Within the next few years discoveries followed thick and fast. The North West Company, the Canadian rival of the Hudson's Bay Company in the western fur trade, was reaching out eagerly for new fields to conquer, and the more adventurous of its officers, scouting far ahead of the main army, became more explorers than fur-traders. Mackenzie was himself a partner of the North West Company, and where he led others soon followed, breaking new trails through the mountains, leaving the level plains and comparatively sparse vegetation of the eastern side, and coming down into the almost tropical luxuriance of the Pacific slope. David Thompson, the astronomer of the North West Company, was the first to find a way through the mountains in the neighbourhood of the Kicking Horse Pass route, or the main line of the Canadian Pacific Railway. In 1800 he made his way over to the Columbia Valley, perhaps by what was later known as the Simpson Pass; and the same year Duncan McGillivray found a route farther north by Howse Pass, named after Jasper Howse, another Rocky Mountain explorer. Simon Fraser, who had followed Mackenzie through the Peace Pass, in 1808 explored the river that bears his name from the mountains to the sea, descending its terrific canyons in a frail canoe. At the very time that Fraser was making his way down this river, Thompson was exploring the Kootenay and the Columbia. Two years afterward the latter discovered the Athabaska Pass, which for many years was to remain the principal highway of the fur-traders back and forth through the mountains. Often enough the mountains above the pass must have looked down upon the picturesque cavalcade of traders, carrying goods over to the posts in New Caledonia or down the Columbia, or bringing back the "returns" as the cargoes of furs were called. One can picture the long string of pack-horses climbing up the pass, with the cheerful philosophy (or diabolical cunning) of the Indian cayuse, urged forward by fluent traders. One can see, too, at nightfall, the camp-fires in the mountains; horses, browsing contentedly; men lounging about waiting for their supper, perhaps fresh venison, or the old stand-by pemmican; and later, pipe and story and song--the beautiful old _chansons_ of French Canada with their haunting refrains: A la claire fontaine M'en allant promener, J'ai trouvé l'eau si belle Que je m'y suis baigné. _I' ya longtemps que je t'aime, Jamais je ne t'oublierai._ or-- Derrier' chez nous, ya-t-un étang, _En roulant ma boule_. Trois beaux canards s'en vont baignant, _En roulant ma boule. Rouli, roulant, ma boule roulant, En roulant ma boule roulant, En roulant ma boule._