Thomas Sterry Hunt, an American chemist, mineralogist, and geologist, born in Norwich, Conn., Sept. 5,1826. He studied medicine for a time, but, devoting himself to chemistry, became in 1845 a private student with Prof. B. Silliman, jr., of New Haven, acting meanwhile as chemical assistant to Prof. Silliman, sr., in the laboratory of Yale college. After two years thus spent he was in 1847 made chemist and mineralogist to the geological survey of Canada, then just begun under the direction of Sir William Logan. He held this post for more than 25 years, but resigned it in 1872, and accepted the chair of geology in the Massachusetts institute of technology, where he succeeded Prof. William B. Rogers. His earlier studies were directed especially to theoretical chemistry, then assuming shape from the labors of Liebig, Dumas, Laurent, and Gerhardt. It was as the reviewer, interpreter, and critic of these chemists that Mr. Hunt first became known, while he at the same time developed from some germs in the writings of Laurent a new system essentially his own, in which all chemical compounds are deduced from simple types represented by one or more molecules of water or of hydrogen.

These views, maintained by him in a series of papers in the " American Journal of Science," beginning in 1848, have at length been universally adopted, and are now recognized as one of the foundations of modern chemical theory. His philosophy of the sciences has been influenced by the study of Kant, and still more of Hegel and Stallo, as may be seen in his essays on " Solution," " Chemical Changes," and "Atomic Volumes," which first appeared in the "Journal " (1853-'4), and were republished in England and Germany. In these he attacks the atomic hypothesis and all its consequences, and asserts that solution is chemical union, and chemical union identification. His researches on the equivalent volumes of liquids and solids were a remarkable anticipation of those of Dumas, while in his inquiries into the polymerism of mineral species he has opened a new field for mineralogy, as set forth later in his essay on the " Objects and Method of Mineralogy." His philosophical studies have however been only incidental to his labors in chemical mineralogy and chemical geology.

His researches into the chemical and mineral composition of rocks have probably been more extended than those of any other living chemist; and his investigations of the chemistry of mineral waters, which are not. less so, have enabled him to frame a complete theory of their origin and formation, and their relations to the origin of rock masses both crystalline and uncrystalline, and to lay the basis of a rational system of chemical geology. From his long series of studies of the salts of lime and magnesia he was enabled to explain for the first time the true relations of gypsums and dolomites, and to explain their origin by direct deposition. His views on this subject are now, after many years, finding recognition among geologists. He has also carefully investigated petroleum both in its chemical and geological relations. The phenomena of volcanoes and igneous rocks have been discussed by him from a new point of view, and he has revived and enforced the almost forgotten hypothesis of Keferstein that the source of these is to be sought in chemical reactions set up in the sedimentary deposits of the earth's crust through the agency of internal heat.

In this discussion he was the first to point out and explain the relation between modern volcanic phenomena and great accumulations of comparatively recent sedimentary formations, as well as the nature of the relations between these and folded and contorted strata. He has sought to harmonize the facts of dynamical geology with the notion of a solid globe, which he early adopted in opposition to the generally received one of a globe with a liquid interior, and has also developed a theory of cosmogony based upon the chemical and physical conditions of a world consolidating from a vaporous mass, and has endeavored to show how the earth, air, and ocean have assumed their present condition under the slow operation of natural causes. His views on these questions will be found in an essay on "The Chemistry of the Earth" in the report of the Smithsonian institution for 1869; while his conclusions on many points of geology are embodied in his address delivered as retiring president before the American association for the advancement of science at Indianapolis in 1871, on "The Geognosy of the Appalachians and the Origin of Crystalline Rocks," and in others of his recent papers, such as "Notes on Granitic Rocks," "The Geognos-tical Relations of the Metals," and " The History of the Names Cambrian and Silurian in Geology." Besides his papers in the " American Journal of Science," which number more than 100, and numerous articles communicated to the French academy and the scientific journals of France, England, and Canada, he has contributed largely to the reports of the geological survey of Canada, and to the work entitled "Geology of Canada" (1863), the latter half of which is from his pen.

He is also the author of a summary of organic chemistry forming a part of Prof. Silliman's " First Principles of Chemistry " (1852). A volume of his collected scientific essays is now in press (1874). He is also known for his researches, both theoretical and practical, into the chemistry and metallurgy of iron and of copper, some of which will be found in the "Proceedings of the American Institute of Mining Engineers." Dr. Sterry Hunt received in 1854 the honorary degree of A. M. from Harvard college, and later the degrees of LL. D. and Sc. D. from the universities of Montreal and Quebec, in both of which he was for many years a professor, and in the latter of which ho lectured in the French language. He was a member of the international jury at the exhibitions of Paris in 1855 and 1867, and is a member of various academies and learned societies both in Europe and America. He was made a fellow of the royal society of London in 1859, and of the national academy of the United States in 1873. He is also an officer of the French order of the legion of honor.