On the Connexion of the Physical Sciences

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few diagrams and lit- On the Connexion / tle mathematics. But of the Physical it is a masterpiece of Sciences MARY SOMERVILLE descriptive explana- John Murray: 1834. tion and analogy that unveils a complete scientific world view, covering everything from stars to insects. It was Murray’s best-selling scientific publication until Charles Darwin’s On the Origin PORTRAIT GALLERY NATL SCOTTISH

of Species in 1859; it eventually ran to ten MRS WILLIAM SOMERVILLE FAIRFAX, MARY editions in Britain, and was published in France, Italy, Germany and the United States. The book appeared at a critical moment for science. The disciplines were beginning THOMAS PHILLIPS/ to define their territories and societies were starting to coalesce, including the Geo- logical Society in 1807 and the Zoological Society of London in 1826. For Whewell, who scrutinized Somerville’s offering in depth in the Quarterly Review of March 1834, the work was a “masterly” survey that performed the crucial task of intellec- tual unification at a moment when science threatened to become like “a great empire falling to pieces”. Somerville, the daughter of admiral William Fairfax, grew up near Scotland’s Firth of Forth wandering the seashore, col- lecting shells and studying seabirds. Her father described her as a savage. At 15 she saw a mysterious reference to algebra in a women’s fashion magazine, and began to devour the theorems of Euclid and Newton. She would lie in bed at night, lis- tening to the sea and solving equations in her head. She was launched into Edinburgh society at 18, a notable beauty; to her parents’ Mary Somerville helped to unify science intellectually at a time of specialization. dismay she continued her study of maths, as well as painting and the piano, describ- ing herself as “intensely ambitious to excel in something, for I felt in my own breast that IN RETROSPECT women were capable of taking a higher place in creation than that assigned to them in my early days”. A disastrous first marriage to glamorous naval attaché Samuel Greig was On the Connexion of cut short by his early death in 1807. In 1812 she met and married her soul- mate and cousin, the scientifically minded, the Physical Sciences globe-trotting physician William Somer- ville. Moving to London in 1816, and now the parents of four children, the cou- Richard Holmes finds Mary Somerville’s breakthrough ple entertained leading scientists such as science best-seller thrillingly fresh, 180 years on. William Herschel, Michael Faraday, Charles Babbage and Charles Lyell. In 1830, at the invitation of the Society for the Diffusion ess than two centuries ago, popu- The remarkable writer who first achieved of Useful Knowledge, she translated French lar science barely existed. In 1830, that “connected view” and arguably astronomer Pierre-Simon Laplace’s highly astronomer John Herschel wrote launched popular science writing was a technical The Mechanism of the Heavens. In Lto natural philosopher William Whewell self-taught Scottish mathematician, Mary a parliamentary debate on scientific educa- about the urgent need for “digests of what Fairfax Somerville (1780–1872). Her book, tion, she was referred to as “one of the only is actually known in each particular branch On the Connexion of the Physical Sciences, six persons in England who understands of science … to give a connected view of published by John Murray in 1834 along- Laplace”. what has been done, and what remains to side works by Walter Scott, Lord Byron Somerville began writing On the Con- be accomplished”. and Jane Austen, contains no equations, nexion of the Physical Sciences in 1832,

