62 PRACTICAL TROUT CULTURE. 



As previously stated, no gravel, under any circum- 

 stances, should be allowed in any pond, except 

 that in which were placed the youngest fishes ; 

 but the bottom of the spawning race, of whatever 

 character, should be well covered. Between the 

 head of the race and the pond should be a fall of 

 at least six inches, and should it be so great that 

 it might be difficult for the fishes to ascend, re- 

 course must be had to the fish ladder. This is 

 readily formed by placing across the race boards 

 equal in length to its width, and in width some- 

 what greater than the depth of the water. Wide 

 notches, varying in size according to the amount 



Fio. 10. BOARD FOB FISH LADDER. 



of water, should be cut in these near the end. 

 These boards should be placed across the race, at 

 distances determined by the height of the fall, and 

 so arranged that the notches be on alternate sides 



A 



Fie. 11. FISH LADDER. 



of the stream. A plan of a ladder so arranged is 

 to be seen in Fig. 11. 

 A, A represent the sides of the race ; B, B, B, 



