William Nicholas Roseveare entered St John's College, University of Cambridge, in 1882 and was awarded the degree Master of Arts (MA). He was elected a fellow of the college in 1888. He was subsequently taught temporarily at King's College, London, and at Westminster School, and then became mathematics master at Harrow School, a prestigious school at Harrow-on-the-Hill, near London. While there he corresponded regularly with the British physicist Sir Joseph Larmor during 1893-1900. He also published some papers in the Mathematical Gazette, dealing with 'A chapter on algebra' (1903, in 2 parts), the convergence of series (1905), the expansion of trigonometrical functions (1905), and the expansion of functions in general (1905).
In 1906 Roseveare came to the Cape Colony and for a few years held temporary appointments at Stellenbosch and at Huguenot College, Wellington. In 1910 the University of the Cape of Good Hope admitted him to its MA degree on the basis of his degree from the University of Cambridge. That same year he was appointed as the first professor of pure and applied mathematics at the newly established Natal University College in Pietermaritzburg, arriving there in August 1910. He held this post until his retirement in either 1926 or 1930. In addition to teaching he served as both rugby coach (1913-1924) and cricket coach (1920-1921).
Roseveare was a member of the Royal Society of South Africa and published two papers in its Transactions, both in 1914, dealing with proofs that every equation has roots, real or imaginary, equal in number to its degree. In 1912 he became a member of the South African Association for the Advancement of Science, serving as president of Section A (which included mathematics) at the association's annual congress in 1917, and as joint vice-president of the association for 1917-1918. He contributed several papers to the annual Report of the association and its successor, the South African Journal of Science, dealing with 'Transition from elementary algebra to the calculus, without infinite series' (1915); 'On the gamma or factorial function' (1915); 'On equilateral triangles inscribed in ellipses, and regular tetrahedra inscribed in ellipsoids' (1916); and 'A short note on Einstein's planetary equation' (1920).
Roseveare was elected a Fellow of the Royal Astronomical Society in 1923. He was devoted to his small home-made observatory and was instrumental in having a 100 mm refractor telescope brought to Pietermaritzburg in the nineteen-twenties. The government astronomer Edmund Nevill* had used this telescope before it was given to the Durban Technical College in 1917 and subsequently entrusted to the Physics Department of the Natal University College. In 1927 Roseveare gave a highly successful public lecture on "The stars". He has been described as an 'able, absent-minded and lovable man' (Brooke, 1966, p. 28).