You cannot do better than to point your little homemade telescope at the Moon, stop, look and rediscover the mountains on it and be as surprised and delighted as Galileo was, three hundred years ago. To see the mountains at their best do not wait until the Moon is full, for the sunlight then shines directly on top of the mountains and there are no shadows to help the eye to gauge breadths and heights. The best time to see the mountains is when the Moon is in its first or its last quarter, for then they are well brought out by the bright sunlight shining on them from the side and the black shadows which they cast on the other side. The great smooth stretches seen on the Moon are called seas. It may be that in the long ago they were really seas, but it is more likely that Galileo and the early observers whose telescopes were little better than yours thought they were seas. Then there are huge cracks or gorges on the surface of the Moon, which start from some of the craters and run for hundreds of miles in every direction. A number of these gorges start from a volcano named _Tycho_ (pronounced Ti´-co) and make the Moon look as if it is cracked; and it is likely that when the Moon cooled down from its melted state after having been shot off from the Earth it did crack in many places. Fig. 158, which is a good telescopic view of the Moon, shows some of these great cracks radiating from Tycho. [Illustration: FIG. 158.—FULL VIEW OF MOON.] To show on a small scale how the Moon cracked on cooling down Nysmith filled a glass globe with cold water and then sealing the globe he plunged it into hot water. The slow expansion of the cold water by the hot water caused the globe to crack as shown in Fig. 159, and by comparing the pictures it will be seen that the cracks on the Moon and in the glass globe are very much alike. There is a mountain called Aristarchus[1] (pronounced Ar-is-tar´-cus) which is believed to be formed of pure metal because it shines brighter than any other mountain on the Moon. Its position is shown on the map, Fig. 160. [Illustration: FIG. 159.—GLASS GLOBE CRACKED.] The instant you look through your glass at the Moon the man which shows so plainly to the naked eye vanishes like a coin in a magician’s fingers and instead you will see a new world covered with plains and mountains. But if you will look at the Moon when it is nine or more days old, you will see with the aid of your glass and a little imagination the Moon girl, as shown in Fig. 161. You should have no trouble in finding her, for the _Apennines_ form her crown while Tycho shines upon her breast like a great yellow diamond. [Footnote 1: Aristarchus was a Greek who lived 200 years before Christ. He taught that the earth was round.] [Illustration: FIG. 160.—MAP OF THE MOON.] [Illustration: FIG. 161.—THE MOON GIRL.]