120 FISH CULTUBE 



painted. I have heard fish-culturists complain 

 that tar is injurious and that it had killed their 

 fish; but I am satisfied from my own experi- 

 ence, as well as that of most fish-culturists, that 

 this is a mistake; indeed tar may be esteemed 

 beneficial, since it is a germ destroyer. Black 

 asphaltum paint, however, may be safely used, 

 if tar is not easily available. 



Surprise may be expressed by some persons 

 that I have not advocated the use of heavier 

 lumber than one inch for the construction of 

 hatching-troughs of the type described. It 

 has not been many years since it was claimed 

 to be unsafe to use lumber less than two inches 

 thick on account of jarring, but I have found 

 no ill results following the use of one-inch lum- 

 ber, and I have superintended the hatching and 

 distributing annually of from 7,000,000 to 

 13,000,000 trout; furthermore the average hatch 

 from the eggs taken from the brood-fish in the 

 hatcheries has been regularly over 90 per cent. 



The ends of the trough may be flush, there 

 being no necessity for dovetailing. The 

 troughs can be made perfectly water-tight by 

 making a scratch the whole length of the bot- 



