Where did the saltpeter used to make gunpowder in ancient times come from?

The invention of gunpowder is one of the great inventions in the cultural history of our country. Its origin is closely related to alchemy and materia medica. Black powder in ancient China is a homogeneous mixture of saltpeter, sulfur, charcoal, arsenic compounds, oil and other accessories, which is commonly used by China alchemists. Calling this mixture medicine also reveals its original relationship with traditional Chinese medicine.

The study of gunpowder history in China began with a pioneering work (1). He revealed the significance of the alchemist's original gunpowder formula in the Tang Dynasty, and studied the gunpowder and firearms in the Five Dynasties, the Song Dynasty and the Yuan Dynasty. In particular, he convincingly demonstrated that China's gunpowder first spread to Arab countries and then to Europe, which was the route of China's alchemy spreading to the west, and it was also similar to China's porcelain and papermaking spreading to the west. The great inventions in China's history have contributed to world culture.

Since the research in the early 1950s, the research on gunpowder has maintained this level of understanding for 30 years. Wang Kuike, Zhu Sheng, Zheng Tong and Yuan Shuyu [2] found in Ge Hong's Inner Chapter of Bao Puzi that the smelting process of arsenic can be made of saltpeter, turpentine, pig intestines and realgar: temperature is the key (that is, "fire" as China alchemists often say). Therefore, the origin of the original powder can be traced back to the fourth century AD. Fairy medicine should be the earliest recorded ingredient of raw powder. Wang's research is a new stage in the study of gunpowder history.

The introduction of saltpeter (potassium nitrate) plays a decisive role in the manufacture of gunpowder. According to Tang? In the 6th century BC, Li et al.' Taiping Yu Lan' said that "moving stones will lead to Longdao" and "stone sulfur will lead to Hanzhong". It can be seen that saltpeter and sulfur were used very early in China.

One view is that the place names "Longdao" and "Hanzhong" did not exist before the Qin Dynasty. What about Historical Records? Biography of Bian Que, Han? Liu Xiang's Biography of Immortals and Thirty-six Water Laws, presumably dating back to the Han Dynasty, both mentioned saltpeter. The use of saltpeter in the Han Dynasty was even more justified. Huainanzi? Astronomical training says: "Translate the Yellow from the Summer Solstice", and Shuowen records the production of "Huang Liu". Nitrate and sulfur in Shennong Herbal Classic are top grade and traditional Chinese medicine respectively.

In the Eastern Han Dynasty, the Book of Changes' Participating in Tongqi' said that "except Wudu, donate eight stones" and "drum-cast five-stone bronzes as an auxiliary pivot" ... all of which showed that five or eight stones, including saltpeter, had a fierce fire reaction because of their strong oxidation, and they were not tamed and mastered at that time. "Not to mention Wudu" is particularly noteworthy, indicating that some people had tried Wudu Realgar [4] and saltpetre, one of the eight stones, and it was probably unsuccessful, at least for the author of the magical device.

From Wei Boyang in the second century to Ge Hong in the fourth century, alchemy was in the ascendant, and the works of alchemy ranged from "Six Hundred Fires" (magical device) to "Thousand pieces" (Bao Puzi's inner chapter? Then "). During this period, there may be many alchemists conducting experiments of refining people with eight stones [5]. Arsenic oxide should be extracted from realgar with saltpeter. Ge Hong recorded a successful example of extracting realgar from three substances. Organic substances such as turpentine and pig intestines are introduced to reduce arsenic oxide to arsenic. But we still have to control the temperature. Above a certain temperature, it will catch fire and explode. In ancient times when there was no thermometer, there must have been a time when it exceeded, that is, there were successes and "failures" in refining arsenic. The latter case is the germination of raw powder. Later, the synthesis of gunpowder was also the result of actively using this experimental phenomenon. You can also learn from two aspects:

(1) The formula of early military gunpowder mainly consists of saltpeter, Sanhuang (realgar, orpiment and sulfur), turpentine (incense) and various oils and fats. For example, the gunpowder formula in Wu Jing Zong Yao in the Song Dynasty and the Fire Dragon Classic in the Ming Dynasty is the same.

(2) The introduction of China alchemy to the west is related to the introduction of China gunpowder to the west. Many specific operations and drugs used in alchemy in Arabia and Western Europe are the same as those used in alchemy in China. It was once attributed to Magnus, who first discovered arsenic, and was often attributed to the person who discovered gunpowder (another famous contributor was Roger? Bacon) Ge Hongzhi refined three kinds of realgar. Because of different temperatures, the properties of arsenic and gunpowder are different, and one side can use it for two purposes. Magnus has experimented and described arsenic and gunpowder, which should not be purely accidental. From Ge Hong to Magnus through the hands of many alchemists in China and Afghanistan (Rabe), there was originally a source relationship.