Af£ssj!s. Graves Incubator. 



55 



almost copied in many parts from the earlier model constructed by Mr. Halsted in the course of 

 his experiments ; but has been improved in several details and minor arrangements, and is without 

 doubt a good machine, though still capable of improvement. This incubator is shown in perspective 



Fig- ji- 



in Fig. 31, and a transverse section to show the interior arrangements more clearly is given in 

 Fig. 32. At the bottom is a cold-water tank, B, and above this is the hatching-chamber, C, heated 

 by the hot-water tank, D. Above this again is an air-chamber, E, for retaining or protecting the 

 heat acquired ; and on the top of all a drying-loft or nursery, F, where the newly-hatched chicks 

 are placed after birth until removal to the separate " mothers " provided for them. 



The mechanism of the incubator cannot be explained without constant reference to the 

 diagrams. The lamp G heats the boiler H, which latter communicates by tubes shown at 1 1 in the 

 transverse section with the hot-water tank D. J J in the perspective view are simply reservoirs which 



Fijr. 32 



supply oil to the lamps. Under and in contact with the heating-tank run two glass tubes filled with 

 alcohol, shown transversely at K K, and each of which at the outer end communicates by a bent tube, 

 I., with a cylinder, M, containing mercury, and which is furnished with a piston-float and rod, N. 



