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Full text of "Year book - Carnegie Institution of Washington"

Digitized by the Internet Archive 

in 2012 with funding from 

LYRASIS Members and Sloan Foundation 



http://www.archive.org/details/yearbookcarne41194142carn 



CARNEGIE INSTITUTION 
OF WASHINGTON 



YEAR BOOK No. 41 
July 1, 1941- June 30, 1942 

With Administrative Reports through December 18, 1942 




CARNEGIE INSTITUTION OF WASHINGTON 
WASHINGTON, D. C. 

1942 



THE LORD BALTIMORE PRESS, BALTIMORE, MARYLAND 



CONTENTS 

PAGES 

Officers and Staff v-x 

Organization, Plan, and Scope xi 

Articles of Incorporation xii-xiv 

By-Laws of the Institution xv-xviii 

Abstract of Minutes of the Forty-fourth Meeting of the Board of Trustees xix-xx 

Report of the Executive Committee xxi— xxv 

Report of Auditors xxvi-xxxii 

Report of the President i—g 

Reports of Departmental Activities and Cooperative Studies 
Astronomy 

Mount Wilson Observatory , 1-24 

Special Projects 

Dirk Brouwer 25 

S. A. Mitchell 26-28 

Terrestrial Sciences 

Geophysical Laboratory 29- 37 

Department of Terrestrial Magnetism 39- 86 

Special Projects 

Committee on Coordination of Cosmic-Ray Investigations 87-102 

Robert B. Brode 90 

A. H. Compton 90- 94 

S. E. Forbush and Isabelle Lange 94 

Victor F. Hess 94- 96 

Thomas H. Johnson 96- 97 

S. A. Korff 97- 99 

Robert A. Millikan 99-102 

Wilson M. Powell 102 

California Institute of Technology 102-106 

University of Pittsburgh 106-107 

Joseph C. Boyce 107-1 1 1 

W. H. Newhouse 11 1-1 12 

Publications in Connection with Other Projects 112 

Biological Sciences 

Division of Plant Biology 1 13-143 

Department of Embryology 145-168 

Department of Genetics . 169-218 

Nutrition Laboratory 219-223 

iii 



CONTENTS 

Special Projects pages 

W. E. Castle 225-226 

Paul S. Conger 226-227 

Th. Dobzhansky 228-234 

Charles Elton 234—235 

Arthur T. Hertig and John Rock 235-237 

Elliott P. Joslin 237 

Charles W. Metz and Martha Lee Bozeman 237-242 

T. H. Morgan and Jack Schultz 242-245 

H. C. Sherman 245-246 

Historical Research 

Division of Historical Research 247-281 

Special Projects 

Marion E. Blake 283 

Paleontology, Early Man, and Historical Geology: John C. Merriam. . . . 284-297 

Bibliography 299-300 

Index 301-309 



IV 



Thomas Barbour 
James F. Bell 
Robert Woods Bliss 
Lindsay Bradford 
Frederic A. Delano 
Homer L. Ferguson 
W. Cameron Forbes 
Walter S. Gifford 



Vannevar Bush 
Frederic A. Delano 



PRESIDENT AND TRUSTEES 

PRESIDENT 

Vannevar Bush 

BOARD OF TRUSTEES 

W. Cameron Forbes, Chairman 

Walter S. Gifford, V ice-Chairman 

Frederic A. Delano, Secretary 

Herbert Hoover Henning W. Prentis, Jr. 

Walter A. Jessup Elihu Root, Jr. 

Frank B. Jewett Henry R. Shepley 

Alfred L. Loomis Richard P. Strong 

Roswell Miller Charles P. Taft 

Henry S. Morgan James W. Wadsworth 

Seeley G. Mudd Frederic C. Walcott 

John J. Pershing Lewis H. Weed 



Executive Committee 

W. Cameron Forbes, Chairman 
Walter S. Gifford 
Walter A. Jessup 



Frederic C. Walcott 
Lewis H. Weed 



Henry R. Shepley 



Finance Committee 

Frederic C. Walcott, Chairman 
Lindsay Bradford Frank B. Jewett 

Walter S. Gifford Elihu Root, Jr. 

Auditing Committee 

Frederic A. Delano, Chairman 
Robert Woods Bliss James W. Wadsworth 

STANDING COMMITTEES FOR THE YEAR 1943 

Committee on Astronomy 

Herbert Hoover, Chairman 



Walter S. Gifford 
Roswell Miller 



Seeley G. Mudd 
Elihu Root, Jr. 



Committee on Terrestrial Sciences 

Frank B. Jewett, Chairman 
Frederic A. Delano Henry S. Morgan 

Homer L. Ferguson Frederic C. Walcott 

Committee on Biological Sciences 

Lewis H. Weed, Chairman 
Thomas Barbour Walter A. Jessup 

James F. Bell Alfred L. Loomis 

Committee on Historical Research 

Henry R. Shepley, Chairman 
Robert Woods Bliss Charles P. Taft 

Richard P. Strong James W. Wadsworth 

v 



FORMER PRESIDENTS AND TRUSTEES 



PRESIDENTS 

Daniel Coit Gilman, 1902-04 Robert Simpson Woodward, 1904-20 

John Campbell Merriam, President 1921-38; President Emeritus 1939- 



Alexander Agassiz 
George J. Baldwin 
John S. Billings 
Robert S. Brookings 
John L. Cadwalader 
William W. Campbell 
John J. Carty 
Whitefoord R. Cole 
Cleveland H. Dodge 
William E. Dodge 
Charles P. Fenner 
Simon Flexner 
William N. Frew 
Lyman J. Gage 
Cass Gilbert 
Frederick H. Gillett 
Daniel C. Gilman 
John Hay 
Myron T. Herrick 
Abram S. Hewitt 
Henry L. Higginson 
Ethan A. Hitchcock 
Henry Hitchcock 
William Wirt Howe 
Charles L. Hutchinson 
Samuel P. Langley 
Charles A. Lindbergh 
William Lindsay 
Henry Cabot Lodge 
Seth Low 



TRUSTEES 




1904-05 


Wayne MacVeagh 


1902—07 


1925-27 


Andrew J. Mellon 


!9 2 4-37 


1902-13 


Darius O. Mills 


1902-09 


1910-29 


S. Weir Mitchell 


1902—14 


1903-14 


Andrew J. Montague 


1907-35 


1929-38 


William W. Morrow 


1902—29 


1916-32 


William Church Osborn 


1 9 2 7-34 


1925-34 


James Parmelee 


I 9 1 7~3 1 


1903-23 


Wm. Barclay Parsons 


1907-32 


1902-03 


Stewart Paton 


1916-42 


1914-24 


George W. Pepper 


1914-19 


1910-14 


Henry S. Pritchett 


1906-36 


1902-15 


Elihu Root 


1902-37 


1902-12 


Julius Rosenwald 


1929-31 


1924-34 


Martin A. Ryerson 


1908-28 


!9 2 4-35 


Theobald Smith 


1914-34 


1902-08 


John C. Spooner 


1902-07 


1902-05 


William Benson Storey 


1924-39 


1915-29 


William H. Taft 


1906-15 


1902-03 


William S. Thayer 


1929-32 


1902-19 


Charles D. Walcott 


1902-27 


1902-09 


Henry P. Walcott 


1910-24 


1902-02 


William H. Welch 


1906-34 


1903-09 


Andrew D. White 


1902-03 


1902—04 


Edward D. White 


1902-03 


1904-06 


Henry White 


1913-27 


1 934-39 


George W. Wickersham 


1909-36 


1902-09 


Robert S. Woodward 


1905-24 


1914-24 


Carroll D. Wright 


1902—08 


1902-16 







Besides the names enumerated above, the following were ex-officio members of the Board 
of Trustees under the original charter, from the date of organization until April 28, 1904: 
the President of the United States, the President of the Senate, the Speaker of the House 
of Representatives, the Secretary of the Smithsonian Institution, the President of the 
National Academy of Sciences. 



VI 



STAFF OF INVESTIGATORS FOR THE YEAR 1942 



ASTRONOMY 



Mount Wilson Observatory 
Organized in 1904; George E. Hale, Director 1904-1923, Honorary Director 1923-1936 



Walter S. Adams, Director 

Alfred H. Joy, Secretary 

Arthur S. King, Sitpt. Physical Laboratory 

John A. Anderson 

Walter Baade 

Harold D. Babcock 

William H. Christie 

Theodore Dunham, Jr. 

Joseph Hickox 

Edison Hoge 

Edwin P. Hubble 

Milton L. Humason 



Robert B. King 
Paul W. Merrill 
Rudolph Minkowski 
Seth B. Nicholson 
Edison Pettit 
Robert S. Richardson 
Roscoe F. Sanford 
gustaf stromberg 
Adriaan van Maanen 
Olin C. Wilson 
Ralph E. Wilson 



TERRESTRIAL SCIENCES 



Geophysical Laboratory 
Organized in 1906, opened in 1907; Arthur L. Day, Director 1907-1936 



L. H. Adams, Director 

J. S. Burlew 

Allen Crocker (resigned) 

J. L. England 

R. E. Gibson 

R. W. Goranson 

J. W. Greig 

Earl Ingerson 

F. C. Kracek 

O. H. Loeffler 

H. E. Merwin 



G. W. Morey 
E. F. Osborn 
C. S. Piggot 
Eugene Posnjak 
H. S. Roberts 
J. F. Schairer 

E. S. Shepherd 
George Tunell 
W. D. Urry 

F. E. Wright 
E. G. Zies 



Department of Terrestrial Magnetism 

Organized in 1904; L. A. Bauer, Director 1 904-1929 



J. A. Fleming, Director 

O. H. Gish, Assistant Director 

P. H. Abelson 

C. J. Aronson 

L. V. Berkner 

R. C. Coile (resigned) 

S. E. Forbush 

G. K. Green 

L. R. Hafstad 

N. P. Heydenburg 

E. A. Johnson 

H. F. Johnston 

M. W. Jones 

P. G. Ledig 



A. G. McNish 
R. C Meyer 
W. C. Parkinson 
R. B. Roberts 
W. J. Rooney 
W. E. Scott 
S. L. Seaton 
K. L. Sherman 
W. F. Steiner 
O. W. Torreson 
M. A. Tuve 
E. H. Vestine 
G. R. Wait 
H. W. Wells 



vu 



BIOLOGICAL SCIENCES 
Division of Plant Biology 

Desert Laboratory, opened in 1903, became headquarters of Department of Botanical Research in 1905. 
Name changed to Laboratory for Plant Physiology in 1923; reorganized in 1928 as Division of Plant 
Biology, including Ecology. 

H. A. Spoehr, Chairman Emmett V. Martin 

Jens Clausen H. W. Milner 

William M. Hiesey Forrest Shreve 

David D. Keck James H. C. Smith 

Winston M. Manning Harold H. Strain 

Department of Embryology 
Organized in 1914; Franklin P. Mall, Director 1914-1917; George L. Streeter, Director 1918-1940 

George W. Corner, Director Chester H. Heuser, Curator of the Embryo- 

Robert K. Burns, Jr. logical Collection 

Louis B. Flexner Margaret R. Lewis 

Alfred Gellhorn, Fellow Samuel R. M. Reynolds 

Department of Genetics 

Station for Experimental Evolution, opened in 1904, combined with Eugenics Record Office in 1921 to 
form Department of Genetics. Charles B. Davenport, Director 1904-1934; A. F. Blakeslee, Director 
1935-1941. 

M. Demerec, Acting Director James S. Potter 

Amos G. Avery Oscar Riddle 

A. Dorothy Bergner Sophia Satina 
Ugo Fano, Fellow Morris Steggerda 

B. P. Kaufmann H. E. Warmke 
E. C. MacDowell 

Nutrition Laboratory 

Organized in 1907, opened in 1908; F. G. Benedict, Director 1 907-1 937 

T. M. Carpenter, Acting Director Robert C. Lee 

V. Coropatchinsky 

HISTORICAL RESEARCH 

Division of Historical Research 

Department of Historical Research organized in 1903; Andrew C. McLaughlin, Director 1903-1905, 
J. Franklin Jameson, Director 1905— 1928. In 1930 this Department was incorporated as the Section of 
United States History in a new Division of Historical Research. 

A. V. Kidder, Chairman 
Section of Aboriginal American History Section of Post-Columbian American History 

Sylvanus G. Morley Eleanor B. Adams 

Earl H. Morris Robert S. Chamberlain 

H. E. D. Pollock Ralph L. Roys 

Karl Ruppert France V. Scholes 

Anna O. Shepard Leo F. Stock 

Edwin M. Shook 

A. Ledyard Smith Section of the History of Science 

Robert E. Smith Georgf Won 

Gustav Stromsvik Alexander Pogo 

Sol Iax 

J. Eric S. Thompson 

Alfonso Villa R. 

viii 



RESEARCH ASSOCIATES 

Marion E. Blake, Archaeology Frank A. Perret, Geophysics 

Paul S. Conger, Biology John T. Tate, Physics 

Newton B. Drury, Study of Primitive Areas 

Research Associates Engaged in Post-Retirement Studies 

A. F. Blakeslee, Genetics George L. Streeter, Embryology 

Frederick H. Seares, Astronomy 

Research Associates Connected with Other Institutions 

Ernest B. Babcock (University of California), Genetics 

V. Bjerknes (University of Oslo), Meteorology 

Edward L. Bowles (Massachusetts Institute of Technology), Physics 

Joseph C. Boyce (Massachusetts Institute of Technology), Physics 

E. H. Bramhall (University of Alaska), Terrestrial Magnetism 

G. Breit (University of Wisconsin), Physics 

Robert B. Brode (University of California), Physics 

Dirk Brouwer (Yale University), Astronomy 

John P. Buwalda (California Institute of Technology), Geology and Paleontology 

W. E. Castle (University of California), Biology 

Ralph W. Chaney (University of California), Paleobotany 

A. H. Compton (University of Chicago), Physics 

L. S. Cressman (University of Oregon), Archaeology 

Th. Dobzhansky (Columbia University), Genetics 

Charles Elton (Oxford University), Climatology 

G. Gamow (George Washington University), Physics 

Frank T. Gucker, Jr. (Northwestern University), Chemistry 

Ross Gunn (United States Naval Research Laboratory), Terrestrial Magnetism 

Arthur T. Hertig (Boston Lying-in Hospital), Embryology 

H. H. Hess (Princeton University), Geophysics 

Victor F. Hess (Fordham University), Physics 

A. Hollaender (National Institute of Health), Genetics 

Edgar B. Howard (University of Pennsylvania), Archaeology and Paleontology 

James H. Jeans (Royal Society of London), Astronomy 

Einar Jensen (University of Oslo), Geophysics 

Thomas H. Johnson (Bartol Research Foundation), Physics 

Elliott P. Joslin (New England Deaconess Hospital), Nutrition 

Remington Kellogg (United States National Museum), Paleontology 

S. A. Korff (Bartol Research Foundation), Physics 

E. A. Lowe (The Institute for Advanced Study), Paleography 

Edwin D. McKee (United States National Park Service), Geology and Paleontology 

Charles W. Metz (University of Pennsylvania), Biology 

Robert A. Millikan (California Institute of Technology), Physics 

S. A. Mitchell (University of Virginia), Astronomy 

T. H. Morgan (California Institute of Technology), Biology 

Walter H. Newhouse (Massachusetts Institute of Technology), Geophysics 

Wilson M. Powell (University of California), Physics 

Robert Redfield (University of Chicago), Anthropology 

Henry N. Russell (Princeton University), Astronomy 

H. C. Sherman (Columbia University), Nutrition 

Alexander Silverman (University of Pittsburgh), Geophysics 

Joel Stebbins (University of Wisconsin), Astronomy 

Chester Stock (California Institute of Technology), Paleontology 

ix 



OFFICES OF ADMINISTRATION 



Office of the President 

Vannevar Bush, President 

Walter M. Gilbert, Executive Officer 

Samuel Callaway, President's Secretary 



Office of Publications and Public Relations 

Theodore H. Dillon, Director 
Dorothy R. Swift, Editor 



Office of the Bursar 

Earle B. Biesecker, Bursar 

J. Stanley Lingebach, Assistant Bursar 



Investment Office {New Yor\ City) 

Devereux Josephs, Investment Officer 
Parker Monroe, Investment Officer 



ORGANIZATION, PLAN, AND SCOPE 

The Carnegie Institution of Washington was founded by Andrew Carnegie, 
January 28, 1902, when he gave to a board of trustees an endowment of registered 
bonds of the par value of ten million dollars. To this fund an addition of two 
million dollars was made by Mr. Carnegie on December 10, 1907, and a further 
addition of ten million dollars was made by him on January 19, 1911. Further- 
more, the income of a reserve fund of about three million dollars, accumulated 
in accordance with the founder's specifications in 191 1, is now available for general 
use and a sum of five million dollars has been paid by the Carnegie Corporation 
of New York as an increase to the Endowment Fund of the Institution, payments 
having been completed in 1931. The Institution was originally organized under 
the laws of the District of Columbia and incorporated as the Carnegie Institution, 
articles of incorporation having been executed on January 4, 1902. The Institu- 
tion was reincorporated, however, by an act of the Congress of the United States, 
approved April 28, 1904, under the title of the Carnegie Institution of Washington. 
(See existing Articles of Incorporation on following pages.) 

Organization under the new Articles of Incorporation was effected May 18, 1904, 
and the Institution was placed under the control of a board of twenty-four trustees, 
all of whom had been members of the original corporation. The trustees meet 
annually in December to consider the affairs of the Institution in general, the prog- 
ress of work already undertaken, and the initiation of new projects, and to make 
the necessary appropriations for the ensuing year. During the intervals between 
the meetings of the trustees the affairs of the Institution are conducted by an Execu- 
tive Committee chosen by and from the Board of Trustees and acting through 
the President of the Institution as chief executive officer. 

The Articles of Incorporation of the Institution declare in general "that the 
objects of the corporation shall be to encourage, in the broadest and most liberal 
manner, investigation, research, and discovery, and the application of knowledge 
to the improvement of mankind." 

The Institution is essentially an operating organization. It attempts to advance 
fundamental research in fields not normally covered by the activities of other agen- 
cies, and to concentrate its attention upon specific problems, with the idea of shift- 
ing attack from time to time to meet the more pressing needs of research as they 
develop with increase of knowledge. Some of these problems require the collabora- 
tion of several investigators, special equipment, and continuous effort. Many close 
relations exist among activities of the Institution, and a type of organization repre- 
senting investigations in astronomy, in terrestrial sciences, in biological sciences, 
and in historical research has been effected. Conference groups on various subjects 
have played a part in bringing new vision and new methods to bear upon many 
problems. Constant efforts are made to facilitate interpretation and application of 
results of research activities of the Institution, and an Office of Publications provides 
means for appropriate publication. 

xi 



ARTICLES OF INCORPORATION 

Public No. 260. An Act to incorporate the Carnegie Institution of Washington. 

Be it enacted by the Senate and House of Representatives of the United States of 
America in Congress assembled, That the persons following being persons who are 
now trustees of the Carnegie Institution, namely, Alexander Agassiz, John S. Billings, 
John L. Cadwalader, Cleveland H. Dodge, William N. Frew, Lyman J. Gage, 
Daniel C. Gilman, John Hay, Henry L. Higginson, William Wirt Howe, Charles L. 
Hutchinson, Samuel P. Langley, William Lindsay, Seth Low, Wayne MacVeagh, 
Darius O. Mills, S. Weir Mitchell, William W. Morrow, Ethan A. Hitchcock, 
Elihu Root, John C. Spooner, Andrew D. White, Charles D. Walcott, Carroll D. 
Wright, their associates and successors, duly chosen, are hereby incorporated and 
declared to be a body corporate by the name of the Carnegie Institution of Wash- 
ington and by that name shall be known and have perpetual succession, with the 
powers, limitations, and restrictions herein contained. 

Sec. 2. That the objects of the corporation shall be to encourage, in the broadest 
and most liberal manner, investigation, research, and discovery, and the applica- 
tion of knowledge to the improvement of mankind; and in particular — 

(a) To conduct, endow, and assist investigation in any department of science, 
literature, or art, and to this end to cooperate with governments, universities, col- 
leges, technical schools, learned societies, and individuals. 

(b) To appoint committees of experts to direct special lines of research. 

(c) To publish and distribute documents. 

(d) To conduct lectures, hold meetings, and acquire and maintain a library. 

(e) To purchase such property, real or personal, and construct such building or 
buildings as may be necessary to carry on the work of the corporation. 

(f) In general, to do and perform all things necessary to promote the objects 
of the institution, with full power, however, to the trustees hereinafter appointed 
and their successors from time to time to modify the conditions and regulations 
under which the work shall be carried on, so as to secure the application of the 
funds in the manner best adapted to the conditions of the time, provided that the 
objects of the corporation shall at all times be among the foregoing or kindred thereto. 

Sec. 3. That the direction and management of the affairs of the corporation and 
the control and disposal of its property and funds shall be vested in a board of trus- 
tees, twenty-two in number, to be composed of the following individuals: Alexander 
Agassiz, John S. Billings, John L. Cadwalader, Cleveland H. Dodge, William N. 
Frew, Lyman J. Gage, Daniel C. Gilman, John Hay, Henry L. Higginson, William 
Wirt Howe, Charles L. Hutchinson, Samuel P. Langley, William Lindsay, Seth 
Low, Wayne MacVeagh, Darius O. Mills, S. Weir Mitchell, William W. Morrow, 
Ethan A. Hitchcoc\, Elihu Root, John C. Spooner, Andrew D. White, Charles D. 
Walcott, Carroll D. Wright, who shall constitute the first board of trustees. The 
board of trustees shall have power from time to time to increase its membership 

xii 



ARTICLES OF INCORPORATION 

to not more than twenty-seven members. Vacancies occasioned by death, resigna- 
tion, or otherwise shall be filled by the remaining trustees in such manner as the 
by-laws shall prescribe; and the persons so elected shall thereupon become trustees 
and also members of the said corporation. The principal place of business of the 
said corporation shall be the city of Washington, in the District of Columbia. 

Sec. 4. That such board of trustees shall be entitled to take, hold, and administer 
the securities, funds, and property so transferred by said Andrew Carnegie to the 
trustees of the Carnegie Institution and such other funds or property as may at any 
time be given, devised, or bequeathed to them, or to such corporation, for the pur- 
poses of the trust; and with full power from time to time to adopt a common seal, 
to appoint such officers, members of the board of trustees or otherwise, and such 
employees as may be deemed necessary in carrying on the business of the corpora- 
tion, at such salaries or with such remuneration as they may deem proper; and 
with full power to adopt by-laws from time to time and such rules or regulations 
as may be necessary to secure the safe and convenient transaction of the business of 
the corporation; and with full power and discretion to deal with and expend the 
income of the corporation in such manner as in their judgment will best promote 
the objects herein set forth and in general to have and use all powers and authority 
necessary to promote such objects and carry out the purposes of the donor. The 
said trustees shall have further power from time to time to hold as investments 
the securities hereinafter referred to so transferred by Andrew Carnegie, and any 
property which has been or may be transferred to them or such corporation by 
Andrew Carnegie or by any other person, persons, or corporation, and to invest 
any sums or amounts from time to time in such securities and in such form and 
manner as are permitted to trustees or to charitable or literary corporations for in- 
vestment, according to the laws of the States of New York, Pennsylvania, or Massa- 
chusetts, or in such securities as are authorized for investment by the said deed of 
trust so executed by Andrew Carnegie, or by any deed of gift or last will and testa- 
ment to be hereafter made or executed. 

Sec. 5. That the said corporation may take and hold any additional donations, 
grants, devises, or bequests which may be made in further support of the purposes 
of the said corporation, and may include in the expenses thereof the personal ex- 
penses which the trustees may incur in attending meetings or otherwise in carrying 
out the business of the trust, but the services of the trustees as such shall be gratuitous. 

Sec. 6. That as soon as may be possible after the passage of this Act a meeting 
of the trustees hereinbefore named shall be called by Daniel C. Gilman, John S. 
Billings, Charles D. Walcott, S. Weir Mitchell, John Hay, Elihu Root, and Carroll D. 
Wright, or any four of them, at the city of Washington, in the District of Columbia, 
by notice served in person or by mail addressed to each trustee at his place of resi- 
dence; and the said trustees, or a majority thereof, being assembled, shall organize 
and proceed to adopt by-laws, to elect officers and appoint committees, and generally 
to organize the said corporation; and said trustees herein named, on behalf of the 
corporation hereby incorporated, shall thereupon receive, take over, and enter into 
possession, custody, and management of all property, real or personal, of the cor- 
poration heretofore known as the Carnegie Institution, incorporated, as hereinbefore 
set forth under "An Act to establish a Code of Law for the District of Columbia, 

xiii 



CARNEGIE INSTITUTION OF WASHINGTON 

January fourth, nineteen hundred and two," and to all its rights, contracts, claims, 
and property of any kind or nature; and the several officers of such corporation, or 
any other person having charge of any of the securities, funds, real or personal, 
books, or property thereof, shall, on demand, deliver the same to the said trustees 
appointed by this Act or to the persons appointed by them to receive the same; 
and the trustees of the existing corporation and the trustees herein named shall 
and may take such other steps as shall be necessary to carry out the purposes of 
this Act. 

Sec. 7. That the rights of the creditors of the said existing corporation known as 
the Carnegie Institution shall not in any manner be impaired by the passage of this 
Act, or the transfer of the property hereinbefore mentioned, nor shall any liability 
or obligation for the payment of any sums due or to become due, or any claim 
or demand, in any manner or for any cause existing against the said existing cor- 
poration, be released or impaired; but such corporation hereby incorporated is de- 
clared to succeed to the obligations and liabilities and to be held liable to pay 
and discharge all of the debts, liabilities, and contracts of the said corporation so 
existing to the same effect as if such new corporation had itself incurred the obliga- 
tion or liability to pay such debt or damages, and no such action or proceeding 
before any court or tribunal shall be deemed to have abated or been discontinued 
by reason of the passage of this Act. 

Sec. 8. That Congress may from time to time alter, repeal, or modify this Act 
of incorporation, but no contract or individual right made or acquired shall thereby 
be divested or impaired. 

Sec. 9. That this Act shall take effect immediately. 

Approved, April 28. 1904 ' 



xiv 



BY-LAWS OF THE INSTITUTION 

Adopted December 13, 1904. Amended December 13, 1910, December 13, 1912, 
December 10, 1937, December 15, 1939, December 13, 1940, and December 18, 1942 

Article I 

THE TRUSTEES 

1. The Board of Trustees shall consist of twenty-four members, with power to 
increase its membership to not more than twenty-seven members. The Trustees 
shall hold office continuously and not for a stated term. 

2. In case any Trustee shall fail to attend three successive annual meetings of the 
Board he shall thereupon cease to be a Trustee. 

3. No Trustee shall receive any compensation for his services as such. 

4. All vacancies in the Board of Trustees shall be filled by the Trustees by ballot. 
Sixty days prior to an annual or a special meeting of the Board, the President shall 
notify the Trustees by mail of the vacancies to be filled and each Trustee may sub- 
mit nominations for such vacancies. A list of the persons so nominated, with the 
names of the proposers, shall be mailed to the Trustees thirty days before the meet- 
ing, and no other nominations shall be received at the meeting except with the 
unanimous consent of the Trustees present. Vacancies shall be filled from the 
persons thus nominated, but no person shall be declared elected unless he receives 
the votes of two-thirds of the Trustees present. 

Article II 

MEETINGS 

1. The annual meeting of the Board of Trustees shall be held in the City of 
Washington, in the District of Columbia, on the first Friday following the second 
Thursday of December in each year unless the date and place of meeting are other- 
wise ordered by the Executive Committee. 

2. Special meetings of the Board may be called by the Executive Committee by 
notice served personally upon, or mailed to the usual address of, each Trustee twenty 
days prior to the meeting. 

3. Special meetings shall, moreover, be called in the same manner by the Chairman 
upon the written request of seven members of the Board. 

Article III 

OFFICERS OF THE BOARD 

i. The officers of the Board shall be a Chairman of the Board, a Vice-Chairman, 
and a Secretary, who shall be elected by the Trustees, from the members of the 
Board, by ballot to serve for a term of three years. All vacancies shall be filled by 
the Board for the unexpired term; provided, however, that the Executive Com- 
mittee shall have power to fill a vacancy in the office of Secretary to serve until 
the next meeting of the Board of Trustees. 

2. The Chairman shall preside at all meetings and shall have the usual powers 
of a presiding officer. 

2 xv 



CARNEGIE INSTITUTION OF WASHINGTON 

3. The Vice-Chairman, in the absence or disability of the Chairman, shall perform 
his duties. 

4. The Secretary shall issue notices of meetings of the Board, record its transactions, 
and conduct that part of the correspondence relating to the Board and to his duties. 

Article IV 

EXECUTIVE ADMINISTRATION 

The President 

1. There shall be a President who shall be elected by ballot by, and hold office 
during the pleasure of, the Board, who shall be the chief executive officer of the 
Institution. The President, subject to the control of the Board and the Executive 
Committee, shall have general charge of all matters of administration and super- 
vision of all arrangements for research and other work undertaken by the Institu- 
tion or with its funds. He shall devote his entire time to the affairs of the Insti- 
tution. He shall prepare and submit to the Board of Trustees and to the Executive 
Committee plans and suggestions for the work of the Institution, shall conduct its 
general correspondence and the correspondence with applicants for grants and with 
the special advisers of the Committee, and shall present his recommendations in 
each case to the Executive Committee for decision. All proposals and requests for 
grants shall be referred to the President for consideration and report. He shall have 
power to remove and appoint subordinate employees and shall be ex officio a 
member of the Executive Committee. 

2. He shall be the legal custodian of the seal and of all property of the Institution 
whose custody is not otherwise provided for. He shall sign and execute on behalf 
of the corporation all contracts and instruments necessary in authorized adminis- 
trative and research matters and affix the corporate seal thereto when necessary, 
and may delegate the performance of such acts and other administrative duties in 
his absence to the Executive Officer. He may execute all other contracts, deeds, 
and instruments on behalf of the corporation and affix the seal thereto when ex- 
pressly authorized by the Board of Trustees or Executive Committee. He may, within 
the limits of his own authorization, delegate to the Executive Officer authority to 
act as custodian of and affix the corporate seal. He shall be responsible for the 
expenditure and disbursement of all funds of the Institution in accordance with 
the directions of the Board and of the Executive Committee, and shall keep accurate 
accounts of all receipts and disbursements. He shall submit to the Board of Trustees 
at least one month before its annual meeting in December a written report of the 
operations and business of the Institution for the preceding fiscal year with his 
recommendations for work and appropriations for the succeeding fiscal year, which 
shall be forthwith transmitted to each member of the Board. 

3. He shall attend all meetings of the Board of Trustees. 

4. There shall be an officer designated Executive Officer who shall be appointed by 
and hold office at the pleasure of the President, subject to the approval of the Execu- 
tive Committee. His duties shall be to assist and act for the President as the latter 
may duly authorize and direct. 

xv i 



BY-LAWS OF THE INSTITUTION 

5. The President shall retire from office at the end of the calendar year in which 
he becomes sixty-five years of age. 

Article V 

COMMITTEES 

1. There shall be the following standing Committees, viz. an Executive Committee, 
a Finance Committee, and an Auditing Committee. 

2. The Executive Committee shall consist of the Chairman and Secretary of the 
Board of Trustees and the President of the Institution ex officio and, in addition, 
five trustees to be elected by the Board by ballot for a term of three years, who 
shall be eligible for re-election. Any member elected to fill a vacancy shall serve 
for the remainder of his predecessor's term: Provided, however, that of the Execu- 
tive Committee first elected after the adoption of these by-laws two shall serve for 
one year, two shall serve for two years, and one shall serve for three years; and such 
Committee shall determine their respective terms by lot. 

3. The Executive Committee shall, when the Board is not in session and has 
not given specific directions, have general control of the administration of the affairs 
of the corporation and general supervision of all arrangements for administration, 
research, and other matters undertaken or promoted by the Institution; shall ap- 
point advisory committees for specific duties; shall determine all payments and 
salaries; and keep a written record of all transactions and expenditures and submit 
the same to the Board of Trustees at each meeting, and it shall also submit to the 
Board of Trustees a printed or typewritten report of each of its meetings, and at 
the annual meeting shall submit to the Board a report for publication. The Execu- 
tive Committee shall have power to authorize the purchase, sale, exchange, or 
transfer of real estate. 

4. The Executive Committee shall have general charge and control of all ap- 
propriations made by the Board. 

5. The Finance Committee shall consist of five members to be elected by the 
Board of Trustees by ballot for a term of three years. 

6. The Finance Committee shall have custody of the securities of the corporation 
and general charge of its investments and invested funds, and shall care for and 
dispose of the same subject to the directions of the Board of Trustees. It shall have 
power to authorize the purchase, sale, exchange, or transfer of securities and to 
delegate this power. It shall consider and recommend to the Board from time to 
time such measures as in its opinion will promote the financial interests of the 
Institution, and shall make a report at each meeting of the Board. 

7. The Auditing Committee shall consist of three members to be elected by the 
Board of Trustees by ballot for a term of three years. 

8. The Auditing Committee shall, before each annual meeting of the Board of 
Trustees, examine the accounts of business transacted under the Finance Committee 
and the Executive Committee. They may avail themselves at will of the services 
and examination of the Auditor appointed by the Board of Trustees. They shall 
report to the Board upon the collection of moneys to which the Institution is entitled, 
upon the investment and reinvestment of principal, upon the conformity of expen- 

xvii 



CARNEGIE INSTITUTION OF WASHINGTON 

ditures to appropriations, and upon the system of bookkeeping, the sufficiency of 
the accounts, and the safety and economy of the business methods and safeguards 
employed. 

9. All vacancies occurring in the Executive Committee and the Finance Committee 
shall be filled by the Trustees at the next regular meeting. In case of vacancy in 
the Finance Committee or the Auditing Committee, upon request of the remain- 
ing members of such committee, the Executive Committee may fill such vacancy 
by appointment until the next meeting of the Board of Trustees. 

10. The terms of all officers and of all members of committees shall continue until 
their successors are elected or appointed. 

Article VI 

FINANCIAL ADMINISTRATION 

i. No expenditure shall be authorized or made except in pursuance of a previ- 
ous appropriation by the Board of Trustees, or as provided in Article V, paragraph 
6, hereof. 

2. The fiscal year of the Institution shall commence on the first day of November 
in each year. 

3. The Executive Committee, at least one month prior to the annual meeting in 
each year, shall cause the accounts of the Institution to be audited by a skilled ac- 
countant, to be appointed by the Board of Trustees, and shall submit to the annual 
meeting of the Board a full statement of the finances and work of the Institution 
and a detailed estimate of the expenditures of the succeeding year. 

4. The Board of Trustees, at the annual meeting in each year, shall make general 
appropriations for the ensuing fiscal year; but nothing contained herein shall pre- 
vent the Board of Trustees from making special appropriations at any meeting. 

5. The securities of the Institution and evidences of property, and funds invested 
and to be invested, shall be deposited in such safe depository or in the custody of 
such trust company and under such safeguards as the Trustees and Finance Com- 
mittee shall designate; and the income available for expenditure of the Institution 
shall be deposited in such banks or depositories as may from time to time be desig- 
nated by the Executive Committee. 

6. Any trust company entrusted with the custody of securities by the Finance 
Committee may, by resolution of the Board of Trustees, be made Fiscal Agent of 
the Institution, upon an agreed compensation, for the transaction of the business 
coming within the authority of the Finance Committee. 

Article VII 

AMENDMENT OF BY-LAWS 

i. These by-laws may be amended at any annual or special meeting of the Board 
of Trustees by a two-thirds vote of the members present, provided written notice 
of the proposed amendment shall have been served personally upon, or mailed to 
the usual address of, each member of the Board twenty days prior to the meeting. 

xviii 



ABSTRACT OF MINUTES OF THE FORTY-FOURTH MEETING OF 

THE BOARD OF TRUSTEES 

The meeting was held in New York in the Board Room of the Carnegie Cor- 
poration of New York on Friday, December 18, 1942. It was called to order at 
11 : 00 a.m. by the Chairman, Mr. Forbes. 

Upon roll call, the following Trustees responded: Thomas Barbour, lames F. Bell, 
Robert Woods Bliss, Lindsay Bradford, Frederic A. Delano, Homer L. Ferguson, W. 
Cameron Forbes, Walter S. Gifford, Herbert Hoover, Walter A. Jessup, Frank B. 
Jewett, Alfred L. Loomis, Roswell Miller, Seeley G. Mudd, Henry R. Shepley, Richard 
P. Strong, Frederic C. Walcott, and Lewis H. Weed. The President of the Institu- 
tion, Dr. Vannevar Bush, was also in attendance. 

The minutes of the forty-third meeting were approved as printed and submitted 
to the members of the Board. 

Reports of the President, the Executive Committee, the Auditor, the Finance Com- 
mittee, the Auditing Committee, and of Chairmen of Divisions, Directors of Depart- 
ments, and Research Associates of the Institution were presented and considered. 

The following appropriations for the year 1943 were authorized: 

Pension Fund $ 60,000 

Administration (including Investment Office and Insurance) . 130,580 
Publications (including Office of Publications and Public 

Relations) 22,380 

Departmental Research Operations 954,270 

$1,167,230 

The Chairman reported the death of Stewart Paton. As a result of balloting Hen- 
ning W. Prentis, Jr., President of the Armstrong Cork Company, Lancaster, Penn- 
sylvania, was elected to fill the existing vacancy in the Board. 

Mr. Forbes was re-elected Chairman of the Board, Mr. Gifford was re-elected 
Vice-Chairman, and Mr. Delano was re-elected Secretary, each for the ensuing 
period of three years. 

Walter A. Jessup, Henry R. Shepley, and Lewis H. Weed were re-elected members 
of the Executive Committee for a period of three years. 

Walter S. Gifford, Elihu Root, Jr., and Frederic C. Walcott were re-elected members 
of the Finance Committee for a period of three years. 

Frederic A. Delano was re-elected Chairman of the Auditing Committee for a 
period of three years, and Homer L. Ferguson and James W. Wadsworth were 
re-elected members of this Committee for the same period. 

xix 



CARNEGIE INSTITUTION OF WASHINGTON 

Upon recommendation of the Executive Committee, article 2, section 1 of the 
By-Laws of the Institution was amended to read as follows: 

"The annual meeting of the Board of Trustees shall be held in the City of Washington, 
in the District of Columbia, on the first Friday following the second Thursday of Decem- 
ber in each year unless the date and place of meeting are otherwise ordered by the 
Executive Committee." 

The meeting adjourned at 12:50 p.m., whereupon members journeyed to luncheon, 
upon invitation of Mrs. Carnegie, at her home. 



xx 



REPORT OF THE EXECUTIVE COMMITTEE 
For the Year Ending October 31, 1942 

To the Trustees of the Carnegie Institution of Washington: 

Gentlemen : Article V, section 3 of the By-Laws provides that the Executive Com- 
mittee shall submit, at the annual meeting of the Board of Trustees, a report for 
publication; and Article VI, section 3 provides that the Executive Committee shall 
also submit, at the same time, a full statement of the finances and work of the In- 
stitution and a detailed estimate of the expenditures for the succeeding year. In 
accordance with these provisions, the Executive Committee herewith respectfully 
submits its report for the fiscal year ending October 31, 1942. 

During this year the Executive Committee held five meetings, printed reports of 
which have been mailed to each Trustee and constitute a part of this report. 

A statement of activities of the Institution is contained in the report of the President, 
which has been considered and approved by the Executive Committee, and is sub- 
mitted herewith. The Executive Committee is gratified at the extent to which the 
government has called upon the Institution for cooperation in war research, includ- 
ing administrative services by the President and technical services by the scientific 
staff. Such contributions serve a national purpose and tend also to expand the Insti- 
tution's scope of usefulness in its normal sphere. The detailed estimate of expendi- 
tures for the succeeding year contained in the report of the President has been con- 
sidered by the Executive Committee, which has approved the recommendations of 
the President in respect thereto and has provisionally approved the budget estimates 
based thereon and submitted therewith. Close attention has been given both by the 
Executive Committee and by the Finance Committee to the question of availability 
of funds for Institution activities in 1943, and budget recommendations are based 
upon the judgment of these Committees with respect to financial policy during the 
present national emergency. 

The Board of Trustees, at its meeting of December 12, 1941, appointed Arthur 
Young and Company to audit the accounts of the Institution for the fiscal year ending 
October 31, 1942. The report of the Auditor, including a balance sheet showing assets 
and liabilities of the Institution on October 31, 1942, is submitted as a part of the 
report of the Executive Committee. 

In addition to the report of the Auditor there is also submitted a financial state- 
ment for the fiscal year ending October 31, 1942, showing funds available for expendi- 
tures and amounts allotted by the Executive Committee, a customary statement of 
receipts and disbursements since the organization of the Institution on January 28, 
1902, and a schedule of real estate and equipment at original cost. These statements 
together with the tables in the Auditor's report comprise a full statement of the 
finances of the Institution. 

A vacancy exists in the membership of the Board of Trustees by reason of the 
death of Stewart Paton on January 7, 1942. 

Tenure of office of the following officers of the Board of Trustees will expire at the 
annual meeting in December: Mr. Forbes, Chairman of the Board; Mr. Gifrord, 

xxi 



Vice-Chairman of the Board; and Mr. Delano, Secretary of the Board. Tenure of 
office of Messrs. Jessup, Shepley, and Weed as members of the Executive Committee, 
of Messrs. Gifford, Root, and Walcott as members of the Finance Committee, and of 
Messrs. Bliss, Delano, and Wadsworth as members of the Auditing Committee will 
also expire at the annual meeting. 

W. Cameron Forbes, Chairman 
Vannevar Bush 
Frederic A. Delano 
Walter S. Gifford 
Walter A. Jessup 
Henry R. Shepley 
Frederic C. Walcott 
Lewis H. Weed 
November 6, ig^2 



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XXIV 



Real Estate and Equipment, Original Cost 

Administration (October 31, 1942) 
Washington, D. C. 
Building, site, and equipment $848,927.91 

Division of Plant Biology (September 30, 1942) 
Stanford University, California (Headquarters) 

Buildings and grounds $74,423.46 

Laboratory 38,655.20 

Library 25,585.21 

Operating equipment 13,901.82 152,565.69 

Department of Embryology (September 30, 1942) 
Wolfe and Madison Streets, Baltimore, Maryland 

Library $4,038.76 

Laboratory 18,726.82 

Administration 7,919.09 30,684.67 

Department of Genetics (September 30, 1942) 
Cold Spring Harbor, Long Island, New York 

Buildings, grounds, field $289,989.35 

Operating equipment 33,591.88 

Laboratory apparatus 36,606.37 

Library 51,259.32 

Archives 45,488.90 456,935.82 

Geophysical Laboratory (September 30, 1942) 
2801 Upton Street N.W., Washington, D. C. 

Building, library, operating appliances $290,626.05 

Laboratory apparatus 171,304.96 

Shop equipment 21,103.00 483,034.01 

Division of Historical Research (September 30, 1942) 
Administration Building, Washington, D. C. 

Operating equipment $31,953.69 

Library 10,809.62 42,763.31 

Nutrition Laboratory (September 30, 1942) 
29 Vila Street, Boston, Massachusetts 

Building, office, shop, and library $134,258.06 

Laboratory apparatus 32,669.28 166,927.34 

Mount Wilson Observatory (September 30, 1942) 
Pasadena, California 

Buildings and grounds $222,458.33 

Shop equipment 47,255.77 

Instruments 684,986.05 

Furniture and operating appliances 147,148.26 

Hooker 100-inch reflector 638,507.51 1,740,355.92 

Department of Terrestrial Magnetism (September 30, 1942) 
5241 Broad Branch Road N.W., Washington, D. C. 

Building, site, and office $253,369.45 

Survey equipment 93,475.51 

Instruments, laboratory, and shop equipment 464,437.47 811,282.43 

$4,733,477.10 

XXV 



REPORT OF AUDITORS 

To the Board of Trustees 
Carnegie Institution of Washington 
Washington, D. C. 

We have made an examination of the books and accounts of Carnegie Institution 
of Washington for the year ended October 31, 1942. 

Income from investments and other sources has been duly accounted for and all 
disbursements were evidenced by paid voucher checks and/or properly approved 
invoices. The cash and securities were verified by certificates received from deposi- 
tories and custodians. As in past years, the detail accounts of the Departments of 
Research in the field have been audited by the Bursar of the Institution, and we are 
of the opinion, as a result of reviewing the internal audit methods in force, that such 
internal audit is satisfactorily conducted. 

The securities are stated at cost, amortized cost, or value at date acquired, this 
being the established custom of the Institution. In accordance with a recommenda- 
tion made in February 1940 by the Institution's Finance Committee, all premiums 
on all obligations purchased subsequent to January 1, 1940 are being amortized on 
a straight-line basis to the date on which an obligation is first callable or payable at 
par. The amortization of the premiums applicable to the year ended October 31, 1942 
amounted to $15,694.46 and has been deducted from the cost of such obligations. 

Real estate and equipment are stated at original cost and books on hand for sale 
at their sales prices. No provision has been made for depreciation of property owned 
by the Institution. 

We inspected certified copies of the minutes of the meetings of the Board of 
Trustees and Executive Committee as authority for the appropriations and allotments 
made during the year. 

In our opinion, on the basis of valuations stated above, the accompanying balance 
sheet, statement of receipts and disbursements, and detailed schedule of securities 
properly present the financial position of Carnegie Institution of Washington at 
October 31, 1942 and the transactions for the year ended that date. 

Arthur Young & Company 
Accountants and Auditors 
New York, N. Y. 
November 25, 7942 



xxvi 



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XXV111 



Schedule on Securities 



Aggregate 

par or 

nominal value 



Description 



Ma- 
turity 



Cost, amortized 

cost, or 

value at date 

acquired 



$300,000 

120,000 

460 , 000 

575,000 

304,000 

312,000 

200,000 

800,000 

1,239,000 

300,000 

350,000 

50,000 

50,000 

50,000 



U.S. 

u. s. 

u. s. 

U.S. 

u. s. 
u. s. 
u. s. 
u. s. 
u. s. 
u. s. 
u. s. 
u. s. 

U.S. 
U. S. 



United States Government Bonds 



Guar. Federal Farm Mtg. Corp. 3s 

Guar. Reconstruction Finance Corp. Notes, Is . 

of America Treasury Notes 1 Ks 

of America Treasury 2s 

of America Treasury 2s 

of America Treasury 2s 

of America Treasury 2s 

of America Treasury 2 K s 

of America Treasury 2 Ks 

of America Treasury 2 Ks 

of America Treasury 2 Ks 

of America Savings Defense "G" 2 Ks 

of America Savings Defense "G" 2 Ks 

of America Savings Defense "G" 2 Ks 



1949-44 

1944 

1946 

1950-48 

1951-49 

1951-49 

1952-50 

1955-52 

1954-52 

1958-56 

1967-62 

1953 

1954 

1954 



$309 

120 

462 

579 

304 

312 

200 

800 

,245 

300 

350 

50 

50 

50 



.210.93* 
000.00 
.084.38 
002.95* 
,000.00 
,000.00 
,000.00 
,000.00 
,487.46* 
,000.00 
,000.00 
,000.00 
,000.00 
,000.00 



$5,110,000 



Total United States Government . 



$5,131,785.72 



$55,000 

90,000 

100,000 

100,000 

57,000 

35,000 

91,000 

100,000 

100,000 

150,000 

100,000 

40,000 

250,000 

100,000 



Foreign Bonds 

Canada, Dom. of 5s 

Canadian National Ry. Co. 4Ks Guar 

Canadian National Ry. Co. 4 Ms Guar 

Canadian National Ry. Co. 5s Guar 

Canadian National Ry. Co. 5s Guar 

Canadian National Ry. Co. 5s Guar 

Canadian Pacific Ry. Co. Coll. Tr. 5s 

Province of Alberta Deb. 4 Ks 

Province of Alberta Deb. 5s 

Province of Manitoba Deb. 4Ks 

Province of Nova Scotia Deb. 4 Ks 

Province of Ontario Deb. 6s 

Shawinigan Water and Power Co. 1st Mtg. & Coll. Tr. S. F. 4Ks. 
City of Toronto Cons. Loan Deb. 5s 



1952 
1951 
1957 
1969 
1969 
1970 
1954 
1958 
1950 
1958 
1952 
1943 
1967 
1949 



$60,450.00 

90,329.34* 
112,000.00 
98,500.00 
62,344.44* 
38,119.77* 
90,835,11 
93,750.00 
101,150.00 
142,886.77 
100,312.50 
43,137.50 
238,510.42 
96,164.59 



$1,368,000 



Total Foreign . 



$1,368,490.44 



$93,000 

300,000 

75,000 

249,000 

23,900 

83,000 

50,000 

40,000 

100,000 

200,000 

25,000 

200,000 

150,000 

100,000 

100,000 

50,000 

98,000 

100,000 

65,000 

57,000 

50,000 

100,000 

100,000 

100,000 

200,000 

97,000 

100,000 

100,000 

141,000 

60,000 

50,000 

300,000 

150,000 

300,000 

195,500 

120,000 

263,000 

225,000 



Public Utility Bonds 



American Gas & Electric Co. S. F. Deb. 2 K s 

Arkansas Power & Light Co. 1st & Ref. Mtg. 5s 

Blackstone Valley Gas & Electric Co. Mtg. & Coll. Tr. 4s . 
Columbus & Southern Ohio Electric Co. 1st Mtg. 3Ks. . . . 

Commonwealth Edison Co. Conv. Deb. 3 Ks 

Commonwealth Edison Co. 1st Mtg. 3 Ks 

Consolidated Edison Co. of N. Y. Deb. 3 Ks 

Consolidated Edison Co. of N. Y. Deb. 3 Ks 

Detroit Edison Co. Gen. & Ref. Mtg. 4s 

Gulf States Util. Co. 1st Mtg. & Ref. 3Ks 

Houston Lighting & Power Co. 1st Mtg. 3 Ks 

Illinois Power & Light Corp. 1st & Ref. Mtg. 5s 

Louisiana Power & Light Co., 1st Mtg. 5s 

Metropolitan Edison Co. 1st Mtg. 4Ks 

Minnesota Power & Light Co. 1st & Ref. Mtg. 4Ks 

Monongahela West Penn Pub. Serv. Co. 1st Mtg. 4Ks. . . . 

Montana Power Co., 1st & Ref. Mtg. 3 M$ 

New Orleans Public Service Co. 1st & Ref. Mtg. 5s 

New York & Westchester Lighting Co., Deb. 5s 

North American Co., Deb. 3 Ks 

Northern States Power Co., 1st & Ref. Mtg. 3Ks 

Ohio Edison Co. 1st Mtg. 4s 

Ohio Power Co. 1st Mtg. 3 Ks 

Ohio Public Service Co., 1st Mtg. 4s 

Ohlahoma Gas & Electric Co., 1st Mtg. 3 Ks 

Oklahoma Natural Gas Co., 1st Mtg. 3 Ks 

Pacific Gas & Electric Co., 1st & Ref. Mtg. 3 Ks 

Pacific Gas & Electric Co., 1st & Ref. Mtg. 4s 

Public Service Co., of No. 111., 1st Mtg. 3 Ks 

Puget Sound Power & Light Co., 1st & Ref. Mtg. 4Ks. . . 
Puget Sound Power & Light Co., 1st & Ref. Mtg. 5Ks. . . 
Southern California Edison Co., Ltd. 1st & Ref. Mtg. 3s. . 
Southern Natural Gas Co., 1st Mtg. Pipe Line, S. F. 3Ks. 

Texas Electric Service Co., 1st Mtg. 5s 

Texas Power & Light Co., 1st & Ref. Mtg. 5s 

Toledo Edison Co., 1st Mtg. 3Ks 

Virginia Electric & Power Co., 1st & Ref. Mtg. 3Ks 

Wisconsin Electric Power Co., 1st Mtg. 3Ks 



1950 
1956 
1965 
1970 
1958 
1968 
1948 
1958 
1965 
1969 
1966 
1956 
1957 
1968 
1978 
1960 
1966 
1955 
1954 
1949 
1967 
1967 
1968 
1962 
1966 
1955 
1961 
1964 
1968 
1950 
1949 
1965 
1956 
1960 
1956 
1968 
1968 
1968 



$94,627.50* 

292,312.50 

76,875.00 

267,440.95* 

23,910.75 

85,712.87 

50,875.00 

40,730.00 

103,500.00 

213,500.00 

25,750.00 

196,750.00 

154,900.00 

109,470.00 

92,156.25 

52,000.00 

98,980.00 

99,200.00 

67,052.50 

58,122.50 

47,500.00 

100,266.25 

101,500.00 

102,625.00 

205,000.00 

104,507.80 

102,500.00 

104,000.00 

145,230.00 

56,550.00 

31,900.00 

313,970.20* 

154,112.94* 

292,700.00 

200,528.02 

121,800.00 

272,205.00 

232,875.00 



$4,810,400 



Total Public Utility. 



$4,893,636.03 



*After deduction for amortization of premiums on bonds purchased subsequent to January 1, 1940. Amortization 
is on a straight-line basis to the date on which bonds are first callable or payable at par. 

xxix 



Schedule of Securities — Continued 



Aggregate 

par or 

nominal value 



Description 



Ma- 
turity 



Cost, amortized 

cost, or 

value at date 

acquired 



$280,000 
51,000 
314,000 
25,000 
52,000 
75,000 



Communication Bonds 



American Telephone & Telegraph Co., Conv. Deb. 3s. . . 

American Telephone & Telegraph Co., Deb. 3 Ms 

American Telephone & Telegraph Co., Deb. 3 Ms 

Mountain States Telephone & Telegraph Co., Deb. 3 Ms. 
New England Telephone & Telegraph Co., 1st Mtg. 5s. . 
Southern Bell Telephone & Telegraph Co., Deb. 3 Ms. . . 



1956 
1961 
1966 
1968 
1952 
1962 



$307,703.79* 
51,510.00 
326,706.75 
25,500.00 
51,748.00 
72,375.00 



$797,000 



Total Communications. 



$835,543.54 



$50,000 
88,000 
82,000 



Railroad Equipment Trusts 



Erie R. R. Co., 4Ks Guar 

Illinois Central R. R. Co., 4 Ms. 
Pennsylvania R. R. Co. 2 Ms. . . 



1943 

1943-44 

1956 



$47,960.26 
84,397.19 
81,283.64 



$220,000 



Total Railroad Equipment Trusts. 



$213,641.09 



$200,000 

50,000 

100,000 

75,000 

50,000 

100,000 

150,000 

50,000 

75,000 

100,000 

50,000 

100,000 

70,000 

100,000 

200,000 

2,084,000 

100,000 

100,000 

50,000 



Railroad Bonds 

Atchison. Topeka & Santa Fe Ry. Co., 1st & Ref. Mtg. 4 Ms. . 

Central Pacific Ry. Co., 1st Ref. Mtg. 4s Guar 

Chesapeake & Ohio Ry. Co., Gen. Mtg. 4 Ms 

Chicago & VV. Indiana R. R. Co., Cons. 4s 

Great Northern Ry. Co., 1st & Ref. Mtg. 4 Ms Std 

Great Northern Ry. Co., Gen. Mtg. 5s 

Louisville & Nashville R. R. Co., 1st & Ref. Mtg. 4 Ms 

Oregon Short Line R. R. Co., Cons. 1st Mtg. 5s 

Pennsylvania R. R. Co., Gen. Mtg. 4j£s 

Pennsylvania R. R. Co., Cons. Mtg. 4 Ms 

Pittsburgh, Cin. Chi. & St. L. R. R. Co., Gen. Mtg. 5s Guar. 

Southern Rwy. Co., 1st Cons. Mtg. 5s 

Terminal R. R. Assn. of St. Louis S. F. Gen. Ref. Mtg. 4s. . . . 
Toledo & Ohio Central Ry. Co., Ref. & Imp. Mtg. 3M Guar. 

Union Pacific R. R. Co., 1st Mtg. R. R. & Land Grant 4s 

Union R. R. Co., Deb. 6s Guar 

Virginian Ry. Co., 1st Lien & Ref. Mtg. 3 Ms 

West Shore R. R. Co., 1st Mtg. 4s Guar 

Western Maryland Ry. Co., 1st & Ref. Mtg. 5 Ms 



1962 
1949 
1992 
1952 
1961 
1973 
2003 
1946 
1965 
1960 
1975 
1994 
1953 
1960 
1947 
1946 
1966 
2361 
1977 



$199, 
48, 
99, 
70, 
50, 

104, 

149, 
48, 
75, 

104, 
51, 

103, 
63 
99, 

218, 
2,084, 

102, 
78, 
42, 



500.00 
250.00 
464.29 
357.66 
113.59 
385.84 
475.00 
405.15 
918.75 
662.50 
898.98 
580.34 
603.92 
000.00 
942.61 
000.00 
250.00 
140.00 
677.19 



$3,804,000 



Total Railroad . 



$3,794,625.82 



$21,000 

100,000 

150,000 

4,000 

125,000 

98,000 

97,500 

86,000 

400,000 

300,000 

75,000 

150,000 

200,000 

1,925,000 

230,000 
148,000 



Industrial and Miscellaneous Bonds 

Allis-Chalmers Mfg. Co., Conv. S. F. Deb. 4s 

Atlantic Refining Co., Deb. 3s 

Bethlehem Steel Corp., Conv. S. F. Deb. 3 Ms 

Phelps Dodge Corp. Conv. Deb. 3 Ms 

Railway Express Agency, Serial Notes 1 Ms-2 Ms 

Republic Steel Corp. Gen. Mtg. 4 Ms 

Republic Steel Corp. Gen. Mtg. 4 Ms 

Scovill Manufacturing Co., Deb. 3 Ms 

Shell Union Oil Corp., Deb. 2 Ms 

Socony- Vacuum Oil Co. Deb. 2 Ms 

Socony- Vacuum Oil Co., Deb. 3s 

Standard Oil Co. of Calif. Deb. 2 Ms 

Standard Oil Co., of N. J. Deb. 2 Ms 

Tennessee Coal Iron & R. R. Co., Gen. Mtg. 5s (Payment Guar, by 

U. S. Steel Corp.) 

Westinghouse Electric & Mfg. Co., Deb. 2 Ms 

West Virginia Pulp & Paper Co., 1st Mtg. 3s 



1952 
1953 
1952 
1952 
1942-48 
1956 
1961 
1950 
1954 
1955 
1964 
1966 
1953 

1951 
1951 
1954 



$21,666.54 
103,521.97* 
148,750.00 
4,000.00 
125,000.00 
101,865.37* 
100,770.21* 

87,337.78* 
384,176.25 
312,990.20* 

78,000.00 
153,593.75* 
203,891.89* 

1,925,000.00 
233,258.33* 
146,520.00 



$4,109,500 



Total Industrial and Miscellaneous. 



$4,130,342.29 



$96,710.44 
100,000 

80,000 

90 , 000 

93,750 

90 , 000 



Mortgages 

Lawyers Mtg. Co., Guaranteed 1st Mtg. Ctfs., Series 18397T 4M%. . 
Lawyers Mtg. Co., Guaranteed 1st Mtg. Ctfs. 4M%- No. 29940T. . . 
Lawyers Title and Guar. Co., 5 M% Mtg. Par Ctfs. No. D 424421381.. 
N. Y. Title and Mtg. Co., Guaranteed 1st Mtg. Ctfs., 5M%. No. N97. 
N. Y. Title and Mtg. Co., Guaranteed 1st Mtg. Ctfs., 4M%. No. N86. 
Participating Ctf. in Consol. Bond and Mtg., S. E. corner Madison Ave. 
and 40th St., Manhattan, 4% 



1944 
1940 
1935 
1938 
1940 

1944 



$95,602.34 
98,022.20 
79,829.60 
90,000.00 
93,750.00 

90,000.00 



$550,460.44 



Total Mortgages. 



$547,204.14 



$20,769,360.44 



Bonds and Mortgages — Funds Invested . 



$20,915,269.07 



* After deduction for amortization of premiums on bonds purchased subsequent to January 1, 1940. Amortization 
is on a straight-line basis to the date on which bonds are first callable or i ayable at par. 

XXX 



Schedule of Securities — Continued 



Number of 
shares 



Description 



Cost, amortized 

cost, or 

value at date 

acquired 



100 
2,010 



,500 

1,500 

500 

600 

1,000 

1,125 

1,500 

225 

530 

5,000 

1,000 

1,000 

770 

550 

550 

600 

1,154 

1,000 

1,000 

3,100 



26,314 



Preferred Stocks 

American Brake Shoe and Foundry Co., 5}4% Cum. Pref 

American Cyanamid Co., 5% Cum. Pref 

Appalachian Electric Power Co., i l A% Cum. Pref 

Bethlehem Steel Corp. 7 % Cum. Pref 

J. I. Case Thresh. Machine Co., 7% Cum. Pref 

Cleveland Electric Illuminating Co., $4.50 Cum. Pref.. . . 

Deere & Company, 7 % Cum. Pref 

E. I. Du Pont de Nemours & Co., $4.50 Cum. Pref 

General Motors Corp. $5.00 Cum. Pref 

Grant Co. (W. T.) 5 % Cum. Pref 

Johns-Manville Corp. 7% Cum. Pref 

S. H. Kress Co., 6% Cum. Spl. Pref 

New York State Electric & Gas Corp. 5.10% Cum. Pref.. 

Northern States Power Co., $5.00 Cum. Pref 

Ohio Oil Co., 6% Cum. Pref 

Ohio Power Co., 4K% Cum. Pref 

Oklahoma Natural Gas Co., $5.50 Cum. Conv. Prior Pref 

Public Service Co., of Oklahoma 5% Cum. Pref 

Sherwin-Williams Co., 5% Cum. Pref 

Southwestern Gas & Electric Co., 5% Cum. Pref 

Standard Oil Co. of Ohio 5 % Cum. Pref 

U. S. Steel Corp., 7 % Cum. Pref 

Total Preferred Stocks 



$12,653.50 

22,471.25 

159,000.00 

183,637.50 

62,225.00 

68,112.25 

28,812.50 

116,125.00 

187,937.50 

7,642.76 

67,294.52 

58,269.00 

103,250.00 

103,000.00 

84,263.30 

59,925.00 

62,142.51 

60,900.00 

127,190.29 

110,350.00 

109,385.47 

443,407.57 



$2,237,994.92 



1,800 
2,000 
1,500 
3,300 
4,000 
200 
1,600 
2,600 



,900 

,400 

,500 

,900 

150 

,700 

,408 

,500 

,900 

980 

,150 

,600 

35 

10,600 

2,800 

7,600 

3,600 

440 

5,300 

900 

3,800 

1,000 

920 

,200 

864 

1,000 

800 

3 . 000 

4,500 

1,100 

1,600 

4,100 

760 

5,100 

2,000 

2,600 

3,200 

2,900 

2,500 

3,900 

1,200 

1,800 

900 

1,200 



1 



Common Stocks 

Air Reduction Company 

American Brake Shoe and Foundry Co 

American Can Company 

American Cyanamid Co. "B" 

American Radiator & Standard Sanitary Corp 

American Telephone & Telegraph Co 

Bethlehem Steel Corp 

Caterpillar Tractor Co 

Chase National Bank of N. Y 

Chrysler Corporation 

Commercial Credit Co 

Commercial Investment Trust Corp 

Commercial National Bank and Trust Co. of N. Y. . . . 

Continental Can Co 

Continental Insurance Co 

Continental Oil Co. of Delaware 

Deere & Company 

Dow Chemical Co 

E. I. Du Pont de Nemours & Co 

Eastman Kodak Co. of N. J 

First National Bank of N. Y 

General Electric Co 

General Foods Corporation 

General Motors Corporation 

W. T. Grant Co 

Guaranty Trust Co. of N. Y 

Gulf Oil Corp 

Hartford Fire Insurance Co 

Humble Oil & Refining Co 

Ingersoll-Rand Company 

Inland Steel Company 

Insurance Company of North America 

International Business Machines Corp 

International Harvester Co 

Johns-Manville Corp 

Kennecott Copper Corp 

Kresge Company (S. S.) 

Liggett & Myers Tobacco Co. "B" 

Monsanto Chemical Co 

Montgomery Ward & Co 

National Fire Insurance Co. of Hartford 

National Lead Co 

Newberry Co. (J. J.) 

New Jersey Zinc Co 

Owens-Illinois Glass Co 

Parke, Davis & Co 

Penney Co. (J. C.) 

Phelps Dodge Corp 

Pittsburgh Plate Glass Co 

Procter & Gamble Co 

Pullman Inc 

St. Joseph Lead Co 

(Continued on following page) 



$107 


905 


16 


87 


580 


<)S 


136 


846 


00 


95 


812 


55 


73 


114 


91 


21 


007 


50 


125 


270 


00 


175 


811 


00 


61 


775 


00 


226 


638 


50 


72 


258 


75 


112 


346 


24 


26 


880 


00 


118 


124 


50 


87 


913 


30 


149 


622 


50 


57 


720 


36 


117 


622 


28 


181 


861 


50 


252 


428 


75 


60 


925 


00 


417 


371 


50 


114 


615 


00 


390 


669 


00 


119 


318 


24 


115 


954 


00 


196 


858 


50 


69 


384 


68 


219 


969 


50 


107 


083 


00 


90 


662 


50 


79 


238 


15 


117 


056 


84 


82 


476 


25 


76 


687 


15 


129 


293 


38 


104 


500 


00 


110 


625 


00 


160 


453 


00 


220 


701 


08 


42 


942 


50 


108 


585 


50 


94 


190 


00 


172 


294 


50 


197 


239 


00 


107 


042 


00 


229 


123 


50 


145 


754 


79 


131 


399 


75 


100 


795 


82 


43 


073 


18 


54 


506 


57 



XXXI 



Schedule of Securities — Continued 



Number of 
shares 



Description 



Cost, amortized 

cost, or 

value at date 

acquired 



3.100 
1,500 
8 , 000 
4,000 
2,600 
1,858 
4.300 
2 , 800 
3,800 
1.500 
1,200 
600 
2,700 



Common Stocks — Continued 

Sears, Roebuck & Co 

Sherwin-Williams Co 

Socony- Vacuum Oil Co 

Standard Oil Co., of California 

Standard Oil Co. of Indiana 

Standard Oil Co. of N. J 

Texas Company 

Timken Roller Bearing Co 

Union Carbide & Carbon Corp 

United Fruit Company 

United States Gypsum Co 

United States Steel Corp 

Westinghouse Electric & Mfg. Co 

Total Common Stocks 

Common and Preferred Stocks — Funds Invested 

Aggregate Investments (Bonds and Stocks) 



$244 
147 

95 
127 

75 

98 
181 
136 
321 
109 
120 

61 
289 



,900.90 
,079.47 
, 645 . 00 
, 044 . 00 
,550.50 
,627.38 
,018.76 
,062.00 
, 683 . 50 
,972.00 
,301.00 
,573.34 
,816.50 



163,265 



5,708,602.98 



189.579 



$10,946,597.90 



51,861,866.97 



XXX11 



REPORT OF THE PRESIDENT 



OF THE 



CARNEGIE INSTITUTION OF WASHINGTON 



FOR THE YEAR ENDING OCTOBER 31, 1942 



REPORT OF THE PRESIDENT 

OF THE 

CARNEGIE INSTITUTION OF WASHINGTON 



In accordance with provisions of the By- 
Laws of the Institution, the President has 
the honor to report to the Board of Trus- 
tees on research activities of the year end- 
ing October 31, 1942, on financial and ad- 
ministrative matters, and on services which 
the Institution renders to the United States 
Government. 

At the last meeting of the Board, fol- 
lowing declaration of war, the Trustees 
adopted a resolution, in accordance with 
which the Institution is meeting all re- 
quests from the government for scientific 
aid as fully as its facilities and resources 
will permit. It was recognized that this 
policy would inevitably interrupt most of 
the normal program of the Institution. 
Accompanying scientific research for war 
purposes there is always an increase in 
fundamental knowledge; but war research 
is primarily applied research, and of rela- 
tively short range, whereas the normal 
program of the Institution is broad and 
basic. The action of the Trustees recog- 
nized that this Institution must place war 
research first, and suspend its peacetime 
activities in order to do so. The loss, even 
from a long-range point of view, will 
not be total, for the boundaries of knowl- 
edge are incidentally being extended, even 
though in strange ways, and some peace- 
time results will follow. No compromise 
is being made on this basis, however, and 
the requests of government are being met 
directly by the means best adapted to pro- 
duce results, by every laboratory and sci- 
entist of the Institution that can be diverted 
to advantage. 

After Pearl Harbor this country ceased 



to be an oasis in a world at war, and 
entered upon a period of strife and sacri- 
fice. To the Institution there is an intensi- 
fied opportunity to serve the nation in its 
peril, and the effort indeed calls for the 
sacrifice of precious things. To only a 
minor extent can we still hope to continue 
progress in paths of research toward dis- 
tant cultural objectives, and by keeping 
the road open avoid the loss of ground 
already gained. Not all scientific talents are 
of such nature as to be immediately and 
directly applicable to the waging of war, 
and hence the transition has occurred 
more rapidly in some departments than in 
others. The utmost effort of our research, 
however, wherever it has been possible to 
divert it successfully, is directed toward 
placing more powerful weapons in the 
hands of the youth of the land, and 
toward devising means better to protect 
their health in combat, by guarding against 
the rigors of disease and unnatural stress. 
To the extent of our ability and resources, 
and to the full effort of our personnel as 
it becomes determined how they can best 
serve, the Institution is committed to the 
service of the nation at war. 

When this war is over it will have been 
amply demonstrated that the full prosecu- 
tion of the war depended in no incon- 
siderable degree upon the presence in this 
country of an extensive and vigorous sys- 
tem of scientific research. This nation may 
again lapse into a dream of security; there 
may again be those who will indulge in 
wishful thinking to ward off the rigorous 
realities of a world of ambitious men. But 
it is hardly probable, after the present ex- 



CARNEGIE INSTITUTION OF WASHINGTON 



perience, that the American public as a 
whole will ever allow the national re- 
search effort to disintegrate. Whatever 
may be the changes of form that are pos- 
sible results of the stresses of a long war, 
we will certainly continue extensive sci- 
entific research in some form when peace 
comes. There are many kinds of valuable 
research, and many means of organizing 
for its furtherance. One very essential kind 
thrives best when independent groups, free 
of artificial constraint, compete in that 
pleasant contest for credit and recognition 
where rivalry is intense but increasingly 
fair and friendly, and where the entire 
product becomes the possession of the 
people as a whole. 

No matter what sort of world we live 
in after the war, the security of science 
should not depend wholly on its potential 
contribution to the direct needs of the 
state. There is a more fundamental reason 
than this for scientific research. This rea- 
son resides in the innermost gropings of 



the human mind to know and to under- 
stand, and free men everywhere and at all 
times have given expression, in the insti- 
tutions which they have created, to this 
urge for knowledge. The vicissitudes of 
an uncertain future may alter the organi- 
zational forms by which research is con- 
ducted, but so long as free men aspire, the 
effort to extend the boundaries of human 
knowledge will continue. In this the sci- 
entists of the Institution will have a part 
in the years after the war, for they are 
able scientists and are so recognized. The 
Institution itself may, however, need to 
find support in unexpected quarters, to be 
able to continue strongly on its way, if the 
exigencies of readjustment render its nor- 
mal method of continuing insufficient. On 
the other hand, when this war is over the 
service which the Institution has rendered 
will be known, and the benefits which it 
can confer in times of peace should be all 
the more keenly appreciated after an in- 
terval of stress. 



War Activities 



The policy of the Institution, in carrying 
on war research for government, has been 
to contribute the use of its facilities, the 
services of its regular scientific staff, and 
its regular overhead costs of providing ad- 
ministrative services and the like. The In- 
stitution is reimbursed for added out-of- 
pocket expenses directly attributable to the 
research for government. In addition, the 
Institution has loaned the services of some 
of its scientific personnel, while still con- 
tinuing them on the payroll. The result 
has been, as would be expected, that the 
over-all budgets of the several departments 
have been substantially unchanged by rea- 
son of undertaking an extensive war re- 
search program. This is the result that was 
desired, for it is consistent with the wish 
of the Trustees that the Institution should 



contribute to the war effort as far as its 
current resources would allow. It also 
makes it very clear, to one who reads our 
financial statement, that the Institution has 
certainly not profited financially by the 
effort; indeed, it has not asked government 
to carry the costs of its regular research as 
the effort became diverted from peace to 
war. 

Careful attention has been given to all 
details of handling government funds, and 
a special Revolving Fund for war projects 
has been established to cover advances re- 
quired for monthly payments of salaries 
and expenses representing out-of-pocket 
costs under contracts between the Institu- 
tion and the government. 

A total of 48 contracts, concerning re- 
search on 23 separate projects, have been 



REPORT OF THE PRESIDENT, 1942 



entered into with the Navy Department, 
the War Department, and the Office of 
Scientific Research and Development, in- 
volving a total expenditure of government 
funds aggregating $1,900,000. These con- 
tracts are as nearly as possible on a cost 
basis and without profit to the Institution. 
Every activity of the Institution has felt 
the effect of the war emergency, either 
through calls for personal service or 
through reorganization of programs due 
to work for the government. In some 
cases leaves of absence have permitted staff 
members to receive salaried appointments 
by the government. Services of others have 
been made available while they retained 
salaried connection with the Institution, 
working either in our own or in govern- 
ment laboratories. At the present time 34 
staff members are thus on leave, and 145 
others are giving full time to war research 
in our own laboratories or are devoting 
part time in various capacities to service 
for the government. Twenty-eight mem- 
bers of the scientific staff are either mem- 
bers, technical aides, or consultants of sec- 
tions of the National Defense Research 
Committee. Temporary employment of 
about 150 additions to personnel is like- 
wise required at present to enable the In- 



stitution to meet obligations of government 
contracts. 

In addition to his duties as Director of 
the Office of Scientific Research and De- 
velopment, the President of the Institution 
has been appointed by the Joint Chiefs of 
Staff as Chairman of a Joint Committee 
on New Weapons and Equipment. This 
Committee is a supporting body in the or- 
ganization of the Chiefs of Staff, and is 
concerned in an advisory capacity with the 
broad aspects of new weapons. 

The government has formally accepted 
donation by the Institution of space in the 
Administration Building for use by the 
Office of Scientific Research and Develop- 
ment, and has expressed its appreciation of 
this contribution. With the exception of 
a few offices in the old part of the build- 
ing, the government now utilizes all space 
available for office accommodations, and 
with the inauguration of work at night, 
the cost of operation and maintenance of 
the building by the Institution has steadily 
increased. On the other hand, certain ad- 
ministrative expenses which have normally 
occurred in former years in the form of 
travel and costs of meetings, lectures, and 
exhibits have been eliminated for the dura- 
tion of the war. 



Finances 



As has been evident for some years, the 
favorable financial situation of the Insti- 
tution which existed for three decades no 
longer continues. Excess of income over 
estimates for the year 1940 was sufficient 
to meet a small deficit in income for the 
year 1941 and leave a balance to apply 
toward the adjustment which will be nec- 
essary in balancing the budget of 1942. 
For the first time, however, we expect 
formally to draw upon reserves at the end 
of this year. 

The lower estimated income for the year 



1943 begins to render the problem acute, 
for the prospective yield for next year from 
present securities is approximately $160,000 
less than estimated income for 1942. At 
the same time it has become necessary, in 
accordance with the general trend, to in- 
crease salaries of mechanics and others 
whose services are essential to maintenance 
of research activities undertaken in the 
interest of the war effort. It is possible to 
reduce operating expenses to some degree, 
but it remains essential to keep our operat- 
ing units intact in many instances so that 



CARNEGIE INSTITUTION OF WASHINGTON 



we may continue to render full-time service 
to the government. On the other hand, 
by reason of economies we have available 
funds in the form of balances to carry over 
to meet the need for support of special 
Institution projects and for publication 
without adding to the 1943 budget for such 
purposes. 

With these considerations in mind, the 
budget for next year has been set up 
with a view to reducing to a minimum 
the call which will have to be made upon 
funds other than current income. 

It is disturbing to present, for the first 
time in the history of the Institution, a 
budget which involves even a small pre- 
dicted deficit. It is true that we have 
ample reserves for several years of deficit 
operation, and it is also true that current 
income could be increased, so that no pre- 
dicted deficit would be necessary, by simply 
investing less conservatively, if the added 
risk were genuinely warranted. But, as 
matters stand, there is formally a small 
predicted deficit for 1943. 

However, the broad question of where 
we are headed as an Institution, from a 
financial standpoint, is so great that it 
submerges the minor question of a deficit, 
or a series of deficits, in the war years. Our 
entire income is from endowment, and we 
are peculiarly vulnerable to trends which 
adversely affect endowed institutions. Un- 
like the universities, we have no income 
from student fees. Unlike the foundations, 
we carry extensive continuing operations, 
and cannot materially cut our grants to fit 
our income. If the readjustment after the 
war further reduces endowment income, 
we may indeed be in severe straits. 

There is still some room for retrench- 
ment. The deficit appears, for one reason, 
because we carry the annual grant from 
Carnegie Corporation of New York in a 
separate account, since it is of terminating 



nature, and because we still hold to the 
objective which was prominently in mind 
when that grant was made, of extending 
the influence and aid of the Institution over 
broad scientific fields which we share with 
others. But the downward trend of in- 
come, from $1,695,900 in 1936 to an esti- 
mated income of $1,175,000 for 1943, if it 
continues, will soon cause us to retrench 
until only the regular operation of our 
departments remains, and will then em- 
barrass our attempt to continue even these 
in full health. 

A number of our staff have gone on 
leave of absence in order to accept posts in 
the armed services or other war agencies, 
under conditions where we have been tem- 
porarily relieved of salary payments. Their 
names have remained on our rolls, we have 
continued their benefits under our retire- 
ment provision, and, where conditions 
warranted, we have supplemented their 
government salaries. Moreover, we still 
include their salaries in making up the 
departmental estimates, for we expect these 
men back in time, and the inclusion of 
their salaries hence gives a true picture of 
our situation. For this reason there will 
be more than the usual unexpended funds 
reported by the departments at the end of 
this year. Part of the excess has been used, 
by transfer within department budgets, to 
defray certain unusual extra costs of serv- 
ice to government which it was felt should 
not be included in the reimbursement ac- 
count, but the bulk of such salary provision 
will return to us. It can be placed in re- 
serves, where it will need to be drawn 
upon for current operating expenses next 
year in view of sharply decreased income. 

In accordance with action of the Board 
of Trustees at its last meeting, a General 
Reserve Fund has been established by 
merging the former Special Emergency 



REPORT OF THE PRESIDENT, 1942 



Reserve Fund with the Insurance Fund. 
At the same time the former so-called Re- 
serve Fund was designated the Capital 
Reserve Fund, inasmuch as the principal 
of this fund originated as a result of stipu- 
lation of the Founder of the Institution in 
connection with his gift of 191 1. In view 
of these arrangements, insurance protection 
for Institution property has now been in- 
creased through commercial agencies. Fire 
insurance, with extended coverage, has 
been written for a five-year period, and 
war damage insurance has been secured on 
a yearly basis on property which may be 
subjected to such hazards. 

As an added protection in connection 
with war risk, duplicate copies of impor- 
tant or irreplaceable administrative and 
financial records have been deposited else- 
where than in the Administration Build- 
ing. 



In an effort to cooperate with the appeal 
of the government for voluntary purchase 
of war bonds, the Institution has opened a 
special bank account for custody of funds 
derived from payroll deductions authorized 
by staff members for such purchase of gov- 
ernment securities. 

Since its organization the Institution has 
enjoyed exemption from federal taxes and 
from real-estate taxes in the District of 
Columbia. During recent months con- 
sideration has been given by authorities 
of the District of Columbia to the question 
of placing the Institution on the tax roll 
along with a small group of other organi- 
zations which own real estate in Washing- 
ton but whose programs are nation-wide 
in scope. There is indication that this 
question will be reasonably resolved, and 
that the Institution's present status will be 
maintained. 



Review 



Despite interruptions to established re- 
search plans and withdrawal of many 
members of the scientific staff for war 
research, reports of Directors of Depart- 
ments indicate an amount of activity in 
connection with the Institution's normal 
program which is remarkable, although it 
is now rapidly decreasing. The customary 
interpretative statements of these activi- 
ties appear in the Directors' reports in the 
Year Book. The following brief additional 
comments will serve as an introduction to 
the full formal record. 

Although many staff members of the 
Mount Wilson Observatory are giving full 
time to war service, and essentially every 
remaining member of the scientific staff is 
contributing in some way toward the solu- 
tion of military problems, the program of 
astronomical research has not altogether 
ceased and a few important advances have 
been made. Among the results of the 



many investigations undertaken at the Ob- 
servatory, especial reference may be made 
to the increase in our knowledge of solar 
prominences, solar rotation, and the gen- 
eral magnetic field of the sun through the 
application of powerful interference meth- 
ods; to the analysis of the gaseous clouds 
of interstellar space; and to the probable 
solution of the problem of long standing 
of the direction of rotation of the outer 
systems of stars known as the extragalactic 
spiral nebulae. The conclusion that the 
spiral arms are trailing in all such nebulae 
now seems to be well founded. A dis- 
covery of some dramatic interest is that of 
the remnants of Kepler's celebrated super- 
nova of 1604. Faint wisps of nebulosity 
scattered over a field some 80 seconds in 
diameter and a small fan-shaped nebula 
showing a high radial motion seem to be 
all that remains of the expanding shells 



CARNEGIE INSTITUTION OF WASHINGTON 



thrown off in the great outburst of the 
original star. 

Activities at the Geophysical Laboratory 
and the Department of Terrestrial Mag- 
netism have been directed so exclusively 
to war research that there is little to re- 
port from these laboratories. On the basis 
of service which the cyclotron at the De- 
partment of Terrestrial Magnetism will be 
able to render in connection with war re- 
search, and at the instance of the Com- 
mittee on Medical Research of OSRD, 
priorities have now been obtained for ma- 
terials necessary for completion of this 
apparatus. It is expected that the cyclotron 
will be available for use during the coming 
winter. 

Dr. Spoehr, Chairman of the Division of 
Plant Biology, reports a number of interest- 
ing experiments during the past year on 
the variability of the photosynthetic proc- 
ess, on certain structural elements in the 
higher plants, and on differences and rela- 
tionships in climatic races of flowering 
plants. Several projects have recently been 
completed having to do with the influ- 
ence of a desert environment on plant 
growth. It has been discovered that dia- 
toms and related plants contain chloro- 
phylls which are different from those of 
land plants. This is indication of funda- 
mental differences in the photosynthetic 
apparatus between the two groups of 
plants. It will be of importance to de- 
termine whether this diversity is reflected 
in differences in the mechanism of the 
photosynthetic process and in the nature 
of the resulting products. 

The work of the Department of Em- 
bryology has continued to develop along 
lines set forth by the Director, Dr. Corner, 
in last year's report. A significant addition 
to the collection of embryos is announced 
this year. Dr. Hertig and Dr. Rock, of 
Boston, working during the past six years 



with financial aid from the Carnegie Cor- 
poration, have obtained a remarkable col- 
lection of human embryos of very early 
stages. By study of these specimens our 
knowledge of the development of the 
human embryo has been pushed back about 
one week, to the eighth day of gestation. 
Plans for obtaining still earlier stages are 
being worked out. This year marks also 
completion of a long study of the develop- 
ment of the rhesus monkey by Dr. Streeter, 
Dr. Heuser, and Dr. Hartman. Important 
studies on the organs accessory to the em- 
bryo, which have reached the stage of pub- 
lication, are those of Dr. Flexner and Dr. 
Gellhorn on the physiology of the placenta, 
and of Dr. Speert on various physiological 
states and hormone relationships of the 
mammary gland. 

Under the leadership of Dr. Demerec, 
there has been continuation of effective 
cooperation between the Department of 
Genetics and the Long Island Biological 
Association at Cold Spring Harbor. It is 
a pleasure also to report that Dr. Blakeslee, 
who retired as Director of this Department 
last year, has accepted a research post at 
Smith College, where, with cooperation of 
the Institution, he will have continued op- 
portunity to go on with Datura researches 
under favorable conditions. 

Detailed studies at the Department of 
Genetics, made by Dr. Demerec, Dr. Hol- 
laender, and Dr. Fano, of genetic effects 
produced by X rays, ultraviolet rays, and 
neutrons show consistent differences be- 
tween the actions of these radiations. As 
compared with gene mutations, fewer 
chromosomal breaks are produced by ultra- 
violet radiation than by X rays; whereas 
neutrons show a higher rate of chromo- 
somal breaks than X rays. Working with 
maize, Dr. McClintock has obtained im- 
portant evidence regarding the fusion of 
broken chromosome ends. She found that 



8 



REPORT OF THE PRESIDENT, 1942 



broken ends retain their capacity for fusion 
for a certain period of time after breakage, 
but that after that period has passed they 
"heal" and are unable to fuse again. Nearly 
six years of study of the role of hormones 
in the regulation of the maternal instinct 
in rats have been concluded by Dr. Riddle 
and his associates, who found that pitui- 
tary-gland hormones play an important 
part in the production of stimuli that re- 
sult in unlearned maternal behavior. Dr. 
Warmke has been cooperating with the 
Bureau of Plant Industry of the U. S. 
Department of Agriculture on several 
problems arising from the present war 
emergency. He is experimenting with the 
rubber-producing Russian dandelion and 
with fiber-producing hemp. 

The small staff of the Nutrition Labora- 
tory has been engaged in important war 
research in cooperation with groups at the 
Harvard Medical School. Work has con- 
tinued, however, on respiratory exchange, 
by measurements on diabetic patients 
through cooperation with Dr. Joslin and 
Dr. Root, and certain studies on basal 
metabolism have been continued. 



It has been possible for the most part 
for the Division of Historical Research to 
carry through the program of field studies 
planned by Dr. Kidder for the past season, 
in a series of archaeological explorations 
and excavations in Yucatan, Guatemala, 
Honduras, and Nicaragua. These projects 
have also been of interest in supplementing 
the government's program of inter-Ameri- 
can cultural relations. Certain members of 
the staff of the Division have remained in 
Central America to complete their work. 
Additional data have been obtained con- 
cerning the discovery of human footprints 
in Nicaragua, and this was reported to the 
members of the Board. At the important 
archaeological site of Kaminaljuyu, outside 
Guatemala City, rich caches of pottery and 
jades have been found, and also many fine 
stone sculptures. Studies of such material 
which are now proceeding will add much 
to our understanding of the events of 
Maya history. Knowledge which staff 
members of this Division possess with 
regard to geographical and economic con- 
ditions in Central America is proving of 
aid in connection with the government's 
war program. 



Stewart Paton 



Stewart Paton died on January 7, 1942, 
in his seventy-sixth year. He was elected 
a Trustee of the Institution in December 

1915, and at the time of his death had been 
in continuous service for a longer period 
than any other member of the Board. At 
the meeting of the Board on December 15, 

1916, he was elected a member of the 
Executive Committee, on which he served 
until his resignation on account of ill 
health, in December 1938. 

Dr. Paton was greatly interested in 
affairs of the Institution, and his counsel 
and advice were often sought, particularly 



with regard to activities in the fields of 
biology and genetics. His personal con- 
tributions as a scientist and physician con- 
cerned studies in human behavior and took 
the form of pioneering efforts in every 
forward movement in psychiatry in the 
United States during the period of his 
career. 

He takes his place as a member of that 
eminent group of former Trustees consist- 
ing of John S. Billings, S. Weir Mitchell, 
Theobald Smith, William S. Thayer, 
Henry P. Walcott, and William H. Welch. 



REPORTS OF DEPARTMENTAL ACTIVITIES 
AND COOPERATIVE STUDIES 

ASTRONOMY 

Mount Wilson Observatory 
Special Projects 

TERRESTRIAL SCIENCES 

Geophysical Laboratory 

Department of Terrestrial Magnetism 

Special Projects 

BIOLOGICAL SCIENCES 

Division of Plant Biology 

Department of Embryology 

Department of Genetics 

Nutrition Laboratory 

Special Projects 

HISTORICAL RESEARCH 

Division of Historical Research 
Special Projects 



MOUNT WILSON OBSERVATORY 

Pasadena, California 
WALTER S. ADAMS, Director 



Since the entry of the United States into 
the war, two members of the scientific 
staff have been given indefinite leave of 
absence to devote all their time to investi- 
gations on military problems. A third 
member has been engaged, to the exclusion 
of all other work, upon various projects 
initiated by the Instrument Section of the 
National Defense Research Committee. 
The Office of Scientific Research and 
Development has entered into contracts 
with the Carnegie Institution for such 
work. Nearly all the remaining members 
of the staff have helped to contribute, each 
according to his special ability, to the solu- 
tion of the many types of questions which 
have arisen in these investigations. A 
very large part of the time of the optical 
shop (enlarged considerably during the 
year), of the instrument shop, and of the 
engineering staff has been given to the 
design and construction of the instruments 
and equipment used in research projects 
relating to the war. 

Two members of the operating group on 
Mount Wilson volunteered for service in 
the military forces and have been in the 
Army since early in 1942. 

Although the scientific work of the Ob- 
servatory has necessarily been maintained 
under considerable difficulties, the year has 
been an active one in all its fields of re- 
search. The gradual decrease in sunspot 
activity has favored investigations requir- 
ing a quiescent sun, such, for example, 
as spectrographic studies of solar rotation 
and the general magnetic field of the sun. 
Observations of prominences have been 
numerous and have been aided greatly by 
the use of the quartz monochromator of 



the Ohman type designed for this purpose. 
No sunspots of the new cycle have as yet 
appeared, but they may normally be ex- 
pected within the next year or two. 

An extensive investigation of the infra- 
red solar spectrum to a limit of A13500, 
made in cooperation with Mrs. Sitterly, of 
the Princeton Observatory, is nearing com- 
pletion. The separation of solar from tel- 
luric lines and their identification accord- 
ing to element and energy level should 
make this catalogue of great value to solar 
physicists. 

In the field of stellar research, our knowl- 
edge of the nearer stars has been consider- 
ably extended by the continuing program 
of the measurement of distances by the 
trigonometric method. The intrinsic lu- 
minosities of stars derived in this way 
have been supplemented to a great extent, 
for more distant stars, by computations 
based upon proper motions and radial 
velocities as well as upon certain spectral 
characteristics. 

The fundamental importance of accu- 
rate determinations of stellar brightness 
has been recognized in several recent in- 
vestigations. In one of these the scale of 
photographic magnitudes has been ex- 
tended to 2o™5, primarily for the use of 
observers of faint stars in clusters and 
extragalactic nebulae. A very complete 
discussion of the colors of the stars in the 
Mount Wilson Polar Catalogue has led to 
interesting conclusions respecting space ab- 
sorption in this region, mean effective wave 
lengths, and the probable departure of 
stars from black-body radiation. Photoelec- 
tric measures of B-type stars through vari- 
ous filters indicate that the nature of ab- 



CARNEGIE INSTITUTION OF WASHINGTON 



sorbing dust is much the same throughout 
interstellar space. 

Stellar spectroscopy has always formed 
one of the major fields of investigation of 
the Observatory. In the past year especial 
attention has been given to physical stud- 
ies of certain classes of variable stars and 
individual stars of exceptional interest. 
Among the classes of variable stars the 
results have shown numerous interrelation- 
ships as regards luminosity, distribution, 
and motion; and individual spectra have 
served to emphasize remarkable problems 
in spectral variation, bright-line emission, 
and combinations of widely differing spec- 
tral characteristics. As an example, the 
discussion of the orbit of a spectroscopic 
binary of the Wolf-Rayet type throws con- 
siderable doubt upon the usually accepted 
view of the origin of the emission bands. 

The structure of the interstellar lines of 
ionized calcium in numerous stars has been 
examined with exceptionally high disper- 
sion, and double or multiple lines have 
been found in a large majority of the 
stars. The results afford a means of de- 
termining the distribution in various parts 
of the sky of individual gaseous clouds 
distinguished from one another by dif- 
ferences of motion in the line of sight. 

Investigations of galactic nebulae have 
to a large extent centered about those 
nebulae associated with outbursts of novae 
or supernovae. Direct photographs and 
spectroscopic studies of Nova Herculis 
(1934) show the emergence of an elliptical 
ring due to an expanding shell of finite 
thickness. The clearly separated diffuse 
and filamentary nebulosities of the Crab 
nebula, probably a remnant of the super- 
nova of 1054, have quite different spectra, 
that of the diffuse part being continuous, 
that of the filaments consisting of bright 
lines. Theoretical considerations indicate 
that the supernova before its outburst was 



a massive star of low hydrogen content, 
and that the greater part of its mass was 
lost in the outbreak, leaving a relatively 
small star of high temperature. 

An interesting and somewhat dramatic 
discovery is that a small fan-shaped nebula 
and various wisps of nebulosity scattered 
over a field 80" in diameter in the con- 
stellation of Ophiuchus are almost cer- 
tainly remnants of Kepler's supernova of 
1604. The region is heavily obscured, but 
the spectral characteristics of the fan- 
shaped nebulosity and its relatively high 
radial velocity afford strong evidence that 
it forms part of an expanding nebula. 

A detailed study of the pattern of ob- 
scuration in several extragalactic spiral 
nebulae indicates clearly which is the 
nearer side of these objects and hence the 
direction of inclination. When combined 
with the spectrographic data for numerous 
nebulae, these results define without am- 
biguity a direction of rotation, probably 
characteristic of extragalactic nebulae in 
general. The arms of the spirals are found 
to trail behind the nucleus. This gives 
what appears to be a definite answer to a 
problem of long standing in nebular re- 
search. 

In addition to determinations of mo- 
tions in extragalactic nebulae which have 
been accumulated rapidly in recent years, 
it has now become possible to make physi- 
cal studies of the spectra of some of the 
brighter nebulae. Such an investigation 
of the nuclear emission of three spirals 
through measurements of line widths and 
contours has been completed during the 
past year. 

Researches in the physical laboratory 
serve the purpose of contributing data 
both for the analysis of atomic and molec- 
ular spectra and for the study of astro- 
physical problems. Observations of the 



MOUNT WILSON OBSERVATORY 



spectra of rare earths and identification 
of their lines in the sun and stars afford 
an illustration of both purposes. Similarly, 
measurements in the laboratory of the 
statistical factors for spectral lines known 



as "/-values" have been applied to a deter- 
mination of the abundance of iron in the 
sun. The method has almost limitless ap- 
plications to the spectra of the brighter 
stars. 



STAFF AND ORGANIZATION 



Research Division 

Solar Physics: Seth B. Nicholson, Harold D. 
Babcock, Joseph Hickox, Edison Hoge, 
Edison Pettit, Robert S. Richardson, Mary 
F. Coffeen, Elizabeth S. Mulders, Myrtle 
L. Richmond, Louise Ware. 

Stellar Motions and Statistics: Adriaan van 
Maanen, Ralph E. Wilson, A. Louise 
Lowen. 

Stellar Photometry: Walter Baade, Harold 
Weaver, Mary C. Joyner. 

Stellar Spectroscopy: Walter S. Adams, 
William H. Christie, Theodore Dunham, 
Jr., Milton L. Humason, Alfred H. Joy, 
Paul W. Merrill, Roscoe F. Sanford, Gus- 
taf Stromberg, Olin C. Wilson, Ralph E. 
Wilson, Ada M. Brayton, Sylvia Burd, 
Cora G. Burwell, A. Louise Lowen. 

Nebular Photography, Photometry, and Spec- 
troscopy: Edwin P. Hubble, Walter Baade, 
Milton L. Humason, Rudolph Minkowski, 
Sylvia Burd. 

Physical Laboratory: Arthur S. King, John 
A. Anderson, Robert B. King. 

Editorial Division: Paul W. Merrill, editor; 
Elizabeth Connor, librarian; Alice S. 
Beach, secretary and stenographer. 

Alfred H. Joy has served as Secretary of 
the Observatory throughout the year. 

Research Associates 

Sir James Jeans, Dorking, England; Henry 
Norris Russell, Princeton University; 
Frederick H. Seares, Pasadena; Joel Steb- 
bins, University of Wisconsin. 

Dr. Russell spent the months of March 
and April 1942 in Pasadena, engaged 
chiefly in a term analysis of spectra of rare 



earths, especially neutral and ionized gado- 
linium. As always, his discussions of astro- 
physical problems with members of the 
staff have been stimulating and suggestive. 
Dr. Seares with the assistance of Miss Joy- 
ner has completed an extensive discussion 
of the colors of stars in the Mount Wilson 
Polar Catalogue, deriving effective wave 
lengths and color temperatures and apply- 
ing the results to black-body radiators of 
different temperatures. This investigation 
is now ready for publication. Dr. Stebbins 
during the summer of 1941 carried on 
measurements of the colors of numerous 
early-type stars and nebulae with his photo- 
electric photometers, being assisted in the 
observations by Mr. Bart Bouricius, of the 
University of Wisconsin. 

Temporary Associates 

Dr. S. A. Mitchell, Director of the Le- 
ander McCormick Observatory, spent the 
months of July and August 1941 in Pasa- 
dena measuring the radial velocities of 
faint stars in the fields of stars of known 
proper motion from spectrograms which 
he obtained with the 60-inch telescope. Dr. 
John C. Duncan, Director of the Whitin 
Observatory, continued his direct photo- 
graphic observations of selected nebulae 
and star fields. Dr. Erik Holmberg, of the 
Observatory of Lund, carried on nebular 
research during the summer and autumn 
months of 1941. He returned to Sweden 
in November 1941. Dr. G. P. Kuiper, of 
the Yerkes Observatory, spent two weeks 
of May 1942 in Pasadena in the measure- 



CARNEGIE INSTITUTION OF WASHINGTON 



ment of the proper motions of faint dwarf 
stars. Miss Elizabeth Scott, of the Uni- 
versity of California, assisted in several in- 
vestigations in stellar statistics during a 
stay of two months in the summer of 1941. 
Lieutenants Evinay and Erokan of the 
Turkish army visited the Observatory dur- 
ing the months of May and June 1942, for 
the purpose of studying its equipment and 
scientific program. Their journey was 
sponsored by the Department of State. Dr. 
Carl K. Seyfert, National Research Fel- 
low, has continued his work throughout 
the year on the spectra of extragalactic 
nebulae. 

Many other scientists have made brief 
visits to Mount Wilson and Pasadena dur- 
ing the past year. 

Instrument Construction 

Design: Edgar C. Nichols, Harold S. Kinney. 
Optical Shop: John S. Dalton, Donald O. 
Hendrix. 



Instrument Shop: Albert Mclntire, foreman; 
Elmer Prall, Myo C. Hurlbut, Fred Scherff, 
Oscar Swanson, Albert Labrow, Donald 
W. Yeager, machinists; Robert W. Kingan, 
assistant machinist; James Chapman, pat- 
tern maker; Harry S. Fehr, cabinet maker. 

Operation and Maintenance 

Office: Anne McConnell, bookkeeper; 
Sarah Shaw and Dorothea Neuens, stenog- 
raphers and telephone operators. 

Operation: Ashel N. Beebe, superintendent 
of construction; Sidney A. Jones, engineer; 
Kenneth de Huff, assistant engineer; 
Thomas A. Nelson, Boyd Thompson, 
Floyd Day, Louis S. Graf, night assistants; 
Anthony Wausnock and Mrs. Wausnock, 
stewards; Charles Dustman, Arnold T. 
Ratzlaff, George W. Foster, Lester Shade, 
janitors. 

Several of the individuals whose names 
are listed above have been associated with 
the Observatory for but part of the year. 



OBSERVING CONDITIONS 



The extraordinarily wet winter of 1940- 
1 941 was followed by an abnormally dry 
season in 1941-1942, the total precipitation 
amounting to only 20.97 inches. The snow- 
fall was 30 inches. Observing conditions, 
as indicated by the accompanying table 
applying to the 60-inch telescope, were 
very close to the normal. 

Owing to wartime conditions, the 
weekly evening lecture and public observa- 
tions with the 60-inch telescope were dis- 
continued in December. The exhibit hall 
on Mount Wilson with its numerous astro- 
nomical photographs and models has, 
however, been open every afternoon, and 
the regular daily lectures and demonstra- 
tions in the dome of the 100-inch telescope 
have been maintained. 





Observations 


Month 


All 
night 


Part of 
night 


None 


1941: 

July 

August 

September 

October 

November 

December 

1942; 

January 

February 

March 

April 

May 

June 


22 
25 
21 
15 
19 
6 

11 

12 
13 

5 
24 
28 


7 
4 
6 
6 
6 
6 

11 
7 
9 

14 
4 
2 


2 
2 
3 

10 
5 

19 

9 
9 
9 
11 
3 



Total 

Mean 30 years. . . 


201 
204 


82 
85 


82 
75 



MOUNT WILSON OBSERVATORY 



SOLAR RESEARCH 



Solar Photography 



Photographs of the sun were made on 
301 days of the year by Hickox, Hoge, 
Nicholson, and Richardson. These were 
distributed as follows: 

Direct photographs 604 

Ha spectroheliograms of spot groups, 

60-foot focus 760 

Ha spectroheliograms, 18-foot focus 1,170 

Ha spectroheliograms, 7-foot focus 4,000 

K2 spectroheliograms, 7-foot focus.. 18,000 

K2 spectroheliograms, 18-foot focus. . 1,130 

K prominences, 18-foot focus 1 A5° 

Sunspot Activity 

During the calendar year 1941 sunspot 
activity decreased notably from that of 
the preceding year. Observations were 
made on 294 days, on 2 of which no spots 
were visible. The monthly means of the 
number of groups observed daily during 
the past two and one-half years are shown 
in the accompanying table. 

In 1941, 252 sunspot groups were ob- 
served, 119 less than in 1940. The northern 
hemisphere was the more active, showing 
24 more groups than the southern hemi- 
sphere. 



Month 



January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November 

December 

Yearly average 



Daily number 



1940 1941 



4.3 

5.2 



7.7 
6.5 
5.3 
8.3 
6.9 
9.2 
5.8 
5.3 
6.8 
6.5 



6.5 



4.8 
5.5 
5.0 

2.7 



4.3 



1942 



3.3 
4.4 
4.9 
5.2 
2.6 
1.3 



Sunspot Polarities 



Magnetic polarities in each spot group 
have been observed at least once, so far 
as possible. The classification of the groups 
observed between July 1, 1941 and June 30, 
1942 is given in the accompanying table. 
As usual, "regular" groups in the north- 
ern hemisphere are defined as those in 
which the preceding spot has N (north- 
seeking) polarity and the following spot 
S polarity. In the southern hemisphere the 
polarities are reversed. 



Hemisphere 


Polarity 


Regular 


Irregular 


Unclassified 


North 

South 


93 

58 


1 
4 


41 
36 






Whole sun. . . . 


151 


5 


77 



Solar Prominences 

The monochromator designed for the 
Ha line has been used extensively by 
Pettit in studies of the solar prominences. 
Most of the photographs have been made 
on 35-mm film at intervals of 1 minute 
with a telescope of 45 feet equivalent focal 
length. Especial attention has been given 
to eruptive prominences, coronal promi- 
nences as related to sunspots, and pairs of 
interactive prominences with connecting 
streamers. In prominences so far studied, 
the material moves only in one direction 
along the streamers and no exchange of 
matter seems to occur. This implies that 
two prominences can have masses of gas 
with electrical fields of opposite sign, a 
result of considerable theoretical interest. 
The length of such streamers varies from 
a few thousand to several hundred thou- 
sand kilometers; the breadth varies much 
less, being usually from 500 to 1000 km 



8 



CARNEGIE INSTITUTION OF WASHINGTON 



and only rarely 4000 or 5000 km. Broad 
streamers deplete a prominence rapidly, 
two streamers 5000 km wide once having 
been observed to reduce a prominence 
70,000 km high and 55,000 km wide to a 
height of 46,000 km within an hour. 

Further study of 43 eruptive promi- 
nences shows that in 31 of them successive 
velocities were multiples by small whole 
numbers within the allowable errors of 
observation. In 12 an occasional velocity, 
usually the last of the series, was a multi- 
ple of the second preceding velocity in- 
stead of the first. This modification of the 
suggested law is required to explain only 
12 of the total of 86 velocities involved in 
the study. 

There seems to be no especially favored 
velocity in eruptive prominences, and the 
frequency of any velocity is roughly in- 
versely proportional to the velocity raised 
to the power 0.8. Measurements of both 
top and bottom of eruptive prominences 
show that as the gas cloud rises, the 
changes in velocity of the various parts 
take place within a few minutes of the 
same instant and in some cases nearly 
simultaneously. The heights at which 
changes in velocity occur show some tend- 
ency to maxima of frequency at 62,000 
and 162,000 km above the sun, but promi- 
nences have been observed to pass through 
both heights without changes in velocity. 

A study has been made by Pettit with 
the 150-foot tower telescope of the widths 
of lines in the spectra of prominences and 
of the same lines in laboratory sources 
at known temperatures. In laboratory spec- 
tra the widths of the hydrogen and calcium 
lines agree with their theoretical widths 
if it is assumed that the measurements 
include intensities greater than 8 per cent 
of the maximum. In the spectrum of a 
quiescent prominence, Ha and H$ show 
similar agreement with the theoretical 
width if a temperature of about 5700 ° K 



is assumed. No suitable quiescent promi- 
nence has been available for H and K, 
but measures on active prominences show 
widths much greater than the theoretical, 
the width in the streamers of one active 
prominence being three times that calcu- 
lated. Random group velocities at right 
angles to the streamers not exceeding 
7 km/sec would satisfy the observed line 
widths. 

Ultraviolet Solar Spectrum 

A concave-grating spectrograph and the 
equipment at the Hale Solar Laboratory 
have been utilized by Babcock in a variety 
of solar investigations. Among these is a 
study of the spectrum of the disk, spots, 
and chromosphere in the region A3250 to 
the ultraviolet limit. Numerous faint lines 
not recorded by Rowland have been ob- 
served, and a study has been made of 
the intensities of some of the strong lines 
near A3000 for comparison with their mul- 
tiplet relations. A special type of polarizer 
has proved useful in avoiding the effects 
of scattered light in the spectrograph. 

Some drift-curves across the solar disk 
at 200-angstrom intervals between A4300 
and A3000 have been obtained by Pettit 
with a 21 -foot grating spectrograph and 
quartz monochromator. A photoelectric 
amplifier and galvanometer formed the re- 
cording device. The curves show a definite 
change in the amount of limb darkening 
in the 200-angstrom intervals. 

Infrared Solar Spectrum 

The manuscript of the table of solar-spec- 
trum lines in the region AA6600-13500, in 
preparation by Babcock and Mrs. Sitterly 
with the assistance of Mrs. Coffeen, is now 
at Princeton, and the text is being com- 
pleted. Identifications are being made 
through comparisons of disk and spot spec- 
tra and through structural analysis of 



MOUNT WILSON OBSERVATORY 



laboratory lines. About one-half of the 
7500 lines are known to be telluric and 
about one-quarter of solar origin. Over 
60 per cent of the known solar lines have 
been identified, and most of these have 
been assigned to multiplets. A very weak 
band due to atmospheric oxygen has been 
discovered near A10700. 

A slight systematic difference, amount- 
ing to about 0.01 wave number, has ap- 
peared in the region AA7000-7700 between 
the wave-length scale of these lines and 
that of the Allegheny Observatory. Al- 
though too small to affect the interpreta- 
tion of the results, it is now under in- 



vestigation. 



Solar Rotation 

Two studies of the rotation of the sun 
are in progress, one by Babcock, who has 
used the spectroscopic method, and one by 
Nicholson and Miss Ware, who have meas- 
ured the motions of sunspots. 

Babcock has combined a Lummer plate 
with a concave-grating spectrograph in 
observations of 7 lines in the green region 
of the spectrum. The material used is 
equivalent to about 100 ordinary grating 
spectrograms. The data give an equa- 
torial rotational velocity close to that found 
by Adams with a grating spectrograph in 
1908, and definitely higher than most of 
the values which have been announced 
since that time. Observations in progress 
include points well in on the solar radius, 
since the method is highly sensitive and 
the effects of scattered light can be elimi- 
nated by this means. 

In their measurements Nicholson and 
Miss Ware have used material extending 
over four sunspot cycles. The observa- 
tions have been limited to single unipolar 
spots in an attempt to eliminate the effect 
of the forward motion of the preceding 
spots of bipolar groups due to gradual 



separation of the preceding and following 
members. The angular rotation is found 
to be o?o5 less per day than that previ- 
ously derived at the Greenwich Observa- 
tory. The variation with latitude is essen- 
tially the same as that found at Green- 
wich. 

Referred to a photosphere rotating at 
this slower rate, the preceding spot of a 
bipolar group moves forward as the group 
lengthens. After the following member of 
the group disappears, however, the pre- 
ceding spot stops but does not return to- 
ward its original position as it does when 
referred to a faster-rotating photosphere. 

General Magnetic Field of the Sun 

Babcock has adapted the Lummer plate 
and accessories, previously used with the 
red lines A6173 and A6302, for measure- 
ments of the general magnetic field with 
the lines A5250 and A5329. Reductions are 
now in progress on 80 spectrograms which 
include these lines. 

The H and K Lines and Magnetic 
Storms 

Although there are good theoretical 
reasons for believing that terrestrial mag- 
netic storms are caused by streams of 
charged particles ejected from active solar 
regions, so far no observational evidence 
has been obtained of the presence of such 
streams. To test the suggestion made by 
Chapman that a cloud of charged particles 
moving earthward might be detected 
through faint absorption lines on the violet 
side of the solar lines, Richardson has 
compared photographs of the H and K 
lines taken during a magnetic storm with 
similar photographs at a period of mag- 
netic calm. Observations were obtained 
with the Snow telescope during the cen- 
tral period of the violent storm of Septem- 
ber 18, 1941, and on one day preceding 



10 



CARNEGIE INSTITUTION OF WASHINGTON 



as well as during the equally violent storm 
of March i, 1942. These would seem to 
be most favorable cases so far as time is 
concerned. 

Preliminary reductions of the micro- 
photometer tracings give no definite evi- 



dence of any faint components of the nor- 
mal calcium lines before and during two 
of the most violent magnetic storms of 
the present cycle. If such lines exist, they 
must have an intensity less than 5 per cent 
of that of the continuous background. 



PLANETS AND SATELLITES 



At present no reliable determination of 
the mass of the planet Pluto exists, solu- 
tions depending upon perturbations of 
the major planets having so far proved 
unsatisfactory. Richardson has made an 
attempt to determine the mass from an un- 
explained discrepancy in the time of peri- 
helion passage of Halley's comet in 1910 
as given by the highly accurate compu- 
tations of Cowell and Crommelin. 

Special perturbations were calculated 
from 1844 to 1908 at intervals of 512 days, 
on the assumption of a mass of unity for 
Pluto. Within the errors of the computa- 
tions these corrections indicated no change 



in the time of perihelion passage. Further 
calculations extended to 1975 make it 
doubtful whether Halley's comet is ever 
affected sensibly by the attraction of Pluto. 

The investigation indicates that a planet 
of mass unity moving in the plane of the 
orbit of Halley's comet at an aphelion dis- 
tance 0.1 astronomical unit greater than 
that of the comet would delay its peri- 
helion passage by 6 days. 

Several of the faint satellites of Jupiter 
have been reobserved during the year by 
Nicholson. The elements of the orbit of 
J IX have been improved and an ephem- 
eris has been calculated for opposition. 



MISCELLANEOUS STELLAR INVESTIGATIONS 



Trigonometric Parallaxes and 
Proper Motions 

The year has seen the completion of the 
500th parallax determined by van Maanen 
in his extensive program. Both reflectors 
are used, the observations being made at 
the Cassegrainian focus of the 60-inch and 
the Newtonian focus of the 100-inch tele- 
scope. Although the focal lengths are in 
the ratio of nearly 2 to 1, the probable error 
of the parallaxes with the two instruments 
is closely the same, about o'.'oo65. This 
comparison omits 27 stars which were 
observed with a rotating sector at the 100- 
inch telescope and were apparently subject 
to exceptional sources of error. 

In recent years particular attention has 
been given in the parallax program to stars 
of large proper motion and presumably 



faint luminosity. More than 130 stars with 
absolute photographic magnitudes fainter 
than -j-10 have been added by van Maa- 
nen to a list of less than two dozen such 
stars known in 1913. Parallaxes have been 
determined for 17 of the 21 stars with 
absolute magnitudes fainter than +15. 

Studies in proper motions have included 
measurements by R. E. Wilson of fields 
containing variable stars of the § Cephei 
and RR Lyrae classes, and by van Maanen 
of areas in the Hyades region and of the 
open cluster Messier 67. Two stars, out 
of nine for which Dr. Zwicky had found 
small color indices, are probable members 
of the Taurus cluster and should be white 
dwarfs. Three other faint stars have been 
found to share the motion of the cluster 
in addition to one in the region of T 



MOUNT WILSON OBSERVATORY 



II 



Tauri of photographic magnitude about 
16.5 (corresponding absolute magnitude 

+ 13-7)- 
The results found for Messier 67 are 

based upon two photographs of the cluster 

taken at the Cassegrainian focus of the 

60-inch telescope with an interval of 21 

years. An absolute motion of o'.'ooftj in 

position angle 230 is given by the 284 

stars probably belonging to the cluster. 

Extension of the Photographic Scale in 
Certain Selected Areas 

During the year final photographic mag- 
nitudes down to 20 I ?5 have been derived 
by Baade for Selected Areas 51, 71, 85, and 
89, again with the cooperation of H. 
Weaver. Selected Area 71 was included 
at the request of Dr. Shapley, who intends 
to use this area for a final check of the 
magnitude scales in the Magellanic Clouds. 
The results for seven areas will be ready 
for publication this fall. To check the 
constancy of the platinum filter, its absorp- 
tion constant was redetermined in the sum- 
mer of 1941 : (a) with a photoelectric cell 
at the 60-inch by Professor Stebbins, and 
(b) from plates of the Polar Sequence. 
The new absorption constant agrees within 
less than o'Poi with the older value ob- 
tained in 1937. 

Effective Wave Lengths and Color 
Temperatures 

With the assistance of Miss Joyner, 
Seares has continued his discussion of the 
colors of stars provided by the Mount Wil- 
son Polar Catalogue. An important pre- 
liminary was the determination of mean 
effective wave lengths as a function of 
temperature for the photographic and the 
photovisual magnitudes of the interna- 
tional system. It thus became possible to 
compute the differential corrections for 
atmospheric extinction depending on stel- 



lar temperature and to obtain finally the 
relation between spectral type and color 
index for zero air mass. This relation is 
also fully corrected for space absorption. 
The mean color excess as a function of 
distance caused by the absorption in the 
polar region was found directly from the 
observational data. The differential ab- 
sorption depending on temperature was 
computed on the assumption that the 
absorption varies inversely as the wave 
length. Incidentally, it was shown that for 
such calculations the direct substitution 
of the effective wave length into the ab- 
sorption formula gives the same result 
for the total photographic or photovisual 
absorption as the complete integration over 
the wave-length interval. 

An important application of the effective 
wave lengths is the calculation of theo- 
retical color indices (international system) 
for black-body radiators of different tem- 
peratures. Comparison of these results 
with the spectrum-color relation then gave 
color temperatures for the different spec- 
tral types. With type A5 set at 11000 to 
fix the zero point, the result for gKo is 
4150 °. Similar calculations based on the 
photoelectric color indices of Stebbins and 
his associates give 3750 °. The mean errors 
are only a fifth of the 400 ° discrepancy, 
which in part at least seems to be real and 
attributable probably to departures from 
black-body radiation in the stars. 

Photoelectric Measures of Stars 

Stebbins and Whitford have continued 
the measures of stars with a photoelectric 
cell and filters which isolate six spectral 
regions from 3500 to 10000 A. The small 
deviations from the i/A law of interstellar 
absorption, derived from reddened B stars, 
are found to be the same for stars in widely 
separated parts of the sky, showing that 
the nature of the dust in space is much 
the same everywhere. 



12 



CARNEGIE INSTITUTION OF WASHINGTON 



Measures of the typical variable star 5 
Cephei give light-curves in six colors which 
provide new material for a theoretical dis- 
cussion of the cause of this class of stellar 
variation. The amplitude of variation at 
3500 A is four times the amplitude at 
10000 A, and there are other significant 
differences in the curves for different wave 
lengths. 

Absolute Magnitudes of Stars 

From a study of the mean absolute mag- 
nitudes of long-period variables based upon 
radial velocities and proper motions, R. E. 
Wilson and Merrill have found that the 
luminosities of these stars are related to 
the period of light-variation. A period- 
luminosity curve is obtained in which M 
reaches a maximum of — 2.7 for periods 
around 175 days, falling to — 2.2 at 150 
days and -\-o.6 at 450 days. 

The relationship has been used to study 
the total motions of these stars. The mean 
speed is high, 74 km/sec, and the veloci- 
ties exhibit the characteristics of the mo- 
tions of high-velocity stars of other classes. 
The apices of motion lie predominantly 
in that half of the sky opposite to the 
apex of the solar motion and to the direc- 
tion of galactic rotation. The preferential 
motion is in the same direction as that of 
stars in general, but for stars with the 
higher speeds this shifts to a direction 



nearly radial with respect to the galaxy. 
The motions of the long-period variables 
are explained reasonably on the hypothesis 
of galactic rotation. 

A similar investigation by R. E. Wilson 
of the mean absolute magnitudes of ir- 
regular variables of type M gives a value 
M= — 1.1, essentially the same as that 
found for the long-period variables. About 
10 per cent of the stars are supergiants, 
for which M~ — 3.4; the remainder are 
ordinary giants with M= — 0.9. No cor- 
relations appear to exist with spectral type, 
general order of period, or character of 
light-variation. Excellent agreement is 
found with the values derived by Joy 
from spectroscopic criteria. 

