Or, How to lose friends and make enemies
The downside of following authentic alchemical recipes is that, even although they are safe enough, some of them stink.
So it is with salt of urine.
The Kitab-al-Asrar of Ar Rhazi, the famous Arabic physician and alchemist has a recipe for making salt of urine. It says to take 10 litres of urine, leave it in the sun for 40 days until it becomes solid, or else put it in a fire until it becomes solid.
As you would expect there is an ammonia like smell to it. The recipe says you can let it become solid in hot ashes.
Possibly I botched this recipe a little, because I had a black substance when I had boiled all the moisture away:
By the way, the horrible bubbling black stuff from that video a couple of weeks ago is this experiment.
As is usual with early Arabic recipes, and alchemical recipes in general, there are alternative methods given. One is to distill it after ageing for a month, calcine the residue until it becomes white, and into the distillate add the hardened residue, some soda salt and egg shell calx and let it solidify like crystal over hot ashes.
Frankly, this one of those recipes which produces something of little to no chemical value at all, although if you’ve added the calx of egg shells and some sodium carbonate it’ll probably do some good if mixed with a molten metal. The alchemists at the time, especially the Arabic ones in the 9th century AD or so, were obsessed with classification and natural products in a way that the earlier more mystical Hellenistic alchemists weren’t. So anything which could be made or found was assigned to a class, never mind exactly whether or not it did anything, and when you treated urine like this, you got a salt, great, in the box marked salts it goes.
Or in other words, they were quite good at practical chemistry, and liked theory, but it was still not quite a science.
A further point is, why is the salt of urine so interesting?
I suspect one reason is the relation to medicine, Arabic scholars and physicians building upon their inheritance of the works of Galen and Hippocrates. Thus it seems possible that salt of urine was used because it was related to the humoral theory of the body, in which the four elements in food were digested and turned into the 4 humours within the body.
Unfortunately I can’t find anything about the medical theory of al-Rhazi; either it has not survived the centuries or it has not been translated into English. There are plenty of websites telling you how wonderful he was, but not much about his actual theories, which is annoying.
An earlier use of urine is the Physika et Mystika by pseudo- Democritus. It uses urine repeatedly as a solvent, to dissolve metals and their calxes and other substances of use. So it makes sense that the salt of urine would be of interest, perhaps as the active part of it, since the Arabic alchemists, artisans and physicians had inherited the texts of pseudo-democritus. The problem there though is that urine may well be a cover name for something else. The sheer straightforwardsness of Rhazi’s recipes helps persuade me that most are what they claim to be, substance wise, but of course other alchemists will have interpreted them according to their own ideas and used different substances instead.
Now, how does it taste? Salty, a little sharply, but nothing that I could pin down.
It’s pH in water is not dissimilar to pure tap water, and although I haven’t done a flame test on it I expect there to be a lot of sodium chloride and not much else. There should be some potassium as well, but really, in the firing, pretty much everything else will have been burnt off, all the nitrogen compounds etc. So as a chemically reactive agent it will be a non-starter, but as a symbolic entity it is of course very important indeed!