Page:Dictionary of National Biography, Second Supplement, volume 1.djvu/118

 BARLOW, WILLIAM HENRY (1812–1902), civil engineer, born at Woolwich on 10 May 1812, was younger son of Peter Barlow [q. v.] and brother of Peter William Barlow [q. v. Suppl. I]. After education at home by his father he received three years' practical training, at first in the machinery department of Woolwich dockyard, and then at the London Docks under Henry Robinson Palmer, the engineer-in-chief. At twenty he was sent by Messrs. Maudslay and Field to Constantinople, where he spent six years on the erection of machinery and buildings for the manufacture of ordnance for the Turkish government. For the Porte he also reported on the lighthouses at the mouth of the Bosporus in the Black Sea, and the work suggested a paper, which he communicated to the Royal Society, on the adaptation of different modes of illuminating lighthouses (Phil. Trans. 1837, p. 211). For his services in Turkey he was decorated with the order of the Nischan-el-Iftikar. On returning to England in 1838 he became assistant engineer on the construction of the Manchester and Birmingham railway, in 1842 resident engineer on the Midland Counties railway, and in 1844 resident engineer to the North Midland and the other lines which were amalgamated during that year to form the Midland railway. Of the Midland railway he became principal engineer-in-charge, and in 1857 he removed as the company's consulting engineer from Derby to London. The saddleback form of rail which bears his name was invented by him during this period (of. his patent No. 12438 of 1849); and between 1844 and 1886 he took out, either alone or in conjunction with others, several other patents relating to permanent way. In 1862-9 Barlow, who carried out many improvements of the Midland railway, laid out and constructed the southern portion of the London and Bedford line, including St. Pancras Station with its fine roof (opened 1 Oct. 1868; cf. Proc. Inst. Civ. Eng. xxx a 78). Meanwhile in 1860 he designed, with Sir John Hawkshaw [q. v. Suppl. I], the completion of the Clifton suspension bridge (cf. ib. xxvi. 243).

Concurrently with his constructional work Barlow carried on many scientific researches. In 1847 he observed certain spontaneous diurnal deflections of the needles of railway telegraph-instruments, as well as spasmodic movements corresponding with magnetic storms. These he attributed to electric currents on the earth's surface (cf. his paper in Phil. Trans. 1849, p. 61). Another communication to the Royal Society in 1874 (Proc. xxii. 277) describes the 'logograph,' an instrument which he devised for recording graphically the sound waves caused by the human voice, and which was a forerunner of the telephone and phonograph. But his chief scientific inquiries concerned the theory of structures. In 1846 he presented to the Institution of Civil Engineers (Proc. v. 162) a paper 'On the Existence (practically) of the Line of Equal Horizontal Thrust in Arches, and the Mode of determining it by Geometrical Construction.' Later he investigated practically the strength of beams (cf. three papers in Phil. Trans. 1855, p. 225; ib. 1857, p. 463; and Proc. E.S. xviii. 345). In 1859 he made experiments on continuous beams, which indicated the advantages of increasing the depth of such beams over the points of support (cf. his patent No. 908 of 1859).

Barlow was often consulted on engineering principles, as well as on large structural designs. He was a member of a committee of engineers formed in 1868 to investigate the applicability of steel to structures, and after he had urged the advantages of steel in his address to the mechanical science section of the British Association in 1873, the board of trade appointed a committee of inquiry (on which he served) which recommended (1877) the 6½ tons limit of working-stress for steel. Barlow was a member of the court of inquiry into the Tay bridge disaster (1879) which counselled a precise calculation of the stresses due to wind-pressure, and he served on the board of trade committee which defined an allowance of 56 lbs. per square foot for such pressure.

Consulted by the directors of the North British railway in regard to reconstruction of the Tay bridge, he recommended an independent viaduct, which was commenced in 1882 and opened for traffic 20 June 1887 (for a description by Barlow's son, Crawford, see Proc. Inst. Civil Eng. 1888, xciv. 87).

Barlow was one of three consulting engineers to whom the railway companies concerned referred the question of bridging the Forth after the collapse of the Tay bridge [cf. art. , Suppl. I], and he submitted two designs (suspension bridges with braced chains); but the type of bridge proposed by (Sir) Benjamin Baker [q. v. Suppl. II] was adopted, with certain modifications in the piers to meet objections taken by Barlow.

Barlow attained a chief place in his 