This great star is our _Sun_ and since we owe everything we possess on Earth to him—light, heat, power and even life itself—he should and does stand in a class by himself, though after all he is just as much of a fixed star as the North Star, the Dog Star, or any of the thousands of other stars which we see as mere points of light in the sky. =How to See the Sun.=—You must never look directly at the Sun with the naked eye, for he is so powerful that his light will injure your sight for all time. [Illustration: FIG. 28.—SMOKING GLASSES OVER CANDLE FLAME.] [Illustration: FIG. 29.—SEEING THE SUN THROUGH SMOKED GLASSES.] There are several ways, though, to observe the Sun without danger to your eyes and as all of these are simple and cost nothing you can easily try them. The most common way is to take a bit of window glass, say an inch square, and smoke one side of it over the flame of a candle, as shown in Fig. 28. When this blackened glass is held closely to the eye, as shown in Fig. 29, and the latter is directed toward the Sun, a little circle of light will appear on the film of smoke and the surface of the Sun may be examined at length and without the least danger. A decided improvement over the smoked glass idea is to use a piece of red, or a piece of yellow glass, as an eyepiece, or, better, place the red and yellow glasses together and bind the edges with paper. Another plan to see the Sun without injury to the eyes is to make a hole with the point of a needle in a visiting card and look through the hole directly at the Sun. A still better view of the Sun can be obtained if a pinhole telescope is used. A telescope of this kind can be easily made without tools, metals or lenses. It is described and pictured in Chapter IX. To observe the Sun hold the pinhole end of the tube closely to your eye, to cut off all the outside light, and sight the tube so that the Sun shines directly into your eye through the pinhole, and you will get a very brilliant view of the great yellow star which we call the Sun. =What the Sun is Made of.=—When a candle is lit the wax of which it is made begins to melt and this is drawn up the wick where it is changed into gas and the burning gas forms the flame. The flame of a candle is made up of four parts, which are really layers of heated gas surrounding the wick, as shown in Fig. 30. In the center of the flame is the wick; the first layer of gas is at the bottom of the flame and this gives a greenish-blue light; the second layer is the dark and cool part of the flame; the third layer is a cone of heated gas which gives out the bright light, and surrounding this cone is a faint blue light which can just be seen.