Thanks to the internet, we can now track down a bit more information about Comte de Gabalis. The core text may date from 1670, but I think the passages Gene Kieffer quotes are likely from the commentary and notes added by Lotus Dudley in American editions from 1913 and 1922. Emma Curtis Hopkins (1849�1925) describes Lotus Dudley as an "occultist" (Gail M. Harley and Danny L. Jorgensen, Emma Curtis Hopkins: Forgotten Founder of New Thought, Syracuse University Press, 2002, p. 105). Comte de Gabalis and its Lotus Dudley commentary are online here:

http://books.google.com/books?id=J59bMimlOOsC

http://www.sacred-texts.com/eso/cdg/index.htm