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CHAP. XLL 



Climate of the Laurentides and the Prairies. — Frozen Lakes. — Mean 

 Annual Temperature. — Arid and Humid Region. — Sources of Humidity. 

 — Aridity West of the 98th Meridian. — Mississippi Valley. — Arid Region 

 of the United States. — Humid Region of the "Valley of Lake Winnipeg. — 

 Causes of. — Elevation of the Country. — Humid Pacific Winds. — North- 

 easterly Current. — The Arid Region. — Prevailing Winds. — Source of the 

 Humidity. — Rocky Mountain Plateau. — Depression in.— Table of Eleva- 

 tion of Plateau and Passes. — Hail Storms. — Thunder Storms in 1858. — 

 Progress of Dimes. — Summer Surface Yfind. — Meteorology of Red River. 

 — Winter Temperatures. — Winter Temperatures at Montreal. — Cold 

 Terms. — Quebec Temperatures. — Climate of the South Branch of the 

 Saskatchewan. — Limit of permanently frozen Soil. — Growth of Forests. 

 — Tail of the Prairies. — Prairies Converted into Forest Land in Missouri. 

 — Character of the Great Plains in the United States. — Major Emory's 

 Statement. — Auroras. — October 2nd. — October 27 th. — The Twilight 

 Bow. — Indian Summer. 



The climates of Canada and Rupert's Land under the 

 same parallels of latitude, vary to a considerable extent 

 with the rock formations of the country. Throughout 

 the undulating region of the Laurentides, between Lake 

 Superior and Lake Winnipeg, the proportion of water to 

 dry land is about one to two, not collected into one large 

 water area, but distributed over the surface of the country 

 in the form of countless thousands of lakes, ponds, and 

 marshes. The intense cold of winter is sufficient to 

 solidify the deepest lakes for a depth of several feet, and 

 the thawing of so much ice in spring has the effect of 

 absorbing and rendering latent the heat which would be 



VOL. II. A A 



