pas ee) o ddeicr ties ieee pear ymcorenre ee arya Imprenre ae Sa iageeneeton wy , 5) ms) ‘a ect wih: ee ; f wari PR “aft! ANNUAL REPORT OF THE BOARD OF REGENTS OF THE SMITHSONIAN ENS PDP U TION SHOWING THE OPERATIONS, EXPENDITURES, AND CONDITION OF THE INSTITUTION FOR THE YEAR ENDING JUNE 30 1915 WASHINGTON GOVERNMENT PRINTING OFFICE 1914 i e \ Kh Wego oS 1B Ds heed ba thd FROM THE SECRETARY OF THE SMITHSONTAN INSTITUTION, SUBMITTING THE ANNUAL REPORT OF THE BOARD OF REGENTS OF THE INSTITUTION FOR THE YEAR ENDING JUNE 30, 1913. SMITHSONIAN INSTITUTION, Washington, May 15, 1914. 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, 1913. I have the honor to be, Very respectfully, your obedient servant, Cuaries D. Waxcorr, Secretary. lit “Se =, ¥ 4 vs i fe vig th CONTENTS. Letter irom the Secretary submitting the Annual Report of the Regents to Penerlripjectsior the annual report. ../.24.4 2 eis 5's sens dole ocib 2 sae sels Officials of the Institution and its branches......................222-..2-22-- REPORT OF THE SECRETARY. eT SIMIEHSOMTAIMEM SOLE GOI yo erie eee 2 oe bese tM ul ay VU ey tar ale MORES ba DTISMIMeNG seein yh eeepc y fae SP MERE Aels Sal alii i Vey Nahas Ci ebm Bia nea aN Ren 2) 9 fs Oe eh a a eS ge pee EME ELCONSTC Cra VION Siete rey ee Ee ta Reyes SL ye aes A lr hg Researches and explorations: ibansley Aecrodynamical Laboratory... «2. .22s-/2 = 2 fe nates os Dee. Studies in Cambrian geology and paleontology....................-- Bemopicabsiryey Or Panama 262052572628 el oh! Soeale oka. Sees baovical expeditions in Africa. 2)... c2 ick. o.e fas sc- see eee oueed ERs paet One MME ORTIEO 2 c/a iyns stg eats My 1 UNE Ae dais SE Mes ec ae Eqn SIDErial OXPOUIOM. > jc. heduee bos. cL oer. eens ae Anthropological studies in Siberia and Mongolia... -..... bP Sel ae Biological survey of Panama Canal Zones. oi). 5.025.623 Sy eeke Amchropolories! sbudiesiin Perw. 3.20 see. bs 22s wig ON oe nenearcues tinder the Hodgkins lh und 22). o. 225...) obese ke Sl ee Smithsonian Table at Naples Zoological Station..................-..-- ee amiman hush Bun see hc, cle ro ie). Lok ees oe lane American School of Archeology in China...........2...-2--2-2-.22-- aU PRAISE ssh REMC K Mekl Aes we hiss Distt Stas Se ReS Ue ele aene One LEDS MEN 70010 1 NMEA SIREN ra BA WR eR OE BOA a Se A Neg Sl IN dat Pam levumomionial islets dele hon 22 lye. ae Bic. d ko ne ok wes Saale Wonpresses'and ‘celebrations. . .....0)) 2). .-.2-2..)..-% pe, sp op emer geet Ve eorre) Washineton Memorial Building:.. +... 2922). 4.302822 bed. \bens ee [OF Re DA Sse UTS PEES Se TOI NAGI TS PE Veer ae, ee? ter a ee OI Pe Pereine@renmericnin MhunGlogy,-o. 4.2. Le Pye oes ay ee Ae ee ee Pipermail Ee Rehsamimeny Noy Sal ON Ne ais Ol Wee oes tae ee Se eam el On OO C MMA cs) ce 0. AC tae a) woe le ede a iil i PE RERtae pe MLIBOTVELLOFY Wisin eee Meteo She en fv ribeg Lee tele International Catalogue of Scientific Literature.........--...-..------+----+- Pa Rem EV UCP Neo Wa Nepal aye es ed Wh Se Ned EN SO 2 Sink le peas Appendix 1. Report on the United States National Museum. .............--. 2. Report on the Bureau of American Ethnology........-.....-.-- 3. Report on the International Exchanges...............--.----.-- 4, Report on the National Zoological Park............-.-.-------- Page. yal CONTENTS. Page. Appendix 5. Report on the Astrophysical Observatory. ..................-.-. 87 6: Repertion the bnbrary.,. 222. eee rete ee Oa eaten ane 94 7. Report on the International Catalogue of Scientific Literature.... 101 §:\ Report on the Pablicataons: -3 085) csac jc. eerie een ot tee ean 104 9: Langley Aerodynamical Laboratory: 2020) toe a ee ee 115 GENERAL APPENDIX. The earth and sun as magnets, by George E. Hale...........................-. 145 The reaction of the planets upon the sun, by P. Puiseux...................... 159 Recent progress in astrophysics, by C. G. Abbot........--....2....------20-- 175 ame .earth smacnetism, by Gi A. Bauer so 2iee 22 based eel ee 195 Modern ideas on the end of the world, by Gustav Jaumann .................. 213 Recent developments in electromagnetism, by Eugene Bloch...............-.- 223 Wireless transmission of energy, by Elihu Thomson...................-...--- 243 Oil films on water and on mercury, by Henri Devaux......................- 261 Water and volcanic activity, by Arthur L. Day and E. S. Shepherd........... 275 Mapplesmarks, by Ch. Epry-2. 264026202. eco Se Ue ale ee 307 Notes on the geological history of the walnuts and hickories, by Edward W. EPS ee ie kg bee HENS SU I le a ee 319 The formation of leafmold, by Frederick V. Coville .....................---- 333 The development of orchid cultivation and its bearing upon evolutionary the- Orios. by We Costantino) 75 Sg 0 ck MC COS AUR re i, 346 The manufacture of nitrates from the atmosphere, by Ernest Kilburn Scott... 359 The geologic history of China and its influence upon the Chinese people, by Eliot lackewolder. ‘hae N02 2/ Lue oa Dal a aC es 385 Whe problems.of heredity, by HE. Apert: 22.0. 222520. ee ee 397 Wabitsot fiddier-crabs, by A‘\S. Pearse. 2.2.4 2.05 YoY ee ee 415 The abalones of California, by Charles L. Edwards. .............-.-.......-- 429 The value of birds'to man; by James!Buekland:. 220.2%). 2. (eee Sl eee 439 Experiments in feeding hummingbirds during seven summers, by Althea R. Barina 2 oS) ss a hg ae So OR AR a 459 What the American Bird Banding Association has accomplished during 1912, py oward JH. Cleaves 2 yu oohl Sea Sa 2 2 OCR OS 469 The whale fisheries of the world, by Charles Rabot................----------- 481 The most ancient skeletal remains of man, by AleS Hrdlitka..............---- 491 ‘The redistribution of mankind) by H, N. Dickson: ... 2.....22.0.02 22. eae 553 The earliest forms of human habitation, and their relation to the general devel- apment of civilization, by M.Hoermes) 28202)... Seems asecieee eee oe eee 571 Feudalism in Persia; its origin, development, and present condition, by Jacques MOUNT Oro rs) s o's 2 a'l cee Page re See ye ie a 579 Shintoism and its significance, by K. Kanokogi...............-.---------+-- 607 The Minoan and Mycenaean element in Hellenic life, by A. J. Evans......... 617 FPismeless combustion, by Carleton: Ellis. /y.. ...... 35.2. eee ee 639 Problems in smoke, fume, and dust abatement, by F. G. Cottrell............. 653 Twenty years’ progress in marine construction, by Alexander Gracie.......... 687 Creating a subterranean river and supplying a metropolis with mountain water, by J. Bernard Walker and A. Russel] Bond!.i. 2.) J000..02: Se eae 709 The application of the physiology of color vision in modern art, by Henry G. Keller and J. J.:R. Mackaodsesiguonk Coathac det AL: See ee 723 Fundamentals of housing reform, by James Ford. ........-....-....2-.-0-00- 741 The economic and social réle of fashion, by Pierre Clerget..................-- 755 The work of J. H.:van’t Hoff byiGs Brunaiees 25a ane see eee. Laem 767 LIST OF PLATES. Page. Secretary’s Report: tbe yee sons Sere tela Ne aac 64 Earth and Sun (Hale): [LSS Mey PAS Sa ee 146 Clip ts 32? Ae oh ee ge ge 150 Mpther NG ee ese a 152 LIST fal {pr MS eg are a ea ea 154 Astrophysics (Abbot): [EAST | Son el 178 RE rec eer Utes ee ie a Nene eau a eit 190 Earth’s Magnetism (Bauer): 2 CES LOUD SSS 0 ry ae a 195 BLED CON een) aC mge Sara as <2 S 198 Pl AHeSP a iON eee oes Bll eo Las 204 PARE UM erect: ry skis SNe 206 LETS Ch Ne OU ei eS oe 210 Oil on Water and Mercury (Devaux): Plarpeyilmeeie es reese ives os kd 264 LBLES RE 02 a eee a 266 [Te 2 UEC Ac ee A 268 1 ENE RCSYE) Ces 1s a eH ag 272 Water and Volcanoes (Day and Shep- herd): TE FNS) I DAA a a ey 280 1 EW S'S) a Be AP ae RE 282 APCD G 2 hia cme os LL a 286 LEE GiS SWAT fetal See te ae ae ate ee eg at nd 288 glo 2) i LA a ie Ge 300 6 ELECTRO WES 0 EN ge ee 302 Ripple Marks (Epry): Le Eso A Ir Gea 308 Lee ESg Ste SY aM ee aa fo 312 PARA IR SOR A sick Ms AOA a 314 Plates 9,10...... Ape sal Bah eehebe i 316 Nitrates from Atmosphere (Scott): LET EGE I UO At ae oO a a > 368 1 sy 1 ye a ae 372 Geology of China (Blackwelder): Pabeuisevineene qc elo aes d 386 Lea RSH Fes) 7 SUR A eR Oe a 390 1 2 aE A a De aR 392 eli 2.512 PAs SEER NS be 394 Abalones (Edwards): Pea Ue ee ws tad oe Sk. 438 Bird Banding (Cleaves): SE) ER ets APA ean a i aL NR Rg ea a 478 Whale Fisheries (Rabot): PEA ea emma een Nps I My 2 482 Platerevacoee. Ae ee a Ie 484 Page. Ancient Man (Hrdli¢ka) 1 24 Ff) RNR go as es Se a 496 Plates: 21 Sir aii Gaius edie 2 ato 498 Piste 4 Gi hn he ap erm ee 500 Plate acuminate Bibiana sak 504 Plate if Seach cin era aii ie Bin 506 Plates 8: Oi s05. beeen es ae 508 Plates cls Wile sass se) talon ae 512 Plates oahu pepe el ek eee 514 late vipat od censcih iat Bias 516 Plate LGh hen (uk era ein G02 a a 518 Plates MMS ie OR eee ar apes eae a 520 ded owl Ed peste MeNneay A Bhaskar es 7 8 522 Plates: 20820 as ei ies aie 524 Blatev228. eee oe CR 526 Plates 23 24a wii eid sa Neues ae 528 Plates 25 S26 unig ie) tse eas 530 Plates 27.528 24: sea ae eee 532 Plates 2 ON S0 ek. Sa NSS a ae apne 534 Plates SI=33 oie ast eae 536 Plates 345355 52.2 oe oe eee 538 Platest36; 7 255 she ae aaa 540 Plates: 58339 A. we see 544 Plates 40% 4D Oia. cn 2U) sions 546 Minoan Element (Evans): Plates Dis) eee a aplhoys aN Eaaae 634 Pi stter cr: - SR ae eee 636 Flameless Combustion (Ellis): Plate: ps SU mane OR eee Api 650 Smoke Abatement (Cottrell): Plaitie gsi Wen nh oak eee ie aes 665 Wey Eee MP AR te TOS CS eb re jy ES A 669 Plated: Gace ipl. 2) else ase see 668 Platesia = 75 ee Ae a at 670 Plates Sala ere nails ee aan 672 Plates 9250300 025 00. De ee ea 674 Bllartes 1-31 (a. 08 50 ts aire io aera 676 Platestl 82s a eee 678 Platesi2 225s Goh ae soe eae 680 Plates: 26-29 ee leks es ene 682 Plates'30=37 eae Soe ee 684 Subterranean River (Walker and Bond): Plates M2 eS Se Ree 712 Plates ‘S400 2 122s. te eee 714 Plates's;624.2 koe. a. ee 716 Plates) 7, Sa eee hie eae ees 718 Plates: DLO ws use aN Nae ete 720 Plate Lyi) ue 3 citrate ees ee 720 ee ee Sas y ANNUAL REPORT OF THE BOARD OF REGENTS OF THE SMITHSONIAN INSTITUTION FOR THE YEAR’ ENDING JUNE 30, 1913. SUBJECTS. 1. Annual report of the secretary, giving an account of the opera- tions and conditions of the Institution for the year ending June 30, 1918, with statistics of exchanges, etc. 2. Report of the executive committee, exhibiting the financial affairs of the Institution, including a statement of the Smithsonian fund, and receipts and expenditures for the year ending June 30, 1913. 3. Proceedings of the Board of Regents for the sessions of Decem- ber 12, 1912, and February 13, 1913. 4, General appendix, comprising a selection of miscellaneous mem- oirs of interest to collaborators and correspondents of the Institution, teachers, and others engaged in the promotion of knowledge. These memoirs relate chiefly to the calendar year 1913. Ix THE SMITHSONIAN INSTITUTION June 30, 1913. Presiding officer ex officio.— Wooprow WILSON, President of the United States. Chancellor.—Epwarp DouagLAss WHITE, Chief Justice of the United States. Members of the Institution: Wooprow WILSsoN, President of the United States. Tuomas R. MARSHALL, Vice President of the United States. Epwarp DoucLass WHITE, Chief Justice of the United States. WILLIAM JENNINGS BRYAN, Secretary of State. Witt1AmM Gipss McApboo, Secretary of the Treasury. . LINDLEY MILLER GARRISON, Secretary of War. JAMES CLARK McREYNOLDS, Attorney General. ALBERT SIDNEY BURLESON, Postmaster General. JOSEPHUS DANIELS, Secretary’ of the Navy. FRANKLIN KNIGHT LANE, Secretary of the Interior. DAvip FRANKLIN Houston, Secretary of Agriculture. WiLtiamM Cox REDFIELD, Secretary of Commerce WILLIAM BaucHor WILSON, Secretary of Labor. Regents of the Institution: Epwarp D. WHITE, Chief Justice of the United States, Chancellor. THoMAS R. MARSHALL, Vice President of the United States. Henry Casot Lopcr, Member of the Senate. Avucustus O. Bacon, Member of the Senate. WittisAmM J. Stonr, Member of the Senate. JoHN DauzeLL, Member of the House of Representatives. Scorr Frrris, Member of the House of Representatives. Irvin S. Pepper, Member of the House of Representatives. ANDREW D. WHITE, citizen of New York. ALEXANDER GRAHAM BELL, citizen of Washington, D. C. GEORGE GRAY, citizen of Delaware. CHARLES FI’. CHoatTe, Jr., citizen of Massachusetts. JoHN B. HENDERSON, Jr., citizen of Washington, D. C. CHARLES W. FAIRBANKS, citizen of Indiana. Executive committee.—A. O. Bacon, ALEXANDER GRAHAM BELL, JOHN DALZELL. Secretary of the Institution—CuHaARLES D. WALCOTT. Assistant secretary in charge of the National Museum.—RicHARD RATHBUN. Assistant secretary in charge of Library and Exchanges.—FREpERICK W. TRUE. Chief clerk.—Harry W. DORSEY. Accountant and disbursing agent.—W. I. ADAMS. Editor —A. Howarp CLARK. Assistant librarian.—PavuL BRocKETT. Property clerk.—J. H. HI. x THE SMITHSONIAN INSTITUTION. XI THE NATIONAL MUSEUM. Keeper ex officio.—CHARLES D. Wa tcoTt, Secretary of the Smithsonian In- stitution. Assistant secretary in charge.—RICHARD RATHBUN. Administrative assistant.—W. pr C. RAVENEL. Head curators.—WILLIAM H. HoLMeEs, LEONHARD STEJNEGER, G. P. MERRILL, Curators.—R. S. BASSLER, A. Howarp CLarK, F. W. CLARKE, F. V. COvILLE, W. H. Dati, B. W. EVERMANN, CHESTER G. GILBERT, W. H. HoLMES, WALTER Hoven, L. O. Howarp, ALES HrpiicKa, FREDERICK L. LEwTon, GrorcEe C. Maynarp, G. P. MrrRRILL, GeRRIT S. MILLER, Jr., RIcHARD RATHBUN, ROBERT Ripeway, LEONHARD STEJNEGER, CHARLES D. WALCOTT. Associate curators.—J. C. CRAWFORD, DAviD WHITE. Curator, National Gallery of Art—W. H. Hoimes. Chief of correspondence and documents.—RANDOLPH I. GEARE. Disbursing agent.—W. I. ADAMS. Chief of exhibits (Biology) —JamMers E. BENEDICT. Superintendent of construction and labor.—J. S. GoLpsmMitTH. Editor.—Marcus BENJAMIN. Assistant librarian.—N. P. ScuppEr. Photographer.—T. W. SMILLIE. Registrar.—S. C. Brown. Property clerk.—W. A. KNOWLES. Engineer.—C. R. DENMARK. BUREAU OF AMERICAN ETHNOLOGY. Ethnologist in charge.—F. W. HonGr. Ethnologists—J. WALTER FEWKES, J. N. B. Hewitt, F. W. Hopes, FRANCIS La FLESCHE, TRUMAN MICHELSON, JAMES Moonry, MATILDA Coxr STEVENSON, JOHN R. SWANTON. Special ethnologist.—Lro J. FRACHTENBERG, Honorary philologist.—FRANz BOAS. Editor.—JosEPH G. GURLEY. Librarian.—ELua LEARY. Illustrator.—DrE LANCEY GILL. INTERNATIONAL EXCHANGES. Assistant secretary in charge.—FREDERICK W. TRUE. Chief clerk.—C. W. SHOEMAKER. NATIONAL ZOOLOGICAL PARK. Superintendent.—F RANK BAKER. Assistant superintendent.—A. B. BAKER. ASTROPHYSICAL OBSERVATORY. Director.—C. G. ABBOT. Aid.—F. E. Fowl te, Jr. Bolometric assistant.—L. B. ALDRICH. REGIONAL BUREAU FOR THE UNITED STATES, INTERNATIONAL CATALOGUE OF SCIENTIFIC LITERATURE. Assistant in charge.—LErONARD C. GUNNELL. REPORT OF THE SECRETARY OF THE SMITHSONIAN INSTITUTION CHARLES D. WALCOTT FOR THE YEAR ENDING FUNE 30, 1913, To the Board of Regents of the Smithsonian Institution: GENTLEMEN: I have the honor to submit herewith a report on the operations of the Smithsonian Institution and its branches during the fiscal year ending June 30, 1913, including work placed by Con- gress under the direction of the Board of Regents in the United States National Museum, the Bureau of American Ethnology, the International Exchanges, the National Zoological Park, the Astro- physical Observatory, and the United States Bureau of the Inter- national Catalogue of Scientific Literature. There is also included an outline of work proposed in the Langley Aerodynamical Labora- tory, the establishment of which has been authorized by the Board of Regents under a grant from the Hodgkins fund of the Institution. The general report reviews the affairs of the Institution proper and briefly summarizes the operations of its several branches, while the appendices contain detailed reports by the assistant secretaries and others directly in charge of various activities. The reports on operations of the National Museum and the Bureau of American Ethnology will also be published as independent volumes. THE SMITHSONIAN INSTITUTION. THE ESTABLISHMENT. The Smithsonian Institution was created an establishment by act of Congress approved August 10, 1846. Its statutory members are the President of the United States, the Vice President, the Chief Justice, and the heads of the executive departments. THE BOARD OF REGENTS. The Board of Regents consists of the Vice President and the Chief Justice of the United States as ex officio members, three _ Members of the Senate, three Members of the House of Representa- tives, and six citizens, “two of whom shall be resident in the city 44863°—sm 1918——1 1 2 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. of Washington, and the other four shall be inhabitants of some State, but no two of them of the same State.” In regard to the personnel of the board it becomes my sad duty to record the death on October 30, 1912, of its Chancellor, James Schoolcraft Sherman, Vice President of the United States. Resolu- tions in memory of Chancellor Sherman were adopted by the Regents at their annual meeting on December 12, when the Hon. Edward D. White, Chief Justice of the United States, was elected Chancellor of the Institution. Dr. Andrew D. White was reappointed as Regent to serve until June 26, 1918; the Hon. Charles W. Fairbanks to serve until July 3, 1918; and Judge Gray to serve until February 7, 1919. Senator Bacon was reappointed a Regent, and Senator William J. Stone was appointed to succeed the Hon. Shelby M. Cullom, whose term as United States Senator expired in March, 1913. The Hon, Thomas R. Marshall, Vice President of the United States, became a Regent on March 4, 1913. 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; Augustus O. Bacon, Member of the Senate; William J. Stone, Member of the Senate; John Dal- zell, Member of the House of Representatives; Scott Ferris, Mem- ber of the House of Representatives; Irvin S. Pepper, Member of the House of Representatives; Andrew D. White, citizen of New York; Alexander Graham Bell, citizen of Washington, D. C.; George Gray, citizen of Delaware; Charles F. Choate, jr., citizen of Massachusetts; John B. Henderson, jr., citizen of Washington, D. C.; and Charles W. Fairbanks, citizen of Indiana. Regular meetings of the Board of Regents were held on December 12, 1912, and February 18, 19138, and a special meeting on May 1, 1913. The minutes of these meetings 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. The annual financial report of the Executive Committee has also been issued in the usual form, and a detailed statement of disbursements from Government appropria- tions under the direction of the Institution for the maintenance of the National Museum, the National Zoological Park, and other branches will be submitted by the secretary to Congress in compli- ance with the law. GENERAL CONSIDERATIONS. The activities of the Smithsonian Institution under its plan of organization cover practically the entire field of the natural and physical sciences, as well as anthropological and archeological re- REPORT OF THE SECRETARY. 3 searches. The Institution was founded for the increase and dif- fusion of knowledge. It is an Institution of record, research, and education, and also of cooperation. It offers facilities for the ad- vancement of human knowledge through original research and in- vestigation in every field and educates the people through the pub- lication of the results of such researches. There is reciprocal cooperation between the Smithsonian Institution and the several departments of the United States Government and learned societies in this country and abroad in carrying forward important explora- tions and lines of investigation. Some of the scientific studies originating with the Smithsonian Institution in this country have since developed into distinct and important bureaus and departments of the Government. The influ- ence of the Institution is world-wide; through its international ex- change service alone it is in correspondence with more than 60,000 individuals and learned societies'in the United States and prac- tically in every land on the globe. During its entire existence there has been an unbroken record of friends intercourse with every agency devoted to the encouragement of learning. As was said in 1896, by the late Dr. Daniel Coit Gilman, “ Without any Puibonaee) Santen the power to bestow much pecuniary assistance, * * the Smithsonian has been, and is, the great auxiliary of science and education throughout the length and breadth of the land.” The extent of the activities of the Institution is limited only by the amount of the funds available. During recent years its private income has been supplemented on several occasions by friends of the Institution who have generously provided the means for carrying on certain explorations and lines of research, but opportunities for further important work constantly arise which must be declined or temporarily held in abeyance. Some of the projects proposed are such as could not properly be carried on through Government appro- priation, but which the Smithsonian Institution could readily under- take were the means available. Research Corporation—The work of the Research Corporation, organized primarily for handling the Cottrell patents offered to the Institution for the benefit of research, has been progressing steadily during the year. As explained in detail in my last report, this cor- poration was organized February 8, 1912, under the laws of the State of New York as a means of furthering scientific and technical research. It objects as stated in its prospectus are: First, to acquire inventions and patents and to make them more available in the arts and industries, while using them as a source of income, and, second, to apply all profits derived from such use to the advancement of technical and scientific investigation and experimentation through the agency of the Smith- sonian Institution and such other scientific and educational institutions and societies as may be selected by the directors. For these purposes the corpora- 4 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. tion has been capitalized at $20,000, divided into 200 shares, but the charter provides that no dividends shall be paid and that the entire net profits shall be devoted to research, all the stock being held under a stockholders’ agree- ment, which recites that the corporation has been organized for the purpose of aiding and encouraging technical and scientific research, and not for personal or individual profit. At the present time many discoveries are constantly being made, which un- doubtedly possess a greater or less potential value, but which are literally being allowed to go to waste for lack of thorough development. This is due, in some cases, to the fact that the inventors are men in the service of the Government or in the universities or technical schools, who are retarded either by official positions, lack of means, or reluctance to engage in commercial enterprises, and in other cases to the fact that a discovery made incidentally in the labora- tory of a manufacturing corporation does not lend itself to the particular pur- pose of such corporation. ‘True conservation demands that such by-products as these shall be developed and utilized to the fullest extent of which they are capable. The Research Corporation aims to supply this demand and, through the cooperation of the Smithsonian Institution and the universities, to carry forward the work of investigation alréady begun by others upon lines which promise important results and to perfect such inventions as may prove to possess commercial value, thus bringing scientific institutions into closer rela- tions with industrial activities and furthering the improvements of industrial processes. The establishment of the Research Corporation was rendered uo mediately possible by the acquisition, through the gift of Dr. F. G! Cottrell, of the United States Bureau of Mavies! and his associates, of a nob set of patents relating to the precipitation of dust, anges and chemical fumes by the use of electrical currents. These devices are in operation in several States, and are fully described i in ‘an’ ‘ar- ticle in Industrial and Engineering Chemistry, for August, 1911: A number of other patents in various fields of industry have been offered by officers of the Government and scientific institutions, as well as by manufacturing corporations holding paténts not available for their own purposes, and undoubtedly there are many others, both in this country and abroad, who will be glad to have their inventions utilized for the benefit of scientific research. The Smithsonian Insti- tution is interested in the management of this corporation through the membership of the secretary in its board of directors, which is composed of business and professional men, many of whom have had experience in large industrial and mining enterprises. The George W. Poore bequest.—By the terms of the will of the iate George W. Poore, of Lowell, Mass., who died December 17, 1910, the Smithsonian Institution becomes his residuary legatee. As men- tioned in my 1910 report, the estate, estimated at about $40,000, is bequeathed under the condition that the income of this sum should be added to the principal until a total of $250,000 should have been reached, and that then the income only should be used for the pur- poses for which the Institution was created. The estate is still in process of settlement by the executors, REPORT OF THE SECRETARY. 5 As a reason for making this bequest to the Smithsonian Institution, Mr. Poore in his will says: “ I make this gift not so much because of its amount as because I hope it will prove an example for other Americans to follow, by supporting and encouraging so wise and beneficent an institution as I believe the Smithsonian Institution to be, and yet it has been neglected and overlooked by American citizens.” The Kahn Foundation—The Smithsonian Institution is closely allied with a number of organizations and movements of importance to the public through the membership of the secretary in various boards of trustees. Some of these are mentioned elsewhere in this report and among others are the Carnegie Institution of Washington, with whose administration the secretary has been connected since its establishment, and “ The Kahn Foundation for the Foreign Travel of American Teachers.” The last-named organization was founded in 1911 through a deed of gift and trust between Albert Kahn, of Paris, France, of the first part, and Edward D. Adams, Nicholas Murray Butler, Henry Fairfield Osborn, of New York; Charles W. Eliot, of Cambridge; and Charles D. Walcott, of Washington, of the second part. The founder had heretofore established certain trust funds in France, Germany, Japan, England, and other countries for the purpose of defraying the expenses of teachers and supplying them with what he termed “ bourses de voyage” so as to enable them to travel, observe, and study in foreign countries. He believes “ that the cause of civilization may be greatly encouraged and promoted by travel on the part of teachers, scholars, and investigators, and that, by the study and. comparison of national manners and customs, and of political, social, religious, and economic institutions of foreign coun- tries, they will become better qualified to teach and to take part in the instruction and education of the people of their own nation.” In the selection of beneficiaries of the Kahn Foundation preference is given to professors of American colleges or universities and, as a rule, the itinerary is expected to involve an absence from America of at least a year. The limited size of the fund does not permit the granting of more than two or three fellowships each year. FINANCES. The permanent fund of the Institution and the sources from which it was derived are as follows: Deposited in the Treasury of the United States. BeMeseO La STMUUNSOM lee Ge mee wae a ee a Eee ee $515, 169. 00 Resmusrywlesacy Of Smithson, 86F=225 = = + ee 26, 210. 63 DEVOSit troMmEsavings, of InCOMe? 186i 2222250 Jee ee ee ee 108, 620. 37 Bequest on sames; Hamibtton., 1S fia22= 28 ee ee $1, 000 Accumulated interest on Hamilton fund, 1895______________ 1, 000 2, 000. 00 6 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. Bequestiof, Simeon Habel 1 SSO ae ne a eR RE NSU pale Rie $500. 00 Deposits from proceeds of sale of bonds, 1881_---_________________ 51, 500. 00 Giftrof Thomas G. Hodrkins) 1801s Sas ee eee 200, 000. 00 Part of residuary legacy of Thomas G. Hodgkins, 1894___________ 8, 000. 00 DepOsit trom) Saving svoL Income; 100502 = eae eee eee eee 25, 000. 00 Residuary legacy of Thomas G. Hodgkins, 1907___________________ 7, 918. 69 Deposit from: savings of incomes tOlj2s 2 =e eee 636. 94 Bequestiof William (Jones hhees Ol Sls sss Nee ee a ee ee 251. 95 Deposit of proceeds from sale of real estate (gift of Robert Stanton ACV TEVA) aL ee I BR TR NRL A ne Pe ee 9, 692. 42 Total amount of fund in the United States Treasury_______ 955, 500. 00 OTHER RESOURCES. Registered and guaranteed bonds of the West Shore Railroad Co., part of legacy of Thomas G. Hodgkins (par value) —--_--________ 42, 000. 00 oh Roy ez RE of sy pan ee i KS) aU get DOUG Lie sume eet TES as Sy a 997, 500. 00 There were originally four pieces of real estate bequeathed to the Institution by the late R. S. Avery, but during the year one of these pieces and a part of another were sold and the proceeds added to the permanent fund. The real estate owned by the Institution is free from taxation and yields a nominal rental. That part of the fund deposited in the Treasury of the United States bears interest at 6 per cent per annum, under the provisions of the act organizing the Institution and an act of Congress approved March 12, 1894. The rate of interest on the West Shore Railroad bonds is 4 per cent per annum. The income of the Institution during the year, amounting to $92,870.74, was derived as follows: Interest on the permanent foun- dation, $58,875.12; contributions frgm various sources for specific purposes, $16,575.50; and from other miscellaneous sources, $17,920.12 ; all of which was deposited in the Treasury of the United States to the credit of the current account of the Institution. With the balance of $33,060.09 on July 1, 1912, the total resources for the fiscal year amounted to $125,930.83. The disbursements which are given in detail in the annual report of the executive com- mittee, amounted to $92,289.43, leaving a balance of $33,641.40 on deposit June 30, 1918, in the United States Treasury. The Institution was charged by Congress with the disbursement of the following appropriations for the year ending June 30, 1913: Prenat Oma Ox Cla 10 yee aa Ee EL $32, 000 American ethnology222 42322 es eee eens 42, 000 ASTRODHY SICA -ObSenvato lyases 3 is hu ei ae eens 13, 000 National Museum: 3 OL Murniburecand shite sme = ween ee Jie. Leia eles 50, 000 eating ame): Verb tis gees se ee eh 50, 000 Preservation:of collections {222 2--—- 2220 22> eee ee 300, 000 I 200) :¢: ae seed omer ee eer a ONE Reem NEE eyo) UE Lh Se 2, 000 OS ea Oc as hg RR RAN Nas aT a a 500 REPORT OF THE SECRETARY. i PN Histo Tie le OO LO SL Crk: eis iw eee CANOE AAT SR ULE Ss ee $100, 000 Bridge over Rock Creek, National Zoological Park_-_______-__-____-_ 20, 000 International Catalogue of Scientific Literature_____________________ 7, 500 BUGS EH a I a A ea Se eR Sa ae 627, 000 {n addition to the above specific amounts to be disbursed by the Institution, there was included under the general appropriation for public printing and binding an allotment of $74,900 to cover the cost of printing and binding the annual report and other Government publications issued by the Institution, and to be disbursed by the Public Printer. RESEARCHES AND EXPLORATIONS. The Smithsonian Institution has continued to carry on field work in various lines throughout the world by means of small allotments _ from its funds. It has also accomplished a great deal in the way of exploration and research through the generosity of frienas of the Institution, who have contributed funds for special work or provided opportunities for participation in explorations which they had under- taken personally or through the aid of others. Each year, however, the Institution is obliged to forego opportunities for important in- vestigations through lack of sufficient funds. I can here only briefly mention some of the explorations and re- searches in progress during the past year. Accounts of activities connected with the Astrophysical Observatory, the Bureau of Ameri- can Ethnology, and the United States National Museum are given in other parts of this report by those in direct charge of those branches of the Institution. LANGLEY AERODYNAMICAL LABORATORY. At a meeting of the Board of Regents on May 1, 19138, the follow- ing resolutions were adopted: Whereas the Smithsonian Institution possesses a laboratory for the study of questions relating to aerodynamics, which has been closed since the death of its director, the late Dr. S. P. Langley, formerly Secretary of the Smithsonian Institution; and Whereas it is desirable to foster and continue, in the Institution with which he was connected, the aerodynamical researches which he inaugurated ; Resolved, That the Board of Regents of the Smithsonian Institution hereby authorizes the Secretary of the Institution, with the advice and approval of the executive committee, to reopen the Smithsonian Institution laboratory for the study of aerodynamics and take such stens as in his judgment may be necessary to provide for the organization and administration of the laboratory on a per- manent basis. That the aerodynamic laboratory of the Institution shall be known as the Langley Aerodynamical Laboratory. That the functions of the laboratory shall be the study of the problems of aerodromics, particularly those of aerodynamics, with such research and ex- 8 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. perimentation as may be necessary to increase the safety and effectiveness of aerial locomotion for the purposes of commerce, national defense, and the wel- fare of man. That the secretary is authorized to secure, as far as practicable, the co- operation of governmental and other agencies in the development of acrogrom: ical research under the direction of the Smithsonian Institution. The Regents also authorized the secretary to appoint an advisory committee; to add, as means are provided, other laboratories and agencies; to group them into a bureau organization; and to secure the cooperation with them of the Government and other agencies. In accordance with the above general plan an advisory committee was organized at a meeting convened at the Institution on May 23, 1913. The official status, organization, agencies, resources, and facilities of this committee are set forth in a statement reprinted in the appendix to the present. report. In preparing plans for carrying forward investigations in various lines a study is being made of researches in progress in other coun- tries, and an allotment has been made from the Hodgkins fund for the maintenance, in part, of the laboratory. STUDIES IN CAMBRIAN GEOLOGY AND PALEONTOLOGY. During the field season of the fiscal year 1912-13, or the spring and summer of 1913, I continued my geological work in the Canadian Rockies. A month was spent in the Robson Park district of British Columbia, and Jasper Park, Alberta, our camp being on the conti- nental divide near Berg Lake, northwest of the Yellowhead Pass, through which the Grand Trunk Pacific and Canadian Northern Railways have beens built. Considerable collections of fossils were made at several localities, photographs were taken, and several places in the geological section studied in 1912 were examined. This was rendered necessary by reason of my having been driven out of the region by continued rain and snow storms the previous year. From the Robson district I went to Burgess Pass, north of Field, British Columbia, and worked at the Middle Cambrian fossil quarry until late in the season. Both in the Robson district and also at Bur- gess Pass I was assisted by my two sons, Sidney and Stuart, who have had many years’ experience in field work in the Rocky Moun- tains. Mr. R. D. Mesler, of the United States National Museum, spent nearly the entire field season collecting at Burgess Pass. Special effort was made to finish collecting at this famous locality, and at the close of the field season a collection of several thousand specimens weighing over two and a half tons was shipped to Wash- ington. REPORT OF THE SECRETARY. 9 GEOLOGICAL SURVEY OF PANAMA, A plan has been formulated and some progress has been made in certain lines of field work for a geological survey of Panama, under the joint auspices of the Isthmian Canal Commission, the United States Geological Survey, and the Smithsonian Institution, and an allotment has been made from the Institution’s funds toward the ex- penses of such investigation. The general plan of the survey com- prises a systematic study of the physiography, stratigraphy and structural geology, geologic history, geologic correlation, mineral re- sources (including coal, oil, and other fields), petrography and pale- ontology of the Canal Zone, and of as much of the adjacent areas of the Isthmian region as is feasible. In this survey an opportunity is afforded for working out in detail the succession of the geologic for- mations and the study of the structure, petrography, and paleontology of a Central American area such as has never before existed, and probably never will be realized again. It is possible to make and properly characterize a standard geologic section of this part of the world, one with which the more obscure exposures of adjacent areas may be compared. ‘There is already nearly completed a section of each side of the Culebra Cut in a horizontal scale of 1: 5,000, vertical seale 1: 2,500; and a general section has been made from the Atlantic to the Pacific, with collections from every fossiliferous exposure seen. A basis has been practically determined for the intercorrelation of the formations across the Isthmus and for correlation with the Gulf States, also with certain formations in some of the West Indian Islands. Upon the completion of this survey the Institution will publish a general account of the work accomplished, and later it is planned to print a detailed report of the geological data of the Isthmus and adjoining regions. BIOLOGICAL EXPEDITIONS IN AFRICA. Rainey African expedition—The Paul J. Rainey expedition in British East Africa came to a successful close in February, 1912. The collections, numbering 5,750 large and small mammals, 400 birds, 2,000 reptiles, and 500 miscellaneous specimens, included a large number of new genera and species since described in the publications of the Institution and the National Museum. During this expedition Mr. Edmund Heller, of the National Museum, who had previously served as naturalist on the expedition under Col. Roosevelt, was the guest of Mr. Rainey, who provided him all the native assistants that he could use, and accorded him perfect freedom as regards choice of collecting ground. Mr. Heller was thus able to visit the exact regions from which material was most needed to supplement that procured 10 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. by the previous expedition. After studying the mammals in the British Museum, Mr. Heller reports that the United States National Museum now has the finest series of East African mammals in the world. Eighty lions were secured on the expedition, which more than tripled the highest previous record for Africa. The Childs Frick Expedition—As mentioned in my last report, Dr. Edgar A. Mearns, United States Army, associate in zoology in the National Museum, who had served on the expedition under Col. Roosevelt, accompanied Mr. Childs Frick, of New York, on a hunt- ing and collecting trip in the territory north of that visited by Col. Roosevelt and Mr. Rainey, covering at the same time certain parts of Abyssinia, northern British East Africa, and the country lying about Lake Rudolf. The expedition ended in September, 1912. The col- lections as a whole embraced plants, mammals, birds, reptiles, batra- chians, fishes, mollusks, crustaceans, and other invertebrates. A part of the large collection of birds obtained by this expedition is deposited in the National Museum. EXPLORATIONS IN BORNEO. Abbott Borneo expedition —Through the generosity of Dr. W. L. Abbott, who for many years was engaged in natural history and ethnological ‘investigations in the Malay Archipelago, a fund has been provided for natural history field work in Dutch East Borneo. Nothing has been published concerning this practically unknown region, and the National Museum had no collections from East Borneo, although there were a few from the west and south coasts of Borneo. During the past year Mr. Raven, in charge of this exploration, succeeded in securing a very interesting series of the characteristic mammals of the country, such as orangs, deer, wild pigs, squirrels and smaller rodents, and other interesting species. Mr. Streeter’s exploration in Borneo.—Mr. Daniel Denison Streeter, jr., of Brooklyn, having offered his services as a collaborator in zoology of the National Museum, sailed from New York on April 4, 1912, and returned December 24, 1912. Some of his thrilling experi- ences in the interior of Borneo are described in his interesting report to the Institution. He passed from Sarawak into Dutch Borneo by ascending the Rejang River and crossing the mountains on the dividing line to the Kajan River. He then ascended to the head of this river and crossed another range to the headwaters of the Mahakam River, which he descended to the Strait of Macassar. During his trip he secured some interesting collections of mammals, reptiles, and anthropological specimens, part of which have been received by the Museum, but many additional specimens were neces- sarily left behind in the mountains and may not be recovered. REPORT OF THE SECRETARY. ai In describing his journey Mr. Streeter writes: Arriving at Kuching, the capital of the Kingdom of Sarawak, in north- western Borneo. I apprised the officials of my plan to cross Borneo. They helped me with every means in their power, although they told me that no man had ever yet been across Borneo, and that they did not think it possible for me to do it. * * * JT erossed a bay 200 miles wide in a Chinese junk to the mouth of the Rejang River. Here I engaged three Malays aud their canoe to take me S80 miles up the river to the island of Sibu. * * * A little Malay river steamer arrived and took me 90 miles farther up the river—as far as it could go. At this head of navigation is a little native town called Kapit, and here I again took to dugout canoes, this time for good and all. * * * It took me two months to ascend this river to its headwaters. I collected specimens of reptiles and mammals, together with interesting anthropological specimens, took photographs of all kinds, studied the natives, the rivers, the weather, vegetable life in general, made notes on everything, and mapped my course as accurately as I could with the instruments in my possession. * %* * T crossed the main range of mountains forming the backbone of Borneo to the headwaters of the Kajan River. I estimate the altitude of the pass through which I crossed the mountains at a little over 3,000 feet. * * * [He then proceeded] in dugout canoes down one branch of the Kajan River and up the main river for several days to the immense village of Long Nawong. This village comprises about 3,000 souls, ruled by a native rajah, who visited me and with whom I exchanged presents. Here I set out with one canoe and five head-hunters as paddlers and continued up the Kajan River. A flood arose, my canoe went to the bottom, and we had to swim for shore. I saved my rifle and my tin box of maps, papers, diaries, and notes. Continuing on foot up the river we fell in with a party of 40 head-hunters of the Bahau Tribe and I arranged to travel with them, sending back my five Kajan paddlers. With this Bahau troupe I continued up the Kajan River to its headwaters and over another range of mountains to the headwaters of the Mahakam River. * * * After losing my collection I immediately began a second collection, and this assumed the proportions of the first as I proceeded. When within about 500 miles of the mouth of the Mahakam River I came to the first outpost of civilization, the Dutch military post of Long Iram, in charge of a Dutch captain and a company of native Javanese. Upon hearing my story the captain promised to send a military expedition up into the interior, where the Dutch had never been before, and try and secure the outfit which I had left at these native villages. * * * I boarded a little flat- bottomed Malay river steamer, which * * * floated on down the river to the coast. LYMAN SIBERIAN EXPEDITION. The expedition to the Altai Mountains, which was financed by Dr. Theodore Lyman, of Cambridge, Mass., as mentioned in my last report, returned to Washington September 16, 1912. Mr. Ned Hollister, a naturalist of the National Museum, accompanied Dr. Lyman. The expedition resulted in securing 350 mammals for the National Museum and 300 birds for the Museum of Comparative Zoology, Cambridge. The region covered was in the Kurai dis- trict, Government of Tomsk. The mammal collection is one of the most important received in recent years, as the region had not been represented in the Museum, and the fauna was of special interest on account of its close relationship with that of North America. 12 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. ANTHROPOLOGICAL STUDIES IN SIBERIA AND MONGOLIA. With the view of securing further information as to the origin of the race that peopled America, a visit was made to certain portions of Siberia and Mongolia by Dr. Hrdlicka, of the National Museum, dur- ing the summer of 1912. This work was undertaken partly under the auspices of the Smithsonian Institution and partly in the interest of the Panama-California Exposition of San Diego. Besides field observations made by Dr. Hrdlicka, an examination was made of the anthropological collections in the various Siberian museums in the region covered. He saw or was told of thousands upon thousands of burial mounds, or “ kourgans,” dating from the present time back to the period when nothing but stone implements were used by man in those regions. And he saw and learned of numerous large caverns, particularly in the mountains bordering the Yenisei River, which yield human remains and offer excellent oppor- tunities for investigation. A brief account of Dr. Hrdli¢ka’s studies is given by him in a pamphlet published in the Smithsonian Miscellaneous Collections, in which he says: In regard to the living people, the writer had the opportunity of seeing nu- merous Buriats, representatives of a number of tribes on the Yenisei and Aba- can Rivers, many thousands of Mongolians, a number of Tibetans, and many Chinese, with a few Manchurians. * * * Among all these people there are visible many and unmistakable traces of admixture or persistence of what appears to have been the older population of these regions, pre-Mongolian and especially pre-Chinese, as we know these nations at the present day. Those representing these vestiges belong partly to the brachycephalic and in a smaller extent to the dolichocephalic type, and resemble to the point of identity Amer. ican Indians of corresponding head form. * * * The physical resemblances between these numerous outcroppings of the older blood and types of northeastern Asia and the American Indian can not be re- garded as accidental, for they are numerous as well as important, and can not be found in parts of the world not peopled by the yellow-brown race; nor can they be taken as an indication of American migration to Asia, for emigration of man follows the laws of least resistance or greatest advantage, and these conditions surely lay more in the direction from Asia to America than the reverse. In conclusion, it may be said that from what he learned in eastern Asia, and weighing the evidence with due respect to other possible views, the writer feels justified in advancing the opinion that there exist to-day over large parts of eastern Siberia, and in Mongolia, Tibet, and other regions in that part of the world, numerous remains, which now form constituent parts of more modern tribes or nations, of a more ancient population (related in origin, perhaps, with the latest paleolithic EHuropean), which was physically identical with and in all probability gave rise to the American Indian. BIOLOGICAL SURVEY OF THE PANAMA CANAL ZONE. The biological survey of the Panama Canal Zone, organized by the Institution in 1910, was brought to a close during the past year as REPORT OF THE SECRETARY. 13 far as field work was concerned, and some of the results have been published. ‘The natural history collections made by the survey have added very valuable material to the National Museum series of mammals, birds, fishes, reptiles, and amphibians, land and fresh- water mollusks, flowering plants and ferns, and specimens of micro- scopic plant and animal life. ANTHROPOLOGICAL STUDIES IN PERU. During the past year a second trip was made to Peru by Dr. Hrdlicka in continuation of the brief but very interesting researches made by him in that country in 1910. The principal objects of the trip were the mapping out as far as possible of the anthropological distributions of the prehistoric Peruvian, more particularly the coast people; the determination of the physical type of the important Nasca group of people, which represent one of the highest American cultures; further inquiry as to man’s antiquity on the west coast of South America; and the extension of Dr. Hrdlitka’s researches on pre-Columbian pathology. Important collections were made for the National Museum, as well as for the Panama-California Exposition at San Diego. A very perceptible change for the worse was observed in the state of preservation of the ancient remains, both skeletal and archeological. Dr. Hrdlicka reports: The major part of the old population of the extensive coast region were found everywhere to belong to the brachycephalic type, intimately related to the Maya-Zapotec type in the north. The Nasca people were one of the purest groups belonging to this type. Wherever they lived these people of the Peru- vian coast were wont to practice, more or less, the anteroposterior head deforma- tion. They have spread along the valleys to the foothills of the Cordillera, and have probably in some instances penetrated into the mountains. Meanwhile, however, they became in many though not all localities more or less mixed, or rather mingled, with dolicho or near dolichocephalic elements which came from or across the mountains. As to man’s antiquity, the results were wholly negative; no trace of man of geological age, nor even of an ancient man of the present epoch, were discovered. The density of the pre-Columbian population was in some localities greater, in others probably less, than at the present time. As to pathology, the people of the mountains were found to have been much healthier than those of the coast. The most common disease leaving its traces on the bones in ancient Peru was arthritis. In strictly pre-Columbian ceme- teries there was no rachitis, syphilis, tuberculosis, or cancer. Wounds of skull were very common. In the mountains numerous interesting instances of tre- panation were discovered. Further explorations in the mountainous parts of Peru are urgent. RESEARCHES UNDER THE HODGKINS FUND. As mentioned in my last report, a limited grant was made from the Hodgkins fund for carrying on certain observations on nocturnal radiation at various altitudes. The results of this research, as also 14 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. of several other lines of investigation in connection therewith, pro- vided for by an additional grant, are discussed on another page by Mr. Abbot in his report on the Astrophysical Observatory. There was also allotted from the Hodgkins fund a grant for carrying on aeronautical researches in connection with the Langley Aerodynami- cal Laboratory, discussed in other paragraphs. There was in press at the expense of this fund during the year a paper by Dr. Leonard Hill and associates, discussing the results of important researches made by them in London on the influence of the atmosphere of crowded places upon our health and comfort. SMITHSONIAN TABLE AT NAPLES ZOOLOGICAL STATION. In order to afford an opportunity for American biologists to study marine life under exceptionally favorable facilities, the Institution for 20 years past has maintained a table at the Naples Zoological Station. Investigators are assigned the use of this table for stated periods on the recommendation of an advisory committee appointed for the purpose. The authorities of the station have on several oc- casions courteously allowed more than one occupant of the table when there was overlapping in periods of appointment. During the year covered by the present report Mr. Sidney I. Kornhauser and Mr. Edward C. Day, both of Harvard University, have pursued studies at the Smithsonian table. THE HARRIMAN TRUST FUND. Under a special trust fund, established by Mrs. E. H. Harriman, for his investigations in natural history and ethnology, Dr. C. Hart Merriam has equipped two offices, the principal one at Washington, D. C., the other at Lagunitas in west central California, a convenient center for field work on the Pacific coast and a favorable place for the preparation of results. His principal work during the year has been a continuation of a monographic study of the American bears. Assistance in the way of the loan of specimens has been rendered by all of the larger museums of America, including the Government museums of Canada, at Ottawa and Victoria, and by a number of sportsmen and hunters, who have placed their private material at his disposal. This has been still further augmented by the purchase of specimens, mainly skulls, of rare and little known species, some of which are the only ones in existence. In view of the fact that several species of our large bears are already extinct and others on the verge of extinction, the great value of this material is obvious. In connection with the study of the big bears a new method has been developed, namely, an intensive study of teeth from photo- graphs. Owing to the large size of bear skulls, it is impossible to REPORT OF THE SECRETARY. 15: bring the teeth of several individuals near enough together to admit a direct comparison. To obviate this difficulty, the teeth have been photographed natural size. Series of these photographs arranged closely side by side permit direct critical comparison of a number of specimens at one time, favoring the recognition of resemblances and differences not easily detected from the specimens. This method would seem to be available in the case of other groups of large mammals. Owing to the desirability of completing the study of the bears as early as possible, but little field work was undertaken. Still, a few tribes of Indians were visited, and half a dozen vocabularies col- lected, completing the series of vocabularies of the 25 existing lin- guistic stocks of California and Nevada. AMERICAN SCHOOL OF ARCHEOLOGY IN CHINA. At a meeting held at the Smithsonian Institution on January 38, 1913, there was discussed the establishment of an American school of archeology in China. The objects of the school as proposed are: (1) To prosecute archeological research in eastern China; (2) to afford opportunity and facilities for investigation to promising and exceptional students, both foreign and native, in Asiatic archeology ; and (3) to preserve objects of archeological and cultural interest in museums in the countries to which they pertain in cooperation with eXisting organizations, such as the Société d’Ankor, ete, The management of the affairs of the school was placed in the hands of an executive committee of five, consisting of Dr. Charles D. Walcott, Secretary of the Smithsonian Institution; Mr. Charles Henry Butler, reporter of the United States Supreme Court; Dr. Harry Lane Wilson, of Johns Hopkins .University; Mr, Charles L. Freer, of Detroit; and Mr. Eugene Meyer, jr., of New York. The general committee consists of 15 gentlemen especially interested in archeological research in China, with Dr. Walcott as chairman and Mr. Butler as secretary. Arrangements were made for a preliminary survey in the Chinese Republic for the information of the general committee in considering the permanent organization of the proposed school. PUBLICATIONS. The publications issued by the Smithsonian Institution and its branches during the last fiscal year made a total of 6,260 printed pages, and the aggregate distribution comprised 182,883 copies of pamphlets and bound volumes. The Institution accomplishes one of its principal objects, “the diffusion of knowledge,” by means of its several series of publications which record results of original researches, accounts of explorations, the progress achieved in science and industry, and general informa- 16 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. tion in all branches of human knowledge believed to be of value to those interested in the promotion of science and the welfare of man. The Smithsonian Contributions to Knowledge, in quarto form, and the Smithsonian Miscellaneous Collections, in octavo, are printed at the expense of the Smithsonian fund, and necessarily in limited editions, being distributed chiefly to certain large libraries through- out the world, where they are available for public reference. The Smithsonian Annual Report, however, is printed at the expense of congressional appropriations, and in an edition of several thousand copies, thus permitting its wide distribution. The principal feature of the annual report is a general appendix containing about 30 se- lected or original memoirs illustrating the more remarkable and im- portant developments in the physical and natural sciences, as well as showing the general character of the operations of the Institution, In addition to the publications mentioned above, there are several other series of works issued under the direction of the Institution through its various branches or bureaus. These include the Annual Report, and the Proceedings and Bulletin of the National Museum; the Contributions from the National Herbarium; the Annual Report and Bulletins of the Bureau of American Ethnology; and the An- nals of the Astrophysical Observatory, all of which are Government publications, being printed through annual allotments by act of Congress. Smithsonian Contributions to Knowledge—The chief character- istic of memoirs printed in the Contributions to Knowledge is that they are records and discussions of original investigations and con- stitute important additions to knowledge. Since the establishment of this series in 1848, about 150 of these memoirs have been published in 35 quarto volumes. The most recent memoir of this series, re- viewed in my last report, was the “ Langley Memoir on Mechanical Flight,” recording the experiments of the late Secretary Langley, which resulted in his successful demonstration of the practicability of aerial navigation with machines heavier than air. Smithsonian Miscellaneous Collections—In this series 40 papers were issued, forming parts of five volumes, the titles of which are enumerated in the appendix herewith. Among these numerous papers were two articles by the secretary describing further results of his studies of Cambrian fossils, a bibliography of the geology and mineralogy of tin, and a large number of papers descriptive of results of the Smithsonian African expedition under Col. Roosevelt, the Paul J. Rainey African expedition, and the Smithsonian biologi- cal survey of the Panama Canal Zone. There were also in press at the close of the year three additional papers on Cambrian fossils, one of them, in particular, giving an account of the Mount Robson region ; and a paper, as already mentioned, by Dr. Leonard Hill and other REPORT OF THE SECRETARY. 17 . investigators of the Physical Laboratory of the London Hospital Medical College, discussing the results of experiments to determine “The influence of the atmosphere on our health and comfort in con- fined and crowded places.” The authors conclude that— No symptoms of discomfort, fatigue, or illness results, so long as the tempera- ture and moisture are kept low, from air rendered, in the chemical sense, highly impure by the presence of human beings. Such air can be borne for hours without any evidence of bodily or mental depression. * * * Heat stagna- tion is therefore the one and only cause of the discomfort, and all the symptoms arising in the so-called vitiated atmosphere of crowded rooms are dependent on heat stagnation. The moisture, stillness, and warmth of the atmosphere are responsible for all effects, and all the efforts of the heating and ventilating engineer should therefore be directed toward cooling the air in crowded places and cooling the bodies of the people by setting the air in motion by means of fans. * * * The essentials required of any good system of ventilation are, then: (1) Movement, coolness, proper degree of relative moisture of the air, and (2) reduction of the mass influence of pathogenic bacteria. The chemical purity of the air is of very minor importance and will be adequately insured by attendance to the essentials. Smithsonian Report—The completion of the annual report for 1911 was long delayed at the Government Printing Office, awaiting a supply of the quality of paper used in that publication. The general appendix of the volume contained 36 articles of the usual character. The report for 1912 was in type at the close of the fiscal year. The popularity of this work continues unabated, the entire edition each year becoming exhausted very soon after its publication. National Museum publications—The publications by the Museum during the year comprised two volumes of Proceedings, pamphlet copies of 96 articles from the Proceedings, two Bulletins, and nine parts of volumes of Contributions from the National Herbarium. An interesting work in press at the close of the year, prepared by Assistant Secretary Richard Rathbun, gives a descriptive account of the building recently erected for the departments of natural history of the United States National Museum. The book is illustrated with 34 plates and, besides a general description of the building, includes special chapters relating to structural details and mechanical equip- ment, Zoological nomenclature.—Opinions 52 to 56 rendered by the In- ternational Commission on Zoological Nomenclature were published in the usual form. The Institution also continues to aid the work of this commission by providing funds for clerical services in connec- tion with the office of its secretary in this country. Publications of the Bureau of American Ethnology.—The publica- tions issued by the Bureau of American Ethnology were the Twenty- eighth Annual Report, containing papers on Casa Grande, the antiq- uities of the upper Verde River and Walnut Creek Valleys, Ariz., 44863°—sm 1913——2 18 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. the linguistics of Algonquian tribes; also Bulletin 52 on early man in South America, and Bulletin 54 on the physiography of the Rio Grande Valley, New Mexico. The Astrophysical Observatory had completed work on volume 3 of the Annals of the Observatory at the close of the year, and it was expected that the distribution of the edition would take place soon after July 1. Reports of historical and patriotic societies —In accordance with the national charters of the American Historical Association and the National Society of the Daughters of the American Revolution, an- nual reports of those organizations were submitted to the Institution and communicated to Congress. Allotments for printing.—The allotments to the Institution and its branches, under the head of “ Public printing and binding,” during the fiscal year, aggregating $74,900, were all utilized with the ex- ception of small balances on work in progress at the close of the year. The allotments for the year ending June 30, 1914, are as follows: For the Smithsonian Institution, for printing and binding annual re- ports of the Board of Regents, with general appendixes_____________ $10, 000 For the annual reports of the National Museum, with general ap- pendixes, 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 turkey or material not more expensive, scientific books and pamphlets presented to or ac- quired by stheuNational Museum iibray22 23 es Se 37, 500 For the annual reports and bulletins of the Bureau of American Ethnology, and for miscellaneous printing and binding for the bureau_ 21, 000 For miscellaneous printing and binding: Imtermational exchanges) » | King snake (Ophibolus getulus) -___-_- “| Common garter snake (Hutenia sirta- WB) ohio eA a RTE See 1 Texas water snake (Hutenia proxvima) _ 3 | Water moccasin (Ancistrodon. piscivo- 5) TUS Wane eS eee Ee eee 1 | Copperhead (Ancistrodon contortria) __ 1 | Diamond rattlesnake (Crotalus adaman- 2 TOUS) ei oe eh eS ee 1 | Banded rattlesnake (Crotalus horri- i AUS) ee 2 Ce PURI Cee eee GIFTS. Mr. Raymond Adams, Washington, D. C., an alligator. Dr. J. S. Billupp, Leeland, Md., an American magpie. Mr. M. HB. Boyd, Washington, D. C., a horned lizard. Mr. August Busck, Washington, D. C., two marmosettes. Mr. W. M. Chrissinger, Hagerstown, Md., a black snake. Mrs. Eugenia S. Cleary, Washington, D. C., a common canary. Mr. Wallace Eyans, Oak Park, Ill., four mink. Capt. W. EH. P. French, Washington, D. C., an alligator. Mr. F. P. Hall, Washington, D. C., three alligators. Mr. Kidwell, Washington, D. C., a bald eagle. Mr. M. 8S. Lawrence, Washington, D. C., a common opossum. Mr. De Witt T. Leach, Washington, D. C., a woodchuck. Mr. Ralph W. Lee, Washington, D. C., an alligator. Miss Clare and Mr. James McCall, Mapleton, Pa., a banded rattlesnake. Mr. D. McLanahan, Washington, D. C., a barred owl. Mr. E. B. McLean, Washington, D. C., a skunk, two raccoons, and a toucan. Mr. J. W. Mills, Washington, D. C., an alligator. Mr. Victor Mindeleff, Washington, D. C., a crocodile. Mr. Thomas Moreland, Washington, D. C., a barn owl. Hon. L. P. Padgett, Columbia, Tenn., a gray coatimundi. Capt. A. W. Perry, Washington, D. C., a western mocking bird. Capt. R. B. Putnam, Washington, D. C., a gray coatimundi. Mr. fF. J. Raymond, Washington, D. C., a green parrot. Dr. C. W. Richmond, Washington, D. C., two barn owls. 44863°—sm 1913——6 81 keh es CD a 82 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. Mrs. Ricketson, Washington, D. C., a common raccoon. Mr. Richard A. Sargent, Washington, D. C., a common canary. Mrs. Gurnon P. Scott, Washington, D. C., a shell parrakeet. Mr. BE. 'T. Seton, Cos Cob, Conn., three common skunks. Mr. Ellis Spear, Washington, D. C., two common canaries. Miss Straub, Washington, D. C., a green parrot. Mr. H. EH. Thomas, Washington, D. C., a black snake. Mrs. HE. St. Clair Thompson, Washington, D. C., a common canary. Mrs. GC. V. Williams, Washington, D. C., an alligator. Hon. Woodrow Wilson, Washington, D. C., a horned lizard. The Zoological Society of Philadelphia, six muskrats. Unknown donors, a screech owl, five barn owls, an English pheasant, and an alligator. LOSSES OF ANIMALS. The most serious loss was among the ruminants. An eland, a bontebok, a Coke’s hartebeest, and a harnessed antelope died from tuberculosis; a moose and a reindeer from enteritis; two tahr goats from pneumonia; and an American bison, 21 years old, from arterio- sclerosis. A fur seal also died from enteritis and a grizzly bear that when captured, 19 years before, weighed 730 pounds was killed because of its general decrepitude. A number of birds were lost through the depredations of raccoons and other animals living at large in the park. The night herons had increased to such an extent in the flying cage that they interfered with the nesting of other birds there, and the greater part of them (114) were disposed of, a few as gifts to other zoological collections. Of animals that died in the park, 107 were transferred to the National Museum. Autopsies were made as heretofore by the Patho- logical Division of the Bureau of Animal Industry, Department of Agriculture.? STATEMENT OF THE COLLECTION. ACCESSIONS DURING THE YEAR. Bresenteders sll eet el tl ee 66 AESIGGM SGC ees ee a ee eee 162 Bornvand hatched in: National Zoological Park -_-_._ -—. ee 78 Receive in exchanges 20.20 oS i eee 18 Meposited in National Zoological Park... 4. eee 6 Capiredvin: National Zoological Park=22*_~. 20 Se 1 MRO GAN ee ee. 2 EE SE 2s pol 1The causes of death were reported to be as follows: Enteritis, 37; gastritis, 1; impaction of bowel, 3; pneumonia, 14; tuberculosis, 10; congestion of lungs, 4; asper- gillosis, 4; malignant catarrh of nose and throat, 1; inflammation of pharynx and larynx, 1; congestion of liver, 1; septicemia, 3; sarcoma, 1; abscess, 1; gangrene of thyroid gland, 1; generalized fat necrosis, 1; arteriosclerosis, 1; umbilical infection, 1; starvation (snakes), 8; killed because of arthritis, 1, and of senile debility, 1; accidents (killed by animals, etc.), 32; no cause found (only viscera examined in most cases), 12. REPORT OF THE SECRETARY. 