13 
siderable humidity to cause them to hatch. Such matters must be 
largely regulated by the experience of the individual raiser. 
The desired conditions can be better regulated in specially constructed 
incubators than in an openroom. A simple form of incubator is shown 
in Fig. 5. It consists of a tin cylinder with a perforated shelf and a 
a 
uy 
Fic. 5.—Incubator made of tin-ware (after Roman). 
movable cover. Under the shelf is placed upon a tripod a small vessel 
of water, beneath which burns a small night-lamp. This apparatus may 
be made about eight times the size of the drawing. A similar and sim- 
ple form of basket-ware incubator is shown in Fig. 6. This possesses 
Fic. 6.—Incubator made of basket-ware (after Roman). 
the advantage of being permeable to the air and of thus insuring a more 
complete ventilation for the eggs. Many modifications of these designs 
will suggest themselves to individuals; amongst others the surround- 
ing of the cylinder of the incubator first described with a jacket, in 
which hot water may be placed, by means of which the temperature of 
the interior may be regulated with a considerable degree of nicety. 
