Warren Experimental Calculating Machine Model


This is the second version of Warren’s calculating machine. Across the front is a brass rod with ten large teeth, one shorter one, and a hollow brass cylinder. Between the teeth are ten levers that link to toothed segments at the back of the machine. The front and back are open; the sides are of a ferrous metal painted black. At the top is a hollow brass rod, mounted across the machine, which has two brass circular structures on it. This is used as a plunger to activate the mechanism. Brass rods with large teeth extend from both sides of the back. There also is a ferrous piece in the shape of a large comb that is attached to the top back of the piece. The machine appears incomplete.

There are no maker’s marks.

Compare MA.311938 and MA.311939.

According to L. Leland Locke, Warren was a teacher, itinerant photographer and then watchmaker by trade. His invention was inspired by his reading about Charles Babbage’s difference engine in 1864. He designed his machines to demonstrate what might be done with machinery, not for sale. A more complete form of the machine, which was exhibited after Warren’s death, is now in the collections of the Michigan State University Museum.


L. Leland Locke, “The Warren Calculating Engine,” Business Equipment Topics, October, 1931, vol. 79, pp. 8, 9. 48, 49.

"Home and Foreign Gossip," Harper’s Weekly, May 22, 1875, vol. 19 #960, p. 423.

Date Made: 1874

Location: Currently not on view

Place Made: United States: Michigan, Three Oaks

Subject: Mathematics


See more items in: Medicine and Science: Mathematics, Calculating Machines, Science & Mathematics


Exhibition Location:

Credit Line: Gift of L. Leland Locke

Data Source: National Museum of American History

Id Number: MA.311939Catalog Number: 311939Accession Number: 155183

Object Name: calculating machine

Physical Description: ferrous metal (overall material)brass (overall material)Measurements: overall: 18.2 cm x 66.3 cm x 30.2 cm; 7 5/32 in x 26 3/32 in x 11 7/8 in

Guid: http://n2t.net/ark:/65665/ng49ca746a5-3bcf-704b-e053-15f76fa0b4fa

Record Id: nmah_694180

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.