Globe-type Electrostatic Machine
date: label: date made
content: ca 1750
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 portable generating machine from around 1760 comes with an experimental kit of accessories. Early electrostatic machines generated a charge by spinning a globe against a pad. The charge could then be used directly in experiments or transferred from the globe to a Leyden jar. The hand-cranked ball of sulfur on this machine rubbed against a leather pad. The pins on the brass rod set close to the ball transferred the charge from the ball to the rod, called a prime conductor. Suspended from a frame by insulating silk threads, the charged prime conductor allowed a researcher to show electrical properties like attraction, repulsion, and strength of charge. Accessories include pith balls, a chime of bells, a Leyden jar, and assorted plates, hooks and dischargers.
label: Description (Brief)
content: This machine is especially interesting as we have an original design drawing in the collection showing this type of machine--catalog #1988.0621.01.
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
label: Exhibition
content: The Electric Dr. Franklin
label: Exhibition Location
content: National Museum of American History
creditLine: label: Credit Line
content: Acquired in part by the generosity of Edison Electric Institute
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1983.0190.01
label: accession number
content: 1983.0190
label: catalog number
content: 1983.0190.01
objectType: label: Object Name
content: generator, electrostatic
label: Object Name
content: frictional globe machine
label: Object Name
content: electrostatic generator
label: Other Terms
content: frictional globe machine; Electrostatic 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: silk (overall material)
label: Physical Description
content: metal (overall material)
label: Physical Description
content: sulfur (overall material)
label: Physical Description
content: leather (overall material)
label: Measurements
content: overall: 57 cm x 27.5 cm x 67 cm; 22 7/16 in x 10 13/16 in x 26 3/8 in