William S.H. Cleghorne, son of Major John Pace Cleghorne, was educated in Broxburn, Scotland, and at the University of Edinburgh. He qualified as Bachelor of Science (BSc) and was admitted as an associate member (and many years later as a full member) of the Institution of Mechanical Engineers. Around 1906 he was a Carnegie research student (funded by the Carnegie Corporation of New York through the Carnegie Trust for Universities of Scotland) and as co-author with Professor F.G. Baily of Glasgow published a paper on "Some phenomena of commutation" (Journal of the Institution of Electrical Engineers, 1907), which dealt with armature currents in direct-current dynamos and motors.
In 1907 Cleghorne came to South Africa to take up an appointment as lecturer in mechanical engineering at the South African College. At the end of 1909 he resigned his post and moved to Johannesburg to become a lecturer in engineering at the South African School of Mines and Technology, under Professor John Orr*. Two years later, in November 1911, he was employed by the Department of Agriculture of the Union of South Africa and appointed as lecturer in engineering at the School of Agriculture at Potchefstroom. During the next two years he published some articles in the Agricultural Journal (Union of South Africa) on "Design and construction of piggeries" (1912), "The construction of cow-byres" (1912), "Suction gas plants and engines" (1912), and "The construction of silos in stone and brick" (1913).
While at Potchefstroom Cleghorne published a substantial book, Farm buildings and building construction in South Africa; a textbook for farmers, agricultural students, teachers, builders, etc. (London, 1916, 325 pp). A second edition appeared in 1922.
Cleghorne also became an external examiner in engineering design and drawing at the University of Cape Town (formerly the South African College) and in agricultural engineering at the Transvaal University College in Pretoria. At some time between 1917 and 1924 the University of Edinburgh awarded him the degree Doctor of Science (DSc). A comprehensive paper by him on "A study in charcoal: Being a research on charcoals made from exotic woods grown in the Union of South Africa" (Transactions of the Royal Society of South Africa, 1924, Vol. 11, pp. 23-45) was probably based on his doctoral research. During the next few years he invented a new type of ox-yoke and wrote "Yoking oxen to the plough: A new system" (Department of Agriculture, Science Bulletin No. 53, 1926), and some other contributions to agricultural engineering published by the Department of Agriculture.
Cleghorne became a member of the South African Association for the Advancement of Science in 1917. He later published papers in the South African Journal of Science dealing with "Some remarks on soil erosion and reclamation" (1931) and "Veld reclamation at Grootfontein" (1932, 1933).