volume VIII of _Nature_.
I had read Tyndall’s lectures on light before I entered Columbia College, but upon reading them again I found there very many things which I had missed before. They did not, of course, describe satisfactorily the physical properties of the luminiferous ether--no lectures ever did--but they did describe, I thought, a bit of the history of physical sciences in the United States which was a revelation to me, and was, as I know now, a most important contribution to the history of the development of scientific thought in the United States. It deserves a prominent place in this narrative, because I had been a witness of this development during the past forty years.
* * * * *
Joseph Henry, the most distinguished American physicist, together with other distinguished American scientists, among them President Barnard of Columbia College, invited Tyndall, in 1872, to deliver a course of lectures in some of the principal cities in the United States. The object of these lectures was, quoting Tyndall’s words, “to show the uses of experiment in the cultivation of natural knowledge,” hoping that this “would materially promote scientific education in this country.” Tyndall delivered his famous course of six lectures on light in Boston, New York, Philadelphia, Baltimore, and Washington. Joseph Henry, as secretary of the Smithsonian Institution and president of the National Academy of Sciences, took them under his personal direction. The success of these lectures surpassed even the most sanguine expectations. At the farewell dinner to Tyndall some of the wisest scientific intellects of the land were heard, and their words indicated clearly what was the uppermost thought in the minds of the scientific men of the United States when they invited Tyndall. I quote here some of the words spoken by these men.
President Barnard of Columbia, the first American expounder of the undulatory theory of light, said:
I say, then, that our long-established and time-honored system of liberal education ... does not tend to form original investigators of nature’s truths....
Among the great promoters of scientific progress ... how large is the number who may, in strict propriety, be said to have educated themselves? Take, for illustration, such familiar names as those of William Herschel, and Franklin, and Rumford, and Rittenhouse, and Davy, and Faraday, and Henry. Is it not evident that nature herself, to those who will follow her teachings, is a better guide to the study of her own phenomena than all the training of our schools? And is not this because nature invariably begins with the training of the observing faculties?
The moral of this experience is, that mental culture is not secured by pouring information into passive recipients; it comes from stimulating the mind to gather knowledge for itself.... If we would fit man properly to cultivate nature ... our earliest teachings must be things and not words.
Doctor John William Draper, the world-renowned American investigator of the laws of radiation from hot bodies, said:
Nowhere in the world are to be found more imposing political problems than those to be settled here; nowhere a greater need of scientific knowledge. I am not speaking of ourselves alone, but also of our Canadian friends on the other side of the St. Lawrence. We must join together in generous emulation of the best that is done in Europe.... Together we must try to refute what De Tocqueville has said about us, that communities such as ours can never have a love of pure science.
Andrew White, President of Cornell, said:
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_, zeal in search for the truth ... of _thoroughness_--of the truth sought in its wholeness ... of _bravery_, to brave all outcry and menace ... of _devotion_ to duty without which no scientific work can be accomplished ... of _faith_ that truth and goodness are inseparable.
The reverence for scientific achievement, the revelation of the high honors which are in store for those who seek for truth in science--the inevitable comparison between a life devoted to the great pure search, on the one hand, and a life devoted to place-hunting or self-grasping on the other--all these shall come to the minds of thoughtful men in lonely garrets of our cities, in remote cabins of our prairies, and thereby shall come strength and hope for higher endeavor.
Tyndall responded in part as follows:
It would be a great thing for this land of incalculable destinies to supplement its achievements in the industrial arts by those higher investigations from which our mastery over nature and over industrial art itself has been derived.... To no other country is the cultivation of science, in its highest form, of more importance than to yours. In no other country would it exert a more benign and elevating influence.... Let chairs be founded, sufficiently but not luxuriously endowed, which shall have original research for their main object and ambition.... The willingness of American citizens to throw their fortunes into the cause of public education is, as I have already stated, without parallel in my experience. Hitherto their efforts have been directed to the practical side of science.... But assuredly among your men of wealth there are those willing to listen to an appeal on higher grounds.... It is with the view of giving others the chance that I enjoyed,[I cannot find a reason for this comma, it results in a pause where there should not be one] among my noble and disinterested German teachers, that I propose, after deducting, with strict accuracy, the sums which have been actually expended on my lectures, _to devote every cent of the money which you have so generously poured in upon me to the education of young American philosophers in Germany_.
What a splendid example to the men of wealth to whom Tyndall was appealing! We shall see later that the appeal was not made in vain.
But the sentiments expressed at this dinner were echoes, only, of Tyndall’s thundering voice, to which America listened spellbound when he delivered the last of his course of six lectures on light. In the last part of this lecture, called “Summary and Conclusions,” he first erected what my mother would have called “a temple consecrated to the eternal truth” which we call light, and in that temple he placed what she would have called “the icons of the saints of the science” of light. The names of Alhazan, Vitellio, Roger Bacon, Kepler, Snellius, Newton, Thomas Young, Fresnel, Stokes, and Kirchhoff stood there like so many icons of saints which one sees on the altars of orthodox churches. In this he surpassed, I thought, even Maxwell and La Grange, and that was saying a great deal. He stood in the middle of that temple and challenged the statement once made by De Tocqueville that “the man of the North has not only experience but knowledge. He, however, does not care for science as a pleasure, and only embraces it with avidity when it leads to useful applications.” Tyndall proceeded to draw a clear distinction between science and its applications, pointing out that technical education without original investigations will “lose all force and growth, all power of reproduction,” just “as surely as a stream dwindles when the spring dies out.” “The original investigator,” said Tyndall, “constitutes the fountainhead of knowledge. It belongs to the teacher to give this knowledge the requisite form; an honorable and often difficult task. But it is a task which receives its final sanctification when the teacher himself honestly tries to add a rill to the great stream of scientific discovery. Indeed, it may be doubted whether the real life of science can be fully felt and communicated by the man who has not himself been taught by direct communion with nature. We may, it is true, have good and instructive lectures from men of ability, the whole of whose knowledge is second-hand, just as we may have good and instructive sermons from intellectually able and unregenerate men. But for that power of science which corresponds to what the Puritan fathers would call experimental religion in the heart, you must ascend to the original investigator.”
Many more passages could be quoted from Tyndall’s “Summary and Conclusions” of his American lectures. Suffice it to say here that the cause of scientific research in this country never had a more eloquent advocate than Tyndall. The message which he delivered in his American lecture tour in 1872-1873 was heard and heeded in every part of the United States and of the British Empire. It is no exaggeration to say that the response to this call was the movement for scientific research in American colleges and universities which dates from those memorable years. It was in its earliest days under the leadership of the famous Joseph Henry, President Barnard, and other American scientists who had associated themselves in the National Academy of Sciences which was chartered by an act of Congress in 1863.
I shall try to show in the course of this narrative that it was the greatest intellectual movement in the United States, producing results of which nobody could even have dreamed fifty years ago; and the end is not yet in sight.
Tyndall had called my attention to volume VIII of _Nature_. The article on Faraday I had read before, but there were a large number of other communications advocating strongly the stimulation of scientific research in colleges and universities. Tyndall’s “Summary and Conclusions” had aroused a deep interest in my mind for these things, and besides, they furnished a most welcome sidelight upon the Cambridge movement which, as described above, I had felt before I met Tyndall. The University of Cambridge was severely criticised in these communications by some Cambridge dons themselves on account of the alleged entire absence of the scientific research stimulus. One of these criticisms is so characteristic of the feeling of Cambridge in 1873 that it deserves a special reference. It is in volume VIII of _Nature_ and is entitled: “A Voice from Cambridge.” A very brief abstract follows:
It is known all over the world that science is all but dead in England. By science, of course, we mean that searching for new knowledge which is its own reward.... It is also known that science is perhaps deadest of all at our universities. Let any one compare Cambridge, for instance, with any German university; nay, with even some provincial offshoots of the University of France.... What, then, do the universities do? They perform the functions, for too many of their students, of first-grade schools merely, and that in a manner about which opinions are divided; and superadded to these is an enormous examining engine, on the most approved Chinese model, always at work....
