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Quantum Squabbles

The Rise of Robert Millikan: Portrait of a Life in American Science

by Robert H. Kargon
Cornell University Press,, 205 pp., $22.50

Night Thoughts of a Classical Physicist

by Russell McCormmach
Harvard University Press,, 217 pp., $15.00

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 accurate determination of the charge. This experiment was one of the two for which he was to receive the Nobel Prize, the second American physicist to be so honored.

The other had to do with the photoelectric effect, and here the story is more complicated. It was known that light falling on a metal surface can eject electrons from it. It was found that the speed of the electrons did not depend on the intensity of the light, but on its color. Einstein explained this by making use of Planck’s idea of light quanta. If light consists of individual quanta, each carrying an amount of energy dependent on the color of the light, then the result is understandable. But the experiments were not accurate, and therefore Einstein’s theory was in some doubt.

Millikan could not accept this explanation. If light was made up of little particles, one would have to give up regarding light as waves, and there was plenty of evidence for the wave nature of light. In fact, the apparent contradiction between the wave and the particle pictures was one of the deep mysteries that got cleared up only by the new quantum mechanics in the late Twenties. So Millikan set out to disprove Einstein’s explanation; but he was a good experimenter, and his very accurate measurements confirmed the explanation exactly. He now accepted the Einstein formula, but still maintained that the underlying theory could not be right. In any case, he had obtained a very accurate determination of Planck’s constant, which enters into Einstein’s formula, since the energy of each light quantum depends on it.

This, too, was the basis of his Nobel award. At first, although he had verified the Einstein formula, he could not believe the theory behind it. But, Kargon tells us, he claimed in his autobiography that he immediately saw that the only possible interpretation of the data was provided by Einstein’s theory. It seems he did not like having been wrong, and conveniently forgot his incorrect pronouncements.

A similar situation arose again much later in connection with cosmic radiation. The dust cover of the book describes Millikan as the explorer of cosmic radiation, but the honor of discovering it belongs to the German Victor Hess. What Millikan did was important enough, for it was at first not clear that this was a radiation from outer space, and that it did not originate in some radioactive contamination of the atmosphere. Millikan studied carefully the variation with altitude, and proved that the radiation did indeed come from outer space. He gave it the name “cosmic radiation.”

He believed, as did most people initially, that this was electromagnetic radiation, like X-rays or gamma rays, and from its penetrating power, which for such radiation would have provided information about its energy, he convinced himself that it was radiation emitted in the process of building up atoms, a possibility in which he had always been greatly interested. However, in 1927 the Dutch physicist Jakob Clay found that the cosmic rays depended strongly on latitude, and this clearly had to be due to the magnetic field of the earth, which can deflect charged particles but not electromagnetic radiation. Thus the rays consisted of charged particles.

Millikan did not want to accept this, and set out to disprove the latitude effect. He sent one of his collaborators on an expedition to test it, and at first the results seemed to be negative. He therefore insisted in a public debate with Arthur Compton that there was no latitude effect, but he had to retract afterward. Later he was to claim that he and his group had been the first to discover the latitude effect.

His first two important experiments had brought him fame long before the Nobel award in 1923, and he became involved in the organization of science. He played an important part in the early years of the National Research Council. During the First World War he served in the Army Signal Corps to help apply scientific techniques. After the war he returned to Chicago, but was soon persuaded to take on the presidency of the new California Institute of Technology, and the directorship of its physics department. His energy and enthusiasm helped to develop Cal Tech to its present position. At the same time he encouraged and guided a team of first-class physicists.

His conservatism in physics was matched by conservative views on other matters. He was against scientific research being financed by government, against too much government in general, against the New Deal; and he would have been strongly against the welfare state if the term had been in use in his time. The book leaves us in no doubt about his ability, but does not gloss over his occasional obstinacy or his wishful thinking about past errors, matters on which some histories tend to be silent. Millikan was not a revolutionary who started new ideas, but the author stresses—rightly—the importance of men like him for the progress of science.

Russell McCormmach’s Night Thoughts of a Classical Physicist is a very different kind of book. Its subject, Professor Victor Jakob, is invented, but invented with great labor and erudition. The author is a distinguished historian of science, familiar with the realities of the period, and you can almost feel the strain of forcing the imaginary professor into the Procrustean bed of the real history. For example, one of the illustrations is von Menzel’s oil painting Room with a Balcony, which exists, and which shows in the background six portraits, too blurred to be recognizable. The caption refers to “Jakob’s portrait gallery,” and another illustration purports to give this gallery in close-up. Arranged to match the layout of the painting, this now consists of contemporary portraits of the great physicists whom Jakob admired. But the result is confusing, because from the text the portrait gallery is supposed to be in Jakob’s study, while the balcony room in the painting can by no stretch of imagination resemble a study of the period.

