nMelanoscope(Opt) An instrument containing a combination of colored glasses such that they transmit only red light, so that objects of other colors, as green leaves, appear black when seen through it. It is used for viewing colored flames, to detect the presence of potassium, lithium, etc., by the red light which they emit.
Century Dictionary and Cyclopedia
nmelanoscopeAn instrument devised by Lommel to distinguish between the flames of substances which in the spectroscope exhibit red bands. It consists of a pair of spectacles made of glass of light-violet color over dark-red glass, a combination which admits only red rays, so that most greens, for example, would appear black.