60 BROILERS AND ROASTERS. 



same eggs. This gives him more of an opportunity to 

 check his work with the incubator. He can compare the 

 ,air cells in the eggs in his incubator with those at the same 

 stage of incubation under the hens, and so judge better 

 about his ventilation and moisture. In case of failure or a 

 very poor hatch with a machine results from the eggs under 

 hens may indicate whether the trouble is in the eggs or in 

 operation. 



The ventilation of the cellar or other apartment in which 

 incubators are run must be such that there will be com- 

 paratively little odor from the lamps. A bad smelling 

 incubator room means impure air in the room, and that 

 means a lack of pure air and oxygen in the egg chambers. 

 Probably the best mode of ventilation is through windows 

 high up in the walls, having double sash, the outside one 

 being hinged at the top, and the inside one from the 

 bottom. The sash can then be opened as much or as little 

 .as is required. Their position with reference to each other 

 .sends the current of air entering the window upward and 

 away from the machines, so that the cool air introduced is 

 warmed before it reaches them. Another application of 

 the same idea in ventilation is sometimes made in the doors 

 which, as a rule, are double. A few large holes are bored 

 near the top or bottom, it makes no difference which, of 

 the outside door, and a corresponding number at the other 

 extremity of the inside door, thus providing for a slow 

 movement of air through these holes and the space between 

 the doors. Slides can be arranged to close a part or all of 

 the holes. With this provision in the door, and with one 

 or more windows as described above, proper ventilation is 

 a matter of judgment in the adjustment of the openings. 



