Forthwith the North-west Company bought up the derelict property of Mr.Astor's Company from his not very honest British employees, and the few Americans in the concern retreated inland, and, after almost incredible sufferings from the attacks of unfriendly Indians, succeeded in reaching the Mississippi.
[Illustration: THE KOOTENAY OR HEAD STREAM OF THE COLUMBIA RIVER] This Columbia River had in reality been discovered at its sources, and traced down to the sea, between 1807 and 1811 by DAVID THOMPSON (once a Blue-coat boy in London; from 1784 to 1792 in the service of the Hudson's Bay Company, and after that one of the most famous of the Nor'-westers).

The upper course of this river and its northern affluents were annexed as British by David Thompson; the lower course did not at once become the political property of the United States, but was considered vaguely to be the joint property of both nations, till the Oregon settlement of 1846.

By the treaty of 1792, the southern boundary of central Canada was agreed upon as being the 49th degree of north latitude, but only between the Lake of the Woods and the Rocky Mountains.

The agreement of 1846 continued the 49th degree boundary to the shore of the Pacific opposite Vancouver Island.
Prominent among the agents of the North-western Company who followed Sir Alexander Mackenzie as a pioneer towards the Pacific shores was ALEXANDER HENRY THE YOUNGER,[1] regarding whose journeys some extracts may be given.
[Footnote 1: The nephew of the Alexander Henry already mentioned as an explorer between 1761 and 1775.] The first entry in his diary of 1799 is not particularly romantic, but shows some of the unexpected dangers attending the life of an adventurer in the far north-west.

He had been riding through the Assiniboin country in the autumn of 1799, probably after one of the very indigestible meals which he describes here and there in his pages.