hairs attached, as in some species of Lejndostrdbus (Fig. 8),

Resolution Of Coal By Oxidation

In one coal examined (the Hamstead), the debris obtained after treatment with hydrogen peroxide contained minute amber-colored rods apparently containing no cell structure. Some of this debris was extracted with chloroform, which yielded a semi-solid brown mass having an analysis: carbon 80.3 per cent, and hydrogen 10.4 per cent. The rods thus appear to be resin and to be analogous to the resin rods observed by White in American coals.

Summary

The present work shows that alkali-soluble ulmins can be regenerated from a bituminous coal by mild oxidation. If the coal is a vitrain, it consists almost solely of ulmins; the transformation of insoluble to soluble ulmins in a clarain, a drain, or a fusain leaves residues characteristic of each of these ingredients, which are essentially the original plant entities that were particularly resistant to, or were preserved from, the process of decay'' that constituted the early stages of coal formation, and are, apparently, but little altered.

Bituminous coal, then, consists of insoluble ulmins in which are dispersed the morphologically organized plant tissues that have escaped ulmification.

Discussion

Edward C. Jeffrey,* Cambridge, Mass. — Two or three years ago the president of the Chemical Society said that it was possible to treat almost any bituminous coal in such a way that it would coke; can anybody throw some light on that statement?

S. W. PARR,t Urbana, 111. — On the border line, perhaps, are the Illinois coals, which are non-coking. I am quite sure they can be made to coke.

E. S. SiNKiNSON, Bethlehem, Pa. — Do the terms "drain," "clarain," and "vitrain" give any clearer understanding of the subdivisions of coal than do dull, bright, or glance? Are the captions of Figs. 4, 5, and 6 correct? They look like epidermis. In discussions on the composition of coal why are the nitrogenous contents so much neglected, when they are relatively so important?

Reinhardt Thiessen,J Pittsburgh, Pa. — Nitrogen in the coal is considered in my paper. Proteins are easily decomposed and their nitrogen is changed to ammonia, which escapes; but in the compounds I mentioned, the nitrogen forms part of a ring that is not broken up during decay.

Professor of Botany, Harvard University, t Professor of Applied Chemistry, University of Illinois,

J Research Chemist, Bureau of Mines,

Discussion

David White,* Washington, D. C. — A point in this paper that is specially interesting to me is the observation of the progressive increase in capacity for regeneration according to the amount of woody material in the coal, the reaction of the fusain ("'mineral charcoal") being least, that of drain being intermediate, while in the bright stripes largely composed of ulmified wood it is very much greater. The ulmic matter, which forms the groundmass of the coal and is present in all coals, and is largely derived from carbohydrate or lignocellulosic material, is relatively more abundant in drain than in fusain, and is perhaps most abundant — at least in effect — in the so-called vitrain. In the woody material — assuming vitrain is woody, though it is so glassy, so completely impregnated, so homogeneously ulmified, as to be reluctant to reveal its woody structure — we have not only the carbohydrate derivative of the binder, but the carbohydrate derivative or transformed carbohydrates of the undecomposed woods. The latter have, of course, long since been chemically transformed beyond the cellulose or other carbohydrates as we now recognize them. It would appear either that the ulmic matter which so copiously impregnates and envelopes the woody tissue is more easily oxidized, or that the transformed carbohydrates of the wood itself so approach in chemical composition the ulmic matter as to play a similar role in the oxidizing process. On the whole, may we not infer that the capacity of these coals to oxidize, with the regeneration of ulmic matter, varies with the amount of ulmified wood as well as of ulmic binder in the coals of a given rank?

Edward S. Jeffrey. — Some years ago, a memoir on lignites was published from my laboratory, where the nuclei were shown. The situation would compare somewhat with Doctor Thiessens remark in regard to the Connellsville coal; the spores were there.

Senior Geologist, U. S. Geological Survey.

The Constitution Op Coal

The Constitution of Coal

By F. V. Tideswell* and R. V. Wheeler f Sheffield, England

(New York Meeting, February, 1925)

Coal being essentially a complex conglomerate of plant remains that have undergone decay and interaction in varying degree, it is understandable that attack on the problem of its chemical constitution by normal chemical methods should have been attended by but slight success. The obvious method of fractionation by means of selective solvents has yielded a few results of some value. Thus it is known that from many, if not all, bituminous coals organic solvents extract small percentages of oxygenated compounds, which are generally assumed to have been derived from the original plant resins, though a more probable source would appear to be the glycerides and waxes of the plants. Organic solvents also extract small proportions of hydrocarbons, the origin of which is doubtful. Of more importance is the action of such pseudo solvents as pyridine, which, in addition to their specific solvent action, have the power of resolving and simplifying a portion of the coal substance in a manner analogous to that by which water can disperse a hydrogel. Early work with pyridine indicated that coals are composed of two main classes of compounds: the one soluble in organic solvents, the other capable of being partly dispersed in pyridine. Recent work has shown that the dispersion is colloidal in character and that it may be accomplished by the use of solvents less active than pyridine, such as benzene or chloroform, provided that the temperature of extraction is raised or the coal has been suitably preheated.

The action of reagents on coal has proved of little value in the past, but some insight into the constitution of coal has been given by regulated destructive distillation. Thus, it has been shown that coals behave on distillation as though composed of two main classes of compounds: the one readily decomposable at moderate temperatures (yielding mainly the paraflins), the other undergoing a preliminary early decomposition (with evolution of oxides of carbon and water) and yielding a residue that at higher temperatures breaks down, yielding much hydrogen.

Senior Assistant, Safety in Mines Research Board.

t Professor of Fuel Technology, Sheffield University, and Director of Research, Safety in Mines Research Board.

F. V, Tideswell And R. V. Wheeler

In view of the diversity of materials that enter into the composition of the coal conglomerate, success in determining the constitution of coal cannot be expected unless the character of each type of material is considered alone and until the extent of the contribution of each to the coal substance is known. A comprehensive scheme of coal research should, therefore, comprise a study of each individual plant entity or degradation product thereof that occurs in coal. This, broadly, is the basis on which investigations into the constitution of coal are proceeding in England under the Safety in Mines Research Board and in the Department of Fuel Technology of Sheffield University. Different programs of research deal with the contributions to coal of cellular tissue, of imorganized or amorphous material, such as the ulmins and the resins, and of structured materials such as cuticles and spore exiles. Usually a preliminary inquiry into the chemistry of corresponding modem substances has proved necessary. For example, an investigation into the character of a peat ulmin (dopplerite) has shown a marked relationship between this and an amorphous portion of banded bituminous coal. Work designed to extend our knowledge of the constitution of the modern ulmins is now proceeding, together with an investigation of synthetic ulmins from various sources.

