Memoir, descriptive and explantory, to accompany the general chart of the Northern Ocean, Davi's strait, and Baffin's bay including the navigation for Great-Britain and Ireland to Spitzbergen and the White sea : and containing 1. Tables of the determinded positions and of all the principal points... 2. The general phaenomena of the Northern ocean... 3. Particular descriptions of the coasts and islands ; with directions for sailing... / John Purdy