Addometer
Addometer #3119 x 23.5 cm , Ambrotype , 2015 Addometer #3219 x 19 cm , Tintype , 2015 Addometer #3519 x 23.5 cm , Ambrotype , 2015
Addometer was manufactured by the Reliable Typewriter and Adding Machine Co. in Chicago from early 1900’s until late 1960’s. The standard Addometer which measures 29 x 5 x 1.5 cm. can be used to add and subtract numbers up to 8 digits. In addition to the standard model there were also special versions like Feet & Inches Addometer and Sterling Currency Addometer. It was probably the first handheld calculating device operated using a stylus.

Addometer 1900’lerin başından 1960’ların başına kadar Chicago’daki Reliable Typewriter and Adding Machine Co. tarafından üretilmiştir. Cetvele benzeyen 29 x 5 x 1.5 cm. boyutlarındaki standart modeli sekiz haneye kadar toplama ve çıkartma yapabilir. Ayrıca Feet & Inches Addometer ve Sterling Currency Addometer adında özel modelleri de vardı. En önemli özelliği, muhtemelen kalem (stylus) ile çalışan ilk hesap makinesi olmasıdır.

Reference : Vintage Calculators Web Museum
Calculus : Addometer Adix Burroughs Curta Fowler Odhner Soroban
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