Upon the world of which I speak night is illumined by phosphorescent lights. I have visited other worlds where night does not exist at all, where day and night do not succeed each other as upon the Earth, because every portion of their spheres is continuously supplied with light by several suns, which never leave them in darkness for an instant. There sleep is unnecessary, either for man, for animals, or for plants. Upon your planet sleep consumes a third portion of your life, its primary cause being the rotation of the earth on its axis, which produces day and night in succession, on the various parts of the globe. Upon these worlds where it is always day, the inhabitants never sleep, and it would greatly surprise them to learn, that there exists a humanity where a third of life is passed in a lethargy resembling death. [Sidenote: Phosphoric light] Not far from this, a world revolves where night is almost unknown, although it does not possess a nocturnal sun, as in the quadrilateral of Orion, and it has no satellites. The rocks of its mountains, being of a chemical composition that reminds one of the phosphates and the sulphates of barytes, store up the solar light received during the day; and during the night they radiate a sweet, calm, translucent light, which illumines the scenery with a tranquil nocturnal clearness. There, also, one sees curious trees, bearing flowers which shine in the evening like fire-flies. These resemble horse-chestnuts, but the snowy flowers are luminous. Phosphorus enters largely into the composition of this curious and singular world. Its atmosphere is constantly electrical; its animals are luminous, as well as its plants, and its humanity partakes of the same nature. [Sidenote: The passions phosphorescent.] The temperature is very high, and the inhabitants have not much need to invent clothes. Now, it happens that certain passions are manifested by the illumination of part of the body. This is, on a large scale, what takes place on a small scale in your terrestrial meadows, where one sees in the sweet summer evenings the glow-worms silently consumed in an amorous flame. In the fire-flies of the north, that you see in France, the male is winged and is not luminous; the female, on the contrary, is luminous, but does not possess the aerial faculty. In Italy the two sexes are winged, and both can become luminous. The humanity which I am describing to you has all the advantages of this latter type.