The "Sphere" Electric Cable Engine. Fig. 89, page 221, 'Dental Electricity' by Levitt E Custer, 1901.
Licence: Attribution 4.0 International (CC BY 4.0)
Credit: The "Sphere" Electric Cable Engine. Fig. 89, page 221, 'Dental Electricity' by Levitt E Custer, 1901. Wellcome Collection. Source: Wellcome Collection.
