@AlexBell,
The idea is to put html "{-epub-writing-mode: vertical-rl}" into the css file of an (DRM free) epub. On the reader choose "Gothic MB101" as font face. Page forward by touching the top of the screen and backward by touching the bottom of the screen.
I add an example epub from today's "Some of Our Latest Books" list of
http://www.gutenberg.org/ which is modified by me so that you can test it.
If you need more details on how to make it yourself:
Decompress an epub (it is a zip file) and then find and open the css file (if there are more css files you have to decide on a case by case base which to choose). Add the line
Code:
html {-epub-writing-mode: vertical-rl}
to the css file. If there is already a "html {...}" entry then add "-epub-writing-mode: vertical-rl" to it.
After that re-compress the whole content and copy it to the reader.
The important point in compressing is that the file "mimetype" has to be the first file in the zip-file and must not be compressed. Most tutorials recommend 7-zip for this, but it does not work for me. I use info-zip, which can be downloaded here (
http://stahlworks.com/dev/index.php?tool=zipunzip). I add a batch file below that makes the task easier (on Windows). Copy it to your computer. If you drag and drop the "mimetype" file on it it will compile the epub. Attention: You have to modify line 6 (SET myzip=C:\Program Files\infozip\zip\zip.exe) according to the path on your computer.