By guns, only muskets, rifles, and fowling-pieces are here meant, since the manufacture of cannons, to which the term guns is now commonly applied, is an entirely different business to that of making what are called “small arms;” the latter including, in fact, swords, pistols, bayonets, muskets, rifles, and some other implements of war. There are so many varieties of fire arms, and they are sold at prices varying so greatly, that it would be almost impossible to give any detailed description of each kind of piece. The finely-finished rifle or sporting gun, fitted with the last improvements, breech-loading or otherwise, and finished with marvellous perfection and accuracy, is worth four times as many pounds as the common muskets, made for exportation to Africa for the use of the natives, are worth shillings. We may, therefore, describe some of the ordinary processes of the gunmaker’s trade, and the various improvements will then be better understood when the reader has an opportunity of seeing finished guns, in which such improvements may be pointed out to him. The barrels of guns are either plain or twisted; twisted barrels are made of long and very narrow strips of iron, one of which, being moderately heated to increase pliancy, is wrapped spirally round a cylindrical mandril in such a way as to form a tube, which may be slipped off the mandril at pleasure. As the rods are not usually made of sufficient length for one to form a barrel, several are usually joined end to end, those which form the breech being thicker than those at the muzzle end. By heating and hammering these pieces are welded into a continuous and very strong and tough tube. Partially worn iron, called “scrap iron,” is best for these purposes. The twisted barrels which are known as “wire twist” are formed of narrow rods of iron and steel forged together, and then rolled out to the proper thinness. Damascus barrels are composed of similar metal, but the rods are twisted on their own centres until the fibres which they contain have from twelve to fourteen turns in an inch by which the rods are doubled in thickness and proportionately reduced in length. Two such rods are welded together side by side, their respective twists being reversed. There are many modes of making twisted barrels, but these are the most common. After being welded, the barrels are carefully examined, and, if needful, straightened by a few blows of the hammer. They are then bored in a machine with an angular plug of tempered steel, which is caused to revolve rapidly within the barrel, while a stream of water is directed upon the outside to check the heat caused by the tremendous friction. The outside is brought to a smooth surface either by grinding on a large grindstone, or turning in a lathe. The breech end of the barrel is bored with a screw-thread, to receive the breech plug, which closes it at that end.