Cylinder-type Electrostatic Machine

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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.
For many years electrostatic machines like this one from Princeton were considered essential tools for teaching the basic concepts of electrical science and saw significant use. This table model is unmarked and of fairly crude workmanship. The wood frame holds a glass cylinder turned by a direct-drive crank although the handle is missing. Wooden hubs hold the cylinder in the frame. No rubbing pad or charge collector remain on 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.
Location
Currently not on view
Physical Description
wood (overall material)
glass (overall material)
metal (overall material)
Measurements
overall: 25 in x 13 1/2 in x 20 in; 63.5 cm x 34.29 cm x 50.8 cm
ID Number
EM.325512
catalog number
325512
accession number
2008.0088
Credit Line
from Princeton University, Department of Physics
See more items in
Work and Industry: Electricity
Science & Mathematics
Electrostatic Machines
Data Source
National Museum of American History, Kenneth E. Behring Center

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