being caught and run back to the generator,
while the ammonia in a nearly anhydrous state is condensed and
collected in the lower part of the vessel.

This process of fractional condensation is due to Rees Reece, and
forms an important feature in the modern absorption machine. Prior to
the introduction of this invention, the water evaporated in the
generator was condensed with the ammonia, and interfered very
seriously with the efficiency of the process by reducing the power of
the refrigerating agent by raising its boiling point. In the improved
form of apparatus, ammonia is obtained in a nearly anhydrous
condition, and in this state passes on to the refrigerator. In this
vessel, which is in communication with another vessel called the
absorber, containing cold water or very weak ammonia liquor,
evaporation takes place, owing to the readiness with which cold water
or weak liquor absorbs the ammonia, water at 59 deg. Fahr. absorbing 727
times its volume of ammonia vapor. The heat necessary to effect this
vaporization is abstracted from brine or other liquid, which is
circulated through the refrigerator by means of a pump. Owing to the
absorption of ammonia, the weak liquor in the absorber becomes
strengthened, and it is then pumped back into the generating vessel to
be again dealt with as above described.

The absorption apparatus, as applied for cooling purposes, consists of
a generator, which is a vessel of cast iron containing coils of iron
piping to which steam at any convenient pressure is supplied; an
analyzer, in which a portion of the water vapor is condensed, and from
which it flows back immediately into the generator; a rectifier and
condenser, in the upper portion of which a further condensation of
water vapor and a little ammonia takes place, the liquid thus formed
passing back by a pipe to the analyzer and thence to the generator,
while in the lower portion the ammonia vapor is condensed and
collected; and a refrigerator or cooler, into which the nearly
anhydrous liquid obtained in the condenser is admitted by a pipe and
regulating valve, and allowed to evaporate, the upper portion being in
communication with the absorber.

Through this vessel weak liquor, which has been deprived of its
ammonia in the generator, is continually circulated, after being first
cooled in an economizer by an opposite current of strong cold liquor
passing from the absorber to the generator, while, in addition, the
liquor in th