The absence of an atmosphere on the moon, or at least the presence of only a very rare one, is proved by the suddenness with which a star will disappear when the moon passes between the star and us. Also surface features would not otherwise stand forth with such clearness nor shadows be so sharp and inky-black. When the moon passes in front of the sun at the time of an eclipse, its outline shows perfectly sharp against the yellow disk, even showing, like jagged saw-teeth, the "mountains of eternal light" which tower near the southern pole. When Venus makes a transit across the sun its whole edge is illuminated instead of being merely sharply defined, for Venus is enclosed in a wrapping of atmosphere. The spectroscope has proved that there is no water on the moon. If it is airless and waterless it consequently must be lifeless. But hold, a moment. Perhaps we go too fast with our this anti that and therefore, for here come reports from Pickering, one of our most tireless observers, who declares that there is a considerable amount of dampness still lodged in the deep cavities of the circular mountains, and that this dampness ascends in mists when the sun rises. These mists do not seem to float freely but cling to ridges and higher levels and later dissolve there. The outlines of these cavities are slightly blurred until the mist is banished. THE GRAY LAND ON THE MOON The curious gray areas which extend over two-fifths of the surface of the moon are the most conspicuous features to be seen with the unaided eye. These areas are comparatively smooth and level and invariably lower than the surrounding country. [Figure 160: THE GRAY LAND OF THE MOON.] The rest of the moon is extremely rough, the southern hemisphere in particular presenting the most singular circumambient scenery of thousands of round pits fringed by lofty ramparts of circular mountains. With the aid of a small telescope, the grayish spots on the moon somewhat resemble seas as they might appear at a great distance. Thus old astronomers, believing that they might at least be ancient sea-bottoms from which the water had evaporated, named them accordingly--although rather romantically. These names are still retained, disguised in Latin on the map of the moon and referred to in Latin by present day astronomers. Translated, however, they add a quaint glamour to the Gray Land and the eye wanders interestedly over "The Sea of Showers," "The Sea of Tranquillity," "The Sea of Clouds," "The Sea of Nectar," "The Gulf of Dews," "The Ocean of Storms," "The Bay of Rainbows," "The Marsh of Sleep" or "The Lake of Dreams."