|The Latin alchemy text was called the Geberian
Summa and it has been shown to be a compilation of Jabir's writings.
The Summa clearly talks about a particulate or corpuscular theory
based upon Aristotle's concession, that there were 'minima naturalia',
or 'molecules' which limit the analysis of all substances.
The exhalation of the smaller particles of sulphur and mercury inside the earth led to a thickening and mixing together until a solid homogeneity resulted. Metals varied in weight (density or specific gravity) and form because of the differing degrees of packing of their constituent particles - implying that lighter metals had larger particles separated by larger spaces. Since the particles of the nobel metals such as gold were closely packed, the alchemist's task, according to the author of the Summa, was to reduce the constituent particles of lighter, baser metals in size and to pack them closer together. Hence the emphasis upon the submilmation of mercury and its fixation in the practical procedures discribed by Jibar. Such changes as density, malleability and colour of the metals were ascribed to mecurial agents that were refrred to as 'medicines', 'elixirs' or 'tinctures'.
Although these terms were also adopted in the west, it became more common to refer to th agent as the 'philosopher stone' (lapidens philosophorum). References to a stone as the key to tranmutation in fact go back to Greek alchemy abd have been found in a Cairo manuscript attributed to Agnathodaimon, as well as in the earliest known alchemical encyclopedia, the Cheirokmeta attributed to Zosimos (c 300 AD).
The Summa also contained an important defence of alchemy and of all forms of technology. Alchemy had always been to be to practial an art and it seemed to theologians that it gave people the divine power of creation. The Summa author, however, argued that people had the ability to improve on Nature because that was part of their anture and cited, amongst other things, farmers' explotation of grafting and alchemists' ability to replicate certain chemicals found naturally.