Periodic Tales

by Hugh Aldersey-Williams

  The Chinese obtained mercury metal readily enough from the abundant red ore cinnabar, and this pigment has itself permeated the culture in the form of the ubiquitous vermilion that is regarded as a uniquely auspicious colour. Cinnabar was strewn in graves to restore colour to the cheeks of the dead, and as early as the Shang Dynasty, 1600 BCE, it was being used to make ink with which to tint the Chinese characters incised in pieces of bone. The metal itself was used as an alternative liquid to drive water clocks or in mechanized armillary spheres. It was even used to make tumbling toys. ‘The Chinese have probably used mercury and cinnabar more extensively than any other people,’ according to the great sinologist Joseph Needham in his twenty-four-volume Science and Civilisation in China.

  A modern mercury cascade with its own message of life and death was created by Alexander Calder for the Spanish Pavilion at the 1937 Paris Exposition. The American artist received the commission indirectly from the short-lived republican government in the midst of Spain’s civil war, and his Mercury Fountain duly went on display in the same space as the documentary masterpiece of those years, Picasso’s Guernica. Calder’s work is more oblique in its reference to the conflict. The mobile sculpture consists of a series of three metal plates arranged above a large pool of mercury. Mercury is pumped up so that a fine stream trickles on to the top plate. It quickens in droplets and rivulets across the plates in turn while they gyre and bow under the weight of the metal, before it vanishes quietly into the pool below. The mercury is the key to the meaning of the work. It came, like the majority of the world’s mercury at that time, from the cinnabar deposits at Almadén in Ciudad Real southwest of Madrid. This strategically important location was to be repeatedly besieged by Franco’s insurgents, and Calder’s work commemorates the miners who had successfully held off the first nationalist onslaught a few months earlier. In one of the most imaginative war memorials ever devised, we see bright lives aggregating, separating, shaping larger events, and those events in turn determining their fate, before their ultimate absorption into stillness.

  Almadén means ‘the mine’ in Arabic, and this site was well known to the Arabs who ruled Spain from the eighth to the fifteenth centuries. Calder’s fountain is an acknowledgement of this history too. In 936, at Medina Azahara near Córdoba, some hundred kilometres to the south of Almadén, the caliph Abd al-Rahman III began to erect a vast personal estate with a mosque and gardens overlooked by a sumptuous palace. An enchanting feature of this richly decorated alcázar, or palace complex, was a pool of mercury positioned such that it bounced bright shafts of sunlight round the interior of the room in which it was situated. Guests were able to dabble their fingers in the metal, enjoying its cool, enveloping touch, and sending wild dapples across the ceiling like an early version of a dance-floor glitter ball. Ornamental pools of mercury were a feature of Islamic high living, and there is evidence that they were also used in pre-Columbian America. Before the element’s poisonous qualities were known, it was natural in places where it was easily obtained to rejoice in the coursing, trickling, glittering quality of the liquid.

  When it was moved to the Joan Miró Foundation in Barcelona in 1975, Mercury Fountain was put on display in its own glass cubicle. No longer could visitors do as they had done in Paris and throw coins on to the liquid surface just to see them float there. It had in fact shown a remarkably lax attitude to public health that the viewers were allowed to enjoy such open access to it in 1937. Of the 200 litres of mercury that arrived from Almadén on the afternoon of the press opening of the Spanish Pavilion (Calder had used steel ball bearings to mock up the action of the sculpture as he worked on it), an astonishing fifty litres were to be held in reserve, said Calder, to take care of losses due to splashing and leakage over the course of the exhibition. The toxic effects of mercury–familiar as an occupational hazard of hatters and others who used mercury compounds in their work–are felt when it is absorbed through the skin or when vapour enters the lungs. Yet for admirers of Calder’s artwork there was not even Cocteau’s rudimentary precaution of latex gloves.

  The quarantining of Mercury Fountain is emblematic of what is happening to the element everywhere. From its beginnings as a decorative and mystical wonder, mercury went on to find many uses exploiting its exceptional combination of properties–density, fluidity, conductivity. Its compounds have been used as pigments and cosmetics. Their often poisonous nature suits them for insecticides and marine antifouling. In medicine, they have provided the active ingredients of everything from drastic syphilis treatments to routine laxatives and antiseptics such as calomel and Mercurochrome. But all these and many other applications are now falling into disfavour. On 1 January 2008, Norway banned all imports and manufacturing involving mercury, even including the making of dental amalgams. The European Union is to ban the export of mercury from July 2011 in an effort to reduce global exposure to the element. Mercury thermometers and barometers will become historical relics. Almadén has finally ceased production after more than 2,000 years of operation. With mercury stopped at its source, attention turns to what is already in circulation. A British study of cremations has even raised concern about the element escaping into the environment as the fillings in the teeth of the deceased are vaporized–the spectre of our once-easy coexistence with the metal come to haunt us.

  Soon only highly specialized applications may be left, although it is some consolation that one or two of these recapture the surreal delight of more ancient mercury amusements. In the mountains of British Columbia not far from Vancouver is the Large Zenith Telescope, which obtains its images of the heavens using a liquid mirror. Mercury is poured into a wok-like dish six metres in diameter. The dish revolves at a stately pace, forcing the surface of the mercury into a paraboloid more perfect than can be obtained by solid glass or aluminium. The idea had been around for more than a century, but it is only recently, as the metal was drawing opprobrium elsewhere, that it has become possible to create a sufficiently smooth-running mechanism to enable sharp images to be produced from such a mercury pool. Liquid-mirror devices must of course be held horizontal if they are not to spill their magical fluid. Constrained to gaze ever upward, these telescopes do not scatter sunlight but gather the light of the stars, offering a window not on the underworld but out on to other worlds.

  Many chemical procedures that were well known to the alchemists now lie beyond the bounds of normal scientific practice, not because they are especially complicated or obscure, but because they are regarded as so hazardous that modern health and safety laws will not permit them to be undertaken even with all the safeguards of a state-of-the-art laboratory. One of these procedures is the reversible combination of mercury and sulphur, a reaction that was central to alchemical theory. The alchemists’ interest in this simple reaction is easily explained. By putting yellow sulphur, which is dry and hot, together with liquid mercury, which feels cool and wet, they brought together the four principles of all matter.

  The colour of the sulphur and the bright gleam of the mercury suggested furthermore that gold might be the outcome of the fusion. The alchemists believed that all metal deposits in the earth were on their way to becoming gold; if a man found instead tin or lead he had simply come too early. With their auspicious appearance, mercury and sulphur, both frequently occurring in their native state, looked to offer a faster route to this goal. The great Arab alchemist and mystic of the eighth century, Jabir ibn Hayyan (his name often appears latinized as Geber), who may have been responsible for bringing Chinese knowledge of cinnabar and mercury to the West, believed that perfection in metals, whether found in nature or made by man, could only be achieved when these two elements were present in the correct proportion and at the right temperature. Lack of perfection–that is to say finding base metal when one hoped for gold–was simply explained as a disproportion of these factors. In Jabir’s view, the more precious metals were made by ensuring that a relatively greater amount of mercury was present. But there were further provisos to do
with the purity and type of each element used. Silver was to be made by combining mercury with what Jabir called white sulphur, for example, whereas gold was made from ‘best’ mercury with only a little red sulphur, though it is impossible to be sure exactly what he meant by these terms.

