Page:"N" Rays (Garcin).djvu/56

34

When a pencil of "N" rays is directed either on a small spark, flame, or a phosphorescent substance previously exposed to the sun's rays, or, again, to a platinum plate heated to dull redness, the light emitted by these various sources is seen to increase in glow. In these experiments, one operates on sources emitting light spontaneously. I asked myself whether one could not generalize these experiments by using a body not emitting light itself, but reflecting that which reaches it from an external source. I consequently carried out the following experiment: a slip of white paper, 15 mms. long and 2 mms. broad, is fixed vertically to a wire holder; the room being made dark, the slip is dimly lighted by projecting laterally on it a pencil of light, emitted by a small flame shut up in a box, in which a vertical slit is pierced.

On the other hand, the rays are produced