damper. Open it. In what direction do the hot gases pass out when the oven
damper is open? What part of the range is heated when the oven damper is
open?

_An open damper permits a direct draft to pass through the range_
(see Figure 10).

Close the oven damper. Trace the direction of the hot gases when the
damper is closed. What parts of the range are heated when the oven damper
is closed?

_A closed oven damper permits an indirect draft to pass through the
range_ (see Figure 11).

How should the front, oven, check, and chimney dampers be arranged when
the fire is kindled?

PRODUCTS OF COMBUSTION.--What is found deposited on the inside of the
stovepipe of a coal range? To what is the upper end of the stovepipe
joined? What does one often see coming from the top of a chimney?

[Illustration: FIGURE 10.--COAL RANGE SHOWING COURSE OF DIRECT DRAFT.]

In the previous lesson it was found that when a material burned, it united
with oxygen. It is a matter of common observation that when all solid
fuels--coal, wood, paper--burn, they decrease in size, and that fuel gas
is consumed. Apparently only a few ashes remain when solid fuels have
been burned, and only a disagreeable odor remains when gas has been
burned. Yet soot is deposited in the stovepipe and smoke issues from the
chimney. Both solid and gaseous materials, such as ashes, soot, and smoke,