Stories of Great Scientists - Charles Gibson |
Kelvin and His Students
The following anecdotes have all been authenticated by old assistants or students of Lord Kelvin's, and are not included in the story merely for amusement, but to demonstrate different characteristics of our great nineteenth-century hero. Many of these anecdotes have not been published previously.
Kelvin's brain worked so quickly that it made him impatient; things could not move quickly enough for him, and one pictures him as though he were always hurrying to catch a train. On one occasion his assistant could not get him away to keep an appointment at which they were both due. A cab had been in waiting for some time, and at last the assistant got the learned Professor safely into the cab. But he was still thinking of other things, and was quite absorbed till the jog-trot motion of the easy-going horse suddenly brought him back to material things, and reminded him that they were in a hurry. Pulling down the carriage window he shouted to the coachman, "Drive quicker, I say! Drive quicker!" He then let his mind soar once more into mathematical or scientific heights, but was recalled almost immediately by the energetic manner in which the coachman was urging on the cab-horse. Down went the window again: "Don't whip that horse, I say! Don't whip that horse!
Kelvin was a great lover of animals, as the following story related by his sister, Mrs. King, will show. She tells how once when he was visiting them in Berkshire he expressed a wish to see the fine antlered deer in a neighbouring park, and they went out in search of the animals. It was evening, and the deer had settled for the night among the bracken. Some of the party were going to give a shout to rouse the deer, that they might show themselves to advantage as they bounded away; but he pleaded with his friends not to do so, "because they had just warmed the place where they were lying, and it would be a shame to disturb them." So the animals were left in peace, and the party wended their way home again.
It has been said repeatedly that Kelvin was no teacher. Some past students have said that they learnt nothing from his lectures, but on the other hand there are those who have declared that these lectures were excellent, most lucid, and most inspiring. Speaking figuratively, one might say that a great deal of the ground upon which Kelvin had to sow was not sufficiently prepared to receive the seed. With all due deference to those who gained little or nothing from his lectures, it is clear that the real students who worked at their textbooks and did not expect all the necessary knowledge to be put into their heads during the lectures received great inspiration from Lord Kelvin's teaching.
Another point worth illustrating is the fact that Kelvin really believed the average man knew far more than he did. On one occasion he called up a raw student and put a question to him, and although it was quite apparent to the class that the student knew no more of the subject than the desk in front of him, nothing would have persuaded the learned Professor of this obvious fact. Putting the question in one form after another, it resolved itself in the end to a simple "Yes!" or "No!" and when the student answered correctly in the affirmative, Kelvin quite lost his temper with him, and thumping the lecture-table he exclaimed, "Man, I knew you knew it! Why do you make me drag it out of you bit by bit?" Of course, such scenes were greatly appreciated by the other students, who could not see their fellow-student in the same charitable light as did their good-hearted Professor.
Kelvin's lectures were filled with such matter as Sir J. J. Thomson has recently described as "purple patches." He would digress from the subject with which he set out, and give a great deal of valuable information, but in some cases it would be difficult to see what really led him on to these side issues. For instance, the lecture notebook of one of his real students shows that, in a lecture on Dynamics, the Professor set out with some remarks upon Force, but very soon went off into the field of Optics, and only near the very close of the lecture got back on to the original subject, but all the time he was giving most valuable information; there was no waste of time. That he did not keep by any stereotyped plan is evident from the following incident related by one of the assistants. Suddenly entering the lecture-room on the last stroke of the bell, the Professor shouted to his assistant, "What have we to-day? What have we to-day?" And when his assistant replied that it was Optics, the Professor, evidently influenced by some thoughts that had occurred to him, probably on his way to the lecture-room, shouted, "Take it away, I say! Take it away! I'll take Dynamics!" And so the assistant had to make haste to undo all the careful work expended in fitting up the apparatus for that day's lecture, and, amidst the good-natured banter of the students, arrange the apparatus suitable for the new subject.
It was always a field-day when the ballistic-pendulum was brought out, and the assistant had an old Jacob rifle loaded and in readiness for the Professor. There was great excitement and mock alarm when Sir William took the rifle, and placing it in the grooved rests so arranged as to ensure a bull's-eye, fired at the large bob of the pendulum. The smoke had not cleared away before the Professor was at the blackboard calculating the velocity of the bullet, the assistant having shouted out the amount of displacement of the weighted pendulum.
Thomson was very original in his lecture experiments, making use of such common articles as eggs, jellies, cobbler's-wax, and all kinds of odd stuff to illustrate his remarks. In one lecture on spinning bodies he showed the difference in behaviour between a raw and a boiled egg. This was one of his well-known experiments, and on one occasion a student thought to create some confusion by substituting two eggs which he himself had brought with him in place of the two eggs prepared for the experiment and already on the lecture-table. The students waited to see the huge joke, but the learned Professor set the two eggs spinning, shouting, "Both boiled, gentlemen!" and passed on.
Another lecture appreciated by the students was one on Sound, in which Kelvin gave some demonstrations on the French horn, of which he was a master. But on the closing day of the session his lecture was more than ordinary. When the students entered they found the lecture-table covered with apparatus. The lecture began at nine in the morning, and at ten o'clock Kelvin would announce that any students requiring to attend other classes might go, but that he would continue the lecture for those who cared to wait. At eleven o'clock a similar announcement was made, and again at twelve o'clock. Messengers from his house had to return with the information that he was still lecturing. The small band who remained till one o'clock would then part after singing "Auld Lang Syne."
