IX End of Studies at the University of Berlin
I confess that when I first arrived in Berlin I brought with me old prejudices, which were annoying, to say the least. The Teutonism in Prague, when I was a schoolboy there, had made lasting impressions upon my young mind; they were with me when I landed at Castle Garden. Early impressions are very persistent and cannot be obliterated by time alone. Christian’s father, the innkeeper of West Street, and his friends, the hardy Friesland sailors who taught me how to handle the paint-brush, drew me closer to the German heart, and I found it much less grasping than I thought it was. But the Frieslander of those days had no great love for the Prussian. Bilharz, the idealist of Cortlandt Street, gave me a more intimate knowledge of the German temper, and helped much to dispel many of my early prejudices. But Bilharz displayed decided dislike for the Prussians. The few German friends whom I had during my “greenhorn” days were southern Germans, and they did not appear to be very friendly to the idea of a united Germany under Prussian hegemony. These early experiences encouraged me in the belief that the Prussians were probably responsible for the Teutonism which I disliked. This belief was strengthened by Bismarck’s anti-Russian and anti-Serbian, but strongly pro-Austrian, policy at the treaty of Berlin in 1878. He protested, I knew, that he would not sacrifice the bones of a single Pomeranian grenadier for all the Balkans; but I did not believe him. Hence the uncomfortable feeling of being in an enemy country, when I first came to and settled down in Berlin.
The Teutonism of Prague, more than anything else, was responsible for it. Racial antipathy is one of the saddest of psychic derangements; and, although it is a repulsive product of modern nationalism, the world does less than nothing to get rid of its insidious poisons. European civilization is being destroyed by it. I suffered from its evil effects during the early days of my life in Berlin. Helmholtz, Koenig, and all the officers in the Physical Institute showed me every kindness and consideration, and that prevented me from turning around and speeding back to Cambridge as soon as the first breath of the atmosphere of Berlin gave me an acute attack of anti-Teutonism. My German landlady and her friends, as well as the German students I met in the lecture-rooms, struck no responsive chord in my heart, because it was out of tune with my surroundings. I remained a stranger in a cold, strange land. A young Scotch friend of mine, a graduate of the University of Glasgow, appeared on the scene, some time after I had become settled in Berlin. He kept his promise, given me at Arran, to join me in Berlin. He stayed at the university for one semester only and heard lectures on Roman law. He looked like a northern Apollo: tall and erect, the pink of youth radiating from his handsome face, and the locks of purest gold adorning a lofty brow, which made you believe that you were looking at a young Sir Walter Scott. His deep-blue eyes knew of no suspicions, and his heart had never been touched by the poison of racial antipathy. He loved the world and the world loved him. His knowledge of German was very poor, and yet everybody loved to talk to him. Even the stern Schutzman (policeman), stirred up to white heat by too noisy a rendering of American and Scotch college songs in the slumbering streets of Berlin, was as gentle as a dove when the blue-eyed young Scot stood in front of him and greeted him with a honey-hearted smile. My landlady, quite an aged person, as well as her young boarders, begged me to bring him to dinner as often as possible. “Yes, do bring him,” said a sarcastic young fräulein; “you look quite human and almost handsome when he is around.” There was much truth in what she said; the poison of racial antipathy did not operate in me when he was present. He made friends on every side among the German students, and when I saw how he warmed up to them and how they warmed up to him I began to thaw out myself. Helmholtz and dear little Koenig were the first persons in Berlin who helped me to forget that Europe was made up of different races who lived in eternal suspicion of each other. After that, following the example of my Scotch friend, I began to rid myself of the poisonous infection which I received from the Teutonism in Prague; but it was a slow process. Helmholtz’s address on Faraday was so warm and so generous to Faraday as well as to Maxwell, and so wonderfully just, that I began to question the justice of my anti-Teutonic prejudices.
The two volumes of Helmholtz’s addresses and public speeches which I enjoyed so much during that summer in my mother’s vineyard made me almost repentant. My mother knew of my anti-Teutonic sentiments and never approved of them. One day we drove to visit my younger sister, who lived about fifteen miles from Idvor. On the way we passed through a large village, Echka, having a mixed population of German, Rumanian, and Serb peasants. There was a striking contrast in the appearance of the houses, of the people, and of their methods of moving about in the pursuit of their daily work. The German peasants were far ahead of the Rumanians as well as of the Serbs. My mother called my attention to it, but I made no comment. Presently we passed the stately Roman Catholic church of the village, which looked like a cathedral. It was built, I was told, by the German peasants of Echka, and my mother told me that it was crowded on Sundays and holidays, and that the priest was a very learned and a very good man. When we passed the Orthodox church, which was quite small and insignificant-looking, my mother said: “Would you not feel ashamed if St. Sava came down to earth again and after seeing that splendid German church looked at this hut which is called the Orthodox church? But small as it is you will never find it filled except at some weddings or at memorial services for some departed rich person, when people expect much feasting.”
Again I made no comment, because I was opposed to “alien intruders” myself, as some people called the German colonists; and my mother looked disappointed. Just then we saw two peasant girls carrying river water in shining copper vessels. These vessels were suspended at the ends of a long flexible staff which was nicely balanced on the shoulder of each young carrier, so that one vessel was in front and one behind her. The first girl was a blonde with slippers on her feet; a simple dark-blue dress covered her youthful figure and displayed the successive phases of her rhythmical movement. It was synchronized with the swinging motion of the bright copper vessels, which moved up and down like a double pendulum, bending the flexible shaft around its point of support on the shoulder of the fair carrier. The copper vessels, although filled to the brim, did not spill a single drop of water; the perfect adjustment of the swinging motion of the carrier to that of the swinging shaft produced this admirable result. The girl, the staff, and the shining vessels stood in a beautiful harmonic relation to each other. They reminded one of the harmonics in a sweet musical chord. It was a beautiful sight, and I said so. My mother, noticing my sudden burst of enthusiasm, sounded a warning. “She is a German girl,” she said, “and she certainly is lovely. Her heart and soul are in her job. But if you find one like her in Berlin, remember your promise; you must marry an American girl if you wish to remain an American, which I know you do.”
