lous, not to say insulting to the intelligence of 

 poultrymen, to assert that the heat from a hot 

 water tank is moist heat. 



We will go farther and say that the best hot 

 water incubators use moisture pans with from four 

 to ten times the area of evaporating surface used 

 in the modern hot air incubator. If the heat from 

 the hot water tank is moist, why use more water 

 in the egg chamber than is used in the hot air 

 machine? 



Now, let us see what logic there is in the asser- 

 tion that "hot air is necessarily foul air," when 

 applied to an incubator. 



The egg chamber of a modern hot air incubator 

 contains atmospheric air which is drawn into it 

 from the room in which the machine stands, 

 through ventilators having no connection whatever 

 with the heat reservoir, and the heat reservoir has 

 no opening whatever into the egg chamber. The 

 bottom of the heat reservoir is sheet metal and 

 forms the top or ceiling of the egg chamber. 



When the lamps are lighted the latent heat in 

 the oil is gradually evolved, and passes up through 

 the fire proof conductors into the reservoir. When 

 a sufficient quantity of this heat or caloric accu- 

 mulates in the reservoir being supplied faster 

 than it can pass out through the draft tubes of the 

 reservoir, which is open to the outer air above it, 

 it begins and continues to radiate from the metal 

 bottom of the reservoir and is diffused throughout 

 the egg chamber. Nothing passes through this 

 metal radiator but the heat ; no air, no gas, no 

 22 



