Water Found on the Moon

This Lunar Sea is not a stagnant ocean; a solar tide sends it in a perpetual flow around the lunar axis, and strange storms and boilings and rushings of its waters occur, and at times cold winds and thunderings that ascend out of it into the busy ways of the great ant-hill above. It is only when the water is in motion that it gives out light; in its rare seasons of calm it is black. Commonly, when one sees it, its waters rise and fall in an oily swell, and flakes and big rafts of shining, bubbly foam drift with the sluggish, faintly glowing current. The Selenites navigate its cavernous straits and lagoons in little shallow boats of a canoe-like shape; and even before my journey to the galleries about the Grand Lunar, who is Master of the Moon, I was permitted to make a brief excursion on its waters.

The caverns and passages are naturally very tortuous. A large proportion of these ways are known only to expert pilots among the fishermen, and not infrequently Selenites are lost for ever in their labyrinths. In their remoter recesses, I am told, strange creatures lurk, some of them terrible and dangerous creatures that all the science of the moon has been unable to exterminate.

I am told by astronomers and physicists that all he [Cavor] tells is in absolute accordance with what was already known of the moon’s condition…..They know now pretty certainly that moon and earth are not so much satellite and primary as smaller and greater sisters, made out of one mass, and consequently made of the same material. And since the density of the moon is only three-fifths that of the earth, there can be nothing for it but that she is hollowed out by a great system of caverns. … And if the moon is hollow, then the apparent absence of air and water is, of course, quite easily explained. The sea lies within at the bottom of the caverns, and the air travels through the great sponge of galleries, in accordance with simple physical laws. The caverns of the moon, on the whole, are very windy places. As the sunlight comes round the moon the air in the outer galleries on that side is heated, its pressure increases, some flows out on the exterior and mingles with the evaporating air of the craters (where the plants remove its carbonic acid), while the greater portion flows round through the galleries to replace the shrinking air of the cooling side that the sunlight has left.