Page:The Music of the Spheres.djvu/320

 On account of the vividness of the shadows, moon-mountains are best observed during the first and last quarter of the moon. A good time to begin observing with a glass is when the moon is a narrow crescent in the western sky. The most prominent object in the narrow crescent is the Mare Crisium or the Sea of Crises, 380 miles long. South of Mare Crisium is Mare Fecunditatis, the Sea of Fecundity and Mare Nectaris, the Sea of Nectar. When these three "Seas" are visible with Mare Tranquillitatis just coming into view, the moon is between 5 and 6 days old, that is, 5 or 6 days after new moon. The Leibnitz mountains may then