She evidently had become a little alarmed at the thought that her praises of the Germans might cause my sentiments to swing too far the other way. The second water-carrier was a barefooted and gaudy-looking lassie, who stepped along any old way and marked her track with frequent splashes of water from the copper vessels. “She is a wild Rumanian,” exclaimed my mother; “she can dance like a Vila, but she hates her job of carrying water. You will never find one like her in Berlin. The Germans have no use for people who do not love their daily duties.” My mother was a great admirer of the thrifty and industrious German colonists in Banat, whom she always recommended as models to the peasants of Idvor. When she heard my praises of Helmholtz and my confession of racial antipathy to the Germans she put up many powerful arguments which were most convincing. They had a wonderful effect.
When I returned to Berlin from Idvor things looked more inviting, and my landlady remarked that I looked much more cheerful than I did a year before, when I arrived from Scotland. In another year, she suggested jokingly, I might look as cheerful as a real Prussian, particularly if I should succumb to the charms of a Prussian beauty. Remembering the promise that I had given to my mother about marrying an American girl, I said to my landlady: “Never! I have already pledged my word to one who is nearer to my heart than any Prussian beauty could ever be.” “Ach, Herr Pupin, you have changed most wonderfully,” exclaimed the landlady, and then she added in a whisper: “Just think of it! To get a confession on the first day of your return which I could not get before in nearly a year! I understand now why you were always so distant to the young ladies in my pensionat.” But the change of feeling, speeded up by my mother, and noticed by my landlady, was speeded up almost as effectively by another Serb.
A Bosnian Serb with the name of Nikola had a fine cigarette shop on Unter den Linden, the principal avenue of Berlin. It was within a stone’s throw from the Imperial palace, and the highest aristocracy of Berlin patronized it. He was a rough diamond, and would stand no nonsense from any prince or count. If they found fault with his famous Turkish cigarettes he did not hesitate to tell them to buy them somewhere else. But he prospered, he said, because these German aristocrats never resented straight talk from man to man. He laughed at me, when I mentioned to him my suspicions and antipathies; and begged me to pass with him, from time to time, an hour or so in his store, and watch his German customers. I did, and profited much. The Prussian aristocrats had no racial antipathy against a Serb, if their apparently genuine affection for Nikola had any meaning. Nikola never left them in any doubt as to his pride of being a Serb.
Half-way between Nikola’s store and the Imperial palace was an old chop-house, called Habel, dating from the time of Frederick the Great. Frederick’s generals always stopped there for a glass of wine, when they returned from an audience with the king. The custom persisted and was still in existence when I was a student in Berlin. Nikola often invited me to early luncheon at this chop-house, and there we saw the great generals and marshals of the German Empire, sitting around a long and separate table and taking a glass of wine after returning from the Imperial palace, from their daily audience with old Emperor William. It was a wonderful sight; those tall, broad-shouldered, deep-chested, brainy, and serious-minded Teuton warriors inspired tremendous respect. Nikola assured me that he knew many of them personally, they being his customers, and that as human beings they were as gentle as doves. “Many a time I called them down when they joked about my cigarettes, and they submitted without a murmur. Do you call that arrogance?” asked Nikola, throwing out his chest and trying to look as stern and as imposing as any of the generals present.
Once he took me to an avenue where Moltke used to walk and showed me the great field-marshal, who was then eighty-six years old, but still as straight as an arrow. “Did you ever see a more modest and thoughtful or a more spiritual-looking man anywhere?” asked Nikola, and I confessed that I had not. “Then stop your talk about Prussian pride!” exclaimed Nikola. On another occasion we walked to the park and he showed me Bismarck, riding on horseback, a friend and an adjutant accompanying him. Nikola saluted him and so did I, and Bismarck saluted back graciously. “Does he look like a brute, or like a fool who would try to convert by force all the Slavs into Germans?” asked Nikola, poking fun at my anti-Teutonic suspicions. “No,” said I, “I do not think he does; in fact, I think he looks very much like Helmholtz, except that there is much less spirituality in his face than in that of the great scientist.” “Helmholtz!” exclaimed Nikola, “even he would lose his saintly expression, if he had to carry the load of the whole empire upon his shoulders, the socialists on the top of his load pushing it one way, and the clericals at the bottom pushing it the other way.”
Nikola was born in Bosnia when the Turks ruled supreme, and hence he was not much of a scholar; but he was a careful listener, and always thought through his own head; his judgment was remarkable, I thought. He knew who’s who and what’s what in Berlin better than many a foreign diplomat there. He used to joke about it, saying that his knowledge was expected of him, because he was the next-door neighbor of the great Kaiser. The Serbs of Banat did not seriously dislike the German colonists there, nor did the colonists dislike them, and they delighted in speaking the Serb language. They called each other “komshiya,” neighbor. The Serbs, in general, use this word when they refer to a German in a friendly way. Nikola always referred to the great Kaiser as his “komshiya”; many of his customers knew that and enjoyed it hugely. They returned the compliment and often addressed Nikola with the Serbian word “komshiya.” “Come and see my komshiya,” said he one day to me, and there I stood for the first time in front of the Imperial palace and waited for the old emperor to show himself at the window. He did that almost every day about noontime when the guards marched by on their daily parade. Presenting arms and looking straight at the old emperor, they marched by like a single body animated by a single heart and a single soul, and they spanked the ground with their vigorous goose-step, the rhythmic strokes of which could be heard quite a distance away through the ringing cheers of the enthusiastic crowd. “Do you know what that means?” asked Nikola. I answered “No,” and he said: “It means that every German looks up to his fatherland for orders, and the perfect rhythm of that goose-step means that every German will obey these orders and finish on time any job for the good of the fatherland that may be assigned to him. It is the symbol of German unity.” That was Nikola’s unique interpretation; I never heard anybody else interpret it that way. But Nikola had a lively imagination and he evidently wished me to get a favorable interpretation of everything the Germans did.
