Means for measuring air density and altitude at prevailing level of flight of an aircraft

Claim 1

THE COMBINATION COMPRISING AN ENCLOSURE, MEANS FOR SUPPLYING SAMPLED AMBIENT ATMOSPHERIC AIR TO WITHIN THE ENCLOSURE, A RADIUM IMPREGNATED MEMBER POSITIONED WITHIN SAID ENCLOSURE, SAID RADIUM IMPREGNATED MEMBER TO EMIT ALPHA, BETA AND GAMMA PARTICLES IN A FIXED RATIO FOR PASSAGE THROUGH SAMPLED ATMOSPHERIC AIR WITHIN THE ENCLOSURE, FIRST AND SECOND COUNTERS ADAPTED TO PROVIDE ELECTRICAL PULSES IN RESPONSE TO THE PARTICLES EMITTED FROM SAID MEMBER AND PASSING THROUGH THE AIR WITHIN THE ENCLOSURE, SAID PARTICLES BEING PARTIALLY ABSORBED BY THE AIR IN PROPORTION TO THE DENSITY THEREOF, THE FIRST OF SAID COUNTERS BEING RESPONSIVE TO ALPHA, BETA AND GAMMA PARTICLES, SAID FIRST COUNTER BEING POSITIONED IN SAID ENCLOSURE IN SPACED RELATION TO SAID RADIUM IMPREGNATED MEMBER AND AT ONE SIDE THEREOF, THE SECOND OF SAID COUNTERS BEING RESPONSIVE TO GAMMA PARTICLES, SAID SECOND COUNTER BEING POSITIONED IN SAID ENCLOSURE IN SPACED RELATION TO SAID RADIUM IMPREGNATED MEMBER AND AT ANOTHER SIDE THEREOF, MEANS BETWEEN SAID MEMBER AND SAID SECOND COUNTER TO PREVENT THE PASSAGE OF ALPHA AND BETA PARTICLES TO SAID SECOND COUNTER, MEANS TO SCATTER RADIATED PARTICLES FROM SAID MEMBERS THROUGH THE AIR IN SAID ENCLOSURE AND TOWARD SAID FIRST COUNTER, A PULSE INVERTER CONNECTED TO ONE OF SAID COUNTERS FOR INVERTING THE PULSES THEREFROM, INTEGRATING MEANS CONNECTED TO THE OTHER OF SAID COUNTERS, AND TO SAID INVERTER FOR PROVIDING A D.C. POTENTIAL CORRESPONDING TO THE PULSE DIFFERENCE FROM SAID COUNTERS, CURRENT CONTROL MEANS OPERATIVELY ASSOCIATED WITH SAID INTEGRATING MEANS AND CONTROLLED BY SAID D.C. POTENTIAL, MEANS FOR MEASURING ELECTRIC CURRENT, AN INDICATOR MEANS OPERATED BY SAID CURRENT MEASURING MEANS, MEANS OPERATIVELY CONNECTING SAID CONTROL MEANS TO SAID CURRENT MEASURING MEANS FOR CAUSING OPERATION OF THE CURRENT MEASURING MEANS AND THEREBY THE INDICATOR MEANS AS A FUNCTION OF THE DENSITY OF THE AIR IN SAID ENCLOSURE.