The average space motion of the irregu- 
lar variables, 54 km/sec, is about midway 
between that of nonvariable giants of type 
M and that of the long-period variables; 
and the group motion, V = — 28.1 km/ 
sec, shows somewhat similar behavior. In 
their kinematic properties the irregular 
variables seem to be closely related to the 
long-period variables, but in their physical 
properties the relationship to nonvariable 
stars of the same spectral type seems to be 
more prominent. 

Stromberg has now extended to giant 
stars of all spectral types from F to M 
his studies of the systematic corrections 
to be applied to spectroscopic absolute 
magnitudes. 



STELLAR SPECTROSCOPY 



The stellar spectroscopic equipment has 
remained without important changes or 
additions throughout the year. The two- 
prism spectrograph with collimating mir- 
ror, described in last year's report, has 
been used extensively at the 100-inch tele- 
scope and has proved most useful. Cam- 
eras ranging from 18 to 1.3 inches in 
focal length, including two of the Schmidt 



type, provide for the study of spectra of 
stars as faint as photographic magnitude 
16, as well as for observations of extra- 
galactic nebulae. 

Increases in the sensitiveness of photo- 
graphic emulsions, especially some of those 
developed for astronomical work by Dr. 
Mees, of the Eastman Kodak Company, 
have added greatly to the efficiency of the 



MOUNT WILSON OBSERVATORY 



J 3 



spectrographic instruments. Of particular 
value for the coude spectrograph have been 
the 1033-0 plates, which through their 
remarkable sensitivity to blue and violet 
light have brought within the range of 
observation stars nearly a magnitude 
fainter than those observed previously. 

About 1500 spectrograms have been ob- 
tained with the various instruments dur- 
ing the year. 

Radial Velocities 

Observations of radial velocity have been 
made of many stars under study primarily 
for statistical purposes, such as those in 
the Selected Areas by Stromberg and 
Christie, in the Taurus group by R. E. 
Wilson, and in the general radial-velocity 
program by several observers. Only 20 
stars in the Selected Area program are still 
unobserved. Special classes of stars whose 
physical characteristics are being investi- 
gated have also been observed for radial 
velocity. These include irregular M-type 
variables and some eclipsing variables ob- 
served by Joy, stars of types N and R 
observed by Sanford, and numerous in- 
dividual stars of especial interest. The dif- 
ferences in displacement shown by differ- 
ent lines have been studied by Merrill in 
stars of early type with emission lines. 
Five stars of type F with bright hydrogen 
lines have been discovered, in one of which, 
HD 59771, the measures show a rapidly 
expanding hydrogen atmosphere. This is 
most exceptional for stars with a relatively 
cool photosphere, and suggests an analogy 
with the rapid motions of prominences 
above the sun's reversing layer. 

Determinations of the orbits of four 
spectroscopic binaries, including the com- 
panion of Rigel, have been completed by 
Sanford. For Rigel B, spectrograms of dis- 
persion 10 A/mm, taken with the 32-inch 
coude spectrograph, have been used to a 
large extent. 



Three new spectroscopic binaries of the 
Wolf-Rayet type of spectrum have been 
discovered by O. C. Wilson. One eclipsing 
binary of this type, HD 193576, has been 
the subject of an extensive study, measures 
of the total absorption of the Hy line of 
the B-type component before and after 
eclipse being combined with photometric 
data from the light-curve to derive the 
relative dimensions of the two stars. The 
Wolf-Rayet star is found to be the larger. 
Wilson then investigated the validity of 
the hypothesis of an expanding envelope 
as the source of the emission bands in the 
spectrum. On the assumption of this hy- 
pothesis, one of two phenomena should 
be observable : (a) If the envelope is small, 
the part behind the eclipsing star should 
be occulted and the emission bands should 
be shifted toward the violet; (b) if the en- 
velope is large, there should be a time lag 
between the observed and the predicted 
eclipses. Neither effect has been observed, 
and the evidence seems to throw consider- 
able doubt upon the usual explanation of 
the origin of the emission bands. 

The velocity-curve of the star HD 142983 
(48 Librae), which has been rising ever 
since a remarkable minimum in 1937, re- 
cently reversed its upward trend, accord- 
ing to observations by Merrill and San- 
ford, a maximum apparently having oc- 
curred in 1 941. The future course of the 
displacements shown by the various lines 
will be followed with interest. 

Humason and Joy have continued ob- 
servations of faint dwarf stars for radial 
velocity and spectral type. Most of them 
are of type M, bright hydrogen lines and 
bright H and K being frequent. A list 
of 17 M-type dwarf stars with hydrogen 
emission has been published. 

Variable Stars 

A study by Joy of the spectra of 118 M- 
type variables with light-curves less regular 



14 



CARNEGIE INSTITUTION OF WASHINGTON 



than those of the o Ceti class leads to the 
following conclusions: (i) The spectro- 
scopic absolute magnitudes based upon the 
1935 system show the existence of super- 
giants such as a Ononis with magnitudes 
between — 2.0 and — 4.5, but indicate that 
90 per cent of the stars are normal giants 
like the Ceti stars with a mean absolute 
magnitude of —0.9. These results are in 
remarkably good agreement with those 
calculated by R. E. Wilson from proper 
motions and radial velocities. (2) The 
supergiants show a marked galactic con- 
centration with a mean latitude of 11 °, 
but the normal giants show no concentra- 
tion. (3) Spectral types of supergiants, 
Mo to M5, are on the average earlier than 
those of the normal giants. (4) Corrected 
for solar motion, the average residual ra- 
dial velocities are 18.2 km/sec for the 
supergiants, and 26.1 km/sec for the giants. 
Stars with the shorter periods show the 
larger velocities and the greater dispersion 
in velocity. (5) The mean displacement 
to the violet of the bright lines with re- 
spect to the absorption lines in the spectra 
of 17 stars showing faint emission lines 
at certain phases is 8.9 km/sec. This is in 
agreement with the results for stars of 
the Ceti class. (6) For a given spectral 
type the periods of the irregular variables 
are much shorter than those of the Ceti 
stars. They may be higher harmonics of 
the fundamental periods. 

Joy has also continued his observations 
of stars of the T Tauri class, most of which 
are situated in obscured regions of the 
Milky Way, sometimes associated with 
nebulosity. The absorption spectra are of 
types F and G and indicate low luminosity. 
The emission spectra are unique in show- 
ing bright lines of neutral elements such 
as iron, magnesium, and calcium, in addi- 
tion to hydrogen and many ionized ele- 
ments. Helium is weak or absent, and the 
forbidden nebular lines are not present. 



The H and K lines of ionized calcium are 
exceedingly strong. In many respects these 
emission spectra resemble that of the sun's 
chromosphere. 

Numerous individual variable stars of 
exceptional spectroscopic interest have been 
under observation during the year. Of 
these BD -[- 1 1 ° 4673 (AG Pegasi) is one 
of the most remarkable. In a fourth report 
upon this star Merrill finds that the 800- 
day cycle in the displacements of the hy- 
drogen lines has continued but the ampli- 
tude has diminished since 1928. Progres- 
sive changes in the spectrum since 1915 
include strengthening and widening of 
bright lines of H and He 1; increasing dis- 
placements toward the violet of dark lines, 
indicating faster outward motions from 
the star; and a general increase in the 
ionization of the atmosphere as shown by 
the lines of He 1, He 11, Fe 11, Fe in, N 11, 
N in, Si in, and Si iv. The dark bands of 
TiO have gradually grown stronger until 
their intensities are approximately equal 
to those in type Mi. Thus BD -|- 1 1 ° 4673 
enters the small group of stars with "com- 
bination" spectra. If we assume an ex- 
panding atmosphere, certain facts suggest 
that the velocities of atoms increase as they 
travel outward and that the degree of 
ionization also increases. 

Bands in the spectrum of the N-type 
variable U Cygni which are especially 
strong near minimum of light (AA6185, 
621 1), previously ascribed to the Ca 2 mole- 
cule, have been identified by Sanford as 
due to the CaCl molecule. Thus chlorine 
seems to be a constituent of the atmosphere 
of this star. These bands also appear in 
the spectra of other cool stars of type N. 

Joy has found the irregular variable 
UZ Tauri, previously classified as an old 
nova, to be a double star with a separa- 
tion of about 3'.'5. Both components show 
bright H and K and hydrogen lines and 
appear to be dwarf Me stars. 



MOUNT WILSON OBSERVATORY 



15 



An interesting observation by Joy of 
RW Tauri at time of total eclipse indicates 
that the brighter B9 star is surrounded 
by a gaseous shell or ring giving emission 
lines of H, Mg 11, Ca 11, and Fe 11. These 
lines are displaced 350 km/sec and point 
to a rapid rate of rotation with a period 
much shorter than the period of orbital 
revolution. A twelfth-magnitude compan- 
ion was discovered at a distance of about 
1" from the eclipsing pair. 

Joy has also continued his observations of 
variables of the RV Tauri, SS Cygni, and 
R Coronae types, and of high-luminosity 
variables in globular clusters. 

Miscellaneous Observations 

As a result of the survey of early-type 
stars with the 10-inch photographic tele- 
scope and objective prism, based upon the 
Ha line, the discovery of 119 bright-line 
stars of types B and A has been announced 
by Merrill, Miss Burwell, and W. C. 
Miller. For 78 of these stars the types and 
other spectroscopic data have been deter- 
mined from slit spectrograms. This in- 
vestigation also led to the discovery of the 
bright-line F-type stars to which reference 
has already been made. 

A list of 33 recently discovered stars of 
types N and S has been published during 
the year by Merrill, Sanford, and Miss Bur- 
well. Merrill has also studied stars with 
anomalous spectra combining TiO bands 
and bright lines which require high ex- 
citation, and a few early-type stars with 
spectra resembling those of c stars but 
believed to be of relatively low absolute 
magnitude. 

Humason has continued his investiga- 
tion of old novae with a larger dispersion 
(220 A/mm) than has heretofore been 
used. Nine of these objects have been re- 
observed and confirm the early observa- 
tions, which showed that in their present 



state the old novae are decidedly blue, 
with spectra corresponding to that of the 
O- or early B-type stars. 

Observations of faint blue stars found 
by Dr. Zwicky at Palomar have been con- 
tinued by Humason. In addition, several 
stars which Zwicky found to have a bright 
Ha on objective-prism plates have been in- 
vestigated. One of these is most probably 
a faint galactic nova, and the others may 
be bright-line variable stars. 

Interstellar Lines 

The 114-inch Schmidt camera of the 
coude spectrograph has been used exten- 
sively during the year by Adams in ob- 
servations of interstellar lines. The high 
resolving power of the instrument has been 
particularly valuable in showing the com- 
posite structure of the H and K lines in 
many stars, and in making visible on plates 
of high sensitivity but coarse grain the 
other faint lines discovered in recent years. 
The presence of interstellar lines of neu- 
tral iron has been established by observa- 
tions of the two ground-state lines at 
A3720 and A3860, which are extremely faint. 

The identification by Herzberg of the 
three lines at AA3745, 3957, and 4232 with 
lines arising from the CH 11 molecule com- 
pletes, with the possible exception of one 
or two doubtful lines, the identification of 
all the sharp interstellar lines so far dis- 
covered. It also provides, through inter- 
comparison of the intensities of A4300 CH 1 
and A4232 CH 11, a means of determining 
the numbers of CH molecules in each state 
along the line of sight in interstellar space. 
The observations already made show 
marked differences in the relative intensi- 
ties of these lines. For example, in the 
spectra of the two stars £ Persei and £ 
Persei, which lie but a few degrees apart 
in the sky and have H and K lines of the 



i6 



CARNEGIE INSTITUTION OE WASHINGTON 



same order of intensity, the ratios of A4300 
to A4232 are about 5 : 1 and 1 : 5, respec- 
tively. 

Under the high resolution of the coude 
spectrograms, complex structure of the H 
and K lines is found to be the rule rather 
than the exception. Of the 43 stars in- 
vestigated, 10 show single interstellar lines 
and the remaining 33 double or multiple 
lines. Complex lines are especially nu- 
merous in the stars observed in Orion, 
Ophiuchus, Sagittarius, and Cygnus, and 
single lines in Perseus and Scorpius. Since 
the components of the complex lines are 
doubtless due to individual gaseous clouds 
and are separated by the relative motions 
of these clouds in the line of sight, meas- 



urements of radial velocity afford a means 
of identifying the different clouds and de- 
termining their extent. 

Some individual stars of especial interest 
are: u Sagittarii, in which H and K are 
well marked double lines with the compo- 
nents separated by 0.22 A; u Sagittarii, 
with triple and possibly quadruple com- 
ponents of very unequal intensities; and 
P Cygni, with two definite components 
not fully resolved. Three lines due to CH 
11 and one due to CH 1 are present in the 
spectrum of P Cygni; and the line A4232 
of CH 11 is visible in u Sagittarii, the only 
star of comparatively advanced type of 
spectrum in which this line has been ob- 
served. 



GALACTIC NEBULAE 



The principal results in the field of galac- 
tic nebulae include the definitive inter- 
pretation of the spectrum of the Crab 
nebula (supernova of 1054) by Minkowski, 
further information concerning the rem- 
nant of Kepler's supernova of 1604 by 
Baade and Minkowski, and the detection 
of the emerging structure in the expand- 
ing shell around Nova Herculis (1934) by 
Baade. In addition, spectrographic data 
have been obtained on the filamentary 
nebula in Cygnus and the inner nebulosity 
around R Aquarii by Humason, and the 
distribution of light along a diameter of 
the typical planetary NGC 6572 has been 
investigated spectrophotometrically by Sey- 
fert. 

Expanding Shell around Nova Herculis 
(1934) 
Direct photographs obtained by Baade in 
the spring of 1942 indicate that the surface 
brightness has declined much faster dur- 
ing the past two years than can be ac- 
counted for on the assumption of constant 
total brightness and increasing size of disk. 



A star is now easily seen at the center, 
and the true structure of the shell, ap- 
parently that of an elliptical ring nebula, 
is beginning to emerge. This interpreta- 
tion of the structure is confirmed by a 
large-scale spectrum of the nebulosity ob- 
tained on June 8, 1942, by Humason and 
Baade. The Ni and N2 lines appear as 
elliptical rings such as would be expected 
from an expanding shell of finite thickness. 

Spectrographic Study of the Crab 
Nebula Remnant of the Super- 
nova of 1054 

The spectrographic study of the Crab 
nebula has been concluded by Minkowski 
after an extension of the observations into 
the red and the ultraviolet. The line emis- 
sion spectrum of the filaments contains 
lines of H, He 1, He 11, [N 11], [0 1], 
[0 11], [O m], and [S 11]. The H lines 
are relatively faint, probably owing to low 
abundance of hydrogen. The high in- 
tensity of the filaments in the red is due to 
the \_N 11] and the unusually intense 
[S 11] lines. The spectrum of the diffuse 



MOUNT WILSON OBSERVATORY 



17 



nebulosity forming the main mass is con- 
tinuous except for a faint discontinuity 
at the Balmer limit. Practically the entire 
energy emitted by the nebula is contained 
in the continuous spectrum, whose in- 
tensity distribution deviates from that of 
a black body, the color temperature being 
about 8400 at A4500, and 6700 at A6000. 

In the absence of absorption in the 
nebula, the continuous spectrum cannot be 
due to scattering and must be a true emis- 
sion spectrum. The only physically justi- 
fied assumption is that the continuous 
spectrum is produced by free-free and free- 
bound transitions of electrons in the very 
highly ionized gas. On this assumption, 
the observed intensity distribution in the 
continuous spectrum finds a satisfactory 
explanation. The electron density of the 
diffuse mass is of the order io 3 cm -3 , the 
electron temperature of the order 50,000°, 
the mass about 15 solar masses, and the 
hydrogen abundance probably low. The 
central star has a temperature of the order 
of 500,000°, a radius of 0.020 solar radius, 
and a total luminosity of 30,000 solar units. 
These results as a whole indicate that be- 
fore their outbreak, supernovae of type I 
are massive stars of low hydrogen abun- 
dance. During the outbreak, the star 
ejects the greater part of its mass and be- 
gins to develop into a white dwarf. The 
present high temperature and high lumi- 
nosity of the central star of the Crab 
nebula indicate that this stellar remnant 
of the supernova of 1054 has not yet fin- 
ished the transformation into the degener- 
ate state. 

Nebulosity around Nova Ophiuchi 
(1604) 

Long-exposure photographs in the red, 
obtained by Baade, show that the fan- 
shaped mass he discovered last year is 
only a part of the nebulosity surrounding 



the former supernova, and that faint wisps 
are scattered over a field about 80" in di- 
ameter. Evidently the obscuration in front 
of the nebula is not only very heavy, as 
was pointed out in last year's report, but 
also quite variable over the field. 

The spectrum of the nebulosity has been 
observed in the red by Minkowski. The 
combination of a plane grating (400 lines 
per mm) with a solid Schmidt camera, 
f/0.65, giving a dispersion of 400 A/mm, 
has shown itself very useful for this pur- 
pose. The spectrum of the nebulosity con- 
sists of the lines [0 in] A5007, [O 1] A6300, 
[N 11] AA6548, 6584, Ha, and [S 11] 
A6731. The spectrum is very similar to 
that of the filaments of the Crab nebula, 
especially as regards the low intensity of 
Ha relative to the \_N 11] lines. The in- 
tensity of [O 111] A5007, however, is much 
less than in the Crab nebula. This is evi- 
dently due to heavy space reddening, and 
a color excess of about 2 magnitudes is 
suggested. The radial velocity is — 200 
km/sec at the (north following) tip of the 
fan-shaped nebulosity and probably about 
— 260 km/sec at the (south preceding) 
base. The velocity is too high to admit any 
interpretation other than that the fan- 
shaped nebulosity is part of an expanding 
nebula, the center of expansion being situ- 
ated closer to the base than to the tip. 

Distribution of Light in NGC 6572 

From a spectrophotometric study of the 
distribution of light along a diameter of 
the planetary NGC 6572, Seyfert has found 
that the luminosity gradients in the emis- 
sion lines Ni, N2, A4471, A4363, A3869, 
and the hydrogen lines are remarkably 
similar. The O 11 doublet, A3727, however, 
gives an image 20 to 30 per cent larger 
than the mean of the other monochro- 
matic images that have been investigated. 
The results are consistent with Berman's 



i8 



CARNEGIE INSTITUTION OF WASHINGTON 



earlier investigations of monochromatic trograms of faint wisps of nebulosity with- 
images of the nebula. in the great Cygnus Loop for the purpose 

of investigating expansion in the line of 

Miscellaneous sight. Humason has also obtained addi- 

Humason and Baade have succeeded in tional spectra of the inner emission nebu- 

obtaining a number of long-exposure spec- losity around the variable star R Aquarii. 

EXTRAGALACTIC NEBULAE 



The principal results in the study of ex- 
tragalactic nebulae are the completion of 
investigations of the direction of rotation 
in spirals by Hubble, and of nuclear emis- 
sion in spirals by Seyfert. In addition 
Baade has identified an eclipsing binary 
and a normal Cepheid with the unusual 
period of 146 days in IC 1613, and Hubble 
and Humason have made considerable 
progress in the observing program which 
will eventually lead to a general catalogue 
of the fundamental data furnished by neb- 
ular spectra. 

Direction of Rotation of Spirals 

Hubble has found that in 15 spirals for 
which the necessary data are available, 
the dissymmetry of obscuration combined 
with the character of the spiral pattern is 
definitely correlated with the sense of the 
spectrographic rotation. On the assump- 
tion that the tilt is indicated by the dis- 
symmetry of obscuration, all 15 nebulae 
are rotating in the same direction with re- 
spect to the spiral patterns. 

In 4 spirals, NGC 3190, 4216, 4258, and 
4527, the actual direction is determined 
by dark lanes which, because they are 
silhouetted against the nuclear bulges, un- 
ambiguously identify the nearer sides of 
the nebulae. In these nebulae, the arms 
are trailing behind the nuclear regions. 
The results are the basis for the working 
hypothesis that the arms are trailing in all 
spirals, and that the greater obscuration 
identifies the nearer side of the projected 
image of a nebula. 



Nuclear Emission in Spirals 

Seyfert has continued his investigations 
of nuclear emission in spirals with especial 
emphasis on NGC 1068, 3516, and 4151. 
The emission lines and their relative in- 
tensities in these nebulae (as well as NGC 
1275 and 4051) show a general similarity 
to the lines in the planetary NGC 7027. 
The lines are superposed on G-type con- 
tinuous spectra in which the intensity 
distributions correspond to temperatures 
of 5250 for NGC 1068 and 3516, and 
4750 ° for NGC 4151. The ratios of light 
in the emission lines to the total luminosi- 
ties (emissions plus continua) in the photo- 
graphic region are about 13, 5, and 20 per 
cent for NGC 1068, 3516, and 4151, re- 
spectively. 

The line contours in NGC 1068 fall into 
two main groups, with line widths rang- 
ing from 2400 km/sec for A3869 and A3968 
of [Ne in] to 3600 km/sec for A6717 and 
A6731 of [S 11]. The four lines Ni, N2, 
H$, and A3869 have absorption cores, and 
considerable evidence, including wave 
lengths and equivalent widths, suggests 
that the apparent central reversals may be 
due to superposed absorption lines arising 
from the G-type continuum. 

In NGC 3516, the hydrogen lines are 
extremely broad, shallow bands (> 100 
A), whereas Ni and N2 are relatively nar- 
row. In NGC 4151, the contours of the 
forbidden lines and of the cores of the 
hydrogen lines are closely similar. They 
are about 1000 km/sec wide and show pro- 



MOUNT WILSON OBSERVATORY 



19 



nounced asymmetry. The bright cores of 
the hydrogen lines Ha to Hh are super- 
posed on fainter wings, each about 7500 
km/sec wide. The spiral NGC 7469 (for 
which Dr. Mayall first reported an emis- 
sion spectrum) has hydrogen lines with 
wide wings resembling those observed in 
NGC 4151. 

Spectra of Nebulae 

Spectra of 82 nebulae, 60 of which had 
been previously unobserved, were obtained 
during the year by Hubble and Humason. 
The Mount Wilson collection now in- 
cludes spectra of 370 nebulae out of the 
total of 440 observed at all stations. Most 
of the spectra are on a small scale, but 
those of 50 nebulae are on an intermediate 
scale, and those of 4 nebulae on a suffi- 
ciently large scale (65 A/mm and larger) 
to permit the study of line contours. 



Variables in IC 1613 

Baade has obtained a spectrum of a 
Cepheid in IC 1613 with the exceptionally 
long period of 146.35 days. The star was 
near maximum (m vs =iy.^). The spec- 
tral type was K2 (based on the intensities 
of Ca Xqzzj and the Sr pair, AA4215 and 
4077) . The supergiant character of the star 
is indicated by the great strength of the 
hydrogen lines. The data remove the 
last doubts that Cepheids with periods up 
to 150 days (and perhaps 200 days) do 
occur. Periods longer than 50 days, how- 
ever, are extremely rare. 

Another interesting variable in IC 1613 
has proved to be an eclipsing binary with 
a period of 3.775 days. Both the color and 
the density (derived from the photometric 
orbit) indicate that the main component 
is an early B-type star. The absolute mag- 
nitude of the system is — 2.6. 



LABORATORY INVESTIGATIONS 



Rare-Earth Spectra 

Further studies of rare-earth spectra by 
A. S. King have dealt with gadolinium and 
dysprosium, and a beginning has been 
made upon terbium. The completion of 
the temperature classification of Gd lines 
involved additional work on the ultraviolet 
spectrum and improvement of the data for 
other regions. The final list, from A2135 
to A 1 0670, contains 5732 lines, extending 
the spectra of Gd 1 and Gd 11 to lines of 
low intensity. At wave lengths shorter 
than A2700, where very few lines had previ- 
ously been measured, the lines of Gd 111 
are prominent. The strongest of these, 
some from such low atomic levels as to 
appear in the arc spectrum, are listed. A 
comparison with the solar spectrum shows 
that many low-level lines of Gd 11, present 
in the furnace spectrum, coincide with 
unidentified solar lines. If the probability 



that these lines occur in the sun is con- 
firmed by the term analysis being made 
by Albertson and Russell, a considerable 
increase in the number of Gd solar lines 
over those identified in the Revised Row- 
land table of solar wave lengths will result. 
No evidence of Gd 1 in the sun has thus 
far been found. 

Dr. Russell has extended the analysis of 
the gadolinium arc spectrum and has de- 
rived an ionization potential of 6.16 volts. 
Further analysis is in progress. 

The spectrum of Dy has been examined 
from A3 1 50 to A6800, chief attention being 
given to the lines of Dy 11 and their classi- 
fication by means of the furnace spectrum. 
As in the case of Gd, agreement with solar 
lines is found for many of the strong low- 
level lines of Dy 11, as well as for the few 
identified in the Revised Rowland. The 
Dy spectrum has a group of very strong 



20 



CARNEGIE INSTITUTION OF WASHINGTON 



low-temperature lines in the violet which 
reverse easily in the furnace — a type un- 
usual in rare-earth spectra. The strongest 
of these lines, when not masked, are identi- 
fied in the Revised Rowland with faint 
solar lines, and, before the furnace spectra 
were available, were ascribed to Dy n. 
They are now shown to be due to Dy i, 
this being the second rare earth whose 
neutral lines have been observed in the 
sun. Those of a third element, europium, 
are found only in the sunspot spectrum. 

Calcium Oxide 

A group of green and orange bands, 
present in many red stars, and tentatively 
ascribed to calcium oxide, has been ex- 
amined in the electric furnace by A. S. 
King. The oxide origin was confirmed 
when the bands appeared with high in- 
tensity in the furnace spectrum of calcium 
with oxygen passing over the metal, but 
were absent when calcium was vaporized 
in vacuum at the same temperature. 

Abundance of Iron in the Sun 

A value for the abundance of neutral 
iron atoms in the sun has been derived 
by R. B. King. Solar equivalent widths 
from Allen's tables and the Utrecht Atlas 
in conjunction with absolute /-values ob- 
tained recently in the laboratory were uti- 
lized. Twenty-three strong iron lines, on 
the square root, or damping, portion of the 
solar curve of growth, for which absolute 
/-values are available were used. A damp- 
ing constant of 10 times the classic value 
and an excitation temperature of 4400 ° 
were assumed in making the computations. 
The total number of neutral iron atoms 
per square centimeter was found to be 

4-3 X 10 18 . 

The cause for small but apparently real 
systematic differences between the results 
for abundance given by lines of different 



multiplets is as yet obscure, since several 
factors may be involved. Laboratory in- 
vestigations by Minkowski and R. B. King 
have shown that the differences cannot be 
due to pressure broadening alone, since no 
similar differences are found for these 
lines broadened by atmospheric pressure at 
2890 ° in the furnace. The suggestion is 
made that under solar conditions broaden- 
ing due to "natural" widths of the lines is 
not negligible. An extension of the labora- 
tory /-values for Fe to lines of higher level 
which has been in progress may aid in 
settling this question. 

Relative /-values 

The work on relative /-values for V 1, 
Ni 1, and the higher-level lines of Fe 1 
has been continued. In vanadium almost 
all lines of temperature classes i-iv are ob- 
served in absorption at a furnace tempera- 
ture of 3000 ° C. For the present, however, 
it has been decided to limit the observa- 
tions to lines of classes i-iii in the astro- 
physical region of the spectrum. Measure- 
ments on a large part of these lines are 
complete. 

Ruling Machines 



Some minute errors of the accidental 
type in the smaller ruling machine have 
been traced by Babcock and Prall to the 
thrust bearing of the screw. To bring these 
under control the plan has been devised of 
subjecting the bearing to a definite, con- 
stant load, large as compared with the 
operating stresses, and applied directly to 
the screw itself. The mechanical parts 
needed to test this method are nearly 
completed. 

The larger machine, with its capacity for 
ruling gratings of very great size, for 
example metallic gratings from which 
replicas can be made for use as objective 



MOUNT WILSON OBSERVATORY 



21 



gratings, has been modified to admit of 
spacings between 600 and 1000 to the inch 
and lines up to 18 inches long. Because of 
the coarse spacing, remarkable concen- 
tration of the diffracted light is possible. 
Numerous small rulings of excellent qual- 
ity have been made, and the problem of 



producing a large ruling surface with 
suitable properties is being investigated. 
Evaporated and electroplated metallic 
films, alloys of soft metals, wax, and plas- 
tics have been tested, with the result thus 
far that a lead-tin alloy seems to be best 
adapted for the purpose. 



CONSTRUCTION AND MAINTENANCE 



Design and Instrument Shop 

About 70 per cent of the time of the 
department of engineering and design dur- 
ing the past year and 55 per cent of the 
time of the instrument shop have been 
devoted to the design and construction of 
apparatus and instruments, usually experi- 
mental, for military purposes. The instru- 
ment and optical shops have cooperated 
closely in this work. 

The mounting of the new 10-inch photo- 
visual telescope has been completed, and 
this instrument should soon be in opera- 
tion. Other equipment which has been 
designed and partially constructed includes 
a small prime-focus spectrograph, a projec- 
tion measuring machine, and the auto- 
matic microphotometer planned by Whit- 
ford and O. C. Wilson. 

E. C. Nichols, assisted by H. S. Kinney, 
has continued in charge of the department 
of design, and Albert Mclntire of the in- 
strument shop. 

Optical Shop 

A very large part of the work of the 
optical shop, which has been expanded to 
include a part of an adjoining building, 
has consisted in the development of meth- 
ods of manufacture and testing of optics 



for military use. D. O. Hendrix has de- 
voted his entire time to this work, and 
John Dalton has been completing the fig- 
uring of the three-component objective 
of the 10-inch photovisual telescope. 

Buildings and Grounds 

Both on Mount Wilson and in Pasadena, 
construction has been limited to repairs 
and general maintenance except for such 
changes as have been necessitated by the 
war projects in progress. Several buildings 
have been repainted and the paving of the 
road extending through the Observatory 
property on Mount Wilson has been com- 
pleted. A wire fence, enclosing the labora- 
tory, powerhouse, and living quarters on 
the southern side of the mountain top but 
allowing the public access to the main 
telescope buildings, has added greatly to 
the comfort of the observers and others 
living on the mountain. This work has 
been in charge of A. N. Beebe, superin- 
tendent of construction. 

A large part of the telephone line, in- 
cluding many poles, has been replaced dur- 
ing the year by Sidney Jones, engineer, 
and Kenneth de Huff, assistant engineer. 
Connections with this line have been af- 
forded to the U. S. Signal Corps and other 
military observers on Mount Wilson. 



THE LIBRARY 



The library now contains 14,857 volumes, 
together with large collections of pam- 
phlets and lantern slides. During the year 



298 volumes were added, 56 by purchase, 
43 Dv gift, and 199 by binding. From the 
200 observatories and research institutions 



22 



CARNEGIE INSTITUTION OF WASHINGTON 



whose publications generally come to the of periodicals received during the year has 
Observatory, very little material has been dropped from 140 to 87; 29 of these are 
received because of the war. The number gifts or exchanges. 



BIBLIOGRAPHY 



Adams, Walter S. Survey of the year's work at 
Mount Wilson. Pubs. A. S. P., vol. 53, pp. 
315-322 (i94i) ; 

Identificacion de las rayas y bandas in- 

terestelares. Read at Congreso Interameri- 
cano de Astrofisica, Observatorio Astrofisico 
Nacional de Tonanzintla, Mexico (1942). 
See Dunham, Theodore, Jr. 



Anderson, John A. The Astrophysical Observa- 
tory of the California Institute of Technology. 
Jour. R. A. S. Canada, vol. 36, pp. 177-200 
(1942). 

Beach, Alice. The zodiacal light. A. S. P. 
Leaflet, No. 155. 8 pp. (1942). 

If you want to be an astronomer. Nature 

Mag., vol. 35, pp. 79-80, 108 (1942). 

Burwell, Cora G., and Henrietta Swope. A 
faint nova in Ophiuchus (July 1940). Pubs. 
A. S. P., vol. 53, p. 343 (1941). 

See Merrill, Paul W. 

Christie, William H. The great Siberian 

meteorite of 1908. Griffith Observer, vol. 6, 

pp. 38-47 (1942). 
Connor, Elizabeth. Sir Isaac Newton, the 

pioneer of astrophysics. A. S. P. Leaflet, No. 

158. 8 pp. (1942). 

The new observatory on Palomar Moun- 
tain. Western Jour. Education, vol. 48, pp. 
10-11 (1942). 

Dunham, Theodore, Jr., and Walter S. Adams. 

Iron as an interstellar gas. Pubs. A. S. P., 

vol. 53, pp. 341-342 (1941). 
Hubble, Edwin. The problem of the expanding 

universe. 20th annual Sigma Xi lecture, 

Dallas (1941); Amer. Scientist, vol. 30, pp. 

99-115 (1942); (abstract) Science, vol. 95, 

pp. 212-215 (1942). 
Humason, M. L. Recent advances in astronomical 

photography. A. S. P. Leaflet, No. 154. 6 pp. 

(1941). 

See Joy, Alfred H.; Wilson, Ralph E. 

Joy, Alfred H. A spectrographic study of the 

eclipsing variable star, WW Draconis. Astro- 
phys. Jour., vol. 94, pp. 407-411 (1941); 
Mt. W. Contr., No. 654. 

Spectral criteria in the classification of 

variable stars. Read at Dallas meeting, 
A. A. A. S., section D (1941) ; Pubs. A. S. P., 
vol. 54, pp. 15-18 (1942). 



— The "nova-like" variable UZ Tauri. 
Pubs. A. S. P., vol. 54, pp. 33-35 (1942). 

— Observations of RW Tauri at minimum 
light. Pubs. A. S. P., vol. 54, pp. 35-37 
(1942). 

— and M. L. Humason. Dwarf stars with 



emission lines of hydrogen and calcium. 

Pubs. A. S. P., vol. 53, p. 296 (1941). 
Karr, Earl. See Sanford, Roscoe F. 
King, Arthur S. Notes on the work of the 

Society during 1941. Pubs. A. S. P., vol. 54, 

PP- 5-7 (1942). 

Calcium oxide and chloride bands in the 

electric furnace. Pubs. A. S. P., vol. 54, 
PP- 157-158 (1942). 

King, Robert B. Absolute /-values for lines of 
Fe 1. Astrophys. Jour., vol. 95, pp. 78-81 
(1942) ; Mt. W. Contr., No. 655. 

Abundance of iron in the sun. Astrophys. 

Jour., vol. 95, pp. 82-87 (1942); Mt. W. 
Contr., No. 656. 

Merrill, Paul W. The spectrum of BD + 11 
4673 during the years 1937-1941. Astrophys. 
Jour., vol. 95, pp. 386-401 (1942); Mt. W. 
Contr., No. 659. 

Special problems of Be spectra. Read at 

Symposium on Astronomical Spectra, Yerkes 
Observatory (1941); (partial abstract) As- 
trophys. Jour., vol. 95, pp. 268-269 (1942). 

The spectrum of RU Lupi. Pubs. A. S. P., 

vol. 53, pp. 342-343 (1941). 

Two small planetary nebulae. Pubs. 

A. S. P., vol. 54, p. 107 (1942). 

Five bright-line stars of class F. Pubs. 

A. S. P., vol. 54, pp. 155-156 (1942). 

The spectrum of BF Cygni. Read at 

Yerkes meeting, A. A. S. (1941); (abstract) 
Pubs. A. A. S., vol. 10, p. 168 (1942). 

Annie Jump Cannon. Monthly Notices 

R. A. S., vol. 102, pp. 74-76 (1942). 

Cora G. Burwell, and William C. 

Miller. Discovery and observations of stars 
of class Be. Third paper. Astrophys. Jour., 
vol. 96, pp. 15-19 (1942); Mt. W. Contr., 
No. 664. 

Roscoe F. Sanford, and Cora G. Bur- 



well. Additional stars of classes N and S — 
second list. Pubs. A. S. P., vol. 54, pp. 107- 
109 (1942). 



MOUNT WILSON OBSERVATORY 



23 



Merrill, Paul W. See Wilson, Ralph E. 

Miller, William C. See Merrill, Paul W. 

Minkowski, R. Spectra of planetary nebulae of 
low surface brightness. Astrophys. Jour., 
vol. 95, pp. 243-247 (1942); Mt. W. Contr., 
No. 657. 

Curvature of the lines in plane-grating 

spectra. Astrophys. Jour., vol. 96, pp. 306-308 
(1942). 

Mulders, Elizabeth Sternberg. See Nicholson, 

Seth B. 
Nicholson, Seth B. Ephemeris of J IX. Pubs. 

A. S. P., vol. 53, p. 292 (1941). 

Sunspots and magnetism. Alexander F. 

Morrison lecture (Oct. 1941); Pubs. A. S. P., 
vol. 53, pp. 305-314 (1941). 

(Review) Annals of the Astrophysical 

Observatory of the Smithsonian Institution, 
vol. 6. Pubs. A. S. P., vol. 54, pp. 167-169 
(1942). 

The satellites of Jupiter. Jour. R. A. S. 

Canada, vol. 35, pp. 415-420 (1941). 

and Elizabeth Sternberg Mulders. 

Sunspot activity during 1941. Pubs. A. S. P., 
vol. 54, pp. 8-10 (1942). 

Solar and magnetic data, April, 



1941, to March, 1942, Mount Wilson Ob- 
servatory. Terr. Mag., vol. 46, pp. 364-366, 
471-472 (1941); vol. 47, pp. 81-82, 174-176 
6942). 

Pettit, Edison. The rotation of a tornado promi- 
nence. Pubs. A. S. P., vol. 53, pp. 289-290 
(1941). 

Determining the speed of a camera 

shutter by a thermoelectric method. Pubs. 
A. S. P., vol. 54, pp. 37-41 (1942). 

The use of the interference polarizing 



monochromator. Pubs. A. S. P., vol. 54, 
pp. 41-43 (1942). 
Richardson, Robert S. (Review) Geomagnetism, 
by Sydney Chapman and Julius Bartels. 
Astrophys. Jour., vol. 94, pp. 553-554 (1941). 

An attempt to determine the mass of 

Pluto from its disturbing effect on Halley's 
comet. Pubs. A. S. P., vol. 54, pp. 19-23 
(1942). 

The unofficial side of astronomy. A. S. P. 

Leaflet, No. 151. 8 pp. (1941). 

The not-so-distant celestial bodies. A. S. 

P. Leaflet, No. 157. 8 pp. (1942). 

An attempt to identify the solar M- 

regions. Trans. Amer. Geophys. Union, Re- 
ports of 22d annual meeting, pt. 2, pp. 454- 
456 (1941). 



Russell, Henry Norris. Spectral structure and 
ionization potential of gadolinium 1. As- 
trophys. Jour., vol. 96, pp. 11-14 (1942); 
Mt. W. Contr., No. 663. 

Sanford, Roscoe F. The spectrographic orbit of 
the companion to Rigel. Astrophys. Jour., 
vol. 95, pp. 421-424 (1942); Mt. W. Contr., 
No. 661. 

The spectrographic orbit of 42 Capri- 

corni. Astrophys. Jour., vol. 95, pp. 425-427 
(1942); Mt. W. Contr., No. 662. 

Spectral classification of five red variables. 

Pubs. A. S. P., vol. 53, pp. 290-291 (1941). 

Radial velocities of the secondary com- 
ponents of [3GC 8287 and (3GC 10437. Pubs. 
A. S. P., vol. 53, pp. 291-292 (1941). 

Evidence of chlorine in U Cygni. Pubs. 

A. S. P., vol. 54, pp. 158-159 (1942). 

Early astronomy in South America. 

A. S. P. Leaflet, No. 159. 8 pp. (1942). 

and Earl Karr. The spectroscopic bi- 
naries Z1669A and Z1669B. Pubs. A. S. P., 
vol. 54, p. 154 (1942). 

See Merrill, Paul W. 



Seares, Frederick H. Absorption by the dust 
of space. Griffith Observer, vol. 5, pp. 134- 
140 (1941). 

Seyfert, Carl K. Ships and stars. A. S. P. 
Leaflet, No. 160. 8 pp. (1942). 

Stromberg, Gustaf. The physical and the non- 
physical worlds and their intermediate ele- 
ments. Sci. Monthly, vol. 54, pp. 71-80 
(1942). 

Mind and matter. Jour. Amer. Soc. for 

Psychical Research, vol. 36, pp. 113-121 
(1942). 

Summary of Mount Wilson magnetic observa- 
tions of sunspots for July, 1941, to May, 1942. 
Pubs. A. S. P., vol. 53, pp. 297-299, 344-346 
(1941); vol. 54, pp. 43-45; iio-iii, 161-164 
(1942)- 

Swope, Henrietta. See Burwell, Cora G. 

van Maanen, Adriaan. The photographic de- 
termination of stellar parallaxes with the 60- 
and 100-inch reflectors. Eighteenth series. 
Astrophys. Jour., vol. 94, pp. 396-398 (1941) ; 
Mt. W. Contr., No. 652. 

Investigations on proper motion. XXI. 

Faint members of the Pleiades cluster. As- 
trophys. Jour., vol. 94, pp. 399-406 (1941); 
Mt. W. Contr., No. 653. 

A faint member of the Hyades group. 



Pubs. A. S. P., vol. 54, p. 109 (1942). 



2 4 



CARNEGIE INSTITUTION OF WASHINGTON 



Wilson, O. C. Absolute dimensions of a Wolf- 
Rayet star and the expanding-envelope hy- 
pothesis. Astrophys. Jour., vol. 95, pp. 402- 
420 (1942); Mt. W. Contr., No. 660. 

Three Wolf-Rayet spectroscopic binaries. 

Pubs. A. S. P., vol. 53, p. 295 ( 1 94 1 ) . 

Wilson, Ralph E. The journey of the sun. 
A. S. P. Leaflet, No. 161. 8 pp. (1942). 



— and M. L. Humason. The proper-motion 
star Ross 766. Pubs. A. S. P., vol. 54, p. 156 
(1942). 

— and Paul W. Merrill. Mean absolute 
magnitudes and space motions of the long- 
period variable stars. Astrophys. Jour., vol. 
95, pp. 248-267 (1942); Mt. W. Contr., 
No. 658. 



SPECIAL PROJECTS: ASTRONOMY 



Dirk Brouwer, Yale University Observatory, New Haven, Connecticut. Program 
for the determination of systematic corrections to fundamental catalogues from 
observations of minor planets. (For previous report see Year Book No. 40.) 



The number of plates obtained for this 
program during the year was 569, of which 
181 were secured at the Yale Southern 
Station in Johannesburg, 227 at New 
Haven, and 161 at the Allegheny Observa- 
tory of the University of Pittsburgh. This 
number does not include the observations 
obtained at the Leiden Observatory. The 
work of that observatory was interrupted 
for a few months in the summer of 1940, 
but resumed in August of that year. Re- 
ductions of the Leiden observations for 
the year 1940 were received in manuscript. 
No report for the year 1941 has been 
received beyond word that the work was 
being continued. 

The measurement of plates at Yale Ob- 
servatory has been continued at an in- 
creased rate, the number of plates meas- 
ured during the year being 751. This 
increase was made possible primarily by 
the addition to our staff of Dr. Gustav 
Land. Both Dr. Land and Miss Ruth J. 
Huff devoted full time to this part of the 
work. 

Reductions of the measurements have 
been made under the supervision of Miss 
Louise F. Jenkins, but no attempt has been 
made to keep in step with the measure- 
ments. Greater concentration on the re- 
ductions will soon become desirable. 

The calculation of the perturbations of 
15 asteroids for 24 years, 1924 to 1948, 
was completed, and the numerical integra- 
tion of 5 orbits was extended backward 
to the year 1924. Of the entire first-integra- 
tion program of 15 planets, less than 40 



per cent remains to be done. A large part 
of the uncompleted work concerns the 
planets Ceres, Pallas, Juno, and Vesta. 
For these planets the Astronomisches 
Rechen-Institut in Berlin furnished an- 
nually extensive ephemerides of a quality 
that was more than sufficient for the ob- 
servational requirements. On this account 
work on these 4 orbits could be delayed 
until the orbits of the other planets on the 
program had been fully determined. Dur- 
ing the past year first integrations and 
orbit corrections for Ceres and Pallas were 
made at Yale Observatory by Dr. Hans G. 
Hertz and Dr. Brouwer. Dr. Paul Herget, 
of the Cincinnati Observatory, gave his 
valued cooperation in this part of the pro- 
gram, contributing numerical integrations 
and orbit corrections for the planets Juno 
and Vesta. The orbits of these 4 planets 
are now ready for accurate integrations 
over the 24-year period by the Thomas J. 
Watson Astronomical Computing Bureau. 
Owing to the progress made with the 
numerical integration of the orbits, the 
time has now arrived when useful com- 
parisons of the orbits with observations in 
numerous oppositions can be made, pre- 
liminary to further improvement of the 
orbits. For the planet (7) Iris such work 
was undertaken by Mr. Oscar T. Schultz, 
of the U. S. Naval Observatory. He suc- 
ceeded in representing the observations in 
eight oppositions with a highly satisfac- 
tory degree of accuracy. A similar discus- 
sion of the orbit of (57) Mnemosyne by 
Dr. Land is now in progress. 



25 



26 



CARNEGIE INSTITUTION OF WASHINGTON 



A. Mitchell, University of Virginia, Charlottesville, Virginia. Astronomical 
studies at the Leander McCormic\ Observatory. (For previous reports see Year 
Books Nos. 38 to 40.) 



For a hundred years, astronomers have 
been on a constant search for faint or in- 
visible companions of bright stars. In 
1844, in order to explain the variable 
proper motions of Sirius and Procyon, 
Bessel predicted the presence of a com- 
panion to each of these bright stars. In 
1 861, Alvan G. Clark discovered the com- 
panion of Sirius, in itself one of the most 
interesting stars in the sky, though the 
companion is 10,000 times fainter than 
the primary. In 1896, Schaeberle discov- 
ered the companion of Procyon. In a 
similar manner, through the variable 
proper motion of an nth-magnitude star 
on the McCormick parallax program, Dr. 
D. Reuyl found that the star Ross 614 is a 
double, the first star of the Sirius type 
to be discovered by photographic proc- 
esses. Ross 614 has been followed for 
several years, and the period is about 15 
years. The companion has not been seen 
visually. Dr. Reuyl has found a second 
star with variable proper motion, Cincin- 
nati 1244. The masses of the invisible 
companions must be less than one-tenth 
the mass of the sun. These stars are both 
of dwarf M type with emission lines. It 
appears that stars of this type have a high 
probability of being double. 

Duplicity has been found directly from 
McCormick photographs for the two stars 
Wolf 424 and BD -{-19° 5116. The photo- 
graphs reveal that the former is in fairly 
rapid motion, the distance having de- 
creased from o'.'8 to o"3 in about one year. 
In view of the fact that the scale of the 
McCormick photographs is 1 mm = 20" 
of arc, the centers of the components of 
Wolf 424 are now separated by only 0.015 
millimeter. This is far too small a sepa- 
ration to permit measurement directly, 



but none the less the exquisite definition 
of the McCormick refractor permits the 
detection and measurement of the elliptical 
character of the images of Wolf 424 as 
compared with the circular images of near- 
by stars of the same magnitude. For all 
cases in which duplicity has been estab- 
lished, an attempt is being made to de- 
termine the masses. 

Wolf 630, the visual binary of shortest 
known period, 1.8 years, and of angular 
separation 0V2, is being followed photo- 
graphically by Dr. Reuyl. The feature of 
particular interest in this work is the fact 
that preliminary results of the measures 
seem to indicate inequality of the masses 
in spite of the fact that the photovisual 
magnitudes of the components are equal. 

Another McCormick research on an in- 
teresting double star has been conducted 
by Dr. Reuyl with the collaboration of 
Dr. Erik Holmberg, of the Lund Ob- 
servatory, Sweden. By the use of coarse 
wire grating placed before the object 
glass, Hertzsprung many years ago showed 
that for double stars of unequal but bright 
components of fair angular separation, 
by the use of a grating with appropriate 
widths of wires and interspaces, the first- 
order spectra of the principal star could be 
made equal in magnitude to that of the 
fainter companion. Hertzsprung with 
the Potsdam and Johannesburg refractors, 
and Reuyl with the McCormick refractor 
have obtained photographs extending over 
many years for the double star 70 Ophiuchi. 
The measures of the McCormick grating 
photographs together with those on the 
regular parallax series combined with the 
measures of the Potsdam and Johannes- 
burg photographs were compared with 
Strand's orbit. These comparisons seemed 



SPECIAL PROJECTS: ASTRONOMY 



27 



to give fairly positive information that 70 
Ophiuchi is accompanied by a third in- 
visible star. The assumption of a circular 
orbit about the A or B component of 70 
Ophiuchi, together with the period of 18 
years, seems to indicate the smallest mass 
yet known for any stellar object, namely 
0.01 to 0.02 of the mass of the sun. 

Trigonometric parallaxes continue to be 
the chief research at the McCormick Ob- 
servatory. Through the kindness of Dr. 
Kuiper, of Yerkes and McDonald ob- 
servatories, a number of stars with large 
spectroscopic parallaxes have been put on 
the McCormick program. For many of 
these stars of M type, trigonometric paral- 
laxes have been derived at McCormick. 

The second proper-motion program of 
the McCormick Observatory is nearing 
completion. The measures of both the mo- 
tions and the magnitudes of the 11,300 
stars involved have been finished and the 
spectra for about 7500 of the stars have 
been determined. The proper motions 
in the first publication were reduced to 
the system of the General Catalogue. The 
motions of all stars in both the first and 
second investigations have now been 
reduced to the FK3 system. The motions 
of the more than 29,000 faint stars in the 
two investigations will be discussed inde- 
pendently and in combined solutions. 

The Observatory was represented at the 
Symposium on Galactic Structure held 
May 2-3, 1941, under the auspices of the 
New York Academy of Science by Dr. 
Emma T. R. Williams, who contributed 
a discussion of mean parallaxes derived 
from peculiar motion. 

Dr. A. N. Vyssotsky represented the Ob- 
servatory at the Inter-American Astro- 
physical Conference held February 17-25, 
1942, to celebrate the inauguration of the 
National Astrophysical Observatory at 
Tonanzintla, Mexico. He reported on the 
spectroscopic work in progress with the 



1 o-inch Cooke prismatic camera, and 
pointed out, among other things, the pos- 
sibilities for the discovery of stars with pe- 
culiar spectra. Thus, to date he has picked 
up accidentally 9 new S-type stars and 
4 new planetary nebulae. The total num- 
ber of new dwarf M stars found spectro- 
scopically on McCormick plates has now 
reached more than 50. 

Measurement of proper motions of the 
Cepheids is progressing in satisfactory 
manner. As indicated in earlier Year 
Books, this research is being conducted in 
cooperation with the Mount Wilson Ob- 
servatory. The measures for the 90 regions 
already finished by Dr. Mitchell show an 
average internal probable error of o / . / oo22 
for the proper motion of the Cepheid re- 
ferred to about 16 surrounding stars. 

During the past year astronomers from 
other institutions have been in residence 
at McCormick in order to make use of the 
spectra of faint stars obtained with the 10- 
inch Cooke refractor. Father W. J. Miller, 
a graduate student of Harvard Observa- 
tory, spent six weeks in classifying the 
spectra of more than 2000 stars and in 
comparing his system of classification with 
that of the southern part of the Henry 
Draper Catalogue. Similarly, Dr. A. 
Marguerite Risley, of Randolph-Macon 
Womans College, classified the spectra of 
4000 stars. In each case, the spectra are 
to be used in connection with the sta- 
tistical investigations of the structure of the 
Milky Way in cooperation with Harvard 
College Observatory. 

Another contribution by means of the 
1 o-inch Cooke telescope is the set of 332 
photovisual sequences distributed uni- 
formly over the sky from — 15 ° to +75° 
declination. These were derived from 
equal-altitude polar comparisons by Mr. 
C. A. Wirtanen, and show very satisfactory 
agreement with the I Pv system. 



28 



CARNEGIE INSTITUTION OF WASHINGTON 



In the summer of 1941, while in resi- 
dence at the Mount Wilson Observatory, 
Dr. Mitchell by means of the 60-inch re- 
flector obtained the spectra of about 100 A 
and K stars of the 10th magnitude for the 
determination of their radial velocities. 
The stars for this program were selected 



from the second McCormick proper-mo- 
tion investigation. 

BIBLIOGRAPHY 

Williams, Emma T. R. Mean parallaxes from 
peculiar motions (Symposium on Galactie 
Structure). Ann. New York Acad. Sci., 
vol. 42, pp. 187-199 (1941). 



GEOPHYSICAL LABORATORY 

Washington, District of Columbia 
L. H. ADAMS, Director 



In the summer of 1941 the first step 
was taken toward setting up a compre- 
hensive program of defense research cen- 
tered at the Geophysical Laboratory and 
under the auspices of the National De- 
fense Research Committee of the Office 
of Scientific Research and Development. 
Previously, different members of the sci- 
entific staff had accepted problems pre- 
sented for solution by various govern- 
mental agencies, but the regular scientific 
work was proceeding without major dis- 
turbance. The new undertaking was of a 
magnitude which appeared to require all 
the Laboratory's facilities and personnel. 
At the start some time was required for 
collecting information from military and 
other sources and for delineating the var- 
ious lines of research and development. 
Several of the staff members turned im- 
mediately to the new assignment; others 
proceeded as rapidly as possible to round 
out those parts of the current researches 
that were nearing completion, preparatory 
to laying their customary work aside for 
the duration of the emergency. During 
this transition period there was oppor- 
tunity to put the finishing touches on sev- 
eral investigations and to prepare them for 
publication. It is fortunate that without 
hindering the preparations for our pres- 
ent program of developing new devices 
for offense and defense, the results of a 
number of researches could be collected 
and published, and thus even in a small 
way the continuity of fundamental re- 
search in geophysics could be preserved 
for a while. 

Shortly after the declaration of war, all 
resources of the Laboratory were applied 
toward war work. With few exceptions, 



staff members are now occupied with var- 
ious parts of the war program under- 
taken by the Laboratory. These exceptions 
include one member who is filling an ad- 
ministrative position in a unit of the 
NDRC, one member on leave of absence 
who is a civilian employee of the War De- 
partment, two on leave of absence who are 
civilian employees of the Navy Depart- 
ment, and one on leave of absence who is 
managing a large optical glass plant. De- 
spite the urgent need at the Laboratory for 
experienced investigators, it appeared that 
these persons were rather uniquely quali- 
fied for their respective special tasks, and 
it was judged that in these capacities their 
services would contribute best to the war 
effort. The regular staff has been supple- 
mented by about thirty temporary em- 
ployees, including physicists, mathemati- 
cians, chemists, technicians, and stenog- 
raphers. 

Although almost all the work has been 
on a single unified program in the interest 
of the war effort, two or three smaller as- 
signments have been accepted and carried 
forward under contract. For the main 
undertaking the Geophysical Laboratory 
functions not only in the performance of 
a contract for research and development 
between the Institution and the OSRD, 
according to which the Institution is re- 
imbursed for the cost of new equipment 
and additional personnel; the Laboratory 
is also the focus of a still larger program 
involving a dozen or more contracts with 
universities, institutions, and commercial 
organizations. The Director of the Labora- 
tory is the chairman of a unit in the 
NDRC, and by virtue of this governmental 
appointment is primarily responsible for 



29 



30 



CARNEGIE INSTITUTION OF WASHINGTON 



initiating and carrying forward the pro- 
gram as a whole. An office of this govern- 
mental unit is maintained at the Geo- 
physical Laboratory, and for the handling 
of the official administrative business two 
full-time Civil Service employees are sta- 
tioned there. 



The following is a summary of the regu- 
lar work completed and published during 
the past twelve months. Inasmuch as most 
of the investigations have been referred 
to in previous annual reports, it will per- 
haps suffice merely to present the ab- 
stracts of individual papers. 



SUMMARY OF PUBLISHED WORK 



(1051) Bradleyite, a new mineral, sodium phos- 
phate — magnesium carbonate. Joseph J. 
Fahey. (With X-ray analysis by George 
Tunell.) Amer. Mineralogist, vol. 26, 
pp. 646-650 (1941). 

A new anisotropic fine-grained mineral, 
associated with shortite and carbonaceous 
clay, was found in the drill core of the John 
Hay Jr. Well No. 1 in Sweetwater County, 
Wyoming, at a depth of 1342 feet 10 inches, 
by Mr. Fahey, of the Geological Survey, 
U. S. Department of the Interior, Washing- 
ton, D. C. It has been named bradleyite in 
honor of Dr. W. H. Bradley, of the Geologi- 
cal Survey. Chemical analysis shows that the 
formula is Na 3 P0 4 ■ MgCO. ; . X-ray powder 
diffraction photographs of bradleyite were 
made by Dr. Tunell, of the Geophysical 
Laboratory, with filtered copper K radiation 
and show that it does not contain MgC0 3 
in the form of magnesite. The spacings and 
intensities of the X-ray powder photograph 
of bradleyite are tabulated to aid in its future 
identification. 

(1052) Introduction to symposium on "Reactions 
and equilibria in chemical systems under 
high pressure" (Amer. Chem. Soc). 
R. E. Gibson. Chem. Revs., vol. 29, pp. 
439-445 (i94i)- 

From a detached thermodynamic point of 
view it may seem surprising that studies of 
the effects of temperature and of composition 
variations should so far have outrun studies 
of the effects of pressure, because the three 
variables — pressure, temperature, and com- 
position — are of coordinate thermodynamic 
importance in determining the state of a 
chemical system. The purpose of this sym- 



posium is to take cognizance of the fact that 
interest in the behavior of chemical systems 
under pressure changes has increased in the 
past decade, and to consider some recent ad- 
vances that have been made. By way of intro- 
duction to the papers given in the symposium, 
attention is called to six general fields in the 
study of material systems under high pressure 
that are of interest to chemists, as follows: 
(1) the displacement of equilibria in homo- 
geneous systems under high pressure; (2) the 
displacement of equilibria in heterogeneous 
systems; (3) acceleration or retardation of 
chemical reactions by pressure; (4) new 
phenomena; (5) knowledge of the behavior 
of naturally occurring substances under ex- 
treme conditions; (6) new methods of at- 
tacking old problems. 

In order to illustrate the place of the vari- 
ous types of high-pressure investigation in 
the general scheme of physical chemistry and 
to answer the still frequent question 'What 
do P — V — T measurements have to do with 
chemistry?" a chart showing the interrela- 
tions among the various activities is given. 

(1053) Equilibrium in heterogeneous systems at 
high temperatures and pressures. L. H. 
Adams. Symposium on "Reactions and 
equilibria in chemical systems under high 
pressure" (Amer. Chem. Soc). Chem. 
Revs., vol. 29, pp. 447-459 (1941). 

Following a summary of the principles in- 
volved in chemical equilibria, there is given 
a brief discussion of apparatus and experi- 
mental procedure for investigations in this 
field. Special attention is paid to systems that 
include a solid phase. The effects of pressure 
and of temperature are considered separately 



GEOPHYSICAL LABORATORY 



31 



and in combination. A resume is presented 
of certain experimental results obtained at 
pressures extending to several thousand at- 
mospheres and at temperatures exceeding 
iooo C. Reference is made to the applica- 
tion of these results to manufacturing proc- 
esses and also to volcanology and other 
branches of geophysics. 

(1054) Radioactivity of ocean sediments. IV: 
The radium content of sediments of the 
Cayman Trough. C. S. Piggot and 
Wm. D. Urry. Amer. Jour. Sci., vol. 240, 
pp. 1-12 (1942). 

The radioelements in the uppermost layers 
of the sediments at the bottom of the ocean 
are not in equilibrium, and a study of the 
relations that exist in material of uniform 
character, lying under very deep water, is 
of fundamental importance in any interpre- 
tation of more complex sediments, such as 
are produced under areas of intermittent 
glaciation or other disturbing influences. 
Therefore material from a great ocean deep 
situated in middle latitudes is of special 
value. The Cayman Trough, lying south of 
Cuba, and including the Bartlett Deep, is a 
peculiarly satisfactory location for such 
studies. Here the water is almost stationary 
and the biologic environment has remained 
quite uniform for a long time. Among the 
many radioactive elements, uranium, ionium, 
and radium have sufficiently long lives to 
be of special importance in such studies. A 
history of these three elements is reflected in 
the variation of the radium content of ocean 
sediments with depth below the ocean floor. 
Measurements of this variation demonstrate 
that the concentrations of uranium, ionium, 
and radium at any given time are established 
by the usual laws of radioactivity governing 
the growth and decay of radioelements in 
a system that is not in radioactive equilibrium. 
The experimental results must be adjusted 
to the condition of the sample in the undis- 
turbed sediment. This requires a knowledge 
of the history of the specimens, from the time 
when the sediment was taken by the core 
sampler to the time at which the specimens 
were analyzed. The relation between radium 



content and depth in a given ocean sediment 
promises a method of determining the rate 
of accumulation of the deposit at that place. 

(1055) Melting and transformation temperatures 
of mineral and allied substances. F. C. 
Kracek. Section n of Special Papers 
No. 36, Geol. Soc. Amer., "Handbook of 
physical constants," ed. Francis Birch, 
pp. 139-174 (1942). 

This is a critical compilation of melting 
points and other characteristic temperatures 
for minerals and mineral-like artificial com- 
pounds and other substances which may be 
of interest to the worker in geological sciences. 
Data are given for the individual compounds, 
and for binary and higher mixtures of such 
compounds, so far as they are known. The 
material is arranged under the following 
headings: elements; oxides; hydrous and hy- 
drated oxides; binary aluminates; binary 
borates; binary oxide systems; three or more 
oxides (except Si0 2 ); binary silicates; ternary 
and higher silicate systems (except systems 
with AI0O3 and B 2 3 ); aluminosilicates; 
borosilicates; miscellaneous systems contain- 
ing silicates; hydrothermal alteration of sili- 
cates and other minerals; carbonates; sulfates; 
oxygen salts; haloids; sulfide-type minerals; 
ternary sulfides. The aim in compiling the 
tables has been to describe the known thermal 
reactions of the compounds and the systems 
briefly, but in enough detail to be of use to 
an investigator not only in the laboratory but 
also in the field, where extensive reference 
books are usually not available. 

(1056) Effect of pressure on phase equilibria in 
binary condensed systems. R. E. Gibson. 
Section 13 of Special Papers No. 36, Geol. 
Soc. Amer., "Handbook of physical con- 
stants," ed. Francis Birch, pp. 187-202 
(1942). 

Although very few data on the effect of 
pressure on binary systems of direct geologi- 
cal interest are available, a variety of chemical 
systems have been studied experimentally over 
ranges of pressure and temperature, and these 
systems are sufficiently varied to give a gen- 
eral picture of the types of effect that may 



32 



CARNEGIE INSTITUTION OF WASHINGTON 



be expected. The compilation is not exhaus- 
tive, but an attempt has been made to in- 
clude all the different types of behavior that 
have been observed, and a list of references 
is appended with a notation of the contents 
of the papers cited. The following headings 
show the scope of the compilation: I. Binary 
condensed systems containing water: (a) ef- 
fects of relatively low pressures on the solu- 
bility of salts in water at constant tempera- 
ture; {b) effects of high pressures on the 
solubility of solids in water; (c) effect of 
pressure on the temperature of the incongru- 
ent melting of hydrates. II. Binary condensed 
systems composed of organic compounds: 
(a) pressure — solubility relations at con- 
stant temperature; (b) effect of pressure on 
the eutectic temperature and composition; 
(c) miscellaneous examples. 

(1057) Temperature — pressure — volume and 
phase relations of water. Roy W. Goran- 
son. Section 14 of Special Papers No. 36, 
Geol. Soc. Amer., "Handbook of phys- 
ical constants," ed. Francis Birch, pp. 
203-212 (1942). 

In this compilation are presented tables of 
the most probable values for the specific 
volume of water in various forms over a 
considerable range of temperature and at 
pressures up to 1200 bars. Included also is 
information on: the volume change associ- 
ated with various transformation points; the 
heats of vaporization and heat capacity of 
water; the equilibrium pressures and tem- 
peratures at the several triple points; and 
data for the various equilibrium curves 
including melting curves. 

(1058) Heat capacity; heat of fusion. Roy W. 
Goranson. Section 16 of Special Papers 
No. 36, Geol. Soc. Amer., "Handbook 
of physical constants," ed. Francis Birch, 
pp. 223-242 (1942). 

The existing information on the heat ca- 
pacity of minerals and rocks and the heats 
of fusion and transformation is tabulated in 
convenient form. The heat capacities are 
calculated in terms of the true or instantane- 
ous values over a range of temperatures ex- 



tending in many instances from —200 to 
1200 C. Full literature references are given. 

(1059) Radioactivity of ocean sediments. V: 
Concentrations of the radio-elements and 
their significance in Red clay. Wm. D. 
Urry and C. S. Piggot. Amer. Jour. Sci., 
vol. 240, pp. 93-103 (1942). 

The relationship between the radioele- 
ments uranium, ionium, and radium in those 
deep-sea deposits known as "Red clay" is 
similar to that previously described for the 
calcareous sediments of the ocean. The Red 
clay, represented by a core 246 cm long, is 
distinguished from the calcareous sediments 
by a very rapid decrease in the radium con- 
tent just below the surface of the ocean bot- 
tom, and by the attainment of the final equi- 
librium between the above three radioele- 
ments in the bottom quarter of the core, 
which signifies a very slow deposition as 
compared with that of the calcareous deposits. 
The radium content at equilibrium with the 
uranium is only 7 per cent of that near the 
surface of this Red clay deposit. The high 
surface concentrations of radium and ionium, 
particularly in Red clay, are therefore only 
transient phenomena, produced by some un- 
known mechanism which concentrates these 
elements, relative to the uranium content, 
during the deposition of the sediment. 

(1060) Methods and instruments used in min- 
eralogy. F. E. Wright. Amer. Min- 
eralogist, vol. 27, pp. 145-154 (1942). 

This paper was delivered before a joint 
session of the Mineralogical and Geological 
Societies of America as the address of the 
retiring president of the Mineralogical So- 
ciety. It considers briefly a few of the methods 
and instruments now in use by mineralogists 
in determining the physical, crystallographi- 
cal, and chemical properties of minerals. Ex- 
perience has shown that in experimental work 
the introduction of a new method or a new 
instrument may enable the observer to explore 
fields heretofore inaccessible for lack of the 
proper weapons of attack. In present war- 
time surroundings this condition is especially 
evident, as is also the importance of adequate 



GEOPHYSICAL LABORATORY 



33 



supplies of the instruments of warfare and 
of new methods and weapons of defense and 
of offense. 

In particular, the paper discusses three tools 
useful to mineralogy — the reflecting goni- 
ometer, the petrographic microscope, and 
X-ray apparatus — for the purpose of illustrat- 
ing how progress in mineralogy has been de- 
pendent on the availability of suitable methods 
and instruments of attack; and how an in- 
strument useful in one branch of science may 
prove to be equally serviceable in another 
field, if properly adapted to meet the condi- 
tions imposed in the new field. 

(1061) The radio-elements in non-equilibrium 
systems. Wm. D. Urry. Amer. Jour. Sci., 
vol. 240, pp. 426-436 (1942). 

In an isolated system in which the radio- 
elements are not in equilibrium, the relative 
amounts of the members of a radioactive 
series are established by time only. Such a 
system exists in the uppermost sediments of 
the ocean bottom, and the relative amounts 
of uranium, ionium, and radium have been 
determined in a number of core samples of 
such ocean-bottom deposits. In order to as- 
sign time intervals to these sediments, an 
equation was needed, but the general equa- 
tion could not be found in the literature, 
although special cases for simple initial con- 
ditions have been treated. The general equa- 
tion has now been developed. Its derivation 
assumes no particular initial amounts of the 
various members of a radioactive series. 

(1062) The system CaO— FeO— A1 2 3 — Si0 2 . I: 
Results of quenching experiments on five 
joins. J. F. Schairer. Jour. Amer. Ceram. 
Soc, vol. 25, pp. 241-274 (1942). 

A study of the quaternary system CaO — 
FeO — Al 2 3 — Si0 2 was undertaken in order 
to obtain information about the mutual melt- 
ing relations of pyroxenes, pyroxenoids, 
olivines, and melilites — four important groups 
of rock-forming minerals — and to acquire 
specific knowledge of their chemical composi- 
tions. Each of these mineral groups involves 
extensive solid solutions. 

6 



In this preliminary paper, liquidus data 
are presented for five planes within a regular 
tetrahedron used to represent the phase rela- 
tions in the quaternary system. These five 
planes were chosen to explore that portion 
of the tetrahedron containing compositions 
of interest to igneous petrology. 

The results of quenching experiments 
on 216 separate compositions are given. 
Liquidus data are complete for five joins 
through the tetrahedron: Si0 2 — anorthite — 
FeO, anorthite— A1 2 3 — FeO, CaSi0 3 — anor- 
thite — FeO, gehlenite — anorthite — FeO, and 
CaSi0 3 — gehlenite — FeO. 

Although data are given for only five joins, 
it has been shown how these data indicate 
within approximate limits the temperatures 
and compositions of eleven quaternary invari- 
ant points and show the direction of change 
of composition of the liquid phase during 
crystallization in a large portion of the 
tetrahedron. 

An equilibrium diagram for the ternary 
system FeO — A1 2 3 — Si0 2 is given, but the 
data on which it is based will be published 
in a separate paper. 

Much information on the coexistence of 
solid phases is presented, and the approxi- 
mate composition of the liquid phase through- 
out the crystallization process may be 
followed. 

The application of these results to refrac- 
tories and slags of interest in ceramics and 
metallurgy is briefly discussed. 

(1063) Time relations in ocean sediments. C. S. 
Piggot and Wm. D. Urry. Bull. Geol. 
Soc. Amer., vol. 53, pp. 1187-1210 (1942). 

Nonequilibrium between the radioactive 
elements in the surface of the ocean bottom 
provides a method of measuring intervals 
of time in the past 300,000 years. The well 
preserved geological and biological history of 
the ocean basins has been worked out by 
others for many of the cores of ocean sedi- 
ments obtained by Piggot, and the above 
method of measuring time intervals in years 
has been applied to these cores. The results 
indicate that the effects of glaciation on the 



34 



CARNEGIE INSTITUTION OF WASHINGTON 



continents are contemporaneous with equiva- 
lent effects on the type of deposit in the 
ocean bottom; that the effects of glaciation 
on the type of ocean sediment are widespread, 
extending in the northern hemisphere at least 
to the Caribbean Sea; and that within short 
intervals of time there is in the ocean bottom 
a considerable variation, attributable directly 
or indirectly to climatic changes, which, prob- 
ably because of the continuous effacement of 
the evidence on land, has not been reported 
in studies of continental glaciation. 

This method cannot compete in accuracy 
with the use of the annual varved clays for 
measuring very recent intervals of time, but 
it has the advantages of (i) application to a 
considerable area of the earth's surface; 
(2) reference to the present time; and (3) ap- 
plicability to at least half of the Pleistocene 
epoch. 

The rate of deposition of ocean sediments 
is treated as a subsidiary problem. The ob- 
vious step from the determination of time 
intervals in a core to the rate of deposition 
of the sediment represented by the core is 
complicated by the present incomplete knowl- 
edge of the distortion of the sediment in the 
process of obtaining the sample. The aver- 
age rates of deposition agree with estimates 
by other methods, some of which, however, 
are open to the same criticism. There is 
apparently considerable variation in the rate 
of deposition of ocean sediments in the past, 
but the data can be only qualitative at present 
because of the above complication. 

(1064) Pyrrhotite; melting relations and com- 
position. Einar Jensen. Amer. Jour. Sci., 
vol. 240, pp. 695-709 (1942). 

The melting relations of pyrrhotite and 
adjoining portions of the system FeS — Fe 
were studied by means of the differential 
heating-cooling-curve method. The mixtures 
were sealed in specially designed silica glass 
containers to prevent oxidation and loss of 
sulfur at high temperatures. A preparation 
corresponding to the formula FeS melts over 
a large temperature interval with dissocia- 
tion into a solid richer in sulfur and 
a liquid richer in iron. Increasing sulfur 



raises the melting temperatures to a maxi- 
mum where the composition Fei 2 Si 3 melts 
sharply like a simple compound. Mix- 
tures with more iron than FeS show eutectic 
melting. A diagram has been made show- 
ing these melting relations, and other rela- 
tions at lower temperatures taken from the 
literature. 

(1065) Origin of shapes of quartz sand grains. 
Earl Ingerson and Joseph L. Ramisch. 
Amer. Mineralogist, vol. 27, pp. 595-606 
(1942). 

The quartz grains in many metamorphic 
rocks tend to be elongate parallel to the c-axis. 
Recently a similar elongation has been ob- 
served in the quartz grains of unmetamor- 
phosed sandstones; also another elongation 
parallel to the unit rhombohedron. Current 
explanations ascribe these elongations to frac- 
tures parallel to these directions and differ- 
ential abrasion during transport. To check 
these explanations, three sets of experiments 
were carried out, with the following results: 

(1) There was a decided tendency for some 
samples of quartz to fracture parallel to the 
unit rhombohedron, but no sample showed 
a pronounced fracture parallel to the c-axis. 

(2) Quartz grains from weathered (but un- 
disturbed) quartzose igneous and metamor- 
phic rocks show a tendency to be elongate 
parallel to prism and unit rhombohedral 
faces. (3) Abrasion tests on oriented prisms 
show that quartz is harder on prism faces 
than normal thereto. It is concluded that 
the elongation of quartz sand grains is due 
to original shape rather than to fracture and 
differential abrasion during transport. 

(1066) A method for the summation of the 
Fourier series used in the X-ray analysis 
of crystal structure. A. L. Patterson and 
George Tunell. Amer. Mineralogist, vol. 
27, pp. 655-678 (1942). 

In recent years there has been a very wide- 
spread use of the Fourier series in the analysis 
of the data obtained by the diffraction of 
X-rays in crystals. The electron density in a 
crystal can be represented by a three-dimen- 
sional Fourier series in which the coefficients 



GEOPHYSICAL LABORATORY 



35 



are the structure factors F(h\l), the intensi- 
ties of the diffraction lines, corrected for 
certain known trigonometric factors, being 
proportional to \F(h\l)\' 2 . The projection 
of the electron density on a plane perpendicu- 
lar to a zone axis can be represented by a 
two-dimensional series using only the F's of 
the diffractions in that zone. Various methods 
leading to the successful analysis of X-ray 
data have been devised which depend on 
the summation of Fourier series. Routine 
methods for carrying out the summation of 
such series have become part of the neces- 
sary equipment of any laboratory specializ- 
ing in X-ray analysis. 

This paper describes in detail a method 
that has proved useful in the summation of 
one-dimensional Fourier series, and a proce- 
dure that enables this method to be applied 
to the summation of two-dimensional series 
such as those by which the electron density of 
a crystal is represented as a function of the 
coordinates in the projection of the unit cell 
on a particular plane. The method, like those 
of Robertson and of Lipson and Beevers, 
utilizes cardboard strips, each carrying a series 
of values of a certain trigonometric function, 
but differs from the other two in that the 
selection of numbers to be added from a 
series of strips for a given point of the unit 
cell is accomplished by one of a set of stencils, 
the strips being laid on a rack in the order 
of the Miller indices of the corresponding 
crystal planes, and the stencil being laid over 
the assembly of strips. The stencils are placed 
over the assembly of strips one at a time in 
serial order, and the calculated results, in the 
summation of the two-dimensional series, 
then give the electron densities along one 
line of points in the projection. Repetition 
of this process with the next assembly of 
strips yields the electron densities along the 
next line of points. Experience has shown 
that this method is well adapted to the range 
of F-values (or of |F| 2 -values) from o to iooo. 

(1067) Apparatus for direct measurement of 
linear structures. Earl Ingerson. Amer. 
Mineralogist, vol. 27, pp. 721-725 (1942). 

Modern methods of metamorphic and igne- 
ous geology frequently require that large 



numbers of linear elements be measured in 
the field. Under many circumstances this is 
a difficult and time-consuming operation with 
the ordinary compasses in use for geologic 
surveying. 

A piece of apparatus has been devised that 
can save much time in taking a series of 
lineation measurements, since only a single 
placing is required for each measurement. 
It consists of a compass mounted with a 
graduated semicircle weighted so that it re- 
mains vertical; the compass is provided with 
a weighted pointer which keeps it horizontal. 
This arrangement is swung on pivots in a 
frame having a straight edge that can be 
placed on, or parallel to, a linear structure in 
the field. Direction of pitch is read on the 
compass and angle of pitch is read on the 
vertical circle. 

The apparatus can be used on overhanging 
surfaces and on outcrops where no planar 
structure is apparent just as well as on the 
more commonly encountered type of outcrop. 
Also, dip and strike can be determined by 
measuring the dip just as a lineation is meas- 
ured, and taking the direction normal to 
the pitch as the strike of the planar structure. 

(1068) The binary system CaSi0 3 — diopside and 
the relations between CaSiO s and aker- 
manite. J. F. Schairer and N. L. Bowen. 
Amer. Jour. Sci., vol. 240, pp. 725-742 
(1942). 

The system CaSi0 3 — diopside is the type 
of binary system involving both solid solu- 
tion and enantiotropism. The temperature 
of the inversion of wollastonite (/?CaSi0 3 ) 
to pseudowollastonite (aCaSi0 3 ) is raised by 
solid solution of diopside in wollastonite, and 
in compositions between o and 21 per cent 
diopside there is an inversion interval. In 
fact, the inversion temperature is raised so 
much (from 1125 to 1368 C) that wollas- 
tonite solid solutions actually appear on the 
liquidus. There is little or no solid solution 
of diopside in pseudowollastonite. There is 
a eutectic at 1358 ±2° C and at 62 weight 
per cent diopside. At the eutectic, crystals 
of pure diopside and of wollastonite solid 
solution with the maximum amount of diop- 
side (22 per cent) are in equilibrium with 



36 



CARNEGIE INSTITUTION OF WASHINGTON 



liquid. No CaSiO s enters into solid solution 
in diopside crystals. At temperatures below 
the eutectic, wollastonite solid solution crys- 
tals contain less diopside than at the eutectic, 
and crystals formed at higher temperatures 
therefore show the phenomenon of unmixing 
at lower temperatures. 

The system CaSiO- — akermanite shows the 
simple eutectic type of melting diagram with 
the eutectic between pseudowollastonite and 
akermanite at 1400 ±2° C and at 57 weight 
per cent akermanite. There is no solid solu- 
tion of akermanite in either wollastonite or 
pseudowollastonite. The system is binary at 
all temperatures at which liquid is present, 
but because of the instability of akermanite 
at temperatures below about 1325 ° C, the 
system ceases to be binary in certain composi- 
tions and at certain temperatures. 

The relations between the metasilicate 
molecules present in pyroxenes and the related 
pyroxenoids are briefly discussed, and the 
lack of mutual solid solubility between py- 
roxenoids and melilites is pointed out. 

(1069) The system CaSi0 3 — diopside — anorthite. 
E. F. Osborn. Amer. Jour. Sci., vol. 240, 
pp. 751-788 (1942). 

The plane CaSi0 3 — diopside — anorthite oc- 
cupies an important position within that part 
of the quaternary system CaO — MgO — 



Al 2 O a — Si0 2 of interest to the geologist. New 
data are presented for compositions lying in 
this plane, and the phase relations are dis- 
cussed with the aid of a series of diagrams. 
A ternary reaction point is present at 1245 C, 
and the lowest temperature at which liquid 
exists in the system under equilibrium condi- 
tions is 1236 . The alleged compound 
5CaO • 2MgO • 6Si0 2 does not appear in the 
system, as formerly believed. Data are pre- 
sented supporting the evidence of Schairer 
and Bowen that this compound does not exist. 
The crystals of diopside appearing in the 
system are slightly aluminous. Consequently, 
the system is not completely ternary. Some 
additional data are presented for the limiting 
systems CaSi0 3 — anorthite and diopside — 
anorthite. 

(1070) Glass. George W. Morey. In Rogers' 
Manual of industrial chemistry, 6th ed., 
chap. 20, pp. 775-813. New York, D. Van 
Nostrand Co. (1942). (No separates 
available for distribution.) 

The subjects of this section of the revised 
edition of the book are treated under the 
following subheads: historical, definition and 
structure, composition, properties, manufac- 
ture, products, and economics of glasses. 

(1071) Annual Report for 1941-1942. 



BIBLIOGRAPHY 



Adams, L. H. Equilibrium in heterogeneous 
systems at high temperatures and pressures. 
Symposium on "Reactions and equilibria in 
chemical systems under high pressure" 
(Amer. Chem. Soc). Chem. Revs., vol. 29, 
pp. 447-459 (1941)- 

Bowen, N. L. See Schairer, J. F. 

Fahey, J. J., and G. Tunell. Bradleyite, a new 
mineral, sodium phosphate — magnesium car- 
bonate. Amer. Mineralogist, vol. 26, pp. 646- 
650 (1941)- 

Gibson, R. E. Introduction to symposium on 
"Reactions and equilibria in chemical sys- 
tems under high pressure" (Amer. Chem. 
Soc). Chem. Revs., vol. 29, pp. 439-445 
(1941). 

Effect of pressure on phase equilibria in 

binary condensed systems. Section 13 of 



Special Papers No. 36, Geol. Soc. Amer., 
"Handbook of physical constants," ed. Fran- 
cis Birch, pp. 187-202 (1942). 
Goranson, R. W. Temperature — pressure — vol- 
ume and phase relations of water. Section 14 
of Special Papers No. 36, Geol. Soc. Amer., 
"Handbook of physical constants," ed. 
Francis Birch, pp. 203-212 (1942). 

Heat capacity; heat of fusion. Section 16 

of Special Papers No. 36, Geol. Soc. Amer., 
"Handbook of physical constants," ed. Fran- 
cis Birch, pp. 223-242 (1942). 

Ingerson, E. Apparatus for direct measurement 
of linear structures. Amer. Mineralogist, 
vol. 27, pp. 721-725 (1942). 

and J. L. Ramisch. Origin of shapes of 

quartz sand grains. Amer. Mineralogist, 
vol. 27, pp. 595-606 (1942). 



GEOPHYSICAL LABORATORY 



37 



Jensen, E. Pyrrhotite; melting relations and 
composition. Amer. Jour. Sci., vol. 240, pp. 
695-709 (1942). 

Kracek, F. C. Melting and transformation tem- 
peratures of mineral and allied substances. 
Section 11 of Special Papers No. 36, Geol. 
Soc. Amer., "Handbook of physical con- 
stants," ed. Francis Birch, pp. 139-174 (1942). 

Morey, G. W. Glass. In Rogers' Manual of 
industrial chemistry, 6th ed., chap. 20, pp. 
775-813. New York, D. Van Nostrand Co. 
(1942). (No separates available for dis- 
tribution.) 

Osborn, E. F. The system CaSi0 3 — diopside — 
anorthite. Amer. Jour. Sci., vol. 240, pp. 
751-788 (1942). 

Patterson, A. L., and G. Tunell. A method 
for the summation of the Fourier series used 
in the X-ray analysis of crystal structure. 
Amer. Mineralogist, vol. 27, pp. 655-678 
(1942). 

Piggot, C. S., and Wm. D. Urry. Radioactivity 
of ocean sediments. IV: The radium con- 
tent of sediments of the Cayman Trough. 
Amer. Jour. Sci., vol. 240, pp. 1-12 (1942). 



Time relations in ocean sediments. 

Bull. Geol. Soc. Amer., vol. 53, pp. 1187- 
1210 (1942). 

See Urry, Wm. D. 



Ramisch, J. L. See Ingerson, E. 

Schairer, J. F. The system CaO — FeO — A1 2 3 — 
Si0 2 . I: Results of quenching experiments 
on five joins. Jour. Amer. Ceram. Soc, 
vol. 25, pp. 241-274 (1942). 

and N. L. Bowen. The binary system 

CaSi0 3 — diopside and the relations between 
CaSi0 3 and akermanite. Amer. Jour. Sci., 
vol. 240, pp. 725-742 (1942). 

Tunell, G. See Fahey, J. J.; Patterson, A. L. 

Urry, Wm. D. The radio-elements in non-equi- 
librium systems. Amer. Jour. Sci., vol. 240, 
pp. 426-436 (1942). 

and C. S. Piggot. Radioactivity of ocean 

sediments. V: Concentrations of the radio- 
elements and their significance in Red clay. 
Amer. Jour. Sci., vol. 240, pp. 93-103 (1942). 
See Piggot, C. S. 



Wright, F. E. Methods and instruments used 
in mineralogy. Amer. Mineralogist, vol. 27, 
pp. 145-154 (1942). 



DEPARTMENT OF TERRESTRIAL MAGNETISM 

Washington, District of Columbia 
JOHN A. FLEMING, Director 

SUMMARY 



The progress of geophysical research in 
which international collaboration plays an 
important part has been further retarded 
during the report-year, July i, 1941 to 
June 30, 1942, by the extension of the war 
in which all the great powers of the Earth 
have become involved. Studies of terres- 
trial magnetism and electricity have not 
escaped the disastrous effects of this crisis. 
Field-operations of the Department, which 
have been one of the international aspects 
of the regular program, have had to be 
abandoned until the return of normal in- 
tercourse among nations. Fortunately, 
magnetic surveys by organizations and 
individuals in many countries have offset 
in some degree the inadequacy of data 
caused by this curtailment. Fortunately, 
also, there are many observatories situated 
in regions not affected as yet by military 
operations which are able to continue their 
recordings and compilations of data on the 
progress of secular changes, so necessary 
in keeping isomagnetic charts current for 
purposes of navigation and surveys in the 
air and on land and sea. 

The widespread demands for application 
to the war effort of the results of past 
and present investigations have again em- 
phasized the practical value of the many 
aspects of the Department's researches in 
Earth physics. Many of the facilities of per- 
sonnel, laboratory, shop, and buildings, at 
Washington and at the observatories, were 
deflected to investigations and solutions of 
war problems. A number of the staff were 
assigned upon request to special duties else- 
where. Thus there has been possible only 



a somewhat limited continuation of the 
regular program; nevertheless, it is pos- 
sible to include in this report a considera- 
ble amount of worth-while development. 
Many items of scientific value were de- 
veloped in the investigation of special war 
problems. 

In conformity with the action of the 
Trustees, the services of the regular scien- 
tific and administrative personnel and the 
use of facilities have been contributed with- 
out charge to the government. These serv- 
ices by the 89 budgeted scientific and ad- 
ministrative staff members during the re- 
port-year included nearly 36,400 hours and 
over 6200 hours, respectively, for the two 
groups; the corresponding totals for the 
whole period of the emergency since 1940 
were 56,400 and 11,200 hours. On June 30, 
1942, ten of the regular and temporary 
personnel were on leave of absence. To 
assist in the development of urgent projects 
for the Army and Navy and other govern- 
mental agencies, a number of contracts at 
cost without overhead were undertaken. 
The peak number of additional investiga- 
tors engaged on account of these contracts 
during the year, including physicists, en- 
gineers, technicians, and administrative as- 
sistants — many through the generous ac- 
tion of universities and industrial organi- 
zations in granting leaves of absence for 
the emergency — was 211. 

Review of Year's Progress 

Measures of geomagnetic activity. Re- 
ports on the three-hour-range indices of 
geomagnetic activity were received for the 



39 



40 



CARNEGIE INSTITUTION OF WASHINGTON 



calendar year 1940 from 25 observatories, 
that is, 18 in addition to the 5 in the 
United States of the Coast and Geodetic 
Survey, and 2 of the Institution in Peru 
and Western Australia. The disruptions 
caused by the war have reduced the total 
number of observatories reporting these 
indices during 1941 to 19. It is possible, 
however, to give partial effect to the reso- 
lution adopted in 1939 by the International 
Association of Terrestrial Magnetism and 
Electricity, according to which the three- 
hour-range indices were to replace from 
1940 the numerical characterization of days 
previously used. The Department has tab- 
ulated, summarized, and published the 
values supplied. 

Geomagnetic investigations. Average 
values of the disturbance of daily varia- 
tion, storm-time variation, solar daily vari- 
ation, daily means of disturbance, and non- 
cyclic change for international disturbed 
and quiet days were derived. Tables of 
post-perturbation and annual variation for 
the period 1905-1937 were completed. Der- 
ivations for the equator were made of the 
storm-time and disturbance daily variations 
day by day for the same period. These new 
data are at present being used in the re- 
duction to epoch of the extensive magnetic 
measurements by the Department on land 
and sea. The Department's isoporic charts 
for the epoch 1 920-1 925 were redrawn, 
and results for the region of the Pacific 
Ocean incorporated therein; use was made 
of consistency-tests suggested by Chapman 
in obtaining improved estimates of secular 
change. An attempt is also being made to 
obtain, by analytic continuation, improved 
estimates of measures of the Earth's mag- 
netism in high latitudes from the better- 
determined values in low and middle lati- 
tudes. 

The probability of ranges in the mag- 
netic elements greater than various as- 
signed magnitudes was estimated for any 



latitude, and the probabilities per day of 
magnetic storms of various intensities were 
deduced. A study of methods of predic- 
tion of fluctuations in geophysical phe- 
nomena from observed changes in the past 
was continued. 

Electric current-systems of bays and the 
annual variation were deduced. The in- 
vestigation of the relations of geomagnetic 
with solar and other cosmic data was con- 
tinued. Attempts to forecast geomagnetic 
and ionospheric conditions several days in 
advance were inaugurated and fair success 
was attained. 

Terrestrial electricity. Ionization-meters 
were designed, constructed, and tested for 
use in a more precise investigation of the 
question whether the amount of radio- 
active matter in the Earth, measured in 
recent years by other methods, is adequate 
to account for the rate at which ions are 
formed in the air over land by agencies 
other than cosmic radiation. 

Nuclei of condensation, entities which 
serve as starters in the formation of water- 
drops and also affect the electrical state of 
the atmosphere, were further investigated, 
with special regard to their nature, the 
sources of supply, the manner of dissemi- 
nation, and the rate of loss from the at- 
mosphere. The technique of counting 
these nuclei was also critically studied and 
decisions were reached on some disputed 
points. 

Investigations of atmospheric-electric 
phenomena registered at the Institution's 
observatories (Watheroo in Western Aus- 
tralia and Huancayo in Peru) indicate 
rather clearly that at Watheroo, during 
both day and night, nuclei introduced into 
the atmosphere from sources on the Earth 
are disseminated throughout a stratum ex- 
tending from the Earth to a height of at 
least 1 km; at Huancayo, where nuclei 
are in much greater concentration than at 
Watheroo, they are also distributed in a 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



41 



stratum to a height of about 1.5 km dur- 
ing daytime, but at night in the dry season 
a shallow stratum of stable air often 
forms and in this the concentration of 
nuclei diminishes during the night to less 
than one-tenth the concentration in day- 
time. There are corresponding large 
changes in the atmospheric-electric ele- 
ments. 

Attention was given to a number of 
practical problems, chiefly in aeronautics, 
which touch some branch of atmospheric 
electricity or associated subjects. 

Ionosphere. Three complete automatic 
ionospheric recorders were in continuous 
operation in the field at the Watheroo, 
Huancayo, and College observatories. All 
reductions and tabulations were kept cur- 
rent and promptly forwarded. Extended 
analyses of the ionospheric data were con- 
fined to practical applications of value to 
the war effort. 

Interpretations of ionospheric reactions 
during magnetic storms were continued. 
Accumulating evidence indicates a post- 
perturbation effect which may be world- 
wide in nature. Following several of the 
magnetic disturbances, simultaneous rapid 
decreases of electron-density in the F2- 
region were recorded both at Huancayo 
and at Watheroo. The trend of recovery 
and the time of reaching normal conditions 
at both stations appear to be closely related. 

Developmental and experimental work 
was likewise confined largely to wartime 
applications. Tests of the automatic cam- 
era for the recording of aurora were com- 
pleted under actual operating conditions 
at temperatures down to —20° F. The 
constant-voltage controllers were for- 
warded to Huancayo and Watheroo fol- 
lowing testing and adjustment at the 
Washington office. 

The Department's policy of full coopera- 
tion with government agencies and with 
qualified representatives of allied govern- 



ments was continued and expanded. Sev- 
eral papers dealing with ionospheric char- 
acteristics and related phenomena includ- 
ing radio wave-propagation were prepared. 
The technique of measurement of inten- 
sity of the Earth's magnetic field in the 
ionosphere which was applied to obser- 
vations at Huancayo may introduce an 
important new field of research linking 
ionospheric and geomagnetic analyses even 
more closely than at present. 

Nuclear physics. Some progress was 
made in improved functioning of the pres- 
sure electrostatic generator in the Atomic- 
Physics Observatory, but reasonable expec- 
tations of 4 to 5 million electron-volts on 
the tube for this generator are not yet at- 
tained. 

Although slowed down by lack of per- 
sonnel and difficulties in obtaining ma- 
terials and appurtenances, the 60-inch cy- 
clotron installation was so well advanced 
that satisfactory tests of magnet and vac- 
uum-system (including pumps, valves, 
vacuum-chamber, and radio-frequency 
electrode housing) could be made. The 
vacuum-pressure was lower than 5 X io" G 
mm of mercury. The magnet was found to 
produce a field greater than 17,000 gauss. 
In terms of probable deuteron-beam en- 
ergy, this field promises an upper limit of 
about 27 million electron-volts — consider- 
ably more than there was reason to expect 
from experience elsewhere. 

The advantages of the use of this equip- 
ment for producing artificially radioacti- 
vated materials for investigations in chem- 
istry, biology, and physics are obvious. 
The cooperation of the National Cancer 
Institute was most helpful, especially so 
as that organization continued the assign- 
ment of Physicist D. B. Cowie, of its staff, 
to this project; in the absence of the regular 
staff of physicists of the Department, he 
and the technicians working with him are 



42 



CARNEGIE INSTITUTION OE WASHINGTON 



to be credited with a large measure of the 
progress made. 

Observatory- and field-wor\. In collab- 
oration with the University of Alaska, the 
Observatory at College was maintained 
and magnetic and auroral programs were 
initiated early in the report-year. The 
Huancayo and Watheroo magnetic ob- 
servatories continued extensive geophysical 
observations as heretofore. Cooperation at 
Apia in atmospheric electricity was con- 
cluded December 31, 1941. The recordings 
of the atmospheric-electric elements and 
earth-currents in cooperation with the 
United States Coast and Geodetic Survey 
and Bell Laboratories at the Tucson Ob- 
servatory were continued, as was the main- 
tenance of international magnetic stand- 
ards at the Cheltenham Magnetic Observa- 
tory of the United States Coast and 
Geodetic Survey. Constant contact with 
the Division of Geomagnetism and Seis- 
mology of the Survey has been mutually 
advantageous, the more so now that the 
Survey is undertaking extensive reoccu- 
pations of CIW and other stations in South 
and Central America. 

To complete the geomagnetic and au- 
roral compilations and discussions of the 
United States Antarctic Expedition of 
1940-1941, the facilities of the Department 
were extended, at the request of the United 
States Department of the Interior, for the 
whole year to R. G. Fitzsimmons and for 
five months to M. A. Wiener, of that 
Expedition. 



Cooperative work was continued with 
surveys in Africa, Australia, and New Zea- 
land and at observatories in South Africa, 
Samoa, Greenland, and Mauritius through 
the loan of CIW instruments, supplying 
of materials, and preparation of instruc- 
tions. 

Miscellaneous. Two of the retired mem- 
bers of the staff, who had contributed 
largely to the operations of the Depart- 
ment, have died. Carroll Christopher 
Ennis died November 24, 1941, after an 
enviable record of service to geomagnetism 
and oceanography. William John Peters, 
who was largely responsible for the suc- 
cessful development of the Institution's ex- 
tensive surveys at sea on the Galilee and 
the Carnegie and for many geomagnetic 
investigations, died July 10, 1942, just after 
the close of the report-year. Both these 
men were unique in their scholarly quali- 
fications and devoted unselfish service to 
science. 

The Department was fortunate in hav- 
ing on active duty three others of its re- 
tired staff — J. W. Green, A. Smith, and 
W. F. Wallis — who did much to carry on 
as replacements for younger men assigned 
to war problems. 

Although the bibliography accompany- 
ing this report shows fewer publications 
than during the preceding year, it gives 
ample evidence of the wide range of the 
activities of the staff. 



INVESTIGATIONAL AND EXPERIMENTAL WORK 
TERRESTRIAL MAGNETISM 



Those of the staff chiefly engaged at 
Washington on investigational and experi- 
mental work relating particularly to geo- 
magnetism were Fleming, J. W. Green, 
Johnston, Miss Lange, McNish, Scott, Tor- 
reson, Vestine, Wallis, and Wells. Chap- 



man at London gave constructive advice 
and made theoretical investigations which 
have proved of great value to the Depart- 
ment's program. A considerable portion of 
the time of each, in some cases almost all, 
was given to work on special analyses and 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



43 



compilations and on instruments con- 
cerned with the war effort. The following 
statements regarding the several items of 
investigation summarize only a part of 
the work actually done. 

Permanent Field 

Analysis of geomagnetic field. The in- 
vestigation of methods of field-analysis and 
use of computing-machines to facilitate 
such analysis were continued by Vestine. 
To conclude the project of field-analyses 
by integrals on the theoretical side, an at- 
tempt was made to obtain a more compact 
expression for a function giving external 
current-systems corresponding to any ob- 
served magnetic field at the Earth's surface. 
Two methods previously worked out give 
a complete and exact solution but are 
rather slow in application. This function 
is intimately associated with the height of 
electric current-systems above the Earth 
compatible with observed surface fields. 

A study was made of the world-wide 
distribution of magnetic anomalies. Large 
anomalies appear in volcanic regions, 
where rocks such as granite and basalt, 
magnetized on cooling below the Curie- 
point, are likely to be common, and con- 
sequently also in earthquake-zones. A col- 
lection was also made of material and 
charts showing locations of ferromagnetic 
mineral deposits, where magnetic anoma- 
lies may be expected. 

Reduction of field-data to mean epochs. 
The construction of new world isoporic 
charts for the epoch 1930-1935 was con- 
tinued and preliminary steps were taken 
to construct similar charts for the epoch 
1940-1945. Geomagnetic charts of the pres- 
ent epoch show large systematic errors, and 
the new isoporic charts should assist ma- 
terially in providing the more accurate 
rates of secular change needed for their 
improvement and the best use of the avail- 



able material. The isoporic charts devel- 
oped at the Department by Fisk for the 
epoch 1 920-1925 were replotted on Merca- 
tor's projection and tested for mutual con- 
sistency in the case of the isopors for 
horizontal intensity and declination. For 
declination, this method is being used in 
obtaining a compromise between the re- 
sults of Fisk and Duvall for the region 
of the Pacific Ocean. The estimates based 
on Chapman's modification of Schuster's 
curl-method (see p. 44) show marked evi- 
dence of inconsistencies, and the problem 
of adjustment of the isopors so that the 
results for horizontal intensity and dec- 
lination will be mutually consistent is be- 
ing studied. 

Tables to correct field-observations for 
post-perturbation and annual variation 
were prepared for all days of the period 
1 905-1 937. Since disturbances vary both 
in number and in intensity with time of 
year, they contribute the major part of 
an apparent annual variation. This varia- 
tion throughout low and middle latitudes 
is most marked in the geomagnetic north 
component, for which it has an amplitude 
of the order of about 10 gammas (iy = 
0.0000 1 CGS unit). 

The annual variation was derived using 
data for about 65 observatories of the Polar 
Year, 1932-1933. The results proved satis- 
factory for the geomagnetic north and east 
components, but were highly erratic for 
the vertical component except in high 
latitudes. A similar derivation was made 
for a period of 24 years for 10 stations in 
low and middle latitudes; the results for 
the vertical component were again found 
to be somewhat erratic. The geomagnetic 
north component is small near the geo- 
magnetic poles and increases rapidly equa- 
torward to a maximum at the auroral zone. 
Just outside the auroral zone this com- 
ponent diminishes rapidly with decreasing 



44 



CARNEGIE INSTITUTION OF WASHINGTON 



latitude and attains a secondary maximum 
near the equator. The geomagnetic east 
component was found to be small in all 
latitudes. The vertical component is larg- 
est near the center of the auroral zone 
and zero near the equator, where a reversal 
in sign occurs. 

The annual variation can be separated 
into two parts. One part is symmetrical 
about the equator with a minimum near 
the equinoxes, and varies with latitude in 
proportion to the annual average of dis- 
turbance in amplitude. Cynk showed that 
the remaining part is nearly sinusoidal in 
character with a period of one year, with 
minimum at the winter solstice and maxi- 
mum at the summer solstice. The annual 
variation thus comprises both an annual 
and a seasonal component. 

The annual variation varies in amplitude 
with sunspot-cycle, the amplitude for years 
of sunspot-maximum being about twice 
that for years of sunspot-minimum. 

A possible electric current-system of the 
part symmetrical about the equator closely 
resembles that corresponding to the annual 
average of the daily means of disturbance, 
if the lines of current-flow are assumed to 
flow in closed circuits in a thin layer in the 
Earth's atmosphere at constant height. 
Lines of current flow from east to west in 
all latitudes, with maximum concentration 
of current in polar regions. In the case of 
the sinusoidal part, the current-lines are 
roughly along parallels of geomagnetic 
latitude opposite in direction in the North- 
ern and Southern hemispheres, and in- 
crease in intensity from zero near the 
equator to a maximum in polar regions, 
where the variation with time of year is 
marked. This notable seasonal variation 
also gives rise to considerable distortion in 
the average current-system of geomagnetic 
disturbance. 

The development of methods for the 
reduction of field-observations to mean of 



day on a world-wide scale was continued. 
For this purpose the solar daily variation 
(Sq), disturbance daily variation (Sd), 
storm-time variation (Dst), and irregular 
disturbances (D t ) are being derived for in- 
dividual days. Using estimates based on 
graphs for two and three stations spaced 
roughly 120° and 180 apart in longitude 
in equatorial regions, the means according 
to hour of Greenwich time appear to give 
a rather good estimate of the storm-time 
variation. The estimated corrections in the 
case of Sd are less satisfactorily determined. 
In the case of S q use is being made of 
average values corrected in amplitude for 
sunspot-variation, and for daily variability 
by inspection of magnetograms at one 
station. 

Mathematical treatment of geomagnetic 
charts. Chapman continued his discussions 
of isomagnetic charts, embodying his re- 
sults in three additional papers. They 
dealt with the following subjects: "Earth- 
air electric currents and the mutual con- 
sistency of H and D isomagnetic charts"; 
"Mathematical notes on isoporic charts and 
their singular points"; "The mutual con- 
sistency of the declination and horizontal- 
intensity isoporic charts." These discus- 
sions and the methods proposed have 
already proved most useful in the revision 
of isomagnetic and isoporic charts with 
that greater accuracy required for more 
recent epochs and for use in analyzing the 
permanent field. 

Magnetic Disturbances and Cosmic 
Relations 

A study was made of the frequency and 
current-systems of geomagnetic bays, using 
extensive data of the Second International 
Polar Year, 1932-1933. The daily and an- 
nual frequencies of bays were examined for 
groups of stations in four different latitude- 
zones: (I) near the geomagnetic north 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



45 



pole; (II) the auroral zone; (III) middle 
latitudes; and (IV) the equator. The new 
results show that bays appear with about 
equal average frequency at all times of day, 
the apparent marked variations in fre- 
quency with local geomagnetic time found 
in zones II to IV being occasioned by 
a notable variation in the amplitude of 
bays with time of day. In all latitudes bays 
appear with an average amplitude greater 
at the equinoxes than at the solstices. 

Heights of the polar part of the electric 
current-system of bays were estimated in 
two different ways, for two simple assumed 
forms or models. The heights obtained 
agreed well with previous, though less de- 
tailed, results of Birkeland, Goldie, Vestine 
and Chapman, and McNish, and place the 
probable location near the E-region of the 
ionosphere. 

An approximation to the average cur- 
rent-system of bays was deduced, assuming 
the currents to be confined to a spherical 
shell concentric with the Earth, at a height 
of 150 km, and using averaged vector- 
changes of many bays taken for time of 
maximum. This current-system differs 
from that proposed for magnetic storms 
by Chapman, and subsequently considered 
by Goldie and Vestine, in that there ap- 
pears little evidence of a storm-time part 
(Dst); the current-system resembles that 
for the diurnally varying component (Sd) 
of storms, though notably distorted in 
polar regions. In these regions important 
seasonal changes in the current-distribu- 
tion were also found in individual bays. 
This simple current-system was found to 
afford a fairly satisfactory possible explana- 
tion, both qualitative and quantitative, of 
the world-wide incidence of bays in fre- 
quency and amplitude. 

Investigations by Wells of relations be- 
tween the four major magnetic disturb- 
ances of 1941 and 1942 (March 1, July 4-5, 
and September 18, 1941, and March 1, 



1942) and ionospheric changes are sum- 
marized on pages 56-57. Data for the 
great magnetic storms of the present sun- 
spot-cycle were tabulated and discussed 
by McNish. 

In cooperation with five astronomical 
observatories (Navy, Mount Wilson, Mc- 
Math-Hulbert, Climax of Harvard Univer- 
sity, and Whitin of Wellesley College) and 
with geophysical observatories of the In- 
stitution and others in Australia, Canada, 
and New Zealand, more intensive research 
on the correlation of solar, ionospheric, and 
geomagnetic disturbances was begun. 
There has already been developed a means 
of forecasting, with fair success, iono- 
spheric and magnetic disturbances for four 
to five days in advance. The results of 
these investigations are being closely co- 
ordinated with the effects on radio condi- 
tions, in cooperation with the National 
Bureau of Standards. 

The experimental investigation of the 
upper atmosphere using modulated search- 
light beams, reported upon last year (Year 
Book No. 40, pp. 66-68), had to be de- 
ferred because all the personnel engaged 
on it were on leave of absence in con- 
nection with war efforts. Meanwhile the 
searchlights and associated equipment have 
been properly housed at the Kensington 
and Washington stations. 

Cosmic-ray investigations. On behalf of 
the Institution's Committee on Coordina- 
tion of Cosmic-Ray Investigations, the 
necessary attention (Lange, Forbush, and 
Fleming) was given to the maintenance 
of CIW precision cosmic-ray meters at 
five observatories. Because of leave of ab- 
sence for war work, Forbush could devote 
only a small amount of time to the com- 
pilation and discussion of records ob- 
tained; greater responsibility had therefore 
to be taken by Miss Lange in these mat- 
ters. A notable disturbance was that co- 
incident with the magnetic storm of March 



4 6 



CARNEGIE INSTITUTION OE WASHINGTON 



i, 1942, which was reported upon by Miss 
Lange and Forbush, V. F. Hess, and 
others. The report of the Committee 
(Year Book No. 41, pp. 87-102) briefly 
abstracts the results of this study and 
others. 

Archives of Magnetic Records 

The microfilm copies of records acquired 
during the Second International Polar 
Year, 1 932-1 933, have again proved of 
great value, especially in the improvement 
of isomagnetic charts required for military 
use. 

Ennis began a complete revision of 
annual values of the geomagnetic elements 
as given in publications and reports of the 
world's observatories. Following his death, 
this compilation was completed by Scott. 
The lists show the observed and com- 
puted annual values at over 100 principal 
existing and discontinued observatories for 
declination, inclination, and horizontal, 
north-south, east-west, vertical, and total 
components of the Earth's field. These 
values will supply investigators with the 
published magnetic results as well as 
with computed values of such of the ele- 
ments as are not included in the publica- 
tions. In the case of some of the observa- 
tories — fortunately not many — there was 
evidence of a lack of accuracy in the com- 
putational or observational work; every 
effort was made to correct such errors of 
computation and to check the derivation of 
those of the seven elements and compo- 
nents which must depend upon the three 
elements usually recorded, that is, declina- 
tion, horizontal intensity, and inclination, 



or declination, horizontal intensity, and 
vertical intensity. 

Instrumental Developments 

Electromagnetic standard. Analysis of 
the absolute measurements, completely 
checked by Wallis and Scott this year, 
on the electromagnetic standard (see Year 
Book No. 40, p. 68) shows that the di- 
ameter of the coil is known to Vi part in 
a million (0.5 X io" 6 ) and that the coil- 
lengths are correct to 1 Vz parts in a million 
(1.5 X io" 6 ). The pitch of the coils varies 
less than ±2 microns. The temperature- 
coefficient was determined to be approxi- 
mately 5 parts in a million (5 X io" 8 ) per 
degree centigrade. On the basis of these 
measurements, the absolute value of the 
vertical component of the Earth's magnetic 
field at the Cheltenham Magnetic Observa- 
tory, where the instrument, when com- 
pleted, is to be installed as the standard 
of intensity, will be known to 0.5 gamma 
and the horizontal component to 0.3 
gamma. The assembly of the instrument 
must of necessity be deferred until per- 
sonnel and shop facilities can be released 
from their present war duties. 

New magnetometer design. The devel- 
opment of new and simple instruments for 
field-observations reported last year (see 
Year Book No. 40, p. 68) is being actively 
continued. 

Automatic auroral camera. As reported 
on page 77 of this report, the automatic 
auroral camera was completed and is func- 
tioning quite satisfactorily at the College 
Observatory in Alaska. 



TERRESTRIAL ELECTRICITY 



Research in terrestrial electricity was con- 
siderably reduced because of demands 
made upon the staff by the war effort. In 
geoelectricity, the data obtained at the ob- 



servatories were examined only to the extent 
required to ascertain that a high standard 
of reliability is being maintained; in at- 
mospheric electricity, aside from routine 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



47 



checks and the reduction of data, some in- 
vestigations were made by Gish, Sherman, 
and Wait, and the investigation of con- 
densation-nuclei was continued through- 
out the report-year by Research Assistant 
Marcella Lindeman Phillips. Rooney and 
Torreson were engaged throughout the 
year on war projects, and all other mem- 
bers of the section devoted varying pro- 
portions of their effort to such matters. 
Some results from this endeavor, in addi- 
tion to their primary bearing on practical 
affairs, have interest for geophysics. 

Atmospheric Electricity 

Electrical state of the atmosphere. An 
electrical charge in a portion of the at- 
mosphere or the charge on a raindrop is 
dispersed or lost at a rate depending on 
the amount of charge and the electrical 
conductivity of air. The electrical state of 
the atmosphere is also related in other ways 
to the electrical conductivity of the air, 
which in turn depends on the presence 
of ions, small electrically charged "parti- 
cles." When the latter are driven by elec- 
trical or other forces they effect a transport 
of electricity. The rate of transportation 
is proportional to the number of carriers, 
or ions, their velocity, and the load (elec- 
trical charge) borne by each carrier. The 
load is apparently the same for practically 
all the carriers, namely, one elementary 
unit of electric charge. The velocity, how- 
ever, varies widely. It depends of course on 
the driving force (electric field-strength or 
potential-gradient), but also on the nature 
of the ions, chiefly their size. The "small 
ions" in the air near the Earth have a size 
equivalent to that of a few molecules, and 
attain velocities between i and 2 cm per 
second when in an electric field of 1 volt 
per cm, but with the same driving force 
the "large ions," equivalent in size to about 
a million simple molecules, attain a ve- 



locity of only a few ten-thousandths cm per 
second. Since each of these large ions usu- 
ally carries the same amount of charge as 
a small ion, the large ions can contribute 
comparatively little to the transport of 
electricity through the air unless their 
number is very great as compared with 
that of the small ions. Though usually 
negligible in this respect, the large ions, 
or rather the entities (nuclei of conden- 
sation) from which they are formed, play 
an important role in atmospheric electricity 
because they are usually formed from the 
nuclei of condensation at the expense of 
small ions. Thus an increase in the con- 
centration of large ions entails a decrease 
in the concentration of small ions and a 
nearly corresponding decrease in the elec- 
trical conductivity of air. 

The conductivity of the atmosphere also 
depends on the rate at which small ions 
are formed. The principal recognized ion- 
forming agents in the air near the Earth 
are the cosmic radiation and radiations 
from radioactive matter in the Earth and 
in the atmosphere. 

The foregoing considerations suggested 
investigations of the following subjects: 
(a) the nuclei of condensation; (b) the 
sources from which these nuclei come; (c) 
how they are disseminated in the atmos- 
phere; (d) how they are finally lost; and 
(e) the rate of formation of small ions in 
the atmosphere by radiations from radio- 
active matter in the Earth. Other investi- 
gations included analyses and interpreta- 
tions of various aspects of the registrations, 
obtained at the Institution's magnetic ob- 
servatories, of the several atmospheric-elec- 
tric elements. 

Rate of ion-formation. Because of the 
following observed facts, it has been ques- 
tioned whether the rate of ion-formation 
by known ionizing agents is adequate to 
account for the number of small ions in 
the lower atmosphere, (a) The rate of 



4 8 



CARNEGIE INSTITUTION OF WASHINGTON 



ion-formation inside chambers with thick 
walls (3-mm brass) is several times greater 
than that to be expected on the basis of 
the values reported by Evans and Good- 
man for the radioactive material in rocks. 
(b) The variation of this rate with time, 
in either thin- or thick-walled chambers, 
shows differences with respect to character 
and amplitude which would hardly be in- 
ferred from available information regard- 
ing the kind and quantity of radioactive 
matter in the Earth (Gish). General plans 
for the solution of the problem which 
results from (a) were described by Hess 
(Terrestrial Magnetism, vol. 46, pp. 409- 
415, 1941). The apparatus designed by 
Gish for use with a null method was 
constructed in the instrument-shop of 
the Department, precise determinations 
of the constants were made by Sherman, 
and a preliminary investigation of the 
general performance of the equipment 
was made by Gish and Sherman. The 
chief results of the latter are: (a) Contact- 
potentials are entirely negligible; (b) the 
rate of ionization from a known amount 
of radium is in satisfactory agreement 
with values found by others with compar- 
able equipment; (c) in a laboratory room a 
rate of ionization of 6.8 ion-pairs per cubic 
centimeter per second was found; (d) 
there appears to be no appreciable amount 
of radioactive matter in the material 
(brass) from which the ionization-cham- 
bers are made — a favorable but unexpected 
circumstance; (e) ionization by secondary 
radiation, of low penetrating power, ex- 
cited in the walls of the chamber by 
gamma radiation is apparently revealed by 
this method of investigation when the 
chambers are exposed to the radiations 
from a specimen of radium, but no such 
effect is definitely indicated by exposure 
to the radiation from the radioactive mat- 
ter normally present in the walls, etc., of 
the room. Further investigation is re- 



quired to ascertain the extent to which 
this result must be taken into account in 
the final interpretation. These ionization- 
meters are to be used by Hess and associ- 
ates at Fordham University to ascertain 
whether the low values recently reported 
for the radioactive content of rocks and 
other earth-materials can be verified by 
this method. 

Sources of condensation-nuclei. Many 
nuclei are supplied to the air by boiling 
water; their number increases rapidly 
from the time when bubbles begin to rise 
(Gish, Sherman, Phillips). The steam- 
plume from a tea-kettle contains many 
more water-droplets than the number of 
nuclei normally present in air. This in- 
crease is probably due partly to the break- 
ing of water-films — nuclei are formed 
when water and other liquids are atomized. 

Nuclei are produced in abundance when 
drops of water fall upon a hot metal sur- 
face. Metal while being heated below 
incandescence gives off nuclei for a few 
minutes, provided this property has not 
been destroyed by heating some days 
previously. 

Nuclei, at least such as can be detected 
with an Aitken nuclei-counter, are not 
given off from the undisturbed surface 
of most liquids at normal temperature and 
pressure. When these liquids are atomized, 
however, an appreciable number of nuclei 
are produced. Nuclei may be formed from 
the molecules of various vapors by suffi- 
cient sudden cooling. When the latter oc- 
curs, the concentration is sometimes so 
great, and consequently the size of the 
drops formed in the counter so small, that 
nuclei thus produced may escape detec- 
tion. Earlier observations (Wait) indicated 
that nuclei are numerous in exhaled air, 
but current observations (Phillips) failed 
to confirm this. No explanation for these 
divergent results was found. 

Dissemination of condensation-nuclei. 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



49 



The dissemination of condensation-nuclei 
in the air obviously depends chiefly on 
the motion and mixing of the air. Specific 
information about the rate and manner of 
dissemination in a closed room was re- 
quired for an investigation of the rate at 
which nuclei are lost from the air. The 
rate of dissemination was found (Phillips) 
to be such that in the quiescent air of a 
closed bedroom the nuclei became uni- 
formly distributed from floor to ceiling in 
about one-half hour after introduction 
from an atomizer or other source; no evi- 
dence was found of a distribution of nuclei 
in strata such as has been reported by 
Landsberg. 

The rate of loss of nuclei from the air 
or the rate of decrease in the number of 
nuclei in the air may be attributed to 
either or both of the following processes: 
(a) Nuclei may coalesce and form larger 
entities which settle out of the air; (b) they 
may reach the Earth's surface or the walls 
of rooms, etc., simply by diffusion, and 
adhere to the surface of these. The rate 
of diminution in the concentration of 
nuclei should be proportional to the square 
of the concentration in the first case and 
simply proportional to the concentration in 
the second case. If both these processes are 
active, the diminution may at the start, 
when the concentration is large, vary more 
nearly as the square, and later as the first 
power of the concentration. This tendency 
was evident in a fair proportion of the 
series of observations (Phillips) made in 
closed rooms, and in chambers of much 
smaller volume, using nuclei from dif- 
ferent sources. The diminution, however, 
was found to depend to some extent on the 
nature of the nuclei, that is, on the source 
of supply. The diminution-rate is greater 
for nuclei formed from the more volatile 
liquids, and those produced by "condensa- 
tion upon molecules" appear to be less 
stable than others. 



