Mills, Frederick Wm. (Frederick William) · London : Dawbarn & Ward · leaf 22
made to vibrate through space, but to give a short explanation as to its composition so far as the same bears upon the practice of photography. White light is composed of a number of rays varying in refrangibility and the length of their vibrations. Each of these rays, which are visible to the eye,… … FIG. 2. These colours do not all appear equally bright to the eye, and in fact those at either extreme of the spectum, viz. : the
