Patent 1071952, sheet 1, showing diagrams for the "Recording apparatus for recording gas concentrations in the atmosphere". Patent granted October 7, 1952, for the patent application filed February 18, 1946.
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Beckman, Arnold Orville</div>
7 October 1952<div style="display: none;">date QS:P571,+1952-10-07T00:00:00Z/11</div>
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