General view of an employee in the Bureau of Chemistry's Water and Beverage Laboratory conducting an analysis on an unidentified substance. Assorted sample jars and scientific apparatus are visible in the photograph.…

General view of employee W. Crocker at work in the factory control work area of the Dearborn Chemical Company's 35th Street Laboratory facility and manufacturing plant. Per notations accompanying the photograph,…

General view of assorted water samples sent to the Dearborn Chemical Company's 35th Street Laboratory for analysis. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of BetzDearborn, Incorporated…

General view of two unidentified men utilizing a Dearborn Chemical Company portable testing cabinet to conduct a water sample field test. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of…

General view of Dearborn Chemical Company employee E.P. Fager comparing the color of two solutions during a water sample field test. Assorted glassware and a Dearborn portable testing cabinet are visible on the table.…

General view of Dearborn Chemical Company employee E.P. Fager preparing a water sample for testing. A stamp on the verso of the photograph for "The Fensholt Company," a public relations firm based in Chicago, suggests…

General view of Dearborn Chemical Company engineer F.B. Horstmann utilizing a portable testing cabinet to conduct a water sample field test. A stamp on the verso of the photograph for "The Fensholt Company," a public…

General view of Dearborn Chemical Company employee C.B. Smith utilizing a concentration hydrometer during a water sample field test. Assorted glassware and a Dearborn portable testing cabinet are also visible on the…

General view of several employees conducting water analysis tests at the Dearborn Chemical Company's 35th Street laboratory and manufacturing facility located in Chicago, Illinois. The three employees visible in the…

General view of employee Al Slisg conducting a water analysis test at the Dearborn Chemical Company's 35th Street laboratory and manufacturing facility located in Chicago, Illinois. Founded in 1887, the Dearborn…

General view of assorted water samples sent to the Dearborn Chemical Company's 35th Street Laboratory for analysis. Founded in 1887, the Dearborn Chemical Company was a corporate ancestor of BetzDearborn, Incorporated…

General view of employee E.L. Konigsmark recording water samples sent to the Dearborn Chemical Company's 35th Street Laboratory facility and manufacturing plant for analysis. Founded in 1887, the Dearborn Chemical…

General view of employees (left to right) Ray Shoan, Charles S. White, Andrew Lombardi, and Bernard Tarley conducting water analysis tests at the Dearborn Chemical Company's 35th Street laboratory and manufacturing…

General view of Dearborn Chemical Company representative C.M. Kesler (seated) and hospital employee "Mike" examining a sample of water at Mary's Help Hospital (now Seton Medical Center) in San Francisco, California. Per…

General view of an unidentified employee preparing a water sample for testing at a Dearborn Chemical Company's laboratory facility in Chicago, Illinois. A stamp on the verso of the photograph for "The Fensholt Company,"…

Procedures for a series of tests used in water analysis. The experiments include the determination of various minerals and contaminants present in water samples such as nitrite, sulfates, iron, etc. Each contains a list…

General view of laboratory technician Richard Thomson preparing water samples for testing at the New York City Bureau of Water Supply's Ben Nesin Laboratory. Per notations accompanying the photograph, a Perkin-Elmer…

General view of a Perkin-Elmer Atomic Absorption Spectrophotometer in use at a Calgon Water Management laboratory facility. Per notations accompanying the photograph, the spectrophotometer is equipped with a…

General view of employee Jack Guillaumin (right) and an unidentified chemist reviewing the results of an analysis conducted by a Perkin-Elmer Model 306 Atomic Absorption Spectrophotometer in a laboratory at the Detroit…

General view of an unidentified chemist operating a Perkin-Elmer gas chromatograph in an Environmental Protection Agency (EPA) Region II laboratory located in Edison, New Jersey. Per notations accompanying the…

General view of a Perkin-Elmer Grating Infrared Spectrophotometer in use at a Calgon Water Management laboratory facility. Per notations accompanying the photograph, the spectrophotometer is being used to characterize…

General view of a Perkin-Elmer Model 337 Grating Infrared Spectrophotometer in use at a Calgon Water Management laboratory facility. The female technician visible in the photograph is unidentified.

General view of an unidentified employee operating a Perkin-Elmer Atomic Absorption Spectrophotometer with a heated graphite atomizer (HGA) attachment in use at a Calgon Water Management laboratory facility. Per…

General view of an unidentified female employee pouring a water sample into the tray of a Perkin-Elmer Autosampler at an Environmental Protection Agency (EPA) laboratory facility located in Edison, New Jersey. Per…

General view of Wilson Walker, Chief Chemist at the Ohio Department of Health's Sanitary Chemistry Laboratory, injecting a sample of drinking water into the cylinder of a Perkin-Elmer Heated Graphite Atomizer (HGA). Per…