To illustrate the operationB of a steam, generator, we give the
details of an appliance, which may be compared to the letter A
of the alpliahet, or the figure 1 of the numeralB, so simple



Fig. II, ia an eloTation of boiler, fig. 1? a vertical section
through itfl axis, and fig. 13 a horizontal section through the
farnace bars.
Fig. 11.
The type of steam generator here exhibited is what is knows
aa a vertical tubular boiler. The outside easing or shell is
cylindrical in shape, and is composed of iron or steel plates
riveted together. The top, which is likewise composed of the
same plates is slightly dome-shaped, except at the center, which
is away in order to receive the chimney b, which is round in
shape and formed of thin wrouglit iron plates. The interior
is shown in vertical section in fig. *^. It consists of a furnace
chamber, J, which contains the flre. The furnace is formed
like the shell of the boiler of wrought iron or steel plates by
flanging and riveting. The bottom is occupied by the grating,
on which rests the incandescent fuel. The grating consists of



UPRIGHT STEAM BOILERS,
a nnmber of caat-iron bare, d (fig. 12), end Bhown in plan in fig.
