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Summer 2008, Vol. 26, No. 2Feature
Powerful Effervescence
By Emily PawleySparkling mineral waters of the 21st century are up-market drinks: Vichy, Evian, and Perrier persist as symbols of taste and class. More than just a drink, however, sparkling water represents one of the last vestiges of the therapeutic mineral springs that were a mainstay of Western medicine for more than two millennia. The story of their rise and fall is not only the hidden underpinning of the massive modern-day soft-drink industry but also the story of a growing alliance between chemistry and medicine that would reshape Western therapeutic practice. In June 1772 the radical minister Joseph Priestley (1733–1804) described the details of a process that would eventually win him the Royal Society’s highest award, the Copley Medal. He had dripped a little oil of vitriol (sulfuric acid) on a mixture of chalk and water, caught the fixed air (carbon dioxide) that fizzed from the chalk in a bladder, and bubbled the fixed air through a column of water, which he then agitated at intervals. The resulting substance was, Priestley wrote, “an exceedingly pleasant sparkling water, resembling Seltzer water.” Histories of the soft-drink industry often begin with this moment—one of the earliest simple methods of making what we now call carbonated water. Historians of chemistry also refer to it as a significant event in the development of pneumatic chemistry (the 17th- to 19th-century study of gases). Like many of his fellow chemists, Priestley was busily elaborating the recent discovery that air, previously considered a single element (one of only four), was composed of different elements. Soon after his work with mineral water he was credited with the discovery of what he referred to as “dephlogisticated air,” a substance that Antoine-Laurent Lavoisier would soon afterward famously dub “oxygen.” But for Priestley, effervescent water was not merely a pleasant drink, nor was it merely a philosophical problem. Instead of creating a new substance, he was imitating an old one. In particular, he was attempting to re-create the naturally sparkling mineral water that emerged from the renowned “Vapor Cave” of Pyrmont near Hanover, Germany. (The seltzer water he refers to is not the modern bottled product, but the waters from the springs of Seltzer, Germany.) Moreover it was not the particular taste of Pyrmont water that Priestley sought, but its effect on the body. For Priestley, as for his contemporaries, water was a medicine. Water as MedicineFor centuries Europeans tapped their remarkable and varied landscape of natural springs for mineral water. Hot springs like those at Vichy and Bath offered waters warmed by geothermal heat or contact with magma; others like those at Naples were remarkable for their aching coldness. Some were salty, others tasted (and smelled) like sulfur, alkali, or iron. Finally—and perhaps most mysteriously—some, like those from the cities of San Pellegrino, Seltzer, Pyrmont, and Vergèze (the source of Perrier), had the pleasant acidic taste produced by bubbles. Our word spa comes from the town of Spa, Belgium, whose “chalybeate,” or iron-bearing, waters were used medicinally for 400 years. Clues to the springs’ importance remain in the names of modern cities that were founded on springs: Carlsbad and Wiesbaden (Bad means “bath” in German), Baden-Baden, Tunbridge Wells, and of course Bath. Records of hydrotherapy and balneology, the medical use of waters and baths, stretch back to classical antiquity. Greek and Roman Hippocratic physicians used sequences of hot and cold baths to balance and harmonize the humors of their patients. Pliny the Elder and Vitruvius listed springs with exceptional qualities for treating diseases of the sinews, joints, urinary tract, and skin. Ailing Romans drank from alkaline springs to rid themselves of tumors and from acidic springs to destroy gallstones. The elaborate ruins of Roman bath complexes in Baden, Switzerland, and Aquae Sulis in Great Britain (now the town of Bath) attest to the intensity of the Romans’ interest in hydrotherapy. Although Hippocratic medicine temporarily declined during the Middle Ages, the use of mineral springs continued. “Holy wells,” first associated with pagan divinities and later reassigned to Christian saints, took the place of the Roman baths. The Renaissance revival of Greek medicine brought old springs back into prominence. Later, during the early modern period, the rise of so-called chymical medicine produced new justifications for old practices by encouraging the therapeutic prescription of minerals and metals. By the 18th century springs had become places of fashionable resort, where genteel and aristocratic visitors met to dance, promenade, and “take the waters.” In Bath a seasonal crowd of tourists drank and soaked in what we now know to be a mildly radioactive soup of potassium, lead, iron, strontium, calcium, magnesium, bismuth, and sulfur. Indeed, English towns like Harrogate and Epsom existed solely to support their springs, and therapeutic drinking waters from Carlsbad (in what is now the Czech Republic), Eger (in Hungary), Seltzer, Spa, and Pyrmont were regularly shipped around Europe in bottles. Manufactured WatersGiven the immense sums invested in and derived from mineral springs, it is no surprise that generations of chemists, including such well-known natural philosophers as Robert Boyle, Friedrich Hoffmann, and Stephen Hales, attempted to explain what made each spring unique. Moreover, when the earliest chemical analyses revealed familiar materials like iron, niter, vitriol, sea salt, and alum, it was certain that attempts to imitate or even outdo nature would soon follow. Perhaps the most spectacular of these imitations was “the Duke’s Bagnio,” or “New Spaw.” This Turkish bath, established on London’s Long Acre by Samuel Haworth, the duke of York’s physician, featured artificial mineral waters that appeared to bubble from the ground. Soon after the opening of the Bagnio in 1685, Robert Boyle published an essay on “the imitation of Natural Medicinal Waters, by chymical and other wayes,” which he intended to “help the Physician to guess at the quality and quantity of other ingredients that impregnate the Natural Water proposed.” In 1698 the botanist Nehemiah Grew commercialized Epsom salts (magnesium sulfate) as a simple and lasting re-creation of the mineral waters at Epsom, then drunk as a purgative and famed for their efficacy against ulcers. To this day Epsom salts are used as a foot soak and drunk as a remedy for constipation.
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