384 Fisumye in AMERICAN WATERS. 
fore nearly all husbanded after it passes through the boxes 
by catching it in a marble trough and sending it back to the 
supply reservoir by a pipe from a hydraulic ram, or a turbine 
like that by which many reservoirs are supplied from rivers 
or springs. These plans of aeration enable fish-culturists to 
run the same water several times over the hatching-boxes ; 
but it is thought by some professors that—for perfect safety 
to the ova—the water should be continually renewed, and not 
flow over them a second time. ° 
In establishments of fish-culture like the government one 
at Huningue, they endeavor to imitate nature more perfectly 
than it can be done by a tier of boxes. They therefore build 
a race-way thirty feet long, 
deep, as the trout-brook, and the fountain of equal tempera- 
a yard wide, and eight inches 
ture feeding it by pipes is the spring. In this race-way are 
placed crosswise numerous trays of terra-cotta, glazed inside 
to prevent contact of conferve with the ova, and in which, to 
a frame of wood, glass tubes are fitted, and called a gril, the 
French name for gridiron. The tray is six inches wide, four 
inches deep, and as long as the race-way is wide. Both the 
tray and the grille may be moved with ease to another race- 
way, or the grille may be moved to clean the bottom of the 
tray or for other purpose. The following cut may help illus- 
trate. 
