The Poet of Chemistry

1.

On April 6, 1804, Coleridge boarded the Speedwell and sailed into exile. A grim apprehension gripped him and most of his friends. “Suppose,” writes Richard Holmes, in the tantalizing postscript which ends the first volume of his biography, “Coleridge had indeed died, as he and his friends clearly expected he would, aged thirty-one, somewhere in the Mediterranean in 1804?…Suppose his life had never actually had a part two? How would his reputation now stand?…Had Coleridge died young; had he always remained as that youthful, archetypal figure on the ship sailing south, we might be tempted to think of him, paradoxically, as already greater than the man he eventually became.” But Coleridge was to live another thirty-two years; his giant, complex future still lay before him.

A similar thought is expressed by David Knight at the beginning of his biography of Humphry Davy:

Davy died in 1829 when he was fifty; had he died ten years earlier we would have got from contemporaries a very different, and much more favourable, view of him.

Humphry Davy and Coleridge, in their youth, were very close friends; indeed, when Coleridge set sail in 1804 it was Davy’s farewell letter that Coleridge prized above all:

In whatever part of the World you are, you will often live with me, not as a fleeting idea, but as a recollection possessed of creative energy, as an Imagination winged with fire inspiriting and rejoicing. You must not live much longer without giving to all men the proof of power, which those who know you feel in admiration. Perhaps at a distance from the applauding and censuring murmurs of the world, you will be best able to execute those great works which are justly expected from you; you are to be the historian of the Philosophy of feeling.—Do not in any way dissipate your noble nature. Do not give up your birth-right.

Humphry Davy was all of twenty-five when he wrote this, and already recognized as one of the greatest scientists of his day. The youthful Davy recognized, it is clear, some of his friend’s frailties as he admonished him not to “dissipate your noble nature.” But such a dissipation, many of his contemporaries must have thought, was precisely what, in later life, Davy was guilty of himself. It is on this grim note that David Knight opens his fascinating, immensely sympathetic biography. “It is sobering,” Knight writes, “to contemplate the transition from the delightful young man in Penzance and then Clifton, where he be-friended Southey, Coleridge and Wordsworth, to the grumpy and isolated exile in his last years, admired but friendless, frustrated when not sozzled with opium.”

It happened that I was thinking of Humphry Davy when I saw a notice of this biography, and immediately sent for it. I had been in a nostalgic mood myself, recalling my own boyhood—my twelve-year-old self most romantically and deeply in love—more deeply, perhaps, than ever again—with sodium and potassium and chlorine and bromine; in love with a magical shop in whose dark interior I could purchase chemicals for my lab; with the heavy, encyclopedic volumes of Mellor (and where I could decipher them, Gmelin); with London’s Science Museum in South Kensington, where the history of chemistry, especially its beginnings in the late eighteenth and early nineteenth centuries, was laid out; in love, perhaps most of all, with the Royal Institution, much of which still looked and smelled exactly as it must have done when the young Humphry Davy worked there, and where one could browse among and ponder his actual notebooks, manuscripts, lab notes, and letters.

Humphry Davy was for me—as for most boys at that time with a chemistry set or a lab—a beloved hero; a boy himself in the boyhood of chemistry; an intensely appealing figure, as fresh and alive after a hundred years in his way as anyone we knew. Young lovers of science, especially of chemistry, in my generation knew all about Davy’s experiments—from nitrous oxide (which he discovered, described, and became slightly addicted to as a teen-ager); to his often reckless experiments with alkali metals, electric batteries, electric fish, explosives. We imagined him as a Byronic young man with wide-set, dreaming eyes looking much as he does on the cover of Knight’s book; we never thought of him as old.

He is, as Knight remarks, a wonderful subject for a biographer, and there have been many biographies of Davy in the last century and a half, from the Life published by J. Paris in 1831 and Memoirs published by his brother, John Davy, in 1838, to the present day. Knight refers to all of these in detail, but believes that whatever their value as histories of chemistry, or of ideas, they do not do justice to Humphry Davy as a man. Knight himself, trained as a chemist, professor of the history and philosophy of science at Durham, and former editor of the British Journal for the History of Science, as well as author of a major book on the nineteenth-century world view, has every qualification to produce a grand and scholarly work on Davy; but it is the special virtue and delight of his book that it is not merely scholarly but full of human insight and sympathy too.¹

Davy was born in 1778 in Penzance, the eldest of five children, to an engraver and woodcarver. He went to the local grammar school and enjoyed its freedom. “I consider it fortunate that I was left much to myself as a child, and put upon no particular plan of study.” He left school at sixteen, and was apprenticed to a local apothecary-surgeon, but he was bored by this, and aspired to something larger. Chemistry, above all, started to attract him: he read and mastered Lavoisier’s great Elements of Chemistry (1789), a remarkable achievement for an eighteen-year-old with little formal education. Grand visions started revolving in his mind: Could he be the new Lavoisier, perhaps the new Newton? One of his notebooks from this time was labeled “Newton and Davy.”

