Fish- Hatching in a Current of Water. 103 



The best place to select as a site for the 

 artificial hatching of these fish is undoubtedly 

 at a spring, where the temperature of the 

 water is little influenced by atmospheric 

 changes. The water should be free from 

 mineral taint, and of considerable volume, so 

 as to insure a good current. The ova are 

 generally spawned at the time when the tem- 

 perature of the streams is at its minimum, and 

 it is therefore very desirable to have the com- 

 mand of both spring and brook water, so that 

 either or both can be used if desired. When 

 salmon ova are sent from England to 

 the Southern Hemisphere, they arrive before 

 the end of summer, or about the 20th of 

 March, when the water still retains a high 

 temperature, being the effect of the solar rays, 

 and, unless a spring with a low temperature be 

 at command, the water may be found up to 

 65 deg. on a hot day, being high enough to 

 make any chance of success very doubtful. 

 Even if ice be used, the difficulty of keeping 

 the temperature sufficiently low, both night 

 and day, for a lengthened period, is found to 

 hinder the success of the experiment. The 

 Californian salmon ova arrive at a better time, 



