FORCES AT WORK IN THE ATMOSPHERE. 17 



55. Iii the atmosphere, great operations are going on ; 

 all things are perpetually mingling, or trying to mingle. 

 The winds are blowing, in vast circuits, from zone to 

 zone, bearing heat from the equator and cold from the 

 poles, moisture from oceans, lakes, and streams, and dry- 

 ness from the mountains and plains, and scattering dust 

 and the seeds of plants and the eggs of minute animals. 



Into the atmosphere are continually rising- vapors and 

 exhalations from all moist and all decaying substances ; 

 poisonous gases from the breath of man and other ani 

 mals, and from burning volcanoes and the fires which 

 are kindled by accident, or for the uses of man. All 

 these are constantly striving to diffuse themselves, and to 

 penetrate and mingle with each other and with parts of 

 the solid earth. 



56. The sun is continually darting his rays of light 

 and of heat in every direction, illuminating and warming 

 every thing within the sphere of their influence. Every 

 star, every fire, every candle is doing the same. Oxygen 

 is always tending, with ceaseless effort, to enter into and 

 combine with other things. Every other gas and vapor 

 is, by its nature, diffusing itself in like manner. Water 

 moistens, that is, enters into, every thing with which it 

 can come in contact the air, and all things in it, the 

 earth, and the solid rocks. 



57. And this it does by that force by which particles 

 near each other are drawn nearer. It is this force which 

 makes the particles of water rise upwards from the ground 

 into a heap of ashes or fine sand, and penetrate among 

 the fibres or grain of wood. It is this which draws water 

 up into a tube of glass with a bore as fine as a hair, 

 whence it is called Capillary Attraction, (from capillus, 

 Latin, a hair.) 



