Alexander collected all the canoes and boats which he could obtain up and down the river. He built large rafts, attaching to them the skins of beasts sewed together and inflated, to give them buoyancy. When all was ready, they began the transportation of the army in the night, in a place where the enemy had not expected that the attempt would have been made. There were a thousand horses, with their riders, and four thousand foot soldiers, to be conveyed across. It is customary, in such cases, to swim the horses over, leading them by lines, the ends of which are held by men in boats. The men themselves, with all the arms, ammunition, and baggage, had to be carried over in the boats or upon the rafts. Before morning the whole was accomplished.