7 ELEMENTAL MATTERSCHEMISTRY
《万物简史英文版》章节: 7 ELEMENTAL MATTERSCHEMISTRY,宠文网网友提供全文无弹窗免费在线阅读。!
Perhaps nothing better typifies the strange and often accidental nature of chemical sciencein its early days than a discovery made by a German named Hennig Brand in 1675. Brandbecame convinced that gold could somehow be distilled from human urine. (The similarity ofcolor seems to have been a factor in his conclusion.) He assembled fifty buckets of humanurine, which he kept for months in his cellar. By various recondite processes, he converted theurine first into a noxious paste and then into a translucent waxy substance. None of it yieldedgold, of course, but a strange and interesting thing did happen. After a time, the substancebegan to glow. Moreover, when exposed to air, it often spontaneously burst into flame.
The commercial potential for the stuff—which soon became known as phosphorus, fromGreek and Latin roots meaning “light bearing”—was not lost on eager businesspeople, but thedifficulties of manufacture made it too costly to exploit. An ounce of phosphorus retailed forsix guineas—perhaps five hundred dollars in today’s money—or more than gold.
At first, soldiers were called on to provide the raw material, but such an arrangement washardly conducive to industrial-scale production. In the 1750s a Swedish chemist named Karl(or Carl) Scheele devised a way to manufacture phosphorus in bulk without the slop or smellof urine. It was largely because of this mastery of phosphorus that Sweden became, andremains, a leading producer of matches.
Scheele was both an extraordinary and extraordinarily luckless fellow. A poor pharmacistwith little in the way of advanced apparatus, he discovered eight elements—chlorine, fluorine,manganese, barium, molybdenum, tungsten, nitrogen, and oxygen—and got credit for none ofthem. In every case, his finds were either overlooked or made it into publication aftersomeone else had made the same discovery independently. He also discovered many usefulcompounds, among them ammonia, glycerin, and tannic acid, and was the first to see thecommercial potential of chlorine as a bleach—all breakthroughs that made other peopleextremely wealthy.
Scheele’s one notable shortcoming was a curious insistence on tasting a little of everythinghe worked with, including such notoriously disagreeable substances as mercury, prussic acid(another of his discoveries), and hydrocyanic acid—a compound so famously poisonous that150 years later Erwin Schr?dinger chose it as his toxin of choice in a famous thoughtexperiment (see page 146). Scheele’s rashness eventually caught up with him. In 1786, agedjust forty-three, he was found dead at his workbench surrounded by an array of toxicchemicals, any one of which could have accounted for the stunned and terminal look on hisface.
Were the world just and Swedish-speaking, Scheele would have enjoyed universal acclaim.
Instead credit has tended to lodge with more celebrated chemists, mostly from the English-speaking world. Scheele discovered oxygen in 1772, but for various heartbreakingly complicated reasons could not get his paper published in a timely manner. Instead credit wentto Joseph Priestley, who discovered the same element independently, but latterly, in thesummer of 1774. Even more remarkable was Scheele’s failure to receive credit for thediscovery of chlorine. Nearly all textbooks still attribute chlorine’s discovery to HumphryDavy, who did indeed find it, but thirty-six years after Scheele had.
Although chemistry had come a long way in the century that separated Newton and Boylefrom Scheele and Priestley and Henry Cavendish, it still had a long way to go. Right up to theclosing years of the eighteenth century (and in Priestley’s case a little beyond) scientistseverywhere searched for, and sometimes believed they had actually found, things that justweren’t there: vitiated airs, dephlogisticated marine acids, phloxes, calxes, terraqueousexhalations, and, above all, phlogiston, the substance that was thought to be the active agentin combustion. Somewhere in all this, it was thought, there also resided a mysterious élanvital, the force that brought inanimate objects to life. No one knew where this ethereal essencelay, but two things seemed probable: that you could enliven it with a jolt of electricity (anotion Mary Shelley exploited to full effect in her novel Frankenstein ) and that it existed insome substances but not others, which is why we ended up with two branches of chemistry:
organic (for those substances that were thought to have it) and inorganic (for those that didnot).
