Patent Model for an Adder with Carry by Alonzo Johnson

Description:

This patent model for an adder has as its base two concentric brass discs, one rotating inside the other. The rim of the outer disc has the numbers from 0 to 99 engraved around its edge. The inner disc has one hundred small holes marked evenly around its edge. These also are numbered 0 to 99. Two steel arms pivot at the center of the disc. The longer arm has a pin on the underside that fits into the holes and a small knob on the upper side so that it can be rotated. A protruding pin set at 0 in the outer circle stops the motion of this arm. It is used to add numbers up to 99.

When the total on the inner disc exceeds 99, the the smaller arm advances one digit, indicating hundreds. The number of hundreds entered appears in a window in a small disc that is on top of three relatively small gears concentric to the large discs. Hundreds apparently cannot be entered directly. The adder has a handle that projects from the center of the back.

Census records list two men who may have been Alonzo Johnson, the inventor of this device. Both were machinists. One Alonzo Johnson (no middle initial) was born 12 February 1828 in Bangor, Maine, the son of Louisa Underwood and Dolliver Johnson. Alonzo's father was a railroad engineer, then a superintendent of locomotive power on the Fitchburg Railroad and then associated with the Illinois Central. This Alonzo Johnson married in about 1850, and lived in Springfield with his wife Sarah and their children from at least 1870 through 1900. Census records also list an Alonzo H. Johnson, born about 1828 in Connecticut, who was living with his wife Hannah in Springfield in 1870, 1880 and 1900.

Alonzo Johnson of Springfield took out eight patents, the first two for calculating devices. These were #73732 (granted January 28, 1868, with James A. Loomis as co-inventor and Charles Gifford of Gardiner, Maine, as assignee), and #85229 (taken out December 22,1868, and assigned to Sylvester Bissell and Andrew West of Hartford). Later patents were for nut-locks (#188055, granted March 6, 1871), slitting lock nuts (#231492, granted August 24, 1880), a car-brake (#235152, granted December 7, 1880), a card-cutter (#241372, granted May 10, 1881), a sash-fastener (#255144, granted April 11, 1882), and a gumming device for envelope machines (#397798, granted February 12, 1889).

Compare to 1990.0318.01.

Reference: Alonzo Johnson, “Improvement in Calculating-Apparatus,” U.S. Patent 85,229, December 22, 1868.

P. Kidwell, "Adders Made and Used in the United States," Rittenhouse, 1994, 8:78-96.

Date Made: 1868

Patentee: Johnson, AlonzoMaker: Johnson, Alonzo

Location: Currently not on view

Place Made: United States: Massachusetts, SpringfieldPlace Patented: United States: Massachusetts, Springfield

Subject: Mathematics

Subject:

See more items in: Medicine and Science: Mathematics, Adder, Science & Mathematics

Exhibition:

Exhibition Location:

Data Source: National Museum of American History

Id Number: MA.252695Accession Number: 49064Catalog Number: 252695

Object Name: adder with carryObject Type: Patent Model

Physical Description: brass (overall material)wood (overall material)steel (overall material)Measurements: overall: 16.5 cm x 18.5 cm x 18.5 cm; 6 1/2 in x 7 9/32 in x 7 9/32 in

Guid: http://n2t.net/ark:/65665/ng49ca746a5-1a58-704b-e053-15f76fa0b4fa

Record Id: nmah_690837

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.