John Harrison
Ascension, 1971
John Harrison (1693–1776) was an English instrument-maker who invented the marine chronometer for
finding longitude at sea. Seeking to win a £20,000 prize offered by the British government, Harrison developed a series of
chronometers between 1735 and 1761. The stamp above, one of a classic set from
Ascension Island on the history of astronomy and space travel, shows the first
Harrison chronometer, completed in 1735, but the ship depicted is named as the
frigate HMS Deptford, on which the fourth and most successful chronometer was tested on a voyage to
the West Indies and back in 1961–62.
Harrison’s achievements are recognized on several British stamps, such as the Marine Timekeepers set from 1993.
Stanley Gibbons no. 140
