Arms, weapons of defense. Just as the invention of powder made armor useless, so it changed the kinds of weapons used, which differentiates weapons into ancient and modern arms. Of ancient arms, the most common in the earliest wars were missiles to be used at long range. Thus, in the time of the Old Testament, the bow and the javelin were the favorite weapons of oriental races, while for close fighting merely straight daggers were used. Among the Greeks the chiefs used a long and heavy spear, which they threw as a missile, often ending their combats by a duel with short swords. The masses fought with a pike, in close column or in a phalanx, which afterward became so famous in the Macedonian phalanx with which Alexander the Great conquered the world. The pike was twenty-four feet long, held in the hand, and the men were so drawn up as to present a solid front of glittering spear-points. The Romans used a short massive javelin, six feet long, which they hurled at the enemy at a distance of ten or fifteen paces, and then closed on them with their short two-edged broadswords. They depended largely on the broadsword, and the lines were so drawn up that each man had room for full play with it in single combats, in which the training of the Romans almost always secured them the victory.

In the middle ages steel-clad cavalry were the main strength of the armies. Their arms were the lance, mace, battle-axe and the two-handed sword; but they relied mainly on the lance. This was a heavy weapon, eighteen feet in length, balanced by the weight of its butt end, which was often a foot in diameter at twenty inches from the extremity, and made to fit the arm of the champion as it was laid in rest. The infantry carried at this time the famous cloth-yard bow; the bills, like a heavy scythe blade, set erect on a four-foot shaft the leaden mallets and longs knives of the Anglo-Normans; the pikes and halberds of the Swiss; the crossbows of the Genoese; and the Scottish spear.

Modern arms begin with the battle of Pavia in 1525, when the matchlock was first used so as to be of any real service, though it was awkward and had to be used from a rest. It was gradually improved, and at the beginning of the 17th century the bayonet was added, which made it much more complete, as it gave the musketeer a means of defense at close quarters. The rifle was brought into prominence in the American Revolution and in the Revolution in France. Since that time improvement has been rapid, and the invention of the simple modern percussion lock, of the minie-rifle bullet, of revolving-chamber pistols and of breechloading of every kind has greatly increased the destructive character of warfare..

The greatest attention and most experimenting are given to field artillery. Old systems and types passed away with 1892, and in 1900 the weapon used in 1890 was not considered good enough. Machine-guns that load, fire and extract by machinery are the weapons of to-day. Some are operated by hand-power, others by the action of the powder-gases on a pistol or through the recoil of the barrel. The invention of smokeless powder, the application of electricity and the use of powerful explosives in shells have in recent years doubled the efficiency of arms. The speed at which they can be discharged had also increased greatly, the U. S. warship Georgia, five years younger than the Oregon, being able to fire nearly three and a half times faster. Smoke and fouling have been done away with. The size of weapons and their recoil from firing have been lessened. Pressure in the ammunition chamber has been diminished. Soldiers as well as gunners can aim now without exposing themselves, for not only is the telescope used for sighting, by fastening it to the weapon, but there is an invention, called the hyposcope, consisting of a series of mirrors in a tube below the line of sight.

To-day, the United States regular infantry and cavalry are armed with the short U. S. rifle, Springfield model 1903, which superseded the Krag-Jorgensen. See Artillery and Gunnery.