Method of counting nuclei. The method 
of counting nuclei received some further 
attention (Gish, Phillips). The claim has 
been made that the small ions in the air 
are "counted" in the Aitken pocket nuclei- 
counter. Further evidence against this 
claim was obtained in an experiment de- 
signed for another purpose, namely, to 
ascertain whether in the air there are 
nuclei of different classes with respect to 
their effectiveness in condensation. In or- 
der to form a droplet about a nucleus, 
the air in the counting chamber (saturated 
with water-vapor) is suddenly expanded 
and consequently cooled. Less expansion 
(a smaller ratio of expanded volume to 
initial volume) should be required for 
nuclei which have a greater than for those 
which have a smaller affinity for water. 
Within the range of expansions (expan- 
sion-ratios 1.05 to 1.35) obtainable without 
modifying the counter, the total number of 
droplets which could be precipitated from 
a sample of room air containing nuclei 
did not vary significantly; that is, all en- 
tities which serve as nuclei of condensation 
in this counter can be precipitated by very 
little expansion, or very little supersatura- 
tion, of the air. It is therefore concluded 
that all these entities are about equally 
effective as condensation-nuclei and that 
small ions are not counted. All nuclei 
are not precipitated, however, by the first 
expansion of a sample; about 60 per cent 
of those present just before an expansion 
are precipitated when an expansion-ratio 
of 1.30 is used, and about 40 per cent for 
an expansion-ratio of 1.05 (at average room 
temperature). But if the sample is ex- 
panded repeatedly until no more droplets 
are formed, the total number of droplets 
obtained from comparable samples appar- 
ently does not depend on the expansion- 
ratio. This finding supports the view that 
repeated expansions are required in order 
to remove all nuclei and that the sum of 



50 



CARNEGIE INSTITUTION OF WASHINGTON 



the droplets counted in these expansions 
is the best measure of the concentration 
of nuclei. In the normal practice with this 
type of counter, when the largest expan- 
sion-ratio (1.35) is used, five successive 
expansions are required to precipitate 99 
per cent of the nuclei; but for the smallest 
expansion-ratio used in these experiments 
(1.06), ten expansions are required to pre- 
cipitate the same proportion of the nuclei. 
Obviously the tedium of counting is re- 
duced by using the larger expansion-ratio. 
Little further improvement in this direc- 
tion could be realized, however, by pro- 
viding the counter with a longer pump, 
thus making larger expansion-ratios avail- 
able, because the stage where condensation 
on small ions sets in is apparently reached 
when expansion-ratios slightly greater than 
that now available are used. 

Modifications in atmospheric-electric 
elements caused by condensation-nuclei. 
Condensation-nuclei in the atmosphere at 
the Huancayo Magnetic Observatory effect 
extraordinary modifications in the atmos- 
pheric-electric phenomena observed there. 
This was first inferred from a study (Gish, 
Year Book No. 37, p. 15) of the registra- 
tions made at that Observatory of the at- 
mospheric-electric and meteorological ele- 
ments. The three important modifications 
of the electrical phenomena are: (a) The 
measured electric current, which flows 
from air to Earth, is certainly less than one- 
half that which would be expected at such 
a high altitude (11,000 feet), (b) The con- 
tribution by negative ions to the electric 
conductivity of air at night is often greater 
than that by positive ions at this place, 
whereas the contribution by positive ions 
usually is the greater at other places, (c) 
The diurnal variation of potential-gradient 
and of air-conductivity is remarkable for 
the large and abrupt change (four- to five- 
fold) which occurs between o6 h and o8 h 
almost daily during the dry season. 



A tentative explanation of these features 
proposed by Gish is briefly as follows: 
Regular observations (counts) of nuclei 
at o8 h each day had shown that the nuclei- 
concentration is much greater than is to 
be expected, considering the immediate en- 
vironment of the Observatory. Hence the 
nuclei are thought to come from a distant 
source and to be carried by the more gen- 
eral air-circulation. They are introduced 
into the air near the surface at the Ob- 
servatory by turbulent stirring (eddy-dif- 
fusion) when that process is active. When 
the lower air becomes stable, however, 
which is most likely at night, turbulent 
mixing of this with the higher stratum be- 
comes less effective, and the rate at which 
nuclei are supplied to the lower air is re- 
duced. Then the nuclei-concentration near 
the surface decreases and the air-conduc- 
tivity increases. In the morning after sun- 
rise, when the air in the lowest stratum 
becomes sufficiently heated, mixing of the 
lower with the higher overrunning air sets 
in and nuclei are again supplied to the 
surface-air from above. The ensuing in- 
crease in nuclei-concentration entails a de- 
crease in air-conductivity. If the stable 
lower stratum which develops at night is 
shallow (say 100 meters), and the nuclei- 
concentration in the general circulation 
does not vary from night to day, the elec- 
trical resistance of a vertical air-column 
from the Earth to a height of some tens 
of kilometers is modified very little by the 
change in conductivity from night to day. 
Hence only a very small corresponding 
change in air-earth current is to be ex- 
pected and the potential-gradient should 
vary inversely as the conductivity. The 
recorded data are in accord with these ex- 
pectations. 

The relation between values of negative 
and positive conductivity observed at night 
(the former exceeding the latter) is a 
simple consequence of the decrease of total 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



51 



conductivity with altitude in the air near 
the Earth's surface. This observation also 
indicates that the lower stratum extends 
to a comparatively small height. Rough 
estimates, by two independent methods, 
had indicated that it is probably not less 
than 10 meters nor more than 100 meters. 

The height to which the variation of 
conductivity at the surface extends was 
estimated (Wait) during the present year 
by a more extensive examination of the 
electric data. Not only was the low value 
previously estimated for the height of the 
lowest nighttime stratum verified by this 
examination, but it was also found that the 
average diurnal changes in air-conductivity 
at this place are confined to a shallow 
stratum. 

On 15 days in August 1941 special ob- 
servations of the nuclei-concentration were 
made (Jones, Ledig) at the Huancayo 
Magnetic Observatory at o6 h and of" in 
addition to the regular observations at o8 h , 
in order to ascertain whether nuclei are 
as scarce at night as is implied by the pro- 
posed explanation outlined above. These 
observations show a contrast in nuclei-con- 
centration considerably greater than that 
in conductivity. The average count of 
nuclei at o8 h was 10.9 times that at o6 h , 
whereas the average conductivity at o6 h 
was 3.6 times that at o8 h . The proportional 
change in concentration of nuclei is larger, 
as compared with that in conductivity, 
than is usually found at other places, but 
studies of the regular nuclei-counts at o8 h 
at Huancayo (Gish, Torreson, Year Book 
No. 38, pp. 74-75) revealed a comparable 
tendency in the variations from day to 
day. Such a tendency may arise in several 
ways. The one which now seems most 
plausible (Gish) is that the nuclei in the 
lower air at night are of different charac- 
ter from those present in daytime. The 
former, perhaps chiefly of local origin, 
"combine" more readily with the small 



ions in the air than do the latter, which 
doubtless come from a very different dis- 
tant source. The rate of combination be- 
tween the small ions and the nuclei from 
the distant source appears to be notably 
smaller than in any other case thus far 
reported. In brief, these early-morning ob- 
servations of nuclei have not only cor- 
roborated the proposed explanation for 
three outstanding aspects of atmospheric 
electricity at Huancayo, but have also 
shed light upon some other matters, for 
example the rate of combination between 
nuclei and small ions. 

Condensation-nuclei in the atmosphere 
at the Watheroo Magnetic Observatory 
modify the atmospheric-electric elements 
in a manner different from that at Huan- 
cayo, but no less interesting. This fact was 
brought out more clearly than heretofore 
by analyses made by Wait. 

The method of analysis is based upon the 
fact that nuclei and some other agents 
generally affect the electric state of the 
atmosphere to a much greater degree over 
land than over sea. Accordingly the at- 
mospheric-electric data obtained on cruises 
of the Carnegie have frequently been used 
as a standard for comparison with other 
data. These studies have indicated the 
desirability of making a more precise com- 
parison using data observed simultaneously 
on land and at sea. 

Material for such a comparison was ob- 
tained at the Watheroo Magnetic Observa- 
tory and on board the Carnegie during 
1928-1929. Thus far the data for 42 fair- 
weather days in November-December 1928 
and January-February 1929 have been 
compared (Wait). Of these 42 days, 17 
are classed as "smoky" and 25 as "non- 
smoky" at Watheroo. The concentration 
of nuclei is of course much greater on 
days in the first than on days in the 
second category, hence the terms "smoky" 
and "non-smoky" connote a relatively large 



52 



CARNEGIE INSTITUTION OF WASHINGTON 



and a relatively small concentration of 
nuclei, respectively. 

The essential features of the data for po- 
tential-gradient and for air-earth current 
are conveniently expressed by the Fourier 
series, y = ~y + S(#« cos nQ + bn sin «0), 
where G in degrees is 15 times the time in 
hours counted from Greenwich midnight. 
The coefficients of the first four harmonics 
are listed in table 1. 



the latter method, but the diurnal varia- 
tion of these values obtained by the for- 
mer was of about the same character as 
that for values obtained by the latter 
method. The average was 4 per cent lower 
for non-smoky and 14 per cent lower for 
smoky days; ranges to 9 and 8 to 25 
per cent, respectively. 

An inspection of table 1 discloses that, 
although the mean potential-gradient at 



TABLE 1 
Comparison of Fourier coefficients for potential-gradient (X) in volts per meter and 

AIR-EARTH CURRENT (/') IN IO" 7 ESU AT SEA AND AT WaTHEROO MAGNETIC OBSERVATORY 



Condition at 
Watheroo 



Ele- 
ment 


Mean 






Fourier coefficients 






GMT 

MAXI- 
MUM 

(h) 


24-hr. 


12-hr. 


8-hr. 


6-hr. 


ai 


61 


02 


62 


03 


b 3 


04 


64 



Ratio* 

(Ci/Cl) 



At sea, Carnegie 



Smoky 

Non-smoky . 



X. . 


146 


- 8.9 


-22.5 


-5.2 


-0.9 


-1.2 


-1.6 


+ 1.7 


+ 1.9 


16.6 


i. . . 


9.7 


-0.48 


-1.62 


-0.44 


-0.10 


-0.04 


-0.05 


+0.16 


+0.04 


16.8 


X. . 


130 


- 7.7 


-22.9 


-7.0 


-1.8 


-0.4 


-2.0 


0.0 


+ 1.2 


16.8 


i. . . 


8.8 


- 0.51 


- 1.57 


-0.46 


-0.14 


-0.01 


-0.14 


-0.01 


+0.06 


16.9 



0.22 
0.26 
0.30 
0.29 



On land, Watheroo Magnetic Observatory 



Smoky 

Non-smoky . 



X. . 


123 


- 8.7 


-33.8 


-6.7 


-7.2 


-5.4 


-3.8 


+ 1.9 


+ 1.9 


17.0 


i. . . 


9.1 


+ 0.33 


- 0.29 


+0.02 


+0.16 


+0.05 


-0.37 


0.00 


+0.08 


21.3 


X. . 


89 


-13.6 


-14.9 


-2.3 


+ 1.4 


+ 1.6 


-2.9 


+ 1.2 


-0.6 


15.2 


i. . . 


8.6 


- 0.14 


-1.07 


-0.20 


+0.20 


+0.11 


-0.12 


-0.03 


0.00 


17.5 



0.28 
0.37 
0.13 
0.26 



* Ratio of amplitudes (a/ci) = (V02 2 + b^/Voi* + 612). 

The values used for air-earth current in 
this analysis are the products of corre- 
sponding individual values of potential- 
gradient and of total air-conductivity, not 
the products of corresponding mean values. 
The importance of calculating values of 
air-earth current in this way was again 
emphasized (Year Book No. 40, p. 76) 
by a comparison of the values calculated 
both ways with data for 108 days at 
Watheroo. Nearly all values calculated by 
the former, more exact but more tedious, 
method were lower than those obtained by 



sea was significantly greater than at 
Watheroo on both classes of days, the mean 
air-earth current-density was nearly the 
same at the two places. On smoky days 
the character of the diurnal variation of 
current differs between land and sea more 
than that for other corresponding elements 
— the maximum for the 24-hour harmonic 
occurs 4.5 hours later on land than at sea 
and this component is less prominent. 
Some of the other differences, however, 
are also significant. These differences are 
revealed more clearly, and in a form more 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



53 



susceptible of interpretation, by an ex- 
amination of the diurnal variation in the 
ratio of air-earth current at sea to air-earth 
current on land for corresponding hours. 

The electrical resistance of a vertical 
column of air of i cm 2 cross-section, ex- 
tending upward from the Earth to the 
level of great conductivity (some tens of 
kilometers), is directly proportional to the 
ratio of air-earth current at sea to that on 
land. This "columnar resistance" has a 
definite daily period, being smaller in day- 
time than at night and essentially of the 
same character as that determined previ- 
ously from nonsimultaneous data on land 
and at sea (Year Book No. 40, p. 77). 

The average columnar resistance on 
smoky days is greater than that on non- 
smoky days, but the minima are nearly 
equal; thus the difference on the two types 
of day occurs chiefly at night. The data for 
the nine Februaries from 1926 to 1934 show 
an average resistance 20 per cent greater 
for smoky than for non-smoky days: the 
minimum excess on smoky days was 11 
per cent and the maximum 30 per cent. 

An explanation (Wait) of the variation 
in columnar resistance at Watheroo on 
smoky days is that smoke, and the asso- 
ciated condensation-nuclei, are introduced 
into the atmosphere principally at night 
and dispersed to a height sufficient to in- 
crease the columnar resistance and reduce 
the air-earth current, as observed. Smoke 
occurs almost exclusively in the summer 
months (November to February) and at 
night. This agrees with the observed 
responses in the registrations of potential- 
gradient and air-conductivity. Days in 
summer on which smoke is observed do 
not differ appreciably from those without 
noticeable smoke in respect to wind- 
velocity, wind-direction, or air-tempera- 
ture. Disturbances caused by smoke ham- 
per investigations of the more general 



aspects of atmospheric electricity, but re- 
veal several features of geophysical interest. 
The height to which smoke of local 
origin rises at Watheroo on the average 
summer day can be estimated roughly 
from the change in columnar resistance, 
assuming that the air-conductivity as af- 
fected by smoke is uniform from the 
Earth's surface up to a definite height. The 
height thus estimated (Wait) from simul- 
taneous observations on land and at sea 
for smoky days is 1.5 km, and the height 
estimated from the much more extensive 
data for Februaries of 1926-1934 is 1.0 km. 
For non-smoky days the estimated effective 
height of the nuclei-bearing layer is 1.6 km 
for both groups, and there is no evidence 
of appreciable changes during the day. 
By the method used in estimating the 
effective height of the nuclei-bearing lower 
stratum, estimates are also obtained for 
the part contributed to the columnar re- 
sistance by atmosphere above that height. 
The point of interest in the latter is that 
that portion of the columnar resistance 
is apparently the same on smoky as on 
non-smoky days and is also essentially 
the same as that for the corresponding 
region of the atmosphere derived by 
Gish and Sherman from air-conductivity 
data registered on the stratosphere flight 
in November 1935. This indicates that the 
air above the estimated effective height 
is not usually contaminated by nuclei com- 
ing from the Earth. The conclusions are: 
(a) that, on the average, at Watheroo nu- 
clei arising from the Earth are distributed 
throughout a layer of air extending from 
the Earth upward to an effective height 
of at least 1 km, and generally not be- 
yond this; (b) that this height does not 
vary much during the day; and (c) that 
it is about the same on smoky as on non- 
smoky days. The last conclusion is con- 
sistent with the observation, already men- 



54 



CARNEGIE INSTITUTION OF WASHINGTON 



tioned, that smoky and non-smoky days, 
on the average, have the same meteorologi- 
cal characteristics. 

The question of dissemination of nuclei 
by wind at Watheroo is apparently clari- 
fied by results obtained from a statistical 
examination (Wait) of potential-gradient 
and wind-velocity data for the months of 
January, February, and March 1926-1934: 

(a) On non-smoky days the average po- 
tential-gradient increases from 87 volts per 
meter for zero wind-velocity to 105 volts 
per meter for a wind-velocity of 5 miles 
per hour, and for higher velocities there is 
little further change in potential-gradient; 

(b) on smoky days the average potential- 
gradient increases from 217 volts per meter 
for zero velocity to a maximum of 225 
volts per meter for a velocity of 2 miles per 
hour, and then gradually diminishes to 
about 180 volts per meter for a velocity 
of 12 miles per hour. The concentration 
of nuclei doubtless varies in a similar man- 
ner. The interpretations are: (a) that on 
days of both classes nuclei are brought into 
the more immediate vicinity of the Observ- 
atory by wind, but in greater concentration 
on smoky days than on non-smoky days; 
(£>) that the source of the nuclei on non- 



smoky days is probably more distant and 
spread over a wider area than that for 
smoky days; (c) that the source of the 
nuclei for smoky days is confined to a 
limited area which is probably not many 
miles from the Observatory. The last is 
consistent with the observation that most 
of the smoke noticed at Watheroo comes 
from bush-fires. Some wind is required to 
bring smoke to the Observatory, but since 
wind-turbulence increases with wind-ve- 
locity, the smoke is dispersed more rapidly 
at the higher wind-velocities. Under the 
joint action of these two factors the density 
of smoke (or concentration of nuclei) at 
the Observatory may be expected to in- 
crease with wind-velocity for low velocities, 
reach a maximum, and then decrease with 
further increase of velocity. 

Cooperation and consultation. On the 
occasions of several visits at the Depart- 
ment and through correspondence, mem- 
bers of the staff profited from stimulating 
discussions of current problems with Pro- 
fessor Victor F. Hess, of Fordham Uni- 
versity. Gish served on the Subcommittee 
on Lightning Hazards to Aircraft of the 
National Advisory Committee for Aero- 
nautics. 



INVESTIGATIONS OF THE IONOSPHERE AND ITS RELATION TO 
PROBLEMS OF GEOMAGNETISM 



The external part of the Earth's mag- 
netic field arises from electric current- 
systems which probably circulate in the 
ionosphere. Detailed and accurate knowl- 
edge of ionospheric characteristics there- 
fore provides a basis for extending and 
evaluating analyses of the external part 
of the Earth's magnetic field. 

Early theoretical work by Gauss, which 
was later extended by Stewart and Schus- 
ter, required current-systems in the Earth's 
outer atmosphere to explain certain ob- 
served variations in geomagnetism. It was 



argued that such current-systems could 
arise in highly ionized regions far above 
the Earth. Years later, when Marconi per- 
formed his famous demonstration of long- 
distance radio communication between 
England and Newfoundland, Kennelly 
and Heaviside independently proposed 
that radio waves are reflected back to Earth 
by a highly ionized region or layer in our 
outer atmosphere. Here we have the first 
link between geomagnetism and radio 
wave-propagation through their mutual 
dependence upon the ionosphere. 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



55 



The original experimental determination 
of the ionosphere was made in 1925 by 
Breit and Tuve, of the Department of 
Terrestrial Magnetism, with the generous 
assistance of Taylor at the Naval Research 
Laboratory. They developed the pulse-and- 
echo technique which is now widely 
adopted for ionospheric studies. Simul- 
taneously Appleton and Barnett in Eng- 
land obtained independent evidence of the 
ionosphere with a wave-interference meth- 
od. The active interest of the Depart- 
ment in the subsequent development and 
application of ionospheric research has 
been maintained largely because of the im- 
portant contributions to knowledge of the 
Earth's magnetic field which are made pos- 
sible by this method of attack. 

Radio apparatus provides our only 
means of exploring the ionosphere, which 
extends from about 40 to 400 miles above 
the Earth. Short pulses of radio-frequency 
energy are transmitted. These signals pen- 
etrate through the atmosphere until they 
encounter concentrations of ions and elec- 
trons of sufficient density to bend them 
around and return them to Earth. The 
recorder measures time-interval between 
signal and "echo." This provides values of 
virtual height of the reflecting region. For 
example, a signal reflected from a layer 
100 km above the Earth travels an over- 
all distance of 200 km, which requires 
transit time of just two-thirds of one- 
thousandth of a second (0.00067 sec). 

Waves of higher frequency are more 
penetrating and require greater concen- 
trations of electrons for reflection. Waves 
of still higher frequencies are not returned 
to Earth, since the ionosphere does not con- 
tain sufficient concentrations of charges to 
reflect these signals. Complete radio ex- 
ploration of the ionosphere is accomplished 
with apparatus which automatically sweeps 
over a wide range of frequencies and pho- 



tographically records the heights of the 
reflected signals. Equipment for this pur- 
pose has been developed by the Depart- 
ment, and the continuous operation of 
these units in the field is providing a solid 
foundation for detailed analyses of geo- 
magnetic and related phenomena. 

Field-Operations 

The three complete automatic multi- 
frequency ionospheric recorders designed 
and constructed at the Department of Ter- 
restrial Magnetism are now in continuous 
operation at the Huancayo (Peru) Mag- 
netic Observatory, the Watheroo (Western 
Australia) Magnetic Observatory, and the 
College (Alaska) Observatory. This ap- 
paratus sweeps through a frequency-range 
from 16.0 to 0.516 Mc/sec and automati- 
cally records the apparent height of iono- 
spheric echoes. One frequency-sweep is 
completed every 15 minutes. The appa- 
ratus consists of transmitter, receiver, con- 
trol-units, recorder, and power-supplies. 
Transmitter and receiver are automatically 
interlocked so that no separate tuning of 
receiver is necessary. In effect, one variable 
oscillator is used for both transmitter and 
receiver. 

The normal requirements for power un- 
der operating conditions amount to about 
one kilowatt. At the observatories in Peru 
and Australia, power is obtained from 
Diesel generators. These units provide 
direct current for operation of rotary con- 
verters which in turn supply alternating 
current for the radio apparatus. Each ro- 
tary converter is accurately controlled to a 
frequency of 60 cycles per second by means 
of a precise tuning-fork. Similar provi- 
sions for independent power are made at 
the College Observatory, although the 
commercially available power-supply has 
been found to be generally satisfactory. 
The installation at each observatory oper- 



56 



CARNEGIE INSTITUTION OF WASHINGTON 



ated continuously throughout the report- 
year except for minor interruptions neces- 
sary for maintenance and adjustments to 
the apparatus. The equipment at Huan- 
cayo has been operating since November 

1937, the recorder at Watheroo since May 

1938, and the apparatus at College since 
June 1941. 

Analyses of Data 

In general, the results of recordings at 
each observatory indicate trends which 
parallel the present downward trend of the 
cycle of sunspot-activity. The E-, Fi-, and 
F 2 -region critical frequencies at Huancayo 
and Watheroo observatories are slightly 
lower than during 1940. This downward 
trend is expected to continue for another 
year or two. Analyses show that average 
annual electron-density of the F2-region 
measured at noon at Huancayo Magnetic 
Observatory was about 50 per cent greater 
during the years of maximum numbers of 
sunspots (1937 and 1938) than during 1941. 

Publication of detailed summaries of 
ionospheric data was discontinued early in 
1942. This action was taken following 
specific request by governmental agencies, 
in view of important applications of iono- 
spheric data to war problems. 

Following is a discussion of ionospheric 
recordings during several intense magnetic 
storms: 

March 1, 1941- The ionospheric conditions 
during the magnetic storm of March 1, 1941 
were discussed in some detail in the last an- 
nual report. Further analyses have shown 
an unusual effect which was not remarked 
in earlier analyses. Following the conclu- 
sion of the severe magnetic disturbance, 
at about 23 11 30 111 GMT, March 1, electron- 
densities in the F 2 -region of the ionosphere 
decreased very rapidly and simultaneously 
at both Huancayo and Watheroo. At 05 11 
oo m GMT, March 2, the F 2 -layer critical 
frequencies at both locations averaged more 



than 5 Mc/sec below the normal mean hourly 
value. After 05 11 oo m a recovery in the di- 
rection of normal was noted. This recovery 
was rather gradual, reaching normal values 
about 12 11 oo m GMT, March 2. Since iono- 
spheric characteristics at widely separated 
points such as these frequently show no di- 
rect relationships, it is felt that an occurrence 
of this nature is worthy of especial note. The 
extent of the subnormal ionization recorded 
at each observatory would seem to preclude 
any possibility of its being a mere coincidence. 
This view is substantiated by the facts that the 
decrease in each case started after the end 
of the storm, the minimum values were 
reached simultaneously, and the trends back 
to normal, as well as the times of reaching 
normal, were in complete agreement. 

July 4-5, 1941. It will be recalled that the 
magnetic storm of July 4—5, 194 1 was rela- 
tively mild from 03 11 45 m GMT, July 4, to 
about 05 11 oo m , July 5. The period of greatest 
disturbance was recorded between 05 11 oo m 
and 24 11 oo m , July 5, the interval around 
jyh 0Q m b e i n g tne mos t; disturbed. At Huan- 
cayo and at Watheroo the ionospheric dis- 
turbances during the initial phase of the 
storm were relatively insignificant. At 05 11 
oo m GMT, July 5, however, electron-densities 
at Huancayo took a sharp drop to subnormal 
values. For the duration of the disturbance 
electron-densities were far below normal, 
and it is again interesting to note that the 
lowest values were recorded several hours 
after the ending of the magnetic disturbances. 
Normal conditions were reached about 12 
hours after the end of the magnetic storm. 

At Watheroo electron-densities jumped to 
values well above normal at 05 11 oo m GMT, 
July 5, but immediately dropped off and con- 
tinued at subnormal levels for the period of 
the disturbance. As at Huancayo, so at 
Watheroo ionospheric conditions did not re- 
turn to normal until about 12 hours after 
the end of the storm. The relative degree of 
disturbance, however, was much smaller at 
Watheroo than at Huancayo. 

September 18, 1941. Detailed comparisons 
of ionospheric effects at the observatories 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



57 



during the magnetic storm of September 18— 
19, 194 1 were handicapped to some degree by 
the severity of the disturbance, which pro- 
duced complete disappearance of echoes for 
several hours at Huancayo. In general, the 
recordings at Huancayo showed extensive os- 
cillations and rapid changes in maximum 
electron-density of the F 2 -region. These 
changes were sufficient to produce peaks and 
troughs above and below normal values. 
However, the extent of deviation from normal 
was not considered especially significant on 
September 18. Probably the most important 
feature at Huancayo was the recording of ab- 
normally high electron-densities between 12 11 
oo m and 24 11 oo m GMT, September 19. Dur- 
ing this interval critical frequencies of the 
Fo-region were frequently as great as 4 
Mc/sec above the normal value. 

At Watheroo ionospheric conditions were 
not greatly disturbed on September 18 ex- 
cept for a short period around i2 h oo m GMT, 
when abnormally high electron-densities were 
recorded. For all of September 19, however, 
F 2 -region electron-densities were below nor- 
mal. During the first 9 hours of September 19 
critical frequencies were more than 3 Mc/sec 
lower than average. After the end of the 
disturbance a downward trend continued for 
several hours before the recovery-phase. Nor- 
mal conditions apparently were reached about 
8 hours after the end of the storm. 

March 1, 1942. Preliminary analyses of 
ionospheric conditions during the moderately 
severe magnetic disturbance of March 1, 1942 
have been undertaken. Unfortunately the 
records at Huancayo are not complete for the 
interval, because of maintenance and adjust- 
ments to the apparatus. No definite remarks 
may therefore be made concerning the iono- 
spheric reaction at Huancayo during this 
disturbance. At Watheroo, however, Fa- 
region electron-densities were subnormal prior 
to the commencement of the storm, at 07 11 
30™ GMT, March 1. The increase in mag- 
netic disturbance was associated with a rapid 
increase in electron-density to a peak at 
about 13 11 oo m . This was followed by a 
gradual downward trend to normal values, 
which were maintained for the duration of 



the storm. The disturbance ended about 05 11 
oo m , March 2, following which the charac- 
teristic drop to low values and the gradual 
rise back to normal was observed. It will be 
recalled that this same effect has been noted 
following other periods of magnetic disturb- 
ance. No unusual ionospheric effects were 
noted which might form a basis for further 
examination in view of the pronounced de- 
crease in cosmic-ray intensity which was re- 
ported (see Year Book No. 41, pp. 94-95). 

Radio Fade-Outs 

The sudden ionospheric disturbances 
which produced short-period radio fade- 
outs at Huancayo and Watheroo during 
the calendar year 1941 are shown in tables 
2 and 3. No significance is attached to the 

TABLE 2 

Fade-out summary, Huancayo Magnetic 
Observatory, 1941 





75° WEST MERIDAN TIME OF 


Maxi- 
mum 


Date 


Start 


End 


Maxi- 
mum 


ABSORP- 
TION 

(Mc/sec) 


April 3 

July 3 

July 5 

July8 

August 20 

October 30.. . 
December 26 


h m 

10 45 

11 00 
10 45 
10 45 
10 57 
17 15 
09 49 


h m 

11 30 

12 15 
12 15 

11 45 

12 08 
18 45 
10 46 


h m 

11 00 
11 45 
11 30 

10 45 

11 53 
18 00 
10 05 


* 
* 
* 
* 

6.1 
1.3 
9.5 



* Maximum absorption not reported. 

fact that Watheroo recorded nearly twice 
as many fade-outs as did Huancayo. Mag- 
netic records during these occurrences were 
examined for unusual pulses or bays, 
which are frequently associated with the 
ionospheric disturbances. No significant 
coincidences were noted during the pre- 
liminary investigation. This is probably 
because most of the fade-outs were rela- 
tively mild and many occurred during 
magnetically disturbed periods, which 



5* 



CARNEGIE INSTITUTION OF WASHINGTON 



mask out the small magnetic effects as- 
sociated with fade-outs. 



TABLE 3 

Fade-out summary, Watheroo Magnetic 
Observatory, 1941 





120 


' EAST MERIDIAN TIME OK 


Maxi- 














mum 


Date 












absorp- 




Start 


End 


Maxi- 
mum 


tion 

(Mc/sec) 




h 


m 


h 


m 


h m 




January SO. . . 


12 


45 


13 


45 


13 08 


4.3 


February 28. . 


07 


45 


09 


30 


08 00 


4.0 


February 28. . 


17 


so 


18 


15 


17 45 


>9.0 


March 3 


16 


30 


17 


00 


16 40 


5.0 


July 1 


12 


30 


IS 


55 


13 10 


2.4 


July 2 


10 


25 


11 


30 


10 57 


4.8 


July 9 


10 


45 


11 


50 


11 40 


2.0 


August 2 


08 


SO 


13 


00 


09 00 


2.05 


September 15 


IS 


15 


14 


15 


14 00 


2.7 


September 18 


10 


15 


11 


10 


10 so- 
il 00* 


>7.5 


September 19 


09 


SO 


10 


20 


09 SO- 
10 15* 


>4.0 


September 20 


10 


so 


11 


35 


10 so- 
il SO* 


>6.3 


September 21 


10 


30 


11 


05 


10 so- 
il 00* 


>6.7 


September 23 


10 


00 


11 


05 


10 00- 
11 00* 


>7.0 


November 24 


08 


45 


10 


45 


09 45 


2.1 



* No echoes during this period. 

Developmental and Experimental Work 

Practically all instrumental develop- 
ments and experimental work were carried 
out in connection with war work and in 
cooperation with our armed services. 

The automatic camera for recording of 
aurora at the College Observatory was 
completed. Tests of this unit at tempera- 
tures down to 20° F below zero were con- 
ducted in the low-temperature rooms of 
the National Bureau of Standards. Since 
installation at College, this recorder has 
been in continuous operation. Preliminary 
reports from the Observatory indicate that 



high correlation between auroras observed 
directly overhead and significant iono- 
spheric phenomena may be expected. 

The constant-voltage controllers for use 
at observatories were tested on the main 
generator at the Department. These units 
are now in operation at the observatories, 
and the high degree of constancy of volt- 
age obtained by their use has resulted in 
improved recording. 

Cooperative Activities 

The unique position maintained by this 
Department as a result of the development 
and continuous operation of automatic 
multifrequency ionospheric equipment at 
several field-stations resulted in numerous 
requests for ionospheric data from federal 
agencies and from our allies. Special ar- 
rangements to insure the prompt handling 
and early distribution of such material to 
authorized agencies were undertaken. The 
data play an important role in estimates 
of world-wide ionospheric distribution, 
knowledge of which is essential in con- 
sideration of radio wave-transmission prob- 
lems. 

Publications and Papers 

The Department was represented at the 
Winter (1941-1942) Convention of the In- 
stitute of Radio Engineers in New York 
City by Wells, who presented a paper on 
"Ionospheric investigations at Huancayo 
Magnetic Observatory (Peru) with appli- 
cation to wave-transmission conditions." 
Following a brief description of the prin- 
ciple and design of the automatic multi- 
frequency ionospheric equipment devel- 
oped by the Department, the results of con- 
tinuous observations at Huancayo were 
discussed in some detail. These results are 
representative of average ionospheric con- 
ditions in equatorial regions. Such regions 
play an important part in long-distance 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



59 



radio communications. Typical variations 
from day to night conditions, as well as 
season-to-season changes, were discussed. 
The effect of such ionospheric changes 
upon selection of communication-frequen- 
cies was also emphasized. Normal record- 
ings and the effect of magnetic disturb- 
ances upon the ionosphere were discussed. 
Methods of development and application 
of transmission-graphs were demonstrated. 
Such graphs make possible the conversion 
of the ionospheric data obtained at verti- 
cal incidence into radio wave-propagation 
information at oblique incidence over var- 
ious distances. The E-layer is capable of 
supporting radio transmission over dis- 
tances approaching 1500 miles, and the nor- 
mal limit of single-hop transmission via 
the F-region is somewhat greater than 2000 
miles. 

Recordings of the frequency-separation 
between doubly refracted wave-compo- 
nents in the F-region at Huancayo were 
analyzed in terms of the intensity of the 
Earth's magnetic field at the level of maxi- 
mum electron-density in the ionosphere. 

A paper entitled "Earth's magnetic field 
and actual heights in ionosphere" was 
presented by Wells at the annual meeting 
of the American Geophysical Union in 
April 1942. A radio wave propagated into 
the ionosphere becomes divided into sepa- 
rate wave-components of different polari- 
zations under the influence of the Earth's 
magnetic field. This is similar to the 
Zeeman effect observed when an elec- 
tromagnetic wave is propagated in an 
ionized medium in the presence of a mag- 
netic field. The separation in frequency 
between the individual wave-components 
provides a measure of the intensity of the 
Earth's magnetic field at the actual height 
in the ionosphere from which the signals 
are being returned. From separate records 
at Huancayo of critical frequencies of both 
ordinary and extraordinary wave-compo- 



nents, mean hourly values of the frequency- 
separation over 4 months were used to 
obtain mean hourly values of magnetic 
field-intensity, H, in the ionosphere at the 
height of maximum electron-density. A 
plot of these values reveals a form of di- 
urnal variation for H. Since H is meas- 
ured at the height of maximum electron- 
density, it must be assumed that the di- 
urnal variation in H, as observed by this 
technique, is a result of the change in ac- 
tual height of the region of maximum elec- 
tron-density of the ionosphere. Assuming 
the Earth to be a uniformly magnetized 
sphere, the variation of H with height 
above the Earth may be calculated. This 
provides means for conversion of values 
of H as observed from the ionospheric 
measurements into terms of actual heights. 
The diurnal curve obtained is similar to 
the diurnal curve of ionospheric heights 
obtained independently by other means. 
The technique outlined is particularly ap- 
plicable at the magnetic equator. With 
specially developed apparatus, probably a 
single observation could be used to obtain 
accurate measurement of the intensity of 
the Earth's magnetic field in the iono- 
sphere. 

Wells addressed the Institute of Radio 
Engineers at Cleveland, July 1, 1942, on 
"Effect of solar activity on the ionosphere 
and radio communication." Severe dis- 
turbances in the ionosphere are produced 
by unusual solar activity and in turn 
directly influence radio communication. 
Solar flares or sunspot-eruptions have 
been definitely identified as the origin 
of short-period radio fade-outs. The ultra- 
violet radiation associated with the solar 
flare immediately produces intense ioni- 
zation in the lower part of the ionosphere, 
which results in complete absorption of 
all normal sky-wave radio transmission. 
Disturbances of this nature seldom last 



6o 



CARNEGIE INSTITUTION OF WASHINGTON 



longer than one hour. The most severe 
radio disturbances, however, coincide with 
intense magnetic storms — storms fre- 
quently associated with active sunspot- 
areas. It is generally believed that streams 
of corpuscles are projected from active 
sunspots, travel to the Earth in one to 
four days, and produce magnetic storms, 
auroral displays, and radio disturbances. 
The severe disturbances can disrupt nor- 
mal radio communications for several days 
and interrupt wired circuits. The effect of 



magnetic disturbances on radio communi- 
cation is more pronounced as the wave- 
path approaches the higher latitudes. Iono- 
spheric recordings, by both the fixed-fre- 
quency and the multifrequency techniques, 
provide fundamental information regard- 
ing the development and effect of such 
disturbances on radio communications. 

Valuable reports, compilations, and sum- 
maries of the data obtained from the 
records made at College were prepared by 
Bramhall and Seaton. 



MAGNETISM AND ATOMIC PHYSICS 



Tuve, Hafstad, Roberts, and Abelson 
of the nuclear-physics group were assigned 
during the entire report-year to war-re- 
search activities. Until August 1941, Hey- 
denburg, Meyer, and L. Schmidt were en- 
gaged full time in improvement of the 
Atomic-Physics Laboratory, but they were 
then assigned for most of the time to war 
work using the one-million-volt generator. 
G. K. Green was in charge of the develop- 
ment of the cyclotron until March 12, 1942, 
when he began active duty as lieutenant in 
the United States Signal Corps. From then 
on he generously devoted his scant spare 
time to assuring continuity of the work 
ably carried on by Cowie (assigned from 
the National Cancer Institute), who with 
Ksanda, P. A. Johnson, Buynitzky, and 
Caherty was engaged on the cyclotron 
throughout the report-year. These men 
had the assistance of F. R. Nichols (to 
September 1941) and McCaw (from Oc- 
tober 13, 1941 to June 3, 1942, when he 
joined the United States Army). The 
assignment of Research Fellows N. M. 
Smith, Jr., and J. A. Van Allen to war 
problems was continuous from July 1, 
1 941. Despite this depletion of personnel, 
good progress was made. 



Atomic-Physics Observatory 

During the last few months in 1941 and 
January and February 1942, Meyer and 
Schmidt spent part time in further con- 
struction work on the Atomic-Physics 
Observatory. The accelerating tube had 
been removed from the generator in 1940 
and an effort was made to boost the volt- 
age on the generator by making certain 
changes in the design of the supporting 
column of the high-voltage cap. These 
changes were found to give no substantial 
improvement in the voltage, however, and 
the limit of the generator without the ac- 
celerating tube remained at 4.5 million 
volts. 

Tests were made in the spring of 1941 on 
various accelerating-tube designs in an 
effort to build a tube that would with- 
stand 4.5 million volts without breakdown. 
Working with an 8-foot test-section, a de- 
sign was found using the original tube 
porcelains which gave an improvement of 
50 per cent over the old tube. In July 1941 
the construction of the many electrode- 
parts was begun by Schmidt with part-time 
help by Meyer. The parts were completed 
in January 1942, and Meyer and Schmidt 
then assembled and aligned the tube in the 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



61 



generator. The ion-source was made ready 
for a test of the tube with an ion-beam. 
At this time the upper power-belt-pulley 
assembly was redesigned to allow the ten- 
sion of the belt to be more easily adjusted. 
No difficulty was found in obtaining an 
ion-beam down the tube, but further work 
will be necessary in the refinement of the 
focusing system of the tube before the 
beam will be usable for precise experi- 
ments. 

Cyclotron 

The main units of the 6o-inch cyclotron 
are (i) the magnet, (2) the main vacuum- 
system, (3) the control-system, (4) the 
power-supplies, and (5) the radio-fre- 
quency circuits. (See Year Book No. 40, 
pp. 89-91, for statement regarding the Cy- 
clotron Laboratory and the development 
of the equipment.) 

Magnet. Measurements made soon after 
assembly of the 200-ton Armco magnet 
showed that the pole-faces were out of 
parallelism by 0.007 inch. With the squeez- 
ing out of the heavy oil-film applied to the 
machined surfaces of contact of the four 
top, bottom, and side members, this lack of 
parallelism is now within the limit set 
of 0.003 mcn - The motor-generator has 
characteristics that allow exciting the coils, 
which were built by the General Electric 
Company for a power-input of 75 kilo- 
watts, to 130 kilowatts. Tests to determine 
whether use of full capacity of the genera- 
tor would overheat the coils showed it 
would be safe to energize them continu- 
ously with an input of at least 115 to 120 
kilowatts. 

Before the vacuum-chamber was in- 
stalled, a careful search was made to find 
out if any serious inhomogeneities existed 
in the pole-pieces. This was done by means 
of a coil of many turns connected to a 



fluxmeter. Within the "ion-working space" 
of 50-inch diameter any inhomogeneities 
found in the magnetic field were so small 
as to make it a question whether they were 
real or the result of experimental error. 
Any large blowhole in a pole-piece would 
produce a hole in the magnetic field which 
would ruin the various focusing charac- 
teristics of the cyclotron and make the at- 
tainment of large beam-currents impos- 
sible. 

A record magnetic test was made to 
measure the magnetic field at the center of 
the vacuum-chamber and at several points 
on a radius up to 68 inches at various 
values of exciting current. With the full 
rated current of the generator, 600 amperes, 
the magnetic field in the center, with the 
vacuum-chamber in place including its 
filler-plates, is 17,400 gauss. The f ringing- 
field curve was investigated for four dif- 
ferent values of exciting current and has 
a shape favorable for withdrawing the ion- 
beam from the dees. Measurements of 
absolute value of the magnetic field were 
made with a flip-coil and fluxmeter stand- 
ardized at the National Bureau of Stand- 
ards. It was possible to make these meas- 
urements with an internal consistency 
better than 1 part in 500 and with an 
absolute accuracy of 1 part or less in 200. 

For tests of the azimuthal symmetry of 
the magnetic field, twin flip-coils were 
constructed in such a way that one coil re- 
mains at the center of the magnet, while 
the other revolves on a constant radius. 
The two coils are mounted on a common 
shaft and will be connected in series op- 
position to the fluxmeter. For proper oper- 
ation of the cyclotron it is necessary that 
the field be quite symmetrical azimuthally, 
this being the main reason for the close 
mechanical tolerances on the magnet and 
vacuum-chamber. Any small lack of sym- 
metry can be compensated at least to a 



62 



CARNEGIE INSTITUTION OF WASHINGTON 



first order by inserting the vacuum-cham- 
ber so that it is off center with respect to 
the magnet-poles. The vacuum-chamber 
position can be checked very precisely with 
respect to the pole-pieces, and the necessary 
position for proper magnetic-field require- 
ments can be and must be reproduced 
accurately. The water-flow for the magnet 
was checked and the controlling switches 
were set so that a flow of 3600 gallons of 
water per hour is required to close them. 

Main vacuum-system. The main vac- 
uum-system, which includes the vacuum- 
chamber, dee-tanks, pumps, and various 
appurtenances, was completed and thor- 
oughly tested and all leaks were elimi- 
nated. The four 8-inch oil-diffusion pumps 
were found to have a pumping speed of 
about 2000 liters per second when ordi- 
nary Cenco Megavac oil was used. The 
baffle-systems for these pumps were de- 
signed and installed, as well as appropriate 
vacuum-valves and manifolds. The final 
test of the brass target-box shows it to be 
free of leaks. 

The various components, including tar- 
get-box, vacuum-chamber, cones, cylinders, 
main manifold, pumps, baffles, and valves, 
after individual tests, were assembled, and, 
although there were almost 200 separate 
rubber-gasket seals, a vacuum of 5 X io~ 6 
mm of mercury was obtained within a 
few hours. 

The system was dismounted following 
this test, and the main vacuum-chamber 
was withdrawn from the magnet for the 
installation of the liners and for inspec- 
tion and cleaning before final assembly. 
The pump-out lead was installed in the 
bottom of the vacuum-chamber, and as- 
sembly of copper-liners, radio-frequency 
connectors, dees, and dee-capacity compen- 
sators is under way. 

Before the deflector-dee was designed, the 
path of an ion in the magnetic field when 



subjected to various electrostatic deflections 
was calculated. By means of the deflector- 
electrode an intense transverse electrostatic 
field is set up across the path of an ion 
emerging from the slot in the deflector-dee. 
This field gives the ion a radial compo- 
nent of velocity which starts the ion in a 
path across the fringing-field and allows 
the ion to enter the target-box, the fixed 
openings of which must be cleared by 
the ion if it is to strike the target. With 
the attainable magnetic field, energies of 
approximately 25 million electron-volts 
(MEV) with deuterons and 50 MEV with 
protons are possible. Solution of the differ- 
ential equations of the ion-path is difficult 
because the inherent empirical data can- 
not be expressed in any simple form. 
These empirical data are the shape of the 
fringing-field of the magnet and the 
strength of the varying electrostatic field 
of the deflector-electrode. A numerical 
integration was set up and Miss Lange cal- 
culated the points of the ion-path for a 
deuteron of 21.6 MEV subject to deflector- 
potentials of 120,000 volts and 150,000 volts. 
The resulting paths show that it will be 
feasible to bring out a 21- or 22-MEV 
deuteron-beam with about 120,000 volts 
applied to the deflector-electrode. The 
shape of the wall of the deflector-dee was 
designed to conform with the curves given 
by the numerical integration. 

Control-system. The control-desk and 
the relay-box on the control-room wall are 
essentially complete. Minor schematic dia- 
grams of the control-system wiring were 
made. 

Power-supplies. The ion-source requires 
two power-supplies, (1) to light the fila- 
ment, and (2) to create the arc from the 
ion-source filament to the ion-source cone. 
The latter emission-supply was completed. 
It consists of a three-phase bridge-rectifier 
in which the power-transformers are pre 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



63 



ceded by a constant-current network of 
chokes and condensers; it delivers an es- 
sentially constant current independent of 
load-impedance. The current is varied by 
switching in condensers. The filament of 
the ion-source will be powered by a small 
motor-generator set mounted on top of the 



magnet. 



The deflector-electrode is supplied by an 
air-insulated voltage -doubler rectifier capa- 
ble of output-potentials from to 200,000 
volts. This complete power-supply was in- 
stalled in a wire-mesh cage to insure pro- 
tection of personnel. The test of this unit 
showed it to be perfect with the exception 
of a coronal breakdown on the 110,000- 
volt Westinghouse transformer. 

Two power-supplies are required for the 
radio-frequency system. The first, which 
is completed, is a single-phase, 3000-volt, 
1. 25 -ampere rectifier to supply the final 
stage of the exciter. The second, which 
is in construction, is a 200-kilowatt, three- 
phase, full-wave bridge -rectifier, utilizing 
six Federal Telegraph mercury-vapor rec- 
tifier-tubes, to furnish power to the plates 
of the final stage of the oscillators. The 
plate-transformer for this rectifier was in- 
stalled in the power-room with a concrete 
curb cast around it with provision for 
draining any large leakage of oil from the 
transformer. A steel rack adjacent to the 
transformer will contain the rectifier-tubes, 
their filament-transformers, various pro- 
tective equipment, and a blower controlled 
by thermostats. 

All the power-supplies are enclosed in 
protective cages equipped with door 
switches which automatically disconnect 
the high voltage when a door is opened. 
Grounding chains will also be installed 
so that the output can be grounded by 
anyone working on the power-supply. 

Radio-frequency system. The radio-fre- 
quency system is designed to have a mas- 
ter-oscillator, controlled by a crystal-driven 



circuit or by stable inductance-capacitor 
circuits, the output of which is to be am- 
plified by several stages of buffer-amplifier 
equipment driving the final radio-fre- 
quency amplifier. The final amplifier of 
the exciter is a large water-cooled tube to 
excite the grids of two water-cooled tubes 
in a push-pull circuit coupled by a trans- 
mission-line to the resonant circuit in the 
main vacuum-system. The filament and 
grid-supporting structures, anodes, and 
water-jackets for these tubes were com- 
pleted. The design of these tubes is along 
lines suggested by Smith and Ayer, of 
Radio Corporation of America. Difficulty 
is being experienced in obtaining satis- 
factory insulators to support the grid- and 
filament-structures. These tubes are de- 
mountable and may be continuously 
pumped, so that they can be repaired 
quickly by installation of spare parts. 

It is to be hoped that the instrument can 
be tuned up initially to produce a 100- 
microampere beam-current of 21 MEV 
deuterons. The radiation produced by such 
a beam is enormous, and will make neces- 
sary the installation of water-tanks and 
frequent radiation-surveys for the protec- 
tion of personnel operating the cyclotron 
and occupying other parts of the labora- 
tory. 

Miscellaneous 

The reduced staff and the work of de- 
sign and construction of the cyclotron 
prohibited any extended nuclear-physics 
research or completion of manuscripts on 
work already done. 

Cowie found time, however, to cooper- 
ate with Drs. Voegtlin, Thomson, and 
Johnson, of the National Cancer Institute, 
in an investigation, still in progress, of 
chemotherapeutic effects of radioactive ar- 
senic on liver tumors. 

Cowie was coauthor with Colonel A. A. 
de Lorimier, of the Army Medical School, 



6 4 



CARNEGIE INSTITUTION OF WASHINGTON 



and Dr. T. N. White, of the National 
Cancer Institute, of two reports to be 
published in the American Journal of 
Roentgenology. The titles are as follows: 
"Radiation hazards during roentgenos- 
copy," by T. N. White, Dean B. Cowie, 
and A. A. de Lorimier; "Protective fea- 
tures provided with the U. S. Army field 
X-ray equipment," by A. A. de Lorimier, 
Dean B. Cowie, and T. N. White. Cowie 
attended a meeting of the National Ad- 
visory Committee on X-Ray and Radium 
Protection at the Army Medical Center, 
Walter Reed Hospital, June 13, 1942, at 
which these subjects were discussed. 

An article on a new type of radiation 
ell for the manipulation of radium was 
prepared by Drs. A. H. Dowdy and B. Du 
Bilier, of the Strong Memorial Hospital of 
the University of Rochester, and Cowie. 
This paper was accepted for publication in 
the American Journal of Roentgenology. 

Theoretical-Physics Conference 

The Eighth Annual Washington Con- 
ference on Theoretical Physics was held 
April 23-25, 1942, in Washington, D. C, 
under the joint auspices of the Carnegie 
Institution of Washington and the George 
Washington University. The subject, "The 
problems of stellar evolution and cosmol- 
ogy," was essentially the further develop- 
ment of discussions at the conference of 
1938 on "Problems of stellar energy- 
sources." There seems hardly any doubt 
that the so-called "carbon cycle," then pro- 
posed by Bethe, actually represents the 
source of energy for our Sun and for all 
other stars of the "main sequence" and 
that the energy-source of the so-called "red 
giant stars" lies in the thermonuclear re- 
actions of lithium, beryllium, and boron, 
as was proposed by Gamow and Teller. 

The problem of stellar evolution, that is, 
of changes with time in the observable 



characteristics of a star, still presents seri- 
ous difficulties, particularly in its applica- 
tion to the "red giants." Study of the so- 
called "shell-model" of a star proposed by 
Gamow in the 1938 conference was con- 
siderably advanced during the last year by 
Chandrasekhar and Schoenberg, who re- 
ported their results at the first session of 
the Eighth Conference. 

On the question of the "mixing-up" 
process in a stellar interior, Randers re- 
ported his calculations of the convection- 
processes in rotating stars. 

The problem of the correlation of vari- 
ous theoretical viewpoints on stellar evo- 
lution and the observational facts on the 
relative abundance of stars of various types 
was discussed. Shapley gave a general sur- 
vey of the observational evidence. To cor- 
relate the theoretical picture of stellar evo- 
lution with the observational material, it 
is necessary to take into account the stellar 
population in various parts of the universe. 

The second problem of the conference 
was that of the expanding universe and the 
related question of the origin of chemical 
elements during the early stages of the 
expansion. There is still considerable dis- 
agreement among investigators as to 
whether our universe is an expanding one. 
Consideration of the several estimates of 
the age of the universe indicated that the 
problem of the expanding universe must 
await more information regarding the evo- 
lutionary history of separate nebulae. 

Thomas reported his attempt to explain 
the red-shifts in the spectra of distant light- 
sources as resulting from the interaction 
of the traveling light-quanta with the free 
electrons in interstellar space. 

The attempts to explain the observed 
relative abundance of various chemical ele- 
ments in the interiors of various stars have 
followed two different directions. It is 
suggested: (1) that the present abundance 
arises from some kind of chemical equi- 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



65 



librium between various nuclei at certain 
high temperatures and densities; (2) that 
the origin of elements is a breaking-up 
process similar to the recently discovered 
process of uranium-fission. Both points 
were discussed and it was agreed that the 
second view is the more probable. Chan- 
drasekhar reported on the "equilibrium- 
theory." Some details of a breaking-up 
process of the heavy fragments of primary 
nuclear matter which would finally lead 
to the ordinary nuclei of the known stable 
elements were discussed by Teller. 

During the third day fundamental prob- 
lems of physical constants and the proper- 
ties of elementary particles were discussed. 
Teller criticized Dirac's recently expressed 
view that the number of elementary par- 
ticles in the universe and also the value 
of the gravitational constant are slowly 
changing with time. Assuming Dirac's 
hypothesis, he would expect large changes 



in the luminosity of the Sun, which is con- 
trary to geological evidence. 

Thomas presented his recent attempt to 
build up a formalism for consistent quan- 
tization of the electromagnetic field which 
would eliminate the difficulties inherent in 
the infinite self-energy of elementary parti- 
cles. 

Pauli discussed the theory of the "meso- 
tron" on the assumption of zero-spin and 
concluded that this assumption is not satis- 
factory. 

Twenty-six investigators from fifteen 
universities and research organizations 
took part in the conference. Several lead- 
ing nuclear physicists and astronomers 
who had also accepted invitations to take 
part could not do so because of urgent 
unexpected demands of war problems. (A 
more detailed account of the conference 
is published in Science, vol. 95, pp. 579- 
581, 1942.) 



FIELD-WORK AND REDUCTIONS 
LAND MAGNETIC SURVEY 



Additional material for the volume in 
the series of Researches of the Department 
of Terrestrial Magnetism on "Land Mag- 
netic Survey, observations, 1927-1940" was 
prepared. The manuscript, by J. W. Green, 
Fleming, Vestine, and Wallis, is now ready 
for the preparation of the master copy for 
publication by the offset method. 

Various governmental and private or- 
ganizations were supplied with tabulations 
of magnetic data, geographical positions 
and descriptions of stations, and local maps 
for Africa, Australia, New Zealand, the 
Pacific islands, Central America, North 
America, South America, and the polar 
regions. Revisions were made of the com- 
putations of results obtained in the field 
by the United States Antarctic Expedition 
of 1940-1941 and the Louise A. Boyd Arc- 
tic Expedition of 1941. 
8 



The Department cooperated, through 
the loan of field-instruments and equip- 
ment to six observatories, to magnetic sur- 
veys in South Australia, Northern Aus- 
tralia, New Zealand, British East Africa, 
and the United States, as well as to the 
Boyd Arctic Expedition. International 
magnetic standards and corrections thereto 
for field-instruments were maintained as 
heretofore in cooperation with the United 
States Coast and Geodetic Survey at the 
Cheltenham Magnetic Observatory, where 
CIW sine-galvanometer 1 and CIW 
Schultze earth-inductor 48 are used as in- 
struments to control these standards. 

Field-Operations and Cooperative 
Surveys 

Africa. Dr. A. Walter, Director of the Brit- 
ish East African Meteorological Service, using 



66 



CARNEGIE INSTITUTION OF WASHINGTON 



CIW magnetometer and inductor 13, con- 
tinued active cooperation with the Depart- 
ment. In addition to the occupation of sta- 
tions reported previously, he secured repeat- 
observations at the Seychelles and at Arusha, 
Tanganyika Territory, in October 1941. Ob- 
servations at Kabete, Nairobi, were discon- 
tinued during February to September but 
were resumed in October 194 1. Dr. Walter 
reports that every effort was made during the 
report-year to obtain monthly observations at 
Kabete to check secular variation. During 
1942 he expected also to reoccupy stations at 
Fort Hall, Nanyuki, Naivasha, Gilgil, Equa- 
tor, and Nakura in Kenya. 

At Hermanus Observatory, where the secu- 
lar variation of the Earth's field is very large, 
Dr. A. Ogg, of the Magnetic Branch of the 
Trigonometrical Survey of the Union of 
South Africa, obtained measurements at fre- 
quent intervals using CIW magnetometer- 
inductor 17. Through Dr. Ogg were received 
also the annual values for the observatory at 
Elisabethville and recent charts of magnetic 
declination with estimates of secular change 
for the Belgian Congo. 

Australia. The personnel of the Aerial, 
Geological and Geophysical Survey of North- 
ern Australia of the Australian Department 
of Mines has been banded together for the 
duration of the war at the Commonwealth's 
Department of Supply and Development at 
Canberra. The survey originally planned 
using CIW magnetometer-inductor 18 was 
completed. According to a report on August 
12, 1942 from Chief Geologist J. M. Rayner, 
the original project for the continuation of 
the isogonic map of Australia, "based almost 
entirely on the observations made by the 
Department of Terrestrial Magnetism," was 
greatly extended during the course of the 
reductions, and isogonic maps going far to 
the north and east of Australia were pre- 
pared. These included isoporic charts for 
recent epochs. 

The latest corrections in standards for CIW 
magnetometer 6 and dip-circle 226, on loan 
for survey-operations to the Adelaide Ob- 
servatory of South Australia, were compiled 
and forwarded to Astronomer G. F. Dodwell, 



who is compiling the results of observations 
made with them by his staff. 

New Zealand. The Department cooperates 
with the New Zealand Magnetic Survey of 
the New Zealand Department of Scientific 
and Industrial Research through the loan of 
CIW magnetometer-inductor 27. Director H. 
F. Baird reports that by March 1942, despite 
the extension of the war, well distributed 
CIW repeat and new stations totaled 55, and 
that 7 more would be completed in March. 
These results are especially needed for the 
investigation of secular changes and the 
preparation of isoporic charts for the past 
decade. 

Dr. E. Marsden, Secretary of the New Zea- 
land Department of Scientific and Industrial 
Research, used a newly developed CIW in- 
strument to make magnetic measurements 
in the Pacific Ocean and New Zealand. 

North, Central, and South America. CIW 
magnetometer-inductors 26 and 28 were 
loaned to the United States Coast and Geo- 
detic Survey for use in the Western Hemi- 
sphere on surveys (1) in the western United 
States and (2) in the Caribbean area and 
Central and South America, through arrange- 
ments made by the United States Department 
of State. 

During the latter trip of 25,000 miles — 
95 per cent by air — 56 stations, most of which 
were reoccupations of CIW stations, were 
occupied, as follows: Balboa and Coco Solo 
in the Canal Zone; Pinar del Rio, Havana, 
Camaguay, and Santiago in Cuba; Kingston 
(Stony Hill), Woods, and Old Harbor in 
Jamaica; Port-au-Prince in Haiti; Puerto Plata 
and Ciudad Trujillo in the Dominican Re- 
public; San Juan (Observatory) in Puerto 
Rico; St. Johns, Umbrella, Rat, and Henzell 
in Antigua; Port-of-Spain, Gordon, Harts 
Cut, and Junction in Trinidad; Georgetown, 
Bartica, and British Guiana 114 in British 
Guiana; Vassouras (Observatory), Rio de 
Janeiro, Bahia, and Belem in Brazil; Monte- 
video in Uruguay; Barcelona, Caracas, Ciu- 
dad Bolivar, Barquisimeto, Valera, and Mara- 
caibo in Venezuela; Barranquilla, Cartagena, 
Medellin, Pleyades, Puerto Colombia, and 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



67 



Bogota in Colombia; San Jose and Uvita 
Island in Costa Rica; Teoloyucan, Ciudad del 
Carmen, and Chetumal in Mexico; Colon, 
Old Panama, and David in Panama; Corinto 
and Managuas in Nicaragua; Puerto Cortez 
and Tegucigalpa in Honduras; La Union and 
San Salvador in El Salvador; Guatemala City 
in Guatemala. Eight magnetic stations were 
subsequently occupied in Bermuda, following 
which the complete standardization of instru- 
mental equipment was completed at the 
Cheltenham Magnetic Observatory. 

Arctic. The Louise A. Boyd Arctic Ex- 
pedition of 1941 (June to November), under 
the leadership of Miss Boyd on Captain 
Bartlett's schooner Effie M. Morrissey, ob- 
tained magnetic data using CIW magne- 
tometer-inductor 16 and dip-circle 222. In- 
structions and compilations of data were 
prepared by the Department, and the ob- 
servers were instructed in methods of obser- 
vation and computation for magnetic and 
astronomical determinations. Control of in- 



strumental constants and corrections on 
standards were effected at the Cheltenham 
Magnetic Observatory. The stations occu- 
pied, italics indicating repeat-stations, were: 
St. John's in Newfoundland; Dundas Harbor 
in North Devon Island; Pond's Inlet, Clyde 
River, Cape Searle, Pangnirtung, and York 
Sound (south side of Frobisher Bay) on Baf- 
fin Island; and Hoped ale and Battle Harbor 
in Labrador. The expedition was under the 
scientific sponsorship of the National Bureau 
of Standards. Ionospheric characteristics as 
determined by special radio measurements, 
auroral conditions, and measurements of ul- 
traviolet-light intensities were also included 
in the program. The magnetic results are 
valuable in a region where data are especially 
needed. 

Miss Boyd supplied values of magnetic dec- 
lination obtained on her East Greenland Ex- 
pedition of 1938 at 4 stations on Jan Mayen 
Island, 1 in Spitzbergen, and 7 in eastern 
Greenland. 



OBSERVATORY-WORK 



Johnston was in charge of the Section 
of Observatory- Work. The reductions of 
magnetic data and computations in con- 
nection with the analysis of the magnetic 
results from the observatories were con- 
tinued with the assistance of Scott and 
Miss Balsam. McNish and Torreson were 
engaged in war investigations throughout 
the report-year. McNish prepared a paper 
on "The aurora and geomagnetic storm of 
September 18-19, I 94 1 -" Wait discussed 
further the atmospheric-electric and mete- 
orological data from Watheroo and Huan- 
cayo for the 11 -year period 1 924-1 934; he 
and Torreson published a paper on these 
investigations. Wait continued to study 
the atmospheric-electric data for Watheroo 
and Huancayo and completed two addi- 
tional papers, one on the effect of smoke 
on the Watheroo data, and the other on 
simultaneous atmospheric-electric observa- 
tions over the oceans and at Watheroo. 



The complete geomagnetic program was 
maintained at Watheroo and Huancayo 
observatories. At Watheroo, in cooperation 
with the Australian Commonwealth De- 
partment of Air, weekly summaries of 
ionospheric data, forecasts of conditions 
likely to affect short-wave radio trans- 
mission, and predicted values of maximum 
usable frequencies for various distances 
were prepared. The geomagnetic program 
at both observatories comprises continu- 
ous records of the three magnetic elements 
(D, H, and Z), positive and negative con- 
ductivity of the air, atmospheric potential- 
gradient at the surface, earth-currents in 
two directions at right angles with dupli- 
cate lines, heights of the ionosphere by 
fixed frequency and automatic multifre- 
quency, daily spectrohelioscopic observa- 
tions during the periods assigned by the 
International Astronomical Union, and the 
meteorological elements. A three-compo- 



68 



CARNEGIE INSTITUTION OF WASHINGTON 



nent seismograph and precision cosmic- 
ray meter are also operated at Huancayo. 

The Section continued the reduction of 
the magnetic data from Watheroo and 
Huancayo observatories. Final reductions 
were made for the year 1940 and pre- 
liminary compilations for the year 1941. 
The final values of the magnetic elements 
for all days during 1940 and the prelimi- 
nary values for 1941 are shown in table 4. 

The extensive program of reporting 
weekly the magnetic three-hour-range in- 



reduced indices Kr. The world-wide K w 
is introduced in order to obtain an average 
of the reduced indices, in which Kr from 
high-latitude stations are given double and 
equatorial stations single weights. Indi- 
vidual indices from each of the seven 
American-operated observatories and the 
weighted mean index (Kw) are mailed out 
weekly by the Section to governmental 
agencies and other interested persons. K- 
indices and other cosmic data were pub- 
lished quarterly. In order to characterize 



TABLE 4 

Annual values of the magnetic elements at the Watheroo and Huancayo magnetic 
observatories as based on magnetograms for all days, iq4o and i94i 



Year 



Decli- 
nation, 
D 



Incli- 
nation, 
7 



Intensity-components 



Hori- 
zontal, 
H 
(7) 



Total, 
F 

(7) 



North- 
south, 

X 

(7) 



East- 
west, 

Y 

(7) 



Vertical, 
Z 
(7) 



Local 

MAG- 
NETIC 

CON- 
STANT, 

G 



Watheroo Magnetic Observatory 


1940 

1941 


3° 15'.8 W 
3 12.2 W 


64° 24:3 S 
64 25.1 S 


24700 
24705 


57175 
57216 


24660 
24666 


-1406 
-1381 


-51564 
-51607 


35704 
35723 


Huancayo Magnetic Observatory 


1940 

1941 


6 55.9 E 
6 50.3 E 


2 14.3 N 
2 13.6 N 


29517 
29471 


29540 
29493 


29302 
29262 


3562 
3509 


1154 
1146 


29524 
29477 



dex K between o and 9 (Year Book No. 
40, p. 99) was continued, in conformity 
with the resolution passed by the Associa- 
tion of Terrestrial Magnetism and Elec- 
tricity of the International Union of Ge- 
odesy and Geophysics at its Seventh As- 
sembly in September 1939. X-indices for 
the 7-day period ending Greenwich mid- 
night on Friday are regularly transmitted 
to the Washington office both by our ob- 
servatories and by the five magnetic ob- 
servatories of the United States Coast and 
Geodetic Survey. The X-indices are as- 
sembled by the Section and standardized 
by means of keys for transforming K into 



each day's succession of eight three-hour 
intervals by a single index with due al- 
lowance for the actual ranges experienced, 
the computation of daily indices B was 
continued and completed for the year 1941. 
Despite disordered world-affairs, corre- 
spondence with foreign observatories in 
regard to ^-indices and character-figures 
(on scale 0, 1, and 2) was maintained. K- 
indices have been supplied by 12 observa- 
tories, namely (in order of geomagnetic 
latitude), Lerwick, Dombas, Meanook, 
Eskdalemuir, Rude Skov, Agincourt, Wit- 
teveen, Abinger, Niemegk, San Fernando, 
Z6-Se, and Cape Town (Hermanus). The 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



6 9 



^-indices for the second halt of 1940 
and first half of 1941 for these 12 mag- 
netic observatories were tabulated. Those 
for the second half of 1940, together 
with summaries for the whole of 1940, 
were published, ^-indices for the year 1940 
for Sodankyla, Slutzk, Chambon-la-Foret, 
Apia, Kuyper, Pilar, and Amberley were 
tabulated and are awaiting publication, as 
are also compilations of daily mean K- 
indices from 25 observatories (7 American- 
operated and 18 world-wide) for January 
to December 1940. 

The Department and the United States 
Coast and Geodetic Survey, in cooperation 
with the communication-services of the 
United States Army and the United States 
Navy and several amateur radio stations, 
continued to supply the American half-day 
and whole-day magnetic character-figures 
(d) based upon the reports of the seven 
American-operated observatories. Whole- 
day magnetic character-figures (C) were 
assembled for those world-wide magnetic 
observatories reporting them. 

Cooperation in the magnetic and atmos- 
pheric-electric programs of the Department 
was given by various magnetic observa- 
tories. Our international magnetic stand- 
ards were maintained at Cheltenham Mag- 
netic Observatory, and the continuous re- 
cordings of atmospheric conductivity (posi- 
tive and negative) and potential-gradient 
and of earth-currents were continued at 
the Tucson Magnetic Observatory; both of 
these observatories are operated by the 
United States Coast and Geodetic Survey. 

The Section continued the reduction of 
the geomagnetic data from the Watheroo 
and Huancayo observatories. Final reduc- 
tions were made for the year 1940 and 
preliminary compilations for the year 1941. 

Compilations to make current the an- 
nual values of all the geomagnetic elements 
(D, H, Z, I, X, Y, and F) for the world's 



magnetic observatories were begun by En- 
nis and completed by Scott after the for- 
mer's death. 

Operations at Observatories 

Watheroo Magnetic Observatory, Wathe- 
roo, Western Australia. The Watheroo Mag- 
netic Observatory is situated in latitude 30 
19^1 south and longitude 115 52'6 east of 
Greenwich, 244 meters (800 feet) above sea- 
level. 

The Eschenhagen magnetograph was in 
continuous operation. Weekly determina- 
tions of the values of the base-lines for the 
three elements were made in the absolute 
observatory. Control of the scale-value of 
the horizontal-intensity variometer was main- 
tained by monthly determinations, using the 
method of magnetic deflections. Scale-values 
of the vertical-intensity variometer were de- 
termined daily by the electrical method. 

The la Cour rapid-running magnetograph 
was in operation throughout the year. Deter- 
minations of scale-value were made at 
monthly intervals, using the electrical meth- 
od. The monthly scale-values for both the 
Eschenhagen and la Cour magnetographs are 
shown in table 5. 

The preliminary values for the annual 
changes in the magnetic elements during 
1940.5 to 1941.5 are: declination, +^.6; hori- 
zontal intensity, +5 gammas; vertical inten- 
sity, — 43 gammas; inclination, — of8 (see 
table 4). 

Numerous requests have been received for 
magnetic data, principally the values of dec- 
lination at various points in the state of 
Western Australia, from the different 
branches of the defense services, and in order 
to supply this information in a suitable form, 
an isogonic map of Western Australia was 
prepared showing lines of equal magnetic 
declination for the year 1942; copies of this 
map have been furnished to the military 
authorities and to the Department of Lands 
and Surveys. 

As in previous years, three -hour-range in- 
dices, K, were assigned from an examination 



70 



CARNEGIE INSTITUTION OF WASHINGTON 



of the Eschenhagen traces and transmitted 
weekly to Washington through the Australian 
Commonwealth Department of Air. 

There were 12 major magnetic disturbances 
during 194 1; table 6 shows details of these 
storms, full descriptions of which were for- 
warded to Washington monthly. 

The recording of earth-currents was con- 
tinued; the system of electrodes and methods 
of registration will be found described in 
previous reports. The scalings and prepara- 

TABLE 5 

Scale-values of magnetographs, Watheroo 
Magnetic Observatory, 1941 



Month 



January. 
February 
March . . 
April.. 
May. . 
June. . 
July.. 
August 
September 
October. . 
November 
December. 



Scale-values in 7 /mm 



Eschenhagen 



H 
(reduced 
to base- 
line) 



2.38 
2.39 
2.38 
2.39 
2.40 
2.39 
2.39 
2.40 
2.40 
2.43 
2.40 
2.40 



z 

(means 
of daily 
values) 



3.34 
3.35 
3.36 
3.33 
3.35 
3.21 
3.23 
3.27 
3.29 
3.30 
3.34 
3.25 



LA COUR 



II 



61 

51 
44 
47 
47 
42 



4.44 
4.59 
4.42 
4.56 
4.51 
4.48 



2.98 
2.70 
2.82 
2.97 
3.26 
3.20 
3.26 
3.57 
3.51 
3.24 
3.06 
3.06 



made on days when meteorological conditions 
were favorable. 

Positive and negative air-conductivities 
were also recorded continuously. From the 
tabulated hourly values of both potential- 
gradient and conductivity, certain days had 
to be excluded owing to adverse weather con- 
ditions or the smoke from bush-fires. Pre- 
liminary mean values of the atmospheric- 
electric elements are shown in table 7. 

The automatic multifrequency ionospheric 
recording apparatus has functioned practically 

TABLE 6 

Details of magnetic disturbances recorded at 

the Watheroo Magnetic Observatory 

during 1 94 1 



• 

Date 


Ranges 


H 
W 


D 

(') 


z 

(7) 


January 3-4 

January 24 

March 1-2 

March 13-14 

March 28-31 

April 24-25 

July 4-7* 

August 4-5 

September 18-19* 
October 3 1-November 1 

November 27-28 

December 1-2 


85 
107 
658 
149 
185 
148 
563 
168 
684 
173 
148 
147 


14 

24 
77 
21 
32 
22 
65 
26 
73 
19 
18 
29 


59 
135 

>350 
162 

>194 
144 

>215 
195 

>336 
149 
129 
202 



* Aurora australis observed. 



tion of monthly curves of diurnal variation 
were kept current; by this means electrode- 
faults or anomalies can be quickly detected. 
The earth-current recorder, being visual, has 
proved valuable in the early detection of the 
commencement of magnetic disturbances and 
gives a warning of disturbed conditions in 
the ionosphere. 

Air-potentials were continuously recorded 
as in previous years. The reduction of the re- 
corded values to the potential which would 
be recorded at a point 1 meter above a plane 
surface was controlled by series of eye-obser- 
vations, using the stretched-wire method, 



continuously throughout the year, the only 
interruptions being due to necessary mainte- 
nance, control -observations, adjustments, and 
minor repairs. The antenna-systems were 
serviced as required. Scalings and reductions 
have been maintained strictly current. Tables 
8 and 9 show the mean hourly values of 
ionospheric data for 194 1. The Australian 
Commonwealth Department of Air was sup- 
plied with weekly coded reports of iono- 
spheric conditions and also, when necessary, 
warning of approaching conditions likely to 
affect high-frequency radio transmission. Pre- 
dicted values of maximum usable frequency 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



71 



over various distances of path were regularly 
supplied to the Department of Air. Iono- 
spheric data were communicated to the Radio 
Research Board of the Commonwealth Coun- 
cil for Scientific and Industrial Research, the 
Chief Radio Inspector of the Postmaster- 
General's Department, and the (United 
States) National Bureau of Standards. 

A regular watch was kept, using the Hale 
spectrohelioscope, for solar activity, and re- 



Scalings and reductions were maintained 
practically current until the end of 1941, 
when, owing to the great reduction in the 
staff, some of the scalings had to be post- 
poned. Essential control-observations and re- 
ductions, however, were kept current. 

W. C. Parkinson continued as Observer- 
in-Charge. McCarthy left on July 15, 194 1, to 
go with the Radio Research Board; he was 
replaced by Norman (beginning July 1, 



TABLE 7 

Preliminary monthly mean values of atmospheric-electric elements, 
Watheroo Magnetic Observatory, 1941 



Month 



Potential-gradient 



No. 

se- 
lected 
days 



Reduction- 
factor 



Value 
(v/m) 



Air-conductivity, unit 10~ 4 ESU 



No. 
se- 
lected 
days 



X + 



(X++X-) 



(X+/X-) 



January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November 

December 

Totals and means 



19 
19 
24 
18 
20 
14 
15 
21 
21 
25 
20 
12 



228 



18 



05 



1.12 



92.8 

95.7 

94.9 

66.8 

57.4 

65.0 

63. 

71. 

76. 

70. 

84.0 

79.1 



17 
19 
23 
16 
19 
10 
11 
26 
26 
26 
22 
24 



1.84 
1.42 
1.38 



86 
49 
52 
43 
25 
1.94 
1.75 
1.55 
1.63 



1.72 
1.31 
1.25 
1.69 
2.33 
2.26 
2.11 
1.87 
1.57 
1.70 
1.40 
1.58 



77.3 



239 



1.92 



1.73 



3.56 
2.73 
2.63 
3.55 
4.82 
4.78 
4.54 
4.12 
3.51 
3.45 
2.95 
3.21 



3.65 



1.07 
1.08 
1.10 
1.10 
1.07 
1.12 
1.15 
1.20 
1.24 
1.03 
1.11 
1.03 



1.11 



ports of the observations were transmitted 
monthly to Washington. 

Observations of meteorological phenomena 
were made regularly as in previous years. 
Monthly summaries were supplied, as be- 
fore, to the Commonwealth Weather Bureau, 
and, in addition, on and after January 9, 1942, 
telegraphic coded weather-reports were pre- 
pared and transmitted at 09 11 , 12 11 , and 
i8 h daily (120 east meridian time) to the 
Divisional Forecasting Offices of the Depart- 
ment of Air at Perth and Geraldton. Table 
10 shows rainfall at Watheroo during 1941. 



1941). Muhling resigned on August 31, 1941, 
to enlist in the Australian Navy; Lucas left on 
January 29, 1942, to take up work at the 
University of Western Australia. On January 
1, 1942, W. D. Parkinson was appointed as 
temporary part-time observer, the remainder 
of his time being occupied with work at the 
Observatory for the Department of Air. A 
mechanic and assistant mechanic are regu- 
larly employed. The general hand who left 
in January 1942 could not be replaced be- 
cause it was impossible to obtain an able- 
bodied man for the work. 



TABLE 8 



Preliminary mean hourly values of ionospheric data, 
Watheroo Magnetic Observatory, 1941 



120° 

east meridian 

time 

(h) 



00 

01 

02 

03 

04 

05 

06 

07 

08 

09 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22. 

23. 



(km) 



244 
230 
225 
223 
218 
217 
221 
227 
230 
232 
240 



n Fl 
(km) 



233 

225 
217 
215 
210 
211 
214 
219 
222 
226 
231 



7 max 
' l Fi 

(km) 



335 
332 
327 
322 
319 
315 
298 
280 
284 
298 
305 
309 
309 
314 
308 
303 
294 
289 
287 
300 
313 
328 
339 
342 



nun 
Fi 



h 

(km) 



260 
256 
251 
249 
250 
252 
247 
256 
274 
293 
296 
298 
300 
298 
292 
284 
271 
254 
234 
230 
237 
250 
259 
262 



f°E 

(Mc/sec) 



.70 
.11 
.67 
00 
21 
30 
34 
31 
25 



3.08 
2.80 

2.28 
1.74 



(Mc/sec) 



3.90 
4.04 
4.30 
4.54 
4.63 
4.69 
4.67 
4.56 
4.36 
4.11 
3.97 



f°F, 
(Mc/sec) 



36 
24 
06 
90 
70 
54 



3.89 
5.11 
6.07 
6.65 
7.20 
7.57 
7.82 
7.92 
8.02 
7.91 
7.57 
7.17 
6.44 
5.56 
5.03 
4.65 
4.51 
4.44 



J min 

(Mc/sec) 



0.60 
0.68 
0.79 
0.83 
0.90 
0.92 
0.95 
0.94 
0.91 
0.88 
0.79 
0.73 
0.65 



TABLE 9 

Preliminary monthly means of hourly values of ionospheric data, 
Watheroo Magnetic Observatory, 1941 



Month 


j max 

h Fl 

(km) 


fl Fl 

(km) 


7, max 
rip., 

(km) 


jmin 
(km) 


f°F 
(Mc/sec) 


(Mc/sec) 


(Mc/sec) 


J min 
(Mc/sec) 


January 

February 

March 

April 


233 
233 
230 
227 
225 
224 
230 
224 
223 
229 
239 
231 


226 
226 
219 
220 
216 
215 
219 
218 
226 
220 
230 
225 


343 
336 
316 
295 
283 
280 
285 
294 
305 
319 
332 
338 


300 
289 

266 
250 
239 
236 
244 
248 
256 
267 
287 
298 


2.83 
2.95 
2.75 
2.57 
2.56 
2.55 
2.63 
2.69 
2.76 
2.88 
2.87 
2.97 


4.44 
4.29 
4.33 
4.28 
3.98 
3.85 
3.98 
4.30 
4.42 
4.39 
4.36 
4.44 


6.19 
5.65 
6.07 
5.84 
5.16 
5.00 
4.78 
5.16 
5.75 
6.25 
6.30 
6.49 


0.76 
0.77 
0.75 
0.73 


May 


0.70 


June 


0.72 


July 


0.83 


August 

September. . . . 

October 

November. . . . 
December .... 


0.87 
0.99 
0.87 
0.94 
0.84 


Means 


229 


222 


310 


265 


2.75 


4.26 


5.72 


0.81 



72 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



73 



Acknowledgment is gratefully made to var- 
ious government departments for assistance, 
especially valuable under present conditions; 
particularly to the Department of Trade and 
Customs for their continued favorable action 
with regard to equipment and supplies en- 
tering the country, and also to the Wireless 
Branch of the Postmaster General's Depart- 
ment. The Signals Branch of the Department 
of Air has also been most helpful in trans- 
mitting magnetic messages weekly. 

TABLE 10 

Rainfall at Watheroo Magnetic 
Observatory during 1941 



Month 


Monthly 
total 
(in.) 


No. days 


Average 

for 24 years 

(in.) 


January 

February 

March 

April 

May 

June 

July 

August 

September. . . . 

October 

November. . . . 
December. . . . 


0.00 
0.88 
0.05 
1.83 
2.36 
3.76 
1.89 
1.43 
1.65 
0.78 
0.66 
0.13 



2 
3 
12 
8 

16 

17 

11 

13 

6 

6 

3 


0.34 
0.56 
1.04 
0.92 
2.17 
3.39 
2.95 
2.21 
1.27 
0.85 
0.33 
0.37 


Totals 


15.42 


97 


16.40 



To the present reduced Observatory staff, 
who have labored under considerable disad- 
vantages during the past report-year, great 
credit is due for the comparatively satisfactory 
condition of the work on June 30, 1942. 

Huancayo Magnetic Observatory. The 
Huancayo Magnetic Observatory is situated 
about 8V2 miles about west of the town of 
Huancayo in the central valley of the Peru- 
vian Cordillera. It is in latitude 12 02^7 
south and longitude 75 ° 2o'4 west and at an 
altitude of 3350 meters (11,000 feet) above 
sea-level. 

Practically all the Observatory's work is 
done by the use of automatically recording 
apparatus, most of which record photographi- 



cally. Time-control marks on the records arc 
made electrically by lights or mechanical de- 
vices operated by a master clock and program- 
machine which are frequently checked and 
adjusted through the use of radio time-signals. 
Except for the ionospheric recorder and the 
meteorological recorders, all instruments re- 
cord intervals of Greenwich days, since traces 
are changed daily at 19 11 , 75 ° west meridian 
time. Daily development of all photographic 
traces permits excellent control of instru- 
mental equipment. 

The magnetographs consist of two separate 
three-variometer units: an Eschenhagen and 
a rapid-run la Cour, both of which operated 
continuously during the year. A low-sensi- 
tivity la Cour //-variometer also recorded on 
the Eschenhagen magnetogram. Weekly ab- 
solute observations were made with magne- 
tometer and earth-inductor for the control of 
base-lines. Scale-value determinations for the 
H- and Z-variometers of the la Cour magneto- 
graph were made on or near the 15th of 
each month by the Helmholtz-coil method. 
Helmholtz-coil scale-value determinations 
were also made for the Eschenhagen magneto- 
graph, once each week for the H- and D- 
variometers and three times a week for the 
Z-variometer. 

Air-potentials were recorded continuously 
with the standard potential-gradient appara- 
tus. Scale-values were determined once every 
two weeks and reduction-factors quarterly by 
comparisons with potentials measured on the 
standardization-plot near by. Positive and 
negative conductivities of the air were re- 
corded continuously and scale-value deter- 
minations made every two weeks. 

Earth-current potentials were recorded con- 
tinuously on the Leeds and Northrup record- 
ing potentiometer for two separate systems of 
north-south and east-west pairs of electrodes. 

The multifrequency ionospheric equipment 
operated with only minor breaks in continuity 
for maintenance and repair, except during a 
period in the latter part of February and the 
early days of March when two or more days 
of record were lost on three occasions because 
of instrumental difficulties. The fixed-fre- 



74 



CARNEGIE INSTITUTION OF WASHINGTON 



quency equipment recorded regularly until 
the time of the difficulty in February, but was 
disconnected at that time and was only 
returned to operation in the latter part of 
June. Daily control-observations and checks 
were kept up consistently through the year 
and monthly calibrations were made. Com- 
pilations of the scaled values from the traces 
were completed within a few days of the 
month's end and the tabulations forwarded to 
Washington by air. 

The program of daily morning meteoro- 
logical observations was continued as in previ- 
ous years, with recording instruments operat- 
ing continuously in the meteorological shelter 
and in the atmospheric-electric and cosmic- 
ray buildings. Daily determinations were 
made of condensation-nuclei at a point near 
the meteorological shelter each morning at 
the time of the meteorological readings. The 
minimum temperature during the year was 
— 4?3 C and the maximum was 24^6 C; the 
lowest monthly mean minimum was 0^43 C 
in July 194 1 and the highest monthly mean 
maximum was 21^93 in November of the 
same year. The rainfall from July 1, 1941 to 
June 30, 1942 totaled 32.36 inches, well 
above the average for previous years. As be- 
fore, tabulations of meteorological data were 
supplied monthly to the Instituto Nacional 
de Meteorologia e Hidrologia (formerly Ser- 
vicio Meteorologico Nacional del Peru), to 
the Centro Geografica Departamental de Ju- 
nin, and on several occasions to other govern- 
mental agencies and to private persons in- 
terested in the climate of the Sierra. 

Cosmic-ray meter model C no. 2 recorded 
continuously with only minor losses of trace. 
The weekly checks of high-potential balance 
and of the electrometer zeros were continued. 

During the month of June 1941, Ledig 
was able to be of assistance to the cosmic-ray 
expedition of Dr. Arthur H. Compton and 
his associates Drs. Wollan, Hughes, and 
Hilberry. Help was given them in connection 
with the diplomatic procedure of obtaining 
free entry for their scientific equipment of 95 
cases. The personnel were acclimated to the 
high altitude of the Andes by visits at the 



Observatory before leaving for Mahr Tunnel 
and San Cristobal mine (in Peru), where 
Wilson cloud-chamber observations were 
made at an altitude of over 15,000 feet. On 
June 25, Ledig went by plane to Arequipa 
and thence to Mollendo by automobile with 
Dr. Hilberry. He assisted until June 30 
(when he returned by plane to Huancayo) 
in passing the equipment through the cus- 
toms and in unpacking and assembling it, 
preparatory to Dr. Hilberry's ascent of El 
Misti (19,000 feet). Ledig's son Paul ac- 
companied Dr. Hilberry as interpreter and 
general assistant on the ascent of El Misti, 
where records were obtained with a Wilson 
cloud-chamber. 

Two Wenner horizontal-component seis- 
mometers and a Benioff vertical-component 
seismometer recorded satisfactorily through 
the year. Analyses were made of all im- 
portant seismic disturbances and forwarded 
with the monthly journals, and 23 of these 
were sufficiently important to be sent in the 
international seismic code with the weekly 
broadcast of magnetic data. 

Daily observations of the Sun with the 
Hale spectrohelioscope were made as weather- 
conditions permitted, at the assigned observa- 
tional periods. Though only six times during 
the year were there seen activities on the 
Sun that merited careful description, monthly 
reports were prepared and transmitted to 
Washington. 

Although the weekly broadcast of scientific 
data was ordered discontinued in January 
1942 by the Departamento General de Radio- 
telegrafia del Peru, consideration of the Ob- 
servatory's case permitted a reinauguration 
of this service in March. 

The preliminary values for the annual 
changes in the magnetic elements during 
1940.5 and 1941.5 are: declination, —5^6; 
horizontal intensity, —46 gammas; vertical 
intensity, —8 gammas; inclination, —0^7 
(see table 4). 

Preliminary monthly mean values of the 
atmospheric-electric results for the year 194 1 
are given in table n, and the mean hourly 
values of ionospheric data and their monthly 
means for 1941 are listed in tables 12 and 13. 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



75 



As always, the Observatory has enjoyed the 
confidence and friendship of the local Peru- 
vian population, and there has been evidence 
of an increased interest among all Peruvians 
in learning something of the work. There 
were occasional visitors from the American 
colony in Peru as well as British and Ameri- 
can travelers in the country. Assistance by 
the United States Embassy to Peru in ob- 
taining free entry for equipment and sup- 
plies is gratefully acknowledged, and sincere 



tion of all members of the staff made possible 
the successful continuance of the extended 
geophysical program. 

College Observatory, Alaska. In pursuance 
of a comprehensive geophysical program, the 
Department maintained in cooperation with 
the University of Alaska at College, Alaska, 
a complete magnetic, auroral, and ionospheric 
observatory. This Observatory is in the zone 
of maximum auroral activity, about 5 miles 
west of Fairbanks, in latitude 64 ° 51^4 north, 



TABLE 11 

Preliminary monthly mean values of atmospheric-electric elements, 
Huancayo Magnetic Observatory, 1941 



Month 



No. 

SELECTED 
DAYS 



Potential-gradient 



Reduction- 
factor 



Value 
(v/m) 



Air-conductivity, unit 10~ 4 ESU 



X+ 



(A++X-) 



(X+A-) 



January 

February 

March 

April 

May 

June 

July 

August 

September. : 

October 

November 

December 

Totals and means . 



3 

3 

3 

5 

8 

9 

16 

12 

10 

6 

5 

3 



83 



1.17 



1.14 



1.16 



65.1 
87.2 
53.1 
39.9 
48.3 
48.0 
52.2 
48.8 
49.6 
41.9 
47.6 
54.0 



3.30 
2.63 
3.43 
4.19 



91 
60 

89 
38 
05 
65 



4.34 
3.19 



3.01 

2.20 
3.57 
4.77 
4.29 
79 
45 
81 
04 
87 
89 
28 



53.0 



4.08 



6.31 
4.83 
7.00 
8.96 
8.20 
9.39 
8.34 
9.19 
8.09 
9.52 
9.23 
6.47 



7.96 



1.10 
1.20 
0.96 
0.88 
0.91 
0.96 
0.87 
0.91 
1.00 
0.94 
0.89 
0.97 



0.97 



appreciation is expressed for the support and 
cooperation of persons in positions of au- 
thority in the Peruvian government. 

P. G. Ledig as Observer-in-Charge and 
M. W. Jones as observer were members of 
the scientific staff throughout the year. R. C. 
Coile resigned February 9, 1942 to join the 
American Army. He was replaced by A. A. 
Giesecke, Jr., on January 29. E. J. Chernosky 
arrived early in May to become the fourth 
member of the scientific staff. The clerical 
assistants, T. Astete, A. Macha, and V. Murga, 
continued to give excellent service in the 
reduction of data and general operation of 
the Observatory. The enthusiastic coopera- 



longitude 147 49^3 west, at an altitude of 
about 1250 feet (381 meters). 

The insensitive la Cour magnetograph with 
accessory instruments for base-line and scale- 
value determinations was mounted on con- 
crete piers housed in buildings occupied by 
the Second International Polar Year Expedi- 
tion (October 1932 to March 1933) at the 
same location. 

The magnetograph was in continuous oper- 
ation from August 1, 1941. The scale-values 
of the variometers were i8.2y per millimeter 
for horizontal intensity, 27.4-}/ per millimeter 
for vertical intensity, and 5^18 per millimeter 
for declination. Preliminary mean values of 



TABLE 12 



Preliminary mean hourly values oe ionospheric data, 
Huancayo Magnetic Observatory, 1941 



75° 

west meridian 

time 

(h) 



7 max 

h Fl 

(km) 



7, m ' » 

h Fl 

(km) 



j, max 

n F2 

(km) 



np 2 
(km) 



f°E 

(Mc/sec) 



(Mc/sec) 



fk 
(Mc/sec) 



J min 
(Mc/sec) 



00 
01 
02 
03 
04 
05 
06 
07 
08 
09 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 



261 
250 
237 
227 
221 
219 
218 
223 
236 
260 



245 
231 
225 
220 
217 
214 
213 
213 
216 
226 



318 
313 
312 
310 
311 
316 
317 
322 
368 
419 
448 
454 
457 
457 
452 
444 
442 
429 
420 
441 
422 
385 
357 
333 



260 
260 
263 
268 
273 
278 
269 
262 
304 
328 
352 
369 
374 
373 
362 
343 
316 
262 
281 
314 
316 
295 
279 
266 



0.78 
1.59 
2.44 
2.92 
3.36 
3.63 



80 

85 
77 
60 
25 
80 



2.28 
1.30 
0.84 



35 
67 
81 
88 
90 
90 
86 
81 
71 
54 



79 
08 
36 
70 
13 
74 
13 



7.65 
8.99 
9.40 
9.23 
8.93 
8.78 
8.86 
9.10 
9.33 
9.47 
9.49 
9.34 
8.75 
8.28 
8.06 
7.73 
7.26 



0.64 
0.72 
0.87 
1.08 
1.30 
1.46 
1.62 
1.66 
1.61 
1.51 
1.29 
1.12 
0.90 
0.73 
0.66 



TABLE 13 

Preliminary monthly means of hourly values of ionospheric data, 
Huancayo Magnetic Observatory, 1941 



Month 


h Fl 

(km) 


; min 

h Fl 

(km) 


jniax 
flp 2 

(km) 


r min 

(km) 


f°E 

(Mc/sec) 


(Mc/sec) 


Jf 2 
(Mc/sec) 


J min 
(Mc/sec) 


January 

February 

March 

April 


237 
228 
241 
248 
250 
226 
227 
229 
233 
236 
235 
233 


218 

220 
228 
233 
233 
216 
214 
217 
220 
222 
222 
219 


401 
387 
388 
384 
380 
356 
365 
378 
389 
388 
401 
405 


315 
292 
294 
293 
305 
292 
307 
297 
303 
302 
314 
320 


2.90 
2.89 
2.80 
2.63 
2.44 
2.39 
2.49 
2.60 
2.67 
2.74 
2.75 
2.81 


5.02 
4.89 
4.81 
4.74 
4.62 
4.59 
4.63 
4.77 
4.73 
4.66 
4.72 
4.75 


8.00 
8.77 
8.51 
7.94 
6.65 
6.14 
6.11 
7.08 
7.81 
8.49 
8.52 
8.26 


1.28 
1.20 
1.26 
1.08 


May 


1.00 


June 


0.97 


July 


1.07 


August 

September. . . . 

October 

November. . . . 
December. . . . 


1.05 

1.28 
1.29 
1.19 
1.06 


Means 


235 


222 


385 


303 


2.68 


4.74 


7.69 


1.14 



76 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



77 



the magnetic elements, considering all days 
from July 26, 1941 to June 30, 1942, are: 
declination, 29 52^9 east; horizontal inten- 
sity, 12576-y; vertical intensity, 553477; in- 
clination, 77 n'9 north. The resulting pre- 
liminary rates for the annual changes, utiliz- 
ing average values of the magnetic elements 
for epoch 1933.5 as supplied by the United 
States Coast and Geodetic Survey, are: dec- 
lination, 3'8 west; horizontal intensity, oy; 
vertical intensity, — 22y; inclination, —0^3. 

The ionospheric installation — similar to 
that at the Watheroo and Huancayo observa- 
tories — was completed in June 1941- Field- 
intensity recorders were installed early in 
July. Since then complete exploration of the 
ionosphere through automatic continuous 
photographic recording has been made. The 
data comprise direct measurements, or deduc- 
tions from such measurements, of a group 
of sixteen quantities descriptive of the time- 
space distribution of ionospheric ionization 
vertically above the station. The considerable 
quantity of homogeneous data resulting from 
the year's operation will require several years 
for complete analysis, but several important 
contributions have already been made on the 
basis of preliminary work. The theoretical 
postulations of Appleton and Builder (Proc. 
Phys. Soc, vol. 45, pp. 208-220, 1933) con- 
cerning longitudinal type propagation of elec- 
tromagnetic waves through the ionosphere 
in the presence of the Earth's magnetic field 
were confirmed empirically. Ionospheric 
trends and variations obtained at College 
were found to be in reasonably good agree- 
ment with those expected from extrapolation 
of observations at stations in the temperate 
zones. Comparison of theoretical with ex- 
perimental values of maximum usable fre- 
quency added evidence in support of New- 
bern Smith's method (Proc. Inst. Radio Eng., 
vol. 27, pp. 332-347, 1939) of deduction, 
when corrected for ionospheric curvature. A 
technique was developed for applying these 
methods to large quantities of data in order 
that mean values may be converted directly. 

Other geophysical investigations at College 
included both visual and photographic auroral 
observations during hours of darkness from 



October 1941 through April 1942. Estimates 
of auroral indices based on brilliance, ac- 
tivity, and extent of the displays, as well as 
details regarding their form and location, 
were obtained from visual observations at 
half-hour intervals. The photographic pro- 
gram was confined for the most part to pho- 
tographs of the region around the zenith 
obtained at 2.5-minute intervals on 16-mm 
film by an automatic camera developed at 
the Department, and built around a Paillard- 
Bolex moving-picture camera. Preliminary 
analysis of the visual records indicates a pro- 
nounced daily variation in auroral activity 
with a maximum centering around 02 h oo m 
local time. Studies of the occurrence of au- 
roras with concomitant magnetic and iono- 
spheric phenomena show that both magnetic 
activity and abnormal sporadic E-region ioni- 
zation are closely correlated with auroral 
activity. The correlation was particularly evi- 
dent when auroras in the zenith alone were 
considered. 

Berkner was in charge of the Observatory 
through July 194 1, when he transferred the 
Observatory to Bramhall as Physicist-in- 
Charge and returned to Washington to enter 
active duty in the Navy as Lieutenant-Com- 
mander, September 1, 1941. The other mem- 
bers of the staff were Chief Assistant Seaton, 
Observer E. Wolff, Assistant Observers Ohl- 
sen (to September 19, 1941, and from Janu- 
ary 15, 1942), St. Amand (to May 16, 1942), 
and Caulk (to September 15, 1941), and 
Guards Atkinson and Heinrich for part time. 
The successful prosecution of the extensive 
program and the prompt compilations of 
data and reports reflect the competence and 
energy of the staff. 

Cooperation with Other Observatories 

Cheltenham Magnetic Observatory, United 
States. The cooperative program with the 
Cheltenham Magnetic Observatory of the 
United States Coast and Geodetic Survey was 
continued. CIW instruments on loan to the 
Observatory were used to control standards 
in the horizontal and vertical components 
of geomagnetic intensity. Continuous cosmic- 



78 



CARNEGIE INSTITUTION OF WASHINGTON 



ray records were made with the CIW model 
C precision meter. Necessary observations 
for standardization and control of constants 
for CIW instruments before and after assign- 
ments to the field were made. The interest 
and help of the Washington staff of the Di- 
vision of Geomagnetism and Seismology of 
the Survey and of Observer-in-Charge A. K. 
Ludy and assistants at the Observatory made 
for marked efficiency in the cooperative work. 

Apia Observatory, Western Samoa. The 
Department continued cooperation with the 
Apia Observatory, through its Acting Direc- 
tor, H. B. Sapsford, and staff, in geomagnetic 
and atmospheric-electric programs. This Ob- 
servatory also undertakes observations in 
other fields of geophysics, including meteor- 
ology and seismology. 

CIW magnetometer 9 and CIW Schulze 
earth-inductor 2 were used for absolute ob- 
servations of declination, horizontal intensity, 
and inclination. Eschenhagen variometers 
and a Godhavn balance were used to obtain 
continuous photographic records of declina- 
tion, horizontal intensity, and vertical inten- 
sity. The scale-value of the Godhavn balance 
proved satisfactorily constant during the re- 
port-year. The scale-value as determined 
with a Helmholtz coil was 1.31-/ per milli- 
meter and by the oscillation method outlined 
by la Cour 1.337 P er millimeter. 

i^-indices were determined for the year 
1940. X-indices were scaled for the month of 
January 1938, using 300 gammas (0.003 CGS 
unit) for the lower limit of the range for a 
K-index of 9. The frequency-distribution of 
the various /^-indices when compared with 
that at Cheltenham and Honolulu was satis- 
factory. Seasonal variation curves in S q for 
international quiet days during the summer 
and winter solstices and the equinoxes were 
prepared for sunspot-maximum. The amount 
of the diurnal variation due to lunar effect 
was determined, and its range was of the 
order of 3 to 6 gammas. 

Atmospheric potential-gradient was meas- 
ured with a Benndorf electrometer. The 
leak-free potentiometric method of Gish and 
Sherman was used to determine the reduc- 
tion-factor of the Land Station, and results 



showed that its value was still 1.00. During 
194 1, 146 days of zero-character were re- 
corded, with a mean value of 127 volts per 
meter. The monthly number of zero-days and 
average potential-gradients are shown in. table 
14. The annual average hourly values in volts 
per meter based on the monthly means are 
as follows: 95, 95, 94, 98, 100, 109, 151, 
223, 229, 169, 133, 120, no, 103, 102, 101, 
101, 101, 120, 167, 170, 136, 112, and 100. 

The Land Station was closed on December 
31, 1 94 1, and the series of atmospheric poten- 
tial-gradient measurements conducted in co- 
operation with the Department since 192 1 
was thus brought to an end. At the close of 
the first World War the New Zealand gov- 
ernment assumed the operation of the Ob- 
servatory but was unable to provide for the 
expense of the atmospheric-electric observa- 
tions. In order to maintain the continuity of 
the work, the Department entered into a 
cooperative agreement first with the New 
Zealand Department of External Affairs and 
later with the New Zealand Department of 
Scientific and Industrial Research, to which 
the financial and technical control of the 
Observatory was transferred in 1929. 

Tucson Magnetic Observatory, United 
States. Complete and continuous registrations 
of atmospheric potential-gradient, of positive 
and negative air-conductivities, and of earth- 
currents were made at the Tucson Magnetic 
Observatory of the United States Coast and 
Geodetic Survey. Observer-in-Charge J. H. 
Nelson and assistants continued most effi- 
ciently this program made possible by the 
cooperation of the Coast and Geodetic Survey, 
the Bell Telephone Laboratories, and the De- 
partment. Table 15 summarizes the monthly 
and annual values of the atmospheric-electric 
elements, as computed by Mrs. G. Dewey, 
part-time assistant of the Department at Tuc- 
son. At Washington, Sherman continued the 
preparation of the data for publication. 

Hermanns Magnetic Observatory, South 
Africa. CIW magnetometer 17 with earth-in- 
ductor attachment continued in use at the Her- 
manus Magnetic Observatory. The Depart- 
ment cooperates here with the Trigonometrical 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



79 



TABLE 14 

Potential-gradient and meteorological summary, Apia Observatory, 1941 



Month 



Potential- 
gradient 



No. 
zero- 
days 



Value 

(v/m) 



Meteorological elements 



Pressure 
(mb) 



Temp. 
(°F) 



Rainfall 
(in.) 



Rel. 

hum. 

9 A.M. 

(per 
cent) 



Sunshine 
(hrs.) 



Wind 

velocity 

(miles/ 

hr.) 



January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November. 5 

December 

Totals and means 



10 

4 
6 
11 
15 
18 
13 
18 
11 
18 
16 
6 



120* 

136 

128 

118 

116 

132f 

129 

122 

123 

118 

146 

134 



1008. 

1005. 

1008. 

1009. 

1010. 

1011. 

1012.1 

1011.1 

1011.4 

1010.2 

1008 . 7 

1008.4 



81 
82 
81 
82 
81 
80 
78 
79 
79 
79 
80 
81 



6.76 
20.20 
12.56 



43 
62 
29 
07 
95 
35 
25 



6.93 
6.07 



77 
82 
78 
79 
78 
77 
76 
79 
77 
71 
75 
79 



228.2 
154.3 
246.3 
241.3 
218.1 
240.0 
211.3 
247.9 
234.8 
248.7 
248.0 
232.2 



146 



127 



1009.7 



80.2 



80.48 



77 



2751.1 



4.8 
7.2 
6.7 
7.8 
7.2 
6.8 
9.7 
8.6 

10.6 
7.8 

10.4 
7.1 



7.9 



* Based on mean of 9 zero days, 
t Based on mean of 16 zero days. 



TABLE 15 



Preliminary monthly mean values of atmospheric-electric elements, 
Tucson Magnetic Observatory, 1941 



Month 



January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November 

December 

Totals and means . 



No. 

selected 

days 



Potential-gradient 



17 

18 
18 
23 
22 
26 
16 
16 
20 
25 
26 
24 



251 



Reduction- 
factor 



3i 



28 



22 



1.28 



Value 
(v/m) 



72.2 

66.3 
58.0 
48.5 
48.2 
51.2 
52.6 
55.6 
53.6 
49.7 
57.6 
71.0 



57.0 



Air-conductivity, unit 10 -4 ESU 



All 

complete 

days 



31 
26 
31 
28 
31 
28 
28 
29 
24 
26 
30 
26 



338 



x+ 



2.01 
2.03 
2.00 
2.19 
2.29 
2.58 
2.22 
2.21 
2.70 
2.70 
2.27 
2.00 



2.27 



77 
89 
82 
09 
22 
46 
01 



2.00 
2.45 
2.46 
2.10 
1.80 



2.09 



(X++X-) 



3.78 
3.92 
3.82 
4.28 
4.51 
5.04 
4.23 
4.21 
5.15 
5.16 
4.37 
3.80 



4.36 



(X+/X-) 



1.14 
1.07 
1.10 
1.05 
1.03 
1.05 
1.10 
1.10 
1.10 
1.10 
1.08 
1.11 



1.09 






8o 



CARNEGIE INSTITUTION OE WASHINGTON 



Survey of the Union of South Africa, of which 
Dr. A. Ogg is Magnetic Adviser. Contact was 
maintained through Dr. Ogg with the Eliza- 
bethville Observatory in Belgian Congo. 

Godhavn Observatory, Greenland. Because 
of the war, cooperation was extended to the 
Godhavn Observatory by providing mainte- 
nance supplies and instrumental replace- 
ments, in addition to carrying on the cosmic- 
ray program already under way there through 
collaboration with the Cosmic-Ray Commit- 
tee of the Institution. Thus it has been pos- 
sible to continue the whole valuable geo- 
physical program at this important station, 
which otherwise would have been inter- 
rupted by the impossibility of receiving sup- 
plies from Denmark. 

Christchurch Observatory, New Zealand. 
The collaboration in cosmic-ray recordings 
and compilations at the Amberley station of 
the Christchurch Observatory in New Zea- 
land was maintained. Supplies were fur- 
nished as necessary. 

Royal Alfred Observatory, Mauritius. The 
loan of CIW marine-inductor 4 was continued 
for the control of the vertical-intensity records. 

Teoloyucan Observatory, Mexico. Dr. J. 
Gallo, Director of the National Observatory 
of Mexico in Teoloyucan, continued the 
cosmic-ray recordings there. Necessary sup- 
plies for maintenance of the program were 
prepared and forwarded. 

United States Antarctic Expedition (1940— 
1941)- Physicist Roy G. Fitzsimmons, of 
the United States Department of the Interior, 
completed, as guest-investigator at the De- 
partment of Terrestrial Magnetism from July 
1 94 1 through June 1942, the compilations and 
discussion of the magnetic data obtained at 
the Little America Observatory and in the 
field during the United States Antarctic Ex- 
pedition of 1940— 1941. The manuscript is 
now in the hands of the Department of the 
Interior for publication. The final average 
magnetic elements at Little America III, West 
Base (not identical with the observatory-loca- 
tions of the Byrd Expeditions of 1929-1930 
and 1934— 1935) were for the epoch 1940.7 
(April 1940 to January 1941): declination, 



104 57^ east; horizontal intensity, 0.10050 
CGS unit; inclination, 81 ° 20' south (these 
values supersede preliminary values given in 
Year Book No. 40, p. 109). Unfortunately 
there appears to be some local disturbance 
in the region about Little America, at least 
in declination. The mean epochs and values 
obtained by the two earlier expeditions are: 
Little America I, declination (1930.0) 106 
49^4 east, horizontal intensity (1929.7) 
0.09042 CGS unit, inclination (1929.7) 82 
i7'9 south; Little America II, declination 
(1934.6) 106 33^2 east, horizontal intensity 
(1934.6) 0.09444 CGS unit, inclination 
(1934.6) 81 ° 53^6 south. The resulting rates 
of annual changes, reckoning east declination, 
horizontal intensity, and north inclination 
as positive, are: declination, 1930.0 to 1934.6, 
-3:5, and 1934.6 to 1940.7, -15:7 (?); 
horizontal intensity, 1929.7 to 1934.6, +90 
gammas, and 1934.6 to 1940.7, +99 gammas; 
inclination, 1929.7 to 1934.6, +5^0, and 
1934.6 to 1940.7, +5:5. 

Assistant Physicist Murray A. Wiener, of 
the United States Department of the Interior, 
also of the Expedition, as guest-investigator 
at the Department of Terrestrial Magnetism 
from July 3 to December 9, 1941 completed 
the compilation and discussion of the auroral 
observations made in 1940 (see Year Book 
No. 40, p. no). The manuscript is now also 
awaiting publication by the Department of 
the Interior. 

The cosmic-ray data obtained from cosmic- 
ray meters loaned by the Department of Ter- 
restrial Magnetism were compiled and dis- 
cussed by Korff (see Year Book No. 41, pp. 
97-98). 

The autumn general meeting of the Ameri- 
can Philosophical Society (November 21 and 
22, 1941), at Philadelphia, heard reports on 
the scientific results of the Expedition in a 
symposium on the "Interest of the United 
States in Polar Lands." The program of eleven 
papers included one by Fitzsimmons giving a 
preliminary report on the magnetic and seis- 
mic program, and one by Korff giving a re- 
port on the cosmic-ray results. 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



81 



PUBLICATIONS ON THE "CARNEGIE" DATA 



The series of volumes under the general 
title "Scientific Results of Cruise VII of 
the Carnegie during 1928-1929, under com- 
mand of Captain J. P. Ault" is now in 
course of publication. Three quarto vol- 
umes on biology will be distributed in July 
and September 1942. These are: "Bi- 
ology — I: The copepods of the plankton 
gathered during the last cruise of the 
Carnegie" (237 pages), by Charles B. Wil- 
son; "Biology — II: The oceanic Tintin- 
noina of the plankton gathered during the 
last cruise of the Carnegie" (163 pages), by 
Arthur Shackleton Campbell; and (by off- 
set printing) "Biology — III : Studies in the 
morphology, taxonomy, and ecology of the 
Peridiniales" (129 pages), by Herbert W. 
Graham. 

The next manuscripts in the series, mas- 
ter-copy now in preparation for direct off- 
set printing, are: "Meteorology — I: Mete- 
orological results of the last cruise of the 
Carnegie," by Woodrow C. Jacobs and 
Katherine B. Clarke-Hafstad; "Meteor- 
ology — II: Upper wind observations and 
results obtained on the last cruise of the 
Carnegie," by Andrew Thomson; "Physical 



Oceanography — I: Results within physical 
oceanography of the last cruise of the 
Carnegie," by Harald U. Sverdrup; and 
"Physical Oceanography — II: Marine bot- 
tom samples collected in the Pacific Ocean 
on the last cruise of the Carnegie," by 
Roger Randall Revelle. 

The decision to use the offset method of 
printing for the volumes other than Bi- 
ology I and Biology II will make for econ- 
omy of publication. This method will also 
permit earlier issue of the remaining mem- 
oirs of the series, publication of which, be- 
cause of the other urgent demands on the 
limited personnel of the Department, has 
had unfortunately to be so long delayed. 
This delay has been mitigated to some ex- 
tent by the fact that the original manu- 
scripts for the various reports, and ex- 
tracts therefrom, have been made avail- 
able from time to time for use and con- 
sultation by other investigators engaged in 
oceanographic research. Digests and sum- 
maries of the memoirs have also been pub- 
lished, as indicated in the bibliographies of 
publications listed in previous annual re- 
ports of the Department. 



INSTRUMENT-SHOP 



The work of the Instrument-Shop dur- 
ing the report-year totaled approximately 
30,800 man-hours, of which 9300 were de- 
voted to the construction of the cyclotron. 
Approximately 15,300 man-hours were for 
war purposes, and 6200 for construction 
of new equipment and experimental ap- 
paratus, repairs and improvements to in- 
struments and apparatus, buildings and 
grounds, and miscellaneous items. The 
total included some 2600 hours overtime. 
Steiner continued in charge, with the 
skilled assistance of Lorz, Haase, Ksanda, 
Fogel, A. Smith (retired), Balsam, Huff 
(to July 11, 1941), P. A. Johnson, Buy- 



nitzky, Caherty, Thomas (from July 28, 
1941), Niemeyer, Roes (to July 31, 1941), 
Schloer (from April 1, 1942), A. M. 
Schmidt (to December 31, 1941), F. R. 
Nichols (to September 10, 1941, and from 
June 15, 1942), and Garves (February 25 
to May 31, 1942). Building Superintendent 
Smallwood also assisted in the shop and 
looked after the burden, increased greatly 
by war operations, of maintenance of build- 
ings and site, with the effective assistance 
of Malvin and Quade. 

The main items of design and construc- 
tion were: three Gish-Hess ionization- 
chambers and one electrometer-housing at- 



82 



CARNEGIE INSTITUTION OF WASHINGTON 



tachment for use with these chambers; 
automatic auroral camera for use at Col- 
lege, Alaska; 24 new cams for the iono- 
spheric apparatus at College Observatory; 
two automatic voltage-controllers, one each 
for the Huancayo and Watheroo observa- 
tories; and some improvements in the 
self-justifying typewriter. Under mainte- 
nance may be mentioned numerous re- 
placement-parts for ionospheric apparatus 



at observatories, overhauling of two la 
Cour recorder-clocks for the Godhavn Ob- 
servatory, and repairs and adjustments to 
magnetometer-inductors 26 and 28 and 
earth-inductors 48 and 171. 

Because of the heavy demands made by 
war work, a one-story addition to the shop 
with 1800 square feet of floor space was 
completed. 



MISCELLANEOUS ACTIVITIES 



Some lectures, addresses, and contribu- 
tions to meetings and physics colloquia, not 
already mentioned or listed in the bibliog- 
raphy accompanying this report, may be 
noted as follows: Eleventh Arthur Lec- 
ture, Smithsonian Institution, February 26, 
1942, "The Sun and the Earth's magnetic 
field," by Fleming. American Geophysical 
Union at its annual meeting, April 4, 1942: 
"Researches in terrestrial magnetism and 
electricity at the Department of Terrestrial 
Magnetism, Carnegie Institution of Wash- 
ington, for year April 1941 to March 1942," 
by Fleming; "Abrupt daily changes in con- 
densation-nuclei," by Jones and Ledig; 
"Geomagnetic bays, their frequencies and 
current-systems," by H. B. Silsbee and E. 
H. Vestine; "Atmospheric-electric results 
from simultaneous observations over the 
ocean and at Watheroo, Western Austra- 
lia," by Wait. American Institute of Elec- 
trical Engineers, University of Maryland 
Branch, December 10, 1941, "Scientific ac- 
tivities at the Huancayo Magnetic Observa- 
tory of the Department of Terrestrial Mag- 
netism, Carnegie Institution of Washing- 
ton," by Wells. Engineers Club of Balti- 
more, Maryland, November 26, 1941, 
"Tagged atoms," by Cowie. National Cap- 
ital Amateur Astronomers Association, 
March 7, 1942, "Magnetic effects of the 
Sun," by McNish. Navy Yard Colloquium, 
Washington, April 1, 1942, "Fluctuations 



in the Earth's magnetism," by Vestine. 
Physics Colloquium of Washington: De- 
cember 10, 1941, "Astronomical theory of 
the ice-caps," and April 1, 1942, "The ro- 
tation of the stars," by Gamow. Philo- 
sophical Society of Washington, December 
6, 1941, "Great geomagnetic storms of the 
present sunspot-cycle," by McNish. Radio 
broadcast at College, Alaska (KFAR), 
December 30, 1941, "Northern lights," by 
Bramhall, Rainey, and Seaton. McNish 
prepared for publication in "The progress 
of science" an article on "Geomagnetism 
and geoelectricity." 

Members of staff took part in scientific 
meetings and organizations as officers and 
members and on special committees. Nat- 
urally the present emergency curtails such 
activities, but they are therefore the more 
important in that maintenance of scientific 
life, progress, and instruction is also of 
great importance to the war effort. So far 
as conditions have permitted, contacts were 
kept with geophysicists of the United Na- 
tions to insure preservation of the frame- 
work of those organizations, such as the 
International Union of Geodesy and Geo- 
physics, which must be depended upon for 
international scientific cooperation on the 
return of peace. Members of our staff have 
served the American Geophysical Union — 
the organization representing international 
relations for the United States through the 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



83 



National Research Council — in various 
capacities. 

Library. The falling off in the receipt 
of publications from Europe reported last 
year was further accentuated by the ex- 
tension of the war to countries which 
had not been directly engaged in hostilities 
prior to December 1941. Despite this, ac- 
cessions totaled 456, as compared with 
442 for the last report-year, bringing the 
total number of accessioned books and 
pamphlets to 26,659. As in former years, 
all articles in current periodicals bearing on 
subjects under investigation by the Depart- 
ment were catalogued. 

Librarian Harradon continued as co- 
editor of the Journal of Terrestrial Mag- 
netism and Atmospheric Electricity, deal- 
ing especially with the foreign contribu- 
tions, preparation of notes, reviews of 
books and reports, and annotated lists of 
recent publications on geomagnetism, geo- 
electricity, and allied subjects. His list of 
published papers by members of the De- 
partment to December 31, 1941 showed a 
total of 2162. Reprints of these papers were 
regularly distributed to interested institu- 
tions and individuals. During the latter 
part of the report-year, Harradon spent 
some time in study of the early works on 
terrestrial magnetism reproduced by G. 
Hellmann in his Rara magnetica, with a 
view to the possible publication of transla- 
tions or modernized versions of some of 
these documents as a contribution to the 
history of geomagnetism. 

Dove continued as Secretary to the Di- 
rector and had charge of the general files 
of the Department and the storage and 
distribution of reprints. He typed a large 
number of reports and manuscripts, and 
prepared for binding the "Contributions" 
from the Department for 1941. 

Harradon continued as Secretary of the 
Section of Meteorology of the American 
Geophysical Union and as Chairman of the 



Committee on Statutes and By-Laws of the 
Union. A biographical sketch of the late 
Dr. Louis A. Bauer, first Director of the 
Department of Terrestrial Magnetism, was 
prepared for the Dictionary of American 
biography. 

