


A FISH FARM. 205 
The first requisite now is a supply of pure spring water 
for hatehing the eggs,— neither too warm nor too cold. 
From 45° to 509 is the best. Every degree warmer or 
colder will make from six to eight days difference in the 
time of hatching. From 37° to 54° is considered the limit 
within which to hatch trout. By a calculation in Mr. Nor- 
ris’ book (“American Fish Culture”), it will take one hun- 
dred and sixty-five days with water at 37°, and thirty-two 
days with water at 54°. 
The hatching house in the establishment we have spoken 
of is a wooden building twenty feet long by twelve feet 
Fig. 40. 









wide, into which water is admitted about three feet above 
the level of the floor, from springs immediately in the rear, 
enclosed in sunken tanks as before described, and covered 
So as to be out of reach of cold or heat. To enable the 
water to be brought in at this height from the floor, the 
house is sunk three feet in the ground, and the boards are 
covered with a heavy coat of pitch inside and out, to a point 
Above the level of the surrounding ground to prevent their 
rotting. The amount of water now used in the house is 
What will flow through two faucets, one inch in diameter, 
with a moderate pressure. This is led in the first instance 
Into a straining trough (Fig. 40, a), running across the width 
of the building, where it passes through flannel strainers (4) 
to insure its purity. It then flows into a distributing trough 
(^), which is parallel to the straining trough and a few inches 
lower, from which, by means of faucets, it is let on to the 
hatching troughs in such quantity as may be best. 
