ECOLOGY — INTERPRETATION OF ENVIRONMENT 375 



1 [ 



V. 



^ 



The Drink 



OF THE 



Grasshoppers 



evening, after the 

 lowering of the sun, 

 the gathering dew 

 in Httle spheres of 

 crystalHne pureness at the 

 extreme tips of the grasses. 

 To observe this beautiful 

 phenomenon, which is com- 

 mon in July, one has but to seek a field where grass, wheat, 

 or rye is growing. Then, getting near to the ground and 

 looking upward toward the west, so that the afterglow of the 

 evening sky will light the tiny water spheres, they are here 

 seen to best advantage. 



The illustration figures the dew as I witnessed it on July 

 twelfth, at 7.30 p.m. As shown in the drawing it often fur- 

 nishes drink for insects, especially grasshoppers. The dew is 

 produced by the lowering temperature of the grass blades 

 below that of the dew point in the surrounding air, causing a 

 condensation of moisture on the grass tips. This condition is 

 favored on still nights more than on windy ones, because 

 circulating currents keep the air from arriving at dew point, 

 by bringing variable warmer air in contact wuth the objects. 



