The ray is reflected as obliquely from the glass as it strikes or falls upon it. Why is the reflection of the sun in a pond of water seen near the edge at noon? Because the angle of reflection is equal to the angle of incidence; and the observer must be nearly over the place where the rays strike, so that, when reflected, they may meet his eye. Where is the reflection seen in the morning or in the evening? It is seen nearer the middle of the pond; because the sun’s rays then fell more obliquely on the pond, and are reflected more obliquely to the eye. When an opaque object is placed between a candle and a wall, why will there be a shadow? Because the opaque object prevents the rays of light from falling on the wall. Why will the shadow be larger, the nearer the object is to the candle? Because the rays of light diverge, in every direction from the candle, in straight lines, and the nearer the object, the more rays will it intercept, as is represented in Fig. 9. [Illustration: Fig. 9.] In Fig. 9, let L represent the flame of a candle. When the object is placed at A, the shadow on the wall will extend from C to D; but when the object is moved nearer, as at B, the shadow will extend from E to F. Why does an object seem to be smaller, the farther it is from us? Because the angle at which the light from it strikes the eye, is less when at a distance, than when near to the eye. [Illustration: Fig. 10.] In Fig. 10, the diameter of the near circle is from A to B; but the diameter of the more distant circle, although just as large, seems only to be from C to D. Why does an object grow more dim the farther it is from us? Because the rays of light from it spread out in every direction; and fewer rays enter the eye when it is at a distance than when it is near by. What is the use of the telescope? It is used to view distant objects. Why can we see a distant object more distinctly with a telescope, than without one? Because the telescope enlarges the image of the object, and it also collects more light from that object than is collected by the unaided eye; thus, making the image distinctly visible. What class of objects do we view with a telescope? We view the heavenly bodies; the sun, moon, and stars. What is a spy-glass? It is a glass mostly used to view distant objects on the earth. Is the spy-glass like the telescope? The spy-glass is much like the telescope, only it is smaller. When looking through a spy-glass, how do objects appear? They seem to be brought nearer to us, and they appear larger. By whom are spy-glasses much used? Spy-glasses are much used by persons on board of vessels, while at sea. What instruments have we for magnifying small objects? We have magnifying glasses and microscopes. What are magnifying glasses? They are single glasses or lenses, used for magnifying small objects. By whom are magnifying glasses used?