ATMOSPHERE . 31 



the atmosphere, leaving the air fresh, clear, and cool. 

 Along with the dual particles, and often carried by 

 them, a iv many small bodies called bacteria. They 

 arc living bodies, but such small ones that they can be 

 seen only by means of a good microscope. Some bac- 

 teria came disease in plant- and animals, but others are 

 v< r\ beneficial t<> both, as you will learn later on. No- 

 khe mold which forms on starch paste when it is 

 pen to the air. This mold is caused by bacteria, 

 which teed on the paste. If some substance poisonous 

 to bacteria be mixed with paste no mold will form, and 

 the paste keeps till it dries up. Oil of winfc 

 poisonous to certain bacteria, and is much OSed for pre- 

 ing starch past 

 32. Meteorology. — Wind, rain, and sunshine do not 

 come and go by chance; their movements are regulated 

 by lav ad IS those changing day to night and 



night back to day again. ' By studying these laws we 

 may learn when to expect a change of weather. Scat- 

 tered over our country are many weather hureaus, where 

 men employed by the government are constantly watch- 

 ing and recording the changes and movements of sun- 

 ihine, wind and rain, which changes go to make Dp 

 what we call weather. It Is very true that man cannot 

 control the coming and going of sunshine, wind, and 

 rain, but the successful farmer knows how to regulate 

 hi- fanning to suit the weather, and is always prepared 

 to meet the changes which are constantly occur r in g. 

 Some knowledge of meteorology — the science of the 

 t — is necessary in successful farming. This 

 knowledge usually comes from years of experience and 



