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Robert Andrews Millikan Papers

Identifier: 10132-MS

Scope and Content of Collection

The materials pertaining to Robert A. Millikan at the California Institute of Technology are extensive. In addition to the collected papers with which this guide is primarily concerned, there are in the Institute Archives the medals, citations, diplomas, academic regalia and other awards given to Millikan in recognition of his scientific, scholarly, and civic achievements. A small segment of Millikan's private library, about two hundred volumes, is housed in the Archives. There are also hundreds of photographs of Millikan, his family, colleagues, and apparatus. A small number of sound recordings of talks given by Millikan is available.


  • 1821–1953


Language of Materials



The collection is open for research. Researchers must apply in writing for access.

Publication Rights

Copyright may not have been assigned to the California Institute of Technology Archives. All requests for permission to publish or quote from manuscripts must be submitted in writing to the Head of the Archives. Permission for publication is given on behalf of the California Institute of Technology Archives as the owner of the physical items and is not intended to include or imply permission of the copyright holder, which must also be obtained by the reader.


Robert Andrews Millikan (1868-1953) is best known as an experimental physicist. The oil drop method developed by Millikan enabled him to establish the long accepted value for e, the elementary unit of electrical charge. His pioneering investigations into the photoelectric effect gave important support to the quantum theory of light. For these achievements he was awarded the Nobel Prize in physics in 1923. He was also widely known as the author, with Henry Gordon Gale, of a series of textbooks that were the mainstay of physics courses in the first half of the twentieth century. Several generations of Americans literally learned their physics from Millikan.

For twenty-five years (1921-1945), Millikan guided the growth and development of the California Institute of Technology, choosing for himself the title, Chief of the Executive Council. Millikan's vision for Caltech was shared by his two close associates, the chemist Arthur A. Noyes and the astronomer George Ellery Hale. It was Hale and Noyes who had played a determining role in inducing Millikan to come west in 1921. Together, they promoted the development of Caltech, the magnificent Henry E. Huntington Library and Art Gallery, the 200-inch Hale telescope, and a variety of other highly significant projects that helped to make Pasadena an important intellectual and scientific center. Caltech is in a very real sense a monument to these three men.

Before coming to Caltech, Millikan had already distinguished himself as an administrator and promoter of science. He became president of the American Physical Society in 1916 and in the same year was appointed to a committee formed by the National Academy of Sciences to organize the National Research Council, an organization of scientists created to advise and assist the federal government in the mobilization of scientific resources during World War I. As Executive Officer and Director of Research of the National Research Council (he was also commissioned as a major in the Army Signal Corps) Millikan supervised important developments in the areas of submarine detection and chemical warfare. This post also involved him in critical deliberations that were to influence national policies toward science for many years.

The National Research Council became a permanent body at the end of the war, and Millikan remained prominent in its affairs throughout the remainder of his life. One of the accomplishments of which he was most proud was the creation, at his suggestion, of the National Research Council Fellowships. These fellowships made an enormous contribution to the vitality and progress of American science in the postwar decades.

Despite administrative duties, Millikan remained an active scientist. He was intimately involved in the day-to-day work of the Norman Bridge Laboratory at Caltech; under his leadership, it quickly became a mecca for physicists. In conjunction with his students and assistants, dozens of whom later became important physicists, he made significant contributions to the study of "hot spark" spectra and cold emission (today known as field emission) of metals. Investigations into the nature and properties of cosmic rays consumed much of his attention. He made frequent field trips, often to nearly inaccessible places, to measure radiation variations over the surface of the planet. His work in this area involved him in a rancorous scientific dispute with Arthur Holly Compton, also a pioneering investigator of cosmic rays, over the source and character of such radiation.

Unlike many of his countrymen in the years after World War I, Millikan was a confirmed internationalist. He served as a member of the League of Nations Committee on Intellectual Cooperation and the International Research Council. With the advent of the Second World War in Europe, Millikan believed that the United States could not, and perhaps should not, avoid involvement. Under his prodding, Caltech geared itself to wartime pursuits. The aircraft industry of Southern California, already indebted for its primacy to Caltech aerodynamicist Theodore von Kármán, relied heavily upon the Institute for research and development of a broad range of critically-needed devices. A program to develop and manufacture armed rockets was begun, leading to the creation of the Jet Propulsion Laboratory.

