TROUT-BREEDING IN WINTER 179 



you can get. Make a wire tripod stand for it of 

 about a foot in height. Into the hole at the 

 bottom of the pot insert a cork, through which a 

 glass pipe (easily procurable at your drug-store) of 

 about three inches long has been inserted. You 

 can bore the cork through with a red-hot iron, 

 and be careful that it is a good sound one ; also 

 be very sure that it fits the aperture exactly, so 

 that no water can escape except through the pipe. 

 The latter should be at least three-eighths of 

 an inch in diameter, inside measurement, or the 

 supply of water will be inadequate to the de- 

 mands of health in the fish. When the cork is 

 inserted, the glass pipe should be flush or even 

 with that part of it inside the flower-pot, and the 

 rest outside. On the outside length your India- 

 rubber piping will be attached. 



The making of the filter, from which we have 

 slightly digressed, is as follows : Having arranged 

 the cork and glass as I have directed, immediately 

 above the latter, inside the pot, a piece of well- 

 washed, fine sponge, not larger than a slice from 

 an orange of say half-inch thickness, should be 

 placed. Immediately on this a half-inch layer of 

 well-washed stones of not more than three-eighths 



