Handwritten and -drawn notes detail the resistors used in the Model F pH meter.
Arnold Beckman invented his first pH meter in 1934 at the request of a chemist from the California citrus industry, who needed an accurate…
This series of handwritten and -drawn notes relates to the development of the Beckman DU-X2 spectrophotometer. One of the pages appears to be missing.
The first Beckman Instruments DU Spectrophotometer was developed in…