As he foresaw the farther they sailed the more their vague terrors would increase, to deceive them, he kept two logs; one correct, retained for his own government, and the other open to general inspection, from which a certain number of leagues were daily subtracted from the sailing of the ships. The crews, though no faint-hearted fellows, had not as yet learned to place confidence in him. The slightest thing alarmed them. When about one hundred and fifty leagues west of Ferro, they picked up part of the mast of a large vessel, and the crews fancied that she must have been wrecked drifting ominously to the entrance of those unknown seas. About nightfall, on the 13th of September, he for the first time noticed the variation of the needle, which, instead of pointing to the north star, varied about half a point. He remarked that this variation of the needle increased as he advanced. He quieted the alarm of his pilots, when they observed this, by assuring them that the variation was not caused by any fallacy in the compass, but by the movement of the north star itself, which, like the other heavenly bodies, described a circle round the pole. The explanation appeared so highly plausible and ingenious that it was readily received. On the 14th of September they believed that they were near land, from seeing a heron and a tropical bird, neither of which were supposed to venture far out to sea. The following night the mariners were awestruck by beholding a meteor of great brilliancy--a common phenomenon in those latitudes. With a favourable breeze, day after day, the squadron was wafted on, so that it was unnecessary to shift a single sail. They now began to observe patches of weeds drifting from the west, which increased in size as they advanced. These, together with a white tropical bird which never sleeps on the water, made Columbus hope that he was approaching some island; for, as he had come but three hundred and sixty leagues since leaving the Canary Islands, he supposed the mainland still to be far off. The breeze was soft and steady, the water smooth. The crews were in high spirits, and every seaman was on the look-out, for a pension of ten thousand maravedis had been promised to him who should first discover land. Alonzo Pinzon in the _Pinta_ took the lead. On the afternoon of the 13th of September he hailed the Admiral, saying that from the flight of numerous birds and the appearance of the northern horizon, he thought there was land in that direction; but Columbus replied that it was merely a deception of the clouds, and would not alter his course. The following day there were drizzling showers, and two boobies flew on board the _Santa Maria_, birds which seldom wander more than twenty leagues from land. Sounding, however, no bottom was found. Unwilling to waste the present fair breeze, he resolved, whatever others thought, to keep one bold course until the coast of India was reached.