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Uncle Tungsten
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p117 Born in 1778, Davy grew up at the beginning of Lavoisier’s revolution. It was an age of discovery, the coming-of-age of chemistry -- a time, too, when great theoretical clarifications were emerging. Davy, an artisan’s son, was apprenticed to a local apothecary-surgeon in Penzance, but soon aspired to something larger... He read and mastered Lavoisier’s Elements of Chemistry -- a remarkable achievement for an eighteen-year-old with little formal education...
p118 Lavoisier had left a ghost of phlogiston in his conception of heat or “caloric” as an element, and in his first, seminal experiment, Davy melted ice by friction, thus showing that heat was motion, a form of energy, and not a material substance, as Lavoisier had thought... He set forth the results of his experiments in a long “Essay on Heat and Light,” [1799] a critique of Lavoisier as well as a vision of a new chemistry that he hoped to found, one finally purged of all the remnants of alchemy and metaphysics.
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p119 In 1800 Davy read Alessandro Volta’s paper describing the first battery, his “pile” -- a sandwich of two different metals with brine-dampened cardboard in between -- which generated a steady electric current... no sustained electrical current was obtainable until now. 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 now saw as his life’s work.
He persuaded [Thomas] Beddoes to build a massive electric battery... and started his first experiments with it a few months after Volta’s paper. He suspected almost at once that the electric current was generated by chemical changes in the metal plates and wondered if the reverse was also true -- whether one might induce chemical changes by the passage of an electric current.
So exciting... we’re finally closer to electrons!
Water could be created (as Cavendish had shown) by sparking hydrogen and oxygen together. Could one now, with the new power of electric current., do the opposite? In his very first electrochemical experiment, passing an electric current through water (he had to add a little acid to render it conducting), Davy showed that it could be decomposed into its constituent elements, hydrogen appearing at one pole or electrode of the battery, and oxygen at the other -- though it was only several years later that he was able to show that they appeared in fixed and exact proportions.
p120 [footnote - Cavendish sounds like another person on the Asperger's spectrum. Sacks thinks this too.]
With his battery, Davy found, he could not only electrolyze water, but heat metallic wires: a platinum wire, for example, could be heated to incandescence; and if the current was passed into rods of carbon, and these were then separated by a short distance, a dazzling electric “arc” would leap out and bridge the gap... Thus, almost casually, Davy hit upon what were to become two major forms of electrical illumination, incandescence and arc lighting -- though he did not develop these, but went on to other things.
p122 [Lavoisier had suspected that the “alkaline earths” contained undiscovered elements and Davy suspected the same of the alkalis (soda and potash)] ....Davy attacked the alkalis [with electricity], and early in 1807 performed the famous experiments that isolated metallic potassium and sodium by electric current...
One of my greatest delights was to repeat Davy’s original experiments in my own lab... I diced a little pellet of... [metallic potassium] (it cut like butter, and the surface glistened a brilliant silver-white -- but only for an instant; it tarnished at once). I lowered it gently into a trough full of water and stood back -- hardly fast enough, for the potassium caught fire instantly, melted, and as a frenzied molten blob rushed round and round in the trough, with a violet flame above it, spitting and crackling loudly as it threw off incandescent fragments in all directions. In a few seconds the little globule had burned itself out... But now the water felt warm, and soapy; it had become a solution of caustic potash, and being alkaline, it turned a piece of litmus paper blue.
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p123 Before Humphry Davy’s discovery of sodium and potassium, metals were thought of as hard and dense and infusible, and here were ones as soft as butter, lighter than water, very easily melted, and with a chemical violence, an avidity to combine beyond anything ever seen...
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p124 After his success in isolating the first alkali metals, Davy turned to the alkaline earths and electrolyzed these, and within a few weeks he had isolated four more metallic elements -- calcium, magnesium, strontium, and barium -- all highly reactive and all able to burn, like alkali metals, with brilliantly colored flames. These clearly formed another natural group.
I believe this is, because of his dependence on that room sized battery, the first instance in history of “big science.” (Yes, I know I'm using this term incorrectly. It is supposed to be science that requires teams rather than individuals; but I have in mind the need for expensive apparatus. Just as the Large Hadron Collider was required to make certain recent discoveries, the biggest battery ever created was necessary to discover these elements.) Goethe must have been both excited, as a scientist, and apprehensive at this sudden churning out of new, violent elements.
Pure alkali metals do not exist in nature; nor do the elemental alkaline earth metals -- they are too reactive and instantly combine with other elements. What one finds instead are simple or complex salts of these elements. While salts tend to be nonconducting when crystalline, they can conduct an electric current well if dissolved in water or melted; and will indeed be decomposed by an electric current, yielding the metallic component of the salt (e.g., sodium) at one pole, and the nonmetallic element (e.g., chlorine) at the other. This implied to Davy that the elements were contained in the salt as charged particles -- why else should they be attracted to the electrodes? Why did sodium always go to one electrode and chlorine to the other? His pupil, Michael Faraday, was later to call these charged particles of an element “ions,” and further distinguished the positive and negative ones as “cations” and “anions.” [Finally!] Sodium, in its charged state, was a strong cation, and chlorine, in its charged state, one of the strongest anions.
p125 For Davy, electrolysis was a revelation that matter itself was not something inert, held together by “gravity,” as Newton had thought, but was charged and held together by electrical forces. Chemical affinity and electrical force, he now speculated, were one and the same. For Newton and Boyle there had been only one force, universal gravity, holding not only the stars and planets together, but the very atoms of which they were composed. Now, for Davy, there was a second cosmic force, a force no less potent than gravity, but operating at the tiny distances between atoms, in the invisible, almost unimaginable, world of chemical atoms. Gravity, he felt, might be the secret of mass, but electricity was the secret of matter.
Doesn’t this sound like Quantum Mechanics in the following century? Substitute Einstein for Newton, and the Strong Force for gravity.
Just as Lavoisier’s new terminology gave scientists a way to categorize and understand substances, Davy and Faraday gave scientists an inkling of what was actually happening. Going back to Faust again, tossing aside the veil of alchemical language and the fog of metaphysical confusion about what was involved in chemical reactions, must have been as confusing and disconcerting for a fully initiated alchemist like Faust as it was enlightening. And seeing the raw -- demonic -- power of some of these reactions, like the one above with potassium, must have been frightening.
(Footnote: Mary Shelley, as a child, was enthralled by Davy’s inaugural lecture at the Royal Institution, and years later, in Frankenstein, she was to model Professor Waldman’s lecture on chemistry rather closely on some of Davy’s words when, speaking of galvanic electricity, he 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.”)
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p126 There was an extraordinary appetite for science, especially chemistry, in these early, palmy days of the Industrial Revolution; it seemed a new and powerful (and not irreverent) way not only of understanding the world but of moving it to a better state. Davy himself seemed to embody this new optimism, to be at the crest of a vast wave of scientific and technological power, a power that promised, or threatened, to transform the world...
Sounds Faustian, in Goethe’s sense, to me. And, with Frankenstein and that demonstration with potassium and water in mind, it's worth remembering the essential role potassium plays in our bodies.
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p130 In a further discovery, Davy found that if a platinum wire was put in an explosive mixture, it would become red-hot and glow. He had discovered the miracle of catalysis: how certain substances, such as the platinum metals, might induce a continuing chemical reaction on their surfaces, without being themselves consumed... But... it was Davy’s personality that appealed to me... filled with the exuberance and enthusiasm of a boy, with a wonderful adventurousness and sometimes dangerous impulsiveness -- he was always at the point of going too far -- and it was this which captured my imagination above all.
That ending about Davy is very faustian.
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