Faraday and electrical conductors. An examination of the copper wire used by Michael Faraday between 1821 and 1831

Samples of copper wire from the coils and toroids made and used by Michael Faraday (1791¿¿1867), during the period of his greatest electrical discoveries, were inspected for quality of manufacture and tested chemically and electrically to determine metal purity and electrical conductivity. The outcome of the enquiry establishes that the copper wire of Faraday´s time was not only indifferently made but retained a wide range of impurities. As a consequence, an extreme range of conductivities was found corresponding to the type, and concentration, of elemental impurities in any one sample. The paper concludes that there is some basis for believing that had other factors weighed slightly more against Faraday, then his failure to be selective in the conductivity of his wire may well have lost him the credit for the discovery of electromagnetic induction.