HUNT, Thomas Sterry, scientist, born in Norwich, Connecticut, 5 September, 1826. He received his early education in his native town, and there began the study of medicine, but soon abandoned it for that of chemistry, which he followed in New Haven under the younger Silliman. Meanwhile he also acted as assistant in chemistry to the elder Silliman in the Yale laboratory, and, after spending two years in New Haven, he was offered the appointment of chemical assistant in the newly established school of agricultural chemistry in Edinburgh, Scotland, which he declined in order to accept that of chemist and mineralogist to the geological survey of Canada, under Sir William E. Logan. He continued in this office until 1872, and also held the chair of chemistry in Laval university, delivering his lectures in French, from 1856 till 1862, and a similar professorship from 1862 till 1868 at McGill university. In 1872 he became professor of geology in the Massachusetts institute of technology, succeeding William B. Rogers, holding that chair until 1878, and since that time has held no official appointment. Early in his career he became known by a series of papers on theoretical chemistry, which appeared in Silliman's "American Journal of Science" from 1848 till 1851. Hunt developed a system of organic chemistry that was essentially his own, in which all chemical compounds were shown to be formed on simple types represented by one or more molecules of water or hydrogen. An account of the development of this subject will be found in his paper read at the centennial of chemistry that was held in Northumberland, Pennsylvania, August, 1874, entitled "A Century's Progress in Chemical Theory." 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 in his paper on the "Objects and Method of Mineralogy" but these philosophical studies have been only incidental to his labors in chemical mineralogy and chemical geology. Hunt's researches into the chemical and mineral composition of rocks have probably been more extended than those of any other contemporary scientist. The names Laurentian and Huronian, applied to the earliest known rocks on this continent, were given by him to the two subdivisions of the Eozoic period. From his long series of investigations of the lime and magnesia salts 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 have found a wide recognition among geologists. 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 that the source of these is to be found in chemical reactions. He has also sought to harmonize the facts of dynamical geology with the theory of a solid globe. 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 era-bodied in his address delivered as retiring president before the American association for the advancement of science at Indianapolis in 1871. He was the first to make known the deposits of phosphates of lime in Canada, and to call attention to its commercial value as a fertilizer. The chemical and geological relations of petroleum have been carefully investigated by him, and he has studied in detail the salt deposits of Ontario. During the later years of his connection with the geological survey of Canada, its administrative details were under his charge. During 1875-'6 he was connected with the geological survey of Pennsylvania. In 1859 he invented a permanent green ink, which has been very extensively used, and gave the name of "greenback" currency to the bills which were printed with it. He is a popular speaker on scientific subjects, and has delivered two courses of lectures before the Lowell institute in Boston. He served on juries at the world's fair in Paris in 1855 and in 1867, being made an officer of the legion of honor on the latter occasion, and was also one of the judges at the world's fair in Philadelphia in 1876. The degree of LL.D. was given to him by McGill in 1857, that of Sc.D. by Laval in 1858, and that of LB. D. by Cambridge, England, in 1881. He is a member of many societies, and, besides having held the presidency of the American association for the advancement of science in 1871, has filled a like office in the American institute of mining engineers in 1877, in the American chemical society in 1880, and in the Royal society of Canada in 1884. In 1876 he organized, in concert with American and European geologists, the International geological congress, and was made secretary at its first meeting, hehl in Paris in 1878, and vice president at the meeting hehl in Bologna, Italy, in 1881. He was elected a member of the National academy of sciences in 1873, and in 1859 a fellow of the Royal society of London. His bibliography includes upward of 200 titles of separate papers that have appeared in reports of the geological survey of Canada, the transactions of learned societies, and scientific periodicals. He has published in book-form "Chemical and Geological Essays" (Boston, 1874); "Azoic Rocks" (Philadelphia, 1878); "Mineral Physiology and Physiography" (Boston, 1886); "A New Basis for Chemistry" (1887); and has in preparation (1887) "Mineralogy according to a Natural System."