,,a/ronomical ,,discov]y ,illu/ration3 ,,a/ronom]s ,,royal4 ,,a/ronomical ,,discov]y ,,by ,,h]b]t ,,hall ,,turn]1 ,d4,sc41 ,f4,r4,s4 ,,savilian ,,pr(essor ,,( ,,a/ronomy ,,9 ,,! ,,univ]sity ,,( ,,ox=d ,,) ,,plates ,,london ,,edw>d ,,arnold #da #dc ,,maddox ,,/reet1 ,w4 #aijd 7,all rights res]v$7 ,,to ,,edw>d ,,em]son ,,b>n>d ,,a/ronomical ,,discov]] ,,^! ,,pages ,,are ,,inscrib$ ,,9 ,,memory ,,( ,,nev]-,,to-,,be-,,=gott5 ,,days ,,sp5t ,,) ,,him ,,at ,,! ,,y]kes ,,obs]vatory ,,( ,,! ,,univ]sity ,,( ,,*icago ,,preface ,! aim ( ! foll[+ pages is to illu/rate1 by ! /udy ( a few examples *os5 almo/ at r&om1 ! v>iety 9 "* ( a/ronomical discov]ies4 ,an attempt has inde$ be5 made to arrange ! half-doz5 examples1 once select$1 into a r\gh sequ5ce accord+ to ! am\nt ( *ance associat$ ) ! discov]y1 ?\gh f ?is po9t ( view ,*apt] ,,iv4 %\ld come fir/2 b ,i d n lay mu* /ress ^u x4 ,!re is und\bt$ly an elem5t ( luck 9 mo/ discov]ies4 ,! bigge/ /rokes are all luck1 writes a bro!r a/ronom] :o _h done me ! hon\r to glance at a few pages1 b a man mu/ n drop 8 cat*es4 ,h y ev] read ,montaigne's essay ',( ,glory'8 ,x is wor? read+4 ,*ange w> & glory to discov]y & x is exactly ! same !me4 ,if y are look+ = a motto y w f9d a score 9 x4 ,inde$ ev5 9 cases su* z ^? 9 ,*apt]s ,v4 & ,,vi41 :]e a discov]y is made by turn+ ov] a heap ( rubbi%--decl>$ su* by exp]ts & ab&on$ accord+ly--we in/9ctively feel t ! f9d+ ( some?+ valuable 0 especially =tunate4 ,we %\ld sc>cely recomm5d su* wa/e mat]ial z ! be/ hunt+ gr\nd = gems4 ,! *apt]s correspond approximately to a s]ies ( six lectures deliv]$ at ! ,univ]sity ( ,*icago 9 ,augu/ #aijd1 at ! hospitable invitation ( ,presid5t ,h>p]4 ,!y af=d$ me ! opportunity ( see+ some?+ ( ?is wond]ful ,univ]sity1 only a doz5 ye>s old & yet s amaz+ly vigor\s2 & especially ( its obs]vatory 7! ,y]kes obs]vatory1 situat$ eighty miles away on ,lake ,g5eva71 :i* is only eight ye>s old & yet has tak5 its place 9 ! =emo/ rank4 ,= ^! opportunities ,i v5ture "h to put on record my grateful ?anks4 ,9 a portion ( ! fir/ *apt] x w be obvi\s t ,i am indebt$ to ,miss ,cl]ke's ,hi/ory ( ,a/ronomy 9 ! ,n9ete5? ,c5tury2 9 ! second to ,pr(essor ,r4 ,a4 ,sampson's ,memoir on ! ,adams ,,mss42 9 ! ?ird to ,rigaud's ,life ( ,bradley4 ,!re are o!r debts :i* ,i hope are duly ackn[l$g$ 9 ! text4 ,my grateful ?anks are due to ,mr4 ,f4 ,a4 ,bellamy = ! c>e ) :i* he has read ! pro(s2 & ,i am indebt$ = p]mission to publi% illu/rations to ! ,royal ,a/ronomical ,society1 ! ,a/ronom] ,royal1 ! editors ( ,! ,obs]vatory1 ! ,cambridge ,univ]sity ,press1 ! ,h>v>d ,college ,obs]vatory1 ! ,y]kes ,obs]vatory1 & ! liv+ repres5tatives ( two portraits4 ,h4 ,h4 ,,turn]4 ,,univ]sity ,,obs]vatory1 ,,ox=d1 ,novemb] #i1 #aijd4 ,,cont5ts ,,page ,,*apt] ,i ,,uranus ,,& ,,eros #a ,,*apt] ,,ii ,,! ,,discov]y ,,( ,,neptune #ch ,,*apt] ,,iii ,,bradley',s ,,discov]ies ,,( ,,! ,,ab]ration ,,( ,,light ,,& ,,( ,,! ,,nutation ,,( ,,! ,,e>?',s ,,axis #hf ,,*apt] ,,iv ,,accid5tal ,,discov]ies #aba ,,*apt] ,v ,,s*wabe ,,& ,,! ,,sun-,,spot ,,p]iod #aee ,,*apt] ,,vi ,,! ,,v>iation ,,( ,,latitude #agg ,,index #bba ,,li/ ,,( ,,plates ,,plate ,i4 ,,portrait ,,( ,j4 ,c4 ,,adams ,to face page #bb ,,ii4 ,,portrait ,,( ,a4 ,,graham #bb ,,iii4 ,,portrait ,,( ,u4 ,j4 ,,le ,,v]ri] #fj ,,iv4 ,,portrait ,,( ,j4 ,g4 ,,galle #fj ,v4 ,,corn] ,,( ,,! ,,b]l9 ,,map ,,by ,,! ,,use ,,( ,,:i* ,,galle ,,f\nd ,,neptune #hb ,,vi4 ,,a/ronom]s ,,royal ,frontispiece ,,vii4 ,,great ,,comet ,,( ,,nov4 #g1 #ahhb ,to face page #abb ,,viii4 ,,! ,,ox=d ,,new ,,/> #adb ,,ix4 ,,nebulosity ,,r\nd ,,nova ,,p]sei #adf ,x4 ,,sun-,,spots ,,at ,,gre5wi*1 ,,feb4 #ah ,,& #ai1 #ahid #aeh ,,xi4 ,,sun-,,spots ,,at ,,gre5wi*1 ,,feb4 #bj ,,& #ba1 #ahid #afb ,,xii4 ,,numb] ,,( ,,sun-,,spots ,,comp>$ ,,) ,,daily ,,range ,,( ,,magnetic ,,decl9ation ,,& ,,daily ,,range ,,( ,,magnetic ,,horizontal ,,=ce #afd ,,xiii4 ,,gre5wi* ,,magnetic ,,curves1 #ahei-fj #aff ,,xiv4 ,,gre5wi* ,,magnetic ,,curves1 #ahda-ahfj #aff ,,xv4 ,,sun-,,spots ,,& ,,turns ,,( ,,vane #agj ,,errata ,page #acc1 l9e #bg1 = #bjj />s read #bjj />s p] h\r4 #ade1 ,see note on page #bbj4 #adf1 bottom ( page4 ,?is nebulosity 0 fir/ discov]$ by ,dr4 ,max ,wolf ( ,heidelb]g4 ,see ,a/r4 ,na*r4 #cgcf4 #aha1 l9e #ag1 = obs]vation read ab]ration4 ,,a/ronomical ,,discov]y ,,*apt] ,i ,,uranus ,,& ,,eros ,sid5ote3 ,popul> view ( discov]y4 ,discov]y is expect$ f an a/ronom]4 ,! lay m9d sc>cely ?9ks ( a naturali/ n[adays discov]+ new animals1 or ( a *emi/ z f9d+ new elem5ts save on r>e occasions2 b x does ?9k ( ! a/ronom] z mak+ discov]ies4 ,! popul> imag9ation pictures him sp5d+ ! :ole night 9 wat*+ ! skies f a high t[] ?r\gh a long telescope1 occasionally rew>d$ by ! f9d+ ( some?+ new1 )\t mu* m5tal ef=t4 ,i propose to comp>e ) ?is romantic picture "s ( ! actual facts1 "s ( ! ways 9 :i* discov]ies are really made2 & if we f9d t ! image & ! reality diff]1 ,i hope t ! romance w nev]!less n be !reby de/roy$1 b may adapt itself to conditions m closely resembl+ ! facts4 ,sid5ote3 ,keats' l9es4 ,! popul> conception f9ds expression 9 ! l9es ( ,keats3-- ,!n felt ,i l "s wat*] ( ! skies ,:5 a new planet swims into 8 k54 ,keats 0 born 9 #agie1 publi%$ 8 fir/ volume ( poems 9 #ahag1 & di$ 9 #ahba4 ,at ! "t :5 he wrote ! discov]y ( planets 0 comp>atively novel 9 human exp]i5ce4 ,uranus _h be5 f\nd by ,william ,h]s*el 9 #agha1 & 9 ! ye>s #ahjj to #ahjg foll[$ ! fir/ f\r m9or planets1 a numb] de/9$ to rema9 )\t additions = ne>ly =ty ye>s4 ,x w\ld be absurd to read any exact allusion into ! words quot$1 :5 we rememb] ! :ole circum/ances "u :i* !y 7 writt52 b p]haps ,i may be =giv5 if ,i comp>e !m especially ) ! actual discov]y ( ! planet ,uranus1 = ! reason t ?is 0 by f> ! l>ge/ ( ! five--f> l>g] ?an any o!r planet kn[n except ,jupit] & ,saturn1 :ile ! o!rs 7 f> small]--& t ,keats is us+ ?r\gh\t ! poem metaphors drawn f ! fir/ glimpses ( va/ expanses ( l& or wat]4 ,p]haps ,i may reproduce ! :ole sonnet4 ,8 fri5d ,c4 ,c4 ,cl>ke _h put be=e him ,*apman's p>aphrase ( ,hom]1 & !y sat up till daylight to read x1 ,keats %\t+ ) delight z "s passage ( especial en]gy /ruck 8 imag9ation4 ,at t5 o'clock ! next morn+ ,mr4 ,cl>ke f\nd ! sonnet on 8 breakfa/-table4 ,,sonnet ,,xi ,on fir/ look+ into ,*apman's ,hom] ,mu* h ,i travell'd 9 ! realms ( gold1 ,& _m goodly /ates & k+doms se52 ,r\nd _m we/]n isl&s h ,i be5 ,:i* b>ds 9 fealty to ,apollo hold4 ,(t ( "o wide expanse _h ,i be5 told ,t deep-br['d ,hom] rul$ z 8 demesne2 ,yet did ,i nev] brea! its pure s]5e ,till ,i he>d ,*apman speak out l\d & bold3 ,!n felt ,i l "s wat*] ( ! skies ,:5 a new planet swims into 8 k52 ,or l /\t ,cortez :5 ) eagle eyes ,he />'d at ! ,pacific--& all 8 m5 ,look'd at ea* o!r ) a wild surmise-- ,sil5t1 ^u a peak 9 ,d>i54 ,sid5ote3 ,comp>ison ) discov]y ( ,uranus4 ,let u !n1 z our fir/ example ( ! way 9 :i* a/ronomical discov]ies are made1 turn to ! discov]y ( ! planet ,uranus1 & see h[ x corresponds ) ! popul> conception z voic$ by ,keats4 ,9 "o respect 8 words are true to ! life or ! lett]4 ,if ev] !re 0 a wat*] ( ! skies1 ,william ,h]s*el 0 entitl$ to ! "n4 ,x 0 8 cu/om to wat* !m ! :ole night ?r\gh1 f ! e>lie/ possible mom5t to daybreak2 & ! fruits ( 8 lab\rs 7 _m & v>i\s almo/ beyond belief4 ,b did ! planet swim into 8 k58 ,let u turn to ! orig9al ann\ncem5t ( 8 discov]y z giv5 9 ! ,philosophical ,transactions = #agha4 ,,philosophical ,,transactions1 #agha ,,xxxii4--,,acc\nt ,,( ,a ,,comet ,,by ,,mr4 ,,h]s*el1 ,f4,r4,s4 7,communicat$ by ,dr4 ,watson1 jun41 ( ,ba?1 ,f4,r4,s47 ,read ,april #bf1 #agha ,sid5ote3 ,orig9al ann\ncem5t4 ,on ,tuesday ! #ac? ( ,m>*1 betwe5 t5 & elev5 9 ! ev5+1 :ile ,i 0 exam9+ ! small />s 9 ! neighb\rhood ( ,h ,gem9orum1 ,i p]ceiv$ "o t appe>$ visibly l>g] ?an ! re/2 be+ /ruck ) its uncommon magnitude1 ,i comp>$ x to ,h ,gem9orum & ! small /> 9 ! qu>tile betwe5 ,auriga & ,gem9i1 & f9d+ x to be s mu* l>g] ?an ei!r ( !m1 suspect$ x to be a comet4 ,i 0 !n engag$ 9 a s]ies ( obs]vations on ! p>allax ( ! fix$ />s1 :i* ,i hope soon to h ! hon\r ( lay+ be=e ! ,royal ,society2 & ^? obs]vations requir+ v high p[]s1 ,i _h ready at h& ! sev]al magnifi]s ( #bbg1 #dfj1 #icb1 #aecf1 #bjaj1 c41 all :i* ,i h successfully us$ ^u t occasion4 ,! p[] ,i _h on :5 ,i fir/ saw ! comet 0 #bbg4 ,f exp]i5ce ,i knew t ! diamet]s ( ! fix$ />s are n proportionally magnifi$ ) high] p[]s z ! planets are2 !re=e ,i n[ put on ! p[]s ( #dfj & #icb1 & f\nd ! diamet] ( ! comet increas$ 9 proportion to ! p[]1 z x ought to be1 on a supposition ( its n be+ a fix$ />1 :ile ! diamet]s ( ! />s to :i* ,i comp>$ x 7 n increas$ 9 ! same ratio4 ,moreov]1 ! comet be+ magnifi$ mu* beyond :at its light w\ld admit (1 appe>$ hazy & ill-def9$ ) ^! great p[]s1 :ile ! />s pres]v$ t lu/re & di/9ctness :i* f _m ?\s& obs]vations ,i knew !y w\ld reta94 ,! sequel has %[n t my surmises 7 well f\nd$1 ?is prov+ to be ! ,comet we h lately obs]v$4 ,i h r$uc$ all my obs]vations ^u ?is comet to ! foll[+ tables4 ,! fir/ conta9s ! measures ( ! gradual increase ( ! comet's diamet]4 ,! micromet]s ,i us$1 :5 e circum/ance is fav\rable1 w measure extremely small angles1 su* z d n exce$ a few seconds1 true to #f1 #h1 or #aj ?irds at mo/2 & 9 ! wor/ situations true to #bj or #cj ?irds2 ,i h !re=e giv5 ! measures ( ! comet's diamet] 9 seconds & ?irds4 ,& ! p>ts ( my micromet] be+ ?us r$uc$1 ,i h also giv5 all ! re/ ( ! measures 9 ! same mann]2 ?\gh 9 l>ge di/ances1 su* z "o1 two1 or ?ree m9utes1 s great an exactness1 = sev]al reasons1 is n pret5d$ to4 ,sid5ote3 ,call$ fir/ a comet4 ,sid5ote3 ,o!r obs]v]s w\ld n h f\nd x at all4 ,at fir/ sight ?is seems to be ! wrong ref]5ce1 = x speaks ( a new comet1 n a new planet4 ,b x is inde$ ( ,uranus t ,h]s*el is speak+2 & s little did he realise ! full magnitude ( 8 discov]y at once1 t he ann\nc$ x z t ( a comet2 & a comet ! object 0 call$ = "s mon?s4 ,attempts 7 made to calculate its orbit z a comet1 & broke d[n2 & x 0 only aft] mu* "w ( ?is k9d _h be5 done t ! real nature ( ! object began to be suspect$4 ,b f> m /rik+ ?an ?is misconception is ! display ( skill necess>y to detect any peculi>ity 9 ! object at all4 ,among a numb] ( />s "o seem$ some:at exceptional 9 size1 b ! diff]5ce 0 only j suffici5t to awak5 suspicion 9 a ke5-ey$ ,h]s*el4 ,w\ld any o!r obs]v] h notic$ ! diff]5ce at all8 ,c]ta9ly sev]al good obs]v]s _h look$ at ! object be=e1 & look$ at x ) ! c>e necess>y to record its position1 )\t not+ any peculi>ity4 ,_! obs]vations 7 recov]$ subsequ5tly & us$ to fix ! orbit ( ! new planet m accurately4 ,i %all rem9d y 9 ! next *apt] t ,uranus _h be5 obs]v$ 9 ?is way no less ?an sev5te5 times by fir/-rate obs]v]s )\t excit+ _! att5tion to any?+ rem>kable4 ,! fir/ occasion 0 9 #afij1 ne>ly a c5tury be=e ,h]s*el's gr& discov]y1 & ^! *ance obs]vations1 :i* lay s long unnotic$ z 9 "s way errone\s1 subsequ5tly prov$ to be ( ! utmo/ value 9 fix+ ! orbit ( ! new planet4 ,b !re is ev5 m /rik+ te/imony ?an ?is to ! exceptional nature ( ,h]s*el's a*ievem5t4 ,x is a common exp]i5ce 9 a/ronomy t an obs]v] may fail to notice 9 a g5]al scrut9y "s ph5om5on :i* he c see p]fectly well :5 8 att5tion is direct$ to x3 :5 a man has made a discov]y & o!rs are told :at to look =1 !y (t5 see x s easily t !y are fill$ ) amazem5t & *agr9 t !y nev] saw x be=e4 ,n s 9 ! case ( ,uranus4 ,at lea/ two great a/ronom]s1 ,lal&e & ,messi]1 h left on record _! a/oni%m5t t ,h]s*el c\ld diff]5tiate x f an ord9>y /> at all2 = ev5 :5 in/ruct$ :]e to look & :at to look =1 !y _h ! greate/ difficulty 9 f9d+ x4 ,i give a translation ( ,messi]'s words1 :i* ,h]s*el records 9 ! pap] already quot$ ann\nc+ ! discov]y3-- ,no?+ 0 m difficult ?an to recognise x2 & ,i _c conceive h[ y h be5 able to return sev]al times to ?is /> or comet2 = absolutely x has be5 necess>y to obs]ve x = sev]al consecutive days to p]ceive t x 0 9 motion4 ,sid5ote3 ,no swimm+ into k54 ,we _c1 !re=e1 fit ! facts to ,keats' v]sion ( !m4 ,! planet did n maje/ically reveal itself to a m]ely passive obs]v]3 r did x1 assum+ ! disguise ( an ord9>y />1 evade detection to ! utmo/ ( its p[]2 s t ! ke5e/ eye1 ! mo/ al]t att5tion1 ! mo/ det]m9$ foll[+ up ( a m]e h9t1 7 all ne$$ to unmask x4 ,b is ! romance necess>ily gone8 ,if ano!r ,keats c\ld arise & "k ! facts1 c\ld he n co9 a new] & a tru] phrase = u :i* w\ld /ill s\nd z sweetly 9 our e>s8 ,sid5ote3 ,?\gh ?is may happ5 at times4 ,sid5ote3 ,"n ( new planet4 ,i mu/ gu>d aga9/ a possible misconception4 ,i d n mean to convey t a/ronomical discov]ies are n occasionally made some:at 9 ! mann] s beautifully pictur$ by ,keats4 ,?ree ye>s ago a p]si/5t wat*] ( ! skies1 ,dr4 ,&]son ( ,ed9burgh1 sudd5ly caught sight ( a brilliant new /> 9 ,p]seus2 ?\gh "h fla%$ into 8 k5 w\ld p]haps be a m suitable phrase ?an swam4 ,& comets h be5 detect$ by a m]e glance at ! heav5s )\t s5sible ef=t or c>e on ! "p ( ! discov]]4 ,b ^! may be fairly call$ exceptions2 9 ! va/ majority ( cases h>d "w & a ke5 eye are necess>y to make ! discov]y4 ,! relative importance ( ^! two factors ( c\rse v>ies 9 diff]5t cases2 = ! detection ( ,uranus p]haps ! ke5 eye may be put 9 ! fir/ place1 ?\gh we mu/ n =get ! dilig5t wat*+ :i* gave x opportunity4 ,o!r cases ( planet>y discov]y may be attribut$ m completely to dilig5ce alone1 z we %all pres5tly see4 ,b be=e leav+ ,uranus = !m ,i %\ld l to recall ! circum/ances att5d+ ! nam+ ( ! planet4 ,h]s*el propos$ to call x ,georgium ,sidus 9 hon\r ( 8 patron1 ,k+ ,george ,,iii41 & z ! be/ way ( mak+ 8 wi%es kn[n1 wrote ! foll[+ lett] to ! ,presid5t ( ! ,royal ,society1 :i* is pr9t$ at ! beg9n+ ( ! ,philosophical ,transactions = #aghc4 ,a ,lett] f ,,william ,,h]s*el1 ,esq41 ,f4,r4,s41 to ,sir ,,joseph ,,banks1 ,b>t41 ,p4,r4,s4 ,sir1--,by ! obs]vations ( ! mo/ em95t a/ronom]s 9 ,europe x appe>s t ! new />1 :i* ,i _h ! hon\r ( po9t+ out to !m 9 ,m>* #agha1 is a ,prim>y ,planet ( our ,sol> ,sy/em4 ,a body s ne>ly relat$ to u by its simil> condition & situation 9 ! unb\nd$ expanse ( ! />ry heav5s1 mu/ (t5 be ! subject ( conv]sation1 n only ( a/ronom]s1 b ( e lov] ( sci5ce 9 g5]al4 ,?is consid]ation !n makes x necess>y to give x a "n :]eby x may be di/+ui%$ f ! re/ ( ! planets & fix$ />s4 ,sid5ote3 ,georgium ,sidus4 ,9 ! fabul\s ages ( anci5t times1 ! appellations ( ,m]cury1 ,v5us1 ,m>s1 ,jupit]1 & ,saturn 7 giv5 to ! planets z be+ ! names ( _! pr9cipal h]oes & div9ities4 ,9 ! pres5t m philosophical era1 x w\ld h>dly be all[able to h rec\rse to ! same me?od1 & call on ,juno1 ,pallas1 ,apollo1 or ,m9]va = a "n to our new heav5ly body4 ,! fir/ consid]ation 9 any p>ticul> ev5t1 or rem>kable incid5t1 seems to be its *ronology3 if 9 any future age x %\ld be ask$1 :5 ?is la/ f\nd planet 0 discov]$8 ,x w\ld be a v satisfactory answ] to say1 ',9 ! reign ( ,k+ ,george ! ,?ird4' ,z a philosoph] !n1 ! "n ,,georgium ,,sidus pres5ts itself to me1 z an appellation :i* w conv5i5tly convey ! in=mation ( ! "t & c\ntry :]e & :5 x 0 br\ght to view4 ,b z a subject ( ! be/ ( k+s1 :o is ! lib]al protector ( e art & sci5ce2 z a native ( ! c\ntry f :5ce ?is illu/ri\s family 0 call$ to ! ,briti% ?rone2 z a memb] ( t ,society :i* fl\ri%es by ! di/+ui%$ lib]ality ( its royal patron2 &1 la/ ( all1 z a p]son n[ m imm$iately "u ! protection ( ?is excell5t mon>*1 & ow+ ev]y?+ to 8 unlimit$ b\nty2--,i _c b wi% to take ?is opportunity ( express+ my s5se ( gratitude by giv+ ! "n ,georgium ,sidus1 ,georgium ,sidus ----jam nunc assuesce voc>i1 ,virg4 ,georg4 to a /> :i* 7) respect to u7 fir/ began to %9e "u 8 auspici\s reign4 ,by address+ ?is lett] to y1 ,sir1 z ,presid5t ( ! ,royal ,society1 ,i take ! mo/ effectual me?od ( communicat+ t "n to ! lit]ati ( ,europe1 :i* ,i hope !y w receive ) pleasure4--,i h ! hon\r to be1 ) ! greate/ respect1 ,sir1 y\r mo/ humble & mo/ ob$i5t s]vant1 ,w4 ,,h]s*el4 ,sid5ote3 ,h]s*el4 ,?is lett] rem9ds u h[ long x 0 s9ce a new "n _h be5 requir$ = a new planet1--to f9d a simil> occasion ,h]s*el _h to g to ! almo/ prehi/oric pa/1 :5 ! names ( h]oes & div9ities 7 giv5 to ! planets4 ,x is1 p]haps1 n unnatural t he %\ld h consid]$ an entirely new dep>ture appropriate = a discov]y sep>at$ by s great a l5g? ( "t f ! o!rs2 b 8 views 7 n g5]ally accept$1 especially on ! ,cont95t4 ,lal&e c\rte\sly propos$ ! "n ( ,h]s*el = ! new planet1 9 hon\r ( ! discov]]1 & ?is "n 0 us$ 9 ,france2 b ,bode1 on ! o!r h&1 0 9 fav\r ( reta9+ ! old practice simply1 & call+ ! new planet ,uranus4 ,all ?ree names seem to h be5 us$ = _m ye>s4 ,only ! o!r day ,i 0 int]e/$ to see an old pack ( c>ds1 us$ = play+ a p>l\r game ( ,a/ronomy1 9 :i* ! "n ,h]s*el is us$4 ,! own] told me t !y _h belong$ to 8 gr&fa!r2 & ! date ( publication 0 #ahbi1 & ! place ,london1 s t ?is "n 0 9 common use 9 ,engl& ne>ly half a c5tury aft] ! actual discov]y2 ?\gh 9 ! ,engli% ,nautical ,almanac ! "n ! ,georgian 7app>5tly pref]r$ to ,h]s*el's ,georgium ,sidus7 0 be+ us$ (ficially aft] #agia1 & did n disappe> f t "w until #ahea 7publi%$ 9 #ahdg47 ,sid5ote3 ,uranus f9ally adopt$4 ,x w\ld appe> to h be5 ! discov]y ( ,neptune1 ) :i* we %all deal 9 ! next *apt]1 :i* l$ to ?is (ficial *ange2 = 9 ! volume = #ahea is includ$ ,adams' acc\nt ( 8 discov]y ) ! title-- ,,on ,,! ,,p]turbations ,,( ,,uranus1 & !re 0 ?us a def9ite reason = avoid+ two names = ! same planet 9 ! same "w4 ,b ,le ,v]ri]'s pap] on ! same topic at ! same date /ill uses ! "n ,h]s*el = ! planet4 ,sid5ote3 ,bode's law4 ,! discov]y ( ,neptune1 z we %all see1 0 totally diff]5t 9 "* f t ( ,uranus4 ,! latt] may be describ$ z ! f9d+ ( some?