The great probability of a North West Passage / deduced from observations on the letter of Admiral de Fonte

THE
GREAT PROBABILITY
OF A
NORTH WEST PASSAGE.
A General Map OF the DISCOVERIES of Admiral de Fonte, Exhibiting the great Probability of a North-west Passage BY Thomas Jefferys, Geographer to the KING.
DEDUCED FROM OBSERVATIONS ON THE Letter of Admiral DE FONTE, Who sailed from the Callao of Lima on the Discovery of a Communication BETWEEN THE SOUTH SEA and the ATLANTIC OCEAN; And to intercept some Navigators from Boston in New England , whom he met with, Then in Search of a NORTH WEST PASSAGE.
PROVING THE AUTHENTICITY of the Admiral's LETTER. With Three Explanatory MAPS.
1st. A Copy of an authentic Spanish Map of America , published in 1608. 2d. The Discoveries made in Hudson 's Bay, by Capt. Smith , in 1746 and 1747. 3d. A General Map of the Discoveries of Admiral de Fonte .
By THOMAS JEFFERYS, Geographer to the King.
WITH AN APPENDIX. Containing the Account of a Discovery of Part of the Coast and Inland Country of LABRADOR, made in 1753.
The Whole intended for The Advancement of TRADE and COMMERCE.
LONDON: Printed for THOMAS JEFFERYS, at Charing Cross. MDCCLXVIII.