Dictionary of National Biography, 1927 supplement/Darwin, George Howard

DARWIN, Sir GEORGE HOWARD (1845–1912), mathematician and astronomer, was born at Down, Kent, 9 July 1845, the second son of Charles Darwin, the naturalist [q.v.], by his wife, Emma, daughter of Josiah Wedgwood. He was descended on both sides from men of intellectual and scientific distinction. His eminent father, his grandfather, Robert Waring Darwin, a physician, and his great-grandfathers, Erasmus Darwin [q.v.], physician, poet, and philosopher, and Josiah Wedgwood of Etruria [q.v.], the originator of the famous Wedgwood pottery, were all fellows of the Royal Society. At the age of eleven Darwin was sent to Clapham grammar school, then kept by the Rev. Charles Pritchard [q.v.], afterwards Savilian professor of astronomy at Oxford, who catered specially for scientific families by putting more mathematics and science into his curriculum than was then to be found at the great public schools. Having competed unsuccessfully for an entrance scholarship at St. John’s College, Cambridge, in 1863, and again at Trinity in 1864, Darwin entered Trinity in the autumn of 1864 without a scholarship, and read mathematics with Edward John Routh [q.v.], the well-known ‘coach’. Two years later Trinity elected him to a foundation scholarship, and in January 1868 he graduated as second wrangler and was awarded the second Smith’s prize. The autumn of the same year saw him elected a fellow of his college.

Although Darwin had generally been expected to do well in his examinations, no one, and least of all himself, had so far recognized that he possessed quite exceptional mathematical ability, and his place in the tripos was higher than he had ventured to hope for. Having at this time no idea of finding his life’s occupation in mathematics or science, he began reading for the bar; he was called in 1874, but he never practised. His health, which had frequently given trouble in his boyhood, grew much worse after he had taken his degree, and he began to suffer seriously, as his father had done before him, from digestive troubles and general weakness. Successive treatments at Malvern, Homburg, and Cannes produced no cure, although from 1873 onwards he gradually improved under the care of (Sir) Andrew Clark.

This period of ill-health resulted in Darwin’s abandoning all thought of a legal career; and in October 1873 he returned to Cambridge and settled in rooms in Trinity. At this time he was writing articles on oddly miscellaneous subjects, such as ‘Development in Dress’, ‘Restriction to Liberty of Marriage’, a ‘Defence of Jevons’, and ‘Cousin Marriages’. About 1875 a more distinctly scientific trend became noticeable, in papers on slide-rules, equipotential lines, elliptic integrals; and finally the memoir On the Influence of Geological Changes on the Earth’s Axis of Rotation, read before the Royal Society in 1876 and published in the Society’s Philosophical Transactions (1877), marked his definite entry into serious scientific life. He was proposed for the Royal Society in 1877 and elected a fellow in 1879. After his Trinity fellowship had expired (in 1878) he continued to live in Cambridge, holding no official position but pursuing research on cosmogony. In 1883 the Plumian professorship of astronomy and experimental philosophy fell vacant through the death of James Challis [q.v.], and Darwin was elected, although only, if we may trust a note in his diary, by the votes of five out of the nine electors. In 1884 he married, and his family life was conspicuously happy in spite of the continual handicap of his indifferent health.

The main part of Darwin’s scientific life was occupied by lines of research which originated out of his memoir of 1876. Sir William Thomson (afterwards Lord Kelvin) had been asked by the Royal Society to report on the suitability of this paper for publication; and out of the ensuing correspondence and conversations resulted a friendship which terminated only with the death of the older man, as well as a lifelong devotion of the younger to problems of the past history of the earth and of the solar system. Generally speaking, Darwin’s earliest papers dealt solely with the earth; those of his next epoch were concerned with the earth-moon system; later papers survey the whole solar system and even to some extent the whole universe of stars, but always with reference to the problems of past history and development. The object of most of these papers is to put general conjectures to the test of precise numerical calculations. The method is well illustrated in his 1876 paper already mentioned. Geologists, impressed by the apparent evidence of successive ice-ages, and naturalists, arguing from the present and supposed past distributions of terrestrial life, had promulgated the hypothesis of former extensive wanderings in the position of the earth’s pole and violent variations in the obliquity of the ecliptic. Darwin showed, by numerical calculation, that so long as the earth has remained rigid, the north pole can never have been distant more than about 3° from its present position. The possibility of cataclysmic adjustments of the earth’s shape may somewhat increase this figure, but in no event is a change to the extent assumed by geology dynamically possible.

