Thanks to WestMichBlue, who owns the original and scanned it for us, and to tcblue13 for providing the web host for the document, we can all read / download the original ASA softball rule book. The book dates from the 1930's (I'm not sure of the exact publication date).
Eventually, there will also be an accompanying article on the history of the rules of softball. The article, written by WestMichBlue, is not quite ready, so the link for that will just download a placeholder (empty) document.
Go to the
Softball Umpires web site, click on the Handouts page, and then click on Rule Articles.
Have fun.