THE WINDS. 119 



phenomenon are the increased saltness of its 

 waters, caused by the evaporation necessary to 

 supply the trade-winds with vapour, and the di- 

 minished quantity of salt in the northern seas, 

 towards which the Grulf-stream flows. We have 

 already referred to the important influence which 

 this ocean-current has in tempering the climate 

 of those lands toward which it tends. Much highly 

 interesting and minute information on this sub- 

 ject will be found in the various works devoted 

 especially to the physical geography of the sea. 

 But it is not requisite to the plan of this work 

 minutely to discuss a subject which not only 

 demands an elaborate disquisition, but is only 

 indirectly connected with the phenomena which 

 it is our immediate object to illustrate. 



The winds or currents of the atmosphere which 

 are now to engage our attention constitute a sub- 

 ject full of interest to those who frequent the 

 beach, and who have opportunities of witnessing 

 the effects which the wind produces upon the 

 ocean. It is a subject also strikingly illustrative 

 of several important physical laws, as well as of 

 the admirable wisdom in which those laws have 

 had their birth. Some general observations on 

 the subject will not be unsuitable before giving 

 our attention to the aerial currents of our sea- 

 shores. 



The winds are either constant, or such as blow 

 always in the same direction, periodical, or such 

 as blow six months in one direction and six 

 months in another, or variable, that is to say, 



I 4 



