494 JACKSON lege in 1796, and in December, 1797, became a pupil of Dr. Edward Augustus Holyoke of Sa- lem, with whom he studied nearly two years. He then went to London, where he was a " dresser " in St. Thomas's hospital, and at- tended lectures at that and at Guy's hospital. After his return he practised in Boston. In 1810, in connection with Dr. John 0. Warren, he brought before the community a proposition for establishing a hospital in Boston. The re- sult was the organization of the asylum for the insane at Somerville, and afterward of the Massachusetts general hospital in Boston, of which Dr. Jackson was the first physician. In 1810 he was chosen professor of clinical medicine in Harvard college, and two years af- terward professor of theory and practice. In 1835 he resigned his place as physician to the hospital and his office in the medical school. He was several times chosen president of the Massachusetts medical society. His principal publications are : " On the Brunonian System " (1809); "Remarks on the Medical Effects of Dentition," in the "New England Medical and Surgical Journal" (1812); various articles in the "Transactions of the Massachusetts Med- ical Society," including some reports drawn up principally or entirely by him, viz. : " On Cow Pox and Small Pox," "On Spotted Fever," and "On Spasmodic Cholera;" "Eulogy on Dr. John Warren" (1815); "Syllabus of Lec- tures" (1816), and "Text Book of Lectures" (1825-'7), for the use of the medical class; a memoir of his son James Jackson, jr. (1835) ; "Letters to a Young Physician" (1855); and " Another Letter to a Young Physician " (1861). III. Patrick Tracy, an American merchant, broth- er of the preceding, born in Newburyport, Aug 14, 1780, died in Beverly, Sept. 12, 1847. At the age of 15 he was apprenticed to William Bartlett, a merchant of Newburyport, and subsequently established himself in Boston in the India trade, in which he acquired a handsome fortune. In 1812, at the invitation of his brother-in-law, Francis C. Lowell of Boston, who had recently examined the process of the cotton manufac- ture in England, he engaged in a project to in- troduce the power loom, then newly invented, and the mode of constructing which was kept secret, into the United States. As the war be- tween the United States and England prevent- ed communication with the latter country, they were forced to invent a power loom them- selves, and, after repeated failures, succeeded in the latter part of 1812 in producing a model from which a machine was constructed by Paul Moody. In 1813 they built their first mill at Waltham, near Boston, which is said to have been the first in the world that combined all the operations for converting the raw cotton into finished cloth. In 1821 Mr. Jackson made large purchases of land on the Merrimack river near the Pawtucket canal, on which a number of mills were constructed by the Mer- rimack manufacturing company, organized un- der his auspices. This settlement formed the germ of the city of Lowell. After superin- tending the formation of another company in the same place, he procured in 1830 a charter for a railroad between Lowell and Boston, the construction of which he directed until its completion in 1835. It was then probably the finest work of the kind in the country. Pecu- niary reverses having overtaken him in 1837, he assumed the charge of the locks and canals company of Lowell, and subsequently of the Great Falls manufacturing company at Somers- worth, N. II., managing both with complete success. He labored zealously to promote the moral and intellectual improvement of the operatives in his mills. See memoir of P. T. Jackson, by John A. Lowell, in Hunt's " Lives of American Merchants " (New York, 1856-'8). JACKSON, Charles Thomas, an American phys- icist, born in Plymouth, Mass., June 21, 1805. He devoted much attention to science in his youth, studied medicine under Drs. James Jackson and Walter Channing, and received the degree of M. D. from Harvard university in 1829. In 1827 and 1829 he made, in com- pany with Francis Alger of Boston, a miner- alogical and geological survey of Nova Scotia, an account of which was published by them, together with a geological map of the province, in the " Memoirs of the American Academy of Arts and Sciences." In the autumn of 1829 he went to Europe, where he remained three years, studying in Paris. In 1831 he made a pedestrian tour through Switzerland, Pied- mont, Lombardy, Tyrol, Bavaria, and Austria. He afterward visited the principal cities of Italy, and made a geological tour of Sicily and of Auvergne in France. In October, 1832, he embarked for New York in the packet ship Sully, taking with him an electro-magnet, two galvanic batteries, and other philosophical ap- paratus. During the voyage a discussion arose among the passengers, of whom Prof. S. F. B. Morse was one, on the subject of electro-mag- netic experiments, and their applicability to telegraphic use. Dr. Jackson asserts that du- ring this discussion he pointed out the possibil- ity of correspondence by means of electricity, and suggested several ways of accomplishing it. His plan as then developed in conversation, he declares, embraced the essential and peculiar features of the American telegraph patented in 1840 by Prof. Morse. Dr. Jackson also asserts that in the spring of 1834 he constructed and successf ally worked, and exhibited to Francis Alger and other friends, a telegraph combining the peculiar features of that which he had in- vented on board the Sully, though he did not think it could be profitably brought into public use till the invention of the sustaining battery by Daniell in 1837 furnished the means of ob- taining a long continued voltaic current of uni- form strength. A controversy arose in 1837 between Morse and Jackson upon their respec- tive claims, the evidence in regard to which was printed for the use of the court and coun- sel in subsequent trials of telegraph causes. In
