Arms, instruments or weapons of offence, as opposed to defensive armor. Arms may in this sense be separated into two broad divisions of ancient and modern, reckoning the latter from the adaptation of gunpowder to purposes of war; and each of these may be again distinguished into missiles and weapons for hand-to-hand encounter. It is evident that offensive arms were prior in their invention and use to defensive coverings. In the earliest wars recorded in history, missiles were the principal weapons used. The bow (see Archery) and the javelin were in the period chronicled in the Old Testament the favorite weapons of the Assyrians, Medes, Persians, Parthians, and other oriental races; while their instruments for close fight were merely weak, straight daggers, acinaces, which word has been falsely translated seymitars. In the heroic wars, as described by Homer, missiles were still, in the hands of the leading chiefs and heroes, the most important weapons; a ponderous spear, hurled from the hand, and rarely if ever used to thrust with as a pike, being the instrument which began nearly all the duels of the champions, although they were often ended by the short sword.

The masses, indeed, seem to have fought in phalanx or close column with the pike, or sarissa, afterward the arm of the free Greeks of the republican cities, and of the barbaric kingdoms of Macedonia and upper Hellas. This was 24 feet long, and the spear-men held it in both hands, having their per-sons obliquely covered by the great round shield worn upon the left arm. The tactic on which the success of this arm depended was a closely serried phalanx, ordinarily of 12 or 24, occasionally of 50 files in depth. If the enemy succeeded in breaking this phalanx, the men had recourse to their swords, which, however, seldom proved of much use after the spears had given way. - The weapons of the Romans were a short, massive javelin, 6 feet long, including the triangular steel head of 18 inches, which they were wont to hurl into the lines of their enemy at 10 or 15 paces distant, and a short two-edged broadsword, probably in the first instance of Spanish origin and manufacture. This latter instrument, with which they were trained to stab rather than to strike, was that with which Rome cut her way to universal empire.

Her tactic, adapted to its use, was a loose array of open lines, each man standing three feet from his left and right hand com-rades, so that he had a clear space of six feet in which to manage his sword and buckler, and fighting as it were a duel or single combat, hand to hand, with his immediate oppo-nent, over whom his peculiar weapon, his singular skill in its use, and his incessant drilling in athletic exercises of all sorts, gave him immense advantage. With the Greeks and Romans infantry was the front and principal feature of their armies. In cavalry they were weak, and in the period of their greatest empire archery and slingers were contemptuously disregarded. - But with the decline of the Roman empires, especially that of the East, a new arm of the service took the lead in the steel-clad cavalry of the middle ages. Infantry, with hut two exceptions, the English and the Swiss, were almost powerless against it. The arms of these feudal troops were the lance, the mace, the battle-axe, and the two-handed sword; hut it is to the first that they owed their success.

This was a ponderous weapon of 18 feet in length, balanced by the great weight of its butt end, which was often nearly a foot in diameter at 20 inches from the extremity, having a notch cut out to admit the upper arm of the champion, which steadied it as it was laid in rest, supported by a projecting iron catch attached to the right-hand side of the knight's corslet. With this weapon, protruding 10 feet beyond their horse's chest, sheathed in panoply which defied any missiles which in that day could be brought against it, with the sole exception of the English clothyard arrow, infantry could seldom resist their shock. The arms of the infantry of this time were, besides the famous bows of the Englishmen, the bills - something similar to a short heavy scythe blade set erect on a shaft four feet long - leaden mallets, and long knives of the Anglo-Xorman archers; the pikes and halberts of the Swiss, which won them the day of Sempach, and did them good service at Morat, Granson, and Nancy, when the Austrian and Burgundian chivalry had dismounted; the crossbows of the Genoese; and the spears of the Scottish foot, who fought like the Greeks in phalanx. - Such were the distribution and relative importance of different arms during the greater part of the middle ages, and until the battle of Pavia, in 1525. This date marks the division between ancient and modern arms; for although gunpowder had been long before invented, it was at Pavia that the matchlock was first used in such a form as to make it of any practical value.

Even then it was a most imperfect and awkward weapon, fired from a rest. From this time firearms were improved, and the ancient offensive weapons, though they held their own for a considerable period, passed slowly out of use. The range of firearms was still very limited, and the accuracy of aim imperfect; and, till the musket was combined with the bayonet, the musketeer had no means of defending him self either against charging horse, or against infantry with long weapons, at close quarters, and he was therefore of necessity protected by pikemen. But at the beginning of the 17th century the bayonet was added to the arquebuse or musket, which had become from a matchlock a firelock, and now united in itself the properties of both pike and gun, and could be used indiscriminately as a missile or a weapon at close quarters. From this time, so rapid was the progress made in fire-arms, and so general their adoption, that the bullet soon became the arbiter of every battle, the combatants seldom coming to sufficiently close quarters to permit the use of weapons of the old form.

The American war of indepen-dence and the French wars of the revolution brought the rifle, which was by no means a new weapon - for the principle of rilling or screwing barrels, as it was then called, and its effect on the bullet, were known and used even in matchlocks as early as the 16th century - into general notice, and the invention of percussion doubled even its utility. From this time began that wonderful series of improve-ents in rifled small arms and cannon which has made the military rifle of to-day a most formidable weapon. The invention of the sim-ple modern percussion lock, of the Minie rifle bullet, of revolving pistols, and especially of breech-loading firearms of every kind, has enormously increased the means of offensive warfare. (See Artillery, Cannon, Gun, Gunnery, Gunpowder, Musket, Plstol, Rlfle.)