"The important secret of compounding and directing this
artificial flame was imparted [in the later part of the
seventh century to the Greeks, or Byzantines, at
Constantinople] by Callinicus, a native of Heliopolis, in
Syria, who deserted from the service of the caliph to that of
the emperor. The skill of a chemist and engineer was
equivalent to the succour of fleets and armies; and this
discovery or improvement of the military art was fortunately
reserved for the distressful period when the degenerate Romans
of the East were incapable of contending with the warlike
enthusiasm and youthful vigour of the Saracens. The historian
who presumes to analyze this extraordinary composition should
suspect his own ignorance and that of his Byzantine guides, so
prone to the marvellous, so careless, and, in this instance,
so jealous of the truth. From their obscure, and perhaps
fallacious hints, it should seem that the principal ingredient
of the Greek fire was the naphtha, or liquid bitumen, a light,
tenacious, and inflammable oil, which springs from the earth.
… The naphtha was mingled, I know not by what methods or in
what proportions, with sulphur and with the pitch that is
extracted from evergreen firs. From this mixture, which
produced a thick smoke and a loud explosion, proceeded a
fierce and obstinate flame … ; instead of being extinguished
it was nourished and quickened by the element of water; and
sand, urine, or vinegar were the only remedies that could damp
the fury of this powerful agent. … It was either poured from
the ramparts [of a besieged town] in large boilers, or
launched in red-hot balls of stone and iron, or darted in
arrows and javelins, twisted round with flax and tow, which
had deeply imbibed the inflammable oil; sometimes it was
deposited in fire-ships … and was most commonly blown
through long tubes of copper, which were planted on the prow
of a galley, and fancifully shaped into the mouths of savage
monsters, that seemed to vomit a stream of liquid and
consuming fire. This important art was preserved at
Constantinople, as the palladium of the state. … The secret
was confined, above 400 years, to the Romans of the East. …
It was at length either discovered or stolen by the
Mahometans; and, in the holy wars of Syria and Egypt, they
retorted an invention, contrived against themselves, on the
heads of the Christians. … The use of the Greek, or, as it
might now be called, the Saracen fire, was continued to the
middle of the fourteenth century."
_E. Gibbon,
Decline and Fall of the Roman Empire,
chapter 52._