Georgii Agricolae medici Bermannus, sive de re metallica

This was indeed the principal reason why I betook myself to places that abound in metals. How much I have achieved there, I leave it to others to judge; but certainly, many witnesses can testify that diligence has not been lacking in me, especially Bartholomeus Bacchus and Laurentius Bermannus, men no less skilled in letters than in metallurgy the science of metals. I exhausted them—along with others—with frequent questioning before I came to know the metals.

However, since I am permitted at times to be free from the duty of healing and from more serious studies, it seemed good for many reasons to set forth the conversation that I received, which most learned men recently held about metals. First, so that I might offer to students a sort of taste of the future work which I have committed to writing about these same things. Next, so that I might incite the men of our time—so that I might not appear to have done nothing remarkable myself—to inquire into things more diligently. For unless these things themselves, being as they are endowed with their own powers, are known to us, we wear out words in conversation without any fruit. Finally, so that I might bring into the light, according to my abilities, those things which are found in metals in our Germany, which, so far as I know, were unknown to the ancients.