Faraday’s enthusiasm about experimental researches was at times unrestrained, and always contagious. Dumas describes how Faraday repeated for him the experimental demonstration of the action of magnetism on light. Having come to the final experiment, Faraday rubbed his hands excitedly, while his eyes lit up with fire, and his animated countenance told the passionate feelings which he brought to the discovery of scientific truth. On another occasion Plücker, of Bonn, then on a visit to London, showed Faraday in his own laboratory the action of a magnet upon the luminous electric discharge in vacuum tubes. “Faraday danced round them; and as he saw the moving arches of light, he cried: ‘Oh, to live always in it!’” Once a friend met him at Eastbourne in the midst of a tremendous storm, rubbing his hands together gleefully because he had been fortunate enough to see the lightning strike the church tower. To the Baroness Burdett-Coutts he once wrote inviting her to see some experiments upon spectrum analysis in his private room. _The experiments_, he wrote, _will not be beautiful except to the intelligent_. Yet another reminiscence is to be found in the Memorials of Joseph Henry. It relates, probably, to the date of 1837, when Henry visited Europe. Henry loved to dwell on the hours that he and Bache had spent in Faraday’s society. I shall never forget Henry’s account of his visit to King’s College, London, where Faraday, Wheatstone, Daniell, and he had met to try and evolve the electric spark from the thermopile. Each in turn attempted it and failed. Then came Henry’s turn. He succeeded, calling in the aid of his discovery of the effect of a long interpolar wire wrapped around a piece of soft iron. Faraday became as wild as a boy, and, jumping up, shouted: “Hurrah for the Yankee experiment!” The following memorandum was found on a slip of paper in Faraday’s “research drawer”:-- THE FOUR DEGREES. The discoverer of a fact. The reconciling of it to known principles. Discovery of a fact not reconcilable. He who refers all to still more general principles. M.F. [Sidenote: FREEDOM OF SPECULATION.]