by D. J. Wright
© Oxford University Press 2004 All rights reserved
Bryan, George Hartley (1864-1928), applied mathematician, was born on 1 March 1864 at 12 Trumpington Street, Cambridge, the only child of Robert Purdie Bryan, fellow-commoner of Clare College, and his wife, Fanny, daughter of George Martell, a surgeon. His father died in 1865 at the age of twenty-five while a student of law and Bryan's subsequent upbringing and education were undertaken by his mother and grandparents.
An only child and in delicate health, Bryan had an indulgent childhood, the family spending much of its time abroad in France, Italy, and Germany, especially the warmer climes of the Italian and French rivieras. This unusual upbringing gave him an excellent knowledge of languages and a lifelong fascination with the natural world, particularly of the rivieras, but it also led to a rather noticeable personal eccentricity. He was never allowed to go to school, and even when he became an undergraduate at Peterhouse, Cambridge, in 1883 he still lived at home. Having graduated as fifth wrangler in the mathematical tripos of 1886, in the next year Bryan was placed in the first division of the first class in part two of the tripos and in due course was second Smith's prizeman. He was elected a fellow of Peterhouse in 1889, his fellowship terminating automatically in 1895. In 1896 he was appointed professor of pure and applied mathematics at the University College of North Wales, Bangor, a position he held, with a special period of leave for research in 1917-20, until his retirement in 1926. His eccentric and absent-minded behaviour gave rise to numerous anecdotes among the Bangor students of the time. Bryan was elected a fellow of the Royal Society in 1895 and honorary fellow of Peterhouse in 1915. On 17 July 1906 he married Mabel Williams (1870-1958), headmistress of the Bangor kindergarten school. Their only daughter, Margaret, was born in 1909.
Bryan's unique and lasting contribution to mathematics was the formulation of the theory of aircraft stability. As early as 1896 he recognized the importance of stability and control when addressing the Royal Artillery Institution on progress in manned flight. In June 1903, even before the first powered flight by the Wright brothers, he and his former student W. E. Williams communicated an epoch-making paper to the Royal Society on the longitudinal stability of gliders. Once certain characteristic quantities related to an aircraft were known, it became possible to study mathematically its stability--though only (at this stage) in the direction of its flight. Early aviators constructed their machines empirically and Bryan's work had little impact. However, persevering in his efforts, he published Stability in Aviation in 1911, completing the mathematical treatment of aircraft stability in all dimensions. Soon, using wind tunnels, the necessary characteristics of an aircraft could be experimentally evaluated and Bryan's theory became an integral part of all aircraft design. In 1914 his work was recognized by the award of the gold medal of the Royal Aeronautical Society. He was also elected president of the Institution of Aeronautical Engineers.
Stability was a recurring theme in Bryan's work. His first papers in 1888 were on the stability of elastic systems and the stability of a rotating cylinder of liquid, but he spread his very considerable and highly productive talents in applied mathematics widely. In 1891 and 1894 he produced important reports for the British Association on thermodynamics (the study of the general laws governing heat and energy), becoming a world authority on the subject. The article on thermodynamics published in the Encyklopädie der mathematischen Wissenschaften (1898-1934) is his. His 1900 paper on the mathematical theory of the action of bilge keels in extinguishing the oscillations of a ship led, in 1901, to the award of the gold medal of the Institution of Naval Architects.
Bryan was committed to raising the standards and status of mathematical education in Britain, and produced, mainly with W. Briggs, over a dozen student textbooks, such as the Elementary Text Book of Mechanics of 1894. In 1907, while president of the Mathematical Association, he introduced local branches by setting up the first in north Wales.
Bryan was an accomplished naturalist, contributing many articles on botany, entomology, and microscopy to such journals as Science-Gossip and the International Journal of Microscopy and Natural Science. He served as president of the Cambridge Entomological Society and the Postal Microscopical Society. A man with very wide interests, his great love of music led him to experiments with pneumatic piano-players on which he published a paper in the Proceedings of the Royal Institution (21, 1915, 397-406). On retirement in 1926 Bryan moved to his beloved Italian riviera. He died, after a short illness, at his villa, Le Lucciole, in Bordighera on 13 October 1928.
D. J. WRIGHT
Sources
S. Brodetsky, Nature, 122 (1928), 849-50
A. E. H. Love, Journal of the London Mathematical Society, 4 (1929), 238-40
F. Hacker, Flight stability and control (1970)
b. cert.
m. cert.
d. cert.
CGPLA Eng. & Wales (1928)
Archives
U. Wales, Bangor, archives
Wealth at death
£8238 10s.: probate, 13 Dec 1928, CGPLA Eng. & Wales
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