+ by an obs]v] :o 0 look+ = any?+2 ,neptune 0 ! f9d+ ( some?+ def9itely s\ght =1 & def9itely po9t$ out by a mo/ successful & brilliant piece ( me?odical "w4 ,b be=e t "t sev]al planets _h be5 f\nd1 z ! practical result ( a def9ite se>*1 al?\gh ! guid+ pr9ciple 0 su* z _c comm& our admiration to q ! same ext5t z 9 ! case ( ,neptune4 ,to expla9 x ,i mu/ say some?+ ( ! relative sizes ( ! orbits 9 :i* planets move r\nd ! sun4 ,^! orbits are1 z we "k1 ellipses2 b !y are v ne>ly circles1 &1 exclud+ ref9em5ts1 we may consid] !m z circles1 ) ! sun at ! c5tre ( ea*1 s t we may talk ( ! di/ance ( any planet f ! sun z a con/ant quantity )\t s]i\s error4 ,n[ if we arrange ! planet>y di/ances 9 ord]1 we %all notice a rem>kable connection betwe5 ! t]ms ( ! s]ies4 ,"h is a table %[+ ?is connection4 ,,table ,,( ,,! ,,di/ances ,,( ,,! ,,planets ,,f ,,! ,,sun1 ,,%[+ ,,bode',s ,,law4 ---------------------------------------- ------------ ,"n ( ,di/ance f ,bode's ,law ,planet4 ,sun1 tak+ 7orig9ally =mulat$ t ( ,e>? by ,titius1 b br\ght z #aj4 into notice by ,bode74 ---------------------------------------- ------------ ,m]cury #d #d #j #d ,v5us #g #d #c #g ,! ,e>? #aj #d #f #aj ,m>s #ae #d #ab #af 7 7 7 7 #d #bd #bh ,jupit] #eb #d #dh #eb ,saturn #ie #d #if #ajj ,uranus #aib #d #aib #aif ---------------------------------------- ------------ ,sid5ote3 ,gap 9 ! s]ies sugge/+ unkn[n planet4 ,sid5ote3 ,se>* = x4 ,sid5ote3 ,accid5tal discov]y4 ,if we write d[n a s]ies ( #d's1 & !n add ! numb]s #c1 #f1 #ab1 & s on1 ea* =m$ by d\bl+ ! la/1 we get numb]s repres5t+ v ne>ly ! planet>y di/ances1 :i* are %[n approximately 9 ! second column4 ,b ?ree po9ts call = notice4 ,fir/ly1 ! numb] be=e #c %\ld be #a-a_/b1 & n z]o1 to agree ) ! re/4 ,secondly1 !re is a gap1 or r 0 a gap1 aft] ! discov]y ( ,uranus1 betwe5 ,m>s & ,jupit]2 & ?irdly1 we see t :5 ,uranus 0 discov]$1 & its di/ance f ! sun det]m9$1 ?is di/ance 0 f\nd to fall 9 satisfactorily ) ?is law1 :i* 0 fir/ /at$ by ,titius ( ,witt5b]g4 ,?is ?ird fact naturally attract$ att5tion4 ,no explanation ( ! s-call$ law 0 kn[n at ! "t2 nor is any kn[n ev5 yet1 ?\gh we may be said to h "s glimm]+s ( a possible cause2 & 9 ! abs5ce ( su* explanation x mu/ be reg>d$ z m]ely a curi\s co9cid5ce4 ,b ! *ances t we are 9 ! pres5ce ( a m]e co9cid5ce dim9i% v quickly ) ea* new t]m add$ to ! s]ies1 & :5 x 0 f\nd t ,h]s*el's new planet fitt$ 9 s well at ! end ( ! arrangem5t1 ! "q arose :e!r ! gap above notic$ 0 real1 or :e!r !re 0 p]haps ano!r planet :i* _h hi!rto escap$ notice1 revolv+ 9 an orbit repres5t$ by ?is blank t]m4 ,?is "q _h inde$ be5 ask$ ev5 be=e ! discov]y ( ,uranus1 by ,bode1 a "y a/ronom] ( ,b]l92 & = fifte5 ye>s he kept /eadily 9 view ?is idea ( f9d+ a planet to fill ! vacant int]val4 ,! se>* w\ld be a v ardu\s "o1 involv+ a c>eful scrut9y1 n p]haps ( ! :ole heav5s1 b ( a consid]able portion ( x along ! ,zodiac2 too great = "o w\ld-be discov]] s+le-h&$2 b 9 ,septemb] #ahjj ,bode succe$$ 9 organis+ a b& ( six ,g]man a/ronom]s 7includ+ himself7 = ! purpose ( conduct+ ?is se>*4 ,!y divid$ ! ,zodiac into tw5ty-f\r zones1 & 7 assign+ ! zones to ! diff]5t obs]v]s1 :5 !y 7 />tl$ by ! news t ! miss+ planet _h be5 accid5tally f\nd by ,piazzi 9 ! con/ellation ,taurus4 ,! discov]y 0 made some:at dramatically on ! fir/ ev5+ ( ! n9ete5? c5tury 7,janu>y #a1 #ahja74 ,piazzi 0 n look+ = a planet at all1 b exam9+ an error made by ano!r a/ronom]2 & 9 ! c\rse ( ?is "w he record$ ! position ( a /> ( ! eigh? magnitude4 ,return+ to x on ! next night1 x seem$ to him t x _h slightly mov$ we/w>ds1 & on ! foll[+ night ?is suspicion 0 confirm$4 ,rem>k t 9 ?is case no peculi> appe>ance 9 ! /> sugge/$ t x might be a comet or planet1 z 9 ! case ( ! discov]y ( ,uranus4 ,we are n unfair 9 ascrib+ ! discov]y to pure accid5t1 al?\gh we mu/ n =get t a c>eless obs]v] might easily h miss$ x4 ,piazzi 0 any?+ b c>eless1 & wat*$ ! new object assidu\sly till ,febru>y #aa?1 :5 he became dang]\sly ill2 b he _h writt51 on ,janu>y #bcrd1 to ,oriani ( ,milan1 & to ,bode at ,b]l9 on ! foll[+ day4 ,^! lett]s1 h[ev]1 did n rea* ! recipi5ts 79 ^? days ( leisurely po/al s]vice7 until ,april #e? & ,m>* #bj? respectively2 & we c imag9e ! mix$ feel+s ) :i* ,bode he>d t ! discov]y :i* he _h contemplat$ = fifte5 ye>s1 & = :i* he 0 j ab\t to organise a dilig5t se>*1 0 ?us curi\sly snat*$ f him4 ,sid5ote3 ,hegel's =eca/4 ,m curi\s /ill mu/ h seem$ ! intellig5ce to a "y philosoph] ( ,j5a nam$ ,hegel1 :o has s9ce become fam\s1 b :o _h j imp]ill$ 8 future reputation by publi%+ a diss]tation prov+ conclusively t ! numb] ( ! planets c\ld n be great] ?an sev51 & p\r+ scorn on ! project$ se>* ( ! half-doz5 en?usia/s :o 7 propos+ to f9d a new planet m]ely to fill up a gap 9 a num]ical s]ies4 ,sid5ote3 ,! planet lo/ aga94 ,! s5sation caus$ by ! news ( ! discov]y 0 int5sifi$ by anxiety le/ ! new planet %\ld already h be5 lo/2 = x _h mean:ile travell$ too close to ! sun = fur!r obs]vation1 & ! only mat]ial available = calculat+ its orbit1 & s pr$ict+ its place 9 ! heav5s at future dates1 0 af=d$ by ! few obs]vations made by ,piazzi4 ,0 x possible to calculate ! orbit f su* sl5d] mat]ial8 ,x w\ld take too long to expla9 fully ! enorm\s difficulty ( ?is problem1 b "s notion ( x may be obta9$1 by ^? unacqua9t$ ) ma!matics1 f a r\gh analogy4 ,if we are giv5 a portion ( a circle1 we c1 ) ! help ( a pair ( compasses1 complete ! circle3 we c f9d ! c5tre f :i* ! arc is /ruck1 ei!r by geometrical me?ods1 or by a few exp]im5tal trials1 & !n fill 9 ! re/ ( ! circumf]5ce4 ,if ! arc giv5 is l>ge we c d ?is ) c]ta9ty & accuracy2 b if ! arc is small x is difficult to make q sure ( ! c5tre1 & our draw+ may n be q accurate4 ,n[ ! arc :i* _h be5 describ$ by ! t9y planet dur+ ,piazzi's obs]vations 0 only ?ree degrees2 & if any "o w k9dly take out 8 wat* & look at ! m9ute m>ks r\nd ! dial1 ?ree degrees is j half a s+le m9ute space4 ,if ! re/ ( ! dial 7 oblit]at$1 & only ?is small arc left1 w\ld he feel mu* confid5ce 9 re/or+ ! oblit]at$ portion8 ,?is problem gives "s idea ( ! difficulties to be enc\nt]$1 b only ev5 !n a v imp]fect "o4 ,sid5ote3 ,gauss %[s h[ to f9d x4 ,briefly1 ! solution dem&$ a new ma!matical me?od 9 a/ronomy4 ,b difficulties are sometimes ! opportunities ( great m51 & ?is p>ticul> difficulty attract$ to a/ronomy ! great ma!matician ,gauss1 :o set himself to make ! be/ ( ! obs]vation available1 & produc$ 8 classical "w1 ! ,!oria ,motus1 :i* is ! /&>d "w = su* calculations to ! pres5t day4 ,may we look = a few mom5ts at :at he himself says 9 ! preface to 8 great "w8 ,i v5ture to reproduce ! foll[+ r\gh translation 7! book be+ writt5 9 ,lat91 accord+ to ! sci5tific usage ( ! "t73-- ,,extract ,,f ,,! ,,preface ,,to ,,! ,!oria ,motus4 ,sid5ote3 ,! ,!oria ,motus4 ,"s ideas _h occurr$ to me on ?is subject 9 ,septemb] #ahja1 at a "t :5 ,i 0 occupi$ on some?+ q diff]5t2 ideas :i* seem$ to contribute to ! solution ( ! great problem ( :i* ,i h spok54 ,9 su* cases x (t5 happ5s t1 le/ we be too mu* ,di/ract$ ,f ! ,attractive ,inve/igation ,on ,:i* ,we ,are ,engag$1 ,we ,all[ ,associations ,( ,ideas ,:i*1 ,if ,m ,closely ,exam9$1 ,might ,prove ,extraord9>ily ,fruitful1 ,to ,p]i% ,f ,neglect4 ,p]*ance ,^! ,same ,idea-lets ( ,m9e ,w\ld ,h ,met ,) ,?is ,fate1 ,if ,!y ,_h ,n ,mo/ ,=tunately ,light$ ,^u a ,"t ,?an ,:i* ,none ,c\ld ,h ,be5 ,*os5 ,m ,fav\rable ,= ,_! ,pres]vation & ,developm5t4 ,= ,ab\t ,! ,same ,"t a ,rum\r ,began ,to ,be ,spread ,abroad ,conc]n+ a ,new ,planet ,:i* ,_h ,be5 ,detect$ ,on ,janu>y #a/ ( ,t ,ye> at ! ,obs]vatory ,( ,pal]mo2 & ,%ortly ,aft]w>ds ! ,actual ,obs]vations ,:i* ,_h ,be5 ,made ,betwe5 ,janu>y #a/ ,& ,febru>y #aa? by ! ,r5[n$ ,philosoph] ,piazzi ,7 ,publi%$4 ,n[h]e 9 ,all ,! ,annals ( ,a/ronomy ,d ,we ,f9d ,su* an ,important ,occasion2 & ,sc>cely ,is ,x ,possible ,to ,imag9e a ,m ,important ,opportunity = ,po9t+ ,out1 ,z ,emphatically ,z ,possible1 ! ,importance ,( ,t ,problem1 ,z at ! ,mom5t ,:5 ,e ,hope ( ,re-discov]+1 ,among ! ,innum]able ,little ,/>s ( ,heav51 ,t ,mite ( a ,planet ,:i* ,_h ,be5 ,lo/ ,to ,sight = ,ne>ly a ,ye>1 ,dep5d$ ,entirely on an ,approximate ,k ,( ,its ,orbit1 ,:i* ,mu/ ,be ,d$uc$ ,f ,^? ,scanty ,obs]vations4 ,c\ld ,i ,ev] ,h ,_h ,a ,bett] ,opportunity = ,try+ ,:e!r ,^? ,idea-lets ,( ,m9e ,7 ( ,any ,practical ,value ,?an ,if ,i ,!n ,7 ,to ,use ,!m = ! ,det]m9ation ,( ,! ,orbit ( ,c]es1 a ,planet ,:i*1 9 ! ,c\rse ( ^? =ty-"o days1 _h describ$ ar\nd ! e>? an arc ( no m ?an ?ree degrees8 &1 aft] a ye> _h pass$1 requir$ to be track$ out 9 a region ( ! sky f> remov$ f its orig9al position8 ,! fir/ application ( ?is me?od 0 made 9 ! mon? ( ,octob] #ahja1 & ! fir/ cle> night1 :5 ! planet 0 look$ = by ! help ( ! ephem]is ,i _h made1 reveal$ ! truant to ! obs]v]4 ,?ree new planets f\nd s9ce !n h suppli$ fre% opportunities = exam9+ & prov+ ! efficacy & univ]sality ( ?is me?od4 ,n[ a good _m a/ronom]s1 imm$iately aft] ! r$iscov]y ( ,c]es1 desir$ me to publi% ! me?ods :i* _h be5 us$ 9 my calculations4 ,!re 71 h[ev]1 n a few objections :i* prev5t$ me f gratify+ at t mom5t ^! fri5dly solicitations1 viz4 o!r bus9ess1 ! desire ( treat+ ! matt] m fully1 & m especially ! expectation t1 by cont9u+ to devote myself to ?is rese>*1 ,i %\ld br+ ! diff]5t portions ( ! solution ( ! problem to a m p]fect pit* ( univ]sality1 simplicity1 & elegance4 ,z my hopes h be5 ju/ifi$1 ,i d n ?9k !re is any reason = rep5t+ ( my delay4 ,= ! me?ods :i* ,i _h repeat$ly appli$ f ! beg9n+ admitt$ ( s _m & su* important v>iations1 t sc>cely a ve/ige ( resemblance rema9s betwe5 ! me?od by :i* =m]ly ,i _h arriv$ at ! orbit ( ,c]es & ! practice :i* ,i deal ) 9 ?is "w4 ,al?\gh inde$ x w\ld be ali5 to my int5tion to write a complete hi/ory ab\t all ^! rese>*es :i* ,i h gradually br\ght to ev5 great] p]fection1 yet on _m occasions1 especially :5ev] ,i 0 confront$ by "s p>ticul>ly s]i\s problem1 ,i ?\ght t ! fir/ me?ods :i* ,i employ$ ought n to be entirely suppress$4 ,nay1 r1 9 addition to ! solutions ( ! pr9cipal problems1 ,i h 9 ?is "w foll[$ out _m que/ions :i* pres5t$ !mselves to me1 9 ! c\rse ( a long /udy ( ! motions ( ! heav5ly bodies 9 conic sections1 z be+ p>ticul>ly wor?y ( att5tion1 :e!r on acc\nt ( ! neatness ( ! analysis1 or m especially by reason ( _! practical utility4 ,yet ,i h always giv5 ! great] c>e to subjects :i* ,i h made my own1 m]ely notic+ by ! way well-kn[n facts :]e connection ( ?\ght seem$ to dem& x4 ,sid5ote3 ,r$iscov]y ( ,c]es4 ,sid5ote3 ,ano!r planet f\nd4 ,^! words d n expla9 9 any way ! me?ods introduc$ by ,gauss1 b !y give u "s notion ( ! flav\r ( ! "w4 ,aid$ by ^! brilliant rese>*es1 ! little planet 0 f\nd on ! la/ day ( ! ye> by ,von ,za* at ,go?a1 & on ! next night1 indep5d5tly1 by ,olb]s at ,brem54 ,b1 be=e ?is success1 !re _h be5 an ardu\s se>*1 :i* l$ to a curi\s consequ5ce4 ,olb]s _h made himself s famili> ) all ! small />s along ! track :i* 0 be+ se>*$ = ! miss+ body1 t he 0 at once /ruck by ! appe>ance ( a /rang] ne> ! spot :]e he _h j id5tifi$ ,c]es4 ,at fir/ he ?\ght ?is mu/ be "s /> :i* _h blaz$ up to brightness2 b he soon f\nd t x also 0 mov+1 &1 to ! great bewild]m5t ( ! a/ronomical _w1 x prov$ to be ano!r planet revolv+ r\nd ! sun at a di/ance ne>ly ! same z ! =m]4 ,?is 0 an extraord9>y & totally un=ese5 occurr5ce4 ,! _w _h be5 prep>$ = "o planet2 b "h 7 two6 ,sid5ote3 ,hypo!sis ( _m fragm5ts4 ,! ?\ght occurr$ to ,olb]s t !y 7 p]haps fragm5ts ( a s+le body :i* _h be5 bl[n to pieces by "s explosion1 & t !re might be m ( ! pieces2 & he !re=e sugge/$ z a guide = f9d+ o!rs t1 s9ce by ! kn[n laws ( gravitation1 bodies :i* circle r\nd ! sun return p]iodically to _! />t+-po9t1 !re=e all ^! fragm5ts w\ld 9 due c\rse return to ! po9t 9 ! heav5s :]e ! orig9al planet _h explod$4 ,h5ce ! se>* might be mo/ pr(itably conduct$ 9 ! neighb\rhood ( ! spot :]e ! two fir/ fragm5ts 7:i* _h be5 nam$ ,c]es & ,pallas7 _h already be5 f\nd4 ,we n[ h good reason to believe t ?is view is a mi/ak5 "o1 b nev]!less x 0 app>5tly confirm$ by ! discov]y ( two m bodies ( ! same k9d1 :i* 7 call$ ,juno & ,ve/a2 ! second ( ^! be+ f\nd by ,olb]s himself aft] ?ree ye>s' pati5t "w 9 #ahjg4 ,h5ce1 al?\gh ! idea ( se>*+ = a m or less def9itely imag9$ planet 0 n new1 al?\gh ,bode _h conceiv$ x z e>ly z #aghe1 & organis$ a se>* on ?is plan1 ?ree planets 7 actually f\nd be=e ! fir/ success att5d+ a def9ite se>*4 ,c]es1 z already rem>k$1 0 f\nd by a pure accid5t2 & ! same may be said ( ,pallas & ,juno1 ?\gh x may fairly be add$ t ,pallas 0 actually contr>y to expectation4 ,,m9or ,,planets1 #ahja ,,to #ahej4 --------------------------------------- ,numb] ,"n4 ,discov]]4 ,date4 --------------------------------------- #a ,c]es ,piazzi #ahja #b ,pallas ,olb]s #ahjb #c ,juno ,h>d+ #ahjd #d ,ve/a ,olb]s #ahjg ------------------------------------ #e ,a/raea ,h5cke #ahde #f ,hebe ,h5cke #ahdg #g ,iris ,h9d #ahdg #h ,flora ,h9d #ahdg #i ,metis ,graham #ahdh #aj ,hygeia ,de ,gasp>is #ahdi #aa ,p>!nope ,de ,gasp>is #ahej #ab ,victoria ,h9d #ahej #ac ,eg]ia ,de ,gasp>is #ahej --------------------------------------- ,sid5ote3 ,h5cke's long se>*4 ,"h n[ is a table %[+ h[ o!r bodies 7 gradually add$ to ?is fir/ li/ ( f\r1 b y w see t no addition 0 made = a long "t4 ,n t ! se>* 0 imm$iately ab&on$2 b be+ rew>d$ by no success = "s ye>s1 x 0 gradually dropp$1 & ! belief ga9$ gr\nd t ! numb] ( ! planets 0 at la/ complete4 ,! discov]]s ( ,uranus & ( ^! fir/ f\r m9or planets all di$ be=e any fur!r addition 0 made2 & x 0 n until ! end ( #ahde t ,a/raea 0 f\nd by an ex-po/ma/] ( ! ,prussian t[n ( ,driess51 by "n ,h5cke1 :o1 9 spite ( ! g5]al disbelief 9 ! exi/5ce ( any m planets1 set himself dilig5tly to se>* = !m1 & toil$ = fifte5 long ye>s be=e at l5g? reap+ 8 rew>d4 ,o!rs !n resum$ ! se>*2 ,h9d1 ! obs]v] ( an ,engli% amateur a/ronom] ne> ,london1 f\nd ,iris a few weeks aft] ,h5cke _h be5 rew>d$ by a second discov]y 9 #ahdg1 & 9 ! foll[+ ye> ,mr4 ,graham at ,m>kree 9 ,irel& 7:o is /ill liv+1 & has only j retir$ f active "w at ! ,cambridge ,obs]vatory7 f\nd ,metis2 & f t "t new discov]ies h be5 add$ ye> by ye>1 until ! numb] ( planets n[ kn[n exce$s #ejj1 & is /eadily increas+4 ,illu/ration3 ,by p]mission ( ,messrs4 ,macmillan ,co4 ,i4--,j4 ,c4 ,,adams4 ,illu/ration3 ,,ii4--,a4 ,,graham4 ,,discov]] ,,( ,,! ,,n9? ,,m9or ,,planet 7,,metis74 ,sid5ote3 ,! photographic me?od4 ,y w see ! great v>iety *>act]is+ ^! discov]ies2 "s ( !m are ! result ( delib]ate se>*1 o!rs h come accid5tally1 & "s ev5 contr>y to expectation4 ,( ! great majority ( ! e>li] ones x may be said t enorm\s dilig5ce 0 requir$ = ea* discov]y2 to id5tify a planet x is necess>y to h ei!r a good map ( ! />s or to "k !m ?or\ghly1 s t ! map practically exi/s 9 ! bra94 ,we ne$ only rememb] ,h5cke's fifte5 ye>s ( se>* be=e success to recognise :at va/ /ores ( pati5ce & dilig5ce 7 requir$ 9 c>ry+ out ! se>*4 ,b ( late ye>s photography has effect$ a great revolution 9 ?is respect4 ,x is no long] necess>y to d m ?an set :at ,sir ,rob]t ,ball has call$ a />-trap1 or r planet-trap4 ,if a photograph be tak5 ( a region ( ! heav5s1 by ! me?ods famili> to a/ronom]s1 s t ea* /> makes a r\nd dot on ! photographic plate1 any suffici5tly bright object mov+ relatively to ! />s w make a small l9e or trail1 & ?us betray its planet>y "*4 ,9 ?is way mo/ ( ! rec5t discov]ies h be5 made1 & al?\gh dilig5ce is /ill requir$ 9 tak+ ! photographs1 & aga9 9 id5tify+ ! objects ?us f\nd 7:i* are n[ v (t5 ! images ( already kn[n memb]s ( ! sy/em71 ! t$i\s scrut9y ) ! eye has become a ?