Source : Webster's Revised Unabridged Dictionary (1913)

Pyroscope \Pyr"o*scope\, n. [Pyro- + -scope: cf. F. pyroscope.]
   (Physics)
   An instrument for measuring the intensity of heat radiating
   from a fire, or the cooling influence of bodies. It is a
   differential thermometer, having one bulb coated with gold or
   silver leaf. [R.]

Source : WordNet®

pyroscope
     n : a pyrometer that uses the color of the light emitted by a
         hot object [syn: {optical pyrometer}]