83 SUMMARY. ENTATTTMEM ES y Latah aos fr Ba Ag USM SL ce Re Ne Le ed Se A ietsta | PPO CESSTOM SM CRU LTS He Nyaa LAURE a dd ATION ate a el SET ahs 3381 BEC tical Mpeierer eee tee ee a Et ON ad ee lot Le eee ad 1, 882 Deduct loss (by exchange, death, return of animals, ete.) _~__________ 414 RO Hee TTeV ETC TIRC SOL Dike yee eae a I ee ee 1, 468 Class. Species. inated Se ee a eee ate sce cacys oiSb oss mien soc gnee sees sess che ctese sick 154 606 Ene PEE ey Ben Sho fh oe eee ocaddiececbeuecpaes saves cecboes 202 786 eal PEE EE Pre ER SNe Seo wa bak oe wiclsatia cise da Sd sleidltties oilseed tenes 31 76 A ee Ilan ote Saloon) sw c\n wroininiain'2 = no cin = a\e\niaiao a nla = _2- eee 4, 062 MNO GAS eee ee ee 17, 565 Very respectfully, F. W. True, Assistant Secretary, in charge of Library and Fachanges. Dr. Cuartes D. Watcortt, Secretary of the Smithsonian Institution. APPENDIX 7. REPORT ON THE INTERNATIONAL CATALOGUE OF SCIENTIFIC LITERATURE. Sir: 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 year ending June 30, 1913. The International Catalogue of Scientific Literature now consists of 33 regional bureaus, anew bureau representing the Argentine Republic having been recently established at the Universidad de Buenos Aires. It appears probable that Bolivia will soon also be represented by a regional bureau. The following-named countries are represented by regional bureaus supported in most cases by direct governmental grants: Argentine Republic, Austria, Belgium, Canada, Cuba, Den- mark, Egypt, Finland, France, Germany, Greece, Holland, Hungary, India and Ceylon, Italy, Japan, Mexico, New South Wales, New Zealand, Norway, Poland, Portugal, Queensland, Russia, South Africa, South Australia, Spain, Straits Settlements, Sweden, Swit- zerland, United States of America, Victoria and Tasmania, and Western Australia. These bureaus, acting through the London Central Bureau, form the organization of the International Catalogue of Scientific Litera- ture, whose duty it is to collect, index, classify, and publish a current catalogue of the world’s scientific literature. The London Central Bureau assembles, edits, and publishes the classified references sup- plied by the regional bureaus. The enterprise was begun in 1901 and since then there have been published annually 17 volumes, one each year for the following-named branches of science: Mathematics, mechanics, physics, chemistry, astronomy, meteorology, mineralogy, geology, geography, paleon- tology, general biology, botany, zoology, anatomy, anthropology, physiology, and bacteriology. All of the first 9 annual issues of the catalogue have been pub- lished, 14 volumes of the tenth issue, and 2 volumes of the eleventh, a total of 169 regular volumes in addition to several special volumes of Schedules and Lists of Journals. The annual subscription price for a complete set of 17 volumes is $85. The receipts from the sale of the catalogue are used for the maintenance of the central bureau, which pays for editing and print- 101 102 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, ing the catalogue. The balance sheet for the ninth annual issue showed a credit for that issue of about $1,500 over and above ex- penses. This is considered a satisfactory showing in view of the fact that undertakings of this kind are in no sense commercial and can hardly be expected to meet necessary expenses without aid from an endowment or some similar source. The enterprise was begun with- out a working capital other than the sums advanced from time to time by the Royal Society of London. As interest is paid on all sums so advanced the financial showing is not what it would have been had the enterprise possessed a working capital. The sum needed to completely pay off all obligations and leave a substantial balance for the maintenance of the central bureau is only about $75,000, and it would be difficult to find an object more deserving of assistance and encouragement than this International Catalogue of Scientific Litera- ture whose purpose is to aid research and investigations in scientific fields by furnishing a current classified index to the literature of science. Some idea of the extent of the work may be gained from the fact that about two and one-half million classified citations were re- ceived by the central bureau from ,the regional bureaus since the beginning of the enterprise in 1901, of these over 290,000 were pre- pared by the regional bureau of the United States. During the year 27,995 cards were sent from this bureau to the London Central Bureau, as follows: Literature of— Ree ee ee Ee ME a 9 3s aE IN REALE a aS i NS 5 1S aie sletelnlont lala pans bist Deemed) oo 12 AEH LLC OO ROU A ie SI OE ee 14 sa ol MD MLSE CUPL MRSTURPealions MAN) Le G28 131 iC SEE CRT ONL ON FE YP eaten | YL 226 OOS ease NE Aha 324 OOO a ie aE oi bie ee 685 i (0) (i napa lilo cobydrte he i aN at Nb 3, 214 12) mal ied lars oy rn ea 6, 950 HAS LH EUAN EEA Ret TI 16, 425 REPORT OF THE SECRETARY. 103 The following table shows the number of cards sent each year as well as the number of cards representing the literature of each year from 1901 to 1912, inclusive: Literature of— | 1901 | 1902 | 1903 | 1904 | 1905 | 1906 | 1907 | 1908 | 1909 | 1910 | 1911 | 1912 fon year. Year ending June 30— 1902. EA] | al al LER rat PEE ea reli 4 PR Ih ON oh) eer WOO Meee Pr gel [> Nees 6, 990 1903H cote e roo! GalSU RR TssOl eee a eee: eee een ee [mass oun aa lomaratnle. Soe oko eect ease 14, 480 LOA ee eos 20 SPI EHIOC | META 2 Ea Pe DS a i 21, 213 ADH ees ant: G19]. 25780|TV143| (SUG4Oee wo |tos ek lse sec lsce teu ee. | plat eae eee eee 24,182 ICTR eee SyOyl|| 9: Ged OS} GRE Ns Ts MC IU Ie sae ee ee eel secor|eaacee 25, 601 TOTS eee See aeesill eo 2721 OF 0222-578 esc eens ences [eens ene sees 28, 629 190Rs soe os eee) 40 g| 4523] S66|.) 95615; 629) 72 217/13) 4a012 Tene Eee heetie Se Rae 28, 528 T9002 beeen 133/092 235|0 0373), 309) .1,656| 745 410l48- 500183 784) _ ps5]. on) sees eee ae 34, 409 LOT Osea 72| 173| 248] 465] 1,163] 1,502] 3,160] 6,305|11,994]......|......].....- 25, 082 AQUA RARE LS 3. 3, 26] 28] 218] 129] 374] 423) 1,301| 8, 836/14, 682|/......|.....- 26, 020 TRY GO. Set eg Rae ea a 4) 243] 386] 562] 1,480] 1,949] 3,372] 5, 231/13, 974)...... 27,201 1OIS ee eee oss | 9 5| 12) 14) 131] 226) 324] 685] 3,214] 6, 950/16, 425] 27,995 Motalecemsess 19, 104/22, 633]25, 312|28, 254127, 000/26, 774127, 227/28, 663/24, 887/23, 127/20, 924/16, 425] 290, 330 Control over the catalogue is vested in a body known as the Inter- national Convention which has held two meetings in London, the last being in 1910. In the intervals between the meetings of this body the administration of the catalogue is directed by the Interna- tional Council expected to meet in London once in threg years and to which each country represented by a regional bureau is requested to send a representative. Meetings of the International Council were held in 1904, 1907, and in 1909, and a meeting of the International Convention was held in 1910, so that a meeting of the International Council was planned for 1913. This meeting, by a vote of the executive committee, was postponed until 1914, as a number of new plans for the reduction of cost and increasing the efficiency of the catalogue were either just going into effect, or had been in operation but a short time, and it was felt that the later date would give the members of the council a better opportunity to judge their value. Very respectfully, Leonarp C. GUNNELL, Assistant in Charge. Dr. Cuartes D, Watcorr, Secretary of the Smithsonian Institution. APPENDIX 8. REPORT ON THE PUBLICATIONS. Sir: I have the honor to submit the following report on the publi- cations of the Smithsonian Institution and its branches during the year ending June 30, 1918: The Institution proper published during the year 40 papers in the series of “Smithsonian Miscellaneous Collections,” an annual report, and pamphlet copies of 37 papers from the general appendix of the report. The Bureau of American Ethnology published an annual report and 38 bulletins, and the United States National Mu- seum issued 96 miscellaneous papers from the Proceedings, a new bulletin, reprint editions of 2 bulletins, and 9 parts of volumes per- taining to the National Herbarium. The total number of copies of publications distributed by the Institution proper during the year was 111,283, or 1,052 more than during the previous year. This aggregate includes 600 volumes and memoirs of Smithsonian Contributions to Knowledge, 62,688 volumes and pamphlets of Smithsonian Miscellaneous Collections, 22,401 volumes and pamphlets of the Smithsonian Annual Reports, 8,787 special publications, including volume 3 of the Annals of the Astrophysical Observatory and reports on the Harriman Alaska expedition; 15,070 volumes and pamphlets of the Bureau of Ameri- ean Ethnology publications, 1,646 Annual Reports of the American Historical Association, 8 publications of the United States National Museum, and 83 publications not of the Smithsonian Institution or its branches. The National Museum distributed a total of 71,600 copies of its several publications. SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE. QUARTO. No publications of this series were issued during the year. SMITHSONIAN MISCELLANEOUS COLLECTIONS. OCTAVO. Of the Miscellaneous Collections, volume 57,-2 papers were pub- lished; of volume 58, 1 paper, and title-page and contents of the vol- ume; of volume 59, 5 papers; of volume 60, 28 papers; of volume 61, 4 papers; in all, 40 papers. These are as follows: 104 REPORT OF THE SECRETARY. 105 Volume 57. No. 9. New York Potsdam-Hoyt Fauna. By Charles D. Walcott. Published September 14, 1912. 54 p., 13 pls. (Publ. 2136.) No. 10. Group terms for lower and upper Cambrian series of formations. By Charles D. Walcott. September 16,1912. 3p. (Publ. 2137.) Volume 58. No. 2. Bibliography of the geology and mineralogy of tin. By Frank L. and Eva Hess. July 29, 1912. v, 408 p. (Publ. 1987.) Title-pages and contents. December 31, 1912. vp. (Publ. 2160.) Volume 59. No. 11. Expeditions organized and participated in by the Smithsonian Institu- HOnIn 910) and AOL Duly 17, 1912:, 51 p:, 1 pl. -56ones,, (eubik: 2087.) No. 16. New Rodents from British East Africa. By Edmund Heller. July 5, 1912. 20 p. (Publ. 2094.) No.17. New Diptera from Panama. By J. R. Malloch. July 18, 1912. 8 p. (Publ. 21383.) No. 18. New species of landshells from Panama Canal Zone. By William H. Dall. July 27, 1912. 3p.,2 pls. (Publ. 2134.) No. 20. The recognition of Pleistocene faunas. By Oliver P. Hay. August 17, Ola Gsp;,,10 figs, (Publ: 2139:) Volume 60. No. 1. Three new species of Pipunculide (Diptera) from Panama. By J. R. Malloch. September 6, 1912. 4 p., 3 figs. (Publ. 2141.) No. 2. New mammals from eastern Panama. By E. A. Goldman. September 20, 1912. 18 p. (Publ. 2142.) No. 8. Descriptions of new genera, species, and subspecies of birds from Pan- ama, Colombia, and Ecuador. By E. W. Nelson. September 27, 1912. 25 p. (Publ. 2148.) No. 4. Rubelzul cotton: A new species of Gossypium from Guatemala. By Fred- erick L. Lewton. October 21,1912. 2 p.,2 pls. (Publ. 2144.) No. 5. Kokia: A new genus of Hawaiian trees. By Frederick L. Lewton. October 22, 1912. 4p.,5 pls. (Publ. 2145.) No. 6. The cotton of the Hopi Indians: A new species of Gossypium. By Fred- erick L. Lewton. October 23, 1912. 10 p., 5 pls. (Publ. 2146.) No. 7. Descriptions of one hundred and four new species and subspecies of birds from the Barussan Islands and Sumatra. By Harry C. Oberholser. October 26, 1912. 22 p. (Publ. 2147.) No. 8. New genera and races of African ungulates. By Edmund Heller. No- vember 2, 1912. 16 p. (Publ. 2148.) No. 9. A recent meteorite fall near Holbrook, Navajo County, Arizona. By George P. Merrill. November 21, 1912. 4 p. (Publ. 2149.) No. 10. The crinoids of the Natural History Musuem at Hamburg. By Austin Hobart Clark. November 7, 1912. 33 p. (Publ. 2150.) No. 11. A fossil toothed cetacean from California, representing a new genus and species. By Frederick W. True. November 1, 1912. 7 p., 2 pls. (Publ. 2151.) No. 12. New races of insectivores, bats, and lemurs from British Hast Africa. By Edmund Heller. November 4, 1912. 18 p. (Publ. 2152.) 106 No. 18. No. 14. No. 15. No. 26. ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. A study of the salinity of the surface water in the North Pacific Ocean and the adjacent enclosed seas. By Austin Hobart Clark. December 4, 1912. 338 p. (Publ. 2153.) New mammals from the highlands of Siberia. By N. Hollister. No- vember 29, 1912. 6p. (Publ. 2157.) A new subspecies of crossbill from Newfoundland. By A. C. Bent, December 12, 1912. 3p. (Publ. 2158.) . Remains in Eastern Asia of the race that peopled America. By Ales Hrdli¢ka. December 31, 1912. 5 p., 3 pls. (Publ. 2159.) . Notes on American species of Peripatus, with a list of known forms. By Austin Hobart Clark. January 25, 1918. 5p. (Publ. 2163.) . Smithsonian pyrheliometry revised. By C. G. Abbot and L. B. Aldrich. February 1, 1913. 7 p. (Publ. 2164.) 9. Description of a new gazelle from northwestern Mongolia. By N. Hol- lister. February 8, 19138. 2p. (Publ. 2165.) . Description of a new African grass-warbler of the genus Cisticola. By Edgar A. Mearns. February 14, 1918. 2 p. (Publ. 2166.) . Two new subspecies of birds from the slopes of Mount Pirri, eastern Panama. By HE. W. Nelson. February 26, 1918. 2 p. (Publ. 2167.) . Descriptions of new mammals from Panama and Mexico. By EH. A. Goldman. February 28, 1913. 20 p. (Publ. 2168.) . Two new mammals from the Siberian Altai. By N. Hollister. March 18, 1913. 3 p. (Publ. 2171.) . Diagnosis of a new beaked whale of the genus Mesoplodon from the coast of North Carolina. By Frederick W. True. March 14, 1913. 2pea (Publy 21'72:) ’ Notice of the occurrence of a Pleistocene camel north of the Arctie Circle. By James Williams Gidley. March 21, 1918. 2 p. (Publ. 2173.) . An extinct American eland. By James Williams Gidley. March 22, 1915.) 3) p:,.4, pl... (Publ. 2174.) . A new vole from eastern Mongolia. By Gerrit S. Miller, jr. March 31, 1913 e2epe tpl (Publis 2u75:) . Voleanoes and climate. By C. G. Abbot and F. E. Fowle. March 28, 1913. 24 p., 3 figs. (Publ. 2176.) Volume 61. Description of the skull of an extinct horse, found in central Alaska. By Oliver P. Hay. June 4, 1913. 18 p., 2 pls. (Publ. 2181.) Report on fresh-water Copepoda from Panama, with descriptions of new species. By C. Dwight Marsh. June 20, 1913. 30 p., 5 pls. (Publ. 2182.) Saffordia, a new genus of ferns from Peru. By William R. Maxon. May 26, 1913. 5 p., 2 pls., 1 fig. (Publ. 2183.) . A new dinosaur from the lance formation of Wyoming. By Charles W. Gilmore. May 24, 1913. 5 p., 5 figs. (Publ. 2184.) The following papers of the Smithsonian Miscellaneous Collec- tions were in press at the close of the fiscal year: No. 11. Volume 57. Cambrian geology and paleontology. II. New Lower Cambrian subfauna. By Charles D. Walcott. 309-326 p., 50-54 pls. (Publ. 2185.) REPORT OF THE SECRETARY. 107 No. 12. Cambrian geology and paleontology. II. Cambrian formations of the Robson Peak district, British Columbia and Alberta, Canada. By Charles D. Walcott. 3827-348 p., 55-59 pls. (Publ. 2186.) No. 138. Cambrian geology and paleontology. II. Dikelocephalus and other gen- era of the Dikelocephalinse. By Charles D. Walcott. 345-408 p., 60— 70 pls. (Publ. 2187.) Volume 59. No. 19. Early Norse Visits to North America. By William H. Babcock. iii, 213 p., 10 pls. (Publ. 21388.) Volume 60. No. 23. The influence of the atmosphere on our health and comfort in confined and crowded places. By Leonard Hill, Martin Flack, James Me- Intosh, R. A. Rowlands, and H. B. Walker. Hodgkins Fund. 96 p. (Publ. 2170.) No. 30. Explorations and field-work of the Smithsonian Institution in 1912. 76 p., 82 figs. (Hnd of volume.) (Publ. 2178.) Volume 61. No. 1. The White Rhinoceros. By Edmund Heller. 77 p., 31 pls. (Publ. 2180. ) SMITHSONIAN ANNUAL REPORTS. Report for 1911. The Annual Report of the Board of Regents for 1911 was received from the Public Printer in completed form in January, 1913. Annual Report of the Board of Regents of the Smithsonian Institution, show- ing operations, expenditures, and conditions of the Institution for the year ending June 30, 1911. xii, 688 p., 97 pls. (Publ. 2095.) Small editions of the following papers, forming the general ap- pendix of the annual report for 1911, were issued in pamphlet form: The gyrostatic compass. By H. Marchand. 5p., 3 pl. (Publ. 2096.) Radiotelegraphy. By G. Marconi. 15 p.,1 pl. (Publ. 2097.) Multiplex telephony and telegraphy by means of electric waves guided by wires. By George O. Squier. 21 p.,1 pl. (Publ. 2098.) Recent experiments with invisible light. By R. W. Wood. 12 p., 6 pls. (Publ. 2099. ) What electrochemistry is accomplishing. By Joseph W. Richards. 16 p. (Publ. 2100.) Ancient and modern views regarding the chemical elements. By William Ramsay. 15 p. (Publ. 2101.) The fundamental properties of the elements. By Theodore William Richards. Avp. (Publ. 2102.) The production and identification of artificial precious stones. By Noel Heaton. 18 p., 3 pls. (Publ. 2103.) The sterilization of drinking water by ultra-violet radiations. By Jules Cour- mont. 11 p. (Publ. 2104.) The legal time in various countries. By M. Philippot. 8 p. Map. (Publ. 2105. ) 108 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, Some recent interesting developments in astronomy. By J. S. Plaskett. 16 p. (Publ. 2106.) The age of the earth. By J. Joly. 23 p. (Publ. 2107.) . International air map and aeronautical marks. By Ch. Lallemand. 8p. (Publ. 2108. ) : Geologic work of ants in tropical America. By J. C. Branner, 31 p., 1 pl. (Publ, 2109.) On the value of the fossil floras of the arctic regions as evidence of geological climates. By A. G. Nathorst. 10 p. (Publ. 2110.) Recent advances in our knowledge of the production of light by living organ- isms. By F. Alex. McDermott. 18 p. (Publ. 2111.) Organie evolution; Darwinian and de Vriesian. By N. C. Macnamara. 16 Da (eublss 225) Magnalia nature; or the greater problems of biology. By D’Arey Wentworth Thompson. 15 p. (Publ, 2113.) A history of certain great horned owls. By Charles R. Keyes. 11 p, 8 pls. (Publ. 2114.) The passenger pigeon. By Pehr Kalm (1759) and John James Audubon (1831). US jek IT Gea oil ab lsy)) Note on the iridescent colors of birds and insects. By A. Mallock. 8 p., 3 pls. (Publ. 2116.) On the positions assumed by birds in flight. By Bentley Beetham, 7 p., 8 pls. (Publ. 2117.) ; The garden of serpents, Butantan, Brazil. By S. Pozzi. 6 p. (Publ. 2118.) Some useful native plants from New Mexico. By Paul C. Standley. 16 p., 13 pls. (Publ. 2119.) The tree ferns of North America. By William R. Maxon. 29 p.,15 pls. (Publ. 2120.) The value of ancient Mexican manuscripts in the study of the general develop- ment of writing. By Alfred M. Tozzer. 14 p.,5 pls. (Publ. 2121.) The discoverers of the art of iron manufacture. By W. Belck. 15 p. (Publ. 2122. The Kabyles of north Africa. By A. Lissauer. 16 p., 12 pls. (Publ. 2128.) Chinese architecture and its relation to Chinese culture. By Ernst Boersch- mann. 29p.,10 pls. (Publ. 2124.) The Lolos of Kientchang, western China By A. F. Legendre. 18 p., 4 pls. (Publ. 2125.) The physiology of sleep. By R. Legendre. 16 p. (Publ. 2126.) Profitable and fruitless lines of endeavor in public health work. By Edwin O. Jordan. 8p. (Publ. 2127.) Factory sanitation and efficiency. By C.-K. A. Winslow. 6p. (Publ. 2128.) The physiological influence of ozone. By Leonard Hill and Martin Flack. 12 p. (Publ. 2129.) Traveling at high speeds on the surface of the earth and above it. By H. S. Hele-Shaw. 21 p. (Publ. 21380.) Robert Koch, 1843-1910. By C. J. M. Sp.,1pl. (Publ. 2181.) Sir Joseph Dalton Hooker, 1817-1911. By Lieut. Col. D. Prain. 18 p., 1 pl. (Publ. 2182.) Report for 1912. The report of the executive committee and proceedings of the Board of Regents of the Institution, as well as the report of the Secretary for the fiscal year ending June 30, 1912, both forming part REPORT OF THE SECRETARY. 109 of the annual report of the Board of Regents to Congress, were pub- lished in pamphlet form in December, 1912, as follows: Report of the executive committee and Proceedings of the Board of Regents for the year ending June 30, 1912. 22 pp. (Publ. 2155.) Report of the secretary of the Smithsonian Institution for the year ending June 30, 1912. iii, 110 p., 2 pl. (Publ. 2156.) The general appendix to the Smithsonian Report for 1912 was in type, but actual presswork was not completed at the close of the fiscal year. In the general appendix are the following papers: The year’s progress in astronomy, by P. Puiseux. The spiral nebule, by P. Puiseux. The radiation of the sun, by C. G. Abbot. Molecular theories and mathematics, by Emile Borel. Modern mathematical research, by G. A. Miller. The connection between the ether and matter, by Henri Poincaré. Experiments with soap bubbles, by C. V. Boys. Measurements of infinitestimal quantities of substances, by William Ramsay. The latest achievements and problems of the chemical industry, by Carl Duisberg. Holes in the air, by W. J. Humphreys. Review of applied mechanics, by L. Lecornu. Report on the recent great eruption of the voleano ‘‘ Stromboli,” by Frank A. Perret. The glacial and postglacial lakes of the Great Lakes region, by Frank B. Taylor. Applied geology, by Alfred H. Brooks. The relations of paleobotany to geology, by F. H. Knowlton. Geophysical research, by Arthur L. Day. A trip to Madagascar, the country of beryls, by A. Lacroix. The fluctuating climate of North America, by Ellsworth Huntington. The survival of organs and the “ culture” of living tissues, by R. Legendre. Adaptation and inheritance in the light of modern experimental investigation, by Paul Kammerer. The paleogeographical relations of antarctica, by Charles Hedley. The ants and their guests, by P. E. Wasmann. The penguins of the antarctic regions, by L. Gain. The derivation of the European domestic animals, by C. Keller. Life: its nature, origin, and maintenance, by EH. A. Schifer. The origin of life: a chemist’s fantasy, by H. E. Armstrong. The appearance of life on worlds and the hypothesis of Arrhénius, by Alphonse Berget. The evolution of man, by G. Elliot Smith. The history and varieties of human speech, by Edward Sapir. Ancient Greece and its slave population, by S. Zaborowski. Origin and evolution of the blond Europeans, by Adolphe Bloch. History of the finger-print system, by Berthold Laufer. Urbanism: A historic, geographic, and economic study, by Pierre Clerget. The Sinai problem, by E. Oberhummer. The music of primitive peoples and the beginnings of Huropean music, by Willy Pastor. Expedition to the South Pole, by Roald Amundsen. Icebergs and their location in navigation, by Howard T. Barnes. Henri Poincaré, his scientific work, his philosophy, by Charles Nordmann, 110 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. SPECIAL PUBLICATIONS. The following special publications were issued in octavo form: Publication lists. Classified list of Smithsonian publications available for distribution January 1, 1913. Published February 25, 1913. vi, 31 p. (Publ. 2161.) Publications of the Smithsonian Institution issued between January 1 and July 1, 1912, July 19,1912: 2) p. (Publ. 2135.) Publications of the Smithsonian Institution issued between January 1 and October 1, 1912. October 28, 1912. 3p. (Publ. 2154.) Publications of the Smithsonian Institution issued between January 1 and December 31, 1912. February 1, 1918. 5 p. (Publ. 2162.) Publications of the Smithsonian Institution issued between January 1 and Mareh 31, 1918. April 10, 19138. 1p. (Publ. 2179.) Zoological nomenclature. Opinions rendered by the International Commission on Zoological Nomencla- ture, Opinions 52-56. May 10, 1918. 12 p. (Publ. 2169.) The following special publication was in press at the. close of the fiscal year: Harriman Alaska series. Vol. 14. Monograph of Shallow-water Starfishes of the North Pacific Coast from the Arctic Ocean to California. By Addison Emery Verrill. xii, 338 p., 110 pl. (Publ. 2140.) PUBLICATIONS OF THE UNITED STATES NATIONAL MUSEUM. The publications of the National Museum are: (a) The annual report to Congress; (0) the proceedings of the United States Na- tional 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. The publications issued by the National Museum during the year comprised 96 papers of the Proceedings, 2 bulletins, and 9 parts of Contributions from the National Herbarium. The issues of Proceedings were as follows: Vol. 42, papers 1907 to 1922, inclusive; Vol. 43, papers 1923 to 1945, inclusive; Vol. 44, papers 1946 to 1975, inclusive; Vol. 45, papers 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2008, and 2004; a total of 96 papers. The bulletins were as follows: Bulletin 79. List of North American Land Mammals in the United States Na- tional Museum, 1911. By Gerrit S. Miller, jr. Bulletin 81. Synopsis of the Rotatoria. By Harry K. Harring. In the series of Contributions from the National Herbarium (oc- tavo) there appeared: REPORT OF THE SECRETARY. Last Volume 16. Part 3. The North American species of Nymphaea. By Gerrit S. Miller, jr., and Paul C. Standley. Part 4. Descriptions of new plants preliminary to a report upon the flora of New Mexico. By E. O. Wooton and Paul C. Standley. Part 5. Miscellaneous Papers. By C. V. Piper, J. N. Rose, Paul C. Standley, W. E. Safford, and E. S. Steele. Part 6. Three new genera of stilt palms (Iriarteacee) from Colombia, with a synoptical review of the family. By O. F. Cook and C. B. Doyle. Part 7. Studies in Cactacee. Part 1. By N. L. Britton and J. N. Rose. Part 8. Relationships of the false date palm of the Florida Keys, with a synop- tical key to the families of American palms. By O. F. Cook. Part 9. The genus Epiphyllum and its allies. By N. L. Britton and J. N. Rose. Volume 17. Part 1. The lichen flora of southern California. By Hermann Edward Hasse. Part 2. Studies of tropical American ferns. No. 4. By William R. Maxon. There was also reprinted an edition of 500 copies of Bulletin 71, Part 2, A monograph of the Foraminifera of the North Pacific Ocean. Part II. Textulariide, by Joseph A. Cushman; and an edition of 100 reprints of Bulletin 79, List of North American Land Mammals in the United States National Museum, 1911, by Gerrit S. Miller, jr. Among the National Museum publications in press at the close of the year were: Bulletin 80, A descriptive account of the building re- cently erected for the departments of natural history of the United States National Museum, by Richard Rathbun. 131 p., 34 pl, and the annual report for 1912. PUBLICATIONS OF THE BUREAU OF AMERICAN ETHNOLOGY. The publications of the bureau are discussed elsewhere in the Sec- retary’s report. The editorial work is in the charge of Mr. J. G. Gurley. One annual report and two new bulletins, together with a partially revised edition of a third bulletin, were issued during the year, as follows: Twenty-eighth Annual Report, containing (“Accompanying Papers,” as follows: (1) Casa Grande, by Jesse Walter Fewkes; (2) Antiquities of the Upper Verde River and Walnut Creek Valleys, Arizona, by Jesse Walter Fewkes; (3) Preliminary Report on the Linguistic Classification of Algonquian Tribes, by Truman Michelson.) Bulletin 30. Handbook of American Indians North of Mexico, edited by Fred- erick Webb Hodge. [By concurrent resolution of Congress in August, 1912, a reprint of this bulletin was ordered in an edition of 6,500 copies, of which 4,000 were for the use of the House of Representatives, 2,000 for the use of the Senate, and 500 for the use of the bureau. This reprint, in which were incorporated such desirable alterations as could be conveniently made with- out affecting the pagination of the work, was issued in January, 1913.] 112 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. Bulletin 52. Early Man in South America. By AleS Hrdlitka in collaboration with William H. Holmes, Bailey Willis, Fred. Eugene Wright, and Clarence N. Fenner. Bulletin 54. The Physiography of the Rio Grande Valley, New Mewico, in Re- lation to Pueblo Culture. By Edgar Lee Hewett, Junius Henderson, and Wil- fred William Robbins. The Twenty-ninth Annual Report (“Accompanying Paper,” The Ethnogeography of the Tewa Indians, by John Peabody Harrington) was in press at the close of the year. * PUBLICATIONS OF THE SMITHSONIAN ASTROPHYSICAL OBSERVA- TORY. Volume III of the Annals of the Smithsonian Astrophysical Ob- servatory was printed and nearly ready for distribution at the close of the fiscal year. PUBLICATIONS 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. The annual report for 1910 was published October 22, 1912, with contents as follows: Report of the proceedings of the twenty-sixth annual meeting of the American Historical Association. By Waldo G. Leland, secretary. Report of the proceedings of the seventh annual meeting of the Pacific coast branch. By Jacob N. Bowman, secretary of the branch. The efforts of the Danish Kings to secure the English crown after the death of Harthacnut. By Laurence M. Larson. The records of the privy seal. By James F. Baldwin. Royal purveyance in fourteenth-century England in the light of Simon Islip’s Speculum Regis. By Chalfant Robinson. Anglo-Dutch relations, 1654-1660. By Ralph C. H. Catterall. Some critical notes on the works of 8. R. Gardiner. By Roland G. Usher. The Mexican policy of southern leaders under Buchanan’s administration. By James Morton Callahan. The decision of the Ohio Valley. By Carl Russell Fish. North Carolina on the eve of secession. By William K. Boyd. The inception of the Montgomery convention. By Armand J. Gerson. The attitude of Congress toward the Pacific Railway, 1856-1862. By Allen Marshall Kline. The work of the Western State Historical Society, as illustrated by Nevada. By Jeanne E. Wier. Proceedings of the seventh annual conference of historical societies, The study of history in secondary schools. Report of the Committee of Five. Hleventh annual report of the public archives commission. By Herman Y. Ames, chairman. Appendix A. Proceedings of the second annual conference of archivists. Appendix B. Report on the archives of the State of Indiana. By Harlow Lindley. | ) REPORT OF THE SECRETARY. 118 Appendix C. Report on the archives of the State of Kentucky. By Irene T. Myers. Appendix D. Report on the archives of the State of Nebraska. By Addison E. Sheldon. Appendix EH, Notes on the archives of the Philippines. By James A. Robertson. Writings on American History, 1910. By Grace G. Griffin. The report for 1911, in two volumes, was sent to the printer on January 9, 1913, and at the close of the year was nearly ready for distribution. The contents are as follows: Volume I. Report of the proceedings of the twenty-seventh annual meeting of the American Historical Association. By Waldo G. Leland, secretary. Report of the proceedings of the eighth annual meeting of the Pacific coast branch. By H. W. Edwards, secretary of the branch. The archives of the Venetian Republic. By Theodore F. Jones. Materials for the history of Germany in the sixteenth and seventeenth cen- turies. By Sidney B. Fay. The materials for the study of the English cabinet in the eighteenth century. By Edward Raymond Turner. Francois de Guise and the taking of Calais. By Paul van Dyke. Factions in the Hnglish privy council under Elizabeth. By Conyers Read. Anglo-Dutch relations, 1671-1672. By Edwin W. Pahlow. American-Japanese intercourse prior to the advent of Perry. By Inazo Nitobe. Colonial society in America. By Bernard Moses. French diplomacy and American politics, 1794-1795. By James Alton James. The insurgents of 1811. By D. R. Anderson. The tariff and the public lands from 1828 to 1838. By Raynor G. Wellington. The “Bargain of 1844” as the origin of the Wilmot proviso. By Clark H. Persinger. Monroe and the early Mexican revolutionary agents. By Isaac Joslin Cox. Public opinion in Texas preceding the Revolution. By Hugene C. Barker. Relations of America with Spanish America, 1720-1744. By H. W. V. Tem- perley. The genesis of the Confederation of Canada. By Cephas D. Allin. Proceedings of the eighth annual conference of historical societies. List of European historical societies. Twelfth report of the public archives commission. By Herman V. Ames, chair- man. Appendix A. Proceedings of the third annual conference of archivists. Appendix B. Report on the archives of the State of Colorado. By James F. Willard. Appendix C. List of commissions and instructions to governors and lieuten- ant governors of American and West Indian Colonies, 1609-1784. Writings on American history, 1911. By Grace G. Griffin. Volume ITI. Ninth report of the historical manuscripts commission: Correspondence of Alexander Stephens, Howell Cobb, and Robert Toombs. 44863°—sM 1913-8 114 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. PUBLICATIONS OF THE SOCIETY OF THE DAUGHTERS OF THE AMERICAN REVOLUTION. The manuscript of the Fifteenth Annual Report of the National Society of the Daughters of the American Revolution for the year ending October 11, 1912, was communicated to Congress March 19, 1913. THE SMITHSONIAN ADVISORY COMMITTEE ON PRINTING AND PUBLICATION. The editor has continued to serve as secretary of the Smithsonian advisory committee on printing and publication. To this committee have been referred the manuscripts proposed for publication by the various branches of the Institution, as well as those offered for print- ing in the Smithsonian publications. The committee also considered forms of routine, blanks, and various matters pertaining to printing and publication, including the qualities of paper suitable for text and plates. Twenty-two meetings were held and 138 manuscripts were acted upon. Respectfully submitted. A. Howarp Crarn, Hditor. Dr. Cuartes D. Watcort, Secretary of the Smithsonian Institution. Bitte, Se ee APPENDIX 9. HODGKINS FUND. ADVISORY COMMITTEE ON THE LANGLEY AERO- DYNAMICAL LABORATORY. OFFICIAL STATUS. Authorization —On May 1, 1918, the Regents of the Smithsonian Institution, approving a general scheme submitted by Secretary Walcott, authorized the secretary, with the approval of the executive committee, to reopen the Langley Aerodynamical Laboratory; to appoint an advisory committee; to add, as means are provided, other laboratories and agencies; to group them into a bureau organization ; and to secure the cooperation with them of the Government and. other agencies. Functions.—The committee is to advise as to the organization and work of the Langley Aerodynamical Laboratory and of the bureau organization when adopted, and the coordination of their activities with the kindred labors of other establishments, governmental and private; it is to plan for such theoretical and experimental investiga- tions, tests, and reports as may serve to increase the safety and effectiveness of aerial locomotion for the purposes of commerce, national defense, and the welfare of man. But neither the com- mittee nor the Smithsonian Institution will promote patented devices, furnish capital to inventors, or manufacture commercially, or give regular courses of instruction for aeronautical pilots or engineers. The organization, under regulations to be established and fees to ° be fixed by the secretary, approved by the Smithsonian executive committee, may exercise its functions for the military and civil de- partments of the Government of the United States, and also for any individual, firm, association, or corporation within the United States; provided, however, that such department, individual, firm, associa- tion, or corporation shall defray the cost of all material used and of all services of persons employed in the exercise of such functions. With the approval of the Secretary of the Institution, the com- mittee is to collect aeronautical information, such part of the same as may be valuable to the Government, or the public, to be issued in bulletins and other publications. 1 Reprinted from Smithsonian Miscellaneous Collections, vel. 62, No. 1, 1913. 115 116 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. Se > ae Membership and Privileges—The advisory committee is to be composed of the director of the Langley Aerodynamical Laboratory, — when appointed, and one member to be designated by the Secretary — of War, one by the Secretary of the Navy, one by the Secretary of — Agriculture, and one by the Secretary of Commerce, together with such other persons, to be designated by the Secretary of the Smith- sonian Institution, as may be acquainted with the needs of aeronau- — tics, the total membership of such committee not to exceed 14. The members of the advisory committee, as such, are to serve without compensation, but will have refunded the necessary expenses incurred by them in going to Washington to attend the meetings of the committee and returning therefrom, and while attending the meetings. Approval of the President—On May 9, 1913, the President of the United States, by request of the Secretary of the Smithsonian Insti- tution, approved the designation of representatives of the above- named departments to serve on the advisory committee. ORGANIZATION. Officers.—The advisory committee, as constituted at its organiza- tion meeting, convened by Secretary Walcott at the Smithsonian Institution, May 28, 1913, comprises a chairman, a recorder, and 12 additional members, all of whom are to serve for one year. The officers are to be elected annually on or about May 6, and the mem- bers for the ensuing year are to be appointed prior to the date of such election. The chairman. has general supervision of the work of the advisory committee, presides at its meetings, receives the reports of the sub- committees, and makes an annual report to the Secretary of the Smithsonian Institution. Said report must include an account of _the work done for any department of the Government, individual, firm, association, or corporation, and the amounts paid by them to defray the cost of material and services, as hereinbefore mentioned. The recorder keeps the minutes of the meetings of the committee and assists the chairman in conducting correspondence and preparing reports pertaining to the business of the committee. Subcommittees.—The chairman, with the approval of the advisory — committee, may appoint standing and special subcommittees to per] form such functions as may be assigned to them. The standing subcommittees may have assigned to them investiga- tions and tests of a permanent character, which they may prosecute — { } ; from year to year and on which they are to make quarterly reports — to the chairman, followed by an annual report. Each subcommittee comprises a chairman, who must be a member of the advisory com- mittee, and others, chosen by him from that committee or elsewhere. } » i 4 4 REPORT OF THE SECRETARY. TL AGENCIES, RESOURCES, AND FACILITIES. Smithsonian Institution—The advisory committee has been pro- vided by the Smithsonian Institution with suitable office headquarters, an administrative and accounting system, library and publication facilities, lecture and assembly rooms, and museum space for aero- nautic models. The Langley Aerodynamical Laboratory has an income provided for it not to exceed $10,000 the first year (of which $5,000 has been allotted), and $5,000 annually for five years. United States Bureau of Standards.—For the exact determina- tion of aerophysical constants, the calibration of instruments, the testing of aeronautic engines, propellers, and materials of construc- tion, the committee has the cooperation of the United States Bureau of Standards, from which the Secretary of Commerce has designated one representative. This bureau has a complete equipment for studying the mechanics of materials and structural forms used in air-craft; for standard- izing the physical instruments—thermometers, barographs, pressure gauges, etc.—used in air navigation; and for testing the power, efficiency, etc., of aeronautical motors in a current of air representing the natural conditions of flight. In these general branches the technical staff of the bureau is pre- pared to undertake such theoretical and experimental investigations as may come before the advisory committee on behalf of either the Government or private individuals or organizations. United States Weather Bureau.—For studies of and reports on every phase of aeronautic meteorology, besides the usual forecasting, the committee has the cooperation of the United States Weather Bureau, from which the Secretary of Agriculture has designated one representative. This bureau has an extensive library of works on or allied to aeronautics, an instrument division for every type of apparatus for studying the state of the atmosphere, a whirling table of 30-foot radius for standardizing anemometers, a complete kite equipment with power reel, and a sounding balloon equipment with electrolytic hydrogen plant, all of which are available for scientific investigations. For special forecasts, anticipating field tests or cross-country voyages, the general service of the bureau may be called upon. War and Navy Departments.—These departments, while especially interested in aeronautics for national defense, can be of service in advancing the general science. Each has an aeronautical library; each has an official representative in foreign countries who reports periodically on every important phase of the art, whether civil or military; each has an assignment of officers who design, test, and operate air craft, and who determine largely the scope and character 118 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. of their development; each has its aeronautic station equipped with machines in actual service throughout the year. Besides various aviation establishments, the War Department has a balloon plant at Fort Myer, Va., and at Omaha, Nebr.; the Navy has its marine model basin, useful for special experiments in aeronautics, its extensive shops at the Washington Navy Yard, available for the alteration or repair of air craft or the manufacture of improved military types, and at Fort Myer three lofty open-work steel towers suitable for studies in meteorology or aerodynamics in the natural wind. Further- more, the Navy Department has detailed an officer for special re- search in aeronautics at one of the principal engineering schools. Because of their fundamental interest in aeronautics, each of these departments has two representatives on the advisory committee, and each will be able to place at the service of the committee one or more skilled aviators and aeroplanes for systematic experimentation. PRESENT NEEDS. In presenting the needs of the organization, it is well to remark that the Smithsonian Institution possesses the unique character of being a private organization having governmental functions and prerogatives. It can receive appropriations directly from Congress; it can be the recipient or the custodian of private funds for the in- crease and diffusion of knowledge; it can deposit such private funds with the United States Treasury, or place them otherwise, as may be required by the donor. Likewise, it can be the recipient or custodian of material objects representing any province of nature or any branch of human knowledge or art. This unique character allows the public to anticipate or supplement the cooperation of Congress in promoting the aerodromical (aeronautical ) work of the Tasticanees Endowment funds.—Persons approving the purpose of the organi- zation and desiring its continuity and permanence can not do better than to provide for it a steady income, either for general or for specific use. Individual endowment funds bearing the name of the giver or other person, and presented to the Smithsonian Institution, or placed in its custody at the disposal of the committee, may be recommended; also collective funds bearing the name of a society, organization, or section of the country, whether in the interest of scientific progress or of national defense. Temporary funds.—F or the prompt achievement of definite results, funds may well be offered for immediate application, both of prin- cipal and interest; as, for example, for the erection of laboratories or other buildings; for the purchase of experimental air craft, or appa- ratus, instruments, etc. Most needed is an expansion of the Langley Aerodynamical Labo- ratory providing a large and a small wind tunnel, ampler shops, and . a. ee REPORT OF THE SECRETARY. 119 instrument and model rooms. Adjacent to this, or forming a part of it, may well be the headquarters of the committee, with the col- lections of aeronautic publications and exhibits, and with designing rooms where plans for air craft may be matured by fabricators in consultation with the technical staff. This new building, if placed on the Smithsonian grounds, should be of good architecture and cost not less than $100,000. Of immediate importance is an air-craft field laboratory, adjacent to ample flying space of land and water, and adapted to assembling, adjusting, and repairing several full-scale land and water aeroplanes, and subjecting them to indoor tests and measurements, as of stress, strain, factor of safety, center of gravity, moment of inertia, work- ing condition, etc. One such plant suitably located would serve all governmental and civilian requirements for the present. A suitable site is the public land in Potomac Park in the vicinity of the Smith- sonian Institution. Here might be held air-craft competitions under the auspices of the Government. Prizes and awards—As a stimulus to the highest aeronautic achievement, or as an honorable recognition thereof, suitable prizes or awards might advantageously be offered. Provision should be made for liberal cash prizes for competitive tests of motors, pro- pellers, etc., in a purely scientific way not trenching upon the prov- ince of aero clubs. Fellowships—¥ or the prosecution of special aeronautic investiga- tions in cooperation with the advisory committee, educational insti- tutions and scientific or engineering organizations should be pro- vided with research fellowships whose incumbents may have the counsel of the committee and the advantage of its equipments. Until adequate appropriations have been made by the Government the activities of the organization and committee will have to be sustained largely by private resources. "1 rari9- teh shat a, Ae % re Biase! ae eat ne Membr iw ahi ude qile Gan cedttied tecue! Re aee yee i ee ae! EAE aegis DU cathe RST SABO haw pyasd er ae ahi 8 ut ae Medes saeco | Rak aay «ats FE Lin PORES phage Le Bh oe ee ras. (yeieol oe iihudttne Set aly Be Sgt) Miseous ad Ant das ratte sth Mee j gem te WL oi icp. oA teat Bai (geste hidhs han Tied es. yea! 7 oes esi f y r : xeu8 ) 5 wlte toon : m (ie tg oath i Beale | ij ita te + yun a, ash) a8 riGihice® HI oe bee! SP edie ; , ale iy figivn) i t) eihikwpeeyee viritos YROSEN NE ek eek ES ie aL Uy CHPeoe! ri y Mtl tay ae ink ee) ae te yea he salir e Ghd, Wie OOF Bn) @ AI 39 P “y ¥ tf Ay pi Bool bree oh . ae me: Sapte Oe he ea reacts {ou i ENteeete oY ae sFah git Hip: di a ates kcal hi 3 lee e REPORT OF THE EXECUTIVE COMMITTEE OF THE BOARD OF REGENTS OF THE SMITHSONIAN INSTITUTION FOR THE YEAR ENDING JUNE 30, 1918. 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 Institution, and a statement of the appropriations by Congress for the National Museum, the International Exchanges, the Bureau of American Ethnology, the National Zoological Park, the Astrophysi- cal Observatory, and the International Catalogue of Scientific Literature for the year ending June 30, 1918, together with balances of previous appropriations: SMITHSONIAN INSTITUTION. Condition of the fund July 1, 1913. The permanent fund of the Institution and the sources from which it has been derived are as follows: DEPOSITED IN THE TREASURY OF THE UNITED STATES. eMieStmOnStANPMSOM: o4Gl20 22 $515, 169. 00 Pesimiiynesicy.of smithson, 1867_--...-_---.---_-_- $2 a 26, 210. 63 DEpoOxineromosayines Of Income, 1867_-...____. -. 108, 620. 37 Bemiestvoraaimes: Hamilton, 18752. -._ $1, 000. 00 Accumulated interest on Hamilton fund, 1895__________ 1, 000. 00 ——_—__—_——. 2, 000. 00 Benmeraousimeon label, 1880 2 2 ee 500. 00 Deposits from proceeds of sale of bonds, 1881____________________ 51, 500. 00 SaennomasG) Hodgkins, 189122. 8 200, 000. 00 Part of residuary legacy of Thomas G. Hodgkins, 1894_____________ 8, 000. 00 epost trom savings of income, 19038. - {ee ee 25, 000. 00 Residuary legacy of Thomas G. Hodgkins, 1907____________-_----- 7, 918. 69 Weposit tromysavings of-income, 1913.2 ~~~. 636. 94 Bequest of (William Jones Rhees, 1913_.-_-_.__... 2 set 251. 95 Deposit of proceeds from sale of real estate (gift of Robert Stan- aTPAVCL VA) MLO pia asst o DA oh ke ee et ee 9, 692, 42 Total amount of fund in the United States Treasury__----~ 955, 500. 00 121 122 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. OTHER RESOURCES. Registered and guaranteed bonds of the West Shore Railroad Co., part of legacy of Thomas G. Hodgkins (par value) _____________ $42, 000. 00 Motel permeameter Ne ee ee ae ee Re 997, 500. 00 Also three small pieces of real estate bequeathed by Robert Stanton Avery, of Washington, D. C., one of the original four pieces and part of another haying been sold during the year and the proceeds deposited in the United States Treasury as an addition to the permanent fund. That part of the fund deposited in the Treasury of the United States’ bears interest at 6 per cent per annum, under the provisions of the act of Congress of August 10, 1846, organizing the Institution, and the act approved March 12, 1894. The rate of interest on the West Shore Railroad bonds.is 4 per cent per annum. The real estate received from Robert Stanton Avery is exempt from taxation and yields only a nominal revenue from rentals. Statement of receipts and disbursements from July 1, 1912, to June 80, 1913. RECEIPTS. Croteonsceposit wUly 1, 1912 280 ee ee ee $338, 060. 09 Interest on fund deposited in United States Treasury quer iulyelet Oia and Jan, 1, 1913-2. 0 een $56, 695. 12 Interest on West Shore Railroad bonds due July 1, 1912, PUR EOL Mme ACTINIUM ILO) Trey iu iy Wa Lh ee ld se, we a 1, 680. 00 Repayments, rentals, publications, sale of real estate, ete. 17, 920.12 Contributions from various sources for specific purposes_ 16, 575. 50 92, 870. 74 125, 930. 83 DISBURSEMENTS. Paces carerand: repairs... 2 eee 5, 715. 66 PUMEMMTIne AMO TXOUPeS 2.2 4 bP a ee A ee eee 1, 396. 97 General expenses : Sede INT NCS mpenmnenpeg a oe A er ors arr yore, ele $18, S04. 31 Sipe acanir eSrs poem rete oe CE ce SY ee 339. 00 IeRRE ORC UTpVpren epee tal eet So tN ee ce ee 810. 18 Postage, telegraph, and telephone____—~=—_--_-____ 710. 29 TIRES ai pees cree Sir ay ee A ee ee 98. 85 LE Eri Seat TSU US Sr ee 2 058s0e Rea TST e1)e acne ed Se toe a ee 2, 448. 74 TEU SulanG Us INES) 0 ches Pi LRT be EERE Pe 91. 26 ————— _ 25, 361. 10 TL LS EL eR epee Meee Mer ey Caen TIE: 2, 892. 50 Publications and their distribution: Miscellaneous: collections —..- 24.) 2. ee 4, 986. 32 JEX(E§ a0 TS) Sale a SI et AL Ase OEE Ses eee Pe 825.18 SHecla A pUDlICATIONS Lt kt sta easy ey Crees 454. 51 Publications supplies#.42— 2. + 3 ph ee ee 306. 27 SST ES Ce oe eS 8 CB eee LIE RE op 6, 558. 00 ————— _ 18, 110. 28 Dixplorations,, researches, and collections) 2220282 2.222 ee 20, 8938. 48 Hodgkins specifie fund, researches and publications_____________--_ 1, 664. 96 International’ Mxchanges 200 25 ook 2 ee ee ee 4, 289. 92 REPORT OF EXECUTIVE COMMITTEE. 123 (CREB Reyee Cag HIRANO Rae 2 BSC MUD es 0s oe da ep a $29. 63 a VoNEeS tor MelO EXPENSES, ELCs. 2 i. aah ee ee 6, 805. 67 Wepositeatorcredi of permanent fund 2.02 Ces ee 10, 581. 31 pene, aecrodynamical Uaboratory——-—- 90 2 48. 00 92, 289. 43 Balance, June 30, 19138, deposited with the Treasurer of the TTP ee gh [SURROGATE A la ee Nee aa Meee Ns LL 33, 641. 40 125, 930. 83 By authority your executive committee again employed Mr. Wil- liam L. Yaeger, a public accountant of this city, to audit the receipts and disbursements of the Smithsonian Institution during the period covered by this report. The following certificate of examination supports the foregoing statement, and is hereby approved: WASHINGTON, D. C., July 31, 1913. EXECUTIVE COMMITTEE BOARD OF REGENTS, Smithsonian Institution. Sirs: I have examined the accounts and vouchers of the Smithsonian Institu- tion for the fiscal year ending June 30, 1913, and certify the following to be a eorrect statement: areas ifrseemrnen ce Ne eee $92, STO. T4 VG GT STOTENES Cire SST Se TE ee 92, 289. 43 Excess of receipts over disbursements______________________ 581. 31 Seinen ner ihvenl | TOU 2 kee ed ee eee 33, 060. 09 Rainceronm hand sume oO, 1913-2. 33, 641. 40 Balance shown by Treasury statement June 30, 1918______________ 39, 342. 24 MMR TICIoO NCHeCKS: 222 be ot eee 5, 700. 84 erence: gune oO. LOTS. 2 an i el en oe ee 33, 641. 40 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 charged were applied to the purposes of the Institution, have been examined in con- nection with the books of the Institution and agree with them, excepting voucher No. 3514, to Andrew D. White for $50, which was canceled together with check after entry upon the books, for which credit will be given in July account. (Signed ) WILLIAM L. YAEGER, Public Accountant and Auditor. All moneys received by the Smithsonian Institution from interest, sales, refunding of moneys temporarily advanced, or otherwise, are deposited with the Treasurer of the United States to the credit of the Institution, and all payments are made by checks signed by the secretary. The expenditures made by the disbursing agent of the Institution and audited by the Auditor for the State and Other Departments are reported in detail to Congress and will be found in the printed document. 124 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. Your committee also presents the following summary of appro- priations for the fiscal year 1913 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, 1913: wars Balance July 1, 1912. June 30, 1913. $5. 02 1 $5.02 2,973.13 31 32, 090. 00 4,065. 41 580. 64 1365.51 2,576. 64 50.56 ee) sae b 09. 4. 3, 802. 73 612.59 13, 000 Be as 38 4.50 4.50 682.04 25.95 7,500. 00 681.58 MlevAtOrs Nutibosonian Building, 19UI 202221) 2} 2 ee eee oe 946.06 1946.06 National Museum— Mims angeixtures, 19M fe lice cn. swt ae eee Nae 287.04 1 287.04 HrmanITe yaa fixtures 1912.25. fave. ee cee ake eee 37, 359. 32 1,54 ete MOUS UTES 1913): os... ok seine reeks One seee tease eeenanee 50, 000. 00 11, 617.95 ean PrenOichtineIOUL oe. 2 5oc2 sec nese gees eahsece Sec eens 4,153.20 1 4,153.20 igs airs uae [i atedny pho At Up eae eee ee gee anon pee ere yg. 1S 4, 036. 43 124. 68 Delain at oy ita ba [ee Soe ee eet ae Sree os yrs 50, 000. 00 12, 689. 65 lerceervatiomorcollections, 1911.2... oo. secs ce cence geese mses seer 7,030. 94 11,132.28 ETeseVvanom OLcolechions, 1912 0. iio... ne eae enc eta seein 8, 932.37 1,355. 71 iareceivarionmoveolechions, 1913.00 02 2.0. 2. veal ook yee 300, 000. 00 17, 393.54 ES OORA LGM ieten Ne cists cesses cu cisteslnonte sesouse ce eb see ty aS Ey eas 42.76 114,97 TRYCIOL SS, LI A eer ne a NS ee ey aS 690. 30 26.54 TS EPN MMO EERE TNED tee ime noe se cea ceves ntlen cee cece ee cee se eee eee 2, 000. 00 845.21 LESS EBiy NETRA ng 900:00))|2c0 = eee emimamome pains, VOUT oc ites casa ealeinle oo Mage Soe ees 108.19 1108.19 PEMUGUTI OOD HITS ALO se icinc ble cosa cebes Leese esse eee eee seme eee 4,751.95 18. 44 Emp erOM AES MOIS ek ee eee tbls. Bee ee 10, 000. 00 576.05 PamGineeNaional Museum? : ; / Ad eae i) ie Lire ae les Ne pile at erat. >... sal GENERAL APPENDIX TO THE SMITHSONIAN REPORT FOR 1913 141 ADVERTISEMENT. The object of the GznrraL Aprenpix 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 annual report required of them by law with memoirs illustrating the more remarkable and important developments in physical and biological 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 publication 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 80 years previous had been issued by well-known private publishing firms, had prepared by com- petent collaborators a series of abstracts, showing concisely the prom- inent features of recent scientific progress in astronomy, geology, meteorology, physics, chemistry, mineralogy, botany, zoology, 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 original) embracing a considerable range of scientific investigation and dis- cussion. This method has been continued in the present report for 1913. 143 THE EARTH AND SUN AS MAGNETS: By Dr. GrorcGe. ELLERY HALE,’ Mount Wilson Solar Observatory. [ With 8 plates. ] In 1891 Prof. Arthur Schuster, speaking before the Royal Insti- tution, asked a question which has been widely debated in recent years: “Is every large rotating body a magnet?” Since the days of Gilbert, who first recognized that the earth is a great magnet, many theories have been advanced to account for its magnetic properties. Biot, in 1805, ascribed them to a relatively short magnet near its center. Gauss, after an extended mathematical investigation, sub- stituted a large number of small magnets, distributed in an irregu- lar manner, for the single magnet of Biot. Grover suggested that terrestrial magnetism may be caused by electric currents, circulating around the earth and generated by the solar radiation. Soon after Rowland’s demonstration in 1876, that a rotating electrically charged body produces a magnetic field, Ayrton and Perry attempted to apply this principle to the case of the earth. Rowland at once pointed out a mistake in their calculation, and showed that the high potential electric charge demanded by their theory could not possibly exist on the earth’s surface. It remained for Schuster to suggest that a body made up of molecules which are neutral in the ordinary electrical or magnetic sense may nevertheless develop magnetic prop- erties when rotated. We shall soon have occasion to examine the two hypotheses ad- vanced in support of this view. While both are promising, it can not be said that either has been sufficiently developed to explain com- pletely the principal phenomena of terrestrial magnetism. If we turn to experiment, we find that iron globes spun at great velocity in the laboratory fail to exhibit magnetic properties. But this can: be accounted for on either hypothesis. What we need is a globe of great size, which has been rotating for centuries at high velocity. The sun, with a diameter 100 times that of the earth (fig. 1), may 1Address delivered at the semicentennial of the National Academy of Sciences, at Washington, D. C., May, 1913. 2 The author had expected, before reprinting this address, to subject it to a thorough revision and to insert the results of recent observations, but he has been prevented by illIness from doing so. (Aug. 24, 1914.) 44863°—sMm 1913 10 145 146 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. throw some light on the problem. Its high temperature wholly pre- cludes the existence of permanent magnets, hence any magnetism it may exhibit must be due to motion. Its great mass and rapid linear velocity of rotation should produce a magnetic field much stronger than that of the earth. Finally, the presence in its atmosphere of glowing gases and the well-known effect of magnetism on light should enable us to explore its magnetic field even at the distance of the earth. The effects of ionization, probably small in the region of nigh pressure beneath the photosphere and marked in the solar atmos- phere, must be determined and allowed for. But with this important limitation the sun may be used by the physicist for an experiment which can not be performed in the best equipped laboratory. Schuster, in the lecture already cited, remarked: The form of the corona suggests a further hypothesis which, extravagant as it may appear at present, may yet prove to be true. Is the sun a magnet? Summing up the situation in April, 1912, he repeated: The evidence (whether the sun is a magnet) rests entirely on the form of certain rays of the corona, which—assuming that they indicate the path of pro- jecting particles—seem to be deflected as they would be in a magnetic field, but this evidence is not at all decisive. There remained the possibility of an appeal to a conclusive test of magnetism—the characteristic changes it produces in light which originates in a magnetic field. Before describing how this test has been applied, let us rapidly _ recapitulate some of the principal facts of terrestrial magnetism. You see upon the screen the image of a steel sphere (fig. 2), which has been strongly magnetized. If iron filings are sprinkled over the glass plate that supports it, each minute particle becomes a mag- net under the influence of the sphere. When the plate is tapped, to relieve the friction, the particles fall into place along the lines of force, revealing a characteristic pattern of great beauty. A small compass needle, moved about the sphere, always turns so as to point along the lines of force. At the magnetic poles it points toward the center of the sphere. Midway between them, at the equator, it is parallel to the diameter joining the poles. As the earth is a magnet it should exhibit lines of force resembling those of the sphere. If the magnetic poles coincided with the poles of rotation, a freely suspended magnetic needle should point ver- tically downward at one pole, vertically upward at the other, and horizontally at the equator. A dip needle, used to map the lines of force of the earth, is shown on the screen. I have chosen for illustration an instrument designed for use at sea, on the non- magnetic yacht Carnegie, partly because the equipment used by volume. Smithsonian Report, 1913.—Hale. PLATE 1. Fig. 1.—DIRECT PHOTOGRAPH OF THE SUN WITH DOT ONE MILLIMETER IN DIAMETER (NEAR LOWER LEFT CORNER) REPRESENTING THE EARTH FOR COMPARISON. Smithsonian Report, 1913.—Hale. PLATE 2. Fla. 2.—LINES OF FORCE OF A MAGNETIZED STEEL SPHERE. Fig. 3.—DIRECT PHOTOGRAPH OF PART OF THE SUN, APRIL 30, 1908. EARTH AND SUN AS MAGNETS—HALE. 147 Dr. Bauer in his extensive surveys represents the best now in use, and also because I wish to contrast the widely different means em- ployed by the Carnegie Institution for the investigation of solar and terrestrial magnetic phenomena. The support of the dip needle is hung in gimbals, so that observations may be taken when the ship’s deck is inclined. The smallest possible amount of metal enters into the construction of this vessel, and where its use could not be avoided, bronze was employed instead of iron or steel. She is thus admirably adapted for magnetic work, as is shown by the observations secured on voyages already totaling more than 100,000 miles. Her work is supplemented by that of land parties, bearing instruments to re- mote regions where magnetic observations have never before been made. The dip needle clearly shows that the earth is a magnet, for it behaves in nearly the same way as the little needle used in our ex- periment with the magnetized sphere. But the magnetic poles of the earth do not coincide with the geographical poles. The north magnetic pole, discovered by Ross and last visited by Amundsen in 1903, lies near Baflfins Bay, in latitude 70° north, longitude 97° west. The position of the south magnetic pole, calculated from observations made in its vicinity by Capt. Scott, of glorious memory, in his expedition of 1901-1904, is 72° 50’ south latitude, 153° 45’ east longitude. Thus the two magnetic poles are not only displaced about 30° from the geographical poles; they do not even lie on the same diameter of the earth. Moreover, they are not fixed in posi- tion, but appear to be rotating about the geographical poles in a period of about 900 years. In addition to these peculiarities, it must be added that the dip needle shows the existence of local mag- netic poles, one of which has recently been found by Dr. Bauer’s party at Treadwell Point, Alaska. At such a place the direction of the needle undergoes rapid change as it is moved about the local pole. The dip needle, as we have seen, is free to move in a vertical plane. The compass needle moves in a horizontal plane. In general, it tends to point toward the magnetic pole, and as this does not correspond with the geographical pole, there are not many places on the earth’s surface where the needle indicates true north and south. _ Local peculiarities, such as deposits of iron ore, also affect its direc- _ tion very materially. Thus a variation chart, which indicates the - deviation of the compass needle from geographical north, affords an excellent illustration of the irregularities of terrestrial magnetism. _ The necessity for frequent and accurate surveys of the earth’s mag- : netic field is illustrated by the fact that the Carnegie has found errors i of 5° or 6° in the variation charts of the Pacific and Indian Oceans. In view of the earth’s heterogeneous structure, which is sufficiently “strated by its topographical features, marked deviations from the SANG s 148 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. uniform magnetic properties of a magnetized steel sphere are not at all surprising. The phenomenon of the secular variation, or the rotation of the magnetic poles about the geographical poles, is one of the peculiarities toward the solution of which both theory and experiment should be directed. Passing over other remarkable phenomena of terrestrial mag- netism, we come to magnetic storms and auroras, which are almost certainly of solar origin. Here is a photograph of part of the sun, as it appears in the tele- scope (fig.3).1 Scattered over its surface are sun spots, which increase and decrease in number in a period of about 11.3 years. It is well known that a curve, showing the number of spots on the sun, is closely similar to a curve representing the variations of intensity of the earth’s magnetism. The time of maximum sun spots corresponds with that of reduced intensity of the earth’s magnetism, and the parallelism of the two curves is too close to be the result of accident. We may therefore conclude that there is some connection between the spotted area of the sun and the magnetic field of the earth. We shall consider a little later the nature of sun spots, but for the present we may regard them simply as solar storms. When spots are numerous the entire sun is disturbed, and eruptive phenomena, far transcending our most violent volcanic outbursts, are frequently visible. In the atmosphere of the sun, gaseous prominences rise to great heights. This one, reaching an elevation of 85,000 miles, is of the quiescent type, which changes gradually in form and is abun- dantly found at all phases of the sun’s activity. But such eruptions as the one of March 25, 1895, photographed with the spectrohelio- graph of the Kenwood Observatory, are clearly of an explosive na- ture. As these photographs show, it shot upward through a distance of 146,000 miles in 24 minutes, after which it faded away. When great and rapidly changing spots, usually accompanied by eruptive prominences, are observed on the sun, brilliant displays of the aurora (fig. 6) and violent magnetic storms are often reported. The magnetic needle, which would record a smooth straight line on the photographic film if it were at rest, trembles and vibrates, draw- ing a broken and irregular curve. Simultaneously, the aurora flashes and pulsates, sometimes lighting up the northern sky with the most brilliant display of red and green discharges. Birkeland and Stérmer have worked out a theory which accounts in a very satisfactory way for these phenomena. They suppose that electrified particles, shot out from the sun with great velocity, are drawn in toward the earth’s magnetic poles along the lines of force. Striking the rarified gases of the upper atmosphere, they illuminate 1 Figs. 3, 4, and 5 represent the same region of the sun, photographed at successively higher levels. , F EARTH AND SUN AS MAGNETS—HALE. 149 them, just as the electric discharge lights up a vacuum tube. There is reason to believe that the highest part of the earth’s atmosphere consists of rarified hydrogen, while nitrogen predominates at a lower level. Some of the electrons from the sun are absorbed in the hydrogen, above a height of 60 miles. Others reach the lower- lying nitrogen, and descend to levels from 30 to 40 miles above the earth’s surface. Certain still more penetrating rays sometimes reach an altitude of 25 miles, the lowest hitherto found for the aurora. The passage through the atmosphere of the electrons which cause the aurora also gives rise to the irregular disturbances of the mag- netic needle observed during magnetic storms. The outflow of electrons from the sun never ceases, if we may reason from the fact that the night sky is at all times feebly illumi- nated by the characteristic light of the aurora. But when sun spots are numerous, the discharge of electrons is most violent, thus ex- plaining the frequency of brilliant auroras and intense magnetic storms during sun-spot maxima. It should be remarked that the discharge of electrons does not necessarily occur from the spots themselves, but rather from the eruptive regions surrounding them. Our acquaintance with vacuum-tube discharges dates from an early period, but accurate knowledge of these phenomena may be said to begin with the work of Sir William Crookes in 1876. A glass tube, fitted with electrodes, and filled with any gas, is exhausted with a suitable pump until the pressure within it is very low. When a high- voltage discharge is passed through the tube, a stream of negatively charged particles is shot out from the cathode, or negative pole, with great velocity. These electrons, bombarding the molecules of the gas within the tube, produce a brillant illumination, the character of which depends upon the nature of the gas. The rare hydrogen gas in the upper atmosphere of the earth, when bombarded by electrons from the sun, glows like the hydrogen in this tube. Nitrogen, which is characteristic of a lower level, shines with the light which can be duplicated here. But it may be remarked that this explanation of the aurora is only hypothetical, in the absence of direct evidence of the emission of electrons by the sun. However, we do know that hot bodies emit electrons. Here is a carbon filament in an exhausted bulb. When heated white hot a stream of electrons passes off. Falling upon this electrode the electrons discharge the electroscope with which it is connected. Everyone who has to discard old incandescent lamps is familiar with the result of this outflow. The blackening of the bulbs is due to finely divided carbon carried away by the electrons and deposited upon the glass. _ Now, we know that great quantities of carbon in a vaporous state exist in the sun and that many other substances also present there 150 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. emit electrons in the same way. Hence we may infer that electrons are abundant in the solar atmosphere. The temperature of the sun is between 6,000° and 7,000° C., twice as high as we can obtain by artificial means. Under solar condi- tions, the velocity of the electrons emitted in regions where the pres- sure is not too great may be sufficient to carry them to the earth. Arrhenius holds that the electrons attach themselves to molecules or groups of molecules and are then driven to the earth by lght pressure. In certain regions of the sun we have strong evidence of the existence of free electrons. This leads us to the question of solar magnetism and suggests a comparison of the very different condi- tions in the sun and earth. Much alike in chemical composition, these bodies differ principally in size, in density, and in temperature. The diameter of the sun is more than 100 times that of the earth, while its density is only one-quarter as great. But the most striking point of difference is the high temperature of the sun, which is much more than sufficient to vaporize all known substances. This means that no permanent magnetism, such as is exhibited by a steel magnet or a lodestone, can exist in the sun. For if we bring this steel magnet to a red heat it loses its magnetism and drops the iron bar which it previously supported. Hence, while some theories attribute ter- restrial magnetism -to the presence within the earth of permanent magnets, no such theory can apply to the sun. If magnetic phe- nomena are to be found there they must result from other causes. The familiar case of the helix illustrates how a magnetic field is produced by an electric current flowing through a coil of wire. But according to the modern theory, an electric current is a stream of electrons. Thus a stream of electrons in the sun should give rise to a magnetic field. If the electrons were whirled in a powerful vortex, resembling our tornadoes or waterspouts, the analogy with the wire helix would be exact, and the magnetic field might be sufficiently intense to be detected by spectroscopic observations. A sun spot, as seen with a telescope or photographed in the ordi- nary way, does not appear to be a vortex. If we examine the solar atmosphere above and about the spots, we find extensive clouds of luminous calcium vapor, invisible to the eye, but easily photographed with the spectroheliograph by admitting no lght to the sensitive plate except that radiated by calcium vapor. These calcium floceuli (fig. 4), like the cumulus clouds of the earth’s atmosphere, exhibit no well-defined linear structure. But if we photograph the sun with the red light of hydrogen, we find a very different condition of affairs (fig. 5). In this higher region of the solar atmosphere, first photo- graphed on Mount Wilson in 1908, cyclonic whirls, centering in sun spots, are clearly shown. Smithsonian Report, 1913.