Alchemy

One of the aims of the alchemists was todiscover and use the magical Philosopher’sStone, which was supposed to change

worthless metals into gold. The alchemists thoughtthat this was possible because they believed that everysubstance was a combination of the four elements:earth, air, fire and water.

GoldGold was a key material in alchemy. Its coloursuggested the Sun, and its complete resistance tocorrosion marked it out as something special. Goldwas the only metal that could not be dissolved awayby ordinary acids. It even resisted concentrated nitricacid. Thus, acids could be used to distinguish betweenreal gold and a mere yellow alloy such as brass.

Gold also had symbolic significance as the metal ofkings, princes and emperors because it representedtheir nobility — their supposed immunity from thebaser concerns of the common people. Alchemiststhought that turning the base metal lead into thenoble metal gold was simply a matter of dissolvingaway the unwanted qualities and nourishing the ‘seed’of gold. Like all metals, gold was thought to besomehow born from Mother Earth. This process wasbelieved to be like the normal plant cycle of life anddeath followed by regeneration.

The ideas behind alchemyThe complex ideas underlying alchemy were a mixtureof detailed practical knowledge and ancient religiousand mystical beliefs, as well as the thoughts of Greekphilosophers.

The planets played an important part in this, andmany substances, especially metals, had astrologicallinks (see Table 1). Unsurprisingly, the Sun repre-sented gold, and the Moon silver. According toalchemical theory these two metals also representedcomplementary opposite ‘masculine’ and ‘feminine’characteristics, like the ‘Yang’ and ‘Yin’ of Taoism,which are linked to day and night, Sun and Moon andso on.

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GCSE key wordsDistillation

Scientific methodAcids

Corrosion

Alchemy is the study of eternal life, salvation,and the answers to the ultimate questionsabout life, the universe and everything. Itf lourished for more than 1500 years until, inthe late 1600s, the beginnings of modern,scientific chemistry edged it aside. But whatwas alchemy and who were the alchemists?

John Tucker

Box 1 Henning BrandtHenning Brandt was a German alchemist of themid-seventeenth century. Brandt discoveredphosphorus accidentally, about 100 years beforeJoseph Wright’s famous picture of him waspainted. It seems that he had an idea that gold andthe yellow colour of urine were connected in somemysterious way.

While heating the solid residues he had got fromevaporating several buckets of stale urine withpowdered charcoal he found that phosphorus,glowing and burning, distilled from the flask. Hebelieved that he was on the threshold of discoveringthe Philosopher’s Stone. He wasn’t, of course, andeventually he sold the recipe, which he had keptsecret for some years, to cover his debts.

We still use theexpression ‘the acidtest’ to mean anespecially critical test ofgenuineness.

‘The Alchymist, In Search of thePhilosopher’s Stone, Discovers Phosphorus,and prays for the successful Conclusion ofhis operation, as was the custom of theAncient Chymical Astrologers’.This famouspainting by Joseph Wright of Derby, from1771, almost certainly portrays HenningBrandt, a German alchemist of the mid-seventeenth century

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Practical chemistsAlchemists were the chemists of their time. They usedthe same methods of extraction and purification asyou will have encountered in the laboratory: filtration,distillation and crystallisation, for example. Like you,they heated and mixed substances to see what wouldhappen. They used acids and alkalis, dissolved thingsin water, and ground solids up into powders to makethem react more efficiently. Their pieces of apparatusmay look rather odd, but the alembic (see Figure 1),for example, was basically for distillation.

Alchemists did thousands of experiments and thenrecorded their observations. However, the languagethey used was often deliberately obscure so it isdifficult for us to understand.

Their desire to get at the essence of things ledalchemists to distil plant and animal products. The

essences they produced might be oils, perfumes, orliquids with medicinal properties known as elixirs.One such liquid was alcohol, which was thought to bein some way a spirit. Hence the modern use of theword ‘spirits’ to indicate a drink with a high alcoholcontent, like whisky or brandy.

Alchemists invented furnaces for heating mixturesstrongly and melting metals, and the water bath, orbain-marie (named after a famous female alchemist,Mary the Jewess), for gentle heating over a longperiod. They invented pieces of apparatus which werethe forerunners of modern laboratory glassware, andthey discovered many useful chemicals, like the threemineral acids.

