466 Of the Propagation of Heat 



Is entirely owing to their separation from the neighbour- 

 ing continent by so large a tract of sea ; and in all simi- 

 lar situations, in every part of the globe, similar causes 

 are found to produce similar effects. 



The cold northwest winds which prevail upon the 

 coast of North America during the winter seldom ex- 

 tend above 100 leagues from the shore, and they are al- 

 ways found to be less violent, and less piercing, as they 

 are further from the land. 



These periodical winds from the continents of Europe 

 and North America prevail most towards the end of the 

 month of February, and In the month of March ; and 

 I conceive that they contribute very essentially towards 

 bringing on an early spring, and a fruitful summer, par- 

 ticularly when they are very violent in the month of 

 March, and if at that time the ground is well covered with 

 snow. The whole atmosphere of the polar regions be- 

 Ino-, as it were, transported into the ocean by these winds, 

 is there warmed and saturated with water : and, a great 

 accumulation of air upon the sea being the necessary 

 consequence of the long continuance of these cold winds 

 from the shore, upon their ceasing the warm breezes from 

 the sea necessarily commence, and, spreading themselves 

 upon the land far and wide, assist the returning sun in 

 dismantling the earth of the remains of her winter gar- 

 ment, and in bringing forward Into life all the manifold 

 beauties of the new-born year. 



This warmed air which comes in from the sea, hav- 

 ing acquired Its Heat from a contact with the ocean, is, 

 of course, saturated with water; and hence the warm 

 showers of April and May, so necessary to a fruitful 

 season. 



The ocean may be considered as the great reservoir 