—Hale. PLATE 3. Fic. 4.—SAME REGION OF THE SUN SHOWING THE CALCIUM (Hz) FLOCCULI. Fig. 5.—SAME REGION OF THE SUN SHOWING THE HYDROGEN (Ha) FLoccut. Smithsonian Report, 1913.—Hale. PLATE 4, Fic. 6.—THE AURORA. Fic. 7.—WATER SPOUT. BARTH AND SUN AS MAGNETS—HALR. 151 The idea that sun spots may be solar tornadoes, which was strongly suggested by such photographs, soon received striking confirmation. A great cloud of hydrogen, which had hung for several days on the edge of one of these vortex structures, was suddenly swept into the spot at a velocity of about 60 miles per second. More recently Slocum has photographed at the Yerkes Observatory a prominence at the edge of the sun, flowing into a spot with a somewhat lower velocity. Thus we were led to the hypothesis that sun spots are closely analogous to tornadoes or waterspouts in the earth’s atmosphere (fig. 7). If this were true, electrons caught and whirled in the spot vortex should produce a magnetic field. Fortunately, this could be put to a conclusive test through the well-known influence of mag- netism on light discovered by Zeeman in 1896. In Zeeman’s experiment a flame containing sodium vapor was placed between the poles of a powerful electromagnet. The two yellow sodium lines, observed with a spectroscope of high dispersion, were seen to widen the instant a magnetic field was produced by pass- ing a current through the coils of the magnet. It was subsequently found that most of the lines of the spectrum, which are single under ordinary conditions, are split into three components when the radiating source is in a sufficiently intense magnetic field. This is the case when the observation is made at right angles to the lines of force. When looking along the lines of force, the central line of such a triplet disappears (fig. 8), and the light of the two side com- ponents is found to be circularly polarized in opposite directions. With suitable polarizing apparatus, either component of such a line can be cut off at will, leaving the other unchanged. Furthermore, a double line having these characteristic properties can be produced only by a magnetic field. Thus it becomes a simple matter to detect a magnetic field at any distance by observing its effect on light emitted within the field. If a sun spot is an electric vortex, and the observer is supposed to look along the axis of the whirling vapor, which would correspond with the direction of the lines of force, he should find the spectrum lines double, and be able to cut off either component with the palarizing attachment of his spectroscope. I applied this test to sun spots on Mount Wilson in June, 1908, with the 60-foot tower telescope, and at once found all of the char- acteristic features of the Zeeman effect. Most of the lines of the sun-spot spectrum are merely widened by the magnetic field, but others are split into separate components (fig. 9), which can be cut off at will by the observer. Moreover, the opportune formation of two large spots, which appeared on the spectroheliograph plates to be rotating in opposite directions (fig. 10), permitted a still more exacting experiment to be tried. In the laboratory, where the polar- 152 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. izing apparatus is so adjusted as to transmit one component of a tine doubled by a magnetic field, this disappears and is replaced by the other component when the direction of the current is reversed. In other words, one component is visible alone when the observer looks toward the north pole of the magnet, while the other appears alone when he looks toward the south pole. If electrons of the same kind are rotating in opposite directions in two sun-spot vortexes, the observer should be looking toward a north pole in one spot and to- ward a south pole in the other. Hence the opposite components of a magnetic double line should appear in two such spots. As our photographs show, the result of the test was in harmony with my anticipation. I may not pause to describe the later developments of this investi- gation, though two or three points must be mentioned. The intensity of the magnetic field in sun spots is sometimes as high as 4,500 gausses, or 9,000 times the intensity of the earth’s field. In passing upward from the sun’s surface the magnetic intensity de- creases very rapidly—so rapidly, in fact as to suggest the existence of an opposing field. It is probable that the vortex which produces the observed field is not the one that appears on our photograph, but lies at a lower level. In fact, the vortex structure shown on spectro- heliograph plates may represent the effect rather than the cause of the sun-spot field. We may have, as Brester and Deslandres suggest, a condition analogous to that illustrated in the aurora: Electrons, falling in the solar atmosphere, move along the lines of force of the magnetic field into spots. In this way we may perhaps account for the structure surrounding pairs of spots, of opposite polarity, which constitute the typical sun-spot group. The resemblance of the struc- ture near these two bipolar groups to the lines of force about a bar magnet is very striking, especially when the disturbed condition-of the solar atmosphere, which tends to mask the effect, is borne in mind. It is not unlikely that the bipolar group is due to a single vortex, of the horseshoe type, such as we may see in water after every sweep of an oar. We thus have abundant evidence of the existence on the sun of local magnetic fields of great intensity—fields so extensive that the earth is small in comparison with many of them. But how may we account for the copious supply of electrons needed to generate the powerful currents required in such enormous electromagnets? Neu- tral molecules, postulated in theories of the earth’s field, will not suffice. A marked preponderance of electrons of one sign is clearly indicated. An interesting experiment, due to Harker, will help us here. Imagine a pair of carbon rods insulated within a furnace heated to a temperature of two or three thousand degrees. The outer ends of Smithsonian Report, 1913.—Hale. PLATE 5. | . | Fia. 8.—ZEEMAN DOUBLET PHOTOGRAPHED IN LABORATORY SPECTRUM. The middle section shows the doublet. The adjacent sections indicate the appearance of the spectrum line in the absence of a magnetic field. Fia. 9.—a, b, SPECTRA OF TWO SUN SPOTS. The triple line indicates a magnetic field of 4,500 gausses in a and of 2,900 gausses in b. Smithsonian Report, 1913.—Hale. PLATE 6. aap r fo om Fic. 10.—RIGHT AND LEFT HANDED VORTEXES SURROUNDING SUN SPOTS, AS INDICATED BY THE DISTRIBUTION OF HYDROGEN GAS. Photographed with the spectroheliograph. Fic. 11.—SOLAR CORONA SHOWING POLAR STREAMERS. BARTH AND SUN AS MAGNETS—HALRBE. 158 the rods projecting from the furnace are connected toa galvanometer. Harker found that when one of the carbon terminals within the fur- nace was cooler than the other a stream of negative electrons flowed toward it from the hotter electrode. Even at atmospheric pressure currents of several amperes were produced in this way.t Our spectroscopic investigations, interpreted by laboratory experi- ments, are in harmony with those of Fowler in proving that sun spots are comparatively cool regions in the solar atmosphere. They are hot enough, it is true, to volatilize such refractory elements as titanium, but cool enough to permit the formation of certain com- pounds not found elsewhere in the sun. Hence, from Harker’s ex- periment, we may expect a flow of negative electrons toward spots. These, caught and whirled in the vortex, would easily account for the observed magnetic fields. The conditions existing in sun spots are thus without any close parallel among the natural phenomena of the earth. The sun-spot vortex is not unlike a terrestial tornado, on a vast scale, but if the whirl of ions in a tornado produces a magnetic field, it is too feeble to be readily detected. Thus, while we have demonstrated the ex- istence of solar magnetism, it is confined to limited areas. We must look further if we would throw new light on the theory of the mag- netic properties of rotating bodies. This leads us to the question with which we atatteel: Ts the sun a magnet, like the earth? The structure of the corona, as revealed at total eclipses, points strongly in this direction. Remembering the lines of force of our magnetized steel sphere, we can not fail to be struck by their close resemblance to the polar streamers in these beautiful photographs of the corona (fig. 11) taken by Lick Observa- tory eclipse parties, for which I am indebted to Prof. Campbell. Bigelow, in 1889, investigated this coronal structure and showed that it is very similar to the lines of force of a spherical magnet. Stormer, guided by his own researches on the aurora, has calculated the tra- jectories of electrons moving out from the sun under the influence of a general magnetic field and compared these trajectories with the coronal streamers. The resemblance is apparently too close to be the result of chance. Finally, Deslandres has investigated the forms and motion of solar prominences, which he finds to behave as they would in a magnetic field of intensity about one-millionth that of the earth. We may thus infer the existence of a general solar magnetic field. But since the sign of the charge of the outflowing electrons is not certainly known, we can not determine the polarity of the sun in this way. Furthermore, our present uncertainty as to the propor- tion at different levels of positive and negative electrons and of the 1 King has recently found that the current decreases very rapidly as the pressure in- creases, but is still appreciable at a pressure of 20 atmospheres. 154 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. perturbations due to currents in the solar atmosphere must delay the most effective application of these methods, though they promise much future knowledge of the magnetic field at high levels in sa solar atmosphere. Of the field at low levels, however, they may tell us little or noth- ing, for the distribution of the electrons may easily be such as to give rise to a field caused by the rotation of the solar atmosphere, which may oppose in sign the field due to the rotation of the body of the sun. To detect this latter field, the magnetic field of the sun as distinguished from that of the sun’s atmosphere, we must resort to the method employed in the case of sun spots—the study of the Zeeman effect. If this is successful it will not only show beyond doubt whether the sun is a magnet; it will also permit the polarity of the sun to be compared with that of the earth, gives a measure of the strength of the field at different latitudes and indicate the sign of the charge that a rotating sphere must possess if it is to produce a similar field. I first endeavored to apply this test with the 60-foot tower tele- scope in 1908, but the results were too uncertain to command con- fidence. Thanks to additional appropriations from the Carnegie Institute of Washington, a new and powerful instrument was available on Mount Wilson for a continuation of the investigation in January, 1912. The new tower telescope has a focal length of 150 feet (fig. 12). To prevent vibration in the wind, the ccelostat, second mirror, and object glass are carried by a skeleton tower, each vertical and diagonal member of which is inclosed within the corresponding member of an outer skeleton tower, which also carries a dome to shield the instruments from the weather. In the photograph we see only the hollow members of the outer tower. But within each of them, well separated from possible contact, a sectional view would show the similar but more slender members of the tower that sup- port the instruments. The plan has proved to be successful, per- mitting observations demanding the greatest steadiness of the solar image to be made. The arrangements are similar to those of the 60-foot tower. The solar image, 164 inches in diameter, falls on the slit of a spectro- graph (fig. 13) in the observation house at the ground level. The spectrograph, of 75 feet focal length, enjoys the advantage of great stability and constancy of temperature in its subterranean vault beneath the tower. In the third order spectrum, used for this in- vestigation, the D lines of the solar spectrum are 29 millimeters apart. The resolving power of the excellent Michelson grating is sufficient to show 75 lines of the iodine absorption spectrum in this space between the D’s. Thus the instruments are well suited for ws oS ee me a he PLATE 7. Smithsonian Report, 1913.—Hale. Foot TOWER TELESCOPE 2.—150- Fia. 1 Smithsonian Report, 1913.—Hale. PLATE 8. Fic. 13.—HEAD OF THE 75-FOOT SPECTOGRAPH OF THE 150-FootT Tower > TELESCOPE. Equator. He ele a ee FEEEHH Fig. 14.—THE Curve REPRESENTS THE THEORETICAL VARIATION OF THE DIS- PLACEMENTS OF SPECTRUM LINES WITH THE HELIOGRAPHIC LATITUDE. The sun is assumed to be a magnetic sphere with its magnetic poles coinciding with the poles of rotation. The points represent mean yalues of the observed displacements. Vertical scale: 1 square = 0,001 mm. = 0.0002 Angstrém., EARTH AND SUN AS MAGNETS—HALE. P55 the exacting requirements of a difficult investigation. For it must be borne in mind that the problem is very different from that of detecting the magnetic fields in sun spots, where the separation of the lines is from 50 to 100 times as great as we may expect to find here. Thus the sun’s general field can produce no actual separa- tion of the lines. But it may cause a very slight widening, which should appear as a displacement when suitable polarizing apparatus is used. This is so arranged as to divide the spectrum longitudi- nally into narrow strips. The component toward the red end of the spectrum of a line widened by magnetism should appear in one strip, the other component in the next strip. Hence, if the sun has a magnetic field of sufficient strength, the line should have a dentated appearance. The small relative displacements of the lines on suc- cessive strips, when measured under a microscope, should give the strength of the magnetic field. The above remarks apply strictly to the case when the observer is looking directly along the lines of force. At other angles neither component is completely cut off, and the magnitude of the displace- ment will then depend upon two things: The strength of the mag- netic field and the angle between the line of sight and the lines of force. Assuming that the lines of force of the sun correspond with those of a magnetized sphere, and also that the magnetic poles coin- cide with the poles of rotation, it is possible to calculate what the relative displacement should be at different solar latitudes. These theoretical displacements are shown graphically by the sine curve on the screen (fig. 14). We see from the curve that the greatest displacements should be found at 45° north and south latitude, and that from these points they should decrease toward zero at the equator and the poles. Fur- thermore, the curve shows that we may apply the same crucial test used in the case of sun spots; the direction of the displacements, toward red or violet, should be reversed in the northern and southern hemispheres. TI shall not trouble you with the details of the hundreds of photo- graphs and the thousands of measures which have been made by my colleagues and myself during the past year. In view of the diffuse character of the solar lines under such high dispersion and the ex- ceedingly small displacements observed, the results must be given with some reserve, though they appear to leave no doubt as to the reality of the effect. Observations in the second order spectrum failed to give satisfactory indications of the field. But with the higher dispersion of the third order 11 independent determinations, made with every possible precaution to eliminate bias, show opposite displacements in the northern and southern hemispheres decreasing in magnitude from about 45° north and south latitude to the equator. 156 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. Three of these determinations were pushed as close to the poles as conditions would permit, and the observed displacements may be compared with the theoretical curve (fig. 14). In view of the very small magnitude of the displacements, which never surpass 0.002 Angstroms, the agreement is quite as satisfactory as one could expect for a first approximation. The full details of the investigation are given in a paper recently published.t| The reader will find an account of the precautions taken to eliminate error, and, I trust, no tendency to underestimate the possible adverse bearing of certain negative results. It must remain for the future to confirm or to overthrow.the apparently strong evidence in favor of the existence of a true Zeeman effect, due to the general magnetic field of the sun. If this evidence can be accepted, we may draw certain conclusions of present interest. Taking the measures at their face value, they indicate that the north magnetic pole of the sun les at or near the north pole of rota- tion, while the south magnetic pole les at or near the south pole of rotation. In other words, if a compass needle could withstand the solar temperature, it would point approximately as it does on the earth, since the polarity of the two bodies appears to be the same. Thus, since the earth and sun rotate in the same direction, a negative charge distributed through their mass would account in each case for the observed magnetic polarity. As for the strength of the sun’s field, only three preliminary deter- minations have yet been made, with as many different lines. Disre- garding the systematic error of measurement, which is still very uncertain, these indicate that the field strength at the sun’s poles is of the order of 50 gausses (about 80 times that of the earth). Schuster, assuming the magnetic fields of the earth and sun to be due to their rotation, found that the strength of the sun’s field should be 440 times that of the earth, or 264 gausses. This was on the sup- position that the field strength of a rotating body is proportional to the product of the radius and the maximum linear velocity of rota- tion, but neglected the density. Before inquiring why the observed and theoretical values differ, we may glance at the two most prom- ising hypotheses that have been advanced in support of the view that every large rotating body is a magnet. On account of their greater mass, the positive electrons of the neutral molecules within the earth may perhaps be more powerfully attracted by gravitation than the negative electrons. In this case the negative charge of each molecule should be a little farther from the center of the earth than the positive charge. The average linear velocity of the negative charge would thus be a little greater, and the magnetizing effect due to its motion would slightly exceed that 1Contributions from the Mount Wilson Solar Observatory, No. 71. EARTH AND SUN AS MAGNETS—HALE. £57 due to the motion of the positive charge. By assuming a separation of the charges equal to about four-tenths the radius of a molecule (Bauer), the symmetrical part of the earth’s magnetic field could be accounted for as the result of the axial rotation. This theory, first suggested by Thomson, has been developed by Sutherland, Schuster, and Bauer. But as yet it has yielded no ex- planation of the secular variation of the earth’s magnetism, and the merits of other theories must not be overlooked. Chief among these is the theory that rests on the very probable assumption that every molecule is a magnet. If the magnetism is accounted for as the effect of the rapid revolution of electrons within the molecule, a gyrostatic action might be anticipated. That is, each molecule would tend to set itself with its axis parallel to the axis of the earth, just as the gyrostatic compass, now coming into use at sea, tends to point to the geographical pole. The host of molecular mag- nets, all acting together, might account for the earth’s magnetic field. This theory, in its turn, is not free from obvious points of weak- ness, though they may disappear as the result of more extended in- vestigation. Its chief advantage lies in the possibility that it may explain the secular variation of the earth’s magnetism by a preces- sional motion of the magnetic molecules. On either hypothesis, it is assumed, in the absence of knowledge to the contrary, that every molecule contributes to the production of the magnetic field. Thus the density of the rotating body may prove to be a factor. Perhaps the change of density from the surface to the center of the sun must also be taken into account. But the observa- tional results already obtained suggest that the phenomena of ioniza- tion in the solar atmosphere may turn out to be the predominant in- fluence. The lines which show the Zeeman effect originate at a compara- tively low level in the solar atmosphere. Preliminary measures indi- cate that certain lines of titanium, which are widely separated by a magnetic field in the laboratory, are not appreciably affected in the sun. As these lines represent a somewhat higher level, it is probable that the strength of the sun’s field decreases very rapidly in passing upward from the surface of the photosphere—a conclusion in har- mony with results obtained from the study of the corona and prom- inences. Thus it may be found that the distribution of the electrons is such as to give rise to the observed field or to produce a field oppos- ing that caused by the rotation of the body of the sun. It is evident that speculation along these lines may advantageously await the ac- cumulation of observations covering a wide range of level. Beneath the photosphere, where the pressure is high, we may conclude from recent electric furnace experiments by King that free electrons, though relatively few, may nevertheless play some part in the pro- duction of the general magnetic field. 158 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. In this survey of magnetic phenomena we have kept constantly in mind the hypothesis that the magnetism of the earth is due to its rotation. Permanent magnets, formerly supposed to account for the earth’s magnetic field, could not exist at the high temperature of the sun. Displays of the aurora, usually accompanied by mag- netic storms, are plausibly attributed to electrons reaching the earth from the sun, and illuminating the rare gases of the upper atmos- phere just as they affect those in a vacuum tube. Definite proof of the existence of free electrons in the sun is afforded by the discovery of powerful local magnetic fields in sun spots, where the magnetic intensity is sometimes as great as nine thousand times that of the earth’s field. These local fields probably result from the rapid revo- lution in a vortex of negative electrons, flowing toward the cooler spot from the hotter region outside. The same method of observa- tion now indicates that the whole sun is a magnet, of the same polarity as the earth. Because of the high solar temperature, this magnetism may be ascribed to the sun’s axial rotation. It is not improbable that the earth’s magnetism also results from its rotation, and that other rotating celestial bodies, such as stars and nebule, may ultimately be found to possess magnetic properties. Thus, while the presence of free electrons in the sun prevents our acceptance of the evidence as a proof that every large rotating body is a magnet, the results of the investigation are not opposed to this hypothesis, which may be tested further by the study of other stars of known diameter and velocity of rotation. numberless local magnetic fields, caused by electric vortices in the solar “ pores,’’ though at first sight improbable, deserves further consideration. THE REACTION OF THE PLANETS UPON THE SUN.' By P. Pursrux,’ Member of the Institute, Astronomer at the Paris Observatory. The popular preconception that the earth, with the sun rotating about it, was the center of the universe, was overcome only through the persistent efforts of astronomers and physicists. We will not here review these memorable discussions, but will note merely the result. Everyone capable of connected and geometrical reasoning will become convinced that the position of the earth, face to face with the sun, is that of a humble satellite, and that our globe, forced to escort our daytime star in its mysterious course through space, receives from this star its law of annual movement and at the same time its indispensable ration of heat and light. Going from one extreme to another, the sun was believed to be _ independent of the relatively minute planets which it carries along with itself. It seemed that a fictitious observer, placed at its center or on its surface, would have no occasion to suspect the existence of other celestial bodies. Further protected against any perceptible action from the stars by their immense distance, the sun must lavish its splendor, with no pay in return, and follow unperturbed its undeviated path through space. THE INFLUENCE OF THE PLANETS ON THE MOTION OF THE SUN. This conclusion was in some respects too radical. An account of this matter could be rendered only when the penetrating genius of Newton showed that the curved trajectory of a projectile, the revo- lution of the moon about the earth, and the revolution of the earth around the sun were three manifestations of the same law. This law holds everywhere. Further, it is not a special privilege of the center of any system. The bond exists, real though slight, between any two particles whatever. The sun, as well as the humblest _ planet, because of this bond, must undergo periodic variations in its speed as well as in its shape. 1 Lecture delivered at the Conservatoire des Arts et Métiers, Feb. 23, 1913. 2 Translated by permission from Revue Scientifique, Paris, May 3, 1913. 159 160 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, Have we to-day at our disposal sufficiently delicate means of obser- vations to detect these changes? In Newton’s time such means were probably lacking. The caprices of our atmosphere furnished a ready explanation of the apparent fluctuations in solar radiation. The spots had been observed on the sun’s disk, sometimes few, sometimes many, but no law had been assigned to them. Further, the tradi- tional fixity of the constellations led to the belief that the sun main- tained a complete immobility with reference to the stars. But the problem plainly stated aroused new attempts at its un- raveling. Bradley, a fellow countryman and a disciple of Newton, showed that much greater precision could be obtained in the measures of the angular distances of the stars than had before been gained. Less than a century later, W. Herschel could affirm that the con- stellations do alter their form, and the best determination of these changes may be explained by attributing to the solar system a regular rectilinear motion. The ambition of astronomers, increasing with success, tries to-day to show that this movement is not rigorously uniform, and even though shielded from the action of the stars, pays tribute to the universal attraction in periodic oscillations. It is pretty safe to predict what will be the most marked of these oscillations. It is not the center of the sun itself which possesses the uniform rectilinear motion, but the center of gravity of the system formed by the sun and all the planets. The oscillation would be small if only the earth need be considered. There is, however, a giant planet, Jupiter, whose mass exceeds that of all of the other planets taken together and is nearly one one-thousandth that of the sun. Describing its orbit at the rate of 12 kilometers per second, Jupiter forces the sun to rotate about an imaginary center with a velocity a thousand times less. This is apparently a very small amount, but not at all negligible with respect to the velocity of translation of the solar system, which is 20 kilometers per second. Consequently the speed of the solar system toward a point in the constellation Hercules is sometimes accelerated, sometimes slowed, by one part in one thousand in an interval of six years. Very few of the stars are near enough to us for the parallactic dis- placement relative to the more distant stars and due to this motion of the sun to be appreciable in six years. Consequently, to measure one one-thousandth part of this displacement is beyond the resources of precise astronomy. We may be pretty sure, though, that some day we will thus obtain, at the same time with a measure of the mass of Jupiter, a new confirmation of the principle of the universal attraction of gravitation. Meanwhile help comes in another way. What the micrometer for a long time will probably be unable to give, the spectroscope is al- ready furnishing. Although the variation of 30 meters per second, REACTION OF PLANETS UPON SUN—PUISEUX. 161 which we wish to detect in the motion of the sun, requires years to change sensibly the apparent position of a star, it takes only a moment to alter the quality of its light. Whatever the distance, the light waves will come to us sometimes more frequently, sometimes less; their path through a prism will consequently be found altered and the fine metallic lines of the spectrum recorded by a photograph will be displaced relatively to those of a stationary source, such as an elec- tric spark used for comparison. The earliest happy applications of this principle were due to Hug- gins and to Vogel. It was used to separate numerous double stars composed of pairs of suns so close to each other and so distant from us that each pair appeared as a single star. But the brightness of each was sufficient to record a spectrum and the relative velocities were sufficiently variable so that two spectrum lines of the same chemical origin separated periodically. Subsequently another class, yet greater in number, was found in which the spectrum lines were not doubled, but showed a periodic oscillation. In this case we may suppose that one of the two stars, while not bright enough to reg- ister its spectrum, is yet heavy enough to sway its associate. The period is usually several weeks or days. The displacements of the lines correspond to velocities of the same order as those of the planets, from 10 to 100 kilometers per second. Because of the ex- treme accuracy and care in the use of spectroscopes, certain as- tronomers can now measure velocities to a fraction of a kilometer. The time will come when pairs like the sun and Jupiter can be detected, however distant they may be, provided only that the prin- cipal star is bright enough to record its spectrum. Campbell, who is the leader in this class of research, estimates that on the average one star in three will be found spectroscopically double. It is very probable that even more stars art double since we can see no reason why a planet like Jupiter should be exceptional. We may predict that all stellar spectra will be found thus variable even after cor- recting for the orbital movement of the earth. We may then gather photographic evidence of the existence of planets about the stars as well as the periodic oscillation of our sun due to Jupiter. The earth of course will produce a similar effect only less in amplitude and period. But who would dare to put a limit to the skill of our opti- cians or the patience of our astronomers in a path so definitely marked out? THE PLANETS AS THE CAUSE OF THE SOLAR CYCLE. To find that we disturb the sun is of course something to elate us. We will feel perhaps a more tangible satisfaction if we can find that we cause changes in the aspect of its surface, disturbances visi- ble by direct and not indirect evidence in the field of the microscope. 44863°—sm 1913——11 . 162 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. We will now consider a deforming action dependent also on Newton’s law but of a differential nature and consequently propor- tional to the inverse cube instead of the inverse square of the distance. This difference helps to compensate for the inferiority of the mass of the earth with reference to the greater planets and gives it a chance for an honorable rank in this contest. We have under our eyes an encouraging phenomenon. The attrac- tion at the surface of the earth due to the sun is but a small fraction compared to the weight of a body here, and the yet feebler attraction due to the moon can not lighten a body by one one-hundred thou- sandth part of its weight. Yet we see the moon exerting this power and indeed with three times more strength than is felt from the sun, in deforming our globe. This action can be detected upon the atmos- phere, the oceans, and even the solid crust of the earth. The seas, however, are what render it most evident to our eyes. Under favor- able conditions, for instance, in the Bay of Mount St. Michel, on the French coast, we see the sea following faithfully the passage of the moon across the meridan. The sea’s level changes at the flood some 20 meters in a few hours, displacing the shoreline several kilometers. The work thus developed, if we could only put it to use economically, would be enough to render useless all our oil wells and all the engines in the world. We may find that no planet is as favorably situated to trouble the sun as the moon is the earth. But perhaps we should not be so ex- acting. We see upon the sun no such liquid seas which might be made to extend or contract their domains. The weight there to be conquered is great, 27 times greater than here. Despite that, we see chances that the sun may react as actively, or even more actively, than the earth, under the action of a distant body. ‘We are indeed led by several converging paths of reasoning to think that the sur- face layers of the sun are to a great depth formed of extremely tenu- ous mobile matter, little subject to the action of weight and all ready, consequently, to obey the least force. A first piece of evidence along this line is the development of spots, rents which seem to appear in the luminous veil of the solar surface, reaching in a few days an extent of ten, twenty, or thirty thousand kilometers and disappearing with equal rapidity. In the spectrum of these spots there is an increase in the number and intensity of the absorption bands, leading us to think that various metallic molecules of considerable atomic weight are spouted out in torrents, carried along by currents of the lighter hydrogen. More impressive yet is the appearance of protuberances—clouds which develop and remain at heights where they could not be sus- tained by the dense and refringent atmosphere. Much less bright REACTION OF PLANETS UPON SUN—PUISEUX. 163 than the disk, they have a special spectrum and during total eclipses are the principal source of light. We can now photograph them at any time about the edge of the disk by an ingenious method devised in 1868 by Janssen and by Lockyer and since singularly perfected. On many occasions we have been assured by incontestable evidence that protuberances can mount in a few hours in the form of vertical jets, narrow at the base to prodigious heights—50,000 to 100,000 kilometers or even more. Generally, however, before attaining such heights the protuberances expand into sheaves or stratified layers. At times they seem to be the seat of violent explosions, are scattered, and disappear very quickly. The spectroscope shows us that cal- cium vapor, despite its atomic weight 40 times heavier than that of hydrogen, rises very high in the protuberances. The displacements of the spectrum lines also furnish confirmation of the enormous velocities (100 kilometers or more per second) which the deforma- tions of the contours suggest. Total eclipses, during which protuberances first attracted atten- tion, are even now the only occasions when we can see another inter- esting phase of solar activity—the solar corona. Sometimes it appears as a halo somewhat equally distributed around the disk, at other times as gigantic streamers stretching out distances several times the diameter of the sun. The forms of these rays indicate that the matter of which they are composed shows no haste in falling back into the sun. This matter is evidently very sparse and has very Little absorptive action on light, for, despite its irregular distribution, it causes no difference in the appearance of the various parts of the disk. Its mobility must be very great since in the interval of two or three years between eclipses its structure completely changes, as our photographs assure us. Spots, protuberances, and corona are subject to a great variation which takes place regularly about nine times in a century. After a period when the sun’s disk appears entirely immaculate, spots re- appear in both hemispheres at latitudes from 20° to 30°, then, always increasing, they invade the equatorial regions, becoming at the max- imum 20 times more numerous on the average than in a minimum year. Then, as the decline commences, the numerical predominance, which the Northern Hemisphere at first seemed to show, passes to the Southern Hemisphere. The spots first disappear in the high lati- tudes and then diminish all over the sun. The protuberances pass through a similar cycle, except that dur- ing the period while their number increases their mean latitude tends _to increase in each hemisphere. Toward the epoch of spot maximum, and only then, it is not rare to see great protuberances even near the poles, where spots never appear. 164 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. The corona during the same period always undergoes a definite evolution. Toward the epoch of sun-spot minimum the polar rays are fine and vertical like the bristles of a brush. The jets in the mid- dle and mean latitudes are much longer and bent toward the Equator. At the maximum period there is little difference with the latitude. During the transition years the poles and the Equator are almost clear and the rays are developed only in the middle latitudes, giving the whole a rectangular appearance. The more we reflect upon these facts the less are we led to regard the sun as a monarch, inaccessible, and shut up in a tower of ivory. It, like the earth, must have seasons connected with the revolution of the planets and tides connected with its own rotation. To sift out at least the more active of these external influences is a legitimate task, even though it is not an easy one. ' First, do we find one or several bodies which could be held responsi- ble for a cycle of 11 years? The stars seem to be beyond considera- tion, since in that period there is no appreciable change in their linear or angular distances. We could, as did John Herschel, blame one or several swarms of meteors, imagined for the purpose. Describing very eccentric orbits, they might graze the surface of the sun, causing the spots. Suitably choosing their revolution periods, inclinations, eccentricities, and the distribution of the matter in their orbits, we could explain the phenomenon in all its details. We must confess that the permanence of swarms of meteors put every 11 years to such a violent test does not seem probable. There is no doubt that meteors fall into the sun in great numbers. But we have no direct proof that this happens periodically and so as to produce visible effects. Such proof we feel that we must demand for this very supple and convenient hypothesis. As these swarms have not been detected, we must leave them and direct our investigations to the planets. The most important of these planets brings a coincidence at first sight very seductive. Nearly every 11 years Jupiter, in a determinate sense, crosses the plane of the solar equator; also in every 11 years the numerical predominance of the spots passes from the northern to the southern hemisphere of the sun. The same interval separates the return of Jupiter to its least distance from the sun and the return of the sun-spot numbers to their extreme value. We must not hurry, though, to sing our victory. It is not an approximate concordance but a precise one which we should demand. The periods in years are 11.86 for the revolution of Jupiter and 11.13 for the sun-spot cycle. For the second period, which is less well defined, the incertitude is in the hundredths. For more than a century we have careful records of spot numbers which reappear regularly. Now, in the course of a century the difference of eight REACTION OF PLANETS UPON SUN—PUISEUX. 165 months between the periods brings them from complete coincidence to an absolute discordance. What now remains of our hoped-for proof if the nearest approach of the planet must sometimes condition an increase of spots, sometimes their disappearance? We may suppose that Jupiter’s action, though preponderant, is modified by a somewhat slower disturbing force which increases the interval between successive maxima. But the statistics of the num- ber and extent of the spots, analyzed with the view of finding such a force, assigns to it such a long period that we have no clue as to its origin. A priori the most probable disturbing body would seem to be Saturn. It must act in the same sense as Jupiter, although to less extent. The spot maxima or minima should be particularly pro- nounced when the two planets are in conjunction with the sun—that is, every 20 years. Here again the evidence is negative. We get an even less favorable answer from the rest of the planets. Hither their, revolution periods are too short to render an account of an 11-year fluctuation or their distances too great for their action to be sensible compared with that of Jupiter. THE PLANETS AS A DISTURBING ELEMENT IN THE SOLAR CYCLE. No planet, then, or combination of planets seems to be the princi- pal cause of the solar cycle. We may, however, suppose that this or that planet may for a brief time trouble the cycle by rendering the distribution of spots irregular in longitude. The sun rotates with reference to the fixed stars once in 25 days. The planets revolve about it in the same direction, but more slowly. Therefore, to an observer on the sun, the successive passages of a planet over his meridian occur in periods somewhat longer than 25 days, tending to approach this (sideral revolution) as the planet’s distance increases. This is called the synodical rotation. That cor- responding to the transit of the earth is 27.35 days. Considering now the extreme mobility of the solar surface, we will see whether each planet does not produce a tidal wave which passes over the sun’s surface with the corresponding synodical rotation period and capable of producing visible disturbances. According to the elementary law of Newton, the relative impor- tance of the tidal waves for the various planets is given by what we may call the deforming factor, the product of the mass by the inverse cube of the distance. If we make the value of this factor unity for the earth, the mean values for the planets are as follows: oe STENT ly UE LN Ere ae 1.04 | J upiter Bs Ws ot a 2. 20 RSet ee ree Seo Satyr ws) lee een . 106 Fs Ui olla STL i ge A aa TEOO | MUTATE A a 7S ts . 019 ES ONC aoe ee Eee HOS) PaNemtune tec se) at be et, . 001 166 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. We see that the most active cause for a tidal wave lies in Jupiter, followed closely by Venus. Mercury and the earth come next, the remaining planets being much less active. Although the earth comes only in the fourth rank, we will con- sider it first because we are better situated for examining its effects. At each instant we can consider the sun as divided into two equal hemispheres, one visible, the other not. The limiting meridians turn uniformly over the surface of the sun in 27.35 days, the synodical period. Let us first suppose that the earth has no physical influence on the development of the spots. The ratio between the total sun-spot areas in the two hemispheres may happen to have any value what- ever; but the mean value taken over a long period of time embrac- ing many synodical rotations, say for a whole solar-spot cycle, should differ very little from unity. We can not at any given moment count or measure the spots on the invisible hemisphere. But we can count the spots which appear on the eastern border and compare these with those which disap- pear in the corresponding time limit at the western border. The ratio of the two numbers would have a tendency to surpass unity if it is at a time of decrease in spots and to be less than unity if in the in- creasing phase. But taken over a whole cycle, the mean value should differ very little from unity. Now, let us suppose that the earth does have a physical influence, for instance, to fix our attention, that the presence of the earth above the horizon of some point on the sun favors the development of a spot at that point. As this development is certainly not instanta- neous, any more than is its disappearance, more spots will be born in the visible hemisphere than in the opposite one. Consequently, more spots will disappear over the western border than appear at the eastern. The inverse inequality will be observed, provided we observe over a sufficiently long period, if the presence of the earth causes the disappearance of spots. Instead of comparing the eastern with the western border we could compare the two halves of the visible disk, the right with the left, and the result would be equally decisive. Practically, if the action of the earth on the solar surface is real, the action will necessarily take a certain time to become manifest. Considerable masses must be moved, masses doubtless subject to interior friction. It is so rela- tive to terrestrial tides which at any point of the earth suffer a variable retardation, but always very marked with reference to the passage of the moon over the meridian. If the earth has no influence, the two halves—the right and left—would, if considered over a sufii- cient time, show the same number and same area of spots. If the earth has a real influence there will be found a persistent and sys- tematic mequality. REACTION OF PLANETS UPON SUN—PUISEUX. 167 RESEARCHES OF MRS. MAUNDER, 1907. Mrs. Maunder undertook to answer this question, utilizing the photographs due to a cooperation of English observatories for the interval 1889 to 1901, extending from one spot minimum to the next. At the beginning and the end the sun seemed absolutely free from spots. In every instance the rare survivors which could be found at the beginning and the end of the period upon the visible hemisphere could not vitiate the conclusions derived from all the observations. The tables obtained at Greenwich comprised— (1) The positions and areas of the groups for each day. (2) The history, day by day, of each important group; the areas are expressed in millionths of the visible hemisphere and are cor- rected for the effect of perspective; the mean duration of a group is about six days; 2,870 groups were studied. Mrs. Maunder divided the visible hemisphere at each instant into 14 vertical zones, each 13.2° wide and numbered in the inverse order of their appearance. For each zone and the entire period the sum representing the area of the spots was made. These results were com- pared for zones symmetrical to the central meridian. There was thus made manifest a systematic variation from two points of view: (1) Despite the perspective correction, there was a constant pro- gression on each side in passing from the limb to the central zone, as if the perspective correction had been insufficient. (2) For each pair of zones there was a constant decrease in passing from the eastern to the corresponding western zone. The same thing was noted when in a similar manner the northern and southern hem- ispheres were treated separately. Various reasons make the measures on the extreme zones less trust- worthy, but even if we omit them the same conclusions result. If refraction in the solar atmosphere plays a part it would unduly en- rich the extreme zones. Accordingly, if a correction is made for it, it but increases the first anomaly. Neither anomaly can be due to errors of observation or reduction. If we do not like this process of treatment we need not depend upon the areas of the spots but count simply the number of groups visible in each zone, omitting those of long life which necessarily appear in both halves. Here again, for all pairs of zones, the eastern one shows a greater number than its corresponding western one. We next ask whether there is, either in the visible or in the invis- ible half, an habitual and systematic excess in the number of spot births over deaths. A priori, it seems as if it must be so for one or the other hemisphere during the phase of increasing spots, but that an equilibrium must be established when a complete cycle is con- sidered. a) ae 168 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. To throw light on this point Mrs. Maunder associated on each half of the disk the two extreme zones and compared the number of groups of spots which had been seen in each of the two double zones. The predominance was clearly in the eastern pair. There are throughout a cycle more spots seen near the eastern border, and consequently for the whole visible hemisphere and whole cycle there is an excess of disappearances over appearances of spots. The oppo- site must hold on the invisible hemisphere, since at the beginning and end of a cycle the sun is entirely free from spots. Neglecting the extreme zones, where the disappearances may be more subject to error, there was obtained for each zone the number of spots which were seen in it for the first time and the number seen in it for the last time. The following result was noted: As we go from east to west, crossing the visible hemisphere, there is an almost constant diminution in the number of spot appearances over a whole spot cycle and as nearly constant and even greater aug- mentation in the number of disappearances. When we compare two symmetrical regions of the disk, the number of births found in one is generally smaller than the number of dis- appearances in the corresponding region on the other side of the cen- tral meridian. If we were dealing only with numbers, the departures noted might be considered as resulting from a psychological cause. It is probable that there is in an observer a certain, perhaps unconscious, laziness which keeps him from recording new appearances and prolonging old spots unless absolutely necessary. It is always more agreeable to register a disappearance which simplifies work rather an appear- ance which augments it. Thus, when a new small spot appears for the first time, there is a tendency to include it among those already noted rather than to regard it as an advance guard or germ of a new group. If the first impression is wrong, then there results an unjustified diminution of births in the visible hemisphere. In a similar manner, if a small group approaches a more important group, either by expansion or derivation, there will be a tendency not to consider it separately and to cease counting it as soon as the separation between it and the larger group ceases to be distinct. We are thus led to credit fictitious disappearances to the visible hemi- sphere. Both these considerations lead us to record more disappearances than births. But these errors in counting do not explain why the total area of spots is regularly found greater in the eastern half of the visible disk. Considering all of Mrs. Maunder’s results we are led to think that the presence of the earth above the horizon of a place on the sun tends to make spots there disappear. REACTION OF PLANETS UPON SUN—PUISEUX. 169 CHECK METHODS. This result is in a way too beautiful. We had hoped to find only a small influence and we find one so decided that there is little room left for the other planets. Accordingly, search has been justly made for other proofs. We may, for instance, compare— (1) Only the areas, in the east and west halves, of the groups of long life which have been completely followed across the disk. Here, again, without exception, for all symmetrical pairs of zones, the ad- vantage remains with the eastern half of the disk. (2) We may retain only the groups of long life seen in more than two successive rotations, neglecting the first and last appearances, keeping only the intermediate appearances. It is evident that in this way no appearance can be omitted or fictitious disappearance be registered. Despite these safeguards, the eastern portion still re- tains its advantage in the proportion of 19 parts in 100. (3) We may substitute for the spot statistics those obtained from the protuberances observed on the east and west limbs and see if the protuberances show the same inequalities in activity as do the spots at the limb zones. The protuberances, we have seen, follow more or less closely the solar cycle in their development. But the method of observation for the protuberances is quite different than for the spots. Mrs. Maunder found no sufficiently complete and homogeneous series of observations of the protuberances for the interval 1889 to 1901, which her spot statistics covered. The studies of Ricco at Catania, however, cover well the interval between the last two spot maxima. Diagrams made from this data show that from 1892 to 1900, during the decrease in spot numbers, the eastern limb had on the average more protuber- ances than the western limb. The opposite condition held from 1900 to 1904, but after the spot maximum was reached in 1905 the eastern limb again regained its ascendancy. On the average, the eastern limb maintained a superiority of 1 to 20, less constant and less marked than in the case of the spots, but in the same sense. Deslandres has recently pointed out a circumstance which may ren- der the protuberances more easily visible on the east than on the west border. The sun, which we have reason to believe is electrified at its surface, must by its rotation create a magnetic field. The very mobile protuberances would be disturbed by this field so as to be bent at their upper part in the direction of the rotation. An observer would then not be in an impartial position relative to the two limbs of the sun. He will see better the oncoming protuberances which would be bent toward him than the disappearing ones which would be bent away. This hypothesis seems to be confirmed by the deforma- tions and velocities of the protuberances. 170 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. A similar explanation is not so easy in the case of the spots. In order that they may be more easily visible on the eastern than on the western limb, we may suppose that they are followed, but not preceded, in their general rotation by some kind of a cloud. Each spot would then have its cloud, allowing the spot to be seen as it approached but hid more and more as it departed. This explanation is not very convincing. In order that the cloud have an appreciable effect upon a great spot it would have to be at quite an elevation, and it is difficult to see how it would escape observation at the border of the sun. Its influence would not be felt except toward the ends of the spot’s transit, and we have seen that the inequalities are noted in the same sense in all pairs of sym- metrical zones. (4) There remains one more test which we must not neglect. We could not pretend that the earth alone has such an influence upon the sun. If it is effective, then the other planets must be; and there are apparently three, Jupiter, Mercury, and Venus, which should be even more effective. How can we assure ourselves in this matter ? RESEARCHES OF THE KEW OBSERVERS. The problem had already been attacked long ago by De la Rue, Balfour Stewart, Benjamin Loewy, astronomers at the Kew Observa- tory. (Proc. Roy. Soc., p. 210, 1872.) As the observations never related to but a half of the sun at a time, it was considered neces- sary at the start to determine and try to eliminate the influence which the position of the observer on the earth might have. The two following conclusions resulted from the preliminary examination: (az) Upon the hemisphere visible from the earth the mean area occupied by the spots increases as the distance on either side of the central meridian increases. (6) The spotted surface on the average is greater on the western than on the eastern half of the visible disk. The second conclusion of the Kew observers is at variance with that of the more recent investigators. However, the years examined in the two cases have no part in common. The data used by Mrs. Maunder was so much more homogeneous and abundant that her conclusions should have greater weight. Having completed their first examination, the Kew observers con- sidered how to correct their data for the position of the observer. They could then, for any planet whatever, P, compare the hemisphere turned toward the planet P with that turned away. Relative to the circle limiting these two hemispheres, any other planet, P’, could have any possible position in its orbit. It seemed right to admit that, if the interval considered be long enough, the effect of P’ would ge oe ee ee, REACTION OF PLANETS UPON SUN—PUISEUX, 17 La my be eliminated and the effect of P would become evident by comparing the conditions on the two hemispheres. It was found thus that the spotted areas tend to increase opposite to Mercury and Venus. Jupiter, upon which the greatest hope was placed, gave no definite result. The work of the Kew observers has been rather severely criticized. The interval used seems too short for assuring the proper compensa- tions, and the gaps in the data are considerable. The choice of the material selected has not always seemed justified. ; RESEARCHES OF SCHUSTER. In a recent memoir (Proc. Roy. Soc. 85A, p. 309, 1911) A. Schuster considered it advisable again to take up this problem, using the Greenwich photographs for the years 1874 to 1909. He considered only the births of spots lasting over the interval between the plates of two successive days. He excluded, as more subject to error, those births which, seen from the earth, appeared at less than 30° of lon- gitude from the eastern border. There remained 4,271 spots to consider. For each planet P, the sun was divided into 12 equivalent vertical zones. The solar meridian passing through the planet P formed the boundary between the zones 6 and 7 on the hemisphere toward the planet and between 12 and 1 on the farther side. The number of spots seen for the first time in each zone was counted and used to form a plot having as abscissee the zone numbers. The results are rather irregular especially if—as Schuster did at first—we consider separately the spots counted when the earth is east or west of the central meridian. Of the three planets—Mercury, Jupiter, or Venus—each one seems to produce a minimum of spots where another may produce a maximum. If the above distinction is not made, the results seem more concordant. For all there is a minimum upon zone 38, that is when the planet is just rising, and a maximum on zone 8, which has already passed the meridian. This can be compared with the diurnal march of temperature on the earth due to the influence of the sun’s heat. But there are other intermediate maxima and minima for which the three planets are in no ways in accord. Schuster, however, considers that the similarity of march of the three curves for divisions 3 and 8 is sufficiently characteristic for rendering very probable the reality of a planetary influence. This march is very different from that which had been found for the earth and much less definite. The effective activity of the earth is therefore apparently of another nature and relatively stronger, or it is only apparent and due to the situation of the observer. 72 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. The question was next taken up whether the distribution of spots in longitude did not become more unequal when the three planets considered, or two of them, were in conjunction for the same solar zone. The plots were remade considering only the spots born when that condition was fulfilled. No marked difference was evident. It seems as if the number of spots appearing in a zone is greater only when one of the planets in the conjunction, or slightly past it, is Venus. Schuster thinks that a planet may have merely an exciting action, effective only in putting into play a force already existing in the sun. Accordingly, a second planet on conjunction might not have any additional effect. RESEARCHES OF F. J. M. STRATTON. Stratton (Monthly Notices, 72, p. 9,1911) thought that it would be worth while to again take up this research, considering the disap- pearances as well as the appearances, and retaining only those which occur at less than 50 degrees from the solar meridian passing through the earth. He considers only Jupiter and Venus, which seemed the most probable as having an influence on the spottedness. The period used was the one of 36 years, 1874 to 1909, for which the photographs of the Greenwich Observatory furnished a complete series. The surface of the sun was divided into 24 equal zones instead of the 12 which Schuster used. The origin was the meridian passing through the planet at the moment of birth or disappearance of a spot. The zones 0 to 6 corresponded to meridians which had already passed over the planet but which are now hid from it. The zones 18 to 24 corresponded to meridians which are to transit but which are still out of sight. He then constructed for each planet plots in which the abscissee were the zone numbers and the ordinates— (a) The number of spots seen for the first time in each zone. (6) The number of spots seen for the first time in the northern part of each zone. (c) The number of spots seen for the first time in the southern part of each zone. | (dq) The number of ephemeral (that is, seen for one day only) spots seen in each zone. (e) Total number of spots seen either for the first time or for one day only in each zone. This gave five curves for each planet. These were remade, using the spots seen for the last time instead of those seen for the first time; that is, disappearances instead of appearances. REACTION OF PLANETS UPON SUN—PUISEUX. 1730 - The plots were very irregular. Generally there was no similarity in their contour, even for the same planet, between the two hemi- spheres; neither was there between the same homispheres for differ- ent planets. There is one single coincidence, perhaps, which seems not due to chance. There is a maximum of ephemeral spots noted in the zones the meridians of which either Jupiter or Venus had already passed three hours previously. It is notable that for this interval of 36 years a terrestrial ob- server always notes in the central region of the sun more disap- pearances than appearances. The difference reaches 10 parts per 100. This agrees with what Mrs. Maunder found for the interval 1889 to 1901. For Jupiter and Venus the births seem more frequent when the planet is above than when under the horizon; that is, in the opposite sense from what Mrs. Maunder found for the earth. But the difference is very small and merits no physical explanation. The relation between the east and west hemispheres of the sun, as seen from a planet, is for Venus in the opposite sense than is the ease for the earth. In the case of Jupiter there is scarcely any dif- ference, as the following table shows: Spots seen on the hemisphere of the sun toward a planet. East half. | West half, ODSHIEETR oo j2 18 oS en ee ET SPE 8, 792 8.711 LE AND < oro e done! bbpehUSOSeeee e ae eee ee a SE ei poe epee veo pen 8,213 7,508 Ses Entre eh in a 88 SiMloiniciqa kh Pooh ep kgcisenee aiseueolae | 7,834 8,368 Another comparison may throw some light on the matter. When a planet is on a given side of the equator is the hemisphere on the same side as the planet especially favored with spots? The reply is contained in the following table: South, number of | North, number of spots. spots. Planet. South. North. | South. North. ee eee | 8,419] 5,621] 5,785 5,931 Joule. 4) 380s ee ee ae ne eae 1,512 1,254 1,485 1,329 (ORDME ofa Sa So they SU eA a 6,931 5, 750 7,381 6, 212 This table seems significant if only the left half is considered. But the preponderance in the southern hemisphere continues whether the planet is to the south or to the north. That is, in the interval con- sidered, the southern hemisphere of the sun had habitually more spots. This may be due to causes within the sun and to no influences from the planets. @iu ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. This simple comparison leads us to suspect that the concordances noted in the plots for the various planets may be due to causes within the sun, There are two possible reasons for the inequalities in the plots: (a) Any given zone relative to the planet can remain invisible from the earth for months. (b) The epoch when a particular planetary zone may be favor- ably seen by a terrestrial observer may fall sometimes in the spot maximum phase, sometimes in the minimum phase. The second perturbing effect is graver than the first. The period of 36 years embraced by the Greenwich data is not sufficiently long to assure us that these two sources of error are eliminated. The method should not be abandoned, but we must get more observations. CONCLUSIONS. It would be presumptious to say that we have unveiled the mode in which the planets may react upon the sun, but we feel persuaded that some reaction exists and that it will not always elude us. The sun may have within itself the reason for its period, but it does not keep to itself its rythmic action. If it has not sufficient store of energy in the mutual attraction of its parts, in its rotation or in the active force of the plants, there remains a resource in the cosmic dust. Perhaps it is not the matter condensed into the shining stars but that which is scattered in impalpable particles throughout space which contributes more to the stability of the universe. It seems to me that these views suggested by the study of the heavens help to keep us even in every-day life from discouragement and indifference. The historian, whose attention is focused on salient events, may believe that the human race exists only for a few marked men. The naturalist, accustomed to note the annihilation of the weak, cries willingly with the poet, “ Le vent n’ecoute pas gemir la feuille morte” (The wind hears not the sigh of the lifeless leaf). But that is only apparently true. The dead leaf, in its manner and measure, reacts on the wind, Already religious moralists warn us that every act, no matter how small and weak, has a sovereign value when it is done in conformity with the eternal order. And this conclusion will not surprise the geometrician, who is constrained to weigh all in an impartial balance and recognizes in the smallest corner of the universe an unlimited influence with regard to space and the future. RECENT PROGRESS IN ASTROPHYSICS. By C. G. ABBOT. [ With 38 plates. ] According to the definition of the word by the late Prof. Newcomb in the last edition of the Encyclopedia Britannica, “Astrophysics is that branch of astronomical science which treats of the physical constitution of the heavenly bodies.” Interpreting this definition in a manner somewhat narrower than that which is generally accepted in astronomical circles, Prof. Newcomb, in his article on astrophysics, mentioned the principal conclusions of the science to be that the heavenly bodies are composed of like matter with that which we find to make up our globe; that as a rule the incandescent heavenly bodies are mainly composed of gas, or of substances gaseous in their nature; and that the temperature of the great heavenly bodies is extremely high. He thus omitted from the province of astrophysics the study of the motions of the celestial objects and their parts by aid of the spectroscope, although this certainly has a bearing on the physical constitution of these objects. Information of fundamental importance in relation to the nature of the heavenly bodies and the evolution of the universe has resulted from investigations of the radial velocity of stars by the spectroscope; and this is supplemented and confirmed by observations with the telescope alone. Hence I shall not confine myself strictly in what follows to Prof. Newcomb’s definition of astrophysics, but shall include the discussion of several subjects which have at least an astrophysical bearing, though not strictly, perhaps, astrophysical in themselves. THE WAVE LENGTHS OF LIGHT. All modern spectroscopic progress depends upon the exact knowl- edge of the wave lengths of the lines of absorption or emission of the chemical elements. Long ago it was discovered that sodium and its compounls, when heated to incandescense, gave out a yellow light, which when examined by the spectroscope, resolved itself into two lines of wave lengths 5,890 and 5,896 Angstrém units. It was also found that when sodium vapor was interposed between a source of white light, like the electric arc, and the slit of the spectroscope, there would be found in the place of the bright yellow lines of sodium 175 ee 176 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. two dark lines of absorption, where light of the are spectrum was taken away. Similarly, in the spectrum of iron, a great number of | bright lines are found in the green; and if iron vapor is interposed — between an electric arc light and the slit of the spectroscope, a great number of absorption lines will be found at the corresponding places. Also in the spectra of the sun and of many of the stars there occur dark lines corresponding exactly in place to the bright lines of the spectra of the chemical elements found upon the earth’s surface. From these indications it is clear that these chemical elements exist as vapors in the substance of the sun and stars. The number of chemical elements in the sun and stars is so considerable and the num- ber of their spectrum lines is so great, that the solar and stellar spectra are thronged with dark lines, so that it takes the most exact knowledge of the positions of the lines to insure for them a correct interpretation. But in recent years a great deal more has been learned by the aid of the spectroscope in regard to the sun and stars than of their mere con- stitution, for it is found that although the spectrum lines occur almost exactly in the same position in the spectra of the heavenly bodies that they do in the spectra of the laboratory, yet there are slight and very significant deviations of position which are attributable to the motion of the heavenly bodies to or from the earth. For, just as in the whistle of a locomotive, there is a sharping or flatting of the pitch, depending upon whether the locomotive is coming toward the ob- server or going away from him, so in the light of the stars there is a displacement of the spectrum lines toward the violet or toward the red, according as the star is approaching toward or receding from the earth. One may go even farther, and say that there is a difference in the position of the spectrum lines of the sun according as we take the light from one edge of the sun or the other. For one edge is ap- proaching the earth by virtue of the rotation of the sun while the other is receding. It is also shown that the position of the spectrum lines depends upon the pressure of the gases in which they are pro- duced, so that it is possible to determine by exact measurements the pressures under which the gases lie in the sun and stars, although these are so extraordinarily remote that it takes light minutes or years to reach the earth from them. Finally, it has been shown by Zeeman that the form of the spectrum lines of the chemical elements differs according to whether the light is produced in a magnetic field or not. Accordingly it is possible to determine from measurements of the solar spectrum whether magnetic fields exist in the sun, and, if so, to what intensity they rise. All these kinds of measurement, which depend upon extremely slight displacements of the spectrum lines, evidently require that great accuracy shall be obtained in the determinations of the positions PROGRESS IN ASTROPHYSICS—-ABBOT, WE of these lines in the laboratory. When about the year 1895 Rowland completed his investigation of the spectrum of the sun and of the chemical elements, it was thought that the last word had been said upon this, and that no greater accuracy of positions of the spectrum lines was necessary, or indeed possible, than he had obtained. But in recent years it has been found necessary to go over the whole ground again, and to determine the positions of the lines of the chemical elements and the lines in the spectrum of the sun with a still greater accuracy than that of Rowland. This work has been taken up under the auspices of the International Solar Union, and is now approaching a satisfactory completion. In the year 1893 a remarkable piece of work was carried out by Prof. Michelson (now of the University of Chicago) in the measure- ment of the wave length of light in terms of the standard meter of the International Bureau of Weights and Measures at Paris. Several of the spectrum lines were investigated, and among them the red line of cadmium, whose wave length as determined by Michelson is 6438.4722 Angstrém units. In pursuance of the investigations re- cently recommended by the International Solar Union, Messrs. Fabry and Perot remeasured the wave length of the cadmium line and found the value 6438.4696, which, it will be seen, differs by less than 3 parts in 6,000,000 from that obtained by Michelson. On this value of Fabry and Perot will rest the system of wave lengths adopted by the International Solar Union. It had been determined at the meeting of the Union on Mount Wilson in 1910 that only wave lengths which are independently de- termined with satisfactory agreement by three observers with the most approved apparatus should be accepted as secondary wave- length standards. In pursuance of this action of the Solar Union, Messrs. Fabry and Buisson in France, Pfund at Baltimore, Eversheim and Burns in Germany, have been determining with the highest possible accuracy the wave lengths of certain lines in the spectra of iron and nickel, selected at nearly equal intervals of wave length. About 85 such lines have now been measured with satisfactory agree- ment in three or more independent investigations, and have been adopted by the International Solar Union as secondary standards of wave length. These lines cover the spectrum from a wave length 3370.789 Angstrom units, which is far beyond the visible limit of the spectrum in the violet, to wave length 6750.163 Angstrém units, which is near the limit of the visible red. It is expected that further investigations will carry the lists of secondary standards as far as wave length 2,000 in the ultra-violet, and perhaps as far as wave length 10,000 in the infrared. The astonishing accuracy of the re- sults obtained may be inferred when it is said that the three inde- 1The Angstrém unit is one ten-billionth of a meter. 