56 PRACTICAL TROUT CULTURE. 



cotta can not be relied upon. It is but little 

 cheaper than iron, when the cost and risks of trans- 

 portation are taken into consideration, and we 

 have known it to crumble from the action of 

 frost. The supply pipe is the main artery of the 

 hatching-house, and any derangement may cause 

 the loss of hundreds of thousands of spawn. The 

 spring end of this should project some distance 

 into the water, that the supply may be of the 

 purest, and a perforated filter should be attached 

 to the end. Bored wooden pump logs are the 

 worst means yet devised for conducting water, 

 and should never be used, as we know by experi- 

 ence. 



A two-inch pipe, with a fall of two feet, will 

 supply ample water for the hatching of one hun- 

 dred and fifty thousand spawn, if the trays be 

 used. The trough system will require perhaps 

 one of two and a half inches, or even larger. 



As previously mentioned, all water should be 

 carefully filtered ; this is most conveniently done 

 by means of the filtering-box, located at the ex- 

 treme end of our hatching-house (Fig. 9), the 

 water entering near the center of the box passes, 

 first through haircloth or grasscloth, then through 

 coarse, and afterward through fine flannel. A set 

 of these is placed on each side of the pipe. Our 

 method of attaching the flannel to the frames is 



