WATER SUPPLY FILTER. 23 



true, so that when the water is running it will form an 

 equal current over every part of each strip along the whole 

 length of the trough. If the water runs unevenly the eggs 

 will be washed into a heap, and many of them spoiled for 

 lack of a proper circulation of water around them. This 

 supply of water will be sufficient until tlie eggs are hatched 

 out, when a somewhat larger supply can be allowed. The 

 water should be brought directly from the spring in a pipe 

 of some kind, in order to preserve the proper temperature 

 and keep the water as free from sediment as possible ; and 

 for the same reason the spring should be walled up to its 

 smallest possible dimensions. If any surface water natu- 

 rally runs into the spring, a ditch should be dug around 

 the spring to lead it off. If the muddy surface water is 

 suffered to run into the spring which supplies the troughs, 

 the screens will very soon be choked up, and the sediment 

 will find its way into the troughs in spite of all precautions 

 and destroy the eggs. 



Filter. — The filter is a box six feet long by one and a 

 half 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 tlie troughs. The 

 coarsest and cheapest red fiannel 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 to frames running in grooves set at 

 an angle of forty-five degrees, (the top down stream) so as 

 ta 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 frequently. 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. 



