FOR PLEASURE AND PROFIT. 127 



should one be needed, then proceed to make it after the fol- 

 lowing 1 manner : 



Form the box of strong wood planks, carefully tongned, 

 grooved, bolted, and screwed together, and well char and 

 varnish it inside after making. Fig. 27 is a plan of such a 

 box, and Fig. 28 is a section of the same through a line D E of 

 Fig. 27. The water supply enters 1 the hatchery, and is con- 

 ducted to ths filtering box by an independent pipe. It is 

 permitted! to fall into the box at the upper pant, marked F F, 

 in Fig. 28. It passes through the flannel screens, marked A, 

 in the direction shown by the arrows', and flows into the dis- 

 tributing box by way of the outlet, the position of which is 

 marked at c. This outlet is plaioed in such a position that it 

 .-G 



Fig. 28. Longitudinal Section of Filtering Box. 



ensures the water being kept at a.n average height shown by 

 the line F F F, in Fig. 28. At B is provided 1 ai plug-hole and 

 plug ; this for the purpose of emptying the filter for cleansing 

 purposes. Such operation should not be often necessary, and 

 it will not be if the screens are carefully looked to, as these 

 latter naturally collect most of the sediment. The box is 

 provided with a lid, marked G, which should be kept in posi- 

 tion at all times other than those during which the screens 

 require attention. This i:di has an aperture cut in it at the 

 upper end to permit of the water flowir-g or, rather, falling 

 into the box when the lid is on. A similar aperture occurs 

 in the case of the lids to the distributing box, and also the 

 hatching boxes. It requires to be of sufficient size to guard 

 against any of the waiter splashing on the lid and so to the 

 floor, being thus lost so far a supply is concerned, beside 

 causing an unnecessary mess. The screens are formed from 

 wood- frames, on which is stretched, some coarse flannel. They 



