[Illustration: FIG. 105.—REAL VOLCANOES.] The volcanoes of California, Japan and the Hawaiian Islands are, many of them, still active, while those on the Moon have long since become extinct. This is easily accounted for, since the mass of the Moon is very small compared with that of the Earth, and hence, the Moon has cooled off more quickly than the Earth. The result is that while the Earth is yet hot and teeming with life and activity, the Moon is cold, and dead and silent. =Seeing the Moon With the Naked Eye.=—If you look at the full Moon with the naked eye it will appear as a great, silvery-bright disk, and about the same size as the Sun. Look again and you will see that some parts of it are much brighter than others, while another and closer observation will show you that the light and shaded parts take on the expression of a man’s face, as shown in Fig. 106. This is the famous _Man in the Moon_, and once you make out the likeness you will never again be able to look the full Moon in the face without seeing the man in it. [Illustration: FIG. 106—NAKED EYE DRAWING OF FULL MOON.] When we look at the Moon we always see the same side of it, which will be readily understood when we come to the turning of the Moon on its axis. As the Moon revolves about the Earth, you will see, if you look toward the west at the right time of the month, just at dusk, a pale _crescent_ of light, and very soon after the Sun sets it drops out of sight below the horizon. A few nights later the Moon will be seen, over in the sky toward the east; its crescent shape grown into the first quarter, and the Moon looks as if it was split in two. As the nights go by the Moon _waxes_ until it is _gibbous_ and finally the full Moon—with the man in it—stands out round and clear and bright. It is a good idea at this time, that is, when the Moon is full, to make a drawing of her face, and the best time to do it is shortly after twilight, for later in the evening the Moon is so bright it is hard to see the details. After this the Moon begins to _wane_; it again becomes gibbous; then reaches its last quarter later only a crescent can be seen, and she finally disappears. At times when the crescent is bright the whole dark disk of the Moon can be seen glowing dimly with a reddish, copper color, and this is called the _old Moon in the new Moon’s arms_. This copper-colored glow is the _Earth-shine_ on the Moon, that is, the sunlight on the Earth, which is reflected to the Moon and back again to us. On one side of the Moon you may be able to see a dark oval spot which is marked _Grimaldi_ on the maps of the Moon. Grimaldi is a great plain, having nearly 14,000 square miles in it, with mountains flanking it on the sides. This is another good eyesight test, for it takes a mighty sharp eye to see it without a glass. These and a dozen other interesting things on the Moon can be seen without a telescope.