There is an excellent portrait by Geddes. It was presented to Thomson in 1822 by the medical officers of the army and navy who had attended his lectures, and it has been well engraved in mezzotint by Hodgetts. A characteristic marble bust copied from that executed by Angus Fletcher about 1820 is in the hall of the library of the university of Edinburgh.
Thomson wrote in addition to many pamphlets of ephemeral interest:
- ‘The Elements of Chemistry and Natural History, to which is prefixed the Philosophy of Chemistry by M. Fourcroy,’ translated with notes, vol. i. Edinburgh, 1798, vol. ii. 1799, vol. iii. 1800; the work reached a fifth edition.
- ‘Observations on Lithotomy, with a new Manner of Cutting for Stone,’ 8vo, Edinburgh, 1808. An appendix was issued in 1810. The original work and the appendix were translated into French, Paris, 1818.
- ‘Lectures on Inflammation: a View of the general Doctrines of Medical Surgery,’ Edinburgh, 8vo, 1813; issued in America, Philadelphia, 1817, and again in 1831; translated into German, Halle, 1820, and into French, Paris, 1827. This important series of lectures was founded upon the Hunterian theory of inflammation, and moulded the opinion of the profession for many years, but of late the study of experimental pathology has profoundly modified our views of inflammatory processes.
Thomson also edited ‘The Works of William Cullen, M.D.,’ Edinburgh, 1827, 8vo, 2 vols., and wrote an account of his life, of which volume i. was published in 1832, and was reissued, with a second volume and biographical notices of John and William Thomson, in 1859.
[Biographical notice by William Thomson and David Craigie, in the Edinburgh Medical and Surgical Journal, 1847, No. 170, prefixed with slight alterations to the reissue of Cullen's Works, Edinburgh and London, 1859; Journal of Henry Cockburn, a continuation of the Memorials of his Time, 1831–4 ii. 164; Gordon Laing's Life of Sir James Young Simpson, 1897, p. 73.]
THOMSON, JOSEPH (1858–1894), African explorer, fifth son of William Thomson, by his wife Agnes Brown, was born on 14 Feb. 1858 in the village of Penpont, Dumfriesshire, in a house which his father—at first a journeyman stonemason—had built for himself and his family. In 1868 the household removed to Gatelawbridge, where William Thomson became tenant of a farm and a freestone quarry. Under the stimulus of his father's example and the quaint enthusiasm of a neighbour, Dr. Thomas Boyle Grierson, Thomson as a lad developed a keen interest in geology as well as in other branches of natural science. To Dr. Grierson's local ‘Society of Inquiry’ he contributed papers on the ‘Peroxide of Iron in the Sandstone of Gatelawbridge Quarry,’ ‘Some Peculiar Markings in the Sandstone of Gatelawbridge Quarry,’ and ‘The Stratification of the Sandstone of Gatelawbridge Quarry, with special reference to the Unconformable Character of certain Strata.’ From 1871 onwards the geological survey was at work in Nithsdale, and by a happy chance the young geologist fell under the notice of Professor Archibald Geikie at Crichope Linn, and had the delight of learning that his own eye had discovered in his native rocks three ‘fossil ferns’ till then unknown there. Leaving school in 1873, Thomson worked for a short time in his father's quarry, but by the winter of 1875 he had made up his mind to study his favourite sciences in the university of Edinburgh. In his first session, besides studying geology under Professor James Geikie and botany under Professor John Hutton Balfour [q. v.], he had the opportunity of attending a course of lectures on natural history by Professor Huxley. In 1877 he came out as medallist both in geology and in natural history.
In 1878 Thomson was appointed geologist and naturalist to an expedition under Alexander Keith Johnston (1844–1879) [q. v.], which was sent out by the Royal Geographical Society for the exploration of East Central Africa. The expedition reached Zanzibar on 5 Jan. 1879. On 19 May a start for the interior was made. By the death of Keith Johnston on 28 June 1879 within the malarial zone at Behobeho, Thomson suddenly found himself leader of the expedition. He reached Lake Tanganyika on 3 Nov., and on Christmas day had the pleasure of confirming Stanley's theory as to the geographical relations of the Lukuga outlet of the lake. After a brief visit to Ujiji on the eastern shore, Thomson again started westwards with the intention of reaching the headwaters of the Congo; but a mutiny of his men—alarmed at the risks they ran from the warlike Warua—obliged him to turn back (1 March 1880) when within a day's march of the river. His homeward route from the south end of the lake northward towards Tabora gave him an opportunity of making a detour to the neighbourhood of Lake Leopold (Lake Hikwa), which he was the first white man to see. By 27 May 1880 Thomson was resting at Tabora (Unyanyembe), and after a march of five hundred miles he reached the coast on 10 July. He recorded his experiences in ‘To the African Lakes and Back’ (2 vols. 1881).