As in the past, the facilities of the li- 
brary were made available to research 
workers and students from educational in- 
stitutions and government bureaus. More 
than in any previous year, the library has 
been used by specialists, particularly by 
those engaged on problems concerned with 
the war. Information on geomagnetism 
and allied subjects was freely furnished in 
response to a large number of letters ema- 
nating from diverse sources. The practice 
of interlibrary loans was continued, and 
reciprocal and cordial relations were main- 
tained with other libraries, particularly 
with the Library of Congress. 

Office administration. The war work 
undertaken for the government under con- 
tracts with the Office of Scientific Research 
and Development and the Navy Depart- 
ment has required most of the regular time 
and a great deal of overtime in correspond- 
ence, placing of orders, accounting, and 
matters concerned with the activities of 
over 200 added temporary employees. Air- 
raid instructions were prepared by M. B. 
Smith, Steiner, Smallwood, and Scott. 
Much time was required in connection 
with war-work procedures, contracts, re- 
quests for priorities, and transfers of per- 
sonnel. The procedures for maintaining 
the usual departmental activities, both in 
Washington and at the three observatories, 
were complicated also by the emergency 
conditions and required much more time 
than ordinarily is the case. 

The many details involved in the prac- 
tically fivefold expansion of administration 
and personnel were most efficiently han- 
dled by M. B. Smith, administrative as- 



8 4 



CARNEGIE INSTITUTION OF WASHINGTON 



sistant, and the members of the regular 
and temporary clerical staff. 

Capello, secretary and property-clerk, 
had charge of shipments and inventory, 
maintained detailed monthly statements 
of time and costs of work in the shop, 
and prepared manuscripts. The drawings, 
charts, and illustrations for publications 



and reports were prepared by Hendrix. 
He and J. W. Green also handled the 
photographic work. The records received 
from the observatories and field were 
arranged and filed by Miss Balsam, who 
with Capello kept current the cataloguing 
of photographic films and index-albums 
of prints. 



BIBLIOGRAPHY 



Adams, W. S., J. A. Fleming, and F. E. Wright. 
Progress-report of Committee on Coordina- 
tion of Cosmic-Ray Investigations for the 
period July 1940 to June 1941. Carnegie 
Inst. Wash. Year Book No. 40, pp. 1 17-120 
(1941). 

Bartels, J. Internationale erdmagnetische Char- 
akterzahlen im Jahre 1940. Terr. Mag., vol. 

46, PP- 345-346 (194O; 

Erdmagnetisch ruhige und gestorte Tage 

im zweiten Halbjahr 1940. Terr. Mag., vol. 

46, pp. 366-367 (1941). 

Booker, H. G. Height of maximum electron- 
density in the ionosphere. Terr. Mag., vol. 

47, P- 173 (l942). 

Breit, G. Proton-proton scattering. Univ. Penn- 
sylvania Bicentennial Conf., Nuclear Physics, 
pp. 5-19 (1941). 

Brode, R. B. See report of Committee on Co- 
ordination of Cosmic-Ray Investigations, 
Carnegie Inst. Wash. Year Book No. 41, 
p. 90 (1942). 

Chapman, S. Charles Chree and his work on 
geomagnetism. (Abstract) Nature, vol. 148, 

PP- 153-157 (i94i)- 

The Sun and the ionosphere. Jour. Inst. 

Elec. Eng., vol. 88, pp. 400-413 (1941). 

Edmond Halley as physical geographer, 

and the story of his charts. Occas. Notes, 
Roy. Astron. Soc, No. 9, pp. 122-134 (1941). 

Greenwich frequency-statistics of geo- 
magnetic disturbance. Terr. Mag., vol. 46, 
pp. 385-400 (1941). 

First Charles Chree address. I: Charles 

Chree and his work on geomagnetism; II: 
Geomagnetic time-relationships; III: The 
future of world magnetic surveying. Proc. 
Phys. Soc, vol. 53, pp. 629-657 (1941). 

Notes on isomagnetic charts. VI: Earth- 
air electric currents and the mutual consist- 
ency of H and D isomagnetic charts. Terr. 
Mag., vol. 47, pp. 1-13 (1942)- 



— Notes on isomagnetic charts. VII: Mathe- 
matical notes on isoporic charts and their 
singular points. Terr. Mag., vol. 47, pp. 115- 
138 (1942). 

— Notes on isomagnetic charts. VIII: The 
mutual consistency of the declination and 
horizontal-intensity isoporic charts. Terr. 
Mag., vol. 47, pp. 139-146 (1942). 

and A. M. Mian. The rate of ion-produc- 



tion at any height in the Earth's atmosphere. 
Terr. Mag., vol. 47, pp. 31-44 (1942). 
Coile, R. C. Ionospheric characteristics at 
Huancayo, Peru, for the year 1940. Terr. 
Mag., vol. 46, pp. 435-442 (1941). 

See Ledig, P. G. 

Compton, A. H. See report of Committee on 
Coordination of Cosmic-Ray Investigations, 
Carnegie Inst. Wash. Year Book No. 41, 
p. 94 (1942). 

Cowie, D. B., and G. K. Green. A high vacuum 
valve. Rev. Sci. Instr., vol. 12, p. 556 (1941). 

Cynk, B. Some relationships in the fields of geo- 
magnetic storms. Terr. Mag., vol. 46, pp. 

431-433 (i94i)- 

Fitzsimmons, R. G. Preliminary report on the 
magnetic and seismic program. (United 
States Antarctic Expedition of 1939-41.) 
(Abstract) Science, vol. 94, p. 549 (1941). 

Fleming, J. A. Researches in terrestrial mag- 
netism and electricity at Department of Ter- 
restrial Magnetism, Carnegie Institution of 
Washington, for year April 1940 to March 
1941. Amer. Geophys. Union, 22d annual 
meeting, pt. II, pp. 462-466 (1941). 

Terrestrial magnetism and electricity. 

Amer. Year Book for 1941, pp. 740-747 
(1942). 

Summary of the year's work to June 30, 

1941, Department of Terrestrial Magnetism, 
Carnegie Institution of Washington. Terr. 
Mag., vol. 47, pp. 45-52 (1942). 



DEPARTMENT OF TERRESTRIAL MAGNETISM 



85 



Fleming, J. A. (ed.). Transactions of the Ameri- 
can Geophysical Union, twenty-second an- 
nual meeting, April 30 to May 3, 1941, Wash- 
ington, D. C. Joint regional meeting, South 
Pacific Coast Area, Sacramento, California, 
January 194 1, reports and papers, (A) Sec- 
tion of Hydrology, (B) Western Interstate 
Snow-Survey Conference. 3 pts., 1035 pp. 
Washington, National Research Council 
(1941). 

See Adams, W. S.; Gamow, G.; Tel- 
ler, E. 

Forbush, S. E., and Lange, I. See report of 
Committee on Coordination of Cosmic-Ray 
Investigations, Carnegie Inst. Wash. Year 
Book No. 41, p. 94 (1942). 

Gamow, G., and J. A. Fleming. The eighth an- 
nual Washington Conference of Theoretical 
Physics. Science, vol. 95, pp. 579-581 (1942). 

See Teller, E. 

Gish, O. H., and M. L. Phillips. Errors in 
measurements of condensation-nuclei. Trans. 
Amer. Geophys. Union, 22d annual meet- 
ing, pt. II, pp. 432-434 (1941). 

Graham, H. W. Plankton production in rela- 
tion to character of water in the open Pacific. 
Jour. Marine Res., vol. 4, pp. 189-197 (1941). 

Green, G. K. See Cowie, D. B. 

Harradon, H. D. The variations of geomag- 
netism. Sky and Telescope, vol. 1, pp. 12-17 
(1942). 

List of recent publications. Terr. Mag., 

vol. 46, pp. 379-383, 481-486 (1941); vol. 42, 
pp. 94-96, 182-184 ( x 94 2 )- 

Hess, V. F. Radioactivity of rocks and ionization- 
balance of the atmosphere. Terr. Mag., vol. 
46, pp. 409-415 (1941). 

See report of Committee on Coordina- 
tion of Cosmic-Ray Investigations, Carnegie 
Inst. Wash. Year Book No. 41, p. 96 (1942). 

Heydenburg, N. P., and N. F. Ramsey. The 
scattering of one- to three-Mev protons by 
helium. Phys. Rev., vol. 60, pp. 42-46 
(1941). 

Johnson, T. H. See report of Committee on 
Coordination of Cosmic-Ray Investigations, 
Carnegie Inst. Wash. Year Book No. 41, p. 
97 (1942). 

Johnston, H. F. International quiet and dis- 
turbed days for the first six months of 1941. 
Terr. Mag., vol. 47, p. 81 (1942). 

Three-hour-range indices, K, for twelve 

magnetic observatories, July to December, 
1940, and summary for 1940. Terr. Mag., 
vol. 46, pp. 301-308 (1941). 



American URSI broadcasts of cosmic 

data, giving American magnetic character- 
figure, C A , three-hour-range indices, K, and 
mean X-indices, K A , for April to June, 1941; 
cosmic data, giving American magnetic char- 
acter-figure, C A , three-hour-range indices, K, 
and mean i^-indices, K A , for July to Sep- 
tember, 1941; cosmic data, giving Ameri- 
can magnetic character-figure, C A , three- 
hour-range indices, K, and mean K-indices, 
K A , for October to December, 1941, and 
summary for year 1941; cosmic data, giving 
American magnetic character-figure, C A , for 
January to March, 1942, three-hour-range 
indices, K, and mean X-indices, K A , for 
October, 1941, to March, 1942. Terr. Mag., 
vol. 46, pp. 360-364, 465-468 (1941); vol. 
47, PP- 67-74, 159-164 (1942). 

Jones, M. W. See Ledig, P. G. 

Korff, S. A. See report of Committee on Co- 
ordination of Cosmic-Ray Investigations, 
Carnegie Inst. Wash. Year Book No. 41, p. 

99 (1942). 

Lange, I. See Forbush, S. E. 

Ledig, P. G. Principal magnetic storms, Huan- 
cayo Magnetic Observatory, April to June, 
194 1 ; July to September, 194 1; October to 
December, 1941; January to March, 1942. 
Terr. Mag., vol. 46, pp. 370-371, 475-476 
(1941); vol. 47, pp. 87, 179 (1942). 

R. C. Coile, and M. W. Jones. The 

ionosphere at Huancayo, Peru, April to 
June, 1941; July to September, 1941; October 
to December, 1941. Terr. Mag., vol. 46, pp. 
35i-354> 443-446 (194O; vol. 47, pp. 63-66 
(1942). 

McNish, A. G. Geomagnetic survey of the vol- 
canic areas of Guatemala. Trans. Amer. 
Geophys. Union, 22d annual meeting, pt. II, 
pp. 508-512 (1941). 

Auroral display and geomagnetic storm 

of September 18-19, 1941. Science, vol. 94, 
pp. 413-414 (1941); Jour. Roy. Astron. Soc. 
Canada, vol. 35, pp. 368-370 (1941). 

The great geomagnetic storm of Septem- 
ber 18-19, I 94 I - Sci. Month., vol. 53, pp. 
478-481 (1941). 

The aurora and geomagnetic storm of 



September 18-19, I 94 I - Terr. Mag., vol. 

46, pp. 461-463 (1941). 
Mian, A. M. See Chapman, S. 
Millikan, R. A. See report of Committee on 

Coordination of Cosmic-Ray Investigations, 

Carnegie Inst. Wash. Year Book No. 41, 

p. 102 (1942). 



86 



CARNEGIE INSTITUTION OF WASHINGTON 



Parkinson, W. C. The ionosphere at Watheroo, 
Western Australia, April to June, 1941; July 
to September, 194 1. Terr. Mag., vol. 46, pp. 
347-350, 447-450 (1941). 

Principal magnetic storms, Watheroo 

Magnetic Observatory, April to June, 1941; 
July to September, 1941; October to Novem- 
ber, 1941; December, 1941. Terr. Mag., vol. 
46, pp. 371-372, 477-478 (i94i)5 vol. 47, 
pp. 89, 180 (1942). 

Phillips, M. L. See Gish, O. H. 

Powell, W. M. See report of Committee on Co- 
ordination of Cosmic-Ray Investigations, 
Carnegie Inst. Wash. Year Book No. 41, 
p. 102 (1942). 

Ramsey, N. F. See Heydenburg, N. P. 

Sapsford, H. B. Principal magnetic storms, Apia 
Observatory, July to December, 1941; Janu- 
ary to March, 1942. Terr. Mag., vol. 47, pp. 
87-88, 179-180 (1942). 

Seaton, S. L. A multiband end-fed antenna. 
QST, vol. 25, pp. 52-53 (1941). 

Sherman, K. L. Comparison of methods for 
computing air-earth current. Terr. Mag., 
vol. 46, pp. 401-407 (1941). 

Teller, E., G. Gamow, and J. A. Fleming. The 
seventh annual Washington Conference of 
Theoretical Physics, May 22-24, x 94 x - 
Science, vol. 94, pp. 92-94 (1941). 

Torreson, O. W. See Wait, G. R. 

Vestine, E. H. The reduction of magnetic ob- 
servations to mean of year. (Abstract) 
Trans. Amer. Geophys. Union, 22d annual 
meeting, pt. II, p. 441 (1941). 

The reduction of magnetic observations 

to epoch. I. Terr. Mag., vol. 47, pp. 97- 
113 (1942). 



Wait, G. R., and O. W. Torreson. Atmospheric- 
electric results from Watheroo, Western 
Australia, for the period 1924-1934. Terr. 
Mag., vol. 46, pp. 3 IQ -34 2 094 1 )- 

Diurnal variation in electrical re- 
sistance of the vertical column of the atmos- 
phere at Watheroo, Western Australia. (Ab- 
stract) Trans. Amer. Geophys. Union, 22d 
annual meeting, pt. II, p. 453 (1941). 

Wells, H. W. Ionospheric investigations at 
Huancayo Magnetic Observatory (Peru) 
with application to wave-transmission condi- 
tions. (Abstract) Proc. Inst. Radio Eng., 
vol. 29, p. 667 (1941). 

Earth's magnetic field and actual heights 

in the ionosphere. Terr. Mag., vol. 47, pp. 

75-79 (1942). 

Effects of solar activity on the ionosphere 



and radio communication. (Abstract) Proc. 
Inst. Radio Eng., vol. 30, p. 254 (1942). 
Wright, F. E. See Adams, W. S. 

Reviews 

Harradon, H. D. American Geophysical Union, 
Transactions of 1941, edited by J. A. Flem- 
ing. (Rev.) Terr. Mag., vol. 46, pp. 433-434 
(1941). 

Benjamin Franklin's experiments: a new 

edition of Franklin's "Experiments and ob- 
servations on electricity," by I. B. Cohen. 
(Rev.) Terr. Mag., vol. 47, p. 30 (1942). 

Discussion of aurora observations, April- 
September 1940, United States Antarctic Ex- 
pedition, Little America, 1939-1941, by M. A. 
Wiener. (Rev.) Terr. Mag., vol. 47, pp. 
79-80 (1942). 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 

Committee on Coordination of Cosmic-Ray Investigations. Progress report for 
the period July 1941 to June 1942. (For previous reports x see Year Books Nos. 32-40.) 



With the entry of the United States into 
World War II, activities in cosmic-ray re- 
search have been necessarily reduced be- 
cause of (a) diversion of personnel to 
war-research problems, (b) impossibil- 
ity of continuing relations with workers 
and observatories other than those of the 
United Nations, and (c) curtailment of 
laboratory facilities and of equipment and 
transportation for field-work. Good prog- 
ress was nevertheless made during the year 
ended June 30, 1942, as is evidenced by 
the appended reports of investigators with 
whom the Committee has been privileged 
to cooperate through the support of the 
Carnegie Institution of Washington and 
the Carnegie Corporation. 

There is not the slightest doubt among 
physicists that the generous and continued 
support accorded the program of cosmic- 
ray research during the past decade has 
added greatly to knowledge and has en- 
couraged "in the broadest and most liberal 
manner investigation, research, and dis- 
covery." The field of cosmic-ray research 
presents appeal and fascination similar to 
those found in the outstanding astronomi- 
cal studies carried on at the Mount Wilson 
Observatory and so generously supported 
without undue emphasis upon possible 
"practical" applications. The cosmic-ray 
program has forwarded discoveries of the 
positron, of the mesotron, and of pair- 
production as a form of energy-production 
into matter, and information on electro- 
dynamics of the interaction of high-energy 
electrons, gamma rays, mesotrons, protons, 

1 For statement on formation, purposes, and 
policies of the Committee see Year Book No. 38 
(1938-1939), pp. 335-349. 



and alpha particles with atomic nuclei. 
But the further support of the program 
should be based on what is not known 
about cosmic rays rather than on what is 
known about them. Among outstanding 
questions in this field are: (1) the source 
of cosmic radiation; (2) the nature of the 
primary radiation; (3) the method of pro- 
duction of mesotrons; (4) the nature of 
the mesotron; and (5) the interaction of 
matter with extremely high-energy par- 
ticles. 

In a memorandum on "The purposes of 
cosmic-ray investigation," prepared in Jan- 
uary 1942 at the request of the President 
of the Carnegie Corporation, Dr. S. A. 
Korff comments on certain aspects of this 
field. Extracts from that memorandum 
follow : 

"The origin of cosmic rays is at the present 
time a mystery. It is evidently tied up with 
the larger aspects of the universe, and it will 
almost certainly be some time before we 
understand it fully. On the other hand this 
in itself provides an intriguing spur to the 
initiative of investigators. Since tne cosmic 
rays are so abundant and so powerful and 
since they appear to come from all directions 
in space regardless of whether or not these 
regions are occupied by matter, it seems quite 
possible that the cosmic rays will eventually 
help to throw some light on the now com- 
pletely unanswerable questions such as how 
long has the universe been here, how long 
may it be expected to continue, how is it 
supplied with energy, and how much of this 
energy is left. 

"In the realm of high-energy physics cosmic 
rays provide the only means for research at 
energies greater than those produced by cyclo- 
trons. The present 225-ton cyclotrons generate 
energies in the neighborhood of 30 million 

87 



88 



CARNEGIE INSTITUTION OF WASHINGTON 



electron-volts. The one under construction 
in California is expected to produce one hun- 
dred million electron-volts and possibly 
more — an energy which should be just enough 
to generate mesotrons in the laboratory. Until 
this large cyclotron is completed, cosmic rays 
will provide the only means for studying 
these particles; even after it is completed the 
cosmic rays will provide the only means for 
studying any but the very slowest mesotrons. 
The cyclotron now under construction repre- 
sents doubtless the practical limit which will 
not be exceeded for many years to come. The 
whole energy-range beyond this limit is ac- 
cessible only through cosmic rays. 

"Cyclotrons have been of the utmost im- 
portance in developing a new field of physics. 
They were able to produce radiation with 
the same energy as that with which the nuclei 
of atoms are held together. In other words, 
energies produced by the cyclotron and nu- 
clear-binding energies are comparable. The 
particles accelerated by cyclotrons can pene- 
trate therefore into nuclei and produce trans- 
mutations and other nuclear changes. A vari- 
ety of new elements, many of them of the 
utmost value in medicine and others usable 
as tracers in complex biological, chemical, and 
physiological reactions have been thus pro- 
duced. The next big field to be explored in 
physics is that in which the bombarding 
energies are much greater than the binding 
energies of the nuclei. The only tool of re- 
search in this field is cosmic-ray investigation. 
Large factors are available in the energies 
which may be observed .... These energies 
are sufficient to disrupt atoms completely, and 
to permit study of the forces and laws which 
are at work in their interiors .... At the 
present time we can produce million-volt 
x-rays, and use them for medical treatments. 
To know what the effect of a billion-volt 
x-ray will be, we must turn to cosmic rays, 
which can and do produce such rays and have 
already revealed some of the properties 
possessed by them. In this field cosmic 
rays . . . promise to reveal much about the 
structure of matter. 

"In the possibly 'practical' realm, cosmic 
rays are already beginning to be an important 



adjunct in meteorology. Since the cosmic 
rays come from outer space and are absorbed 
in the atmosphere through which they pass 
the intensity at sea-level depends on the 
amount of air above the instrument, and 
hence on the atmospheric pressure. The 
cosmic-ray mesotrons also experience a type 
of absorption due to 'decay,' since they are 
unstable and spontaneously disintegrate. This 
decay depends on time and hence on the 
length of the path over which they pass. 
Hence the cosmic-ray intensity depends not 
only on the amount of the atmosphere but 
also on its distribution, since if the air is 
warmer, the total atmosphere will expand 
and the mesotrons which are almost all pro- 
duced near the top of the atmosphere will 
decay more because of having to travel 
further. Consequently a study of cosmic rays 
gives the meteorologist a picture of what 
may be happening at altitudes even higher 
than those accessible to sounding balloons. 

"... It is well known that disturbances 
on the sun's surface produce magnetic storms 
and concomitant radio fade-outs and disloca- 
tions in wire telegraphy and telephony .... 
These same storms also affect the intensity 
of the cosmic rays, especially since the cosmic 
rays depend on the earth's magnetic field. 
The cosmic rays will provide therefore an 
additional technique for studying the earth's 
magnetic field and the changes in it which 
result from magnetic storms . . . ." 

Statements of progress from investiga- 
tors and organizations with whom the 
Committee has cooperated actively are 
appended to this report. The study on mo- 
tion of cosmic-ray particles in the geo- 
magnetic field by Professor M. S. Vallarta 
at Massachusetts Institute of Technology 
remains at a virtual standstill because of 
delay in completion of the differential ana- 
lyzer and of limitations imposed by the 
war. The following paragraphs briefly 
summarize results and progress during the 
year ended June 30, 1942. 

Investigations. Despite the demands of 
the emergency and consequent depletion 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



8 9 



of personnel, Professor A. H. Compton 
succeeded in maintaining an effective 
group for the studies of cosmic rays at 
the University of Chicago. Of special in- 
terest were the results of the mountain 
experiments showing the production of 
mesotrons by photons and protons, and 
of the study of the production of mesotrons 
near the top of the atmosphere by incom- 
ing protons. Apparently there was demon- 
strated for the first time, in the production 
of mesotrons by photons traversing mat- 
ter, the interaction of electrical and nuclear 
forces. 

S. E. Forbush, on leave of absence dur- 
ing the entire year on a war-research 
assignment, found time for general super- 
vision, at the Department of Terrestrial 
Magnetism, of the compilations and de- 
tails of maintenance of the cosmic-ray 
meters at the Cheltenham, Huancayo, Teo- 
loyucan, Christchurch, and Godhavn ob- 
servatories. Communication with Green- 
land became more difficult, but, through 
the courtesy of the Consul-General of 
Denmark at New York, the American- 
Danish Greenland Commission, and the 
United States Coast Guard, the necessary 
supplies, batteries, and replacements for 
operation and maintenance were for- 
warded from the Department of Terres- 
trial Magnetism. 

Miss Isabelle Lange continued the reduc- 
tion and analysis of the photographic rec- 
ords from observatories despite the neces- 
sity of giving a considerable part of her 
time to computations concerned with war 
research. The cosmic-ray variations asso- 
ciated with the magnetic storm of March 
1, 1942 afford a good example of the need 
of continued photographic registrations at 
widely separated stations. 

Professor Victor F. Hess and associates 
at Fordham University corroborated the 
view that the so-called temperature-effect 



of cosmic rays is primarily an effect of at- 
mospheric mass-distribution variations. 

At the Bartol Research Foundation, Dr. 
Thomas H. Johnson, R. P. Shutt, and 
Sergio de Benedetti made progress on con- 
struction of the large high-pressure Wilson 
cloud-chamber. They completed the analy- 
sis of investigations of the composition 
of the cosmic radiation in the lower atmos- 
phere, and of the processes of interaction 
of cosmic rays with matter. 

Professor S. A. Korff, now at New York 
University, from analysis of the cosmic- 
ray data obtained on the United States 
Antarctic Service Expedition during 1940, 
found that the fluctuations in cosmic-ray 
intensity correlated somewhat better with 
changes in the temperature of the upper 
atmosphere than with those at sea-level. 
From experiments at Swarthmore, in Den- 
ver, and on the summit of Mount Evans, 
it was found that a large percentage of 
neutrons were associated with cosmic-ray 
showers. 

Dr. Robert A. Millikan and his associ- 
ates and students at the California Insti- 
tute of Technology made tests at various 
stations in Mexico and in the United States 
as to the origin of cosmic-ray energies, 
and obtained results apparently confirming 
the hypothesis proposed in the report of 
last year. The 60-cm high-resolution cloud- 
chamber for study of the properties of 
mesotrons was completed. Improvements 
of cosmic-ray Geiger counters and studies 
of their mechanisms were made. 

Wilson M. Powell and C. E. Nielsen, at 
the University of California, studied the 
mass of the mesotron and prepared special 
equipment for tests to be made at Mount 
Evans during July and August 1942. 

The Committee kept contacts by corre- 
spondence and personal conference with 
many investigators. Grateful acknowledg- 
ment is made to the directors and staff- 



9 o 



CARNEGIE INSTITUTION OF WASHINGTON 



members of the organizations which con- 
tinued their contributions and services to 
the program; these include the Danish 
Meteorological Institute, the National As- 
tronomical Observatory of Mexico, the 
New Zealand Department of Scientific and 
Industrial Research, and the United States 
Coast and Geodetic Survey. 

W. S. Adams 

J. A. Fleming, Chairman 

F. E. Wright 

Cosmic-Ray Magnet 

Robert B. Brode 
University of California, Berkeley, California 

The pressure of war research has pre- 
vented further work on the study of meso- 
trons with the magnet of the Carnegie 
Institution at the University of California. 
The magnet has been, however, in nearly 
continuous use since December 1941 as 
an essential instrument in a war-research 
problem. The design of the magnet was 
fortunately such that it could be used with- 
out alteration for this purpose. 

BIBLIOGRAPHY 

Brode, R. B. Cosmic-ray ionization. (Abstract) 
Jour. Washington Acad. Sci., vol. 31, pp. 
378-379 (1941). 

Report on Cosmic-Ray Research at the 
University of Chicago 

A. H. Compton 
University of Chicago, Chicago, Illinois 

Mountain experiments. During the year 
1941-1942 high-altitude experiments on 
mountains have been performed at stations 
in Peru and Colorado. 

The work by E. O. Wollan and Donald 
Hughes at the San Cristobal Mine (4750 
meters) near Lima, and of Norman Hil- 
berry and Ann Hepburn Hilberry on El 
Misti (5840 meters) near Arequipa, was 



mentioned in last year's report. The per- 
sons engaged on these studies were as- 
signed to other urgent work before more 
than a preliminary analysis of their results 
could be prepared. This analysis was, how- 
ever, sufficient to establish the presence of 
both protons and mesotrons of intermedi- 
ate energy at these altitudes, and to confirm 
the very high energy (up to io 16 electron- 
volts) of the primary particles responsible 
for the "giant showers" that become promi- 
nent at the higher altitudes. 

On Mount Evans, in 1941, David B. Hall 
and Marcel Schein studied the energy dis- 
tribution of mesotrons. Using four coun- 
ter-telescopes, it was possible to obtain the 
energy-spectrum of mesotrons with good 
precision. Using a tray of Geiger-Miiller 
counters, a method was developed for dis- 
tinguishing between slow mesotrons and 
electrons. This arrangement made it pos- 
sible to obtain the spectrum of low-energy 
mesotrons by pure absorption methods. 
The spectrum shows, at the elevation of 
4340 meters, a pronounced maximum at an 
energy of about 3 X 10 8 electron-volts, 
whereas at sea-level the corresponding 
maximum occurs at an energy of about 
io 9 electron-volts. Such a change in the 
spectrum of the mesotron had been quali- 
tatively observed in the airplane experi- 
ments of Schein, Wollan, and Groetzinger 
at altitudes of 7500 meters. Theoretical 
calculations indicate that at least a large 
part of the slow mesotrons observed at 
Mount Evans must have been produced at 
altitudes very close to the place where the 
apparatus was located. 

Victor H. Regener constructed a counter- 
outfit to study the production of mesotrons. 
His apparatus consisted of about 150 coun- 
ter-tubes arranged in trays. Different thick- 
nesses of lead (up to 35 cm) were inter- 
posed between the counter-trays. Each 
individual counter-tube was connected to 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



9* 



a neon-flasher indicating the passage of an 
ionizing particle through the counter. 
Working first at Mount Evans, Regener 
obtained about 100,000 pictures, each show- 
ing at least one cosmic-ray particle travers- 
ing the counter-set. Several hundred of 
these pictures show definite evidence of 
production of mesotrons in the material 
interposed between the counters. 

At altitudes of 4000 meters, 90 per cent 
of the mesotrons are produced by non- 
ionizing rays and 10 per cent by ionizing 
particles. Two kinds of production-proc- 
ess were found: (a) There exists a pro- 
duction of single mesotrons with energies 
of about io 8 electron-volts by non-ionizing 
rays which seem to be photons. No 
process has previously been observed in 
which a direct interaction occurs between 
the electromagnetic and the nuclear field 
of force. Undoubtedly the nuclear produc- 
tion of a slow mesotron by a photon would 
represent such a process. A further study 
of this phenomenon is in preparation, (b) 
Three per cent of the pictures obtained 
on Mount Evans show a multiple produc- 
tion of mesotrons. These mesotrons origi- 
nate mostly from a penetrating neutral 
radiation. The number of counter-tubes 
simultaneously discharged indicates an av- 
erage multiplicity of 6 to 8 mesotrons per 
producing particle. The mesotrons pro- 
duced are capable of penetrating a lead 
thickness of about 20 cm, which corre- 
sponds to an average mesotron energy of 
3 X io 8 electron-volts. This process seems 
similar in nature to the multiple produc- 
tion of mesotrons by protons found by 
Schein, Jesse, and Wollan (1941) close to 
the top of the atmosphere. 

Marcel Schein and David B. Hall meas- 
ured the zenith-angle distribution of mes- 
otrons and electrons. It was found that 
the slow mesotrons have a different zenith- 
angle distribution from that of electrons 
and fast mesotrons. Schein and Hall con- 



clude that the soft component does not 
originate from electrons entering the 
earth's atmosphere, but from the decay 
of high-energy mesotrons. 

The east-west asymmetry of mesotrons 
was studied by Schein and Hall on Mount 
Evans. An excess of 2 per cent from the 
west was observed. T. H. Johnson has 
tried to explain the high-altitude asym- 
metry by a bending of the paths of meso- 
trons by the earth's magnetic field. The 
excess of positives present in the spectrum 
of mesotrons leads to a slight directional 
asymmetry. The magnitude of the effect 
found on Mount Evans indicates an av- 
erage path of these mesotrons between 20 
and 30 km. This means that they must 
have been produced close to the top of the 
atmosphere. 

Variations in the vertical intensity of 
mesotrons and electrons were compared 
with barometric changes by Schein and 
Hall on Mount Evans. For high-energy 
mesotrons the barometer-effect was found 
to be of the order 5 per cent per cm of 
mercury. For slow mesotrons with an en- 
ergy of io 8 electron-volts the barometer- 
effect was as large as 25 per cent. The low- 
energy mesotrons are also strongly in- 
fluenced by magnetic disturbances, a phe- 
nomenon which was noticed on Mount 
Evans during the magnetic storm on Sep- 
tember 18, 1 94 1. 

W. H. Bostick, using a cloud-chamber 
in the field of a permanent magnet, ana- 
lyzed the nature of low-energy particles 
emerging below 2 cm of lead. In addition 
to the usual shower pictures, a relatively 
large number of simple mesotron-tracks 
were obtained. Many of them show defi- 
nite curvature in a field of 1200 gauss, 
which means that their energy is below 
5 X io 8 electron-volts. The relative num- 
ber of these mesotrons is in accordance 
with the energy-spectrum of mesotrons 
found on Mount Evans. 



9 2 



CARNEGIE INSTITUTION OF WASHINGTON 



Working at Climax, Colorado, in De- 
cember, V. H. Regener and R. Lapp stud- 
ied the production of mesotrons in differ- 
ent materials (paraffin, aluminum, iron, 
and lead). These experiments show that 
in light materials the number of meso- 
trons produced by non-ionizing radiation 
is much higher than had been expected. 
In all the materials several mesotrons are 
produced simultaneously with an average 
multiplicity of 6 to 8. The cross-section of 
the production-process was found to be 
equal to the area of the nucleus hit by the 
primary particle. The mesotron produc- 
tion-process found in the stratosphere has 
also a cross-section of nuclear dimensions. 
It thus seems well established that the pro- 
duction of mesotrons is a nuclear process. 

P. Pompeia and E. O. Wollan con- 
structed a counter-outfit to measure the 
lifetime of the mesotron by a time-delay 
experiment. The apparatus was similar 
to that used by Rasetti in Canada. After 
extensive tests on the ground, the appa- 
ratus was set up by Pompeia and Lapp 
at Echo Lake (Colorado) and later on top 
of Mount Evans. The experiments are 
not yet completely analyzed. The prelimi- 
nary results, however, indicate that several 
mesotrons were stopped in the absorber 
without giving out a decay-electron in the 
time-interval of i to 15 microseconds after 
they were stopped. It would be prema- 
ture to conclude that the mesotron is di- 
rectly captured by the nucleus, or that the 
average lifetime of the mesotron within 
the solid absorber is much shorter than 
as measured by Rossi and his collaborators, 
until further tests are made. 

Time-variations of cosmic rays. By cour- 
tesy of the Department of Terrestrial Mag- 
netism of the Carnegie Institution, the 
model-C recording cosmic-ray meters at 
Christchurch (New Zealand), Huancayo 
(Peru), Teoloyucan (Mexico), Chelten- 
ham (Maryland, United States), and God- 



havn (Greenland) have been kept in oper- 
ation. Other work has prevented full at- 
tention to their analysis. It is hoped, how- 
ever, that the program of observation, 
intended to operate through a sunspot- 
cycle, may be completed. 

N. F. Beardsley has assembled a counter- 
apparatus of large sensitive area for stud- 
ies of time-variations in cosmic-ray inten- 
sity on the ground. This apparatus is now 
in operation and data are being continu- 
ously collected. 

Victor H. Regener is constructing five 
identical counter-outfits which it is planned 
to station permanently at five different 
places in the United States. Each of these 
outfits can be used to measure the changes 
in vertical intensity of mesotrons with at- 
mospheric pressure and temperature. 

Composition of cosmic rays. Marcel 
Schein and M. Jona have sent counter- 
outfits carried by balloons into the strato- 
sphere to study the neutral component of 
cosmic radiation. It was found that within 
an experimental error of about 2 per cent 
there is no multiple production of meso- 
trons by neutral rays present close to the 
top of the atmosphere. This means that in 
the stratosphere the number of high-energy 
neutrons, if any, must be very small. The 
apparatus used was also capable of register- 
ing large showers generated in lead by a 
high-energy neutral radiation. The ab- 
sence of these showers strongly indicates 
that there cannot be any appreciable 
amount of high-energy Y-radiation enter- 
ing the earth's atmosphere from the out- 
side. These results confirm the absence 
of high-energy neutral rays entering the 
atmosphere. 

E. Dershem and M. Schein developed a 
new type of balloon counter-outfit which 
can be used for cosmic-ray studies in the 
stratosphere. In this outfit the coincidence- 
counts of four different counter-telescopes 
are collected independently by an elec- 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



93 



trometer-system. The position of the fiber 
of the electrometer is recorded on a ro- 
tating film. This apparatus, which is ca- 
pable of registering high-speed counting 
rates, was sent up once to the stratosphere 
for measuring the intensity of the soft com- 
ponent. Further flights to high altitudes 
are in preparation. 

Production of secondary radiation. The 
experiments of Schein, Jesse, and Wollan 
on the production of mesotrons in the 
stratosphere have been continued by M. 
Schein and M. Jona. Multiple production 
of mesotrons by non-ionizing rays could 
not be found. It therefore seems that the 
majority of the mesotrons in the strato- 
sphere are produced by ionizing rays (pro- 
tons). The angular spread of the meso- 
trons produced in the stratosphere was 
investigated and found to be much smaller 
than on Mount Evans as measured by 
Regener. This can be explained by the 
fact that close to the top of the atmosphere 
the primaries which produce the mesotrons 
have considerably higher energies (about 
io 10 electron-volts) than the average energy 
of the mesotron-producing radiation on 
Mount Evans, which is around 2 X io 9 
electron-volts. 

In a further study, the number of meso- 
trons stopped between 4 and 8 cm of lead 
has been measured as a function of alti- 
tude. These mesotrons have an energy 
of about io 8 electron-volts. The intensity- 
curve obtained shows the presence of these 
slow mesotrons in altitudes below 25 km. 
The curve has a pronounced maximum at 
a pressure of about 5 cm of mercury. To 
determine the exact position of this maxi- 
mum, further high-altitude flights must 
be made. The presence of slow mesotrons 
in altitudes below 25 km can be explained 
on the basis of the assumption made by 
Carlson and Schein that the mesotrons are 
produced with an average energy of about 



5 X io 8 electron-volts and then slowed 
down by ionization-loss in the air. There 
is thus no reason to assume, as has some- 
times been suggested, that mesotrons oc- 
cur with a life many times less than that 
of those now known. 

M. Shapiro studied the nature of the 
particles in cosmic-ray "stars" found in 
photographic emulsions. His analysis leads 
to the conclusion that 90 per cent of the 
tracks in "stars" are protons. The rest is 
probably due to alpha particles. 

Properties of mesotrons. L. Seren meas- 
ured the number of knock-on electrons in 
equilibrium with mesotrons. The meas- 
urements were carried out in a counter- 
controlled cloud-chamber. Seren found 
that the number of collision-electrons orig- 
inating from mesotrons is in good agree- 
ment with theoretical predictions. This is 
a significant verification of the laws of elec- 
trodynamics as applied to particles with 
extremely high energies. 

Personnel. The following members of 
the Physics Department of the University 
of Chicago were engaged on this work in 
July 1941 : William P. Jesse, Marcel 
Schein, Ernest O. Wollan, Donald J. 
Hughes, Ardis T. Monk, Elmer Dershem, 
Niel F. Beardsley, and Victor H. Regener. 
As guests of the laboratory, Paulus Pom- 
peia, Norman Hilberry, and Ann Hepburn 
Hilberry were active. As graduate stu- 
dents, Winston H. Bostick, Leo Seren, and 
David B. Hall have made notable contri- 
butions. The urgency of other work has 
required during the year the withdrawal 
of William P. Jesse, Ernest O. Wollan, 
Donald J. Hughes, and Ardis T. Monk, 
as well as of the guests and graduate stu- 
dents just mentioned. The addition of 
Pierre Auger and A. Rogozinski has 
greatly helped our situation. The oppor- 
tunities for important achievement in this 
field have never seemed more promising. 



94 



CARNEGIE INSTITUTION OF WASHINGTON 



BIBLIOGRAPHY 

Bostick, W. H. Cloud chamber photographs at 
14,170 feet altitude. (Abstract) Phys. Rev., 
vol. 61, p. 104 (1942). 

Cloud chamber photographs at 4310 

meters altitude. Phys. Rev., vol. 61, p. 557 
(1942)- 

Hall, D. B. Mesotron and electron energy spec- 
trum at 14,260 feet altitude from absorption 
measurements in lead. (Abstract) Phys. 
Rev., vol. 61, p. 105 (1942). 

Hughes, Donald. Cloud chamber photograph of 
a slow mesotron pair. Phys. Rev., vol. 60, 
p. 414 (1942). 

Regener, V. H. Production of penetrating par- 
ticles on Mt. Evans. (Abstract) Phys. Rev., 
vol. 61, p. 105 (1942). 

Production of penetrating particles in 

the cosmic radiation. (Abstract) Phys. Rev., 
vol. 61, p. 734 (1942). 

Schein, M., D. B. Hall, and J. Hamilton Hall. 

The variation of intensity of cosmic rays 

with zenith angle at 14,200 feet altitude. 

(Abstract) Phys. Rev., vol. 61, p. 105 (1942). 
Shapiro, M. M. A statistical study of cosmic 

ray "star" tracks in a photographic emulsion. 

(Abstract) Phys. Rev., vol. 61, p. 104 (1942). 

Frequency of proton and alpha tracks 

in cosmic ray "stars." Phys. Rev., vol. 61, 
p. 115 (1942). 

Wollan, E. O. A mesotron shower. Phys. Rev., 
vol. 60, p. 532 (1941). 

Statistical Investigations of Cosmic-Ray 
Variations 

S. E. Forbush and Isabelle Lange 

Department of Terrestrial Magnetism , 
Washington, District of Columbia 

Instruments. Operation of the Carnegie 
Institution's precision cosmic-ray meters 
was continued at the following stations: 
Cheltenham (Maryland, United States) 
Magnetic Observatory of the United States 
Coast and Geodetic Survey, meter C-i, 
A. K. Ludy and John Hershberger in 
charge; Huancayo (Peru) Magnetic Ob- 
servatory of the Department of Terrestrial 
Magnetism, Carnegie Institution of Wash- 
ington, meter C-2, P. G. Ledig in charge; 
National Astronomical Observatory of 



Mexico at Teoloyucan (D. F., Mexico), 
meter C-4, Dr. Joaquin Gallo in charge; 
Amberley Branch of the Christchurch 
(New Zealand) Magnetic Observatory of 
the Department of Scientific and Industrial 
Research, meter C-5, J. W. Beagley in 
charge; Godhavn (Greenland) Magnetic 
Observatory of the Danish Meteorological 
Institute, meter C-6, K. Thiesen and H. P. 
Barfod in charge. 

Reduction of data. Scalings and tabula- 
tions of hourly values of cosmic-ray ioniza- 
tion, bursts, and barometric pressure were 
continued for the records from Chelten- 
ham, Huancayo, and Godhavn, and at 
Christchurch (by J. W. Beagley). Owing 
to pressure of war work it has not been 
possible to maintain the complete reduc- 
tions current. 

Investigations. A further striking ex- 
ample of the magnetic-storm effect on cos- 
mic-ray intensity occurred during the mag- 
netic storm of March 1, 1942. In the 6-hour 
interval beginning with the sudden com- 
mencement of this magnetic storm, the 
cosmic-ray intensity decreased about 8 per 
cent simultaneously at Huancayo and at 
Cheltenham. Sufficient data on magnetic- 
storm effects on cosmic-ray intensity 
should soon be available for statistical in- 
vestigations which may assist in under- 
standing the mechanism involved. 

BIBLIOGRAPHY 

Lange, I., and S. E. Forbush. Note on the 
effect on cosmic-ray intensity of the magnetic 
storm of March 1, 1942. Terr. Mag., vol. 47, 
pp. 185-186 (1942). 

Report on Cosmic-Ray Work 

Victor F. Hess 
Fordham University, New Yor\, N. Y. 

Studies on latitude- and temperature- 
effect of cosmic rays aboard the "Santa 
Ana," between New Yor\ and Valparaiso. 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



95 



The registrations of cosmic-ray intensities 
with a model-C cosmic-ray meter, begun 
in September 1940, were continued until 
February 1942. Later registrations were 
not evaluated since the ship's route was 
changed and the logs were not available 
on account of the war. Twelve round trips 
had been completed in February 1942; 
the data on the first three trips were in- 
complete, and therefore only the observa- 
tions during trips 4 to 12 are being used 
for publication. A preliminary report was 
given by Rev. Edward B. Berry, S. J., 
at the meeting of the American Physical 
Society in December 1941. (A complete 
report will be published in the Journal of 
Terrestrial Magnetism and Atmospheric 
Electricity, September 1942.) 

From the correlation of cosmic-ray inten- 
sities, corrected for barometric readings, 
with temperature at sea-level, the tempera- 
ture-coefficients for all geomagnetic lati- 
tudes on the route from New York to 
Chile were computed. The smallest values 
of these temperature-coefficients were 
found to be grouped symmetrically around 
the geographic equator. The latitude-effect 
curve, corrected for effect of temperature, 
was obtained and is generally in agree- 
ment with curves in the Pacific, as found 
by Compton and Turner and by Gill. Cer- 
tain small deviations can be explained by 
the longitude-effect of the cosmic radiation. 

The influence of the aurora and of the 
magnetic disturbance of September 18, 
1941 was studied with the model-C meter 
and with counter-telescopes, and a report 
on these phenomena was published. 

Studies on mesotron-disintegration and 
temperature-effect of cosmic radiation. A 
dual telescope for continuous registration 
of the mesotron-component of cosmic ra- 
diation, devised and constructed at the 
Bartol Research Foundation by Dr. W. F. 
G. Swann in collaboration with Dr. Hess, 
has been in operation at Fordham Uni- 



versity since March 1941. The unit con- 
sists of 108 Geiger-Miiller counting-tubes 
in six trays mounted in a vertical counter- 
train; alternate trays are so connected for 
coincidence-counting that in reality there 
are two independent but interposed tele- 
scopes of three trays each, with 22 cm of 
lead between the trays and additional 
heavy screens for exclusion of side showers. 
Thus mesotrons coming in from the verti- 
cal direction are actuating both telescopes 
and are recorded by photographing the 
dials of two special recorders automatically 
every 2 hours. Reliability of operation is 
indicated by the constancy, within the 
natural fluctuations, of the counting-ratio 
between the upper and the lower telescope. 
Work with this telescope was begun in col- 
laboration with F. A. Benedetto, S. J., and 
G. O. Altmann. 

The mesotron-intensities obtained were 
compiled and reduced for 12- and 24-hour 
periods, and these values, after correction 
for the barometric effect, were correlated 
with temperatures at ground and at var- 
ious levels of the daily atmosphere up to 
about 16 km, as supplied from the sound- 
ing-balloon flights at Lakehurst, New 
Jersey. 

In collaboration with F. A. Benedetto it 
was shown that there is a continuously de- 
creasing temperature -coefficient as one cor- 
relates mesotron-intensities at ground with 
temperatures at increasingly higher levels. 
This indicates that air-mass is more funda- 
mental in these investigations, and that 
when average temperatures are taken by 
the spatial-average method, the tempera- 
tures at the higher levels have undue in- 
fluence. With the method used by Bene- 
detto and Hess, averages of temperature 
for various fractions of the atmosphere can 
be taken which are determined only by 
the mass of air in each fraction ("mass- 
temperature") . It was shown that then the 
temperature-coefficient is almost constant 



9 6 



CARNEGIE INSTITUTION OF WASHINGTON 



for all fractions of the daily atmosphere 
up to four-fifths of the total air-mass. This 
corroborates the view that the so-called 
temperature-effect of cosmic rays is pri- 
marily an effect of atmospheric mass-dis- 
tribution variations. 

In collaboration with F. A. Benedetto 
and G. O. Altmann, the changes of meso- 
tron-intensity with change in the average 
height of the center of gravity of the at- 
mosphere were studied. From the co- 
efficient of displacement derived therefrom, 
the mean range of life and mean lifetime 
of the mesotrons at sea-level were calcu- 
lated. 

A complete description of the dual tele- 
scope is given in the March 1942 issue of 
Physical Review. In this paper, which 
gives further results, it is shown that the 
temperature-coefficient of cosmic radiation 
varies as dz/dT (change of height of an 
atmospheric layer with temperature), 
when increasing fractions of the atmos- 
phere, up to four-fifths of the total atmos- 
phere, are taken. The assumption that 
mesotrons are produced throughout the 
atmosphere according to the distribution of 
the air-mass leads to a mean lifetime of the 
mesotrons at rest rather smaller than that 
obtained by other methods. These meas- 
urements are being continued by F. A. 
Benedetto, S. J. 

Gish-Hess ionization-meter. In a theo- 
retical study it is shown that, if one com- 
putes the ionization produced by gamma 
rays from radioactive substances in rocks 
and soil from figures given recently as aver- 
age values for representative classes of 
rocks, the expected ionization turns out 
considerably smaller than that actually ob- 
served by placing ionization-vessels over 
land and over water. Two methods were 
developed theoretically which make it pos- 
sible to determine simultaneously the re- 
sidual ionization, the effect of cosmic radi- 
ation, and the effect of gamma rays from 



the soil or from rocks (local radiation), 
and to separate these components of the 
total ionization. 

Comparison of ionizations determined 
by one of these methods with values com- 
puted from given figures of radioactive 
material in well defined rocks is planned, 
and the experimental equipment for this 
work was constructed by the Department 
of Terrestrial Magnetism of the Carnegie 
Institution of Washington. The author 
acknowledges the valuable aid of the Di- 
rector, the Assistant Director, and their 
associates in the Department during this 
work. 

BIBLIOGRAPHY 

Benedetto, F. A., G. O. Altmann, and V. F. 
Hess. Mesotron studies with dual telescope. 
Phys. Rev., vol. 61, pp. 266-269 (1942). 

Berry, Edward B. Cosmic-ray measurements be- 
tween New York and Valparaiso. (Abstract) 
Bull. Amer. Phys. Soc, vol. 16, p. 15 (1941). 

Hess, V. F. Radioactivity of rocks and ionization- 
balance of the atmosphere. Terr. Mag., vol. 
46, pp. 411-415 (1941)- 

and G. O. Altmann. Effects of changes 

in height of air mass on mesotron intensity. 
(Abstract) Bull. Amer. Phys. Soc, vol. 16, 
p. 151 (1941). 

and F. A. Benedetto. Mesotron varia- 
tion with upper air temperatures. Phys. Rev., 
vol. 60, pp. 610-61 1 (1941). 

and Edward B. Berry. Cosmic rays and 

the magnetic disturbance of September 18, 
1941. Phys. Rev., vol. 60, p. 746 (1941). 

Studies of Cosmic Rays 

Thomas H. Johnson 

Bartol Research Foundation of the Franklin 
Institute, Swarthmore, Pennsylvania 

During the year ending June 30, 1942, 
Dr. Johnson and his associates have con- 
tinued investigations of the composition 
of the cosmic radiation in the lower atmos- 
phere and of the processes of interaction of 
cosmic rays with matter. All the experi- 
mental studies during this period have 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



97 



been made with a large Wilson cloud- 
chamber, fitted with various lead absorbing 
screens and arrangements of coincidence- 
counters. With this instrument 42,000 pho- 
tographs have been taken and analyzed. 
The analysis of a part of these was re- 
ported last year. Although the analysis is 
now completed, the final conclusions can- 
not yet be announced. 

Out of all the 42,000 photographs taken 
with the large chamber, only one showed 
a mesotron reaching the end of its range 
within the gas in the chamber. From 
measurements of the curvature and range 
of this particle, its rest-mass has been esti- 
mated as 75 times that of an electron. The 
particle was negatively charged and gave 
no indication of having disintegrated. It 
is interesting to note that the three or 
four disintegrations of mesotrons which 
have been observed in cloud-chambers 
have all been of positive rays. The present 
photograph represents the third negative 
particle observed to have stopped in the 
gas of a Wilson chamber. 

Much attention during the past year has 
been devoted to the construction of a large 
high-pressure Wilson chamber of novel 
design. This chamber has been operated 
with controlled expansions at a pressure 
of 32,000 pounds per square inch. Good 
photographs of cosmic rays have been 
made with the chamber operating at a 
pressure of 400 pounds per square inch, 
and visible tracks accompanied by undesir- 
able fog have been observed at 800 pounds 
per square inch. Now that the problems 
associated with the control of the expan- 
sions are solved, it is hoped that other 
troubles may soon clear away. This cham- 
ber will give a gaseous stopping power 
equivalent to 1 cm of lead, and it is an- 
ticipated that many examples of tracks 
will be found showing some of the rarer 
but highly interesting events of cosmic- 
ray absorption. 



Personnel. Because of other require- 
ments on Dr. Johnson's time, the work 
during this period has fallen almost wholly 
upon Messrs. R. P. Shutt and Sergio de 
Benedetti. They have had the assistance, 
from January 1 to June 30, 1942, of Martin 
H. Hornstine. 

BIBLIOGRAPHY 

Johnson, T. H., and R. P. Shutt. Cloud cham- 
ber track of a mesotron stopped by gas. 
Phys. Rev., vol. 61, pp. 380-381 (1942). 

Pomerantz, M. A., and T. H. Johnson. The 
relative stopping powers of carbon and lead 
for slow mesons. (Abstract) Jour. Franklin 
Inst., vol. 232, p. 185 (1941). 

Cosmic-Ray Investigations 
S. A. Korff 

New Yor\ University, New Yor\, N. Y., and 

Bartol Research Foundation of the Franklin 

Institute, Swarthmore, Pennsylvania 

The cosmic-ray investigations carried 
out from July 1, 1941 to June 30, 1942, with 
the aid of funds made available through 
the Carnegie Institution of Washington, 
are set forth below. 

Cooperation with United States Antarc- 
tic Service. The cosmic-ray data obtained 
on the United States Antarctic Expedition 
were analyzed. The observational pro- 
gram was divided into several sections. 
The first of these was the long-term study 
of the cosmic-ray intensity in Little Amer- 
ica through the recordings of two meters 
during most of the antarctic winter of 1940. 
The resulting corrected daily means of 
cosmic-ray intensity were computed. 
These showed a decrease of intensity dur- 
ing only one of five magnetic storms re- 
corded. This is noteworthy in view of 
the better correlation shown between mag- 
netic storms and cosmic-ray intensity in 
temperate latitudes, but is understandable 
because of the unique character of the geo- 
magnetic field in high latitudes. From 



9 8 



CARNEGIE INSTITUTION OF WASHINGTON 



the compilations for an external tempera- 
ture-coefficient it was found that the fluc- 
tuations in the cosmic-ray intensity cor- 
related somewhat better with the changes 
in the temperature of the upper atmos- 
phere than with those at sea-level. This 
condition was due to the large inversions 
of temperature occurring near the surface 
of the polar ice during the antarctic win- 
ter, as a result of which the temperatures 
at the surface in the Antarctic are not al- 
ways indicative of the mean conditions in 
the air-mass overhead. This observation 
accords well with the view that the pene- 
trating particles in the cosmic-ray radia- 
tion are produced at levels in the upper 
atmosphere, the variations in which levels 
are determined by the mean air-mass tem- 
peratures. Further analysis of these data 
is still in progress. 

On the return trip from Antarctica a 
meter was operated continuously on board 
ship. An excellent run through far south- 
ern latitudes was obtained, comparable 
with that obtained on the voyage to Little 
America the previous year. It was found 
that the cosmic-ray intensity continued to 
increase slowly with increasing southerly 
latitude south of the familiar knee in the 
curve, but that this increase could be at- 
tributed to a decrease in the average ex- 
ternal temperature. When an external 
temperature-coefficient was applied to the 
data, the curve at all latitudes south of 
New Zealand was sensibly flat. The fact 
that it was possible to use an external 
temperature-coefficient indicates that the 
air-mass conditions over the ocean in this 
region are fairly uniform and not char- 
acterized by such large temperature-inver- 
sions as were found over the ice. 

Study of nuclear dissociations produced 
by cosmic rays. The processes by which 
cosmic rays produce neutrons and protons 
through nuclear dissociations were studied 
at several elevations. The neutrons were 



investigated by using a neutron-counter 
together with cadmium absorbers and a 
shield of water, which permitted an evalu- 
ation of the number of neutrons in the 
thermal energy-range to be made. The 
protons produced by the radiation were 
studied with the aid of a methane counter. 
These experiments permitted the numbers 
and rates of production of each to be de- 
termined. These rates could then be com- 
pared with the other cosmic-ray variables 
at each altitude. The rates of production 
of neutrons and protons were found to in- 
crease with altitude faster than the total 
intensity of cosmic radiation and at about 
the same rate as the soft (electronic) com- 
ponent. Although the total number of 
neutrons appeared to be considerably 
greater than the number of protons, when 
account was taken of the much greater 
range of the neutrons and of the lower 
efficiency of the detection of neutrons, it 
was found that neutrons and protons are 
produced by the cosmic radiation at 
roughly the same rate. In this connection 
it must be recalled that protons and neu- 
trons are present in approximately equal 
numbers in the nuclei of the light ele- 
ments studied, that they are bound to 
these nuclei by energies which though 
slightly different are of the same orders of 
magnitude, and further that the energy of 
the entity producing the disintegration is 
large as compared with these binding en- 
ergies. Thus cosmic rays are providing a 
new tool for the investigation of nuclear 
structure. 

The observations led to the hypothesis 
of a possible connection between the proc- 
ess of production of neutrons and protons 
and cosmic-ray showers, namely, that the 
dissociation producing these particles may 
be produced by the photons which are 
present in abundance in the soft compo- 
nent. An experiment was designed to 
test this hypothesis. The apparatus was 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



99 



arranged to count those discharges of neu- 
tron-counters and of cosmic-ray-shower 
counters which were coincident in time. 
The test was made with and without 
the cadmium shield which absorbs slow 
neutrons. This experiment gave a positive 
result indicating that a large percentage of 
the neutrons were associated with cosmic- 
ray showers, thus lending support to the 
suggestion that they are in all probability 
produced by the photons present in the 
radiation. These experiments were per- 
formed at several elevations, namely, at 
Swarthmore, in Denver, and at the 
Cosmic-Ray Laboratory on the summit of 
Mount Evans. 

Personnel. The reduction of the cosmic- 
ray data obtained in the Antarctic was 
done by Dana K. Bailey. The records were 
measured under his supervision by Ernest 
K. Smith. Correlation-coefficients and de- 
pendences on pressure and temperature 
were computed by Robert A. Taylor. Eric 
T. Clarke assisted with the nuclear-dis- 
integration experiments made on Mount 
Evans. It is a pleasure to acknowledge 
the cooperation of these and other col- 
laborators. 

BIBLIOGRAPHY 

Clarke, E. T., and S. A. Korff. The radiosonde: 
the stratosphere laboratory. Jour. Franklin 
Inst., vol. 232, pp. 217-238, 339-355 ( I 94 1 )- 

Korff, S. A. Neutrons produced by the cosmic 
radiation at 14,170 feet altitude. (Abstract) 
Phys. Rev., vol. 61, p. 393 (i94 2 )- 

Report on cosmic-ray results (United 

States Antarctic Expedition of 1939-41). 
(Abstract) Science, vol. 94, pp. 549"55° 
(1941). 

Cosmic ray observations on the U. S. 

Antarctic Expedition. Sky and Telescope, 
vol. 1, pp. 14-16 (1942). 

Nuclear particles in the cosmic radiation. 

(Abstract) Jour. Franklin Inst., vol. 232, 

PP- 383-384 (i94i)- 

The operation of proportional counters. 

Jour. Franklin Inst., vol. 232, pp. 73-75 
(1941); Rev. Modern Phys., vol. 14, pp. i-n 
(1942). 



— Cosmic-ray investigations in connection 
with the United States Antarctic Expedition. 
Year Book, Amer. Philos. Soc, 1941, pp. 
102-103 (1942). 

— The production of neutrons by the cos- 
mic radiation. Proc. Amer. Philos. Soc, vol. 
84, pp. 589-603 (1941); (abstract) Jour. 
Franklin Inst., vol. 232, p. 497 (1941). 

— and E. T. Clarke. The production of 
neutrons and protons by the cosmic radia- 
tion at 14,125 feet. Phys. Rev., vol. 6r, pp. 
422-427 (1942). 

— W. D. B. Spatz, and N. Hilberry. 



Temperature coefficient in self-quenching 
counters. Rev. Sci. Instr., vol. 13, pp. 127-128 
(1942). 

Studies of Cosmic Rays 

Robert A. Millikan 

California Institute of Technology, 
Pasadena, California 

During the year July 1, 1941 to June 30, 
1942, the research time and energies of the 
whole physics staff at the California In- 
stitute of Technology were devoted almost 
entirely to war problems. Nevertheless, so 
important cosmic-ray results have seemed 
to be in process of appearing from the pro- 
jected program of experiments that some 
time has been stolen by a few of the work- 
ers in that field to push forward in three 
most significant and promising directions, 
namely: (1) in the testing in new lati- 
tudes by Millikan, Neher, and Pickering 
of their hypothesis as to the origin of 
cosmic-ray energies; (2) in the completion 
by Anderson and his students of their 
60-cm high-resolution cloud-chamber for 
the more accurate study of the properties 
of mesotrons and the beginning of cloud- 
track measurements with it; and (3) in 
the improvement by Neher, Pickering, and 
Stever of cosmic-ray Geiger counters and 
studies of the mechanism of such counters. 

Tests by Robert A. Millikan, H. Victor 
Neher, and William H. Pickering, in Mex- 
ico and the United States, of the predic- 
tions of their hypothesis, (a) Tests in 



100 



CARNEGIE INSTITUTION OF WASHINGTON 



Mexico : These authors had predicted that 
since their hypothetical silicon-annihila- 
tion rays should have enough energy (13.2 
billion electron-volts) to get through the 
earth's magnetic field at the geomagnetic 
equator in Peru, though not in India, there 
should be found at sea-level in the Amer- 
icas a very long plateau of uniform, verti- 
cal cosmic-ray intensities extending north 
from Peru clear up to about the magnetic 
latitude of Victoria, Mexico (magnetic lati- 
tude, = 32?8 north). There the strong 
band due to the annihilation of the oxygen 
atom (computed energy 7.5 billion elec- 
tron-volts) should first begin to be able 
to break vertically through the earth's mag- 
netic field. 

To test this quantitative prediction, the 
observers fitted out a truck as a radio lab- 
oratory and in December 1941 drove it as 
far south in Mexico as they could, namely, 
to Acapulco. There they made careful 
measurements on the vertically incoming 
rays both at sea-level and at all altitudes 
up to near the top of the atmosphere. 

Both of the foregoing types of measure- 
ment (those taken at sea-level and those 
taken by integrating, with the aid of in- 
struments taken up in balloon flights to 
very great heights, all the incoming cosmic- 
ray energy at all altitudes) revealed, as 
predicted, no increase whatever between 
the latitude of Acapulco (0 = 25? 8 north) 
and that of Valles, 375 miles farther 
north. The upper-air measurements actu- 
ally showed at Valles a small decrease, 
which was, however, inside the limits of 
instrumental uncertainties. 

But in going from Valles to Victoria 
(0 = 32?8 north), a distance of but 112 
miles, there was found a sudden, unam- 
biguous rise in both the sea-level vertical 
intensity and the total integrated vertically 
incoming cosmic-ray energy. These find- 
ings were, then, in excellent agreement 
with the predictions of the theory as to the 



approximate latitude at which the cosmic 
rays due to the annihilation of oxygen 
atoms should first begin to appear as the 
observer travels north in the Americas 
from the magnetic equator. 

A further check on the theory was found 
in the following situation. If there were 
any sort of continuous distribution of the 
incoming cosmic rays with incident en- 
ergy, then, since the earth's magnetic field 
is stronger in India than in Mexico, the in- 
tensity of the vertically incoming rays 
should be greater in Acapulco, Mexico 
(0 = 25?8 north) than in Peshawar, India 
(<D = 25° north). But the hypothesis de- 
nied the possibility of this result. Five 
different flights were made in Acapulco 
to test this point. The best of these flights 
gave practically the same vertical cosmic- 
ray intensity as that found in the observa- 
tions taken in Peshawar in 1940. The 
mean in Acapulco was slightly lower than 
in Peshawar, though not enough so to be 
outside the limits of instrumental un- 
certainty. 

(b) Tests in the United States: Again 
in driving the truck-laboratory from the 
latitude of Victoria, Mexico (0 = 32?8 
north) to that of San Antonio, Texas 
(0 = 38?4 north) and Pasadena, Cali- 
fornia (0 = 40? 7 north), where the verti- 
cal sea-level intensities were found to be 
the same, the hypothesis required that at 
the two last latitudes the annihilation- 
rays both of oxygen atoms and of nitrogen 
atoms should be added to the annihilation- 
rays of silicon atoms, as measured in 
Peshawar in India in 1940 and in both 
Acapulco and Valles in December 1941. 
The observations both of sea-level intensity 
and of integrated energy revealed the pre- 
dicted large increase between these lati- 
tudes (over 30 per cent). 

The observers also made in March 1942 
preliminary and less dependable measure- 
ments of the changes in integrated energy 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



101 



in going from Pasadena, California (0 = 
40?7 north) to St. George, Utah ($ = 45° 
north). Their single flight at St. George 
showed an increase of 18 per cent over 
that at Pasadena. This increase they at- 
tribute to the entrance between these lati- 
tudes of the carbon-atom-annihilation rays. 

In going from St. George to Pocatello, 
Idaho (0 = 51° north), a change of 6° 
in contrast with the change of 4 from 
Pasadena to St. George, they found in their 
only measured flight no increase — a result 
required by their hypothesis, since there 
are no abundant atoms of atomic weight 
between that of carbon and that of helium. 

(c) Discovery of large variability of 
helium-annihilation rays: Within the year 
(in August and September 1941) these 
same observers made a series of accurate 
measurements of total incoming cosmic- 
ray energy as measured by electroscopes, 
rather than by vertical counters, sent to 
close to the top of the atmosphere at 
Bismarck, North Dakota (0 = 56?7 
north), Omaha, Nebraska (0 = 5i?3 
north), Oklahoma City, Oklahoma (0 = 
45 north), Fort Worth, Texas (0 = 
41 ?6 north), and San Antonio, Texas 
(0 = 38?4 north). These accurate meas- 
urements brought to light the notable 
fact that whereas the total incoming en- 
ergy at San Antonio was the same as that 
measured there in 1935, the helium-an- 
nihilation rays coming in at Bismarck, 
measured within a week of the measure- 
ments at San Antonio, showed at the top 
an increase of at least 30 per cent over 
measurements of the same sort made there 
in 1938. The soft rays due to helium are, 
then, very much more variable than are 
the hard rays due to the heavier and very 
much less abundant atoms. Whether this 
variability in the softest component of the 
incoming rays is due to changes in the 
magnetic field of the earth or of the sun or 



represents a more fundamental variability 
in the rate at which helium atoms are be- 
ing transformed in outer space into cosmic 
rays is yet to be determined. 

Wor\ of Carl D. Anderson, Leon Katz, 
and R. V. Adams on a high-resolution 
cloud-chamber for the accurate determina- 
tion of the properties of mesotrons. The 
large magnet-cloud-chamber apparatus at 
the California Institute has been in opera- 
tion during the year July 1941 to June 1942. 
In all only about 1000 photographs were 
taken, as most of the time was spent in 
improving the operation of the apparatus, 
principally with regard to decreasing the 
small distortions of the tracks due to mo- 
tions of the gas. These motions are the 
most important factor in limiting the ac- 
curacy of the energy-measurements. Sev- 
eral different designs of the moving dia- 
phragm have been tested, the timing of 
the illumination has been improved, 
and better temperature-control has been 
achieved. At present it is possible to meas- 
ure energies in good tracks up to 20 
billion electron-volts with fair precision. 
A system for measuring the tracks by re- 
projecting the images and thus eliminat- 
ing all lens distortion has been completed. 

Improvement in cosmic-ray Geiger coun- 
ters and studies of the mechanism of such 
counters, by H. Victor Neher, William H. 
Pickering, and H. G. Stever. As an off- 
shoot of the development of high-altitude 
Geiger-counter observations, these work- 
ers made fundamental studies in the op- 
eration of Geiger counters. These led di- 
rectly to the development of a new type 
of counter, in which the central wire is 
provided with glass beads which isolate 
the counter into sections, and which there- 
by not only permits coincidence-measure- 
ments with a single counter, but illumi- 
nates from a new angle the whole theory 
of counter-action. 



102 



CARNEGIE INSTITUTION OF WASHINGTON 



BIBLIOGRAPHY 

Millikan, Robert A., H. Victor Neher, and 
William H. Pickering. A hypothesis as to 
the origin of cosmic rays and its experimental 
testing in India and elsewhere. Phys. Rev., 
vol. 61, pp. 397-407 (1942). 

Neher, H. V., and W. H. Pickering. Results 
of a high altitude cosmic-ray survey near 
the magnetic equator. Phys. Rev., vol. 61, 
pp. 407-413 (1942). 

A cosmic-ray radio sonde. Rev. 

Sci. Instr., vol. 13, pp. 143-147 (1942). 

Stever, H. G. The discharge mechanism of 
fast G-M counters from the deadtime experi- 
ment. Phys. Rev., vol. 61, pp. 38-52 (1942). 

Mass of the Mesotron 

Wilson M. Powell 

Kenyon College, Gambler, Ohio, and University 
of California, Berkeley, California 

On July 1, 1941, an expedition to the 
summit of Mount Evans (14,125 feet) 
was already under way. This work and 
its development had been made possible 
through the support of the Rumford Fund 
for the Study of Radiation of the Ameri- 
can Academy of Arts and Sciences, the 
Penrose Fund of the American Philosophi- 
cal Society, the Fund for Astrophysical 
Research, and the John Simon Guggen- 
heim Memorial Foundation. Preliminary 
reports on six months' examination of over 
20,000 photographs of cosmic rays passing 
through a large Wilson cloud-chamber ob- 
tained on that expedition were published 
in Physical Review (see bibliography) ; a 
complete paper on the results is in prepara- 
tion. Many valuable suggestions in inter- 
preting the results were given by Professor 
J. R. Oppenheimer. 



As a result of this work, and with the 
continued financial support of the organi- 
zations above mentioned and of the Car- 
negie Institution of Washington, plans 
were made to measure the mass of the 
mesotron with a cloud-chamber and a 
magnetic field. A new cloud-chamber was 
made following techniques developed by 
Professor R. B. Brode and his students 
at the University of California, and utiliz- 
ing some apparatus obtained by the De- 
partment of Physics of the University. The 
new cloud-chamber is used with a large 
pair of Helmholtz coils. These coils are 
supplied by storage batteries with a large 
current at the moment of expansion and 
photography of the cloud-chamber. Statis- 
tical treatment of the data obtained 
through the earlier random photographs at 
the summit of Mount Evans indicates that 
a large number of slow mesotrons may be 
observed whose ionization is measurably 
denser than that of a high-energy electron. 

Dr. Carl E. Nielsen, of the University 
of California, assisted in this research and 
in preparation of apparatus, and after the 
transfer of Dr. Powell to war-research 
activities, on June 10, 1942, took full charge 
of the investigation. After tests at Berke- 
ley, which showed that the whole appa- 
ratus functioned as expected, he reached 
the summit of Mount Evans with practi- 
cally all the equipment, mounted in a 
trailer. 

BIBLIOGRAPHY 

Powell, Wilson M. Production of mesotrons 
by ionizing radiation. Phys. Rev., vol. 60, 
pp. 413-414 (1941)- 

Stars and slow protons at 14,125 feet. 

Phys. Rev., vol. 61, pp. 670-671 (1942). 



California Institute of Technology, Pasadena, California. Cooperative researches 
at the Seismological Laboratory. (For previous reports see Year Books Nos. 37 
to 40.) 



One part of the research program at the 
Seismological Laboratory at Pasadena is 
concerned with local earthquakes, that is, 



those originating in southern California 
and adjacent territory. The purposes of 
this part of the program include the de- 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



103 



termination of the following: the seis- 
micity of southern California and of its 
different parts; the relations of earthquakes 
to the faults known in the region; the 
origin and nature of shocks not originating 
on the more important faults but within 
the great crustal blocks; the depths of the 
origins of shocks; the accelerations, periods, 
and other elements in local earthquakes, 
desired by engineers as data for com- 
puting strengths of structures to be built 
in the region; and the nature of the forces 
causing the mountain making and the 
earthquakes in this part of the state. An- 
other part of the activity of the Labora- 
tory deals with broader geophysical and 
tectonic problems, for which the data from 
both local and distant earthquakes are 
essential. Among such problems are the 
thickness and the nature of the earth's 
so-called crust in the different parts of 
southern California, the thickness of the 
crust where deformed by past mountain 
making, and the quantitative relations of 
such elements of earthquakes as their mag- 
nitudes, intensities, and accelerations. 

The largest amount of data obtainable, 
in the form of precise seismographic rec- 
ords, is none too extensive for the success- 
ful prosecution of the researches on the 
problems mentioned above. For this rea- 
son the instruments at the Pasadena labora- 
tory and the seven outlying stations in 
southern California are kept in continuous 
operation. After many years' effort, they 
now write very accurate records and per- 
mit time determinations of the phases of 
earthquakes to a small fraction of a second. 
The Laboratory's records now, together 
with those obtained by the University of 
California in central California, those made 
by the U. S. Bureau of Reclamation at 
Lake Mead, and those written by the 
U. S. Coast and Geodetic Survey at Tucson 
and on their strong motion instruments 
at numerous localities in the Southwest, 



give a better set of data on every earth- 
quake occurring in the Southwest than has 
ever been available before. The system- 
atic registration of shocks in this region 
can continue for a long time to come be- 
fore the effort and expense will begin to 
yield decreasing returns both on the prac- 
tical and on the theoretical side of seis- 
mology and geophysics. 

A full program of registration has been 
continued during the year at the Pasa- 
dena laboratory and at the seven outlying 
stations, including Palomar. 

Though equipment has been maintained 
and some improvements have been made 
at some of the stations, instrument design 
and construction are in abeyance for the 
duration of the war. Dr. Benioff and his 
mechanical staff are engaged on govern- 
ment research and construction, utilizing 
the shop facilities of the Laboratory. 

Mr. Robert E. Rogers accepted a com- 
mission in the U. S. Navy and was granted 
a leave of absence to begin July 15, 1942. 
Miss Patricia Hawkins begins service as 
an assistant in the measurement of rec- 
ords on July 1, 1942. Miss Catharine Mc- 
Collum will take charge of the photo- 
graphic and related work in the Labora- 
tory on September 2, 1942. 

Crustal structure. The earth is made of 
concentric shells of different types of rock 
material. The outermost shell, or crust, 
consists of an upper or granitic layer, 
which forms the continents, and deeper 
layers of comparable thickness made of 
basic igneous rock. The average thick- 
ness of the crust is about 35 or 40 km. 
The detailed nature of this crust has 
been under vigorous investigation at the 
Seismological Laboratory during the past 
year. Answers were desired to such ques- 
tions as, What is the thickness of the two 
parts of the crust under southern Cali- 
fornia, and under mountains? Do moun- 
tains have "roots," and what happens when 



104 



CARNEGIE INSTITUTION OF WASHINGTON 



mountains are formed by telescoping of 
the crust, with reference to the thickening 
of the granitic plate or upper part of the 
crust and with reference to the basaltic 
or lower part? Do the lower surfaces of 
these layers bulge downward, each into 
the heavier layer next below, in order to 
support the upward bulge of the granitic 
layer which we recognize on the surface 
as a mountain range ? 

The investigation of the foregoing and 
related questions during the current year 
has yielded extensive results, partially em- 
bodied in three papers already in course 
of publication and in other manuscripts 
in preparation. Two of these papers, by 
Dr. Beno Gutenberg, are "Earthquakes 
and structure in southern California" and 
"Seismological evidence for roots of moun- 
tains." 

Some of the important new conclusions, 
with the evidence therefor, brought out in 
these two papers are as follows: The 
granitic layer in southern California is 
about 1 8 km. thick, and the basaltic layers 
beneath it, forming the lower part of the 
crust, are about 22 km. thick, giving a total 
thickness of about 40 km. for the crust 
in this region. In southern California both 
the thickness of the granitic layer and the 
total thickness of the crust are consider- 
ably less than the average thickness under 
Europe, and it appears that the basic layers 
forming the lower part of the crust are of 
somewhat different composition from those 
under Europe. All the earthquakes in 
southern California apparently originate 
near the base of the granitic layer, that is, 
at a depth of about 18 km. Under the 
Sierra Nevada the total thickness of the 
crust is considerably greater than in other 
parts of southern California, being about 
60 km., but, surprisingly enough, the gra- 
nitic layer is no thicker than in surround- 
ing areas. The basaltic layers forming the 
lower part of the crust have thickened 



from about 22 to about 42 km. This thick- 
ening of only the lower layers of the crust 
under the Sierra Nevada is in marked con- 
trast with conditions in the Alps, where 
the main thickening occurred in the gra- 
nitic or uppermost layer of the crust. In 
the Alps the total thickness of the crust 
is also about 60 km., but the granitic layer 
was thickened to about 40 km. Outside 
the Alps, in Yugoslavia, the granitic layer, 
below about 4 km. of sediments, is about 
13 km. thick, and the underlying basaltic 
layers about 25 km., giving a total of about 
42 km. In New Zealand the granitic layer 
is only about 10 km. thick, and the basaltic 
layers about 20 km., so that the total crustal 
thickness is only about 30 km. 

It was possible also to obtain some data 
on the horizontal extent of the Sierran root 
or thickened part of the crust. It does not 
extend much east of the east base of the 
present upfaulted range, and it does not 
extend westward beneath the San Joaquin 
Valley. It is best developed under the 
highest part of the range, and does not 
extend southward under the Tehachapi 
Mountains, which are sometimes consid- 
ered to be the southern part of the range. 

In the Alps the mountain making, fold- 
ing, and faulting occurred after the great 
granitic batholiths were emplaced; in the 
Sierra Nevada probably the reverse is true 
for the great Jurassic mountain making. 
The question whether this explains why 
the granitic layer is greatly thickened un- 
der the Alps but not under the Sierras 
should be further investigated. 

Some progress has also been made in 
determining why waves arriving at a given 
seismographic station arrive "too early" or 
"too late." These differences in travel time 
appear to be due to two causes: differ- 
ences in paths through the deeper layers, 
which vary in thickness, and differences 
in the other rocks near the station through 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



105 



which the sedimentary waves pass in the 
last part of their paths. 

It has also been found that whereas all 
the larger shocks occur on the more im- 
portant faults, many of the minor shocks 
occur on minor faults within the major 
fault blocks. This probably means that 
the shearing forces involved in mountain 
making are in part relieved by slips on the 
major faults and in part by internal defor- 
mation of the major fault blocks into 
which the region being deformed has been 
cut by the major faults. If this assumption 
is correct, this is a very important and 
fundamental fact in tectonics or structural 
geology. 

In the course of the investigations on the 
above problems other results of very fun- 
damental nature were obtained. These are 
being published in a joint paper by Dr. 
Beno Gutenberg and Dr. Charles F. Rich- 
ter, entitled "Earthquake magnitude, in- 
tensity, energy, and acceleration," to be is- 
sued in the July 1942 number of the 
Bulletin of the Seismological Society of 
America. This paper sets forth the rela- 
tions of the important elements in earth- 
quakes: the magnitude, which may be 
said to be measured by the size of the 
area shaken; the intensity or vigor of the 
shaking; the total energy released in the 
earthquake; and the maximum accelera- 
tions in the shock. Equations for relating 
quantitatively all these elements in an 
earthquake are developed for the first time. 

Conspectus of seismologic stations. In 
the study of past earthquakes it is impor- 
tant to know what seismological stations 
were in existence at different times. Dur- 
ing the year Mr. H. O. Wood completed 
and published "A chronologic conspectus 
of seismologic stations," containing data 
for more than 800 stations which have been 
in operation for longer or shorter periods 
in different parts of the world. 

Southern California earthquakes. A 



number of important earthquakes occurred 
in southern California during the year. 
Most of them provided valuable additional 
data for Gutenberg's study of travel times 
and structures. 

On September 14, 1941, the central Sierra 
Nevada region was shaken by a group of 
shocks, the largest of which was of magni- 
tude 6. Many rock slides, some of which 
were large, were started in the range. Gu- 
tenberg determined an epicenter on Owens 
River in Long Valley. Aftershocks were 
very numerous; a large one (magnitude 
5.5) occurred as late as December 30. 

On September 5 a shock of magnitude 5 
occurred on or close to the San Andreas 
Fault in Cuddy Valley. Gutenberg's study 
shows that earlier shocks in the same 
region certainly originated north of this 
one, so that there must be activity north 
of the visible rift. 

On October 22, a shock of magnitude 5, 
originating on the Inglewood fault zone, 
caused some damage at Gardena. An off- 
set occurred on a subsurface fault in the 
near-by Dominguez Hill oil field. The 
seismological evidence shows that the point 
of initial rupture in the earthquake was 
at the usual depth (about 15 to 18 km.), 
and not under the fracture in question; the 
displacement on this fracture must be con- 
sidered as having been triggered by the 
main earthquake. The secondary earth- 
quake source thus produced seems to have 
added to the local intensity in the immedi- 
ately surrounding area. 

On November 14 a larger shock (magni- 
tude 5.5) originated farther to the south- 
west; this shock produced no further ef- 
fects in the Dominguez field, but caused 
extensive damage at Torrance and Gar- 
dena. 

On February 1, 1942, there was a long 
series of minor shocks (magnitudes up 
to 4.5) in the Lucerne Valley area north of 
the San Bernardino Mountains. 



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CARNEGIE INSTITUTION OF WASHINGTON 



On March 5 a shock of magnitude 5 
originated still farther east, in the Pinto 
Mountains. Exact study of a shock so far 
east might have provided much valuable 
information on the structures transitional 
between those of the Coast Ranges and 
of the Colorado Plateau; but Gutenberg 
found that the comparatively large dis- 
tance from all the more sensitive stations, 
and the generally unfavorable location, ren- 
ders any conclusions uncertain. The later 
installation of more sensitive instruments 
in the Lake Mead area may make it pos- 
sible to carry out complete investigations 
on future shocks in this interesting transi- 
tional region. 

Of the many distant shocks recorded, at 
least fifteen were of magnitude 7 or over 
(major earthquakes). The great Atlantic 
shock of November 25, 1941 approached 
magnitude 8.5, and thus may have been the 
largest earthquake since 1922. At Pasa- 
dena the surface waves were recorded 
with amplitudes up to 2.5 mm. (actual dis- 
placement of the ground). 

Research on sound waves. Research was 
continued on the propagation of waves in 
the atmosphere, applying the laws of elas- 
tic waves used in seismology and utilizing 
equipment specially constructed at the Seis- 
mological Laboratory for the purpose. A 
short paper was published by Gutenberg 
and Benioff on some of the results secured. 

During the year the following papers 
were presented: At the meetings of the 
Geological and Seismological Societies of 
America at the California Institute of Tech- 
nology on April 17-18, 1942: "Earthquakes 
and structure in southern California," by 
Beno Gutenberg; "Technique in calculat- 



ing epicenters," by Charles F. Richter; 
"Determination of epicenters and travel 
times in southern California," by Beno 
Gutenberg; "Earthquake magnitude, in- 
tensity, energy and acceleration," by Beno 
Gutenberg and Charles F. Richter; "Gouge 
is not positive fault evidence," by John P. 
Buwalda. At the April 1942 meeting of the 
Mathematical Society at Berkeley: "Math- 
ematical questions in seismology," by 
Charles F. Richter. 

Both Dr. Gutenberg and Dr. Richter 
have devoted a part of their time during 
the year to defense research and instruction. 

BIBLIOGRAPHY 

Gutenberg, B. Mechanism of faulting in south- 
ern California, indicated by seismograms. 
Bull. Seismol. Soc. Amer., vol. 31, pp. 263- 
302 (1941). 

Atmosphere-pressure waves near Pasa- 
dena. Trans. Amer. Geophys. Union, 22d 
annual meeting, pt. 2, pp. 424-426 (1941). 

Tectonic processes now in action. Trans. 

Amer. Geophys. Union, 22d annual meeting, 
pt. 2, pp. 556-558 (1941). 

Is the land around Hudson Bay at present 

rising? (Discussion) Amer. Jour. Sci., vol. 
240, pp. 147-149 (1942)- 

and H. Benioff. Atmospheric waves and 

currents recorded by electromagnetic baro- 
graphs. Proces-Verbaux Assoc. Met., 7th 
General Assembly (Washington, Sept. 1939), 
Union Geod. et Geophys. Internat., pp. 61- 
62 (1941). 

and C. F. Richter. Seismicity of the 



earth. Geol. Soc. Amer., Spec. Paper No. 34. 
131 pages (1941). 

Richter, C. F. Earthquake near Whittier, Cali- 
fornia, January 29, 194 1. Bull. Seismol. Soc. 
Amer., vol. 32, pp. 7-9 (1942). 

Wood, Harry O. A chronologic conspectus of 
seismologic stations. Bull. Seismol. Soc. 
Amer., vol. 32, pp. 97-159 (1942). 



University of Pittsburgh, Pittsburgh, Pennsylvania. Microcalorimetric studies of the 
thermal properties of dilute solutions. (For previous report see Year Book No. 40.) 

These studies were started in September Dr. A. L. Robinson, of the Department 
1940 and have been carried on by Dr. of Chemistry of the University of Pitts- 
William E. Wallace under the direction of burgh, and in cooperation with Dr. R. E. 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



107 



Gibson, of the Geophysical Laboratory of 
the Carnegie Institution of Washington. 

Measurements of the heats of solution 
and dilution of calcium sulfate dihydrate 
in sodium chloride solutions have been 
completed. Results of this investigation 
were presented before the Physical Section 
at the American Chemical Society meeting 
in Memphis, in April 1942. 

The heats of dilution of aqueous glycine 
solutions have been investigated. Results 
of this study have been prepared for pub- 
lication. 

The heats of dilution of some lanthanum 
salts have been under investigation. Satis- 
factory data have been obtained using lan- 



thanum chloride and lanthanum sulfate. 
These results have also been prepared for 
publication. 

The microcalorimeter used in the above 
studies has undergone alteration of such 
nature that nonaqueous solvents can now 
be accommodated. At the present time 
(June 1942) work is in progress involving 
measurements of the heats of dilution of 
sodium chloride in ethylene glycol. 

BIBLIOGRAPHY 

Robinson, A. L., and W. E. Wallace. Some 
heats of dilution and related thermal proper- 
ties of aqueous cadmium halides. Chem. 
Revs., vol. 30, pp. 195-209 (1942). 



Joseph C. Boyce, Massachusetts Institute of Technology, Cambridge, Massachusetts. 
Research in the spectroscopy of the vacuum ultraviolet. (For previous reports see 
Year Books Nos. 38 to 40.) 



This research, supported for three years 
by grants from the Carnegie Corporation 
of New York to the Carnegie Institution 
of Washington, continued into its fourth 
year on an unexpended surplus from 
previous years. Early in the year covered 
by this report it became apparent that 
the demand for trained research workers 
and for shop facilities would soon put a 
stop to all research work not directly con- 
tributing to preparations for war. It was 
therefore decided, before the experienced 
personnel of the project should be scat- 
tered, to discontinue the program of pho- 
tographing additional spectra and to pro- 
ceed with the reduction of observations on 
some representative spectra. In this way 
it would be possible to evaluate the results 
attained to date in this program and in the 
parallel Works Progress Administration 
program for the measurement of the 
spectra. 

The most reliable wave-length standards 
between A2000 and A1300 are those of Cu n 
determined by Shenstone (Philos. Trans. 



Roy. Soc, A, vol. 235, pp. 195-243, 1936) 
and of Fe 11 by Green (Phys. Rev., vol. 55, 
pp. 1209-1217, 1939) and by Edlen (unpub- 
lished data in substantial agreement with 
Green but containing additional lines). 
These are each based on combinations be- 
tween spectroscopic terms which can them- 
selves be located from lines in the longer 
wave-length region of the spectrum. By 
a happy relation (J. C. Boyce, Rev. Mod. 
Phys., vol. 13, pp. 1-57, 1941; see especially 
p. 21) between wave length and wave 
number, at various wave-length regions, 
the wave-length accuracy of these stand- 
ards in the short wave-length region is 
somewhat greater than that of the longer 
wave-length lines used in determining the 
term values. Most of the copper lines arise 
from high levels in the copper ion, not 
ordinarily excited in sparks, and require 
Schiiler cathode excitation. Furthermore, 
there are considerable gaps between stand- 
ards in each of these systems. 

Mrs. Lyman therefore undertook a criti- 
cal study of all available exposures of cop- 



io8 



CARNEGIE INSTITUTION OF WASHINGTON 



per (spark and Schuler tube excitation), 
iron (spark excitation), and mixtures (in 
a pressed-powder electrode) of copper and 
iron (spark excitation), as well as of sparks 
of silver and of silver-copper and silver-iron 
mixtures. Six exposures of copper, two of 
iron, and five of an iron-copper mixture 
were selected which had all been measured 
by means of the Harrison automatic com- 
parator (Jour. Opt. Soc. Amer., vol. 25, 
pp. 169-178, 1935). On every plate ex- 
amined, the values for the wave lengths 
of the lines used were checked as to accu- 
racy in reading the microphotometer films 
and in the arithmetical averaging of the 
six individual readings of each line. In 
most cases only the values of the standards 
on the plates were examined. On one Fe 
plate and four Cu plates, all the lines were 
checked. 

Fe and Fe-Cu. Calibration curves using 
Edlen's Fe standards as true values were 
drawn for the standards from two Fe 
plates. The wave lengths of the lines were 
corrected from the curves. Each of these 
two plates was remeasured on the auto- 
matic comparator. New calibration curves 
were drawn and the values of the stand- 
ards read from the curves. 

Several Fe calibration curves were ob- 
tained from Fe-Cu plates. The corrected 
values of the Fe standards from all the 
Fe and Fe-Cu measurements were as- 
sembled and averaged, and the final values 
corresponded so closely to Edlen's values 
for the standards that his list with the ex- 
ception of a few lines was adopted as the 
Fe standard list. Edlen's Fe standards did 
not uniformly represent the range desired, 
however, so the plates were examined for 
additional lines which might be used as 
standards. Several values for the lines 
picked out were obtained from the respec- 
tive correction curves for those plates. The 
averages of these values were added to the 
Edlen Fe standard list as possible addi- 



tional Fe standards, giving a range of 
standards from A 1400 to A2050. Some of 
the new standards were Fe 11 and some 
Fe in lines. 

Cu and Cu-Fe. Since most of Shen- 
stone's calculated Cu lines appeared only in 
the Schuler tube excitation of Cu and not 
in the spark spectra of Cu, it was necessary 
to pick out spark Cu lines which could 
serve as standards on spark plates. The 
values of the proposed Cu standards were 
read on Cu-Fe plates and corrected by 
means of the Fe calibration curves. The 
Cu standards were read from Cu plates 
and calibration curves for the Cu stand- 
ards drawn. The averages of all the pos- 
sible values of the Cu standards were ob- 
tained (two Cu plates being remeasured 
and read as additional checks). A list of 
Cu spark standards was then compiled 
which covered the range from A1300 to 
A2000. Some of the lines were Cu 11 and 
some Cu in. 

Four Cu Schuler tube plates were also 
read and the measured wave lengths of 
the standards corrected from calibration 
curves containing many of Shenstone's 
calculated Cu lines. 

Ag, Ag-Fe, and Ag-Cu. The Fe and Cu 
standards were then used in an attempt to 
determine some Ag standards. Gilbert's 
work on Ag 111 (Phys. Rev., vol. 47, pp. 
847-850, 1935; vol. 48, pp. 338-342, 1935) 
was used as a comparison with the new 
measurements. A term array of Ag in 
based on the new measurements from 
Ag-Fe plates between A1600 and A1700 and 
between A 1800 and A1950, and on Gilbert's 
values above A2050 was attempted, but the 
results were very unsatisfactory and in very 
poor agreement with Gilbert's values. The 
Ag-Cu plate gave a poor Cu calibration 
curve, and since there were many Ag-Cu 
blends, the attempt to obtain Ag standards 
was abandoned for the time being. 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 



109 



Table 1 presents the previous and the 
added wave-length standards in the range 
from A 1 309 to A2041 in both copper and 
iron, arranged in order of wave length. 
The accuracy of the older data, based on 
the combination principle, is believed to 
range from 0.002 to 0.004 A. The newer 
data are inherently somewhat less accurate, 
but an estimate of 0.005 A as their prob- 
able error seems reasonable. 

Titanium was selected as an element 
whose spectra in the vacuum ultraviolet 
were simple and fairly well understood, 
but for which the published wave-length 
measurements (H. N. Russell and R. J. 
Lang, Astrophys. four., vol. 66, pp. 13-42, 
1927; H. N. Russell, ibid., vol. 66, pp. 283- 
328, 1927) were not of high accuracy. Miss 
Pitkin assembled and checked wave-length 
data from representative exposures of 
titanium and of mixtures of titanium with 
iron and copper. The wave-length stand- 
ards listed in table 1 were used in the re- 
duction of these measurements, as slight 
corrections to the data given by the auto- 
matic comparator. About 60 lines of Ti in 
between A1282 and A1948 were fitted into 
a term array, following Russell and Lang, 
but permitting a considerably more pre- 
cise determination of term values. About 
10 lines which had not been given by 
Russell and Lang could now be classified. 
The multiplet of Ti 11 in the vicinity 
A1910 was remeasured, as were a few lines 
of Ti iv. Publication of these results has 
been deferred until there is opportunity 
to extend the measurements to the region 
of shorter wave lengths. 

The precision of these data, as evidenced 
by the accurate fit into term arrays, as well 
as by the check with Edlen on the iron 
measurements, gives evidence as to the 
reliability of the large amount of data con- 
tained in the collection of spectra. When 
work is resumed after the war, the obser- 
vational program should be directed to- 



ward obtaining spectra from vacuum 
sparks, to give somewhat higher excitation 
than has been obtained in the previous 
observations. This will assist in assigning 
hitherto unclassified lines to the appropri- 
ate stage of ionization and will extend the 
range of the measurements down to per- 
haps A500. At the same time the program 
for the reduction of observations should 
be considerably expanded. The collection 
of films from the Harrison automatic 
comparator will be very useful, as will 
many of the W.P.A. readings and averag- 
ings from these films. As would be ex- 
pected of such results obtained by un- 
trained workers, the recent studies have 
shown that this computational work has 
varying reliability and must be carefully 
checked. 

An important spectroscopic paper pub- 
lished during the year by B. Edlen and 
P. Swings is based in part on data obtained 
in 1937 with the Carnegie spectrograph. 
These investigators have measured the 
third spectrum of iron in the region from 
approximately A500 to A6500 and have 
carried out a very complete term analysis. 
The measurements between A2023 and 
A1382 (some 400 lines) were based exclu- 
sively on plates taken by Edlen while he 
was a guest in this laboratory. The same 
plates gave 150 additional lines attributed 
to Fe in in the regions up to A2338 and 
down to A1017, regions in which the obser- 
vations with the Carnegie instrument were 
overlapped by those with a quartz-prism 
spectrograph and with a grazing-incidence 
vacuum spectrograph, respectively. 

The analysis of Fe 111 by Edlen and 
Swings is the most complete one ever car- 
ried out for the third spectrum of a me- 
tallic element. Of the 34 theoretically pos- 
sible terms of the 3d 6 configuration, 32 
have been found. Of the 74 theoretical 
levels for 3d 5 4S, only 10 high-lying levels 



no 



CARNEGIE INSTITUTION OF WASHINGTON 



TABLE 1 
Previous and new wave-length standards in iron and copper 



Int. 

(ARBI- 


Spectrum 


Fe 


Cu 


Int. 

(arbi- 
trary 
scale) 


Spectrum 


Fe 


Cu 


TRARY 
SCALE) 


Edlen New 


Shenstone New 


Edlen New 


Shenstone New 


4 


II 
II 
II 
II 
II 
II 
II 
II 
II 
II 




1309.463 

1326.394 
1329.654 
1337.544 
1339.463 

1363.501 
1367.952 
1371.451 
1377.477 

1393.126 


3 

3 

2 
2 
5 
5 
3 
5 
5 
4 
5 
5 
5 
5 
5 
4 
5 
5 
5 
2 
4 
5 
5 
5 
4 
6 
1 
4 
5 
4 
4 
4 
4 
3 
5 
4 
4 
5 
6 
2 
4 
1 
5 
5 
5 
3 
3 
4 
5 
4 
5 
3 
1 
5 
2 
4 
2 






1588.542 


3 




II 




1590.164 






1592.967 








1599.415 


4 




II 
II 
II 




1602.387 







1610.922 
1612.805 




4 






1 




1621.695 


5 




II 
II 
II 
II 
II 


1623.090 
1625.520 
1632.665 
1633.906 
1637.398 




3 






2 


1401.756 




1 


1403.722 




2 


II 
II 


1405.605 




4 


1407.160 


1639.945 


4 


1413.685 


II 
II 
II 
II 
II 
II 


1640.150 
1643.576 
1654.476 
1658.771 
1659.479 
1663.220 




3 


1418.779 




1 


II 

II 
II 
II 


1418.851 

1420.901 
1424.714 
1434.994 
1442 . 746 
1448.387 
1456.464 




3 






4 






3 






2 




1665 563 


3 








1669 272 


3 




II 
II 
II 
II 

II 
II 
II 
II 
II 
II 
II 
II 
II 
II 


1673.466 
1674.254 
1674.715 
1676.854 




3 


1460.896 




3 


II 


1463.196 
1472.040 




2 






4 


1472.399 
1472.837 


1682.666 


3 






1683.150 


2 




1478.112 
1489.918 
1498.288 


1685.952 
1686.454 
1686.690 
1689.832 
1690.755 
1691.272 
1693.935 
1696.794 
1699.195 




3 






2 






3 


1502.082 




3 




1506.897 




2 


1509.951 




3 


II 


1522.685 




3 


1532.124 




3 


1533.440 




6 


1537.560 


1704 052 


3 


1548.694 


II 
II 


1708.621 
1712.998 




5 


1549.202 
1550.644 
1551.379 




4 




1713 335 


3 




II 
II 
II 
II 
II 


1716.576 




? 


1551.929 
1558.538 
1558.691 


1717.72 


5 




1724.853 
1724.962 
1726.391 
1731.858 




5 






3 


1561.788 
1566.411 













5 
5 


1566.821 
1568.017 
1569.674 
1570.244 
1573.826 
1574.769 
1574.921 


1732 976 






1740.316 




5 




1751 216 


5 
5 








1754 994 




II 


1761.371 
1764.117 




5 






5 
2 




1766 202 


1581.264 
1583.683 


II 


1772.512 




1 






1780.039 


5 


1584.949 
1588.288 


II 


1793.367 




5 




1798.737 













{Continued on following page) 



SPECIAL PROJECTS: TERRESTRIAL SCIENCES 
TABLE 1 — Continued 



III 



Int. 

(ARBI- 


Spectrum 


Fe 


Cu 


Int. 
(arbi- 
trary 

scale) 


Spectrum 


Fe 


Cu 


TRARY 
SCALE) 


Edlen New 


Shenstone New 


Edlen New 


Shenstone New 


3 






1826.317 


4 
5 
4 
2 
4 
6 
4 
3 
6 
4 
4 
5 
6 
5 
5 
4 
5 
4 
4 
4 
4 
5 


II 
III 

II 
III 

II 

III 

III 

III 

II 

II 

II 

II 

II 

II 

II 

II 

II 

II 


1957.922 
1960.302 
1965.294 




4 


II 
II 
II 
II 


1835.872 
1846.574 
1848.771 
1860.052 




4 






4 




1970.489 


5 




1976.114 




4 


1867.729 


1979.947 


4 


II 
II 
II 
II 

III 

II 

III 

III 

II 

III 

III 

II 


1876.836 
1877.470 


1982.055 
1986.399 




5 






1 


1882.240 


1989 . 849 


5 


1888.734 
1891.501 
1902.388 
1904.790 
1912.905 
1919.556 
1924.517 
1931.486 
1935.299 
1940.003 
1943.459 


1989.957 
1993.247 
1996.405 




4 






3 






4 




2000.339* 


2 




2001.025 
2011.348 
2016.136 




2 






3 






5 




2017.60 


3 




2019.429 
2021.399 
2033.060 
2037.089 
2041.346 




4 






5 






5 


1944.586 




5 


1950.323 











* Blend. 

have not been found. Of the 3d 5 4p, prac- 
tically all theoretically possible levels cor- 
responding to those found in 3d 5 4s have 
been established. The final tables contain 
320 levels and approximately 1500 classified 
lines. 

A considerable extension by Edlen of 
the analysis of the second spectrum of iron 
(Fe 11), using data from the same plates, 
is substantially completed and will be pub- 
lished in due course. 



Miss Pauline Pitkin continued as re- 
search assistant until February 1942, when 
she resigned to accept a position in war 
research. Mrs. E. R. Lyman, who joined 
the project in June 1941, resigned in De- 
cember, also to do scientific work in con- 
nection with the war. 

BIBLIOGRAPHY 

Edlen, B., and P. Swings. Term analysis of the 
third spectrum of iron (Fe in). Astrophys. 
Jour., vol. 95, pp. 532-554 (1942). 



W. H. Newhouse, Massachusetts Institute of Technology, Cambridge, Massachusetts. 
Spectro graphic studies of minor elements in minerals. (For previous report see 
Year Book No. 40.) 



Analytical work has continued on the 
variations of minor elements in mineral 
deposits. The qualitative work has been 
completed on the examples described in 
Year Book No. 40. In order to leave no 
gaps in the data, all the minerals present 
to the extent of 5 per cent and more have 
been hand-picked and separately ana- 



lyzed. Mixtures containing the less abun- 
dant and particularly the fine-grained min- 
erals were analyzed to make certain that 
all elements present in the mineral de- 
posits were identified. Over 800 analyses 
have been made, with examination for 
approximately 50 elements in each. 
Quantitative work has been completed 



112 



CARNEGIE INSTITUTION OF WASHINGTON 



during the past year on the most wide- 
spread and abundant mineral, magnetite, 
and is now in progress on the feldspars 
and micas. Fifty magnetites from the var- 
ied geological environments selected for 
study were quantitatively analyzed for ele- 
ments that showed some regularity in var- 
iation. These elements are zinc, nickel, 
cobalt, magnesium, vanadium, chromium, 
and strontium. 

Some difficulty has been experienced in 
finding suitable internal standards for use 
in the quantitative work on these silicate 
minerals. This follows from the large var- 
iation in most of the main chemical ele- 
ments present in the various members of 



these groups. Further conclusions must 
await the analytical data now being ob- 
tained. 

The results of work in cooperation with 
Dr. Clifford Frondel on the spatial dis- 
tribution of minor elements in single crys- 
tals of galena (PbS) and calcite (CaC0 3 ) 
are described in a paper now in course of 
publication. 

BIBLIOGRAPHY 

Bray, J. M. Spectroscopic distribution of minor 
elements in igneous rocks from Jamestown, 
Colorado. Bull. Geol. Soc. Amer., vol. 53, 
pp. 765-814 (1942). 

Chesley, F. B. Investigation of the minor ele- 
ments in diamond. Amer. Mineralogist, 
vol. 27, pp. 20-36 (1942). 



PUBLICATIONS IN CONNECTION WITH OTHER PROJECTS 



Perret, Frank A. Notes on the volcanism of 
the West Indies. Proc. 8th Amer. Scientific 



Cong. (Washington, May 1940), vol. 4, pp. 
751-756 (1942). 



DIVISION OF PLANT BIOLOGY 



Central Laboratory located at Stanford University, California 
H. A. SPOEHR, Chairman 



For many years it has been generally 
assumed that the process of photosynthe- 
sis is fundamentally the same in all plants. 
Although it has been realized that in some 
of the lower forms of plant life, such as 
the purple bacteria, certain differences ex- 
ist, the view has been commonly held that 
the photosynthetic apparatus, and also the 
products which are elaborated through this 
apparatus, are the same throughout the 
plant kingdom. Very little regard has 
been paid to the fact that the great diver- 
sity of plant forms which possess the power 
of photosynthesis represents a tremendous 
variance in evolutionary history and in 
range of adaptability, and considerable dif- 
ference in chemical composition. It is, 
moreover, somewhat difficult to conceive 
that the geological evidences of photosyn- 
thetic activity, presumably represented by 
deposits of petroleum and carbonaceous 
material, had their origin in the photosyn- 
thetic process as we know it to occur to- 
day. That all plants do not contain the 
same photosynthetic apparatus has now 
been demonstrated by the discovery in 
diatoms, brown algae, and red algae of 
chlorophylls and yellow pigments which 
are different from the corresponding pig- 
ments existing in higher plants. Whether 
or not this difference in the photosynthetic 
apparatus is reflected in differences in the 
products elaborated remains to be estab- 
lished. 

Pigments absorb the radiant energy es- 
sential to the production of carbon com- 
pounds by autotrophic organisms. Thus 
far little has been learned about how this 
absorbed energy is utilized in the synthetic 
processes carried out in plants. It is not 



known to what extent each of the several 
green and yellow leaf pigments participates 
in this natural production of organic mat- 
ter. It is believed that much can be 
learned from comparison of the light-ab- 
sorbing properties of the individual pig- 
ments with the effect produced in the plant 
by light of various wave lengths. Such 
comparisons are dependent upon prepara- 
tion of the pure pigments and upon precise 
determination of their spectral absorption 
properties. 

For comparative purposes it is desirable 
to study organisms that differ considerably 
with respect to the pigments of the photo- 
synthetic apparatus. Indications that dif- 
ferent varieties of photosynthetically active 
pigments occur in different classes of algae 
have made necessary a more exact investi- 
gation of the pigments of these organisms. 
Advances that have been made in this in- 
vestigation have been due largely to im- 
provement of the sensitive chromato- 
graphic adsorption method of analysis and 
to use of spectral absorption measurements. 
By these means it has been possible to 
establish that most of the higher plants 
contain the same green and yellow leaf 
pigments, and to determine the differences 
which exist in regard to the photosyntheti- 
cally active pigments between the higher 
and lower forms of plant life. These dis- 
coveries have raised a number of impor- 
tant questions regarding the variability of 
the photosynthetic apparatus throughout 
the plant kingdom and the possible bear- 
ing of this on the nature of the products 
which are formed. These findings may 
also contribute to a more exact systematic 
classification of some of these organisms 



"3 



ii4 



CARNEGIE INSTITUTION OF WASHINGTON 



on the basis of their pigment complex and 
to better understanding of the phyloge- 
netic relations between various algae. 

Diatoms are widely distributed both in 
marine and in fresh waters. In the open 
ocean these minute plants usually are 
present in quantities exceeding those of 
all other forms of plant life, and it is prob- 
able that the total production of organic 
matter by diatoms exceeds that by any 
other class of plants. These organisms also 
flourished in past ages, as is indicated by 
the many extensive deposits of diatoma- 
ceous earth, consisting of the siliceous cell 
walls of diatoms. There is some evidence 
that many petroleum deposits have origi- 
nated in organic materials manufactured 
by diatoms. 

Despite the importance of diatoms in 
the carbon economy of nature, relatively 
little specific information is available con- 
cerning their chemical composition or the 
nature of their metabolism. Apparently 
the storage products of photosynthesis in 
diatoms are largely oils or oil-like sub- 
stances, in contrast with the carbohy- 
drates usually stored by higher plants. 
The question arises: are these different 
products the result of different photosyn- 
thetic mechanisms in the two groups, or 
merely of differences in secondary meta- 
bolic reactions? Differences in the photo- 
synthetic pigment systems support the 
view that there may be fundamental dif- 
ferences between the photosynthetic proc- 
ess in diatoms and the corresponding 
process in higher plants or green algae. 

Methods have been devised and appa- 
ratus has been constructed for the growing 
of relatively large quantities of these or- 
ganisms in pure culture. The investiga- 
tions are planned to yield information on 
the components of the photosynthetic ap- 
paratus, the composition of the photosyn- 
thetic products, and the type of photosyn- 
thetic reaction which occurs in these or- 



ganisms. They are particularly favorable 
material for the investigation of the in- 
fluence of different environmental factors 
on photosynthetic and metabolic activities, 
for which higher plants are in many re- 
spects less suitable. In order to gain a suf- 
ficiently comprehensive view of these func- 
tions of plants it is necessary to obtain data 
from plants representing different stages 
in the evolutionary scale. 

The usual conception of the photosyn- 
thetic reaction is that the carbon dioxide 
absorbed by an illuminated plant is 
converted completely into carbohydrates. 
Many experiments have demonstrated the 
increase of carbohydrates during photosyn- 
thesis, but none of them has shown that 
carbohydrates are the only substances pro- 
duced. A clear-cut demonstration of 
whether or not carbohydrates are the only 
products of photosynthesis is of funda- 
mental significance to the understanding of 
the chemistry of this process. If carbon 
dioxide is transformed quantitatively into 
carbohydrates by the photosynthetic reac- 
tion, then all other substances elaborated 
by the plant must arise from subsequent 
transformations of carbohydrates. This 
would automatically separate all the chemi- 
cal reactions occurring in plants into two 
main groups: the photosynthesis of car- 
bohydrates, and the conversion of carbo- 
hydrates into all the rest of the organic 
substances which may be found in plants. 

Because of the fundamental nature of 
this postulate, it is being made the subject 
of critical examination by as precise in- 
vestigation as possible of the relation be- 
tween the quantity of carbon dioxide ab- 
sorbed by photosynthesizing organisms 
and the nature and quantity of organic 
material formed therefrom. Detailed ob- 
servations on sunflower leaves have tended 
to support the postulate, for a close quanti- 
tative equivalence between the carbon di- 
oxide absorbed and the carbohydrates 



DIVISION OF PLANT BIOLOGY 



"5 



formed has been obtained. It remains to 
be demonstrated whether the small devia- 
tion from exact equivalence is due to the 
diversion of a small fraction of the carbon 
dioxide to the synthesis of substances other 
than carbohydrates, or whether it is due 
to the subsequent rapid conversion of the 
photosynthesized carbohydrates into other 
products. The sunflower plant which was 
used as experimental material for these 
tests is a very effective carbohydrate syn- 
thesizer. It remains to be determined 
whether in other plants, particularly in 
those of a lower evolutionary level, the 
photosynthetic process follows the same 
course. 

The structural elements of higher plants 
are composed primarily of cellulose and 
varying amounts of polyuronides such as 
hemicelluloses, pectin, and gums. The 
polyuronides are extremely complex com- 
pounds composed of five- and six-carbon- 
atom sugars combined with uronic acids in 
various ways. Virtually nothing is known 
concerning the mode of formation of 
polyuronides, of the role they play in the 
economy of the plant, or of their dietetic 
value, although they constitute a very con- 
siderable part of the farm and forest crops. 
Within recent years compounds containing 
uronic acid units have gained added in- 
terest because of their significance for cer- 
tain aspects of detoxication and immunol- 
ogy in the animal organism. 

The idea has been advanced that the 
polyuronides are formed from starch, 
which of course is widely distributed in 
plants, through the oxidation of a part 
of the starch molecule. Efforts have been 
made to carry out such a reaction in vitro 
with a view to accomplishing the trans- 
formation of the starch molecule into a 
uronic acid. Uronic acids are characterized 
by the fact that when heated with 12 per 
cent hydrochloric acid they yield about 25 
per cent of carbon dioxide. They can also 



be identified by means of a very charac- 
teristic color reaction with naphthoresorci- 
nol. By oxidation of starch, under care- 
fully controlled conditions, with hydrogen 
peroxide in the presence of a small amount 
of an iron salt, an interesting product was 
obtained which lost carbon dioxide with 
great ease in amounts corresponding to 
those yielded by a uronic acid, but which 
proved not to be of this category of com- 
pound. Evidence was obtained that the 
starch molecule, in the course of its oxida- 
tion with hydrogen peroxide, splits into 
units of more than six carbon atoms, 
forming the same product which is ob- 
tained from maltose by the same oxidizing 



agent. 



In furtherance of the objective of experi- 
mental taxonomy to extend knowledge re- 
garding the processes of evolution in flow- 
ering plants, several kinds of experiment 
are in progress. During the past year stud- 
ies on the nature of climatic races have 
been emphasized, because these are appar- 
ently among the most important steps in 
the building up of larger evolutionary 
units. For these studies naturally grow- 
ing populations of the yarrow, Achillea, 
and of Potentilla, a. close relation of the 
strawberry, have been investigated. These 
have been brought from diverse environ- 
ments into cultivation under similar con- 
ditions. Observations on these, and genetic 
experiments on the Madiinae, are reveal- 
ing the structure and relationships of cli- 
matic races. For such studies a much more 
intensive sampling of populations is neces- 
sary than was used in the previously com- 
pleted transplant experiments. Such pro- 
cedure makes possible a more adequate ap- 
praisal of the continuities or discontinuities 
that exist among climatic races. 

In central California, populations of 
Achillea occur from the coastal bluffs at 
the Pacific to near the crest of the Sierra 
Nevada at 11,000 feet elevation, and east- 



n6 



CARNEGIE INSTITUTION OF WASHINGTON 



ward across the Great Basin and north- 
ward to Alaska. Two species meet on the 
lower western flank of the Sierra Nevada. 
These are marked by a difference in chro- 
mosome number that is an effective bar- 
rier to interbreeding. Yet the differences 
in form between the races within each 
species are very much greater than those 
between the contiguous races of the two 
species. 

The climatic races of Achillea differ by 
many characters affecting both the form of 
the plants and their response to the en- 
vironment. The distribution of the races 
closely parallels the major climatic belts 
found in a transect across California, as 
identified by the life zones. There are 
many colonies of each climatic race. Sam- 
ples of colonies of Achillea taken at fre- 
quent intervals across California show that 
as one moves inland from the coast some 
miles, the dominating influence is roughly 
the distance from the sea. Farther inland, 
as in the Sierra Nevada, the dominating 
influence becomes altitude. Though each 
colony shows a marked diversity of herit- 
able variation, as a whole it reflects the 
kind of habitat to which it is native. 

It is too early to state whether the varia- 
tion observed within and between climatic 
races is essentially continuous or discon- 
tinuous, but almost all the colonies under 
study contain a small percentage of in- 
dividuals with characteristics of the adjoin- 
ing climatic races. This observation fre- 
quently applies to such characters as time 
of flowering and winter dormancy, and 
may extend to other physiological charac- 
ters. This suggests the possibility that 
within natural colonies new forms may 
originate through genie recombination and 
natural selection. 

No precise information is at hand con- 
cerning the nature of the physiological 
differences that mark climatic races. This 
important gap in the information needed 



for a clear understanding of evolutionary 
processes has been realized for some time. 
The intensive sampling and study of colo- 
nies of Achillea and Potentilla is giving es- 
sential information and materials for ex- 
periments in comparative physiology. In 
these experiments it is planned to compare 
the effects of one environmental variable 
on several basic physiological functions 
under controlled conditions, using plants 
of very different climatic races. 

An apparatus for quantitative physio- 
logical experiments of this type has been 
designed and partly constructed. Radia- 
tion, temperature, and relative humidity 
can be regulated within broad limits. This 
equipment is to be used in the study of 
photosynthesis, respiration, and absorption 
of water by roots. Another apparatus, de- 
signed for exploratory experiments on the 
effect of different soil temperatures on 
growth of different climatic races, has been 
constructed and put into operation. 

During past years considerable attention 
has been given to field investigations of the 
influence of environment on plants. Sev- 
eral of these projects have recently been 
brought to completion. The functioning 
of living organisms under the extremely 
severe environmental conditions of the 
desert presents an extraordinarily complex 
picture. The results of investigations in 
this field are now also being assembled for 
publication. It was essential, first of all, 
to obtain a picture of the vegetation of 
the arid regions on the background of the 
complex of environmental conditions of 
which the vegetation is a product. This 
has been done by means of extensive ex- 
ploration and study of the composition, 
relationships, and distribution of the desert 
vegetation. In these investigations the 
study of the plant and of the environment 
have gone hand in hand. 

The impression given by a desert land- 
scape is largely made by its plants. Their 



DIVISION OF PLANT BIOLOGY 



117 



wide spacing, low stature, and many highly 
specialized forms create plant communities 
of distinctive aspect. Plants living near the 
limits of existence are more sensitive than 
others to small differences in environmen- 
tal conditions. From this responsiveness 
follows the great variety of plant com- 
munities that distinguishes the different 
parts of the desert. In the field work of 
the past ten years it has been possible to 
examine at least a very high percentage 
of the communities found in the central 
and southern parts of the North American 
Desert. The physiognomy, structure, and 
composition of the communities have been 
determined. An understanding of the de- 
pendence of each community on a particu- 
lar group of climatic and soil conditions 
has been approximated, but its precise de- 
termination in each case would require 
investigation far beyond the limits of the 
current projects. 

The exploration of desert areas in Texas 
and on the Mexican plateau during the 
past four years has modified some of the 
conceptions based on earlier work in Ari- 
zona and Sonora. Particularly it has re- 
vealed a wider range of climatic conditions 
under which desert vegetation is found. 

Low rainfall is the basis of desert, but 
it is neither a simple nor an isolated factor 
in relation to plants. Over much of the 
southwestern United States there is a close 
correlation between rainfall and vegeta- 
tion, but in northern Mexico the correla- 
tion is highly modified. A study of avail- 
able rainfall data for the entire North 
American Desert and the adjacent regions 
has been found necessary to an understand- 
ing of local conditions in any part of 
this area. 

The forces of the environmental com- 
plex are constantly changing in relative 
intensity and effectiveness. Many of these 
environmental and climatic influences are 
clearly discernible in the form and dis- 



tribution of living organisms. The world 
today represents the resultant of past and 
present forces. The past has significance 
in so far as it enables us to understand the 
present and in a measure to predict the 
future. 

Plants of later geologic time provide one 
of the best means for reconstructing the 
topography and climate of the past. They 
are closely related to modern plants, whose 
environmental requirements may be read- 
ily determined and projected back into 
ages before man lived upon the earth. 
Many Tertiary forests were made up of 
elements which now live under varied con- 
ditions in widely separated parts of the 
world. In his search into the record of 
earth history, the paleobotanist must fit 
together the evidence of such forests, and 
draw a picture of yesterday colored by his 
knowledge of today. 

Many millions of years ago the vegeta- 
tion of Oregon included a mixture of such 
conifers as swamp cypress and redwood, 
trees now living on opposite sides of the 
continent. Mingled with them were black 
oaks and hickories like those growing in 
the cypress swamps of Indiana, together 
with tan oaks and maples whose modern 
descendants live with the redwood in Cali- 
fornia. The disappearance of these trees 
from Oregon during the long years since 
the Miocene has been largely the result of 
climatic changes associated with the uplift 
of the Cascade Range. Their survival in 
Indiana and California has been made pos- 
sible by the continuance there of living 
conditions like those of the past. There is 
reason to believe that earth changes may 
further alter the distribution of forests, 
that the planet on which we live has not 
reached the end of its dynamic course, 
and that man as well as plants will con- 
tinue to be modified by the trend of its 
future history. 



