Recording direction finder for bursts of radiation

Claim 1

A ROCORDING DIRECTION FINDER OF FLASHES EMITTING BURSTS OF RADIANT LIGHT AND HEAT, COMPRISING AN UPRIGHT HOLLOW CYLINDRICAL SHEET METAL CASING, HAVING PERFORATIONS THROUGH ITS WALL EVENLY SPACED AROUND IT NEAR ITS UPPER END, EACH ADMITTING LIGHT FROM AN ARC IN AZIMUTH, SAID ARCS OVERLAPPING, GROOVES GUIDEWAYS ON THE INNER SURFACE OF SAID CASING MIDWAY BETWEEN SAID PERFORATIONS, ONE ONLY OF SAID GUIDEWAYS BEING GROOVED THROUGH A PART ONLY OF ITS LENGTH, A DOMED PLATE CLOSING THE TOP OF SAID CASING AND HAVING AN INDICATION OF DIRECTIN UPON IT, A SHEET METAL DISC ADAPTED TO CLOSE THE LOWER END OF SAID CASING, PART-CYLINDRICAL SCREEN SECURED TO SAID DISC WITH THEIR CONCAVITIES FACING OUTWARD AND THEIR NEIGHBOURING STRAIGHT EDGES JOINED, ONE PAIR ONLY OF SAID JOINED EDGES BEING CUT BACK OVER PART OF ITS LENGTH, SAID JOINED EDGES ENTERING THE GROOVED GUIDEWAYS OF THE CASING AND THE AXES OF SAID PART CYLINDER LYING IN THE WALL OF SAID CASING AND PASSING THROUGH THE RESPECTIVE PERFORATIONS THEREIN, LIGHTSENSITISED SHEET GRADUATED IN AZIMUTH LINING SAID PART CYLINDERS, AND MEANS FOR SECURING SAID CASING AND DISC TO A FIXED AMOUNTING WITH SAID INDICATING OF DIRECTION IN A DETERMINED AZIMUTHAL SETTING.