The natural ulmins, the brown amorphous products of plant decay, first attracted the attention of chemists on their extraction from the rotted wood of an elm tree by alkaline solutions from which they were precipitated by acids as brown flocks. The solubility in alkalies and reprecipitation in an amorphous form on acidification were long used as the sole criteria of what constituted an ''ulmin, but there is now considerable evidence that similar substances, insoluble in alkaline solutions, can with advantage be referred to under the same general name.

Ulmins are found in any substance derived from vegetable matter that has undergone moldering decay; for instance in soils, peats, and to a less extent in lignites and coals. The ultimate composition of all such ulmins is similar, ranging from 50 to 60 per cent, carbon, 4.5 to 6.0 per cent, hydrogen, 0.5 to 2.0 per cent, nitrogen, and 30 to 40 per cent, oxygen. Substances of similar type, but of somewhat different composition, have been obtained by the action of reagents on vegetable matter and by the treatment of such materials as sugars and derivatives of furan and phenol with boiling dilute acids. Other artificial ulmins are produced by the oxidation of lignin in the presence of alkalies, and by the condensation of sugars (and carbohydrates in general) with simple or complex amino acids. These reactions are of interest mainly because they suggest the manner of formation of natural ulmins.

1 Thomson (1807) named them ulmins because of their original association with the elm (Latin ulmtis),

Vol. Lxxx. 12

The Constitution Of Coal

The exact constitution of the ulmins is, at present, unknown. They appear to possess an acidic character, but the source of the acid function, whether phenolic or carboxylic, is undecided. The natural ulmins appear to be related, in structure, to the lignin and cellulose of the cellular tissues of the plants from which they were formed, for alcoholic hydroxyl groups are present in large proportions, while methoxyl groups are also found. Fischer and Schrader consider the lignin alone to have provided ulmins when the plants decayed, while Marcusson thinks the cellulose was chiefly responsible. From our own examination of peat ulmins, we are disinclined to argue, with either Fischer and Schrader or Marcusson, their formation from one class of original plant substances to the exclusion of another class, or to argue the survival in them of the lignin complex to the exclusion of the cellulose, or vice versa. We have observed some evidence of a carboxylic acid function in peat ulmins, while the hydroxyl content appears to be almost 30 per cent, of the whole. Destructive distillation discloses resemblances with both lignin and cellulose, while the nitrogen present appears to be very firmly linked. We conclude that the peat ulmins, considered to have been derived from degraded cellulose, lignocellulose and proteins (condensed together with partial dehydration as with the amino-ulmins of Maillard) still preserve the original lignin and cellulose groupings, together with new ringed structures containing oxygen and nitrogen. The formation of ulmins in nature appears to have been due to chemical rather than bacterial action, and of the various suggested chemical reactions that between carbohydrates and amino-compounds (probably following their liberation by bacterial action) seems the most likely.

The extent of the contribution of the ulmins to coal has occasioned much debate. Without reverting to the extreme conception of the "fundamental jelly" of Fremy, we consider as the result of recent work that many, if not most, British coals consist largely of ulmic material. This view is not inconsistent with the presence of the wealth of plant materials that are visible in transparent sections of most coals. Despite their number, the contribution of these by weight is not necessarily large.

It is of interest to trace the changes that we may suppose have taken place during the aging of a deposit of plant remains. The original material may be compared with peats of various ages (as representing a conveniently studied form of partly degraded plant debris) and with coals. The various plant entities and residues that have contributed to the formation of the organic substance of coal can conveniently be grouped according as they are:

1. Resistant to decay: Among the more important members of this group are: (a) Spore exiles and cuticular tissues; and (6) resins.

Brennstoff Chem, ( 1921 ) 2, 23 .

Ztachr, f, angew, Chem. ( 1923 ) 36, 42 .

F. V. Tideswell And R. V. Wheeler

2. Subject to decay: The members of this group are either: (a) Organized, such as cellulosic and dignified tissues; or (6) amorphous, the contents of plant cells.

3. The products of decay: The ulmins.

An accumulation of plant remains immediately after deposition consists mainly of the first two groups, but in an older deposit, such as a peat bed, certain changes have taken place. The members of group 1 are still present in an apparently unaltered form. The cellulose and lignin of the group 2, however, have suffered decay, undergoing such minor alterations as dehydration produces, or becoming ulmified (probably in conjunction with certain of the cell contents), or disappearing altogether. According to Fischer and Schrader, the lignin alone survives in any form, the cellulose of necessity vanishing (being converted into liquid and gaseous products through the agency of bacteria), but we cannot regard this view as either proved or probable and consider that ulmins can be produced from any plant material of carbohydrate type. Judging from the nature of peat, ulmification is the main chemical process during the decay of plants and it proceeds further the older the deposit. Thus, while a young peat may yield only 10 or 20 per cent, of material soluble in alkalies, from an older peat as much as 70 or 80 per cent, can be extracted.

In a deposit of the age of coal, it cannot be expected that the materials of any of the three groups will remain unaltered. Spore exiles and cuticular tissues may not be much changed, nor need the resins, but the cellulose that is not totally destroyed will in large part be converted, together with the more resistant lignin and part of the cell-contents, into the amorphous ulmins of group 3 (or products derived from them). There will also be material corresponding with group 2 (a), consisting of altered (but apparently not ulmified) woody tissues, such as compose many lignites and are recognizable in many bituminous coals. We have at present no knowledge as to what becomes of the non-ulmified portions of the cell contents. As they finally appear in the coal, cell-wall structures, group 2 (a), may not differ much chemically from the amorphous ulmins, but the materials of group 1 differ markedly.

Our knowledge of coal does not allow of these anticipations being thoroughly tested. We are, for example, only beginning to obtain evidence of the chemical relationships between the apparently wellpreserved spore exiles and cuticles of coal and those of the original plants. As regards the resins, it has been shown by White® that these can persist apparently unchanged in coals up to bituminous rank, but that in the older coals they show signs of having suffered alteration. It is possible, however, that resins persist without material alteration through-

Loc, cit,

6 U. S. Geol. Surv. Prof. Paper 85 (1914).

The Constitution Op Coal

out the mass of many of the older bituminous coals, for there are occasional inclusions of undoubted resins that can readily be separated from them.