II 



<s 



CARNEGIE INSTITUTION OF WASHINGTON 



Dr. Emmett Martin has been called to 
special scientific work in connection with 
the war; Malcolm Nobs, assistant in taxon- 



omy, has joined the Army; and R. F. Lucy, 
who has served as part-time artist, has 
joined the Coast Guard. 



BIOCHEMICAL INVESTIGATIONS 



H. A. Spoehr, J. H. C. Smith, H. H. Strain, W. M. Manning, H. W. Milner, and G. J. Hardi 



Pigments of Diatoms and Algae 

Diatom pigments. Considerable previ- 
ous work had failed to give a clear under- 
standing of the green and yellow pigments 
contained in diatoms. It was generally 
recognized that chlorophyll a was the prin- 
cipal green pigment (as in higher plants), 
that fucoxanthin was the principal xantho- 
phyll, and that beta-carotene was the prin- 
cipal carotene. It was uncertain whether 
another green pigment observed in ex- 
tracts of diatoms was chlorophyll b (the 
second green pigment of higher plants) 
or chlorofucine (a chlorophyll-like pig- 
ment first observed in brown algae and 
often reported to be a post mortem prod- 
uct). The nature of the diatom xantho- 
phylls other than fucoxanthin and their re- 
lation to the common leaf xanthophylls 
was not known. 

Analysis by Drs. Strain and Manning 
of diatoms (Nitzschia closterium grown in 
pure culture) has revealed that chloro- 
fucine as well as chlorophyll a occurs in 
the diatom extracts. When the cells were 
killed under various conditions and ex- 
tracted with methanol, the same propor- 
tions of chlorofucine and chlorophyll a 
were always obtained. Chlorofucine is, 
therefore, to be regarded as a normal con- 
stituent of the diatoms and not as a post 
mortem product. 

Chlorofucine absorbs relatively very 
much less light in the red region of the 
spectrum than in the blue. Comparison of 
its spectral absorption curve with that of 
chlorophyll a revealed that, for methanol 
extracts of diatoms in the spectral region 



between 455 and 490 mu, chlorofucine ab- 
sorbs considerably more light than chloro- 
phyll a. This indicates that chlorofucine 
may play an important role in the photo- 
synthetic activity of diatoms. 

Especially sensitive adsorption methods 
for the detection of chlorophyll b in plant 
extracts were developed and applied to ex- 
tracts of diatoms. No trace of this pig- 
ment was observed. 

In conformity with earlier investigations, 
fucoxanthin was found to be the principal 
xanthophyll in the diatom extracts. In ad- 
dition, however, this pigment was found to 
exist in at least three forms that are readily 
interconvertible by heat or by traces of 
iodine. Extraction of the cells under mild 
conditions always gave the same mixture 
of these three fucoxanthins. Unless a rapid 
interconversion takes place immediately 
upon death of the cells, all three fuco- 
xanthins probably represent normal con- 
stituents of the diatoms. 

The principal, most stable fucoxanthin 
represents about 90 per cent of the equilib- 
rium mixture. It is adsorbed below the 
other two on columns of sugar. It shows 
a single definite spectral absorption maxi- 
mum (452 mu in ethanol). Each of the 
other two isomers shows a spectral absorp- 
tion maximum about 6 to 7 mu nearer 
the violet region of the spectrum. By 
analogy with other carotenoid and polyene 
compounds, these interconvertible fuco- 
xanthins probably differ in the spatial ar- 
rangements about double bonds in the 
molecules. 

Earlier work by Dr. Strain had shown 



DIVISION OF PLANT BIOLOGY 



II 9 



that the xanthophylls of higher plants can 
also be converted into isomeric pigments, 
but only the most stable isomers had been 
observed in leaves. The occurrence of 
several labile fucoxanthin pigments in dia- 
toms, coupled with the fact that fucoxan- 
thin appears to play a role in photosynthe- 
sis, suggests that this isomerization may be 
associated in some way with the function 
of the pigment in the photosynthetic re- 
actions. 

In addition to the three isomeric fuco- 
xanthins, diatoms contain appreciable 
quantities of several other xanthophylls. 
One of these is weakly adsorbed and passes 
rapidly through the adsorption columns. 
Its spectral absorption curve is similar to 
that of zeaxanthin, but the absorption 
maxima are at slightly shorter wave 
lengths. Another xanthophyll present in 
somewhat larger quantities is remarkably 
similar to lutein, the principal xanthophyll 
of higher plants. This pigment and lutein 
show so nearly identical spectral absorption 
curves that they can easily be confused. 
They can be differentiated with certainty 
only by the slightly greater chromato- 
graphic adsorbability of the diatom pig- 
ment. Not one of the common leaf xantho- 
phylls was detected in diatoms. 

There is a marked difference between 
the spectral absorption curves of the fuco- 
xanthins and those of the other xantho- 
phylls and the carotene found in diatoms. 
For example, at a wave length of about 
540 mu fucoxanthins absorb considerable 
light, whereas the carotene and the other 
xanthophylls absorb virtually none. This 
fact has been made use of, in conjunction 
with the spectral curves of the several pig- 
ments, to calculate the amount of light ab- 
sorbed by the different groups of pigments 
in the diatom extracts. At all wave lengths 
in the visible spectrum, chlorophyll a, 
chlorofucine, and the fucoxanthins to- 
gether absorb 70 per cent or more of the 



total amount of light absorbed by all 
the pigments in the methanol extracts. 
Whether or not these same relations hold 
in other solvents and in the leaf might be 
investigated with profit. 

The photosynthetic apparatus of the 
diatoms has been varied by culture of the 
organisms in light of different spectral 
properties. Diatoms grown in "neon" 
light show a large increase in the lutein- 
like xanthophyll as compared with organ- 
isms grown in white light. When diatoms 
are transferred from white to "neon" light, 
this change takes place slowly and be- 
comes substantial only after several gen- 
erations of diatoms have been grown un- 
der the new light conditions. These ob- 
servations point the way to two impor- 
tant fields of biological investigation. They 
indicate that products of probable func- 
tional importance may be varied a great 
deal in response to changes in external 
or environmental conditions. By careful 
control of external conditions it may be- 
come possible to vary at will the chemical 
products of Nature's greatest factory, the 
green parts of plants. Because changes of 
this nature may be involved in the early 
stages of the development or evolution of 
plant varieties, further studies of the physi- 
ological response of unicellular, autotroph- 
ic organisms to their environment may 
yield new methods and fresh views per- 
taining to the development of plant types. 

Pigments of brown algae. Reports of the 
occurrence of both chlorofucine and fuco- 
xanthin in brown algae prompted an ex- 
amination of the pigments of several rep- 
resentatives of this group of plants. All the 
ten species examined contained chlorophyll 
a and chlorofucine. Chlorophyll b was not 
detected. All these species contained mix- 
tures of the three fucoxanthins and all 
contained beta-carotene. Although lutein 
had been reported previously as a constitu- 
ent of the brown algae, all the species ex- 



120 



CARNEGIE INSTITUTION OF WASHINGTON 



amined contained instead several other 
xanthophyll pigments with spectral absorp- 
tion properties similar to those of xantho- 
phylls found in green leaves. One of these 
pigments resembled flavoxanthin; two of 
them were similar to violaxanthin. One 
of these violaxanthin-like pigments is very 
difficult to separate from the flavoxanthin- 
like pigment; the other is adsorbed near 
the principal fucoxanthin on the adsorp- 
tion column. The lutein-like xanthophyll 
found in diatoms was not observed in ap- 
preciable quantities in the brown algae. 

Like the diatoms, the brown algae are 
widely distributed and of great quantita- 
tive importance over large areas. This 
lends further support to the view that both 
chlorofucine and fucoxanthin may be im- 
portant pigments in the carbon economy 
of nature. 

A new chlorophyll from red algae. Fur- 
ther clues to the natural variability of the 
photosynthetic apparatus have been ob- 
tained from a cursory examination of the 
pigments of red algae. None of the species 
examined, representing some six or eight 
genera, contained either chlorophyll b or 
chlorofucine. In addition to chlorophyll a 
they yielded smaller quantities of another 
green pigment, a hitherto undescribed 
chlorophyll. This new chlorophyll shows 
maximum absorption far in the red and 
violet regions of the spectrum (maxima 
at 696, 456, and 401 m|j in methanol). Be- 
cause the absorption maximum in red light 
is so far removed from that of chlorophyll 
a (665 rap in methanol), the new chloro- 
phyll is readily detectable by spectroscopic 
examination of methanol extracts of the 
algae. Relatively to the chlorophyll a, the 
quantity of the new chlorophyll varies a 
great deal in different species. The larg- 
est amounts have been found in two spe- 
cies of Gigartina (Agardhii and papillatd) 
and in Erythrophyllum. 

On adsorption columns of sugar, the 



new algal chlorophyll is adsorbed not far 
above chlorophyll a and just below where 
chlorophyll b would occur. In the light of 
our experience with adsorption columns, 
this behavior suggests that the new pig- 
ment is probably closely related to chloro- 
phylls a and b. When treated with acid 
this chlorophyll is converted into a gray 
pigment, pheophytin, that is very similar 
to or identical with the pheophytin ob- 
tained from chlorophyll a. This indicates 
a close relationship between chlorophyll 
a and the new algal chlorophyll. 

In white light, solutions of the new 
chlorophyll are weakly fluorescent, but 
this apparent weakness of the fluorescent 
light may be due to the insensitiveness of 
the eye to light of such great wave length. 
In ultraviolet light, solutions of the new 
chlorophyll are bright red. 

In view of the fact that the red-algal 
chlorophyll absorbs light in the far red 
region of the spectrum, where other pig- 
ments do not absorb appreciably, it should 
be possible by quantum-yield measure- 
ments to determine with certainty whether 
or not light absorbed by this chlorophyll is 
utilized in photosynthesis. 

Implications. For many years it has been 
generally thought that the chlorophyll pig- 
ments in plants are subject to little or no 
variation. These investigations of dia- 
toms, brown algae, and red algae indicate 
that the chlorophylls and also the yellow 
pigments in different algal classes are 
much more variable than was previously 
supposed. 

These results justify the belief that the 
photosynthetic mechanism is not neces- 
sarily identical in all groups of plants. The- 
ories concerning the mechanism of photo- 
synthesis, and of energy transfer between 
pigments, should be re-examined in the 
light of these possible variations. Further 
investigations of the photosynthetic process 
in various algae are certainly to be desired. 



DIVISION OF PLANT BIOLOGY 



121 



The results of these pigment studies 
thus far also justify the belief that investi- 
gations of this type may provide an addi- 
tional key to phylogenetic relations be- 
tween the various algae. Taxonomists are 
able to place practically all known algae in 
a few well defined classes, but they are not 
able so easily to tell the probable relations 
between the various classes. Pigments re- 
lated to the photosynthetic mechanism are 
of basic importance to the plant and must 
reflect some of the most important charac- 
teristics of its genetic makeup. It is reason- 
able to suppose that, in general, two groups 
of plants having several pigments in com- 
mon are more closely related than groups 
having fewer pigments in common. With- 
out considering other lines of evidence, 
at least two tentative conclusions can be 
drawn from this work thus far. One is 
that the green algae are less closely related 
to the groups of algae which have been in- 
vestigated than they are to the higher 
plants. The other is that diatoms are prob- 
ably more closely related to the brown 
algae than either group is to red algae or 
to green algae. These conclusions are 
based on the observations that (i) chloro- 
phyll a and beta-carotene are probably the 
only pigments occurring in green algae 
and higher plants which also occur in per- 
ceptible amounts in diatoms and brown 
algae; (2) diatoms and brown algae have 
in common (in addition to chlorophyll a 
and beta-carotene) chlorofucine and the 
various fucoxanthin isomers; (3) red algae 
contain neither chlorofucine nor chloro- 
phyll b but do contain another chloro- 
phyll not found in diatoms and brown 
algae. 

Obviously a detailed study of the green 
and yellow pigments in other groups of 
algae should yield many more clues re- 
garding genetic relationships. 



Biochemical and Physiological Study 
of Diatoms 

To aid in the study of the chemistry and 
physiology of diatoms, it was found de- 
sirable to produce in pure culture relatively 
large quantities of diatoms (several grams 
at least). A gram of diatoms does not 
sound like a very large quantity until one 
undertakes to grow that amount in pure 
culture. In round numbers a gram (dry 
weight) of the marine diatom Nitzschia 
closterium, as commonly cultured, repre- 
sents a hundred billion diatoms in 10 liters 
of sea water. Drs. Manning and Hardin 
have undertaken the isolation and culture 
of a number of different species of diatoms 
and other algae to be used in these in- 
vestigations. 

Culture methods. A glass culture ves- 
sel of 1 o-liter capacity has been assembled 
and put in operation for growing Nitzsch- 
ia closterium, with provisions for main- 
taining the culture pure (i.e., uncontami- 
nated with bacteria or other organisms). 
Air is supplied to the culture vessel by 
means of an aquarium pump, the air be- 
ing filtered through sterile cotton before 
being admitted to the culture. Light is 
furnished by a spiral consisting of approxi- 
mately 36 feet of "snow white" fluorescent 
tubing, which surrounds the vessel and 
furnishes an illumination approximately 
equivalent to one-eighth of full sunlight. 
Light of such intensity unfortunately 
brings with it considerable heat even from 
the relatively cool fluorescent light source. 
This heat, if not removed, would soon kill 
the diatoms in the culture. To conduct the 
heat away as rapidly as possible, chilled 
water is circulated through a cooler, con- 
structed from two large concentric glass 
cylinders, which is inserted into the cul- 
ture vessel. Additional light is provided 
by several turns of fluorescent tubing in- 
serted in the inner cylinder. Provision is 



122 



CARNEGIE INSTITUTION OF WASHINGTON 



made for drawing off portions of the 
culture from time to time and adding 
fresh sterile culture solution without in- 
troducing contamination. By this proce- 
dure it is possible to maintain the culture 
in approximately constant physiological 
condition and to obtain fairly large quan- 
tities of material at regular and frequent 
intervals. The procedure is very satisfac- 
tory for maintaining cultures of Nitzschia 
closterium except that the temperature 
problem is made somewhat difficult by 
the relatively low heat tolerance of this 
diatom. If the temperature of the culture 
rises much above 19 ° C. the multiplication 
rate is seriously reduced. 

To supplement the studies with Nitzsch- 
ia, and with the hope that perhaps some 
fresh-water diatom will have a greater 
tolerance for high temperatures and be 
equally satisfactory in other respects, the 
possibility of substituting a fresh-water 
form for the marine one is now being 
investigated. To date six species of fresh- 
water diatoms have been obtained in 
pure culture. Before mass culturing of 
these species is attempted it will be neces- 
sary to determine the best available condi- 
tions for their culture, and such studies 
are now under way. Besides giving a 
larger field from which to select forms 
most amenable to laboratory study, the 
obtaining and study of many different 
species of diatoms has the advantage of 
rendering more secure any generalizations 
that may be made about the metabolism of 
diatoms. 

For purposes of comparison, it is also 
planned to culture unicellular algae other 
than diatoms. Sufficient equipment has 
been assembled for the simultaneous opera- 
tion of three large culture vessels. One of 
the light sources consists of neon-filled tub- 
ing instead of fluorescent tubing. 

In the preliminary culturing of diatoms 
one curious observation has been made 



which merits mention and further study. 
It is generally true that a pure culture of 
an alga will grow in the presence of glu- 
cose and usually will grow much more 
luxuriantly than in a simple mineral me- 
dium where it must synthesize its own or- 
ganic matter. It has been found, however, 
that the growth of the diatom Nitzsch- 
ia closterium is completely stopped in 
rather low concentrations of glucose (0.1 
per cent). This observation certainly bears 
on the supposed course of photosynthesis. 
One would expect any substance in the 
direct line of photosynthetic products to 
be utilized by the organism. If this is a 
valid assumption, it would appear improb- 
able that glucose is involved in the photo- 
synthetic process of the one diatom species 
tested to date. Obviously more work bear- 
ing on this point needs to be done. 

Measurement of photosynthesis. An ap- 
paratus has been assembled for measuring 
photosynthesis in diatoms or other plank- 
ton algae under conditions which should 
permit the algae to continue normal 
growth during fairly extended periods of 
measurement. Another feature of the ap- 
paratus is provision for measuring rates 
both of carbon dioxide uptake and of oxy- 
gen evolution. The ratio of these rates 
gives an indication of the types of prod- 
uct being formed by a plant during a 
period of photosynthesis. The 2-liter re- 
action vessel which is employed for the 
photosynthetic measurements accommo- 
dates a volume of algal suspension large 
enough to permit direct chemical analysis 
of the material which has undergone a 
period of measured photosynthesis. The 
combination of chemical analysis and de- 
tailed photosynthetic measurements on the 
same material should provide information 
not otherwise obtainable regarding the 
photosynthetic and other metabolic prod- 
ucts of diatoms. 



DIVISION OF PLANT BIOLOGY 



123 



The Nature of the Photosynthate in 
Sunflower Leaves 

For many years it has been known that 
carbohydrates make up a considerable 
portion of the organic matter produced 
by photosynthesis in higher plants. How 
nearly carbohydrates constitute all the 
organic matter thus produced has been 
tested in only a few cases. In these cases 
the amount of carbohydrate material re- 
covered fell far short of the quantity antici- 
pated from the amount of carbon dioxide 
absorbed. 

Dr. Smith, assisted by Dr. S. S. Todd 
and Mr. D. Frazier, has undertaken an 
accurate investigation of the nature and 
amount of the organic matter formed dur- 
ing the illumination of sunflower leaves 
in relation to the amount of carbon diox- 
ide absorbed. Indirect evidence of the na- 
ture of the photosynthate (the organic 
matter formed during photosynthesis) was 
obtained from a determination of the in- 
crease in dry weight produced in a leaf 
by the assimilation of a known quantity of 
carbon dioxide. For this purpose the 
two halves of a leaf, separated from the 
midrib, were used. One half was placed 
in an atmosphere containing carbon di- 
oxide and illuminated, and the amount of 
carbon dioxide that it absorbed measured. 
The other half was kept in the dark and 
served as a control. From dry-weight de- 
terminations on the two portions of the 
leaf, the increase in dry weight of the il- 
luminated portion was obtained. The pro- 
cedure made it certain that the transfer of 
material to and from the leaf could take 
place only through the atmosphere sur- 
rounding the leaf. That this was true was 
demonstrated by combustion analyses, 
which showed that the increase in the car- 
bon content of the illuminated leaf was 
equal to the decrease in carbon content 
of the atmosphere surrounding the leaf. 



Several determinations of the ratio of 
the increase in carbon content of the illu- 
minated leaf to the increase in dry weight 
yielded a value for the percentage of car- 
bon in the photosynthate of 41.38 ± 0.60 
per cent. This value clearly approximates 
the percentage of carbon in a disaccharide 
(cane sugar, for example, contains 42.10 
per cent carbon) and suggests that the 
photosynthate may be carbohydrate alone. 
However, the carbon content of the dried 
sunflower leaves used as controls for the 
photosynthesis experiments was 45.74 ± 
0.24 per cent. On an ash-free basis this cor- 
responds to a carbon content of 51 or 
52 per cent for the organic material of the 
leaf. This value is considerably higher 
than the carbon content of the photosyn- 
thate, or even of cellulose (44.4 per cent), 
and indicates that subsequent metabolic 
processes of the leaf may transform the 
organic matter formed during the photo- 
synthesis into a more highly reduced state. 

Direct analysis has shown that the or- 
ganic matter formed by the sunflower leaf 
during a short period of illumination 
(about 60 minutes) consists largely of car- 
bohydrates, 91.87 ± 1.46 per cent. By suit- 
able analytical procedures these carbohy- 
drates can be separated into several frac- 
tions. The percentage of the assimilated 
carbon attributable to each of these frac- 
tions is as follows: 

Fraction Percentage 

Glucose + levulose 9.98 

Sucrose 5!-9 2 

Unidentified sugar 3.12 

Unidentified polysaccharide. . 1.38 
Starch 2 549 

In these experiments the leaves, after re- 
moval of the midrib, were quartered and al- 
ternate quarters used as control and as pho- 
tosynthesizing agent. Quartering rather 
than halving insured a greater similarity 



124 



CARNEGIE INSTITUTION OF WASHINGTON 



of the two leaf portions. Removal of the 
midrib avoided the loss of organic material 
by transport but deprived the leaf of ex- 
ternal water supply, with consequent water 
deficit. This may have altered the normal 
ratios of the carbohydrates to one another. 

The residue from the illuminated por- 
tion of the leaf, after removal of all solu- 
ble material, contained a portion of the 
photosynthate. It is not known whether 
this part of the photosynthate consisted 
of carbohydrate (cellulose, hemicellulose, 
etc.) or of protein, but nitrogen analyses 
indicated that possibly a part of it might 
be protein. At the present stage of the 
investigation, values for the carbon con- 
tent of this portion of the photosynthate 
must be assumed. Calculations based on 
the percentage of carbon in cellulose and 
in protein would assign to this portion 
of the photosynthate 6.49 and 7.61 per 
cent, respectively, of the total increase in 
content of carbon. The total recovery of 
carbon would be then either 98.36 or 99.48 
per cent, with a probable error of about 
±3 per cent. 

In the experiments just described, the 
leaves photosynthesized for about an hour 
and respired for an additional 20 minutes 
before being killed. During this time 
respiration and other nonphotosynthetic 
transformations of carbohydrates undoubt- 
edly occurred. These transformations may 
have caused the recovery of carbohydrate 
to be less than the amount actually formed 
by photosynthesis, and an attempt was 
made to determine whether or not this was 
so. For this purpose the percentage re- 
covery of assimilated carbon in the form 
of carbohydrates was determined after a 
4-hour dark period immediately following 
a period of photosynthesis. In some in- 
stances, during the prolonged respiration, 
a much greater loss of carbohydrates took 
place than was attributable to respiration 
as measured by carbon dioxide liberation. 



This suggests that a rapid synthesis of 
other substances takes place from carbo- 
hydrates and accounts in certain experi- 
ments for the exceedingly low recovery in 
the form of carbohydrates. In other cases 
the liberation of carbon dioxide from the 
leaf exceeded the loss of carbohydrates, 
and a recovery of an apparent excess of car- 
bohydrates resulted. Whether part of this 
excess arose from an additional synthesis 
of sugar in the dark is not known. The 
results of these experiments were too in- 
consistent to justify generalization, but 
they were sufficiently clear to explain the 
variations in the recovery values of car- 
bohydrates. The factors influencing these 
changes are still beyond our knowledge. 

The results of these experiments show 
that the preponderant products of the 
photosynthetic activity of sunflower leaves 
are carbohydrates, and that if other sub- 
stances are formed they constitute only a 
small part of the photosynthate. 

Although these experiments demonstrate 
that photosynthesis by sunflower leaves 
may produce a quantity of carbohydrate 
equivalent to the quantity of carbon di- 
oxide absorbed, the carbohydrates formed 
may or may not incorporate the same car- 
bon atoms as are absorbed. It is conceiv- 
able that the assimilation of carbon diox- 
ide may initiate a chain of reactions which 
culminates in a quantitative yield of car- 
bohydrates without incorporating into 
these carbohydrates the particular carbon 
atoms absorbed. The present experimen- 
tal methods are ill suited to distinguish 
between these two possibilities, direct and 
indirect formation of carbohydrates, but 
by the use of labeled carbon such a dis- 
tinction should be possible. 

Because of war conditions this tracer ele- 
ment has not been available. It may be 
feasible to prepare radioactive carbon, C 14 , 
by means of the Stanford cyclotron, and 
experiments are now under way, in which 



DIVISION OF PLANT BIOLOGY 



125 



the Department of Physics of Stanford 
University is generously cooperating, for 
the purpose of examining this possibility. 

Plant Polyuronides 

Although polyuronides such as hemi- 
celluloses, gums, mucilages, and pectin are 
widespread and constitute a very appreci- 
able part of the framework of higher 
plants, virtually nothing is known regard- 
ing the mode of formation of these sub- 
stances. There has been some indication 
that they may be derived from starch 
through a series of steps involving the 
oxidation of the primary alcohol groups 
with the formation of uronic acid units. 
An effort has been made by Dr. Spoehr 
and Mr. Milner to determine whether the 
primary alcohol groups of starch can be 
oxidized in vitro to form substances con- 
taining uronic acids. 

The most promising oxidizing agent 
was found to be hydrogen peroxide in 
the presence of a small amount of ferrous 
sulfate. With this reagent the starch was 
readily oxidized at 20 ° C. and was simul- 
taneously hydrolyzed. By treatment with 
boiling 12 per cent hydrochloric acid poly- 
uronides are decarboxylated and yield 25 
per cent of carbon dioxide and appreciable 
amounts of furfuraldehyde. In a series 
of oxidations of starch, using 1 to 8 mols 
of hydrogen peroxide per glucose unit, 
the oxidation product giving the highest 
yield of carbon dioxide by the method just 
mentioned was obtained with about 5 mols 
of hydrogen peroxide. This yield of car- 
bon dioxide amounted to 22.56 to 25.20 
per cent in various preparations. This oxi- 
dation product proved, however, not to 
be a uronic acid, as it did not give the 
characteristic reaction with naphthoresorci- 
nol, and yielded but small quantities of 
furfuraldehyde. As by-products in this oxi- 
dation, carbon dioxide, formic acid, and 
oxalic acid are also formed, increasing in 



quantity with the use of larger amounts of 
the oxidizing agent. 

The oxidation product obtained with 
5 mols of hydrogen peroxide is very solu- 
ble in water, methanol, and ethanol, and 
insoluble in ether, acetone, and nonpolar 
solvents. Unfortunately it could not be 
crystallized. Neither could well denned 
metal or alkaloid salts be obtained, nor 
definite compounds with phenylhydrazine, 
its substituted derivatives, or other organic 
compounds. This is apparently due to the 
fact that the oxidation product is very 
easily decarboxylated. In water solution it 
loses carbon dioxide slowly at room tem- 
perature, loses it more rapidly at 50 C, 
and at ioo° yields about 18 per cent; this 
is to be compared with a yield of 24 per 
cent carbon dioxide by treatment with 12 
per cent hydrochloric acid. A water solu- 
tion of the oxidation product when treated 
with brucine, strychnine, pyridine, phenyl- 
hydrazine, aniline, o-phenylenediamine, or 
o-toluidine rapidly liberated 3 to 5 per 
cent carbon dioxide. 

When exposed to light in the presence 
of air, a water solution of the oxidation 
product yields large amounts of carbon 
dioxide. At 20 ° C. about 75 per cent of 
the substance is thus oxidized to carbon 
dioxide in 32 hours, the photooxidation 
proceeding approximately linearly with 
time. The oxidation product has strong 
reducing properties; it reduces silver ni- 
trate in the cold, also potassium perman- 
ganate, iodine, Benedict solution, and so- 
dium 2,6-dichlorobenzenoneindophenol. It 
showed no vitamin C properties when 
tested on guinea pigs. 

A molecular weight of 306 was obtained 
by the cryoscopic method in water solution, 
and although the electrometric titration 
curve was of indefinite shape, an equiva- 
lent weight of 140-150 was obtained, indi- 
cating a dicarboxylic acid. In view of the 
fact that it loses 2 mols of carbon dioxide 



126 



CARNEGIE INSTITUTION OF WASHINGTON 



when treated with 12 per cent hydrochloric 
acid and that at least half of this carbon 
dioxide is lost with great ease, the sub- 
stance is probably in part a (3-keto acid. 
Combustion analysis gave results agree- 
ing well with the empirical formula 
C1.0H12O12. 

Both glucose and maltose were oxidized 
with the same oxidizing agent. With 3 
mols of hydrogen peroxide, in compari- 
son with starch, glucose yielded about 8 
times as much formic acid, very little ox- 
alic acid, and a main oxidation product 
which yielded only 10 per cent of carbon 
dioxide when treated with 12 per cent 
hydrochloric acid. Maltose, on the other 
hand, when oxidized with 8.4 mols of 
hydrogen peroxide (equivalent to 4.2 mols 
per glucose unit), yielded, besides small 
amounts of formic and oxalic acids, a 
main oxidation product having the same 
properties and yielding the same percent- 
age of carbon dioxide on decarboxylation 
as the product obtained from starch. The 
molecular weight of the oxidation product 
obtained from maltose was also very nearly 
the same as the value obtained for the 
starch oxidation product, and the combus- 



tion analyses of the two substances were 
in close agreement. 

These findings may prove to have some 
bearing on the constitution of the starch 
molecule, a problem which has occupied 
chemists for many years. The enzymatic 
hydrolysis of starch yields maltose, whereas 
hydrolysis with acids usually yields glucose. 
When starch is treated with hydrogen 
peroxide in the presence of small amounts 
of iron, the main product formed repre- 
sents a molecule which is larger than could 
arise from the oxidation of glucose. This 
indicates that with this reagent the starch 
in the course of oxidation splits into units 
of more than six carbon atoms. Although 
it is impossible to determine at what stage 
of the oxidation splitting of the starch 
molecule occurs, the fact that the same 
product is obtained from starch and malt- 
ose indicates that the oxidation product 
of starch is derived from a maltose unit. 
Evidence obtained thus far does not war- 
rant assigning a structural formula to the 
oxidation product obtained from starch, 
although several C10H12O12 formulas can 
be written which are consistent with the 
observed properties. 



EXPERIMENTAL TAXONOMY 

Jens Clausen, David D. Keck, William M. Hiesey, and E. V. Martin 



Fundamental to our understanding of 
plant relationships is knowledge concern- 
ing the make-up of climatic races of the 
same or of closely related wild species. 
In climatic races we can study evolutionary 
divergence in its early stages, and then 
progress to differences of greater order 
such as are found in species and genera. 
An understanding of the principles that 
govern the distribution of such races is 
basic not only to an understanding of evo- 
lution, but also to successful plant breed- 
ing, because cultivated plants, like wild 
ones, are healthier and more productive 



when they fit the environment in which 
they are grown. During the past year con- 
siderable progress has been made in the 
study of genetic variations of natural pop- 
ulations of Achillea and Potentilla glandu- 
losa. 

The general organization of plant groups 
into recognizable units of successively 
higher order as disclosed by experimental 
means has already been outlined (Year 
Book No. 39, pp. 158-163, and No. 40, 
pp. 160-170). Such categories include local 
populations, climatic races, species, species 
complexes, and genera. The relations be- 



DIVISION OF PLANT BIOLOGY 



127 



tween the higher categories have been 
most effectively studied in the annual spe- 
cies of the Madiinae and will be the sub- 
ject of publications now in preparation. 
For the study of the lower categories, such 
as the climatic races or ecotypes within 
one species, perennials such as Achillea 
and Potentilla are more suitable because 
their species range over several climatic 
zones and have evolved a much richer 
array of races. From the appearance of 
plants in the wild, one would conclude that 
Achillea has evolved series of continuously 
intergrading races in certain areas. 

Hereditary Composition of Climatic 
Races 

Basic to the whole idea of evolution by 
natural selection is individual variability. 
Modern genetics has been built upon the 
study of the inheritance of individual 
differences so distinct that they can be 
readily separated and classified — the so- 
called mutants. The neo-Darwinian theo- 
ries of natural selection are based mainly 
on facts known about such characters. 
Although the mutants analyzed in labora- 
tory experiments are indispensable for the 
study of the laws governing inheritance in 
general, their survival value in natural se- 
lection is very questionable. Therefore, 
before results from laboratory experiments 
can be utilized in explaining evolution, 
they need to be corroborated by studies on 
characters typical of wild plants. 

After extensive studies on the cytoge- 
netics of wild populations, it appears that 
the theories of evolution by mutation and 
recombination have generally been over- 
simplified. This becomes evident when 
contrasting climatic races of a species are 
crossed, and the hybrid segregants of the 
second and third generation are studied. 
Climatic races differ by many characters, 
and the segregations indicate that even 
small morphological differences are deter- 



mined not by one, but by several pairs of 
genes, each changing the individual 
slightly. The effect of the individual gene 
in wild races is therefore less upsetting 
to existing gene balances, but also less 
distinct in expression, than that of genes 
utilized in orthodox genetic experiments. 

The number of genes determining each 
character is limited, however. It has been 
found, for example, that differences in 
habit, mode of branching, earliness of 
flowering, color of flowers, shape of seeds, 
and other characters found between cli- 
matic races are frequently governed by no 
more than three or four pairs of genes. 
In some races the genes for different char- 
acters may show linkage, in others not. 
The important fact is that the inheritance 
of these characters is neither very simple 
nor so complex that small but discontinu- 
ous steps of evolution, such as are postu- 
lated by classic genetic theory, are ruled 
out. 

Seedlings of wild populations of both 
Achillea and Potentilla glandulosa from 
many points in the Coast Ranges and from 
approximately 1000-foot altitudinal inter- 
vals along our Sierra Nevada station tran- 
sect are being grown at Stanford for care- 
ful comparative study. Seedling cultures 
of Achillea attain maturity within two 
years, but the Potentillas require an extra 
year for their full development and the 
first of them are just now beginning to 
manifest their characteristic differences in 
the Stanford garden. 

As previously pointed out (Carnegie 
Inst. Wash. Pub. 520, pp. 296-300), the 
climatic races of Achillea in California be- 
long to two species which apparently do 
not overlap, but together cover the entire 
transect from the coast to the desert 
plateaus. At latitude 38 ° north, Achillea 
borealis, with 27 pairs of chromosomes, 
covers the distance from the coast to the 
Sierran foothills, and the 18-chromosome 



128 



CARNEGIE INSTITUTION OF WASHINGTON 



A. lanulosa extends from the lower bor- Alaska, and lanulosa eastward to the Great 
ders of the Transition zone, at 3000 feet Plains over a great altitudinal and climatic 
in the Sierra Nevada, to above tree line range. 

STEM-HEIGHT FREQUENCIES IN ACHILLEA RACES AT STANFORD 



Specie 


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PROFILE ACROSS CALIFORNIA NEAR LATITUDE 38° N. 
Fig. i. An analysis of climatic races of Achillea assembled in a uniform garden. See text. 

at 11,000 feet and down the eastern flank An illustration of how characters in gen- 

to the Great Basin. Both species contain eral may vary is given in figure i, which 

contrasting climatic races. Achillea bore- shows the variation in height of flowering 

alis extends northward along the coast to stems of eighteen populations of Achillea 



DIVISION OF PLANT BIOLOGY 



129 



from this transect. These were grown in a 
uniform garden at Stanford. The class 
frequencies for 10-centimeter intervals of 
plant height are given in the vertical col- 
umns, all but two of the populations con- 
sisting of approximately 60 individuals 
each. The curve passes through the mean 
height of each population, which is indi- 
cated by the scale at the sides of the 
graph. The geographical location from 
which the seeds for each population were 
taken is shown in relation to the profile of 
a transect across California below. The 
horizontal distances in the graph approxi- 
mate functions of the topography of the 
cross section of California, starting at the 
Pacific to the left. The dominating in- 
fluence in the left-hand part of the figure 
is the increasing distance from the sea, 
whereas in the right half the dominating 
influence is the increase in altitude of the 
habitats. The headings of the figure indi- 
cate the limits between the two species, and 
the climatic races represented. Although 
the sampling is more intensive than in the 
transplant experiments, each major race 
is represented by a minimum number of 
populations. 

The extreme maritime race of Achillea 
borealis clings to the wind-swept, fog- 
laden, narrow strip of coast overlooking 
the ocean. Its genetically low habit is 
probably a selective response to the prevail- 
ing strong winds. The population from 
the Bodega coast north of San Francisco 
Bay is the most extreme of those illus- 
trated, but an even more extreme form oc- 
curs 350 miles farther north on the bluffs 
near Port Orford, Oregon. The most mari- 
time forms are low and spreading, with 
massive, thick-textured, dark-green rosette 
leaves, and late flowering such as is typical 
of maritime ecotypes of other species. In 
populations from somewhat less wind-ex- 
posed coasts, such as the dunes and bluffs 
of San Francisco and the coast at Montara, 



the selection appears to have been less 
rigid. Although some individuals as ex- 
treme in appearance as those from the 
Bodega coast and Port Orford occur here, 
a slightly taller and earlier form is more 
common. This, however, has the charac- 
teristic maritime type of leaf. 

As one moves inland from the windy 
coast, the maritime race is rapidly replaced 
by that of the outer Coast Ranges, a very 
tall but still fairly late-flowering form, 
which appears able to make maximum use 
of the abundant moisture in the coastal 
fog belt. The San Gregorio population 
in figure 1 is typical of this race. There is 
hardly any overlapping in height at Stan- 
ford between plants of this population and 
those from the most exposed coasts such as 
Bodega, but its smaller plants are a match 
for the taller ones from less exposed shores 
such as those of Montara and San Fran- 
cisco. The leaves of the outer Coast Range 
race, however, generally have much less 
dense segments than those of the maritime 
race. 

The maritime and outer Coast Range 
races meet a very short distance from the 
sea. The populations at these localities con- 
tain mixtures and recombinations of the 
two races. This is illustrated by the two 
populations from the base of Montara 
Mountain, a locality approximately l / 2 mile 
from the sea. One population was ob- 
tained by sowing seed gathered from 
plants of low stature only, and the other 
was derived from seed collected from tall 
individuals. When grown at Stanford, 
the two populations differed significantly 
in height, as can be seen in the figure. 
Moreover, the offspring from the short 
plants corresponded to the maritime race, 
whereas those from the tall ones resembled 
plants of the outer Coast Range race. 

In the Upper Sonoran zone of limited 
rainfall around the valleys of the inner 
Coast Ranges and in the Sierran foothills 



^o 



CARNEGIE INSTITUTION OF WASHINGTON 



another recognizable race occurs. It flow- 
ers months earlier than the maritime 
forms, while there is still adequate mois- 
ture from early spring rains, and then 
dries up, becoming dormant during the 
summer and fall period. This is in con- 
trast with the maritime race, which is ever- 
green when grown at Stanford, and also 
in contrast with the outer Coast Range 
race, which is intermediate between the 
maritime and foothill forms in earliness 
and dormancy. The three populations of 
the inner Coast Range and foothill race 
indicated in figure i are also distinguished 
from the maritime by their grayer pubes- 
cence and few rosette leaves. Each of these 
populations shows an appreciable amount 
of individual variability, the Colusa 
County population including individuals 
approaching those found in the outer Coast 
Ranges. 

A giant form of Achillea borealis occurs 
in the Lower Sonoran zone in limited 
areas along streamways on the hot San 
Joaquin Valley floor. A population of this 
strain, which is early and in its native 
habitat reaches a height of 2 meters, has 
recently been acquired, but is too im- 
mature at this writing to be included in 
the tabulation. 

In passing to elevations of 3000 feet in 
the Sierra Nevada, as at Groveland, where 
the ponderosa pine and incense cedar re- 
place digger pine and blue oak, one en- 
counters the Transition zone race of an- 
other species, the 18-chromosome Achillea 
lanulosa. Populations of this species up 
to 5000 feet closely resemble the foothill 
forms of Achillea borealis, although the 
cytological difference between them pre- 
vents free exchange of genes through 
crossing. Plants of the Transition zone 
race can be distinguished from the foot- 
hill race principally by chromosome num- 
ber and by their much later flowering 



when grown at Stanford. Also, they usu- 
ally have smaller heads and more slender 
stems and remain green later in the 
summer. 

All the climatic races of Achillea bore- 
alis indicated in figure 1, and also plants 
of the Transition zone race of A. lanulosa 
from lower elevations, remain green and 
active at Stanford during the winter. From 
higher elevations in the Transition zone 
upward, the plants show an increasing de- 
gree of winter dormancy and a lowering of 
stature at Stanford. 

In populations from the Transition zone, 
a mixture of winter-green and winter-dor- 
mant plants is found, as well as individual 
variation in height. This has been ob- 
served, for example, in the Mather and 
Hetch Hetchy Road populations. At ap- 
proximately 6000 feet altitude in the Ca- 
nadian life zone, characterized by red fir 
and Jeffrey pine, the transformation from 
winter-green to winter-dormant plants is 
almost completed, and one encounters a 
climatic race that at Stanford attains a 
mean height approximately 25 centimeters 
less than that of the populations from the 
Transition zone. The Canadian zone race, 
exemplified by the Aspen Valley popula- 
tion, goes dormant during the winter at 
Stanford and is generally late and very 
erratic in its flowering. However, single 
plants comparable with those typical of 
the Transition zone are found mixed with 
the others, just as one finds mixed stands 
of Jeffrey and ponderosa pine. Near the 
upper edge of this zone there is consider- 
able intermixing of this race with the sub- 
alpine race above it. For example, the 
variable Yosemite Creek population from 
7200 feet includes plants indistinguishable 
in height, leaf form, pubescence, and time 
of flowering from Tenaya Lake plants of 
the subalpine race at an elevation of 8200 
feet. 



DIVISION OF PLANT BIOLOGY 



131 



At around 8000 feet, in the lodgepole 
pine belt, the stems of Achillea are much 
shorter and more slender, and have more 
contracted inflorescences. Most conspicu- 
ously, the leaves are grayer-pubescent, 
much smaller, and proportionately much 
narrower. This trend continues to the up- 
per limit of the species distribution at 
11,000 feet. Parallel with these morpho- 
logical differences is a lengthening of the 
dormancy period during the winter at 
Stanford, as compared with that of the 
plants of the Canadian zone. Taxonomi- 
cally these subalpine and alpine forms are 
known as subspecies alpicola. 

It appears that this high-montane sub- 
species is composed of more than one 
climatic race, a subalpine and an alpine. 
Figure 1 shows that there is a distinct 
difference in height and ability to flower 
at Stanford between the plants from Te- 
naya Lake, on the one hand, and those 
from Tuolumne Meadows and Slate Creek 
Valley on the other. This is also empha- 
sized by differences in earliness of flower- 
ing, especially as observed on transplants 
at our alpine station in Slate Creek Val- 
ley. Both the subalpine and alpine races 
are erratic in their flowering at Stanford, 
an evidence of their being out of harmony 
with this environment. Some plants are 
extremely early, others very late, and more 
than 50 per cent of the plants of the most 
alpine population are unable to produce 
flowering stems at all. Also, the number 
of stems is very small in plants from 
high altitudes as compared with those from 
lower altitudes. 

Each population from these higher alti- 
tudes contains a few individuals typical 
of the neighboring climatic race. A few 
characteristically alpine plants were found 
in the Tenaya Lake population, and a few 
of subalpine reaction from Tuolumne 
Meadows and Slate Creek Valley, but 



more than 80 per cent of the individuals 
in each population were characteristic of 
the climatic race to which they were 
assigned. 

At the uppermost limit of the range of 
Achillea lanalosa, 11,000 feet, the most 
dwarf, most pubescent, and apparently 
most uniform race of all is encountered, 
but transplants from this altitude are at 
the present writing too immature for 
study. The apparent uniformity of this ex- 
treme alpine recalls the relative homo- 
geneity of the extreme maritime popula- 
tion of A. borealis from the Bodega coast, 
and suggests that at these extremes natu- 
ral selection has been more rigid and the 
influx of genes from other racial elements 
more limited. 

Finally, in the Great Basin, at 6000 to 
8000 feet elevation, forms occur that are 
genetically taller than the alpines and 
among the most frost-resistant of all Achil- 
leas. Plants of this race have been observed 
at the alpine station in early bloom and 
apparently undamaged after temperatures 
as low as — 10 ° C, when other races were 
badly frozen. It is obvious that frost-hardi- 
ness is a desirable character for a plant 
native to the interior plateaus which have 
severe winter temperatures but very little 
snow cover. Cultures of this climatic race 
are still too immature to be included in 
the tabulations. 

In summary, we find that the climatic 
races of Achillea reflect the changes in 
climate associated with the topography of 
California to a remarkable degree. Each 
major climatic belt has its climatic race 
of Achillea, of characteristic appearance 
and reaction. In gross features, the dis- 
tribution of the climatic races appears to 
follow that of the characteristic trees and 
other indicator plants of the different life 
zones, although the agreement is not 
absolute. 



132 



CARNEGIE INSTITUTION OF WASHINGTON 



No natural population of Achillea is 
uniform, but apparently each has sufficient 
variability and genes to provide for a 
considerable array of forms in any one en- 
vironment. Some of this variability is 
evidently physiological. Judging from the 
reactions observed in the Stanford garden, 
this variability usually appears large 
enough to include a few individuals char- 
acteristic of the neighboring climatic races. 
Possibly more individual variability can be 
observed in the garden than in nature 
because of the elimination that takes place 
under natural competition. The variability 
demonstrated to occur in wild populations, 
however, suggests a range of physiological 
tolerance which, by genie recombination, 
may give rise to new populations success- 
ful in other habitats. 

There is considerable evidence that for- 
est trees and grasses have climatic races 
similar to those observed in Achillea and 
Potentilla. Several years' data have been 
gathered on the climatic races of the tufted 
hair grass, Deschampsia caespitosa. This 
species, like Achillea, occurs throughout 
the northern hemisphere. A few races 
from Scandinavia, from arctic Lapland, 
and from a transect across California from 
the coast to 10,000 feet altitude in the 
Sierra Nevada are being grown at the 
transplant stations. In this species the 
races native to the California mountains 
are constantly being exterminated by rust 
at Stanford, although they are not attacked 
in their native habitats. Though the other 
races succeed at this station, the loss of 
the mountain races here is a handicap in 
the investigations. These observations and 
those on other plants suggest that the 
problem of resistance to diseases may be 
closely allied to the fitness of a plant for 
the climate in which it is being grown. 
This point of view might find valuable ap- 



plication in the breeding of disease-resist- 
ant crop plants. 

Physiological Studies 

The knowledge that has been gained 
concerning the nature of climatic races 
makes it possible to formulate a program 
of investigation on their functional differ- 
ences. Relatively simple methods for com- 
paring basic physiological functions of 
climatic races give promise of making it 
possible to relate the physiological reactions 
characteristic of climatic races to the ability 
of the races to survive in different en- 
vironments. 

The general method of approach will be 
to compare the effects of one environ- 
mental variable on several selected func- 
tions of contrasting climatic races under 
controlled conditions. Two types of experi- 
ment are planned : one is to be exploratory 
and qualitative, and the other is to be 
controlled and quantitative. The object 
of the exploratory experiments is to deter- 
mine the general limits within which it 
may be profitable to conduct the more 
precise work. The quantitative experi- 
ments will be conducted in chambers in 
which radiation, temperature, and relative 
humidity are regulated, so that these con- 
ditions may be changed or closely repro- 
duced at will. 

In the study of altitudinal and latitudinal 
races, it is assumed that the principal con- 
trolling environmental factor is tempera- 
ture. This assumption is made because of 
the great similarity in the nature of the 
variation between the two kinds of races, 
and because temperature is the outstanding 
variable common to both series. It is prob- 
able that other factors may also be im- 
portant, but it is felt that the effects of 
temperature should be thoroughly investi- 
gated first. The functions to be studied are 
assimilation, respiration, and absorption of 



DIVISION OF PLANT BIOLOGY 



133 



water by roots. Water absorbed by roots 
will be measured volumetrically as it is 
removed from culture solutions. By meas- 
uring carbon dioxide exchange and rate 
of water uptake simultaneously, possible 
correlations between these functions may 
be studied. 

The most contrasting altitudinal races 
of a species will be compared first; inter- 
mediate races may be introduced later on. 
Genetically different individuals of one 
population may also differ in their physio- 
logical activity over a range of tempera- 
tures, and possibly even in their tolerance 
to extreme temperatures. It is hoped that 
such data will reveal the physiological 
differences on which the evolution and 
existence of climatic races seem to depend. 

The exploratory type of physiological 
experiment has been initiated by the con- 
struction of an apparatus designed to pro- 
vide a gradient in soil temperatures for 
studies on the effect of this factor upon 
growth of climatic races of Achillea and 
Potentilla glandulosa. This apparatus con- 
sists of a sand-filled tank, well insulated 
and fitted with an insulating lid with holes 
for the plants. At each end of the tank 
is a compartment in which the tempera- 
ture is maintained at a constant value. 
One end is kept near o° C. by means of a 
refrigerating compressor; the other is kept 
near 40 ° C. by electric heaters. Both tem- 
peratures are kept nearly constant by ther- 
moregulators. A gradient of temperature 
through the sand is established by the pres- 
ence of these end compartments. The 
sand-filled part is partitioned into smaller 
units in order to restrict the roots to a 
fairly narrow range of temperature. The 
sand is watered from below with nutrient 
solution by a hydrostatic system. 

Seedlings or rooted cuttings of altitu- 
dinal races are grown in rows running 
the length of the tank from the warm to 



the cold end. The apparatus is located 
in a small greenhouse in a place where the 
aerial parts of the plants are exposed to as 
nearly the same environment as possible. 
In this manner, relations between soil tem- 
perature and growth of roots of the vari- 
ous climatic races are being studied in con- 
nection with the growth of tops in a given 
aerial environment. 

An apparatus for experiments of a quan- 
titative nature has been designed and 
partly constructed. It consists essentially of 
a cubical air chamber 14 inches on each 
side, in which air temperature, relative 
humidity, and radiation intensity are to be 
controlled. It is designed to maintain air 
temperature constant at any value between 
0° C. and 50 C, relative humidity be- 
tween 20 and 80 per cent, and radiation 
between zero and half or more of full sun- 
light intensity. Two sides and the top of 
the chamber are of glass to permit entrance 
of radiation from lamps. 

The container holding the roots projects 
through the floor of the chamber into a 
solution the temperature of which can be 
controlled independently of that of the air 
around the shoots. The air system is to 
be made airtight so that changes in con- 
centration of carbon dioxide may be meas- 
ured. 

Individuals of races for use in these ex- 
periments will be grown in nutrient solu- 
tion in a greenhouse. After being thus ex- 
posed to closely similar environmental con- 
ditions, these will then be introduced into 
the control chamber for a study of their 
physiological functions. 

It is hoped that in the future these in- 
vestigations may be extended to the study 
of growth of climatic races under condi- 
tions which will permit control of all fac- 
tors of the environment during their entire 
life cycle. It will then be possible to in- 
vestigate the carbon dioxide exchange and 



134 



CARNEGIE INSTITUTION OF WASHINGTON 



water absorption of plants grown under 
a wide range of reproducible environmen- 
tal conditions. The development of the 
control chamber is temporarily suspended 
because Dr. Martin, who designed and 
was building it, is now engaged in war 
research. 

Investigations on the Madiinae 

Efforts of the staff are being concen- 
trated on the analysis of many years' ac- 
cumulated data on Layia and related gen- 
era, and on the completion of experi- 
mental work needed to round out the in- 
vestigations on the other Madiinae. The 
results on the Layia group are being pre- 
pared for publication. 

The investigations on Layia were dis- 
cussed rather fully in Year Book No. 40, 
pages 160-170. Developments in the study 
of the genus during the past year include 
the completion of genetic analyses of pap- 
pus characters in geographical strains of 
Layia platyglossa, data from F2 popula- 
tions of hybrids in the Layia gaillardioides 
group, and the establishment of the ge- 
netic relationship of a newly discovered 
Layia whose morphology is so unlike that 
of other members of the genus that even 
its inclusion in the subtribe Madiinae was 
open to question (cf. Year Book No. 40, 
p. 168). From hybrids now obtained it 
appears that this plant is probably a mere 
subspecies of Layia glandulosa, with which 
it seems to be highly interfertile. It is 
apparently an extremely reduced and slen- 
der form of that species, with ray florets 
completely lost and the pappus much ab- 
breviated. 

The newly synthesized Madia citrigraci- 
lis, mentioned in the previous report, is 
being grown in its third generation for 
further tests on its fertility and cytological 
regularity, and for comparisons with its 
parent species, Madia gracilis and M. citri- 
odora, as well as with the native citrigraci- 
lis obtained in the wild. 



Miss Marguerite E. Hartung, formerly 
of the University of Hawaii, has been en- 
gaged during the current year in micro- 
technical work in connection with cyto- 
logical studies on the Madiinae, and has 
aided in the analyses of hybrid popula- 
tions of Layia and Madia. She succeeds 
Mr. Malcolm Nobs, who now is in the 
United States Army. Exploratory studies 
by Mr. Nobs on the cytogenetics of the 
wild lilacs of California, the genus Cea- 
nothas, have been incorporated in a re- 
cently published monograph on this com- 
plex group by Professor Howard E. Mc- 
Minn, of Mills College. 

Studies at the Transplant Stations 

Final data are being obtained this year 
on the selection experiment involving an 
F 2 hybrid population between a foothill 
and an alpine form of Potentilla glandu- 
losa (cf. Year Book No. 39, p. 162). These 
will be subjected to a thorough analysis 
before publication. 

New clone transplants consisting of 30 
individuals each of fourteen populations of 
Achillea have been set at the Stanford, 
Mather, and Timberline transplant stations 
this year. These populations are from 
altitudinal intervals of approximately 1000 
feet along the station transect, with a strain 
from the Danish seacoast and another from 
Lapland included. All these transplants 
are to be studied with special reference to 
genetic variation within populations and 
to differences between populations as a 
whole in these contrasting environments. 
It is intended to coordinate these studies 
closely with the physiological investiga- 
tions in the hope that a clear picture may 
be obtained of the interrelations between 
genetic variation in natural populations 
and climatic races on the one hand and 
physiological functions on the other. This 
should lead us to a clearer understanding 
of the dynamics of evolution. 



DIVISION OF PLANT BIOLOGY 



135 



DESERT INVESTIGATIONS 

Forrest Shreve 



In previous years the investigation of the 
Sonoran and Chihuahuan deserts has con- 
sisted almost entirely in work on the vege- 
tation and in the effort to secure a com- 
plete enumeration of the vascular plants. 
The core of these projects, however, is a 
knowledge of the influences of climate and 
soil in determining the vegetational and 
noristic features that have been found. 
Practical considerations have made it im- 
possible to attempt an adequate system 
of instrumentation over such large areas 
or even to carry on a restricted system for 
more than a few years. Official American 
and Mexican climatic data are very help- 
ful, although they are lacking in regard to 
many phases of great biological impor- 
tance. Also, desert climatological stations, 
like all others, are located at centers of 
population rather than at critical places 
in the climatic map. Many of the data ob- 
tained at the Desert Laboratory over long 
periods are of biological significance, but 
they are not all applicable to other parts 
of the desert. 

Work on the vegetation and flora of the 
desert areas has been continued, and dur- 
ing the past year an appraisal has been 
made of all data bearing on the physical 
conditions of the Sonoran and Chihuahuan 
deserts. A detailed study of the data has 
been completed for the rainfall only. 

Field Work 

In the summer of 1941 Dr. Shreve con- 
tinued the exploration of the eastern edge 
of the Chihuahuan Desert and examined 
the elevated plateau of Hidalgo and east- 
ern Queretaro. The principal objective 
was to learn the character of the Hidalgan 
desert and the relation between the north- 
ern and southern types of desert in Mexico. 



The northern type, characteristic of the 
lower elevations of Chihuahua and Coa- 
huila, does not extend south of the state of 
San Luis Potosi. Much of the desert of 
Hidalgo is edaphic rather than climatic. 
On extensive areas of shallow limestone 
soil, the vegetation is desert, and similar 
to that of central San Luis Potosi. On deep 
and retentive volcanic soils at the same al- 
titude, the vegetation is arid bushland 
of a type which bounds the desert at many 
places along its eastern and southern edges. 
Where streams or abrupt canyons are 
found in the arid highlands of Hidalgo, 
the vegetation is closely related to the 
northern fringe of tropical forest common 
in northern Veracruz, and has no relation 
to the vegetation of similar habitats in the 
desert. Also the floristic relationship of the 
moister habitats is preponderantly with the 
subtropical lowlands rather than with the 
desert. Locating the southern limit of the 
Chihuahuan-Coahuilan type of desert has 
been made difficult by the recurrence of 
desert valleys separated by hilly and moun- 
tainous areas of bushland or forest. Suf- 
ficient study of the region has now been 
made, however, to warrant a definite de- 
limitation of the southern boundary of the 
Chihuahuan Desert in central San Luis 
Potosi. 

Proximity to Mexico City gave an op- 
portunity to visit the Biological Institute 
of the National University of Mexico, from 
which have emanated several important 
investigations of the vegetation of central 
and southern Mexico. Dr. Isaac Ochote- 
rena, Director of the Institute, has long 
been very helpful, both officially and scien- 
tifically, in connection with our work in his 
country. Discussions with him and with 
Dr. P. F. Villagran and Professor L. An- 



136 



CARNEGIE INSTITUTION OF WASHINGTON 



cona, o£ his staff, were full of valuable 
comments and suggestions, and were par- 
ticularly helpful with reference to the 
status of the arid regions of Puebla and 
Oaxaca. 

Visits were also made to the National 
Meteorological Observatory of Mexico, at 
Tacubaya. Through the courtesy of Sr. 
Jose C. Gomez, Chief of the Meteorologi- 
cal Service, we were supplied with a com- 
plete transcript of the rainfall and tem- 
perature data for all the older stations in 
the Sonoran and Chihuahuan deserts. This 
material is invaluable in a study of the 
environmental conditions of the desert 
regions. 

Dr. I. M. Johnston spent 10 weeks in 
the field in central Coahuila and eastern 
Chihuahua in the past summer, accom- 
panied by Dr. Kirk Bryan, of Harvard 
University, who was engaged in physio- 
graphic investigations in the same area. 
The desert basins and low mountains ly- 
ing between Musquiz and Cuatro Cie- 
negas, Coahuila, were explored, and also 
the region surrounding Sierra Mojada and 
the Lago de Coyote, lying partly in Coa- 
huila and partly in Chihuahua. A collec- 
tion of over 2000 herbarium specimens was 
made, illustrating fully the distinct floral 
features of the small mountain ranges that 
were visited. 

A plant collection of nearly 2000 num- 
bers was made by Mr. Robert M. Stewart, 
of Santa Elena, Coahuila, and presented 
to Gray Herbarium for study in connec- 
tion with the Chihuahuan Desert project. 
This collection is very useful on account 
of the remote localities in which it was 
taken and because most of the plants were 
obtained in the early and late weeks of the 
summer, periods in which little collect- 
ing has been done in any part of northern 
Mexico. 

A collection made by Mr. Lowden Stan- 
ford and associates, of the University of 



Washington, in the summer of 1941 was 
placed in Dr. Johnston's hands for de- 
termination. This series of 11 00 numbers 
was collected in poorly known hilly and 
mountainous regions in southern Coahuila, 
including the Sierra de Jimulco, the Sierra 
de Parras, and the hills around Fraile, 
Coahuila and Concepcion del Oro, Zaca- 
tecas. This collection from the "cross 
ranges" which traverse the center of the 
Chihuahuan Desert is of considerable 
floristic and ecological interest. 

Dr. Johnston is now preparing for pub- 
lication the descriptions of nearly 100 new 
species that have been detected in the col- 
lections made by himself, Mr. Stewart, 
and Mr. Stanford in the field work of the 
past 2 years. 

Further observations were made by Dr. 
Johnston on the plants confined to out- 
crops of gypsum or soils rich in gypsum, 
and a series of samples for analysis was 
taken in several localities. 

In the summer of 1941 Dr. I. L. Wig- 
gins, accompanied by Dr. Reed C. Rollins, 
visited central Sonora. The aim of the 
trip was to reach the very arid plains and 
hills which lie near the Gulf of California 
between Guaymas and the mouth of the 
Rio Sonora. Part of the region was visited, 
but much of it was found impossible of 
access without more elaborate equipment. 
So many of the plants previously supposed 
to be endemic to the peninsula of Baja 
California have been found in restricted 
localities between Tiburon Island and 
Guaymas that this trackless stretch of des- 
ert coast continues to have an inviting in- 
terest. Dr. Wiggins also visited the foot- 
hills east of Hermosillo and made a col- 
lection of over 500 plants. During his stay 
in the field he took the opportunity to 
give the test of actual use to the keys for 
determination of plants that have been pre- 
pared for the completed parts of his flora 
of the Sonoran Desert. 



DIVISION OF PLANT BIOLOGY 



137 



Environmental Conditions 

In arid regions the character of the rain- 
fall outweighs other physical conditions 
in its influence on the local or habitat dis- 
tribution of plants. It is necessary to con- 
sider several aspects of the rainfall other 
than the annual mean. In fact, this latter 
datum is only of very general importance. 

In a study of the relation of rainfall to 
vegetation in the Sonoran and Chihuahuan 
deserts it has been found desirable to make 
a comprehensive examination of the rec- 
ords for the whole of northern Mexico. 
Only in this way is it possible to under- 
stand the larger storm movements and to 
know about the rainfall conditions just 
outside the desert. The regular annual re- 
currence of storms originating in the Car- 
ibbean Sea and the Pacific Ocean is re- 
sponsible for the seasonal distribution of 
the desert rainfall. The amounts and dis- 
tribution of rain just outside the desert 
represent the minimum requirements for 
other types of vegetation, and in some 
cases are indirectly inimical to desert 
plants. The most arid types of vegetation 
bordering the Sonoran and Chihuahuan 
deserts, excepting other desert areas, are 
the thorn forest of the Pacific coast, the 
grassland and chaparral of Chihuahua and 
Coahuila, and the arid bushland of the 
northeastern coast and the mountains of 
the central plateau. 

From available records it has been pos- 
sible to determine several special features 
of rainfall. Use has been made of all sets 
of data extending from 1920 to 1940 and 
also the readings for 15 or more years from 
a few stations in thinly settled areas. Few 
complete records for more than 20 years 
are available. Lack of records of daily 
precipitation over long periods has been a 
handicap. For the past 5 years the Mexican 
Meteorological Service has kindly supplied 
copies of its daily weather map, carrying 



daily rainfall readings, which will even- 
tually furnish a basis for more accurate 
work on rainfall intensity, daily extremes, 
and duration of drought periods. 

Variation in the annual rainfall total is 
well known to increase as the mean total 
becomes smaller. In tropical Mexico and 
just outside the borders of the desert in 
northern Mexico, the wettest years yield 
from 1.5 to 3 times the total for the driest 
years. In the Sonoran Desert there are 
stations at which the fall in wet years has 
been from 16 to 329 times that of the driest 
years. 

Rainless periods of more than 1 month 
are rare outside the desert on the east 
coast. In the Chihuahuan Desert several 
stations have had rainless periods of 4 
months during the 20 years. In the Sono- 
ran Desert periods of 10 to 18 months 
without rain have been experienced at 
five stations. These long periods are par- 
ticularly characteristic of Baja California 
and the Gulf coast of Sonora. Their im- 
portance to vegetation is obvious. At Ma- 
zatlan, Sinaloa, well within the thorn for- 
est region, the longest rainless period was 
7 months, an eloquent testimonial to the 
semiarid character of the thorn forest. 

As one crosses northern Mexico from 
west to east (Ensenada, Baja California to 
Matamoros, Tamaulipas), the differences 
in total rainfall are outweighed in impor- 
tance by the pattern of seasonal distribu- 
tion. The rainfall of northern Baja Cali- 
fornia is confined to the winter, that of 
northern Sonora is biseasonal, that of Chi- 
huahua is mainly in the 4 summer months, 
that of Coahuila is rather evenly distrib- 
uted through the last 8 months of the year, 
and that of northern Tamaulipas (which 
is outside the desert) is well distributed 
throughout the year, with early and late 
summer maxima. These great differences 
in seasonal distribution are correlated with 
marked differences in vegetation. 



i38 



CARNEGIE INSTITUTION OF WASHINGTON 



As one crosses Sonora and Sinaloa from 
north to south, there is found to be a sharp 
increase of rainfall between Ciudad Obre- 
gon, Sonora and Culiacan, Sinaloa, at the 
transition from desert to thorn forest. Also 
there is a gradual decrease of winter rain- 
fall between the international boundary 
and Mazatlan, and an increase of summer 
rainfall. At Nogales, Sonora, the rain of 
July, August, and September is 60 per cent 
of the annual total, whereas at Mazatlan 
it is 79 per cent. In southern Arizona and 
northern Sonora a biseasonal rainfall of 
8 to 12 inches is found in the desert, but 
at Culiacan and Mazatlan a nearly uni- 
seasonal rainfall of 24 and 28 inches re- 
spectively serves to maintain the thorn 
forest. 



Throughout the southwestern United 
States and northern Mexico the gradients 
of altitudinal change in rainfall are con- 
trolled by distance from the sea, by pre- 
vailing winds, by the steepness of slope of 
the land masses or mountains that are en- 
countered, and by the summit altitude of 
the mountains. The influences exerted on 
vegetation by rainfall are further compli- 
cated by temperature conditions, slope ex- 
posure, underlying rock and soil, and other 
conditions. The topographic influences on 
rainfall are of great importance in the 
control of the several types of vegetation 
in northern Mexico. The conditions are 
such, however, that there is no altitudinal 
control of the occurrence of desert, which 
exists from sea level to 7200 feet. 



PALEOBOTANY 

Ralph W. Chaney 



As has been emphasized in previous re- 
ports, the climatic and topographic setting 
of living plants, readily determinable from 
a study of modern environments, may be 
projected back into the past to a time when 
similar vegetation covered the earth, leav- 
ing its record as fossils in the rocks. In- 
terpretation of Tertiary floras, whose mem- 
bers have survived in modified form in 
the forests of today, provides many details 
regarding the physical history of North 
America. During the early years of our 
study of Tertiary paleobotany in the west- 
ern United States, the close similarity of 
certain fossil floras to living forests became 
apparent. In our first discussions of the 
Bridge Creek and Mascall floras, relation- 
ships to the modern redwood forest, to the 
border redwood forest, and to deciduous 
forests in eastern North America and 
Eurasia were indicated. Subsequently 
reference has regularly been made to 
groups of fossil species whose equivalents 
have survived in modern forests, the 



groups being termed the Redwood ele- 
ment, the Deciduous element, and the 
Asiatic element of the flora involved. 

In later years, elements in Tertiary floras 
have been designated by several workers 
in western America, but the application 
of names has not always been consistent. 
It seems desirable at this time to stand- 
ardize the use of the terms applied, and to 
clarify the implications of such usage. In 
consultation with Drs. Herbert L. Mason, 
Lincoln Constance, and Daniel I. Axelrod, 
all of whom have spent much time con- 
sidering the problem, definitions and a 
classification have been devised. A fossil 
flora may be broken down into elements 
whose living equivalent species are found 
in association at the present time. An ele- 
ment may be defined as a group of fossil 
plants whose modern related species oc- 
cupy a major geographic and climatic prov- 
ince. 

In all Tertiary floras studied, divergent 
types of vegetation may be noted which 



DIVISION OF PLANT BIOLOGY 



139 



are assignable to several elements. The 
five elements commonly designated in Ter- 
tiary floras of western North America are : 

1. The West American element is made 
up largely of conifers, with broad-leafed 
evergreens commonly present. The region 
which their most typical living equivalents 
now occupy is characterized by temperate 
climate, with winter rainfall and summer 
drought, and with a moderate range of 
temperature. 

2. The East American element is made 
up largely of broad-leafed deciduous genera, 
with conifers of minor importance. The re- 
gion on the eastern side of North America 
now occupied by their living equivalents is 
characterized by temperate climate, with well 
distributed rainfall of which a considerable 
amount falls during the summer, and with 
seasonal extremes of temperature, most trees 
losing their leaves during the cold season. 

3. The East Asian element is made up of 
genera now confined to eastern Asia, and 
includes also genera occurring in other parts 
of the world whose species show close re- 
semblance to those now living on the western 
side of the Pacific. The climatic require- 
ments of the living equivalents of this ele- 
ment are essentially the same as those out- 
lined for the equivalents of the East Ameri- 
can element, except that the East Asian ele- 
ment also includes genera which now range 
into the tropics. 

4. The Southwest American element is 
made up largely of microphyllous plants 
whose living equivalents have their centers 
of distribution in the mountains of northern 
Mexico, extending northward into New 
Mexico and Arizona, and along the coast 
from Cape San Lucas to central California 
and into the interior. Seasonal extremes both 
of temperature and of precipitation charac- 
terize these regions, in which the climate is 
temperate except at the south. 

5. The Caribbean element is made up 
mostly of evergreen angiosperms with large, 
entire-margined, thick leaves. The region 
occupied by the modern equivalents of Ter- 
tiary members of this element, including 



southern Mexico and much of Central Amer- 
ica, has a subtropical to tropical climate, with 
high, generally well distributed rainfall and 
temperatures free from frost. 

The Caribbean element in the Tertiary 
of western North America is best devel- 
oped in floras of Eocene and Lower Oligo- 
cene age. It survived into the Miocene of 
Washington and Oregon in coastal and 
other favorable situations, and has been 
noted with greatly reduced representation 
in Pliocene floras as far north as central 
California. The West American element 
is dominant in Upper Oligocene and Mio- 
cene floras of the western United States, 
continuing into the Pliocene and down to 
the present at middle latitudes, and in the 
mountains farther south. The East Ameri- 
can and East Asian elements are also 
abundantly represented in floras of Middle 
Tertiary age, becoming rare in the Plio- 
cene and disappearing at the close of the 
epoch. The Southwest American element 
makes its first well established appearance 
in the Miocene of southern California, al- 
though there is reason to think that it 
may have been represented in the Floris- 
sant flora of Colorado, which MacGinitie 
believes to be of Oligocene age. It ranged 
northward into Oregon and Idaho at the 
close of the Miocene, and was restricted 
southward during the Pliocene. 

A complete enumeration of modern 
plant climaxes in North America must 
of course include a grassland unit, which 
might be termed the Interior American 
element. Since our classification refers not 
to modern but to Tertiary vegetation, and 
since fossil collections from the western 
United States include no important repre- 
sentatives of the grassland climax, we have 
not designated an element corresponding 
to it. The important studies of fossil 
grasses by Elias may at some future time 
warrant the inclusion of an Interior Amer- 
ican element made up of Tertiary grasses 



140 



CARNEGIE INSTITUTION OF WASHINGTON 



and forbs. In the same way, it may even- 
tually be desirable to set up a Boreal 
American element to include Tertiary 
plants whose modern equivalents are now 
most characteristic of high North Ameri- 
can latitudes. Such plants appear to make 
up an important part of several older Ter- 
tiary floras from the arctic islands, but 
since they are not well represented in the 
fossil floras of Oregon and adjacent areas, 
the Boreal American element is not in- 
cluded in the classification here presented. 
From even a cursory reference to the 
distribution of tree genera in modern for- 
ests, it is apparent that there must be some 
overlapping of the constituents of these 
elements. The East American and East 
Asian elements each have distinctive gen- 
era; but there are others common to the 
two which have species so similar that they 
may equally well be considered as the 
fossil equivalents of species now living 
either in eastern America or in eastern 
Asia. The marked similarity between the 
vegetation on the east sides of the two 
continents has been well known since the 
days of Asa Gray, and is to be expected 
because of the climatic similarity of the 
regions. But there are also differences, 
which are emphasized by the study of 
forest evolution in the western United 
States; it therefore seems essential that 
separate element rank be assigned to these 
major forest units of the two continents. 
There are likewise close relationships be- 
tween the East and West American ele- 
ments; it is not always possible to de- 
termine whether a fossil species of syca- 
more, Platanns dissecta Lesquereux, has as 
its modern equivalent the eastern species, 
P. occidentalis Linnaeus, or the western 
species, P. racemosa Nuttall; one of the 
most common fossil species of black oak, 
Quercus pseudo-lyrata Lesquereux, seems 
almost equally related to living oaks on 
both sides of the continent. Such dual 



representation of fossil species is to be ex- 
pected in a classification as general as ours, 
and serves to emphasize the common ori- 
gin of forests now widely separated, but 
intermingled in the generalized vegetation 
of the Tertiary period in the western 
United States. 

A further comment seems necessary to 
clarify our attitude toward comparisons 
between fossil and modern plants. All our 
lists of equivalent living species are at 
best a tentative expression of opinion re- 
garding the modern affinities of fossil spe- 
cies. These suggested relationships are 
based largely on leaf similarities, with the 
supporting evidence of fruits or seeds also 
available in some cases. Such comparisons 
are highly suggestive, and are made when- 
ever the fossil specimens are sufficiently 
well preserved; but they are not to be con- 
sidered as final evidence of phylogenetic 
relationships. Whether a fossil oak finds 
its nearest living descendant in the forests 
of North America or in those of eastern 
Asia, the fact that similar living species 
may be noted on both continents is highly 
significant in any consideration of the 
Tertiary history of vegetation in the north- 
ern hemisphere. Such relationships also 
make possible a more natural interpreta- 
tion of the origins of modern forests. 

Each of the elements designated in Ter- 
tiary floras may be further subdivided into 
components which represent their major 
floristic units. Component names are as- 
signed to emphasize dominant plants, 
secondary topographic features, or climatic 
zones. The components most commonly 
recognized in discussing the Tertiary his- 
tory of the West American element are 
the Redwood, the Border-redwood, the 
North-coast coniferous, the Sierra-Cascade, 
and the Rocky Mountain. Usage will 
vary somewhat until the significance of 
these components in Tertiary vegetation 
becomes better understood. The Border- 



DIVISION OF PLANT BIOLOGY 



I 4 I 



redwood component may represent an 
ecotone between the Redwood compo- 
nent and two components of the South- 
west American element, the Oak wood- 
land and the Chaparral. Locally the 
modern forest equivalents of the North- 
coast coniferous and the Sierra-Cascade 
components grade into one another, and 
their place as distinct units in the forests 
of the Tertiary may in some cases be open 
to question. 

A natural division of the East Ameri- 
can element would recognize the Beech- 
maple, the Oak-hickory, the Coastal pine, 
and the Swamp cypress-tupelo compo- 
nents. All these except the Coastal pine 
are well represented in the Middle Terti- 
ary floras of the western United States. 
It is possible that additional components 
may be designated as current studies of 
the Mascall and Bridge Creek floras of 
Oregon are continued. 

The East Asian element is subdivided, 
largely on the basis of climatic and topo- 
graphic units, into Northern temperate 
highland, Northern temperate lowland, 
Southern temperate highland, Southern 
subtropical lowland, and Southern tropical 
lowland components. It seems probable 
that future field studies in Asia will make 
possible floristic and geographic names cor- 
responding to those assigned to the com- 
ponents of the East American element, 
names which will carry a more significant 
connotation. 

The Southwest American element is di- 
visible into the above-mentioned Oak 
woodland and Chaparral components, and 
also into Conifer woodland, Closed-cone 
pine, and Coastal sage. The Oak wood- 
land component, occurring under a wide 
range of topographic and climatic condi- 
tions, represents a more diverse floral unit 
than the other components of the South- 
west American element; but it does not 
appear to indicate a wider range of com- 



position than do certain components in the 
East American and West American ele- 
ments. 

The subdivisions of the Caribbean ele- 
ment, as in the case of the East Asian, are 
tentative as here presented. They include 
the Warm-temperate highland, Subtropical 
lowland, and Tropical lowland compo- 
nents. More definite component names 
will be assigned in future discussions of 
Eocene floras, in which the Caribbean 
element is largely represented. 

It should be emphasized that element 
and component names are applied to 
groups of fossil plants to emphasize their 
resemblance to modern vegetation, and 
that they do not necessarily coincide with 
the names or units involved in the study of 
living plants. In cases where groups of fos- 
sil plants have living equivalents occupying 
well defined geographic or climatic prov- 
inces and subprovinces, it is convenient 
to designate them in terms of these living 
equivalents and their habitats. Our ele- 
ment and component names indicate the 
present distribution of surviving equiva- 
lents of Tertiary species, not their past dis- 
tribution; there is no inherent basis for 
assuming that a Miocene oak assigned to 
the East American element was living in 
the eastern United States during that 
epoch; only its discovery there in Miocene 
rocks would indicate that its range at 
that time coincided with its present dis- 
tribution. Further, there is not the slight- 
est implication that the provinces covered 
by element names represent the centers 
of dispersal of the plants involved. The 
modern occurrence of Cercidiphyllum is 
no more an indication that it had its origin 
in China than is the presence of Sequoia 
in California evidence that it is a native 
son. Centers of origin and modern range 
of species may in some cases coincide; 
but when there is a wide time dis- 
crepancy between the living tree and its 



142 



CARNEGIE INSTITUTION OF WASHINGTON 



fossil equivalent, there are likely also to 
be wide discrepancies between their Ter- 
tiary and Recent distribution, representing 
the distances covered in the course of for- 
est migrations through geologic time. 

One further consideration warrants brief 
comment at this point. Many floras, espe- 
cially those of Middle Tertiary age, in- 
clude several elements representing for- 
ests now widely separated in regions with 
diversified climates. We conclude that 
such vegetation was of a more generalized 
type than are most living forests. Physi- 
cal changes toward the later part of the 
Tertiary period brought diversified topog- 
raphy and climate, producing the geo- 
graphic and climatic provinces which we 
recognize, each with its distinctive forest. 
Differentiation of the generalized vegeta- 
tion of the past into modern floristic units 
may best be expressed by the recognition of 
diverse ingredients in Tertiary forests. 
Such ingredients, which we term elements 
and components, represent groups of trees 
whose varying response to earth change 
has resulted in their restriction to the mod- 
ern regions best suited to their require- 
ments. A survey of modern forest environ- 
ments and a comparison of their vege- 
tation with that of the past provides the 
most adequate basis for our understanding 
of continental history, since it makes pos- 
sible a reconstruction of the topographic 
and climatic setting of Tertiary forests. 

During the past year a significant com- 
parison has been made between the swamp 
cypress forest of southern Indiana and 
the Mascall flora from the Miocene of 
Oregon. Unlike the Taxodium forest liv- 
ing farther south, the swamp cypress near 



the northern limits of its range is closely 
associated with black oak, hickory, and 
maple. These trees grow on the borders 
of the swamp, and their leaves may be 
found mingled with those of the cypress 
in sediments now accumulating. Similar 
accumulation of leaves in the lake deposits 
of Oregon's past has given us a fossil as- 
semblage with essentially the same com- 
position, and a closely similar environment 
is indicated. Unlike the somewhat older 
Bridge Creek flora, in which Sequoia is the 
dominant conifer, the Mascall assemblage 
suggests the presence of swamps and lakes 
during later Miocene time. Known facts 
regarding the geologic history of the John 
Day Basin during this stage are consistent 
with such a topographic picture. Immense 
amounts of volcanic ash were accumulat- 
ing along the courses of streams, which 
were locally overloaded with these sedi- 
ments, or dammed by lava flows. By con- 
trast, the Bridge Creek shales laid down at 
the close of the Oligocene and the begin- 
ning of the Miocene seem to represent 
valley accumulation under more normal 
conditions of gradation. The modern oc- 
currence of the redwood is confined to 
well drained valleys, and that of the swamp 
cypress to those which are poorly drained. 
The difference between the Bridge Creek 
and Mascall floras may be due more to 
topographic than to climatic changes dur- 
ing Middle Tertiary time. 

The studies of Dr. Chaney's associates, 
Daniel I. Axelrod, Erling Dorf, and Harry 
D. MacGinitie, have continued along the 
lines outlined in recent reports. Their pub- 
lications are listed in the bibliography. 



DIVISION OF PLANT BIOLOGY 



143 



BIBLIOGRAPHY 



Axelrod, Daniel I. The concept of ecospecies 
in Tertiary paleobotany. Proc. Nat. Acad. 
Sci., vol. 27, pp. 545-551 (1941). 

Clausen, Jens, David D. Keck, and William M. 
Hiesey. Regional differentiation in plant 
species. In Symposium on the species con- 
cept. Biological Symposia, vol. 4, pp. 261- 
280. Lancaster, Penna., Jacques Cattell Press 
(1941). 

See Hiesey, William M. 

Emerson, Robert, and Charlton M. Lewis. 
Carbon dioxide exchange and the measure- 
ment of the quantum yield of photosynthesis. 
Amer. Jour. Bot., vol. 28, pp. 789-804 (1941). 

The photosynthetic efficiency of 

phycocyanin in Chroococcus, and the prob- 
lem of carotenoid participation in photo- 
synthesis. Jour. General Physiol., vol. 25, 

PP- 579-595 (1942). 

Hiesey, William M., Jens Clausen, and David 
D. Keck. Relations between climate and in- 
traspecific variation in plants. Amer. Natu- 
ralist, vol. 76, pp. 5-22 (1942). 

■ See Clausen, Jens. 

Keck, David D. Penstemon. In Flowering plants 
and ferns of Arizona, by Thomas H. Kearney 
and Robert H. Peebles, pp. 806-817. U. S. 
Dept. Agric. Misc. Pub. No. 423 (1942). 

See Clausen, Jens; Hiesey, William M. 

Lewis, Charlton M. See Emerson, Robert. 

MacGinitie, Harry D. A Middle Eocene flora 
from the central Sierra Nevada, iii +178 
pp. Carnegie Inst. Wash. Pub. 534 (1941). 

Manning, Winston M. See Strain, Harold H. 

Nobs, Malcolm A. Cytology. In Ceanothus, by 
Maunsell Van Rensselaer and Howard E. 



McMinn, pp. 149-153. Santa Barbara, Calif., 
Santa Barbara Botanic Garden (1942). 
Shreve, Forrest. Grassland and related vegeta- 
tion in northern Mexico. Madrono, vol. 6, 
pp. 190-198 (1942). 

The desert vegetation of North America. 

Bot. Rev., vol. 8, pp. 195-246 (1942). 

The vegetation of Jamaica. Chronica 

Botanica, vol. 7, pp. 164-166 (1942). 

Vegetation of Arizona. In Flowering 



plants and ferns of Arizona, by Thomas H. 
Kearney and Robert H. Peebles, pp. 10-23. 
U. S. Dept. Agric. Misc. Pub. No. 423 (1942). 

Spoehr, H. A. Origin and transformation of 
carbohydrates in plants. Jour. Chem. Edu- 
cation, vol. 19, pp. 20-23 ( x 94 2 )- 

Strain, Harold H. Isomerization of polyene 
acids and carotenoids. Preparation of beta- 
eleostearic and beta-licanic acids. Jour. Amer. 
Chem. Soc, vol. 63, pp. 3448-3452 (1941). 

Chromatographic adsorption analysis. 

x + 222 pp. New York, Interscience Pub- 
lishers, Inc. (1942). 

Chromatographic adsorption analysis. 

Indus, and Engin. Chem., Anal. Ed., vol. 14, 
pp. 245-249 (1942). 

and Winston M. Manning. Unsaturated 

fat oxidase: specificity, occurrence and in- 
duced oxidations. Jour. Amer. Chem. Soc, 
vol. 63, p. 3542 (1941). 

The occurrence and intercon- 



version of various fucoxanthins. Jour. Amer. 
Chem. Soc, vol. 64, p. 1235 (1942). 
Wiggins, Ira L. Acacia angustissima (Mill.) 
Kuntze and its near relatives. Contr. Dudley 
Herbarium, vol. 3, pp. 227-239 (1942). 



DEPARTMENT OF EMBRYOLOGY 

Baltimore, Maryland 
GEORGE W. CORNER, Director 



The program of the Department of 
Embryology has followed, as fully as 
present conditions permit, the plans set 
forth in last year's report. The collection 
of embryos has been increased by many 
acquisitions, notably a number of very 
early human embryos which are described 
below. The publication of several papers 
and a comprehensive volume on the embry- 
ology of the rhesus monkey marks the 
completion of the general exploration of 
that subject which has been under way 
for some years, although many special 
problems remain to be studied. The work 
in experimental embryology, using the re- 
markable advantages afforded by the 
opossum, in which the young, while still 
in embryonic condition, are accessible in 
the brood pouch, proceeds successfully and 
is yielding results which will appear in 
the next report. Studies, by physical 
methods, of placental function and of the 
measurement of the sex-gland hormones 
in the blood and tissues have been inter- 
rupted by the transfer of the investigators 
concerned to duties directly connected 
with war service, but the work on the 



placenta had fortunately gone so far that 
it has been possible to set down a con- 
siderable body of results and to draw in- 
structive general conclusions. A general 
investigation of the mammary gland of 
the monkey and its reaction to the sex- 
gland hormones has reached a similar 
stage. Details of these and other projects 
will be found in the following pages. 
Although at the present writing it is dif- 
ficult to foresee the course of events, even 
within the relatively sheltered walls of a 
research laboratory of embryology, it ap- 
pears that we shall be able to preserve 
and exploit our unique collections and to 
keep up a significant part of the investiga- 
tive program, while doing everything 
possible to share in the national effort. 

During the year the facilities of the 
Department were made available to a 
number of scientific visitors, including 
Dr. Joseph Gillman, of the University of 
the Witwatersrand; Dr. Emil Witschi, of 
the University of Iowa; and Dr. T. L. 
Terry, of the Massachusetts Eye and Ear 
Infirmary. 



EMBRYOLOGY 



Early Human Embryos of the Pre- 
villous Stage 

This year the Department is again able 
to report notable progress in the study 
of early stages of human development. 
In 1939 (Year Book No. 38) Dr. Streeter 
mentioned the acquisition of two new hu- 
man embryos, of about the nth and 12th 
days, which had been obtained by Drs. 
A. T. Hertig and J. C. Rock, of Boston. 



These two complete and perfect speci- 
mens, together with the previously known 
but incomplete Miller ovum, formed a 
group at what was then the earliest known 
stage of human development, so that an 
important period which had been known 
only hypothetically (so far as the human 
species is concerned) has now become 
known by actual observation. 
Some information about these two valu- 



13 



T 45 



146 



CARNEGIE INSTITUTION OF WASHINGTON 



able embryos was made public by Dr. 
Hertig and Dr. Streeter in lectures and 
demonstrations to scientific societies; pho- 
tographs and reconstructions illustrating 
them were exhibited at the 1939 Annual 
Exhibition of the Carnegie Institution, and 
photographs have even been made availa- 
ble for use in one or two textbooks. Thus 
these embryos have already to some slight 
degree contributed to professional knowl- 
edge. Drs. Hertig and Rock have now 
completed their detailed study, and full 
descriptions of both embryos appear in the 
current volume (XXIX) of the Carnegie 
"Contributions to Embryology." It is now 
a pleasure to announce that these indefat- 
igable investigators, whose work has been 
aided by a grant from the Carnegie Cor- 
poration of New York, have continued 
with success their painstaking search for 
early human embryos. Up to the present 
they have obtained and deposited in our 
collection no less than 52 specimens, among 
which are 12 embryos of the 2d and early 
3d weeks. Of these, 7 are to all appear- 
ances normal and 5 show various abnor- 
malities. It need hardly be added that the 
earliest disturbances and abnormalities of 
human development are quite as important 
as the normal stages. 

During the past year Drs. Hertig and 
Rock have obtained two embryos defi- 
nitely earlier than any previously known, 
one of them believed to be gY 2 days old 
(Carnegie no. 8004) and the other y]/ 2 
(Carnegie no. 8020). These, like all the 
others, have been successfully cut into 
sections, stained, and mounted by Dr. 
Heuser, Mr. Heard, and Miss Caspari, and 
fully photographed by Mr. Reather. 

This special collection of human em- 
bryos constitutes an inestimable scientific 
treasure, rich in precise information about 
the development of the embryo and espe- 
cially about the first stages of its attach- 



ment to the mother, before the develop- 
ment of placental villi and of the yolk sac. 

Descriptions of the first two of the 
Hertig-Rock embryos, nos. 7699 and 7700 
of the Carnegie Collection, have been pub- 
lished in full, as mentioned above. Their 
nature will be made clear to those readers 
of this report who are not biologists by the 
accompanying diagrams (figs. 1, 2). Both 
embryos are earlier than the stage repre- 
sented by the first (left-hand) sketch in 
figure 1. No. 7699 is believed to be 11 days 
old, no. 7700 to be 12 days old. They are 
both very small. Either of them would 
quite easily pass through the open space 
of the small letter "o" of the type in which 
this report is printed. As will be seen in 
figure 2, both of them have barely finished 
growing into the lining of the uterus, be- 
ing separated from its cavity by only a 
thin layer of tissue. At this stage the 
embryo itself is very simple, consisting 
of a disk of ectoderm with a disk of endo- 
derm applied to its ventral side. In the 
case of the younger embryo this bilaminar 
embryonic disk is roughly circular, so 
that it is not yet possible to determine 
with certainty the direction of the future 
long axis of the body it is destined to form. 
Its diameter is 0.138 mm.; that is to say, 
7 such embryonic disks, if arranged in 
one layer on the printer's period at the 
end of this sentence, would not completely 
cover it. In the older embryo this "disk" 
has grown a little longer and narrower. 

Over the back, so to speak, of the em- 
bryonic area, in each of these embryos, the 
amniotic cavity is already visible. Ventral 
to the endoderm is a cavity in the region 
where the yolk sac will become well de- 
fined a day or two later. This cavity is 
walled by the delicate exocoelomic mem- 
brane (Heuser's membrane). Just how the 
first cells of the endoderm are related to 
this membrane, and how the membrane, in 



DEPARTMENT OF EMBRYOLOGY 



147 





Fig. 1. Diagram showing location and development of the human embryo. The left-hand 
figure represents a stage a little later than the Hertig-Rock embryos mentioned in the text 
(embryo is drawn disproportionately large with respect to the uterus). 



Germ disk 



Uterus 



Germ disk 




Trophoblast 



Extraembryonic 
mesoblast 



Primit 



miTive E xocoe | omlc 
endoderm mem brane 



Uterus Germ disk Trophoblast 




Trophoblast 

Primitive 
Extraembryonic endoderm Uter- 

mesoblast Amnion Germ disk 




Primitive 
endoderm 



Exocoelomic 
membrane 



Primitive 
endoderm 



Fig. 2. A and C are diagrams of the Hertig-Rock embryos, Carnegie nos. 7699 and 7700 respec- 
tively. B and D show two previously known but slightly more advanced embryos, namely the 
Miller ovum as reconstructed by Streeter, and the Werner (Stieve) embryo. 



148 



CARNEGIE INSTITUTION OF WASHINGTON 



turn, is related to the yolk sac, are ques- 
tions still eagerly discussed by those who 
have studied these early embryos, but 
destined no doubt to be cleared up in sub- 
sequent publications. 

The cavity in which each embryo lies, 
relic of the original blastocyst cavity, is 
surrounded by the trophoblast or outer 
cell layers, whose function is to establish 
relations with the maternal blood circula- 
tion. Already in these early embryos the 
trophoblast has differentiated into an in- 
ner cytotrophoblast and an outer syncytio- 
trophoblast. The latter, as indicated in 
figure 2 (and of course fully illustrated in 
the article by Hertig and Rock), has be- 
gun to form a series of cavities, the tropho- 
blastic lacunae. Into these spaces the ma- 
ternal blood capillaries early begin to open, 
so that some of them, even in the younger 
specimen, contain maternal blood. The 
inner layer, the cytotrophoblast, is in the 
older specimen beginning to form cell 
groups pushing outward into the syncytio- 
trophoblast. In the cores of these knobs 
(which are the first beginnings of the pla- 
cental villi) the earliest signs of the em- 
bryonic blood vessels are seen as a primi- 
tive angioblast. The rudiments of the 
uteroplacental circulation are thus laid 
down. There is no necrosis of maternal 
tissues. Early decidual cells are forming 
in the stroma of the endometrium adja- 
cent to the embryonic trophoblast. 

In the case of the younger embryo, 
750 cc. of the maternal urine collected 
during the 2 days preceding operation, 
when concentrated and injected into a rat, 
produced ovarian changes characteristic of 
the Zondek-Aschheim test for pregnancy, 
a truly remarkable finding in view of the 
early stage of pregnancy. 

Two Human Embryos in the Presomite 
Stage 
Dr. Joseph Krafka, Jr., of the University 
of Georgia, contributes to volume XXIX of 



the "Contributions to Embryology" a de- 
scription of a human embryo of the pre- 
somite stage. This is the Torpin ovum, 
so called after Dr. Richard Torpin, of the 
Department of Obstetrics and Gynecology 
of the University of Georgia, who obtained 
it at operation. Its age is estimated to be 
13 days. The specimen is complete and in 
a good state of preservation. It is particu- 
larly interesting with regard to the blood 
vessels at the site of implantation, since 
it well shows the early development of the 
venous sinusoids characteristic of this stage 
of attachment. Dr. Krafka has given not 
only a clear description of the specimen, 
but also a good deal of interpretative analy- 
sis which must be taken into consideration 
when a general account of human embryos 
of this period comes to be written. 

Dr. H. O. Jones and Dr. John I. Brewer, 
of the University of Chicago, present in 
the same volume an account of an em- 
bryo in the primitive-streak stage, esti- 
mated to be iS l / 2 days old. It is designated 
as the Jones-Brewer ovum I (not to be 
confused with the Edwards-Jones-Brewer 
embryo, Contributions to Embryology, vol. 
XXVII). It shows the earliest stage of 
the head process thus far described in the 
human embryo. The first signs of the 
neurenteric canal appear as three small 
spaces within the primitive knot (Hensen's 
node). The specimen is therefore espe- 
cially instructive for study of the so-called 
gastrulation of the human embryo. 

Embryology of the Rhesus Monkey 

For more than twenty years this labora- 
tory has been investigating the embryology 
of the rhesus monkey. It is hardly neces- 
sary to explain the value of such a study 
of the development of one of the infra- 
human primates, carried on in parallel 
with that of the human. The experience 
thus obtained and the resulting large col- 
lection of monkey embryos, obtained ex- 



DEPARTMENT OF EMBRYOLOGY 



149 



perimentally and therefore properly timed 
and preserved, has served to guide the 
study of very early human embryos such 
as are discussed above. Knowledge of the 
physiology of reproduction in the monkey, 
gained in the course of this work, has con- 
tributed greatly to our understanding of 
menstrual phenomena and ovarian func- 
tion in mankind as well as in the monkey 
itself. Moreover, as will be emphasized a 
little later, this study of the monkey, re- 
vealing for the first time the earliest stages 
of primate development, contributes to em- 
bryological thinking in general. 

In 1921, the embryology of the monkey 
was quite unknown and the general physi- 
ology of reproduction in this animal was 
not understood. In 1942 the rhesus mon- 
key is in these respects one of the best- 
known mammals. The work on this spe- 
cies has been led in this laboratory by Drs. 
G. L. Streeter, C. H. Heuser, and C. G. 
Hartman, whose part in it was referred to 
in last year's report (Year Book No. 40). 
These workers have been in constant touch 
with colleagues studying monkeys in other 
laboratories, including especially Drs. G. B. 
Wislocki, of Harvard University; G. W. 
Bartelmez, of the University of Chicago; 
J. B. Markee, of Stanford University; and 
G. W. Corner while he was at the Uni- 
versity of Rochester. All these investigators 
have added to the subject through articles 
in the "Contributions to Embryology" as 
well as in other journals. 

It has been possible to publish this year 
three papers which describe the develop- 
ment of the rhesus monkey from the egg 
in the ovary until birth. Drs. C. G. Hart- 
man and G. W. Corner describe six ovar- 
ian eggs, two of which were undergoing 
the first maturation division. In the mon- 
key, as in the majority of mammals, the 
first maturation division occurs within 
the follicle just preceding its rupture. The 
egg therefore leaves the ovary with the 



polar body formed and the second polar 
division in progress. Drs. W. H. Lewis 
and C. G. Hartman take up the story at 
this point with the description of eight eggs 
recovered from the oviduct, two of which 
were in the 2-cell stage and six were non- 
fertile. To these may be added four eggs 
previously described by the same authors, 
from the 2-cell to the 16-cell stage. 

The long campaign of investigation of 
monkey embryology is brought to a climax 
in this volume by an extensive monograph 
on development of the macaque embryo 
by Drs. C. H. Heuser and G. L. Streeter. 
This work is first of all a photographic 
atlas on the subject. Its 33 plates, compris- 
ing 259 separate photographs, illustrate 
every stage of development from the early 
blastocyst of 8 days to the fetus of 57 days. 
The article includes a systematic list of 
123 specimens used in the work, which are 
now available for reference in the Car- 
negie Embryological Laboratory. The ac- 
companying text covers especially the pe- 
riod from the early blastocyst to the stage 
of somite formation; ;hat is to say, the 
period of development least well known 
in the human species and that in which all 
the outstanding problems of primate and 
even of general mammalian embryology 
are centered. 

This account is remarkable for several 
reasons. Well aware of the novelty of their 
material, which as they say has turned an 
entire new page in primate embryology, 
the authors have described it in a fresh 
and unconventional way. They have em- 
phasized the idea that the embryo is not 
merely a morphological abstraction. It is 
indeed at every moment of its life a grow- 
ing organism with constituent parts and 
tissues which have their functions to per- 
form. Turning away from the diagram- 
matic interpretation and homologizing of 
earlier writers, the authors place little 
emphasis upon morphological theory, and 



150 



CARNEGIE INSTITUTION OF WASHINGTON 



set aside, at least temporarily, phylogenetic 
comparisons and the time-honored search 
for evidence of recapitulation. The result- 
ing discussion is often therefore very stimu- 
lating. For example, the authors see the 
embryo as a continuous center of undif- 
ferentiated formative tissue surrounded by 
an increasing body of specialized tissue. 
At first, when the ovum is a single cell, 
it is itself the undifferentiated mass. Then, 
as segregation proceeds and the wall of the 
blastocyst is formed, the inner cell mass 
continues to contain unoriented formative 
cells, which give rise to the germ disk. 
As the germ disk in turn differentiates, the 
primitive knot and probably the primitive 
streak remain as the undifferentiated cen- 
ter, which gives rise to specialized tissues 
as it gradually retreats tailward until all 
the undifferentiated tissue is used up. 

Likewise their description of the implan- 
tation of the embryo and the earliest steps 
in the development of the placental circu- 
lation is exceptionally complete and clear. 
It aids greatly in explaining the conditions 
in man, known from an incomplete series 
of isolated specimens. 

The correlation of age and form in the 
monkey furnishes dependable criteria of 
age in the human embryo. The growth 
curve of the macaque embryo, as well as 
the external form, is essentially the same 
as for human embryos during the first six 
weeks. The diverging characteristics ap- 
pear later in development. 

On other points there will be much dis- 
cussion. Any reader who follows, for ex- 
ample, the account of the origin of the 
yolk sac will see that the two authors hold 
different views, and he may find himself 
trying to make up his own homologies 
as he studies the photographic evidence 
presented. Some readers may feel that the 
emphasis on the immediate functional 
value of the embryonic organs leaves aside 
important considerations regarding the 



past and future history of these same or- 
gans. The authors have certainly rescued 
such structures as the early trophoblastic 
wall and the primitive streak from being 
merely tracings on a phylogenetic diagram, 
making us see them as living and func- 
tioning tissue; it will be sufficient, on the 
other hand, to mention the allantoic rudi- 
ment as an example of structures that can 
only be understood in the light of their 
homologies. Drs. Heuser and Streeter 
promise us, however, later papers in which 
their findings are to be related to the more 
familiar interpretation and terminologies. 

In his Hatfield Lecture at the College 
of Physicians of Philadelphia, 1941, Dr. 
Streeter has given a helpful summary of 
his concept of embryogenesis in monkey 
and man, based largely on the monograph 
just discussed. 

In order to make the Department's work 
on the embryology of the rhesus monkey 
readily available to laboratory workers, the 
Carnegie Institution has reissued in one 
volume these three papers from volume 
XXIX together with a paper on the growth 
of the monkey by Dr. A. H. Schultz, from 
volume XXVI, and one by Drs. G. B. Wis- 
locki and G. L. Streeter on the placenta- 
tion of the rhesus macaque, from volume 
XXVII. This special volume, which is 
Embryology Reprint Volume I, entitled 
Embryology of the rhesus mon\ey (Ma- 
caca mulatto), forms an almost complete 
embryological treatise on this species. Its 
usefulness has been appreciated by the 
investigators to whom copies have been 
distributed. 

Origin of the Rete Apparatus 

In Year Book No. 40 a brief report ap- 
peared of the finding of Dr. R. K. Burns, 
Jr., that in opossums the ostium of the 
Miillerian duct and the rete canals of the 
gonad are members of a series of primitive 
nephrostomes. In an article in Science (see 



DEPARTMENT OF EMBRYOLOGY 



151 



bibliography) these conclusions have now 
been published in detail, with an explana- 
tory diagram. 

Dr. Burns' investigation of the effect of 
the sex-gland hormones on the embryonic 
reproductive system of the opossum, men- 



tioned in the last Year Book, has pro- 
gressed notably. Some of the results were 
presented at the 1942 meeting of the 
American Association of Anatomists and 
at the June 1942 session of the Cold Spring 
Harbor Symposium. 



PHYSICO-CHEMICAL STUDIES 



Oxygen Consumption of the Embryonic 
Brain 

In the last report (Year Book No. 40) 
mention was made of the increasing ap- 
plication of physics and chemistry to em- 
bryology, and of our hope that such work 
may be carried forward in our laboratory. 
A good example of the kind of beginnings 
that are being made in this field is a paper 
by Drs. Josefa B. Flexner, Louis B. Flex- 
ner, and William L. Straus, Jr., on oxygen 
consumption and the oxidation mechanism 
in the cortex of the fetal brain, as related 
to the development of histological struc- 
ture. Using brain tissue from pig fetuses, 
readily available at the slaughterhouse, 
the investigators have applied the stand- 
ard techniques for measuring oxygen con- 
sumption and the activity of the respiratory 
enzymes. To cite their summary: Two 
critical periods, the first about halfway 
and the second about four-fifths of the way 
through gestation, have been found in the 
morphological differentiation of the fetal 
cerebral cortex. Both are characterized by 
rapid increase in size of the nerve cells, by 
changes in their form, and by abrupt 
changes in the quantity or pattern of the 
Nissl substance. During the first period, 
cytochrome-cytochrome oxidase activity 
shows a distinct rise, and during the sec- 
ond period, the Qo 2 increases to the level 
characteristic of the adult. Variations in 
cytochrome-cytochrome oxidase activity 
at different parts of the gestation period are 
not reflected in corresponding variations 



of Qo 2 . Cytochrome oxidase activity has 
been found constant at all stages of fetal 
development investigated. The increase in 
cytochrome-cytochrome oxidase activity 
with increasing fetal age consequently ap- 
pears due to an increase in concentration of 
cytochrome c. The Qofof fetal and adult 
cortex is about 1. 

Physiology of the Placenta 

In Year Books Nos. 39 and 40 mention 
was made of the program of research on 
the physiology of the placenta as an organ 
of transfer, under the direction of Dr. 
Louis B. Flexner, aided by Drs. Alfred 
Gellhorn and Herbert A. Pohl. Rapid 
progress has been made in the work, but it 
has necessarily been discontinued in 1942, 
because of Dr. Flexner's absence on duty 
with the National Research Council and 
the diversion of his colleagues to wartime 
projects. For this reason the present seems 
an appropriate time to summarize the 
results which have been achieved to date. 
Readers of this report who desire more de- 
tails than can be given here will find a 
review by Flexner and Gellhorn in the 
paper cited in the bibliography. A few 
passages and a table and diagram from 
this article are incorporated in the follow- 
ing statement. 

The first effort has been to determine 
the rate of transfer of relatively simple 
substances from mother to fetus through 
the placentas of various animals. For this 
purpose radioactive sodium has been 



152 



CARNEGIE INSTITUTION OF WASHINGTON 



chosen as the beginning tracer material, 
because it is easily prepared by the cyclo- 
tron or electrostatic-pressure generator, its 
behavior in the body is not complex, and 
it is one of the physiologically important 
chemical building stones of the organism. 
The radioactive salt was prepared with 
the high-voltage generator of the Depart- 
ment of Terrestrial Magnetism of the Car- 
negie Institution, and with the cyclotron 
of the Department of Physics of Harvard 
University. A solution of known potency 
is injected into the blood vessels of a preg- 
nant animal, and after a suitable time the 
fetuses are recovered by autopsy or Caesar- 
ean section. The amount of radioactive 
sodium which has passed from the ma- 
ternal blood across the placenta to the 
fetus is determined by measuring the 
amount of radioactivity in the ashed re- 
mains of the fetuses. 

Before planning the series of experi- 
ments, the investigators asked themselves 
the following questions, as expressed in 
their review: 

Does the permeability of the placenta 
vary with the period of gestation? If the 
answer be positive, what are the underly- 
ing causes for the variation ? Are there dif- 
ferences in permeability among the several 
morphologic types of placenta? Is the 
quantity of substance transferred across 
the placenta related to the rate at which 
the fetus is growing? Does the placenta 
act as an inert membrane or filter placed 
between the maternal and fetal circula- 
tions, or does it modify the transmission 
of substances by contributing energy to 
the process and so acting as an organ of 
secretion? How is the failure of a sub- 
stance to pass the placenta related to its 
physical and chemical characteristics? 
What effects do pathologic processes have 
upon placental transmission and so upon 
the nutrition of the fetus ? 

If the placentas of all mammals were 



alike in structure and function, the investi- 
gation would be relatively simple. The 
fact is, however, that placentas differ 
greatly in the degree of intimacy with 
which the maternal and fetal blood streams 
approach each other. Essentially, the pla- 
centa consists of a special area of the uter- 
ine lining, covered by a pavement of epi- 
thelial cells, supported on a layer of con- 
nective tissue, and underlain by a sub- 
surface bed of blood vessels. Against this 
lies an area of fetal membranes, also con- 
sisting basically of a layer of epithelial cells 
supported by connective tissue and under- 
lain by blood vessels. In the domestic pig, 
for example, this arrangement exists in full, 
and therefore a molecule of sodium chlo- 
ride going from the blood of the mother 
to that of the fetus, or a molecule of carbon 
dioxide going out, has to pass through all 
the tissues mentioned above as through 
a filter. It must traverse six layers, namely, 
the maternal blood-vessel wall (endothe- 
lium), connective tissue, and epithelium, 
and the fetal epithelium, connective tissue, 
and endothelial blood-vessel wall. 

In other species the maternal and fetal 
layers of the placenta are much more mani- 
folded and interlocked with each other 
than in the pig, and in various species the 
fetal epithelium and fetal connective tissue 
are lost. Thus the thickness and com- 
plexity of the barrier between the two 
blood circulations vary considerably in dif- 
ferent orders of mammals. There are in 
general four classes of placenta, as indi- 
cated in table i and in the diagram, figure 
3, based on Grosser's classification. 

The investigators studied, as is noted in 
the table, one species in each of the first 
of these placental groups and three with 
hemochorial placentas. 

It must be understood that the above- 
cited analysis and classification is not rigid. 
There are variations within each group, 



DEPARTMENT OP EMBRYOLOGY 



153 



and in individual species changes occur 
during the course of pregnancy. In the 
sow, for example, the epithelial layers be- 
come thinner as pregnancy advances. In 
the cat, guinea pig, and rabbit even the 
fetal (chorionic) epithelium largely dis- 
appears, bringing the maternal blood into 
contact with fetal blood vessels, and thus 



and fetal circulations, the greater the rate 
of transfer. The relative figures, expressing 
the amount of Na in milligrams trans- 
ferred across a unit weight of placenta per 
hour, at a comparable stage of late preg- 
nancy, are: sow, 0.026; goat, 0.41; cat, 
0.69; guinea pig, 6.1; rabbit, 6.8; rat, 8.3. 
It is very remarkable that such differences 



TABLE 1 

Cellular layers between maternal and fetal circulation 
(Grosser's classification of placentas) 





Maternal 


Fetal 




Type of placenta 


Endothe- 
lium 


Connec- 
tive 
tissue 


Epithe- 
lium 


Epithe- 
lium 


Connec- 
tive 
tissue 


Endothe- 
lium 


Examples 


Epitheliochorial . . . 
Syndesmochorial. . . 
Endotheliochorial. . 
Hemochorial 


+ 
+ 
+ 


+ 
+ 


+ 


+ 
+ 
+ 
+ 


+ 
+ 
+ 
+ 


+ 
+ 
+ 
+ 


Sow 

Goat, sheep, cow 
Cat 

Guinea pig, rat, 
rabbit, man 





FETAL 
SIDE 



MATERNAL 
-SIDE 




EPITHELIO- 
CHORIAL 



SYNDESMO- 
CHORIAL 



ENDOTHELIO- 
CHORIAL 



HEMO- 
CHORIAL 



Fig. 3. Diagrams indicating the number and kind of tissue layers interposed between maternal 
and fetal circulations in each of the four placental types. (From American Journal of Obstetrics 
and Gynecology, by courtesy of C. V. Mosby Company.) 



reducing the barrier between the two 
blood streams, in places at least, to an ex- 
ceedingly thin layer. 

Flexner, Gellhorn, and Pohl found in the 
first place that the rate of transfer of so- 
dium across unit weights of the four types 
of placenta varies according to the morpho- 
logical structure. The smaller the number 
of tissue layers placed between maternal 



should exist between animals whose nor- 
mal body temperature, pulse rate, and basal 
metabolism differ by no such great de- 
grees; but the fact is that among mam- 
mals the reproductive system is more var- 
ied than any other. 

In all six species there is a decided in- 
crease in the rate of transfer per unit 
weight of placenta as pregnancy advances. 



154 



CARNEGIE INSTITUTION OF WASHINGTON 



The reasons for this are not fully under- 
stood. 

The investigators next sought to know 
whether there is any relation between the 
rate of growth of the fetus and the supply 
of sodium received. The answer to this 
question can be obtained by comparing 
the supply of sodium to a gram of fetus 
per unit time with the rate at which that 
gram of fetus reproduces itself. The first 
of these quantities is found by simply di- 
viding the total sodium transferred to the 
fetus per hour by the fetal weight. The 
second quantity is the relative growth rate 
of the fetus and is obtained from data re- 
lating fetal weight to gestation age. If 
the placenta is nicely adapted to the needs 
of the fetus, one would expect a large 
amount of sodium to be transferred per 
gram fetus when the relative growth rate 
is high, since sodium is an integral part 
of each unit mass of tissue, and a lower 
transfer rate per gram fetus when the rela- 
tive growth rate is low. It was found that 
in all the six species studied there is a close 
relation between the rate of transfer per 
gram of fetus at any given stage of preg- 
nancy and the rate at which the fetus is 
growing at that time. When the fetus is 
small but growing rapidly, the rate of 
transfer of sodium is high; as it grows 
older and its relative growth rate drops, 



the supply of sodium per unit weight of 
fetus is commensurately low. There seems 
to be some mechanism underlying pla- 
cental function by which the rate of sup- 
ply of substances to the fetus is propor- 
tioned to its needs as a growing organism. 

A further important deduction concerns 
the safety factor, i.e., the ratio between the 
amount of sodium chloride transferred to 
the fetus and the amount retained by it 
for use in its life processes and growth. 
When this ratio is calculated from the 
observed data, it turns out that the margin 
of safety is large in all the species studied 
except the sow. The amount of sodium 
salt transferred is 25 to 50 times the amount 
retained by the fetus. In the sow, how- 
ever, the safety factor is much lower, 
being only 3.5 at the 16th week of ges- 
tation. 

This interesting work has recently been 
extended to the rhesus monkey, and it has 
also been possible to make observations 
on human pregnancy by cooperation of the 
Department of Obstetrics of the Johns 
Hopkins Medical School. In these later 
experiments "heavy water" (deuterium 
oxide) has been used as tracer substance 
as well as radioactive sodium. The final 
papers of the series are now in press and 
will be reported upon next year. 



THE REPRODUCTIVE ORGANS AND THEIR HORMONES 



Progesterone 

The rapid advance in knowledge of the 
reproductive hormones makes it necessary 
to review the subject frequently for the 
benefit of physicians and of investigators 
in collateral fields. In 1942 the American 
Medical Association brought out a revised 
edition of its handbook Glandular physi- 
ology and therapy. This contains a chap- 
ter contributed from our laboratory by 



Dr. Corner, which gives a summary of cur- 
rent knowledge about the corpus luteum 
hormone, progesterone, with especial ref- 
erence to its use in medical practice. 

Hormone Determination by Ultraviolet 
Spectrophotometry 

One of the most serious needs in the 
study of the sex-gland hormones is for 
more sensitive methods of detecting the 



DEPARTMENT OF EMBRYOLOGY 



155 



hormones in the tissues and in body fluids 
such as the blood and urine. Since the 
steroid substances have more or less char- 
acteristic absorption spectra, spectrophoto- 
metric methods are beginning to be tried. 
Dr. S. R. M. Reynolds, who joined the 
Department's staff in 1941, spent most of 
the year in familiarizing himself with the 
technique of ultraviolet spectroscopy and 
in planning for apparatus to be assembled 
in his laboratory. Meanwhile, with the 
cordial help of the Department of Physics 
of the Johns Hopkins University and with 
the collaboration of Dr. Nathan Ginsburg, 
Dr. Reynolds made a very hopeful begin- 
ning on the microdetermination of pro- 
gesterone. A preliminary account of this 
work was given before one of the scientific 
societies in the spring of 1942. A full ac- 
count is in press and will be reported next 
year. The work has had to be put aside 
for the duration of the war, since Dr. 
Reynolds has been commissioned in the 
Army Air Force and called to duty at the 
School of Aviation Medicine, Randolph 
Field, Texas. 

Drs. Carl G. Hartman and Harold 
Speert have investigated the effect of pro- 
gesterone on castrated monkeys without 
previous treatment with estrogenic hor- 
mone. Under natural conditions in the 
body, any female animal in whose ovary a 
Graafian follicle ripens, sheds its egg, and 
becomes a corpus luteum will of course 
already have been under the influence of 
the general ovarian (estrogenic) hormone. 
The question thus arises whether pro- 
gesterone can exert its characteristic effects 
at all if the uterus, vagina, and mam- 
mary glands are deprived of the estro- 
genic effect by long-standing castration. 
In general, experiments on lower mammals 
have shown that progesterone can be made 
effective in castrate animals by giving it 
in large dosage. The situation in monkeys 



has not been clear. Hartman and Speert 
gave 5 to 20 mg. of crystalline progesterone 
daily, for periods ranging from 20 to 32 
days, to monkeys castrated respectively 
37 days, 50 days, Sy 2 months, and 4 years. 
The hormone produced effects which 
were in part like those of progesterone 
following estrogens, and in part like those 
of estrogens given directly. Reddening of 
the sex skin, for example, an effect which 
would have been produced in these mon- 
keys by very small doses of estrone, was 
produced by progesterone if given in the 
large dose of 20 mg. daily. Growth of 
uterus and vagina, and vaginal cornifica- 
tion (all characteristic effects of estrogen) 
resulted from the treatment. Hormone- 
deprivation bleeding (experimental men- 
struation) followed discontinuance of 
treatment, just as it follows discontinuance 
of estrogen alone or of the estrogen-pro- 
gesterone sequence. Development of the 
mammary gland, with lobular prolifera- 
tion of the acini, occurred. The authors 
conclude that the specificity of action of 
the steroidal hormones is less than has 
heretofore been supposed. 

Estrogenic Hormones 

Dr. Hartman, with Dr. C. F. Geschick- 
ter, of Baltimore, has been treating rhesus 
monkeys with very large doses of estro- 
genic hormones over long periods of time. 
The chief results of these experiments, 
which were undertaken to study the rela- 
tion of the ovarian hormones to cancer 
and other tumors in the monkey, will be 
reported later. Meanwhile certain collat- 
eral results have been described from time 
to time. Drs. R. Tyslowitz and Hartman 
have followed the blood-cell count, reticu- 
locyte count, and hemoglobin level in some 
of these animals. No significant changes 
were found, nor anything to indicate a 
toxic effect of the large doses of estrogens. 



156 



CARNEGIE INSTITUTION OF WASHINGTON 



Dr. Hartman and Dr. Walter Fleisch- 
mann, of the Department of Pediatrics of 
the Johns Hopkins Medical School, have 
studied the amounts of cholesterol in the 
blood serum of rhesus monkeys. The mat- 
ter is of interest because of the similarity 
in molecular structure between the long- 
known steroidal substance cholesterol, 
which is a plentiful constituent of the ani- 
mal body, and the sex-gland hormones. At 
present the biological chemists do not 
know whether there is any functional re- 
lationship between these two groups of 
steroids. Hartman and Fleischmann found 
an average blood-serum cholesterol level 
of 120 mg. per cent in normal females at 
various times of the menstrual cycle, no 
mg. per cent in the first half of pregnancy, 
and 80 mg. per cent in the latter half of 
pregnancy. In 7 of the female monkeys 
mentioned above, which had received very 
intensive treatment with estrogenic hor- 
mones, the serum cholesterol was high, 
averaging 151 mg. per cent. 

Dr. Thomas R. Forbes, of the Depart- 
ment of Anatomy of the Johns Hopkins 
Medical School, published during the 
year a full report of his experiments on 
the absorption of pellets of crystalline hor- 
mones. A summary of this work was 
given in Year Book No. 40. 

Several years ago French investigators 
reported that the administration of one 
of the estrogenic hormones to rabbits 
caused, in certain cases, a change in hair 



color and loss of hair in symmetrical areas. 
In guinea pigs and also in human beings 
treatment with various estrogenic and an- 
drogenic hormones had sometimes been 
followed by changes in skin pigmenta- 
tion. In his rats which received pellets 
of ovarian steroid hormones, Dr. Forbes 
had an opportunity to make similar ob- 
servations. In albino rats he noticed par- 
tial pigmentation of the fur, and in a strain 
of dark gray-brown rats he observed alo- 
pecia (loss of hair) These results followed 
implantation of pellets of a large series of 
estrogenic hormones (of both the naturally 
occurring and the synthetic types) and 
their esters. Of the androgenic hormones, 
androsterone was active in this respect but 
not testosterone dipropionate. 

Reproduction in the Muskrat 

In connection with the Fish and Wild- 
life Service of the U. S. Department of 
the Interior, Dr. Forbes has sought to de- 
termine the breeding season of the musk- 
rat. Five hundred and sixty-two animals 
of both sexes were trapped in Maryland. 
Sections of the testes and ovaries indicate 
that in the males spermatogenesis begins 
about the middle of December and con- 
tinues until the following October. In 
the ovaries of the females corpora lutea 
appeared late in February, and similar evi- 
dence of ovulation was found until the end 
of October. 



