The navigation of the ship now became a business requiring the utmost caution. Owing to the invisibility of the heavenly bodies it was impossible to ascertain the precise amount of error in the compass. The treacherous Nantucket Shoals, with their changeful currents, were close at hand. The Captain had his chart spread before him, and on it he was tracing the course of the ship as shown by the soundings. She would run twelve miles, and the chart would show that she ought then to be in thirty-four fathoms. The sounding-machine would give the depth. If it was less than thirty-four fathoms, she was north of her apparent course; if more, she was south. She was literally feeling her way. It was nearly 6 P.M., and a fine misty rain narrowed the horizon down to a small circle of two miles in diameter. The _Golden Fleece_ was slowed down to eight knots, and soundings were taken every fifteen minutes. Suddenly the dull blast of a steam-whistle was heard far off the starboard bow. The first officer hastily drew out his watch and counted the seconds. Nearly half a minute passed, and then came another blast, three times as long as the first. "The light-ship," said the first officer. "Yes," said the Captain, who had mounted the bridge at the first sound. "We are fully two miles further north than I thought; too much current allowance, I guess. However, I shall now steer to pass eight miles due south of Shinnecock Light, at a point 40° 43' north and 72° 30' west. The course is west, true, and the distance 113 miles; but we must make some allowance for current--not much, though, with this wind. It's ebb-tide, and it will hardly be likely now to set toward the beach, as it often does." The Captain made some more calculations, and then gave out the compass course. The speed of the ship was increased to twelve knots, and the deep-sea sounding-machine was used once an hour all night. At four o'clock in the morning the rain had ceased, and another dense fog had set in. The soundings indicated that a point about eight or nine miles due south of Shinnecock Light had been reached. The Captain now gave out the course as west, and the distance as sixty-two miles; but he was very uncertain as to the deviation of the compass, so he ordered speed reduced to ten knots, while the lead was to be cast every half-hour. A fresh northeasterly wind sprang up, raising a choppy sea, and transforming the fog into a driving mist. The soundings ran very irregularly, the lead showing 18, 17-1/2, 20, 22, and 19 fathoms without any apparent guidance. The Captain walked the bridge anxiously. The soundings began to run 18, 17-1/2, 17, 17, 16-1/2, 16, 15, 14, 13-1/2, 13, 14, and 13 fathoms. "Too far to the south, as sure as I live!" muttered the Captain. "How did we do it? But we're sure to make one of the holes." And then he added aloud, "Slow down to six knots." Suddenly the officer at the sounding-machine away aft sung out, "Twenty-one fathoms, sir!"