Hatching with Incubators 135 



ing after the incubation try to get the chicks out 

 on time. This means steady heat. Trained men 

 say that a chick hatched the twentieth day is 

 worth two bom on the twenty-second. 



Moisture in Incubation. — The amount of mois- 

 ture in the air during incubation has an important 

 effect in the result, and a generous amount is 

 needed for a successful hatch. The average 

 fresh egg contains almost seventy per cent water, 

 and a laige part of this is necessary to the growth 

 of the chick. If the air about the eggs is too dry, 

 this" water evaporates through the shell so fast 

 that the embryo suffers. 



There are no easy methods of determining the 

 exact amount of humidity in the egg chamber, 

 but fortunately there is no necessity for exact 

 calculations on this point. The operator need not 

 worry so long as he uses a cellar, or a room not 

 too dry, and runs the machine according to the 

 maker's regulations. Reports of experiment sta- 

 tions tend to prove that the instruments usually 

 sold to show relative humidity about the egg tray, 

 are not accurate, not valuable, and really not 

 needed. 



The nose can usually tell at once whether the 



