狐丘，亦称狐刚子，是道家和佛家的双重修炼之巅。他的生卒年与籍贯不详，但据今人陈国符先生考证，他可能是晋代人，与葛洪同时代。狐刚子以其杰出的炼丹术闻名，被誉为“最大之外丹黄白师”。他留下了一系列著作，如《五金诀》、《出金矿图录》、《河车经》、《玄珠经》，这些作品反映了汉末我国炼丹术的高峰，并展示了他在化学发明方面的卓越成就。
尽管他的著作未能完整保存下来，但幸运地，在唐初的《黄帝九鼎神丹经诀》及唐代黄白术专著中保留了他的一些重要佚文。其中，《五金粉图诀》记载了他在水银制炼史上的重大发现。他提出改用密闭抽汞法，从而导致了我国炼制水银史上一个重大转折。此外，他还对铅化学有着深入的研究，尤其是在制取“铅丹”（Pb3O4）的过程中，为后世提供了宝贵的资料。
foxglove, also known as foxzhongzi, is a representative figure of both Daoist and Buddhist practices. His birth and death dates are unknown, but according to modern scholar Chen Guofu, he may have lived during the Jin Dynasty around the same time as Ge Hong. Foxglove was renowned for his exceptional alchemical skills and was hailed as "the greatest outside dan yellow-white master." He authored several works, including "Wujin jue," "Chugujing tuilu," "Hecarijing," and "Xuanzhu jing," which reflect the peak of alchemical knowledge in China during the Han Dynasty.
Although his writings have not been fully preserved, fortunately, some important fragments remain in early Tang Dynasty texts such as "Huangdi jiu ding shendanjing jue" and Tang-era treatises on yellow-white elixirs. In these works, we find hints of Foxglove's groundbreaking research on mercury extraction methods. He proposed a closed-tube distillation process that revolutionized water-mercury production in China.
Furthermore, Foxglove made significant contributions to lead chemistry through his work on creating "lead dan" (Pb3O4), which is one of the earliest recorded techniques in Chinese alchemy literature. Additionally, his expertise extended into metallurgy where he demonstrated an understanding of forming alloys between metals – a rare insight among ancient Chinese scholars at that time.
In summary, Foxglove represents a pinnacle of dualistic cultivation within Daoism and Buddhism. His life may have coincided with Ge Hong's era during the Jin Dynasty. As an accomplished alchemist named by contemporaries as “the greatest outside dan yellow-white master,” he left behind influential texts like Wujin Jue (Five Metal Secrets) that showcased advanced chemical discoveries even centuries later than their composition date suggests.
His most notable achievements include introducing closed-tube distillation for refining water-mercury from copper sulfide ore; discovering ways to refine gold dust using salt; improving methods for extracting silver from galena; developing techniques to purify zinc oxide from calamine; contributing innovative processes towards producing white arsenic via sulfuric acid treatment; investigating how tin can be extracted using antimony trisulfide compounds without losing its properties.
These findings demonstrate not only mastery over ancient Chinese metallurgy but also indicate extensive knowledge about mineral compositions that would continue influencing generations until today.