When we consider the contribution to coal of the alkali-soluble amorphous material that forms so large a part of recent deposits, such as peat, a decided difference is at once apparent. The proportion of material soluble in alkaline solutions progressively decreases in the older deposits, imtil from the higher rank bituminous coals and the anthracites little or none can be obtained. Although it has been suggested that the absence of soluble ulmins in the older fuels is due to the fact that their mode of formation was different from that of peat, it can be more simply accounted for by assuming a change in the character of the ulmins, through condensation, dehydration, and loss of carboxyl, resulting in their losing their ''characteristic" solubility in alkaline solutions. This suggestion implies that the amorphous cementing material for the numerous plant structures in coal was originally a soluble ulmin, corresponding to the ulmins that surround and permeate the plant structures in peat. Moreover, its amount should be comparable with that of the soluble ulmins in the older peats.

Chemical evidence of this relationship is not difficult to find. Fischer and his co-workers have been able to demonstrate to some extent the presence of the same groupings and structures in peat ulmins, brown coals, and bituminous coals, and we have found that a close relationship in chemical structure exists between the peat ulmins and a characteristic amorphous portion (vitrain) of bituminous coal, and between the latter and the general ground mass of all portions of bituminous coal. Further evidence of the ulmic nature of much of the coal substance may be found in the "resolution" of coal by prolonged oxidation into soluble "ulmins" (oxidized ulmins) and plant entities in the manner described by Francis and Wheeler.®

Our comparison between peat and coal has concentrated on two substances that show remarkable physical resemblances; viz. dopplerite, from peat, and vitrain from banded bituminous coal. Dopplerite is essentially a homogeneous black jelly, of infrequent occurrence, found in layers at varying depths below the surface of peat bogs. Usually entirely free from plant structure, it sometimes exhibits a faint network of, apparently, cellular structure. From its composition, solubility in alkalis and general chemical behavior it must be regarded as an almost pure form of peat ulmin. To the majority of those who have studied it, its mode of occurrence has suggested that it was formed as a liquid or plastic mass. Several suggestions may be advanced to accoimt for this especial and peculiar occurrence of a peat ulmin: (1) Chance precipita-

Eesolution of Coal by Oxidation; see p. 165,

F. y. TIDESWSiUi AND B. V. WHBELEB

tion (e. Q., by a solution of iron sulfate) of naming dissolved in alkaline solutions produced by the disintegration of rooks; (2) the formation of ulmins directly from solutions of amino-acids and carbohydrates produced by bacterial action from the accumulated vegetable matter, giving first water-soluble and then water-insoluble ulmins; mid (3) interaction of the cdlular tissue and the nitrogenous contents of the plant cells tn situ (probably in general after partial decay) resulting when not quite complete in the network of cellular structure filled with jelly that is sometimes to be observed in dopplerite.

The similarity of form and occurrence of dopplerite and vitrain will be evident. Chemically, the two substances also show certain similarities, with just those differences that would be expected from their different ages. The similarities appear in their products of destructive distillation. The tars from an Irish dopplerite and a Hamstead (Warwickshire) vitrain are of the same type, and the gaseous products, apart from a large and characteristic evolution of carbon dioxide from the younger ulmin, are almost identical, at all temperatures of distillation. The marked evolution of carbon dioxide (together with a large proportion of water) from the dopplerite indicates the presence in the molecule of carboxyl and hydroxyl groups that are easily split off and the differences in composition between the dopplerite and the vitrain can be accounted for entirely by the splitting off of these external groupings. Concomitant with the loss of these oxygenated groupings, we ould expect to find a loss of solubility in alkaline solutions, but an increase in solubility in organic solvents, as the residue approximates more and more closely to a hydrocarbon structiure. This is in fact observed.

We therefore consider that there are ample grounds for the conclusion that vitrain is similar to, though not identical with, dopplerite, and that it represents a more advanced stage in the process that has formed dopplerite from the decaying vegetation.

The proof of the close analogy between peat and coal, supported by the relationship found between dopplerite and vitrain, is completed by a demonstration of the identity of the amorphous material encrusting the plant structures in coal with that essentially free from plant entities, as in vitrain.

The four ingredients of banded bituminous coal — vitrain, clarain, drain, and fusain — show marked differences under the microscope. Vitrain is transparent and essentially free from plant structures;*

Winter: Glvckauf (1922) 58, 1533.

Though free from such structures as spore 'exiles and cuticles many apparent vitrains show the forms of isolated or even generally distributed cellular tissues. These vitrains can be regarded as impure or incomplete. They were perhaps formed in aitn from woody tissue that had not been entirely unified.

The Constitution Of Coal

clara shows numerous and varied structures in a transparent matrix; drain, a large variety of structures in an opaque granular matrix; and fusain consists almost entirely of blackened and thickened cellular tissues.

We have been able to trace a marked relationship chemically between these four ingredients, and puiacularly between vitrain, clarain, and drain, displaying itself in a rular gradation in their composition, in their susceptibility to the action of solvents and reagents, and in their response to heat treatment. Thus, the gaseous products of distillation were substantially identical in composition and varied in the same manner with the temperature of distillation, though the quantities obtained decreased in the vitrain, clarain, and drain in the ratio 1.0 :0.9 :0.7. The same ratio applied to the general "reactivity" of the banded ingredients of the coal. The explanation of this relationship lies in the fact that the ingredients are compounded of two distinct types of substances, the one "reactive," the otW relatively "inert."

The "reactive" material appears to be of a similar nature in each ingredient, so that with the recognition of the essentially uhnic origin of the vitrain, the bulk of it can be considered as "reactive" and it follows that the "reactive" material of the remainder of the coal is also composed of altered (aged) ulmins, which must thus be present to the extent of 90 and 70 per cent., respectively, in the clarain and drain of the Hamstead coal. There seems no reason to doubt the presence in the Hamstead coal (and, by inference, in other bituminous coals) of altered ulmins to this large extent, in complete analogy with the presence of soluble ulmins in peat.

The question then remains as to the function in coal of the organized plant remains that form an apparently considerable part of clarain and drain. There are grounds (from a comparison of woody lignites with dopplerites) for the belief that certain of the plant structures, in particular the cellular tissues, may exist in coal in a form similar chemically to the ulmins. Otherwise, the plant entities must constitute what we have tamed the "inert" material of coal.

Discussion

David White, Washington, D. C. — The idea foreshadowed in the two preceding papers that vitrain is essentially ulmic or humic matter is here more clearly expressed. The plant structures present in it, and which appear as accidental or shadowy residues are, I believe, laiy of a common composition as well as origin with the ulmic decomposition matter, both being of carbohydrate orion.

