REARING 151 



convenient for you to examine the eggs without much 

 stooping. 



The supply-pipe leading the water into the hatchery 

 should be protected against frost. In the case of a 

 spring this may be done by laying the pipes under- 

 ground. The receiving end of the pipe should be 

 covered with a cap of perforated zinc, to prevent the 

 possibility of any object alive or dead causing an 

 obstruction. 



It is necessary that the water which passes over 

 the eggs should be clear and, as far as possible, free 

 from sediment which is injurious to the eggs. Good 

 spring water requires very little filtration, but if you 

 are dependent on a brook or river for your supply, the 

 water will have to be made to pass through a filter 

 before it enters the hatching-boxes ; and if the stream 

 is very muddy you will have to adopt the further pre- 

 caution of allowing the water to clear itself in a settling- 

 tank. 



Before entering the hatching-boxes the water 

 should be exposed to the air. This is specially 

 desirable where your supply comes straight from a 

 covered spring, and the water first sees daylight in the 

 hatching-boxes. The water is therefore passed into 

 a long open trough or tank placed across the upper 

 end of the hatching-boxes, and as high above them as 



