The Beckman pH Meter
"The pH meter was just a chance development that I did as a favor for Glen Joseph."1
In the mid-1930's Glen Joseph, a chemist at a research laboratory run by the California Fruit Growers Exchange,
paid a visit to his old college friend, Arnold Beckman, now an assistant professor of chemistry at the California
Institute of Technology. The Exchange controlled more than three-quarters of California's citrus output, and it
marketed its high quality fruit under the Sunkist label. Joseph sought Beckman's assistance in solving a problem
confronting California citrus growers: how to get an accurate and rapid measure of the acidity of lemon juice.
Joseph's request led to the invention of the Beckman pH meter which the American Chemical Society designated as a National
Historic Chemical Landmark at the California Institute of Technology in Pasadena, California, on March 24, 2004.
1 Arnold O.
Beckman, Interview by Jeffrey L. Sturchio and Arnold Thackray at University
of Pennsylvania, 23 July 1985 (Philadelphia: Chemical Heritage Foundation,
Oral History Transcript #0014B), p. 13.