And yet, in a way, it was less with Newton than with Newton’s friend and contemporary Robert Boyle that Davy’s affinities lay. For while Newton had founded a new physics, Boyle had founded the equally new science of chemistry and disentangled it from its alchemical precursors. It was Boyle, in his 1661 Sceptical Chymist, who threw out the metaphysical four elements of the ancients, and redefined “elements” as simple, pure, undecomposable bodies made up of “corpuscles” of a particular kind. It was Boyle who saw the main business of chemistry as analysis (and who introduced the word “analysis” in a chemical context), breaking down complex substances into their constituent elements and seeing how and why these could combine. Boyle’s enterprise gathered force in the succeeding century, when more than a dozen new elements were isolated in quick succession.

But a peculiar confusion attended the isolation of these elements. The Swedish chemist Karl Wilhelm Scheele, obtaining a heavy greenish vapor from hydrochloric acid in 1774, failed to realize that it was an element, and saw it instead as “dephlogisticated muriatic acid,” while Joseph Priestley, isolating oxygen the same year, called it “dephlogisticated air.” These misinterpretations arose from a strange, half-mystical theory which had dominated chemistry throughout the eighteenth century, and, in many ways, prevented its advance. “Phlogiston” was, it was believed, an immaterial substance given off by burning bodies; it was the material of heat. If sulphur was burnt, it gave off phlogiston (manifest as heat and light), with little residue; thus it consisted mainly of phlogiston. If a metal was heated and a residue of calx (or oxide) was left behind, therefore, the theory went, the metal consisted of calx and phlogiston.

Lavoisier, whose great Elements was published when Davy was eleven, overthrew the phlogiston theory, and showed that combustion did not involve the loss of a mysterious “phlogiston,” but resulted from the combination of what was burned with oxygen from the atmosphere (or oxidation). Lavoisier was the first to publish a scientific table of the elements. But he had a lingering belief in the old notions of phlogiston and caloric, so that caloric, the substance of heat, was included among his elements, while oxygen gas was seen as a compound of oxygen and caloric.

Lavoisier’s work stimulated Davy’s first, seminal experiment, at the age of eighteen, when he melted ice by friction, thus showing that heat was motion, a form of energy,² and not a material substance like caloric. “The non-existence of caloric, or the fluid of heat, has been proved,” he exulted. Davy embodied the results of his experiments, and new thoughts, in a long “Essay on Heat and Light,” a critique of Lavoisier and of all chemistry since Boyle as well as a vision of a new chemistry that he hoped to found, one purged of all the metaphysics and phantoms of the old.

News of the young man, of his intellect and perhaps revolutionary new thoughts about matter and energy, reached Thomas Beddoes, then Reader in Chemistry at Oxford (and father of the poet Thomas Lovell Beddoes). Beddoes published Davy’s essay, and invited him to his laboratory—the Pneumatic Institute—in Bristol. Here Davy did his first major work, isolating the oxides of nitrogen and examining their physiological effects. This included a wonderful account of the effects on himself of inhaling the fumes of nitrous oxide—“laughing gas”—which in its psychological perspicacity is reminiscent of William James’s own account of the same experience, a century later.³ It is perhaps the first description of a psychedelic experience in Western literature:

A thrilling extending from the chest to the extremities was almost immediately produced…my visible impressions were dazzling and apparently magnified, I heard distinctly every sound in the room…. As the pleasurable sensations increased, I lost all connection with external things; trains of vivid visible images rapidly passed through my mind and were connected with words in such a manner, as to produce perceptions perfectly novel. I existed in a world of newly connected and newly modified ideas. I theorised; I imagined that I made discoveries.

This important, and delightful, first work was published by Thomas Cottle, also the publisher of Coleridge and Southey. His period at Bristol saw the start of Davy’s close friendship with Coleridge and the Romantic poets. He was writing, and sometimes publishing, a good deal of poetry himself at the time; his notebooks mix details of chemical experiments, poems, and philosophical reflections all together—these did not seem to exist in separate compartments in his mind. Cottle, on meeting him, felt that Davy was a poet, no less than a natural philosopher, and that either, or both, represented his singularity of perception: “It was impossible to doubt, that if he had not shone as a philosopher, he would have become conspicuous as a poet.” This view indeed was shared by all his poetic friends, and indeed he was asked by Wordsworth in 1800 to oversee the publication of the second edition of the Lyrical Ballads.

