Description: Patent for a new and improved calculator. This design "consists in having a central disk provided on each side with a disk somewhat smaller, the three being pivoted centrally, so that the smaller disks on the sides may be rotated independently of the central disk. The central disk has twelve or more marginal figures on each side, equidistant from each other, and a column of figures extending inwardly from each marginal figure" (lines 19-27).
Date: November 24, 1885
Creator: Tucker, Argyle W.
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