Nicholson revolving doubler

Nicholson revolving doubler

<< >>
Usage conditions apply
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.
This small revolving doubler, developed by William Nicholson (1753-1815) in England, shows the basic principle of an influence machine. The user turns a crank that rotates a charged disc in front of the stationary discs. The rotating disc induces a charge on each stationary disc as it passes. The two stationary discs on this piece are connected briefly so both become charged. The charge is almost doubled each time the rotating disc passes a stationary disc and the effect repeats, building up a high voltage on the brass ball. This doubler was made in London by instrument makers William and Samuel Jones in the early 1800s. Since the charge is not quite doubled the term multiplier was later used for these types of devices.
Currently not on view
Object Name
Revolving Doubler
influence machine
electrostatic generator
date made
ca 1810
W. & S. Jones
overall: 11 1/2 in x 7 1/4 in x 8 in; 29.21 cm x 18.415 cm x 20.32 cm
ID Number
catalog number
accession number
collector/donor number
Credit Line
from Columbia University, Department of Physics, thru Alvin P. Tramm
See more items in
Work and Industry: Electricity
Science & Mathematics
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object