Very little requires to be referred to here. The Table of Contents should render unnecessary any Index of Names. The author's connection with the subject of his book has been a lengthened one. When a mere youth in Glasgow University he joined a number of young men, among whom were representative Cana dians, Englishmen, Welshmen, and others, in forming a Literary and Philosophical Society. As a member and vice-president his contributions to it were two essays, one on Cartesianism and the other on The Relations of the Sciences. The former cost him a study of two hundred old books in Latin and French, but it soon got lost and never returned to him. The latter he still possesses, and deems on the whole fairly accurate so far as it goes. His dealing with such a subject at all he attributes to the inspiration of the greatest of his teachers, the Professor William Thom son of the time, the Lord Kelvin of to-day and of all time. My study on the Relations of the Sciences 'i'