SEX EDUCATION 



Our Department is primarily devoted 
to investigation of fundamental problems, 
and most of our work is not expected to 
find immediate application to human wel- 
fare. Dealing as we do, however, with 
embryology and the physiology of repro- 
duction, we are inevitably brought into 
contact with the human side of these 



subjects and see them in the light of our 
technical experience. It seems our duty 
to contribute from time to time to the in- 
struction of the public when there is op- 
portunity to do so through proper chan- 
nels. Such considerations impelled two of 
the staff to accept an invitation from the 
American Medical Association to contrib- 



DEPARTMENT OF EMBRYOLOGY 



157 



ute articles to a series on sex education. 
Dr. Corner's article, written in collabora- 
tion with Dr. C. E. Landis, of New York 
(bibliographic reference in Year Book No. 
40), dealt with sex education of adolescent 



boys and girls. Dr. Hartman dealt with 
information for the woman at menopause. 
Both articles were widely circulated in 
Hygeia, the Association's magazine for 
popular medical instruction. 



THE MAMMARY GLAND 



Action of Estrogenic Hormones 

While a student and intern at the Johns 
Hopkins Hospital, Dr. Harold Speert 
made an extensive study of mammary- 
gland problems. Many of the animals and 
notes of Dr. Hartman's monkey colony 
were put at his disposal for this purpose. 
Some of the results were mentioned in 
Year Book No. 40. 

One of Dr. Speert's experiments deals 
with the question as to how the estrogenic 
hormones act upon the mammary gland 
to make it grow. Certain experimental 
work in recent years has suggested the 
possibility that injected estrogens exert 
their effects through the pituitary gland. 
To test this question, Dr. Speert took ad- 
vantage of the fact that estrogenic hor- 
mones are absorbed through the skin. Us- 
ing immature male rhesus monkeys, he 
applied estrone in alcoholic solution to 
the left nipple, and alcohol alone to the 
right. In three such experiments the left 
mammary gland grew far more than the 
right. This result indicates that the action 
of the hormone was direct rather than 
through the pituitary gland, for otherwise 
a similar growth response of the two 
glands would be expected. It should be 
noted, however, that the experiment does 
not exclude the possibility of joint action 
of pituitary and estrogenic factors, as 
indicated by recent work of Turner and 
others. 

Cyclic Changes in the Mammary Gland 

In a preliminary report Dr. Speert dis- 
cusses the cyclic changes in the mammary 



gland. It has long been known that many 
women experience a sense of fullness and 
an increase in the size of the breast in 
the premenstrual phase of the cycle. Con- 
firmation and analysis of these changes 
by histological methods have, however, 
been difficult to secure, because of tech- 
nical difficulties in collecting and prepar- 
ing the material. The mammary gland 
of the rhesus monkey is much easier to 
study, and the material can be collected 
under experimental conditions. Dr. Speert 
subjected 9 monkeys, having regular men- 
strual cycles, to periodic biopsy of the 
mammary glands. Whole mounts or 
spreads of the gland tissue were made as 
well as sections. He found a definite series 
of cyclic changes in relation to the cycle. 
Beginning 7 to 10 days before the onset 
of the cycle, the lobules begin to enlarge 
and in some instances the individual acini 
are dilated. The blood capillaries become 
engorged. The changes attain their height 
at about the time of menstruation and 
slowly regress thereafter. They occur only 
in ovulatory cycles. 

Hysterectomy and the Mammary Gland 

There are certain indications, not always 
clearly defined, and evidently varying from 
species to species, that the uterus has some 
sort of influence (presumably endocrine) 
upon the corpus luteum and the mammary 
glands. In the guinea pig, for example, 
it appears that removal of the uterus when 
there are corpora lutea in the ovary causes 
persistence of corpora lutea and concomi- 
tant growth of the mammary glands. 



i 5 8 



CARNEGIE INSTITUTION OF WASHINGTON 



These effects have not been found in some 
other species. Dr. Speert observed a mon- 
key from which Dr. Hartman removed 
the uterus on the nth day of pregnancy. 
Biopsies of the mammary gland showed 
enlargement of the mammary lobules 5 
days later, at the time of the expected 
maximal corpus luteum effect. Sub- 
sequent biopsies revealed retrogressive 
changes during the 6 weeks after operation. 
In this one case, hysterectomy apparently 
failed to delay involution of the corpus 
luteum and had no effect on the mammary 
glands. 

Supernumerary Mammary Glands and 
Nipples 

In a careful review, Dr. Speert sum- 
marizes the literature on supernumerary 
mammary glands. These are relatively 
common in the human race, occurring in 
about 1 per cent of all individuals. Most 
of these accessory glands or nipples occur 
somewhere along the milk line, from 
axilla to groin. Their structure varies 
from an extremely rudimentary state to 
that of the typical breast. There is very 
little information about the condition in 
lower mammals, and Speert was able to 
find only eight reports of supernumerary 
nipples in apes and monkeys. To these 
he now adds 13 cases observed in approxi- 
mately 1000 rhesus monkeys which have 
been studied in the Carnegie colony. In- 
cluding one case previously reported by 
Hartman, the frequency of occurrence is 
about 1.4 per cent, which is within the 
order of frequency in the human species. 
In only 5 of these cases was glandular tis- 
sue associated with the accessory nipple. 
Supernumerary nipples were found sus- 
ceptible to stimulation by local application 
of estrogenic hormone. 



A guinea pig observed by Dr. Speert 
had an extra pair of accessory nipples. In 
this species such nipples are exceedingly 
rare. Single ones have been reported only 
twice, and an accessory pair only in one 
previous case. 

"Pale Epithelium" in the Mammary 
Gland 

Pathologists have been interested for 
many years in certain cells of the mam- 
mary gland, usually found lining mam- 
mary cysts. Because of their tendency to 
stain lightly as compared with the usual 
gland cells, these special cells are called 
"pale epithelium." They are generally 
found in the 4th and 5th decades of life. 
Their origin and their possible relation to 
cancer of the breast have been much dis- 
cussed. It is possible that more than one 
type of cell has been placed in this cate- 
gory. Recently experimenters have noticed 
the appearance of cells resembling the "pale 
epithelium" in rabbits and rats which had 
received long-continued treatment with es- 
trogenic hormones. Speert has now had an 
opportunity to study in this regard the 
mammary glands of Hartman and Ge- 
schickter's monkeys mentioned above, 
which received very intensive and long- 
continued treatment with estrone. In 4 
of 8 castrated animals and 1 of 7 intact 
monkeys thus treated, pale cells developed. 
They appeared at various times after the 
10th week of treatment. They most com- 
monly occurred in solid islets, rather than 
in cysts as in the human cases. Speert con- 
cludes that these cells arise from the mam- 
mary epithelium and represent a meta- 
plastic alteration of normal mammary- 
gland cells. Since none of these animals 
developed carcinoma, there is no support 
for any possible relation of the pale cells 
to the origin of malignant tumors. 



DEPARTMENT OF EMBRYOLOGY 



159 



CYTOLOGY 



Myelomatous Tumors 



Dr. Margaret Reed Lewis, of the De- 
partment's staff, is at present carrying on 
her work in the laboratories of the Wistar 
Institute of Anatomy and Biology in Phila- 
delphia. Working with Dr. G. B. Mider, 
of the National Cancer Institute, Dr. 
Lewis has recently been studying certain 
transmissible tumors of mice. These tu- 
mors are produced, as described by Mor- 
ton and Mider, by first treating mice 
of a dilute-brown strain by painting them 
with methylcholanthrene and afterward 
transplanting bits of the spleen, lymph 
node, or buffy coat of the blood of these 
mice into normal mice of the same strain. 
Myeloid tumors are thus induced. Lewis 
and Mider now find that such tumors may 
be transplanted serially into Bagg albino 
mice, in which they will grow, metastasize, 
and produce a general disturbance of the 
host animal just as in mice of the strain 
of origin (dilute brown). Up to 8 days 
after implantation the effects are indis- 
tinguishable. In the dilute-brown mice, 
however, the tumors progress until death 
of the animal, which occurs about the 12th 
day. In the majority of the Bagg albino 
mice, the tumors begin to regress after 
the 8th day, and within a few days the 
animals regain their normal health and 
appearance. Such mice are then immune 
against the growth of another implant of 
the same kind of tumor, but not to that of 
a sarcoma from the same or another strain. 
Here, then, is a very sharply defined, rap- 
idly detectable difference between two 
strains of animals with respect to suscepti- 
bility to tumor growth, which should 
furnish opportunity for investigation of the 
biological and chemical factors influencing 
the growth of tumor grafts. 

In another article Drs. Lewis and Mider 



discuss the identification of the cells of 
these tumors. In Year Book No. 39 men- 
tion was made of a new way of identifying 
the cells of the blood-forming organs, in- 
troduced by Dr. Lewis, by studying their 
mode of locomotion and their characteris- 
tics of form while moving, in motion pic- 
tures of living cells in tissue cultures. 
When this method was applied to the tu- 
mors induced by methylcholanthrene, it 
was found that their cells resembled those 
of myeloblasts and differed from lympho- 
blasts and mononuclear phagocytes. The 
tumors are therefore properly classified as 
myelomas. The authors had an opportu- 
nity also to study the cells of two cases of 
spontaneous leukocytosis arising in dilute- 
brown mice. These cells resembled leuco- 
cytes in characteristic form and motion. 

Studies on Living Spinal-Ganglion Cells 

About forty years ago the Strasbourg 
anatomist Bethe and the great Spanish 
histologist Ramon y Cajal brought the 
neurofibrils to the general attention of 
those interested in the nervous system. 
These are delicate threadlike strands, 
which in suitably stained preparations can 
be seen coursing in every direction through 
the cytoplasm of the nerve cells and pass- 
ing from the cell into the axone fiber and 
the dendrites. Their complexity and sharp 
definition, as seen in preparations by Ca- 
jal's method, have led many neurologists 
to think of them as the fundamental chan- 
nels of communication within the nervous 
system, like the individual wires in a tele- 
phone cable. On the other hand, the very 
existence of the neurofibrils has been de- 
nied, on the ground that they can be 
seen only after elaborate and somewhat 
drastic chemical treatment of nerve tis- 
sue. With the advent of the tissue -culture 



i6o 



CARNEGIE INSTITUTION OF WASHINGTON 



method, efforts have been made to see the 
neurofibrils in living, growing nerve fibers 
and nerve cells. Some observers have re- 
ported seeing them, others have announced 
their absence. 

Dr. Donal P. Murnaghan, who spent 
the year 1939-1940 in our laboratory as a 
traveling student of the National Uni- 
versity of Ireland, again took up this ques- 
tion. He was able to cultivate cells of 
the spinal ganglia of chick embryos and 
newborn mice and to study them while 
living, under high powers of the micro- 
scope. He was able also to visualize by 
vital staining the mitochondrial granules 
and "neutral red bodies" of the living cells. 



Murnaghan finds that neurofibrils are not 
visible in normal living cells in such cul- 
tures. Only when cells are suffering dam- 
age do fibrillar appearances become visible 
in the cytoplasm. He suggests that pos- 
sibly there is something existent but in- 
visible which becomes apparent in the 
moribund or nonliving cell under suitable 
conditions. He thinks that observers who 
have seen appearances resembling neuro- 
fibrils in living cells have been deceived by 
seeing the alignment of the mitochondria. 
The article is illustrated with very fine pho- 
tographs of the living ganglion cells, made 
by Mr. Reather from Dr. Murnaghan's 
preparations. 



THYROID AND ADRENAL GLANDS 



Enzyme Activity of the Colloid of the 
Thyroid Gland 

One of the oldest enigmas of histology 
has to do with the thyroid gland. This 
organ is composed of rounded chambers 
or follicles. Behind the cellular walls of 
each of the follicles lies a network of 
blood vessels. From these vessels the cells 
of the follicles receive the ingredients from 
which they elaborate a secretion in the 
form of a thick fluid (colloid), which is 
then stored in the cavity of the follicle. 
When needed by the body the colloidal 
material or its active ingredients must ob- 
viously be reabsorbed, back through the 
follicle lining into the blood stream. A 
major ingredient of the colloid is a protein 
of large molecular size, thyroglobulin; just 
how such material can pass through living 
tissue with apparent readiness becomes a 
question. It has been suggested, and in- 
deed actually demonstrated, that extracts 
of the thyroid gland contain a proteolytic 
enzyme which might catalyze the forma- 
tion and the hydrolysis of thyroglobulin, 
so that the passage both ways through 
the follicular wall would be effected by 



smaller molecular masses, which would 
afterward go in to be built up into thyro- 
globulin or come out from its hydrolytic 
breakdown. 

Dr. Eduardo de Robertis, of Buenos 
Aires, while working with Dr. Gersh in 
the Anatomical Laboratory of the Johns 
Hopkins Medical School on a Rockefeller 
fellowship, obtained further evidence con- 
cerning this question. He was able, by 
using microdissection pipettes, to withdraw 
droplets of colloid from individual fol- 
licles of anesthetized rats. Such droplets, 
placed on gelatine plates under proper 
conditions, were able to digest the gelatine. 
This demonstrates the existence of proteo- 
lytic ferment actually in the colloid. The 
colloid is an optically homogeneous viscous 
fluid, of slightly acid reaction (pH 6.6). 
After the administration of pituitary thy- 
rotropic hormone or of potassium iodide 
it becomes less viscous; but after a longer 
period of iodine administration the vis- 
cosity increases. The proteolytic enzyme 
gains activity in the acid range and loses 
it in the alkaline. Within the physiological 
pH range the activity increases after ad- 



DEPARTMENT OF EMBRYOLOGY 



161 



ministration of thyreotropic hormone and 
also temporarily after potassium iodide. 
The observations strongly support the hy- 
pothesis that an enzymatic mechanism is 
involved in the hydrolysis of the colloid 
protein and subsequent reabsorption of the 
products of hydrolysis. 

Blood Vessels of the Adrenal Gland 

The isolation of hormones from the cor- 
tex of the adrenal gland has caused re- 
newed interest in the anatomical struc- 
ture of this gland and particularly in its 
blood vessels. The classic description of 
the vessels of the dog's adrenal, published 
42 years ago by the late J. M. Flint, is 
limited to one species, and of course does 
not take into account modifications due 
to physiological states. Dr. I. Gersh, of 
the Department of Anatomy of the Johns 
Hopkins Medical School, and Dr. Arthur 
Grollman, formerly of the Department of 
Pharmacology, have studied the mouse and 
rat, using not only normal infant and adult 
animals, but also mice stimulated by low 
temperature and by thyroid extract to 
produce hypertrophy. They give a thor- 
ough and detailed account of the blood 



circulation in the adrenal glands of these 
animals as it varies with age and condi- 
tion. The most important point in their 
work is the demonstration that capillaries 
exist in the adrenal medulla (a fact which 
has been controverted so far as the mouse is 
concerned). The circulation through the 
cortex and that through the medulla seem 
to be distinct except that the blood from 
both drains into the medullary veins. This 
is an important matter because some have 
thought that the blood from the cortex 
passes through the capillaries of the me- 
dulla and can influence its function. 

The vessels of the X zone, which is 
peculiar to the mouse, are found to be 
loose-meshed, with few anastomoses. As 
would be expected, the capillary network 
becomes much richer when the X zone is 
made hypertrophic by experimental stimu- 
lation. Attention is called to the alteration 
of the capillaries of the fascicular zone 
from the irregular capillary bed seen in the 
embryo and in small accessory glands to 
the elaborately parallel pattern of the ma- 
ture gland, and an explanation of the final 
arrangement on the basis of physiological 
need is offered. 



GROSS AND COMPARATIVE ANATOMY 



The group of comparative anatomists 
in the Department of Anatomy of the 
Johns Hopkins Medical School, closely 
associated with the Carnegie Department 
of Embryology, has contributed this year 
a number of important articles on the 
anatomy of man, the other primates, and 
the vertebrates in general. 

The Femoral Trochanters 

Mr. A. Brazier Howell has discussed the 
homologies of the large bony processes or 
trochanters which characterize the head 
of the thighbone. There has been great 
difficulty in correlating the trochanters of 
14 



the various tetrapod vertebrates. Howell 
considers them from the standpoint of 
myology; that is to say, he regards the 
trochanters as associated with the attach- 
ment of muscle groups. The problem of 
correlating them thus becomes largely one 
of correlating homologous muscles. How- 
ell concludes that, in summary, the mam- 
malian lesser trochanter is a femoral group 
or iliopsoas process. The greater trochan- 
ter is a deep gluteal or partly peroneal 
group process with associated short flexor, 
chiefly tibial, elements around its margin 
and a superficial gluteal element either 
included or separate, in the latter case 



1 62 



CARNEGIE INSTITUTION OE WASHINGTON 



sometimes causing a third trochanter. The 
adductor tubercle is the fourth trochanter 
of mammals. An adductor process also 
occurs in some marsupials. 

The internal trochanter of Iguana is es- 
sentially a short flexor, largely tibial, and 
a deep gluteal or peroneal process. The 
faint process situated more laterally (dor- 
sally), or external trochanter, is a femoral 
or probably iliacus process. The fourth 
trochanter of some fossil reptiles is prob- 
ably a caudofemoral process. 

In modern birds, the large lateral tro- 
chanter represents a fusion of the elements 
of the mammalian greater and lesser tro- 
chanters, but without the element (super- 
ficial gluteal) of the mammalian third tro- 
chanter and with, in the fowl, the element 
of the fourth trochanter. When the last 
is well defined it is a caudofemoral process. 

The Shoulder of the Armadillo 

Dr. Samuel S. Miles, 1 working at the 
suggestion of Mr. Howell, has described 
very fully the shoulder musculature of 
the nine-banded armadillo of Texas, Dasy- 
pus novemcinctus texanus. The matter 
is of interest because the skeleton and 
muscles of the shoulder in this animal are 
highly adapted to the act of digging. The 
shoulder joint permits movement in the 
front-and-back direction much more amply 
than rotation or abduction. The scapula 
and humerus are formed in such a way 
as to allow strong attachments of the 
muscles giving leverage in the antero- 
posterior plane, and bringing about re- 
traction of the manus. For details of the 
musculature Dr. Miles' paper must be 
consulted. 

1 The author of this competent study was 
killed in action in the South Pacific area, 
August 1942, while serving as medical officer 
of the U. S. Navy, attached to the Marine Corps. 



A New Fascia of the Human Body 

The adult human body has been so 
thoroughly studied for hundreds of years, 
by anatomists prepared to detect the least 
novelty, that it is rare nowadays to have 
a new structure described. Dr. Ferdinand 
C. Lee, however, has called attention to 
a hitherto undescribed fascia situated be- 
tween the serratus anterior muscle and 
the chest wall. 

It was present to a greater or less degree 
in every one of the thirty bodies that 
were examined, being more evident in 
thin individuals, and being thickest near 
the inferior angle of the scapula. Micro- 
scopically, it is composed of connective- 
tissue fibers with a substantial interlacing 
of elastic tissue. The fascia, although pres- 
ent in a young chimpanzee, was absent in 
the ordinary laboratory animals. The func- 
tion of the fascia is probably to provide a 
protective surface for the motion of the 
scapula. 

The Homologies of the Forearm Flexors 

Probably no part of the body has been 
adapted, during the course of animal evo- 
lution, to as many different functional 
uses as the fore limb. For this reason its 
comparative anatomy, and especially the 
anatomy of its muscles, has been the object 
of much study and discussion. Dr. Wil- 
liam L. Straus, Jr., who recently published 
an elaborate analysis of the extensor mus- 
cles of the forearm, now presents a study 
of the forearm flexors in urodele am- 
phibians, reptiles, and mammals. The re- 
sults, which trace in detail the develop- 
ment of the individual muscles from their 
original matrices or common muscle 
masses, cannot be summarized instruc- 
tively here for the nonspecialist reader. 
The most interesting general point is that 
very few distinctively new muscles have 
been differentiated in the evolution of 



DEPARTMENT OF EMBRYOLOGY 



163 



reptiles and mammals; those present in 
these higher tetrapods can usually be rec- 
ognized, partially or fully differentiated, 
amid the muscle groups of the amphibians. 

The Locomotion of Gibbons 

The question of the way in which the 
apes use their hands in walking was dis- 
cussed in last year's report (Year Book 
No. 40) in connection with the studies 
of Dr. William L. Straus, Jr. It was 
pointed out that the gibbons, unlike the 
great apes, are able to extend their fingers 
when the palm of the hand is on the 
ground, so that they can assume the palmi- 
grade position when walking. The great 
apes, on the other hand, must walk on 
their knuckles, because they cannot ex- 
tend their fingers when in walking posi- 
tion. To what extent the gibbons actu- 
ally utilize their adaptability to the palmi- 
grade position has been questioned by 
Dr. Ales Hrdlicka, who reports gibbons 
that walked on their knuckles. Dr. Straus, 
in an interesting note, cites new evidence 
collected in the field by Dr. C. R. Carpen- 
ter. This shows that the mode of walking 
varies a good deal. The palmigrade pat- 
tern is among those actually used. An in- 
fant gibbon observed by Dr. S. L. Wash- 
burn also frequently placed its hands flat 
when walking. The present conclusion is 
that although adult gibbons seldom ac- 
tually use the forearms for support when 
walking, when they do, they sometimes 
walk on their palms, thus retaining a ca- 
pacity that has been lost by the great 
anthropoid apes. 

Relative Cranial Capacity in Primates 

The cranial capacity, i.e. the volume of 
the cranial cavity, furnishes a close indi- 
cation of the size of the brain, and is there- 
fore from the anatomist's standpoint one 
of the outstanding characteristics of a race 



of mankind or an animal species. In gen- 
eral, the larger the animal species, the 
smaller the relative size of the brain in 
proportion to the rest of the body. In any 
individual, moreover, the brain is relatively 
larger at birth than afterward. 

There has been a dearth of reliable in- 
formation about the relation between body 
weight and cranial capacity in the primates. 
In the case of many species, the number 
of specimens known to be normal and 
fully grown is small. Dr. Adolf H. 
Schultz, as part of his program of study 
of the physical characteristics and growth 
of the primates, has compiled the data on 
relative cranial capacity for 385 specimens 
of various species from marmoset to man. 
The marmosets rank lowest with respect 
to relative cranial capacity, followed in 
ascending order by the night monkeys 
(Aotus) and the howler monkeys (Alou- 
atta) and then by capuchin monkeys, ma- 
caques, guenons, langurs, and proboscis 
monkeys. The spider monkeys and gib- 
bons come next. All three great apes 
(chimpanzee, gorilla, orang) fit one curve 
which lies still higher on the scale, and 
the relative cranial capacity of man is at 
all ages far greater than that of any other 
primate. Dr. Schultz has been able to 
calculate the probable relative cranial ca- 
pacity of the fossil man Sinanthropus (Pe- 
king man) and finds that it must have 
been nearer to that of recent man than to 
that of any great ape of similar body 
weight. 

Observations on a Gorilla and an Orang 

Through the cooperation of Dr. J. F. 
Fulton, of Yale University, Dr. Schultz 
has had an opportunity to make morpho- 
logical observations on two adult female 
great apes of closely known age, the gorilla 
"Janet," formerly of the Bronx Zoo and 
more lately in the Yale colony, about 13 



164 



CARNEGIE INSTITUTION OF WASHINGTON 



years and 3 months old at the time of 
death, and the orang "Lulu," which was in 
the Yale colony from 1932 until her death 
in 1 941 at about 11 years and 4 months. 
Such dated specimens of the great apes 
are rare indeed. The description deals 
with many details, and a summary is dif- 
ficult. Taking what he has learned from 
these two animals into consideration along 
with other evidence, Dr. Schultz concludes 
that (1) the three great apes reach adult- 
hood at practically identical ages; (2) the 
permanent dentition is normally com- 
pleted in the eleventh year; (3) growth in 
general ceases, as a rule, between the ages 
of 10 and 12 years; (4) the last happen- 
ings in skeletal development are the ob- 
literation of most of the cranial sutures, 
the complete union of the clavicular epiph- 
ysis, and the final fusion of the bony rims 
at the iliac crest and at the lower angle of 
the shoulderblade. All this occurs gener- 
ally between the ages of 12 and 14 years. 
In all probability rules 2, 3, and 4 apply 
equally to chimpanzee, gorilla, and orang. 
In man, as is well known, these phases 
of maturation take place at very much 
more advanced ages. This fact must be 
regarded as a profound, though perhaps 
comparatively recent, evolutionary speciali- 
zation of man, which is unique among 
primates. 

The paper is illustrated with two skillful 
portraits of "Janet" from the pen of the 
author. 

Growth and Development of the 
Proboscis Monkey 

As a participant in the Asiatic Primate 
Expedition of 1937, organized by Mr. H. J. 
Coolidge, Jr., Dr. Schultz was able to col- 
lect 51 specimens of the proboscis monkey, 
Nasalis larvatus. A few other specimens 
have also been available to him. His meas- 



urements are recorded in a comprehensive 
paper which is an archive of data to be 
used later when the time comes for a gen- 
eral comparison of bodily proportions and 
growth in the primates. 

Included among the illustrations are 
three handsome plates by the late cele- 
brated medical illustrator Max Broedel, 
illustrating the facial appearance of this 



Growth and Development of the 
Orangutan 

In volume XXIX of the Carnegie "Con- 
tributions to Embryology" appears an ex- 
tensive monograph by Dr. Schultz on 
growth and development of the orangutan. 
This article sums up the work of many 
years. It has been compiled from a large 
number of specimens from various sources, 
including the Asiatic Primate Expedition 
of 1937, several museums, and other col- 
lections. Dr. Schultz has made a very 
large series of measurements and other 
morphological observations, from mid-fetal 
life to old age. The results provide a mine 
of information which will be of great use 
in formulating the laws of growth and 
bodily proportions in primates. The sum- 
mary alone comprises 3% pages of facts, 
and we can do no more here than cite a 
few items. 

Prenatal growth lasts 39 weeks. Post- 
natal growth appears to be completed 
sometime between the ages of 10 and 12 
years. The males grow to be much larger 
than the females, which average only 49 
per cent of the weight of the males (adult 
human females average about 81 per cent 
of the adult male weight). Female orang- 
utans, like humans, can become pregnant 
long before their second dentition is com- 
plete. The order of eruption of the teeth 
resembles that in the chimpanzee, differ- 



DEPARTMENT OF EMBRYOLOGY 



l6 5 



ing in many respects from that in man. 
Developmental anomalies of the perma- 
nent teeth and dental disease are very com- 
mon. Disturbances of the growth of the 
skeleton are also very common in wild 
orangutans, and all sorts of disease condi- 
tions are evident in the skeleton, including 
healed fractures, sinus infections, and 
arthritic joints. About one-third of all 
adult wild orangutans have had broken 
bones. 

It is as yet impossible to compare in 
detail the conditions of growth and devel- 
opment in orangutans with the correspond- 
ing conditions in many other primates. It 
can be concluded, however, that in general 
the ontogenetic processes of orangutan and 
chimpanzee are far more similar to each 
other than those of either of these species 
are to those of man. 

The interesting and valuable collection 
of pen drawings of heads of primates 
which have accumulated in the course of 
Dr. Schultz' studies is augmented in this 
article by three notable portraits drawn by 
the author, illustrating respectively an in- 
fant orangutan, an adult female, and an 
adult male. 

Relative Growth of Limbs and Tail 
in Macaque 

From an investigation on the anthro- 
poid apes, Dr. Hyman Lumer, of Fenn 
College, pointed out a few years ago that 
the relative growth of the limb bones con- 
forms to the law y = bx a , in which x and y 
represent two parts of the body and b 
and a are constants. Thus the plot of 
length of forearm, for example, against 
trunk length results in an exponential 
curve, and if these measurements are 
plotted logarithmically a straight line re- 
sults. 

From the data accumulated by Dr. 



Schultz, Dr. Lumer and he now study 
in the same way the growth of the limb 
segments and tail in several species of 
macaque. A striking point which comes 
out at once is that in the rhesus monkey, 
for which the investigators had fetal as 
well as postnatal material, there is a break 
in each of the relative growth curves they 
plotted, at a value of x corresponding 
roughly to the time of birth. 

Another point will be of great interest 
to those who are concerned with the dif- 
ficult matter of the classification of mon- 
keys. Bodily proportions are of course con- 
stantly used in distinguishing between 
closely related species. All the taxonomists 
have used the relative length of the tail, 
for example, as one of the means of dis- 
tinguishing between the rhesus and the 
Java macaques. Relative growth curves 
like those of Lumer and Schultz not only 
are more precise than mere measurement 
of individuals, but also take growth into 
consideration and thus utilize relative pro- 
portions at various ages, not in adults only. 
Curves thus obtained for the relative 
growth of the tail are different for each 
of six species studied, except that the point 
for Macaca irus, of which adults only were 
available, falls practically on the curve for 
M. sinicus. The authors thus tentatively 
conclude that the genus Macaca does not 
constitute a single tribe, but is divisible into 
several groups. The five tribes which they 
are thus able to demarcate correspond 
for the most part to the subgenera of the 
macaques set up by Elliot in his Review 
of the primates on the basis of conven- 
tional taxonometric methods. The authors 
suggest that their method, if it could be 
applied to a large number of specimens, 
might well yield valid taxonometric cate- 
gories and thus improve the groupings 
determined by naturalists on the basis of 
crude comparisons of bodily proportions. 



i66 



CARNEGIE INSTITUTION OF WASHINGTON 



THE NERVOUS SYSTEM 



Isolation of Part of the Spinal Cord 

Some years ago Dr. Sarah Tower found 
it possible to isolate a part of the spinal 
cord from incoming impulses, by trans- 
verse section at two levels and severance 
of the sensory roots between. These ex- 
periments, which were done on dogs, have 
now been confirmed in monkeys by Dr. 
Tower, with Drs. David Bodian and How- 
ard Howe, all of the Department of Anat- 
omy of the Johns Hopkins Medical School. 
In two out of three cases the isolated lum- 
bosacral cord survived the experimental 
trauma. By suitable staining, the investiga- 
tors obtained a picture of the intrinsic and 
motor mechanism of the cord, cleared of 
posterior root fibers and descending fibers. 
The reactions of the animals have con- 
firmed the conclusion reached after simi- 
lar study of isolated segments in dogs, that 
the mammalian cord mechanism operates 
only under the stimulus of arriving nerve 
impulses. Deprived of such excitation, the 
cord produces no activity which reaches 
effectiveness in the skeletal musculature. 



Fibrillation in Inactivated Muscle 

When a muscle is deprived of its nerve 
supply by cutting of the nerve, it atrophies. 
To this well known fact Dr. Tower added 
three years ago the new observation that 
such a muscle undergoes ceaseless minute 
contractions of its fibers or parts of the 
fibers, a process called technically fibrilla- 
tion, and continues in this peculiar state of 
activity for months, until atrophy sets in. 
The question now arises whether muscles 
made inactive by isolation of that part of 
the spinal cord by which they are sup- 
plied with motor fibers also undergo fibril- 
lation. In a monkey with isolated surviv- 
ing lumbosacral cord, the right sciatic 
nerve was cut. Muscles of the right thigh 
were therefore denervated, while those of 
the left thigh were inactivated without 
denervation. The former were found to 
fibrillate, the latter not. Atrophy de- 
veloping under conditions of inaction with- 
out denervation may therefore be con- 
sidered inactivation atrophy, or atrophy of 
disuse. 



BIBLIOGRAPHY 



Bodian, D. See Tower, S. 

Brewer, J. I. See Jones, H. O. 

Burns, R. K., Jr. The origin of the rete appa- 
ratus in the opossum. Science, vol. 94, pp. 
142-144 (1941). 

Corner, G. W. Corpus luteum hormone. Chap- 
ter 12 in Glandular physiology and therapy, 
a symposium prepared under the auspices of 
the Council on Pharmacology and Chemis- 
try of the American Medical Association. 
Chicago (1942). 

See Hartman, C. G. 

de Robertis, E. Proteolytic enzyme activity of 
colloid extracted from single follicles of the 
rat thyroid. Anat. Rec, vol. 80, pp. 219-231 
(1941). 

Fleischmann, W. See Hartman, C. G. 

Flexner, J. B., L. B. Flexner, and W. L. Straus, 
Jr. The oxygen consumption, cytochrome 
and cytochrome oxidase activity and histo- 



logical structure of the developing cerebral 
cortex of the fetal pig. Jour. Cell, and 
Comp. Physiol., vol. 18, pp. 355-368 (1941). 
Flexner, L. B., and A. Gellhorn. The com- 
parative physiology of placental transfer. 
Amer. Jour. Obstet. and Gynecol., vol. 43, 
pp. 965-974 (1942). 

and H. A. Pohl. The transfer of radio- 
active sodium across the placenta of the 
white rat. Jour. Cell, and Comp. Physiol., 
vol. 18, pp. 49-59 (1941). 

The transfer of radioactive so- 
dium across the placenta of the rabbit. 
Amer. Jour. Physiol., vol. 134, pp. 344-349 
(1941). 

See Flexner, J. B.; Gellhorn, A.; Pohl, 



H. A. 
Forbes, T. R. Absorption of pellets of crystalline 
testosterone, testosterone propionate, methyl 
testosterone, progesterone, desoxycortico- 



DEPARTMENT OF EMBRYOLOGY 



167 



sterone stilbestrol implanted in the rat. 
Endocrinology, vol. 29, pp. 70-76 (1941). 

Forbes, T. R. Instructions for collecting repro- 
ductive tracts of wild animals for study. 
U. S. Dept. Interior, Fish and Wildlife Ser- 
vice, Bull. 3-1486, July (1941). 

Sex hormones and hair changes in rats. 

Endocrinology, vol. 30, pp. 465-468 (1942). 
The period of gonadal activity in the 



Maryland muskrat. Science, vol. 95, pp. 382- 
383 (1942). 
Gellhorn, A., L. B. Flexner, and H. A. Pohl. 
The transfer of radioactive sodium across 
the placenta of the sow. Jour. Cell, and 
Comp. Physiol., vol. 18, pp. 393-400 (1941). 

See Flexner, L. B.; Pohl, H. A. 

Gersh, I., and A. Grollman. The vascular pat- 
tern of the adrenal gland of the mouse and 
rat and its physiological response to changes 
in glandular activity. Carnegie Inst. Wash. 
Pub. 525, Contrib. to Embryol., vol. 29, pp. 
111-125 (1941). 

Grollman, A. See Gersh, I. 

Hartman, C. G. Non-effect of ovariectomy on 
the twenty-fifth day of pregnancy in the 
rhesus monkey. Proc. Soc. Exper. Biol, and 
Med., vol. 48, pp. 221-223 ( I 94 1 )- 

Sex education for the woman at meno- 
pause. Hygeia, vol. 19, pp. 699-701, 747, 
756 (1941). 

and G. W. Corner. The first matura- 
tion division of the macaque ovum. Car- 
negie Inst. Wash. Pub. 525, Contrib. to 
Embryol., vol. 29, pp. 1-6 (1941). 

and W. Fleischmann. Serum cholesterol 

in the rhesus monkey. Endocrinology, vol. 
2 9, PP- 793-795 (i94i)- 

and H. Speert. Action of progesterone 

on the genital organs of the unprimed 
rhesus monkey. Endocrinology, vol. 29, pp. 
639-648 (1941). 

See Lewis, W. H.; Tyslowitz, R. 



Hertig, A. T., and J. Rock. Two human ova 
of the pre-villous stage, having an ovulation 
age of about eleven and twelve days re- 
spectively. Carnegie Inst. Wash. Pub. 525, 
Contrib. to Embryol., vol. 29, pp. 127-156 
(1941). 

Heuser, C. H., and G. L. Streeter. Develop- 
ment of the macaque embryo. Carnegie 
Inst. Wash. Pub. 525, Contrib. to Embryol., 
vol. 29, pp. 15-55 (i940- 

Howe, H. See Tower, S. 



Howell, A. B. The femoral trochanters. Field 
Mus. Nat. Hist., Papers on Mammalogy, 
Zool. Ser., vol. 27, pp. 279-291 (1941). 

Jones, H. O., and J. I. Brewer. A human em- 
bryo in the primitive-streak stage (Jones- 
Brewer ovum I). Carnegie Inst. Wash. Pub. 
525, Contrib. to Embryol., vol. 29, pp. 157- 
165 (1941). 

Krafka, J., Jr. The Torpin ovum, a presomite 
human embryo. Carnegie Inst. Wash. Pub. 
525, Contrib. to Embryol., vol. 29, pp. 167- 

193 (i94i)- 

Lee, F. C. Description of a fascia situated be- 
tween the serratus anterior muscle and the 
thorax. Anat. Rec, vol. 81, pp. 35-41 (1941). 

Lewis, M. R., and G. B. Mider. The identifica- 
tion of cells from induced and spontaneous 
leukoses of dilute brown mice. Jour. Nat. 
Cancer Inst., vol. 2, pp. 1 15-122 (1941). 

Spontaneous regression of mye- 
lomas and of their metastatic growths. Jour. 
Nat. Cancer Inst., vol. 2, pp. 123-125 (1941). 

Lewis, W. H., and C. G. Hartman. Tubal ova 
of the rhesus monkey. Carnegie Inst. Wash. 
Pub. 525, Contrib. to Embryol., vol. 29, 
pp. 7-14 (1941). 

Lumer, H., and A. H. Schultz. Relative growth 
of the limb segments and tail in macaques. 
Human Biol., vol. 13, pp. 283-305 (1941). 

Mider, G. B. See Lewis, M. R. 

Miles, S. S. The shoulder anatomy of the arma- 
dillo. Jour. Mammal, vol. 22, pp. 157-169 
(1941). 

Murnaghan, D. P. Studies on living spinal 
ganglion cells. Anat. Rec, vol. 81, pp. 183- 
203 (1941). 

Pohl, H. A., L. B. Flexner, and A. Gellhorn. 
The transfer of radioactive sodium across 
the placenta of the goat. Amer. Jour. 
Physiol., vol. 134, pp. 338-343 (1941). 

See Flexner, L. B.; Gellhorn, A. 

Rock, J. See Hertig, A. T. 

Schultz, A. H. Growth and development of 
the orang-utan. Carnegie Inst. Wash. Pub. 
525, Contrib. to Embryol., vol. 29, pp. 57- 
110 (1941). 

The relative size of the cranial capacity 

in primates. Amer. Jour. Phys. Anthropol., 
vol. 28, pp. 273-287 (1941). 

Growth and development of the pro- 
boscis monkey. Bull. Mus. Comp. Zool., 
vol. 89, no. 6, pp. 279-314 (1942). 

Morphological observations on a gorilla 

and an orang of closely known ages. Amer. 



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CARNEGIE INSTITUTION OF WASHINGTON 



Jour. Phys. Anthropol., vol. 29, no. 1, pp. 

1-21 (1942). 
Schultz, A. H. See Lumer, H. 
Speert, H. Mode of action of estrogens on the 

mammary gland. Science, vol. 92, pp. 461- 

462 (1940). 

Cyclic changes in the mammary gland 

of the rhesus monkey. Preliminary report. 
Surg., Gynecol, and Obstet., vol. 73, pp. 
388-390 (1941). 

Supernumerary mammae, with special 

reference to the rhesus monkey. Quart. Rev. 
Biol., vol. 17, pp. 59-68 (1942). 

Bilateral hyperthelia in a guinea pig. 

Anat. Rec, vol. 83, pp. 317-320 (1942). 

"Pale epithelium" in the mammary gland 

and its experimental production in the 
rhesus monkey. Surg., Gynecol, and Obstet., 
vol. 74, pp. 1098-1105 (1942). 

Non-effect of hysterectomy upon the 

mammary gland of the monkey. Endocri- 
nology, vol. 31, pp. 97-99 (1942). 

See Hartman, C. G. 



Straus, W. L., Jr. Notes: Locomotion of gib- 
bons. Amer. Jour. Phys. Anthropol., vol. 28, 
no. 3, suppl. (1941). 

The homologies of the forearm flexors: 

urodeles, lizards, mammals. Amer. Jour. 
Anat., vol. 70, pp. 281-316 (1942). 
See Flexner, J. B. 



Streeter, G. L. New data on embryogenesis in 
monkey and man. Trans, and Studies Coll. 
Physicians, Philadelphia, vol. 9, ser. 4, pp. 
71-85 (1941). 

See Heuser, C. H. 

Tower, S., D. Bodian, and H. Howe. Isolation 
of intrinsic and motor mechanism of the 
monkey's spinal cord. Fibrillation in skele- 
tal muscle in relation to denervation and 
to inactivation without denervation. Jour. 
Neurophysiol., vol. 5, pp. 388-401 (1941). 

Tyslowitz, R., and C. G. Hartman. Influence 
of large doses of estrogens on the blood pic- 
ture of rhesus monkeys (Macaca mulatto). 
Endocrinology, vol. 29, pp. 349-351 (1941). 



DEPARTMENT OF GENETICS 

Cold Spring Harbor, Long Island, New Yorf^ 
M. DEMEREC, Acting Director 



The first annual report of the present 
Acting Director may be an appropriate 
place for a short survey of the problems 
covered by the work of the Department of 
Genetics. The Department was organized 
almost forty years ago (1904), when the 
science of genetics was in its early in- 
fancy — was, in fact, still an unnamed child, 
with another two years to wait before ac- 
quiring its present name. In 1902, when 
the Carnegie Institution was incorporated, 
interest in the new science of heredity was 
running high; therefore, it is not at all 
surprising that the Trustees took under 
consideration the establishment of a labora- 
tory where work in the new field could be 
carried on. The first report of the Ad- 
visory Committee on Zoology includes the 
following statement: "As regards an ex- 
perimental station, among the most im- 
portant desiderata at present are experi- 
ments in heredity, in variation, in instincts, 
in modification, all of which should extend 
over a series of years and be planned sys- 
tematically" (Year Book No. 1 [1902], p. 
167). In addition, this first issue of the 
Year Book contains two memoranda writ- 
ten by prominent young biologists regard- 
ing plans for an experimental station for 
the study of heredity. One of these plans 
was accepted, and its author, Dr. C. B. 
Davenport, was appointed to take charge 
of the new laboratory. 

It was realized at the time the laboratory 
was founded that heredity furnishes a 
valuable clue to an understanding of the 
mechanisms of organic evolution. Ac- 
cordingly, the name "Station for Experi- 
mental Evolution" was given to the new 
division of the Institution. The young sci- 



ence of genetics was not ready, however, 
for an immediate attack on the problem 
of evolution. The phenomena of heredity 
constitute one of the most important at- 
tributes of living matter; and heredity may 
and should be investigated as a fundamen- 
tal physiological function, regardless of its 
bearing on organic evolution. Moreover, 
so far as the evolutionary implications of 
genetics are concerned, it took almost forty 
years to forge the concepts, experimental 
techniques, and quantitative methods with 
the aid of which a scientifically rigorous 
study of evolutionary changes could be 
undertaken. Finally, the heredity of man 
presents problems that require still dif- 
ferent methods for their solution, although 
it is becoming more and more evident 
that this study is a part of the larger field 
of evolutionary genetics. Shortly after the 
Eugenics Record Office was taken over by 
the Institution, the two laboratories were 
combined (1921) under the title Depart- 
ment of Genetics. 

Although the Station was organized by 
a zoologist, one of its first three staff mem- 
bers was a botanist. Thus, from the very 
beginning the work of the laboratory was 
arranged so as to break down the conven- 
tional dividing lines between sciences, and 
the new problems were attacked by the 
concentrated effort of representatives of 
several branches of science. This approach 
was, in a way, prophetic, for the present 
stage in the development of biology is 
characterized by a trend away from special- 
ization and toward a closer integration 
of biological disciplines. Such an attitude 
toward research is still one of the outstand- 
ing characteristics of this Department. 



169 



170 



CARNEGIE INSTITUTION OF WASHINGTON 



From the time the laboratory was or- 
ganized, the work with plants and that 
with animals have been carried on con- 
currently. When it soon became evident 
that for the solution of certain funda- 
mental problems the help of a chemist was 
essential, a chemist was added to the staff 
(1909); and when, later on, the problems 
under consideration branched out into the 
related field of physics, physical equip- 
ment was procured and the cooperation 
of physicists was enlisted. From its early 
days, problems of human heredity were 
included in the research program of this 
Department, and some of the most im- 
portant pioneering studies in that field 
were carried on here. The interests of the 
laboratory soon expanded far beyond its 
facilities, and as a consequence it has al- 
ways cooperated with other institutions 
in research on problems where such co- 
operation was advantageous. Cooperative 
work has increased with the growth of the 
Department, and today constitutes an im- 
portant part of its activity. 

The Carnegie Institution's interest in 
research on problems related to genetics 
did not stop with the establishment of 
this Department. A glance through the 
reports published in the Year Books will 
show that the research of many scientists 
working in this field has been furthered 
by the Institution's support. The list of 
Research Associates contains the names of 
W. E. Castle, E. B. Wilson, T. H. Morgan, 
C. B. Bridges, A. H. Sturtevant, C. E. Mc- 
Clung, R. Pearl, H. E. Crampton, E. B. 
Babcock, H. D. Goodale, L. R. Dice, F. B. 
Sumner, Th. Dobzhansky, and J. Schultz. 
A particularly strong measure of support 
was provided during those early days when 
genetics was in special need of recognition 
and assistance. This backing given to ge- 
netical research by the Institution undoubt- 
edly accounts to a large degree for the fact 



that the United States now occupies a lead- 
ing position in this branch of science. 

All along the line, this Department has 
made significant contributions toward the 
solution of current problems in genetics. 
Davenport's early work with poultry, ca- 
naries, and sheep, as well as on the inherit- 
ance of eye color and other characters in 
man, furnished classic examples of Men- 
delian inheritance; the work of G. H. 
Shull with Oenothera, Capsella, and Me- 
landrium, and particularly with maize, 
contributed fundamental knowledge which 
has greatly improved the methods of plant 
breeding; the pioneering research of C. C. 
Little opened up a road for experimental 
studies of the inheritance of cancer; and 
the brilliant work of the late John Belling 
laid the foundation for cytogenetics, and 
made possible the unique cytogenetic re- 
search carried on with Datura by Blakeslee 
and his group. MacDowell's studies of 
embryonic growth in mice, and Mac- 
Dowell and Potter's studies of leukemia in 
mice, are but two examples of painstak- 
ingly thorough research which has con- 
tributed much toward an understanding 
of these problems. New vistas in the en- 
docrine field have been opened up, and 
better understanding of the relation be- 
tween endocrines and heredity has been 
achieved, through the work of Riddle and 
his associates. C. W. Metz' studies with 
Sciara focused attention on a hereditary 
mechanism strikingly different from those 
usually found in other organisms; and the 
cytological research of Kaufmann, as well 
as the genetical and cytological work car- 
ried on by the gene group, has extended 
the sum of knowledge concerning the na- 
ture and action of genes. The statistical 
studies of the late Arthur J. Harris made a 
significant contribution to biometry; the 
work of A. M. Banta with Cladocera clari- 
fied the question of germinal and somatic 
variations in parthenogenetic animals; and 



DEPARTMENT OF GENETICS 



I 7 I 



the studies of Davenport and Steggerda 
have made an important contribution to 
our knowledge of growth in man. 

The development of genetics has been 
exceptionally rapid. At present, genetics 
is only a little more than forty years old — 
very young for a scientific discipline. But 
discoveries and spectacular events in this 
field follow each other in such rapid suc- 
cession that textbooks and reviews pub- 
lished only a few years ago are now hope- 
lessly outdated. New problems and new 
lines of approach are being discovered at 
a rate higher than that of the solution of 
the classic problems. With the passing of 
infancy and the onset of maturity of the 
science, the research methods used by 
geneticists are undergoing a rapid change. 
From the simple biological methods em- 
ployed at first, the experimental tech- 
nique has evolved into a complex struc- 
ture requiring the use of optical, physical, 
and chemical instruments. From the 
purely biological science of early days, ge- 
netics has developed into a science where 
cooperation with physics, chemistry, and 
mathematics is essential. 

One of the three fundamental groups 
of problems facing modern genetics to- 
day relates to the mechanism whereby 
hereditary characteristics are transmitted 
from parents to offspring. What is the 
chemical and physical structure of genes? 
how do they reproduce? how do changes 
in genes occur? what is the relation be- 
tween genes and chromosomes ? — these are 
but a few of the questions still waiting to 
be answered. These problems are being 
intensively studied at the Department, in 
cooperation with workers in a number of 
other institutions — particularly with Dr. 
A. Hollaender, biophysicist at the National 
Institute of Health, Bethesda, Maryland, 
and with a number of physics laboratories 
in New York City. 

The second cycle of problems concerns 



the action of genes in development. Why 
does a single cell, a fertilized ovum, de- 
velop into a complex organism, and how 
do the genes and chromosomes exert their 
determining influence on this process? 
Numerous attempts have been made to 
solve these problems, but so far all have 
failed for lack of fundamental informa- 
tion and reliable methods of approach. 
The work of MacDowell and Potter and 
of Riddle and his group is contributing 
this essential information. 

The third cycle of problems involves the 
processes of change within groups of or- 
ganisms (populations), which in a broad 
sense might be called organic evolution. 
It required almost forty years for genetics 
to accumulate information needed for 
work on this problem, and today the basic 
methods for the work are available. The 
Department, as now organized, is partici- 
pating in research on this problem, in 
close collaboration with Professor Th. 
Dobzhansky, of Columbia University, who 
is a Research Associate of the Institution. 

The field covered by genetics is so wide 
that research can most effectively be car- 
ried out through cooperation and close 
contact between various research groups. 
The location of this Department is ad- 
mirably suited to such cooperative arrange- 
ments. It is situated almost in the suburbs 
of New York, where there are numerous 
research establishments, and this enables 
the staff of the Department to participate 
in the scientific life of that city. At the 
same time it is sufficiently secluded to be 
attractive to scientists connected with uni- 
versities and colleges as a place to spend 
their vacations in congenial work. The 
Department has regularly a number of 
such summer guests, who furnish a stimu- 
lus to our research program. Two years 
ago, a closer collaboration was established 
with the neighboring Biological Labora- 
tory of the Long Island Biological Asso- 



I 7 2 



CARNEGIE INSTITUTION OF WASHINGTON 



ciation, and thus the opportunities for 
summer research have been greatly en- 
larged. Through the Symposia on Quanti- 
tative Biology, held yearly at the Biologi- 
cal Laboratory, we are now able to utilize 
a well established international conference 
for the discussion of problems in which our 
Department is interested. 

The past year has brought about sig- 
nificant changes in the Department. At the 
end of November 1941, its second director, 
Dr. A. F. Blakeslee, reached the retire- 
ment age and relinquished his post after 
twenty-six years of distinguished service 
as staff member, assistant director, and 
director. During this time Blakeslee en- 
joyed unequaled opportunities for research, 
which he utilized to the fullest extent. 
Under his leadership, genetical work with 
Datura has been developed, and outstand- 
ing discoveries have been made in many 
fields of genetics and cytogenetics. Blakes- 
lee and his co-workers remained with us 
until September 1942; he then transferred 
to Smith College, where he will be Wil- 
liam Allan Neilson Research Professor of 
Botany and continue with his investiga- 
tions as a Research Associate of the Car- 
negie Institution. 

During the past year the Department 
has been fortunate in having as a guest 
investigator Dr. Barbara McClintock, a 
well known research worker on the cyto- 
genetics of maize. Her stay here has in- 
vigorated our research program. 

As a result of close collaboration with 
the Biological Laboratory, a number of 
geneticists worked here during the sum- 
mer of 1942, making use of the facilities of 
the Laboratory and the advantages that 
our Department has to offer. In June a 
ten-day symposium on "The Relation of 
Hormones to Development" was held at 
the Biological Laboratory and was at- 
tended by over a hundred scientists. The 
program of this international conference 



was closely related to the work of the 
Department, and our members derived 
profit and stimulus from these meetings. 

A brief summary will be given here 
of the individual reports of the various re- 
search groups for the year ending Sep- 
tember 1, 1942; the reports in full are 
printed on the succeeding pages. 

Nearly six years of study of the role of 
hormones in the regulation of the maternal 
instinct in rats has been concluded and 
the results have been analyzed and pub- 
lished by Riddle, Lahr, and Bates. During 
embryonic life the hormones of the an- 
terior pituitary gland influence the growth 
and development of the sensorimotor 
mechanisms which are later capable of 
stimulation to sex drive or to maternal 
drive. In later stages of life the pituitary 
hormones have been found to provide the 
sequence of stimuli that results in un- 
learned maternal behavior. The sex drive, 
or its unexpressed foundations, is appar- 
ently a necessary precursor of the maternal 
instinct; and thus pituitary gonadotrophins 
play a part in the origin of the latter in- 
stinct, although their output is inhibited 
temporarily by the agencies that induce 
maternal behavior. Interrelations among 
hormones are such that, directly or in- 
directly and under suitable conditions, sev- 
eral of them promote the exhibition of the 
maternal drive; but the study produced 
much evidence that this instinct, which is 
the last to arise in the life cycle, is pro- 
voked primarily by prolactin. 

A type of prenatal loss that becomes se- 
lective for a given mutation only under 
certain conditions has been found by the 
group studying mouse genetics. Mice car- 
rying the screw-tail mutation reach birth as 
successfully as normals when the prenatal 
loss of normals is low, but as this increases 
the proportional loss of screw-tails is pro- 
gressively greater. This may provide an 



DEPARTMENT OF GENETICS 



173 



explanation of other defective ratios or 
irregular results. 

An excellent illustration of the manner 
in which a mutation can provide an in- 
terpretation of normal developmental proc- 
esses has been found in the case of the 
sternum of the screw-tail mouse, which is 
unique in lacking all signs of division into 
sternebrae. The conditions associated with 
the absence of segmentation of the sternum 
have provided a clue to the conditions re- 
sponsible for its presence. At the end of 
each rib a center of new growth is estab- 
lished in the early sternal material. In 
screw-tails the right and left members of a 
pair of these growth centers are so far apart 
that a continuous longitudinal band of 
fully matured cartilage runs the length of 
the sternum, before the first deposition of 
bone. In normals the right and left pairs 
of these growth centers are so close to- 
gether that they join, so that immature cells 
from one side meet immature cells from 
the other side, and divide the fully mature 
cartilage into a series of separate masses. 
This difference determines the presence 
or absence of segmentation, for bone can 
be deposited only in fully matured car- 
tilage. 

During the past year the gene group 
worked on a number of problems in which 
X rays, neutrons, ultraviolet and near infra- 
red rays, and chemicals were used to in- 
duce changes in genes and chromosomes 
and these changes were studied by geneti- 
cal and cytological methods. The mem- 
bers of the group collaborated with Drs. 
A. Hollaender and P. A. Cole, of the Na- 
tional Institute of Health, Bethesda, Mary- 
land, and with Dr. I. Gersh, of Johns Hop- 
kins University, in experiments with ultra- 
violet and infrared radiation; with Dr. 
S. Zamenhof, New York, in experiments 
with deuterium; and with the Columbia 
University cyclotron group, under the di- 



rection of Dr. J. R. Dunning, in experi- 
ments with neutrons. 

Over a period of eight years, data have 
been accumulating on the correlation be- 
tween genetic loci and the bands visible on 
salivary-gland chromosomes of Drosophila. 
This material has been summarized by 
Demerec and Sutton, and the positions of 
44 loci determined. In several instances, 
the position has been localized to a region 
covering only one band. Demerec has 
found a gene in the wild-type Swedish-b 
stock which increases the mutability of 
other genes. In collaboration with Zamen- 
hof, he has made an unsuccessful attempt 
to induce mutations with deuterium. Fano 
has completed the analysis of an interesting 
gene which when present in a female pre- 
vents hatching of about 80 per cent of the 
eggs laid by that female. 

The preliminary studies of Kaufmann, 
in collaboration with Hollaender, on the 
combined effects of X rays with the near 
infrared or ultraviolet radiation promise 
to furnish valuable data concerning the 
factors involved in chromosome breakage 
and recombination. The high degree of 
breakage and the great complexity of re- 
combination that may follow such treat- 
ment of Drosophila sperm is revealed in a 
rearrangement involving at least 32 points 
of breakage. 

The production by neutrons of domi- 
nant and recessive lethals is the object of 
an extensive new experiment being carried 
on by Fano. Previous reports, indicating 
that recoil protons have a good chance of 
producing more than one recessive lethal 
at a point where they hit, have not been 
confirmed. Neutrons seem to be more ef- 
ficient than X rays in producing lethals 
connected with chromosomal breaks; but 
they are less efficient in producing isolated 
recessive lethals appearing as gene muta- 
tions. This situation is contrary to the one 



i74 



CARNEGIE INSTITUTION OF WASHINGTON 



observed in ultraviolet experiments with 
both Drosophila and Neurospora, which 
show a lowered rate of chromosomal 
breaks as compared with gene mutations. 

Demerec, Hollaender, Houlahan, and 
Sansome undertook a comparative study 
of genetic effects produced on the fungus 
Neurospora by ultraviolet and X rays. Of 
the six wave lengths between 2280 and 
2967 A that were used, 2650 A was found 
to be most effective in producing muta- 
tions. It is of interest to note that nucleic 
acid has maximum absorption in this re- 
gion of the spectrum. In the case of X 
rays, the frequency of mutations increased 
with the dosage applied; in the case of 
ultraviolet radiation, the mutation rate in- 
creased up to a certain point and then de- 
creased. The "semilethal" type of mutant 
has been found very frequently among the 
changes produced by ultraviolet treat- 
ments, but has occurred rarely among the 
X-ray-induced mutants. The meaning of 
the observed differences between ultravio- 
let-treated and X-rayed material is being 
investigated. 

Brehme has completed the revision of the 
manuscript of the late Calvin B. Bridges 
on "The mutants of Drosophila melano- 
gaster," and has prepared it for publication. 

It has been known for a number of 
years that chromosomes may be broken by 
X rays, by a mechanical pull, or by some 
undetermined force. It has been known 
also that broken ends may fuse, thus pro- 
ducing various chromosomal aberrations, 
such as translocations, inversions, and de- 
ficiencies. Notwithstanding many efforts 
to discover them, however, the basic proc- 
esses responsible for the breakage -fusion 
event were not understood. Particularly 
puzzling was the question whether fusion 
occurs immediately after a chromosome 
is broken or whether a broken end may 
remain "unsaturated." A convincing an- 
swer to this question has been obtained 



by McClintock. She verified the unsatu- 
rated state of a recently broken end of a 
chromosome, when two nuclei, each of 
which had a chromosome with a broken 
end, were allowed to merge, and it was 
found that the two broken ends, derived 
from separate nuclei, could fuse. Simi- 
larly, she observed that when two recently 
broken ends enter a dividing nucleus, 
fusion may occur between these broken 
ends. When three recently broken ends 
are present in a nucleus, fusion may occur 
between two of the three ends. The third 
end "heals"; it permanently loses its un- 
saturated state, that is, its ability to fuse 
with any unsaturated broken end. Mc- 
Clintock likewise determined that even 
when two unsaturated broken ends are 
present in a nucleus, healing may some- 
times occur before union of the broken 
ends has taken place. Following this heal- 
ing, no fusions occur. 

Continued investigation by McClintock 
of the action of a progressive series of 
homozygous deficiencies of terminal seg- 
ments of the short arm of chromosome 9 of 
maize have shown that deficiencies up to 
and including the terminal third of this 
arm have very little effect on pollen de- 
velopment. Pollen grains with terminal 
deficiencies of a chromomere or less are 
completely functional. Those with longer 
deficiencies do not function. All the de- 
ficiencies studied can give viable and func- 
tional embryo sacs and eggs. Endosperms 
that are homozygous for small terminal 
deficiencies are normal. The seedlings, 
however, are modified: pale-yellow seed- 
lings occur when the homozygous defi- 
ciency is short, and white seedlings occur 
when it is slightly longer. The genetic 
behavior of these deficiency mutants is 
typically Mendelian. They are allelic, and 
dominance is an expression of the extent 
of the deficiency. A slightly longer homo- 
zygous deficiency causes early death of the 



DEPARTMENT OF GENETICS 



175 



embryo. The effects on endosperms of 
deficiencies longer than a terminal chro- 
momere were studied by means of the 
variegation method, utilizing the behavior 
of recently broken chromosomes. Endo- 
sperm development may be completely 
normal when a homozygous deficiency of 
two terminal chromomeres is present. Be- 
yond this region, only patches of homo- 
zygous deficient cells, surrounded by nor- 
mal cells, will develop. As the homozygous 
deficiency becomes progressively longer, 
the rate of development, the color of the 
aleurone, and the starch formation are 
progressively reduced except for the layer 
of cells immediately adjacent to normal 
cells. The cells in this layer appear to de- 
velop normally. This suggests that some 
diffusible substance or substances neces- 
sary for development are not produced by 
the homozygous deficient cells, but may be 
supplied by normally developing cells. 
The phenotypic effects of such large homo- 
zygous deficiencies are relatively mild. 
This could be understood if maize were 
a derived polyploid. 

Certain fundamental principles estab- 
lished in genetics can be applied directly 
to a number of problems met in breeding 
work with plants and animals. As a con- 
sequence of the emergency created by the 
war, the Bureau of Plant Industry of the 
U. S. Department of Agriculture acquired 
a large number of new plant-breeding 
projects which require a quick solution. In 
order to facilitate the work, parts of this 
new load were assigned to various labora- 
tories competent to handle them. Our 
Department was very glad to cooperate 
with the Bureau, and has taken up, 
through Warmke, several projects which 
it is well equipped to handle. These in- 
clude an attempt to produce a strain of 
fiber hemp with greatly reduced marihua- 
na content, and a cytogenetic analysis of 
the rubber-producing Russian dandelion. 



Warmke finds a wide variation in the drug 
content of individual hemp plants. This is 
encouraging as a starting point for selection 
and breeding experiments. The Russian 
dandelion is shown to be self-sterile and 
a basic diploid with normal sexual re- 
production. 

Working with Datura, Bergner has con- 
tinued her analysis of chromosomal 
changes that have occurred in the evolu- 
tion of that species; and Satina has made 
progress in her analysis of the develop- 
mental history of the various organs and 
the contributions of the three germ layers 
by means of periclinal chimeras. Avery 
has completed the tests on mutation rate in 
22- and 39-year-old seeds which had been 
stored under especially favorable condi- 
tions. He found that the rate is not so high 
in the old seed as in 10-year-old seed 
stored in the laboratory. 

Steggerda has continued with research 
in anthropology and human genetics. By 
comparing the measurements made on 
Navajo and Dutch children last year with 
those made in 1931-1934, he found a sig- 
nificant trend toward increase in weight 
and height among the children of today 
as compared with children of the same 
age group seven to ten years ago. A simi- 
lar trend has been observed by several 
scientists, but this is the first time that 
measurements have been made by the 
same person using a similar technique. 
Steggerda has completed the analysis of 
data involving measurements of 100 Negro 
men from Tuskegee Institute, and com- 
pared them with a similar set of data sup- 
plied by Professor H. H. Plough on white 
college students from Amherst. Although 
the weight for the two groups is approxi- 
mately the same, the Negro students are 
about one inch shorter. This is entirely ac- 
counted for by the shorter trunk of the 
Negroes, who also have broader shoulders 



176 



CARNEGIE INSTITUTION OF WASHINGTON 



and longer arms than the Amherst stu- 
dents. 

In order to compare anthropometric 
technique as used by various scientists, 
Steggerda had twenty-one investigators 
measure the same subject. The results of 
these measurements show considerable 
variation. These data constitute a starting 



point for the standardization of anthropo- 
metric technique. At the request of the 
Smithsonian Institution, Steggerda is mak- 
ing a survey of the known anthropometry 
of South American Indians. This study 
now includes data on more than 80 tribes, 
and covers the material contributed by 132 
investigations. 



DATURA STUDIES 

A. F. Blakeslee, A. G. Avery, A. D. Bergner, and S. Satina 



Evolution of Chromosomes in Nature 

Dr. Bergner has continued her analysis 
of the gross chromosomal changes that 
have occurred in the evolution of the 
herbaceous Datura species. In the past 
fourteen years it has been customary to 
study and to carry along concurrently 
many different cytological problems. This 
procedure has been necessitated by the 
fact that one obtains commonly only two 
generations per year. During the past year 
a few of those problems which were near- 
est completion were selected for completion 
if possible by the end of this year. 

Whenever necessary, technical "speed- 
ups" have been used. For instance, in 
order to determine the modified chromo- 
somes of prime type 96, tester races were 
crossed to heterozygous PT 96, since the 
latter has not yet been obtained in the 
homozygous condition. This necessitated 
looking at twice as many hybrids, since 
only a half of the gametes carried the modi- 
fied PT 96 chromosomes, but a year of 
time was saved. Also, in the cross of a 
heterozygous interchange from D. prui- 
nosa to D. jerox and to D. discolor and in 
intra se crosses of D. metel, the usual dor- 
mant period of seeds was eliminated by 
peeling off the outer seed coat of seeds 
as soon as they ripened, breaking the inner 
seed coat, and planting them immediately 
in soil. This process, although tedious and 



time-consuming, shortened the generation 
by two months. 

In the 1941 annual report, one of the 
natural prime types of D. stramonium (PT 
96) could not be included in the table be- 
cause the interchanged chromosomes had 
not been determined. They are 7 • 19 and 
8-20 instead of 7-8 and 19-20 of PT 1. 
This PT was obtained from a single race 
in Ohio and hence is included among the 
sporadic PT's. 

In the same table, three of the modi- 
fied chromosomes of D. pruinosa and 
of type 2 of D. leichhardtii were left 
blank. They have since been determined 
to be ii- 16, 12-22, and 15-21. This de- 
termination proved especially refractory 
because of the slight difference in size 
between the 15-21 and 12-22 chromo- 
somes, and because terminalization is com- 
plete at the • 21 end. Inconclusive evidence 
was furnished by crosses of a PT 3 from 
D. quercifolia and of D. stramonium PT 
91 with this interchange from D. pruinosa, 
which could be carried along only in the 
heterozygous condition. This necessitated 
crosses with D. jerox and D. discolor. It 
has not been possible to carry along this 
same interchange when extracted from 
type 2 of leichhardtii, but previous crosses 
between it and both pruinosa chromosomes 
and this particular interchange from prui- 
nosa have shown that, so far as the chro- 



DEPARTMENT OF GENETICS 



177 



mosome ends are concerned, the inter- 
change is identical in the two species. 
This conclusion is especially interesting 
since D. pruinosa is endemic in Mexico 
and D. leichhardtii in Australia. Since 
these two species are rather closely related 
in morphological characteristics, the geo- 
graphical location of their common an- 
cestor would be a matter of interest. 

As indicated in Year Book No. 40, D. 
inoxia will not cross directly with D. stra- 
monium but will cross with D. leichhard- 
tii; also it has been impossible to isolate 
the stramonium tester races in the homo- 
zygous condition, after repeated back- 
crosses onto D. leichhardtii, with the ex- 
ception of PT 9. Therefore, in making 
crosses to D. inoxia, it was decided to use 
these tester races when they are hetero- 
zygous, since half the offspring should 
carry the tester chromosomes. During 
the past winter heterozygous PT's 2, 3, 
7, 10, 17, 34, 40, 49, 61, 90, and 91 were 
obtained in plants which resemble D. leich- 
hardtii. These plants were kept alive dur- 
ing the spring and summer by grafting. 
They have been used as the female parents 
in crosses with three tester races of D. 
inoxia, Si's 115, 352, and 1080, and also in 
crosses with two tester races of D. mete- 
loides, Si's 121 and 948. It is hoped that 
at some time in the near future these seeds 
can be planted and the chromosomal con- 
figurations in the hybrids studied, so that 
the chromosomal end arrangements of the 
races of D. inoxia and D. meteloides can be 
determined. 

The seeds of many of these species 
crosses rarely germinate, and further dif- 
ficulty is encountered in the tendency to- 
ward asynapsis shown by D. inoxia (and 
to a lesser extent by D. meteloides) . Dur- 
ing the past year a few more hybrids were 
available for study, so that our knowledge 
is enlarged somewhat. In figure 1 of the 
last annual report (Year Book No. 40, p. 
15 



224), the chromosome arrangement in the 
cross between inoxia type 2 and homozy- 
gous PT 9 is incomplete. This has since 
been determined to be ©8 + ch8 + cri4'+ 
2 bivalents (©— circle; ch = chain). 
From the crosses of inoxia type 1 and type 
2 to stramonium PT 9 (20 -19-23 and -24 
chromosomes), 2 of their 12 chromosomes 
are now known to be the 19 • 20 and 23 • 24 
chromosomes. Therefore the end arrange- 
ments of these two are identical with two 
of stramonium PT 1. 

Also, a plant was obtained from the 
cross of extracted stramonium PT 1 to in- 
oxia type 3. It showed © 10 + ©4 + 5 bv. 
This ©10 indicated that the interchange 
between inoxia type 1 and type 3 involves 
1 chromosome from those 4 which induce 
a ©8 and 1 from 2 which induce a ©4 
with stramonium PT 1. 

Two species crosses which involve mete- 
loides type 1 were studied. The cross of 
meteloides type 1 to stramonium 11 • 16 + 
12-15 gave a hybrid which showed ©8 + 
©4+ ©4+ O4 + 2 bv. A cross to stra- 
monium PT 9 gave a hybrid which showed 
chio + ©4 + ©4 + ©4 + bv. The latter 
cross shows that the 23 • 24 chromosome is 
involved in the ©8 interchange, but the 
19-20 chromosome has ends identical with 
those of stramonium PT 1. 

A cross of meteloides type 2 to stramo- 
nium PT 9 showed a chi4 + ©4 + ©4 + 
bv. This type 2 also has a 19-20 chromo- 
some, whereas the 23 • 24 chromosome is 
involved in the postulated interchange of 
6 chromosomes (the cross of type 2 to other 
species has not yet been studied cytologi- 
cally). The chi4 further indicates that the 
interchange between meteloides type 1 and 
type 2 involves 1 chromosome from those 
4 which induce a © 8 and 1 from 2 which 
induce a ©4 with leichhardtii type 1. 

Although species crosses involving D. 
metel are limited to two rare crosses with 



178 



CARNEGIE INSTITUTION OF WASHINGTON 



D. meteloides and one with D. inoxia, 61 
races of D. metel have been used in intra se 
crosses. This species, which is widely dis- 
tributed in tropical and semitropical re- 
gions, has horticultural value because of the 
greater variety of flower color and double- 
ness of corolla. There is only one wide- 
spread chromosomal type, but four others 
have been distinguished. Correlation of 
these chromosomal types with flower color 
has disclosed geographical localization of 
the sporadic types. Completion of this 
study has been delayed by the slow mat- 
uration of D. metel in this latitude, many 
races requiring more than a full year before 
flowering. 

Periclinal Chimeras 

Miss Satina has made progress in her 
analysis of the developmental history of 
the various organs of Datura and the con- 
tributions of the three germ layers by 
means of periclinal chimeras. 

In 1941 detailed studies were begun in 
an attempt to analyze the structure of 
the carpel in Datura stramonium and to 
determine, by the use of periclinal chi- 
meras, the contribution of each germ layer 
to the development of the carpel. During 
the past year this work has been continued 
and is still in progress. At present it can 
be stated that the initiation and develop- 
ment of the various parts of the carpel 
(carpel wall, septum, false septum, and 
placenta) differ from those of the leaf, 
sepal, and petal. 

The initiation and development of the 
ovule during very early stages resemble 
those of the stamen and depend primarily 
on the activity of the innermost germ layer, 
L III. The cells of the middle germ layer, 
L II, form only the subepidermal layer. 
In later stages, the second layer becomes 
more active and contributes to the forma- 



tion of the nucellus from which the mega- 
spore mother cell differentiates. The in- 
tegument of the ovule is formed by the 
cells derived from the outermost germ 
layer, L I. The megaspore, and later the 
embryo sac, is covered by the tissue of the 
integument of epidermal origin, except at 
the chalazal end, which is formed by cells 
of the nucellus. 

Studies on incompatible 272 X 472 and 
472 X in crosses in Datura, which were be- 
gun in 1941 with the cooperation of Mrs. 
E. Sansome, were extended this year. For 
a better understanding of the processes ob- 
served and of the results obtained in the 
previous year, the crosses were made using 
as males 472 or in plants with the domi- 
nant gene Bz. Tetraploid Li and various 
types of periclinal chimeras with in egg 
cells (4/2 /\n in; in 472 in; in 472 \n; 
872 472 472) and with m egg cells (472 272 272) 
were used as females. The 472 X 272 crosses 
gave a larger number of seeds than the 
reciprocal crosses, but the germination of 
these seeds was poorer than in the 272 X 472 
crosses. Two hundred and twenty off- 
spring from 123 pedigrees were brought to 
maturity; 91 plants were offspring from 
the 472 5 X 272 cT crosses, 129 plants from 
the 272 2 X 472 cf- The offspring from the 
472 X 272 crosses were predominantly dip- 
loid (51 272, 23 372, 13 472, and 4 ?). The 
offspring from the 272 X 472 crosses were 
predominantly tetraploid (113 472, 2 372, 
3 272, and 11 ?). All but 4 of these off- 
spring, whether 272, 372, or 472, carried the 
Bz gene, and thus they presumably de- 
veloped from fertilized eggs. Further stud- 
ies are being made, and seeds have been 
collected for a survey of the next genera- 
tion to determine how much of the chro- 
mosomal constitution in each case was con- 
tributed by the male gamete which was 
tagged by a dominant gene. 



DEPARTMENT OF GENETICS 



179 



Mutations from Buried Seeds 

Among the various gene studies under 
way, perhaps the most interesting is that 
on the mutation rate from old seed, car- 
ried on by Mr. Avery. 

In 1933 it was shown by pollen-abortion 
records that the mutation rate in Datura 
was increased by the aging of seed stored 
under ordinary laboratory conditions. At 
that time it was shown that the percent- 
age of mutations found was roughly pro- 
portional to the age of the seeds from 
which the plants came. Seeds less than 1 
year old gave a mutation rate of less than 
1 per cent. The highest rate, 8.7 per cent, 
was obtained from seed that was from 
7 to 8 years old. Seeds stored under labora- 
tory conditions have failed to germinate 
when more than 10 years old. There 
seemed to be an increase of about 1 per 
cent for each year that the seed had been 
aged; thus, the rate of mutation obtained 
from seed 6 years old was 6.1 per cent. 
In the F 2 generation from these plants a 
total of 11 new visible types due to muta- 
tion was obtained. Mutations of types that 
show as visible morphological effects were 
about one-third as frequent as those that 
caused pollen abortion. The seed used in 
these experiments was of our highly in- 
bred Line 1. It has been repeatedly shown 
that the normal rate of mutation in this 
standard line of Datura is very low. 

In the summer of 1933 it was possible 
to obtain samples of soil from the unex- 
cavated parts of the cellar of a house built 
in Virginia 22 years previously. From 
these soil samples more than 500 Datura 
plants were obtained. Examinations of 
the pollen of these plants grown from seed 
that had apparently been buried for 22 
years in the soil revealed that the rate of 
mutation (1.8 per cent) was scarcely higher 
than that of the controls, and very much 
lower than that obtained from seed stored 



on the laboratory shelf for less than half 
as long. 

During the past year it has been possible 
to make a further study of the mutation 
rate from old seed. Through the kindness 
of Dr. E. H. Toole, of the U. S. Depart- 
ment of Agriculture, a quantity of Datura 
seed was obtained that had been buried 
in the open ground for a known length 
of time. In 1902, samples of a large variety 
of crop, flower, and weed seeds were buried 
in the soil near Washington, D. C. The 
seeds of Datura that went into this experi- 
ment had been collected from wild plants 
growing near the Potomac River near 
Washington. Each sample of seed was 
placed with soil in a small earthen flower 
pot and buried directly in the soil. At 
intervals of 5 or 10 years a few of each 
lot of seed had been removed and tested 
for germination by the Department of 
Agriculture. 

From Dr. Toole two lots of seed were 
obtained: one lot (A) of 188 seeds had 
been buried at a depth of 18 to 22 inches, 
the other (B) of 179 seeds had been buried 
from 36 to 42 inches below the surface. 
These seeds, with the surrounding soil, 
were sent to us in sealed metal containers. 
Upon arrival here the water content of A 
was found to be 7.15 per cent and that of 
B, 10.05. Although the seed was more 
than 39 years old, its germination was ex- 
ceedingly good. Lot A gave 182 seedlings, 
or 96.8 per cent, and B gave 176 seedlings, 
or 98.3 per cent. These plants were grown 
in the greenhouse during the past winter. 
The only recordable abnormality among 
the 356 plants that grew beyond the seed- 
ling stage was the frequent occurrence of 
large or small spots or flecks on the surface 
of the leaves. These spots were very clearly 
defined and were usually paler than the 
surrounding areas. Their exact nature 
has not yet been determined. 



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CARNEGIE INSTITUTION OF WASHINGTON 



The condition of the pollen of all of 
these plants was determined. Owing to the 
unreliability of pollen determinations made 
of plants grown in the greenhouse, it was 
impossible to establish a rate of mutation 
from the occurrence of plants showing 
high amounts of pollen abortion. Plants 
that genetically should have a low propor- 
tion of aborted pollen may show a high 
proportion of abortion when grown under 
greenhouse conditions, although plants 
with a genetically high proportion of abor- 
tion never have consistently normal pol- 
len. As there were very few plants that 
showed any abnormal pollen abortion, it 
was evident that there had been very little 
mutation causing pollen-abortion types. 

During the present summer F2 progenies 
have been grown from 78 of these plants 
from 39-year-old seed. Two of these 
showed segregation for pale-leaved types, 
and one segregated for a recumbent type 
called "lazy." In addition to these three 
new types, which were presumably 
brought about by recessive mutations, there 
was one progeny that segregated for a 
type somewhat resembling the in + 15-16 
primary. This also must be recorded as 
a gene type, since Dr. Bergner has deter- 
mined it to have the 2/2 number of 
chromosomes. 

The pollen of these F 2 plants was ex- 
amined as a further check against the 
possibility that pollen-abortion types may 
have been overlooked when the pollen de- 
terminations of the parents were made. 
None of the 78 cultures was found to seg- 
regate for individuals with a high percent- 
age of aborted pollen. In view of the fact 
that four new "visible" types were ob- 



tained, it is surprising that no pollen-abor- 
tion types were found, as in all previous 
experiments the pollen-abortion types have 
been more frequent than the visible types. 

From the 78 plants tested by F 2 prog- 
enies, there were recovered only these 
four mutations; this would be a rate of 
5.1 per cent. This is considerably higher 
than that obtained from controls, but is 
much lower than that obtained from seed 
"aged" under laboratory conditions. 

The low mutation rates obtained from 
the 39-year-old seed, as well as from those 
22 years old, indicate that age alone has 
little if any part in causing an increase 
in the rate of mutation in Datura. The 
high mutation rate apparent in plants 
grown from seed stored on the laboratory 
shelves was therefore probably brought 
about by other factors than age alone, prob- 
ably by the higher temperatures. Experi- 
ments conducted jointly with the Boyce 
Thompson Institute showed that Datura 
seeds held at various high temperatures 
(45 ° to 80 ° C.) for short periods (2 hours 
to 5 days) had a higher rate of mutation 
at the higher temperatures. Although no 
experimental data are available, it may be 
suggested that the probable reduction in 
the amount of oxygen surrounding the 
buried seed may also have played a part 
in keeping down the rate of mutation. 
Plants from either of the lots of buried 
seeds are not strictly comparable with those 
of our standard Line 1, which have been 
used as controls and which also came origi- 
nally from Washington. There is no evi- 
dence, however, that either of the "buried 
seed" races would be expected to differ 
from Line 1 in mutability. 



DEPARTMENT OF GENETICS 



IbT 



MAIZE GENETICS 

Barbara McClintock 



The Behavior of "Unsaturated" Broken 
Ends of Chromosomes 

In all cases involving rearrangements of 
segments of chromosomes which give rise 
to translocations, inversions, deficiencies, 
etc., it has been necessary to postulate 
some force that breaks a chromosome and 
some force that results in the permanent 
2-by-2 fusion of the broken ends. Previous 
investigations in maize on the mitotic be- 
havior of ring-shaped chromosomes had 
suggested that fusions may occur between 
two recently broken ends of chromosomes 
which enter the same nucleus. Such 
broken ends may be considered "unsatu- 
rated," i.e., capable of fusion with similar 
"unsaturated" broken ends, until fusion 
with another broken end occurs or until 
the end loses its capacity for fusion. To 
determine whether such an "unsaturated" 
state exists, male gametes containing a 
chromosome 9 whose short arm had been 
broken by mechanical pull at the previous 
anaphase were united with female gametes 
containing a similar recently broken chro- 
mosome 9. The zygote formed received 
from each gamete nucleus a single chro- 
mosome with a single recently broken end. 
On the basis of published data, these two 
recently broken ends, derived from sepa- 
rate nuclei, are believed to be in the "un- 
saturated" state and therefore capable of 
fusion with each other. If some force exists 
that brings these unsaturated ends to- 
gether and results in fusion, a dicentric 
chromosome should be produced com- 
posed of the chromosome 9 contributed 
by the female gamete and the chromosome 
9 contributed by the male gamete, fused 
at the ends of their short arms. Through 
the use of the endosperm markers / and C 
and through the aberrant mitotic behavior 



that reflects the presence of such broken 
chromosomes in the endosperm, it was 
possible to select the kernels from an ear 
whose zygote nucleus had received a chro- 
mosome with an unsaturated broken end 
from the male and female gamete nuclei, 
respectively. 

Out of a total of 18,243 kernels examined, 
20 non-germless kernels were obviously of 
the type desired. These kernels were ger- 
minated. If fusion had occurred between 
the broken ends of the chromosomes 9 
contributed by the two gametes, follow- 
ing chromosome reduplication, the dicen- 
tric chromosome should produce a double 
anaphase bridge configuration when the 
two centromeres of each chromatid passed 
to opposite poles. Breakage of the two 
bridges would result in the entrance into 
each nucleus of two newly derived, unsatu- 
rated broken ends. Fusion of unsaturated 
broken ends could occur in each sister 
telophase nucleus. Again, the two chro- 
mosomes 9 would be joined to form one 
chromosome with two centromeres. Re- 
peated anaphase bridge configurations 
should be expected to follow from such a 
chromosomal type of breakage-fusion- 
bridge cycle. Plants having such a dicen- 
tric chromosome and undergoing this cycle 
should have cells with various types of 
heterozygous and homozygous duplica- 
tions and deficiencies of the short arm of 
chromosome 9 following nonmedian break- 
ages of the anaphase bridges. Because of 
this process, the plants should be conspicu- 
ously modified in appearance. The plants 
arising from 10 of the 20 kernels were 
obviously of the type expected if a di- 
centric chromosome 9 were present. Ex- 
amination of the early roots confirmed the 
presence of a dicentric chromosome. Some- 



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CARNEGIE INSTITUTION OF WASHINGTON 



what less than one-half of the anaphase fig- 
ures showed contiguous double bridges. 
Owing to death or defective growth of 
many cells or sectors of tissue, 5 of these 
plants died in the seedling stage. Four of 
the remaining 5 plants continued to 
grow, because sectors of normal-appear- 
ing tissues developed. Gradually these 
sectors gained the ascendancy in growth, 
until the plant appeared quite normal. 
The fifth plant produced 3 normal shoots, 
which arose from the base of the de- 
cidedly aberrant and dying main shoot. 
Microsporocytes were obtained from the 
4 recovered plants and from 2 of the 3 
recovered shoots of the fifth plant. In 
all cases, pachytene analysis showed a 
bivalent chromosome 9. The two chromo- 
somes were not fused at the ends of their 
short arms. The two broken ends had 
healed in the ancestor cell which gave rise 
to the recovered sector. In most cases, the 
composition of the short arm of each mem- 
ber of the bivalent was greatly modified, 
although within a tassel sample all ex- 
amined sporocytes showed the same com- 
position for the individual member of the 
bivalent. In several of these plants, it was 
possible to determine the minimum num- 
ber of fusions, breakages, and bridges 
which must have occurred before healing 
of the two broken ends within a single 
nucleus had occurred. It is likewise known 
that the compositions of the short arms 
were entirely different in the sporocytes 
of the tassels of the 3 recovered shoots of 
the one original dicentric plant. The two 
chromosomes 9, however, had maintained 
their respective derived compositions with- 
in each shoot. This indicates that the mi- 
crosporocyte tissues of each shoot had 
originated from one individual cell whose 
cell ancestors had previously been under- 
going the chromosomal type of breakage- 
fusion-bridge cycle involving the original 
dicentric chromosome 9. The root system 



responded similarly. In the older roots of 
the surviving plants, no dicentric anaphase 
bridge configurations were observed. 

These experiments definitely show the 
existence of an "unsaturated" state of a 
recently broken end of a chromosome. 
Owing to causes as yet undetermined, 
however, such an end may become satu- 
rated (healed) without fusion. Following 
this, the end no longer takes part in any 
fusions. 

The remaining 10 of the original 20 
kernels classified as having received a 
broken chromosome 9 from each parent 
gave rise to 9 normal-appearing plants and 
1 pale-yellow plant which died in the 
seedling stage. None of these plants 
showed dicentric bridge configurations in 
the young roots. Examination of the sporo- 
cytes of the 9 surviving plants showed that 
4 had received a broken chromosome 9 
from each parent; but the morphology of 
the short arms gave no indication that 
fusions had occurred between these broken 
ends. In 1 plant one parent had con- 
tributed a broken chromosome 9, but it 
could not be determined whether the other 
parent had likewise contributed a broken 
chromosome 9. In the remaining 4 plants, 
each parent had contributed a broken 
chromosome 9, but one broken end had 
become saturated by fusion with a broken 
end other than that of the chromosome 9 
contributed by the second gamete and pos- 
sibly before fusion of the gametes them- 
selves. Consequently, healing of the 
broken end of the second chromosome 9 
had occurred. These results indicate that 
an unsaturated broken end produced by 
mechanical breakage of an anaphase 
bridge is capable of fusing with another 
unsaturated broken end arising from un- 
determined causes. 

A similar type of fusion has likewise 
been observed in sporocytes of 5 plants 
which were known to have been derived 



DEPARTMENT OF GENETICS 



183 



from a gametophyte which had received a 
chromosome 9 with an unsaturated broken 
end. It is known that mechanical pull 
caused by an anaphase bridge will fre- 
quently break a chromosome at a knob 
or at the centromere. In 2 of the 5 cases, 
the centromere of the broken chromosome 
9 was fused with the centromere of an- 
other chromosome of the complement. In 
one case, the fused chromosome was com- 
posed of the long arm of chromosome 9 
and the short arm of chromosome 2. In the 
second case, it was composed of the long 
arm of chromosome 9 and the short arm 
of chromosome 10. In each case, the com- 
plementary arm was missing. In three 
cases, the fusions had occurred at other 
positions than centromeres. In one case, 
a segment from the long arm of chromo- 
some 4 had united with the broken end of 
the short arm of chromosome 9. Since both 
chromosomes 4 in this plant were com- 
pletely normal, it is assumed that chroma- 
tid fusion in a gametophytic nucleus had 
occurred between the unsaturated broken 
end of chromosome 9 and a naturally aris- 
ing broken end terminating an acentric 
distal segment of chromosome 4. In the 
other two cases, both segments of the sec- 
ond broken chromosome were present. 
Pachytene analysis has led to the follow- 
ing interpretation: In the last two cases 
mentioned, a break occurred at one posi- 
tion in chromosomes 1 and 8, respectively. 
In both cases, this resulted in the presence 
of three unsaturated broken ends in the 
same nucleus, one of which was the 
broken end of the short arm of chromo- 
some 9. Fusion occurred between the un- 
saturated broken end of chromosome 9 and 
the unsaturated broken end of the acentric 
segment of the second broken chromo- 
some. This left the centric segment of the 
second broken chromosome with a single 
unsaturated broken end, which thereafter 
healed. This healing of a single un- 



saturated broken end, when introduced 
into sporophytic tissues, is in agreement 
with the results of similar investigations of 
this behavior. 

Phenotypic Effects of Homozygous De- 
ficiencies of Distal Segments of the 
Short Arm of Chromosome 9 

The phenotypic effects in male gameto- 
phytes, and in endosperm and sporophytic 
tissues, of a series of homozygous defi- 
ciencies involving distal segments of the 
short arm of chromosome 9 are being in- 
vestigated. These deficiencies were ob- 
tained through meiotic breakage of a di- 
centric chromatid 9 which had been pro- 
duced following crossing over involving a 
duplicated segment of the short arm of 
chromosome 9. This method has been 
previously described (McClintock, 1941; 
see bibliography). A number of terminal 
deficiencies have been isolated, ranging in 
length from a fraction of the terminal 
chromomere to deficiencies of approxi- 
mately one-third of the short arm, in- 
cluding the locus of C. At pachytene, the 
short arm of chromosome 9 has approxi- 
mately 20 chromomeres. Those in the 
proximal third of the arm are large, those 
in the distal two-thirds of the arm are 
small. 

The effect of homozygous deficiencies on 
the functioning of female gametophytes. 
Plants heterozygous for these deficiencies 
produce female gametophytes which are 
totally deficient for the respective seg- 
ments of chromosome 9. Complete func- 
tioning of such gametophytes occurs in all 
cases of short deficiencies. Only in the 
case of longer deficiencies which include 
4 or more chromomeres is there a reduc- 
tion in the functioning of such gameto- 
phytes. Environmental factors may be in- 
volved in this differential functioning. A 
preliminary test has indicated that, on a 
single ear, functioning of deficient female 



i8 4 



CARNEGIE INSTITUTION OF WASHINGTON 



gametophytes may be complete on one 
day and they may be totally nonfunctional 
on the succeeding day. Extensive tests are 
necessary to associate the effect with a par- 
ticular environmental condition. 

The effect of homozygous deficiencies on 
the appearance and functioning of male 
gametophytes. Plants heterozygous for 
these terminal deficiencies produce pollen 
grains one-half of which carry the deficient 
chromosome 9. In all cases, homozygous 
deficient pollen grains are completely filled 
with starch. Only in the case of deficiencies 
that include the distal one-third of the 
short arm is it possible to distinguish any 
perceptible differences in the appearance 
of the normal and the homozygous de- 
ficient grains. The latter grains appear to 
be smaller, but an exact identification of 
each grain has not been possible. Only in 
the case of distal deficiencies that are 
greater than one-third of the short arm 
is there a classifiable visible effect on pollen 
development. Some starch develops even 
in pollen grains that are deficient for 
nearly all of the short arm of chromo- 
some 9. 

Pollen grains that are deficient for small 
terminal segments are completely func- 
tional. Those deficient for more than the 
terminal chromomere, although completely 
normal in appearance, are nonfunctional. 

The phenotypic effects of small terminal 
deficiencies on endosperm and sporophytic 
tissues: the deficiency mutants "pale-yel- 
low" and "white" and their dominance re- 
lationships. Plants that are heterozygous 
for small terminal deficiencies produce via- 
ble and functional male and female ga- 
metophytes. These plants were selfed to 
determine whether viable endosperms and 
embryos that were homozygous for these 
deficiencies could be obtained. In 5 of the 
7 cases studied, the endosperm and embryo 
of kernels having the homozygous de- 
ficiencies were completely normal in ap- 



pearance. In 2 cases, some but not all of 
the embryos that were homozygous de- 
ficient had died before the maturity of the 
kernel. The endosperm of these kernels, 
however, was completely normal. In all 
5 cases with normal embryo development, 
pale-yellow seedlings, completely normal in 
gross morphology and growth rate, grew 
from these kernels. Although the coleop- 
tiles were light green, little chlorophyll 
developed in the leaves, and the seedlings 
died after exhaustion of the food reserves 
in the endosperm. The surviving embryos 
in the 2 cases where the homozygous de- 
ficiency resulted in early death of some 
embryos produced white seedlings com- 
pletely devoid of plastid pigments. Al- 
though the gross morphology of these 
seedlings was normal, the growth rate was 
considerably retarded. Proof of the asso- 
ciation of the pale-yellow and white seed- 
lings with the homozygous deficient state 
was obtained through cytological examina- 
tion of normal sibs, which had only homo- 
zygous normal and heterozygous deficient 
chromosomes; through crosses of these 
latter plants to plants heterozygous for 
longer deficiencies, where the mutant types 
appeared only from unions of the two re- 
spective deficient chromosomes; through 
close if not complete linkage with the mu- 
tant yg located near the end of the short 
arm of chromosome 9; and through chro- 
mosomal examination within white sectors 
of sectorial plants. 

Intercrosses among all 7 cases have 
shown that the 5 pale-yellow mutants are 
allelic and that the 2 white-seedling mu- 
tants are allelic to pale-yellow, with pale- 
yellow dominant to white. The 5 defi- 
ciencies giving rise to pale-yellow do not 
include the yg locus, whereas the 2 defi- 
ciencies giving rise to white seedlings may 
include this locus. The deficiencies giving 
rise to white seedlings are longer than 
those giving rise to pale-yellow seedlings, 



DEPARTMENT OF GENETICS 



185 



although they have a deficient segment in 
common. This accounts for the allelic na- 
ture of the two mutants and the dominance 
of pale-yellow over white. The pale -yellow 
and white mutants represent typical 
Mendelizing mutants, which are associated 
with a state of homozygous deficiency. 
Dominance in these cases is an expression 
of the extent of the deficiency: no defi- 
ciency produces green seedlings, a short 
terminal deficiency produces pale-yellow 
seedlings, and a longer terminal deficiency 
produces white seedlings, with dominance 
expressed in this order. 

The phenotypic effects of relatively long 
terminal homozygous deficiencies. Termi- 
nal deficiencies that include more than one 
chromomere do not give rise to functional 
pollen. Thus, the phenotypic effects of 
these deficiencies could not be studied by 
the direct method of selfing heterozygous 
plants. Instead, the variegation method, 
which produces sectors of tissue that are 
homozygous deficient, was introduced in 
these cases. This method utilizes the aber- 
rant mitotic behavior of recently broken 
chromosomes, which, in the endosperm, 
continuously deletes segments from the 
arm of the chromosome which has the 
broken end. If the female gametophyte 
contributed 2 deficient chromosomes, and 
the male gametophyte contributed a chro- 
mosome 9 whose short arm terminated in 
a recently broken end, the developing en- 
dosperm could be sectorial for homozygous 
deficient tissues. The endosperm mutants 
C (aleurone color), / (inhibitor of aleu- 
rone color, allelic and dominant to C), 
Sh (sh, shrunken endosperm), and Wx 
(wx, waxy starch) were used to mark the 
chromosomes contributed by the two par- 
ents. The preliminary investigations on 
the effects of homozygous deficiencies on 
endosperm development may be summa- 
rized as follows: Endosperm development 
may be completely normal when homozy- 



gous deficiencies up to and including two 
terminal chromomeres are present. Be- 
yond this region, only patches of such 
homozygous deficient tissue, surrounded 
by normal tissues, will develop. As the 
homozygous deficiency becomes progres- 
sively longer, the rate of development 
within the sector is reduced. Although 
the C locus may still be present, aleurone- 
color development progressively dimin- 
ishes until only the rim of cells bordering 
normal cells shows color. Apparently, 
some substance or substances diffuse from 
the normal cells into these homozygous 
deficient cells, allowing them to develop 
normal aleurone color. This material, how- 
ever, either does not diffuse beyond a layer 
several cells deep or is used up before 
deeper penetration occurs. Starch develop- 
ment occurs in all the patches of homo- 
zygous deficient cells except when the de- 
ficiency approaches the distal third of the 
short arm and includes the locus of C. 
In the latter case, relatively extensive 
growth of the homozygous deficient cells 
occurs; but, owing to lack of starch forma- 
tion in these cells, a shrinkage leading to 
scar formation occurs after drying of the 
kernels. 

To study the effects of various homozy- 
gous deficiencies on sporophytic tissues, 
the method of covering a deficiency with 
a ring-shaped chromosome may be utilized. 
Frequent losses of the ring-shaped chro- 
mosome during mitoses should produce 
cells that are homozygous deficient. Cells 
arising from these cells should produce 
sectors capable of expressing changes that 
could be related to the homozygous de- 
ficient state. Likewise, changes in consti- 
tution of ring chromosomes, which may 
delete segments from the ring, could pro- 
duce sectors that are homozygous deficient 
for various segments within the limits of 
the full deficiency. Only two such plants 



i86 



CARNEGIE INSTITUTION OF WASHINGTON 



have been produced. Both plants were 
characterized by numerous sectors of 
white, pale-yellow, and yellow-green tis- 
sues. Although these sectors probably rep- 
resent the expression of homozygous de- 
ficiencies, no conclusions will be drawn 
until this method receives more detailed 
and controlled analysis. 

A deficiency of one-third of the short 
arm of chromosome 9 is relatively long, 



but none of these deficiencies have been 
cell lethal in any of the tissues studied. 
It is altogether possible that the observed 
effects of the homozygous deficiencies in 
the various tissues may be related to a few 
specific loci within the limits of the distal 
third of the short arm, rather than to the 
accumulative effect of a large number of 
such loci. This would be understandable 
if maize were a derived polyploid. 



POLYPLOIDY INVESTIGATIONS 

H. E. Warmke 



The Marihuana Content of Hemp 

In addition to producing valuable fiber, 
hemp (Cannabis sativa) also produces the 
undesirable drug marihuana. With the 
huge plantings of this species throughout 
the nation necessitated by the interruption 
of fiber shipments from abroad, the prob- 
lem of control of this drug threatens to be- 
come a difficult one. For this reason, Drs. 
Barre and Robinson, of the Division of 
Cotton and Other Fiber Crops, Bureau of 
Plant Industry, U. S. Department of Agri- 
culture, suggested that the Department of 
Genetics help on a project started by them 
some time ago : that of producing a strain 
of hemp with materially reduced marihua- 
na content, if such is possible, by methods 
of selection and breeding. 

Several superior fiber strains were sup- 
plied, and have been tested for drug con- 
tent during the past season, using a modi- 
fication of the bio-assay method of Robin- 
son (1941). This method, as modified by 
the present workers, is based on the tox- 
icity to the fish Fundulus heteroclitus of 
different dilutions of acetone extracts of 
weighed samples of dry leaves, and has 
proved to be a completely practical method 
of marihuana assay. A series of four de- 
creasing dilutions, each containing 2 fish, 
is used to test each plant; and records are 



kept of the number of fish killed, the limits 
being fish killed for plants with low 
drug content and 8 fish killed for plants 
with extremely high drug content. Such 
an assay, of course, does not give absolute 
concentrations, but it does provide an esti- 
mate of the relative amounts of drug pres- 
ent in the series of plants being tested. 

Over 1000 marihuana determinations 
have been run during the course of the 
summer; results of tests on some 258 plants 
are given graphically in figure 1. It is of 
interest that the plants tested, although 
growing under as nearly identical condi- 
tions as possible, vary widely in marihua- 
na content. For example, 10 plants were 
found whose extracts failed to kill a single 
fish, even in the strongest concentration, 
and 1 plant was found which killed fish 
through all concentrations, including the 
most dilute. 

On the basis of dilutions used, this would 
represent an eightfold range in marihuana 
content, and is extremely encouraging as 
a starting point for selection and breeding 
experiments. If these differences are 
largely genetically controlled, by intercross- 
ing the plants on the left of figure 1 we 
should expect to obtain races in subsequent 
generations with greatly reduced average 
marihuana content. Of course, marihuana 



DEPARTMENT OF GENETICS 



187 



content is thought to be influenced by both 
genetic and environmental factors, and 
only further tests can show which of these 
factors is predominant in producing the 
array of potencies represented in figure 1. 
The data in figure 1 were regrouped so 
as to give a comparison of marihuana 
content of male and female plants. The 
116 females represented in this array killed 
an average of 3.5 fish per test, and the 86 




Fig. i. Relative marihuana concentrations in 
258 hemp plants as indicated by toxicity to fish 
of acetone extracts of dry leaves. Zero fish killed 
indicates plant with low toxicity; 8 fish killed 
indicates plant with high toxicity. 

males killed an average of 3.7 fish. These 
differences probably are not significant, 
and confirm the conclusions from previous 
limited chemical tests (Matchett and 
others, 1940) that no important sex differ- 
ence in marihuana content exists. 

Tests of single entire hemp leaves have 
shown an unmistakable gradient in alka- 
loid content extending from bottom to 
top of the plant. The bottom leaves have 
an extremely low alkaloid concentration, 
the top leaves a very high one. This find- 



ing called attention to the necessity of 
exercising caution in taking leaf samples 
for marihuana determinations, and eventu- 
ally led to the adoption of a method using 
the center leaflet from each leaf on the 
plant, rather than selected whole leaves 
as had been done previously. 

Polyploidy and Marihuana Content 

Marihuana determinations were also run 
on our original autopolyploid races of 
hemp in order to determine whether alka- 
loid content is affected by increase in chro- 
mosome number. These polyploid races, 
although not inbred, were all derived 
from the same original diploid strain, and 
therefore have a comparable genetic back- 
ground. 

The results of these tests, based on deter- 
minations from 25 plants for each mem- 
ber of the series, are as follows: 

„, , - , Average no. 

P ° lypl0ld fish killed 

Diploid 1.4 

Triploid 3.0 

Tetraploid 2.6 

This indicates a definite increase in mari- 
huana content in the triploid and tetra- 
ploid races, which of course could not have 
been predicted in advance. 

A similar increase in vitamin C content 
in autotetraploid tomatoes has been re- 
ported by Sansome and Zilva (1933); and 
Randolph and Hand have recently found 
an increased concentration of vitamin A 
in autotetraploid corn. Cases of this na- 
ture, where the autopolyploid produces a 
chemical product in a different concentra- 
tion from its related diploid, are beginning 
to be noted; these throw important light 
on the mechanism of gene balance and 
action. 

The slightly greater drug content in trip- 
loids than in tetraploids in these tests 



i88 



CARNEGIE INSTITUTION OF WASHINGTON 



is out of line in the polyploid series. 
Whether this difference will be borne out 
with more extensive testing is not known; 
it was found consistently, however, among 
the plants in this series of tests. 

Before these marihuana determinations 
on polyploids were made, samples of seed 
of our established diploid and tetraploid 
races had been submitted to the Depart- 
ment of Agriculture for comparative tests 
of fiber quality and quantity. The robust 
habit of the tetraploid had suggested a 
possible superiority in fiber content. It 
would now appear that the tetraploid race 
will be less desirable than the diploid from 
the standpoint of drug content; final judg- 
ment on its over-all value, however, must 
await the results of the fiber tests now in 
progress. 

The Russian Dandelion 

In May 1942, Dr. E. W. Brandes, in 
charge of special rubber investigations of 
the Bureau of Plant Industry, requested 
the Department to undertake a cytogenetic 
study of the rubber-bearing Russian dande- 
lion {Taraxacum \o\-saghyz). The pur- 
pose of the investigation was to ascertain 
the chromosome number and reproductive 
behavior, in order to lay a foundation for 
the intelligent growing and breeding of 
this species in America. Some 2000 plants 
have been grown in the greenhouses and 
out of doors during the past season. A suf- 
ficient number of these have come into 
flower so that certain findings can be re- 
ported at this time. These findings gen- 
erally are in agreement with those of the 
Russian workers Poddubnaja-Arnoldi and 
Dianowa. 

Taraxacum \o\-saghyz is a basic diploid 
in the genus, with a chromosome number 
of n — 8; 27z = 16, at least one pair of which 
bear satellites. Those plants that have 
reached the flowering stage to date fail to 



set seed when isolated in the greenhouses, 
but set seed abundantly out of doors or 
when manually cross-pollinated in the 
greenhouse. This indicates the species to 
be self-sterile, but fully cross-fertile. 

Studies now in progress indicate that 
gamete formation is normal on both the 
male and female sides. The formation of 
the female gamete, which is often abnor- 
mal in the common species of dandelion, 
leading to the parthenogenetic develop- 
ment of an unreduced egg cell, appears 
to follow the normal sexual pattern in 
T. \o\-saghyz. The archesporial cell en- 
larges and undergoes a normal meiosis to 
form a linear series of 4 reduced 
megaspores, the chalazal one of which 
develops into a normal 8-celled embryo 
sac. 

These conditions are extremely fortu- 
nate from a practical point of view, be- 
cause they make selecting and breeding 
experiments possible. Since T. \o\-saghyz 
is a member of the Compositae, experi- 
mental breeding would have been ex- 
tremely difficult had it proved self-fertile 
or parthenogenetic. 

Several hundred colchicine-treated plants 
are also being grown in an effort to ob- 
tain a tetraploid race. On the chance that 
the tetraploid might show altered, and 
possibly desirable, rubber-producing quali- 
ties, it seemed of value to treat a group 
of plants. Many of these have been mark- 
edly affected by the treatment, as indicated 
by rough and thick leaves. Pollen-size de- 
terminations of four treated plants that 
are now in flower show one to be tetra- 
ploid; so it is hoped that a tetraploid race 
may be established sometime this winter. 

The Sex Mechanism in Silene otites 

Silene otites is a dioecious plant, but 
whether the male or female is heteroga- 
metic (XY) cannot be determined by cy- 



DEPARTMENT OF GENETICS 



189 



tological methods, because of similarity 
in size of the sex chromosomes. Sansome 
(1938) has reported the female to be heter- 
ogametic on the basis of indirect evidence 
obtained from interspecific hybrids. By 
doubling the chromosome number in this 
species and utilizing the peculiar breeding 
behavior of the 4/2 sex heterozygote, it 
has been possible to present extremely 
good evidence to the contrary: that the 
male is XY. 

The method is as follows : Using colchi- 
cine, XX and XY plants are transformed 
into XXXX and XXYY plants, respec- 
tively. The XXXX individuals will pro- 
duce only XX gametes, but the XXYY in- 
dividuals will produce at least 1 XX : 4 
XY : 1 YY gametes. A higher proportion 
of XY gametes will result if differentiation 
of the sex chromosomes is sufficient to dis- 
turb random pairing. When XXXX and 
XXYY individuals are crossed, therefore, 
three types of offspring are expected: 1 
XXXX: 4 XXXY: 1 XXYY. In Silene, ap- 
proximately 5 males to 1 female are ob- 
tained when treated /\n males and females 
are crossed, which indicates two classes 
of males: 1 XXYY and 4 XXXY, or 1 
XXXX and 4 XXXY, depending upon 
whether the female is XXXX or XXYY. 
To determine the constitution of the fe- 
male, several of the treated qn females are 
crossed to diploid males (and reciprocal if 
possible). If the female is XXXX, a 372 
population of 1 male to 1 female should 
result; if it is XXYY, 5 males to 1 female 
would be expected. In Silene this cross 
has produced triploid males and females 
in a ratio that does not deviate significantly 
from 1:1. This indicates that females are 



homogametic and males are heterogametic, 
and makes possible the interpretation of 
breeding results on the same basis as in 
Melandrium. 

Further evidence is being sought by in- 
tercrossing tetraploid males and females 
from 1 : 1 pedigrees. If the above explana- 
tion is correct, these should give only 1 : 1 
populations; if it is incorrect, ratios other 
than 1 : 1 should be observed. It seems 
likely that these methods may find wide 
application in determining the hetero- 
gametic sex in species other than S. otites. 

A Gynodioecious Race in Melandrium 

One of the results of the inbreeding 
program being carried on with Melan- 
drium (Year Books Nos. 39 and 40) is 
the establishment of a diploid race con- 
sisting of XX females and XY male-her- 
maphrodites. This race arose by the re- 
covery of XX and XY types from the self 
of selected strongly female XXY types. 

When these XX and XY types are 
crossed, females and male-hermaphrodites 
appear in approximately a 1 : 1 ratio. The 
XY male -hermaphrodites, when selfed, 
produce females and male-hermaphrodites 
in the ratio of approximately 1 : 3 (10: 33). 
The securing of selfed offspring from the 
XY plants was of extreme interest because 
it afforded an opportunity to obtain YY 
individuals, a type reported in some other 
species but never in Melandrium. The cy- 
tological analysis of 26 of the male types 
from these pedigrees, however, has shown 
only plants with X and Y chromosomes, 
which probably indicates the YY type to 
be inviable. 



190 



CARNEGIE INSTITUTION OF WASHINGTON 



THE GENE 

M. Demerec, B. P. Kaufmann, U. Fano, Eileen Sutton, and Eva R. Sansome 



Gene Position and Action 

A gene increasing mutability. It was 
noted in various experiments conducted by 
Dr. Demerec that X-chromosome lethals 
originated with much higher frequency 
in certain males from the wild-type Swed- 
ish-b stock than in their brothers. Further 
tests indicated that such males contain a 
gene that increases the rate of mutability 
of other genes. Experiments are now un- 
der way to isolate this gene and to study its 
behavior. It appears that this mutability 
gene is similar to the one found earlier in 
the wild-type Florida stock and described 
in Year Book No. 35 (1935-1936), pages 

43-45- 

Semisterility genes in Drosophila. At- 
tempts to investigate and reduce the steril- 
ity of untreated Drosophila material, in 
order to improve the conditions for accu- 
rate measurement of dominant lethals, 
were reported in Year Book No. 40 by Dr. 
Fano. These attempts resulted in the iso- 
lation from Swedish-b stock of a new re- 
cessive semisterility character, located in 
the second chromosome and effective only 
in females. A majority of the eggs laid 
by females that are semisterile (ssi) fails 
to hatch. Counts of the offspring of 27 sst 
females showed that the proportion of eggs 
hatching varied between 12 per cent and 
52 per cent. Genetic characters inducing 
complete sterility have frequently been 
reported in the literature, but the new 
character described here seems to belong 
to a less well recognized type. It might 
have been expected that the constitutional 
characteristics of a female affecting the de- 
gree of viability of its offspring would be 
determined by the collective action of a 
large number of factors, each of them only 
slightly important in itself. The identifica- 



tion of the factor sst indicates that this is 
not so. This one character brings about 
very striking effects; but the experiments 
indicate that weaker characters having 
analogous effects are so widespread among 
laboratory stocks as to make it difficult to 
isolate high-fertility strains. 

Cytogenetic analysis of the Bar locus. 
The analysis of our stocks of Bar, double- 
Bar, and double infra-Bar confirmed 
Bridges' (1935) cytological analysis of the 
first two, and showed no detectable differ- 
ence between double-Bar and double infra- 
Bar. 

Twenty-nine changes at the Bar locus 
(changes from wild-type to Bar, from Bar 
to or toward wild-type, and from double- 
Bar and double infra-Bar to or toward 
wild-type) have been analyzed cytologi- 
cally and genetically by Dr. Sutton. 

The Bar locus appears to be associated 
with the band 16A1 • 2 of the salivary- 
gland X chromosome, and the Bar pheno- 
type is produced by a limited number of 
the possible rearrangements in which this 
locus is brought into immediate contact 
with loci in other parts of the chromo- 
somes. The Bar effect is thus a position 
effect, and is not essentially different from 
other known position effects. In no case 
has the Bar effect been produced by mu- 
tation of the Bar locus without rearrange- 
ment, but reversions of Bar to normal can 
be brought about by mutation or inactiva- 
tion of the Bar locus or the adjacent inter- 
acting locus. In the original Bar stock the 
position effect seems to be produced by 
the contiguity of the bands 16A1 • 2 and 
16A7, and in double-Bar and double infra- 
Bar this association of bands is duplicated. 
Complete reversions of double-Bar or 
double infra-Bar to wild-type have been 



DEPARTMENT OF GENETICS 



191 



obtained by irradiation, without any visible 
change in the chromosomes, and these 
phenotypic changes must be due to simul- 
taneous inactivation of both associations 
of the interacting loci. 

Location of genes in the salivary-gland 
X chromosome. Over a period of eight 
years, all spontaneous and induced changes 
obtained in loci in the X chromosome have 
been analyzed both genetically and cyto- 
logically. The genetic tests determined all 
loci affected in each case, and the cytologi- 
cal analysis of salivary-gland chromosomes 
determined what chromosomal aberrations, 
if any, were associated with the genetic 
changes. The accumulated data have made 
it possible to correlate particular genes with 
single bands or strictly delimited regions 
of the salivary-gland X chromosome. The 
following genes have been located in this 
way: y and ac (1A5-8), sc (163-4), svr 
(iB5,6), M(i)Bld (iBii-iC2-3), sta, tw, 
and br (1C4 -5-2010), pn (21)5,6), \z 
(2Ei-2-2F6), w (302-3), rst (3C4), N 
(3C7), dm (3D1.2), M(i) 3 E (3E3.4), 
ec (3Fi-2), M(i)4BC ( 4 B5-4C5-6), bi, 
peb, and rb (4C7 • 8-4D1 -2), rg (4E1-3), 
ex and cv (4F1 -2~5Di -2), rux and vs 
(5D3 -4~6Ai -2), dx, shf, scp, and cm 
(6A3 • 4-6F10 • 11), ct (7B34), sn, oc, ptg, 
dd, tbd, and con (7C4 • 5-8C1 • 2), t and Iz 
(8C3-17), dvr (to right of 8D8-9), m 
(10C3 • 4-E1 -2), dy (to right of 10E1 • 2), 
M(i)o (15B1.2-E7), / (15F1-5), B 
(i6Ai- 2 ). 

Mutants of Drosophila melanogaster. 
The compilation of descriptions of the mu- 
tants of Drosophila melanogaster made by 
Dr. C. B. Bridges and printed in first draft 
in 1938 as Drosophila Information Service 
No. 9 has been completed and edited by 
Dr. Katherine S. Brehme, and is to be en- 
titled "The mutants of Drosophila melano- 
gaster." In preparing the first draft, Dr. 
Bridges utilized the mutation list which 
he had maintained and continually revised 



since 1914, and which included the data 
concerning all significant mutations and 
reoccurrences found by him and other 
members of the laboratory of Dr. T. H. 
Morgan. He also used the information 
published in the Carnegie monographs and 
in Drosophila Information Service Nos. 
1-8. Special contributions of new data 
were made by a number of investigators. 
After the death of Dr. Bridges, a system- 
atic survey of the literature was made by 
Dr. Brehme, covering all available publi- 
cations on the genetics of Drosophila 
through August 1942. An attempt was 
made to include such information concern- 
ing the mutations as would be of use to 
investigators, and to document all data 
as thoroughly as possible. Each person re- 
sponsible for the original description of a 
mutant was consulted concerning the ac- 
curacy of the description included in the 
volume, and was asked to contribute new 
data. In this part of the work, fifty-eight 
investigators were generous contributors 
and consultants. Many of the illustrations 
used in the volume are the work of Miss 
Edith M. Wallace; some of her drawings 
are here published for the first time, and 
some are republished. Other illustrations 
are reprinted from the publications of 
many workers, and have been redrawn by 
Miss Alice Hellmer or photographed by 
Miss Ruby Gay Stewartson. The finished 
manuscript was critically read as a whole 
by Drs. M. Demerec, T. H. Morgan, J. 
Schultz, C. Stern, and A. H. Sturtevant, 
and in part by several other authorities; 
and their suggestions have, so far as pos- 
sible, been faithfully carried out. 

Ultraviolet absorption in the salivary- 
gland chromosomes of mottled phenotypes. 
The work on ultraviolet absorption (see 
Year Book No. 40) has been continued by 
Dr. P. A. Cole and Dr. Sutton at the 
National Institute of Health, Bethesda, 
Maryland. One of the aims of this work 



192 



CARNEGIE INSTITUTION OF WASHINGTON 



was to investigate a possible correlation 
between phenotypic variegation, due to 
translocation of genes to heterochromatin, 
and the variation in absorption of ultra- 
violet by the bands with which these genes 
are associated. Larvae of two genotypes 
were used, one of which {w mot 258-21/ 
y sc w; Cy/ + ) shows rather slight varie- 
gation of the adult eye at 18 C, asso- 
ciated with an X-4 translocation. The 
other type (w mot 258-21/y sc w; Msio/ + ) 
has the same translocation together with 
a second-chromosome modifier which in- 
creases the phenotypic variegation so that 
the eye is largely white, with a few small 
flecks of red facets. A set of ultraviolet 
photomicrographs was made from larvae 
of each type. If there is a close correla- 
tion between the nucleic acid content of the 
bands and the degree of phenotypic varie- 
gation, a comparison of absorption by the 
normal and translocated bands in each set 
of photographs should show a significant 
difference between the two sets. 

Analysis of the data is now in progress. 
Inspection of the plates by eye does not 
reveal any marked difference between the 
two sets. Measurements of the plates have 
been made by means of a recording micro- 
photometer in the laboratory of Dr. I. 
Gersh, Department of Anatomy, Johns 
Hopkins Medical School, Baltimore, and 
the calculation of extinction coefficients 
from these measurements is now in prog- 



ress. 



Experiments with heavy water {deu- 
terium oxide). Dr. Stephen Zamenhof and 
Dr. Demerec conducted a series of ex- 
periments in which one generation of 
Drosophila was raised on food containing 
either 40 per cent or 55 per cent of heavy 
water. The males thus obtained were 
tested for X-chromosome lethals by the 
standard C1B method. It is known that if 
water containing deuterium reaches an 



organic compound, hydrogens that are con- 
nected with N and O exchange with the 
deuterium almost instantly, in a ratio cor- 
responding to the deuterium/hydrogen 
ratio in the surrounding water. This ex- 
change is easily reversible, and if pure 
water subsequently reaches this compound 
all the deuterium is replaced again by hy- 
drogen. Thus, in the present experiment 
it is estimated that the genes contained 
up to 30 per cent of C-connected deuterium 
and up to 40 per cent of N- and O-con- 
nected deuterium in place of hydrogen. 
Tests made on about 2000 treated sperms 
showed no increase in the frequency of 
lethals in treated flies as compared with 
controls. There are at least two possible 
explanations of these results. One is that 
the substitution of deuterium for hydrogen 
did not change either the structure or the 
activity of the gene; another possibility is 
that the gene structure did change, but 
was able to return to its original form as 
soon as deuterium was replaced by hy- 
drogen. 

