430 POULTRY CU1.TTJRE 



supply under all the sections and then across under the last 

 section to the left side of the machine, and is the common re- 

 turn pipe from the compartment radiators. This main supply- 

 can be piped in any direction, and there the sections can be set 

 in a continuous row, or to skip posts or a double row, and in 

 various other shapes. 



As stated before, in other type incubators there is but one 

 water-supply, which has two thermoregulators, the second 

 thermoregulator controlling the heat of the chamber by allow- 

 ing heated air to escape from a circular opening in the top of 

 the chamber and cool air to rush in to reduce the temperature 

 to the proper degree. 



In some makes of incubators the supply pipes, as well as the 

 return pipes, are on the inside of the compartments. 



All of the hot water, after leaving the heater, flows around 

 the bottom of the heater regulator, so that the regulator is 

 constantly affected by the temperature of the water, and it in 

 turn opens or closes the heater drafts, and thus automatically 

 controls the fire brought about by the expansion or contraction 

 of the mass of water contained in the pipes as a result of the 

 heat or cold. 



In those provided with a double system, as in Fig, 160, the 

 hot water rises, and the heating system is so arranged that were 

 there no compartment valves the water would be circulating 

 through each compartment radiator as well as the main supply. 

 It is necessary that each sitting of eggs have the exact degree 

 of heat required, according to the length of time incubation has 

 been in progress, and the compartment thermostats attend to 

 that for the operator. The thermoregulators admit the proper 

 amount of water to maintain the temperature needed in that 

 compartment. The hot water is always ready to pass the com- 

 partment valve and flow through the radiator and return 

 directly in the common return pipe to the heater to be reheated. 



It will be noted that the thermostat is directly above the 

 egg-trays. It is the desire at all times to know the temperature 

 at the top level of the eggs, and the best methods of handhng 

 the thermometer is by laying the thermometer bulb on the top 

 of a fertile egg. It is not desirable to lay the bulb on the top 

 of an infertile egg or one containing a dead embryo, as the 



