Webb Adder


This two-wheeled stylus-operated non-printing adding machine is in a wooden frame. The large brass wheel has a ring of holes and the numbers 00 to 99 stamped around the edge. The numbers 0 to 99 also are stamped around the window for the larger wheel. Numbers are added by rotation of the wheels. Answers are recorded on a pedometer-like dial that has separate windows for ones, tens, hundreds, and thousands. The frame is screwed to the cover plate. There is a stylus. The large wheel is marked: C.H.WEBB. N.Y. It is also marked: “THE ADDER" PATD MARCH 10TH 1868. The back has the serial number: C1053. The dial is a modification of the instrument. It is marked on paper attached over the small wheel: N.Y.STANDARD WATCH COMPANY.

Charles Henry Webb (1834-1905) was a journalist, playwright, poet, and roamer. He patented a second version of this device in 1889. This example was owned by the Draper family of New York.


C. H. Webb, “Improvement in Adding Machines,” U.S. Patent 75322, March 10, 1868.

“Machine for Addition,” Journal of the Franklin Institute, 60 (1870): pp. 8-9.

P. A. Kidwell, “The Webb Adder,” Rittenhouse, 1 (1986), pp. 12-18.

E. Martin, The Calculating Machines (Die Rechenmaschinen), trans. P. A. Kidwell and M. R. Williams, Cambridge: MIT Press, 1992, p. 63.

Date Made: 1868-1889

Patentee: Webb, Charles H.Maker: Webb, Charles H.

Location: Currently not on view

Place Made: United States: New York, New York CityPlace Patented: United States: New York, New York City

Subject: Mathematics


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


Exhibition Location:

Credit Line: Gift of John William Christopher Draper and James Christopher Draper

Data Source: National Museum of American History

Id Number: MA.335359Accession Number: 304826Catalog Number: 335359

Object Name: adding machine

Physical Description: glass (overall material)brass (overall material)brass, nickel-plated (overall material)paper (overall material)wood (overall material)Measurements: overall: 2.5 cm x 17.3 cm x 12.2 cm; 31/32 in x 6 13/16 in x 4 13/16 in

Guid: http://n2t.net/ark:/65665/ng49ca746a4-f603-704b-e053-15f76fa0b4fa

Record Id: nmah_690287

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