Chromosome Breakage and 
Recombination 

Chromosomal rearrangements in Dro- 
sophila may be induced by X-ray treat- 
ment of spermatozoa of the adult male. 
As was reported in Year Book No. 39, 
evidence has been collected which indi- 
cates that although the potential breaks 
are induced in the mature sperm, new 
combinations of chromosomes do not arise 
until after the sperm nucleus has pene- 
trated the egg. Since the interval between 
irradiation of the sperms and their utiliza- 
tion in fertilization can be extended over 
many days without the occurrence of break 
recombination or restitution, an oppor- 
tunity is offered to attempt to alter these 
phenomena experimentally. Ability to al- 
ter the customary behavior of the X-ray- 



DEPARTMENT OF GENETICS 



193 



sensitized regions might throw some light 
on the nature of the disturbances produced 
in the chromosomes by irradiation. 

Presumably the chromosomes, following 
X radiation, are in a highly "labile" state, 
and in this condition may be sensitive 
to types of treatment that leave no im- 
print on the genetic constitution of the 
normal cell. Supplementary energy neces- 
sary to affect the regions of potential 
breakage might conceivably be supplied 
either by chemical or by physical agents. 
Use of the former seems less desirable be- 
cause of the difficulty of securing pene- 
tration into the nucleus without impairing 
or destroying the vital functions of the 
cell. An approach offering more promise 
of success is the use of radiant energy. 

In line with these considerations, a series 
of experiments have been designed by Drs. 
Kaufmann and Hollaender to measure 
the effects of several wave lengths in the 
near infrared and ultraviolet portions of 
the spectrum. So far as is known from a 
series of control experiments, neither of 
these agents is in itself instrumental in 
causing gross chromosomal derangements. 
The near infrared rays can be produced 
quite readily in high intensities, they are 
absorbed only slightly by water, and they 
penetrate well into living tissues. Rays 
in the range between 8000 and 15,000 A, 
obtained from a high-intensity source, have 
been concentrated on the Drosophila males, 
which were retained in a glass vial sur- 
rounded by a cooling coil. Results of 
these first experiments indicate that with 
increasing exposure to the infrared there 
is a decrease in the frequency both of 
altered sperms and of chromosomal breaks, 
as measured by cytological analysis of the 
Fi salivary glands of larval descendants 
of irradiated fathers. Thus, in one set of 
experiments in which 2000 roentgens of 
X rays were given, followed by infrared 
16 



and then another 2000 r, these values were 
obtained: 

Hours % altered -, . , 

■ c , % breaks 

inrrared sperms 

72 26.7 66.4 

144 20.9 58.9 

2l6 14. 1 32.I 

Control values for 4000 r (given in either 
single or fraction treatments) are about 
30 per cent altered sperms and 86 per 
cent breaks. 

Within the ultraviolet portion of the 
spectrum, the wave length 2537 A has been 
tested. Radiation of this type is most fully 
absorbed by the nucleic acid component 
of the chromosomes. Males exposed to a 
combined treatment of 4000 r plus the 
ultraviolet also gave much lower values 
than the X-ray controls, namely, 14.5 per 
cent altered sperms and 36.3 per cent 
breaks. 

Since these are only preliminary experi- 
ments, full appraisal of the physical and 
biological factors involved must await the 
compilation of additional data, including 
a more complete set of controls. One pos- 
sible explanation of the results is that the 
supplementary radiation serves to acceler- 
ate the process of repair or restitution that 
occurs naturally in some of the potential 
breaks induced by X radiation. 

The frequency with which such natural 
restitution occurs has been given further 
consideration by Dr. Fano. In Year Books 
Nos. 39 and 40, attention was directed to 
some theoretical and experimental ap- 
proaches to the correlation of data on 
chromosomal changes, obtained by ob- 
servations of dominant lethals and other 
cytogenetic techniques. It had been found 
that most of the lethals produced by low 
dosages of X rays behave as if they were 
due to single-break processes. Certain dif- 
ficulties, which at that time seemed to 
prevent full acceptance of this hypothesis, 



i 9 4 



CARNEGIE INSTITUTION OF WASHINGTON 



have now been removed by the work of 
G. Pontecorvo, of the University of Edin- 
burgh. We may thus accept the conclusion 
based on our data that single breaks are 
produced in Drosophila sperms at a rate 
of about 15 per cent per 1000 r of X rays. 
It is, however, not immediately clear 
whether most of the cases with a single 
breakage result in dominant lethals, or 
whether many of the single breaks "heal," 
thus to become completely obliterated. 
Data collected by other authors on dif- 
ferent materials indicate that the second 
alternative obtains; and the following 
considerations applying to Drosophila 
point in the same direction. 

If no other breakages were available 
than those detected by dominant-lethal 
counts, and assuming that individual 
breakages occur independently of one an- 
other, the frequencies of the occurrence of 
different numbers of breaks in the same 
sperm should follow a Poisson distribution. 
Accordingly, the expected frequency of 
sperms with two breaks at 1000 r ought 
to be approximately /4(o.i5) 2 «=* 1%. This 
figure is far too low to account for the 
frequency (^3%) of viable two-break 
rearrangements, so that we may conclude 
that the average frequency of potential or 
actual breakages at 1000 r considerably ex- 
ceeds 15 per cent. 

The number of points of potential 
breakage induced within a single nucleus 
may also be much greater than had been 
anticipated on the basis of the complexity 
of previously observed rearrangements. 
In earlier experiments a 14-break case had 
been analyzed; in the course of the studies 
combining X rays with the near infrared, a 
rearrangement was found by Kaufmann 
which involved at least 32 points of break- 
age. The positions of 30 of these breaks 
have been determined; others restricted to 
the proximal heterochromatin remain of 
uncertain location. Distribution of identi- 



fiable breakage points among the chromo- 
somes is as follows: 6 in the X chromo- 
some, 3 in the left limb of the second 
chromosome (2L), 5 in 2R, 3 in 3L, 12 
in 3R, 1 in the fourth chromosome. Aside 
from its great complexity, this rearrange- 
ment is particularly interesting because of 
the accumulation of breaks in the right 
limb of the third chromosome. The proba- 
bility of such a distribution on a chance 
basis is very small (between 0.02 and 0.05 
on the basis of the x 2 test) . In the light of 
this finding, our other data on complex re- 
arrangements are being examined more 
fully in an effort to secure additional in- 
formation concerning the nature of the 
breakage-recombination phenomenon. 

Another pair of glands analyzed in these 
studies illustrates the ability of two sister 
strands obtained from an irradiated chro- 
mosome to recombine independently of 
each other. These glands consisted of a 
mosaic of tissue containing two types of 
nuclei. One showed a mutual exchange 
between the 2R, 3L, and 3R chromosome 
limbs to give the following sequence of 
parts: 

2L tip centromere 60D/79B tip 3L 

3R tip. ..98D/79B... .centromere.. .98D/60D... tip 2R 

The remaining nuclei revealed a recipro- 
cal translocation of the following type: 

2L tip centromere 60D/79B tip 3L 

2R tip..6oD/79B centromere tip 3R 

Although the two patterns of recombina- 
tion differ with respect to the participation 
of the right limb of the third chromo- 
some, the sequence of events responsible 
for this condition must remain, as in other 
similar cases, open to various interpreta- 
tions. If it is assumed that the chro- 
mosomes of the irradiated sperm are un- 
split and that all regions of potential break- 
age are duplicated in the derived sister 
chromatids, we must further postulate that 



DEPARTMENT OF GENETICS 



195 



restitution has occurred in one of the 3R 
strands. On the other hand, we cannot 
eliminate the possibility that the chromo- 
somes of the sperm are already split longi- 
tudinally and that sister strands may re- 
spond either identically or independently 
within the same nucleus. 

Neutron Experiments 

Two peculiar facts have been reported in 
the literature concerning the distribution 
of neutron-induced recessive sex-linked 
lethals in Drosophila. Nagai and Locher 
have reported a nonrandom distribution 
of lethals among the sperms of different 
males. Nishina and Moriwaki have re- 
ported nonrandom distribution among 
sperms belonging to the same male. An ex- 
periment made by Dr. Fano was designed 
to check these unexpected findings. This 
experiment offered also an opportunity 
to examine several aspects of the compara- 
tive effects of X rays and neutrons, i.e.: 
(a) how frequently lethals are connected 
with cytologically detectable minute de- 
ficiencies, (b) how frequently lethals are 
connected with cytologically detectable 
gross chromosomal aberrations, (c) the 
relative frequency of recessive and domi- 
nant lethals. 

Wild-type Drosophila males were treated 
with approximately 600 and 1200 units 
neutrons, measured with a standard 25-r 
Victoreen r-meter, and mated partly to 
C1B virgin females, partly to wild-type vir- 
gin females. The treatment was kindly 
supplied by the Columbia University cy- 
clotron group, under the direction of Dr. 
J. R. Dunning. Dominant-lethal counts 
were made on Fi offspring from wild- 
type females. Fi C1B females from C1B 
parent females were mated singly to their 
ec cf v g 2 brothers and tested for recessive 
lethals. The maleless F 2 cultures — that is, 
those carrying a lethal — were further tested 



by mating the wild-type females with 
ec cf v g 2 males. F3 cultures were raised 
for 62 lethals, to determine the location 
of the lethal and to obtain salivary-gland 
cytological preparations. 

The dominant-lethal counts have been 
completed, and show the following results, 
which are in fair agreement with those of 
Dempster : The fraction of adults hatching 
from eggs fertilized by treated sperm was 
90 per cent for the controls, 27 per cent 
for the 600-unit treatment, and 4 per cent 
for the 1200-unit treatment. According to 
results reported in Year Book No. 40, 
it takes respectively about 3000 and 6000 r 
of X rays to produce the same effect. As- 
suming that 1 unit neutrons is energetically 
equivalent to about 2.5 r X rays, it takes 
about twice as much X-ray energy as 
neutron energy to produce the same domi- 
nant-lethal effect. This factor of 2 is 
larger than that (1.5) found by Dempster, 
but the two results are not strictly com- 
parable because Dempster investigated the 
dosage necessary to induce 50 per cent 
lethality, instead of 73 per cent or 96 per 
cent as in the present experiments. 

The investigation of the recessive lethals 
is still in progress, and only tentative re- 
sults can be indicated. The distribution 
of lethals does not seem to depart from 
randomness — a result at variance with the 
results both of Nagai and Locher and of 
Nishina and Moriwaki. No lethal has 
yet been found cytologically to be con- 
nected with a deficiency. A large per- 
centage of the lethals (about one-third) 
seems to be connected with chromosomal 
rearrangements. This result deviates from 
the findings on X-ray-induced lethals, but 
is not unexpected, because the ratio of the 
frequency of gross chromosomal changes 
to that of gene mutations is generally 
higher in neutron-treated than in X-rayed 
material. The over-all frequency of re- 



196 



CARNEGIE INSTITUTION OF WASHINGTON 



cessive lethals per unit dose of energy 
absorbed from radiation has been found 
to be lower in neutron-treated than in X- 
rayed material, in agreement with the 
findings of Timofeef-Ressovsky and Zim- 
mer, already confirmed by Demerec, Kauf- 
mann, and Sutton. 

Since neutrons are less efficient than X 
rays in producing sex-linked recessive 
lethals in Drosophila, when equal amounts 
of radiation energy are absorbed, Dr. Fano 
was interested in investigating the theo- 
retical information that can be derived 
from this comparison. A detailed theory 
of this phenomenon was developed by Lea, 
which led to the evaluation of certain im- 
portant quantities relating to gene struc- 
ture. Since, however, this theory involved 
certain very special assumptions, an ef- 
fort was directed toward estimating its ac- 
tual significance. 

If the production of ionizations along 
the paths of particles traversing tissue were 
extremely dense, it is conceivable that all 
particles passing close enough to the point 
where a mutation might occur would ac- 
tually produce it. Under these conditions, 
the experimental rate of production of 
mutations would yield a measurement of 
the cross section of the "sensitive region" 
which represents the "target" to be "hit" 
by the particles. This sensitive region may 
have some significant connection with ge- 
netic structures; and therefore the evalua- 
tion of its cross section represents a desir- 
able goal. As a matter of fact, no available 
radiation produces such a high density of 
ionizations as to fulfill the conditions de- 
scribed above. The theory developed by 
Lea, however, permits an extrapolation 
from the data available on the action of 
neutrons to the ideal case of infinitely 
dense ionization. 

It has been found that this theory is sub- 
ject to the following criticism: The hy- 
potheses underlying it were selected as 



the simplest schema fitting the present 
knowledge; the factors necessarily neg- 
lected might have been expected to aver- 
age out, so that the results would be ap- 
proximately correct. On the contrary, it 
turns out that all the neglected factors act 
in the same direction, so that the corre- 
sponding deviations from Lea's theoreti- 
cal law add up instead of canceling 
out. Consequently, Lea's estimate of the 
cross section of the sensitive region, which 
is based on an extrapolation, is certainly 
in error by defect, by an undetermined 
amount which may conceivably be very 
large. 

Radiation Experiments in Neurospora 

It has been found by Hollaender and 
Emmons, working with Fungi Imperfecti, 
that fungi afford suitable material for 
studying the effect of ultraviolet radiation 
in producing mutations. The changes 
produced in Fungi Imperfecti could not 
be subjected to genetical test, however, 
and it was thought advisable to extend 
the study to a fungus in which the 
changes could be tested by being passed 
through a sexual stage. The ascomycete 
Neurospora crassa was finally chosen as 
the best available plant for this purpose, for 
several reasons. The life history of this 
fungus has been studied in detail by 
Dodge, who found it to be heterothallic 
and its sexual reproduction to be sub- 
ject to experimental control. Lindegren 
and others have investigated its inherit- 
ance and found that Mendelian segre- 
gation occurs in the young ascus. More- 
over, Neurospora crassa produces under 
certain reproducible conditions a special 
type of spores, "microconidia" or "sper- 
matia." These spores, by virtue of their 
small size, uniformity, and probable uni- 
nucleate condition, afford favorable ma- 
terial for radiation experiments, as has 
been demonstrated by Lindegren. 



DEPARTMENT OF GENETICS 



197 



This is a cooperative experiment with 
the National Institute of Health, in which 
Dr. M. Demerec, Dr. A. Hollaender, Mrs. 
M. Houlahan, and Mrs. Eva Sansome are 
taking part. The ultraviolet experiments 
are being performed by Hollaender and 
Houlahan at Bethesda, Maryland, and the 
X-ray experiments at Cold Spring Harbor; 
but every effort is being made to keep the 
conditions of the experiments as nearly 
comparable as possible. 

Microconidia are obtained from the mu- 
tant strain fluffy, which does not form 
macroconidia. Fluffy cultures that are not 
more than three weeks removed from a 
single-spore (ascospore or microconidium) 
stage are used, in order to lessen the 
chance of irradiating spores from a cul- 
ture that has become heterokaryotic by 
spontaneous mutation. The spores are ex- 
tracted in salt solution, filtered through 
cotton under sterile conditions, centrifuged, 
and treated in suspension in salt solution. 
For the X-ray experiment a concentrated 
suspension of spores in a small vial hold- 
ing about 1 cc. of suspension is irradiated. 
Samples of 0.1 cc. are taken for the con- 
trol and for the different dosages given. 
Increase in dosage is obtained by increas- 
ing the time of exposure. In order to keep 
the selection of mutants as constant as 
possible, only the more distinct types are 
scored as mutants. 

As a control on the ultraviolet experi- 
ments, 577 untreated spores were isolated, 
of which 1 was a mutant. In the X-ray 
experiment, 1 mutant was obtained from 
521 untreated spore cultures. The spon- 
taneous mutation rate, therefore, is low, 
and so far has been of a similar intensity in 
the Bethesda and Cold Spring Harbor 
cultures. 

In the ultraviolet experiments the wave 
lengths tested, arranged in order of ef- 
fectiveness in producing mutation, are 
2650, 2537, 2480, 2805, 2380, 2967, 2280 A. 



An average of 4.7 per cent of mutations 
has been recorded for treatments at 2650, 
the highest recorded rate being 13 per cent. 
Nucleic acid has maximum absorption in 
this region of the spectrum. 

In the X-ray experiments a wave length 
of about 0.3 A was used and dosages of 
2250, 4500, 9000, 13,500, 18,000, and 22,500 r 
units have been given. The preliminary 
results indicate a linear increase in muta- 
tion rate up to the highest dosage given, 
as shown below: 

_ % mutations 

Dosage 

among survivors 

2,250 1 

4>5 00 3 

9> 000 5-5 

i3>5 00 9- 8 

18,000 10 

22,500. . . .' 14 

There seems to be some evidence that 
the X-ray treatment at these dosages stimu- 
lates the germination of the microconidia. 
This makes it difficult to detect killing ef- 
fects of low magnitude. It is reasonably 
certain, however, that up to 22,500 r units 
the survival ratio of treated to control 
spores is more than one-half. It is pro- 
posed therefore to increase the dosage un- 
til an appreciable amount of killing is ob- 
tained. 

Of the 119 ultraviolet mutants so far 
obtained, 11 are "dwarfs," 18 "unstable," 
40 "semilethals," and 50 unclassified; of 99 
X-ray-induced mutants, 11 are "dwarfs," 
14 "unstable," and 3 "semilethal." Of 
about 40 ultraviolet-induced mutations sub- 
jected to preliminary genetical analysis, 
1 is possibly a two-gene change, and the 
others behave as single-gene mutations. 
Of 23 X-ray-induced mutations, 12 may be 
single-gene mutants, whereas 11 are defi- 
nitely not single-gene mutants. Of these 
11, 7 show the type of ascospore sterility 
associated with chromosomal alteration. In 



i 9 8 



CARNEGIE INSTITUTION OF WASHINGTON 



addition, 10 other X-ray-induced muta- 
tions gave empty perithecia when crossed 
with normal. 

In the case of the ultraviolet experiments, 
in which wave lengths with an appreciable 
effect in inducing mutations are used, the 
mutation rate increases with increased en- 
ergy up to a certain point, and then de- 
creases. The X-ray results show a steady 
increase in mutation rate with dosage, up 
to the highest dosage given. It is neces- 
sary to increase the X-ray dosage until 
an appreciable amount of killing is ob- 
tained, in order to see whether this will 
be accompanied by a fall in the mutation 
rate or whether the fall in mutation rate 
is peculiar to the ultraviolet treatment. 
The high rate of occurrence of semilethals 
in the ultraviolet experiments, as con- 
trasted with the X-ray experiments, raises 
the question whether they are to be cor- 
related with the high death rate in the 
ultraviolet experiments or whether they 
are a special effect of the ultraviolet treat- 
ment. This question also may be answered 
by increasing the X-ray dosage. 

The suggestion that single-gene mutants 
are more frequent in the ultraviolet ex- 
periments, where they may be almost the 
only type of mutant, is in accord with ex- 
pectation. 

The unstable or reverting types of mu- 
tant raise special problems. Reversion prob- 
ably results from the overgrowth of "nor- 
mal" nuclei in a heterokaryon consisting of 
normal and mutant nuclei. The hetero- 
karyotic condition of the mycelium may be 
brought about in several ways. It may 
result from a mixing of nuclei, because a 
"mutated" and a normal spore are picked 
up together; or one spore may give rise 
to two types of nuclei, because only one 
chromatid of a divided chromosome is 
affected. Another possibility is that re- 
verse mutation occurs either at the same 



or at a different locus. However the het- 
erokaryotic condition is brought about, 
it results in a unique situation in which 
natural selection may occur within an 
organism. 

Giant Chromosomes in Mosquitoes 

Dr. Sutton has studied giant chromo- 
somes in two species of mosquito, Culex 
pipiens and A'edes aegypti, eggs of which 
were obtained by courtesy of Dr. J. Maier, 
of the Rockefeller Institute, New York. 

The giant chromosomes are found in 
the salivary glands, mid-gut, and Mal- 
pighian tubes of the larvae, and persist to 
the adult stage in the Malpighian tubes. 
Fairly satisfactory preparations were ob- 
tained by using the Malpighian tubes of 
fourth-instar larvae, pupae, or newly 
emerged adults, which had been kept at 
10-18 C. for a few days, pretreating with 
acetic-alcohol for 1 minute, and staining 
with acetic orcein (1 per cent orcein in 
45 per cent acetic acid) for about 1 hour. 

The giant chromosomes have the charac- 
teristic banded structure of the salivary- 
gland-type chromosomes studied in other 
Diptera. Both the species studied have a 
haploid chromosome number of 3. In 
Culex pipiens the individual chromosomes 
can be followed along their whole length, 
but in A'edes aegypti their continuity is 
confused by numerous contact points be- 
tween different chromosome arms and a 
tendency for the chromosomes to break at 
these points. 

This investigation gives some reason to 
believe that a comparison of giant-chromo- 
some maps might be useful as a means of 
distinguishing between different species 
and subspecies of mosquitoes. Some obser- 
vations on the development and a brief 
description of the characteristic features 
of the giant chromosomes in the two spe- 
cies have been published elsewhere. 



DEPARTMENT OF GENETICS 



199 



The Theory of Conjugated Double 
Bonds 

The fundamental properties of a large 
number of compounds important in or- 
ganic and biologic chemistry are known 
to be determined by the presence of chains 
of conjugated double bonds. The nature 
of the phenomenon of conjugation has 
been understood theoretically for a num- 
ber of years, but attempts to develop a 
detailed theory of the systems of conju- 
gated bonds have not yet progressed very 
far. A part-time project was undertaken 
by Dr. Fano, directed toward an under- 
standing of the correlation between the 
absorption spectrum — that is, the "effec- 
tive color" — and the length of an aliphatic 
chain of conjugated bonds. It was found, 
in the first place, that no essential dis- 
crepancy exists between the present experi- 



mental and theoretical knowledge on this 
subject. Further knowledge was gathered 
on other theoretical questions, among 
which are the following: (a) the effect 
of electronic exchange on the absorption 
spectrum, especially for very long chains; 

(b) the difference in properties between 
chains involving different terminal groups; 

(c) the correlation between the absorption 
spectrum and the shape of the chain (this 
correlation allows us to reach certain con- 
clusions on the shape of the chain, a sub- 
ject about which very little is known yet, 
either theoretically or experimentally) ; (d) 
an approach to the theoretical determina- 
tion of the most stable shape of the chain. 
This project was, however, discontinued 
because it was expanding beyond expecta- 
tion under circumstances which seemed 
to be unsuitable to its further development. 



MOUSE GENETICS 

E. C. MacDowell, J. S. Potter, V. Bryson, M. J. Taylor, 
E. N. Ward, and T. Laanes 



Spontaneous Leukemia: Foster-Nursing 
Experiment 

In certain mice the incidence of spon- 
taneous leukemia can be modified by a 
maternal influence transmitted in the proc- 
ess of nursing and differing according to 
the strain of the nurse (Year Book No. 40) . 
The surprising thing about this result is 
that the degree of the influence is not 
necessarily correlated with the frequency 
of leukemia in the nurse's strain. That 
nurses from two low-leukemia strains 
might differ in their influence was not even 
conceived when the above experiment was 
planned, and nurses from the two strains 
were used for purely practical reasons. 

Although attention has been directed 
primarily to the role of genetic consti- 
tution, this result carries such interesting 
implications that its full confirmation and 



interpretation appear to be an obligation. 
After long deliberation on the minimum 
requirements for critical evidence, an ex- 
periment to test this nursing influence di- 
rectly has been undertaken; and, with the 
weaning of all the experimental animals, 
the initial phase has been completed. The 
establishment of this long-time experiment 
is reported in some detail in the interest 
of cooperation and of avoiding wasteful 
duplication. 

Each litter from reciprocal matings be- 
tween strains C58 and StoLi was dis- 
tributed at birth as evenly as possible to 
foster nurses from each of the three strains 
C58, StoLi, and Bagg albino (Balb), mak- 
ing six experimental classes. The first 
milk of the nurses had been taken by 
other young, but the first milk obtained 
by the experimental animals came from 



200 



CARNEGIE INSTITUTION OF WASHINGTON 



their foster nurses. To obtain 416 entirely 
unnursed young and raise 403 of them 
successfully with a variety of foster nurses 
is, in itself, an accomplishment. In order to 
maintain conditions as normal as possible, 
all treatment of mothers' nipples and all 
mechanical devices were avoided; each 
young was removed from the nest by hand 
soon after its birth, and held in cotton wool 
until the last of the litter was born and 
the foster nurses were ready. To do this, 
four observers shared a continuous night- 
and-day watch of the females approaching 
term and recorded a series of direct obser- 
vations on parturition behavior and birth 
times of individual mice. This appears to 
be the first time that any comparable series 
of observations has been made on the 
mouse. Many questions are raised, and a 
new approach to an understanding of the 
processes of parturition is suggested. 

A contrast appeared in the parturition 
behavior of the mothers from the two 
strains. Those from strain C58 concen- 
trated their attention on the job and car- 
ried it through with directness and as- 
surance. The fetal membranes were usu- 
ally broken by the mother in assisting the 
delivery; after a young was well cleaned, 
the placenta, which often did not appear 
till later, would be rapidly and completely 
eaten. StoLi mothers were generally 
highly nervous; their attention wandered 
and the various operations were performed 
vaguely, in fits and starts. The young 
might not be completely cleaned and the 
placenta was seldom more than nibbled 
about the edges. The young and placenta 
frequently appeared together, with all 
membranes intact; the placenta might be 
somewhat eaten, but the young left un- 
recognized within the membranes. In 
such cases, however, the observer would 
remove the membranes and save the young. 
The rapidity of asphyxiation in unbroken 
membranes suggests that the dehiscence 



of each placenta must precede the delivery 
of each young by a very short time, and 
that the separation of the placenta is the 
immediate determinant of an individual 
birth; it follows that the order of dehis- 
cence is regularly from behind, forward. 
The birth of an entire litter commonly 
requires a whole hour and occasionally 
much longer. 

A further strain difference appeared in 
the distribution of births with relation 
to the time of day. The 28 litters from 
StoLi mothers were scattered fairly evenly 
throughout the twenty-four hours, with a 
slight accumulation at 4 a.m. accounting 
for 4 more births between midnight and 
noon than between noon and midnight. 
Of the 29 litters from C58 mothers, 28 were 
born in daylight. Starting with one at 
4 a.m., the frequencies tended to increase 
till 5 p.m.; none was born between 6 p.m. 
and 4 a.m. 

At 28 days each hybrid mouse was 
weaned, marked, weighed, and assigned 
to a permanent box together with a mouse 
from each of the other five experimental 
classes, as far as this was possible with 
sexes separate. The proportion of males 
from C58 mothers was less than from 
StoLi mothers (42 per cent and 54 per 
cent). The weaning weights provide a 
measure of the relative success of the differ- 
ent strains of nurses, since the distribution 
of newborn animals was purely random 
and since each nurse in a set of three al- 
ways raised the same number of young 
(5 in almost all cases) . Inequalities within 
sets of three were removed by adding new- 
born Bagg albinos where necessary. 

The frequency distributions of weights 
of the 28-day young show unquestionable 
differences according to the strain of the 
nurse. The modes for the three distribu- 
tions lie in ascending i-gram classes in the 
order C58, StoLi, Balb; but the means 
for C58 and StoLi nurses are about 0.5 g. 



DEPARTMENT OF GENETICS 



201 



apart, whereas the means for StoLi and 
Balb nurses are 2 g. apart. How long these 
effects of the different kinds of nurses on 
weight will persist, and whether they have 
any connection with the nursing influence 
on leukemia, will appear later. 

Screw-Tail Mutation 

Continued study of mice showing the 
screw-tail mutation, first reported last year, 
has added numerous effects to the already 
extensive list and correspondingly enlarged 
the range of problems presented. The new 
problems bear particularly on the deter- 
mination of skeletal pattern. Each ter- 
minal effect offers a clue to the develop- 
mental mechanics of a given part. After 
these specific mechanisms are recognized, 
determination of the interrelation of their 
antecedent stages becomes the goal. That 
they all depend upon one gene indicates 
some ultimate interrelation. Whether one 
gene may have more than one action is 
frequently discussed. It would seem more 
helpful to ask, At what stage and why 
do the chains of events leading from 
one gene to the diverse terminal effects 
become separated? In such a search the 
basic problem of differentiation in devel- 
opment becomes identified with the prob- 
lem of gene action. 

Many mutations, when not lethal in 
early stages, confuse the processes of de- 
velopment so violently that they contribute 
little toward the analysis of normal de- 
velopmental processes. The outstanding 
importance of the screw-tail mutation is 
due to the moderation of its effects, which 
therefore become relatable to normal. 

The original evidence that this muta- 
tion is due to one gene has been amply 
confirmed by more than doubling the 
number of mice from segregating pairs 
(total, 2998 mice) ; by raising the num- 
ber of tested normal sibs of screw-tails to 



76 (51 heterozygous, 25 homozygous) ; and 
by the reappearance of the mutation, in- 
tact, from outcrosses into two different 
strains (one of these crosses was made 
by Dr. L. C. Dunn at Columbia Univer- 
sity). A deficiency of screw-tails, originally 
reported for males only, now appears to 
be evenly divided between males and fe- 
males. This is ascribed to prenatal loss, 
which becomes selective for screw-tails 
only in the presence of unfavorable con- 
ditions as indicated by increased prenatal 
mortality of normals. As reported at one 
time from this laboratory, prenatal mor- 
tality of normal mice is lowest in first 
litters and increases with successive litters. 
In first litters the expected proportion of 
screw-tails is found; in later litters the 
total number decreases and the proportion 
of screw-tails is reduced until it finally 
approaches zero. Thus the numerical de- 
ficiency of screw-tails shown by the totals 
depends on the number of litters included 
from each mother and has little signifi- 
cance. This result does not indicate 
whether the increasingly unfavorable con- 
ditions are due to the number of preced- 
ing pregnancies or to the age of the mother, 
but it does establish a type of variable 
selective elimination that may very pos- 
sibly help to explain other cases. 

The following newly discovered effects 
have been studied in an extensive series 
of alizarin-stained skeletons ranging from 
2 days before birth to more than a year 
afterward: 

1. The pelvis is shifted about one verte- 
bra nearer the tail, separating the ilium 
from the initially first sacral vertebra, 
which develops as a lumbar vertebra, free 
from the remaining three sacral vertebrae. 
The consistency of this effect will permit 
an embryological study that will bear di- 
rectly on the interpretation of the varia- 
tions often found in the number of hu- 
man lumbar vertebrae. 



202 



CARNEGIE INSTITUTION OF WASHINGTON 



2. The centra of scattered thoracic and 
lumbar vertebrae are malformed. They 
arise from paired, instead of single, bone 
centers, and as maturity approaches cause 
sharp spinal flexures, bending outward. 

3. The lower jaw is grossly malformed. 
Even before birth the pattern of the jaw 
shows a deviation from normal. The dis- 
tortion becomes progressively more ex- 
treme through a large part of life, in con- 
nection with the abnormal growth of the 
teeth. 

4. The lower incisor teeth do not grow 
back into the ramus of the jaw; both upper 
and lower incisors show defective enamel 
formation and curve in too sharply. These 
conditions lead to abnormal wearing of 
the cutting ends in all cases, and frequently 
to extreme malocclusion. In old age, for- 
ward growth of the incisor through the 
jaw may become blocked so that the basal 
end is forced backward through the solid 
bone, sometimes penetrating its surface. 
The specific relation between various 
physiological states and variations in the 
structure of rat incisors demonstrated by 
Schour gives the histological study of these 
teeth great importance. 

5. Roots of molar teeth are always feebly 
developed, and there is only one socket 
for each tooth instead of a separate socket 
for each of the three roots. Some of the 
molars are frequently absent or mis-ori- 
ented. The failure of root development, 
even when a single molar lying on its side 
is the sole occupant of the tooth cup, in- 
dicates a defect within the tooth rather 
than an abnormality in the growth of the 
surrounding bone. 

6. The top of the skull shows the sagittal 
sinus permanently uncovered by bone and 
the coronal suture arching sharply back- 
ward with numerous small sutural bones. 
The modification of these membrane 
bones, as well as of the jaw, shows that the 
action of the gene is not limited to carti- 



lage bone, or rather cartilage, for no evi- 
dence has appeared to indicate that the 
actual process of ossification is in any way 
abnormal. 

7. From the first deposition of bone the 
sternum is always a single, unsegmented 
bone, shorter and broader than normal; 
the first and fourth to seventh ribs are al- 
ways attached, but the ends of the second 
ribs are frequently free, as are the ends of 
the third ribs occasionally. 

Since more questions have been raised 
than answered by the study of the above 
effects, further comment will be reserved 
on all but the sternum, which warrants a 
fuller account. 

The absence of all traces of segmenta- 
tion not only makes the screw-tail sternum 
an unparalleled mammalian structure, but 
also provides a clue to the cause of the 
normal pattern. Hanson has interpreted 
the presence of sternebrae "as arising from 
a process of segmentation in response to 
the demand for as great a measure of 
elasticity on the ventral side of the animal 
as is allowed by the more or less flexible 
vertebral column of the dorsal side. Su- 
tures arising in this manner, as a result 
of strain, will naturally appear at the 
weakest parts along the sternum. At the 
points of attachment of the ribs the 
sternum is often deeply notched, weaken- 
ing this region, and here, as expected, oc- 
cur the lines of division of the sternum 
into segments or sternebrae." The follow- 
ing provides an interpretation more closely 
related to the actual developmental proc- 
esses: 

In the embryonic sternum of the mouse 
a persisting growth center is established 
at the end of each rib. Although the rib 
end is histologically homogeneous, a grad- 
ual differentiation from the most immature 
to fully differentiated cartilage cells can 
be followed, passing from the rib end in 
any direction into the sternum. In screw- 



DEPARTMENT OF GENETICS 



203 



tails, the opposite rib ends are so far apart 
that the zones of immature cells on the 
right do not meet those on the left and the 
oldest cartilage forms a continuous band 
along the mid-line. Since bone can be de- 
posited only after cartilage is fully mature, 
the first bone in a screw-tail sternum there- 
fore forms a continuous longitudinal 
streak. In normal mice, the opposite rib 
ends are so close together that the zones 
of immature cells on the right lie in con- 
tact with those on the left, breaking up 
the mature cartilage cells into a series of 
separate masses. Thus the bone centers 
form a series of intercostal bands at right 
angles to the main axis. The fusion of the 
right and left growth zones leads to the 
formation of pairs of transverse epiphyseal 
growth centers, which account for the 
elongation of the bone centers, with slight 
increase in width. In screw-tails, on the 
other hand, the opposite growth zones can- 
not unite. Each remains practically in con- 
tact with the neighboring zones on the 
same side, so that at birth the sides of the 
sternum are bordered by cartilage, whose 
continued growth primarily increases 
sternal width. 

The dependence of growth centers in 
the sternum upon the rib ends is admirably 
demonstrated by the variable failure of 
second and third screw-tail ribs to be- 
come attached. Without exception, there 



is never a growth center when the rib 
fails to reach the sternum, and there is 
always one when the rib is attached. 
Wherever there is no growth center, ossi- 
fication quickly extends to the margin of 
the sternum, which is always narrower 
at these points. 

A further confirmation of this interpreta- 
tion has been found in numerous non- 
screw mice, in which the distance of the 
rib ends from the mid-line is normal but 
the two members of a pair are not oppo- 
site. This may involve a single pair of 
ribs or several, and the dislocation may be 
slight or very marked. Correspondingly, 
either the growth zones meet at an angle, 
or they do not meet at all and each re- 
mains an independent lateral center exactly 
as in screw-tails. In every case the bone 
pattern follows the distribution of fully 
matured cartilage, from sternebrae with 
crooked ends, to half-size sternebrae stag- 
gered in position on the two sides, and, 
finally, to a continuous wall of troy pattern 
with segmentation eliminated. 

The longitudinal shift in the positions 
of rib ends leading to a staggered sternum, 
and the transverse shift leading to the 
broad screw-tail sternum, are clearly due 
to very different causes; but the materials 
of the sternum in the two cases appear to 
be intrinsically alike, and equally under 
the control of the ribs. 



ENDOCRINE STUDIES 

O. Riddle, W. F. Hollander, R. A. Miller, E. L. Lahr, G. C. Smith, 
and H. N. Marvin 



The endocrine organs perform a singu- 
lar type of "team work" concerned with 
physical and mental development, and at 
all life stages they share largely in the 
regulation of reproduction, growth, bodily 
maintenance, and behavior. Discovery of 
the extent to which certain hormones of 
the pituitary gland share in this "team 



work" continues as a central aim in most 
of the studies described here. 

Hormonal Basis of Maternal Behavior 
in Rats 

The results of nearly six years of study 
of this subject by Riddle, Lahr, and Bates 
have now been analyzed and published. 



204 



CARNEGIE INSTITUTION OF WASHINGTON 



More than 2900 tests were made with 
19 different hormones or hormonal prepa- 
rations, to determine the role of hormones 
in the exhibition of unlearned maternal 
behavior in rats. The more important 
facts relating to this prolonged study of an 
"instinct" are summarized here. 

Intact albino rats, aged 60 to 70 days, 
were tested especially for retrieving (that 
is, carrying young rats, mice, or squabs 
to a nest) and cuddling responses daily for 
10 days. By this means about 22 per cent 
of "normal reactors" were separated from 
the nonreactor rats. Thereafter these non- 
reactors were subjected to hormonal injec- 
tion for 10 days, with daily records of be- 
havior extending over a further 10-day 
period. All hormones were tested on a few 
or many males and females and on cas- 
trates of both sexes. 

In responding female rats whose mam- 
illaries had been developed with estrone 
during 20 days, the validity of the criteria 
of response (that is, retrieving and cud- 
dling) was attested by the ability of these 
rats actually to feed and rear the adopted 
young. 

The maternal drive or instinct was initi- 
ated in large or in significant numbers of 
normal and castrate male and female rats 
during injection (or pellet implantation) 
with various hormones: prolactin, proges- 
terone, desoxycorticosterone, intermedin, 
luteinizing hormone, phenol, and thyrox- 
ine; testosterone failed only in normal 
males. The instinct was not activated by 
injection with follicle-stimulating hormone, 
"growth" hormone, adrenotrophin, Prolan, 
pregnant mare serum, parathyroid extract, 
or a special extract of thyroid tissue. 

Most, but possibly not all, of the effec- 
tive substances rather clearly exerted an 
anti-gonad action on the intact rats; the 
term anti-gonad seems inapplicable to 
luteinizing hormone, although it too had 
a tendency to arrest estrous cycles. Castra- 



tion alone slightly increased the propor- 
tion of "normal reactors," and also in- 
creased the effectiveness of all substances 
capable of exciting the maternal response. 

Intact males were as likely as intact fe- 
males to be "normal reactors," but non- 
reacting (control) males were more re- 
sistant than (the slightly smaller) females 
to the maternalizing action of all the ef- 
fective hormones. 

Pregnant mare serum, gonadotrophin 
plus thyrotrophin, and estrone all had 
much or appreciable ability to terminate 
well established maternal behavior. These 
substances do not exert this action in rats 
deprived of their hypophyses, but they are 
effective in thyroidless rats. 

Removal of the pituitary gland precipi- 
tates maternal behavior in approximately 
50 per cent of otherwise intact female 
rats, but not if a decrease of the ovarian 
function is prevented by injections of 
pregnant mare serum. Nonreactors fol- 
lowing hypophysectomy can, in most cases, 
be made maternal with either prolactin 
or progesterone. 

In male rats, thyroidectomy alone ex- 
cites maternal behavior in about 25 per 
cent of such tests. Male rats not made 
maternal by this operation seem thereafter 
more resistant than normal rats to the 
positive action of prolactin, progesterone, 
and luteinizing hormone. 

The degree of purity or of contamination 
of the various pituitary preparations used 
was ascertained. Progressively larger doses 
of prolactin — 6, 18, and 30 units — progres- 
sively increased the percentage of rats of all 
sex types made maternal by treatment. 

Recurrent maternal behavior in repro- 
ducing rats (the rats tested were not in 
reproduction) probably does not depend 
on the several hormones here found to 
be directly or very indirectly active, but 
on that one of the group which (a) is re- 
leased in increased amount at the right 



DEPARTMENT OF GENETICS 



205 



time, (b) exerts an anti-gonad action, and 
(c) then directly or indirectly increases 
the excitability of the sensorimotor mecha- 
nism specifically involved in this instinctive 
behavior. Though present information is 
inadequate, the hormone that apparently 
best fits these requirements is prolactin. 

Genetic relationships and differences be- 
tween mating drive and maternal drive 
become clearer in the light of results ob- 
tained in the present study and in our pre- 
vious study on broodiness in fowl. The 
mating drive, or perhaps merely an un- 
expressed basis for that drive, is appar- 
ently a necessary precursor of the maternal 
drive. It thus appears that the maternal 
drive or instinct is remotely conditioned 
by the pituitary hormones (gonadotroph- 
ins) which govern the building of egg, 
sperm, and sex accessories, and is prob- 
ably precipitated and regulated by another 
pituitary hormone (prolactin) which is 
related broadly to the feeding and care 
of young. 

Pituitary Hormone Action in Carbo- 
hydrate and Fat Metabolism 

Last year's report noted that those ex- 
tracts from anterior pituitary tissue which 
have marked "diabetogenic" actions are 
mixtures of hormones. The extent to 
which posterior-lobe hormones (and inter- 
medin) contribute to the effectiveness of 
those mixtures was then almost wholly 
unknown. This topic has been investi- 
gated during the present year by Riddle 
and Marvin, but the results can be de- 
scribed more conveniently in connection 
with a summary statement on the entire 
subject which is planned for next year. 

A valuable aid to study of the hormones 
contained in effective extracts was ren- 
dered by Drs. E. M. K. Geiling and G. 
Chen, of the Department of Pharmacology, 
University of Chicago. Utilizing their 



newly developed methods for the assay 
of intermedin (melanophore hormone), 
they have examined our standard-type pi- 
tuitary preparations and determined that 
their content of melanophore units is as 
follows: whole anterior pituitary extract 
(no. 650), 1760 units; gonadotrophin plus 
thyrotrophin (no. 630), 2000 units; pro- 
lactin (no. 657), 94 units; prolactin (no. 
861), 100 units; a "mother" fraction (no. 
804) from which ammonium sulfate frac- 
tionation is done (see last year's report), 
340 units; whole posterior pituitary (alka- 
line) extract (no. 779), 2940 units; whole 
extract of beef muscle (no. 681m), units. 
This information makes it possible to esti- 
mate or to exclude the effects of intermedin 
on the sugar, glycogen, fat, and ketone 
values obtained following the use of our 
standard preparations. 

Gross differences in response of the liver 
to first and later daily dosage with insulin 
and prolactin. Studies on this topic were 
largely completed by Riddle and Opdyke 
prior to the present year, but the results 
were reported only in part last year. Pi- 
geons survive huge doses of insulin, and it 
is known that a course of 4 to 7 daily 
injections of prolactin doubles the weight 
of their livers. Young pigeons were given 
from 1 to 5 daily injections of insulin or 
prolactin, and differences between the re- 
sponse to a first and to subsequent injec- 
tions were measured in the case of liver 
glycogen and fat, ketonemia and glycemia. 
All values were obtained at the end of a 
24-hour fast. A first treatment with insulin 
(70 units per kilo of body weight) was 
found to increase liver fat by about 160 
per cent, but under further dosage the fat 
falls to or below the normal values. First, 
but not later, insulin injections produce 
ketonemia (at 10 hours after injection). 
Twelve hours after a first injection the 
blood sugar is decreased by 25 per cent, 



2o6 



CARNEGIE INSTITUTION OF WASHINGTON 



but 12 hours after a second daily injection 
it is increased by 50 per cent in both nor- 
mal and hypophysectomized birds. Twen- 
ty-four hours after a first injection of pro- 
lactin the percentage of liver glycogen is 
increased, but third and later injections 
neither maintain nor produce this increase; 
in these tests, and during at least 6 days, 
total liver fat is increased essentially paral- 
lel with increase of hepatic tissue. 

Though the nutritive state of these ani- 
mals is affected by temporary and pro- 
longed dosage with either insulin or pro- 
lactin, these results mainly reflect the abil- 
ity of the first dose of these hormones to 
set a new level of functioning in one or 
another regulatory organ (adrenal, pan- 
creas, pituitary). These studies, therefore, 
contribute to an understanding of the 
normal mechanism concerned in the regu- 
lation of carbohydrate and fat metabolism. 

Effects of anterior pituitary preparations 
and insulin on islet cells of the pigeon pan- 
creas. There is uncertainty concerning the 
number and the cellular sources of hor- 
mones secreted by the pancreas, and also 
uncertainty concerning functional inter- 
relations between pituitary and pancreatic 
hormones. Other current studies, particu- 
larly those on carbohydrate and fat metabo- 
lism, have supplied an abundance of var- 
iously treated pancreatic tissues which are 
suitable for a clarification of some of the 
above-mentioned problems. This material 
has been utilized during the past two years 
by Dr. Miller, with the results stated below. 

Three types of islet cell are identifiable 
in the pigeon pancreas. In young Carneau 
pigeons fasted 10 days, and in pigeons 
whose pituitary glands have been removed, 
the beta cells seem inactive or degenerat- 
ing; only slight changes in alpha and delta 
cells occur. Force-feeding of hypophysec- 
tomized pigeons maintains a normal ap- 
pearance in the three types of cell. Pro. 
lactin, overfeeding, partial pancreatectomy, 



and some preparations of corticotrophin all 
stimulate beta cells; gonadotrophin and 
thyrotrophin have no effect. Large doses 
of insulin induce a marked atrophy of 
beta cells. 

Four series of pituitary extracts obtained 
by fractional precipitation with ammonium 
sulfate (whose effects on glycemia, keto- 
nemia, and liver fat were fully described 
in last year's report) were tested in nor- 
mal and hypophysectomized pigeons and 
found to induce degenerative changes in 
beta cells. Stimulation of delta cells was 
observed with certain fractions from 10 
hours after a single injection to 24 hours 
after the last of 7 daily injections. Sub- 
stances stimulating delta cells are most 
concentrated in material precipitated at 
one-third saturation (fractions B and C) 
and tend to be insoluble on dialysis. There 
is an association between the delta-cell- 
stimulating action of these fractions and 
their ability to increase liver fat. Limited 
delta-cell stimulation occurs in pigeons 
treated with prolactin and with insulin. 
The actions of ammonium sulfate fractions 
on delta cells are not directly associated 
with any particular one of the hormones 
known to be present in these impure 
preparations. 

The granules of alpha cells are markedly 
depleted by insulin and less markedly by 
some ammonium sulfate fractions and by 
corticotrophins. 

The cytology of the pigeon adrenal cor- 
tex in experimentally induced atrophy and 
hyperactivity. The activity of the adrenal 
cortex is at least partly controlled by the 
pituitary gland, and one or more hor- 
mones produced by the cortex are known 
to play a part in carbohydrate metabolism. 
These facts led Miller and Riddle to a 
careful study of the cellular changes that 
accompany hormone production in cells 
of the adrenal cortex. The appearance of 
the Golgi apparatus, mitochondria, lipoid, 



DEPARTMENT OF GENETICS 



207 



cholesterol, and water-insoluble ketones in 
adrenal cortical cells of young (1.9 to 2.4 
months old) normal Carneau pigeons was 
compared with the cytological picture in 
experimentally induced atrophy and hyper- 
activity. The conclusions now drawn from 
this study complete and notably supple- 
ment the related studies described in earlier 
reports. 

Mitochondria seem to be involved in 
the formation of cortical hormone (s) 
which, together with a possible precursor 
(cholesterol), is present in the lipoid drop- 
lets. The rate of formation of lipoid nor- 
mally exceeds the demands of the organ- 
ism, and storage results. The Golgi appa- 
ratus may transform lipoid into the final 
product. In stimulated adrenals a marked 
proliferation of mitochondria maintains 
the rapid formation and excretion of lip- 
oid; cholesterol, lipoid, and water-insoluble 
ketones are diminished. Following hy- 
pophysectomy cortical activity is limited to 
a few peripheral cells, and in a few adre- 
nals these peripheral cells give little or no 
indication of activity. Injections of cortical 
hormone into unoperated pigeons cause 
atrophy of the cortex; similar injections 
into hypophysectomized pigeons further 
decrease the weight of the gland and sup- 
press the activity of cells in the peripheral 
zone. In hypophysectomized pigeons, for- 
maldehyde and several nonpituitary hor- 
mones produce cytological changes in the 
cortex which are similar to those resulting 
from corticotrophin. Adrenal cells of nor- 
mal nestlings and adult pigeons show 
greater activity than do those of young 
preadolescent pigeons. 

Alleged thymus mediation of pituitary 
function. A series of papers published in 
1940 by Bomskov and co-workers in Frei- 
burg reported the preparation and the 
extensive investigation of an ether-soluble 
extract of the thymus. Such an extract was 
said to be "diabetogenic" in rats, guinea 



pigs, and pigeons, in that it showed 
marked glycogenolytic and hyperglyce- 
mic actions. Those investigators further 
claimed that a diabetogenic-thymotrophic 
fraction obtained by them from the pitui- 
tary gland is identical with "growth" hor- 
mone, and that physiologic effects of the 
latter pituitary substance are thus also me- 
diated by the thymus hormone. The 
strong claims of these workers to a resolu- 
tion of problems in which this laboratory 
has long been interested led Wells, Riddle, 
and Marvin to repeat the Freiburg studies. 
With none of three preparations of an 
ether-soluble extract of calf thymus was it 
possible to confirm the reports of the Frei- 
burg group. Neither glycogenolytic, gly- 
cemic, nor ketogenic activity was observed 
in rather extensive tests on rats and pi- 
geons. No significant leucocytosis was ob- 
tained in rats. Short-term tests showed no 
appreciable effects on bodily growth in 
young rats, chicks, or pigeons. 

A technique for thyroidectomy in the 
pigeon and the early effect of thyroid re- 
moval on heat production. Investigations 
frequently require the use of birds com- 
pletely deprived of their thyroid tissue, and 
the technique hitherto employed in this 
operation on pigeons was in some respects 
unsatisfactory. Marvin and Smith have 
developed a technique for a two-stage oper- 
ation that avoids the immobilization of the 
crop ("crop binding") which is frequent 
when other methods are used. Elimina- 
tion of this effect increases the usefulness 
of the operated birds for the various stud- 
ies on metabolism that require thyroidless 
birds. The effect of the operation on the 
respiratory metabolism is almost immedi- 
ate. The basal heat production of 8 birds 
was apparently somewhat depressed at 4 
to 5 days after the removal of one thy- 
roid, and in 13 birds the basal metabolism 
was —20 at 7 to 8 days after complete 
thyroidectomy; in another group of 7 pi- 



208 



CARNEGIE INSTITUTION OF WASHINGTON 



geons a value of — 27 was obtained at 6 to 
46 days after complete thyroidectomy. Al- 
most all birds survive this operation, and 
the technique permits a rapid and usually 
a complete removal of the thyroids of 
pigeons. 

Adrenal Cortical Hormone and 
Prolactin 

The relation of hormones of the adrenal 
cortex to growth. During the past few 
years this laboratory has directed some ef- 
fort to an analysis of the means by which 
the anterior pituitary gland promotes and 
regulates growth. In tests made with 
mammals, other laboratories have essen- 
tially failed to find that adrenal cortical 
hormones — all probably produced under 
stimulation by pituitary corticotrophin — 
support or increase body weight in hy- 
pophysectomized animals. Using pituitary- 
less pigeons, Miller and Riddle have ob- 
tained positive results with cortical extract, 
and particularly with desoxycorticosterone 
acetate; moreover, this effect on body 
weight has been shown to be additive to 
the support afforded by minute doses of 
prolactin. The present experiments repre- 
sent short-term tests, and they are more 
directly concerned with prevention of the 
large loss of body weight that follows re- 
moval of the pituitary, but their bearing 
on the problem of growth is evident. Parts 
of the data are shown in figure 2. 

After removal of the anterior pituitary 
gland from groups of Carneau pigeons 
aged 7 weeks, the birds were injected 
daily for a period of 10 days, then sacri- 
ficed, and the weights of various organs 
obtained. Operated birds given no treat- 
ment during this 10-day period show an 
average loss of 21 per cent of their body 
weight. Groups of operated pigeons in- 
jected with an extract of adrenal cortex 
lost 13 and 14 per cent of their original 



weight. When these birds were injected 
with desoxycorticosterone acetate at opti- 
mal dosage, 2 to 3 mg. daily, this loss of 
weight was reduced to 6 per cent; doses 
larger than 3 mg. were toxic. When this 
substance and testosterone propionate were 
injected together, the male sex hormone 
showed no ability to assist growth or to 
maintain body weight. Groups injected 
daily with 1 mg. desoxycorticosterone lost 
10 per cent, and those injected daily with 
1 unit of prolactin lost 8 per cent, of their 
preoperative weight. When these quanti- 
ties of the two hormones were injected to- 
gether, the birds regained all the weight 
lost as an early or incidental result of the 
operation (see fig. 2) and at killing were 
1 per cent heavier than at the start of the 
test. Preliminary tests, which are subject 
to further confirmation, have suggested 
that the injection of only 0.005 m §- °f tn Y" 
roxine in addition to 1 mg. of desoxycorti- 
costerone and 1 unit of prolactin increases 
this gain in body weight to 4 per cent. 
This gain equals the average gain shown 
by animals that retain their pituitaries and 
are subjected to no operation during this 
same 10-day period. These hormones, and 
mixtures of hormones, also maintained or 
increased the weights of the intestine and 
liver, but they had no similar action on 
thyroids, testes, and adrenals. 

The hormones that replace the effect of 
the pituitary in the maintenance or increase 
of body weight stimulate appetite and 
food consumption notably, and they ap- 
parently enable pigeons to utilize their 
food more efficiently. Extract of adrenal 
cortex and desoxycorticosterone also mark- 
edly increase the intake and output of 
water. Determinations of the water con- 
tent of breast muscles and livers of treated 
and control birds show that the support of 
body weight by these hormones is not ac- 
complished by, and is not a consequence 
of, the hydration of these tissues. 



DEPARTMENT OF GENETICS 



209 



Smaller numbers of tests of the action 
of cortical hormone and prolactin in adre- 
nalectomized pigeons support the conclu- 
sion already presented. Uninjected adre- 
nalectomized pigeons lost 12 per cent of 
their preoperative weight in 10 days. Daily 
dosage with 50 units of prolactin caused a 



105 — 



Local crop-sac or micro method for as- 
say of prolactin. Two years ago it was 
noted that several nonpituitary substances, 
when injected intracutaneously over the 
crop, stimulate cell division in the lining 
of the pigeon's crop sac. Those observa- 
tions indicated that certain precautions 



oesoxycort. Img 

PROLACTIN I unit 

thyroxine 0.005mg 

desoxycort. Img 
prolactin I unit 



PROLACTIN I unit 




Fig. 2. Graph showing support of body weight in groups of pigeons (10 to 38) by daily injec- 
tions of desoxycorticosterone acetate with and without the addition of 1 unit of prolactin. The 
data are for the 10-day period immediately following the removal of the anterior pituitary gland 
of Carneau pigeons aged 7 weeks. 



significant temporary increase in weight, 
but at the end of 10 days the animals 
(some near death from lack of life-main- 
taining cortical hormone) had lost about 
8 per cent of their preoperative weight. 
Birds of one group injected daily with ex- 
tract of adrenal cortex together with 50 
units of prolactin increased their body 
weight by 9 per cent in 5 days. 



must be taken in the use of this method 
for the micro-assay of prolactin. At that 
time, however, it was not possible to ac- 
count for the disturbing fact that two 
seemingly valid criteria of crop-sac stimu- 
lation were in frequent disagreement. 
Thus, at 24 or 48 hours after an injection 
many of the crop sacs examined by trans- 
mitted light seemed thickened and rugose 



17 



210 



CARNEGIE INSTITUTION OF WASHINGTON 



(positive response), though actual counts 
of dividing cells (after colchicine) showed 
no increase in the rate of cell division. 
During the present year Lahr and Riddle 
have clarified this difficulty by showing 
that visible thickening and rugosity may 
result (and persist for 48 hours) from in- 
creased cell divisions strictly limited to 
short periods (2 to 7 hours) following 
the injection. An entirely normal rate of 
cell division in an epithelium that was defi- 
nitely thickened as a result of an earlier 
treatment involves, therefore, no real con- 
tradiction. It was shown, further, that 
leukotaxine (1.0 mg.) is one of the sub- 
stances that temporarily (4 and 7 hours) 
stimulate mitoses and also tend to show 
visible stimulation (positive response) at 
24 or 48 hours after the last previous in- 
jection. This demonstration that a "wound 
substance" shares in this response, and that 
its action is immediate and of short dura- 
tion, has special significance; it supports 
the view that the entire list of nonspecific 
substances may exert their action on the 
crop epithelium as a secondary result of 
their excitation of "wound substance" in 
or near the lining of the crop. In con- 
trast, prolactin is effective when injected 
at sites far removed from the crop sac; its 
specific ability to cause proliferation of 
crop epithelium wholly independent of 
"wound substance" therefore seems un- 
questionable. 

Breeding Operations and Study of En- 
demic Goiter in Pigeons 

In February 1942, Dr. Hollander be- 
came associated with this group, more espe- 
cially to assist in the genetic analysis of 
breeding operations conducted by Riddle 
on doves and pigeons during more than 
twenty years, and in the preparation of this 
material for publication. In addition, cer- 
tain genetic and physiological tests on some 



segments of this large bird colony are 
continuing with his aid or supervision. 

Adequate analysis now clearly shows 
that the "scraggly" pigeon character, which 
has been extant in the colony since its 
inception, is a simple recessive trait. The 
ratios obtained in summaries of the four 
possible types of mating show a moderate 
deficiency in the scraggly classes, but this 
is interpreted as evidence of a higher mor- 
tality of scragglies than of normals during 
the early period (to 10 to 14 days after 
hatching) when scragglies cannot easily 
be distinguished from normals. Plumage 
and skin defects, and an abnormally high 
rate of heat production, definitely distin- 
guish the scragglies from normal birds. 

Outcrosses of females of our hermaphro- 
dite-producing strain of pigeons to males 
of normal stocks have produced a high 
percentage of sons having rudimentary left 
oviducts, but no ovotestes have appeared. 
On the other hand, hermaphroditic or par- 
tially hermaphroditic males (those merely 
with left oviducts) outcrossed to females 
of normal stocks have given thus far only 
normal offspring. 

The apparent relation of endemic goiter 
in pigeons to embryonic weakness has led 
to an investigation of this subject. Thy- 
roid enlargement, up to 250 times normal 
size, has been observed occasionally in our 
pigeons over a period of many years. The 
study is still in progress, but it is clear 
that the goitrous tendency is most marked 
in old birds and among pigeons of the 
large breeds; it is rare in the ringdoves. 
It has been established that occurrence of 
enlarged thyroids in reproducing female 
pigeons is highly correlated with poor 
hatchability, late hatching, and the produc- 
tion of weak offspring. Reference to the 
fact that eggs from goitrous female pigeons 
require 2 to 3 extra days of incubation 
was contained in the report for 1929-1930 



DEPARTMENT OF GENETICS 



211 



(Year Book No. 29). It is now found that 
the offspring of goitrous mothers also usu- 
ally have large thyroids at hatching. 

Preliminary tests for effects of supple- 
ments of potassium iodide in the mother's 
diet indicate that her enlarged thyroids 
regress toward normal size within a few 
weeks, and that there is coincident im- 
provement in the hatchability of her eggs 
and the vigor of her offspring. The effect 
of this treatment on the heat production 



of these adult birds is not yet adequately 
determined, but Smith has shown that 
short-term administration of larger doses 
of the iodide to groups of young pigeons 
increases their rate of heat production by 
5 to 19 per cent. Extremely goitrous pi- 
geons have shown clear evidence of defi- 
ciency of thyroid hormone; their ability 
to regenerate feathers spontaneously from 
plucked areas is greatly decreased and their 
basal heat production is diminished. 



ANTHROPOLOGY AND HUMAN GENETICS 

Morris Steggerda and Catherine Shaffer 



Anthropometry 

Child development. It is known that 
some human populations are taller and 
heavier today than they were in years 
past. For example, students from some col- 
leges are taller and weigh more on the 
average than did their parents when they 
attended school. United States soldiers 
are said to be heavier now than were the 
soldiers in the First World War, and they, 
in turn, were heavier than those of the 
Civil War. This tendency has been re- 
ported from various parts of the world and 
is often accounted for by better living 
conditions. Meredith, reporting on data 
from Iowa school children, showed that 
mean statures and weights for children 
in 1930-1937 were respectively % inch and 
3 pounds greater than those from the 
preceding decade. Similarly, data from the 
schools of Hagerstown, Maryland showed 
an increase in weight for children meas- 
ured in 1940 as compared with those 
measured in 1933. 

When the present study on the growth 
of children of different races began, in 
1931, it concerned the growth of individu- 
als and did not deal with mass statistics. 
In 1941, however, in view of the previ- 
ously mentioned trends in growth, a large 



number of Dutch white and Navajo 
children were measured for stature and 
weight. These data were averaged for 
each age, sex, and race. By combining all 
the Dutch white children measured in 
1931 to 1934 and the Navajo children meas- 
ured in 1932 to 1934, a sufficient number 
was obtained for comparison with the 
1941 groups. The results obtained are 
summarized briefly in table 1 and in fig- 
ure 3. 

It will be noticed from table 1 that, for 
every age, the 1941 children are taller than 
those of 1931-1934. Most often the differ- 
ences are not statistically significant. The 
trend, however, is definite. The differ- 
ences in the 11- and 16-year groups are 
more than three times the probable error 
of the difference, and may be considered 
statistically significant. A weighted aver- 
age of the differences shows that the 
children of 1941 are 13.63 mm. taller than 
those of the 1931-1934 group. For weight 
the same condition exists in that, for every 
age, the 1941 children are heavier. The 
weighted average of differences here is 
exactly 5 pounds. In nine of the twelve 
age-group categories the differences are 
significant, being more than three times 
the probable error. 



212 



CARNEGIE INSTITUTION OF WASHINGTON 



The data for the Dutch white females 
are practically identical, showing the 
weighted average of stature to be 12.54 
mm. greater for each age in 1941 than in 



the results for the males are similar. It 
will be noticed that the height of the 1941 
Navajo children is greater for each age 
than that of the 1932-1934 children. Simi- 



TABLE 1 

Means and probable errors for height and weight of Dutch white male children measured 
in Holland, Michigan, 1931 to 1934, as compared with others measured in 1941 





1931-1934 


1941 


Age 


No. 


Stature (mm.) 


Weight (lbs.) 


No. 


Stature (mm.) Weight (lbs.) 


6.. 

7.. 

8.. 

9.. 
10.. 
11.. 
12.. 
13.. 
14.. 
15.. 
16.. 
17.. 


100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
68 
37 


1151.40±3.11 
1218.20±3.21 

1267.40±3.82 
1324.20±3.87 
1375.00±4.37 
1412.00±3.80 
1481.20=1=4.52 
1528.00±4.86 
1601.40±5.70 
1665.00=1=6.05 
1690.88±7.10 
1733.78±6.68 


44.80±0.35 

50.25±0.43 

55.00±0.42 

62.50±0.54 

67.10±0.70 

73.05±0.71 

84.60=1=1.19 

88.40±0.97 

103.10±1.22 

111.85=1=1.43 

122.50=1=1.69 

130. 34=1= 1.70 


88 

94 

95 

99 

107 

105 

104 

110 

57 

79 

97 

90 


1162.96±3.65 
1229.58±3.79 
1274.64±3.78 
1335.46±3.84 
1385. 14=1=3.61 
1431.90±3.95 
1483.26±4.67 
1534.36±4.75 
1619.48±7.97 
1677. 34=1= 7. 00 
1731.86±5.47 
1754.22=1=5.08 


45.91=1=0.43 

52. 87=1=0. 63 

57.56±0.55 

63. 92=1=0. 57 

70.35=1=0. 77 

76.88±0.81 

86.16±1.01 

94. 23=1=1. 09 

111. 63=1=1. 75 

122.63=1=1.63 

136. 16=1=1. 49 

139. 11=1=1. 52 




AGE IN YEARS 



WEIGHT OF NAVAJO FEMALES 
1932-34 and 1941 



x x= 1932-34 

O 0=1941 




Weighted average of 
differences^ 4,01 lbs. 



J I I I I I l l i l 



J L 



> 10 II 12 13 14 IS 16 17 16 
AGE IN YEARS 



Fig. 3. Height and weight of Navajo female children measured in New Mexico and Arizona 
in 1932 to 1934, as compared with others measured in 1941. 



1933, and that of body weight 4.57 pounds 
greater. 

For the Navajo children, the data are 
shown in the form of graphs (fig. 3). For 
these we show only the females, although 



larly, the graphs for weight indicate heav- 
ier children in 1941 than in 1932-1934. 
The weighted averages of differences for 
stature indicate an increase of 15.29 mm. 
and, for weight, 4.01 pounds. Figures for 



DEPARTMENT OF GENETICS 



213 



male Navajos were 12.07 mm. and 4.67 
pounds, respectively. 

The unique feature of these data is that 
the children were all measured by one 
person using a similar technique. It can- 
not be said that Dr. Steggerda's technique 
varied in this decade, for properly balanced 
scales were used and the same deductions 
were made for the minimum clothes worn 
during the measuring. As for the tech- 
nique for taking stature, he vouches for 
the similarity of his technique for these 
two periods. 

Believing that still more data would 
prove helpful, Dr. Steggerda obtained from 
the Department of Physical Education at 
Tuskegee Institute, Alabama, the heights 
and weights of Negro women taken by the 
teachers during the past decade. The data 
for 1934 were compared with those for 
1 941, and the results obtained indicated the 
same trend as that found for the Dutch 
and Navajos. The Negro data are not ar- 
ranged according to age, since the age 
limits were approximately the same (17 
to 23), but rather one mean was made for 
stature and another for weight for the two 
periods. The results are summarized as 
follows: Stature, 1934, 1609.20 ± 2.53 mm.; 
1941, 1625.38 ± 2.24 mm. Weight, 1934, 
118.47 ± 0.73 pounds; 1941, 121.99 — °-^9 
pounds. 

No positive data are available to explain 
these increases in height and weight dur- 
ing this very short period of time. We are 
aware of the general increase in height 
and weight of many human populations. 
We know that the depression did affect 
the food intake of the Dutch whites in 
Holland, Michigan. We know, also, that 
the Navajo Indians enjoy better living con- 
ditions and more healthful surroundings 
now than they did 10 years ago. We know, 
further, that the entire population con- 
sumes more vitamins and is more con- 
scious of them today than 10 years ago. 



But which factors determine the increase 
has not been ascertained. The present pur- 
pose is merely to add these data to the 
literature with the hope of a future 
explanation. 

Comparative measurements of Negro 
and white men. In 1938 the physical pro- 
portions of 100 Negro women from 
Tuskegee Institute, Alabama were de- 
scribed and compared with a series of 
white girls from Smith College who were 
also measured by Dr. Steggerda. During 
the present year a similar set of data in- 
volving 100 Negro men from Tuskegee 
Institute has been analyzed and compared 
with data on white college men supplied 
by Professor H. H. Plough from Amherst 
College. 

The average stature of the Tuskegee 
men was 1749 mm., or 30 mm. greater than 
that of the large Negro army series of 
Davenport and Love, and 44 mm. greater 
than that of a group of unselected Negro 
males supplied by Herskovits. The Tuske- 
gee Negroes were 26 mm. or approxi- 
mately 1 inch shorter than Amherst Col- 
lege men, although their weight was the 
same, namely 70.06 kg. In sitting height 
the Tuskegee students averaged 33 mm. 
less than the Amherst students, a fact 
which indicates the relatively short trunks 
and long legs of the Negro boys. This is 
shown also in the relative sitting height, 
which for Negroes is 50.9 per cent as com- 
pared with 52.1 per cent for Amherst 
whites; the average trunk height of the 
white students, therefore, is relatively 
greater than that of Tuskegee Negro 
students. This finding is not at all new, 
but is included as an additional record. 

In biacromial breadth, i.e., width of 
shoulders, the Tuskegee Negroes averaged 
410 mm., or more than the Amherst stu- 
dents, who averaged 402.5 mm. 

In span or length of the outstretched 
arms, the Tuskegee men averaged 1847 



214 



CARNEGIE INSTITUTION OF WASHINGTON 



mm., or over 2 inches more than the Am- 
herst men. This difference in arm span 
is more apparent when relative span is 
considered, namely, arm stretch divided 
by stature. This for the Tuskegee Negroes 
averaged 106.2 per cent and for the Am- 
herst students 101.2 per cent, a difference 
which is highly significant. 

In this study of Negro males, 60 direct 
and derived measurements were con- 
sidered. 

Anthropometric technique. It has long 
been recognized that the technique of an- 
thropometry varies greatly among anthro- 
pometrists. A problem was devised where- 
by a number of anthropometrists were to 
measure the same subject in order to de- 
termine the extent of the variations for 
different dimensions. It was planned also 
to supply the anthropometrist with only 
one direction, namely, to measure the 
subject with the technique familiar to him, 
selecting the dimensions that he deemed 
important. In this way the relative impor- 
tance of each dimension as considered by 
the leading anthropometrists could be as- 
certained. The subject and Dr. Steggerda 
visited the laboratories of the twenty-one 
anthropometrists who participated in this 
experiment. 

The average number of measurements 
taken by the twenty-one investigators was 
24. One took as few as 16, and another 
took as many as 45 dimensions. Only 18 
were taken by more than one-half of the 
twenty-one investigators. 

These 18 measurements showed both 
uniformity and differences in technique, 
as was evidenced by the variability of the 
distributions. Stature, sitting height, head 
length, head breadth, and nose breadth 
showed sufficient uniformity to warrant 
the conclusion that no great differences in 
technique were involved. 

The rest of the 18 measurements, how- 
ever, were obviously taken with dissimilar 



techniques. Intercristal breadth varied 
from 272 mm. to 324 mm., a difference of 
more than 2 inches. Nearly the same 
difference was found for biacromial 
breadth. The measurements for hand 
length varied as much as 20 mm., and 
measurements of the face also showed 
wide variations. Especially in the measure- 
ments involving the location of the nasion 
were the results too variable for accuracy. 

A number of other inconsistencies of 
technique became apparent. For example, 
in locating the landmarks on the shoul- 
ders and hips there was no uniformity of 
pressure exerted and no apparent agree- 
ment as to whether the points of measure- 
ment should be the bony landmarks or the 
outside contours. Also, there was little 
uniformity in the instruments used for 
body measurements. All agreed, for ex- 
ample, that head height was an important 
measurement, yet four different instru- 
ments were used by the eleven investiga- 
tors who took this measurement. 

The experiment definitely showed a 
need for clearer directions for taking shoul- 
der width, chest transverse, chest A.P. 
(anteroposterior), intercristal breadth, nose 
length, hand length, and hand breadth. 

It was recommended to the Society of 
Physical Anthropologists that a committee 
be appointed to make the necessary recom- 
mendations for the development of uni- 
formity in the study of anthropometry. 

Cross Sections of Human Head Hair 

In Year Book No. 39, a unique method 
was described for cross-sectioning a large 
number of human head hairs at one opera- 
tion. In last year's report a summary was 
given showing the effects of race, sex, age, 
and the region on the shaft where the 
section was made, upon the size and shape 
of the hair. During the year more work 
was done relative to the change in size and 
shape of head hair with age. 



DEPARTMENT OF GENETICS 



215 



Fifty Maya Indian females and 53 males, 
ranging from the age of 1 to 69, were se- 
lected. Approximately 75 hairs from each 
individual were sectioned and measured. 
The hair was cut close to the scalp in the 
same region of the head, and the sections 
were all made 20 mm. from the original 
cut. Both the males and the females were 
put into 10-year age groups, and the means 
and standard deviations with their prob- 
able errors were calculated for the area and 
for the index. The results are given in 
table 2. 



males in three age groups, and greater 
in four. 

Work on the hair sections is being con- 
tinued, with special reference to the man- 
ner of hair growth in and from the fol- 
licles. Histological sections have been 
made from both Negro and white scalps. 
Cross sections of hairs in the dermis seem 
to indicate the same racial characteristics 
that they demonstrate in hair outside the 
scalp. Correlations are being made of such 
cross sections. Information is also being 
gathered on the shape of the hair follicles, 



TABLE 2 

Means and probable errors for area and index of cross sections of Maya head hair from 

individuals of various age groups 



Age group 


Area (a 2 / 100) 


Index 


Males 


Females 


Males 


Females 


0-9 
10-19 
20-29 
30-39 
40^9 
50-59 
60-69 


27.09±0.35 
37.82±0.32 
40.62±0.47 
39.67±0.35 
33. 17±0. 42 
39.75±0.44 
32.46±1.13 


27.48±0.82 
33. 57±0. 27 
40.57±0.58 
35.15±0.31 
35.98±0.36 
32.32±0.38 
29.63±0.37 


88.49±0.22 
83.61±0.23 
83.47±0.37 
80.61±0.30 
80.62±0.31 
81.50±0.35 
80.06±0.67 


88. 93±0. 33 
82.63±0.23 
80.94±0.44 
84.29±0.25 
77.71±0.35 
83.82±0.34 
85.46±0.38 



From this table it is apparent that Maya 
hair is smallest in early childhood and in- 
creases rapidly in both males and females 
to a maximum in the 20-29 a § e § rou P- 
Thereafter the area tapers off, except for 
an extraordinary rise in the male 50-59 
age group. In the majority of age groups, 
the females had smaller hair. On the 
other hand, the index drops considerably, 
indicating a more elliptical cross section 
in progressing from the average age of 5 
to that of 15. In the males this diminution 
continues to the average age of 35 and 
then remains fairly constant thereafter. 
The female trend is rather irregular, with 
peaks in the groups 30-39, 50-59, and 
60-69; trie m dex is less than that of the 



with the aim of correlating this with the 
final hair shape. 

Teeth 

Differences and similarities in the teeth 
of four racial groups have been reported 
in previous Year Books. Differences have 
been demonstrated in the amount of caries 
present and also in the eruption time of 
teeth. The races were similar in the order 
in which teeth appeared in the mouth. 
At present an attempt is being made to 
correlate dental development with the 
growth of the individual. The prelimi- 
nary findings indicate a very low correla- 
tion, almost negligible, which means that 
although tooth eruption correlates with 



2l6 



CARNEGIE INSTITUTION OF WASHINGTON 



chronological age, it does not necessarily 
correlate with general body development. 
Thus, because an individual grows fast in 
body size it does not mean that his dental 
development will necessarily be earlier. 
For this problem, means have been estab- 
lished for various body proportions for 
each age and sex, as well as the mean 
eruption time for each tooth for each age 
and sex, and the above-mentioned corre- 



lations are now being made. 



South American Indians 

In 1932 Dr. Steggerda made a survey of 
statures and cephalic indices of the vari- 
ous Indian tribes of North America. Two 
years ago a survey was begun, at the re- 
quest of the Smithsonian Institution, to 
determine the known anthropometry of 
South American Indians; and, at present, 
this study has progressed to include some 
anthropometrical data on more than 80 
different tribes. For some tribes several 
investigators have contributed data, so that 
the study includes 132 different investiga- 
tions on the 80 tribes considered. The 
general observations deduced from this 
survey reveal that: 

The South American Indians are, on the 
average, shorter in stature than the North 
American Indians. Fifteen tribes of those 
studied show a stature below 155 cm. The 
greatest number of tribes (43) is found 
in the stature group 1 60-1 64.9 cm. There 



were 2 tribes in the group representing 
statures of from 180 to 184.9 cm -> namely 
the Onas and Tehuelches, both located in 
the southernmost part of the South Ameri- 
can continent. 

The range in stature is greater in the 
South American Indians than in those of 
North America. In other words, the short- 
est and the tallest American Indians are 
to be found in South America. Among 
the tribes belonging to the shortest stature 
group we find individuals averaging as low 
as 145 cm.; on the other hand, the high- 
stature group includes mean body heights 
of 184 cm. 

Regarding the cephalic index, only 2 
tribes show an index under 76 per cent, 
namely the Chipaya and Alacaluf, the low- 
est cephalic index having been found in a 
group of Chipaya males that showed an 
average of 72.8 per cent. Percentages of 
84 and over were found to exist in 13 dif- 
ferent tribes, with the Conibos showing the 
highest index, 91.36. Other body dimen- 
sions are being listed for further study, 
and contour maps are being made to show 
the geographical location of the various 
Indians relative to their body proportions. 

The review also concerns the hybrid 
populations of South America. Much is 
being learned regarding cultural traits, 
food habits, growth, and development, all 
subjects which have been studied in de- 
tail by Dr. Steggerda for the Maya and 
Navajo Indians of North America. 



BIBLIOGRAPHY 



Avery, A. G., and A. F. Blakeslee. A white 
flowered race of Datura which is geneti- 
cally distinct from similar white races in 
nature. Proc. Nat. Acad. Sci., vol. 27, pp. 
512-518 (1941). 

Bates, R. W., T. Laanes, E. C. MacDowell, 
and O. Riddle. Growth in Silver dwarf 
mice, with and without injections of an- 
terior pituitary extracts. Endocrinology, 
vol. 31, pp. 53-58 (1942). 



— and O. Riddle. Annual variation in the 
response of crop-sacs and viscera of pigeons 
to prolactin. Endocrinology, vol. 29, pp. 
702-709 (1941). 

and E. L. Lahr. A strain differ- 
ence in responsiveness of chick thyroids to 
thyrotrophin and a step-wise increase dur- 
ing three years in thyroid weights of Car- 
neau pigeons. Endocrinology, vol. 29, pp. 
492-497 (1941). 



DEPARTMENT OF GENETICS 



217 



Bates, R. W. See Riddle, O. 
Bishop, M. See Demerec, M. 
Blakeslee, A. F. Origin and ideals of the Na- 
tional Science Fund. Science, vol. 94, pp. 

356-358 (i94i)- 

— Growth patterns in plants. Growth, suppl. 

5, pp. 77-88 (1941). 

Individuality and science. Science, vol. 

95, pp. 1-10 (i94 2 )- 

Induced evolution in plants through 

chromosome changes. (Abstract) Proc. 8th 
Amer. Scientific Cong., vol. 3, p. 173 (1942). 

See Avery, A. G.; Sansome, Eva R.; 



Satina, S.; van Overbeek, J. 

Brehme, K. S. Development of the Minute 
phenotype in Drosophila melanogaster. Jour. 
Exper. Zool., vol. 88, pp. 135-160 (1941). 

Cole, P. A., and E. Sutton. The absorption of 
ultraviolet radiation by bands of the sali- 
vary gland chromosomes of Drosophila 
melanogaster. Cold Spring Harbor Sym- 
posia on Quant. Biol., vol. 9, pp. 66-70 
(1941). 

Conklin, M. E. See van Overbeek, J. 

Demerec, M. Cold Spring Harbor Symposium 
on Genes and Chromosomes. Jour. Heredity, 
vol. 32, pp. 391-392 (1941). 

Unstable genes in Drosophila. Cold 

Spring Harbor Symposia on Quant. Biol., 
vol. 9, pp. 145-149 (i940- 

Chromosomal changes in Drosophila 

melanogaster and their evolutionary signifi- 
cance. Proc. 8th Amer. Scientific Cong., 
vol. 3, pp. 37-41 (1942). 

Alexander Hollaender, M. B. Houla- 

han, and M. Bishop. Effect of monochro- 
matic ultra-violet radiation on Drosophila 
melanogaster. (Abstract) Genetics, vol. 27, 
pp. 139-140 (1942). 

B. P. Kaufmann, and E. Sutton. Ge- 
netic effects produced by neutrons in Dro- 
sophila melanogaster. (Abstract) Genetics, 
vol. 27, p. 140 (1942). 

See Kaufmann, B. P. 



Dunham, H. H. See Riddle, O. 

Fano, U. An analysis of induced chromosomal 
changes in Drosophila. Cold Spring Harbor 
Symposia on Quant. Biol., vol. 9, pp. 113- 
120 (1941). 

An autosomal recessive factor inducing 

semi-sterility in Drosophila melanogaster 
females. Proc. Nat. Acad. Sci., vol. 28, pp. 
1 19-123 (1942). 



On the theory of the "color" of unsatu- 
rated aliphatic chains. (Abstract) Phys. Rev., 
vol. 61, p. 736 (1942). 

Hill, T. J. See Steggerda, M. 

Hollaender, Alexander. See Demerec, M. 

Houlahan, M. B. See Demerec, M. 

Kaufmann, B. P. Induced chromosomal breaks 
in Drosophila. Cold Spring Harbor Sym- 
posia on Quant. Biol., vol. 9, pp. 82-91 
(1941). 

Reversion from roughest to wild type in 

Drosophila melanogaster. Genetics, vol. 27, 

PP- 537-549 (1942)- 

and M. Demerec. Sperm utilization in 

Drosophila melanogaster following single 
and multiple inseminations. (Abstract) 
Genetics, vol. 27, p. 150 (1942). 

See Demerec, M. 



Laanes, T., and E. C. MacDowell. Screw-tail, 
a new mouse mutation. (Abstract) Genetics, 
vol. 27, pp. 151-152 (1942). 

See Bates, R. W. 

Lahr, E. L. See Bates, R. W.; Riddle, O. 
McClintock, B. The stability of broken ends 

of chromosomes in Zea mays. Genetics, vol. 

26, pp. 234-282 (1941). 

The association of mutants with homozy- 
gous deficiencies in Zea mays. Genetics, vol. 
26, pp. 542-571 (i94i)- 

Spontaneous alterations in chromosome 



size and form in Zea mays. Cold Spring 

Harbor Symposia on Quant. Biol., vol. 9, 

pp. 72-81 (1941). 
MacDowell, E. C. See Bates, R. W.; Laanes, T. 
Marvin, H. N. See Wells, B. B. 
Opdyke, D. F. See Riddle, O. 
Potter, J. S., and E. N. Ward. Mitochondria in 

lymphocytes of normal and leukemic mice. 

Cancer Res., vol. 2, pp. 655-659 (1942). 
Riddle, O. The promise of endocrinology. In 

The march of medicine, pp. 90-115. New 

York, Columbia Univ. Press (1941). 

Science in education in a democracy. 

Sci. Teacher, vol. 8, pp. 1-2, 26 (1941). 

Recognition and removal of barriers to 

effective teaching of secondary school bi- 
ology. Bull. Dept. of Sci. Instruction of the 
N. E. A., pp. 20-27 (1941). 

Amount and nature of biology teaching 

in secondary schools. In The teaching of 
biology in secondary schools of the United 
States, pp. 54-76. Lancaster, Science Press 
(1942). 



2l8 



CARNEGIE INSTITUTION OF WASHINGTON 



Riddle, O. and H. H. Dunham. Persistent ovi- 
ducts and increase of ovarian cortical tissue 
of left testis of doves at and after hatching as 
a result of estrogen passed from blood of 
mother to the egg. (Abstract) Anat. Rec, 
vol. 81, p. 29 (1941). 

Transformation of males to inter- 
sexes by estrogen passed from blood of ring 
doves to their ovarian eggs. Endocrinology, 
vol. 30, pp. 959-968 (1942). 

and J. P. Schooley. Genetic 

hermaphroditism in a strain of pigeons. 
(Abstract) Genetics, vol. 27, p. 165 (1942). 

E. L. Lahr, and R. W. Bates. The 

role of hormones in the initiation of ma- 
ternal behavior in rats. Amer. Jour. Physiol., 
vol. 137, pp. 299-317 (1942). 

— ■ and D. F. Opdyke. Gross differences in 

response of the liver to first and later daily 
dosage with insulin and prolactin. (Ab- 
stract) Federation Proceedings, Federation 
of American Societies for Experimental Bi- 
ology, vol. 1, p. 72 (1942). 

See Bates, R. W.; Wells, B. B. 



Sansome, Eva R., S. Satina, and A. F. Blakes- 
lee. Crossibility between species and be- 
tween tetraploids and diploids in Datura. 
(Abstract) Genetics, vol. 27, p. 168 (1942). 

Disintegration of ovules 

in tetraploid-diploid and in incompatible 
species crosses in Datura. Bull. Torrey Bot. 
Club, vol. 69, pp. 405-420 (1942). 

Satina, S., and A. F. Blakeslee. Periclinal 
chimeras in Datura stramonium in relation 
to development of leaf and flower. Amer. 
Jour. Bot., vol. 28, pp. 862-871 (1941). 

Contribution of the three germ 

layers to the formation of ovules in D. stra- 
monium. (Abstract) Amer. Jour. Bot., vol. 
28, p. 5s (1941). 

See Sansome, Eva R. 



Schooley, J. P. See Riddle, O. 

Seibert, H. C. See Steggerda, M. 

Steggerda, M. Maya Indians of Yucatan. xx + 

280 pp. Carnegie Inst. Wash. Pub. 531 

(1941). 
Marty Dzib — what nature means to one 

Maya Indian. Nature Mag., vol. 34, pp. 

461-464 (1941). 



— Change in hair color with age. Jour. 
Heredity, vol. 32, pp. 402-403 (1941). 

— Anthropometry of the living — a labora- 
tory manual. (Mimeographed) 55 pp. 
(1941). 

— One Maya Indian's knowledge of nature. 
Proc. 8th Amer. Scientific Cong., vol. 2, pp. 
91-92 (1942). 

— Inheritance of short metatarsals. Jour. 
Heredity, vol. 33, pp. 233-234 (1942). 

— and T. J. Hill. Eruption time of teeth 
among Whites, Negroes, and Indians. Amer. 
Jour. Orthodontics and Oral Surg., vol. 28, 
PP- 36i-37 (1942). 

and H. C. Seibert. Size and shape of 



head hair from six racial groups. Jour. 
Heredity, vol. 32, pp. 315-318 (1941). 
Sutton, E. Salivary gland type chromosomes 
in mosquitoes. Proc. Nat. Acad. Sci., vol. 
28, pp. 268-272 (1942). 

See Cole, P. A.; Demerec, M. 

van Overbeek, J., M. E. Conklin, and A. F. 
Blakeslee. Factors in coconut milk essen- 
tial for growth and development of very 
young Datura embryos. Science, vol. 94, pp. 
350-351 (1941). 

Chemical stimulation of 

ovule development and its possible relation 
to parthenogenesis. Amer. Jour. Bot., vol. 28, 
pp. 647-656 (1941). 

Cultivation in vitro of 



small Datura embryos. Amer. Jour. Bot., 
vol. 29, pp. 472-477 (1942). 

Ward, E. N. See Potter, J. S. 

Warmke, H. E. Chromosome continuity and in- 
dividuality. Cold Spring Harbor Symposia 
on Quant. Biol., vol. 9, pp. 1-5 (1941). 

A new method for determining the sex 

heterozygote in species with morphologi- 
cally undifferentiated sex chromosomes, and 
its application to Silene otites. (Abstract) 
Genetics, vol. 27, p. 174 (1942). 

Wells, B. B., O. Riddle, and H. N. Marvin. 
The Bomskov reports on thymus mediation 
of pituitary function. Proc. Soc. Exper. Biol, 
and Med., vol. 49, pp. 473-476 (1942). 



NUTRITION LABORATORY 

Boston, Massachusetts 
THORNE M. CARPENTER, Acting Director 



The research program of the Nutrition 
Laboratory has been affected by the war 
situation more seriously this year than 
last year. The defense investigation that 
was carried on during 1941 was completed 
on January 1, 1942. Since that time another 
war study has been started, and again the 
training of the personnel and the equip- 
ment at the Nutrition Laboratory have 
proved of great aid. Fortunately this 
latest investigation is resulting in the 
acquisition of information that will be 
of scientific value as well as of immedi- 
ate practical application, for it fits in 
with the Laboratory's program in opera- 



tion since its beginning, namely, the 
study of phases of the physiology of res- 
piration in relation to respiratory exchange. 
Some preliminary work has also been done 
in the way of orientation on several proj- 
ects that have developed as a result of 
previous studies in the Laboratory's re- 
search program. It is gratifying that, not- 
withstanding the pressure of the require- 
ments for war research, information is 
being acquired that will make it possible 
ultimately, when opportunity offers, to 
carry on further studies related to the 
principal objectives of research. 



STAFF NOTES 



At a meeting of the American Chemical 
Society at Atlantic City, New Jersey, on 
September 9, 1941, Dr. T. M. Carpenter 
presented a paper (jointly with V. Coro- 
patchinsky) entitled "A modified Noyons 
thermic diaferometer for respiratory gas 
analysis." This paper was part of a sym- 
posium on "New analytical tools for bio- 
logical and food research." On October 10, 
1941, Dr. Carpenter was appointed a mem- 
ber of Section B7C in Division B of the 
National Defense Research Committee. 
This superseded his appointment as a 
consultant in Section L-12 in Division B. 
On February 6, 1942, he attended as a 
delegate from the Nutrition Laboratory 
the Massachusetts Nutrition Conference, 
which was held at the Massachusetts In- 
stitute of Technology in Cambridge, Mas- 
sachusetts, at the request of Governor 
Leverett Saltonstall. 

For the meeting of the Federation of 



American Societies for Experimental Bi- 
ology, held in Boston on March 31 to 
April 4, 1942, Dr. Carpenter was Chair- 
man of the Entertainment Committee and 
Robert C. Lee served on the Personnel 
Committee. 

Dr. Carpenter's annual lecture on basal 
metabolism was given to the students of 
the Harvard Medical School on February 
27, 1942. 

Throughout the year Dr. Carpenter, 
Robert C. Lee, George Lee, and V. Coro- 
patchinsky have devoted almost their en- 
tire time to national defense projects. 

Mr. Basil James, a member of the Nu- 
trition Laboratory staff since 1929, resigned 
on November 19, 1941. Miss M. Joan 
Blakely acted as laboratory assistant in the 
metabolism tests on diabetic patients at the 
New England Deaconess Hospital from 
June 9, 1941 to November 15, 1941. Miss 
Jeannette F. Rayner was appointed on 



219 



220 



CARNEGIE INSTITUTION OF WASHINGTON 



December 8, 1941 to take her place, and has 
been carrying on the metabolism meas- 
urements full time ever since. Miss Char- 
lotte P. Curtis served as laboratory tech- 
nician, in connection with urine analyses, 



from December 3, 1941 to February 14, 
1942, and Miss Mary A. Crowley served in 
the same capacity from March 2, 1942 to 
May 29, 1942. 



INVESTIGATIONS IN PROGRESS 



Relation of the rabbit's body composi- 
tion to its basal metabolism. The chemical 
analyses of the rabbits that were used for 
the determination of the basal metabolism 
of this animal species have been completed. 
R. C. Lee has had charge of these analyses 
and has been assisted by G. Lee. 

Carbon dioxide in outdoor air. The pos- 
sibility that there are variations in the car- 
bon dioxide content of atmospheric air, 
particularly at the earth's surface, has been 
of immense interest and the object of 
many studies especially in relation to dif- 
ferent atmospheric conditions and to plant 
growth. With the gas-analysis apparatus 
and other apparatus thus far available, 
little evidence has been obtained that there 
are significant changes in the carbon di- 
oxide content of outdoor air from day to 
day. The modified Noyons diaferometer, 
the development of which was completed 
last year and a description of which was 
published this year (see p. 222), gives 
opportunity for much more refined and 
accurate determinations. During a period 
of cessation of activities in defense work, 
preliminary observations were made with 
this apparatus in a systematic way, to 
establish whether there are variations in 
the carbon dioxide content of outdoor air 
from day to day and at different times of 
the day. An attempt was also made to 
construct a volumetric gas-analysis appa- 
ratus that would be capable, theoretically, 
of measuring the carbon dioxide content 
of outdoor air with an accuracy of 0.001 
per cent. After intense effort, however, it 
was found impossible to obtain results of 



this degree of accuracy with this type of 
apparatus. In a volumetric gas-analysis 
apparatus a number of factors play a role, 
namely, changes in barometric pressure, 
changes in temperature, and changes in 
the degree of saturation with water vapor. 
Because of these factors apparently there 
are physical limits beyond which it is not 
possible to refine this type of apparatus 
and have it function accurately to give re- 
liable results. The Noyons diaferometer 
can be modified with suitable shunts in 
the galvanometer system so that the carbon 
dioxide content of outdoor air samples 
can be determined to within 0.0003 P er 
cent. Observations with this diaferometer 
have shown that there is some variation 
in the carbon dioxide content of outdoor 
air from hour to hour and from day to 
day. When opportunity presents itself, a 
systematic investigation is to be carried out 
with respect to the effects of humidity, 
barometric pressure, and wind direction 
on the carbon dioxide content of outdoor 
air. The construction of the diaferometer 
and of the volumetric gas-analysis appa- 
ratus and the observations with them were 
carried out by V. Coropatchinsky. 

Combustible gases in animal respiratory 
exchange. In the development of the modi- 
fied Noyons diaferometer it was found 
that there was not always good agreement 
in the oxygen determinations by the dia- 
ferometer and by volumetric gas analysis 
when analyses were made of samples of air 
collected from respiration chambers in 
which animals had been breathing. This 
pointed to the possible presence of an un- 



NUTRITION LABORATORY 



221 



known gas in the respiratory exchange of 
animals, in addition to the known gases 
nitrogen, carbon dioxide, and oxygen. Pre- 
liminary observations have been made this 
year with respect to the presence of a com- 
bustible gas in the respiratory exchange 
of the cat. When a gas-analysis apparatus 
adapted for the determination of com- 
bustible gases was used, it was found that 
there is a definite trace of a combustible 
gas in this animal's respiratory exchange. 
These observations will be continued when 
opportunity presents. This finding illus- 
trates one of the weaknesses of the dia- 
ferometer system, namely, that when an- 
other gas is present in an air sample in 
addition to those ordinarily present in at- 
mospheric air, the oxygen determinations 
with the diaferometer are not reliable. On 
the other hand, it shows one of the advan- 
tages of the diaferometer in helping in the 
detection of unknown gases in respiratory 
exchange. The observations with the cat 
were made by George Lee. 

Metabolism in diabetes mellitus. The re- 
spiratory exchange measurements on dia- 
betic patients have been continued this year 
through the special grant from the Car- 
negie Institution mentioned last year, and 
with the cooperation of Research Associ- 
ate Dr. Elliott P. Joslin, Medical Director 
of the George F. Baker Clinic of the New 
England Deaconess Hospital. The tests 
were made on 207 days and included 146 
patients. The various phases of the in- 
vestigation have included measurements 



of the basal metabolism of each patient on 
one or more days and, on 116 days, ob- 
servations regarding the effect on the re- 
spiratory quotient of administration of 50 
grams of dextrose. Comparisons were 
made between the effects of the oral and 
the intravenous routes for administration 
of this sugar, and in a few cases insulin 
was given along with the sugar. With 
14 patients comparisons were also made 
of the effects of ingestion of 50 grams of 
dextrose and of levulose. A study was 
made of the changes in the respiratory quo- 
tient after administration of dextrose with 
patients in diabetic coma, during severe 
acidosis, and during recovery from acido- 
sis, with patients showing resistance to in- 
sulin, and with a few during insulin re- 
action. Charts showing the combustion of 
carbohydrates in patients of different types 
were prepared and exhibited at the annual 
meeting of the Massachusetts Medical So- 
ciety in Boston on May 25 to 27, 1942, 
and at the meeting of the American Medi- 
cal Association in Atlantic City, New Jer- 
sey, on June 8 to 12, 1942. At the latter 
meeting a special certificate of merit was 
awarded to the exhibit on diabetes mellitus, 
in which these charts were included. The 
investigation has been pursued this year 
on a full-time basis with the active co- 
operation of Dr. Howard F. Root. The 
respiratory exchange measurements were 
made by B. James, M. J. Blakely, G. Lee, 
and Jeannette F. Rayner. 



PUBLICATIONS 



(1) Heat production of the rabbit at 28 C. as 
affected by previous adaptation to tem- 
peratures between 10° and 31 C. Robert 
C. Lee. Jour. Nutrition, vol. 23, pp. 83-90 
(1942). 

Twelve adult rabbits lived for stated 
periods at a given temperature between io° 
and 31 ° C. They were then kept at 28 ° and 



without food for 24 hours, and immediately 
thereafter their oxygen consumption was 
measured at 28 ° C. The heat production, 
calculated from the oxygen consumption as 
thus measured, was compared with the basal 
heat production of each rabbit predicted from 
its body weight. Five rabbits, after living for 
7 weeks at 17 C, had a heat production aver- 



222 



CARNEGIE INSTITUTION OF WASHINGTON 



aging 19.0 per cent above their average pre- 
dicted basal level. Their minimum heat pro- 
duction (7 per cent below basal) was found 
when they had been living for 3 weeks at 
31 ° after a gradual approach from lower 
temperatures to this temperature. Seven other 
rabbits that lived for 9 weeks at 10 ° and later 
for 8 weeks at 29 ° C. showed deviations from 
basal of +17.0 and —1.5 per cent, respec- 
tively. Adjustment to increase in temperature 
occurred in a shorter time than adjustment 
to decrease in temperature. The major ad- 
justment to increase in temperature toward 
thermic neutrality occurred in 2 to 3 weeks, 
but further adjustment continued for at least 
2 months. In studies concerning the effect 
of any superimposed condition on basal 
metabolism, rabbits should be kept at 28 ° to 
29 ° C. for 3 weeks prior to measurements, 
and their metabolism should be measured at 
this same temperature. 

(2) A modified Noyons thermic diaferometer 
for respiratory gas analysis. Thorne M. 
Carpenter and Vladimir S. Coropatchinsky. 
Indus, and Engin. Chem., Anal. Ed., vol. 
14, pp. 159-163 (1942). 

This modified diaferometer was designed 
primarily for analysis of respiratory chamber 
air. The apparatus has two parallel pathways 
for two continuous streams of air, which are 
driven through absorbents for both carbon 
dioxide and water vapor or through an ab- 
sorbent for water vapor alone. After passing 
through the absorbents, portions of the two 
streams of air are aspirated by a constant-level 
hydrostatic pump through chambers contain- 
ing platinum resistance wires. These wires 
form two arms of a Wheatstone bridge sys- 
tem. The differences in the cooling powers 
of the gases passing through the two sides 
of the system are measured by the deflections 
of a delicate galvanometer. The apparatus 
has been standardized by comparisons of 
analyses of diluted respiratory air and 
analyses of atmospheric air, and constants 
have been established for the equivalent per- 
centages of carbon dioxide content and oxy- 
gen deficit in samples of respiratory chamber 
air per millimeter deflection of the galva- 
nometer. The total time required for analysis 



of an air sample for both carbon dioxide 
content and oxygen deficit is about 17 
minutes; the total volume of sample required 
for the complete analysis is 1 liter. Forty-six 
consecutive alcohol control tests on 5 days 
gave an average respiratory quotient of 0.662, 
with a standard deviation of ±0.0084. The 
standard deviation of the quotients from the 
theoretical alcohol quotient of 0.667 was 
±0.0097. 

(3) The respiratory quotient of protein of the 

Dalmatian dog. Thorne M. Carpenter and 
Harry C. Trimble. Jour. Nutrition, vol. 23, 
PP- 345-349 (i942)- 
The respiratory exchange of an adult, fe- 
male Dalmatian dog was measured in two 
series of experiments 11 months apart, either 
after several days of fasting or at varying 
lengths of time after ingestion of different 
amounts of casein or raw beef. The urine 
was collected by catheterization. Most of the 
nonprotein respiratory quotients were below 
0.71. This finding could not be ascribed to 
errors in measurement, to formation of sugar 
from protein, or to excretion of uric acid, 
which is greater in this dog than in dogs of 
other breeds. As the urine did not show any 
signs of acidosis by a qualitative test and as 
the percentage of ammonia in relation to the 
total urinary nitrogen was not high enough in 
any case to indicate the presence of acidosis, it 
was assumed that the combustion of fat was 
normal. The respiratory quotients of pro- 
tein, calculated on the assumption that the 
fat metabolism was normal, were all well 
below 0.81. The hypothesis is advanced that 
the respiratory quotient of protein of the 
Dalmatian dog, although varying with the 
condition of the animal with respect to fast- 
ing and ingestion of food, is lower in general 
than the usually accepted respiratory quo- 
tient of protein, 0.81. 

(4) Carbohydrate combustion in human subjects 

after oral and after intravenous administra- 
tion of dextrose. Howard F. Root and 
Thorne M. Carpenter. Arch. Internal 
Med., vol. 69, pp. 997-1004 (1942). 

With four normal men, post-absorptive and 
sitting, the respiratory exchange was meas- 



NUTRITION LABORATORY 



223 



ured in three consecutive 10-minute periods. 
The men were then given 50 grams of dex- 
trose by mouth or intravenously, and the 
measurements were continued for nine con- 
secutive 15-minute periods. Samples of blood 
and urine were collected at intervals during 
the tests. The blood sugar was higher l /i hour 
after and lower 1 hour after intravenous in- 
jection of the dextrose than it was at the 
same times after oral administration, but 



there was no difference in the values after 
2^2 hours. Sugar appeared in the urine only 
after intravenous injection. The increases in 
respiratory quotient, oxygen consumption, 
and carbohydrate combustion for i x /z hours 
after administration of the sugar were practi- 
cally the same whether the sugar was given 
by mouth or by vein. There was a tendency 
for the increases to be insignificantly greater 
after oral administration. 



BIBLIOGRAPHY 



Carpenter, Thorne M., and Vladimir S. Coro- 
patchinsky. A modified Noyons thermic 
diaferometer for respiratory gas analysis. 
Indus, and Engin. Chem., Anal. Ed., vol. 14, 
pp. 159-163 (1942). 

and Harry C. Trimble. The respiratory 

quotient of protein of the Dalmatian dog. 
Jour. Nutrition, vol. 23, pp. 345-349 (1942). 

See Root, Howard F. 



Coropatchinsky, Vladimir S. See Carpenter, 
Thorne M. 



Lee, Robert C. Heat production of the rabbit 
at 28° C. as affected by previous adaptation 
to temperatures between io° and 31 ° C. 
Jour. Nutrition, vol. 23, pp. 83-90 (1942). 

Root, Howard F., and Thorne M. Carpenter. 
Carbohydrate combustion in human subjects 
after oral and after intravenous administra- 
tion of dextrose. Arch. Internal Med., vol. 
69, PP- 997-1004 (1942). 

Trimble, Harry C. See Carpenter, Thorne M. 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 

W. E. Castle, University of California, Berkeley, California. Experimental studies of 
heredity in small mammals. (For previous reports see Year Books Nos. 3 to 38 
and 40.) 



The investigations of the past year have 
been restricted to a further study of the 
linkage relations of genes of the rat (Rat- 
tus norvegicus). Several new mutant genes 
have been received from various labora- 
tories where the mutations have been dis- 
covered among closely bred stocks used in 
nutritional, pathological, or psychological 
studies. It is generally known that Dr. 
Helen Dean King and Dr. Castle have 
been studying linkage in the rat for some 
years and have accumulated a nearly com- 
plete assemblage of the known mutant 
genes of the rat. This knowledge has in- 
clined rat investigators not interested pri- 
marily in genetics to call Dr. Castle's and 
Dr. King's attention to promising genetic 
material which comes to their notice but 
which they are not in a position themselves 
to utilize. This kindly cooperation and 
the donation of genetic stocks are greatly 
appreciated. 

One of the most interesting of the new 
mutants was discovered and described in 
the Journal of Heredity in 1941 by Dr. R. 
O. Greep, of the Squibb Laboratories at 
New Brunswick, New Jersey. It is called 
incisorless, for the two pairs of incisors, 
which characterize the entire family of 
rodents and are of such functional impor- 
tance to them in obtaining food and as 
weapons of offense and defense, are en- 
tirely wanting in this mutant race. They 
are a kind of gnawing animal which no 
longer can gnaw. They are able to eat only 
soft or pulverized food. In competition 
with normal rats they would quickly per- 
ish in a state of nature. The mutation is 
a recessive in heredity and so true-breeding 

18 22 5 



from the start. From a single albino male 
which carried the mutant gene as a reces- 
sive but was entirely normal himself, hav- 
ing incisors as ordinary albino rats do, it 
has been possible to obtain numerous in- 
cisorless young among his second-genera- 
tion descendants. It has also been possible 
to ascertain very promptly in what chro- 
mosome the gene is borne. The latter 
shows very close linkage with the gene 
curly, which lies at one extremity of the 
second chromosome. The crossover per- 
centage with curly is apparently less than 
1 per cent. There is another mutant gene 
also closely linked with curly, namely 
anemia, with about 2 per cent of crossing 
over with curly. Crosses are now being 
made to ascertain the order of the three 
genes, which must be either Cu in an or 
in Cu an. This same second chromosome 
carries also the gene for brown pigmen- 
tation, which lies toward the opposite end 
of the chromosome. Thus we now have 4 
genes in the second linkage group, and 5 
in the first (albino) linkage group, both 
being presumably in long chromosomes, 40 
or more linkage units long. 

Loss mutations such as incisorless are 
of much interest in their possible relation 
to evolution. In the rat loss of incisors 
would be fatal in a state of nature, but 
in other mammals it is conceivable that 
such a loss would be advantageous. 
Getting rid of a useless organ is no less 
profitable in evolution than acquiring a 
new and useful one. Paleontologists tell 
us that the early proboscidians had a pair 
of incisors both above and below, like those 
of rodents but more tusklike and project- 



226 



CARNEGIE INSTITUTION OF WASHINGTON 



ing straight forward. They were prob- 
ably used in digging for roots or tubers. 
Later the tusks of the lower jaw disap- 
peared completely and only the tusks of 
the upper jaw remained, as in the extinct 
mammoths and the living elephants. It 
seems probable that the tusks of the lower 
jaw were lost by a single mutation like 
that of the incisorless rat, it being advan- 
tageous that the size and functional im- 
portance of the remaining pair of tusks be 
increased, and the other pair, now a mere 
encumbrance, be lost. 

Another loss mutation which proved 
advantageous probably occurred in the an- 
cestral history of man, namely, loss of hair 
over most of the body. Other anthropoids 
have a complete hairy coat. Doubtless 
our ancestors also had such a coat. A hair- 
less mutation in a tropical environment 
would probably be no handicap to man, 
but positively advantageous in relation to 
body parasites and protection from the 
heat, and man had sufficient ingenuity to 
devise clothing and seek out caves for 
protection from cold. Hairless mutations 
are of frequent occurrence in our labora- 
tory animals. They have been obtained 
and their inheritance has been studied in 
rats, mice, and rabbits. In each case the 
loss mutation is a simple recessive in its 
inheritance. In man the supposed earlier 



hairiness has been completely lost. There 
are no hairy humans except by an occa- 
sional possible reverse mutation, which is 
advantageous only for sideshow exploita- 
tion. 

We now have 19 rat genes to work with. 
Eleven of these are borne in three chromo- 
somes, constituting linkage groups I— III. 
Group I includes albinism, red-eyed yel- 
low, pink-eyed yellow, waltzing, and 
Griineberg's lethal. Group II includes 
curly, incisorless, anemia, and brown. 
Group III includes hairless and wobbly. 
Unassigned as yet to linkage groups are 
agouti, blue, curly 2 , jaundiced, kinky, hy- 
drocephalus, cataract, and epilepsy. The 
last three are recent acquisitions as yet 
imperfectly studied, and whether they will 
prove available for linkage studies remains 
to be demonstrated. 

BIBLIOGRAPHY 

Castle, W. E. Size inheritance. Amer. Natural- 
ist, vol. 75, pp. 488-498 (1941). 

Size genes of mice. Proc. Nat. Acad. Sci., 

vol. 28, pp. 69-72 (1942). 

Genetics of the Palomino. The Western 

Horseman, vol. 7, pp. 12-13 ( I 94 2 )- 

and Helen Dean King. Linkage studies 

of the rat {Rattus norvegicus). V. Proc. 

Nat. Acad. Sci., vol. 27, pp. 354-398 (1941). 
and P. B. Sawin. Genetic linkage in the 

rabbit. Proc. Nat. Acad. Sci., vol. 27, pp. 

519-523 (1941). 



Paul S. Conger, United States National Museum, Washington, District of Colum- 
bia. Investigations and preparation for publication of results of studies on Dia- 
tomaceae. (For previous reports see Year Books Nos. 18 to 40.) 



The work on diatoms during the past 
year centered largely on the continuation 
of several projects previously in progress, 
involving considerable investigation con- 
cerning the ecological and oceanographic 
importance of diatoms. This included a 
large amount of bibliographic work and 
organization of information with a view 
to making it more readily available. 



The advent of the war necessitated a 
considerable diversion to preparation of 
the rarer and type parts of the collection, 
and of certain irreplaceable materials for 
quick removal in case of imminent need. 

The needs of the war resulted in a 
number of unexpected and important de- 
velopments involving diatomaceous ma- 
terials or the methods of diatom research, 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



227 



and requests for information from both 
the Army and the Navy were answered, as 
well as materials examined. A number 
of these matters are strictly applicable 
to the present emergency, but in one or 
two instances there is promise of large- 
scale permanent benefits. 

General requests for information and in- 
spection of materials during the year 
seemed correspondingly increased, diato- 
maceous materials finding a number of 
new and special uses. Particularly note- 
worthy were requests for information on 
culture of diatoms to be used in physio- 
logical and other investigations. Of spe- 
cial interest were identifications made for 
Dr. Harold J. Humm, of the Duke Uni- 
versity Marine Biological Laboratory, in 
connection with his pioneering studies of 
the biological and chemical transforma- 
tions on the beaches at Beaufort, North 
Carolina. Beaches constitute one of the 
most biochemically active and significant 
of all ecological environments, and the 
diatoms are one important factor in the 
transformations that take place. 

Identifications were made for Dr. John 
Watson, of the Physics Department of the 
University of Toronto, in connection with 
investigations of the electron microscope, 
now published. New records of soil dia- 
toms for the United States were included 
in identifications made for Dr. Arlo Smith, 
of the Texas Technological College. Work 
was continued on examination of diatoms 
of the Second Byrd Antarctic Expedition. 

The course on diatoms, covering their 
biological, oceanographic, and economic 
importance, conducted for a number of 
years at the Chesapeake Biological Labora- 
tory was temporarily discontinued in the 
summer of 1942 owing to war conditions. 



In the course of investigation of the 
diatomaceous sediments of a 10-acre lake 
near Solomons Island, Maryland, a new 
and simple method was developed, and 
considerable work was done on what ap- 
pears to be a very interesting and prac- 
tically unstudied field, that of the ebulli- 
tion of gases of decomposition from lake 
waters. This process is important in the 
decomposition of lake-bottom sediments, 
which results in the concentration of their 
diatomaceous constituents through the re- 
moval of the other materials, and it is also 
important in the rapid transformation and 
release of subsequently usable substances. 
The simple device developed for collec- 
tion of such gases consisted of an inverted 
graduated tube sealed at its upper end, 
filled with water, and placed with its lower 
end passed through a supporting float and 
connected with a collecting funnel. As 
released gas bubbles arose they replaced 
water in the upper end of the tube, giving 
a daily reading of the amount of gas 
formed in a given area. By means of a 
number of these collectors anchored about 
the lake, the average production of a highly 
inflammable gas, apparently mostly meth- 
ane, was found to be 90 cubic feet per acre 
per day in August, or 900 cubic feet 
over the whole lake per day. A report of 
the various aspects of this study is in 
preparation. The writer had previously 
experienced heavy gas production from 
other dried diatom sediments through de- 
structive distillation. Examinations of the 
muds at different depths showed decided 
changes accompanying this process. 

BIBLIOGRAPHY 

Conger, Paul S. Accumulation of diatomaceous 
deposits. Jour. Sedimentary Petrol., vol. 12, 
pp. 55-66 (1942). 



228 



CARNEGIE INSTITUTION OF WASHINGTON 



Th. Dobzhansky, Columbia University, New York, N. Y. Studies on the genetic 
structure of natural populations. (For previous reports see Year Books Nos. 37 
to 40.) 



The course of biological evolution can 
be likened to a manufacturing process 
which involves three stages. The first 
stage is the production of raw materials, 
that is, of heritable variants. The heritable 
variants (gene changes and chromosomal 
aberrations) accumulate to a greater or 
lesser extent in natural populations of any 
living species. The presence of these vari- 
ants, however, does not in itself guarantee 
that evolutionary changes will take place, 
just as the mere availability of raw ma- 
terials in a factory does not guarantee the 
end product of the manufacturing process. 
The second stage entails a series of proc- 
esses which combine the variants into or- 
ganized systems, which are the hereditary 
endowments of new races and species. By 
analogy, the raw materials are thus molded 
into factory products. This is the part of 
the evolutionary process least understood. 
Finally, the third stage consists in the de- 
velopment of isolating mechanisms and 
the fixation of the nascent species. This 
stage can be compared to the packaging 
of the manufactured articles. 

The origin of heritable variants is the 
most fundamental problem of the biologist 
in his attempt to understand the mechanics 
of evolution. This problem is being stud- 
ied within the Department of Genetics of 
the Carnegie Institution of Washington 
by the group of investigators headed by 
Drs. M. Demerec and B. P. Kaufmann. 
The program of research which deals with 
the genetic structure of natural populations 
is the logical continuation of these studies. 
Inasmuch as it is established that new 
heritable variants arise from time to time 
in natural populations, their subsequent 
fate must be ascertained. This problem is, 
in turn, twofold: (1) the qualitative and 



the quantitative composition of the accu- 
mulated store of heritable variants must 
be described, and (2) their reactions to 
the various agents which impinge upon 
them must be clarified. The first is the 
static and the second the dynamic aspect 
of population genetics. For several years 
past, investigations which bear upon both 
aspects have been carried on simultane- 
ously, the fly Drosophila pseudoobscura 
serving as the test material. At present 
the work on the statics of natural popu- 
lations is approaching completion. By 
"completion" it is not meant that the 
topic has been exhausted; the writer is 
conscious of the many deficiencies in the 
available information. The data as they 
now stand are, however, adequate for a 
general outline of the situation, and from 
now on it appears more profitable to con- 
centrate on the dynamic aspect. 

Genetic variability accumulated in natu- 
ral populations. Drosophila pseudoobscura 
collected anywhere in its species area from 
British Columbia to Guatemala is singu- 
larly uniform in its structural characters. 
The observed variation is chiefly in the size 
of individuals, and most of this variation is 
nonhereditary. Only very seldom are in- 
dividuals which display obvious hereditary 
variants found. For example, among the 
thousands of wild flies which have been 
observed at Idyllwild, Mount San Jacinto, 
California, during the summer of 1942, 
the only noteworthy variants were several 
specimens with a brighter than normal 
eye color. 

This impression of uniformity is com- 
pletely reversed if, with the aid of special 
genetic techniques, individuals homozy- 
gous for different wild chromosomes are 
obtained. A majority of wild specimens 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



229 



carry various mutant genes in heterozy- 
gous condition. Some classes of mutant 
genes are amenable to exact quantitative 
estimation of their frequencies. Thus, it 
has been determined that in the wild flies 
which inhabit Mount San Jacinto, 21.3 ± 
1.8 per cent of the second, 13.9 ±1.6 per 
cent of the third, and 25.5 ± 2.2 per cent 
of the fourth chromosomes contain reces- 
sive mutant genes which are lethal or semi- 
lethal to homozygotes. Since every fly 
carries each of the above chromosomes in 
duplicate, it can be computed that only 
about 25.5 per cent of the wild individuals 
are free of lethals and semilethals; 39.4 
per cent have one, 25.0 per cent two, 8.3 
per cent three, 1.5 per cent four, 0.14 per 
cent five, and 0.01 per cent six lethals or 
semilethals concealed in their germ plasms 
(these figures replace the preliminary esti- 
mates given in Year Book No. 40). 

Furthermore, the chromosomes of many 
wild individuals carry recessive genes 
which, when homozygous, reduce the via- 
bility of their carriers to an extent which 
is perceptible but not sufficiently deleteri- 
ous to be classed as semilethal. Quanti- 
tative estimation of the frequencies of such 
genes presents serious technical difficulties 
because the magnitude of their effects var- 
ies from semilethality to a barely detect- 
able constitutional weakness. The best es- 
timates available are that 21. 1 ± 2.3 per 
cent of the second, about 30 per cent of the 
third, and about 41 per cent of the fourth 
chromosomes contain genetic modifiers 
which are to some extent deleterious to 
viability. Making the necessary computa- 
tions, we find that only 10.6 per cent of 
the flies in the natural populations are 
likely to be free from chromosomes which 
carry deleterious modifiers, and that 29.5 
per cent will carry one, 33.3 per cent two, 
19.6 per cent three, 6.2 per cent four, 1.0 
per cent five, and 0.06 per cent six such 
chromosomes. It is apparent therefore that 



perhaps no more than 2 per cent of the flies 
can be expected to be entirely free of le- 
thals, semilethals, and deleterious modifiers 
of lesser degrees. Moreover, genes, most if 
not all of which are recessive, which mod- 
ify the development rate of their carriers 
are even more widespread in natural popu- 
lations than the viability modifiers just 
mentioned. A majority of these genes act, 
when homozygous, to slow down develop- 
ment, but some of them, on the contrary, 
accelerate it. In wild populations about 
54 per cent of the second and 35 per cent 
of the fourth chromosomes contain de- 
tectable modifiers of the development rate; 
no estimate for the third chromosomes is 
available. About 13 per cent of the second 
and 8 per cent of the fourth chromosomes 
contain recessive factors which produce 
sterility of one or both sexes in the homo- 
zygotes. Finally, between 1 and 5 per cent 
of the second, third, and fourth chromo- 
somes contain recessive genes which pro- 
duce various effects on the visible morphol- 
ogy of the fly (these figures replace the 
preliminary ones in Year Book No. 40) . 

