72 DOMESTICATED TROUT. 



" These last boxes are filled with several screens, each 

 containing many thousand eggs, and may be of sufficient 

 capacity to hatch an almost unlimited number of eggs. 



" Over these screens, and after the eggs are equally dis- 

 tributed over them, there is placed a finely perforated me- 

 tallic plate /?, and the whole is kept in place by a cross-bar 

 C, fastened to the sides of the main trough. These boxes 

 are elevated upon feet to raise them from the floor of the 

 trough, to allow a free passage of water under them, and to 

 raise them above any sediment that may pass through and 

 settle on the said floor. 



" The first screen that lies over the copper cloth is also 

 raised to gain free circulation to the water. The main 

 trough must have a descent of three sixteenths of an inch 

 to the foot to form sufficient fall of water into each separate 

 box to produce a moderate current of water down through 

 the eggs. 



" This arrangement completed, the water is let in at the 

 upper end of the long troughs, upon the perforated cover, 

 which spreads it equally over the whole part of the eggs 

 below, which, owing to the declivity of the main trough and 

 the water-tight partitions in them, causes it to flow over 

 said partition on to the next below, which produces an up- 

 and-down movement to the current running throughout the 

 whole series of hatching boxes, making changes around and 

 through the whole number of eggs in each compartment, 

 constant while in process of hatching. 



" Many more fish are hatched by this process than can 

 be stored and cleansed from their shells and other impuri- 

 ties consequent upon the last stages of hatching ; hence, it 

 becomes necessary to add store room and an additional 

 process for cleansing the fish, when hatched out, from the 

 impurities above named. 



" To remedy this trouble, a series of large tanks, G, H, K, 

 are erected for the reception of the water as it leaves the 