44863°—sm 1918 12 ft 178 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. pendent investigations generally agree to the seventh place of spit cant figures. Also St. John and Ware have investigated the con- sistency of the standards, each to each, by determining other wave lengths independently by interpolation from several different stand- ards, and are of the opinion that adjustments in the seventh place of significant figures are hardly ever necessary, and will perhaps never exceed 0.002 Angstrém units in any case. Investigations are now on foot by St. John and Ware, Goos, Burns, and others to determine a large number of tertiary standards of wave lengths intermediate between these secondary standards, and it is hoped that good agree- ment in regard to the tertiary standards will soon be obtained. It is found necessary in this work to specify the strength of the electric current, the length of its arc, and the position of the sht of the spectroscope with respect to the arc in order to get satisfactory results. It now remains to go over the whole system of spectra of all the chemical elements and determine the positions of their lines with respect to these standard lines of iron, nickel, and barium which have been adopted, and further to go over the whole solar spectrum and to determine the position of its absorption lines with respect to these standards. Although this will involve an enormous amount of careful work in photography of the spectrum and in the measurements of the re- sults, a work which will be so exacting as to appear at times almost a drudgery to those who are engaged in it, yet like other good work it is almost beyond question that it will yield unexpected fruits of discovery in addition to those of investigations of the nature of the sun and of the stars for which it is primarily undertaken. SOLAR PROBLEMS. 1. THE NATURE OF SUN SPOTS. Soon after the invention of the telescope, Galileo, in the year 1610, observed spots on the sun. They continued to be observed by many persons, and in the middle of the nineteenth century it was found by Schwabe that the appearance of them was periodic. The average interval between successive maxima or minima of sun spots is 11 years, but individual periods range from 8 years to 15 years in length. The years from 1905 to 1910 were distinguished for large numbers of sun spots, and the years 1910 to the present time for very small numbers. We are now probably just at the beginning of a new sun- spot maximum period, so that the report of spots being seen upon the surface of the sun need not surprise us. Sun spots, as seen in the _telescope, consist of a dark central part called the umbra, and a less dark shading around it called the penumbra. The appearance of the sun when large spots are upon its surface is shown in the accom- panying figure (pl. 1). BS — as Smithsonian Report, 1913.—Abbot. PLATE 1. SOLAR PHOTOGRAPH SHOWING SUN SPOTS. Taken from the Astrophysical Journal, volume 82, plate 1, figure 1, article of Slocum, page 24, 1910. ‘01g oSvd ‘27 o3R[d §(op 3: uoJoTddy “a ‘L6T GusAAdoD) NS 95, S40 ULOAf UOARL *AYOLVAUSSAO YVIOS NOSTIM LNNOWW AB dV) WNYLOadS LOdS-NNS | fe A ba | MyITTT fe hdtuber lian 06 ohs} a 09 0S OV O€ 02g nO) aLV1d ‘Loqqyv—'¢ 161 ‘uoday ueluosy}ILUS PROGRESS IN ASTROPHYSICS—ABBOT. 179 The nature of sun spots has long been a subject of investigation. In the last few years comparatively satisfactory conclusions have been drawn. It appears that sun spots are cooler than the surround- ing surface of the sun. This is shown in several ways. In the first place, a delicate electrical thermometer, called the bolometer, in the hands of Langley and subsequent investigators, has shown a de- creased temperature when exposed to the rays from sun spots, as compared with its temperature when exposed to the rays of the sur- face of the sun close by. In the second place, the spectrum of the sun spot is found to differ from the spectrum of the solar surface in the immediate neighborhood in certain very characteristic ways. This difference has been investigated by the Mount Wilson Solar Observatory. A photographic map of the sun-spot spectrum as com- pared with the spectrum of the sun’s surface has been published by that observatory. The accompanying illustration (pl. 2) is taken from an interesting portion of such a spectrum map. It shows in the first place that a large number of lines are found in the sun-spot spectrum which are either very indistinct, or not to be seen at all in the spectrum of the sun’s surface. It shows in the second place that certain lines are broadened, or made double, in the spectrum of the sun spot as compared with the spectrum of the sur- roundings. In the third place, that some lines are weakened and some strengthened in sun spots, as compared with those of the sur- roundings. The cause of the numerous additional lines in the sun- spot spectrum has been found to be the presence of certain compound substances, such as calcium hydride, magnesium hydride, and certain oxides, as, for example, that of titanium. The cause of the different intensity of certain lines in the spectra of the spot and of the sur- roundings is shown by Hale, Adams, and Gale to be the decreased temperature of the sun spot. This conclusion they confirm, line for line, by noting the behavior of the lines of the corresponding chemi- eal elements when observed at different temperatures, by the aid of the spectroscope, in the laboratory. The doubling or widening of the lines of the sun-spot spectrum was found by Hale to be due to the presence in sun spots of a magnetic field. This observation depends on the discovery of Zeeman that the spectrum lines of the chemical elements, when produced in a strong magnetic field, are often doubled or trebled or made even more com- plex. The component lines, so produced, depend as regards their position, number, and the polarization of their light, upon the strength and direction of the magnetic field through which they are observed. The relation of magnetization to the polarization of the light was the feature of the matter which laid the subject of. the widening of lines in sun spots open to Hale’s investigation. By the use of proper apparatus for the polarizing and analyzing of light, 180 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. he was able to remove or alter the individual components of the spectrum lines in a manner adapted to show the magnetic field exist- ing in the sun spots where the light was produced. This most inter- esting discovery he has now pushed still further, and has examined the magnetic field of the whole surface of the sun. He finds that there exists upon the sun a magnetic field similar in many of its char- acteristics to that which exists in the earth, although the intensity of the field is so extremely slight that the shifts or alterations of spec- trum lines caused by it are almost beyond the possibility of disclosure. Recently it was shown by Evershed that in the penumbras or dark- ened edges of sun spots, there are found shiftings of the spectrum lines which show that the vapors are moving outward from the center of the spot, or umbra, toward the outlying parts of the penum- bra. Later investigation shows that this outflow of the gases from the umbra toward the outer part of the penumbra is accompanied by a motion of rotation also around the umbra, so that the motion resolves itself into a whirling of these vapors or gases similar to that which is found in a waterspout. This has a very important bearing on the explanation of the magnetic field in sun spots dis- covered by Hale, for it was shown by Rowland many years ago that an electric charge in motion has the property of an electric current of producing a magnetic field. Thus if there are in sun spots materials under dissimilar electric conditions, and these materials be whirled as in a waterspout, they must necessarily produce a magnetic field. St. John, of the Mount Wilson Solar Observatory, has made a thor- ough investigation of the motions of the vapors in the neighborhood of sun spots, using the spectrum lines of many of the chemical ele- ments. He finds that the displacements of the spectrum lines of iron and some other well-known metals indicates a motion away from the umbra. The motion, on the other hand, of magnesium and hydrogen and some other of the lighter chemical elements is toward the umbra. Is was also shown some years ago in a photograph by St. John that hydrogen gas is sometimes sucked into the center of a sun spot. All these various lines of evidence indicate that a sun spot is a whirl in the gases of the outer part of the sun, analagous to a water- spout, and that this whirl comes from within outward. Associated with the whirl there is produced a magnetic field, and associated with the outward motion of the materials a decrease of pressure. The decreased pressure of the gases causes their expansion and conse- quent cooling, so that the coolness of the sun spot is thereby ex- plained. As the gases spread out at the surface of the sun, the lighter gases—hydrogen and others—which are found in the outer- most solar layers, are sucked into the partial vacuum at the center of the whirl. PROGRESS IN ASTROPHYSICS—ABBOT., 181 2. SOUNDING THE SOLAR DEPTHS. St. John’s investigations of radial motion in the neighborhood of sun spots have led him to further very interesting results. For it appears that if one takes the various lines of iron as found in the Pressure Elevation Z in atm's in km, a HG KS 0.0 25000 SS Ha 7 pate $< HK 4 13.000 1 ee \ “ i or ! eg | | ui S 275) 5) e i Trew A Ho us Chromosph€ére 4000 \ / wv / / Le, Ca eet / a ty Le, pie pies oi 15- 20° Fe (15-40) eel (of velocity - inversion ~~ ig oes ia if 1 > MeO a a rH if % 7 a wa 2 eg i n 10 Fe Bae Reversing layer ! N a il! “ee Ve Sx ge 3000 ll TEES Fe Py I fom Fe aN 0.5 Mp4 > Fe -” Ni se 30 800 wl 4 (ee as \ De i, | 3—-—H———_——__+> Fe \ os 57 Si pe ea as a Fe Siege 250 2 Fic. 1.—Vertical section of reversing layer and chromosphere, showing distribution of radial velocities of sun spots. The lengths of solid lines are proportional to radial displacements of the corresponding Fraunhofer lines. Arrows indicate direction of flow. The rounded head of the cyclonic disturbance is suggested by the broken-line curve enveloping the outward velocities. Broken iines with arrows refer to possible velocities below the accessible levels. Lines of force of the magnetic field are indicated in the usual way.—From Report on Mount Wilson Solar Observatory, by George E. Hale, Twelfth Year Book Carnegie Institution of Washington, 1913. sun’s spectrum, classifying them according to their faintness after the manner of Rowland, the fainter lines show greater displacements and thereby more rapid outflowing in the sun-spot whirls than do the brighter ones. In fact, the brightest iron lines show less than a 182 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, fourth as great displacements as do the fainter ones. Now, it appears from various lines of reasoning that the fainter lines should be the ones that are formed at the greatest depths, so that St. John is able to arrange the iron spectrum with reference to faintness and with reference to velocity of outflow in sun spots in a series which very probably indicates a progressive depth of sounding below the sur- face of the sun. Then corresponding to this iron scale, if he takes the lines of the other chemical elements, comparing them line by line as regards velocity of outflow with the velocity shown by his iron scale, he may arrange all the chemical elements in terms of the iron scale, in the order of their depths of occurrence below the sun’s surface. In this way he finds, as is indeed indicated by other lines of re- search, that the heavy chemical elements will he the lowest, and vice versa. Corresponding to this arrangement it is natural to find that the lines of calcium, sodium, magnesium, and hydrogen indicate a flow of greater and greater velocity in the opposite direction from those of iron, so that these elements are arranged above the upper- most level of the iron lines in a progress outward from the general solar surface. Thus, as shown in figure 1, we may have the arrange- ment of the vapors as they exist in the sun, from the hydrogen at the highest level down to the elements like lead, lanthanum, barium, at relatively low levels. Such elements as uranium (and radium, if it exists in the sun) are so very high in atomic weight that they lie very deep down in the sun and do not give solar-spectrum lines at all, so that we shall probably not obtain direct proof of the ex- istence of radium in the sun on account of the low level at which it must lie if present there. We have, to be sure, long known of the existence in the sun of helium, which is a product of the disins tegration of radium. This may, perhaps, indicate that the parent substance, radium, is also present in the sun, but of this there is no certainty. 3. MEASUREMENTS OF SOLAR RADIATION In the Smithsonian Report for 1912 the writer gave an illustrated account of the investigations of solar radiation by the Astrophysical Observatory of the Smithsonian Institution. In July, 1913, the results of this long investigation were published with details in volume 3 of the Annals of the Astrophysical Observatory. The most important conclusions are as follows: 1. The mean value of the solar constant of radiation for the epoch 1905-1912 is 1.932 calories per square centimeter per minute. 2. An increase of 0.07 calory per square centimeter per minute in the “solar constant” accompanies an increase of 100 sun-spot numbers. 3. An irregular variation frequently ranging over 0.07 calory per square centimeter per minute within an interval of 10 days is PROGRESS IN ASTROPHYSICS—ABBOT. 183 established by numerous nearly simultaneous measurements at Mount Wilson, Cal., and Bassour, Algeria. 4, Indications of two wholly independent kinds incline us to think that these variations of solar radiation are caused within the sun, and not by iuterposing meteoric or other matter. STELLAR PROBLEMS. I. THE DISTANCES OF THE STARS. The actual distances of several hundred of the stars can be said to be known within moderate limits of accuracy. Various methods are used for determining the distances of the stars, but they gen- erally depend upon the fact that the earth, by reason of its revolu- tion about the sun, occupies places separated by 186,000,000 miles at intervals six months apart. This corresponds to the surveyor’s base line, and allows us to triangulate for the distances of the stars. Another method of estimating the stellar distances may be based upon the fact that the solar system is approaching the constellation Hercules at the rate of about 20 kilometers (12 miles) per second, so that the position occupied by the earth in space to-day is different from that which will be occupied to-morrow by reason of the motion of the solar system, but this method involves assumptions in regard to the motions peculiar to the stars observed. It is customary to express the distances of the stars in light-years, for the distances of the stars, if given in kilometers or miles, or even in terms of the radius of the earth’s orbit, are so enormous as to require many figures. Light, however, traveling at the rate of 186,000 miles per second, in the course of a year travels about 6,000,000,- 000,000 miles. In terms of this unit the nearest star is at a distance of four and a half light-years. The stellar distances are considered up to such enormous quantities as a thousand or more light-years. It is also customary to speak of the parallaxes of stars. By this is meant the angle which the radius of the earth’s orbit would subtend if viewed most favorably from the star in question. The parallaxes ° of the stars range from about one second of are (1’’) downward. The following table shows the relation between miles, light-years, and parallaxes of stars: Star. a Centauri. Procyon. Altair. Castor. Arcturus. Antares. tr at ut Mt ut ” Parallax. . 0.75 0.33 0. 23 0.10 0. 066 0. 02 Light-years . 4.5 10.0 14.5 33.3 50.0 166.7 Miles... ... 127,000,000 | ! 60,000,000 | 187,000,000 | 200,000,000 | 300,000,000 | 1 1,000, 000, 000 1 000,000 omitted. The first successful measurements on stellar parallaxes were made by Struve at Dorpat on the star Vega in the years 1835 to 1838, and 184 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. by Bessel on the star 61 Cygni, 1837 to 1840. Bessel’s result was 0.35’’.. This value is in close accord with recent measurements. It was a great feat to measure such a small angle as this. In modern practice the efforts to measure parallaxes absolutely have practically been discontinued, for it is found that the very faint stars are so immensely distant from us as hardly to be displaced at all in their apparent positions by the motion of the earth in its orbit. Hence, for stars which are near enough to be observed for parallax it suffices to compare their positions with respect to the faint stars in their neigh- borhoods at two epochs separated from one another by six months. Many of the parallax determinations of great weight have been made by use of the heliometer, which is a telescope with its objective lens cut in half, with the two parts movable with respect to one another by a fine screw. With this instrument the images of two celestial objects, one formed by one-half of the lens and the other by the other may be brought into coincidence by shifting the two parts of the lens with respect to one another, and the scale of the instrument gives thereby an indication of the angular distance be- tween the two objects in the heavens. Thus the relative positions of the stars may be observed for parallax purposes. Stellar parallax measurements by means of the heliometer have been the main work of the Astronomical Observatory of Yale University. A volume of the Transactions of the Observatory has been issued recently containing the results. The parallaxes of 195 stars have been ascertained with an average probable error of 0.015’’. The stars investigated at Yale naturally do not include stars visible only in the southern hemisphere. The parallaxes of some of the southern stars have been observed with the heliometer from the Observatory of the Cape of Good Hope. Of the parallaxes determined at Yale the largest pertaining to a bright star is 0.33” for the star Procyon, whose magnitude is 0.6, and which has a proper motion in the sky of 1.23’’ per century.t. According to the little table just given it will be seen that this corresponds to a distance of 10 light-years. The largest parallax found for any star by the 1The stars have long been arranged with respect to their brightness, by “ magnitudes.” A number of the brightest stars in the heavens are regarded as of the first magnitude. The Polar Star is of the second magnitude, and the brightness of the faintest of the six readily visible stars in the constellation Pleiades is 4.4 magnitudes. An increase of five magnitudes corresponds to a decrease of a hundredfold in the brightness of the stars. It was found when the measured distances of the stars were arranged in the order of the magnitudes of the stars observed that the brighter stars were on the whole nearer to us than the fainter ones. The ‘proper motion’ of a star is ordinarily given as the angle through which the star moves in a century in the heavens, after allowances are made for all effects of nutation, precession, aberration, etc., but not for the motion of the solar system toward the constellation Hercules. Proper motion therefore includes the star’s real motion in space with reference to the whole system of stars and, in addition, the star’s apparent motion, really due to the motion of the solar system toward the constellation Hercules, Proper motions tend of course to diminish the greater the distances of the stars considered. PROGRESS IN ASTROPHYSICS—-ABBOT. 185 observations at Yale was 0.39’’ for the faint star known as Lalande 21185. This star is invisible to the eye, being of magnitude 7.3 and has a proper motion of 4.77’’ per century. Another method of parallax investigation which has been devel- oped in recent years to a high state of perfection is that by photog- raphy. If a photograph of a celestial region containing the star whose parallax is to be determined is made in the earlier part of the night at one epoch, and again in the latter part of the night at an epoch six months later, the position of the parallax star will in gen- eral be found to be changed with respect to the mean position of all the fainter stars in its neighborhood. After clearing the apparent motions for the known proper motions of the stars in question, a residual effect will be left, due to the fact that the parallax star is in general nearer than the fainter stars in the background. In a method proposed by Kapteyn the photography was done in the fol- lowing manner: A plate was exposed at a certain epoch, then kept without developing for six months, exposed again in a slightly dif- ferent position, and then kept still another six months, and finally exposed a third time before developing. Thus three series of images of all the stars would be found upon the plate, of which two would be taken with the earth in one part of its orbit and the other with the earth at the opposite part. Recently Prof. Schlesinger, formerly of the Yerkes Observatory, now director of the Allegheny Observatory, has used the photographic method with the great Yerkes refractor, and has obtained parallaxes for about 25 stars of a very high order of accuracy. Prof. H. N. Russell, of Princeton, also has obtained excel- lent results by this method for 52 stars observed by himself and Hinks at Cambridge, England. These observers did not leave the plates undeveloped for a year or 18 months, according to the method proposed by Kapteyn, but preferred to take separate plates at the different epochs. This parallax work by photography is becoming extremely well thought of by astronomers, and is engaging more and more the efforts of those who have large refracting telescopes avail- able for this purpose. Tt is found, as would be expected, that in general the brightest stars are nearer the earth, and the stars whose proper motions are largest are also nearer the earth. Prof. Kapteyn published, in 1902, a formula connecting the quantities parallax, stellar magnitude, and proper motion. This is found to agree pretty well with more recent work. Prof. Lewis Boss, in his interesting discussion of the great Preliminary General Catalogue of positions and proper motions of stars, recently published by the Carnegie Institution, has also derived a formula connecting the proper motion and the parallax for stars of the 5.3 magnitude. 186 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. The positions of the stars in the heavens change slightly from year to year, owing to two causes: First, the motion of the solar sys- tem as a whole in the direction toward the constellation Hercules; second, the individual motions peculiar to stars themselves, The first-mentioned component of proper motion increases directly as the stellar distance descreases. Stellar parallax observers, being over- whelmed by the enormous number of the stars, were obliged to choose from them a small list for observation. It was natural to select stars of large proper motion for such a purpose, since these would prob- ably represent the class nearest to the earth. Hence if we take, for instance, from the list of stars whose parallax has been determined a group whose mean parallax is 0.1’’, the mean of their proper mo- tions exceeds the mean proper motion, which would be found for all the stars whose parallax is 0.1’’, if all those stars had been investi- gated. Hence it must occur that, as the distances of more and more of the stars become known, our estimated value for the mean dis- tance, corresponding to stars of a given brightness or a given proper motion must diminish. 2. MOTIONS OF THE STARS. Within the last few years great pieces of statistical investigation in relation to the stars have been published which are of the highest value for the progress of our knowledge of the universe. Americans should be particularly proud of several of these investigations. The first is by the Harvard College Observatory, under the direc- tion of Prof. E. C. Pickering. Volume 50 of its annals, containing the Revised Harvard Photometry, gives a catalogue of the positions, photometric magnitudes, and spectra of 9,110 stars, mainly of the 6.5 magnitude and brighter, covering both the northern and southern hemisphere. A still more extensive work of a similar kind, to be called the Revised Draper Catalogue, which will include data for probably 200,000 stars, is now in course of preparation at the Harvard College Observatory and may be expected to be finished within a short time, thanks to Prof. Pickering’s great eare in the arrangement of the work. The second great work to which I refer is entitled “ Preliminary General Catalogue of 6,188 stars for the epoch 1900. Prepared at the Dudley Observatory, Albany, N. Y., by Lewis Boss and pub- lished by the Department of Meridian Astrometry of the Carnegie Institution of Washington, 1910.” Prof. Boss says: “The general catalogue of 6,188 stars herein contained is the result of an attempt to deduce for these stars the most exact positions and motions that are readily attainable from the means at command.” In compiling it he has compared about 80 star catalogues, from the catalogue of Bradley, dated 1755, to modern catalogues of the period 1900. From PROGRESS IN ASTROPHYSICS—ABBOT. 187 these he has deduced the most probable positions in right ascension and declination of the stars, and the proper motions of the stars as indicated by the observations of them at long separated epochs. The result obtained with regard to proper motion have led him to a most interesting series of papers, some conclusions of which will be re- ferred to in what follows: The third great piece of work to which I have referred is not yet published in extenso, but has been published in part. It exists in maunscript, and the principal conclusions to be immediately derived from it have already been published in a series of interesting papers by Prof. W. W. Campbell, director of the Lick Observatory. Tt is now 16 years since Director Campbell described the Mills spectrograph of the Lick Observatory. This fine instrument, re- modeled in 1902, has been unremittingly used by him until the pres- ent time. A companion Mills spectrograph was installed under Di- rector Campbell’s direction in Chile in the year 1903, and this also has been diligently employed by successive observers sent down from the Lick Observatory. It was Director Campbell’s intention in this long campaign to ob- serve the spectra of all stars brighter than the fifth magnitude, in both the northern and southern hemispheres, in a manner adapted to determine accurately the motion of each of these stars in the line of sight; that is to say, in a direction toward or fromtheearth. This motion is also termed radial velocity. The time of exposure neces- sary for photographing a single spectrum ranges from a few minutes up to several hours, according to the brightness of the star and the quality of the atmospheric conditions. It is necessary in such a campaign as that which the Lick Observatory has been making to ob- serve each of the stars several times in order to confirm the velocity found or to detect the presence of variability of velocity, such as often leads to the most interesting results. The Lick Observatories in California and Chile have observed between 1,000 and 2,000 stars for radial velocity, and these, with a considerable number of others observed by other observatories, made up a list exceeding 1,700 in number, which was discussed by Director Campbell in a series of papers in the year 1911. About one-fourth of the stars observed were found to be spectro- scopic binaries. That is to say, although they appeared to be single points of light to the telescope, yet certain peculiarities in the dis- placements of their spectrum lines from time to time indicated that each of the apparent points of light embraced a system of celestial objects comparable in some respects with the solar system. This similarity, however, does not extend to details, for the objects in- eluded in a spectroscopic binary, or multiple star, are each usually hot enough to give light by itself, and in general are objects of more 188 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. approximately equal size than the sun and the planets. The motions of a considerable number of these spectroscopic binaries have been investigated by mathematicians, and the orbits of the motions have been determined, but there still remains a large number of them for which this information is not yet available. These latter objects were rejected from Prof. Campbell’s general discussion of the stellar motions on account of the indefiniteness which must attend their motions for a time. There are besides a considerable number of stars whose spectra are so vague and difficult to measure that the results from them are uncertain. Accordingly, there remained available for his investigation only about 1,200 objects. The first investigation relates to the motion of the solar system in space. As in a forest walk the trees in front seem to separate as we approach and those behind to come together as we recede, so the stars to the telescopic observer would appear to crowd toward the point of the sky from which we are receding and to separate from that point of the sky toward which we are approaching, if the sun with the planets is in motion in the heavens with respect to the positions of the stars. Such tendencies were noted by Sir William Herschel in 1783, from a consideration of the proper motions of 18 stars, all then available. He found that the solar system was traveling ap- proximately toward the star } Hercules, in right ascension 262°, declination, +26°. The information found by the spectroscope relates to motion at right angles to that which is observed by the telescope, so that while the telescopic observer would find the stars precisely in the solar apex to have no component of motion caused by their relations to the solar system, the spectroscopic observer would find these stars to be approaching the earth with the maximum velocity, while those at the opposite point would be receding from the earth with the same velocity. The telescopic observer, looking at right angles to the line of motion of the solar system, would see the stars at the maxi- mum velocity, whereas the spectroscopic observer, looking in the same direction, would find no radial velocity at all caused by the solar motion. Director Campbell’s general solution for the solar motion derived from all the stars investigated, 1,193 in number, gave the following values: Apex at right ascension, 268°.5, declination +25°.1, and velocity 19.5 kilometers per second. In Prof. Lewis Boss’s discussion of the proper motions of 6,188 stars, he also has derived the position of the apex toward which the solar system is approaching. He finds it in right ascension 270°.52, declination +34°.28, and he finds that for stars situated at 90° from the apex, which of course, will show the greatest apparent velocity of recession from the apex, the mean rate of apparent mo- PROGRESS IN ASTROPHYSICS—ABBOT. 189 tion is 3.85’’ per year. This is called the mean solar parallactic motion for the star group. Now, of course, the parallactic motions of the stars depend upon their distances from the earth, and natur- ally will be less for the fainter stars than for the brighter ones, since the fainter ones are situated at the greatest distances. The mean magnitude of all the stars investigated by Boss was 5.7, but he selects 559 stars having large proper motions whose average magnitude was 5.3 and for which the mean solar parallactic motion was 21.58’. Prof. Boss then goes on to compare the magni- tude and parallaxes of 130 stars ate: parallaxes had been meas- ured, and thereby obtains a formula connecting the parallax and proper motion for stars of the magnitude 5.3. He thus has a meas- ure of the distance of the stars of large proper motion which he is considering, and from this he finds that the velocity of the solar system, in its motion toward the constellation Hercules, is 24.5 kilo- meters (15 miles) per second. Readers will note that this value is derived quite independently from that of Prof. Campbell, and that it is about 25 per cent larger than his. But from the considerations above mentioned (under the caption “ Distances of the stars”) prob- ably a reduction of the estimated distances corresponding to given proper ‘motions will be brought about as more determinations of stellar distances become available. Thus Prof. Boss’s estimate will be brought down toward that of Prof. Campbell. It is found that the fainter stars are on the whole at greater dis- tances from the sun than the brighter ones, so that the star list of Boss relates on the average to a system of stars at a greater distance from the observer than the star list of Campbell. A reason has already been assigned for supposing Boss’s value of the solar motion too high. It may be on the other hand that the sun’s motion is to some extent shared by the stars which are its more immediate neigh- bors, so that its velocity with respect to them is smaller than with respect to the stars which are more remote. Prof. Campbell has adopted in his later discussions the round numbers 270° right ascension and 30° declination for the position of the solar apex, and the velocity of 19.5 kilometers as the rate of its motion toward this apex. With these quantities determined, it is possible to ae from the observed radial velocity of each star a component which depends upon the motion of the sun, and thus to leave to each star its own individual motion with respect to the earth, as the earth would be if fixed in space with reference to the whole system of stars considered. As the sun moves at the rate of 19.5 kilometers per second in a cer- tain direction, so for each of the other stars investigated, there should be a certain velocity and direction of motion. The stars have been classified at the Harvard College Observatory under the direc- 190 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. tion of Prof. E. C. Pickering, with regard to the nature of their spectrum. The principal groups of the Harvard classification are designated by the letters B, A, F, G, K, M. The peculiarities of these types of spectra are indicated in the accompanying plate 3. We see the progressive greater complexity of the spectra from type to type. Campbell points out the very interesting fact that the more complex the star spectrum, the greater the velocity of the star in space, with regard to a point so fixed that the algebraic sum of the velocities of all the stars with respect to it is 0. The same conclusion is derived independently by Boss from a consideration, not of radial motions, but of thwart motions of the stars. The results of Campbell and Boss are compared in the following table. We assume for Boss’s results as for Campbell’s that the velocity of the solar system toward its apex of motion is 19.5 kilometers per second, thus the angular motion observed by the telescope may be converted into its linear equivalent. Unfortunately the grouping of stars by the two ob- servers is different as regards the subclasses of the Harvard classifi- cation. Campbell. Boss. | l Component | Component of peculiar of peculiar Classes. Noe of! velocity | Classes. yee of | “velocity ; (km. per i (km. per second). second). | i Ve B-B5.. 1312 6.2 Oe5-B5. 490 6.4 B8-B9. 90 Geis Teese. Dee ees ee. ee see 172 10.5 B&s-A4. 1,647 9.9 i) ae 180 14.4 A5-FS.. 656 15.8 (CL aie. 118 15.9 Gx egeeee 444 18.1 ee 346 16.8 Bic etree 1,227 14.7 WI eae 71 17.1 ER a 222 16.7 1,289 4, 686 1 For 132 of these stars the radial velocity is estimated. The reader must note that the results, both of Boss and of Camp- bell, relate only to a certain component of the motion of the stars. In the case of Boss it is derived from that component of the proper motion, which is at right angles to the solar pathway; and in that of Campbell it is that component of the radial motion which is in the plane of the star and the solar pathway and is at right angles to the solar motion. If it is assumed that the stars have no preference for motion in one direction rather than another and that they are well distributed over the whole celestial sphere it follows that the values above given from both observers are but half the average velocity of the group of stars, considering their motions in the real directions which they have in space, and not merely the components of motion found by Boss and Campbell. Thus we find for stars of group G, Smithsonian Report, 1913.—Abbot. PLATE 3. e Orionis. @ Carine @ Can. Min. @ Aurigee. & Bootis. & Orionis, TYPICAL STELLAR SPECTRA. From Annals Harvard College Observatory, volume 64, No. 4, plate 1. m3 ‘ “0 Fal = r “ vm _ q =) v1, if 7 | jas eh te Ge A 1 loka er bee - ow ¥ i ; yi o.4; ‘ a - ‘= a » oI a a Ug PROGRESS IN ASTROPHYSICS—ABBOT. 191 to which our sun belongs, an average velocity of 32 or more kilo- meters per second, which is considerably greater than 19.5, which is assigned to our sun. The Milky Way, composed as it is of a vast number of stars, has long been a circle of reference in the heavens for the discussion of the distribution of the stars. Not only are the individual stars crowded more closely in the Milky Way than elsewhere, but the crowding is different with different spectral types. Thus Prof. Pickering pointed out in his discussion of Harvard Revised Photometry that the stars of the early types, type B especially, were to be found prepon- deratingly in the neighborhood of the Milky Way. This tendency of the stars to distribute themselves differently with respect to the Milky Way has been summarized by Prof. Boss in the following tables, in which he gives the numbers of stars of different spectral types to be found in zones at different distances from the center of the Milky Way, and also the numbers of stars of the different types which occur in equal areas in these zones, assuming for the zone +10 to —10° a number of 100. We see that the stars of the so-called “later types” G K M are nearly uniformly distributed over the heavens, but that the stars of the “early types,” especially B, are very unequally distributed, and crowd more and more toward the Milky Way. ENUMERATION OF TYPES IN GALACTIC ZONES. l [TrwG e Zone. Limits. VPM BE AWA BoM. | gh ae M | = | | ° ° | | i Keyan +10 to —10 | 237 422 142 | 103 937 33 | II +10 to +30 105 310 104 63 205 34 Il +30 to +50 4 170 89 66 155 31 | IV +50 to +70 5 100 51 30 102 24 Vv +70 to £90 2 32 13 12 | Son 5 | 1 { RELATIVE AREAL DENSITIES IN PERCENTAGES. Zone. Limits. B A | F | GKM | } ene : 5 ry States. Sto. PF") 100°" A s00" a! 5 * Foor II 410 to £30 47 78 78 87 UI | +30 to +50 7 53 82 R4 | IV +50 to £70 5 47 72 84 | V £70 to £90 5 44 53 76 | In several respects the stars of class B are very remarkable. Dr. Campbell has stated that in a space concentric with the sun, which must contain hundreds of stars of other spectral classes, there would _ probably not be a single one of class B. Thus, B stars are, on the __ whole, excessively remote. In the second place, they seem to be very _ bright stars, for, as Prof. Pickering states, a count of the class B 192 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. stars indicates that of the bright, visible stars one out of four belongs to this class, while of the stars of the sixth magnitude there is only 1 out of 20, and that few, if any, would be found fainter than the seventh or eighth magnitude. It has been strongly intimated by such men as Kapteyn, Campbell, and Boss that the order of spectra B, A, F, G, K, M indicates sub- stantially the order of development of the stars in time, so that the stars of class B may be regarded as the younger stars, and those of classes A, F, G, K, and M, successively, older and older. Prof. Boss goes so far as to say: “ There can scarcely be a doubt that the same stars that are now seen of the spectral type A were in past ages of the spectral type B, and then at a mean velocity of approximately only two-thirds or three-fourths that which they have at present. It seems equally probable that A stars of the present will eventually become stars of the second type in the future, and along with that physical development will acquire an increase of mean velocity about 50 per cent greater than that those stars now have. This fundamental fact of acceleration in the means of the stellar motions must have a vital bearing on questions of stellar development.” It is known that the spectrum of the general surface of the sun, which is like that of stars of class G, goes over into the spectrum of a sun spot, which is like that of stars of class K, by a mere lowering of temperature. It is also known of all bodies with which we are familiar upon the earth, that when, as time passes, they lose energy by radiation they cool. Accordingly it seems probable that stars of class G will at length reach the condition of class K by the mere cooling incidental to the continuation of their radiation to space through long periods of time. The gradual progress in form of spectrum from class B to class M, the gradual progress in velocity of motion from class B to class M, the gradual progress in distribution in space from class B to class M, and other lines of gradual progress which could be named, all seem to show that the arrangement of the stars according to this classification corresponds to the march of a fundamental progress in nature. That this progress is in point of time from stars of simpler spectrum to those of the more complex, and not the opposite, is indicated by the consideration with regard to the sun-spot spectrum which I have just cited. In contemplation of these various facts Prof. Campbell has re- marked as follows: The close relationship of the class B stars to the Milky Way, their low radial and tangential velocities, the apparent absence of class B stars in both near space and distant space, a clustering of many of these stars in apparently related groups—for example, in the Orion region—lead us to believe that the present class B stars assumed stellar form in regions relatively near their 10f Secchi’s classification, in which B to F types are I, G to K are II, and M is III. PROGRESS IN ASTROPHYSICS——ABBOT, 193 present positions. They may have originated from comparatively few great separate collections of matter in or near the plane of the Milky Way. The ? variety of motions which we observe in the stars in one of these apparent groups might, perhaps, have originated from the influence of the passing of } many individual stars through the immense volume of space occupied by the group. The absence of class B stars in our vicinity may indicate primeval vacancy in this region, or the development of the stars in this region to an effective age beyond that corresponding to the class B spectrum. iS Kapteyn has said: } iy at one” that from whatever matter our youngest stars—the helium stars-— may ha.2 deen evolved, that matter must have in all probability still smaller internal motion. Let us eall this matter primordial matter. As the internal velocity of the helium stars is already so very small, we come to the conclu- sion that primordial matter must practically have hardly any other motion than the motion of the cloud to which it belongs. 4 _ As the younger the stars are the smaller are their internal motions, it follows q (i The statements quoted above, and many others which might be quoted from astronomical literature, lead us to the conclusion that their writers assume the following evolution of the universe, begin- ning from the nebula, and proceeding with passing time to the stages of the classes B, A, F, G, K, M in spectra. Originally the matter had very low velocity in space, and as the stars were formed and q grew in age their velocity became greater and greater. Whatever the drift which the original primordial matter may have had, the _ formation of the stars and the gravitation which they mutually exert, together with their increasing velocity in space, tended to alter the motions of the stars from a slow drift in some particular direction to a much more rapid progress of individual stars in every conceivable direction. This motion naturally took the stars of the later types farther and farther from the original seat of the primor- dial matter, so that now, although we find the class B stars still mainly confined to the neighborhood of the Milky Way, yet for other types of stars the dispersion has gone farther and farther. _ For stars similar in constitution to our sun, and naturally of the same order of age as the sun, the circumstances of the wandering have naturally been much the same, so that we find the stars of ap- proximately the spectral class of our sun to be, on the whole, in the less remote parts of space. When, however, we consider the stars _ of most advanced type, of spectral class M, whose wanderings have continued for the most untold ages, we find these stars as a class in the more remote parts of the universe. Although this speculation is supported by a good many facts of observation yet it is only fair to state that there are astronomers q of very high eminence who consider either that the time is not ripe _ for such speculations, or that the evidence may equally well be 1Class B. 44868°-—sm 1913-13 194 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. arranged to suit other conclusions. If we assume the line of specu- lation stated above we must be interested in the following statement of Prof. Kapteyn: There is another problem involved in our observations which might seem to be of no less importance than the one just now considered. How have we to explain the fact that the internal velocity of the stars increases with age? The astronomer who, in the study of the motion of the heavenly bodies, has found hardly a trace of any other force than gravitation, will naturally turn to gravi- tation for such an explanation; and it really seems a necessity that under the influence of their mutual gravitation, bodies which at the outset have little or no relative motion must get such a motion, which, up to a certain limit at least, will increase with time. Thus far there is no great difficulty. But now let us look further back in time, back to the time in which the stars had not yet been formed, in which matter was still in its primordial state. If it be true that mutual attraction of the stars has generated such an enormous amount of inter- nal motion in the time needed by the stars for their evolution from helium to sec- ond or third type stars, how have we to explain the fact that we find that same matter nearly at rest at the first stage of stellar life? That in the prehelium ages gravitation had produced hardly any motion? He who believes in a creation of matter at some finitely remote epoch may find no difficulty in the question, but to him who does not, there is something astonishing to see matter behave as if there were no gravitation. What may be the explanation? Is there really no gravitation in primordial matter, or is there another force exactly counter- balancing its effects? I have no solution to offer. I simply wish to point out that here is a great vroblem, which in my opinion deserves the attention of the physicist no less than that of the astronomer. Cerer ‘Aww onurg *y ‘y Aq uayRy, Mots] a, “JOOY 3JHL NO AYOLVAYSSEO SIH DNIMOHS ‘GYOsSXO LV 3ASNOH S:ASTIVH "| 31v1d syaneg—'¢ 16] ‘Hoday uR}UOsy}IWS THE EARTH’S MAGNETISM. By L. A. BAUER, Director, Department of Terrestrial Magnetism, Carnegie Institution of Washington. [ With 9 plates. | It is indeed a great privilege and pleasure to give a lecture at Ox- ford, where Edmund Halley, whose name the founder has so wisely coupled with this lectureship, labored devotedly in the interest of science; and to be permitted, in some small measure, to pay the debt of terrestrial magnetism, and my own personal debt as well, tc this illustrious investigator. Halley’s varied scientific activity and his wide sympathies were well set forth by the Halley lecturer? of two years ago, who had as his subject an astronomical one, “ The stars in their courses.” Last year’s lecture,? “ Large earthquakes,” by that zealous pioneer, Prof. Milne, again exemplified both the scope of this lectureship and the fact that Halley’s interest and achievements in geophysical science, though not generally so well known as his astronomical discoveries, were no less great. The subject of the lecture to-night, “The earth’s magnetism,” is one in which Halley’s name stands out preeminent among the early students of the science. As it is a large subject and one in which there might be much discursive rambling, we shall do well to limit ourselves somewhat—to choose our starting point and then proceed in certain definite directions. The adopted flag of the Chinese Republic consists of five stripes, partly because, as I am told, in China all good things are five—five seasons, five principal grains, five genii, five relationships that make up life, and five points of the compass, north, south, east, west, and center. lor, to the Chinese, the starting-out point is as important as the point to which, or direction in which, a journey is made. So it also must be with us to-night. +The fourth “ Halley lecture,” delivered in the schools of the University of Oxford on _ May 22, 1913; illustrated by lantern slides. Reprinted, after revision by the author and _ with added illustrations, from Bedrock, vol. 2, No. 3, October, 1913, pp. 273-294. ? Prof. H. H. Turner, D. Se., D.C. L., F.R.S., Savilian professor of astronomy, Univer- sity of Oxford (see Bedrock, vol. 1, No. 1, April, 1912, pp. 88-107). ® Published in Bedrock, vol. 1, No. 2, July, 1912, pp. 137-156. 195 196 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. According to the regulations governing this lecture, it is to be known as the “Halley lecture on astronomy and terrestrial mag- netism.” “Astronomy shall include astrophysics, and terrestrial magnetism shall include the physics of the external and internal parts of the terrestrial globe.” This lecture might, therefore, with propriety cover the whole range of investigation in terrestrial and cosmical magnetism. However, we must limit ourselves to those particular lines of research in our subject in which Halley himself was chiefly interested. It so happens that these are the very lines also in which I have been given the opportunity to continue and expand the work begun by him. After Halley had made two attempts to establish a working theory respecting the distribution of terrestrial magnetism and the cause of its striking change with the lapse of years—the so-called secular variation—he must have reached the conclusion that the elusive problem of the earth’s magnetism would be more profitably advanced by additional facts than by further speculation. That, paraphrasing Seneca, to avoid making a false calculation of matters, it were better to advise with nature rather than with opinion. Ac- cordingly we find him setting out in October, 1698, in command of a sailing ship, the Paramour Pink, and cruising in her under orders from the British Government, back and forth, north and south, in the Atlantic Ocean for two years, observing almost daily, some- times several times in a day, the angle which the compass needle makes with the true north and south line—the angle known to the man of science as the magnetic declination, to the mariner and sur- veyor as the “ variation of the compass.” This is memorable as being the first scientific expedition sent out by any country with the specific object of improving existing knowl- edge regarding certain facts of the earth’s magnetism. Not until somewhat over two centuries later did it occur again, that a sail- ing ship traversed the oceans with the chief purpose of making magnetic observations.’ In July, 1905, there sailed from the port of San Francisco, Cal., a chartered sailing yacht, the Galilee, sent under the auspices of the Carnegie Institution of Washington, on the sole mission to determine the magnetic elements at sea, for the benefit of both the mariner and the man of science, as was also the purpose of Halley’s voyages. Four years later, in 1909, a specially built nonmagnetic vessel, likewise under the auspices of the Carnegie Institution of Washington, left New York for St. Johns, Newfoundland, and thence proceeded to Falmouth, along practically 1 Valuable magnetic data have been secured by various expeditions since Halley’s time, but either the magnetic work was merely incidental or formed part of a general scientific program, or was combined with some geographical object such as Arctic or Antarctic exploration—the memorable Hrebus and Terror expeditions, for example, ee _— See EEE OE EG THE EARTH’S MAGNETISM—BAUER. 197 the same track followed by Halley’s ship. Since then this vessel, the Carnegie, has circumnavigated the globe and has repeatedly intersected the course of the Paramour Pink in the Atlantic Ocean. In view of the historic interest thus attaching to Halley’s magnetic expedition, it will be well worth our while to use this as our starting point or center, the fifth point in the Chinese compass. The instruc- tions given Halley, as far as they pertained to his observational work, were as follows: Whereas his Majesty has been pleased to lend his Pink the Paramour for your proceeding with her on an expedition to improve the knowledge of the Longitude and variations of the Compasse, which shipp is now completely Man’d, Stored, and Victualled, at his Majesty’s charge for the said Expedition ; you are therefore hereby required and directed to proceed with her according to the following instructions :— You are to make the best of your way to the southward of the Equator, and there to observe on the East Coast of South America, and the West Coast of Africa, the variations of the Compasse with all the accuracy you can, as also the true situation both of Longitude and Latitude of the Ports where you arrive. You are likewise to make the like observations at as many of the islands in the seas between the aforesaid Coasts as you can (without too much deviation) bring into your Course; and, if the season of the year permit, you are to stand soe farr into the South till you discover the Coast of the Terra Incognita, sup- posed to lie between Mongolan’s Straits and the Cape cf Good Hope, which Coast you carefully lay down in its true position. In your return home you are to visit the English West India Plantations or as many of them as con- veniently you may, and in them make such observations as may contribute to lay them down truely in their Geographicall Situation. And in all the Course of your voyage you must be carefull to omit no opportunity of noting the varia- tion of the Compasse, of which you are te keep a Register in your Journal. Curiously enough, Halley, though a prominent member of the Royal Society, never contributed a paper to it, nor did he publish anything elsewhere cn these voyages of his, his observations, or resulting conclusions. Not until 1775 were Halley’s journal and observations published, and then by Alexander Dalrymple in his “Collection of Voyages chiefly in the Southern Atlantick Ocean,” from the manuscript in the possession of the Board of Longitude at London. Halley appears to have contented himself with laying down the results of his work on a chart entitled “A new and correct Sea Chart of the Whole World, showing the Variations of the Compass as they are found in the year 1700.” This chart is often briefly re- ferred to under the title “ Tabula Nautica.” The first edition, pub- lished probably in 1701, covered only the ocean—the Atlantic— traversed by Halley himself; for the later edition, as the chart was now to cover the greater part of the globe, he had to collect and utilize observations made by others. No printed reference to the early edition, either by Halley or by anyone else, prior to my dis- 198 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. covery of a copy in the British Museum in 1895 has thus far come to light. Yet this particular chart, termed by me the “Atlantic Chart,” to distinguish it from the later one—the “ World Chart ”— is especially interesting, as it contains the routes followed by the Paramour Pink. Airy, when he reproduced Halley’s “ World Chart ” in the Greenwich observations of 1869, was seemingly not aware of the “Atlantic Chart.”* (See pl. 2.) The only description of Halley’s chart by himself, thus far found, is that either attached to certain editions of the chart or contained on an accompanying leaflet. This, however, is very brief, and was chiefly intended to instruct mariners in the use of the chart. Halley points out that in certain regions where the “ Curves ” run suitably they may be used “to estimate the Longitude at Sea thereby.” To his lines of equal “ magnetic variation” he gave no distinctive name, simply referring to them as the‘ Curve Lines.” Thus he says: “ What is here properly New is the Curve Lines drawn over the several Seas to show the degrees of the Variation of the Magnetical Needle or Sea Compass.” He does, however, use the term “ Line of No Variation.” For some time these lines were referred to by others as the “ Halleyan lines.” Hansteen a century later introduced the term “ isogonic lines,” which is now generally adopted. According to Hellmann, there is reason for believing that some attempts had been made before those of Halley to give on a globe or map a graphical representation of the direction in which a compass needle points. It is conceded, however, that Halley’s was the first successful attempt; his “ variation chart ” was the first magnetic chart based on sufficient observational data to give it immediately both practical and scientific value.? After the publication of his chart—the most important contribu- tion to the observation material of terrestrial magnetism at the time—Halley made no further attempt to establish a theory or to improve on his early magnetic speculations. He appears finally to have adopted the view so clearly formulated by Prof. Turner ?— that the perception of the need for observations, the faith that something will come of them, and the skill and energy to act on that faith—that these quali- ties, all of which are possessed by any observer worthy the name, have at least as much to do with the advance of science as the formulation of a theory, even of a correct theory. 1Those interested in the history of the Halley charts may be referred to the various articles by L. A. Bauer in Nature, May 238, 1895, p. 79, and in Terrestrial Magnetism, January, 1896, and September, 1913; the last-named reference also contains a compilation by J. P. Ault and W. F. Wallis of the magnetic results obtained on Halley’s expedition. 2Mountaine and Dodson, the authors of the second and revised edition (1744) of the Halley Chart, and of the third (1756), published in connection with the latter a small tract, “An account of the Methods used to describe Lines on Dr. Halley’s Chart of the terraqueous Globe, showing the variation of the magnetic needle about the year 1756 in all the known seas, London, 1758, 4°.”” This tract was again published in 1784. 3 Pres. Address, Sec. A, Brit. Assoc. Adv. Sci., 1911. ['ST6T-CO6T ‘WOISuTYSeA JO WOTNINSUT dISoUIVD 9Y} AQ POYST[GBISo SUOT}RIS OTOUSVUL PULT MOYS SIO *O00'TIT JNOGB SBA STET OF GOT IO} SpOSsaA YOM Jo oSvoTrur [eyoT] "SLGL-GOGL ‘SNV3O0O NVIGN] ONV ‘O1SIOVd ‘OILNVILY SHL NI « SIDSNUYVO,, BSHL A@ GNV {8061-GO6L ‘NV30O OlsIOVd SHL NI «33NTVD,, SHL Ad GAMOTIO4 SMOVYL 3HL DNIMOHS dV Ost a. ost ord} Ie ps NE : eal a ae Coaleae ee be ueneg—'¢e 161 ‘Hodey ueluosyyWS Smithsonian Report, 1913.—Bauer. PEATE 5» ‘ Loe sft ga hey ER LI ITER AS wWitaa $i; Th ae a a LT LE jE] pee esa 2 al ay ae wale ee) Pole Austral DUPERREY’S CHART OF THE MAGNETIC MERIDIANS FOR 1836. [If the earth were uniformly magnetized, its magnetic poles would be located diametrically opposite one another. However, because of the complexity of the earth’s magnetic condi- tion, the chord connecting the two poles passes through the earth 750 miles distant from the center. ; THE EARTH’S MAGNETISM—BAUER. 199 We find Halley embracing every occasion— to recommend to all Masters of Ships and all others, Lovers of Natural Truths, that they use their utmost Diligence to make, or procure to be made, Observa- tions of these Variations in all parts of the World, and that they please to com- municate them to the Royal Society in order to leave as compleat a History as may be to those that are hereafter to compare all together and to compleat and perfect this abstruse Theory. Consulting the minutes of the Royal Society, it is found that Halley communicated, from time to time, the results of magnetic observations received from various expeditions, as aiso the values of the magnetic declination observed by himself, at London, viz: 1701, May 7.—Mr. Halley tried the experiment of the Variation of the Needle this day with the two needles he had with him in his late, Voyage; and by the one the Variation was 7° 40’; by the other, 8° 00’ W. 1702, July 8.—Mr. Halley observed the Variation of the Needle, which was found to be 83° Westward, or very near it. 1716, May 24.—Dr. Halley reported that he had drawn a Meridian Line on the stone erected in the Society’s yard before the repository and that the Variation was found at present to be full twelve degrees. These observations of the magnetic declination of 1701, 1702, and 1716 are perhaps printed here for the first time and are not found in any of the compilations of magnetic declinations at London pub- lished thus far. Only Halley’s earlier observations, namely, those of 1672 (2° 30’ W.), 1683 (4° 30’ W.), and of 1692 (6° 00’ W.), hav- ing been given by Halley himself in his printed papers of 1683 and 1692, have become known to compilers. CHANGE OF THE MAGNETIC DECLINATION IN THE ATLANTIC OCHKAN SINCE HALLEY’S CHART. In view of the fact that the two vessels—the Paramour Pink and the Carnegie—both being primarily dependent for their motive power upon the prevailing winds in the Atlantic Ocean, have fol- lowed nearly identical courses, it will be a matter of no little inter- est to compare the values of the magnetic declination given on Hal- ley’s chart for 1700 with those obtained by the Carnegie in her cruises in 1909-10. We find first that over the entire Atlantic, from 50° N. to 40° S., the north end of the compass needle in 1910 was to the west of the compass direction of 1700 by amounts varying with locality. Thus for various important ports the approximate change was as follows: New York, 2°.9 W.; St. Johns, Newfoundland, 14°.6 W.; Falmouth, England, 10°.4 W.; Funchal, Madeira, 15°.6 W.; Bermuda, 10°.5 W.; Porto Rico, 7°.6 W.; Para, Brazil, 14°.6 W.; Rio de Janeiro, 20°.8 W.; Buenos Aires, 13°.0 W.; Cape Town, 16°.2 W. 200 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. If we follow a line passing through the points of maximum change in the Atlantic Ocean, we find for the following points: Values of the magnetic declination in 1700 and 1910. A Secular Latitude. Longitude. Tarstions Carnegie, change lh ath : (1910-1700). 50°.4 N. 30°.4 W. 11°.3 W. 29°.5 W. 18°.2 W. 35°.9 N. 47°.0 W. 4°0 W. 227.1 Wie 18°.1 W. 21°.0 N. 30°.9 W. 0°.6 W. 19°.2 W. 18°.6 W. S°ON. | 35°38 W. 2°.5 E. 16°.5 W. 19°.0 W. 40°.6 S. | 25°.2.W. 10°.7 E. 17°.5 W. 28°.2 W.. We see, accordingly, that the compass direction, in the course of time, suffers large changes; for the region and time interval con- sidered the changes vary from about 3° off New York to 28° in the Atlantic Ocean about midway between Buenos Aires and Cape Town. Even these amounts may not represent the total or maximum change during the period in question. Equally to be noted with these large changes with time is the important fact that the amount of change is as dependent upon locality as is the prevailing compass direction itself, which for over four centuries has been known to be anything but “ true to the pole.” We have thus had impressed upon us this important fact: Two sailing vessels cruising in the Atlantic Ocean from port to port— the one in 1700 and the other in 1910—were forced by the prevailing winds to follow very closely identical courses. If, however, these two vessels had been directed to follow certain definite magnetic courses, and if we may suppose that they had such motive power as to render them independent of the winds, then their respective paths would have diverged considerably. For example, if the Carnegie had set out from St. Johns, Newfoundland, to follow the same magnetic courses as those of the Paramour Pink, stead of coming to anchor in Falmouth Harbor (pl. 3),she would have madea landfall somewhere on the northwest coast of Scotland. In brief, while the sailing directions as governed by the winds over the Atlantic Ocean are the same now as they were during Halley’s time, the magnetic directions or bearings of the compass that a vessel must follow to reach a given port have greatly altered. To quote from the suggestive essay on terrestrial magnetism by John F. W. Herschel : * The configuration of our globe—the distribution of temperature in its in- terior, the tides and currents of the ocean, the general course of winds and the affections of climate—whatever slow changes may be induced in them by those revolutions which geology traces—yet remain for thousands of years appreciably 1Bssays from the Edinburgh and Quarterly Reviews, with addresses and other pieces, by Sir John F. W. Herschel, London, 1857, pp. 69-70. THE EARTH’S MAGNETISM—BAUER. | 201 constant. The monsoon, which favors or opposes the progress of the steamer along the Red Sea, is the same which wafted to and fro the ships of Solomon. Eternal snows occupy the same regions and whiten the same mountains, and springs well forth at the same elevated temperature, from the same sources, now as in the earliest recorded history. But the magnetic state of our globe is one of swift and ceaseless change. A few years suffice to alter materially and the lapse of half a century or a century to obliterate and completely re- model the form and situation of those lines on its surface which geometers have supposed to be drawn in order to give a general and graphical view of the direction and intensity of the magnetic forces at any given spoch. REGARDING LONGITUDE DETERMINATIONS AT SHA. One important result of Halley’s voyage and of the publication of his chart was the awakening of renewed interest in the improve- ment of methods for determining the longitude at sea. Recalling Halley’s instructions, we note that one of the objects of his expedi- tion was “ to improve the knowledge of the Longitude.” When the discovery was made that the magnetic declination varied from place to place, the idea immediately occurred to Columbus, as also to Cabot, that the longitude might be determined at sea by means of this fact. Antonio Pigafetta, who accompanied Magellan on his first voyage around the world in 1522, definitely proposed, in his book on navigation, this method of longitude determination. The line of no magnetic declination, which at that time passed through the Azores, was regarded as the natural meridian from which to count longitude. When later it was found, as was first re- marked by J. de Acosta in his Historia Natural: Sevilla, 1590, that there were four such lines, it was again thought that these quadrantal divisions could be utilized for reckoning longitudes. In 1674 Charles II appointed a commission to examine into the pretensions of a scheme devised by Henry Bond for ascertaining the longitude by the “variation of the compass.” Halley’s chart, however, definitely showed that it would be, in general, futile to attempt to determine the longitude by means of an element so variable and so irregular in its distribution as is the magnetic declination. Nevertheless, the hope that some magnetic phenomenon might yet serve to aid in the solution of this problem did not die immediately. In 1721 we find William Whiston, Newton’s successor at Cam- bridge, installing dip circles on a number of vessels, with instructions to observe diligently the magnetic dip in order to determine whether by means of this element the longitude could be better found at sea than by the magnetic declination; he likewise hoped thus to determine the latitude at sea. It is also interesting here to note that when Dr. Johnson was -at Oxford, he gave in 1756 to the Bodleian Library a thin quarto of 21 pages, entitled “An Account of an Attempt to ascertain the 202 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. Longitude at Sea by an exact Theory of the Variation of the Mag- netical Needle, etc.,” by Zachariah Williams, published at London in 1755; Johnson entered it with his own hand in the library cata- logue. Boswell relates that Johnson himself wrote the English version for Williams, and, in order to make it more extensively known, also had an Italian translation prepared by his friend, Signor Baretti. For fully three centuries the idea that the longitude could be de- termined at sea with the aid of some magnetic element, though proved to be fallacious, served a most useful purpose by furnishing the nec- essary incentive to observe the magnetic elements. This is a striking illustration of the soundness of the position taken by Maxwell when he said: “TI never try to dissuade a man from trying an experiment; if he does not find what he wants, he may find out something else.” It was indeed true of these magnetic longitude seekers that they failed in their purpose, but they contributed data of inestimable value to the advancement of our knowledge of the earth’s magnetism. Before leaving this subject it might be said that Halley himself proposed an astronomical method for solving the longitude problem, and, with Newton, he was responsible for the act of 1714 offering a reward to any person who should devise a satisfactory method for the determination of the longitude at sea. He also improved some of the instruments used in navigation. Another result of Halley’s various voyages deserves mention here, though not immediately concerned with the subject of our lecture, namely, his theory of the cause of the trade winds. On certain editions of his Variation Chart there was given, in addition to the lines of equal magnetic variation, a “ View of the Generall and Coast- ing Trade Winds and Monsoons or Shifting Trade Winds.” COMPLEXITY OF THE EARTH’S MAGNETISM. Reference has already been made to Halley’s attempts, before his magnetic expedition, to establish a theory respecting the phenomena of the compass needle. Thus in 1683 he published in the Philo- sophical Transactions of the Royal Society “A Theory of the Varia- tion of the Magnetical Compass,” and in 1692, in the same Transac- tions, “An Account of the Cause of the Change of the Variation of the Magnetic Needle.” In these papers Halley rejected the hypothesis which had been accepted up to that time, and on the basis of which elaborate tables of the magnetic declination had been constructed by previous investi- gators, namely, that the directions assumed by a compass needle in various parts of the earth could be accounted for by a simple magnet- 1See Miscellanea Curiosa, yol. I, pp. 61-80, and pl. 2, THE EARTH ’S MAGNETISM—BAUER. 