SAY, Thomas, merchant, born in Philadelphia, Pennsylvania, 16 December, 1709" died there in 1796. His father, William Say, was an early Quaker colonist. The son was educated in the Friends' school, and learned the saddler's trade, but afterward became an apothecary. When a young man he supposed that he visited heaven in a trance. William Mentz published "The Visions of a certain Thomas Say, of the City of Philadelphia, which he saw in a Trance" (Philadelphia, 1774), on the appearance of which Say printed in the " Pennsylvania Journal" of March, 1774, the following notice" "Whereas a certain William Mentz has printed for sale, without my knowledge or consent, 'The Vision of Thomas Say, ' which is but an incorrect and imperfect part of what I propose to make public. And as I never intended what I had wrote on that head to be published (luring my life, all persons are desired not to encourage the said Mentz in such wrong proceeding." After his death his son, Dr. Benjamin Say, published an account of the vision in "A Short Compilation of the Extraordinary Life and Writings of Thomas Say, copied from his Manuscripts" (Philadelphia, 1796). He was a man of noted benevolence, a zealous promoter of education, and for many years was the treasurer of the Society for the instruction of blacks. He helped to found the Pennsylvania hospital, and was one of the founders of the House of employment.--His son, Benjamin, physician, born in Philadelphia in 1756; died there, 23 April, 1813, was educated in Quaker schools, and in 1780 received the degree of M.D. from the University of Pennsylvania. He sympathized with the colonies during the Revolution, and in 1781 he was among those known as the " fighting Quakers," who initiated the formation of the society entitled "The Monthly Meeting of Friends, railed by some Free Quakers, distinguishing us from the brethren who have disowned us." Dr. Say was well known in his profession, and in 1787 was a founder of the College of physicians of Philadelphia, whose treasurer he was from 1791 till 1809. He was a contributor to the Pennsylvania hospital, a founder of the Pennsylvania prison society (1790), and for many years the president of the Humane society. From 1808 till 1811 he served in congress. He published "Spasmodic Affections of the Eye" (Philadelphia, 1792 , and the work mentioned above (1796).--Benjamin's son, Thomas, naturalist, born in Philadelphia, Pennsylvania, 27 July, 1787; died in New Harmony, Indiana, 10 October, 1834, abandoned commercial pursuits and devoted himself to the study of natural history. In 1812 he was a founder of the Academy of natural sciences at Philadelphia, and he became a chief contributor to its journal. In 1818 Mr. Say took part in a scientific exploration of the islands and coasts of Georgia, visiting eastern Florida for the same purpose, but progress of the party to the interior was stopped by hostile Indians. In 1819-'20 he accompanied the expedition under Major Stephen It. Long to the Rocky mountains as chief geologist, and in 1823 took part in that to the sources of St. Peter's river. He removed to the New Harmony settlement with Robert Owen in 182,5, and after their separation remained there as agent of the property. His principal work is " American Entomology" (3 vols., Philadelphia, 1824-'8). His "American Conchology," seven numbers of which were published at New Harmony, was incomplete at the time of his death, His discoveries of new species of insects were supposed to have been greater than had ever been made by a single individual before. He was a frequent contributor to the " Transactions" of the American philosophical society, the New York lyceum, "American Journal of Science." and many other publications. His complete writings on the conchology of the United States were edited by William O. Birney (New York, 1858), and his writings on entomology by Dr. John L. Le Conte, with a memoir by George Ord (New York, 1859).