Halden "Calculex" patent circular slide rule
Halden "Calculex" patent circular slide rule (5 inches diameter), c. 1906.
- Object Number:
- 1970-639/1
- type:
- circular slide rule
- Image ©
- The Board of Trustees of the Science Museum
Halden "Calculex" patent circular slide rule (5 inches diameter) in case, c. 1906
Halden "Calculex" patent circular slide rule (5 inches diameter), c. 1906.
Case for Halden "Calculex" patent circular slide rule.