Evaporation. 335 



a beautiful lace-like pattern beneath, their own 

 shadows glide along the sand. That sand, too, is 

 arranged by the ripple in slightly curved lines. 

 These wave-marks, though so slight that with the 

 hand you may level fifty at a sweep, have yet 

 sometimes proved durable enough to tell the stu- 

 dent after many centuries where water once has 

 been. Under the foundations of some of the oldest 

 churches the monks loved to build near water 

 the wave-mark has been found on the original 

 soil. 



In a hollow of the old oak starlings have made 

 their nest and reared their young in safety for several 

 seasons. They seem to understand that the water 

 gives them protection, for their nest would not be 

 out of reach were the tree on land. 



Just as at the seashore the wave curls over in an 

 arch as it comes in before dissolving in surf and 

 spray, so here, when a gale is blowing, these lesser 

 waves, as they reach the shelving strand, also curl 

 over. In the early morning, as the sun begins to 

 acquire some strength, the white mists sweep over the 

 surface and visibly melt and disappear. One hot 

 summer when the lake was full, and kept so artifi- 

 cially by the hatches and dams, I found by observation 

 that its level sank nearly half an inch every day. 

 This was the more striking because there was at the 

 same time an influx more than enough to repair the 

 loss from leakage. Now the evaporation of half an 

 inch of water over such a width of surface meant the 

 ascension into the atmosphere of many thousands of 

 gallons ; and thus even this insignificant pool might 

 form a cloud of some magnitude in a few days. 