+ ( ! pa/4 ,,table ,,%[+ ,,! ,,numb] ,,( ,,m9or ,,planets ,,discov]$ ,,9 ,,ea* ,,decade ,,s9ce #ahej4 #ahja to #ahej--;altoge!r #ac discov]ies4 #ahea to #ahfj-- #di #ahfa to #ahgj-- #di #ahga to #ahhj-- #ajh #ahha to #ahij-- #hc #ahia to #aijj-- #ahj ann\ncem5ts ,9 #aija #cf #aijb #ej #aijc #da --- ,total #fji ,n4,b4--,_m ( ! m rec5t ann\ncem5ts turn$ out to ref] to old discov]ies4 ,sid5ote3 ,sc>city ( names4 ,! kn[n numb] ( ^! bodies has accord+ly increas$ s rapidly z to become almo/ an emb>rassm5t2 & 9 "o respect ! emb>rassm5t is def9ite1 = x has become q difficult to f9d names = ! new discov]ies4 ,we rememb] ) amusem5t at ! pres5t "t t = ! e>ly discov]ies !re 0 sometimes a controv]sy 7( ! same k9d z 9 ! case ( ,uranus7 ab\t ! exact "n :i* a planet %\ld h4 ,?us :5 x 0 propos$ to call ,no4 #ab 7discov]$ 9 #ahej1 9 ,london1 by ,mr4 ,h9d7 ,victoria1 !re 0 an outcry by =eign a/ronom]s t by a subt]fuge ! "n ( a reign+ mon>* 0 aga9 be+ propos$ = a planet1 & consid]able opposition 0 manife/$1 especially 9 ,am]ica4 ,b x became cle>1 z o!r discov]ies 7 add$1 t ! li/ ( goddesses1 or ev5 humbl] my?ological p1 w\ld n be l>ge en\gh to g r\nd if we 7 s sev]ely critical1 & mu/ soon] or lat] be supplem5t$ f s\rces hi!rto consid]$ unsuitable2 s1 ultimately1 ! opposition to ! "n ,victoria 0 )drawn4 ,lat] /ill ! re/riction to fem99e names has be5 brok5 ?r\gh2 "o planet has be5 nam$ ,endymion1 & ano!r1 ( :i* we %all pres5tly speak m p>ticul>ly1 has be5 call$ ,eros4 ,b be=e pass+ to him y may c>e to look at "s ( ! names select$ = o!rs3-- ,no4 ,"n4 #bdh ,lameia #bej ,bett9a #bfa ,prymno #bfd ,libussa #bif ,phaetusa #cdj ,edu>da #cda ,cali=nia #cej ,ornam5ta #ceg ,n99a #che ,ilmat> #chi ,indu/ria #cia ,+eborg #dcc ,eros #ddc ,photographica #deg ,allegh5ia #dfb ,eriphyla #dge ,ocllo #dhd ,pittsburghia #ejc ,evelyn ,sid5ote3 ,bett9a4 ,sid5ote3 ,! provisional lett]s4 ,9 connection ) ,no4 #bej !re is an int]e/+ little hi/ory4 ,9 ! ,obs]vatory = #ahhe1 page #fc1 appe>$ ! foll[+ adv]tisem5t3--,h]r ,palisa be+ desir\s to raise funds = 8 int5d$ exp$ition to obs]ve ! ,total ,sol> ,eclipse ( ,augu/ #ahhf1 w sell ! "r ( nam+ ! m9or planet ,no4 #bdd = ,l#ej4 ,! bright idea seems to h /ruck ,h]r ,palisa1 :o _h already discov]$ _m planets & begun to f9d difficulties 9 assign+ suitable names1 t he might turn 8 difficulty into a s\rce ( pr(it 9 a good cause4 ,! (f] 0 n respond$ to imm$iately1 nor until ,h]r ,palisa _h discov]$ two m planets1 ,nos4 #bdh & #bej4 ,he f\nd names = two1 leav+1 h[ev]1 ! la/ discov]$ always op5 = a patron1 & on page #adb ( ! same magaz9e = #ahhf ! foll[+ note in=ms u h[ 8 pati5ce 0 ultimately rew>d$3--,m9or planet ,no4 #bej has be5 nam$ ',bett9a' by ,b>on ,alb]t de ,ro?s*ild4 ,i h n he>d1 h[ev]1 t ?is prec$5t has be5 foll[$ 9 o!r cases1 & ! +5uity ( discov]]s 0 s mu* ov]tax$ t[>ds ! end ( la/ c5tury t ! nam+ ( _! planets fell into arre>s4 ,rec5tly a ,commission1 :i* has be5 e/abli%$ to look aft] ^! small bodies g5]ally1 issu$ a notice t unless ! nam+ 0 accompli%$ be=e a c]ta9 date x w\ld be ru?lessly tak5 out ( ! h&s ( ! neglig5t discov]]s4 ,p]haps we may notice1 be=e pass+ on1 ! provisional sy/em :i* 0 adopt$ to fill up ! int]val requir$ = f9d+ a suitable "n1 & requir$ also = mak+ sure t ! planet 0 9 fact a new "o1 & n m]ely an old "o r$iscov]$4 ,!re 0 a sy/em ( numb]+ 9 exi/5ce z well z ( nam+1 b x 0 unadvisable to atta* ev5 a numb] to a planet until x 0 q c]ta9 t ! discov]y 0 new1 = o!rwise !re might be gaps creat$ 9 :at %\ld be a cont9u\s s]ies by spuri\s discov]ies be+ /ruck out4 ,accord+ly x 0 decid$ to atta* at fir/ to ! object m]ely a lett] ( ! alphabet1 ) ! ye> ( discov]y1 z a provisional "n4 ,! alphabet 01 h[ev]1 run ?r\gh s quickly1 & confusion 0 s likely to ensue if x 0 m]ely repeat$1 t on recomm5c+ x ! lett] ,a 0 prefix$1 & ! symbols adopt$ 7 !re=e ,,aa1 ,,ab1 ,,ac1 c42 aft] complet+ ! alphabet aga91 ! lett] ,b 0 prefix$1 & s on2 & a/ronom]s began to fe> t !y _h be=e !m a monoton\s prospect ( cont9ually add+ new planets1 v>i$ by no incid5t m excit+ ?an />t+ ! alphabet ov] aga9 aft] e score4 ,sid5ote3 ,eros4 ,=tunately1 h[ev]1 on runn+ ?r\gh x = ! fif? "t1 an object ( p>ticul> int]e/ 0 discov]$4 ,mo/ ( ^! bodies revolve at a di/ance f ! sun int]m$iate betwe5 t ( ,m>s & t ( ,jupit]1 b ! little planet :i* took ! symbol ,,dq1 & aft]w>ds ! "n ( ,eros1 0 f\nd to h a mean di/ance actually less ?an t ( ,m>s1 & ?is gave x an extraord9>y importance ) respect to ! great problem ( det]m9+ ! sun's di/ance4 ,to expla9 ?is importance we mu/ make a small digression4 ,sid5ote3 ,transit ( ,v5us4 ,ab\t ! middle ( ! la/ c5tury our k ( ! sun's di/ance 0 v r\gh1 z may be se5 f ! table on p4 #cb2 b !re 7 9 prospect two transits ( ,v5us1 9 #ahgd & #ahhb1 & x 0 hop$ t ^! w\ld give opportunities ( a special k9d = ! measurem5t ( ?is important quantity1 :i* lies at ! root ( all our k ( ! exact masses & dim5sions ( n only ! sun1 b ( ! planets z well4 ,illu/ration3 ,,fig4 #a4 ,sid5ote3 ,! ,black ,drop4 ,! me?od may be briefly summ>is$ ?us3 ,an obs]v] 9 "o "p ( ! e>? w\ld see ,v5us cross ! disc ( ! sun along a diff]5t pa? f t se5 by ano!r obs]v]1 z w be cle> f ! diagram4 ,if ! size ( ! e>?1 ! di/ance ( ! sun1 & ! relative di/ance ( ,v5us be kn[n1 x c be calculat$ :at ?is diff]5ce 9 pa? w be4 ,n[ ! relative di/ance ( ,v5us is kn[n ) great accuracy1 f obs]v+ ! "t ( h] revolution r\nd ! sun2 ! size ( ! e>? we c measure by a survey2 !re rema9s1 !re=e1 only "o unkn[n quantity1 ! sun's di/ance4 ,& s9ce f a k ( ?is we c\ld calculate ! diff]5ce 9 pa?1 x is easy to inv]t ! problem1 & calculate ! sun's di/ance f ! k ( ! obs]v$ diff]5ce 9 pa?4 ,accord+ly1 obs]v]s 7 to be scatt]$1 n m]ely to two1 b to _m /ations ov] ! face ( ! e>?1 to obs]ve ! exact pa? tak5 by ,v5us 9 transit ov] ! sun's disc z se5 f _! /ation2 & especially to obs]ve ! exact times ( beg9n+ & end+ ( ! transit2 &1 by comp>ison ( _! results1 x 0 hop$ to det]m9e ?is v important quantity1 ! sun's di/ance4 ,x 0 kn[n f previ\s exp]i5ce t !re 7 c]ta9 difficulties 9 obs]v+ v exactly ! beg9n+ & end ( ! transit4 ,!re 0 an appe>ance call$ ! ,black ,drop1 :i* _h caus$ tr\ble on previ\s occasions2 an appe>ance z ?\gh ! r\nd black spot :i* c be se5 :5 ,v5us has advanc$ "s di/ance ov] ! sun's disc 0 reluctant to make ! entry & clung to ! edge or limb ( ! sun z x is call$1 some:at z a drop ( ink cl+s to a p5 :i* is sl[ly )drawn f an inkpot4 ,simil>ly1 at ! end ( ! transit or egress1 in/ead ( approa*+ ! limb /eadily ! planet seems at ! la/ mom5t to bur/ out t[>ds x1 r5d]+ ! e/imation ( ! exact mom5t :5 ! transit is ov] extremely d\btful4 ,sid5ote3 ,failure4 ,^! difficulties1 z already /at$1 7 kn[n to exi/2 b !re is a long int]val betwe5 transits ( ,v5us1 or r betwe5 e pair ( su* transits4 ,aft] ^? ( #ahgd & #ahhb !re w be no m until #bjjd & #bjab1 s t we %all nev] see ano!r2 simil>ly1 be=e t pair ( ! la/ c5tury1 !re _h n be5 any su* occasion s9ce #agfa & #agfi1 & no "o 0 alive :o rememb]$ at fir/ h& ! tr\ble :i* 0 kn[n to exi/4 ,x 0 propos$ to obviate ! anticipat$ difficulties by c>eful practice be=eh&2 models 7 prep>$ to resemble z ne>ly z possible ! expect$ appe>ances1 & ! times record$ by diff]5t obs]v]s 7 comp>$ ) ! true "t1 :i* c\ld1 9 ?is case ( a model1 be det]m9$4 ,9 ?is way x 0 hop$ t ! habit ( ea* obs]v]1 8 p]sonal equation z x is call$1 c\ld be det]m9$ be=eh&1 & all[$ = z a correction :5 he came to obs]ve ! actual transit4 ,! result1 h[ev]1 0 a great disappo9tm5t4 ,! actual appe>ances 7 f\nd to be totally diff]5t 9 "* f ^? %[n by ! model2 *iefly1 p]haps1 because x _h be5 impossible to imitate ) a model ! effect ( ! atmosph]e :i* surr\nds ! planet ,v5us4 ,obs]v]s tra9$ be=eh&1 us+ simil> in/rum5ts1 & /&+ )9 a few feet ( ea* o!r1 7 expect$1 aft] mak+ due all[ance = p]sonal equation1 to give ! same in/ant = contact2 b _! obs]vations :5 made 7 f\nd to diff] by ne>ly a m9ute ( "t1 & aft] an exhau/ive review ( ! :ole mat]ial x 0 felt t all hope ( det]m9+ accurately ! sun's di/ance by ?is me?od mu/ be giv5 up4 ,! foll[+ table w %[ h[ mu* 0 le>n$ f ! transits ( ,v5us1 & h[ mu* rema9$ to be settl$4 ,!y left ! result 9 d\bt ov] a range ( ab\t two million miles4 ,,sun',s ,,di/ance1 ,,9 ,,millions ,,( ,,miles1 ,,z ,,f\nd ,,by ,,diff]5t ,,obs]v]s ,be=e ! ,transits ( ,v5us e/imates v>i$ betwe5 #if million miles 7,gilliss & ,g\ld1 #ahef7 & #ia million 7,w9ne*e1 #ahfc71 a range ( #e million miles4 ,! ,transits ( #ahgd & #ahhb gave results ly+ betwe5 #ic-a_/d million 7,airy1 f ,briti% obs]vations ( #ahgd71 #ib-a_/b million 7,/one1 f ,briti% obs]vations ( #ahhb71 & #ia-a_/b million 7,puiseux1 f ,fr5* obs]vations71 a range ( #a-c_/d millions4 ,gill's ,heliomet] results all lie v ne> #ic millions4 ,! obs]vations ( ,m>s 9 #ahgg give ab\t #ajj1jjj miles ov] ?is figure3 b ! obs]vations ( ,victoria1 ,iris1 & ,sappho1 :i* are m tru/wor?y1 all agree 9 giv+ ab\t #ajj1jjj miles less ?an ! #ic millions4 ,x became necess>y1 !re=e1 to look to o!r me?ods2 & be=e ! second transit ( #ahhb 0 obs]v$1 an en]getic a/ronom]1 ,dr4 ,david ,gill1 _h already put into op]ation ! me?od :i* may be n[ reg>d$ z ! /&>d "o4 ,sid5ote3 ,mod]n me?od = sun's di/ance4 ,sid5ote3 ,photography4 ,sid5ote3 ,dr4 ,gill's exp$ition to ,asc5sion4 ,we h said t ! relative di/ance ( ,v5us f ! sun is accurately kn[n f obs]vations ( ! exact "t ( revolution4 ,x is easy to see t ^! times ( revolution c be measur$ accurately by m]e accumulation4 ,we may make an error ( a few seconds 9 not+ ! "t ( return2 b if ! :ole int]val comprises #aj revolutions1 ?is error is divid$ by #aj1 if #ajj revolutions by #ajj1 & s on2 & by ?is "t a great numb] ( revolutions ( all ! planets 7except ^? j discov]$7 h be5 record$4 ,h5ce we "k _! relative di/ances ) great precision2 & if we c f9d ! di/ance 9 miles ( any "o ( !m1 we c f9d t ( ! sun itself1 or ( any o!r planet1 by a simple rule-(-?ree sum4 ,by mak+ use ( ?is pr9ciple _m ( ! difficulties att5d+ ! direct det]m9ation ( ! sun's di/ance c be avoid$2 = in/ance1 s9ce ! sun's light ov]p[]s t ( ! />s1 x is n easy to directly obs]ve ! place ( ! sun among ! />s2 b ?is is n s = ! planets4 ,we c photograph a planet & ! />s surr\nd+ x on ! same plate1 & !n by c>eful measurem5t det]m9e its exact position among ! />s2 & s9ce ?is position diff]s slightly accord+ to ! situation ( ! obs]v] on ! e>?'s surface1 by comp>+ two photographs tak5 at /ations a kn[n di/ance ap>t we c f9d ! di/ance ( ! planet f ! e>?2 & h5ce1 z above rem>k$1 ! di/ance ( ! sun & all ! o!r memb]s ( ! sol> sy/em4 ,or1 in/ead ( tak+ photographs f two diff]5t /ations1 we c take f ! same /ation two photographs at times sep>at$ by a kn[n int]val4 ,= 9 t int]val ! /ation w h be5 c>ri$ by ! e>?'s rotation "s ?\s&s ( miles away f its =m] position1 & becomes virtually a second /ation sep>at$ f ! fir/ by a di/ance :i* is kn[n accurately :5 we "k ! elaps$ "t4 ,aga91 in/ead ( tak+ photographs1 & f !m measur+ ! position ( ! planet among ! />s1 we may make ! measurem5ts on ! planet & />s 9 ! sky itself2 & s9ce 9 #ahgh1 :5 ,dr4 ,gill set out on 8 ent]prise ( det]m9+ ! sun's di/ance1 photography 0 9 its infancy z appli$ to a/ronomy1 he naturally made 8 obs]vations on ! sky ) an in/rum5t kn[n z a heliomet]4 ,he made !m 9 ! little isl& ( ,asc5sion1 :i* is suitably situat$ = ! purpose2 because1 be+ ne> ! e>?'s equator1 x is c>ri$ by ! e>?'s rotation a long] di/ance 9 a giv5 "t ?an places ne>] ! poles1 & 9 ^! obs]vations = p>allax1 z !y are call$1 x is important to h ! displacem5t ( ! /ation z l>ge z possible4 ,= a simil> reason ! object select$ among ! planets mu/ be z ne> ! e>? z possible2 & h5ce ! planet ,m>s1 :i* at fav\rable times comes ne>] to u ?an any o!r sup]ior planet#a !n kn[n1 0 select$ = obs]vation ) ! heliomet]4 ,& n[ x w be se5 :y ! discov]y ( ! little planet ,eros 0 important1 = ,m>s 0 no long] ! kn[n planet capable ( com+ ne>e/ to u2 x _h be5 replac$ by ?is new arrival4 ,sid5ote3 ,victoria1 ,iris1 & ,sappho4 ,sid5ote3 ,eros4 ,fur!r1 a small planet :i* is 9 appe>ance j l an ord9>y /> has1 irrespective ( ?is great proximity1 "s di/9ct advantages ov] a planet l ,m>s1 :i* appe>s z a r\nd disc1 & is1 moreov]1 ( a some:at r$di% col\r4 ,:5 ! di/ance ( an object ( ?is k9d f a po9t ( l9e su* z a /> is measur$ ) ! heliomet] x is f\nd t a c]ta9 bias1 some:at difficult to all[ = ) c]ta9ty1 is introduc$ into ! measures2 & our confid5ce 9 ! f9al results suff]s accord+ly4 ,aft] 8 obs]vations ( ,m>s 9 #ahgh1 ,dr4 ,david ,gill 0 suffici5tly impress$ ) ?is s\rce ( error to make ?ree new det]m9ations ( ! sun's di/ance1 us+ ?ree ( ! m9or planets in/ead ( ,m>s1 9 spite ( ! fact t !y 7 s5sibly f>!r away2 & 8 *oice 0 ju/ifi$ by f9d+ t ! results f ^! ?ree diff]5t sets ( obs]vations agre$ well among !mselves1 & diff]$ slightly f t giv5 by ! obs]vations ( ,m>s4 ,h5ce x seems conclusively prov$ t "o ( ^! bodies is a bett] selection ?an ,m>s 9 any case1 & ! discov]y ( ,eros1 :i* (f]$ ! advantage ( great] proximity 9 addition1 0 hail$ z a new opportunity ( a mo/ welcome k9d4 ,x 0 se5 by a little calculation t 9 ! w9t] ( #aijj-aija ! planet w\ld come v ne> ! e>?2 n ! ne>e/ possible 7= x 0 also realis$ t a /ill bett] opportunity _h occurr$ 9 #ahid1 ?\gh x 0 lo/ because ! planet _h n yet be5 discov]$71 b /ill ! ne>e/ approa* :i* w\ld occur = "s ?irty ye>s2 & ext5sive1 ?\gh some:at ha/y1 prep>ations 7 made to use x to ! fulle/ advantage4 ,photography _h n[ become e/abli%$ z an accurate me?od ( mak+ measurem5ts ( ! k9d requir$2 & all ! photographic telescopes :i* c\ld be sp>$ 7 press$ into ! s]vice1 & dilig5tly photograph$ ! planet & surr\nd+ />s e f9e night dur+ ! fav\rable p]iod4 ,! "w ( measur+ & r$uc+ ^! photographs involves an enorm\s am\nt ( lab\r1 & is ev5 yet f> f complet$1 b we "k en\gh to expect a result ( ! greate/ value4 ,m ?an ?is we h n "t to say "h ab\t ?is great problem1 b x w h be5 made cle> t j :5 a/ronom]s 7 beg9n+ to wond] :e!r x 0 wor? :ile cont9u+ ! monoton\s discov]y ( new m9or planets by ! h&ful1 ! #dccrd discov]y also turn$ out to be "o ( ! greate/ importance4 ,to canons = ! advantage\s prosecution ( rese>*1 if we c>e to make !m1 we may !re=e add ?is--t !re is no l9e ( rese>*1 h[ev] app>5tly unimportant or monoton\s1 :i* we c af=d to neglect4 ,j :5 we are on ! po9t ( rel9qui%+ x "u ! impression t ! m9e is exhau/$1 we may be ab\t to f9d a nugget wor? all our previ\s & future lab\r4 ,?is rule w n1 p]haps1 help u v mu* 9 *oos+ :at to "w at2 inde$1 x is no rule at all1 = x leaves u ! :ole field ( *oice unlimit$4 ,b ?is negative result w recur aga9 & aga9 z we exam9e ! lessons taught by discov]ies3 !re seem to be no rules at all4 ,:5ev] we seem to be able to d$uce "o f an exp]i5ce1 "s o!r exp]i5ce w flatly contradict x4 ,?us we might ?9k t ! discov]y ( ,eros taught u to proce$ pati5tly ) a monoton\s duty1 & n turn aside to m novel & attractive "w2 yet x is (t5 by leav+ :at is 9 h& & app>5tly has fir/ claim on our att5tion t we %all d be/1 & we %all le>n 9 ! next *apt] h[ a failure ?us to turn flexibly aside 0 rep5t$4 ,,*apt] ,,ii ,,! ,,discov]y ,,( ,,neptune ,sid5ote3 ,se>* = def9ite objects4 ,9 ! la/ *apt] we saw t ! circum/ances "u :i* planets 7 discov]$ v>i$ consid]ably4 ,sometimes ! discov]ies 7 n previ\sly expect$1 occurr+ dur+ a g5]al exam9ation ( ! heav5s1 or a se>* = o!r objects2 &1 on "o occasion at lea/1 ! discov]y may be said to h be5 ev5 contr>y to expectation1 ?\gh1 z ! exi/5ce ( a numb] ( m9or planets began to be realis$1 !re h also be5 _m cases :]e ! discov]y has be5 made z ! result ( a def9ite & delib]ate se>*4 ,b ! se>* _c be said to h be5 inspir$ by any v cle> or c]ta9 pr9ciple3 = ! law ( ,bode1 successful ?\gh x has be5 9 indicat+ ! possible exi/5ce ( new planets1 _c1 z yet1 be said to be f\nd$ ^u a =mulat$ law ( nature4 ,we n[ come1 h[ev]1 to a discov]y made 9 direct int]pretation ( ,newton's great law ( gravitation--! discov]y ( ,neptune f its obs]v$ di/urbance ( ,uranus4 ,i w fir/ briefly recall ! ma9 facts relat+ to ! actual discov]y4 ,sid5ote3 ,di/urbance ( ,uranus4 ,aft] ,uranus _h be5 discov]$ & obs]v$ suffici5tly long = its orbit to be calculat$1 x 0 f\nd t ! subsequ5t position ( ! planet did n always agree ) ?is orbit2 &1 m s]i\s ?an ?is1 "s e>ly obs]vations 7 f\nd :i* c\ld n be reconcil$ ) ! lat] ones at all4 ,x is a wond]ful te/imony to ! c>e & sagacity ( ,sir ,william ,h]s*el1 z 0 rem>k$ 9 ! la/ *apt]1 t ,uranus 0 f\nd to h be5 obs]v$1 "u ! mi/ak5 impression t x 0 an ord9>y />1 by ,flam/e$1 ,lemonni]1 ,bradley1 & ,may]1 all obs]v]s ( consid]able ability4 ,flam/e$'s five obs]vations dat$ z f> back z #afij1 #agab1 & #agae2 obs]vations by o!rs 7 9 #agdh1 #agej1 #agec1 #agef1 & s on up to #agga1 & ! body ( te/imony 0 s consid]able t !re 0 no room = d\bt z to ! irreconcilability ( ! obs]vations ) ! orbit1 su* z might h be5 ! case _h !re be5 only "o or two1 possibly affect$ ) "s errors4 ,sid5ote3 ,suspicion ( p]turb+ planet4 ,x is difficult to m5tion an exact date = ! conv]sion into c]ta9ty ( ! suspicion t no s+le orbit c\ld be f\nd to satisfy all ! obs]vations2 b we may c]ta9ly reg>d ?is fact z e/abli%$ 9 #ahba1 :5 ,alexis ,b\v>d publi%$ "s tables ( ! planet1 & %[$ fully 9 ! introduction t :5 e correction = ! di/urb+ action ( o!r planets _h be5 appli$1 x 0 /ill impossible to reconcile ! old obs]vations ) ! orbit calculat$ f ! new ones4 ,! idea accord+ly grew up t !re might be "s o!r body or bodies attract+ ! planet & caus+ ^! discrepancies4 ,"h aga9 x is n easy to say exactly :5 ?is notion arose1 b x 0 c]ta9ly exi/5t 9 #ahcd1 z ! foll[+ lett] to ! ,a/ronom] ,royal w %[4 ,i take x f 8 well-kn[n ,acc\nt ( "s ,circum/ances hi/orically connect$ ) ! ,discov]y ( ! ,planet ext]ior to ,uranus1 :i* he gave to ! ,royal ,a/ronomical ,society at its fir/ meet+ aft] t fam\s discov]y 7,mon?ly ,notices ( ! ,r4,a4,s41 vol4 iii41 & ,memoirs1 vol4 xvi474 ,,no4 #a4--,! ,,rev4 ,t4 ,j4 ,,hussey to ,g4 ,b4 ,,airy4 ,extract4 ',,hayes1 ,,k5t1 #ag? ,novemb] #ahcd4 ',) ,m4 ,alexis ,b\v>d ,i _h "s conv]sation ^u a subject ,i _h (t5 m$itat$1 :i* w probably int]e/ y1 & y\r op9ion may det]m9e m9e4 ,hav+ tak5 great pa9s la/ ye> ) "s obs]vations ( ,uranus1 ,i 0 l$ to exam9e closely ,b\v>d's tables ( t planet4 ,! app>5tly inexplicable discrepancies betwe5 ! anci5t & mod]n obs]vations sugge/$ to me ! possibility ( "s di/urb+ body beyond ,uranus1 n tak5 into acc\nt because unkn[n4 ,my fir/ idea 0 to asc]ta9 "s approximate place ( ?is suppos$ body empirically1 & !n ) my l>ge reflector set to "w to exam9e all ! m9ute />s !reab\ts3 b ,i f\nd myself totally inadequate to ! =m] "p ( ! task4 ,if ,i c\ld h done x =m]ly1 x 0 beyond me n[1 ev5 suppos+ ,i _h ! "t1 :i* 0 n ! case4 ,i !re=e rel9qui%$ ! matt] altoge!r2 b subsequ5tly1 9 conv]sation ) ,b\v>d1 ,i inquir$ if ! above might n be ! case3 8 answ] 01 t1 z might h be5 expect$1 x _h occurr$ to him1 & "s correspond5ce _h tak5 place betwe5 ,hans5 & himself respect+ x4 ,hans5's op9ion 01 t "o di/urb+ body w\ld n satisfy ! ph5om5a2 b t he conjectur$ !re 7 two planets beyond ,uranus4 ,^u my speak+ ( obta9+ ! places empirically1 & !n sweep+ closely = ! bodies1 he fully acquiesc$ 9 ! propriety ( x1 intimat+ t ! previ\s calculations w\ld be m labori\s ?an difficult2 t if he _h leisure he w\ld und]take !m & transmit ! results to me1 z ! basis ( a v close & accurate sweep4 ,i h n he>d f him s9ce on ! subject1 & h be5 too ill to write4 ,:at is y\r op9ion on ! subject8 ,if y consid] ! idea z possible1 c y give me ! limits1 r\ghly1 betwe5 :i* ?is body or ^? bodies may probably be f\nd dur+ ! ensu+ w9t]8 ,z we might expect an ecc5tricity incl9ation8 approa*+ r to t ( ! old planets ?an ( ! new1 ! bread? ( ! zone to be exam9$ w be comp>atively inconsid]able4 ,i may be wrong1 b ,i am dispos$ to ?9k t1 su* is ! p]fection ( my equatoreal's object-glass1 ,i c\ld di/+ui%1 almo/ at once1 ! diff]5ce ( light ( a small planet & a />4 ,my plan ( proce$+1 h[ev]1 w\ld be v diff]5t3 ,i %\ld accurately map ! :ole space )9 ! requir$ limits1 d[n to ! m9ute/ /> ,i c\ld disc]n2 ! int]val ( a s+le week w\ld !n enable me to asc]ta9 any *ange4 ,if ! :ole ( ?is matt] d n appe> to y a *ima]a1 :i*1 until my conv]sation ) ,b\v>d1 ,i 0 afraid x might1 ,i %all be v glad ( any sort ( h9t respect+ x4' ,my answ] 0 9 ! foll[+ t]ms3-- ,sid5ote3 ,airy's scepticism4 ,,no4 #b4--;,g4 ,b4 ,,airy to ! ,,rev4 ,t4 ,j4 ,,hussey4 ,extract4 ',,obs]vatory1 ,,cambridge1 #ahcd1 ,nov4 #bc4 ',i h (t5 ?