Someone of insight was needed to thrust chemistry into the modern age, and it was theFrench who provided him. His name was Antoine-Laurent Lavoisier. Born in 1743, Lavoisierwas a member of the minor nobility (his father had purchased a title for the family). In 1768,he bought a practicing share in a deeply despised institution called the Ferme Générale (orGeneral Farm), which collected taxes and fees on behalf of the government. AlthoughLavoisier himself was by all accounts mild and fair-minded, the company he worked for wasneither. For one thing, it did not tax the rich but only the poor, and then often arbitrarily. ForLavoisier, the appeal of the institution was that it provided him with the wealth to follow hisprincipal devotion, science. At his peak, his personal earnings reached 150,000 livres a year—perhaps $20 million in today’s money.
Three years after embarking on this lucrative career path, he married the fourteen-year-olddaughter of one of his bosses. The marriage was a meeting of hearts and minds both. MadameLavoisier had an incisive intellect and soon was working productively alongside her husband.
Despite the demands of his job and busy social life, they managed to put in five hours ofscience on most days—two in the early morning and three in the evening—as well as thewhole of Sunday, which they called their jour de bonheur (day of happiness). SomehowLavoisier also found the time to be commissioner of gunpowder, supervise the building of awall around Paris to deter smugglers, help found the metric system, and coauthor thehandbook Méthode de Nomenclature Chimique , which became the bible for agreeing on thenames of the elements.
As a leading member of the Académie Royale des Sciences, he was also required to take aninformed and active interest in whatever was topical—hypnotism, prison reform, therespiration of insects, the water supply of Paris. It was in such a capacity in 1780 thatLavoisier made some dismissive remarks about a new theory of combustion that had beensubmitted to the academy by a hopeful young scientist. The theory was indeed wrong, but thescientist never forgave him. His name was Jean-Paul Marat.
The one thing Lavoisier never did was discover an element. At a time when it seemed as ifalmost anybody with a beaker, a flame, and some interesting powders could discover something new—and when, not incidentally, some two-thirds of the elements were yet to befound—Lavoisier failed to uncover a single one. It certainly wasn’t for want of beakers.
Lavoisier had thirteen thousand of them in what was, to an almost preposterous degree, thefinest private laboratory in existence.
Instead he took the discoveries of others and made sense of them. He threw out phlogistonand mephitic airs. He identified oxygen and hydrogen for what they were and gave them boththeir modern names. In short, he helped to bring rigor, clarity, and method to chemistry.
And his fancy equipment did in fact come in very handy. For years, he and MadameLavoisier occupied themselves with extremely exacting studies requiring the finestmeasurements. They determined, for instance, that a rusting object doesn’t lose weight, aseveryone had long assumed, but gains weight—an extraordinary discovery. Somehow as itrusted the object was attracting elemental particles from the air. It was the first realization thatmatter can be transformed but not eliminated. If you burned this book now, its matter wouldbe changed to ash and smoke, but the net amount of stuff in the universe would be the same.
This became known as the conservation of mass, and it was a revolutionary concept.
Unfortunately, it coincided with another type of revolution—the French one—and for this oneLavoisier was entirely on the wrong side.
Not only was he a member of the hated Ferme Générale, but he had enthusiastically builtthe wall that enclosed Paris—an edifice so loathed that it was the first thing attacked by therebellious citizens. Capitalizing on this, in 1791 Marat, now a leading voice in the NationalAssembly, denounced Lavoisier and suggested that it was well past time for his hanging.
Soon afterward the Ferme Générale was shut down. Not long after this Marat was murderedin his bath by an aggrieved young woman named Charlotte Corday, but by this time it was toolate for Lavoisier.
In 1793, the Reign of Terror, already intense, ratcheted up to a higher gear. In OctoberMarie Antoinette was sent to the guillotine. The following month, as Lavoisier and his wifewere making tardy plans to slip away to Scotland, Lavoisier was arrested. In May he andthirty-one fellow farmers-general were brought before the Revolutionary Tribunal (in acourtroom presided over by a bust of Marat). Eight were granted acquittals, but Lavoisier andthe others were taken directly to the Place de la Revolution (now the Place de la Concorde),site of the busiest of French guillotines. Lavoisier watched his father-in-law beheaded, thenstepped up and accepted his fate. Less than three months later, on July 27, Robespierrehimself was dispatched in the same way and in the same place, and the Reign of Terrorswiftly ended.
