Cylinder-type Electrostatic Machine
date: label: date made
content: ca 1785
notes: label: Description (Brief)
content: People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
label: Description (Brief)
content: This machine, made around 1785, has a hand-cranked cylinder and a leather pad with silk cloth to mounted on one side. The mount is adjustable by means of the wooden screw set in the base. A prime conductor would be mounted opposite the rubbing pad but is missing from this unit. During the 1750s electrical researchers refined the design of electrostatic machines by replacing earlier spherical globes with a glass cylinder, a design used for many years. This change increased the surface area of the glass in contact with the rubbing pad and improved the efficiency of the generator. There is no extant maker's mark on the machine although it is of the type designed by Edward Nairne in the 1780s. Nairne (1726-1806) of England made electrical and other scientific devices.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
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content: Science & Mathematics
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content: Electrostatic Machines
creditLine: label: Credit Line
content: from Wabash College, Physics Department
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.322996
label: catalog number
content: 322996
label: accession number
content: 249201
objectType: label: Object Name
content: galvanometer
label: Object Name
content: electrostatic generator
label: Object Name
content: electrostatic machine
label: Other Terms
content: galvanometer; Measuring Devices
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: glass (overall material)
label: Physical Description
content: brass (overall material)
label: Physical Description
content: leather (overall material)
label: Physical Description
content: cloth (overall material)
label: Measurements
content: overall: 25 1/2 in x 25 3/4 in x 16 1/4 in; 64.77 cm x 65.405 cm x 41.275 cm