Fish-Hatching in a Current of Water. 109 



An American discovery, of the advantages 

 to be obtained by the use of charred wood for 

 hatching-boxes, has solved the problem most 

 satisfactorily, it having been found, after a 

 long and severe test, that no fungus appeared 

 on the carbonaceous surface. In one of the 

 hatching-boxes, by way of experiment, I 

 placed a bottom of ribbed glass, but found, 

 after trying this and also a charcoal bed, that 

 nothing suited so well as fine gravel of a dark 

 colour. If the gravel be of a light colour, the 

 dead eggs are less easily seen, from their 

 colour being also white. It is better that the 

 hatching-boxes should be tbree to four feet 

 above the ground, for convenience in picking 

 out the dead eggs, and for examination of the 

 fish and eggs from time to time. The stone 

 race being on the level of the ground neces- 

 sitates the kneeling posture in examining 

 them, which becomes very irksome and in- 

 convenient, as the young fish cannot be seen 

 so well, and dead ones may be left in the race, 

 thereby fouling the water, to the injury of the 

 live fish. 



The hatching-boxes were each secured at 

 the ends with fine screens of perforated tin. 



