42 



The accompanying plate and ground plan will readily 

 show its arrangement, A A are troughs, forty feet long by 

 fourteen inches wide a'nd six inches deep inside measure- 

 ment. These troughs are raised about one foot and a 

 half above the floor for the sake of convenience in attend- 

 ing to the eggs. The .supply pipe, D, sixty feet long and 

 six inches ^deep, carries the water from the stream into 

 the building, where it is received into the feed pioes, 

 CO, in which filters are inserted before the faucets which 

 admit the water into the troughs, A A. These troughs 

 are used now especially for salmon and salmon trout 

 eggs. OO are waste-pipes, by means of which any sec 

 tion of a trough can be cleaned without disturbing the 

 rest. BB are the Holton hatching boxes. 



The eggs are placed on trays made of wire cloth 

 stretched on wooden frames. Each tray is twenty-seven 

 inches long by fourteen inches wide, and will hold in a 

 layer, one deep, 6,272 salmon trout eggs. Instead of 

 using only one layer of these trays, it has been the prac- 

 tice for the last four years to use four layers in the upper 

 sections and five in the lower sections; making lor all 

 the troughs a capacity of 534 trays, or, in round numbers, 

 of three and one-half millions of salmon trout eggs. 



With this illustration, we will proceed to give general 

 direction for the construction and management of a 

 hatching house. 



SIZE AND MAKE. If only a few eggs are to be hatched 

 (say eight or ten thousand) no hatching house is necessary. 

 The troughs may be placed in the open air, in any con- 

 venient place, and covered with a wire screen to keep out 

 rats, mice and ducks. A light board cover must then be 

 laid over them to shed the rain and snow and keep the 

 eggs from exposure to the sunlight. A hatching house 



