420 



POXTLTRY CULTURE 



(6) joined to a damper arm (fc) at the pivot casting (g). The 

 connecting rod passes through a connecting tube (d), which 

 supports the thermostat at its lower end by a casting (e) 



Fig. 156. — An incubator ready for use. Showing egg-try, nursery tray, 

 lamp, and thermoregulator. 



whiLb hes under the casting (/). The connecting rod must be 

 straight and pass through it without touching it. This makes 

 sure there is no friction for the thermostat to overcome. If the 



Fig. 157. — Various parts of a thermostat. (See body of text for description.) 



connecting rod becomes kinked it is better to obtain a new one. 

 When the thermostat expands it pulls down the connecting rod, 

 and a thumb-nut Qi) pulls on the pivot {g) which is situated 