Not even President Barnard could have uttered a more severe criticism! The most forcible appeal was made by the president of the British Association for the Advancement of Science at its meeting in Bradford, in September, 1873. This I also found in volume VIII of _Nature_. These stirring appeals were published several months after Tyndall’s lecture tour in the United States, and they all sounded to me like so many echoes of the thundering voice with which he delivered the “Summary and Conclusions” of his American lectures.
These studies, recommended by Tyndall, gave me a view of science which I did not have before. I caught a glimpse of it from the books of Maxwell and La Grange, to which I referred above. The realms of science are a strange land to a youth who enters them, just as the United States was a strange land to me when I landed at Castle Garden. Maxwell, La Grange, and Tyndall were the first to teach me how to catch the spirit of the strange land of science, and when I caught it I felt as confident as I did in Cortlandt Street after I had read and understood the early historical documents of the United States. I knew that soon I should be able to apply for citizenship in that great state called science. These were the thoughts which I carried with me when I started out for my second visit to Tyndall.
When I called on Tyndall again, a month or so after my first visit, I took along a definite plan for my future work. This pleased him, because he had advised me that every youth must think through his own head, the same advice which was given me some years later by Professor Willard Gibbs, of Yale. I assured Tyndall that my second reading of the “Summary and Conclusions,” his sixth American lecture, had cleared my vision, and that I knew perfectly what my next step should be. He was much amused when I told him how, eighteen months before, I had wandered into Cambridge like a goose into a fog, and asked me where I got that expression. I told him that it was a Serbian saying, and he looked perfectly surprised when I told him that I was a Serb by birth.
“Well, I did not decipher you as quickly as you said I did. I thought,” said he, referring to my habit of emphasizing the sound of the letter _r_ in my pronunciation, “that you were a native American of Scotch ancestry.” “Why not of Irish?” asked I, entering into his jocose mood. “Ah, my young friend,” said he, with a merry twinkle in his eye, “you are too deliberate and too cautious to suggest the Irish type. I do not know what I would have thought had I seen you when you wandered into Cambridge ‘like a goose into a fog.’”
He was evidently much impressed by my careful analysis of his “Summary and Conclusions” and of its effect upon the minds of American and English scientists. Seeing that he enjoyed informal conversation and encouraged it, I told him of my Alpine experiences in Switzerland and of the anxiety I caused to my English acquaintance because I was far from being “too deliberate and too cautious.” “Well,” said he, “I might have suspected an Irish ancestry if I had met you in Switzerland twenty months ago. But you have changed wonderfully since that time, and if you keep it up the goose that came to Cambridge may be quite a swan when it departs from Cambridge.”
I informed Tyndall that Maxwell’s glowing account of Helmholtz, which I had seen in Campbell’s life of Maxwell, and in _Nature_, to which he had referred me, had decided me to migrate from Cambridge to Berlin and take up the study of experimental physics in Helmholtz’s famous laboratory. He looked pleased, and referring good-naturedly to my goose simile again, he said jokingly: “You are no longer a goose in a fog. Let Helmholtz decide whether you are a swan or not.” Then, growing more serious, he added: “You will find in the Berlin laboratory the very things which my American and British friends and I should like to see in operation in all college and university laboratories in America and in the British Empire. In this respect the Germans have been leading the world for over forty years, and they have been splendid leaders.” This, then, was the reason, I thought, why, twelve years before, Tyndall said to his New York friends: “I propose ... to devote every cent of the money which you have so generously poured in upon me to the education of young American philosophers in Germany.”
I ventured to address to the very informal Tyndall the following informal question: “Since in your opinion I am no longer a goose in a fog, you will have no objection if I apply to the Columbia authorities to send me as their ‘young American philosopher,’ as their first Tyndall fellow, to Berlin, will you?” “No, my friend,” said he, “I have already urged you to do so. Remember, however, that a Tyndall fellow must never permit himself to wander like a goose in a fog, but must strive to carry his head high up like a swan, his body floating upon the clear waters of stored-up human knowledge, and his vision, mounted on high, searching for new communications with the spirit of eternal truth, as your mother expressed it so well.” He liked my mother’s expressions, “temple consecrated to the eternal truth,” and “the icons of the great saints of science.”
I will add here that Tyndall’s mental attitude toward science appeared to me to be the same as my mother’s mental attitude toward religion. God was the great spiritual background of her religion, and the works of the prophets and of the saints were, according to her faith, the only sources from which the human mind can draw the light which will illuminate this great spiritual background. Hence, as I said before, her fondness for and her remarkable knowledge of the words of the prophets and the lives of saints. The “eternal truth” was, according to my understanding at that time, the sacred background of Tyndall’s scientific faith, and the works of the great scientific discoverers, their lives, and their methods of inquiry into physical phenomena were the only sources from which the human mind can draw the light which will illuminate that sacred background. He nourished that faith with a religious devotion, and his appeals in the name of that faith were irresistible. His friends in America and in England, who were glad to have him as their advocate of the cause of scientific research, had the same faith that he had, and they nourished it with the same religious devotion. I know to-day, and I suspected it at that time, that this faith was kindled and kept alive in the hearts of those men both here and in the British Empire by the light of the life and of the wonderful discoveries of Michael Faraday, and by the prophetic vision which led this great scientist to his discoveries. He was their contemporary and his achievements, like a great search-light, showed them the true path of scientific progress.
My last visit to Tyndall took place toward the end of the last, that is, the Easter, term, and when I returned to Cambridge I informed my friends that at the end of the term I would migrate to Berlin. It was not necessary for me to assure them how badly I felt to leave what they often heard me call “the saints and the sacred precincts of Cambridge”; they knew of my reverence for the place and they also knew my reasons for that reverence. They understood my reverent devotion to the memory of Newton, but they did not quite understand my similar devotion to the memory of Maxwell. How could they? None of his classics were necessary in order to solve the problems usually served before the candidates for the mathematical tripos honors. Neither could they understand my admiration for La Grange, who, in their opinion, was only an imperfect interpreter of Newton. Helmholtz they appreciated more, but the exalted opinion which Maxwell had of Helmholtz had not yet penetrated among my mathematical chums at Cambridge. They were sorry to lose me, they said, but they did not envy me, because they did not see that Berlin had anything which Cambridge did not have. This never was the opinion of Maxwell and it was not at that time the opinion of Tyndall.
Tyndall was the only physicist that I had ever met who had known Faraday personally. He was Faraday’s co-worker in the Royal Institution for many years, and to him and Maxwell I owe my earliest knowledge of Faraday’s wonderful personality. Tyndall conducted me into that knowledge by word of mouth, and his conversation about Faraday’s personality and scientific temperament thrilled me. I told him that I had bought in a Cambridge second-hand book-shop three volumes of Faraday’s “Electrical Researches” for three shillings, and Tyndall remarked: “Faraday is still quite cheap at Cambridge.” Then, after some meditation, he added: “Read them; their story is just as new and as stirring to-day as it was when these volumes were first printed. They will help you much to interpret Maxwell.” He presented me with a copy of his story, “Faraday as a Discoverer,” which closes with the words:
“Just and faithful knight of God.”
