What is important about all this is that the social behaviour of atoms – the branch of science known as chemistry -depends largely on how many atoms there are in the outer orbit. It is as if atoms are more comfortable with filled orbits, and are constantly searching for partners to swap electrons and achieve peace. For example, if one atom has seven electrons in its outer circle, it behaves like a collector trying to fill that yawning gap on its shelf and snaps up any electron around.
Odor Decoder
ReplyDeleteby John Lanchester
http://www.nytimes.com/2006/12/03/books/review/Lanchester.t.html?pagewanted=all
Popular science books have a set form, which in its way is as strict as the sonnet. They begin with some personal history of how the author became interested in a subject, move on to an explanation of the generally agreed science of the subject, and then describe the specific angle taken by the author on the subject’s remaining mysteries. Add a judicious sprinkling of personal history throughout, and voilà, the formula covers everything from quantum physics to geology to evolution.
ReplyDeleteLuca Turin’s engaging new book follows this form, but doesn’t feel at all like something we’ve read before — which is a tribute both to its subject and to its author. “The Secret of Scent” is about one of the great mysteries in science, one that is not just under our noses (like all the best mysteries), but actually inside the nose. That mystery is smell, and specifically the way the brain interprets molecules as smells. No two molecules, however similar their chemical structure, smell identical. Why not? As Turin asks, “What is this chemical alphabet that our noses read so effortlessly from birth?”
Science thinks that it has answered this question, and that the answer has to do with the shape of a molecule: the geometric arrangement of its atoms determines its smell. Turin disagrees. He thinks smell is determined by something else; but to rush too quickly to his hypothesis would be to miss the fun of “The Secret of Scent,” most of which lies in the incidental details of the journey and in Turin’s sharply expressed opinions about more or less everything — Moscow in the ’80s, peer review in science, the modern university system and why biologists “were never the pick of the intellectual crop. I should know — I’m one of them.”
Turin has an extraordinary gift for writing about smell. Before he became interested in the science of smell, he was that rare thing, a brilliantly readable perfume critic. He is a biologist by training, based in London after a peripatetic career that eventually led him to the business of fragrance chemistry. He first fell in love with perfume while working in France, via an encounter with a Japanese perfume called Nombre Noir: “halfway between a rose and a violet, but without a trace of the sweetness of either, set instead against an austere, almost saintly background of cigar-box cedar notes. At the same time, it wasn’t dry, and seemed to be glistening with a liquid freshness that made its deep colors glow like a stained-glass window.”
Blimey. There is no unpretentious way of writing about smell; to describe it, a writer must take on trust the reader’s willingness to agree with referents and metaphors. It seems possible that a good few potential readers of “The Secret of Scent” will send the book windmilling across the room as soon as they encounter Nombre Noir. They would be missing out, because a reader willing to accept Turin’s way of writing about smell is in for a wonderful trip that roams from cut grass and strawberries to a “huge, velvety, fluorescent peach 30 feet in diameter, with fuzz on it as deep as pile carpet, like Magritte’s huge fruit inside a room,” to a “reference smell of scrubbed bathrooms, suggestive of black and white tiles, clean, slightly damp towels, a freshly shaven daddy.” Turin really is a poet of perfume, whether it’s Estée Lauder’s Pleasures, “about as bright as a perfume can be without actually giving you a tan,” or “the sunset glow of Jean Patou’s Joy,” or Le Male by Gaultier, “with its striking Glenn Miller barbershop timbre.”
We might seem to have wandered away from science; not so. The musks that give Le Male that wonderfully evoked fragrance would once have been derived from such sources as rock badger urine, dried blood of the alpine goat or feces of the pine marten. Now, thanks to a mistake made in 1887 by a chemist trying to create an explosive based on TNT, synthetic musks are commonplace in more or less everything that has smell added to it, from soap powder on up. This movement from smell to science to practical application is characteristic of Turin’s book, and some of the most interesting things in it have to do with the industrial and commercial uses of smells. Fragrance — fine fragrance — turns out to be only a small part of what perfumers do, since most of their work concerns functional products like bathroom cleaners and washing powder. The job is to prevent them from smelling nasty, and to do it on the cheap. Even for a fine fragrance, ingredients make up only 3 percent of the retail price. Those ingredients used to cost 200 euros to 300 euros a kilo (roughly $145 a pound); now they cost half that. In Turin’s view, “the cheapness of the formula” is the main reason most fine perfumes are lousy. “Other reasons,” he says, “include slavish imitation, crass vulgarity … and general lack of inventiveness and courage.”
ReplyDeleteTurin’s subject is fascinating and his prose is vivid, but that does not mean the science of the book is easy. As “The Secret of Scent” progresses, we learn more and more about the specifics of molecules and groups of odors, and why Turin believes that the generally accepted account of the smell mechanism is wrong. Turin thinks our sense of a molecule’s smell, rather than being based on its shape, comes from its wave vibration. This theory has been around for a number of decades but has suffered from the lack of a plausible mechanism by which it might work. Turin’s suggested mechanism is based on a quantum phenomenon known as “inelastic electron tunneling,” and it is no easier to understand than its name. The nose has (this was discovered in 1991) 347 scent receptors; these, he thinks, function as a spectroscope, each of them responding to a specific frequency of molecule, and translating them into what we perceive as a smell.
As Chandler Burr (now the perfume critic for The New York Times) made abundantly clear in his popular 2003 account of Turin’s work, “The Emperor of Scent,” these ideas are not generally accepted. Indeed, a review of Burr’s book in Nature said Turin’s ideas were “brazen: a universal theory of smell based on one man’s olfactory observations.” Part of the reason for the animus in the scientific world seems to have been the publicity attracted by Turin’s ideas: a blisteringly hostile editorial in the journal Nature Neuroscience, accompanying some research that seemed to refute Turin, said as much, citing the “extraordinary — and inappropriate — degree of publicity that the theory has received from critical journalists.” Notwithstanding that, Turin has founded a company that uses his ideas to create new molecules, with a success rate he says is a hundred times better than the industry standard. “I guess I’ll just carry on using my theory, credence or not,” he writes. Good for him. The general reader can’t adjudicate this kind of scientific dispute; though we’re likely to root for Turin, not least because it would be corking good fun if one of the great mysteries of science were solved by a nutty professor with a sideline in perfume criticism.