46 



eggs are to be hatched, the inconvenience of Btooping to 

 caro for them is very great. 



Water Supply. — From the filter the water runs into 

 the distributing trough or pipe, which runs along the 

 head of all the hatching troughs. The water may be 

 let into the hatching troughs by faucets, or through 

 holes cut into the trough. These holes should be cov- 

 ered with netting, or the young fish will run up out of the 

 troughs into the filter, or coarse gravel may be heaped 

 up at the head of the trough through which the water 

 will run, but through which the young fish cannot work 

 their way. The supply of water for one trough should be 

 equal to that coming through a three-fourth-inch hole with 

 three inches head ; just enough to make a gentle ripple 

 over the cross-pieces. Be careful to get the troughs 

 level cros'sways, and the strips true, so that when the 

 water is running it will form an equal current over 

 every part of each strip along the whole length of the 

 trough. If the water runs unevenly the eggs will be 

 washed into a heap if they are being hatched on gravel, 

 and many of them spoiled for lack of proper circulation 

 of water around them. This supply of water will .be 

 sufficient until the eggs are hatched out, when a some- 

 what larger supply can be allowed. The water should 

 be brought directly from the spring in a pipe of some 

 kind, in order to preserve the proper temperature and 

 keep the water as free from sediment as possible; and 

 for the same reason the spring should be walled up to its 

 smallest possible dimensions. If any surface water natu- 

 rally runs into the spring, a ditch should be dug around the 

 spring to lead it off. If the "muddy surface water is 

 suffered to run into the spring which supplies, the 

 troughs, the screen will very soon be choked up, and the 

 sediment will find its way into the troughs in spite of 

 all precautions and destroy the eggs. 



