Photometric apparatus

Claim 1

IN A PHOTOMETRIC APPARATUS COMPRISING AN INTEGRATING SPHERE HAVING A FIRST AND SECOND PORT FOR THE INSERTION OF SAMPLE, A PHOTOTUBE ADJACENT TO ANOTHER PORT IN THE INTEGRATING SPHERE, MEANS FOR GENERATING A LIGHT BEAM, INSERTED IN THE SAID LIGHT BEAM A POLARIZER AND AN ANALYZER SET TO EXTINGUISH THE POLARIZED AND AN DIVIDING THE SAID LIGHT BEAM INTO TWO BEAMS DIRECTED AT THE SAID SAMPLE PORTS IN THE INTEGRATING SPHERE, MEANS FOR AMPLIFYING SIGNALS GENERATED BY THE SAID PHOTOTUBE, A REED ADAPTED TO VIBRATE BY ELECTRICAL IMPULSES, A VANE MOUNTED ON THE REED OBSTRUCTING EQUAL PORTIONS OF THE SAID BEAMS WHEN AT REST AND EQUAL ALTERNATE PORTIONS WHEN VIBRATING, THE IMPROVEMENT COMPRISING A LIGHT MODULATOR INSERTED IN THE PATH OF LIGHT BETWEEN THE SAID POLARIZER AND ANALYZER, THE SAID LIGHT MODULATOR CONSISTING OF A PHOTOELASTIC BODY ARRANGED BETWEEN TWO ELECTROMAGNETS WHICH ARE ACTUATED BY A CURRENT OF UNIFORM VOLTAGE TO EXERT A STRESS UPON THE PHOTOELASTIC BODY WHICH IS ABOUT EQUAL IN EFFECT TO TURNING THE ANALYZER FROM TOTAL EXTINCTION OF THE LIGHT TO ONE-HALF EXTINCTION, AND A MODULATING COIL WOUND ABOUT AT LEAST ONE OF THE ELECTROMAGNETS SO AS TO INCREASE THE STRESS UPON THE PHOTOELASTIC BODY IN ACCORD WITH AMPLIFIED SIGNALS GENERATED BY THE PHOTOTUBE DUE TO THE INTENSITY OF THE LIGHT RECEIVED BY THE PHOTOTUBE FROM ONE SAMPLE BEING LOWER THAN THE INTENSITY OF THE LIGHT RECEIVED FROM THE OTHER SAMPLE, AND MEANS FOR FEEDING SUCH AMPLIFIED SIGNALS TO THE SAID MODULATING COIL.