A. C. Fibldneb, Pittsbui, Pa.~paration by hand of the bright and dull coal bands of several individual samples of banded coal, and chemical analysis and coking tests of these portions have shown rather

Discussion

minor differences in chemical composition. It may be tiiat, in American coals, the differences between brit and dull bands, or clarain and drain, are not so marked as in the English coals. From the similarity of the chemical analjrses, one is led to believe that the greater percentage of the ground mass in both bright and dull coal is of similar composition— that is, a product of ulmic matter.

The principal difference between clarain and drain, or bright and dull coal, is in the coking properties. Typical bright coal, or anthraxylon, fuses completely, but drain, or attritus, does not fuse. Doctor Jeffrey's work suggests following through the transformation of wood into coal with a view to determining the particular stage at which the woody disintegration product takes on itself the properties of fusing and becoming plastic, as in coking coal.

OBOAKIC SULFUB COMPOXmDS IN COAL

Organic Sulfur Compounds in Coal

Bt J. JoUiT* and R. V. WHBBLBBit ShBFFISIiD, Emolano (New York Meetinc, February, 1925)

This short note on the probable character of the organic sulfur compounds in coal can do no more than indicate lines of research. We have no new experimental work to describe, nothing comparable in value with the careful studies of American coals by Powell and Parr and Yancey and Frazer.* A study of the manner in which sulfur compounds exist in British coals (and their behavior on heat treatment) is rendered increasingly necessary by the fact that the British reserves of good coking coals of reasonably low sulfur content are fast being depleted. We believe that it is essentially by a study of the modes of formation, occurrence, and decomposition of the various types of inorganic and organic sulfur compounds in coal that it will be possible, with hope of success, to attack the problem of purifying coals, otherwise eminently suitable for coking, from these objectionable ingredients.

Sulfur, so far as is at present known, does not normally occur in the free state in the coal conglomerate, but is chiefly distributed, irregularly, in three forms:

1. As primary constituents of the coal conglomerate, organic in nature and probably associated with those molecular complexes that have resulted from the degradation of the proteins of the plant tissues responsible for the formation of the coal mass. These constituents can be classed as ''organic sulfur."

2. As metallic sulfides, e.g., iron pyrites.

3. As metallic sulfates, e.g., calcium sulfate and ferrous sulfate. (The occurrence of these compounds varies with the occurrence and degree of degradation of class 2.)

It is usually found that sulfur compounds of class 3, the metallic sulfates, are present in coal in small proportions only, amounting to about 1 or 1.5 per cent, of the total sulfur. The compounds in classes 1 and 2 are therefore of more importance. Class 1 alone will receive considera-

Junior Assistant, Safety in Mines Besearch Board.

t Professor of Fud Technology, Sheffield University, and Director of Research, Safety in Mines Research Board.

Univ. m. BuU, 111 (1919); synopsis published in Trans, (1920) 68, 674.

Univ. m. Butt. 125 (1921).

3 . JOIiLT AND B. V. WHBELBB

tion in this paper, though, when considering the possible forms in which "organic sulfur" can be present in coal, it should be borne in mind that there may be a relationship between the occurrence of these organic complexes and that of the metallic sulfides, which may possibly also owe their presence in coal to the sulfiu* compounds originally present in the vegetation from which our coal measures were formed.

On this subject, we receive help from researches dealing with the sulfur contained in modem plants, more particularly from those relating' to the proteins in cereals. The sulfur in plants resides mainly in the proteins' contained in their seeds (in the germ and its associated food supply), while some proteins are transported through the phloem cells of the living plant tissues. Little is known regarding the latter, because of their transient existence, but botanists have obtained a fair amoimt of success in their endeavors to elucidate the problem of the stracture of the siilfur complexes which are invariably present as an integral part of the seed organs.

Osborne* has investigated the properties of the proteins in a number of cereals and has shown that they differ, in different cereals, in their reactivity under direct chemical attack. For example, on boiling the different seed materials with a 30-per-cent, solution of lead acetate during several hours at a temperature of 165° C., some of the sulfur could be isolated as cystine while the residues contained varying quantities of more stable sulfur compounds. The sulfur isolated as cystine Osborne termed "loosely bound sulfur" and the more stable compoimds "resistant sulfur." The proportions in which these are contained in cereals are indicated by the following data from his experiments:

Pbotbin

Totax. SULVXTB, Pbb .

Loobblt

Bound

Sulfub

(Isolatbd

AS Ctstins), Pbb .

Total

Sultub

as Loobblt Bound, Pbb .

Phaseolin, from the kidney bean

Edestin, from hemp seed

Glycinin, from the soy bean

Gliadin. from wheat

From the results of many experiments, Osborne concluded that, in general, a protein rich in sulfur was not of necessity rich also in those compounds that were acted upon by the reagents he used, and that there was evidence of at least two types of sulfur complexes of different degrees of reactivity.

It seems to be generally admitted that the degradation products of proteins are similar in character whether the proteins be of vegetable or ii.TiiTnn.1 origin. The work of Harris* on proteins of animal ori can

Jtd. Amer. Chem. Soc. (1902) 24 , 140.

Proe. Boy. Soo. (1922) B. 94, 426.

Organic Sulfur Compounds In Coal

tilrefore be drawn upon to supply evidence in support of Osborne's views. Harris found that 89 per cent, of the sulfur in serum albumen could be isolated as cystine, the remainder being stable, while from ovalbumen only 14 per cent, could be isolated as cystine. He foimd, moreover, that the sulfur in proteins only becomes reactive under certain conditions of experiment and in all the organic compounds he investigated a proportion (which varied with the compound) of the sulfur existed in a very stable form. The isolation of the maximum quantity of organic sulfur was only possible imder optimum conditions of experiment, which varied with each compoimd.

The oxidation of cystine, which can be isolated as one of a group of dehydration products of proteins, has been studied and it has been found that its reactivity (and that of its reduction product cystein) can be controlled in a suggestive manner. Cystine is a diamino acid, the disulfide of a-amino /3-thio propionic acid, of the formula:

HaC S S CH2

/ I

HjN.HC CH.NH2

I

60Oh Cooh

while its reduction product, cystein, is a mercaptan. The oxidation of these compounds can be accelerated by the presence of iron in minute quantities, while if a cyanide is also present, as an additional catalyst, the reaction is still further accelerated. For example, the presence of as little iron as M/10,000 was found to double the rate of oxidation. The oxidation process appears to be intra-molecular and the iron to act as an oxygen carrier, being loosely held in combination until the reaction is complete. Another important observation is that the rate of oxidation of cystine is greatly reduced by the presence of a solution of sodium, potassium, or calcium chloride of 4 mol. strength.

