JULY 135 



and it is this which keeps us comfortable. 

 At first sight it seems a poor plan to cool the 

 body by pouring warm water on it; and so 

 it is, unless that water will evaporate. It 

 takes as large an amount of heat to make 

 water evaporate as it does to boil it. But 

 we must distinguish between the amount 

 and the degree of the heat. A lower degree 

 of heat spread over a longer time will evapo- 

 rate the water that a higher degree would boil 

 in much less time. Now, the heat to evapo- 

 rate the perspiration is taken chiefly from our 

 bodies, which thus naturally become cooler. 

 On days when the air has taken up all the 

 water it will hold, we perspire in vain. The 

 moisture gathers in beads when it should 

 slowly disappear in the air. These are the 

 days we call sultry, and they are more un- 

 comfortable than merely hot days though 

 the temperature be not so high. 



BIRDS IN JULY 



The birds particularly seem to feel the 

 heat. In every little stream they are splash- 

 ing and spattering the water over their warm 



