58 FISH FARMING '. 



through the screen G, in the direction of the arrows, b b b b, 

 and flows out of the apparatus in the direction of the arrows 

 c c, either into the next po'nd or into a surplus water channel. 

 Any debris is left on the top of the screen G and removed by 

 an assistant when necessary. The screen does not often re- 

 quire cleaning, as the debris is carried against the partition E, 

 where it accumulates, leading the greater portion of the surface 

 of the screen quite clear. It will at once appear clear that 

 no fish can pass this box screen either up or down. Of course, 

 it cannot be used to empty a pond. It is not intended for that 



AN OVERHEAD HORIZONTAL BOX SCREEN. 



purpose, and is, preferably, used in connection with a 

 controlling sluice. The inside and outside and all fittings 

 should be charred a,nd covered with black varnish before being 

 put into position. 



The illustration of an overhead horizontal box screen is a 

 photograph of a moist useful contrivance for supplying water 

 absolutely free from debris to fry ponds. The system hero 

 shown keeps all debris 001 the move, and, properly set up, in 

 the manner now described, it should work without choking for 

 months. It is in the form of a long trough, and two inches 

 above the bottom of this trough a false bottom of perforated 

 zinc runs the entire length. Holes are made in the wooden 

 bottom of the trough, and at the bottom of the front side at 



