The _heavy_ cavalry are divided into carabiniers, cuirassiers, and sometimes lancers. The two latter are frequently united, the cuirassiers being armed with the lance. These troops are seldom used for scouts, vanguards, and convoys; but are frequently employed to sustain the light cavalry. Their main duty is "_to appear on the field of battle and make the decisive charges_." The _light_ cavalry is composed of chasseurs, or troopers, hussars, and lancers. The latter, when composed of large men and mounted on heavy horses, are attached to the heavy cavalry. The _dragoons_ were formerly a mixed body of horse and foot, but it being found impossible to unite these two distinct arms in one, and the attempt having destroyed the usefulness of the body to act in either capacity, the term was applied to a mixed kind of cavalry between the heavy and the light horse. In more recent wars they have also been instructed as infantry and employed as foot-soldiers, till horses could be found in the enemy's country with which to mount them. But we believe there is no instance in more modern wars in which they have been employed at the same time in both capacities. This term is, very improperly, applied to all our cavalry; and some of the congressional wiseacres have recently experimented on one of our so-called regiments of _dragoons_, by dismounting it one year, selling its horses at auction, and changing its arms and equipments, and again, the next year, purchasing new horses, arms, and equipments for remounting it; and all this for _economy!_ The Roman cavalry at first wore a round shield and helmet, the rest of their body being nearly uncovered. Their arms were a sword and long thin javelin, or lance, with an iron head. They afterwards reduced the shield to a much smaller size, and made square, and their lance was greatly increased in size and length, and armed at both ends. In other respects they were armed in the same way as infantry. The use of the lance and the shield at the same time, of course rendered both nearly worthless. The Roman cavalry was superior to that of their enemies, except, perhaps, the light cavalry of the Parthians. The heavy armor which was sometimes worn by the ancients, like the _gens d'armes_ of the middle ages, rendered them greatly inferior to infantry in a close engagement. Tigranes, king of Armenia, brought an army of one hundred and fifty thousand horse into the field, against the Roman general Lucullus, who had only about six thousand horse and fifteen thousand foot. But the Armenian cavalry, called _cataphratti_ were so overburdened with armor, that when they fell from their horses they could scarcely move or make any use of their arms. They were routed by a mere handful of Roman infantry. The modern cavalry is much lighter, and, by dispensing with armor, shields, &c., it can move with much greater rapidity. A modern cavalry horse carries a weight of from two hundred and fifty to three hundred pounds, viz.: