The halogens, of which the element fluorine is the first and most reactive example, have quietly insinuated themselves into our lives. Like a night nurse, they go about their business dosing us up without our agreement, muttering as they go, ‘it’s for your own good’. Water is chlorinated and fluoridated, bromides are prescribed, table salt is iodized. We are never consulted, but we know the words. These simple medicaments have a primal quality that encourages us to reach for them as readily as we once reached for hyssop or rue. The bromide, or Bromo-Seltzer, features in hard-drinking American literature almost as often as the bourbons and martinis whose effects it is there to assuage. In Tennessee Williams’s A Streetcar Named Desire, the alcoholic Blanche DuBois clutches her head and announces to nobody in particular: ‘Sometime today I’ve got to get a bromo.’ In Ernest Hemingway’s The Snows of Kilimanjaro, a man dies at length on the mountainside because he has failed to put iodine on his injured leg. The cause of death, it is made clear, is not the original accident but the man’s failure to apply treatment; it seems he subconsciously chooses death because it offers him an escape from that worst of Hemingway fates, the forming of a mature human relationship. Iodine was a miraculous disinfectant but it delivered a salutary sting. ‘No humanitarian nonsense about iodine,’ as the cynical adventurer Mark Staithes winces approvingly in Aldous Huxley’s Eyeless in Gaza while being treated for a similarly testing injury. Leonard Cohen’s 1977 song ‘Iodine’ gains its sense from this womanish contrariness of the element in medicine–stinging one minute, soothing the next.
General Ripper was right about one thing. Fluoridation did begin in America just as the Second World War was ending. In December 1945, Grand Rapids, Michigan, became the first city to be supplied with fluoridated water. A nearby city was designated as a control in what was to be a ten-year trial of its long-term effects on dental health, but fluoridation was preemptively declared a success and rapidly extended to other metropolitan water supplies including the control city, thereby ruining the experiment. Well over half of Americans drink fluoridated water today–as near to free universal health care as that country comes, perhaps. The programme has been resisted by the libertarian John Birch Society and many other lobby groups. Accusations of conspiracy have been traded ever since: that fluoridation was a scheme solely dreamt up so that the aluminium industry could dispose of the large quantities of fluorine compounds used in the metal’s manufacture; that it was funded by the sugar industry to get themselves off the hook for rotting people’s teeth; and, because fluoridation in McCarthy-era America was backed by the government, that it was the anti-fluoridationists, ironically, who were the left-wing stooges. The objection on principle has been mostly not about the efficacy of fluoride in preventing dental disease, but directed towards the cavalier attitude of officialdom in compulsorily imposing blanket ‘treatment’ without the normal medical precautions of prior diagnosis, prescription and determination of dosage. Some European countries have discontinued water fluoridation and have introduced optionally purchased fluoridated salt and toothpaste in its place. Meanwhile, the people of the United States still unexpectedly comprise one of the most comprehensively fluoridated populations in the world, and controversy continues to flourish, with one typical website terming fluoridation ‘medically evil, as well as socialistic’.
There never was a campaign against bromides, salts once so widely employed as all-purpose sedatives that the very word still retains humorous connotations of sexual underperformance. Although they had enjoyed great favour, they were withdrawn from the American market without fuss in 1975. By this time, so many dangerous side-effects had come to light that they earnt their own diagnostic description: bromism.
Bromides had begun to gain a reputation as a remedy more than a century before. In 1857, Sir Charles Locock, the physician-accoucheur who had attended Queen Victoria at the birth of her nine children, having heard that epileptic patients treated with bromide also experienced reduced libido, decided to try it on women suffering from ‘hysterical’ disorders. The amusingly named Locock shared the expert opinion of the time that epilepsy was linked to masturbation, nymphomania and other manifestations of ‘excessive sexual excitation’, and reasoned that, since his women appeared to be at their most disturbed during menstruation, the bromide treatment might also be an effective way to suppress the lustful desires that were supposedly troubling them. Proven to be effective as both anticonvulsant and anaphrodisiac, bromide seemed to confirm a link between epilepsy and onanism, and it began to be prescribed wherever a general dulling action was required. When the American humorist Gelett Burgess divided the world into two types, the sulphites and the bromides, in his 1907 book Are You a Bromide?, the term was widely understood to refer to a bore–sulphites, presumably, were people who by contrast brought a certain pungency to the table.
The same salt, potassium or sodium bromide, was also the active ingredient in the ‘bromos’ called for by Blanche DuBois, W. C. Fields and other high rollers. The generic term evolved from Bromo-Seltzer, a commercial antacid sold in the form of a fizzy powder developed by Captain Isaac Emerson of Baltimore, Maryland. The splendid Florentine Bromo-Seltzer Tower still stands in the city, the twelve positions on its clockface spelling out the name of the drug. The brand persists although the product no longer contains any bromine, while the tower has been converted into writers’ studios where a new generation can nurse their hangovers.
Iodine, though the elemental equal of fluorine, chlorine and bromine, appears to us not only as less dangerous than its halogen fellows but even as something of a beneficence. Iodized salt is just as widespread in America as fluoridated water, yet its introduction from the 1920s never aroused libertarian passions. Its familiar medicinal form is tincture of iodine, simply the element in alcoholic solution. Brown liquid in a brown bottle, it seems pure unction, its heady aroma and staining colour like a kind of vanilla essence for external use only.
Iodine is one of the great accidental discoveries of science. In 1805, Bernard Courtois took over the running of his family’s loss-making saltpetre factory in Paris while his father was in debtors’ prison. Although the Napoleonic Wars had begun, Paris was at peace after the years of revolution, and there was little local demand for his explosives. Nevertheless his raw material, in particular the guano from which saltpetre is most conveniently made, was becoming increasingly hard to obtain. Courtois struggled to keep the business going, preparing saltpetre (nitrate of potassium or sodium) instead from wood ash. When even wood ash ran short, he turned to seaweed, traditionally harvested from the Brittany and Normandy coast for its soda, which was used in the making of glass. One day in 1811, he noticed some corrosion of the copper vessels in which he mixed seaweed ash with other ingredients to make the saltpetre. By experiment, he found that the pitting arose during the furious reaction that occurred when sulphuric acid was added to the alkaline soda. This reaction, he couldn’t help noticing, also released puffs of an entrancing violet vapour. Investigating further, Courtois found that the vapour did not condense to a liquid but formed unfamiliar black, metallic-looking crystals. Courtois suspected he might have discovered a new element, but lacked the equipment to make tests and could not afford to take the time from his business. Instead, he asked two friends to finish the work. One of them, the gas chemist and balloonist Joseph-Louis Gay-Lussac, proposed the name iodine in analogy to chlorine.
By a strange chance, Humphry Davy was also present at the christening if not the birth. Since 1792, it had been difficult for British travellers to enter France, but Davy, who had been awarded the Napoleon Prize, was personally granted a passport by the emperor in order that he might collect his award. In October 1813, the newly married Davys, with a nervous young Michael Faraday acting as their footman, embarked at Plymouth on a ship used for the exchange of prisoners of war and set sail for Brittany. After a rainy voyage, they landed in enemy territory and were searched, even including their shoes. As they progressed towards Paris, they found the kitc
hens filthy but the food surprisingly agreeable. Davy had high hopes ‘through the instrumentality of men of science, to soften the asperity of national war’, but seemed unwilling to make the first move: at the Louvre he averted his eyes from the paintings lest he felt obliged to pay a compliment to his hosts. Jane Davy, meanwhile, shocked passers-by in the Tuileries Gardens with her unfashionably tiny hat.
Davy met with Ampère, his correspondent who had warned him of the dangers of nitrogen trichloride, and who had obtained some of Courtois’s new substance. Using his travelling set of chemical apparatus, Davy subjected it to analysis and concluded with Gay-Lussac that it was indeed a new element, and related to chlorine. Davy annoyed Gay-Lussac by firing off a paper to the Royal Society to this effect, while Davy felt the Frenchman had merely asked him in the first place in order to pick his brains. However, it was all smiles when, towards the end of his two months in Paris, Davy was honoured to be made a corresponding member of the French Academy of Sciences. The Davys did not meet Napoleon himself, but they did visit the Empress Josephine at Malmaison before pressing on to Italy, Switzerland, Austria and Germany, returning home in April 1815, a few weeks before the Battle of Waterloo. Somewhere en route, Davy must have revised his opinion on the ‘asperity of national war’, for soon afterwards he wrote to the Prime Minister, Lord Liverpool, urging severe treatment for the French under the terms of the peace treaty.
After 1815, as the demand for saltpetre fell still further, Courtois sought to profit from his discovery of iodine, manufacturing the element and various compounds, using chlorine gas to displace the iodine in the liquor obtained from kelp ash. But he was again unlucky, soon overtaken by more efficient processes. Fame ultimately eluded him, and he died penniless in 1838.
Following Courtois’s discovery, iodine was soon identified in seawater and in various mineral sources and was recognized to be effective in treating goitre. This revelation explained the traditional remedy of using burnt sponges or kelp to treat the swelling. The kelp ash industry that had been established along the weed-strewn rocky coasts not only of northern France but also of western Scotland had gone into decline when vast deposits of soda and potash were discovered in Spain and South America, but now it enjoyed a brief revival producing iodine for medicine. This business provided a meagre subsistence for crofters who kept kelp fires burning summer long to produce the iodine-laden ash. Entrepreneurs sought to put this activity on an industrial footing, with Glasgow becoming the centre. In 1864, the first factory on Clydebank was one erected in order to process thousands of tonnes of kelp brought up the river each year from the Scottish islands. But in an echo of what had already befallen the saltpetre industry, this labour-and energy-intensive process became uneconomic overnight when iodide deposits were found in Chile.
Although my nearest coastline is the flat sand and mud of East Anglia, where the seaweeds are not so lush as on rockier shores, I decide I should have a go at making my own iodine. I read careful instructions that I should select only this kelp or that laminaria, but, slipping among the tidal pools on a freezing December day, it is hard enough to distinguish one species from another at all. With numb hands, I randomly scoop up a bucketful of wrack and take it home to dry, spread out by the boiler. After several weeks, I have 400 grammes of dried weed, which I place in an open ceramic bowl in the fire. Orange flames from the sodium in the brine dance lazily as it burns, and afterwards I am left with just sixty grammes of a crispy grey ash. I pound this to a powder and stir into it a minimum of water to create a runny black sludge, which in turn I place in a funnel with a filter paper. A clear liquor trickles from the spout, rich with marine salts. Most of the solution will be sodium chloride, of course, but bromide and iodide should also be present. Seaweeds are efficient at concentrating these elements. The concentration of iodine in seawater is less than a hundred parts per billion, but in seaweed it can be several thousand parts per million, a hundred thousand times greater. I allow the filtrate to stand for a few days, during which time an impressive quantity of white salt crystallizes from the solution.
Now it is time to attempt the conversion of the colourless iodide into the gaudy hues of the pure element. Like Courtois, I add a splash of sulphuric acid and follow it with a good quantity of hydrogen peroxide (not terrorist grade, but fairly strong) which should oxidize the acidified iodide to iodine. I shake the mixture to speed it on its way and see the liquid begin to colour. Pale yellow darkens through shades of saffron and settles after a few minutes to the colour of stewed tea. I am truly amazed. I have never attempted the experiment before and have been entirely careless in collecting my raw material, but I have my iodine. Or nearly–this rich brown is due to iodine mixed with iodide salts. I still want to see the brilliant violet vapour that astonished Courtois.
I decant the brown liquid and shake it up again with carbon tetrachloride. This sweet-smelling but unlovely chemical–carcinogenic and ozone-depleting–is practically unobtainable these days, but I have found some in my father’s comprehensive selection of dodgy solvents. It does not mix with water but preferentially dissolves the iodine. In this very different solvent, I see for the first time the characteristic colour. Violet is the right word: it is far beyond mauve in intensity, yet lacks the sinister depth of a purple. I say a quick mea culpa for the sake of the ozone layer and allow the carbon tetrachloride to evaporate, leaving behind a black film on the glass. These are tiny iodine crystals. They emanate a faint pungent smell, similar to but less acrid than chlorine, not entirely unpleasant, the kind of smell that we now think of as medicinal, retrospectively applying our cultural knowledge that the halogens are used as disinfectants. I apply gentle heat to the crystals, and watch as the first pink wraiths begin to rise up in the test tube. Soon the solid is gone, and all that remains is an intensely coloured swirling vapour, which recondenses on the cooler parts of the tube–the same pure element, its atoms reconfigured in new black crystals. When Johann Wolfgang von Goethe performed the same experiment for the amusement of some house guests in 1822, he delighted in the support it gave to his influential theory of colours, which held that reds and yellows were related to white while the ‘cool’ colours at the violet end of the spectrum were derived from black.
Slow Fire
If a person today knows only one chemical formula, it is sure to be H2O, the formula for water, a compound comprising two parts of the element hydrogen to one of the element oxygen. In the eighteenth century, however, neither H nor O was known, and water itself was still widely believed to be one of the irreducible elements of which all matter was composed.
Ever since Aristotle, water had seemed the most secure of the four elements. On the occasions when philosophers and alchemists thought to question the theory, it was fire (which needed to feed on other elements in order to sustain itself), or earth (which so obviously comprised many distinct substances), or air (which might be nothingness itself) that gave them trouble. Water at least tended to look and feel like water, and remained the element most clearly linked to its ‘principles’ or fundamental properties of being cold and moist. Yet water was a puzzle too. It might appear constant, but waters from different sources often tasted very different, ranging from strangely refreshing to quite undrinkable.
Modern science had reason to investigate the nature of this Aristotelian element more closely. In the growing cities, sanitation was non-existent and clean water always in short supply. Utopian fictions always include a bountiful supply of pure fresh water on their inventory of benefits. The principal river of Thomas More’s Utopia (1516) is the Anyder, its name derived from the Greek for ‘no water’, just as More’s coinage of ‘utopia’ means ‘no place’. The strangely Thames-like tidal river is no use for supplying the city with drinking water, which More describes as being brought instead by elaborate means of channels and cisterns. Francis Bacon’s New Atlantis (1624) goes a scientific step further and imagines the purification by osmosis of water into ‘pools, of which some do strain fresh water out of s
alt, and others by art do turn fresh water into salt’.
Hazily, the generation of natural philosophers who came after the alchemists began to understand that the quality of water mattered to public health. What drove them was not only a sense that filth contaminating the water was a cause of illness, but also a belief that certain substances added to it might make it positively health-giving. Out of this work by turns would emerge science’s understanding of acids and salts as well as the isolation of water’s gaseous ingredients, hydrogen and oxygen.
In 1767, the thirty-four-year-old nonconformist minister Joseph Priestley returned from one of his regular long visits to London to settle in Leeds, the city of his birth, and moved into a house adjacent to a brewery. A man of huge intellectual curiosity, he had written biographical and scientific histories, published pamphlets critical of Britain’s policy towards its American colonies and challenged congregations by preaching his unorthodox variety of Christian belief. However, inspired by meetings in London with Benjamin Franklin, Priestley now found his true métier in experimental science. Moving to Leeds, it was only natural that he should turn his attention to the constant bubbling of the recently identified ‘fixed air’, emanating from the beer mash next door.
Priestley made a systematic study of the properties of this gas, noting that it would extinguish a flame and cause the asphyxiation of animals, but that plants thrived in it. He convinced himself that the gas had a beneficial effect against ailments such as scurvy, which led him to consider whether a convenient means could be found to administer it. By sloshing water from glass to glass over a tub of the brewer’s barley mash, he discovered that some fixed air would dissolve in the water and realized that he had his answer. Priestley devised a general means of making the effervescent drink–for those not blessed to have a brewery on their doorstep–and in 1772 published ‘Directions for Impregnating Water with Fixed Air’, based on reacting sulphuric acid with chalk and then bubbling the gas released through ordinary drinking water. He suggested that the fizzy liquid that resulted might have both therapeutic and military applications.
Periodic Tales Page 14