[548] In the speech which Arrian (v. 25, 26) puts into the mouth of Alexander, the most curious point is, the geographical views which he promulgates. “We have not much farther now to march (he was standing on the western bank of the Sutledge) to the river Ganges, and the great Eastern Sea which surrounds the whole earth. The Hyrkanian (Caspian) Sea joins on to this great sea on one side, the Persian Gulf on the other; after we have subdued all those nations which lie before us eastward towards the Great Sea, and northward towards the Hyrkanian Sea, we shall then sail by water first to the Persian Gulf, next round Libya to the pillars of Herakles; from thence we shall march back all through Libya, and add it to all Asia as parts of our empire.” (I here abridge rather than translate). It is remarkable, that while Alexander made so prodigious an error in narrowing the eastern limits of Asia, the Ptolemaic geography, recognized in the time of Columbus, made an error not less in the opposite direction, stretching it too far to the East. It was upon the faith of this last mistake, that Columbus projected his voyage of circumnavigation from Western Europe, expecting to come to the eastern coast of Asia from the West, after no great length of voyage. [549] Arrian, v. 28, 7. The fact that Alexander, under all this insuperable repugnance of his soldiers, still offered the sacrifice preliminary to crossing—is curious as an illustration of his character, and was specially attested by Ptolemy. To mark the last extremity of his eastward progress, he erected twelve altars of extraordinary height and dimension on the western bank of the Hyphasis, offering sacrifices of thanks to the gods, with the usual festivities, and matches of agility and force. Then, having committed all the territory west of the Hyphasis to the government of Porus, he marched back, repassed the Hydraotes and Akesines, and returned to the Hydaspes near the point where he had first crossed it. The two new cities—Bukephalia and Nikæa—which he had left orders for commencing on that river, had suffered much from the rains and inundations during his forward march to the Hyphasis, and now required the aid of the army to repair the damage.[550] The heavy rains continued throughout most of his return march to the Hydaspes.[551] [550] Arrian, v. 29, 8; Diodor. xvii. 95. [551] Aristobulus ap. Strab. xv. p. 691—until the rising of Arkturus. Diodorus says, 70 days (xvii. 73), which seems more probable.