Images(5)

Coad's electric battery

Date1850-1860

Inventory NumberDW0405

ClassificationBattery

Subject

Maker Patrick Coad 1783 - 1872

Cultural Region

Dimensions41 x 27.5 x 20.5 cm (16 1/8 x 10 13/16 x 8 1/16 in.)

Material

DescriptionAn electric battery made of alternating copper and zinc plates that would have originally been immersed in an acidic solution held in a now lost glass jar. The plates are held by a wooden plank attached to brass screws that allow it to be raised by the turning of a handle on top of a stylized wooden frame. The raising mechanism consists of three cogwheels: a central one with the handle, and two smaller ones on each side that are attached to the screws that hold the wooden plank with the metallic plates.

The wooden frame has a metallic plate with a scale on one side, and another on its top rim facing forward and engraved "Coad's Patent Graduated Battery".

Signedengraved on metallic plate: Coad's Patent Graduated Battery

FunctionAs most batteries, this one provides a voltage difference by the chemical reaction of two different metals with an acidic solution. This battery in particular can provide varying amounts of current to a circuit depending on how much the plates are immersed in the solution. This is controlled with the handle atop the wooden frame, and the scale on one side provides a measure of how deep the plates have been immersed.

Its original glass jar has been lost, and the plates are very corroded from use. As a result of partial immersion, they are much more corroded near their bottom. It was apparently used for medical purposes, based on the theory of galvanism. For more on the battery, see the following website.

ProvenanceDavid Wheatland purchased from Avis & Rockwell Gardiner, Stamford, Connecticut, at the Ellis Memorial Antiques Show, October 30, 1969.