Department of Terrestrial Magnetism General Files, 1904-Present








Carnegie Institution of Washington

Department of Terrestrial Magnetism Archives

Washington, DC












Finding aid written by:

Jennifer Snyder and Ann Mulfort

May, 2005



Department of Terrestrial Magnetism General Files, 1904-Present




Table of Contents






Historical Note


Scope and Content Note


Folder Listing


Subject Terms





Department of Terrestrial Magnetism General Files, 1904-Present




Abstract: This collection contains the records of the Department of Terrestrial Magnetism (DTM) at the Carnegie Institution of Washington (CIW), established in 1904, continuing to the present. It contains directors’ correspondence; site and building plans; drawings of equipment and apparatus; photographs; news clippings; biographical files; diaries and reminiscences; visitor logs; and audio recordings. Notable studies conducted by DTM highlighted in the collection include geomagnetism, nuclear physics, the development of the proximity fuze, seismology, astronomy and geochemistry.

Extent: 50 linear feet; 29 file drawers, 14 map case folders.

Acquisition: The records have been in the possession of the Department of Terrestrial Magnetism (DTM) since their creation.


Access Restrictions: There are no access restrictions to this collection.

Copyright: Copyright is held by the Department of Terrestrial Magnetism, Carnegie Institution of Washington. For permission to reproduce or publish please contact the archivist at the Department of Terrestrial Magnetism.


Preferred Citation: Department of Terrestrial Magnetism General Files, 1904-Present, Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, D.C.


Processing: This collection was processed by Jennifer Snyder and Ann Mulfort in May 2005 through the generous support of the National Historical Publications and Records Commission.


During the processing of this collection, the archivists discovered that previous managers of the materials weeded the files of Series One: Chronological Files through 1965. Since no subsequent weeding occurred, later files were found to contain a greater volume of nonessential correspondence. To make the collection more useable, the archivists consolidated all of the purchase orders into one file for each subseries from 1963 on. Beginning with the 1965 files, correspondence lacking a specific folder title was consolidated in folders for each letter of the alphabet (e.g.: A: Miscellaneous).



Historical Note

The Department of Terrestrial Magnetism was established in 1904 by Louis Agricola Bauer, who became the Department’s first director. The original mission of the Department was to measure the earth’s magnetic field and its variations. Magnetic survey stations and observatories were established across the globe, and ocean survey expeditions began. Two ships were commissioned for these seafaring journeys—the Galilee, in 1905 and the Carnegie (named in honor of the Institution’s founder), a completely non-magnetic ship, which took over the research, in 1909.


In the 1920s, the Department’s research focus began to broaden. Merle Tuve and Gregory Breit, two DTM physicists, began working on verifying the existence of the earth’s ionosphere in 1925. During the 1930s and 1940s the laboratory “became a world-class center for the study of nuclear physics, which made fundamental discoveries about atomic forces.” (Trefil 54) In 1939 the uranium atom was split for the first time in the U.S. on DTM’s campus in the Atomic Physics Observatory. In 1940, work began on the proximity fuze which would change the face of warfare for the United States. Later, fuze activities would move to the Johns Hopkins Applied Physics Laboratory, which was headed by Tuve. “After the war, departmental scientists branched off into new fields, including isotope geology, seismology, astronomy, and biophysics. The diverse efforts resulted in discoveries regarding the structure of the Earth, age-dating techniques, the properties of genomes, and the existence of dark matter.” (Trefil 54)


Please see appended timeline for achievements at the Department.


A chronology of the directorships of the department is as follows:

Š      Louis A Bauer (1904-1929)

Š      John A. Fleming, Acting Director (1929-1934); Director (1935-1946)

Š      Merle A. Tuve (1946-1967)

Š      Ellis T. Bolton (1967-1974)

Š      George W. Wetherill (1974-1991)

Š      Louis Brown, Acting Director (1991-1992)

Š      Sean C. Solomon (1992- )



Scope and Content

This collection consists of records from over 100 years of scientific studies at DTM. The materials include correspondence, photographs, news clippings, equipment designs, blueprints, maps, site plans, diaries, visitor logs, and audio recordings. This collection documents the evolution of a program whose initial charge was to study the magnetic and electric condition of the earth and its atmosphere. Other programs of research, conducted for varying periods of time (some still active at present) include: radio and optical astronomy; nuclear physics; seismology; biophysics; ionosphere and cosmic ray studies; isotope geochemistry and cosmochemistry; and astrobiology.




