Mr. Hals teds Ixcubator. 



57 



D is the egg-drawer or nest, above which is the square tank which supplies the heat, a space of two 

 inches being left between the tank and top of the drawer to allow room for the regulator. The 

 boiler B is connected with the heating-tank by the supply and return pipes F and R. 



Fig- 35- 



Figs. 36 and 37 show the construction and connections of the boiler and heating-tank. The 

 lower part of the lamp chimney is one half of a sphere, resembling the lower part of a common 

 bulged chimney. The top edge of this semi-globe or saucer, which is made of tin, fits against 

 the bottom of the conical flue S which passes through the middle of the boiler and completes 

 the chimney, opening into the atmosphere. The space between this flue and the outer case of the 

 boiler is divided by a cylindrical partition or diaphragm, which reaches from the top to nearly the 



Fig. 36. 



Fig. 37- 



bottom ; the supply pipe, F, being conducted from the inner and the return pipe, R, to the outer portion 

 of the boiler. The effect of this is to keep up a constant and rapid circulation of the water in the 

 direction of the arrows (Fig. 36.) The water from the tank passes first into the outer portion, E, 

 thence under the partition into the inner port;- in, I, where it is rapidly heated and passes off again 

 by the tube F into the tank, T (Fig. i']). The boiler is also furnished with a stop-cock to draw off 

 the water when required. 



Fig. 38 represents the boiler and tank in plan, for the sake of showing the arrangements, 

 which, though simple, are of a very important character. The boiler, B, and flues, F and R, are 

 8 



