The Third Part of the Prosperity of Germany

is found in the book of Lazarus Ercker a famous 16th-century metallurgist, former imperial prefect of miners and highly experienced in his art, titled On the Testing of Metals original: "de Probatione metallorum". Since it is very difficult to present it more clearly than he has, I will refer the benevolent reader to him.

However, because the circumstances of some do not allow them to purchase a book of such enormous size just to learn the method of extracting and evaporating saltpeter, I have judged it advisable to append here, for the benefit of students of chemistry, what the aforementioned Lazarus Ercker has handed down concerning this matter. For I have never resolved to discard what has already been well taught by others; I only add what is my own. May others do the same, as authors of some novelty, so that the usefulness of the varied knowledge that God, the Best and Greatest, has bestowed upon us may overflow to our neighbor, for whose sake we are able to serve him.

But that we may acquire certain knowledge to distinguish the said stones, I deem it absolutely necessary to deal with them at greater length.

For although stones of this kind are found abundantly everywhere in the world, they are by no means recognized, because we cannot persuade ourselves that even the least bit of saltpeter is contained in them. For even if 100 pounds of such a stone contained 10 pounds of saltpeter, and we were to reduce it into the finest possible powder and extract the lye with water