A hundred years after his death, a statue of Lavoisier was erected in Paris and muchadmired until someone pointed out that it looked nothing like him. Under questioning thesculptor admitted that he had used the head of the mathematician and philosopher the Marquisde Condorcet—apparently he had a spare—in the hope that no one would notice or, havingnoticed, would care. In the second regard he was correct. The statue of Lavoisier-cum-Condorcet was allowed to remain in place for another half century until the Second WorldWar when, one morning, it was taken away and melted down for scrap.
In the early 1800s there arose in England a fashion for inhaling nitrous oxide, or laughinggas, after it was discovered that its use “was attended by a highly pleasurable thrilling.” For the next half century it would be the drug of choice for young people. One learned body, theAskesian Society, was for a time devoted to little else. Theaters put on “laughing gasevenings” where volunteers could refresh themselves with a robust inhalation and thenentertain the audience with their comical staggerings.
It wasn’t until 1846 that anyone got around to finding a practical use for nitrous oxide, asan anesthetic. Goodness knows how many tens of thousands of people suffered unnecessaryagonies under the surgeon’s knife because no one thought of the gas’s most obvious practicalapplication.
I mention this to make the point that chemistry, having come so far in the eighteenthcentury, rather lost its bearings in the first decades of the nineteenth, in much the way thatgeology would in the early years of the twentieth. Partly it was to do with the limitations ofequipment—there were, for instance, no centrifuges until the second half of the century,severely restricting many kinds of experiments—and partly it was social. Chemistry was,generally speaking, a science for businesspeople, for those who worked with coal and potashand dyes, and not gentlemen, who tended to be drawn to geology, natural history, and physics.
(This was slightly less true in continental Europe than in Britain, but only slightly.) It isperhaps telling that one of the most important observations of the century, Brownian motion,which established the active nature of molecules, was made not by a chemist but by a Scottishbotanist, Robert Brown. (What Brown noticed, in 1827, was that tiny grains of pollensuspended in water remained indefinitely in motion no matter how long he gave them tosettle. The cause of this perpetual motion—namely the actions of invisible molecules—waslong a mystery.)Things might have been worse had it not been for a splendidly improbable character namedCount von Rumford, who, despite the grandeur of his title, began life in Woburn,Massachusetts, in 1753 as plain Benjamin Thompson. Thompson was dashing and ambitious,“handsome in feature and figure,” occasionally courageous and exceedingly bright, butuntroubled by anything so inconveniencing as a scruple. At nineteen he married a rich widowfourteen years his senior, but at the outbreak of revolution in the colonies he unwisely sidedwith the loyalists, for a time spying on their behalf. In the fateful year of 1776, facing arrest“for lukewarmness in the cause of liberty,” he abandoned his wife and child and fled justahead of a mob of anti-Royalists armed with buckets of hot tar, bags of feathers, and anearnest desire to adorn him with both.
He decamped first to England and then to Germany, where he served as a military advisorto the government of Bavaria, so impressing the authorities that in 1791 he was named Countvon Rumford of the Holy Roman Empire. While in Munich, he also designed and laid out thefamous park known as the English Garden.
In between these undertakings, he somehow found time to conduct a good deal of solidscience. He became the world’s foremost authority on thermodynamics and the first toelucidate the principles of the convection of fluids and the circulation of ocean currents. Healso invented several useful objects, including a drip coffeemaker, thermal underwear, and atype of range still known as the Rumford fireplace. In 1805, during a sojourn in France, hewooed and married Madame Lavoisier, widow of Antoine-Laurent. The marriage was not asuccess and they soon parted. Rumford stayed on in France, where he died, universallyesteemed by all but his former wives, in 1814.
