126 The Hen at Work 



perature falls ten degrees, and a drop of thirty 

 degrees in the room would be a serious matter. 



For this reason the cellar is usually chosen for 

 such a location, unless it is poorly ventilated and 

 musty. A room where the heat is shut ofif, and 

 where the sun does not shine directly in, will also 

 give good results, imless the temperature varies 

 twenty degrees or more, or the room is very cold. 

 A room like a schoolroom, where the heat is 

 maintained to a certain extent all the time, would 

 serve. The sim should never shine directly on 

 the machine while hatching is in progress. 



Fresh air is necessary in the chamber for incu- 

 bation, but in no case must a draft play on the 

 incubator. A muslin curtain, tacked over the 

 window will admit air without much draft, but 

 even then care must be taken to protect the ma- 

 chine from currents of air. 



For the majority of those using a small incubator 

 the cellar will be convenient and available. It 

 should be thoroughly cleaned from all debris and 

 decaying matter, and arranged for ventilation, so 

 that it smells sweet and clean. 



Preparing for the Eggs. — It would be of no 

 value to attempt detailed instructions in a book 



