Nautilus (Verne) from seawater) is the craft's primary power source for propulsion and other services. "Nautilus" is double-hulled, and is further separated into water-tight compartments. Its top speed is . Its displacement is submerged. In Captain Nemo's own words: "Nautilus" uses floodable tanks in order to adjust buoyancy and so control its depth. The pumps that evacuate these tanks of water are so powerful that they produce large jets of water when the vessel emerges rapidly from the surface of the water. This leads many early observers of "Nautilus" to believe that the vessel is some species of whale, or perhaps a
Jules Verne life. (Modern scholars have hypothesized that he suffered from colitis; Verne believed the illness to have been inherited from his mother's side.) Rumors of an outbreak of cholera in March 1849 exacerbated these medical concerns. Yet another health problem would strike in 1851, when Verne suffered the first of four attacks of facial paralysis. These attacks, rather than being psychosomatic, were due to an inflammation in the middle ear, though this cause remained unknown to Verne during his life. In the same year, Verne was required to enlist in the French military, but the sortition process spared him, to his