CHOOSING A LOCATION. 23 



cold water is absolutely necessary, must "be ap- 

 parent to all. For judging this, the only proper 

 time is during midsummer, when the supply is at 

 its minimum and the temperature at its maxi- 

 mum. Try the water with a good thermometer 

 (not one of those twenty-five cent abominations 

 with which the energy of peddlers have stocked 

 the country), and if the temperature is above 65, 

 though in the air it may be among the nineties, it 

 is unfit for fish culture. It is true that trout will 

 thrive even at a temperature some five degrees 

 higher, but it must be remembered that the water, 

 in passing through the ponds during the summer 

 season, has a most unpleasant habit of becoming 

 hotter and hotter, and while spring head is at 60 

 lowest pond may be some ten degrees higher. 

 Again, we have found from careful research that 

 the lower the temperature of the water to which 

 the spawn are subjected during incubation, the 

 more healthy the little fishes are likely to be ; we 

 say temperature of the water, for below 32 of 

 course ice is formed, which is in most cases fatal 

 to the vitality of the egg. The springs by which 

 the hatching-houses of our most successful estab- 

 lishments are supplied, range from 47 to 55. It 

 is true that by a low temperature the time of incu- 

 bation is lengthened, but this is a matter of little 

 importance ; again, with increased temperature 