The next series of papers, on the earth-moon system, are marked by the hypothesis that ‘tidal friction’ played a prominent part in the development of the system. As a result of viscosity, the tides raised in our earth by the moon will always have their points of high tide a little in advance of the positions they would occupy if the whole earth were perfectly fluid. The result is a force ever checking the speed of the earth’s rotation and increasing the distance between the moon and the earth, with a consequent lengthening of the month. Tracing this effect back into the past Darwin arrived at a stage, 54 million years ago or more, at which the moon was only about 6,000 miles from the earth’s surface, while the two bodies rotated together, each always turning the same face to the other. The day and month, at this time equal, were each rather less than a quarter of our present day. He concluded that the earth and moon must originally have formed a single mass, and he was led to study the process by which this mass had broken up.

A further application of the theory of tidal friction to the motion of the planets round the sun opened up the wider question of the genesis of the solar system. Darwin had at first believed that tidal friction would account for the evolution of the whole solar system, but he subsequently adopted the view that tidal friction had been of primary importance only in the one case of the earth-moon system, which he consequently supposed to form a unique example in the solar system of this special method of evolution. At this time the generally accepted theory of the origin of the planets and their satellites was that propounded by Laplace, according to which each planet and satellite had been formed by the condensation of a ring of matter shed by the primary body around which it revolved. Darwin’s researches led him to contemplate the simpler possibility of an astronomical body breaking directly into two detached masses, and he tried to reconstruct the details of the process by tracing back the history of such a pair of bodies as our earth and moon still farther than had already been done. In the meantime Jules Henri Poincaré was attacking the same problem from the other end, examining the sequence of events in a mass which, owing to continued shrinkage, was rotating so fast that it could no longer hold together as a single body. Darwin adopted Poincaré’s line of attack with enthusiasm, and devoted much of the last period of his life to this problem. He was still at work on it at the time of his death, which took place at Cambridge 7 December 1912.

Although the main stream of Darwin’s work was always associated with the evolution of the solar system, yet no small part of his time was spent on quite other problems, many of which were brought to his notice through his membership of various scientific committees. He dealt, as a recognized authority, with a very wide range of subjects, including tidal theory, geodesy, and dynamical meteorology. Of the four large volumes in which his collected works are published [Scientific Papers by Sir George Howard Darwin, 1907-1911], the first is devoted entirely to Oceanic Tides, while the fourth and largest is entitled Periodic Orbits and Miscellaneous Papers. When invited to deliver a course of lectures in Boston, U.S.A., in 1897, he chose as his subject ‘The Tides’. The lectures were subsequently published (1898) in a book which is a masterpiece of semi-popular scientific exposition; it passed through many editions in English, as well as two in German, and has also been translated into Italian, Spanish, and Hungarian.

To the end of his life Darwin’s personality suggested a certain boyish eagerness; he seemed always on the look-out for adventures. He conveyed no suggestion of midnight-oil; his own estimate of his average hours of work was only three a day. That he achieved so much must be ascribed first to a flair for starting each problem in the right way, and secondly to an obstinacy which insisted on probing every problem to the bottom. He lost no time over false starts. His mathematical technique was simple; his method was always that of the direct frontal attack; his skill was of a type which he described just before his death, although with undue self-depreciation, as similar to the skill ‘of a house-breaker who blows in a safe-door with dynamite instead of picking the lock’. Probably his special ability lay in getting his problem set out in perfect order before the dynamiting process began. As a lecturer and speaker he gave a quiet impression of reserve power; his pronouncements being entirely free, as was his whole character, from anything of the nature of display or self-consciousness. His unassuming modesty, no less than his personal charm and eagerness, endeared him to all who met him. He gave his time and energy freely to service on various scientific committees, being especially attracted by such as connected his university or country with the wider world. He acted with conspicuous success as president of the British Association on the occasion of its visit to South Africa in 1905 and was created K.C.B. on his return. In 1909 he presided over the International Geodetic Association, and in 1912, three months before his death, over the International Congress of Mathematicians. His scientific eminence was recognized by numerous honours and by membership of most of the leading scientific societies of the world.

Darwin married in 1884 Maud, daughter of Charles du Puy, of Philadelphia, U.S.A., by whom he had two sons and two daughters. The eldest son, Charles Galton Darwin, has followed with distinction his father’s career of applied mathematics.

There is a portrait of Darwin by Mark Gertler in the National Portrait Gallery, which was painted in 1912 and presented by Lady Darwin in 1923.

[Sir Francis Darwin, Memoir of Sir G. Darwin in vol. v of Scientific Papers by Sir George Howard Darwin, 1916; obituary notices in Proceedings of the Royal Society, vol. lxxxix, A, 1913-1914, and in Monthly Notices of the Royal Astronomical Society, vol. 73; Francis Galton and Edgar Schuster, Noteworthy Families, 1906; Emma Darwin: A Century of Family Letters (1792-1896), edited by Henrietta Litchfield; Life and Letters of Charles Darwin, edited by Francis Darwin, 8 vols., 1887; personal knowledge.]

J. H. J.