The following reference books are suggested for a more complete treatment of various points in the text:—Andrews' History of England. Green's Short History of the English People. Traill's Social England. Roger's A Student's History of Philosophy. Royce's The Spirit of Modern Philosophy. Huxley's Life and Letters. Smalley's Mr. Huxley, in Scribner's Magazine for October, 1905. Darwin's Life and Letters.