Returning visitors can check for updates here.

Thu Jul 13 15:27:13 2017
Linked to Marie Stefanova's translation of the Introduction.
Linked to Kate Osipova's translation of the Fenymann article.
Thu Sep 3 17:43:00 2015
New HTML5 version of abacus website online.
Sun Jan 11 09:54:17 2015
Replaced homepage feature image/article about Khipu with Tokyo abacus contest. Updated history by moving detailed articles about Salamis and Exchequer into the appropriate era sections.
Thu Dec 25 19:46:14 2014
Updated Michael Mode's abacus. Link this to the home page under DIY Abaci.
Sun Nov 29 20:13:40 2014
Re-freshed the abacus anatomy image (using the online image re-sizer at Reshade.com) in the Introduction page. The bead orientation is now correct for a zeroed abacus. The old image had the upper beads against the beam.
Sun Nov 23 00:31:04 2014
Re-freshed the timeline image, and made larger images (using the online image re-sizer at Reshade.com) for the three eras of computing devices in the History page.
Sat Nov 8 12:29:51 2014
Updated the main page by moving the Stephenson's Ancient Computers article and the counting board video to the History page. Added bylines to the contest and Feynman excerpts on the main page. In the History page, moved the Roman hand-abacus information from the main section to the sidebar with a link to Stephenson's main article.
Sun Sep 14 16:29:27 2014
Updated History page with links to History of Mathematics, Han Dynasty and Hindu-Arabic numeral system.
Thu Sep 11 01:22:21 2014
Started updating Roman Hand Abacus page.
Sat Aug 30 00:36:57 2014
Updated introduction page. Moved "The Abacus Today" to the History page. Changed paragraph (captions subclass) to H3 tags. Made an image for the Hindu Arabic Numbering system in history page.
Sun Aug 24 23:22:30 2014
Updated source code page with new HTML 5 and CSS and moved link to homepage footer. Linked obsolete links to Sun's 1996 Alpha Java Programming Contest to archive.org. Moved LEGO and popsicle-stick abacus links from footer to "DIY" sidebar of homepage; added link to IBM molecular abacus on archive.org.
Fri Aug 22 16:09:00 2014
Updated Acknowledgements and Thanks with new HTML5 and CSS. The teaching plan and links to building a LEGO abacus and a popsicle-stick abacus from the old "For Teachers" page was combined into the FAQ. The math and science links were moved to the index page footer.
Sat Aug 16 22:23:57 2014
Updated LEGO abacus and Popsicle-stick abacus pages with new HTML5 and CSS.
Sat Aug 16 10:22:03 2014
Copied list of books and cover thumbnails about the abacus from Further Resources page to FAQ (new section listing books) and added a book cover to Kojima's Advanced Abacus book. I'll probably move all the links from the Further Resources page to the footer of the main page.
Sat Aug 9 22:59:37 2014
New HTML 5 CSS look for the Feynman vs. The Abacus excerpt. Updated with links to Richard Feynman Official Website and a quotes site.
Sun Aug 3 00:43:02 2014
New HTML 5 CSS look for the Abacus Contest article. Updated with the Burroughs Electric Adding Machine information.
Sat Jul 12 15:59:36 2014
New HTML 5 CSS look for the History page. Updated with information about the Exchequer.
Sun Jul 06 00:00:34 2014
Started working on new HTML 5 CSS look.
Sun 06 Apr 2014 03:53:36 PM EDT
Added sidebar about Hindu-Arabic numbering system and Fibonacci's Liber Abaci to History page.
Sat 10 Aug 2013 10:16:50 PM
Broken links on the History, For Teachers pages linked to the Wayback Machine archives.

2008-2010

Tue Nov 02 16:48:19 2010
An Japanese Soroban with accelerometer and sound support.
Wed Aug 11 07:59:56 2010
Linked to Using a Counting Board by Steve Stephenson, on the history page.
Wed Aug 11 07:59:56 2010
Linked to Steve Stephenson's article Ancient Computers
Tue Oct 20 16:00:47 2009
Updated URLs with "sciam" to "scientificamerican".
Tue Jul 29 16:20:25 2008
An iPhone abacus is now available. Sadly, it's not oriented properly.
Sun Apr 06 22:19:47 2008
Added a link to Steve Stephenson's Roman abacus website.

2006-2007

Thu Nov 01 00:31:51 2007
Created a PDF document of all the images files from the Lee Abacus manual. I'm not pleased with the quality of the conversion. I think I'm going to have to make higher resolution scans of the pages and retry the conversion.
Mon Dec 18 16:40:28 2006
David Bagley emailed me to announce the Java version of the Lee abacus.
Sun Jun 04 13:05:55 2006
I received an email from Edward Barnique, announcing his new book “EasyAbacus”, written primarily for students in grades 4-6, but may be used by anyone wishing to learn the basics.
Sat May 20 21:55:34 2006
Added my Abacus.ldr LDRAW model file of the LEGO abacus. I designed the model using Bricksmith (Mac version).