At this time, there still existed a union of literary and scientific cultures; there was not the dissociation of sensibility that was so soon to come. There was indeed, between Coleridge and Davy, a passionate parallelism, a sense of an almost mystical affinity and rapport. Coleridge planned, at one point, to set up a chemical laboratory with Davy. The poet and the chemist, metaphorically, were fellow warriors, analyzers and explorers of a principle of connectedness of mind and nature. In Coleridge’s words,

Water and flame, the diamond, the charcoal…are convoked and fraternized by the theory of the chemist…. It is the sense of a principle of connection given by the mind, and sanctioned by the correspondency of nature….If in a Shakespeare we find nature idealized into poetry, through the creative power of a profound yet observant meditation, so through the meditative observation of a Davy…we find poetry, as it were, substantiated and realized in nature: yea, nature itself disclosed to us,…as at once the poet and the poem!

Coleridge and Davy seemed to see themselves as twins: Coleridge the chemist of language, Davy the poet of chemistry—both explorers of the divine “I am.”

In the eighteenth century static electricity was known, but no sustained electric current was possible until Alessandro Volta published in 1800 the discovery of his “pile,” a sandwich of two different metals, with brine-dampened cardboard in between, which generated a steady electric current—the first battery. Volta’s paper, Davy was later to write, acted like an alarm bell among the experimenters of Europe, and, for Davy, suddenly gave form to what he would now see as his life’s work. As Knight writes:

The clockwork universe so detested by Romantic thinkers was an obsolete conception; beneath the apparent solidity and stability of matter lay polar forces in equilibrium. Newton had understood gravitation, but the new Newton would come to grips with these new forces and create a dynamic science to replace the mechanical world view.

The key to this, Davy felt, would come through the use of electricity. He persuaded Beddoes to build a large electric battery, and started his first experiments with it in 1800. He suspected almost at once that its current was generated by chemical changes in the metal plates, and wondered if the reverse was also true—that one might induce chemical changes by the passage of an electric current. He started to make ingenious (and radical) modifications of the battery. And he was the first to make use of the enormous new power available to make a new form of illumination, the carbon arc-lamp.

These brilliant advances excited attention in the capital, and in that same year he was invited to the newly founded Royal Institution in London. This opened a new chapter in his life. He had always been eloquent, and a natural storyteller, and now he was to become the most famous and influential lecturer in England, drawing huge crowds that blocked the streets whenever he lectured. His lectures moved from the most intimate details of his experiments—reading them gives a vivid view of work in progress, of the activity of an extraordinary mind—to speculation about the universe and life, delivered in a style and with a richness of language that nobody else could match.⁴ Even Coleridge, the greatest talker of his age, always came to Davy’s lectures, not only to fill his chemical notebooks, but “to renew my stock of metaphors.”⁵

Chemistry was conceived, in Davy’s time, to embrace not only chemical reactions proper, but the study of heat, light, magnetism and electricity, much of what was later to be separated off as “physics” (even at the end of the century, the Curies first regarded radioactivity as a “chemical” property of certain elements). There was an extra-ordinary appetite for science, especially chemistry, at this time, in the early, palmy days of the Industrial Revolution; it seemed a new and powerful (and not irreverent) way not only of understanding the world but moving it to a better state. This double view of science found its perfect exponent in Davy. “In this view,” as he said in his inaugural lecture,

we do not look to distant ages, or amuse ourselves with brilliant but delusive dreams concerning the infinite improveability of man, the annihilation of labour, disease, and even death, but we reason by analogy from simple facts, we consider only a state of human progression arising out of its present condition—we look for a time that we may reasonably expect—for a bright day, of which we already behold the dawn.

In these first years of the Royal Institution, Davy put aside his larger speculations and concentrated on particular practical problems: problems of tanning, and the isolation of tannin (he was the first to find it in tea); and a whole range of agricultural problems—he was the first to recognize the vital role of nitrogen, and the importance of ammonia in fertilizers (his Elements of Agricultural Chemistry was published in 1813). There is no sign that Davy was impatient with such science, or felt himself in any way to be above such humdrum problems. (In this he resembles Pasteur, who did not disdain to work on the practical problems of viniculture, but was led from these to the most general ideas on fermentation and life.)

In 1806, however, established as the most brilliant lecturer and practical chemist in England—and still only twenty-seven—Davy felt he needed to give up his research obligations at the Royal Institution, and return to the fundamental concerns of his Bristol days. He had long wondered whether an electric current could provide a new way of isolating chemical elements, and now, freed from the pressure of other research, he could go back and put this to the test. He began experimenting with the electrolysis of water, using an electric current to split it into its component elements and showing that these combined in exact proportions.

The following year he performed the famous experiments which isolated metallic potassium and sodium by electric current. Knight gives us, in fascinating contrast, Davy’s first, breathless, almost inarticulate account of his discoveries in his lab notebook, and the famous later account known to every schoolboy of my generation: When the current flowed “a most intense light was exhibited at the negative wire, and a column of flame…arose from the point of contact.” This produced shining metallic globules, indistinguishable in appearance from mercury—globules of a new element, metallic potassium. “The globules often burnt at the moment of their formation, and sometimes violently exploded and separated into smaller globules, which flew with great velocity through the air in a state of vivid combustion, producing a beautiful effect of continued jets of fire.”⁶ When this occurred, Davy, his cousin Edmund records, danced with joy around the lab.