In this book Tyndall drew the same picture of Faraday which Campbell had given me of Maxwell. One can imagine what it meant to the world to bring these two spiritual and intellectual giants into personal contact during the period of 1860-1865, when Maxwell was professor at King’s College, London, and Faraday was at the Royal Institution, where he had been for nearly sixty years. It was significant that at the close of that period, that is, in January, 1865, Maxwell, in a letter to an intimate friend, said this:
“I have a paper afloat, with an electromagnetic theory of light, which, till I am convinced to the contrary, I hold to be great guns.”
A very strong claim made by the most modest of men! The paper was presented during that year to the Royal Society and was “great guns.” It marks, like Newton’s discovery of the law of gravitation and his formulation of the laws of dynamics, a new epoch in science. In Maxwell I saw a Newton of the electrical science, but I confess that in those days nothing more substantial than my youthful enthusiasm justified me in that opinion. I was aware that my knowledge of Faraday’s discoveries and of Maxwell’s interpretation of them was quite hazy, and I made up my mind to get more light before I started out for Berlin.
The summer vacation was on and I decided to take Faraday’s “Electrical Researches” to Scotland, the land of Maxwell. In the preface to his great--and to me, at that time, enigmatic--electrical treatise Maxwell modestly had stated that he was an interpreter, only, of Faraday. But I was delighted when I heard Tyndall’s suggestion that Faraday would help me to interpret Maxwell. Perhaps, thought I, the invigorating air of Maxwell’s native Scotland would help me to catch some of the ideas which Maxwell had caught when he was reading Faraday. I selected what I thought would be a quiet and secluded spot, the island of Arran. It belonged to the Duke of Hamilton, and I was told that his grace had imposed so many restrictions upon his tenants that the island had become an ideal spot for those who sought seclusion. I found there a neat little inn at Corrie. It was surrounded by several tiny cottages for summer visitors who took their meals at the inn. It was popular with people from Glasgow, Greenock, and Paisley. Every one of the visiting families was blessed with numerous daughters. They were very athletic and played tennis from early morning till late in the afternoon, interrupted now and then by swimming contests in the frigid waters of the Firth of Clyde. In the evening there was lively dancing--not easy-going waltzing, but the real fling and reel of the strenuous Highland type. “What a sturdy race this is,” I said to myself, as I watched the dancers working themselves up into a frenzy of rhythmic movements, one hand resting upon the hip, the other raised high up in the air, while their joyful limbs were pumping up and down in perfect rhythm as if they were busy pulling up from mother earth all the earthly joys stored up there for mortal man. The whole scene was particularly thrilling to me when a piper came along and furnished the music. The bagpipes reminded me of my native Idvor, and made me feel at home in bonny Scotland before I had been much over a week in Arran. The Scotch and the Serbs have many things in common, and I always believed that somewhere back in the history of Iran they must have belonged to the same tribe. I am told that at the Macedonian front the Scotch and the Serbian soldiers got along beautifully, as if they had known each other from time immemorial, and they had little use for the other races assembled there. I got along at Corrie as if I had known the Scotch all my life. But that had its disadvantages also. I came to Corrie looking for seclusion where, undisturbed, I could communicate with Faraday. But the lively lassies from Glasgow, Greenock, and Paisley, the tennis and the swimming contests, the fascinating sound of the bagpipes accompanying the stirring Highland dances--all these things whispered into my ear: “Faraday can wait, but your friends here cannot.” Then I remembered a passage in one of Maxwell’s letters, given in Campbell’s life of Maxwell, which said: “Well, work is good and reading is good, but friends are better.” What a splendid excuse for joining the lassies and the lads at Corrie and revelling in the healthful pursuits of their youthful exuberance! Besides, said I to myself, have I not accomplished enough during my eighteen months’ drilling under Routh, Maxwell, La Grange, Rayleigh, Stokes, and Tyndall to deserve a complete change of mental and physical activity? When a person looks for an excuse to do what he or she likes to do a splendid excuse can always be found, and so I bade a temporary farewell to Faraday’s “Electrical Researches,” and joined the playful activities of my Corrie friends, challenging them to go the limit. In tennis and swimming I held my own, but the Highland reels floored me every time, until Madge, one of the sturdy lassies from Greenock, by persistent private instruction finally succeeded in initiating me into the mysteries of the Highland rhythm. Glen Sannox, near Corrie, with its rich bed of heather, watched me often by the hour making many futile efforts to catch this rhythm and make my limbs obey it. Nobody else watched these efforts in lonely Glen Sannox excepting Madge, and she, I told her, had more fun than a Bosnian gypsy training his bear. I can still hear the slopes of Glen Sannox echoing the clear notes of her ringing laughter, whenever I made an awkward and clumsy movement in my persistent efforts to master the Highland fling or reel. She could not help it, and I did not mind it, because I had made up my mind to do the trick or die. Finally I did it, not very well, but well enough for a fellow who was not a Scotchman, and Madge presented me with my portrait in pencil, which she drew during the intermissions between my efforts to master the art of the Highland dances. That was my reward and it was a very good one; she was a most promising young artist who had won several prizes in the Greenock art school. The memory of this experience always recalled to my mind the thoughts which went through my head at that time--the thoughts, namely, that Scotch originality, individuality, and sturdiness are hard to follow, not only when a foreigner meets these wonderful qualities in the mental activity of a Scot, like the mental activity of a Maxwell, but also in physical activity like that displayed in the national dances of Scotland. One does not appreciate fully the wonderful qualities of the Scot until he tries to master the theory and the practice of the Highland fling or reel. Maxwell’s electrical theory, I thought, might be just as different from other electrical theories as the Highland dances are different from the dances of other nations. I found out later that my guess was not very far from the truth.
Several years ago I was driving through the streets of London, visiting England again after an absence of many years. Suddenly I saw a crowd watching a Scotch dancer. The dancer was a young woman in Highland costume, and she was dancing the sword dance exquisitely; her husband was playing the bagpipes, marching up and down with all the swagger of the Scotch Highlander. I stopped my cab, got out, and watched. The memories of Corrie and Oban and of the gathering of the clans there which I witnessed while at Arran came back, and I was thrilled. Presently the dancer reached me in her tour soliciting voluntary contributions. I threw a sovereign into her plate and she looked surprised and asked me whether I had not made a mistake. “Yes,” said I, “I did make a mistake when I went out with only one sovereign in my pocket. If I had two you should have them both.” “Are you a Scotchman, sir?” she asked jokingly, and when I said “No” she smiled and said: “I did not think you were.” She knew that there was a fundamental difference between a Scot and a Serb.
After I had been at Corrie for about a month a letter arrived from my mother, written by my oldest sister, telling me how happy she was that I had decided to spend my summer in Scotland for the purpose of meditating over the life and the work of one of the greatest “saints of science.” I meant Faraday when I wrote to her. She also told me that Idvor was fearfully dusty on account of a long-continued drought, and that the crops were poor and the vintage prospects even poorer, and that Idvor was not a very cheerful place during that summer for anybody who wished to meditate free from complaints of grumbling neighbors. “Berlin, I am told, is much nearer to Idvor and when you are there you can always run down to Idvor, much more easily than you can now,” she said, closing her letter, in which logic and motherly love vied with each other to furnish her with a consolation for my absence from Idvor during that summer.