In 1945, at the end of the war, Millikan officially retired but continued to be active in the affairs of Caltech as well as to pursue his scientific and civic interests. His career had brought him into contact with a broad spectrum of the leading scientists, intellectuals, business people, and political figures of his era. Gregarious and charming, Millikan had made many friends. Though advancing age made it necessary to reduce his burden of commitments, he continued to participate in fund raising drives for Caltech, kept an ambitious schedule of public speaking, and still served on the boards or in advisory positions for several institutions of which he had long been a mainstay.

Millikan's life had been long and productive. Born in Illinois in 1868 into a pioneering family and the son of a Congregational preacher, Millikan never forgot his ancestral heritage. Nor did worldly success cause him to stray from his father's religion; over the years he devoted a considerable amount of energy to the reconciliation of Christianity, morals and science. He graduated from Oberlin College in 1891, took a master's degree there in 1893, received his doctorate from Columbia University in 1895, and then went to Germany for several months of continued studies. In 1896 he joined the faculty of the University of Chicago, where he remained, with the exception of the war years spent in Washington, D.C., until he moved to Pasadena.

Having overcome his prospective father-in-law's stipulation that he first obtain a larger salary from the University of Chicago, Millikan was able to marry Greta Irvin Blanchard in 1902. They honeymooned in Europe; their frequent, detailed letters written during this and subsequent journeys were carefully preserved. The couple had three sons, two of whom they survived. Clark B. became an aeronautical engineer and joined the faculty of Caltech. Max F. was a political scientist at the Massachusetts Institute of Technology for many years. Glenn A. was killed in his early twenties in a mountain climbing accident. Family relationships were close, and when separated, the Millikans corresponded regularly. The letters Robert and Greta exchanged whenever they were apart were intimate and affectionate throughout their years. Greta died in late 1953. Robert followed within weeks on December 19.

Selected Bibliography. The most widely available as well as the fullest account in print of Millikan's life and works is his Autobiography (New York: Prentice-Hall, Inc., 1950). It is informative but not always reliable. Of particular value are his accounts of his early years, his work while at Chicago, and his national service during World War I.

Lee A. DuBridge and Paul S. Epstein, "Robert Andrews Millikan, 1868-1953: A Biographical Memoir," National Academy of Sciences Biographical Memoirs, XXXIII (New York: Columbia University Press, 1959), pp. 240-282, provides a biographical sketch and an appreciation of Millikan's scientific and administrative accomplishments. Appended to the memoir is a complete bibliography of Millikan's published writings, approximately three hundred of which appeared between 1895 and 1950.

Another valuable biographical memoir, emphasizing Millikan's scientific endeavors, is Daniel J. Kevles, "Robert A. Millikan," in the Dictionary of Scientific Biography, IX (1974), pp. 395-400. Kevles has also authored "Millikan: Spokesman for Science in the Twenties," Engineering and Science XXXII (April 1969), pp. 17-22.


50 linear feet


The core of the Robert A. Millikan Collection at the California Institute of Technology consists of the official papers generated by Millikan during the twenty-five years that he was the executive officer at the Institute. The bulk of the papers consist of correspondence, lecture notes, and other materials dealing with scientific and academic matters.

Organization of Collection

Organized into the following series: I. Millikan Scientific Notes; II. Millikan Correspondence: World War I Material; III. Millikan Correspondence re Organizations and Committees; IV. Millikan Correspondence re Caltech; V. Millikan Personal Correspondence; VI. Millikan Family Correspondence; VII. Millikan Speeches and Articles; VIII. Millikan Autobiographical Writings; IX. Millikan Family Documents and Memorabilia; X. Printed Matter.

For scholars pursuing topics related to Millikan's professional activities, Boxes 1 through 42 of the Millikan Collection will hold the greatest interest as they contain the bulk of correspondence and other papers dealing with scientific and academic matters. His lecture notes, found in Boxes 1 and 2, offer glimpses of Millikan's classroom technique as well as an insight into the state of physics at the turn of the century. Of similar interest is the assortment of notebooks in Boxes 3 and 4 in which Millikan recorded data from his scientific experiments. Millikan played a significant role in the mobilization of science for national defense during World War I, much of which is documented by materials in Box 5.

