Huo Yao (Fire-Drug)

Lots happening but, sadly, nothing I can blog about. I need to get some RC1 experiments done before I head off to San Diego for the ACS National Meeting and Research Pageant.  I really like this Mettler-Toledo RC1 and the sales and support staff. Pretty helpful folks in my experience. The Swiss make some fine equipment.

I spent the weekend reading about the very early history of gunpowder or Huo Yao (China, ca 850 AD). Turns out that the earliest clear description of a gunpowder-like composition was described in a document produced during the Tang Dynasty. A document titled “Classified Essentials of the Mysterious Tao of the True Origins of Things” contained a list of particularly dangerous elixirs.

Within this list of hazardous compositions, a warning was offered citing the dangers of mixing and heating together realgar, salt peter, sulfur, and honey.  The document tells of alchemists mixing this combination and heating it resulting in a deflagration leading to burnt beards, faces, and hands as well as the loss of the structure to fire. This mix was called “fire-drug”.

There are earlier references to compositions that produced a violent effect, but the compositions are not disclosed. The information in the 850 AD document clearly describes the components of classic gunpowder- a nitrate oxidizer, sulfur for low ignition temperature, and a carbohydrate carbon source- honey. Carbohydrates readily dehydrate to afford fairly concentrated carbon.

The realgar present in the mix is puzzling. It is not unreasonable to guess that the composition may have been intended for some medicinal application. Realgar is tetraarsenic tetrasulfide. This may have been an common apothecary ingredient of the age.

About gaussling

Gaussling is a senior scientist in the chemical business. He occasionally breaks glassware and has been known to generate new forms of hazmats. Gaussling also digs aerospace, geology, and community theatre. View all posts by gaussling

2 responses to “Huo Yao (Fire-Drug)

  • Joe Loughry

    Teaching a child to make black powder is a wonderful hands-on experience with science. It is not critical to get the proportions exactly right at first; mix equal amounts of yellow sulfur, white potassium nitrate, and black charcoal—when burnt, the colour of any residue will tell you which ingredient was present in excess. Good, safe, smoky, smelly fun when conducted out of doors on a flat stone, but confined by only a little pressure, and the character changes dramatically. A few layers of paper wrapping is enough.

    • gaussling

      Hi Joe,

      Nice to hear from the someone in the UK. I agree with your sentiment. I spent some time in middle school compounding homemade gunpowder from KNO3 and sulfur from the drug store and powdered charcoal brickettes. While I never had the nerve to confine the powder to make it go bang, I did experiment plenty with using it to melt holes in metal by deflagration. The actual experience of it was invaluable in gaining an understanding of the problems of ignition, safely experiencing the magnitude of the energy release, and just enjoying the simple act of watching nature’s energy unfold. Today I test reactive chemicals for a living. That early experience made a difference for me. It was fun too.

      Today in the US, if a kid tried that a SWAT team would be flown in by helicopter and black uniformed goons would drop from ropes and taser him first and ask questions later.

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