1. IN A SYSTEM FOR INDICATING MOTION, IN COMBINATION, A SUPPORTING STRUCTURE ROTATABLE AT HIGH VELOCITY ABOUT AN AXIS NORMAL TO A COMPONENT OF AN ACCELERATION TO BE INDICATED; A PAIR OF MASSES CARRIED BY SAID STRUCTURE AND DISPOSED ON OPPOSITE SIDES OF SAID AXIS; MOUNTING MEANS JOINING SAID MASSES TO SAID STRUCTURE WITH THE FREEDOM MEANS LIMITED RADIAL DISPLACEMENT TOWARDS AND AWAY FROM SAID AXIS; SPRING MEANS RESTRAINING SUCH DISPLACEMENT WHEREBY SAID MASSES WILL UNDERGO OSCILLATORY MOVEMENTS IN RESPONSE TO SAID ACCELERATION ABOUT MEAN POSITIONS OF EQUILIBRIUM DETERMINED BY THE MUTUALLY OPPOSING ACTIONS OF SAID SPRING MEANS THE CENTRIFUGAL FORCE INDUCED BY SAID VELOCITY; ELECTRIC CIRCUIT MEANS INCLUDING CAPACITIVE PICK-OFF MEANS ASSOCIATED WITH EACH MASS AND SAID STRUCTURE FOR CONVERTING SAID OSCILLATORY MOVEMENT INTO FLUCTUATING CAPACITANCES; FIRST AND SECOND OSCILLATOR MEANS CONNECTED TO SAID PICK-OFF MEANS FOR RESPECTIVELY GENERATING A FIRST AND A SECOND OSCILLATORY ELECTRIC SIGNALS FRE-