,,, 



THE WEATHER, AND WEA-THKR PROPHETS. l6l 



takes its place in its new situation as very cold air, with- 

 out further tendency to rise. But the vapour so chilled 

 loses its vaporous state, and condenses in the manner 

 above stated ; leaving only so much uncondensed as can 

 remain vaporous under that temperature and pressure. This 

 is the origin of those continual and violent tropical rains 

 which always accompany the vertical sun, and its near 

 neighbourhood, and of which we feel the influence, 

 though slightly, in our wet Julys. The vapour being 

 thus arrested in its upward progress, the whole of the 

 evaporatory process we have just described, however 

 tumultuous in its origin, is confined to what may be con- 

 sidered comparatively the lower strata of the atmosphere. 

 But these become in this manner saturated with moist- 

 ure ; and when carried into the general circulation, con- 

 vey it either as cloud or as invisible vapour to the 

 farthest regions of the earth. 



(24.) Besides the evaporation produced by the direct 

 action of the sun, a vast amount of moisture is taken up 

 by the air immediately from the sea and land over which 

 it passes in its indraft towards the Equator as a trade- 

 wind. Coming from a colder region to a warmer, and 

 acquiring heat as it advances, its capacity for receiving 

 and retaining moisture in an invisible state is continually 

 increasing; and hence, even during the absence of the 

 sun in the night hours, it is constantly absorbing moist- 

 ure ; which it carries along with it, and delivers, as 

 a contribution of its own collecting, into the general 

 ascending mass, to be handed over in the returning 

 upper current into the circulation. Hence it arises that 



L 



