Melbourne ‘in the most urgent manner the necessity of gratifying O'Connell’ (Melbourne Papers, 1890, p. 167). He now wrote to Brougham urging him to secure the support of O'Connell and the leading Irish Roman catholics, assuring him that he was the only member of the cabinet who comprehended the Irish question; and adding, ‘most of your colleagues are not only ignorant of it, but, as it seems, incapable of understanding it’ (Life and Times of Lord Brougham, 1871, iii. 174–5). On 23 May 1832 Parnell called the attention of the house to the state of Queen's County, and moved for a select committee to inquire into the general efficiency of the law in Ireland for repressing outrages and disturbances (Parl. Debates, 3rd ser. xii. 1416–1417, 1428). He declined to contest Queen's County at the general election in December 1832, and on 27 March 1833 was appointed a member of the excise commission of inquiry (Parl. Papers, 1837, vol. xxx.). At a by-election in April 1833 he was returned for Dundee, which he continued to represent until his elevation to the House of Lords. In May 1835 he both spoke and voted against the government on the navy and the army estimates (Parl. Debates, 3rd ser. xxvi. 1041–2, xxvii. 348–9, 356). On the formation of Lord Melbourne's administration Parnell was appointed treasurer of the navy (22 April 1835) and paymaster-general of the forces (14 May 1835). By a treasury warrant of 1 Dec. 1836, under 5 and 6 Will. IV, c. 35, these offices were consolidated with those of the paymaster and treasurer of Chelsea Hospital and treasurer of the ordnance, and the duties transferred to a new official styled the paymaster-general, a position which Parnell filled until his death. On 15 March 1838 Parnell spoke in favour of the abolition of the corn laws, and declared that ‘there was no one interest in the country which derived any advantage from the corn laws but the landowners’ (Parl. Debates, 3rd ser. xli. 935–7, 939). In March 1839 and in May 1840 he again supported Mr. Villiers's motion (ib. 3rd ser. xlvi. 647–654, liv. 611–16). He spoke for the last time in the House of Commons during the debate on the sugar duties on 14 May 1841 (ib. 3rd ser. lviii. 439–45). He was created Baron Congleton of Congleton in the county palatine of Chester on 20 Aug. 1841, and took his seat in the House of Lords on the 23rd of the same month (Journals of the House of Lords, lxxiii. 572), but never took any part in the debates. After suffering for some time from ill-health, he committed suicide by hanging himself in his dressing-room in Cadogan Place, Chelsea, on 8 June 1842, and was buried on the 14th of the same month in the burial-ground of St. George's, Hanover Square, in the Bayswater Road, where in 1842 a tablet was erected in the chapel to his memory.
Congleton was an active and useful member of the most liberal section of the whig party. He was a fluent but monotonous speaker. He achieved a high reputation in his day, both as a political economist and as a writer on finance. In the art of giving a plain, lucid statement of complex financial matters he had few superiors. In his treatise on ‘Financial Reform,’ which had a considerable influence on public opinion, he laid before the country the financial and fiscal policy which Sir Robert Peel and Mr. Gladstone afterwards carried out (Sydney Buxton, Finance and Politics, 1888, i. 32, n.) Greville called him ‘a very bad secretary at war, a rash economical innovator, and a bad man of business in its details’ (Memoirs, 1874, 1st ser. ii. 243).
He married, on 17 Feb. 1801, Lady Caroline Elizabeth Dawson, eldest daughter of John, first earl of Portarlington, by whom he had three sons, viz.: (1) John Vesey, second baron Congleton [see below]; (2) Henry William, third and present baron Congleton; and (3) George Damer, vicar of Long Cross, Chertsey, from 1861 to 1875, who died on 17 Dec. 1882; and three daughters, viz.: (1) Caroline Sophia, who became the wife of Charles Thomas Longley [q. v.], archbishop of Canterbury, and died on 9 March 1858; (2) Mary Letitia, who was married, first, to Lord Henry Seymour Moore, and, secondly, to Edward Henry Cole of Stoke Lyne, Oxfordshire, and died on 6 May 1881; and (3) Emma Jane, who became the wife of Edward, fifth earl of Darnley, and died on 15 March 1884. Lady Congleton survived her husband many years, and died at Paris on 16 Feb. 1861, aged 78. A portrait of Congleton by Samuel Lane was exhibited at the loan collection of national portraits at South Kensington in 1868 (Cat. No. 319). Several of Congleton's speeches were separately published. He was the author of the following works:
- ‘Observations upon the State of Currency of Ireland, and upon the Course of Exchange between London and Dublin,’ Dublin, 1804, 8vo; 2nd edit. Dublin, 1804, 8vo; 3rd edit. (with additional appendix), 1804, 8vo.
- ‘The Principles of Currency and Exchange, illustrated by Observations on the State of Ireland, 1805; with an Appendix containing the Substance of the Evidence given before the Committee of the House of Commons,’ London, 1805, 8vo.
- ‘An Historical Apology for the Irish Catholics,’ 1807, 8vo.
- ‘A History of the Penal Laws against the Irish Catholics, from the Treaty of