Page:Dictionary of National Biography volume 44.djvu/378

 Manchester Literary Club, by T. E. Bailey in 1876). Pepys wrote the parts 'unfit for publication' in French, and sometimes in Latin, Greek, or Spanish, and afterwards interpolated 'dummy letters,' as Mr. Mynors Bright discovered. The second edition appeared in 1828; a third, adding a fourth of the whole, in 1848; a fourth, with fresh notes, in 1854; other editions, as that in Bonn's Library (1857), are reprints of this. The edition by [q.v.], of which a third had never been printed before, appeared in 1875-9, in 6 vols. 8vo. Bright omitted about a fifth of the 'Diary,' but left a transcript of the whole to Magdalene College. The whole, except passages which cannot possibly be printed, has been finally published in 8 vols. 8vo (1893, &c.), edited by Mr. Henry B. Wheatley, F.S.A.



PEPYS, WILLIAM HASLEDINE (1775–1856), man of science, born in London on 23 March 1775, was the son of W. H. Pepys, a cutler and maker of surgical instruments in the Poultry, London; he was descended from Sir [q. v.] In March 1796 he helped to found the Askesian Society (see Life of W. Allen, pp. 26, 45), which eventually led to the foundation of the British Mineralogical and Geological Societies and the London Institution, of which he was one of the original managers, and honorary secretary from 1821 to 1824. His name appears as treasurer, and afterwards as vice-president, of the Geological Society in the first volumes of their ‘Transactions’ (beginning in 1811). He was also an early member of the Mineralogical Society. He appears to have succeeded to his father's business in the Poultry, and to have extended it to philosophical-instrument making. He was a close friend of (1770–1843) [q. v.], with whom he did most of his best work, and also was intimate with (1772–1864) [q. v.] Like these men, Pepys was a quaker. In 1798 he worked with Desvignes on soda-water apparatus (, Phil. Mag. iv. 358). In 1808 he was elected F.R.S. He took an active part in the management of the Royal Institution, of which he was president in 1816. He died at his house in Earl's Terrace, Kensington, on 17 Aug. 1856.

Pepys had remarkable skill and ingenuity in inventing apparatus, and many important devices are due to him. His mercury gasometer (suggested by a piece of apparatus of Watt's) and his water gasholder are still used in practically their original form. He was one of the first, if not the first, to use mercury contacts for electrical apparatus (ib. xli. 15) and tubes coated with indiarubber (ib. xi. 256) for conveying gases. In 1801 he connected the newly discovered voltaic pile with an electroscope and condenser of his own devising, and showed thus that ‘the electric and galvanic fluid possessed identity’ (ib. x. 38). The experiment had, however, been made previously by Volta (Philosophical Transactions of the Royal Society, 1800, p. 406). In 1807 he invented an ingenious eudiometer, which he calibrated by a method still used for the purpose (ib. 1807, p. 247; and Gasometry, translated by Roscoe, p. 29).

Pepys was in general rather occupied with the invention than the use of apparatus. His chemical work does not show originality. His most important researches were carried out with Allen. The experiments on the combustion of diamond, graphite, and charcoal, yielded a valuable confirmation of the results of [q. v.], Guyton de Morveau, and Mackenzie (, Gesch. der Chemie, iii. 292); and the very careful and well-reasoned work on respiration, executed with apparatus for the most part invented previously by Pepys, and allowing the experimenters to repeat the investigation of Lavoisier and Séguin more accurately and with some variations, is still quoted in the textbooks. The chief result was to show that the volume of carbonic acid expired from the lungs is almost exactly equal to the volume of oxygen abstracted from the inspired air.

Pepys published the following papers in Tilloch's ‘Philosophical Magazine’: ‘On the Production of Cold,’ iii. 76, 1799.  ‘[On] a Mercurial Gasometer,’ v. 154, 1799.  ‘[On] a Newly Invented Galvanometer,’ x. 38, 1803.  ‘An Improved Chemical Apparatus … 