358 ASSINNIBOINE AND SASKATCHEWAN EXPEDITION. 



much heat from the warm westerly winds coming from 

 the Pacific Ocean, as to neutralize their influence upon 

 the winter and spring temperature of a large part of the 

 country drained by the Saskatchewan. Such, however, 

 is not the case ; and happily for the purpose of practically 

 substantiating this apparent anomaly, we have indisput- 

 able testimony. 



In the magnetical and meteorological observations at 

 Lake Athabasca and Fort Simpson, by Colonel Lefroy, 

 E. A., we find the following important observation, in 

 relation to the phenomena of Pacific winds affecting the 

 climate of the northern regions : — 



" A local phenomenon of interest was observed several 

 times at Fort Simpson (lat. 61° 51' 7" K, long. 15° 

 5' 40" W.), 460 miles from Sitka (1800 geo. miles from 

 Toronto), in the rapid rise of the temperature of the air, 

 when the wind changed to the south-west from an easterly 

 direction. It appeared as if the warmer air of the Pa- 

 cific Ocean were transferred across the neighbouring 

 ridges of the Eocky Mountains with little loss of its tem- 

 perature." 



Much of the precipitation in the humid region is due 

 to the Pacific winds, which are not so completely de- 

 prived of their moisture in traversing the Eocky Moun- 

 tain Eanges as in lower latitudes, where the average 

 altitude of these ranges is much higher, and the eastern 

 slope of the mountain of a far greater mean annual tem- 

 perature. 



The prevalent winds at Toronto and Lake Athabasca 

 belong, as shown by Colonel Lefroy *, to different and 

 nearly opposite systems. A north-westerly current pre- 

 ponderates in the lower latitudes (43° 39'), a north-easterly 

 current, inclined at an angle of about 117° prevails 



* Magnetical and Meteorological Observations at Lake Athabasca. 



