proceeded to the continent for the purpose of studying medicine. At Paris he studied under Petit, and after visiting Rheims proceeded to Leyden, where he graduated M.D. on 20 Dec. 1752. The title of his thesis was 'De Gangræna et Sphacelo.' Не then visited Spa, Aachen, and other baths for the purpose of investigating the composition of their mineral waters. He returned to England in 1753, proceeding to Bath, and after a series of elaborate experiments conducted in public he went to London, where he established himself in practice. In 1756 he published 'An Essay on Waters. In three Parts: (i) of Simple Waters, (ii) of Cold Medicated Waters, (iii) of Natural Baths.' This treatise, reviewed by Dr. Johnson (Boswell, Life of Dr. Johnson, ed. Hill, i. 311), gave great offence to the faculty at Bath (see also Recueil d'observations des effets des Eaux Minerales de Spa … par J. P. de Limbourg, Liège, 1765), and having occasion to visit that place in 1757 he became involved in an acrimonious controversy with the heads of the profession there owing to their refusal to consult with him (see Letters of Dr. Lucas and Dr. Oliver, London, 1757). But the book obtained for him considerable reputation, and enabled him, it is improbably said (A Vindication of the Corporation of the City of Dublin, Dublin, 1766, p. 13), to make an annual income of 3,000l. by his profession. On 25 June 1759 he was admitted a licentiate of the College of Physicians of London. In view of the general election at the accession of George III, Lucas published in November 1760 a pamphlet entitled 'Seasonable Advice to the Electors … of Ireland in general, to those of Dublin in particular.' In the same month he determined to offer himself as a candidate for the city of Dublin, notwithstanding the consequent loss of his practice in London. After assuring himself that the electors of Dublin 'were warmed with the same sentiments in which he left them' (Charlemont MSS. i. 265, 269; Bedford Correspondence, ii. 427), he obtained a personal interview with the king in order to petition for pardon, and being favourably received was enabled to return to Dublin, 15 March 1761, on a nolle prosequi. His return was the occasion of great popular rejoicing; the order for his disfranchisement was annulled at the midsummer assembly of the corporation; and in July the degree of Doctor of Physic was conferred upon him by Trinity College, Dublin. During the election Lucas's colleague, Colonel Dunn, withdrew his candidature in order to insure Lucas's return, which was strongly opposed by the aldermanic party (see The Free Electors' Address to Colonel Dunn, with his Answer, and Lucas, An Address to the Free Electors of Dublin, May, 1761). After a thirteen days' poll he and Recorder Grattan, father of Henry Grattan, were elected, and he continued to represent the city till his death in 1771.
In parliament Lucas does not appear to have shone as an orator; but by assiduously bringing every question of importance before the public, he had the merit of reviving 'that constitutional connection which ought to subsist between the constituents and their representative' (Address of the Guild of Merchants, 13 Jan. 1766). On the first day of the session, 22 Oct. 1761, he obtained leave to bring in the heads of a bill for shortening the duration of parliaments, which he presented to the house on 28 Oct.; but on a motion to have it transmitted to England it was defeated by a majority of sixty-five. Shortly afterwards he presented the heads of two new bills for securing the freedom of parliament (Plowden, Historical Register, i. 352–4). In 1763 the 'Freeman's Journal,' a biweekly newspaper, was started by three Dublin merchants under the management of Henry Brooke (1703?–1783 [q. v.]) Lucas contributed to it from its commencement, sometimes anonymously (see a long article in the form of an address to Lord Halifax, 8 Oct. 1763), but generally under the signature of 'A Citizen' or 'Civis.' Small as were its literary merits, the paper enjoyed at first great popularity, owing to the gratuitous contributions of Lucas and its strenuous assertion of Irish protestant privileges (Madden, Hist. of Irish Periodical Literature). In 1766 Lucas unsuccessfully opposed a bill to prevent the exportation of grain, on the ground that certain alterations made in it by the English privy council were detrimental to the rights of the Irish parliament. He justified his conduct in 'An Address to the Lord Mayor and Citizens of Dublin,' and replied to further censure (see An Antidote to Dr. Lucas's Address) in 'A Second Address to the Lord Mayor.' Several guilds, and among them the Guild of Merchants, presented addresses of thanks to him, and it was even proposed to grant him a salary of 365l. a year out of the city treasury as a public acknowledgment of his services in parliament. The proposal was rejected by the aldermen, and its rejection led to a renewal of the old quarrel between them and the commons, and to fresh manifestations of public sympathy with Lucas (see Proceedings of the Lord Mayor and Aldermen, 17 Jan. 1766; A Vindication of the Corporation … respecting … Charles Lucas, Dublin, 1766; A Letter to