Book review / The right chemistry in Marilyn's bedroom

'The Consumer's Good Chemical Guide' - John Emsley: WH Freeman and Co, £18.99

In bed, Marilyn Monroe said, she wore nothing but Chanel No 5. It is hardly the sort of information you will find in the average chemistry textbook, which is a shame because all perfumes are a way of communicating with chemicals.

Created by le grand nez Ernest Beaux, Chanel No 5 contains an oil derived from the flowers of the ylang-ylang tree which grows in the Philippines. Somehow, such exotica seems fitting, but what is perhaps less well known is that the "top note" of Chanel No 5 is a purely artificial fragrance, called 2-methylundecanal, and its musky base note is the creation of chemists.

Musk deer used to be slaughtered by the thousand so that women could dab the secretions of the deer's anal glands behind their ears. Now most perfumes use the synthetic variety, leaving musk deer to forage in peace.

Bizarrely, there is a connection between the smell of musk and high explosives. The first artificial musk molecule was created in 1888, when the German chemist Adolf Baur slightly altered the chemical composition of TNT, and found that tert-butyl-trinitrotoluene smelt of musk. It became known as Musk Baur. But it was not until 1906 that another German, by the name of Walbaum, isolated the key odour component, muscone, as a white crystalline solid. Its proper molecular structure was only worked out in 19

26. But somehow one cannot imagine Marilyn ever saying to a man: "Wait there while I slip into some 3-methylcyclopentadecanone."

When I was at school we used a physics textbook called Physics is Fun, prompting the response from our chemistry teacher that the new text for his subject ought to be And Chemistry is Funnier. Alas, its title was something boring like Chemistry Takes Shape. John Emsley's book also lacks a snappy title, but it comes closest to fulfilling my old teacher's desire to have a book about chemistry that is fun to read.

The structure of the guide is enticing: it starts with smells, then sweetness, then the chemicals we drink, before discussing the ones we eat. Sugar, it turns out, is not the sweetest of chemicals: a molecule called thaumatin, extracted from ketemfe, a West African fruit, is about 3,000 times sweeter. But, Dr Emsley says: "It has the drawback of clinging to the tongue and the sweet sensation lingers too long."

This book is a polemical defence of chemistry and, by extension, of the chemical industry in the face of years of criticism by environmental lobby groups. Only in the penultimate chapter, which discusses carbon dioxide and global warming, does the polemic go a little too far. Dr Emsley rightly condemns the apocalyptic visions that global warming might lead to the melting of the Antarctic ice-cap and, also rightly, points to the inadequacies of current climate models. But the message from responsible climatologists has always been that there is a risk of global warming which they cannot yet predict, but if it is real, by the time the computers are able to model the effect it will be too late. We should, therefore, take precautionary action now, such as conserving energy (which is in any case desirable on other grounds). But this reasonable position is afforded less space than is its due.

This is, however, a minor quibble. Dr Emsley's book is a fascinating read, filled with interesting facts. What other chemistry book would include a discussion of aphrodisiacs? (Sadly, it appears that none of them work with the possible exception of chocolate, which makes even more risque those torrid TV ads). What other chemistry book would tell you lard is mainly unsaturated fat?

The word "chemical" has virtually become a modern obscenity, carrying connotations of pollution, cancer, and deformity. At first sight this is surprising, given that the products of chemical science and the chemical industry include such health-giving things as antibiotics and such health-enhancing products as aspirin and paracetamol.

The chemical industry is one of Britain's few remaining manufacturing success stories. So why are so many people antipathetic towards it? Perhaps because until Dr Emsley no one had thought that the right place to begin explaining chemistry was Marilyn Monroe's bedroom.