Electrical measuring systems

Claim 1

IN APPARATUS FOR MEASURING THE DIELECTRIC CONSTANT OF A SUBSTANCE, THE COMBINATION COMPRISING A TEST CELL INCLUDING A PAIR OF ELECTRODES SPACED TO RECEIVE A SUBSTANCE THEREBETWEEN, A VARIABLE CAPACITOR, CAPACITATIVE MEANS CONNECTED IN PARALLEL WITH SAID VARIABLE CAPACITOR AND SAID TEST CELL FOR INCREASING THE CAPACITANCE OF EACH OF SAID VARIABLE CAPACITOR AND SAID TEST CELL BY A FIXED AMOUNT, SAID FIXED AMOUNT BEING GREATER THAN THE CAPACITANCE OF SAID TEST CELL, MEANS FOR PASSING ALTERNATING CURRENT THROUGH SAID TEST CELL AND SAID VARIABLE CAPACITOR FOR PRODUCING POTENTIALS THEREACROSS, MEANS RESPONSIVE TO THE DIFFERENCE IN POTENTIALS ACROSS SAID TEST CAPACITOR AND SAID VARIABLE CAPACITOR FOR ADJUSTING THE CAPACITANCE OF SAID VARIABLE CAPACITOR SUBSTANTIALLY TO EQUALIZE THE RESULTANT POTENTIALS ACROSS SAID TEST CELL AND SAID VARIABLE CAPACITOR, AND MEANS RESPONSIVE TO THE ADJUSTMENT OF SAID VARIABLE CAPACITOR FOR PROVIDING AN INDICATION WHICH IS A FUNCTION OF THE DIELECTRIC CONSTANT OF SAID SUBSTANCE.