contributed to this art as much as Faraday and Henry did. Maxwell resigned his professorship at King’s College, London, at the end of 1865, soon after he had communicated to the Royal Society his great _memoir_ on the electromagnetic theory. The electromagnetic theory of light which, as I pointed out before, he had called “great guns” in a letter addressed to a friend, was the climax of it. He retired to his country place, Glenlair, in Scotland, and for five years he was free to devote his entire time to study and meditation. That was the highest joy of his life. But the Duke of Devonshire, a loyal Cambridge man, had presented the university with a goodly sum of money for the building and equipment of a physical laboratory. It was to be named the Cavendish laboratory, after Lord Cavendish, the Duke’s illustrious ancestor, who had devoted his life to electrical science. This gift was the Duke’s response to the Cambridge movement in favor of scientific research. Maxwell was called to Cambridge to become the director of the new laboratory, and he responded, knowing well that, from that moment on, most of his time would be devoted to organization and administration. Duty to his university, and to the cause of scientific research in Great Britain, stood higher in his heart than the experimental demonstration of his great theory; that was certainly one of the reasons why Maxwell did not perform those ideally simple experiments which Hertz performed. But as director of the Cavendish laboratory he had trained a number of men, in order to prepare them to push on the line of advance where he had left it; and one of them, in particular, was soon to take the leadership in the rapid development of the Faraday-Maxwell electromagnetic theory. The examples of Henry and of Maxwell must have been in Andrew White’s mind when in 1873 he spoke those memorable words which I quoted before and will quote here again: 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_, ... of _thoroughness_, of _bravery_, ... of _devotion to duty_ without which no scientific work can be accomplished, ... of _faith_ that truth and goodness are inseparable.