Method and means using thermoelectric comparison for identifying conductive materials

Claim 1

A METALS CLASSIFIER COMPRISING A HOUSING, A PAIR OF LEGS SUPPORTED FROM SAID HOUSING AND PROVIDING FIRST AND SECOND POINTS OF CONTACT WITH AN UNKNOWN, A STANDARD INDICATING CIRCUIT INCLUDING DISSIMILAR STANDARD CONDUCTORS EXTENDING THROUGH BOTH SAID LEGS AND HAVING A PLURALITY OF THERMOCOUPLE JUNCTIONS, ONE SAID JUNCTION AT ONE SAID CONTACT POINT, MEANS FOR UNIFORM DIFFERENTIAL HEATING OF SAID ONE THERMOCOUPLE JUNCTION, MEANS FOR INDICATING THE POTENTIAL INDUCED IN SAID CIRCUIT BY SAID DIFFERENTIAL HEATING, AN UNKOWN READING CIRCUIT INCLUDING SAID POTENTIAL RESPONSIVE MEANS AND MEANS FOR CONNECTING THAT TO THE OTHER SAID CONTACT AND THEREBY COMPLETING A CIRCUIT THROUGH AN UNKNOWN APPLIED TO BOTH SAID POINTS OF CONTACT, AND MEANS MANIPULABLE SELECTIVELY TO INCLUDE ONE OR ANOTHER OF SAID DISSIMILAR CONDUCTORS IN SAID UNKNOWN READING CIRCUIT.