The first arms and machines employing gunpowder as the propelling agency, came into use in the fourteenth century. Prior to this time there were machines and instruments which threw stones and catapults and large arrows by means of the reaction of a tightly twisted rope made up of hemp, catgut or hair. Slings were also much employed for hurling missiles. The first cannons were used by the English against the Scots in 1327. They were short and thick and wide in the bore and resembled bowls or mortars; in fact this name is still applied to this kind of ordnance. By the end of the fifteenth century a great advancement was shown in the make of these implements of warfare. Bronze and brass as materials came into general use and cannon were turned out with twenty to twenty-five inch bore weighing twenty tons and capable of hurling to a considerable distance projectiles weighing from two hundred pounds to one thousand pounds with powder as the propelling force. In a short time these large guns were mounted and carriages were introduced to facilitate transportation with troops. Meantime stone projectiles were replaced by cast iron shot, which, owing to its greater density, necessitated a reduction in calibre, that is a narrowing of the bore, consequently lighter and smaller guns came into the field, but with a greater propelling force. When the cast iron balls first came into use as projectiles, they weighed about twelve pounds, hence the cannons shooting them were known as twelve-pounders. It was soon found, however, that twelve pounds was too great a weight for long distances, so a reduction took place until the missiles were cut down to four pounds and the cannon discharging these, four pounders as they were called, weighed about one-quarter of a ton. They were very effective and handy for light field work. The eighteenth century witnessed rapid progress in gun and ammunition manufacture. "Grape" and "canister" were introduced and the names still cling to the present day. Grape consisted of a number of tarred lead balls, held together in a net. Canister consisted of a number of small shot in a tin can, the shots being dispersed by the breaking of the can on discharge. Grape now consists of cast iron balls arranged in three tiers by means of circular plates, the whole secured by a pin which passes through the centre. The number of shot in each tier varies from three to five. Grape is very destructive up to three hundred yards and effective up to six hundred yards. Canister shot as we know it at present, is made up of a number of iron balls, placed in a tin cylinder with a wooden bottom, the size of the piece of ordnance for which it is intended.