Difference engine: Difference between revisions

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Revision as of 18:57, 10 April 2024

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[[Alexander John Thompson]] about 1927 built ''integrating and differencing machine'' (13-digit numbers and fifth-order differences) for his table of logarithms "Logarithmetica britannica". This machine was composed of four modified Triumphator calculators.<ref>{{Cite book |url=https://books.google.com/books?id=fH48AAAAIAAJ|title=Logarithmetica Britannica: Being a Standard Table of Logarithms to Twenty Decimal Places |last=Thompson |first=Alexander John |date=1924 |publisher=CUP Archive |isbn=9781001406893 |pages=V/VI, XXIX, LIV–LVI, LXV (archive: pp. 7, 30, 55–59, 68) }} [https://archive.org/stream/in.ernet.dli.2015.285845/2015.285845.Logarithmetica-Britannica#page/n29/mode/1up/search/Integrating+and+Differencing+machine Alt URL]</ref><ref>{{Cite web|url=https://history-computer.com/Babbage/NextDifferentialEngines/Thompson.html|title=History of Computers and Computing, Babbage, Next differential engines, Alexander John Thompson|website=history-computer.com|access-date=2017-09-22}}</ref><ref>{{Cite web|url=http://mechrech.info/publikat/publikat.html#pub70|title=Publikationen|last=Weiss|first=Stephan|website=mechrech.info|pages=160–163|others=''Difference Engines in the 20th Century''. First published in Proceedings 16th International Meeting of Collectors of Historical Calculating Instruments, Sep. 2010, Leiden|access-date=2017-09-22}}</ref>

3[[Leslie Comrie]] in 1928 described how to use the [[Odhner Arithmometer|Brunsviga]]-Dupla calculating machine as a difference engine of second-order (15-digit numbers).<ref name=":5" /> He also noted in 1931 that National Accounting Machine Class 3000 could be used as a difference engine of sixth-order.<ref name=":4" />{{Rp|137–138}}

===Construction of two working No. 2 difference engines===