But there is no need of documentary evidence to attest the power of the Ottoman artillery of this period; cannon built on the above model have guarded the Dardanelles for centuries, and, what is more, have proved sufficiently effective in modern engagements. In 1807 Sir John Duckworth’s squadron was struck repeatedly by stones of enormous weight, discharged from these cannon in an attempt to prevent its passage. And it is known that some of them were made shortly after the taking of Constantinople. These cannon, says General Lefroy, were cast on their faces, “the dead-head being left at the breech-end and hewn off with axes, probably while the metal was hot.” In one of them brought home to England “the axe marks are plain; similar marks may be observed on other early guns which have the breech cut off square.” The similarity of design between this Turkish gun and the Flemish bombards is too close to be accidental; their construction is of peculiar interest and has the main features in common. “The external form of the gun is a cylinder, the muzzle being as large as the breech; but either half is relieved by a boldly projecting moulding at each end, which is divided transversely by sixteen cross-bars into as many recesses: thus serving to give a purchase to the levers used in screwing the two parts together.” How the screw threads were cut is not known, but “we can suppose that moulding pieces were first cut in wood and nicely fitted and then applied to the clay moulds.” The charge of powder used with this type of piece was as much as a hundredweight. In spite of the weakness of the squib-like powder its physical and moral effect was undoubtedly important. “Thus inconceivable and incredible,” writes the chronicler of 1467, “is the nature of this machine. The ancient princes and generals did not possess and had no knowledge of such a thing.... It is a new invention of the Germans or of the Kelts made about one hundred and fifty years ago, or a little more. It is an ingenious and happy discovery, especially the powder, which is a composition made of saltpetre, of sulphur, of charcoals, and of herbs, from the which composition is generated a dry hot gas....” [Illustration: TURKISH BRONZE CANNON From Lloyd and Hadcock’s _Artillery_] The founding of these enormous cannon on the field of action is in itself a tribute to the energy and resourcefulness of the nation who have been described as being, at that time, the finest engineers in the world. Of the effectiveness of the Ottoman artillery there is evidence in the results achieved. Constantinople fell to the giant bombards. And in the early part of the following century Rhodes, the last outpost of the Knights, fell to the same great power. The invention of the Christians[46] was, in fact, the weapon which gave supremacy to the Infidel in the eastern part of Europe.