African traveller and missionary, born in Blantyre, Lanarkshire; began life as a mill-worker, studied medicine and theology at Glasgow, and was sent out to Africa by the London Missionary Society in 1840, landed at Port Natal, and addressed himself to missionary work; moving north, he arrived at Lake Ngami in 1849, and ascending the Zambesi in 1853 arrived at Loanda next year; later on he explored the course of the Zambesi and its tributaries, discovered Lake Nyassa, and set himself to discover the sources of the Nile, but this expedition proved too much for him, and he died exhausted; his body was embalmed, brought home to England, and buried in Westminster Abbey (1815-1873).