AIR AND WATER 27 



atmosphere feels and the probability of moisture condensing 

 in the form of rain than we are with the number of grams 

 of water in a cubic meter. 



27. How to determine whether the air is moist or dry. If 

 one wishes to know whether the air of a room or the air 

 out of doors is relatively moist or dry, he may form some 



i'iu. 1'J. A cumulus cl 



This kind of cloud is formed by the condensation of moisture in columns of rising 



air. Note the characteristic lower edge of the cloud, indicating the level at which 



the dew point is reached 



opinion about it by noting the way it " feels " ; but opinions 

 are inaccurate. Again, one may make use of the ice-water 

 pitcher, and this will give him more accurate information. 

 Thus, if the air contains relatively large amounts of water, 

 the condensation upon the pitcher will be more abundant 

 and will appear more quickly after placing the water in the 

 pitcher than would be true in a dry atmosphere. Thus one 



