CANNON or _pieces of_ ORDNANCE, in the military art, imply machines having tubes of brass or iron. They are charged with powder and ball, or sometimes cartridges, grape and canister shot, &c. The length is distinguished by three parts; the first re-inforce, the second re-inforce, and the chace: the first re-inforce is ²⁄₇ths, and the second ¹⁄₇th and a half of the diameter of the shot. The inside hollow, wherein the powder and shot are lodged, is called the bore, &c. _History of_ CANNON or _pieces of_ ORDNANCE. They were originally made of iron bars soldered together and fortified with strong iron hoops; some of which are still to be seen, viz. one in the tower of London, two at Woolwich, one in the royal arsenal at Lisbon, they are numerous in all parts of Asia; and baron Tott describes them in Turkey. Others were made of thin sheets of iron rolled up together, and hooped; and on emergencies they were made of leather, with plates of iron or copper. These pieces were made in a rude and imperfect manner, like the first essays of many new inventions. Stone balls were thrown out of these cannon, and a small quantity of powder used on account of their weakness. These pieces have no ornaments, are placed on their carriages by rings, and are of cylindrical form. When or by whom they were made, is uncertain; however we read of _cannon_ being used as early as the 13th century, in a sea engagement between the king of Tunis and the Moorish king of Seville. The Venetians used _cannon_ at the siege of Claudia Jessa, now called Chioggia, in 1366, which were brought thither by two Germans, with some powder and leaden balls; as likewise in their wars with the Genoese in 1369. Edward III. of England made use of _cannon_ at the battle of Cressy in 1346, and at the siege of Calais in 1347. _Cannon_ were made use of by the Turks at the siege of Constantinople, then in possession of the Christians, in 1394, or in that of 1452, that threw a weight of 500lb. but they generally burst, either the first, second, or third shot. Louis XII. had one cast at Tours, of the same size, which threw a ball from the Bastille to Charenton. One of those famous _cannon_ was taken at the siege of Diu in 1546, by Don John de Castro, and is in the castle of St. Juiliao da Barra, 10 miles from Lisbon: its length is 20 feet 7 inches, diameter at the centre 6 feet 3 inches, and discharges a ball of 100lb. It has neither dolphins, rings, nor button, is of a curious kind of metal, and has a large Hindustanee inscription upon it, which says it was cast in 1400.