Mackenzie's Knowledge of the Columbia River.
The Columbia River was discovered by Captain Robert Gray, May ii, 1792, about the time Mackenzie left Montreal on his journey to the Pacific Ocean. The discovery of the Columbia River was not known to Mackenzie, probably, until the return of Vancouver to England in 1795, although Mackenzie may have heard of it after his return, in the fall of 1793, to Montreal, from his expedition, for Captain Gray returned to Boston by the way of the Cape of Good Hope in 1793 or 1794. Mackenzie went to England in 1799 and there supervised the publication of his Journal. It was published in 1801.
Captain George Vancouver returned to London in September, 1795, and his Voyage was published in London in 1798. In this book, Vancouver gave a detailed statement of the discovery of the Columbia River, the latitude and longitude of its mouth, and of the exploration of the Columbia by Lieutenant Broughton from its mouth to Point Vancouver, in October, 1792, a distance of about one hundred miles.
Mackenzie's main Journal of his expedition was published, as written by him, subject to editorial supervision. But in the latter part of this volume is a summary, possibly written by his cousin, Roderick Mackenzie, who is said to have revised the manuscript of Alexander Mackenzie. In this summary the Tacoutche is spoken of as being the Columbia River, and a map is bound in the volume showing between dotted lines the Columbia River as being a continuation of the Tacoutche Tesse, as far south as latitude fifty-one, but no further. Vancouver's Voyage is the undoubted source of Mackenzie's knowledge of the Columbia River, as set forth in the summary to Mackenzie's Journal and in said map.
The course of the Columbia River, for more than the one hundred miles above its mouth, as explored by Lieutenant Broughton, was not known until the Lewis and Clark Expedition in 1 804- 1 806, and then only from the junction of the----