Archive of Collections

Details and Image

TypeModel No.MakerCountryConstruction
DateScale LengthArea of Use
Pocket Watch Slide Rules
Waddington / Lord's Calculator Type 1
Richard Waddington
Ø 6.8 cm
Basic Calculations

Notes: Design based on 2nd 1903 patent and is the 1st of four versions from three other makers or retailers. Unlike other pocket-watch types this calculator has no index pointer or hairline on the glass.

Image 1

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Image 5