Lardner, Dionysius LL.D., a distinguished English writer on physical science, was born in Dublin April 3, 1793, and was appointed professor of natural philosophy and astronomy in University College, London, in 1828. In 1830 he projected a sort of Encyclopaedia, consisting of original treatises on history, science, economics, etc., by the most eminent authors, and 134 volumes were accordingly published, under the general name of Lardner's Cyclopaedia, between 1830 and 1844. Some of these volumes were from his own pen. A second issue of this work was begun in 1853. He has published various scientific works, the most important of which are his "hand-books" of various branches of natural philosophy (1854-56). He is also the author of the Museum of Science and Art, an excellent popular exposition of the physical sciences, with their applications. He died in Paris April 29, 1859.