FIRST YEAH. 117 



them carefully out of their grooves, and by slightly 

 tapping them against the sides of the sluice-gate 

 all dirt will fall off. If they are strongly made r 

 as they should be, and are not hammered vith 

 violence, they will last for years ; but for the first 

 six months at least the fish screen must not be 

 raised. The larger fragments are to be picked off 

 from it by hand, and a common scrubbing-brush, 

 attached to a handle about two feet long, will 

 either rub through the remainder of the dirt or 

 collect it together so that it can be readily removed 

 with the hands. As previously mentioned, trout 

 in ponds always seek to ascend, and the removal 

 of the fish screen, though but for a moment, is the 

 signal of advance to the fishes of a lower pond. 

 Should any larger fishes be seen in the pond in 

 which the youngest are kept, they must be at 

 once removed, even if it is necessary to kill them 

 in so doing. The number of three month's old 

 fishes which can be eaten in a short time by a trout . 

 of the previous year is enormous. Copper wire 

 only should be used for the fish screens, as iron, 

 however well painted, will rust out in a few months, 

 leaving gaps through which the older fishes can as- 

 cend. Twice a day, morning and evening, should 

 the screens be examined and thoroughly cleaned, 

 and duplicates should always be on hand to replace 

 them in case of accident. 



