Story Lives of Great Scientists - F. J. Rowbotham

Lord Kelvin



In 1907 Lord Kelvin was buried in Westminster Abbey, the last of six children who had played nearly eighty years before in the sunlit meadows round the College at Belfast. At this newly-established "Academical Institution" their father was teacher of Arithmetic and Geography, and the three elder children, coming home, laden with daisies and buttercups on June 26, 1824, learnt that a brother was born, the brother who became the greatest natural philosopher of his time, William Thompson, afterwards Lord Kelvin.

From a very early age he seems to have been admired and praised. When William was two years old, an artist asked his mother's permission to paint him as an angel, but he became a charming, unspoiled boy, and it was the happiest of homes till, in 1830, Mrs. Thompson died. Two years later her husband was appointed Professor of Mathematics in Glasgow University, and from their new home, overlooking the old High Street, the children could hear the "dead carts" which in that terrible year of cholera rumbled towards the Cathedral.

The two elder boys, James and William, attended their father's Junior Mathematical Class, more as listeners than as pupils; they were not intended either to sit for examination or to write the exercises, though Mrs. Elizabeth King, in her Reminiscences, relates that on one occasion, in a very large class, "not one of whom could answer a certain question," William startled everybody by calling out in his high-pitched voice: "Do, papa, let me answer!"



At another time he was heard skipping about the landing, outside his bedroom, long after the children were supposed to be fast asleep. Some problem had been set for the elder students in William's class, and determined to solve it he had gone to bed with a slate on the chair beside him. Suddenly the answer flashed on his mind, and hastily scribbling it on his slate by the light of the staircase gas, he could not refrain from shouting in triumph!

Mathematics to this twelve-year-old boy was an enthralling adventure; he never lost his zest for learning, but on winter evenings, when the slates were put away, Professor Thompson would read aloud Pope's Iliad  and Odyssey, Shakespeare's plays, Goldsmith and Sheridan, the girls sewing flannel petticoats under an aunt's supervision whilst James and William, in order that they should grow up straight and strong, lay flat on their backs, with arms extended, at his feet. William, says Mrs. King, "had the strongest sense of humour of any of them"; he was, however, "easily irritated if he were crossed, and then he became snappish a little, and we would say, 'Willie's in the crabbs, don't mind him.'"

In Glasgow College prizes were awarded by the students, not the masters: that is to say, the class were asked to vote, and William, though he was younger than James, invariably took a higher place. Not that there was ever the shadow of jealousy or suspicion between them, but very early William Thompson showed exceptional promise; in 1840 he attended the Natural Philosophy Glass, and soon afterwards entered St. Peter's College, Cambridge. In his first letter to Elizabeth he begs her to tell him how he should make coffee—whether the coffee should be put in "after or before the water was boiling"; he worked diligently and well, however, and in 1845 graduated as Second Wrangler; he also became Smith's Prizeman, and in the following year was appointed to the Chair of Natural Philosophy in the Glasgow University. He was thus fellow-professor with his father, very happy, very ambitious in the work he had set himself to do, and at his first prize-giving his students cheered the young Professor till they were hoarse. "William himself looked so young and modest," adds his sister Elizabeth, "that it was really quite touching to see him."

Grief followed closely on this first success; in 1848–49 cholera again ravaged Glasgow, and one sentence in the letter which William Thompson wrote to tell his sister of their father's death is specially worth remembrance. "I felt," he says, "that in the recollection of one so calm and so gentle and so good all clamorous, grief must be laid aside, and that the greatest honour I could pay to his beloved memory was to try to live worthy of such a father. . ."

His ideals were immensely high; not only was he a scientist, but like Humphrey Davy, he was always a poet at heart. "He uttered," says Sir Ray Lancaster, "with a delightful simplicity the thoughts, however romantic and fanciful, that bubbled up in his wonderful brain. . . . Atoms and molecules and vortices . . . were all pictured in his mind's eye, and used as counters of thought to give shape and the equivalent of tangible reality to his conceptions."

In his Cambridge days, he had already begun to ponder the molecular theory of matter, and he was bent on bringing all physical phenomena within the scope of dynamics, the science, that is to say, of matter and energy. But "our mechanical ideas and language are all derived from masses and their movement; and our chemical ideas and language mostly from molecules and their constituent atoms; there arises consequently a difficulty, inherent in the terms we use . . . when we try to explain or even describe electrons or ether. . . . Lord Kelvin's effort seems to have been to find a theory to reduce the necessary concepts to the smallest number—matter and energy. . . . In the end he found it necessary to bring in electricity as well. But who shall call this failure?"