Between my young Scotch friend, my mother, Nikola, and my professors in the Physical Institute, I soon forgot the unpleasant memories of the Teutonism in Prague, and Berlin no longer looked to me like a Thraenenthal, a valley of tears, as my old friend Bilharz in Cortlandt Street would have called it. I soon found myself enjoying warm personal friendships of German fellow students and of the professors, and it was a very fortunate thing; it was providential. Nothing but the love of God and the friendship of man can give that spiritual power which one needs in moments of great sorrow. One day in the beginning of winter, of that year, a letter arrived from my sister, telling me that my saintly mother was no longer among the living. I vowed on that day that her blessed memory should be perpetuated as far as an humble mortal like myself could do it. Twenty-seven years later the Serbian Academy of Sciences announced that the income of a foundation in memory of Olympiada Pupin would be expended annually to assist a goodly number of poor schoolboys in Old Serbia and Macedonia.
The vanishing of a life which is an essential part of one’s own life produces a mysterious shift of the direction of one’s mental and spiritual vision. Instead of searching for light which will illuminate the meaning of things in the external physical world, as the vision of young people usually does, it begins to search for light which will illuminate the meaning of what is going on in the internal world, the spiritual world of our soul. The question “What is Light?” was no longer the most important question of my thoughts after my mother’s death. The question “What is Life?” dominated for a long time my thoughts and feelings. I became introspective, and, being a somewhat temperamental person, like most Slavs, I might have lost my way forever in the labyrinth of all sorts of metaphysical structures of my own creation. Providence came to my rescue. Two American students with aspirations in science similar to mine joined the Physical Institute. One of them, a Harvard graduate, the late Arthur Gordon Webster, was the very distinguished professor of physics at Clark University; the other, a Johns Hopkins man, Joseph Sweetman Ames, is now the director of the physical laboratory at Johns Hopkins and a worthy successor to the famous Henry Augustus Rowland. Their truly American enthusiasm and directness prevented me from relapsing into the drowsy indefiniteness, sometimes called idealism, of a temperamental and sentimental Slav. They told me many wonderful tales of the higher endeavor in science at Harvard and at Johns Hopkins. The new Jefferson Physical Laboratory at Harvard was a wonder, according to Webster; and Ames never grew weary of extolling the beauties of Rowland’s wonderful researches in solar spectra, and I never grew weary of listening to them. At times, however, I wondered why these two men had ever come to Helmholtz when they were so well off at home. Ames wondered, too, and he returned to Rowland at the end of the year; but Webster stayed, although in my presence he never admitted unreservedly that the Physical Institute in Berlin was very much better than anything they had at Harvard. Webster’s and Ames’s testimony convinced me that the great movement in the United States for higher endeavor in science was making rapid progress; and I longed to finish up my studies in Berlin and return to the United States. After my mother’s death Europe attracted me much less.
A new physical science was attracting much attention in Germany at that time, the science of physical chemistry. Helmholtz was very much interested in it. I had read his latest papers on the subject and they reminded me of what I had seen in Maxwell’s book on heat about Willard Gibbs of Yale. I soon discovered that the alleged German fathers of the new science were anticipated by Gibbs by at least ten years. Remembering the charge of De Tocqueville that the American democracy had never done anything for abstract science, I made a careful note of my find. It was a clean-cut little discovery, I thought, and Helmholtz admitted it. He suggested even that I might find material in it for a research leading to a doctor dissertation. I embraced the suggestion and started an experimental research, at the same time studying the theories of Gibbs, Helmholtz, and other authorities, mostly German, on physical chemistry. The more one penetrates the depths of any problem the more he yields to the belief that this problem is the most important problem in the world. This happened to me; and the Faraday-Maxwell electromagnetic theory was shelved, temporarily, on account of my interest in physical chemistry, and particularly on account of the prospect of finding there a doctor dissertation, which I finally did.
At the end of the first semester and at Webster’s suggestion he and I, in the spring of 1887, went to Paris for a short visit. We wished to see what physical science was doing at the Sorbonne and at the Collège de France, and to compare the academic world of Paris with that of Berlin. We stayed there three weeks and learned quite a number of novel and interesting things. The architectural beauties of Paris as well as its art galleries and museums made a profound impression upon me. As a record of a magnificent old civilization Paris, I thought, was incomparably ahead of Berlin. The spirit of Laplace, La Grange, Fourier, Ampère, Arago, Fresnel, Foucault, and Fizeau was very much alive in the ancient halls of the Sorbonne and of the Collège de France. The background of a former glorious period of physical science in France was much more impressive in Paris than the corresponding background in Berlin. But for every one of the great savants in physical and mathematical sciences, who were active in Paris at the time of my visit, like Poincaré, Hermite, Darboux, Appel, Lippmann,one could name several in Berlin. And there was nobody in Paris who, in my opinion, could measure up to Helmholtz, Kirchhoff, and DuBois Reymond. There was no statesman there of Bismarck’s caliber, and no general like Moltke. I saw no warriors who looked like the magnificent fellows whom Nikola first exhibited to me at the long table in Habel’s. General Boulanger was very much in the limelight. I saw him at a great official reception, and I should have felt very sorry if the destiny of France had been intrusted to him. The physical and chemical laboratories were rather poorly equipped and compared unfavorably with the corresponding laboratories in Berlin. The draped statues in the Place de la Concorde, testifying to France’s grief for the loss of Alsace-Lorraine, completed the picture of Paris in my mind, which was anything but cheerful. France, I thought, had not yet recovered completely from her wounds of 1870–1871, and I felt sorry. Two years earlier I had passed through Paris on my way from Pornic to Idvor and had carried away a much more cheerful picture. But at that time my observations, covering barely two days, did not see much; and, besides, I did not know Berlin at that time and could make no comparisons. If Paris reflected the spirit of France and Berlin that of Germany, then France, I thought, was a falcon with broken wings and Germany was a young eagle that had just discovered the wonderful power of its pinions. The wonderful intellectual and physical vigor of the new empire impressed powerfully every foreign student at the University of Berlin when I was a student there. This gave me much food for thought and I searched for explanations.
