pH Meter
name: label: maker
content: Coleman Electric Company
notes: label: Description
content: A pH meter measures the acidity of aqueous solutions. The first modern example was designed in the 1930s by the chemist, Arnold Beckman. This example was used at the National Bureau of Standards. The inscription on a metal label reads “Instrument No. 3787 / Model 3D / COLEMAN ELECTRIC CO., INC. / Pat. Pend. / Maywood, Ill.” The dial reads “MILLIAMPERES D.C.” and “COLEMAN Electric Company / Maywood, ILL. / U.S.A.”
label: Description
content: The Coleman Electric Company, established by Edwin Dewitt Coleman in the 1930s, made “precision tools for the technologist” during World War II, and became Coleman Instruments in the 1940s. Coleman submitted his patent application for this instrument in January 1939
label: Description
content: Ref: Edwin D. Coleman, “pH Measurement and Control Device,” U.S. Patent 2,311,976 (Feb. 23, 1943).
label: Location
content: Currently not on view
place: label: place made
content: United States
setName: label: See more items in
content: Medicine and Science: Chemistry
creditLine: label: Credit Line
content: Transfer from Excess Property, National Bureau of Standards
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: CH.326626
label: catalog number
content: 326626
label: accession number
content: 261654
objectType: label: Object Name
content: pH Meter
physicalDescription: label: Measurements
content: battery 1: 4 in x 2 1/2 in x 2 1/2 in; 10.16 cm x 6.35 cm x 6.35 cm
label: Measurements
content: battery 3: 10.5575 cm x 13.1763 cm x 3.3338 cm; 4 3/16 in x 5 3/16 in x 1 5/16 in
label: Measurements
content: case: 26.6 cm x 30.5 cm x 19 cm; 10 1/2 in x 12 in x 7 1/2 in
label: Measurements
content: overall in case: 10 7/8 in x 11 7/8 in x 7 3/8 in; 27.6225 cm x 30.1625 cm x 18.7325 cm