In 1852 Thompson communicated to the Edinburgh Royal Society a brief paper laying down his famous theory of the "Dissipation of Energy". To perfect the available data for further developments, Thompson embarked upon a large number of experimental investigations which occupied much of his time for some years. He worked with Joule, who had already proved that work (e.g. friction) may be converted into heat; also that heat (e.g. steam-engine) may be converted into work; but to Thompson it occurred that the process is not reversible: it cannot go on for ever. You may, for example, easily produce heat from wood by vigorously rubbing a brass button on wood, but you cannot turn that heat back Into work. Davy and Rumford, he declared, "in concluding from their experiments that heat is a state of motion, had prepared the way for that great generalization which marks the fourth decade of the, nineteenth century as an era in Natural Philosophy. They had not made this generalization, nor quite proved that they had even imagined it. Day, when he said that the communication of heat follows the laws of the communication of motion, did not suggest the idea that in the generation of this kind of motion there may be no loss of energy by frictions and impacts as there always is in the communication of visible palpable motions. But when Rumford . . . finds that nine wax candles all burning at once generate heat as fast as a single horse working hard driving a cannon-boring machine, he gives us a reckoning in horse-power to measure the activity of a fire. And when he tells us that in no case can it be economical to keep horses for generating heat by friction, because more heat could be obtained by burning their food, he anticipates . . . Joule's discovery that the heat of combustion of a horse's food is from four to six times that obtainable through friction from a horse's work, and comes very near to that deepest part of Joule's and Mayer's philosophy in which it is concluded that animal energy and heat together make up an exact equivalent to the heat that would be generated by the chemical action in the living body if these were allowed to take place without any performance of mechanical work."

This is a long quotation; it opens up, however, a very interesting train of thought, and briefly Thompson summed up his own conclusions as follows:

  1. There is at present in the material world a universal tendency to the dissipation of energy.
  2. Any restoration  of energy, without more than an equivalent of dissipation, is impossible in inanimate material processes, and is probably never affected by means of organized matter, either endowed with vegetable matter or subjected to the will of an animated creature.
  3. Within a finite period of time past the earth must have been, and within a finite period of time to come the earth must again be, unfit for the habitation of man as at present constituted, unless operations have been or are to be performed which are impossible under the laws to which the known operations going on at present in the material world are subject.

In the same year William Thompson became engaged to Miss Margaret Crum, whom he had known from boyhood, and it is worth noticing that they were, married at Thernliebank by the Rev. Dr. Brown of Edinburgh, father of the John Brown who wrote Rab and his Friends. Hitherto, Thompson's work had been chiefly concerned with thermodynamics, "wrestling in his laboratory with the properties of matter," but in the fifties he was led towards the practical applications of Science for which he is best known to the non-scientific reader: in 1857–58 and 1865–66 he was Electrician for the Atlantic Cable.

Volta, fifty years before, had discovered the pile, "the primitive battery capable of producing a steady and continuous silent flow of electricity through the conducting wire which constituted a circuit. Oersted had discovered the power of the current to deflect a compass needle. . . . Surgeon had invented the soft-iron electro-magnet—the magnet which is controlled from a distance through the electric wire that conveys the current to it—the magnet which attracts only when the circuit is completed, and obedient to the hand of the distant operator, ceases to attract from the moment when the circuit is broken." Still more important, Faraday, by his discoveries of the "electro-magnetic rotations", had paved the way for modern electrical engineers, and in 1840 the Morse telegraph was at work in America: "based upon the attraction of an iron keeper by an electromagnet, thereby moving a lever which printed dots and dashes, or gave audible sounds in its movement." Soon there were land lines in Europe also; messages could be sent hundreds of miles, and in 1849 short submarine cables were laid: there was presently the Dover to Calais line, besides others connecting England with Ireland and Scotland, but this was as nothing compared to the two thousand miles separating Great Britain from America.

To begin with, there was the weight—to say nothing of the cost–of a cable of this enormous length, and even if it were made no single ship was capable of holding it. Also "the working speed of signalling through cables of such a length was believed to be very slow . . . a retardation arising from the charging of the surface of the gutta-percha coating by the current on its way to the distant end. . . . What retardation might be expected from a cable 2,000 miles long? Would it not so greatly reduce the speed of signalling as to make the undertaking unremunerative?"