My mother’s letter made me feel guilty and it called for a reconsideration of my first resolution, adopted a month earlier, which authorized me to bid a temporary farewell to Faraday’s “Electrical Researches”; and I passed another resolution rescinding my first. But the question arose, how to carry it into effect. The answer was obvious: bid good-by to Corrie. My friends, however, suggested a less obvious but certainly a much more agreeable answer. “Go up and live in the Macmillan homestead, and read your Faraday there in the morning and come down to Corrie for dinner, late in the afternoon,” suggested Madge, and the suggestion was adopted without a dissenting voice on the part of my young friends.
The Macmillan homestead was a very humble old cottage located half-way between Corrie and the top of Goat Fell Mountain, the highest point on the island of Arran. An old crofter and his wife lived there, leading one of the most frugal existences that I had ever seen anywhere. They were willing to furnish me with lodging and simple breakfast, consisting of tea and oatmeal porridge with some bread covered with a thin layer of American lard. I did not object; I was prepared to take up low living and high thinking for the love of Michael Faraday. Communion with Faraday from early morning until four in the afternoon, and after that any play that came along, with plenty of dancing in the evening, was a splendid combination. Practically one solid meal a day, my dinner at the Corrie inn, supplied the fuel for all this activity, and it did it satisfactorily. How could I complain? The man whose wonderful scientific discoveries I was absorbing each day started life as a bookbinder’s apprentice, and the founder of the great Macmillan publishing-house was born and passed his boyhood days in the humble cottage where I was lodging. I was sure that in their youth they never had more than one solid meal a day and they prospered. My rapid absorption and digestion of the mental food which Faraday offered I attributed to my avoidance of superfluous physical food, but I must confess that I was quite hungry when dinner was served at the Corrie inn, and I enjoyed it immensely.
I never understood the full meaning of low living and high thinking as well as I did while I was a lodger at the Macmillan homestead. My thinking machinery, I thought, never worked better, and even my vision, always very good, seemed to be better than ever before. On exceptionally clear days I was sure that from the high elevation of the Macmillan cottage, on the slope of Goat Fell Mountain, I could see the beautiful Firth of Clyde as far as Greenock and Paisley, and at times even the gray and gloomy edifices of Glasgow seemed to loom up in the distance. I bragged about it, but my friends at Corrie met my bragging by informing me, jokingly, that any Scotchman can see much farther than that. One of them, a pupil of Sir William Thomson at the University of Glasgow, met my bragging by the epigrammatic question: “Can you see in Faraday as far as Maxwell, the Scotchman, saw?” I never bragged again about my vision while I was in Scotland. I was certain, however, that from the Macmillan homestead on the slopes of Goat Fell Mountain I obtained a deeper view into Faraday’s discoveries than I could have obtained in any other place. I seldom mention the names of Faraday and Maxwell without recalling to memory the beautiful island of Arran and the humble Macmillan homestead on Goat Fell Mountain.
VIII
STUDIES AT THE UNIVERSITY OF BERLIN
Every period in the history of mankind had its revelation in science. Some periods were most fortunate in this respect. The first half of the nineteenth century saw the great scientific revelation called the Principle of Conservation of Energy, and considered it its greatest glory. Our own American philosopher, Benjamin Thompson, of Woburn, Massachusetts, known in Europe as Count Rumford, was one of several early prophets in science who foresaw the advent of this great dynamical doctrine. Its importance to mankind cannot be overestimated. I am sure that many a scientific man of those days felt grateful to heaven for the blessing of having lived during the age when that great revelation was received by mankind. The scientific men of to-day are grateful for having lived during the second half of the nineteenth century, when the great electromagnetic theory was revealed to man. Its importance, likewise, cannot be overestimated. But there is a radical difference in the historical progress of these two nineteenth-century revelations in science. The existence of the first was intuitively foreseen and may be said to have existed in one form or another in the minds of many scientific men long before it received its final form of statement. Its formulator, Helmholtz, thought that he was not announcing anything new, but was only stating his own view of something that was already well known. After his announcement, in 1847, every scientific man accepted the revelation as an almost self-evident truth. The electromagnetic theory of light and of matter had a different history. It was born as a dim vision in the mind of a single man, Faraday, and nearly fifty years elapsed before it was formulated by Maxwell and experimentally demonstrated by Hertz. It was only then that the world began to understand that a great scientific revelation had appeared to man. To-day we know that new physical concepts requiring a new language for their expression had to be created in the minds of scientific men before the modern electromagnetic doctrine could be revealed to the world. The first glimpses of that revelation I caught on the slope of Goat Fell Mountain, and two years later I saw in Berlin what I believed to be a clear outline of its meaning.
When I look back to those days and consider how few were the physicists who had caught this meaning even twenty years after it was stated by Maxwell in 1865, I wonder whether it is possible to-day to convey that meaning to people who are not trained physicists. I think it is, and I believe that the attempt should be made, because the electromagnetic doctrine is to-day recognized to be the very foundation of all our knowledge of physical phenomena. I also think that one of the best methods of conveying that meaning is to describe my early attempts which failed to catch it.
Faraday’s discoveries in the electrical science during the first half of the nineteenth century attracted worldwide attention and admiration. I knew that much at Arran, and I also knew of the rapid growth of the practical applications of his discoveries, to telegraphy, to generation of electrical power for electrical lighting, electrical traction, and electrochemical work, and finally to telephonic transmission of speech. The world understood that all these wonderful things, which contributed so much to the comforts of mankind, came from those sources in the realm of abstract science which were opened up by Faraday’s discoveries. Scientific research began to assume a different aspect even in the eyes of the captains of industry who in those days showed lamentable indifference to science which did not promise immediate tangible returns. The advocates of scientific research, like Tyndall and his American and British friends, pointed with pride to Faraday’s work whenever a question arose concerning the practical value of research in the domain of the so-called abstract physical sciences. This helped very much to arouse in this country and in Great Britain a deeper interest in what Andrew White called “strength and hope for higher endeavor.”
But Tyndall’s and Maxwell’s descriptions of Faraday and of his work convinced me that Faraday’s exalted position among his contemporaries like Maxwell, Henry, Tyndall, and Barnard was due not so much to the immediate practical value of his electrical discoveries, great as that value certainly was, as it was to the clear vision with which he searched for and revealed new morsels of the _eternal truth_. It was clear to me even at that time that inventions are the handwork of mortal man and that, though at first they appeal to us, as they ought to, as wonderful creations of human ingenuity, their ultimate fate is to become more or less commonplace. The telegraph and the telephone, the dynamo and the motor, the light of the electrical arc and of the incandescent filament, had lost much of their awe-inspiring character even at the time when I was a student at Cambridge. Inventions grow old and are superseded by other inventions, and, being the creation of the constructive schemes of mortal man, are themselves mortal. But the laws which the stars and the planets obey and have always obeyed in their paths through the heavens are unchangeable; they never grow old, and therefore they are immortal; they are a part of the _eternal truth_. We do not know of any natural processes by which eternal things have been evolved. Their existence is the best philosophic proof that back of all this changeable visible world there is the unchangeable, the eternal divinity. Archimedes, Galileo, and Newton co-operated in the discovery of immutable laws, and thereby revealed to mortal man morsels of the _eternal truth_. Oerstedt, a hundred years ago, discovered a morsel of the eternal truth when he discovered the magnetic force which is produced by the motion of electricity. Discoveries of immortal things and of the immutable laws which direct the mission of their immortal existence are themselves immortal. Their discoverers are, and deserve to be, immortal. Tyndall and Maxwell were the first to show me that Faraday occupied a distinguished place among such immortals as Archimedes, Galileo, Newton, and Oerstedt.
The closing sentence of Maxwell’s biographical sketch of Faraday, in vol. VIII of _Nature_, referred to above, reads as follows:
We are probably ignorant even of the name of the science which will develop out of the materials we are now collecting, when the great philosopher next after Faraday makes his appearance.
