Author's Self-Operating Cataphoric Rheostat. Fig. 166, page 415, 'Dental Electricity' by Levitt E Custer, 1901.
Licence: Attribution 4.0 International (CC BY 4.0)
Credit: Author's Self-Operating Cataphoric Rheostat. Fig. 166, page 415, 'Dental Electricity' by Levitt E Custer, 1901. Wellcome Collection. Source: Wellcome Collection.
