<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Helvetica;
panose-1:2 11 6 4 2 2 2 2 2 4;}
@font-face
{font-family:Wingdings;
panose-1:5 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
font-size:11.0pt;
font-family:"Calibri",sans-serif;
mso-ligatures:standardcontextual;
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0cm;
margin-right:0cm;
margin-bottom:0cm;
margin-left:36.0pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;
mso-ligatures:standardcontextual;
mso-fareast-language:EN-US;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri",sans-serif;
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:2073192446;
mso-list-type:hybrid;
mso-list-template-ids:1468954182 2082872846 134807555 134807557 134807553 134807555 134807557 134807553 134807555 134807557;}
@list l0:level1
{mso-level-start-at:0;
mso-level-number-format:bullet;
mso-level-text:-;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:"Calibri",sans-serif;
mso-fareast-font-family:Calibri;}
@list l0:level2
{mso-level-number-format:bullet;
mso-level-text:o;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:"Courier New";}
@list l0:level3
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:Wingdings;}
@list l0:level4
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:Symbol;}
@list l0:level5
{mso-level-number-format:bullet;
mso-level-text:o;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:"Courier New";}
@list l0:level6
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:Wingdings;}
@list l0:level7
{mso-level-number-format:bullet;
mso-level-text:\F0B7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:Symbol;}
@list l0:level8
{mso-level-number-format:bullet;
mso-level-text:o;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:"Courier New";}
@list l0:level9
{mso-level-number-format:bullet;
mso-level-text:\F0A7;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-18.0pt;
font-family:Wingdings;}
ol
{margin-bottom:0cm;}
ul
{margin-bottom:0cm;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='font-size:13.0pt'>Dear All<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'>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).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'>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. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'>Over the decades-long life of the project I documented the interpretation of the 19<sup>th</sup>-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.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'>A full description of the Engine is presented in two works available online:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt;font-family:"Helvetica",sans-serif;color:black;mso-ligatures:none;mso-fareast-language:EN-GB'><a href="https://www.sciencemuseum.org.uk/sites/default/files/2023-09/DE2_Technical_Description.pdf"><i><span style='color:blue'>Difference Engine No.2 Technical Description</span></i></a></span><b><span style='font-size:13.0pt'> </span></b><span style='font-size:13.0pt'>(232 pages, 131 illustrations)<o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:1.0cm'><span style='font-size:13.0pt'>Provides a detailed interpretation of Babbage’s design, and documents the technical understanding that informed the successful construction of the working machine.<o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:1.0cm'><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt;font-family:"Helvetica",sans-serif;color:black;mso-ligatures:none;mso-fareast-language:EN-GB'><a href="https://www.sciencemuseum.org.uk/sites/default/files/2023-08/User_Manual_PDF_Vsn_1.1_Final_SEC1.pdf"><i><span style='color:blue'>Difference Engine No.2 User Manual</span></i></a> </span><span style='font-size:13.0pt'>(147 pages, 199 illustrations)<o:p></o:p></span></p><p class=MsoNormal style='margin-left:1.0cm;text-indent:-1.0cm'><span style='font-size:13.0pt'> Documents the practical procedures for operating the Engine safely, setting up a calculation, testing, trouble-shooting, fault-finding, and maintenance including lubrication.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'>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 19<sup>th</sup>-century design drawings. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:13.0pt'>Direct Browser Links: <o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:13.0pt;color:black;mso-ligatures:none;mso-fareast-language:EN-GB'>Technical Description:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt;color:black;mso-ligatures:none;mso-fareast-language:EN-GB'><a href="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</a><o:p></o:p></span></p><p class=MsoNormal><span lang=FR style='font-size:13.0pt;color:black;mso-ligatures:none;mso-fareast-language:EN-GB'>User Manual:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt;color:black;mso-ligatures:none;mso-fareast-language:EN-GB'><a href="https://www.sciencemuseum.org.uk/sites/default/files/2023-08/User_Manual_PDF_Vsn_1.1_Final_SEC1.pdf"><span lang=FR>https://www.sciencemuseum.org.uk/sites/default/files/2023-08/User_Manual_PDF_Vsn_1.1_Final_SEC1.pdf</span></a></span><span lang=FR style='font-size:13.0pt;color:black;mso-ligatures:none;mso-fareast-language:EN-GB'><o:p></o:p></span></p><p class=MsoNormal><span lang=FR style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:14.0pt'>Additional Material<o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt;color:#2F5597'><a href="https://collection.sciencemuseumgroup.org.uk/documents/aa110000003/the-babbage-papers"><span style='color:#2F5597'>The Babbage Papers at the Science Museum:</span></a><o:p></o:p></span></p><ul style='margin-top:0cm' type=disc><li class=MsoListParagraph style='margin-left:0cm;mso-list:l0 level1 lfo1'><span style='font-size:13.0pt'>Digitised archive of Babbage papers including full technical archive and Notebooks. <o:p></o:p></span></li></ul><p class=MsoNormal><span style='font-size:13.0pt'><a href="https://collection.sciencemuseumgroup.org.uk/documents/aa110000003/the-babbage-papers">https://collection.sciencemuseumgroup.org.uk/documents/aa110000003/the-babbage-papers</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><u><span style='font-size:13.0pt;color:#2F5597'><a href="https://www.sciencemuseum.org.uk/objects-and-stories/charles-babbages-difference-engines-and-science-museum"><span style='color:#2F5597'>Charles Babbage’s Difference Engines and the Science Museum | Science Museum</span></a><o:p></o:p></span></u></p><ul style='margin-top:0cm' type=disc><li class=MsoListParagraph style='margin-left:0cm;mso-list:l0 level1 lfo1'><u><span style='font-size:13.0pt'>Short contextual and historical summary. <o:p></o:p></span></u></li><li class=MsoListParagraph style='margin-left:0cm;mso-list:l0 level1 lfo1'><u><span style='font-size:13.0pt'>Links to the <i>Technical Description</i> and <i>User Manual </i>are in Further Reading.<o:p></o:p></span></u></li></ul><p class=MsoNormal><u><span style='font-size:13.0pt'><a href="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</a><o:p></o:p></span></u></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;mso-ligatures:none;mso-fareast-language:EN-GB'>Citation</span><span style='font-size:13.0pt;mso-ligatures:none;mso-fareast-language:EN-GB'>: <o:p></o:p></span></p><p class=MsoNormal style='margin-left:14.2pt;text-indent:-14.2pt'><span style='font-size:12.0pt;mso-ligatures:none;mso-fareast-language:EN-GB'>Swade, Doron, </span><i><span style='font-size:12.0pt'>Charles Babbage's Difference Engine No. 2: Technical Description</span></i><span style='font-size:12.0pt'>. Science Museum, 2023.<o:p></o:p></span></p><p class=MsoNormal style='margin-left:14.2pt;text-indent:-14.2pt;text-autospace:none'><span style='font-size:12.0pt'>Swade Doron, <i>Charles Babbage's Difference Engine No. 2: User Manual</i>. Science Museum, 2023.<o:p></o:p></span></p><p class=MsoNormal style='margin-left:14.2pt;text-indent:-14.2pt;text-autospace:none'><span style='font-size:12.0pt'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:14.2pt;text-indent:-14.2pt;text-autospace:none'><span style='font-size:13.0pt'>Best wishes<o:p></o:p></span></p><p class=MsoNormal style='margin-left:14.2pt;text-indent:-14.2pt;text-autospace:none'><span style='font-size:13.0pt'>Doron Swade</span><span style='font-size:13.0pt;mso-fareast-language:EN-GB'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:13.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt'><o:p> </o:p></span></p></div></body></html>