[Illustration: FIG. 1.--PRODUCTION OF ILLUMINATING GAS.]
Burn a piece of paper of about the size of the hand upon a clean
porcelain plate, and this will serve to show the phenomena of
carbonization and the formation of empyreumatic products under the action
of heat. Under the burned paper there will be found a yellowish deposit
which sticks to the fingers, and which consists of oil of paper produced
by distillation. An idea of the production of illuminating gas through
the distillation of coal may be easily given by means a single clay pipe.
Upon filling the bowl of this with fragments of coal, closing the opening
with clay, and, after the latter is dry, placing the bowl in a coal fire
so that the stem shall project, gas will soon be observed issuing from,
the latter, and, when lighted, will give a very bright flame. If the pipe
seems to be a little too costly, recourse maybe had to a large piece of
wrapping paper rolled into the form of a cornucopia, and held in the left
hand by means of the pointed end. If, after an aperture has been made in
this near the point, the base be lighted, the heat developed by the flame
will produce a sort of distillation of the organic matter of the paper,
and the empyreumatic and gaseous products will rise in the cone, and make
their exit through the orifice, where they may be lighted with a match
(Fig. 1). It goes without saying that this experiment lasts but a few
seconds; but, as short as this period is, it is sufficient to give a
demonstration of the production of illuminating gas through the
distillation of organic matters. Care should be taken not to set anything
on fire while performing it, and it is well to operate over a pavement,
and far from any inflammable materials.