Photo by David Friend Productions, San Diego, California
6x7x12 ARITHMOMETER No. 1846 by THOMAS DE COLMAR
09-030. French, circa 1881, signed "THOMAS DE Colmar, INVENTEUR, EXPOSITION 16 RUE DE LA TOUR DES DAMES.., S'adresser, 44 RUE DE CHATEAUDIN, 44, PARIS" and serial numbered No. 1846. This small arithmometer has 6 entry setting sliders, 7 revolution counters, and 12 places in the results register. The 11 3/4" x 3 1/2" top plate is made of 1/8" thick brass plate and the 17 3/8" x 2 3/8" slide is made of 7/32" thick brass plate. It is mounted in a 18 1/4" x 7 1/2" x 4" plain oak case. The arithmometer is in very good display condition and is fully functional (the detent mechanism on one revolution counter is not working and must be reset by hand). There are less than 120 Thomas de Colmar arithmometers known in public collections world-wide and less than 65 in private collections. We have not seen one of the smaller models like this one offered for sale or at auction in many years.
This type of calculating machine was originally designed and introduced in 1820 by Chevalier Chas X Thomas de Colmar. Machines were made under his name until approximately 1887 (by Thomas de Colmar until his death in 1870, then by his son until his death in 1881, and finally by his grandson until 1887 when L. Payen took over). See pages 53-57 in Ernst Martin's "The Calculating Machines" for an extensive discussion the history and operation of the Thomas de Colmar Arithmometers.
