For sailing on the surface the boat was fitted with a single jury-mast carrying a mainsail jib, which could be unshipped when submarine navigation was required. By admitting water she sank to the required depth, and was then propelled by the method already referred to. A glass dome, a compass, a pump for expelling the water when necessary, and a gauge for testing depth, which Fulton called a bathometer, constituted the ‘works.’ The torpedo was an apparatus made of copper filled with gunpowder, “arranged in such a manner that if it strikes a vessel or the vessel runs against it, the explosion will take place and the bottom of the vessel be blown in or so shattered as to ensure her destruction.”[3] The weapon was to be fixed to the bottom of the victim by means of a barbed point on the chain used for towing it. Fulton approached Napoleon, who authorized Forfait, the latest Minister of Marine, to advance the sum of 10,000 francs for the purpose of perfecting the _Nautilus_. He also granted Fulton an interview. When, in the autumn of 1801, he expressed a wish to see the submarine, the vessel had been broken up. Here the matter ended, and the ingenious American turned his thoughts in the direction of steam navigation. The _Nautilus_ was his one and only experiment in underwater craft.[4] The first ship to be actually sunk during hostilities by submarine was the Federal 13–gun frigate _Housatonic_, of 1264 tons. She went down off Charleston on the 17th February, 1864, during the American Civil War, as the result of being attacked by a spar-torpedo carried by the Confederate submarine _Hunley_, so named after her designer, Captain Horace L. Hunley. Unfortunately the underwater boat was also a victim, and she carried with her her fourth crew to meet with death as a consequence of misadventure. On the first occasion the boat was swamped and eight men were drowned, on the second a similar disaster overtook her, with the loss of six of her crew, on the third she descended and failed to come up. Small wonder that the _Hunley_ came to be known as ‘the Peripatetic Coffin.’ The shape of the _Hunley_ was cylindrical. For’ard and aft were water ballast tanks operated by valves, and additional stability was given by a sort of false keel consisting of pieces of cast iron bolted inside so as to be easily detachable should it be necessary to reach the surface quickly. On each side of the propeller, worked by the hand-power of eight men, were two iron blades which could be moved so as to change the depth of the vessel. The pilot steered from a position near the fore hatchway.