Various circumstances tended to check the progress of fire-arms, and the improvement of artillery, for a long period after the invention of gunpowder. Custom made most people prefer the ancient engines of war. The construction of artillery was very awkward and imperfect; and the bad quality and manufacture of gunpowder, so that it could produce but little effect; and there was a general aversion to the newly invented arms, as calculated to extinguish military bravery, and as being contrary to humanity; but above all, the knights (whose science was rendered completely useless by the introduction of fire-arms) opposed, with all their might, this invention, to which may be added the great cost and difficulty of procuring gunpowder. ~Rockets in India.~ It is known that iron rockets have been used in India as military weapons, time out of mind. (See plate 4, fig. 3.) GREEK FIRE. ~Discovered by Callinicus. A. D., 617.~ The Greek Fire has been highly extolled for its wonderful effects, but it owed much of its effect to the terrors and imagination of the beholders. It is said by the Oriental Greeks, to have been discovered by Callinicus, an architect of Heliopolis or Balbeck, in the reign of the Emperor Constantine Pogonatus, who, it is said, forbad the art of making it to be communicated to foreigners, but it was at length known, and in common use, among the nations confederated with the Byzantines. ~Known in China, 917.~ It is also said to have been known in China in 917, being 300 years after Constantine Pogonatus, under the name of “The oil of the cruelfire,” and was carried thither by the Kitan Tartars, who had it from the King of Ou. ~Wild fire from the Saracens.~ It was thrown by machines, by the hand, and by cross bows, fastened to the heads of arrows. The Crusaders obtained a knowledge of a sort of wild fire from the Saracens, which could only be extinguished by dust or vinegar. It was composed of the gum of resinous trees, reduced to powder with sulphur, to which was added naptha, and other bitumens, and probably nitre. ~Wild fire in the Holy Wars.~ ~Geoffrey de Vinesauf’s account.~ ~Father Daniel’s account.~ ~Used at the siege of Dieppe.~ It is much spoken of in all the Holy Wars, as being frequently employed by the Saracens against the Christians. Procopius, in his history of the Goths, calls it Media’s oil, considering it an infernal composition prepared by that sorceress. Geoffrey de Vinesauf, who accompanied Richard I. to the Crusades, says that it could not be extinguished by water, but that sand thrown upon it abated its virulence, and vinegar poured upon it put it out. Father Daniel says this wild fire was not only used in sieges, but even in battles, and that Philip Augustus, King of France, having found a quantity of it ready prepared at Acre, brought it with him to France, and used it at the siege of Dieppe, for burning the English vessels in that harbour.