208 ization parallel to a diameter so that the magnetic poles would be diametrically opposite to each other. While the conclusion reached by him that “ the whole Globe of the Earth is one great Magnet hav- ing four Magnetical Poles, or Points of Attraction, near each Pole of the Equator Two,” has, in a certain sense, been found to be incorrect nevertheless, this view appears to have been the first definite recog- nition of the heterogeneity or complexity of the earth’s magnetic condition. The increased knowledge gained from magnetic surveys since Halley’s time has taught that the more carefully a country has been explored, i. e., the nearer together the points at which the magnetic elements have been determined, the greater is the number of irregu- larities usually shown by the so-called isomagnetic lines; indeed, re- gions have been found where no system of lines can adequately and correctly represent the prevailing magnetic conditions. We have learned that the regularities in the distribution of the earth’s mag- netism, far from being normal features, as was once thought, are, instead, the abnormal ones, and that the irregularities are the normal and to-be-expected phenomena. The magnetic forces, as measured at any given point on the earth’s surface, appear, according to various analyses, to be the resultant effects of (1) a general or terrestrial magnetic field due to the general magnetic condition of the whole earth; (2) a general terrestrial dis- turbing cause which distorts at the place of observation the general magnetic condition of the earth; (3) a disturbing effect continental in extent; (4) a regional disturbance effect due to low-lying mag- netized substances; and (5) a local disturbance due to the magnetized masses in the immediate vicinity. No formula has as yet been established which will represent the observational facts within the error of observation, in fact not even with sufficient accuracy for the practical purposes of the surveyor and of the mariner. THE BHARTH’S MAGNETIC POLES. We have noticed that Halley, as the result of his study of the observations of the magnetic declination, as far as they had become known up to 1683, reached the conclusion that the earth had “ four Magnetical Poles or Points of Attraction.” Some confusion has arisen as to the precise meaning which Halley attached to his “ poles.” Owing to his alternative term—* Points of Attraction ”—certain eminent writers have sought to identify Halley’s supposed four mag- netic poles with the four foci of maximum total magnetic force, whose existence appeared to be indicated when, near the middle _ of the nineteenth century, it became possible to construct a chart of _ the lines of equal magnetic force. By this incorrect inference these 204 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. authors have unwittingly credited Halley with a discovery which, in the absence at the time of any observation whatsoever respecting the strength of the earth’s magnetic force, he could not possibly have made. The real merit and purport of Halley’s deduction has thereby been obscured. The observation material at Halley’s dis- posal, before he himself enriched the material during his voyages, consisted of some miscellaneous observations of the compass direction and a few values of the magnetic dip. As has been said, there were no observations of the magnetic force, for the art of measuring this element had not yet become known. Scrutinizing carefully his scanty observation material, Halley no- ticed that the direction of the compass needle did not change from place to place in the simple way it would if, for example, the earth had two magnetic poles diametrically opposite each other. In the latter case the needle would set itself tangent to the great circle pass- ing through the magnetic poles and the place of observation. If, then, the compass direction were known at two places sufficiently far apart the points of intersection of the two great circles drawn respectively tangent to these compass directions would be the two diametrically opposite magnetic poles. It is such points of inter- section—“ points of convergence,” as Hansteen later called them— which Halley had in mind as “ Magnetic Poles.” He was the first to perceive clearly the fact—abundantly verified since—that the various points of convergence as found from successive pairs of compass directions, in the manner just described, do not fall together as they should on the basis of a simple or regular magnetization of the earth. However, it appeared to Halley, and the same conclusion was reached over 100 years later by the illustrious Norwegian mag- netician, Hansteen, that the several points of convergence grouped themselves in a general way about two main centers— near each Pole of the Equator Two, and that in those parts of the World which lie near adjacent to any one of those Magnetical Poles the Needle is govern’d thereby, the nearest Pole being always predominant over the more remote. Tt will not be well to lay greater stress upon this deduction nor upon those in his 1692 paper, where he seeks to account for the exist- ence of his four “‘ Magnetic Poles ” and for the secular variation than to say that Halley drew the best possible conclusions the material at his disposal permitted. In fact, his conclusions were not materially improved upon until a century and a half later, when a much more complete knowledge of the distribution of the earth’s magnetism had been gained and when the various mathematical attempts which had been made to compute the magnetic elements on the basis of more or less intricate hypotheses as to the earth’s magnetization, had been found to be inadequate. Some later investigators, indeed, [SI6T-CO6T ‘WOISUTYSBAA JO WOINISUT arSouIND oy Sq PAYST[GBISe SUOT}BIS OTJOUSVUT PUT MOYSS}JOM OOO'TIT JNOGB SBA ETET O} GOGT 1OJ SfossoA GOI Jo osBaTTUr [e190] "SLEL-GOGL ‘SNV30O NVIGN| ONY ‘OlSIOWd ‘OILNVILY SHL NI « 3IDSNUYVO,, . SHL Ad ANY ‘8061-GOG6BL ‘NV30O O1sIOVd SHL NI «3aTIV9,, AHL AP GSMOTIO4 SHOWHL SHL ONIMOHS dV { ! : A . z 206 __.o \oz a | is | ese ee J. .--p----—} —--—} yf pt 8d zt Ost ost Ost oz! | “p ALVId uaneg—'¢e 161 ‘Hodey urjuosyyWS Smithsonian Report, 1913.—Bauer. PLATE 5. DUPERREY’S CHART OF THE MAGNETIC MERIDIANS FOR 1836. [If the earth were uniformly magnetized, its magnetic poles would be located diametrically opposite one another. However, because of the complexity of the earth’s magnetic condi- tion, the chord connecting the two poles passes through the earth 750 miles distant from the center. | THE EARTH ’S MAGNETISM—-BAUER. 205 might have spared themselves considerable pains had they previously familiarized themselves more thoroughly with Halley’s work. When we to-day speak of the earth’s magnetic poles, it is generally recognized that those points on the earth’s surface are meant where the dipping needle stands precisely vertical and where the magnetic dip is accordingly 90°. This definition permits, with the aid of the dipping needle, of a precise determination of the magnetic poles, though, of course, it must not be understood that these poles are mathematical points; the area over which the dip may be found to be 90°, within the instrumental means of determination, may, in fact, be several miles square. A more or less extensive magnetic survey of the region round about would be required to eliminate the possibility of disturbing influences owing to local deposits of iron ore. At these “ Poles,” since the magnetic force exerted by the earth is all up and down, with no side component, a compass needle would have no directive force acting upon it. Some distance before reaching the magnetic pole it would become sluggish, and directly over the pole itself it would be of no more use than a brass needle to indicate any definite direction. (For chart of the magnetic meridian, see pl. 5.) Excluding for the present the purely “ local magnetic poles ” (pl. 8, fig. 2) caused by extraordinary local deposits of attracting masses, all observations to date show that there are but two such points (or areas) where the dipping needle stands vertical, one in the Northern Hemis- phere, located by Capt. James Clark Ross in June, 1831, in latitude 70°.1 north and longitude 96°.8 west (pl. 6, fig. 2),t and the other in the Southern Hemisphere, lying, according to the observations of the recent Antarctic expeditions, about in latitude 72°.7 south and longi- tude 156° east. The magnetic poles, therefore, are, on the average, about 1,200 miles from the geographical poles. Owing to the asym- metrical distribution of the earth’s magnetism, the magnetic poles are not diametrically opposite each other, even if the positions given applied to the same year; in fact, the perpendicular distance from the earth’s center to the chord connecting the magnetic poles is about 750 miles. Let us suppose, now, that one explorer starts out from Oxford, where the compass points at present about 16° west, and follows always the direction shown by the north end of the compass needle, whereas another starts north from Washington, where the compass bears about 5° west, and follows likewise the direction of the compass needle. The paths thus traced out by them are the so-called “ mag- netic meridians,” which, owing to the irregular way in which the earth is magnetized, would not be straight lines or arcs of great 1During Capt. Amundsen’s completion of the Northwest Passage, 1903-1907, he also made observations with a view to locating the north magnetic pole, but the resulting position has not yet been published, 206 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. circles, but more or less devious lines. Could these magnetic merid- ians be followed into the Arctic regions, they would be found to intersect at the north magnetic pole. Owing to the irregular distribution of the earth’s magnetism, the points of greatest intensity of the total magnetic force depart widely in their locations from the magnetic poles. Thus there are in the Northern Hemisphere two distinct maxima of total magnetic force, one in the northeast of Siberia and the other in Canada to the south- west, approximately, of Hudson Bay. A magnetic survey of the latter region is being made this summer by an expedition sent out by the Department of Terrestrial Magnetism. DO THE MAGNETIC POLES MOVE? Possibly the most frequent question asked of those engaged in magnetic work is: “ Do the magnetic poles move with the lapse of years, and if so, why?” Unfortunately, as has already been shown, there are no direct observations as yet on which to base a definite statement. But it would be singular, indeed, if these points remained fixed and were not affected by fluctuations such as are now known from three centuries of observations to exist in every one of the earth’s magnetic phenomena. It is quite possible, in fact, that the magnetic poles pass through certain motions even in the course of a day or suffer displacements during magnetic storms. The diagram (pl. 6, fig. 1) shows the changes in the direction of the compass (magnetic declination), as well as in the direction of the dip needle (magnetic inclination), as far as known, for London, Balti- more, and Boston. Imagine yourself, if you will, standing at the center of a great magnetized needle so suspended as to be free to assume the direction actually taken by the lines of magnetic force at the place of observation, and let us suppose you are looking toward the north-pointing end of the needle. Could you gaze long enough, you would see a curve described in space by the observed end of the needle. This curve would lie on a sphere whose radius is the half- length of the suspended needle and for graphical representation we may take a central projection of it on a plane tangent to the sphere at about the middle point of the curve. The curves here given were constructed by me with the aid of the accumulated observations up to about 1895; the course followed by the needle since 1895 will be dis- cussed later. (PI. 6, fig. 1.) A number of intefesting and instructive facts follow from these curves; time will permit us to give our attention only to the chief ones. It is seen that at London, for example, the compass reached its maximum easterly direction of about 11° in the year 1580, hence during the middle of Queen Elizabeth’s reign; thereafter the easterly te PLATE 6. Smithsonian Report, 1913.—Bauer. By hh L A] if A ) Hie S, 701 | | ra Fil a SS s < 5 ‘s : < a < 7 Fic. 1.—CURVES SHOWING THE SECULAR CHANGE IN THE MAGNETIC DECLINATION AND AND BALTIMORE. BOSTON, ’ IN THE DIP AT LONDON nded magnetic needle of about 50 centimeters, or nearly 20 inches.] sed length of freely suspe [Drawn for suppo STATUTE MILES © 192030 40 50 KILOMETRES 10 20 90 60 Fic. 2.—MAp oF REGION ABOUT THE MAGNETIC NORTH POLE, INDICATING HOW THE COMPASS POINTS IN THE VICINITY. [The earth’s magnetic poles are, on the average, 1,200 miles distant from the geographical poles. ] ‘TIGL OL OOGL ‘NV300 OLLNVILY HLYON SHL JO (NOILYNITO3Q OILSNOVI] ON JO 3NI7) ANI OINODY SHL JO NOILISOg SHL NI SONVHO YvINOIS FuctM 06 wel 2 gis oan yi al of ey) '@IGl PY? OOS] TV 42129 € 2HUONY YMON 24) JO A 2UurT smoby ay yo uoinsod ay) ur vhuoy 7 1wynI22¢ | yond) qvys Te UTLMUTIeP 7 St AR) Yr UO PUD -M St 21217) aya UO epr9 mp wvapur guy Nuoly vif7 jo uwomsod ysoo YM -pormjd 7 mM 842177) SUL TON 02 1c OF 0S 09 06 On BaOT M 0G ‘LZ ALV1d Janeg—'¢ 16] ‘Hodey ueiuosy}iws THE EARTH’S MAGNETISM—BAUER. 207 direction began to diminish until] about 1658, the year of Cromwell’s death, when the needle bore due north and then swung over to the west, continuing to do so until it reached a maximum westerly direc- tion of somewhat over 24° in about 1812. Hence in the interval of about 232 years (1580-1812) the compass direction changed at Lon- don from 11° E. to 24° W., or 35°. At the present time it points about 154° W., or nearly 9° less than in 1812, and a most interesting question doubtless immediately occurs to all of us: Will the freely suspended magnetic needle ever return precisely to a direction taken at some previous time, or is there any definite cycle of changes which will repeat itself from time to time? Here again no wholly definite answer can be given, primarily because of the fact, as will be seen from the diagram, that, if there be such a cycle, it embraces many more years than are covered thus far by the interval of observation. For some European stations, e. g., Paris and Rome, the observation interval is somewhat longer than at London, but still not long enough for definite prediction as to the future course of the magnetic needle. The diagram shows also that in the United States the changes in the compass direction, as far back as they are known, have not been as great as those during the same time at London. Thus, at Baltimore, for example, the compass appears to have reached a maximum westerly amount of about 6.1° near 1670, and a minimum of 2° in 1802, after which, instead of passing through a zero value as at London in 1658, and swinging to the eastward, it turned back and began to increase its westerly direction until at the present time the amount is about 64°. Thus, at this station the compass direction passed from a maximum to a minimum in about 132 years and the total change was but 54°, or only one-sixth to one-seventh of that at London. In brief, the facts revealed by the known compass changes in my country can not be brought in harmony with those witnessed in your country, unless we assume that the length of the cycle of complete change is many times longer than merely twice the period between 2 maximum and a minimum bearing of the compass.. There are evidences futhermore, into which we can not go here, to indicate that the cycle of change at one station is not of the type which would result were we to close the apparently nearly completed curve at London by uniting the two ends in some simple manner. On the contrary, the evidences point to cycles within cycles and to _ the probability that the secular variation curve, instead of being a single closed curve, may consist of smaller loops within a larger one, etc.; it is even questionable whether there ever will be exact closure of the curve. 208 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. There is at present another matter of no little interest with regard to England which should be pointed out here. It will be seen from the London curve that the dip of the needle below the horizon reached its maximum amount of 74.4° in about 1688. At this time the compass changed its direction the maximum amount of 13’ per year. The curve would seem to indicate that the time of a minimum dip is now approaching; this phase has already occurred at Pawlowsk and seems to be now taking place at Potsdam and is traveling west- ward. Whether it will reach London and when can not be answered definitely. However, it is a matter of no little interest, in this connection, to observe that the annual amount of change in the compass direction has in recent years received a remarkable accelera- tion in this part of the earth. Thus, as is shown by the magnetic observatory records, it has almost steadily risen from 4’ per year in 1902 to about 9’ per year in 1912. Whether this portends an early approach of the phase of minimum dip at London is one of the many interesting questions continually arising respecting the perplexing phenomena of the earth’s magnetism. The course of the needle since 1890 has been about as shown by the arrow; thus in 1910 the magnetic declination was approximately 15.9° W. and the dip was 66.9°. One thing more. Note that for each of the three curves as far as drawn, the motion of the freely suspended magnetic needle has been clockwise, i. e., the same as the motion of the hands of a watch. This fact, as shown by the curves in other parts of the world, con- structed with the aid of the available observations, appears to hold generally in both the Northern and Southern Hemispheres, except for certain retrograde motions which thus far have not been of the same extent as the direct one, although, of course, it is not affirmed that they may not become so later. Such retrograde motions are at present being experienced in certain parts of the United States. Thus, for example, the compass pointed in 1910 6.25° W. at Balti- more and 13.35° W. at Boston, and in the same year the magnetic dip was 70.9° at Baltimore and 73.1° at Boston. If we plot these values on the diagram, we shall find that the curves for Boston and Baltimore, instead of progressing in the direction of the arrows, passed through a secondary crest about 1895 and then bent over to the left; how long this will continue can not be foretold. The question as to the cause of the remarkable changes from time to time in the earth’s magnetic condition, as indicated by these curves, has been a fruitful source of speculation since 1634, when Gellibrand definitely proved the fact that the compass direction varies from year to year. Some of the best minds have been engaged with the discovery of the cause, but the riddle is still unsolved. Hence as regards the actual motions of the earth’s magnetic poles and the THE EARTH’S MAGNETISM—BAUER. 209 precise cause or causes, we may still say with Halley that these are “Secrets as yet utterly unknown to Mankind, and are reserv’d for the Industry of future Ages.” A mathematical analysis of the accumulated material shows that, in order to find an adequate explanation of the secular variation of the earth’s magnetism, we must reckon with systems of magnetic or electric forces having their seats both below and above the earth’s crust. There would also appear to be some evidence that in addi- tion to a motion of the magnetic poles or magnetic axes of the earth, we may also have to take into account a possible diminution in the earth’s magnetic moment or intensity of magnetization. THE ORIGIN OF THH EARTH’S MAGNETISM. Before concluding this lecture, we ought, perhaps, in the few min- utes remaining, to say something regarding the status of the ever- recurring question as to the origin of the earth’s magnetism. Assum- ing that the magnetism of our planet is uniformly distributed throughout its mass, it is found that the average intensity of mag- netization is only about one ten-thousandth of very highly magnet- ized hard steel. Prof. Fleming, in his very suggestive popular lecture on the “ Earth, a great magnet,” given at the meeting in 1896 of the British Association for the Advancement of Science, made this statement : Taken as a whole, the earth is a feeble magnet. If our globe were wholly made of steel and magnetized as highly as an ordinary steel-bar magnet, the magnetic forces at its surface would be at least 100 times as great as they are now. That might be an advantage or a very great disadvantage. If, however, we could penetrate the earth’s crust we would find at a distance of only about 12 miles a temperature so great that, according to present laboratory facts, all magnetization would neces- sarily cease. Hence, if the earth’s magnetic field arises from an ac- tual magnetization of the substances composing the earth, these sub- stances must be confined within a comparatively thin shell. But the question immediately arises: Is this argument correct? May it not be that just as the point of liquefaction is raised by increased pressure, so is also the critical temperature of magnetization. It may thus occur that the effect due to increase of pressure with depth of penetration more than balances that due to increased temperature. There are at present no wholly decisive experiments which may be drawn upon to answer this query. The hypothesis that the earth may be an electromagnet also meets with difficulties when we attempt to account for the origin, direction, and maintenance of the required currents. In spite of the accumu- lated facts of over three centuries, we are still unable to say definitely to what the earth’s magnetic field is really due. Perhaps we may 44863°—sm 191314 210 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. not be able to solve the riddle until the physicist answers for us the questions: What is a magnet? What is magnetism in general? In the Devil’s Dictionary by Ambrose Bierce, published in 1911, the following definitions are given: “ Magnet, n.—Something acted upon by magnetism. Magnetism, n—Something acting upon a magnet.” In explanation the author cynically remarks: “The two definitions immediately foregoing are condensed from the works of 1,000 eminent scientists, who have illuminated the subject with a ereat white light, to the inexpressible advancement of human knowledge.” 4 A line of thought first suggested by Schuster and Lord Kelvin, that every large rotating mass, due to an as yet undiscovered cause, may be a magnet, should be considered in conclusion, though we may do so but briefly. If this be true, then magnetism is not confined to our planet alone, but all celestial bodies are surrounded by mag- netic fields. Thus far no laboratory experiment, possibly owing to lack of required sensitiveness in the measuring instruments, has detected any magnetic field arising solely from rotation. Schuster and Swann have recently discussed the character and magnitude of the effects from the possible causes which may operate if the earth’s magnetic field be related in some manner to its rotation. In 1900-1903 Sutherland propounded a theory for the origin of the earth’s magnetism, which, briefly stated, is this: We know that electricity is an essential constituent of matter, and that in every atom, if it be electrically neutral, there are equal amounts of nega- tive and positive electricity. So with the whole earth. Since it is almost electrically neutral, suppose that the total negative charge, while practically equal to the total positive one, occupies a slightly different volume from that of the positive charge, or, in brief, that the volume densities of the two body charges differ slightly, then, because of the rotation of the electric charges with the earth, a mag- netic field arises. I have recently repeated Sutherland’s calcula- tions and, as I had previously found that the earth’s intensity of magnetization increased systematically toward the Equator, I have included a term to represent such a possible effect. The computa- tions show that to satisfy the known phenomena of the earth’s mag- netism, the volume density of the negative charge must be smaller 1 These definitions and accompanying remarks may have had their origin in the follow- ing interesting anecdote told in the American Review of Reviews for August, 1909, of the late Prof. Simon Newcomb, by Mr. A. E. Bostwick, associate editor of the Standard Dic- tionary. Of the definitions in physical science for this dictionary Newcomb had general oversight, and on one occasion he took exception to the definitions framed for the words “magnet”? and ‘‘ magnetism” as based, in the absence of authoritative knowledge of the causes, simply upon the properties manifested by the things. After writing and erasing alternately for an hour or more, he finally confessed, however, with a hearty laugh, that he himself could offer nothing better than the following pair of definitions: “Magnet, a body capaple of exerting magnetic force; and magnetic force, the force exerted by a magnet.” Smithsonian Report, 1913.—Bauer. PLATE 8, Fic. 1.—THE AURORA BOREALIS AS FIRST SUCCESSFULLY PHOTOGRAPHED BY PROF. CARL STOERMER. [Halley was the first to suggest a connection between polar lights and the earth’s magnetism. } Fia. 2.—A LocAL MAGNETIC NORTH POLE AT TREADWELL POINT, NEAR JUNEAU, ALASKA, AS DISCLOSED By L. A. BAUER’S OBSERVATIONS IN 1900 AND 1907. {In the center of the tent the dipping needle stood vertical, with the north end dow ni, and the compass reversed its direction when carried from one side of the tent to the other. Ships’ compasses, a mile away, in Gastineaux Channel, are deflected about 11°. ] ‘O 'd ‘NOLONIHSVAA 4O NOILNLILSN| FISSNYVO ‘WSILANSVI| IVINLSSYYS] JO LNSWLYvd3ag ‘SNIGTING HOYVASSY ill it ill mF nn Wi. i, i. = I Tat 4 ‘ ' IH! 5 *6 ALV1d yaneg—'e16| ‘Hoday ueiuosy}iWis THE EARTH ’S MAGNETISM—BAUER. 211 than that of the positive, or, in other words, the earth’s total negative charge must be distributed through the larger sphere, and, if that be the whole earth itself, then for the chief term involved in the mag- netic potential, the surface of the sphere’ containing the positive charge need be, on the average, only 0.410-° cms., i. e. four-tenths of the radius of an ordinary molecule, below that of the earth’s surface to give a magnetic field of the required strength. Taking the average atomic weight of the earth’s substance in round numbers as 50, the mean volume density of either charge would be about 3.310” electrostatic units. At present there is little hope that a magnetic field, caused just as supposed, can be detected in the laboratory. For a sphere of 15 centi- meters radius, rotating 100 times a second, the magnetic intensity at the poles would be but one hundred-millionth part (10-*) of that of the earth. We thus see that the quantities involved in the solution of one of the great problems confronting the student of the earth’s physics—the origin of the earth’s magnetic field—may be of such a minute order as to be beyond the ken at present of the laboratory experimentalist. Perhaps the effects become appreciable in the case of the earth because of the fortunate fact that it is a body of suffi- cient size and angular velocity. On the other hand, the geophysicist is at a great disadvantage in that he is unable to bring his earth-magnet into the laboratory and to experiment upon it—to reverse the direction of rotation, for example, and see what would happen! Fortunately for him, how- ever, nature comes to his relief somewhat and performs experiments for him on his great magnet on a world-wide scale, by producing in an incredibly short time manifold and at times startling varia- tions and fluctuations in the apparently fixed magnetization of the earth. Thus, on September 25, 1909, there occurred the most re- markable magnetic storm on record, during which, within a few minutes, the earth’s magnetic movement, or intensity of magnetiza- tion, was altered by about one-twentieth to one-thirtieth part. The earth’s magnetic condition was below par for fully three months thereafter. As this severe storm was accompanied by a brilliant dis- play of polar lights, this is the most appropriate place to recall that Halley made the first suggestion of a connection between the aurora borealis and the earth’s magnetism. (PI. 8, fig. 1.) It is firmly believed that a long step forward will have been taken toward the discovery of the origin of the earth’s magnetism when once we have found out what causes it to vary in the surprising manner shown by the secular or long-period changes, by the magnetic storms, and the numerous other fluctuations, such as the diurnal variation, for example. The keynote of modern investigation in 212 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. terrestrial magnetism, as in the biological sciences, must surely be the study of the variations and mutations! Ts it not probable that the very features of the earth’s magnetism regarded at one time as defects—the “constant inconstancies,” as an early writer quaintly put it—will instead become sources of help and inspiration from totally different points of view or in some entirely different line of thought? Who knows of what import the riddles of the earth’s magnetism, characterized by eminent physicists as being, next to gravity, the most puzzling of natural forces, may be, not simply to the magnetician alone, but to all interested in the steady progress of the physical sciences? Thus Schuster suggests that “ atmospheric electricity and terrestrial magnetism, treated too long as isolated phenomena, may give us hints on hitherto unknown properties of matter.” “The field of investigation into which we are introduced,” says Maxwell, “by the study of terrestrial mag- netism, is as profound as it is extensive.” And, says Sabine, one of England’s greatest and most enthusiastic magneticians, “ Viewed in itself and its various relations, the magnetism of the earth can not be counted less than one of the most important branches of the physical history of the planet we inhabit.” MODERN IDEAS ON THE END OF THE WORLD.'! By Gustav JAUMANN, Professor of Physics at the Technical High School at Briinn. We are totally ignorant of the beginning of the world. During the last century the hypothesis of Laplace and Kant that the planets proceeded from the sun and were cast off by the rotation of it enjoyed wide credence. According to this theory our earth was once ina state of glowing liquid. Judging by the increase in temperature in the deep strata, it is covered at the present time by the solidified crust, relatively very thin, on which we live. Such a conception has ren- dered plausible a belief in the deluge and in the idea of a final day of judgment when the world will be devoured by flames. Geology, indeed, records horrible catastrophes: the highest moun- tains were formed by a single short earthquake of tremendous vio- lence, the result of upheavals of granitic magma. By enormous volcanic eruptions erratic blocks were carried thousands of kilometers. In particular the whole of Asia suffered the invasion of the Indian Ocean, which was precipitated on the continent with inconceivable violence, sufficient to carry the rhinoceros and the mammoth, which are considered Indian animals, as far as the frozen fields of Siberia. Cuvier affirmed not only that the world would be destroyed some thousands of years hence, but that it has already many times under- gone like cataclysms, each geologic formation constituting the burial place of a creation entirely separate in origin. According to this hypothesis, the termination of each geologic period has been marked by a complete ending of the world, and the opening of each succeed- ing period by a special creative act giving birth to a new fauna more perfect but equally incapable of evolution. By the side of the brilliant Cuvier lived, obscure and unknown, the much greater Lamarck. It is he who recognized the continuous evolution of the _ faunas in accordance with an immanent law, or at least in conse- | quence of the capacity which organisms possess of perfecting them- 1 Inaugural address of the rector of the Imperial German Franz-Joseph Technical High School at Briinn, delivered on October 26, 1912. Translated from the German, pub- lished by the technical high school, by permission of Prof. Jaumann., 213 914 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. selves by assiduous exercise and by communicating in part to their descendants the improvements thus acquired. It is this way of thinking which, after a turn toward Darwinism,' has finally estab- lished itself. Now, to permit such an evolution of the organic world, from the beginnings to its actual perfection, requires a consid- erable duration of cosmic quiet. Geologic investigations since Lyell have indeed demonstrated that the passage from each geologic forma- tion to that succeeding it is made gradually and without interruption. The inundations and volcanic catastrophes which are produced at all times, far from destroying worlds, have never been more than purely local. Volcanic eruptions are not the index of a fluid and incan- descent nucleus, for the accumulations of liquid lava have little extension, so that even neighboring volcanoes, such as Vuleano and Stromboli, have no relation to each other. One can even affirm that the fiuid incandescent nucleus of the earth does not exist. Recent physical observations, especially those relative to the transmission of the transverse seismical waves through the interior of the earth and to the period of migration of the terrestrial axis, admit of the conclusion that the earth in its entire mass is as elastic as a steel of good quality. But now we must observe the very disquieting previsions of the exact sciences. These we must notice particularly, for physics and astronomy have exact natural laws, and in this way may be predicted in all probability the most distant consequences, for the laws which are concerned here, that of gravitation and that of the conservation of energy, are among the ones most firmly established. The real achievement of Newton was to show that the law of gravitation had a more exact application than the laws of Kepler according to which the planets move along their elliptical orbits.?, In reality the planets do not describe strictly elliptical trajectories. The form and the position of these trajectories change constantly, although with extreme slowness. The law of Newton affords an explanation of the greater part of these divergences, if the reciprocal 1In this connection we designate as Darwinism only that part of Darwin’s teachings which originated with himself; not the evolution theory, which is due for the most part to Lamarck, but rather the theory of selection, according to which there could not be any evolution of the organic world without the influence of selection in connection with the struggle for existence. 2The law of gravitation itself was not originated by Newton, but by Kepler, whose ideas exerted a powerful influence on Hooke, Halley, and Fermat. It was first formu- lated mathematically by Wren, whose physical work was otherwise unimportant. Newton only contributed proof of its correctness. Kepler originated the fundamental and extraordinary new conception “ Virtutem, quae planetas movet, residere in corpore Solis’’ (‘‘'The power which moves the planets resides in the mass of the sun’’—heading of ch. 33 in Kepler’s “Astronomia Nova.’’ See “ Jo. Kepleri Opera Omnia,” Frisch’s edition, vol. 8, p. 300). He also originated the idea of the field of gravitation, in which the force diminishes with the distance from the sun, and the idea of universal gravitation. Had Galileo’s dynamics controlled Kepler as it did Huyghens, he would not have needed half his genius to have anticipated Newton’s con- tributions to the subject. MODERN IDEAS ON THE END OF THE WORLD—-JAUMANN. 215 attractions of the planets are taken into consideration. Taking these deviations into consideration, it is possible at present to calcu- late to within a few seconds the positions of the sun, the moon, and the planets a hundred years in advance. But to determine at a dis- tance of millions of years the end of the Newtonian world enormous mathematical difficulties must be overcome; indeed, it is a matter concerning the problem of the stability of the planetary system and of calculating whether the disturbing influences, weak but incessant, which the planets exercise upon each other will nearly counteract each other in time or will end by entailing the destruction of the planetary system. Eminent scholars have always taxed themselves with resolving this fundamental problem relative to the stability of the world. Laplace and Lagrange showed, by means of an approximate calculation, that the planetary system of Newton appeared to be stable. Poisson demonstrated that by further refining the calculation later epochs could be surveyed, in which greater and greater fiuctuations in the form of the planetary orbits were present. Finally Poincaré proved that by carrying the calculation to its limit, a future time was dis- closed in which the planets would experience unlimited, progressive, so-called secular disturbances and, finally, some of them would fall into the sun, and others lose themselves in the cold of cosmic space. Thus, the planetary system of Newton has no stability, no internal constancy. But the foregoing calculations were made on much too favorable a basis. Cosmic space can not be empty, as Newton held. Since it can transmit light, it must be filled with a medium, ex- tremely tenuous and cold, called cosmic ether. The extreme vacuum obtained in the laboratory, cooled to —170° C., presents a con- siderable viscosity, which is only ten times inferior to that of the normal air.t_ Consequently, the cosmic ether must oppose to the movement of the planets a very appreciable frictional resistance. They must continually lose energy of motion; in addition to which, the attractive action of the sun becoming more and more considerable, the planets should describe orbits more and more narrow and should end, in some millions of years, by precipitating themselves into it. Thus, again, we have the “igneous” death of the earth. But that end would be preceded by the destruction of the terrestrial organisms, all being menaced by death from the cold, which would set in much earlier. 1This extreme vacuum at —170° C. has the modulus of viscosity 2X10°% c.g. s. To overcome the resistance that the ether offers to our earth would require more than 150,000,000 horsepower. Meteorites must glow in the ether if their diameter be less than 50 cm. As a matter of fact, a glowing meteorite has been observed at a height of some 780 kilometers (above Sinope on Sept. 5, 1868, reported by G. von Niessl in Verhandl. d. naturforsch. Vereines in Britinn, vol. 17, p. 316, 1879), and even in the spectrum of the comets when approaching perihelium (when their velocity is greatest) clear indications of the glowing of solid bodies have been observed. 216 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. The energy thrown out with the sunlight is several billion times greater than the total interchange of energy which takes place on the earth. The sun gives off continually enormous quantities of it, and its supply, of whatever unknown kind it may be, must finally be exhausted. It would cool down more and more, and our civilization, after terrible struggles, would meet with disaster more and more amidst the ever-present ice. Thus the two fundamental physical laws lead, it is seen, to essen- tially gloomy consequences, but, with all the respect that is due to their sublime results and to their precision, it is only right to ask whether they are really established with such ideal exactness as to enable one to draw conclusions applicable to epochs immensely re- mote, and to comprehend the very plan of creation. Before accept- ing these consequences, it will be well to submit these inexorable laws to a much more searching scrutiny. That the law of gravitation will not support an examination carried to extreme limits, nearly all as- tronomers agree in admitting. The most striking deviation from this law is offered us by the moon, which undergoes an inexplicable ac- celeration, not less than 6 seconds per century. An analogous anom- aly, more marked and still more complicated, has also been recog- nized in the motion of Encke’s comet. The orbit of Mercury pre- sents an inexplicable perihelic rotation, attaining 40 seconds per century, and its eccentricity is not augmented with the rapidity which the law of gravitation demands. The orbit of Mars is subject to anomalies of the same nature, while the inclination of the orbit of Venus increases too rapidly by 10 seconds every century. Terrestrial gravity presents, even from the point of view of direction, a diurnal and annual oscillation of a fraction of a second, which is not to be explained alone by the attraction of the moon or of the sun.2_ It is true that these are relatively small and isolated deviations, and that in general the law of gravitation suffices for the calculation of the mo- tions of the stars with a sufficient approximation, always assuming that the cosmic ether is absolutely devoid of friction. This latter, however, is far from being accepted by physicists. When one con- siders that the periodic comets, even the smallest ones, apparently undergo no frictional resistance, that they are capable of penetrating the solar corona at a speed of 5,500 kilometers per second, without undergoing appreciable loss, one is obliged to admit that the law of gravitation is not sufficient, but that forces unknown, though hinted at by Kepler, act upon the stars in motion, and tend to offset the ef- fects due to friction of the cosmic ether. It is a fact that no trace, however slight, of a beginning of the falling of the planets toward the sun, as the law of Newton predicts, has yet been shown. The same 1G. H. Darwin, Tides, 1898, p. 125; O. Hecker, Publications of the Royal Prussian Geodetic Institute, No. 32, 1907. Se a ee ee MODERN IDEAS ON THE END OF THE WORLD—JAUMANN. 217 may be said of the cooling of the sun, which should follow in ac- cordance with the law of energy. It was supposed for a long time to be self-evident that the climate of the earth had grown constantly cooler, but this idea has been entirely abandoned. Fluctuations less than 10 degrees centigrade on both sides of the mean temperature have often occurred, several times in Europe, thus placing these regions now under tropical conditions, and now under the conditions of the Arctic Zone. But from this point of view the most remote ages of the geologic history of the earth differ not at all from the present epoch. Glacidl formations, extensive but not thick, have been found in early Cambrian strata.1 | At that time the tempera- ture was not higher but lower than in our epoch, and more than a hundred million years have passed since then. One can with difficulty admit of the existence in the sun of a supply of energy able to endure without appreciable decrease, for so long a time, the enormous expenditure due to radiation. The sta- bility of the planetary system and the inexhaustible luminous power of the sun are, furthermore, to a certain extent verified by direct geologic observation. How is it that the law of gravitation and the principle of the conservation of energy fail so entirely in their prophecy concerning the end of the world? What is the hidden defect of these laws which, as the foundations of physics, have given such magnificent results within narrower limits, and how can they be given an en- tirely correct form ? Regarding these really fundamental questions of theoretical physics, I feel myself called upon to speak, in so far as they fall within the field of my own studies. I should point out, however, that questions are concerned which are far from being decided, and that I can treat here only their “ phenomenalistic” aspect. The Newtonian hypothesis of the attraction of a star on a remote body, directly and instantly, without the physical intervention of an in- termediary medium, was an abstraction nearly accurate, though at bottom little true to nature. Laplace himself admitted the progres- sive transmission of gravitation.?, He supposed that this effect was propagated, though at great speed, through the cosmic ether. The magnetic forces between two magnets were likewise supposed at first to act immediately at a distance. Faraday recognized eventually that the air or similar medium contained between the two magnets (the magnetic field), far from being indifferent, was in a state of tension, and that the magnetic effects of one magnet on another were propagated from point to point, from one particle to the particle immediately adjoining it. It is thus that the elementary action 1Compare, for example, Walther, History of the Earth, 1908, p. 199. 2 Laplace Mécanique céleste, vol. 4, p. 317. 218 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. is always produced in ultimate particles situated in the magnetic field, and its law is a differential law expressing the relation of cause and effect between the existing conditions and their causative predecessors in each ultimate particle of the space. It is from the interaction between all the ultimate particles of the magnetic field in the so-called integral that the effects at a distance result. Maxwell established the laws of effect from point to point of electromagnetism (or differential laws of the electromagnetic field), which with an admirable simplicity not only explained the electromagnetic phe- nomena formerly known (which the laws of effect at a distance were equally capable of doing), but did much more; they predicted, in- deed, the propagation of electric vibrations through space in the form of electromagnetic rays. The luminous rays appeared thus as electromagnatic rays. Hertz obtained, with purely electromagnetic resources, electromagnetic rays of great wave length, and Marconi has utilized these same rays in wireless telegraphy. Thus it is that one of the greatest and most. difficult advances in the theory, the transition from laws of effect at a distance to theories of effect from point to point, led immediately to a great technical advance. At that time (more than 20 years ago), many physicists, Hertz and Mach in particular, recognized that the real object of the theory was to explain physical phenomena by differential laws, a task which seemed to pass much beyond the attainable, but it has been in large part satisfactorily performed,* since at present the law of gravitation itself can be expressed in the form of a law of effect from point to point.2 The end sought in this connection consists in dethroning the old corpuscular and mechanical theories still so full of vigor. The list of facts brought forth by the two contending parties increases in length from year to year and the struggle between phenomenalistic investigation and mechanical investigation is waged on a field of great extent, embracing almost the entire domain of the exact sciences. The combat centers around the question of the nature of light and of the cathode rays. The new theory of gravitation is only a partial victory 1G. Jaumann, A complete system of physical and chemical differential laws, Sitz- ungsber. K. Akad. Wiss. Wien, Math.-Naturwiss. Kl., vol. 120, pt. 2a, 1911, pp. 385-530. 2G. Jaumann, The theory of gravitation, Sitzungsber. K. Akad, Wiss. Wien, Math.- Naturwiss. KI., vol. 121, pt. 2a, 1912, pp. 95-182. The majority of physicists still subscribe to the emission theory of cathode rays (the corpuscular or emissional theory) and there is a tendency, under the leadership of Hinstein and Planck, toward giving up finally the essential features of the classical theory and going back to a sort of emission theory of light. Regarding the undulation theory of cathode rays and the phenomalistic undulation theory of light in dispersion media, see G. Jaumann, The electromagnetic theory (Sitz- ungsber. K. Akad. Wiss. Wien, Math.-Naturwiss. K1., vol. 117, pt. 2a, 1908, pp. 379-543), which paper was rejected by the editors of the Annalen der Physik in 1908 and in 1911 was honored by a prize by the Imperial Academy of Sciences in Vienna. See also BE. Lohr, The boundary conditions in G. Jaumann’s electromagnetic theory (Sitzungsber. K. Akad. Wiss. Wien, Math.-Naturwiss. Kl., vol. 120, pt. 2a, 1911, pp. 1503-1567, and vol. 121, 1912, pp. 683-678. SSS > MODERN IDEAS ON THE END OF THE WORLD—JAUMANN. 219 on the extreme wing, but by virtue of it we now have exact notions regarding the manner of propagation of gravitation through the cos- mic ether. The anomalies of the field of gravitation compensate each other in cosmic space, according to a law analogous to that which rules the irregularities of the distribution of temperature in a good con- ductor of heat. It is only for stars in a state of repose that the New- tonian law of effects at a distance follows exactly from the differentia] law of gravitation. Now, the motions of the planets produce disturbances, a kind of damming up, so to speak, of the field of gravitation in front of the moving stars, giving birth to new forces of gravitation added to the Newtonian forces. Although very small, it can be determined with precision that the most important among them has the same direction as that of the motion of the planet to which it is a stimulus. It in- creases with the speed of the planet and varies in inverse ratio to the distance separating it from the sun. These new forces of gravitation introduce into the planetary movements disturbances which can be calculated without difficulty, and even cause the deviations from the Newtonian law which we have mentioned above. By them are ex- plained the anomalous perihelic rotations, accelerations, oscillations of the vertical, ete.—that is, all the phenomena of gravitation, without any being left over, which the Newtonian law of effects at a distance was incapable of doing. These new forces of gravitation moreover give to the planetary system a physical stability of unlimited dura- tion. They keep the planetary orbits in their present form, not only in spite of the very considerable resistance due to friction of the cosmic ether, but.also in spite of enormous accidental disturbances. ‘If a disturbance of this nature (which might be due, for example, to the passage in the neighborhood of the solar system of a fixed star imbued with a very rapid motion of its own) should be produced, and modify entirely the form of the planetary orbits, the new forces of gravitation would introduce into the elements of the orbits such vari-. ations that these planetary orbits would gradually return exactly to their existing stable form. Far from becoming dangerous, the fric- tional resistance of the cosmic ether, on the contrary, helps essentially to make the planetary orbits stable. The greater this resistance the more considerable become the new forces of gravitation and the more obstinate the planetary orbits in conserving, in spite of all the disturb- ances, their stable form. Thus there can no longer be any question of the planets dropping into the sun. Far from being unstable, far from tending toward a destruction more or less remote, the planetary sys- tem is, then, established for a duration which, estimated according to the ideas of time that we are able to conceive, may be considered as eternal. 220 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. The absolute validity of the principle of the conservation of energy is incontestable, but its new differential form+ leads in entirely new directions. The cause of the indefinite constancy of the temperature of the sun rises from the inevitable reaction of the differential law of gravitation on the law of the propagation or radiation of energy and in particular the differential law of the conduction of heat, established by Fourier. The forms of the two differential laws must be placed in opposition to each other in order, when taken together, to correspond to the principle of energy. The very considerable role which the mass of bodies plays as the cause of the concentration of the forces of gravitation demands a corre- sponding influence of the mass of bodies on the concentration of energy. To the radiation of energy called the flow of heat there corresponds a new flow of energy in the direction of gravitation. Thus the law of the conduction of heat established by Fourier is strictly applicable only to media of extremely slight density. In dense substances there must be a hitherto unrecognized concentration of energy, and this is not an hypothesis, but simply the balance of the system of laws of effects from point to point. All dense bodies should in consequence produce heat incessantly and spontaneously. All bodies are so many radiators functioning without loss, although in very different and to us generally imperceptible degrees. Far from being in contradiction to the principle of energy, this fact springs exactly from its expression in the form of the law of effect from point to point. The salts of radium, indeed, produce a similar effect of spontaneous radiation, but this is of such an exceptional intensity that it has amazed the physicists. Upon its discovery doubts were conceived of the validity of the principle of energy, but it is only the integral form of the principle which gives place to these doubts, while the differential form, or the law of effect from point to point, is thus all the more firmly established. The increase of temperature in the deep strata of the earth is explained by this effect of spontaneous radiation without the intervention of the hypothesis of deposits of radium. Moreover, there is produced toward the sun an enormous concentration of the new radiation of energy arising from the field of gravitation, which compensates for the loss of energy which the sun undergoes and assures the permanent constancy of its mean temperature. Consequently the sun yields no energy at all to the wide circle of cosmic space; that which it radiates into cosmic space is recovered in the form of this flow of energy from the field of gravitation. The senseless waste of the sun’s energy, of which the theory of effects at a distance seems to 1G, Jaumann, Sitzungsber. K. Akad. Wiss., Wien. Math.-Naturwiss. Kl., vol. 117, pt. 2a, p. 388 et seq.; vol. 120, p. 398 and p. 505; vol. 121, p. 169. Pe ee MODERN IDEAS ON THE END OF THE WORLD—JAUMANN. 221 prove the existence, is shown by the theory of effect from point to point to have no place in nature. A cooling off of the sun will not bring the development of our civilization to a stop, after which, through the deterioration of the climate, it will disappear and the last men will live like Eskimos on the entirely glaciated earth. The radiation from the sun being stable, the intellectual and physical evolution of humanity will be able for an immeasurable time to mount to heights surpassing, perhaps, anything the imagination is capable of conceiving. Thus, as a result of the development of the differential theories, a new and unsought contribution to cosmology of high and moral value has been obtained. 4 b | P h RECENT DEVELOPMENTS IN ELECTROMAGNETISM.* By EvuGENE BLocH, Professor at the Lycée Saint Louis. The domain of electromagnetism is to-day so broad and so com- plex that in a few pages we can not hope to show all its frontiers. For the present, therefore, we will limit ourselves to reviewing cer- tain problems which particularly attract our attention, either by the number or the importance of the investigations which they have produced. We will start with the theoretical developments and end with the results gained in the laboratory.’ I. THE DYNAMICS OF THE ELECTRON AND ELECTROMAGNETIC MASS. The electromagnetic theory of matter and the ether in the per- fected form due to H. A. Lorentz is really a theory of electrons. Matter in all its forms is by it considered as made up of complex groups of which an essential element is the negative electron either free or bound to an atom. This element is defined by its charge ¢ (4.5X10- electrostatic units) and its mass, which is invariably at small velocities (e/m=1.76 10" electromagnetic units). This result was the logical consequence of a long and brilliant series of discov- eries which marked the end of the last and the beginning of the present century (cathode rays, X rays, gaseous ions, Zeeman effect, radioactivity, etc.). A fundamental problem of this theory is evidently the study of the motion of an isolated electron and the electromagnetic perturba- tions which accompany it. This problem gains in interest as experi- mental demonstration becomes possible. Cathode rays from all sources (rays from Crookes’s tubes, from the photoelectric effect, the 8 rays from radium) are, indeed, fluxes of electrons projected at great velocities from matter. Let us, therefore, review first the important results of the theory which was developed by Heaviside 4 Translated by permission from Revue générale des Sciences pures et appliquées, Paris, 24th year, No. 8, Apr. 30, 1913. 2Tt will be out of the question, for instance. in this review to consider the recent researches on the larger ions, X-rays, radioactivity, vacuum tubes, and the phenomena connected with them (positive rays, etc.), or atmospheric electricity. 223 224 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, and Searle and later and fundamentally by J. J. Thomson (1881), a theory which has passed through many successive developments. (1) An electron moving with a uniform velocity, or at least a velocity only slowly variable (quasi-stationary), carries invariably tied to it an electromagnetic field the form of which can be com- pletely deduced from the Maxwell-Lorentz equations. This moving field has been called the “ velocity wave.” ; (2) If the electron suffers an acceleration, a wave is immediately propagated from it having all the characteristics of a luminous wave (transverse vibrations, rectangular electric and magnetic fields). This disturbance has been called an “acceleration wave.” At great distances from the electron the latter wave alone exists because its amplitude varies inversely as the distance from the electron and not as the inverse square as does that of the othér wave. This shows us the probable origin of luminous radiations and the root of the expla- nation of the Zeeman effect. Here also we find the explanation of X-rays which are electromagnetic pulses? due to the abrupt stoppage of cathode corpuscles at the anticathode and the resulting negative acceleration. (3) In order to give an electron a quasi-stationary movement there must be communicated to it energy which is stored up in its field as electric and magnetic energy. The necessary calculations for this field are relatively simple where the ratio (@) of the veloc- ity (v) of the particle to the velocity of light, V) is small. They become more complicated where @ approaches unity and were first made completely by Max Abraham ® in 1903 upon the hypothesis of a rigid, spherical electron carrying a charge uniformly distributed throughout its volume. Then the magnetic energy of the field can 2 always be expressed in the form of kinetic energy, > It is quite natural to speak of the coefficient m as the electromagnetic mass of the electron. This mass may be superposed upon the ordi- nary mass, at least it does not wholly take its place. This leads to an electromagnetic interpretation of mechanics. In this new me- chanics, the mass m does not maintain a constant value m, except at very small velocities. For a velocity comparable with that of light (8 near 1) the mass becomes a function of $ and increases indefinitely as @ approaches unity. Further it is necessary to dis- tinguish between a longitudinal and a transverse mass according 1See the references cited further on. 2We have not sufficient space to describe the curious theory of Bragg according to which the X-rays and the 7 rays of radium are uncharged particles of matter. More- over this theory appears to be contradicted by the recent beautiful experiments of Lane and his pupils upon the diffraction of X-rays by crystals. (Bragg, Phil. Mag., Oct., 1907; Chem. News, vol. 97, p. 162, 1908; Radium, p. 213, 1908. See also articles by Brunet in this Revue for Feb. 15, 1913.) 3 See Ions, electrons and corpuscles, vol. 1. DEVELOPMENTS IN ELECTROMAGNETISM—BLOCH. yey to the orientation of the accelleration with regard to the velocity. The transverse mass, detectable only in the experiments with the deviations of the cathode rays, is given according to Max Abraham by the relation m_ 3 1+? a 1+8 m, 46°\ 28 pal This formula seemed completely verified by the observations of Kaufmann! (1900 and 1903). He measured the variation of the ratio e/m with the velocity for the @ rays from radium, utilizing the electric and magnetic deviations of the electrons having veloci- ties reaching ninety-five one-hundredths of the velocity of light. Since then other formule have been proposed in the place of this. Langevin and Bucherer,’? basing their formula upon the ee of a deformable electron of constant volume, obtained Bee Further, as a consequence of the development of the theory of rela- tivity (see Sec. II of this article), H. A. Lorentz, postulating an electron of constant equatorial diameter, deduced a third formula: These new formule also appear to fit the experiments of Kaufmann. It became necessary, therefore, to make new experiments more pre- cise than those of Kaufmann in order to choose between the various formule. Several attempts to do this have been made. Bucherer® placed a grain of radium fluoride at the center of a condenser formed of two flat disks 8 cm. in diameter and séparated by 0.25 mm. This condenser was inclosed in an air-tight cylindrical box, the walls of which carried a photographic film. This was all placed in a uniform magnetic field parallel to the plates and a very perfect vacuum produced. When the condenser is charged, the @ rays trace upon the film a line the analysis of which permits the ealculation of the variation of e/m with the velocity. In this case the formula of Lorentz is found to fit best, confirming nicely the principle of relativity. 1 See Ions, electrons and corpuscles, vol. 1. * Langevin, Revue générale des Sciences, p. 267, 1905. ? Bucherer, Physik. Zeitschrift, vol, 9, p. 755, 1908; Annalen der Physik, vol. 28, p. 513, 1909. 44863°—sm 1913——15 226 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. These conclusions have been clenched by yet later experiments. Hupka! used the electrons from the photo-electric effect, produced in a very perfect vacuum and accelerated by intense electric fields reaching a strength of 90,000 volts. The knowledge of the velocity v and the ratio e/m was deduced from the magnetic deviation, rendered evident by a fluorescent screen, and the magnitude of the accelerating potential. The maximum velocities obtained were of the order of v/2. The formula of Lorentz fits these observations also better than that of Abraham. However, these experiments are less convincing than the preceding ones, as Heil noted,’ since the highest potentials must be known with a precision greater than 1 per cent, an accuracy difficult to obtain. C. E. Guye and Ratnovsky,® desirous of escaping this difficulty, used ordinary cathode rays, produced in a good vacuum, and deviated at the same time both electrically and magnetically so as to get rid of the necessity of measuring the potential used. These results also confirm Lorentz’s formula at the expense of Abraham’s. We are led by all these results to look upon an electron as deform- able only in the direction of its motion, conformable with the prin- ciple of relativity; in this respect they undergo the contraction of Lorentz (see further on). Do all difficulties now disappear? With- out considering the objections of a more general nature which are to-day urged against the principle of relatively (see Sec. Il), we must say,no. As H. Poincaré‘ has observed, we can not comprehend why an electron does not disintegrate spentaneously under the in- fluence of the electric and magnetic forces due to its charge unless there comes into play, in order to maintain equilibrium, other forces from without analogous to pressure. We are led thus to introduce something further than pure electromagnetism as a basis of our new mechanics. We are just as far as ever from comprehending the primordial forces underlying matter. II. THE PRINCIPLE OF RELATIVITY. Lorentz has shown that the electromagnetic theory furnishes an explanation of the negative results of the experiments which were expected to demonstrate, either by electrical or optical means, the movement of translation of the earth relative to the supposed sta- tionary ether. These experiments could detect only the effects of the first order with reference to 8 (quotient of the velocity of trans- lation of the earth, v, relative to the velocity of light, V), while 1 Hupka, Verh. der Deutsch. Phys. Gesellsch., vol. 11, p. 249, 1909; Annalen der Physik, 1910. 2 Heil, Annalen der Physik, vol. 31, p. 519, 1910. 3 Guye and Ratnovsky, Comptes Rendus, CL, p. 326, 1910. 4H. Poincaré, Rendiconti del Circolo Math, di Palermo, vol. 21, p. 129, 1906. DEVELOPMENTS IN ELECTROMAGNETISM——BLOCH. 92% theory shows that the effects should be of the order of @? or smaller. This theory then received a rude shock from the celebrated experi- ment of Michelson (1881) relative to the interference of two rays propagated at right angles to each other and which should show the terms of the second order of 8. The negative result was irrec- oncilable with the theory, the effect observed being less than one one-hundredth of that calculated... We must therefore modify the theory. The modification necessary was announced almost at the same time by Lorentz and by Fitzgerald. It consisted in supposing that a moving solid body suffers a contraction in the direction of its motion equal to 07/2. This is the celebrated hypothesis known as the “ con- traction of Lorentz.” It seems very strange at first sight and insti- gated the experiments by Lord Rayleigh,’ and by Brace,’ who tried to find evidence of this contraction in the double refraction which it should produce. Their results were negative. In order to explain these consequences and place the theory in a more satisfactory form, Lorentz was led to a hypothesis which contained the germ of the theory of relativity.*| He showed that the electromagnetic equations for bodies in motion could be put in the same form as for bodies at rest by means of what is called the “transformation of Lorentz.” This permits the expression of the coordinates x, y, 2, and the time ¢ for a system i motion as a function of the coordinates %, %, Zo, and ¢, for the system at rest, thus establishing a correspondence between the electric and magnetic fields of the two systems. This group of transformations contains, as a particular case, the hypothesis of con- traction, which is found to be of the magnitude (1-@?)4, in agree- ment almost to terms of the fourth order with the magnitude origi- nally admitted. It further explains the negative results of Michel- son, Rayleigh, and Brace. Through it we understand the negative results of Trouton and Noble in their electrostatic experiment which was expected to indicate the terms in @?.