140 THE WORE.BL 



minute, aqueous globules remain suspended. These are found tor 

 be made up of hollow vesicles, filled with air like a soap bubble ; 

 and as the air included, is rarefied by the latent heat when the va- 

 por is condensed, the weight of these vesicles becomes less than 

 the weight of an equal bulk of air, ami therefore they rise or float, 

 forming a cloud. When the air within these vesicles bursts, the 

 drops of rain are formed, which are changed, according to the 

 sircumslances attending their formation, as regards rapidity and 

 copiousness, or the state of the medium as to heat, into hail or 

 snow. In order for the precipitation of moisture necessary to- 

 form rain, hail, or snow, contending currents must bring vast 

 fields of air of different temperatures over a given spot, as for 

 example, when a warm south-east wind encounters a cold north- 

 wester. In some parts of the world, as in Egypt, part of Chili, 

 and Peru, it seldom rahis, for there the winds usually blow in 

 one direction. 



Snow is formed by the crystalization of aqueous vapor in- 

 stead of its formation into drops. It is thus converted into a 

 white downy substance, which falls gently to the surface, forming 1 - 

 in winter a warm covering, confining effectually the heat of the 

 earth. The snow huts of the natives of Labrador are said to be- 

 quite warm. Below are figured some of the beautiful forms which 

 the snow crystals assume in cold climates, 



Hail is forme 1 by drops of rain suddenly congealed during their 

 till, by passing through, a lower stratum of dry and cold air. The 



