ALEXANDER BAIN, one of the best representatives of the later school of Scotch scientific essayists, was born at Aberdeen in 1818. He became Examiner in Logic and Moral Philosophy for the University of London in 1857, and in 1860 Professor of Logic in Aberdeen University, of which in 1881 he became Lord Rector. His style is so clear and his language so free from technicalities that his scientific essays have been widely popular in the United States, as well as in England. He has written much on the same general lines with Herbert Spencer; but he is an original thinker of great power, and it cannot be said with justice that he has followed Spencer or any one else.