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Paul Strathern

MENDELEYEV'S DREAM

The Quest for the Elements


Book review by Anthony Campbell. Copyright © Anthony Campbell (2002).

Mendeleyev is famous as the discoverer of the Periodic Table of the elements. In spite of its title, however, this book is not only about Mendeleyev, but deals with the development in our understanding of the constitution of matter from early Greek times onwards. The notion of the four elements (earth, air, fire, and water) as the fundamental constituents of nature dates back to the pre-Socratics and was destined to persist as late as the Middle Ages and even beyond.

Chemistry emerged from alchemy only slowly and with difficulty. Strathern has little sympathy with alchemy, which he labels unscientific and irrational, and he certainly has no liking for the "philosophical" element in alchemy which so much intrigued C.G.Jung. Nevertheless, it is impossible to write a history of chemistry without an extended discussion of alchemy. This is a vast and obscure subject and I felt that Strathern's evident dislike of it occasionally led to an imbalance in his treatment.

In view of this antipathy to alchemy, it is surprising to find a complete chapter devoted to Paracelsus (Theophrastus Bombast von Hohenheim), the sixteenth-century Swiss physician who applied ideas derived from alchemy to therapeutics. This is quite interesting but is perhaps rather peripheral to the main story. Though his approach is generally skeptical, Strathern appears ready to take claims for the success of Paracelsus's treatments at face value. I also felt that too much space was allotted to Giordano Bruno, whose thinking was mystical rather than scientific and who was more concerned with cosmology than with chemistry. And although Galileo and Francis Bacon undoubtedly merit inclusion as scientific thinkers, their writings don't really have much to do directly with chemistry or the elements.

Chemistry, as opposed to alchemy, is often taken to have begun in the seventeenth century with Robert Boyle, who certainly merits the space accorded to him here. Indeed, the semantic change from alchemy to chemistry was set in motion by the title of Boyle's chief work The Sceptical Chymist. Unlike the alchemists, who shrouded their work in secrecy, Boyle wrote up his experiments clearly so that others could repeat them.

And yet, paradoxically, Boyle had not freed his thinking totally from alchemy after all, a fact that distresses Strathern. His secret coded notebooks reveal him to have been in persistent and extensive pursuit of the legendary Philosophers' Stone. He used his influence in the Royal Society to persuade Parliament to repeal the four-centuries-old anti-alchemy law on the grounds that the production of gold by alchemy would be of great benefit to the country, and he encouraged scientists throughout the land to pursue this important quest.

As is well known, Isaac Newton was likewise deeply convinced of the truth of alchemy and spent a vast amount of time and effort in its practice, although Strathern thinks that Newton was more metaphysical in his approach than was Boyle. Both Newton and Boyle were deeply religious, although Newton's religious interests were more esoteric than Boyle's and would have been considered heretical had they been widely known.

In 1661 Boyle defined an element as a substance that could not be broken down into simpler constituents. This was an important intellectual milestone in our understanding of chemistry. The seventeenth and eighteenth centuries saw a widespread enthusiasm for the discovery of new elements, including phosphorus (first isolated from human urine), chlorine, barium, molybdenum, nickel, and platinum.

Combustion had been a mystery from the time of the ancient Greeks. For many centuries it was explained in terms of the four elements, but in the second half of the seventeenth century a new theory came to be widely accepted. Combustion was now thought to be due to the release of phlogiston, a fire-producing substance contained in materials such as wood. But work by Henry Cavendish and Joseph Priestley led the French chemist Lavoisier to conduct experiments which disproved the phlogiston theory and culminated in the discovery of oxygen, previously identified by Priestley as "dephlogisticated air". Lavoisier was guillotined in the Revolution, and Priestley continued to believe in phlogiston for as long as he lived.

More new elements were discovered in the second half of the eighteenth and beginning of the nineteenth centuries, and John Dalton's work on the proportions in which elements combined led him to formulate his atomic theory. Building on this, the Swedish chemist Berzelius devised the notation system which we still use today.

By now it was becoming apparent to many chemists that there was some kind of order in the atomic weights and the properties of the elements, but attempts to establish the pattern kept failing. In his final chapter Strathern describes how Mendeleyev ultimately solved the riddle, apparently as the result of a dream. (It is interesting that another chemist, Kekulé, is also supposed to have found the solution to a chemical mystery, the ring structure of many organic molecules, as the result of a dream.) Mendeleyev's Periodic Table of the elements did not win immediate acceptance everywhere, but Mendeleyev was able to make detailed predictions of the properties of hitherto unknown elements and when these were subsequently discovered they were found to correspond to his predictions with impressive accuracy—a fine anticipation of Karl Popper's falsification principle.

This is a readable, if slightly tendentious, account of the development of our modern understanding of the nature of matter. Strathern misses out some good stories, such as an apparently convincing demonstration of transmutation witnessed by Helvetius in the seventeenth century, nor does he mention the strange story of the Rosicrucian Manifestos, which are thought to have influenced the thinking of both Boyle and Newton and to have played a part in the origins of the Royal Society. But the book provides an adequate overview of its subject and the characters and backgrounds of the principal figures in the story are well described.


%T Mendeleyev's Dream
%S The Quest for the Elements
%A Strathern, Paul
%I Penguin Books
%C London
%D 2000
%P 309 pp
%K chemistry, history of science
%O paperback
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