2005

Fri May 13 18:12:50 2005
Put Michael Mode's abaci photos online.
Mon Apr 25 19:05:37 2005
The link to the AMS review of the Universal History of Books was no longer available for free. I have now linked to a HTML copy in Google's Cache.
Sun Apr 10 22:17:31 2005
More links to Wikipedia entries: updated David B. Kelley's analysis with links to Mayan numerals and the Mayan calendar.
Sun Mar 2012:42:16 2005
Wikipedia article about Roman embassies to China linked in the History page as a possible way that Roman culture was absorbed by China.
Sat Mar 19 02:34:07 2005
Byrne's edition of Euclid linked in the "For Teachers" section.
Fri Mar 11 15:09:05 2005
Abacus: Mystery of the Bead by Totton Heffelfinger & Gary Flom.

2004

Mon Nov 08 08:43:39 2004
Put a “Get Firefox” button in anticipation of Firefox 1.0 release on Nov. 9th.
Sun Sep 19 12:22:27 2004
Changed the "upgrade browser" link on the main page from Mozilla to Firefox.
Fri Jul 16 23:39:13 2004
Spanish translation by Jonathan Abdiel Gonzalez Valdebenito: The addition instructions translated.
Tue Jun 08 22:56:24 2004
Spanish translation by Jonathan Abdiel Gonzalez Valdebenito: The history has been translated.
Mon Jan 26 12:48:47 2004
Portuguese translation by Antonio V. Fernandes: The index and the introduction have been translated.
Mon Thu Jan 22 19:51:12 2004
Bagley's OCR of Lee's Abacus scans.
Mon Jan 12 00:29:26 2004
Moved the link to Bagley's abacus on the main page up just after the history link. Site was offline for most of last night as the servers had to be shutdown after a water pipe burst due to the extreme cold. The Spanish translation page is getting approximately 10 hits per day from users searching Google in spanish.

2003

Wed Dec 31 18:38:56 2003
Spanish translation by Jonathan Abdiel Gonzalez Valdebenito: The index and the introduction have been translated.
Wed Dec 31 12:31:51 2003
Converted Kelley analysis from an image to HTML.
Fri Dec 19 20:50:52 2003
Added three new photos: 2 photos of the Tomoe soroban and 1 photo of three abaci together.
Fri Dec 19 00:57:16 2003
Added a link to the Curta calculator. More late-night hacking.
Thu Dec 18 23:09:13 2003
Christmas vacation begins with some abacus photography. The first image after 4 hours of Photoshop goes on the title page. Added a better photo of the Lee abacus and a new photo of the Tomoe soroban to the Photo page. For some reason, abaci photograph better standing upright-- a very unnatural position.
Wed Dec 17 01:54:29 2003
The Controversy about da Vinci's Adding Machine.
Tue Dec 09 23:33:39 2003
During some late-night hacking last night, the addition of some HTML comments caused most of the centre column of the index page to not render. That was rather embarrassing-- no more hacking after midnight.
Tue Dec 09 00:40:42 2003
Fixed a typo about the 3-column abacus counting up to 199 instead of 999. And a few other typos here and there.
Sun Dec 07 00:32:12 2003
Added a screenshot to the main page showing how a proper CSS browser should render pages.
Mon Dec 01 10:01:24 2003
Cut-over to the new CSS pages.
Added links to cuneiform and ancient Mesopotamia in the Khipu article.
Sun Nov 30 14:27:17 2003
CSS overhaul is nearly completed.
Thu Nov 27 18:42:09 2003
Added a link to Roman numerals on the Roman hand-abacus page.
Tue Nov 25 14:27:38 2003
Added a link to the acrophonic number system used on the Salamis Tablet.
Fri Nov 21 18:08:32 2003
Experimenting with converting the entire site to use CSS. Note that you will need a modern browser like IE6, Opera or Mozilla to view the pages correctly. Comments are welcome.
Thu Nov 20 18:11:30 2003
Added a new article from Time, Lost Tribes, Lost Knowledge by Eugene Linden.
Wed Oct 22 08:01:19 2003
favicon now displayed for all pages; updated "For Teachers" page with new look. It's about time!.
Tue Oct 21 00:08:44 2003
Graphed access statistics.
Sat Oct 18 12:28:08 2003
New section on site access statistics.
Sat Oct 18 02:33:05 2003
New banner.
Fri Sep 19 15:14:41 2003
Added a new section with a New York Times article on the Incan khipu and a link to another article, Talking Knots of the Incas; also linked to both in the History page.
Wed Sep 17 10:23:35 2003.
Added a link to da Vinci's Calculator. NOTE: Some pages on that site may not appropriate for children, but the linked page is OK.
Sun Aug 03 00:58:40 2003
Added a link to abacus entry on The Wikipedia.
Wed Jul 30 13:25:46 2003
Added a new section with high-resolution photos of my abacus collection.
Tue Jul 29 01:22:18 2003
Added a photo of the PalmOS Soroban to Additional Resources and re-arranged some text and images.
Wed Jun 04 18:29:24 2003
Added another photo to Roman hand-abacus page. Updated LEGO abacus page with the new look.
Tue May 27, 2003
Selected by ScientificAmerican.com as a winner of the 2003 Sci/Tech Web Awards.
Tue Feb 04 16:50:21 2003
Index page has new look.
Mon Feb 03 20:34:08 2003
Link to the Cranmer Abacus available for purchase from the American Printing House.
Mon Feb 03 17:26:19 2003
"New look" for Introduction, Lee Abacus, Schoty, Contest, Feynman.
Sun Feb 02 20:39:21 2003
Updated abacus history page with "the new look"; eventually all the pages will sport this look.
Sat Feb 01 06:21:19 2003
Corrected attribution for photo of Roman hand-abacus.