Baumann and Goldmann have also studied the behavior of cystine toward reagents and have shown that it is remarkably inert toward many, while with all time of contact is an important factor. For example, in two experiments in which cystine was boiled with a 10-percent. sodium-hydroxide and lead-acetate solution only 68 per cent, of its total sulfur was 3 delded as sulfide after 9 hours treatment and 83 per cent, after 33 hours.

Similarly, experiments by Schultz on the treatment of cystine with a 30 per cent, solution of sodium hydroxide in the presence of zinc and oxide of bismuth, showed that 53 per cent, of the sulfur was obtained as sulfide after 10 hours boiling and 53.7 per cent, after 25 hoilrs.

Matthews and Walker, Jrd, Biol. Chem. (1908) 6, 289.

, physiol. Chem. (1888) 12 , 257.

Ztechr. physiol. Chem. (1898) 25 , 16.

J. Jolly And B. V. Wheelbb

There is thus ample evidence regarding the existence, in the naturally occurring organic sulfur compounds, of groupings containing sulfur that are not readily decomposed and are comparatively inactive; while other groupings yield their sulfur fairly readily, probably as hydrogen sulfide, on treatment with reagents. It would seem also, from the general observations made by different experimenters, that a necessary preliminary to the resolution of the sulfur-containing complexes in proteins, whereby the comparatively unstable compounds are formed, is their partial oxidation.

This evidence of the stability, in favorable circumstances, of certain of the protein sulfur compounds in living plants suggests that some of the sulfur compoimds that were present associated with plant entities that are stUl recognizable in, and can be isolated from, coal may not have been considerably changed during the coal-forming process, and may exist in coal today in a form but little modified. Certainly those parts of plants, cuticles and spore exiles, that can be isolated from bituminous coals do not differ chemically to a great degree from the cuticles and spore exiles of modem plants. The visible plant entities do not, however, often form a considerable part of the coal mass, and there is no reliable evidence that organic sulfur may be concentrated in them. On the other hand, it is presumed that the formation of part of the ulmic groimd mass of coal has been in the first instance by the condensation together, to form amino ulmins, of the carbohydrates and amino acids of the decaying plants. If cystine were involved in such a condensation, sulfur-containing organic compounds might be dispersed throughout the coal-forming mass.

This latter appears to us the more likely hypothesis. It can be elaborated to explain the existence in coal (so evident on its destmctive distillation) of varying proportions of organic sulfur compoimds of different degrees of stability. As a generalization, it may be stated that vegetable tissues when undergoing decay suffer progressive oxidation. The oxidation is no doubt sometimes checked, because of temporary adverse conditions, and may proceed again; or it may be permanently stopped according to the particular environment of the deca3ring materials. We thus have the conditions necessary to promote the resolution of the sulfur-containing complexes in the proteins with the production of a proportion, dependent on the environment, of comparatively unstable compounds. Further, by analogy with the behavior of cystine under the action of catalysts, it can be understood that the action of ferruginous waters on the vegetable material undergoing decay would be to hasten the resolution of the proteins while the action of alkaline waters would be to preserve them.

Here our conjectures cease. The experimental work we have undertaken to test them is designed to estimate the proportions of relatively

OBQANIC BmiTXTB COSCPOTTNDB m COAL

stable and unstable organic sulfur compounds, which imdoubtedly exist in coal and, ultimately, to determine their character.

Discussion

S. W. Pabb, Urbana, 111. — The paper works back to the organic compounds and their probable tsrpes through the medium of sulfur, but our practical interest does not lead us in that direction. We want to know how much of the sulfur is mineral and how much is organic? Fortunately the organic sulfur is not easily dissolved and the mineral sulfur is. By a purely empirical method, dilute ordinary hydrochloric acid, if given time enou, will dissolve the mineral sulfur and not touch the organic sulfur. The separation can be hastened considerably by wanning the solution a little. In the coking of this material, it does not make any difference whether the sulfur is in the mineral or in the organic form.

S15Lbctive Conbubtion In Coal

Selective Combustion in Coal

Bt F. S. Sinnatt,* East Gbbbnwich, England

(New York Meeting, February, 1025 )

This paper is the outcome of an extended investigation carried out in association with Dr. L. Slater. The inquiry had been continued in various directions and a number of results are quoted from an investigation recently completed by S. H. Jenkins. In projecting the work some five years ago, the author had in view a general attack on the problem of the spontaneous combustion of coal from an angle that had received little attention. The basic idea was to obtain a "slow motion study" of the active combustion of coal. This included an examination of the conditions prevailing in a mass of coal at the moment when active combustion ceases. It was thought that, if the factors governing the extinction of combustion in coal could be definitely established, it might offer an explanation of the manner in which the spontaneous combustion of coal originates.

The inquiry arose from a detailed study of the properties of fusain that the author began in 1918. Fusain seemed to possess characteristics quite distinct from the coal with which it was associated, for if it were collected into a heap and one portion were heated by a small flame the combustion would traverse the whole mass. This combustion was not accompanied by smoke and passed slowly through the heap of material. Later, it was found that coals, including anthracites, would behave in a similar maimer provided they were in the form of powder and that the particles were smaller than a certain size. The limiting size of particles is a definite characteristic of the coals investigated. In view of the fact that fusain exists with coal in a state that enables it to undergo this particular form of combustion, it must be assumed, sometimes, to playa definite part in the spontaneous combustion of coal in the goaf (waste).

Tables 1 and 2 contain the analyses of samples of dust collected from a mine and from a dust collector. Some idea of the degree of fineness of the particles of fusain may be obtained from a study of the analyses of the dust from the dust collector; 80 per cent, of the dust would pass through a 200-mesh screen while the fusain was concentrated in the finest dust. The material that passed through a 90-mesh screen contained 64 per cent, of fusain while that between a 30- and a 90-mesh only oon-

Assistant Director, Fuel Research Board.

BBLSCmn! IN COAL

tained 13 per cent. All the samples would propagate a zone of colnbustion when one portion of a heap was heated with a small flame.

Table 1. — Amount o/ Fuaain Found in Mine Duet

Description

Sample

No. 1,

Per Cttat.

Sample

No. 2,

Per Cent.

Sample

No. 8,

Per Cent.

Sample

No. 4,

Per Cent.

Moisture

Ash

Volatile matter

Volatile matter less moisture

Coke...

Fixed carbon

Fusain

Table 2. — Examination of Dust from Duel-collector (Average sample; proximate analysis)

PxB Cent.

