Though the probabilities of the use of gunpowder, as an explosive
compound, being suggested by accidents occurring in the manufacture of
combustible compounds, are thus shown to be very great, the actual step,
if step it were, still remains in obscurity. Most probably, like many
other inventions, the fact was observed again and again with different
degrees of accuracy and different resulting suggestions; until, at
length, growing intelligence seized on it, and increasing facility of
publication rendered its development more rapid and general. The actual
date of its general introduction or use in war is still uncertain.
Schwartz's discovery is stated by Kircher at 1354; but gunpowder is
stated to have been used at the siege of Stirling in 1339; in Denmark in
1340; in Spain in 1343; at Cressy in 1346; at the siege of Calais in
1347.

Without entering into the critical discussions which the vagueness of
the historical records of these periods might tempt, we can scarcely be
far wrong in setting down the general introduction of gunpowder during
the first half of the fourteenth century, although any attempt to
specify, from existing data, the exact date of its invention, would be
vain. With regard to its connexion with Greek fire, we may sum up by
stating, that during different periods, extending from the eighth to the
fourteenth century, combustible matters, in which saltpetre was one
ingredient, have been used; and that the term Greek fire has been, at
various times within this period, applied to them. Although it does not
necessarily follow that the Greek fire alluded to in the more recent
works was identical with the Greek fire of an earlier period, yet the
probability is strong that there was at least a striking analogy in
effect, or the name would not have been used. There is, moreover, some
internal evidence of community of origin in these various receipts, when
we find that in different parts of the world, in China, in Arabia, and
Greece, one general characteristic ingredient is present, viz., nitre;
when also the history and progress of chemistry have taught us that no
substance, other than nitre or a salt of nitric acid, has ever been, or
is now known, which would produce similar effects, (for the
comparatively recent discovery of the chlorates would produce effects of
detonation by friction or percussion, of which we find no records,)
there can, we think, be little doubt that Greek fire was of the same
chemical