Treatise on the Lead-Mercury Elixir 大丹铅汞论

Compiled by Jin Zhupo in the Tang Dynasty, this book consists of one volume and is included in the Methods category of the The Dongshen Section in The Daozang.

This work elaborates on the principles and methods of refining the Great Elixir using lead and mercury. It first points out: "The art of the Great Elixir originates from lead and mercury." Lead, as the leader of the five metals, contains mercury within it—symbolizing the Li trigram (Yang with Yin), like fire generated from wood, and is known as the Azure Dragon (Qinglong). Those who refine elixirs extract mercury from lead, enabling the mutual interaction of Kan and Li trigrams (Yin and Yang); when lead and mercury combine, the elixir can be formed.

The elixir-refining process is as follows: First, melt black lead and mountain silver to obtain lead yellow flower, which is called the White Tiger (Baihu) or "gold in water"; then refine mercury from cinnabar, named Jade Fluid (Yuye), which is the Azure Dragon (Qinglong) or "mercury in cinnabar". Next, mix the obtained true lead and true mercury in equal parts, place them in a cauldron, seal it tightly, and nurture with fire: "Lead descends when combined with mercury, and mercury submits when merged with lead—thus forming the Dragon-Tiger Great Elixir."

The book also discusses the method of transforming the Four Spirits (Sishen) into the Great Elixir. Roughly, the method involves wrapping mother cinnabar, spirit cinnabar, and cinnabar with each other, nurturing them with fire to blend the three cinnabars into a "Four Symbols Container (Sixiang Kui)"; then nurturing mercuric chloride in the container to form White Snow (Baixue), which transforms into yellow powder; further nurturing the yellow powder with lead-silver to produce lead-yellow xin (a refined intermediate), and combining this xin with cinnabar to "nurture to stability"; finally, nurturing mercury with lead-silver to form the Great Elixir.

The book states that this elixir "gradually shines, and from brightness, gold and silver are generated, and all treasures emerge. The techniques of solidifying mercury into gold and transmuting metals all originate from this elixir."