Moisture 1.2

Ash 9.1

Volatile matter 22.6

Volatile matter less moisture 21.4

Coke 77.4

Fixed carbon 68.3

Fusain 49

Quantitative Shjvinq Test op the Dust Showed

Above 30-mesh 0.0

30- to 60-mesh 1.5

60- to 90-mesh 3.0

90- to 200-mesh 15.5

Through 200-mesh 80.0

Analyses of Fractions

30- TO 90-BfESH

Moisture 2.1

Arti 7.0

Volatile matter 31.3

Volatile matter less moisture 29.2

Coke 68.7

Plied carbon 61.7

Fusain 13

Through 90-mesh

PsB

.

Moisture 1.2

Aril 9.6

Volatile matter 21.4

Volatile matter less moisture 20.2

Coke 78.6

fixed carbon 69.0

Fusain 54

It may be mentioned that the seams from which these dusts were produced only contained about 1.5 per cent, of fusain.

Pbopagation of Zone of Combustion

The experiments on the propagation of a zone of combustion were carried out in the following manner: Cones of pulverized coal of standard

P. S. Sinnam

size and with uniform packing of the particles were formed by filling a glass funnel with coal and inverting it upon a silica plate (Fig. 1). The coal dust was allowed to fall into the funnel from an orifice placed at a constant level above it, and the excess of coal above the ge of the funnel was removed by means of a broad sharp blade.

The apex of the cone was heated momentarily with a small flame. The combustion thus initiated develops into a zone which passes regu-- larly throughout the mass, provided the conditions mentioned later are satisfied. The combustion is characterized by two well-defined stages: First the color of the coal changes from brown to black, and this is succeeded by a zone in which rapid combustion occurs. The fact that combustion is taking place is not always apparent, as the temperature attained is only sufficient to produce a dull red glow. That the first stage of the combustion is clearly defined was proved by experiments in

Fig. 1. — Propagation op zone of combustion.

which the combustion was allowed to proceed under similar conditions but in a limited supply of air. The combustion is accompanied by little smoke and the odor evolved is similar to that noticed in the early stages of a gob fire.

When the combustion has started in a heap of coal dust, the area may spread until every part, except the portion in contact with the plate on which the coal is standing, has been oxidized. If the combustion proceeds vigorously, some part of the coal may be completely oxidized and ash alone may remain. If the combustion takes place slowly, either because the particles are large or because the supply of air is limited, a cone-like residue is formed. If the residue from the combustion in a restricted supply of air is allowed to cool and one portion of the mass is again heated, a zone of combustion will again travel throughout the heap. This experiment has been repeated four times with one charge of coal; only part of the oxidizable material in the heap is affected during each combustion. The explanation that suggests itself is that each oxidation is a differential one. It is presumed that with more refined experimental methods the number of combustions might be increased. The experiment disproves the belief that when a gob fire has occurred in a certain mass of coal, or in one part of a mine, a second gob fire cannot take place in the same coal or in the same region. There appears to be

Selective Combustion In Coal

no reason why a gob fire should not occur a number of times in the same quantity of coal.

The zone of oxidation may not spread uniformly throughout the heap but may follow a well-defined path and leave the remainder of the coal nearly unaffected. The exact conditions that are favorable to the propagation of a zone of combustion in a particular region cannot be defined accurately at present, but absence of uniformity in the packing of the particles has a marked influence. It is not possible to assume that the combustion follows the path of most open packing, although experiments in which the powdered coal was placed under pressure have shown that the propagation of the zone was then retarded or entirely prevented.

The behavior of the coal during the period of active combustion, i.6., as the zone of combustion is passing, varies not only with the type of coal and the oxygen available, but with the size of the particles. When the oxidation is allowed to proceed in the presence of an excess of air, the mass of coal decreases in volume if the particles are below a critical size. When larger particles are associated with the fine coal, the oxidation is accompanied by a slight increase in the volume of the mass if the coal is a caking variety. It is found that a portion of the coal may undergo more complete oxidation while the residue is partly oxidized and carbonized. The carbonized particles are converted into minute spheres of coke-like material. When the heap has a surface that is vertical or at an angle greater than the angle of rest of the coke-like product, the spheres of the latter will roU from the zone of combustion and may then be collected at the base of the heap. With anthracites, which are non-caking and non-swelling, there is a slight decrease in the size of the heap during oxidation.

Although the oxidation may be proceeding along a definite path, the change in volume produced in the mass at the moment of active oxidation may be such as to prevent the zone of combustion proceeding farther in a particular direction. Only caking coals have been examined in this connection.

Table 3. — Limiting Size of Particles of Three Coals

Anthracite

Arley

Figure of Finenees

Oxidation j

Figure of FineneoB

(Oxidation

Figure of Fineness

Oxidation

Complete -

Complete

Incomplete

Complete

No combustion

Complete

No combustion

Complete

No combustion

F. S. Sinnatt

Table 4. — Values Obtained in (he Screening Testa and Analyses of the

Coals

Hours

Per Cent, on

Per (!Sent. throuAlt 200-mesh

Figure of

Grinding

90-mesh

laO-mesh

150-mesh

200-mesh

Fineness

Ravinb

Ablet

16 !

Mountain Mine

j 16.40

11,11

1,61

Proximate Analyses

Moisture

Aali

Volatile matter

Volatile matter less moisture.

C3oke

Fixed carbon

Ultimate Analyses

Carbon

Hydrogen

Nitrogen

Sulfur

Ash

Oxygen (by difference)

TOL. Lxan. — 18

Mountain

Minb

Abi/BT

Minb

Rayikb

Minb

IM dBtiBcnvs coHBtrBTioN nr coal

Table 3 records the limiting raze of particles for three coals — Arley, Ravine, and an anthracite. The fineness was determined by an exhaustive screening test and is expressed in the terms of the figure of fineness.

With Ravine coal, all samples in a finer state of division than that corresponding with a figure of eness 1.1655 would ignite readily and the combustion would proceed throughout the mass of coal dust. With the Arley coal, the oxidation would proceed over a much wider range, for all dusts finer than indicated by a figure of fineness 1.1684 would ignite and bum completely. Anthracite obtained by grinding during 20 hours (figure of fineness 1.1142; 98 per cent, through 200-mesh) would ignite and the combustion would proceed until the oxidation was complete, but specimens coarser than this could not be made to burn completely. These results indicate that two factors predominate; the character of the coal; and the fineness of division of the coal.

The two bituminous coals show that a sharply defined value exists for the critical degree of fineness necessary to enable the combustion to proceed and indicate that the ratio of surface exposed to the weight of the particles is a factor in deciding whether the oxidation of the coal will proceed autogenously under the conditions postulated. It would appear that experiments on the oxidation of coal by earlier investigators may have shielded erratic results from the fact that the particles of individual specimens of the coal may have been above or below the critical degree of fineness.

