PHILIPPE BUACHE/ENGLEBERT KAEMPFER

A very interesting pair of rare maps published as a single sheet in the 10 part series of maps created by Robert de Vaugondy in his supplement Receuil de 10 cartes traitant particulierement de l’Amérique du Nord to Denis Diderot’s Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers examining the existence of a Northwest Passage.  It has been argued that the supplement “was one of the first studies of comparative cartography.”
The two part map is actually derived from Philippe Buache’s important and controversial work Considérations Géographiques sur les Nouvelles Decouvertes au Nord de la Grande Mer in 1754. It was the Considérations Géographiques, presented to the Académie Royale des Sciences in Paris between 1752-54, that helped ignite one of the greatest debates in cartography in the 18th Century. t is important to note, that what gave credence to the body of maps found in the Considérations Géographiques is the  implied association with Joseph-Nicolas de l’Isle, Buache's  brother in law, who had recently returned from the Royal Academy in St-Petersburg and who’s brother was none other than Guillaume de l’Isle, one of the most important and influential cartographers of the 18th Century.  
As such, the controversy that ensued following the publication of the Considérations Géographiques revolves around the depiction of the Mer de l’Ouest in the Pacific Northwest of North America.
Although Guillaume de l’Isle, did produce a manuscript map in 1696 that toyed with the concept of an inland sea, which was later spuriously copied by Jean-Baptiste Nolin in 1700, the controversial depiction, and the implications that it entailed, of a possible inland route to the Pacific, remained somewhat dormant for the next 50 years.  
The bottom depiction is derived from a map given to the president of the the Royal Society in London, Hans Sloane, by Englebert Kaempfer who was a German national who worked for the Dutch East India Company in the Japanese “open” port of Nagasaki.  To the right and left of the map are two sets of notations.  The notations basically claim that Kaempfer derived his information from a Japanese manuscript map that was to be found at the Palace of the Japanese Emperor.  As such, the notation claims that the depiction is a good example of the state of cartographic knowledge of the North Pacific region by the Japanese and Chinese.
The current map is thus of interest not only for its intriguing and speculative depictions as it relates to the Northwest passage and of the  possibility of an inland route to the Pacific, but also because of its association with the body of maps found in the controversial Considerations Geographiques.  The two part map is also a beautiful example how an idea of an inland sea sparked a generation of exploration in the Pacific Northwest which culminated in James Cook’s famous third Voyage to put the controversy to rest. It is also a rare glimpse in how the region was viewed by Asian cartographers, albeit from a second hand source.