plain in headlong flight and slaying vast numbers of them.  The corps would probably have been annihilated, had they not in their flight reached a hill occupied by the baggage train, which gallantly came to their aid, and, attacking the horse and elephants from higher ground, gained a signal success.  The elephants, wounded by the javelins hurled down upon them from above, and maddened with the pain, turned upon their own side, and, roaring frightfully, carried confusion among the ranks of the horse, which broke up and fled.  Many of the frantic animals were killed by their own riders or by the Persians on whom they were trampling, while others succumbed to the blows dealt them by the enemy.  There was a frightful carnage, ending in the repulse of the Persians and the resumption of the Roman march.  Shortly before night fell, Jovian and his army reached Samarah, then a fort of no great size upon the Tigris, and, encamping in its vicinity, passed the hours of rest unmolested.  The retreat now continued for four days along the left bank of the Tigris, the progress made each day being small, since the enemy incessantly obstructed the march, pressing on the columns as they retired, but when they stopped drawing off, and declining an engagement at close quarters.  On one occasion they even attacked the Roman camp, and, after insulting the legions with their cries, forced their way through the preatorian gate, and had nearly penetrated to the royal tent, when they were met and defeated by the legionaries.  The Saracenic Arabs were especially troublesome.  Offended by the refusal of Julian to continue their subsidies, they had transferred their services wholly to the other side, and pursued the Romans with a hostility that was sharpened by indignation and resentment.  It was with difficulty that the Roman army, at the close of the fourth day, reached Dura, a small place upon the Tigris, about eighteen miles north of Samarah.  Here a new idea seized the soldiers.  As the Persian forces were massed chiefly on the left bank of the Tigris, and might find it difficult to transfer themselves to the other side, it seemed to the legionaries that they would escape half their difficulties if they could themselves cross the river, and place it between them and their foes.  They had also a notion that on the west side of the stream the Roman frontier was not far distent, but might be reached by forced marches in a few days.  They therefore begged Jovian to allow them to swim the stream.  It was in vain that he and his officers opposed the project; mutinous cries arose; and, to avoid worse evils, he was compelled to consent that five hundred Gauls and Sarmatians, known to be expert swimmers, should make the attempt.  It succeeded beyond his hopes.  The corps crossed at night, surprised the Persians who held the opposite bank, and established themselves in a safe position before the dawn of day.  By this bold exploit the passage of the other troops, many of whom could not swim, was rendered feasible, and Jovian proceeded to collect timber, brushwood, and skins for the formation of large rafts on which he might transport the rest of his army.