\ght ( ! irregul>ity ( ,uranus1 & s9ce ! receipt ( y\r lett] h look$ m c>efully to x4 ,x is a puzzl+ subject1 b ,i give x z my op9ion1 )\t hesitation1 t x is n yet 9 su* a /ate z to give ! smalle/ hope ( mak+ out ! nature ( any ext]nal action on ! planet 444 if x 7 c]ta9 t !re 7 any extrane\s action1 ,i d\bt mu* ! possibility ( det]m9+ ! place ( a planet :i* produc$ x4 ,i am sure x c\ld n be done till ! nature ( ! irregul>ity 0 well det]m9$ f sev]al successive revolutions4' ,sid5ote3 ,le ,v]ri]'s pap]s4 ,sid5ote3 ,planet to be detect$ by disc4 ,sid5ote3 ,galle's discov]y ( ! planet4 ,al?\gh only a s5t5ce or two h be5 select$ f ,airy's reply 7he 0 n yet ,a/ronom] ,royal71 !y are suffici5t to %[ t ! problem ( f9d+ ! place ( su* a possible di/urb+ body 0 reg>d$ at t "t z "o ( extreme difficulty2 & no "o appe>s s]i\sly to h contemplat$ emb>k+ ^u its solution4 ,x 0 n until _m ye>s lat] t ! solution 0 attempt$4 ,( ! fir/ attempt we %all speak pres5tly1 putt+ x aside = ! mom5t because x _h no actual be>+ on ! discov]y ( ! planet1 = reasons :i* =m an extraord9>y episode ( ?is hi/ory4 ,! attempt :i* l$ to success dates f ,novemb] #ahde4 ,! great ,fr5* a/ronom] ,le ,v]ri]1 on ,novemb] #aj1 #ahde1 read to ! ,fr5* ,academy a pap] on ! ,orbit ( ,uranus1 consid]+ specially ! di/urbances produc$ by ,jupit] & ,saturn1 & %[+ cle>ly t ) no possible orbit c\ld ! obs]vations be satisfi$4 ,on ,june #a1 #ahdf1 foll[$ a second pap] by ! same au?or1 9 :i* he consid]s all ! possible explanations ( ! discordance1 & concludes t none is admissible except t ( a di/urb+ planet ext]ior to ,uranus4 ,& assum+1 9 accordance ) ,bode's ,law1 t ! di/ance ( ?is new planet f ! sun w\ld be ab\t d\ble t ( ,uranus 7& x is important to note ?is assumption71 he proce$s to inve/igate ! orbit ( su* a planet1 & to calculate ! place :]e x mu/ be look$ = 9 ! heav5s4 ,?is 0 foll[$ by a ?ird pap] on ,augu/ #ca/1 giv+ a r complet] discussion1 & arriv+ at ! conclusion t ! planet %\ld be recognisable f its disc4 ,?is aga9 is an important po9t4 ,we rememb] t 9 ! discov]y ( ,uranus x ne$$ consid]able skill on ! "p ( ,sir ,william ,h]s*el to detect ! disc1 to see 9 fact any diff]5ce betwe5 x & surr\nd+ />s2 & t o!r obs]v]s1 ev5 :5 _! att5tion _h be5 call$ to ! planet1 f\nd x difficult to see ?is diff]5ce4 ,x might be expect$1 !re=e1 t ) a planet twice z f> away 7z _h be5 assum$ = ! new planet7 ! disc w\ld be practically unrecognisable1 & z we %all pres5tly see1 ?is assumption 0 made 9 "s se>*es = ! planet :i* _h be5 comm5c$ ev5 be=e ! publication ( ?is ?ird pap]4 ,le ,v]ri]'s c\rage\s ann\ncem5t1 :i* he d$uc$ f a consid]ation ( ! mass ( ! planet1 t ! disc %\ld be recognisable1 l$ imm$iately to ! discov]y ( ! suspect$ body4 ,he wrote to a ,g]man a/ronom]1 ,dr4 ,galle 7/ill1 ,i am glad to say1 alive & well1 ?\gh n[ a v old man71 tell+ him ! spot 9 ! heav5s to se>*1 & /at+ t he might expect to detect ! planet by its appe>ance 9 ?is way2 & ! same night ,dr4 ,galle1 by comp>+ a /> map ) ! heav5s1 f\nd ! planet4 ,sid5ote3 ,adams' "w publicly ann\nc$4 ,to two po9ts to :i* ,i h specially call$ att5tion 9 ?is brief summ>y--namely1 ! prelim9>y assumption t ! planet w\ld be1 accord+ to ,bode's ,law1 twice z f> away z ,uranus2 secondly1 ! confid5t ass]tion t x w\ld h a visible disc--,i w ask y to add1 ?irdly1 t x 0 f\nd by ! aid ( a /> map1 = ?is map play$ an important "p 9 ! fur!r hi/ory to :i* we %all n[ proce$4 ,x may naturally be suppos$ t ! ann\ncem5t ( ! f9d+ ( a planet 9 ?is way1 ! calculation ( its place f a belief 9 ! univ]sal action ( ! great ,law ( ,gravitation1 ! direction to an em95t obs]v] to look 9 t place = a p>ticul> ?+1 & 8 imm$iate success1--?is extraord9>y comb9ation ( circum/ances caus$ a pr(\nd s5sation ?r\gh\t n only ! a/ronomical1 b ! :ole _w2 & ?is s5sation 0 greatly enhanc$ by ! rum\r :i* _h begun to ga!r /r5g? t1 b = "s un=tunate circum/ances1 ! discov]y might h be5 made ev5 e>li] & z a consequ5ce ( totally indep5d5t calculations made by a "y ,cambridge ma!matician1 ,j4 ,c4 ,adams4 ,"s ( y are d\btless already famili> ) ! /ory 9 its abridg$ =m1 = x has be5 scatt]$ broadca/ ?r\gh lit]ature4 ,9 ,engl& x g5]ally takes ! =m ( emphasis+ ! wick$ness or laz9ess ( ! ,a/ronom] ,royal :o1 :5 told :]e to look = a planet1 neglect$ 8 obvi\s duty1 s t 9 consequ5ce ano!r a/ronom] :o made ! calculation mu* lat] & gave a m virtu\s obs]v] ! same directions :]e to look1 obta9$ = ,france ! glory ( a discov]y :i* ought to h be5 reta9$ 9 ,engl&4 ,!re is no d\bt t ,airy's conduct receiv$ a l>ge am\nt ( :at he call$ savage abuse4 ,:5 ! facts are cle>ly /at$ ,i ?9k x w be evid5t t _m ( ! h>% ?+s said ( him 7 sc>cely j1 ?\gh at ! same "t x is also difficult to und]/& 8 conduct at two or ?ree po9ts ( ! hi/ory1 ev5 z expla9$ by himself4 ,sid5ote3 ,facts und\bt$4 ,!re is =tunately no d\bt :atev] ab\t any ( ! facts4 ,airy himself gave a v cle> & /raight=w>d acc\nt ( !m at ! "t1 = :i* m cr$it is due to him ?an he commonly receives2 & s9ce ! dea? ( ! *ief actors 9 ?is s5sational drama !y h be5 naturally aga9 ransack$1 ) ! satisfactory result t !re is practically no d\bt ab\t any ( ! facts4 ,z to ! prop] int]pretations ( !m !re c]ta9ly may be wide diff]5ces ( op9ion1 nor does ?is circum/ance detract f _! int]e/4 ,x is almo/ impossible to make a p]fectly col\rless recital ( !m1 nor is x p]haps necess>y to d s4 ,i w !re=e ask y to rememb] 9 :at ,i n[ say t !re is almo/ necess>ily an elem5t ( p]sonal bias1 & t ano!r writ] w\ld probably give a diff]5t col\r+4 ,hav+ said ?is1 ,i hope ,i may speak q freely z ! matt] appe>s 9 my p]sonal e/imation4 ,sid5ote3 ,airy's ,acc\nt4 ,sid5ote3 ,a movem5t ( ! age4 ,airy's acc\nt 01 z above /at$1 giv5 to ! ,royal ,a/ronomical ,society at _! fir/ meet+ 7aft] ! />tl+ ann\ncem5t ( ! discov]y ( ! new planet71 on ,novemb] #ac1 #ahdf1 & ,i h already quot$ an extract f x4 ,he op5s ) a tribute to ! s5sational "* ( ! discov]y1 & !n /ates t al?\gh cle>ly due to two individuals 7namely1 ,le ,v]ri] & ,galle71 x might also be reg>d$ z to "s ext5t ! consequ5ce ( a movem5t ( ! age4 ,8 actual words are ^!3 ,! pr9cipal /eps 9 ! !oretical inve/igations h be5 made by "o individual1 & ! publi%$ discov]y ( ! planet 0 necess>ily made by "o individual4 ,to ^! p]sons ! public att5tion has be5 pr9cipally direct$2 & well d !y des]ve ! hon\rs :i* !y h receiv$1 & :i* !y w cont9ue to receive4 ,yet we %\ld d wrong if we consid]$ t ^! two p]sons alone are to be reg>d$ z ! au?ors ( ! discov]y ( ?is planet4 ,i am confid5t t x w be f\nd t ! discov]y is a consequ5ce ( :at may prop]ly be call$ a movem5t ( ! age2 t x has be5 urg$ by ! feel+ ( ! sci5tific _w 9 g5]al1 & has be5 ne>ly p]fect$ by ! collat]al1 b indep5d5t lab\rs1 ( v>i\s p]sons possess+ ! tal5ts or p[]s be/ suit$ to ! diff]5t p>ts ( ! rese>*es4 ,sid5ote3 ,airy "u-e/imat$ ,adams' "w4 ,i h quot$ ^! words z ! fir/ po9t at :i* x is difficult to und]/& ,airy's conduct 9 exclud+ f !m all specific m5tion ( ,adams1 kn[+ z he did ! special claims :i* entitl$ him to su* m5tion2 claims inde$ :i* he proce$$ imm$iately to make cle>4 ,x seems almo/ c]ta9 t ,airy entirely "u-e/imat$ ! value ( ,adams' "w ?r\gh\t4 ,b ?is w become cle>] z we proce$4 ,! acc\nt takes ! =m ( ! publication ( a s]ies ( lett]s ) occasional comm5ts4 ,airy 0 a mo/ me?odical p]son1 & fil$ all 8 correspond5ce ) great regul>ity4 ,x 0 je/+ly said ( him once t if he wip$ 8 p5 on a piece ( blott+-pap]1 he w\ld date ! blott+-pap] & file x = ref]5ce4 ,! lett]s reproduc$ 9 ?is acc\nt are /ill 9 ! ,obs]vatory at ,gre5wi*1 p9n$ toge!r j z ,airy left !m2 & 9 prep>+ 8 acc\nt x 0 necess>y to d little else ?an to h !m copi$ out & int]polate comm5ts4 ,f two ( !m ,i h already quot$ to %[ h[ difficult ! ent]prise ( f9d+ an ext]ior planet f its action on ,uranus 0 consid]$ 9 #ahcd4 ,to ^! may be add$ ! foll[+ s5t5ce f ,no4 #d1 dat$ #ahcg4 ,if x be ! effect ( any unse5 body1 writes ,airy to ,b\v>d1 x w be ne>ly impossible ev] to f9d out its place4 ,b ! fir/ lett] :i* ne$ conc]n u is ,no4 #f1 & x is only necess>y to expla9 t ,pr(essor ,*allis 0 ! ,pr(essor ( ,a/ronomy at ,cambridge1 & 9 *>ge ( ! ,cambridge ,obs]vatory1 9 :i* (fices he _h succe$$ ,airy himself on 8 leav+ ,cambridge = ,gre5wi* "s eight ye>s e>li]4 ,no4 #f4--,,pr(essor ,,*allis to ,g4 ,b4 ,,airy4 ,extract4 ',,cambridge ,,obs]vatory1 ,feb4 #ac1 #ahdd4 ,sid5ote3 ,*allis m5tions ,adams to ,airy1 & sugge/s ,adams' visit to ,gre5wi*4 ',a "y fri5d ( m9e1 ,mr4 ,adams ( ,/4 ,john's ,college1 is work+ at ! !ory ( ,uranus1 & is desir\s ( obta9+ errors ( ! tabul> geoc5tric longitudes ( ?is planet1 :5 ne> opposition1 9 ! ye>s #ahah-ahbf1 ) ! factors = r$uc+ !m to errors ( helioc5tric longitude4 ,are y\r r$uctions ( ! planet>y obs]vations s f> advanc$ t y c\ld furni% ^! data8 & is ! reque/ "o :i* y h any objection to comply )8 ,if ,mr4 ,adams may be fav\r$ 9 ?is respect1 he is fur!r desir\s ( kn[+1 :e!r 9 ! calculation ( ! tabul> errors any alt]ations h be5 made 9 ,b\v>d's ,tables ( ,uranus besides t ( ,jupit]'s mass4' ,my answ] to him 0 z foll[s3-- ,no4 #g4--;,g4 ,b4 ,,airy to ,,pr(essor ,,*allis4 ,extract4 ',,royal ,,obs]vatory1 ,,gre5wi*1 #ahdd1 ,feb4 #ae4 ',i s5d all ! results ( ! obs]vations ( ,uranus made ) bo? in/rum5ts 7t is1 ! helioc5tric errors ( ,uranus 9 longitude & latitude f #aged to #ahcj1 = all ^? days on :i* !re 7 obs]vations1 bo? ( "r asc5sion & ( pol> di/ance74 ,no alt]ation is made 9 ,b\v>d's ,tables ( ,uranus except 9 increas+ ! two equations :i* dep5d on ,jupit] by #a_/ej "p4 ,z con/ants h be5 add$ 79 ! pr9t$ tables7 to make ! equations positive1 & z #a_/ej "p ( ! numb]s 9 ! tables has be5 add$1 #a_/ej "p ( ! con/ants has be5 subtract$ f ! f9al results4' ,pr(essor ,*allis 9 ackn[l$g+ ! receipt ( ^!1 us$ ! foll[+ expressions3-- ,no4 #h4--,,pr(essor ,,*allis to ,g4 ,b4 ,,airy4 ,extract4 ',,cambridge ,,obs]vatory1 ,feb4 #af1 #ahdd4 ',i am exce$+ly oblig$ by y\r s5d+ s complete a s]ies ( tabul> errors ( ,uranus4444 ,! li/ y h s5t w give ,mr4 ,adams ! means ( c>ry+ on 9 ! mo/ effective mann] ! inquiry 9 :i* he is engag$4' ,! next lett] %[s t ,mr4 ,adams has d]iv$ results f ^! errors4 ,no4 #i4--,,pr(essor ,,*allis to ,g4 ,b4 ,,airy4 ',,cambridge ,,obs]vatory1 ,sept4 #bb1 #ahde4 ',my fri5d ,mr4 ,adams 7:o w probably deliv] ?is note to y7 has complet$ 8 calculations respect+ ! p]turbation ( ! orbit ( ,uranus by a suppos$ ult]ior planet1 & has arriv$ at results :i* he w\ld be glad to communicate to y p]sonally1 if y c\ld sp>e him a few mom5ts ( y\r valuable "t4 ,8 calculations are f\nd$ on ! obs]vations y 7 s good z to furni% him ) "s "t ago2 & f 8 "* z a ma!matician1 & 8 practice 9 calculation1 ,i %\ld consid] ! d$uctions f 8 premises to be made 9 a tru/wor?y mann]4 ,if he %\ld n h ! good =tune to see y at ,gre5wi*1 he hopes to be all[$ to write to y on ?is subject4' ,on ! day on :i* ?is lett] 0 dat$1 ,i 0 pres5t at a meet+ ( ! ,fr5* ,in/itute4 ,i ackn[l$g$ x by ! foll[+ lett]3-- ,,no4 #aj4--;,g4 ,b4 ,,airy to ,,pr(essor ,,*allis4 ',,royal ,,obs]vatory1 ,,gre5wi*1 #ahde1 ,sept4 #bi4 ',i 01 ,i suppose1 on my way f ,france1 :5 ,mr4 ,adams call$ "h2 at all ev5ts1 ,i _h n rea*$ home1 & !re=e1 to my regret1 ,i h n se5 him4 ,w\ld y m5tion to ,mr4 ,adams t ,i am v mu* int]e/$ ) ! subject ( 8 inve/igations1 & t ,i %\ld be delight$ to he> ( !m by lett] f him8' ,on "o ( ! la/ days ( ,octob] #ahde1 ,mr4 ,adams call$ at ! ,royal ,obs]vatory1 ,gre5wi*1 9 my abs5ce & left ! foll[+ important pap]3-- ,no4 #aa4--;,j4 ,c4 ,,adams1 ,esq41 to ,g4 ,b4 ,,airy4 ,sid5ote3 ,adams' ann\ncem5t ( ! new planet4 ',accord+ to my calculations1 ! obs]v$ irregul>ities 9 ! motion ( ,uranus may be acc\nt$ = by suppos+ ! exi/5ce ( an ext]ior planet1 ! mass & orbit ( :i* are z foll[s3-- ,mean di/ance 7assum$ ne>ly 9 accordance ) ,bode's ,law7 #ch4d ,mean sid]eal motion 9 #cfe4be days #a deg4#cj'4i ,mean longitude1 #a/ ,octob] #ahde #cbc #cd ,longitude ( p]ihelion #cae #ee ,ecc5tricity #j4afaj4 ,mass 7t ( ! sun be+ unity7 #j4jjjafef4 ,= ! mod]n obs]vations ,i h us$ ! me?od ( normal places1 tak+ ! mean ( ! tabul> errors1 z giv5 by obs]vations ne> ?ree consecutive oppositions1 to correspond ) ! mean ( ! times2 & ! ,gre5wi* obs]vations h be5 us$ d[n to #ahcj3 s9ce :i*1 ! ,cambridge & ,gre5wi* obs]vations1 & ^? giv5 9 ! ,a/ronomis*e ,na*ri*t51 h be5 made use (4 ,! foll[+ are ! rema9+ errors ( mean longitude3-- ,obs]vation--,!ory4 #aghj #j4bg #aghc -#j4bc #aghf -#j4if #aghi #a4hb #agib -#j4ia #agie #j4ji #agih -#j4ii #ahja -#j4jd #ahjd #a4gf #ahjg -#j4ba #ahaj #j4ef #ahac -#j4id #ahaf -#j4ca #ahai -#b4jj #ahbb #j4cj #ahbe #a4ib #ahbh #b4be #ahca -#a4jf #ahcd -#a4dd #ahcg -#a4fb #ahdj #a4gc ,! error = #aghj is conclud$ f t = #agha giv5 by obs]vation1 comp>$ ) ^? ( f\r or five foll[+ ye>s1 & also ) ,lemonni]'s obs]vations 9 #agfi & #agga4 ',= ! anci5t obs]vations1 ! foll[+ are ! rema9+ errors3-- ,obs]vation--,!ory4 #afij #dd4d #agab #f4g #agae - #f4h #agej - #a4f #agec #e4g #agef - #d4j #agfc - #e4a #agfi #j4f #agga #aa4h ,! errors are small1 except = ,flam/e$'s obs]vation ( #afij4 ,?is be+ an isolat$ obs]vation1 v di/ant f ! re/1 ,i ?\ght x be/ n to use x 9 =m+ ! equations ( condition4 ,x is n improbable1 h[ev]1 t ?is error might be de/roy$ by a small *ange 9 ! assum$ mean motion ( ! planet4' ,i ackn[l$g$ ! receipt ( ?is pap] 9 ! foll[+ t]ms3-- ,,no4 #ab4--;,g4 ,b4 ,,airy to ,j4 ,c4 ,,adams1 ,esq4 ',,royal ,,obs]vatory1 ,,gre5wi*1 #ahde1 ,nov4 #e4 ,sid5ote3 ,airy's inquiry ab\t ! radius vector4 ',i am v mu* oblig$ by ! pap] ( results :i* y left "h a few days s9ce1 %[+ ! p]turbations on ! place ( ,uranus produc$ by a planet ) c]ta9 assum$ elem5ts4 ,! latt] numb]s are all extremely satisfactory3 ,i am n en\gh acqua9t$ ) ,flam/e$'s obs]vations ab\t #afij to say :e!r !y be> su* an error1 b ,i ?9k x extremely probable4 ',b ,i %\ld be v glad to "k :e!r ?is assum$ p]turbation w expla9 ! error ( ! radius vector ( ,uranus4 ,?is error is n[ v consid]able1 z y w be able to asc]ta9 by comp>+ ! normal equations1 giv5 9 ! ,gre5wi* obs]vations = ea* ye>1 = ! times be=e opposition ) ! times aft] opposition4' ,i h be=e /at$ t ,i consid]$ ! e/abli%m5t ( ?is error ( ! radius vector ( ,uranus to be a v important det]m9ation4 ,i !re=e consid]$ t ! trial1 :e!r ! error ( radius vector w\ld be expla9$ by ! same !ory :i* expla9$ ! error ( longitude1 w\ld be truly an exp]im5tum crucis4 ,& ,i wait$ ) mu* anxiety = ,mr4 ,adams' answ] to my qu]y4 ,_h x be5 9 ! affirmative1 ,i %\ld at once h ex]t$ all ! influ5ce :i* ,i might possess1 ei!r directly1 or indirectly ?r\gh my fri5d ,pr(essor ,*allis1 to procure ! publication ( ,mr4 ,adams' !ory4 ,f "s cause ) :i* ,i am unacqua9t$1 probably an accid5tal "o1 ,i receiv$ no imm$iate answ] to ?is inquiry4 ,i regret ?is deeply1 = _m reasons4 ,sid5ote3 ,adams' sil5ce4 ,"h we may leave ,airy's acc\nt = a few mom5ts to consid] ! reason :y he receiv$ no answ]4 ,adams 0 a v %y & retir+ "y man1 & v s5sitive2 ?\gh capable ( a great resolution1 & ( enorm\s p]sev]ance 9 c>ry+ x out4 ,we "k 7:at is n indicat$ 9 ! above acc\nt71 h[ /eadily he _h kept 9 view ! idea ( solv+ ?is great problem4 ,x 0 *>act]i/ic ( him t z e>ly z #ahda he _h =m$ a resolution to und]take x1 al?