Report on Miscellaneous Implements at Shrewsbury, 8fc. 27 
bottom of the water-tank converges upwards towards the centre, and is there 
pierced by an air shaft b carried up through the tank, and the packing and 
wooden casing, enclosing the tank. In the air chamber between the tank 
and the egg-drawer is fitted a patent thermostatic band of two metals of 
•unequal expansion q, on the same principle as is employed in a compensated 
watch. This band is acted upon by the heat passing over the eggs, and it 
•controls (through a lever connected with it by a rod c, passed down a small 
Fig. 10. — Sectional View of Patent Tltermostatic Incubator. 
A, valve acting upon B, the mouth of air 
-Shaft. 
c, rod connecting valve with the thermostatic 
band in the egg-drawer. 
D, the set screw for regulating the. tempera- 
'ture. 
E, the screen protecting the valve A and the 
1 lever. 
p, is the filling pipe. 
G, is the pipe down which the thermometer to 
■ test the water is dipped. 
H, the cowl of the chimney, now discarded as 
useless. 
H* is the circulating boiler in the centre of 
'the chimney. 
I, lamp screen and stand. 
K, the egg-tester. 
L are the air-holes. 
jf, the front of the drawer. 
N, the thermometer. 
o, the lamp. 
p, the wood slide to push lamp close up into 
the chimney. 
Q, the thermostatic band — when cold it follows 
the dotted line, when working it is pressed down 
at end attached to c by its own e.xpansion. 
B, R, circulating pipes. 
p, collar fitted at bottom of h. 
T, evaporating pan, covered by canvas, 
u, water tank. 
pipe inserted through the water tank) a valve a fitted upon the top of the 
air-shaft. The object is twofold: — first to ensure a regular temperature 
above the eggs, and secondly to produce a perfect system of ventilation in 
the egg-drawer. 
If the temperature in the egg-drawer rises, the metal band at once feels 
ithe effect, and draws down the rod attached to it, and thereby opens the 
valve, allowing more of the hottest air to escape, and preventing too great a 
rise of temperature. The reverse holds good of a falling temperature, and 
^the valve is no sooner shut than the heat begins to rise again. 