To me these prophetic words indicated that Maxwell had something in his mind which was not explicitly expressed in Faraday’s discoveries, but which enabled Maxwell to speak like a prophet. The words of a prophet are not always easy to understand. I discovered later that, when the world with the aid of the Hertzian experiments had caught Maxwell’s meaning, then a new and wonderful epoch in the history of the physical sciences was inaugurated. Its end is not yet in sight. This inauguration I witnessed during my student days in Berlin. It is, I believe, of considerable interest to record here how the scientific world, as I saw it at that time, appeared to be preparing to receive the great revelation which was delivered to it on that historic inauguration day in 1887.
My communion with Faraday on the island of Arran began my own preparation for this inauguration day by developing gradually in my mind new physical concepts, which I discovered later to be fundamental physical concepts in the modern views of physics. Long before I had finished my reading of Faraday’s “Experimental Researches in Electricity,” I began to understand why Tyndall, referring to them, said: “Read them; their story is just as new and as stirring to-day as it was when these volumes were first printed. They will help you much to interpret Maxwell.” The same statement is true to-day, and therefore I proceed now, with much trepidation, to tell a part at least of that story as briefly as I can, in order to describe, even if it be quite inadequately, Faraday’s relation to the present great epoch of modern physics, the epoch of the electromagnetic view not only of _light_ but also of _matter_.
The gradual development of this view was due to the gradual development of new physical concepts which were born in Faraday’s mind and existed there as a poetical vision; but in Maxwell’s mind they appeared as physical quantities having definite quantitative relations to other well-known physical quantities, which a physicist can measure in his laboratory. In every creative physicist there is hidden a metaphysicist and a poet; but the physicist is less apt to persist in his occasional errors as metaphysicist and poet, because the creations of his speculative mind and of his poetical vision can be subjected to crucial experimental tests.
Faraday’s “Experimental Researches in Electricity,” published in three thick volumes, looked like very long reading. But my studies at Arran soon convinced me that no reading is long which continually stirs up the interest of the eager reader. Faraday was a pioneer in science, and the descriptions of his explorations read like tales from a new world of physical phenomena, full of poetical visions which his discoveries suggested to his imagination. It must be said, however, that in spite of his wonderful imagination and his free use of it, no investigator ever succeeded better than Faraday in drawing a sharp line of division between the new facts and principles which he had discovered and the visions which his imagination saw in the still unexplored background of his discoveries. For instance, his discovery that a perfectly definite and invariable quantity of electricity is, as we express it to-day, attached to every valency of an atom and molecule, expresses a physical law which his experiments revealed and which he illuminated with all the light of his brilliant intellect. But when this new and precious morsel of the eternal truth had been disclosed by his experiments, then Faraday the scientist stepped aside, and Faraday the poet disclosed his visions about the constitution of matter suggested by what I called at Arran the atomic distribution of electricity in material bodies.
A man who discovers one of the most remarkable facts in modern science, namely, that in every atom and molecule there are definite and equal quantities of positive and negative electricity, and that the forces between these electricities are by far the largest known forces which keep together the components of chemical structures, cannot, if he has the imagination of a discoverer, refrain from asking the question: “What is matter?” The reader of Faraday’s “Experimental Researches in Electricity” rejoices whenever Faraday, the poet and prophet, asks an apparently speculative question of this kind, because he knows that he will be thrilled by the poetical fancy which dictates Faraday’s answer. Faraday’s new facts and principles revealed by experiment are steeped in the honey of his fancy; they are rich food made delicious by the flavor of his poetical imagination, even when that flavor leaves the ordinary mortal guessing as to its exact meaning.
Two other questions Faraday often approached in these researches; they may be stated as follows: What is electricity? and, What is magnetism? He discovered that motion of magnetism produces electrical forces in a manner similar to that in which, according to Oerstedt’s discovery, motion of electricity produces magnetic forces. This remarkable reciprocal relation between electricity and magnetism stirs up the imagination, and makes it eager to look behind the curtain which separates the region of the revealed truth from that which is still unrevealed. It was undoubtedly this eagerness of the explorer which encouraged Faraday to approach the questions, What is electricity? and, What is magnetism? Faraday never gave a final answer to these questions, but his magnificent efforts to find this answer gave birth to new ideas which are the foundation of our modern electromagnetic view of physical forces. One of the great pleasures of my life has been the contemplation of the gradual unfolding of this new view; and if in the course of this simple narrative I succeed in describing some of its beauties, I shall consider that this narrative was not written in vain.
Since, as explicitly stated by Faraday, electricity and magnetism are known by the forces, only, which they exert, it was plain to him, as his books, “Experimental Researches in Electricity,” testify, that the first question which must be answered was the question: How are the forces between electrical charges and between magnetic charges transmitted through the intervening space--the same way as gravitational forces, or are they transmitted in a different way? In his unceasing efforts to answer this question Faraday made a radical and fundamental departure from the view of the natural philosophers of his time. He stood alone and devoted a very large part of his experimental work and of his philosophical thought to the justification of his position. He stood alone for a very long time, because he was formulating a radically new physical concept which the world knows now to be one of the most fundamental concepts of the electromagnetic science of to-day; and it was difficult for his contemporaries and for his students of forty years ago, including myself, to understand him. In an address on Faraday by Helmholtz, which I read during my student days in Berlin, the following sentence refers to Faraday’s difficulty just mentioned:
It is generally very difficult to define by a general statement a new abstraction, so that no misunderstandings of any kind can arise. The originator of a new concept of that kind finds, as a rule, that it is much more difficult to find out why other people do not understand him than it was to discover the new truths.
It was very consoling to me to find out in Berlin from no less an authority than Helmholtz that I was not the only poor mortal who was guessing in vain about the exact meaning of Faraday’s visions.
Newton’s law of gravitation enables the astronomers to calculate accurately from a simple mathematical formula the motion of celestial bodies, without any assumption concerning the mechanism by which gravitational force is transmitted from one body to another body at a distance, say, from the sun to the earth. Newton’s formula says nothing about the time of transmission. The action can be assumed to be direct action at a distance and therefore instantaneous. Experience seemed to indicate that this assumption is correct, because no detectable errors are committed when one assumes that gravitational force travels with infinite velocity. Faraday refused to accept this belief in direct action at a distance for electric and magnetic forces. A few words, only, will suffice to describe how Faraday attempted to eliminate the belief in this direct action at a distance for electrical and magnetic forces. These attempts will always be recorded in history as the first steps in the development of the modern electromagnetic science.
Faraday, starting from points in the electrical and in the magnetic charges, drew numerous curves which indicated at every point in space the direction of the electric or of the magnetic force, and in that manner the whole space surrounding the charges he divided geometrically into _tubular filaments which he called the lines of force_. Every one of these filaments was constructed in accordance with a simple rule, so that it indicated at every point in space not only the direction but also the intensity of the force. A specific example, often employed by me at Arran, will illustrate this. A conducting sphere, say of copper or brass, is charged with positive or with negative electricity. When that charge is in equilibrium it is, as was well known, all on the surface of the sphere and uniformly distributed. Its force of attraction or repulsion, for electrical charges in the space outside of the sphere, is obviously along radii drawn from the centre of the sphere. These radii, drawn in every direction and sufficiently numerous, envelop little cones the vertices of which are at the centre of the sphere. Adjust the size of the cones in such a way that the area of the section of every one of them with the sphere is the same, and make their total number proportional to the charge on the sphere. These little cones are then in this particular case the Faraday lines of force, because their direction gives the direction of the electrical force, and their number per unit area of the surface of any concentric sphere is proportional to the electrical force at any point of the surface of this concentric sphere. According to this picture there are attached to each little element of the total charge a definite number of these conical filaments or lines of force, and each element of the charge on the sphere is nothing more than the terminal of these filaments. When the charge on the sphere is increased or diminished the number of these filaments is also increased or diminished proportionately, and therefore they are more densely or less densely packed in the space which they occupy.
