The Golden Elixir

① True Yin (Mercury) and True Yang (Lead). The most common designations of the ingredients of the Elixir.

The people of our times should comprehend True Lead and Mercury: they are not the common sand and quicksilver. 時人要識真鉛汞、不是凡砂及水銀。

Lead is the one particle of True Yang (⚊) within Kan ☵; we call it Dragon. Mercury is the one particle of True Yin (⚋) within Li ☲; we call it Tiger. 鉛者，坎中一點真陽，謂之龍也。汞者，離中一點真陰，謂之虎也。

When Lead is clear and Mercury is pure, they will coalesce and form the Golden Embryo, which is equal to Emptiness and is indestructible for countless eons. 鉛清汞潔，結成空無金胎，歷劫不壞。

② Nature and Existence (xingming). (In Li Daochun’s exposition of Neidan, this definition only applies to the Supreme One Vehicle.)

In the Supreme One Vehicle, Lead and Mercury are Nature and Existence. 〔最上一乘，以〕性命為鉛汞。