The Webb Adder, or Webb's Adder, is one of the first highly successful adders. It was invented by Charles Henry Webb, who was a poet and writer. The first model of the adder was marketed from 1869, and from 1890 onwards a new redesigned model was sold. From about 1900 other manufacturers sold virtually identical copies of this second model, presumably under licence. Mine must be one of those copies, as it has no brand name, patent number, or serial number anywhere. It may in fact be one that was sold under the "Lightning Calculator" name by The Book-Keeper Publishing Company Ltd., in Detroit, Michigan.
The Webb Adder has two number wheels connected by a simple but effective carry mechanism. The large number wheel on the right counts from 00 to 99, while the left wheel counts from 0 to 49, allowing for totals up to 4999.
The right wheel has 100 evenly spaced small holes, and they line up with the numbers 00 to 99 etched into the cover plate. Simply put a stylus in the appropriate hole and turn the wheel clockwise until your stylus hits the small tab at the right, very similar to dialling an old-fashioned rotary telephone dial. The left wheel has only 10 holes exposed (the other 40 are hidden behind the front cover), so any number from 0 to 999 can be added to the total.
To clear the total, find the hole in the large wheel that is marked on the wheel itself with a 0. Some versions have an image of a pointing hand etched in the wheel there. Dialling that hole resets the right wheel to 00. The left wheel has an extra hole set closer to the centre which you can dial in to reset it to 0. On my adder this extra hole is connected up to the outer hole for zero to form a small slot, so that when you dial it the stylus will slide outwards and into the path of the tab. Other versions of the adder have a separate tab for the reset hole.
The carry mechanism uses stored energy, so that moving the large wheel from 98 to 99 takes the same amount of effort as moving it from 99 to 00. There is a cam wheel under the large number wheel arranged so that as the wheel turns from 00 to about 30, a latch is pushed outwards against a spring until it catches the next tooth of a gear under the small number wheel. When the large wheel moves from 99 to 00, the cam wheel allows the latch to be released, and the spring pulls it back, turning the small wheel one step.
The adder was invented by Charles Henry Webb, who was a journalist, and humorist. Apart form the adder, he also invented a machine for loading cartridges (patented in 1874, used by Remington) and improvements in extracting precious metals from ore ( US 768,319, GB 1902 24,417).
Here's a video where I demonstrate how the Webb Adder works and show its insides.
Here are some articles about Charles Henry Webb (1834-1905).
Sunbeams, the personal announcements section of The Sun
(1869-06-05, The sun, New York)
(1871-03-17, Sacramento Daily Union)
Charles H. Webb
(1873-10-25, The Cambridge Chronicle)
C. H. Webb, - "John Paul", his self-penned biography entry.
(1873, A Manual of American Literature)
WEBB, Charles Henry, mini-biography.
(1891, Library of American Literature)
The Late Charles Henry Webb - "John Paul", Obituary.
(1905-06-04, The New York Times)
In Old Bohemia, part of article in which Webb is described
(1908-03, The Pacific Monthly)
WEBB, Charles Henry, mini-biography.
(1932, Nelson's Encyclopedia)
WEBB, CHARLES HENRY, biography.
(1936, Dictionary of American Biography)
Here are some articles about the Webb Adder.
A Snake Fight
(1869-02-25, Sacramento Daily Union)
A Practical Adding-Machine
(1869-07, Bankers Magazine)
Personal Intelligence, the society announcements section of The Sun
(1869-11-02, The sun, New York)
Mr Webb's Adder
(1870-08-18, Hawkes Bay Times, New Zealand)
(1890-12-10, Zeitung fur Landwirthschaft)
Seal v. Beach
(1902-04, Federal Reporter)
Here are various advertisements for the Webb Adder, both the first and second model.
|Patent||Filing date||Publish date||Name||Description|
|US 75,322||10-03-1868||10-03-1868||C. H. Webb||Improvement in Adding-Machines (Model 1 Webb Adder)|
|US 414,959||28-04-1888||12-11-1889||Charles Henry Webb||Adding-Machine (Model 2 Webb Adder)|
|US 414,335||10-07-1889||05-11-1889||Lester C. Smith (assigned to Charles Henry Webb)||Adding-Machine (improved carry mechanism for the Model 2 Webb Adder)|
|US 465,120||25-06-1888||15-12-1891||Charles Henry Webb||Adding-Machine (Webb's Ribbon Adder)|
|US 1,263,244||27-04-1916||16-04-1918||John L. Herring||Webb Adder with adjustable offset|
Detlev Bölter has pictures of the Webb Adder, including its insides showing the mechanism.
Rechnen ohne Strom's page has both models of Webb Adder as well as Herring's Computing machine.
Rechnerlexikon's Webb Adder page, and their page on the Nestler and Roesler and Herring Computing Machine clone.
National Museum of American History has a model 2 Webb Adder, a second model 2, a third model 2, as well as a model 1, a modified model 1, and a Webb Ribbon Adder.
Rechenwerkzeug has some nice pictures of the adder.
Wikipedia's entry for Charles Henry Webb.
© Copyright 2017 Jaap Scherphuis, mechcalc a t jaapsch d o t net.