'ambi-navigator' ship called the Kent was constructed for him, but did not turn out a success (Stanhope, Pitt, 11. 397-401). In 1795 the earl revived the project of Genevois, the pastor of Berne, for impelling boats with duck-feet oars, but the highest rate of speed attained was three miles an hour (cf Whitaker, Course of Hannibal, 1794,ii. 142; Mathias, Shade of Pope, 1799). Stanhope declared in the House of Lords on 21 May 1810 that he had invented 'a vessel 111 feet in length which drew only seven feet odd inches of water, and outsailed the swiftest vessel in the navy.' His specification 'respecting ships and vessels' was printed in 1807.
Many printing appliances devised by himself he placed at the public disposal, without any advantage to himself, and made solid contributions to the art of printing. His chief assistant in this department of mechanics was Robert Walker, an ingenious mechanician of Vine Street, Piccadilly, and Dean Street, Soho. He perfected a process of stereotyping which was acquired by the delegates of the Clarendon Press at Oxford in 1805 on the condition that they paid 4,000l. to the foreman and manager of his press, Andrew Wilson, of Wild Court, and stereotyping on this system became part of the general business of the press. They also acquired, but free from any payment, his iron hand-press, called the Stanhope press, and his system of logotypes and logotype cases. This system a few years later was introduced into the Oxford press; but his logotypes, like those of John Walter [q. v.] of the 'Times,' proved a failure. The first book printed by his process was 'An Abstract of the whole Doctrine of the Christian Religion. By J. A. Freylinghausen,' 1804. Long after these dates he persevered with his experiments, either at Wilson's office or at Chevening, where he kept a foundry of his own. Another invention he called 'pantatype printing, by which one hundred thousand impressions of an engraving could be taken, all proofs; that is to say, the last impression will be as perfect as the first '(Collectanea, Oxford Hist. Soc. 1896, iii. 365-412; Hansard, Typogmphia, p. 475; H. G. Bohn on Printing, Philebiblon Soc. iv. 90).
Stanhope published in 1806 his 'Principles of the Science of Tuning Instruments with Fixed Tones,' which was reprinted in Tilloch's 'Philosophical Magazine' (xxv. 291-312). The invention formed the subject of numerous articles by John Farey and Stanhope in that magazine, and of Dr. Callcott's 'Plain Statement of Earl Stanhope's Temperament.' In 1779 he produced his 'Principles of Electricity,' but a second volume which he promised, in refutation of the conclusions drawn from the experiments of Benjamin Wilson, was not published. In the first volume and in the 'Philosophical Transactions' (lxxvii. 130) he contended that when a large cloud is charged with electricity it drives out a considerable portion of the electricity in its neighbourhood, which often returns to its original position with such violence and in such quantity as to destroy life. In this way he explained the death of a carrier and his horses at Berwickshire in 1787, though there was no discharge of thunder nearer than some miles distance (Thomson, Royal Soc. pp. 449-50). A public trial of Franklin's and Stanhope's experiments in lighting-conductors is said to have taken place at the Pantheon under the superintendence of Edward Xairne the electrician.
About 1777 Stanhope constructed two calculating machines (1) for working out with exactness complicated sums of addition and subtraction; (2) for similar sums in multiplication and division. 'The Stanhope Demonstrator, an Instrument for performing Logical Operations,' employed his thoughts at intervals for thirty years. It has been fully described by the Rev. Robert Harley, F.R.S., in an article in 'Mind' (iv. 192-210), which was reprinted separately for private circulation.
Stanhope's other inventions include a microscopic lens which, like the printing-press, bears his name; a new manner of producing cement more durable than the ordinary mortar; an improved method of 'burning chalk, marble, and limestone into lime; 'an artificial slate or tile for excluding rain and snow; and a means of curing wounds made in trees. In conjunction with Robert Fulton, the American engineer, he projected a canal from his estate at Holsworthy in Devonshire to the Bristol Channel, with a novel system of inclined planes and with improved locks.
Stanhope's life was thus one of unremitting toil. He died of dropsy at Chevening, on 15 Dec. 1816, and was buried with marked simplicity in the family vault at that church on 24 Dec. In person he was tall and thin, with a high forehead and a countenance expressive of impetuosity. He was always very plain in his attire, and of late years his looks were pale and wan. A powerful voice and a vigorous gesticulation heightened the effect of his oratory. His sympathies were wide, his generosity was unbounded, and his views were much in advance of their time. In all that he did whether it was in politics or in science, he