On this artificial lake, a fleet of armed vessels filled with soldiers, and with engines which discharged stones of five hundred pounds weight, advanced in order of battle, and engaged, almost upon a level, the troops which defended the ramparts.

*The irresistible force of the waters was alternately fatal to the contending parties, till at length a portion of the walls, unable to sustain the accumulated pressure, gave way at once, and exposed an ample breach of one hundred and fifty feet.

The Persians were instantly driven to the assault, and the fate of Nisibis depended on the event of the day.

The heavy-armed cavalry, who led the van of a deep column, were embarrassed in the mud, and great numbers were drowned in the unseen holes which had been filled by the rushing waters.

The elephants, made furious by their wounds, increased the disorder, and trampled down thousands of the Persian archers.