After their breakfast, Nemo shares a blueprint of his 230-foot-long sub: "Here,
Professor Aronnax, are the different dimensions of this boat now transporting
you. It's a very long cylinder with conical ends. It noticeably takes the shape
of a cigar, a shape already adopted in London for several projects of the same
kind." Experimental submarines indeed pre-dated Verne's novel, although none
had approached the capabilities of the Nautilus.