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's patent voltmeter no. 2111, scaled 20-120V, made by W. T. Goolden & Co., London, England, 1880-1900, in box. Cardew's Patent Voltmeter no. 2111 1880-1900
Cardew patent voltmeter no. 651, in case, by W. T. Goolden & Co., London, England, 1880-1900. Cardew Patent Voltmeter no. 651 1880-1900