THE WEATHER. 211 



would hurry with irresistible energy every brook and 

 stream onward in its course, and ere long the work would 

 be done. Every fountain would have failed ; river after 

 river would have left its bed deserted and dry. The 

 meadows and marshes would be drained ; the waters of 

 every lake and pond would have escaped, and men might 

 walk over the dry and dusty bed even of Niagara. 



The consequences to animal and vegetable life need 

 not be described. It requires very little imagination to 

 see that our lovely earth would soon reduce itself under 

 these circumstances to one universal desert ; upon which 

 every plant and every land animal must have found a 

 grave. 



And what was the plan which the Creator adopted in 

 order to avoid this danger ? He spreads over the whole 

 surface of the earth an ATMOSPHERE, transparent, invisi- 

 ble, but producing almost inconceivable effects. It 

 raises the waters from the ocean, whither they are 

 constantly tending, and by its unceasing motions they 

 are borne back to the land where they descend in re- 

 peated showers. By this arrangement, the great object is 

 accomplished, but 1 it is not by a regular and monotonous 

 process. There are a few simple principles, but they 

 produce an infinite variety of effects. 



The plan which will be adopted in this treatise will 

 lead me, in the first place, to detail those general princi- 

 ples upon which all the particular phenomena depend. 

 They are few and simple in character. 



1. TEMPERATURE OF THE AIR. 



(a) Diminution of Heat from the Equator towards the 



Poles. 



Owing to the manner in which the rays of the sun 

 fall upon the different regions of the earth's surface, there 

 is a gradual diminution of heat from the intense, and 

 sometimes unmitigated sultriness of the equatorial 

 regions, to the severe and perpetual cold of the poles. 

 The following interesting description of a scene near the 

 southern pole will give the reader a very vivid conception 

 of the nature and effects of this cold. 



The individuals mentioned in the account belonged to 

 Capt. Cook's celebrated expedition to the Pacific Ocean. 



