Purifying saltpetre with wood ash: Hasan al-Rammah
The Book of Horsemanship and Stratagems of War was written about 1280 by Hasan al-Rammah ('the lancer'), probably a Syrian. It contains many gunpowder formulae for incendiary arrows, fire lances and rockets, and Needham sees clear Chinese features in them: arsenic, lacquer and camphor in the compositions, 'Chinese arrows' (rockets), a firework called 'flower of China'.
For chemistry something else matters more: al-Rammah describes the purification of saltpetre. A solution of the crude salt is treated with wood ash, which precipitates the calcium and magnesium salts that draw moisture; the solution is decanted or filtered and left to crystallise. Partington calls this the first clear account of the process known to him. According to Needham the author of the Latin Book of Fires knew the same technique, but who took it from whom is not stated.
Gunpowder made from dirty saltpetre gets damp and burns sluggishly. Wood ash turns a chance salt into a reproducible reagent.
Why this date
approximate. The treatise is dated about 1280 by Needham; the author was probably a Syrian. The claim that this is the first description of purification follows Partington and Needham, both of whom qualify it as the first known to them.
Node sources
- Needham J., Ho Ping-Yü, Lu Gwei-Djen, Wang Ling. «Science and Civilisation in China», vol. 5, pt. 7: «Military Technology: The Gunpowder Epic», Cambridge University Press, 1986, p. 41 (1986), 41
written also about +1280 by Hasan al-Rammah (the lancer)
- Partington J. R. «A History of Greek Fire and Gunpowder», Cambridge: Heffer, 1960, p. 202 (1960), 202 Verified 4 Oct 2026
the first clear account of the process known to me is that of Hasan al-Rammah
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.