ROEBLING, John Angustus (ray'-bling), civil engineer, born in Muhlhausen, Prussia, 12 June, 1806; died in Brooklyn, New York, 22 July, 1869. He was graduated at the Royal polytechnic school in Berlin with the degree of C. E. in 1826, paid special attention to suspension-bridges during his course, and wrote his graduating thesis on this subject. After spending the three years required by law in government service, during which time he was engaged chiefly as an assistant on the construction of military roads in Westphalia, he came to the United States. He settled near Pittsburg, Pennsylvania, where he devoted himself to agricultural pursuits, and determined to build a village of frontiersmen. The various systems of canal improvements and slack-water navigation were then in course of development, and to these his services were attracted. Later his attention was given to new railroad enterprises. One of his earliest engagements was in surveying the lines of the Pennsylvania railroad across the Alleghany mountains from Harrisburg to Pittsburg. He then entered upon the manufacture of iron and steel wire, from which he gained the valuable knowledge of the nature, capabilities, and requirements of wire that enabled him to revolutionize the construction of bridges. The first specimens of that wire that was ever produced in the United States were made by him, and his belief in its efficacy for bridge-construction was soon put to the test. During the winter of 1844-'5 he had charge of the building of a wooden aqueduct across the Alleghany river at Pittsburg, and proposed that it should consist of a wooden trunk to hold the water, supported on each side by a continuous wire cable seven incites in diameter. In spite of ridicule from the engineering profession, he succeeded in completing his bridge, which comprised seven spans, each of 162 feet. His next undertaking was the construction in 1846 of a suspension-bridge over Monongahela river at Pitts-burg. In 1848 he built four similar works on the line of the Delaware and Hudson canal. On the completion of these bridges he settled in Trenton, New Jersey, whither he removed his wire-manufactory. In 1851 he was called to build a suspension-bridge across the Niagara river to connect the , New York Central railroad with the Canadian railway systems. This structure, the first of the great suspension-bridges with which his name is connected, was built in four years, and, when it was finished, was regarded as one of the wonders of the world. I} was the first suspension-bridge that was capable of bearing the weight of railroad-trains. The span was 825 feet clear, and it was supported by four 10-inch cables. His next undertaking was a wire-cable bridge for common travel over Alleghany river at Pittsburg, which is considered one of the best pieces of bridge engineering in existence. In 1856 he began the building of the great bridge between Cincinnati and Covington, but the work was not finished until 1867. Its success showed engineers throughout the country that the problem of suspension-bridge making was solved upon a principle that could not be superseded. According to General John G. Barnard, "to Mr. Roebling must be conceded the claim of practically establishing the sufficiency of the suspension principle for railroad bridges and of developing the manner of their construction." His eminent success in this line of work led in 1868 to his being chosen chief engineer of the East river bridge, connecting Brooklyn and New York. He at once prepared plans for the structure, which received the approval of the National authorities, and in 1869 the company for the construction of the bridge was duly organized and work was at once begun. While he was making observations his foot was crushed between the piling and rack of one of the ferry-slips during the abrupt entry of a ferry-boat. Mr. Roebling was then removed to his residence, but, in spite of medical skill, his death occurred from lockjaw sixteen days later. Mr. Roebling published "Long and Short Span Railway Bridges" (New York, 1869). --His son, Washington Augustus, civil engineer, born in Saxenburg, Pennsylvania, 26 May, 1887, was graduated as a civil engineer at Rensselaer polytechnic institute in 1857, and began his professional work at once under his father on the Alleghany suspension-bridge. In 1861 he enlisted as a private in the 6th New York artillery, and served a year with that battery in the Army of the Potomac. In 1862 tie was transferred to the staff of General Irvin Mc-Dowell, and assigned to various engineering duties, notably the construction of a suspension-bridge across Rappahannock river. Later he served on General John Pope's staff, and was present at South Mountain, Antietam, and the campaign that ended in the second battle of Bull Run, during which time he built a suspension-bridge across Shenandoah river at Harper's Ferry. He was also engaged on balloon duty, and was in the habit of ascending every morning in order to reconnoitre the Confederate army. By this means he discovered, and was the first to announce, the fact that, General Lee was moving toward Pennsylvania. From August, 1863, till March, 1864, he was attached to the 2d corps, serving on engineering duty and then on staff duty with the 5th corps during the overland campaign. He attained the rank of major on 20 April, 1864, also receiving three brevets, including that of colonel, and resigned in January, 1865. Colonel Roebling then assisting his father on the Cincinnati and Covington bridge, of which he had almost the entire charge. He then went abroad to study pneumatic foundations before sinking those of the East river bridge, to the charge of which he was called on the death of his father, but before any of the details had been decided on. In 1869 he settled in Brooklyn, and gave his attention almost exclusively to the sinking of the caissons. His devotion to the work, with the fact that he spent more hours of the twenty-four in the compressed air of the caissons than any one else, led to an attack of caisson fever early in 1872. He soon rallied and resumed his work, but he was so weak that he was unable to leave his room. Nevertheless, he prepared the most minute and ex-: act directions for making the cables, and for the erection of all the complicated parts of the superstructure. In 1873 he was compelled to give up work entirely, and spent several months in Europe, but on his return he resumed charge of the bridge, which he held until its completion in 1883. The structure he built, which is the longest suspension-bridge in the world, cost about $13,000,000. The picture shows it before completion. Its total length, in-eluding approaches, is 5,989 feet, of which the middle span takes up 1,596 feet, while the length of the suspended structure from anchorage to anchorage is 3,456 feet. He has since spent his time in directing the wire business in Trenton, New Jersey, and in the recuperation of his health. Besides various pamphlets on professional subjects, he is the author of "Military Suspension-Bridges" (Washington, 1862).