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FILTER. The filter is a box six feetjong by one and 

 a halt feet wide and one and one-half feet deep ; in 

 which four or five flannel screens can be placed through 

 which to filter the water before it passes into the troughs. 

 The coarsest and cheapest red flannel is the best. It will 

 rot and must be renewed once or twice in a season. 

 Red flannel will last twice as long as any other. The 

 flannel should be tacked on frames running in grooves 

 set at an angle of forty-five degrees, (the top down stream) 

 so as to expose as much surface as possible to the water. 

 If the hatching house is small, the filter may be placed 

 outside, but is better under cover. If the spring is well 

 protected the screens will not need cleaning very fre- 

 quently. They should be cleaned as soon as they look 

 dirty, however often that may be, and can be cleaned 

 best by being taken out and washed with a soft brush. 



A filter can be made with sponges placed in a box 

 with the water introduced at the top and brought out at 

 the bottom, provided there is fall enough. The box 

 should be about thirty inches long and twelve wide, and 

 a board perforated with holes should be placed below the 

 sponges, and leaving a space between them and the out- 

 let pipe. This will answer on a moderate scale where 

 only a small amount of water is used, and only a few 

 hundred thousand fish hatched, and the sponges will 

 remain clean for months. There should be an overflow 

 pipe from the top to make sure that there is a sufficient 

 supply of water and to carry ofl the surplus. 



Sediment falling on the egg keeps the water off and 

 destroys its life as effectually as being buried in the 

 giound would destroy a man's life. If sediment falls 

 upon the eggs it may be removed by gently agitating 

 the eggs with a feather, or better still, by creating a cur- 

 rent in the water with a leather, which current the eggs 