My own greatest delight, as a boy, was to repeat Davy’s electrolytic production of sodium and potassium, to see these shining globules catch fire of themselves, burning with a vivid yellow flame or a pale mauve one; and later, to obtain metallic rubidium (which burns with an enchanting ruby-red flame), an element not known to Davy, but which he would certainly have appreciated. I so identified with Davy’s original experiments that I could almost feel I was discovering these elements myself.

“Soda” and “potash,” the alkalis, had been regarded as elements by Lavoisier, as had the alkaline earths—lime, magnesia, strontia, and baryta. Davy next turned to these, and within a few weeks had isolated their metallic elements too—calcium, magnesium, strontium, and barium—highly reactive metals, especially strontium and barium, able to burn, like the alkali metals, with brilliantly colored flames. And if the isolation of six new, unprecedentedly reactive metallic elements in a single year was not enough, Davy isolated yet another element, boron, the following year.

Elemental sodium and potassium do not exist in nature; they are too reactive and will instantly combine with other elements. What one finds, instead, are neutral salts—sodium chloride (common salt), for example—which are chemically inert and electrically neutral. But if one submits these, as Davy did, to a powerful electric current transmitted through two electrodes, the neutral salt can be decomposed, its intensely active and electrically charged particles (electropositive sodium, electronegative chloride, for example) being attracted toward either electrode. Faraday later named these particles “ions.”

For Davy, electrolysis was not only “a new path of discovery,” which incited him to request ever larger and more powerful batteries for his use—the beginnings of “big science,” in 1808. It was also a revelation that matter itself was not something inert, as had been thought by Newton and hitherto, but was charged and held together by electrical forces.

Chemical affinity and electrical force, Davy now realized, determined each other, and were one and the same in the constitution of matter. Boyle and his successors, including Lavoisier, had no clear idea about the fundamental nature of chemical bonds. They were assumed up to Davy’s time to be gravitational; Davy could now envisage another universal force, electrical in nature, holding together the very molecules of matter itself, and beyond this, had a cloudy but intense vision that the entire cosmos was pervaded by electrical forces as well as gravitation.

In 1810, Davy reexamined Scheele’s heavy greenish gas, previously seen by Scheele and Lavoisier as compound in nature, and was able to show that it was an element. He named it, in view of its color (chloros, greenish yellow), chlorine. He now realized that it was not only a new element, but a representative of a new chemical family—a family of elements, like the alkali metals, too active to exist in nature but of the most distinctive kind. Davy felt sure there must be heavier and lighter analogs of chlorine, members of the same family.⁷

These years from 1806 to 1810 were the most creative years of Davy’s life, both in his empirical discoveries and in the profound concepts arising from them. He had discovered eight new elements. He had overturned the last traces of the phlogiston theory and Lavoisier’s notion that atoms were merely metaphysical entities. He had shown the electrical basis of chemical reactivity. He had grounded chemistry, and transformed it, in these five intense years.

Davy’s electrochemical researches, and his vision of the electrochemical structure of matter, made him; for many of his countrymen, “the Newton of chemistry.” If he enjoyed the highest esteem from his colleagues, winning many scientific honors at this time, he enjoyed an equal fame with the educated public through his popularizations of science. He loved to conduct experiments in public, and his famous lectures, or lecture-demonstrations, were exciting, eloquent, highly dramatic, and, sometimes literally, explosive. Davy, moreover, seemed in his own person to be at the crest of a vast new wave of scientific and technological power, a power that promised, or threatened, to transform the world. What honor could the nation bestow on such a man? There seemed only one, though it was almost without precedent. On April 8, 1812, Davy was knighted by the prince regent, the first scientist⁸ to be so elevated since Newton in 1705.

2.

Davy “conducted his research in romantic disorder,” Knight tells us, “and in great bursts of speed after an incubation period.” He worked alone, aided only by a laboratory assistant. The first of these was his younger cousin Edmund Davy; the second was Michael Faraday, whose relationship to Davy was to become an intense and complex one, passionately positive at first, clouded later. Faraday (like Edmund Davy before him) was, as Knight points out, almost a son to Humphry Davy, “a son in science,” as the French chemist Berthollet was to say of his own “son,” Gay-Lussac. Faraday, then in his early twenties, had followed Davy’s lectures raptly, and wooed Davy by presenting him with a brilliant transcribed and annotated version of them.

