John Watson, technical chemist, metallurgist and assayer, was the son of John Watson senior. He was educated at the Kepier School, Houghton-le-Spring (near the city of Durham) and at the College of Science, Newcastle-on-Tyne. For several years he was on the staff of the Newcastle Chemical Works. Between 1888 and 1892 he published several papers in the Journal of the Society of Chemical Industry, on "A volumetric method for the rapid estimation of sulpher in burnt pyrites" (1888), "Estimation of available soda in commercial caustic soda" (1890), "The variation in the composition of caustic soda within the same drum" (1892), and "The use of Fuller's spiral slide-rule for chemical calculations" (1892). He became a Fellow of the Institute of Chemistry (FIC) by examination. In April 1894 he married Florence E. Cowper, with whom he had 2 children.
Watson came to South Africa in June 1896 and for 15? years worked as chemist and assayer to the City and Suburban Gold Mining Company, Johannesburg. Subsequently he went to India, where he worked for the Magadi Soda Company in Calcutta (now Kolkata). After his return to South Africa in December 1919 he became an analytical and consulting chemist in Johannesburg.
Watson became a member of the British Association for the Advancement of Science in 1889 and was still a member in 1905. In 1897 he joined the Chemical and Metallurgical Society of South Africa (from 1902 the Chemical, Metallurgical and Mining Society of South Africa), serving as a member of its council for 1913/14. Two papers by him were published in the society's Journal, "Assay of used plumbago crucibles for gold" (1910/1, Vol. 11, pp. 462-464) and "The natural soda deposits of Africa, with some notes on the alkali trade" (1913/4, Vol 14, pp. 235-241). In 1916 he participated in the discussion of a paper by P.A. Wagner*, delivered before the Geological Society of South Africa, on the origin of the salt pan north of Pretoria. He joined the South African Association for the Advancement of Science in 1918.