SALMON STAIRS. 265 



where most water flows over. In this trough are fixed 

 stout, transverse hoards or steps, properly supported, to 

 resist the weight of the stream. Stone will he found 

 cheapest in the long run. These hoards do not of course 

 continue entirely across the trough, so as to har the fish 

 out; hut an opening is left at either side alternately, 

 through which the fish can rush. 



The accompanying diagram will illustrate the manner 

 in which this is contrived. The arrows denote the 

 direction of the stream, and it will he seen that "behind 

 every step the salmon can find a safe resting-place. 

 When the fall is very heavy and perpendicular, it is 

 less expensive to make a cut round it, which is done 

 by digging a passage from some distance above it, as 

 close to the foot of the fall as possible, — this cut, of 

 course, being broken up by steps into a series of small 

 falls, easily practicable to the fish. This plan was 

 adopted at Ballisodare and at Lough Mask. 



