ARTIFICIAL FISH PROPAGATION. 399 



cloth will permit say 2 feet. Strips of three-qnarter-inch 

 stuff must be nailed to the bottom of the race for the screens 

 to rest on, in such a manner that they will be raised one quar- 

 ter of an inch above the gravel on the bottom. This is done 

 to give good circulation to the water under the spawn as 

 they fall on to these wire screens. These screens must be 

 laid the whole length of the race, side by side, to catch the 

 spawn as it is deposited by the parent trout. 



"Now place over these another set of screens made of coarse 

 wire-cloth, of about two or three meshes to the inch, so that 

 the spawn will drop through easily. These screens must be 

 nailed on frames of the same length as the others, but of two- 

 inch stuff, and as wide as the cloth will permit. These screens 

 must be strong enough to hold 2 inches of well-washed coarse 

 gravel from three quarters of an inch to 2 inches in diameter. 

 They should be so large that there will be interstices between 

 the gravel large enough to let the spawn pass down, if neces- 

 sary, to the lower screen. The upper screens should have han- 

 dles on each end to lift them by, as they will have to be taken 

 out and replaced every few days during the spawning season. 



"When these two sets of screens are placed the whole length 

 of the race, and all is complete, the water will pass over all, 

 2 inches deep at the supply end, and 15 inches deep at the 

 lower end, with a moderate current through the whole race. 

 The reader will perceive by the description and diagram that 

 there is one inch of space between the two screens to hold the 

 spawn as they are deposited by the parent trout, with a gen- 

 tle current passing over and under them, and that the upper 

 screen prevents the spawn from being destroyed by trout 

 and insects, so that they are perfectly safe until removed to 

 the hatching-box. 



O 



"When the trout is ready to spawn she will enter the race 

 from the pond and prepare her nest. This she does by whip- 

 ping all the sediment from the gravel with her tail, and then 

 she whips or digs a hole in the cleansed gravel about 2 inches 

 deep, or down to the upper screen, and about 4 inches in-di- 



