The regulation of the inundation, of the bed and level of the Euphrates, and of the level of the Tigris, was not only an assistance to agriculture, but to trade also, inasmuch as it facilitated the navigation in both streams. In this way trade received considerable support, and Nebuchadnezzar also paid attention to it beyond the borders of the Babylonian land. To his time apparently belongs the foundation of the Babylonian colony of Gerrha on the Arabian coast of the Persian Gulf. For the trade of Babylonia with South Arabia and the products of India which came to South Arabia (I. 305), it was important to avoid the transport by land and the middle trade of the Arabians, and to obtain those wares by direct marine trade with Babylonia. The building of the harbour city of Teredon at the mouth of the Euphrates, 400 miles below Babylon, which became the chief centre of the trade in Arabian spices, is, as we are definitely informed, the work of Nebuchadnezzar, and the Dedanites in whose land lay the colony of Gerrha (the modern Chatif) opposite the Bahrain islands, at a distance of 300 miles from Teredon, had been subjugated by Nebuchadnezzar (p. 329). The Gerrhæans brought the products and the incense of Arabia on board ship to Babylon; from hence it was sent up the river to Thapsacus, and from thence carried by land in every direction.[688] In this way the lucrative trade with South Arabia by the sea-route of the Persian Gulf must have been gained for Babylon. Hence it appears that Nebuchadnezzar built Teredon and founded Gerrha with the same object with which the Phenicians--in order to avoid the middle trade of the Arabians, and the difficulties of the caravan trade--arranged their navigation from Elath to South Arabia, in the time of Solomon, Jehoshaphat, and Uzziah of Judah. The Babylonians were already or subsequently became acquainted with the navigation on the Persian Gulf. Their voyages extended to the bold headland of the mountains of Maketa (Cape Mussendom), where it was possible to enter into direct communication with the Indians.[689] At a later time we hear only of the Gerrhæans as middle-men in the trade with the Sabæans, while in the Hebrew Scriptures the Rhegmæans and Dedanites carry on trade with Sabæa. The Gerrhæans carried the products of Arabia to Babylon by sea; then they passed not merely up the Euphrates, but also across the desert in a slanting direction to Syria. It must have been one of the most beneficial results of the hydraulic works of Nebuchadnezzar that the Euphrates could be navigated up the stream; and triremes could advance as far as Thipsach. Trade was greatly facilitated by the fact that the wares of India and Arabia could not only be brought by water to Babylon, but could also be conveyed along with the products of Babylonian industry to that city where the most crowded caravan routes from Cilicia, Syria, and Phoenicia, touched the Euphrates,[690] while, on