Should the charge on the sphere be set in motion, then the filaments or lines of force attached to it would also move. Thus far I followed Faraday, but went no farther; if I had gone just a little farther I should have met Maxwell. But, unfortunately for me, this simple picture which I constructed, in order to aid my understanding of Faraday’s “Experimental Researches in Electricity” over which I pondered at Arran, suggested nothing more than a mere geometrical representation of the electrical force which the charged sphere exerts at any point in space. It conveyed no additional information which a simple mathematical formula, well-known at that time, did not convey. Additional information, however, was added by Faraday’s imagination, which introduced here what I and many other mortals at that time considered a strange hypothesis. He described the hypothesis at great length in his books, and here is a brief statement of it:
Faraday claimed that all electrical and magnetic actions are transmitted from point to point along his lines of force; and, impelled by a remarkable intuition, he insisted that his lines of force are not mere geometrical pictures but that they had a real physical existence, and that there was something like muscular tension along these lines of force tending to contract them, and a pressure perpendicular to them tending to expand them; and that these tensions and pressures give the same numerical value for the mechanical force between the charges as that calculated from Coulomb’s law, but with the fundamental difference, which Faraday pointed out, that his hypothesis demands a definite finite time for the transmission of electrical and magnetic forces; whereas according to the hypothesis of direct action at a distance, which Coulomb’s law neither favors nor opposes, these forces are transmitted instantaneously. The question of the velocity of transmission of electrical and of magnetic forces through space became, therefore, a crucial question in the decision between the old view and Faraday’s view.
In a letter addressed to Maxwell in 1857, and quoted by Campbell, Faraday said:
I hope this summer to make some experiments on the time of magnetic action ... that may help the subject on. The time must probably be short as the time of light; but the greatness of the result, if affirmative, makes me not despair. Perhaps I had better have said nothing about it, for I am often long in realizing my intentions, and a failing memory is against me.
This letter was written ten years before Faraday’s death, and nothing was ever reported about the result of the experiment planned by him. We know, however, that the result which he expected from the experiment was obtained thirty years later by Hertz, a pupil of Helmholtz.
I imagined at Arran that I could hear Faraday say:
Where the lines of magnetic force are there is magnetism, and where the lines of electric force are there is electricity.
Faraday’s answer to the questions, “What is electricity?” and, “What is magnetism?” was, therefore, according to my understanding at that time, that they were manifestations of force; and where these manifestations exist there is electricity and there is magnetism, in the sense that there are pressures and tensions which are the result of a certain state of the space which may be called the electrical or the magnetic state. Faraday’s visions, as I found them nearly forty years ago, disclosed in his “Experimental Researches in Electricity,” went even so far as to suggest that matter itself consists of centres of force with lines of force proceeding from these centres in every direction to infinite distances, and where these lines are there is the body; in other words, every material body, like every electrical and every magnetic charge, extends to infinity by means of its lines of force; and hence all material bodies are in contact, explicitly denying the existence of ether. No mortal man ever suggested a bolder conception! And yet to-day we know that a conception regarding the structure of matter very similar to that first conceived by Faraday is rapidly gaining universal recognition, not merely as a new metaphysical speculation but as the logical and inexorable demand of experiment. But when Faraday told me all these strange things as I listened attentively on the slope of Goat Fell Mountain at Arran, I could not see anything in them except geometrical pictures and a lot of what appeared to me like pure metaphysics in the background of simple geometrical structures. Although I was sure that Faraday’s metaphysics had some definite physics back of it, I was unable to disentangle it from the hypothetical notions which I did not understand clearly. Maxwell, I thought, must have disentangled that physics, and I often thought of my Scotch friend at Arran who asked me the question: “Can you see in Faraday as far as Maxwell, the Scotchman, saw?”
When I came to Berlin my head was full of Faraday’s lines of force starting at electrical and magnetic charges and winding in all sorts of shapes through space, like stream lines which start from the sources of a river and follow it in its flow toward the ocean. The physical facts and principles which Faraday discovered stood out sharply defined like the bright stars in the firmament of a clear and quiescent summer night; but the conception of the new view of attracting and repelling electric and magnetic forces, which he represented graphically by his lines of force, endowed with strange physical powers residing in pressures and tensions, left in my mind impressions which made me feel that my faith in the new doctrine was not very strong. Faith without conviction is a house built upon sand. Helmholtz said once:
I know too well how often I sat staring hopelessly at his descriptions of the lines of force, their number and their tensions.
Little I thought during my journey from Arran to Berlin in October, 1885, that two years later all the nebulous notions in my perplexed mind would lift like the mist before the early rays of a sunny autumn morning. I continued my studies of Faraday during my first year in Berlin, reserving for that purpose the necessary time for extra reading. What did the physicists of Berlin think, I wondered, of Faraday’s tubes or lines of force?
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.
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.
Helmholtz was rather reserved and could not easily be approached by his students, unless they had some physical problem or a question which was unquestionably worthy of his attention. I made up my mind to ask him, when suitable opportunity presented itself, why Kirchhoff in his lectures paid so little attention to Faraday and Maxwell. It was a very significant sign of those days and I did not understand its meaning. Professor Koenig threw up his hands in holy horror when I informed him of my intention, and prophesied that all kinds of dire consequences would result from my daring proposition; pointing out that such a question would betray a lack of respect on my part both for Kirchhoff and for Helmholtz. Koenig himself could not answer my question except to say that he did not see why the German school of physics should worry much about the English school, particularly when there was a radical difference between the two in the realm of the theory of electromagnetic phenomena. I admitted that if Kirchhoff was the spokesman of the German school then there was a radical difference, intimating however, in the mildest possible way that, in my humble opinion, the difference counted in favor of the English school. I really did not know enough to express that opinion, but I did it under provocation. Koenig flushed up and there would have been quite a lively verbal contest if Helmholtz had not entered my room at that very moment, like a _deus ex machina_. He was making his customary round of visits to the rooms of his research students, in order to find out how their work was moving along. Both Koenig and I looked somewhat perplexed, betraying the fact that we had been engaged in a heated argument, and Helmholtz noticed it. We confessed that we had had a lively discussion; when he learned the subject of our discussion he smiled and referred us both to an address which he had delivered before the Chemical Society of London, five years before. It is entitled, “Recent Developments in Faraday’s Ideas Concerning Electricity.” The same day saw me with two volumes of Helmholtz’s addresses in my hands analyzing his Faraday address. I felt as I went on with this study as if the heavy mist were lifting which had prevented me from seeing a clear view of Faraday’s and Maxwell’s ideas. Tyndall’s fame for clearing up obscure points in physical science was deservedly great, but when I compared Helmholtz’s interpretation of Faraday and Maxwell with that which Tyndall gave me in his book entitled “Faraday as Discoverer,” I marvelled at Helmholtz’s superiority. It must also be remembered that Tyndall was for many years in almost daily contact with Faraday; and, as I pointed out before, he must also have had close personal relations with Maxwell during the period of 1860-1865. To me it seemed a miracle that Helmholtz, a German, saw so much more clearly what was in the minds of two great English philosophers, although he never had met them personally, than did another great English physicist, Tyndall, who knew Faraday and Maxwell personally, and one of them at least intimately. In the article in _Nature_, to which Tyndall first referred me and which Maxwell had written, will be found the following closing paragraph:
Helmholtz is now in Berlin, directing the labors of able men of science in his splendid laboratory. Let us hope that from his present position he will again take a comprehensive view of the waves and ripples of our intellectual progress, and give us from time to time his idea of the meaning of it all.
