Register All Cord Electric Engine. Fig 90, page 222,'Dental Electricity' by Levitt E Custer, 1901.

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: Register All Cord Electric Engine. Fig 90, page 222,'Dental Electricity' by Levitt E Custer, 1901. Wellcome Collection. Source: Wellcome Collection.