THE CALIFORNIAISr SALMON. 
83 
with the salmon, bears the temperature of our streams 
admirably, and the ova hatch out successfully at a tem- 
perature of 55 deg, to 60 deg. without any great loss. 
The best place to select as a site for the artificial hatching 
of these fish, is undoubtedly at a spring, where the tempera- 
ture of the water is little influenced by atmospheric 
changes. The water should be free from mineral taint, 
and of considerable volume, so as to ensure a good 
current. The ova are generally spawned at the time when 
the temperature of the streams is at its minimum, and 
it is therefore very desirable to have the command of 
both spring and brook water, so that either or both can 
be used if desired. When salmon ova have been brought 
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. in 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,' or about the 20th November, and although 
the summer has then set in, the water of the streams has 
not yet been greatly raised in temperature, and the hatch- 
ing out going on with great rapidity, the young fish 
have made very considerable growth, before the great heat 
of summer sets in. From this fish having different habits, and 
spawning about the end of summer, the young fry are better 
able to resist a high temperature, which, if injurious to the 
ova in hatching, ^is certainly, up to a certain point, favour- 
able to the growth of the young salmon. 
It is a well-ascertained fact, that trout in cold streams 