But our purpose in mentioning him here is that in 1799, during a comparatively briefinterlude in London, he founded the Royal Institution, yet another of the many learnedsocieties that popped into being all over Britain in the late eighteenth and early nineteenthcenturies. For a time it was almost the only institution of standing to actively promote theyoung science of chemistry, and that was thanks almost entirely to a brilliant young mannamed Humphry Davy, who was appointed the institution’s professor of chemistry shortlyafter its inception and rapidly gained fame as an outstanding lecturer and productiveexperimentalist.
Soon after taking up his position, Davy began to bang out new elements one afteranother—potassium, sodium, magnesium, calcium, strontium, and aluminum or aluminium,depending on which branch of English you favor.
1He discovered so many elements not somuch because he was serially astute as because he developed an ingenious technique ofapplying electricity to a molten substance—electrolysis, as it is known. Altogether hediscovered a dozen elements, a fifth of the known total of his day. Davy might have done farmore, but unfortunately as a young man he developed an abiding attachment to the buoyantpleasures of nitrous oxide. He grew so attached to the gas that he drew on it (literally) three orfour times a day. Eventually, in 1829, it is thought to have killed him.
Fortunately more sober types were at work elsewhere. In 1808, a dour Quaker named JohnDalton became the first person to intimate the nature of an atom (progress that will bediscussed more completely a little further on), and in 1811 an Italian with the splendidlyoperatic name of Lorenzo Romano Amadeo Carlo Avogadro, Count of Quarequa and Cerreto,made a discovery that would prove highly significant in the long term—namely, that twoequal volumes of gases of any type, if kept at the same pressure and temperature, will containidentical numbers of molecules.
Two things were notable about Avogadro’s Principle, as it became known. First, itprovided a basis for more accurately measuring the size and weight of atoms. UsingAvogadro’s mathematics, chemists were eventually able to work out, for instance, that atypical atom had a diameter of 0.00000008 centimeters, which is very little indeed. Andsecond, almost no one knew about Avogadro’s appealingly simple principle for almost fiftyyears.
2Partly this was because Avogadro himself was a retiring fellow—he worked alone,corresponded very little with fellow scientists, published few papers, and attended nomeetings—but also it was because there were no meetings to attend and few chemicaljournals in which to publish. This is a fairly extraordinary fact. The Industrial Revolution was1The confusion over the aluminum/aluminium spelling arose b cause of some uncharacteristic indecisiveness onDavys part. When he first isolated the element in 1808, he called it alumium. For son reason he thought better ofthat and changed it to aluminum four years later. Americans dutifully adopted the new term, but mai Britishusers disliked aluminum, pointing out that it disrupted the -ium pattern established by sodium, calcium, andstrontium, so they added a vowel and syllable.
2The principle led to the much later adoption of Avogadros number, a basic unit of measure in chemistry, whichwas named for Avogadro long after his death. It is the number of molecules found in 2.016 grams of hydrogengas (or an equal volume of any other gas). Its value is placed at 6.0221367 x 1023, which is an enormously largenumber. Chemistry students have long amused themselves by computing just how large a number it is, so I canreport that it is equivalent to the number of popcorn kernels needed to cover the United States to a depth of ninemiles, or cupfuls of water in the Pacific Ocean, or soft drink cans that would, evenly stacked, cover the Earth to adepth of 200 miles. An equivalent number of American pennies would be enough to make every person on Eartha dollar trillionaire. It is a big number.
driven in large part by developments in chemistry, and yet as an organized science chemistrybarely existed for decades.
The Chemical Society of London was not founded until 1841 and didn’t begin to produce aregular journal until 1848, by which time most learned societies in Britain—Geological,Geographical, Zoological, Horticultural, and Linnaean (for naturalists and botanists)—were atleast twenty years old and often much more. The rival Institute of Chemistry didn’t come intobeing until 1877, a year after the founding of the American Chemical Society. Becausechemistry was so slow to get organized, news of Avogadro’s important breakthrough of 1811didn’t begin to become general until the first international chemistry congress, in Karlsruhe,in 1860.
