Daniell Hygrometer
notes: label: Description
content: John Frederic Daniell, a young English natural philosopher, described this form 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: This example has a wood stand. The interior thermometer is mounted on a white porcelain plate that is graduated every degree C. from -9 to +50 and every two degrees F. from -24 +120. The exterior thermometer is mounted on a brass plate that is graduated every degree C. from -10 to +50 and every two degrees F. from +20 to +121. There is a gold band around the equator of the lower bulb.
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
setName: label: See more items in
content: Medicine and Science: Physical Sciences
creditLine: label: Credit Line
content: Gift of Trenton State University
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1982.0230.10
label: accession number
content: 1982.0230
label: catalog number
content: 1982.0230.10
objectType: label: Object Name
content: hygrometer
physicalDescription: label: Measurements
content: overall: 12 in x 8 1/4 in x 5 in; 30.48 cm x 20.955 cm x 12.7 cm