This instrument is a battery of six capacitors (or condensers) enclosed in a wooden frame, and named after the American scientist and statesman Benjamin Franklin (1706 – 1790). Each cell consists of a capacitor formed by a framed glass plate with sheets of metal foil (the conductors) glued with shellac to both sides.

The conductors of adjacent capacitors can be put in contact by means of a rod with a brass plate at each end, fixed in a wooden bridge. The contacts at the ends of the device serve for connection to an electrostatic machine.
The capacitors thus arranged are connected in series, with an equal charge on each condenser and a potential difference shared between them.

The instrument was acquired between 1821 and 1827.

Device on display.