Thompson's attention had been directed to submarine telegraphy in 1854; as the result of his calculations he insisted that in cable signalling to signal, "sent off as a short sharp sudden impulse, in being transmitted to greater and greater distances is changed in character, smoothed out into a longer-lasting impulse, which rises gradually to a maximum and then gradually dies away. Even though at the distant station the commencement of the signal may be practically instantaneous, an appreciable time may elapse for the retarded impulse to reach its maximum; and so the signal is for effective purposes retarded." Thompson was the first to show the law which governs this retardation: in proportion to the capacity and resistance of the cable, it varies, and his plan was to regulate the "time of contact with the battery". A regulated galvanic battery was therefore employed, and when it was found that for a long cable ordinary methods of registering failed, Thompson invented that most delicate of instruments, the mirror-galvanometer. An instrument was needed which would work with the smallest possible electric current, and for the heavy needle of the German galvanometer he substituted a tiny piece of steel watch-spring, cemented to the back of a glass mirror suspended by cocoon silk within the wire coil. Thompson was short-sighted, and from the eye-glass hung with a ribbon round his neck he conceived the idea of directing upon the mirror "a beam of light from a lamp, which beam, reflected on the mirror, fell upon a long white card, marked with the divisions of a scale, which was shaded from daylight, or set up in a dark corner. When, on the arrival of an electric current the suspended magnet turned to right or left it deflected the spot of light to right or left upon the scale, and so showed the signal. . . ."

Twice he accompanied the Atlantic squadron on its course; in his enthusiasm he would even have taken a turn at the wheel, if necessary, and doubtless the idea of linking Europe and America in close communication appealed strongly to his imagination.

At Windsor Castle on November 10, 1866, William Thompson was knighted by Queen Victoria; unhappily four years later his wife died, and it was long before this sorrow lifted from his life. He found time, in spite of the many varied interests of these strenuous years, to devote himself to his students. Professor Ayrton, in an article of Kelvin in the Sixties, describes him coming into his lecture-room, without a thought of what he was going to talk about. Perhaps he would give an enthusiastic account of a conversation with Peter Guthrie Tait, the friend collaborating with him in the famous Treatise of Natural Philosophy, published in 1867. Perhaps he would discuss the progress of the manuscript, but in his mathematical physics lectures his remarks were so far above the heads of most of his students that the room would gradually empty itself, and Thompson, putting up his monocle, would peer at the empty spaces, "remarking on the curious gradual diminution  of density. . . ." To those, however, who had had some training in the elements of Natural Philosophy, "his suggestions, his buoyancy, were like the rays of brilliant May sunshine following April showers."

The Treatise  sold rapidly; the contributions of the two authors seem to have acted each as a happy complement to the other, and the book was at one time actually out of print. Its object had been (a)  to give a complete review, in "language adapted to the non-mathematical reader", of what is known as Natural Philosophy, and (b)  to show those more qualified to judge, "the analytical processes by which the greater part of that knowledge has been extended into regions as yet unexplored by experiment."

In 1871, as President of the British Association, Sir William Thompson's address was awaited eagerly; he was introduced by Huxley, with whom "he had already crossed sword with knightly courtesy, indeed, but with deadly earnest, in the matter of Geological Time; and he was known to be opposed to some of the developments of the doctrines of Evolution that for a decade had been revolutionizing men's minds as to the origin of things." The address was long and discursive, but it was brilliantly interesting. Speaking of recent advances in particular branches of science, Thompson said: "Accurate measurement and minute measurement seems to the non-scientific imagination a less lofty and dignified work than looking for something new. But nearly all the grandest discoveries of science have been but the rewards of accurate measurement and patient long-continued labour in the minute shifting of numerical results." His instances were the discovery of the theory of gravitation by Newton, and Faraday's discovery of specific inductive capacity. Then he went on to speak of that branch which more particularly concerned his own labours, emphasizing the fact that science, even "in its most lofty speculations, gains in return for benefits conferred by its application to promote the social and material welfare of man". "Those who periled and lost their money in the original Atlantic Telegraph were impelled and supported by a sense of the grandeur of their enterprise, and of the worldwide benefits which must flow from its success; they, were at the same time not unmoved by the beauty of the scientific problem directly presented to them . . ." Still later in his address, Thompson said with profound significance: "I confess to being deeply impressed by the evidence put before us by Professor Huxley, and I am ready to adopt, as an article of scientific faith, true through all space and through all time, that life proceeds from life, and from nothing but life. . ." a pronouncement, by the bye, to hold in mind, when we read the story of Pasteur's war against the doctrine of Spontaneous Generation.

In 1874 Thompson married his second wife; there were, however, no children. On New Year's Day, 1892, Queen Victoria conferred on him a peerage of the realm. It was Elizabeth, the sister who has written very touchingly of his boyhood and youth, who suggested the name "Kelvin" from the Kelvin River, flowing below the Glasgow University buildings. Thompson turned impetuously to his wife: "Do you hear that? . . . That decides us; it shall be Lord Kelvin; I will write to Salisbury at once."

Lady Kelvin outlived her husband. He died in 1907, and was buried in Westminster Abbey, in the grave next to Sir Isaac Newton. His life had been a life of unceasing toil; he had gone from one effort to another, and his works live after him. But there lives also the memory of a joyous spirit which, in his own phrase, had "taken a journey far more wonderful than that of Aladdin on the enchanted carpet. . . . and the most marvellous thing about it all was that it was true."