Sawston Village History Society

November talk to the Sawston Village History Society was given by Dr David Bard on the somewhat esoteric subject of " Alchemy" from which the science of chemistry later evolved. Unlike his modern counterparts however, the alchemist, rather than seeking to further his knowledge by the discovery of new methods, sought to rediscover and reinterpret the works of earlier practitioners, so wished his work to appear ancient!

The first group of relatively well documented alchemists were those from Grecian Alexandria around 300BC. Their main interest was in the transmutation of "base" metals, such as lead, copper and antimony to gold or silver. At that time it was believed that if a certain mixture of various metals such as copper and lead, with some other ingredients, including sulphur, mercury and ores, after heating, resulted in something which looked, felt and had the same density of gold,( this was after Archimedes had his famous bath), then it WAS gold! Sadly for alchemists, however all these necessary properties in one mixture were never achieved. It appears that some alchemists extended this idea into trying to make artificial humans or humancolis using recipes and methods which David described as gross. At this time the most well known of these Alexandrian alchemists were Zosimus and one of the few female alchemists, Mary the Jewess. These and their contemporaries developed high temperature furnaces in an attempt to prepare yellow metallic substances by removing the yellowness from one substance and transferring it to another, usually a metal, and also developed stills. These designs are still recognisable in the modern chemistry lab.

After the decline of Alexandrian alchemy, presumably not unrelated to the increasing influence of the more pragmatic and engineering minded Romans, the next resurgence in alchemy was in the Islamic world of around 900AD, the most well known one being Al Geber or Jebir who wrote some important treatises. Like the Greeks, he classified substances into three main categories:

1) Spirits: volatile substances such as camphor, sal ammoniac, arsenic and sulphur.
2) Metallic bodies: metals
3) Non - metallic bodies: Apparently everything not in the first two.

Importantly mercury was categorised as a metal rather than a non - metal. Jabir was the first alchemist to introduce the concept of the 4 elements of fire, water, air and earth, and all metals were made up of combinations of these. Geber was one of the first to describe the production of nitric acid, and also acetic acid by the distillation of wine vinegar. In the 14th century Europe some important alchemical writings indicated the requirement of a 5th element or "argent vivre", called a "quintessence". Some of these alchemical processes were linked to horology and hence some of most well known metals were associated with the planets, for example: Mercury - mercury, Venus- copper, Mars- iron, Jupiter - lead, and Saturn - tin. Some of these texts include "recipes" which are clearly interpretable as definite chemical processes, and led to the emergence of modern chemistry in the 18th century. The 17th century alchemists were believers in the Hermetic philosophy (from the Greek god Hermes). This related God with a world which could not be visualized , sensed (or indeed understood) by mere mortals.

Other people associated with this somewhat mysterious world were, John Dee, Paracelsus, Copernicus, Agricola, then into the dawn of modern chemistry with Robert Boyle, still very much into alchemy although his gas law now forms a fundamental part of modern physical chemistry. Surprisingly, Isaac Newton also wrote many texts on alchemical topics which are now kept at Kings College. His rooms where he carried out much of his alchemical experiments can still be seen. Unlike many alchemists, Newton survived into his 80s, probably because he stopped his practical alchemy while he was relatively young. The processes involving the emission of highly toxic materials such as mercury, arsenic and antimony was not conducive to longevity!