Fish-Hatching in a Current of Water. 1 1 1 



admit light, which, although not needed during 

 the process of hatching, is essential to the 

 health of the young fish when hatched. 



The boxes being all in their places, and the 

 water running well from one to the other 

 throughout, and the screens fitted in their 

 slides, the gravel may be put in them. It 

 should be well washed, and, if river gravel, 

 it should be boiled, so as to kill any eggs of 

 water insects that it may contain. It must 

 first be carefully screened to the right size, 

 one screen taking out the larger gravel, and 

 another the sand and fine gravel. When it 

 is ready, it must be spread smoothly and 

 evenly over the bottom, to such a depth as 

 will leave from half an inch to an inch of 

 water over it, according to the supply. The 

 current should be brisk, but not strong 

 enough to carry away the eggs, as rest is 

 essential to the development of the embryo. 

 When the gravel has been put in the boxes, 

 they are then ready to receive the ova. If 

 these have been packed in snow or ice, they 

 should not be at once placed in water that 

 may be much warmer, but the water should 

 be brought down to, say, 40 deg. by the use of 



