This is a single sheet with two very rare and important maps depicting the apocryphal 'Mer de l'Ouest' and the Strait of Anian by Joseph-Nicholas de L'Isle, which were at the center of one of history's most heated cartographic debates about the existence of the Northwest Passage.
Both of these fascinating maps were prepared by the prominent, yet controversial cartographer Joseph-Nicholas Delisle, and published as part of his rare pamphlet, Nouvelles cartes des decouvertes de l'Amiral de Fonte, et autres navigateurs espagnols, portugais, anglois, hollandois, françois et russes, dans les mers septentrionales (Paris, 1753).
The first map, Carte dressée par M. Guillaume De L'Isle... depicts the late Guillaume De L'Isle's conception of the Mer de l'Ouest, the great apocryphal sea that occupied much of western North America, and which was thought provide a link to the Northwest Passage. It takes the form of a massive round sea, which opens to the Pacific around the place of modern day Oregon, and is ambiguously left open in its northern reaches, supposedly to connect to the Northwest Passage. The mythical kingdom of Quivira is located on the sea's southeastern shore, near the terminus of the mythical Riviere de l'Ouest, which held out the hope of a relatively easy voyage from the Mississippi to the Pacific. In sharp contrast, the rest of the content is shown in a very accurate form, as California is properly connected to the mainland, and the Rio Grande, the Mississippi River and the Great Lakes are properly delineated.
The second map, Carte dressée sur la lettre de l'Amiral de Fonte, was devised by Joseph-Nicolas De L'Isle to depict the Northwest Passage as claimed to have been discovered the Admiral Bartholomew Fonte, an apocryphal Spanish naval officer. A letter supposedly by Fonte, dated 1640 was first published in London in the Memoirs of the Curious (1706). In this letter, Fonte claimed that he was ordered by his king to sail from Callao, Peru northwards up the coast. Upon his journey, he claimed that he encountered a ship from Boston that had traversed the Northwest Passage, sailing through the 'Detroit d'Anian', as shown on the map. While Fonte's letter is now universally considered to have been a hoax, the story it told proved to be highly influential throughout much of the 18th-century.
Joseph-Nicolas Delisle (1688-1768) was French geographer and the younger brother of Guillaume Delisle (1675-1726), mapmaker to the King of France. Joseph-Nicolas Delisle served as the head of the Russian Imperial Academy of Sciences in St. Petersburg from 1726-47, at which time he had access to the information then being transmitted to St. Petersburg by the Russian explorers in the North Pacific. From 1733 onwards a series of Russian expedtions under the leadership of Vitus Bering reached Alaska, making the first step towards the mapping of the Pacific Northwest of North America. Upon his return to Paris from St. Petersburg in 1747, Joseph-Nicolas Delisle began disseminating much of what he learned while in the service of the Russian Academy, a disclosure which greatly angered his former Russian employers.
Guillame Delisle continually experimented with new theories and discoveries in the sketches he made in preparation for his printed maps. Shortly before 1700, he drew a manuscript map depicting the supposed Mer de l'Ouest. Critically, Delisle never included this information on any of his published maps. Following Guillaume's death in 1726, Joseph-Nicolas found the manuscript map in his brother's papers, and evidently decided to keep it out of the public eye for some years.
Upon his return to France, one of Joseph-Nicolas Delisle's obsessions, which he shared with his nephew (by marriage), the cartographer Philippe Buache, was mapping the apocryphal Mer de l'Ouest and the alternative theory of the Strait of Anian.
Joseph Nicolas Delisle and Buache first worked together on a manuscript map that was presented to the Academy Royale in 1750, and was in good part based on Guillaume Delisle's manuscript. This formed the basis of a map that was subsequently published by Buache, the Carte Des Nouvelles Decouvertes Au Nord de la Mer de Sud (Paris, 1752), although it featured some notable amendments.
Joseph Nicolas Delisle was displeased by how Buache altered the details featured in their joint manuscript for the printed version, and this led to a falling out between the two cartographers. In response, the following year, Joseph Nicolas wrote the Nouvelles cartes des decouvertes . . . as a reprise, in good part, to properly represent his late brother's work.
The present examples of the maps are presented together on a single sheet. De L'Isle's Nouvelles cartes des decouvertes contains 4 maps which are placed at the end of the pamphlet after the 60 pages of text. The present maps represent the second and fourth maps (as they would appear if bound in the pamphlet), and were not intended to remain together on this one sheet, although there are surviving examples of the text in which the 2 maps appear on a single sheet.
The present maps are historically important, as they helped to reignite a great intellectual debate about the nature of the North Pacific, and whether the Northwest Passage truly existed. The matter was of great consequence, as the discovery of Northwest Passage would revolutionize international commerce and navigation. England, France, Spain and Russia dedicated vast resources to solving the mystery, and Europe's greatest intellectuals pondered the question. Many of leading mapmakers, such as Robert de Vaugondy and Thomas Jefferys sought to portray the Mer de l'Ouest and its supposed connection to a transcontinental passage. Denis Diderot focused heavily on the debate in his monumental L'Encyclopedie (1751-1772), the single most influential publication of the Enlightenment era.
The Third Voyage of Captain James Cook (1776-1780) and the subsequent expeditions of George Vancouver and various Spanish navigators definitely disproved the existence of the Mer de l'Ouest, the Strait of Anian, or any other passage running through the interior of the North American continent.
Rarity
The present maps and the pamphlet in which they appeared are very rare. We are not aware of any of the maps from the Nouvelles cartes des decouvertes appearing separately on the market during the last 25 years and the pamphlet has appeared only once in a dealer's catalog and once at auction during the same period.
We offered an example of the pamphlet, bound with two other works, in 2023.