Popular Science Monthly/Volume 45/July 1894/Sketch of Heinrich Hertz
|SKETCH OF HEINRICH HERTZ.|
By HELENE BONFORT.
WHEREVER the investigating minds of scientists are at work promoting the insight of man into the mysteries of Nature, wherever friends of natural philosophy are keenly alive to the importance of this comparatively new field of study, a field in which lie some of the most essential interests of modern civilization, there will be sincere and deep regret over the death of a young professor whose splendid career came to an untimely end on the first day of this year. Prof. Heinrich Hertz, of the University of Bonn, in Germany, died on January 1, 1894, not yet thirty-seven years of age. For the last two years he had not been in good health, and, though under the treatment of his capable physicians he several times rallied and seemed to be restored to his former strength, the last winter brought a serious relapse. A chronic and painful disease of the nose spread to the neighboring Highmore's cavity and gradually led to blood-poisoning. He was conscious and in possession of his full mental power to the last; he must have been aware that recovery was hopeless, but not a word escaped his lips that would have shown to his dear ones whether hope or fear filled his heart. His wife and his mother were at his bedside for many weeks, giving him their tenderest care, and, in spite of his continuous sufferings, there were many hours of genial discourse. At such times they read to him, and he gave himself up to general topics and to matters of personal interest to them, displaying even yet his wonted brightness and cheerfulness.
Heinrich Hertz, born in Hamburg on February 22, 1857, as the eldest son of exceptionally good and clever parents. His father was, at the beginning of his career, a lawyer; in due course of time he rose to the position of judge of the Supreme Court of Appeal, and has now been for a number of years a senator of the free city of Hamburg. The childhood of Prof. Hertz was subject to every pure, healthful, and elevating influence that a highly capable father and a superior mother can exercise. Both of them gave a great part of their time to their children; their eldest boy especially enjoyed the advantage of their companionship in many a holiday's ramble through the green fields and woods, and in cozy winter nights spent in reading Homer, the German classics, and other books.
In passing through the high-school classes of his native city, his predilection for the study of natural science early asserted itself. Whenever a new course of study began and a new textbook was put into the hands of the class, the boy would devote every leisure moment to the perusal of the volume, experimenting frequently with apparatus made by himself, and never ceasing until he could tell his father, “I have mastered that book.” This statement always proved to be perfectly correct. In spite of his decided gift for natural science. Hertz chose as his vocation civil engineering. But when, after completing his studies, he came to take the first steps toward the practical execution of this design, he felt that his choice had been a mistake. His parents, with a ready perception of the deeply rooted needs of his strong and peculiar nature, whose desires they would not think of thwarting, entered into his new idea, gave him their approval, and furnished him with the necessary means. So he set out on a new course of studies in mathematics and natural science. He gave himself up to this work heart and soul, and for a number of years knew no other object in life but unceasing and unrelenting hard work. He studied physics at Munich and Berlin, and enjoyed the warm regard of Prof. Helmholtz. In 1880 he became his assistant, and, at his instigation, in 1883 settled down as a “Privatdocent,” or professor without salary at the University of Kiel. It was from this time on that he made the science of electricity the one great object of his researches, the main pursuit of his life. The first years were filled with investigations relating to electric discharges, etc. He busied himself, above all, with the new conceptions of the inner mechanism of electric phenomena, and of the connection between these and the phenomena of light and of radiant heat. These conceptions, originating with Faraday and Maxwell in England and represented in Germany by Helmholtz, were now carried forward by Prof. Hertz.
His reputation soon spread through his native country and he was in 1885 called to the Polytechnic School of Karlsruhe, which for various reasons became very dear to him. One of its attractions was the exceptionally fine and well-endowed laboratory of the institution, which furnished the most desirable facilities for unlimited experimenting. At Karlsruhe Prof. Hertz found a wife who was in every way a lovely and graceful, devoted and highly intellectual companion to him. His life was from this time on divided between the pursuit of his main object, the progress of science, and home happiness; both he and his wife derived rare gratification from literature and the beauty of Nature. It was from Karlsruhe that he went to Heidelberg, there to enjoy the proudest moment of his life, in the year 1889, when, greeted with enthusiastic applause by most prominent scientists, he stood up on the platform to tender an account of his researches and their results. Who that saw him there, the very picture of youthful vigor and life, could have foreboded that those fine and penetrating eyes, to which for the first time since our earth turned around its poles electric waves had been revealed, were so soon to be closed in death!
Soon Prof. Hertz received flattering calls to the most prominent universities; he preferred the smaller town of Bonn, where he settled down in 1890, even to Berlin, the capital, because what he sought after was the most serious and fruitful work, not glory and outward advantage. In Bonn he succeeded to the eminent physicist, Prof. Clausius; this was in itself a high distinction conferred upon so young a man as Prof. Hertz. Considered all over Europe as one of the most prominent, he was looked up to as one of the most promising leaders in the science of electricity. Not only had his own country conferred high honors upon this young and ardent worker, but the chief academies of England, France, Italy, Austria, and Russia now crowned his efforts with prizes, honorary memberships, and other tokens of universal esteem and gratitude.
