Chro-mat′ic Ther-mome-ter.
When the edge of a rectangular plate of glass is applied to a piece of heated metal, or other substance having a temperature different from that of the glass, and exposed to a beam of polarized light, colored fringes are developed. As the different tints depend on the different temperatures of the glass (which is supposed to be known), and that of the object to which it is applied, the color of the central fringe affords a means of inferring approximately the temperature of the substance. Brande.