442 



THE MOUNTAIN. 



perature.* In Clarke, " On the Sanative Influence of Cli- 

 mate," we have the following table of comparison of mean 

 annual temperature of a number of places nearly the same 

 on the eastern and western hemispheres, and of the differ- 

 ence of this ran ore : 



A number of causes have been assigned for this, and a 

 number of explanations and suggestions made of the ra- 

 tionale of the universally acceded facts in this department. 



In the Physical Atlas of Johnston, we have this sug- 

 gestion : 



"The permanent and drifting ice of the arctic regions essentially 

 contributes to depress the isothermal lines on the east coast of North 

 America to such low latitudes, and to increase the difference of the 

 seasons ; for, while on the European side of the Atlantic Ocean, be- 

 tween the isothermal lines of 40 and 32, the difference between 

 winter and summer amounts to 36 and 40, on the other side, on 

 the coasts of the New World, it amounts to 52 and 54. There is 

 here 14 and 16 difference on the different sides of the Atlantic 

 under some lines of latitude." 



Dr. Drake remarks : 



"On the western side of the continent the high range of the 

 Sierra Nevada cuts off the genial influence of the Pacific Ocean." 



Thus, he supposes the equalizing influence of large bodies 

 of water is prevented from reaching the eastern side of the 



* See one of the leading quotations from Volney ; a rather sharp 

 observation for sixty years ago. 



