We are starting to accumulate these!
Hentzner, Paul
Naunton, Sir Robert
Pepys, Samuel
Raleigh, Sir Walter
The Discovery of Guiana
http://hops.whorton.upenn.edu/~loren/Links/maloney/alchemy/quinhome.html
The full text and translation of "The Book of Quintessence" a mid-15th century alchemical text. Bryan has a warning/disclaimer against "dabbling around in chemistry" without training in safe handling practices and hazardous substances, in which this text abounds! As he points out that, like many would-be alchemists, you, too, could wind up "hurt, crazy, or dead" from actually performing any of the operations described -- not because they're demonic, but because mercury et al rots the brain. T3
http://promo.net/pg/
"Fine Literature Digitally Republished. Since 1971 putting classic books into electronic form." You can download many texts of the time for free, each as a single big text file. Burn your own reference CD-R.
http://www.fordham.edu/halsall/sbook.html
Halsall is collecting texts in translation, and also providing links to other sites like Berkeley, so as not to duplicate effort. This huge initial page links internally and externally to a list of period works, from the late Byzantine-early Christian age to the early Renaissance. Wonderful source, attractive without glitz, many matrices of approach (eg, by a topic like women's roles or by a period). This gets bigger and better all the time.