Dictionary entry

Thermophone

Webster's Dictionary 1913

Ther″mo‐phone (?), n. [Thermo- + phone.] 1. A portable form of telethermometer, using a telephone in connection with a differential thermometer.

2. A telephone involving heat effects, as changes in temperature (hence in length) due to pulsations of the line current in a fine wire connected with the receiver diaphragm.