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Holtz-type influence machine

Holtz-type influence 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.
Many early electrostatic machines generated a charge by friction. In the later 19th century several designs were introduced based on induction. Electrostatic induction occurs when one charged body (such as a glass disc) causes another body (another disc) that is close but not touching to become charged. The first glass disc is said to influence the second disc so these generators came to be called influence machines.
James Wimshurst (1832-1903) designed a new type of influence machine in the early 1880s. Since they did not need to be pre-charged or primed in order to work, they represented a vast improvement on previous machines. This Wimshurst machine features two glass plates that rotate in opposite directions when the user turns the crank (the drive belts are missing from this unit.). Each plate has 24 wedge-shaped metallic contacts called sectors that generate the high-voltage charge and each plate is swept by a neutralizer arm that has two brass brushes. Two Leyden jars sit on opposite ends of the machine to one side of the plates and glass supports for the U-shaped combs are on the other side. The charge is collected by the combs and fed to the jars. A wire runs under the base and connects the two jars as needed. The machine was made in England by the firm Newton & Co., at 3 Fleet Street, London and imported to the U.S. by Arthur H. Thomas Co., Philadelphia.
Location
Currently not on view
Object Name
influence machine
electrostatic generator
date made
ca 1880
Measurements
overall: 25 3/4 in x 35 3/4 in x 17 1/2 in; 65.405 cm x 90.805 cm x 44.45 cm
ID Number
EM.327656
catalog number
327656
accession number
268279
Credit Line
from Rutgers University, thru Peter Lindenfeld
See more items in
Work and Industry: Electricity
Science & Mathematics
Data Source
National Museum of American History
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