Negretti & Zambra Minimum Thermometer

This alcohol-in-glass Rutherford-type thermometer is mounted on a white porcelain plate marked "NEGRETTI & ZAMBRA, SCIENTIFIC INST. MAKERS, LONDON" with the N/Z monogram of the firm, and "24" with the M/O monogram of the British Meteorological Office. This plate is graduated every 5 degrees Fahrenheit from -20 to +110. The stem is marked "24" and with the N/Z and M/O monograms; and is graduated (but not numbered) every degree F. from -21 to +112. The whole is mounted on a wooden base with metal guards for the bulb. There are also two metal loops so that it can be hung horizontally. It came to the Smithsonian from the U.S. Weather Bureau.
Negretti & Zambra claimed that they were "the first to introduce into extensive use thermometer and barometer scale-plates made of porcelain, having the divisions and figures engraved thereon by means of fluoric acid, and permanently burnt-in and blackened so as always to present a clear legible scale" that would not be affected by sea water or by atmospheric conditions.
Ref.: Negretti & Zambra, A Treatise on Meteorological Instruments (London, 1864), pp. 65 and 76.
Currently not on view
Object Name
minimum thermometer
date made
after 1850
Negretti & Zambra
overall: 11 11/32 in; 28.829 cm
place made
United Kingdom: England, London
ID Number
accession number
catalog number
Measuring & Mapping
Thermometers and Hygrometers
See more items in
Medicine and Science: Physical Sciences
Thermometers and Hygrometers
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
U.S. Weather Bureau

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