THE INCUBATION OF THE EGG 



195 



connecting rod and long damper arm, and diverting the heat 

 from the heating chamber. The heat is allowed to escape 

 until the egg chamber returns to the proper temperature, 

 when, by contracting, the thermostat causes the damper to 

 partially close and send more heat into the machine. With a 

 perfect regulating device an equilibrium may. be established 

 at any desired temperature, within certain limits, and that 

 temperature maintained in spite of rather sudden and marked 

 changes in outside temperature. 



Fig. 97 



Details of regulating device. A, nipple into which connecting rod fastens;- 

 B, bimetallic thermostat; C, casting joining connecting tube and thermostat; 

 D, connecting tube; E, support casting; F, base casting; G, pivot casting; 

 H, lower thumb nut; /, connecting rod; J, counterbalance weight; K, 

 damper arm; L, damper disk; M, knife-edge bearings; A'', upper thumb-nut; 

 0, locker nuts. (Courtesy of Robert Essex Incubator Company.) 



In detail the regulator consists (Fig. 97) of a thermostat 

 {B) which is joined to a damper arm {K) at the pivot casting 

 (G). The connecting rod passes through a connecting tube 

 ( B) which supports the thermostat at its lower end by means 

 of a casting (C), and is in turn supported at the upper end by 

 a casting {E) which lies under the casting {F). In setting 

 up or starting an incubator it should always be noted whether 

 the connecting rod is straight and passes through the con- 

 necting tube without touching. Where the connecting rod 

 touches it is impossible for the thermostat to overcome the 

 extra friction and give good service. A new connecting rod 



