Page:The Moon (Pickering).djvu/45

Rh Moon, and known as rills. Each of the large craters is accompanied by two smaller ones formed upon their rims, and, in the case of Mauna Loa, intersecting and partially destroying the rim of the main crater. The rim of the crater of Mauna Loa is extremely rough, much more so than the comparatively smooth slopes of the mountain, and is riven by cracks and faults upon every side. This roughness is also characteristic of the Moon. Well toward the centre of the crater of Kilauea was found a conical pile of rocks, some 400 feet in height, which contained the great lake of liquid lava. This cone had been formed during the few previous years by gradual elevation from the crater floor. It was rough and very irregular.

There seems, indeed, to be no feature found upon the Moon which is not presented by these Hawaiian volcanoes, and there is no feature of the volcanoes that does not also have its counterpart upon the Moon. Even the cause of the bright streaks upon the Moon, as we shall see later, is partly illustrated in Hawaii.