“One can also makes Aqua Regia with equal parts of saltpetre and Rock Salt, mixing these salts with as much threefold Bole in powder and performing a distillation in the same way we have already mentioned, to extract the Spirit of Nitre.
It is very difficult to understand how the Aqua Regia dissolves gold, which is a very firm and stable metal, and cannot dissolve silver which is less hard. Some chemist eager to solve this difficulty have said that metallic gold does contain more Sulphur than Mercurius, demands for a sulphureus dissolvent as Aqua Regia seems to be, since it is composed by the sulphureus volatile salts constituting salt Armoniac: but this explication denies itself because if the gold contained more Sulphur than the Silver, consequently it would be less heavy, since Sulphur is one of the lighter chemical principles.”
On chemical principles see Glaser 2, Active three Principles. Here Lemery is loosing himself in a chemical superstition of his age: the belief that an oily generic substance together with a milky generic one did composed all metals. The oily was called Sulphur and the milky one Mercurius. Of course, not only this theory is false, but the alchemical Sulphur and Mercurius are the same substance just in different stages (3).
“If besides we examine the composition of the gold dissolvent it will not difficult to contradict this opinion, since we can easily see that as soon as the Spirit of Nitre begins to penetrate the Salt Armoniac, the acid salt ties up with it and leaves the volatile salts, which finding itself without a body keeping it fixed, rises dramatically; but as these salts, which are alkalis, meet in their way some acid of Spirit of Nitre which penetrate them, the usual great effervescence of a salt alkali running into an acid is being made. This being passed, our Aqua Regia does remain the vessel; this is just an acid marine salt dissolved in the Spirit of Nitre, the volatiles salts being exalted or being destroyed by the acid. An evidence of this thinking is that we can make the Aqua Regia either with marine salt, which has not volatiles inside, or with salt armoniac as we have said.
But these considerations cannot make this phenomenon clear, I think (Lemery), in order to give a rational, that if the Aqua Regia cannot dissolve the silver, because in the Spirits of Nitre the addition of salt causes the points to be too much large to affect the silver’s pores. And consequently they are not allowed to enter, while they are allowed to penetrate the gold, which pores are larger. If, on the contrary, the Spirits of Nitre can dissolve the silver is because its points are as subtle to enter the little pores oft his metal. This little pores can enter the larger pores of gold, but they are too much little and folded to have an action on this body. So one needs knifes more sharp and cutting, which still being of a suitable size have also the power to cut the gold’s pores.
I know that you may object that the gold, being heavier than silver, must have smaller dimension pores, as the weigh of a body must only consist on a great nearness of the parts, but it is very easy to have a closer look into that with a good microscope. In this case one can see that gold’s pores are larger than silvers’s, but they are considerably less in number, and this can explain why gold are heavier than silver, since they are larger but far from each other, and in fact we can see a very compact mass which makes all the weigh. The silver’s pores are very close each other and in a large quantity, so around them there is less mass and consequently silver has a less weigh. I will use a familiar example to make myself clear.
If I take two bowls of the same size and volume one packed with balls of caliber and the other with filings of lead, the first will be by far heavier in spite the major empty space among the balls. For the same reason gold is more malleable than siver and can be cut more easily, since if the pores of a body are larger it is more easy for a knife to enter. And for the same reason a hammer can dilate the gold more easily.”
You can find a modern comprehensive essay to perform ancient methods to get Aqua Regia at Aqua Regia & Fulminating Gold by Phantom Play.
- See Lemery and the Fixed Salt of Tartar Called Oil by Failure ;
- For the reasons Lemery prefers Rock Salt to marine salt see Lemery and the Spirits of Common Salt with Wine ;
- See also Stuart Chevalier, a Virgin’s Marriages ;