THE INCUBATION OF THE EGG 



201 



now upon the market. Instead of opening a damper the 

 thermostat completes or breaks the circuit as more or less 

 heat is needed. 



Incubator Accessories. — ^The tools usually considered neces- 

 sary to successful incubation are a thermometer, a moisture 

 pan, and an egg tester. In. addition to this a hygrometer 

 and a turning device are sometimes used. 



FiQ. 101 



Showing moisture pan in use. (Courtesy of Prairie State Incubator 

 Company.) 



Thermometers. — ^The manufacturers of the better types of 

 incubators usually furnish fairly reliable thermometers with 

 them. Care should, however, be taken at the beginning of 

 every season's work to see that the thermometer is accurate. 

 Because it works perfectly one season is no criterion that it 

 will do so the next. It should be carefully compared with a 

 physician's clinical thermometer by moving the bulbs of 



