Mr. Ogilvie claims that there is a grand total of three thousand three hundred and sixty-nine miles of water in Mackenzie basin, all navigable, except for eighteen miles, at but two points, one a rapid two miles long on Peace river, and the other Sixteen Mile rapid on Great Slave river. A thorough knowledge of the two great lakes (Great Bear and Great Slave) with all their tributary streams would probably increase this vast length of navigable water by several hundred miles. This does not take into account the Mackenzie delta and sea near its mouth, of the navigability of which nothing very definite is known at present. Mr. Ogilvie, writing in 1890, figured out these distances in this way:—“The Hudson’s Bay Company’s steamer ‘Grahame’ traverses the waters of Peace and Athabaska rivers, the former from the falls to the rapid at Fort Smith, and the latter up to McMurray. The distance from Chipewyan to the post at the falls on Peace river is two hundred and twenty-two miles.” “During the last two years the Hudson’s Bay Company has had another steamer, the ‘Athabaska,’ plying on upper Athabaska river, between Little Slave river and Grand rapids. Both this steamer and the ‘Grahame’ on the lower river are flat bottomed stern-wheelers, drawing, when loaded, not more than two and a half to three feet of water. They can each carry about one hundred and forty tons.” “Upper Peace river is navigable for steamers drawing three or four feet of water, and, with a little improvement at two points, a draught of five to six feet could be utilized. This upper Peace river affords a navigable stretch of five hundred and fifty-seven miles, which, with two hundred and twenty-two miles on lower Peace river, and two hundred on Lake Athabaska, and, say, two hundred on the lower Athabaska, together with the distance given in the above table, gives us two thousand five hundred and sixty-nine miles of navigable water.” “From our present knowledge, meagre as it is, I think we may assume that Great Slave lake affords us at least five hundred miles more, considering its length and its many deep bays. To this we may add two hundred and forty miles on the Liard, and at least sixty on Peel river.” THE SEASON OF NAVIGATION. As to the length of the season of navigation on the Mackenzie, Mr. Wm. Ogilvie, in his report, publishes some tables showing dates at which the ice formed and broke up at Fort Norman (latitude about 65°), and Fort Simpson (latitude 61° 52′ north). These tables were compiled from figures taken from the journals kept at all Hudson’s Bay Company’s posts. From these figures it appears that the first ice, between 1872 and 1888, never formed earlier than October 7 at Fort Norman, and in 1883 did not form until October 24. The earliest date at which the river was closed by the ice was November 2, in 1879, and the latest November 18, in 1874. The earliest date at which the ice broke up was May 9, in 1879, and the latest May 24, in 1887.