Images(4)

Henley-type electrometer

Date1820-1870

Inventory NumberDW0509

ClassificationElectrometer

Subject

Maker French ?

Cultural Region

Dimensions34.3 × 10 × 8 cm (13 1/2 × 3 15/16 × 3 1/8 in.)

Material

DescriptionThis 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.

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.

ProvenanceDavid Wheatland purchased from Saul Moskowitz (Historical Technology, Inc.), Marblehead, Massachusetts, December 2, 1976 (catalog 113, #199).