1908.] 



PHYSICAL GEOGRAPHY MACKENZIE RIVER. 



35 



These figures show that the winter climate of the upper and lower 

 Mackenzie varies but slightly, while the summer climate is consid- 

 erably cooler to the northward. 



Summaries of temperature 



taken at Fort Good Hope, Mackenzie, during the 

 mar 1900. 



Summaries of temperatures taken <it Fort McPherson, Mackenzie, during tin 



year WOO. 



January- 

 February 



March 



April 



May 



June 



Mean daily 

 maximum. 



Mean daily 

 minimum. 



Maximum. Minimum 



-22.4 

 -14. S 



."..:; 

 24.2 

 31. S 

 60.2 



-37.6 

 31.2 



1 1.6 

 2.6 



20.4 

 10.8 



16.7 



6.0 

 35.0 

 52 . 5 

 48.9 



S5.0 



Monthly 



mean. 



60.6 



47. t 

 17.2 



22.(1 

 5.0 

 26.8 



-30.0 



-23.0 



- 4.7 



13.4 



26.1 



50.5 



Summaries of temperatures taken at Herschel Island, Mackenzie, during the 



year 1900. 



As has been stated, the warm winds from the Pacific sometimes 

 exert a decided though temporary influence on the climate of the 

 Mackenzie, and the Liard, opening early, disrupts the Mackenzie ice 

 below the confluence. The removal of the icy covering of an immense 



river and the blending with its flood of the waters of a warmer tribu- 

 tary necessarily affect conditions along its banks. The ice in the 

 Liard, having broken its bonds, is forced against that of the Mac- 

 kenzie, through which it opens a passage, and urged on by the 