There was one explanation which always appealed to me much on account of its simplicity. I heard it from a very learned German. This was his story: The German iron always contained phosphorus, including also the great deposits of iron which the Germans had found in Alsace-Lorraine. The only good iron that Germany had prior to 1880 was that in the Iron Chancellor. Hence, Germany could not build up a steel industry, and without it no great industrial development is possible in any country. A miracle happened; a young Englishman, a clerk in a London police court, made a discovery which was destined to give Germany its great steel industry. This was Sidney Gilchrist Thomas, who discovered the so-called “basic Bessemer” process. It made iron containing phosphorus easily available for the manufacture of iron and steel products. This started the modern steel industry of Germany in the early eighties. Many a street in the towns of the German steel districts was named in honor of Gilchrist Thomas. “This,” said my informant, “is the power which, as you express it, the young German eagle has discovered in its pinions.” I suspected that the object of his story might have been to discourage an opinion on my part that the remarkable vigor of Germany was derived from the weakness of France. Hence I looked up the data of his story, but I found them correct. Years ago I told this story to the late Andrew Carnegie, and he agreed with my German informant. To-day I am convinced that neither the great works of Krupp, nor the great German navy, nor many other things which have happened since my Berlin days, would have been possible without the start which was made with the aid of Gilchrist Thomas.
Another remarkable assertion from the same informant made a lasting impression. According to him, united Germany would not have endured very long, if it had not been for the rapid rise of the German steel industry and of other German industries which followed in its wake. The organization of Germany as an economic unit secured the organization of Germany as a political unit. He summed it up by saying that Bismarck and Moltke had raised the structure of the German Empire, but that Gilchrist Thomas had built a steel ring around it which prevented it from falling to pieces. He added then a corollary to this startling statement, and I repeat it here in the form of a question. If the scientific research of a young clerk in a London police court, who studied chemistry in a London evening school, could do so much for Germany, how much can one reasonably expect from the great research laboratories of the German universities and technical schools? This, according to my informant, had become a national question in Germany. This information reminded me that the great movement in Great Britain and in the United States for higher scientific research was also present in Germany, but in a much more advanced form. My informant called my attention to Werner von Siemens’s pioneer work in this German movement.
Ernst Werner von Siemens was at that time, next to Helmholtz, the most admired scientist in the German Empire. He was the head of a great electrical plant in the heart of Berlin, and was known everywhere to possess a splendid combination of talents in abstract science and engineering. Men of that type were quite rare in those days, and they are very rare even to-day. I heard a great deal about him in a course of lectures on electrical engineering which I attended at the Polytechnic School of Berlin. I saw him several times, when he called at the Physical Institute on his friend and relative by marriage, Excellenz von Helmholtz. His remarkable appearance made a strong impression upon me, and I longed to see his great plant, where all kinds of electrical things were made, from the finest electrical precision instruments to the largest types of dynamos and motors, many of them his own inventions. As a sign of special favor Helmholtz gave me a note of introduction to his distinguished friend, who received me graciously and gave me to an official who took me around the great electrical plant, the first that I had ever seen. The impression which it made upon my mind was certainly wonderful, but not more wonderful than the impression which the great personality of Siemens had made upon me. The more I learned about him the more I became convinced that no industrial organization ever had a presiding genius of greater attainments than Siemens. His attitude toward abstract science and its relation to the industries is best described by mentioning here a fact which is of great significance in the history of physical science. He founded in that year, 1887, the great Physical-Technical Institute, and presented it to the German nation; Helmholtz was its first president. The modern science of radiation rests upon a foundation first laid by Kirchhoff and greatly strengthened by additional experimental data obtained in this institute under the guidance of Helmholtz. Planck, the successor of Kirchhoff at the University of Berlin, already in office before I left Berlin, was undoubtedly inspired by these experiments when he formulated his great law of radiation which forms to-day the last word in the science of radiation, a great science which justly bears the mark “made in Germany,” just as the electromagnetic theory bears the mark “made in England.” The Physical-Technical Institute will always stand as a memorial to the man who preached in Germany the doctrine of the closest co-operation between abstract science and the industries. Germany adopted it first; the United States adopted it many years later. Helmholtz and Siemens always represented to me the highest symbol of this co-operation.
Bismarck and Moltke, Helmholtz and Siemens, were the great power which the young German eagle had discovered in his pinions; and he flew as he had never flown before, and his flight astonished me when I was a student in Berlin. He who wants to know the real Germany of the eighties should study the lives of Bismarck and Moltke, of Helmholtz and Siemens. They, I firmly believed at that time, were the leaders of the German constructive thought and action; they were the fathers of united Germany just as Washington and Hamilton, Franklin and Jefferson, were the fathers of this country. But would the spiritual influence of the fathers of united Germany produce a German Lincoln? I knew the historical background of the Declaration of Independence and also its historical foreground too well to answer this question in the affirmative. Extraordinary men can do extraordinary things, but the course of a nation’s destiny will always be guided not by transient efforts of one or even of several extraordinary men of a given period, but by the persistent power of the nation’s traditions.
My visit to Paris was to supply me with more knowledge of the academic world of France, and also with some fresh food for thought relating to my problem in physical chemistry, and it did in a measure. But the current of thought which was started by some of the strongest mental stimuli which I received in Paris had nothing to do with either physical chemistry or with academic France; it ran into German channels which I described above. These were the channels which ran through the minds of most university men in Germany, and in these channels every problem in art, science, and literature was viewed at that time from the standpoint of German economic and political unity. My German scientific friends, particularly those in eastern Prussia, where I spent the summer vacation of 1887, would rather discuss those problems than the problems in physical chemistry or in the electromagnetic theory. It took me some time after my return from Paris to get back completely to my research in physical chemistry. But no sooner had I gone back to it than the irresistible power of the current of big events, following each other in quick succession, took me away from it again. I shall describe them in their historical order, but only in so far as they are related to the main thread of my narrative.
One of the many sources of inspiration at the University of Berlin was the Physical Society which met once a month at the Physical Institute. The research students of the institute were admitted to these meetings, and one can imagine what an inspiration it was to them to see and to hear the scientists like Kirchhoff, the great mathematical physicist, DuBois Reymond, the great physiologist, Hoffman, the great chemist, and Helmholtz, the greatest of them all. I often imagined while attending these meetings and listening to the learned remarks of these scientific giants, that I was a lucky mortal who by some strange accident had found himself suddenly among the great heroes in Walhalla. Helmholtz usually presided, and his impressive physiognomy suggested a Wotan presiding at a gathering of the Teuton gods in Walhalla. Whenever I hear Wagner’s Walhalla motif I am reminded of those memorable scenes in the Physical Institute in Berlin, the scenes of victory of the immortal mind of man over mortal matter.