Because chemists for so long worked in isolation, conventions were slow to emerge. Untilwell into the second half of the century, the formula H2O2might mean water to one chemistbut hydrogen peroxide to another. C2H4could signify ethylene or marsh gas. There was hardlya molecule that was uniformly represented everywhere.
Chemists also used a bewildering variety of symbols and abbreviations, often self-invented.
Sweden’s J. J. Berzelius brought a much-needed measure of order to matters by decreeing thatthe elements be abbreviated on the basis of their Greek or Latin names, which is why theabbreviation for iron is Fe (from the Latin ferrum ) and that for silver is Ag (from the Latinargentum ). That so many of the other abbreviations accord with their English names (N fornitrogen, O for Oxygen, H for hydrogen, and so on) reflects English’s Latinate nature, not itsexalted status. To indicate the number of atoms in a molecule, Berzelius employed asuperscript notation, as in H2O. Later, for no special reason, the fashion became to render thenumber as subscript: H2O.
Despite the occasional tidyings-up, chemistry by the second half of the nineteenth centurywas in something of a mess, which is why everybody was so pleased by the rise toprominence in 1869 of an odd and crazed-looking professor at the University of St. Petersburgnamed Dmitri Ivanovich Mendeleyev.
Mendeleyev (also sometimes spelled Mendeleev or Mendeléef) was born in 1834 atTobolsk, in the far west of Siberia, into a well-educated, reasonably prosperous, and verylarge family—so large, in fact, that history has lost track of exactly how many Mendeleyevsthere were: some sources say there were fourteen children, some say seventeen. All agree, atany rate, that Dmitri was the youngest. Luck was not always with the Mendeleyevs. WhenDmitri was small his father, the headmaster of a local school, went blind and his mother hadto go out to work. Clearly an extraordinary woman, she eventually became the manager of asuccessful glass factory. All went well until 1848, when the factory burned down and thefamily was reduced to penury. Determined to get her youngest child an education, theindomitable Mrs. Mendeleyev hitchhiked with young Dmitri four thousand miles to St.
Petersburg—that’s equivalent to traveling from London to Equatorial Guinea—and depositedhim at the Institute of Pedagogy. Worn out by her efforts, she died soon after.
Mendeleyev dutifully completed his studies and eventually landed a position at the localuniversity. There he was a competent but not terribly outstanding chemist, known more forhis wild hair and beard, which he had trimmed just once a year, than for his gifts in thelaboratory.
However, in 1869, at the age of thirty-five, he began to toy with a way to arrange theelements. At the time, elements were normally grouped in two ways—either by atomic weight(using Avogadro’s Principle) or by common properties (whether they were metals or gases,for instance). Mendeleyev’s breakthrough was to see that the two could be combined in asingle table.
As is often the way in science, the principle had actually been anticipated three yearspreviously by an amateur chemist in England named John Newlands. He suggested that whenelements were arranged by weight they appeared to repeat certain properties—in a sense toharmonize—at every eighth place along the scale. Slightly unwisely, for this was an ideawhose time had not quite yet come, Newlands called it the Law of Octaves and likened thearrangement to the octaves on a piano keyboard. Perhaps there was something in Newlands’smanner of presentation, but the idea was considered fundamentally preposterous and widelymocked. At gatherings, droller members of the audience would sometimes ask him if he couldget his elements to play them a little tune. Discouraged, Newlands gave up pushing the ideaand soon dropped from view altogether.
Mendeleyev used a slightly different approach, placing his elements into groups of seven,but employed fundamentally the same principle. Suddenly the idea seemed brilliant andwondrously perceptive. Because the properties repeated themselves periodically, the inventionbecame known as the periodic table.
Mendeleyev was said to have been inspired by the card game known as solitaire in NorthAmerica and patience elsewhere, wherein cards are arranged by suit horizontally and bynumber vertically. Using a broadly similar concept, he arranged the elements in horizontalrows called periods and vertical columns called groups. This instantly showed one set ofrelationships when read up and down and another when read from side to side. Specifically,the vertical columns put together chemicals that have similar properties. Thus copper sits ontop of silver and silver sits on top of gold because of their chemical affinities as metals, whilehelium, neon, and argon are in a column made up of gases. (The actual, formal determinant inthe ordering is something called their electron valences, for which you will have to enroll innight classes if you wish an understanding.) The horizontal rows, meanwhile, arrange thechemicals in ascending order by the number of protons in their nuclei—what is known as theiratomic number.
