Hi Doron: Many thanks – and congratulations, on a truly wonderful project, and now this splendid documentation. Cheers Brian — School of Computing, Newcastle University, 1 Science Square, Newcastle upon Tyne, NE4 5TG EMAIL = Brian.Randell@ncl.ac.uk PHONE = +44 191 208 7923 URL = https://www.ncl.ac.uk/computing/staff/profile/brianrandell.html On 02/12/2023, 15:01, "Members" <members-bounces@lists.sigcis.org> wrote: Dear All I am pleased to report that the full technical description of Charles Babbage’s Difference Engine No. 2 has recently been made available online on open access by the Science Museum (London). The Engine was built to Babbage’s original drawings (1847-1849) and completed in 2002. It has 8,000 parts, weighs 5 tonnes, and works as Babbage intended. It is the first of Babbage’s calculating engines to be built in its entirety. Over the decades-long life of the project I documented the interpretation of the 19th-century drawings, the design decisions made in its construction, its assembly, operational debugging, and what was learned from running the Engine for countless live public demonstrations. A full description of the Engine is presented in two works available online: Difference Engine No.2 Technical Description <https://www.sciencemuseum.org.uk/sites/default/files/2023-09/DE2_Technical_Description.pdf><https://www.sciencemuseum.org.uk/sites/default/files/2023-09/DE2_Technical_Description.pdf%3e> (232 pages, 131 illustrations) Provides a detailed interpretation of Babbage’s design, and documents the technical understanding that informed the successful construction of the working machine. Difference Engine No.2 User Manual <https://www.sciencemuseum.org.uk/sites/default/files/2023-08/User_Manual_PDF_Vsn_1.1_Final_SEC1.pdf><https://www.sciencemuseum.org.uk/sites/default/files/2023-08/User_Manual_PDF_Vsn_1.1_Final_SEC1.pdf%3e> (147 pages, 199 illustrations) Documents the practical procedures for operating the Engine safely, setting up a calculation, testing, trouble-shooting, fault-finding, and maintenance including lubrication. The two documents are free-standing i.e. relevant drawing-excerpts are embedded in the text so that understanding does not, for the most part, rely on reference to the full 19th-century design drawings. Direct Browser Links: Technical Description: https://www.sciencemuseum.org.uk/sites/default/files/2023-09/DE2_Technical_D... <https://www.sciencemuseum.org.uk/sites/default/files/2023-09/DE2_Technical_Description.pdf><https://www.sciencemuseum.org.uk/sites/default/files/2023-09/DE2_Technical_Description.pdf%3e> User Manual: https://www.sciencemuseum.org.uk/sites/default/files/2023-08/User_Manual_PDF... <https://www.sciencemuseum.org.uk/sites/default/files/2023-08/User_Manual_PDF_Vsn_1.1_Final_SEC1.pdf><https://www.sciencemuseum.org.uk/sites/default/files/2023-08/User_Manual_PDF_Vsn_1.1_Final_SEC1.pdf%3e> Additional Material The Babbage Papers at the Science Museum: <https://collection.sciencemuseumgroup.org.uk/documents/aa110000003/the-babbage-papers><https://collection.sciencemuseumgroup.org.uk/documents/aa110000003/the-babbage-papers%3e> * Digitised archive of Babbage papers including full technical archive and Notebooks. https://collection.sciencemuseumgroup.org.uk/documents/aa110000003/the-babba... <https://collection.sciencemuseumgroup.org.uk/documents/aa110000003/the-babbage-papers><https://collection.sciencemuseumgroup.org.uk/documents/aa110000003/the-babbage-papers%3e> Charles Babbage’s Difference Engines and the Science Museum | Science Museum <https://www.sciencemuseum.org.uk/objects-and-stories/charles-babbages-difference-engines-and-science-museum><https://www.sciencemuseum.org.uk/objects-and-stories/charles-babbages-difference-engines-and-science-museum%3e> * Short contextual and historical summary. * Links to the Technical Description and User Manual are in Further Reading. https://www.sciencemuseum.org.uk/objects-and-stories/charles-babbages-differ... <https://www.sciencemuseum.org.uk/objects-and-stories/charles-babbages-difference-engines-and-science-museum><https://www.sciencemuseum.org.uk/objects-and-stories/charles-babbages-difference-engines-and-science-museum%3e> Citation: Swade, Doron, Charles Babbage's Difference Engine No. 2: Technical Description. Science Museum, 2023. Swade Doron, Charles Babbage's Difference Engine No. 2: User Manual. Science Museum, 2023. Best wishes Doron Swade