Editing Slide calculator

{{short description|Mechanical calculator}}
[[file:Addiator.jpg|thumb|An Addiator Duplex, featuring an addition side]]
{{multiple image|total_width=200
| footer = Two types of Addiators
| image1 = Modern Addiator.jpg
| alt1 = Picture of Addiator
| caption1 = Addition + subtraction, single window
| image2 = Addiator negative values.jpg
| alt2 = Picture showing result of 5 − 8 = −3
| caption2 = Negative value handling in complementary window
}}

A '''slide calculator''', also known as an '''Addiator''' [[Generic trademark|after the best-known brand]], is a [[mechanical calculator]] capable of addition and subtraction, once made by [[Addiator Gesellschaft]] of [[Berlin]], [[Germany]]. Variants of it were manufactured from 1920 until 1982. The devices were made obsolete by the [[electronic calculator]].

== Design ==
{{unsourced|section|date=October 2023}}
The Addiator is composed of sheet-metal sliders inside a metal envelope, manipulated by a stylus, with an innovative carry mechanism, doing ''subtract ten, carry one'' with a simple stylus movement. Some types of Addiators can also handle negative numbers (with a complementary bottom window or by providing a subtraction mode on the back side of the device).

The Addiator also handles non-decimal measurements, like feet and inches, or pre-decimalization [[pounds, shillings, and pence]]. Addition and subtraction require different "screens", handled by turning the instrument over, or flipping a front panel, or, later, by extended sliders and an extra lower panel. Although not always advertised (e.g., the [[Magic Brain Calculator]] mentions "add, subtract, multiply" on its front plate), procedures exist for multiplication (by repeated addition or by individual digit multiplications) and division (e.g., by repeated subtraction, or use of additions combined with [[complementary numbers]]).

More expensive versions have a built-in [[slide rule]] on the back.

== History ==
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Sometime between 1666 and 1675, French polymath [[Claude Perrault]] invented the first slide calculator, called ''Abaque rhabdologique'' (a [[Rabdology|rabdological]] [[abacus]]), when he needed to do a lot of calculations while working as an [[architect]].

About three decades later, around 1700 or shortly after, French businessman and amateur mathematician César Caze simplified Perrault's design and adapted it to counting money, getting a privilege (patent) in 1711. However, neither of these devices implemented a carry mechanism.

In 1845, German musician and amateur mechanic Heinrich Kummer, who was living in St. Petersburg, saw a mechanical calculator of a different design made by [[Hayyim Selig Slonimski]], and in the next year borrowed the idea of its carry mechanism to greatly improve Caze's device, leading to the modern variant of the slide calculator.

===Addiator===
In 1889, Louis-Joseph Troncet successfully commercialized the Addiator,<ref>{{cite news |url=https://www.newspapers.com/article/the-berkshire-eagle-vintage-calculator-c/136988519/ |title=Vintage calculator called an 'addiator' |first=Glenn |last=Erardi |newspaper=[[The Berkshire Eagle]] |location=[[Pittsfield, Massachusetts]] |page=E3 |date=May 3, 2003 |accessdate=December 17, 2023 |via=newspapers.com}}</ref> which became one of the most popular calculators of its kind, and the name is often used to refer to the type generally.
<ref>{{cite news |last1=Anton |first1=Mike |title=Calculator |url=https://ccalculators.co.uk |access-date=28 September 2021}}</ref>
Addiators appeared in newspaper advertisements as early as 1921, listed at a price of {{GBP|4|1921}} in the ''[[Daily Record (Scotland)|Daily Record]]'' of Scotland.<ref>{{cite news |url=https://www.newspapers.com/article/daily-record-addiator-pocket/136987207/ |title=Addiator Pocket |newspaper=[[Daily Record (Scotland)|Daily Record]] |location=[[Glasgow]] |page=19 |date=November 18, 1921 |accessdate=December 17, 2023 |via=newspapers.com}}</ref> As of 1968, Addiators were advertised in American newspapers starting at $3.98 each {{USDCY|3.98|1968}}.<ref>{{cite news |url=https://www.newspapers.com/article/danville-register-and-bee-does-1001-jobs/136986645/ |title=Does 1001 Jobs $150 Electrics Won't For 1/25 the Cost |newspaper=[[Danville Register & Bee]] |location=[[Danville, Virginia]] |page=Family Weekly pg. 7 |date=July 7, 1968 |accessdate=December 17, 2023 |via=newspapers.com}}</ref>

== See also ==
* {{annotated link|Napier's bones}}
* {{annotated link|History of computing hardware}}
* {{annotated link|Pascaline}}

==References==
{{reflist}}

== External links ==
{{commons category|Addiator}}

* [http://www.vintagecalculators.com/html/addiator.html 'Addiator' type calculators] at Vintage Calculators Web Museum
* [http://www.addiator.de Addiator museum]
* [http://www.calculators.de Calculator museum]
* [http://www.peterkernwein.de/Rechengeraete-Sammlung/addiator_universal.htm  Addiators and many other calculators] (in German)
* [http://www.tcocd.de/index.shtml Collection of calculating devices]
* [http://www.rechnerlexikon.de/en/artikel/Addiator Addiator] at Rechnerlexikon (in German)
* [http://www.computercollector.com/archive/hhmechcalc/ Addiator photos and manuals hosted at www.computercollector.com]
* [http://tinas-sliderules.me.uk/Slide%20Rules/Addiators.html Addiator photos]
* [http://calculating.wordpress.com/2012/02/06/the-hexadat-programmers-and-computer-engineers-calculator/ Addiator Hexadat Programmers Calculator]
* [https://issuu.com/keesnagtegaal/docs/catalogue-2015-1.3 A catalog showing photographs of dozens of different models]
* [https://www.youtube.com/watch?v=6l3zCWL1y3Q Magic Brain: Last Gasp of the Mechanical Calculator] via [[YouTube]]

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[[Category:Mechanical calculators]]