Dorr Felt's Comptometer
1887
Wooden Model
"Dorr E. Felt began working on what would become the Comptometer in 1885, making the first working version in metal in 1886 (the 1885 model was made mostly of wood and spare parts), and began low volume production by hand in 1887. Felt went into partnership with Robert Tarrant to produce and refine the Comptometer over many years. Although rather common due to their relatively high production, the Comptometer is an historically significant machine, being the first successful multiple order key driven calculator. Felt's new carrying mechanism was complex, but it met the high speed requirement of a key driven calculator. The 8 column Comptometer could add faster than an accountant's brain, which was its key to success."  

Richard Van Vleck - Scientific Medical & Mechanical Antique

"The wooden case model...

Serials below 15,000, altho there have been none discovered above 6121. This was, of course, the simplest model and was produced from 1887 thru 1903. The very earliest examples are on display at the Smithsonian Museum in Washington, D.C. and have no serial numbers. The lowest known "serialized" machine is 136 and, as of April 1999, was up for auction.

Several dozen of these wooden case machines seem to have survived with most in private hands.

The keystems were round with springs between the keytops and the keyplate. The keytops themselves were of the "typewriter" variety with a metal ring surrounding a celuloid inset containing the character.

The first known use was by the U. S. Treasury Dept in September, 1887 altho it is not known if this was the first true "sale" or placed on loan to gain commerical visability."

Brooke W. Boering (aka Vagabondo) - The Comptometer Memorial Website

Photo Source: The Comptometer Memorial Website

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