THE THIRTEENTH CENTURY
Ideas on ‘impetus’ and the motion of the heavenly spheres.
Diversity of opinion on what keeps the heavenly orbs moving.
The recipe literature – craft manuals outlining recipes for manufacture of alchemical materials. For example, glass production had died out in the Latin West, but remained important in the Arab world.
ROGER BACON suggests that alchemical power can surpass nature (human artifice may exceed nature, i.e. technology), compared with Aristotle, who suggests that artifice may only mimic nature, or complete that which nature has failed to finish.
‘Suma Perfectionis’, Gaber – Latin Franciscan text (passed off as Arabic). Underpinned by the sulfur-mercury theory and by Aristotle’s ‘minima naturalia’ (smallest of natural things)– the idea of a minimum amount of matter to hold a form – hence a smallest particle of any given substance. This differs from atomism but the ideas were not developed by Aristotle.
Thus, in the middle ages came the belief that metals are created by the coalescence of minima of the metals.
Particles may be tightly or lightly packed (density). Matter may be contaminated.
Noble metals (gold) are tightly packed small particles, unaffected by fire or corrosion.
Lead turns to powder (oxidised) in fire as it is composed of larger, less tightly packed particles.
Sublimation is explained by smaller, lighter particles being driven upward by fire, and so on.
THE FOURTEENTH CENTURY
Texts become more secret, written in code and disguised. Latin texts are written in such a style so as to appear to be derived from ARABIC.
1317 – The Pope outlaws transmutation.
Moral questions: ‘is alchemical gold as valuable as real gold?’
‘Quintessences’: the refined essences of metals.
The discovery that lead cannot be turned to gold has important consequences. It is a strong indication that some substances are truly permanent and indestructible.