Up to the middle of this century the phenomena of electricity and magnetism had been only inadequately explained by applying to them Newton's law of gravitation and asserting that, in the same way as celestial bodies exercise power of attraction at a distance and without the intervention of a medium, the two kinds of material electricity were attracting and repelling each other, while passing through space or through non-conductors.
It was the great English physicist Faraday who first sought to carry the knowledge of electricity to a higher stage, by entering upon the study of phenomena with a mind free from preconceived opinions. He put forth as the foundation on which to base new theories his observations of electric and magnetic forces, their influence upon each other, their attractions for material bodies, and their propagation by the transmission of the excitation from one point of space to another. He questioned the assumption of space being void, and conjectured that the ether which transmits the luminous waves suffers modifications perceived under the form of electrical and magnetic manifestations. His discoveries, important as they were, gained due consideration only when Faraday's great countryman, Maxwell, treated the same subject in a purely scientific and theoretical way, publishing in 1865 his Mathematical Theory of Light. The nature and properties of ether he left undecided, and they form to this day dominant questions, destined, it seems, ultimately to reveal the deepest secrets of natural science. Maxwell labored to confirm the connection, surmised by Faraday, between light, electricity, and magnetism; the idea of velocity now entered the theory and became of supreme importance. Maxwell arrived at the conclusion that the velocity of electromotion in a given medium must be identical with the velocity of light in the same medium, and that therefore ether, being contained in all ponderable bodies, would have to be looked upon as the conductor of electric motion and power. Consequently the periodical motions of ether, which our eye conceives as light, and which he figured as transversal waves, were considered by Maxwell to be at the same time undulations of electricity. These conceptions, unproved by experiment as Maxwell left them, had merely the value of a scientific hypothesis emanating from a man of rare genius. To have proved them facts, and thereby to have united two vast and highly important domains of natural philosophy, is the lasting credit of Prof. Hertz.
The complexity of phenomena of light and electricity and the insufficient opportunities afforded by the laboratory for deductions of such magnitude rendered the obstacles barring the road to exact observation well-nigh insurmountable. Many of the best and ablest naturalists were laboring to cope with these difficulties. Two English scientists of highest standing. Prof. G. F. Fitzgerald and Dr. O. T. Lodge, were during the eighties occupied with experiments for the investigation and measurement of electric waves. But it was reserved for Hertz to discover and apply with marvelous ingenuity the necessary “detector,” a resonating circuit with an air-gap, the resistance of which is broken down by well-timed impulses, so that visible sparks are produced. After an unceasing course of experiments, in which he manifested indefatigable energy and a wonderful faculty of reaching the very essence of the matter, he succeeded in deciding the questions: Is the propagation of electrical and magnetic forces instantaneous? and further: Can electrical or magnetic effects be obtained directly from light? The paper On very Rapid Electric Oscillations, which was published in 1887, was the first of a splendid series of researches which appeared in Wiedemann's Annalen between the years 1887 and 1890, and in which Hertz showed with ample experimental proof and illustration that electromagnetic actions are propagated with finite velocity through space. These twelve epoch-making papers were afterward republished—with an introductory chapter of singular interest and value, and a reprint of some observations on electric discharges made by von Bezold in 1870—under the title Untersuchungen über die Ausbreitung der elektrischen Kraft. A translation of this book, entitled Electric Waves, by D. E. Jones, B. Sc., with illustrations and a preface by Lord Kelvin, has just been published in England.
In 1889, when laying before the Congress of German Naturalists at Heidelberg the results of his labors, Prof. Hertz, with the modesty characteristic of the true investigator, the utterly unassuming disciple of science, gave ready and graceful acknowledgment to the efforts made by his predecessors or co-operators in the work, some of whom had all but attained the results which they aimed at and which he achieved. It is pleasant to recollect that when he had gained the end toward which they also had been striving, the English professors, Oliver Lodge and Fitzgerald, were foremost in announcing his success, and in preparing the English-speaking world to appreciate the importance of his discoveries. A natural bent of mind toward the questions at issue had awakened the young professor's creative powers; his complete concentration upon the vital point and his intuitive perceptions led him to definite results and complete success where so many able minds had searched in vain. In the April number of this magazine Herbert Spencer, speaking of the late Prof. Tyndall, gives a number of traits that apply with singular force and exactness to Prof. Hertz. Of these the first is “the scientific use of the imagination.” It may well be said that with this constructive imagination, as Mr. Spencer terms it, originated Prof. Hertz's rare success as a discoverer and as an instructor.
