INCUBATION OF THE EGG OF THE COMMON FOWL. 



369 



was the egg found to exceed the temperature given in the table 

 by more than one degree. In but few cases was it found to be a 

 degree lower. Although it cannot positively be stated that these 

 tested eggs would have hatched, the inference seems more than 

 probable, since in five other cases where hens were set on eggs 

 from the same flocks of fowls, the fertile eggs hatched with but 

 very few exceptions. These observations show that the proper 

 incubating temperature of the egg is about 100 for the first week ; 

 101 for the second, and 102 103 for the final week. 



Temperature of Artificially Incubated Eggs. The next problem 

 is to determine what temperature must be kept in the air chamber 

 of the incubator in order to obtain the above temperature of the 

 egg. A series of observations was made on the artificially in- 

 cubated egg. The temperature of the egg chamber was read 

 from a thermometer placed flat and on a level with the top of 

 the eggs, but not in contact with them. The temperatures of the 

 eggs were taken in precisely the same manner as in the preceding 

 experiment. 



The above record was made from an incubator which hatched 

 about 85 per cent, of the fertile eggs. The hatch, however, was 

 somewhat premature, since many of the eggs hatched on the 

 nineteenth day. It is thus evident that a temperature somewhat 

 too high had been carried. In view of the irregularities of the 

 incubator a second experiment was made. 



Egg. 



99.5 100.0 101.0 100.5 IOO -5 101.0 100.0 100.0 101.0 101.5 



