A SELF-SUPPORTING HOME 



connecting rod, on whose nicety of responsive- 

 ness to pressure depends the self-regulating 

 possibilities of the modern incubator. Unless 

 its passage through the several attachments 

 is uniformly even and free from friction, the 

 value of the thermostat is lost. This will be 

 obvious when the method of controlling heat 

 is understood. 



The thermostat is composed of a combina- 

 tion of such materials as aluminum and steel. 



THE REGULATOH-ARM 



Being extremely sensitive to heat, it expands 

 and contracts with every fluctuation of tem- 

 perature within the incubator. The regu- 

 lator-arm has a counterbalance ball at one 

 end and a metal disk at the other, and when 

 it rests on the pivot which is fixed at the top 

 of the machine, the disk should be suspended 

 directly over the lamp chimney. The con- 

 necting rod has two nuts at the top, and one 



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