They should be told that the mystery of the Greek fire had been revealed by an angel to the first and greatest of the Constantines, with a sacred injunction, that this gift of Heaven, this peculiar blessing of the Romans, should never be communicated to any foreign nation; that the prince and the subject were alike bound to religious silence under the temporal and spiritual penalties of treason and sacrilege; and that the impious attempt would provoke the sudden and supernatural vengeance of the God of the Christians. By these precautions, the secret was confined, above four hundred years, to the Romans of the East; and at the end of the eleventh century, the Pisans, to whom every sea and every art were familiar, suffered the effects, without understanding the composition, of the Greek fire. 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. A knight, who despised the swords and lances of the Saracens, relates, with heartfelt sincerity, his own fears, and those of his companions, at the sight and sound of the mischievous engine that discharged a torrent of the Greek fire, the _feu Gregeois_, as it is styled by the more early of the French writers. It came flying through the air, says Joinville, like a winged long-tailed dragon, about the thickness of a hogshead, with the report of thunder and the velocity of lightning; and the darkness of the night was dispelled by this deadly illumination. The use of the Greek, or, as it might now be called, of the Saracen fire, was continued to the middle of the fourteenth century, when the scientific or casual compound of nitre, sulphur, and charcoal, effected a new revolution in the art of war and the history of mankind. Chapter LII: More Conquests By The Arabs.--Part II.