Page:Dictionary of National Biography volume 62.djvu/435

 Woolf, a carpenter, by his wife, Jane Newton. He was apprenticed to a carpenter at Pool, near Camborne, and after the expiry of his indentures he went to London, and entered the service of Joseph Bramah [q. v.] at Pimlico as a millwright. In 1795 he became a master-engineer, and in the next year he assisted Jonathan Carter Hornblower [see under ] to repair a fault in a two-cylinder engine which he had erected at Meux's brewery. In consequence he was appointed resident engineer in the brewery, where he remained until October 1806. On 29 July 1803, while residing at Wood Street, Spa Fields, he took out a patent (No. 2726) for ‘an improved apparatus for converting water and other liquids into vapour or steam for working steam engines.’ Two boilers built according to his ideas were erected in 1803 in Meux's brewery. Woolf also proposed to turn his apparatus to heating ‘water or other liquids employed in brewing, distilling, dying, bleaching, tanning,’ and other processes.

Woolf had long considered the possibility of increasing the efficiency of steam engines by driving with steam at a higher pressure than Watt was accustomed to use. Richard Trevithick [q. v.] had already shown the advantages of high-pressure engines, but the danger of explosion prevented him from developing the new departure thoroughly. Woolf ingeniously avoided most of the risks of accident by raising the temperature of the steam in the cylinder itself. In 1804 and 1805 he took out patents embodying his improvements (Nos. 2772, 2863).

In 1806 Woolf became partner with an engineer named Edwards in a steam-engine factory at Lambeth, and while in this position he took out another patent (No. 3346) on 9 June 1810 for further ‘improvements in the construction and working of steam engines.’ His improvements, in fact, consisted of a revival of Hornblower's compound engine, which was rendered possible by the expiry of Watt's patent. Using steam of a fairly high pressure, and cutting off the supply before the end of the stroke in the small cylinder, Woolf expanded the steam to several times its original volume. In engines of this type the steam passed directly from the first to the second cylinder, and in consequence the term ‘Woolf engine’ has since been applied to all compound engines which discharge steam directly from the high to the low pressure cylinder without the use of an intermediate receiver. This type of engine has been more commonly adopted in France than in England.

In 1812 Woolf dissolved his partnership and returned to Cornwall to devote himself to improving methods of mining. In 1813 and 1814 he erected steam stamps for crushing ore at Wheal Fanny mine at Redruth. About 1814 he introduced his compound engine into the mines for the purpose of pumping, erecting engines at Wheal Abraham and Wheal Var in 1814 and 1815. In 1824 he erected engines at Wheal Busy, in 1825 at Wheal Alfred and Wheal Sparnon, and in 1827 at Consolidated mines. His engines were, however, quickly superseded by Trevithick's high-pressure single cylinder engine, which had the advantage of greater simplicity in construction. Until 1833 he acted as superintendent of Harvey & Co.'s engine manufactory at Hayle. He died at The Strand, Guernsey, on 26 Oct. 1837.

[Boase and Courtney's Bibl. Cornub.; Smiles's Lives of the Engineers, iii. 262; Kley's Einfach und direktwirkenden Woolf'schen Wasserhaltungsmaschinen der Grube Altenberg bei Aachen, Stuttgart, 1865; Gregory's Treatise of Mechanics, 1806, ii. 394–404; Stuart's Descriptive History of the Steam Engine, 1824, pp. 168–71; Stuart's Hist. and Descript. Anecdotes of Steam Engines, pp. 470–2, 511; Alban's High-pressure Steam Engine, ed. Pole, 1848, pp. 59–61; Trevithick's Life of Richard Trevithick, 1872; Encyclopædia Britannica, 9th edit. xxii. 477, 494; Mining Almanack, 1849, pp. 170–1; Journal of the Royal Institution of Cornwall, 1872, pp. xlvii–ix; Cornish Telegraph, 15 July 1874; Tilloch's Philosophical Mag. xvii. 40–7, xix. 133–7, xxiii. 123–8, xxvi. 316–17, xlvi. 43–4, 120–2, 295–7, 460–1.] 

WOOLHOUSE, JOHN THOMAS (1650?–1734), oculist, belonged to a family who followed that profession from father to son for four generations. Born, according to Haeser, about 1650, he travelled throughout Europe to make himself familiar with the various methods of treating diseases of the eye, and thus became known to the principal men of the age. He served for a time as groom of the chamber to James II, who also appointed him his oculist. In 1711 he was living at the Hôtel Notre-Dame, Rue St. Benoist, at Paris, where he served as surgeon to the Hospice des Quinze-Vingts. In Paris he is said to have had a large practice, but on his return to England later in his life he failed to secure much attention. He was, however, admitted a fellow of the Royal Society of London in 1721. He was a member of the Royal Academy at Berlin, and of the Noble Institute of Bologna. He died in England on 15 Jan. 1733–4.

Woolhouse appears by his writings to have approached perilously near to charlatanism,