53 
The Illustrated Book of Poultry. 
the source of heat by a wire, chain, or thread, M, in any desired manner. In the incubators we 
saw at Messrs. Kent and Co.’s it is so connected in two ways, according as gas or oil is employed. • 
hor oil, two or three wicks are arranged, one centrally and the others at the circumference/sof. /. 
a revolving tray, nicely balanced upon a central pivot. The central wick, of course, remains 
stationary, and supplies the minimum, amount of heat needed under the boiler; but „.the wire or 
thread, M, being connected with the tray, causes one or more of the other wicks to revolve so as to 
come under the boiler as the heat decreases. The bottom of the boiler forms an inclined plane, 
so that, as the supplementary wicks revolve with the tray, they approach nearer to, or recede 
farther from, the bottom of the boiler, and so impart more or less heat. For gas, the arrangement 
is connected directly with a tap which governs the supply. 
The incubator itself is arranged as follows : — The eggs are laid in oval holes in a plate, N. 
Fig. 36. 
A cold-water tank underneath supplies some moisture ; and more is given by wetting portions of 
cotton-wool, which are placed in small holders, O, up the centre of the egg-plate. Air is admitted 
pretty freely under the egg-plate, which thus keeps the under-surface cooler than the top, 
escaping by openings above. The rows of eggs thus placed are ranged immediately under arches 
in the heating-tank P, connected by a pipe, Q, with the boiler. The eggs, as soon as chipped, 
are intended to be hatched out in the receptacle or hatching-box R, on top of the heating- 
cistern, which is supplied with damped sawdust and cotton-wool to keep up the necessary 
moisture. The boiler is in two parts : the part heated directly by the flame, and another 
part— or jacket — which is not in contact with the flame, but heated by the water in the 
first. The jacket keeps the temperature much more uniform, and is the part connected with the 
heating-tank ; but the column of water, A, in the regulator is connected with that part of the 
boiler which is in contact with the flame. The jacket also supplies heat to “mothers” for the 
chicks on each side. 
There were two undesirable points about this incubator. The first was, that the sensitive 
regulator was partly thrown away, by being connected, not with the hot air in the egg-chamber, 
but with the water in the heating-tank— a very different thing in practice. By packing well with 
sawdust, however, the effects of this were in great measure avoided ; and correspondents in widely 
different quarters, who had mastered the working of this machine, reported uncommonly well 
of it, showing the real importance of a steady temperature. A second and more tangible fault 
