CANNON FOUNDING. Since sir W. Armstrong succeeded, by a process first brought under the notice of the British government in 1854, in making of malleable iron a field gun of far greater efficiency than any previously in use, cannon founding has in most European countries gradually ceased. This manufacture, which was formerly an impor tant one, is, however, still carried on in the United States, Sweden, and Russia, all three of which countries produce cast-iron of a very superior quality.
Cannon are cast in molds of loam or sand prepared with the help of a pattern, as described under FOUNDING. They are usually cast vertically with an extra mass of metal poured in at the top end of each mold to secure by its pressure greater solidity in its walls, as is often done in the case of a hydraulic cylinder. This superfluous portion is, of course, afterwards removed. Cannon are, or at least were, often cast solid with the same object, and afterwards bored, although it is by no means certain that such are generally sounder or of closer texture than those which are cast hollow. In either case the inner surface of the cannon is accurately finished with a boring tool to the required calibre, and the outer surface turned. Brass, or rather bronze cannon, were usually cast in loam by means of a clay model on which were often stuck ornamental figures in wax, these being melted out of the mold before casting.
In the United States, cast-iron guns are made by Rodman's process; that is, they are cast hollow on a core barrel which is filled with water. This is applied so as to cool the metal of the gun in layers, thus modifying the initial strain upon it, and producing the best result that can be obtained from cast-iron for ordnance purposes. Within the last few years guns as large in the bore as 20 in. have been cast by this method at Pittsburg, and one of the same size has been made by it in Russia. The latter weighs 44 tons, throws a spherical ball of 9 cwt., and took 84 months to finish. Its cost was not more than one fourth that of a built-up gun of steel for the same weight of projectile.
Many of the earlier pieces of ordnance, it is curious to observe, were made of hooped bars, hi which one can trace the germ of the process by which the Armstrong gun is mink% Indeed, it is doubtful if any modern plan of constructing large guns was not tried in olden times, as is seen by an examination of the different kinds of old cannon still preserved. These, however, had to be constructed without the aid of the steam-ham
mer and other appliances, which render such work comparatively easy nowadays, and were accordingly deficient in strength. Time earlier wrought-iron cannon were eventually superseded by thOsb unitlfrof cast-iron and bronze, but not entirely for some considerable time after the latter had been in use.
• was introduced about the commencement of the 14th c., appears to have been not only the most ancient form of cannon, but the first European fire-arm as well. From the beginning of the 15th c., cannon were cast iu bronze, and some of great size are stated to have been used at the siege of Constantinople in 1463. Probably hand cannon of cast-iron date as far back as bronze guns, and at any rate we know that large and excellent cannon were made of cast-iron in the early part of the 16th c., they having been used at Flodden, and England having even then acquired a reputation for Ibis kind of ordnance. See FIRE-ARMS. Cannon founding has therefore been practiced for nearly 500 years, and although the art is now to all appearance doomed to decay, no one can predict, in these days of metallurgical wonders, what further change improve ments in the manufacture of iron and steel may bring about as respects the making of large fire-arms. In order that the cast guns made on the old system may still be avail able for some purposes in modern warfare, col. Hay Campbell, sonic years ago, proposed a plan for lining bronze, and sir W. Palliser another for lining cast-iron cannon with a tube of wrought-iron. Some have been transformed on the Palliser system, which con sists in boring a certain thickness off the old gun, and forcing a coiled wrought-iron barrel into the interior, and are said to have given very remarkable results as regards endurance.
Certain peculiarities in the manufacture of special kinds of ordnance are noticed in the articles relating to them. See WAR-SERVICES.