the Figures of these or other Saline Crystals (if I may so call Them) will be alwaies the same, whatever degree of Fire have been employ'd to force them up, or how hastily soever they have been made to convene in the spirits or liquors, in the lower part of which I have usually observ'd them after a while to shoot. And although, as I lately told You, I seldom found any Difference, as to Medical Vertues, in the fixt Salts of Divers Vegetables; and accordingly I have suspected that most of these volatile Salts, having so great a Resemblance in smell, in tast, and fugitiveness, differ but little, if at all, in their Medicinal properties: As indeed I have found them generally to agree in divers of them (as in their being somewhat Diaphoretick and very Deopilative; [Errata: Deopilative)] Yet I remember _Helmont_[18] somewhere informes us, that there is this Difference betwixt the saline spirit of Urine and that of Mans blood, that the former will not cure the Epilepsy, but the Latter will. Of the Efficacy also of the Salt of Common Amber against the same Disease in Children, (for in Grown Persons it is not a specifick) I may elsewhere have an Occasion to Entertain You. And when I consider that to the obtaining of these Volatile Salts (especially that of Urine) there is not requisite such a Destructive Violence of the Fire, as there is to get those Salts that must be made by Incineration, I am the more invited to conclude, that they may differ from one another, and consequently recede from an Elementary Simplicity. And, if I could here shew You what Mr. _Boyle_ has Observ'd, touching the Various Chymicall Distinctions of Salts; You would quickly discern, not only that Chymists do give themselves a strange Liberty to call Concretes Salts, that are according to their own Rules to be look'd upon as very Compounded Bodies; but that among those very Salts that seem Elementary, because produc'd upon the Anatomy of the Bodies that yield them, there is not only a visible Disparity, but, to speak in the common Language, a manifest Antipathy or Contrariety: As is evident in the Ebullition and hissing that is wont to ensue, when the Acid Spirit of Vitrioll, for Instance, is pour'd upon pot ashes, or Salt of Tartar. And I shall beg leave of this Gentleman, sayes _Carneades_, casting his Eyes on me, to let me observe to You out of some of his papers, particularly those wherein he treats of some Preparations of Urine, that not only one and the same body may have two Salts of a contrary Nature, as he exemplifies in the Spirit and _Alkali_ of Nitre; but that from the same body there may without addition be obtain'd three differing and Visible Salts. For He Relates, that he observ'd in Urine, not only a Volatile and Crystalline Salt, and a fixt Salt, but likewise a kind of _Sal Armoniack_, or such a Salt as would sublime in the form of a salt, and therefore was not fixt, and yet was far from being so fugitive as the