during a long visit to Paris. She effectively carrier-pigeon to his home ... or of those (pictured), the geographical explorations became an expert reporter on the latest in the antennae of insects which warn of Lyell and Humboldt, and the teams of developments in European science. Tak- them of the approach of danger”. She also European astronomers who observed the ing full advantage of social networking, she mused about climate change, the cause of return of Halley’s comet, among other feats. contacted Laplace’s influential widow and earthquakes and the existence of planets On the Connexion of the Physical dined with the physicists François Arago, beyond Uranus. Sciences was widely praised by journal- Jean-Baptiste Biot and Joseph- ists and scientists in Britain Louis Gay-Lussac. She had and abroad; both Arago and privileged status at sites from Humboldt deeply admired the Paris Observatory to the it. The popular, large-cir- National Museum of Natural culation journal Mechanics’ History, and in the laborato- Magazine urged its audience: ries of electrical-theory pio- “read it! read it!” Somerville neers André-Marie Ampère dined at the male stronghold and Antoine César Becquerel. of the University of Cam- In contrast to the vague bridge, invited by its science speculations of eighteenth- professors; received honor- century natural philosophy, ary membership of the Royal her 500-page book covers a Astronomical Society among OXFORD SCIENCE ARCHIVE/PRINT COLLECTOR/GETTY OXFORD tight field of hard sciences — others; and, although barred astronomy, physics, chemis- from the Royal Society, is try, geography, meteorology commemorated there in a and electromagnetism. Its formidable marble bust. groundbreaking style, clear Such was her celebrity that and logical, occasionally she wrote, “I am a kind of tame opens out into passages of Lioness at present.” Her friend sublime perspective, such as the novelist Maria Edgeworth, the description of universal however, noted that “while her gravity as a force equally pre- head is up among the stars, her sent “in the descent of a rain feet are firm upon the earth”. drop as in the falls of Niagara; Somerville, privately unor- in the weight of the air, as in thodox and witty, sceptical the periods of the moon”. but still believing in a creator, Somerville ranges over sub- lived up to that estimation jects from stellar parallax to throughout her long life. She terrestrial magnetism, from supported women’s suffrage comets to giant seaweed. (her signature was the first on Her handling of acoustics philosopher John Stuart Mill’s is characteristically brilliant, petition to Parliament); cam- based on the observations paigned against vivisection, of John Herschel, Arago and and against slavery in America; naturalist Alexander von and believed in Darwinian Humboldt. Comparing the French scientists making high-altitude measurements in 1804. evolution. propagation of sound to “a Like the great poets of her field of corn agitated by a gust of wind”, The most original sections deal with elec- era, Somerville brought a new vision into the she goes on to describe phenomena from tricity and the new science of electromag- world, and one that a broad, educated pub- birdsong to thunder. She also suggests a netism. Somerville thrillingly describes lic could grasp. Seven years after her death, connection between waves propagated in Faraday’s latest work with the horseshoe a new women’s college at the University of water, the atmosphere and sunlight, writ- magnetic generator, establishing that mag- Oxford was named in her honour. ing: “Any one who has observed the reflec- netism and electricity must have complex Looking back almost 40 years after the tion of the waves from a wall on the side of links in what he was beginning to define publication of her magnum opus, Max- a river ... after the passage of a steam-boat, as ‘fields’. These sections clearly predict the well reflected: “It was one of those sug- will have a perfect idea of the reflection of connection between all electromagnetic gestive books which put into definitive, sound and of light.” phenomena, established in four equations intelligible and communicative form the Her exploration of the solar spectrum a generation later by physicist James Clerk guiding ideas that are already working contains one of the earliest descriptions Maxwell (see nature.com/maxwell). in the minds of men of science”. In fact, (derived from work by William Herschel, Somerville’s work contextualized the the book prompted the creation of a new chemist William Hyde Wollaston and sciences as an ongoing global project. The professional concept, and a new umbrella physicist Johann Wilhelm Ritter) of infra- book emphasized, in a wholly new way, word to define it, coined by Whewell in his red and ultraviolet rays at the extreme the communal nature of science as shared review of 1834: “scientist”. ■ ends of the known light spectrum, “too discovery, referring extensive in their undulations to affect our NATURE.COM to John Franklin’s Richard Holmes is the author of The Age optic nerves”. She speculates that such rays For Richard Arctic expeditions, of Wonder, which won the 2009 Royal might have many possible functions in the Holmes on science the high-altitude Society Prize for Science Books, and Falling animal kingdom: “We are altogether igno- biography, see: balloon flights of Upwards: How We Took to the Air. rant of the perceptions which direct the go.nature.com/9atgoi Biot and Gay-Lussac e-mail: [email protected]