A float formedof an assemblage of pieces of timber fastened together, for the convenience of transporting them without dispersion; or for sustaining goods in transport; and sometimes for the saving of the lives of persons shipwrecked. A few years ago, Mr. Harrington took out a patent for a raft for transporting timber; the construction of which is described in the specification to be as follows: - The keel, stem post, and lowest timbers of the ribs. are to be formed and put together according to the usual way of constructing an ordinary ship. To form the bottom, balk timbers are to be laid together, side by side, lengthways of the vessel; and athwart these, others are to be closely laid, cutting their ends to suit the figure, then bracing the upper and lower timbers together. In this manner the lower parts of the vessel are to be formed, by packing the timbers crosswise closely, and connecting them by bolts and screws, leaving proper spaces open for slipping in the masts. In the upper part of this raft, suitable berths and cabins are to be provided for the navigators; the outside is to be planked all over, and caulked, pitched, and tarred in the usual manner; the masts and rigging are also to be of the ordinary kind.

This account is undoubtedly descriptive of a method of constructing a good mercantile raft, but the novelty of the principle of its construction we do not discover.

Much ingenuity has been exercised in the construction of life-rafts in cases of shipwreck, amongst which we may notice that of Mr. Canning, constructed of water-barrels and spars, so arranged that the parties on board are suspended on a platform high above the water to a horizontal yard-arm, preserved and supported in that position by cross spars, to which are attached the floating barrels.