384 



FISHING 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 saine 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, a yard wide, and eight inches 

 deep, as the trout-brook, and the fountain of equal tempera- 

 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 confervse 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. 



Fig. 1. Terra-cotta Tray, to fit crosswise in race-way. Fig. 2. Grille of glass tubes, 

 made to fit in the tray. Fig. 3. Race-way, as wide inside as the length of the tray. 



