AddersNotched Band Adders
Building on ideas of Perrault and de Caze, in an instrument patented in Russia in 1847 Kummer replaced the wooden rods on an adder with metal bands notched on each side. Kummer’s idea was adopted by the Frenchman Troncet, who published what he called an Arithmographe in the 1890s. Adders with notched bands became the most common form of the instrument sold in the United States in the 20th century.
These stylus-operated instruments generally had a crook at the top of each column, to allow one to move adjacent bands in carrying (or, in some cases, borrowing) a digit. They were manufactured around the world. Occasionally, notched band adders were combined with a slide rule, to ease multiplication and division. A special form of the instrument, designed for computer programmers, aided calculations in base 60 rather than usual decimal arithmetic.
"Adders - Notched Band Adders" showing 1 items.
- This black and silver-colored metal instrument is a notched band adder with nine bands, eight columns, and a nine-digit display. Its bracket-shaped columns are color-coded for dollars and cents. A plate attached to the top which covers the lower part, for use in addition, or pivots and covers the upper part, for use in subtraction. Across the top is a zeroing bar. The device includes a metal stylus and fits in a black plastic case which also holds several yellowing sheets of paper. Instructions are stored with the object.
- This British adder was received at the Smithsonian in about 1970. It seems likely that it was made in the mid-20th century.
- Currently not on view
- date made
- ca 1950
- ID Number
- accession number
- catalog number
- Data Source
- National Museum of American History, Kenneth E. Behring Center