Signedon top: CARHART-CLARK / STANDARD CELLS / WILL YOUNG & CO. PHILA.
FunctionStandard cells produce a known and stable voltage for the calibration of electrical measurement instruments.
ProvenanceFrom the Department of Physics, Harvard University.
Related WorksJohn Henderson, Practical Electricity and Magnetism (London, 1908), vol. II, p.198, fig. 90.