TIME REQUIRED FOR DEVELOPMENT. 101 



the young fry soon begin to pine if the ther- 

 mometer marks many degrees over 55. " r 



The proper temperature of the water both 

 in and out of doors ought to range from 40 

 to 45. Mr. Bonder's observations tell him 

 that at this temperature it requires thirty- 

 five days for the eyes to appear (i. e. that the 

 fish is formed in the egg), and that tliey hatch 

 out fourteen days afterwards ; this same result 

 has been obtained by him for two seasons 

 following with very little variation, 



Again, he has observed that when the 

 temperature was 50 (in the spring of the 

 year) the eyes of the fish were visible in 

 twenty-six days, and that he hatched then 

 out in ten days afterwards. Lay it down 



* See report on experiments carried on by Mr. Youl and 

 myself at the end of the book. 



