WINCR SS r) , ‘ Pike’ ‘* Pi) alias aay ays _. lt sone titi ihe «(hea r a & q [ i Bens te ay as ANNUAL REPORT OF THE BOARD OF REGENTS OF THE SMITHSONIAN INSTITUTION SHOWING THE OPERATIONS, EXPENDITURES, AND CONDITION OF THE INSTITUTION FOR THE YEAR ENDING JUNE 30 1920 (Publication 2622) WASHINGTON GOVERNMENT RRINTING OFFICE 1922 “O ITUTITE A seh ineee ‘ Mh ‘ A ; CA gasurianisxa BAOITARIIO 2 WOITUTITEML IHT 40 WOITIAMOD a Ot AVUL OVIGAd TARY THT AOT LETTER FROM THE SECRETARY OF THE SMITHSONIAN INSTITUTION SUBMITTING THE ANNUAL REPORT OF THE BOARD OF REGENTS OF THE INSTITUTION FOR THE YEAR ENDING JUNE 380, 1920. SMITHSONIAN INSTITUTION, Washington, April 13, 1921. To the Congress of the United States: In accordance with section 5593 of the Revised Statutes of the United States, I have the honor, in behalf of the Board of Regents, to submit to Congress the annual report of the operations, expendi- tures, and condition of the Smithsonian Institution for the year end- ing June 30, 1920. I have the honor to be, Very respectfully, your obedient servant, Cuartes D. Waucort, Secretary. 3 CONTENTS. Page. Letter from the secretary, submitting the annual report of the Regents fo) LOT aK es es SR Ne ee ee eS ee ee eee ee i ee Se 3 eeeHtS OF ENG TCDORE.-- Se iuseeceee Be 8 5 BETS La tan Se ee Se 6 cone ite ego tes py Ti Gener Subiects OL tne Onna): Tenor 2 Semis s S82 9 Oincrals of theinstitution and its branches 2 42ee_ be es 11 REPORT OF THE SECRETARY. Bo Sma LEsonian. Institution, ses 5 tee ie Be ee a 13 ebhe GS Rsta DlSHMeEeN fies. FFs oS me eh ee 25 Re Una toa ee a cp PE a pe 26 Winchonar Botanical Statiou:.- -2 2.2 Seek ee oh 26 Exhibition of South American historical documents____-_________-__~- 27 Research tin tropreay “AMeriCA cee oe we LE Be Spy pa et 27 12qn] oj hteh yoko) 1\- ee Creer TRIS C2 ye eee Re SOREN Pegi SPSS Sc eee oe ee ee ee ee PAS READ AearT yp et SR a SO dS we 2g Re Bo a ea 748) LSP LONGEST IDI IT STE 00 ne SE SIONS, MN OTS NETO Lee eee 2 eee 29 Buream ete American: Wthnology,.-e<7 ARTS 8h Ss a ae gS 31 JN RES 06, Ii ayo NAS tho. os OY o hs fee a Tp Dc eee rege 32 Na LIOn el Wan OlOCI Ga] Par ik 42 a2 ee es Fg = PN Sp ee one 33 MISCO SICH OUSEEVALOTY 2. = PE ee egy ES eg 34 International Catalogue of Scientific Literature_______________-________ 35 ES FEY Cura C0) 2 aa eee eri pe er RRL Rf NS Oe et PE oe 36 Appendix 1. Report on the United States National Museum______________ 37 2. Report on the Bureau of American Ethnology____------___- 57 3. Report on the International Exchanges___-_________________ 73 4, Report on the National Zoological Park _____-___-_____-_-_- 85 5. Report on the Astrophysical Observatory———-——_—_________~- 101 6. Report on the International Catalogue of Scientific Literature_ 108 fee enor On) EMes i Dia isye=etes see hE Ye 112 SBE Spor One pul Ce iOliget ets sa tiee 7 pce ee ee a Elly 5) CONTENTS, EXECUTIVE COMMITTEE AND BEGENTS. Page. meport,of Executive: Committee sscre eee ree ee a 123 Proceedings Of Board.ot herentc ee ae ee eee oe eee 127 GENERAL APPENDIX. Studying the sun’s heat on mountain peaks in desert lands, by C. G. PANT) 01 0 es SR eles eee ce PORES Fe nee Pee EA Ce eee a sh ele 145 The habitability of Venus, Mars, and other worlds, by C. G. Abbot_______ 165. (CIC T a RASS Db 0X8) gal ged eae yh 0 2) ee edge el ee ge teeta 173 A bundle of meteorological paradoxes, by W. J. Humphreys_____________ 183 The determination of the structure of crystals, by Ralph W. G. Wyckoff. 199 Dr. Aston’s experiments on the mass spectra of the chemical elements, Within rodUCeon: Py7O@. Gee AIO Ges ee eee mene ee ne ae 220 AVGH has aT oC Oa Vd pea Be 1B ot ogy 0 Wee eters COUN ON SU RS SE uae ee 241 Soil acidity—its nature, measurement, and relation to plant distribution, Dy Hd ear OW Herr yee ee eres oy eee 247 The chemistry of the earth’s crust, by Henry S. Washington___________ 269 Major causes of land and sea oscillations, by E. O. Ulrich______-______ a21 MherBryoz0a,.0f Messanimalss bywnss, basslen= === na er eee 339 ‘ithe horned dinosaurs, by Charles W. Gilmores=2= ==) eee 381 IRINA ANGay Thay Gen ADD CNM a Nien ened abl Cel Binet yaaa RR aS ee alae a 389 Parasitism and symbiosis in their relation to the problem of evolution, byniadurice Calle ry sess ae ae as Re ee ee ee eee 399 Local suppression of agricultural pests by birds, by W. L. McAtee________ 411 Tyre occult sensesin birds, by: Herbert Hy beck! 22 = eee 439 Adventures in the life of a fiddler crab, by O. W. Hyman_______________ 443 amhe Scuses Of ISects; Dy IN; Li; Melndoos = hee ees ee ee eee 461 The resplendent shield-bearer and the ribbed-cocoon-maker: Two insect Inhabitants of the vorehard, by) Bu Het SoOO ST asm een weet cee eee eee 485 The origin of insect societies, by Auguste Lameere_____________________ 511 The botanical gardens of Jamaica, by William R. Maxon___-____________ 523 Narcotic daturas of the Old and New World; an account of their remark- able properties and their uses as intoxicants and in divination, by ASAD AOS H COW DST IO ON oD annals eldest peels reo n ots tehye eee ea LA EL Gl le 537 Effect of the relative length of day and night on flowering and fruiting of plants; by" W. W. Garner and, Ef. A> Allard]: =08s= eee 569 Fire worship of the Hopi Indians, by J. Walter Fewkes___-__-______--___ 589 Racial groups and figures in the Natural History Building of the United States National Museum, by Walter Hough__~-_--___________-__-____ 611 Notes on the dances, music, and songs of the ancient and modern Mexi- CPTI ANS 6d) Oy abara UES DESY M ehint © (YOU 6 eapeae peer et Sep gn ep ep 657 The Ralph Cross Johnson collection in the National Gallery at Wash- ington, WD C.. ys GeOngeriss LOSCs saa ae ee eee 679 LIST OF PLATES. Tacing page. Secretary’s Report: 1 EASY i ay rtd Le SAG ak ge Oe ne oe 50 Sun’s Heat (Abbot) : LEY ICY TE 7 Lowe ed te lard 148 LEA oh, aaa eR Ries, Bek Te 154 1 EcG CESS) a: A ee a ee 156 Este gens eee te Te 158 AOS Gets (oe een ee ae 160 Venus, Mars, and Other Worlds (Abbot) : SUE es 5 eee Be EPO Se eee 165 1 Ed En et Ei ee ea a 168 Structure of Crystals (Wyck- off) : PANGS =e Se ees eS 200 Blaite (oie mete eh eres peel jb tw 206 PIAtenG 22S - seA eel 210 LEI h acer Agee aie Ree Ses nae ene 213 Mass Spectra (Aston) : LEED (Wout | A 2 ie oe a 235 Soil Acidity (Wherry) : 121 evil Ree oe a 252 LET a oer StS i pee er 268 Bryozoa (Bassler) : PlQtes dee ee eee 3880 Horned Dinosaurs (Gilmore) : LEG (ayia LAS eee een Bee 388 Suppression of Pests by Birds (McAtee) : 12) Br) ih Re ace Re eee 414 125 Ch Siete a A Nl 422 2 ETUC Re eae SOP 430 Fiddler Crab (Hyman): LEAT ers hi IER a eye 450 Plates Gh awh etary ly) 22h 452 a eae ry One ee I ee 456 Senses of Insects (MecIndoo) : LERLS| een ee Ree eM pee Ue 466 Two Orchard Insects (Snod- grass): 12 ESTs [8 eee aN gee ae mg 510 Facing page. Botanical Gardens of Jamaica (Maxon) : | 2 E Ty e a —} | em ae ne pe he tee 536 Daturas (Safford) : Plates! tous tas Ae Bie 568 Effect of Light on Plants (Gar- ner & Allard): PINES WANG 22a 588 Fire Worship (IFewkes) : Pla te Are hatnceey in Be 592 | dal CaN ae Aa BoM Ue Joe CPR Ps a 594 | 2 Ey Sn a Ga er 596 PALES AO ues ee es aa 598 Plates: Q=11, Ss) se 0 ee 604 IPIRGESHID 1S 3 Pe Pe ee 608 Racial Groups (Hough): Plateswa—¢o 22) Se ee 614 PATS eee eee 616 PTATeS HO) QU wees aay eee 618 Plates: lati Gite 620 Plates 31720 eee oe oe 622 Blates 21S hee as 626 Plates: 20-34 2 ase 628 PIateSi D0; O02 ee, eee 630 el SL hot AS alls (a ae eet el 632 Pilates: 39-42... eee 634 Plates 435-48 2 ee 636 Plates: 40-2 eee 640 TACOS ws Oo ea eee eee 642 Plates 50-64-20 644 Plates sGo-GSt 2. Se 646 PIatesiGO=74 2h te 648 Pilates fo, Ole. ee 650 PIateswitso0 fe ee ee 652 Platesssi-Ot ee ee 654 Mexican Dances (Genin) : Plates) s1=10 See 678 Johnson Collection (Rose) : Plates daa Sess ee 690 pean CATAL WD) eran gute gh {ea O ARAM, , od cama, Tey eee ted Pies te: Jerk Af »Jteag, te iu ee Ne RE IEG aera ON, pie a van toch Nea puta eke: ahd bt STARR H I ZOhely " ‘ hae (“4 + Son Aly Mere waMe: eM Bess : an ae wee, : (alaos 4 ROM | GOP ae ai ancl wilh en ae . o a ) ‘ f“I> so3el4 i (wohelohe), speed tee | al P Wi (Sesh) dopatinn) tito 7 OOF she. . ae ee ANNUAL REPORT OF THE BOARD OF REGENTS OF THE SMITHSONIAN INSTITUTION FOR THE YEAR ENDING JUNE 30, 1920. SUBJECTS. 1. Annual report of the secretary, giving an account of the opera- tions and condition of the Institution for the year ending June 30, 1920, with statistics of exchanges, etc. 2. Report of the executive committee of the Board of Regents, exhibiting the financial affairs of the Institution, including a state- ment of the Smithsonian fund, and receipts and expenditures for the year ending June 30, 1920. 3. Proceedings of the Board of Regents for the fiscal year ending June 30, 1920. 4, General appendix, comprising a selection of miscellaneous me- moirs of interest to collaborators and correspondents of the Insti- tution, teachers, and others engaged in the promotion of knowledge. These memoirs relate chiefly to the calendar year 1920. ] PAOTAL YO SPT Pa ine 8 peg hi TAK, THE SMITHSONIAN INSTITUTION. June 80, 1920. Presiding officer ex officio.—Woopvrow WILSON, President of the United States. Chancellor—Epwarp DouGcLAss WHITE, Chief Justice of the United States. Members of the Institution: Wooprow WItson, President of the United States. THomAS R. MARSHALL, Vice President of the United States. Epwarp Dovuerass WHITE, Chief Justice of the United States. BAINBRIDGE Corpy, Secretary of State. Davin F. Houston, Secretary of the Treasury. NEWTON DIEHL BAKER, Secretary of War. A. MITcHELL PALMER, Attorney General. ALBERT SIDNEY BURLESON, Postmaster General. JOSEPHUS DANIELS, Secretary of the Navy. JOHN BARTON PAYNE, Secretary of the Interior. Epwin THomAs MEREDITH, Secretary of Agriculture. JOSHUA WILLIS ALEXANDER, Secretary of Commerce. Wi11aAmM BaucHop WILSON, Secretary of Labor. Regents of the Institution: Epwarp DouGcLass WHITE, Chief Justice of the United States, Chancellor. THOMAS R. MARSHALL, Vice President of the United States. Henry Casot Loper, Member of the Senate. CHARLES §. THomAs, Member of the Senate. Mepitt McCormick, Member of the Senate. LEMUEL P. PApGrTT, Member of the House of Representatives. FRANK L. GREENE, Member of the House of Representatives. Joun A. Eiston, Member of the House of Representatives. ALEXANDER GRAHAM BELL, citizen of Washington, D. C. GEORGE GRAY, citizen of Delaware. CHARLES F, CHOATE, Jr., citizen of Massachusetts. JoHN B. HENDERSON, citizen of Washington, D. C. Henry WHITE, citizen of Maryland. Rogert 8. Brooxines, citizen of Missouri. Hzecutive committee—GrorcE GRAY, ALEXANDER Cuecien BELL, Henry WHITE. Secretary of the Institution—CuHARLES D, WALCOTT. Assistant Secretary.—C, G. ABBOT. Chief clerk.—HaArry W. DORSEY. Accounting and disbursing agent.—W. I. ADAMS. Hditor.—W. P. TRUE. Assistant librarian.—PavuL BROcKETT. Property clerk.—J. H. HIt1, : ist 12 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926. THE NATIONAL MUSEUM. Keeper ex officio-—CHARLEs D. WALcortT, Secretary of the Smithsonian Insti- tution. Administrative assistant to the Secretary, in charge.—W. DE C. RAVENEL. Head curators.—WiILiiam H. Hotmes, LEONHARD STEJNEGER, G. P. MERRILL: Curators.—PAUL BaArTscH, R. S. BAssiter, T. T. BELOTE, AUSTIN H. CLARK, I’. W. CLARKE, F. V. CovintgE, W. H. DaLt, WALTER Hoven, L. O. Howarp, ALES HrRpiiéKa, Net M. Jupp, FREDERICK L. LEwTon, GERRIT S. MILLER, Jr., CARL W. MITMAN, ROBERT RIDGWAY. Associate curators.—J. M. AtpricH, C. W. GILMoRE, W. R. MAxon, CHARLES W. RicHmonp, J. N. Rose, WALDo L. Schmitt, Davin WHITE. Curator, National Gallery of Art —W. H. Hotmes. Chief of correspondence and documents.—H. 8S. Bryant. Disbursing agent.—W. I. ADAMS. Superintendent of buildings and labor.—J. S. GoLDSMITH. Hditor.-—Marcus BENJAMIN. Assistant librarian.—N. P. ScupprEr. Photographer.—ArtTHUR J. OLMSTED. Property and shipping clerk.—W. A. KNOWLES. Engineer.—C. R. DENMARK. BUREAU Ob AMERICAN ETHNOLOGY. Chief—J. WALTER WEWKES. Hthnologisis—JoHNn P. Harrineron, J. N. B. Hewitt, Francis LA FLESCHE, TRUMAN MICHELSON, JAMES MOooNEY, JOHN R. SWANTON. Editor.—STANLEY SEARLES. Librarian.—ELia LEARY. Tilustrator.—Deg LANcEY GILL. INTERNATIONAL HXCHANGES. Chief cleri:—C. W. SHOEMAKER. NATIONAL ZOOLOGICAL PARK. | Superintendent NEp HoLLIstTeEr. Assistant Superintendent.—A. B. BAKER. ASTROPHYSICAL OBSERVATORY. Director.—C. G. ABBOT. Aid.—F.. E. Fow te, Jr. Assistant.—L. B. ALDRICH. REGIONAL BUREAU FOR THE UNITED STATES, INTERNATIONAL CATALOGUE OF SCIENTIFIC LITERATURE. Assistant in charge.—LEoNARD ©. GUNNELL. ———-s- REPORT OF THE SECRETARY OF THE SMITHSONIAN INSTITUTION, Cuartes D. Watcortrt, FOR THE YEAR ENDING JUNE 30, 1920. To the Boarp or Recents oF THE SMITHSONIAN INSTITUTION. GENTLEMEN: I have the honor to submit herewith the annual re- port on the activities and condition of the Smithsonian Institution and its branches during the year ending June 30, 1920. An account of the affairs of the Institution itself, together with a summary of the work of the several branches, are given on the first 26 pages of this report, while the appendixes are devoted to more detailed ac- counts of the operations during the year of the National Museum, the Bureau of American Ethnology, the International Exchange Service, the National Zoological Park, the Astrophysical Observatory, the Smithsonian Library, the International Catalogue of Scientific Lit- erature, and an account of the publications of the Institution and its branches. THE SMITHSONIAN INSTITUTION. THE ESTABLISHMENT. The. Smithsonian Institution was created by act of Congress in 1846, according to the terms of the will of James Smithson, of Eng- land, who in 1826 bequeathed his property to the United States of America “to found at Washington, under the name of the Smith- sonian Institution, an establishment for the increase and diffusion of knowledge among men.” In receiving the property and accepting the trust Congress determined that the Federal Government was without authority to administer the trust directly, and therefore con- stituted an “establishment,” whose statutory members are “the Presi- dent, the Vice President, the Chief Justice, and the heads of the executive departments.” 138 14 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. THE BOARD OF REGENTS. The affairs of the Institution are administered by a Board of Regents whose membership consists of “the Vice President, the Chief Justice, three Members of the Senate, and three Members of the House of Representatives, together with six other persons other than Members of Congress, two of whom shall be resident in the city of Washington and the other four shall be inhabitants of some State, but no two of them of the same State.” One of the regents, usually the Chief Justice, is elected chancellor by the board, and a suitable person is chosen by them as secretary of the Institution, who is also secretary of the Board of Regents and the executive officer directly in charge of the Institution’s activities. During the year Senator Medill McCormick was appointed a regent to succeed Senator Hollis, whose term as Senator had expired. Representative John A. Elston was appointed to succeed Representa- tive Scott Ferris. Representatives Padgett and Greene were reap- pointed as regents, and Charles F. Choate, jr., was reelected a citizen regent by the Congress. The roll of regents at the close of the fiscal year was as follows: Edward D. White, Chief Justice of the United States, chancellor; Thomas R. Marshall, Vice President of the United States; Henry Cabot Lodge, Member of the Senate; Charles S. Thomas, Member of the Senate; Medill McCormick, Member of the Senate; Lemuel P. Padgett, Member of the House of Repre- sentatives; Frank L. Greene, Member of the House of Representa- tives; John A. Elston, Member of the House of Representatives; Alexander Graham Bell, citizen of Washington, D. C.; George Gray, citizen of Delaware; Charles F. Choate, jr., citizen of Massachu- setts; John B. Henderson, citizen of Washington, D. C.; Henry White, citizen of Maryland; and Robert S. Brookings, citizen of Missouri. The board held its annual meeting on December 11, 1919. The proceedings of that meeting, as well as the annual financial report of the executive committee, have been printed as usual for the use of the regents, while such important matters acted upon as are of public interest are reviewed under appropriate heads in the present report of the secretary. A detailed statement of disbursements from the Government appropriations under the direction of the Institution for the maintenance of the National Museum, the National Zoological Park, and other branches will be submitted to Congress by the secre- tary in the usual manner in accordance with the law. GENERAL CONSIDERATIONS. The usual routine operations of the Institution in the “increase and diffusion of knowledge among men” were continued during the REPORT OF THE SECRETARY. 15 year, including a mass of correspondence with individuals and scien- tific establishments throughout the world. It is becoming increas- ingly difficult for the Institution with its extremely limited funds, in the face of greatly increased costs in every phase of its activity, to carry on effective work. However, in spite of the fact that the Institution’s endowed funds have never been materially increased, it has been possible in some measure to advance knowledge and publish the results of scientific work, as noted in the following report on the year’s activities, It is my sad duty to note here the death during the year of Mr. Charles L. Freer, of Detroit, an irreparable loss to the art interests of the country. As stated in previous reports, Mr. Freer presented his unrivaled collections of American and oriental art to the Smith- sonian Institution in 1906, and provided $500,000 (later increased to $1,000,000) for the erection of a suitable building to house the collec- tion. This building is now practically completed and nearly ready for the installation of the collections. That Mr. Freer did not live to see the fulfillment of his splendid art gift to the Nation is greatly to be regretted. An interesting article by Miss Katharine N. Rhoades on the recent additions to the Freer Collections appeared in Art and Archeology, October, 1919. In addition to allotments for the maintenance of the Smithsonian solar observing station at Calama, Chile, several small grants for original research have been made from the Hodgkins fund of the Tnstitution—one to Dr. L. G, Hoxton, professor of physics at the University of Virginia, for research on the Joule-Thomson effect in various gases; another to Mr. Alexander Wetmore, of the Biological Survey of the United States Department of Agriculture, for carrying on investigations of the body temperatures of birds; and a third to the Austrian Meteorological Association for the purpose of aiding in continuing the publication of the Meteorologische Zeitschrift and for the support of the meteorological observatory on the Sonnblick. Both of these were in danger of being discontinued on account of lack of funds, and their cessation would have been a great loss to meteorology. Working also under a grant from the Hodgkins fund, Prof. Robert H. Goddard, of Clark College, continued his researches on a multiple- charge rocket for reaching great altitudes mentioned in last year’s report. The early results of his experiments were published during the year by the Institution under the title “A Method of Reaching Extreme Altitudes,” in which Prof. Goddard showed that it would be perfectly possible by means of his new type of high-efficiency rocket to send recording instruments to the hitherto unknown upper layers of the atmosphere and to provide for their safe return, thus 16 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. obtaining new data of the greatest interest and scientific value to meteorology and solar physics. Prof. Goddard also showed that it was theoretically possible to send a mass of 1 pound of flash powder outside the earth’s attraction and to the dark surface of the new moon, where, on impact, the flash would be visible through tele- scopes on the earth. This interesting speculation aroused great popular interest throughout the country, almost to the exclusion of the immediately apparent scientific value of the experiment, namely, the exploring of the unknown upper layers of the earth’s atmosphere. Prof. Goddard was working on the further development of his re- searches at the close of the year. An important event in the art development of the country will be the creation of the National Gallery of Art as a separate adminis- trative unit under the Smithsonian Institution, to take effect at the first of the coming year, instead of, as at present, a division of the National Museum, which action is made possible through a small appropriation in the sundry civil bill for 1921. Mr. W. H. Holmes, at present head curator of the department of anthropology in the Museum, will be appointed director of the National Gallery. FINANCES. The investments of the Institution are as follows: Deposited in the Treasury of the United States under authority OipA WOT TOSS ea: 2 as Pea ee oT ee ea gi ee eee $1, 000, 000. 00 CONSOLIDATED FUND. American Telephone & Telegraph Co. 4 per cent collateral trust Dondsi due July aslO29 ees tO ee a = 15, 680. 00 Province of Manitoba 5 per cent gold debentures, due Apr. 1, TODD se es ae AER ee pee a cote ea ee bo ee eee 1, 985. 00 West Shore Railroad Co. guaranteed 4 per cent first-mortgage ENCOUN SL UL eSNG 9 TN eae eh De a se 37, 275. 00 Cleveland Electric Illuminating Co. first-mortgage 5 per cent goid DOTS GUCPAPE! Py POGOe mee ae RN SNE Be eae el eee 9, 430. 00 UnitedeStatesiirst Biberty loan. ees spe ee ee 200. 00 United’ States second/iberty loan == eee eee 100. 00 United: States third Liberty loan?=: 24520 e0 oe es ee ee ee 10, 150. 00 Untied’ States: fourtia, Qi er try, lot ra a ee eae ae 50. 00 United= States: Victory, losin 2 oat ae ee eS ee ee 4, 341. 64 United States war-savings stamps, series of 1918_______________ 100. 00 Brooklyn Rapid Transit Co. 5 per cent notes, due July 1, 1918___ 3, 500. 00 Redeemed bonds, excess cost over par___---~-~-------__---___- 134. 88 1 is RES OCS SE ee Sees pee eee ee 82, 896. 02 REPORT OF THE SECRETARY. 17 The sum invested for each specific fund and the manner in which held is described as follows: Fon. [Vale cit| Somplgtad | a PHPMMSED CARY ins oo ne cwictt cecas tes eeesceeewcssseet eee $727, 640. 00 $1,304.00 $728, 944. 00 Hepes fend. 2d oho pelt at cay separa ood POD00s) ase pesackie ts 500. 00 Smiter PNG a ree ans oa ee eee ee 2,500. 00 500. 00 3,000. 00 PP ORINS PENOGPAING CR cen nce cap hens eewes aaces 116,000. 00 37,275.00 153, 275. 00 PAP MMESPPCIIC TONG © <2 = oe suis se oo etc as sa ciaw Hote oe 100,000.00}. erase este scot. . 100, 000. 00 EMAL No Ss Se ea a) eek ne Sh ckc sea eee sae 590. 60 117.00 707.00 STS TEE EY et SEN RR I MORRIS PRE: We 18 14,000. 00 16, 898. 84 30, 898. 84 Momsen T. Heid fand. - 0222220522: SEA re Me Re Ls 11,000. 00 2,150.00 13, 150. 00 Hucy Ll. and George W. Poore fund 2.22.20. 2... 26, 670. 00 4,968. 00 31, 638. 00 Georrerk. santord fund.) 62. S22 cs secg he ee sec Foe 1,100.00 221.00 1,321.00 ehamboriain find a qos ewe So Sade he oe Stes Sess eee tea Oot 10, 000. 00 10,000. 00 OT LPL SCTE 0s SS SMS pe Cece ne otro eg aS | Rea RE 8, 355. 93 8,355. $3 REM AEYAING CNG ooo eo elo oe oc cance eas ose ce sari nalecsue = EE 1,106, 25 1,106. 25 BRR eee eee taneas peace taeane 1,000, 000. 00 82, 896. 02 1, 082, 896. 02 The $3,500 par value of the 5 per cent gold notes of the Brooklyn Rapid Transit Co. are still held in the hands of receivers, no plan of reorganization of the company having yet been decided upon. Mr. B. H. Swales, honorary custodian, section of birds’ eggs, has contributed an additional $300 to the Institution for the purchase of specimens, making a total contribution of $600 since January, 1919. Several small lots of unimproved Jand near Lowell, Mass., have been sold, and $440.07 was realized therefrom and invested for ac- count of the Lucy T. and George W. Poore fund. Dr. William L. Abbott has contributed $4,000 during the year to the maintenance of a field party, the purpose of which is to procure archeological and natural history specimens in Australia. This sum is in addition to an unexpended balance which Doctor Abbott had previously furnished for similar work in Borneo and Celebes. The Institution has received for specific activities valuable con- tributions from Mr. John A. Roebling and the Rockefeller Founda- tion, the amounts being $11,000 and $2,500, respectively. Current funds not immediately required for expenditure are, when conditions will permit, deposited on time in local trust companies and draw 3 per cent interest per annum. The interest received in this manner during the year amounted to $1,320.60. The income during the year, amounting to $171,788.35, was derived -as follows: Interest on permanent investments and other sources, $65,651.37; repayments, rentals, publications, etc., $14,525.09; con- tributions from various sources for specific purposes, $41,171.82; bills receivable, $50,000; proceeds from sale of real estate, $440.07. 42803 °—22——2 18 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. Adding the cash available July 1, 1919, $2,122.78, the total resources for the year amounted to $173,911.13. The disbursements, which are described in the annual report of the executive committee, amounted to $160,606.79, leaving a balance on deposit with the Treasurer of the United States, in cash and in bank, amounting to $13,304.34. The Institution was charged by Congress with the disbursement of the following appropriations for the year ending June 30, 1920: Miernational: -Hixehanees] 2s see are ke tes 2s she ee ee a ee $45, 000 PATTER LCAIY BA GEIIT OUR ns cs eee eee es dete carer on ee cep Meshes NEED ey 42, 000 International Catalogue of Scientific Literature______________________ 7, 500 ASEFODDYSiGAlT ODSERV a tomy sae: Sw: Tp a po ee ee 13, 000 National Museum: gn tune ama ad GROG a ee Pal ale 20, 000 BeBe ea Gira 4 vermabee M0 a a ee a ee 69, 715 Preservationvio£ ‘collections... 2022) 0s. ee 300, 000 BUGIN eg KEG AITS ts eee EE EL OE ot ee eee ee ee 10, 000 TOOK S Betis eae Bree EPR 5 ERS ps Sue ee ea So ee ee oe 2, 000 MOstaee: 7 ae eh le ee hee le ee eS ee 500 Heating -equipment,.Aircraft ‘Building 2 os) So. aerhee eer Te 14, 000 National, Zoological Parke. =— es tes ep eee ee 115, 000 Increase of compensation (indefinite) ____-___________ ron Nee ue O ear ie up ree ehcL F Rotall ta fug tol Pes tn epee tart e pare eee ee oat eee Ee 638, 715 In addition to the above there was included under the general ap- propriation for printing and binding an allotment of $76,200 to cover the cost of printing and binding the Smithsonian annual report and reports and miscellaneous printing for the Government branches of the Institution. RESEARCHES AND EXPLORATIONS. Every year the Institution sends out or participates in, so far as its limited means will permit, expeditions for the purpose of increas- ing scientific knowledge in various parts of the world which have been previously but imperfectly known to science. In former years every continent and nearly every country on the globe has been vis- ited by Smithsonian scientific explorers, and the result has been the accumulation of a valuable mass of information on the people, fauna, flora, geology, geography, ethnology, etc., of the various regions visited. Many of the more important results of these expeditions have been published by the Institution, and thereby have the chief objects of the Smithsonian as laid down by its founder, “the increase and diffusion of knowledge among men,” been carried out. While the prevailing universal high costs have considerably re- duced the effectiveness of the Institution’s funds for research and exploration, nevertheless several expeditions were in the field during the past year, and the activities of some of these are here briefly described. REPORT OF THE SECRETARY 19 GEOLOGICAL EXPLORATION IN THE CANADIAN ROCKIES. Geological field work in the Canadian Rocky Mountains was con- tinued by your secretary during the field season of 1919, with the following objects in view: (1) The discovery of an unmetamor- phosed, undisturbed section of the Upper Cambrian formations north of the Canadian Pacific Railway; and (2) the collection of fossils to determine the various formations and to correlate them with the Upper Cambrian formations elsewhere. The region selected for examination was the area about Glacier Lake, which was reached through Bow Pass, down the Mistaya Creek to the Saskatchewan River, and thence up to the headwaters of the Middle Fork. The geological section measured is of such interest that I will de- scribe it briefly. The rocks exposed in the highest cliffs of Mount Forbes and Mons Peak belong to the great Carboniferous system of rocks of this region. Below this series is a belt 1,000 feet or more in thickness comprising the Devonian rocks, beneath which are the strata of the Sarbach formation of the Ordovician system. Under these again are the five formations of the Upper Cambrian series, and at one place near Mount Murchison is a low ridge formed of strata of Middle Cambrian age. Special attention was given to the glaciers of which there are many fine examples in the region. Beautiful photographs of some of these were obtained, one showing a complete glacier from its névé to its foot. A preliminary examination of the fossils in the formations studied correlates them with the Upper Cambrian formations of Wisconsin and Minnesota and the Upper Cambrian section in south- ern Idaho, and to a lesser extent with that of the central belt of Pennsylvania. PALEONTOLOGICAL FIELD WORK. Two short field trips were taken during the year by Dr. R. S. Bass- ler, curator of paleontology, for the purpose of securing certain specimens of fossils and rocks required for the Museum exhibition series. During the previous year some excellent exhibition specimens had been located in southeastern Indiana, but owing to the impos- _ sibilty of securing help to get them to a freight station, it had been necessary to leave them. This year, conditions being the same, they were carefully wrapped in burlap and padded with a quantity of weeds and laboriously dragged along the rails to the nearest station. The same method was used in transporting to a station the specimens found this year along a creek in the same locality, where heavy spring freshets had uncovered some richly fossiliferous layers of rock. One of these specimens, a slab several feet in length and width, was crowded with impressions of the branching fossil seaweed Burtho- trephis, and with excellent examples of the dumb-bell seaweed Ar- 20 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. thraria. A specimen showing an assemblage of these ancient plant remains had long been needed in the fossil-plant exhibition series in the Museum. { Later in the year, Dr. Bassler proceeded to Dayton, Ohio, to pre- pare for shipment to. Washington the largest entire American tri- lobite so far discovered. The trilobite was uncovered by the pick of a workman in the excavations for the Huffman conservancy dam, 6 miles east of Dayton. Mr. Arthur E. Morgan, chief engineer of the Miami conservancy district, recognized the scientific value of the fossil animal and presented it to the Institution, where it now forms a most unique and instructive exhibit in the hall of invertebrate paleontology of the National Museum. The specimen is of special value since it has become the type of a new species, /sotelus brachyce- phalus, described by Dr. August F. Foerste, of Dayton, Ohio. THE COLLINS-GARNER FRENCH CONGO EXPEDITION. The “ Collins-Garner expedition in the interests of the Smithsonian Institution,” which had been ‘collecting biological material in the Trench Congo since the summer of 1918, returned to this country early in 1919, but the collections resulting from the expedition were incorporated into the Museum series of African material during the past fiscal year. Mr. C. R. W. Aschemeier, who represented. the Institution, collected and turned over to the Museum some 2,500 mammals, birds, reptiles, fishes, and invertebrates, an invaluable addition to the Museum collections. THE SMITHSONIAN AFRICAN EXPEDITION, Last year it was announced that an expedition to Africa had been organized to collect plants and animals needed by the Museum to sup- plement the magnificent collections made on that continent by Col. Theodore Roosevelt and other explorers. This expedition, under the title of the “ Smithsonian African expedition, under the direction of Edmund Heller in conjunction with the Universal Film Manufac- turing Co.” sailed on July 16 on the steamship City of Benares, arriving in Cape Town August 13. Besides Mr. Heller, the Institu- tion was represented by Mr. H. C. Raven, who has in former years made collections for the Smithsonian in Borneo, Celebes, and other regions. In the vicinity of Cape Town, Mr. Raven was able to collect only insects and invertebrates, and from there he went to the Addo Bush, where 19 days were spent in collecting small mammals and birds. Going through Durban and Johannesburg, Mr. Raven spent two weeks collecting at Ottoshoop in the Transvaal, after which he pro- ceeded to Victoria Falls, and from there he and Doctor Shantz, who REPORT OF THE SECRETARY. at was representing the United States Department of Agriculture, left for the Kafue River region, where they camped for several weeks. After spending some weeks along the Congo, they reached Lake Tanganyika, where camp was made for about a month. The next’ stop of any length was in Uganda, where a few days over a month was spent in collecting in the Bundogo Forest. As the whole forest was in the sleeping-sickness area, it was necessary to get a special permit from the district commissioner to enter it, and the native boys engaged by Mr. Raven had to be examined by a doctor before entering the area and again on leaving it. At the close of the year, Mr. Raven was at Masindi, in Uganda, preparing to return to the United States. Only one shipment of material had been received by the end of the year, consisting of 239 mammals and birds from southern Africa, which, with the remainder of the specimens still to be received from Mr. Raven, will be of great value in working up the African material already in the Museum collections. AUSTRALIAN EXPEDITION. Through the continued generosity of Dr. W. L. Abbott, the Insti- tution sent Mr. Charles M. Hoy to Australia for the purpose of col- lecting vertebrates, especially those which are in danger of extermina- tion. As the Museum at present contains only about 200 specimens of the remarkable Australian mammal fauna, this expedition is of the utmost scientific importance, especially since in the future it will be impossible to secure an adequate representation of the fauna owing to their rapid extermination. Mr. Hoy began work in Australia about the 1st of June, 1919, and by the close of the past fiscal year one shipment had been received at the Museum, consisting of 240 mammals and 228 birds. The follow- ing passages from reports and letters received from Mr. Hoy give an idea of the conditions under which the collecting was carried on: Nine weeks were spent in the Wandandian region (19 miles southwest of Norwra, New South Wales), with the result of but 181 mammals and 124 birds collected. Among the mammals 10 genera and 12 species are represented in my collection. The greatest agent working toward the extermination of the native animals is the fox ; next comes the cattle and sheep men, who distribute poison by the cart- load in the effort to reduce the rabbits. This has also caused or helped to cause the extermination of some of the ground-inhabiting birds. Another great agent is the bush fires which sweep over the country. These are often lit in- tentionally in order to clear out the undergrowth and thus increase the grass. The extermination of the native mammals has apparently gone much further than is generally thought. Many species that were plentiful only a few years ago are now almost, if not altogether, extinct. Diseases have also played a great part in the extermination. The native bear died in thousands from a dis- ease which produced a great bony growth on their heads. A mysterious disease 22 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. also spread through the ranks of the native cat, Dasyurus viverrinus; the domestic cat also played a great part in their extermination. Even adult speci- mens of Dasyurus were often dragged in by the family eat. It is the killing and burning of the brush by the cattlemen that does the most to kill off the animals, and they are yearly reaching farther and farther away from the railroads. One thing that was very noticeable was the great abun- dance of the introduced rats. They seem to have driven out or killed off prac- tically all the native rats, and I found them everywhere. ANTHROPOLOGICAL RESEARCHES IN THE FAR EAST. Dr. AleS Hrdlitka, curator of physical anthropology, National Museum, made an extended trip to the Far East in the interest of his researches on the origin of the American Indian and the peopling of eastern Asia. While in China he assisted with the organization of anthropological research in connection with the Peking Union Medical College in China. During this trip, which occupied over five months, Doctor Hrdlitka visited Japan, Korea, Manchuria, northern China, and the border of southern Mongolia, examining the local collections as well as the actual populations. The results of the journey have contributed very materially to the solution of the problems for which the trip was made, in addition to which it was possible to arrange for ex- changes of material, and especially to organize a nucleus for an- thropological investigation in China. Doctor Hrdli¢ka returned by way of Hawaii, where a two weeks’ stop was made for the study of the natives and of Hawaiian problems in general. While at Peking Doctor Hrdlitka consulted prominent foreigners, as well as Chinese scholars, on the advisability of establishing in Peking, or of taking steps toward the establishment there of a “China Museum of Natural History,” which, like the United States National Museum, would include the departments of geology, biol- ogy, and anthropology, and which would serve as a center for inves- tigators in these lines in China and the Far East. Before his de- parture the opportunity was given him by representatives of several of the ministries and other officials to make the proposal more for- mally, with the result that a committee was to be organized for con- sideration of the project. BOTANICAL EXPLORATION IN HAITI. Through the generosity of Dr. W. L. Abbott, for many years a benefactor of the Institution, it was possible to detail Mr. Emery C. Leonard, aid in the Division of Plants, United States National Museum, as botanical collector to accompany Doctor Abbott to Haiti upon his last visit of exploration in that country, from February to tse REPORT OF THE SECRETARY. 23 July, 1920. A collection aggregating 10,000 specimens, representing about 2,700 collection numbers, was secured by Mr. Leonard in sey- eral characteristic regions. This material will prove of exceptional value and interest from the fact that, little botanical collecting hay- ing been done in Haiti, the flora is in consequence very imperfectly known. The field work may be summarized as follows: After completing their outfit at Port au Prince, the point of arrival, Dr. Abbott and Mr. Leonard proceeded by railroad to St. Marc, thence by native fishing schooner to Gonave Island, lying a short distance off the coast. This island, which is about 30 miles long from east to west and 10 miles broad, is entirely of coral formation, which decomposes to form a very rich reddish soil. Work was carried on principally upon the northern side. A low mountain range forms the backbone of the island, intersected by occasional sharp ravines, in which are found a very few springs. The coast is bordered by an almost un- broken fringe of mangroves, back of which is a belt of bare saline flats. Next in succession is a region of low arid foothills, from which the mountains rise rather abruptly. The hills and slopes are covered with thorny thickets, chiefly of leguminous shrubs and low trees, with cacti interspersed, but the uplands (called La Table) open in large grassy areas, with only scattered trees and shrubs, which afford rich pasture. About three weeks were spent on the north side of the island, working from Anse Galette and Etroite, and somewhat later a week on the south shore, with the small village of Pickney as base. The second part of the exploration covered the region west and south of Lake Saumatre. Access was easily gained by railroad from Port au Prince to Etang, on the west shore of the lake. After a week’s collecting in the vicinity of Etang the party traveled by boat to Fond Parisien, on the southeast shore, and, procuring donkeys, proceeded overland to Mission, in the midst of the La Salle Mountains, where an altitude of 2,000 meters was reached. From this elevation down to 900 meters the slopes were sparsely covered with pines, and, where protected from fire, with dense thickets that sheltered a luxuriant growth of ferns. About two weeks were spent in collecting in this region. The final portion of the field work was carried on in the region of Furcy, which lies a short distance south of Port au Prince. The collections here were made mostly on the wooded ridge east of Furcy on the trail to Grande Touraine. The region is well watered and has a delightful climate, but the country about Furcy itself has been almost entirely cleared of forests. Of the plants collected perhaps one-third are ferns, the remaining portion con- sisting of shrubs and herbaceous plants, among which are a considerable number of grasses and cacti. The cacti appear to be of special interest. BOTANICAL EXPEDITION TO BRITISH GUIANA. Through the cooperation of the United States Department of Agri- culture, the Gray Herbarium of Harvard University, and the New York Botanical Garden, a trip to British Guiana was made by Dr. A.S. Hitchcock, custodian of the section of grasses, National Museum, Doctor Hitchcock reports: I left New York October 4 and arrived at Georgetown, British Guiana, October 22, visiting on the way down the islands of St. Thomas, St. Croix, St. Kitts, Antigua, Guadeloupe, Dominica, Martinique, St. Lucia, and Barbados. On the return trip in February the islands of Trinidad and Grenada were visited. Col- 24 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. lections of grasses were made on all the islands. In British Guiana a general collection of flowering plants was made, a set going to each of the contributing institutions. My headquarters were at Georgetown, the capital and only large city of the colony. Here there is a good botanical garden and a herbarium of British Guiana plants, known as the Jenman Herbarium. Prof. J. B. Harrison, the director of science and agriculture, is in charge of the scientific activities of the colony and rendered me very efficient aid. The greater part of British Guiana is covered with virgin forest. The vast savannas of Venezuela extend into the southern part of the colony. The tempera- ture is high, 75° to 85°, according to the season, and the rainfall at Georgetown is about 90 inches. The settlements are mainly along the coast, and travel in the interior is by boat along the numerous rivers. The country for some dis- tance back of the coast is low and wet. The chief industry is the raising of sugar cane. The health of the colony is fairly good, though there is much malaria. The botanical results were very satisfactory. About 1,200 numbers of plants were collected. Especial attention was given to the grasses, of which 171 species are now known to grow in the colony, BOTANICAL EXPLORATION IN GLACIER NATIONAL PARK, MONT. Mr. Paul C. Standley, assistant curator in the Division of Plants, United States National Museum, spent about 10 weeks, from July to September, 1919, in Glacier National Park, Mont., under the au- thority of the National Park Service, for the purpose of studying the vegetation of the region. A large series of photographs and about 4,000 specimens, representing over 900 species of plants, were ob- tained, which will serve as the basis of a popular illustrated account of the plants to be published by the Park Service, and a more com- plete technical paper on the flora, in process of publication by the National Museum. ‘The zonal distribution of the plants, which is of extreme interest, is discussed briefly by Mr. Standley, as follows: The Continental Divide, which traverses the park, has a marked influence upon plant distribution. On the east slope, whose drainage is partly into the Missouri River and partly into Hudson Bay, the flora is of the Rocky Mountain type, like that of Wyoming and Colorado; while on the west slope, whose streams drain into the Columbia River, the flora is more obviously related to that of the Pacific coast. The forests about Lake McDonald are very dense and are composed of unusually large trees. Although not nearly so extensive, they are much like those of the humid regions of Oregon and Washington. In the vegetation there are represented four of the life zones recognized by biologists. The transition zone is indicated on the west slope by small areas of yellow-pine timber, and east of the park are the prairies of the Blackfoot Indian Reservation, which extend also within the park boundaries along the stream valleys. The plants here are chiefly herbs, with a few shrubs, and they belong mostly to species which have a wide distribution over the Great Plains. By far the largest portion of the park is covered with the characteristic vegeta- tion of the Canadian zone, which is the heavily forested area. Above the Canadian zone, around timber line (6,000 to 7,500 feet), lies a narrow belt belonging to the Hudsonian zone. The trees here are mostly low and stunted, REPORT OF THE SECRETARY. 95 and their branches frequently lie prostrate upon the ground. Above this belt, and occupying the highest exposed slopes, lies the Arctic-Alpine zone, whose vegetation is composed chiefly of small herbaceous plants, with a few dwarfed shrubs, mostly willows. Many of the species of this zone are widely distributed in alpine or arctie regions of North America, and some of them occur also in similar situations in Europe and Asia. BOTANICAL EXPLORATION IN JAMAICA. Mr. William R. Maxon, associate curator in the Division of Plants, United States National Museum, accompanied by Mr. E. P. Killip, aid, was detailed to field work in Jamaica in February last for the purpose of making botanical collections in general and of securing fern material for use in connection with a projected volume upon the ferns of Jamaica. Over two months were spent in the island, in- cluding a pericd of three weeks in the Blue Mountain region, with the Cinchona Botanical Station as base. Other regions covered in- clude Mount Diablo, Montego Bay, Mill Bank, and Seamens Valley, and the southern border of the peculiar “cockpit country ” above Ipswich, a wooded area of limestone “sinks.” Upward of 10,000 specimens were collected, representing about 1,700 collection num- bers. In addition to the series to be retained by the National Museum, nearly uniform sets of the ferns and flowering plants have been distributed to the Gray Herbarium of Harvard University, the New York Botanical Garden, the Field Museum of Natural History, and the University of Illinois, all of which contributed equally to the field expenses of the work. Sets of the woody plants and orchids have been sent also to the Arnold Arboretum of Harvard University, and to Mr. Oakes Ames, respectively, in return for similar assistance. The lower cryptogams of the collection are in process of identifica- tion and wil be distributed shortly. EXPLORATIONS IN SANTO DOMINGO. During the first three months of the fiscal year Dr. W. L. Abbott continued his scientific investigations in Santo Domingo, stopping at Sosua, on the north side of the island, where a search was made for certain birds needed to fill gaps in the series already collected. The Samana Peninsula was then explored, after which Dr. Abbott visited the islets of Saona and Catalina, off the southeastern corner of Santo Domingo, and concluded his investigations with a few days’ ~ work at Lake Enriquillo. The material collected on this trip and the previous trip ending just before the beginning of the fiscal year was varied in character, embracing the several groups of vertebrates as well as mollusks, in- sects, and plants, with a plentiful series of archeological objects from caves in the Samana district. Of birds alone, 278 study skins, 87 296 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. alcoholics and skeletons, and 56 eggs were collected, including birds representing four species not hitherto possessed by the Museum and three or four other species not previously known to occur on the island. LECTURES. Hamilton fund lecture-—The Hamilton fund was placed under the administration of the Institution by the Rev. James Hamilton in 1875, the interest to be used for “ lectures on scientific or useful sub- jects.” Under the auspices of this fund an interesting lecture was delivered on April 13 in the auditorium of the National Museum by the Rev. Charles E. Jefferson, D. D., on “The old order and the new,” in which Dr. Jefferson gave his views as to the causes which led the world into its present unsettled condition and of the solution of the problems presented. Lectures for the Y. M. C, A—At the request of Dr. W. C. Little, field secretary of the Young Men’s Christian Association, a series of lectures on scientific subjects written in a style to be instructive and entertaining to a general audience was prepared by members of the staffs of the Institution and its branches, for use in the educational extension work of the association. The scheme was to have these lectures delivered in rotation by volunteer lecturers in many different localities in the United States, thereby reaching a large number of people interested in keeping in touch with the advance of science and progress in general. The lectures prepared by members of the Smithsonian staff were as follows: The Sun, by C. G. Abbot. Cave Dwellings of the New and Old Worlds, by J. W. Fewkes. The Primeval Life of North America, by R. 8. Bassler. A Visit to the Races of Man, by Walter Hough. Tn the Land of the Great Natural Bridges, by Neil M. Judd. The Progress in Land Transportation, by Carl W. Mitman. Antiquities of the Bible, by I. M. Casanowicz. Strange Facts in Nature, by Austin H. Clark. Flying Animals, by Austin H. Clark. Interesting Animals and Birds from East Africa, by Austin H. Clark. Extinct Monsters of North America, by Charles W. Gilmore. Mammals of Ancient North America, by James W. Gidley. CINCHONA BOTANICAL STATION, In my report last year it was stated that negotiations had been begun with the Government of Jamaica to renew the Smithsonian’s three-year lease on the Cinchona Botanical Station which was can- celed during the period of the war. This was successfully arranged in January, 1920, and the renewed lease dated from January 1. The station is maintained by the subscription of a number of insti- tutions in this country for the purpose of enabling accredited inves- REPORT OF THE SECRETARY. 27 tigators to study the rich and interesting flora of the region. From January 1 to the close of the year the following botanists planned to avail themselves of the privileges of the station: Messrs. W. R. Maxon and E. P. Killip, of the United States National Herbarium, for work on the taxonomy of ferns and flowering plants; Mr. Fred- erick Boughton, of Pittsford, N. Y., for collecting fungi; Dr. J. M. Thompson, of Glasgow, for work on the ferns; and Prof. R. E. Danforth, of Rutgers College, also for work on the ferns. EXHIBITION OF SOUTH AMERICAN HISTORICAL DOCUMENTS. From July 28 to August 9, 1919, there was held in the Smithsonian Building an exhibition of South American historical documents brought together by Sefior Don Jorge M. Corbacho, a member of the Peruvian Parliament and delegate to the Pan American Congress. The collection, containing official documents signed by the Spanish conquistadores, the viceroys at Lima and the revolutionary leaders during the wars for independence, was one of inestimable value and was shown at the Smithsonian for the first time in North America. RESEARCH IN TROPICAL AMERICA. In June 1920, the National Research Council, of which your secretary is a vice chairman, held a conference on the project of incor- porating an institute for promoting research in tropical America, including exploration and the establishing of laboratories and re- search stations, and of effecting cooperation between the institutions interested in tropical research and exploration. The membership of the proposed institute was to consist of representatives (one each) from institutions interested in such research, and these institutions were invited by the Research Council to appoint representatives, but at the close of the year replies had not been received. PUBLICATIONS. The Institution and its branches issued during the year 95 volumes and separate pamphlets. Of these various publications there were distributed a total of 143,290 copies, which includes 157 volumes and separates of Smithsonian Contributions to Knowledge, 24,949 vol- umes and separates of Smithsonian Miscellaneous Collections, 16,720 volumes and separates of Smithsonian Annual Reports, 81,936 vol- umes and separates of the various series of the National Museum, 16,761 publications of the Bureau of American Ethnology, 1,958 special publications, 19 volumes of the Annals of the Astrophysical Observatory, 23 reports on the Harriman Alaska expedition, and 564 reports of the American Historical Association. 28 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. Through its publications the Institution carries out one of its principal objects, the “diffusion of knowledge.” The Smithsonian series, except the annual report, are printed from Smithsonian funds in small editions for distribution principally to libraries and scien- tific and educational establishments throughout the world. The annual report, containing a general appendix consisting of a num- ber of articles illustrating recent advances in nearly every branch of science, is printed by congressional appropriation in editions of 10,000 copies and is in great demand throughout the country. The Museum and Bureau of Ethnology publications are discussed in detail in the reports of those branches appended to this report. Of the Smithsonian Miscellaneous Collections, 14 numbers were issued, among which may be mentioned 2 papers by your secretary on his researches in Cambrian geology and paleontology, a paper showing the relations between the variations in solar radiation and in the weather, based on the work of the Smithsonian Astrophysical Observatory on the solar constant of radiation, and a fourth revised edition of the Smithsonian Meteorological Tables, for which there is a continued demand. Allotments for printing.—The congressional allotments for the printing of the Smithsonian report and the various publications of the branches of the Institution were practically used up at the close of the year. The allotments for the coming year ending June 30, 1921, are as follows: For the Smithsonian Institution: For printing and binding the annual reports of the Board of Regents, with general appendices, the editions of which shall not exceed 10,000 copies______________ $10, 000. 00 (Provided, That the unexpended balance of the appropriation of $10,000 made for this purpose in the sundry civil act approved . July 1, 1918, is hereby reappropriated and made available during Che tiSeal “Var OA!) es een ee SS I Ea en ea 5, 220. 99 For the annual reports of the National Museum, with general appen- dices, and for printing labels and blanks and for the bulletins and proceedings of the National Museum, the editions of which shall not exceed 4,000 copies, and binding in half morocco or ma- terial not more expensive, scientific books and pamphlets presented to or acquired by the National Museum library__~_-__~__-___--__ 37, 500. 00 For the annual reports and bulletins of the Bureau of American Hth- nology and for miscellaneous printing and binding for the bureau_ 21, 000. 00 For miscellaneous printing and binding: International bx Chaneess= eat: a ee) eek ae 200. 00 International Catalogue of Scientific Literature________________ 100. 00 Nationa Zoolorvical Park: 533235) CAs O67 es Se See ee 200. 00 Astrophysical ‘Observatory. Tuer ees aie ea RO Las 200. 00 For the annual report of the American Historical Association______ 7, 000. 00 COMMITTEE ON PRINTING AND PUBLICATION, The function of the Smithsonian advisory committee on printing and publication is to consider all manuscripts offered for publication REPORT OF THE SECRETARY. 