2002

Tue Dec 31 15:24:23 2002
New photo and updated information about the Salamis Tablet.
Tue Dec 31 15:20:20 2002
Sarat Chandran and David A Bagley's Java abacus now supports the schoty (albeit sideways).
Mon Dec 02 22:50:17 2002
Added The Japanese Abacus Math School to the FAQ.
Mon Dec 02 22:15:32 2002
PalmOS soroban in Further Resources.
Fri Nov 22 08:49:03 2002
Edward Barnique's Popsicle-stick Abacus in Further Resources.
Tue Oct 29 19:46:11 2002
Photo of Roman hand-abacus.
Tue Oct 22 18:05:27 2002
Square and cubic roots on the Lee Abacus.
Sat Oct 05 12:14:51 2002
New addition: Feynman vs. the Abacus.
Sat Oct 05 09:55:44 2002
Some minor editing and re-organization of the Introduction and History.
Sat Sep 21 21:48:03 2002
New addition: The Schoty.
Tue Sep 17 10:29:26 2002
New addition: Roman Hand-Abacus.
Mon Sep 02 11:43:13 2002
Abacus watches.
Tue Aug 20 09:56:39 2002
Updated link to the Nepohualtzitzin, an Aztec abacus.
Sat Aug 10 23:44:06 2002
Email correspondence from Maria Jette, the soprano.
Fri Apr 12 03:30:13 PM 2002
Sarat Chandran and David A Bagley have a really wonderful Java abacus that can be switched between Japanese and Chinese version and includes a built-in interactive tutorial that teaches counting. An X11 version and a MS Windows version are also available.
Fri April 05 10:15:36 AM 2002
After receiving email from Stella Maris Pusino, a journalist of the cultural supplement of The Pais, from Uruguay, telling me that the Babelfish Spanish translation links were broken, I switched over to the Google translation service.

2001

Tue Nov 06 18:44:17 2001
Added a link to William Kahan's homepage at UC Brekeley with many interesting papers on mathematics.
Wed 24 Oct 2001 20:26:46 EDT
Link to abacus classroom study-plan: updated.
Sun Mar 25 09:56:37 EST 2001
Resources For Teachers: collected bits of information from other pages into one place.
Sat Mar 24 08:03:12 EST 2001
FAQ: Added new question, "Who invented the abacus?". I typically receive this question around Spring time.
Fri Mar 16 12:21:09 EST 2001
Source Code: Fixed a typo that prevented nobead.gif from being downloaded and the example applet code from being displayed [thanks Ema!].
Mon Jan 1 17:00:50 EST 2001
Source Code: Instructions for running the applet locally have been improved. Let me know if they're still unclear.

2000

Tue Nov 21 19:59:54 EST 2000
The Lee Kai-chen Abacus: I've finally gotten around to scanning the book from which the addition and subtraction instructions are taken. Chapter 4 and 5 show multiplication and division.
Tue Nov 14 16:58:39 EST 2000
FAQ: Updated the FAQ with 1. a new question about schools teaching the abacus; 2. a new pointer for teachers that has a lesson plan for teaching the abacus and 3. some shops in Toronto where abaci may be purchased.
Tue Nov 13 20:10:30 EST 2000
Eric Harshbarger's LEGO abacus: You can also see his other remarkable creations like the LEGO Mona Lisa and a LEGO table.
Nov 12 22:35:57 EST 2000
Correspondence: Just a small sample of email I have had the pleasure to receive, over the years, about the abacus pages.