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Table 1 Astrological symbols for metals

Substance Planet Symbol

Gold Sun

Copper Venus

Mercury Mercury

Iron Mars

Vapour condenseson cool surface

Liquid runs downinto this channel

Mixtureheatedhere

Distillate runsout here

Heat Figure 1 An alembic

Mercury, a liquid metal, was named‘hydrargyrum’, ‘water-silver’; hence thesymbol Hg.

Robert Boyle and IsaacNewton werealchemists as well asscientists.

Ben Jonson, acontemporary ofShakespeare, wrote hisplay The Alchemist in1610. Its plot involvedfake alchemists.

Key substancesdiscovered or refined bythe alchemists includeglass, the three mineralacids (hydrochloric,nitric and sulphuric),‘sal ammoniac’(ammonium chloride),alcohol, alum,phosphorus and alkalis.

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Left: Two earlysixteenth-centuryalchemists standingbehind alchemicalapparatus designed todistil liquids

Alchemy was not a scienceAlchemy was not a science with a rational set oftheories tested against the experimental evidence.Alchemists certainly had theories, but they tended totry to make the experimental facts f it them ratherthan the other way round. They made little progressbecause they stuck to a pre-existing set of theoreticalideas and were reluctant to communicate theirfindings publicly. These two failings, as we would seethem, were to them the whole point of alchemy.

Alchemical authoritiesAlchemy looked backward to the ideas of ‘author-ities’: learned men and women who, it was thought,had possessed a knowledge lost long ago. This couldonly be recovered by devotion to their ideas andattempts to rediscover their ‘secret’. Present-dayexpressions like, ‘The secret of successful revision is…’hark back to this attitude of mind. By ‘secret’ or ‘art’we mean a technique passed on by word of mouth, orperhaps by apprenticeship to a more experienced andwiser person.

Alchemical secretsAlchemists thought there was a bright and wonderfulsecret at the heart of alchemy. This secret was not tobe revealed to ordinary people who might not havethe strength of character or nobility to stop themfrom abusing that knowledge.

It is worth noting that in the twentieth centurymany of the scientists who worked on the Los Alamosproject were worried about the potential evil uses of atomic energy. Today, we are concerned aboutthe potential misuses of genetic engineering. Thedifference is that these are, more or less, openlydebated and that publication and peer review allowscientists to share knowledge and keep each other upto the mark. Thousands of alchemical experimentswere needlessly repeated time and again.

Alchemy and chemistryWas alchemy the beginning of chemistry? Opinionsvary, but although alchemy contributed nothing tothe all-important theoretical basis of modern science,it did produce or isolate a number of key substancesfor the first time. Alchemists also developed practicaltechniques which are still being used in the twenty-first century.

John Tucker teaches chemistry at St Edward’s, Oxford and is anexaminer.

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Box 2 The lure of goldBeing an alchemist was expensive: there were allthose unusual pieces of glassware to be paid for aswell as rare, highly priced chemicals from theOrient. To be one, you needed either a wealthypatron or a private income. The famous painting byWilliam Fettes Douglas shows an old manexplaining the significance of a flask of gold-coloured liquid to a rich nobleman or merchant.

The lure of unlimited quantities of gold allowedconmen to swindle greedy people by a variety ofsimple tricks. One scam was to coat a small pieceof gold in black wax so that it resembled anordinary metal. During a long ritual, this blacklump was put into a crucible in the furnace, alongwith the last few drops of the all-important elixir.The wax would melt, of course, and burn away,leaving the ‘miraculous’ piece of gold. Suchcharlatans gave alchemy a bad name; although itdid not help matters that genuine alchemistssometimes resorted to similar frauds.

Box 3 Alchemy websitesLook up the following websites to find out moreabout alchemy:http://en.wikipedia.org/wiki/Alchemy www.levity.com/alchemy/index.htmlwww.pbs.org/wgbh/nova/newton/legacy.html

In Britain, it was notunusual for a clergymanto be a secret alchemist.Very likely he wouldhave inherited wealthand could subcontractcurates to do his parishduties, leaving him withplenty of time to pursuethe ‘Divine Art’, as itwas known.

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During the SecondWorld War, the topsecret Los Alamosproject built the USA’sfirst atomic bombs.

Above: ‘TheAlchemist’ by WilliamFettes Douglas