The diagram is annotated in red and blue ink, indicating first and second position.

Arnold Beckman invented his first pH meter in 1934 at the request of a chemist from the California citrus industry, who needed an…

In this letter, J. H. Rushton of the National Defense Research Committee requests an update on the status of F and G model oxygen meter instruments.

Developed from a Linus Pauling design during WWII, the technology…

In this letter, Dr. Prentiss inquires about the possibility of combining a moisture detector and an oxygen meter, presumably for use in submarines. At the time, Dr. Spencer S. Prentiss was working for the National…

Letter inquiring about the price and delivery of model P and A Pauling Oxygen Meters for use by the National Defense Research Committee. This letter was originally sent to Dr. Beckman with another letter from Spencer…

The Beckman Instruments IR spectrophotometers began as a request from the Office of Rubber Reserve to Arnold O. Beckman in 1942, asking for an infrared spectrophotometer that they could use to create rubber. Under this…

Letter regarding the extension of the military contract for Beckman Instruments' Pauling Oxygen Meter development. This letter also mentions the possibility of using the instrument inside oxygen tents.

Developed from a…

The Beckman Instruments IR spectrophotometers began as a request from the Office of Rubber Reserve to Arnold O. Beckman in 1942, asking for an infrared spectrophotometer that they could use to create rubber. Under this…

Arnold Beckman informs J. H. Rushton that the Model G oxygen meter is ready for testing, but the Model F is not. An order has been received from the Linde Company, but not fulfilled, and an experimental instrument was…

This letter regards the use of oxygen meters on submarines and in hospitals, issues of cost and portability, and the Naval Research Laboratory's interest in detecting other gases.

Developed from a Linus Pauling design…

The letter regards the procurement of Pauling meters for use on submarines and issues of cost and portability.

Developed from a Linus Pauling design during WWII, the technology behind Beckman Instruments’ oxygen…

Request from the National Defense Research Committee for a Model L Pauling Oxygen Meter to test at high altitudes in airplanes.

Developed from a Linus Pauling design during WWII, the technology behind Beckman…

The letter discusses the various parties interested in testing Pauling oxygen meters and the possibility of meeting in Washington or Philadelphia.

Developed from a Linus Pauling design during WWII, the technology…

The letter sketches the specifications for a partial pressure indicator for use in aircraft, and notes that a prototype has already been constructed. The recipient may be a member of the Navy's Research and Development…

In this letter, Beckman requested permission to discuss the Pauling Oxygen Meter and made the case that the National Defense Research Committee (NDRC) should lift the "Restricted" classification.

In this letter, Churchill confirms that the National Defense Research Committee (NDRC) has granted Beckman permission to discuss the Pauling Oxygen Meter at an American Chemical Society meeting.

Letter regarding the possible development of an aviation model of the Pauling Oxygen Meter for the Bureau of Aeronautics.

Developed from a Linus Pauling design during WWII, the technology behind Beckman Instruments’…

Linus Pauling's oxygen meter was developed as a military project and the details were classified. In this letter, Pauling requested permission to discuss the oxygen meter at a Caltech seminar. He also states a desire to…

In this letter Pauling reiterates requests for permission to discuss and publish on the oxygen meter, and argues for loosening security classification. He cites Arnold O. Beckman's permission to discuss the project…

Arnold Beckman expresses concern that the secrecy of the oxygen meter project could adversely affect sales in the anticipated post-war markets.

Developed from a Linus Pauling design during WWII, the technology behind…

In this letter, Beckman describes the specifications of the aircraft model oxygen meter (the Model L).

Developed from a Linus Pauling design during WWII, the technology behind Beckman Instruments’ oxygen analyzers…

The letter discusses testing of the Pauling hospital oxygen meter and concerns about its ruggedness--specifically, its ability to survive being dropped onto a stone floor from a height of three feet.

Developed from a…

In this letter, Prentiss shares his initial impressions of a prototype aircraft oxygen meter.

Developed from a Linus Pauling design during WWII, the technology behind Beckman Instruments’ oxygen analyzers ended up…

Summarizing a report of the Army Medical Center's trial of the Pauling oxygen meter, Julius Kauffman noted that the device was accurate but "rather fragile."

Developed from a Linus Pauling design during WWII, the…

Letter summarizes the final report produced by testing the Pauling Oxygen Meter at the Army Medical Center. The final recommendation of the report is that this oxygen meter should not be standardized for use by the U.S.…

Prentiss responds to Kauffman's assessment of the hospital oxygen analyzer, with emphasis upon the question of its ruggedness.

Developed from a Linus Pauling design during WWII, the technology behind Beckman…