On the 13th of September, in the evening, Columbus, for the first time, noticed the variation of the needle, a phenomenon which had never before been remarked. He at first made no mention of it, lest his people should be alarmed; but it soon attracted the attention of the pilots, and filled them with consternation. It seemed as if the very laws of nature were changing as they advanced, and that they were entering another world, subject to unknown influences. They apprehended that the compass was about to lose its mysterious virtues, and, without this guide, what was to become of them in a vast and trackless ocean? Columbus tasked his science and ingenuity for reasons with which to allay their terrors. He told them that the direction of the needle was not to the polar star, but to some fixt and invisible point. The variation, therefore, was not caused by any fallacy in the compass, but by the movement of the north star itself, which, like the other heavenly bodies, had its changes and revolutions, and every day described a circle round the pole. The high opinion they entertained of Columbus as a profound astronomer gave weight to his theory, and their alarm subsided. They had now arrived within the influence of the trade-wind, which, following the sun, blows steadily from east to west between the tropics, and sweeps over a few adjoining degrees of the ocean. With this propitious breeze directly aft, they were wafted gently but speedily over a tranquil sea, so that for many days they did not shift a sail. Columbus in his journal perpetually recurs to the bland and temperate serenity of the weather, and compares the pure and balmy mornings to those of April in Andalusia, observing that the song of the nightingale was alone wanting to complete the illusion.... They now began to see large patches of herbs and weeds, all drifting from the west. Some were such as grow about rocks or in rivers, and as green as if recently washed from the land. On one of the patches was a live crab. They saw also a white tropical bird, of a kind which never sleeps upon the sea; and tunny-fish played about the ships. Columbus now supposed himself arrived in the weedy sea described by Aristotle, into which certain ships of Cadiz had been driven by an impetuous east wind.