# Dictionary of National Biography, 1912 supplement/Donkin, Bryan

​DONKIN, BRYAN (1835–1902), civil engineer, born at 88 Blackfriars Road, London, on 29 Aug. 1835, was eldest son in a family of four sons and three daughters of John Donkin (1802–1854), civil engineer, and grandson of Bryan Donkin, F.R.S. [q. v.]. His mother was Caroline, daughter of Benjamin Hawes. He was educated at private schools and at University College, London, and then pursued for two years an engineering course at the École centrale des Arts et Metiers in Paris. From 1856 to 1859 he served three years' apprenticeship in the Bermondsey engineering works of Bryan Donkin & Company, which his grandfather established in 1803. He was then engaged in St. Petersburg on some very large mills, which his firm were erecting for the Russian government for the production of paper for making banknotes and other purposes. He returned to the Bermondsey works in 1862, and became a partner in 1868. The firm was formed into a limited liability company in 1889 with Donkin as chairman. In 1900 there was an amalgamation with Messrs. Clench & Company of Chesterfield. He remained chairman for a time, though he ceased to take an active part in the management.
Donkin devoted much time and labour to scientific research, and proved to be an able, indefatigable, and accurate investigator. His researches were especially directed to the design and construction of heat-engines and steam-boilers and to the application to them of scientific tests. One of the first to practise systematic testing of the efficiency of steam-engines, he introduced a method of determining steam-consumption by measuring the condensed water flowing over a tumbling bay or weir. His researches into the action and behaviour of steam in the cylinders of steam-engines, and the advantages of jacketing, formed the subject of four papers presented to the Institution of Civil Engineers (Minutes of Proceedings, xcviii. 250; c. 347; cvi. 264, and cxv. 263), and two to the Institution of Mechanical Engineers (Proc. 1893, p. 480; 1895, p. 90). In the course of these experiments he perfected his 'revealer,' an apparatus of glass which, attached to the cylinder of a steam-engine, rendered visible the condensation effects taking place within the cylinder. Meanwhile, after close study of internal-combustion engines, he published 'A TextBook on Gas, Oil and Air Engines,' 1894 (5th edit. 1911), and in 1894 he also translated Rudolf Diesel's 'Theory and Construction of a Rational Heat Motor.'
His latest inquiry was into the practicability of working gas-engines with the gases produced in blast-furnaces, and a few weeks before his death he contributed to the 'Proceedings of the Institution of Civil Engineers' an important paper on 'Motive Power from Blast-Furnace Gases' (cxlviii. 1). He was a member of committees appointed by the Institution to report upon standards of thermal efficiency for steam-engines and on the tabulation of results of steam-engine and boiler trials. He was also a member of research committees of the Institution of Mechanical Engineers on the steam-jacket, on marine engines, on gas-engines, and on steam-engines. In conjunction with (Sir) Alexander Kennedy he made exhaustive tests of different types of boilers, the results of which were published in 'Engineering' from 1890 onwards, and he was author of 'The Heat Efficiency of Steam Boilers' (1898). Fuel calorimeters (Proc. Inst. Civ. Eng. cii. 292), centrifugal fans (ibid. cxxii. 265), the velocity of air through pipes (ibid. cxi. 345), the Perret system of forced draught (Proc. North of Eng. Inst. Min. and Mech. Eng. xlii. 32), and heat-transmission (Proc. Inst. Mech. Eng. 1896, p. 501) were among the other subjects of investigation.
He was elected a member of the Institution of Civil Engineers on 5 Feb. 1884, and received its Watt medal in 1894, Telford premiums in 1889 and 1891, and a Manby premium in 1896, in recognition of the value of papers contributed to the Institution's 'Proceedings.' He was also, from 1873, a member of the Institution of Mechanical Engineers, and became a member of council in 1895 and a vice-president in 1901. He died suddenly at the Grand Hotel, Brussels, on 4 March 1902, and was buried at ​Bromley, Kent. He married twice: (1) in 1869, Georgina, daughter of Frank Dillon, by whom he had issue one daughter and one son; (2) Edith Marshman Dunn (born Edith Marshman), by whom he had a daughter.
[Minutes of Proc. Inst. Civ. Eng. cl. 428; Proc. Inst. Mech. Eng. 1902, p. 378; Engineering, lxxiii. 320.]
W. F. S.