Dated 1843. From Scientific apparatus, musical instruments and telegraph equipment, [1834-1875].

Single cylinder rheostat devised by Wheatstone to maintain a constant current by adjusting or varying the resistance of a circuit where the resistance is low.  Consists of a cylinder wound with wire, brass fixtures on a wooden base. [See Wheatstone’s Bakerian Lecture for 1843 An account of several new Instruments and Processes for determining the Constants of a Voltaic Circuit published in the Philosophical Transactions of the Royal Society.]