Portable Gaiffe induction coil in mahogany box with mercury sulphate battery and assorted electrodes 1870-1880
Portable Gaiffe induction coil in mahogany box with mercury sulphate battery and selection of electrodes 1870-1880
Cylindrical induction coil of vulcanite with multi-core mounted on wooden base with trembler 1890-1900
Induction coil (de Watteville's coil) mounted on wooden base with twin solenoid trembler and power switch 1890-1900