° The experiments explained by the transformation of Lorentz go only to the terms in $?. We do not know any at present which go further, but it is natural to suppose that even taking into account terms of higher orders, we will never be able to get evidence of the motion of translation of the earth with reference to the ether. In other words, we can probably detect only the relative motions of two material systems with reference to each other and not their absolute 1The original experiment was made by Michelson and Morley in 1887 and repeated most recently by Morley and Miiller, Phil. Mag., vol. 9, p. 680, 1905. 2 Rayleigh, Phil. Mag., vol. 4, p. 678, 1902. 3 Brace, Phil. Mag., vol. 7, p. 317, 1904. *See the admirable book by Lorentz, entitled ‘“‘ The Theory of Electrons,’ and published by Teubner in Leipzig, 1909. 5’ Trouton and Noble, Phil. Trans., vol. 202, p. 165, 1903. See also Langevin, Comptes Rendus, vol. 140, p. 1171, 1905. 228 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. movement with reference to a supposed stationary ether. This novel hypothesis was announced in its most general form for the first time by Einstein,’ who named it the principle of relativity. Starting with this simple principle, Einstein modified slightly the transformation of Lorentz, giving to it a physical basis of very great generality and gathering all the conclusions resulting from it into a group of per- fectly consistent formule. We will not state here all the physical and philosophical conse- quences of this theory of relativity. We will note only the absolute character assumed by the two fundamental postulates of this theory: First, the ether is immovable and penetrates matter perfectly ; second, the velocity of light is an absolute invariant and represents a su- perior limit which‘no other velocity can exceed (whether for matter in motion or the propagation of waves). The theory has been fur- ther developed (principally by Germans) by Einstein (1905-1912), Minkowski (1905-1908), Planck (1907-8), Born (1909), Som- merfeld (1910), Laue (1911), etc. The various points of view which these physicists have adopted are too numerous to be given here in detail; some have tried to put the transformations of Lorentz into more geometrical and comprehensive form (Minkowski) ; others have deduced the kinetic consequences of the principle, either for a moving point (composition of velocities according to Sommerfeld) or for a solid body in rotation (Born, Laue, etc.). Difficulties and complications quickly arise as soon as the motion of uniform trans- lation originally supposed is departed from and these difficulties have not yet been overcome. The total absence of any experimental basis or confirmation of these later developments deters us from further discussion. We will stop a moment only on one of the most para- doxical consequences of the principle of relativity which will bring out the difficulties which the theory encounters and rebut the abso- lutism of the principles which it uses as bases of the physical sciences. At the start Einstein? showed that if the energy of a sys- tem increases by the amount /, the principle of relativity requires that its mass increases at the same time by E/V?. Only on this con- dition can the principle of the conservation of the movement of the center of gravity as well as the new system of mechanics be main- tained. Accordingly, mass and energy are not really distinct; the principle of the conservation of mass is inseparable from the prin- ciple of conservation of energy. This result, however strange, is nevertheless consistent in itself. Einstein himself, basing his deductions on this consequence, tried to bring back to the principle of relativity the absolute value which 1 Hinstein, Annalen der Physik, vol. 17, p. 902, 1906. 2 Binstein, 1. c. and Annalen der Physik, vol. 20, p. 627, 1906; vol. 23, p. 578, 1907, etc. t DEVELOPMENTS IN ELECTROMAGNETISM—BLOCH. 229 had been attributed to it since 1905.1. He has tried to include in the electromagnetic synthesis of the universe the phenomenon of gravity, hitherto so rebellious against all our efforts at explanation. He noted that a uniform gravitational field of constant accelera- tion, y, is equivalent to a medium free from gravitation in which the reference axes are supposed acting with a uniform acceleration —y. Next we must generalize the principle of relativity and pass from the case considered until now of a uniform velocity of trans- lation to that of a uniform acceleration. In the earlier case we were led to attribute to energy a mass m=//V?; now, if we wish to preserve the principle in its entirety we must attribute to the same energy the weight my. As a particular case, radiant energy, light, must have weight; a beam of hght must then be deviated by the masses close to which it may pass. Einstein’s calculation showed, for example, that the angular distance between a star and the center of the sun must be decreased by about one second when the star appears close to the sun. The measurement could be attempted at a total eclipse of the sun. There is no need of calling attention to the strangeness of these conclusions. The important thing from a philosophical point of view is that we are obliged to give up the absolute invariability of the velocity of light, V, considered at the start as an unassailable axiom. This invariability is only true in a system where the gravi- tational potential ¢ remains constant. For variable potentials the velocity of light must. vary according to the formula, V=V, (1+0/V?). So it is only in the case of uniform motion of translation that the transformation of Lorentz represents the phe- nomena of a system in movement. In the more general case the group of transformations is more complicated and as yet undeter- mined ; the equations to be substituted for those of the classic elec- tromagnetism are also undetermined. This new point of view of Einstein has at least one incontestable utility: It makes us realize that the postulates which were at the basis of the earlier principle of relativity (the invariability of V, etc.) are perhaps only approximate affirmations, susceptible of modi- fication, and not first truths. It has led us from metaphysics to physics. And since the discussion became opened anew concerning the foundations proposed by Einstein we will not be surprised to find that Max Abraham, adopting this new conception of mass and weight, has developed a new theory of gravitation, different in many respects from that of Einstein. Abraham? renounces the generaliza- 1 Winstein, Jahrbuch der Rad. and Hlectronik, vol. 4, p. 4; Annalen der Physik, vol. 35, p. 898, 1911, etc. *Max Abraham, Phys.+Zeitschr., vol. 13, No. 1, 1912; Annalen der Physik, vol. 38, p. 1056, vol. 39, p. 444, 1912; Nuovo Cimento, January, 1913. 230 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. tion of the principle of relativity in the case of acceleration. Then considering that as a whole the principle of relativity has failed, he keeps the Lorentz transformation only for very small changes in the variables. Considerable discussion has passed between him and Einstein, but we will not follow the details.* Admitting that these theories will have a lasting effect upon science, in the future new experiments will be required and a more powerful theoretical effort than that of the past. We will close our exposition of this question by citing the opinions of several skeptical physicists who, from the beginning, have found the postulates upon which the theory of relativity rests too absolute and to whose voices we are now beginning to listen. The ether in the principle of relativity has been emptied little by little of all its physical properties; it is represented now only by a system of mathematical equations, those of Maxwell-Lorentz, and a number, the velocity of light. It remains as the vehicle of radiant energy without our questioning how. Ritz,? following to the logical conclusions such notions, proposes to renounce wholly the hypothesis of an ether and to return to a theory very close to the old one of emission. According to him, we need not speak of electric and mag- netic fields, but only of electric charges acting upon each other. We thus return to action at a distance but taking into account the finite velocity with which such action takes place. Consequently it is necessary to throw away the partial differential equations of the electric field and replace them with integrals (retarded potentials). There is thus introduced an irreversibility of which the former equa- tions could not take account. Mass at great velocities will remain constant, but the force will vary. We thus arrive at another system of mechanics. Against these new conceptions, the development of which was unfortunately interrupted by the death of the author, there are grave objections which have so’ far kept the majority of theorists from adopting them, although they are perfectly consistent among themselves. Brillouin,? on the other hand, makes the ether more substantial than has been customary. There must be, according to him, a drastic revision of the hypotheses relative to it. For example, its absolute immobility, perfect permeability, homogeneity, isotropy, and the in- variability of the velocity of light. Those upholding the principle of relativity bave themselves commenced to attack the last postulate, as we have just seen. Now it will be the turn of the other properties. We may come, through the increasing acuteness of our powers of 1 Hinstein, Annalen der Physik, vol. 38, p. 355 and 1059, 1912; vol. 39, p. 704, 1912. 2 Ritz, Annales de chimie et de physique, vol. 13, p. 145, 1908. 3 Brillouin, Scientia, vol. 13, p. 10, 1913. See the Revue générale des Sciences, Mar. 80, 1913, p. 214. DEVELOPMENTS IN ELECTROMAGNETISM—-BLOCH. ok analysis, to admit, to a closer degree of approximation, that the ether, at least slightly, is similar to ordinary matter, that it may propagate a disturbance with a velocity greater than that of light, that it does not remain perfectly stationary when matter traverses it, etc. New experiments must be added to the purely electro-optic ones of Michel- son, Rayleigh, Brace, and Troughton before we will be able to build these theories. Ill. ELECTROMAGNETISM AND RADIATION. The difficulties just described are not the only ones which the modern theory of electromagnetism encounters. Perhaps the gravest ones arise in adapting it to the experimental facts of radiation, We know that thermal radiation in equilibrium in a constant-temperature chamber, and called “black radiation,” has a density independent of the particular body producing it. It is a function only of the wave- length } and the absolute temperature 7. Our theoretical knowl- edge of this density, w,, is expressed by the well-known laws of Kirchoff, Stefan-Boltzmann, and Wien. Our experimental knowl- edge is expressed by the formula of Planck, ae This equation satisfies not only the three theoretical laws but also corresponds to the observed distribution of energy in the spectrum of a black body. This formula reduces for large values of AZ to the earlier one of Rayleigh, UW =, /C,- T/A: Now, the electromagnetic theory seems to lead almost inevitably to Rayleigh’s formula for all wave-lengths in flagrant contradiction to experimental facts. The second formula, indeed, does not give a maximum to the radiation distribution curve and makes the total radiation infinite. This consequence, which the researches of Lord Rayleigh? and Jeans* made extremely probable, has been ren- dered certain by those of Lorentz.* According to the latter’s re- 1 These laws rest only on the Doppler-Fizeau principle, thermodynamical reasoning and the pressure of radiation, principles which may be held as well proven if not as ex- perimental facts. 2 Rayleigh, Phil. Mag., vol. 2, p. 539, 1900. * Jeans, I. c., vol. 10, p. 91, 1905; vol. 17, p. 229, 1909; vol. 17, p. 773, 1909; vol. 18, p. 209, 1909. *Lorentz, Revue générale des Sciences, p. 14, 1909; La théorie du rayonnement (The theory of radiation), Rapports au Congrés de Bruxelles de 1911, publiés par Langevin and de Broglie. 232 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. searches, the most general equation of an electromagnetic system, based upon the ether, electrons, and matter, by a suitable choice of parameters can be reduced to the Hamiltonian form of the equations of mechanics. The application of the methods of probability and statistical mechanics, especially the theorem of Liouville (which is a consequence of the Hamiltonian form), leads us, then, to consider as applicable to the ether the theorem of the equipartition of energy which also brings us out with Rayleigh’s formula. In order to escape from this blind alley and obtain the earlier formula, Planck invented the hypothesis of the discontinuity of en- ergy or quanta. According to this hypothesis, the molecular resona- tors can not exchange energy with the surrounding medium except in whole multiples of the same elementary quantity (quantum), Ay, an amount proportional to the frequency of the resonator. The con- stant A would be a universal constant. We will not explain here the various forms given to the theory by Planck himself, Sommerfeld, Einstein, H. Poincaré, and others (see articles cited, note 4, p. 231). We will pass over all the consequences which have been deduced from this hypothesis (theory of specific heats by Einstein, etc.), except those which are purely electromagnetic.’ Tt appears that we need not give up for the free ether the equations and ordinary laws of electromagnetics or the dynamics of the free electron. The modification of the electromagnetic theory which we must make, if necessary, relates only to the relations between matter and the ether; that is to say, with regard to electrons not free, to emissions and absorption of energy, or perhaps to emission alone, which must then be considered as discontinuous. Brillouin® thinks that there is a loophole of escape: Planck’s theory rests upon an arbitrary hypothesis with regard to strictly monochromatic resonators having very little physical basis. In giving these up, the complication of the reasoning rapidly increases, but Brillouin thinks that we can probably come out with Planck’s formula without recourse to quanta. The result would, however, be inconsistent with the general theory of Lorentz previously men- tioned. Possibly we may hope to reach more precise knowledge of the mechanism of absorption about which we know practically noth- ing, and thence get a loophole for escape. This doubtless will hap- pen in the future. There is another domain than that of radiation, wherein the elec- tronic and quanta theories are clearly inconsistent, that of the prop- erties of the metals. According to the electronic theory, the thermal and electrical conductivities of the metals, as well as many other of 1 See the recent article by J. Perrin in the Revue for Nov. 15, 1912. 2These consequences have been resumed in a notable course of lectures given this year at the Collége de France by Langevin. 8 Brillouin, Comptes Rendus, vol. 156, pp. 124, 301, 1913. DEVELOPMENTS IN ELECTROMAGNETISM—BLOCH. 250 their properties, are due to the motion of free electrons. We may, indeed, derive thus the law of Wiedemann and Franz. Electrons should therefore play an important part in the specific heats of the metals. But, according to the theory of quanta, the specific heat is uniquely related to the uncharged atomic resonators (Hinstein). This accounts for the behavior of the specific heats at low tempera- tures. But the quanta theory has nothing to offer as to the thermal and electrical conductivities. The discordance is, however, decisive. It is perhaps premature to try to reconcile matters until measures of the thermal conductivities at low temperatures have been made, com- parable with the excellent ones on the electrical conductivities made by Kamerlingh Onnes? at the temperature of liquid air and hydrogen. IV. THE MAGNETON. The electron seems to have definitely become one of our physical properties. P. Weiss’ has for several years, and with increasing success, tried to introduce an element of magnetism, the magneton, bringing to bear upon it an imposing mass of experimental results. He started from the theory of dia- and para-magnetism built by Langevin.* In that theory diamagnetism is explained by the de- formation of the intra-atomic electronic trajectories under the influ- ence of an exterior electric field paramagnetism results from the existence of a molecular magnetic moment of certain substances. Weiss has elaborated this theory so as to include ferromagnetism by means of a supplementary hypothesis, that of molecular magnetic fields proportional to the magnetizing force. This idea of an electric field is not new. Through it Ritz* developed his beautiful theory of the structure of the series of certain spectrum lines and the Zeeman effect. It led Weiss to formule which are well substantiated by ex- periment not only in the legitimate field of electromagnetism (the variation of the Curie constant with the temperature), but also as to the specific heats of ferromagnetic bodies. It was while looking for such precise experimental confirmation that Weiss was led to the theory of the magneton. The measure of the absolute value of the atomic magnetic moments of iron and nickel at the temperature of liquid hydrogen, made in collaboration with MKamerlingh Onnes, led at the start to numbers 12,360 and 3,370, which divided, respectively, by 11 and 3 lead prac- tically to the same quotient, 1,123.5. For cobalt the corresponding number was later found to be very close to 9X1,123.5. For the 1 With regard to all these questions which we can not stop to more than sketch, see the lecture which we delivered before the Société de physique in December, 1911, upon the electron theory of metals and also the book which we have several times cited on the Theory of Radiation. 2 Weiss, Journal de physique, pp. 900, 905, 1911. ’ Langevin, Annales de chimie et de physique, vol. 5, p. 70, 1905. * Ritz, Annalen der Physik, vol. 25, p. 660, 1908. 234 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. molecule of magnetite the results were more complex and must be divided by 3 to compare them with the atom of iron. These also led to whole multiples of the same number, the factor of propor- tionality changing abruptly at certain temperatures as if the atom of iron underwent corresponding alterations. The number 1,235, of which all the atomic magnetic moments are multiples, will be called the magneton-gram, and its quotient by the Avogadro num- ber (the number of atoms per gram-atom) is the magneton, 16.4<10-**. The properties of a ferromagnetic body are then well explained by supposing that the magnetic moments of their atoms are simple multiples of a magneton. Magnetism will then have a granular structure like electricity. Interesting confirmations have been made of this theory through measures of various experimenters upon paramagnetic salts or, in- deed, upon other bodies. The numbers of Pascal* and those of Mlle. Feytis? are in qualitative and quantitative accord with the hypothe- sis of the magneton. As these numbers were calculated with refer- ence to water as a standard, an exact knowledge of the diamagnetic constant of water became necessary. Its measure is difficult and has led to discrepant results. It has been remeasured separately by Séve® and by P. Weiss and Piccard,* who have reached concordant results close to 0.7210 at 20° C. The theory of the magneton thus has had the merit of fixing definitely this important constant. - We are obliged to admit, however, that for ferromagnetic bodies the atom does not possess a unique magnetic moment, but has a cer- tain number of different values according to the temperature and the chemical compound into which it enters. All these values, how- ever, have integral ratios. The actual existence of the magneton has been demonstrated in the atoms of iron, nickel, cobalt, manganese, vanadium, calcium, mercury, and uranium. We therefore seem to have here a real, very general constituent element of matter. We may therefore think of adding the magneton to the other known fundamental elementary bodies. The attempt made by Langevin ® to deduce the magneton from the quantum of Planck will doubtless serve as a stimulus in this direction. Vy. THE PRODUCTION AND NATURE OF GASEOUS IONS. We will not discuss here the simple, ordinary ions, such as origi- nate from the X rays, radium, the Hertz effect, etc. For several years the accepted theory (Langevin, J. J. Thomson, Townsend, and others) was this: the negative electron, torn from a molecule by the 1 Pascal, Ann. Ch. Phys., vol. 16, p. 531, 1909; vol. 19, p. 5, 1910. 2Mule. Feytis, Comptes Rendus, vol. 152, p. 708, 1911. 8 Séve, Ann. Ch. Phys., vol. 27, p. 189, 1912. 4 Weiss and Piccard, Comptes Rendus, vol. 155, p. 1234, 1912. 5 Langevin, Rapport 4 la Conférence de Bruxelles, 1911. DEVELOPMENTS IN ELECTROMAGNETISM—BLOCH. 9385 ionizing force, surrounds itself with a cortege of neutral molecules; the residual positive atomic ion does likewise. Thus originate the ordinary positive and negative ions. They are «characterized by their mobility A, coefficient of recombination «, and diffusion D. At very low pressures and at high temperatures these assemblages are dissociated little by little to the primitive charged center., We will see that some modification of these ideas will be necessary. (1) Along the line of theory since the fundamental work of Langevin (Annales Ch. Phys., 1905) several new attempts have been made to explain the order of magnitude of the mobilities and their variations. Among these we should specially mention those of Sutherland, of Wellisch,2? and of Reinganum.? Sutherland, es- pecially, departing from the hypothesis of molecular agglomera- tion, supposes that an ion is identical with the electron or the primitive atom-ion; its velocity is modified and retarded by the electric action exercised upon the neighboring ions or the molecules polarized by its approach. An apparent viscosity is thus created which explains very well the results of Phillips (see further on) upon the variation of the mobility with the temperature. The actual theory is not unlike that which led Sutherland to his well-known formula for the variation with the temperature of the viscosity of a gas. It will be perhaps convenient to use the conventions of the older theory, considering the ions as assemblages in perpetual process of formation and disintegration in a kind of dynamical equilibrium; the charged center will then be in turn free and loaded with neutral molecules. We will see that a greater part of the experimental data makes such a convention almost necessary. (2) With a view to furnishing useful material for the theoretical developments, many measures have been made upon the mobility, the rate of recombination, and the diffusion at various temperatures and pressures. We will mention the measures of Phillips‘ (varia- tion of & and a with the temperature), Kovorik,> Tood,’ Dempster? (variation at K at high and low pressures), Sales* (variation of D with the pressure). These measures show that ionic agglomerations disintegrate faster at low pressures and high temperatures in the case of negative ions and tend for both positive and negative ions to revert to the primitive state. This is in accord with the measures 1 Sutherland, Phil. Mag., vol. 18, p. 341, 1909. 2 Wellisch, Phil. Trans., vol. 209, p. 249, 1909. 3 Reinganum, Phys. Zeitschr., vol. 12, pp. 575 and 666, 1911. 4Phillips, Proc. Roy. Soc., 1906, and vol. 83, p. 246, 1910. 5 Kovorik, Phys. Rev., vol. 30, p. 415, 1910; Proc., vol. 86, p. 154, 1912. 6 Tood, Radium, p. 113, 1911; p. 465, 1911. 7 Dempster, Phys. Rev., vol. 34, p. 53, 1912. 8 Sales, Radium, p. 59, 1911. 236 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, made upon flames by Moreau,! Lusby,? H. A. Wilson, and others.® The negative ions in flames appear to differ little from corpuscles and are scarcely loaded in their accidental encounters with molecules. The positive ion has a size of the order of magnitude of a free atom- ion and often appears to be formed of an hydrogen atom, more rarely of a metallic atom in certain flames colored by salts. (3) It is mostly with ionization at ordinary temperatures that the newer results have been obtained. The study of ionized gaseous mixtures was first undertaken by Blanc* and by Wellisch. Accord- ing to them an ion produced in a gas A and then transported into another gas B, assumes a mobility characteristic of the gas B. This agrees with the idea of temporary agglomerations constantly de- stroyed and built up again. Blane carried out his experiment with ions formed in carbonic acid gas and then transported into air. Wellisch created his ions in CH,I of CCl, and then transported them into hydrogen. According to him the ionization in hydrogen is enormously increased by traces of CH, whereas the mobility changes only slightly. It looks as if the heavily ionized molecules of CH,1 transfer their charges to the hydrogen molecules. This is a re- markable property belonging to certain ions. The same experi- menters, as well as Lathey,® Tyndall,” and others, have studied with precision the influence of traces of a foreign gas upon the mobility of ions. According to Blanc a small amount of aqueous vapor diminishes the mobility of the negative ion and increases that of the positive ion in air and in carbonic acid gas (450 and 490 C. G. S. for air instead of 380 and 600). The same occurs with aleohol vapor. The molecules of water and alcohol without doubt remain longer associated with the charged nucleus than those of air, carbonic acid gas, or hydrogen. Just the opposite is the case with the molecules of CH,I, CCl,, etc. From this we see also that in certain gases the positive ions finally surpass the negative ions in mobility. This, for instance, happen with chlorine. The most remarkable fact in this connection was noted by Franck.® Working upon argon he found normal mobilities (of the order of 1 cm. in a 1 volt-cm. field) for the positive ions, while the negative ions had mobilities of more than 200 em. and behaved as corpuscles free from corteges of molecules during the major part of their courses in the gas. This enormous mobility diminishes very rapidly 1 Moreau, Comptes Rendus, vol. 148, p. 342, 1909; Radium, p. 70, 1910. 2Lusby, Proc. Cambr., vol. 16, p. 26, 1911; Phil. Mag., vol. 22, p. 775, 1911. 3H. A. Wilson, Phil. Mag., vol. 21, p. 711, 1911. 4Blanec, Journal de physique, vol 7, p. 838, 1908. 5 Wellisch, Radium, p. 241, 1909, and 1. ¢. 6 Lathey, Proc. Roy. Soc., vol. 84, p. 173, 1910. 7Tyndall, Nature, vol. 84, p. 530, 1910. 8 Franck, Verh. Deutsch. Phys. Gesellsch., vol. 12, p. 291, 1910. ‘ DEVELOPMENTS IN ELECTROMAGNETISM—BLOCH. pra under the least trace of oxygen; it is brought down to 1.7 cm. by 1.5 per cent of oxygen. The tendency to associate with the oxygen molecules is therefore much greater than with the argon atom. Nitrogen shows a behavior analogous to argon. (4) The study of the charge carried by the ions has led also to important results. The method used for measuring the charge e is based upon the condensation of water-vapor upon the ions (Townsend and J. J. Thomson) and has been further perfected by Millikan’? and his pupils. By means of a microscope a single drop of oil or other material charged by the ionized gas is observed be- tween the horizontal plates of a condenser. Its rates of rise or fall due to the combined electrical and gravitational fields are followed, and from these rates the charge e may be computed. Thus by ob- serving the sudden changes in the rates the new charges can be noted as they are added or taken away from the drop. It is found that these modifications of the charge of the drop always occur in whole multiples of the same elementary charge, e. The mean of the num- bers found for e was 4.8910-"° electrostatic units. This number accords with that deduced by Rutherford from his measures with the rays although J. Perrin found somewhat smaller values from his study of emulsions and of the Brownian movement. An important fact was noted by Townsend? and his students: Ions of double charge, 2e, or multiples of this, were found in ionized gases. - This was noted in the experiments made in 1899, by means of which Townsend, measuring the diffusion coefficient D by a method using a gaseous current and comparing it with the mobility % was able to determine the product Ve of the charge of the ion by the Avogadro’s number (the number of atoms per atom-gram). This was a static method and permitted the evaluation directly of the quotient 4/D which equals the product Ve. This result was dependent upon the method of ionization used. At mean pressures and with the a rays from radium in air or the secondary rays due to X rays produced upon polished brass in hydrogen or oxygen, slightly moist, ions of opposite sign were both found to give nearly the value 1.2410". However, if the secondary rays are produced in air at a sheet of brass, oxidized or covered with vaseline, or in other gases (hydrogen, oxygen, carbonic acid) upon the same strip polished and covered vaseline, the value of Ve is much greater for the positive ions. It may be found as high as 2.410!°. We conclude therefore first, that - certain positive ions carry a charge 2e; secondly, that such ions are produced by the more penetrating secondary rays which are not 1 Millikan, Radium, p. 345, 1910; Phys. Rev., vol. 32, p. 349, 1911. 2 Townsend, Proc. Roy. Soc., vol. 80, p. 207, 1908; vol. 81, p. 464, 1909; vol. 85, p. 25, 1911; Haselfoot, Proc. Roy. Soc., vol. 82, p. 18, 1909. 238 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. absorbed by the vaseline. The existence of these polyvalent ions has been confirmed by Franck and Westphal, who returned to the older method, using a gaseous current and devised by Townsend, in which K and P are separately measured. With X rays the proportion of polyvalent ions is about 1/10; with the @ rays of polonium of the 6 rays of radium there seem to be no polyvalent ions. Millikan and Fletscher? do not agree with these conclusions, basing their ob- jections upon the method of drops earlier described. But the earlier physicists maintain their interpretation, which also seems to be in good accord with the results from other methods (multiple charges of the « rays from radium, of the canal rays, the positive rays of vacuum tubes, according to J. J. Thomson, Gehrke, and Reichenheim and others). However, the question must seem at present unsolved. Very re- cently, Langevin and Salles,? measuring the ratio K/D by a new direct method, have concluded against the existence of polyvalent ions in the ionization by X rays. We must therefore still leave the ques- tion open. (5) Finally, we must note the remarkable experiment by which C. T. K. Wilson‘ has enlightened us as to the mechanism of ioniza- tion. Continuing his celebrated experiments on the condensation of water vapor on ions, he succeeded in seeing and photographing the trail of ions, produced in a gas by an angle « or @ particle from radium or a very narrow pencil of X rays. His admirable photographs themselves alone can give an idea of all of which we can learn from them. Upon them we see the 2 and 8 particles following their rectilinear trajectories; we learn that the X rays do not ionize directly but by the secondary rays which they tear from the molecules encountered in the gas, etc. We find also a direct verification of the hypothesis advanced by Langevin and put to experimental test by Moulin® in order to explain the “initial re- combination” discovered by Bragg. According to the latter, the saturation current of a gas ionized by « rays is much more difficult to obtain than when X rays are used. This is due, not to an “ initial recombination” between the positive atom ions and electrons just liberated, but to a localization of the ions along the path of the a particles; a saturation current is indeed much easier to obtain when the field is perpendicular to the radiation than when parallel. 1 Franck and Westphal, Verh. der Deutsch. Phys. Ges., vol. 11, pp. 146 and 276, 1909. 2Millikan and Fletscher, Phys. Reyv., vol. 32, p. 239, 1911, and Phil. Mag., vol. 21, p. 753, 1911. See also Townsend, Phil. Mag., vol. 22, p. 204, 1911; Franck and West- . phal, Phil. Mag., vol. 22, p. 547, 1911. 3 Langevin and Salles, Société de chimie physique, February, 1913. 4 Wilson, Proc. Roy. Soc., vol. 85, p. 285, 1911; Radium, January, 1913. 5 Moulin, Radium, p. 350, 1910. —— DEVELOPMENTS IN ELECTROMAGNETISM—BLOCH. 239 VI. PHOTOELECTRIC EFFECT. (HERTZ AND LENARD EFFECTS.) Light, and especially ultra-violet light, discharges negatively elec- trified bodies with the production of rays of the same nature as cathode rays. Under certain circumstances it can directly ionize gases. The first of these phenomena was discovered by Hertz and Hallwachs in 1887. The second was announced first by Lenard in 1900. Perhaps on no subject is the literature of the day greater and more contradictory, so we will note only a few of the recent results upon which the bulk of the work has been done. (1) With regard to the Hertz effect, the researches from the start showed a great complexity of the biicHomenbe of photoelectric fatigue—that is, the progressive diminution of the effect observed upon fresh metallic surfaces. According to an important research by Hallwachs, ozone plays an important part in the phenomenon. However, other elements enter such as oxidation, the humidity, the mode of polish of the surface, etc. We are not even sure that the fatigue is absent ina vacuum. Eugene Bloch? insists that we should work with an exciting radiation of definite wave-length since the fatigue varies from one wave-length to another. He also showed that in certain instances there is an acceleration of the effect which has been refound by various workers. A, great many experiments have been made in a vacuum. Some were undertaken to study the Hertz effect at the rear surface of a strip traversed by the light, an effect perhaps greater there than at the front surface (Stohlmann, Kleemann, and others). Other ex- perimenters have shown a selective effect in the case of certain metals; for instance, with the alkaline metals, according to Pohl and Pring- scheim,’ there are maxima of exciting power at wave length 0.300 p. for sodium, at 0.436 % for potassium, and at 0.890 p for a liquid alloy of potassium and sodium. The general exciting power increased regularly toward the smaller wave lengths. Several workers have also endeavored to extend the photo-electric sensitiveness of photo- electric cells into the infra-red (Elster and Geitel) or to utilize them for photophony (Bloch). However, the greatest effort has been spent in order to find out in vacuum the variation of the initial velocities of the photo-electric electrons with the wave length. This problem has a great theoretical interest, and the simple laws stated by Lenard since 1900 for the ensemble of radiation emitted should be studied separately for each wave length of the exciting radiation. According to Lenard, the total number of electrons emitted is proportional to the intensity of 1 Hallwachs, Annalen der Physik, vol. 23, p. 459, 1907. 2 Bloch, Radium, vol. 23, p. 125, 1910. Pohl and Pringscheim, Verh. der Deutsch. Phys. Ges., vol. 12, pp. 215, 349, 1910. 240 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. the incident light, but their velocity is independent of it, as well as of the wave length for any given metal. This odd result does not at all agree with the quanta hypothesis which, according to Einstein, leads to a linear variation of the initial energy mv?/2 with the fre- quency. We may further in our measures replace the initial velocity by the maximum positive potential V which the metal can take under the influence of the rays (that is, the potential of the stoppage of the electrons). The first measures made upon this matter by Laden- burg?! showed an increase of the initial velocity with the exciting frequency. Taken up by Ladenburg and Marlay,? Hull,? Hughes,* Richardson,’ and others, the experiments have confirmed, although not without disputeand difficulty,the qualitative resultof Ladenburg and apparently the theoretical law of variation due to Kinstein. Cer- tain writers contest this last deduction and claim a parabolic in place of a linear law of variation. Our own unpublished experiments com- pleted upon this question lead us to reserve our decision, because of the smallness of the ranges of wave lengths studied by all these experimenters. It will be necessary to take up with quartz appa- ratus this question, working with the alkaline metals from the visible spectrum way up to the extreme ultra-violet. This is the only pro- cedure which will allow a real experimental test of the theory of quanta. We will close with the results obtained by Millikan’ and his pupils, who have found in certain cases abnormally high initial velocities. It looks as if there might be some experimental error due to the mode of production of the discharge by the ultra-violet light and the influence of the electric waves from the source upon the measuring apparatus. (2) The discovery of the ionization of gases by ultra-violet light was made by Lenard in 1900. As the effect was produced across several centimeters of air and made very great positive and small negative ions, it was natural to interpret the phenomenon, as did J. J. Thomson, as an Hertz effect upon the solid or liquid particles present in the gas. The researches of Langevin and those of Eugene Bloch ® have shown, indeed, that the greater part of the Lenard effect is certainly due to this cause. The Lenard effect upon the gas itself nevertheless does exist. Re- found by J. J. Thomson® and then more decisively by Palmer,*° it 1 Ladenburg, Phys. Zeitschr., vol. 8, p. 590, 1907. 2 Ladenburg and Markav, Phys. Zeitschr., vol. 9, p. 821, 1908. 8 Hull, Phys. Zeitschr., vol. 10, p. 587. 4 Hughes, Phil. Mag., vol. 21, p. 393, 1911; Proc. Cambr., vol. 16, p. 167, 1911. 5 Richardson, Phil. Mag., vol. 24, pp. 570, 575, 1912. 6 Kuntz, Cornelius, Phys. Review, 1910 and 1913. 7 Millikan and Wright, Phys. Review, January and February, 1911. 8 Bloch, Radium, p. 240, 1908. ® Thomson, Proc. Cambr., voi. 14, p. 417, 1907. 10 Palmer, Nature, vol. 77, p. 582, 1908; Phys. Rev., p. 1, 1911. DEVELOPMENTS IN ELECTROMAGNETISM—BLOCH. et has already been considerably studied and shows very different char- acteristics than those at first attributed to it by Lenard. It seems to be produced exclusively by the Schumann or extreme ultra-violet rays of wave length less than 0.180 p. These rays will not pass through air although they will through fluorite and partly through quartz. It produces small ions of both signs, neutral centers, large ions, and ozone. It is extremely sensitive to minute traces of im- purities in the gas, traces which can not be detected by other means. It can be distinguished from the Hertz effect and become very much greater. All these conclusions are drawn from the researches of Hughes,! Cannegieter,? Lenard and Ramsauer,* and Leon and Eugene Bloch.t| The latter have shown also that the radiation transmitted by quartz and coming from a mercury arc ionizes the air feebly in the neighborhood of the are and seems consequently to emit a small amount of Schumann rays. In place of the usual source of Schu- mann rays, a hydrogen tube furnished with quartz windows, Lenard and Ramsauer used a very powerful spark between electrodes of aluminum. Then the ionization takes place even through air and quartz and the experimenters attribute it to rays of wave length less than 0.1 py, the smallest ultra-violet rays known and which were discovered by Lymann. As no measure of these wave lengths were made, it seems as probable that the effect is due to ordinary Schu- mann rays which have been partially transmitted by media generally opaque to them because of the great original intensity of the light. This question remains to be studied as well as the Lenard effect in general the knowledge of which is yet very limited despite the great number of interesting problems connected with it. 1 Hughes, Proc. Cambr., vol. 15, p. 483, 1910. 2 Cannegieter, Proc. Amst., p. 1114, 1911. 8’ Lenard and Ramsauer, Sitzungsber. Heidelberg, 1910-1911. *Leon and Eugene Bloch, Comptes Rendus, vol. 155, pp. 9038, 1076, 1912. 44863°—sm 19183——16 esa dt age Fak Birk hale bin WIRELESS TRANSMISSION OF ENERGY.? By Exinvu THOMSON. It will be my purpose in the present discourse to outline the gen- eral nature of wireless transmission and to indicate its relationship to transmission by wire. It will also be my object to show why the wireless energy sent out follows the curvature of the earth and to explain other features which to many have been more or less puz- zling. In short, I desire to present in simple terms a view of the nature of such wireless work, so that anyone reasonably informed about electrical actions can obtain, as it were, a mental picture of the process. I may here state the fact that perhaps one of the earli- est experiments bearing on wireless transmission was made in com- pany with Prof. E. J. Houston, while we were both teachers in the Central High School in Philadelphia. This old experiment to which I refer was made about the latter part of 1875, and briefly described in the Franklin Institute Journal early in 1876. It con- sisted in using an induction coil which would give a spark length of several inches, then known as a Ruhmkorff coil, the coil resting on the lecture table, one terminal of the fine wire or secondary of which was connected to a water-pipe ground, while the other was con- nected by a wire 4 or 5 feet long to a large tin vessel supported on a tall glass jar, insulating the tin vessel from the lecture table. The coil had an automatic interrupter for the primary circuit, and when in operation the terminals of the secondary were approached so that a torrent of white sparks bridged the interval between them, the gap being about 2 inches or so in length. Figure 1 shows this arrangement. When the coil was worked in this way, it was found that a finely sharpened lead pencil approached to incipient contact with any metallic object—such as door knobs within the room and outside thereof—would cause a tiny spark to appear at the incipient contact between the pencil point and the metal. This, of course, . was not a very delicate detector, but was improved, as in figure 2, by putting two sharpened points in a dark box, a device due to 1 Lecture by Prof. Thomson, printed after revision by the author, by permission of the National Electric Light Association, New York, 243 244 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, Edison. One or both points were adjusted so as to make incipient contact, and the tiny spark observed between the points was an indi- cation of a shock, commotion or wave, electrical in its character, in the ether surrounding the tin vessel mounted on the glass jar. The tests for detecting the impulses were carried on not only in rooms on the same floor, but on the floor above and on the floor above that, and finally at the top of the building, some 90 feet away, in the astronomical observatory. Metallic pieces, even unconnected to the ground, would yield tiny sparks, not only in the basement of the building, but in the highest part, with several floors and walls inter- vening. I mention this old experiment particularly because it has in it the elements, of course in a very crude form, of wireless trans- mission, the wire and tin vessel attached to one terminal of the coil being a crude antenna with its spark-gap connection to ground, as afterwards used in wireless work by Mar- coni, and it also shows a rudimentary receiver or detector, a metallic body ar- ranged in connection with a tiny spark gap, so that electrical oscillations in such body would declare themselves by a faint spark at the gap. It was understood by us at the time that after each discharge of the coil there was, as it were, a shock, or wave in the ether consisting of a quick reversed electrical condition, and it was even imagined that there might be in this process the germ of a system of signaling through space. This old work was almost forgotten when it was recalled by the later work of Hertz, about 1887, who demonstrated by suitable electrical apparatus that waves of the general nature of light or heat could be generated, which waves are transmitted with the velocity of light, 186,000 miles per second, and that by suit- able resonators or detectors these waves could be made to declare themselves by tiny sparks. The Hertzian oscillator was, as it were, an electrical tuning fork, having an actual rate of vibration peculiar to itself and dependent on its form and dimensions. It was fed with energy from an induction coil and across its spark gap an oscillating discharge took place, which, at each impulse, died out like the dis- charge of a condenser, but during this, discharge it electrically WIRELESS TRANSMISSION OF ENERGY—THOMSON. 245 stressed the ether in one and the other sense, so that an electrical wave was radiated in certain directions from the oscillator. It was found that these waves could be refracted, reflected, and polarized, and, in general, dealt with as extremely coarse light or heat waves. We shall refer to these, however, farther on. The general result, however, of the Hertzian experiments was to connect electrical waves in the ether surrounding the apparatus with the hght and heat waves and prove the identity of the two kinds of radiation, the differences being only those of wave length or pitch. Since the Hertzian waves were sent out from the Hertzian oscil- lator in substantially straight lines, and since in the early days of wireless telegraphy it was common to regard wireless waves as of the same nature or as almost identical with Hertzian waves, the fact that the wireless waves were found to follow the curvature of the earth became a difficulty to be ex- Fig. 4 plained. Speaking FiQ. 3 ee for myself, I have — iN sa RUM R BERD MM never found the diffi- =\! feat | | t Fry lyylty\ culty to exist. There man ea | is really no reason why the waves should not follow the curva- ture of the earth, as it will be one of my purposes to show. We will, however, ap- proach the conditions of wireless somewhat gradually. We will first consider an ordinary wire transmission of the sim- plest type. Let us assume a line of wire, as in figure 3, insulated and connected to one terminal of the battery while the other terminal is earthed or grounded. A simple telegraph system on open circuit would represent this arrangement. The only effect is that the battery supplies a small charge to the line, producing a potential difference between the insulated line and the earth, assuming, of course, that there is no leakage of any kind to disturb the conditions. As soon as the charge is established in the line at the full potential of the battery, which, in ordinary cases, would take place within a very small fraction of a second, a steady or static condition is reached, which might. be indicated by electrostatic stress lines drawn from the wire to the ground, as illustrated in figure 3 by the fine dotted lines connecting the horizontal line to the ground surface below. If the wire be viewed on end (fig. 4), we must represent these stress lines 246 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. as extending out radially from the wire and bending over to meet a considerable portion of the ground surface below. As this arrange- ment is constituted, there is no energy transfer and the condition is static only. If now the far end of the line is earthed, as through an instrument or device which uses energy, as in figure 5, at the moment of such connection there would be a lowering of the intensity of the stress toward the receiving instrument and the line would be dis- charged were it not for the maintaining action of the battery, which still keeps up the difference of potential between line and ground. If the line is without resistance, this potential will have the same value all along the line, especially if the line is of uniform section and of uniform distance from the ground. The moment, however, the in- strument at “I” takes energy from the line a current is found in the wire and a return in earth, and there is, so to speak, a flow of energy in the space between the FiQ. 7. wire and earth and in the ether —_— surrounding the wire, in the direc- ‘N ie 1 i Pa tion of the arrow—that is, from the generating end to the receiv- ing end. Surrounding the wire at this time there will be a magnetic field, which may be represented by whorls or lines of magnetism, away from the wire in all direc- tions; and a similar magnetic effect, of course, is also produced by the return current in the earth. But on account of the conditions of conduction in earth being very devious and irregu- lar, it would be difficult to map the magnetism generated. The sys- tem of magnetic whorls so developed on the flow of the current in the system reaches, for any definite current, a definite density after a short interval. In other words, the density of the magnetic field between the wire and the earth increases only up to a certain point. If the current, however, be doubled in any way, that field is doubled in density or there are twice as many lines packed in the space around the wire. If now we took instead of an earth-connected circuit one in which there are two wires extending from the generating battery or generator, the conditions will be the same except that the stress lines will now radiate from each wire and connect the wires by lines directly between them and by other curved lines outside. Such lines, or otherwise conceived “ tubes of force,” represent the static field or Mae so called, wrapped around the wire like so many hoops of all sizes (fig. 6) expanding in size g. 0), exp g = WIRELESS TRANSMISSION OF ENERGY—THOMSON. 24.7 the density and directions of electrostatic stresses in the electrostatic field where one wire will be positive while the other is negative. If, as before, the ends of the wire are free or open-circuited, no energy is transmitted, and the mere static stress exists. If, however, the wires are connected through an instrument receiving energy or utiliz- ing the energy, then the magnetic system is developed, surrounding each wire and passing between the wires, and on the establishment of any given current these lines accumulate at a rapid rate until, in a small fraction of a second usually, a limit is reached. The magnetic field may then be said to be fully developed. Outside of the pair of wires the magnetic disturbance extends to very great distances, but is necessarily weak far away. The magnetic whorls in this case do not center themselves in circular paths around the wires and at equal distances therefrom, but between the wires they are more condensed or pushed toward the wires themselves—crowded, so to speak—while outside of the wires they expand (figs. 8 and 9). It must be remem- bered that these lines of force are merely symbols for what may be likened to a magnetic atmosphere. They indicate the density and direction of certain actions in the ether, called magnetic. It will be important to note, both in wire and wireless transmis- — 6 — sion, that the energy is trans- ferred in the surrounding me- dium. The wire in ordinary wire transmission is, in fact, a sort of guiding center or core around which this ether disturbance carrying the energy exists. The wire may be bent or coiled, expanded or con- tracted without altering the essential nature of the process. So far, then, ordinary wire transmission is really a case of wireless transmis- sion, with the wire for a guiding core for the energy (fig. 10). Tt would take us too far to attempt to explain or theorize on the modern view of the passage of electrons in the wire forming the current, and the field they carry with and about them in giving rise to the stresses in the ether surrounding them. Suffice it to say that a moving electron must not only be accompanied or surrounded by the static stress field which it produces in the ether but also by a magnetic effect representing the energy of motion possessed by it. When a current which has been started in a circuit reaches a definite value it may be said to have reached a steady state. It would then 248 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. be a continuous current of constant value. Energy can be steadily extracted from such a system only by introducing some apparatus connected with the wire which is the guiding core for this energy. Let us now consider the case of current of a different character, a fluctuating—or better, an alternating current. Let us substitute for the battery an alternating current generator, and assume a single wire with an earth or wire return, as in figures 8 and 5. Here the wire merely becomes positive and negative alternately, for the circuit is incomplete or unconnected as a circuit, and the stress lines from wire to earth or to other wires reverse periodically their direction plus to minus and minus to plus. This is true, of course, whether the earth be replaced by a second wire or whether three or more wires be involved, as in a three-phase alternating current circuit. By connecting any two of the wires through an energy-receiving ap- paratus R. (fig. 11), the same ae- Fig. I. tion that takes place with the continuous current may be repro- duced except that the energy now rg comes in waves and is not a con- tinuous flow. In ordinary cases there are 60 complete waves or complete changes from plus to minus and back to plus in each second, and the system is then called one of 60-cycle frequency. A further important difference is to be noted between the alternat- ing-current condition and _ the continuous. The action in the ether around and between the Wires is now in the form of waves, both magnetic and electrostatic. Between wires there is an increase of electrostatic stress to a maxi- mum, a diminution to zero, a reversal, etc. The magnetic field also rises, falls, reverses, and so on synchronously. The condition is no longer static, the medium around the wires is in a dynamic state and it is now possible to abstract energy steadily from it without actually diverting current from the line. We can, in fact, by such a system produce in neighboring conductors similar disturb- ances or currents, and along with these disturbances we may deliver energy. The alternating-current transformer is then merely a device for bringing two or more circuits together as near as possible and en- hancing the magnetic values which would normally exist around such circuits by the addition of an iron atmosphere, the iron core, so that the greatest possible transfer of energy from one (the pri- WIRELESS TRANSMISSION OF ENERGY—-THOMSON. 249 mary circuit) to the other (the secondary circuit) may be accom- plished. But in the wire itself, which leads from an alternating- current source, since there is an action called a current which changes, pulsates, or alternates, we have also around the wire core waves in the ether which, in fact, spread to very great distances; some small portion of the energy of each impulse not returning to the system, but passing outward into space as radiated energy. This radiation may be a very small amount per cycle, especially where the outgoing and return wires are near together and parallel, and with low frequencies, such as 60 cycles, on account of the low number of waves per second and the low speed or rate of change in the fields surrounding the wire, the amount of energy carried off by free radiation into space is indeed negligible. But if we raise the frequency we raise the amount of energy which can be radiated pro- portionately to the number of waves per second, and we also make the rate of change higher and the wave slopes steeper, so that as the frequency rises the radiation factor becomes more and more important in dissipating the energy of the system. It will be noticed, however, that such energy is not directed energy. It is diffused through space around the electric system at work and passes off to illimitable distances. Since these impulses in the wire, the electrical waves sent along the wire (with the wire as a guiding core), can at the maximum move with the speed of hght—186,000 miles per sec- ond—it follows that if the line is sufficiently long or the transmis- sion sufficiently extended or the path of radiation sufficiently distant the wave stresses or fields or currents can exist at different parts of the system in phases either much displaced or entirely opposite. This may be rendered clear by stating that while one portion of a very long line might be positive to earth another portion half a wave length distant from the first along the same line would be negative to earth (fig. 12). In other words, there may exist upon the system at the same instant a succession of waves in opposite phase. Just as in vibrating strings in musical instruments or vibrat- ing columns of air in organ pipes there are stationary waves, nodes, and internodes, so in electrical systems in vibration there can be nodes and internodes if the conditions are selected for obtaining that effect. Here the dotted vertical line indicates the nodes of the waves. We may thus have so-called stationary electric waves (Gipy12'). We find that on raising the frequency of an alternating-current system from, say, 60 cycles, the ordinary frequency, to 600 cycles, an effect which at first was hardly detectable now becomes important. It is the so-called “skin effect” whereby the current in a wire cir- euit tends to concentrate itself on the outer skin of the conducting wire, neglecting the inner copper, so that the inner core of the wire 250 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. might be left out. Consider the frequency still further raised, say, to 6,000 cycles, this “skin effect” of the conductor still further in- creases until the copper in the interior of a circular wire of a con- siderable size is now quite useless, and to get the advantage of such copper we must, as it were, take it out or spread it in a number of parallel wires spaced apart, or make the metal of the conductor in the form of a long sheet or in the shape of a thin tube or a cage of wires (fig. 13). This, in electrical terms, improves the con- ductivity and reduces the opposition due to self-induction; the in- ductance counter E M F. Let now the frequency be still further increased to tens of thousands or hundreds of thousands of cycles per second; then our conductor must necessarily become a still thinner or a still more extended sheet. At the same time, if there are considerable differences of potential between the conductors Fig.13. thus arranged, the ra- ° o 8 diation factor may at : i 7 last become very im- Q : C) ‘3 Ke portant, so that if the ; «ae parts of the circuit are Fig. 14. far apart, free radia- tion into space may dispose of a large frac- tion of the energy sent out. In the Hertzian oscillator, deducting that lost in the spark gap, practically the whole of the remain- ing energy supplied is radiated into space. The wave frequency may be very many millions per second, and the waves produced are in the nature of coarse light and heat waves. Figure 14 exemplifies diagrammatically the fact that with very high frequency waves a conductor carrying such waves will have surround- ing it, if the space is unrestricted, magnetic systems of lines reversed in direction with nodes between, the distance apart of these waves or nodes being determined by the frequency in relation to the velocity of light, each complete wave outside the wire occupying a length equal to the velocity of light, 186,000 miles per second, divided by the wave length or frequency. Figures 15 and 16 represent forms of Hertzian oscillator, consist- ing of plates or spheres a } of metal, separated by a small spark gap and charged in any suitable way, plus and minus with respect to each other, and allowed to discharge across the gap. The charges are then interchanged between a@ and 6 at a very high rate, WIRELESS TRANSMISSION OF ENERGY—THOMSON. 251 though the waves decay rapidly, and the system vibrates only - for a short time or until the energy of the charge is dissipated in ether waves of exceeding high pitch into the surrounding me- dium. Were there no energy lost in the gap itself for forming the spark, and if the metal were a perfect conductor, the full amount of energy represented by any initial charge would be dissipated in the ether in these ether waves. Marconi, however, in his develop- ment of wireless telegraphy did not use the complete Hertzian oscil- lator. In setting up his transmitting antenna he took substantially half an oscillator, the other half being, so to speak, a phantom—the reflected image of the first half, as it were, in the surface of the earth, generally the sea surface. It would be represented by taking an extended copper sheet or surface coated with a fairly good con- ductor to represent the earth’s surface and mounting above it, but insulated from it, a metal body, such as a vertical rod, which could be charged and which could discharge to the sheet through a small air gap. In this ar- rangement not only would waves be sent out into the surround- ing ether space, but there would be cur- FiQ. 2A. rent traversing the sheet as waves of cur- ~~ i= Bhi rent around the spot “&Ss\\\ if Ge ma = Z where the discharge i [1 ges Se of the insulated body Wi took place. In fact, I + + rials Hy Me think it would be pos- sible to represent experimentally a Seats wireless system with a diminutive antenna to represent the transmitting station, and ex- tended copper sheet to represent the earth’s surface, and with investi- gating or receiving antenne set up here and there or moved from point to point on the extended surface. Here, although the disturbance and the energy conveyance is in the ether around the antenna (or the part representing the half of the Hertzian oscillator), the energy is guided in its direction by the current in the sheet representing the surface of the sea, just as in the wire transmission the energy is guided by the wire as a core. On account of the enormous extent of the earth’s sea surface, there is no need of a return circuit. The energy sent out moves in all directions, guided by the conducting water surface or land surface, as the case may be. There will necessarily be a rapid attenuation 252 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. of the energy as it leaves the sending or transmitting antenna and spreads out to fill a wider and wider space around it. The higher the sending antenna the greater the distance which can be reached before the attenuation is too great for imparting signals. Let us consider for a moment by the aid of a figure the actions which must occur in wireless transmission on the sending out of energy from the transmitting antenna. Referring to figure 17, we will represent by e—e the surface of the earth as if it were flat, and for moderate distances this will be substantially the case. We will erect on that surface a tall mast A of conducting wire or wires which, at the top, shall have an extension to increase its capacity. This might be a large ball of sheet metal. Usually, for construction to be practicable, it is a set of wires—a sort of cage or a skeleton body. Now, by any system, inductively, conductively, or otherwise, or by what is known as close or loose inductive coupling or what not (figs. 18, 19, 20) we cause elec- Fig 18. Fig. 19. Fig. 20. tric disturbances, such that at one instant the top of the antenna be- comes positive and at the next instant nega- tive, many thousands— even hundreds of thou- sands—of times per second. Inotherwords, we impress a high-fre- quency wave upon this vertical mast. We will try to present an in- stantaneous picture or form an instantaneous image of bans: the condition is at the beginning of the process. Let us suppose that the charge is positive at the top, and necessarily the surface below and surrounding the mast will be negative. Elec- trostatic lines will extend from the mast, and particularly from the expansion at the top down to the earth’s surface in all directions around the antenna, as in the figure. The medium around the antenna will be stressed electrostatically. This would be all, pro- vided the charges were stationary, but the system we are considering is dynamic. The plus charge is replaced by a minus charge at the top, and a current of a high frequency runs up and down the antenna, but so also does this current extend into the sea radially from the foot of the antenna, replacing the negatively charged area by a posi- tively charged zone, as it were, while the top of the antenna is now negative where it was formerly positive. (Fig. 21 A (p. 251), one side only shown, and fig. 21 B, in plan.) WIRELESS TRANSMISSION OF ENERGY——-THOMSON. ONS As this action goes on, however, the zone of charged surface widens, and ether waves are, so to speak, detached from the antenna, and electrostatic lines join now through the air or ether above the successive zones which surround the antenna as great circles or flat rings of the sea surface. A plus area is followed by a minus, a minus by a plus, etc., and to indicate the effect in the space above, we draw lines which follow these areas, extending up into the ether above the surface, but moving away from the antenna with the velocity of light. The moving charges in the sea surface represent radial currents which are in opposite phase at different portions of the sea surface, and spreading at 186,000 miles per second, and these currents neces- sarily generate magnetism or lines of magnetic force in the medium directly above them. These lines extend around in zones with dimin- ishing intensity upward from the sea surface as the distance from the surface increases. Even within the water itself a similar action, but more restricted, takes place. The charges in the water are connected by electrostatic stress lines, and the compensating magnetic field fol- lows the current, but this “ under water” effect does not concern us, as what we work with is the energy conveyed in the space above the sea, the other not being so easily recoverable. The system as thus far consti- tuted is merely an arrangement for ek delivering energy in high-frequency eee waves to the widespread medium around the antenna. ‘There is no selective action whereby it is focused anywhere—it is as a “voice crying in the wilderness.” It can be picked up or recognized in any direction by anyone who is within range. If, now, we are to receive signals such as are made by interrupting or disturbing at intervals this system of radiation of energy, as in ordinary telegraphy, we must set up somewhere a receiving apparatus which will enable us to pick up whatever small fraction of the energy reaches it and, if possible, a sufficient fraction of such energy for the recognition of the signals. If the signal can be recognized—no matter how small the fraction of the energy sent out is which we collect at the receiving station—the system succeeds. There is no question of efficient transmission, as there is in the ordi- nary power-transmission systems. The latter are for the transmis- sion of energy with as little loss as possible, the former for the trans- mission of signals only. 254 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. In the antenna transmission just considered it is assumed that the surface of the earth is, generally speaking, a good electric conductor. The surface of the sea is sufficiently good. Dry land surface, how- ever, is not a good conducting sheet, and even though moist it is generally so irregularly conducting that obliteration of the waves and loss or absorption of the energy must necessarily occur. Obsta- cles, such as dry rock ranges, may absolutely prevent the waves from passing over them. It must be borne in mind that these waves have no inertia, as such, and that the energy must be guided to its desti- nation by a conducting sheet. This calls to mind the efforts that were made to connect Lynn and Schenectady by a wireless system, but without success. Occasionally signals were received, but in gen- eral they were too indistinct to be recognized. It is more than probable that the dry rock ranges of the Berkshires in western Massachusetts were sufficient of an obstacle to prevent the energy of the waves getting across them. It is also to be questioned whether there may not be another action which interferes with and disturbs the integrity of the waves. It is conceivable that waves may follow a water surface, even around a eape, and that a portion of the energy may take a short cut across the land of the cape. If this be so, the longer course would be around the cape, the shorter course across the land. The wave lengths would remain the same, and an out-of-phase relation or interference phenomenon would take place to a greater or less extent. It is manifestly necessary that the energy, by whatever course it fol-_ lows, shall reach the receiving apparatus in phase. Let us now consider for a moment the conditions at great dis- tances over theearth’s surface. At moderate distances from the trans- mitting antenna the surface may be considered as flat. _The conducting sheet guiding the energy is flat or plane, but at great distances the curvature of the earth’s surface becomes an important factor. Fora time there was a great deal of discussion as to the reason why the energy in the wireless transmission seemed actually to follow the curvature of the earth, instead of going straight away, as in the case of Hertzian or heat and light waves. If the waves had been generated by a large Hertzian oscillator, it would not be possible for them to so follow the earth’s curvature, but inasmuch as they are in wireless work produced and, as it were, positioned upon a conducting sheet (the sea surface), then it follows that the energy must be guided by that conducting sheet or surface, regardless of its extent or its curvature. IT have never been able to understand why so much discussion has been needed to clear up this point. Wireless waves have no inertia— they follow the course of the charges which produce the stress and of the magnetic field, due to these charges in motion. These charges in motion are the currents in the conducting sheet, which may or i WIRELESS TRANSMISSION OF ENERGY—-THOMSON. 