TYPES OF INCUBATORS 331 
and the size and style of the incubators. An economical cellar 
using many small machines in single tiers can be constructed for 
about $1.00 per dozen eggs, possibly less—even as low as fifty 
cents per dozen eggs. 
Location.—One of the best locations for an incubator building 
or cellar is on a side hill. Setting the building on the slope does 
away with one-half of the excavating, and at the same time per- 
mits an entrance on the same grade as the cellar floor. This fur- 
nishes a good outlet for air, and obviates the necessity of coming 
up and down stairs upon entering or leaving the cellar. 
The building should be near the dwelling or the keeper’s quar- 
ters, since it needs attention early in the morning and late at night. 
If within easy access of the brooder house, it will minimize labor 
when removing the 
chicks, and also lessen 
the danger of chilling 
them. 
Types of Incubators. 
—There are two general 
types of incubators, the 
distinction being based 
on the manner in which 
heat is supplied to the 
eggs. The problem in 
artificial incubation is Zz Lise UTE, ie 
to maintain a steady Fie. 157.—A common type of hot-air incubator. 
The incubator is given a ‘‘sun bath’’ before the next 
temperature of approx- hatch. 
imately 103° F. and care- 
fully to regulate the atmospheric moisture. In the various makes 
of incubators heat is imparted to the eggs in two ways,—directly by 
hot air from a'kerosene lamp (Fig. 157); and by air heated by com- 
ing into contact with a hot-water tank over a kerosene lamp. 
A brief comparison of these two methods may be made. With 
a hot-air machine an even temperature can be kept up. Since 
the air is heated directly by the lamp, any increase or reduction 
of the flame is immediately felt in the egg chamber; whereas with 
a hot-water machine the heat from the lamp must be imparted 
to the water, thence to the air in the incubator, and this consumes 
more time. With hot-air machines there is no copper or tin tank 
to be kept filled with water, hence no danger of this corroding 
and leaking in the middle of a hatch, the water soaking the machine 
cements nn cay mg mre 
