_Gulf of Mexico._――The Gulf of Mexico washes the shores of Florida, Alabama, Mississippi, and Louisiana, on the side of the United States. It extends between the eighteenth and thirtieth parallels of north latitude, and is nearly of a circular form, but somewhat elongated from east to west. In the latter direction it is one thousand one hundred and fifty miles long; in the transverse direction it is about nine hundred and thirty. It opens in a south-east direction, between the peninsula of Yucatan and Florida, or the capes Catoche and Sable, which are about four hundred and sixty-five miles distant from each other. The Island of Cuba divides this opening into two channels: the one to the south-west, communicating with the Sea of the Antilles, and the other to the north-east with the Atlantic, by means of the Straits of Bahama or Florida. South from the mouth of the Rio del Norte, round about the mouth of the Rio Alvarado, an extent of six hundred miles, this gulf does not present a single good port, as Vera Cruz is merely a bad anchorage amidst shallows. The Mexican coast may be considered a sort of dike, against which the waves, continually agitated by the trade-winds blowing from east to west, throw up the sands carried by the violent motion. The rivers descending from the Sierra Madre, have also contributed to increase these sands, and the land is gaining on the sea. No vessels, says Humboldt, drawing more than twelve and a half inches water, can pass over these sand-bars without danger of grounding. The Mississippi is the principal tributary of the Gulf of Mexico, and carries down with it, besides its vast body of waters, a prodigious quantity of organic and unorganic debris. The town of New Orleans, near the mouth of this river, is the principal commercial station along the whole gulf. In the middle of the gulf the winds blow regularly from the north-east; but they vary considerably on approaching the shore. From the Mississippi, along the Florida coast, the south-west wind blows violently in the months of August, September, and October; the north wind prevails during the other nine months. Between the Mississippi and San Bernardo, the wind generally blows in the morning from the south-east or east-south-east, and in the evening from the south-west. Between Catoche and Campeachy the reigning wind, during a great part of the year, blows from the north-east; but from the end of April to September, it comes from the opposite direction. The most remarkable current in the gulf, is that called the _Gulf Stream_, described in the following chapter. GENERAL REMARKS ON BAYS.