The scene is a small unnamed German university town in 1918. Jakob is an elderly, unsuccessful physicist. I suppose he has to be unsuccessful, for if he had made any real contributions, these would have been hard to fit in with the real history of physics. He is very conscious of not having risen to be an “Ordinarius,” or ordinary professor. He is just an honorary ordinary professor, something between an extraordinary (associate) and ordinary (full) professor. In fact he has to teach theoretical physics for apparently no better reason than that he was never given a chair of experimental physics.

In his younger days he wrote some papers, but we are not told their subject, or with what kind of problems he was struggling, except that he believed in the importance of a “world ether.” Of the changes in physics, he seems to have been aware only of the new theory of relativity, which was too mathematical for him, and the developing quantum theory of the atom. I wonder whether his creator has not here endowed him with too much insight; the new atomic theory did indeed exist and had considerable success, but would an old-fashioned physicist really have seen it as the new trend in the subject, which he was reluctant to follow? There is no sign of his reaction to the many contemporary discoveries that were not matters of opinion, such as those of the electron, of X-rays, of radioactivity, all of which gave Millikan the exhilarating feeling of participating in a rapidly developing subject.

Thus Jakob’s “night thoughts” sum up the state of physics only in a rather vague way. He reflects on his lack of success, and he recalls many instances of the lack of good will toward him, from the head of his institute down to the custodian. In his dreams—at least I assume that the passages in italics, with their dreamlike logic, are dreams—the Ministry of Education official, who had the last word about academic appointments in Prussia, appears as a rather intimidating dictator. He also recalls his teachers and friends—the subjects of his portrait gallery—and what he learned from them. Particularly vivid is his memory of Paul Drude, another real physicist, whose suicide came as a great shock to him.

It is wartime, and he thinks about his country. He fought and distinguished himself in the Franco-Prussian war of 1870. He is still a good patriot, but he has become skeptical about the progress of the war, he sees hope for his country in the character and idealism of its people rather than in the control of territory. In fact, he expresses these thoughts in a speech at a patriotic meeting at the opening of the story, and during this speech he suffers a slight stroke. It is during the enforced rest following this that his “night thoughts” come to him.

At the end he dies in a bizarre accident in the mountains near his university town. The notes inform us that this happened to a real physicist. There are forty-five pages of notes, which justify the attribution of opinions to real physicists in their letters or conversations with the invented Jakob, and sometimes explain how Jakob’s opinions and experiences are taken from those of real people. I find that I learn more from these notes than from the rather contrived narrative about an invented person, though he comes very much alive, but that is evidently a matter of personal taste.

The primary preoccupations of the physicists of the time were, of course, the perplexity created by the new facts and by the new insights into old facts, the advent of relativity, more or less complete at the time, and the quantum theory, still in its initial stages and quite incomprehensible to most scientists. In wartime also the need to make new techniques available to the military added to their problems. This last concern was international and can be recognized in the story of Millikan as well as of Jakob. Perhaps the German physicists were more deeply worried about the theoretical difficulties of the new discoveries, partly because of their proximity to the innovators, partly because of the greater number of theoreticians among them.

At the same time the personal squabbles and complaints among the German physicists were more intense than they were elsewhere. There are some of course in any profession, and more among the less able and less successful practitioners. That such tensions are so much more prominent in Jakob’s story than in Millikan’s biography is in part accounted for by Millikan’s being a success story, and Jakob’s one of failure. But from the notes it is clear that such situations were very widespread in the German universities of the period. They are coupled with complaints about appointments, which in Germany were handled by the state ministries. No doubt there are grievances about lack of promotion everywhere, but in America or England there is no centralized authority inviting a centralized feeling of grievance. Of course the question of anti-Semitism came up in connection with appointments and Jakob mentions it, although in spite of the sound of his name, he is not Jewish. There is mild reference to it also in the Millikan story. (Cal Tech could not be expected to appoint two Jews.) One feels that the weight of anti-Semitism in the universities in the two countries at that time was about the same.

In the notes, and reflected in Jakob’s reflections, are the thoughts of many eminent physicists, including Helmholtz, Planck, Einstein, Wien, and others, on many different subjects. Following Jakob’s rambling reflections, they naturally appear in a rambling order. Few of these concern physics and those that do are mostly about semi-philosophical points such as the merits of the old mechanistic world picture, which many of the older physicists were reluctant to abandon, the possibility of replacing it by an electromagnetic world picture, or the difficulty in understanding Bohr’s postulates about the emission of radiation. One misses arguments about more concrete problems, such as how to explain some experiment or how to verify some theory. These must have been discussed and their omission presumably reflects the tastes of Jakob or rather of his creator. The rest of the comments are about personal problems, about squabbles with colleagues and staff, about promotions and appointments, and about physicists’ attitudes to the war; these add up to a picture of a life of physicists of the time.

The book represents much serious research and extensive knowledge of the period. It could have been written only by an eminent historian of science. Whether its unusual presentation makes it easier to absorb the impressions of the history of science that the author wants to convey is a matter of taste that must be left to each reader to judge.

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