11. Aristobulus relates that Alexander himself, when he was sailing up the river, and directing the course of the boat, inspected the canals, and ordered them to be cleared by his multitude of followers; he likewise stopped up some of the mouths, and opened others. He observed that one of these canals, which took a direction more immediately to the marshes, and to the lakes in front of Arabia, had a mouth very difficult to be dealt with, and which could not be easily closed on account of the soft and yielding nature of the soil; he (therefore) opened a new mouth at the distance of 30 stadia, selecting a place with a rocky bottom, and to this the current was diverted. But in doing this he was taking precautions that Arabia should not become entirely inaccessible in consequence of the lakes and marshes, as it was already almost an island from the quantity of water (which surrounded it). For he contemplated making himself master of this country; and he had already provided a fleet and places of rendezvous; and had built vessels in Phœnicia and at Cyprus, some of which were in separate pieces, others were in parts, fastened together by bolts. These, after being conveyed to Thapsacus in seven distances of a day’s march, were then to be transported down the river to Babylon. He constructed other boats in Babylonia, from cypress trees in the groves and parks, for there is a scarcity of timber in Babylonia. Among the Cossæi, and some other tribes, the supply of timber is not great. The pretext for the war, says Aristobulus, was that the Arabians were the only people who did not send their ambassadors to Alexander; but the true reason was his ambition to be lord of all. When he was informed that they worshipped two deities only, Jupiter and Bacchus, who supply what is most requisite for the subsistence of mankind, he supposed that, after his conquests, they would worship him as a third, if he permitted them to enjoy their former national independence. Thus was Alexander employed in clearing the canals, and in examining minutely the sepulchres of the kings, most of which are situated among the lakes.