96 



the passing current and suffocated. In troughs the water 

 strikes the body of eggs on the edge and then simply 

 passes over and along them, not penetrating, but merely 

 coming in contact with their surface ; in the Holton box, 

 the water enters every part, works up between every egg, ' 

 and even it these are piled two or three deep, will vital- 

 ize all of them. 



It must be remembered that impregnated eggs re- 

 quire the oxygen in the water as much as the living fry 

 and will smother if shut out from it. Anything that 

 does this, whethei it be dirt, sediment, insufficient cur- 

 rent or other eggs will destroy them and no plan has 

 yet been invented which so absolutely prevents this 

 danger. The economy of room is another important 

 consideration where fish culture is to be prosecuted on 

 a large scale. As we have said, eight boxes will contain 

 and hatch two-millions of white fish eggs, and an equal 

 number of boxes of trout eggs will supply the place of 

 a large establishment laid out in the old fashioned and 

 ordinary method. 



The openings through the wires are not round or 

 square but a long narrow parallelogram, differing in 

 width for the different sizes of eggs which are to be 

 hatched. To understand this it is only necessary to sup- 

 pose the wires stretched on the trays at proper distances 

 from one another, and then bound together by cross 

 wires at three-quarters ot an inch from one another, or 

 sufficiently near to hold all securely together. The 

 wires for white fish eggs are nine to the inch ; those for 

 brook trout are eight to the inch ; seven for salmon 

 trout, and six and a halt for salmon. In like way they 

 can be adapted to any other species of fish that it is pro- 

 ' posed to hatch. They could be used for shad where it 

 is not desirable or convenient to use the regular shad 