255 may not be curved. In the curved surface of the ocean the zones of charge continually expanding, plus and minus, respectively, are still connected by the electrostatic lines above them, and the moving charges still generate the same magnetic field as they traverse radi- ally or outwardly in the curved instead of the plane sheet (fig. 22), and this curved conductor still guides the energy, just as the wire does in ordinary transmission. It would seem, if this is the correct view, that at a distance comparable with that of a quadrant of the earth’s circumference the form of the wave would be such as to cause the stress lines to lean backward with respect to the surface, tending to keep their original relation to the transmitting antenna as they were detached therefrom (fig. 22, at L). This assumes that the velocity of transmission is the same as that of the speed of light, both for the currents in the sea and for the stresses above it. Marconi’s success as a wireless pioneer depended largely upon the choice of a sufficiently sensitive receiver. Two elements are necessary in the receiver. First, a conducting structure which gathers up the energy from the medium, the ether, above the earth’s surface. The other element is a sufficiently delicate means for detecting the slightest changes of electrical condition, not only actuated by what little energy is received, but so modifying it that it can operate a signal which can be seen or heard. Usually the receiving antenna is a ver- tical conducting mast or cage, like the sending antenna. In fact, the functions of sending and receiving are interchangeably used on the same structure; the same antenna may be at one time used for transmitting and at another time for receiving. The receiving antenna (fig. 22) serves to relieve the electrostatic stress in its vicinity, much as a lightning rod may act to relieve cloud to earth stresses. If its direction could be made to follow or be parallel to the actual course of the transmitted lines in the space near it, it would be most effective, and if, further, it could extend sidewise over a considerable extent of the wave front, it would gather up more energy. These conditions, however, can at best be only ap- proximately met. If the receiving antenna were of such a character as to have no oscillation rate of its own (a damped circuit) it would recelve energy in a small amount from the transmitting antenna independent of the frequency, but as this would in most cases be far from sufficient, it is desirable to accumulate energy in the receiver from a train of waves at a definite rate. To do this the principle of syntony or tuning is brought in. Everyone is familiar with the two tuning forks, where one is sounded and the other is placed at a dis- tance away. If the two forks are not in harmony, no effect of the one fork on the other follows, but if they are accurately tuned in unison, the sound of one fork at a considerable distance from the other starts the second in vibration and produces an audible sound 256 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. from it. The second fork is, in fact, a structure particularly well adapted to gather up the energy of the sound waves which reach it, receiving from each wave a small portion of energy and accumulating such energy until the fork itself is brought into palpable vibration. By applying this principle in wireless telegraphy—that is, by causing the rate of vibration or frequency of the electrical waves to be the same in the transmission and in the receiving antenne systems, con- structing both to possess a normal rate as if they were to be electrical tuning forks of the same pitch—the amplitude of the received im- pulses is so greatly increased that signal strength is reached where otherwise failure would have resulted. The one thing which has characterized the more recent advances in wireless telegraphy has been the accuracy of tuning and the removal of disturbing influences which would interfere with the tuning. Formerly the transmitting circuit was excited by means which tended to disturb the actual normal rate. If excited inductively, the inducing or primary circuit had a rate of its own, which was apt to interfere with — that of the vibrating .antenna system. However, what is known as loose coup- ling (fig. 20), in- stead of close coup- ling (fig. 19), to the primary or exciting circuit causes such confusion of rates to be nearly negligible if, particularly in the exciting circuit, the current is well damped, as it is termed, or con- fined to a single brief impulse as far as possible. In such case the antenna circuit, in transmitting, acts as if it were a bell struck with a sudden quick blow, and it vibrates at its own rate without dis- turbance or interference. At the receiving end (and there may be, of course, many receivers in the space around the transmitting antenna), the “listening-in ” process consists in adjusting the rate of vibration of the receiving circuit by variable condensers or induc- tances, so that the maximum loudness of the received signals is at- tained. The two systems, transmitting and receiving, are then in tune. Accuracy of tuning is evidently very important if stations are to be simultaneously transmitting when near together, as only in that way can one station send out energy without interfering with the other; the particular receiver for which the signals are intended be- ing tuned for the particular antenna sending these signals. In spite THOMSON. 257 WIRELESS TRANSMISSION OF ENERGY of the accuracy of tuning, however, high-power stations may, in fact, cause high frequency waves of high potential in all surrounding wire or metal structures if near enough. Burn outs, or even fires, may occur from this cause. Hence it is desirable that high-power sending stations should be well removed from centers of population where there are electric circuits and electrical apparatus likely to be inter- fered with or injured. It may be here pointed out that de limit of potential which is available in wireless transmission is the same as that of long distance transmission by wire and for the same cause. Naturally, if the po- tential on the sending antenna can be raised, the amount of energy which can be put into the wave impulses will be increased, but there comes a time when an increase of potential on the wires of the antenna gives rise to a corona loss—much as the increase of potential in wire transmission produces a corona loss. The conductors of the system, in such a case, are surrounded by a blue discharge which is even visible at night and which frequently can be heard. When this con- dition is reached every further increase of potential simply increases the corona loss without adding correspondingly to the energy trans- mission. Just as in wire transmission it can be avoided by increas- ing the diameter of the conductors, so in wireless work it could be avoided by constructing the antenna system of hollow tubes with smooth exteriors, and the imagination may be permitted to depict a sending tower of polished metal surmounted by a sphere of similar material and worked at millions of volts. No limit can be set to the amount of energy which might thus be radiated, and no limit as yet can be set to the distance around the earth to which signals might be sent by such means. One curious fact which has been developed in the work of wireless signaling is that daylight, especially sunlight, is very detrimental to transmission as compared with the night. That is to say, if the wire- less waves are to traverse the sea surface in sunshine, the chance of receiving them in sufficient force to produce signals at great distances is far less than when they are sent at night. It is probable that this difference is not due to any single cause—it may be the effect of a combination of causes. It is a notable fact, too, that this difference between the effectiveness of daylight transmission and night trans- mission is accentuated at the higher frequencies. Though the cause is still somewhat obscure, we may venture a suggestion or hypothesis which may have a bearing on the case. Referring to figure 23, we have tried to show the condition. The electrostatic field at the water surface at the same instant is as in figure 21 produced in zones around the antenna 4, spreading with upproximately the speed of light. It is well known that under the 44863°—sm 19183——17 258 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. action of the violet and ultra-violet rays of light any surface, having a negative charge will leak its charge and ionize the air near it. This may occur in sunlight over such areas as are marked minus in ithe figures, and the several minus signs would mark or indicate air ionized and negatively electrified over the negatively charged zones. No action would be expected over the positive areas or zones. But ihe zones are not stationary; they are widening very rapidly, so that a positive zone or zones takes the place of negative so far as any location is concerned. This may be expressed by saying that the water surface which at one instant was negative and gave out negative ions under the influence of light would, in an exceedingly emall fraction of a second and before those ions could get away from electric contact with such surface, become positive and the free ions would now return and neutralize a portion of the positive charge. Thus the negative zones or wave elements would lose part of their charge to ionize air, Fig. 23. and the positive waves would be weakened by such negative leak neutralizing them in part. This action, however feeble at each wave, would be con- tinuous over hun- Fig. 24. - dreds if not thou- sands of miles, and continuously damp out the widening system of waves. The effect would be less marked with low frequency waves, as there would be a proportionately less number of oppor- tunities for this neutralization per second. Besides, with the lower frequency there is more time for the separation of the negative ions to such distance from the water surface that they do not combine with the positive charges; being, as it were, better insulated from them or diffused in the air stratum. In figure 24 an attempt is made to picture this action of attenua- {ion in the presence of light. The negative charges in the air layer, as in figure 23, have no positive charges under them, the encircling lines about the ++ and — signs indicating combination and neutraliza- tion. When the wireless waves reach the receiving antenna, owing to at- ienuation from spreading or loss as above, they are very feeble. The y if Dy | WIRELESS TRANSMISSION OF ENERGY—-THOMSON. 259 daylight effect, as pointed out by Fessenden, is much less with the lower frequencies, such as 100,000 per second as compared with 600,000 or 800,000 waves. Consequently there is not the same great difference in strength of signals between night and day work with such lower frequencies. Moreover, frequencies of 100,000 or even 200,000 are capable of being generated directly by high-speed high- frequency dynamos with the added advantage that the waves sent out are maintained at their full amplitude and are not, as with waves produced by spark discharges, subject to damping or decay from maximum to zero after a few oscillations. Whatever the nature of the waves sent out, there is in all cases the need of an exceedingly sensitive apparatus for converting the slight electric effects upon the receiving antenna into signals. The origi- nal apparatus of Marconi included the Branly coherer, used by Lodge in Hertzian wave transmission as a detector. It is indicated in figure 26 at A’, with its battery and sounder magnet J/. The re- ceiving antenna discharge in passing to earth broke down the in- sulation of the filings of the coherer, so that the local battery cur- rent could pass in the circuit, including a mag- Fig. 25. Fig 26. Fig. 27 net M/ and so record the | signal. The liquid bar- retter of Fessenden, the | various forms of recti- fying crystal detectors and magnetic detectors, cs have been extensively used. Our time does not permit a detailed de- scription. Figure 25 in- dicates at C a crystal detector rectifying the impulses from antenna A so as to work a high-resistance telephone receiver 7’, to which the operator listens. [igure 27 shows the same apparatus, but connected inductively to the antenna circuit by a transformer. reaching the telephone 7’ was such as to produce a low note, the signals were easily drowned by extraneous noises or induced effects. He found that the human ear reached a maximum of sensitiveness at about 900 waves of sound per second, so that the signals were heard distinctly when otherwise they would have been missed. This is the meaning of the substitution of dynamos of about 500 eycles for exciting the wireless antenna in place of the ordinary machines of lower frequency. The problem of wireless telephony: has attracted attention for a number of years past. I well remember witnessing some of the 260 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. earlier work of Fessenden in this fascinating field, in which he was pioneer. The wireless telephone speech was free from all disturbing noises and interferences so common on ordinary telephone lines. Briefly, such telephony depends on the ability to control the voice waves and vary in accordance therewith the energy given out by the transmitting antenna and to do this with a fairly large output of energy. By employing a method I described about 1892, it is possible to generate a continuous wave train by shunting a direct current are with a capacity (condenser) in series with an inductance, the fre- quency rate depending on the electrical constants of these parts of the apparatus. This system, which was the subject of the United States patent taken out by me in the early nineties, has been vari- ously called the Duddell singing arc, or later the Poulsen arc. Poul- sen employed it with modifications in his system of wireless tel- ephony. Long before this work of Poulsen, Fessenden had used a high-frequency dynamo for securing the continuous train needed. A suitable microphone transmitter was made to so alter the rela- tions of the waves in transmitting and receiving antenne, that voice waves could be received in an ordinary telephone connected with the recelving antenna system. Much progress has been made in this department of wireless work, and such telephony between Europe and America may yet become practicable. Methods are being worked out whereby it may be possible to mold outputs of many kilowatts of energy so as to have them vary with the voice waves, and when this is done many prob- lems, the solution of which now seems remote, may become solved and the results prove of great practical value. It was not, however, my intention to devote time to these later researches, but to endeavor to present to the mind’s eye a view of the nature of wireléss trans- mission which should show the similarities to ordinary transmission by wire and also the differences. Furthermore, I hope I have shown it to be evident that future transmission of energy at high efficiencies will still demand the wire core for guiding that energy to its destination. OIL FILMS ON WATER AND ON MERCURY:.! By HENRI DEVAUX, Professor on the Faculty of Sciences. at Bordeaux.’ [With 7 plates. ] Certain phenomena of daily observation are of great interest to the physicist. Especially so is the expansion of oil over the sur- face of water or of mercury. I have studied this matter for a long while and from all my observations several unexpected facts stand out. Films of oil tell us with the greatest nicety of the discontinuity of matter, and the dimensions of molecules. They also give us val- uable information as to the field of molecular action. For our observations we will find that there is no need of complicated ap- paratus; basins, paper, threads of glass, a pipette, a sieve with some tale powder, and finally some oil and benzole suffice for the greater part of the experiments. As to measuring instruments, a double decimeter will do, although its divisions be a million times greater than the diameter of the molecules. Though it seems like measuring microbes with a surveyor’s chain, we will see that the measures not only can be made but made with great precision, because of a very remarkable peculiarity of films of the thickness of one molecule. We will yet further see that the smallest variation in homogeneity engenders considerable differences in the surface tensions, causing the molecules to become exactly equidistant. 1 Translated by permission from Revue générale des Sciences pures et appliquées, Paris, 24th year, No. 4, Feb. 28, 1913. 2This article gives a summary of all my researches upon oil films published since 1903; it includes also several new results relating especially to films on mercury and the interpretation of certain observed facts with them. The greater part of the figures have not before been published. The following is a bibliography of my earlier researches : Recherches sur les lames trés minces, liquides ou solides (Proc.-verb. Soc. Se. Phys. de Bordeaux, Noy., 1903); Membranes de coagulation par simple contact de l’albumine avec l’eau (1. c., Jan., 1904) ; Comparaison de l’épaisseur critique des lames trés minces avec le diamétre théorique de la molécule (1. c., Apr., 1904) ; De l’épaisseur critique des Solides et des liquides réduits en lames trés minces (Bull. des séances de la Soc. france. de Phys., p. 24, 1904) ; Recherches sur les lames d’huile étendues sur l’eau (J. de Phys., Sept., 1912, p. 699); Sur un procédé de fixation des figures d’évolution de Vhuile sur Yeau et sur le mercure (Journ. de Phys., Oct., 1912). Several physicists have honored me by taking an interest for several years in my researches into molecular physics which has greatly encouraged me in carrying them out. I especially wish to mention M. Ch. Ed. Guillaume, president of the Société de Physique and M. M. Brillouin, professor at the Collége de France. 261 262 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. I. THE LIMIT OF THE HXPANSION OF OIL OVER WATER. We will first look at an experiment of elementary simplicity yet fundamental. Let us pour some water into a photographic tray and then remove all the impurities from the surface by placing upon it just a sheet of thin paper. Then I scatter on the surface a little tale powder and place upon it a trace of oil by means of a very fine capillary tube. The oil spreads out rapidly from the tale in a circle, since the normal surface tension of the water is considerably lowered. But if there is very little oil, such as the capillary will take up by just touching the stopple of the bottle, the expansion stops suddenly, so that we have a circle of oil surrounded by free water. Yet is the water really free? Perhaps there are traces of impuri- ties which stop the extension of the oil. This is not the case. Let us touch with a trace of oil another point distant from the first one touched; a new circle forms and extends outward from the tale, but the first one is in no way affected. No equilibrating impurity exists outside of the first circle, otherwise its surface would have been deformed and diminished. There is therefore a real limit to the extension of oil upon water. And when that limit is reached the surface tension is both that of pure water and of oiled water. Let us throw upon this water some grains of camphor dust. At once we see the grains in lively motion, but everywhere with appar- ently the same speed whether within or without the oiled region. We may proceed differently. First spread over the water a sheet of oil, powder it, and then try to enlarge a little portion of the oil film by means of a strip of paper placed across it and over the edge of this dish. At once the whole surface is covered, since the layer of oil was somewhat thick. But there always comes a time when the extension stops; the oiled region marked by the tale remains behind, although there is a surface of water free from both tale and oil. The limit is extremely clean cut and we have side by side two sur- faces with the same surface tension—one of free water, the other of oiled water at its maximum extension.’ Tf at this moment a little camphor dust is scattered on the surface, the grains will be seen in active motion. In getting out of the way of the tale they act like little tadpoles. If the surface is reduced to one-half all motion stops suddenly and the tale gathers around each particle of camphor. We may put upon the water a little tin boat 1In 1891, Mlle. Pockel pointed out to Lord Rayleigh in a letter published in Nature (English) on the 12th of March, p. 457, some experiments relating to these facts. In enlarging progressively a surface of oil upon water or of water soiled with any other impurity, the tension of that surface varies continuously (abnormal condition) ; it in- creases slowly at first, then very rapidly, and reaches a maximum. Any further extension from the maximum point leaves the tension invariable (normal condition). If Mlle. Pockel had scattered an inert powder upon that surface to render it visible, she would have realized that, as soon as the maximum is reached, the oil would extend no further. a = OIL FILMS ON WATER AND MERCURY—DEVAUX. 2638 such as I devised in 1888,1 and which is shown full size in figure 1. A little fragment of camphor is stuck with wax in a notch in its rear. A little mast bearing a streamer is fixed in the middle. This little boat, placed upon the water, moves rapidly and continuously so as to be seen from all parts of a room (pl. 1). T used this device the 19th of April, 1912, in Paris before the So- ciété de Physique. Placed at first upon water with a film of oil at its maximum extension it traveled just as on pure water, leaving in its rear a large wake; the tale was thrown out with a marked vibra- tion whenever it came in contact with the camphor, just as if the camphor corresponded to the propeller of the boat. I diminished the surface. At once the wake became smaller. The boat slowed up. I made the surface yet smaller. The boat stopped. I increased the surface, the boat again moved. We may thus, by the simple movement of a capillary barrier (a strip of paper), show to a whole audience the effect of sudden and considerable changes which the surface ten- sion of water undergoes when covered with a film of oil of the critical thickness. It is a very simple experi- ment and very effective. ‘Therefore it is particularly interesting to know what thickness the film of oi] must have at this remarkable phase. II. THE THICKNESS AT MAXIMUM EXTENSION. ci (1) Ef eperimental measures.—Lord Rayleigh, in his — yy¢1-camphor admirable experiments of 1890, tried to find what is the —-» oat (natural ate E : size); c, grain of minimum quantity of oil necessary to stop the move- crete the ment of the camphor? and found an extremely small _ stern: m, mast value, a thickness of about 1.6 yy. In 1891 he published ga ih the letter of Mlle. Pockel, which we have just mentioned, and in the following year * showed the stopping of the movements of the cam- phor by a greasy body is due, as the law discovered by Mlle. Pockel led him to see, to a sudden fall in the surface tension of water when the grease layer has the right thickness. In 1899 he published a curve showing the relation between the surface tension and the quan- tity of oil* and showed that the proportion of oil when the surface 1 See La Nature, April, 1888. 2 Proceedings of the Royal Society, 47, Mar. 27, 1890. A French translation of the article will be found in Conférences et allocutions de Sir William Thomson (Lord Ray- leigh), translated by Lugol (18938), p. 48. 3 Philosophical Magazine, 33, p. 366, 1892. 4Philosophical Magazine, 47 and 48, 1899. In obtaining this remarkable curve, Lord Rayleigh appears to have supposed implicitly that the oil on the water always forms a continuous and homogeneous film, even when its surface is much diminished; for ex- ample when he gets the quotient of the weight of oil by the surface occupied. This is proper only when the diminishing of the surface is small, say in the ratio of 1 to 1.3. Beyond this limit this process is in error, for the surface begins to assume a globular form, finally becoming a veritable mass of foam. We will speak of this later on, 264 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. tension of the water begins to fall is about one-half that at which the camphor movements stopped. The thickness is therefore 1.6/2 or 0.8 pu. But Lord Rayleigh gives it as simply 1 py. We may obtain a yet greater precision by a method using drops of a standard solution of oil in a volatile solvent. I prepare a standard solution of oil in pure benzole. I use a solution containing exactly 1 cu. cm. of pure oleine (trioleate of glycerin) per 1,000 cu. em. of benzole and a pipette giving 50 drops of this solution per cubie centimeter. Thus a drop contains sp¢p, of a cubic centimeter of oil, and I place two of these drops upon the water. As soon as they touch the water, the drops spread over the whole surface; the evapora- tion of the benzole is almost instantaneous and leaves a residue of oleine equal to sp255 or 400X10-7 cu. cm. Earlier measures showed me that this quantity of oil could not cover all the surface of the tray p P Fig. 2. Fig. 3. Figs. 2, 3.—Arrangement for measuring the limiting thickness of a film of oil; H, film of oil; H, free water; 7'7’, barrier of powdered tale; BB”, band of paper. (625 sq. cm.). I blow upon it to gather the invisible film of oil at the farther end of the tray and then scatter upon the nearer end a light veil of powder with the sieve. The tale thus falls upon the free surface of water / (fig. 2); it scatters, carried by my blowing, but! you see it stops abruptly along the barrier 77’, which though invisible was sharp, and marks the edge of the oil film H. The stoppage is of striking sharpness. I now apply to the portion of water uncovered with oil a band of paper BB’ (fig. 3), m order to have a straight capillary border. I now make this barrier approach gently the border of tale which straightens, as is indicated in the figure.’ If the barrier is moved a little farther, the tale grains just at the limit of the oil, and more or less distant from each other because they are slightly oily, we see 1TIt is yet better to collect the tale scattered upon the free surface by the band of paper itself. : Smithsonian Report, 1913.—Devaux. PLATE 1. BOAT EN ROUTE IN BLACK TRAY ON WATER POWDERED WITH TALC. A large wake of camphored water free from tale is very visible atthe rear of the boat. The operator contracts or expands the free surface by changing the position of the strip of paper placed across the tray. OIL. FILMS ON WATER AND MERCURY—DEVAUX, 265 undergo an abrupt closing up between the oil and the paper. Retreat the barrier, and all at once the same grains become free, again floating freely side by side. By means of these sudden changes and by mov- ing the paper slightly back and forth, I can accurately, within a few millimeters, find the limit at which the oil is just slightly contracted, that is at the place where there is the first appearance of change in the tension. At this place I make my measure, determining once for all by my double decimeter rule the length of the film of oil. (2) Results.—We thus get the area of the mean surface covered by the film. In the experiment made the 18th of April, 1912, it was 363.71 square centimeters. Now, this was produced by two drops of the oil solution; that is, by 400X107 cubic centimeters of oil. The thickness of the film was therefore: V_ 400X107 Bit abave =1.10 pp with an approximation between 1.04 and 1.15 py. We can then state from this that the thinnest film of oil which can exist upon water is one and one-tenth millionths of a millimeter. This thickness, almost identical with that found by Lord Rayleigh, is remarkably small. A simple comparison will give us a better idea of it. Let us imagine a film of this thickness covering a globe 50 centi- meters in diameter; let us enlarge in thought this globe until it has the actual dimensions of our earth. The film enlarged in the same proportion will acquire a thickness of only 26 millimeters, while the paper which covers the globe and upon which the world map was made will increase from its original thickness of 0.1 millimeter to 24 kilometers ! (3) Comparison with molecular dimensions.—But we may make better comparisons. In the molecular theory, the thinnest film of any substance which can exist is evidently made of a single layer of molecules; for it is impossible to conceive of a film thinner than a molecule except through the deformation or destruction of the mole- cule itself. We possess to-day very numerous and exact determinations of the Avogadro constant, allowing us to calculate molecular dimensions. We have made the calculation for oil, or rather for the trioleate of glycerin. Using Perrin’s value for Avogadro’s constant, we found 1.13 pp for the molecular diameter. The theoretical value of the diameter of a molecule thus calculated is practically identical with 1.10 py, the experimentally measured thickness of an oil film at its maximum extension. The difference is only in the hundredths of a micron. 266 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. We know therefore that a film of oil at its maximum extension is formed of only a single layer of molecules... This remarkable fact is true of other films than those of oil, nor is it limited to liquid films. I have found it to be equally true for various solid substances, with this difference: it is the solid state itself which disappears at the critical thickness and not the surface tension, as with liquids.* T therefore derive this general conclusion: the characteristic mechan- ical properties corresponding to certain states of a body, the sur- face tension of a liquid or the rigidity of a solid, persist almost intact down to molecular thicknesses, disappearing abruptly the minute we go further. This fact has a general significance which we should appreciate. For the present, however, we will be content in seeing a new and direct demonstration of the discontinuity of matter and the reality of molecules; it is indeed a new method allowing us to measure the dimensions of molecules with a precision comparable with that of the best methods we have. Ill. THE EVOLUTION OF LARGE DROPS OF OIL UPON WATER. Instead of placing upon the water a very minute trace of oil, let us put there an ordinary drop of one to three hundredths of a cubic centimeter. We will now watch a series of phenomena as interesting as what we have just seen. Scarcely does the drop touch the water when it spreads out and covers the whole surface. But the film, of course, is very thick. It is hundreds of molecules thick and clearly visible, because it reflects light better than does water. Generally we see interference colors, at least at one phase of its extension. But this phase is always fugitive, especially with nondrying and fresh oils and when the surface of the water is very clean. This is the case with the present film. The evolution of a film lasts but 10 to 15 seconds; indeed the principal phases take place in the first 3 seconds. However, on water already oily, the formation is very much retarded and the film appears with a sharp circular border, as in plate 7. Soon its brilliant surface is pierced with black, circular spots looking like holes, where the water appears as if free from oil. These spots, more or less numerous according to the kind of oil, gradually grow in size, and each one is finally surrounded by a band of small droplets similar to pearls (pl. 3). The first of these spots appears near the edge of the film, where it is thinner than at the center. They grow very rapidly and soon run together. The spots over the rest of the film subsequently behave in 1QLord Rayleigh in the research cited above discussed this question, but the knowledge then of the value of Avogadro’s constant was not so accurate. 2 Devaux, |. c., 1904. y 8The process of fixation of these films is peculiar and has been described in a special communication (1. ¢., Oct., 1912). Smithsonian Report, 1913.—Devaux. PLATE 2: FILM OF OLIVE OIL AT THE BEGINNING OF ITS EVOLUTION UPON PURE WATER (LESS THAN ONE SECOND AFTER THE DEPOSITION OF THE DROP). The center is thick (rings and interference colors), the border thin (brown of the first order, 100 yu, then paler and paler white). The film is, however, already pierced with circular holes, yet small and rare at the center, large and fused together at the edge. There are fine droplets at the edge. Smithsonian Report, 1913.—Devaux PLATE 3. FILM COMPLETELY EXTENDED, AGE ABOUT TWO SECONDS. Its spread has reached the phase when first-order tints appear. A general shrinkage is taking place everywhere. The central black spots have increased in size and fused together; their borders are much broken up and are surrounded by various sized droplets. OIL FILMS ON WATER AND MERCURY—DEVAUX. 267 the same way (pl. 4), so that finally the film is changed into groups of droplets scattered over the surface of the water, which reappears as if free from oil, and uniformly dark (pl. 5). It is evident, however, that the surface of the water is yet covered between the globules by a very thin film of oil; and the persistence of this final phase shows that it remains in this discontinuous condition because the oil on the water is almost in static equilibrium. It is therefore necessary to distinguish two phases in the development of an oil film—the evolutionary phase, always fugitive, and the final static phase. IV. THE STATIC PHASE OF OIL UPON WATER. Let us consider especially this last phase, that of a very thin, con- tinuous film extended over the surface of the water and studded or not with globules or disks. We will begin by establishing an im- portant fact: the thickness of this continuous film depends upon the existence and dimensions of the globules. Because we find that when a film with minute globules exists beside one with great ones, the first always contracts at the cost of the second. Since, therefore, the tension is stronger in the former, we must conclude that the film with minute Le ae is the thinner. With regard to the thickness of thin films, we are then led to dis- tinguish four cases: the maximum and minimum thickness of films without globules; the maximum and minimum thickness of films with globules. Practically these reduce to three cases, since the maximum thickness of a film without globules is necessarily the same as the minimum thickness of one with globules. (1) MINIMUM THICKNESS OF FILM WITHOUT GLOBULES. We have already measured this thickness since it occurs in a film at its maximum extension and it is about 1.10 py. (2) MAXIMUM THICKNESS OF A FILM WITHOUT OR THE MINIMUM THICKNESS OF ONE WITH GLOBULES. (a) Principle used in measuring films of a thickness greater than that at the minimum: While the minimum thickness of oil films is easy to obtain and even to measure, because of the sudden and con- siderable change in the surface tension for small variations in thick- ness, this is not the case for thicker films; for when we pass the eritical thickness, the surface tension scarcely alters even for very great variations in the thickness of the film. It is therefore much easier to measure a film at its minimum thickness than at a greater thickness. However, since it is always possible, by enlarging the film, to pass from a thicker to a thinner film, this difficulty can be avoided. 268 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. We can then in any case choose an oil film without globules having the desired thickness, isolate a portion of the surface, 8, then enlarge this to its greatest extension, S’. It will then have its minimum thickness. The ratio S’/S will be the ratio of the two thicknesses. Since the minimum thickness is known, we obtain the other thickness by multiplying by this ratio. (6) Experimental procedure: In order to determine the greatest thickness of an oil film without globules, I proceed as follows. By means of a glass fiber, I place upon the water of my tray a drop of several tenths of a cubic millimeter. It expands into a film which contracts very quickly into a multitude of little droplets scattered over a black film. I now place a sheet of paper over the greater part of the surface and move it very slowly toward me. Immediately we see the globules over the rest of the surface grow into brilliant disks which finally break up into smaller drops. Repeating this par- tial wiping away several times, the globules one by one disappear, each momentarily becoming a disk, multicolored or of brilliant white. Finally the whole surface of the water appears*black. But there are still very small droplets which may be made evident by slight en- largements made by jerking the dish. Each one gives a flash of ight and then disappears. The final phase of the phenomenon requires acute observation, especially for some oils which produce particularly fine globules. In such cases I scatter a light veil of tale powder on the film, then extend the film slightly and at once we see the talc thrown out in little circles about each minute globule. . (c) Results: The following table shows results obtained by the process just described. It gives the ratio between the greatest and least thickness we can have with films without globules. PETAL LEI EY cea SO I cee Ok Ao OS ie 1927 1. 28 “TERY OT UE) 2 SS SS ie IR ne DU The 12 el t22 Renee O Uber ats we EE gt ip telat ke eR eye ee L18 a 1S BSL Ess VOM peewee seek uM ie oad SET Ry Seek ee Sa 1.18 WOE Ver A101 Seek ce 2 Rs Ree as a FR ROCESS RS 1.16 Sheeps-foot “oile.3 hae Lees ee eh ee 1.16 Castor Oi]! scares RE ey ee ee ils 5s) The ratio of the maximum to the minimum thickness for an oil film without globules varies a little from oil to oil, but it is always less than two. It is usually very close to unity, so that a film ex- tended over water can have a maximum thickness but little superior to its minimum thickness. We may otherwise state this. A film thicker than one molecule can not exist without nearly all the excess of oil forming into globules. (d) The formation of foam in a very shrunken oil film: The last experiment explains a very curious and interesting fact. If we re- duce an oil film from its maximum extension so as to diminish its surface to one-tenth or one-twentieth of its original area the film Smithsonian Report, 1913.—Devaux. PLATE 4. VERY ADVANCED STAGE IN THE BREAKING UP AND CONTRACTION OF AN OIL FILM BY THE FUSING OF THE BLACK FILM AND DROPLETS INTO DROPS OF VARIOUS SIZES. This film is about three seconds old. Smithsonian Report, 1913.—Devaux. PLATE 5. FINAL NEARLY @) STABLE STATE REACHED AFTER 10 TO 15 SECONDS. The oil film seems reduced to a cloud of fine droplets scattered over the water. Inreality, a very thin continuous oil film exists between the droplets. The figure of equilibrium of oil on water is therefore discontinuous. (1!) I say ‘‘nearly”’ because the drops are still undergoing small displacements; they are approaching each other and fusing into larger droplets. This fusion is often hindered by an increasing viscosity, leading to an apparent solidification of the oil in contact with the air. DEVAUX. 269 OIL FILMS ON WATER AND MERCURY loses its bright aspect, becoming leaden and as if covered with an exceedingly fine foam. Microscopic examination assures us that the oil has changed into a multitude of droplets of various sizes, 10 p, 5, 1p, and less. Working in the sunlight, I have seen the foam ap- pear before the film has been reduced to one-half its maximum extension. This is a new and direct proof of what we have just learned, that as soon as an oil film is so much reduced in surface that it is more than one molecule thick, nearly all the excess of oil forms into globules. (e) Variation of molecular distances: This extraordinary fact gives a new and interesting insight into the field of molecular action. It shows particularly that the forces which stretch out these films of liquids are due almost wholly to a single layer of molecules and that the surface layer. It is evident further that a film, if it is uniform, must be greater than one and less than two molecules in thickness. Now, everything indicates that a film is really uniform and homo- geneous, since the least variation in its thickness gives rise to con- siderable differences of tensions which tend to reestablish everywhere a perfect homogeneity, and especially the equality of molecular dis- tances. The difference between the states of least and greatest exten- sion can be dependent then only on the distances between the mole- cules; if they are compact in the first case, they can not be so in the second. At any rate, that is the interpretation given by M. Brillouin in a discussion which followed my communication.t The distance apart of the molecules in such films will be inversely as the square root of the surface. Accordingly, the square roots of the preceding ratios give the relative molecular Wistances. This ratio ranges between 1.1 and 1.2. It follows that as soon as the molecules of a mono-molecular oil film are separated by from 1.1 to 1.2 their normal distances, they lose all power of lowering the surface tension of water. Conversely, as soon as the molecules are brought together, so that they are separated by 1.1 to 1.2 of their normal distances, they cause an abrupt and con- siderable fall in the surface tension of the water, making it practi- cally the same as if it were a large body of oil. For beyond this hmit the oil gathers into globules. (f) Correction to the value of the normal molecular distance: The measure of the molecular distance 1.10 yy, given above, corresponds to films at their greatest extension. The true distance in normal oil will be somewhat smaller, say 1.10/1.1 to 1.10/1.2 or 1.10 to 0.92 py. This corrected distance differs decidedly from the theoretical value, 1.18 pp, deduced from the measures of Perrin. Some day we will examine the cause of this difference. 1 Meeting of the Société de Physique, May 3, 1912, 270 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. (3) MAXIMUM THICKNESS WITH GLOBULES. (a) Method of measurement: This measurement is especially diffi- cult. After various attempts, I came to the conclusion that here the only certain method was to proceed by the extension of the film as in the previous case. In order to determine the maximum thickness, I isolate portions of great black spots (4.5 cm. in diameter) which have appeared very slowly from a thick sheet of oil (pl. 6). Then, first lightly powdering the surface, I enlarge it to its maximum extension. This operation is often hindered by the existence of very minute globules. In an instance where the globules were absent I noted that the maximum extension was obtained by about doubling the surface. It certainly was not tripled. We may say, then, that a film of oil at its greatest thickness, when the excess of oil has formed into disks in contact with it, is only about twice its least thickness. In other words, no continuous film will be stable on water when its thickness is greater than two molecules, whatever be the thickness of the masses of oil in contact with it. It will be necessary to await new measures before we truly know whether these films have a real thickness analogous to the maximum thickness without globules. That is, whether they are not formed of a layer of single molecules packed as closely together as possible. (6) Discontinuity maximum: We are now in the presence of the maximum of the discontinuity of oil films upon water. We may easily have upon the water disks a millimeter or more in thickness. I have noted, for instance, that a cubic centimeter of olive oil placed upon water already, heavily oiled forms a disk 30 mm. in diameter and having an area about 7 square cm. Its mean thickness is there- fore greater than 1 mm. and it is certainly 2 mm. thick at its central part. Despite this thickness, the disk is surrounded by water on all sides, kept in stable equilibrium by an absolutely invisible film of oil having a thickness one-millionth of that of the disk. A simple comparison will show how peculiar is this discontinuous equilibrium of oil on water: Let us imagine our film enlarged one- half a million times; then our oil film at its maximum thickness would be 1 mm. thick, and it carries instable equilibrium masses of oil whose thickness can reach and even surpass 1 kilometer (1,000,000 mm.) ! (c) Comparison with the black film of soap bubbles: I have already, in calling attention to the evolution of a thick film of oil newly formed upon water, spoken of the constant appearance of black circles which grow larger and larger and merge finally into a continuous surface dotted with globules. It is odd that physicists OIL FILMS ON WATER AND MERCURY—DEVAUX. oTe have not been struck long since with the resemblance between these “holes” in the oil films and the black spots of soap bubbles. The mode of sudden appearance, the circular form, size, and progressive enlargement are very similar, and each hole is really occupied by an oil film whose thickness is comparable with that of the black spot of the soap bubble. The holes in the oil film are, it is true, always more numerous, and further, they finally become surrounded with droplets and then flow together (pls. 3 and 4). In reality, soap bubbles often show several simultaneous black spots, especially just before rupture. Further, and which is of special interest, Herbert Stansfield* has called atten- tion to black spots in soap bubbles accompanied by collars of disks and granules which correspond to what occurs with oil films, only, since the soap bubbles are never horizontal, gravity necessarily pulls the thick portions away from where they appear. The confluence of the spots is not then peculiar to oil films. The phenomena in the two cases are the same, the differences aris- ing from the changed conditions under which the films are formed, an independent and two-faced skin in the case of a soap bubble, a skin adherent to and supported by water in the case of the oil film. Accordingly, the study of the evolution of oil films throws light upon the final stages through which a soap bubble goes when it does not break. It becomes reduced to a black, very thin film, dotted with thick portions, either circular disks or droplets. Further, similar, very large, black spots have been obtained in the films of soap bubbles by Reynold and Rucker? in their beautiful researches made between 1877 and 1893. Upon these films they determine the thickness of the black spots which were all found sensibly equal and equal to about 12 yu. Johannot? later showed that films could exist having a thickness one-half as great, or 6 py. We can now compare the thicknesses of oi] and soap bubble films. In both instances we have black films formed from much thicker ones. Black films of oil with a maximum thickness of 2 to 3 uu. Black films of soap bubbles, maximum thickness of 6 to 12 py. These thicknesses are of the same order, Oil films are certainly always at least one-half as thin as the thinnest soap-bubble films. This important difference must be due to the fact that in the case of oil films on water there is only one free surface. 1 Proceedings of the Royal Society, 1906, p. 311. 2A. W. Reynold and A. W. Rucker, Proc. Roy. Soc. of London, 1877; Phil. Trans. ditto, pt. 2, 1881, 1883; Phil. Mag., vol. 19, 1885; Phil. Trans. Roy. Soc. of London, II, 1886; Wied. Ann., vol. 44, 1891; Phil. Trans. Roy. Soc. of London, vol. 184, 1895. 3 Johannot, Phil. Mag., vol. 47, 1899. bo 72 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. TABLE OF RESULTS. The following table gives a summary of the previous results and allows us to make useful comparisons. THEORETICAL REPRESENTATION OF BLACK FILMS AND OF MOLECULES. Greatest and least thicknesses of stable oil films expanded upon water. The thicknesses are multiplied by one million (1 mm. represents 1 pp.) 1.13 42 Theoretical size of oil molecules (trioleate of glycer- ine),! calculated from Perrin’s data. 1.10 42 Minimum thickness of a stable oil film found ex- perimentally. 1.15to Maximum thickness of a stable film without glob- 1.53 pe ules, or the minimum thickness of a film with globules, found experimentally. Black spot of oil films. 2to3 yu Maximum thickness of a film in stable equilibrium with great globules or with masses of oil of 1 mm. or greater in thickness. 6 ue ist minimum thickness of film of soap-bubbles. Black spot of soap- bubble films. 12 wy 2nd minimum thickness of films of soap-bubbles or maximum thickness of the black spot. Tana V. OIL FILMS ON MERCURY. Oil placed on mercury shows very similar results to those obtained upon water.? There is still a very sharp limit to the extension, and the thickness of the films at the limits is sensibly the same. When the oil is abundant enough, it forms a thick colored film which grows rapidly with the production of black spots surrounded with globules (pl. 7) and finally becomes a very thin film dotted with droplets. Other liquids (sulphuric acid, soap water, distilled water) give upon mercury analogous growths. We have therefore here.a very general class of phenomena.’ VI. CONCLUSIONS. We see now that a concept which at first seemed chimerical—that is, the reduction of substances to perfectly homogeneous films only one molecule in thickness—has become an experimental reality. And in- 1 See Devaux, 1. c., November, 1912. 2Deyaux, Journal de Physique, November, 1912. 3 Karl Fischer in his inaugural dissertation (Die geringste Dicke yon Fliissigkeitschich- ten, Miinich, 1896), studied the extension of two oils and other liquids upon mercury. He gives numerous measures of the thickness of films before their rupture. The thin- est had thicknesses less than 3 mz (rapeseed oil) and 1 gz (sulphuric acid). ‘sjo[dorp o1R O10} PUB OID, ‘SmMLY pasny YOR[G Bais JO posodwmood oie YAOM YoU OY} UL ssurmedo oud ‘W1Ilq MOIH_ | AYSA V AB AWIL SNO7T V Y314SV GSWHO4 ATIVYANSS SV 110 BSAIIO JO YYHOMLAN LV3Y5) ‘9 ALVid “‘xneaeg—'E16| ‘Hodey uRiuosy}IWS Smithsonian Report, 1913.—Devaux. PLATE 7. FILM OF OLEIC ACID UPON MERCURY. COLOR, VIOLET-ROSE (140 m2). The surface of the mercury had already received a drop of acid which had entirely con- tracted into droplets. The new drop expanded very slowly with clearly defined thick bor- ders. These borders have already been transformed into chaplets of great drops such as are always found about the black spots which appear at various moments in the expansion of a film. OIL FILMS ON WATER AND MERCURY—DEVAUX. 273 deed these phenomena work spontaneously and are visible to you all whenever a drop of grease falls upon the water in one of the ordinary plates from which you eat, so that nothing is more common and banal than these extremely thin films. The formation and stability of these films are automatic. The stability is so great that it is possible, without breaking the film, to distend it—that is, to separate progressively the molecules—until their reciprocal action is entirely destroyed, an operation which we could not perform upon liquids in bulk without leading immediately to rupture. With our films, however, this is a most simple operation and always successful; it is only necessary to increase the free surface occupied by the film upon the water or the mercury. Thus we have become acquainted with the fundamental fact that the extension of the oil film is limited. As soon as the molecules are separated by a distance greater by one to several tenths of their normal distance they lose all reciprocal action, for they no longer diminish the surface tension 1 of the water. We have called this phase the maximum extension. Conversely it suffices to bring them together, by contracting the sur- face slightly, in order to see the effect of the oil upon the surface tension of the water reappear and increase rapidly, so that the ten- sion passes rapidly from that of pure water to nearly that of oil. These facts allow us to enter directly the experimental study of the field of molecular action.? They allow us to catch a glimpse of other mysteries to be discovered, other marvels to contemplate, and to delve into that domain of invisible elements of which visible mat- ter is composed. The little drop of oil has much more to show us. Who knows, indeed, but that it will bring us before long phenomena of the great- est importance, yet which at present we can not foresee ? +A curious exception is found in oleic acid and in soap, the molecules of which when stretched over water can be separated some ten times the molecular distance. Devaux, I. c.,, 1904. “M. Brillouin so stated in the appreciation which this: professor of the Collage de France gave upon my researches at a meeting of the Société de Physique on the 3d of May, 1912. 44863°—sm 19183-——18 edt if ‘Aidainatele aR “gna odt gailered ‘ads sit Fides --volobem 1 aiid iatinnsr gest ole ge. doide qolie qe {opyaxiesb praanies Re | an’ pi pagsttt paibanl, saat 1 te, tained nie ime at ce i hi - * pe . cs oy pre ts 7 ota ws Ae ; Feit fe! BAthy ne ts 5 eae etree one oa gee serine. pict nietae “ie rae rates bo erer y= ve 9h ts aoeaborut aN: a oa qo 9p plays al aps WATER AND VOLCANIC ACTIVITY: By ArTHUR L. Day and E. S. SHEPHERD.’ [With 11 plates. } GREEN'S VIEW THAT THE KILAUEA EMANATION IS ANHYDROUS. In a book,’ now little known and rare, William Lowthian Green, a distinguished Englishman, long in the service of the native govern- ment of the Hawaiian Islands, writes as follows: What we mainly wish to contend for and to impress upon geologists—for reconsideration, at least—is, that it may be a mistake to assert, as is so often done in the most positive manner, that water and steam are inseparably con- nected with voleanic action. On the contrary it would appear that elastic vapors have nothing to do with the liquidity of the Hawaiian basic lavas, and that as a matter of fact they do not seem to come up with them from below, whilst the basie minerals themselves give no indications in the main eruptions, of having been in contact with water, highly susceptible as they are, to such an dnfluence. Mr. Green was not only a keen observer of the manner of operation of the physical forces which participate in the volcanic activity to be seen in the Hawaiian Islands, but his opportunities for studying such phenomena were quite exceptional. His conclusion, supported as it was by many facts of observation, has therefore demanded, and indeed has received, consideration at the hands of geologists gen- erally, although until very lately no one has been willing to consider it as having any application to volcanoes outside Hawaii. BRUN MAINTAINS THE SAME VIEW. More recently Albert Brun, a chemist of Geneva, Switzerland, has offered data‘ (apparently without knowing the werk of Green) gathered from a great number of active volcanoes with intent to prove by analysis of the gases which he collected that water plays 1Reprinted by permission from Bulletin of the Geological Society of America, vol. 24, pp. 5738-606, pls. 17-27, Dec. 16, 1913. - 2Read before the society Dee. 31, 1912. 3 Vestiges of the Molten Globe, pt. 2, 1887, p. 82. “Recherches sur ]’Exhalaison Voleanique. Geneva, 1911. 276 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. no part in volcanic activity. His words are as follows (p. 249, fol- lowing a detailed statement of reasons which will be considered below) : Il est done parfaitement certain que le volcan paroxysmal werhdle pas deau. La preuve est faite. Le grand panache blanc est composé de particules solides et anhydres. Il faut done que la théorie aqueuse disparaisse de la science. (The italics are Brun’s.) Except for these two conspicuous instances, students of vuleanism have generally concluded! that water is usually if not always the chief agent in volcanic activity. It is not our purpose to discuss this question at this time except in so far as it may find application in the voleano Kilauea on the Island of Hawaii, but this volcano provided all of the material for Green’s discussion and a very essential portion of that offered by Brun. It will therefore be of interest to record some observations made in the course of an extended study of this volcano by the writers during the summers of 1911 and 1912. The purpose of these studies is to obtain definite information about the character of the chemical re- actions which take place in an active volcano, and in particular to determine the role played by the gaseous components, which are very important factors in both its chemical and physical activities. In many studies of volcanoes the gases have been allowed to escape entirely, while in others they were not captured until the nature of the components was so much altered by oxidation or otherwise that their identification, to say nothing of the determination of their relative proportions and the character of the equilibrium existing between them, has remained uncertain. On these broader questions, which are laboratory problems, most of the work still remains to be done. It is, however, quite possible to offer evidence on the partici- pation of water and of some of the other volatile ingredients in the activity of Kilauea in advance of this study, which may require some years before all the questions which have been raised are satisfac- torily elucidated. DISCUSSION OF THE OBSERVATIONS OF GREEN AND BRUN. First let us review somewhat briefly the observations which led Green and Brun to the same novel conclusion, that water has no part in the volcanic activity of Kilauea. In the case of Green such a 1G, Poulett Scrope: ‘‘ Volcanoes,” London, 1872. John W. Judd: “ Volcanoes, what they are and what they teach,” London, 1881, James D. Dana: “ Characteristics of volcanoes,’ New York, 1891. A. Geikie: *‘ Textbook of geology,” vol. 1, London, 1903. S. Arrhenius: ‘ Lehrbuch der Cosmischen Physik,” Leipzig, 1903, It should perhaps be added that some have expressed the opinion that the importance of water has been over- estimated, without explicit denial of its participation in volcanic activity. (See, for example, J. G. Bornemann: “ Ueber Schlakenkegel und Laven, ein Beitrag zur Lehre vom Vulkanismus,” Jahrb. d, Kgl. pr. geol. Landesanstalt, u. Bergakad, 1887, p. 230.) WATER AND VOLCANIC ACTIVITY——DAY AND SHEPHERD. 2%77 review is not altogether easy. His reasoning is based on deductions from many phenomena, such as appeal to an observer on the ground; great lava streams without a trace of vapor rising from them; a condition of great activity in the lava pit of Halemaumau (the only portion of the Kilauea Volcano now continuously active), with hardly a trace of any cloud above it; a rather conspicuous difference in character between the Halemaumau cloud (when there is one) and the clouds which arise from numerous steam cracks in the coun- try round about, etc. Perhaps the chief factor which clinched his conclusion was the fact (which we also observed) that there are times when a magnificent cloud rises from the active basin, separated by but a day or two from periods when practically no cloud can be seen, and this with no apparent change either in the character or amount of activity visible in the basin. He therefore concluded that if steam was the moving force, and if the great white cloud was the manifestation of that fact, its presence must be expected on one day: as much as on another in which the same gas and lava condi- tions appeared to prevail. He was also able to discover no diminution in the liquidity of the ‘lava, either in the crater or in the great lava streams during those periods when no cloud was seen, and therefore no casual connection between the presence of the gases and fiuidity of the lava. Had it occurred to Green to try to remelt some of the solidified lava after the gases had escaped, this last puzzling question would have been clearer to him, for the crudest effort would at once have revealed the fact, which since then has often been noted, that these lavas, when reheated to the temperature prevailing in the lava lake before solidification, remain quite rigid—the characteristic fluidity has departed with the escaping gases. Brun’s statement of his observations at Kilauea is more explicit. In particular he offers six definite reasons for believing that steam is not present either in the lava basin or in the cloud above it. They are these: (1) The cloud arising from the crater does not evaporate in the sun as do the clouds arising from neighboring cracks after a rain, but can be seen floating majestically away often for 20 miles or more. (2) No rainbow or other optical phenomena can be detected in the cloud arising from the crater, although rainbows are abundant enough in the vicinity under appropriate conditions. (3) If the cloud were of steam emerging from white-hot lava, there should be an interval of a few feet between the point of emer- gence and the beginning of condensation (like the dark space imme- diately in front of the spout of a steaming teakettle) in which the steam should be invisible. No such dark space could be seen. 278 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. (4) As the cloud rises past the rim of the crater on the leeward side, the walls about the crater, being comparatively cold, should be wet with the condensed vapor, Whereas in fact these walls remain quite dry. (5) A train of glass tubes was lowered over the rim of the crater for a few yards on the side where the cloud was emerging, and through these tubes (some 250 feet distant from the nearest liquid lava, it may be remarked) air and the vapors carried by it were pumped for several minutes, but no trace of condensed moisture appeared on the inside walls of the tubes. Examination with a hand jens revealed the fact that the tube walls were quite thickly covered with crystallized salts, some of which were stated to be hydrates or to be hygroscopic, but this was deemed to be due to original moisture (!) carried on the tube wall before the beginning of the experiment. No analyses of the gases or of the solid salts are given. (6) A dew-point hygrometer carried along the rim through the smoke cloud showed a lower humidity within the cloud than in the clear air just outside of it. Before proceeding to recount our own experience with these phe- nomena, it may be as well to express our belief that nearly all of these observations, both of Green and Brun, may be perfectly true as recounted above, and still offer no proof that the volcano exhales no water vapor. ° THE EXPLANATION OF THE VOLCANO CLOUD. Green’s observation that the great white cloud appears but inter- mittently may be explained by a somewhat closer observation of the conditions of formation of the cloud without assumptions of any kind about its possible water content. For example, we noted, dur- ing several months of constant observation, that the visible cloud does not rise directly from the surface of the liquid lava, but rather from cracks in the inclosing banks,’ shattered, as they always are, by alternations of heat and cold as the liquid lava rises and falls in 1 Cf. plates 6, 7, 8, and 11. Observations confirmatory of the conclusion that the smoke cloud when present does not rise from the liquid Java, but from the shattered floor and talus surrounding the basin, have been recorded by other writers. For example, Prof. W. T. Brigham, director of the Bishop Museum,, Honolulu, who for 50 years has been one of the most careful observers of volcanic phenomena in the Island of Hawaii, writes as follows: (Volcanoes of Kilauea and Mauna Loa on the Island of Hawaii, Honolulu, 1909) : Page 28: ‘* * * It should be noticed how small the supply of steam in the active outpour of Kilauea really is.” Page 28: “ When the pit is empty of molten lava, the smoke is often most abundant.” Legend to plate 45: ‘Lava pool below the rim of Halemaumau. * * * Little vapor rises from the portion which is active.” Legend to plate 50: ‘‘ There is little escape of steam from the lake surface.” William Lowthian Green (Vestiges of the Molten Globe, vol. 2) writes (p. 170): “Smoke, vapors, and gases seem to arise from the orifices of eruption and orifices in the neighborhood of molten lavas on Hawali, and not from the lavas themselves.” WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 279 the basin. When the lava is high enough to completely flood the floor of the basin, these cracks are closed and all the gases emitted emerge directly from the surface of the lava into the atmosphere and have the temperature appropriate to the surface of the liquid (1,000° to 1,200° centigrade). At this temperature the gases (sul- phur and hydrogen, for example) burn promptly on contact with the oxygen of the air and remain nearly or quite invisible. A thin blue haze can sometimes be distinguished above a bursting bubble + when conditions are exceptionally favorable, but this haze is so thin that spectators watching for it from the rim will generally disagree about its existence. This is the condition of no cloud (pl. 1) described by Green, and does not in the least suggest either a change in the composition or a diminution in the total quantity of the gases given off by the volcano. When the lava level in the lake has fallen 10 or 20 feet (which is an almost daily occurrence and often takes place within an hour), only part of the gases set free come from the free surface of the lava, and considerable quantities now appear through the shattered floor surrounding the basin. The gases bubbling out from the lava basin remain as transparent as before and for the same reasons, but the gases appearing from the cracks in the floor and from the surround- ing talus are now cooled in passing through the cracks to such an extent that they no longer burn on reaching the oxygen of the air. Free sulphur is then set free in considerable quantities, unburned; this we were able to collect without trouble, both at the point of emergence and on the crater rim. It is this finely divided free sul- phur which is mainly responsible for the beautiful white cloud (pl. 2) above the crater and not crystalline chlorides, as supposed by Brun. In fact only a minute quantity of chlorine or its salts (less than 0.02 per cent) could be found in the emanations from the Kilauea basin during the period of our visit. Our observation of the appearance and behavior of this cloud is therefore in full accord with the observations of both Green and Brun, so far as recorded, but there is nothing in the facts thus estab- lished to show whether the sulphur is accompanied by water vapor or not. Herein is also to be found a sufficient explanation of Brun’s ob- servations—(1), (2), and (3), page 277, that the cloud when present does not evaporate after leaving the crater, that it gives no optical phenomena in sunlight, and that it is immediately visible as it emerges from the floor cracks and talus without a transparent zone separating the point of emergence from the visible cloud—results which would be expected if the cloud consisted only of steam, but not if it contains much sulphur. 1Cf. Frank A. Perret: “The circulatory system in the Halemaumau Lava Lake during the summer of 1911.””. Amer. Journ. Sci. (4), vol. 35, 1913, p. 341. 280 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, BRUN’S HYGROMETRIC OBSERVATIONS. The remainder of Brun’s observations of the apparent absence of water vapor may find appropriate explanation in the fact that they were made in an unsaturated atmosphere (as shown by his elaborate records of the hygroscopic state of the air during his observations) at a distance of more than 250 feet from the point of emergence of the gases, and the further fact that the cloud not only carries sulphur, but two of its oxidation products, SO, and SO,, both of which in these circumstances are effective drying agents. It may very well happen that water is given off in considerable amount by the volcano and yet remains invisible; for, in addition to the portion disappear- ing as vapor in the unsaturated atmosphere,’ a considerable addi- tional quantity will condense about the finely divided sulphur par- ticles, serving as nuclei of condensation. Furthermore, in our opinion, Brun’s explanation of what he deemed to be crystals of hydrated salts in his vacuum tubes and in the pipe line through which his gases were pumped is a somewhat fortuitous one, and certainly leaves an element of reasonable doubt whether their presence was entirely due to moisture carried by the tubes them- selves. The very care exercised by Brun would seem to make this unlikely except for the fact that it was offered by Brun himself. If it could be shown that these hydrous salts were regular inhabitants of the sulphur cloud, the comparative dryness of the cloud would also find ready explanation. Brun’s final contention (sec. 6, p. 278) that a dew-point hygrometer carried along the rim of the crater shows a lower humidity within the cloud than in the clear air immediately outside of it appears to be open to serious criticism from the physical side, although if one may judge by the space given to these observations in “ L’Exhalaison Vol- canique,” this is the point which Brun himself regarded as the most convincing observation of all. It appears to be a matter of grave doubt whether the readings of a dew-point hygrometer in an atmos- phere containing SO, and SO, have any significance whatsoever, in view of the well-known affinity of these compounds for water. The cloud could hardly be charged with better drying agents than these under the conditions described; it might, therefore, a priori, be expected to contain less free moisture than the adjacent atmosphere which does not contain these drying agents. Furthermore, the effect on the dew-point apparatus itself of exposure to the cloud contain- 1 Prof. J. P. Iddings, Prof. H. D. Gibbs, of the University of Manila, and several chem- ists from the Philippine Bureau of Science have observed gaseous emanations rising in great volume near the volcano Taal, which were found to contain large quantities of water and yet gave no trace of a cloud. (Unpublished records of the Bureau of Science, Manila, P. I.) "M1R948 JO APOIO o1B pur qd ay} Surpunoaans syouso oyy worl ynq ‘JIS Id AMO oy} UIOI] OU ASTI SpNOo [[BUIS OY, “PYOUS WoIy 9d1J NBUINUTE[VH JO yd 9AT}OB JuOsead oY] SUIMOYS “(OL6BL Uy) A1NC) YNOHVNSM) WOkS YALVYD VANVIIYM AHL SO MSIA OINVYONVd VW *| ALviad puaydeys pue heg—'¢16| ‘Hoday ueiuosyziws ‘VY Si oY} 1V 9d9UBISIp Oy} UT Uses SI ROT BUNBIT “pnNoypo oeyous [nJWNRAq 94 SurmMoys (CGI Se Aaliaip) ASNOH ONVOIOA SHL WOYS YSLVYD VSNVIIY JO MAA OINVYONVd Oo 31LV1d ‘pisydaus pue Aeq—'¢ 6 ‘Hodey URIUOSU}IWUS WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. Q81 ing SO, and SO, may be a factor of considerable significance. The first reading of the instrument might well be approximately correct, but subsequent readings would surely all be subject to the effect of uncertain amounts of SO, and SO, carried by the instrument in con- sequence of the first exposure. This would have the effect of render- © ing all the subsequent readings of the series quite valueless as a meas- ure of the water content either of the air or of the cloud. In order to support the view that the atmosphere within the cloud containing SO, and SO, is necessarily drier than air which does not contain these substances, several measurements of dew points were made by us in an appropriate laboratory apparatus, of which the results will be found in the table below. The first column contains the dew point of air at varying degrees of saturation; the second column the dew point of the same air to which 1 per cent of SO, (air + 1 per cent SO, is still respirable) has been added. All obser- vations are in duplicate. Observations of dew points. Air of ran-| The same dom water | air + ae Difference. content. cent SO2. | | ° ° eo 2 6.4 —0.8 7.0 5.8 —1.2 19.2 18.1 —1.1 19.4 18.4 —0.9 20. 