Alexander himself advanced towards the river Akesinês.[122] This is the only Indian river of which Ptolemy, the son of Lagos, has mentioned the size. He states that where Alexander crossed it with his army in boats and on inflated hides the current was so rapid that the waters dashed with foam and fury against the large and jagged rocks with which the channel was bestrewn. He informs us also that it was 15 stadia in breadth; and while the passage was easy for those who crossed upon inflated hides, not a few of those who were carried in boats perished in the waters, as many of the boats were dashed to pieces by striking against the rocks. From this description we may fairly conclude, if we institute a comparison, that the size of the river Indus has been pretty correctly stated by those who take it to have an average breadth of 40 stadia, while, where narrowest and of course deepest, it contracts to a breadth of 15 stadia, which I take to be its actual breadth in many parts of its course, for I conclude that Alexander selected a part of the Akesinês where the passage was widest, and where the current would consequently be slower than elsewhere. _Chapter XXI.—Pursuit after Pôros, nephew of the great Pôros—Conquest of the country between the Akesinês and the Hydraôtês—Passage of the latter river_ After crossing the river he left Koinos there upon the bank with his own brigade, and ordered him to superintend the passage of the river by those troops which had been left behind to collect corn and other supplies from the part of India which was now under his authority. Pôros he sent home to his capital with orders to select the best fighting men of the Indians, and to muster all the elephants he possessed, and to rejoin him with these. He resolved to pursue in person the other Pôros—the bad one—with the lightest troops in his army, for word had been brought that he had fled from the country of which he was the ruler; for, while hostilities still subsisted between Alexander and the other Pôros, this Pôros had sent envoys to Alexander offering to surrender into his hands both his person and the country over which he ruled, but this more from enmity to Pôros than friendliness to Alexander. On learning therefore that Pôros had not only been set at liberty, but had his kingdom restored to him, and that too with a large accession of territory, he was overcome with fear, not so much of Alexander as of his namesake Pôros, and fled from his country, taking with him as many fighting men as he could persuade to accompany him in his flight.