JACKSON, Charles Thomas, scientist, born in Plymouth, Massachusetts, 21 June, 1805; died in Somerville, Massachusetts, 28 August, 1880. He was graduated at the Harvard medical college in 1829, but previously, with Francis Alger, had made a geological and mineralogical survey of Nova Scotia, of which he published a preliminary account in 1827 and a fuller description in 1829. Dr. Jackson then went to Europe and pursued medical and scientific studies in Paris, where he met many distinguished men, including Elie de Beaumont, the geologist, with whom he maintained a life-long friendship. In 1831 he made a pedestrian tour through central Europe, and, visiting Vienna during the prevalence of the cholera, he assisted in the dissection of the bodies of two hundred victims of that disease. In 1832 he published a detailed account of his observations in the "Boston Medical Journal." While in Paris his attention was directed to recent discoveries in electricity and magnetism, and accordingly experimented with a view to the utilization of electricity for telegraphy. On his homeward voyage, in 1832, he communicated his ideas to Samuel F. B. Morse, who, as it was afterward shown, had no previous acquaintance with the subject of electricity, in 1834 he constructed, successfully worked, and exhibited to his friends, a telegraphic apparatus, similar to the model that was patented a year later by Mr. Morse, priority over which was always claimed by Dr. Jackson. Meanwhile he settled in Boston, where he practised medicine, but soon abandoned that profession, and in 1838 opened a laboratory for instruction and research in analytical chemistry, which was the first of its kind in the United States. In 1836 he was appointed state geologist of Maine and surveyor of public lands, and he spent three years in the execution of this work, publishing three annual " Reports on the Geology of the State of Maine" (Augusta, 1837-'9), and two "Reports on the Geology of the Pub-lie Lands belonging to the Two States of Massachusetts and Maine" (Boston, 1837 and 1838). He was appointed state geologist of Rhode Island in 1839, and published in that connection "Report on the Geological and Agricultural Survey of Rhode Island" (Providence, 1840). Subsequently he was engaged on a geological survey of New Hampshire, and during the three years spent in this work issued "Reports of the Geology of New Hampshire" (Concord, 1841-'4). About this time he drew up a plan for the geological survey of New York, which was adopted. Dr. Jackson explored the southern shores of Lake Superior in 1844, and was the first to call attention to the mineral resources of that country. In the following year he returned to the same region, opened copper mines, and also discovered iron mines. In 1847 he was appointed by congress to survey the mineral lands of Michigan, but two years later was displaced in consequence of political changes in the National government, and published a "Report on the Mineral Lands of the United States in Michigan" (1849). His name has been prominently mentioned in connection with the discovery of the anaesthetic properties of ether and nitrous oxide, to which claim has been laid by Dr. William T. G. Morton and Dr. Horace Wells, two physicians who had studied with him. Dr. Jackson's claims for priority were substantially as follows: He had already experimented on the anaesthetic properties of chloroform and of nitrous-oxide gas, and previous to the winter of 1841-'2, having received some perfectly pure sulphuric ether, he tried its effects upon himself, administering it with a mixture of atmospheric air, and inhaled it to such an extent as to lose all consciousness, without suffering any of the dangerous or disagreeable consequences that had hitherto attended the inhalation of impure sulphuric ether unmingled with atmospheric air. In the winter of 1841-'2 he inhaled ether vapor for relief from the very severe pain occasioned by the accidental inhalation of chlorine. The relief he experienced led him to infer "that a surgical operation could be performed on a patient under the full influence of sulphuric ether without giving him any pain." The first practical use of anaesthesia produced by ether was in 1846, when it was administered to a patient from whose jaw a tumor was removed by Dr. John C. Warren at the Massachusetts general hospital. In 1852 a memorial was presented to congress, signed by 143 physicians of Boston and its vicinity, ascribing the discovery exclusively to Dr. Jackson. About the same time the question was investigated by a committee of the French academy of sciences, and on their report the academy decreed a prize of 2,500 francs to Dr. Jackson, and another of 2,500 francs to Dr. Morton. M. Elie de Beaumont remarked in a letter to Dr. Jackson, dated 17 May, 1852; "In point of fact, the Academy of sciences decreed one of the Montyon prizes of 2,500 francs to you for the discovery of etherization, and it has decreed a prize of 2,500 francs to Mr. Morton for the application of this discovery to surgical operations." He published a "Manual of Etherization, with a History of its Discovery" (Boston, 1861). Dr. Jackson received, besides various orders and decorations from the governments of France, Sweden, Turkey, and Sardinia, that of the red eagle, from the king of Prussia, on the recommendation of Humboldt. His scientific discoveries were very numerous, and included a powerful blast-lamp for alkaline fusions, which was very serviceable prior to the introduction of illuminating gas into laboratories. He first demonstrated by his analysis of the meteoric iron of Alabama the presence of chlorine in that class of bodies and discovered the deposits of emery in Chester, Massachusetts Dr. Jackson was one of the early members and long vice president of the Boston society of natural history. His separate papers comprise very nearly 100 titles, and were contributed to scientific journals both in the United States and Europe. In 1873 his mind became deranged by the constant anxiety and worry incidental to the controversies in which he was engaged, and the remainder of his life was passed in retirement.