Mr. John Ruskin, who has written of him and his works with intimate sympathy and inimitable charm. Even now, notwithstanding his reputation, he had to work hard for his living. His prices were one, three, or six guineas, according to the size of the drawing; and when, five years later, he raised his prices (apparently for the second time), on the plea that his health restricted his production, it was only from three and a half to four guineas, and to ten for the larger size. Some of these have since sold at prices ranging from five hundred to a thousand guineas. His last visit to Normandy was in 1846, and he returned from this in such a shattered state of health that he was obliged to withdraw from all society but that of his intimate friends. His cheerfulness and his industry were, however, indomitable. Though unable to begin work before the middle of the day, he would continue it till late in the night. In 1852 he was seized with apoplexy, and he died at Camberwell on 9 or 10 Feb. 1862.
A great many of the drawings of his continental period were lithographed and published in volumes. Among these were 'Facsimiles of Sketches made in France and Germany,' 1833; 'Interiors and Exteriors,' 1834; 'Sketches in France, Switzerland, and Italy,' 1839; and 'Sketches at Home and Abroad,' 1844. He also published 'Bits for Beginners;' 'Hints on Light and Shade, Composition, &c.,' 1838, republished 1848; 'Prout's Microcosm;' and an 'Elementary Drawing-book.' Engravings from his drawings are scattered in Pye's pocket-book series, the 'Landscape Annual,' 'Continental Annual' (1832), 'Forget-me-Not' (1826-34 and 1836-8), 'Keepsake' (1830-2), 'Fisher's Drawing-room Scrap-book' (1832-4), and other publications.
[Roget's 'Old' Water-colour Society; Ruskin's Notes on Prout and Hunt; Art Journal, March 1849 (Ruskin); Mrs. Hall's Retrospect of a Long Life; Athenæum, 14 Feb. 1852; Ackermann's Repository; Somerset House Gazette, ii. 47-8; Mag. of Fine Arts, i. 121-2; Monkhouse's Earlier English Water-colour Painters; Redgrave's Dict.; Bryan's Dict. (Graves and Armstrong).]
PROUT, WILLIAM (1785–1850), physician and chemist, was born on 15 Jan. 1785 at Horton, Gloucestershire, whcre his family had been settled on their own property for some generations. His early education was neglected, but he graduated M.D. at Edinburgh on 24 June 1811 with a thesis on intermittent fevers. He was admitted L.R.C.P. on 22 Dec. 1812, and settled in London. He had devoted himself from an early age to chemistry, and in 1813 delivered a course of lectures on this subject at his house in London to a small audience, which included Sir Astley Paston Cooper [q. v.] Of physiological chemistry he was one of the pioneers, and began in 1813 to publish investigations in this subject. In 1815, in an anonymous memoir on the 'Relation between the Specific Gravities of Bodies in their Gaseous State and the Weights of their Atoms,' Prout pointed out that there were grounds for believing that the atomic weights of all the elements are exact multiples of either the atomic weight of hydrogen or half that of hydrogen; and revived the view that hydrogen corresponds to the πρώτη ύλη of the ancients (Thomson, Annals of Philosophy, 1815 vi. 321, 1816 vii. 111). He supported his view by the publication of a few not particularly satisfactory experiments; but he made many others. In 1831 he suggested that hydrogen itself may be formed from 'some body lower in the scale' (Letter quoted in Daubeny's Atomic Theory, 2nd edit. p. 471). The view with regard to the atomic weights is known as Prout's 'hypothesis' or 'law'.
In 1815 Prout discovered that the excrement of the boa-constrictor contains 90 per cent. of uric acid, a fact of considerable physiological importance, and in 1818 he prepared pure urea for the first time (Thomson, Annals, x. 352). On 11 March 1819 Prout was elected F.R.S. on the proposition of Alexander Marcet, William Hyde Wollaston [q. v.], and others. In 1820 he wrote that he had analysed 'almost every distinct and well-defined substance' to be found in organised bodies. In 1821 he published his 'Inquiry into … Gravel, Calculus, and other Diseases of the Urinary Organs,' which he recast in a third edition in 1840, under the title 'On … Stomach and Urinarv Diseases;' this was republished in 1843 and 1848. The treatise, which is of value, is practical, and contains little speculation (Daubeny). On 23 Dec. 1823 he announced his classical discovery of the existence in the stomach of free hydrochloric acid, a most important factor in digestion. Of his scientific papers, which mostly deal with the chemistry of the blood and the urine, the last appeared in 1829, and he henceforward devoted himself chiefly to medical work and practice. On 28 June 1829 he was admitted F.R.C.P. In 1831 he delivered a course of Gulstonian lectures on the 'Application of Chemistry to Physiology, Pathology, and Practice,' which were reported in the 'London Medical Gazette,' and led to a heated controversy in the same journal (vols. viii. and ix.) with Dr. Alexander Philip Wilson Philip [q. v.] (Munk). In 1834 Prout published as a Bridgewater