Halden Calculex Patent Circular Slide Rule
£140
Dimensions
6 cms diam
Circa
1910
Maker
Halden
Country of manufacture
UK and Ireland
Description
A Halden Calculex of standard form with original case and book of instructions
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Dealer information
Fletcher
Fletcher Wallis
Fletcher Wallis sells objects and books relating to the history of science, medicine and technology from his unit at Admiral Vernon Arcade Portobello Road. He publishes books through Vernier Press, including Antique Medicine Chests, and Corkscrew Patents from 1795. He has been dealing for thirty five years.