At one of those meetings, which took place toward the end of 1887, many scientific giants of the university were present and Helmholtz presided. There was an atmosphere of expectancy as if something unusual was going to happen. Helmholtz rose and looked more solemn than ever, but I noticed a light of triumph in his eyes; he looked like a Wotan gazing upon the completed form of heavenly Walhalla, and I felt intuitively that he was about to disclose an unusual announcement, and he did. Referring to Doctor Heinrich Hertz, a former pupil of his and at that time professor of physics at the Technical High School in Karlsruhe, Helmholtz solemnly announced that he would describe some remarkable experimental results which Hertz had obtained by means of very rapid electrical oscillations. He then described in his inimitable way a preliminary report which Hertz had sent him, pointing out, in a most lucid manner, the bearing of these experiments upon the Faraday-Maxwell electromagnetic theory, and affirming that these experiments furnished a complete experimental verification of that remarkable theory. Everybody present was thrilled, particularly when Helmholtz closed with a eulogy of his beloved pupil, Hertz, and with a congratulation to German science upon the good fortune of adding another “beautiful leaf to its laurel wreath.” That thrill soon reached the physicists in every physical laboratory in the world; and for a number of years after that memorable announcement most investigators in physics were busy repeating the beautiful Hertzian experiments. The radio of to-day is an offshoot of those experiments.
This is no place to go into a detailed description of what Hertz did. The fundamental idea underlying his beautiful research and its relation to the Faraday-Maxwell far-reaching electromagnetic theory can be described in very simple terms. The wonderful achievements of radio broadcasting alone, to say nothing of other much more important achievements, demand this description. That idea, like the tiny seed hidden in a beautiful flower, lay hidden in Faraday’s visions and in Maxwell’s wonderful, but, to most ordinary mortals, enigmatic interpretation of them. Hertz, guided by his great teacher, Helmholtz, caught the hidden seed and out of it grew a physical embodiment of the Faraday-Maxwell theory, represented by ideally simple apparatus, operating in an ideally simple way. The apparatus and its operation are now the heart and soul of a new art, the radio art, a beautiful daughter of the beautiful mother, the Faraday-Maxwell electromagnetic science. The following description of Hertz’s apparatus and of its operation was the theme of popular lectures and of many conversations which I had with my friends who were not physicists by profession. It represents quite closely the simple picture which I carried away in my mind from that memorable meeting of the Berlin Physical Society thirty-six years ago.
Two equal metal spheres A and B, each twelve inches in diameter, and each carrying copper rods C and D, are placed as indicated in the diagram given here. At E is an opening of about three-tenths of an inch in length, the so-called air-gap. By means of two wires e and f, connected to an electrical machine, the spheres are charged, one receiving a positive electrical charge denoted by the (+) sign, and the other a negative one, denoted by the (-) sign. The air-gap E insulates one sphere from the other, and its function is to make it possible for the electrical machine to increase the two charges until a very high electrical tension is reached. When the electrical tension between the two charges, acting through the air-gap E, is sufficiently high, then the insulating power of the air-gap is overstrained and suddenly it breaks down and becomes conductive and permits the two charges to rush toward each other. The conductivity of the air-gap suspends the action of the charging machine. A large current passes then between the two spheres along the rods and through the air-gap E which is heated by the current to white heat. It becomes then a very good conductor and permits the charges to pass through it easily. The collapse of the air-gap is reported by the sharp crack of the electrical spark which is due to the very sudden heating and expansion of the air in the air-gap produced by the passage of the electrical current. It is a miniature lightning. The two charges reunite, the spheres are discharged, and after that the air-gap E recovers quickly from its breakdown and becomes an insulator again. The process is then repeated by the action of the machine and a rapid succession of sparks can be maintained, each one of them announcing by the crack of the spark the reunion of the charges that had been pulled apart and forced to the surfaces A and B by the action of the electrical generator.
All this was known long before Hertz. The first experiment of this kind I saw in Panchevo in my boyhood days, when my Slovenian teacher Kos explained to me the theory of lightning according to the views of Benjamin Franklin, a theory which clashed with the St. Elijah legend of Idvor and nearly proved me guilty of heresy. But there was something in these electrical discharges that Benjamin Franklin did not know, and that knowledge was first suggested by another great American scientist, a scientist even greater than Benjamin Franklin was in his day.
As far back as 1842 our own Joseph Henry performed experiments similar to those performed by Hertz, and he inferred, prophetically, that the discharge was oscillatory. Nobody ever suggested this idea before, but Henry’s experiments permitted such an inference. Its oscillatory character was then demonstrated mathematically in 1853 by Professor William Thomson of Glasgow, and his calculation was proved to be correct by many experimental tests covering a period of over twenty-five years, and thus the electrical oscillator, similar to the one employed by Hertz, became a well-known apparatus.
What, then, was the novel element in the Hertzian work? It was, broadly speaking, his demonstration that the space surrounding the oscillator (the spheres with their rods) participates in the electrical oscillations in perfect agreement with the Faraday-Maxwell theory; a participation which was foreign to all previous electrical theories. In other words, he detected in the old electrical-oscillation experiments a new action, never detected nor even dreamed of before. He discovered the electrical waves in the space outside of the oscillator. Remembering the impression which Helmholtz’s lecture on Faraday made upon my mind, I was certain at that time that nobody in Continental Europe but one of Helmholtz’s pupils like Hertz could have predicted that there was in these well-known electrical oscillations a new action, an action demanded by the Faraday-Maxwell theory. A simple analogy will, I trust, help much to illustrate the new action which Hertz expected when he started out to search for an experimental test of the modern electromagnetic theory. No scientific expedition ever started out in search of scientific treasures and returned with a richer load.