To find out the most effective arrangement of electrical conductors and to secure the conditions which would produce the strongest vibrations at regular intervals and in quickest succession, we might say the adjustment of his instruments was the first part of his work. Having brought about electric undulations up to several hundred millions in one second. Hertz proved through experiment that the waves of electricity are transversal like those of light, and that the transmission requires a certain lapse of time. He ascertained exactly the velocity of electricity; it is found by multiplying the length of wave, which he measured, by the duration of the vibration, which can be calculated, and he found this velocity to be, as Maxwell had supposed, equal to that of light, and, moreover, equal to the velocity of electric waves in metallic wires. The grand consequence of this last discovery was the cognizance of a new fact: that what had hitherto been considered as a current of electricity in a wire is really a movement along the surface of the wire. Maxwell's magnetic theory of light found further corroboration by the experimental demonstration of electric power as propagating from its center in waves similar to sound. The electric undulations are subject to the same process of reflection, refraction, absorption, etc., as the rays and waves of light, from which they are in the end distinguished only by their considerably greater length, measured sometimes by kilometres. The crowning experiments of this course finally changed what had hitherto been looked upon as a coincidence between two orders of distinct phenomena into a demonstration of identity. By gathering the electric spark in the focus of a large concave mirror, whence it came forth in the form of a rectilinear beam, the properties of the electric ray were shown to be identical with those of a luminous ray, the former producing phenomena which have heretofore been observed only in light—those of polarization. This result renders all theorizing on the matter superfluous: the identity of the two powers springs from the experiment itself; ocular proof is produced for the proposition that light is in its very essence an electrical phenomenon, whether it be the light of the sun, of a candle, or of a glowworm. Suppress electricity in the universe—light would disappear. Suppress the luminiferous ether—electric and magnetic forces would cease to act through space. Even a body not casting light can be a center of electrical action if it radiates heat. Electricity therefore possesses all Nature and even man. The eye itself is, in fact, an electrical organ.
The influence of this new system of physics upon the development of natural science and the manifold applications in practical life of which it is capable can not easily be overrated. Only recently a new application of Hertz's discovery was made by an American, who is trying to develop photographs by the agency of the Hertzian waves, as science has named them—that is, by electricity instead of light. Hertzian waves, Hertzian investigations, apparatus, and methods form henceforth an essential part of all hand and text books of electricity. The facts established by Hertz's experiments have been molded into a mathematical formula by their author, who in this purely theoretical work also has shown himself to be a master of high genius in the realm of abstract science. There is at present in press and will soon be issued by T. A. Barth, at Leipsic, a comprehensive work, Principles of Mechanics in a New Connection, found among his unpublished papers at the death of Prof. Hertz. Its appearance is eagerly watched for by the scientific world.
However highly his own time and posterity may prize the man of science, the great discoverer, in Prof. Hertz, his value as such to the world at large does not surpass that of the rare purity and greatness of his character, of the intrinsic merit which he possessed for those who knew him personally. A world-wide reputation so rapidly attained might have produced in the young man some feeling of elation and pride, and in his colleagues somewhat of envy. But, as Prof. Hubert Ludwig, representing the University of Bonn at Prof. Hertz's funeral in Hamburg, said in his memorial speech:
“The rich harvest of fame and glory which was granted him, and that was so fully merited as not to be tainted by a single breath of envy or jealousy, never caused him to give up one atom of the noble simplicity and genuine modesty which were a fundamental trait of his character. His modesty was a most lovable quality in this great man, asserting itself not only in every-day life, but also in his scientific labors, which it pervades with the endearing charm of an amiable personality. It was coupled with the most considerate indulgence when judging others. His ever-ready recognition of other people's merits made it a sheer impossibility to grudge him his attainments or to be his enemy.
|“ ‘||None knew him but to love him,|
|None named him but to praise.’|
At the same time he was governed by an inflexible veracity.”
