584 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



mit a free passage of the young fish, are successively placed, one above 

 the other, in the boxes, until the same are nearly filled — each one of these 

 sieves having its proportion of eggs deposited thereon. A pan, F, made 

 of perforated sheet-metal, is then placed as a cover to prevent the eggs 

 from floating. The hatching-boxes, being thus prepared, are placed one 

 in each compartment of troughs C, and with one end resting against 

 that side of the compartment whence the water is received. A cross- 

 bar, G, is then inserted into small slots e in the sides of the troughs, and 

 resting upon the tops of the boxes prevents them from floating when the 

 troughs are partially filled with water. These cross-bars are provided 

 with feet/, so adjusted that, when the bar is in place, the feet will rest 

 against the perforated cover and prevent it from floating. When all the 

 boxes have been thus placed and secured in the various successive com- 

 partments of the troughs, the water is let on through the pipes or fau- 

 cets hereinbefore described as leading from the tank B, and falls on to 

 the perforated covers of the boxes in the first compartments of the 

 trough, and by means of the perforations in the covers is equally dis- 

 tributed over their surfaces, and runs down through the eggs upou the 

 sieves below, supplying them with constantly-changing fresh water, and 

 washing the eggs thoroughly, carrying down any sediment or impurity 

 and depositing it upon the floor of the trough. As the first compart- 

 ments fill with water, the waste-ways 1) allow it to pass on to and through 

 the boxes in the next compartments of the trough, and so on, succes- 

 sively, until the water is finally discharged out of the hatching-house in 

 any convenient way, and at the end opposite the tank. Great care must 

 be taken to so arrange the waste- ways that the water will be discharged 

 from one compartment into the next succeeding one before it reaches 

 such a depth that it would flood or run over the sides of the hatching- 

 boxes. At its lower end each one of these water-ways is provided with. 

 a perforated or wire gauze screen, /i, to prevent the possibility of the 

 fish, when hatched, passing from one compartment to another. When 

 the hatching is complete, the cover may be removed from the boxes and 

 the young fish removed at will. 



Many eggs, in the process of hatching, die, and it becomes necessary 

 to remove the dead eggs to prevent injury to the others. To accomplish 

 this, near each series of comi)artments there is placed a shallow trough, 

 H, into which the water is fed from the tank B through the faucet a', as 

 shown. An operator removes one of the sieves from the hatching- boxes 

 and places it in the trough H, through which the water of the same tem- 

 perature flows from the tank, and of suflicient depth not to float the eggs. 

 The dead eggs are removed in the usual way, and the sieve replaced in 

 the hatching-box. The screen h is placed across the discharge-end of 

 the water-ways, and is to prevent the small fish from ascending the cur- 

 rent. Ordinarily screens are so placed and the hatching-troughs so ar- 

 ranged that the fish are carried down with the current against the screen, 

 choking the same, and damming the water until it overflows, carrying 

 with it great quantities of fish, which are thus lost. 



