Globe-type Electrostatic Machine

Description (Brief)
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.
This ½ scale-model of Benjamin Franklin’s electrostatic generator was made in 1897 in the Smithsonian’s model shop based on drawings of a machine at the Franklin Institute in Philadelphia. Their machine “was received by the Franklin Institute from Dr. J. Redmond Coxe in 1826 who said that the machine had belonged to Franklin himself.” Smithsonian curator George C. Maynard paid $25 for drawings of the Franklin Institute’s machine and then displayed this model at the 1897 Nashville Exposition.
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. This model differs somewhat from the Franklin-style machine collected over a half century later (catalog #EM*325513) but shows the basic design of a rotating glass globe, leather rubbing pad and brass charge collector. The Smithsonian preserves many authentic pieces of the past but occasionally uses reproductions and models when original objects no longer exist or would be impossible to display.
Location
Currently not on view
Object Name
scale model electrostatic machine
electrostatic generator
date made
1897-05-25
date loaned
1897-06-04
maker
Model Shop, United States National Museum
Physical Description
wood (overall material)
glass (overall material)
brass (overall material)
Measurements
overall: 84.5 cm x 30.8 cm x 39.4 cm; 33 1/4 in x 12 1/8 in x 15 1/2 in
ID Number
EM*181501
catalog number
181501
nonaccession number
1987.3093
subject
Science & Mathematics
Electrostatic Machines
See more items in
Work and Industry: Electricity
Electrostatic Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Additional Media

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