The bill, however, passed the house of peers without a division (7 April 1720). A question addressed by Cowper to the ministry concerning an absconding cashier of the South Sea Company on 23 Jan. 1721 appears to be the earliest recorded instance of a public interpellation of ministers. On 13 Dec. he moved the repeal of certain clauses of the Quarantine Act; on 11 Jan. 1722 he called attention to ‘the pernicious practice of building ships of force for the French,’ and moved that the judges should be ordered to introduce a bill to put an end to it. On 3 Feb., the lord chancellor being two hours late and the lord chief justice, who was commissioned to take his place on the woolsack in his absence, not being present, Cowper moved that the house proceed to elect a speaker ad interim. The lord chancellor then arriving excused himself on the ground that he had been detained by the king in council at St. James's. This excuse the lords refused to accept, and entered a lengthy protest in the journal of the house (signed by Cowper) in which they affirmed that the house was ‘the greatest council in the kingdom, to which all other councils ought to give way.’ On 26 Oct. Cowper opposed the committal of the Duke of Norfolk to the Tower on suspicion of treason. An assertion by the Jacobite conspirator Layer, in the course of his examination before a committee of the House of Commons in January and February 1723, that he had been informed that Cowper was a member of a club of disaffected persons known as Burford's Club, elicited from Cowper a public declaration of the entire groundlessness of the charge. The bill of pains and penalties against Atterbury was earnestly opposed by Cowper, who closed the debate with a solemn protest against the exercise of judicial powers by parliament without the formal proceeding by impeachment (15 May 1723). He also opposed Walpole's bill for ‘laying a tax upon papists’ (20 May). On 5 Oct. 1723 he took a severe cold while travelling from London to his seat in Hertfordshire, of which he died five days later. He was buried in Hertingfordbury church. Ambrose Philips celebrated his virtues in an ode styled by courtesy ‘Pindaric’ (Chalmers, English Poets, xiii. 121). The Duke of Wharton in the ‘True Briton’ (No. 40) magnified his genius and extolled his virtue in terms of the most extravagant eulogy. Pope (Imitations of Horace, epist. ii. bk. ii.) and Lord Chesterfield agree in describing him as a consummate orator. His person was handsome, his voice melodious, his elocution perfect, his style pure and nervous, his manner engaging. On the other hand, in logical faculty and grasp of legal science he was deficient. Steele dedicated the third volume of the ‘Tatler’ to him, and an enthusiastic panegyric upon him under the name of ‘Manilius,’ written by his humble friend Hughes at the time when there was least to expect from his patronage (1712), fills one number of the ‘Spectator’ (No. 467). He was F.R.S., governor of the Charterhouse, and lord-lieutenant of Herefordshire 1700–2 and 1714–22. By his first wife he had one son only, who died in boyhood; by his second wife he had two sons (William, who succeeded to the title, and Spencer [q. v.], who took holy orders and became dean of Durham) and two daughters. Two of his speeches in passing sentence on the rebel lords were printed in pamphlet form in 1715 (Brit. Mus. Cat.), and a few of his letters will be found in ‘Letters by several Eminent Persons,’ London, 1772, 8vo (Brit. Mus. Cat.), and in the ‘Correspondence of John Hughes,’ Dublin, 1773, 12mo (Brit. Mus. Cat.), others in Addit. MSS. 20103, ff. 7–33, and 22221, f. 256.
[Cowper's Private Diary (printed in 1833 and presented to the Roxburghe Club by Ed. Craven Hawtrey) covers the period from 1705 to 1714; it consists chiefly of brief minutes of cabinet councils and jottings of private conversations with politicians; it becomes very slight and fragmentary after his surrender of the seal. Lady Cowper's Diary (edited by the Hon. Spencer Cowper, London, 1864, 8vo) begins where her husband's leaves off, but is only continuous for two years [see Cowper, Mary, 1685–1724]. Other sources of information are: the obituary notice in the Chronological Diary, appended to the Historical Register for the year 1723; Berry's County Genealogies (Hertfordshire), p. 168; Clarke's Life of James II, ii. 590; Rapin (Tindall), 2nd edit. ii. 713; Lists of Members of Parl. (Official Return of), i. 542, 547, 559, 566, 574, 581, 586, 594, 600, ii. 2; Clutterbuck's Hertfordshire, ii. 192; Burnet's Own Time (Oxford ed.), iv. 480 note, v. 220, 248, 299, vi. 11 note, 31 note, 76 note; Additional Annotations, p. 145; Howell's State Trials, xii. 1446–7, xiii. 123, 199, 219, 246, 272, 274, 422, 465, 471, 494–5, 498–9, 501–2, 504–5, 509–12, 515, 521, 555, 623, 742–44, 1035, 1055, 1091, 1198, xv. 466–7, 847, 893, 1046–1195; Luttrell's Relation of State Affairs, iv. v. vi.; Parl. Hist. v. 1227, vi. 279–85, 546, 826, 887, 961–5, 1039, 1060, 1146, 1256, 1330, 1331, 1337–1338, 1351–5, 1364; vii. 42–6, 104, 111, 224, 305, 541, 569, 591–4, 606–24, 641, 709, 894, 933, 939, 960, viii. 44, 203, 334, 347, 363; Lords' Journ. xviii. 177; Coxe's Sir R. Walpole, ii.; Despatch of Lord Townshend to Secretary Stanhope, 2 Nov. 1716; Evelyn's Diary, ad fin.; Chron. Reg. appended to Hist. Reg. (1717), p. 46, (1718) p. 11; Voltaire's Dict. Phil. ‘Affirmation par serment;’ Welsby's Lives of Eminent Judges; Foss's Lives of the Judges; Collins's Peerage (Brydges), iv.]