Mathematical Chart, Roche Spiral Adder


This octagonal wooden stick has a spiral drawn around it which is divided lengthwise to form two adjacent spirals. Numbers in each spiral begin at zero and increase clockwise going down the stick. The number in any one space is always four greater than the number in the space below it. The rule may be used to find the sum of a number on the stick and any digit from one to nine. Roche prepared models of the stick in both wood and paper. There is no indication in the patent that a model was submitted with it, and no patent tag on the object.

A mark on the wooden rule reads: SPIRAL ADDER (/) INVENTED BY ROBERT FREDERICK ROCHE (/) FORT FOOTE MARYLAND. The paper version has a similar mark. It also has the mark: 27-99. This is a catalog number of the Museums of the Peaceful Arts. It also has a paper tag that reads: 17.

For a rule associated with Roche, biographical information about him, and additional references, see 1984.1080.02.


Robert F. Roche, “Improvement in Adding-Sticks,” U.S. Patent 206136, July 13, 1878.

Date Made: 1878

Location: Currently not on view

Place Patented: United States: Maryland, Fort Foote Village

Subject: Mathematics


See more items in: Medicine and Science: Mathematics, Mathematical Charts and Tables, Science & Mathematics


Exhibition Location:

Credit Line: Gift of L. Leland Locke

Data Source: National Museum of American History

Id Number: MA.311957Accession Number: 155183Catalog Number: 311957

Object Name: digital devicemathematical chart

Physical Description: wood (overall material)paper (overall material)Measurements: overall: 2 cm x 30 cm x 2 cm; 13/16 in x 11 13/16 in x 13/16 in


Record Id: nmah_690859

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