Sir Dugald Clerk (18541932), by Archibald Standish Hartrick, 1906
Clerk, Sir Dugald (18541932), mechanical engineer, was born at Glasgow on 31 March 1854, the eldest son of Donald Clerk, machinist, of Glasgow, and his wife, Martha Symington, second daughter of John Brown, of Glasgow. He was about fifteen years old when he began his training in the drawing office of H. O. Robinson & Co., of Glasgow, and in his father's works, also attending classes at Anderson's University, Glasgow. From 1871 to 1876 he studied at Anderson's University and the Yorkshire College of Science, Leeds, under the chemist T. E. Thorpe, who made him one of his assistants and set him to work on the fractionation of petroleum oils. He had intended to become a chemical engineer, but after seeing a Lenoir gas engine at work in a joiner's shop in Glasgow, this and other forms of the internal combustion engine became the leading interest of his life.
After his return to Glasgow, Clerk was for a short time assistant to E. J. Mills, the Young professor of technical chemistry at Anderson's University; he then devoted himself to research on the theory and design of the gas engine, first with the Glasgow firm of Thomson, Sterne & Co., from 1877 to 1885, then with Messrs Tangyes, of Birmingham. Clerk married, in 1883, Margaret (d. 1930), elder daughter of Alexander Hanney, of Helensburgh.
In 1888 Clerk joined his friend George Croydon Marks in the firm of Marks and Clerk, consulting engineers and patent agents; this partnership lasted for the rest of his life. From 1892 to 1899 he was engineering director of Messrs Kynoch, of Birmingham, for whom he designed machinery for the manufacture of ammunition, and from 1902 he was a director and from 1929 until his death chairman of the National Gas Engine Company, of Ashton under Lyne.
Clerk began his work on the gas engine at the end of 1876. His first patent, taken out in 1877, was followed by a second in 1878, and in 1881 he patented an engine working on what became known as the Clerk (two-stroke) cycle, in which the main crankshaft received an impulse at each revolution, in contrast to the Otto (four-stroke) engine in which there was one impulse for each two revolutions. Engines of the Clerk type were manufactured in considerable numbers, but their popularity waned for a time after the lapse of the Otto patent in 1890. The Clerk cycle, however, came into extensive use for gas engines of the larger sizes.
Clerk's assiduous researches on the internal combustion engine, the specific heat of gases, and the explosion of gaseous mixtures won him an international reputation. He embodied his results in a book, The Gas Engine (1886), which subsequently appeared as The Gas, Petrol and Oil Engine (1909), and in many communications to scientific and technical societies, particularly the Institution of Civil Engineers, to which, between 1882 and 1928, he contributed five papers and two James Forrest lectures (1904 and 1920). The second of these lectures dealt with coal conservation in the United Kingdom and followed the theme of his Thomas Hawksley lecture to the Institution of Mechanical Engineers in 1915 on the world's supplies of fuel and motive power. In 1917 he delivered the first Trueman Wood lecture to the Royal Society of Arts.
During the First World War, Clerk was director of engineering research at the Admiralty (191617) and served on many committees concerned with the war effort. He was also chairman of the water power resources committee of the conjoint board of scientific societies (1917) and a member of the water power resources committee appointed by the Board of Trade in 1918. Other activities included chairmanship of the delegacy of the City and Guilds College, South Kensington, London (191819), and membership of the University Grants Committee and the Carnegie Trust for Scotland. He was frequently a judge at the reliability trials which were fashionable in the early days of the motor car.
Clerk, who was appointed KBE in 1917, received honorary degrees from the universities of Glasgow, Leeds, Liverpool, Manchester, and St Andrews. The Royal Society of Arts awarded him the Albert medal in 1922, and the Royal Society, of which he was elected a fellow in 1908, a royal medal in 1924. For the papers which he read before the Institution of Civil Engineers he received the Watt medal (1882), Telford prize (1882 and 1886), and Telford gold medal (1907). Ill health dogged his latter years; he died at his home, Lukyns, Ewhurst, Surrey, on 12 November 1932.
H. M. Ross, rev. John Bosnell
H. R. R., Obits. FRS, 1 (19325), 1012 · The Engineer (18 Nov 1932) · Engineering (18 Nov 1932) · PICE, 235 (19323), 5079 · W. A. Tookey, Sir Dugald Clerk and the gas engine, Journal of the Institution of Civil Engineers, 12 (19389), 2467 [lecture, abridged report] · Institution of Mechanical Engineers: Proceedings, 123 (1932) · Nature, 130 (1932), 9534 · CGPLA Eng. & Wales (1933)
A. S. Hartrick, pencil, crayon, and watercolour drawing, 1906, Scot. NPG [see illus.] · H. Speed, oils, 1910, Inst. CE · W. Stoneman, three photographs, 191727, NPG · photograph, repro. in H. R. R., Obits. FRS, facing p. 101
Wealth at death
£54,412 9s. 11d.: probate, 10 Feb 1933, CGPLA Eng. & Wales