Note 433 — 1843.

It is simply a half-cylinder, 20 feet long by 1 foot 9 inches wide, and 3 feet deep, strengthened internally by hollow tubes, and deriving its buoyancy from an ingenious distribution of water-tight compartments, which not only preserve the flotation but provide seats for the troops. To render the contrivance more efficient for rafts or bridging purposes, a similar half-cylinder is attached to its consort by strong hinges and bolts. When shut its form is cylindrical; when open, two boats in rigid connection, taking the same swing in the water—the same motion on the wave. In this Siamese connection it is intended always to be used; and fitted as it is with all the necessary details, and the means of applying a rudder or an oar for steerage at any end, it appears to be adequate for all the uses and contingencies, not only of a pontoon, but of an ordinary passage-boat. It moreover aspires to the merciful functions of a lifeboat, being capable, without risk of capsizing or sinking, of venturing out in heavy seas to save human life imperilled by squalls or shipwreck.