184 FISH CULTUEE 



The water is flowed into one end of the top 

 trough, thence through those below and the 

 jars, until it emerges into the fry-tanks or the 

 sewer. Thus the water is used over and over 

 again not only for the hatching of the eggs but 

 for holding of the fry. 



When brought into the house the water may 

 be run directly into the top trough by means 

 of a pipe, or first flowed into a supplying tank 

 or trough and thence by pipe into the battery. 

 Each trough of the battery must be of the same 

 length, although the ends must not line from 

 the bottom to the top, but be staggered end- 

 wise, the top trough being short at the end 

 farthest from the supply-pipe. The purpose 

 of the staggering is to allow the water to fall 

 from one trough to the other. To facilitate 

 the fall, the top of each end of the trough is cut 

 for the depth of an inch, to which is set nearly 

 perpendicularly a japanned tin lip. The stag- 

 gering need be only just enough to allow the 

 water to fall from one trough to another with- 

 out spilling on the floor. 



The troughs are held in place by standards, 

 three inches by four, reaching from the floor 



