– the title referred to the physics of the earthly, as opposed to the celestial, sphere, and had nothing to do with weather forecasting. Less perfect metals, it was supposed, slowly grew to become more noble metals, like gold. Nature performed this cookery inside her womb over long periods of time – it was for this reason that, during the middle ages, mines were sometimes sealed so as to allow exhausted seams to recover, and for more metals to grow. If one interpreted the artisans’ aurifictions as aurifactions, then it appeared that they had successfully succeeded in repeating Nature’s process in the workshop in a short time. Perhaps further experimentation would bring to light other techniques for accelerating natural alchemical processes.
Although Aristotle had never meant by ‘prime matter’ a tangible stuff that could be separated from substances, this was certainly how later chemists came to think of it. Similarly the tactile qualities became substantialized (substantial forms) and frequently identified with the aerial or liquid products of distillation, or pneuma.
In gold-making, much use of analogy was made. Since there is a cycle of death and regrowth in Nature from the seed, its growth, decay and regeneration as seed once more, the alchemist can work by analogy. Lead is taken and ‘killed’ to remove its form and to produce the primary matter. The new substance is then grown on this compost. In the case of gold, its form is impressed by planting a seed of gold on the unformed matter. To grow this seed, warmth and moisture were requisite, and to perform the process, apparatus of various kinds – stills, furnaces, beakers and baths – was required, much of it already available from artisans or readily adapted from them.
A secret technical vocabulary was developed in order to maintain a closed shop and to conceal knowledge from the uninitiated, a language that through its long history became more and more picturesque and fanciful. In Michael Maier’s Atalanta fugiens (1618), we read that ‘The grey wolf devours the King, after which it is buried on a pyre, consuming the wolf and restoring the King to life.’ All becomes clear when it is realized that this refers to an extraction of gold from its alloys by skimming off lesser metal sulphides formed from a reaction with antimony sulphide and the roasting of the resultant gold – antimony alloy until only gold remains. As Lawrence Principe has noted, this incomprehension on our part is surely little different from today’s mystification when the preparative organic chemist issues the order, ‘dehydrohalogenate vicinal dihalides with amide ion to provide alkynes’. In other words, although alchemists undeniably practised deliberate obfuscation, much of our incomprehension stems from its being in a foreign language, much of whose vocabulary has been lost. On the other hand, we must recognize that obscurity also suited the rulers and nobility of Europe, who patronized alchemists in the hope of solving their monetary problems.
Greeks alchemy spread geographically with Christianity and so passed to the Arabs, who were also party to the ideas and practices of Indian and Chinese technologists and alchemists. The story that alchemical texts were burned and alchemists expelled from Egypt by the decree of the Emperor Diocletian in 292 AD appears to be legendary. Alchemy does not seem to have reached the Latin west until the eleventh century, when the first translations from the Arabic began to appear. In Arabic alchemy (the word itself is, of course, Arabic), we meet for the first time the notion of the philosopher’s stone and potable gold or the elixir of life. Both these ideas are found in Chinese alchemy. Two alchemists who were much revered later in the Latin west were Jābir and Rhazes.
Over two thousand writings covering the fields of alchemy, astrology, numerology, medicine and mysticism were attributed to Jābir ibn Hayyān, a shadowy eighth-century figure. In 1942, the German scholar Paul Kraus showed that the entire Arabic Jābirian corpus was the compilation of a Muslim tenth-century religious sect, the Ism’iliya, or Brethren of Purity. No doubt, like Hippocrates, there was a historical Jābir, but the writings that survive and which formed the basis for the Latin writings attributed to Geber were written only in the tenth century. Until very recently, no Arabic originals for the Latin Geber were known and many historians suspected that they were western forgeries, or rather original compilations that exploited the name of the famous Arabic alchemist. William Newman has shown, however, that the Geberian Summa Perfectionis, arguably the most influential of Latin works on alchemy, was definitely based upon manuscripts of Jābirian translations already in circulation, and that it was the work of one Paulus de Tarento, of whom nothing is yet known.
The Jābirian corpus as well as the Latin Summa were important for introducing the sulphur – mercury theory of metallic composition. According to this idea, based upon Aristotle’s explanation in Meteorologica, metals were generated inside the earth by the admixture of a fiery, smoky principle, sulphur, to a watery principle, mercury. This also seems to have been a conflation with Stoic alchemical ideas that metals were held together by a spirit (mercury) and a soul (sulphur). The theory was to lend itself beautifully to symbolic interpretation as a chemical wedding and to lead to vivid conjugal images in later alchemical texts and illustrations. As critics in the Latin west like Albertus Magnus were to point out later, this did not explain satisfactorily how the substantial forms of different metals and minerals were produced. What is most interesting, therefore, is that the Summa clearly speaks of a particulate or corpuscular theory based upon Aristotle’s concession, despite his objection to atomism, that there were minima naturalia, or ‘molecules’ as we would say, 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 noble metals such as gold were closely packed, the alchemists’ 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 sublimation of mercury and its fixation in the practical procedures described by Geber. As in the original Jābirian writings, such changes to the density, malleability and colour of metals were ascribed to mercurial agents that were referred to as ‘medicines’, ‘elixirs’ or ‘tinctures’. Although these terms were also adopted in the west, it became even more common to refer to the agent as the ‘philosopher’s stone’ (lapidens philosophorum). References to a stone as the key to transmutation in fact go back to Greek alchemy and have been found in a Cairo manuscript attributed to Agathodaimon, as well as in the earliest known alchemical encyclopedia, the Cheirokmeta attributed to Zosimos (c. 300 AD).
Apart from its influence on alchemical practice, the Summa also contained an important defence of alchemy and, with it, of all forms of technology. Alchemy had always been too practical an art to be included in the curriculum of the medieval university; moreover, it had seemed theologically suspect insofar as it offered sinful humankind 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 nature and cited, among other things, farmers’ exploitation of grafting and alchemists’ ability to replicate (synthesize) certain chemicals found naturally. As Newman has suggested4:
During this innovative period, alchemical writers and their allies produced a literary corpus which was among the earliest in Latin to actively promote the doctrine that art can equal or outdo the products of nature, and that man can even change the order of the natural world by altering the species of those products. This technological dream, however premature, was to have a lasting effect on the direction taken by Western culture.
Exoteric alchemy, committed as it was to laboratory manipulation, in this way bequeathed a commitment to empiricism in science and emphasized the centrality of experiment.
Al-Razi (850–c. 923), or Rhazes, was a Persian physician and alchemist
