Digibarn Collection ➔ Comptometer
Physical Object
2021.11.08.63.db
Comptometers by the Felt & Tarrant Manufacturing Company
The comptometer has an venerable place in the Digibarn physical collection: it is the very first artifact acquired for the collection, back in the late 1980s at a yard sale for $10. In fact it could be argued that this beautiful copper and brass box was partly the inspiration for the collection, together with the final public demo of the Xerox Star 8010. At the time I didn't know anything about it except that it was a thing of beauty. I cleaned it as best I could and wondered about the insides. There seemed to be a place for a crank which I didn't have, and the keys were stuck. Still I was fascinated by the dates on the stainless steel nameplate, which listed the first patent date as 1887! As it was in 1987 that I acquired it, I felt it was "the first personal computer" of the Victorian era.
All during through that period of my life in the 1980s and 1990s the "compt" followed me around, through multiple moves, and ended up at Ancient Oaks farm in the summer of 1998. It wandered into the Digibarn one night and became the first machine in the collection which was to explode in size over the next few years.
From Wikipedia's definition of comptometer:
A Comptometer is a type of mechanical (or electro-mechanical) adding machine. The comptometer was the first adding device to be driven solely by the action of pressing keys, which are arranged in an array of vertical and horizontal columns.The story of the Felt & Tarrant Comptometers as told by Comptometer Expert Brooke Boering
Comptometer is, strictly speaking, a trade name of the Felt and Tarrant Manufacturing Company of Chicago (later the Comptometer Corporation), but was widely used as a generic name for the class of device. The original design was patented in 1887 by Dorr Eugene Felt, a U.S. citizen.
Although primarily designed for adding, division, multiplication and subtraction could also be performed. Special comptometers with varying key arrays (with from 30 to well over 100 keys) were produced for a variety of purposes, including calculating currencies, time and Imperial measures of weight.
In the hands of a skilled operator, comptometers can add numbers very rapidly, since all the digits of a number could be entered simultaneously using as many fingers as is required, making them much faster than using an electronic calculator. Consequently, in specialist applications they remained in use in limited numbers into the 1990s, but with the exception of a handful of machines, have now all been superseded by the use of computer software.
Brooke Boering is one of the world's experts and greatest collectors of the comptometer. You can glean a bit of what he knows by by hearing and seeing him talk about them below.
Digibarn Radio audio piece: Brooke Boering on Felt & Tarrant and the comptometers
Digibarn TV video piece: Brooke Boering on Felt & Tarrant and the comptometers
Click on the links above to listen to or view Brooke Boering telling the story of the Felt & Tarrant company and its comptometers.
Our original "J" Model Comptometer
See Also:
Our Wolverine toy adding machine (a kind of baby comptometer)
Ray Mackay's Comptometer Memorized Notes including detailed descriptions of how they work