The Greek alchemists apparently called the product of distillation “theion hudor”. Apparently “hudor” means water, and “theion” means either sulphurous or “divine”. The distillation process makes it clear that what is distilled is a liquid, not a solid, so the question arises precisely what is this sulphurous liquid. Sherwood Taylor suggests that the liquid is what you get from eggs, after distilling them. Apparently two of the extant recipes say to put eggs in the still, whilst others are unclear, so he suggests that eggs would fit the description. He goes on to describe three fractions that come off when eggs are distilled:
A clear distillate called “”rainwater”,
then a pale golden yellow liquid called “oil of radish”,
and then a third dark yellowish-green liquid called “castor oil”.
The names sound odd, but I do not know enough to be able to comment on them. I would have to go and learn ancient Greek, then read the original manuscripts. Anyway, Sherwood Taylor then says that you do get these three liquids when you distill eggs. The second and third fractions containing large amounts of sulphurous compounds. According to Zosimos, the second fraction can colour arsenic yellow. Now, not wanting to play with arsenic, although in solid form I suppose it wouldn’t be too dangerous, I decided that Sherwood Taylor’s suggestion that the distillate from eggs could confer a yellow colour upon silver was a good idea. I borrowed some silver from my dad, and bought eggs from the shop.
So I set up my fire as usual, then realized that I could not control the heat very well, by sitting the pot in the fire as you would when cooking, also it was too unstable for proper use. I ended up putting it on one side of the fire, as can be seen in the photograph below:
Here you can see the pot with 6 eggs in, with the still sat on top of it, sealed in place with clay all around. Unfortunately the still is too small for the pot, and therefore a good part of it is sitting inside the pot.
Clay is not the best luting for this experiment, I understand that the usual recipes call for dung and other organic matter, to bind the clay together and prevent it shrinking hugely when it dries. This will be explored properly later.
So, I chopped up lots of wood, finding that my axe work had improved a great deal. With the fire going properly, pot in place, linen wound round the still and dampened to try and reduce the temperature of the still, it all began to work. Small drops of clear liquid began to fall from the spout. Unfortunately a great deal was lost as vapour. The pottery still is not very effective, being too close to the source of heat, the fire, and also not having a long enough condensing line, so I certainly lost a great deal of sulphurous vapour. Which smelt quite bad. But at least there was no hydrogen sulphide.
This proceeded slowly, for 2 hours. I had to add wood at regular intervals, it was clear that the pot had to be kept at quite a high temperature to ensure the evaporation of liquid, as I would have expected given the higher temperatures necessary to evaporate sulphur based compounds, some of which would be large and complex. It may be that some of the white vapour escaping from the spout was steam, but I am not very sure about this. It seemed to move differently from steam.
All these experiments that I am doing are interesting and frustrating. Normally, in the chemistry lab at university, you knew or could find out what the desired result was. But on the other hand, you still had to pay attention to how well something was evaporating, to vacuum levels, temperatures at which something melted. Which is what I am doing here, with these experiments, but with this one, although I might be replicating a technique that is over 2,000 years old, I am really in the dark as to how things go, how they work, what it will look like. Any fool can drive, but driving so you don’t crash into people takes a lot more work. I am appreciating the work that had to go into learning this kind of craft, the uncertainty and the way you had to make personal judgments simply on the basis of the colour of a flame or liquid.
So, eventually I had gone through half a bag of wood and was not getting any further than the stage of dark yellow liquid. I took the small pieces of silver:
Nice and shiny, aren’t they?
And put them into a small vessel containing the yellow distillate, and boiled it, for nearly an hour, during which time the solution concentrated up, obviously losing the water that was in it. I left it cooling, and took the still apart, to find this:
Essentially scrambled eggs. It was clear that a huge amount of sulphurous compounds were still locked up in the mess, but I would have to raise the temperature to hundreds of degrees in order to break it down and distill off the heavy compounds which would give me the yellowy-green liquid that was mentioned in the book.
Eventually, after going for a long jog and tidying up a bit, I looked at the silver to see how it was:
The photograph does not show it very well, but you can clearly see that it is yellowed.
Perhaps it would have gone better had I used as much heavier dark yellow liquid as possible for the colouration, or maybe I could have pre-reacted the silver with something to make it more receptive of the sulphur compounds. Nevertheless, as far as the ancients were concerned, this was an important piece of work. There are many recipes for colouring metals in the early alchemical texts. It is only later, in the last 1,000 years that they are really obsessed with gold and the philosophers stone. 2,000 years ago it seems they were much closer to practical laboratory work, but lacking the knowledge we now have, they thought they were actually transmuting metals.