ROBERTS, William Milnor, civil engineer, born in Philadelphia, 12 February, 1810; died in Brazil, South America, 14 July, 1881. His father was Thomas P. Roberts, treasurer of the Union canal, the first work of that kind undertaken in Pennsylvania. In 1825 the son was employed as chainman on canal surveys under Canvass White. At the age of eighteen he was given charge of the most difficult division of the Lehigh canal, and two years later he was appointed resident engineer in charge of the Union railroad and Union canal feeder. In 1831-'4 he was senior principal assistant engineer on the Allegheny Portage railroad. In 1835 he planned and built the first combined railroad and highway bridge in this country. It crossed the Susquehanna at Harrisburg, and was nearly a mile long. The piers are still used to support the great iron bridge of the Cumberland Valley railroad. In 1835 he was made chief engineer on the Harrisburg and Lancaster railroad, and during the same year he was also appointed chief engineer of the Cumberland Valley railroad, which work was completed by him. After 1836 he was chief engineer in charge of the Monongahela river slackwater navigation, the Pennsylvania state canal, and the Erie canal of Pennsylvania. In 1841-'2 he was a contractor on the Welland canal enlargement, in 1845-'7 chief engineer and agent for the trustees of the Sandy and Beaver canal company, Ohio, in 1847 chief engineer of the Pittsburg and Connellsrifle railroad. In 1849 he declined the appointment of chief engineer of the first proposed railroad in South America (in Chili), to take that of the Bellefontaine and Indiana railroad, which he held until 1851. In 1852-'4 he was chief engineer of the Allegheny Valley railroad, consulting engineer of the Atlantic and Mississippi railroad, a contractor for the whole Iron Mountain railroad of Missouri, and chairman of a commission of three appointed by the Pennsylvania legislature to examine and report upon routes for avoiding the old Allegheny portage inclined planes. In 1855-'7 he was contractor for the entire Keokuk, Des Moines, and Minnesota railroad, consulting engineer for the Pittsburg and Erie, and Terre Haute, Vandalia, and St. Louis railroads, and chief engineer of the Keokuk, Mt. Pleasant, and Muscatine railroad. In 1857 he went to Brazil to examine the route of the Dom Pedro II. railroad, and, in company with Jacob Humbird, of Maryland, and other Americans, undertook the construction of that work. He returned to the United States in 1865, and at once took the field in the interests of the Atlantic and Great Western railroad for a proposed extension through northern Pennsylvania. In 1866 he was appointed United States civil engineer and given charge of the improvement of the Ohio river, which work he relinquished in 1868 to accept the appointment of associate chief engineer with James B. Ends on the great bridge across the Missouri at St. Louis. During Mr. Eads's absence in Europe of a year and more, Mr. Roberts had entire charge of the work at its most arduous and difficult stage. In 1870 he accepted the chief engineership of the Northern Pacific railroad, and in 1874 was appointed on the commission of civil and military engineers to examine and report upon plans for the improvement of the mouth of the Mississippi, visiting the various rivers in Europe where jetties had been constructed. In 1879 he was appointed by the emperor of Brazil chief of the commission of hydraulic engineers to examine and report upon the improvement of harbors and navigable rivers of that empire, tie had nearly completed the period of his service when he died of fever on the head-waters of San Francisco river. Mr. Roberts was a contributor, generally anonymously, to newspapers and scientific magazines. In 1879 he was elected president of the American society of civil engineers, and at the same time he became a member of the English institute of engineers and a fellow of the American geographical society. In 1836 he married a daughter of Chief-Justice John Bamlister Gibson, of Pennsylvania (q. v.). --His son, Thomas Paschall, civil engineer, born in Carlisle, Pennsylvania, 21 April, 1843, was educated at Pennsylvania agricultural college and at Dickinson college, and in 1863 joined his father in Brazil, where he was employed as an engineer on the Dom Pedro II. railway. He returned to the United States late in 1865. In the autumn of 1866 he was appointed principal assistant engineer on the United States improvement of the Ohio river, which post he retained until October, 1870, when he became assistant engineer of the Montana division of the Northern Pacific railway. He made the first examination of the route that was finally adopted through the Rocky mountains for that road, and also examined and reported upon the navigability of the upper Missouri river. His report, with maps, was printed by the war department in 1874. He was appointed in 1875 by the United States government to the charge of the surveys of the upper Monongahela river in West Virginia, and in 1876-'8 was chief engineer of the Pittsburg southern railroad. Subsequently he was engaged as chief engineer in charge of the construction of several southern roads until 1884, when he was appointed chief engineer of the Monongahela navigation company, and he has since been engaged in the extension of new locks for double locking this important system of steamboat navigation.