the standard of the Great King, and swelled the ranks of his vast army, which amounted (according to the best authorities) to above a million of men. Every available resource that the Empire possessed was brought into play. Besides the three arms of cavalry, infantry, and chariots, elephants were, for perhaps the first time in the history of military science, marshalled in the battle-field, to which they added an unwonted element of grotesqueness and savagery. The field of battle was likewise selected with great care, and artificially prepared for the encounter. Darius, it would seem, had at last become convinced that his enemy would seek him out wherever he might happen to be, and that consequently the choice of ground rested wholly with himself. Leaving, therefore, the direct road to Babylon by the line of the Euphrates undefended, he selected a position which possessed all the advantages of the Mesopotamian plain, being open, level, fertile, and well supplied with water, while its vicinity to the eastern and northern provinces, made it convenient for a rendezvous. This position was on the left or east bank of the Tigris, in the heart of the ancient Assyria, not more than thirty miles from the site of Nineveh. Here, in the region called by the Greeks Adiabene, extended between the Tigris and the river Zab or Lycus, a vast plain broken by scarcely any elevations, and wholly bare of both shrubs and trees. The few natural inequalities which presented themselves were levelled by order of Darius, who made the entire plain in his front practicable not only for cavalry but for chariots. At the same time he planted, in the places where Alexander’s cavalry was likely to charge, spiked balls to damage the feet of the horses.