48 



will follow, and as they roll over, the sediment will drop 

 off. But the trout breeder has no business to be troubled 

 in this way. If his apparatus is rightly constructed, 

 and his filter properly attended to, there will not be 

 sediment enough in the troughs to hurt the eggs, from 

 the time they are put in until the fish are hatched out. 

 The pipe which is let into the spring should have wire 

 netting around it where the water comes in, to keep out 

 impurities. This netting should be spread out so as to 

 give a greater surface than the mouth of the pipe. If 

 the netting covers only the mouth of the pipe, every 

 speck of dirt which lodges on the netting diminishes by 

 so much the supply of water ; but if the surface of the 

 netting is increased, much of it may be stopped up 

 without lessening the supply of water. The best 

 way is to make a box, say one foot square for each inch 

 of diameter of the " pipe, and run the pipe through a 

 hole in the middle of the board, fitting it well ; then fit 

 a screen of netting on the front side in grooves so that 

 it can be taken out and cleaned. This should be looked 

 alter occasionally, but if the spring is closely walled up, 

 and the netting placed beneath the surface of the water, 

 it will not probably need cleaning through the season. 



Gravel foe Teoughs. — The gravel for the troughs 

 should be quite fine — about the size of peas. It is bet- 

 ter to use wire screens as will be explained hereafter, 

 but where only a few egga are to be hatched and it is 

 important to avoid expensive preparations, gravel will 

 answer. It was formerly used altogether but is now 

 almost wholly discarded. It is better to have it of a 

 unilorm size. Any kind of gravel is good which is free 

 from iron rust, as that kills the fish. If the gravel is of 

 some dark tint, the dead eggs, which turn milk white, 

 will show very plainly upon it, and may easily be picked 



