Mathematical Treasure: Thomas Hill’s Patent Model for a Key-Driven Adding Machine

Peggy A. Kidwell (National Museum of American History, Smithsonian Institution)

Thomas Hill's patent model for an adding machine.

Thomas Hill’s patent model for an adding machine, 1857, Smithsonian Institution negative number 87-5869.

In the nineteenth century, adding and calculating machines became practical commercial products. Several inventors proposed such machines, including Thomas Hill. Hill, a student of Benjamin Peirce during his undergraduate years at Harvard, became a Unitarian minister and a mathematics textbook author. He served as president of Harvard University from 1862 to 1868.

Hill took an active interest in invention and improvement. He called his machine an “arithmometer,” after the invention of the Frenchman Charles Xavier Thomas. Going beyond Thomas, he proposed that numbers should be entered by pressing keys. Although Hill’s patent did not lead directly to any commercial product, keys became a standard part of adding and calculating machines and survived into the age of the electronic calculator.

This object and other adding machines from the Smithsonian Institution’s National Museum of American History are shown at the website

Index of Mathematical Treasures

Index of Mathematical Objects