I don’t know what it is. The ash had a yellow tinge to it, and when I used it to try and make KOH it left me with this bright yellow solution. Funky colour, shame I don’t know what causes it.
It is likely a water soluble oxide of some sort; when I had an accidental fire last year some plastic and an old paint can with paint in it got burnt, and plastic often has metallic compounds in it to give colour and make it more light resistant. Metal compounds used include iron, barium, antimony, lead, nickel, chromium. Some of these aren’t very nice, so this is one substance I definitely won’t be tasting.
The analytical problem is that to carry out a simple flame test the potassium and sodium of the ash would probably mask any other colour present, since they are there in such quantities and give such bright flames.
One thing to try was to neutralise the KOH and CaOH present by the addition of vinegar, and see what that did to the colour. I took a sample and added acetic acid, it foamed and bubbled nicely, and the solution cleared slightly, but is still bright yellow. Now to work out how to separate the substances that are in solution.
An important substance in Graeco-Egyptian alchemy is Divine water, Theion Hudor, so called because the words for sulphur and divine are almost identical and it is made from sulphur and quicklime.
The ancient alchemists appear to have either liked a joke as much as anyone else, or been really serious about how similarities in names indicate similarities in properties and purposes. Burning sulphur was apparently used as a fumigant in temples and before rituals.
Anyway, several recipes survive. There is one in a text attributed to Zosimos, ‘On the Yellowing’ which says : “Divine water in a non-specific sense: this is the water made with two parts of lime and one part of sulphur, boiled in a pot, filtered and boiled once again.”Divine water is mentioned in the Physika et Mystika of pseudo-Democritus, the earliest set of alchemical recipes, although no recipe is given for it.
Then there is the Leyden Papyrus recipe for sulphur water, which says:
“The invention of sulfur water. A handful of lime and another of sulfur in fine powder; place them in a vessel containing strong vinegar or the urine of a small child. Heat it from below, until the supernatant liquid appears like blood. Decant this latter properly in order to separate it from the deposit, and use.”
The Leyden papyrus is a compendium of workshop recipes, used to make cheaper imitation gold and silver either for poorer customers or to defraud customers who thought they were getting pure gold or silver.
Now the chemists amongst you will notice that the acidity of vinegar will react with the alkalinity of lime. The divine water only works if you have an alkaline solution, but it is unlikely that the vinegar will have enough acetic acid in it to neutralise the lime so it should still work.
Anyway, I’ve managed to make it a couple of times before, but usually with water. It is best made on a strong fire or heater, since it takes quite a lot of heat and a good 10 or 20 minutes to get anywhere. I’ll try the urine method later, Lawrence Principe says that gets the best results.
So, here’s the 1:1 lime to sulphur mix in water at the start:
Here it is heating, nice and yellow:
Now we see the divine water forming, the red supernatant liquid:
This liquid is I believe what we want, and it matches the Leyden papyrus description as well as the later Arabic description of the process. Here’s a video of the liquid as the bigger, heavier sulphur and lime drops to the bottom of the flask:
What is miraculous is its colour when it is cool:
My previous attempts have resulted in a yellower more golden liquid. The wonder is obvious – we have a liquid which goes from yellow/ gold to red when warmed up, contains sulphur as is obvious from the smell, and tints metals.
Yes, colours metals. Which is the subject of another post.
Oh yes, you’ll be wanting to know what the red stuff is? It’s calcium polysulphide, Ca –S-S-S-S-S-S-S-S-S-S-S etc. Normally sulphur at room temperature and pressure forms rings of eight S atoms, but in caustic liquid near boiling temps the rings open up and join with others to form long chains of sulphur.