\gh at ! "t he 0 n able to ent] ^u its accompli%m5t4 ,! foll[+ memor&um1 :i* is /ill 9 exi/5ce1 hav+ be5 f\nd among 8 pap]s aft] 8 dea?1 records ^! facts3 #ahda1 ,july #c4 ,=m$ a design1 9 ! beg9n+ ( ?is week1 ( inve/igat+1 z soon z possible aft] tak+ my degree1 ! irregul>ities 9 ! motion ( ,uranus1 :i* 7 z yet unacc\nt$ =3 9 ord] to f9d :e!r !y may be attribut$ to ! action ( an undiscov]$ planet beyond x1 & if possible !nce to det]m9e ! elem5ts ( its orbit1 c41 approximately1 :i* w\ld probably lead to its discov]y4 ,accord+ly1 z soon z possible aft] tak+ 8 degree he emb>k$ ^u ! ent]prise1 & ! fir/ solution 0 made 9 ! long vacation ( #ahdc1 assum+ ! orbit ( ! unkn[n planet to be a circle ) a radius equal to twice ! mean di/ance ( ,uranus f ! sun 7an assumption :i*1 z we h se51 0 also made by ,le ,v]ri]74 ,hav+ satisfi$ himself t !re 0 a good g5]al agreem5t betwe5 8 results & ! obs]vations1 ,adams began a m complete solution2 inde$ f fir/ to la/ he made no less ?an six sep>ate solutions1 ! "o :i* he ann\nc$ to ,airy 9 ! above lett] be+ ! f\r?4 ,h5ce he _h already done an enorm\s am\nt ( "w on ! problem1 & 0 9 8 own m9d s ju/ly conv9c$ ( ! correctness & value ( 8 results t he 0 liable to =get t o!rs _h n _h ! same opportunity ( judg+ ( _! complet5ess2 & he 0 griev\sly disappo9t$ :5 8 ann\ncem5t 0 n receiv$ ) full confid5ce4 ,sid5ote3 ,8 disappo9tm5t at ,gre5wi*1 & at ,airy's "q4 ,b p]haps x %\ld fir/ be /at$ t by a s]ies ( mis*ances ,adams _h be5 already mu* disappo9t$ at ! failure ( 8 attempts to see ! ,a/ronom] ,royal on 8 visits to ,gre5wi*4 ,?is does n seem to h be5 exactly ,airy's fault2 he 01 z may well be suppos$1 an extremely busy man1 & 0 mu* occupi$ at ! "t on a "q ( great practical importance1 at ! direct reque/ ( ! ,gov]nm5t1 namely1 ! settl+ ( ! prop] gauge = railways ?r\gh\t ! c\ntry4 ,! fir/ "t ,adams call$ to see him1 he 0 actually 9 ,london sitt+ on ! ,committee :i* dealt ) ?is "q1 & ,adams 0 ask$ to call lat]2 :5 ! visit 0 repeat$1 ,airy 0 un=tunately at d9n] 7& x may be add$ t 8 h\rs = d9n] 7 some:at peculi>71 & ! butl]1 act+ some:at 9 ! mann] ( 8 k9d1 protect$ 8 ma/]'s d9n] by s5d+ away "o :om he d\btless reg>d$ z a tr\blesome visitor4 ,!re is1 z ,i h said1 little d\bt ab\t any ( ! facts1 & x seems well e/abli%$ t ,airy himself did n le>n ( ,adams' visits until aft]w>ds1 & x w\ld sc>cely be j to blame him = a s]vant's ov]sight4 ,b ,adams _h left ! pap] above reproduc$1 & ,airy ) 8 bus9ess-l habits ultimately proce$$ to deal ) x2 he wrote ! answ] giv5 above ask+ ,adams a def9ite "q1 fil$ a copy ( x ) ! orig9al lett]1 & !n dismiss$ ! matt] f 8 ?\ghts until ! reply f ,adams1 :i* he confid5tly expect$ %\ld aga9 br+ x "u notice4 ,?is fur!r disappo9tm5t 01 h[ev]1 too mu* = ,adams2 he reg>d$ ! "q put by ,airy z hav+ s obvi\s an answ] t x 0 int5d$ z an evasion1 ?\gh ?is 0 f> f be+ ! case4 ,airy 0 ?or\ghly 9 e>ne/ ab\t 8 "q1 ?\gh x mu/ be admitt$ t a m c>eful /udy ( ! problem w\ld h %[n him t x 0 unnecess>y4 ,lat]1 :5 he le>nt ( ,le ,v]ri]'s rese>*es1 he put ! same "q to him1 & receiv$ a polite b v cle> answ]1 %[+ t ! sugge/$ te/ 0 n an exp]im5tum crucis z he suppos$4 ,b ,adams did n feel equal to mak+ ?is reply2 he %rank into 8 %ell & solac$ himself only by comm5c+ afre% ano!r solution ( ! problem :i* _h s engross$ 8 life at t "t4 ,sid5ote3 ,! m]its ( ,airy's "q4 ,sid5ote3 ,! range ( possibilities4 ,i h he>d sev]e or contemptu\s ?+s said ab\t ?is "q by ^? :o mo/ blame ,airy4 ,"s ( !m h no hesitation 9 accus+ him ( intellectual incompet5ce3 !y say t x 0 ! "q ( a /upid man4 ,i ?9k t 9 ! fir/ place !y =get ! diff]5ce betwe5 a delib]ate error ( judgem5t & a m]e consequ5ce ( insuffici5t att5tion4 ,b !re is ev5 m ?an ?is to be said 9 def5ce ( ! "q4 ,! error ( radius vector came be=e ,airy 9 an entirely indep5d5t way1 & z an entirely indep5d5t ph5om5on1 f ! error ( longitude1 & !re 0 no?+ unnatural 9 reg>d+ x z requir+ indep5d5t explanation4 ,x is true t1 z ! ev5t prov$1 a m]e readju/m5t ( ! orbit ( ,uranus got rid ( ?is error ( radius vector 7?is 0 sub/antially ,le ,v]ri]'s answ] to ,airy's "q72 b we mu/ n judge ( :at 0 possible be=e ! ev5t 9 ! light ( :at we n[ "k4 ,! orig9al possibilities 7 f> wid]1 ?\gh we h =gott5 _! =m] ext5t n[ t !y h be5 n>r[$ d[n by ! discov]y4 ,if a s5try dur+ w> "t he>s a noise 9 a c]ta9 direction1 he may be compell$ to make ! assumption t x is ! movem5t ( an enemy2 & if he fires 9 t direction & kills him1 & ?us saves 8 own army f de/ruction1 he is des]v$ly applaud$ = ! success :i* att5ds 8 action4 ,b x does n foll[ t ! assumption on :i* he act$ 0 ! only possible "o4 ,or1 to take a m peaceful illu/ration1 9 play+ :i/ x sometimes becomes app>5t t ! game c only be won if ! c>ds lie 9 a c]ta9 way2 & a good play] w !reupon assume t ?is is ! fact1 & play accord+ly4 ,adams & ,le ,v]ri] play$ to w9 ! game on ! p>ticul> assumption t ! di/urbance ( ,uranus 0 due to an ext]nal planet revolv+ at a di/ance f ! sun ab\t twice t ( ,uranus2 & won x2 & we applaud !m = do+ s4 ,b x is easy to imag9e a re>rangem5t ( ! c>ds ) :i* !y w\ld h lo/ x2 & ,airy's "q simply meant t he 0 alive to ^! wid] possibilities1 & did n see ! ne$ = attempt+ to w9 ! game 9 t p>ticul> way4 ,"o su* alt]native possibility has already be5 m5tion$4 ,hans5's op9ion 01 t "o di/urb+ body w\ld n satisfy ! ph5om5a2 b he conjectur$ t !re 7 two planets beyond ,uranus4 ,ano!r conceivable alt]native is t !re 0 "s *ange 9 ! law ( gravitation at ! di/ance ( ,uranus1 :i*1 x mu/ be rememb]$1 is twice z great z t ( any planet previ\sly kn[n4 ,or "s w&]+ body might h pass$ close en\gh to ,uranus to *ange its orbit some:at sudd5ly4 ,we n[ "k1 = in/ance1 t ! sw>m ( meteorites :i* gives rise to ! well-kn[n ,novemb] meteors mu/ h pass$ v close to ,uranus 9 ,a4,d4 #abf1 assum+ t nei!r ! planet nor ! sw>m h be5 di/urb$ 9 any unkn[n mann] 9 ! meantime4 ,x is to ?is enc\nt] t we owe ! introduction ( ?is sw>m to our sol> sy/em3 w&]+ ?r\gh space1 !y met ,uranus1 & 7 swept by 8 attraction into an orbit r\nd ! sun4 ,0 !re no reaction ^u ,uranus himself8 ,! probabilities are t ! total mass ( ! sw>m 0 s small z to affect ! huge planet inappreciably2 b :o 0 to say t "s o!r sw>m ( l>g] mass1 or o!r body1 might n h approa*$ ne> ,uranus at "s date betwe5 #afij & #ahde1 & be5 responsible at any rate 9 "p = ! obs]v$ errors8 ,^! are two or ?ree suppositions f our famili> exp]i5ce2 & !re are1 ( c\rse1 limitless possibilities beyond4 ,:i* is ! true sci5tific attitude1 to be alive to !m all1 or to conc5trate att5tion ^u "o8 ,b we are p]haps w&]+ too f> f ! ma9 !me4 ,x is easy to d s 9 review+ ?is extraord9>y piece ( hi/ory1 = at almo/ e po9t new possibilities are sugge/$4 ,illu/ration3 ,,iii--,u4 ,j4 ,,le ,,v]ri]4 7,f a pr9t 9 ! possession ( ! ,royal ,a/ronomical ,society47 ,illu/ration3 ,,iv--,j4 ,g4 ,,galle4 ,,:o ,,fir/ ,,saw ,,! ,,planet ,,neptune ,sid5ote3 ,airy receives ,le ,v]ri]'s memoir4 ,we mu/ return1 h[ev]1 to ,airy's acc\nt4 ,we rea*$ ! po9t :]e he _h writt5 to ,adams 7on ,novemb] #e1 #ahde71 ask+ 8 "q ab\t ! radius vector1 & receiv$ no reply2 & !re ! matt] rema9$1 s f> z he 0 conc]n$1 until ! foll[+ ,june1 :5 ,le ,v]ri]'s memoir rea*$ him2 & we w let him give 8 own v]sion ( ! result4 ,?is memoir rea*$ me ab\t ! #bcrd or #bd? ( ,june4 ,i _c suffici5tly express ! feel+ ( delight & satisfaction :i* ,i receiv$ f x4 ,! place :i* x assign$ to ! di/urb+ planet 0 ! same1 to "o degree1 z t giv5 by ,mr4 ,adams' calculations1 :i* ,i _h p]us$ sev5 mon?s e>li]4 ,to ?is "t ,i _h consid]$ t !re 0 /ill room = d\bt ( ! accuracy ( ,mr4 ,adams' inve/igations2 = ,i ?9k t ! results ( algebraic & num]ical computations1 s long & s complicat$ z ^? ( an inv]se problem ( p]turbations1 are liable to _m risks ( error 9 ! details ( ! process3 ,i "k t !re are important num]ical errors 9 ! ,mecanique ,cele/e ( ,laplace2 9 ! ,!orie de la ,lune ( ,plana2 above all1 9 ,b\v>d's fir/ tables ( ,jupit] & ,saturn2 & to express x 9 a ^w1 ,i h always consid]$ ! correctness ( a di/ant ma!matical result to be a subject r ( moral ?an ( ma!matical evid5ce4 ,b n[ ,i felt no d\bt ( ! accuracy ( bo? calculations1 z appli$ to ! p]turbation 9 longitude4 ,i 01 h[ev]1 /ill desir\s1 z be=e1 ( le>n+ :e!r ! p]turbation 9 radius vector 0 fully expla9$4 ,i !re=e address$ to ,m4 ,le ,v]ri] ! foll[+ lett]3-- ,no4 #ac4--;,g4 ,b4 ,,airy to ,m4 ,,le ,,v]ri]4 ',royal ,obs]vatory1 ,gre5wi*1 #ahdf1 ,june #bf4 ,sid5ote3 ,he puts ! radius-vector "q to ,le ,v]ri]1 b makes no m5tion ( ,adams4 ',i h read1 ) v great int]e/1 ! acc\nt ( y\r inve/igations on ! probable place ( a planet di/urb+ ! motions ( ,uranus1 :i* is conta9$ 9 ! ,compte ,r5du de l',academie ( ,june #a2 & ,i n[ beg leave to tr\ble y ) ! foll[+ "q4 ,x appe>s1 f all ! lat] obs]vations ( ,uranus made at ,gre5wi* 7:i* are mo/ completely r$uc$ 9 ! ,gre5wi* ,obs]vations ( ea* ye>1 s z to exhibit ! effect ( an error ei!r 9 ! tabul> helioc5tric longitude1 or ! tabul> radius vector71 t ! tabul> radius vector is consid]ably too small4 ,& ,i wi% to inquire ( y :e!r ?is w\ld be a consequ5ce ( ! di/urbance produc$ by an ext]ior planet1 n[ 9 ! position :i* y h indicat$8' ,!re is m ( ! lett]1 b ?is w suffice to %[ t he wrote to ,le ,v]ri] 9 ! same way z to ,adams1 &1 z already /at$1 receiv$ a reply dat$ ?ree or f\r days lat]4 ,b ! re/ ( ! lett] conta9s no m5tion ( ,adams1 & ?us arises a second difficulty 9 und]/&+ ,airy's conduct4 ,x seems extraord9>y t :5 he wrote to ,le ,v]ri] he made no m5tion ( ! computations :i* he _h previ\sly receiv$ f ,adams2 or t he %\ld n h writt5 to ,adams1 & made "s attempt to und]/& 8 long sil5ce1 n[ t1 z he himself /ates1 he felt no d\bt ( ! accuracy ( bo? calculations4 ,! omission may h be51 & probably 01 m]e c>elessness or =getfulness2 b he c\ld h>dly be surpris$ if o!rs mi/ook x = delib]ate action4 ,sid5ote3 ,airy ann\nces ! likelihood ( a new planet1 & sugge/s a se>* = x at ,cambridge n hav+ suitable telescope at ,gre5wi* ,h[ev]1 att5tion _h n[ be5 ?or\ghly attract$ to ! ne> possibility ( f9d+ ! planet4 ,on ,june #bi1 #ahdf1 !re 0 a special meet+ ( ! ,bo>d ( ,visitors ( ,gre5wi* ,obs]vatory1 & ,airy incid5tally m5tion$ to !m ?is possibility4 ,! impression produc$ mu/ h be5 def9ite & deep2 = ,sir ,john ,h]s*el1 :o 0 pres5t1 0 bold en\gh to say on ,septemb] #aj? foll[+ to ! ,briti% ,association assembl$ at ,s\?ampton3 ,we see x 7! probable new planet7 z ,columbus saw ,am]ica f ! %ores ( ,spa94 ,its movem5ts h be5 felt trembl+ along ! f>-rea*+ l9e ( our analysis ) a c]ta9ty h>dly inf]ior to t ( ocul> demon/ration4 ,airy discuss$ ! matt] ) ,pr(essor ,*allis 7:o1 x w be rememb]$1 _h orig9ally writt5 to him on behalf ( ,adams71 sugge/+ t he %\ld imm$iately comm5ce a se>* = ! suppos$ planet at ,cambridge4 ,x may be ask$ :y ,airy did n comm5ce ?is se>* himself at ,gre5wi*1 & ! answ] is t he _h no telescope :i* he reg>d$ z l>ge en\gh = ! purpose4 ,! ,royal ,obs]vatory at ,gre5wi* has always be51 & is n[1 bett] equipp$ 9 "s respects ?an any o!r obs]vatory1 z might be expect$ f its des]v$ly great reputation2 b to possess ! l>ge/ exi/+ telescope has nev] be5 "o ( its ambitions4 ,! in/rum5ts 9 :i* x takes mo/ pride are rem>kable = _! /ead9ess & accuracy r ?an = _! size2 & at t "t ! be/ telescope possess$ by ! obs]vatory 0 n1 9 ,airy's op9ion1 l>ge en\gh to detect ! planet ) c]ta9ty4 ,9 ?is op9ion we n[ "k t he 0 mi/ak52 b1 aga91 we mu/ n judge 8 conduct be=e ! ev5t 9 ! light ( :at we h s9ce discov]$4 ,x may be recall$ "h t x 0 n until ,le ,v]ri]'s ?ird pap]1 publi%$ on ,augu/ #ca1 t he 7,le ,v]ri]7 emphatically po9t$ out t ! new planet might be ( su* a size z to h a s5sible disc2 & x 0 ?is rem>k :i* l$ imm$iately to its discov]y4 ,until ?is 0 s decisively /at$1 x mu/ h seem$ exceptionally improbable2 = we saw 9 ! la/ *apt] h[ dilig5tly ! ,zodiac _h be5 swept 9 ! se>* = m9or planets1--h[1 = in/ance1 ,h5cke _h se>*$ = fifte5 ye>s )\t success2 & x might fairly be consid]$ t if !re 7 a fairly bright object 7su* z ,neptune has s9ce be5 f\nd to be7 x w\ld h be5 discov]$ e>li]4 ,h5ce ,airy n unreasonably consid]$ x necess>y to spread 8 net = v small objects4 ,on ,july #i he wrote to ,pr(essor ,*allis z foll[s3-- ,no4 #ae4--;,g4 ,b4 ,,airy to ,,pr(essor ,,*allis4 ,,! ,,dean]y1 ,,ely1 #ahdf1 ,july #i4 ,y "k t ,i atta* importance to ! exam9ation ( t "p ( ! heav5s 9 :i* !re is 444 reason = suspect+ ! exi/5ce ( a planet ext]ior to ,uranus4 ,i h ?\ght ab\t ! way ( mak+ su* exam9ation1 b ,i am conv9c$ t 7= v>i\s reasons1 ( decl9ation1 latitude ( place1 feebl5ess ( light1 & regul>ity ( sup]9t5d5ce7 !re is no prospect :atev] ( its be+ made ) any *ance ( success1 except ) ! ,nor?umb]l& telescope4 ,n[1 ,i %\ld be glad to ask y1 9 ! fir/ place1 :e!r y c\ld make su* an exam9ation8 ,presum+ t y\r answ] w\ld be 9 ! negative1 ,i w\ld ask1 secondly1 :e!r1 suppos+ t an assi/ant 7 suppli$ to y = ?is purpose1 y w\ld sup]9t5d ! exam9ation8 ,y w readily p]ceive t all ?is is 9 a mo/ un=m$ /ate at pres5t1 & t ,i am ask+ ^! que/ions almo/ at a v5ture1 9 ! hope ( rescu+ ! matt] f a /ate :i* is1 )\t ! assi/ance t y & y\r in/rum5ts c give1 almo/ desp]ate4 ,!re=e ,i %\ld be glad to h y\r answ]1 n only respond+ simply to my que/ions1 b also ent]+ into any o!r consid]ations :i* y ?9k likely to be> on ! matt]4 ,! "t = ! said exam9ation is approa*+ ne>4 ,sid5ote3 ,*allis und]takes ! se>*4 ,sid5ote3 ,he f9ds too late t he _h obs]v$ ! planet4 ,pr(essor ,*allis did n require an assi/ant1 b det]m9$ to und]take ! "w himself1 & devis$ 8 own plan ( proc$ure2 b he also set out on ! und]tak+ ) ! expectation ( a long & ardu\s se>*4 ,no su* idea z t ( f9d+ ! planet on ! fir/ night ev] ent]$ 8 head4 ,= "o ?+1 he _h no map ( ! region to be exam9$1 = al?\gh ! map us$ by ,galle _h be5 publi%$1 no copy ( x _h z yet rea*$ ,cambridge1 & ,pr(essor ,*allis _h practically to con/ruct a map = himself4 ,9 ^! days ( photography to make su* a map is a simple matt]1 b at t "t ! process 0 t]ribly labori\s4 ,i get ov] ! gr\nd v sl[ly1 he wrote on ,septemb] #bnd to ,airy1 ?9k+ x "r to include all />s to #aj-aa magnitude2 & ,i f9d t to scrut9ise ?or\ghly 9 ?is way ! propos$ portion ( ! heav5s w require _m m obs]vations ?an ,i c take ?is ye>4 ,) su* a prospect1 x is n surpris+ t "o night's obs]vations 7 n ev5 comp>$ ) ! next2 !re w\ld be a c]ta9 economy 9 wait+ until a l>ge am\nt ( mat]ial _h be5 accumulat$1 & !n mak+ ! comp>isons all toge!r1 & ?is 0 ! c\rse adopt$4 ,b :5 ,le ,v]ri]'s ?ird pap]1 ) ! decid$ op9ion t ! planet w\ld be bright en\gh to be se5 by its disc1 ultimately rea*$ ,pr(essor ,*allis1 x naturally gave him an entirely diff]5t view ( ! possibilities2 he imm$iately began to comp>e ! obs]vations already made1 & f\nd t he _h obs]v$ ! planet e>ly 9 ,augu/4 ,b x 0 n[ too late to be fir/ 9 ! field1 = ,galle _h already made 8 ann\ncem5t ( discov]y4 ,writ+ to ,airy on ,octob] #ab1 ,*allis c\ld only lam5t t aft] f\r days' obs]v+ ! planet 0 9 8 grasp1 if only he _h exam9$ or mapp$ ! obs]vations1 & if he _h n delay$ do+ s until he _h m obs]vations to r$uce1 & if he _h n be5 v busy ) "s comet obs]vations4 ,oh6 ^! t]rible ifs :i* come s (t5 betwe5 a man & success6 ,! ?ird ( !m is a peculi>ly di/ress+ "o1 = x repres5ts t et]nal conflict betwe5 "o duty & ano!r1 :i* is s con/antly recurr+ 9 sci5tific "w4 ,%all we f9i% "o piece ( "w n[ well "u way1 or %all we att5d to some?+ m novel & m attractive8 ,*allis ?\ght 8 duty lay 9 /eadily complet+ ! comet obs]vations already begun4 ,we saw 9 ! la/ lecture h[ ! /eady pursuit ( ! discov]y ( m9or planets1 a duty :i* _h become t$i\s & app>5tly l$ n[h]e1 sudd5ly result$ 9 ! important discov]y ( ,eros4 ,b ,*allis 0 n s =tunate 9 elect+ to plod along ! beat5 track2 he w\ld h done bett] to leave x4 ,!re is no gold5 rule = ! answ]2 we mu/ be guid$ 9 ea* case by ! special circum/ances1 & ! dilemma is consequ5tly a new "o on e occasion1 & p]haps ! m try+ ) ea* repetition4 ,sid5ote3 ,s5sation caus$ by ! discov]y4 ,sid5ote3 ,n all national jeal\sy4 ,su* are briefly ! ev5ts :i* l$ to ! discov]y ( ,neptune1 :i* 0 made 9 ,g]many by direction f ,france1 :5 x might h be5 made 9 ,cambridge alone4 ,! incid5ts creat$ a great /ir at ! "t4 ,! ,acc\nt ( !m1 z read by ,airy to ! ,royal ,a/ronomical ,society on ,novemb] #ac1 #ahdf1 /raight=w>d & int]e/+ ?\gh x 01 mak+ cle> :]e he _h himself be5 at fault1 nev]!less /irr$ up angry passions 9 _m qu>t]s1 & *iefly direct$ aga9/ ,airy himself4 ,cambridge 0 furi\s at ,airy's neglig5ce1 :i* x consid]$ responsible = co/+ ! ,univ]sity a great discov]y2 & o!rs 7 equally irate at 8 attempt+ to claim = ,adams "s ( t glory :i* !y consid]$ %\ld g :olly to ,le ,v]ri]4 ,b x may be rem>k$ t feel+ 0 n purely national4 ,"s =eign]s 7 cordial 9 _! recognition ( ! "w ( ,adams1 :ile "s ( ^? mo/ eag] to oppose 8 claims 7 f\nd 9 ?is c\ntry4 ,9 _! anxiety to %[ t !y 7 free f national jeal\sy1 sci5tific m5 w5t almo/ too f> 9 ! opposite direction4 ,sid5ote3 ,! position ( ,cambridge 9 ! matt]4 ,sid5ote3 ,*allis ! weake/ po9t4 ,airy's conduct 0 c]ta9ly /range at sev]al po9ts1 z has already be5 rem>k$4 ,"o _c und]/& 8 writ+ to ,le ,v]ri] 9 ,june #ahdf )\t any m5tion ( ,adams4 ,he c\ld n ev5 mom5t>ily h =gott5 ,adams' "w2 = he tells u himself h[ he notic$ ! close correspond5ce ( 8 result ) t ( ,le ,v]ri]3 & _h he ev5 casually m5tion$ ?is fact 9 writ+ to ! latt]1 x w\ld h prep>$ ! way = 8 lat] /atem5t4 ,b we c easily und]/& ! unfav\rable impression produc$ by ?is /atem5t aft] ! discov]y _h be5 made1 :5 !re _h be5 no previ\s h9t on ! subject at all4 ,( ^? :o abus$ him ,cambridge _h ! lea/ excuse2 = !re is no d\bt t ) a reasonably compet5t ,pr(essor ( ,a/ronomy 9 ,cambridge1 %e ne$ n h ref]r$ to ,airy at all4 ,x w\ld n seem to require any great am\nt ( intellig5ce to und]take to look 9 a c]ta9 region = a /range object if "o is 9 possession ( a prop] in/rum5t4 ,we h se5 t ,*allis _h ! in/rum5t1 & :5 urg$ to d s 0 equal to ! task ( f9d+ ! planet2 b he 0 a man ( no initiative1 & ! idea ( do+ s unless direct$ by "s au?ority nev] ent]$ 8 head4 ,he _h be5 accu/om$ = _m ye>s to lean r helplessly ^u ,airy1 :o _h prec$$ him 9 (fice at ,cambridge4 ,= in/ance1 :5 appo9t$ to succe$ him1 & confront$ ) ! necessity ( lectur+ to /ud5ts1 he 0 s helpless t he wrote to implore ,airy to come back to ,cambridge & lecture = him2 & ?is 0 actually done1 ,airy obta9+ leave f ! ,gov]nm5t to leave 8 duties at ,gre5wi* = a "t 9 ord] to return to ,cambridge1 & %[ ,*allis h[ to lecture4 ,n[ x seems to me t ?is helplessness 0 ! v root ( all ! mis*ief ( :i* ,cambridge s bitt]ly compla9$4 ,i claim$ at ! outset ! privilege ( /at+ my own views1 ) :i* o!rs may n agree3 & ( all ! mi/akes & omissions made 9 ?is little piece ( hi/ory1 ! mo/ unp>donable & ! "o :i* _h mo/ s]i\s consequ5ces seems to me to be ?is3 t ,*allis nev] made ! mo/ casual inquiry z to ! result ( ! visit to ,gre5wi* :i* he himself _h direct$ ,adams to make4 ,i am judg+ him to "s ext5t by default2 because ,i assume ! facts f lack ( evid5ce to ! contr>y3 b x seems practically c]ta9 t aft] s5d+ ?is "y man to see ,airy on ?is important topic1 ,*allis !reupon wa%$ 8 h&s ( all responsibility s completely t he nev] ev5 took ! tr\ble to inquire on 8 return1 ,well6 h[ did y get on8 ,:at did ! ,a/ronom] ,royal say8 ,_h he put ?is simple "q1 :i* sc>cely requir$ ! initiative ( a ma*9e1 & le>nt 9 consequ5ce1 z he mu/ h done1 t ! s5sitive "y man ?