Alchemy had been a secret practice both in the West and the East. Internal alchemy is a practice to achieve Immortality, some form of which still survives today within some religious practice like Buddhism and Taoism. Soul immortality has always been a reality for religious or spiritual people, and the practice of internal alchemy can logically fit into the psyche of these people.
External alchemy is different. One key objective of external alchemy is to change base metal into precious metal. The financial objective is clear, whether or not the usage had been with "moral" reason, like one Robin-hood, is another issue. Some pundits say external alchemy is a precursor to modern chemistry. I beg to disagree. The practice of external alchemy is anything but scientific. I shall explain my contention.
The problem with a study of external alchemy is that such texts are obscured by symbols, anagrams and metaphors. It had to be like this, because a practice aiming to change base metal to precious metal, irrespective of any moral justification, will have an averse effect on the monetary system of a country. For one thing, there will be inflation, and consequently, there will be an "involuntary" transfer of income. In short such practice would most likely be considered criminal during those days. And certainly we couldn't see such practice manuals circulating clearly and freely!
One might ask if one wants to obtain silver or gold from nature, one can mine them! Very true. So the only reason has to be financial in nature. The alchemists wanted to create a substance to change base metal into precious metal, and profit from it!
Without any manual circulating around, how can one understand such hidden secret of the external alchemist?
Recently I came across some books written by a famous (many Taoists would say the most famous and knowledgeable) Taoist in Republic China, the late Mr. Chen YingNing (陳櫻寧). Mr. Chen was not affiliated with any Taoist lineage, his practice was learned through self-study, practice, experiment, and discussions with Taoist practitioners, lineage or otherwise. Mr. Chen practiced both internal and external alchemy. This was what Mr. chen said about external alchemy (he called it Alchemy of the Earth: 地元丹法, the more common term used by Taoists nowadays is WaiDan 外丹):
"I practiced Alchemy of the Earth and had proved that copper can be changed into silver through the practice...I spent about 10 years' time, did thousands of experiments, I had only this to say - copper can indeed be changed into silver, but with a financial loss.....In the 15th year of the Republic （Paul: i.e. 1925), I did it once in front of Mr. Huang at my home in Shanghai...After I have prepared the Elixir, I cut a piece of copper from a new electric wire and burned it with the Elixir, and obtained silver in the size of a bean. Although quite useless financially speaking, it does prove that the saying of changing copper into silver is not a false claim."
The question is if all previous alchemists had failed (financially speaking assuming successful technically, as per Mr. Chen's experiment), why had the practice been going on for decades both in the East and the West. The simple answer is, some had succeeded (again financially speaking, technical proficiency always assumed)! I shall solve the mystery below.
I had no reason to doubt the integrity of Mr. Chen, and, judging from comments from various sources and through reading his books, I had almost complete trust on the integrity of the man, and my analysis below shall be based on such assumption.
Putting this part of history aside, let us look at some other classical Taoist texts. Lu Dongbin (呂洞賓) is the recognized Great Grandmaster of all major Taoist lineages today, Lu being the forefather in internal alchemy (or Neidan 内丹). He learned both external and internal alchemy from his master Zhong LiQuan (鈡離權). There was this famous (metaphorical) episode between the master and the student: Zhong said he would teach Lu the practice of changing base metal into silver, so that Lu could use the money to help the poor. Lu asked how long could the silver remain as silver. Zhong said 25 years. Lu said in this case he wouldn't learn the practice because he didn't want the silver to be in unhappy hands 25 years later.
Nowadays ultimately how do people determine whether or not a piece of metal is silver (or gold)? We send it to the laboratory. That of course means a case that the piece has passed our initial visual inspection but we still have some doubt. Looking at the episode above, it seems that both master and student had no confidence that the silver thus created could remain able to pass relevant test(s) used during their time - indefinitely (or assuming they were highly intelligent, that I believe is a fair assumption, they were extrapolating progress in testing technology in future!!)
With the progress of science and in particular chemistry, the technology of metal testing had improved dramatically, so much so, the days of the external alchemists were numbered. And the practice became extinct. With this, I rest my case.
PS: In addition to transforming base metal into precious metal, some external alchemists also practiced swallowing such Elixir with disastrous results. I shall come to this issue in some future post. Stay tuned.