Daniell Hygrometer
notes: label: Description
content: John Frederic Daniell, a young English natural philosopher, described this type of instrument in 1820. It consists of two glass balls, one partially filled with ether and the other covered with muslin, connected by a thin tube from which the air has been evacuated. There is a thermometer in the tube above the ball with the ether, and another on the supporting stand. When a few drops of ether are poured on the muslin, their evaporation chills the covered ball; that in turn causes the ether vapor inside the instrument to condense, thereby cooling the other ball and causing dew to form on its surface.
label: Description
content: The stand of this example is wood, marked "GERMANY" on the bottom. The white porcelain plate holding the interior thermometer is marked "Celsius" and graduated every degree from -25 to +50. The white porcelain plate holding the exterior thermometer is marked "CELSIUS" and graduated every degree from -10 to +50. There is a gold band around the lower bulb. It came to the Smithsonian from Cornell University.
label: Description
content: Ref: J. F. Daniell, "On a new Hygrometer, which Measures the Force and Weight of Aqueous Vapour in the Atmosphere, and the Corresponding Degree of Evaporation,"<i> Quarterly Journal of Science </i>8 (1820): 298-336.
label: Location
content: Currently not on view
place: label: place made
content: Germany
setName: label: See more items in
content: Medicine and Science: Physical Sciences
label: See more items in
content: Thermometers and Hygrometers
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content: Measuring & Mapping
creditLine: label: Credit Line
content: Cornell University
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.318271
label: catalog number
content: 318271
label: accession number
content: 231262
objectType: label: Object Name
content: Daniell hygrometer
physicalDescription: label: Measurements
content: overall: 26.4 cm x 20.3 cm; 10 13/32 in x 8 in
label: Measurements
content: overall: 10 1/4 in x 8 in x 4 in; 26.035 cm x 20.32 cm x 10.16 cm