Adding Machines
Stylus-Operated Adding Machines

An image displaying several adding machines from the Division of Medicine and Science.

In 1642, while he was still a teenager, the Frenchman Blaise Pascal invented one of the first machines that could add automatically. Numbers were entered by rotating wheels with a pointed rod or stylus. Carrying took place through the fall of a weight. Some fifty copies of Pascal’s machine were made in his lifetime, mainly for the cabinets of curiosity of well-to-do nobles. In the eighteenth century, similar machines were made, such as one build by Jean Lepine, clockmaker and mechanician to French King Louis XV. In Lepine’s elegant brass machine, carrying took place through the flex of a spring, not the fall of a weight.

In the second half of the 19th century, a variety of much humbler stylus-operated adding machines were patented in the United States. At least three of them went on the market. Two, based on inventions of John Groesbeck and of A. M. Stephenson, had modest sales. The third, invented by journalist Charles H. Webb and sold as the Webb adder, was a sufficient commercial success to boast distinct models, patented in 1868 and 1889.

A.M. Stephenson described a small adding machine with several dials, but only sold one that handled two digits. In the 1840s the Frenchman Didier Roth had designed an improved stylus-operated adding machine that was small and light weight, but had several dials. Roth did not sell his machines successfully, but in the early 20th century such instruments became quite common. One of the first to sell widely in the U.S. was the Calcumeter, patented by James J. Walsh of New Jersey in 1901. Similar instruments, made from metal or later plastic, would sell into the 1970s.

Other small adding machines had parallel rods or chains that moved either crosswise or from top to bottom. Some of these looked quite a bit like contemporary adders, although they had a mechanical carry.