The structure of atoms and the significance of protons will come in a following chapter, sofor the moment all that is necessary is to appreciate the organizing principle: hydrogen hasjust one proton, and so it has an atomic number of one and comes first on the chart; uraniumhas ninety-two protons, and so it comes near the end and has an atomic number of ninety-two.
In this sense, as Philip Ball has pointed out, chemistry really is just a matter of counting.
(Atomic number, incidentally, is not to be confused with atomic weight, which is the numberof protons plus the number of neutrons in a given element.) There was still a great deal thatwasn’t known or understood. Hydrogen is the most common element in the universe, and yetno one would guess as much for another thirty years. Helium, the second most abundantelement, had only been found the year before—its existence hadn’t even been suspectedbefore that—and then not on Earth but in the Sun, where it was found with a spectroscopeduring a solar eclipse, which is why it honors the Greek sun god Helios. It wouldn’t beisolated until 1895. Even so, thanks to Mendeleyev’s invention, chemistry was now on a firmfooting.
For most of us, the periodic table is a thing of beauty in the abstract, but for chemists itestablished an immediate orderliness and clarity that can hardly be overstated. “Without adoubt, the Periodic Table of the Chemical Elements is the most elegant organizational chartever devised,” wrote Robert E. Krebs in The History and Use of Our Earth’s ChemicalElements, and you can find similar sentiments in virtually every history of chemistry in print.
Today we have “120 or so” known elements—ninety-two naturally occurring ones plus acouple of dozen that have been created in labs. The actual number is slightly contentiousbecause the heavy, synthesized elements exist for only millionths of seconds and chemistssometimes argue over whether they have really been detected or not. In Mendeleyev’s dayjust sixty-three elements were known, but part of his cleverness was to realize that theelements as then known didn’t make a complete picture, that many pieces were missing. Histable predicted, with pleasing accuracy, where new elements would slot in when they werefound.
No one knows, incidentally, how high the number of elements might go, though anythingbeyond 168 as an atomic weight is considered “purely speculative,” but what is certain is thatanything that is found will fit neatly into Mendeleyev’s great scheme.
The nineteenth century held one last great surprise for chemists. It began in 1896 whenHenri Becquerel in Paris carelessly left a packet of uranium salts on a wrapped photographicplate in a drawer. When he took the plate out some time later, he was surprised to discoverthat the salts had burned an impression in it, just as if the plate had been exposed to light. Thesalts were emitting rays of some sort.
Considering the importance of what he had found, Becquerel did a very strange thing: heturned the matter over to a graduate student for investigation. Fortunately the student was arecent émigré from Poland named Marie Curie. Working with her new husband, Pierre, Curiefound that certain kinds of rocks poured out constant and extraordinary amounts of energy,yet without diminishing in size or changing in any detectable way. What she and her husbandcouldn’t know—what no one could know until Einstein explained things the followingdecade—was that the rocks were converting mass into energy in an exceedingly efficient way.
Marie Curie dubbed the effect “radioactivity.” In the process of their work, the Curies alsofound two new elements—polonium, which they named after her native country, and radium.
In 1903 the Curies and Becquerel were jointly awarded the Nobel Prize in physics. (MarieCurie would win a second prize, in chemistry, in 1911, the only person to win in bothchemistry and physics.)At McGill University in Montreal the young New Zealand–born Ernest Rutherford becameinterested in the new radioactive materials. With a colleague named Frederick Soddy hediscovered that immense reserves of energy were bound up in these small amounts of matter,and that the radioactive decay of these reserves could account for most of the Earth’s warmth.
They also discovered that radioactive elements decayed into other elements—that one dayyou had an atom of uranium, say, and the next you had an atom of lead. This was trulyextraordinary. It was alchemy, pure and simple; no one had ever imagined that such a thingcould happen naturally and spontaneously.
