WATER CONDENSING HIGH IN THE AIR 



33 



FIG. 23. What kind of clouds forms nearest the earth? What kind of clouds 

 forms farthest from the earth? When would a cloud be called a fog? 

 What kind of clouds has the greatest range of heights? What kind of 

 clouds have you in the sky to-day? What is the average height? What 

 do they predict? 



WATER CONDENSING HIGH IN THE AIR 



Why Air Loses its Moisture. Warm air can retain a greater 

 quantity of vapor in an invisible state than cold air. 



At freezing point (32 F.) the air can sustain -^ of its weight of 

 transparent vapor, and for every increase of 20 its retaining capac- 

 ity is practically doubled. Thus a cubic foot of air saturated with 