\ght ,airy's "q trivial1 & did n propose to answ] x1 ,i ?9k we might h tru/$ ev5ts to "r !mselves4 ,ev5 ,*allis might h be5 tru/$ to reply1 ,oh6 b y mu/ answ] ! ,a/ronom] ,royal's "q3 y may ?9k x /upid1 b y _h bett] answ] x politely1 & %[ him t y "k :at y are ab\t4 ,x is unpr(itable to pursue speculation fur!r2 ?is did n happ51 & some?+ else did4 ,b ,i h always felt t my old ,univ]sity made a scapegoat ( ! wrong man 9 v5t+ its fury ^u ,airy1 :5 ! real culprit 0 among !mselves1 & 0 ! man !y _h !mselves *os5 to repres5t a/ronomy4 ,he 0 presumably ! be/ !y _h2 b if !y _h no "o bett] ?an ?is1 !y %\ld n h be5 surpris$1 & mu/ n compla91 if ?+s w5t wrong4 ,if a ,univ]sity is ambiti\s ( do+ great ?+s1 x mu/ take c>e to see t !re are m5 ( ability & initiative 9 ! "r places4 ,?is is a mo/ difficult task 9 any case1 & we require all possible inc5tives t[>ds x4 ,to bl9k ! facts :5 a weak spot is m]cilessly expos$ by ! loss ( a great opportunity is to lose "o k9d ( inc5tive1 & p]haps n ! lea/ valuable4 ,sid5ote3 ,curi\s diff]5ce betwe5 actual & suppos$ planet4 ,sid5ote3 ,pr(essor ,peirce's cont5tion t ! discov]y 0 a m]e accid5t4 ,sid5ote3 ,! explanation4 ,let u n[ turn to "s curi\s circum/ances att5d+ ?is rem>kable discov]y ( a planet by ma!matical inve/igation1 ( :i* !re are sev]al4 ,! fir/ is1 t al?\gh ,neptune 0 f\nd s ne> ! place :]e x 0 pr$ict$1 its orbit1 aft] discov]y1 prov$ to be v diff]5t f t :i* ,adams & ,le ,v]ri] _h suppos$4 ,y w rememb] t bo? calculators assum$ ! di/ance f ! sun1 9 accordance ) ,bode's ,law1 to be ne>ly twice t ( ,uranus4 ,! actual planet 0 f\nd to h a mean di/ance less ?an ?is by #be p] c5t41 an enorm\s quantity 9 su* a case4 ,= in/ance1 if ! suppos$ planet & ! real 7 />t$ r\nd ! sun toge!r1 ! real planet w\ld soon be a long way ahead ( ! o!r1 & ! ultimate di/urb+ effect ( ! two on ,uranus w\ld be v diff]5t4 ,to expla9 ! diff]5ce1 we mu/ fir/ recall a curi\s prop]ty ( su* di/urbances4 ,:5 two planets are revolv+1 s t "o takes j twice or ?ree times1 or any exact numb] ( times1 z long to revolve r\nd ! sun z ! o!r1 ! usual ma!matical expressions = ! di/urb+ action ( "o planet on ! o!r w\ld assign an inf9ite di/urbance1 :i*1 translat$ into ord9>y language1 means t we mu/ />t ) a fre% assumption1 = ?is /ate ( ?+s _c p]si/4 ,if ! p]iod ( "o 7 a little long] ?an ?is critical value1 "s ( ! ma!matical expressions w\ld be ( contr>y sign f ^? correspond+ to a p]iod a little %ort]4 ,n[ x is curi\s t ! suppos$ planet & ! real _h orbits on opposite sides ( a critical value ( ?is k9d1 namely1 t :i* w\ld assign a p]iod ( revolution = ,neptune exactly half t ( ,uranus2 & x 0 po9t$ out 9 ,am]ica by ,pr(essor ,peirce t ! effect ( ! planet imag9$ by ,adams & ,le ,v]ri] 0 ?us totally diff]5t f t ( ,neptune4 ,he !re=e decl>$ t ! ma!matical "w _h n really l$ to ! discov]y at all2 b t x _h result$ f m]e co9cid5ce1 & ?is op9ion--some:at p>adoxical ?\gh x 0--f\nd consid]able support4 ,x 0 n repli$ to by ,adams until "s ?irty ye>s lat]1 :5 a %ort reply 0 pr9t$ 9 ,li\ville's ,j\rnal4 ,! explanation is ?is3 ! expressions consid]$ by ,pr(essor ,peirce are ^? repres5t+ ! action ( ! planet ?r\gh\t an indef9ite pa/1 & did n ent] into ! problem1 :i* w\ld h be5 precisely ! same if ,neptune _h be5 sudd5ly creat$ 9 #afij2 :ile1 on ! o!r h&1 if ,neptune _h exi/$ up till #afij 7! "t :5 ,uranus 0 fir/ obs]v$1 al?\gh unkn[+ly71 & !n _h be5 de/roy$1 !re w\ld h be5 no means ( trac+ its previ\s exi/5ce4 ,9 pa/ ages x _h no d\bt be5 p]turb+ ! orbit ( ,uranus1 & _h effect$ l>ge *anges 9 x2 b if x _h !n be5 sudd5ly de/roy$1 we %\ld h _h no means ( id5tify+ ^! *anges4 ,!re might h be5 in/ead ( ,neptune ano!r planet1 su* z t suppos$ by ,adams & ,le ,v]ri]2 & its action 9 all pa/ "t w\ld h be5 v diff]5t f t ( ,neptune1 z is prop]ly repres5t$ 9 ! ma!matical expressions :i* ,pr(essor ,peirce consid]$4 ,9 consequ5ce ! orbit ( ,uranus 9 #afij w\ld h be5 v diff]5t f ! orbit z x 0 actually f\nd2 b 9 ei!r case ! ma!maticians ,adams & ,le ,v]ri] w\ld h _h to take x z !y f\nd x2 & ! di/urb+ action :i* !y consid]$ 9 _! calculations 0 ! comp>atively small di/urbance :i* began 9 #afij & end$ 9 #ahdf4 ,dur+ ?is limit$ numb] ( ye>s ! di/urbance ( ! planet !y imag9$1 al?\gh n precisely ! same z t ( ,neptune1 0 suffici5tly l x to give !m ! approximate place ( ! planet4 ,/ill x is some:at bewild]+ to look at ! ma!matical expressions = ! di/urbances z us$ by ,adams & ,le ,v]ri]1 :5 we c n[ comp>e ) !m ! actual expressions to :i* !y ought to correspond2 & "o may say frankly t !re seems to be no sort ( resemblance4 ,rec5tly a memorial ( ,adams' "w has be5 publi%$ by ! ,royal ,a/ronomical ,society2 !y h reproduc$ 9 _! ,memoirs a facsimile ( ,adams' ,,ms4 conta9+ ! fir/ solution1 :i* he made 9 #ahdc 9 ! ,long ,vacation aft] he _h tak5 8 degree1 & :i* w\ld h giv5 ! place ( ,neptune at t "t ) an error ( #ae deg44 ,9 an introduction describ+ ! :ole ( ! ,,mss41 writt5 by ,pr(essor ,r4 ,a4 ,sampson ( ,durham1 x is %[n h[ diff]5t ! actual expressions = ,neptune's influ5ce are f ^? us$ by ,adams1 & x is "o ( ! curiosities ( ?is rem>kable piece ( hi/ory t "s ( !m seem to be actually 9 ! wrong direction2 & o!rs are s little alike t x is only by fix+ our att5tion resolutely on ! consid]ations above m5tion$ t we c realise t ! analytical "w did inde$ lead to ! discov]y ( ! planet4 ,sid5ote3 ,sugge/$ elem5t>y me?od = f9d+ ,neptune illusory4 ,a second curiosity is t a mi/ak5 idea %\ld h be5 held by at lea/ "o em95t man 7,sir ,j4 ,h]s*el71 to ! effect t x w\ld h be5 possible to f9d ! place ( ! planet by a mu* simpl] ma!matical calculation ?an t actually employ$ by ,adams or ,le ,v]ri]4 ,9 8 fam\s ,outl9es ( ,a/ronomy ,sir ,john ,h]s*el describes a simple graphical me?od1 :i* he decl>es w\ld h indicat$ ! place ( ! planet )\t mu* tr\ble4 ,conc]n+ x ,i w "h m]ely quote ,pr(essor ,sampson's words3-- ,! conclusion is drawn t ,uranus arriv$ at a conjunction ) ! di/urb+ planet ab\t #ahbb2 & ?is 0 ! case4 ,plausible z ?is argum5t may seem1 x is entirely baseless4 ,= ! maximum ( p]turbations dep5d+ on ! ecc5tricities has no relation to conjunction1 & ! o!rs :i* dep5d ^u ! diff]5ces ( ! mean motions alone are ( ! nature ( =c$ oscillations1 & conjunction is n _! maximum or /ation>y position1 b _! position ( mo/ rapid *ange4 ,pr(essor ,sampson goes on to %[ t a m elaborate discussion seems q z unpromis+2 & he concludes t ! ref9em5ts employ$ 7 n sup]flu\s1 al?\gh x seems n[ cle> t a diff]5t mode ( proc$ure might h l$ m c]ta9ly to ! requir$ conclusion4 ,sid5ote3 ,! evil influ5ce ( ,bode's ,law4 ,= ! ?ird curi\s po9t is t bo? calculators %\ld h adh]$ s closely to ,bode's ,law4 ,if !y _h n _h ?is guid+ pr9ciple x seems almo/ c]ta9 t !y w\ld h made a bett] approximation to ! place ( ! planet1 = in/ead ( help+ !m x really l$ !m a/ray4 ,we h already rem>k$ t if two planets are at diff]5t di/ances f ! sun1 h[ev] slight1 & if !y are />t$ 9 _! revolution toge!r1 !y mu/ inevitably sep>ate 9 c\rse ( "t1 & ! am\nt ( sep>ation w ultimately become s]i\s4 ,?us by assum+ a di/ance = ! planet :i* 0 9 error1 h[ev] slight1 ! calculators imm$iately r5d]$ x impossible = !mselves to obta9 a place = ! planet :i* %\ld be correct = m ?an a v brief p]iod4 ,pr(essor ,sampson has giv5 ! foll[+ int]e/+ li/s ( ! dates at :i* ,adams' six solutions gave ! true place ( ! planet & ! int]vals dur+ :i* ! error 0 )9 #e deg4 ei!r way4 ,i4 ,,ii4 ,,iii4 ,,iv4 ,v4 ,,vi4 ,correct #ahbj #ahce #ahgb #ahcj #ahfa #ahef ,)9 -#e deg4 #ahab #ahbg #ahfe #ahac #ahae #ahbf #ahbg #ahdb #ahgg #ahff #ahga #ahfh ,n[ ! date at :i* x 0 mo/ important to obta9 ! correct place 0 #ahde or !reab\ts :5 x 0 propos$ to look = ! planet2 b no special precaution seems to h be5 tak5 by ei!r inve/igator to secure any advantage = ?is p>ticul> date4 ,criticis+ ! proc$ure aft] ! ev5t 7& ( c\rse ?is is a v unsatisfactory me?od ( criticism71 we %\ld say t x w\ld h be5 bett] to make sev]al assumptions z reg>ds ! di/ance in/ead ( rely+ ^u ,bode's ,law2 b no "o1 s f> z ,i "k1 has ev] tak5 ! tr\ble to write out a satisfactory solution ( ! problem z x might h be5 conduct$4 ,su* a solution w\ld be full ( int]e/1 ?\gh x c\ld only h a small weight 9 =m+ our e/imation ( ! skill ) :i* ! problem 0 solv$ 9 ! fir/ in/ance4 ,sid5ote3 ,le ,v]ri]'s errone\s limits4 ,f\r?ly1 we may notice a v curi\s po9t4 ,le ,v]ri] w5t to "s tr\ble n only to po9t out ! mo/ likely place = ! planet1 b to indicate limits outside :i* x 0 n necess>y to look4 ,?is "p ( 8 "w is specially comm5t$ ^u ) en?usiasm by ,airy1 & ,i w reproduce :at he says4 ,x is r te*nical p]haps1 b ^? :o _c foll[ ! ma!matics w be able to appreciate ! tone ( admiration4 ,sid5ote3 ,! visible disc4 ,m4 ,le ,v]ri] !n ent]s into a mo/ +5i\s computation ( ! limits betwe5 :i* ! planet mu/ be s\ght4 ,! pr9ciple is ?is3 assum+ a "t ( revolution1 all ! o!r unkn[n quantities may be v>i$ 9 su* a mann] t ?\gh ! obs]vations w n be s well repres5t$ z be=e1 yet ! errors ( obs]vation w be tol]able4 ,at la/1 on cont9u+ ! v>iation ( elem5ts1 "o error ( obs]vation w be intol]ably great4 ,!n1 by v>y+ ! elem5ts 9 ano!r way1 we may at l5g? make ano!r error ( obs]vation intol]ably great2 & s on4 ,if we compute1 = all ^! diff]5t v>ieties ( elem5ts1 ! place ( ! planet = #ahdg1 its locus w evid5tly be a discont9u\s curve or curvil9e> polygon4 ,if we d ! same ?+ ) diff]5t p]iodic times1 we %all get diff]5t polygons2 & ! extreme p]iodic times t c be all[$ w be indicat$ by ! polygons becom+ po9ts4 ,^! extreme p]iodic times are #bjg & #bcc ye>s4 ,if n[ we draw "o gr& curve1 circumscrib+ all ! polygons1 x is c]ta9 t ! planet mu/ be )9 t curve4 ,9 "o direction1 ,m4 ,le ,v]ri] f\nd no difficulty 9 assign+ a limit2 9 ! o!r he 0 oblig$ to re/rict x1 by assum+ a limit to ! ecc5tricity4 ,?us he f\nd t ! longitude ( ! planet 0 c]ta9ly n less ?an #cba deg41 & n great] ?an #cce deg4 or #cde deg41 accord+ z we limit ! ecc5tricity to #j4abe or #j4b4 ,& if we adopt #j4abe z ! limit1 !n ! mass w be includ$ betwe5 ! limits #j4jjjjg & #j4jjjba2 ei!r ( :i* exce$s t ( ,uranus4 ,f ?is circum/ance1 comb9$ ) a probable hypo!sis z to ! d5sity1 ,m4 ,le ,v]ri] conclud$ t ! planet w\ld h a visible disk1 & suffici5t light to make x conspicu\s 9 ord9>y telescopes4 ,m4 ,le ,v]ri] !n rem>ks1 z "o ( ! /rong pro(s ( ! correctness ( ! g5]al !ory1 t ! error ( radius vector is expla9$ z accurately z ! error ( longitude4 ,& f9ally1 he gives 8 op9ion t ! latitude ( ! di/urb+ planet mu/ be small4 ,my analysis ( ?is pap] has necess>ily be5 exce$+ly imp]fect1 z reg>ds ! a/ronomical & ma!matical p>ts ( x2 b ,i am s5sible t1 9 reg>d to ano!r "p1 x fails totally4 ,i _c attempt to convey to y ! impression :i* 0 made on me by ! au?or's und\bt+ confid5ce 9 ! g5]al tru? ( 8 !ory1 by ! calmness & cle>ness ) :i* he limit$ ! field ( obs]vation1 & by ! firmness ) :i* he proclaim$ to obs]v+ a/ronom]s1 ',look 9 ! place :i* ,i h indicat$1 & y w see ! planet well4' ,s9ce ,cop]nicus decl>$ t1 :5 means %\ld be discov]$ = improv+ ! vision1 x w\ld be f\nd t ,v5us _h phases l ! moon1 no?+ 79 my op9ion7 s bold1 & s ju/ifiably bold1 has be5 utt]$ 9 a/ronomical pr$iction4 ,x is "h1 if ,i mi/ake n1 t we see a "* f> sup]ior to t ( ! able1 or ent]pris+1 or indu/ri\s ma!matician2 x is "h t we see ! philosoph]4 ,sid5ote3 ,peirce's views ( ! limits4 ,b n[ ?is process ( limitation 0 faulty & actually mislead+4 ,let u comp>e :at is said ab\t x by ,pr(essor ,peirce a little lat]4 ,guid$ by ?is pr9ciple1 well e/abli%$1 & legitimate1 if conf9$ )9 prop] limits1 ,m4 ,le ,v]ri] n>r[$ ) consummate skill ! field ( rese>*1 & arriv$ at two fundam5tal propositions1 namely3-- #a/4 ,t ! mean di/ance ( ! planet _c be less ?an #ce or m ?an #cg4i4 ,! correspond+ limits ( ! "t ( sid]eal revolution are ab\t #bjg & #bcc ye>s4 #bnd4 ',t !re is only "o region 9 :i* ! di/urb+ planet c be plac$ 9 ord] to acc\nt = ! motions ( ,uranus2 t ! mean longitude ( ?is planet mu/ h be51 on ,janu>y #a1 #ahjj1 betwe5 #bdc deg4 & #beb deg44' ',nei!r ( ^! propositions is ( itself necess>ily oppos$ to ! obs]vations :i* h be5 made ^u ,neptune1 b ! two comb9$ are decid$ly inconsi/5t ) obs]vation4 ,x is impossible to f9d an orbit1 :i*1 satisfy+ ! obs]v$ di/ance & motion1 is subject to !m4 ,if1 = in/ance1 a mean longitude & "t ( revolution are adopt$ accord+ ) ! fir/1 ! correspond+ mean longitude 9 #ahjj mu/ h be5 at lea/ #dj deg4 di/ant f ! limits ( ! second proposition4 ,& aga91 if ! planet is assum$ to h _h 9 #ahjj a mean longitude ne> ! limits ( ! second proposition1 ! correspond+ "t ( revolution ) :i* its motions satisfy ! pres5t obs]vations _c exce$ #agj ye>s1 & mu/ !re=e be ab\t #dj ye>s less ?an ! limits ( ! fir/ proposition4' ,neptune _c1 !n1 be ! planet ( ,m4 ,le ,v]ri]'s !ory1 & _c acc\nt = ! obs]v$ p]turbations ( ,uranus "u ! =m ( ! inequalities involv$ 9 8 analysis--7,proc4 ,am]4 ,acad4 ,i41 #ahdf-ahdh1 p4 #ff74 ,sid5ote3 ,newcomb's criticism4 ,at ! "t :5 ,pr(essor ,peirce wrote1 ! orbit ( ,neptune 0 n suffici5tly well det]m9$ to decide :e!r "o ( ! two limitations might n be correct1 ?\gh he c\ld see t !y c\ld n bo? be "r1 & we n[ "k t !y are bo? wrong4 ,! mean di/ance ( ,neptune is #cj1 :i* does n lie betwe5 #ce & #cg4i2 & ! longitude 9 #ahjj 0 #bbe deg41 :i* does n lie betwe5 #bdc deg4 & #beb deg44 ,! +5i\s process :i* ,airy admir$ & :i* ,peirce himself calls consummately skilful 0 wrong 9 pr9ciple4 ,z ,pr(essor ,newcomb has said1 ! error 0 ! elem5t>y "o t1 in/ead ( consid]+ all ! elem5ts simultane\sly v>iable1 ,le ,v]ri] took !m "o at a "t1 consid]+ ! o!rs z fix$1 & det]m9+ ! limits betwe5 :i* ea* c\ld be conta9$ on ?is hypo!sis4 ,no solv] ( lea/ squ>e equations at ! pres5t day ought to make su* a blund]4 ,( c\rse "o tr\ble 9 ,le ,v]ri]'s demon/ration1 _h he attempt$ a rigor\s "o1 w\ld h be5 ! impossibility ( =m+ ! simultane\s equations expressive ( possible v>iations ( all ! elem5ts4 ,sid5ote3 ,elem5t ( good =tune4 ,sid5ote3 ,! map us$ by ,galle4 ,! acc\nt ( ,le ,v]ri]'s limits by ,pr(essor ,peirce1 ?\gh x exhibits ! error ) special cle>ness1 is a little unfair to ,le ,v]ri] 9 "o po9t4 ,if1 in/ead ( tak+ ! limits = ! date #ahjj1 we take !m = #ahdf 7:5 ! se>* = ,neptune 0 actually made71 we %all f9d t !y d include ! actual place ( ! planet1 z ,airy f\nd4 ,! errone\s mean motion ( ,le ,v]ri]'s planet all[$ ( 8 be+ "r at "o "t & wrong at ano!r2 & ,airy exam9$ ! limits "u fav\rable conditions1 :i* expla9s 8 en?usiasm4 ,b we c sc>cely wond] t ,pr(essor ,peirce came to ! conclusion t ! planet discov]$ 0 n ! "o po9t$ out by ,le ,v]ri]1 & _h be5 f\nd by m]e accid5t4 ,& all ^! circum/ances inevitably contribute to a g5]al impression t ! calculators _h a l>ge elem5t ( good =tune to ?ank = _! success4 ,nor ne$ we hesitate to make ?is admission1 = !re is an elem5t ( good =tune 9 all discov]ies4 ,to look no fur!r ?an ?is--if a man _h n be5 do+ a p>ticul> ?