TEMPERATUKE OF WATER. 29 



eggs, took the tin boxes out of the saw-dust in which they 

 were packed, and set them in the water of their troughs, 

 with the idea perhaps of getting the eggs in the box to the 

 same temperature as the water in the troughs before un- 

 packing them. This will surely kill the eggs in a few 

 hours. Leave them in the original package until a few 

 hours before you are ready to place them in the troughs. 

 Then take out the tins and set them over or near the 

 troughs, which will reduce or raise the temperature enough. 

 Then empty the box into a tin pan full of water taken from 

 the trough, pick out as much moss as you can readily with 

 your lingers or nippers, and wash otf the nest in the man- 

 ner shown in directions for washing eggs in chapter YII. 



If the eggs have had decent treatment on the way, that 

 is not thrown about roughly or set near a red hot stove, 

 you should find very few dead eggs in the boxes, not more 

 than ten or twelve in one thousand, bliould the eggs be 

 found, on opening the box, run together in lumps mstead 

 of being evenly distributed, and turned to a dead white or 

 milky color, it shows rough usage on the way, and does not 

 necessarily show that the eggs were not impregnated or in 

 good order when sent. 



Temperature of Water and Time of Incubation. — The 

 length of time required to hatch out the eggs depends upon 

 the temperature of the water. A general rule sufficiently 

 accurate for all practical purposes is this : At fifty degrees 

 the eggs will hatch out in fifty days, each degree colder 

 takes five days longer, and each degree warmer five days 

 less. The difierence however increasing as the temperature 

 falls and diminishing as it rises. The best temperature 

 for hatching is between forty -five and fifty-three degrees. 

 We are inclined to believe that the fish hatched at a temper- 

 ature of about forty-five degrees and taking from seventy 

 to seventy-five days to hatch, are stronger and longer lived, 



