Petral stone

A few lines above the anagram, the author sets down the composition of black powder in another manner. Take then of the bones of Adam (charcoal) and of the Calx (sulfur), the same weight of each and there are six of the Petral Stone (saltpeter) and five of the Stone of Union. The Stone of Union is either sulfur or charcoal, probably sulfur, but it doesn t matter for the context has made it evident that only three components enter into the composition. Of these, six parts of saltpeter are to be taken, five each of the other two. The little problem in algebra supplies a means of checking the solution cf the anagram, and it is evident that the passage ought to be read as follows ... 

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See also in sourсe #XX -- [ ]

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