Any person who will put an empty tumbler, bottom upwards, into a bucket of water, will find that the water will not rise within the tumbler more than an inch at most. At that point it is arrested by the resistance of the air, which, unable to escape, and compressed into a narrow compass, forms a body that the other fluid cannot penetrate. It is on this simple and familiar principle, that the chemist keeps his gases, in inverted glasses, placing them on shelves slightly submerged in water. Thus it was, then, that the schooner continued to float, though nearly bottom upward, and with three inlets open, by which the water could and did penetrate. A considerable quantity of the element had rushed in at the instant of capsizing, but meeting with resistance from the compressed and pent air, its progress had been arrested, and the wreck continued to float, sustained by the buoyancy that was imparted to it, in containing so large a body of a substance no heavier than atmospheric air. After displacing its weight of water, enough of buoyancy remained to raise the keel a few feet above the level of the sea. As soon as Mulford had ascertained the facts of their situation, he communicated them to his companions, encouraging them to hope for eventual safety. It was true, their situation was nearly desperate, admitting that the wreck should continue to float forever, since they were nearly without food, or any thing to drink, and had no means of urging the hull through the water. They must float, too, at the mercy of the winds and waves, and should a sea get up, it might soon be impossible for Mulford himself to maintain his footing on the bottom of the wreck. All this the young man had dimly shadowed forth to him, through his professional experience; but the certainty of the vessel’s not sinking immediately had so far revived his spirits, as to cause him to look on the bright side of the future, pale as that glimmering of hope was made to appear whenever reason cast one of its severe glances athwart it. Harry had no difficulty in making Rose comprehend their precise situation. Her active and clear mind understood at once the causes of their present preservation, and most of the hazards of the future. It was not so with Jack Tier. He was composed, even resigned; but he could not see the reason why the schooner still floated. “I know that the cabin-doors were open,” he said, “and if they wasn’t, of no great matter would it be, since the joints ar’n’t caulked, and the water would run through them as through a sieve. I’m afeard, Mr. Mulford, we shall find the wreck going from under our feet afore long, and when we least wish it, perhaps.” “I tell you the wreck will float so long as the air remains in its hold,” returned the mate, cheerfully. “Do you not see how buoyant it is?—the certain proof that there is plenty of air within. So long as that remains, the hull _must_ float.”