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 Denmark to return in haste to Paris, but missed the birth on 3 August 1861 of his only biological son, Michel. Meanwhile, Verne continued work on the idea of a "Roman de la Science", which he developed in a rough draft inspired, according to his recollections, by his "love for maps and the great explorers of the world". It took shape as a story of travel across Africa and would eventually become his first published novel, "Five Weeks in a Balloon". In 1862, through their mutual acquaintance Alfred de Bréhat, Verne came into contact with the publisher Pierre-Jules Hetzel, and