Cymoscope

Cy´mo`scope

n.

1.

(Elec.) Any device for detecting the presence of electric waves. The influence of electric waves on the resistance of a particular kind of electric circuit, on the magnetization of steel, on the polarization of an electrolytic cell, or on the electric condition of a vacuum has been applied in the various cymoscopes.

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.