Great reliance had been placed by the Persian king on the effects of the scythe-bearing chariots. It was designed to launch these against the Macedonian phalanx, and to follow them up by a heavy charge of cavalry, which it was hoped would find the ranks of the spearmen disordered by the rush of the chariots, and easily destroy this most formidable part of Alexander's force. In front, therefore, of the Persian centre, where Darius took his station, and which it was supposed the phalanx would attack, the ground had been carefully levelled and smoothed, so as to allow the chariots to charge over it with their full sweep and speed. As the Macedonian army approached the Persian, Alexander found that the front of his whole line barely equalled the front of the Persian centre, so that he was outflanked on his right by the entire left; wing of the enemy, and by their entire right wing on his left. His tactics were to assail some one point of the hostile army, and gain a decisive advantage; while he refused, as far as possible, the encounter along the rest of the line. He therefore inclined his order of march to the right so as to enable his right wing and centre to come into collision with the enemy on as favourable terms as possible though the manoeuvre might in some respects compromise his left. The effect of this oblique movement was to bring the phalanx and his own wing nearly beyond the limits of the ground which the Persians had prepared for the operations of the chariots; and Darius, fearing to lose the benefit of this arm against the most important parts of the Macedonian force, ordered the Scythian and Bactrian cavalry, who were drawn up on his extreme left, to charge round upon Alexander's right wing, and check its further lateral progress. Against these assailants Alexander sent from his second line Menidas's cavalry. As these proved too few to make head against the enemy, he ordered Ariston also from the second line with his light horse, and Cleander with his foot, in support of Menidas. The Bactrians and Scythians now began to give way, but Darius reinforced them by the mass of Bactrian cavalry from his main line, and an obstinate cavalry fight now took place. The Bactrians and Scythians were numerous, and were better armed than the horseman under Menidas and Ariston; and the loss at first was heaviest on the Macedonian side. But still the European cavalry stood the charge of the Asiatics, and at last, by their superior discipline, and by acting in squadrons that supported each other, instead of fighting in a confused mass like the barbarians, the Macedonians broke their adversaries, and drove them off the field. [The best explanation of this may be found in Napoleon's account of the cavalry fights between the French and the Mamelukes:--"Two Mamelukes were able to make head against three Frenchmen, because they were better armed, better mounted, and better trained; they had two pair of pistols, a blunderbuss, a carbine, a