84 THE YEAR. 



feelings) were a primary cause ; and not, as it really is, 

 one in the chain of effects, and immediately depending 

 upon some antecedent action, in the same manner as 

 rain, or flame, or any other natural phenomenon. 



This upper current and the under one, which, as it 

 is the only one that we feel, we call the wind, are 

 seldom of the same temperature ; and it has been 

 found by experiment, that the compound that arises 

 from mixing together two quantities of air at different 

 temperatures, cannot retain so much moisture in a 

 state of invisible vapour, as the two can do separately ; 

 therefore the tendency of the adverse currents is to 

 form a cloud, even though the lower one should not be 

 saturated with moisture. With us, the upper or south- 

 west current, originating as it does within the tropics, 

 where evaporation is a maximum, and coming across 

 the Atlantic, may be supposed to be always fully 

 charged with humidity ; but it often happens that the 

 under current is so far from being saturated, that it 

 re-dissolves the cloud, or the lower part of it, as fast 

 as it descends ; and it does this of course the more 

 rapidly that it is in motion, because a new portion of 

 dry air is constantly brought in contact with the cloud. 

 Hence the common saying, that " wind keeps off rain;" 

 hence, also, clouds continue to roll, volume after 

 volume, from one point of the horizon, and the rain, 

 after a time, returns in torrents from the other. Those 

 who live near high mountains are well acquainted 

 with the fact of the rain coming from the upper stra- 

 tum and current of the atmosphere, by the "mantle" 

 or " hat ''of cloud that first envelopes the summit of 

 the mountain. On the east coast, where the east 



