This fact of reflection and the fact that the so-called angle of reflection is the same as the angle of incidence, or, in other words, the angle at which the light falls upon the object, explains a familiar sight. Have you never seen, late in the afternoon, when the sun is above the horizon, a blaze upon a hill side, so bright that your first thought is it must be a house on fire? You saw it suddenly; and, if you walk a few steps to the right or left, it as suddenly disappears; to reappear, however, when you resume your former position. By this time you know it is not a fire, but the reflection of the sun from some window or tin roof. The light, striking down upon it, glances off, and, as you happen to be in the line of its angle of reflection, strikes you full in the eyes. But move your position, so as to get out of the “line of fire,” and the reflected ray passes you by without attracting your notice.