"No biographer who agreed with Horsley could have given us anything so valuable, so convincing, so vitally defined.... Mr. Paget has never had an equal as a medical biographer, and here he has excelled himself."--_The Observer._ LIFE AND LETTERS OF JOSEPH BLACK, M.D. By Sir WILLIAM RAMSAY, K.C.B., LL.D., F.R.S., etc. Introduction by F. G. DONNAN, F.R.S. Demy 8vo. Frontispiece Portrait and Illustrations. 6s. 6d. net. ROBERT BOYLE: A Biography. By FLORA MASSON. Frontispiece. Demy 8vo. 7s. 6d. net. "May be recommended as an excellent study of the great Irishman to whose services as natural philosopher and chemist even modern scientists owe a debt of gratitude."--_Pall Mall Gazette._ THE LIFE OF SIR CHARLES TILSTON BRIGHT. By CHARLES BRIGHT, F.R.S.E. Revised and Abridged. Illustrations. Demy 8vo. 12s. 6d. net. "The life story of Sir Charles Bright presents the career of a famous Englishman with all the charm of simplicity and enthusiasm.... As the chief engineer of the Atlantic cable Sir Charles Bright will always have a memorable place in the scientific progress of this century.... These volumes possess a special interest for men of science, but they tell with clearness and simplicity the career of a man of whom Englishmen must always feel proud."--_Morning Post_. [_Spring 1921._] MESSRS. CONSTABLE will be glad to send free on application classified Lists of their publications. The following subject headings are ready:-- POLITICS, POLITICAL SCIENCE, AND SOCIOLOGY. HISTORY. WAR AND MILITARY HISTORY. RELIGION AND PHILOSOPHY. EDUCATION AND PSYCHOLOGY. ECONOMICS AND COMMERCE. ART AND ILLUSTRATED BOOKS. FICTION. _Please write to_ 10-12 ORANGE STREET LONDON W.C.2. * * * * * * Transcriber's note: Variations in spelling and hyphenation have been retained except in obvious cases of typographical error. Names and terms which deviated between chapter headings and text have been made consistent.