ELLICOTT, Andrew, American astrono mer and civil engineer: b. Bucks County, Pa., 24 Jan. 1754; d. West Point, N. Y., 28 Aug. 1820. His father founded the town of Ellicott's Mills, Md., where the younger days of • his son Andrew were devoted to the study of the sciences and practical mechanics. The latter's scientific attainments early attracted public at tention, and from the Revolution to the day of his death he was employed in the fulfilment of trusts conferred by the general or State gov ernments. About 1785 he removed to Balti more, and represented the city in the State legislature. In 1789 he was appointed by Presi dent Washington to survey the land lying be tween Pennsylvania and Lake Erie, and that year made the first accurate measurement of the Niagara River from lake to lake, with the height of the falls and the fall of the rapids. In 1790 he was employed by the government to survey and-lay out the 'Federal Metropolis. In 1792 he was made Surveyor-General of the United States, and in 1795 superintended the construction of Fort Erie at Presque Isle (now Erie, Pa.), and was employed in laying out the
towns of Erie, Warren and Franklin. In 1796 he was appointed by President Washington commissioner on behalf of the United States under the Treaty of San Lorenzo el Real, to de termine the southern boundary separating the United States territory from the Spanish pos sessions. The results of this service, embracing a period of nearly five years, appear in his 'journal) (published 1803). upon the comple tion of this service he was appointed by Gov ernor McKean of Pennsylvania secretary of the State land office, the duties of which he performed to the year 1808, and in 1812 became professor of mathemathics at West Point. In 1817, by order of the government, he proceeded to Montreal to make astronomical observations for carrying into effect some of the articles of the Treaty of Ghent.