Winlock and Huddleston Psychrometer

Joseph Winlock, a professor of astronomy at Harvard, and John S. F. Huddleston, a thermometer and barometer maker in Boston, designed this instrument to provide "a simple, efficient, and convenient means of determining the relative humidity of the atmosphere or the dew-point, so called, without calculation."
In this example, the dry bulb thermometer is mounted on a plate that is marked "HYGROPHANT" and "PATENTED MARCH 31, 1874" and and "805" and graduated every degree Fahrenheit from -30 to +125. The wet bulb thermometer is mounted on a plate that is marked "HUDDLESTON BOSTON" and graduated every degree Fahrenheit from -10 to +125. Between the two is a rotating chart that indicates relative humidity, as well as a plate graduated every degree from 0 to +110.
Ref: J. Winlock and J. S. F. Huddleston, "Psychrometer," U.S. Patent 149176 (1874).
Currently not on view
Object Name
Huddleston, John S. F.
Winlock, Joseph
place made
United States: Massachusetts, Boston
ID Number
catalog number
accession number
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Thermometers and Hygrometers
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Smithsonian Astrophysical Observatory

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