Davy hesitated before taking Faraday on as his assistant. Faraday was an unknown quantity; he was shy, unworldly, gauche, poorly educated. But he had an intense, precocious love of science, and an extraordinary brain. He was in many ways like Davy himself when he had approached Beddoes. Knight charts the vicissitudes of their relationship: Davy a generous and supportive father at first, and then, with his “son’s” increasing intellectual independence, an oppressive and perhaps envious one.⁹

Faraday himself, at first wholly admiring of the older man, became increasingly resentful later, and additionally felt a moralistic contempt for Davy’s worldliness. An adherent of a fundamentalist religious sect, he disapproved of all titles, honors, offices, and resolutely refused them himself in later life. And yet, as Knight reveals, at a deeper level there was between the two men an affection and an intellectual intimacy which, though compromised after 1820, never deserted them. He does not, however, dwell on what may well have been of the greatest importance to both, and indeed to the history of science, the creative encounter between two minds of the highest caliber in a sustained and intense relation. Both men being shy and somewhat formal in utterance, it may be impossible to do more than guess at the inner history of their relationship.

Three days after he was knighted, Davy married Jane Apreece, a well-connected, bluestocking heiress and a cousin of Sir Walter Scott. He had been solitary up to this point, though he had strong ambitions for social status and prestige and power. The effects of the marriage, Knight indicates, were to be deep ones

He gave up lecturing at the Royal Institution…. He wrote up his work as Elements of Chemical Philosophy…and he published his agricultural lectures in what looks like a farewell to arms

It is difficult to get an impartial account of Lady Davy (as Sir Humphry always referred to her). J.A. Paris’s 1831 biography was largely based on her account, and John Davy wrote his own specifically to rebut it. She was a brilliantly articulate woman who had had a salon in Edinburgh; she and Davy had met socially, admired each other, became friends, and decided to marry. Both, Knight wryly remarks, were used to independence and adulation; neither was suited to domestic life. The marriage was not only unhappy, but also, Knight believes, as has every biographer since John Davy, destructive of Davy’s dedication to science. More and more of his energy was devoted to hobnobbing with the aristocracy—“he dearly loved a Lord,” Knight remarks—emulating them, trying to be one of them himself: a hopeless task in Regency England, where a man’s class was ineluctably ordained by his birth, and neither eminence nor title nor marriage could change this.

The Davys did not immediately go on their honeymoon, but planned instead to spend a year on the Continent together, as soon as Humphry had completed his current researches. He had been working on gunpowder and other explosives, and in October of 1812 was to experiment with the first “high” explosive, nitrogen trichloride, which has cost many people fingers and eyes. Davy discovered several new ways of making the combination of nitrogen and chlorine, and caused a violent explosion on one occasion while he was visiting a friend. He wrote all the details to his admiring brother John:

It must be used with very great caution. It is not safe to experiment upon a globule larger than a pin’s head. I have been severely wounded by a piece scarcely bigger.

Davy himself was partially blinded, and did not recover fully for another four months. We are not told what damage was done to his friend’s house.

The honeymoon, as Knight indicates, was bizarre and comic at the same time. Davy brought along a good deal of chemical apparatus and various materials—“an airpump, an electrical machine, a voltaic battery…a blow-pipe apparatus, a bellows and forge, a mercurial and water gas apparatus, cups and basins of platinum and glass, and the common reagents of chemistry,” to which he added some high explosives, to experiment with; and he also brought along his young research assistant, Faraday (who was treated like a servant by Jane Apreece, and soon came to hate her). In Paris, Davy had a visit from Ampre and Gay-Lussac, who brought with them, for his opinion, a sample of a shiny black substance, with the remarkable property that when heated, it did not melt, but turned at once into a vapor of a deep violet color. Davy, with his enormous feeling for the concrete and his genius for analogy, sensed that this might be an analog of chlorine, and soon confirmed that this was indeed so, that it was a new element (“a new species of matter,” as he wrote in his report to the Royal Society), to which he could again give a chromatic name, iodine (ioides, violet).

From France the wedding party moved by stages to Italy, with experiments along the way: burning a diamond, under controlled conditions, with a giant magnifying glass in Florence;¹⁰ collecting crystals from the rim of Vesuvius; analyzing gas from natural vents in the mountains—it turned out to be, Davy found, identical with marsh gas, or methane; and, for the first time, analyzing samples of paint from old masterworks (“mere atoms,” Davy announced).

During this strange chemical honeymoon-à-trois, traipsing across Europe Davy seemed to revert to an irrepressible, inquisitive, mischievous boy full of ideas and pranks. It was a wonderful induction into the scientific life for Faraday, though Lady Davy, it seems, was indisposed for much of the time. But the holiday, long extended, had to come to an end, and the titled couple returned to London.

Here the grandest practical challenge of Davy’s entire lifetime awaited him. The Industrial Revolution, now warming up, devoured ever huger amounts of coal; coal mines were dug deeper, deep enough now to run into the inflammable and poisonous gases of “fire-damp” (methane) and “choke-damp” (carbon dioxide). A canary, carried down in a cage, could serve as a warning of the presence of asphyxiating choke-damp; but the first indication of fire-damp was, all too often, a fatal explosion. It was desperately important to design a miner’s lamp that could be carried into the lightless depths of the mines without any danger of igniting pockets of fire-damp.

