1653-4. Another account places his death some days later (see Cal. of Clarendon Papers, 1869, ii. 317). He was unmarried.
Cavendish was noted for his mathematical knowledge as well as for his love of mathematicians. Aubrey relates that 'he had collected in Italie, France, &c., with no small chardge, as many manuscript mathematicall bookes as filled a hoggeshead, which he intended to have printed; which if he had lived to have donne, the growth of mathematical! learning had been thirty yeares or more forwarder than 'tis.' His executor, an attorney of Clifford's Inn, dying, however, left the manuscripts in the custody of his wife, who sold them as waste paper. Cavendish was a great admirer of Rene Descartes and tried to induce him and Claude Mydorge to come to England that they might settle there under the patronage of Charles I. According to John Wallis (1616-1703) [q. v.], however, he convinced Giles Personne de Roberval that Descartes was indebted to Thomas Harriot [q. v.] in his additions to the theory of equations. In 1636 Mydorge sent Cavendish his treatise on refraction {Hist. MSS. Comm. Portland MSS. ii. p. 128), which was probably identical with his 'Prodromi catoptricorum et dioptricorum,' published in Paris three years later. Cavendish was also the friend of Pierre Gassend, William Oughtred [q. v.], and John Twysden [q. v.] According to John Pell [q. v.] 'he writt severall things in mathematiques for his owne pleasure.' A number of his letters to that mathematician are preserved among the Birch manuscripts in the British Museum, and some of them were printed by Robert Vaughan (1795-1868) [q. v.] in the second volume of his 'Protectorate of Cromwell' (1838) (where Cavendish is confused with his nephew. Lord Mansfield), and by James Orchard Halliwell [q. v.] in his 'Collection of Letters illustrative of the Progress of Science in England' (Hist. Soc. of Science, 1811). Cavendish was probably the author of some mathematical papers, formerly in the possession of John Moore (1616-1714) [q. v.], bishop of Ely, attributed by White Kennett [q. v.] to Sir Charles Cavendish [q. v.], brother of the Earl of Devonshire. His sister-in-law, the Duchess of Newcastle, dedicated to him her 'Poems and Fancies' (1653). A letter from Hobbes to Cavendish dated 1641 is in the Harleian MSS. (6796, f. 293), and another from Pell dated 18 Feb. 1644-5 is preserved in the same collection (ib. 6796, ft. 295-6).
[Life of William Cavendish, Duke of Newcastle, ed, C. H. Firth, 1886, index; Lloyd's Memoires, 1668, p. 672; Collins's Hist. Collections of Noble Families, 1752, pp. 24-5; Aubrey's Brief Lives, ed. Clark, 1898, i. 153-4, 366, 370, 386; Rigaud's Corresp. of Scientific Men, 1841, i. 22, 28, 29, 66, 87, 88; Calendar of Committee for Compounding, pp. 2021-3; Clarendon State Papers, iii. 34, 223; Berry's Gen. Peerage, p. 48; Hist. MSS. Comm. Portland MSS. ii. 126, 128; Sanford and Townsend's Great Governing Families, 1865, i. 144.]
CAVENDISH, Sir WILLIAM, seventh Duke of Devonshire, seventh Marquis of Hartington, tenth Earl of Devonshire, and second Earl of Burlington (1808–1891), born on 27 April 1808, in Charles Street, Berkeley Square, was the eldest son of William Cavendish (1783–1812), by his wife Louisa (d. 18 April 1863), eldest daughter of Cornelius O'Callaghan, first Baron Lismore. Lord George Augustus Henry Cavendish, first earl of Burlington (1754–1834), was his grandfather, and William Cavendish, fourth duke of Devonshire [q. v.], was his great-grandfather. He was educated at Eton and at Trinity College, Cambridge, graduating B.A. in 1829 as second wrangler and eighth classic, Henry Philpott [q. v.], afterwards bishop of Worcester, being senior wrangler. In the ensuing examination for the Smith's prizes the order of their names was reversed. He was also eighth in the first class of the classical tripos. He graduated M.A. in 1829, and received the honorary degree of LL.D. on 6 July 1835. On 18 June 1829 he was returned for the university to the House of Commons, where in 1831 and 1832 he supported the government proposals for parliamentary reform. He was, in consequence, rejected by the university at the election of 1831, but on 13 July was returned for Malton in Yorkshire. On 10 Sept. 1831 his grandfather was created Earl of Burlington, and he was henceforth styled Lord Cavendish. In the same year accepting the Chiltern Hundreds he succeeded his grandfather as M.P. for Derbyshire on 22 Sept., and on 24 Dec. 1832 he was returned for North Derbyshire, which he continued to represent until, on 9 May 1834, he succeeded his grandfather as second earl of Burlington. On 15 Jan. 1858 he succeeded his cousin, William George Spencer Cavendish, sixth duke of Devonshire [q. v.] From the time of his removal to the upper house Burlington abandoned politics and devoted himself to the scientific and industrial concerns of the country. On entering into possession of the ducal estates he found them heavily encumbered, and devoted himself to relieving them of their burdens. He showed himself an enlightened and