29 by the Institution or its branches. During the year 10 meetings were held and 93 manuscripts were passed upon. The membership of the committee is as follows: Dr. Leonhard Stejneger, head curator of biology, National Museum, chairman; Dr. George P. Merrill, head curator of geology, National Museum; Dr. J. Walter Fewkes, chief, Bureau of American Ethnology; Mr. N. Hollister, superintendent, National Zoological Park; and Mr. W. P. True, editor of the Smith- sonian Institution, secretary. LIBRARY. The Smithsonian library received during the year 6,995 volumes and pamphlets, distributed as follows: To the Smithsonian deposit in the library of Congress, 4,019; to the Smithsonian office, Astro- physical Observatory, and National Zoological Park libraries, 428; and to the National Museum library, 2,548. Continued use of the library’s collection of works on aeronautics has been made by students of aeronautics, both of the United States and of foreign countries. Forty titles were added to the collection during the year. In the De Peyster collection, author cards have been made for the Napoleon series and for the works on British, Ger- man, and Jtalian history. The work of the library has suffered from the fact that the appro- priation for binding has not kept pace with the greatly increased cost. This has reduced the number of books bound during the year to 737, as compared with 1,322 in 1919 and 1,706 in 1918. NATIONAL MUSEUM. The congressional appropriation for the maintenance of the Museum has remained practically the same for many years, and as a result of the great increase, both in size and importance, of the collections, not only has it been impossible to undertake desirable new lines of work, but also existing work has been greatly hampered by the necessity of observing the strictest economy. The two most serious handicaps to the Museum in extending its usefulness to the people of the country are lack of space for proper exhibition of its valuable collections and an insufficient staff of expert curators. This last has in several cases necessitated grouping wholly unlike divi- sions under one curator, with the result that the sections in which there is no specialist in charge must remain practically at a stand- still. In June, 1920, a small congressional appropriation made possible the establishment of the National Gallery of Art as an independent bureau under the administration of the Smithsonian Institution, in- stead of being as previously a part of the Museum, the change to take - effect on July 1, 1920. Mr. W. H. Holmes, head curator of the 80 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. department of anthropology in the Museum, will become director of the National Gallery at the beginning of the year. The Freer Gallery of Art was brought nearly to completion dur- ing the year, and arrangements were made with the Office of Public Buildings and Grounds for the construction of driveways and the improvement of the grounds around the building. The collections have begun to come in from the executors of Mr. Freer’s estate and are being stored in the building until the installation can be begun. During the past year the Museum acquired a total of 216,871 speci- mens, classified as follows: Anthropology, 15,254; zoology, 101,554; botany, 35,211; geology and mineralogy, 22,400; paleontology, 40,000 ; division of textiles, 1,716; mineral technology, 627; mechanical tech- nology, 97; and National Gallery of Art, 12. Four hundred and ninety-five lots of material were sent to the Museum for examination and report by members of the staff, and 4,306 duplicate specimens were distributed for educational purposes. The great mass of material for the Museum’s collection of objects relating to the World War filled the space allotted to it in the Arts and Industries Building and overflowed into the Natural History Building and the Aircraft Building. This great collection, made pos- sible through the hearty cooperation of the War and Navy Depart- ments, contains material relating to practically every phase of the war, both on land and sea. The Navy furnished much interesting material relating to submarine warfare and other naval activities during the war, and the War Department assembled and deposited in the Museum exhibits illustrating military operations in every branch of the service, including the Air Service, Ordnance, Chemical War- fare, Quartermaster, Engineer, Medical, and Signal Corps. A full account of this valuable and instructive collection is given in the re- port of the administrative assistant in charge of the Museum, in an appendix to this report. Additions to the collections in the division of history include 226 complete uniforms of the types worn in the United States Army from 1776 to 1909; miscellaneous scientific apparatus used by Joseph Henry (1799-1878) during the latter part of his life, the gift of his daughter, Miss Caroline Henry; watches owned by Maj. Gen. George B. McClellan, United States Army; swords and other military relics of Maj. Gen. John R. Brooke, United States Army; and many other objects of historical interest and value. In anthropology the most noteworthy accessions were some valu- able ethnological material collected during the period of military oc- cupancy of the Philippines; collections made by members of the staff of the Bureau of American Ethnology, and transferred to the Mu- seum; and a collection of nearly a hundred objects of Christian and Buddhist religious art in wood, copper, bronze, and silver. REPORT OF THE SECRETARY. or The department of biology showed very gratifying results both in number of specimens and in the scientific importance of the material received. Through the liberality of Mr. B. H. Swales, no less than 163 species of birds new to the Museum’s collections were among the year’s accessions and, with the continued assistance of Dr. W. L. Ab- bott, 240 mammals and 228 birds from Australia were received as a first installment of a collection being made there by Mr. Charles M. Hoy. LING caring) er ee. Lei 1, 854 Deduct loss (by exchange, death, and return of animals on deposit). -.--.......---..-------+---+---+- 427 Almalsaninand June s0;L9202 2 os ete aaa ts een ccen tine att ecekhl dette see 1,427 Class. Species. |Individuals. UPAIDTTLE I Go eT TRE ee Senne mete Ss eer ers: + rete e oa oe 166 496 DADE Soe hase pie See ie A pie laa aa gt a alee aa Ee aah 1 pap ea heal 225 847 Meanislesee. eek o. SUEE ELE US... oSee ees. Seta se eek eae Serf Shock 28 84 SEITE ER AC eon ek. iain on cps obicis an ialp sisisinls sine ate aie wn eeisnle one ernie te acts 419 1,427 It will be interesting at this time to submit figures showing the comparative size of the collection at the close of each fiscal year since the foundation of the park. The years and numbers of animals are as follows: Peet) od. .o isdui sour {lin s peo agg7eu2tesogy 110 10 WOT 1, 193 itnre rye wri cai dor ta An Bolt |.49081_0: beer 2oune Jayit ott) 1, 402 eal A aaa ae eee 51O 1900renad tice ath paged Gal 1, 416 7 JE SN og oa PR ALI Rl gota Mera de, 1, 424 emai eT ee Baa SOLU etek WEN SOE ae ee! SRL se2TN UPS RP age ge Cb Rima gia Care Me asn aie OL ook. ibe 1, 551 mT OD. Wie osatt 1074 10 FAG? | Mg Fh). WOE OF 1b. . JSON ABE 1, 468 Maerake aldioliniinos ban . 615 ota i Mw. oli ieer. Yuees 1, 362 eee 9 890))|,19151. eo ads i eranoy ys 1, 897 a leg eT iat is ae NiO iB (out 1, 383 be velar aaa Cage SE gh BC N joke! MPA Ne AN CE ASME) 1, 223 meme eeseprtc! A Celts ne Mt £OGO | 191s res Web se 1, 247 MAO 2 DOS. Oe oO) 1 AGE 19 PZT) ALISON WOKE 9 1, 336 1905... ind. by Joba conssom4mpedio Suvi all .soodad & 1, 427 Bete: al econls nin el fy: 1, 272 The number of animals is now 124 under that of the record year (1912), but is greater than has been maintained since 1918. The monetary and scientific value of the collection is, however, very much greater than ever before. VISITORS. The attendance for the fiscal year, as determined by count and estimate, was 2,229,605, a daily average of 6,108. This is the first time that the official records have gone above 2,000,000. The greatest number of visitors in any one month was 402,403, in April, 1920, an average per day of 13,413. The largest single day’s attend- ance in the history of the park occurred in this month, on Sunday, the 11th, when 95,000 people were admitted to the gates. The other 42803 ° —22-—_7 98 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. three Sundays in April show attendance records of 25,000, 87,000, and 55,000. The attendance by months was as follows: In 1919: July, 125,700; August, 230,255; September, 268,941; October, 205,398; November, 204,944; December, 74,161. In 1920: January, 55,547; February, 27, 099; March, 203,803; April, 402,403; May, 265,604; June 165,750. Ninety-six schools and classes visited the park during the year, with a total of 8,959 individuals. As usual, these came largely from the District of Columbia, Maryland, and Virginia; but several were from States as distant as Pennsylvania and Massachusetts. IMPROVEMENTS. The most needed improvement completed during the year is the’ ‘public-comfort station at the Harvard Street entrance. This build- ing is set into the steep hillside just inside the gate, and is so nearly hidden by the natural growth of trees, especially by the low-sweeping branches of some fine beeches, that comparatively little planting was necessary to improve the ground around it. The row of old wooden cages, along the hill just north of the bird house, the first cages used in the park, some of which were originally brought from the Smithsonian grounds when the park was first occupied, were replaced by nine new inclosures for strictly outdoor animals, especially for the medium-sized carnivores not requiring artificial heat. The new cages are made of iron framework, covered with heavy mesh wire, with cement floors, and comfortable, sanitary retiring rooms in the rear. The largest of these new cages, 20 by 20 by 12 feet in size, is now occupied by the Mexican pumas. The other eight, from 10 by 16 by 9 feet to 14 by 16 by 10 feet in size, are used for the snow leopard, lynxes, certain of the Canide, and a large chacma baboon. The type of construction adopted for these cages has proved exceedingly satisfactory, and the airy, cleanly quarters are much admired by the visitors. The quarters occupied by the chimpanzee in summer having proved unsatisfactory since this animal became mature, it was de- cided to prepare outdoor cages for his use adjoining his winter home in the lion house. The hyena cage next to his indoor quarters was therefore remodeled and connected with his main apartment, and two spacious outdoor yards prepared for his use. He now has two com- fortable indoor rooms and two outdoor yards, which makes the problem of his care much more simple, as it is not necessary with the new arrangement for his keepers to work while he is in the same room or outdoor cage. Among minor improvements completed during the year are wide concrete steps connecting the walk in front of the bears with the walk on the lower level along the sea-lion and beaver pools; new REPORT OF THE SECRETARY. 99 drainage gutters at antelope house; new fence along hilitop below children’s playground and sand boxes near the Adams Mill en- trance; and repairs to road between Klingle entrance and the upper ford. The reconstruction of the old outdoor chimpanzee cage into quarters suitable for a grizzly bear and the re-covering of the large outdoor cage for the California condors were both well under way, and would have been completed before the close of the fiscal year but for the fact that the cement and wire needed in the work could not, at that time, be obtained in Washington. Alteration of the western boundary.—This item has been consid- ered in the annual report for many years, and it is therefore espe- cially gratifying now to be able to report actual progress on the purchase of the land necessary to protect the western entrance. The sundry civil act for 1921, approved during the past year, carries an appropriation of $80,000 for the purchase of all the land between the western boundary of the park and the unnamed street connecting Cathedral Avenue with Klingle Road, excepting one small lot at the southern end, together with 300 feet each side of Jewett Street front- ing on Connecticut Avenue. All of Jewett Street, which now con- nects the park with Connecticut Avenue, and the included portion of the unnamed street running parallel with Connecticut Avenue are to become a part of the National Zoological Park, and a 50-foot roadway at each end of the area to be purchased will be taken over by the District of Columbia to connect the unnamed street with Con- necticut Avenue. The area appropriated for includes 209,050.5 square feet, and the park will now be bounded at this point by public highways instead of privately owned property. The frontage on Connecticut Avenue, including the former Jewett Street, will be 625 feet—ample for all purposes. IMPORTANT NEEDS. Restaurant.—As mentioned in the last annual report one of the most urgent needs of the park is a suitable public restaurant. The present refreshment stand, entirely inadequate and in a bad state of repair, is unsuited to the present-day crowds of visitors. It is be- lieved that an up-to-date building on the present site, 50 by 100 feet in size, and of two floors, one opening onto the lower slope to the west, would meet the requirements and would pay the Government a fair income in rent. Preliminary plans for such a building have been made by the office of the municipal architect; the present estimated cost of construction is $65,400. Alteration of the southeastern boundary.—The District government has now opened Adams Mill Road from the southeastern entrance of the National Zoological Park to Harvard Street and a narrow strip 100 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920, of land, between the park and this new roadway, between Clydesdale Place and Ontario Road, still in private ownership, should become Government property. This narrow strip of land is of very little use, except possibly for garages, and its close proximity to the en- trance to the park makes its public ownership of great importance. The amount required for its purchase is comparatively small and its acquisition by the park or by the District of Columbia should not long be delayed. The cost should not exceed $4,000. Outdoor quarters for mammals—Provision should be made for the exhibition of lions, Siberian tigers, and other mammals now occupy- ing quarters in certain buildings, in outdoor inclosures with warm but unheated shelters. The animals themselves would be greatly im- proved by such conditions and the space they now occupy in buildings would become available for animals actually requiring heated quar- ters in winter. It is proposed that, when funds may be obtained for the purpose, large inclosures of this type be constructed on the space between the lion house and the monkey house now utilized as a pad- dock for ostriches. The most urgent need of the park at the present time is increased compensation for certain of the employees, particularly the keepers and policemen. While the rate of pay for these and other employees has been slightly increased during the past four years, the increase has in no measure kept pace with the cost of living, and it is becoming more difficult all the time to retain valuable and trained men in the service. Respectfully submitted. N. Houuister, Superintendent. Dr. Cuartes D. Watcorr, Secretary, Smithsonian Institution, Washington, D.C. APPENDIX 5. REPORT ON THE ASTROPHYSICAL OBSERVATORY. Sir: The Astrophysical Observatory was conducted under the fol- lowing passage of the sundry civil act approved July 19, 1919: Astrophysical Observatory: For maintenance of Astrophysical Observatory, under the direction of the Smithsonian Institution, including assistants, pur- chase of necessary books and periodicals, apparatus, making necessary obser- vations in high altitudes, repairs and alterations of buildings, and miscella- neous expenses, $13,000. The observatory occupies a number of frame structures within an inclosure of about 16,000 square feet south of the Smithsonian ad- ministration building at Washington, and also a cement observing station and frame cottage for observers on a plot of 10,000 square feet leased from the Carnegie Solar Observatory, on Mount Wilson, Calif. The present value of the buildings and equipment is estimated at $50,000. This estimate contemplates the cost required to replace the outfit for the purpose of the investigation. WORK OF THE YEAR. At Washington—Much labor was expended on the preparation of tables of results for publication in Volume IV of the Annals of the Observatory. Under Mr. Fowle’s direction, the Mount Wilson observations of 1919 were reduced and compared with those obtained by Smith- sonian observers in Chile. An experiment had been made in using rolled stellite instead of cast stellite to prepare new spectroscope mirrors for the South American work. As these mirrors were not quite finished when Director Abbot went south to observe the eclipse of May 28 (as related in last year’s report) he took with him the Mount Wilson spectroscope mirrors, intending that the new ones should replace them on Mount Wilson. Unfortunately, they proved unsuitable owing to a gradual alteration of figure after completion, but were nevertheless used on Mount Wilson by Mr. Aldrich for the experiments of 1919. The matter is mentioned here because the defective mirrors intro- duced stray light in the spectrum, which led to a systematic error of 2 101 102 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. per cent (in defect) in the Mount Wilson solar constant values of 1919. Considerable additional labor was required in the reductions on this account. Furthermore, the sky was unusually hazy and streaky on Mount Wilson in 1919, which also added to the labor and anxiety of determining the best values from the observations. Agreement of Mount Wilson and Chilean work.—However, the re- sults when finally worked out proved to agree excllently, except for the systematic error above mentioned, with the results obtained in Chile. Both stations showed simultaneous and nearly equal fluctua- tions of solar radiation through a range of about 5 per cent. After allowing for the aforesaid 2 per cent systematic error of Mount Wil- son, the average deviation of the two stations was but 0.013 calorie, or 0.65 per cent from all the values, about 50 in number, obtained on corresponding days. Omitting five values very discordant, when the Mount Wilson sky was very hazy and streaky, the average devia- tion of the remaining days was about 0.008 calorie, or 0.4 per cent. Solar variation confirmed by observations of Saturn.—F rom corre- spondence with Dr. Guthnick, of the Berlin-Babelsberg Observatory, a most interesting confirmation of the solar variability has appeared. _ Variations of brightness of the planet Saturn from January to May, 1920, were shown by Dr. Guthnick’s photo-electric observations which could not be accounted for after allowance for all known sources of variability. These outstanding variations were found to be in almost exact correlation with fluctuations of the solar radiation as observed | at Calama, Chile. One per cent increase in solar radiation was found to accompany 1 per cent increase of Saturn’s brightness. These results, however, were only derived in connection with one of | two possible interpretations of the nature of solar variation. The sun might vary in such a manner that its changes would be observed simultaneously in all directions and so would occur on identical days on all the planets. This hypothesis does not fit the available observa- | tions of the sun and Saturn. On the other hand, the solar radia- | tion may be unequal in different directions. Such inequalities are, | in fact, indicated by the ragged raylike structure of the solar corona. On this hypothesis a change of solar radiation would occur as ray after ray strikes the earth in the course of the sun’s rotation upon its axis. These same unequally intense rays would reach the planet Saturn either before or after they reached the earth, according to the relative heliocentric longitudes of the earth and Saturn. The sun rotates about 14° a day, so that the angular difference in posi- tion of the two planets is to be divided by 14° to indicate the number | of days allowance to be made between the dates of corresponding solar and Saturnian measurements. Proceeding on this second hypothesis, extraordinarily close corre- spondence between the variations of the sun and Saturn was found. | ——————— REPORT OF THE SECRETARY. 103 Further work of the kind is to be done at Saturn’s next opposition. It will be noted that this second hypothesis of the nature of the solar variation relieves us of the great difficulty of understanding how so immense a body as the sun could vary in radiation so rapidly as our observations indicate. We have now only to suppose that there are inequalities of radiation in different directions which may be due to the absorption or scattering of the rays in the coronal regions near the sun. These inequalities may persist with little alteration for weeks. We, however, note them as variations of solar radia- tion as they sweep by us in the course of the sun’s rotation on its axis. The honeycomb pyranometer.—Mr. Aldrich constructed two copies of a new instrument devised by Abbot and Aldrich for measuring “nocturnal radiation.” We call it provisionally the “honeycomb pyranometer.” In this instrument a long thin ribbon of “ therlo” re- sistance metal about one-half inch wide and one one-thousandth of an inch thick is bent in such a way as to make up into 200 cells of trian- gular cross section all included in a total cross-sectional area of about 1 inch square. The corners of the cells are electrically insulated with baked shellac so that a current of electricity can be caused to flow from end to.end of the ribbon and thus all around each cell. Radia- tion which enters the front of the cells from any source, if not ab- sorbed there is reflected to and fro within the cells till it reaches their rear ends. There its remnant emerges upon a silvered mirror in- clined at a small angle so as to throw back the rays to make a second course to and fro toward the front. Thus by repeated absorptions the rays are at length almost wholly converted into heat. The de- vice is, in short, a “black body.” But unlike other “ black-body ” re- ceivers, its central cells are protected from losses of heat to the sides by reason of the nearly equally warmed ceils surrounding them. Thus the instrument is almost as sensitive as a flat blackened strip, but possesses the valuable property of being fully absorbing, which a strip does not. The temperature difference between the central cells and the case of the instrument is indicated by thermoelectric ele- ments. By passing a proper electric current through the “therlo” ribbon the same temperature difference can be produced as by radia- tion. The known energy of the electric current becomes the desired measure of the energy of radiation, as in Angstrom’s pyrheliometer. Also the constant of the apparatus is calculable from the known di- mensions of it. It is possible, too, to observe the solar radiation with this instrument, and so to calibrate it. Measurements of this kind check very closely with the computed values. Messrs. Aldrich and Abbot made a series of measurements with the honeycomb pyranometer on various sources of radiation, includ- ing comparisons with the ordinary pyranometer on incandescent 104 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. lamps of different kinds, and also observations on large hollow radia- tors at different constant temperatures. Values of the constant of the fourth power law of radiation differing by only 1 per cent from the best accepted value were readily obtained in this latter work. On the whole the “honeycomb pyranometer” is an instrument of great promise for standard measurements. Heperiments on the constant “ sigma.”—In collaboration with Dr. C, E, Mendenhall, a new attempt was begun to devise means to measure the constant of radiation with greater certainty. Apparatus was devised and constructed in the Observatory shop for this pur- pose. There was not time to try it before the departure of Messrs. Abbot and Aldrich into the field, so that the apparatus was loaned to Dr. Mendenhall for trial at the University of Wisconsin. Field work at Mount Wilson.—Mr. Aldrich continued observing on Mount Wilson until October, 1919. As said above, the year was un- favorable both by reason of a defect in equipment and by reason of much haze, cirrus cloud, and streakiness of sky. Also on many days a curious wandering of the galvanometer needle occurred. This phenomenon has been noted at Mount Wilson occasionally in former years, but was unusually pronounced in 1919. By anticipation, it may be remarked that it occurred also very markedly in late July and in August, 1920. The march of the galvanometer spot in these wanderings is relatively slow. A centimeter or two back and forth upon the scale in one to two minutes is the usual magnitude. It occurs with the galvanometer unconnected to the bolometer. Reasta- ticising of the needle system till it turned in the earth’s field at the same rate as the supporting quartz fiber failed to cure the trouble. The Mount Wilson expedition was renewed in June, 1920, by Messrs. Abbot and Aldrich. Proposed station in Arizona.—The prevailing cirrus cloudiness and haziness at Mount Wilson in all recent years, greatly exceed- ing that which obtained from 1905 to 1910, when the station was new, has been very discouraging. Furthermore, the station is quite un- suitable for “solar-constant” work in winter and spring months owing to cloudiness. It is urgently desirable to observe the solar radiation daily, as far as possible, in the United States, in order to check the results which are being obtained by Smithsonian observers in Chile. Accordingly it seemed best to set up a station in the most cloud- less region of the United States, where the work could go on during the entire year. Chief Marvin, of the Weather Bureau, obligingly caused investigations to be made of various proposed sites in Cali- fornia, Nevada, and Arizona. The one of highest promise appeared to be on the Harqua Hala Mountain (elevation about 5,800 feet) near Wenden, Ariz. Congress was urged to appropriate $25,000 for the REPORT OF THE SECRETARY. 105 establishment of a first-rate “solar-constant” observing station at the best site, but the appropriation failed. At this juncture Messrs, Abbot and Marvin held a long discussion by correspondence and verbally as to the reality of the supposed solar variability, and its availability as a forecasting element, in view of the use being made of the Smithsonian solar observations in Chile by the Argentine and Brazilian weather bureaus. The discussion brought out very clearly the urgency of obtaining corroborative observations of the solar radiation daily in the United States. Fortunately the proposed new station obtained private financial support in the lack of congressional action, Mr, John A. Roebling, of Bernardsville, N. J., at Dr. Abbot’s solicitation, made a grant of $11,000 for promoting measurements of solar radiation. Mr. Roeb- ling made the condition that so much of this sum as necessary should be devoted to removing the Smithsonian station from the plain near Calama, Chile, to a mountain site above the reach of dust and smoke. Any balance remaining after this improvement of the Chilean station could be used for the removal of the Mount Wilson equipment to the Harqua Hala Mountain in Arizona, or for such other purpose as Dr. Abbot might prefer for the advance of the study of solar radiation. At. a cost of between $4,000 and $5,000 the Calama station was re- moved to a mountain about 10 miles south of Calama, where skies of extraordinary purity have been experienced. The removal was com- pleted and first observations made at the mountain shortly after the close of the fiscal year. Dr. Abbot visited Wenden, Ariz., and the Harqua Hala Mountain in the last week of June, 1920. Contracts were made for the erection on the summit of a stone and adobe building of two stories, a lower, partly underground, for observing, and an upper for quarters of ob- servers. This is to be ready for occupancy by September 15, 1920, when it is proposed to remove the “solar-constant ” observing equip- ment from Mount Wilson to Harqua Hala. The purpose of these improvements is to enable us to obtain nearly every day in the year first-rate check observations of the “ solar con- stant” of radiation at two stations remote from one another in the two hemispheres. Only thus is it possible to lay a firm foundation of solar observations extending over a considerable interval of time, which will enable meteorologists to determine if the sun’s variations are really of value as a weather-forecasting element. In view of the results published by Mr. H. H. Clayton, of the Argentine weather service, there is sufficient evidence that this may be the case to war- rant the expense and discomfort attending the continuous occupation of two desert mountain observatories like Harqua Hala and the Chilean station. 106 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920, Great appreciation is due Mr. John A. Roebling for his generous aid in stepping into the breach at this time when it proved impossi- ble to obtain public support for the urgent need. Only the most primitive equipment has, it is true, been possible on the Harqua Hala Mountain with the means available. Unfortunately, too, it means a considerable restriction of other interesting investigations under way or proposed, owing to the partial dismantling of the Mount Wilson station. This is greatly to be regretted. It is recommended that Congress be urged to appropriate the money needed to complete the independent equipment of Harqua Hala, so as to permit needed apparatus to return to Mount Wilson. The Harqua Hala station should also be relieved of its limitations of water, of accessibility, and of communication, and the buildings made more commodious. Other- wise it will be only at such personal sacrifice of comfort as few can be found willing to make that its work can go on. PERSONNEL, Miss Inez Ensign resigned as computer on September 22, 1919. Miss F. A. Graves returned as computer from leave for overseas work in France on September 4, 1919. Miss Gladys Thurlby, computer, married, on May 8, 1920, Mr. Albion M. Bond, but remained in the service of the Observatory. SUMMARY. The year has been marked by the practical completion for publi- cation of Volume IV of the Annals, but no appropriation is yet available for its publication. Close agreement in solar variation was found for 1918 and 1919 between results of Mount Wilson, Calif., and Calama, Chile, 4,000 miles apart. A further remarkable con- firmation of the solar variation comes from a comparison of Smith- sonian observations in Chile with photo-electric observation of the brightness of Saturn by Dr. Guthnick, of the Berlin-Babelsberg Ob- servatory. This comparison indicates that the nature of the rapid solar variation, consists in the rotation with the sun of rays of unequal brightness which strike the different planets successively in the order of their longitudes and fall one after the other upon the earth as the sun by rotation brings them into line with us. A new nocturnal radiation instrument, provisionally called the “ honeycomb pyrano- meter” on account of its cellular structure, and which employs the well-known hollow-chamber principle of the “absolutely black” body, but without loss of sensitiveness, has been successfully con- structed and tried. By the generosity of Mr. John A. Roebling, of New Jersey, it has been possible to remove the Chile station to a — REPORT OF THE SECRETARY. 107 mountain above the dust and smoke of its former plateau location, and also to erect a building on the Harqua Hala Mountain, in Arizona, to which the Mount Wilson solar-constant work will be removed in September, 1920. Respectfully submitted. C. G. Asgor, Director. Dr. C. D. Watcorr, Secretary, Smithsonian Institution. APPENDIX 6. REPORT ON THE INTERNATIONAL CATALOGUE OF SCIENTIFIC LITERATURE. Str: I have the honor to submit the following report on the opera- tions of the United States Bureau of the International Catalogue of Scientific Literature for the fiscal year ending June 30, 1920. At the beginning of the war six volumes of the eleventh issue were still to be published, and only one volume ofthe twelfth issue had appeared. In spite of the evident financial difficulty ahead of the Catalogue, the Royal Society decided that publication should be continued through the fourteenth issue, covering the year 1914. The deficit has since been met by generous contributions from the Royal Society, the Carnegie Corporation of New York, and other sources. All of the volumes of the thirteenth and fourteenth issues have now been published excepting those for Geology and Physiology of the four- teenth issue, which are both in advanced stages of preparation. Much of the material for the fifteenth and later issues is now in the hands of the Central Bureau awaiting only authority for its publi- cation. On account of the general upheaval felt among all international organizations as soon as war began, it became impossible for the International Catalogue to continue its work in the satisfactory manner which up to that time had characterized the enterprise. A brief review of the history and aims of the international organi- zation may be repeated in order that the future aims and plans may be better understood. When the publication was begun in 1901 it was for the purpose of satisfying a recognized demand for a complete authors’ and subject index of all current scientific literature. This demand was to be met by publishing in annual volumes, one for each recognized branch of pure science, a complete authors’ and subject index to its current liter- ature. Each branch of science was to be covered by volumes contain- ing complete citations of the author, title, and source of every original paper, comprising first an authors’ index and second a classified sub- 108 REPORT OF THE SECRETARY. 109 ject index so arranged by means of classification schedules that the literature on any subject in any of the sciences might be readily found. The schedules were issued prior to the publication of the first volumes of the Catalogue and were prepared in every case by special- ists who were careful to take into consideration the needs of scien- tists as well as of librarians and students. Provision was made to include new subjects and introduce new methods of reference as the demand arose, in recognition of the fact that practically all of the sciences are in a constant state of transition and that a plan satisfac- tory at one time would probably be inadequate to meet the needs of a later period. . Omitting the greater part of the intervening history of the work, it may be said that in 1910, at a conference held in London to discuss the affairs of the Catalogue, it was recognized that although changes had been made in many of the schedules, a general revision was neces- sary and a committee was appointed to superintend this revision. Authority was given to this committee by a resolution which reads as follows: That a committee be appointed to revise the schedules and to make such other alterations aS may be necessary in the form of issue of the Catalogue. That it may be an instruction to the committee that, so far as possible, the subject index be confined to abbreviated titles and authors’ names and numbers to serve as references to the authors’ index. Tt will thus be seen that plans were in preparation to greatly in- crease the usefulness of the Catalogue, but before they were put into effect the war came and all progress was necessarily checked, and although the war is now over, financial conditions still prevent the introduction of new and improved methods. In spite of the fact that the publication of the Catalogue was begun under financial diffi- culties, as no working capital was available, by 1914, when the war began, the receipts and expenditures practically balanced. The delay in the publication of the annual volumes is recognized as the most serious defect in the enterprise, but with this remedied, as it would have been but for the war, and with the schedule re- _ vision in effect as provided for in the resolution above quoted, it is undoubtedly true that the International Catalogue would now meet all practical requirements of an annual authors’ and subject cata- logue to the literature of pure science. A résumé of the condition of the work at present can not better be given than by quoting a statement made by Prof. Henry E, Arm- strong, who as dean of the enterprise and chairman of its executive committee, is of all persons connected with the Catalogue the one best fitted to report on its affairs. The progress made in the publication of the International Catalogue since its foundation in 1900 is nothing short of remarkable, Two hundred and forty- 110 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. two volumes have been published, indexing the scientific literature of the period 1901-1914, An extraordinarily broad, sound foundation has been laid and much helpful experience gained. ‘The difficulties that were expected to arise have either been nonexistent or were easily overcome. To have established so complete an organization on a thoroughly successful working basis is in itself a feat of no mean order and most creditable to all concerned, not only to the staff of the Central Bureau but also to the various regional bureaus. The real difficulty by which the work has always been hampered is want of a working capital; this has affected both the Central and the regional bureaus. Had funds been always available, publication would have been far more rapid and the work might have been more fully developed. Almost every criticism that has been leveled at the Catalogue involves its extension, and therefore additional expenditure. The International Catalogue was established primarily to meet the demands of scientific workers by furnishing an annual authors’ and subject catalogue and index to the literature of each of the recog- nized branches of science; but as it is now evident that a general revision of the methods of production will be necessary, as soon as international affairs become stabilized, it would appear advisable when this revision becomes operative to establish some form of co- operation with the many existing abstract journals and, so far as possible, to encourage and aid the establishment of abstract journals in sciences not already represented. This need for abstract journals is now pressing for recognition, especially in the United States, and the preparation and publication of abstracts is so akin to that of scientific yearbooks that economy of effort in the production of both branches of bibliography evidently demands a very close cooperation. These abstract journals, organized and directed by workers in the several sciences represented, would, when published, form the basis of the annual volumes of an authors’ and subject index similar to the present International Catalogue of Scientific Literature, pref- erably by the reorganization of that international project which already receives official recognition and support from practically all of the countries of the world, acting through some 30 regional bureaus. By some simply organized method of cooperation between the abstract journals and the Catalogue, both branches would mutually aid one another to a very great extent and would in practice act as one organization. The abstracts and citations published in the ab- stract journals would form the basis of the Catalogue, thereby greatly simplifying the work of the regional bureaus, which in turn would aid the abstract journals in many ways and relieve them of the necessity of publishing annual indexes, at present quite an ex- pensive and laborious undertaking. The abstract journals and annual indexes would together furnish to scientific investigators, librarians, and others interested in scientific subjects all that they severally | require. REPORT OF THE SECRETARY. i ie be Owing to the financial difficulty which has involved the Inter- national Catalogue since war began, the Royal Society, which since the beginning of the undertaking has been the financial sponsor of the Catalogue, has issued invitations to scientific academies and institutions to send delegates to a special conference to open on Sep- temper 28, 1920, in London to discuss the future of the International Catalogue. As the need for a catalogue of scientific literature is universally acknowledged, and as the present organization of the International Catalogue up to the time of the beginning of the war was meeting this demand in a more satisfactory manner than ever before, and as the present organization has behind it the official sup- port of all of the principal countries of the world, it appears obvious that every effort should be made to continue and improve the work rather than abandon it simply on account of temporary financial troubles and later have to reestablish the organization to cover the same ground. Many projects are now being promoted to publish abstracts, indexes, and catalogues of scientific publications, but the question of finance seems to be a common paramount difficulty, and it will certainly require less money to assure the success of the present organization than it would to organize and finance a new project. Very respectfully, yours, Leonarp C. GUNNELL, Assistant in Charge. Dr. Cartes D. Watcort, Secretary, Smithsonian Institution. APPENDIX 7. REPORT ON THE LIBRARY. Sir: L have the honor to submit the following report on the activi- ties of the library of the Smithsonian Institution during the fiscal year ended June 30, 1920: The receipts of publications compare most favorably with those of preceding years. Packages withheld from the mails during the war have begun to come in, and war regulations limiting exchanges have been largely removed. Although many societies were forced to limit distribution or to suspend publication during the war, it is expected that the receipts will continue to increase when shipments through the international exchanges may again be made between the United States and the Central Powers. The receipts for the year ended were 23,810 packages, 22,495 of which were received by mail and 1,315 through the international exchanges. Eight hundred and eighty volumes were completed and 14,273 entries were made. The library has suffered, however, from a lack of cataloguers to | carry on the work. The question of salaries for cataloguers in the — library is a serious one, as those doing similar work elsewhere are — receiving at least 33 per cent more. One desk has been vacant for | practically the entire year, and as the staff already was very small this has been a serious handicap. SMITHSONIAN MAIN LIBRARY. Publications for the Main Library, after entry on the records, are forwarded to the Library of Congress for deposit in. the Smith- sonian Division. The accession numbers for the year extended from 532,003 to 534,618, the accessions including 3,634 volumes, 186 parts, 157 pamphlets, and 42 charts. : The cataloguing covered 2,332 volumes and 32 charts; 848 volumes: were recatalogued ; 2,280 cards were typewritten and 618 cards from | the Library of Congress, for publications deposited there by the In- stitution, were filed in the catalogue; 3,756 public documents were | 112 . tt Ve eo 2 aa REPORT OF THE SECRETARY. 113 presented to the Library of Congress in accordance with the estab- lished practice. Dissertations were received from the Universities of Toulouse, Paris, Utrecht, Lund, Ghent, Helsingfors, Bonn, Basel, Lausanne, Zurich, and Geneva. The securing of publications in exchange for the completion of sets has been continued, with the following results: Number of want cards received from Library of Congress: Hrom Smithsonian’ Divisions gh) abilie wae Sound “att VPI ik 176 ron eeriodical: Divisio.) 2 ee Boe eA eM 79 RUPERT ACE CLOT CEE USL Die ee ae 30 Ptaie tay tert erly yey Babe att are Ai TEE ii Oa ees 285 Number of publications secured for Library of Congress: HMMS TnNSOnIGT LU ISION oe es De ee 313 316 HemiPaniodical DivisionSo. SAGs 207 LUNE Oh ee 11 66 Morse rder oi wsione._ Po ae Other aS a IVS Ee 13 36 Ok Sd pel EE I lage yaar ell Sea sep eas TI 337 418 Number of sets completed, 73. With exchanges to the Central Powers still suspended, shipments delayed, and many societies suspending publication, the time for se- curing missing parts has been far from favorable. It is worthy of note, however, that in spite of the unfavorable conditions a larger proportion of the wants have been secured in exchange than in years previous, as may be seen by the following table: Want cards| Sets com- Years. rabeivellt pleted. Per cent. IRA Sie oS oo aa a onium Senge axe o tae eee tae ose 387 82 21.0 ee ee Bart PERSONS ON oS Se 35 Paes See oe oes Se oe Sean ceaaee sees 996 185 18.6 Ses CSE NS a oe ce es en ee ee eee 514 134 26.0 Requests sent out for missing parts, it will be seen, are more effec- tive by 5 per cent than those sent out before the war. It is hoped that when shipments to the Central Powers through the Interna- tional Exchange Service are resumed and overseas shipments can be delivered more promptly that still better results can be secured. SMITHSONIAN OFFICE LIBRARY. The accessions for the office library amounted to 300 volumes and 7 pamphlets, not including the set of publications of the Carnegie Institution of Washington, numbering more than 300 volumes, which has been placed on deposit by Secretary Walcott. In order to pro- vide adequate shelving space for these volumes it was necessary to 42803 °—22——8 114 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. rearrange the books already in the reference room, and as a result practically all of the shelving space is now occupied. The circula- tion of books in the reference room was 218 volumes. Aeronautical collection—The aeronautical collection, as in the past, has been consulted by students of aeronautics of foreign coun- tries as well as those of the United States. Additional cases in the hall of the Smithsonian Institution have been set aside for the accom- modation of this collection, so that it is now more accessible to the public. Forty new titles were added during the year. De Peyster collection.—Author cards for the Napoleon series, num- bering more than 1,200 volumes, have been made, and the books have been arranged in regular order in the cases in the hall of the Smith- sonian Institution. Author cards have been made also for the series in British, German, and Italian history. Reading room.—The number of magazines loaned during the year from the reading room was 2,907, a decrease of 233, as compared with the preceding year. The service has suffered from the fact that no binding could be done, owing to the exhaustion of the funds avail- able for this purpose. Employees’ library—The increased use of the employees’ library is noteworthy. Six hundred and forty-one volumes were loaned, as compared with 332 last year. MUSEUM LIBRARY. There have been no additions to the Museum library of exceptional importance. Valuable material has been contributed, however, by Dr. Charles D. Walcott, Mr. W. R. Maxon, Maj. Gen. John R. Brooke, Dr. A. J. Boving, Dr. F. H. Knowlton, Dr. J. M. Aldrich, Dr. W. H. Holmes, Dr. Mary J . Rathbun, Dr. W. H. Dall, Dr. O2-Re Hay, Mr. William Schaus, Dr. C. W. Richmond, Mr. Austin H. Clark, Dr. Walter Hough, Mr. A. N. Caudell, and the Knab estate. Accessions.—Two thousand five hundred and forty-eight accessions were received during the year, including 1,932 completed volumes and 1,581 pamphlets. The number of books in the library is now 145,307; including 56,617 volumes and 88,690 parts of volumes and pamphlets. Periodicals —Vhirteen thousand four hundred and thirty-two pe- riodicals were entered during the year; 2,619 section cards for periodi- cals and 858 section cards for volumes were made. The number of new cards for periodicals was 351. Cataloguing—The number of catalogue cards added was 2,748; 744 books and 1,529 pamphlets were catalogued. Loans.——The number of books loaned out was 9,802. Of these, 2,145 books, including 1,951 from the Library of Congress, were bor- rowed from other libraries. Fully as many volumes were consulted, but were not taken out. REPORT OF THE SECRETARY. 115 Binding.—Owing to the increasing cost of binding, the library’s funds allotted for that purpose were exhausted in January, 1920. As will be seen by the figures below, the library’s allotment for bind- ing has not kept pace with the increases in cost. As a consequence the number of books sent to the Government bindery has been steadily decreasing. Following are the number sent during the past three fiscal years: pnae taka avi tA see iets NL toh 8 1, 706 0, orem. © he hc 8 Ce 2 1, 322 Lol pd gangs aindln, «<0, Coe]. caer pacmt eealinllies aia raetmesnats 737 With a constantly increasing supply of volumes and many pub- lications received during the present and past fiscal years still un- bound, the library is greatly handicapped and is unable to render the service that it should. Technological series——Additions to the technological library dur- ing the year, exclusive of duplicates, number 200 bound volumes, 2,983 pamphlets, and 2,576 periodicals; 2,245 cards have been added to the scientific depository catalogue. A special effort has been made to complete the files of publications, especially United States Gov- ernment documents. The books and periodicals loaned during the year were 200. Sectional libraries——Following is a complete list of sectional libraries: Administration. Marine invertebrates. Administrative assistant’s office. Materia medica. Anthropology. Mechanical technology, Biology. Mesozoic fossils. Birds. Minerals. Botany. Physical anthropology. Comparative anatomy. Prehistoric archeology. Editor’s office. Property clerk. Ethnology. Registrar’s office. Invertebrate paleontology. Reptiles and batrachians, Mammals. Superintendent’s office. BUREAU OF AMERICAN ETHNOLOGY LIBRARY. A report of the operations of the library of the Bureau of Ameri- can Ethnology will be found in the report of that bureau. This library is administered under the direct care of the chief of the bureau. ASTROPHYSICAL OBSERVATORY LIBRARY. Further additions to the library of the Astrophysical Observatory number 87 volumes, 10 parts of volumes, and 16 pamphlets. 116 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. NATIONAL ZOOLOGICAL PARK LIBRARY. To the National Zoological Park library there were added six volumes and two pamphlets. SUMMARY OF ACCESSIONS. The accessions during the year, with the exception of those in the library of the Bureau of American Ethnology, may be summarized as follows: To the Smithsonian deposit in the Library of Congress, including parts toyecomplete.Sets= 220. 6 a ee 4, 019 To the Smithsonian office, Astrophysical Observatory, and National Aooltozical, Parki libraries... £2. cence otk es Sewer Beet ee ee 428 To the United States National Museum library________-_______-.___-___ 2, 548 Ota) 2 3) 2 pe a ae a ee ee a ee eee 6, 995 Respectfully submitted. Pau Brockert, Assistant Librarian. Dr. Cuartes D. Watcort, Secretary, Smithsonian Institution. APPENDIX 8. REPORT ON THE PUBLICATIONS. Sm: I have the honor to submit the following report on the pub- lications of the Smithsonian Institution and its branches during the year ending June 30, 1920: The Institution proper published during the year 14 papers in the series of Miscellaneous Collections, 1 annual report and pam- phlet copies of 20 articles in the appendix to the report, and 1 special publication. The Bureau of Ethnology published 1 annual report and 3 separate papers from the same report, and 4 bulletins. The United States National Museum issued 1 annual report, 3 volumes of the proceedings, 33 separate papers forming parts of these and other volumes, 5 bulletins, and 9 separate parts of bulletins. The total number of copies of publications distributed by the In- stitution and its branches was 148,290, which includes 157 volumes and separates of the Smithsonian Contributions to Knowledge, 24,949 volumes and separates of the Smithsonian Miscelianeous Collections, 16,720 volumes and separates of the Smithsonian annual reports, 81,936 volumes and separates of National Museum publications, 16,761 publications of the Bureau of American Ethnology, 1,958 special publications, 19 volumes of the Annals of the Astrophysical Observatory, 23 reports on the Harriman Alaska Expedition, and 564 reports of the American Historical Association. SMITHSONIAN MISCELLANEOUS COLLECTIONS, Of the Miscellaneous Collections, volume 67, 2 papers were issued ; volume 69, 2 papers; volume 70, 3 papers; volume 71, 5 papers; vol- ume 72, 2 papers; in all, 14 papers, as follows: VOLUME 67. No. 5. Cambrian Geology and Paleontology. IV, No. 5. Middle Cambrian Algae. By Charles D. Walcott. December 26, 1919. Pp. 217-260, pls. 43-59. (Publ. 2542.) No. 6. Cambrian Geology and Paleontology. IV, No. 6. Middle Cambrian Spongiae. By Charles D. Walcott. April 21, 1920. Pp. 261-364, pls. 60-90. (Publ. 2580.) 117 ‘118 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. VOLUME 69. No. 1. Smithsonian Meteorological Tables. August 19, 1919. 261 pp. (Publ. 2493. ) No. 5. Mammals of Panama, By Edward A. Goldman. April 22, 1920. 309 pp., 89 pls. (Publ. 2498.) VOLUME 70. No. 2. Explorations and field-work of the Smithsonian Institution in 1918. July 15, 1919. 122 pp., 127 figs. (Publ. 2535.) No. 3. Archeological investigations at Paragonah, Utah. By Neil M. Judd. July 15, 1919. 22 pp., 15 pls. (Publ. 2536.) No. 4. Temperature variations in the North Atlantic Ocean and in the atmos- phere. Introductory studies on the cause of climatological variations. By Bjorn Helland-Hansen and Fridtjof Nansen. Hodgkins Fund. April 17, 1920. 408 pp., 48 pls. (Publ. 2587.) VOLUME 71. No. 2. A method of reaching extreme altitudes, By Robert H. Goddard. December 80, 1919. 69 pp., 10 pls. (Publ. 2540.) No. 8. Variation in solar radiation and the weather. By H. Helm Clayton (introductory note by C. G. Abbot). January 15, 1920. 53 pp., 5 pls. (Publ. | 2544. ) No. 4. The brightness of the sky. By A. F. Moore and L. H. Abbot. Hodgkins | Fund. February 4, 1920. 36 pp. (Publ. 2545.) | No. 5. Observations of the total solar eclipse of May 29, 1919. By C. G. Abbot and A. F. Moore. January 31, 1920. 12 pp., 1 pl. (Publ. 2578.) No. 6. New species of piper from Panama. By Casimir de Candolle. Feb- ruary 12, 1920: 17 pp. (Publ. 2579.) VOLUME 72. No. 1. Explorations and field-work of the Smithsonian Institution in 1919. May 8, 1920. 80 pp., 77 figs. (Publ. 2581.) No. 2. Two new East African primates. By N. Hollister. January 22, 1920. 2 pp. (Publ. 2582.) SMITHSONIAN ANNUAL REPORTS. REPORT FOR 1917. The complete volume of the Annual Report of the Board of Regents for 1917, together with pamphlet copies of the papers in the general appendix, was received from the Public Printer during the year. Annual Report of the Board of Regents of the Smithsonian Institution, show- ing operations, expenditures, and condition of the Institution for the year ending June 30, 1917. xii-+-674 pp., 241 pls. (Publ. 2502.) The appendix contained the following papers: Projectiles containing explosives, by Commandant A. R. 16 pp. (Publ. 2508. ) Gold and silver deposits in North and South America, by Waldemar Lind.- gren. 27 pp. (Publ. 2504.) REPORT OF THE SECRETARY. 119 The composition and structure of meteorites compared with that of terres- trial rocks, by George P. Merrill. 14 pp., 9 pls. (Publ. 2505.) Corals and the formation of coral reefs, by Thomas Wayland Vaughan. 88 pp., 37 pls. (Publ. 2506.) The correlation ef the quaternary deposits of the British Isles with those of the continent of Europe, by Charles E. P. Brooks. 99 pp. (Publ. 2507.) Natural history of Paradise Key and the near-by everglades of Florida, by W. E. Safford. 58 pp.,.64 pls.. (Publ. 2508.) Notes on the early history of the pecan in America, by Rodney H. True. 14 pp. (Publ. .2509.) Floral aspects of the Hawaiian Islands, by A. S. Hitcheock. 14 pp., 25 pls. (Publ. 2510.) The social, educational, and scientific value of botanic gardens, by John ' Merle Coulter. 6 pp. (Publ. 2511.) Bird rookeries of the Tortugas, by Paul Bartsch. 32 pp., 38 pls. (Publ. mel2.,.) Catalepsy in Phasmidae, by P. Schmidt. 5 pp. (Publ. 2513.) An economic consideration of orthoptera directly affecting man, by A. N. Caudell. 8 pp. (Publ. 2514.) An outline of the relations of animals to their inland environments, by Charles C. Adams. 28 pp. (Publ. 2515.) The National Zoological Park—A popular account of its collections, by N. Hollister. 51 pp., 46 pls. (Publ. 2516.) The sea as a conservator of wastes and a reservoir of food, by H. F. Moore. 14 pp. 8 pls. (Publ. 2517.) .. =~ — yp Ee KO eee Ty ee es Ojibway habitations and other structures, by David I. Bushnell, jr. 9 pp., 6 pis.’ (Publ: “2518.) National work at the British Museum—Museums and advancement of learn- ing, by FP. A. Bather. 1.15: pp. (Publ. 2519.) Leonard Fuchs, physician and botanist, 1501-1566, by Felix Neumann. i3 pp., « pls. (Publ. 2520.) In memoriam—Hdgar Alexander Mearns, 1856-1916, by Charles W. Richmond. i4°pp., 2 pi. °(Publ.2521.) William Bullock Clark. 4 pp. (Publ. 2522.) REPORT FOR 1918. The general appendix to the report for 1918, which was still in press at the close of the year, contains the following papers: 1. The discovery of helium, and what came of it, by C. G. Abbot. 2. An account of the rise of navigation, by R. H. Curtiss. 3. The tornadoes of the United States, by Robert DeC. Ward. 4. Wind power, by James Carlill. 5. A tribute. Samuel Pierpont Langley: Pioneer in practical aviation, by Henry Letfmann. 6. Modern physics, by R. A. Millikan. 7. The experiments of Dr. P. W. Bridgman on the properties of matter when under high pressure. Introductory note by C. G. Abbot. 8. The problem of radioactive lead, by Theodore W. Richards. 9. Sphagnum moss; war substitute for cotton in absorbent surgical dress- ings, by George E. Nichols. 10. History of military medicine and its contributions to science, by Col. W. P. Chamberlain, 120 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 11. Some problems of international readjustment of mineral supplies as indi- cated in recent foreign literature, by Eleanora F. Bliss. 12. Reptile reconstructions in the United States National Museum, by Charles W. Gilmore. 13. A Pleistocene cave deposit of western Maryland, by J. W. Gidley. 14, Paleobotany: A sketch of the origin and evolution of floras, by Edward W. Berry. 15. The direct action of environment and evolution, by Prince Kropotkin. 16. The law of irreversible evolution, by Branislav Petronievics. 17. The fundamental factor of insect evolution, by 8S. S. Chetverikov. 18. The psychic life of insects, by EH. L. Bouvier. 19. Sexual selection and bird song, by Chauncey J. Hawkins. 20. Marine camoufleurs and their camouflage: The present and prospective Significance of facts regarding coloration of tropical fishes, by W. H. Longley. 21. Foot-plow agriculture in Peru, by O. F. Cook. 22. Sun worship of the Hopi Indians, by J. Walter Fewkes. 23. The League of the Iroquois and its constitution: A constitutional league of peace in the Stone Age of America, by J. N. B. Hewitt. 24, The problem of degeneracy, by H. I. Tredgold. 25. History in tools, by W. M. Flinders Petrie. 26. The background of Totemism, by E. Washburn Hopkins. 27. A great naturalist: Sir Joseph Hooker, by Sir H. Ray Lankester. REPORT FOR 1919. The report of the executive committee and proceedings of the Board of Regents of the Institution and report of the Secretary, both forming part of the annual report of the Board of Regents to Con- gress, were issued in pamphlet form in November, 1919. Report of the executive committee and proceedings of the Board of Regents of the Smithsonian Institution for the year ending June 30, 1919. 18 pp. (Publ. 2548.) Report of the Secretary of the Smithsonian Institution for the year ending June 30, 1919. 106 pp. (Publ. 2547.) The general appendix to this report was in preparation but did not go to the printer until shortly after the close of the year. SPECIAL PUBLICATIONS. The following special publication was issued: Publications of the Smithsonian Institution issued between October 16, 1918 and July 16, 1919. August 12,1919. 1p. (Publ. 2541.) PUBLICATIONS OF THE UNITED STATES NATIONAL MUSEUM. The publications of the National Museum are: (a) The annual re- port to Congress: (6) the proceedings of the United States National Museum; and (c) the Bulletin of the United States National Museum, which includes the Contributions from the United States National Herbarium. The editorship of these publications is vested in Dr. Marcus Benjamin. REPORT OF THE SECRETARY. dig During the year ending June 30, 1920, the Museum published 1 annual report, 3 volumes of the proceedings, 33 separate papers form- ing parts of these and other volumes, 5 bulletins, and 9 separate parts of bulletins. The issues of the proceedings were as follows: Volumes 54, 55, and 56. The issues of the bulletins were as follows: Bulletin 103. Contributions to the geology and paleontology of the Canal Zone, Panama, and geographically related areas in Central America and the West Indies. Prepared under the direction of Thomas Wayland Vaughan. Bulletin 106 (text). North American early Tertiary Bryozoa, by Ferdinand Canu and Ray S. Bassler. Bulletin 107. Life histories of North American diving birds. Order Pygopodes. By Arthur Cleveland Bent. Bulletin 108. A revision ef the nearctic termites, by Nathan Banks, with notes on biology and geographic distribution, by Thomas E. Snyder. Contributions from the United States National Herbarium, volume 21. Flora of the District of Columbia and vicinity, by A. S. Hitchcock and Paul C. Standley. Of the separate papers of bulletins, the following were issued : Bulletin 100. Contributions to the biology of the Philippine Archipelago and adjacent regions. Volume 1, part 6: The relationships of the genera Cal- earina, Tinoporus, and Baculogypsina as indicated by recent Philippine mate- rial, by Joseph A. Cushman. Volume 2, part 38: Pyrosoma—A taxonomic study based upon the collections of the United States Bureau of Fisheries and the United States National Museum, by Maynard M. Metcalf and Hoyt S. Hopkins. Bulletin 103. Contributions to the geology and paleontology of the Canal Zone, Panama, and geologically related areas in Central America and the West Indies. Pages 189-524: Fossil corals from Central America, Cuba, and Porto Rica, with an account of the American Tertiary, Pleistocene, and recent coral reefs, by Thomas Wayland Vaughan, Of the remaining separates, 4 formed parts of volume 20 and 2 of volume 22, contributions from the United States National Herbarium, while 1 was from volume 55, 16 from volume 56, and 16 from volume 57 of the proceedings. PUBLICATIONS OF THE BUREAU OF AMERICAN ETHNOLOGY. The publications of the bureau are described in detail in Appendix 2 of this report. The editorial work of the bureau is under the direction of Mr. Stanley Searles, editor. During the past year four bulletins, the Thirty-third Annual Re- port, and three separates from this report were published, as follows: Bulletin 60. Handbook of Aboriginal American Antiquities. By W. H. Holmes. 