Thursday, September 15th. This morning the temperature and peculiar appearance of the water, the quantities of gulf-weed floating about, and a bank of clouds lying directly before us, showed that we were on the border of the Gulf Stream. This remarkable current, running north-east, nearly across the ocean, is almost constantly shrouded in clouds, and is the region of storms and heavy seas. Vessels often run from a clear sky and light wind, with all sail, at once into a heavy sea and cloudy sky, with double-reefed topsails. A sailor told me that on a passage from Gibraltar to Boston, his vessel neared the Gulf Stream with a light breeze, clear sky, and studding-sails out, alow and aloft; while, before it, was a long line of heavy, black clouds, lying like a bank upon the water, and a vessel coming out of it, under double-reefed topsails, and with royal yards sent down. As they drew near, they began to take in sail after sail, until they were reduced to the same condition; and, after twelve or fourteen hours of rolling and pitching in a heavy sea, before a smart gale, they ran out of the bank on the other side, and were in fine weather again, and under their royals and skysails. As we drew into it, the sky became cloudy, the sea high, and everything had the appearance of the going off, or the coming on, of a storm. It was blowing no more than a stiff breeze; yet the wind, being north-east, which is directly against the course of the current, made an ugly, chopping sea, which heaved and pitched the vessel about, so that we were obliged to send down the royal yards, and to take in our light sails. At noon, the thermometer, which had been repeatedly lowered into the water, showed the temperature to be seventy; which was considerably above that of the air,--as is always the case in the centre of the Stream. A lad who had been at work at the royal mast-head, came down upon the deck, and took a turn round the long-boat; and looking very pale, said he was so sick that he could stay aloft no longer, but was ashamed to acknowledge it to the officer. He went up again, but soon gave out and came down, and leaned over the rail, "as sick as a lady passenger."