abstract
The Tristan da Cunha Island group consists of four islands, three of which, Tristan, Inaccessible and Nightingale, lie close together in the central South Atlantic near 37癝, 12癢. The fourth island, Gough, lies approximately 350 km SSE of the other three at 40癝, 10癢. The nearest continental land mass, Southern Africa, is about 2800 km to the east and the nearest point in South America lies some 3200 km westwards.