380 pp. Bulletin 68. Structural and Lexical Comparison of the Tunica, Chitimacha, and Atakapa Languages. By John R. Swanton. Bulletin 69. Native Villages and Village Sites East of the Mississippi. By David I. Bushnell, jr. 111 pp., 17 pls. Bulletin 70. Prehistoric Villages, Castles, and Towers. By J. Walter Fewkes. 79 pp., 33 pls, 122 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. Thirty-third Annual Report—Accompanying Papers: (1) Uses of plants by the Indians of the Missouri River region (Gilmore); (2) Preliminary account of the antiquities of the region between the Mancos and La Plata Rivers in southwestern Colorado (Morris); (3) Designs on prehistoric Hopi pottery (Fewkes) ; (4) The Hawaiian romance of Laie-ika-wai (Beckwith). 677 pp. 95 pls. ; Three separates from the Thirty-third Annual Report. There were in press at the close of the year five annual reports and nine bulletins. The bulletins were as follows: Bulletin 67. Alsea Texts and Myths (Frachtenberg). Bulletin 71. Native Cemeteries and Forms of Burial East ef the Mississippi (Bushnell). Bulletin 72. The Owl Sacred Pack of the Fox Indians (Michelson). tf Bulletin 78. Harly History of the Creek Indians and their Neighbors (Swar- ton). Bulletin 74. Excavations at Santiago, Ahuitzotla, D. F. Mexico (Tozzer). Bulletin —. Northern Ute Music (Densmore). Bulletin —. Mandan and Hidatsa Music (Densmore). Bulletin —. Handbook of the Indians of California (Kroeber). Bulletin —. Archeological Investigations in the Ozark Region of Central Missouri (Fowke). REPORT OF THE AMERICAN HISTORICAL ASSOCIATION. The annual reports of the American Historical Association are transmitted by the association to the Secretary of the Smithsonian Institution, and are communicated to Congress under the provisions of the act of incorporation of the association. Volume 2 of the report for 1916 was published during the year, and the reports for 1917 and 1918 were in press at the end of the year. RHPORT OF THE NATIONAL SOCIETY OF THE DAUGHTERS OF THE AMERICAN REVOLUTION. The manuscript of the Twenty-second Annual Report of the Na- tional Society of the Daughters of the American Revolution was _ transmitted to Congress according to law in June, 1920. THE SMITHSONIAN ADVISORY COMMITTEH ON PRINTING AND PUBLICATION. The Smithsonian advisory committee on printing and publication passes upon all manuscripts offered for publication by the Institu- tion or its branches and considers all forms of routine, blanks, and such other matters as pertain to printing and publication. Ten meet- ings were held during the year and 93 manuscripts were acted upon. Respectfully submitted. W. P. True, /ditor. Dr. Cuartes D. Watcort, Secretary of the Smithsonian Institution- REPORT OF THE EXECUTIVE COMMITTEE OF THE BOARD OF REGENTS OF THE SMITHSONIAN INSTITUTION FOR THE YEAR ENDING JUNE 30, 1920. To the Board of Regents of the Smithsonian Institution: Your executive committee respectfully submits the following re- port in relation to the funds, receipts, and disbursements of the insti- tution and a statement of the appropriations by Congress for the National Museum, the international exchanges, the Bureau of Ameri- can Ethnology, the National Zoological Park, the Astrophysical Ob- servatory, the International Catalogue of Scientific Literature, etc., for the year ending June 30, 1920, together with balances of previous appropriations: SMITHSONIAN INSTITUTION. Condition of the fund July 1, 1920. The sum of $1,000,000 deposited in the Treasury of the United States under act of Congress is a permanent fund, having been ac- cumulated by the deposit of bequests from time to time. Subsequent bequests and the income therefrom are invested in approved securi- ties. The several specific funds so invested are now constituted as follows and classed as the consolidated fund: eitiotoinien CONeEPAL TUNG See ee ee Bee $37, 275. 00 ERUTERESGIBRITEN Ohare) been et ©. Sek AA be Vie ed ee ee ae 117. 00 care Tea (0 Ye Soe aie ee Pee oor OST E. EAN CREP AROS Votes See eener One Serr ame 16, 898. 84 Pune RG UN (oboe el ee a eg, ee ee 2, 150. 00 Bucy andsGeorge W. Poore fund=25 4+ 2-4 ee 4, 968. 00 PERE EP ES) SANTOUC: MIMO. - a ois ee oe Sg es Eee 221.00 PRPALNTIUSTAMETUIEL Oe eos ee ee eee ee Se 1, 804. 00 Remaentatencerlsuitie (rice ae. SA SARS Beak ys teeth eee 10, 000. 00 Tessas LEE eEE ATES) 9076 RII RRS aR ate OR ASS Sr en rep me eee Ore eR ieee ree §, 355. 93 Hamilton fund —-—...._ 2" ne Ey ssa a Os Son tc pc el se le ed el ae 500. 00 SPI Sees ast) Prat te a en ee een er a ee Sohn Ta (oral consolidated’ fund. 2-2 2 ee eer ru 82, 896. 02 Several lots of unimproved land near the city of Lowell, Mass., forming a part of the legacy known as the Lucy T. and George W. Poore fund, were sold during the year and the sum of $440.07 was realized and invested. 123 124 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. Statement of receipts and disbursements from July 1, 1919, to June 30, 1920. RECEIPTS. Gashvon-depositvand ime satedielyes, lOO se ee ee $2, 122. 78 Interest on fund in United States Treasury $60, 000. 00 Otters INTCrES Gs =e aS ARs oe ee 5, 651. 37 $65, 651. 37 Repayments, rentals, publications, ete__________-_-_-__ 14, 525. 09 Contributions for specific purposes_____-—__ --_ = -_ 41,171. 82 Bills receivable 2-2 SS 50, 000. 00 Proceeds trom) sale’of real estate. eee 440. 07 ——————- 171, 788. 35 173, 911.13 DISBURSEMENTS Buildings; care: amd repel ire fa. el ah, ip ile a Bal 9, 618. 05 USM Grom y BUDA eee W OV Qa OD-4 rl) Uy s< (ae ee aig Pea ee I Mes a EN eee Une Veena 1, 599. 44 General expenses: St) SH iy (eS ee Se Ae Dek oe Va ead Me el we Bd A MA DI Ae eee 21, 124. 74 IM CGS Re TLS Jace) APRA ek ble CaF ASA ARDS 124. 00 Stabionenyacsscz | nel iboats bry Dies sapere 648. 09 Postage, telegraph, and telephone___________-______ 736. 34 Hreronie eS. Pak Ue Ae eee oa Ae EEE Wee ee T2 $2 Incidentals, fuel, and lights!22s2s pes pacer ries 885. 93 Guar aig el ee he CN Ae ie OE Sy eh OES re at oe 1, 079. 29 ——_—_—_——_ 24, 671. 21 STAID TAR yin A Sa a Bn il ES et oS ea Bt ge, ERO Bae eed 2, 888. 03 Publications and their distribution : Miscellaneous scollections: 26 = = Sn as 9, 277. 60 TREDOGUSTE. Mee tie Feet ed eae eee Sea ays eae 151. 19 Special) pubhGa tions! a2 a sere ee eee ee 10. 50 Publication supplies aves sh Se esa ee ee 2 So Salariesarsee rp are copay eee bret oe OPES ATL 7, 246. 82 Harriman. publica tionsiet sas eee te es 38. 82 —————— 16, 942.32 APE DLOTE bons sn Ge = ESE a T Cli Seiten aie ass Sees enema a ee eee Se ee 5, 784. 95 Hodgkins specific fund, researches, and publications_______________ 10, 044. 32 International-exchan veg 2202 2> 28 tS eka ey ee ee ee ee 1, 900. 37 Consolidated fund (invested) es HF ee ae Seeks eee 6, 995. 39 Bilissreceivable;-time-certinicatess = 2 a ee ee ee 40, 000. 00 Interest accrued, consolidated fund___--_--_-__--_--_-__--____-___ 78.99 Advanees-tor- held expenses, ete =o can ee ee ee eee 40, 088. 72 160, 606. 79 Deposited with Treasurer of the United States and THEA PHL OST a ae ne aR ERA So Re ie, Ae Pera ah al 2S Ae 138, 104. 34 Cash son Nand ees see ene ee ene ee rere eee Ree aan 200: 00 ——————_ 13, 304. 34 178, 911. 13 The itemized report of the auditor confirms the foregoing state- ment of receipts and expenditures, and is approved. A summary of the report follows: y REPORT OF THE EXECUTIVE COMMITTEE. 125 CapitaL AupiT Co., Pusiic ACCOUNTANTS & AUDITORS, Washingion, D. C. Executive Committee, Board of Regents, Smithsonian Institution. Sm: We have examined the accounts and vouchers of the Smithsonian Institution for the fiscal year ended June 30, 1920, and certify the following to be a correct statement: ce JDM Re Gh WO) Sp AS ES SS Se eS EY ees Cee k ao eee eed eee ae $171, 788. 35 PERS UIT SCEOET GG cee seo es sere oe eer Se Aes eens (Ss tee ee 160, 606. 79 Excess of receipts over disbursements______-_--___________ 11, 181. 56 SRT EONT PULY LOL ae tee en en SR 6: E-~ - Dovre pe 2,122.78 Batlerceton: hand.Jumers0; 1920s wa) cet STR rep 18, 304. 34 Balance as shown by Treasurer’s statement as of June 30,1920__.__ 14, 696. 41 BES OUtScanoine; Cheeks. 2402 2 eS EA ee ES eet yes 90h 5, 139. 16 PES TU EP TE) CBS Mass Bios Rl Bi a aR Tale As Seen ee eine tncs GER ert kee ts 9, 557. 25 Pane Amenean National Bank: > '- 0 28 Ree ash eee Re 3, 547. 09 Deenarerser ries ach enee eee. Df 8 Jo oN ee Pe ee ed 200. 00 ral ane bNe GO 1OZ0 ce a Sa ee en ee gg es 18, 304. 34 The vouchers representing payments from the Smithsonian income during the year, each of which bears the approval of the secretary or, in his absence, of the acting secretary, and a certificate that the materials and services charzed were applied to the purposes of the institution, have been examined in con- nection with the books of the institution and agree with them. CapiraL AupitT Co., By WItu1AM L. YArGEr, President. All payments are made by check signed by the secretary of the institution, on the Treasurer of the United States, and all revenues are deposited to the credit of the same account, except in some in- stances small deposits are now made in bank for convenience of col- lection and later are withdrawn in round amounts and redeposited in the Treasury. The practice of investing temporarily idle funds in time deposits has proven highly satisfactory. During the year the interest de- rived from this source has amounted to $1,320.60. Your committee also presents the following summary of appro- priations for the fiscal year 1920 intrusted by Congress to the care of the Smithsonian Institution, balances of previous appropriations at the beginning of the fiscal year, and amounts unexpended on June 30, 1920: 126 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. Available te oie International'Exchanges, 1918'ton IO! . 2S ES a. APE $893. 24 1$4.38 Intermational ‘Exchanges 29109. Diss: SSL. 025 steel. TNS Aes Tee BS 3, 794. 55 11.99 TNTeRBAbLONAl Te xCHAN SES, MOZOL co ec ms ce wlnenios st waindeasieecion sevedoe eases 45, 000. 00 9, 883. 06 MMNCHICA FPRNOLOPY LOLS. acd mace ceo ce eee ee See Bees ect doe cee caeecle 430. 21 1 353. 56 American Juthnology:, LOL0. 7 25e,cjatcs cine selene sise menace ceetoe terete ena aoe 5, 885. 29 722.75 Am onigan\ Eihnolory1Q20. 27s ct cetaclssels o Mek creme meine eendsaece sees 42, 000. 00 6, 495. 68 International Catalopue, 1018: 222. jo..j22 = -mcc- a tyseepeeisebel ht Bosse. seh 585. 10 1 220. 43 International! Catalogue, 1919... 2... ne ok ces ewe nine nin = ee Sc 1, 186. 75 910. 34 Intenaational@atslorwe TOL ns oe ke geiorcins oe Aeciers sae rsme os eects ee atets mints 7, 500. 00 1, 365. 70 Agtrophysical Observatory, 1918 on cisco cie tine mare ddan = gems SEE oe hy 230. 67 1 168. 67 ASiropuysiealo DservatOny, LOO. : occ sels os oe seen we amine ences eee rene 2, 663. 21 94.61 Astrophysieal Observatory ;1920: 205 &. 282. SR 2 ERs 13, 000. 00 770. 34 Obsdrwdtions: Pclipse.of Sun 918. ssnosoeces eee see ee eee cemoseis seme eee 1, 455. 33 1191.20 National Museum: Pir nr rure an deter hires Ot em em ca fee eee eee TRC EES OL CRT cm RICEE 48.14 1 48.14 Kurniture and fixtures, 1919.5 .¢5.ccs.c deere eT. 910.99 188. 98 MEGUMI ao Ct XPUeS O20 sen eneee seem eee eae eae ae seas en ee 20, 000. 00 2,022. 26 Heatinerand he hting (MOUS 6 eS ft a = ata! : : tt = at ; at tb ‘ : — ‘ sd * ve nr j . Eacare r j pall aa, wa t - ’ *% me t | F red ’ ar Z ’ F i = . ADVERTISEMENT. The object of the GenrraL Arrenpix to the Annual Report of the Smithsonian Institution is to furnish brief accounts of scientific dis- covery in particular directions; reports of investigations made by collaborators of the Institution; and memoirs of a general character or on special topics that are of interest or value to the numerous correspondents of the Institution. It has been a prominent object of the Board of Regents of the Smithsonian Institution, from a very early date, to enrich the an- nual report required of them by law with memoirs illustrating the more remarkable and important developments in physical and bio- logical discovery, as well as showing the general character of the operations of the Institution; and this purpose has, during the greater part of its history, been carried out largely by the publica- tion of such papers as would possess an interest to all attracted by scientific progress. In 1880 the Secretary, induced in part by the discontinuance of an annual summary of progress which for 30 years previous had been issued by well-known private publishing firms, had prepared by competent collaborators a series of abstracts, showing concisely the prominent features of recent scientific progress in astronomy, geology, meteorology, physics, chemistry, mineralogy, botany, zool- ogy, and anthropology. This latter plan was continued, though not altogether satisfactorily, down to and including the year 1888. In the report for 1889 a return was made to the earlier method of presenting a miscellaneous selection of papers (some of them origi- nal) embracing a considerable range of scientific investigation and discussion. This method has been continued in the present report for 1920. 143 ne 2 wo > a eee be * a i _ Si. ee ay ey Zz = « p - Cd Et = £ " t 4 : ‘ > as o c - i ~ pe © STUDYING THE SUN’S HEAT ON MOUNTAIN PEAKS IN DESERT LANDS. By C. G. ABsot. [ With 7 plates.] Asa little boy it used to please me greatly to see the potatoes in the cellar toward spring begin to stretch out long sprouts which had to be rubbed off from time to time. Sometimes one of the potatoes would fall through some crack where it became inaccessible, and its sprouts would grow and grow, sometimes a yard or more, till they came to a little streak of light, always white until the light was reached, but then tending toward green. Again it was a pleasure at the time, and is now a greater pleasure, to look back upon the march of the seasons with the northward and southward excursions of the sun, which changed the New England landscape by a gradual progress from the glories of winter to the beauties and fruitfulness of spring and autumn. In a world where the very life of all the plant kingdom depends upon sunlight, and where the existence of the temperature fit for all life of the anima! kingdom depends upon the sun’s rays, it may seem an extraordinary statement that until the beginning of the twentieth century no exact measurements of the intensity of the solar radiation on which all things depend had ever been obtained. Some- times one hears the inquiry as to whether the sun’s beams are gradu- ally losing their strength and the sun declining toward the condition of a cold body devoid of life-giving energy. It is impossible to answer this question other than to refer to the fact that the crops which were raised in Egypt and Syria in the most ancient recorded times were substantially identical with those that are raised there now, so at least the decline of the sun’s radiation has been very little in the last 6,000 years. The ancients, although having much astronomical knowledge, never measured, so far as we know, the intensity of the sun’s radiation, so that there are no accurate measurements to fall back upon in order to answer this question. 42803 °—22——_10 145 146 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920, It was not until the time of Sir John Herschel and Pouillet, in the — decade 1830-1840, that attempts were made to get accurate measure- — ments of the heat of the sun. And it was not until the decade 1900- — 1910 that the methods and apparatus for this purpose attained such perfection that results accurate to the order of 1 per cent were ob- tained. Inquirers who may live 1,000 years hence can, we hope, refer to the measurements of the Smithsonian Institution begun in 1902 in order to settle the question whether the sun’s heat has gradu- ally declined in the millennium intervening. If we could set up a tube reaching to the outer limit of the atmos- phere and large enough to see through it the whole of the disk of the sun, and exhaust the air from it entirely, then the measurements of the sun’s intensity of radiation would be very simple. But situated as we are underneath an ocean of air charged with dust, clouds, water vapor, carbon dioxide, and even, we may say, of the molecules them- selves, such solar researches are very difficult. In order to minimize these difficulties as far as possible, such studies are best conducted in the most dry and cloudless regions at high-altitude stations. In the course of the work carried on by the Smithsonian Institution measurements have been made at Washington, sea level; Bassour, Algeria, 3,600 feet; Hump Mountain, North Carolina, 4,800 feet; Mount Harqua Hala, Arizona, 5,600 feet; Mount Wilson, California, 5,800 feet; Calama, Chile, 7,500 feet; Montezuma, Chile, 9,500 feet; Mount Whitney, California, 14,500 feet; and finally from a free balloon which was sent up from Omaha, Nebraska, carrying automatic recording instruments, to an altitude of about 15 miles. The accuracy of these measurements has depended on the able cooperation of my colleagues, Messrs. F. E. Fowle, L. B. Aldrich, A. F. Moore, L. H. Abbot, and others, observers; Mr. A. Kramer instrument maker; and Miss F, A. Graves and others, computers. They have been made, some in summer, some in winter, some in clear skies, and others in skies made hazy by the dust from the gigantic eruption of Mount Katmai, Alaska, in 1912, but their results are in substantial agreement and give the mean value of the intensity of solar radiation to a probable ac- curacy of 1 per cent. I say the mean value because the investigations have shown that the sun’s output of radiation is not constant, but varies from year to year and even from day to day within the year. The solar variations of long interval seem to be associated with the general activity of the sun, so that higher values of the sun’s emis- sion are found when sun spots, prominences, faculae, and other solar phenomena are more than usually marked. At such times, strangely enough, the temperature at most weather stations on the earth aver- ages below the normal. This paradox of increased solar heat and de- creased terrestrial temperature may perhaps be explainable on the basis that increased cloudiness occurs at times of sun-spot activity. SUN’S HEAT—ABBOT. 147 It has long been known that the aurora borealis, or northern lights, have been particularly active at times of sun-spot maximum, and as these lights are electrical disturbances in our atmosphere, it has come to be believed that the sun furnishes not only light rays but also bombards us with electric ions. Electric ions are known from labora- tory experiments to promote the formation of clouds. Hence, it is quite possible that the electric bombardment of the earth by the sun, being more vigorous at times of sun-spot maximum, tends to promote cloudiness; which in turn indirectly, by reflecting away solar radia- tion, actually diminishes the amount available to warm the earth, although the direct tendency of increased solar activity is to increase the earth’s supply of radiation. The short irregular fluctuations in the sun’s radiation amount sometimes to 3 or even 5 or 7 per cent within a few days. Although they seem to be slightly associated with the rotation period of the sun, as if rays at different strength were sent out by the sun in differ- ent directions which, after a full rotation of the sun accomplished in 26 or 27 days, come round again in the direction of the earth, yet in general these fluctuations are nonperiodic and accordingly not pre- dictable. Lately their cause has received a very unlooked-for but probable explanation by comparison of the solar observations of the Smithsonian Institution at Calama, Chile, with photometric observa- tions of Doctor Guthnick of the Observatory of Berlin, Germany. Employing a photo-electric cell, Doctor Guthnick compared the brightness of the planet Saturn with the star Regulus during Janu- ary, February, March, April, and May, 1920. Shining by reflected sunlight, Saturn must vary if the sun varies. Doctor Guthnick, how- ever, on comparing his results with those reported from the Smith- sonian Institution on the brightness of the sun, could see no corre- spondence between the small solar and planetary fluctuations which occurred. In his comparison, however, he assumed that whatever changes might occur in the sun would make themselves felt in all directions simultaneously. This is not necessarily so, for if the sun should be surrounded by an obscuring atmosphere thicker in some directions than others, rays of different intensity would go out to different quarters; so that the earth, being in a certain direction from the sun, might receive rays of a different strength from those which were emitted in the direction of the planet Saturn. As the sun ro- tates upon its axis once in about 27 days (the actual time differs for different parts of the sun), the ray which reached the earth would sweep around perhaps in one, two, or three days to or from the posi- tion of Saturn at the time of Guthnick’s measurements, so that one would expect Saturn’s reponse to the change noted in the solar radia- tion perhaps two or three days later, or two or three days earlier, exactly according to the relative positions of the two planets. 148 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920, Starting from this hypothesis, the two kinds of observations were found to have come into complete accord, so that 1 per cent change in the sun corresponded with 1 per cent change in the brightness — of Saturn, just as it ought to do. We may then look upon the sun’s variation as of twofold origin. First, the long-period changes, as- sociated with sun-spot activity, depend upon increased general tem- perature of the sun’s surface, due to the increased circulation of the hot, dense gases of which the sun is composed. On the other hand, the short-period, irregular fluctuations are to be regarded as due to the inequality of the sun’s radiation in different directions, per- haps caused by the presence of an obscuring atmosphere of different thicknesses from place to place. MOUNT WHITNEY, It is now almost 40 years since the late Doctor §, P. Langley, third Secretary of the Smithsonian Institution, made his picturesque and famous expedition to Mount Whitney, California, to observe the radiation of the sun. The expedition was made possible by the gen- erous aid of the late William Thaw, of Pittsburgh. It went forward in a special car, carrying the observers and the whole equipment. Mount Whitney, 14,500 feet elevation, is by a few feet the highest mountain in the United States, exclusive of Alaska. In 1881 the region about it was but little settled and Indians were frequently met with. Accordingly, a detail of soldiers accompanied the expedition through the desert from. the stopping place of the car to the litle town. of Lone Pine, where the experiments were begun. Doctor Langley has often told me of the tremendous heat en- countered in the small tent where the spectrobolometer was set up at Lone Pine. The indications of the bolometer, that electrical ther- mometer capable of detecting temperature changes of the millionth of a degree, are recorded by a sensitive galvanometer. In the very unfavorable conditions of the little tent Doctor Langley told me that the spot of light from the galvanometer mirrer used to rush off the scale a meter long in a single minute of time, so that the ob- server there read and called out the position of the spot on the scale as fast as he could do so without knowing what sun rays, or if any, were being observed by the bolometer. All of these thousands of readings were graphically plotted and reduced with almost infinite labor to obtain the results of the solar observations. A little later the whole apparatus was moved nearly up to the Has of Mount Whitney, where, on the shore of a beautiful mountain lake, at more than 12,000 feet elevation, the work was repeated. A few partial observations were made by the expedition on the very summit of Mount Whitney, but conditions there were found to be “AANLIHMA LNNOIA] NO SYSAYASEO HOS YALTIAHS SUN’S HEAT—ABBOT. 149 too trying to warrant the labor of carrying the heavy apparatus up the last 2,000 feet over rugged rocks and precipices. In these experiments a new region of the spectrum was found lying beyond that which was previously recognized by Doctor Lang- ley in his work at Allegheny, and I have heard him describe the thrill of discovery as he roughly mapped out this new region lying far down beyond the visible end of the red. Almost 30 years later, at the recommendation of Director Campbell, of Lick Observatory, and the writer, the Smithsonian Institution erected on the summit of Mount Whitney a stone and steel building of three rooms, so as to enable observers who, for any reason, require the high altitude for their work to carry it on under conditions of comparative comfort. The first to occupy the new observing station was Director Camp- bell’s expedition of 19091 to determine the quantity of water existing in the atmosphere of the planet Mars. At the same time the writer observed there, with special spectrobolometric apparatus, to deter- mine whether measurements of the sun’s heat outside the atmosphere, which had been carried on at Washington and Mount Wilson, would have yielded different results had they been made at a station very much higher in altitude. The following selection from a letter of the writer shows how little the second “solar constant ” expedition to Mount Whitney was able to compete in impressiveness with the famous one of Doctor Langley: Mount WItson, Catuir., September 14, 1909. Dear Sir: I left Pasadena about. 9.30 p. m. August 19, and took the 11.30 p. m. train at Los Angeles for Mojave. I slept occasionally but with great fear lest I should be carried by Mojave, and at length reached there a little late, at 4.30 a. m. The train for Little Lake, mostly a freight train, left at 7 a. m., and, after stopping all along the way to shift and unload freight cars, reached Little Lake, 33 hours late, at6 p.m. I got supper there and started by auto stage at 6.15 p.m. Having three boxes of delicate apparatus, one of which I felt it necessary to carry in my arms, the ride of 50 miles from Little Lake to Lone Pine was not altogether pleasant. Two automobiles started together, but the one I was in stopped near Olancha, and nearly two hours of work failed to start it, so that all the passengers crowded into the other. We reached Lone Pine at 11.30 p. m. At 8.30 a. m. August 21, with Mr. William Skinner, of Lone Pine, as guide, and with a driver and animals to carry my baggage, I started for Mount Whitney. We camped at about 4 p. m. with Mr. Robinson and his packers at Big Meadow; elevation about 10,500 feet. I found that nearly all the material for the house had gone up to the top, and my boxes were at Robinson’s camp. Mr. Skinner and I left camp at 6 a. m. and arrived on the summit of Mount Whitney about 11 a. m. August 22. We found Mr. Marsh with four workmen. The walls of the building were done except gables and partitions, and the frame of the roof was up. The masons were laying the 1A Shelter for Observers on Mount Whitney, by C. G. Abbot, Smithsonian Mise. Coll. (Quarterly Issue), vol. 52, pt. 4, pp. 499-506. 1910. 150 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. walls of the little stone hut for my work, and they finished it, including the roof, that day. Several 6 by 6 tents had been loaned by Professor Campbell, and in these we cooked, ate, and slept. Ham, bacon, Mulligan stew, and flap- jacks were the staple foods. I had set up my apparatus mainly by Thursday night, August 26. Friday it snowed a little, but the house was finished Friday afternoon, August 27. Mr. Campbell, with Messrs. Albrecht, McAdie, Doctor Miller, Hoover, and Skinner, came about noon on Saturday, August 28. They arrived in a thunder- storm of sleet. Lightning struck near by just as they reached the door. It became partially clear on the following Wednesday, and Campbell secured good observations on Wednesday and Thursday nights. My own preparations were set back by the storm, so that I only got ready Thursday afternoon, September 2, Friday morning was beautiful, and I think my observations of that fore- noon were satisfactory. I took two bolographs also about 2 and 5 p. m. of Friday afternoon between clouds. On Saturday it snowed 4 inches. Mr. Campbell and party went down. They almost lost one mule among the rocks (had to leave the mule behind after two hours’ work, but it went down the trail the following Wednesday), and three others slid off of the ice on the east side*of the range and rolled a hundred feet or so. The Smithsonian has been so fortunate as not to have had any of the animals in its employ injured during the whole operations. After waiting several days without much improvement in the weather Mr. Marsh and I left on Wednesday, September 8. I hope it will be possible for me to complete my work up there next July or early August, when the weather will probably be better. In August, 1910, the writer again ascended Mount Whitney with Mr. Marsh, and in the course of 10 beautiful days there again set up the spectrobolometer and obtained excellent “solar constant” ob- servations. Simultaneous measurements made in 1909 and 1910 at Mount Wilson and Mount Whitney agreed within about 1 per cent and within the error of the determinations. Similar agreement had been obtained before that between simultaneous measurements at Wash- ington and Mount Wilson, so that there appears to be no effect on the “solar constant” results depending upon differences of altitude, at any rate up to 14,500 feet. MOUNT WILSON. With the establishment of the Carnegie Institution in 1902, many plans for work in all branches of science were submitted, among them one by Doctor Langley, then Secretary of the Smithsonian Institu- tion, on the measurement of solar radiation. He entertained the hope, which has since come very close to fruition, that a knowledge of the sun’s radiation, the losses which it experiences in passing through our atmosphere, its possible variability from time to time, would be such a boon to meteorological science as to be a basis for forecasts of long range such as might even parallel those of Joseph, who forecast the seven lean years and the seven years of plenty. Qe ee =~ * = = | . fete SUN’S HEAT—ABBOT. 151 The outcome of his recommendations did not lead to the establish- ment of this kind of work by the Carnegie Institution itself, but did lead to the most cordial cooperation on the part of their new Mount Wilson Solar Observatory through its director, Dr. George E. Hale, with Doctor Langley in the furtherance of his favorite investigation. On Doctor Hale’s invitation, an expedition from the Smithsonian Institution was prepared and went forward in charge of the writer in 1905 to Mount Wilson, California, where temporary buildings were erected and occupied each year except 1907 from 1905 to 1910, when a more suitable observatory was constructed of cement blocks. In 1913 a tower telescope was added to the equipment of the Smithsonian observatory on Mount Wilson, so that the whole now appears as in the illustration, plate 4. Just above the observing station is a cot- tage occupied as quarters for the observers. The situation is remark- able for its boldness, standing on the edge of an almost precipitous ravine which falls away almost immediately nearly a thousand feet. It overlooks the valley cities of Pasadena and Los Angeles and the ocean on the one side, while to the east lie the Sierra Madre Ranges with the 10,000-foot mountains San Antonio, San Bernardino, San Gorgonio, and San Jacinto plainly visible on clear days. A little nearer the summit of the mountain lies the wonderful Mount Wilson Solar Observatory of the Carnegie Institution where apparatus of the greatest ingenuity, power, and extreme size has been accumulated year by year, culminating in 1919 in the completion of the 100-inch reflector with its dome 100 feet in diameter. As one con- templates this collection of splendid astronomical instruments and compares them with the little telescope with which Argelander made his famous “ Durchmusterung ” of the northern heavens, it seems as if some of the dinosaurs had come to life and were disporting among the little lizards which snap up the flies in the sun on Mount Wilson. From 1905 until 1920, with the single exception of the year 1907, measurements of the solar radiation were made on Mount Wilson during the summer and autumn months by the Smithsonian observers. This body of observations, published in the Annals of the Smithsonian Astrophysical Observatory, Volumes II, III, and forthcoming Vol- ume IV, is the basis of our knowledge of the radiation of the sun, its variability and its relation to our atmosphere and to terrestrial tem- peratures. A hint of the existence of variations in the sun’s radiation had been obtained in 1903 at Washington. Errors associated with the work in such a cloudy and smoky atmosphere as that of this eastern city are so large that the result could not be at all certain. Beginning with the observations on Mount Wilson in 1905, every year has added some- thing to the certainty of the variation of the sun as well as to the accuracy of the methods of observation and the number of special 152 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920, pieces of apparatus developed for use in the investigation. Early in the work it was recognized that a standard instrument for precision measurements of the sun’s heat was required. By 1910 there was de- veloped the standard water-flow pyrheliometer. This instrument is a hollow chamber of a test-tube like form having hollow walls in which circulates in a spiral channel a current of water. The sun’s rays enter this chamber through a vestibule of constant temperature. Just before reaching the chamber they pass through a circular aperture of known area and shine upon the blackened wall at the chamber’s extreme rear. Any remnant not fully absorbed by the blackened wall is reflected to and thrown upon other parts of the chamber wall until fully absorbed. In the flowing water current, just at the mouth of the chamber, are found the arms of a platinum electrical thermometer, by means of which the rise of temperature of the water due to the heat absorbed from the sun-rays within the chamber is measured. The water which has flowed through the apparatus is collected and weighed from time to time so as to determine the rate of flow. Thus the intensity of the sun’s heat is measured in terms of the rise of temperature of a known weight of water caused by the absorption of solar rays over a known area ina giventime. In order to get a check upon the accuracy of the measurement, known quantities of electricity are caused to flow over coils within the chamber and the heat thus developed is measured, as if it were solar heat, by the flowing water. Comparisons of this instrument with other special devices for measuring solar heat have been made from time to time for the past 10 years. No change in the scale of measurement has been detected within this interval. Thus we may regard the whole body of Mount Wilson data as an homogeneous system of measurements of that fun- damental quantity, the intensity of the solar radiation available to warm the earth. Over 30 copies of the secondary so-called “silver-disk pyrhelio- meter,” figure 1, also devised for the investigation, have been prepared and standardized at the Smithsonian Institution and supplied at cost to observers over all the earth. Thus the Smithsonian standard scale of radiation measurements has become widely diffused. RESULTS ACCOMPLISHED UP TO 1910. The chief results accomplished in the research up to 1910 had been as follows: 1. The processes for determining the intensity of the sun’s radia- tion outside the earth’s atmosphere had been perfected and the whole inv Ee ucdaaes reduced to a well-organized routine. 2 A standard scale of radiation measurements had been sen lished by the invention and construction of the standard water-flow pyrheliometer. The silver-disk secondary pyrheliometer had been perfected and had proved fully satisfactory for the daily observa- tions. ’ SUN’S HEAT—ABBOT. 158 3. Several simultaneous determinations of the solar constant of radiation had been made at Washington, Mount Wilson, and Mount Whitney. No difference in the result, depending upon the elevation of the station, had been revealed, and the mean value for the solar Fie. 1.—Abbot silver disk pyrheliometer. constant of radiation of about 1.95 calories per square centimeter per minute had been obtained. This in itself was a great step for- ward, for now a reference point had been established which in future times would be available to determine the question of possible secu- lar variation in the radiant energy of the sun. 4. The results had strongly indicated the short period variability of the solar radiation. This discovery, if confirmed, bade fair to have important consequences for meteorology. 154 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 5. The distribution of energy in the solar spectrum had been closely determined, and thereby our knowledge of the sun’s temperature and nature had been materially increased. 6. Various by-products of the investigation, such as relating to the transparency of the atmosphere under different circumstances of humidity and haziness and for different altitudes from sea level up to the level of Mount Whitney, the study of the dependence of the temperature of the earth on radiation, the temperature of sun spots as compared with other parts of the sun’s disk, and many other matters, had been investigated. BASSOUR, ALGERIA. By far the most interesting of these results of the investigation was the supposed short-period variability of the sun. Although the values of the “solar constant” did not appear to depend upon the altitude of the observer above sea level, yet the apparent variations of the sun were so little greater than the probable errors of the observations that it seemed essential to strengthen the discovery of the solar variability by some other independent check. The most obvious procedure was to equip another observing station in a favor- able region far removed from Mount Wilson, and to carry on for a considerable period of time duplicate measurements of the “solar constant” at the two stations. Preparations were made to go to Mexico for this purpose, but the breaking out of revolution there made it undesirable to set up the station in Mexico. Accordingly, the expedition was diverted to Algeria, in North Africa, a country under tlhe stable government of the French, where good conditions with regard to cloudlessness might be expected. The expedition went forward in 1911, employing the same apparatus that had been used on Mount Whitney, although with decided improvements in many respects. The expedition was in charge of the writer, who was accompanied by Mrs. Abbot and assisted by Professor Brackett, of Pomona College, California. After discussion with the United States vice consul at Algiers, the director of the observatory there, and others, a site was selected at a little hamlet called Bassour, about 50 miles south of Algiers. With the exception of a few French neighbors, the people in the vicinity were all Arabs, and there was a great deal of interest in observing their customs and methods of working, which are nearly identical with those of the times of Abraham. The most important Arab in the neighborhood was a caid, who took a great interest in our work and assisted it by keeping his curious neighbors from inter- rupting it. As a boy I had sometimes wondered at the story in the Book of Ruth, which says that Boaz slept upon his threshing floor. On our farm in New Hampshire we sometimes threshed small lots of grain Smithsonian Report, 1920—Abbot, PLATE 2. |. Mr. ANGSTROM AND THE SOLAR-CONSTANT APPARATUS AT BASSOUR, ALGERIA. 2. OBSERVING STATION AT BASSOUR, ALGERIA. . | tie SUN’S HEAT—ABBOT. 155 or beans upon the floor of the great barn, and I had imagined Boaz as going out to sleep upon his barn floor and wondered why he pre- ferred doing so to sleeping in the house. Our experience in Algeria solved this mystery, for it appeared that the threshing floor was a hard level place upon the ground where Boaz slept under the light of the stars. The reason why he did so was doubtless the same that induced our French neighbor to take his double-barreled shotgun and his dog and go out and sleep on his grain pile, with the dog tied to his ankle—to prevent his neighbors from stealing the grain. Many other sights and customs reminded one continually of passages in the Bible, among them especially the driving of the oxen round and round upon the wheat to tread out the grain. As they took a mouth- ful now and then, one remembered that it says in the law: “Thou shalt not muzzle the ox when he treadeth out the corn.” Unfortunately the year 1911 proved to be a little unfavorable to the comparison of results between Algeria and California, owing to the unusual prevalence of cirrus clouds at both stations. Although the results appeared to support the view of the sun’s variability, they RP InFRA-REO a © .986 Inrra-Reo At b55e4 Biue-Green UctraMore? A«.503 A. Fic. 2.—Brightness distribution along sun’s diameter fer different colors. were not wholly conclusive and the expedition to Algeria was re- newed in June, 1912. We were still pursued by unfortunate circumstances as far as in- vestigating the variability of the sun was concerned, for the great voleanic eruption of Mount Katmai, in Alaska, which took place about June 6, filled the atmosphere of the whole northern hemisphere with volcanic dust, which spread to Algeria and California within less than three weeks after the eruption, and, growing more and more abundant, so much obscured the sun’s rays that a falling off of 20 per cent of their intensity at midday was found not unusually the case in July and August, 1912. Notwithstanding these untoward circum- stances, the results of 1912 taken in combination with those of 1911, strongly confirmed the reality of the variation of the sun—so much so that thereafter we had no doubt of the reality of this discovery. SOME DEVELOPMENTS OF THE RESEARCH IN THE INTERVAL BETWEEN THE ALGERIAN AND SOUTH AMERICAN EXPEDITIONS. The matter received a further confirmation, however, in 1913, by the introduction on Mount Wilson of the tower telescope and the investigation of the distribution of radiation over the sun’s disk. 156 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. As shown by the illustration, figure 2, the sun is not equally bright along its diameter, but falls off rapidly toward the edges of the disk. This contrast in brightness between the center and edge of the solar disk is much greater for violet and ultra-violet rays than it is for red and infra-red ones, but what is particularly interesting, the contrast of brightness which had been determined in Washing- ton in 1907 was found to be less when it was redetermined at Mount Wilson in 1913. Not only was this result found, which confirmed the existence of the variability of the sun in the term of years, but the experiments at Mount Wilson show that the contrast of bright- ness varied from day to day in association with the variations of the “solar constant.” This result, taken in connection with the experi- . ments in California and Algeria in 1911 and 1912, fully confirmed the existence of the short-period variations of the sun. VISIT TO AUSTRALIA. In most countries the seat of government is fixed at some promi- nent city, but the United States and Australia are alike in that a special place was selected to build the capital. In the United States, although the streets were well laid out, no particular care appears to have been taken in regulating the character of buildings in Wash- ington, so that, apart from the great public spaces and some fine buildings for Government purposes, the city presents the ordinary up and down happy-go-lucky appearance of almost all of the Amer- ican cities. In Australia, however, a competition was established to plan a model city for the new capital at Canberra. Amongst the in- stitutions embraced in the plan of public buildings was to be an ob- servatory. In 1914 the British Association for the Advancement of Science met in Australia. In connection with it, various scientists were invited by the Australian Government, and amongst them the writer was asked to attend and to take the opportunity to present to the Government and to Australians and others interested the story of the solar researches which have been mentioned above, in order that if possible plans might be made for the inclusion of the “solar constant” work in the program of the proposed new Government observatory at the capital city of Canberra. Accordingly, the writer -sailed to Australia in 1914, but as he arrived at Sidney came the news of the outbreak of the great Euro- pean war. Accompanied by the astronomer royal of England, Sir Oliver Lodge, the former premier of Austrdlia, and other men of ereat weight, the writer waited upon the premier at Melbourne and presented the case of the “solar constant” work as had been ex- pected. But it was felt that owing to the unexpected participation of Australia in a great war the time was unpropitious for promoting any new projects, although much interest was taken in the work de- Smithsonian Report, 1920—Abbot. |. OBSERVATORY AND COOKHOUSE, HumP MOUNTAIN, N. C. 2. A. F. MooRE REDUCING OBSERVATIONS WITH SLIDE- RULE MACHINE. PLATE Smithsonian Report, 1920—Abbot. PLATE 4. OBSERVING STATION OF ASTROPHYSICAL OBSERVATORY ON MOUNT WILSON WITH NEW TOWER TELESCOPE. Photograph by Abbot. —— Sw —E—= , SUN’S HEAT—ABBOT. 157 scribed, not only in Australia but also in New Zealand. Later on, within the last year or two, further inquiries have come from Austra- lia in regard to the work and it may be possible that even yet this kind of observing may be undertaken there. The writer felt that the regular observation of the solar radiation at several first-class cloudless stations remote from one another in different quarters of the world ought to be undertaken, now that the variation of the sun in short irregular periods had been established. This conviction was much strengthened by the painstaking work of Mr. H. Helm Clayton, chief forecaster of the Argentine Weather Service, who about 1914 began to discuss all the measurements made at Mount Wilson with a view to determine if the apparent changes in the sun appeared to be correlated with the climatic conditions of Argentina and other parts of the world. His computations from the first seemed to point to interesting correlations, so that the desirability of making a better groundwork of “solar constant” observations for the use of meteorologists was strongly indicated. SOUTH AMERICAN EXPEDITION, In 1917, Secretary Walcott, of the Smithsonian Institution, decided to employ a part of the income of the Hodgkins fund, which had been bequeathed to the Smithsonian Institution for the advancement of knowledge of atmospheric air, to promote these “solar constant” studies. The entrance of the United States into the war prevented the sending of an expedition immediately to South America as had been expected, and it was temporarily located at Hump Mountain in North Carolina. Here under the charge of Mr. A. F. Moore, assisted by Mr. L. H. Abbot, the measurements were made from June, 1917, to March, 1918. On one occasion observations were carried through successfully with an average air temperature of—5° F. Mr. Abbot froze fingers and feet in making the pyrheliometric observations on this occasion. The results of this day of work did not, however, differ from those obtained under more comfortable auspices, but still further widened the variety of circumstances which seem to have no influence on the accuracy of the resulis. In March, 1918, the expedition was removed to Calama, Chile, on the farther edge of the Atacama nitrate desert. Here it was hoped to obtain cloudlessness equal to any which could be found in the whole world. The rainfall in that region is almost nil. Calama, a city of several thousand inhabitants, is situated on the bank of the River Loa, about 10 miles from Chuquicamata where the Guggenheim Co. has a _ great copper mine, and where is collected a colony of several hundred _ Americans engaged in the mining operations, in addition to the 10,000 _ or more Chileans and Bolivians employed there. The officials of the 158 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920, mining company were very kind and helpful to the Smithsonian ex- pedition under the charge of Mr. Moore, assisted by Mr. Abbot, and placed at their disposal a building at Chorillos, near Calama, along with furniture and other equipment which materially aided in the establishment of the station. Observations were begun at Calama on July 27, 1918, and continued there for exactly two years. The station proved to be not quite so favorable as had been hoped, owing to the dust and smoke coming from the city and from the mine which occasionally interfered with the purity of the atmosphere. Nevertheless remarkably accordant and satisfactory results were obtained there. In May, 1919, the writer, with Mrs. Abbot, visited the observers at Calama, and with Mr. Moore went on to La Paz, Bolivia, where they observed the total eclipse of the sun of May 28, 1919, under extraordinary conditions. The sun rose partly eclipsed over a range of snow-covered mountains over 20,000 feet high and was observed under beautifully favorable conditions from the temporary station at an altitude of nearly 13,000 feet, at El Alto, so-called, on the rim of the tremendous canyon above the city of La Paz. Excellent photo- graphs were secured, and also measurements with the pyranometer of the brightness of the sky before and during the eclipse. On the return to Calama, Mr. Moore and the writer visited the Argentine Weather Bureau station at La Quiaca, Argentina, where they met Mr. Wiggin, chief of the Argentine Weather Service, and Mr. Clayton, chief forecaster, and discussed with them the applica- tion of solar radiation measurements to forecasting of weather. Great progress had been made by Mr. Clayton and his colleagues in the computation of the correlations between variations of the sun and variations of temperature, rainfall, etc. So much so, that Mr. Clayton and his chief had become fully convinced of the value of solar variation work as a forecasting element. Already in Decem- ber, 1919, the Argentine Weather Service had arranged with Mr. Moore, director of the Smithsonian observatory at Calama, for a daily telegraphic report of the “solar constant” value obtained at Calama. In order to furnish this daily report, Messrs. Moore and Abbot had been obliged to work with the greatest rapidity, accuracy, and devotion in the computations. Observations for determining the “solar constant” required several hours of observing, the develop- ment and washing of a photographic plate, the reading of six bolo- graphic curves at nearly 40 different places corresponding to 40 different wave lengths of radiation, and a great mass of computa- tions such as formerly used to require nearly three days altogether. Owing, however, to the introduction of a special slide-rule graphical reduction machine, the work had been greatly shortened, and further improvement was made by the use of the theodolite to determine the Smithsonian Report, 1920—Abbot. PLATE 5. |. CARNEGIE SOLAR OBSERVATORY, MOUNT WILSON, CALIF. I[60-FOooT TOWER AND 60-INCH DOME. 2. SOLAR OBSERVING STATION AT CALAMA, CHILE. SUN’S HEAT—ABBOT. . 159 altitude of the sun, and thereby the mass of air traversed by its beam, instead of to determine this by time observations as had always been the case at Mount Wilson. Nevertheless, the work of determining the “solar constant” on the same day as the observation was extremely arduous and tedious to the two observers. Their en- thusiasm was naturally extremely aroused by the favorable reports which were found in the conference of Messrs. Moore and Abbot with Messrs. Wiggin and Clayton in Argentina. On their return to Calama the writer and Mr. Moore aiscussed the possibility of determining the “solar constant” by a short method, and after a considerable computation and trial such a method was ob- tained. It depends upon the fact that the transparency of the sky is closely related to its brightness. It is easy to see that when the sky is hazy the transparency will be diminished and the brightness near the sun greatly increased. The amount of haze depends upon the humidity in the air and also upon the amount of dry dust which has been carried up by the wind, or by volcanic eruptions, or other- wise. It was possible to effect a combination of the measurements of the brightness around the sun by the pyranometer, and the humidity of the air determined by Fowle’s spectroscopic method by a single bolograph, so as to obtain a function which could give the coefficient _ of transparency with a high degree of accuracy. This short method _ was thereupon introduced at Calama and proved in extensive prac- tice to be highly satisfactory. It is possible thus to obtain the “solar constant” several times in each day, where one observation before had been all that was usual. This new method is continually checked against the older and fundamental one, and up to the present _ time has shown very satisfactory and complete agreement, except that the new method with its several observations is regarded to be the more accurate of the two. TRANSFER OF MOUNT WILSON AND CALAMA STATIONS TO BETTER SITES, Early in the year 1920 the writer had an extended conference _ verbally and by correspondence with Professor Marvin, Chief of _ the United States Weather Bureau, as to the applicability of solar _ radiation measurements for forecasting purposes in general, and in _ the United States in particular. Mr. Marvin felt that the experi- mental basis so far available from the results at Mount Wilson and at Calama was not adequate to warrant much investigation of _ this question. Feeling strongly the justice of this view; the writer _ urged upon Congress at the hearing of the Smithsonian Institution _ before the Appropriations Committee in February, 1920, that a suit- _ able appropriation should be made to erect on an isolated mountain _ in the most cloudless region of the United States a special observing 160 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. station for this work. In the then straitened condition of the Goy- ernment finances the appropriation was not made. Feeling, how- ever, the urgency of the matter, the writer arranged to lay it before Mr. John A. Roebling, of Bernardsville, New Jersey, who had already shown a great deal of interest in the work carried on by the Institution in South America. Mr. Roebling expressed the warmest appreciation of the work and suggested that there would be few found who would take so much interest as he in it, and be willing to support improvements in a foreign country, but that many would be glad to associate themselves with the proposed observing station in Arizona or southern California. However, as attempts had already been made to secure support for that new station, and as the immediate establishment of it was urgent, Mr. Roebling at length proposed to give a certain sum of money on condition that the station in Calama should be removed to a mountain site above the turbidity of the atmosphere caused by the smoke and dust of the mines of Chuquicamata and the town of Calama. Any balance remaining from the gift might then be used for the establishment of a station in Arizona or in the most favored locality, or for any other purposes which might relate to the investigation at hand. He proposed to give $8,000 toward these objects, but later generously increased this amount to $11,000. Mr. Moore was immediately tele- graphed to in regard to the removal of the station from Calama to a mountain site. Aided by his colleagues, but with his extraordinary devotion, enthusiasm, and energy, Mr. Moore was able to select a most favorable site about 10 miles farther south than the one hitherto occupied, to award contracts for the construction of the observing station and observers’ quarters, and to remove the outfit, with a loss of less than 10 observing days, from Calama to the new moun- tain station called Montezuma, where observations were resumed on August 5, 1920. The whole cost of this transfer of the observing station, under Mr. Moore’s economical management, amounted to but little more than $4,000. In his subsequent reports Mr. Moore has dwelt with ‘the utmost enthusiasm on the improvement due to the removal to Montezuma. He considers this to be, in regard to the purity of the atmosphere, the freedom from clouds, the absence of winds, the accessibility to the town, and in other respects probably the most favorable station which could be found in the whole world. Measurements are going on daily at Montezuma, sometimes by the new short method but often by the longer fundamental method as well, and it is expected to continue the work there for a period of years. Mr. Moore having been in South America for two and a half years, has now returned to the United States and will continue Smithsonian Report, 1920—Abbot. PLATE 6. |. OBSERVATORY ON MOUNT HARQUA HALA, ARIZ. 2. COELOSTAT AND PYRHELIOMETER, MOUNT HARQUA HALA. Smithsonian Report, 1920—Abbot. PLATE 7. I. MONTEZUMA SOLAR OBSERVING STATION, CHILE. COELOSTAT AND PYRHE- LIOMETRIC APPARATUS. 2. MONTEZUMA SOLAR OBSERVING STATION. THE PEAK ON WHICH THE OBSERVATORY IS LOCATED. SUN’S HEAT—ABBOT. 161 the observations in the new station in Arizona. He is succeeded as director in South America by Mr. L. H. Abbot. ARIZONA STATION, The remainder of Mr. Roebling’s gift was available to transfer the solar radiation outfit hitherto at Mount Wilson to a new locality chosen with regard to its cloudlessness on Mount Harqua Hala, Arizona. The choice of the station resulted from an investigation undertaken by the Weather Bureau through its local chief of opera- tions at Phoenix, Arizona, Mr. Fletcher. This officer made an inves- tigation of many proposed sites in California, Nevada, and Ari- zona, and at length the choice narrowed down to the vicinity of Bagdad and Cima, towns in California, and to the vicinity of Wen- den, Arizona. Special cloud observations were undertaken by observers in these localities, which after six months of observing indicated a preference for the region of Wenden, Arizona. 