Died: 6 August 1947 in Dunedin, Glencairn, Simonstown, South Africa

William Thomson was educated at Perth Academy and then at the University of Edinburgh. He graduated with an M.A. and B.Sc. in 1878. In the same year he was appointed as an Assistant in Mathematics at Edinburgh University, a position he held until 1883. During his time in Edinburgh Thomson was an assistant to the professor who was, at that time, George Chrystal. When Thomson left Edinburgh in 1883, Allardice succeeded him as Chrystal's assistant.

In 1883 Thomson was appointed as Professor of Mathematics at Victoria College, Stellenbosch (later incorporated with the University of Stellenbosch). In 1895 Thomson moved out of the academic side of the university to become Registrar of the University of the Cape of Good Hope, Cape Colony. After 23 years in this post he moved to the University of South Africa, in Pretoria, again as Registrar. He remained in this position from his appointment in 1918 for four years until he retired in 1922. This was not the end of his career, however, for he served as Principal of Witwatersrand University, Johannesburg, from 1924 to 1928.

Thomson was an assistant at Edinburgh University when the Edinburgh Mathematical Society was founded in 1883 but he did not join the Society at this time, rather he joined in December 1888 when he was Professor of Mathematics at Stellenbosch, Cape Colony. He remained a member throughout his career. He was elected to the Royal Society of Edinburgh on 6 March 1882, his proposers being George Chrystal, Peter Guthrie Tait, Alexander Crum Brown, Sir William Turner.

An obituary, written by J M Watt, appears in the Royal Society of Edinburgh Year Book 1948/1949, pages 48-49. 

1. J M Watt, Sir William Thomson, Kt., M.A., B.Sc., LL.D., Royal Society of Edinburgh Year Book 1948/1949, 48-49.