78 DOMESTICATED TROUT. 



small a mesh that the eggs will not pass through, but large 

 enough to permit the passage of the fry, which, as soon as 

 they break the shell, are carried up by the current and into 

 the reservoir, from which they may be taken out as re- 

 quired. White fish eggs placed in one layer will number 

 sixty-four to the square inch. Each tray will hold about 

 18,000 eggs, and each box about 325,000. But some of 

 the boxes are made smaller, for the sake of experiment, so 

 that the eight boxes, using (with the reservoirs) a space of 

 sixteen feet long by three feet four inches wide, will hatch 

 about 2,000,000 white fish eggs." 



6. The use of deep trays with the Williamson hatch- 

 ing troughs. This plan was adopted at the United 

 States Salmon-breeding Station in California in 1874, 

 and was found to be, in the writer's judgment, the 

 best thing yet devised for maturing salmon eggs 

 on a large scale for shipment. Not having tried 

 it for trout eggs, I cannot say how it would work 

 with them, but, with proper modifications, I should 

 think it would do very well. The advantages of 

 the plan are that it economizes space and saves a 

 vast deal of trouble in picking over the eggs. 



At my place in California the trays used were really 

 wire-netting baskets, ten inches wide by twenty-four 

 inches long, and deep enough to bring the top of the 

 trays an inch or two above the water, which was five 

 or six inches deep in the Williamson troughs, in which 

 they were placed. Into these trays we used to pour 

 two gallons of salmon eggs at a time. This made the 

 eggs twelve or fifteen tiers deep, and yet they suffered 

 no injury whatever from being so piled up ; one ex- 

 planation of this being that the water all the time 