20’, the quan- tity (3) will vanish at a value of 7 given by r( p—20’) =b.20’, which equation appears correct within practical limits for large cir- cular pole pieces. 4Tn the figure these angles are greatly exaggerated for clearness. ee ee pe EW tS OLN EM INES the MASS SPECTRA OF THE ELEMENTS—ASTON. 229 Referred to axes OX, OY, the focus is at 7 cos (¢—20’), 7 sin (¢—26’), or 7, b.20’; so that to a first-order approximation, what- ever the fields, so long as the position of the diaphragm is fixed, the foci will all lie on the straight line ZF drawn through Z parallel to OX. For purposes of construction G the image of Z in OY is a convenient reference point, ¢ being here equal to 46. It is clear that a photographic plate, indicated by the thick line, will be in fair focus for values of e/m over a range large enough for accurate comparison of masses. The arrangement, which has a distinct resemblance to the ordi- nary quartz spectrograph, gives very complete control. The field between the plates can be adjusted to allow the brightest part of the electric spectrum to be used which, as has been shown, is in general _ the same for all normal rays under steady discharge, and the values of e/m can be compared very accurately from the positions of their lines relative to those of standard elements which can be brought to any desired position on the plate by varying the magnetic field strength. CONSTRUCTION OF THE MASS SPECTROGRAPH. THE SLITS. The very fine slits used in this apparatus were made with com- parative ease, as follows: A cylinder of pure aluminium about 10 millimeters long by 5 millimeters wide is carefully bored with a hole 1 millimeter diameter. The resulting thick-walled tube is then cleaned and crushed with a hammer on an anvil until the circular hole becomes a slit about 3 millimeters wide. Continuation of this treatment would result in a slit as fine as required, giving the maxi- * mum resistance to the passage of gas, but its great depth would make the lining up of a pair a matter of extreme difficulty. The crushed tube is therefore now placed between two V-shaped pieces of steel and further crushed between the points of the V’s at about its middle * point until the required fineness is attained. Practice shows that the best way of doing this is to crush until the walls just touch, and then to open the slit to the required width by judicious tapping at right angles to that previously employed. With a little care it is possible to make slits with beautifully parallel sides to almost any degree of fineness, 0.01 millimeter being easily attainable. At this stage the irregularly shaped piece of aluminium is not suited to accurate gas- tight fitting; it is therefore filled with hard paraffin to protect it from small particles of metal, etc., which, if entering, can not be dislodged owing to its shape, and turned up taper to fit the standard mountings. These in the present apparatus are taper holes in the back of the cathode and in a corresponding brass plug at the ends of a wide tube 230 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 10 centimeters long. When turned, the paraffin is easily removed by heat and solvents. THE DISCHARGE TUBE.® Figure 2 is a rough diagram of the present arrangement. The dis- charge tube B is an ordinary X-ray bulb 20 centimeters in diameter. . The anode A is of aluminium wire 8 millimeters thick surrounded concentrically by an insulated aluminium tube 7 millimeters wide to protect the glass walls, as in the Lodge valve. Fie. 2.—Diagram of the mass-spectroscope. The aluminium cathode C, 2.5 centimeters wide, is concave, about 8 centimeters radius of curvature, and is placed just in the neck of the bulb, this shape and position having been adopted after a short pre- liminary research. In order to protect the opposite end of the bulb, which would be immediately melted by the very concentrated beam of cathode rays, a silica bulb D, about 12 millimeters diameter, is mounted as indicated. The use of silica as an anticathode was sug- Fie. 3.—The discharge tube. gested by Professor Lindemann, and has the great advantage of cutting down the production of undesirable X rays to a minimum. The discharge is maintained by means of a large induction coil actuated by a mercury coal-gas break; about 100 to 150 watts are passed through the primary, and the bulb is arranged to take from 0.5 to 1 milliampere at potentials ranging from 20,000 to 50,0000 volts. Owing to the particular shape and position of the electrodes, especially those of the anode, the bulb acts perfectly as its own rectifier. 5 Hxtracted from ‘‘ The mass spectra of chemical elements,” Philosophical Magazine and Journal of Science, May, 1920, pp. 611-625. MASS SPECTRA OF THE ELEMENTS—ASTON. 231 The method of mounting the cathode will be readily seen from figure 8, which shows part of the apparatus in greater detail. The neck of the bulb is ground off short and cemented with wax to the flat brass collar EK, which forms the mouth of an annular space be- tween a wide outer tube F and the inner tube carrying the cathode. The concentric position of the neck is assured by three small ears of brass, not shown. ‘The wax joint is kept cool by circulating water through the copper pipe shown in section at G. The gas to be analyzed is admitted from the customary fine leak into the annular space and so to the discharge tube by means of the side tube attached to F, shown in dotted section at Q. Exhaustion is performed by a Gaede mercury pump through a similar tube on the opposite side. The reason for this arrangement is that the space behind the cathode is the only part of the discharge bulb in which the gas is not raised to an extremely high potential. If the inlet or outlet is anywhere in front of the cathode, failing special guards, the discharge is certain to strike to the pump or the gas reservoir. Such special guards have been made in the past by means of dummy cathodes in the bore of the tubes, but, notwithstanding the fact. that the gas can only reach the bulb by diffusion, the present arrangement is far more satisfactory and has the additional advantage of enabling the bulb to be dismounted by breaking one joint only. THE SLIT SYSTEM. The center of the cathode is pierced with a 3-millimeter hole, the back of which is coned out to fit one of the standard slits, S,. The back of the cathode is turned a gas-tight fit in the brass tube 2 centi- meters diameter carrying it, the other end of which bears the brass plug H, which is also coned and fitted with the second slit, S,. The two slits, which are 0.05 millimeter wide by 2 millimeters long, can be accurately adjusted parallel by means of their diffraction patterns. The space between the slits, which are about 10 centimeters apart, is kept exhausted to the highest degree by the charcoal tube I,. By this arrangement it will be seen that not only is loss of rays by col- lision and neutralization reduced to a minimum, but any serious leak of gas from the bulb to the camera is eliminated altogether. THE ELECTRIC FIELD. The spreading of the heterogeneous ribbon of rays formed by the slits into an electric spectrum takes place between two parallel flat brass surfaces, J, J,, 5 centimeters long, held 2.8 millimeters apart by glass distance pieces, the whole system being wedged immovably in the brass containing tube in the position shown. The lower sur- 232 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. face is cut from a solid cylinder fitting the tube and connected to it and earth. The upper surface is a thick brass plate, which can be raised to the desired potential by means of a set of small storage cells. In order to have the plates as near together as possible, they are sloped at 1 in 20—i. e., half the angle of slope of the mean ray of the part of the spectrum which is to be selected by the dia- phragms. Of these there are two: One, K,, an oblong aperture in a clean brass plate, is fixed just in front of the second movable one, K,, which is mounted in the bore of a carefully ground stopcock L. The function of the first diaphragm is to prevent any possibility of charged rays striking the greasy surface of the plug of the stopcock when the latter is in any working position. The variable diaphragm is in effect two square apertures sliding past each other as the plug of the stopcock is turned, the fact that they are not in the same plane being irrelevant. When the stopcock is fully open as sketched in figure 3, the angle of rays passing is a maximum and may be stopped down to any desired extent by rotation of the plug, becoming zero before any greasy surface is exposed to the rays. Incidentally the stopcock serves another and very convenient use, which is to cut off the camera from the discharge tube, so that the latter need not be filled with air each time the former is opened to change the plate. THE MAGNETIC FIELD. After leaving the diaphragms the rays pass between the pole pieces M of a large DuBois magnet of 2,500 turns. The faces of these are circular, 8 centimeters diameter, and held 3 millimeters apart by brass distance pieces. The cylindrical pole pieces themselves are soldered into a brass tube O, which forms part of the camera N. When the latter is built into position the pole pieces are drawn by screwed bolts into the arms of the magnet, and so form a structure of great weight and rigidity and provide an admirable foundation for the whole apparatus. Current for the magnet is provided by a special set of large accumulators. The hydrogen lines are brought onto the plate at about 0.2 ampere, and an increase to 5 amperes, which gives practical saturation, only just brings the singly charged mercury lines into view. The discharge is protected from the strong field of the magnet by the usual soft iron plates, not shown. THE CAMERA. The main body of the camera N is made of stout brass tube 6.4 centimeters diameter, shaped to fit onto the transverse tube O con- taining the pole pieces. The construction of the plate holder is in- dicated by the side view in figure 2 and an end-on view in figure 4. MASS SPECTRA OF THE ELEMENTS—ASTON. 233 The rays, after being magnetically deflected, pass between two ver- tical brass plates, Z Z, about 3 millimeters apart, and finally reach the photographic plate through a narrow slot 2 millimeters wide, 11.8 centimeters long, cut in the horizontal metal plate, X X. The three brass plates forming a T-shaped girder are adjusted and locked in position by a set of three leveling screws at each end; the right- hand upper one is omitted in figure 4. The plates, Z Z, serve to pro- tect the rays completely from any stray electric field, even that caused by the photographic plate itself becoming charged, until within a few millimeters of their point of impact. The photographic plate W, which is a 2-centimeter strip cut lengthwise from a 5 by 4 plate, is supported at its ends on two narrow transverse rails which raise it just clear of the plate, X X. Normally it lies to the right of the slot as indicated, and to make an exposure it is moved parallel to itself over the slot by means of a sort of double lazy tongs carrying wire claws, which bracket the ends of the plate as shown. 'This mecha- nism, which is not shown in detail, is op- erated by means of a torque rod V work- ing through a ground glass joint. Y isa small willemite screen. The adjustment of the plate holder so that the sensitized surface should be at the best focal plane was done by taking a series of exposures of the bright hy- drogen lines with different magnetic fields, on a large plate placed in the empty camera at a small inclination to the vertical. On de- veloping this the actual track of the rays could be seen and the locus of points of maximum concentration determined. The final adjust- ment was made by trial and error and was exceedingly tedious, as air had to be admitted and a new plate inserted after each tentative small alteration of the leveling screws. Fic. 4.—The camera, EXPERIMENTAL PROCEDURE. The plate having been dried in a high vacuum over night, the whole apparatus is exhausted as completely as possible by the pump, with the stopcock L open. I, and I, are then cut off from the pump by stopcocks and immersed in liquid air for an hour or so. The electric field, which may range from 200 to 500 volts, is then applied and a smal] current passed through the magnet sufficient to bring the bright hydrogen molecule spot onto the willemite screen Y, where 234 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. it can be inspected through the plate-glass back of the cap P. In the meantime the leak, pump, and coil have all been started to get the bulb into the desired state. As soon as this is obtained and has become steady, J, is earthed to prevent any rays reaching the camera when the plate is moved over the slot to its first position, which is judged by inspection through P with a nonactinic lamp. The magnet current having been set to the particular value desired and the diaphragm adjusted, the coil is momentarily interrupted while J, is raised to the desired potential, after which the exposure starts. During this, preferably both at the beginning and the end, light from a lamp T is admitted for a few sec- onds down the tube R (fig. 2), the ends of which are pierced with two tiny circular holes. The lower hole is very close to the plate, so that a circular dot or register spot is formed from which the measure- ments of the lines may be made. The exposures may range from 20 seconds in the case of hydrogen lines to 30 minutes or more, 15 minutes being usually enough. As soon as it is complete the above procedure is repeated, and the plate moved into the second position. In this way as many as six spectra can be taken on one plate, after which Lis shut, I, warmed up, and air admitted to the camera. The cap P, which is on a ground joint, can now be removed and the exposed plate seized and taken out with a special pair of forceps. A fresh plate is now immediately put in, P replaced, and the camera again exhausted, in which state it is left till the next operation. * * * The accuracy claimed for the instru- ment is about one part in a thousand. ORDER OF RESULTS AND NOMENCLATURE. The various elements studied will be considered as far as possible in the order in which the experiments were performed. This order is of considerable importance, as in most cases it was impossible to eliminate any element used before the following one was introduced. Evacuation and washing have little effect, as the gases appear to get embedded in the surface of the discharge bulb and are only released very gradually by subsequent discharge. : The problem of nomenclature became serious when the very com- plex nature of the heavy elements was apparent. After several pos- sible systems had been discussed it was decided, for the present, to adopt the rather clumsy but definite and elastic one of using the chemical symbol of the mixed element with an index corresponding to its mass—e. g., Ne®*, Kr®*.. This system is made reasonable by the fact that the masses of constituents of mixed elements have all so far proved whole numbers on the scale used. In cases of particles carrying more than one charge it will be con- venient to borrow the nomenclature of optics and refer to the lines *| aLlwd "u0JSY—OZEL ‘HOdey uBlUOsYyWS a tO a i i, ee MASS SPECTRA OF THE ELEMENTS—ASTON. 935 given by singly, doubly, and multiply charged particles, respectively, as lines of the first, second, and higher orders. Thus the molecule of oxygen gives a first order line at 32, and its atom first and second order lines at 16 and 8. The empirical rule that molecules only give first-order lines (J. J. Thomson, Rays of Positive Electricity, p. 54) is very useful in help- ing to differentiate between elementary atoms and compound mole- cules of the same mass. Some very recent results give indications that in certain exceptional cases it may break down, so that inferences made from it must not be taken as being absolutely conclusive. OXYGEN (AT. WT. 16.00) AND CARBON (AT. WT. 12.00). On a mass spectrum all measurements are relative, and so any known element could be taken as a standard. Oxygen is naturally selected. Its molecule, singly-charged atom, and doubly-charged atom give reference lines at 32, 16, and 8, respectively. The ex- tremely exact integral relation between the atomic weights of oxygen and carbon is itself strong evidence that both are “ pure” elements, and so far no evidence appears to have arisen to throw any doubt on this point. Direct comparison of the C line (12) and the CO line (28) with the above standards shows that the expected whole number relation and additive law hold to the limit of accuracy, i. e., one part in a thousand; and this provides standards C* (6), C (12), CO (28), and CO, (44). In a similar manner, hydrocarbons give the C, and C, groups already mentioned (Phil. Mag., April, 1920, pp. 452, 453) so that a fairly complete scale of reference is immediately available. NEON (AT. WT. 20.20). The results obtained with this gas have already been fully dealt with (Phil. Mag., April, 1920, p. 449). It has been shown to con- sist of two isotopes of masses 20 and 22, respectively, with the faint possibility of a third of mass 21. Spectrum I on plate 1 shows the singly charged lines of neon, to the left of the C, group. It is reproduced here to show the condition of the discharge tube im- mediately before compounds of chlorine were introduced. CHLORINE (AT. WT. 35.46). Spectra, indicating that this element was a mixture of isotopes, were first obtained by the use of hydrochloric acid gas, but as this was objectionable, on account of its action on mercury, phosgene (COCI,) was substituted. Spectra II, III, and IV are reproduced from one of the plates taken with this gas. It will be seen that 236 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. chlorine is characterized by the appearance of four very definite lines in the previously unoccupied space to the right of O, (32): Measurement shows these lines to correspond exactly to masses 35, 36, 87, and 38. TLhere is no indication whatever of a line at a point cor- responding with the accepted atomic weight of 35.46. On Spectrum II, taken with a small magnetic field, faint lines will be seen at 17.5 and 18.5. These only appeared when chlorine was introduced, and are certainly second-order lines corresponding to 35 and 37. These figures seem to leave no possible escape from the conclusion that chlorine is a mixture of isotopes and that two of these have masses 35 and 37. It might be argued that 36 and 38 are also elementary lines, and at present there is no evidence to deny this, but it is much more probable that they are the hydrochloric acids HCl and HCl’. The line 18 is no indication of an element 36, as it is doubt- less due to OH,. Corroborative evidence that Cl®* and Cl*’ are the main, if not the only, constituents is given by the strong lines 63 and 65 (Spectrum IV), probably due to COCI® and COCI?". If chemical atomic weight is regarded as a statistical average, any lines due to Cl** or its compounds should be considerably stronger than the corresponding one due to Cl*’.. This is actually found to be the case. In all spectra taken with chlorine present a faint line is distinguishable, corresponding to 39. It is just possible that this is a third isotope. The unquestionable accuracy of its combining weight on the one hand, and the striking whole-number masses given on its mass spectra by its individual particles on the other, leave little doubt that chlorine is a mixed element; but much critical work will be necessary before its constituents and their relative proportions are decided with certainty. ARGON (AT. WT. 39.88 RAMSAY, 39.91 LEDUC). At the close of the experiments with phosgene the discharge tube broke down and had to be cleaned and partially rebuilt, so that by the time it had reached suitable working conditions again, all traces of chlorine had disappeared. The tube was run with a mixture of CO, and CH,, and then about 20 per cent of argon added. The main constituent of the element was at once evident from a very strong line at 40 (Spectrum VI), reproduced in the second and third orders at 20 and 13.33 (Spectrum V). The third-order line is exceedingly well placed for measurement, and from it the mass of the singly charged atom is found to be 40.00+.02. At first this was thought to be the only constituent, but later a faint companion was seen at 36, which further spectra showed to bear a very definite intensity rela- tion to the 40 line. No evidence drawn from multiple charges is aca Se ete ei PRAT eS MASS SPECTRA OF THE ELEMENTS—ASTON. 237 available in this case, owing to the probable presence of OH, and C; but the above intensity relation and the absence of the line from spectra, taken just before argon was introduced, make it extremely likely that it is a true isotope. The presence of about 3 per cent _would account for the fractional atomic weight determined from the density. NITROGEN (AT. WT. 14.01). This element shows no abnormal] characteristics; its atom can not be distinguished, on the present apparatus, from CH,, nor its mole- cule from CO. Its second-order line, on careful measurement, ap- pears to be exactly 7, so it is evidently a pure element, as its chemical combining weight would lead one to expect. HYDROGEN (AT. WT. 1.008) AND HELIUM (AT. WT. 3.99). The determination of masses so far removed as these from the refer- ence lines offers peculiar difficulties, but as the lines were expected to approximate to the terms of the geometrical progression 1, 2, 4, 8, etc., the higher terms of which are known, a special method was adopted by which a two to one relation could be tested with some exactness. Two sets of accumulators were selected, each giving very nearly the same potential of about 250 volts. The potentials were then made exactly equal by means of a subsidiary cell and a current-divider, the equality being tested to well within 1 in 1,000 by means of a null instrument. If exposures are made with such potentials applied to the electric plates first in parallel and then in series, the magnetic field being kept constant, all masses having an exact 2 to 1 relation will be brought into coincidence on the plate. (Phil. Mag., April, 1920, p. 453.) Such coincidences can not be detected on the same spectrum photographi- cally ; but if we first add and then subtract a small potential from one of the large potentials, two lines will be obtained which closely bracket the third. To take an actual instance—with a constant current in the magnet of 0.2 ampere, three exposures were made with a gas contain- ing hydrogen and helium at potentials of 250, 500+12, and 500—12 volts, respectively. The hydrogen molecule line was found symmetri- cally bracketed by a pair of atomic lines (Spectrum VII a@ and ¢), showing that the mass of the molecule is exactly double the mass of the atom within experimental error. When after a suitable increase of the magnetic field the same procedure was applied to the helium line and that of the hydrogen molecule, the bracket was no longer sym- metrical (Spectrum VII, 6), nor was it when the hydrogen molecule was bracketed by two helium lines (d). Both results show in an un- mistakable manner that the mass of He is less than twice that of H,. 238 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. In the same way He was compared with O**, and H,, obtained from KOH by Sir J. J. Thomson’s bombardment method, with C*. The method has some definite advantages and some disadvantages. It is not proposed to discuss these in detail at present. The values obtained by its use can be checked in the ordinary way by comparing He with C** and H, with He, these pairs being close enough together for the purpose. The following table gives the range of values ob- tained from the most reliable plates: Line. Method. Mass assumed.| Mass deduced. He Bracket....... OFFS. 2s . 99 fe bets See Direct 2 - Yao G+FS6 Skee 4. 005-4. 010 H {Piece cacmeee C++=6...-... 3. 025-3. 027 Se sicine'n\elsicis.= Direct <).23 7. Fe == 4e . s 3. 021-3. 030 losses acasoen Bracket....... He =455"- 25 2. 012-2, 018 From these figures it is safe to conclude that hydrogen is a “ pure” element and that its atomic weight, determined with such consistency and accuracy by chemical methods (1.008), is the true mass of its atom. The above results incidentally appear to settle the nature of the molecule H, beyond doubt. KRYPTON (AT. WT. 82.92) AND XENON (AT, WT. 130.2). The results with these elements were particularly interesting. The only source available, for which the author is indebted to Sir J. J. Thomson, was the remains of two small samples of gas from evapo- rated liquid air kindly supplied by Sir James Dewar some years ago for examination by the “ parabola” method. Both samples contained nitrogen, oxygen, argon, and krypton, but xenon was only detected in one and its percentage in that must have been quite minute. Krypton is characterized by a remarkable group of five strong lines at 80, 82, 83, 84, 86, and a faint sixth at 78. This group or cluster of isotopes is beautifully reproduced with the same relative values of intensity in the second, and fainter still in the third order. These multiply-charged clusters give most reliable values of mass, as the second order can be compared with A (40) and the third with CO or N, (28) with the highest accuracy. It will be noted that one member of each group is obliterated by the reference line, but not the same one. The singly and doubly charged krypton clusters can be seen to the right and left of Spectrum VIII. It will be noticed that krypton is the first element examined which shows unmistakable isotopes differing by one unit only. On the krypton plates taken with the greatest magnetic field faint but unmistakable indications of lines in the region of 130 couid just MASS SPECTRA OF THE ELEMENTS—ASTON. 239 be detected. The richest sample was therefore fractionated over liquid air, and the last fraction, a few cubic. millimeters, was just sufficient to produce the xenon lines in an unmistakable manner. These can be seen on Spectrum IX, but are somewhat fuzzy owing to the wide diaphragm used to get maximum intensity. They are apparently five in number and appear to follow the integer rule. Until pure xenon is available no final figures can be given, but the values may be taken provisionally as 128, 130, 131, 183, and 135. MERCURY (AT. WT. 200.6). Owing to the presence of mercury vapor (which is generally bene- ficial to the smooth running of the discharge) the multiply-charged particles of this element appear on nearly all the plates taken. They appear as a series of blurred clusters of decreasing intensity around points corresponding to 200, 100, 66.6, 50 * * * etc., some of which are indicated in the spectra reproduced. It may be stated provisionally that they indicate a strong component 202, a weak one 204, and a strong band from 197 to 200 containing three or four more unresolvable at present. Table of results obtained to December, 1920. Minimum Atomic | Atomic | number | Masses of isotopes in order of their Element. Symbol. | number.| weight. | of iso- intensity. | topes. Pieyvaropen We. 4.42-255-- 15 iene a, SS 1 1,008 1 | 1.008. LITT Ma i eel ss Est Aiea 2 3. 990 1} 4. ones ss. S202. ch. 5.5 1 5 A | 5 10. 900 2 PTT; 10; WERE DOM coos conics ccc ses [ee eee 6 12. 000 Ea: MWigmmren> = Fo... Fo. Nee oe aed 7 14.010 1 | 14. Omyrane. 687 2229. 2 O2rae ek 8 16. 000 1} 16. “QU os on i or Le eee ae 9 19. 000 1/19. NOT eee wee eee Nev. 2-] 10 20. 200 2 | 20, 22 (21). SIT SS Se oe eee ee Sizieees 22 14 28. 300 2 | 28, 29 (30). Phosphorus 523221... i Saye alee 15 31. 040 13st. Ripe 28 og > ag 22 Sia ete we 16 32. 060 1 }.32. iterme. 24 0) ie 0 Di i | 17 35. 460 2 | 35, 37 (39). ATOON Sno dan bcceuad Bid jn ok ante 18 39. 880 2 | 40, 36. Meraeric: £%% . 222th. 222 Agi itt..s 74. 960 1 Ltt 0 a i 15) er eee 35 79. 920 2 | 79, 81. Kevypten sso ee, Kreis 0. 36] 82.920 6 | 84, 86, 82, 83, 80, 78. Minette eee, i ce TS age ee 53 | 126. 920 i LO at b.7 SOT Gls Ss ae irae 2 Spee OS Se 54 | 130.320 5, (7) | 129, 182, 131, 134, 136 (128, 130z). IMGECHE yg sses oo 3S) ee Hp oes 80 | 200.600 (6) | (197-200), 202, 204. (Numbers in parentheses are provisional only.) THE WHOLE-NUMBER RULE. The most important generalization yielded by these experiments is the remarkable fact that (with the exception of H,, H,, and H,) all masses, atomic or molecular, element or compound, so far meas- ured, are whole numbers within the accuracy of experiment. It is naturally premature to state that this relation is true for all elements, 240 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. but the number and variety of those already exhibiting it makes the probability of this extremely high. On the other hand, it must not be supposed that this would imply that the whole-number rule holds with mathematical exactness, but only that the approximation is of a higher order than that exhib- ited by the ordinary chemical combining weights and is quite close enough to allow of a theory of atomic structure far simpler than those put forward in the past; for such theories were forced to attempt the explanation of fractions which now appear to be merely fortuitous statistical effects, due to the relative quantities of the isotopic constituents. Thus, one may now suppose that an elementary atom of mass m may be thanged to one of mass m-++1 by the addition of a positive particle and an electron. If both enter the nucleus, an isotope results, for the nuclear charge is unaltered. If the positive particle only enters the nucleus, an element of next higher atomic number is formed. In cases where both forms of addition give a stable con- figuration the two elements will be isobares. The electromagnetic theory of mass asserts that mass is not gen- erally additive, but only becomes so when the charges are rela- tively distant from each other. This is certainly the case when the molecules H, and H, are formed from H,, so that their masses will be two and three times the mass of H, with great exactness. (It must be remembered here that the masses given by these experiments are those of positively charged particles, H, being presumably a single particle of positive electricity itself, and that the mass of an electron on the scale used is 0.00054, and too small to affect the results. ) In the case of helium, the standard oxygen, and all other elements, this is no longer the case; for the nuclei of these are composed of particles and electrons packed exceedingly close together. The mass of these structures will not be exactly the sum of the masses of their constituents, but probably less, so that the unit of mass on the scale chosen will be less than that of a single hydrogen atom. . VITAMINS.* By W. D. HALiipurTon, London, Kings College, Physiological Laboratory. The word “vitamin” is not as old as the present century, and though it is not altogether a satisfactory term, it has obtained a permanent footing in scientific and medicai literature. The expres- sion “accessory food factor,’ which has been suggested as a sub- stitute, is certainly more cumbersome. But, after all, it is a matter cf small moment what word is used; the important point is what it connotes. It is a matter of everyday physiological knowledge that our bodies are built out of proteins, fats, carbohydrates, salts, and water, and these substances must be present in the food in certain proportions and in sufficient quantities to repair the body waste and furnish the energy necessary for its activities. But recent research has shown that these substances alone are incapable of maintaining life. Some- thing else is required, the chemical nature of which is at present un- known, and it is to these unknown but indispensable accessory sub- stances that the term “vitamins” has been applied. Prof. F. G. Hopkins, of Cambridge, a pioneer in this branch of research, has suggested a useful simile to help us to understand the problem. He compares the building of the body to the building of a house. The essential bricks or blocks of stone of which the walls of the house are composed would be of comparatively little use unless cement were also supplied to unite these components together, and it is the cementing material which he compares to the vitamins. It would be dangerous to press such an analogy too far, for the exact role of the vitamins is still hidden from us. But the simile is a use- ful one to indicate one way at least in which they can render the im- portant building stones of real service, and it is accurate in a quanti- tative sense. The cement in the walls of a house makes up but a small proportion of the structure. It is exactly the same in the case 1 Reprinted by permission from “ Scientia,’ vol. XXVII. 1920. 42803 °—22 16 241 ‘ 242 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. of the vitamins, They bear but a small proportion to the total food supply. When they are withheld from the food, as when chemically pure proteins, fats, carbohydrates, salts, and water are adminis- tered, health deteriorates, and in young animals growth ceases, and if the diet is continued death is the inevitable result. Health can be at once reestablished if the diet is amplified by adding to it a natural food, such as a small amount of milk, for foods as they occur in nature contain the accessory factors necessary for growth and mainte- nance. This consideration is of practical importance to the public generally; so many are the treated, “ purified,’ and sophisticated foods at present on the market that it is most important to the dietitian to remember that these are but poor substitutes for the foods which are made in nature’s laboratory. Although biochemists have not yet got so far as to be able to state what is the chemical structure of these vitamins, research has at any rate progressed far enough to make it certain that they are numerous, and it is around three that research has mainly centered. They are products of the plant world, and it is on plants that all animals ulti- mately live. Animals have greater synthetic powers than were for- merly believed to be the case, but so far as is at present known they are not able to synthesize or manufacture vitamins. The vitamins can be separated by their varying solubilities in water and other agents, and can be distinguished by their varying powers of resistance to heat and other drastic agencies, and further they are differently distributed in various parts of the vegetable world. Their absence prevents healthy growth and leads to death, but the symptoms manifested are different in the three cases. The diseases due to their absence are very conveniently grouped together as “deficiency diseases.” Among such diseases are beriberi, and coming nearer home, scurvy and rickets. The first of these vitamins is contained in the embryo or germ of cereal seeds. When milling is carried to a high degree this portion of the grain is removed—hence, polished rice, and superfine white wheat flour, though they may appeal to the esthetic sense, are of inferior value as foods. It is now firmly established that beriberi, the disease of the rice-eating nations, is due to the use of polished rice, and can be prevented or cured by adding the polishings to the diet. Polished rice produces the disease not because it contains a poison, but because it lacks the vitamin. Using the noncommittal nomenclature intro- duced by American physiologists, it is now usual to speak of this vitamin, on account of its solubility in water, as “ Water Soluble By? The second is contained in the majority of animal fats (commercial lard is an exception), and is particularly abundant in milk fats and in certain fish oils, such as cod-liver oil. It is specially important as a VITAMINS—HALLIBURTON. 243 growth factor, and therefore indispensable in early life. It is absent in most vegetable fats. Here we have one indication of the value of milk for the young, an explanation of the potency of cod-liver oil in curing malnutrition, and a warning of the danger of vegetable margarines if employed as the only source of fat in the food of the growing sec- tion of the population or of expectant mothers. It is usual to call this vitamin “Fat Soluble A.” There is accumulating evidence to show that its absence or deficiency is an etiological factor in rickets. Like its water-soluble companion, it is ultimately a vegetable product, being contained in high concentration in the green portions of plants. It is because the cow lives on grass that her milk contains the vita- min. In expectant mothers, either milk itself or green vegetables should form important constituents of their diet, but in the feeding of infants green vegetables are for other reasons not suitable, so that in times of stress and shortage children must be provided with milk even if everyone else has to be content with little or none. In the adult the need for “ Fat Soluble A” is not so great as in the child, but it has been established that small quantities are necessary, espe- cially in periods where excessive work leads to a greater demand for nutritive principles, for instance, in our fighting forces on active service. The third vitamin is also soluble in water, and as Doctor Drum- mond suggests it may be called “ Water Soluble C.” This is the anti- scorbutic principle, and is found in the juices of fruits (the orange and lemon are here preeminent) and in most edible vegetables. Among a seagoing people like the English, scurvy was but too fa- miliar in the past, and in the sixteenth and seventeenth centuries it was a dread and terrible scourge. The remedy, fresh meat and vege- tables, was well known, but no means existed then for providing ships with these desirable commodities on their slow and protracted voyages. Scurvy also was common among the civilian population, owing no doubt to the scanty allowance of meat and especially of green vegetables available for the poorer classes. Thanks to the increased rapidity of transport and the improved facilities for the provision of fresh vegetables and fruit, adult scurvy has become much less familiar in our days, except in cases of long-continued absence from centers of civilization, such as arise in polar expeditions or under the strenuous conditions of modern warfare. In more recent times the failure of the potato crop in Ireland in 1847 was followed by outbursts of scurvy, as was also the case in Norway in 1904, and the recent failure of the fruit crop in 1917 was marked by outbreaks in Glasgow, Manchester, and Newcastle. In time of war scurvy fre- quently occurs, and numerous instances of this have occurred during the past four years, for example at Kut during the siege. In fact, a considerable proportion of the population are never far removed 244 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. from the safety line, and this is especially the case with artificially fed children, and scurvy, incipient or declared, is an ever-present danger, especially in the first years of life. This vitamin is characterized by its extreme lability, being destroyed by moderately high temperatures in the presence of oxygen, treatment with alkali, by desiccation, canning processes, and the like. The effect of cooking on the antiscorbutic vitamin seriously diminishes the amount present. But the discovery has been made, and proved invaluable during the last war, that canned cereals re- cover their antiscorbutic potency by being allowed to germinate. The high value of various citrus fruits has long been appreciated, and for the last century and a quarter reliance has been placed in the Navy and mercantile marine on lime juice as a preventive. Here the researches of Miss Chick and her colleagues on the experi- mental, and Mrs, Henderson Smith on the historical, side have re- vealed a very curious state of affairs. Modern lime juice is made from the West Indian lime, whereas the lime juice of the past was made either from the lemon or the sweet lime of Mediterranean countries. This juice was highly potent, and it was by its use that the Navy was freed from the terrible scourge which had previously devastated it. Curiously enough, although the sour lime of the West Indies is such a near relation botanically of the lemon, its value as an antiscorbutic is almost negligible. Prominent among the anti- scorbutics upon which reliance was placed by old-time seamen were beer and infusion of malt, as will be familiar to the reader of Captain Cook’s Voyages, but an investigation of modern beers and of the malt from which they are prepared has shown that they are de- ficient in the antiscorbutic factor. The difference between the old and modern beer is no doubt due to the high temperature employed in various steps of the manufacture of the latter. It will thus be seen that the subject of vitamins is of the highest importance, but we must remember that it is at present in its in- fancy. It is, perhaps, not going too far to state that the conception bids fair to have as far-reaching results as those which have followed the study of internal secretions and hormones. To label a disease by a specific name—beriberi, rickets, ete—and to fathom its cause and lead up to a rational and successful treatment of the same is no mean accomplishment, but there are many ailments to which it is impossible to give a name, so vague and puzzling are the symptoms they exhibit. It is probable that many so-called minor conditions of malnutrition may be due to lack of vitamins or to a deficiency in their supply. Although at present three vitamins have been brought into the light of investigation, who can say that the list is complete? It is more than probable that obscure and apparently trivial complaints VITAMINS—HALLIBURTON. 245 may in the future be found to be deficiency diseases. An obvious state of malnutrition in an infant may pass away, and yet it may leave its mark behind it and cause far-reaching results later in life. Take, for example, that curse of modern days, dental caries. Already, as Mrs. Mellanby has shown, there are signs that this is just such a condition, and that its cause is probably a deficiency (earlier in life) of a proper vitamin supply. Happily, many workers are taking up the subject and exploring the numerous by-paths that the main idea has opened up. Important work of this nature is that by Lieut. Col. R. McCarrison, and his paper has appeared in last year’s January number of the Indian Journal of Medical Research. The disease in particular which he dealt with is beriberi, a complaint which can be produced easily in birds by withholding water-soluble B, or, in other words, by feeding upon highly milled cereal grains. So far, the nervous symptoms of this disease, spoken of as “neuritic,” have attracted most attention, but McCarrison has shown that the condition is more than a functional and degenerative condition of the nervous system; that it is one in which practically every organ and tissue of the body is involved. The organs of digestion and assimilation are particu- larly affected, and thus many of the symptoms are due to the chronic inanition so produced. The lowered vitality then renders the body an easy prey to infectious and parasitic agents, and thus other symp- toms become explicable. Among the many remarkable results chronicled is that while the adrenals hypertrophy, there are other organs which atrophy, and in order of severity these are the thymus, testes, spleen, ovary, pancreas, heart, liver, kidneys, stomach, thy- roid, and the brain least. It therefore appears that the organs which atrophy provide a reserve of vitamins for use in periods of stress, but that the reserve is soon exhausted. One disease, namely, pellagra, I have not mentioned, and it is of particular interest to Italians. Conflicting views are at present held as to its causation, many regarding it as an infectious ailment, whereas others look upon it as a deficiency disease. It is the condi- tion which follows the effects of maize feeding. The maize protein, as is well known, is an imperfect one, and lacks many of the im- portant amino-acids which are needed for tissue building. It may be that the deficiency is in the protein. Still it is quite possible that here also we may have to deal with the lack of a specific vitamin. This view at any rate has been taken by Rondoni, who has published a recent paper in the British Medical Journal, 1919, I, page 542, in which he compares his experimental results on guinea pigs with those of McCarrison on birds. Here also there is an enlargement of the adrenals and an atrophy of certain other organs. Rondoni points 246 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. out that these results of his were published some years ago in an Italian journal, but have been overlooked by those in this country. One can only hope that in the future, in view of the friendship be- tween the countries now cemented on the recent battlefields, that such accidents will not occur again. The foregoing article has dealt only with the outline and with the more recent work upon a subject of large and increasing importance. The field is a fruitful one, and one can only trust that with fresh spade work by other workers our knowledge in this direction may be amplified and thus rendered of even greater benefit to mankind. SOIL ACIDITY—ITS NATURE, MEASUREMENT, AND RELATION TO PLANT DISTRIBUTION. By Epear T. WHERRY, United States Bureau of Chemistry. [With 2 plates.] INTRODUCTION. The studies described in the essays of which abstracts are here brought together belong in a border-line class between well-defined sciences; they represent the application of certain principles and methods of chemistry, of physics, and of geology, to the solution of problems in botany, in plant ecology, and incidentally in horticul- ture. It has been the aim of the writer to sum up in relatively simple language the principles of physical chemistry which bear on soil acidity; to develop a method for measuring soil acidity in the field; and to apply this method to the study of the distribution and the cultivation of native plants. SOIL ACIDITY.” According to the almost universally accepted electrolytic-dissocia- tion or ionization theory, many chemical compounds, under certain conditions, exhibit dissociation into electrically charged portions, known as ions. These may consist of single atoms or of groups of atoms. Only ionization connected with the dissolving of substances in water need concern us here. Compounds differ widely in the ex- tent to which they are dissociated or ionized in dilute aqueous solu- tion. Among inorganic compounds—acids, bases, and salts—many are almost completely, others only partially, ionized. Of organic compounds a few, especially acids, are markedly, a considerable num- ber slightly, and many not appreciably ionized. Water itself dissociates into hydrogen-ion, made up of positively charged hydrogen atoms, and accordingly symbolized by H+; and hydroxyl-ion, made up of negatively charged hydroxy! (hydrogen 1The field work on which these essays are based has been carried on largely at the writer’s own expense, during vacation periods, but funds for certain of the trips were ob- tained from the Bureau of Plant Industry, through Mr. Frederick V. Coville, botanist of the Department of Agriculture. It is a pleasure to acknowledge herewith the aid received in the preparation of. these papers from Mr. Coville, Dr. E. Q. Adams of the Bureau of Chemistry, and other colleagues. 2 Abstracted from an essay entitled “ Soil acidity and a field method fér its measure- ment.”’ Ecology, 1, 160-173, 1920. 247 248 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. plus oxygen) groups, symbolized by (OH)-. Acids yield hydrogen- ion and another ion consisting of the balance of their constituents; thus from nitric acid, HNO,, arise H* and (NO,)-, the latter being termed nitrate-ion. Alkalies yield hydroxyl-ion and another con- sisting of the remainder of the compounds; in potassium hydroxide, KOH, the ions are (OH)- and potassium-ion, K*. The amount of hydrogen-ion present in a solution, expressed as gram equivalents per liter, is often referred to as the hydrogen-ion concentration. The water existing in soils, as a film around the solid soil particles, does not differ essentially from free water in the above respects. Substances can dissolve in it, undergo ionization, and give rise to a definite hydrogen-ion concentration of the soil. This is what is meant by the term “soil acidity.” Observation has shown that the properties of substances which lead to their classification as acids are directly connected with the presence of hydrogen-ion in their solutions. The characteristic sour taste—from which the term acid was of course originally derived— is in considerable part the taste of hydrogen-ion.2 Reddening of blue litmus, the most widely known test for acidity, is produced by hydrogen-ion. And it is hydrogen-ion which takes part in most of the chemical changes into which acids enter. The inhibiting effect of acids on the growth of many bacteria, and the favorable effect they show toward the growth of some molds and fungi, are hydrogen-ion phenomena. There is every reason to sup- pose that the action of acids on higher organisms, such as the flower- ing plants, is identical in origin. It is evident from these considera- tions that the hydrogen-ion concentration is a highly important fea- ture of the solution of any acid substance. The difference between hydrogen-ion concentration and quantity of acid in the case of two typical acids is here tabulated. The numerical values given are only approximate. Tarte 1.—Difference between hydrogen-ion concentration and quantity of acid in normal solutions of two acids. Acid. Hydrochlo- y a Formic. Wop a - as beraet= «He cRrateeinas sence eas « Sea-aela ia ae gee aia s atone tone one HCl. | H(CHO:), Molecular weight= equivalent weight=grams per liter in normal (molar) solution 36. 5 46.0 Quantity of acidic hydrogen, grams per liter..............--.-.------------------ 1 1 Physicochemirali class’). .¢ : subsea. 13S. gine VL eee Bea. 30 Strong. Weak. Per conto which sonized njcc oo seas eeeeretese Seep nnidep ae et OE ee epee 75 ul Corresponding hydrogen-ion concentration, grams per liter............------.+-- 0.75 0.01 Specific acidity ¢................ eP oee AS SU at SEO SOS Se Poe * '7, 500, 000 100, 000 a This method of stating acidity has been explained in: The statement of acidity and alkalinity, with special reference to soils, Journ. Wash. Acad. Sci., 9, 305-309, 1919. 2 Harvey, R. B., Journ. Amer. Chem. Soc., 42, 712, 1920. Ff ce aes nn EAN SOIL ACIDITY—WHERRY. 249 Table 1 shows that although a normal (molar) solution of both acids contains the same quantity of acidic hydrogen, the strong acid yields seventy-five times as much hydrogen-ion as does the moderately weak one, and may be expected to have seventy-five times as much effect in the directions listed in the preceding paragraph. The situation is analogous to that of two men, both possessing $100, but one having $25 in a savings bank and $75 in his pocket, the other having $99 and $1 in these respective places. The first man can pur- chase seventy-five times the amount of any commodity that the second can, even though the total quantity of money they own is the same. Purchasing power, in this illustration, corresponds exactly to hydro- gen-ion concentration; for the amount of hydrogen which is ionized, not the total amount, determines most of the things an acid can do. Several different methods of stating acidity are in use, and in Table 2 the way two values selected at random appear under all of them is brought out; and the reader may judge whether the one chosen for use in the present paper (the last one tabulated, specific acidity) is not the best from the point of view of clearness and con- venience. The hydrogen-ion concentrations of the two solutions, in gram equivalents per liter, are 0.0004 and 0.0000002, respectively, the former representing two thousand times as much hydrogen-ion as the latter. TABLE 2.—Comparison of methods of stating acidity (hydrogen-ion). Solution 1. ; Solution 2. Starting at normality: ges ted onl A cits | tii Pers hc/4: See = ess Jose ee PRA SRRS RERL 0. 0004 0. 0000002 Power ot nu ee [PACES DIAS CET Re ns ge, ae On ee ie Ser a pe 0. 4X 10-5 0.210% ERMC OLE Ft ctrnst eee eel beh thie SEM pee. Sadek Me tee ieee ss 1073-4 10-6-7 Potential re ti 2 a Go) Ge he 2 SO ne ey i nn aes ie eee ree 3.4 6.7 Starting at neutrality: Cienneab parental, Sort... 223 SOs Seo sii fhe 5. 1a set eek. 255. Soa 3.6 0.3 Concentration— EWES OLMOS sane t Stk eee. eek eg ete ccte se tes oceetecwes. as are. 103-8 109-8 Actusilnom ber (specific acidity) :< 2. 5-6 otemn\- cee ele oc obiawer 2 ee Cem. - Sep 4,000 2 The method illustrated in the last line of Table 2 obviously shows with a minimum of calculation on the part of the reader that one of the solutions is two thousand times as acid as the other; and it gives directly the information that the hydrogen-ion concentration is in the one case four thousand times, in the other case twice, that of pure water. As the Py method is rather widely used in the statement of hydro- gen-ion concentration, however, it seems desirable that another table be given showing the relations between Py values and specific acidi- ties (and alkalinities) over the range covered by dilute aqueous solutions. 250 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. TABLE 3.—Specific acidity and alkalinity equivalents of PH values. Specific Specific Pu Xu acidity Pu Xa alkalinity. 6.0 1-0 10 (10.00) 7.0 0.0 1 (1.00) 6.1 0.9 8 (7.94 oe! —0.1 1.3 (1.26) 6.2 0.8 6 (6.31 1.2 —0.2 1.5 (1. 58) 6.3 0.7 5 (5. OL 7.3 —0.3 Z *(2700) 6.4 0.6 4 (3.98) 7.4 —0.4 2.5 (2..51 6.5 0.5 3 (3.16) 7.5 —0.5 3 re 16 6.6 0.4 2.5 (2.51) 7.6 —0.6° 4 (3.98) 6.7 0.3 2 (2.00 tan —0.7 o B(5201) 6.8 0.2 1.5 (1. 58 7.8 —0.8 6 (6.31) 6.9 0.1 1.3 (1.26 7.9 —0.9 8 (7.94) 7.0 0.0 1 (1.00) 8.0 —1.0 10 (10.00) (For each lower Px unit, multiply the | (For each higher Py unit, multiply the specific acidity by 10) specific alkalinity by 10 The substances which may yield hydrogen-ion to the soil solution are listed in the following table: TABLE 4.—Soil constituents yielding hydrogen-ion. 1. Directly (when treated with water alone): A. Inorganic. (a) Strong, highly ionized acids, like hydrochloric, sulphuric, ete. (0) Weak, slightly ionized acids, especially carbonic. (c) Acid salts, like potassium acid sulphate, which may be moderately or slightly ionized (as acids). (d) Salts of weak bases with strong acids, like aluminium chloride, ammonium sulphate, ete., which are slightly hydrolyzed, and therefore yield a small amount of hydrogen-ion. B. Organic. (a) Strong, highly ionized acids, like oxalic. (b) Weak, slightly ionized acids, like acetic. (c) Acid salts, like potassium acid oxalate, which may be moderately or slightly ionized (as acids). (d) Salts of weak bases with strong acids, like aluminium citrate, am- monium oxalate, etc., which are hydrolyzed, as in A (qd). (e) Amino acids, like aspartic (aminosuccinic) acid, which are inter- nal salts in the sense that the acidity is neutralized by the amino group, and which may be moderately or slightly ionized. (f) Humic acids, which, if they exist at all, are slightly ionized. 2. Indirectly (avhen treated with solutions of salts): A. Inorganic, especially colloidal clay. B. Organic, especially colloidal humus. From the above tabulation it is evident that soil acidity is likely to be a rather complex phenomenon, and it is certainly misleading for an investigator to look to any single substance or type of sub- stances as the source of the hydrogen-ion producing it in all cases. It seems probable, however, that comparatively few of these possible sources of hydrogen-ion, and accordingly of acidity, coexist in appre- ciable amounts in any one soil. It is desirable to tabulate next the methods which have been sug- gested for measuring soil acidity, in more or less chronological sequence, bringing together related ones. SOIL ACIDITY—WHERRY. 251 TABLE 5.—Methods of measuring acidity present and producible in soils. 1. A salt solution is added to the soil; for this purpose there have been used sodium chloride, potassium chloride and nitrate, calcium chloride, nitrate and acetate, zinc sulphide plus calcium chloride, etc. The quantity of acid in the resulting solution, which represents that originally present in the soil plus a much greater amount produced indirectly by the processes outlined on a previous page, is then determined by titration or other means. 2. No salt solution but some pure water is added to the soil. A. The mixture is titrated with lime water, using either an indicator or observation of the freezing point to determine the end point. This gives the amount of lime needed to neutralize the acid originally present in the soil plus that produced indirectly by the action of lime (which is likely to differ from that produced by a neutral salt solution), as well as the amount of lime required to satisfy the adsorptive power of the soil colloids for calcium-ion under the given conditions. B. The mixture is filtered and the filtrate titrated with standard alkali. This gives the quantity of acid present in the soil. C. The hydrogen-ion concentration or specific acidity is determined: (a) By catalysis of an ester. (6) By measurement of the potential due to hydrogen-ion with the potentiometer. (c) By observation of color changes of indicators whose relations to hydrogen-ion concentration are known. The methods listed under 1 in Table 5 are not methods of de- termining the acidity originally present in a soil. The results they yield are composite, representing both acid originally present and a usually greater quantity produced by the treatment. That the re- sults obtained would differ widely with the salt used and with the conditions of the experiment would naturally be expected, and has been demonstrated by actual trial. Even when soils are neutral or alkaline at the start they may develop a considerable acidity when treated with a salt solution; and any method which indicates an alkaline soil to be acid is certainly valueless for the determination of the effect of acidity on plant growth. By way of analogy, suppose a man has one pocket full of coins, and another full of slugs. In so far as his ability to purchase com- modities is concerned the contents of the former pocket is alone of significance. Even though the slugs can, by appropriate procedure, be converted into coins, they have only potential and no direct pur- chasing power. Determination of the total number of metal objects, or of the total weight of metal, which the man carries, can, of course, be carried out with as high a degree of precision as desired; but what bearing will this data have on his actual wealth? Since the methods in this group yield composite, variable, and con- tradictory results, and furnish no information as to the soil acidity nor as to the lime requirement, it can only be concluded that they 252 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. are valueless in connection with any study of soils in relation to plant growth. Of the methods listed under 2 A, in Table 5, the lime-water (Veitch) method gives directly the amount of lime needed to bring the soil to the degree of acidity or alkalinity shown by the indicator used. If phenolphthalein is selected, the result is the amount of lime which will give the soil a specific alkalinity of 30. If, however, litmus or brom-thymol blue were to be used, the amount of lme required to render the soil neutral would be obtained. This method, then, though obviously not permitting the determination of soil acidity, is a real lime-requirement method. The method given under 2 B, in Table 5, permits the determination of the quantity of acid present in a given soil in the simplest possi- ble way. An indicator, whose color changes occur at the neutral point, should, however, be used. Neither methyl orange nor phenol- phthalein, however useful they may be for obtaining comparative results in ordinary titrations, shows when a solution has been actu- ally neutralized. When an acid solution is being titrated, the former changes its color long before the neutral point has been reached and the latter does not begin to change until well past neutrality. For reasons already explained in detail, the quantity of acid pres- ent in a soil is far less significant than the hydrogen-ion concentra- tion or specific acidity, when effect upon the growth of plants is under consideration. The methods under 2 C, Table 5, are, therefore, the only ones which should be used in studying this subject. Method a is difficult to apply and to interpret. Method @ is justly resorted to for testing soils where the necessary apparatus is available. The indicator method ¢,* while less accurate than the potentiom- eter method, is, however, so simple to apply that it can be recom- mended for use in all ordinary studies of soil acidity in relation to plant growth. A FIELD METHOD FOR MEASURING SOIL ACIDITY.? Under the most favorable conditions it is possible by the indicator method to measure acidity and alkalinity with much greater pre- cision than is necessary in the field. By treating the indicators with buffer solutions of known ionic concentration, many hues intermediate between those in the accompanying color chart * can be distinguished. “Clark and Lubs, Jour. Bacteriology, 2, 1, 1917. Gillespie, Jour, Wash. Acad. Sci., 6, 7, 1916. 