Davy had never disdained practical problems. The current gulf between “pure” and “applied” science did not then exist; he experimented with many different designs for such a lamp, and in so doing typically discovered new principles. He first investigated the conditions under which explosions could be communicated and found that the use of narrow metal tubes, in airtight lanterns, prevented their propagation. He then experimented with wire gauzes, and found that flames could not pass these.¹¹ Using tubes and gauzes, the perfected lamps were tried in 1816, and proved not only safe but also, by the appearance of the flame, reliable indicators of the presence of fire-damp.¹²

Typically, Davy sought no compensation, and never patented his invention of the safety-lamp, but gave it freely to the world. In this he was a contrast to his friend William Hyde Wollaston, who made a huge fortune through his commercial exploitation of palladium and platinum.

A further discovery, an unexpected offshoot of the lamp researches, also dated from this year. Davy found that if a platinum wire were put in an explosive mixture, it would glow but not ignite the mixture. He had discovered the miracle of catalysis: how certain substances may induce a continuing chemical reaction on their surfaces, without themselves being consumed.¹³ This was to become indispensable in thousands of industrial processes.

This was the high point of Davy’s public life, as his electrochemical researches had been the high point of his intellectual life. With the creation of his safety-lamp, and its gift to the nation, public awareness and approbation rose to new heights. In 1818, he was raised to the unprecedented (for a scientist) level of a baronet.

Early in 1820, Oersted, in Denmark, demonstrated that passing a current through a wire could cause the deflection of a compass needle nearby. Suddenly two forces of nature, electricity and magnetism, previously unrelated, now became one. Within a week, in Paris, Ampère had shown that electrifying a wire caused a temporary magnetization and orientation of iron filings in its vicinity. A few weeks later, Arago showed that an electric current could cause a permanent magnetizing of steel needles.

Davy almost simultaneously conducted a similar experiment, specifically showing that needles parallel to the current were temporarily magnetized in alignment with it, and needles transverse to it acquired poles, and were permanently magnetized. Ampère, Arago, and Davy made their discoveries independently, and in ignorance of the others’ parallel work. Ohm and Faraday were soon to work out a theoretical understanding of what was happening, and the practical applications—electromagnets and electric motors—followed within a few years. The swiftness of these discoveries, and of their comprehension and practical exploitation, and the many names associated with them, suggest a collective enterprise; yet every discovery was made independently.

Later that year, Davy was accorded the highest honor in science: the presidency of the Royal Society. Newton had held this position for twenty-four years; and the incumbent before Davy, for forty-two years, was the aristocratic Sir Joseph Banks. No office in science carried more power or prestige; and none carried heavier diplomatic or administrative burdens. It has been estimated, according to Knight, that Banks wrote upward of 50,000 letters, and perhaps as many as 100,000, during his tenure. This crushing burden now fell on Davy.

But this, in a sense, was the least of his problems. Much more serious, and minutely analyzed by Knight, were the repercussions of Davy’s efforts to reform the Royal Society, which, by the 1820s, had to some extent become a society of drones, of well-born, sometimes highly gifted men, who had not, in actuality, done anything much for science. Davy argued, not too tactfully, that the society had been losing its reputation steadily, and that its fellows must prove their worth. His constant, often uncouth, efforts to shake up the society, to promote real work, to diminish unproductive patronage, to shape a society of amateurs and gentlemen into professionals, caused defiance and anger among many of the fellows. Davy increasingly became the object of scorn and hostility, and he who had once been described as “enchanting” in manner reacted to all this with rage, arrogance, and intransigence. One sees the bloated, red-faced rage in the portrait of him from this time, which hangs in the Royal Institution. From having been, in 1816, the most popular scientist in England, he became, in Knight’s words, “one of the most disliked men of science ever.”

These were evil times for Davy. Continually vexed with the trivia of the Royal Society; at bay with most of its fellows; cut off now from Coleridge and other friends with whom in earlier days he had known such openness and happiness; stuck in a loveless, childless marriage; conscious, increasingly, as he moved through his forties, of vague organic symptoms, intimations perhaps of the problems which had brought his father to an early death, Davy had reason to bewail his state, and to look back to the powers of an earlier time. He was too distracted to do any original work, which had always been his chief, and often his only source, of inner peace and stability; worse, he no longer felt himself in the forefront of his subject, perceiving that he was regarded by his contemporaries as obsolete or marginal. The Swedish chemist J. J. Berzelius, who was bringing all of inorganic chemistry under his sway, now dismissed Davy’s life work as no more than “brilliant fragments.”

His sense of loss, of hopeless nostalgia, deepened each year. “Ah!” he was to write in 1828,

could I recover anything like that freshness of mind, which I possessed at twenty-five…what would I not give!…How well I remember that delightful season, when, full of power, I sought for power in others; and power was sympathy, and sympathy power;—when the dead and the unknown, the great of other ages and distant places, were made, by the force of the imagination, my companions and friends.

