Source : Webster's Revised Unabridged Dictionary (1913)

Melanoscope \Me*lan"o*scope\, n. [Gr. me`las, -anos, black +
   -scope.] (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.