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  • Images (4)

electrophorus

  • Images (4)

electrophorus

Date: circa 1800
Inventory Number: DW0305
Classification: Electrophorus
Subject:
electrostatics,
Maker: French ?
Maker: English ?
Cultural Region:
France, England,
Dimensions:
13.5 × 13 × 13 cm (5 5/16 × 5 1/8 × 5 1/8 in.)
Material:
rubber, brass,
Description:
This object has several components. The base is a thin metal disc with a lipped rim. Near its middle, the base rises to create a stout cylinder. Out of this cylindrical portion of the base emerges a tall slightly thicker rod, made of dark rubber. At the top it is barely rounded.
Signedunsigned
FunctionThis component would have been stacked atop two other discs (one made of rubber and one of metal - see for example, 0503b and 0503c) in order to generate electricity by means of electrostatic induction.

To create electricity, the user would "evenly" rub this component with a cloth, often made of cat's skin. The negative charge produced by the friction of the second disc, induces a positive charge on the part of this component in contact with it (the bottom of this component) and a negative charge on the part furthest from it (the top of it).

In this condition, if this component is raised from the second disc by means of its rubber insulating handle, no electrical effects will be noticed since the two opposite and equal charges unite and neutralize each other. If, however, this component is first touched by the user's finger and then raised from the second disc it will be found positively charged.

This charge can then be transferred to a Leyden jar, etc. This instrument was popular at least in part because it was a reliable and easy-to-use source of charge and voltage for experimental researches in electrostatics.
Curatorial Remarks
No rubber piece for this to rest on. missing?
Related WorksFor more specific information about the electrophorus, see the Encyclopedia Britannica entry here or this entry website affiliated with Florida State University.

One may also look at the entry for Volta's Electrophorus in: George Adams, An essay on electricity: explaining the theory and practice of that useful science; and the mode of applying it to medical purposes (London: R. Hindmarsh, 1787), 205.

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