Rate op Pbopagation op a Zone op Combustion

It was thought that the rate of oxidation of the dusts might offer means of determining the liability of a coal to spontaneous combustion, so attempts were made to obtain a measure of the rate at which combustion was occurring. The method adopted was to allow the dust to oxidize in a narrow "train" and to note the time required for the combustion to pass from point to point.

A metal trough, 5 in. long, in. in width, D-shaped in cross section and closed at the ends, was used to make the "train" of coal dust. The trough was held in position horizontally beneath an orifice and dust was run into it, in a thin stream, imtil it was filled and overflowing at the sides; the excess was then removed by means of a sharp blade until the coal was level with the edges of the trough. A thin silica plate 7 by 1 in., graduated by a series of lines 1 in. apart at right angles to the longer dimension of the plate, was placed on the trou. The whole was then inverted and placed on a firm base, and the metal trough carefully rranoved so as to avoid any displacement of the coal dust. A heap, or "train, " of coal dust remained on the plate 5 in. long, the same height

FwH in Set, & Prac. (1923) 2, 142.

r. S. SINNATT

ld5

throughout its length, and uniformly packed. The apparatus was protected from drafts. The trough and plate with a train of coal in position are shown in Fig. 2.

The train of coal was ignited at one end by a small flame; the oxidation was found to proceed at a perfectly uniform rate to the opposite end of the train, leaving a residue of coke or of ash according to the method of treatment.

The front of the zone of combustion could be readily followed by observing the sharp color change in the coal dust from brown to black. The time taken for the oxidation to proceed over a definite length of 4 in. of train was determined. The results obtained are given in Table 5.

Table 5. — Rale of Propagation of Combustion

Coal

i r

Hours of 1 Grinding j

Figure of Fineness

Time Ooeupied for Combustion over 4 In., Minutes

Arley

36 ;

1 13 !

9 !

28H

7 !

36K

4 j

42K

No combustion w:

ith larger particles

Mountain mine

20 '

No combustion wi

ith larger particles

Ravine

20 '

22H

Anthracite

Propagation of

combustion along

train did not take place even with

finest powders.

The most finely ground specimens of Arley and Mountain Mine coal required the same period of time (24 min.) to bum over a length of 4 in. of the train, while the Bavine coal for a similar degree of fineness only required 22 min. This indicates a marked readiness on the part of the latter coal to oxidize in the air; a significant observation in vie'w of

SELECmVB COMBUSTION IN COAL

the fact that the Ra-dne coal is liable to undergo spontaneous heating in the goaf.

It will be observed that the results correspond, in general, with those obtained when conical heaps were used. Both the Arley and the Ravine coal dusts failed to propagate a zone of combustion along the train when the sizes of the particles were similar to those that failed to allow of propagation in the heaps; while with the Mountain Mine coal progressive combustion of the particles below the figure of fineness 1.1548 did not occur.

Attention must be called to the great difference in the time required for the propagation with alterations in the degree of fineness of the dusts.

Within the limits of the experiments herein recorded, Arley coal required from 24 min. to 42) min. for the combustion to travel 4 in..

Fig. 2. — Dstebminino bate of propagation op a zone op combustion.

according to the degree of fineness of the particles. In view of this variation, it would not appear possible to standardize the present method of examining the liability of a coal to spontaneous combustion unless the dust is state of division approaching the limiting degree of fineness as indicated by the " figure of fineness. " As the limit of fineness is reached, the rate of combustion along a train assumes a limiting value; and this limiting value for the rate of combustion may afford a measure of the liability of the coal to undergo spontaneous combustion.

The limiting value for the rate of combustion appears to have been reached with one coal only, the Arley, which shows the same rate of combustion for samples ground for 16, 20, and 36 hours, respectively. Mountain Mine and Ravine coals do not exhibit this approach to a limit. Although the combustion proceeds in the train of Mountain Mine coal dust within narrower limits of fineness of the dust than obtains with either Ravine or Arley coals, with samples of comparable fineness the rate of combustion with the Mountain Mine coal is greater than with either of the other two coals. The fact that the limiting vidue for the rate of combustion is suddenly attained with the Arley coal indicates the possibility of there being an equally abrupt approach to the maximum rate of combustion with the other coals as the state of division of the

F. S. 8Innatt

dust particles is increased; and it is necessary that bore anything definite is stated with regard to this particular point a larger number of coals that have been ground during an extended period should be tested.

Modifying Influence of Vakious Compounds on Rate of Combustion

It was considered desirable to examine the modifying influence of the addition of various compounds on the rate of combustion of finely powdered coal under the conditions of the present experiments. As a preliminary experiment, the influence of the presence of finely divided calcium carbonate was investigated. Pure calcium carbonate that had passed through a 150-mesh sieve was intimately mixed in various proportions with Arley coal (figure of fineness 1.1489). These mixtures were formed into trains and the rates of combustion determined in the manner previously described. The results obtained are given in Table 6.

Table 6. — Combustion Rate of Coal and Calcium Carbonate Mixtures

Coal,

1 Calcium Carbonate,

Combustion Time for 4 In.,

Per Cent.

I Per Cent.

Minutes

100 !

It will be observed that increased proportions of calcium carbonate failed to retard the rate of combustion; it required the addition of 70 per cent, of calcium carbonate to prevent entirely the propagation of a zone of combustion.

It was considered of interest to examine the effect of adding finely pulverized rock dust to the coal. Mixtures were made of various proportions of pulverized shale, which had passed through a 200-mesh sieve, and Arley coal of the figure of fineness 1.1370. It was found that the limiting quantity of stone dust in admixture with the coal dust that would just permit of coihbustion passing through the heap was 62 per cent. With a greater percentage, the mixture failed to ignite; while with lower percentages oxidation proceeded regularly throughout the train of mixture.

The possible catalytic effect of the presence of small amounts of ankerites containing manganese and ferrous salts was now examined. For this purpose, admixtures were made with Arley coal of a fineness of 1.1684 (figure of fineness). Coal dust of this size has a very slow rate of burning and was chosen because any increase in the rate of combustion due to catalytic action would be more readily observed. The time

SBIiSCTIVB COMBUSTION IN COAL

IdS

required for the combustion to tnivel in the pure coal dust over a length of 4 in. train was 42 min. When small quantities of manganese and ferrous salts were added the results were:

Mikutbs

1 per cent, manganese catenate 42

1 cent, ferrous sulfate 42H

1 per cent, ankerites from Arley coal

There is apparently a slightly increased rate of combustion in the mixture containing manganese carbonate, but a variation of K uiin. in the measurement of the time is within the range of experimental error.

