wards, sideways, anywhere within its sphere of action; they are all picked up and sent forward. You thus see what a beautiful and important invention is that of the parabolic reflector for throwing forward the rays of light.
Before I go further into the subject of reflection let me point out a further mode of dealing with the direction of the light. For instance, here is a candle, and I can employ the principle of refraction to bend and direct the rays of light, and if I want to increase the light in any one direction, I must either take a reflector or use the principle of refraction. I will place this lens (fig. 56) in front of the candle and you
Fig. 56.
will easily see that by its means I can throw on to that sheet of paper a great light, that is to say, that instead of the light being thrown all about, it is refracted and concentrated on to that paper; so here I have another means of bending the light and sending it in one direc-