3.

Why did Davy lose (if lose he did) “that freshness of mind” which had been his at twenty-five? It is sometimes said that physicists and chemists do their best work in their youth, and then “burn out,” but the life of Faraday, creative to the end, gives the lie to this generalization. It seems to me that Davy did not lose his “freshness of mind”—that it was with him to the last, and flashed out, at rare moments, to the end. But there is no doubt that from the time of his marriage and knighthood on, and, above all, from the time of his taking on the presidency of the Royal Society, he was deeply distracted for much of the time, and increasingly nervous and depressed.

One episode, which he would have laughed at in happier days, showed the pass to which he had come. The copper bottoms of Navy vessels were prone to corrosion in seawater, but Davy had found that if copper were in contact with a more electropositive metal, it would be protected from chemical reaction. He suggested attaching plates of iron or zinc to the ships’ hulls. Though this worked well under laboratory conditions, it did not work well at sea, because the new metal plates attracted barnacles. Davy was much ridiculed as a result, Knight tells us, and he took this very hard, becoming so mortified that his friends were alarmed. Yet the principle of “cathodic protection,” as Davy conceived it, was brilliant, and eventually became, after Davy’s death, and well into this century, a standard way of protecting the bottoms of ocean-going vessels.

In 1825 he wrote a poem about death. The following year his mother died. He was singularly attached to her, as Newton had been to his mother, and her death affected him grievously. Later that year, at the age of forty-eight, he suffered, as his father had at the same age, a transient numbness in his hand and arm, and weakness in his leg, soon to be followed by a paralytic stroke. Though he recovered speedily, the gravity of this, and its undeniable import, altered his thinking. He suddenly felt sick of the endless struggles at the Royal Society, the endless obligations of his worldly life: “My health was gone, my ambition satisfied, I was no longer excited by the desire of distinction; what I regarded most tenderly was in the grave.”

Much of Davy’s life, since his marriage and knighthood, had been dominated by social striving and worldly ambition; he wanted to turn now, or return, in what life he had left, to “the great, the good, the fair,” as he had called them in an early poem: to bring all his human experience and his scientific knowledge together in one final synthesis which would give it all sense and meaning. He was to do this in the form of two final, meditative works, Salmonia and Consolations. Unusual in Knight’s book is the concentration given to these books, ignored by most biographers, or passed over in embarrassed silence. Knight feels very differently: “Had [Davy] died in 1827, his life would have lacked the shape that these works give it.”

One of Davy’s recreations, perhaps his only one, throughout his adult life, had been fishing. Otherwise distracted, or pompous, or unapproachable, he would regain all his old friendliness, his real self, when fishing. This was the time when his mind became youthful and fresh once again, and he could delight, as he used to, in the pure play of ideas. Over the years Davy, an expert fisherman, became equally expert in his knowledge of flies and fishes. His Salmonia is at once a natural history, an allegory, a dialogue, a poem; Knight calls it “a fishing book suffused with natural theology.”

After completing the book, Davy set sail for Slovenia, accompanied by his godson John Tobin, the last of his scientific “sons.” Out of England, and its climate, which, Davy felt, “kept the nervous system in a constant state of disturbance,” he might hope to receive, to enjoy, and to communicate, his final thoughts: “I had sought for and found consolation, and partly recovered my health after a dangerous illness…I had found the spirit of my early vision….Nature never deceives us, the tocks, the mountains, the streams, always speak the same language….”

In Consolations, Davy returns to the ancient mode of dialogue, modeled consciously or unconsciously on Plato’s dialogues. But delightfully, between composing these farewell enneads, Humphry the boy would suddenly reappear, and Davy would forget he was dying. He started to experiment with a new plaything, the electric fish Torpedo, seeing whether it could generate enough current to electrolyze water. Davy, so often tormented in his later years, found peace and fulfillment in composing these last works. After his final, mortal stroke, in February 1829, he dictated this letter, his nunc dimittis:

I am dying from a severe attack of palsy, which has seized the whole of the body, with the exception of the intellectual organ…. I bless God that I have been able to finish my intellectual labours.

I could not finish Knight’s book without being profoundly moved. It is a singular experience to think again on a man who was my boyhood hero and ideal, but whom I had scarcely thought about for almost fifty years. If I have one reservation, it is this: although Knight has many fine and careful things to say about Davy’s imagination, I do not think he goes deeply enough. Davy, I believe, was greater and stranger than Knight allows for. There was a visionary, mystical dimension, not evident to his contemporaries save perhaps Coleridge and Faraday (who knew him so well, and who were so great and so strange in their own singular ways), hidden, so to speak, behind the dazzle of his practical achievements. Yet this was something he often condemned in others and in himself. Thus, while he was fascinated by Oersted’s discovery of electromagnetism in 1820, he was dismayed at Oersted’s metaphysical bent of mind and his explicit acceptance of Schelling’s Romantic philosophy. Shelling, in his 1797 Ideas for a Philosophy of Nature, sought to replace the Newtonian world of masses and atoms by a world of dynamics, of forces—“We may say that all particular determinations of matter have their ground in the differing relations to magnetism, electricity, and the chemical process.” This sounds, indeed, rather Davyan, but it represented a pronouncement, an apodictic statement of what Schelling regarded as an absolute or a priori dogma about the nature of the world—an attitude quite alien to inductive science, with its slow, piecemeal discoveries and integrations.¹⁴ Oersted had made a spectacular discovery, it was true—but could he be seen as a proper Baconian scientist?

