432 POULTRY CULTURE 



inside the egg chamber, and by pressing a button above the 

 door there is an illumination, making thermometer reading 

 easy. 



Ventilation of the compartments is made through holes in 

 the bottom. 



In egg development there is given off from the eggs carbon 

 dioxid. As carbon dioxid is heavier than air it settles to the 

 bottom, and with the ventilation in the bottom of the com- 

 partment the chamber should keep from having an excess of 

 this gas. 



The first principle in artificial incubation is a steady, even, 

 overhead heat, and no greater heat surrounding the eggs than 

 the hen gives. 



Cellar ventilation is essential, so that the air-supply outside 

 the machine is fresh. The eggs need the proper supply of 

 oxygen, and must have taken away the air that has become 

 polluted with CO2, as a result of the living processes of the 

 embryo inside the shell. 



Proper moisture should be in the air of the egg chamber, and 

 in order that the proper amount be ensured the chamber is 

 usually supplied with a water pan in which water is kept. The 

 proper amount of moisture prevents too rapid evaporation 

 from the egg during incubation. 



It is estimated that the minimum space of the incubator 

 cellar should be 2 cubic feet space for each egg-capacity 

 together with a circulation of fresh air. In incubator cellars 

 below the ground air shafts should be extended to the floor. 

 The windows should be on the north and not on the south or 

 west unless protected by shutters. Sun-rays finding their way 

 into the incubator cellar will modify the temperature too much 

 and make the variation between day and night more than can 

 be overcome by the thermoregulators of the incubators. The 

 room temperature should not vary more than 20° F. at the 

 most in twenty-four hours. 



Constant Temperature Essential. — For successful incubation 

 there must be a regular and constant temperature, with fresh 

 air and moisture at a definite rate. If it is an air circuit 

 machine and the pipe empties onto a diffusion diaphragm of 

 cheese cloth, this cloth must be kept brushed clean so as to 



