"So, I imagine, did the capitalists of Archimedes' day. You will remember that they failed to provide him with a fulcrum," said Lord Kelvin dryly. Lord Kelvin, when a young man, became permanently lame as the result of a skating accident, but his lameness did not retard his physical activity. Sir William Ramsay, the celebrated chemist who had been a pupil of Kelvin, said that it "lent emphasis to his amusing class demonstration of 'uniform velocity' when he, Kelvin, marched back and forth behind his lecture-bench with as even a movement as his lameness would permit; and the class generally burst into enthusiastic applause when he altered his pace, and introduced them to the meaning of the word 'acceleration.'" Ramsay's opinion was that Kelvin "was not what would be called a good lecturer; he was too discursive." Ramsay doubted whether any man "with a brain so much above the ordinary, so much more rapid in action than the average, can be a first-rate teacher.... But Kelvin never allowed the interest of his students to flag. His aptness in illustration and his vigour of language prevented that. Lecturing one day on 'Couples', he explained how forces must be applied to constitute a Couple and illustrated the direction of the forces by turning around the {104} gas-bracket. This led to a discussion on the miserable quality of Glasgow coal-gas and how it might be improved. Following again the main idea, he caught hold of the door and swung it to and fro; but again his mind diverged to the difference in the structure of English and Scottish doors. We never forgot what a 'Couple' was--but the idea might have been conveyed more succinctly." Yes, and ten to one the receivers of it would have forgotten what a "Couple" was! I heard Kelvin address the Royal Society in London while he was president of that body. He had invited me to come, and I was curious enough to see the most distinguished scientific body in the world learning something from the world's most distinguished mathematician, electrician, and natural philosopher. The hall in Burlington House was filled. Had an earthquake swallowed the hall then, the world would have been deprived instantaneously of dozens of men who were doing its thinking for it. The subject of the discourse was not thrilling, nor could the lecturer have been accused of an attempt to pander to popularity. The subject was "The Homogeneous Division of Space." There shot through the hour's talk a stream of descriptive phrases such as "tetrakaidekahedronal cells", "parallelepipedal partitionings", "enantiomorphs ", and their progeny.