Stephenson Adding Machine

Archibald M. Stephenson of Manteno, Illinois, received his patent No 137167 for adding machine on March 25, 1873 (see the lower drawing).

The patent drawing Stephenson's adding machine

The original Stephenson's Adding Machine is a four-wheeled adding machine with automatic carry. There are also two-wheeled versions sold under a number of different names (Perfection Adding Machine, Universal Adding Machine, etc.), made by different manufacturers, which are sold in the end of 19th and the beginning of 20th century for $1-$2. The two-wheeled production version is somewhat different (see the lower photo), since the user may enter only single digits in the right wheel. There is an automatic carry to the left wheel, which registers up to 19, so that the maximum sum is 199. The Stephenson seems to have been an aid for people adding long columns of figures using paper and pencil.

Stephenson's Adding Machine