That is to say, answered the Marchioness, you are sure every thing is right, without knowing how it is; here is a little knowledge placed against a great deal of ignorance, but we must be content with it: I am very happy to have inhabitants restored to the moon; I am glad also that you give them a surrounding atmosphere, for it seems to me that a planet would be too naked without one. These two different airs, said I, one belonging to the earth, the other to the moon, tend to prevent the communication between the two planets. If it merely depended on the power of flying, who knows, as I yesterday said, but we may at some future time be sufficiently expert? All things considered, I think we must not expect this communication; the amazing distance at which they are placed, would be a considerable difficulty; and were this obstacle removed; were the two planets nearer together, it would be impossible to pass from one atmosphere to the other. Water is the atmosphere of fishes; they never pass into that of birds, nor the birds into theirs: they are not prevented by the distance, but the existence of both depends on their proper element. Our air, we find, is mixed with more dense and gross vapours than that of the moon; therefore an inhabitant of that world would be drowned if he entered our atmosphere, and fall lifeless on the earth. Oh! how glad I should be, exclaimed the Marchioness, for a shipwreck to cast a good number of them on the earth, we might then examine them at our leisure. But, I replied, if they were clever enough to navigate the surface of our atmosphere, and from a curiosity to examine us, should be tempted to draw us up like fishes; would that please you? Why not? answered she, laughing. I would voluntarily put myself in their nets, just for the pleasure of seeing the fishers. Remember, said I, you would be very ill by the time you reached the top of our air; we are not capable of breathing it above a certain height;[29] it is said that at the summit of some mountains we can scarcely do it. I wonder that people who are silly enough to believe that corporeal genii inhabit the purest regions of the air, should not tell us, as the reason for our receiving such short and unfrequent visits from these genii, that few of them understand diving, and even those who excel in it cannot remain long in our gross air. [Footnote 29: Respiration is difficult at the height of a league. Half a league higher it must be impossible.]