John Patrick Dalton received his university education in Scotland, qualifying as Master of Arts (MA) at the University of St Andrews. He soon developed into a versatile academic of outstanding intellectual ability, with a forthright and combative nature. After two years as a researcher in thermodynamics at the University of Leiden, the Netherlands, and three years as a lecturer and demonstrator in physics at the University College, Dundee, Scotland, he came to South Africa in 1913 as lecturer in physics and applied mathematics at Victoria College, Stellenbosch. In 1914 the University of St Andrews awarded him the degree Doctor of Science (DSc), on the basis of which he was admitted also to the DSc degree of the University of the Cape of Good Hope (in 1915). His doctoral dissertation was titled Contributions to the knowledge of Van de Waal's equation, with additional papers.
In 1914 Dalton was appointed professor of mathematics at the South African School of Mines and Technology in Johannesburg. This institution became the University College, Johannesburg, in 1919 and in 1922 became the University of the Witwatersrand. When a Department of Actuarial Science was established around 1920, he initially also taught its students. In 1917 he was an examiner in mathematics for the University of the Cape of Good Hope.
Dalton became a member of the Royal Society of South Africa and in 1920 was elected on of its Fellows. He served on the society's council from 1923 and published several papers in its Transactions: "On van der Waal's equation" (1914/5), "On the integrated velocity equations of chemical reactions" (1921), "On the mathematics of the homogenous balanced action" (1924), "On the attraction coefficient for substances of low critical temperature" (1924), and "On integrating factors and Jacobi's equation" (1930). At a joint meeting of the university and the South African Institute of Electrical Engineers he presented a paper "On resonance", which was published in the institute's Transactions (1935). Two later papers, "On taxation and grade in gold mining: A study in inequalities" and "The mathematical problem of the price index", appeared in the South African Journal of Economics (1937). He also published some mathematical papers in overseas journals and books entitled An introduction to social insurance (1934) and Symbolic operators (1954). In 1915 he became a member of the South African Association for the Advancement of Science and in 1918, when the association held its annual congress in Johannesburg, served as joint secretary of Section A (which included mathematics).
Dalton was a compelling lecturer with wide interests and presented several public lectures to explain developments in the sciences. For example, during 1921 he gave a celebrated series of lectures on Einstein and the theory of relativity under the auspices of the University College of Johannesburg Scientific Society. These lectures were published as The rudiments of relativity (Johannesburg, 1921, 105 pp). He also gave lectures to the Transvaal Workers' Educational Association in 1933 on social insurance. Probably his most memorable public lecture was "The material world, yesterday and today", delivered in 1932, in which he rejected the holistic philosophy of J.C. Smuts*.
Dalton served in East Africa during World War II (1939-1945) and was honoured as an officer of the Order of the British Empire (OBE) in 1941. He retired from his post in 1946, settling at St Winnifred's, KwaZulu-Natal. He took his pension as a lump sum, but invested it unwisely and died in poverty. In 1910 he married Christina Stewart Dalton, born Cram, with whom he had three sons and a daughter.