4 17.5 —2.9 20.2 18.5 —1.7 21.6 19.7 —1.9 PA it 19.4 —1.7 21.5 19.0 —2.5 21.5 20.4 —1.1 Dew-point observations in the nature of the case can make no pre- tensions to high accuracy, but the effect of charging the air with a very small quantity of SO, is shown most convincingly. The effect of the addition of SO, would have been still greater than that of SO,, since it forms H,SO,, a notable dehydrating agent; but this effect is somewhat more difficult to examine experimentally and so was not undertaken; indeed, it was unnecessary, in view of the fact that the point at issue is abundantly proved by the observations con- tained in the table above. Brun has therefore proved no more with his hygrometer measurements than that the great white cloud does not consist entirely of water vapor, but it is not possible to estimate the percentage of water contained in it from any figures based on dew-point determinations under the conditions which he describes. From this evidence it appears clear that the observations of fact noted by both Green and Brun may for the most part be precisely as 282 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. described, and still the conclusion that water is not exhaled by the voleano Kilauea remain in doubt.* AN ATTEMPT TO COLLECT THE VOLCANO GASES BEFORE THEY REACHED THE AIR. Be that as it may, in our effort to obtain samples of the gaseous emanations from Kilauea for further study in this laboratory, it was au matter of very great importance to us to endeavor to establish the facts in the case without the aid of inferences of the character above outlined. We therefore entered on a long study of the habit of the volcano with the purpose of going down on the floor of the crater directly adjacent to the liquid lava, there to collect gases before they had come in contact with the air at all. In the interval between May 1, 1912, and January 1 following but two favorable opportunities for such an undertaking occurred, of both of which we endeavored to take advantage. On the first occasion (May 28, 1912) a column of liquid lava had worked its way up through the shattered floor adja- cent to the large active basin and formed an active lava fountain there several feet in diameter. Through its own spattering this fountain quickly built for itself an inclosing wall or dike. When this dike had grown to a completely inclosing dome (pl. 3), the gases dis- charged by the fountain were free to escape only through narrow slits in the dome, and there they could be seen at night burning fit- fully, with a pale blue sheet of flame, thereby demonstrating (1) an excess pressure within, and in consequence (2) that the gases re- leased from the liquid lava first came in contact with the air on emerging from these cracks in the dome. We accordingly made the somewhat difficult descent into the crater without mishap, and two crates, each containing 10 glass tubes of one-half liter capacity each, arranged in a continuous series, were then lowered down to us. To one end of this series of tubes a glass pipe line was attached, which led directly into one of the cracks of the dome (see pl. 4) through which the gas was escaping. The last link of the pipe line consisted of an iron tube extending into the dome about 12 inches. This iron pipe was also lined with glass up to the very mouth of the crack, so that, except for the 12 inches of iron pipe within the dome, the gases came in contact with no sub- stance other than cold glass and a few pure rubber connectors, which were made as short as possible by abutting the ends of the adjacent tube sections. Inasmuch as the liquid lava contains nearly 10 per 1The chemical and physical tests offered by Brun in support of his conclusions (5) and (6), page 278, are also somewhat inconclusive. For example, he tests for chlorine with a silver nitrate solution in an atmosphere containing S, SOs, and SOz, and notes that it immediately becomes clouded, but mentions no test to ascertain whether it was the chloride or the sulphite which was thus precipitated. Similarly, he nowhere offers a chemical analysis of these particular gases which he collected in tubes at Kilauea, but contents himself with presenting two analyses of other gases pumped from lava fragments reheated in vacuo some months afterwards. *(AYSL 94 UO) VYRl BAB 9} 0} dDUAIATOI WIA “SIGBT ‘8Z ABIY UO pazoa[[Oo a1OM SasRS YOLYM Wor (T) aTMOp 94] Jo UOMTsod ay) aIBAISNTIT 07 ydersojoyd [BUS B ULOL] pasiepugy (SL6L ‘8G AVIN) SWOG SHI SO NOILISOg 43; ERE /ala| *pisydays pue Aeg— 161 ‘Hodey uejuosyyiws ‘duind pur saqu} surjvoa[foo ay} YIM dayyosoy “Oo y v. 3, OY} UO SUIGQN) JO OUI 9Y} ‘po}Va[[O9 a4OM SoSBS YOLLLM ULOdT OULOp aly) SULMOUY "(SLEL ‘8G AVIN) AVWAVWAIVH ‘Lid 3AILOW 3HL NIHLIM MIA “p ALW1d *piaydays pur heq—e16| ‘Hodey uejuosy}iws WATER AND VOLCANIC ACTIVITY—-DAY AND SHEPHERD. 283 cent of FeO, the momentary contact of the gases with the oxidized surface of the iron was not accounted a serious disturbing factor. The other end of the tube system was connected to a piston pump about 4 inches in diameter, with a displacement of about 24 liters per stroke to insure a rapid passage of the gases through the tube system. The gases entered the pipe line at a temperature of about 1,000°. Their path was through the 12 inches of iron pipe, about 20 feet of glass tubing (pure rubber joints at 4-foot intervals), then through 20 collecting tubes and out through the pump at the back. The pumping was kept up for 15 minutes in order to make sure that the air originally contained in the pipe line and connecting tubes was dis- placed by the gases from the volcano, after which the pump and pipe line were sealed off with pinchcocks and the crates raised to the rim. In this pipe line water began condensing with the first stroke of the pump, and at the end of 15 minutes about 300 cubic centimeters had accumulated in the collecting tubes. It was clouded with free sul- phur, partly from the original emanation and partly from the action of the iron tube on the sulphur dioxide contained in the emanation. In arranging this experiment Brun’s conclusions were known to us, and accordingly we had provided ourselves with apparatus for col- lecting fixed gases only. We were wholly unprepared for any which might condense in passing through the collecting tubes. What we obtained, therefore, was a quantity of the fixed gases, which may be assumed to be approximately in the proper quantitative relation one to another, and water, the latter in considerable excess from the fact that it was not pumped through the tubes with the fixed gases, but condensed and remained behind, chiefly in the first three or four tubes. There is, therefore, no way to estimate from the results of this experiment the proportion of water to the total quantity of volatile matter discharged from the lava. Perhaps this should be regarded as a fortunate mischance notwithstanding, for we were thereby enabled to gather a quantity of water sufficient to establish its existence among the volatile ingredients exhaled by the volcano beyond the criticism of the most skeptical. Furthermore, the con- densing water by its accumulation in the first tubes served as a kind of wash bottle for the collection of any soluble material contained in the gaseous emanation. The next day we began preparations to meet the emergency thus thrust on us by Gate in the laboratory of the Hawaiian Volcano Research Association’ an extemporized mercury pump of the dis- +The Hawaiian Volcano Research Association is organized under the general super- vision of the Bishop Museum of Honolulu, and is in charge of Prof. T. A. Jaggar, of the Massachusetts Institute of Technology, to whom our most cordial thanks are offered for many courtesies extended to us throughout our work at Kilauea. Mr. I’. B. Dodge, an assistant in the association laboratory, accompanied us in the first descent into the crater, and Dr. H. O. Wood, who is in charge of the seismologiec work of the station, on the second, both rendering invaluable assistance in carrying out this difficult and some- what hazardous task, 284 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. , placement type and vacuum tubes especially arranged to meet the conditions which we had found. These tubes were of the same ca- pacity as the individual tubes in the previous experiment (one-half liter), but were provided with a long stem, on the remote end of which was blown a thin glass bulb. The plan was to attach these tubes to a pole of convenient length and to thrust the end carrying the thin bulb into the dome, where the heat might be expected to explode the thin glass immediately, permitting the tube to fill with the gases, and as quickly to seal it again by melting down the broken end. The tubes were dried in contact with phosphorus anhydride and the de- eree of exhaustion checked by electrical discharge tests from a small static machine. When a number of these tubes had been prepared and everything was ready for a second attempt, the top of the lava dome had fallen in and the liquid lava in the basin had gone down to such an extent that it offered no further opportunity to collect gases under conditions which should assure original gas with- out contamination from the air or otherwise. In fact no other op- portunity offered until December 4.1 THE SECOND ATTEMPT TO COLLECT GASES. On December 4, with the lava surface 360 feet below the rim, and therefore even less conveniently accessible than on the previous occa- sion, a similar dome formed directly on the border of the lava lake, and the second attempt was made to collect a quantity of gas—this time in the vacuum tubes. In order that there might be no possible doubt. about the excess gas pressure within the lava dome, the descent into the crater was made at night, when the pale blue flame of the escaping gases could be plainly seen emerging from the crack in the dome. The manner of collecting the gases was exactly that which was planned and described above, and six tubes were filled with gas under these conditions. On descending into the crater to collect gases from the December dome, it was found that in addition to a long sht or crack across the top, from which the gases were discharging constantly, there was a second opening near the base which was not noticed before the descent, but which gave access to air at the base of the dome and thus behaved like an air blast in a furnace. The gases were therefore partly burned within the dome instead of outside, and the tubes, which were filled at the upper opening, were accordingly found to contain chiefly burned gases—that is, the free hydrogen had become water, the free sulphur had burned to SO., the CO appeared as CO.,, ete. Although the identity and something of the relation of the gases discharged from the basin of Halemaumau can be established from a 1In the meantime one of the authors (Day) was obliged to return to Washington, leaving the other (Shepherd) to finish the task alone. WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 285 study of the material collected in May, the determination of the exact proportion of water to the other gases present must await another favorable opportunity. It may perhaps be added that a complete equipment for another attempt lies ready at the laboratory of the Volcano Research Association on the crater rim, but the lava lake disappeared completely from view soon after the December descent was made and has not again reappeared. Although the continuation of the field studies must await the gracious pleainie of the most fickle of goddesses, it need not delay the prosecution of the laboratory study of the relations between the gases already found or the preliminary discussion of the results thus far attained. Moreover, in the discussion which follows, evidence will be offered that the composition of the gases varies within considerable limits, so that the precise proportions of the gases which go to make up the exhalation at any particular moment may prove to be of less importance than was at first believed. CHEMICAL STUDY OF THE MATERIAL COLLECTED. From a physicochemical viewpoint, the study of volcanic activity centers first on the nature of the participating ingredients, then on the condition of equilibrium or the progress of the reactions taking place between them, as the case may be. At the time of our two visits all the three states of matter—gaseous, liquid, and solid—were found represented. Gases were emitted constantly in great volume, and displayed nearly all the great variety of cloud forms which have been so frequently described in volcano literature except the violently explosive type, which has been rarely or never seen at Kilauea since the advent of the white man (1820). There was a liquid lava basin of oval shape some 600 by 300 feet, inclosed by a lava dike or rampart built up from the surrounding floor of the basin by the tumultuous spattering and splashing of the lava lake (pl. 5). Both floor and rampart are frequently overflowed when the lake is high, and again great masses of it fall into the lake and are redissolved when it is low. The fioor of the pit at the time of our first descent in May, 1912, had been completely overflowed but three days before and was rea- sonably level. The fresh lava had solidified to a depth of some 10 inches and was abundantly solid to walk on, but was still uncomfort- ably hot and the cracks were still glowing. Surrounding this floor are the walls of the pit, some 200 feet high at the time of our first descent and made up of the exposed edges of successive earlier overflows (pl. 6), which individually rarely ex- eeeded 2 or 3 feet in thickness. The (Halemaumau) pit as a whole was about 1,500 feet in diameter, roughly circular in plan, and with nearly perpendicular walls except for the talus pile ‘at the base, which extended about half way up the wall. All these dimensions vary 286 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. somewhat from day to day and considerably from year to year with the state of activity in the basin. The appearance of the lake and its surroundings is perhaps best shown by a photograph (pl. 7) made from a slight elevation above the floor of the active basin on May 23, 1912. ANALYSES OF THE LAVA, The composition of the liquid lava in the lake and of the solid floor of the Kilauea crater near the Halemaumau pit may be seen from analysis la and 16, which follow: TABLE 1. A Analysis 1a, Analysis 1b. Lava from floor of Kilauea: Forty Lava dipped from Halemaumau to 50 per cent glass; 5 to 10 per cent July 23, 1911. Glass, with 1 per cent olivine; 5 to 10 per cent feldspar’ feldspar and trace of crystals of either phenocryst; rest very fine crystals. magnetite or pyroxene. Index 1.605, (Merwin.) lining of bubbles slightly higher. Percent. ( Merwin.) SSC Gp ies TL ah ea imate 50. 07 Per cent, D4 nk pes ale te tr a rot rs ato Ld 13.32)" SIO 2 ee eee 49. 74. Fe.O;___- ER Se ee eee 1. 92 AloOgi) 2 SiR E AREY Sue eae 12. 36 OBC RED SET ere MEETS Ta eae 9, 28 Peg see ee ag 88 ee hee ree 1, 64 Rie et! 4, nese ee ONY Mie@a” at alin ye Eee er (EN ESN SS SAR SP Ta 2 EE 10.,64. -; MgO). eX... ee eee eee 8. 83 ROOD ete (O) ee OE eel 2 ee Oia ae eB ks Gu CO) Miss Wen Uh Lae ee 10. 88 LSE) cs eT a a i ag SAS IN ei One Ses eae 2. 45 Did A Fi eal a a eal ech O° 49.0 SK Ost Se Poh ES ae 0. 55 DAG == it A Eo a a EE O22) MEO Re See Eo Ee ee ee 0.17 CO 5e5 I 20 2 A ee None: 44 LO st 2u ue ae ae 0. 05 AMOR Se ees ee ees are Di 10 (ROO? oe. Se ee ee eee None PAV Os ae A a NONE 4 RIO oye ee ee eae Se ee 2.49 LER Ope LR oS SA ae eee OP ZO AW ZO sae 2 Wis ae oa eee Trace. 1S ess carn lS a NODGS > 3PuOke a. a 0. 41 CO a ht Pl Sa a 0. 08 SO gh at Ses eee ee Trace lied. DReh sted Ree ees Bree eee eee NOME! OIE Pcey 2 ee eee 0. 10 So Sa ae Og a oe a 0. Tsp Wells 24s Le eee None OTTO PRUs SPIN: Ce SRNR «lee eae Oh .OB Se a 0. 04 (Min @ nee eee Bee ee O.16 Cr Ogee eee eee 0. 04 nC) Rea Eat es ee a 0:04 0 MnO 222222 2 eee 0. 14 TOV G lat elie SE eI None.) NiOw 22 UA ee eee 0. 05 Sr et LA P82 Trace. GBaOss! {oleae ) ae Trace LIST O ogee 2) SSL oe Os None) SrOQ.saeo2 cuca at) tee 0. 07 eee a ne lp a Sw None... isOc sah LeU ee eee ees None Awe Bom pin a sg el None.» VsQse. 22 ee eee 0. 02 MOO ies soko eet ates Oe eS Trace: . ‘Rare earths. 2.3 eee eee Trace. Teiition Tossa. et | eee 0:36." MOOs. en ee ee 0. 01 99. 96 100, 12 | After correction for Cl, ete___-- 99.89 After correction for Cl, ete..--- 100.08 ‘aINSOdX9 Ot] 10}}B SJUSWIOUT AVF BORE 9Y OUT [Tay eamiotd ayy Jo 19yU00 Of} FO IOT OYF OF OLATT B OXTP oy Jo uofrod VW “WMOYS TAAL SI BART 0] JO Surso}eds ay) 0} oNp OYIp SuIsopoUT oy ‘Foye 109) ¥ ATOIIpPEUIUMT TOAD OY) UITIIM USAR, “(CLBL ‘8g AVI) SONVY 3SO1D LV 3XV] VAY] SHL 4O MSA *¢ ALVId *preydays pue Aeg—'¢|6| ‘Hodey urjuosyziWs sa ‘BART OATIO“ OY} VAOGB IYOUS JO 9OUDSGB OY} OJON “41d 9} JO [[BA\ SuISO[OUT oy) Os[e SurMoyg “(ElL6L ‘6S ANN) SAONVY 3SO1D LV 3NV7] VAY] SHL SO MAA — agpte, - sete BE aS "9 31LV1d ‘paaydays pue Aeq— e161 ‘Hodey ueiuosy}iLUS WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 287 The sample 1b was dipped from the middle of the lava lake on July 23, 1911, by Mr. Frank A. Perret and one of the authors (Shep- herd), with the help of a cable and trolley, stretched directly across the center of the pit, and appropriate tackle. The sample la was taken from one of the recent overflows on the main floor of the Kilauea crater and may perhaps be 15 or 20 years old. The sub- stantial identity of the analyses with each other and with other recent analyses of the lavas of Hawaii* shows that no material change in its composition has taken place in recent years. The most noticeable feature of the new analyses is perhaps the presence of a small amount of molybdenum, which appears not to have been de- tected hitherto. The analyses were most carefully made by Mr. John B. Ferguson, of this laboratory, to whom we take this oppor- tunity to express our thanks. THE GASES AND DIFFERENT WAYS OF STUDYING THEM. The problem of collecting voleanic gases which are satisfactory from the chemical viewpoint is a much more difficult matter, as has been already intimated. Hot gases of more or less complicated com- position discharged from an active volcanic vent into the air undergo immediate and violent chemical and temperature changes, the conse- quences of which, with our present limited knowledge of gas relations at these temperatures, can be only partly inferred. It is therefore a matter of the first importance to collect the gases directly from the liquid lava or the explosive vents before contact with the air has given opportunity for these alterations to occur. It may very well be that the physical difficulties attending the collection of volcanic exhala- tions, particularly from volcanoes of the explosive type, will often make it impossible to obtain unaltered magmatic gases for laboratory study, in which case burned gases, or even very dilute mixtures of these with air, may prove to be the only products available for study. In this event the student must perforce bow to the necessities of the case, Something of the same cautious attitude requires to be maintained toward the study of the flame spectra of burning volcanic gases. The pocket spectroscope is primarily an instrument of preliminary recon- naissance in the field and is sometimes of value, but the pale-blue flames of sulphur and hydrogen are extremely difficult to analyze with the pocket spectroscope, and can not be distinguished at all against a bright background of solid or liquid lava. For this reason 1This expedition was sent out by the Massachusetts Institute of Technology (Prof. T. A. Jaggar) in the summer of 1911 for the purpose of securing a trustworthy measure- ment of the temperature in the lava lake. The record of the expedition has not been published. a A. Daly: Magmatic differentiation in Hawaii. Journal of Geology, vol. 19, 1911, p. 305. W, T. Brigham ; Loe. cit., p. 33. 288 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, a more elaborate spectroscopic equipment would not help the matter. Moreover, the gases are much altered or are in process of active alteration before any opportunity for identification is offered, and no estimate of the relative quantity of the various participating gases is possible by this means. Inferences from the chemical study of gases which have been burned by contact with the air while still hot and inferences from the spectroscopic study of the gases while burning therefore suffer alike from limitations of principle and should be resorted to only when the difficulty of collecting unaltered gas is insuperable. These reasons may serve to show why this somewhat elaborate effort was made to collect unaltered gases for laboratory study and why we are inclined to give greater weight to the results obtained from the study of such gases than to many of the earlier studies? of voleanic emanations, in which the gases had become altered through contact with the air or otherwise. The domes from which these gases were collected were built up by the lava itself on the floor of the crater (Halemaumau) and were both chemically and physically ideal gas collectors, being lined with fresh splashes of liquid lava of the same temperature and chemical composition as that from which the gas had just emerged. They formed at the level of the lava lake and, as could be plainly seen after the collapse of the domes, were directly connected with the lake by channels of liquid lava just below the surface crust. The collapse of the entire channel leading to the May dome is shown in plate 8, figure 1, in which an arrow (t+) has been placed to indicate the position where the dome stood. The May dome was under con- stant observation for several days and a considerable portion of the night immediately previous to the collection, during which time there was no cessation of the lava fountain spouting within the dome nor of the flames of the burning gases as they escaped through its cracks. Furthermore, as the larger bubbles rose and burst from the liquid Java within the dome, the jar could be felt on the floor where the collectors stood and the splash could be plainly seen through the cracks. — fie se ANALYSES OF THE GASES COLLECTED IN MAY, 1912. The following analyses were made of the fixed gases collected in glass-tubes on May 28, 1912, in the manner above described. ‘The statement is given in parts by volume. The tubes were numbered from 1 to 20 in the order in which the gases entered from the voleano. Allthe tubes contained condensed water (the first—pl. 8, fig. 2, containing nearly 100 cu. em.), of which analyses will be feund- on page 292. saasde, 1H. g., Wm. Libbey: Amer, Journ, Sci. (8), vol. 47, 1894, p. 371. ‘IaJOWIBIP UL Joo] OF INO SI arqqnq Sursing ogy, “punosrse10y 9y} ur BART Ador JO UOIBUIIOJ VY] PUB YS PUB IJoT YIOG MOYAVAO oY] OJON “(SL6BL io? AVIA) ALIAILOWY SLVYSGO|) SO GOlYad V NI 3JIOHM V SV 3xXV7] SHL SO MIA “LZ 3LV1d ‘praydays pue Aeg—¢16| ‘Hodey uejuosyyWS ‘SYSLVM SINVOTIOA GASNSGNOO0 SONINIVLNOO 38NL GNV G3L037700 3YaM S3SVD S3YSHM 3yV7 ‘sIoJ9UIN Us) 3 10 OOL JNOQ®B ST ‘OH Bl 94] Jo Ayyuenb sy A+Ppesuepuoo BUuTMOYg UNI’ UB SPU9}X9 SONSST PNO[Y 9Y} LOY M YOVIO oy} YJBVoOUS ‘“poOojs pRy oMOp ayy sey ooryd (f) SsUIMOUS “SISATVNW YOS AGVAY AYOL “(SL6L ‘So ANNP) -VuyOEdV] SHL NI | “ON 38NL JO MAlA—"S ‘SI4 G3L93T1090 3Y3AM S3SV5) YALSV SAVG SAI4 YOOT4 GSYSLLVHS SHL GNV 3aXNV7 JO M3IA—"| ‘OI4 °8 ALV1d *paaydaus pue Aeq—'¢e|6| ‘YH d 94 UBIUOSUPIWS WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 289 TABLE 2.—The gases from Halemaumau (Kilauea), May, 1912. [Percentages by volume.} Tube 1. | Tube 2. | Tube 8. | Tube 10. | Tubo 17. Wipe encanto so ase setae coos ac sales Ses esees THE INFLUENCE OF THE IRON COLLECTING TUBE. In the 15 minutes during which pumping was continued the short length of iron pipe which extended into the dome was partly de- stroyed by the joint action of the sulphur and SO,. Owing to the high temperature and the splashing of the molten lava, neither glass nor porcelain would have withstood the ordeal, and a tube of silica glass was, unfortunately, not available; so that iron appeared to be the best material at hand through which to reach the interior of the dome and to insure the capture of the gases at the temperature of emergence from the lava (about 1,000°) before any opportunity for cooling or contact with air had been given. The effect of this small section of iron pipe on the relations between the gases collected in the tube is not as great as might at first appear. The action of SO, on iron at this high temperature is quite vigorous, the iron going over to ferrous oxide and setting free the sulphur. But both these ingredients are present in the lava already, as may be seen from the analyses (Table 1), so that no new component. is added, nor is any new reaction precipitated through the introduction of the iron. It might be assumed further that the free hydrogen present would be partly oxidized to water in reducing the ferrous oxide formed from the SO, and iron (this is one of the reactions when these components are brought together at this temperature in the laboratory), but if this reaction has had a share in the disposi- tion of our bit of exposed iron we must admit its presence in over- whelming magnitude over the entire inner surface of the dome, which is everywhere lined with liquid lava containing nearly 10 per cent of ferrous oxide. The assumption of this reaction would therefore have the immediate effect of establishing the presence of water in quantity among the volcano gases and at the same time relegate the influence of the iron tube to a position of entire insignificance. There is still further evidence, if more is needed, that the local reactions set up by the iron are of subordinate importance only in their effect on the proportions of the gases collected, and of no effect whatsoever on their identity and chemical relation. Supposing these 44863°—sm 1913——19 290 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, reactions to have occurred as described, it is then a matter of straight- forward computation to show that if the known weight of iron which was dissolved away by the gases, both those which entered the pipe and those which merely played on its outside wall,t had reacted in this manner; and supposing further that all the products of the reaction, both outside and inside, entered the collecting tubes (which is obviously impossible), it would have involved pumping through the system some 225 liters of pure hydrogen as an equivalent for the iron consumed, and this still falls short of the quantity required to account for all the water collected by more than 40 per cent. More- over, if the attempt is to be made to account for all the water col- lected in our tubes through reactions requiring free hydrogen, it is altogether inconceivable that any such quantity of uncombined hydrogen is available in the emanation from the volcano. For if we were to assume that as much as 1,000 liters of volcanic gas (which is a very liberal estimate) passed into the collecting train in the 15 minutes during which the pumping was continued, such a quantity of free hydrogen (375 liters) would be equivalent to 40 per cent of the total composition, a quantity sufficient to form an explosive mix- ture on contact with air of such extreme violence as to change the entire character of the volcanic activity at Halemaumau. It is a fact of general observation that the bubbles of gas which come up through the liquid lava, even when they reach the enormous size of 30 feet in diameter, give no explosion whatsoever. We may therefore fairly conclude, both from the character of the reactions in which the iron might have a part and from the quantity of water collected, that the presence of the iron tube has no consider- able significance in relation either to the character or to the amount of volatile material collected. THE REACTION BETWEEN H. AND SO, OR CO,. To this reaction assumed to be going on between H, and FeO may be added another and much more important one in which the iron has no part. The free hydrogen set free by the volcano reacts with sulphur dioxide at 1,000° to give water and free sulphur directly. Tt will also be recalled that carbon dioxide and hydrogen undergo similar reaction at this temperature. This is the familiar water- gas reaction HCO, = "CO--ELO which has been thoroughly studied by Haber? and others throughout the entire range of temperatures found to prevail at this volcano, and may be accepted without limitation as an important factor in the ferrous oxide and about 8 per cent of sulphur. 2See, for example, F, Haber: “ Thermodynamik technischer Gasreactionen,” p. 158. Miinchen, 1905. WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 29] activity which we are studying. It follows directly from this that the chemical analyses of volcano gases offered by Brun in support of his conclusion that the exhalations from Kilauea and other volcanoes are anhydrous, also carry on their face the clear proof that his con- clusion is untenable. Neither CO, nor SO, can be associated with free hydrogen at temperatures in the vicinity of 1,000° without the formation of water. The two analyses offered by Brun of the gases given off on reheating the Kilauea lava show them to be chiefly made up of precisely these ingredients (loc. cit., p. 115) : Brun’s analyses of gases obtained from Kilauea lava when heated in vacuo. af 2. Ke pee ee Se TraAcesye Cl) si Rey see SS OO EA 5. 58 AS), al glo el ae a Lesh Gol 29) Cot pei ce Ml ch IRE d bein b OY Oe eel area. >, ee 50.8 | SOs ____ Bite Pear iatel oe Bes! i 4/2 47/7. CLG ean: Seeene ss SRR eee oe NT Bil) COR Se Sheree, Fis koe Sees ees, 69. 09 15 Eee Se ES EES TR al ee a 285 WC Oy ee. 2 BE ea ee 11. 60 J Ee Se aR i A SS ES eT a a 9 Kee? aK Oo (espe ey Sao LOE Si egestas ie, Wace ie gee ee 6. 10 Peg RTH! tkasy aa ae Sy 0.3 It is, furthermore, noticeable that the analyses here offered by Brun as representative of the gases emanating from Halemaumau do not in any way agree with the composition of the gas which we obtained from liquid lava. He finds, for example, in one analysis more than 7 per cent of chlorine in one form or another where we find 0.02 per cent or less, He obtained about 5 per cent of SO,, whereas SO, dur- ing our visit was perhaps the most notable gas evolved from this crater. THE RELATIVE QUANTITIES OF THE CONSTITUENT GASES. Leaving now the question of the identity of the gases discharged by the lava at Halemaumau, we should perhaps turn for a moment to the consideration of their relative quantity, which, as already inti- mated, is not so well established by our samples because of the unex- pected presence and condensation of the water in the collecting tubes. In addition to the presence of the iron tube, and its possible effect on the total quantity of water and of free sulphur collected in our tubes, which has been discussed above, our analyses of the gases (p. 289) are subject to a second limitation which is at once obvious. When the pumping had been completed, the collecting tubes each con- tained a quantity of the condensed water, in which the fixed gases are individually soluble in varying degree both during and after cooling. There is also some reaction between the gases and water. The long period which elapsed between the date of collecting the gases and their analysis in Washington after the close of the field season—nearly a year—gave opportunity for these readjustments to proceed practically to completion, The SO,, for example, has gone 292 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, over in part or altogether to SO, and gone into solution, and only two of the five tubes analyzed now show SO, as such. Moreover, the resulting acid solution may have reacted to a limited extent on the glass tube, and accordingly be responsible for all or a part of the alkalies, lime, and alumina shown in analyses of the water (table 3). PRELIMINARY ANALYSIS OF ONE TUBE OF GAS IN HONOLULU. For this reason some importance attaches to a preliminary and very hasty analysis of the contents of one of the tubes (No. 3) made but four days after the collection, for which the College of Hawaii most courteously extended the facilities of its chemical laboratory at Hono- lulu. This preliminary analysis was undertaken solely as a precau- tion against the consequences of a possible total loss of the material collected through accidents of transportation. Owing to the limited facilities, it was not possible to make a com- plete analysis; but in tube No. 3 shaking with water reduced the total volume of gas by 51.6 per cent, which may fairly be assumed to repre- sent the SO, in this particular tube. As there was a quantity of the condensed volcano water in the tube already, this merely reveals the quantity of SO, in excess of the quantity already taken up by this water, The carbon dioxide of this tube amounted to 39.8 per cent. but was probably contaminated with some SO,. The CO amounted to 5.5 per cent. The hydrogen and nitrogen could not be determined, but there was not enough hydrogen in the residual gas to form an explosixe mixture when mixed 1:1 with air. The water in this tube gave a very slight turbidity with acid silver nitrate and a slight pre- cipitate of SO,. This latter represents the amount formed in the tube in the time which elapsed between the collection and analysis (four days). This tube gave no test for titanium. Hydrocarbons could not be detected in any of the tubes. THE MATERIAL PRESENT IN THE WATER. The water which was collected in the first tubes of the series may fairly be assumed to contain practically all of the halogens. The analysis of this water is given in Table 3. TABLE 3.—Analyses of material contained in the water collected in the tubes. Tube 1. Tube 2. Remarks. Grams. Grams. DOE OLED EL RE Sto ae re ae As 2a ee ae 0.0214 0. 031 MPS. Fane dS ARELE S ERS. LEE Se 2 - 0102 -011 |]The major portion of these CaO rsa stte eet, aes ko ne, Fao i eran reel. 0120 -14 may have come from the Fe.O; 080 010 glass or from Pele’s hair. AlsO3 Pee ee eee eee we ee ewe te eee eee eee ewe cones Ul . Me FET eS PSS da sae . 220 . 206 epee. cours Se Eero. Sg fa es ae ee . 565 - 492 WWiktyss. AGS VA. SA... a SE . 0018 0 TST Waser ects: ak ea tciniore raw aie fc riot ee eee - 005 (2) oO | TotalisiasiSOguee ll: RSW. wee Se arses 480 508 | WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 293 It is not improbable that most of the alkalies, lime, and alumina have resulted from the action of the acid liquid on the glass tubing, but it is of the greatest importance to establish the fact that the en- tire quantity of gas pumped through the “wash bottle” yielded no more than 0.4 gram of chlorine. If this be calculated in the form of gas, 1t will correspond at most to 0.02 per cent, assuming that ap- proximately 1,000 liters of gas were drawn into the tubes. Fluorine seems to be present in about twice this quantity, but in no sense can these halogens be regarded as forming more than a very minor part of the crater exhalation. RARE GASES. In the progress of the analyses, after all the active gases had been removed from the several tubes analyzed, there remained an inactive residue which, of course, consisted mainly of nitrogen, but which might be supposed to contain traces of argon, helium, or other of the rare Inert gases, should any such chance to have been present in the volcano emanation. For the determination or detection of these sev- eral of the residues were brought together in a spark tube and ex- posed for several hours, in the presence of oxygen, to an alternating- current spark discharge of considerable intensity. When the volume of residual gas could no longer be diminished by this means, there remained a final residue of 75 cubic centimeters of gas, which was forwarded to Prof. R. W. Wood, of Johns Hopkins, who very kindly offered’ to make a spectroscopic examination of it for traces of the rare gases. The search yielded a decisive negative result. No lines characteristic of any of the rare gases could be found with the spectroscope, nor did exposure to charcoal at the temperature of liquid air leave any residue whatever. The gas examined was, there- fore, all nitrogen. Subsequently the residues (15 cubic centimeters) from another group of the tubes were treated in the same way and forwarded to Prof. Wood, who was again able to detect nothing but pure nitrogen. It appears to be definitely established, therefore, that the gases collected from Halemaumau in May contain nitrogen but no argon. This affords a most desirable confirmation of our belief that the volcano gases were successfully collected before they had come in contact with atmospheric air at all, and were therefore en- tirely uncontaminated either by reaction or admixture with it. It also offers support to the view that the volcanic nitrogen is not of atmospheric origin—to which further allusion will be made in the concluding paragraphs. 1 We desire to take this opportunity to thank Prof. Wood for courteously offering to examine these gas residues. The Geophysical Laboratory at Washington possesses neither the equipment nor the special experience necessary to undertake a spectroscopic study of this critical character. 294 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. THE GASES COLLECTED IN DECEMBER, 1912. From the gases which were collected in vacuum tubes on December 4, 1912, much less information is obtainable than from the May col- lection, in spite of the more elaborate preparations made for the second attempt. This was wholly due to the fact already mentioned, that the dome from which the December gases were collected proved on near approach to be an imperfect one, which permitted the en- trance of air and a partial combustion of the gases within the dome. Six individual vacuum tubes (two of one-half liter capacity and four of 250 cubic centimeters) were automatically filled and sealed off within this dome and were brought to Washington in safety, but were found on opening to contain mixtures of volcano gases and air, such as might be expected from exposure to the temperature at which they were collected (about 1,000°). There is, of course, no more rea- son for expecting the chemical reaction between the gases and air to have proceeded to an equilibrium than in the case of the reactions between the volcanic gases alone, whence the analyses of the gases contained in these tubes may be expected to show very variable proportions. In stating the analyses the free oxygen found has been subtracted, together with a corresponding portion of the nitrogen appropriate to the normal composition of air. Probably more of the nitrogen should have been subtracted as an equivalent for the oxygen taken up in the combustion of the sulphur products and carbon monoxide, but the amount would be difficult to fix in view of the reactions between the volcano gases themselves and it has not been attempted. The analyses at best add but little to the knowledge already obtained. TABLE 4.—Analyses of gases collected in December, 1912. [Percentages by weight.] Tube 2. | Tube3. | Tube5. COE Pe es eRe ee ens SE Seis cicteiale Cs sb SRL eeceh ees see ee es 49.6 33.7 45.4 IN ig eee Re ecient cichene vee eclatsis io otis: a aim wis SiS Siacw mee ehotarn alates area 24.1 32.1 21.3 Ree Rr eee ieee cote wis oda UV aceees ELM gees cB osmieags 26.2 26.6 29.7 PO ree eee tee ane Seiae MeN Ee Ee ele ee sais meinia oe acne Womens Salt matiee 7.6 S20 Cae ES yar at OP eames. IT nt card aad dias ee a eb eae wee Trace 0 .0 mt) .0 If we make the only available assumption, namely, that the oxygen which is now present as water, if it came from the air, must have left behind a corresponding amount of nitrogen, then the amount of nitrogen found in these three vacuum tubes is in every case two or three times too small. For example, in tube No. 2, if all the oxygen now contained in the water came from admixed air, there should have been at least 240 cubic centimeters of nitrogen in this tube WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 295 instead of 74 cubic centimeters, as actually found. There is but one conclusion, namely, that only the minor portion of the water found in the tubes was formed through reaction with atmospheric oxygen. Here again, therefore, we have corroborative evidence of water emanating directly from the liquid lava. None of these vacuum tubes gave a test for ammonia, which is not surprising, since the water collected in May showed only a trifling amount. With the possible exception of 5 milligrams of insoluble residue found in tube No. 1 of the May collection, ho titanium was present. The other tubes of the series yielded none on test. THE HOT EMANATIONS FROM CRACKS ABOUT THE HALEMAUMAU CRATER. It was thought desirable to collect and analyze the gases from a number of the hot cracks which occur outside the rim of the Hale- maumau pit (see pl. 1) for comparison with the gases exhaled from the liquid lava. One of the cracks forms an almost complete ring around the pit at a distance of about 150 meters from the rim. While this crack appears practically continuous, there are a number of points where the gaseous exhalations are much more voluminous than at others. The small steam cloud in plate 1 comes from this erack. The temperature of the gases obtained at points on this cir- cular crack and some 10 feet below the surface were quite uniformly between 190° and 200°. At the most noticeable of these “ hot spots,” locally known as the “ Devil’s Kitchen ” or “ Postcard Crack,” and situated northeast of the Halemaumau pit, the surface lava flows are much decomposed, and consist of a coarse, somewhat sandy mixture of calcium sulphate, alum, ferric sulphate, and much free sulphur. In the gaseous exhala- tion the amount of SO, occurring as such is relatively high, while CO,, SO,, and free sulphur are also present in large quantities. A vacuum tube filled at this point yielded in weight per cents: [Per cent by weight. ] EG) cae A Ta A RS a at ati ig eggs RG (6 2 | yee ee eeeM ess Dead tee 2 See ee es eS SE Sh 19. 54 Ty oa ed NB DE a tee an Nn ca SP ig in AONE eNO em Ee al oft (0b TMs) oot ee eg tse RR i oe oe ee ee 2 ee OSE SO,7_ = pues aa ees SS ORS es Pah a ES eh AS trea BS tar 37 Other tubes which were filled by pumping at this crack were found to contain fixed gases as follows: [Per cent by volume. ] ROC ee cr el Ae Ne a OE Shed de oo Stl, 3 Sk 5.8 0 SERIES SUES Ye gear SRST soe i pe hc Se oe age a ae Sees SESE: TT 18. 2 1 The total sulphur computed as SOx. 296 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. while the water (about 20 cubic centimeters) yielded: Gram. Ye a se acs A aa 2 0, 05138 | AS aa AG AE Lae IN ae i ES ee Ibe a . 0079 Fo el eg ce eg el Mt ree Ht 2 ha eee eS eg ey ola WHe2 S60 toe Se Ee ee eee 0 Another spot of great gaseous activity occurs in this circular crack near the terminus of the automobile road and southeast of the center of the active pit. The vacuum tube taken at this point yielded: [Per cent by weight. ] 0, 0s ye ie Sel ea eee re A RE tN Ea 8.12 OEP LE ST NN SEGA a Ue EE eb A oh SS 14. 58 BON ee aie er ee wh a AS a oe a Se eae 51. 20 1&0 nice AS SE RES OE Satan eee nee Be Dees Tyee RED Pee 25. 49 Oar Npewprg: shee whale Ses ee Or ey 2 ie Es lowed ate ge . 59 MO Babs iA Srey Ste ake AN eT Nh ee NI Fa see yay, LE undet The water contained in the tube which was filled by 15 minutes’ pumping at this point (amounting to about 15 cubic centimeters) yielded the following: Gram (CU oR a eet nee ee ee ee nee Ene Pom a OLS 0. 0298 LINE oP ih tS Tia Pet NN A eg a eR eres ce emmy Deny ee Ls Ds 0 ro as el ae Aiello eR pe a I ec EAL Les Te . 656 Fifty meters to the northeast of this point, along the same crack, the gas obtained was merely moist air, with a trace of SO, and uncertain traces of Cl. About 100 meters south of the terminus of the automobile road is a moist region, where the decomposed lava rock was found to be more or less saturated with sulphuric acid, the decomposition products being black rather than the bright sulphur yellow prevailing at the points above described. A vacuum tube taken in this region, which is again on the circular crack surrounding the pit and nearly due south of it, yielded : [Per cent by weight. ] Ree Pen ee 18.18 Me I i ae a 63. 85 eee ee er oe ee 7. 81 Ope ree tebe See ee a ee ee eee 5i Og 8 tad hee ol i et Oo be ee a 0 The water condensed in a tube filled by pumping at this point yielded about 3 milligrams of chlorine, but no flourine. With regard to the chemical products along this circular crack about the crater basin of Halemaumau, we can sum up by saying that water, although no doubt partly of meteoric origin, was always pres- ent at the time of our visit, and the gases were prevailingly high in WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 297 carbon dioxide, sulphur dioxide, and sulphur trioxide. Only at the automobile road terminus was chlorine found to be present in an amount sufficient to show appreciably in a field test. Cracks farther removed from the Halemaumau pit show in some cases small amounts of SO,, but more frequently exhale merely steam. Thus in caves where stalactites are forming at a temperature of about 40°,! the gas present was in all cases examined merely air and steam and contained no more CO, than is normally contained in the air. The formation of the stalactites in this cave is accompanied by the formation of gelatinous silica in the presence of some kind of green alge. As might be expected, neither carbon monoxide nor hydrogen was detected in the gases taken from these cracks. SUBLIMATION AND DECOMPOSITION PRODUCTS. Numerous samples of decomposed lava were taken from various points around the crater where the alteration of the surface lava is conspicuous. While the examination of these is not complete, the preliminary results can be summed up by saying that the samples consist primarily of the products to be expected from a sulphuric acid decomposition of the usual basic lava. In most of the places where these samples were gathered the surface is constantly bathed by the volcanic cloud carrying SO,, SO,, and free sulphur, together with steam; which ingredient predominates is of no particular in- terest, so far as the general problem of surface alteration is concerned. In addition to the gaseous products, the breaking down of the lava results in ferric sulphate, which is formed more or less rapidly from the oxide in presence of steam. Alum occurs at favorable places over most of the main floor of the Kilauea Crater, but the amount is rela- tively small. Gypsum is perhaps the most common decomposition product which is left, and this occurs all over the crater. Projecting lava points on the under side of a lava block will often be found tipped with small crystals of gypsum. Since the gases collected point uniformly to the conclusion that the amount of chlorine given off by the crater at the time of our studies was relatively insignificant, it seemed worth while to look for it, as Brun had done, in the older lava which had been exposed to the fumes of the crater for several years. A specimen of lava was ac- cordingly taken on the lee side of the crater rim, where it had been fumed with the gases carried over it by the trade winds for 20 years or more. This lava in a 2-gram sample yielded no test for chlorine. This result is not as satisfactory as it might otherwise be from the fact that the major portion of the exhalation of the volcano is SO., 1W. T. Brigham: ‘‘ The volcanoes of Kilauea and Mauna Loa on the Island of Hawaii,” p. 29. Honolulu, 1909. 298 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. which, when combined with water, readily changes to sulphuric acid and would tend to drive the chlorine out of any combinations which it might form. It constitutes, nevertheless, a plain indication that the amount of chlorine actually evolved is insignificant. DISCUSSION OF RESULTS. GENERAL CONCLUSIONS, In so far, then, as this reconnaissance yields final results, it shows that the gases evolved from the hot lava at the Halemaumau Crater are N,, H,O, CO,, CO, SO,, free H, and free S, with Cl, F, and per- haps NH,, in comparatively insignificant quantity. No argon or other rare gases and no hydrocarbons were found. THE EFFECT OF THE REACTIONS BETWEEN THE GASES. The first plain conclusion which follows from the discovery of this particular group of gases associated together at a temperature of 1,000° or more is that they can not possibly be in equilibrium there, and that chemical action between them is still going on. Whatever may have been the previous opportunities for chemical readjustment among the gases as they rose in solution with the magma and were gradually set free with the diminishing pressure, they are still in process of active reaction when discharged into the air. Free sul- phur, for example, could not have remained in permanently stable association with CO,; neither could free hydrogen be found in stable association with CO, and SO, at 1,000°. THE EFFECT OF THE EXPANSION OF THE GASES. Moreover, as the pressure continued to diminish during the progress of the upward movement, the quantity of gas released from solution, and therefore free to enter into new relations, must have been con- stantly and rapidly increasing up to the moment of discharge into the air. Two consequences follow from the continuation of this operation, which are thermally opposite in sense. First is the rapid expansion of the gases with the release of pressure, which is a cooling phenome- non, and which, if the expansion takes place suddenly from a high pressure into the air, might finally be extremely rapid. AN EXPLANATION OF THE FORMATION OF AA LAVA. Parenthetically, it may be noted in passing that such rapid expan- sion and consequent cooling when occurring suddenly at the surface may very well be the sufficient cause of the Aa lava formations. Great blocks appear to have cooled in this way so rapidly that no op- portunity was given for the suddenly projected and rapidly ex- panding lava outbursts to “ heal” and resume liquid flow. The pro- WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 9399 jected masses are cooled almost instantly throughout their mass and remain discrete blocks of the roughest and most ragged outline (pl. 9), which are pushed forward thereafter in a manner which has been Hiatied to a “moving stone wall,” beneath which the advancing liquid can rarely be seen. This hypothesis of the manner of forma- tion of Aa lava has encountered no limitation from a field examina- tion of Aa flows at the point of outbreak, and enjoys still further confidence from the fact that this is almost the only conceivable method of bringing about a nearly instant cooling throughout the mass of a very large block of lava. (Aa blocks are sometimes re- ported to reach the size of a small house.) Any manner of cooling from the outside inward in such masses must have resulted in much mechanical deformation during the forward movement after the surface had “set,” causing rupture and outbursts of imprisoned liquid, none of which were found in the field. The rate of cooling of gases expanding adiabatically has been espe- cially emphasized 3 Daly,’ who has contended that when the liquid lava finds exit through a long and rather narrow pipe, like the vent at Halernaumau, the pressure must diminish rapidly as the lava rises, and the temperature must fall rapidly in accordance with the law of adiabatic expansion. In order to maintain such an exposed surface basin in the liquid state, it is then necessary to postulate a very high temperature for the lava far below the surface,’ but this has serious difficulties because of the chemical complications which would follow from it. CHEMICAL REACTION BETWEEN THE GASES. The second consequence of the gradual release of gases is the in- terreaction between the gases thus set free in constantly increasing quantity as the surface is approached. These reactions are accom- panied by evolution of heat, which obviously operates to raise the temperature of the surrounding lava so long as the reacting gases remain in contact with it. The heat generated by these gas reactions, in the region near the surface where the amount of gas is large, may well be much more than sufficient to counteract the cooling effect of the expansion within the rising lava column, which may thus become hotter and not cooler as it approaches the surface. Precise figures can hardly be given for the difference in magnitude between the two forces which have been assumed to oppose each other 1For other explanations of the formation of the Aa lava see Green, loc. cit., p. 171; Hitchcock: ‘‘ Hawaii and its voleanoes,” p. 282. Dana: “ Characteristics of volcanoes,” p. 241. R. A. Daly: “ The nature of volcanic action.” Proc. Amer. Acad. Sci., vol. 47, 1911, p. 84, *Daly has calculated a temperature gradient of 2,000° per 37 meters of depth for the rate of cooling of the gas alone, but the calculation takes no account of the relatively enormous mass of adjacent lava which must be cooled by the gas. 300 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. here, the adiabatic cooling on the one hand and the heat of reaction between the gases on the other, for we do not yet know what all the reactions are in such a complicated chemical system, nor do we pos- sess any knowledge of the height of the lava column through which the gases are free to react. In fact, if the tube which feeds the vol- cano from below be supposed to contain both ascending and descend- ing columns of liquid lava of widely variable temperature (Daly) in which the circulation is primarily controlled by the (relatively very large) differences of specific gravity, then it is indeed question- able whether the common equations for adiabatic expansion find ap- plication here at all. In any event, if we may assume such reactions to be going on between the gases as: H, + CO, = CO + H,O + 10,000 calories (Haber) or CO + 4 0, = CO, + 68,000 calories (Haber) or the reaction between gas and lava: 38FeO + HO = Fe,O, + H, + 15,400 calories (Chamberlin) then the effect of adiabatic cooling is certainly of negligible magni- tude in comparison with these. This is reasoning far beyond the data now in hand, but it serves to show that there is no cooling effect of comparable magnitude with the heating effect of the reac- tions going on within the active lava. Tf the reactions quoted above afford a proper measure of the order of magnitude of the heat quantity thus released by chemical reaction within the tube and surface basin of the volcano, we have here hap- pened on an enormous store of volcanic energy which reaches its maximum temperature at the surface itself. It is by no means cer- tain at the moment that this discovery throws any new light on conditions far below the surface, except perhaps to relieve us of the necessity of postulating extreme temperatures for the Java chambers below, which on other grounds must be considered highly improbable.* 1 Whether these gas reactions may serve as a source of heat through which to point the resemblance between volcanic phenomena and geyser action (Daly) must be assigned rather to the realm of geologic speculation. At all events, the superficial phenomena at Kilauea would seem to find a serviceable explanation without requiring any of the ejecta except the gases to be of deep-seated origin. Indeed, the outbreak in May, 1912, of a lava stream from the talus immediately adjacent to the lava lake and some 40 feet above its level (pl. 10) would seem to necessitate differences of pressure, and therefore separate lava chambers, but short distances below the surface, in much the same ther- modynamic relations as those supposed to exist between neighboring geysers of different height and character. Hot gases from a common source percolating through chambers, such as appear to honeycomb the Island of Hawaii, and reacting exothermally through- out their journey as actively as a Bunsen burner, would appear to offer sufficient amount and variety of power to accomplish all the visible activity now seen there. NRUINRUID[R]T JO ISOMUJIOU S19}0UT QNG NOGY “(SL6L ‘So ANN) YSLVYD VANVIIYM JO YOOT4 NIVIN SHL NO VAY ‘piaydaus pure eg—¢16| ‘HWoday ueiuosyyiws "6 S31V1d WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 301] VARIATIONS IN THE COMPOSITION OF THE GASES. Tn full accord with the positive conclusion that these particular gases can not exist togetherinstable equilibrium at the temperature at which they are found, but are in process of active reaction, the record of the analyses shows their composition to vary from one tube to another. Successive tubes collected from the volcano at the same time (Table 2, p. 289) do not show the individual gases to be present in the same proportions, but rather in proportions which change with every bubble which bursts from the liquid basin. VARIATIONS OF LAVA TEMPERATURE RESULTING FROM THE GAS REACTIONS. Further confirmation of the same conclusion is found in the observa- tion, already noted elsewhere, that when the gases given off by the lava increase in quantity (pl. 11), the quantity of lava (lava level in the basin) remaining the same, its temperature increases, and, con- versely, when less gas is discharged through the lava this temperature diminishes again. During the period of our visit in 1912 this change in the temperature at the surface of the active lava in the basin amounted in maximum to 115° (June 13, 1912, 1,070°; July 6, 1912, 1,185°), and is therefore much greater than could be explained in so large a basin by fortuitous conditions of measurement. This absence of equilibrium and consequent variability of composition is also in accord with the observation of Perret and others at Vesuvius, that the relative proportions of the gases vary greatly with the condition of the crater. EXPLOSIVE LAVAS (BRUN). From the same viewpoint the laboratory observations of Brun on “live” or “explosive ” lavas and, in contradistinction, “dead” lavas acquire new and rational significance. In all the experience of the Geophysical Laboratory with the thermal study of silicates, we have found no natural rocks or minerals which did not set free gases in considerable quantity when heated in the laboratory to a temper- ature high enough to melt their chief constituents. Chamberlin,' in his elaborate series of analyses of the gases contained in rocks, seems to have had the same experience. If these studies together represent sufficient breadth of experience to justify a sweeping conclusion, then there are no “dead” rocks, meaning thereby igneous rocks, which no longer release original volatile ingredients when heated to melting. On the other hand, if we admit the nearly or quite universal distribu- tion of gaseous ingredients in igneous rocks, but suppose these gases were in equilibrium with each other throughout the solidification 1R. T. Chamberlin: The gases in rocks, Publications of the Carnegie Institution of Washington, No, 106, 302 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. period, then reheating in the laboratory could discover no “ explo- sive” rocks. The distinction “dead” rocks and “live” or “ explo- sive” rocks loses all significance so long as it applies merely to rocks containing gases in virtual equilibrium with each other, which merely release the gas when heated. But immediately we understand that in lavas carrying gases in solution or mechanical imprisonment the gases shut up therein may react together, with release of heat, the moment they are free to do so, “explosive” lava has a definite mean- ing, and Brun’s experience (loc. cit., p. 55), that “ once the expansion has commenced nothing [for example, withdrawal of the source of heat] can stop it,” becomes a most illuminating one. Rapid expan- sion of the reacting gases, together with the weakening of the inclos- — ing walls through the accession of heat thussuppled from within may very well produce explosive phenomena, in the sense in which Brun used the term, either in nature or in the laboratory. It is otherwise somewhat difficult to see how simple adiabatic expansion of a gas in- closed in walls of obsidian, which are very viscous even at very high temperatures, can produce “explosions” in the manner postulated by Brun. WATER AND THE BASIC MINERALS. There is another conclusion which has been freely offered by those who hold to the view that H,O can not be present as such in the emanations from active volcanoes, of which a statement may be found in the quotation from Green in the opening paragraph of this paper. It states that “the basic minerals themselves give no indica- tions, in the main eruptions, of having been in contact with water, highly susceptible as they are to such an influence.” It appears reasonably certain that the italicized portion of this quotation (italics are ours) is dictated by the relation between basic rock, liquid water, and air at comparatively low temperatures, and to this extent it may very well be true. In the active volcano Kilauea, however, we are dealing with gaseous H,O at a temperature above 1,000°; this is quite another matter. It is a part of our program to endeavor to supply the lack of proper data about the relation between the several gases found and the chief ingredients of the liquid lava, and in view of the absence of such data at the present moment the question raised can receive no very complete answer. It is, neverthe- less, a comparatively simple matter to bring the powdered lava and water together at 1,100° in the absence of oxygen. The result ap- pears to support our view, for after several hours of the most in- timate contact between the gaseous H,O and the lava no chemical change whatever could be detected either in the “basic minerals ~ or the water. In so far as a qualitative experiment of this kind may (Bp 9a1q} LOJ MOF 0} panurjUod apBoswo SI, “Io, ey) 01 II UTOI SUIMOY SUIBOI]S BABL 84} 910 “YS INL “UWoXk} svar oInqord sty} etoyaq sUSTIOU Aaj BIN UISBq BY} JO apts JsaMYqIOU 9Y} UO afd sue? ] } WOdJ SIN OIA opR B JUIMOYS “(SL6OL ‘SS AVIN) JNV7 VAV7] SHL JO MSIA ‘OL atvid "piaydays pue Aeqg—'e16| ‘Hodey uerjuosy}iws “TISB OY} UIYITM MOG JO SUOTJIAITP JUOIOYIP OY} OJON “J]OS}T BAB] OY} JO ISI] yy Aq 4YSTU 4B UHR SBM OANJoId SINT, “(SLEOL ‘8 AINL) ALIALLOW WOWIXV|A] 3O GOIYSd SNIYNG 3XV7 VAY] 4O MalA “LL aLW1d ‘piaudays pue Aeg—'e|6| ‘Hoday ueiuosyyiws WATER AND VOLCANIC ACTIVITY—DAY AND SHEPHERD. 303 be regarded as conclusive, this lava is not appreciably affected by water at the temperatures which obtain in the lava lake up to the time when the water leaves the lava and is discharged into the air. Pending the acquisition of more detailed data, therefore, we may leave this question in abeyance, with reasonable confidence that it will be found to be in full accord with the fact otherwise established, that water is present and participates actively in the volcanic activity at Kilauea. ORIGIN OF THE WATER. If we now grant that water is present as an active ingredient of the - liquid lava, in view of the positive character of the evidence offered, then it becomes pertinent to inquire whether this water is of mag- matic or of meteoric origin. Obviously, to this question no such positive answer can be returned as that which was offered in support of the main thesis of this paper. It is conceivable (1) that water may have entered by infiltration of sea water from the surrounding ocean, or (2) through more or less deep-seated infiltration of water originally meteoric, or, finally, (8) that it may be considered strictly magmatic in character and an original constituent of the lava. The volcanoes of Hawaii are completely surrounded at no great distance by the sea, which rises on their flanks to a height of 15,000 or 16,000 feet, according to charted soundings and the observations of Dutton.t. The crater of Kilauea is about 15 miles from the nearest approach of sea water, as recorded by the most modern surveys. The rock is for the most part porous in high degree. Above sea level rain falls almost daily on the island up to elevations of 7,000 or 8,000 feet. Most of this meteoric water is deposited on the windward side? of the mountains and the leeward portions are desert or nearly so. The Kilauea Crater is situated on the flank of Mauna Loa at an elevation of about 4,000 feet above the sea and is exactly on the ridge which separates the region of rainfall from the desert of Kau. It is some- what misleading to assume with Dana that the rainfall at the crater is comparable with the rainfall at Hilo, the nearest considerable town where meteorologic observations are made. Hilo is to wind- ward of the crater and at sea level. At the Volcano House, still some 3 miles to windward of Halemaumau, the rainfall tables lately published by the United States Geological Survey give the annual average for the years 1909-1911 as 78.7 inches at the Volcano House and 136.5 inches at Hilo. It is also true, though it can not yet be 1C,. E. Dutton: Hawaiian voleanoes. Fourth annual report United States Geological Survey, 1882-83. 2Tt will, of course, be recalled that the islands of the Hawaiian group are within the trade-wind belt, and that the direction of the wind is very nearly constant throughout most of the year, a, 304 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913, supported by measured data, that the rainfall at Halemaumau is even smaller than that recorded at the Volcano House, for at an equal distance to leeward of Halemaumau the country is desert and prac- tically without rainfall. The present crater les in the midst of this transition zone from 78 inches to zero. Be that as it may, there is a more or less abundant rainfall at Kilauea, even though the aggre- gate amount is much smaller than has hitherto been supposed. There is a further fact of observation which may be cited in this connection. Wells have been bored on the sugar plantations at ele- vations up to 2,000 feet on Hawaii and on the other islands. In these borings water is invariably met with (so far as we were able to learn) at sea level only. The water is ordinarily fresh, but a heavy draft on it always has the effect of increasing its salt content, and some of the wells have been permanently ruined for irrigation purposes by this means. So far as the conditions surrounding this voleano are concerned, therefore, water in some form would seem to be very widely dis- tributed except on the high mountains, and as freely available as silica for active participation in any form of volcanic activity. In the present preliminary survey of the situation it therefore appears as if any attempt to assign the water found in the lava to one or other of these three conceivable sources, or, perhaps better, to justify any specific distribution of it among the three conceivable sources, must be based on assumptions of a somewhat arbitrary and hypothetical character. Nevertheless, there are some indications which inevitably give direction to the probabilities which an individual observer may fix on. First and most important, in our opinion, is the fact that the nitrogen found in the emanation is free from argon. It is plain that if atmospheric water is to reach a hot lava column at a tem- perature of 1,000° or higher it must do so as a gas, and therefore on the same terms as other atmospheric gases. Argon is invariably contained in the air in measurable quantity and forms no chemieal compounds. Whence it follows that if the gases of the atmosphere had reached the liquid lava in any manner whatsoever the argon would be released with the others, but no trace of argon was found. The second difficulty is to conceive a mechanism whereby atmos- pheric or surface water of whatever origin (for example, the sea) can make its way into a lava column or basin at a temperature of 1,000° or more. The Daubrée experiment, whereby water vapor was found to make its way through 2 centimeters of sandstone against an excess pressure within, though often quoted in this connection, does not help us to a solution of it. The force which was active in —~ WATER AND VOLCANIC ACTIVITY——-DAY AND SHEPHERD. 305 Daubrée’s experiment is the surface tension of water only,' and water will obviously have no surface tension above its critical temperature of 374° (except perhaps in so far as salts in solution may have the effect of raising this critical temperature slightly). This tempera- ture passed, water must make its way precisely like any other gas by diffusion through pores or by overcoming whatever chemical or mechanical conditions it may encounter. The prospect is not an encouraging one. The hydrostatic pressure at great depths of the sea would appear to be the only sufficiently powerful agent to drive water against a high adverse temperature gradient, but to invoke this would be to invite nice distinctions of where “ magmatic” water begins and “meteoric” water ends. The presence or absence of chlorine is not a conclusive factor one way or the other, because the physical processes of infiltration through porous rock and of distil- lation are alike of such a kind as gradually to leave the dissolved salts behind; this is illustrated by the fact that the bore holes yield fresh water except when the infiltration is very rapid. To us, therefore, such evidence as there is appears to indicate that the water released from the liquid lava when it reaches the surface is entitled to be considered an original component of the lava with as much right as the sulphur or the carbon. 1“ Capillary forces are effective only when there is a surface of separation within the pores. * * * Since the pressure discontinuity occurs only at the surface of separa- tion, a column of liquid can be supported only when there is a free liquid surface within thevcapillary. * | * * “* « * As regards the influence of temperature on the surface tension of water, all the investigations unite in showing that its surface tension decreases regularly with rise of temperature, becoming zero, of course, at the critical temperature where there is no surface of separation. The relation is practically linear when the whole range is con- sidered ; it may be represented with sufficient accuracy by the formula, ¢ t==78 — 0.21 ¢ or 0.21 (370—7) where ¢¢ is the surface tension at ¢° (temperature centigrade) expressed in dynes per centimeter. “*« * * From this * * +* it is evident that the pressure producible by capil- larity is insignificant in comparison with the hydrostatic pressure, except for very fine pores * * * and this minuteness of the pores leads us to inquire what amount of water could actually flow through them. * * * Assuming the mean viscosity of the water to be 0.005 (its value at a temperature of 30°), the amount of water flowing through a pore of diameter 1 y# ji. e., 1/25,000 inch) would be about 15 x 10-6 ce, per year. * * * Now, if we make the very generous estimate that 10 per cent of the volume occupied by the rock consists of pore spaces * * * the quantity of water flowing would be only 15 cc. per sq. cm. of surface per year. * * * Jf the diameter of the pores is 0.01 » the amount of water flowing would be 0.0015 cc. per sq. cm. of surface per year. * * * In other words, a period of 1,000 years would be required for a quantity of water equivalent to 1.5 cms. (about one-half inch) of rain to flow past a given horizontal plane. “* * * It appears, therefore, as if the probabilities were all against the notion that appreciable amounts of meteoric water can ever penetrate into deep-seated and highly heated rock masses.” (John Johnston and L. H. Adams: “ Observations on the Daubrée experiment and capillarity in relation to certain geologic speculations.” Journal of Geology, vol. 22, in press, 1913.) 44863°—sm 1918——20 Phat ot diaeE Now uiiaviniiarariod att 9d ot saree aa < c Aaese re rites MES YK; BW: eri Sa tie) om cutee oie Arms § ‘ .F a Nesta’ ae Fonte siege a. “aa pede pire brs ae + inna 93. agi: Mon ib ody. rid evaqginr: 4, genre ded. 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