A theory of hybrid vigor. It is well 
known that inbreeding and consanguinity 
frequently result in deterioration of the 
stock, and that outbreeding is followed by 
so-called hybrid vigor or heterosis. These 
phenomena are clearly of importance in 
agriculture, as witnessed, for example, by 
the increased corn yield which is obtained 
by hybrid-corn plantings. Their sociologi- 
cal implications are probably also impor- 
tant. For more than two decades the de- 
generation which follows inbreeding and 
the increase in vigor which follows cross- 
ing have been ascribed, respectively, to 
homozygosis of concealed recessives and 
to masking of the latter by beneficial domi- 
nants. The results of analysis of wild 
populations of Drosophila pseudoobscura 
support this theory and permit further in- 
sight into the nature of heterosis. The 



230 



CARNEGIE INSTITUTION OF WASHINGTON 



great majority of the recessives found in 
the chromosomes of the fly are deleterious 
when homozygous. Moreover, very few of 
the flies in natural populations are "nor- 
mal" in the sense that they carry no con- 
cealed recessives capable of producing some 
kind of deleterious effect. The apparent 
uniformity of the individuals found in 
nature is basically a function of a great 
variety of chromosomes with different re- 
cessive mutants. Recessives may become 
homozygous and thus manifest themselves, 
chiefly through consanguinity. But the fre- 
quency of consanguineous matings de- 
pends on the effective size of the popu- 
lation and the variety of chromosomes it 
contains. The phenomena of heterosis de- 
pend therefore on the population structure 
of the species. The process of mutation 
constantly produces new genetic variants 
presumably in all species, and a majority 
of these variants are deleterious. The 
dominant and semidominant mutants are 
eliminated with relative promptness, hence 
the dominant alleles are in general more 
beneficial than the recessive ones. The 
recessive mutant alleles accumulate in the 
populations until their frequencies be- 
come sufficiently high so that homozygotes 
are produced at a rate which counterbal- 
ances the mutation frequency. The point 
at which the mutation is counterbalanced 
by elimination, in other words the equilib- 
rium point, is a function of the breeding 
structure of the species. In species which 
reproduce by self-fertilization, the genetic 
variants become homozygous and subject 
to elimination by natural selection very 
soon after their origin. In such species the 
accumulation of concealed deleterious re- 
cessives will be small, and little if any 
heterosis will be observed, since only genes 
with very mild deleterious effects can be- 
come established in any one strain. The 
same situation is expected to obtain in 
species characterized by very small effec- 



tive population size. In species with a 
greater effective population size, many 
chromosomes will contain deleterious re- 
cessives. Inbreeding in such species will 
be distinctly deleterious and outbreeding 
beneficial, but inbred strains which would 
equal in vigor the outbred strains could 
be produced by careful selection. Dro- 
sophila pseudoobscura probably falls in this 
category. Finally, in species with very 
large population sizes, most if not all 
chromosomes will accumulate deleterious 
recessives. In fact, since the effect of 
natural selection in such species is limited 
almost entirely to heterozygotes, a condi- 
tion might arise in which most of the 
genes would be represented by a multitude 
of alleles, most or all of them deleterious 
in homozygous condition. The phenom- 
ena of heterosis would be most pronounced 
in such species, and no amount of selec- 
tion would suffice to produce a fully vigor- 
ous inbred strain. Cultivated maize is 
probably an example of this last category 
of species. Because of a lack of apprecia- 
tion of their importance, however, studies 
on population structure in maize and other 
cultivated species have been neglected by 
agriculturists, and no decision can be 
reached at present concerning this subject. 
Concealed variability as a source of po- 
tential evolutionary changes. The multi- 
tude of recessives known to be carried in 
natural populations in a concealed condi- 
tion may constitute the raw materials of 
possible evolutionary changes. But the 
fact that the great majority of mutants are 
deleterious to their carriers offers a real 
obstacle to the acceptance of this view. 
The difficulty is resolved, at least in theory, 
by supposing that a mutant which is del- 
eterious in a certain environment and in 
combination with certain other genes may 
be neutral or even beneficial in other en- 
vironments and in combination with other 
genes. Experiments are in progress to test 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



231 



the validity of this supposition, which, 
unfortunately, rests on speculation rather 
than factual data. The preliminary results 
can now be outlined as follows. 

Some second and fourth chromosomes 
from wild populations of Drosophila pseu- 
doobscura contain recessive mutants which, 
when homozygous, produce deteriorations 
of viability, modifications of the develop- 
ment rate, and other changes (see above). 
Stocks of flies with such chromosomes 
have been preserved to serve for further 
experiments. Homozygotes for these chro- 
mosomes are raised at three different tem- 
peratures (16.5 , 21 , 25.5 C.) and at dif- 
ferent degrees of crowding. A technique 
is used whereby the homozygotes are made 
to develop in the same cultures with sibs 
known to have the standard viability, de- 
velopment rate, etc. The chromosomes so 
tested display a variety of behaviors. Some 
chromosomes show essentially the same 
degree of viability at all the temperatures 
and at all degrees of crowding tried; the 
viability of other chromosomes is best at 
the lowest temperature and deteriorates 
at the higher ones; still others do best at 
the intermediate temperature; but none 
which prefer the highest temperature have 
so far been detected. At the same time, 
some homozygotes show the best viability 
in sparsely populated cultures, others in 
crowded ones. The viability of a heritable 
variant is therefore not an unalterable char- 
acteristic, but a function of the environ- 
ment. The modifiers of the development 
rate have, thus far, behaved more stably. 
In other experiments, the chromosomes to 
be tested (a majority of which came from 
populations inhabiting Mount San Jacinto, 
California) are, by means of a series of 
crosses, placed onto the genetic back- 
grounds of unrelated strains. Strains de- 
rived from different parts of the distribu- 
tion area of the species, a fairly large col- 
lection of which is being kept in the 



laboratory, are used for this purpose. The 
outcome of these experiments cannot be 
reported as yet, but some data already ob- 
tained suggest that the same genetic vari- 
ant may behave differently on different 
genetic backgrounds. 

It is known that certain rare chromo- 
somes, isolated from natural populations, 
when tested in homozygous condition have 
produced not a lowering of viability but 
an increase (see Year Book No. 40). Sev- 
eral such chromosomes have been included 
in the sample which has been exposed to 
different temperatures and different de- 
grees of crowding, but not one has main- 
tained its superior-to-normal record in all 
the conditions studied. It may be regarded 
as certain that the species contains genetic 
variants which are superior to the average 
norm under certain special conditions; but 
the same variants are inferior to the norm 
in other, and presumably more prevalent, 
environments. The interest of these find- 
ings is obvious. Variants of the above 
kind may be regarded as a safety valve 
maintained by the species against the con- 
tingency of environmental change. It is 
also possible that the species contains at all 
times a variety of genotypes, some of which 
are optimal under some and others under 
other conditions of the environment to 
which the species is normally exposed in 
the course of the seasonal cycle and in 
different microclimatic and microecologi- 
cal niches. If this surmise is correct, the 
genetic composition of the species must be 
in a constant flux. Indeed, natural selec- 
tion would strive so to change the species 
genotype as to bring it up to the highest 
attainable optimum. But if the environ- 
ment should change very rapidly in rela- 
tion to the speed of reproduction of the 
organism, the latter might find itself al- 
ways close to but never quite at the opti- 
mum goal. Data indicating that such a 
state of flux actually obtains in natural 



232 



CARNEGIE INSTITUTION OF WASHINGTON 



populations of Drosophila pseudoobscura 
are available (see Year Book No. 40 for a 
preliminary report; a systematic collec- 
tion of such data continues). 

Chromosomal variants. Aside from the 
inheritable variants of genie nature, varia- 
tions in the arrangement of genes in the 
chromosomes are also found in natural 
populations of Drosophila pseudoobscura. 
This phenomenon has been studied for 
about six years; the results are described in 
a small monograph now in preparation. 
For unknown reasons, the gene arrange- 
ment is far more variable in the third than 
in the other chromosomes. The variants 
are inversions of chromosome sections. In 
the third chromosome, at least nineteen 
different gene arrangements are known. 
Their geographic distribution has been 
traced in so far as the material available 
would permit. Their phylogenetic rela- 
tionships have been established. At first 
sight, the geographic, distribution pattern 
of the different gene arrangements ap- 
pears extremely complex and irregular. 
Professor Carl Epling, of the University 
of California at Los Angeles, who has 
kindly consented to examine the pertinent 
data, has come to the conclusion, however, 
that an explanation of these complex dis- 
tribution patterns may be sought in the 
history of the species in connection with 
the geologic history of its environment, 
particularly that of the floras of the Ter- 
tiary period. The striking, and altogether 
unexpected, inference reached by Profes- 
sor Epling is that at least the phylogeneti- 
cally basic arrangements existed in geo- 
logically rather remote times, as far back 
as the Oligocene, or even earlier. 

An attempt to determine the order of 
magnitude of certain basic constants of 
population dynamics. The evolutionary 
fate of a species is determined in part by 
its intrinsic properties, its breeding struc- 
ture, and in part by the environment in 



which it lives. Among the intrinsic proper- 
ties, the following seem most important: 
(a) A species with high mutation rates 
will, in general, be more plastic than a 
species whose genes are more stable. The 
mutation rate of a gene is expressed by 
its mutability coefficient, v. (b) A large 
undivided species in which the genes dif- 
fuse freely throughout the distribution area 
is less likely to differentiate into sub- 
species than a species split up into 
local colonies exchanging individuals (mi- 
grants) at a low rate. The rate of ex- 
change of individuals between a colony 
and the rest of the species is symbolized 
by the migration coefficient, m. (c) A 
species with an effectively large panmictic 
population is evolutionarily more rigid 
than one with locally limited population 
sizes; the genetically effective population 
size is expressed by the Wright's constant, 
N. (d) Deviations from randomness of 
mating, for example frequent brother-sister 
mating, may upset the genetic equilibrium 
expected in a panmictic population. The 
degree of departure from randomness of 
mating may be expressed by the inbreed- 
ing coefficient, F. 

The lethals and semilethals present in 
natural populations constitute, for several 
reasons, favorable material for studies on 
population dynamics. Lethals found in 
natural populations may be alleles because 
(a) lethal mutations of the same gene 
may arise recurrently at different times and 
in different places, and because (b) the 
progeny of a single mutant may increase 
and spread. Independently arisen lethals 
and lethals of common origin may be dis- 
tinguished. In a large undivided species 
there should be no difference in the in- 
cidence of alleles among lethals found 
within a small territory and among those 
collected in remote territories. In such a 
species every lethal is expected to attain 
its highest possible equilibrium frequency 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



2 33 



in every part of the distribution area. Con- 
versely, restriction of the effective popula- 
tion size and migration barriers will cause 
the frequency of alleles among lethals 
within a small territory to be higher than 
that among lethals found in remote terri- 
tories. Indeed, allelic lethals found in re- 
mote territories are independently arisen 
ones, whereas within a small territory both 
independent lethals and lethals of common 
origin will be found. 

The lethals and semilethals in the third 
chromosome of Drosophila psendoobscura 
have been chosen for detailed examination. 
Samples of lethals were taken at several 
collecting "stations" on Mount San Jacinto 
and in the Death Valley region, California. 
A "station" is a territory of at most ioo 
yards in diameter. The stations on Mount 
San Jacinto are grouped in three "locali- 
ties"; the distances between stations in a 
locality are from l / & mile to 2 miles. The 
distances between the localities are from 
10 to 15 miles. Mount San Jacinto is more 
than 200 miles distant from the Death 
Valley region. The frequencies of allelism 
among lethals recovered from various pop- 
ulation samples have been determined (see 
preliminary data in Year Books Nos. 38 
and 39). The most important fact is that 
the frequency of alleles among lethals 
coming from different localities and re- 
gions is only 0.413 ± 0.081 per cent, where- 
as among lethals within a station it is as 
high as 2.13 ± 0.32 per cent. It is clear 
that Drosophila pseudoobscura is a species 
differentiated into local colonies which 
differ in genetic constitution. 

A mathematical analysis of the above 
data has been made by Professor Sewall 
Wright, of the University of Chicago. The 
conclusions are, briefly, as follows: It is 
reasonable to assume that the allelic lethals 
found in different localities and regions are 
almost entirely of independent origin. The 
frequency of alleles among independent 



lethals is a function of the number of loci 
(genes) in the chromosome capable of 
producing lethals by mutation. On the 
assumption that the mutation rates are 
uniform for all loci, and that the lethals 
produce either no effect or a uniform effect 
on viability in heterozygotes, the number 
of lethal-producing loci in the third chro- 
mosome of Drosophila pseudoobscura 
turns out to be 285 (this figure is to re- 
place the former estimate, 250, given in 
Year Book No. 38). If the above assump- 
tions are not granted, the number of the 
loci is greater than 285, which is, hence, 
the minimum estimate. A maximum esti- 
mate, arrived at by a different method, is 
approximately 1100, but for our purposes 
the minimum estimate is preferable. 

Knowing the incidence of third chro- 
mosomes carrying lethals in natural popu- 
lations and the number of mutable loci, 
it can be computed that the average fre- 
quency of a lethal in the populations of 
Mount San Jacinto is approximately 
5.23 X 10" 4 , or 0.0523 per cent. Similarly, 
knowing the rate of origin of new lethals 
by mutation (see Year Book No. 38) and 
the number of lethal-producing loci, we 
find that the average mutation rate per 
locus per generation is v = 1.077 X !0~ 5 . 
Now, in a population of a very large effec- 
tive size the equilibrium frequency of 
an autosomal recessive lethal must ap- 
proach the square root of the mutation 
rate producing that lethal. The observed 
frequency of lethals is much smaller than 
would be expected in such a population. 
This discrepancy may be brought about 
by one or by a combination of several 
causes. Among these causes, deviation 
from randomness of mating (F) and a pos- 
sible deleterious effect of the lethals in 
heterozygotes (expressed by a selection 
coefficient, s) may be important. There 
being no way to differentiate between the 
effects of F and s on the basis of the avail- 



234 



CARNEGIE INSTITUTION OF WASHINGTON 



able data, only a joint estimate of the 
value F -J- s is possible. For the popula- 
tions of Mount San Jacinto this is close to 
0.018. 

The observed difference between the 
frequencies of alleles among lethals found 
within a station on one hand and those 
found in remote localities and regions on 
the other is produced by a restriction of the 
effective population size (the Wright's 
constant, N) and a limitation of inter- 
change of individuals between populations 
inhabiting different territories (m). Again, 
the data do not permit rigorous discrimina- 
tion between these variables. In view of 
the now known relatively high mobility 
of Drosophila pseudoobscura flies (see 
Year Book No. 40), however, it may be as- 
sumed that there is a fairly free inter- 
change of germ plasms between popula- 
tions inhabiting different stations within 
a locality on Mount San Jacinto. The value 
m for stations within a locality is assumed 
to be about 0.5, which is large enough 
to give no appreciable isolation. If so, the 
Wright's constant for a station is in the 
neighborhood of 50. The mobility of the 
flies is, however, not high enough to per- 
mit an appreciable migration from locality 
to locality. Assuming m for localities to be 
less than 0.01, the value of N for the largest 
locality on Mount San Jacinto (about 6 
million square meters) is probably be- 
tween 20,000 and 30,000. 

The results reported in the foregoing 
paragraphs show how important it is to 
secure reliable information on the migra- 



tion rates of Drosophila pseudoobscura in 
its natural habitats. A series of experi- 
ments designed to clarify this problem 
have been conducted in summers of 1941 
and 1942 on Mount San Jacinto, California 
(see a preliminary report in Year Book 
No. 40). The experiments carried out in 
1942 were more successful than those of 
1941. The analysis of the resulting data 
will, however, require some time; it is 
hoped that the conclusions will be ready 
for presentation in the next annual report. 

BIBLIOGRAPHY 

Darlington, C. D., and Th. Dobzhansky. Tem- 
perature and "sex-ratio" in Drosophila pseu- 
doobscura. Proc. Nat. Acad. Sci., vol. 28, 
pp. 45-48 (1942). 

Dobzhansky, Th. On the genetic structure of 
natural populations of Drosophila. Proc. 7th 
Internat. Genetical Cong., pp. 104-108 
(1941). 

Races and methods of their study. Trans. 

New York Acad. Sci., ser. 2, vol. 2, pp. 115- 

123 (i94 2 )- 

Darwin and our intellectual heritage. 

Science, vol. 95, pp. 3°3-3°4 ( x 942). 

Foreword to Biological symposia, vol. 6, 

pp. vii-xii (1942). 

and B. Spassky. Intersexes in Drosophila 



pseudoobscura. Proc. Nat. Acad. Sci., vol. 27, 

pp. 556-562 (1941). 
Epling, C, and Th. Dobzhansky. Genetics of 

natural populations. VI: Microgeographic 

races in hinanthus Parryae. Genetics, vol. 27, 

PP- 3 r 7-332 (1942)- 
Wright, Sewall, Th. Dobzhansky, and W. 

Hovanitz. Genetics of natural populations. 

VII: The allelism of lethals in the third 

chromosome of Drosophila pseudoobscura. 

Genetics, vol. 27, pp. 363-394 (1942). 



Charles Elton, Bureau of Animal Population, Oxford University, Oxford, England. 
Research on natural fluctuations in North American animal populations. (For 
previous reports see Year Books Nos. 37 to 40.) 



The grant of the Carnegie Corporation 
of New York, through the Carnegie In- 
stitution of Washington, has again ensured 
the continuity of research into fluctuations 



in North American animals, although war- 
time research is now the main occupation 
of the Bureau of Animal Population. Mrs. 
Mary Nicholson has helped Charles Elton 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



235 



to finish a paper on the lynx cycle in 
Canada and has done the mapping for the 
two annual Canadian Wild Life Enquiries. 
The lynx paper, together with an earlier 
one on the muskrat, are the end products 
of part of a series of researches, begun in 
1925, which have involved not only the 
accumulation of annual reports through 
the Hudson's Bay Company, but an ex- 
amination of fur returns back to the eight- 
eenth century. Both species show a well 
marked ten-year cycle covering a huge 
area. Peak years are not always synchro- 
nous: in the lynx, abundance is reached 
and passed first in the northwest, some 
two or three years before other parts of 
Canada. 

Charles Elton's book Voles, mice and 
lemmings: problems in population dy- 
namics (see bibliography) includes a great 
body of new data on fluctuations in North 
American animals: in particular, on the 
short cycle in colored and arctic fox in 
the eastern Arctic and Subarctic. 



The "Canadian Arctic Wild Life En- 
quiry, 1940-41," by Dennis Chitty and 
Mary Nicholson, is in press. The year was 
remarkable for an almost universal im- 
provement in arctic fox populations. "The 
Snowshoe Rabbit Enquiry, 1939-40" was 
published early in 1942, and the reports for 
1940-41 have been mapped, but not yet 
published. A continent-wide increase in 
snowshoe rabbits was still continuing, and 
the regional occurrence of "crashes" is to 
be expected in the next few years. 

BIBLIOGRAPHY 

Chitty, Dennis, and Helen Chitty. Canadian 
Arctic Wild Life Enquiry, 1939-40. Jour. 
Animal Ecol., vol. 10, pp. 184-203 (1941). 

The Snowshoe Rabbit Enquiry, 

1939-40. Canadian Field-Naturalist, vol. 56, 
pp. 17-21 (1942). 

Elton, Charles. Voles, mice and lemmings: 
problems in population dynamics, vii + 496 
pp. Oxford, Clarendon Press (1942). 

and Mary Nicholson. Fluctuations in 

numbers of the muskrat {Ondatra zibethica) 
in Canada. Jour. Animal Ecol., vol. 11, pp. 
96-126 (1942). 



Arthur T. Hertig and John Rock, Boston Lying-in Hospital, Boston, and Free Hos- 
pital for Women, Brookline, Massachusetts. Research in embryology, embryologi- 
cal pathology, and reproductive physiology. (For previous reports see Year Books 
Nos. 36 to 40.) 



These studies on various early aspects of 
human reproduction have been continued 
with the financial support of the Carnegie 
Institution of Washington and in coopera- 
tion with its Department of Embryology. 
In addition, as in the past four years, Dr. 
Rock has received aid from the William 
F. Milton Fund of Harvard University. 

Since the last report, the authors have 
succeeded in obtaining four more stages of 
early human development, three of them 
normal and the fourth pathological. Two 
of the normal fertilized ova are younger 
than any thus far obtained, and shed light 
on the critical period immediately follow- 
ing implantation of the human blastocyst. 



These two stages are 7% and g]/ 2 days of 
age respectively. The third normal speci- 
men is approximately 11 days of age and is 
intermediate in development between the 
two normal ova of 11 and 12 days, whose 
description has been published since the 
report in Year Book No. 40 (see bibli- 
ography) . 

In this study thus far, twelve early hu- 
man ova have been recovered from uteri 
removed surgically prior to the first missed 
menstrual period. Seven of these speci- 
mens are normal and five pathological. 
Sixty-one hysterectomy cases have consti- 
tuted the clinical material which has 
yielded these specimens, an incidence of 



236 



CARNEGIE INSTITUTION OF WASHINGTON 



pregnancy in this group of approximately 
20 per cent. This fact as well as other 
clinically important features, such as the 
probable time of nidation and the location 
of embedment, were presented at the an- 
nual meeting of the American Gynecologi- 
cal Society, June 1942. From these studies 
it is concluded: (1) that ovulation occurs 
approximately 14 days prior to the next 
expected menstrual period and (2) that 
nidation takes place at a variable stage of 
development of the blastocyst, on an endo- 
metrium which may vary in phase from 
the 19th to the 22d day. Furthermore, it 
was found that the seven normal concep- 
tuses were implanted on the posterior wall 
of the uterus (without correlation as to 
the proximity of the corresponding active 
corpus luteum), whereas the abnormal ova 
were all on the anterior wall. Whether 
further specimens will make this distribu- 
tion more apparent than real is problem- 
atical, but at least it is an interesting 
observation. 

Much of this material was presented to 
the American Association of Experimental 
Pathologists in April 1942. The controlled 
experimental features of the study were 
stressed and the high proportion of 
pathological ova (42 per cent) was 
pointed out. This study indicates that 
the incidence of pathological ova is 
higher than the accepted incidence of 
spontaneous abortion of clinically diag- 
nosed pregnancies (about 10 per cent) and 
brings the results more in line with the 
high incidence of pathological pregnan- 
cies in the lower animals (30-45 per cent) . 

The corpora lutea of these early preg- 
nancies are being studied morphologically 
and a paper is being prepared for publica- 
tion. It has been found that the normal 
fatty degenerative changes in the corpus 
luteum of menstruation are prevented 
from appearing at the usual time (23 
days). This phenomenon is undoubtedly 



correlated with the implantation of the 
ovum and its effect, either direct or indi- 
rect, on the corpus luteum. 

A description of the new 11 -day ovum 
was presented before the American Asso- 
ciation of Anatomists in April 1942. At 
that time the point was stressed that the 
endometrium can be in a variable stage of 
development at the time of nidation, since 
we possess two 11-day ova of approxi- 
mately equal development whose endo- 
metria are 2 to 3 days apart in their re- 
spective stages of secretory development. 
This biological variation has been con- 
firmed and amplified in the subsequent 
finding of the "] l / 2 - and 9 1 / 4-day ova, the 
endometrium of the latter being signifi- 
cantly older than that of either of the 
1 1 -day specimens. Hence, a given blasto- 
cyst can implant on secretory endometrium 
which may vary from the 19th to 22d day 
in its secretory development, as mentioned 
above. 

Under the direction of Dr. Rock, the 
work on human ovarian ova has contin- 
ued, with the chief objective of eliciting in 
vitro fertilization. Modifications of pro- 
cedure during the past year have consisted 
in: (1) en masse culture of six to twelve 
eggs instead of manipulation of individual 
ova; (2) insemination in Locke solution 
after repeated washing of the ova; (3) 
varying the time intervals of pre-insemina- 
tion and of post-insemination culture; (4) 
repeated changing of the culture medium 
after insemination in order to avoid in- 
fection. 

BIBLIOGRAPHY 

Hertig, Arthur T., and John Rock. Two 
human ova of the pre-villous stage, having 
an ovulation age of about eleven and twelve 
days respectively. Carnegie Inst. Wash. Pub. 
525, Contr. to Embryol., vol. 29, pp. 127- 
156 (1941). 

On a series of nine human ferti- 
lized ova (5 normal and 4 pathological) 
obtained in surgically removed uteri prior 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



237 



to the first missed menstrual period. Proc. 
Federation of American Societies for Ex- 
perimental Biology, pt. 2, 29th annual meet- 
ing, vol. 1, no. 1, pp. 178-179 (1942). 



— On the eleven-day pre-villous 

human ovum with special reference to the 
variation in its implantation site. Anat. Rec, 
vol. 82, p. 420 (1942). 



Elliott P. Joslin, New England Deaconess Hospital, Boston, Massachusetts. Studies of 
carbohydrate metabolism in diabetes at the New England Deaconess Hospital. (For 
previous report see Year Book No. 40.) 



During the past year, observations on 
diabetic patients have been continued at 
the George F. Baker Clinic of the New 
England Deaconess Hospital, utilizing the 
apparatus for determination of the meta- 
bolic rate and respiratory quotient pro- 
vided by the Nutrition Laboratory of the 
Carnegie Institution of Washington. 

Patients in acute acidosis and particu- 
larly during recovery from acidosis have 
been specially studied. In addition, prob- 
lems connected with the efficiency of insu- 
lin action in relation to carbohydrate utili- 
zation have been investigated owing to 
the presence in the hospital of a number 
of patients illustrating various aspects of 
this problem. Summaries of the metabolic 
data in diabetic patients were made up in 
chart form and incorporated in an ex- 
hibit on diabetes mellitus at the annual 



meeting of the Massachusetts Medical So- 
ciety in Boston in May 1942. This same 
group of charts was used in a somewhat 
larger exhibit on diabetes mellitus which 
was presented at the meeting of the Ameri- 
can Medical Association in Atlantic City, 
June 8 to 12. This exhibit and the lectures 
connected with it received a special cer- 
tificate of merit from the judges of the 
scientific exhibit. The exhibit has been re- 
quested by the Medical Society of the 
State of Washington to form part of their 
scientific exhibit at their annual meeting 
in August at Spokane, Washington. 

BIBLIOGRAPHY 

Root, Howard F., and Thorne M. Carpenter. 
Carbohydrate combustion in human subjects 
after oral and after intravenous administra- 
tion of dextrose. Arch. Internal Med., vol. 69, 
pp. 997-1004 (1942). 



Charles W. Metz and Martha Lee Bozeman, University of Pennsylvania, Philadel- 
phia, Pennsylvania. Chromosome studies on Sciara. (For previous report see Year 
Book No. 40.) 



Evolutionary chromosome changes in 
Sciara. The remarkable opportunities pro- 
vided by the giant salivary-gland chromo- 
somes of Diptera for studies on chromo- 
some evolution have led to numerous in- 
vestigations in recent years, notably on the 
genus Drosophila. Although far from 
complete, the studies of the various investi- 
gators on Drosophila have put the study 
of chromosome evolution in that genus on 
a new basis, much more accurate than was 
possible before, and have provided a large 
body of detailed information concerning 



the changes occurring within the chromo- 
somes during the course of evolution. In 
order to evaluate the broader significance 
of the findings in Drosophila it is necessary 
to determine whether or not they apply 
also to other groups of organisms. For 
this reason we have been making an in- 
tensive study of conditions in the genus 
Sciara, a group of fungus flies far removed 
taxonomically from Drosophila. These 
flies are especially favorable for the pur- 
pose, as was pointed out in earlier pub- 
lications. In certain respects conditions in 



2 3 8 



CARNEGIE INSTITUTION OF WASHINGTON 



Sciara apparently do not conform to the 
pattern established in Drosophila, and es- 
pecial attention is being given to the points 
of difference. The major emphasis, in 
both genera, has been laid on morphologi- 
cal or quantitative chromosome changes. 
These involve rearrangement of parts 
(mainly inversion of pieces of various sizes 
within individual chromosomes) and loss 
or addition of parts. Rearrangements ap- 
pear to be characteristic of Drosophila; 
they are found commonly within individ- 
ual species and also are revealed by study 
of species hybrids. In Sciara, rearrange- 
ments apparently occur rarely in some spe- 
cies and more commonly in others. The 
reason for this difference is not yet evident. 
Rearrangements are to be expected in max- 
imum numbers in species hybrids; yet 
careful comparative study of the organiza- 
tion of homologous chromosomes in hy- 
brids between Sciara ocellaris and S. rey- 
noldsi has revealed evidence of only two 
rearrangements (inversions), involving 
only one chromosome (unpublished obser- 
vations of Dr. Pauline Rohm). In cer- 
tain other species of Sciara, however, nu- 
merous rearrangements are found simply 
by examination of wild populations within 
the individual species, as was noted in 
last year's report. 

Rearrangement of parts of chromosomes, 
unaccompanied by other changes, presum- 
ably can play only a very limited role in 
evolution. Additions of chromosome ma- 
terial, however, may provide the necessary 
basis for "progressive" evolutionary change 
in the germ plasm. As has been pointed 
out by Bridges, the "repeats" found in the 
salivary-gland chromosomes of Drosophila 
come in this latter category. They are 
relatively short regions which are present 
in duplicate within a chromosome. Pre- 
sumably they have arisen by insertion 
within a chromosome of a small part of a 
sister or homologous chromosome. Such 



"repeats" are found in small numbers in 
both Drosophila and Sciara. Especial in- 
terest attaches to the study of "repeats" 
in species hybrids, for such study gives an 
indication of how long chromosome ma- 
terial which is in duplicate, and there- 
fore presumably not subject to the effects 
of natural selection in the same manner 
as other parts, can persist without modi- 
fication. In Sciara a "triple repeat" is pres- 
ent in the X chromosome of each of the 
species mentioned above {ocellaris and 
reynoldsi). Although not yet complete 
in finer details, our study of this condi- 
tion, including study of the hybrids be- 
tween the two species, continues to indi- 
cate that the repeats are probably identical 
in the two species and hence that the con- 
dition has persisted without serious modi- 
fication of the genetic material through 
the period of evolution of these species 
from a common ancestor. 

In addition to rearrangements and "re- 
peats," there are minute modifications 
which, in a descriptive sense at any rate, 
come in other categories. They appear to 
be rare in Drosophila and relatively com- 
mon in Sciara. Some of them appear to 
involve the loss of single "bands" or disks, 
as seen in the giant chromosomes; they 
are designated "deficiencies." Others ap- 
pear to represent a doubling of single disks 
or very short chromosome regions. They 
are referred to as "duplications" and pre- 
sumably have much the same significance 
as "repeats," but their precise nature is not 
yet understood. For the latter reason, as 
well as because their mode of origin is un- 
known, these minute modifications are 
receiving especial study, particularly in 
the species hybrids mentioned above. Al- 
though this work has been extended dur- 
ing the past year, the results are not yet 
sufficiently clear-cut to warrant detailed 
discussion. 
Artificially induced chromosome changes. 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



239 



As was noted in earlier reports, the nature 
of the chromosome modifications in Sciara, 
and the relative frequencies of the differ- 
ent types as compared with those in Dro- 
sophila, make it important to get an un- 
derstanding of the chromosome mecha- 
nisms responsible for the changes. The 
best approach to this problem seems to be 
through study of artificially induced chro- 
mosome modifications, using irradiation 
and other treatments. Such a study has 
been under way for some time and has 
received particular emphasis during the 
past year. The recent experiments are re- 
viewed briefly below. In these experiments 
the treatment has been applied to the germ 
cells (mainly oocytes) and the results have 
been observed by examining the salivary- 
gland chromosomes of the Fi larvae. 

Earlier work, reported last year, indicat- 
ed that in the developing oocytes of Sciara 
ocellaris the chromosomes are resistant to 
irradiation for a considerable period, judg- 
ing by the absence of recoverable rear- 
rangements following treatment. It also 
indicated that during the period in ques- 
tion the chromosomes undergo little, if 
any, movement, which suggested that per- 
haps absence of movement is here respon- 
sible for absence of rearrangements. In 
further investigation of the problem two 
lines of attack have been followed. One 
has involved an extension of the experi- 
ments and cytological observations to other 
periods of development in order to deter- 
mine the exact limits of the "insensitive" 
period and to determine the morphological 
characteristics of the chromosomes at all 
stages in this period. The other has in- 
volved experiments designed to induce 
sensitivity to irradiation, or to induce re- 
arrangements in the chromosomes, during 
the "insensitive" period. Such studies, if 
successful, ought to aid materially in re- 
vealing the nature of the chromosome 
mechanisms in question. 



As a result of a large series of experi- 
ments, the limits of the "insensitive" period 
have now been defined with reasonable 
accuracy. In the present species the oocyte 
chromosomes are "resistant" to irradiation 
with X rays, or gamma rays of radium, 
from about the beginning of the oocyte 
growth period, during early larval life, un- 
til the second day after eclosion of the 
adult (approximately 15 days). By com- 
parison with earlier cytological observa- 
tions (Berry, 1941; Metz and Bozeman, 
1940) it is seen that this period of resistance 
coincides with a period of prolonged "pro- 
phase" during which the synapsed chro- 
mosome pairs remain in condensed long 
threads evenly spaced about the periphery 
of the nucleus. Reynolds (1941) demon- 
strated that during the second day of adult 
life of the female the unlaid eggs become 
sensitive to the effects of X rays, and that 
this sensitivity starts at about the time 
the oocyte chromosomes begin to move 
onto the spindle. 

Since one of the obvious changes asso- 
ciated with increased susceptibility to X 
rays is movement of the chromosomes, it 
was thought that rearrangements might 
be induced by combining artificially in- 
duced movement with irradiation. Experi- 
ments were carried out to test this possi- 
bility. Presumably movement alone does 
not produce aberrations, because spontane- 
ous rearrangements are rare in Sciara; 
nevertheless the possibility was tested in 
some of the experiments. 

At about 26 hours after eclosion, at 23 ° 
C, the first meiotic division begins, and 
it proceeds to first anaphase by about 29 
hours. The two groups of chromosomes 
are then well separated and remain in this 
condition until the eggs are laid, about 
24 hours later. 

It was found that the chromosomes of 
the larval oocyte nuclei could readily be 
displaced by centrifugation. A force of 



240 



CARNEGIE INSTITUTION OF WASHINGTON 



about 1700 X gravity applied for 1 hour 
will move the chromosomes into a small 
space at the centrifugal end of the nucleus. 
In this condition individual chromosome 
threads cannot be distinguished and the 
chromatin appears to be a mass occupying 
about one-tenth of the volume of the nu- 
cleus. No rearrangements were found in 
72 slides from centrifuged material. 

On the assumption that induced move- 
ment combined with radiation might be 
effective in bringing modified chromo- 
some regions or broken ends into prox- 
imity and hence provide opportunity for 
rearrangement to occur, larvae were cen- 
trifuged before and after irradiation. The 
cytological stage of every group of experi- 
mental animals was determined by ex- 
amination of ovarian smears of sister flies 
made at a time as nearly as possible coin- 
cident with the time of treatment. In the 
first such experiment, using dosages of 
1700 X gravity and 2 gram-hours exposure 
to radon, the fertility was very low and 
only 12 preparations were obtained. No re- 
arrangements were found in these. In a 
second experiment an X-ray dosage of 1980 
r units and a centrifugal force of about 
5000 X gravity were used. From material 
irradiated after centrifuging, the counts 
were as follows: 26 unaffected, 2 probably 
unaffected, and 4 unfavorable for study; 
from material irradiated before centrifug- 
ing: 60 unaffected, 8 probably unaffected, 
and 11 unfavorable. 

Though no rearrangements were de- 
tected after centrifuging and irradiating in 
close sequence, it seemed possible that the 
effect of the radiation was delayed and 
that rearrangements might occur if the 
chromosomes were brought into proximity 
at some hours after irradiation. To test 
this possibility, five experiments were car- 
ried out. A dosage of 5000 X gravity 
and of 3000 r units was used in each case. 
The results may be summarized as fol- 



lows: (1) Centrifugation l / 2 hour before 
irradiation, 8 specimens, no rearrange- 
ments; (2) centrifugation l / 2 hour after ir- 
radiation, 28 unaffected, 1 rearrangement 
(small deletion); (3) centrifugation i x / 2 
hours after irradiation, 22 unaffected; (4) 
centrifugation 4 hours after irradiation, 
25 unaffected, 1 rearrangement (reversed 
repeat); (5) centrifugation 20 hours after 
irradiation, 30 unaffected. 

The number of rearrangements found 
in this experiment is too small to permit 
the conclusion that they were induced by 
the combined treatment. They may have 
been induced by the irradiation alone or 
possibly have been spontaneous. 

Chromosome movement was also in- 
duced by immersing larvae in paraffin oil, 
which causes partial asphyxiation and ir- 
regular clumping of oocyte chromosomes, 
but no rearrangements were induced by 
this treatment (18 specimens). Larvae 
were asphyxiated and then irradiated in 
an attempt to induce rearrangements. An 
X-ray dosage of 5000 r killed all the as- 
phyxiated larvae and 17 of the 22 unas- 
phyxiated controls. The survivors were 
sterile. Two adults emerged after asphyxi- 
ation followed by irradiation with 2530 r 
units, and no rearrangements were found 
(51 specimens). 

The work just described was all done on 
larvae in which the chromosomes were 
condensed and distributed about the pe- 
riphery of the nucleus. The dosages used 
were approximately 2000 to 3000 r. A total 
of 435 Fi larvae examined showed only 
2 rearrangements. The same general cy- 
tological condition persists through the pu- 
pal stage and the first day of adult life. 
In considering later stages, especial inter- 
est attaches to the correlation between the 
mitotic activities of the chromosomes and 
susceptibility to X rays. Prepupae and 
pupae irradiated with a dosage of 4 gram- 
hours of radon showed 351 unaffected and 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



241 



1 rearrangement. Earlier work of Metz 
and Boche (1939) indicated that during 
the first day of adult life females were 
resistant to irradiation, and this observa- 
tion was supported by further work in 
which, using females irradiated at less 
than 30 hours after eclosion, there were 
no rearrangements in 56 specimens. Reyn- 
olds (1941) extended the period of ir- 
radiation into the second day of adult life. 
Rearrangements were induced at 28 hours 
after eclosion, when the chromosomes were 
"late prophase tetrads," and susceptibility 
was found to increase as meiosis progressed 
to metaphase. We have repeated this work, 
with controlled temperature of 22-23 ° C, 
using a dosage of about 11 00 r. Control 
smears showed that metaphase of the first 
meiotic division is reached at about 26 
hours. There is some variability in stage 
in any one ovary, and presumably more 
between individuals of the same age. 

Irradiation of adults younger than 22 
hours (prophase) produced no rearrange- 
ments (6 specimens) . Irradiation of adults 
22-24 hours old (beginning of prophase 
movement) produced aberrations in 4 spec- 
imens (14 per cent affected) . Irradiation of 
adults 25—26 hours old (metaphase) pro- 
duced aberrations in 9 specimens (19 per 
cent affected). Irradiation of adults 27-31 
hours old (anaphase) produced aberrations 
in 18 specimens (25 per cent affected). 
Irradiation of adults 54-55 hours old (ana- 
phase) produced aberrations in 10 speci- 
mens (50 per cent affected) . These results 
indicate that the incidence of susceptibility 
coincides with the beginning of meiotic 
movement, and increases throughout the 
meiotic period. Further experiments are 
being carried out to determine more ex- 
actly the correlation of these phenomena. 

A period of mitotic activity precedes the 

growth period of the oocytes, and larvae 

were treated during these gonial divisions 

to determine whether chromosomes at this 

19 



period were also susceptible to irradiation. 
Age is measured from the day the adults 
were mated. Hatching occurs at about 
7-8 days. A dosage of 1000 r was used. 
Irradiation of larvae 13 days old produced 

2 rearrangements, with 1 unaffected; ir- 
radiation of larvae 14 days old produced 
10 rearrangements, with 88 unaffected; ir- 
radiation of larvae 15 days old produced 

3 rearrangements, with 32 unaffected. A 
higher dosage (2500 r) was used on older 
larvae, and no rearrangements were in- 
duced in larvae 20 days old (101 speci- 
mens) ; 2 aberrations were induced in lar- 
vae 21 days old (47 unaffected). The lar- 
vae used for combinations of irradiation 
and centrifugation were 25-29 days old, 
and 2 aberrations were induced (435 speci- 
mens). The highest percentage of rear- 
rangements occurred in 13-day larvae, but 
the number of flies is too small to permit 
the conclusion that this stage is most 
susceptible. The period of sensitivity ends 
with the onset of differentiation, and al- 
most no rearrangements can be induced 
after the chromosomes become condensed 
into prophase threads. 

Although not demonstrative, evidence 
obtained in these recent experiments sug- 
gests that a correlation exists between the 
types of chromosome rearrangement se- 
cured and the stage of mitosis (or meiosis) 
at which the treatment is applied. Early 
in the study of the aberrations induced in 
young larvae, a chromosome configuration 
never before reported in Sciara was de- 
tected. This was a duplication of a seg- 
ment of chromosome, usually added so as 
to form a "direct repeat" with no interven- 
ing material. Three duplications formed 
reversed repeats similar to that described 
by Kaufmann and Bate (1938) in Dro- 
sophila. In all these duplications intimate 
synapsis occurs among all three homolo- 
gous segments. Larvae irradiated during 
the gonial mitoses probably have all 



242 



CARNEGIE INSTITUTION OF WASHINGTON 



mitotic stages present. Among 16 aberra- 
tions from such material there were 7 re- 
peats, 4 inversions, 2 translocations, and 3 
deletions. In larvae irradiated at 21 days 
(arrested prophase), 1 inversion and 1 re- 
versed repeat were found. In later larvae 
in the same cytological stage, 1 deletion was 
induced in a female, 1 reversed repeat in 
a female or male, and 1 direct repeat in 
a male. The only aberration found in off- 
spring of irradiated pupae was a translo- 
cation, but this may have been induced in 
a male. 

By the irradiation of adults 22-24 hours 
old, in which the oocytes are in prophase 
of the first meiotic division, only direct 
repeats were induced. By irradiation of 
adults 25-26 hours old, in which the 
oocytes are mainly in metaphase but also 
show some prophase and anaphase figures, 
4 direct repeats, 1 inversion, 3 deletions, 
and i repeat of a section at some distance 



were caused. By irradiation of adults 27-31 
hours old, in which the oocytes are mostly 
in anaphase, 6 direct repeats, 22 inversions, 
no deletions, 1 translocation, 3 transposi- 
tions of segments, and 3 duplications of 
segments at some distance were induced. 
By irradiation of adults 54-55 hours old, 
7 repeats, 8 inversions, and 2 deletions were 
induced. 

The lowest percentage of direct repeats 
is obtained from flies irradiated in the 
period from 27 to 31 hours (when the 
oocytes are in early anaphase), and the 
highest percentage of repeats occurred in 
flies irradiated in the period from 22 to 
24 hours (when the oocytes are in pro- 
phase). 

BIBLIOGRAPHY 

Metz, C. W. Structure of salivary gland chromo- 
somes. Cold Spring Harbor Symposia on 
Quantitative Biology, vol. 9, pp. 23-36 
(1941). 



T. H. Morgan and Jack Schultz, California Institute of Technology, Pasadena, Cali- 
fornia. Investigations on the constitution of the germinal material in relation to 
heredity. (For previous reports see Year Books Nos. 15 to 40.) 



The report by Dr. Jack Schultz which 
follows is based on the work of the period 
ending January 1942. In last year's report 
there was discussion of several series of 
experiments designed for a study of the 
functional differentiation of the chromo- 
somes. The convergent genetic, cytologi- 
cal, and cytochemical studies have been 
pursued. 

The study of the function of hetero- 
chromatin by means of the analysis of the 
variegated types of Drosophila has been 
continued. The distribution of heterochro- 
matin in the chromosomes has been stud- 
ied, by the analysis of the modifiers of the 
grade of variegation. Since the grade of 
variegation depends, other things being 
equal, on the heterochromatin balance of 
the nucleus, it was reasoned that the de- 



termination of the loci of a series of modi- 
fiers of variegation would permit the de- 
tection by genetic means of possible "in- 
terstitial" heterochromatin, in addition to 
the centromeric heterochromatin already 
studied. The experiments on the localiza- 
tion of these types have been continued, 
but are not yet ready for complete report. 
Accumulation of analyses of the many in- 
dividual cases continues, and the state- 
ment of last year's report that the ma- 
jority of the modifiers are themselves re- 
arrangements affecting centromeric hetero- 
chromatin has received supporting evi- 
dence from new cases; in addition, some 
new instances have been observed of modi- 
fiers located in the more distal regions, 
presumably in the so-called "interstitial" 
heterochromatin. 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



243 



The detailed analysis of the function of 
the heterochromatin of the second chro- 
mosome led, as was reported last year, to 
the discovery of a differentiation between 
the heterochromatin oiDrosophila melano- 
gaster and that of the closely related species 
D. simulans. It will be recalled that it was 
possible to show that striking abnormali- 
ties in the growth and differentiation of 
the organs of the hybrids were induced by 
a deficiency of the heterochromatin in the 
right limb of the second chromosome. 
Continued analysis has shown that the 
melanotic necrosis ("tumors") of the fat 
bodies (one of the characteristics in these 
crosses) may occur without the appearance 
of the duplicated organs, and that it is ap- 
parently specifically related to the rolled 
mutant. The previous work had shown 
that the hybrid males with a simulans X 
chromosome showed the "tumors" but not 
the duplicated organs. A new type of fe- 
male hybrid, containing two simulans X 
chromosomes, from the progeny of mating 
attached-X simulans females to melano- 
gaster males, displays, as the males did, 
only the "tumors," and no duplicated or- 
gans. The conclusion is therefore con- 
firmed that the X-autosome relation, and 
not the sex of the hybrids per se, deter- 
mines whether duplicated organs occur. 
Nevertheless, there is a relation between 
the melanotic "tumors" and the duplicated 
organs: the duplicated organs in these 
crosses have not been observed except in 
individuals containing "tumors" as well. 
The relation still remains to be worked 
out, since different strains of simulans dif- 
fer in their behavior in this respect. 

The question of the possible relation of 
these effects in the hybrid to the effects on 
variegation of the melanogaster deficiency 
Minute Sio has been studied. Experiments 
on the variation of the heterochromatin 
balance in relation to the effects of the 
deficiency have been carried out. The 



Minute in question is a slight type, which, 
when heterozygous for the mutant rolled, 
permits the variable manifestation of the 
rolled effects in a form not quite so ex- 
treme as the other deficiencies for the 
rolled locus. It was found that the Minute 
Sio effects themselves show some varia- 
tion with heterochromatin balance within 
the species melanogaster: the XO males 
show spread wings and their bristles ap- 
pear coarser than those of the XY males, 
with some supporting but not conclusive 
evidence that the addition of Y chromo- 
somes further intensifies the Minute ef- 
fect. It is already known that in the varie- 
gational chromosome rearrangements be- 
tween heterochromatic and euchromatic 
segments, addition of heterochromatin to 
the nucleus causes the heterochromatic 
genes brought near the euchromatin in the 
rearrangements to display the phenotype 
of the recessive mutants known at the loci 
in question. Thus the "light" locus is in 
heterochromatin, and in rearrangements 
where it is transferred to euchromatin, the 
phenotype of the heterozygote for light 
and the translocation is wild type in the 
XO male, light in the male with three Y 
chromosomes. Similarly in the present de- 
ficiency for the heterochromatin block, 
if the rolled locus were present, but un- 
dergoing a modification of function due 
to its position closer to euchromatin, it 
would be expected that addition of Y 
chromosomes to the genotype would in- 
crease the intensity of the rolled effect. 
Experiments to test this possibility have 
so far shown that this is not the case, and 
that the manifestation of rolled is the same 
in both XX and XXY individuals. There 
are, however, lethal effects, and a certain 
half-thorax type appearing in the defi- 
ciency-rolled heterozygotes, which are not 
yet explained. It is evident, however, that 
the simple postulate of an interaction in 



244 



CARNEGIE INSTITUTION OF WASHINGTON 



the hybrid between a modified hetero- 
chromatin balance and a variegational 
translocation is not sufficient to account 
for the situation. 

Last year the discovery was made that 
the heterochromatic regions divide more 
slowly in the endomitotic divisions of the 
nurse cells than do the euchromatic re- 
gions. Further evidence has been obtained 
from the study of the nurse-cell divisions 
in other species of Drosophila (virilis, ro- 
busta, simulans, pseudoobscura) that the 
picture is consistent within the genus. A 
preliminary study of Calliphora viridescens, 
however, shows a slighter difference be- 
tween the rates of division of the eu- 
chromatin and the heterochromatin of the 
nurse cells. This finding is of interest 
in connection with the work of Geitler on 
the behavior of heterochromatin in the 
endomitotic divisions of the Hemiptera, 
in which he considered the number of 
heterochromatic masses in the nucleus as 
an index of the number of endomitotic 
cycles, and found a rough correlation with 
the nuclear volumes. This offers a striking 
contrast to the picture of unequal rates 
of division in the Drosophilas. The situa- 
tion in Calliphora is apparently intermedi- 
ate between that in the Drosophilas and 
that in the Hemiptera studied by Geitler. 
It seems not unlikely that in different 
species, and perhaps within the species 
among the different tissues, the variation 
of rates of endomitotic division for the dif- 
ferent parts of the chromosomes (or the 
genes themselves) may be characteristic 
for each type of cell. 

The cytochemical analysis of the chro- 
mosomes by the combined use of staining 
technique and enzymatic digestion has 
been continued. The present series of ex- 
periments had as their object a survey of 
the differential resistance to digestion by 
the enzyme ribonuclease of nuclei at dif- 



ferent stages of mitosis, or of differing 
structural types. It will be recalled that the 
results of last year cast doubt on the re- 
puted specificity of this enzyme for ribose- 
nucleic acid, unless it were assumed that 
the structural framework of the chromo- 
somes of the salivary gland is a ribosenu- 
cleic acid. In the present study, covering 
Narcissus root tips, grasshopper and sala- 
mander testes, and sperm of Chaetopterus, 
Chiton, Ciona, Cynthia, Lytechinns, Mega- 
thura, and Patiria, as well as the eggs of 
some of these types, evidence of the same 
sort was obtained. Metaphase chromo- 
somes, the bands of the salivary-gland 
chromosomes, and highly condensed sperm 
heads such as those of Chiton and Dro- 
sophila proved most highly resistant. The 
most sensitive structures were those of the 
"resting nuclei." In the cytoplasm of the 
eggs examined, it appeared that some of 
the protein (staining with the fast green 
stain) was digested away, showing that 
other substances in addition to the ribose- 
nucleic acids of cytoplasm are affected by 
the enzyme. From these results it follows 
that during those stages of the nuclear 
cycle when the concentration of protein 
is high, either ribosenucleic acid is present 
in the chromosomes, or (in agreement with 
data of Dr. Mazia) a protein fibrous struc- 
ture in the nucleus is digested by the 
enzyme. The cytochemical data are at 
present consistent with either hypothesis, 
since the apparent correlation of ribose- 
nucleoproteins with the processes of pro- 
tein synthesis calls for their presence in the 
resting nuclei, and not in the metaphase, 
where synthesis is presumably at a mini- 
mum. 

There is a further agreement to be 
noted between these results and the recent 
application to mitosis, by Caspersson, of 
the Miescher-Kossel hypothesis of a change 
in the protein constituents of the nucleus. 



SPECIAL PROJECTS: BIOLOGICAL SCIENCES 



245 



According to this view, the complex pro- 
teins of the nucleus are broken down dur- 
ing the prophases, and the proteins re- 
maining are nucleohistones or prota- 
mines. 



BIBLIOGRAPHY 

Schultz, J. The evidence of the nucleoprotein 
nature of the gene. Cold Spring Harbor 
Symposia on Quantitative Biology, vol. 9, 

pp- 55-65 (w)- 



H. C. Sherman, Columbia University, New York, N. Y. Research on influence of 
nutrition upon the chemical composition of the normal body. (For previous re- 
ports on this and directly preceding researches, see Year Books Nos. 32 to 40.) 



From the starting point of an experi- 
mental dietary which, like many present- 
day human food supplies, was adequate 
for the perpetuation of the population in 
passable health, but suboptimal, as shown 
by its nutritional improvement under con- 
trolled conditions, the chiefly significant 
enrichments appeared to be those of cal- 
cium and riboflavin content and of vita- 
min A value. The constructive character 
of the findings with these three chemical 
factors gave rise to a new research to 
determine how far the favorable effects of 
these increased nutritional intakes can be 
explained by increased concentrations of 
these nutrients in the essential substance 
of the body. By analytical methods, 
whether of the classic type with modern 
improvements, or physicochemical, or bio- 
chemical, we seek to ascertain just what 
degrees of normal flexibility actually exist 
in the traditionally alleged fixite of the 
body's internal chemistry. The experi- 
ments with diets of different calcium con- 
tent were completed in 1941. The cor- 
responding experiments with different 
levels of nutritional intake of riboflavin 
and of vitamin A have been and are being 
continued, but in each case the rate of 
progress has been slowed down by war 
conditions, research assistants having re- 
signed to take up work on more directly 
military problems. The nutritional prob- 
lems here under consideration, however, 
undoubtedly have such significance for 
the maintenance and upbuilding of human 



health and efficiency that the fact of our 
being at war accentuates the importance 
of completing this research. 

In the experiments of the past year, a 
doubling of the riboflavin content of the 
food, within the range which supports the 
"plateau of optimal performance," has ap- 
peared to induce a slightly higher concen- 
tration of riboflavin in the liver, which 
difference increases with physical maturity; 
and a probably insignificantly higher con- 
centration in the muscles, whose riboflavin 
content seems to diminish with increasing 
age. The cases thus far studied are too 
few to permit a definite conclusion as to 
the significance of these small differences 
in the analytical findings. 

Satisfactory completion of these ribo- 
flavin studies will require extension of the 
experiments to larger numbers of cases and 
through a wider range of age, with atten- 
tion not only to the level of nutritional in- 
take of riboflavin itself, but also to that 
of phosphate and protein. The latter point 
particularly needs investigation because 
it is now known that riboflavin functions 
importantly in the tissues in combination 
with phosphate and protein. 

In the studies of the effects of enrich- 
ment of dietaries with vitamin A, the work 
of the past year indicates the importance 
of the higher intakes for the maintenance 
of full bodily reserves and optimal nutri- 
tional well-being with increasing age, even 
from earliest adulthood. Hence this part 
of the research also carries human implica- 



246 



CARNEGIE INSTITUTION OF WASHINGTON 



tions to which the war gives accentuated 
significance. 

Both the riboflavin and the vitamin A 
experiments will therefore be continued 
to the extent that the existing opportunity 
permits. 

The generous and efficient service ot 
those who have collaborated in the work 



here reported, whether as research assist- 
ants or as volunteers, is gratefully ac- 
knowledged. 

BIBLIOGRAPHY 

Sherman, H. C. Some relations of food chem- 
istry to the time of aging and the length of 
life. Amer. Chem. Soc. "News Edition," 
vol. 19, pp. 1081-1082 (1941). 



DIVISION OF HISTORICAL RESEARCH 

Cambridge, Massachusetts 
A. V. KIDDER, Chairman 



Well before the entry of the United 
States into the war it had become evident 
that the general financial situation along 
with the rapidly expanding defense activi- 
ties of the Institution would sooner or 
later necessitate curtailment or deferment 
of customary and normal research pro- 
grams. The Division's 1941-1942 program 
was accordingly formulated with a view 
to gathering as great an amount of raw 
data as possible in order that members of 
the staff not in war service might be able 
profitably to pursue their studies, for a 
relatively extended period, with a mini- 
mum of expense for field work. The 
season therefore opened earlier than usual, 
and when hostilities broke out, several 
parties were already in Central America 
and others were on the point of departure. 
Inquiry as to further procedure brought 
instructions from the Institution head- 
quarters that original plans should be fol- 
lowed; and, later, the United States lega- 
tions in the countries concerned requested 
that undertakings having value in supple- 
menting the Government's program of 
inter-American cultural relations be con- 
tinued. All scheduled explorations and 
excavations could thus be carried to com- 
pletion. When the Axis submarine cam- 
paign was extended to the Gulf of Mexico 
and the Caribbean, however, it was decided 
that irreplaceable specimens and notes 
should not be exposed to the risks of ocean 
transportation. Hence Messrs. R. E. and 
A. L. Smith, Stromsvik, Shook, Ruppert, 
and Richardson are remaining in Central 
America to work up their materials. 

An unusually large number of excava- 
tions were undertaken. In Yucatan, Dr. 



Morley cleared the elaborately decorated 
facade of a buried temple at Uxmal; 
Messrs. Brainerd and Andrews worked at 
Mayapan, Acanceh, and other ruins in the 
northern part of the peninsula, gathering 
ceramic and architectural data which will 
be of much value in interpreting the later 
prehistory of that region. In Guatemala, 
the investigation of the great archaeologi- 
cal site of Kaminaljuyu in the outskirts 
of Guatemala City was continued. Mr. 
Shook completely excavated a large mound, 
which proved to contain a superposition 
of four structures, and three tombs, one 
of them the richest in pottery and jades 
so far found at Kaminaljuyu. Mr. A. L. 
Smith worked on three of the several rec- 
tangular courts in which the ancient cere- 
monial ball game was played. These 
yielded a number of fine stone sculptures, 
mostly serpent and parrot heads with 
human faces in their open mouths. The 
Chairman devoted the season to prelimi- 
nary study of the great amounts of pottery 
recovered by Messrs. Shook and Smith. 

In Honduras, Mr. Stromsvik carried into 
its eighth year the program of excavation 
and preservation of the ruins of Copan, 
sponsored jointly by the Government of 
Honduras and Carnegie Institution. He 
completed the repair of Temple 11, now 
known, because of the long hieroglyphic 
texts adorning its walls, as the Temple of 
the Inscriptions. He also discovered south 
of the Acropolis an area containing nu- 
merous graves. As these held a great many 
mortuary vessels, representing several peri- 
ods, his collections will throw much light 
on the local sequence of pottery types. 

The excavations at San Andres, El Sal- 



247 



2 4 8 



CARNEGIE INSTITUTION OF WASHINGTON 



vador, directed by Mr. John Dimick were 
not pursued this year because of Mr. 
Dimick's entry into war service, but his 
assistant, Mr. S. H. Boggs, remained in 
Salvador to make a photographic record of 
the many large private collections of 
archaeological specimens in that country. 
Correlated with the Division's program 
was a survey of eastern Salvador by Mr. 
John M. Longyear, of the Peabody Mu- 
seum of Harvard University, a project car- 
ried out under the auspices of the Insti- 
tute of Andean Research with funds 
provided by the Coordinator of Inter- 
American Affairs. The Chairman served 
as director and visited Mr. Longyear sev- 
eral times in the field. The latter made a 
reconnaissance of the country east of the 
Lempa River, locating and mapping a 
large number of sites. He also excavated 
a small ruin at Los Llanitos, south of San 
Miguel, which proved to contain an inter- 
esting ball court, the southernmost yet 
recorded. Mr. Longyear's report will be 
issued by the Peabody Museum. 

In Nicaragua, Messrs. F. B. Richardson 
and Karl Ruppert continued the investi- 
gation at El Cauce, near Managua, where 
in 1941 Mr. Richardson discovered human 
footprints in a deeply buried layer of 
consolidated volcanic mud (Year Book 
No. 40, pp. 300-302) . The footprints were 
followed for several meters farther and a 
protective structure was erected over them. 
Mr. Ruppert devoted the season to study 
of archaeological remains in the recent de- 
posits overlying the volcanic strata. Final 
judgment as to the antiquity of the foot- 
prints must await the working-up of Mr. 
Ruppert's materials, further research on the 
volcanology of the region, and paleonto- 
logical studies bearing on the age of cer- 



tain animal tracks found by Mr. Rich- 
ardson. 

No field work in ethnology or linguistics 
was undertaken, as Drs. Redfield and Tax 
and Messrs. Villa and Rosales were en- 
gaged in preparing reports on earlier in- 
vestigations. Dr. Abraham M. Halpern 
joined the staff in 1941 to continue the 
study of Maya languages which was inter- 
rupted by the death of Dr. Andrade. Dr. 
Halpern, however, has been granted leave 
of absence for war service. 

Researches in the history of science and 
in documentary history have gone forward, 
Drs. Sarton and Pogo working in Cam- 
bridge, Dr. Stock in Washington, and Mr. 
Scholes and Miss Adams in Albuquerque, 
where Mr. Scholes also conducted a course 
in methods of archive study at the Uni- 
versity of New Mexico. Dr. Chamberlain 
is on leave of absence, acting as Senior 
Cultural Assistant in the United States 
Legation at Guatemala City. 

During the year the Division lost, 
through resignation, the services of Dr. 
Oliver G. Ricketson, Jr., a valued member 
of the staff since 1922. Dr. Ricketson ac- 
companied Dr. Morley on several journeys 
of exploration in the Peten; he was in 
charge of the initial excavations in the 
Northeast Colonnade and the Caracol at 
Chichen Itza; he investigated the ruins of 
Baking Pot, British Honduras; he inaugu- 
rated and for several years directed the 
extremely important excavations at Uaxac- 
tun in the heart of the Peten jungle. To 
Dr. Ricketson's ability as an organizer and 
leader of expeditions into difficult country, 
and to his skill as a field archaeologist, is 
due a very large share of our present 
knowledge of the Maya Old Empire. 



DIVISION OF HISTORICAL RESEARCH 



249 



ARCHAEOLOGY 



Honduras 



G. Stromsvik 



As in former years, the activities of the 
Copan expedition, a project sponsored 
jointly by the Government of Honduras 
and Carnegie Institution, comprised both 
repair of buildings and excavations with 
purely archaeological objectives. Mr. 
Stromsvik was again in charge, assisted 
by Mr. Douglas Elliott and Sr. Jesus Nu- 
nez, the latter completing the Spanish cata- 
logue of the large collection now housed in 
the Copan museum. 

The work of preservation was concen- 
trated on the Temple of the Inscriptions 
(Temple 11), which in its day was per- 
haps the most imposing of the many elabo- 
rately adorned buildings of the Acropolis, 
as it dominated both the Court of the 
Hieroglyphic Stairway and the West 
Court. In previous seasons much repair 
had been carried out on the temple proper, 
and the great range of steps mounting to 
it from the Court of the Hieroglyphic 
Stairway had been cleared of debris and 
its upper parts consolidated. Much re- 
mained to be done, however, on the other 
side, where the stairway rising from the 
West Court to the first platform and that 
from the platform to the temple were 
badly broken down. Also, the seven ter- 
races flanking the stairways had been so 
badly warped and the masonry so skewed 
by the enormous weight above them that 
it was deemed advisable to take them 
down stone by stone and rebuild them. 
As has always been Mr. Stromsvik's prac- 
tice in such work, the areas to be dis- 
mantled were carefully surveyed and pho- 
tographed, and each stone numbered 
before removal. Study of the plans and sec- 
tions made clear certain previously un- 
known features of construction, and there 



came to light, during the removal of fallen 
material, a number of fine sculptures fallen 
from the western and southern facades 
of the temple. In addition to the resetting 
of the western stairways and terraces, the 
south side of the temple substructure, the 
east half of the south stairway, and the 
southwest corner of the temple were re- 
built. 

In former years the East Court had been 
entirely cleared, save for a great pile of 
fallen masonry in the northeast corner. 
This pile not only detracted from the ap- 
pearance of the court, but offered the only 
hope of recovering sculpture from Temple 
20, the greater part of which had gradually 
been eaten away as the Copan River, be- 
fore its diversion, cut into the Acropolis. 
The heaped debris was cleared away, the 
excavation bringing to light materials 
which proved that the entire west fagade 
of the temple had fallen forward onto its 
frontal stairway. From the heap came 
several hundred pieces of carved stone, 
among them some of the finest yet found 
at Copan: geometric elements, grotesque 
animal and human forms, dozens of Ahau 
faces of various sizes, and many finely 
sculptured human heads, from half natural 
size to as much as 0.75 m. high. These 
showed such great individuality as to sug- 
gest that they were portrait studies. There 
were also recovered more fragments of the 
large bat figures found earlier at the edge 
of this heap. It is thought that the bats 
were roof ornaments, standing free atop 
the west facade. Most of the above-men- 
tioned sculpture is now arranged in rows 
along the steps of Temple 20; certain out- 
standing pieces have been moved to the 
museum. 

Another phase of preservation work was 
the solidification of the tunnel under the 
Temple of the Inscriptions, about 30 m. 



250 



CARNEGIE INSTITUTION OF WASHINGTON 



of which were lined with lateral masonry 
walls and roofed with a corbeled vault, 
to guard against possible cave-ins and 
leave the tunnel open for inspection by 
students and visitors who may wish to 
see the many interesting superimposed con- 
structions that went into the building of 
the Acropolis. Minor tasks were the re- 
pair of a large jaguar sculpture, on Plat- 
form 20, which now lacks only the head 
and the feet on the left side; and the set- 
ting upon a solid base of the gigantic head 
at the northeast corner of the Temple of 
the Inscriptions. 

The more strictly archaeological work of 
the season was largely confined to digging 
in search of burials and stratified rubbish 
deposits in the vicinity of the Acropolis. 
During the rainy season of 1941 two buri- 
als had been washed out of the riverbank 
200 m. south of the Acropolis. Following 
this lead, a trench was run west from the 
bank, revealing an extensive and long-used 
cemetery. In the excavation of no more 
than 150 cu. m. of earth 25 burials were 
found, from close to the surface to a depth 
of over 3 m. Three distinct strata were 
recognizable: the uppermost assignable 
to the late or Great Acropolis period; the 
middle to the first or Early Acropolis 
period; the lowest, in which hardly any cut 
stone was found, to the pre-Acropolis pe- 
riod. Although most of the burials con- 
tained no mortuary offerings, some were 
provided with pottery vessels and jade, 
shell, and clay ornaments. About 50 pieces 
of pottery, whole or repairable, were recov- 
ered. Most of the skeletons were so rotted 
that only the teeth could be preserved. 
A number of these were inlaid with jade. 
Burials of the three periods may be char- 
acterized as follows: 

Late or Great Acropolis period: Bodies 
usually placed flexed in rectangular ma- 
sonry cists of well squared stones. In- 
laid teeth common. Great variety of pot- 



tery types, shapes, and colors; polychrome 
abundant; Copan adaptation of Usulutan 
ware rare. Yajoa ware appears. Great 
quantities of the small, crude votive vessels 
usually called candeleros. Tentative dates 
for this period: 9.10.0.0.0 to 10.0.0.0.0 in 
the Maya time count. 

First or Early Acropolis period: Bodies 
laid flexed in open ground, occasionally 
in burial cists of cut stones. Inlaid teeth 
present. Polychrome and "Copan red" 
pottery appear; many basal-flanged bowls; 
Copan adaptation of Usulutan style com- 
mon, incised black ware common, carved 
slab-legged cylinders with lids, many can- 
deleros. Tentative dates: 8.15.0.0.0 to 
9.10.0.0.0. 

Pre-Acropolis period: Three skeletons 
found, all extended; two in crude oval 
burial cists of uncut stones and river boul- 
ders, roofed with large unshaped slabs. 
Length of skeletons as they lay in the 
ground: 1.61, 1.62, and 1.63 m. No inlaid 
teeth. Pottery: red-on-buff, ring-base 
bowls with red rim, true Usulutan plates 
with large bulbous legs, red-on-cream effigy 
jugs, carved slab-legged cylinders with lids, 
many candeleros. Tentative dates: ? to 
8.15.0.0.0. 

Metates without legs and with tapering 
handstones were common in all three 
strata, as were clay griddles. 

During the season the museum cata- 
logue was greatly amplified; many fine 
sculptures were repaired and placed on 
exhibit; and five new showcases were in- 
stalled, containing pottery, ornaments, and 
skeletal material, among which is a com- 
plete skull with inlaid teeth, of the Early 
Acropolis period. 

Yucatan: Uxmal 

S. G. MORLEY 

Dr. Morley returned to Yucatan by way 
of Mexico City in September 1941. While 



DIVISION OF HISTORICAL RESEARCH 



251 



in Mexico City he delivered a lecture at 
the University Club, for the benefit of 
British war relief, on the archaeological 
investigations of the Institution during the 
past 25 years, and repeated the lecture in 
Spanish before the Sociedad Cientifica de 
Antonio Alzate. 

During Dr. Morley's field work at Ux- 
mal in the early part of 1941, a preliminary 
examination of the Great South Pyramid, 
a high, tree-covered mound southwest of 
the House of the Governor, revealed a sec- 
tion of a collapsed corbeled vault on the 
north or front side. This confirmed an im- 
pression, formed many years ago, that near 
the summit of this pyramid there had orig- 
inally been ranges of rooms on each of 
the four sides. Dr. Morley devoted three 
weeks to excavations on all four sides of 
the pyramid, near the top, in order to 
establish the nature of the construction 
that had stood there. 

The Great South Pyramid, the highest 
and largest at Uxmal, measures 96 m. north 
and south by 80 m. east and west, and is 
27.5 m. high from the north base to the 
summit. It is built on a slope which rises 
from north to south, so that its base at 
the south is 4 m. higher than at the front. 
Two definite architectural periods were 
noted, and it is quite possible that the pyra- 
mid may contain still older constructions. 
The earliest building now visible consisted 
of a single range of at least four rooms, 
with long axes running east and west and 
doorways in their north walls. These were 
later incorporated into the northwest cor- 
ner of the pyramid, their exterior back 
walls being covered by its masonry fill. 

The pyramid proper was of eleven ter- 
races, ten at the back because of the south- 
ward rise of the terrain. The terraces, 1.42 
m. in vertical height, have battered faces. 
They are built of very roughly dressed 
stone like that of the substructure of the 
House of the Dwarf, and were finished 



with a heavy coat of lime plaster. There 
were no recessed panels or other decoration 
on the faces of these terraces. A centrally 
placed stairway on the north side, 23.5 m. 
wide, projecting from the base of the 
pyramid and having about 70 steps, gave 
access to the uppermost terrace, which was 
also reached from the back by a somewhat 
narrower stairway, asymmetrically placed 
and in two offset flights. 

On the highest terrace is a platform, 
1.32 m. high, all four faces of which are 
decorated with an elaborate sculptured 
mosaic, the principal elements being the 
lattice pattern and the familiar Maya 
grecque. The platform is ascended by rela- 
tively narrow stairways of five steps each, 
at the north and south. On the platform, 
and built around and against a solid cen- 
tral core on the top of the pyramid, are 
four ranges of rooms; that on the front or 
north side seems originally to have con- 
sisted of five nonconnecting vaulted cham- 
bers entered by doorways in their north 
walls. The east, south, and west ranges, 
however, were almost entirely solid, there 
being only a single vaulted room at the 
middle of each; the long ends of all three, 
so far as could be determined, were of 
solid masonry. These four ranges of rooms 
are 6 m. high. 

At some later time, a second outer tier 
of three vaulted rooms had been built 
in front of the three middle rooms of the 
north range. When these were added, the 
floor level of the old middle room was 
raised 1 m. above the floor level of the new 
chamber in front of it. The 1 m. from 
the floor of the outer middle room to the 
sill of the doorway of the inner room was 
sculptured with a magnificent Maya mask 
3.25 m. wide and 1 m. high, which is in a 
perfect state of preservation. Indeed, it 
seems probable that the level of the inner 
middle room was raised expressly to pro- 
vide a surface for the presentation of this 



252 



CARNEGIE INSTITUTION OF WASHINGTON 



panel, which closely resembles the mask 
panel in an identical position in the middle 
outer room of the palace at Kabah. 

The solid central core of the pyramid, 
surrounded by these four ranges, rises an- 
other 1.70 m. above the level of their re- 
spective roofs. There seems never to have 
been any construction on its summit, nor 
any stairway ascending to it from the level 
of the sculptured terrace which supported 
the rooms. 

As a second major constructional under- 
taking, the pyramid was covered from bot- 
tom to top with a layer of rubble 1.5 m. 
thick, much of it composed of dry-laid, 
large, irregularly shaped pieces of lime- 
stone. The surface of this rough covering, 
completely enclosing not only the stucco- 
faced, terraced pyramid and sculptured 
upper terrace but also the elaborately orna- 
mented facades of the four ranges of 
rooms, would also seem to have been ter- 
raced, though these later terraces are much 
broken down. 

A possible reason for the encasement of 
the pyramid and its superstructure may 
have been that the sculptured fagades of 
the four ranges of chambers had begun, 
soon after they were built, to fail, to 
crack and bulge outward so seriously that 
it became necessary, in order to keep the 
whole upper part of the pyramid from 
crashing down, to give it the support of 
added masonry, especially at the top where 
it could sustain the falling facades and 
prevent them from pushing outward. In- 
cidentally to these operations, the ranges 
of rooms were filled solidly with dry-laid 
rough rubble, and the entire construction 
was converted into a great new pyramid, 
the main stairways on its north and south 
sides still being retained. It is probable 
that eventually this larger pyramid would 
have served as substructure for some sort 
of building had not final collapse of the 
Maya in the thirteenth and fourteenth cen- 



turies halted this grandiose project before 
its crowning structure could be erected. 

Owing to the burial of the elaborately 
sculptured fagades of the building near 
the top before they had been exposed to 
much weathering, the facades were in prac- 
tically perfect preservation. The north 
fagade bears an intricate mosaic in both 
the upper and lower zones, in which 
panels decorated with geometric designs, 
grecques, and so forth appear. On the 
east, south, and west the upper zones only 
are decorated, the lower zones being of 
plain dressed stone. 

Such is the beauty of the mosaic, the 
grace of the proportions, the size and com- 
manding height of this pyramid, that it 
must, in its day, have been the most ar- 
resting building in the city. 

As nothing like complete excavation 
could be attempted in the time available, 
only such trenches were dug, on the four 
sides and at the four corners near the 
top, as would permit the making of ground 
plans and elevations. The style of archi- 
tecture indicates that the building was 
erected at the very height of the Puuc 
period, perhaps during the twelfth or 
thirteenth century. Some associated ce- 
ramic material was found, and two human 
skeletons, the bones and crania gone to 
powder. 

In addition to the work on the Great 
South Pyramid, the Northwest Group was 
entirely bushed, and a map and north- 
south cross section were made. This group 
has some of the earliest masonry found at 
Uxmal; the flat building stones are only 
very roughly dressed, and in some cases 
extend clear through the walls; both ex- 
terior and interior surfaces undoubtedly 
were plastered. 

Dr. Morley left Yucatan April 8, 1942. 
He delivered the Benjamin Franklin 
Medal Lecture before the American Philo- 
sophical Society at Philadelphia April 23, 



DIVISION OF HISTORICAL RESEARCH 



253 



and is spending the summer at Santa Fe, 
New Mexico, where he has had summer 
offices at the Laboratory of Anthropology 
for many years. 

Yucatan: Pottery 
G. W. Brainerd 

The present study of Yucatecan ce- 
ramics was begun in December 1939. The 
year 1940 was spent in Yucatan in the 
classification, tabulation, and illustration 
of the extensive sherd collections gathered 
during the previous work of the Institu- 
tion (Year Book No. 39, pp. 270-274); 
1941 in Cambridge in making chronologi- 
cal studies from previous notes, in com- 
parative work on museum and published 
material, and in preparation of the material 
for publication. 

The analysis of the pottery collections 
showed that an overwhelming percentage 
of these belong to two major periods, 
neither of which can be accurately dated 
in either the Christian or the Maya calen- 
dar, and which together represent the rela- 
tively short part of the span of human 
occupation in the Yucatan Peninsula char- 
acterized by the building of the more im- 
posing of the standing architecture. The 
two major periods represented in the ma- 
terial excavated previous to this study can 
be identified with (1) the major buildings 
in ruins of the so-called Puuc region — 
Sayil, Labna, Kabah, and Uxmal — and the 
earlier buildings at Chichen Itza; and (2) 
the later, or "Mexican," buildings at 
Chichen Itza. These periods will be called 
"Puuc" and "Mexican" respectively for ease 
of reference. In addition to these main 
groups, pottery referable to all the Peten 
periods was represented in various collec- 
tions but without definite stratigraphic 
association with the native pottery. At 
Chichen Itza there were stratigraphic evi- 
dences of a later ceramic period, the pot- 



tery of which equates with isolated frag- 
ments and specimens from widely sepa- 
rated localities in Yucatan. A considerable 
number of distinctive groups of fragments 
occur in collections which could not be 
placed chronologically from the collections 
on hand last year. The collections made 
from Oxkintok in 1940 produced a large 
sample of pottery stratigraphically proved 
to antedate the Puuc period and inferen- 
tially associated with the earlier style of 
Oxkintok architecture (E. M. Shook, Re- 
vista mexicana de estudios antropologicos, 
vol. 4, no. 3), in which a lintel dated 
9.2.0.0.0 was found. 

This year's program was planned to sup- 
plement the available material to such an 
extent that a general chronological se- 
quence, including the total span of pottery 
making on the peninsula, could be built 
up and its major periods described. It was 
also hoped that the completion of such a 
span would allow it to be dated with re- 
gard to the Maya calendar, the Christian 
calendar, or both, thus furnishing material 
to aid in the correlation of the two calen- 
dars. 

The field work during the present season 
has consisted of five trips which together 
occupied approximately three months. 
Each group of ruins investigated was 
sampled by ten to twenty trenches dis- 
tributed throughout the site. From one to 
five of these were usually found to con- 
tain large stratified deposits, the analysis 
of which served as the key by which the 
other collections from the site could be 
identified. The best sources of large, 
stratified deposits proved to be cenotes 
whenever these were present near the 
ruin. Since the end of the field trips the 
greater part of the collections has been 
classified and tabulated, and illustrations 
have been prepared for about half the ma- 
terial. Mr. R. E. Smith spent several days 



254 



CARNEGIE INSTITUTION OF WASHINGTON 



in Merida in the examination of this year's 
collections, making available to the study 
his thorough knowledge of Peten pottery 
typology. The tentative results thus far 
obtained will here be presented in the 
order of excavation. 

Yaxuna was visited. A previous sample 
excavated from this site, though small, 
shows a large variety of pottery types and 
considerable Peten contact. The larger 
collections obtained on this trip permit the 
definition of four distinct periods, charac- 
terized by changes in the basic wares. The 
first period can be equated definitely with 
the pre-Old Empire period in the Peten. 
The second seems to equate with early 
Tzakol in the Uaxactun chronology, but 
stylistically shows closer similarities to 
Early Ticoman pottery of the Mexican 
highlands. The third period appears to 
have been contemporaneous with later 
Tzakol and Tepeu I at Uaxactun. The 
last period equates with the pottery of 
the Puuc, or the earlier great building 
period at Chichen. A sculptured stela 
and a sculptured jamb were found and 
notes, drawings, and photographs made. 
Additional mapping was done on the 
site. Work of this sort was conducted at 
each site visited, including sufficient map- 
ping to locate all pottery trenches accu- 
rately. 

The site of Dzibilchaltun has not previ- 
ously been reported upon. It lies i km. 
south of the hacienda of the same name, 
and about 15 km. north of Merida. It 
consists of an aguada with a near-by ruined 
colonial church standing in the center of 
a Maya plaza. The site was suggested 
by Professor Alfredo Barrera Vasquez as 
a likely source of early colonial pottery. 
In addition to such pottery, several large 
groups of ruins, two partially standing 
Maya buildings, about 2 km. of cause- 
ways, and 22 stelae (6 of which were 
sculptured) were discovered and mapped. 



Measured drawings were made of the 
Spanish buildings and of remains of 
frescoes in the church. At one of the 
buildings a dubious sculptured date of 
1593 was found, which, however, is given 
some support by a date of 1617 dis- 
covered at the architecturally similar 
church of the neighboring village of Chab- 
lekal. Mr. E. W. Andrews took notes on 
the Maya architecture and stelae, includ- 
ing plans and sections of the two standing 
buildings. The pottery from the Maya 
ruins consists of a small collection of pre- 
Old Empire sherds, a large collection 
which seems immediately to antedate the 
pottery from the Puuc area, and a small 
collection of a period contemporaneous 
with the Mexican period at Chichen Itza. 

At Acanceh the best sherd collections 
obtained came from the base of the pyra- 
mid which is surmounted by the building 
bearing the well known stucco facade 
(Eduard Seler, Die Stuckfassade von 
Acanceh in Yucatan, Sitzungsberichte der 
Koniglichen Preussischen A\ademie der 
Wissenschaften, vol. 47, pp. 1011-1025, 
Berlin, 191 1). The collections have not 
been sorted as yet, but are known to con- 
tain material ranging from pre-Old Em- 
pire times through the Mexican period. 
The pottery resulting from Mr. Andrews' 
clearing of the buildings surmounting the 
pyramid may allow these buildings to be 
fitted into the ceramic succession. A pre- 
liminary check of the material indicates 
that collections deposited after construc- 
tion of the building with stucco fagade 
antedate the Puuc period. 

A large quantity of pottery was exca- 
vated from Mayapan, and a collection was 
obtained from the cenote of the near-by 
town of Telchaquillo. The Telchaquillo 
pottery is all post-conquest. The Mayapan 
collection contains small groups of pre- 
Old Empire and Old Empire Peten, and 
of Puuc period pottery from the bottom 



DIVISION OF HISTORICAL RESEARCH 



255 



of a trench sunk in the mouth of a cenote. 
Above this shallow deposit, pottery of the 
Mexican period of Chichen occurred 
mixed with, and finally superseded by, 
a deep deposit of redware of later date. 
A series of trenches dug near buildings 
throughout the main group of the ruin 
produced collections in which late red- 
ware preponderates. Several of the build- 
ings have since been cleared and mapped 
by Mr. Andrews. The redware found at 
Mayapan corresponds to redware of the 
latest occupation of Chichen Itza, an occu- 
pation which at the latter site left little 
pottery and few if any architectural re- 
mains. The Mayapan deposits contain a 
fine orange ware which is stylistically the 
immediate descendant of the "X" type fine 
orange found at Chichen Itza (G. W. 
Brainerd, Revista mexicana de e studios an- 
tropologicos , vol. 5, nos. 2, 3). 

The final field trip of the season was 
made to Ticul, Dzan, and Mani. Modern 
pottery making was studied at Ticul, and 
excavations were made in the environs of 
the three towns. Classification of the ex- 
tensive collections made is as yet incom- 
plete. The town cenote at Mani yielded a 
sequence ranging from a horizon to which 
we have thus far recognized no affiliations, 
through pre-Old Empire, through the 
Puuc and later periods, into heavy post- 
conquest deposits. Deposits on the grounds 
of the historic Mani church and monastery 
present an extensive Spanish colonial se- 
quence, ranging from vessels closely re- 
lated in form and ornament to Dzibil- 
chaltun specimens, up to modern times. 
These collections are rich in Mexican and 
European glazed wares, and we hope for 
accurate dating of the associated native 
wares from this part of the sample. Other 
excavations chiefly in chultuns in Dzan 
and Mani and near Ticul yielded samples 
of the Mexican, Puuc, and later redware 
periods, of which samples from this part 



of the country were previously lacking in 
our collections. 

A summary and discussion of the chro- 
nology in its present status may be set 
down here, always qualified by the unfin- 
ished nature of the work and by the spar- 
sity of samples over the large areas covered. 
During the periods above called "pre-Old 
Empire" the Yucatan Peninsula formed 
part of the range of a more or less homo- 
geneous culture, extending over a large 
area which included the Peten. A major 
part of our Yaxuna pottery of this period 
was accepted by Mr. Smith as very similar 
to the Uaxactun pottery. The Yucatan col- 
lections contain pottery of this kind from 
almost every large site sampled. Certain 
pottery types in the Yucatan sequence 
which may tentatively be equated with 
early Tzakol show definite similarities to 
central Mexican pottery of the Early 
Ticoman period. The Yucatecan periods 
which equate with Tzakol and Tepeu I 
vary throughout the peninsula, having 
but a minority of their elements in 
common with each other and with the 
Peten. Peten polychrome tradewares occur 
in small percentages, and stand out 
sharply from the native wares. The 
period herein called Puuc follows the 
above and is characterized by the domi- 
nance of slateware, the antecedents of 
which appeared in the preceding periods. 
This period is quite uniform throughout 
Yucatan, as are the following periods up to 
the conquest. 

An interesting side light on pre-Old Em- 
pire architecture is furnished by the con- 
tents of three trenches dug in the lower 
slopes of a large pyramid (15-20 m. high) 
at Yaxuna. The trenches were so dug as 
to pass through only post-constructional 
refuse and post-occupational slump. The 
pottery, beyond a few late surface sherds, 
is exclusively and typically of the pre-Old 
Empire period. Yaxuna, with its evidences 



256 



CARNEGIE INSTITUTION OE WASHINGTON 



of long and early occupation and its sug- 
gestion of influence on Chichen Itza (S. G. 
Morley, Carnegie Inst. Wash. Pub. 501, 
pp. 546-547), should certainly repay ex- 
cavation. 

Our large collections from the Puuc 
region sites of Labna, Sayil, and Kabah 
contain no pottery equivalent to that of the 
Mexican period at Chichen Itza. Uxmal 
contains only a small fraction of 1 per cent. 
Thus these sites must have been aban- 
doned before, or at the time when, the so- 
called Mexican period reached Chichen 
Itza. North of the Puuc hill range near 
Ticul, however, as well as north of Merida, 
and at Mayapan and Chichen Itza — widely 
separated sites — the Mexican period is rep- 
resented. The rise and major occupation 
of Mayapan coincided with the decline 
of Chichen Itza. This fact is proved be- 
yond reasonable doubt by stratified de- 
posits at the two sites. 

The collections on which we have 
worked until now contain no deposits 
dating from the transition between the 
Mayapan and the colonial periods. The 
color and finish of the earliest colonial 
slipped ware in our collection and that of 
the Mayapan pottery are very similar, but 
there are various changes in forms be- 
tween the two periods. The small collec- 
tions we have seen from Tulum definitely 
belong to the Mayapan period. Tulum 
was probably occupied at the time when 
the first Spaniards saw it (see S. K. Lo- 
throp, Carnegie Inst. Wash. Pub. 335, for a 
discussion of the evidence). Tradition 
places termination of the occupation of 
Mayapan at about 100 years before the 
conquest (Diego de Landa, Relacion de 
las cosas de Yucatan), and the ceramic 
evidence certainly does not refute such a 
dating. 

As can be seen from the above data, the 
purpose of this season's work is on the 
way to accomplishment. We have every 



reason to believe that by the end of the 
year a ceramic sequence equating with the 
Peten ceramic sequence and extending to 
the colonial period in Yucatan will be 
available from the material already ex- 
cavated. In addition, a re-examination of 
the long-held theory that the major cul- 
tural development of Yucatan coincided 
with the decline of the Old Empire has 
been made advisable by the increasing evi- 
dence that Yucatan supported a consider- 
able, widespread, and culturally advanced 
population during and before the time of 
the Maya Old Empire, and that this popu- 
lation in most cases used the same archi- 
tectural centers, even the same pyramids, 
as did the people of the heretofore em- 
phasized New Empire. There is no evi- 
dence of a major break in Yucatecan pot- 
tery tradition between the times of the Old 
and New Empires, and certainly no evi- 
dence of a sudden influx of Peten Old 
Empire influence during this period, when 
a migration either cultural or physical into 
Yucatan has been thought to have oc- 
curred. 

The pottery collected this season has 
added several new wares, and extensive 
data on form and decoration, to the known 
Maya ceramic repertory. Perhaps more 
important have been the stratigraphic data 
which have permitted the chronological 
placing of many kinds of pottery previ- 
ously known only from isolated sherd 
samples and whole pieces. Data on the 
variation between samples of the same 
ware gathered from various localities have 
added to our knowledge of cultural dis- 
tribution and exchange. The continuance 
of the policy of placing the architecture 
in the ceramic chronology by its accom- 
panying pottery has been made possible 
in several instances this season through 
the work of Mr. Andrews on three of the 
sites included in this report. 

This study should represent but the be- 



DIVISION OF HISTORICAL RESEARCH 



257 



ginning of more intensive and illumi- 
nating work. It has not been conducted 
as an end in itself, but as a tool to aid in 
the unraveling of the broader aspects of 
prehistory in the Yucatan Peninsula. The 
necessarily involved and time-consuming 
work now nearing completion should per- 
mit the approximate dating, or at least 
the placing in an anchored chronological 
sequence, of any ruin, standing or fallen, 
in the area. Only two of the six Yucatecan 
pre -conquest periods tentatively outlined 
in this report are at all well known, the 
Puuc and the Mexican. Architectural work 
on the immediately preceding and follow- 
ing periods has recently been begun by 
Messrs. Pollock, Shook, and Andrews. 

The present ceramic sequence is merely 
a dating outline. The order of the periods 
described has been stratigraphically proved, 
but much could be gained by further study 
of developmental changes between the pe- 
riods, cultural interconnections, regional 
variations, and craft techniques. Further 
ceramic studies should go hand in hand 
with the archaeological excavation neces- 
sary to furnish a complete picture of the 
several horizons, the chronological plac- 
ing of which has been indicated by this 
survey. 

Yucatan : Architecture 

E. W. Andrews 

It is curious that the most heavily popu- 
lated and geographically best-known sec- 
tion of the Yucatan Peninsula has re- 
mained almost entirely unstudied by the 
archaeologist. The ruins on the low plain 
to the north of the Puuc hills and to the 
west of Chichen Itza are represented in 
scientific literature by only the briefest 
references. 

During a stay in Yucatan from Decem- 
ber 1941 through June 1942, Mr. Andrews 
carried out preliminary studies at ten 
20 



ruined sites within a radius of 40 km. 
from Merida. At three of these, Mr. 
Brainerd undertook stratigraphic excava- 
tions for pottery, and at certain others 
surface collections were made and subse- 
quently examined by Mr. Brainerd. 

Perhaps most interesting of the season's 
finds was a group of sites indicating wide- 
spread architectural activity in northern 
Yucatan during early Old Empire times. 
These illustrate a style of temple architec- 
ture rigid in itself and distinct from the 
elaborate patterns of later pre-Mexican 
construction on the northern part of the 
peninsula. The chronological separation 
of the distinctive early and late styles is at- 
tested by actual superposition of build- 
ings, the occurrence of transitional forms, 
and the association of distinct pottery 
types with the two architectural styles. 

The early architecture is distinguished 
by a special structural technique. Wall 
masonry is of large, roughly faced blocks, 
leaving little or no space for cement heart- 
ing between the two faces. Vaults are 
of deeply tenoned flat slabs, apparently 
never pre-shaped, set in roughly corbeled 
courses with much fine rubble and cement. 
Wall faces are evened with considerable 
spalling, but vault faces are composed 
entirely of it, as the crude ends of the flat 
slabs offer no regular surface. Wall and 
vault surfaces were finished with a thick 
coat of plaster. Neither wall nor vault 
shows any suggestion of veneer. 

The form achieved is both constant and 
simple. Basal moldings either are absent 
or are composed of a single course of rough 
blocks. Medial and superior moldings con- 
sist of a single rectangular member. The 
upper facade is normally covered with 
stucco designs in deep relief, which often 
extend onto the moldings. Carved stone 
is never used in facade decoration. 

Later pre-Mexican architecture of the 
region is characterized by the use of very 



2S8 



CARNEGIE INSTITUTION OF WASHINGTON 



finely squared and faced stone in a thin 
veneer over a rubble core, both in wall and 
in vault. No spalling was needed, and a 
thin coat of plaster sufficed to form a very 
smooth surface. Basal moldings, usually 
complex, are almost universal. Medial and 
superior moldings follow a three-member 
pattern, the upper and lower elements 
triangular in section. The upper facade is 
characteristically heavily adorned with 
mask panels or a variety of designs made 
up of a mosaic of small carved elements; 
where stucco relief is found, it is secondary. 
Excavations in a small section of the 
acropolis at Acanceh revealed that the fa- 
mous temple with the stucco reliefs be- 
longs to the earlier pattern. It was origi- 
nally built close to the north edge of a 
truncated pyramid about 8 m. high. Later, 
the platform was extended some 60 cm., 
and a new face added to the pyramid, the 
sides of which were covered with white 
stucco and painted with designs in red. A 
further stage of construction extended the 
platform a considerable distance farther 
north; and on this addition, some 50 cm. 
above the original floor level, was built 
the long, narrow building facing the 
Stucco Temple. The new edifice, al- 
though retaining the essential block-wall 
and slab-vault structural technique, varied 
somewhat in external form. It stood on a 
35-cm.-tall, single-member basal molding, 
and although retaining the simple rec- 
tangular medial and superior moldings, 
replaced the strongly retreating upper 
facade of the Stucco Temple with a taller 
vertical one. Excavation showed that dur- 
ing the use of the court between these two 
structures, the floor level was raised five 
times. Finally, both temples were filled 
with rubble, their doorways were sealed 
with masonry of the early type, and the 
entire area was filled in to the level of 
the roofs to serve as foundation for build- 
ings in the later architectural style. This 



final phase is represented by no standing 
rooms on the acropolis, but is evident from 
an abundance of carved stone facade orna- 
ments, typical veneer wall blocks, finely 
cut, deeply tenoned vault stones, and full- 
width doorjambs. Associated with each of 
the developmental phases mentioned were 
sealed deposits containing potsherds which 
should be correctable with Brainerd's 
more extensive stratigraphic material from 
the slopes of the acropolis. A preliminary 
examination indicates the probability that 
all stages through the filling-up of the 
court between the two early temples belong 
to pre-Puuc times. It is probable, more- 
over, that the large pyramid in the city 
plaza, originally covered by a later struc- 
ture but now considerably exposed, also 
belongs to the early horizon. Visible frag- 
ments are characterized by the use of 
inset stairways, rounded, inset corners, a 
lack of finely cut stone, and the use of 
large panels of stucco relief. The plan is 
strongly reminiscent of that of early Peten 
substructures. 

As early as 191 1, Seler suggested that the 
buildings at Acanceh were earlier than 
those generally known in Yucatan. He 
also pointed out a strong resemblance be- 
tween Acanceh architecture and that of 
Ake and Izamal to the north, and sug- 
gested that the latter sites might be as- 
signed to an early period. Acanceh and 
Ake, both large ruins, are conspicuously 
ignored in the conquest-period historical 
traditions of the local natives. Landa states 
in regard to Izamal, "There is no remem- 
brance of their builders and they appear 
to have been the first." During the present 
season, brief visits were made to Izamal 
and Ake. The majority of remains at both 
sites are definitely not in the Puuc tradi- 
tion, which is easily recognizable even in 
the debris of wholly fallen buildings. Nor 
do they consist of the entirely uncut stone 
whose use followed the abandonment of 



DIVISION OF HISTORICAL RESEARCH 



259 



fine veneer in Yucatan. Substructures 
and, in some cases, buildings were made 
of great, roughly faced cubical blocks dif- 
fering only in size from those of Acanceh 
and other early sites. The stucco decora- 
tion of the Izamal pyramids is remark- 
ably similar to that of the mound in the 
plaza at Acanceh. Finally, Brainerd states 
that sherds from below the plaster floor of 
one of the final additions to the mound 
complex south of the Convent of San 
Antonio at Izamal are referable to the 
basal-flange horizon in the Peten. This ref- 
erence is paralleled by the orderly distribu- 
tion of ruins at Ake around rectangular 
plazas, an arrangement characteristic of 
the Peten sites but not found in the cities 
of the Puuc and Mexican horizons in 
Yucatan. 

Evidence that these differences are 
chronological rather than geographical is 
to be found at Cuca, 10 km. east of Ake. 
Here the remains are entirely of buildings 
in highly evolved Puuc style with no trace 
of the megalithic or block construction dis- 
cussed above. 

Ten days were spent at the ruins of 
Dzibilchaltun (also locally known as 
Xlacah), 15 km. north and slightly east of 
Merida, where Brainerd was conducting 
ceramic excavations. One standing temple 
there belonged clearly to the early style 
both in structural technique and in ex- 
ternal form. But a number of minor traits 
hinted a possible developmental transition 
to the Puuc style. The structure had a low 
basal molding, and the wall stones were 
more finely cut than those of Acanceh, al- 
though showing no tendency toward ve- 
neer. The spring course of the vault was 
of very carefully faced stone, in strong con- 
trast with the rough slabs of the vault itself. 
The end walls carried a thin false vault 
spring, a characteristic of Puuc architecture 
found in neither of the early temples at 
Acanceh. Pottery from between two floors 



in one of the rooms has been tentatively de- 
scribed by Brainerd as immediately ante- 
dating that found in the Puuc sites. This 
earlier architecture seems to have included 
the greater part of the construction at 
Dzibilchaltun. Visible fragments of a 
filled-in and almost completely buried 
structure in another part of the site show 
identical masonry and outer facade form, 
and indicate that at least large parts of an 
elaborate stucco facade similar to that at 
Acanceh remain intact under later con- 
struction. Other lower wall and vault frag- 
ments are in this tradition, and the general 
plan of the site is characterized by Peten- 
like aggregations of mounds around or- 
derly plaza systems. However, a few carved 
facade stone elements strongly reminiscent 
of Mexican-period Chichen Itza art be- 
speak at least some later occupation. These 
remains are very common in a single court 
at the eastern edge of the site, and rather 
rare elsewhere. Although a number of 
glyphic stelae are too badly damaged to 
offer any hope of translation, it is clear that 
none carried Initial Series. 

About 40 km. west and slightly south of 
Merida and 6 km. southwest of Kinchil 
are the ruins of Tzeme, a very large site, 
covering several square kilometers. A 
large part of the town of Kinchil and the 
neighboring hacienda of Santa Maria has 
been built with stone taken from its mon- 
uments; and two grotesque life-size hu- 
man statues from Tzeme have been re- 
moved to the Merida Museum. Although 
no standing buildings remain, two periods 
of occupation are evident. At the center of 
the site is a group of tall pyramids around 
a rectangular plaza. Near by are several 
groups of lower pyramids similarly ar- 
ranged around smaller plazas. Atop these 
mounds are vestiges of small structures in 
the block-wall and slab-vault tradition, en- 
tirely lacking carefully cut stone. In the 
center of the plazas, however, and scat- 



260 



CARNEGIE INSTITUTION OF WASHINGTON 



tered outside the central area are numerous 
remains of distinct rubble-and-veneer struc- 
tures with carefully squared full-width 
jambs, specialized vault blocks, and a va- 
riety of sculptured facade elements. These 
buildings clearly belong to either the Puuc 
or the Chichen Mexican period. 

Reports were received of the small site of 
Chuhku, about 15 km. southeast of Tzeme, 
containing at least one well preserved 
standing temple. Many residents of Kin- 
chil can serve as guides. 

Through the kindness of Don Fernando 
Cervera, it was possible to spend a number 
of days at the large ruins on the Hacienda 
Yaxcopoil, 25 km. south and slightly west 
of Merida. The ruins, about 1500 m. east 
of the hacienda buildings, seem to have 
been occupied from very early times 
through the Puuc and Chichen Mexican 
periods. Although no excavation was un- 
dertaken, much pottery from the latter 
periods was found on the surface. A small 
amount of red lacquer ware may indicate 
a short overlap into the last phase of pre- 
Spanish culture, or a small continuous 
population in that era. The central group 
of ruins is distributed around a long, nar- 
row plaza, at one end of which is a pyra- 
mid approximately 12 m. high, ascended 
by four stairways. Atop the complete ruin 
of the superstructure is a geographical 
bench mark with the legend N 20 45' 05", 
W 89 ° 42' 18". This large mound is called 
Tanmul, meaning "Central Pyramid," by 
which name the site is occasionally known. 
Present superstructure debris in the cen- 
tral group is characterized by a quantity of 
veneer stone, but this may be of secondary 
origin. About 250 m. south of this com- 
plex is a large, low platform mound bor- 
dered by four ranges of rooms surrounding 
a central court. Several rooms of the 
northern range are still standing and lo- 
cally called Aka'na ("House in the Dark"), 
by which name the whole site has also 



been known. Several phases of construc- 
tion are apparent. An original five-room 
structure was built in style clearly transi- 
tional between the early and Puuc periods. 
The lower walls are faced with a poorly 
cut, irregular veneer, but the vault is made 
of flat, almost unfaced blocks so crudely 
set that the face consists largely of spalling. 
Moldings are complex but still rectangular 
in section, varying in form as a support 
for elaborate panels of deep relief in 
painted stucco which cover the upper 
facade zone. There is no carved stone. In 
two later stages, a series of rooms was 
built around this unit in a very different 
manner. Their rubble walls bear a thin 
veneer of finely cut, beautifully squared 
stone laid in perfect courses. Vaults are of 
the characteristic "boot-shaped" and bev- 
eled blocks, equally carefully set; and the 
upper facade zone was covered with panels 
and masks in carved stone mosaic. The 
outer corners bear on each face a line 
of carved rosettes from medial to basal 
molding. The doors, simple in the interior 
structure, become triple, with jambs and 
round pillars carved in typical Puuc style. 
The Aka'na will richly reward future ex- 
cavation, for in the construction of the 
later rooms, the stucco facade of the older 
temple was carefully sealed in and re- 
mains largely intact. Remains of the later 
Puuc period architecture are distributed 
generously over the site, as are those of 
the following era of Mexican influence. 
Several long, low mounds bear a central 
row of altars formed of crudely cut mega- 
liths, and have no trace of further masonry 
superstructure. Another common form of 
building is the round-columned, flat-roofed 
colonnade of Mayapan type, whose walls 
(as at Mayapan) are of crude block rather 
than veneer masonry. This fact, in connec- 
tion with the small amount of red lacquer 
ware in surface pottery, indicates Yaxco- 
poil's importance for future study as pos- 



DIVISION OF HISTORICAL RESEARCH 



26l 



sibly spanning the gap between the veneer 
tradition of the Puuc and Chichen Mexi- 
can periods and the uncut block masonry 
which later replaced it. This possibility 
is not known to exist at any other site 
on the peninsula. 

Minor excavations were undertaken at 
one further ruin apparently occupied in pre- 
Puuc times. This site, 500 m. east of the 
Merida-Uxmal highway at Kilometer 39.5, 
is on the hacienda of Sihunch'en, whose 
name it has been given. Recently there 
were a number of standing buildings, but 
these have been in large part demolished 
and their stone ground up to resurface the 
near-by highway. Fragments of two build- 
ings were left, both of which seem to be 
in the earliest architectural tradition. Walls 
are of large, coarse blocks with no rubble 
fill, vaults of the familiar unprepared flat 
slabs. No basal molding was used. Medial 
and superior moldings were one-member 
and rectangular. As usual, a lack of cut 
stone accompanies an elaborate stucco 
facade, in this case largely fallen. One 
building had but a single long, narrow 
room, colonnaded in front with very 
crudely rounded stone columns without 
pedestal but with a roughly squared capi- 
tal, on which rested very crude stone lin- 
tels. The total door height was only 122 
cm. Masonry in both buildings is much 
cruder than any observed elsewhere dur- 
ing the present season. It may reflect rela- 
tive antiquity, or merely a lack of archi- 
tectural skill at this small site. Not enough 
pottery was found to offer much clue to 
dating, although a few sherds were of 
pre-Mexican slate which could be assigned 
to either Puuc time or slightly before. 

Another period of Yucatan history came 
under study in the course of a month's 
work at the ruins of Mayapan. Eight 
buildings were either largely or entirely 
cleared; and a number of minor excava- 
tions served to round out the picture thus 



obtained. The site and its surrounding 
wall were mapped by Patton in 1938 (cf. 
Year Book No. 37, pp. 141-142). 

A minor early occupation of the site 
is indicated by a number of re-used, finely 
cut stones in the buildings of the central 
group. No structures of this period re- 
main, however, although it is possible that 
an unexcavated interior building immedi- 
ately below the present superstructure of 
the Pyramid of Kukulcan (Structure 10) 
may belong to that horizon. These re- 
mains probably correspond to an under- 
lying stratum of pottery (about 8 per cent 
of the whole) found by Brainerd to be 
similar to that of the Mexican period at 
Chichen Itza. 

The vast majority of remains at the site 
consist of small unit shrines and colon- 
naded palace-type structures employing 
either thin-drummed round columns or 
anthropomorphic supports for flat beam- 
and-mortar roofs, as did a few atypical 
structures whose plans were almost cer- 
tainly copied from Chichen Itza proto- 
types. The resemblance of the large round 
tower at Mayapan to the Caracol at 
Chichen has often been mentioned. The 
latest superstructure of the great pyramid 
at Mayapan is identical in plan with the 
Chichen Castillo, although very differently 
constructed and with unvaulted roof. Two 
small round temples excavated had ground 
plans similar to that of the Casa Redonda 
at Chichen. 

Except where a few stones were re-used 
from the earlier period mentioned, both 
walls and vaults at Mayapan were con- 
structed of completely uncut, rough blocks, 
with no tendency toward veneer. No 
prepared outer face is recognizable on 
blocks in fallen debris, and the absence of 
cubical form made coursing next to im- 
possible. Although no facades at Mayapan 
stand as high as the medial molding, it 
is evident from debris that the profile was 



262 



CARNEGIE INSTITUTION OF WASHINGTON 



normally that of a single two- or some- 
times three-member molding with re- 
stricted upper zone, and the elaborate 
carved stone mosaic so typical of earlier- 
period facades was absent. 

The major occupation of Mayapan may 
be clearly assigned to a period later than 
that which at Chichen Itza is represented 
by the architectural efforts seen at the ball 
court, Castillo, Temple of the Warriors, 
and related structures. But certainty as to 
whether architectural effort had entirely 
ceased at Chichen during the Mayapan 
period must await the discovery of specific 
associations between certain late structures 
at Chichen (the Temple of the Initial Series, 
the Temple of the Interior Atlantean 
Columns, etc.) and deposits of pottery 
from one of the two periods. Although 
certain of the larger temples at Mayapan 
undoubtedly drew inspiration for their 
plan directly from Chichen, the construc- 
tional techniques of the two sites are un- 
compromisingly distinct. The earlier ve- 
neer traditions persisted at Chichen 
through the end of architectural activity. 
On the other hand, the relation between 
Mayapan and the cities of the east coast 
of Yucatan is unmistakably close. Struc- 
tural techniques are almost identical, and 
parallels in external form are striking. 
Both groups emphasize the colonnaded 
palace with round columns and anthropo- 
morphic roof supports; and the simple 
unit shrines which form a large part of the 
structures in the two groups follow closely 
the same plans. The lack of carved stone 
facade decoration in the two areas paral- 
lels the restriction of the upper facade zone 
and simplification of the molding pattern. 
Other details such as walls surrounding the 
cities (Mayapan, Xelha, Tulum) imply 
further connection. It will be seen in 
Brainerd's report that available ceramic 
evidence equally strongly indicates that 
the so-called "Mexican period" remains at 



Chichen Itza form a horizon earlier than 
that of Mayapan and the east-coast cities. 

The above considerations suggest that 
the conventional division of peninsular 
culture into a "Maya period" and a "period 
of Mexican influence" by no means delin- 
eates the significant phases of its develop- 
ment. In the evolution of art, architecture, 
and ceramics, three quite different divi- 
sions seem clearly indicated by data now 
available : 

I. The earliest architecture in Yucatan 
is characterized by walls of large, crudely 
faced blocks, vaults of flat, entirely unpre- 
pared, corbeled slabs, and a complete ab- 
sence of carved stone facade decoration. 
Rough wall and vault faces were smoothed 
by a thick coat of stucco, which was also 
used in the execution of elaborate reliefs 
in the upper facade zones. This period of 
occupation is seen at Coba in the east, and 
is strongly represented in the Merida re- 
gion. Pollock and Shook have described 
contemporaneous and very similar archi- 
tecture at sites running from Maxcanu in 
the Puuc to Bakna in central-western Cam- 
peche. Brainerd characterizes associated 
ceramics by absence of evolved slateware, 
and affinities with Tzakol and perhaps 
Tepeu I in the Peten. The lower limits 
of this occupation are at least as early as 
the end of cycle 8. 

II. Sometime in the second half of cycle 
9, a drastic change took place in north- 
peninsular culture. From block-wall and 
slab-vault architecture, there was a sudden 
transition to rubble construction covered 
by only a thin veneer of finely cut stone. 
The simple external building form gives 
way to the complex but rigid patterns as- 
sociated with the architecture of the Puuc 
region, where the new forms may have de- 
veloped. The stucco facade was replaced 
by elaborate panels of carved stone mosaic. 
Along with this change in architecture 
came an equally striking development of 



DIVISION OF HISTORICAL RESEARCH 



263 



slatewares in pottery; the earlier wares 
disappear, and ceramic resemblances to 
the Peten are confined to tenuous similari- 
ties to Tepeu. This new culture does 
not seem to have been of foreign introduc- 
tion, for the new architectural and ceramic 
forms had their origins in the previous 
period. Early in cycle 10, continental Mexi- 
can influences appear at Chichen Itza, 
either coincidentally with or shortly after 
the abandonment of the Peten cities and 
those of the Puuc. During the so-called 
Mexican period at Chichen Itza, these in- 
fluences altered the superficial aspects of 
local culture, but notably failed to affect 
to any extent the fundamental architec- 
tural, sculptural, or ceramic techniques. 
Architectural innovations are seen in such 
features as replacement of the basal mold- 
ing by a battered lower zone, and the 
prominent use of serpent columns and 
stairway balustrades. But the basic con- 
struction of rubble buildings with a thin 
stone veneer remained unchanged until 
the abandonment of the site. New reli- 
gious motifs in sculpture accompany no 
great change in style. Finally, although 
imported trade pieces make their appear- 
ance in connection with changes in shape 
and design in local pottery, slatewares 
maintain undisputed dominance. 

III. The second great change in Yuca- 
tan culture took place about the middle 
of the fourteenth century, and was quite 
as radical as the first. Veneer was aban- 
doned, to be replaced by the use of uncut, 
rough blocks in a masonry more similar 
to that of modern native houses than to 
any earlier archaeological remains. Vaults 
are made of crude masonry, but are no 
more frequently used than the flat beam- 
and-mortar roof. A new temple form, the 
unit shrine, becomes numerically domi- 
nant. The colonnaded palace, which first 
appeared late in period II, takes on new 
form. Columns become universally round 



rather than square, and anthropomorphic 
roof supports are common. In sculpture, 
forms appear which bear little resemblance 
to previous artistic efforts of the Maya. In 
pottery, the slatewares vanish, to be 
replaced by what Vaillant called "red lac- 
quer wares" and (perhaps later) crude 
figurine incensarios. The new architectural 
forms persisted for the century and a half 
or two centuries until the Spanish con- 
quest. 

Guatemala: Kaminaljuyu 
E. M. Shook, A. L. Smith 

In 1936 and 1937 excavations were car- 
ried on at two mounds of the great archae- 
ological site of Kaminaljuyu in the out- 
skirts of Guatemala City (Year Books Nos. 
34-36). One of the mounds (A) was 
completely dissected. It proved to contain 
eight superimposed structures and to over- 
lie six pit tombs rich in pottery and jades. 
The body of the second mound (B) was 
not investigated, but three tombs were 
found below its frontal platform and a 
modern cut on one side indicated the 
probable presence of several structures 
built, as in Mound A, one above another. 
In the course of preparing the results of 
the above work for publication, it became 
obvious that more data were needed on 
several important points concerning archi- 
tectural and mortuary practices. It was 
therefore decided to excavate Mound B, a 
task undertaken by Mr. Shook and carried 
out from November 1941 through May 
1942. 

The mound before excavation was a con- 
ical hillock some 35 m. in diameter by 
7.5 m. high. A vertical slice had been cut, 
in recent times, from its western slope; 
and, some years before, a deep, wide trench 
had been run in from the southeast by 
treasure hunters. Mr. Shook's opening 
trenches were pushed inward from the 



264 



CARNEGIE INSTITUTION OF WASHINGTON 



north and south, these sides being chosen 
because the later structures in the mound 
were known to face west, and it had been 
learned, during the work on Mound A, 
that tombs and caches, stairways, and other 
important architectural features were to be 
found on the front and could more safely 
be reached by lateral than by frontal ap- 
proach. The south trench at once encoun- 
tered the basal step of a pyramidal sub- 
structure of puddled clay faced with a layer 
of lumps of pumice and coated with 
piedrin, an almost concrete -hard mixture 
of lime and small pebbles. The trench 
was pushed through this, revealing a sec- 
ond building of identical construction, 
which in turn was penetrated as far as a 
third building of pure adobe. There was 
thus disclosed a sequence corresponding 
to that found in Mound A, whose two 
outermost elements had pumice-and-clay 
heartings with piedrin finish, the third 
being of adobe. 

At this point it was felt that enough 
was known of the mound's make-up to 
permit the frontal features to be investi- 
gated. The basal step of the outermost 
building (Structure 5 in the final 
enumeration) was accordingly followed 
around the southwest corner and across 
the western face to its abutment against 
the remains of the frontal stairway. The 
basal step was also located on the north 
and followed around the northwest cor- 
ner to the stairway. The same method 
was employed in outlining Structure 4, 
and in laying bare the south side of the 
adobe pyramid, Structure 3. At the same 
time a third penetrating trench was run in 
from the east, encountering and passing 
through two more adobe structures, Nos. 
2 and 1. 

As to Structures 1 and 2, little was 
learned, for they were seen only in median 
section in the sides of the narrow pene- 
tration trench. They appeared to have 



been low pyramids, parts of which had 
been cut away in the course of building 
the later units of the complex. Structure 3, 
however, was relatively well preserved. It 
was an adobe pyramid with basal measure- 
ments of about 30 by 30 m., a broad adobe 
stairway with heavy balustrades mounting 
its western face. The upper part of the 
stairway had been destroyed by the pot- 
hunters' trench, but a small area of the 
summit platform remained. 

Structures 4 and 5, though inferior in 
construction to the corresponding units 
of Mound A, yielded the hoped-for infor- 
mation as to the pumice-and-piedrin type 
of building. It was learned that it had a 
low basal step, a lower sloping zone topped 
by a slab-supported cornice, and a more 
nearly vertical second zone divided by 
moldings into rectangular panels. At the 
front a stairway mounted to a jutting 
platform, on which there apparently was 
located a small shrine. A second flight, 
of which only traces of the lowermost steps 
remained, led upward, doubtless to a tem- 
ple on the summit platform. 

Two tombs were found: a small one 
south of the foot of Structure 5's stairway, 
and a very large one in front of the foot 
of the stairway of Structure 3. The small 
tomb contained the skeleton of an aged 
male, the bones of a child (probably a 
sacrifice), some jades, and a number of 
pottery vessels. The large grave was evi- 
dently that of an important personage, 
as it was more lavishly stocked with mor- 
tuary equipment than any of the other ten 
tombs so far opened at Kaminaljuyu. The 
principal occupant, seated cross-legged in 
the center of the tomb floor, had been liter- 
ally covered with ornaments of jade and 
shell; a necklace of 280 jade beads was 
about the neck. In front of the body was 
a pile of very fine pottery, many of the 
pieces coated with stucco and beautifully 
painted. The skeletons of three young 



DIVISION OF HISTORICAL RESEARCH 



265 



persons, evidently sacrificed at the time of 
their master's burial, lay toward the walls 
of the tomb. Near one of them was the 
finest single object recovered, a pyrite-in- 
crusted plaque whose slate backing bore an 
intricate carving, the central elements be- 
ing two small figures standing on either 
side of an altar, from which rises what ap- 
pears to be a conventional tree. 

Although the finds in this tomb were 
most spectacular, the most important re- 
sults of the Mound B excavation were the 
data recovered as to architecture and as to 
the succession of pottery types. Great num- 
bers of sherds were found in the fill. These 
were largely of the Esperanza phase, con- 
temporaneous with the erection of the 
structures, but among them were many 
fragments of Miraflores pottery. The lat- 
ter, representing the oldest ceramic hori- 
zon so far identified at Kaminaljuyu, had, 
of course, been scraped up with earth 
used for the fill of the various structures. 
After the mound had been abandoned 
as a place of worship and had fallen more 
or less into ruin, there accumulated on 
and about it a heavy stratum of occupa- 
tional debris containing pottery of two 
post-Esperanza phases which have been 
called Pamplona and Amatle. Although 
stratigraphic conditions were not clear, 
there is little doubt that Amatle is the 
older of the two. One component of 
the Amatle phase is plumbate ware, mostly 
in simple cylindrical forms. Similar plum- 
bate was found in 1940 by A. L. Smith at 
San Agustin Acasaguastlan on the Mo- 
tagua River, and more came to light in 
J. E. S. Thompson's excavations of the past 
season at El Baul on the Pacific coast 
plain. When these and other ceramic ma- 
terials from highlands and lowlands have 
been studied and compared, it seems prob- 
able that the chronological and commercial 
relations of several important ancient 
Guatemalan cultures will become clear. 



During the mapping of Kaminaljuyu 
in former years there had been noted at 
least nine constructions which, because of 
their elongated rectangular form, were 
surmised to be ball courts. In order to test 
this supposition, A. L. Smith, in 1941, ran 
a trench across the middle of one of the 
largest. The finding of two tenoned stone 
parrot heads, analogous to those of the 
Copan ball court, and of traces of sloping 
benches paralleling a playing alley settled 
the matter conclusively. 

During the past season further excava- 
tion was carried on here, and two smaller 
courts were investigated. The original 
1941 trench in the large court was re- 
opened and sunk to a depth of about 5.5 m. 
before sterile natural deposits were reached. 
Directly below the northern long wall, Mr. 
Smith exposed parts of two deeply buried 
earlier constructions. The upper one was 
of red-painted adobe, apparently with low 
vertical terraces. Its upper parts had been 
cut away in ancient times. An adobe floor, 
also painted red, extended outward from 
its base. Farther down was the southeast 
corner of a very well preserved building, 
prob