Page:The Music of the Spheres.djvu/315

 stars invisible. This would also unveil many of the smaller stars that are not seen here without optical aid—and every star would "burn" but none would "twinkle." In the morning of that long lunar day of 354 hours, the yellow face of the sun would slowly push its gayly bedecked head above the black rim of the horizon unheralded by a dawn; neither would twilight trail behind it when it sank beyond our sight after the long day was done, for these phenomena are due entirely to the light-reflecting and refracting power of an atmosphere.

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 and that and therefores, 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.