main line in a hand:to-hand combat. Here the struggle was commonly brief--a very few minutes often decided the engagement. If the Persian line of battle was forced or broken, all was immediately regarded as lost--flight and rout followed. The cavalry, from its position on the wings, might attempt, by desperate charges on the flanks of the advancing foe, to stay his progress, and restore the fortune of the day, but such efforts were usually unavailing. Its line of battle once broken, a Persian army lost heart; its commander commonly set the example of flight, and there was a general rush of all arms from the battle-field. For success the Persians trusted mainly to their numbers, which enabled them, in some cases, to renew an attack time after time with fresh troops, in others to outflank and surround their adversary. Their best troops were undoubtedly their cavalry, both heavy and light. The heavy, armed in the old times with bows, and in the later with the javelins, highly distinguished itself on many important occasions. The weight of its charge must have been great; its offensive weapons were good; and its armor made it almost invulnerable to ordinary weapons. The light cavalry was celebrated for the quickness and dexterity of its manoeuvres. It had the loose organization of modern Bashi-Bazouks or Cossacks; it hung in clouds on the enemy--assailed, retreated, rallied, re-advanced--fled, and even in flight was formidable, since each rider was trained to discharge his arrows backwards with a sure aim. against the pursuing foe. The famous skill of the Parthians in their horse-combats was inherited from their Persian predecessors, who seem to have invented the practice which the later people carried to perfection. Though mainly depending for success on their numbers, the Persians did not wholly despise the use of contrivance and stratagem. At Arbela, Darius Codomannus had spiked balls strewn over the ground where he expected the Greek cavalry to make its attacks. [PLATE XXX., Fig. 5]; and, at Sardis, Cyrus obtained his victory over the Lydian horse by frightening them with the grotesque and unfamiliar camel. Other instances will readily occur to the reader, whereby it appears that the art of war was studied, and ingenuity allowed its due place in military matters, by this people, who showed a fair share of Oriental subtlety in the devices which they employed against their enemies.