5Wirst published in Jour. Wash. Acad. Sci. 10, 217-223, 1920; reprinted with minor modifications in Ecology, 1, 170-173, 1920; here copied from the latter, with footnotes added on pp. 252-254. ®° The color chart previously published (Ecology, vol. 1, facing p. 172, 1920) was copied from layers of indicator solutions, brought to the different degrees of acidity and alka- linity, 1 cm. thick. The present one, which is intended primarily for use with a porcelain plate containing depressions 2 or 8 mm. deep, in which the colors are viewed, shows the colors decidedly paler. The colors of the solutions as shown in such a plate have been kindly copied, in oil paints, by Mr. J. Marion Shull, of the Bureau of Plant Industry, and are here reproduced from his chart by lithography. ‘uuinjoo Surpuodsat100 ay} JO pveg oy} 4% puNoj oq usY} Uv AqIUTTeY[e JO AyIplow oyloeds oy, “pourezqo orv ‘souo Suiddep10A0 OM} Jo soureIyxe Zuisoddo 10 ‘s10}ZBOIPUL eSsey} JO 9UO JO JO[OO 9yvIPEUTJO4UI UB JOYYIO [YUN sNUTZUOD, “MOTE SULA] osOY} YRIM oUT[RYB Jl ‘onyq [ouAYQUIOIG eAOGe Suis] S10}ZVOrpUl DATSSeDONS YIM yeodor ‘plow J] ‘“oUr[Vyye ‘on]q JI ‘plow si 41 ‘MOEA JI ‘[BAJNOU SI MOTPOVEI OYA ‘UseIB poIO[OD SI pmbry oy} JT “onyq jourAyyu01q jo doip & 4siy ppe ‘e[qB} SITY} JO pre oy} YYIM 49eI1}xO [IOS B Jo AYIUTTeH[e Jo Ayiplow ogloods yy ouluajop OF, -GNOLLOWYIG <—& [10s ouojseuly S>—> ~<_« yvod puzjdn »»—> Mey tare ee < ]los ,.yexe,, > <— pjoul-jeo] ss—> <—« yvad-d0q »»—> See OSL “ * * * qrepeygydjosaig * por jousyg ye * en[q jowmAYyyWOIg "+ + + + + gfdind joserow0Ig * par [AQIOY anjq Joueydmosg . m4 A. be. ~ 4 , od = —. =) 7 t J « od nia’ ‘ - " ¢ Bay i : ee i Alta 1 ll per La Cee +0008| oot | +o0e| oot | +o] or | +e | 1 | +e | ot | +08 | oor | +008] ooor [+oo0e ee a eee < oulexiy | reayneyy| pey >> got | oor| s6 | o6 | ss | os | sz] o2 | g9 | o9 | ss | og | so | oF | ge sonjtA Hd ‘qyezedns | -xyerpour | -yyeqns | ‘yyewrurm | proeuurm | proeqns | prowrpeur | provzodns sUlJe} dAtydiose(] ‘SNOILLOVEY TIOS DNININUALAC WOA CASA SHUOLVOIGNI JO SUOTOO DNIMOHS LUVHO SOIL ACIDITY—WHERRY. J53 On comparing the colors thus produced with those developed by mixing clarified soil extracts with the same indicators, specific acidities differing by a factor of °\/10 or 1.59 (Py=0.2) can be recognized. In the field, where it is inconvenient to carry buffer solutions to prepare standards for comparison, and where the turbidity of soil extracts is difficult to remove, it is impracticable to work closer than values differing by a factor of 10 or 3.16 (Pxu=0.5) which is rounded off for simplicity to 3+. This degree of precision is, however, entirely adequate for the purpose in view, for it has been repeatedly found that from one to another plant of the same species, or indeed, from one to another root on the same individual, separate observations of reaction may differ by a factor of 10 or more. The following outfit is used:7 First, a rectangular box about 3.5 by 5 by 9 centimeters in dimensions. In the box, six vials for the in- dicators, 1.5 by 5.5 centimeters, capacity 8 cubic centimeters, each provided with a cork or rubber stopper, into which is inserted a glass rod flush with the top of the stopper, and extending nearly to the bottom of the vial; to prevent undue compression upon inserting the stoppers, a groove may be cut in the side of each, so as to reach nearly to the lip of the vial. Then, three or four vials, in which to extract the soils, about 2 by 5 centimeters, made of heavy glass, to prevent undue breakage; a container for water, which may conveniently be a screw-capped jar holding 200 cubic centimeters or more, or an aluminum canteen; and a pipette, most simply con vane of two pieces of glass cies a few centimeters in length, connected by a rubber tube. The six indicators which have proved most satisfactory in work with soils are: Brompheno] blue, bromcresol purple, bromthymol blue, phenol red, methyl red, and 0-cresoiphthalein or phenolphthal- ein. The first three are used, as recommended by Clark and Lubs, in about 1 per cent solution in water, titrated with dilute sodium hydroxide to their intermediate colors; and the phenol red in a 0.5 per cent solution similarly titrated. The methyl red and phenol- phthalein are used as 0.25 per cent solutions in 50 percent alcohol. It should be noted here that litmus paper, which is often recommended for testing soil reaction, is much less sensitive than the above indi- cators, and may give misleading results.* A simplification of the procedure previously recommended has been adopted ; modifications may still be desirable in special cases. But before giving the directions, a word should be added concern- 7 Sets of indicators similar to that here described are for sale by the La Motte Chemical Products Co., 13 West Saratoga Street, Baltimore, Md. 5 Gillespie and Wise, Jour, Amer. Chem, Soc., 40, 796, 1918, 254 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. ing the water used for mixing with the soil. If calcium bicarbonate is present in this water, ‘the soil acidity will be diminished, while if neutral salts, such as sodium chloride, and especially calcium sul- phate, are present in any considerable amount, the acidity will be appreciably increased. The former effect is a direct neutralization; but the latter is due to the fact that the clay and the humus in the soil adsorb the basic elements from neutral salts and set the acid free. In the laboratory distilled water can be used, and to attain the greatest precision air freed from carbon dioxide can be blown through it until it reacts quite neutral; when one is traveling, dis- tilled water can usually be purchased from a drug store and will give satisfactory results without special purification. In the wilds the best that can be done is to obtain spring or well water rising through rocks as free as possible from soluble constituents—such rocks as sandstone, shale, or schist. In calcareous regions it may be necessary to test waters from one source after another until a sample is found which reacts neutral—is colored green by a drop ‘of bromthymo! blue indicator—and to arrange the trip so that the water supply can from time to time be replenished from this source. With these points in mind, the following approximate directions have been drawn up: A sample of soil a gram or two in, weight is shaken from living roots into an empty vial, and 5 cubic centimeters of the most nearly neutral and salt-free water available is added, the vial being shaken well to insure complete mixing. After the soil and water are thoroughly mixed, the solid matter may be compacted with a glass rod or a stick, and the vial then supported at an angle of 45° and allowed to stand until the bulk of the suspended matter has settled. The more or less clear liquid is then decanted or pipetted off into another vial,® a drop or two of bromthymol blue or one of the other indicators, the color changes of which occur near the neutral portion of the table, are added, and the color assumed is noted. If either of the extreme colors is shown, the process is repeated with the indi- cator?° whose color changes come next in the corresponding direc- ® Instead of a vial a ‘“ porcelain plate with cavities, for color reactions,’ sold by dealers in chemical apparatus or in artists’ supplies, may be used. The color changes can be seen very clearly in such a plate, but great care must be taken that too much indicator solution is not added. It is well to place a tiny drop of the indicator in one of the cavities, and then to add successive portions of the soil extract until the color can be barely seen. 10 In some soils, because of the colloid-matter acting differently on different indicators, the reactions indicated may not agree; for instance, bromcresol purple may show a color corresponding to specific acidity 10, and methyl red specific acidity 100; in this case the mean of the two values, 30+, is used. It should also be noted that the color changes are much more gradual than it was practicable to show on the chart, so that intermediate hues between those shown are often obtained, leading to reaction values between those tabu- lated. SOIL ACIDITY—W HERRY. 255 tion; and this is continued until either an intermediate color of one indicator, or opposing extremes of two overlapping ones, are ob- tained, whereupon the specific acidity or alkalinity can be read off from the chart. The more turbid the liquid the more indicator must be added, and the less certain are the results obtained. The turbidity can, of course, be removed by the addition of coagulating agents or by filtration through paper; but it is essential to make certain that these do not in themselves show an acid or an alkaline reaction. The most satis- factory results of all can be obtained by running a quantity of the extract through a paper filter until two successive portions yield the same value when tested with indicators. But such procedures are more suited to laboratory than to field studies, and after a little experience one can tell the indicator color change with certainty, even in the presence of considerable brown mud. To illustrate the procedure followed in actual practice, two typi- cal cases encountered by the writer may be cited here. 1. A black soil in pockets in limestone rock, supporting spleen- wort ferns, was treated as above, and on testing the soil extract with bromthymol blue indicator, a strong blue color was obtained; refer- ence to the chart showed that the reaction must be alkaline, and the value of specific alkalinity 3 or more (PH=7.5). The process was repeated with the indicator, the color changes of which lay next to- ward the alkaline side of the table, namely, phenol red. With this indicator a clear red color was obtained, showing the reaction to be actually specific alkalinity 10 (PH=8.0). 2. Soil from a dry blueberry thicket was tested, and, since upland peat is usually distinctly acid, the first indicator tried was brom- cresol purple, the color changes of which occur just to the acid side of the neutral point; with this indicator a yellow color was obtained, indicating a specific acidity of at least 30. The soil was accordingly tried again with methyl red, which lies next toward the acid side, and this gave a violet-red color, corresponding to a specific acidity of 300 or more. It was accordingly necessary to try an indicator working at still higher acidities, namely, bromphenol blue; and this yielded a violet color, indicating 300 or less. The last two indicators agreed, then, in fixing the reaction of this soil as: specific acidity 300 (PH=4.5). In spite of certain limitations, this method is capable of giving definite information as to soil reaction in many cases. And the re- sults obtained by the writer on a number of species of native plants have been of such significance that the method is published for the benefit of students of plant distribution and others interested in soil acidity and alkalinity. 256 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. THE RELATION OF SOIL ACIDITY TO PLANT DISTRIBUTION. INTRODUCTORY NOTE.1! As a result of many hundreds of determinations of soil acidity and alkalinity made by the above-described method upon plants growing under the widest range of physical and climatic conditions, the writer has found abundant evidence that the acidity of the soil is closely connected with the distribution of native plants. It is not intended to imply that the reaction is the only factor of impor- tance in determining the place of growth, nor that the acid or alkali necessarily acts directly on the plant. Some plants may require for themselves or for symbiotic organisms a soil of a definite acidity (or alkalinity) ; but others may be favorably affected by some physi- cal or chemical property of the soil which accompanies the develop- ment of that acidity; and still others may be driven into soils of a certain degree of acidity by more vigorous species which monopolize - neighboring soils of greater or less acidities. The measurement of the actual soil acidities and alkalinities connected with certain species of plants, which is all that is attempted in the present series of studies, is but one step in the working out of the problem of why a given plant grows in a certain place. It is hoped that the results presented will indicate, however, the considerable, if not funda- mental, importance of this heretofore often neglected step. STUDIES ON FERNS. Rock ferns.’—Judging from the literature, the ferns which grow on rocks would appear to be, on the whole, markedly sensitive to the chemical features of their soils. Their distribution is, of course, controlled to some extent by physical factors, such as climate, porosity of soil, availability of moisture, etc.; yet in many instances a given species has been observed to grow in soils of widely varying physical character, but consistently associated with a particular type of rock, and accordingly more or less uniform in chemical composi- tion. Again, soils of like physical properties but dissimilar chem- ical nature often occur in such proximity that spores of the various ferns can not fail to have fallen into both kinds, yet flourishing plants have developed in but one of them. It is commonly recognized that certain species of rock ferns grow by preference upon limestone and similar rocks, and are accordingly to be classed as calcareous soil plants. Other species, however, ap- pear to avoid caleareous rocks quite definitely, and are presumably 11 Reprinted with minor changes from introduction to an article in Ecology, 1, 42, 1920. 12 Abstracted from ‘“ The soil reactions of certain rock ferns,’ Amer. Fern Journ., 10, 15-22 and 46-52, 1920. Slight changes have been made in the table as the result of fur- ther work since the original paper was prepared, SOIL ACIDITY—WHERRY. : 257 to be classed as acid-soil plants. In the course of geological field trips and vacation outings for several years past the writer has been collecting information upon these relationships. The first plan tried was to carry samples from the field to the laboratory and there de- termine the percentage of calcium oxide (lime) present, both the total amount and the soluble portion; and a brief account of some results thus obtained has been published.1* Subsequently it proved possible to work out the above-described method for meas- uring, in the field, the soil reaction (acidity or alkalinity), which is much simpler as well as more instructive than the determination of lime. The writer’s field work on rock ferns has extended from Vermont and New Hampshire on the north to West Virginia and Virginia on the south, and all of the common species, as well as a few of the rarer ones, occurring within these limits have been studied. The results obtained are presented in Table I. The correctness of pre- vious classifications has been confirmed in most cases, but consider- able new data have been obtained on many species. As pointed out in the above-cited paper on rock ferns, it is the soil rather than the rock which affects the growth of plants; acid humus sometimes coats limestone ledges to such a thickness that species not normally favor- ing calcareous soils flourish there; and on the other hand, while the soils over sandstone, schist, granite, etc., are usually more or less acid in reaction, alkaline (calcareous) soils may accumulate on these rocks through the decomposition of vegetable débris, and typical cal- careous soil species thrive there. Accordingly, actual tests have been made of the soils at the roots of the plants investigated. It is prob- able that further work will result in extending somewhat the ranges of reaction here recorded, although it seems unlikely that the classi- fication of many of the species will be changed. It is hoped, in par- ticular, that species which the writer has been unable to study fully will be worked up by others. Method of recording data—¥or recording data on individual species the following plan has been proposed:?* Arrange numbers representing specific acidities in a horizontal line, decreasing from left to right. At the left of this line place a column of numbers, increasing upward, to show how many observations have been made. Then place X’s above each acidity opposite the number representing how many times such a degree of acidity has been ob- served at the roots of flourishing plants. A curve may be regarded as drawn through the X’s thus placed, and from its shape the be- havior of a plant with respect to soil acidity may be seen at a %3 Amer. Fern Journ., 7, 110-112, 1917. 144 Proc. Acad. Nat. Sci., Philadelphia, 1920, p. 96 et seq. 42803 °—22 17 258 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920, glance. Three illustrations from the paper cited may be reproduced here. (eb?) SEOUL. LIS. At eee se eee ge. ee This represents Clethra alnifolia, the ‘‘optimum acidity” Fn a Faas bose Bers eseos for which is plainly shown to be specific acidity 300+, vy he Be Te Sass 93-8 Ce Bee ae sod ei and the “range” rather limited, at most from acidity * bee isAB G05 > ge Sy ee acinicy to SAE = 300+ to 30+. CQ ARSE SAS > al EP A Ree cle ae For a ig 2 onl (saat ae wre | idee This represents Pyrola americana, the optimum acidity for Ge. [RETIN | which is shown to be specific acidity 30+ and the range 3 5 rather wide, from specific acidity 300+ down to 3+. 2 1 ool aided saan se | | This represents Rhododendron maximum, for which the range Agy (ino bl ee eee dldees <|ecabee is from the greatest acidity met with in normal soils down 3 KAeM ucicen| pees) ecw el soe esclae exes to the neutral point; and the optimum is apparently at ; Goeree Re fis... wae By Hes. scl. ones specific acidity 30+. Saeed | BGR ae [OAPs Se i acted 2 x x 300+] 100 | 30+ 10) 3+ 1 For comparison of a large number of species, it is simpler to indi- cate the frequency of observations of each degree of acidity by the use of different type, lower case x signifying rarely observed, capital X frequently observed, and bold face X the optimum or most frequently observed value. The three illustrations just given would appear under this plan as follows: Clethrajalnitaua’s 32.5

oy | | Se ge ee ee A S- pinnatifidum.............. DOM RAMS Hees EKA | eee. apes cael Socal aera lower A s PEAVESH coo cc cactncoSecess a 10})) SR. WERE |S caclamcslememcloswealoacclesse A Ss GrRovp 3. Sori various WVGOUSIS CIRDONG «. cacenacercinboretecuc 5 Lol a ae HN | Pelee Jeers ioe (ek: fed Ik we N Srping es sess et yh eae peel ai eli 5. Be) le ams bgp | Sle i C N SIS oo Pa iac Sue Sc Sanita Pt eee 5. Gal DY |p >. OR Ds coal | SR nea | ee cael As N Mryanienisiragrans 2. 23...232. 22555. Gye aa se (3) pe hal bes Meaty Ane bees ehh N Woodsia TIVES eee oe 30) Wan ose Ke ORNS NCR pe Me et OX | CX Ss Cystopteris bulbifera.............----- SL ferret He ae 2. Gi Hed Sl o>: Gul >. i) Sa al > be 8 N DNS a EE nn aE eae Xe eth Nia be Reale ety 1 yh Cycle Polypodium vulgare. .....--.......-.- 0 ert: TONG | ee ORS eNO eRe OK [oat G N polypodioides. ........... 1 UG PR. VDT He Cl AR CPR it Ie o> aC ee sce PAS s NOTE TO TABLE 6.—A Swedish ecologist, O. Arrhenius, hasrecently published the results of observa- tions on the soil acidity of plant associations in the vicinity of Stockholm (Oecologische Studien in den Stockholmer Schaeren. Stockholm, 1920. (In German).) Four of the above-listed species occurred there, and his data, translated into terms of specific acidity, are as follows: Asplenium Ruta-muraria, spec. ac. 10 to 3+; Asplenium Trichomanes, spec. ac. 5; Woodsia Ilvensis, spec. ac. 10 to 3+; and Polypodium vulgare, spec. ac. 13. The first of these results represents a slight extension ofrange, but the others fall within the ranges here recorded. The essential agreement of measurements made quite independently and in such widely separated regions furnishes a striking confirmation of the definiteness of the soil preferences of these species. The names used are those accepted by most present-day writers. The number of tests made on each species is recorded, and, as about three tests have customarily been made at each locality, the number of localities represented is approximately one-third of the number of tests. Tests made on soil adhering to the roots of herbarium speeimens, which seemed desirable in a few instances to supplement field data, are distinguished by parentheses. The majority of the species tabulated clearly favor reactions lying toward one side of the table or the other, and it is convenient to have 260 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. some way of classifying them on this basis. Those the dominant — reactions of which lie toward the left-hand side may be termed — “acid-soil plants.” It should be noted that the degree of acidity — represented by habitats supporting these ferns is for the most part less than that of the sphagnum bogs and sandy barrens where so- called “oxylophytes” grow, so the latter term is not desirable for application here. This class is designated by an A, for acid, in the — next to the last column of the table. The complementary term “alkaline soil plants” is unsuitable for — those showing dominant reactions toward the right-hand side of the table, since the degree of alkalinity represented is at most but slight, — and moreover no species of this class has been found which will not — grow also in neutral and even slightly acid soils. The evidence indicates that the important factor in the case of plants avoiding the most acid soils is the relative abundance of calcium compounds, and accordingly “ calcareous soil plants” will be used. The terms “calci- phile” (lime lover) and “calcicole” (lime grower) are often applied _ to this class of plants. Since plants may grow in calcareous habitats for various other reasons than “love of lime” the latter term is the ~ preferable one; but neither is really necessary. This class is marked in the table by a C, for calcareous. I, for indifferent, is used in one © instance. | It is evident from the table that no sharp line can be drawn between _ the two classes, as marked overlapping occurs in the central columns, especially in those of specific acidity 30, 10, and 3. Laboratory tests — for calcium compounds have shown these to be present in practically — all the soils concerned, their amount and especially their solubility — diminishing markedly as the reactions approach mediacidity. By no — means all species showing calcium compounds in their soils are calca- — reous soil plants; for when the specific acidity exceeds about 30 the — physiological effect of the acid appears to predominate over that of the calcium; and although when the specific acidity is 10 or below, — the effect of the calcium is dominant, some acid soil plants can still — thrive even at the neutral point. In soils termed minimacid, plants } of both classes may flourish side by side; but if enough occurrences — of each species can be studied, the dominant reaction is always found to lie definitely toward one side or the other, and the plant can be — assigned to the corresponding class. In the final column of the table letters are used—N for northern — and |S for southern—to bring out the relation between the range of — each species and its soil reaction. The calcareous soil species prove — to be dominantly northern in their distribution, the acid soil ones dominantly southern, This is evidently connected with their evo- — SOIL ACIDITY—WHERRY. 261 lutionary history and with the fact that the climatic conditions of the more northern regions, as well as the glacial action which has affected them, are adapted to the accumulation of calcareous soils, whereas in more southern regions there is, on the whole, a tendency for soils to develop acidity. Soil reaction and plant relationship.—in several cases listed in _ the above table related plants show marked differences in their soil preferences. Thus Pellaca glabella is much less tolerant of acid condition than is P. atropurpurea; Asplenium ruta-muraria and A. monianwm lie at the opposite extremities of the group in this respect; Camptosorus rhizophyllus and Asplenium pinnatifidum are _ also widely separated; the three small Woodsias form a subgroup, in _ which W, alpina is intermediate both in morphologic characters and _ soil reaction; and finally the two species of Cystopteris differ dis- = tinctly, and the two Polypodiwms markedly, in their soil preferences. On the other hand, the two ferns listed, which the evidence indi- cates to be recent hybrids, namely, Aspleniwm ebenoides and A. gravesti** do not differ essentially in soil requirements from their parents. It is accordingly reasonable to conclude that the greater the divergence in soil reaction of related species the longer time has been required for their development since their original separation. Ferns of woods and swamps.°—The ferns to which this essay is devoted are, on the whole, less sensitive to soil acidity and alkalinity than those which grow on rocks, to which attention was directed above. It seems worth while, however, to place on record what data have been obtained on testing the soils surrounding their roots, by the indicator method. The following designations are used in the class column of Table 10: AA, intensely acid; appear ring to thrive only in mediacid soils. f@ wnt growing well { in soils of practically all degrees of acidity. i feiteront (relatively) ; appearing to thrive ~ both acid and alkaline soils as long as neither reaction is extreme. C, calcareous or circumneutral; growing best in neutral or nearly neutral soils, though extending throughout what is termed the cir- -cumneutral range (specific acidity 10 to specific alkalinity 10). No Mt ates PrP SS nee instance has been observed of a species which will not grow in neutral or slightly acid soils if it thrives and is ordinarily found in actually alkaline ones. 16 Added to the list since the paper was originally published ; compare Am. Fern Journ., 10, 119-121, 1920. 78 Abstracted from paper in Amer. Fern Journ., 11, 5-16, 1921. 262 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. TABLE 7.—WSoil reactions of ferns of woods and swamps. Reactions. 9 % # 3 a ae oe 0.0 : 4 Name. tests. Ke} | S 3 = g 3 E 3 3 - Circumneutral 2 EZ q a a ; na 3) is) 300 + | 100)30+)} 10 | 3+ | 1 |3+/ 10 |30+ Seba MUSUMA soe cow ct tea aim awraisjei eects 14) 9] A. SHRP my nl (a |S |e (ee me AA Ss Lygodium palmatum.......- ingen 1K) 8 82S ol ee 85 aay Gees base ood ans eae) Se AA 8 Osmunda regalis var. spectabilis.....- SOR Moe balck ple Sie ie Bea ite accll ee Seer ene A cinnamomes. «..+.<-\-2-s:- 30) REG) PR Ke acai ise ce eae A Clbytoniana ... Sheen s- ae DOr Vise Ki sal eeu yee all ee | ee, | ee eee I Pteretis nodulosa./.......22.-+-.+--2- 20s) 262. fs aerate wo x|X|xX |x x| C | N OnGclea SenSibilis. 22 5. sta anes oe cc Te >. gan Ve. E>. alg SE Gi WD S|: HS a EP fe Dennstedtia punctilobula.........--.- Be be Oza pened tee SURE: “altos Sel ibe: % ges I Woodwardia areolata................ DA 0)g eam. Sele: Seg (apa eSB,” ae ee | ie taal (Ee AA Ss Virginieas 21) Ste tee 74d ie. Ce | UR. Gal Fee We < aa ease ress bree A s Pteridium latiusculum................ SO Xo pil Salpome t keaill aKa (eines) Ree seal one A Adiantum pedatum................-.- BONS eee) evel | OM bea | AK ox Cc Polystichum acrostichoides........... 211) inno [> i (>, 1. SN VRE Ea ae Us Ia a 0 Bran Sep oe ges eet 10 Wye sel bee 5 MOK | RG Ey) SOc ee N Athyrium angustifolium.............. LO en a ete oi > OA: Gal ON - S H fea Uee Cc ecrostichoides 4:22). y232.c0. LOGE eels ot PG. Slee. Ge pee: aa he. ee. I MSDIGHIONGOS rsa sie cicocinin gels E10) > San WR JAE Sa 7 - Si oa WS a T a IS I Ss aNneustums <5. sscbs- seees 10| x Keo] er ey Ae | Tse eels I N Dr yopteris= Aspidium = Thelypteris (includes Phegopteris). Dryopteris Thelypteris ---.-........-- | Kit WRG Ca HE ee . Sil Wh et > € a Pah |S aa Sc AP p16 Minnesna. 25 dacs. 20.552 DWilee tee OR) eal Ky OR | AK el cise [een ae I N PHOPOPLErIS Oe: oo - aa ne 20} x bi [Me SBI 9 Sw EBD ST Ws. I N hexagonoptera..-........- BO es ii Re | Mev py Ke | EY ox I MATIN ANS Se eco eeerinesecee BO Secisare B-SIDE So (ORD SH - Gig rp. Sal Mi calh a>. aes | a war.’celSa - <.-h =. - 10; xX models tatters Stee | hoon eetiohoeem AA 8 Wilixsmas sods sieeek he @) eee ealtreriec ai ee Bate: SAPP or tae Cc N CLISERBARS oo naan cane cc Bam) |= | RD: Gat (A. S R>eag mm) fB>a S.| ETS I var. Clintoniana (yee oretle: Bene ie. Samm. 491 th. Sr) BES ces bee I SPLUUWOSA nt occa ce shen D-GEA ee -61 . ON BE m e NL ie|| aa Se i var. intermedia. . 7.0 le Sy 1A. Gl >. Sl I GI Tak) Gath Ce OD. ag bc I var. americana... 3 pobeseate| NSS waa |, XGll a ceree| este |e ee ae ee A N XM oobi ore: Ser ho Pe by cy G20) | Ry 5) er) RE ae FB ax I AMATS. KO CMS hes se LOM TT ies bel Gh fo. Sed] a: G INS eh, oc C | Note to Table 7.—None of these species appears to have been studied by Arrhenius, in Sweden, but it is him tohavoasimilar rargoin apeditpeaiaiy ham atest /t,cs; chet oc ate cain Soil reaction and geographic range-——From the foregoing tabula- tion it will be seen that the ferns of woods and swamps are, on the whole, less particular than the rock ferns as to their soil reactions; in but a single case, Dryopteris Goldiana and its variety celsa, are closely related plants sharply contrasted in optimum reaction. It is, however, noteworthy that the peculiar relation found to exist among rock ferns—the favoring of acid soils by southern species and of circumneutral soils by northern ones—is likewise well marked in the present series of plants. As the same sort of relation appears to hold also with other plants than the ferns, in particular with the native orchids, it is sufficiently definite to justify inquiry into its probable origin, SorL ACTbDITY—WHERRY. 968 Circumneutral reactions are shown by soils which either contain considerable amounts of undecomposed carbonate minerals, are bathed by alkaline spring waters, or are so situated as to favor the accumulation of leaf mold. An acid reaction, on the other hand, tends to develop in soils which either lack carbonate minerals, are ex- posed to the action of rain water so that basic constituents become leached out, or are so located that peat can accumulate. In northern latitudes, or at high elevations, rocks disintegrate more rapidly than they decompose, and so, if the rocks at any locality thus situated contain suitable minerals in the first place, circumneu- tral soils may develop. Glacial deposits are especially likely to con- tain undecomposed carbonate minerals, which the ice has ground from rock ledges; and actual tests of the soils derived from such deposits in Pennsylvania, New Jersey, and the New England States, have shown that even after exposure to the weather for many thou- sands of years, since the last ice sheet retreated, sufficient quantities of undecomposed minerals are still present in many places to keep the reaction circumneutral. The territory left bare by the retreat of the great ice sheet must at first have presented an almost unbroken expanse of circumneutral soils, and the vegetation which first occupied it accordingly com- prised only plants which thrive best in such soils. Although acid soils have developed subsequently in many places, and permitted in- vasion by plants adapted to growth under acid conditions, a con- siderable number of the original occupants still persist, and are to-day classed as “ northern ” species. In more southern regions, on the other hand, decomposition usually outstrips disintegration, so that soils containing undecomposed car- bonate minerals are relatively rare. Except where limestone out- crops or where leaf mold accumulates, therefore, the dominant soil reactions are inclined to be acid, and the plants, established there since long before the glacial period, have become adapted to growth in such soils. The favoring of circumneutral soils by northern species, and of acid soils by southern ones, is thus connected with the geo- logical history of the respective regions. STUDIES ON ORCHIDS. The results which have been obtained in the study of the native orchids are here summed up in a table similar to those used for ferns, the data from three previous publications being combined.17 The species are arranged for convenience in several more or less natural groups, and are listed in each group in the order of increasing acidity of their soils. “ The reactions of the soils supporting the growth of certain native orchids, Journ. Wash. Acad. Sci., 8, 591, 1918; Table IV in Soil tests of Ericaceae, etc., Rhodora, 22, 47, 1920; ‘able 3 in Observations on the soil acidity of Ericaceae, etc., Proc. Acad. Nat. Sci., Philadelphia, 1920, 110. A few subsequent additions have also been made, 264 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. TABLE 8.—Soil reactions of orchids. Minimacid Minimalka- line. Num- Name (Gray nomenclature). ber of SS a tests, | “3 a ; 3 3 ; % : = 1 Ghoakmentald ae Bee 3 me ire eutral. Fat g 300-+|100 |30+| 10 | 3+) 1 | 3+/ 10 CYPRIPEDIUM GROUP. (Lady’s slipper orchids. ) Cypripedium candidum,.....-.-..-.--..---.-- Sileessce| se tee clonee ase 2. |e. fee Saal eG N hirsutum os JSPs. 3.6. 522 TG) Ae ES ESS ee pal eh ft. CRS C N PUDESCONS: ac ideee Reco se so oUF piece St Ra | RC RK Toe | I paryifiorim 33)... 4-202 72.22 A 8 Oe RE eR, SE ae | ha aa ATletinuMts o6)..sc6te2ocee megan's LO lao eerel os os Beane: GU ae teh] heed] oar a ae A N Reaulepytseett. etter. JIS. 3 AsO he. Got ihe CD, alt. ck ar ae pe Be) S| VAL. HABENARIA GROUP. (Spurred orchids. ) Habenariadilatatal st223 662. 12s Le 202| MAE bese Le K SPORE A Role Cc N WY PCNDOLEA Facies = as 2S = melee ae Qi fe is cist cies sere 2. he: Ga) >: SN fm. Gal la C N modixévar.)-2-0-6i51. +b. Jas Oss SSA ie. Bese tose Ke, wee | See SES Se N ObUWUSAtA sees ce obscene be eee 1G) eS 2. ED. NG |B. ip >. is Ea a oN N Orchisspectabilisicecis-e ae aac scincein eiecmen 25 me oe os sith DOL TR SRS ORE HC AE Habonarishim briaiGccs. sie. 20 = sos ose ce eee 20 |e oee a DG PS, hl ED: Gy eta eee eee A N peramocnass . 3 Sapte efit. Er bit bE pe 8 2 > Ol >. Co) ee | ¢ Som eas Ss (0fSN (606 CES) SE oR oa OAs WN Ga He Go yp. > Sid PDL itd: i A Laceray tly. .319. chee OSES Ss . ee 5) SCN EXE PR EE Ee Pe See AM VACTORG Aes Soeewie co aoe Bens ote els LO eae 2.21) Ne, 2 IVD. Gt ¢ ool SA N Hookeriser.90.0. 32. DALELE oe LO}. 222045 | REC SSC é A N OT DICHATAEe Secscisan=scece es eae ue os DD cee oe >| Wied. a eet fa, A N macrophylla. ...cs4i se. FLT .£8s Br | EE 2. IFS.) > | SAEs \e:' N MUL VOR eine aaa =i age ciom aiactere Lig We. IM > Gia. | ape es SS Stee A s clayellata..bi oe. oo SLE. Yet es 25 LE RCM REL ope Poe. SALA NAVAL cmemtce mic ac cepa sacce paeine 10) je Se TBD | NGS | (VA Hs A a | AA Cillariss32 3.Abes: ELUSS2--F REL ELE 2H VER XS [PSR eee Se AA blephariglottisizs; cocteccs.-esace == PASS Ri. WR lt ae VRS a ee ae to a NN oristatase race. pbs... oss 109) cE | AS ESSA ORRE EE = 21] RAVAS Ss Canbyll@Se)- oo cas ace sascc ceases Hay Va. See Sell be EER eller eketel re estat eee pA 8 icOlON: CK) cheer sees waednsiscsies im) |, . Siml e. s h es S Ss | IAS CAA s INCOR S detache ogies eps ostne gece Lyell Wo <5 ee lee 4 -| AA iS} POGONIA GROUP. (Bearded orchids. ) Pogoniatrianthophora:-...2-2 22s. =2-t+- ol. Gls gil I. Cc verticillata... een S.csegsateseeed..- 2051 GEC OY ES, | EXD EE | EMRE. AICI EEA. Calopogon pulchellus. <2; - sess sac nse= SS Le i bce isla | | Es PI Ls fe | Pes fe! Pogonia ophioglossoides. ....-..-.-..--------- D5 yARG a] REY eT ER ERE ISSCC. EAI AAD CIVATICHUM. cos csocch acne Umer eee (2), ie, [al papal PRES ae RSS ote AF ee Re We Ss Arethysa bulbosa-.cicjaji cds. sceciefasveiss os 10a ee. Sa Bel ered eae Ser Bene 27g SERAPIAS GROUP. (Hellebore orchids. ) Serapias Helleborine. 2... c. raed ig se ede SS ace PAL N EPIPACTIS GROUP. (Rattlesnake orchids. ) Eplpactis pubescens. «oo. o 2c -cccaieeecciceviscce ASS Was Gia \R Sie HD, Se] SD; PS 8 | 3 Bs ake a ophioides: (vars) es 42)s saci feet eee 10| x P 14>. Gala? caltsaeiieges Haas eS te A N TOSSCIRLAS So ssc cc cae aceccosacscesiess il ae 5 Gul >. SB Wo ced CSS i) eh el See] Pea N SPIRANTHES GROUP. (Twisted-spike orchids.) Spiranthes Romanzoffiana................---- (Sse eee se sb ae Ae ees Di. IR Be C N 1 Les Co FS «ee mee me anc Nee empire | Bac 5 a Pb. sinlne- Salle. , Sant Ine Sc erred ess i DIACCOR 3 6 ow > wapee mw edewtens be: 10 Ke fer fess apres alebe a atletas A Ss VOLUSUS | 5 ccisis ei cicane sates = saeis 2a (ae: ae I< e) al (Seat en PR ee ee A PrACHish Oe IIT. sees Ash hag lea [IPS >. Oh) al eS Bey HS ae BARS A beck... .acev'S....2ks ose pL Bes Gun. @ Limp. Ch me eo BP Be Basocso AA Ss ——eee see — oP er SOIL ACIDITY—WHERRY. 265 TABLE 8.—Soil reactions of orchids—Continued. co 3 8 = a aa Num- § ES Name (Gray nomenclature). ber of cs) Ly ws A a tests | 3 = =| s vo 3 | 8 g | # s 3 Circumneutral. E a 300+/|100 |30+) 10 | 3+/ 1 | 34+] 10 LISTERA GROUP. (Twayblade orchids. ) asters Gonvallarioides..<.o.2.-..20scccec0ce ss 11th ele (Rear PSS) (ee) a>. lee oa oes Pee Cc N PUDDING we ses genie SaBRS Pete So =e CON) Sac xe RE ee Ce cele aces A N SUSUPAUS «a8 awa w enn wa cawces'= sheet = CE SRE Ses So ces sees eee AA Ss TEN SE SE eee epee ees So GS) feo. a ee (en ee ene Be Bee eee AA PS) LIPARIS GROUP. (Blade-lip orchids.) Microstylis monophyllos..................---- Dilsne sol =eealnome acne eee eek Cc N PL PAM PTLHONS oon. 25's ao boces:n See seed 7 Cee 5c (i> a (cee lige ot eae (a I ‘iste See eek Beh SaaS 10 x Da [eal |). ae FS biel =| RS I N MEPTOSP VIS TINO G <2. cc apemenmeiccecccstiacsee 20.) IPOS ees eel sed a] rrcdeo ce rore A APLECTRUM GROUP. (Chain-bulb orchids.) | WAUPSO DHIDOSA.. 5. 2.52 .-8--..508. 02 dee ess] Srilemenet ssa Pa ef DRS aes eS AL Cc N Aplectrum hyemale.................-.-+----- Darl ssceme p. oah eb is Ce, IDG aa pre) eee? I N ADUIBTIMGISCOLON. . (ne. cal eg 2 dees Cc N LS Gy ee eee ee Speen Le eee Sel (Po. cen Ib. Cal [Bae cle (En 0 8 cc eA T Ss odantorigva = 5.22 -s-55- e352 rae eee KX) |cRel eXe es eae. TT NS) THACUIAD A. soos cet a ste wicca. Fh eee > aa] bp. yh i> any eee eee Ue rae A As with the ferns, the favoring of the more alkaline soils by the more northern species and of the more acid soils by southern ones is more or less distinctly brought out by this tabulation. There are, it is true, a number of species of northern range with prefer- ence for acid soils, but on the other hand all of those favoring cir- cumneutral soils are northern; and without exception the southern species grow best in acid or extremely acid soils. The explanation is no doubt the same as in the case of the ferns, namely, that many species now called northern are those which occupied the circum- neutral soils left by the retreat of the great glacier in the northern part of the continent. Other northern species may represent later arrivals, acid soils having developed meanwhile; but southern re- gions have never offered sufficient areas of circumneutral soil for species to become adapted to such soils there. 266 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. STUDIES ON ERICACEAE.?® Practically all of the members of the Ericaceae are acid-soil spe- cies, So no comparison between their “class” and their geograhpic range can be made. Nevertheless it is of interest to tabulate the re- actions which they have been observed to favor and to bring out the differences in the range of soil acidity shown by the various species. TABLE 9.—Soil reactions of Hricaceae. ot oe aft, Num- Specific acidities. Name (Gray nomenclature). ber of tests. 3004} 100 | 30+] 10 | 34 | 1 CLETHRA GROUP. Clothravalnifoliad-— 24. go ae ee ekoles fee ae Sea! 25| X x x (X) le osbeel een PYROLA GROUP. Pyrola SSBriIONG S220 2 ose clsisase Ba taceenated-+ tect tee aaaiee OW poets Sacer aeRerel ei sricrsaliue saan x Gllipticands sheet coke see hn aes eA eS 20 Reaaee ae. > SOE. < sci see Chiorantha pauciiglia cs’: 5) yo 52 82 cea caste caesar 15: | 26 1. ae xX x Xi lee Sea Chimeaphila maculatal.. = 3.5 .fs. cde neon ho gee see seaaciccine 25 | xX x x x xen pitea ai} Vey He AI I Sees Sees ems: ee Seer 25) |) xX x x x x ae Moneses wniflonasss2oF Nb ce sence ae emcee meee mie eteena 1O)|) ex x x x p. aay a Pyrola rotundifolia americana. .-.. 2.22 --.0-----5ae----e- 25.|. X x x x ox Tae SOGUING ae ts, Sets ae eee ete ot edn een ne 20) ane x x Oxi ules sore ORE SeeumdaObtusate sce koe I eee a LOo rex x x > Daan eer N Chlorabt hea COUV OLUta es easanacdaque com ceee ores 3 | 2X Ko |Lecwicslceches kaos eee asaritolia sincarmaten. . SS Leste amen es Hire ee = Thaker te als te Paaes SSN as ot SE aed a Pe ee Bud) Dee oil homee'e ca td Aa ee eee Monotropsis OGOrate: 3! 0 = bias tsic cite nara kae ete ia soe ae ietnw oe (2)) & >. Seam (eee ee Pare | Pay ea a Et RHODODENDRON GROUP. MHOCCOMENGTOMIHAMIMUMM: seen sne sen ee aiteae nates cat i518) |e. © x x x Xs x GAzales nGitlorase (seek Pts Bolte oe cee cee e eee 50 ex x x xX xX plesseee CATIGSCENGE eerste Ss Mamnacem ecm sans ttomcre ue Ae nae. x >. Sagi epee Ind sr es ALHOreschNS fod cae an pele - swept ateseeo te beneee 10} aus 28 >. oe | er ere eee or et cee (ORL oC KDA re 16) 2 ina ae pd pee Uaelha aderlbael Sv aas 1 aay 10; xX x bp: Say ee yes |i tate ie Kealinia da tifonieicncn = ses ce gia . Sim ican | |e a, ee ae (2) Doiseleuria procumpensce ose) is snes athe che - see - aes ets os 5] xX MS ploncect|- Perce Puseligee tae PHyMOUOCeCOCl eae tsetse tence car ece oem come ene ee er 5 os Ky see soe] oes tes | fee tee eee Deiopby ham pusiiolinrn 2 occ o! et ote uma eeoe me ceatee 10}; X pS F Glee eee me ae Laon cvgh ANDROMEDA GROUP. Leucothoe racemosa 25) xX x x x Ki, Sepals Lyonia ligustrina 25 | X x x 2 SmI Solloeaseio 1 DjavrerTe cy eva Te esta mane ey JUNKO dey SMe mene Ree eee ae Se 50! X x x x ase'efe 18 The combined data from: Soil tests of Hricaceae and other reaction-sensitive families in northern Vermont and New Hampshire, Rhodora, 22, 33-49, 1920; and Observations on the soil acidity of Ericaceae and associated plants in the Middle Atlantic States, Proc. Acad, Nat. Sci., Philadelphia, 1920, 84-111. In the present compilation a few additions have been made, as the result of further tests, chiefly in the State of Virginia. The “ names in parentheses are subgeneric in Gray’s Manual. The acidities in parentheses represent tests in nurseries or on herbarium specimens, —_ SOIL ACIDITY—WHERRY. 267 TABLE 9.—Soil reactions of Ericaceae—Continued. Specifie acidities. Num- Name (Gray nomenclature). ber of tests. 1300+] 100 | 30+ | 10 | 34+ | 4 ANDROMEDA GROUP—Continued. | Ceysentrummlarpureums))/! 80/0 vas see ete tes So ee A AHG bee. Geultnenia procumbens - i oo eo eT ee sa 50}. Xx @hambedapnne calyculatal.. 22 Aaa eer a 5| xX TRON AIATIONG = 5 day = tein wae ois «meine oe aE yrmsned ae = ato 20; xX DOMINIC MOLI A Se oo soe etn seme cee ee nan cece se 5| xX RIBU COND VIE oo ee se ase ec Nee ens 5] Xx POSSE U9 S01 Gi ee i aie Rigi — Ben Bere We A, 5| xX PEMCUnOS ARIUATISE — onions hop sane cane eons «= pomn d= ncn 5| xX Lyonia ligustrina foliosiflora.............-........-----+--- 5| xX UST gee a eee bined 95 Bao: es Sea ee eae. 2 ARCTOSTAPHYLOS GROUP. Arctostaphylos Uva-Urst..-- 20 -. 02 - == ao- soe late eneee TKD ES 5. x x x x x HPAEs Soc ie ciice nats coon InSb aoc hese 5; xX Kye oscmetane oe [ee oer: (?) VACCINIUM GROUP. Gaylussacia baccata...-..--..:...-.-.---.---.------------- 25 {| x x x x x x VRGEHInAVACIIADS 2.522.) o2 ee oe Cea ee owe 50) xX x x x x x SiaIMMNOCUMN EE! : 5 Fle ote sede ce as Socwe masala y 25) x x x x Naas oe re COLYMPOSUIMN Ss a2 . sop ete ol sates tees ee 50| X xXx x xX > oh Ee SUPUCGUCEIST ora pin wt ae ce sales Sate ete Colne ea orclarn 20 | x x x x 5 Sy Paces pennsylvanicum. i.6 bse 0s. ATO 15) X x x 5. Cio: | CANACENSOD so oia ba ee oe sans so arss iss seeeeseoctinels 152} ak x xX eS See eet ACS piiOSUM S65 eG ste resi Ae. bee Sete 5) XxX x 2S | reel (?) BY GOCOCAT DUES . Sy DE ee ee ees Se es WirpatiN GENeNGM ao 20. os. 2s vasaoenscce tact ee Riad be i Pee ape) (ae ae al Pee oe ee ee CayIMSSaCae GUIMOSB an 22. nae ease ee eee es eena ae LH eee. Onn Eee See Se pe ee a ae DIAPENSIA GROUP. Galamapliyiinera. snp a. e-nsasecatescsas caer s-seasateeeene 10; xX x 8 I an, + | i eee Pyxidanthera barbulata........---...---.---...----------- 10; xX x Keyactesse bees al saidecrs DyAPEnNAIBYPORICR.. jo8ee ries soca a eee eeu ecee ody 5| xX Ret segs S| oes aes eee She Bees EMPETRUM GROUP. COMI MCOUTACH. 222. . eee seks <0 Vea tads ood acee sect suees 10; xX x LOTTE Le] DOS01G 01 fed qo 001 Depo eM ne es Soe pat A Se en By, ok = “nigrum andinum”=atropurpureum ......... Ma few. © x Note to Table 9.—Several of these Ericaceae were studied by Arrhenius in Sweden, giving the following data: Pyrola secunda, sp. ac. 100 to 10; Arctostaphylos species, sp. ac. 300+- to 1; Vaccinium Vitis-Idaea (el varietally distinct from American plant), sp. ac. 1000 to3+; and Empetrum nigrum, sp. ac. 100 05. CONCLUSION. In addition to the studies of plant groups above described, special problems of plant distribution have been investigated from the point of view of soil acidity. It has been found * that the vegetation areas of southern New Jersey differ distinctly in the acidity (as well as the salt content) of their soils, and this may well account for the * Correlation between vegetation and soil acidity in southern New Jersey, Proc. Acad. Nat. Sci. Philadelphia, 1920, 113-119. 268 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. peculiarities of the flora of the Pine-Barren area. The presence of plants, often found in peat bogs, around the borders of salt marshes can likewise be explained on the basis of soil acidity.” The application of these methods to the study of the soil for the cultivation of native plants has only just begun, but it has proved easy to grow a number of species ordinarily regarded as impossible to cultivate by seeing to it that the soil possessed a reaction approach- ing that which had been found to be optimum for the plants in nature (as shown in the tables above). By way of illustration of _ what can be done along this line, two photographs of Shortia galaci- folia in the writer’s garden are here reproduced on plate 2. The upper picture shows how this plant behaved the first year after re- ceipt from a nursery, in which it had been grown in soil of a low degree of acidity (specific acidity 3). The plant was placed in soil of specific acidity 100, and the lower picture shows what happened the next year. Its optimum acidity is evidently nearer the second than the first specific acidity. 20 Plant distribution around salt marshes in relation to soil acidity, Ecology, 1, 42, 1920. Smithsonian Report, 1920—Wherry. PLATE 2 late é - ae ” PE pee ce tg Oe I. SHORTIA GALACIFOLIA GROWING IN NEUTRAL SOIL IN GARDEN OF THE WRITER, WASHINGTON, D. C. 2. THE SAME PLANT AS FIGURE I, AFTER GROWING FOR ONE YEAR IN SUBACID SOIL. THE FIVE-FOLD INCREASE IN SIZE SHOWS CLEARLY THE PREFERENCE OF THIS PLANT FOR ACID SOILS. THE CHEMISTRY OF THE EARTH’S CRUST: By Henry S. WAsHINGTON, Pu. D., Petrologist, Geophysical Laboratory, Carnegie Institution of Washington. INTRODUCTION. The term “ Crust of the earth” is a heritage from the days when the interior of the earth was generally conceived to be a “sea of molten rock,” at an enormously high temperature, covered by a rela- tively thin, solid crust of cooled matter. Various cogent reasons, into the consideration of which we can not enter here, have led to the abandonment of this concept, and we now have reason to hold the following tenets as to the conditions that obtain in the earth’s interior : 1. The interior is essentially—or, at least, behaves essentially like— a rigid solid, though possibly a certain amount of viscosity may be granted. 2. It is hot, but of an unknown temperature, and probably in- creases in temperature toward the center, with a gradient that is unknown beyond very moderate depths, and that is probably very different in different places. 3. It is of a density greater than that of the “ crust,” inasmuch as the mean density of the earth as a whole is about 5.55, while that of the crust is about 2.77, as will be shown later. 4, The earth, as a whole, acts in many respects as a magnet, and as the rocks of the crust in general are not notably magnetic, this may be attributed to the characters or composition of the interior materials. 5. From the study of the propagation of earthquakes we are led to believe that there is a change in the physical properties at about 0.5 of the radius in depth, the matter below this not transmitting transverse vibrations. Studies on the compressibility of rocks by Adams and Williamson, in the Geophysical Laboratory, indicate that the high density of the interior can not be explained by compres- 1 Reprinted by permission from the Journal of the Franklin Institute, December, 1920, based on a paper presented at a meeting of the section of physics and chemistry held Thursday, Mar. 4, 1920. a 269 270 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. sibility, so that we have reason to think that there is also, toward the center, a change in actual substance. 6. It has been often suggested, and is more or less commonly be- lieved, from consideration of the density and magnetic character of the earth and from the composition of many meteorites, that part, at least, of the interior is composed essentially of iron, or of nickel- iron alloy similar to those which constitute the iron meteorites. Leaving the interior of the earth for the present we may con- centrate our attention on the outer shell—the so-called “ crust ”— which is the only portion that is directly open to our study, and which has been compared, with some justice, to a covering of slag or scoria over the interior. In dealing with this we shall consider only its chemical characters, with, toward the end of the paper, some relations between these and the densities of rocks. The thickness of this crust is, of course, unknown, probably not uniform, and presumably indeterminate. Following Dr. F. W: Clarke, we may assume, for purposes of computation, an approxi- mate thickness of 10 miles (16 kilometers), this being about the (minimum) aggregate thickness of all known rocks and deposits of the various geological ages that have become exposed to our ob- servation and study through movements in the crust. Incidentally, it about equals the sum of the highest land elevation and the greatest oceanic depth, though no causal nexus is apparent. This solid crust is made up almost wholly of igneous rock—that is, rock that has solidified from a hot, liquid (“ molten”) condition, either as “ plutonic” rocks, at different depths beneath the surface, or in the form of lava flows at the surface. Assuming a thickness of 10 miles, Doctor Clarke? has estimated the rock composition of the crust to be about as follows: Per cent. fomeoussrocksvaua ot Alor # an otras ont ta citsash, 95. 0 Shales.2 2.252 ou wetel ewan nd ee SN Ba 4.0 SS SINE GUS BY SoS a esse EI See ee a ed 0. 75 MRTRV ST OTC eh ea cides goes Sr eee aan SR TIRE Pe Ui fc eR 0. 25 100. 60 Such masses as coal beds or salt and ore deposits are of negligible magnitude in studying the chemistry of the crust as a whole, as it is purposed to do here, though their presence is of some significance. The amount of the coating of soil is absolutely negligible from this point of view. When we take into consideration the oceans and the atmosphere, Clarke estimates the lithosphere at 93 per cent, the hydrosphere at 2 Clarke, F. W., The data of geochemistry, U. S. Geol. Survey, Bull. No. 695, p. 38, 1920. The proportion of igneous rock would be still greater with greater assumed thickness of erust. ee eee eee EARTH’S CRUST—WASHINGTON. A | 7 per cent, and the atmosphere at 0.03 per cent, of the complex crust. In the following pages, however, the hydrosphere and the atmos- phere and the. sedimentary rocks will not be taken into account, and we shall consider the “crust” as made up wholly of igneous rocks. This is the more justifiable for our present purposes, because the material of the sedimentary rocks has been derived entirely, either - directly or indirectly, from preexisting igneous rocks, while the metamorphic rocks (gneisses, schists, etc.) have been formed from either igneous or sedimentary rocks. When we consider, then, only the igneous rocks of the earth as a whole, we know that they are not all alike, but show wide differences in their characters, chemical and physical. There are here two main questions regarding them to be considered. The first is: What is the average chemical composition of the igneous rocks of the crust? The answer to this is of considerable importance for the investigation of the constitution of the earth, and is also of interest in the study of the rocks themselves—the science of petrology. The second question is: Do the igneous rocks, taken as a whole, show sensible uniformity as to general characters, or do they differ noticeably in different portions of the earth’s surface? That is, is the earth’s crust sensibly alike or unlike? Attempts to answer these questions, with some consequences that seem to follow from their consideration, will form the chief topics of this paper. GENERAL CHARACTERS OF IGNEOUS ROCKS, For present purposes we can not go deeply into the characters of igneous rocks, nor discuss them all—a subject that has produced a very voluminous literature. It is needful here to present only some of the salient and pertinent facts. Igneous rocks, as has been said, are those that have solidified from a state of fusion, or rather liquidity, as the term “fusion” implies a previous solid condition. The liquid matter, that even- tually solidifies as a rock, is called technically the “magma,” a term that is in frequent use in petrology. The magma comes up from below; from what depth we do not know, though there is some reason for thinking that the places of origin are not very deep. Nor do we know whether it arises from the melting of portions of the earth that are actually solid but potentially liquid on relief of pressure, or whether it is, in general, derived from “reservoirs” of liquid magma. 272 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. The igneous magma may be compared, as it usually is, to a com- plex solution of salts in water. This idea, which was first suggested | by Bunsen in 1861, is of great importance, and has been very fruitful in our study of the origin, formation, and characters of igneous rocks. Among other things, it may be mentioned here that the magma contains various gases in solution, much as air is present in solution in spring water, or, rather more appropriately, as carbon dioxide is present in the waters of many mineral springs, so that it escapes on relief of pressure. Of these gases by far the most important, and generally the most abundant, is water vapor. This forms the major part of the clouds that are given off during volcanic eruptions, and, with other gases, produces the spongelike structure of pumice and the cavities of vesicular lavas through expansion, caused by relief of pressure on reaching the surface. In some glassy lavas water is present to the extent of several per cent, the magma having solidified so rapidly as not to permit of its escape, and inclusions of visible water and liquid carbon dioxide are present in the crystals of many granites and other rocks. The presence of water in volcanic magmas has been doubted by Brun and others following him, but its existence in lavas, especially those of Kilauea, has been shown conclusively by the researches of Day and Shepherd,’ is shown by practically every rock analysis, and in other ways, so that the existence of water in magmas may be regarded as one of the established truths of the chemistry of igneous rocks. Besides water, other gases are often present in volcanic ex- halations, such as carbon dioxide, carbon monoxide, hydrogen chlo- ride, sulphur trioxide and dioxide, hydrogen sulphide, hydrogen fluoride, ammonia, methane and possibly other hydrocarbons, sul- phur vapor, hydrogen, nitrogen, oxygen, argon, helium, and other rare gases. The study of these and the bearing of their interreactions on the maintenance, and possibly the partial production, of volcanic heat, is an interesting subject. The presence of these gases in the magma lowers its solidifica- tion point, so that a lava, on coming to the surface, may be, and usually is, liquid at a temperature considerably below the fusing point of the solid rock formed from it, during which solidification much, if not most, of the dissolved gas is lost. Either because of this, or because of the lessened viscosity, or in some other way that is not yet well understood, the gases contained in the magma seem to promote the crystallization of minerals, so that they are often 8 Day and Shepherd, Bull. Geol. Soc. Amer., xxiv, 573, 1913. = eeelaieonss I Ie 2 a EO EARTH’S CRUST—-WASHINGTON. 