Controls for electrical instruments

Claim 1

FOR USE IN CAMERAS, IN COMBINATION, A GALVANOMETER HAVING A ROTOR ADAPTED TO TURN IN RESPONSE TO CHANGES IN LIGHT INTENSITY AND HAVING AN ELONGATED POINTER FIXED TO AND EXTENDING RADIALLY FROM SAID ROTOR FOR TURNING MOVEMENT THEREWITH; A FIRST PERMANENT MAGNET CARRIED BY SAID POINTER AT A SUBSTANTIAL DISTANCE FROM THE TURNING AXIS OF SAID ROTOR SO THAT SAID FIRST PERMANENT MAGNET TURNS WITH SAID POINTER THROUGH A SUBSTANTIAL DISTANCE EVEN WHEN SAID POINTER THROUGH A SUBSTANTIAL DISTANCE ANGLE; A SECOND PERMANENT MAGNET; MEANS MOUNTING SAID SECOND PERMANENT MAGNET SUBSTANTIALLY IN THE PATH OF TURNING OF SAID FIRST PERMANENT MAGNET WHEN THE LATTER TURNS WITH SAID POINTER DURING AN INCREASE IN LIGHT INTENSITY SO THAT DURING ROTATION OF SAID ROTOR WHEN THE LIGHT INTENSITY INCREASES SAID FIRST PERMANENT MAGNET APPROACHES SAID SECOND PERMANENT MAGNET, AND SAID MAGNETS RESPECTIVELY HAVING LIKE POLES DIRECTED TOWARD EACH OTHER SO THAT SAID MAGNETS COOPERATE TO REDUCE THE EXTENT TO WHICH SAID ROTOR TURNS DURING INCREASES IN LIGHT INTENSITY; AND A DIAPHRAGM BLADE ALSO FIXED TO SAID ROTOR FOR TURNING MOVEMENT THEREWITH AND COOPERATING WITH AN OBJECTIVE OF THE CAMERA TO PARTICIPATE IN THE CONTROL OF THE EXPOSURE APERTURE THROUGH SAID OBJECTIVE, SAID DIAPHRAGM BLADE EXTENDING FROM SAID ROTOR IN A DIRECTION SUBSTANTIALLY OPPOSED TO THE DIRECTION IN WHICH SAID POINTER EXTENDS.