The same question, indeed, might be asked about Davy himself, for though he was at such pains to be an empiricist and a Baconian, he was also a part of the Romantic movement and its Naturphilosophie, and remained so throughout his life. There is not necessarily any contradiction between a mystical or transcendent philosophy and a rigorously empirical mode of experiment and observation; they can go together, as they certainly did with Newton. And Davy too, in this way, was perhaps much closer to Oersted than he cared to admit. Davy himself had been fascinated by idealistic philosophy as a young man, benefiting from Coleridge’s passionate translations of Schelling; and while he gave up some of its tenets (notions of pure Spirit, for example), his own work, like Oersted’s, served to provide an empirical confirmation of some of Schelling’s notions: that the universe was a dynamic whole, held together by energies of opposite valence, and one in which energy, however transformed, was always conserved.

It seems to me that Davy was close to the concept of “field”—the transcendent and, in a sense, Romantic concept we owe to Faraday. For Newton space was absolute, a mere medium, structureless, in which motion occurred, while forces, such as gravity, were quite mysterious, seeming to exemplify “action at a distance.” With Faraday came the notion that forces have structure, that magnets, or current-bearing wires, create a charged field (and with Einstein, of course, the notion that space itself has structure, and is determined by its gravitational fields). One wonders what passed between these two visionary geniuses, Faraday and Davy, especially in their last time of closeness, when, greatly excited by the work of Oersted, they thought together on the new phenomena of electromagnetism. It is tantalizing to think of Davy as a bridge, a junctional figure, between the idealistic universes of Leibniz and Schelling and the modern universes of Faraday, Clerk Maxwell, and Einstein.

I have said that Humphry Davy was a boyhood hero not only to me, but to virtually everyone interested in chemistry or science in my generation; his experiments were known to us, and often repeated by us. Davy himself had had such ideal companions in his youth; particularly Newton and Lavoisier. Newton, for him, was a sort of god; but Lavoisier was closer, more like a father with whom he could talk, agree, disagree. His own first essay, which Beddoes had published, while taking strong issue with Lavoisier, was in effect a dialogue with him. All of us need such figures, such ego ideals, and need them throughout life.¹⁵

Now I find to my dismay when I speak to my younger scientific friends, that none of them has heard of Davy, and some of them are puzzled when I tell them of my interest. It is difficult for them to imagine what relevance such “old” science can have. Science, it is often said now, is impersonal, consists of “information” and “concepts”; these advance continually, by a process of revision and replacement in which old information, old concepts, become obsolete. The science of the past, in this view, is irrelevant to the present, of interest only to the historian or psychologist.¹⁶

But this is not what I have found in reality: when in 1967 I came to write my first book, Migraine, I was stimulated by the nature of the malady and by encounters with my patients, but equally, and crucially, by an “old” book on the subject, Edward Liveing’s book, written in the 1860s. I took this book out of the rarely entered historical section of the medical school library, and read it, cover to cover, in a sort of rapture. I reread it may times for six months and I got to know Liveing extremely well. His presence, his way of thinking, were continually with me. My prolonged encounter with Liveing was crucial for the generation of my own thoughts and book. It was just such an encounter with Humphry Davy, when I was twelve, that had originally confirmed me on the path to science. How could I believe that the history of science, the past, was irrelevant?

I do not think my experience is unique. Many scientists, no less than poets or artists, have a living relation to the past, not just an abstract sense of history and tradition, but a feeling of companions and predecessors, ancestors with whom they enjoy a sort of implicit dialogue. Science sometimes sees itself as impersonal, as “pure thought,” independent of its historical and human origins. It is often taught as if this were the case. But science is a human enterprise through and through, an organic, evolving, human growth, with sudden spurts and arrests, and strange deviations, too. It grows out of its past, but never outgrows it, any more than we outgrow our own childhood. If Humphry Davy reminded me, enchantingly, of my own boyhood, I think it may enchant others, too—by showing them the freshness, the delight, of a science in its boyhood, and the aspirations and workings of an imagination of genius.

Note: I have been much assisted by discussions with Edward Weinberger, with his vivid sense of the dialogic nature of science, and by helpful criticism from Duncan Dallas and Professor William Brock.