Webb Ribbon Adder

This silver-colored metal instrument has eight columns, each revealing a perforated paper strip. On the right side of the strip, the perforations are numbered with the digits 0, 1, 2, 3, . . . 9. These numbers appear in windows at the bottom of the columns when terms are entered. On the left side of the strip there are 20 perforations with no number (ten of these are never seen). Beyond this, ten perforations are numbered on the left with a “1," ten with a “2,” and so forth to ten numbered “29.” These numbers to the left indicate terms to be carried. They appears in windows across the top of the adder. A zeroing handle is on the right. The instrument has a fold-up support and fits in a leather-covered, velvet-lined case. Two pencil stubs, one with a stylus, are also in the case.
The Russian J. Diakoff had suggested in 1829 that one might represent numbers on an adder by a long strip with regularly spaced holes. The New York journalist and inventor Charles Henry Webb picked up on this idea. He applied for a patent in the United States in 1886, received one in England in 1888, and patented the Webb ribbon adder in the United States in 1891. He sold this example to New York meteorologist Daniel Draper, but the device never proved popular. Webb also patented a small adding machine, marketed as the Webb adder, that was a more successful product.
References: P. Kidwell, “Scientists and Calculating Machines,” Annals of the History of Computing 12 (1990): 31-40.
P. Kidwell, "Adders Made and Used in the United States," Rittenhouse, 1994, 8:78-96.
C. H. Webb, “Adding Machine,” U.S. Patent 465120, December 15, 1891.
Currently not on view
date made
Webb, Charles H.
place made
United States: New York, New York
Physical Description
leather (overall material)
paper (overall material)
velvet (overall material)
metal (overall material)
overall: 5.3 cm x 14.3 cm x 15.5 cm; 2 3/32 in x 5 5/8 in x 6 3/32 in
ID Number
accession number
catalog number
Credit Line
Gift of John William Christopher Draper and James Christopher Draper
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center


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