Paul Harrison Avery

THE IMPACT OF THE EIGHTEENTH-CENTURY NAVIGATION REVOLUTION UPON EUROPEAN PACIFIC CARTOGRAPHY.

(Under the direction of Bradley A. Rodgers) Department of History, April 1998

Britannia hastened Pacific exploration, during the eighteenth century setting standards by which every expedition was measured. Captain James Cook and his compatriots did not singularly chart the Pacific, however. Portuguese, Spanish, Russian, and French sailors, likewise, there ventured, charted, learned, lived, and died. In this pursuit, European exploration of the Pacific pushed understanding of sailing, navigation and even nutrition beyond safe limits, for once in the Pacific, away from South America's coast, prior to the 1760s, a navigator was lost. Using his best dead‑reckoning, a pilot calculated his ship's position, but without precise longitude he was almost certain to be wrong. Consequently, pilots created charts of only limited use. Furthermore, the duration of a Pacific voyage induced terrible suffering among sailors who remained aboard a crowded, unhealthy vessel for months, living among filth, rats, roaches, and deadly microbes. As if these maladies were not enough, scurvy likewise relentlessly tormented and killed as it decimated a stricken crew. Amidst such horror sailors survived to recount tales of strange people and distant lands, and in so doing they inspired the next generation's adventurers.

Pacific exploration reached a crescendo during the last half of the 1700s, as the Age of Enlightenment prompted governments to make massive expenditures upon voyages of discovery. Throughout this era, individuals collectively brought the vast, unknown Pacific into the Age of Reason, in which scientists measured, charted, and laid bare its hidden recesses. These voyages supplied cartographers with volumes of detailed geographic information, which by the second half of the eighteenth century allowed map‑makers to construct precise maps and navigational charts of the entire Pacific. The key to precision mapping is knowing both latitude and longitude and the principle means by which explorers ascertained the latter will be the focus of this thesis. Dead‑reckoned, chronometer, and lunar distance derived longitude all played significant roles mapping the Pacific, but it was the navigator utilizing lunar distance and chronometer longitude who recorded results most advantageously. Both lunar distance and chronometer derived longitude enabled accurate location determination, although as this thesis will demonstrate, the navigator relying upon chronometers alone produced inconsistent results, while the navigator utilizing lunar distance longitude typically recorded accurate coordinates.