This paper was first published in Astronomy and Geophysics (December 1998, Vol. 39) by the Royal Astronomical Society and the Institute of Physics Publishing Ltd and is reproduced here, with minor amendments, by kind permission of the Editor, Dr Sue Bowler.

William Wales (1734–1798) contributed to astronomy through his observations of the 1769 transit of Venus, and his studies of latitude and longitude on Captain James Cook's second voyage to the South Seas. During this voyage, Wales was responsible for monitoring the performance of the chronometers. After returning from the Pacific, Wales took charge of the Royal Mathematical School at Christ's Hospital in London and, over the next two decades, he taught a succession of budding officers the principles of navigation.