+ at a p>ticul> "t1 z he might easily n h be51 mo/ discov]ies w\ld nev] h be5 made4 ,if ,sir ,william ,h]s*el _h n be5 look+ at c]ta9 small />s = a totally diff]5t purpose he w\ld nev] h f\nd ,uranus2 & no "o ne$ hesitate to admit ! elem5t ( *ance 9 ! f9d+ ( ,neptune4 ,x is well illu/rat$ by a glance at ! map :i*1 z has be5 rem>k$1 ,galle us$ to comp>e ) ! sky on ! night :5 he made ! actual discov]y4 ,! planet 0 f\nd d[n ne> ! bottom corn] ( ! map1 & s9ce ! limits assign$ = its place might easily h v>i$ a few degrees "o way or ! o!r1 x might easily h be5 (f ! map2 9 :i* case1 x is probable t ! se>* w\ld n h be5 successful1 or at any rate t success w\ld h be5 delay$4 ,illu/ration3 ,v4--,,corn] ,,( ,,! ,,b]l9 ,,map1 ,,by ,,! ,,use ,,( ,,:i* ,,galle ,,f\nd ,,neptune4 ,sid5ote3 ,e "o made mi/akes4 ,?us1 x is a mo/ rem>kable feature ( ! discov]y ( ,neptune t mi/akes 7 made by almo/ e "o conc]n$1 h[ev] em95t4 ,airy made a mi/ake 9 reg>d+ ! "q ( ! ,radius ,vector z ( fundam5tal importance2 ,sir ,j4 ,h]s*el 0 wrong 9 describ+ an elem5t>y me?od :i* he consid]$ might h f\nd ! planet2 ,pr(essor ,peirce 0 wrong 9 suppos+ t ! actual & ! suppos$ planet 7 ess5tially diff]5t 9 _! action on ,uranus2 ,le ,v]ri] 0 wrong 9 assign+ limits outside :i* x 0 n necess>y to look :5 ! actual planet 0 outside !m2 ,adams 0 m or less wrong 9 ?9k+ t ! ecc5tricity ( ! new planet c\ld be f\nd f ! mat]ial already at disposal ( man4 ,bo? ,adams & ,le ,v]ri] gave f> too mu* importance to ,bode's ,law4 ,to review a piece ( hi/ory ( ?is k9d & note ! mi/akes ( su* m5 is c]ta9ly com=t+1 & ne$ n 9 any way less5 our admiration4 ,9 ! case ( ! inve/igators !mselves1 mu* may be set d[n to excitem5t 9 ! pres5ce ( a possible discov]y4 ,pr(essor ,sampson has provid$ u ) a small b typical in/ance ( ?is fact4 ,:5 ,adams _h c>ri$ ?r\gh all 8 computations = f9d+ ,neptune1 & 0 approa*+ ! actual place ( ! planet1 he1 :o c\ld c>ry ?r\gh fabul\s computations )\t error1 = ! fir/ "t wrote d[n a wrong figure4 ,! mi/ake 0 correct$ ^u ! ,,ms41 probably z soon z made1 b no d\bt betrays ! excitem5t :i* ! great work] c\ld n repress at ?is critical mom5t4 ,!re is a tradition t1 simil>ly1 :5 ! mighty ,newton 0 approa*+ ! completion ( 8 calculations to v]ify ! ,law ( ,gravitation1 8 excitem5t 0 s great t he 0 compell$ to assign to a fri5d ! task ( f9i%+ !m4 ,f9ally1 we may rem>k h[ ! hi/ory ( ! discov]y ( ,neptune aga9 illu/rates ! difficulty ( =mulat+ any g5]al pr9ciples = guid+ sci5tific "w4 ,sometimes x is well to foll[ ! slighte/ clue1 h[ev] imp]fectly und]/ood2 at o!r times we %all d bett] to refuse su* guidance4 ,bode's ,law po9t$ to ! exi/5ce ( m9or planets1 & might conceivably h help$ 9 f9d+ ,uranus3 b by tru/+ to x 9 ! case ( ,neptune1 ! inve/igators 7 p]il\sly ne> go+ a/ray4 ,sometimes x is bett] to foll[ resolutely ! "w 9 h& :atev] x may be1 %utt+ "o's e>s to o!r calls2 b ,airy & ,*allis lo/ _! opportunities by j ?is c\rse ( action4 ,! hi/ory ( sci5ce is full ( su* contradictory exp]i5ces2 & ! only safe conclusion seems to be t !re are no g5]al rules ( conduct = discov]y4 ,,*apt] ,,iii ,,bradley',s ,,discov]ies ,,( ,,! ,,ab]ration ,,( ,,light ,,& ,,( ,,! ,,nutation ,,( ,,! ,,e>?',s ,,axis ,sid5ote3 ,biographical me?od adopt$4 ,9 exam9+ diff]5t types ( a/ronomical discov]y1 we %all f9d c]ta9 advantages 9 v>y+ to "s ext5t ! me?od ( pres5tation4 ,9 ! two previ\s *apt]s our opportunities = le>n+ any?+ ( ! life & "* ( ^? :o made ! discov]ies h be5 slight2 b ,i propose to adopt a m directly biographical me?od 9 deal+ ) ,bradley's discov]ies1 :i* are s b\nd up ) ! simple e>ne/ness ( 8 "* t we c\ld sc>cely appreciate _! ess5tial features prop]ly )\t "s biographical /udy4 ,b ! record ( 8 life ap>t f 8 a/ronomical "w is n 9 any way s5sational2 inde$ x is s+ul>ly devoid ( incid5t4 ,he _h n ev5 a sci5tific qu>rel4 ,!re 0 sc>cely a man ( sci5ce ( t p]iod :o _h n at lea/ "o viol5t qu>rel ) "s "o1 save only ,bradley1 ^: g5tle nature seems to h kept him cle> ( !m all4 ,judg$ by ord9>y /&>ds 8 life 0 unev5tful3 & yet x may be d\bt$ :e!r1 to him :o liv$ x1 t life conta9$ "o dull mom5t4 ,incid5t came = him 9 8 sci5tific "w3 9 ! prep>ation ( app>atus1 ! mak+ ( obs]vations1 above all 9 ! h>d-?9k+ :i* he did to get at ! clue :i* w\ld expla9 !m2 & aft] review+ 8 biography1#b ,i ?9k we %all be incl9$ to admit t if ev] !re 0 a happy life1 albeit "o ( unremitt+ toil1 x 0 t ( ,james ,bradley4 ,sid5ote3 ,bradley's bir? & e>ly life4 ,sid5ote3 ,brief cl]ical c>e]4 ,he 0 born at ,%]b\rn1 9 ,gl\ce/]%ire1 9 #afic4 ,we "k little ( 8 boyhood except t he w5t to ! ,gramm> ,s*ool at ,nor?lea*1 & t ! memory ( ?is fact 0 pres]v$ at ! s*ool 9 #ahcb :5 ,rigaud 0 writ+ 8 memoir4 ,! s*ool is at pres5t %ut up = want ( funds to c>ry x on2 & all inquiries ,i h made h fail$ to elicit any trace ( ?is memory4 ,simil>ly we "k little ( 8 und]graduate days at ,ox=d1 except t he ent]$ z a common] at ,balliol 9 #agaj1 took 8 ,b4,a4 9 ! regul> c\rse 9 #agad1 & 8 ,m4,a4 9 #agag4 ,z a c>e] he *ose ! ,*ur*1 be+ orda9$ 9 #agai1 & pres5t$ to ! vic>age ( ,brid/[ 9 ,monm\?%ire2 b he only dis*>g$ ! duties ( vic> = a c\ple ( ye>s1 = 9 #agba he return$ to ,ox=d z ,pr(essor ( ,a/ronomy1 an appo9tm5t :i* involv$ ! resignation ( 8 liv+s2 & s slight 0 ?is int]ruption to 8 c>e] z an a/ronom] t we may almo/ disreg>d x1 & consid] him z an a/ronom] f ! fir/4 ,b to gu>d aga9/ a possible misconception1 let me say t ,bradley ent]$ on a cl]ical c>e] 9 a ?or\ghly e>ne/ _s2 to d o!rwise w\ld h be5 q =eign to 8 nature4 ,:5 vic> ( ,brid/[ he dis*>g$ 8 duties fai?fully t[>ds t t9y p>i%1 & moreov] 0 s active 9 8 uncle's p>i% ( ,wan/$ t he left ! reputation ( hav+ be5 curate !re1 al?\gh he held no actual appo9tm5t4 ,& ?irty ye>s lat]1 :5 he 0 ,a/ronom] ,royal & resid5t at ,gre5wi*1 & :5 ! valuable vic>age ( ,gre5wi* 0 (f]$ to him by ! ,*ancellor ( ! ,ex*equ]1 he hon\rably refus$ ! pref]m5t1 because ! duty ( a pa/or 0 incompatible ) 8 o!r /udies & necess>y engagem5ts4 ,sid5ote3 ,le>nt a/ronomy n at ,ox=d1 b f 8 uncle1 ,james ,p\nd4 ,sid5ote3 ,p\nd a fir/-rate obs]v]4 ,b n[ let u turn to ,bradley's a/ronomical education4 ,i mu/ admit1 ) deep regret1 t we _c all[ any ( ! cr$it ( x to ,ox=d4 ,!re 0 a great a/ronom] 9 ,ox=d :5 ,bradley 0 an und]graduate1 = ,edmund ,halley _h be5 appo9t$ ,savilian ,pr(essor ( ,geometry 9 #agjc1 & _h imm$iately set to "w to compute ! orbits ( comets1 :i* l$ to 8 immortal discov]y t "s ( ^! bodies return to u aga9 & aga91 especially ! "o :i* be>s 8 "n--,halley's ,comet--& returns e sev5ty-five ye>s1 be+ next expect$ ab\t #aiaj4 ,b !re is no record t ,bradley came "u ,halley's tea*+ or influ5ce z an und]graduate4 ,9 lat] ye>s ! two m5 knew ea* o!r well1 & x 0 ,halley's "o desire t[>ds ! close ( 8 life t ,bradley %\ld succe$ him z ,a/ronom] ,royal at ,gre5wi*2 a desire :i* 0 fulfill$ 9 r melan*oly fa%ion1 = ,halley di$ )\t any assurance t 8 wi% w\ld be gratifi$4 ,b ,bradley got no a/ronomical tea*+ at ,ox=d ei!r f ,halley or o!rs4 ,! art ( a/ronomical obs]vation he le>nt f 8 mat]nal uncle1 ! ,rev4 ,james ,p\nd1 ,rector ( ,wan/$1 9 ,essex4 ,he is ! man to :om we owe ,bradley's tra9+ & ! great discov]ies :i* came out ( x4 ,he 01 ,i am glad to say1 an ,ox=d man too2 v mu* an ,ox=d man2 = he seems to h sp5t "s ?irte5 ye>s !re migrat+ f "o ,hall to ano!r4 ,8 record inde$ 0 su* z good tutors ( colleges fr[n ^u2 = x 0 sev5 ye>s be=e he manag$ to take a degree at all2 & he c\ld n settle to any?+4 ,aft] t5 ye>s at ,ox=d he ?\ght he w\ld try m$ic9e2 aft] ?ree ye>s m he gave x up & w5t out 9 #agjj z *apla9 to ! ,ea/ ,indies4 ,b he seems to h be5 a ?or\ghly lovable man1 = news 0 br\ght ( him f\r ye>s lat] t he _h a m9d to come home1 b 0 dissuad$ by ! ,gov]nor say+ t if ,dr4 ,p\nd goes1 ,i & ! re/ ( ! ,company w n /ay beh9d4 ,soon aft]w>ds ! settlem5t 0 attack$ 9 an insurrection1 & ,p\nd 0 "o ( ! few :o escap$ ) 8 life1 los+ h[ev] all ! prop]ty he _h gradually acquir$4 ,he return$ to ,engl& 9 #agjf1 & 0 pres5t$ to ! liv+ ( ,wan/$2 m>ri$ twice1 & end$ 8 days 9 peace & fair prosp]ity 9 #agbd4 ,su* are briefly ! facts ab\t ,bradley's uncle1 ,james ,p\nd2 b ! mo/ important ( all rema9s to be told--t someh[ or o!r he _h le>nt to make fir/-rate a/ronomical obs]vations1 h[ or :5 is n record$2 b 9 #agai he 0 already s skill$ t ,sir ,isaac ,newton made him a pres5t ( fifty gu9eas = "s obs]vations2 & repeat$ ! gift 9 ! foll[+ ye>2 & ev5 ?ree ye>s be=e ?is we f9d ,halley writ+ to ask = c]ta9 obs]vations f ,mr4 ,p\nd4 ,sid5ote3 ,bradley work$ ) him4 ,) ?is excell5t man ,bradley us$ frequ5tly to /ay4 ,to 8 nephew he seems to h be5 m l a fa!r ?an an uncle4 ,:5 8 nephew _h smallpox 9 #agag1 he nurs$ him ?r\gh x2 & he supplem5t$ f 8 own pocket ! scanty all[ance :i* 0 all t ,bradley's own fa!r c\ld af=d4 ,b :at conc]ns u mo/ is t he fo/]$1 if he did n actually implant1 a love ( a/ronomical obs]vation 9 8 nephew4 ,! two work$ toge!r1 ent]+ _! obs]vations "o aft] ! o!r on ! same pap]2 & x 0 to ! pair ( !m toge!r1 r ?an to ! uncle alone1 t ,newton made 8 pr9cely pres5ts1 & ,halley wrote = help 9 8 obs]vations4 ,!re seems to be no d\bt t ! uncle & nephew 7 ab\t ?is "t ! be/ a/ronomical obs]v]s 9 ! _w4 ,!re 0 no rivalry betwe5 !m1 & !re=e !re is no ne$ to discuss :e!r ! p>tn]%ip 0 "o ( equal m]it on bo? sides2 b x is int]e/+ to note t x probably 04 ,! ability ( ,p\nd 0 und\bt$2 _m 7 ke5ly desir\s t he1 & n 8 nephew1 %\ld be elect$ to ! ,ox=d ,*air 9 #agba1 b he felt unequal to ! duties at 8 advanc$ age4 ,on ! o!r h&1 :5 ,bradley lo/ 8 uncle's help1 !re 0 no trace ( falt]+ 9 8 /eps to betray previ\s dep5d5ce on a support+ or guid+ h&4 ,he walk$ erect & firm1 & trod pa?s :]e ev5 8 uncle might n h be5 able to foll[4 ,sid5ote3 ,! "w done by ,p\nd & ,bradley4 ,sid5ote3 ,use ( v long telescopes4 ,sid5ote3 ,reason = great l5g?4 ,a few in/ances w suffice to %[ ! k9d ( obs]vations made by ?is notable firm ( ,p\nd & ,bradley4 ,!y obs]v$ ! positions ( ! fix$ />s & nebulae3 ^! be+ g5]ally ! results requir$ by ,halley & ,newton4 ,!y also obs]v$ ! places ( ! planets among ! />s1 & especially ! planet ,m>s1 & det]m9$ its di/ance f ! ,e>? by ! me?od ( p>allax1 ?us anticipat+ ! mod]n /&>d me?od ( f9d+ ! ,sun's di/ance2 & ?\gh ) _! imp]fect in/rum5ts !y did n obta9 a great] accuracy ?an #a 9 #aj1 /ill ?is 0 a great advance on :at _h be5 done be=e1 & excit$ ! wond] & admiration ( ,halley4 ,!y also paid "s att5tion to d\ble />s1 & did a great deal ( "w on ,jupit]'s satellites4 ,we might pr(itably l+] ov] ! records ( ^! e>ly ye>s1 :i* are full ( int]e/1 b we mu/ press on to ! "t ( ! great discov]ies1 & we w dismiss !m ) brief illu/rations ( ?ree po9ts3 ,bradley's assiduity1 8 skill 9 calculation1 & 8 wond]ful skill 9 ! managem5t ( in/rum5ts4 ,( 8 assiduity an example is af=d$ by 8 calculations ( ! orbits ( two comets :i* are /ill extant4 ,"o ( !m fills ?irty-two pages ( foolscap1 & ! o!r sixty2 & x mu/ be rememb]$ t ! calculations !mselves 7 q novel at t "t4 ,( 8 skill 9 calculation1 ap>t f 8 assiduity1 we h a pro( 9 a pap] communicat$ to ! ,royal ,society r lat] 7#agbf71 :]e he det]m9es ! longitudes ( ,lisbon & ,new ,york f ! eclipses ( ,jupit]'s satellites1 us+ obs]vations :i* 7 n simultane\s1 & _h !re=e to be correct$ by an +5i\s process :i* ,bradley devis$ expressly = ?is purpose4 ,& f9ally1 8 skill 9 ! managem5t ( in/rum5ts is %[n by 8 measur+ ! diamet] ( ! planet ,v5us ) a telescope actually #bab-a_/d feet 9 l5g?4 ,x is difficult = u to realise 9 ^! days :at ?is means2 ev5 ! longe/ telescope ( mod]n times does n exce$ #ajj feet 9 l5g?1 & x is m\nt$ s conv5i5tly ) all ! res\rces ( mod]n eng9e]+1 9 ! %ape ( ris+ floors1 c41 t ! managem5t ( x is no m difficult ?an t ( a #aj-;foot telescope4 ,b ,bradley _h no eng9e]+ appliances beyond a pole to hold up "o end ( ! telescope & 8 own clev] f+]s to "w ! o!r2 & he manag$ to po9t ! unwieldy weapon accurately to ! planet1 & measure ! diamet] ) an exactness :i* w\ld d cr$it to mod]n times4 ,a few words ( explanation may be giv5 :y su* long telescopes 7 us$ at all4 ,! reason lay 9 ! difficulty ( gett+ rid ( col\r$ images1 due to ! composite "* ( :ite light4 ,:5ev] we use a s+le l5s to =m an image1 col\r$ fr+es appe>4 ,n[adays we "k t by mak+ two l5ses ( diff]5t k9ds ( glass & putt+ !m toge!r1 we c practically get rid ( ^! col\r$ fr+es2 b ?is discov]y _h n be5 made 9 ,bradley's "t4 ,! only kn[n ways ( deal+ ) ! evil !n 7 to use a reflect+ telescope l ,newton & ,gregory1 or if a l5s 0 us$1 to make "o ( v great focal l5g?2 & h5ce ! prim>y necessity = ^! v long telescopes4 ,!y _h ano!r advantage 9 produc+ a l>ge image1 or !y w\ld probably h giv5 way to ! reflector4 ,?is advantage is gradually br++ !m back into use1 & p]haps 9 ! eclipse ( #aije we may use a telescope z long z ,bradley's2 b we %all n use x z he did 9 any case4 ,x w be laid com=tably flat on ! gr\nd1 & ! rays ( light reflect$ into x by a coelo/at4 ,sid5ote3 ,bradley appo9t$ at ,ox=d1 b cont9ues to "w at ,wan/$4 ,9 #agba ,bradley 0 appo9t$ to ! ,savilian ,pr(essor%ip ( ,a/ronomy at ,ox=d1 vacant by ! dea? ( ,dr4 ,john ,keill4 ,once x became cle> t !re 0 no *ance ( secur+ 8 uncle = ?is position1 ,bradley himself 0 support$ en?usia/ically by all ^? ^: support 0 wor? hav+1 especially by ! ,e>l ( ,macclesfield1 :o 0 !n ,"l ,*ancellor2 by ,m>t9 ,f\lkes1 :o 0 aft]w>ds ! ,presid5t ( ! ,royal ,society2 & by ,sir ,isaac ,newton himself4 ,he 0 accord+ly elect$ on ,octob] #ca1 #agba1 & =?) resign$ 8 liv+s4 ,8 resignation ( ! liv+s 0 necessitat$ by a def9ite /atute ( ! ,univ]sity relat+ to ! ,pr(essor%ip1 & n by ! exi/5ce ( any v on]\s duties atta*+ to x2 inde$ su* duties seem to h be5 conspicu\sly abs5t1 & aft] ,bradley's election he pass$ m "t ?an ev] ) 8 uncle 9 ,wan/$1 mak+ ! a/ronomical obs]vations :i* bo? lov$2 = !re 0 n ! ve/ige ( an obs]vatory 9 ,ox=d4 ,8 uncle's dea? 9 #agbd int]rupt$ ! cont9uity ( ^! jo9t obs]vations1 & by an odd accid5t prep>$ ! way = ,bradley's great discov]y4 ,he 0 fa9 to seek else:]e t companion%ip 9 8 "w :i* _h become s ess5tial to him1 & 8 new fri5d gave a new b5t to 8 obs]vations4 ,sid5ote3 ,samuel ,molyneux4 ,sid5ote3 ,attempts to f9d /ell> p>allax4 ,samuel ,molyneux 0 a g5tleman ( =tune mu* atta*$ to sci5ce1 & p>ticul>ly to a/ronomy1 :o 0 liv+ ab\t ?is "t at ,kew4 ,he 0 "o ( ! few1 moreov]1 :o are n cont5t m]ely to amuse !mselves ) a telescope1 b _h ! ambition to d "s real e>ne/ "w1 & ! c\rage to *oose a problem :i* _h baffl$ ! human race = m ?an a c5tury4 ,! !ory ( ,cop]nicus1 t ! e>? mov$ r\nd ! sun1 necessitat$ a correspond+ app>5t *ange 9 ! places ( ! />s1 "o relatively to ano!r2 & x 0 a /&+ difficulty 9 ! way ( accept+ ?is !ory t no su* *ange c\ld be detect$4 ,9 ! old days be=e ! telescope x 0 p]haps easy to und]/& t ! *ange might be too small to be notic$1 b ! telescope _h made x possible to measure *anges ( position at lea/ a hundr$ times z small z be=e1 & /ill no p>allax1 z ! a/ronomical t]m goes1 c\ld be f\nd = ! />s4 ,! obs]vations ( ,galileo1 & ! measures ( ,ty*o ,brahe1 z r$uc$ to sy/ematic laws by ,kepl]1 & f9ally by ! great ,newton1 made x cle> t ! ,cop]nican !ory 0 true3 b no "o _h succe$$ 9 prov+ its tru? 9 ?is p>ticul> way4 ,samuel ,molyneux mu/ h be5 a man ( great c\rage to set himself to try to crack ?is h>d nut2 & we c und]/& ! attraction :i* 8 ent]prise mu/ h _h = ,bradley1 :o _h j lo/ ! belov$ colleague ( _m c\rage\s a/ronomical und]tak+s4 ,8 co-op]ation seems to h be5 welcom$ f ! fir/2 8 help 0 invit$ & freely giv5 9 sett+ up ! in/rum5t1 & he =tunately _h ! leisure to sp5d consid]able "t at ,kew mak+ ! obs]vations ) ,molyneux1 j z he _h be5 wont to obs]ve ) 8 uncle4 ,i mu/ n[ briefly expla9 :at ^! obs]vations 74 ,!re is a bright /> gamma ,draconis1 :i* passes almo/ directly ov]head 9 ! latitude ( ,london4 ,its position is sl[ly *ang+ ow+ to ! precession ( ! equ9oxes1 b = two c5turies x has be51 & is /ill1 "u con/ant obs]vation by ,london a/ronom]s ow+ to ?is circum/ance1 t x passes directly ov]head1 & s its position is practically undi/urb$ by ! refraction ( our atmosph]e4 ,sid5ote3 ,! in/rum5t4 ,sid5ote3 ,expect$ results4 ,x 0 !re=e ?\ght at ! "t t1 !re be+ no di/urbance f refraction1 ! di/urbance f precession be+ accurately kn[n1 & !re be+ no?+ else to di/urb ! position b p>allax 7! app>5t %ift due to ! e>?'s motion :i* x 0 desirable to f9d71 ?is /> ought to be a specially fav\rable object = ! det]m9ation ( p>allax4 ,inde$ x _h be5 ann\nc$ _m ye>s be=e by ,hooke t its p>allax _h be5 f\nd2 b 8 obs]vations 7 n altoge!r satisfactory1 & x 0 ) a view ( ei!r confirm+ !m or see+ :at 0 wrong ) !m t ,molyneux & ,bradley />t$ _! se>*4 ,!y set up a mu* m delicate piece ( app>atus ?an ,hooke _h employ$4 ,x 0 a telescope #bd feet long po9t$ upw>ds to ! />1 & firmly atta*$ to a l>ge /ack ( brick *imneys )9 ! h\se4 ,! telescope 0 n absolutely fix$1 = ! l[] end c\ld be mov$ by a screw s z to make x po9t accurately to ! />1 & a plumb-l9e %[$ h[ f> x 0 f ! v]tical :5 s po9t+4 ,h5ce if ! /> *ang$ its position1 h[ev] slightly1 ! read+ ( ?is screw w\ld %[ ! *ange4 ,n[1 be=e sett+ out on ! obs]vations1 ! obs]v]s knew :at to expect if ! /> _h a real p>allax2 t is to say1 !y knew t ! /> w\ld seem to be f>!/ s\? 9 ,decemb]1 f>!/ nor? 9 ,june1 & at int]m$iate positions 9 ,m>* & ,septemb]2 ?\gh !y did n "k h[ mu* f>!r s\? x w\ld appe> 9 ,decemb] ?an 9 ,june--?is 0 exactly ! po9t to be decid$4 ,illu/ration3 ,,fig4 #b4 ,sid5ote3 ,unexpect$ results4 ,! reason ( ?is w be cle> f ,fig4 #b4 ,rem>k1 h[ev]1 t ?is figure & ! correspond+ figure #d d n repres5t ! case ( ,bradley's />1 gamma ,draconis3 ano!r /> has be5 *os5 :i* simplifies ! diagram1 ?\gh ! pr9ciple is ess5tially ! same4 ,let ,a ,b ,c ,d repres5t ! e>?'s orbit1 ! e>? be+ at ,a 9 ,june1 at ,b 9 ,septemb]1 & s on1 & let ,k repres5t ! position ( ! /> on ! l9e ,d ,b4 ,!n 9 ,m>* & ,septemb] x w be se5 f ! e>? 9 ! same direction1 namely1 ,d ,b ,k2 b ! directions 9 :i* x is se5 9 ,june & ,decemb]1 viz4 ,a ,k & ,c ,k1 are incl9$ 9 opposite ways to ?is l9e4 ,! f>!r away ! /> is1 ! less w ?is incl9ation or p>allax be2 & ! /> is actually s f> away t ! incl9ation c only be detect$ ) ! utmo/ difficulty3 ! l9es ,c ,k & ,a ,k are s5sibly p>allel to ,d ,b ,k4 ,b ,bradley did n "k ?is2 x 0 j ?is po9t :i* he 0 to exam9e1 & he expect$ ! greate/ incl9ation 9 "o direction to be 9 ,decemb]4 ,accord+ly :5 a few obs]vations _h be5 made on ,decemb] #c1 #e1 #aa1 & #ab x 0 ?