ated near the bottom with arches for
the tuyeres or blast pipes, and also in front for the special blast
pipe and the tapping hole. The top of the furnace is closed with an
iron plate, provided with a circular opening, through which the hopper
enters the top of the furnace.

At the left in the larger engraving is seen an elevator, operated by a
steam engine, for conveying the garbage and refuse to a platform,
whence it is projected into the furnace by an inclined plane or chute.

Gas or smoke conductors convey the gas from the top of the furnace to
the furnace of the boiler and to the heating oven, where it is used in
heating air, which is conveyed through the iron pipes passing through
the heating oven into a wind box, from which it enters the furnace at
several points near the bottom by means of the tuyere pipes.

[Illustration: SECTION OF FURNACE.]

The consumption of the garbage is effected near the bottom of the
furnace, where the air is forced in, and is continued as long as the
blast is applied, and while burning at the base it is continually
sinking down at the top, so that it is necessary to keep filling all
the time. The odoriferous gases and the hot products of such
combustion are forced upward through the superimposed mass, and escape
to the fires of the boiler and heating oven, and, being largely
composed of carbonic oxide and the hydrocarbon gases distilled from
the animal and vegetable offal of the garbage, are thoroughly
consumed; and it is said that by this means not only are all the
offensive odors destroyed, but the heat generated is utilized for
making steam and heating the air used for blast.

The refuse in its descent through the high furnace is exposed to the
drying action of the hot gases of distillation and the hot products of
combustion, its temperature increasing in its descent the nearer it
approaches the tuyeres, and becomes completely desiccated and
combustible when it reaches the blast. The high heat in this way
obtained by the combustion of the organic portion melts all of the
inorganic portion, forming a vitreous slag or glass, which may be
allowed to run continuously, or by closing the tap may be allowed to
accumulate, and can be drawn off at intervals. If there is an adequate
supply of clay and sand in the refuse to combine with the ashes, the
slag will run hot and free. The combination of silex or alumina and an
alkali in proper portions always yields a fusible, easy-running
com