雷公云∶凡使，勿用草中取者、并旧朱漆中者、勿用经别药制过者、勿用在尸过者、半
生半死者。其水银若在朱砂中产出者，其水银色微红，收得后用胡芦收之，免遗失。若先以
紫背天葵并夜交藤自然汁二味，同煮一伏时，其毒自退。
若修十两，用前二味汁各七镒和合，煮足为度。
雷公云∶凡使，勿用方解石。方解石虽白，不透明，其性燥。若石膏，出剡州茗山县义
情山，其色莹净如水精，性良善也。
凡使之，先于石臼中捣成粉，以夹物罗过，生甘草水飞过了，水尽令干，重研用之。
雷公云∶银气凡使，在药中用时，即浑安置于药中，借气生药力而已。
勿误入药中用，消人脂也。
雷公云∶铁气凡使，在药中用时，即浑安置于药中，借气生药力而已。
勿误入药中用，消人脂也。
雷公云∶金气凡使，在药中用时，即浑安置于药中，借气生药力而已。
勿误入药中用，消人脂也。
雷公云∶凡使，勿误用玄中石并中麻石。此石之二真相似磁石，只是吸铁不得。中麻石
心有赤，皮粗，是铁山石也。误服之，令人有恶疮，不可疗。夫欲验者，一斤磁石，四面只
吸铁一斤者，此名延年沙；四面只吸得铁八两者，号曰续未石；四面只吸得五两已来者，号
曰磁石。
若夫修事一斤，用五花皮一镒、地榆一镒、故绵十五两，三件并细锉，以捶于石上碎作
二、三十块，了，将磁石于瓷瓶子中，下草药，以东流水煮三日夜，然后漉出，拭干，以布
裹之，向大石上再捶令细了，却，入乳钵中研细如尘，以水沉飞过了，又研如粉用之。
Lei Gong said: When using Mercury (Shuiyin, 水银), do not use that collected from grass, nor that from old cinnabar lacquer containers. Do not use that processed by other medicines, nor that placed over corpses, or that which is half-raw and half-dead. If the mercury is produced within Cinnabar (Zhusha, 朱砂), its color will be slightly red; upon collection, store it in a gourd to prevent loss. If first boiled for one *fu* period (approximately 12 hours) with the natural juices of two herbs, *Zi Bei Tian Kui* (Oxalis corniculata var. purpurea) and *Ye Jiao Teng* (Polygoni Multiflori Caulis), its toxicity will naturally subside.
To process ten taels of mercury, mix seven yi units each of the aforementioned two juices, and boil until sufficient.
Lei Gong said: When using Magnetite (Cishi, 磁石), do not use Calcite (Fangjieshi, 方解石). Although Calcite is white, it is not transparent and has a dry nature. Gypsum (Shigao, 石膏), however, originates from Yiqing Mountain, Ming Shan County, Yan Zhou; its color is crystal clear like rock crystal, and its nature is benign and gentle.
When processing Magnetite, first pound it into powder in a stone mortar, sieve it through a fine mesh, then levigate it with water mixed with Raw Licorice Root (Sheng Gancao, 生甘草). Allow the water to evaporate completely, then grind again before use.
Lei Gong said: When using Silver Qi (Yinqi, 银气), place the whole piece among the medicinal ingredients to borrow its qi to enhance the medicinal power. Do not mistakenly ingest it directly, as it consumes human body fat.
Lei Gong said: When using Iron Qi (Tieqi, 铁气), place the whole piece among the medicinal ingredients to borrow its qi to enhance the medicinal power. Do not mistakenly ingest it directly, as it consumes human body fat.
Lei Gong said: When using Gold Qi (Jinqi, 金气), place the whole piece among the medicinal ingredients to borrow its qi to enhance the medicinal power. Do not mistakenly ingest it directly, as it consumes human body fat.
Lei Gong said: When using Magnetite, do not mistake Xuanzhong Stone (Xuanzhongshi, 玄中石) or Zhongma Stone (Zhongmashi, 中麻石) for it. These two stones resemble Magnetite but cannot attract iron. Zhongma Stone has a red center and rough skin; it is an iron mountain stone. Ingesting it mistakenly causes malignant sores that are incurable. To verify authenticity: if one jin of Magnetite attracts one jin of iron from all four sides, it is named "Longevity Sand" (Yannian Sha); if it attracts eight liang of iron, it is called "Xuwei Stone"; if it attracts five liang or less, it is simply called "Magnetite".
To process one jin of Magnetite, use one yi unit of Wuhua Pi (Bark of Five-flower Vine), one yi unit of Diyu (Sanguisorbae Radix), and fifteen liang of old silk floss. Finely chop these three items, crush them into twenty or thirty pieces by pounding on a stone. Place the Magnetite in a porcelain bottle, add the herbal materials, and decoct with flowing water from the east for three days and nights. Then strain, wipe dry, wrap in cloth, and pound again on a large stone until fine. Finally, grind in a mortar until dust-like, levigate with water, and grind into powder for use.