Henley-type electrometer
Date: 1820-1870
Inventory Number: DW0509
Classification: Electrometer
Subject:
Maker: French ?
Cultural Region:
Dimensions:
34.3 × 10 × 8 cm (13 1/2 × 3 15/16 × 3 1/8 in.)
Description:
This electrometer consists of a semicircular dial made of bone, attached vertically to a mahogany stem ending in a mahogany ball on top. The pillar is held by a brass sleeve on a round metal base.
The semicircular dial has a scale in degrees marked from 0 vertically down, up to 100 degrees in 10 degree intervals, and lines etched on the dial extend from the center towards the edges at these intervals. The lines continue on the upper half of the semicircle where the numbers are missing. Hinged at the center of the dial is a thin, whale bone pointer, which would originally have a pith ball at its end, now missing.
The semicircular dial has a scale in degrees marked from 0 vertically down, up to 100 degrees in 10 degree intervals, and lines etched on the dial extend from the center towards the edges at these intervals. The lines continue on the upper half of the semicircle where the numbers are missing. Hinged at the center of the dial is a thin, whale bone pointer, which would originally have a pith ball at its end, now missing.
Signedunsigned
FunctionElectrometers are devices to measure the amount of electric charge on an object. In Henley electrometers, one would touch the metal base with the charged object, following which the charge on the base and sleeve would repel the pith ball (missing here), making an angle on the dial, which would be proportional to the charge on the object.
Other examples are found on the following website.
Other examples are found on the following website.