CLIMATE AND CAUSES 201 



"We see that the summer temperature in the North West 

 Territories is exceptional. Believing, however, that, in addition 

 to the quoted causes, there are others which contribute to this 

 result of exceptional temperature, I propose for the present to 

 reserve the fact for further comment, and pass on to the subject 

 of isothermals. The recorded lines of equal temperature show 

 that the various lines of heat, as they make westing from the 

 eastern coast of the continent, change in summer to curve up- 

 wards from the Gulf of Mexico in a northwesterly direction to a 

 point in latitude 50, longitude 1 10 west. At this point, the mean 

 summer temperature is 70° F., while at Winnipeg, on the same 

 parallel of latitude, 1 50° further east, the temperature is but 65°. 

 Tracing these isothermals still further north, the line of greatest 

 heat passes near Fort Vermilion in latitude 58° 24' and longitude 

 116° 30 west. I may mention that, at this point, I found barley 

 cut on August 6th, 1875, and wheat almost ripe. Still further 

 north and west, the table shows that Fort Simpson has a mean 

 summer temperature of 61° 8' F. Turning to the west coast, the 

 isothermal lines commence to turn northward from the Gulf of 

 California and, for a time, skirt the western side of the Rocky 

 Mountains. On reaching the low point of the chain, between 

 latitude 41° and 45°, they turn to the east, cross the mountains, 

 and strike the Dominion boundary of the 1 1 5th Meridian. These 

 westerly currents, named the "Chinooks," have been known to 

 cause a rise in the temperature of 60 degrees in a few hours. When 

 in that country, I enquired from a half-breed, about their effect 

 on the snow. His reply was: "Chinooks lick up snow, water, 

 and all." 



"After crossing the Rocky Mountains, the thermometric 

 current of the west meets that of the east at or about the Hand 

 Hills in Latitude 51° 20', Longitude 112°. There, in 1879, I 

 found that, for days together, during August, the thermometer 

 in the shade, registered from 87° to 92° F. From the Hand Hills, 

 the united currents, following their resultant direction, carry the 

 temperature of latitudes, extending almost to New Orleans, over 

 the North West and confer on it the blessings of a climate, not 

 only exceptional as regards character, but productive of results 



