A voyage of discovery to the North Pacific Ocean, and round the world : in which the coast of north-west America has been carefully examined and accurately surveyed : undertaken by His Majesty's command, principally with a view to ascertain the existence of any navigable communication between the North Pacific and North Atlantic Oceans, and performed in the years 1790, 1791, 1792, 1793, 1794 and 1795, in the Discovery sloop of war, and armed tender Chatham, under the command of Captain George Vancouver