Andrew Robinson enjoys a chemical romp from aluminium to zinc.
Periodic Tales: The Curious Lives of the Elements/A Cultural History of the Elements, from Arsenic to Zinc
- Hugh Aldersey-Williams
The familiar metallic taste of blood was explained scientifically only in the mid-eighteenth century. An Italian chemist and physician in Bologna, Vincenzo Menghini, roasted the blood of various birds, fish and mammals, including humans. He powdered the residue and passed a naturally magnetized lodestone close to the dried blood particles. Some were magnetically attracted, suggesting the presence of iron.
Science writer Hugh Aldersey-Williams successfully repeated Menghini's experiment in his kitchen using blood from chicken livers, a low oven and a moderately strong magnet. But why, he asks, did Menghini imagine that iron would be present in blood? The physician must have known that people with blood disorders were sometimes advised to take iron salts. In the sixteenth century, a principal iron ore was named haematite — the prefix 'haem' being derived from the Greek for blood. Western alchemists paired iron with the red planet Mars. The original connection between iron and blood seems to date to the Romans, who associated the two in their cult of the war god Mars.
Other entertaining elementary experiments conducted by the author involve phosphorus and iodine. Doubting the claim that rotting herrings emit light, he left some decaying fish in his garage. Two nights later, he observed the phosphorescent “glowing of the lifeless herring”, mentioned by twentieth-century writer W. G. Sebald. Using local seaweed, Aldersey-Williams also prepared an intense violet vapour and black crystalline condensate of iodine. Here, he notes, he followed the poet Johann Wolfgang von Goethe, who in 1822 demonstrated iodine vapour and crystals for house guests in support of his controversial theory of colours.
For all its technical accuracy, Periodic Tales is neither a book of experiments nor a science book. Aldersey-Williams eschews the territory covered, for example, by Peter Atkins in The Periodic Kingdom (Basic Books, 1995). There are few references to atomic weight and atomic number, scarcely any chemical formulae and nothing on electrons and orbitals. There is no up-to-date periodic table among the quirky illustrations, merely the handwritten version created by Dmitri Mendeleev in 1869. Instead, the book is a cultural history of some of the chemical elements, dwelling on both their material presence in our lives and their figurative presence in art, literature, language, history and geography. Thus we come to know the elements individually, argues Aldersey-Williams, who regrets that his own formal chemistry education did so little to acknowledge such a “rich existence”. So do I.
Aluminium, for example, was first named aluminum by Humphry Davy, who repeatedly tried to isolate it from its oxide, alumina. He followed the naming precedents set by platinum, molybdenum and tantalum. Then, in 1812, an anonymous reviewer of Davy's book Elements of Chemical Philosophy insisted on a name that sounded more “classical” — aluminium. Nonetheless, when use of the metal took off in the United States at the end of the nineteenth century, Americans plumped for the version that omits the letter 'i'. Not even the US literary critic H. L. Mencken could work out why in his 1919 book The American Language.
Aluminium enjoyed a brief mid-century vogue as a precious metal before the invention of the electrolytic separation process in 1886, still used today, which extracts it from bauxite (named after Les Baux in Provence, France, where the ore was found). In 1855, a French chemist, Henri Sainte-Claire Deville, managed to extract the metal by heating anhydrous aluminium chloride with sodium.But this was hugely expensive. His ingots — worth a dozen times more than silver — were admired at the Paris Universal Exposition of 1855 by Emperor Napoleon III of France, who offered financial support to Deville. Such was the metal's rarity that a renowned goldsmith, Christofle, made hand-crafted aluminium jewellery and tableware, which was favoured at imperial banquets, and an aluminium rattle was given to the emperor's newborn son. Chemical elements, Periodic Tales emphasizes, can go in and out of fashion. Think of what happened to chromium plating.
Almost every page yields a nugget. The difficulty, however, is to find order and meaning. Aldersey-Williams settles for five sections, divided into chapters on one element or a group such as the halogens. 'Power' includes gold, iron, carbon, plutonium and mercury; 'Fire' includes sulphur, phosphorus, chlorine, oxygen and radium; 'Craft' — tin, silver, copper, aluminium and calcium; 'Beauty' — chromium, arsenic, vanadium, antimony and neon; and finally 'Earth', encompassing the rare earth elements and some other, less familiar ones. This division is workable, but I query some choices. Gold, for instance, surely belongs as much in 'Craft' and in 'Beauty' as in 'Power'. It also seems odd to omit a chapter on silicon, given its starring role in electronics.
That said, the book is imaginative and fun. Who can resist the information that an unofficial Dutch spectroscopic analysis of the five-euro banknote shows it to be impregnated with an anti-counterfeiting ink containing a little-known rare earth element — europium.
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