Navigating the Pacific from Bougainville to Dumont d’Urville: French Approaches to Determining Longitude, 1766–1840

Abstract

Defeated in the Atlantic during the Seven Years’ War, the French turned to the Pacific with the hope of finding new lands and markets that would redress the balance of power so grievously disturbed by the expansionist energies of perfidious Albion. France, however, faced the same problem as its rival in venturing into what was, from a European perspective, largely a new quarter of the globe. Navigating the Pacific magnified across a third of the Earth’s surface the problem of locating one’s position with exactitude; in particular, it required determining longitude at sea. The means to do so had been an increasing preoccupation of both the British and French states and their associated scientific establishments. As Danielle Fauque and Guy Boistel show in this volume, various French techniques for solving this problem had been recorded before the deployment of John Harrison’s epochal invention, his sea watch ‘H4’, in 1761. The conclusion of the Seven Years’ War in 1763 was, however, to lead to a fruitful interaction between both nations’ attempts to solve ‘the longitude problem’.