Frank Smithies was a precocious child who was fortunate to be educated privately, and at no expense, by W. H. Roberts, a retired woollen manufacturer with a passion for education. As a result he entered Edinburgh University at the early age of 15. Graduating at the top of the class at 19, he took the high road to Cambridge that had been taken by so many distinguished Scottish mathematicians, going to St John's College and taking his degree there with distinction in two years.

Smithies then began research under G. H. Hardy, perhaps the finest classical analyst of his time. Hardy did not like the trend towards abstraction, but encouraged Smithies to follow his own interests; he completed his thesis on integral equations in 1936. There followed two happy years in Princeton, working with John von Neumann and enjoying the mathematical company there. After that he returned to Cambridge, having been elected to a research fellowship at St John's in the previous year.

He spent the war at the supply ministry, working on problems of gunnery and helping to establish an important advi- sory service on statistical quality control.

After the war, he returned to Cambridge, where he dedicated his life to mathematics, to his college, and to the university. He was an outstanding teacher. His lectures were meticulously prepared and models of clarity.

He did little research himself after the war because his interest, he said, lay in the way that a subject hangs together rather than in the solution of particular problems. This made him a superb research supervisor: his students would be pointed to an area where he had a shrewd inkling that interesting problems existed, and he would then gently guide them as they went.

He had no fewer than 53 research students in all, many of whom themselves went on to senior academic posts.

Appointed a university lecturer in 1947, and Reader in 1962, Smithies provided loyal service to the university, serving twice as chairman of his faculty board, twice as chairman of the History and Philosophy of Science Syndicate and for 14 years as a Syndic of the University Press, where he was proud of creating links with the School Mathematics Project, which led to a flow of important school textbooks.

Outside Cambridge, Smithies served on the council of the London Mathematical Society, and as its secretary for three years, and was secretary of the International Congress of Mathematicians when it met in Edinburgh in 1958. He was elected Fellow of the Royal Society of Edinburgh in 1961.

Smithies retired in 1979, and took up with enthusiasm the history of mathematics, a subject that had fascinated him for many years but which he had not previously had sufficient time to work on. This culminated, to widespread delight, in the publication of his monograph Cauchy and the Creation of Complex Functional Theory in 1997, when he was 85. Cauchy is famous for introducing rigour into mathematical analysis, and with his monograph, Smithies introduced new standards of mathematical rigour into the history of mathematics.

Smithies married Nora Arone in 1945. She died in 1987. They had no children.

**Dr Frank Smithies, mathematician, was born in Edinburgh on March 10, 1912. He died on November 16, 2002, aged 90**.

Copyright (C) The Times, 2002