273 referred to as “mineralizers.” These gases also play an important part in the formation of many ore bodies. The magma on solidification generally forms a mixture of minerals, substances of definite chemical composition, and physical characters, _ just as a solution of salts in water (such as sea water), forms a mix- ture of crystals of salts and ice on freezing. The exception to this is when the cooling of the magma takes place too rapidly for com- plete or (as with the obsidians) any crystallization, in which case the rock is composed partly or wholly of glass. Such glassy rocks are found only as surface flows. MINERAL CONSTITUENTS OF ROCKS. It is a very important and striking fact that, although about 1,000 different minerals are known, yet the number of the different kinds that compose by far the great majority of igneous rocks—certainly _ over 99 per cent by weight of these—is very small. Indeed, the really important and essential igneous rock-forming minerals number only about a dozen. These essential minerals are quartz, silicon dioxide; the feldspars, silicates of alumina and potash, soda, or lime, including the potassic orthoclase, the sodic albite, and the calcic anorthite, with isomorphous mixtures of these; the pyroxenes, metasilicates of calcium, magne- sium, and iron, with aluminum or sodium in some cases; the am- phiboles, in chemical composition much like the pyroxenes, but differ- - ing in crystal form and otherwise; the micas, alumino-silicates, for the most part the potassic muscovite or the potassium-iron-magne- sium biotite, both containing hydroxy]; the olivines, orthosilicates of iron and magnesium; nephelite, an orthosilicate of sodium and aluminum; leucite, a metasilicate of potassium and aluminum; mag- netite, ferroso-ferric oxide, often containing titanium; and apatite, a phosphate of calcium, containing a little fluorine or chlorine. Mag- _ netite and apatite are present in almost all rocks, but seldom in more than almost negligible amounts. Other minerals are not infrequently met with in certain types of igneous rocks, such as the silicates sodalite, hauyne, melilite, zircon, and garnet, and the oxides tridymite (a second form of silica), ilme- nite, chromite, spinel, corundum, and rutile. But, considering igne- ous rocks from the standpoint of a study of the whole crust of the earth, these are practically negligible. Tgneous rocks, then, in gen- eral, and looked at in the broadest way, are constituted almost wholly of a very few silicates of aluminum, iron, calcium, magnesium, sodium, potassium, and hydroxyl, with or without quartz (that is, excess of silica), with small amounts of a phosphate and of iron 42803°—22——_18 274 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. oxide, and with or without traces of other constituents. It is also to be noted that some of the essential minerals enumerated above (the pyroxenes, amphiboles, micas, olivines, and the magnetites), contain small amounts of manganese and titanium. From such a general survey of the rock-forming minerals, then, we obtain the broad lines of the chemical composition of the earth’s crust as a whole. Another important fact concerning the igneous rock minerals is that, with two exceptions, any one of them may occur in rocks with any one or more of the others. The only exceptions to this are that neither nephelite nor leucite is known to occur along with quartz, and a partial exception is that olivine seldom occurs with quartz, and never in any large amount. Discussion of this and other relations between the various minerals would lead to a consideration of matters outside of our present scope, and would take us too far afield. Each rock mineral may be present in very widely varying propor- tions—from practical totality to complete absence. We know igneous rocks that are composed entirely of quartz (arizonite), feldspar . (anorthosite), pyroxene (websterite), amphibole (hornblendite), or olivine (dunite), and almost entirely of nephelite (congressite), leucite (italite), or magnetite (some iron ores). Of the essential rock minerals only the micas and apatite do not form the whole, or almost the whole, of any igneous rock. From totality of any one mineral we find rocks that are composed of two minerals, more that are composed of three, and still more that are composed of more than three, and with the widest possible varia- tions in the proportions of almost all, with the exceptions noted above as to the non-coexistence of quartz with nephelite and leucite, and its rarity with olivine. CHEMICAL CONSTITUENTS OF IGNEOUS ROCKS. From what has been said it would appear that the various oxides (in terms of which the chemical composition of rocks is usually for- mulated) may be present in widely different amounts, and, within limits, this is found to be true. All of the constituent oxides have very considerable quantitative ranges, but these differ much with the different oxides. Their possible or recorded maxima are also very different, though in every case the minimum is reached with complete absence. These ranges and maxima will be stated later, after a brief discussion of the oxides that go to make up the igneous rocks. Though, as we have seen, most igneous rocks are composed of but. few essential minerals, and consequently of but few so-called “ major ” oxides, yet when we come to study them in detail we find that a very considerable number of different chemical constituents may be present EARTH’S CRUST—WASHINGTON. 275 in the different rocks. Altogether, about 23 are to be found, and are more or less commonly determined and recorded among the better- class rock analyses. Indeed, as has been said by Dr. W. F. Hille- brand, the foremost analyst of rocks, “a sufficiently careful exami- nation of these [igneous] rocks would show them to contain all, or nearly all, the known elements, not necessarily all in a given rock, but more than anyone has yet found.” Proper study, therefore, of the chemistry of igneous rocks, and their chemical analysis, if this _be complete as to the determination of all the constituents probably present, is evidently a somewhat complicated matter, and one not without difficulties of various kinds. From the many chemical analyses of rocks that have been made since this was first attempted tery early in the nineteenth century (the total number of published rock analyses is now about 12,000), we have a good idea of what chemical constituents make up rocks, their relative abundance, and their various ranges in percentage. By far the most important and generally the most abundant are what are called the “ major” constituents. These are nine in number and, stated as oxides, are: Silica (SiO,), alumina (AI,O,), ferric oxide (Fe,O,), ferrous oxide (FeO), magnesia (MgO), lime (CaO), soda (Na,O), potash (KK,O), and water (H,O).t Together these nine oxides make up about 98 per cent of igneous rocks, and all of them are present in greater or less amount. in practically every rock, so that the amount of each must be determined in every chemical anal- _ysis of a rock that makes the slightest pretense to good quality. As the most abundant and essential rock minerals are either silica or silicates, and as all igneous rocks, with the exception of some rare and small iron ore bodies of magmatic origin, are consequently sili- cate rocks, silica shows easily the highest maximum and the widest range, both in extremes and in the usual run of occurrence. A few igneous rocks are known that are composed almost entirely of quartz,° and the highest silica percentages recorded for igneous rocks are 98.77 and 97.65, in rocks from the Transvaal, while one from Cum- berland (England), the border facies of a granitic mass, shows 96.16, one from Massachusetts shows 93.38, and one from Arizona 92.59. In general, however, the percentage of silica ranges from about 75 to about 34, and it drops to zero only in some “ magmatic” iron-ore bodies. In almost all rocks it is the most abundant constituent. Alumina, which is almost invariably the next most abundant constituent, reaches a maximum of about 60 per cent in some corun- dum-bearing syenites from Canada and the Urals, and has a general *This order is not quite that of relative abundance, but that which is commonly used in the statement of rock analyses. 5 Quartz veins are not considered here, as they are usually of nonigneous origin, at least _ in the commonly accepted sense. 276 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. range from about 20 to about 10.- It is wholly absent only in the “magmatic” ores and in some rocks that are composed entirely, or almost so, of olivine. The two oxides of iron reach, of course, their maxima in such rocks as the iron ores already spoken of;® the highest figures recorded for Fe,O, being 88.41 (Sweden) and 62.39 (Ontario), while for FeO they are 34.58 (Sweden) and 32.92 (Min- nesota). Their general range is from nearly 15 for each (FeO gen- erally higher than Fe,O,) and but little more than that for both together in any one rock to less than one-half of 1 per cent. Iron is seldom entirely absent. Magnesia reaches its maximum in the almost purely olivine rocks (dunites) of North Carolina, 48.58, and of New Zealand, 47.38, but its general range is from about 25°to much less than 1 per cent. Lime is highest (22.52) in some pyroxenites of the Urals and almost as high (about 20) in the anorthosites of Canada and elsewhere, but it ranges in general from about 15 to nearly zero. Of the two alkalies, soda reaches a maximum of 19.48 in a rare rock from Canada, and of 18.67 in another from Turkestan; but its general range is from about 15 per cent down to nearly zero. It is hardly ever entirely absent. Potash shows a somewhat smaller range than soda, its maximum being 17.94 in a recently discovered lava from Italy, the next highest figure being 11.91, from Wyoming; but in general it seldom gets above 10 per cent, ranging from that down to zero. Its amount is generally less than that of soda. As regards water, the last of the major constituents, a few volcanic . elasses are known which, although perfectly fresh and undecomposed, contain up to 8 or 10 per cent, and there are some fresh crystalline rocks that contain from 3 to 5 per cent. Generally, however, if a rock contains more than about 2 per cent of H,O this can usually be attributed to alteration, though few rocks are quite free from this constituent. After the major come the “ minor” constituents, which are almost always present in very small amounts, seldom over 2 per cent for any one, or rarely up to 5 per cent for all of them, in any one rock. Of these minor constituents three are of special importance, partly be- cause of their almost constant presence and partly because they are generally present in largest amount. These three are titanium diox- ide, phosphorus pentoxide, and manganous oxide, and all three should be determined in a good rock analysis. Titanium dioxide (TiO,) reaches a maximum in some very rare rocks from Virginia (69.67 and 65.90) and Quebec (53.35), but as a general thing its percentage is seldom over 5, and is mostly from about ®It is a question whether all of these ore bodies are to be considered as really igneous rocks, though some undoubtedly are. * EARTH’S CRUST——WASHINGTON. OT 2 to nearly zero. Of the many rocks of all kinds that I have analyzed, there has not been a single one that did not contain titanium, in some cases in very small, but always in easily determinable, quantity. This is also the experience of Doctor Hillebrand,’ and probably of every other experienced analyst of rocks. The maximum for phosphorus pentoxide (P,O,) is but a little above 16 per cent in some highly unusual rocks from Sweden and Virginia, that are composed largely of apatite, with titaniferous magnetite or rutile. In few rocks, however, is it above 3 per cent, and its general range is from about 1 per cent to zero. It does not seem to be present so constantly as titanium (or manganese), as one occasionally meets with a rock that shows no trace of it, though this may be because of the more delicate tests for the other two. Manganese, as manganous oxide (MnO), is present in practically every rock that has been analyzed, but its maximum is much lower than those of titanium and phosphorus oxides. Some, if not most, of the high figures reported for it are almost certainly due to analyt- ical errors, and the highest recorded figures that are trustworthy are 1.90 and 1.46 in two rocks from Bahia, Brazil. Its general range is from 0.3 per cent to nearly zero. The other minor constituents that are readily determinable, aud many of which are indeed determined in good analyses, are quite varied. The list is as follows: Carbon dioxide (CO,), zirconia (ZrO,), chromium sesquioxide (Cr,O;), vanadium sesquioxide (V,O,), the “ rare earths” ((Ce, Y),O,), nickel oxide (NiO), strontia (SrO), baria (BaO), lithia (Li,O), sulphur as both sulphide (5S) and sulphur trioxide (SO,), chlorine (Cl), and fluorine (F). To these might be added boron, cobalt, copper, glucinum, lead, molybde- num, nitrogen, and zine, which, however, are present almost always. in such extremely small amounts, or the analytical difficulties are so great for the separation of the small quantities in which they occur, that their determination is rarely attempted. The maxima and ranges of some of these may be briefly stated. Carbon dioxide may be present, as a component of a few minerals (as in primary calcite and cancrinite), in some unaltered rocks; but its presence is generally due to alteration. In one calcite trachyte from Spain its amount is 7.69 per cent, and in cancrinite rocks it may reach about 1.70, the carbonate minerals in these being apparently primary. But it is generally considered as a measure of the alteration of the rock by weathering. Zirconia is much less abundant than the closely related titania and, though it reaches a maximum of nearly 5 per cent in some Green- _ land rocks, in general it seldom is over 1 per cent, is usually much 'Hillebrand, W. F., U. S. Geol. Survey Bull. No. 700, p. 25, 1919. 278 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. less, and is quite absent from most rocks. It forms, by the way, one of the most striking illustrations of the correlation of the occurrence of different elements in different kinds of rocks, as will be brought out later. Baria and strontia are very commonly present, though they are seldom determined in analyses made outside of the United States, Canada, and Australia. In almost every case the amount of baria is much greater than that of strontia, this being an exception to a gen- eral rule as to the occurrence of related elements, to be mentioned later. They both reach their maxima in certain exceptional, highly potassic rocks of Wyoming, of about 1 per cent for baria and 0.3 for strontia; though usually baria is present up to but a few tenths of one per cent, and strontia in hundredths. Sulphur, as sulphides, is present up to about 9 per cent ina peculiar, pyrrhotite-bearing rock from Maine, and probably in similar amounts in some sulphide ore bodies of magmatic origin in Norway, which have not been fully investigated. But, asa rule, its amount is seldom over 1 or 2 per cent, and is usually in tenths of a per cent. The highest figures for sulphur trioxide are about 2.5 per cent in rocks from Apulia and Kamerun, and somewhat lower on Tahiti, but these are exceptional, and it is usually present only in tenths or hundredths of a per cent. Much the same can be said of chlorine, the highest figures for which are those of a rock from Turkestan (about 7), one from Quebec (4.47), and one from French Guinea (2.80). It is present in many rocks, especially lavas, but only in a few tenths or hundredths of a per cent. Chromium sesquioxide is known to be present up to about 4 per cent in some ores from Greece, which are probably of magmatic origin, and is reported as between 2 and 3 per cent in some undoubt- edly igneous rocks from Baden. But these are highly exceptional, and about 0.5 may be taken as its usual maximum. It is generally entirely absent. Vanadium sesquioxide is always present in much less quantity and is usually quite absent. The oxides of the rare earth metals, chiefly ceria and yttria, reach a maximum of 1.79.in a rare type of rock from Madras, 0.6 in one from Sweden, and 0.4 in one from the islet of Rockall, but the usual maximum is only one or two tenths of 1 per cent. They are less often determined than they should be. Nickel oxide is present in some rocks up to about 0.2 per cent. The maximum amount of each of the other minor con- stituents may be placed at not over 0.5 per cent, and they are almost always found only as one or two tenths, or still more often as hundredths, of a per cent, or are absent. Indeed, for most of the minor constituents the quantities usually yielded by analysis are so small as to be significant only as to their actual presence or absence. EARTH’S CRUST—WASHINGTON. 279 A few words may be said of boron, glucinum (beryllium), and scandium, as these enter into a later phase of the subject. The an- alytical difficulties involved in their determination, for the extremely small amounts that are present, are so great that the percentage of these is seldom recorded for any rock. Yet they are all known to be rather widely distributed among the igneous rocks, boron in tourma- line, glucinum in beryl, and both in some other rarer minerals, while the widespread occurrence of scandium among igneous rocks, though in very small amounts, has been shown spectroscopically.® THE AVERAGE IGNEOUS ROCK, We come now to the consideration of the average chemical compo- sition of the earth’s crust—that is, of all igneous rocks. Apparently Dr. F. W. Clarke was the first to undertake this estimation,® basing his conclusions largely on the numerous analyses that had been made by the chemists of the United States Geological Survey. Since then he and others, Harker, Mennell, Knopf, Mead, and the writer, have published other estimates, which, it may be said here, do not differ greatly the one from the other. The latest discussion of this subject is to be found in the last edition of Clarke’s Data of Geochemistry, 1° where numerous references to the literature are given. The true estimation of the average chemical composition of the igneous rocks is by no means such a simple matter as it may appear to be at first thought, and, before we deal with it, it will be as well to state very briefly some of the disturbing factors that are involved. The matter will be treated in greater detail in a forthcoming paper by Dr. Clarke and the writer. In the first place, we know but little of the exact chemical charac- ters of the igneous rocks of many districts of the earth. This is true of the great continents of Asia and South America, as well as of Africa and Australia, in all of which we have for the most part a knowledge only of the rocks more or less near the coasts and know only in a general and very imperfect way the rocks that constitute the vast expanses of the interior portions. The same ignorance, either total or partial, holds true for many countries, such as China, Arabia, and even Brazil, India, Egypt, and Spain, in which the number of analyses is quite disproportionate to the number and masses of igneous rocks that are known to occur. A most striking example is furnished by the West Indies, where, of the igneous rocks of the otherwise well-known and readily accessible larger islands § Wberhard, C., Sitzb. kg. preuss. Akad. Wiss., 1908, p. 851. ® Clarke, F. W., Bull. Phil. Soc. Wash., xi, p. 131, 1889; also U. S. Geol. Survey, Bull. 78, p. 34, 1891. 10 Clarke, F, W., U. S. Geol. Survey, Bull. 695, pp. 24 ff., 1920. 280 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. of Cuba, Jamaica, Porto Rico, and Haiti, we do not possess a single analysis. Most of the countries of Europe are well represented, but for the most part with not very complete analyses. North America is well known, especially as to the rocks of the United States and southern Canada. The analyses of both these countries are of exceptionally high general quality. Parts of Australia, especially New South Wales, Victoria, and Queensland, with New Zealand, are well repre- sented, as is also British Guiana, and it should be said that the analyses of Australia and British Guiana rocks are almost the only ones that, as a whole, are comparable as to accuracy and complete- ness with those of the United States, which holds a preeminent posi- tion through the labors of the chemists of the United States Geologi- cal Survey. A second disturbing factor, and one that has been often advanced against the validity and representativeness of the estimates of the average composition of rocks, is that the true relative amounts of various rocks are not properly represented because of the selection of material for analysis. It has frequently happened that the petrographer has had anaiyzed rather the rare or most interesting rock types than those which, though much more abundant in the region described, are of more usual character. While this is often to be expected and, from a special point of view, is almost justifiable, yet it certainly may involve a serious disturbance in the estimation of the composition of the crust as a whole. This is so, because the most interesting types, often ipso facto, are much less abundant than the common ones, so that, as regards the relative masses of the va- rious kinds of rocks in any given region, they are disproportionately represented. It is needless here to give examples, of which there are very many; it would lead us too far into the technicalities of petrog- raphy. Although this objection is serious, and is entitled to consideration, yet it would seem, on detailed examination, not to be of the over- whelming character that is often attributed to it. For one thing, the satellitic rocks of the dikes and other small bodies (which are most prone to furnish “interesting” types), tend to be complementary to each other, through processes of differentiation, and so, as Dr. Clarke, says, “they tend to compensation, and so to approximate to the true mean.” Also, as in a number of examples from many locali- ties that could be cited, only the main body or the most prominent types have been analyzed, chiefly because of the labor or expense of making chemical analyses of rocks. Again, as I have pointed out elsewhere, the more “basic” rocks—that is, those that are lowest in silica and highest in iron oxides, magnesia, and lime—are most liable to alteration, so that many of their analyses would be ex- EARTH’S CRUST—-WASHINGTON. 281 cluded from the data selected for our purpose, for which only an- alyses of fresh and unaltered rocks are considered. These, and other considerations that might be mentioned, tend to mimimize the rather prevalent idea that the averages, such as have been calculated in former years by Dr. Clarke and me, are not strictly representative, in that the well-known apparent preponder- ance of granitic rocks is not sufficiently emphasized. Attempts have been made by some to correct such errors by weighting the average analyses of the various rock types by their areal values.* Such a procedure, however, is open to two objections: As much weight is thus allowed for lava flows, of manifestly small vertical extension, as for massive intrusive bodies presumably of much greater depth; and, as Clarke points out, “the surface exposure of a rock is no certain measure of its real volume and mass, for it may be merely the peak or crest of a large formation.” But the serious objection to any such attempts at correcting what may be, and often admittedly are, defects in our data, is that they introduce unduly the personal equation, and thus may, or are likely to, introduce other errors of unknown and indeterminate magnitude. As has been shown very briefly above, we are as yet in great ignorance as to the igneous rocks of a large portion of the earth’s surface and crust, and it would seem to be the philosophical attitude to admit this and, as Dr. Clarke says, “do the best we can with the available data.” They are admittedly not ideal, but an attempt to better them, at this stage of our knowledge, is more likely than not to make a “bad matter worse.” Let us be philosophical Italians for a mo- ment, and say with them, “ Ci vuol pazienza.” Apart from such fundamental considerations of the character of our basal data as have been all too briefly touched on above, we meet with others when we come to consider the analyses themselves. No analyses are ideally perfect, either as to accuracy or completeness, but, while it is obviously the desirable procedure to exclude from our data rock analyses that may not be up to the ideal mark that we may set, yet, by so doing, we shall inevitably reduce the number of our data so as probably to more than offset their excellence in quality. We should have and use, of course, only analyses that are perfectly accurate and complete as to the determination of all the constituents that may be present. But, “humanum est errare,” and so we must here also “do the best we can with the available data,” excluding, of course, from consideration analyses that are manifestly bad. Con- 11 Daly, R. A., Igneous Rocks and Their Origin, New York, 1914, pp. 19-46, 168-170; and Knopf, A., Jour. Geol., xxii, p. 772, 1914. 122 Clarke, F. W., Proc. Amer. Phil. Soc., li, p. 215, 1912. 282 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. sideration of this topic would lead us too far astray but it will be found discussed elsewhere.** It may also be mentioned here that, as some of the minor con- stituents are, in the course of analysis, precipitated and weighed with others, and are later determined separately and subtracted from the previous total figure, if these are not determined the figure for the main constituent will be too high. This is notably the case’ with alumina, with which are precipitated and weighed the oxides of titanium, phosphorus, rare earth metals, zirconium, chromium, and vanadium, with often some manganese. If the analysis is not com- plete as regards these constituents, therefore, the figure for alumina will be too high. As has been said above, the average composition of the igneous rocks has been estimated by several petrologists—Clarke, Harker, Loewinson-Lessing, Daly, Knopf, Mead, and myself. Clarke based his earlier estimates very largely on the analyses of rocks from the United States, as did Knopf, while Harker’s average was of rocks from Great Britain alone. In his latest estimates Clarke included rocks from all over the globe, as did I in my own computation. This also was the basis of Daly’s and Mead’s computations, though in both their estimates, which were founded largely on personal selection of what constituted “types” of various rocks, the personal equation enters somewhat unduly. As we shall see later, continental averages, or others selected from regional data, differ too much to be repre- sentative of the average composition of the whole “crust.” The basis for the present, and latest, estimate was the collection of rock analyses that has recently been published.'* This includes practically all the analyses of igneous rocks, from all over the earth, that have been published between 1883 and 1913, inclusive. These amount to 8,602 analyses, of which 5,159 of fresh rocks were con- sidered to be “superior ”—that is, satisfactory as to accuracy and completeness. Only these 5,159 analyses were used. The computa- tions of the various averages, for the whole earth, the continents, and various districts of the earth’s surface, were made by Dr. F. W. Clarke during the summer of 1919. To him I am greatly indebted for his very painstaking and laborious undertaking, and would ex- press my great appreciation of his kindness in permitting the present publication of some of his results. It must be said that there are presented here only a few of these, and that all the data in detail, with certain considerations of them, are to be published by us jointly in the near future, as a Professional Paper of the United States Geological Survey.. 18 Washington, H. S., U. S. Geol. Survey, Prof. Paper No. 99, pp. 10—26, 1917. 14 Washington, H. S., U. S. Geol. Survey, Prof. Paper No. 99, 1917. EARTH’S CRUST—WASHINGTON. 283 TaBLE I.—Average composition of the earth’s crust. 1 2 3 4 Rincon aioxigd (SiOs):. -. 34 6-0. so doce ncn aan 59. 09 58. 59 57. 78 59. 83 Aluminum sesquioxide (AlpO3)...........------------- 15. 35 15. 04 15. 67 15. 02 MErmONO RIGO ( MOsOs) ie) oo id coy. Shee ies 3 ieee hee 3. 08 3. 94 3.31 2. 62 merrotis oxide: (reo) Yr i he sss td beets 3. 80 3. 48 3. 84 3.43 Macresinm:oxide GMg@) «2.22 eG... 2 Bas sche eee 3.49 4,49 3. 81 3. 74 GCalenmeade (CaO)s 2d. ee ees 5. 08 5. 29 5.18 4, 83 Sodium oxide (NazO).............-- Eg es ee 3. 84 3. 20 3. 88 3.37 Peracsum/oxide (CK3O@)! 2.14 ssh 4 hose Ae 3.13 2.90 3.13 3.05 Var (8 0) Se ee ee Se Se ee ee 1.14 1.96 1.76 1.90 Titanium dioxide (TiO»,)-............. 1.05 . 55 1,03 .79 Phosphorus pentoxide (P.O;).-...-.- . 30 . 22 oot .29 Manganous oxide (MnO).. 125 .10 22 -10 Carbon dioxide (CO,).- .- - 102 OTs Wbicics onc oops 49 Zirconium dioxide (ZrOz) - F039) (Sea Le oS set . 023 Sc Fe Se ee 2 ee eee eros . 053 AS eee .10 Wulombpel)t de. EPL ss. ee . 056 SOUZA ee sete . 063 PAUSCH GS ne eee 5 eee ase See SUIS Se ee secs oleeeccice cease .10 Chromium sesquioxide (CryO3)......-.-..-------------- . 056 RODE IS Rie - 048 Vanadium sesquioxide (V20O3)....--.------------------ O82) os: 2 oceans |beeeeecees - 026 NiCkOIOHS ORIGO UNIO) UIST SITES SN F ODN ARATE Loa. oF sae - 026 MBNUTHT GIO CDAO) =~ 2 so s.c- 255 snes tance nee Sapceseccs . 055 AUS 3 hl eee acne -10 Sirantium'@xide'(SrO)it ie esis dito sdi ils . 022 ROOOUE cette s. . 043 PrienmnOxiGe Chas) 25555 eo occas ek Bees nceces . 007 AW eee ese -Ol1 100. 000 100. 250 100. 00 100. 000 1. Latest estimate, Clarke and Washington, 1920. ee cate eae Mae an tor pea 4. Clarke, U. S. Geol. Survey Bull. No. 695, p. 28, 1920. In Table I there is given the most recent calculation of the average igneous rock, together with three of the most important of the earlier estimates. As regards No. 1, it is to be noted that the figures for the main constituents, from silica to water, inclusive, were arrived at by dividing the sums total of the various determinations by the whole number of analyses, as all of these constituents were de- termined in all the analyses used. For the minor constituents, from titanium dioxide to lithium oxide, inclusive, the figures given are the means of the sums total of the various constituents divided by the whole number of analyses and also by the number of determinations. The former would presumably give a minimum and too low an average and the latter would probably be too high, while the mean would be probably rather nearer the true figure. This matter has been discussed by Clarke and by me elsewhere, and will be enlarged on further in our joint publication. The figures given here should be considered as provisional, as adequate discussion of their relative merits is not called for here. The figure for fluorine is almost-cer- tainly too high, as are probably those for chromium, barium, and one or two other oxides, while possibly that for carbon dioxide is a trifle too low. From No. 1 it will be seen (and the same is approximately true of all the others) that the first nine oxides (from silica to water, inclusive) constitute 98 per cent of the whole, and that these, with the oxides of titanium, phosphorus, and manganese, make up to- 284 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. gether 99.475 per cent of the crust, leaving only a trifle more than one-half of 1 per cent for all the other oxides. Thus we see that in round numbers silica is the most abun- dant, and constitutes about six-tenths (nearly two-thirds) of the crust; alumina is next—a very poor second—slightly more than one- seventh; then the two iron oxides, together about one-twelfth; lime, about one-twentieth; soda, about one twenty-fifth; magnesia, about one-thirtieth; potash, about one thirty-third; water and titan- ium dioxide, each about one one-hundredth; phosphorus pentoxide, about one three-hundredth, and manganous oxide about one eight- hundredth, while carbon dioxide is about one one-thousandth. Each of the others is notably less than one one-thousandth. It will be observed that in the list, which includes all the constituents that may be commonly determined in really good and complete analyses of igneous rocks, neither copper, lead, tin, zinc, mercury, silver, gold, platinum, arsenic, antimony, nor several other of the elements com- monly used in daily life are represented. The only common metals shown are iron, aluminum, manganese, and nickel. This is a rather important point that will be adverted to later. In order to form an idea of the actual rock that a magma of this average composition would form under normal conditions we must calculate, from the data given by the analysis, the presumable actual mineral composition, or the “mode,’ as it is technically called. There are two general and important conditions controlling the products of solidification that may be considered. The magma may have solidified, at considerable depth, slowly and under great pressure ; or it may have solidified, as a lava flow, on the surface; that is, rapidly and under low pressure. The former would furnish what is called a plutonic rock (as a granite or a gabbro), and the latter an effusive one (as a rhyolite or a basalt) ; and the different conditions of solidification would bring about certain changes in the mineral composition of the resulting rock. Such a calculation leads to the following results, which are to be considered as only approximately correct, as variations in the mode, of slight extent but in different directions, may be brought about by slight variations in the conditions of solidification. As a plutonic rock the magma would form a so-called granodiorite; that is, a rather coarse-grained, holocrystalline rock, much like many granites (and which would be commonly called a rather dark granite), composed of feldspar, quartz, hornblende, or biotite, and very small amounts of magnetite and apatite. If it solidified under surface conditions, the magma would form that most common kind of lava, an andesite, rather fine-grained, light gray or pinkish, and showing small crystals (“ phenocrysts”) of feldspar and either hornblende or pyroxene, with perhaps a little biotite, in a dense “ groundmass.” Under the EARTH’S CRUST-—WASHINGTON. 285 microscope the groundmass would show feldspars, pyroxene (or horn- blende), and possibly a little quartz, with small grains of magnetite and apatite, and with or without glass, according to the rapidity of cooling. Stated in quantitative terms of “modal” or actual minerals, the rocks would have probably the following approximate compositions: Grano- Ande- diorite. | site. SURE RS ae ee ee ee eS Pee eee Ogee eee On eee 11 10 PRERATIONEN SL -CN 1OLUSDAT) oe cece oe ae ee ace See See Soe aa eee eee 47 47 wee LEE? ES G80 GG a Pee eS ee ee ee See 16 18 Hormblendeand biotite: <<. 25... te nk set Slee abn diy aiganeles-ce ee escesc ome 20 | 19 LEWES - oh NE Serene asses sere SA eR ee SE eal el rat ee gg me pan age LUPE GU) 2 Se RSS Sees Pes STP Pence SB ice Sle oa eS eee Oe se ee ere 5 5 USTED Ge 3 2 ee Sa ae cl ea eee ge ap ee Ra, Sete i RE ear arp alate na ts 1 1 It will be seen that, in either case, the average rock would be com- posed entirely of the most common minerals, as is to be expected, with the exceptions of olivine, nephelite, and leucite, which are much less often met with and which, furthermore, are not found in rocks with an excess of silica, as is true of the average rock. Inasmuch as the average rock would have been formed at some depth beneath the sur- face, the average crust may be considered to be a granodiorite, with the general characters and mineralogical composition described briefly above. The fact, however, must not be lost sight of that locally the crustal rock may vary within very wide limits, as will be pointed out later. We are dealing here only with the average of the crust as a whole. We may examine the chemical composition of the earth’s crust in greater detail and, as has been done by Clarke in the papers cited above, reduce the figures of the analysis to the form of the component elements. The results are given in the annexed Table II, there being here presented, not only the elementary constituents of the average rock given in Table I, but in addition data showing the relative abundance of some other of the more important elements that are not usually, or indeed are never, determined in the analyses of rocks. The data for these are taken from estimates by Vogt, De Launay, and Kemp, with’additional data by Clarke and Steiger for a few, and some additions and changes in relative position based on my own studies. An “x” means a digit in the respective decimal place or places. The elements are presented in their order of relative abundance. This estimate is to be regarded as provisional. This average, it must be repeated, does not include the sedimentary rocks or constituents of the hydrosphere or of the atmosphere. Clarke has included these in several of his estimates, and his latest shows that the percentage, on this basis, of oxygen is 50.02, of silicon 25.80, 286 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. of aluminum 7.30, and of the other most abundant elements in simi- larly slightly less amounts than in Table IJ. When thus reckoned chlorine and carbon fall in between titanium and phosphorus, with percentages, respectively, of 0.29 and 0.18, while nitrogen appears between chromium and zirconium with a percentage of 0.03. Leaving these refinements out of consideration here, there are some striking features presented in the table to which attention may be called. The first is the appearance among the abundant elements of some that are usually counted as rare. Among these are especially TABLE II.—The chief elements in the earth’s crust in order of abundance. Ale ROS Oriee: tu Peet ras Meneses 46. 43 24, ‘Coppers 22 Skuse 0. 002 2; SSHiCOn: 2 ein ee PH GLE 25. Cerium, etc_----~~ . 001 yy Nb la aha baa aoe ee 8. 14 2620G Cine ee . OOxx A SRT ROT eee eee ees nee a Pe oe CODME = a . OOxXx Sst Caleium sso 32461 ob ate 3. 63 287) Boron te tne Hagisye . 000x GJ, SOdiams seas 20 bias 2 ee 2. 85 40 Art c\ aoe Sp On gt Ce OD . 000x (CAPOtASSiIM= S60 2 Bele ee 2. 60 BO DOHC 95 te ttipe ek . OOOxx Si) Macnesiumipes 22 2s spa se. aed 2. 09 SL eACSenIC=see ee ee . 00Oxx eS eld Drea a Io Wa a a ariel rere OLS hea sn AO ACLU LUNN ae ees = . 0O000xx TOM Phosphorus’ ==. ee SIBO4 Moa. Lines 2k Sh eth t Ae . O0O00xx AL ELyO rose es! Pesce ee IDM S44 Mereunylee ieee . 0O000xx 12. Manvaneses==.5*4 es is 096; 35. ,Antimony--2., == . 0000xx SAMO RING. 22 ok Se a ee .O77 | 36. Molybdenum_._____ . O0O0Oxx 14a Chilonine= 22 = 225 os ee 5. ODD x ol WILVeRse= ke . 00000xx Tee SUL Me ee 0D loss lune Sten. see . OOO00xx 1GSeB ar im See ee eae ge EEA 0497/39) Bismuth = 22 as . OOOOOxx ta Chromium Se faye es . 0387 | 40. Selenium__---_____ . C00000xx 18s Zirconiume 2S ae 028.4415 Golds oss see eee . 000000xx 19: s EARTH ’S CRUST—WASHINGTON. 291 mides, or iodides, but only seldom and exceptionally do these occur as (primary) silicates, oxides, fluorides, or chlorides. They are fre- quently met with as the “native” elements. There are, it is true, some exceptions to these statements (as with iron, which forms three common sulphides, and with tin which occurs mostly as the oxide) ; but taken broadly, and as applying to the two several groups as a whole, the distinction seems to be valid. The oxides of many of the electropositive petrogenic elements are known to occur as minerals; those, that is, that are stable and are not readily soluble. They include periclase (MgO), corundum (Al,O,), quartz and tridymite (SiO,), rutile (TiO,), ilmenite ((Fe, Ti),.O,), chromite (FeO.Cr,O,), pyrolusite (MnO,) and other oxides of manganese, hematite (Fe,O,) and magnetite (Ie,O,). All of the electropositive petrogenic elements form silicates, and, indeed, they form the overwhelming majority, certainly 99.9 per cent by weight of all known silicates. Besides the simple silicates are borosilicates, fluosilicates, titanosilicates, and zirconosilicates, all of them salts of petrogenic elements. A few sulphosilicates are known, but they are very rare, and there are no known arseno-, antimono-, - seleno-, or tellurosilicates. Fluorides and chlorides of sodium, potassium, ammonium, mag- nesium, calcium, aluminum, cerium, iron, and manganese are known as minerals, and some of them are very common, as NaCl, KCl, and CaF,. On the other hand, neither bromides nor iodides of these elements occur as minerals, though there is an excessively rare cal- cium iodate. Fluorine replaces hydroxyl in several silicates, as in topaz and chondrodite, and it is also present in small amounts in hornblendes and micas, while chlorine is present in small amount in some silicate minerals, as those of the sodalite and scapolite groups. Until we reach vanadium, with atomic weight 51 and atomic number 25, no sulphides occur as minerals, except calcium sulphide, which occurs as a rare mineral (oldhamite) but only in a few meteorites. A very rare vanadium sulphide, found only in one locality, an ex- tremely rare chromium-iron sulphide, occurring only in a few me- teorites, and a rare terrestrial manganese sulphide are known. No arsenides, selenides, or tellurides of these elements, or of those pre- ceding them in atomic number, are known. With the iron group, we find sulphides very common, the sulphides of iron, pyrite, mar- casite, and pyrrhotite, being common minerals, and sulphides of nickel and of iron and nickel, as well as their arsenides, are wide- spread ore minerals. Sulphides and arsenides of cobalt are also fairly common. The sulphide of molybdenum is the only usual min- eral of this element, though a few other minerals containing it (as secondary molybdates) occur. Selenides, tellurides, and antimonides 292 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. of iron are apparently unknown in nature, though of nickel there are some very rare minerals of this character. It will be seen that such compounds (sulphides, arsenides, etc.) of the petrogenic ele- ments are all of those of rather high atomic weight and in the groups of highest valence, especially common in the triad group iron-cobalt- nickel. ; Turning to the metallogenic elements, we find that many of them exist in nature uncombined, notably copper, silver, gold, mercury, arsenic, antimony, bismuth, sulphur, selenium, tellurium, and the metals of the platinum group. Native zinc, lead, tin, and tantalum are also reported, but in some cases doubtfully. As minerals the oxides of these elements either do not exist (as of gold and the platinum metals), are of extreme rarity, or are cer- tainly or almost certainly of secondary origin, as those of copper, mercury, zinc, arsenic, and antimony. Tin oxide, the common ore of this metal (cassiterite), is an apparent exception, but it would seem to be possible that, in some cases at least, 1t is of secondary origin, a sulphide being the primary compound. Primary silicates of the metallogenic metals are very rare. There are none of gold, silver, mercury, thallium, tantalum, tungsten, or the platinum metals. Silicates of copper and zinc are quite common, but are in all cases almost undoubtedly of secondary origin. There are, however, silicates (possibly primary) of tin, lead, and bismuth, but they are mineral rarities, and many mineralogical museums and collections have no specimens of them. No fluorides of any of the metallogenic elements are known as minerals, but insoluble chlorides and oxychlorides of copper, silver, mercury, and lead are known, though rare. On the other hand, as native bromides and iodides we know only those of copper, silver, mercury, and lead—all metailogenic elements. The typical, and by far the most abundant, native compounds of all these metallogenic elements then are the sulphides, arsenides, antimonides, selenides, and tellurides, with the complex sulphosalts. These form the main, and in some cases the only, sources of most of the metals. Indeed, of gold, mercury (except the common sul- phide, the secondary oxide, a chloride, and two doubtful iodides), and thallium (except a rare sulphide), the only native compounds known are selenides and tellurides; and conversely, the only native selenides and tellurides known are of copper (rare), silver, gold, mercury, thallium, lead, and bismuth, except that there is a very rare nickel telluride. Oddly enough, the only native compounds known of the platinum metals are ruthenium sulphide and platinum arsenide, no selenides or tellurides of these being known. Returning to the intermediate interlocking meander zone, it may be well to point out some features that show to which of the two EARTH’S CRUST—WASHINGTON. 293 main groups the several elements there belong, and allude to another feature of interest regarding this part of the table. Rubidium and caesium are known only as silicates, caesium form- ing the rare metasilicate pollucite, and both entering in small amount into other silicates, as beryl, lepidolite, and a few others. Strontium and barium, apart from their sulphates and carbonates of secondary origin, enter only into silicates, a barium silicate forming a member of the feldspar group, and both being the bases in some of the hydrous zeolites. The proper position of yttrium and lanthanum, in group 38, is somewhat uncertain, but they both enter into the com- position of various silicate minerals, and are not known as sulphides, arsenides, etc. The position of zirconium and cerium is quite clear; both form silicates, zircon being especially widespread among gran- itic rocks, and they also enter into the composition of some members of the pyroxene group. The position of columbium (niobium) is also somewhat uncertain, as no silicates of it are known, but it may be basic in some titanates, and its general affinities as to mineral occur- rence would place it almost surely with the petrogenic elements. Closely related to it, and occurring with it almost always, is tantalum, whose true place is uncertain. Minerals containing these two ele- ments, however, are very rarely met with. The researches of Hille- brand+* have shown that molybdenum is very widely distributed among the more silicic igneous rocks, such as granites, so that, even though its most abundant mineral is the sulphide, it should be reck- oned with the petrogenic elements. Of the intermediate metallogenic elements, the positions of copper and silver are ‘unquestionable, as both occur combined most. fre- quently as sulphides and other such minerals. Silver does not occur as a silicate or oxide, but silicates and oxides of copper are not un- common, though these are of secondary origin. The same may be said of zinc and cadmium, the oxide and silicate of zinc being sec- _ ondary. Gallium and indium are found only in zine sulphide (sphalerite), and germanium occurs only as a sulphide with silver and tin. Though tin is most commonly met with as the oxide (as well as a rare silicate), yet sulphides of it are known, so that, in spite of its frequent occurrence as oxide, it is to be reckoned with the metallogenic elements. Arsenic and antimony, as well as selen- ium and tellurium, belong, of course, in this group, as does sulphur, the necessary inclusion of which among the metallogenic elements - carries them somewhat into petrogenic territory, and renders the meander somewhat unsymmetrical toward this end. Bromine and iodine, as we have seen, are only met with in nature in combination with metallogenic elements (except in solution in sea water), so that 1 Hillebrand, W. F., Amer, Jour. Sci., vi, p. 209, 1898. 294 § ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. they may probably be placed with these. The metals of the ruthenium and the platinum groups clearly belong here, because of their occur- rence as metals, and because of the existence of the sulphide of ruthe- nium and the arsenide of platinum as the only native compounds known. On referring to the periodic classification presented in Table ITI, it will be seen that the intermediate, meandered zone, where the petrogenic and the metallogenic elements interlock, shows a very large proportion of elements with atomic weights that are quite far removed from whole numbers, which would imply, as has been sug- gested by Harkins, that this is especially the region of isotopes. Whether this is fortuitous or whether it is (if it be true) connected with the division here suggested of the elements into the petrogenic and the metallogenic groups, is quite unknown, and it is needless here to speculate upon the subject. It should be mentioned that the relations between the positive and the negative elements, and their occurrence in nature as minerals, as set forth above, form an elaboration and an extension of what Clarke has already called attention to,?° namely, “In combination unlike elements seek each other, and yet there appears to be a pref- erence for neighbors rather than for substances that are more re- mote. * * * ‘The elements of high atomic weight appear to seek one another, a tendency which is indicated in many directions, even though it can not be stated in the form of a precise law. The gen- eral rule is evident, but its significance is not so clear.” A possible significance, or rather a possible connection between this rule and the occurrence of the elements, both as to their relative abundance and their mutual relations, in the earth’s crust and below it, may be suggested here, as a somewhat speculative hypothesis. THE INTERIOR OF THE EARTH. The hypothesis (already adverted to), that the interior of the earth is composed, at least in part, of an iron-nickel alloy like that which composes many meteorites, is commonly held. This is based on the mean density of the earth, its rigidity and magnetic character, and the composition of many meteorites, the siderolites, which may be regarded as fragments of a preexisting large body. Following: Charles Darwin and Durocher, who published their view in the first half of the last century, the idea is now held by many that the material composing the interior of the earth is arranged, in a general way, according to relative density,” there 2 Clarke, F. W., “The Data of Geochemistry,” U. S. Geol. Survey, Bull. 330, p. 35, 1908; and Bull. 695, p. 39, 1920. 21 See, for example, Suess, The Face of the Earth (English translation), vol. IV, p. 547, 1909; Daly, Igneous Rocks and Their Origin, pp. 162-168, 1914. le nn to et er ne en BN il | le ee EARTH’S CRUST—WASHINGTON, 295 being a nucleus or core of iron-nickel and possibly other heavy metals, above this a zone of heavy silicate rocks, and at the surface the lighter silicate rocks of the “ crust,’ but presumably passing gradually one into the other, without sharp borders. - Wiechert and Knott have recently shown, through a study of the propagation of earthquake waves, that there is a change in the material, or in the physical properties of the material, at a depth of about 0.5 of the earth’s radius. Still more recently, by labora- tory measurements of the compressibility of rocks, as well as by the study of earthquake waves, Adams and Williamson”? of the Carnegie Geophysical Laboratory, have shown that the much greater density of the interior of the earth can not be accounted for by the compressibility of the materials, whether rocks or metals. They are also led to the conclusion that, while there is segregation of heavier material toward the center, the change is continuous, and not dis- continuous, as is held by Wiechert and Knott. Following the views of Adams and Williamson, and accepting a lower zone of nickel-iron beneath the silicate “ crust,” I would suggest here the idea that the central core, the real nucleus, of the earth is composed of the metallogenic elements, that is, the elements or metals of highest atomic weight, either as “native” metals, or possibly in the form of selenides, tellurides, arsenides, antimonides, bromides, and iodides. Above this would be the nickel- iron zone, and above this the silicate crust. We can not here discuss this suggestion in all its rather complex aspects. But the somewhat intermediate chemical character of the metals of the iron group, with manganese and chromium, is in accord wth the hypothesis, differing as they do from the other petrogenic elements in their occurrence as sulphides and arsenides, in which they resemble the heavier metallogenic elements. Iron is the fourth most abundant element, and if the position of the nickel- iron zone, or a zone of alloy mixed with silicate rocks, were com- paratively near the surface, this would be expected. The occur- rence of iron-bearing basalts at the surface (met with in Greenland, Russia, Spain, and elsewhere) is also in line with this supposition. Again, as on this supposition the true metallogenic elements are most deeply buried, their relative scarcity at the surface is readily understandable. Forming the nuclear core, not only would their total volume be relatively small, but it would also be difficult for them to find their way, even as vaporized or soluble compounds, from the great depths to the surface. The generally low melting points of the ore minerals is also in line with the opinion of Adams *T must express my thanks to my colleagues for permission to mention briefly here some of their conclusions which have not yet been published, 296 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. and Williamson that the deepest interior is not entirely a rigid solid, but more in the nature of a very viscous, thick liquid, which damps the transverse earthquake vibrations. The possible factor of the disintegration of the elements of highest atomic weight must be taken into account, but more can not be said here on this topic. It is of interest to note that this idea, that the elements of higher atomic weights, the metallogenic elements, occupy for the most part the deepest portions of the earth’s interior, is in harmony with Abbot’s view as to the distribution of the elements in the sun.?$ He points out that the elements showing the most intense spectrum lines are those of low atomic weight, with the exception of the negative elements, none of which (with the possible exception of oxygen), for some unknown reason, show solar spectral lines. It is interesting to compare Abbot’s table of intensities (p. 91) with the elements as presented in our Table III of the periodic arrangement. It will be seen that the first 22 elements showing the most intense lines are all terrestrially petrogenic elements, and that (apart from the negative elements) all the terrestrial petrogenic elements are among those that show the more intense lines, with the curious exceptions of glucinum, cerium, and especially potassium, which show but very weak lines. The order is not the same, but the first 10 elements in order of spectral intensity include calcium, iron, hydrogen, sodium, magnesium, silicon, aluminum, and titanium, which, with oxygen, potassium, and phosphorus, are the first 11 elements in order of abundance in the earth’s crust. On the other hand, the metallogenic elements show the least intense or no solar spectrum lines. Thus in Abbot’s intensity tables Nos. 23 to 36 (the last) include in order palladium, copper, zinc, cadmium, germanium, rhodium, silver, tin, and lead. The metals of the platinum group, with tungsten, bismuth, mercury, thallium, and one or two others, give extremely feeble or doubtful lines. As Abbot shows, taking the elements in groups of order of intensity, this diminishes with increase in the mean atomic weight of the group. Abbot explains this distribution, to which the only real excep- tions are cerium, glucinum, and potassium, by the supposition that “the explanation of the decrease of intensities with increasing atomic weights seems to depend on the depth of these gases below the sun’s surface,” and this supposition is confirmed by the spectrum observations of displacements of the lines of various elements due to pressure and those that show in the “flash” spectra during eclipses. The coincidence between the occurrence of the elements in the earth and in the sun, as regards relative abundance and depth, is ap- parently so very close and detailed as to be suggestive of a similar 23 Abbot, C. G., The Sun, 1911, pp. 91, 94, 99, 104, and 252 ff. EARTH’S CRUST—WASHINGTON. 297 arrangement in both bodies. It is also quite in harmony with the general idea of arrangement according to specific gravity or “ grav- itative adjustment.” We may conclude therefore that the metallogenic elements are rare on the earth’s surface and do not show intense spectrum lines in the sun, because they are too deeply buried in both. Connected with this, however, is the difference in the chemical relations already pointed out, the significance of which is as yet problematical. It might be pointed out here that such a theory of the vertical distribution of the elements seems to be opposed to Chamberlin’s hypothesis of the planetesimal origin of the earth, though the matter can not be discussed in this paper. Attention may only be called to the fact, probably very significant in this connection, that the melt- ing points of the oxides and silicates, the typical natural compounds of the petrogenic elements, are much higher than those of the sul- phides and arsenides, the typical natural compounds of the metal- logenic elements. The bearing of this will be discussed elsewhere. Much more might be said of this suggestion of the distribution of the elements of highest atomic weight and greatest density at the center. The idea is not wholly new, having been held specu- latively by others. One might even recall, to pass from science to fiction, that the idea was, in a way, foreshadowed by Jules Verne, who in one of his stories describes a comet or huge meteorite com- posed of telluride of gold. CORRELATION OF THE ELEMENTS. But we have wandered far from our proper topic, the crust of the earth, having reached not only the center of the earth, but the sun, and become enmeshed in somewhat transcendental chemical specula- tion. Let us come back to the surface of the earth. Before returning, however, to the consideration of the actual crust and its rocks, it may be as well to examine briefly a feature of the mutual relations of the elements (for the most part petrogenic), that is shown us by chemical study of the rocks and of the many minerals with which we are acquainted. Since the chemical analysis of rocks and minerals began to assume large proportions, so that sufficient and sufficiently accurate data became available, it has been noticed that certain elements are prone to be found in rocks of certain gen- eral compositions, and also in association with one another in min- erals. In other words, there has been observed a certain correlated distribution of the elements in the earth’s crust—that is, in the rocks and minerals composing it—by which certain of the elements tend to occur together in greatest abundance or most often, while other elements are seldom if ever found along with these. As this is a 298 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. matter of considerable interest and importance from the mining en- gineer’s point of view, several attempts have been made to formulate the relations, and it will be pertinent to give a very brief account of the subject. Among the earliest of the more modern workers to investigate this problem are Vogt, Kemp, and De Launay,** who confined their atten- tion chiefly to whether the various elements considered were most abundant in the more or the less siliceous rocks. The writer pointed out* that “the relations are more complex and are dependent, not so much on the relative amount of silica, as on the relative amounts of other constituents, notably soda, potash, iron, magnesia, or lime.” Such relations of common association are shown, in part among the most abundant constituents of rocks and minerals, and in part among the rarer ones, generally in connection with the more abundant. For the most part, the relations so far ob- served, which may be considered as best established, are confined to the petrogenic elements, as would be expected, but there seem to be similar relations, not yet quite clear, between some of the metallo- genic and the petrogenic elements. Broadly speaking, silica, alumina, soda, and potash tend to go together; thus the rocks that are highest in silica have, in nearly all cases, alumina and the alkali metals as the next most abundant con- stituents. At the same time, the alkali metals, and lime (not iron or magnesia), tend to go with alumina; so that a very large number, and among these the most common, of the silicate minerals are sili- cates of alumina and (or aluminosilicates of) soda, potash, and lime. The iron oxides and magnesia do not show nearly so strong a tend- ency to combine with silica or with alumina. In this connection may be mentioned a tendency toward combination with (or affinity for) silica, which may be expressed thus: K,O0>Na,O>CaO>MgO>FeO. That is, potash will endeavor to take all the silica that it can, so far as is compatible with certain physical conditions, soda next, and so on; iron being the only very abundant element (except silicon) that commonly forms an oxide alone, that is to say, uncombined with silica. This general law or rule, which is based on the most gener- ally observed relations among rock-forming minerals, is the basis of a recently introduced classification of igneous rocks, and it gives * Vogt, J. H. L., Zeits. Prakt. Geol., 1898, p. 326; Kemp, J. F., Ore Deposits, 3d edition, pp. 34-37, 1900; De Launay, L., La Science Géologique, p. 6387, 1906. Cf. also Hillebrand, W. F., U. S. Geol. Survey, Bull. 700, p. 25, 1919; and Clarke, F. W., U. S. Geol. Survey, Bull. 695, p. 18, 1920. 