The LONGITUDE design was suggested by the work of John Harrison (1693–1776), the self-taught
Yorkshire craftsman who solved the practical problems of building a timekeeping device accurate
enough to be used to ascertain a ship’s longitude at sea. The graphics of the invitation interior are
based on the delicate penwork on the dial of Harrison’s ‘First Sea Watch’ of 1759, which fulfilled all
the conditions for the £20,000 prize offered by Parliament in 1714 for the first successful means of
finding longitudes, while the other graphics are in the style of engravings of the period.