Samuel Brown, a Scottish chemist and poet, born at Haddington, Feb. 23, 1817, died in Edinburgh, Sept. 20, 1856. In 1832 he en-, tered the university of Edinburgh, devoting himself chiefly to chemical studies. He began his public career in 1840 by delivering a course of lectures on the philosophy of the sciences. He early became interested in the nature of atoms and the laws of atomic action, contending that chemical substances usually considered simple are transmutable into each other. In 1843, believing that he was prepared to prove the isomerism and transmutability of carbon and silicon, he became a candidate for the chair of chemistry in the university of Edinburgh; but upon finding his proof incomplete, he withdrew. Subsequently he occupied himself with constant experiments upon his favorite subject, and at his death believed that he was on the point of a complete demonstration. In 1849 he delivered in Edinburgh a series of lectures on the history of chemistry, and in 1850 appeared his " Tragedy of Galileo." Two volumes of his essays and lectures were published in 1858, entitled "Lectures on the Atomic Theory, and Essays Scientific and Literary".