Incubation 



1845 



The regulator bar. — The regulator bar should be placed so that the pivot 

 casting rests squarely on the base casting, as indicated in Fig. 55, with the 

 disk, when it is attached, hanging directly over the exhaust in the top of the 

 heater. The disk should cover the exhaust hole evenly, entirely closing it 

 when it is down; otherwise some heat will be lost and the effectiveness of 

 the action of the thermostat will be lessened. 



The connecting rod. — The connecting rod should be passed down through 

 the connecting tube and into the hole in the top of the thermostat. In 

 some incubators the connecting rod passes through the thermostat and is 

 fastened by screwing a nut to the bottom of the rod ; in others, the rod 

 merely screws into the thermostat; either way is satisfactory. 



The counterpoise rod and weight. — The counterpoise weight is usually 

 adjusted on the rod 

 before the incubator 

 leaves the factory, and 

 should not be moved 

 unless it has been 

 pushed back so that 

 it overbalances the 

 bar, thus preventing 

 an easy action of the 

 bar when it is lightly 

 pressed down from 

 the wire connecting- 

 rod. In the latter 

 case, the weight may 

 be moved until the bar works freely when the thumbscrew on the con- 

 necting rod is loose above the bar. The counterpoise weight should 

 never be moved in order to regulate the heat. 



Fig. 58. — Parts of heater, i, Screen; 2, fume exit; j (below 

 2), fresh-air entrance; 4 (below j), metal cap; 5, asbestos 

 jacket 



The heater 

 The heater is attached to the incubator when it comes from the factory, 

 and no changes should be made unless it has been damaged. The heater 

 should be gas-tight, fireproof, and strong, and it should be constructed of a 

 material that will hold all the heat given off by the lamp, thereby making it 

 necessary to run only an ordinary flame with an economical use of oil. The 

 heater should be cleaned very carefully and thoroughly, especially if the lamp 

 has smoked. A wire with a cloth fastened to one end should be used, and the 

 cleaning should be done by inserting the cloth into the opening and twisting 

 it until all the soot is removed. The isinglass should be cleaned thoroughly 

 after the soot has been removed ; otherwise it will be difficult to see the flame. 

 An oily cloth should never be used in cleaning incubator heaters. In case 



