Cylinder-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 table-top electrostatic cylinder machine came to the Smithsonian along with a large assortment of equipment used by traveling lecturer and scientific showman Charles Came (1806-1881) and his successors. From the 1840s through the 1870s, Came traveled around New York State entertaining audiences with magic lantern shows and demonstrations of electrical phenomenon. His son-in-law Samuel Corby (1839-1913) continued the traveling shows for about 30 years after Came’s death, and John S. Fisher (1907-2002) revived the shows in the 1950s. Some of Came’s equipment was homemade and other pieces were purchased from commercial suppliers.
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. No maker’s markings appear on this machine so we do not know its origin.
Location
Currently not on view
Object Name
electrostatic generator
frictional cylinder electrostatic machine
Physical Description
wood (overall material)
glass (overall material)
brass (overall material)
plastic (overall material)
metal (overall material)
silk (overall material)
rubber (overall material)
metal foil (overall material)
Measurements
main section: 21 in x 37 in x 25 in; 53.34 cm x 93.98 cm x 63.5 cm
prime conductor: 16 in x 8 3/4 in x 4 in; 40.64 cm x 22.225 cm x 10.16 cm
conductor stand: 15 3/4 in x 3 1/2 in x 3 1/2 in; 40.005 cm x 8.89 cm x 8.89 cm
friction stand: 16 1/2 in x 7 in x 5 1/2 in; 41.91 cm x 17.78 cm x 13.97 cm
curved shim: 4 3/8 in x 1 3/8 in x 3/16 in; 11.1125 cm x 3.4925 cm x .47625 cm
rectangular shim: 3 3/8 in x 1 1/4 in x 3/16 in; 8.5725 cm x 3.175 cm x .47625 cm
ID Number
1989.0743.302
catalog number
1989.0743.302
accession number
1989.0743
collector/donor number
1
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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