Improvements in bi-focal lenses and their manufacture, and in apparatus to be employed in the said manufacture / [Malcolm Bentzon].
- Bentzon, Malcolm.
- Date:
- 1906
Licence: Public Domain Mark
Credit: Improvements in bi-focal lenses and their manufacture, and in apparatus to be employed in the said manufacture / [Malcolm Bentzon]. Source: Wellcome Collection.
5/16 (page 5)