Lightning Adding Machine Sales Company Addometer
1950s
Frank Baldwin based his calculating machine on the invention of Gottfried
Leibniz, the German mathematician and philosopher who used a collection
of pinwheels and stepped cylinders containing ridge-like teeth of different
lengths corresponding to the digits 1 through 9. Baldwin replaced Leibniz's
cylinders with a single cylinder with a variable number of teeth (1 through
9) protruding according to the motion of the setting lever. This evolved
into the machines you see here which use a stylus to turn the wheels like
a telephone dial.
Donor: Jim & Marie Petroff
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