Trout Breeding. 55 



the screen tight, especially at the bottom, or heads and 

 tails will be wedged in there, and the owners of those 

 heads and tails will die. You will believe more of this 

 the second season when you see how small a pinhole 

 an embryo trout can commit suicide in. Many times I 

 have sifted fine sand along the bottom of such a screen, 

 to keep tails, heads and parts of sacs from getting 

 under it. 



This outlet screen may be of finely perforated tin, one- 

 sixteenth of an inch. Mr. Frank N. Clark used this and 

 recommended it to me, but I did not like it because in a 

 given area the holes were the smallest part. I prefer 

 No. 20 copper wire cloth, or, if of iron wire, to be 

 tarred, No. 16. In wire cloth the "holes" are the largest 

 part of the area, and they last the longest. 



Now that all is ready in the trough, mount it on 

 carpenter's "horses" three, if the trough is not over 

 fifteen feet long and have it exactly level across the 

 bottom, but give it at least half an inch fall in its length. 

 This fall is merely for convenience in cleaning, nothing 

 more. 



I prefer the trays to set flat, on carpet-tack legs, as de- 

 scribed, instead of having them raised on their "hind 

 legs," as some others place them ; but this is a minor 

 point, not worth discussing. 



Let the water run through ; tighten troughs after a 

 day or two by a nail-set and a hammer; and here is 

 where you will learn why the sides of a trough should be 

 nailed to the bottom, for convenience in tightening as 

 well as for increased stiffness. 



Put the hatching trays in the troughs, weight them 

 down with stones until they cease to float, and then you 

 may sit down, light your pipe and say: "Now bring 

 on your eggs !" 



