- A pH meter measures the acidity of aqueous solutions. When asked about a meter suitable for testing citrus fruit, Arnold Beckman, a young chemist at the California Institute of Technology, designed one with glass electrodes, and introduced a prototype at the American Chemical Society meeting in 1935. Most instrument dealers were deterred by the cost (about $195), but with encouragement from Arthur H. Thomas, in Philadelphia, Beckman established the National Technical Laboratories in Pasadena, and began production. The firm became Arnold O. Beckman, Inc. in the 1940s, and later Beckman Instruments, Inc.
- This example came from the National Bureau of Standards. The inscription on a metal tag reads “A. Beckman Instrument Patents Issued and Pending Serial No. 5956 Model G Manufactured in U.S.A. by National Technical Laboratories – South Pasadena, Calif.” The Model G was introduced in 1937.
- Currently not on view
- Object Name
- pH Meter
- National Technical Laboratories
- battery 3: 2 3/4 in x 4 in x 7/8 in; 6.985 cm x 10.16 cm x 2.2225 cm
- box: 28 cm x 28.5 cm x 21.5 cm; 11 in x 11 1/4 in x 8 7/16 in
- battery 1: 4 in x 2 5/8 in x 2 5/8 in; 10.16 cm x 6.6675 cm x 6.6675 cm
- overall in box: 11 1/2 in x 11 1/4 in x 8 1/4 in; 29.21 cm x 28.575 cm x 20.955 cm
- ID Number
- catalog number
- accession number
- Credit Line
- Transfer from Excess Property, National Bureau of Standards
- See more items in
- Medicine and Science: Chemistry
- Data Source
- National Museum of American History
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