Ever the pragmatist, Rutherford was the first to see that there could be a valuable practicalapplication in this. He noticed that in any sample of radioactive material, it always took the same amount of time for half the sample to decay—the celebrated half-life—and that thissteady, reliable rate of decay could be used as a kind of clock. By calculating backwards fromhow much radiation a material had now and how swiftly it was decaying, you could work outits age. He tested a piece of pitchblende, the principal ore of uranium, and found it to be 700million years old—very much older than the age most people were prepared to grant theEarth.
In the spring of 1904, Rutherford traveled to London to give a lecture at the RoyalInstitution—the august organization founded by Count von Rumford only 105 years before,though that powdery and periwigged age now seemed a distant eon compared with the roll-your-sleeves-up robustness of the late Victorians. Rutherford was there to talk about his newdisintegration theory of radioactivity, as part of which he brought out his piece of pitchblende.
Tactfully—for the aging Kelvin was present, if not always fully awake—Rutherford notedthat Kelvin himself had suggested that the discovery of some other source of heat wouldthrow his calculations out. Rutherford had found that other source. Thanks to radioactivity theEarth could be—and self-evidently was—much older than the twenty-four million yearsKelvin’s calculations allowed.
Kelvin beamed at Rutherford’s respectful presentation, but was in fact unmoved. He neveraccepted the revised figures and to his dying day believed his work on the age of the Earth hismost astute and important contribution to science—far greater than his work onthermodynamics.
As with most scientific revolutions, Rutherford’s new findings were not universallyaccepted. John Joly of Dublin strenuously insisted well into the 1930s that the Earth was nomore than eighty-nine million years old, and was stopped only then by his own death. Othersbegan to worry that Rutherford had now given them too much time. But even withradiometric dating, as decay measurements became known, it would be decades before we gotwithin a billion years or so of Earth’s actual age. Science was on the right track, but still wayout.
Kelvin died in 1907. That year also saw the death of Dmitri Mendeleyev. Like Kelvin, hisproductive work was far behind him, but his declining years were notably less serene. As heaged, Mendeleyev became increasingly eccentric—he refused to acknowledge the existenceof radiation or the electron or anything else much that was new—and difficult. His finaldecades were spent mostly storming out of labs and lecture halls all across Europe. In 1955,element 101 was named mendelevium in his honor. “Appropriately,” notes Paul Strathern, “itis an unstable element.”
Radiation, of course, went on and on, literally and in ways nobody expected. In the early1900s Pierre Curie began to experience clear signs of radiation sickness—notably dull achesin his bones and chronic feelings of malaise—which doubtless would have progressedunpleasantly. We shall never know for certain because in 1906 he was fatally run over by acarriage while crossing a Paris street.
Marie Curie spent the rest of her life working with distinction in the field, helping to foundthe celebrated Radium Institute of the University of Paris in 1914. Despite her two NobelPrizes, she was never elected to the Academy of Sciences, in large part because after the deathof Pierre she conducted an affair with a married physicist that was sufficiently indiscreet toscandalize even the French—or at least the old men who ran the academy, which is perhapsanother matter.
For a long time it was assumed that anything so miraculously energetic as radioactivitymust be beneficial. For years, manufacturers of toothpaste and laxatives put radioactivethorium in their products, and at least until the late 1920s the Glen Springs Hotel in the FingerLakes region of New York (and doubtless others as well) featured with pride the therapeuticeffects of its “Radioactive mineral springs.” Radioactivity wasn’t banned in consumerproducts until 1938. By this time it was much too late for Madame Curie, who died ofleukemia in 1934. Radiation, in fact, is so pernicious and long lasting that even now herpapers from the 1890s—even her cookbooks—are too dangerous to handle. Her lab books arekept in lead-lined boxes, and those who wish to see them must don protective clothing.
Thanks to the devoted and unwittingly high-risk work of the first atomic scientists, by theearly years of the twentieth century it was becoming clear that Earth was unquestionablyvenerable, though another half century of science would have to be done before anyone couldconfidently say quite how venerable. Science, meanwhile, was about to get a new age of itsown—the atomic one.
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