Automatic Arithmotor. This Patent Office model for an adding machine has eight counting wheels that rotate on a common crosswise shaft. Around the edge of each wheel, the digits from 0 to 9 are printed repeatedly. Attached to each cylinder is a toothed revolving disc.

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Size: 1936px × 1291px
Photo credit: © SBS Eclectic Images / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: mathematics, medicine, science