by Oliver Sacks
He persuaded Beddoes to build a large electric battery modeled after Volta’s, 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: could one induce chemical changes by the passage of an electric current? He made ingenious and radical modifications to the battery, and he was the first to make use of the enormous new power available to devise a new form of illumination, the carbon arc lamp.
These brilliant advances excited attention in the capital, and in that same year Davy was invited to the newly founded Royal Institution in London. 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 the 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.
Davy’s inaugural lecture enthralled many, including Mary Shelley. Years later, in Frankenstein, she was to model Professor Waldman’s lecture on chemistry rather closely on some of Davy’s words. (Specifically, when, speaking of galvanic electricity, Davy had said, “A new influence has been discovered, which has enabled man to produce from combinations of dead matter effects which were formerly occasioned only by animal organs.”) And Coleridge, the greatest talker of his age, always came to Davy’s lectures, not only to fill his chemical notebooks but, as he said, “to renew my stock of metaphors.”*3
There was an extraordinary appetite for science, especially chemistry, 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.
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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).
By 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 he began experimenting with the electrolysis of water, using an electric current to split it into its component elements of hydrogen and oxygen and showing that these combined in exact proportions.
The following year he performed the famous experiments that isolated metallic potassium and sodium by electric current. When the current flowed, Davy wrote, “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 two new elements, potassium and sodium. “The globules often burnt at the moment of their formation,” he observed, “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.” When this occurred, Davy, his cousin Edmund records, danced with joy around the lab.*4
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 in the air, 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 one he would certainly have appreciated. I so strongly identified with Davy’s original experiments that I could almost imagine I was discovering these elements myself.
Davy turned to the alkaline earths next, and within a few weeks had isolated their metallic elements, too—calcium, magnesium, strontium, and barium. These were 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 elements in a single year was not enough, Davy isolated yet another element, boron, the following year.
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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 salts—sodium chloride (common salt), for example—compounds that 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 as its electrically charged particles (electropositive sodium, electronegative chloride, in this case) are attracted towards either electrode. (Faraday later named these particles “ions.”)
For Davy, electrolysis was not only “a new path to discovery” that incited him to request ever larger and more powerful batteries for his use. It was also a revelation that matter itself was not something inert, as Newton and others had thought, 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, but they were assumed to be gravitational. Davy could now envisage another universal force, electrical in nature, holding together the very molecules of matter itself. Beyond this, he 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 he was able to show that it was an element. He named it chlorine, in view of its color (from the Greek chloros, greenish yellow). He realized that it was not only a new element but a representative of a whole new chemical family—a family of elements like the alkali metals, too active to exist in nature. Davy felt sure there must be heavier and lighter analogues of chlorine, members of the same family.
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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.
If he enjoyed the highest esteem from his colleagues, winning many scientific honors, he enjoyed an equal fame with the educated public through his popularizations of science. He loved to conduct experiments in public, and his famous lecture-demonstrations were exciting, eloquent, highly dramatic, and sometimes literally explosive. Davy seemed 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 scientist to be so elevated since Newton in 1705.*5
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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 was
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 brilliantly 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. Davy was initially a generous and supportive “father” but later, with Faraday’s increasing intellectual independence, became an oppressive and perhaps envious one.
Faraday, at first wholly admiring of the older man, grew increasingly resentful and also felt a moralistic contempt for Davy’s worldliness. An adherent of a fundamentalist religious sect, he disapproved of all titles, honors, and offices, and resolutely refused them himself in later life. And yet at a deeper level there was between the two men an affection and an intellectual intimacy that never fully deserted them. Both men being shy and somewhat formal in utterance, it is impossible to do more than guess at the inner history of their relationship. But the creative encounter between these two minds of the highest caliber in a sustained and intense relationship was of the greatest importance to both and, indeed, to the history of science.
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DAVY HAD STRONG AMBITIONS for social status and prestige and power, and three days after he was knighted, he married Jane Apreece, a well-connected, bluestocking heiress and a cousin of Sir Walter Scott. Lady Davy (as Sir Humphry always referred to her) was a brilliantly articulate woman who had had a salon in Edinburgh, but like Davy, she was used to independence and adulation; neither was suited to domestic life. The marriage was not only unhappy but destructive of Davy’s dedication to science. More and more of his energy was devoted to hobnobbing with and emulating the aristocrats (“he dearly loved a Lord,” Knight remarks) and trying to be one 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 he experimented with the first “high” explosive, nitrogen trichloride, which has cost many people fingers and eyes. He 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 was bizarre and comic at the same time. Davy brought along a good deal of chemical apparatus and various materials: “an air pump, 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. He also brought along his young research assistant, Faraday (who was treated like a servant by Lady Davy and soon came to hate her).
In Paris, Davy had a visit from Ampère 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 sensed that this might be an analogue of chlorine and soon confirmed that it was a new element (“a new species of matter,” as he wrote in his report to the Royal Society), to which he gave another chromatic name: iodine, from the Greek ioeides, violet-colored.
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;*6 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, where Davy took on the grandest practical challenge of his lifetime.
The Industrial Revolution, now warming up, devoured ever huger amounts of coal; coal mines were dug deeper, deep enough 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 experimented with many different designs for his lamp, and in so doing discovered a number of new principles. He found that the use of narrow metal tubes, in airtight lanterns, prevented the propagation of explosions. He then experimented with wire gauzes, and found that flames could not pass these.*7 Using tubes and gauzes, the perfected Davy lamps, tested in 1816, not only proved safe but also, by the appearance of the flame, were reliable indicators of the presence of fire-damp.*8
Davy never sought compensation or 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.)
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.
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THERE WAS A VISIONARY, mystical dimension to Davy, 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 ways), hidden behind the dazzle of his practical achievements.
Davy took great pains to be an empiricist, but 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. Davy had been fascinated by idealistic philosophy as a young man, benefiting from Coleridge’s passionate translations of Friedrich Schelling, and his own work 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.
For Newton, space was a mere medium, structureless, in which motion occurred, while forces such as gravity were quite mysterious, seeming to exemplify “action at a distance.” Only with Faraday came the notion that forces have structure, that magnets or current-bearing wires create a charged field. But 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. One wonders what passed between these two visionary geniuses, Faraday and Davy, when—greatly excited by the work of Ørsted, Ampère, and others—they thought together on the newly discovered phenomena of electromagnetism. It is t
antalizing to think of Davy as a junctional figure between the idealistic universes of Leibniz and Schelling and the modern universes of Faraday, Clerk Maxwell, and Einstein.
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IN 1820, 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, had been the aristocratic Sir Joseph Banks. No office in science carried more power or prestige, but none carried heavier diplomatic or administrative burdens. It has been estimated that Banks wrote more than fifty thousand letters, and perhaps as many as a hundred thousand, during his tenure. This crushing burden now fell on Davy.
Even more serious were the repercussions of Davy’s efforts to reform the Royal Society, which, by the 1820s, had to some extent become a society of well-born, sometimes highly gifted men who had not actually 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 diminish unproductive patronage and 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 that hangs in the Royal Institution. Once the most popular scientist in England, he became, in David 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 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 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 Berzelius, who was now bringing all of inorganic chemistry under his sway, dismissed Davy’s life work as no more than “brilliant fragments.”
