Difference engine: Difference between revisions

Revision as of 21:21, 2 July 2024

Revision as of 21:24, 2 July 2024

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American [[George B. Grant]] started working on his calculating machine in 1869, unaware of the works of Babbage and Scheutz (Schentz). One year later (1870) he learned about difference engines and proceeded to design one himself, describing his construction in 1871. In 1874 the Boston Thursday Club raised a subscription for the construction of a large-scale model, which was built in 1876. It could be expanded to enhance precision and weighed about {{convert|2000|lb|kg}}.<ref name=":4" /><ref>{{Cite web|url=http://history-computer.com/Babbage/NextDifferentialEngines/Grant.html|title=History of Computers and Computing, Babbage, Next differential engines, George Grant|website=history-computer.com|access-date=2017-08-29}}</ref><ref>{{Cite book|url=https://archive.org/details/greatcentenniale00sandrich|title=The Great Centennial Exhibition Critically Described and Illustrated|last=Sandhurst|first=Phillip T.|date=1876|publisher=P. W. Ziegler & Company|pages=[https://archive.org/details/greatcentenniale00sandrich/page/423 423], 427}}</ref>

[[Christel Hamann]] built one machine (16-digit numbers and second-order differences) in 1909 for the "Tables of [[Julius Bauschinger|Bauschinger]] and Peters" ("Logarithmic-Trigonometrical Tables with eight decimal places"), which was first published in Leipzig in 1910. It weighed about {{convert|40|kg|lb}}.<ref>{{Cite web|url=https://web.archive.org/web/20120225033434/http://history-computer.com/Babbage/NextDifferentialEngines/Hamann.html | title=History of Computers and Computing, Babbage, Next differential engines, Hamann|website=history-computer.com| archive-url=https://web.archive.org/web/20120225033434/http://history-computer.com/Babbage/NextDifferentialEngines/Hamann.html|access-date=2017-09-14| archive-date=2012-02-25}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=vD7PAAAAMAAJ|title=Logarithmisch-trigonometrische Tafeln mit acht Dezimalstellen, enthaltend die Logarithmen aller Zahlen von 1 bis 200000 und die Logarithmen der trigonometrischen Funktionen f"ur jede Sexagesimalsekunde des Quadranten: Bd. Tafel der achtstelligen Logarithmen aller Zahlen von 1 bis 200000|last1=Bauschinger|first1=Julius|last2=Peters|first2=Jean|date=1958|publisher=H. R. Engelmann|pages=Preface V–VI}}</ref><ref>{{Cite book|url=https://archive.org/details/logarithmischtri01bausuoft|title=Logarithmisch-trigonometrische Tafeln, mit acht Dezimalstellen, enthaltend die Logarithmen aller Zahlen von 1 bis 200000 und die Logarithmen der trigonometrischen Funktionen für jede Sexagesimalsekunde des Quadranten. Neu berechnet und hrsg. von J. Bauschinger und J. Peters. Stereotypausg|last1=Bauschinger|first1=Julius|last2=Peters|first2=J. (Jean)|date=1910|publisher=Leipzig W. Englemann|others=Gerstein - University of Toronto|pages=Einleitung VI|language=de}}</ref>

[[Burroughs Corporation]] in about 1912 built a machine for the [[HM Nautical Almanac Office|Nautical Almanac Office]] which was used as a difference engine of second-order.<ref name=":5">{{Cite journal|last=Comrie|first=L. J.|date=1928-03-01|title=On the application of the BrunsvigaDupla calculating machine to double summation with finite differences|bibcode=1928MNRAS..88..447C|journal=Monthly Notices of the Royal Astronomical Society|volume=88|issue=5|pages=451, 453–454, 458–459|doi=10.1093/mnras/88.5.447|issn=0035-8711|via=[[Astrophysics Data System]]|doi-access=free}}</ref>{{Rp|451}}<ref>{{Cite book|url=https://archive.org/stream/moderninstrument00horsuoft#page/127/mode/1up/search/hudson|title=Modern instruments and methods of calculation : a handbook of the Napier Tercentenary Exhibition|last1=Horsburg|first1=E. M.|date=1914|___location=London|publisher=G. Bell|pages=127–131}}</ref> It was later replaced in 1929 by a Burroughs Class 11 (13-digit numbers and second-order differences, or 11-digit numbers and <nowiki>[at least up to]</nowiki> fifth-order differences).<ref>{{Cite journal|last=Comrie|first=L. J.|date=1932-04-01|title=The Nautical Almanac Office Burroughs machine|bibcode=1932MNRAS..92..523C|journal=Monthly Notices of the Royal Astronomical Society|volume=92|issue=6|pages=523–524, 537–538|doi=10.1093/mnras/92.6.523|issn=0035-8711|via=[[Astrophysics Data System]]|doi-access=free}}</ref>

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The printer's primary purpose is to produce [[Stereotype (printing)|stereotype]] plates for use in printing presses, which it does by pressing type into soft plaster to create a [[flong]]. Babbage intended that the Engine's results be conveyed directly to mass printing, having recognized that many errors in previous tables were not the result of human calculating mistakes but from slips in the manual [[typesetting]] process.<ref name="Campbell-Kelly 2004" /> The printer's paper output is mainly a means of checking the engine's performance.

In addition to funding the construction of the output mechanism for the Science Museum's difference engine, [[Nathan Myhrvold]] commissioned the construction of a second complete Difference Engine No. 2, which was on exhibit at the [[Computer History Museum]] in [[Mountain View, California]] from May 2008 to January 2016.<ref name="CHM Press Releases" /><ref>{{Cite web |url=http://www.computerhistory.org/exhibits/babbage/ |title=The Babbage Difference Engine No. 2 |publisher=Computer History Museum |access-date=2018-10-26 }}</ref><ref name="chm2">{{cite web |author-link=Daniel Terdiman |last=Terdiman |first=Daniel |date=April 10, 2008 |title=Charles Babbage's masterpiece difference engine comes to Silicon Valley |url=https://www.cnet.com/culture/charles-babbages-masterpiece-difference-engine-comes-to-silicon-valley/ |work=[[CNET News]]}}</ref><ref>{{Cite web |last=Noack |first=Mark |title=Computer Museum bids farewell to Babbage engine |url=https://www.mv-voice.com/news/2016/01/29/computer-museum-bids-farewell-to-babbage-engine |access-date=2022-07-10 |website=Mv-voice.com |date=29 January 2016 }}</ref> It has since been transferred to [[Intellectual Ventures]] in [[Seattle]] where it is on display just outside the main lobby.<ref>{{Cite web |last=Boyle |first=Alan |date=2016-09-11 |title=Inside the invention factory: Get a peek at Intellectual Ventures' lab |url=https://www.geekwire.com/2016/inside-intellectual-ventures-lab/ |access-date=2024-04-21}}</ref><ref>{{Cite web |title=Intellectual Ventures on LinkedIn: #ivlab #coolscience |url=https://www.linkedin.com/posts/intellectual-ventures_ivlab-coolscience-activity-6568159438295965696-tGHx |access-date=2024-04-21 |website=www.linkedin.com |language=en}}</ref><ref>{{Cite web |last=Ventures |first=Intellectual |date=September 1, 2016 |title=IV's Favorite Inventions: The Babbage Machine |url=https://www.intellectualventures.com/buzz/insights/ivs-favorite-inventions-the-babbage-machine#:~:text=Visit%20the%20Intellectual%20Ventures%20Lab,in%20the%20IV%20Lab%20foyer. |access-date=March 24, 2024 |website=Intellectual Ventures}}</ref>

== Operation ==