The Chemical Basilica or Alchemical Royal Jewel

...and to replace the deficiency and absence from my manifoldly collected writings, after I had first examined and verified them through the fire, and through the entirely harmless substitution (according to the common alchemical custom, namely the addition and subtraction) often and much conferred with them and found that in this same conferring and conversation of ours, they exchanged an egg for a nut: in the long and tedious cracking of which I obtained nothing but a worm-eaten kernel, or in its place an unfit rind or husk. From this it follows that the greatest part of such people, without the Vulcan of nature—whom the poets hold to be the most truthful and best inventor and master of all arts and mysteries—which I say to them without prejudice, namely those who in our times have written about secret Spagyric preparations from the relation and claims of others, and have not experimented with them themselves, have created no greater benefit for the students and lovers of this art than that the same have wasted all effort and time after many vain expenses.

Learn to become wise from the harm of others, so that you do not regret your applied labor.

And that this is so in truth, all those will willingly acknowledge who, not satisfied with my example and the harm of others, subsequently examined such chemical mysteries themselves and finally became wise through their own loss. And just as among those things that are written in books, one finds them entirely void in the work itself, so it also stands between the practice and the mere theory, which all those experience who make themselves partakers of others' danger and want to be deceived by those who have been tricked and deceived by others. Therefore, no one in this study should believe more or further than experience leads them and than they can, so to speak, see and touch through the fire, which distinguishes the true from the false.

And since, according to the testimony of Aeschylus, that person alone is held to be wise and understanding who looks not at the many, but at the useful, I have much preferred to want to bring forth few and proven things, and have remembered the saying of Damascenus, where he says: One should attend to fewer medicines and choose among them those whose power and effects one has tested and experienced multiple times. In which small quantity, however, I can testify with truth that—excepting the general and most famous medicine of all, which the oldest philosophers had from the beginning of the world and left to their descendants with unspeakable fame—hardly any more select and powerful secrets lie hidden, since the good does not reside and consist in the great, but the great in the good. For whoever truly applies himself to philosophy and reflects with due earnestness and devotion on the innermost mysteries together with the natural causes in the preparations, and besides this does not let the labor of experience weary him, he will bring forth from this hidden womb of nature, through the diligence of his hands' work and the help of the Most High, much greater things than he was given in...