Horizontal Pedestal Sundial - Cannon Dial
date: label: date made
content: 1800-1860
notes: label: Description
content: This cannon sundial consists of a round marble base, two brass supports for a magnifying glass, and a brass cannon. A dial calibrated from 7 to 12 to 5 by 1 for a latitude of 43 degrees is carved into the marble base. A hole within the dial held a blade gnomon for indicating the local time. The gnomon for this dial is missing. One of the supports for the magnifying glass is calibrated with the months of the year. Knurled thumb screws in each of the supports allow the hinged magnifying glass to be adjusted for the calendar date so that the rays of the sun would be focused onto the touch hole of the cannon. At local apparent noon, the sun rays would ignite a few grains of black powder and cause the gun to fire. Victor Chevalier (1770-1841), a Parisian instrument maker, has been credited with patenting the cannon sundial. This particular instrument dates to the 1800s; its maker is unknown.
label: Location
content: Currently not on view
topic: label: Subject
content: Mathematics
label: Subject
content: Timekeeping
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.319081
label: catalog number
content: 319081
label: accession number
content: 236085
objectType: label: Object Name
content: sundial, horizontal pedestal
physicalDescription: label: Measurements
content: overall: 22 cm x 27.3 cm x 27.3 cm; 8 21/32 in x 10 3/4 in x 10 3/4 in