OF THE POLAR SEA. 159 



and report it to be navigable for Indian 

 canoes only. The forms of the south and 

 western shores are better known from the 

 survey of Sir Alexander Mackenzie, and in 

 consequence of the canoes having to pass 

 and repass along these borders annually 

 between Moose-Deer Island and Mac- 

 kenzie's River. Our observations made 

 the breadth of the lake, between Stony 

 Island and the north main shore, sixty miles 

 less than it is laid down in Arrowsmith's 

 map ; and there is also a considerable dif- 

 ference in the longitude of the eastern side 

 of the bay, which we entered. 



This lake, owing to its great depth, is 

 seldom completely frozen over before the 

 last week in November, and the ice, which 

 is generally seven feet thick, breaks up 

 about the middle_of June, three weeks later 

 than that 'of the Slave River. The only 

 known outlet to this vast body of water, 

 which receives so many streams on its 

 north and south shores, is the Mackenzie's 

 River. 



August 3, — We embarked at three A.M. 



