The bore is made of any rifle calibre for any small-arm ammunition, and is fitted with a safety-lock. For our own pieces we use the Lee-Metford cartridges. Four hundred shots per minute can be fired. The gun consists altogether of ninety-four pieces, but the working-pieces, _i.e._ those only which need be separated for cleaning, &c., when in the hands of the artilleryman, are less than twenty. It can be handled in action by one man, the operation resembling that of firing a pistol. The machine weighs 40 lbs., and for use by cavalry or infantry can be mounted on the _Dundonald Galloping Carriage_. The ammunition-box, containing 2000 rounds ready for use, carries the gun on its upper side, and is mounted on a strong steel axle. A pole with a slotted end is inserted into a revolving funnel on the bend of the shaft, the limbering-up being completed by an automatic bolt and plug. The gun-carriage itself is of steel, with hickory wheels and hickory and steel shafts, detachable at will. The simple harness suits any saddled cavalry horse, and the shafts work in sockets behind the rider’s legs. Its whole weight with full load of ammunition is under four hundredweight. HEAVY ORDNANCE. As with rifles and the smaller forms of artillery, so also with heavy ordnance, the changes and improvements within the last fifty years have been greater than those made during the course of all the previous centuries. These changes have affected alike not only the materials from which a weapon is manufactured, the relative size of calibre and length of bore, the fashion of mounting and firing, but also the form and weight of the projectile, the velocity with which it is thrown, and even the substances used in expelling it from the gun. Compare for a moment the old cast-iron muzzle-loaders, stubby of stature, which Wellington’s bronzed veterans served with round cannon balls, well packed in greasy clouts to make them fit tight, or with shell and grape shot, throughout the hard-fought day of Waterloo, from a distance which the chroniclers measure by _paces_, so near stood the opposing ranks to one another.