An appendix to a course of chymistry being additional remarks to the former operations : together with the process of the volatile sale of tartar and some other useful preparations / writ in French by Monsieur Nicholas Lemery ; translated by Walter Harris ...

Add to pag. 190. the end of the Remarks upon Aqua Regalis.

It is Objected, that if there is any heavy matter as it were intercepted between the Pores of Gold, it must needs Precipitate of its self, after the action of Aqua Regalis upon this metal, which is a thing that does not happen.

I Answer that if the parts of Gold are heavy, the Dissolvent is a gross body, and very well pro∣portioned to hold up those heavy parts, and hin∣der them from Precipitating.

Others have opposed this Explication, and have writ, that if Aqua Regalis dissolves Gold, and can't dissolve Sylver, the reason of it is, that the gross points of spirit of Niter, or Aqua fortis are subtilized by the mixture of sal Armo∣niack, and are rendred fit to enter into the small pores of Gold, whereas the delicate Fabrick of these same points does not leave the necessary force nor motion to divide the parts of Sylver, whose pores are a great deal bigger.

But this way of arguing does not agree with Experience; for what likelihood is there that the points of spirit of Niter are so subtilized by the penetration and division of the parts of sal Armoniack? or where shall we find any Exam∣ple, that after a considerable Effervescency of

two salts met together in conflict, the Acidity grows sharper than it was before? this is a thing that can never be proved. On the contrary, every body knows well enough that no Efferves∣cency happens but the acid is partly blunted or broken thereby. Moreover the Argument sup∣poses that spirit of Niter does break its subtilest points in violently contending with the sal Ar∣moniack, whereas in sal armoniack there are Al∣kali salts whose property it is to destroy acids. I could further add here, that the conjunction of salt with spirit of Niter should of necessity ren∣der its points more gross than they were, and that the Crystals which are drawn by the use of aqua Regalis have their shape not so sharp as those that are drawn by aqua Fortis. But that which I have said is so probable in its self, and so easie to be convinced of, if one takes never so little pains to consider it, that I should but amuse the Reader to little purpose, if I should offer to give any more proofs of it.

Neither do I find it convenient to make a long discourse in Explicating how Sylver, which has lesser Pores, is more susceptible of the im∣pressions of Air and Fire, than Gold which has larger, seeing I have already supposed that the matter intercepted between the Pores of Gold is more compact, and consequently more hard to separate than that of Sylver.