Here is the analogy:
If by the force of our fingers we deflect the ends of the prongs of a tuning-fork and then let go, the prongs will return to their normal position after performing a number of vibrations of gradually diminishing amplitude. The state of rest is reached when the energy of bending, produced by the work of our fingers, has been expended, partly in overcoming the internal friction in the tuning-fork, partly in overcoming the reactions of the surrounding medium, the air; this last effect results in sound-waves which are radiated off into space. The stiffness and the mass of the prongs of the fork determine the period of vibration, that is, the pitch of the fork.
I confess that in the course of my life since my Berlin days I afforded considerable amusement to my friends whenever I tried to explain to them the Hertzian experiments by appealing to what I considered a well-known action of the tuning-fork. Some of them objected on the ground that this action is just as difficult to understand as the action of the Hertzian oscillator. I met this objection by describing to them the action of the reed in Serbian bagpipes which I watched when I was a boy, and understood sufficiently well to recognize later in the action of the tuning-fork a performance similar to that of the reed in the Serbian bagpipes. I understood the tuning-fork because I understood the reed. An educated American, I claimed, should find no difficulty in understanding the action of a simple mechanism which an uneducated Serbian peasant boy understood.
The Hertzian electrical oscillator, described above, acts like the tuning-fork. The process of pulling apart the two charges, the positive from the negative, and of forcing them to the surface of the spheres by the action of the electrical machine, is a parallel to the process of deflecting by the pressure of our fingers the prongs of the tuning-fork from their normal position. In one case the tuning-fork by its elastic stiffness reacts against the bending of the prongs. In the electrical case the electrical lines of force in the space surrounding the oscillator react against the action of the machine which crowds them into this space by stretching and compressing them. This is the picture of the action of the lines of force which Faraday gave me on the island of Arran, but I did not understand it. In the picture the dotted curves are the Faraday lines of force and the arrow-heads indicate the direction of the electrical force. The Hertzian oscillator, and what Helmholtz had told me before, made Faraday’s language and thoughts much more intelligible. The work done by the machine is all expended upon the stretching and compressing of the lines of force into the space outside of the spheres, that is, upon the electrification of that space.
Compare now the motion of the tuning-fork, after the pressure of the fingers has been removed, to the electrical motion when the air-gap has broken down and the action of the electrical generator suspended. The prongs are driven back to their normal position by the elastic reaction due to the bending; but when they reach that position they are moving with a certain velocity, and their momentum carries them beyond that position; they move on until the energy of the moving mass has been expended in the work of bending the prongs in the direction opposite to that of the original bending. The prongs begin then to move back in the opposite direction, starting the second cycle of motion. The same line of reasoning will carry us into the third and fourth and every succeeding cycle of motion. It is obvious that these cycles will follow each other during equal intervals of time, which gives a definite pitch to the tuning-fork. A periodic motion of this type is called an oscillation or vibration; and it is clear that it is a periodic transformation of the energy of elastic bending into energy of motion of the mass of the prongs including the surrounding air, and vice versa. The motion is finally reduced to rest when the energy of bending, produced at the start by the work of the fingers, has been used up. The question, what has become of that energy? is very important in this connection. The answer is: It is used up partly in overcoming internal friction and partly in overcoming the reactions of the surrounding air, which result in sound-waves. A sound-wave is a short name describing the physical fact that in the air here are compressions and dilatations alternating at periodically recurring intervals. The production of sound-waves in the air is a proof that the air in the space surrounding the tuning-fork participates in the motions of the tuning-fork.
A perfectly analogous experiment was performed by Hertz with his electrical oscillator, and his principal object was to find whether the electrical field, that is, the electrified space surrounding the oscillator, reacted as did the air driven by the vibrating tuning-fork; if it did it would develop electrical waves. If these electrical waves actually existed, what did Hertz expect them to be? In the description of the oscillator and of its action, given above, two things only were mentioned: the action of the electrical machine which charges the oscillator and the reaction of the lines of force against the tensions and pressures which crowd them into the surrounding space. The electrical waves can, therefore, be nothing else than periodic variations of the tensions and pressures in the lines of force, that is to say, periodic variations in the destiny of the lines of force in the space surrounding the oscillator. This was what Hertz had found.
The breakdown of the air-gap in the electrical oscillator and the consequent suspension of the action of the electrical generator is analogous to the removing of the pressure of the fingers from the prongs of the tuning-fork. The electrical charges on the spheres with the lines of force attached to them, strained by tensions and compressions, are released, and they move toward each other through the conducting air-gap. Just as the prongs of the tuning-fork, after the pressure of the fingers has been removed, cannot remain in the strained position in which they have been bent, so the electrical lines of force, after the insulating air-gap has broken down and the action of the machine been suspended, cannot remain in the position to which they are stretched; they contract, and hence their positive terminals on one sphere and the negative on the other move toward each other. The motion of the strained lines of force with their terminals, the charges on the spheres, has a momentum. Maxwell was the first to show that the momentum of the moving electrical lines of force is equal to the number of magnetic lines of force which, according to Oerstedt’s discovery, are produced by the motion of the electrical lines of force.
The motion of the electrical lines of force has not only momentum but also energy. Employing Faraday’s mode of expression we can say that the electrical energy of the stretched electrical lines of force is thus transformed into energy of the electrical motions. This is perfectly analogous to the passage of the elastic energy of the bent prongs of the tuning-fork into the energy of motion of the moving mass of these prongs. Again, just as the momentum of the moving mass of the tuning-fork bends the prongs in the opposite direction and continues this bending until that motion has disappeared, so the momentum of the moving electrical lines of force will stretch again the electrical lines of force and continue this stretching until the energy of motion has disappeared, when the two spheres are charged again, but in the direction which is opposite to that in the beginning. A new cycle of electrical motion is then started again by the stretched electrical lines of force, repeating itself in an oscillatory fashion until the original electrical energy, produced by the charging electrical machine, has disappeared.
But where has the energy gone? This question is just as important in this case as it was in the case of the tuning-fork. The old electrical theories answered this question one way, and Maxwell, inspired by Faraday, answered it in another. The old theories maintained that there is no other electrical motion except the motion of the charges along the conducting surface of the spheres and the rods. They paid no attention to the motion of the lines of force, because they knew nothing about them. Their vision did not see the lines themselves but only their terminals, the charges. Hence, according to the old theories, all of the energy imparted by the machine is transformed into heat in the conducting parts of the oscillator.
