Page:Dictionary of National Biography volume 14.djvu/337

  he was appointed to three remunerative offices in the custom house, and in 1768, upon the king's erecting an observatory at Kew, specially with a view to the transit of Venus in the following year, Demainbray was appointed astronomer there, an office which he retained until his death, at the age of seventy-two, 20 Feb. 1782. He was buried at Northolt, Middlesex. He does not appear to have at any time contributed to philosophical journals, either in France or England, or to have been known as an author in any other way. Two short notices of his first electrical experiments were communicated by him to the ‘Caledonian Mercury’ in February 1746, which were reprinted in the ‘Scots Magazine.’ He was succeeded in the observatory at Kew by his son, Rev., B.D., of Exeter College, Oxford, who retained the post of astronomer there for the long period of fifty-eight years, until in 1840 that observatory was given up. During the earlier part of this period he was assisted by the husband of his half-sister Mary, Stephen Rigaud, and after the latter's death in 1814 by his son, Stephen Peter Rigaud, M.A., of Exeter College, the Savilian professor and Radcliffe observer at Oxford. Demainbray (who was royal chaplain for fifty-two years, 1802 till death) retired on a pension, and died at his rectory of Somerford Magna, Wiltshire (which he held from 1799), on 6 July 1854, aged 95. He was the author of a very sensible and practical pamphlet on village allotments, giving the results of twenty-four years' experience, when as yet such allotments were not common. It was published in 1831 as a letter to the Marquis of Salisbury, under the title of ‘The Poor Man's Best Friend.’



DE MOIVRE, ABRAHAM (1667–1754), mathematician. [See .]

DE MORGAN, AUGUSTUS (1806–1871), mathematician, son of Colonel De Morgan of the Indian army, was born at Madura, in the Madras presidency, in 1806. His mother was daughter of John Dodson of the custom house, and granddaughter of [q. v.], author of the ‘Mathematical Canon.’ Seven months after De Morgan's birth his parents sailed for England with their three children. They settled at Worcester. Colonel De Morgan was again in India from 1808 to 1810, when he returned, and satisfactorily proved his innocence of some charges arising from the insubordinate state of the Madras army. He lived with his family in Devonshire, settling at Taunton in 1812. Thence he returned to India, was invalided in 1816, and died at St. Helena on his way to England. The elder De Morgans were of strict evangelical principles. The father began the education of his son and inculcated religious dogmas and practices at a very early age. The mother, who survived till 1856, continued the same discipline. De Morgan was sent to various schools, one of his teachers being J. Fenner, a unitarian minister and an uncle of H. Crabb Robinson. His last schoolmaster was the Rev. J. P. Parson of Redlands, Bristol, to whom he was sent in 1820. He is described as a fine stout boy. He had lost one eye in his early infancy. This exposed him to cruel practical jokes till he gave a ‘sound thrashing’ to his tormentor, and it prevented him from joining in the usual games. He had a gift for drawing caricatures, and read algebra ‘like a novel.’ He pricked out equations on the school-pew, some of which remained after his death, instead of listening to the sermon. In February 1823 he entered Trinity College, Cambridge, as a ‘bye-term man.’ He soon showed his mathematical ability, and in his second year was easily first in the first class. He made many friends at college, including his teachers, Whewell and Peacock. He belonged to a musical society called the ‘Camus’ (i.e. Cambridge Amateur Musical Union Society), and was a skilful flute-player. He had an insatiable appetite for novels, and often sat up reading till the early morning. In 1827 he graduated as fourth wrangler, though far superior in mathematical ability to any man in his year. He was disappointed by the result, which was due to his discursive reading. He retained through life a strong dislike to competitive examinations as tending to give the advantage to docile over original students, and to encourage ‘cram.’ His mind had further been distracted by metaphysical readings, especially in Berkeley's works, and by theological speculation. Even at school he had revolted from the doctrines held by his mother, and at Cambridge he became heterodox. He was through life a strong theist, and preferred the unitarian to other creeds, but never definitely joined any church, calling himself a ‘christian unattached.’ He refused to carry out his mother's wishes by taking orders, and his scruples prevented him from proceeding to the M.A. degree or becoming a candidate for a fellowship. After some thoughts of medi-