23 Washington, H. S., Trans. Amer. Inst. Min. Eng., p. 751, 1908; Cf. Washington, Manual of the Chemical Analysis of Rocks, 1st edition, p. 14, 1904; 3d edition, p, 17, 1919. EARTH’S CRUST—WASHINGTON. 299 promise of fruitful application in the future. A similar “order of affinity ” as regards alumina is also true of the same elements. Magnesia and the iron oxides tend to go together, or to replace each other in many minerals, which seems to be of much the same import, and these oxides are, as we have seen, generally opposed to soda, potash, and lime. Among the more interesting of such correlations are those of soda and iron on the one hand, and of potash and magnesia on the other, these two pairs tending to go together. This is shown by many min- erals, the details concerning which it is unnecessary to give here, though there may be mentioned the sodic pyroxenes, which contain much iron and little if any magnesia, and the potassic micas, which Na,O KO Fic. 1.—Relation of Na and Fe to K and Mg. generally contain more magnesia than iron along with the potash. Study of many analyses of igneous rocks also brings this relation out very clearly, and it is expressed in the above figure (fig. 1) pub- lished some years ago.** In this the abscissas represent the relative amounts of soda and potash, and the ordinates those of iron oxide and magnesia. The general drift of high soda coincident with high iron, and conversely of high potash with high magnesia (though such rocks are comparatively few), is clearly shown, and, as the data are derived from numerous analyses, and are substantiated by many others more recently made, the general “ drift” may be considered as fairly well established. That the points fall in a rather broad zone, * Washington, H. S., Proc. Natl, Acad. Sci., i, p, 574, 1915, 800 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. instead of along a narrow line, is to be attributed to the complica- tions that may be introduced in such correlations by the presence of silica, lime, and possibly aluminum or titanium. It may be mentioned here, en passant, that, curiously enough, the same correlation between these two pairs of elements, soda and iron, and potassium and magnesium, seems to hold good in the organic world.** ‘This is apparently shown by the following facts: In auto- trophic plant metabolism potash is an essential element, as is also magnesium, in that chlorophyll (which in the leaves acts as the car- bon-transferring substance) is a magnesium salt of a complex or- ganic acid, while sodium and iron are generally toxic toward (at least the higher, gymnospermous and angiospermous) plants. On the other hand, sodium, rather than potassium, is the alkali metal essen- tial to the higher animals, salt being a very necessary article of diet (in part because of its chlorine, and in part because of its sodium, content), and sodium chloride is present in the blood plasma; and at the same time, hemoglobin and its derivatives (which act as oxygen carriers, and are analogous to chlorophyll in plants) are iron salts of organic acids closely related to that of chlorophyll; while, similarly, potassium and magnesium are more toxic toward the higher animals than are the other pair. Let us now pass briefly in review some of the correlations that are shown in igneous rocks by the rarer, and generally petrogenic, ele- ments with the most abundant ones. In the first place, the rocks that are dominantly sodic seem to show the greatest tendency toward the segregation of many of the rarer elements. Thus, lithium, zir- conium, cerium (and some of the other rare earth metals), chlorine and fluorine, and probably glucinum and tin, are found most often, both as components of minerals and in rocks, that are high in soda. Barium seems to be most abundant in those that are high in potash; titanium,”® manganese, vanadium, nickel, and cobalt, in those that are specially high in iron; and chromium and platinum in those that are high in magnesium. Of the proclivities of the more truly metallo- genic elements, as gold, silver, mercury, lead, and zinc, we know little as yet, but further study may indicate such relations, if they exist. It is needless to enlarge here on the bearing of such observations on the practical search for ores and metals, especially those of the rarer kinds, some of which are now coming into prominence, such as tungsten and tantalum for electric lights, and zirconium for refrac- tories. It will be self-evident that a knowledge of the rocks of a region can thus give us a clue as to what elements, or their ores, may be most likely met with, so that, for instance, we would not search for 27 Washington, H. S., Proc. Natl. Acad. Sci., ii, p. 623, 1918. * Titanium also evinces preference for sodium, like its congener zirconium. EARTH’S CRUST—-WASHINGTON. 301 platinum in a region of sodic rocks, but would here look rather for the minerals of cerium, the rare earths, uranium, or tungsten. COMAGMATIC REGIONS. Let us now return to the earth’s crust and endeavor to answer the second question propounded above, namely, whether all large por- tions of the crust are alike in general, or whether they show marked differences; that is, whether the crust is essentially alike or unlike over different areas. Nearly 50 years ago Vogelsang *® pointed out that the igneous rocks of certain districts showed certain textural or mineral characters in common, which served to distinguish them from the rocks of other districts. The same idea was expressed later by Judd,*° and still later by Iddings,** the latter showing that the differences between different districts were referable ultimately to differences in the chemical com- position of the rocks. Such districts were called “ geognostische Bezirke” by Vogelsang, “petrographic provinces” by Judd, the latter name being that in common use, Iddings using the term “ con- sanguinity,” while the writer Jater*? called them “comagmatic regions,” to indicate the idea that the various rocks of a given region are derived from a common magma, by processes of so-called differ- entiation. Into the discussion of differentiation we can not even begin to enter here, though it forms one of the most important and most complex features of petrology, the science of rocks. The proper study of petrographic provinces, or, as we shall here term them, comagmatic regions, is as yet, so to speak, in its infancy. Only a few regions have been described at all adequately from the most general point of view, such as the Christiania region in south- ern Norway, that of central Montana, the Yellowstone Park, and the volcanoes of western Italy; and these descriptions leave much to be desired. Indeed, even the fundamental data for our definition of a comag- matic region are somewhat uncertain and the application of the idea is somewhat loose. ‘Thus, considering the time element, the life of a region may extend over many geological periods, as that of Great Britain from the Silurian to the Tertiary; or it may be confined to but little more than one period, as with the western Italian volcanoes. The areal extent may vary from many thousands of square miles to a few hundreds, though we are beginning to be- lieve that the smaller “regions” are probably to be regarded as but parts of larger ones. The shape of the area may also vary; it may be more or less equilateral, a long zone, either broad or narrow and *® Judd, J. W., Quart. Jour. Geol. Soc., xlii, p. 54, 1886. = Tddings, J. P., Bull. Phil. Soc. Wash., xii, p. 128, 1892. #2 Washington, H. S., Carnegie Inst. Publ., No. 57, p. 5, 1906. 302 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. perhaps forked, or be evident only as small, separate, and apparently structurally unconnected occurrences of similar rocks. Although some of the characters of any given region may be most evidently recognizable by the mineral features, such as the color of the pyroxenes or the peculiarities of the feldspars, yet these are all dependent on the prominent chemical characters of the magma, so that the chemical characters constitute the fundamental basis of dis- tinction and characterization. In order to show the reader how, and in how far, the chemical characters of various portions of the earth’s crust may differ, it will be well to note very briefly some of the best- known comagmatic regions of the earth, stating only their most prominent chemical features and omitting all details. Nv VV Vw” Ny vVv¥ Nay YL YIN Fic. 2.—Comagmatic regions of the United States. In the United States we find a long zone of disconnected areas whose rocks are dominantly sodic. This zone apparently begins in southwest Greenland, appears as a group of very similar small areas in Ontario, Quebec, and New England (the so-called Novanglhan region), appears in New Jersey, Virginia, probably North Carolina, in Arkansas, and finally as several areas in Texas. It is apparently continued south in Tamaulipas in Mexico; and what may be a con- tinuation of it appears in some of the Antilles, in Brazil, and as far south as Paraguay. These areas in the United States are marked solid black in figure 2. The large “ Canadian shield” around Hud- son’s Bay forms another region, which is dominantly calcic (anortho- sites), marked with v’s on the map. Along the Appalachian uplift, and probably extending into Maine, is another region, the rocks of which are characteristically rather sodic granites, though some very EARTH ’S CRUST—WASHINGTON. 303 unusual rocks occur along this zone. This is marked with dashes (—) onthe map. The sodic areas just mentioned may be connected with this. West of the Appalachians we find a few small sporadic occurrences of peculiar rocks, high in potash and magnesia, as in New York, Pennsylvania, Kentucky, and Arkansas, which seem to be distinct from the preceding, and which may represent the great body of magma that underlies this eastern part of the Mississippi Valley. Around Lake Superior, in Minnesota, Wisconsin, and Michi- gan, and probably extending into Canada to the north, is an area of igneous rocks that are low in silica but high in lime and iron oxides. To the last feature is due the importance of this region for its very abundant iron ores. It is marked with x’s on the map. In the southern part of the Mississippi Valley, about the Ozark uplift, are some small and as yet little-studied occurrences of granitic rocks, which seem to form a distinct region. West of the Mississippi Valley the comagmatic relations are more complex, as are the geological structures, but we can distinguish some fairly well-defined comagmatic regions. One of the most clearly marked is that which extends from, and possibly beyond, the Canadian border through central Montana, where it is represented by several volcanic centers described by Pirsson and others, into Wyoming, and with patches that probably represent it in eastern Colorado. These rocks are characterized by decidedly high alkalies, and with potash generally dominating soda. The areas are marked by +’s on the map. Covering the great plateau of Colorado, Utah, and Nevada, with parts of Idaho and Wyoming (including the Yel- lowstone Park) and probably in northern New Mexico and Arizona, is a large and complex region, the rocks of which are decidedly of average composition, distinctly high in silica, moderate lime and alkalies, and low iron and magnesia. North, west, and south of this is a rather ill-defined region, whose rocks are similar but somewhat more calcic. The first is distinguished by small circles and the latter by dots on the map. These regions need further study, and it is doubtful if they should be treated separately. In southern Idaho and in Washington and Oregon are the very extensive flow basalts of the Snake and Columbia Rivers, high in lime and iron oxides, which resemble chemically the rocks of the Lake Superior region and which are marked similarly on the map. The true relationship of these te the surrounding regions is doubtful. Along the Pacific coast, chiefly in California; but extending to the north about as far as Puget Sound, there are indications of a nar- row zone of decidedly sodic but rather highly silicic rocks. This may extend south along the west coast of Mexico, and may there be connected with the origin of the jadeite objects found in that 304 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. country, the exact provenance of which is unknown. Thus may petrology aid archaeology. The long chain of the Andean volcanoes seems to form a continua- tion of the main Cordilleran region, which is continued northward along the Aleutian volcanoes, and thence southward, along the west coast of the Pacific, through the volcanoes of Kamchatka, Japan, and the Philippines, and so on to the Dutch East Indies. This so- called “Circle of Fire” surrounds a large area, that of the Pacific Islands, whose rocks are dominantly basaltic—that is, low in silica and alkalies, and high in lime, magnesia, and iron, associated here ~ and there with occurrences of alkalic rocks. In Europe the various comagmatic regions are so numerous, so complex, and so little known from this point of view, that only a few need be mentioned. There is the extensive, though broken-up, region that. embraces the British Islands and their outliers, with Iceland, eastern Greenland, Jan Mayen, Spitzbergen, and Nova Zembla, the rocks of which are dominantly basaltic. The highly sodic Chris- tiania region in southern Norway has been well studied by Brégger, as has the calcic Bergen region by Vogt. Germany and Austria are filled with a complex of different regions, the relations of which are not yet clear, but. which seem to be either dominantly sodic, as that of Bohemia, or with basaltic tendencies. The Alps and the Tyrol form a central region of prevailingly granitic rocks which differ markedly from the various and different regions that surround them; this is a point to which we shall recur. In Italy is the so-called Roman comagmatic region, embracing the volcanoes along the west coast from Bolsena to Vesuvius, the rocks of which are decidedly unusual in their very high potash, with considerable lime. A zone of distinctly sodic rocks appears to extend from southern irance and eastern Spain, down Corsica and Sardinia, through the island of Pantelleria, into Tripoli. Hence, by way of Kordofan, this region is possibly connected with the highly sodic one that stretches from Abyssinia down the Ethiopian Rift Valley, in East Africa, and which branches northwardly along the Red Sea and Arabia as far as Syria. At the east end of the Mediterranean, on the other hand, is a region embracing Greece and the Balkan Peninsula, the Archipelago, and western Asia Minor, whose rocks resemble very closely those of the Colorado plateau and of the Andes volcanoes. We could go on thus over the surface of the earth, so far as its rocks are sufficiently well known chemically. Unfortunately, this is not the case with many large, and otherwise thoroughly studied, areas or regions, such, as, for instance, the Greater Antilles, Cuba, Jamaica, Haiti, and Porto Rico. But this very rapid sketch will serve to give the reader some idea of how diversified, chemically, are the different portions of the earth’s surface. EARTH’S CRUST—WASHINGTON. 305 It has been suggested by several prominent petrologists** that the comagmatic regions may be referred genetically to two large types of magma or “provinces,” called “alkaline” and “subalkaline” by Iddings, or “Atlantic” and “ Pacific” by Becke. The latter goes so far as to attempt to ascribe all the comagmatic regions to two areas, the one dominantly alkalic and surrounding the Atlantic Ocean, and the other more calcic and surrounding the Pacific. Harker, further- more, would connect these two main types of comagmatic region with two main types of crustal movement or stress, such as are recognized by Suess, which give rise to different types of coast, mountain forma- tion, etc. In the opinion of the writer such recognition of but two types is not consonant with what we know of the general distribution of the igneous rocks. The whole subject is very complex, far too much so for proper discussion here, and the data available seem to the writer to be inadequate for very broad generalizations at present. CHEMICAL COMPOSITION AND ROCK DENSITIES. The above outline of comagmatic regions leads us to the considera- tion of two subjects with which we may close this sketch of the chem- istry of the earth’s crust; that is, the relation between the chemical composition of rocks and their density, and that between these and the theory of isostasy. In the preceding pages we have considered igneous rocks almost only from the chemical point of view. As we know, however, they are actually aggregates of definite chemical compounds, minerals, mostly silicates. Furthermore, we know that magmas of the same general chemical composition may crystallize as diverse aggregates of differ- ent minerals, according to the conditions that obtain during solidifica- tion. If we know the chemical compositions of the various rock-form- ing minerals, the quantitative mineral composition may be readily calculated from the chemical analysis of the rock. But from what has just been said, it is evident that the particular mineral aggregate to be calculated will depend on the conditions controlling solidification. It is also obvious that if we know the mineral composition and the densities (specific gravities) of the minerals, that of the rock as a whole may be readily calculated. In the conception and elaboration of a system of classification of igneous rocks that was proposed some years ago by some American petrologists, the chemical composition of igneous rocks was regarded as their most fundamental character, and therefore that on which their classification was primarily based. But, in order to recognize the fact %3Hor some general discussion of this and related topics, the reader is referred to Har- ker, The Natural History of Igneous Rocks; Iddings, Igneous Rocks, Vol. I; and Daly, Ig- neous Rocks and Their Origin. 42803 °—22——20 306 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. that they are actually mineral aggregates and so as to be able to com- pare them one with another on this basis, in spite of the various pos- sibilities as to mineral composition introduced by the varying condi- tions of solidification, the chemical composition shown by analysis is calculated in terms of mineral composition according to one uniform system; that is, one general assumption as to the minerals that are formed, or may be formed, from the particular magma. In this way, all igneous rocks are comparable and classifiable inter se, both chemi- cally and mineralogically. The details of the procedure and the re- sults of this system of classification can not be gone into here, but may be looked for elsewhere.** It will suffice here to say that the general principles which are considered basal are the so-called “ affinities” of the various basic oxides for, first, silica, and, second, alumina, which have been given on a previous page and which are deduced from the general knowledge of rock minerals. Carried out along the lines so laid down the results of the calculation from the data of the chemical analysis give a mineral composition which, although ideal, cor- responds with the actual mineral composition in the great majority of cases. Some years ago Iddings** pointed out that the density (specific gravity) of a rock as calculated from the calculated mineral composi- tion on the assumption that the rock is holocrystalline, corresponds very closely with the actual density. This fact is of great interest; partly because of its justification of the fundamental basis of the classification, and also because it thus furnishes a uniform means of comparing the densities, not only of particular rocks, but of the average rocks of different regions, and quite irrespective of such factors as those due to porosity or the presence of glass. Following the suggestion of Iddings, I have calculated the average densities of the continents, the ocean floors (represented by the lavas of the vol- canic islands in the Pacific and the Atlantic), and of the igneous rocks of various countries and comagmatic regions, whose average chemical compositions were calculated by Doctor Clarke from the data in Professional Paper 99. % Cross, Iddings, Pirsson, and Washington, A Quantitative Classification of Igneous Rocks, Chicago, 1903; Washington, H. S., U. S. Geol. Survey, Prof. Paper No. 99, 1917. There is a considerable literature on this and other systems of the classification of rocks. 85 [ddings, J. P., The Problem of Volcanism, p. 128, 1914. For a later and more detailed statement, see Iddings, Amer. Jour. Sci. (4), xlix, p. 363, 1920. EARTH’S CRUST—WASHINGTON. 8307 Taste 1V.—Average compositions of continents and ocean floors. 1 2 3 4 5 6 2 8 9 10 59.09 | 60.01 | 61.09 | 59.66] 61.77] 58.20 | 59.99] 58.56 | 50.63 50. 06 15.35 | 15.71] 15.13] 15.07] 15.45] 15.31 | 14.69] 16.79 | 15.82 15. 51 3.08 2.87 3. 02 3.16 3.16 3. 52 2. 59 4.00 4. 44 3.88 3. 80 3. 66 3. 29 3. 66 2.75 3. 74 4. 40 5. 33 5. 79 6. 23 3.49 3.15 3. 46 3.60 2.63 3.51 3.75 4. 66 5.79 6.62 5. 08 4.79 4. 86 4. 96 4.49 5.10 5. 02 7.57 7. 36 7.99 3. 84 3. 89 4.07 3.02 4.09 4.84 3.49 3. 57 4.27 4.00 3.13 3.06 2.68 3.39 3. 22 3.28 3.02 2.32 2.31 2.10 1.14 1.01 1.04 1.24 1.23 1.26 1.19 -93 1.47 1.16 1.05 1.01 - 56 83 - 68 84 1.01 87 1.63 1.96 30 26 Spill 23 -12 20 26 aU 43 +25 -12 -10 12 08 -10 -07 -15 03 - 04 -15 -48 -19 -16 -14 04 17 | WO sims os -07 - 08 100.00 | 99.71 | 99.59) 99.70] 99.75 | 100.14 | 99.70] 99.80 | 100.05 |. 100.00 Earth (5159 analyses). Density=2.77. Elevation =+2,252 feet. North America (1709 analyses). Density=2.75. Elevation=1,888 feet. South America (138 analyses). Density=2.72. Elevation=2,078 feet. Europe (1985 analyses). Density=2.75. Elevation=939 feet. Asia (114analyses). Density=2.72. Elevation=3,189 feet. Africa (223 analyses). Density=2.77. Elevation=2,021 feet. . Australia (287 analyses). Density=2.79. Elevation= 805 feet. . Antarctica (103 analyses). Density=2.79. Elevation=? feet. . Atlantic floor (56 analyses). Density=2.85. Depth = —13,500 feet. . Pacific floor (72 analyses). Density=2.89. Depth = —14,820 feet. SOON PoP i Before we discuss the densities it will be well to examine the aver- age chemical compositions of the different continents and ocean floors, the data for which are given in Table IV. It will be seen that they vary considerably the one from the other, as well as from the general average of the earth’s crust. Taking, for example, silica, the most abundant constituent, its percentages for North and South America, and especially for Asia, are decidedly above that of the earth’s crust as a whole, while those for Europe and Australia are only slightly above this. On the other hand, the silica percentages for Africa and Antarctica, and still more for the Atlantic and the Pacific floors, are very notably lower.*® There is little difference, comparatively, in the figures for alumina, the alkalies, and the minor constituents, but those for the iron oxides, magnesia, and lime are distinctly lower in those cases where silica is higher and higher where this is lower. The continental and oceanic averages shown above represent, in fact, different comagmatic regions on a large scale, but in concise form. Though the data for some of them—as Asia, South America, Africa, and Antarctica—are not numerous enough to be wholly satis- factory, yet there would seem to be no valid reason for doubting that, taken as representing broadly the general chemical composi- tions of the larger structural divisions of the earth’s surface, they may safely be assumed to give us a fairly trustworthy idea of the relations between them. . In any case, they are the only large body of data that we have available, so let us use them vrovisionally and see to what results their consideration may lead. Before doing this, however, it will be as well to devote a few words to the average density of the crust as a whole, as this is an important 86 Tf the analyses of the rarer rocks are disregarded, the density of the Atlantic floor is about 8.05 and that of the Pacific is about 3.10. 308 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. factor in the consideration of isostasy, to be taken up later. It will be seen from the table that the average density of the crust is cal- culated, from the average chemical composition, to be 2.77. An average might be arrived at by considering all the determinations of specific gravity of rock specimens that have been made by the ordinary physical methods, and that are found abundantly in the literature. An average thus arrived at would seem to suffer from several disturbing factors that are eliminated by the method based on the chemical averages. Thus it would include the densities of many lavas that are more or less glassy, which are decidedly lighter than holocrystalline rocks, and which, furthermore, are surficial rocks, not found at any considerable depth beneath the surface. It would also be seriously affected by the porosity of the surface rock specimens; and at great depths this must be very largely or wholly done away with by the pressure of the superincumbent crust, as shown by Van Hise and others. On the other hand, however, the density determinations are probably more equably distributed among the various kinds of rocks than are the chemical analyses, which may reasonably be expected to include a possibly undue proportion of “interesting ” and rarer types of rocks, as has been mentioned. It is impossible at present to evaluate the relative influences of these several factors, but I might incidentally express my surprise that such a simple means of arriving at an estimate of the average density of the rocks of the earth’s crust as is here suggested does not seem yet to have been attempted—at least nothing seems to have been published on the subject. An estimation that I am now making along this line is not yet complete enough for publication in this paper, but will be given later elsewhere. On the whole, after due consideration of the several factors in- volved, I am inclined to put much greater weight on the final result arrived at from the averages of the chemical compositions. This, also, is subject to certain possible corrections in the future. It would seem to be probable that it is somewhat too high, as it does not include any, or at least a proportionate, number of analyses of many large areas which are almost certainly generally granitic and there- fore relatively light. This applies to the interiors of Asia, South America, Australia, and probably Africa, to mention the larger divi- sions, and also to smaller ones, such as Spain, Egypt, South Africa, the Greater Antilles, and others. It is impossible now to estimate the magnitude of this correction. On the other hand, if we are dealing with the rocks of the crust to any (humanly) considerable depth, such as the 10 miles assumed by Clarke, and which might justly be placed at 20 or more, we meet with the possibility of a correction in the other direction; that is, toward a higher density, This conclusion is based on the ideas of EARTH’S CRUST—WASHINGTON, 309 Daly and others as to the existence of a basaltic substratum beneath the dominantly granitic outer shell, that is brought about by “ gravi- tative adjustment.” Balancing up these conflicting factors, I am inclined to place the average density of the crust at about 2.75, at least for the uppermost shell, while that of 2.80 would probably be nearer the truth for the average of any considerable depth, such as 20 or more miles. In the present state of our ignorance and the paucity of our data, however, it would seem to be wisest to accept the figure given by the many analyses available and assume a density of 2.77 as that of the earth’s crust. Australia Antartic Atlantic Pacitie & S$ Ss Rey Asia Africa ie eet ae - Sts au Densivies ensity SEY EE Se 270 Average SEEPLET Spec. Vol +4000, |__| adi ea Seat ap fi) 5 pei LIN Fic. 3.—Elevations and densities of the continents. Geodesists have assumed a density of 2.67 for their studies of isostasy, as will be noted elsewhere. They take into their calcula- tions, however, only the extremely superficial layers, including such strata as soil and light sedimentary deposits. As will be mentioned later, I am inclined to think that this estimate is much too small and that the basis of their calculations should be a considerable higher density. That of 2.77, here assumed, or possibly better, 2.75, would seem to be the best available under the circumstances. + 2000 Sea Level - 4000 -8000 ROCK DENSITIES AND ELEVATIONS, With the analyses in Table IV are given the calculated densities and the average elevations of the continents and the depths of the ocean floors referred to sea level. The general relations are graphi- cally expressed in figure 3. The lowest graph is that of elevations, the uppermost is that of densities, while the intermediate one is that of specific volumes, or reciprocals of the densities, which serves 310 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. better to bring out the parallelism. The sequence of the continents and oceans is arbitrary. It will be evident from the Table IV and from the graphs that there is a close relation between the average densities of the conti- nental masses and of the ocean floors and their average elevations or depressions. They stand in inverse relation to each other; that is, the higher portions of the earth’s crust are composed of the lighter rocks and the lower portions of the heavier. When it is remembered that these relations are shown by a very considerable number of averages based on a very large number of trustworthy analyses (the largest so far available) from all parts of the earth, the correspond- ences are too striking to be explicable by an appeal to chance or coincidence. This is even more obvious when we come to consider the relations in greater detail, as we shall do presently. In discussing this subject it must be kept in mind that we are dealing with the averages of large areas and of many analyses, so that small and local details are lost. Thus a number of volcanoes show flows of heavy basalt covering lower flows or inner cores of lighter rhyolite or andesite. Again, it is not uncommon to find sheets of heavy basalt capping plateaus or forming the summits of their mountain remnants. But such apparent contradictions to the general law shown above are but local and minor details, insignificant as compared with the immeasurably greater masses of which they form but topographic surface features. The general relations between rock density and elevation are also, and possibly more strikingly, seen when they are presented in greater detail, as is done in figures 4 and 5.°7_ These are based on the average densities calculated from the average chemical compositions of the rocks of different countries and regions, as determined by Doctor Clarke. These represent the. general elevations and corresponding average densities along two zones around the earth, the one roughly between latitude 40° and 50° N. and the other between latitude 10° and 20° S. It is to be understood that the graphs are much generalized, representing average densities and elevations, so that there is little detail. The outer circle is that of sea level and the irregular line that crosses it is a generalized graph of the land elevations and the ocean depths. Though the positions in longitude are approximately cor- rect, the vertical scale of these is not that of the earth as represented by the sea-level circle, but the heights and depths are very greatly exaggerated, otherwise the differences would not be perceptible in any practicable illustration. The portions of the land surface are, how- ever, all drawn to the same (exaggerated) vertical scale, while that of the ocean depths is one-half of this. The elevations shown for 8 For the suggestion of this method of presentation I am indebted to Dr. L. H. Adams, ef the Geophysical Laboratory, EARTH ’S CRUST—WASHINGTON. 811 the interiors of South America, Africa, and Australia are the conti- nental elevation averages as given by Murray. The inner circle is that of the average specific volume (44,=0.361), and the inner broken line, made up of arcs, is that of the average specific volumes of the portions of the earth’s crust radially above the successive small arcs. Specific volumes (the reciprocals of the densi- ties) are used instead of densities because the relations are brought out more clearly and immediately by the parallelism with the eleva- tion graph shown by the former. The arc portions of the specific volume graphs in solid lines are the ascertained averages, while por- tions that are unknown, because of the absence of exposures of igneous rocks or for other reasons, are indicated by dotted arcs, their radial distance being roughly estimated, so far as is possible. These various arcs are connected by radial dotted lines. The center of the circles is the locus of the axis, seen from the North Pole, and is at the same time the zero point for the two graphs.. The graphs show the correspondence between elevation and spe- cific volume so clearly that it is scarcely necessary to go into a detailed description; yet a brief summary of the northern zone may be of interest. This represents the conditions around a zone which ex- tends roughly between 40° and 50° north latitude, varying somewhat north or south so as to include available data and complete the circle. The data on which the graphs are based are given in Table V. TaBLe V.—Average densities, specific volumes, and elevations. Specific Average Density. volumes. | elevation. Feet. TOD Van bs py a lh STE Ot SS HS Pe 2.77 0. 361 +2, 252 PVE MBAINETICH. 55-5 nint cama aebtte Mest dees eStap conn Notesasctecn 2.75 . 36 1, 888 RIL OCIL AL OSs < Aes Sade cate caccte nee s ni aos PASS une fee nc er rwe 2.75 . 364 2, 500 Gp . 368 2,078 2.75 . 364 939 2. 72 . 368 3, 189 2.77 . 361 2, 021 2.79 . 308 805 2.79 . 308 ? 2. 85 351 —12, 800 2. 89 346 | —15, 400 California 2. 742 . 365 + 3,000 open and Washington.. 2. 773 361 2, 500 Utah and Nevada........ es 2. 717 368 6, 000 GIOTAdO Sh. oc cpe sso eccese3 2. 735 . 366 7, 000 RE ZE RAT OCUGI 2 Eee RAO EMSS CNTE Ode cue Soe Se gusbidedaoeademed 2.728 367 2, 000 Michigan, Wisconsin, Minnesota 2. 803 . 357 1, 000 ty achia ( Pennsylvania to Georgia) 2,749 . 364 2, 000 ew England and New York 2. 759 . 362 750 PEMOUNESEIUAIN oct See sae. Se ec Nee ce ene sacs ee claclo Cetin se ccte Se ceee ae 3. 041 329 300 Se ee 2 ee eee = eee: Pe eee ey eee 2. 867 . 349 600 SREB Sere See Sean ae ee ie) Set a ctaation scartemoeie ce cicdie os 2.772 . 361 800 Bwmlizeriand and Tyrol. fe Be ES ected accent - cad: gooees < 2. 729 . 366 5, 000 JA UIRLATIDEL SCT Sg ge Ble pn flea tg eg se hae eg Ra SE 2. 784 399 2, 000? Urals and Caucasus... 2. 829 . 353 2, 000+- Pamir 3. sess 2. 72— . 368+ 13, 000 PRpARS 385 0 Meco. 2,723 - 367 1, 420 ZONE 10°-20° SOUTH LATITUDE ae AY pe RL ee eer Soe ee erent | ae A a Oe 2.717 368 6, 000? UD S)n Ede Py ees eR ai ah SS ec eet Ue te 2.745 . 364 2, 500? Africa (east and west).........- En aie 2.77 . 361 2,021 Madagascar and Reunion... aaeue oe 2. 830 . 353 New Zealand..............- 2.749 . 364 2,134 1 For the hypsometric data I have consulted Murray, Scot, Geog. Mag. iv, pp. 1-29, 1888; Gannett, U.S. Geol. Survey, Am. Rep. 13, ii, d. pp. 283-289, 1892; Bull. No. 274, 1906; and other authorities. 312 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. Let us take a little journey around the earth along the northern zone. (Fig. 4.) Beginning at the Pacific coast, the land gradually rises across California to the high plateau of Nevada and Utah, cul- minating in Colorado. Thence it slopes gradually down, across the Great Plains (Kansas), to the Mississippi Valley. Along this slope practically no igneous rocks are met with, except for sporadic and little-studied occurrences in the Ozark Ridge. The slight rise seen in the Mississippi Basin is the level of the rocks of the Lake Superior region (Minnesota, Wisconsin, Michigan). East of this (Kentucky) few igneous rocks are known except those mentioned above, and the land slopes gradually up to the Appalachian Ridge, Lat.40~50°N L Vales, States x yi? do NS G Vich AE, ogo’ vee a ole Ne oe da Gn SY Kor we por Japa Pk $ Southern Russia China Ural Mts. Pamirs. Fic. 4.—Surface relief and specific volume. and east of this, across New England in the graph, descends to sea level. The floor of the North Atlantic is rendered very summarily, and the Azores and Iceland are about our only source of information as _ to the composition of its floor along this zone. On the east coast of the Atlantic the British Isles rise to but a small height (on the average) above its surface. The average elevation of France is‘slightly higher; that of Germany (which is inserted in the zone a little out of latitude) is still somewhat higher, and thus we come to Switzerland and the Tyrol, the culminating portion of Europe. To the east of this, with an average elevation slightly greater than that of Germany, lies’ EARTH’S CRUST—WASHINGTON. 313 Austria-Hungary, and then to the east the low-lying plains of south Russia. East of these are the Ural Mountains, and then (bending somewhat southerly) we pass through Turkestan and Persia, and reach the very high Pamirs, the “roof of the world.” Thence the surface slopes down across China, rises again in Japan, and again drops to the depths of the Pacific Ocean. Let us now see how the rock densities, or rather the rock specific volumes, correspond with the elevations. This inner graph, it is to be remembered, represents the specific volumes, that is the reciprocals of the densities, so that it is inverse to what the graph of the den- sities would be—that is, the heavier the average rock the nearer to the center it is on this graph, and the lighter the farther away. Starting with California, we find its specific volume arc above the average, and that of Nevada-Utah to the east still higher. The average of Colorado is a trifle lower, though the elevation is higher, and this is one of the very few notable exceptions to the general rule. We are ignorant of the igneous rocks beneath Kansas; they are in- dicated as but a little above the average, which is probably not very far wrong. ‘There is a decided rise below the Ozark Ridge (with its greater elevation), while the arc below the Mississippi Valley is represented by the small arc for the Lake Superior rocks, which are high in iron oxides and with high average density. Of the rocks below “Kentucky” (east of the Mississippi) we know little, but the Lake Superior arc is continued here because of the sporadic oc- currences of some heavy peridotites in Kentucky mentioned above. The graph rises sharply in the arc beneath the Appalachians, falling again beneath New England, which is distinctly below the average. With the Atlantic floor we descend to an arc beneath it that is well toward the center, as its rocks are of very high density. The arc for Great Britain is scarcely above that of the Atlantic floor, that of France distinctly higher, though still below the average, while the arc below Germany is just above the average.** With the Alpine and Tyrol arc we rise well above the average and here, just as in the elevation graph, we reach the culminating point of Europe. The arc beneath southern Russia (dotted) is placed at a level but slightly different from that of Great Britain, because, though igneous rocks are rare in this district, there are occurrences in Volhynia of very heavy iron-bearing basalts. The arc beneath the Urals is but slightly above this, corresponding with the heavy rocks of these mountains which, it is to be remembered, are low and little more than large %8 The specific volume are for Germany should be but little above that of France to corre- spond with the relative elevations ; it appears to be much higher because very many of the German analyses of the heavier rocks (diabases, basalts, etc.), the analysis of which is most liable to error, are of very poor quality, and are therefore omitted, 314 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. hills. Of the rocks of Persia and Turkestan we know but little, so the arc below this is dotted and slopes up to that beneath the Pamirs, or central Asia. Here again our knowledge is far from precise, so that the are is dotted and is placed at the level of that of the average of Asia, though it should probably be somewhat higher. Analyses of Chinese rocks are few, but they would seem to be in general like those of the Pamirs, though a trifle heavier. The Japan arc is above that of China, and east of this we reach the wide arc beneath the Pacific Ocean—the lowest of all, just as its rocks are the heaviest. After the journey around the world that we have just made in the Northern Hemisphere it seems quite needless to describe that in the Southern. (Fig. 5.) The reader may follow the correspondence Lat 10%20°S Andes Indian Ocean Fig. 5.—Surface relief and specific volume. for himself, remembering that the available data along this zone are far less numerous than along the northern; though we have good knowledge of the rocks of Madagascar,® Eastern Australia and New Zealand, and fair knowledge of those of the Andes and western Africa and the Ethiopian Rift Valley. ROCK DENSITIES AND ISOSTASY. We come now to the final section of our study of the earth’s crust, the application of the data just presented to an important theory regarding the stability conditions of the crust, the theory of isostasy. %2'The average density of Madagascar is unquestionably less than that here given, as is shown by the many more analyses now available. The density 2.83 represents more prop- erly that of Reunion, and thus that of the floor of the Indian Ocean. 4 EARTH’S CRUST—WASHINGTON. 315 As far back as 1852 J. H. Pratt suggested that there was a defi- ciency of gravity beneath the Himalaya Mountains, basing this on the anomalous behavior of the plumb bob.*? He also propounded the view that the heavier portions of the earth’s surface were sinking. Later, Dutton** first clearly expounded the idea that the various portions of the earth’s surface, being laterally unlike or heteroge- neous, are in a delicately balanced condition of equilibrium, so that the lighter portions (those of less specific gravity) tend to rise and the heavier (those of greater specific gravity) tend to sink, the various portions thus balancing each other. This theory, later called isostasy (meaning equal standing), was taken up by Hay- ford, and he and William Bowie, of the United States Coast and Geodetic Survey, and others,*? have done much to develop it, espe- cially as regards its application to gravity problems. While still in dispute, especially as to some details, it is now a well-recognized and generally accepted geodetic theory. Tt will be well to quote in part Hayford’s definition #* of isostasy. Assuming a condition of lateral heterogeneity, he says: Different portions of the same horizontal stratum may have somewhat dif- ferent densities, and the actual surface of the earth will be a slight departure from the ellipsoid of revolution in the sense that above each region of deficient density there will be a bulge or bump on the ellipsoid and above each region of excessive density there will be a hollow [depression], relatively speaking. The bumps on this supposed earth will be the mountains, the plateaus, the continents, and the hollows [depressions] will be the oceans. The excess of material represented by that portion of the continent which is above sea level will be compensated for by a defect of density in the underlying material. The continents will be floated, so to speak, because they are composed of rela- tively light material, and, similarly, the floor of the ocean on this supposed earth [will] be depressed because it is composed of unusually dense material. This particular condition of approximate equilibrium has been given the name “ isostasy.” As has been noted above, in the case of northern India it has long been known, from pendulum determinations of gravity, that in many portions of the earth the observed force of gravity does not correspond with that calculated from the form of the geoid, after making corrections for the influence of topography (such as the attraction of near-by mountain masses) and for the elevation of the station above sea level. Thus, it has long been known that gravity is on the whole greater over the ocean than over land areas, and this has naturally been connected with the fact that the rocks of oceanic islands are mostly basaltic and therefore heavy. Cf. Iddings, J. P., The Problem of Volcanism, p. 64, 1914. “ Dutton, C. E., Bull. Phil. Soc. Wash., xi, p. 51, 1889. “For some references, see Iddings, op. cit., p, 65, “ Hayford, J. F., The Figure of the Earth, p. 66, 1909; Cf. Bowie, W., U. S. Coast and Geodetic Survey, Special Publication No, 40, p. 7, 1917. 316 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. These departures from the normal are known as “anomalies.” They may be either positive, when the gravity is above the normal, or negative, when it is below. The anomalies have been studied with great care and in great detail, especially by Hayford and Bowie in the area of the United States, who have invoked the theory of isostasy to account for them. This explanation is satis- factory to a very large extent, but, as Iddings says, “ There remain anomalies of, density which need to be accounted for.” On the whole, however, it appears that the theory of isostasy “obtains for the major features of the earth’s surface.” It may be suggested here (though the matter can not be discussed) that the discrepancies may be due, in part at least, to the fact that the geodesists have taken account of the rock densities only of those portions very near the surface, mostly soils and sedimentary rocks, and have neglected the deeper-lying portions. The average density assumed by geodesists for the surface rocks is 2.67, while, as we have seen, that of the igneous rocks of the earth’s crust is 2.77 or 2.75. It will be seen that the idea of the continental masses being com- posed of light material while the ocean floors are of heavy is by no means new. Up to the present, however, there has been no quanti- tative verification of this, except for the few figures covering limited areas given by Iddings. ‘The data given above, with the graphs, therefore, are of special interest as furnishing a first approximation to a knowledge of the actual densities of the various portions of the earth’s crust. It is evident that they are, on the whole, and even in considerable detail, quite in harmony with the theory of isostasy. Indeed, based, as these figures are, on a large number of data (the largest by far yet available) from all parts of the earth, and showing such a complete harmony between average density and average elevation everywhere, they may fairly be said to be more than coincidental, and to constitute almost a conclusive proof of the gen- eral validity of the theory of isostasy. One further point of agreement may be mentioned. In figure 6 is given a map of the United States reproduced by Barrell ** from Bowie, showing the distribution of the gravity anomalies over the United States. Let us compare this with the description of the comagmatic regions of the United States (fig. 2). In figure 6 the dotted areas are those of positive anomaly (excess gravity), while those not dotted are of negative anomaly (deficient gravity). In the extreme northeast is a small area of positive anomaly about the Adirondacks, which corresponds with the small comagmatic out- lier there of the Canadian Shield, of which the rocks are above the average in density. The greater part of Maine, with its “Barrell, J., Jour. Geol, xxii, p. 153, 1914. EARTH ’S CRUST—WASHINGTON. $17 granites, of low specific gravity, shows negative anomaly, and this area is continued down along the Appalachian region, the rocks of which are of general low density. The small areas of posi- tive anomaly in eastern Massachusetts, Connecticut, and New Jersey may probably be connected with the extensive Triassic flows of heavy diabase and basalt which are so common here. Around the Lake Superior region we find an area of very high positive anomaly, which corresponds with the high density of the rocks of this region. On the other hand, in the Missouri-Arkansas-Oklahoma region is an area of pronounced negative anomaly, which corresponds with the low density of the region of the Ozark uplift. East of this, in Kentucky and Tennessee, is an area of somewhat high positive Oat 20 BAC SS $50 ay \, , LOTS we. J, a } "Ab, 02 ve Hho 4 t~a te O29 4 Ron 7, ME: a oy “7\ 0055 5 Ko~/ Ss ae i * AL \F oo R\ PIS SUT HO? = 21058 100° od, _ 30° Fie. 6.—Dotted portions: Areas of positive anomaly, excess of mass. Due to surface too high or density of upper crust above mean. Blank portions: Areas of negative anomaly, deficiency of mass. Due to surface too low or density of upper crust below mean, Gray- ity anomalies in the United States. anomaly, and this is in harmony with the supposition made above that the rocks underlying this area are decidedly heavy. Toward the west the relations become more complex, just as is the geological structure and as are the comagmatic relations. We can not here go into details, which are reserved for a future publication, but the general area of negative anomaly covering the Colorado and Nevada-Utah plateau, consonant with the light rocks here, may be pointed out, as also the small area of high positive anomaly in Wash- ington and Oregon, which may be connected with the very extensive flows of heavy basalt of the Snake and Columbia Rivers. More might be said on this topic, but sufficient has been brought out here, it would seem, to show that there is a coincidence, even to very localized relations, between the average densities of comagmatic 318 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. regions in the United States and their gravity anomalies. Also, they appear to be too concordant to be the result of chance, so that we are justified in assuming that the two are causally related and that the theory of isostasy is thus justified. SUMMARY, After brief consideration of the interior of the earth, the general characters of igneous rocks are discussed, and the presence of water vapor and other gases in the magma, and its analogy with a salt solution, are pointed out. In the discussion of the mineral characters of rocks, stress is laid on the fact that the number of essential rock- forming minerals is very small. These are mostly silicates of Al, Fe, Mg, Ca, Na, and K. Any two or more of these minerals (with two or three exceptions) may occur together and in any proportions. The chemical characters of igneous rocks are summarized and the ranges and maxima of the various constituents are given. The average igneous rock is considered, and after some discussion of the sources of error involved in the calculation, a new average in terms of oxides (based on 5,159 analyses) is given. The average rock is shown to be approximately a granodiorite. The average composition of the earth’s crust in terms of elements is also given. Twelve elements (O, Si, Al, Fe, Ca, Na, K, Mg, Ti. H, P, and Mn) make up 99.61 per cent of the crust. The elements are referred to two main groups in the periodic table: (1) The petrogenic elements, characteristic of and most abun- dant in the igneous rocks, of low atomic weight, and occurring nor- mally as oxides, silicates, chlorides, and fluorides; (2) the metallo- genic elements, rare or absent in igneous rocks, but occurring as ores, of high atomic weight and forming in nature “ native” metals, sulphides, arsenides, bromides, etc., but not primarily oxides or silicates. The suggestion is made that beneath the silicate crust of petrogenic elements is a zone essentially of nickel-iron and beneath this a central core of the metallogenic elements. This vertical dis- tribution is in accord with Abbot’s views as to the distribution of the elements in the sun. In igneous rocks and minerals the elements show a correlation, in that certain of them are prone to occur with others, and a similar limited correlation is apparently true of the animal and vegetable kingdoms. The idea of “comagmatic regions”—that is, the distribution of igneous rocks in regions of chemically related magmas—is discussed. and some of these are briefly described. EARTH ’S CRUST—WASHINGTON. 319 The calculation of rock densities from their chemical composi- tion is discussed and the average chemical compositions and densities of the continental masses and oceanic floors are given. It is shown by these that the average densities of the continents, ocean floors, and various smaller regions of the earth stand in inverse relation to their elevations. The bearing of this relation of average density and elevation on the theory of isostasy is pointed out, and it is shown that the data presented are confirmative of the theory. Sime 4: Tay TD a 5 : 3 + 7 P it” j SSIS vy F re 2 x . 4 . rice Lasts Set & F al > it i ; 29> 7 ¥ o ™ SUEhB00 DTS Sees or -TRITISnEIIOS 5 odiensh Sloot te wontalrates Gat 135 a varteoel to vrosds add ao o inva! 4 +) (a te Ee ee : i] ie 9 gontevh sit Gin Ts Goaidsintion? S2HRisvs exig 7H} saokt . i to anormet isliinow esornsy ba i - = mi 5 Stes ale ~ eo ae pee Le eeiht ined Oey. & BEOLIRTSLS 119s er \e MAJOR CAUSES OF LAND AND SEA OSCIL- LATIONS.* By E. O. Urricy, United States Geological Survey. That the position of the strand line—hence the relation of land and sea levels—is and has ever been subject to change is a fact now established beyond all possible contradiction. The evidence shows that at times the shore line retreated, leaving such features as ele- vated sea plains and cliffs on the enlarged land areas; at other times the seas advanced on the land, drowning previous river val- leys, cutting new sea plains, and laying marine deposits much far- ther inland than before. These frequentiy recurring positive and negative movements of the strand line varied greatly in amount, but on the whole they were rhythmic in occurrence and volume. But neither the record of these movements nor the rhythm that runs through it is at all simple. Most of the criteria by which we de- termine that submergence has occurred in one case and emergence in another are relatively simple and easily applied. But when it comes to correlating the successive stages of emergence and _ sub- mergence in different localities, or when we seek to arrange the movements in proper sequence and to determine their relative dura- tion, the problems become involved and often exceedingly complex. The evidence presented, especially in the past few years, by Vaughan, Daly, and Barrell seems to prove that at least the marginal parts of the continents have been subjected repeatedly in recent geologic ages to positive and negative displacements of the strand line; also that the vertical element of these oscillations is not uni- form in amount at different places. Considering only the Pleisto- cene to Recent movements, their differential character at once sug- gests that these were in no case wholly due to either the alternate storing and unloading of water in the form of ice on the lands or, as Suess and Schuchert have it, to retreats occasioned by periodic deformation and deepening of oceanic basins and ensuing slow sub- 1 Presidential address delivered before the Geological Society of Washington, Dec. 10, 1919. Reprinted by permission from the Journal of the Washington Academy of Sciences, vol. 10, No. 3, Feb. 4, 1920. 42803 °—22 21 321 322 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. mergence by deposition of land detritus in the seas. Doubtless both of these processes contributed to the displacements of the strand line—clastic deposition continuously, and deglaciation more occa- sionally, in effecting submergence; accumulation of glacial ice and submarine deformation in effecting emergence. In all cases the work of these agents tended to produce an even rise or fall of the sea level. So far then as the coast lands are concerned the displacement of the strand line by these two causes would have been essentially eustatic. But we know that, commonly at least, the displacement of the strand line was not entirely eustatic but more or less differential even in short distances. Other causes, such as deformation by load- ing, variable gravitational attraction, etc., must have contributed to produce the complex result. Of these other factors, I am sure locally varying movements within the land masses themselves, in- cluding the more or less submerged shelf, are the most important. What the relative effects of the several factors in each particular case may have been constitutes a most difficult and varying problem. These proportions can not possibly have been the same in all cases. Besides only one of the causes of submergence—namely, the filling of the sea basins with deposit—could have been constantly in oper- ation though obviously most variable in the volume of result. Then, on the other hand, either sudden or gradual deepening of an ocean basin would hy itself suffice in effecting emergence. Up to a certain point I agree with the suggestions of Penck, Daly, and others concerning the competence of the Pleistocene ice sheets to effect considerable lowering of the sea level; and the evi- dence indicating warping of the land surface, because of the uneven distribution of the ice load, as first pointed out by Jamieson, seems to me reasonably compelling. I believe also that in deglaciation the land surface largely reestablished itself by elastic, or rather, isostatic rebound to preceding relief. Though accepting in modified form the idea of glacial control of particularly Pleistocene sea levels, it is not to be denied that the present well-known occurrence in Newfoundland and in re- mote outlying stations along the coast of New England and the Maritime Provinces of many plants characteristic of the coastal plain of New Jersey and the south tends, as expressed by Bar- rell,? “to ruie out the hypothesis that emergence was controlled only by the level of the ocean water as controlled in turn by gla- ciation.” The extraordinary distribution of plants referred to could not be brought about by natural processes to-day. Evidently the northern occurrence of this flora is to be viewed as remnants of a 2 Amer. Journ. Sci., 40, 17, 1915. ee Ae LAND AND SEA OSCILLATIONS—ULRICH. 