For this purpose a number of old whaling vessels were purchased at New Bedford and New London, freighted with granite from the Bay State, and taken to Port Royal as a rendezvous, whence they were to be convoyed to their destination. The people of Savannah, after the capture of Port Royal and Beaufort, anticipating the approach of the Federal fleet, volunteered the work on their own behalf and blockaded their own port by similar means. The fleet was therefore at liberty to repair to Charleston, and within sight of the walls of Sumter, to shut out the rebellious people of that city from the ocean. The “Stone Fleet” sailed from Port Royal on the 18th of December, accompanied by the steamers Cahawba, Philadelphia and Ericsson, to tow and assist, the whole convoyed by the Mohican, Captain Gordon, the Ottawa, Captain Stevens, and Pocahontas, Captain Balch. The fleet arrived off Charleston harbor the next day and preparations were made for sinking them in their places. Each of the weather-beaten and storm-tossed old vessels that had so long borne the stars and stripes in every latitude, were now to make a stubborn protest against treason by keeping watch at the very door of its birth-place. They were furnished with ingenious contrivances and plugs, the withdrawal of which would allow the water to flow in and sink them on the floor of the channel. The sinking of the fleet was intrusted to Captain Charles H. Davis, formerly on the Coast Survey, and ever since more or less intimately connected with it. It is remarkable that when, in 1851, an appropriation was made by the Federal Government for the improvement of Charleston harbor, and, at the request of South Carolina, a commission of army and navy officers was appointed to superintend the work, Captain Davis was one of the commission, and for three or four years was engaged in these operations. The present attempt was of somewhat different character. The entrance by the main ship channel runs from the bar to Fort Sumter, six miles, nearly south and north. The city is three miles beyond, bearing about N. W. The other channels are Sanford’s, Swash, the North, and Maffit’s, or Sullivan’s Island, which need not to be particularly described. Only the latter is practicable for vessels of any draught, but all serve more or less to empty the waters discharged by the Ashley and Cooper rivers. Over the bar, at the entrance of the main ship channel, is a narrow passage, through which vessels may carry eleven feet at low water; about seventeen at high water. The plan of Captain Davis for closing the harbor proceeded on the following principles: The obstructions were to be placed on both sides of the crest of the bar, so that the same forces which created the bar might be relied on to keep them in their places.