Whittaker, Sir Edmund Taylor (1873–1956), mathematician, theoretical physicist, and director of Dunsink observatory, was born 24 October 1873 in Birkdale, near Southport, Lancs., eldest child of John Whittaker, railway engineer and contractor, and his wife Selina, daughter of Edmund Taylor, a physician practising in Middleton near Manchester. Before going to Manchester Grammar School in 1884, Whittaker was educated by his mother. He entered Trinity College, Cambridge, with a scholarship in 1892. His early interests were mainly in applied mathematics; in 1894 he won the Sheepshanks exhibition in astronomy. In the tripos of 1895 he was joint second wrangler.

Whittaker was elected a fellow of Trinity College, Cambridge, in 1896. His lectures on analysis formed the basis of *A course of modern analysis* (1902); G. N. Watson, who studied under Whittaker and later held a chair at Birmingham, shared the preparation of the second edition (1915), which added about 200 pages. Whittaker also taught courses on astronomy, geometrical optics, and electricity and magnetism. A major work on applied mathematics from the same period is *A treatise on the analytical dynamics of particles and rigid bodies* (1904). Both books have been regularly reprinted throughout the twentieth century. Among Whittaker's students were the mathematicians G. H. Hardy and J. E. Littlewood and the cosmologists A. S. Eddington and J. H. Jeans. Whittaker served as secretary of the Royal Astronomical Society 1901–6.

Following the premature death of C. J. Joly (qv) in 1906, Whittaker was appointed royal astronomer of Ireland and Andrews' professor of astronomy in the University of Dublin (TCD); he took up his duties in June. He had married (7 August 1901) Mary, daughter of the Rev. Thomas Boyd of Edinburgh. By 1906 they had two children; two more were born in Dublin and a fifth, later, in Edinburgh. A house near Dunsink observatory was provided for the family. As director of the observatory, Whittaker was responsible for a programme of stellar photography, in which he had the help of only a single assistant. Most of his research in 1906–12 is in theoretical astronomy; only two papers are about actual observations. He taught postgraduate courses on astronomical topics at TCD. Some of these contributed to his classical *History of the theories of aether and electricity from the age of Descartes to the close of the nineteenth century* (1910). Other lectures formed the basis of his tract *The theory of optical instruments* (1915).

Éamon de Valera (qv) was a student of Whittaker's in Dublin. Years later, during the second world war, de Valera consulted Whittaker about plans for the school of theoretical physics in the Dublin Institute for Advanced Studies, and Whittaker became one of its first board members.

In 1912 Whittaker was appointed professor of mathematics in the University of Edinburgh. He took a special interest in teaching and research in computational mathematics: a computing laboratory, the first of its kind in Britain, was opened at Edinburgh in 1913; Whittaker's lectures on numerical analysis are collected in *The calculus of observations: a treatise on numerical mathematics* (1924). The teaching of actuarial mathematics was another special interest. Whittaker became an increasingly prominent figure in the hierarchy of the university and served for a period as its acting principal. He attained the normal retirement age of 70 in 1943 but volunteered to remain in post for the duration of the war; he retired in 1946.

Whittaker published widely in pure mathematics: differential and integral equations and special functions are important themes; there are also papers on determinants and continued fractions. Much of his later work is in mathematical physics, especially electromagnetism and relativity. From about 1930 his purely scientific output declined, but he wrote extensively on historical, philosophical, and theological matters. His *History of the theories of aether and electricity* (1910) was revised and published in 1951, followed by a second volume in 1953. These volumes covered the period to 1926; a third volume (1926–50) was in preparation at the time of his death.

Honoured by learned societies, universities, church, and state, he was elected FRS in 1905 and was awarded the Sylvester medal (1931), the de Morgan medal (1935), and the Copley medal (1954); he was knighted in 1945. At various times he was president of the London Mathematical Society, the Royal Society of Edinburgh, the Mathematical Association, and section A of the British Association for the Advancement of Science. He held honorary degrees of seven universities and was an honorary member of several foreign academies. He wrote, in all, thirteen books and monographs, fifty-six papers in mathematics and physics, thirty-five articles on philosophy and history, and twenty-one biographical articles. Whittaker was deeply religious: he was received into the catholic church in 1930, having earlier belonged to several protestant denominations. Much of his later writing is about the impact of modern science on traditional theological arguments; his Donnellan lectures, given in Dublin in 1946, were published as *Space and spirit* (1947).

Whittaker died in Edinburgh on 24 March 1956, survived by his wife and their three sons and two daughters. His son John (1905–84) was professor of pure mathematics at Liverpool and from 1953 to 1965 was vice-chancellor of Sheffield University.