THE SPAWNING EACE. 71 



made of any -length from four feet to sixty feet, or 

 even longer, and of any width from two feet to six 

 or eight. If it is made very wide, an additional 

 longitudinal support must be provided for the re- 

 volving screen. We recommend the following 

 dimensions for speckled trout races : two feet wide 

 and from ten to twenty feet long ; or four feet wide 

 and from twenty to forty feet long. The upper 

 screens may be made in convenient sections, the 

 whole width of the box, and six or eight feet long. 

 The screens F and D are so made that while a 

 full current is permitted to flow over the upper 

 screens (A), only a gentle current can flow through 

 the under part of this box. This current is meant 

 to be so regulated that when the pan (C) is placed 

 about an inch from the turning roller, all the small 

 stones which the trout may whip through the up- 

 per screen will fall short of the pan ; the eggs, 

 being lighter, will be carried by the current into 

 the pan, while a great part of the dirt, etc., which 

 may collect on the under screen will be carried up 

 over the pan and entirely out of the box. The 

 revolving screen may be made of tarred muslin or 

 mosquito netting. But wire cloth (of ten or twelve 

 meshes to the inch) keeps much the cleanest, and 

 we are inclined to think it best for the purpose. We 

 make our aprons half wire cloth and half tarred 

 muslin, furnishing the wire only with cross-bars 



