Reference half-cell

Claim 1

A REFERENCE HALF-CELL FOR MEASURING ELECTRIC POTENTIALS COMPRISING AT LEAST ONE ELECTRODE AND AN IMMOBILIZED ELECTROLYTE AT LEAST PARTIALLY COMPOSED OF A SALT OF SAID ELECTRODE MATERIAL, SAID ELECTRODE AND SAID ELECTROLYTE BEING IN PHYSICAL CONTACT AND BEING ENCASED IN A SUBSTANTIALLY IMPERVIOUS, INSULATING, BREAK-RESISTANT CONTAINER, SAID CONTAINER HAVING CONDUIT MEANS EXTENDING THERETHROUGH FILLED WITH ADDITIONAL IMMOBILIZED ELECTROLYTE WHICH ADDITIONAL ELECTROLYTE IS IN ELECTRICAL CONTACT WITH SAID ELECTROLYTE AND WHICH ADDITIONAL ELECTROLYTE IS EXPOSED THROUGH SAID CONDUIT MEANS AT A POINT EXTERNAL TO SAID CONTAINER, SAID EXPOSED ADDITIONAL IMMOBILIZED ELECTROLYTE FORMING A SALT BRIDGE FOR CONTACTING A MATERIAL, THE ELECTRIC POTENTIAL OF WHICH IS SOUGHT, SAID ELECTRODE AND SAID ELECTROLYTE EACH BEING ATTACHED TO SEPARATE CONDUCTIVE CONNECTIONS, SAID HALF-CELL BEING CHARACTERIZED BY ITS SUBSTANTIALLY CONSTANT REFERENCE POTENTIAL, LOW TEMPERATURE COEFFICIENT OF VOLTAGE, CORROSION RESISTANCE AND BY ITS ABILITY TO AVOID DIFFUSION OF ELECTROLYTE CONTAINING A SALT OF A METAL WHICH WILL PLATE OUT ON SAID MATERIAL.