Gen. William P. Barry was the organizer of the A. of the union armies during the rebellion. The aggregate of field-guns was about 15,000, with 40,000 horses and 48,000 men. The number of m of position used in field-works or intreuched lines during that war was 1200, served by about 22,000 men. There arc at present in the regular army of the United States, o regiments of A., with 284 officers and 2321 enlisted men. The personal armament of an artilleryman of the mounted batteries, whether field or siege, is a pistol and saber for the sergeants, trumpeters, and drivers; and a saber only for cacti cannoneer. Those serving in the sea-coast fortifications have a rifle-musket and the full equipment of an infantry soldier. The material of a mounted battery of the U. S. field A. when on a war-footing is 6 guns, 6 caissons, 1 battery-wagon, 1 trav eling forge. and 112 horses; on a peace-footing it is 6 guns, 6 caissons, 80 horses. The ammunition of a field-battery for active service in war is 400 rounds per gun. The organization of a siege-battery in the U. S. service is 4 guns, 1 battery-wagon, 1 travel ing forge, and 60 horses. The ammunition for the siege-battery is 250 rounds per gun. The breech-loading principle was adopted in a clumsy way at the very outset of cannon construction. John Owen first cast brass cannon in England in 1535, and a year or two later they were manufactured in Scotland; hut no guns for firing hollow projectiles at long range by direct fire were known until col.Bomford, of the U. S. ordnance department, invented a cannon in 1812 called a " columbiad," which proved very success ful. Iron in some form is the sole metal in use for heavy artillery; cast iron is used for smooth-bore guns and for rifled guns in the United States. Palliser invented a gun with a steel interior tube, strengthened by an exterior iron; and his system became very popular in England; but the inventions of Sir 11 Armstrong, improved those of Fraser, proved far superior, and have been generally adopted. Russia, Germany,
and other nations have adopted the Krupp system with heavy forgings of steel ingots.
The defense of war-ships with iron armor has caused an increase in the size, weight, and calibers of sea-coast and naval cannon, and the whole method of gun-construction has been altered. Armstrong was the first in England to see the necessity of a change, and his method was improved by Whitworth, Fraser, Palliser, Blakely, and others. Francis Krupp of Essen, Prussia, is the inventor of a new method which proved so successful, that it has been introduced in Germany. Russia, Austria, Belgium, and Spain. The body of the gun is fabricated from a solid ingot of low steel worked under heavy steel hammers, and is strengthened by three or, more steel tubes, shrunk upon the central tube of the gun, the last ring, or tube inclosing the breech, being forged in one piece with the trunnions, without a weld. The rings have various lengths, and the gun is diminished in thickness towards the muzzle,: not by tapering, but by being turned by with concentric steps of diminished heights. Krupp makes all his projectiles and gun carriages of steel. In the United States, Rodman, Dahlgren, and Parrott have devoted themselves to the art of gun-construction. The Rodman gun is of cast iron; it is cast hollow and cooled from the inside, the exterior being in the mean time kept from rapid cooling by fires built around the gun in the casting-pit. The Dahlgren gun is of iron cast solid, and cooled from the exterior, very thick at the breech up to the trunnions, then diminishing in thickness to the muzzle. The Parrott gun, like the Rodman, is of cast iron, cast hollow, cooled from the inside, and strengthened about the chamber by an exterior tube of wrought-iron bars spirally coiled and shrunk on. It has been sug gested that a Rodman gun lined with wrought iron on Palliser's system would prove a highly effeetive.weapon. See BREECH-LOADING ARMS and NEEDLE-GUNS, ante.