From Immigrant to Inventor

by Michael Pupin

I went to Berlin to study experimental physics with Hermann von Helmholtz, the famous professor of physics at the University of Berlin, the formulator of the principle of conservation of energy, and the first interpreter of the meaning of color both in vision and in music and speech. He was then the director of the Physical Institute of the university. His title, conferred upon him by the old Emperor, was Excellenz, and the whole teaching staff of the institute stood in awe when the name of Excellenz was mentioned. The whole scientific world of Germany, nay, the whole intellectual world of Germany, stood in awe when the name of Excellenz von Helmholtz was pronounced. Next to Bismarck and the old Emperor he was at that time the most illustrious man in the German Empire.

I had letters of introduction to him from President Barnard of Columbia College, and also from Professor John Tyndall of the Royal Institution. Professor Arthur Koenig, the right-hand man of Helmholtz and the senior instructor in the Physical Institute, took me to the office of Excellenz von Helmholtz and introduced me as Herr Pupin, a student from America, and the proposed John Tyndall fellow of physics of Columbia College. I was awarded the fellowship three months later. Koenig bowed before his master as if he wished to touch the ground with his forehead. I bowed American fashion, that is, with a bow of the head which did not extend below my shoulders, the same kind of bow which was practised at the University of Cambridge at that time, and I called it the Anglo-Saxon bow; it was entirely different from Koenig’s bow. Helmholtz seemed to notice the difference and he smiled a benevolent smile; the contrast evidently amused him. He had much Anglo-Saxon blood in his veins; his mother was a lineal descendant of William Penn. It was understood in Berlin that he was the most “hoffähig” (presentable at court) scientist in the German Empire.

HERMAN VON HELMHOLTZ

From a painting by L. Knaus

He received me kindly and showed deep interest in my proposed plan of study. His appearance was most striking; he was then sixty-four years of age, but looked older. The deep furrows in his face and the projecting veins on the sides and across his towering brow gave him the appearance of a deep introspective thinker, whereas his protruding, scrutinizing eyes marked him a man anxious to penetrate the secrets of nature’s hidden mysteries. The size of his head was enormous, and the muscular neck and huge thorax seemed to form a suitable foundation for such an intellectual dome. His hands and feet were small and beautifully shaped, and his mouth gave evidence of a sweet and gentle disposition. He spoke in the sweetest of accents, and little, but his questions were direct and to the point. When I told him that I never had an opportunity to work in a physical laboratory and had paid exclusive attention to mathematical physics, he smiled and suggested that I should make up this deficiency as soon as possible. “A few experiments successfully carried out usually lead to results more important than all mathematical theories,” he assured me. He then requested Professor Koenig to map out for me a suitable course in the laboratory and to look after me. Koenig did it, and I shall always be grateful to the sadly deformed and extremely kind little man with bushy red hair and distressingly defective eyesight, which he tried to correct with the aid of enormous spectacles employing lenses of extraordinary thickness. Helmholtz was always mellow-hearted to little Koenig, partly because, I think, Koenig reminded him of his own son Robert, who was deformed in hand and foot and back, but had the magnificently shaped head of his distinguished father.

During my first year’s study in Berlin I attended Helmholtz’s lectures on experimental physics. They were most inspiring, not so much on account of the many beautiful experiments which were shown, as on account of the wonderfully suggestive remarks which Helmholtz would drop every now and then under the inspiration of the moment. Helmholtz threw the search-light of his giant intellect upon the meaning of the experiments, and they blazed up like the brilliant colors of a flower garden when a beam of sunlight breaks through the clouds, and tears up the dark shadows which cover the landscape on a cloudy summer day. These lectures were attended not only by students in physics, mathematics, and chemistry, but also by medical students and army officers. The official world, and particularly the army and navy, paid close attention to what Excellenz von Helmholtz had to say; and I had much reason to believe that they consulted his scientific opinions at every step. I have often been called upon to correct the opinion that Helmholtz was a pure scientist par excellence. There is no doubt that his great work dealt principally with fundamental problems in scientific theory and in philosophy; but there is also no doubt that, like many other German scientists, he was much interested in the application of science to the solution of problems which would advance the industries of Germany. His earliest career is associated with his invention of the ophthalmoscope. The optical glass industry of Germany was being developed by some of his former students, who led the world in geometrical optics, a part of physics to which Helmholtz devoted much attention in his younger days.

One day I was on my way to the institute; in front of me walked a tall German army officer, smoking a big cigar. When we reached the entrance of the institute the officer stopped and read a sign which said: “Smoking is strictly forbidden in the institute building.” He threw his cigar away and walked in. I recognized Crown Prince Frederick in the officer. Two years later he became Emperor of Germany and ruled for ninety days. I watched his footsteps and saw that he entered Helmholtz’s office and stayed there over an hour. He undoubtedly consulted the great scientist on some scientific problem which was then interesting the German army and navy.

Helmholtz’s personality was overpowering and seemed to compel one’s interest in problems in which he was interested, and at that time his principal interest was outside of the electromagnetic theory. Nevertheless, I kept up my interest in Faraday, which interest I brought with me from Arran; but I found no opportunity to ascertain Helmholtz’s opinion concerning Faraday. Finally the opportunity came toward the end of my first year at the University of Berlin.

Gustav Robert Kirchhoff, the famous discoverer, formulator, and interpreter of the science of spectrum analysis, and the founder of the theory of radiation, was at that time professor of mathematical physics at the university. He was considered the leading mathematical physicist of Germany. His contributions to the electrical theory occupied a very high place. The most important of these was undoubtedly his theory of transmission of telegraphic signals over a thin wire conductor stretched on insulated poles, high above the ground. It was a magnificent mathematical analysis of the problem, and it showed for the first time that theoretically the velocity of propagation of these signals along the wire is equal to the velocity of light. The university catalogue announced that he was to deliver a course of lectures on theoretical electricity during the first term of my residence at the university. I attended the course and waited and waited, but waited in vain to hear Kirchhoff’s interpretation of Faraday and Maxwell. At the close of the semester the course ended and the electromagnetic theory of Faraday and Maxwell was referred to on two pages only, out of two hundred; and the part so honored was not, even according to my opinion at that time, the essential part of the theory. In this respect the lectures were disappointing, but nevertheless I was most amply rewarded for my pains. I never heard a more elegant mathematical analysis of the old-school electrical problems than that which Kirchhoff developed before his admiring classes. That was the last course of lectures which he delivered; he died in the following year, and was succeeded by Helmholtz as temporary lecturer on mathematical physics.