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Development // Adders // Keyboard Adding Machines // Future of Computing

Many of the nineteenth-century calculators were simple instruments called “adders,” which had no internal mechanism to compute mathematically, but relied on movable parts to figure and record the result of such computations.  The first calculator marketed in Harper’s Weekly was, in fact, an adder called the Fowler Adding Machine.  The small text-only advertisement appeared in the issue of September 26, 1863, the year it was patented by George B. Fowler.  Specifically, it was a slide adder, inspired by the abacus and comprised of enumerated slide bars with holes or notches (instead of beads and strings) fitted inside a flat rectangular case and moved with a stylus.  Six years later, an item in the “Home and Foreign Gossip” column of the February 13, 1869 issue lauded the Fowler Adding Machine’s simplicity of design and accuracy of results.  After joking that the Board of Education could now eliminate math classes in the public schools, the columnist remarked seriously that the “adding machine” would be of great value to “book-keepers, accountants, and business-men generally.” 

An adder with a very different look was Webb’s Adding Machine, which was made of two enumerated rotating disks (one larger, one smaller) encased as a unit.  The product’s advertisement in the February 13, 1869 issue included endorsements from Vice President Schuyler Colfax, evangelist Henry Ward Beecher, Mayor A. Oakey Hall of New York City, and others.  It also got a promotional boost the next week in the publication’s “Home and Foreign Gossip” column.  An illustration in an 1891 ad revealed each disk in the later model Webb Adder to be more distinct.  A third style of adder was a circular model manufactured by William Furniss.  His product’s ad text in the January 8, 1876 issue promised “Rapid Addition!” 

Harper's Weekly References
1) September 26, 1863, p. 622, col. 3
ad, Fowler Adding Machine (1st ad)

2) February 13, 1869, p. 107, col. 4
news item, Fowler Adding Machine

3) February 13, 1869, p. 112, col. 4
illustrated ad, Webb’s Adding Machine

4) February 27, 1869, p. 135, col. 3
news item, Webb’s Adding Machine

5) June 6, 1891, p. S3, col. 1
illustrated ad, adder, Webb Adder

6) January 8, 1876, p. 35, col. 3
illustrated ad, “Rapid Addition” adder

Sources Consulted

“Calculating Machines.”

Redin, James.  “A Brief History of Mechanical Calculators.”

“Webb’s Patent Adder and Talley Board,” Scientific American (1869), reprinted on “American Artifacts:  Articles Online.”

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Development // Adders // Keyboard Adding Machines // Future of Computing





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