  That was the theory. Experiments proved disappointing, needless to say, although some disreputable practitioners managed to persuade a few credulous souls that they had at least increased the quantity of their existing gold through the addition of mercury and sulphur–the sulphur would have burnt off while the mercury merged with the gold by amalgamation, producing an apparent gain in weight, but of course no more gold. Rather than abandon their cherished hope, the alchemists elaborated Jabir’s theory in the light of these unsatisfactory results by suggesting that all manner of metals in addition to gold might be brought forth simply by juggling the relative proportions of these two elements. This reaction was therefore at the heart of mainstream science in medieval Europe, and remained core to alchemical thinking for several centuries. It was often performed and it enjoyed scholarly approval. One early seventeenth-century text shows an engraving of Thomas Aquinas pointing like a holiday tour guide towards an instructively cutaway turf-covered furnace in which the vapours of two elements intertwine. ‘As nature produces metals from sulphur and mercury, so does art,’ reads the caption. This reaction, though undertaken on the basis of erroneous belief, was nevertheless a key turning point on the road to modern chemistry. It was perhaps the first instance of the informed synthesis of a new substance from two known ingredients. Furthermore, it was the first clear demonstration of the reversibility of chemical reactions–for not only did mercury combine easily with sulphur to form mercury sulphide (cinnabar), but the mercury sulphide also, when heated, separated back into its two constituent elements–so providing an important hint that matter could be neither created nor destroyed.

  It is not a difficult experiment. I could easily cannibalize the mercury from an old thermometer, put it in a crucible, mix in an appropriate amount of sulphur, cover it, and heat it until the rich vermilion colour of mercuric sulphide began to appear. I could heat it again in order to separate these two constituent elements, distilling off the mercury as the sulphur burnt away. But, while I am sceptical of the advertised hazards of the many chemical experiments one is these days discouraged from attempting at home, I am aware now (as I wasn’t when I used to obtain my mercury by roasting dead batteries) that mercury vapour is deeply unpleasant stuff.

  I settle for witnessing the experiment at one remove with the assistance of Marcos Martinón-Torres at University College London. Marcos has carved out an academic career at the junction of archaeology and materials science that gives him a marvellous pretext for re-enacting the experiments of the alchemists in the interests of historical accuracy. When it comes to repeating the mercury–sulphur experiment, however, even he is banished from the laboratories of his institution and obliged to make himself scarce in a secret field hidden in the suburbs.

  The reaction vessel is a clay aludel–an Arabic word, like so many in chemistry–which is a kind of large crucible with a high pointed lid like a witch’s hat where vapours can mingle and cool. The contraption is about the size and shape of an ostrich egg. A small vent at the top prevents the pressure from building up inside the vessel and causing an explosion. Marcos and a colleague, Nicolas Thomas from the Panthéon-Sorbonne University in Paris, sprinkle the cinnabar they have brought into the bottom of the aludel, put the hat on and seal it shut with wet clay. Then they build a small furnace of bricks and clay and fill it with charcoal and light it. When they judge it is hot enough to decompose the cinnabar, but not so hot that the mercury will escape as vapour, they place the aludel in the furnace. Wearing breathing apparatus, they crouch at the field edge, watching the aludel carefully as the red heat of the fire begins to warm it. Relieved that it has not cracked, they soon observe small beads of mercury that have condensed around the vent hole. This is the sign that the reaction has occurred. They allow the vessel to cool and then break it open. A firmament of tiny bright globules has settled over the inner wall. By collecting the mercury, adding sulphur and heating once more, they recover the cinnabar, a yellow and orange mess, part solid, part melt, looking for all the world like a steamed treacle pudding but smelling of the devil.

  Part Two: Fire

  The Circumnavigation of the Sulphur

  Gold and silver, iron and copper all appear scores of times in the Bible owing to their monetary or utilitarian value. Lead and tin are mentioned in passing. These are six of the ten elements known from antiquity. One further element has a symbolic value of an entirely different kind, and that is sulphur, or brimstone as it is universally termed in English Bible translations.

  Brimstone earns fourteen mentions in all, and not one of them is complimentary. Its every appearance is accompanied by scenes of punishment and destruction or at least the threat of great violence. In Genesis, the depraved cities of Sodom and Gomorrah are overthrown when ‘brimstone and fire from the Lord out of heaven’ is rained upon them. Six of the references come in the central chapters of the book of the Revelation of Jesus Christ given to the Apostle John, and cover the Great Tribulation, the Return of the King, the Millennium and the Last Judgement. The sulphur starts to flow once the seven seals have been opened and six of the seven trumpets have sounded, and scarcely lets up until the New Jerusalem is revealed 200 verses later.