This collection is arranged in two series and maintains the organization developed by the original managers of these materials. The files are arranged alphabetically within the subseries of Series 1 and Series 2.


Series 1: Chronological Files, 1910-1985

Subseries 1: To 1934

Subseries 2: 1935-1948

Subseries 3: 1949-1952

Subseries 4: 1953-1954

Subseries 5: 1955-1956

Subseries 6: 1957-1958

Subseries 7: 1959-1960

Subseries 8: 1961-1962

Subseries 9: 1963-1964

Subseries 10: 1965-1966

Subseries 11: 1967-1968

Subseries 12: 1969-1970

Subseries 13: 1971-1972

Subseries 14: 1973-1974

Subseries 15: 1975-1980

Series 2: Archives Files, 1904-Present



Series 1: Chronological Files, 1910-1985

This inactive series contains fifteen subseries organized by date. The materials include correspondence, photographs, maps, equipment designs, news clippings, and site plans derived chiefly from each director’s office correspondence. Department communication with other research organizations include the Lowell Observatory, Mount Wilson Observatory, the National Institutes of Health (NIH), the National Science Foundation (NSF), the National Academy of Sciences (NAS), and the National Bureau of Standards. DTM’s involvement in defense contracts throughout World War II is contained in the files of the U.S. Navy. The development of image tubes for optical telescopes is included in this series. All of these materials demonstrate DTM’s cooperation with various organizations. Because the work in many fields of the department took place over several years, some topics can be found in multiple subseries.


Although the International Geophysical Year took place 1957-1958, details of DTM’s preparation for and participation in this endeavor can be found in earlier years throughout this series. Key correspondents in this series include L. Thomas Aldrich, James P. Ault, Dean B. Cowie, Odd Dahl, Scott E. Forbush, Richard B. Roberts, and Vera C. Rubin.


Series 2: Archives Files, 1904-Present

This active series contains correspondence, photographs, maps, blueprints, and news clippings. These materials were maintained separately from the chronological files for permanent retention of topics of historical significance to the department. Materials continue to be added to this series.


Of interest in this series is the photographic collection of the Carnegie VII cruise taken by Floyd Melville Soule, the diary of the Trans-Saharan Expedition (1912-1913) by Darius W. Berky, the autobiographical materials by Richard B. Roberts, and reminiscences by former staff members and crew members serving on the department’s research vessels. Extensive documentation concerning the department’s operation of geophysical observatories at Huancayo, Peru and Watheroo, Australia is also present.



Folder Listing

Please see the DTM General Files database for a complete folder listing. There is also a printout of the folder titles in the collection’s control file. Please inquire with the archivist for access to the printed list.


Subject Terms



Geophysical observatories



Image converters

International Geophysical Year, 1957-1958

Nuclear physics


Radio astronomy

Scientific expeditions



Corporate Names:

Carnegie Institution of Washington. Dept. of Terrestrial Magnetism

Carnegie (Ship)

Galilee (Ship)

Johns Hopkins University. Applied Physics Laboratory

Lowell Observatory

Mount Wilson Observatory

National Institutes of Health (U.S.)

National Science Foundation (U.S.)

United States. National Academy of Sciences

United States. National Bureau of Standards

United States. Navy


Personal Names:

Aldrich, Lyman Thomas, 1917-

Ault, J. P. (James Percy), 1881-1929

Bauer, L. A. (Louis Agricola), 1865-1932

Berky, Darius W.

Bolton, Ellis T.

Cowie, Dean B.

Dahl, Odd, 1898-1994

Fleming, J. A. (John Adam), 1877-1956

Forbush, Scott E., 1904-

Roberts, Richard B. (Richard Brooke), 1910-1980

Rubin, Vera C., 1928-

Soule, Floyd M. (Floyd Melville), 1901-

Tuve, Merle Antony, 1901-1982      

Wetherill, George W.



