Lawrence Principe - The Aspiring Adept - Incalescent Mercury

The main text of the Mercurialist school held that Philosophical Mercury was to be prepared by the purification of common mercury. This purgation must remove not only the external, visible impurities but also its "internal superfluities". The first are removed by straightforward means of purification - washing and grinding with salt and/or vinegar, distillation, combination with sulphur to form cinnabar (mercuric sulphide) followed by "revivification" with reducing agents, and so forth. The internal "impurities" are considered more intrinsic, being carried from the first formation of the mercury in the earth, not separable by ordinary means and yet not an essential part of the mercury; their removal required a "more Philosophical" manipulation. These impurities render common mercury useless for the Philosophical Work, because as DuClo writes, "it is necessary first to purge it and free it from excessive coldness and moistness" and incorporate other materials with it to increase its hotness. (DuClo aka Claveus - Apologia, De Triplici praeparatione auri et argenti). Collesson refers to the liberation of common mercury from "its phlegmatic nature... and from a black excrementious earth that was not part of its natural composition" (Jean Collesson - Idea perfecta philosophiae hermeticae). Van Suchten proposes cleansing common mercury from these debilitating impurities with an alloy of "martial regulus of antimony" (antimony metal reduced from the native sulphide ore by iron) and silver. The same agent is prescribed throughout the Philalethean corpus under disguised names, as Newman has shown (Newman, Gehennical Fire). Both Philalethes and van Suchten claim that besides cleansing common mercury, the antimonial alloy impregnates it with a "volatile Gold", otherwise called the "Mercury of Iron", which gives the prepared product its alchemically significant properties (Suchten - Secrets).

Once common mercury is rightly purified, it becomes more active and penetrating and is then called "animated" or "Philosophical Mercury". This animated Mercury can then be used for the "radical dissolution" of gold, and the mixture of Mercury and gold (after some further operations) digested into the Philosophers' Stone itself. The Mercury's action on gold is seen as twofold. First, its radical dissolution of gold liberates the "seeds of gold" hidden within the innermost recesses of the metal; second, like common water acting on plant seeds, this Mercury loosens their shells and nourishes them; indeed DuClo calls it "alimentum seminum metallorum", the aliment of metallic seeds. The germination, nourishment and cultivation of golden seeds allows for the multiplication of its virtue, as from one grain a plant grows to yield a hundreed grains or more, and thus the Philosophers' Stone is capable of transmuting base metals into gold. Common gold is dead, but the animated Mercury animates the gold in turn and makes it grow. This germination and growth process is visible, according to some authors; Collesson writes that the Mercury and its employment are not right "unless the common gold visibly vegetates and the peacock's tail appears. (Collesson - Idea perfecta)

[...] Boyle [...] begins by discussing the possibility that there exists a mercury "more subtle and penetrant than that which is common ... a more Philosophical Mercury" that bears a special affinity with gold and would grow hot ("incalesce") when mixed with it.

[...] Most important for the present study of Boyle's incalescent mercury is a fragmentary letter from Starkey to Boyle that has been dated to April/May 1651. This letter, discovered and published by Newman in 1987, contains Starkey's "key into antimony", a practical process lucidly described that results in the production of "a mercury that dissolves the mettals, gold especially". Newman has also discovered the missing segment of the letter (in a published German translation) where Starkey explicitly remarks that by his method "[common] mercury can be made into a mercurius Philosophorum".

[...] Starkey [...] never mentions that his mercury grows hot with gold. The identity of the mercuries of Starkey and Boyle can, however, be rendered certain. Starkey considers that the alloy of antimony and silver that he prescribes to be amalgamated with common mercury functions to "purge all superfluities from it", as witnessed by the black powder that the amalgam spews out when it is ground.

[...] When decoded, this receipt for incalescent mercury employs antimony [...] and copper [...] instead of antimony and silver. This apparently simple substitution is significant, for while Starkey prescribed the use of silver in his 1651 letter to Boyle and in most of the Philalethes' tracts, his 1654-55 Marrow of Alchemy repudiates the use of silver (specified under the Deckname "Diana's doves" throughout the Philalethean corpus) as "tedious labor" and substitutes instead "Venus" or copper.