Thermometer with wire extension photographed on March 17th, 1922
Thermometer with wire extension photographed on March 17th, 1922. Aided by the Directorate of Inventions, Charles Gorceix created a probe designed to gather thermometric readings when exploring lakes. His probe helped to seek out hot springs on the lakes’ floors, something other probing methods failed to perform. Gorceix’s device was made up of a fine wire wound around a copper mandrel through which water flowed. The temperature was discerned by evaluating the wire’s resistance using the Wheatstone bridge method. To eliminate interference from the cable, three of the bridge’s wires went down to the probe. The data was then read by a galvanoscope, suspended on three shock-absorbing springs. The wire was wound up on a winch, allowing it to descend to 145 meters, a depth equivalent to that of Lake Bourget. The device was described in the DRSII’s official gazette before being presented in a slightly improved, updated version. Office national des recherches scientifiques et industrielles et des inventions.