Administrative records








Plans (drawings)


Site plans

Visitors’ books




Trefil, James and Margaret Hindle Hazen. Good Seeing: A Century of Science at the Carnegie Institution of Washington, 1902-2002. Washington, D.C.: Joseph Henry Press, 2002.



Other Sources

Brown, Louis. The Department of Terrestrial Magnetism. Vol. 2 of Centennial History of the Carnegie Institution of Washington. 5 vols. Cambridge: Cambridge University Press, 2004.

Celebrating 100 Years of Discovery at the Department of Terrestrial Magnetism, 1904-2004. Washington, D.C.: DTM, 2004.

Carnegie Institution: Department of Terrestrial Magnetism. Washington, D.C.: CIW, 2003.

Timeline of Selected Events and Achievements at the Department of Terrestrial Magnetism

Compiled in 2004 for the DTM Centennial


1902 - Louis A. Bauer submits proposal to establish an “international magnetic bureau” to coordinate research and conduct surveys in unexplored regions

1903 - Carnegie Board of Trustees approve proposal and allocate $20,000 for the first year’s operations; Bauer named Director

1904 - In conformity with the authority conveyed in the Secretary’s letter of March 29, 1904, the work of the [Department of International Research in Terrestrial Magnetism] was begun on April 1, 1904, and since then has been steadily prosecuted.
L. A. Bauer in the 1904 CIW Year Book

1905 - First land magnetic expeditions dispatched

1905 - Magnetic survey of the Pacific begun using the chartered vessel Galilee

1907 - Name shortened to “Department of Terrestrial Magnetism”

1909 - Launch of non-magnetic yacht Carnegie

1911-1913 - Participation in Australasian Antarctic Expedition

1913 - Experimental studies of magnetism and atmospheric electricity begin

1914 - DTM moves to Broad Branch Road site

1915-1916 - Carnegie circumnavigates Antarctica in a single season

1917-1918 - Staff conduct research on magnetic compasses for aircraft, anti-submarine devices, and magnetic mines during WWI

1918-1925 - Collaboration with Roald Amundsen on Maud Expedition

1919 - Watheroo Magnetic Observatory established by DTM in Western Australia

1920 - Experiment Building constructed

1921 - Carnegie decommissioned at conclusion of Cruise VI

1921-1924 - Temporary “igloo” observatories built on Baffin Island and Greenland during MacMillan Bowdoin expeditions

1922 - Huancayo Magnetic Observatory established in Peru

1925 - Height of the ionosphere measured using pulsed radio signals

1927 - Carnegie recommissioned and refitted for comprehensive oceanographic research on Cruise VII

1928 - High-voltage studies begin, using Tesla Coil as particle accelerator

1929 - Carnegie destroyed by explosion and fire in Apia, Samoa, November 29; Captain Ault killed

1930 - John A. Fleming becomes Acting Director; named Director in 1935

1930 - DTM magnetic instruments flown on board the airship Graf Zeppelin

1930 - Studies of radiation effects on lab animals and establishment of useful standards for radiation exposure

1931 - DTM participates in Nautilus Polar Expedition, first attempt to travel by submarine beneath Arctic ice-pack

1932 - Formation of “Committee on Coordination of Cosmic Ray Investigations,” centralized at DTM

1932-1933 - International Polar Year stations set up at Fairbanks and Point Barrow, Alaska

1932 - Atomic physics group abandons use of Tesla Coil, turns to Van de Graaff generators

1933 - Experiment Building extension built to house 2-meter Van de Graaff

1934 - Systematic monitoring of cosmic-rays begins, using Compton-Bennett meters

1935 - First of ten Washington Conferences on Theoretical Physics, co-sponsored by George Washington University and DTM

1935 - Studies of proton-proton scattering lead to understanding of strong nuclear force

1935 - Multi-frequency automatic ionospheric sounder built, becomes international standard

1935 - Manned balloon Explorer II carries DTM electrical conductivity experiments into stratosphere

1937 - Appointment of first DTM postdoctoral fellow, physicist Richard B. Roberts

1937 - Discovery of Forbush effect (cosmic-ray intensity decrease during magnetic storms)

1938 - Atomic Physics Observatory (APO), a 3 million-volt, pressure- tank, Van de Graaff accelerator, becomes operational

