By tables kept for several years at Malta, it appears that the Mediterranean, at that point, varies in level between winter and summer no less than three feet. In winter, when there is no evaporation, and when the quantity of water falling in the immediate vicinity of the Mediterranean is greatest, the level is lowest. The cause, I should take to be the pressure of wintry wind. In like manner, those erratic movements in the Straits may result from difference of atmospheric pressure without and within. These currents, by the testimony of the ancients, have not held from the beginning--they have been the results of successive modifications of the channel. This is singularly borne out by the traditions of the neighbouring people and the geological features of the coast. Eldressi narrates, as an old and popular story of his day, that “the Sea of Cham (Mediterranean) was in ancient times a lake surrounded on all sides, like the Sea of Tabaristan (Caspian), the waters of which have no communication with any other seas. So that the inhabitants of the extreme west invaded the people of Andalusia, doing them much injury, which they, in like manner, did to the others, living always in war, until the time of Alexander,[28] who consulted his wise men and artificers about cutting that arid isthmus and opening a canal. Thereupon they measured the earth, and the depth of the two seas, and saw that the Sea of Cham was not much lower than the Sea Muhit, (Ocean); so they raised the towns that were on the coast of the Sea of Cham, changing them to the high ground. Then he ordered the earth to be dug out; and they dug it away to the bottom of the mountains on both sides; and he built there two terraces with stones and lime the whole length between the two seas, which was twelve miles; one on the side of Tankhe (Tangier), and one on the side of Andeluz. When this was done, he caused the mound to be broken, and the water rushed in from the great sea with violence, raising the waters of the Sea of Cham, so that many cities perished, and their inhabitants were drowned, and the waters rose above the dykes, and carried them away, and did not rest until they had reached the mountains on both sides.” The Moors have also a Myth. “The sea,” they say, “was created fresh, but exalting itself against its Maker, gnats were sent to drink it up. It then humbled itself in the stomach of the gnats, and prayed to be relieved, so the gnats were ordered to vomit it forth again, but the salt remained from the stomach of the gnats an eternal sign of its disobedience.” Before suggesting the interpretation of these Myths, I will point out the change which the coasts and channel have undergone.