ABSTRACT
In the eighteenth century with its rapidly expanding international trade, technology that would allow a captain to determine the precise location of his ship at sea was an urgent challenge. Since navigation was imprecise at best, shipwrecks were a calamity that occurred far too often, as ships suddenly ran into rocky shores when they thought they were far from any land. Sailors had been able for many years to fi nd their ship’s latitude-how far north or south they wereby fi nding the angle of the sun at its highest point at local noon. However, determining their longitude —the distance east or westwas still a matter of guesswork. Not knowing the ship’s longitude meant that the ship’s location could be anywhere on a horizontal line stretching around the globe.
