A Rare Proell Pocket Calculator or New Slide Rule
English, c 1901-2, complete with card and celluloid scales, instruction manual and cloth case, 15.8m x 10.8cm. Note: the UK slide Rule Circle states that very few examples are known to exist.
Sold for £192
Result plus buyers premium
English, c 1901-2, complete with card and celluloid scales, instruction manual and cloth case, 15.8m x 10.8cm. Note: the UK slide Rule Circle states that very few examples are known to exist.