Hertz was the first to prove that a part of the energy is radiated off into space, in a similar manner as the energy of a tuning-fork is radiated off in the form of sound waves. He detected in the space surrounding the oscillator the presence of electrical waves, that is, periodically recurring variations of the density of the electrical lines of force; he measured their length, and, having calculated the period of his oscillator, he divided the wave-length by the period and obtained the velocity of propagation. It came out, in his earliest experiments, roughly equal to the velocity of light, as the Faraday-Maxwell theory had predicted. The waves were reflected and refracted by insulators denser than air, and all these and other effects Hertz demonstrated to follow the laws which hold good for light, supporting admirably Maxwell’s theory that light is an electromagnetic disturbance. Even this preliminary report which Hertz had sent to Helmholtz convinced everybody that the Faraday-Maxwell electromagnetic theory had triumphed, and that our knowledge of electromagnetic phenomena had been wonderfully extended. Subsequent experiments by Hertz and others added more and more laurels to this first victory.
That meeting of the Physical Society in Berlin was what I always considered the inauguration day of the electromagnetic theory. Prior to that day the theory existed in all its beautiful completeness, but it dwelt on high in the celestial heights of Faraday and Maxwell. Continental physicists needed the guidance of a Helmholtz to reach these heights. After that day it came down to earth and lived among mortal men and became part of their mode of thought. It was a heavenly gift which Hertz brought down to earth. Everybody was convinced that the science of light had become a part of the science of electricity.
This new knowledge was the second great revelation of the nineteenth century. The wonderful things which followed in its wake, even before the nineteenth century had closed, testify to the greatness of that revelation.
I have often asked myself the question, Why did not our Joseph Henry, who discovered the oscillatory electrical motions and operated with apparatus similar to that employed by Hertz, pursue his studies further than he did in 1842? and why did not Maxwell, the formulator of the modern electromagnetic science, perform those ideally simple experiments which Hertz performed? The knowledge of the electrical oscillator was the same in 1865 as in 1887, and Maxwell undoubtedly had that knowledge. History offers an answer to these questions and this answer throws a splendid light upon the character of these two great scientists.
Soon after 1842 Joseph Henry resigned his professorship at Princeton College, and bade good-by to his laboratory where he had made several of his splendid discoveries, and where in 1832 he had constructed and operated the first electromagnetic telegraph, one of the practical results of his great discoveries. This happened long before Morse had ever been heard of. Henry’s fame among men of science was very great and promised to grow even greater if he continued his scientific researches. He was still in his prime, only a few years over forty. But a patriotic duty called him to Washington, where the Smithsonian Institution waited for his skilled hand to organize it and to defend it against the scheming politician. This duty tore him away from his beloved laboratory, and he spent the rest of his life, over thirty years, in Washington as secretary of the Smithsonian Institution, as originator of most of the national scientific bureaus of which this country is proud to-day. He was also the first president of the National Academy of Sciences, chartered by Congress in 1863, thanks to his efforts. Physical science under his leadership had rendered valuable service to the country during the Civil War, and the congressional charter to the National Academy of Sciences was a graceful recognition of this service. I have already pointed out Joseph Henry’s splendid efforts for the advancement of scientific research in this country and shall return to it later. He was a great scientist, but he was also a great patriot; his country stood first and his own scientific achievements and fame stood second in his heart. That, I am sure, was the reason why he did not pursue any further than he did his researches of electrical oscillations. I will mention here that one of the most gratifying results of my humble efforts was the naming of an electrical unit after his name. My colleague, the late Professor Francis Bacon Crocker of Columbia University, joined me most enthusiastically in these efforts; and the Electrical Congress in Chicago in 1893, at which Helmholtz presided, adopted the name Henry as the unit of electrical inductance; the unit Farad was named in honor of Faraday. No other electrical units are in more frequent use than the Farad and the Henry, particularly in the radio art. No other men contributed to this art as much as Faraday and Henry did.
Maxwell resigned his professorship at King’s College, London, at the end of 1865, soon after he had communicated to the Royal Society his great memoir on the electromagnetic theory. The electromagnetic theory of light which, as I pointed out before, he had called “great guns” in a letter addressed to a friend, was the climax of it. He retired to his country place, Glenlair, in Scotland, and for five years he was free to devote his entire time to study and meditation. That was the highest joy of his life. But the Duke of Devonshire, a loyal Cambridge man, had presented the university with a goodly sum of money for the building and equipment of a physical laboratory. It was to be named the Cavendish laboratory, after Lord Cavendish, the Duke’s illustrious ancestor, who had devoted his life to electrical science. This gift was the Duke’s response to the Cambridge movement in favor of scientific research. Maxwell was called to Cambridge to become the director of the new laboratory, and he responded, knowing well that, from that moment on, most of his time would be devoted to organization and administration. Duty to his university, and to the cause of scientific research in Great Britain, stood higher in his heart than the experimental demonstration of his great theory; that was certainly one of the reasons why Maxwell did not perform those ideally simple experiments which Hertz performed. But as director of the Cavendish laboratory he had trained a number of men, in order to prepare them to push on the line of advance where he had left it; and one of them, in particular, was soon to take the leadership in the rapid development of the Faraday-Maxwell electromagnetic theory.
The examples of Henry and of Maxwell must have been in Andrew White’s mind when in 1873 he spoke those memorable words which I quoted before and will quote here again:
I will confine myself to the value, in our political progress, of the spirit and example of some of the scientific workers of our day and generation. What is the example which reveals that spirit? It is an example of zeal,... of thoroughness, of bravery,... of devotion to duty without which no scientific work can be accomplished,... of faith that truth and goodness are inseparable.
The Hertzian experiments created quite an upheaval in the research programme of the Physical Institute; everybody seemed anxious to drop his particular subject of research and try his hand at the Hertzian waves. Several candidates for the doctor’s degree yielded, but I resisted and returned to my problem in physical chemistry, and plodded along as if nothing had happened. I was very anxious to finish my research, get my doctor’s degree, and return to the United States. But I soon found out that there are currents in human life which can influence the course of life of a young scientist much more powerfully than even a new and powerful current of thought in physical sciences.
