万物简史英文版_比尔·布莱森-第21章

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he　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鈥攖hat鈥檚　equivalent　to　traveling　from　london　to　equatorial　guinea鈥攁nd　depositedhim　at　the　institute　of　pedagogy。　worn　out　by　her　efforts；　she　died　soon　after。

mendeleyev　dutifully　pleted　his　studies　and　eventually　landed　a　position　at　the　localuniversity。　there　he　was　a　petent　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鈥攅ither　by　atomic　weight（using　avogadro鈥檚　principle）　or　by　mon　properties　（whether　they　were　metals　or　gases；for　instance）。　mendeleyev鈥檚　breakthrough　was　to　see　that　the　two　could　be　bined　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鈥攊n　a　sense　toharmonize鈥攁t　every　eighth　place　along　the　scale。　slightly　unwisely；　for　this　was　an　ideawhose　time　had　not　quite　yet　e；　newlands　called　it　the　law　of　octaves　and　likened　thearrangement　to　the　octaves　on　a　piano　keyboard。　perhaps　there　was　something　in　newlands鈥檚manner　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鈥攚hat　is　known　as　theiratomic　number。

the　structure　of　atoms　and　the　significance　of　protons　will　e　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　es　first　on　the　chart；　uraniumhas　ninety…two　protons；　and　so　it　es　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鈥檛　known　or　understood。　hydrogen　is　the　most　mon　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鈥攊ts　existence　hadn鈥檛　even　been　suspectedbefore　that鈥攁nd　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鈥檛　beisolated　until　1895。　even　so；　thanks　to　mendeleyev鈥檚　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。　鈥渨ithout　adoubt；　the　periodic　table　of　the　chemical　elements　is　the　most　elegant　organizational　chartever　devised；鈥潯�wrote　robert　e。　krebs　in　the　history　and　use　of　our　earth鈥檚　chemicalelements；　and　you　can　find　similar　sentiments　in　virtually　every　history　of　chemistry　in　print。

today　we　have　鈥�120　or　so鈥潯�known　elements鈥攏inety…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鈥檚　dayjust　sixty…three　elements　were　known；　but　part　of　his　cleverness　was　to　realize　that　theelements　as　then　known　didn鈥檛　make　a　plete　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　鈥減urely　speculative；鈥潯�but　what　is　certain　is　thatanything　that　is　found　will　fit　neatly　into　mendeleyev鈥檚　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　茅migr茅　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鈥檛　know鈥攚hat　no　one　could　know　until　einstein　explained　things　the　followingdecade鈥攚as　that　the　rocks　were　converting　mass　into　energy　in　an　exceedingly　efficient　way。

marie　curie　dubbed　the　effect　鈥渞adioactivity。鈥潯�in　the　process　of　their　work；　the　curies　alsofound　two　new　elements鈥攑olonium；　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鈥揵orn　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鈥檚　warmth。

they　also　discovered　that　radioactive　elements　decayed　into　other　elements鈥攖hat　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鈥攖he　celebrated　half…life鈥攁nd　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鈥攙ery　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鈥攖he　august　organization　founded　by　count　von　rumford　only　105　years　before；though　that　powdery　and　periwigged　age　now　seemed　a　distant　eon　pared　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鈥攆or　the　aging　kelvin　was　present；　if　not　always　fully　awake鈥攔utherford　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鈥攁nd　self…evidently　was鈥攎uch　older　than　the　twenty…four　million　yearskelvin鈥檚　calculations　allowed。

kelvin　beamed　at　rutherford鈥檚　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鈥攆ar　greater　than　his　work　onthermodynamics。

as　　with　　most　　scientific　　revolutions；　　rutherford鈥檚　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鈥檚　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鈥攈e　refused　to　acknowledge　the　existenceof　radiation　or　the　electron　or　anything　else　much　that　was　new鈥攁nd　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。　鈥渁ppropriately；鈥潯�notes　paul　strathern；　鈥渋tis　an　unstable　element。鈥�

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鈥攏otably　dull　achesin　his　bones　and　chronic　feelings　of　malaise鈥攚hich　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　scien