A rare world map concerning the famous voyages and discoveries made by James Cook.  The map was made by Lt. Henry Roberts who sailed as Masters Mate  with Cook on board the HMS Resolution in  his Third Voyage to the Pacific in 1776-79.
It is important to note that Roberts published two world maps in 1784 that were virtually identical.  The current map, which was separately issued by William Faden, and another which is considered the “official” map that was included in the authorized account of the Third Voyage published in the Atlas that accompanied A Voyage to the Pacific Ocean, in 1784.  The main difference between the two states relates to the annotations found at the bottom of the respective maps, and more importantly, the greater detail found on the map published by Faden.  For example, whereas Roberts’ in the “official” map depicts the Third Voyage as reaching as far South as Cape Mendocino, his “unofficial” map limits the extant of the voyage but adds places near the Californian coast that include Cape St-Lucar, New Years Harb or Monterey, and, most significantly, the Entrance of Juan de Fuca below Nootka Sound.  It has been argued that these places might have been added to underscore the British discoveries in the Pacific “perhaps foreshadowing the anticipated intrigue between Russia and European nations over California and the Northwest Coast.”  As for the omission of the Entrance of Juan de Fuca in Roberts’ “official” map, it could be argued that it would be in Britain’s interest to limit further exploration by competing European powers to find an entrance for the coveted Northwest Passage.
It is of further interest to underline that Roberts also published a map in 1784 that focused solely on the Pacific North East of Asia and North West of America that the editors of A Voyage to the Pacific Ocean refused to publish. This map, entitled Chart of the N.W. Coast of America and the N.E. Coast of Asia Explored in the Years 1778 and 1779. Prepared by Lieut. Heny. Roberts under the immediate Inspection of Capt Cook . . . 1784 which today is better known as “The Legendary Lost Chart of Captain James Cook”, was also published by Faden along with Roberts’ A General Chart… Both of these maps, including the “official” world map that was included in A Voyage to the Pacific Ocean, incorporated the discoveries of Samuel Hearne near the Coppermine River in Northern Canada. As such, Roberts’ “Lost Chart” along with his two published world maps, are the first to publish, what had until then, only been drawn in manuscript form by Hearne, of the impossibility of a Northwest passage through Hudson’s Bay.  Furthermore, Roberts’ chart depicts, in much greater detail, the interior of the North where traders for the Hudson’s Bay Company  plied their trade.The question as to why only Roberts’ “Lost Chart” may have been dismissed from the official account as opposed the the world map is somewhat puzzling.
Roberts’ world map, which focus’ the viewer’s attention towards the Pacific Northwest by placing the Americas in the Eastern quadrant, as opposed to the more conventional world depictions, foretells of a geo-political world who’s centre of attention was shifting to the Pacific Northwest.As such, this rare map is a testament not only to the exploits of Cook’s famous discoveries, but also underlines the political dimensions that they entailed.
(Sources: Wagner, Northwest Coast #700, #696, BLR #38890, Campbell, A Cook Mystery Solved, Sep. 85)