He was indeed a most lovable man, and was never happier than in giving pleasure to others. His kindness and benevolence found expression in many ways, most of all toward those above whom he was placed as head of his department in the university. It was a pleasure to notice his satisfaction, when he found it in accordance with his duty, to confer a benefit or favor. And when it was incumbent upon him to refuse or displease, he became the director who performed his duty, and the friend who regretted what had to be done. He was always ready to show hospitality to scientific men who came to Bonn from other parts of Germany or from foreign countries. Even under the restraint of a foreign tongue (he spoke English and French with considerable fluency) his conversation was charming. Not what he had achieved, gave him his ascendency in scientific discourse, but what he, beyond a thousand learned men, could achieve at any time—original and sagacious thoughts, springing up on the spur of the moment, and losing none of their force by being expressed in the most unpretending, simple form. When entertaining friends or conversing with his dear ones, he perfectly forgot the learned professor in himself; he was so much at his ease, so full of fun, that none around him could help sharing his gayety. Many of his guests, prominent men of science as well as students, will always remember with pleasure and gratitude delightful trips made with Prof. Hertz to the Siebengebirge or evenings of genial intercourse at his house in the Quantiusstrasse at Bonn. Absolutely devoid of any desire to pose before the public, the professor sometimes astonished students newly entered for his lectures by putting in a bit of humor where they had expected abstract instruction; but they soon found themselves none the worse for it. Some simple word, a casual remark made as if it were a self -understood thing, from his lips did more toward improving the mind of his audience than a long lecture from another. He was not a scientist inculcating one special branch of knowledge—he was a thinker. To be considered an authority, even by the youngest beginner, was an idea that never entered his mind. In the congenial atmosphere of advanced classes, new ideas and conceptions seemed to rise in him and flow from his lips as though there could be no easier thing in the world. He was at his very best when propounding a problem to this small circle, showing how he would attack it. None, however capable, but could profit by this teaching; genius itself seemed to prompt it.
With penetrating perspicacity he took hold of his problems. As a veritable disciple of natural science, he strove to accomplish his ideal ends, although by means of theory, which he completely mastered, yet not merely by theory and not for her sake only; what he aimed at first and last was the most accurate establishment of facts. Pervaded as his strong personality was by an absorbing love of his science, the rare harmony of his nature kept him equally from an exaggerated enthusiasm and from prosaic dullness. An uncommonly great number of valuable researches made at the Physical Institute at Bonn during the short time of his leadership prove his rare capacity and untiring eagerness to incite young talents to the best possible application of their faculties and so pave the way for their success in research. But in a wider sense of the word we may call his disciples all those physicists who are at this moment, and will be for a long time, occupied in exploring the provinces which he was the first to open. In this sense almost one quarter of all living physicists call themselves Prof. Hertz's followers.
The honors paid at his funeral to the memory of this young and ardent worker were exceptionally great. He was buried in his native city, Hamburg, where the most widespread sympathy for his family and the deepest regret over his loss were shown. From Bonn, Karlsruhe, and Berlin came friends, colleagues, and students, some of them officially representing their colleges. Universities and prominent men from all parts of our globe have sent messages of esteem and sympathy to the wife, the parents, and the University of Bonn. It may be questioned whether such utterances of sympathy and respect, much as they tend to make mankind feel itself as one, can offer consolation to those whose bereavement is greater than words are able to convey. However, what Mr. Lowell said in one of his simple and admirable memorial addresses is certainly true:
“It may seem paradox, but the only alleviation of such grief is a sense of the greatness and costliness of the sacrifice that gave birth to it, and this sense is brought home to us by the measure in which others appreciate our loss.”
Prof. Hubert Ludwig, of Bonn, uttered the last farewell at the grave of his friend and colleague. He expressed the sentiment of those grieving at his bier in these final words:
“This loss is so great that we are tempted to recall the old saying of the envy of the gods. But in this solemn hour let us resolutely banish such temptation, and instead of rebelling against destiny, let us at the open grave of this God-inspired investigator bow low our heads and hearts before the inscrutable.”
The importance of mountaineering from a geographical point of view, as is shown by Mr. Edward Swift Balch, in a paper on Mountain Exploration read before the Geographical Club of Philadelphia, is hardly understood by people in general. How much has been done by mountaineers from a geographical, a scientific, or an artistic impulse is hardly known, and the extent of field still open for mountain exploration and observation is not really appreciated. This field, represented by the mountains and mountain ranges in the five continents and the islands, covers something like one sixth of the globe. The first undoubted ascent of a glacier-bearing peak that of the Buet, by Jean André and Guillaume de Luc, of Geneva, in 1770 was for the scientific purpose of making some experiments on the atmosphere for Jean André's book, Researches on the Modifications of the Atmosphere. The earliest ascents in central Switzerland were made by monks in the love of geographical exploration; and in the greatest of these monks, Placidus a Spescha, scientific knowledge and a love of mineralogy and geology were added to a desire to know the boundaries and the formation of the mountains with which he was immediately surrounded. Mont Blanc was first ascended, with scientific ends, by the geologist De Saussure. In the record of the contributions of mountaineering to science we have the studies of glacial phenomena and the forms of water in ice and snow and clouds, made with care and trouble by such men as Tyndall, Forbes, Agassiz, Escher von der Linth, and Guyot, who have camped out on some occasions for weeks at a time; and the famous expedition of 1842, when the movements of glaciers were practically first determined, and when the investigators from Neuchâtel lived on the ice for two seasons, under the protecting shelter of a bowlder, which became known as the “Hôtel des Neuchâtelois.” The geology of the mountains and their botany and zoology have been studied. They have been utilized for astronomical and for weather observations; and the latest important attempt in this line is M. Jannsen's establishment of an observatory on the summit of Mont Blanc.