CARE OF THE EGGS. 297 



with half-inch holes bored in the bottom, Cyphers gives 

 the following as the number of holes required for each 

 hundred eggs to keep the air of the egg chamber reason- 

 ably pure : 



" For the first ten days of incubation, under an outer atmospheric 

 temperature of from 50 to 70, three holes ; under an atmospheric tem- 

 perature of from 30 to 50, two holes. From the tenth day to exclu- 

 sion, under an atmospheric temperature of from 55 to 70, six holes ; 

 under an atmospheric temperature of from 40 to 55, five holes; 

 and under an atmospheric temperature below 40, four holes. The 

 number of holes given above is for a chamber which is opened morn- 

 ing and night. There is no way of shifting the position of the eggs or 

 trays without opening the chamber, and unless their position is 

 changed so as to equalize the heat received, it is impossible to suc- 

 cessfully incubate a large number of eggs in one apartment.'* 



