106 



FISH FARMING 



and lakes.) " The dain itself ought to be of earth only, and all 

 stones, ro'ck, or rubble ought to be carefully picked out before 

 building the dam is commenced. Dams ought to be, across 

 their foot, even in very good holding soil (like clay and loain), 



THE LUNCARTY FISH-PASS. 



at least three times the width of the proposed depth of the 

 pond, and the crown of the dam ought to be, at least, ha.lf the 

 depth of the pond at its deepest part. Even this would apply 

 to comparatively shallow ponds only, say, of not over two 



