concept was brilliant. He used a set of revolving cylindrical
Napier Bones, for multiplication. Addition was performed
by turning the dials on the lower part of the machine.
These dials were connected with internal wheels, with
teeth on their circumference, causing a carry as the wheel
passed from 9 to 0. Subtraction was preformed by reversing
This model was built by IBM Germany, based on the few
available drawings, and is in our collection.
It was another 25 years before the first digital calculating