Helmholtz’s address on Faraday was one of those comprehensive views of which Maxwell spoke in 1874. Now what did Helmholtz see in Faraday and Maxwell which other physicists, like Tyndall, and even so famous a mathematical physicist as Kirchhoff, failed to see? It was, I thought after a careful study of Helmholtz’s address, the simplest thing in the world, particularly for one who, like myself, had been wrestling with Faraday’s lines of force, and with the hypothetical powers with which Faraday had endowed them. So simple, indeed, that I venture to describe it here. But in order to make the description as brief and as simple as possible I must go back again to the charged spherical conductor which always rendered good service in those days when I was trying to solve the riddle of Faraday’s new physical concepts.
By means of an electrical force generated by an electrical machine we can increase or diminish the charge on the surface of the conducting sphere. Now, the charge on the sphere increases or diminishes because the electrical force generated by the machine drives through a suitable conducting wire additional electrical charge to the sphere, or takes it away from it. This motion of the electrical charge through the conducting wire to or from the sphere is the electrical current. Here comes now the historic question: Does the electrical current stop at the surface of the charged sphere? The old electrical theories said “Yes,” but Maxwell, interpreting the ideas of Faraday, said, “No.” Helmholtz was the first to tell me that clearly and distinctly, and I understood him.
Since, according to Faraday, each particle of the charge on the sphere carries attached to it a definite number of filaments or lines of force, it is obvious that the rate at which the charge on the sphere increases is, as I described above, the same as the rate at which the number of these lines of force are crowded into the space surrounding the sphere. Motion of the charge to the surface of the sphere is accompanied by a motion of the Faraday lines of force through every surface which surrounds the charged sphere. Since, according to Faraday, electricity is everywhere where the lines of force are, it follows that the motion of the lines through any surface means motion of electricity (in the sense in which I use this word) through that surface. Maxwell said, according to my understanding of Helmholtz, that motion of electricity, as represented by the motion of Faraday’s lines of force, is an electrical current just as much as the motion of electrical charges is. Electrical charges are terminals, only, of the lines of force; and why should the motion of the terminals be endowed with a power which is denied to the remaining parts of the lines of force? The principal power is, according to Oerstedt’s discovery, the generation of magnetism; that is, magnetic lines of force. According to Maxwell, then, the electrical current (that is, the motion of electrical charges through conductors) does not stop at the surface of the conductor, but continues in the non-conducting space beyond as motion of Faraday’s lines of force, as _motion of electricity_. The extension of the meaning of the word electrical current, just described, was, according to Helmholtz, the cardinal difference between the old electrical theories and the Faraday-Maxwell electromagnetic theory, and Helmholtz declared in favor of the last. I applauded Helmholtz and took off my hat to his clear vision of things which other people, including myself, failed to see. But can any one blame ordinary mortals, who were always accustomed to look upon the electrical current as motion of electrical charges in conductors, when they failed to see that the electrical current can take place even in a vacuum where there are no electrical charges at all, and therefore no motion of them? That was the physical concept which found its way so slowly into minds polarized by preconceived notions even after Helmholtz’s lucid explanation. This is substantially all there is in the Faraday-Maxwell electromagnetic theory as I gathered it directly from the Helmholtz address. But there is another very important element which I ought to describe here.
A corollary of Maxwell’s extension of the meaning of electrical current, which Helmholtz did not mention explicitly but which I soon found in Maxwell, is this: Electrical charges move because a force acts upon them; similarly the number of Faraday’s lines of force, passing through any surface in space, increases or diminishes because there is a force acting upon them. Wherever there is an action there is an equal and opposite reaction, according to the most fundamental law of Newton’s dynamics. Hence space, including the vacuum, must react when Faraday’s lines of force (that is, when the electricity represented by them) move through it. But if this reaction really exists in space, how can it be expressed? Faraday and Maxwell devoted much thought and many experimental investigations in search for a definite answer to this question, and they found it.
Faraday showed by experiment that if the charged sphere is immersed in an insulating fluid, say an insulating mineral oil, or in a solid insulator like rubber, or even if a piece of an insulator is brought near it, then the reacting force for a given charge on the sphere is smaller than when the sphere is surrounded by a vacuum; or, in other words, liquid and solid insulators are more _permeable_ to the electrical lines of force (that is, to electricity) than a vacuum is. Therefore, an electrical force which is acting in order to increase the charge on the sphere and, as a result, increase the number of lines of force through the surrounding space, will experience the less reaction the more permeable the surrounding medium is. The reaction of an insulator against the action of an electrical force appears therefore as a reaction against the passage of electricity, that is, of electrical lines of force, through it. That picture of the process has stayed with me ever since my Berlin days.
The same line of reasoning which I followed above, regarding electrical lines of force, leads to similar results with regard to the magnetic lines of force. The reaction of the medium against an increase of the electrical and of the magnetic lines of force through it was the second new physical concept introduced into the electrical science by Faraday and Maxwell.
The Faraday-Maxwell electromagnetic theory extended the well-known electrical and magnetic actions and reactions from conductors to non-conductors, including the vacuum. If this theory is correct, then electromagnetic disturbances will be propagated from their source to all parts of space, and not along conductors only, by definite waves travelling at a definite velocity.
Maxwell’s calculation showed that electromagnetic disturbances are propagated through insulators in the same manner as light is propagated, and that, therefore, _light is in all probability an electromagnetic disturbance_. This is the substance of Maxwell’s electromagnetic theory of light; it is his answer to the question: “What is Light?”
That, broadly stated, was the information which Helmholtz first conveyed to me in terms which I understood clearly; and for this service I have always been profoundly grateful to him. He showed me that the Faraday-Maxwell electromagnetic theory was incomparably simpler than I thought it to be, and also much more beautiful. I do not believe that in 1881 there was another physicist in continental Europe who could have given me that information, and perhaps not even in 1886, when I first read that wonderful address. My friend Niven in Cambridge, editor of the second edition of Maxwell’s great mathematical treatise, never volunteered to tell me how Maxwell answered the question: “What is Light?” Neither did Tyndall. I do not know whether Rayleigh or Stokes or anybody else in Cambridge when I was there could have done it as well as Helmholtz did. I shall describe later an historical event which indicates that they probably could not.
Toward the end of that semester I felt certain that I understood Helmholtz’s interpretation of Faraday, and of Maxwell’s answer to the question: “What is Light?” I then managed to have another discussion with Professor Koenig. He listened most attentively to my description of the Faraday-Maxwell electromagnetic theory as I had gathered it from Helmholtz; and it was, as far as I can recall it now, very similar to the description given above. This was my first lecture at the University of Berlin, delivered to a very intelligent audience of one person, dear little Doctor Koenig. It would have been a signal success if I had not closed it with a tactless remark, to the effect that Helmholtz, in his Faraday address, rejected every one of the four German electrical theories, and declared himself in favor of Faraday and Maxwell. Helmholtz intimated, and unfortunately I did not hesitate to say so to Doctor Koenig, that physicists of continental Europe had not accepted the English theory because it was above their heads. Finally I said that all this explained most satisfactorily why Kirchhoff paid so little attention to Faraday and Maxwell. Koenig looked at his watch, and, as if suddenly remembering an important engagement, he turned on his heels and left without his customary bow and greeting. His national pride was evidently wounded. I regretted it deeply. I did my best to make up with him and succeeded finally, by admitting unreservedly that, after all, the Faraday-Maxwell electromagnetic theory rested upon several bold assumptions which had not yet been verified by experiment. The German electrical theories also rested upon unverified assumptions, but I said nothing about that for fear of endangering the re-established _entente cordiale_ between Doctor Koenig and myself.
