RESULT OF STUDY AND GI&IUS. 



413 





BALLYSADAHE SALMON-PASS. 



A. Face of Dam. B. Entrance to the Ladder, easily found. C. Kesting-pool, of from 

 one to two feet depth. D. Exit from Ladder above the fall. 



The steps in the ladder extend three fourths its width, leav- 

 ing the stream and eddies represented. This sketch illus- 

 trates a very important principle, which can be varied at 

 pleasure. The gradient of a salmon-ladder should really not 

 be less than 1 in 9 or 10, and 1 in 12 is better still. The 

 chambers between the steps are greatly improved if the bot- 

 tom instead of being all upon the same slope as the gen- 

 eral gradient of the ladder is broken into steps, so that the 

 water is deeper immediately behind the steps, or little steps 



