46 AMERICAN FISH CULTUKE. 



It is better for many reasons, that the supply should 

 flow through earthen pipes or glazed tile ; there is some 

 risk in conducting it through leaden pipe, as the action of 

 certain limestone waters on lead is injurioas, unless the 

 pipe is coated with zinc. 



Although a trough for hatching a few thousand eggs 

 may be placed in the open air if kept covered, it is neces- 

 sary that a number of them should be under the cover of a 

 building of some kind, that the ova may be protected from 

 the weather and the depredations of rats and other animals 

 that would eat them, as well as for the comfort of those 

 who attend to them. A house of rough boards will answer 

 the purpose. A stove is not necessary in the hatching- 

 house unless' the water is very cold. Where the water is 

 as high as 48° or 50° the temperature of the air inside of 

 a close board house will be almost the same, and comfort- 

 ably warm. The windows, or the greater number of them, 

 should be on the north side, if it can be so arranged, so 

 as to admit the light with as little sunshine as possible. In 

 a length of forty-eight feet, three windows are enough, the 

 panes may be eight by ten inches, and the sash two panes 

 high and four panes wide, and may slide horizontally in 

 opening them. Each window should have a curtain or 

 slidipg shutter to exclude the light when it is deemed 

 expedient to do so. 



On the opposite page is a ground plan for a hatching 

 house. Scale, one-sixteenth of an inch to the foot. 



A is the filterer, four feet long, two feet wide, and 

 eighteen inches deep. The three transverse lines repre- 



