proof is
impossible, speculation is to a certain extent admissible as a link to
render isolated facts intelligible.

It may be well here if, before passing to the more immediate object of
this paper--viz. a sketch of the probable progress of pyrotechny--we
explain to those of our readers who are unacquainted with chemistry, the
philosophy of explosive combustibles.

Combustion is nothing else than rapid chemical union, taking place
between two dissimilar substances, which have what is called an affinity
for each other, _i.e._ a tendency to unite and form a new compound. When
a candle or lamp is burned, it is carbon and hydrogen, the principal
constituents of oil or fat, which combine with oxygen, one main
ingredient of the atmosphere. As it requires a certain temperature for
this union to take place, to prevent the cooling effect of mass, a wick
is used which can be readily heated, and where, as soon as chemical
action has once taken place, other portions of the oil or melted tallow
are absorbed, which ascend just as water through the pores of a sponge,
and supply the place of those burned. In this example, only a small
ignited surface is exposed to the influence of the oxygen: if, however,
this latter element could be obtained in a solid state, and mixed up
with the combustible, each particle throughout the whole mass would have
in contact with it a particle of oxygen; so that, if the whole were
raised to the necessary temperature for combustion, combustion would be
instantaneous--or if the temperature of a part were sufficiently
elevated, the combustion of this portion would communicate an intense
heat to the contiguous portions, and the whole would rapidly kindle as a
fuse does. In this case also, the access of the air being immaterial,
combustion might take place in a closed vessel, or even under water.

Nitre, or saltpetre, is one of a class of substances which contains a
large portion of oxygen in a combined and solid state; and, being mixed
with combustible matter such as charcoal, it causes rapid deflagration
when the temperature is raised. The whole class of pyrotechnic
compositions are reducible to this simple principle--they all consist of
combustible substances intimately mixed with substances containing
oxygen; or, to reduce the proposition to more general and simple terms,
they consist of two or more substances, having for each other a powerful
chemical affinity, and capable of rapidly uniting when the