THOMSON, JOSEPH (1858-1895), Scottish explorer in Africa, was born on Feb. 14, 1858 at Penpont, Dumfriesshire, being the fifth son of William Thomson, originally a working stonemason, who had attained the position of a master builder. In 1868 his father removed to Gatelawbridge, where he rented a farm and a quarry. Joseph Thomson worked in his father's quarry before he went up to Edinburgh University. After com pleting his course in 1878 he was appointed geologist and natural ist to the Royal Geographical Society's expedition to East Cen tral Africa under Keith Johnston. The latter died at Behobeho, between the coast and the north end of Lake Nyasa, in June 1879, and Thomson then took command. He successfully con ducted the expedition across the desolate region of Uhehe and Ubena to the north end of Lake Nyasa, and then by a hitherto unexplored track to Lake Tanganyika, where he investigated the Lukuga outlet. From Tanganyika he started to reach the Congo, but troubles with his carriers, who dreaded the warlike Warua, obliged him to retrace his steps. Going round the south end of Tanganyika he discovered Lake Rukwa, and marched via Tabora to the coast at Bagamoyo, reaching London in August 1880.
About this time the sultan of Zanzibar asked Thomson to report on certain supposed coal-beds on the river Rovuma, but the coal proved to be merely bituminous shale.
For a considerable time the explorer had directed his attention to Masailand, through which ran the shortest route from the sea to the headwaters of the Nile. In 1882 the Royal Geographical Society requested Thomson to report on the practicability of 'Bysshe Vanolis: "Bysshe," as the commonly used Christian name of Shelley, Thomson's favourite writer ; and "Vanolis," an anagram of Novalis (F. von Hardenberg).
taking a caravan through the Masai country. He succeeded in crossing the Njiri desert and exploring the eastern rift-valley. Thence he went with a picked company through Laikipia to Mt. Kenya and Lake Baringo, afterwards traversing the unknown region lying between Baringo and Victoria Nyanza, reached on Dec. 1o, 1883.
In 1885 he undertook an expedition to Sokoto for the National African (afterwards the Royal Niger) Company, and obtained the signatures of the sultans of Sokoto and Gando to treaties with which he had been entrusted by the company. In 1888 he
travelled for pleasure through southern Morocco and explored a portion of the Atlas range.
In 1890 he entered the service of the British South Africa Company and starting from Quilimane he traversed the region between lakes Nyasa and Bangweulu and the Zambezi. It was a period of tension between the Portuguese and the and Thomson's party on leaving the Portuguese frontier was fired on by the Portuguese who, too late, realized that they had allowed a treaty-making envoy to pass through their territory in the guise of a peaceful trader. Thomson concluded treaties with native potentates which gave to the chartered company political, trad ing and mining rights over a large part of the district since known as North-East Rhodesia. This journey, in which he covered nearly a thousand miles of hitherto unexplored country, proved disastrous to his constitution. In 1893 he visited South Africa in search of health, but unavailingly. He died in London on Aug. 2, 1895. The accounts of his travels not recorded in the books mentioned were published in magazines or in the Proceedings of the Royal Geographical Society. Thomson was the last, as he was one of the most successful, of the great geographical pioneers in Africa. He had an extraordinarily keen topographical instinct which enabled him to comprehend at a glance the natural features of the countries he traversed. To undaunted courage and prompt ness of decision he added a forbearing and patient disposition.
Thomson wrote accounts of his travels under the titles To the Central African Lakes and Back (1880 Through Masailand (1884) ; Travels in the Atlas and Southern Morocco (1889) ; also some articles in the Proceedings of the Royal Geographical Society. He also wrote, in collaboration with Miss E. Harris Smith, Ulu (i888), a novel based on his insight into the working of the African mind, Mungo Park and the Niger (189o), a sound critical biography and many magazine articles on African politics.
See Joseph Thomson, African Explorer (1896), a biography by his brother, the Rev. J. B. Thomson, which contains a list of the published writings of the explorer.