That is nothing, answered I, to what takes place in Jupiter. He appears to be surrounded with belts, which are distinguished from each other, or from the spaces betwixt them, by their different degrees of light. These are land and seas--or at least parts of the planet differing in their nature. Sometimes these lands grow narrower, sometimes wider. New ones are formed in various parts, and some of the old ones disappear: and all these changes visible only through our best telescopes, are in themselves much more considerable than if our ocean were to inundate all the land, and leave its own bed to form new continents. Unless the inhabitants of Jupiter are amphibious, and live with equal ease either on land or in water, I hardly know what can become of them.[59] We see likewise great alterations on the surface of Mars, even from one month to another. In that short time seas overflow large continents, and retire by a flux and reflux a thousand times more violent than ours; or if this be not the case, some change equivalent to it takes place. Our planet is very quiet compared with these; we have great reason to congratulate ourselves, especially if it is true that in Jupiter countries as extensive as Europe have been set on fire. Set on fire! cried the Marchioness; that would be a great piece of news there. It would indeed, answered I. We have observed in Jupiter, for perhaps twenty years, a long stream of light more brilliant than the rest of the planet.[60] We have had deluges here, but very seldom; perhaps in Jupiter they have now and then a large conflagration as well as frequent deluges. But be that as it may, the brilliant light I spoke of is very different from another, which apparently is as old as the world, though it has but lately been discovered.[61] How can a light be formed for concealment? said she, that is something quite out of the common way. [Footnote 59: These lands surrounding Jupiter, which are sometimes few, and sometimes in great numbers, are apparently clouds.] [Footnote 60: I don't know that this observation is authentic.] [Footnote 61: The zodiacal light. Astron. Art. 844.] This light, I replied, is only visible at twilight, which is most frequently long enough, and of sufficient power to conceal it; and when it is not hid by the twilight, either the vapours of the horizon prevent us from seeing it, or without great attention we may even mistake it for twilight. However, about thirty years since it was discovered with certainty, and for some time gave great delight to the astronomers, whose curiosity wanted stimulating by something new. They might find as many new subaltern planets as they chose without feeling any interest in them. The two last moons of Saturn, for instance, did not enrapture them as Jupiter's satellites had done; custom destroys the power of every thing.