However, the preponderance of the material in this part of the collection deals with the period between 1921 when Millikan came to Caltech and 1953 when he died. Millikan's Chicago years are not well represented. (Some material is scattered through several collections at the University of Chicago, but no systematic collection of his early papers is extant.) Millikan was in actuality, if not in title, executive head of Caltech until his retirement in 1945, and his correspondence reflects an administrator's concerns. He was determined to put Caltech in the front ranks of scientific research and teaching institutions; his papers illuminate the methods through which that goal was realized. There is little in the collection pertaining directly to his own scientific work during these years. He remained active in the affairs of the National Academy of Sciences, the National Research Council, and similar organizations devoted to the promotion of scientific research; materials relating to these activities will be found in abundance. He was for many years a trustee of the Henry Huntington Library and Art Gallery in nearby San Marino. Much of his activity in that capacity is documented in the collection.

Millikan was an avid correspondent. Among his most frequent correspondents were fellow scientists and administrators, such as Frank B. Jewett, Karl T. Compton, Paul Brockett, Albert Barrows, and Gano Dunn; and Southern California business figures, such as Harry Chandler, Henry M. Robinson, Arthur H. Fleming and John A. Fleming. Herbert Hoover and other political figures appear often in the collection. Millikan worked closely with astronomer George Ellery Hale and aerodynamicist Theodore von Kármán; their papers (also housed in the Institute Archives) contain a great many more Millikan letters. The critical role played by Caltech during World War II is shown in his extensive correspondence with Henry H. ("Hap") Arnold and Vannevar Bush.

The most intensively indexed part of the collection is that portion dealing with Millikan's professional affairs. The remainder, primarily Boxes 47 through 99, is material of a more personal or family nature. Its character is less complex, obviating the need for detailed indexing. Here one finds the voluminous correspondence that passed between Millikan and his wife, Greta, during the frequent periods when they were apart. Greta's correspondence with other family members and friends is also found in these boxes. Together, these letters provide a rich social commentary, not only on the private lives of the Millikan family, but also on contemporary events, and in Greta's case, on the roles played by the wife of a famous scientist and administrator.

Other family material in the collection includes letters and writings by the couple's three sons, Clark, Glenn, and Max, as well as members of each of their families. (The Institute Archives also has the papers of Clark Millikan, who was a professor of aeronautics at Caltech from 1928-1966). This portion of the collection includes a variety of scrap-books, photo albums, newspaper clippings, legal papers, diaries, notebooks, manuscript drafts, and reprints which defy comprehensive description.

Acquisition Information

Shortly after Millikan's death, the family presented to the Institute his correspondence, personal papers, and items from his library. Four filing drawers of Millikan memorabilia were subsequently deposited in the Library in 1959 by his son, Clark.

Following the establishment of a permanent archival program at the Institute in 1968, Archivist Judith R. Goodstein supplemented the collection with material from other sources, including additional gifts of the Millikan family and facsimiles of Millikan correspondence found in such repositories as Cambridge University Library and Algemeen Rijksarchief in The Hague.

Alternate Formats of this Collection

This collection is also available in microfilm.

Processing History

In 1966 Daniel J. Kevles, historian of science at Caltech, began the collation and preliminary organization of the collection. In this he had the advice and encouragement of Charles Weiner, at that time Director of the Center for History of Physics at the American Institute of Physics. Lee A. DuBridge, President of Caltech, made available funds and space for the project. Kevles and his assistant, Rowena Danziger, produced an inventory list that was long the only guide to the collection.

Albert F. Gunns, historian at California State University, Long Beach, undertook the systematic organizing, cataloging, and indexing of the collection in 1971, with the help of Carol Finerman, Jackie Kuhl, and Ruth Gordon. Funding for the publication of the print guide in 1975 was provided by the Center for History of Physics at the American Institute of Physics. A second guide to the microfilm edition of the papers was published by Gunns and Judith R. Goodstein in 1977.
Guide to the Papers of Robert Andrews Millikan, 1821–1953
Albert F. Gunns and Judith R. Goodstein
Description rules
Describing Archives: A Content Standard
Language of description
Script of description
Code for undetermined script
Edition statement
Francisco J. Medina. Derived from XML/EAD encoded file by the Center for History of Physics, American Institute of Physics as part of a collaborative project (1999) supported by a grant from the National Endowment for the Humanities.

Repository Details

Part of the California Institute of Technology Archives and Special Collections Repository

1200 East California Blvd.
MC B215-74
Pasadena California 91125 United States of America
(626) 395-2704