During the first two months of 1888, Nikola, the Bosnian Serb, began to look worried. He informed me confidentially that he had received bad news about the health of his great “komshiya,” the aged Kaiser. The audiences at the palace were separated by longer and longer intervals, and Habel’s long table began to look deserted; the old generals with their splendid uniforms were conspicuously absent and the historic chop-house began to look commonplace. The daily parades of the guards were finally suspended, and there were no expectant crowds in front of the Imperial palace. The gay life of Unter den Linden became very much subdued. Finally the historic event occurred: the great emperor died on March 9, 1888. Berlin went into mourning and prepared for a funeral such as Germany had never seen before. “I have secured a balcony for you and your friends right over my store,” said Nikola; “I want you and your friends to see the funeral procession as my guests.” His grief over the death of the old emperor was really pathetic. He wanted me and my American friends to see the great procession which, according to his gloomy forebodings, was to mark the first step downward in the wonderful development of the German Empire. When, consoling him, I pointed out the well-known virtues of Crown Prince Frederick, he took hold of his larynx and his gesture indicated that he expected the death of the Crown Prince from his incurable malady. “What then?” I asked him. He answered: “Ask your Bismarck and Moltke, Helmholtz and Siemens; they are your oracles, perhaps they can answer your question; no ordinary mortal can.”
Nikola had never met my American friends whom he mentioned in his invitation, but he had heard a great deal about them. My classmate at Columbia, A. V. Williams Jackson, now the distinguished Orientalist and professor at Columbia University, was at that time at the University of Halle, studying with the great Orientalist, Professor Geltner. He had visited me in Berlin and I returned his visit by spending with him a week-end at Halle. This was shortly before the great Kaiser’s death. Jackson’s mother and two sisters were there on a longer visit, and for two days I felt that I was back in New York again, and I was supremely happy. On the way back to Berlin I could not dismiss from my mind the memory of my mother’s words: “You must marry an American girl if you wish to remain an American, which I know you do.” Ever since my return from Halle, I could hear these words ringing in my ear no matter where I was, in my lodgings, in the laboratory, in the lecture-rooms, or even in Nikola’s store. Nikola had read my thoughts, and when he mentioned my American friends he meant Jackson and his mother and sisters at Halle. Well, they came, they saw, and they conquered. One of Jackson’s sisters went to Italy during that spring and I followed; she returned to Berlin to join her mother and I followed; she went to the island of Norderney, in the North Sea, to spend a part of the summer season, and I followed. The Faraday-Maxwell electromagnetic theory and the Hertzian experiments, my research in physical chemistry, and the learned essays of Helmholtz and Willard Gibbs, and of all the other fathers of physical chemistry, disappeared from my mind as if they had never been there. The only problem that could find a place there was the question: Will she accept me? She finally did, and I made a bee-line for New York, in order to find out how soon I could get a job there.
The Columbia authorities were organizing at that time a new department in the School of Mines, the Department of Electrical Engineering, and they were glad to see me and consult me about it. It was to start its work a year from that time, that is, the end of September, 1889. I was offered a position in it as “Teacher of Mathematical Physics in the Department of Electrical Engineering.” A very long title, indeed, but such it was and an interesting bit of history is attached to it. I accepted gladly and hurried back to Europe proud as a peacock. My fiancée and her family met me in London and I was married in the Greek church, according to the rites of the Orthodox faith, the faith of my mother and of all my ancestors.
“Marriage gives that fulness to life which nothing else can give,” said Helmholtz when I saw him again in Berlin and informed him that I was married and that I had been promised an academic position at Columbia College. He approved my dropping the experimental research and substituting in its place a mathematical research in physical chemistry. This research was finished in the early spring and I sent it to Helmholtz who was then in Baden-Baden. He telegraphed: “Your successful effort approved and accepted.” Never before nor since did I ever receive a telegram which made me more happy. The examinations gave me no serious trouble, and in the late spring of that year I had my doctor’s degree and became a citizen in the world of science. The three theses which, according to old German custom, every candidate seeking promotion to the dignity of a doctor of philosophy must frame and defend publicly are given here, in order to show my final mental attitude which was formulated by my scientific studies in Europe.
I. Instruction in Physics in the preparatory schools should be as much as possible a practical one.
II. The Thermodynamic methods of Gibbs, von Helmholtz, and Planck form the most reliable foundation for the study of those physical processes which we cannot analyze by ordinary dynamics.
III. The Electromagnetic Theory of Light deserves more attention than it has received so far in university lectures.
Usually these theses, appended to German doctor dissertations, are not taken very seriously either by the candidate, who is to be promoted, or by anybody else. But I took my theses very seriously. The first summed up President Barnard’s doctrine relating to scientific instruction, which I described before in connection with my description of the American movement favoring scientific research in American colleges and universities; the second summed up my admiration for the new science of physical chemistry first started by our own Josiah Willard Gibbs; and the third summed up my love for the Faraday-Maxwell electromagnetic science. On these three questions in physical science I had, I thought, quite clear and definite ideas; and that gave me much confidence that I was about to return to the United States sufficiently equipped to render service in return for some of the many favors which I had received.
As the ship which carried me back to the United States entered New York Harbor I saw on my right Castle Garden; it looked the same as it did fifteen years before, when I first entered on the immigrant ship, and it reminded me of that earlier day. I said to my bride, who was standing by my side, that I did not carry much more money into New York Harbor than I did fifteen years before, when I first looked upon Castle Garden, and yet I felt as rich as a Crœsus. I felt, I told her, that I owned the whole of the United States, because I was sure that the United States owned me; that I had an ideal American bride, who had assured me that I had lived up to the standards of an ideal American bridegroom; and that I had a fine position in a great American institution and strong hopes of filling it to everybody’s satisfaction. I enumerated all these and other things to my bride and wound up by saying, jokingly: “I have also some prospects which modesty prevents me from mentioning,” and then I added: “These are the only worldly goods with which I thee endow.”