have already referred to this in my short allusion to the Cambridge craving for scientific research, and I shall now attempt to describe a much wider intellectual movement of which this craving was a local manifestation only. I felt the force of its current during my Cambridge days, and I recognize to-day that at that time I moved along following more or less unconsciously the stream-lines of this current. The completion of the mathematical training under Routh recommended by Niven was approaching its end, and I was satisfied with its results. I could follow without much effort the lectures of Stokes and Lord Rayleigh, and I could handle the mathematics of Maxwell’s theory of electricity with considerable ease; but I did not understand his physics. President Barnard, of Columbia College, said once in an address of fifty years ago that a young student in America at that time lacked a “knowledge of visible things and not information about them--knowledge acquired by the learner’s own conscious efforts, not crammed into his mind in set forms of words out of books.” His statement fitted admirably my own case; I lacked that knowledge of visible things which one gets from his own conscious efforts; I had no knowledge of physics acquired from my own conscious efforts in a physical laboratory. Neither Columbia College nor any other college in the United States, with very few exceptions, offered at that time this opportunity to the student. I suspected that this was the real secret of my inability to understand Maxwell’s physics; I longed for work in a real physical laboratory and made preparations to enter the Cavendish Laboratory at Cambridge. But I learned, in the beginning of 1885, that Lord Rayleigh had given up the directorship of this laboratory, and that a Mr. J.J. Thomson of Trinity College had been appointed as his successor, the same Thomson who is to-day Sir John Joseph Thomson, Master of Trinity College, and the leading physicist in the world. The new director was only twenty-eight years of age in the year of his appointment--at the end of 1884. Although a second wrangler in the mathematical tripos test of 1880, he was four years later already a sufficiently famous experimental physicist to be appointed director of the Cavendish Laboratory. The new director was only two years older than myself, but he was already a famous experimental physicist, whereas I had never had a physical apparatus in my hand. What will he think of me, thought I, when I present myself to him and ask for permission to work as a mere beginner in the Cavendish Laboratory! I blushed when I thought of it, and I was afraid that I should blush even more when he compared me to his younger students who had already acquired much skill in physical manipulations. The failure of my competition with boys and girls in the speed tests of punching biscuits in the Cortlandt Street cracker factory came back to my memory; and I bemoaned, just as I did