1939 - Uranium atom split at APO on January 28 with Bohr and Fermi present, following 5th Washington Conference on Theoretical Physics

1939 - Delayed neutron from uranium fission discovered

1939 - Tuve named to President Roosevelt’s Uranium Committee

1940 - Proximity fuze development begins

1940 - Construction of 60-inch cyclotron starts

1940 - Research Associates Sydney Chapman and Julius Bartels publish classic treatise Geomagnetism

1941 - College Observatory (forerunner of today’s University of Alaska Geophysical Institute) established in Fairbanks as joint DTM-University of Alaska facility

1942 - Fuze research and development transferred to Applied Physics Laboratory; 22 million fuzes manufactured by War’s end

1943-1944 - Global network of ionosphere stations set up for wartime radio propagation studies

1943 - Cyclotron produces first beam, New Year’s Eve; radioisotopes produced for biomedical research

1946 - Merle A. Tuve succeeds Fleming as Director and initiates modern DTM research directions in seismology, geochronology, and radio astronomy; geomagnetism research terminated

With the completion of many volumes of survey and observatory results, and the transfer of the observatories to other agencies, the Department during this report year has begun to function effectively as a physics department with special research interests in geophysics and in laboratory physics....A deliberate aim to work as physicists, in reasonably fresh areas, on significant problems, however difficult and on problems directed toward philosophical goals without reference to possible applications, is the general policy adopted for guiding the selection and emphasis of the work carried forward. -Merle A. Tuve, Year Book #47 (1947-1948)

1946 - Expansion of rock magnetism studies

1947 - Derwood (Maryland) Field Station established for ionospheric, cosmic-ray, and (later) radio astronomy work

1947 - Lunch Club established

1947-1948 - “Project Thunderstorm” measures air conductivity and potential gradient from B-29 bombers

1948 - Explosion seismology experiments begin, using war-surplus explosives; first shots in New Mexico and Chesapeake Bay region

1949 - Biophysics group begins studies of biosynthesis in E. coli bacteria

1950 - Mass spectrometry applied to geochronology in collaboration with Geophysical Lab

1951 - DTM-GL seismic expedition to Canadian Shield

1952 - Coulomb excitation opens new avenues for nuclear structure studies

1952 - Installation of DTM’s first radio telescope, a 7.5-meter German radar dish, for studies of galactic hydrogen

1953 - Application of ion-exchange resins to chemical separation in geochronology

1954 - “Committee on Electronic Image Converters for Telescopes” begins work

1955 - Discovery of radio emissions from Jupiter

1956 - “Concordia” method makes U-Pb age determination accurate

1957 - Seismic expedition to Andes during International Geophysical Year, with shots fired in open-pit copper mines in Peru and Chile; first use of NSF funds for DTM field work

1958 - Paleomagnetism studies terminate

1959 - Control of Journal of Geophysical Research, edited and published at DTM since 1904, transferred to American Geophysical Union

1960 - 18-meter radio astronomy dish installed at Derwood

1960-1961 - Cooperative network of seismic stations established in Peru, Bolivia, and


1961 - Polarized ion source installed in APO

1962 - 2-meter Van de Graaff donated to Smithsonian Institution

1963 - Agar column technique devised, transforming microbiology

1963 - Lake Superior seismic experiment involves 14 groups from 5 nations

1963 - “Carnegie Earthquake Seminar” brings South American researchers to DTM

1963-1964 - Recognition of long-lived isotope systems as tracers of geological processes

1964-1965 - 30-meter radio astronomy dishes erected at Derwood and La Plata, Argentina

1964 - Installation of “Carnegie image tubes” begins at observatories worldwide

1965 - East Coast Onshore-Offshore Experiment probes Appalachian crustal structure

1966 - Ellis T. Bolton becomes fourth Director; L. Thomas Aldrich named Associate Director

1966 - First non-human computer, an IBM 1130, installed at DTM

1966 - Broad-band seismograph developed

1968 - Sacks-Evertson borehole strainmeters developed

1968 - New “geochemistry” designation reflects geochronology group’s growing interest in isotopes as tracers

