The American Chemical Society designated the development of the Beckman pH meter a National Historic Chemical
Landmark on March 24, 2004. The plaque commemorating the event reads:
Arnold O. Beckman developed the first commercially successful electronic pH meter while a member of the faculty
of the California Institute of Technology. This rugged and portable "acidimeter," which had all necessary components
housed in a single unit, allowed scientists to measure acidity accurately and rapidly. It immediately met an
important need of the California citrus industry: how to measure the pH of lemon juice. The innovative features
of the pH meter, including an early use of integrated electronic technology, were the basis for subsequent modern
instrumentation developed by Beckman and Beckman Instruments.
In addition to the interviews cited in the text, the above discussion benefited greatly from several secondary sources,
but especially from the excellent biography by Arnold Thackray and Minor Myers Jr. Arnold O. Beckman: One Hundred Years
of Exellence. Philadelphia: Chemical Heritage Foundation, 2000.
Written by Judah Ginsberg
The author wishes to thank Mary Ellen Bowden, Paul Jones, and Frankie Wood-Black of the National Historic Chemical
Landmarks Committee for reading the text and correcting inaccuracies. He also wishes to than Dr. Stanley Pine of the
ACS Board of Directors for also reading the text. Needless to say, any errors are the author's alone.
Photo Credits: Pictures of acidimeter and Arnold Beckman holding an acidimeter are courtesy Beckman Coulter, Inc.
Designed by MSK Partners, Hunt Valley, Maryland.