Dated 1840-1845. From Scientific apparatus, musical instruments and telegraph equipment, [1834-1875].

Prototype or demonstration model of the 'Wheatstone Bridge' or 'Differential Resistance Measurer' originally devised by Samuel Hunter Christie and further developed and promoted by Wheatstone. An electrical circuit designed to measure unknown resistance by using components with known resistance.  Consists of a series of wires and connectors attached to a wooden base in a diamond shape. [See K/PP107/1/4/44 for a diagram.]