Thermoscope
Pronunciation : Ther"mo*scope
Part of Speech : n.
Etymology : [Thermo- + -scope.] (Physics)
Definition : Defn: An instrument for indicating changes of temperature without indicating the degree of heat by which it is affected; especially, an instrument contrived by Count Rumford which, as modified by Professor Leslie, was afterward called the differential thermometer.
Source : Webster's Unabridged Dictionary, 1913