The Rise of Robert Millikan: Portrait of a Life in American Science
Night Thoughts of a Classical Physicist
According to their authors, both books under review set out to portray an epoch in physics through the medium of a biography. The period dealt with is almost the same, the late nineteenth and early twentieth centuries, though one story extends into the Fifties, whereas the other ends effectively in 1918. One is about American physics, the other about German physics and physicists. But the main difference is that one author has chosen a real physicist, in fact one who contributed to the development of modern physics, whereas the other book is about an imaginary person.
Robert Kargon’s The Rise of Robert Millikan is a workmanlike effort. Millikan, born in 1868, was old enough to be educated during the reign of “classical” physics and influenced strongly by the belief of his teachers, including the famous Albert Michelson, that the aim of physics was to measure known quantities with greater and greater precision. He lived through the great revolutions in physics started by the discoveries of the electron, of X-rays, and of radioactivity, and leading to the theory of relativity and the quantum theory.
At the age of twenty-seven, when he had started on research with some minor, but sound, papers, he made a trip to Europe, and here met the beginnings of the “new” physics. This was not an accident, because then the center of physics was in Europe, and discoveries were mostly made there. He also had the opportunity of working with Walther Nernst, and published a paper based on it. But it was not until 1907 that he turned to the problem which would bring him his main success. The reason was in part that he had, in his position at the University of Chicago, very heavy teaching duties, which he took seriously and which led him to write some successful textbooks. But more important, he could not decide on a topic on which major progress was possible. Some of his experiments were successful, but not exciting, others led nowhere. The result was a considerable lack of confidence in himself and his ability.
But in 1907 he decided to try to measure the charge of the electron, discovered by J.J. Thomson ten years before. The electron charge, one of the most fundamental constants of physics, was then known only in a very rough approximation, and efforts to improve the accuracy of the measurement had not succeeded. Millikan experimented with the method used by others, namely to produce a cloud of water droplets in an electric field, and to watch the slowest-moving part of this, which presumably consisted of droplets carrying only one unit of charge. He realized that the only way of doing better was to observe individual droplets, but these evaporated too quickly to be kept under observation for a long enough time. He then hit on the solution of using drops of oil instead of water. There are more steps to the experiment than can be described here, but the result was a very …