323 preceding continuous distribution established when the climate of the northeastern coast was warmer and its coastal strip higher, wider, and much less broken by water gaps. ‘These required land con- _ ditions may be readily conceived as having obtained during, and as having resulted from, the ice loading of the glaciated regions to the west and northwest. As the latter sank under their growing load the continental shelf bulged its surface above sea level. But whether the plant migration could have been effected during the maximum extent of the Labrador Pleistocene ice sheet is so doubtful that Barrell* thought it necessary to assume delay in the settling back of the upwarped marginal zone after the removal of the ice sheet. As defined by Barrell, his hypothesis is “that the weight of the ice sheets caused crustal depression directly below the load, but moderate elevation in a wide zone beyond the load. Upon the removal of the ice it appears the first isostatic upwarping carried up higher this marginal upwarped zone with it. Being already an upswollen tract the broader regional movement carried it up to a level where it became unstable and a slow settling back occurred as an after effect, coincident with the last stages of upwarping over the centers of glacial load. The actual] evidence at hand does not decide between these hypotheses. The association with the close of gla- ciation appears to favor a genetic connection with deglaciation, but, on the other hand, it remains to be- demonstrated why the extra- marginal zone should rise together with the region directly glaciated, or that the cycle was restricted to such an extra-marginal zone.” That the eastern margin of the continent, south of Labrador, did rise to higher levels than the present during the retreat of at least the last Pleistocene ice sheet seems, with Barrell’s interpretation of Woodworth’s* data and conclusions regarding “Ancient Water Levels” of the Champlain and Hudson Valleys, highly probable. In- deed, supported as this evidence is by the facts concerning the dis- tribution of the coastal plain flora just alluded to, emergence of this marginal area at this time may justly be accepted as reasonably es- tablished. As will have been observed in the quotation, Barrell’s hesitancy in adopting this hypothesis arose mainly from the uncom- pleted demonstration of “why the extramarginal zone should rise together with the region directly glaciated.” Tn thinking this matter over the possible solution of the difficulty somewhat crudely illustrated in figure 1 has been reached. The diagram represents in generalized profile four Pleistocene stages of eastern North America, the profile running southeastwardly from Labrador to the edge of the continental shelf. The stages are repre- %Tdem, pp. 19-21. *N. Y. State Education Department, Bull, 84, 1905. 324 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. sented separately, showing relief of land surface in each and the extent of the ice sheet in the maximum and two partly deglaciated stages. The fourth represents the present condition. One of the new features is that as the ice retreated the normally positive strip bordering the present eastern shore responded at once to the release from directly applied weight pressure by rising. Emergence of this Piedmont and Coastal plain strip would be further insured by the necessity of maintaining isostatic balance with the outer strip of the continental shelf which had bulged to emergent status by subterra- nean flow from beneath the ice loaded land. In consequence, as the LABRADOR NEW ENGLAND COASTAL PLAIN AND CONTINENTAL SHELF 4EVER 4 SEA LEVEL Fic. 1.—Generalized profiles of eastern North America in Pleistocene stages, indicating isostatic vertical movements of surface of lithosphere in process of deglaciation: 1, Dur- ing maximum extent of ice sheet, when the outer part of continental shelf was emerged ; 2, When the ice load had retreated from the present coastal strip; 3, A later stage when the ice sheet had been reduced to the area of Labrador; 4, Present relief of land, with submergence of continental shelf. Approximately similar conditions may be supposed to have obtained in the growing stages of the ice sheet, ice sheet retreated the emerged outer part of the continental shelf began to sink, whereas the strip along the landward side of the present shore rose. Among the physiographic changes that may be supposed to have occurred at the time of this southwardly decreas- ing elevation of the coast lands north of Baltimore is the cutting of the now buried deep channel of the lower Hudson; also the sharp southward deflection of the Delaware and Susquehanna Rivers. Dur- ing the preceding maximum extent of the ice sheet Maryland is sup- posed to have stood higher than at present and the lower stretches of these rivers either flowed northeastwardly or they emptied more directly and much sooner into the sea, which then probably covered LAND AND SEA OSCILLATIONS—ULRICH. 325 the New Jersey part of the coastal plain and extended widely into the eastern valleys of the adjacent Appalachian region. As the ice sheet retreated Maryland settled back while the coast lands to the north rose. The resulting emergence and the reversal of the tilt of the land surface must have rpotaeed corresponding changes in the direction of flow of affected rivers. Obviously results like these re- quired practically immediate isostatic response to both the accumu- lation and the removal of the burden of ice and not as Barrell thought, “a deferred intermittent, and possibly oscillatory, read- justment.” (Op. cit. p. 21.) On further retreat of the ice front the upward movement of the latter was arrested and finally reversed, so that it shared in the general subsidence of the marginal area when the complete withdrawal of the ice sheet permitted isostatic rebound of the unloaded interior highlands to their preceding and present normal land altitudes. In consequence of the bulging of the sea bottom adjacent to shore lines that in the maximum spread of the ice sheets had sunk beneath the load of ice, the capacity of the ocean basin must have been cor- respondingly lessened. This in turn would have tended to retard and finally reverse the downward direction of the change in sea level previously prevailing on account of subtraction of ocean water for the making of the ice sheet. Thai is, it would have caused actual raising of sea level except in those parts of the shore line that were covered by the ice sheet and therefore directly affected by its weight. The upward movement of the sea level thereby occasioned would have been worldwide and eustatic. But the displacements of the Pleistocene strand line along the . Atlantic coast that were in any wise connected with glaciation must, because of varying conditions arising from the fact that the ice sheets did not reach the shore line south of New Jersey, have varied greatly in amount and direction at different places. It was only in the early stages of glaciation, before peripheral elevation of the surface of the lithosphere with respect to areas bearing ice loads had progressed to the stage wherein it caused materia] lessening of capacity of ocean basins, that the sinking of sea level could have been eustatiec. On the reversal of this sea-level movement, when the Pleistocene ice sheet stretched to the shore and when as stated above, the consequent bulging of adjacent parts of the continental shelf reduced the capac- ity of the ocean basin, the change in sea level as manifested in the advance and retreat of the Atlantic shore north of, say Cape Hat- teras, was far from eustatic. During this maximum extent of the Labrador ice sheet, the ice-covered near-shore lands about the Gulf of St. Lawrence must have sustained extensive submergence. South- wardly from northern Maine to New Jersey the amount of this sub- mergence decreased perhaps to its minimum. On the other hand. in 326 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. Maryland, which I take to have lain at that time within the belt of peripheral isostatic elevation, the land was pushed up with resultant apparent or relative sinking of sea level. Farther south, beyond the belt of peripheral bulging, the Atlantic shore probably shared in the eustatic rise of sea level that prevailed generally. because of the tem- porarily decreased capacity of ocean basins except in the areas affected immediately and differentially by the ice sheets. Correlation of Pleistocene sea beaches in Maryland and Maine therefore suggests and perhaps requires comparison of the low beaches in Maryland with high beaches in New England. Because of this dissimilarity in manifestation, it seems to me that it is only in the warm temperate and tropical zones lying well be- yond the areas in which isostatic balance would be materially dis- turbed by known ice loading of lands, that the sequence and amount of the several glacially controlled Pleistocene changes of sea level are recorded in their proper relations to the actual fluctuations of the volume of sea water and to the capacity variations of the basins holding it. But even in tropical areas the complete sequence of the oscillations and the immediate cause of each can not be worked out without taking strict account of what was happening at the same times in higher latitudes. In thinking of the progressive and regressive sequences of move- ments it is well to remember that ice loading and sediment (rock) loading of epicontinental areas are comparable in their deforma- tional effects on the lithosphere only in one respect—that is, in both cases the loaded area sinks. They differ, primarily, in that the ice cap originates on, and spreads outwardly from, normaily positive areas, whereas the rock sediments are laid only in areas of relatively negative tendencies. Subsidence because of ice loading, therefore, is an abnormal process in that it is carried on under unusual condi- tions, so that normal gravitational tendencies are reversed; in the other case not only the process but the results also are perfectly in accord with the normal gravitational tendencies of the affected areas. Next, they differ in that the ice sheets presently melt away, whereas the water-laid rock deposits commonly remain as a permanent asset of the area covered by them. SS SS ee ee a ei ee LAND AND SEA OSCILLATIONS—ULRICH. 327 Paleozoic stratigraphy are cited in my evision in support of this belief, and Barrell, in 1915, expressed himself as favoring the view. Now, if we accept this conclusion it certainly does not help the hypothesis of measurable sea-level fall by storing of oceanic waters in continental ice sheets. Obviously, the subtraction of water from the seas to make the ice sheets must have been a slow and on the whole gradual process; and the time consumed in the growth of the ice sheets probably was not materially shorter or longer than that required in their melting. From these considerations it is clearly evident how exceedingly diffi- cult is the proper determination of the part actually played by glacia- tion and ensuing deglaciation in the emergence and submergence of the continental borders. The fall and rise of sea level directly resulting from the storing of oceanic water to make a great ice sheet that later is returned to the sea is so intricately connected and interwoven with genetically similar but at times oppositely directed general and local deformations of land areas and also of sea-bottom areas adja- cent to the strand line, that the reliable valuation of the two or more factors seems as yet practically hopeless. Moreover, it appears to me that only the early and the late stages of a period of glacial con- trol could have made and left anything approaching world-wide and vertically equal records of consequent displacements of the strand line. The early stages would be those in which the lateral growth of the ice sheet had not yet reached the zone in which the weight of the ice would have caused extramarginal bulging and apparent lowering of sea level far in excess of the fall actually occasioned by transferal of water from the sea to the land. Simi- larly the later stages would be those following the retreat of the ice sheet to the same relatively innocuous limits. It follows then that only the eustatic smaller shiftings of the Pleistocene sea levels may be definitely ascribed to storing and sub- sequent release of frozen water on the land. And for these even it is mainly their occurrence in a known ice age that induces one to admit their probable glacial origin. However, the larger and in most instances also much more local Pleistocene oscillations of the strand line, even granting that their causation is intimately connected with ice loading and unloading of land areas, belong to another category. Strictly speaking, these larger displacements have resulted from truly diastrophic causes and processes that are concerned with the ‘maintenance of the isostatic equilibrium of the lithosphere. Under the circumstances, then, I must agree with Barrell in con- cluding that the amount of water taken from the seas for the forma- tion of the ice sheets was not a direct “major factor in the control of Pleistocene sea levels.” Movements, acting within, beneath, and 328 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920, upon the lithosphere thus appear to have been the more effective factors. That the marginal areas of the continents were at times elevated and folded is, of course, accepted by all—even by Suess and his fol- lowers, who speak of the continents as having the character of “horsts” and of the ocean basins as being permanently “sunken areas.” Suess, however, believed that the median areas of the conti- nents are essentially stable, a view adopted by Schuchert, who holds “that the continent (North America) is a horst, that the great medial region remained unmoved, while the margins were often folded and elevated. The seas periodically flowed over this medial land—in fact, were elevated over it—owing to the detrital materials unloaded into the oceanic areas, thus filling them and causing them to spill over on to the lands.” I can not subscribe to this opinion. On the contrary, though ac- cepting the idea of permanent oceans and continents, it seems to me that the crust of the lithosphere was subject to periodic movement away from the poles; that the surface of the lands was exceedingly unstable in the median areas as well as along the borders of the continents. Schuchert’s paleogeographic maps, indeed, offer con- vincing proof of such instability; and the more detailed maps made since his appeared further substantiate my claim. In reaching these conclusions I am mainly influenced by a life- time study of Paleozoic formations and their faunas. The criteria and principles used in the course of these stratigraphic investiga- tions are defined and discussed in my Levision of the Paleozoic Sys- tems, published in 1911. In this work more than 100 previously un- described instances of differential vertical movements of lands and consequent shifting of seas are discussed in varying detail. Since 1910 much additional information has been gathered concerning such oscillations in North America. On this occasion I shall mention briefly some of the more con- vincing of the published cases and in greater detail a few of the more recently determined instances—enough of both to show that from the beginning of Cambrian time the surface of the continents was exceedingly unstable and subject to frequent oscillation, and that the epicontinental seas were correspondingly inconstant, shal- low, relatively small, and frequently withdrawn in part or entirely. Even in the same geological provinces the outlines of the new sea may agree essentially and often very closely, in parts, with the next preceding or some earlier sea, but in other parts the new shore line departs radically from the older. These movements occurred in Paleozoic ages which, unlike the Pleistocene, have left no record of great ice accumulations. Doubt- less even in the Paleozoic there were times of relative frigidity, LAND AND SEA OSCILLATIONS—ULRICH. 829 when some of the higher parts of the marginal lands were ice- covered, in some instances attaining locally to glacial conditions. Here and there regular tillites are indicated, notably as recently brought out by Dr. Edwin Kirk, in the Silurian deposits along the coast of Alaska. Occasionally, too, transportation of bulky erratics by heavy shore ice is suggested, as, for instance, by the late Ordo- vician Rysedorph hill conglomerate near Albany, New York, and the great masses of unworn limestone of Ordovician and Silurian , ages found in the early Pennsylvanian Caney shale of eastern Okla- homa. But the Paleozoic history of North America so far as known affords no suggestion of ice ages comparable to the Pleistocene period in the amount of water abstracted for the formation of the ice sheets. Moreover, by far the majority of the displacements of the strand line in the continental seas occurred at times and places that give no indication whatever of particularly cool climates. On the contrary, the entombed faunas in the overlapping and interfingering marine formations could hardly have lived in the shallow seas if the climate of the adjacent lands had not been mild. With the data in hand I feel warranted in asserting that the level of the Paleozoic continental seas was seldom appreciably affected and certainly never controlled by glaciation. Besides, the appar- ently irregular, though doubtless rhythmic, shiftings of the strand line almost without exception indicate local differential movement in the continental surface. And these movements must have been connected with other more general movements, requiring at times partial or complete withdrawal of the waters from the land depres- sions, at other times permitting readvance in the same or some other newly depressed land basin. The varying distribution of marine deposits of successive ages naturally suggests differential upward and downward movement of the lands as the immediate cause. If the submergences had been occasioned solely by rise of the waters, the successive submergences would have been always similar in geographic pattern and different only in lateral extent. In fact, a general similarity or repetition of old patterns is recognizable, but there is also exceeding diversity of expression, and often the difference is greatest when directly succeed- ing stages are compared. Often, again, when one stage appears to have been very different from the next, the following third or fourth may be very much like the first. Only oscillatory movements or warping of the land surfaces could produce such results. The area affected by such movements may be very large, as, for instance, dur- ing the Middle Ordovician and Middle Silurian, when nearly half of the continent of North America was involved. During these periods the Gulf waters seem at certain times to have been completely with- drawn from the southern part of the continent, the middle and 330 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. northern parts at such times being tilted so that the boreal sea ex- tended southward beyond Chicago and occasionally as far as northern Tennessee. Strictly, these widely operating movements hardly fall under the category of epeirogenic movements. On the other hand, they are not truly orogenic, if that term is to be confined to movements originating in shrinkage of the centrosphere. Apparently they indi- cate a combination of causes, perhaps beginning or ending with the play of orogenic factors that built mountains in the submarginal areas, whereas the warping and deformation of the more stable interior areas was mainly occasioned by the necessity of isostatic readjustments to stresses incident to the greater deformations of the orogenic movements. Then there were many relatively local changes in the strand line of continental seas that may be explained only by assuming corre- spondingly local differential, vertical movements of the lithosphere. I do not refer to movements connected with volcanism. On the con- trary, the best examples of the kind in mind are found in areas but rarely or not at all directly affected by volcanism. These differential movements indicate actual elevation of one area while another near by was sinking. Moreover, in the next recorded age the directions of ensuing movements at the two places often were reversed. The phenomenon might be likened to a gently convex platform supported in the middle and tilted alternately to the east and west and at other times to the north and south. The condition is recognized by the alternate presence and absence of sediments of particular ages on opposite sides of the tilting platform. (See fig. 2.) Comparative studies of the Paleozoic deposits in the Appalachian Valley region, from eastern Pennsylvania on the north and central Alabama on the south, have brought out over a hundred clearly de- fined examples of such oscillations. They are manifested by the restricted distribution or local deposition of many overlapping forma- tions, having maximum thicknesses of from 200 to over 2,000 feet. In many cases these formations are wholly or mainly confined to one or more narrow, troughlike, longitudinal divisions of the Appalachian geosyncline and commonly to one or another of three divisions of the geosyncline that are more or less effectively separated from each other by low transverse axes. The most northerly of these broad axes passes across the valley between Carlisle and Lebanon, Pennsyl- vania. It is known as the Harrisburg axis. The next, to the south, intersects the valley of Virginia between Staunton and Harrison- burg. The third, or Wytheville axis, passes across southwestern Virginia, which is to-day the highest and narrowest part of the great valley. The fourth axis crosses in a more northerly direction than LAND AND SEA OSCILLATIONS—ULRICH. 331 the others-through the belt lying between Rome, Georgia, and Gads- den, Alabama. | These transverse axes do not cross the longitudinal troughs of the geosyncline in continuous direct lines. On the contrary, their course zigzags within the varying limits of a broad band, so that the north- ern head of a bay in one trough may extend 50 miles or more beyond the latitude of the southern head of another younger or older bay in an adjacent trough. The band is wide enough and was always low enough so that regional tilting occasionally permitted overlap of edges of formations transgressing from opposite directions. Often Fic. 2.—Diagram illustrating tilting of interior areas of uplift (for example, the Cincin- nati dome), and the consequent variations in amounts of advance and retreat of the sea on their opposite sides. Arrows indicate direction of horizontal stresses. The letters A, A’, A”, on the one side, and B, B’, and B”, on the other, mark the same points on the flanks of the dome in all of the three stages. In 1 the sea laps equally on both sides; in 2 the elevation of the dome is accentuated and its summit has migrated to the left, while the sea has advanced much more on the right side than on the left; in 3 the summit has migrated in the opposite direction so that the deposits of the preceding stage on the right fianks are largely emerged, whereas on the submerged left flank the new sea widely overlaps the deposits of the two preceding stages (1’ and 2’). the axis formed an efficient barrier in one trough and was much less effective in the one next to the west or east. More rarely, a bay, ter- minated at the north by a transverse axis, connected laterally with waters in an adjoining trough in which the submergence was not stopped by the axis. Finally, at other times the axis offered no serious obstacle to the passage of the marine invasion. Of course, the indi- vidual troughs were submerged over and over again, but in none do we find representatives of all of the formations known to have been deposited in the Appalachian Valley. Varying geographic expressions like these could have been made possible only by differential vertical movements in the concerned 332 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. parts of the lithosphere, and these Appalachian oscillations in sea level were by no means small affairs. Most of them are measured by hundreds of feet and some by thousands. Excellent and very interesting oscillations occurred about those more inland and very ancient positive areas known as the Cincinnati and Nashville domes, the Ozark and Adirondack uplifts, and the Wisconsin peninsula. Of the many formations that are found on their flanks and which failed to pass over them much the greater number are confined to one or the other side. The sequence of formations on either side therefore differs greatly from that on the opposite side. Much space is devoted in my Revision of the Paleozoic Systems to a description of the inequalities in areal distribution of the forma- tions that were laid down on the flanks of these epicontinental domes. With a few corrections and modifications, in every case tending to.emphasize rather than to weaken the argument based on the observed phenomena, the published statements concerning them in that work have been further substantiated by more recent investi- gations. Instead of overstating the number of oscillations in that paper we can now prove many more instances than were known or even suspected by me in 1910, In New York State alone the joint investigations carried on in the Ordovician shales and limestones on the south and west sides of the Adirondack mass by Doctor Ruedemann and myself, and on the Medina and Clinton formations with Mr. Hartnagle, have increased the established cases of sea shifting implying more or less decided differentia] vertical movements in the adjacent land masses to more than twice the number contemplated when I wrote the Revision. Similarly the work of Mr. Charles Butts and myself on the Mississippian formations in Illinois, Kentucky, Tennessee, and Ala- bama has developed oscillations of like character that were scarcely suspected six years ago. Very notable additions to our knowledge of Cambrian and Ozark- ian oscillations also have been made in the course of my work on the Paleozoic formations in Wisconsin. Before closing permit me to give some details concerning at least one of many similar new discoveries in this and adjoining States. Only a few years ago the stratigraphy of the Cambrian deposits in the upper Mississippi Valley was practically unknown or at best only very imperfectly understood. Because of certain misappre- hensions, now clearly understood, the correlations of the several sections by the State geologists of Wisconsin, Minnesota, and Towa were not only inadequate but quite in error. So long as the observed variations in character of deposits and their fossil faunas were supposed to indicate nothing more than LAND AND SEA OSCILLATIONS—ULRICH. 3145] merely local variations in contemporary seas and life it was almost impossible to work out the true relations of the beds in the largely drift-covered, and hence discontinuous exposures of the Cambrian rocks. A new viewpoint was required; also closer investigation of bedding planes, greater accuracy in noting the vertical and geo- graphic ranges of particular species and faunal associations and of particular beds. In short, it was necessary to employ more modern criteria, principles, and methods than had been used before. When the work of revising the Paleozoic stratigraphy of Wiscon- sin was begun in 1914 the task seemed relatively simple in view of the success that had attended our investigations in the supposedly more difficult fields in the Appalachian region, about the Cincin- nati and Nashville domes, and the Ozark and Adirondack uplifts. Indeed, the results of the first season’s work in Wisconsin were so satisfactory to Doctor Walcott that he decided to publish my revised section in his work on the Dikelocephalid trilobites.® As therein given the Upper Cambrian series in the Mississippi Valley is divisible into six lithologically and faunally distinct formations, named from below upward: The Mount Simon sandstone, which rests on pre- Cambrian crystallines, followed in turn by the Eau Claire shale, the Dresbach sandstone, the Franconia (glauconite bearing) sand- stone, the St. Lawrence formation of limestone, shale and sandstone, and the Jordan sandstone. Above these came the Lower Ozarkian Mendota limestone and the Madison sandstone, the last of which is overlain by the Oneota dolomite of the “Lower Magnesian” series, Aside from the determination of the lithologic and faunal sequence of the Cambrian in the western half of the State, the most important improvement brought about by the first season’s work was the proof that the Mendota limestone and Madison sandstone are really post-Cambrian formations and not, as had been supposed previously, the eastern representatives of, respectively, the St. Law- rence limestone and the Jordan sandstone of Minnesota. In fact, it was then believed and has since been definitely proved that whereas the St. Lawrence extends uninterruptedly from Minnesota and Iowa across the southern half of Wisconsin and under cover of later formations into northern Illinois, the Mendota limestone is entirely absent to the west of a narrow trough running southeastwardly from the southern slope of the pre-Cambrian Baraboo quartzite range. In the following field season of 1915 doubt arose as to the eastward extension of the Franconia formation to and beyond Madison. At this place there is a more or less decidedly calcareous sandstone for- mation, approximately 100 feet in thickness, which lies between un- 5 Dikelocephalus and other genera of the Dikelocephalinae. Smithsonian Misc. Coll. 57, 1914. 334 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. questionable Dresbach sandstone and no less certainly established St. Lawrence limestone and shale. The intervening formation therefore seems to occupy the same stratigraphic position as the Franconia. But its lithological characteristics, except that it also contains con- siderable, though more disseminated glauconite, are quite different from those of the Franconia; and whereas good fossil remains of characteristic types are exceedingly abundant in the Franconia they appear to be much fewer and, so far as could be determined from the handful of fragments then procured, of different species. In casting about for a means of determining the problem I thought of an old anticline that extends southwestward from the Baraboo range across southern Wisconsin into Illinois. This axis had pre- viously been found to have had an important effect on the distribu- tion of the Ordovician formations and it seemed worth while to see whether it had not been in existence, and functioning as a barrier, SOUTH OF BARABOO PRE-CAMBRIAN RANGES west eAsT Mississipp River Green Vit Madison and — Devils Lake SHAKOPEE DOLOMITE SHAKOPEE DOLOMITE ONEOTA DOLOMITE WABISoOn San oSISE SS “END al oY: 7 JORDAN SANDSTONE enn ~ : a “ST LAWRENCE” ee’ CAMBRIAN ? Fie. 3.—Section across southern Wisconsin, showing sequence of Upper Cambrian (St. Croixian, and Ozarkian formations, the apparently similar stratigraphic positions of the Franconia and Mazomanie formations, and the absence of both on the summit of the pre-Cambrian anticline. already in the Cambrian. Accordingly, a part of the season of 1916 was devoted to following the nearly continuous exposures of Cam- brian rocks in the bluffs and valley walls along the Wisconsin River. Beginning at Boscobel and going upstream, the Franconia, in typical development, was found to hold its own for a distance of about 20 miles, when it began slowly to lose thickness by overlap. The succeeding 15 miles, which brought us to the town of Lone Rock, sufficed to pinch the formation out entirely. Beyond Lone Rock, for a distance of about 10 miles, in which we passed through the town of Spring Green, the Franconia is absent, the top of the underlying Dresbach sandstone has risen considerably above the river level and is immediately followed by characteristically fossiliferous shales and limestone of St. Lawrence age. (See fig. 3.) Just east of Spring Green the closed contact between the Dresbach and St. Lawrence opens again to receive the wedge of magnesian sandstone whose age was the quest of the undertaking. Where first LAND AND SEA OSCILLATIONS—ULRICH. 835 exposed in the bluffs east of Spring Green the Mazomanie sandstone, as the new formation is called, is about 10 feet thick. Four miles east of the town it has thickened to 80 feet, and at Fairy Bluff it reaches 100 feet. Wherever it rises to considerable heights above the valley bottoms in Dane, Sauk, and Columbia counties it forms cliffs, which is not at all true of the typical Franconia. But, so far as positive evidence regarding the age relations of the Franconia and the Mazomanie is concerned, these investigations of the bluffs along the Wisconsin River left the question as unsolved as before. Nor did we come any nearer to its satisfactory solution in the course of the following season’s work when a series of sections was made on the south side and around the eastern end of the Baraboo Range. But just before the close of the field studies in 1918 some very promising but under the circumstances inconclusive NORTH OF BARABOO RANGE Mississippi River Pilot Knob Bertin Fie. 4.—Section across central Wisconsin, showing greater eastward extent of the Fran- conia in this part of the State and intercalation of the Mazomanie between the top of the Franconia and the base of the St. Lawrence. observations were made in sectioning the outliers and bluffs which dot the sandy plain of central Wisconsin. Namely, at one of these bluffs I found a perfectly characteristic Mazomanie cliff and beneath it a 2-foot exposure of reddish sandstone that seemed to me to be of Franconia age. However, the evidence at this place was not satisfactory to Dr. W. O. Hotchkiss, State Geologist, and Mr. F. Thwaites, who accom- panied me on this as on most of the other trips through the State. Their doubts arose mainly from the fact that my interpretation re- quired the assumption of a fault hitherto unsuspected between this bluff and Pilot Knob, which lies less than a mile to the northwest. And so it was left to the work of the past summer to clear away all doubt, if possible. And it was cleared away. Other outliers in this vicinity were visited until finally we found two that were capped by Mazomanie and St. Lawrence and beneath the Mazomanie showed 336 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. from 50 to 100 feet of profusely fossiliferous Franconia. Incident- ally the presence of the fault just mentioned was unquestionably es- tablished. As an interesting and welcome confirmation of the earlier conviction that the Franconia is older than the Mazomanie—wel- come despite the fact that it came to light after the case had been proved by actual superposition—I may add that two entirely new faunas, one from near the top, the other just above the base of the formation, were discovered in the Mazomanie. The upper of the two occurs rather widely distributed but in a sandstone so friable that it can not be picked up without crumbling in one’s hand. De- spite this difficulty a considerable collection was made and safely transported to Washington by soaking the sand with shellac. T have described the solution of this problem in greater detail than may seem necessary, first because of its intrinsic value and interest as a new instance of oppositely overlapping formations, second be- cause of its bearing on the question of differential surface move- ments, and third as an illustration of the thoroughness of modern stratigraphic investigations. The case shows differential movement, first in the fact that the Franconia is confined to the western half of the State, whereas the preceding Dresbach was laid down on the east side and over the south side as well as the west. Next, the very different distribution of the Mazomanie shows reversal of the tilt from the west toward the east. Further—through the fact that the two formations are sep- arated to the south of the Baraboo Range by a broad strip, in which neither is present, whereas to the north of the pre-Cambrian range both formations were laid down so that the younger overlaps the older for a distance of at least 50 miles—it is proved that the move- ment was not simply an east-west reversal of tilt but that it was accompanied by additional local subsidence on the north where a de- pression was formed that subsequently lodged a considerable embay- ment of the Mazomanie sea. But this does not exhaust the known record of diastrophic move- ments of this time in Wisconsin. Uplifts of the relatively evenly distributed floor of Dresbach sandstone are indicated in many places; and depressions occurred in other localities so that the Franconia lapped over in such places onto the pre-Cambrian rocks. This occurs at Taylors Falls, and possibly at Berlin,* towns located on opposite sides of the area covered by the formation. At Osceola, on the other hand, there is a narrow ridge on the surface of the Dresbach that completely cuts out the Franconia, though the formation is well de- veloped both to the north and south of Osceola. Finally, we recog- 8 Larger collections and a more thorough study of the fossils found in the Cambrian sandstone that lies on the uneven pre-Cambrian floor at Berlin, Wisconsin, tend to the conclusion that this bed is of Mazomanie or possibly even of St. Lawrence age, hence younger than the Franconia.—H. O. Ulrich, Mar. 18, 1921. LAND AND SEA OSCILLATIONS—ULRICH. 837 nize two longer upwarps of the Dresbach floor that extend in a south- westerly direction from the central pre-Cambrian land mass which formed the backbone of the Wisconsin peninsula. These buried ridges divided the Franconia sea into basins sufficiently distinct to show well-marked differences in their respective depositional sequen- ces and faunas. But why pile up the evidence, the sameness of which must weary you. Suffice it to say that the phenomena indicating differential ver- tical displacements of the strand line are everywhere about us and as abundant and well displayed in the areas of Paleozoic rocks as in those of more recent ages. One need but to compare a series of paleogeographic maps which, even despite their admittedly general- ized and synthetic nature, yet show—unmistakably and clearly— variations in outlines of successive continental seas that would have been impossible if the land surfaces periodically invaded by them had not been subject to frequent oscillation and warping. Physiographers, apparently, have paid little attention to these paleogeographic maps and the discussions of stratigraphic corre- lations that usually accompany them. Perhaps the reason for this oversight les in the fact that most of them have been made by pale- ontologists—a kind of geologist who should be seen but not heard on physiographic and diastrophic questions. But, after all, does not the stratigraphical paleontologist deal with a wider range of geological data and criteria than any other specialist in the science? Of them all, I regard the stratigraphical paleontologist the best equipped to bring out the dominant facts in questions of the kind before us. He has the same opportunities and desires to observe and note the physical factors of the problem, and in addition an appreciation of organic criteria that may not only be applied directly in the field but the tangible evidence—in the form of specimens usually small enough to be collected—may be carried to the laboratory and there be studied at leisure and as often as desired. I have found this of very great “ advantage. For such reasons I would be disposed to prejudice in favor of earth students like Vaughan or Schuchert in cases of controversy with others who can not personally take into account and weigh the or- ganic as well as the physical aspects of a problem. However, in the present instance I have gathered so much competent evidence of my own that I feel warranted in reaching the conviction that the major factors in the control and migration of the strand line lie and have always lain in deformative movements within the lithosphere. These movements, whether large or small and whether due to shrinkage of the centrosphere, to local changes in crustal density, to unequal load- ing by rock or ice, or to erosion and further lightening of positive areas, are all primarily concerned with the maintenance of isostasy. 42803°—22——22 of] THE BRYOZQA, OR MOSS ANIMALS. By R. 8. BASsLER, United States National Museum. [With 4 plates. ] CONTENTS. Page. Page ERRNO CDT oo er 839 | Types of Bryozoa—Continued. General characters... —.2 3.01 Ls 340 Superorder Gymnolaemata_______. 353 RRR CALIONI Ay

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Labor, Secretary of (member of the Institution) -_.___________+______ 11 Bey HALOS CHIC yea Hy TCT Se kL OLE alec pn ea a 12, 64 Lameere, Auguste (The origin of insect societies)_____________________ 511 Land and sea oscillations, Major causes of (Ulrich)___-______-_____.__ 321 Bia PONG 55 haleied eke ee eae ag ple a Seas re EN 8 ee gaa 45 angley,cs.)b.. toird secretary of the Institutions] ss ie eee 36 nH PESTSNUET ST ean 8 8 (ge | ce er a RNY ee ain te eye Ie aC See ie Se ho. 85 Mea rave A ey eee at ee a a 2 ea em ek 2 a 12, 70 CHT V5 ON LR RE tee OEE SIGS BSONORTS RSIS = SEAN INN Ep DOs ES Snap eA Hy! 26 for sbhe pV) MCS kes ei ca tees ae Si 2 pg ie ey ts eRe 26 Length of day and night, Hffect of the relative, on flowering and fruit- ins? of plants; (Garnersands Allard) .3 225 oe ee eee 569 AAO INET be TON Ory 4 © a a a Nd SL ea ee 2A 2d Mey OW; JH) preset eye W e S e 12. Svea iP Aye OT AG OST CSS es Nae eT a 29, 112. 18, AS LG Smithsonian Geposit ine 7.5 e seo ee NSE WEEE oc igs a al br Libraries of the Smithsonian Institution and branches______ 1S) 29) cols poeple IC COSSTORS so best Speen Shee Sh ht epee eS De ig ge 116 HETONAULICAT: GOVECTIO NS 2 2 2a 2 a ee pe Ro 114 AStrOphysical, Observatory, Lilet ye ecole ages epee eta 29, 115 IDeyPeysterscoulection= 2 === 2 e DU Ae ON el ibe SNe See geen Ree eee 29, 114. SMIPLOV EOS eit TA YI gy Rare ah 114 Hthnology,; Bureau of American, library 20229) 82, 70,115 TAY Gb ESX 250 00 AT} a2 ig ee em ices Bg agOe maT Se ae NE iy anh DD eS aN Re oe 55, 114 National: Zoological esamke. ib retry see a ee et 116 FEACIN Pe LOOM SMALE HS OTA 71 POUT ee eee ee 114 he 2 YO) ty PEL oR MUL NE oh I CS RMD ERS AE PN BSE WA a Sp ALC a LGN o Edie nha au eS A 112 STATUE ESOL TY LT Sagan UT Tea Wy oo a ee 112 STEMS Ora TI OMe. UTE en Te yee ate we ee er 2 WATE O Lisa Li Ce iy ee ALO oe ene 48 METNGOTN ERO tact, So ee Oe ee ae ne ey a Se a 59 Drath fe ees pee eRe TPE TTI es SLT BA aaa en CAEN a 26 Lodge, Senator Henry Cabot (Regent) __---______________ D4 2 te. aD QO coTs) a) gant 24 aro eat 4 KO gh yy k= Wace iteli G oehpam riche etl ae can enh yah naan il lw pa es ae 5 50 | =¢ 4 fb Ct =) Fs Sa a ar ear pw Dg ne AT Lao su nears yA 1 el 2 50 collectionTo& Chemical’ ty Pese aaa ee es ee ee 51 #1161 1 0 | a aR PERE Dire ra elon MNRAS eoN ERS Pasar n uN Yl cA Be 51 OWOSSO > 8 et Se SE EN Ie st cca ee DL OE 44 —— INDEX. 699 M. Page. FT SAI Gg OPS eR COREE TE ee ee ae Ce ae 48, 68, 72 OL Tea tg DY eee Wipe I ee ee ee ne eee Es OL 45, 86 WOME POT OUI OPT UIC TI CSEY 00a I 49 Mars, Venus, and other worlds, The habitability of (Abbot) -__________ 165 Marshall, Themas R., Vice President of the United States (Regent and mMmemper Of the-InstitwioOn) ——=-—-<=—2 2 11, dsyita 127, Marvin, Charles F., Chief, Weather Bureau__-____-___--___-__-______ 104, 105 Manviand:Geolofical Survey 2 eta e e E 46 Mass spectra of the chemical elements, Doctor Aston’s experiments on (introductions byCwG. Abbot) <2. = -2 2 22. 2 LL 223 BUNGE cena SpA V or i ae ha er oe ee ee ADA a aT, 114 Cihesbotanical: cardens)-of- Jamaica) ==. = ne 523 McAtee, W. L. (Local suppression of agricultural pests by birds) —~-_____ 411 MeGlellan. Maj. Gen. -George. Ba=2+2--+-25---_ 2 Losey be noe 30 INCOMING) PsCy wil = 2S OE) Ie IN) aly) Sein lange fae 55 McCormick, Senator Medill (Regent) —--—--~--.---.2 52) 2s 11, 4 ee Melndoo.e Ni. (ihe. senses of insects) 22. 461 apa lee rien hisira a atte eben St se Sy sae? pee eee 40 Mere ec mren: wlleter SON ae ee 42 Mechanical technology, collections in the division of, National Museum __ 48 Medicine, collections in the division of, National Museum___________--_- 47 Meetings, congresses, and lectures, National Museum____---__-_--______ 31, 53 PRUNES PT Thee Cer TUB em nat A a eee ate Be 136 Mrenmibers: Of the -nstitubtion - 2s ao a a te ee eg wa juve) oo Feyod ef2 110 leat 0) Pag, ©) een &) Pea ee ee Se Dee eee es ee ere aE EME NC ape MUmeaiaee a 141° 2-1 104 Renee: “Hmperor = 2. “= 2245-2 esn5 ea sasennskaesee tea Ea 90 Meredith, Edwin Thomas, Secretary of Agriculture (member of the ST ACUELON) <2 2 a ee ee ee 11 Merrill Dn. Georee Piss. 2-22 es eee bene een Ee Se 12,29 Menealts Willard (ys ==— 2-22 ot eet en Oe eis _ A 136 Meteorological paradoxes, A bundle of (Humphreys) ------__---_-__--_- 183 Mexicans, ancient and modern, Notes on the dances, music, and songs PLE CGN Tg YEE A i I eR eee NOU Serer le, ee ee Pe eee 657 Te CTERLD CST ay SA Dye TE aN ee See eee ee 12, 65 Vallee Tren Gaia y Sa ee ee ee ee eee Soe ee ae 12 Mineral technology, collections in the division of, National Museum_____ 48 Te Uy SEE 0 | MA aT i i ae ee 40 ENT TN Ei CIS Ne Sa = nee ena ee ee 12, 26 May Emeniuin a Milne see a ee ee ea ee ee Sere ee ee ee 46 Bc 5 SEPSIS ES SS eel a LN 0 i is SS ASD eat I 12, 61 ews ED EE tA A ee oe ie rc re I Ae ee 42 Re aR Pearly re DPN ANT en re a ee ie re ee 20 UD TM SEER ae ees renee aed 5 ly SE Bf ee BE vel DOTA S VET Sy eek A a tas A Ee a he 70 “7 Spam bos MEP Pe Stille Seah) ia) Rai TR ee EM SS AL Sk BS 136 PEELE TH Civy er eer oe Seen: eh erences oe yee ieee as: eee ee ee 44 © 2 RS J EE SIS RD act oy ee nee te mean ere Pe 43, 68, 69 National Academy of Sciences— COPAG SID SPUD CaN eX) 2 Y pe a DR SS He ROR OR be: 53 PTS TCO Oa ae UG Se Eee 139 700 INDEX. Pago. National Art: Commissionec 2 225 2). 2 es ee a ee ee 188 NationaltGallery of “Art=———45- 12, 16, 29, 80, 36, 49, 50, 129, 130, 137 itabtondl. esd: C0. s ee os ed ot a a ie era INSET eae TIME Vy Se ann a ee ea a i ee 12,.13,,18,,28,,29 ACCESSIONS === = steph AA See ob Uh shee ek erty AN ee a ep eg he Be a 30, 38 COMSGELOM Spa Sars A gt er We ees Le ar a ne a el 38 IS Ac Qtek hi eek by ec cintee pee beer pales SER ne pe eee eee RS iN wnteremar are Vee Pe 29, 31, 56,114, 115 meetings, congresses; and lecturegec.-42 fe ey 2 ee 31, 53 NEOUS See eS a a a eee ree SO mi pee wee SPs oped 4 publicationss2eee- 24 tate poet mtorr Neate) 27,28; 31, 56,417,120 POW OV Cree ais 2 la a a eS a a I eee 37 visitors______ ae cide ala he Oi Aa ye ee 31, 56 war .collections 2... 22.23 + 4 Ae aree Th Wa geste hee Nine ee ae 1380 National Park (Services st256_ rset ieee ee een igh aaa fee Ee 24, 32, 58, 59 National... Research, ‘Council {2222 ee ee ee ee ee ee 27 National Society. of the. Colonial Dames == 2 *_ =e Se ae ee eee 41 National Zoological Park ._______-_.-__-_ 4a} 12) 08, 18,,28, 33, 123, 135 ACCOSSLOMS a ee ae ee erp ON 85, 135 animals in, the: collection] S22 = 5 2 aD eee epee eee 91 UG EOTA LATA sa Ie sea pa ee important Meedsiie hs ceil ey ee een te eg ee eee Tee 99 improvements. kath Pen aio hy nei ies, Bad ee ea egelae = et 98 Library. heed ee | ee ae 8 ee eee ee 29, 115 TROVE Bee ce re NEE AC ec ees Cee ee, 89 TOD OU ee ee ee eee 85 SVE COUT oss a a ge ee 97 INavy (Department! - = 2252 2 USN 2 oe 2 a ee ee eee 30, 38, 39 Navy, Secretary of the (member of the Institution) ___-___-__~______-__ A. BN GCE O10 Sry a a ee et ee 36 ING Win GUSe)) SCG nee eee ee le Re pee ee 64 New . York -Botamical’ Garde ee Sea ae en ae eae ED 23, 25, 45 oO. Occult:senses)in; birds, The (Beck) 222 2-==22-42- 45-55) s2e5 bee es 439 Oersteds Dr seme es Nin nde id er RET 45 CMa bree hg Aare nn ra i pe ete tS teen eon eri he gee ee re se 12 Other worlds, The habitability of Venus, Mars, and (Abbot) ----________ 165 12h Padgett, Representative Lemuel P. (Regent)________-______________ 11, 14, 127 Baleontological® fleld vw orks 22 See Soe er ee sae pees eae eee ee 19 Palmer, A. Mitchell, Attorney General (member of the Institution) ______ ta: Ram AMOErI Can (OOM TCS S a are a ei at hare ca eh I po oe Zt Pan American Financial Conference, Bolivian delegates to______________ 46 Parasitism and symbiosis in their relation to the problem of evolution CQL yea Na la a woe ga Cc 399. Bapbenson,) Ml. Wi eee Pe el De Tie ne eee coe arte el ec ee 46 Payne, John Barton, Secretary of the Interior (member of the Institu- (1) 0) 6) \peaeaiaan Rint atener ets tne. Lab icine eee « Sirsa ie arert Siu Oe San Oe 11 Pearce, Prot. See ee a tm en 43, 67, T1 Peking “Union Medical “Colleges 0s see Sea ee a op ee 22 Pell, Rey. Altred. Daa a ae alec ne ra 49 a ee ee ee ee eee ee INDEX. 701 Page pete hi BANOS. Wane ate ee Ee os 45 PeereeecCndelly, ARGOVEE, Widteae aes ee 46 oo SLE 1 eee) EOE SSS oS NN Se ee NT eS t S 82 PPR COC SE) Se he ee eee eee Se Se Le a 128 medee, LUCK 1. aad George Wer TNO 12 i te Sige gedes Postmaster General (member of the Institution)__-.-_ = 11 Rolomac- Blechrnic Hower COs census 52 Lev OES SLIME DB VOTO Dea A ES ods a es Oe ee OTe Rey E I INMIN 2602 Arty 65 POMP ORDO cree en IO OUL Ig eee 1388 President of the United States (member of the Institution)_________ 11, 138, 129 Meee TELM OTE DL LOUIEOTI SOT. ee 8 AS alls pce ad ine nope 28 Printing and publication under the Smithsonian Institution, advisory “SUSLTETEL Ch BETS) (0) ee i Se a ie Et a Pee ee eae eee pe ater ee eee eee 28, 122 Proceedings of the Board of Regents of the Institution__________________ 127 Publications of the Institution and branches____________ 13, 27, 28, 31, 32, 55, 69 RIUROAMISE USD ER A Se eS nN ee OEM mn ant nana MS Ae Oo, 117 NOT ae en ee eo BIO En Ma em alee BASS 4itn Atay ork uta by ¢ 2 LSE AEDS i” pal eel A nc Ga aay CONTE aA a aE EES 46 LESTER GCIs a Tb ed DTaP (CS 0 le ae a oe a Ia lel ae a AS IOs = eng Pha Ue R. Timo ly boen uit 00. 2 i ee Oe 46 Racial groups and figures in the Natural History Building of the Na- me aleeitseums (OUST) == 8 ee PE ae 611 RAPES OTT tn) OTA ee 5 seg LA rs St I ae eg 131 Ralph Cross Johnson collection in the National Gallery at Washington, HMO BANO CHER) ene eS lS ag ne 2 pr ree pe EE thay Se, 679 Ree SCer Sentry -OCOUNet Spr ber Say Aare OT a. A Ae ey pp 49 FEES STS Taped GW a2 Re ed a eee Se 114 meen bun, Or, Richard. 2-95. 25 Ye 2 grat eis Th epee ta: 49 peew ely ede Cee ee es os SS Se Rees a ee 20, 21, 134 Ravenel, W. de C., administrative assistant to the Secretary_____________ 12, 56 Meter Patna Smee te eer a on 36 Regents of the Institution, Board of_-_-.----_-________- ne ee, «ae 14.138 ANNU al meetin ef a a a ie et 127 executive Committee, Report= = Seante- es et ote yh te 123 permanent Committee; reportasseseeen ss eee at ek eee 128 MLEcecdines Otte le. ee ee SR PE a ee 127 eee TITEL PAC OISOT) Viens seme en we Le 17, 123 iReport of tue Secretary of the institution ———— 22 2 eee AS: inexeareh in tropicaliAmericah ere a4: fs old A et Sree ete» sent 27 esearches and explorationg 2220 2.5 2 8 8 Crete yey ye ie peg 18 Resplendent shield-bearer and the ribbed-cocoon-maker: two insect in- habitants of the orchard, The (Snodgrass)... ssn eee 485 71 LARS Te Gea SN A pote EY Shere pty states 17,123 LP COTS ASR CAG EN a aah ah a Lape By ayinm ininature (CW lately yes 2 el ae rp eA es 2, ae Tol cele 389 Ribbed-cocoon-maker, The resplendent shield-bearer and: two insect in- Hap aaAnts of theorchard (Snoderaes) 2. ee oe 2 oe nae lh ety 485 frelon Jor: Charles Vy. on vee ees Bee ek ee oe egal 12,114 Pee KenHCKET Hill wal GO VETO Wei ee Ei es ee a tee 40 eWay.) Ot eOUCLUs 2a = So ceo aE Apt at no tone wears 12 702 INDEX. as Page. Ritschel, Willian aNewAes Ss a8 oy ace pe he eS oe Se eee. ee 49 BiVerss Dre WW EL. Roe Ss a ee Se RE eset ne 54 Meebling; J ODM AS eat ee ee 17, 35, 105, 106 Rogers; Maj. ‘Gen: B dossk ese aS ede or eal See eae ee 42,131 Roosevelt, Col. Theodores.= SS Se ee ee ape a Ee 20, 90 Rose, George B. (The Ralph Cross Johnson collection in the National Gal- Slery-at Washington, D.C.) 222 abe =e en ane POE papa Pe aes 679 Bsa }ste vie) D2 eeeel eb (a ee ge aati ee ON LN BARU Eee aterm etna teed Gr ke a 12 12 Royal Society. of London <3) -2> =o 5 ee eee = eee eee 108, 111 Rusby} Prof. Henry.- Gioh-ts2e2-ady Sy ee dyo tes) oat OE IEE SAS Sa ee 45 S. Safford, W. E. (Daturas of the old world and new: an account of their narcotic properties and their use in oracular and initiatory ceremonies)_ 537 SS Sur i Ge UNM SS, NUD TSS GUL aa as 2 eo ae a 136 Sanford sfound=*Georcer ia." 2a ees oe eee a en ee ee 17, 123 Santo: Domine, (OxpLOra tions in rs ee ee ae a 25 STEW SLEZ=5 a Mel ICO) 11S Se NEG Se See ee ee eee ee 136 ESE HSHE Eel BTA BR IN a PAE a AN PPE OR Pree PR 45 SS claves ths VW Deter ee ee 114 SS CRM Bs, VV e Sa 0 ig a eee ee ee 12 SS (GH LLU op WW cB ig IN a a a a a Pea MP SLESE AGL BLS (53 0 49 Schwart7). DMNA Sat eet ee Osut ey Pea ey Ee a SO 45 Seidmore,..Hliza. Rubamaheo)—- 2. tes ee ees 44 Scud dev,.Ni Paes She se eee ee ee ee 12 Searles, Stanley, editor, Bureau of American Ethnology_____________ 12, 69, 121 Secretary-of thevinstitutions =.=. 3, 11, 12, 36,-55, 56, 72, 84, 100, 107, 111,113, 114) 116, 1220927, 1342135 TOD OUb == -2- pee Se ee ee ee ee 13 supplemental. statementu.2—22 > 253 oe ee ee oe 129 Senses-of insects, ‘The: (McIndoo)/22--+.-.=-=- 2-25 ee ee 461 Seton; Ernest Thompsons @ 2s hs 210) hs Te BR ee a 8 ee ee wee 89 Sewall, -Sieis:22242 22sec eee ce eee eee ae 40 Shantz,- Dr.-H.-E 4222 2a ce ee ee PO OU eit Shs 20 Shapley;- Dr. Harlow2:-=22222--2s22i22 22220). 5 ee Be Pe 53 Shoemaker, C. W., chief clerk, international exchanges____-___________ 12, 84 Sinaloa, Mexican State of, Forestry Commission__~__~_____-____-__-=_+_- 45 Smith, .Joseph:--Sas-2--242s628-lo-sa soho nase eel EN Re 136 Smithson-: funds 2-2 s22222s2s2s2e5s22s55es2essheess ees ek BOSD a 17,123 Smithson, James... 2225-25 se oe BOE yO £0 PURI T Ie Eh Be 13 Smithsonian advisory committee on printing and publication____--____ 28; 122 Sinithsonian.African- expedition... =2=—_-_+. = See ee 20, 184 Smithsonian annual reports foe Ca aes ie eaten 27, 28, 117, 118 Smithsonian Contributions to Knowledge____________~_+_~-______-__ Pat Smal thsonian'-expeditions.2< 2-502. o ete ee ee ee ee 134 RSENS SRN pc ce a ae Be ee ett 20, 134 Borneo—-Celebes—-Australian:222 2222-22222. VR oar ar ee 21, 134 Collins-Garner,” COmzOE UT Cl Lies as eS ETT RE OL = Pe ae eet 20, 134 Saskatchewan. «2.022825. 2205 560 he 3 Ae ee ie Pee eee 19, 134 Smithsonian...ibraty:e 22220523502. lee ee ae 13, 29 MOPO bret ee we RE, eee ee 112 Smithsonian meteorological tables..--_2- 22 ee a INDEX. 703 Page Smithsonian solar observing station: OOS Baa) 0G) ab IGS ae ee ee ee 15, 35 Maonnnerardta Hala, Ariz Se ae 2 a es yee ge a 35 Snodgrass, R. E. (The resplendent shield-bearer and the ribbed-cocoon- maker: two isect mhabitants of ‘the‘orchard) 2-22-22. 485 Soil acidity—its nature, measurement, and relation to plant distribu- HPA eh sO QV BYST ESQ 2) Vee a I ate OE Bere ee EE AS 247 Solar observing station, Smithsonian: COLD ORCI os GH GI eae ee Ree ne a A RS ei aie 8 Oa eae ea SN) ily Sia MIGHT G eax Merle ATi 2S Sa) ce oe eles eee 35 South American historical documents, exhibit of--____________________ 27 Special researches, Bureau of American Ethnology____________________ 65 Sopp BG Bes ite eS Cegak iy a Nee A > NE aN IED a 68 CNP TUCG BLD TNE RE 6S ii cepaah eine a Rt BAS TIRE Ns ae aS A RE REO 68 MSN COT MECN SPhUCl se eS eee ee ee eye oe 2 eee 86 Spier, George W_---_- a EN Ea ae ey eae oy ag 48 (rh TERE SR ce BA | he Gp i an oe eae eer ape, gee a ea Be ae ee fe 24 State, Secretary of (member of the Institution) -~______________________ 11 PRESET eo Cas LCOMlsn Ot rae ee ee ee Ss ne Se 12, 29 Sp SRDS DUA] 0S high eee eae a ee Rhye ys em aan ae I PO OM Ta 43 Structure of crystals, The determination of the (Wyckoff)_____________ 199 OSUTTE DIDS VAS ETRPES Paige] G5 If 0 1S bab a ne es a Ol aaa WEAR Ny oA aapae RSM paE,. Sod NUL RIE 42 Studying the sun’s heat on mountain peaks in desert lands (Abbot) ______ 145 Sun’s heat on mountain peaks in desert lands, studying the (Abbot)____ 145 TES, ELEN tg (A th pee me i dE i Ae AO Ee Es ites Superintendent of the National Zoological Park_-__________________ 12, 29, 100 Suppression of agricultural pests by birds, Local (McAtee)____________ 411 CS OEDLIBS “LES al katate A acl eae eae ale sear NEF 1G in at eh EERIE” ARNON NL Tae aie I 17, 31, 44 PUAN CPRIECOTICCRO RT ere OLIMD SEC cere cree een en aoe eens ah A eae ge ee 12, 61, 62 ay Textiles, collections in the division of, National Museum________________ AT Marea ITMCITIAS tel) 2 Bc) 5 8s es ae Sa oe ee OE, Seer, 45 mnayer, Abbott Hats tacater ys 3 wey blogh eile to aniiiosiles wonlonilons 136 homas, senator Charles §. (Regent)... 2 11, 14 LUT NSONSTS Ta Dery ea Ue Ee I a pee ee ene eee eee eee 71'S EME 27 Treasury; Department, United, States_asitesuartanss a) 2) ee 52 ETP BERGE CELL aot Bete ea 7 NS aa SNE DURA SY oy LID Oe ER eS 45 Treasury, Secretary of the (member of the Institution) —____________+=___ slat airoepical America, researeh : ins 6.2 6 ee ee 27 Mime, W. P. editor of the Institutionsreio!_ sust) eines £ oeliaigde) e 11, 29) 122 SPSPTDTI NEED) WLS LU VV oe st ee Se eT ae ee ee 136 Bee TO bat hy re-run e SUNS ke oo Soe ee Ee ee A ee 173 ise CHENIN 14 5 GEN ee eee ek tee h e aee P 136 as Ulrich, E. O. (Major causes of land and sea oscillations) ___-____------+__ SPA miversal Kilm Manufacturing (Co... .-25.— | 2 eee ee 20, 44, 134 University at Copenhagen, Botanical Museum of the_______--_.------__ 45 MERI VGESIGY TOC Ulin GIS =e. se cl ee Sel ree eS ee i 25 Vy. Venus, Mars, and other worlds, The habitability of (Abbot)-------_____ 165 Werwi st tbat COPY SOSLON) = te een ss De ee ee ek RG SH 5, 704. INDEX. Page. Vice President of the United States (Regent and member of the Insti- CUtLON) =< sees Sere = ee ie Re ere eee ee 1h, 13) 14, 127 Vitaming-+ (Halliburton) asta soe ese eS x se Se ee ee ee ee 241 W. Walcott, Dr. Charles D., Secretary of the Institution__________________ 8, 11,12, 36, 55, 56, 72, 84, 100, 107, 111, 113, 114, 116, 122, 127, 1384, 135 by 0 Oo Red ee a ag een Pee Mg hati Se se 13 SUP PLEMeEN ca ESCH GON CMe eee ene cea Ome en ree 129 Wary COLLECELONS, INALLOMEAL EUS ete Tnn so eee eat ae ago esr a eee 39, 130 War Depattiment, United. States. 29 eee 30, 38, 39, 47, 52, 61 War Risk- Insurance; Bureau heme 6s Oe es ee a oe ee 51, 129 War, Secretary of (member of the Institution) _~___-____-—-¥_____________ al Se, Warren? Siento Comman Ger disc Ree eg aap ee ee ee 39 Washington, Dr. Henry S. (The chemistry of the earth’s crust) ----____ 269 VV TEAM Gece 0 CT se eS i eA eee 15 Wherry, Dr. Edgar T. (Soil acidity—its nature, measurement, and rela- tonto; plan ty CUSED UCEOM Se a ee ee 247 WV HISELS RS ATT) IVE CIN TN Sera ee a Be a ee 136 AIIA Cir eevee (0 E50 RSM NY BREE OR a LNT PSTN Se ON er ee i LD White, Edward Douglass, Chief Justice of the United States (Chancellor aNd ANeMbeMOEPNE ENSEIE ELON) = ee sees ies Ee eee eee 11,13, 14, 127 Wihite; scenery y (hes emt) te 2c ee ee ea ee ee 11, 14, 126, 128, 138 Wiener Capt. « nS ei f ’ f in ‘ Pr J Me aun bd Be 3 . ae . yin 1 a t 4 ’; , ’ iN : A. } bd is | . i ty ' Lf , 4 ‘ ( ‘ i ‘ ‘ I AUEINION INE 14217