One day while the boss was out this Dutch boy was standing before a window of the shop and he held a lens before his eye with one hand and another lens before the first lens with his other hand, as shown in Fig. 148. Imagine his surprise when the church he was looking at seemed to move much nearer to him, that is to say, the image of the church was greatly enlarged. The boy had made a wonderful discovery—he had discovered the _telescope_. When his master returned the boy showed him what he had done and it was not long before the great Galileo had a telescope and was startling the world by his wonderful discoveries of the moons of Jupiter, the rings of Saturn, the phases of Venus, the spots on the Sun and a hundred other wonders of the sky. A telescope is an arrangement of lenses in a tube for making the image of a distant object larger on the retina of the eye, or, as in the case of the fixed stars, for making them brighter. [Illustration: FIG. 148.—LIPPERHEY’S BOY DISCOVERS THE TELESCOPE.] The word telescope comes from two Greek words, the first, _tele_, which means afar, and the second, _scope_, which means to see, so that telescope means just what we should expect it to mean and that is to see afar. There are several kinds of telescopes, but there are only two kinds I want to make clear to you here; in the first kind the eye sees the object just as it is, that is, standing right side up, or _erect_. This kind of a telescope is called a _spyglass_, and is used to look at objects on the surface of the Earth. In the second kind of telescope the eye sees the object upside down, or _inverted_, and this kind of telescope, which is called an _astronomical telescope_, is just as good as the other for looking at the stars. =A Pinhole Telescope.=—Before describing how to make and use real telescopes which have lenses I want to tell you of a little scheme to see afar, and though it does not magnify the image of the object that is seen through it, yet it aids the naked eye when you are looking at the Sun and Stars. To make a pinhole telescope get a pasteboard tube about 1¼ inches in diameter and 5 or 6 inches long. A paper tube for mailing papers and sheet music is just the thing and can be bought at any stationery store. [Illustration: FIG. 149.—DISK OF CARDBOARD FOR PINHOLE TELESCOPE.] [Illustration: FIG. 150.—CROSS SECTION OF PINHOLE TELESCOPE.] Cut out a _disk_, or circular piece of cardboard just large enough to fit the tube, see Fig. 149, and push a pin point or needle through the center to make a small, clean hole. Next, glue this cardboard disk in the tube ½ an inch from one end. The disk must be glued in the tube so that no light can leak around the edge. If, now, you look at the Sun through the pinhole telescope, as shown in Fig. 150, you will get a better view of it than if you look at it through a pinhole in the cardboard alone, for the tube shuts out all the other rays of light from the eye.