Davis and Kidder's magneto-electrotherapy machine, hand-cranked, made by W H Burnap of Lowell, Mass., U.S.A., 1854-1898 Magneto-electrotherapy machine 1854-1880
Davis later C19 magneto-electric therapy machine with mechanism to show magnet keepers position on exterior dial, probably English-made, 1860-1890 Davis later C19 magneto-electric therapy machine 1860-1890
Magneto electrotherapy machine, Davis type, possibly made by Elliott of London, 1860-1920 Magneto electrotherapy machine 1860-1920