when, his elder brother having been killed in a duel, he came into possession of the family estates. He was then (as described by Lady Morgan from her father's recollections) ‘a tall, elegant, comely young man,’ given to interlarding his discourse with foreign idioms. The morning after his marriage, in February 1757, with a daughter of Sir Thomas Blake of Menlo, co. Galway, he was thrown into prison for her debts. Yet they lived happily together for eight years, chiefly at Menlo, where Mrs. Kirwan died in 1765, leaving two daughters, of whom the elder married Lord Trimleston, the second Colonel Hill. In 1766 Kirwan, having conformed to the established church, was called to the Irish bar, but threw up practice after two years, and pursued scientific studies in London, exchanged for Greek at Cregg in 1773. He resided in London from 1777 to 1787, and became known to Priestley, Cavendish, Burke, and Horne Tooke. He corresponded with all the savants of Europe; his Wednesday evenings in Newman Street were the resort of strangers of distinction; the Empress Catherine of Russia sent him her portrait. His library, despatched from Galway to London on 5 Sept. 1780, was captured by an American privateer. Elected a fellow of the Royal Society on 24 Feb. 1780, he received the Copley medal in 1782 for a series of papers on chemical affinity (Phil. Trans. vols. lxxi–lxxiii.), promptly translated into German by Crell. His ‘Elements of Mineralogy’ (London, 1784; 3rd edition, 1810) was the first systematic treatise on the subject in English, and was translated into French, German, and Russian. ‘An Estimate of the Temperatures of Different Latitudes’ (London, 1787) was designed to pave the way for a theory of winds. As the representative work of the Stahlian school, Kirwan's celebrated ‘Essay on Phlogiston’ (London, 1787) was translated into French in 1788 by Madame Lavoisier, with adverse commentaries by Lavoisier, Monge, Berthollet, and De Morveau. Kirwan replied in a second English edition (1789), but in 1791 candidly acknowledged his conversion to the views of his opponents.
Delicate health compelling a more retired life, he settled in 1787 at No. 6 Cavendish Row, Dublin, joined the Royal Irish Academy, and became in 1799 its president. He presided as well over the Dublin Library and ‘Kirwanian’ Societies. A gold medal was voted to him by the Royal Dublin Society in acknowledgment of his services in procuring the Leskeyan cabinet of minerals for their museum, and his portrait by Hamilton hangs in their board-room. He was a member of the Edinburgh Royal Society and of a number of foreign academies; and the university of Dublin conferred upon him in 1794 an honorary degree of LL.D. A baronetcy offered to him by Lord Castlereagh was declined; but he bore the honorary title of inspector-general of his majesty's mines in Ireland.
Kirwan's criticism in 1797 of the Huttonian theory of the earth (Trans. R. Irish Acad. vi. 233) involved him in a heated controversy. The publication of his ‘Geological Essays’ (London, 1799), delayed by the Irish rebellion, was anticipated by the appearance of a German version. ‘An Essay on the Analysis of Mineral Waters’ (1799) indicated valuable methods and contained much useful information. He wrote instructively besides on subjects connected with mining, bleaching, and the chemistry of soils, and was consulted as a weather-prophet by half the farmers in Ireland. His ‘Logick’ (2 vols. London, 1807) and ‘Metaphysical Essays’ (1811) had little success.
An accomplished linguist, a brilliant talker, and an adept in Italian music, he indulged as he grew old in some minor oddities, readily permitted to the ‘Nestor of English chemistry.’ Even in courts of justice or at vice-regal levées he wore a slouched hat as a precaution against cold; received his friends, summer and winter, extended on a couch before a blazing fire; and, owing to a weakness of the throat, always ate alone, his diet consisting of ham and milk. Flies were his especial aversion; he kept a pet eagle, and was attended by six large dogs. He was a good landlord and philosophically indifferent to money. A unitarian form of belief was finally adopted by him, and he spent much time in scriptural study. He died, as the consequence of ‘starving out’ a cold, on 1 June 1812, in his seventy-ninth year, and was buried in St. George's Church, Lower Temple Street, Dublin. Between 1788 and 1808 he contributed thirty-eight memoirs to the ‘Transactions’ of the Royal Irish Academy; controverted in 1784 some of Cavendish's results (Phil. Trans. lxxiv. 154, 178); and presented to the Royal Society in 1785 ‘Remarks on Specific Gravities’ (ib. lxxv. 267) and ‘Experiments on Hepatic Air’ (ib. lxxvi. 118), the latter included, in an Italian translation, among Amoretti's ‘Opuscoli Scelti’ (x. 40, Milan, 1787). Several of his essays on chemical subjects were reproduced in German in Crell's ‘Annalen’ (vols. i. and ii., 1800). The Royal Irish Academy possesses a good likeness of him, and his portrait was also painted by Comerford. There is a bust of him in the Dublin Library.