Excellenz von Helmholtz had left Berlin for his summer vacation; among my German fellow students at the Physical Institute there was not much interest in Faraday and Maxwell. I do not know how difficult it is to conceal a deep secret, because I never had one to conceal; but I do know how hard it is to keep imprisoned in one’s heart the joy which one feels when the light of new knowledge rises above one’s mental horizon. I had planned to visit my mother during that summer; I had not seen her for nearly two years. Perhaps, I thought, I might find somebody in my native Banat to whom I could disclose the joy which I received from the revelation which came to me through Helmholtz. Kos, my teacher of fifteen years before in Panchevo, was no longer among the living; in fact, that school was no longer in existence, the Hungarian régime having replaced it by a Hungarian school. I would have liked nothing better than to tell him how Maxwell answered the question: “What is Light?”
* * * * *
In the beginning of August of that summer I was in Idvor again, carrying with me the two volumes of Helmholtz’s addresses. My mother received me with a heart which she described as overflowing with blessings which my visit and the visit of God’s grace upon Idvor was pouring into it. The golden harvest was all in, and it was the richest that Idvor had seen for many a year; the grapes in the old vineyards were beginning to ripen, and the peach-trees among the rows of vines in the vineyards were heavily loaded with the juicy fruit of ambrosial flavor; the melons in the endless melon patches looked big and flourishing, and suggested that at any moment they might burst with the fulness of their exuberant prosperity. The dark-green corn-fields seemed to groan under the heavy load of the young ears of corn, and the pasturelands alongside of the corn-fields were alive with flocks of sheep, carrying udders which reminded one of the abundance of milk, cream, and cheese such as Idvor had seldom seen. All these things my mother pointed out to me, and she assured me that by the grace of God she was enabled to be a bountiful hostess to me, because she had everything in great abundance which she knew I always liked. Melons, cooled at the bottom of a deep well; grapes and peaches picked before sunrise and covered up with vine-leaves to keep them cool and fresh; young corn picked late in the afternoon and roasted in the evening in front of a wood fire; cream from sheep’s milk supplied by the blessed sheep the day before. All these were sweet and delicious things; but have you ever tasted them when their sweetness is flavored by the love of an indulgent mother? If you have not, then you do not know what sweetness is. I warned my mother that her hospitality might transform me, as three years before, into a pampered pet who would be too slow to return to Berlin. Reminding me of the story which she had told me two years before, describing my climb up the steep and slippery roof of Bukovala’s mill in search of a star, she said: “You have done much climbing during the last two years, and I know that in your climbing you have found several real stars from heaven. One of them is now in Berlin and no sweets in Idvor will keep you away from it.” She guessed right, undoubtedly because she observed with what joy I kept up, during that vacation, my reading of Helmholtz’s addresses.
Many a night during that summer I spent in my mother’s vineyard sleeping on sheepskins under the open sky and looking at the stars at which I looked fifteen years before, when I helped the herdsman to guard the village oxen during the starlit summer nights. I remembered the puzzles which I tried to solve at that time concerning the nature of sound and of light, succeeding in the case of sound and failing in the case of light. I rejoiced at the feeling that I had finally succeeded in finding from Faraday and Maxwell through Helmholtz that sound and light resembled each other, one being a vibration of matter, and the other a vibration of electricity. The fact that I did not know what electricity is did not disturb me, because I did not know what matter is. Nobody knows the exact nature of these even to-day, except, as Faraday suggested, that they are manifestations of force. David’s nineteenth Psalm, which I recited so often fifteen years before during my training in herdsmanship, conveyed a different meaning, and so did Lyermontoff’s line which says that “star speaketh to star.” They certainly spoke to me during those glorious August nights, when, covered with sheepskins, I lay in my mother’s vineyard and amid the deep silence of slumbering earth I listened to their heavenly tales. The more I listened the more I became reconciled to the idea that the language of the stars reaches me in the same way that human language does, when it speeds on over the telephone wire, conveyed by vibratory electric and magnetic forces; except that in the transmission of the telephonic message the vibratory forces glide along the conducting wire, whereas the stars pour out their waves of vibratory electromagnetic forces in ever-expanding spheres so that they may carry the heavenly message to every other star and to everything that lives, and to everything that has a being. I could not help telling my mother of my new knowledge which persuaded me that light is a vibration of electricity, very much like the vibration of the melodious string described in the Serbian figure of speech, familiar to her, which says:
My heart quivers like the melodious string under the guslar’s bow.
She always was the most attentive audience that I ever had, and the most responsive. Her wonderful memory, even at that time when she was seventy years of age, assigned to every essential event of her experience a suitable place, so that it became a vital chord in the symphony of her life. She never heard anything worth hearing without responding with one of these harmonious chords, and this was particularly true when I was speaking to her. On this particular occasion, referring to my new knowledge which I brought to Idvor from Berlin, she reminded me of my new knowledge about lightning which I had acquired from my teacher Kos, in Panchevo, some fifteen years before, and afterward tried to explain it to my father and his peasant friends, who accused me of heresy; and she recalled her defense of me. She suggested, jokingly, that if my father and his old friends had still been living they would perhaps accuse me again of heresy on account of some old legends which clashed with my new knowledge; and she assured me that she would defend me again. “God sends sunlight,” she said, “to melt the ice and snow of the early spring, and to resurrect from death everything that lay lifeless in the cold grave of the bosom of mother earth, chilled by the icy breath of winter. The same sunlight,” she continued, “awakens the fields, the meadows, and the pasturelands, and bids them raise the daily bread of man and beast; it also ripens the honey-hearted fruit in orchards and vineyards. If that is all done by the same heavenly force which hurls the lightning across the sombre summer clouds pregnant with showers, and also carries, as you say, the humble human voice over the wires between distant peoples, then I see in it a new proof of God’s infinite wisdom which uses one means only to do great things as well as small. Ko che ko Bog! Who can fathom the power of God!” I reminded her of her saying which she often addressed to me when I was a boy and which I quoted before, namely: “Knowledge is the golden ladder over which we climb to heaven,” and asked her whether she included in this the knowledge which I was describing to her.
“I include every knowledge,” she said, “which brings me nearer to God; and this new knowledge certainly does. Just think of it, my son: God has been sending his messages from star to star and, according to David, from the stars to man, ever since the creation of Adam, employing the very same method and means which man, imitating the divine method, is beginning to use when he employs electricity to carry his message to a distant friend. Your teachers who gave you that knowledge are as wise as the prophets and as holy as the holiest saints in heaven.”
When I told her of Faraday’s vision, that all things extend to and exist in every spot of the universe at the same time and that, therefore, all things are in perpetual contact with each other, every star feeling, so to speak, the heart-beat of every other star and of every living thing, even of the tiniest little worm in the earth, she answered:
“Faraday’s science is that part of my religion which is described in the words addressed to God by King David:
“‘Whither shall I go from thy spirit? Or whither shall I flee from thy presence?
“‘If I ascend up into heaven, thou art there: if I make my bed in hell, behold, thou art there.’
God is everywhere, and where he is, there is every part of his creation.” Her religion taught her how to catch the spirit of science, and I was always certain that science can teach us how to catch the spirit of her religion.
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.
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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