Cardew's patent voltmeter by Paterson & Cooper, London, England. Associated with Dr. J. Hopkinson FRS, 4 Westminster Chambers, Victoria Street, London, SW. In case. Cardew's patent voltmeter by Paterson & Cooper
Cardew patent voltmeter no. 651, in case, by W. T. Goolden & Co., London, England, 1880-1900. Cardew patent voltmeter no. 651 1880-1900
