The next morning she woke to the first ray of light through the window.
The walls were of stained pine, shellacked to a glow that reflected every ray of light that entered the large windows.
A ray of light is directed upon the mirror, and the motion of the latter, due to the varying strengths and direction of the received currents, is made to write the transmitted signals upon a strip of bromide photographic paper about three inches wide.
The geometrical theory first requires a consideration of the path of a ray of light falling upon a transparent sphere.
Hence, if a prism is placed in front of the eye with its base towards the nose, a ray of light falling upon it will be bent inwards, and seem to come from a point farther out from the axis of vision.