178 How to obtain it. 



over the pipe, which must be fitted into a box. To do this in 

 the readiest way, take any old box and cut a round hole in one 

 side of it to fit on to the end of the pipe. The opposite side of 

 the box should be almost entirely cut away, or it may be knocked 

 out altogether and replaced by perforated zinc. Should it be 

 found needful a finer screen can be fixed inside the box, which 

 itself is to be firmly embedded in the side of the stream from which 

 the water is taken. In some cases it may be desirable to put on 

 a coarser screen outside, and this is easily done by nailing 

 four strips of wood on to the box front, and covering again with 

 coarsely perforated zinc. Of course, where a properly constructed 

 box is used, grooves can be sawn in the wood and three or four 

 screens made to slide into their places, and these can be cleaned 

 in a twinkling and put back again when necessary. 



Although, in many places artificial hatching beds may be, 

 and are, most successfully worked without filtering the water, yet 

 there are many streams which bring down such an amount of 

 earthy matter every time there is a spate, that filtration becomes 

 absolutely necessary. When such is found to be the case a very 

 good plan is to dig out a settling pond, or if necessary two or 

 three of them, on the water supply. Do not on any account 

 attempt to make one on the stream itself. Draw the water from 

 the stream and pass it through a hole sunk in the ground, say 

 at least six feet square, and three feet in depth. If twelve 

 feet square and four or five feet deep, so much the better. It does 

 not matter whether the sides are rectangular. Let them be so if 

 practicable, but should the land not allow of it, it is not worth 

 troubling much about. The great thing is to pass the water 

 through a large hole or pool, in which it will have a chance 

 of being fairly tranquil. The result will be that the bulk of the 

 sediment brought down during a spate, will be left at the bottom 

 of this pool, and the water for supplying the hatching bed should 

 be drawn off at or just below the surface. If one pool be found 

 insufficient, have a couple of them ; they are easily made and at a 

 very trifling cost. Where stone is available the sides are better 

 built up of loose stonework, as the action of frost is not so much 

 felt, as is the case where they are simply dug out and left. 



To make the thing more perfect still, should it be found 



