Photographs of images from an album containing pictures of chemist Arnold O. Beckman and his wife, and Mabel Meinzer Beckman, taken during their courtship and the early years of their marriage. Images include Arnold O.…

Arnold O. Beckman at a Delta Upsilon party during his time at the University of Illinois, 1918-1923.

Dr. Arnold O. Beckman (1900-2004) invented the first commercially successful electric pH meter in 1934 and thus began…

This image is from the Beckman Historical Collection, although the relationship between Republic Flow Meters Company and Beckman Instruments is unclear.

The McLeod Gauge measures very low pressures of gasses. Its presence in this collection indicates that it was used during the production of Beckman Instruments' early pH meters. These calibrations may have been written…

This garage was the first location of the National Inking Appliance Company, founded by the National Postal Meter Company in 1934 to manufacture the new, nonclogging inking device invented by Arnold O. Beckman. This…

In this letter, Lee de Forest requests a referral to a chemist who might help electroplate film.

Lee de Forest (1873–1961) was an inventor, most notably of Audion vacuum tubes in the early twentieth century. His serial…

Arnold O. Beckman, then an assistant professor of chemistry at Caltech, offers his assistance as a consulting chemist.

Lee de Forest (1873–1961) was an inventor, most notably of Audion vacuum tubes in the early…

Arnold O. Beckman applied (ultimately unsuccessfully) for a job at E. I. du Pont de Nemours and Company. The letter includes details of his work experience, publications, and educational background, including a…

The handwritten document was created in connection with Arnold O. Beckman's consulting work for Lee de Forest.

The letter requests deliverables of 100 feet of silvered film, and two 10 foot pieces with a silver coating on emulsion film and clear stock.

Lee de Forest (1873–1961) was an inventor, most notably of Audion vacuum…

The letter discusses the "very nice results" of using new Eastman film and queries as to the possible effects of light upon silvering solution.

Lee de Forest (1873–1961) was an inventor, most notably of Audion vacuum…

De Forest inquires about Beckman's progress toward a chemical coating that might change in opacity or color, and details the "very fine and uniform quality" of silver coated film de Forest is able to produce.

Lee de…

In this letter, de Forest proposes a process that could replace halftone film.

Lee de Forest (1873–1961) was an inventor, most notably of Audion vacuum tubes in the early twentieth century. His serial business ventures…

Glenn Joseph writes to Dr. Beckman about the process of finding the right buffer to use in the new glass electrodes inside the pH meter. The identify of the "Dr. Dupont" referenced in this letter is uncertain.

Arnold…

In this letter, Glenn Joseph reports that the vacuum-tube amplifier in the early Beckman pH meter model is (still) not functioning properly. One of the fixes he proposes is replacing the vacuum tubes with a glass…

A Pasadena garage was the first home of the National Postal Meter Company, founded by Arnold Beckman in 1934. The company soon became National Technical Laboratories, with a focus on pH meters. In 1935, the company…

This job schedule is a snapshot of the work being done by NTL in January, 1934. This work included the important pH meter development for the California Fruit Growers Exchange, of course, but also a project for Lee de…

These calibrations and the diagram were done by W. E. Baier, Research Manager of the California Fruit Growers' Exchange. The McLeod Gauge measures very low pressures of gasses. Its presence in this collection indicates…

Directions for calibrating a McLeod gauge for use with the early model of the Beckman pH meter. This letter is likely related to the handwritten McLeod gauge diagrams and calculations also found in this folder. At the…

Invoice from Arnold O. Beckman to W. E. Baier
for developing and calibrating McLeod gauges and glass electrodes -- components involved in the early Beckman pH meter.

Arnold Beckman invented his first pH meter in 1934…

In this letter, de Forest discusses the possibility of using chemicals to fight forest fires.

Lee de Forest (1873–1961) was an inventor, most notably of Audion vacuum tubes in the early twentieth century. His serial…

Arnold O. Beckman provides an overview of the vacuum film-coating process developed for Lee de Forest. The process successfully coated film with magnesium, lead, bismuth, aluminum, and silver. The letter is apparently…

A bill sent by Arnold Beckman to W. E. Baier, covering the cost of a "glass-electrode apparatus," which was included in the first Beckman pH meter.

Arnold Beckman invented his first pH meter in 1934 at the request of a…

This letter spells out the instrument maintenance and upgrades that the California Fruit Growers Exchange believe are included with the cost of developing the "glass electrode apparatus" (an early prototype of the…