  In chapter nine of Revelation, John sees a third of humanity slain by an army of ‘two hundred thousand thousand’ horsemen. The riders have

  breastplates of fire, and of jacinth, and brimstone: and the heads of the horses were as the heads of lions; and out of their mouths issued fire and smoke and brimstone. By these three was the third part of men killed, by the fire, and by the smoke, and by the brimstone, which issued out of their mouths.

  Then the seventh trumpet sounds, proclaiming God’s kingdom in heaven. Satanic beasts rear their many heads, and an angel warns that anybody who worships the beast ‘shall drink of the wine of the wrath of God, which is poured out without mixture into the cup of his indignation; and he shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb’.

  Babylon falls, heaven rejoices, and Christ appears on a white horse. In the Battle of Armageddon that follows, the Devil and his accomplices are ‘cast alive into a lake of fire burning with brimstone’. Finally, John hears God pronounce sentence on the remainder of people who reject His word: ‘the fearful, and unbelieving, and the abominable, and murderers, and whore-mongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death’.

  God, or John, shows so little imagination in the forms of punishment administered during the last days that we must take it that fire and brimstone have a particular ritual significance. The fact that hellfire is always accompanied by brimstone, that brimstone is never present without fire, indicates not only that brimstone is flammable but also that there is something specially horrific about its flame. Milton was well aware of these properties, which are crucial in setting the opening scene of Paradise Lost, where we find the Devil cast out from heaven in

  A Dungeon horrible, on all sides round

  As one great Furnace flam’d, yet from those flames

  No light, but rather darkness visible

  Serv’d onely to discover sights of woe,

  Regions of sorrow, doleful shades, where peace

  And rest can never dwell, hope never comes

  That comes to all; but torture without end

  Still urges, and a fiery Deluge, fed

  With ever-burning Sulphur unconsum’d.

  For sulphur burns not like a candle, but with a low blue flame that is barely luminous–‘darkness visible’ indeed. It is not rapidly consumed like a wood fire, so that it is easy to imagine the flame as ‘ever-burning’, especially if the ignited su
lphur occurs, as it sometimes does in nature, in a seam that runs endlessly and invisibly into the earth.

  Could this dreadful material really be the same as the sulphur I’d once seen stacked up on the docks at Galveston in Texas? Lemon-yellow bricks of the stuff, each the size of a container truck, were arrayed several high and several deep, the cheerful colour making them look more like an unusually successful piece of public art than a vital industrial commodity awaiting shipment. The substance was the form of the element purified by sublimation–that is, by condensing the solid directly from the vapour–known quaintly as flowers of sulphur, and in the spring sunshine ideas of hellfire and damnation were very far away.

  Elemental sulphur is bland enough; its disagreeable alter ego is only awakened when it undergoes chemical change. The simplest reaction is combustion, which produces the corrosive, bleaching and choking gas sulphur dioxide. Its effect is cleansing as well as burning–something that obliges us to begin to differentiate between simple fire, which is destructive, and biblical brimstone, whose burning stench can also be purgative: perhaps through the action of sulphur even Satan might be redeemed in his former guise as Lucifer, the angel who fell from heaven. In antiquity, sulphur was widely used as a disinfectant and for related ritual purposes. When Odysseus returns to Ithaca and slaughters the suitors who have been pestering his wife, Penelope, he orders the nurse to ‘bring some sulphur to clean the pollution, and make a fire so that I can purify the house’. Sulphur is still sold for this purpose today, the suggestion being that you use it in the greenhouse rather than to dispel unwanted personal attention. Sulphur fires were used to combat cholera into the twentieth century, and sulphur was taken internally for digestive and other complaints. Mrs Squeers holds ‘brimstone-and-treacle mornings’ at Dotheboys Hall in Dickens’s Nicholas Nickleby, the filthy mixture administered, as she explains, ‘partly because if they hadn’t something or other in the way of medicine they’d be always ailing and giving a world of trouble, and partly because it spoils their appetites and comes cheaper than breakfast and dinner’.