It is not alone among biologists, from whose standpoint it may be judged easier to reach, since they are concerned with living Nature, that we find the attitude of the lover and the artist. We find it just as well marked when the man of genius plays in what some might think the arid field of the physicist. Faraday worked in a laboratory, a simple one, indeed, but the kind of place which might be supposed fatal to the true spirit of science, and without his researches in magnetic electricity we might have missed, with or without a pang, those most practical machines of our modern life, the dynamo and the telephone. Yet Faraday had no practical ends in view; it has been possible to say of him that he investigated Nature as a poet investigates the emotions. That would not have sufficed to make him the supreme man of science he was. His biographer, Dr. Bence Jones, who knew him well, concludes that Faraday’s first great characteristic was his trust in facts, and his second his imagination. There we are brought to the roots of his nature. Only, it is important to remember, these two characteristics were not separate and distinct. In themselves they may be opposing traits; it was because in Faraday they were held together in vital tension that he became so potent an instrument of research into Nature’s secrets. Tyndall, who was his friend and fellow worker, seems to have perceived this. “The force of his imagination,” wrote Tyndall, “was enormous,”—he “rose from the smallest beginnings to the greatest ends,” from “bubbles of oxygen and nitrogen to the atmospheric envelope of the earth itself,”—but “he bridled it like a mighty rider.” Faraday himself said to the same effect: “Let the imagination go, guarding it by judgment and principles, but holding it in and directing it by experiment.” Elsewhere he has remarked that in youth he was, and he might have added that he still remained, “a very lively imaginative person and could believe in the ‘Arabian Nights’ as easily as in the ‘Encyclopædia’.” But he soon acquired almost an instinct for testing facts by experiment, for distrusting such alleged facts as he had not so tested, and for accepting all the conclusions that he had thus reached with a complete indifference to commonly accepted beliefs. (It is true he was a faithful and devout elder in the Sandemanian Church, and that is not the least fascinating trait in this fascinating man.) Tyndall has insisted on both of these aspects of Faraday’s mental activity. He had “wonderful vivacity,” he was “a man of excitable and fiery nature,” and “underneath his sweetness was the heat of a volcano.” He himself believed that there was a Celtic strain in his heredity; there was a tradition that the family came from Ireland; I cannot find that there are any Faradays, or people of any name resembling Faraday, now in Ireland, but Tyndall, being himself an Irishman, liked to believe that the tradition was sound.