212 CLIMATOLOGY. 



No. II. 



CLIMATOLOGY. 



Snow Line. — Ground Ice. — Therniometrical Observations in the Valley 

 of the St. Lawrence. — Comparative Temperature of the Two Sides 

 of the Continent. — Phenomena of the Seasons at Penetanguishene : 

 At Fort William : At Fort Vancouver. — Thermometrical Observ- 

 ations in the Valley of the Saskatchewan. — On the East and West 

 Sides of the Continent in that Parallel. — Phenomena of the Sea- 

 sons at Cumberland House : At Carlton House : At Marten's Falls 

 on Albany River. — Thermometrical Observations on the Missinipi 

 and in the same Parallels on the East and West Sides of the Con- 

 tinent. — Thermometrical Observations in the Valleys of the Mac- 

 kenzie, Yukon, and Pelly. — Progress of the Seasons at Fort 

 Franklin. — Thermometrical Observations on the Arctic Seas. — 

 General Remarks. — Nocturnal Radiation. 



The remarks which follow on the climate of North 

 America have reference especially to the districts through 

 which the Expedition travelled, some general facts 

 being, however, illustrated by observations made in other 

 quarters. 



The course of the snow line has always engaged the 

 attention of travellers, who have ascended high mountain 

 ranges, or penetrated into Polar regions. Nowhere on 

 the route of the Expedition is the snow permanent ; not 

 even on the summits of that part of the Rocky Moun- 

 tains which skirts the Mackenzie. Snow may indeed be 

 occasionally found in summer which has drifted into some 

 narrow ravine, or under a high cliff with a northern ex- 

 posure ; but these patches are of small extent, and have no 

 general influence on the temperature of the district in 

 which they occur. 



