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The Poet of Chemistry

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.”

  1. 9

    A poignant illustration of the gap between Davy’s ideal self, and his actual self is to be found in his “Eagle” poem, in which the old eagles teach the younger ones to fly, and indeed to outfly them:

    So should I wish the light to rise,

    Instructing younger spirits to aspire,

    Where I could never reach amidst

    the skies…

    This poem was written in 1820, at a time when Faraday was spreading his wings, and making his own revolutionary discoveries of electromagnetic induction—the first of the discoveries which were ultimately to eclipse all of Davy’s.

  2. 10

    Davy had been reluctant, up to this point, to believe that diamond and charcoal were, in fact, one and the same element; he felt this was “against the analogies of Nature.” It was perhaps his weakness, as well as his strength, that he sometimes thought to classify the chemical world by concrete qualities, not formal properties. For the most part—as with the alkali metals and the halogens—concrete qualities correspond to formal properties; it is rather rare for elements to have a number of quite different physical forms. Davy wondered whether these might represent different forms of “aggregation” of the atoms themselves, but it was only with the rise of structural chemistry, much later, that this could be defined (the hardness of diamond, it was then shown, was due to the tetrahedral form of its atomic lattices, the softness and greasiness of graphite due to the packing of its hexagonal lattices in parallel sheets). Very recently (1993) an exquisitely structured compound created at the Royal Institution has been called DAF-1 (Davy-Faraday-1), in remembrance of Davy and Faraday’s first speculations on molecular architecture.

  3. 11

    Davy went on with his investigations of flame, and, a year after the safety-lamp, published “Some Philosophical Researches on Flame.” More than forty years later, Faraday would return to the subject, in his famous 1861 Royal Institution lectures on “The Chemical History of a Candle.”

  4. 12

    This was my own introduction to Humphry Davy. I was taken, when very young, to the Science Museum in London by my mother, up to the top floor where there was a very realistic simulacrum of a nineteenth-century coal mine. She first showed me the Davy lamp, and explained how it made it safe to work in coal mines; and then she showed me another safety lamp, the Landau lamp. “My father, your grandfather, invented this,” she said, “when he was a young man in 1869. It was even safer than the original design, and came to replace the Davy lamp.” I felt a thrill of identification, and another thrill at the thought of his predecessor, Humphry Davy. I had then the sense—childish, but very vivid—of science as a completely human business: influences, conversations, across the ages.

  5. 13

    Although Davy found this first example, the general principle of catalysis, and the coining of the term, were only put forward in 1835 by Berzelius.

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