The second procedure: Trituration (mardana)
The terms used for the alchemical procedures sometimes evoke the language of ayurvedic therapy. Svedana, the "steaming" of the first alchemical procedure, has a correlate in ayurvedic treatment. There, svedana is the application of heat to the patient's body, which results in the patient sweating (the translation for svedana here). This is sometimes done by using a closed steam chamber for the patient.
Sweating therapy is often preceded by the internal and external application of oil. The general idea is to let the body absorb oil to loosen unwanted materials in the channels of the body. To facilitate the absorption of oil through the skin, the oil is rubbed in vigorously, and this massage is called 'mardana'.
In the alchemical tradition, mardana is the second of eight procedures that cleanse mercury. Mercury has already been made to sweat in the steaming process, as it were. Now it is rubbed with several substances. However, none of the ingredients are oily, so perhaps the correspondence with the ayurvedic mardana does not go very deep here.
The Heart of Mercury describes the procedure as follows:
"Trituration with sour gruel is carried out for three days with molasses, burnt wool, and salt, together with soot, brickdust, and mustard, each in the amount of a sixteenth part to the mercury."
These ingredients are quite easy to procure.
I was a little surprised at how burnt wool is produced. Rather than just setting it on fire by putting a match to wool (which apparently doesn't work that well, as wool is not that flammable), the wool is calcined in a closed container.
This is how that is done:
Molasses could have been jaggery instead. For the brick dust... you grind a brick. For the soot, you grind some charcoal. Or starting from first principles, you burn some wood, then grind the resulting coals.
As for the mustard, we went with mustard seeds this time around. However, Andrew departed a bit from the description of the text by using a mustard seed decoction in addition to the mustard seeds. This was instead of sour gruel (kāñjika). Sour gruel is fermented rice water. You boil rice (or sometimes another grain) and let it sit for several days in the water you boiled it in until it ferments. The same sour gruel is used for the steaming in the first procedure. I am not entirely sure why Andrew substituted sour gruel for mustard seed decoction. I must admit it escaped my notice entirely when he showed me his film. In any case, here is his version of the procedure:
Rubbing, or triturating liquid mercury with this mixture changes its appearance quite dramatically: the mercury becomes a thick paste. This takes a while. The text is not kidding when it says you do this for three days. It takes a whole lot of elbow grease to arrive at this paste-like consistency. Andrew said he was starting to look like Popeye after rubbing the mixture with mercury for all those hours. You can see how mercury becomes like a paste in the film at 8:25-8:30. However, when you recover the mercury from the other materials, which is done through washing the mixture with water and with vinegar, the mercury becomes less and less paste-like and is restored to its more familiar mobility and shine. Note that the washing is not mentioned in the Sanskrit text. If one simply follows through the description, one would use the entire mixture for the next procedure: Thickening (mūrchā).
Another thing: this procedure is sometimes done over a mild fire, so the ingredients are slowly and evenly heated throughout. This is how Dr Kale, one of the experts Andrew consulted with, did this procedure (see Dr Kale's picture below). In that case, the mortar one works with needs to be stone or metal. Mercury's boiling point is 356.73 °C (674°F), but it can already evaporate at room temperature. Higher temperatures lead to higher evaporation rates. Since mercury vapour is highly toxic, proper ventilation and safety equipment is very important at this step.
As always: don't do this at home, folks!