82 



Types of Aquatic Environment 



minute icicles are forming and their tips are being broken 

 off by the oscillations of the current. These broken 

 tips constitute 

 the rubble. 

 They are some- 

 times remark- 

 ably uniform in 

 size— those form- 

 ing when this 

 picture was 

 taken were 

 about the size 

 of peas — and 

 though small 

 they are the 

 tools with which 

 the current does 

 its winter clean- 

 ing. In the 

 ponds formed by 

 damming rapid 

 streams this rub- 

 ble accumulates 

 under the solid 

 ice. 



''Anchor ice*' 

 forms in the 

 beds of rapid 

 streams, and 

 adds another 

 peril to their in- 

 habitants. The 

 water, cooled ^ ^, . ., ^ . , t. „ ^ « 



1-1 J.1 r 1^10,23. 1 he ice veil on Triphammer Falls, Cornell 



pelOW tne ireez- University Campus. The fall is at the left, the 



inSf point bv con- Laboratory of Hydraulic Engineering at the right 



, f^ •,-\,-r • in the picture, the only open water seen is in the 



tact With tne air, foaming pool at the foot of the fall. 