Tsmpebatube Recorded During Combustion

A platinum, platinum-rhodiiun thermocouple was introduced into a cone of coal dust in the manner shown in Fig. 3, the point of the couple being fixed centrally and in. from the apex. The apex of the cone was ignited, and a record of the temperature was made at 1-min. intervals. The results when using anthracite dust are given in Table 7. Only the values at 5-min. intervals are quoted for the sake of brevity.

Table 7 . — Combustion Temperature of Anthracite

Timb,

Mikutbs

C.

Timb,

Mikutbs

C.

Similar results were obtained with other coals, thus: Arley having a figure of fineness of 1.1370, the temperature reached 485° C. and remained stationary for 2 min. then rose to a maximum of 510° C. Ravine having a figure of fineness of 1.1350, had a gradual rise in temperature to 480° C., where it remained stationary for 2 min. then rose to a maximum of 540° C. Mountain Mine, having a figure of fineness of 1.1413, had a gradual rise to 450° C., where it remained stationary for 2 min. then rose to 510° C. maximum.

In each instance a maximum temperature is recorded varying from 510° to 585° C., and in the combustion of bituminous coals two distinct stages can be recognized marked by a pause in the rise of temperature. No stationary intermediate temperature could be detected with anthracite, but the rate of increase of the temperature became slower between 520° and 550° C. The fact that a first and second mitTiTniiTn are observed lends some support to the theory that a dual oxidation is proceeding.

The ilaM fu&sd shown was not used in this series ci oiperiments.

P. S. Sinnatt

It is apparent that| other factors remaining constant, the ma in consideration which decides the oxidation of the coal is the rate at which the oxygen is able to react with the organic substances. Certain of the factors have already been discussed, and it is now proposed to consider the effect of variations in the oxygen supply.

Experiments were carried out with a cone of coal (Arley coal, figure of fineness 1.1370). The air was controlled by means of a funnel which was placed over the cone of coal as shown in Fig. 3. This funnel nor* mally fitted closely to the glass plate upon which the cone of coal rested, and the air supply could be controlled by raising it above the glass plate. The height of the funnel from the glass plate was regulated by interposing between the edge of the funnel and the plate different numbers of very thin glass micro-cover slips. In the experiments to be described.

Fig. 3. — Determining temperature during combustion.

the coal dust was placed in position upon the glass plate in the manner already explained; the apex of the cone of coal was ignited, and the outer funnel placed in position resting over the cone of coal and maintained the distance of one cover-slip thickness from the glass plate. Thirty seconds after placing the funnel in position, the smoke that had been given off from the tip of the cone on first ignition ceased to be evolved. Moisture was deposited upon the inner surface of the funnel, and the oxidation spread regularly to the base of the heap, as could be detected by the change in color of the coal. The maximum temperature observed during the combustion was 280® C. The gases issuing from the stem of the funnel possessed a characteristic odor, apparently due to the presence of acetone. When the combustion had spread to the base of the heap, the funnel was removed and the heap of coal scattered upon the glass plate. Vigorous combustion immediately took place over the scattered

SELGCnVB OOMBtTSTION IN COAL

surface, various points reaching a temperature of 800° C. In a second experiment, combustion spread, throughout the coal and again reached a temperature of 280° C., when further oxidation ceased. After the heap had assumed the normal room temperature, the funnel was removed and the heap cut into sections and examined. At no point could complete combustion resulting in the production of ash be observed. This is a distinctly different result from that obtained when the coal was allowed to bum in an excess of air. It would appear that with bituminous coals a preliminary oxidation occurs in which some very readily oxidizable constituent actively reacts with a comparatively limited supply of air.

Fig. 4. — Appabatus poe controlled oxidation of coal.

Further tests were performed with the same apparatus supplying increasing volumes of air to the coal, by inserting two or more glass micro-cover slips between the funnel and the glass plate. It was found that the combustion could be modified until, with an excess of air, the coal oxidized completely.

Investigation suggested a container which allowed the oxidation to proceed as in the small conical heaps but in a controlled manner. A sectional diagram of this container is shown at (a) Fig. 4. It consists of a thin metal cylinder A, in. long, provided with a close-fitting lid and having an outlet at B and three short tubes at C placed vertically below

P. S. Sinnatt

one another and 1 in. apart. The outlet from the lid is at /). A thin metal collar £ is soldered on the inside of the cylinder A and to this is soldered a cylinder made from 100-mesh gauze, which fe in. smaller in diameter than A and 4 in. long. The gauze cylinder is pierced with holes cutto fit the thermometers F that pass through the side tubes C. A disk of 100-mesh gauze is soldered inside the cylinder A, in order to distribute evenly the air supplied. The general arrangement of the apparatus for carrying out an experiment is shown in Fig. 4, and needs no description.

An experiment was carried out in the following manner. Three thermometers F were inserted through the side tubes C, and held in rubber stoppers so that the bulbs were centrally placed along the axis of the gauze cage. Coal dust was gently poured into the cage from an orifice placed at a definite height above the top of the cylinder A until the gauze container was filled to the height G. A supply of air (at a definite rate) was passed through the inlet, and the tip of the cone of coal above the level G was ignited by means of a small gas flame. The lid was placed in position and the joint made gas-tight. The temperatures recorded by the thermometers were noted at 5-min. intervals; the results are given in Tables 8 to 11. (To simplify the tables only essential readings are quoted.)

It will be observed that in each experiment the thermometers in turn indicated a maximum. When an experiment was completed the thermometers were withdrawn, the product remaining in the gauze cage removed and examined as in the previous series of experiments. The

Table 8 . — Rate of Air Supply 4412 Cubic Centimeters per Hour

Time

Thermometer Readings, Degrees C.

Fx

Ft

3:0

3:16

3:20

3:26

134 (max.)

3:30

4:0

4:16

4:20

4:26

111 (max.)

4:66

6:0

6:06

6:10

132 (max.)

6:16

6:30

20S

SXXBCnVB COKBtJSTION IN COAL

Table 9 . — Rate of Air Supjiiy 4491 Cubic Centimetere per Hour

Time

Thermometer Reedinge, Degrees C.

Ft

3:45

3:55

4:05

4:10

167 (max.)

4:45

5:0

5:10

131 (max.)

5:30

5:45

5:55

148 (nkx.)

6:30

7:10

Table 10 . — Rate of Air Supply 6000 Cubic Centimetere per Hour

Tiuiv

Thermometer Readings, Degrees C.

Fi

Ft

2:05

2:30

2:40

182 (max.)

! 31

3:15