A colleague has written to me asking for some information. He says :
I am working with an Italian manuscript which is divided into six treatises concerning alchemy, and I’m trying to determine what the source for them is. The writer, a potter from Tuscany, is undoubtedly copying another text when he says that the first treatise
will be an introduction by means of theorics in the science of alchemy. . . explaining and declaring what many philosophers have said so as to avoid the errors of the ignorant. The second will be an introduction in the practice of alchemy . . . as much for the preparation of the Philosophers’ Stone as for other particulars which I extracted from a very ancient book . . . The third treatise will be the practice of the Philosophers’ Stone so that if this book happens to fall into the hands of unworthy persons it would not be able to be understood, but will be written in cipher that it can be easily understood (by the worthy) like my letters that you have received. The fourth treatise will be about the practice of the fixation and the multiplication of mercury . . . and this chapter similarly will be written in cipher . . . The fifth treatise will be a chapter about the aqua vitae and about a medicine with aqua vitae for preserving the health of the body and preserving memory . . . the sixth and last treatise will be a brief theorica and practica for obtaining the quinta essentia from any body, whether simple of composite. . . . and I have tried to write the present work in the common language . . . so that even though you do not read Latin you can still delight in this art and be able to understand its secrets . . .
Can you think of a text (probably published and written in Italian, and most likely available around Florence) that might contain these six treatises? The manuscript dates from the early 17th c., but I assume that that whatever text it is copying is much earlier. There is certainly a lot that derives from medieval ideas and the only name that appears in the manuscript anywhere is Avicenna.
Deconstructing the original post I would say Latin would be a likelier candidate than Italian for the language of the source text(s) and that the division into six treatises was the idea of the author and not something taken over from another text.
I would also suggest investigating Bernardo Buontalenti (pictured below) as the possible author of the Italian treatises.