As a result of the new undertakings set on foot by the North-westers and the reawakened Hudson's Bay Company, both companies entered the Columbia Valley. The struggle for possession of Oregon between the English and American fur companies and their government was on. In the summer of 1810 David Thompson of the North-west company crossed the continental divide by the Athabasca Pass in latitude 52 deg. 25'. The North-westers had heard of the Astor enterprise in New York and realised that they must be up and doing if they would control the land of the Oregon. Although the character of soil, climate, and productions of the Columbia Valley was but imperfectly known, enough had been derived from Lewis and Clark, and from ocean discoveries to make it plain that the Columbia furnished the most convenient access to the interior from the sea, and that its numerous tributaries furnished a network of boatable waters unequalled on the Western slope, while there was every reason to suppose that its forests abounded in fur-bearing animals and that its climate would admit of much longer seasons of work than was possible in the biting winters of the Athabasca. It became vital to the continental magnitude of the designs of the Canadian companies that they control Oregon. For greater topical clearness we will anticipate a little at this point and state that after several years of intense rivalry it became plain to the British Parliament that it was suicidal to allow a policy of division in the face of a common enemy. Hence in 1821, by act of Parliament, the two companies were reorganised and united under a charter which was to last twenty-one years (and as a matter of fact was renewed at the end of that time), and under the provisions of which the North-westers were to have equal shares in both stock and offices, though the name of the Hudson's Bay Company, was retained. It will be remembered therefore, that up to the year 1821, the two great Canadian companies were distinct, and that during that time the North-west Company was much the more active and aggressive in the Columbia Valley, but that after that date the entire force of the Canadian Companies was combined under the name of the old monopoly. But however bitter the first enmity of the Canadian rivals, they agreed on the general proposition that the Americans must be checkmated, and during the score of years prior to their coalition they were seizing the pivotal points of the Oregon country. During the next two decades they created a vast network of forts and stations, and reduced the country contiguous to the River and its tributaries to a system so elaborate and interesting as to be worthy of extended study. We can sketch only its more general features. And the more perfectly to understand them, we must arrest here the story of the great Canadian monopoly and bring up the movement of the American fur companies.