1971 - First strainmeter installed off DTM campus, at Matsushiro, Japan

1971 - Geochemists introduce computer control of mass spectrometers

1971 - First plate tectonic model for formation and evolution of the Andes

1972 - Carnegie sponsors Airlie House Conference on “Plate Tectonics and the Evolution of Continents’’

1973 - Carnegie sponsors Airlie House Conference on “Geochemical Transport and Kinetics,” marking push to understanding diffusion and its role in geochemistry

1973 - Project NariĖo, a multi-national explosion seismic project, confirms complexity of Andean crustal structure

1974 - George W. Wetherill becomes DTM’s fifth Director, brings research direction in theoretical Solar System evolution and cosmochemistry to DTM

1974-1976 - Biophysics group phased out

1975 - Operation of Van de Graaff accelerator and radio telescopes terminated

1975 - Rb-Sr mantle isochrons show continental mantle is both different and old

1976 - DTM Dynamos meet Geophysical Lab (GL) Pistons on the soccer field; Dynamos prevail 4-0

1977 - Geochemistry proposed as a way to constrain mantle circulation

1978 - Discovery of slow/silent earthquakes enabled by array of strainmeters in Japan

1978 - Evidence of dark matter found from galaxy rotation curves

1979 - Identification of role of subducted oceanic crust in mantle evolution

1979 - Strainmeters installed in Iceland

1983 - Purchase of commercial multicollector mass spectrometer

1984 - Carnegie fosters organization of PASSCAL seismic consortium

1984 - Carnegie becomes founding member of Incorporated Research Institutions for Seismology (IRIS)

1985 - Observations of very young stars and star-forming regions begin

1986 - Beryllium-10 studies demonstrate sediment involvement in subduction

1986-1987 - Mass spectrometer altered for laser ionization; research using Re-Os system initiated

1988 - First results on fossil anisotropy in the mantle

1988 - Penetrative convection proposed to explain both geochemistry and geophysics of mantle

1989 - Ground broken for new Research Building on January 30

1989 - First deployment of DTM portable seismic array in “APT89 Experiment,” 1500-km transect across US and Canada

1990 - Geophysical Laboratory moves to Broad Branch Road campus

1991 - Wetherill retires; Louis Brown named Acting Director

1992 - Sean C. Solomon becomes DTM’s sixth Director

1992-1999 - Brazilian Lithosphere Seismic Project employs 20+ portable broadband stations in joint DTM-University of Sčo Paulo study

1993 - First strainmeter study of volcanic eruptive processes

1994-2001 - Collaboration in Hubble Space Telescope key project on Cepheid variables refines distance scale of the universe

1995-1996 - Ion Microprobe Laboratory built in former cyclotron vault; cosmochemistry strengthened in research program

1996 - “Mud Cup I” rekindles DTM-GL soccer rivalry

1996 - Research effort on planetary volatiles and interplanetary and interstellar grains begins with ion probe

1997 - Hubble Space Telescope photos of “antennae” galaxies bring national attention to work on merging galaxies

1997 - Automation of ion probe to hunt for isotopically anomalous interstellar grains

1997-1998 - Acquisition of inductively-coupled plasma mass spectrometers

1997 - Undergraduate summer intern program begins in collaboration with GL

1997-2002 - Kaapvaal Craton Project brings seismo-logists and geochemists together in multinational, multidisciplinary study of southern Africa’s cratons

1998 - Carnegie becomes founding member of NASA Astrobiology Institute

1998 - Identification of extra-Solar System oxide grains from supernova

1998 - Feasibility of using Re-Os on sulfide inclusions in diamonds demonstrated

1999 - DTM enters search for extrasolar planets, complementing ongoing theoretical work in planet formation

1999 - Two borehole geophysical observatories installed in ocean bottom off Tohoku, Japan

1999 - First transit of an extrasolar planet detected around HD 209458

2000 - Strainmeters predict eruption at Hekla

2001-2003 - Astronomy group changes its focus to planets and the Solar System

2002 - First volcano-specific strainmeter deployment captures Montserrat dome collapse

2004 - Launch of MESSENGER spacecraft to Mercury on August 3, a joint Carnegie-APL-NASA mission

2004 - Discovery of Neptune-mass exoplanets