The gray sea-fogs played many scurvy tricks with the blockading-fleets, often letting the runners in right under the muzzles of the great guns. It was far easier to spy out a vessel in the darkest night than in the thick gray fog that enveloped all objects like a blanket. One of the strangest of all the pranks played by the fog occurred in December, 1863, in Charleston Harbor. A wary blockade-runner was creeping out of the harbor, within easy range of the great guns of the fleet, and all hands were trembling, lest at any minute should come the flash of a gun, and shriek of a shell, bearing a peremptory command to heave to. Suddenly the flash came, and was followed by the bang! bang! of great guns from all quarters of the fleet. But the fire seemed pointed in another direction; and the runner made the best of her way out to sea, thinking that some less fortunate vessel, trying to come in on the other side of the fleet, had been captured or blown out of the water. It turned out that a small fog-bank had taken the form of a gray steamer moving swiftly over the water, and had been fiercely cannonaded by the whole Federal fleet. This occurrence gave the Confederates an idea; and they began sending out dummies to engage the fleet, while the true blockade-runners would slip out unobserved in the excitement. One night as the tide was running out with great force, an old hulk was cut adrift from a wharf, and drifted down rapidly upon the Federal fleet. It was just after the exploits of the "Merrimac" had made Confederate rams famous, and the naval officers were a little nervous. The hulk drifted quite into the midst of the fleet before being observed; and when she was hailed she bore down on the largest of the men-of-war as though she were a powerful ram, steered by a commander of desperate bravery. The great gunboat's deck rang with the bo's'n's whistle, as the crew were piped to repel boarders, and to their quarters at the guns. A fierce fire was poured on the hostile craft, that came on sullenly, as if scorning to make reply. One by one the other vessels of the fleet drew near, and concentrated their fire on the wretched lumber schooner. It was too much for her; and she gave up the unequal combat, and sank to the bottom. For days after, the gallant tars of the squadron blockading Charleston rejoiced in the destruction of a "Rebel ram;" but none of them knew, that, while they were engaged in the desperate contest, two great blockade-runners, heavily laden with cotton, had slipped out of the harbor, and were well under way for Nassau.