In the East engines were employed not only to extinguish but to produce fires. The Greek fire, invented by Callinicus, an architect of Heliopolis, a city afterwards named Balbec, in the year 678, the use of which was continued in the East till 1291[594], and which was certainly liquid[595], was employed in many different ways; but chiefly on board ship, being thrown from large fire-engines on the ships of the enemy. Sometimes this fire was kindled in particular vessels, which might be called fire-ships, and which were introduced among a hostile fleet; sometimes it was put into jars and other vessels, which were thrown at the enemy by means of projectile machines[596], and sometimes it was squirted by the soldiers from hand-engines; or, as appears, blown through pipes. But the machines with which this fire was discharged from the fore-part of ships, could not have been either hand-engines or such blow-pipes. They were constructed of copper and iron, and the extremity of them sometimes resembled the open mouth and jaws of a lion or other animal; they were painted and even gilded, and it appears that they were capable of projecting the fire to a great distance[597]. These machines by ancient writers are expressly called spouting-engines. John Cameniata, speaking of the siege of his native city, Thessalonica, which was taken by the Saracens in the year 904, says that the enemy threw fire into the wooden works of the besieged, which was blown into them by means of tubes, and thrown from other vessels[598]. This passage, which I do not find quoted in any of the works that treat on the Greek fire, proves that the Greeks in the beginning of the tenth century were no longer the only people acquainted with the art of preparing this fire, the precursor of our gunpowder. The emperor Leo, who about the same period wrote his art of war, recommends such engines, with a metal covering, to be constructed in the fore-part of ships[599], and he twice afterwards mentions engines for throwing out Greek fire[600]. In the East one may easily have conceived the idea of loading some kind of pump with the Greek fire; as the use of a forcing-pump for extinguishing fires was long known there before the invention of Callinicus.