One peculiarity in Kelvin, and it is strange to understand, was that he did not seem to notice when a man was under the influence of intoxicants. It is well known locally that one of his assistants had a weakness in taking more refreshment than was wise. Kelvin would come into the laboratory sometimes and give this man instructions when it would have been quite apparent to any one else that the man was not capable of taking in the meaning of the instructions. The students knew this faithful old assistant's weakness, so that they thoroughly enjoyed the Professor's innocent remarks on the following occasion He was about to discourse on the diffusion of liquids, in which alcohol was one of the substances. Turning to some mixtures which had been prepared, he remarked that his assistant had made numerous experiments in the mixing of water and alcohol. Needless to say that there was a roar of laughter from the students, but the Professor thought he must have made some mistake, and when he explained that what he had meant to say was that his assistant had mixed large quantities of alcohol and water, he, of course, only added to the merriment.
There are many true anecdotes which illustrate the same point as the preceding one, and it is worth while recording one other. On this occasion the Professor had been shouting for this same assistant without any response, and when he quietly appeared in the doorway behind the lecture-table he was greeted by a voice from one of the back benches, "A gill of your best, and be quick!" but what the Professor understood of this is not stated.
On one occasion Kelvin quieted a disturbance in his class by shouting, "Gentlemen! are you schoolboys or are you philosophers?"
From the fact that Lord Kelvin sometimes did not see what the students were laughing at, one is not to suppose that he had no sense of humour. Far from it; he would sometimes make sly jokes. For instance, when the great English physicist Joule, who was one of Kelvin's staunch friends, was visiting his lordship's workshop, he came across a large coil of piano wire, and asked for what this was to be used. When Kelvin replied that it was for sounding, Joule asked: "What note?" "The deep C," said Kelvin slyly, as it was for taking soundings in the ocean. Kelvin's name is closely linked to the subject of deep-sea sounding, and in the photograph facing page 300 we see him and his brother James reading a sounding that has just been taken from Kelvin's yacht. His name is also connected very intimately with the modern forms of the mariner's compass.
Another incident which shows Kelvin's humour occurred when he was about seventy-six years of age. His secretary handed him a pen to sign a document; Kelvin was a poor writer at the best, but on this occasion he evidently made a worse scrawl than usual. Throwing the pen aside, he held the signed document from him, saying, "Look at that, it's like the writing of a man twice my age." The signature of a man one hundred and fifty-two years of age was not a bad joke.
The following little incident will serve to show two great men at play. Long before the days of cinematographs, Kelvin and Clerk Maxwell, whose life we shall consider in the following chapter, were amusing themselves with a zoetrope, or wheel-of-life, while cruising on board a yacht. Clerk Maxwell had drawn the picture of a small bridge which fell to pieces as one watched it in the instrument. He was a clever draughtsman and had ornamented the bridge with small rosettes which revolved when the zoetrope was set in motion. Kelvin noticed this and asked what made them revolve, whereupon Maxwell said he was surprised that one who was a Wrangler and a Smith's prizeman could not see that. "But what does make them revolve?" All the answer he got was, "I made them revolve for fun."
It is often stated that Kelvin made mistakes in simple multiplication upon the blackboard, much to the amusement of his students, but this statement is not quite correct. There is no doubt that he was more at home in the differential calculus than in the multiplication table, the knowledge of the latter being of a very mechanical nature; but he did not put mistakes upon the blackboard. He would turn to one of his assistants and say, "Seven times eight?" and woe to the assistant if he made a slip. Kelvin knew at once when the right answer was given. On one occasion an assistant heard him say, "Eight times nine?—A hundred and what?—No! it can't be a hundred, for ten to the power of two's a hundred."
It is difficult to realise how rapidly a mind such as that of Lord Kelvin worked. On one occasion when the author was sitting immediately behind Lord Kelvin at a special lecture, given in his own room, by Sir Oliver Lodge, we had a demonstration of lightning calculation. Lodge had remarked that the rate of electric oscillation in a particular case would be enormous, and was about to pass on, when Kelvin stated the figures, which were unthinkable. Lodge thanked the great mathematician, remarking slyly that he had no doubt the figures were correct, but he doubted if any one else could corroborate them.
As one might expect, Kelvin and his brother James had excellent memories. A good illustration of James's memory was shown only about a year before his death. The occasion was a dinner-party, and although it was previous to the days of suffragettes, the conversation turned upon the subject of a franchise for women. James referred to some ancient Greek writer's opinion of women, and Kelvin challenged his brother to quote, whereupon James recited the ode in Greek, and then translated for the benefit of the unlearned.
It is well known that Kelvin was a devout religious thinker, and never wavered from his simple statement that "all living things depend on one everlasting Creator and Ruler." Kelvin was a regular and sincere worshipper in the church of which he was a member.
Four years after the death of Margaret Crum he married Frances Anne, daughter of Charles R. Blandy, of Madeira. There were no children of either marriage. One cannot imagine a more devoted wife than Lady Kelvin, nor could her husband have exceeded his devotion to her. After Lord Kelvin's retirement they resided on their estate at Largs, on the west coast of Scotland, and it was there that his lordship died at the age of eighty-three, after three weeks' illness, which began with a chill.
By general consent the burial was in Westminster Abbey, and the funeral was attended by a multitude of scientists, not only of his fellow-countrymen, but from every continental country. His name will go down to our children's children along with that of Galileo and Newton.