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 George Sand and Théophile Gautier among his earliest admirers. Several notable contemporary figures, from the geographer Vivien de Saint-Martin to the critic Jules Claretie, spoke highly of Verne and his works in critical and biographical notes. However, Verne's growing popularity among readers and playgoers (due especially to the highly successful stage version of "Around the World in Eighty Days") led to a gradual change in his literary reputation. As the novels and stage productions continued to sell, many contemporary critics felt that Verne's status as a commercially popular author meant he could only be seen as a mere genre-based storyteller,