Larry Sanger responded: "To answer the question: no, 1913 is too old."
I don't understand this response. We have a handful of articles from the public domain version of Britannica, which is quite old, and these articles are too old, because much of the information is hopelessly outdated. But a dictionary is different. A 1913 dictionary surely has a perfectly good definition of 'shotgun' for example. Since I didn't know there was a 1913 public domain dictionary, I had to dig up a very legalistic definition from the US legal code.
I think that using the public domain 1913 Webster's Unabridged as a basic reference for definitions of words can be very helpful.
Of course, it is important for us to remember that Wikipedia is an encyclopedia, not a dictionary, so the random copying of entries from that work can be discouraged. But using those entries as a jumping off point seems like a great idea.
I mean, shotgun is a great example. I "just knew" what a shotgun was, but never tried to put it into words. I found it very difficult to do so! A dictionary definition, especially a public domain one that I could just freely copy without questions of fair use, etc., would have been great.
I have no objection whatsoever to putting a link to a 1913 public domain dictionary on the PublicDomainResources page. My reservations are about what people will most likely do with it. --LMS
I've used the 1913 dictionary and found that most of the definitions are the same as the modern day dictionary. It serves as a good fundamental public domain quick reference for topics.
Project Guttenburg has a 1921 encyclopedia volume A online also... The data is dated but most of the classical topics in it are worth using. For example, an entry for Angola would be dated but a biography of John Adams would not necessarily be dated.
Encyclopedia is at: http://promo.net/cgi-promo/pg/t9.cgi?entry=200&full=yes&ftpsite=ftp://ibiblio.org/pub/docs/books/gutenberg/