cummings

Claim 1

IN A METHOD FOR DETERMINING THE INTENSITY OF IRRADIATION AT A SELECTED POINT WITHIN A CONTAINER WHICH IS SYMMETRICAL ABOUT AN AXIS, SAID POINT BEING IN AN INVESTIGATION PLANE PERPENDICULAR TO SAID AXIS, WHEN SAME IS SUBJECTED TO IRRADIATION BY A PLURALITY OF BEAMS OF PREDETERMINED STRENGTH AND IMPOSED FROM SELECTED DIRECTIONS IN A COMMON PLANE WHICH IS PERPENDICULAR TO SAID AXIS AND WHEN A PATTERN OF RADIATION INTENSITY IS KNOWN FOR ONE SUCH BEAM WHEN SAME IS PROJECTED ONTO SAID CONTAINER FROM A SINGLE DIRECTION WITHIN SAID PLANE, THE STEPS COMPRISING: ARRANGING MIXTURES OF BLACK AND WHITE COLORING MATERIAL ON A PANEL IN BANDS CORRESPONDING TO THE STRENGTH OF IRRADIATION FROM SAID SINGLE DIRECTION ON SAID INVESTIGATION PLANE WITHIN SAID CONTAINER WHEREIN THE BLACK COLORING MATERIAL USED IN EACH BAND BEARS TO THE TOTAL MIXTURE THE SAME PERCENTAGE VALUE AS THE ACTUAL IRRADIATION AT THE CORRESPONDING PART OF SAID CONTAINER BEARS TO THE MAXIMUM VALUE OF IRRADIATION; ROTATING SAID PANEL IN ITS PLANE SUFFICIENTLY RAPIDLY AS TO MAKE A COMPLETE ROTATION WITHIN THE NORMAL PERIOD OF HUMAN EYE RETENTIVITY; ILLUMINATING SAID PANEL AND VISUALLY MEASURING THE APPARENT GREY DENSITY AT A SELECTED POINT ON THE ROTATING PANEL.