Hand-held plate frictional electrostatic generator

Hand-held plate frictional electrostatic generator

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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.
In the latter 1700s electrical researchers adopted improved electrostatic machines that replaced earlier glass cylinders with a flat glass plate. This increased the machines’ efficiency by passing the glass plate between leather rubbing pads that increased the contact area. Experience with plate machines brought many design variations with sizes ranging from small table-top units for laboratory use to large cabinets that powered early x-ray machines.
This small, hand-held electrostatic generator is unmarked so who made the unit is unknown. Presumably used for laboratory experiments it features a hard rubber disc that rubs against a single felt rubbing pad. The disc is mounted in a slit made in a cylindrical rod. Brass spheres are attached to each end of the rod. The crank handle on one side turns the glass plate.
Location
Currently not on view
Object Name
electrostatic generator
Electrostatic Machine
Measurements
overall: 33.7 cm x 12 cm x 9 cm; 13 9/32 in x 4 23/32 in x 3 17/32 in
ID Number
EM.318434
catalog number
318434
accession number
234642
Credit Line
from Hamilton College
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Work and Industry: Electricity
Data Source
National Museum of American History
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