_I could not place the several Treatises in that order which the Author published them, without breaking the order of the several parts, as of the =Miraculum Mundi=, =Spagyrical Pharmacopœa=, and =Prosperity of Germany=; for being many years in publishing, they were done promiscuously, but how they succeeded one another so far as the =Nature of Salts=, the Reader may satisfie himself in the Preface to that Treatise. And as his Writings were published by piecemeal, so are the principal Secrets he teacheth, scattered up and down in divers parts of them, in one place he treateth of a thing obscurely, or but in part; in another place of the same thing openly in that part which he had veiled in the other. Sometimes he declares a Process very openly, omitting only some small Circumstances, or Manual Operation, which would seem to many either impertinent, or not necessary to be done, when notwithstanding, the business will not succeed without it. An instance of this may be given in his =Sal Mirabilis=, whose preparation he teacheth obscurely in the =Nature of Salts=, but more openly in the Second Part of =Miraculum Mundi=. In the =Nature of Salts=, and in the Sixth Part of the =Pharmacopœia Spagyrica=, he teacheth how to Dissolve Gold therewith, and thence to make a kind of =Aurum Potabile=, but wholly omits the adding of a certain Vegetable Sulphur, without which, the work will not answer the Description; this Defect he supplys in the =Second Century=, after a twofold manner, the one not obvious to every Man’s Apprehension, I mean the intent of the Author, =viz.= in those Processes where he shews the making of a Vegetable Sulphur; but the other sheweth the necessary Manual Operation in plain and open words. And this he hath done with all his Secrets on set purpose, that they should be found out by none but the Industrious._ _And this hath given occasion to many, who have not taken pains to read him with diligence, or not being experienced in Operating, to reproach him for an obscure, yea, even for a false Writer, because they have made two or three Superficial, or Unskilful Trials of his Processes, which have not succeeded according to their Expectations; when indeed, the fault was in themselves, either in not perceiving the Author’s intention, or their own want of skill in rightly managing the Operation: And I know some Persons that sometime since said =Glauber= had been too dark in his Writings, who now think he hath wrote too plain._