The mystery of Aqua Regia as a more effective gold dissolvent than the modern one. Perhaps because of the ancient strange work with salts.
These operations are nowadays hardly performed. To tell the truth the suppositions behind all that ancient chemistry were rather foolish: it will be enough to read the appalling theory about acids to understand the scientific imagination of the age.
So we cannot define these pages as chemistry, and sadly here Nicolas Lemery tries to give a rational too, but it remains the fact of his Aqua Regia being more effective in its main purpose: to dissolve metallic gold. As we will see, also his Fulminating Gold did act in a slightly different way than modern one.
We know that molecular purity was unwanted and not searched. Back at seventeenth century they have the myth of salts “penetrability” , which is rather alchemical though. In their mind a salt became penetrable when volatilized. We know where this concept could get to. Alcahest is not so far.
Nevertheless it is a fact that Aqua Regia is not an alchemical dissolvent. Our dissolvent is Alcahest, which reduces our metals to their seeds. In poor words: Alcahest, that’s to say Secret Fire reduces a metal in another Secret Fire. We look for nothing less in our work, a simple gold dissolution is quite useless for us. I said “ quite”, since in alchemical works imagination is the King.
You have already encountered all the countless operations to operate on salts to obtain Aqua Regia according to Lemery, that’s was in my articles Lemery & Aqua Regia First Step/ Sal Armoniac , Lemery & the Spirits of Salt Armoniac , Lemery & the Spirits of Common Salts with Wine and Lemery, Saltpeter & the Blood of Salamander . Here we will discover the goal, that’s to say where these works did intend to arrive: Aqua Regia and Fulminatig Gold.
I decided to maintain the chaotic connection system of Lemery, so I started translating from Fulminating Gold chapters and then Aqua Regia’s ( Fulminating Gold is a product of Aqua Regia). Nicolas Lemery “Cours de la Chymie” Paris, 1675. My translation from original french:
“Page 39: Fulminating Gold, called the Golden Saffron.
Take the quantity you like of gold filings, put it into a vial and pour in little by little three or four as much weigh as gold of Aqua Regia. Place the flask on warm sand till the gold will be all dissolved, which happens in an half hour time. Pour your solution in a glass vessel where you has previously put five or six as much volumes as gold solution of common water; then little by little pour on this mix some volatile Spirit of Salt Armoniac or oil of Tartar made by failure (1), you will cause the gold to precipitate at the bottom of the glass. Let it to rest for a long time in order not to lose anything; then pour by inclination the exceeding water, and wash your powder with warm water till the water will be strongly insipid, then make it dry on a paper at very slow heat, because the fire tends to run very easily and the powder to fly out with a great noise.
Fulminating gold induces sweating and push out the nasty moistures by transpiration. It may be of some utility against the Verole ( pox) at the dosage of two to six grains in a tablet, or in a opiate. it stops the vomit and the action of mercury.
One uses filings of gold in order to obtain an easier dissolution. One has to pour little by little the Aqua Regia to prevent matter from going out of the flask. This effervescence is consequent to the dramatic breaking of gold by Aqua Regia, since when Aqua Regia doesn’t find any body to act on anymore and having divided the gold in as particles as possible, the eruption will stop and even if the gold remains into the Aqua Regia this is not perceptible to us because we cannot see any change in comparison to what it was before, so much the water is clear and transparent.
One can use some oil of Tartar to make the gold to precipitate as well as some Spirit of Salt Armoniac, because both liquors do contain a salt Alkali, so when mixing it with acids they have to ferment: inside these fermentation the parts of Aqua Regia keeping in suspension the particles of gold are getting weaker and lacking the power to retain them, the particles precipitate by their own weigh.
May be someone will have an hard time to understand how the volatile Spirit of Salt Armoniac could make the Aqua Regia weaker, the same Aqua Regia which is composed by Salt Armoniac, but he has to consider that the strength of Aqua Regia is not dependent on the volatile salt armoniac, but on the marine salt which is in great quantity tied up with the Aqua Forte/Strong Water; since the marine salt or the rock salt may well substitute the salt Armoniac to make the Aqua Regia (2), as we will point when talking of this water composition. It remains to me to examine how the dissolvents abandon the bodies they have dissolved before to assault another. For example: why does the Aqua Regia leave the gold which is packed with to deliver the salt Alkali? This question is one of the most difficult to be answered in the whole physics. The following is some of the most sensible things one can say about.
I ( Lemery) suppose that when the Aqua Regia has operate on gold, and consequently has dissolved it, the points composing its force are attached to gold particles.”
The state of the art of the seventeenth century chemistry does provides this theory by which acids could dissolve and penetrate because they had sharp “ points” to enter and force the pores of other substances.
I can easily explain, with the same theory, the action of a powder composed by three parts of Nitre, two parts of Salt Tartar and one part of Sulphur. This powder being in a spoon, the quantity about a drachm weigh, it bursts like a cannon ball. The fixed salt of Tartar in this powder serves the same purpose of gold in the other, that’s to say that it retains the Spirits of Nitre and Sulphur joined together, in fact they cannot stand out with great violence but after having break their chains, and it this process to cause the noise.
The Fulminating Gold taken orally provokes sweating, because the heat from body gets it to volatilize and discharge from the pores. If it finds open pores, it produces just an inappreciable sweating. Someone thinks that the gold doesn’t contribute to sweating and that the Spirit of Nitre alone, being prevented by the body heat from leaving, does all the action. Nevertheless I believe that the Spirits of Nitre are more likely to take with them some parts of gold with which they are tied up. And by this explication one can understand how such a little quantity of Spirit can make to sweat; We have already mentioned that gold keeps mercury from violence, because it amalgamates with it, but Fulminating Gold does it better, since being volatile it does meet mercury sooner.
Page 311: Aqua Regia.
This water is called Regia or royal because it dissolves gold. It is also called “Stygia”, or Chrisulca.
The Vessels into which to make the royal water, or aqua regia, must be very wide, because during the dissolving phase the volatile Spirits tend to rarefy so impetuously to cause the vessels to break if they don’t have enough room. In the case of a large quantity of Aqua Regia to be prepared one has to promptly remove the vessel from fire as soon as the dissolution starts.”