\ght t ! /> _h be5 caught at its mo/ s\!rly app>5t position1 & might be expect$ !reaft] to move nor?w>ds1 if at all4 ,b :5 ,bradley repeat$ ! obs]vation on ,decemb] #ag1 he f\nd to 8 great surprise t ! /> 0 /ill mov+ s\?w>ds4 ,"h 0 some?+ q new & unexpect$1 & su* a ke5 obs]v] z ,bradley 0 at once on ! al]t4 ,he soon f\nd t ! *anges 9 ! position ( ! /> 7 ( a totally unexpect$ "*4 ,in/ead ( ! extreme positions be+ occupi$ 9 ,june & ,decemb]1 !y 7 occupi$ 9 ,m>* & ,septemb]1 j midway betwe5 ^!4 ,& ! range 9 position 0 q l>ge1 ab\t #dj--n a quantity :i* c\ld h be5 detect$ 9 ! days be=e telescopes1 b "o :i* 0 unmi/akable ) an in/rum5t ( ! mo/ mod]ate measur+ capacity4 ,sid5ote3 ,t5tative explanations4 ,:at1 !n1 0 ! cause ( ?is q un=ese5 behavi\r on ! "p ( ! />8 ,! fir/ ?\ght ( ! obs]v]s 0 t some?+ might be wrong ) _! in/rum5t1 & x 0 c>efully exam9$1 b )\t result4 ,! next 0 t ! app>5t movem5t 0 9 ! plumb-l9e1 ! l9e ( ref]5ce4 ,if ! :ole e>?1 in/ead ( c>ry+ its axis r\nd ! sun 9 a con/ant direction1 7 to be execut+ an oscillation1 !n all our plumb-l9es w\ld oscillate1 & :5 ! direction ( a /> l gamma ,draconis 0 comp>$ ) t ( ! plumb-l9e x w\ld seem to v>y1 ow+ actually to ! v>iation 9 ! plumb-l9e4 ,! e>? might h a motion ( ?is k9d 9 two ways1 :i* x w be necess>y = u to di/+ui%1 & ! adopt$ names = !m are nutation ( ! axis & v>iation ( latitude respectively4 ,9 ! case ( nutation ! ,nor? ,pole rema9s 9 ! same geographical position1 b po9ts to a diff]5t "p ( ! heav5s4 ,! v>iation ( latitude1 on ! o!r h&1 means t ! ,nor? ,pole w&]s ab\t on ! e>? itself4 ,we %all ref] to ! second ph5om5on m p>ticul>ly 9 ! six? *apt]4 ,sid5ote3 ,nutation8 ,sid5ote3 ,anomal\s refraction4 ,b x 0 ! fir/ k9d ( *ange1 ! nutation1 :i* ,bradley suspect$2 & v e>ly 9 ! s]ies ( obs]vations he _h already begun to te/ ?is hypo!sis4 ,if x 0 n ! />1 b ! e>? & ! plumb-l9e1 :i* 7 9 motion1 !n o!r />s ought to be affect$4 ,! telescope _h be5 delib]ately re/rict$ 9 its position to suit gamma ,draconis2 b s9ce ! />s circle r\nd ! ,pole1 if we draw a n>r[ belt 9 ! heav5s ) ! ,pole z c5tre1 & includ+ gamma ,draconis1 ! o!r />s includ$ w\ld make ! same circuit1 prec$+ or foll[+ gamma ,draconis by a con/ant int]val4 ,mo/ ( !m w\ld be too fa9t = obs]vation ) ,bradley's telescope2 b !re 0 "o bright en\gh to be obs]v$1 :i* also came )9 its limit$ range1 & x 0 promptly put "u surveillance :5 a nutation ( ! e>?'s axis 0 suspect$4 ,c>eful wat*+ %[$ t x 0 n affect$ 9 ! same way z gamma ,draconis1 & h5ce ! movem5t c\ld n be 9 ! plumb-l9e4 ,0 !re1 !n1 aft] all1 "s effect ( ! e>?'s atmosph]e :i* _h be5 ov]look$8 ,we h already rem>k$ t s9ce ! /> passes directly ov]head !re %\ld be practically no refraction2 & ?is assumption 0 made by ,molyneux & ,bradley 9 *oos+ ?is p>ticul> /> = obs]vation4 ,x foll[s at once1 if we assume t ! atmosph]e surr\nds ! e>? 9 sph]ical lay]s4 ,b p]haps ?is 0 n s8 ,p]haps1 on ! contr>y1 ! atmosph]e 0 de=m$ by ! motion ( ! e>?1 /ream+ out beh9d h] l ! smoke ( a mov+ eng9e8 ,no possibility mu/ be ov]look$ if ! explanation ( ?is puzzl+ fact 0 to be got at4 ,illu/ration3 ,,fig4 #c4 ,! way 9 :i* a de=mation ( ! atmosph]e might expla9 ! ph5om5on is be/ se5 by a diagram4 ,fir/1 x mu/ be rem>k$ t rays ( light are only b5t by ! e>?'s atmosph]e1 or refract$1 if !y ent] x obliquely4 ,if ! atmosph]e 7 ( ! same d5sity ?r\gh\t1 l a piece ( glass1 !n a v]tical ray ( light1 ,a ,b 7see ,fig4 #c71 ent]+ ! atmosph]e at ,b w\ld suff] no b5d+ or refraction1 & a /> %9+ f ! direction ,a ,b w\ld be se5 truly 9 t direction f ,c4 ,b an oblique ray1 ,d ,e1 w\ld be b5t on ent]+ ! atmosph]e at ,e along ! pa? ,,ef1 & a /> %9+ along ,d ,e w\ld appe> f ,f to be %9+ along ! dott$ l9e ,g ,e ,f4 ,! atmosph]e is n ( ! same d5sity ?r\gh\t1 b ?9s out z we g upw>ds f ! e>?2 & 9 consequ5ce !re is no cle>-cut surface1 ,b ,e1 & no sudd5 b5d+ ( ! rays z at ,e3 !y are gradually b5t at an inf9ite succession ( imag9>y surfaces4 ,b x /ill rema9s true t !re is no b5d+ at all = v]tical rays2 & ( oblique rays ^? mo/ oblique are mo/ b5t4 ,illu/ration3 ,,fig4 #d4 ,n[1 suppose ! atmosph]e ( ! e>? took up1 ow+ to its revolution r\nd ! sun1 an elongat$ %ape l t indicat$ 9 diagram #d1 & suppose ! /> to be at a great di/ance away to ! "r ( ! diagram4 ,:5 ! e>? is 9 ! position labell$ ,june1 ! light w\ld fall v]tically on ! nose ( ! atmosph]e at ,a1 & !re w\ld be no refraction4 ,simil>ly 9 ,decemb] ! light w\ld fall at ,c on ! /]n1 also v]tically1 & !re w\ld be no refraction4 ,! rays f ! di/ant /> 9 ,decemb] are to be tak5 z s5sibly p>allel to ^? receiv$ 9 ,june1 not)/&+ t ! e>? is on ! opposite side ( ! sun1 z 0 rem>k$ on p4 #ih4 ,b 9 ,m>* & ,septemb] ! rays w\ld /rike obliquely on ! sides ( ! suppos$ figure1 & ?us be b5t 9 opposite directions1 z indicat$ by ! dott$ l9es2 & ! extreme positions w\ld ?us occur 9 ,m>* & ,septemb]1 z _h be5 obs]v$4 ,! explanation ?us f> seems satisfactory en\gh4 ,b we h assum$ ! /> to lie 9 ! plane ( ! e>?'s orbit2 & ! />s "u obs]vation by ,bradley did n lie 9 ?is plane1 nor did !y lie 9 directions equally incl9$ to x4 ,mak+ ! prop] all[ance = _! directions1 x 0 f\nd impossible to fit 9 ! facts ) ?is hypo!sis1 :i* _h ultimately to be ab&on$4 ,sid5ote3 ,delay 9 f9d+ real explanation4 ,sid5ote3 ,bradley sets up ano!r in/rum5t at ,wan/$4 ,sid5ote3 ,f9ds ! "r clue4 ,sid5ote3 ,a w9d-vane on a boat4 ,x is rem>kable to f9d t two or ?ree ye>s w5t by be=e ! real explanation ( ?is new ph5om5on occurr$ to ,bradley1 & dur+ ?is "t he mu/ h done "s h>d ?9k+4 ,we h all _h exp]i5ce ( ! k9d ( ?9k+ if only 9 ! guess+ ( conundrums4 ,we "k ! app>5t hopelessness ( ! que/ at ! outset3 ! rack+ ( our bra9s = a clue1 ! too frequ5t despair & giv+ x up1 & ! simplicity ( ! answ] :5 once x is decl>$4 ,b ) sci5tific conundrums ! exp$i5t ( giv+ x up is n available4 ,we mu/ f9d ! answ] = ourselves or rema9 9 ignorance2 & ?\gh we may feel sure t ! answ] :5 f\nd w be z simple z t to ! be/ conundrum1 ?is expect$ simplicity does n seem to aid u 9 ! se>*4 ,bradley 0 n cont5t ) sitt+ d[n to ?9k3 he set to "w to accumulate m facts4 ,molyneux's in/rum5t only all[$ ( ! obs]vation ( two />s1 gamma ,draconis & ! small /> above m5tion$4 ,bradley det]m9$ to h an in/rum5t ( 8 own :i* %\ld comm& a wid] range ( />s2 & by ?is "t he 0 able to return to 8 uncle's h\se at ,wan/$ = ?is purpose4 ,8 uncle _h be5 dead = two or ?ree ye>s1 & ! memory ( ! loss 0 becom+ mell[$ ) "t4 ,8 uncle's wid[ 0 only too glad to welcome back h] nephew1 ?\gh no long] to ! old rectory1 & %e all[$ him to set up a long telescope1 ev5 ?\gh he cut holes 9 h] floor to pass x ?r\gh4 ,! object-glass end 0 out on ! ro( & ! eye end d[n 9 ! coal cell>2 & accord+ly 9 ?is coal cell> ,bradley made ! obs]vations :i* l$ to 8 immortal discov]y4 ,he _h a li/ ( sev5ty />s to obs]ve1 fifty ( :i* he obs]v$ pretty regul>ly4 ,x may seem odd t he did n set up ?is new in/rum5t at ,ox=d1 b we f9d f an old memor&um t 8 pr(essor%ip 0 n br++ him 9 q ,l#adj a ye>1 & probably he 0 glad to accept 8 aunt's hospitality = reasons ( economy4 ,by wat*+ ^! diff]5t />s he gradually got a cle> conception ( ! laws ( ab]ration4 ,! real solution ( ! problem1 accord+ to a well-au!nticat$ acc\nt1 occurr$ to him almo/ accid5tally4 ,we all "k ! /ory ( ! apple fall+ & sett+ ,newton to ?9k ab\t ! causes ( gravitation4 ,x 0 a simil>ly trivial circum/ance :i* sugge/$ to ,bradley ! explanation :i* he _h be5 seek+ = two or ?ree ye>s 9 va94 ,9 8 own words1 at la/1 :5 he despair$ ( be+ able to acc\nt = ! ph5om5a :i* he _h obs]v$1 a satisfactory explanation ( !m occurr$ to him all at once :5 he 0 n 9 se>* ( x4 ,he accompani$ a pleasure p>ty 9 a sail ^u ! riv] ,?ames4 ,! boat 9 :i* !y 7 0 provid$ ) a ma/ :i* _h a vane at ! top ( x4 ,x blew a mod]ate w9d1 & ! p>ty sail$ up & d[n ! riv] = a consid]able "t4 ,dr4 ,bradley rem>k$ t e "t ! boat put ab\t ! vane at ! top ( ! boat's ma/ %ift$ a little1 z if !re _h be5 a slight *ange 9 ! direction ( ! w9d4 ,he obs]v$ ?is ?ree or f\r times )\t speak+2 at la/ he m5tion$ x to ! sailors1 & express$ 8 surprise t ! w9d %\ld %ift s regul>ly e "t !y put ab\t4 ,! sailors told him t ! w9d _h n %ift$1 b t ! app>5t *ange 0 ow+ to ! *ange 9 ! direction ( ! boat1 & assur$ him t ! same ?+ inv>iably happ5$ 9 all cases4 ,?is accid5tal obs]vation l$ him to conclude t ! ph5om5on :i* _h puzzl$ him s mu* 0 ow+ to ! comb9$ motion ( light & ( ! e>?4 ,to expla9 exactly :at is meant we mu/ aga9 h rec\rse to a diagram2 & we may also make use ( an illu/ration :i* has become classical4 ,illu/ration3 ,,fig4 #e4 ,sid5ote3 ,analogy ( ra94 ,if ra9 is fall+ v]tically1 z repres5t$ by ! direction ,a ,b2 & if a p$e/rian is walk+ horizontally 9 ! direction ,c ,d1 ! ra9 w appe> to him to be com+ 9 an incl9$ direction1 ,e ,f1 & he w f9d x bett] to tilt 8 umbrella =w>ds4 ,! quick] 8 pace ! m he w f9d x advisable to tilt ! umbrella4 ,?is analogy 0 /at$ by ,lal&e be=e ! days ( umbrellas 9 ! foll[+ words3 ,je suppose que1 dans un temps calme1 la pluie tombe p]p5diculairem5t1 et qu'on soit dans une voiture ouv]te sur le devant2 si la voiture e/ en repos1 on ne recoit pas la mo9dre g\tte de pluie2 si la voiture avance avec rapidite1 la pluie entre s5siblem5t1 comme si elle avoit pris une direction oblique4 ,lal&e's example1 modifi$ to suit mod]n conditions1 has be5 g5]ally adopt$ by tea*]s1 & 9 exam9ations c&idates produce graphic pictures ( ! /ation>y1 ! mod]ate-pac$1 & ! fly+1 possessors ( umbrellas4 ,sid5ote3 ,ab]ration4 ,apply+ x to ! ph5om5on :i* x is int5d$ to illu/rate1 if light is be+ receiv$ f a /> by an e>?1 travell+ across ! direction ( ! ray1 ! telescope 7:i* 9 ?is case repres5ts ! umbrella7 mu/ be tilt$ =w>d to cat* ! light4 ,n[ on ref]5ce to ,fig4 #d x w be se5 t ! e>? is travell+ across ! direction ( rays f ! /> 9 ,m>* & ,septemb]2 & 9 opposite directions 9 ! two cases4 ,h5ce ! telescope mu/ be tilt$ a little1 9 opposite directions1 to cat* ! light2 or1 9 o!r words1 ! /> w appe> to be f>!/ s\? 9 ,m>*1 f>!/ nor? 9 ,septemb]4 ,& s at la/ ! puzzle 0 solv$1 & ! solution 0 f\nd1 z s (t5 happ5s1 to be ( ! simple/ k9d2 s simple :5 once we "k1 & s t]ribly h>d to imag9e :5 we don't6 ,x may com=t u 9 our /ruggles ) m9or problems to reflect t ,bradley manfully /uck to 8 problem = two or ?ree ye>s4 ,x 0 probably nev] out ( 8 ?\ghts1 wak+ or sleep+2 :5 at "w x 0 ! *ief object ( 8 lab\rs1 & :5 on a pleasure p>ty he 0 ready to cat* at ! slighte/ clue1 9 ! motion ( a w9d-vane on a boat1 :i* might help him to ! solution4 ,sid5ote3 ,results ( discov]y4 ,! discov]y ( ab]ration made ,bradley fam\s at a b\nd4 ,ox=d might well be pr\d ( h] two ,savilian ,pr(essors at ?is "t1 = !y _h bo? made _w-fam\s discov]ies--,halley t ( ! p]iodicity ( comets1 & ,bradley ( ! ab]ration ( light4 ,h[ diff]5t _! ta/es 7 & h[ difficult x w\ld h be5 = ei!r to d ! "w ( ! o!r6 ,bradley 0 no great ma!matician1 & ?\gh he 0 q able to calculate ! orbit ( a comet1 & c>ri$ on su* "w :5 ,halley left x1 x 0 probably n cong5ial to him4 ,halley1 on ! o!r h&1 almo/ despis$ accurate obs]vations z f9ick+4 ,be sure y are correct to a m9ute1 he 0 wont to say1 & ! fractions d n s mu* matt]4 ,) su* a precept ,bradley w\ld nev] h made 8 discov]ies4 ,no quantity 0 too small 9 8 eyes1 & no soon] 0 ! explanation ( ab]ration satisfactorily e/abli%$ ?an he p]ceiv$ t ?\gh x w\ld acc\nt = ! ma9 facts1 x w\ld n expla9 all4 ,!re 0 some?+ left4 ,?is is (t5 ! case 9 ! hi/ory ( sci5ce4 ,a few ye>s ago x 0 ?\ght t we knew ! con/itution ( our air completely--oxyg51 nitrog51 wat] vap\r1 & c>bonic acid gas2 b a great physici/1 ,"l ,rayleigh1 f\nd t aft] extract+ all ! wat] & c>bonic acid gas1 all ! oxyg5 & all ! nitrog51 !re 0 some?+ left--a v m9ute residuum1 :i* a c>eless exp]im5t] w\ld h ov]look$ or neglect$1 b :i* a true inve/igator l ,"l ,rayleigh saw ! imm5se importance (4 ,he kept 8 eye on t some?+ left1 & pres5tly discov]$ a new gas :i* we n[ "k z argon4 ,_h he repeat$ ! process1 extract+ all ! argon aft] ! nitrog51 he might h f\nd by a scrut9y mu* m accurate /ill yet ano!r gas1 helium1 :i* we n[ "k to exi/ 9 extremely m9ute quantities 9 ! air4 ,b meantime ?is discov]y 0 made 9 ano!r way4 ,sid5ote3 ,/ill some?+ to be expla9$4 ,sid5ote3 ,probably nutation4 ,sid5ote3 ,8 n9ete5 ye>s' campaign4 ,:5 ,bradley _h extract$ all ! ab]ration f 8 obs]vations he f\nd t !re 0 some?+ left1 ano!r problem to be solv$ & "s m ?9k+ to be done to solve x4 ,b he 0 n[ able to pr(it by 8 previ\s lab\rs1 & ! second /ep 0 made m easily ?an ! fir/4 ,! residuum 0 n ! p>allax ( :i* he _h orig9ally be5 9 se>*1 = x did n complete a cycle )9 ! ye>2 x 0 r a progressive *ange f ye> to ye>4 ,b !re 0 an important clue ( ano!r k9d4 ,he saw t ! app>5t movem5ts ( all />s 7 9 ?is case ! same2 & he knew t a movem5t ( ?is k9d c be ref]r$1 n to ! />s !mselves1 b to ! plumb-l9e f :i* _! directions are measur$4 ,he _h ?\ght out ! possible causes ( su* a movem5t ( ! plumb-l9e or ( ! e>? itself1 & _h realis$ t !re might be a nutation :i* w\ld g ?r\gh a cycle 9 ab\t n9ete5 ye>s1 ! p]iod 9 :i* ! moon's nodes revolve4 ,he 0 n ma!matician en\gh to "w out ! cause completely1 b he saw cle>ly t to trace ! :ole effect he mu/ cont9ue ! obs]vations = n9ete5 ye>s2 & accord+ly he ent]$ on ?is long campaign )\t any hesitation4 ,8 in/rum5t 0 /ill t 9 8 aunt's h\se at ,wan/$1 :]e he cont9u$ to live & make ! obs]vations = a few ye>s1 b 9 #agcb he remov$ to ,ox=d1 z we %all see1 & he mu/ h made _m j\rneys betwe5 ,wan/$ & ,ox=d 9 ! c\rse ( ! rema9+ fifte5 ye>s dur+ :i* he cont9u$ to trace out ! effects ( nutation4 ,8 aunt too left ,wan/$ to accompany ,bradley to ,ox=d1 & ! h\se pass$ into o!r h&s4 ,x is to ! la/+ cr$it ( ! new occupant1 ,mrs4 ,elizabe? ,williams1 t ! great a/ronom] 0 all[$ to g on & complete ! valuable s]ies ( obs]vations :i* he _h comm5c$4 ,bradley 0 n lodg$ 9 h] h\se2 he /ay$ ) a fri5d close by on 8 visits to ,wan/$1 b came freely 9 & out ( 8 aunt's old home to make 8 obs]vations4 ,h[ _m ( u are !re :o w\ld *e]fully all[ an a/ronom] to ent] our h\se at any h\r ( ! night to make obs]vations 9 ! coal-cell>6 ,x says mu*1 n only = ,bradley's fame1 b = 8 p]sonal attractiv5ess1 t he %\ld h secur$ ?is p]mission1 & t !re %\ld be no record ( any friction dur+ ^! fifte5 ye>s4 ,at ! end ( ! :ole s]ies ( n9ete5 ye>s 8 conclusions 7 abundantly v]ifi$1 & 8 second great discov]y ( nutation 0 e/abli%$4 ,hon\rs 7 %[]$ ^u him1 & no d\bt ! g5tle he>t ( ,mrs4 ,elizabe? ,williams 0 uplift$ at ! glori\s outcome ( h] long =be>ance4 ,sid5ote3 ,resid5ce at ,ox=d4 ,b we may n[ turn = a few mom5ts f ,bradley's sci5tific "w to 8 daily life4 ,we h said t 9 #agcb1 aft] hold+ 8 pr(essor%ip = elev5 ye>s1 he fir/ w5t def9itely to reside 9 ,ox=d4 ,he actually _h n be5 able to af=d x previ\sly4 ,8 income 0 only ,l#adj a ye>1 & ! /atutes prev5t$ him f hold+ a liv+3 s t he 0 fa9 to accept ,mrs4 ,p\nd's hospitable %elt]4 ,b 9 #agbi an opportunity ( add+ to 8 income pres5t$ itself1 by giv+ lectures 9 exp]im5tal philosophy4 ,! obs]vations on nutation 7 n l ^? on ab]ration3 he 0 n occupi$ day & night try+ to f9d ! solution3 he _h practically made up 8 m9d ab\t ! solution1 & ! actual obs]vations 7 to g on 9 a quiet me?odical mann] = n9ete5 ye>s1 s t he n[ _h leisure to look ab\t him = o!r employm5t4 ,dr4 ,keill1 :o _h be5 ,pr(essor ( ,a/ronomy be=e ,bradley1 _h attract$ l>ge classes to lectures1 n on a/ronomy1 b on exp]im5tal philosophy3 b _h sold 8 app>atus & goodwill to ,mr4 ,:iteside1 ( ,*ri/ ,*ur*1 "o ( ! c&idates :o 7 disappo9t$ by ,bradley's election4 ,9 #agbi ,bradley pur*as$ ! app>atus f ,:iteside1 & began to give lectures 9 exp]im5tal philosophy4 ,8 discov]y ( ab]ration _h made him fam\s1 s t 8 classes 7 l>ge f ! fir/1 & paid him consid]able fees4 ,sudd5ly !re=e he *ang$ 8 pov]ty = a com=table income1 & he 0 able to live 9 ,ox=d 9 "o ( two r$ brick h\ses 9 ,new ,college ,lane1 :i* 7 9 ^? days assign$ to ! ,savilian ,pr(essors 7n[ inhabit$ by ,new ,college und]graduates74 ,8 aunt1 ,mrs4 ,p\nd1 to :om he 0 devot$ly atta*$1 came ) him1 & two ( h] nephews4 ,9 8 "t ( prosp]ity ,bradley 0 ?us able to return ! hospitality :i* _h be5 s g5]\sly af=d$ him 9 times ( /ress4 ,sid5ote3 ,a/ronom] ,royal at ,gre5wi*4 ,sid5ote3 ,lett] f ,e>l ( ,macclesfield4 ,be=e he complet$ 8 obs]vations = nutation ano!r great *ange 9 8 =tunes took place4 ,9 #agdb he 0 elect$ to succe$ ,halley z ,a/ronom] ,royal4 ,x 0 ,halley's dy+ wi% t ,bradley %\ld succe$ him1 & x is said t he 0 ev5 will+ to resign 9 8 fav\r1 = 8 "r h& _h be5 attack$ by p>alysis1 & ! disease 0 gradually spread+4 ,b he di$ )\t any positive assurance t 8 wi% w\ld be fulfill$4 ,! *ief difficulty 9 secur+ ! appo9tm5t ( ,bradley seems to h be5 t he 0 ! obvi\s man = ! po/ 9 univ]sal op9ion4 ,x is n only my fri5d%ip = ,mr4 ,bradley t makes me s ard5tly wi% to see him possess$ ( ! position1 wrote ! ,e>l ( ,macclesfield to ! ,"l ,*ancellor2 x is my real conc]n = ! hon\r ( ! nation ) reg>d to sci5ce4 ,= z our cr$it & reputation h hi!rto n be5 inconsid]able among/ ! a/ronomical "p ( ! _w1 ,i %\ld be extremely sorry we %\ld =feit x all at once by be/[+ ^u a man ( inf]ior skill & abilities ! mo/ hon\rable1 ?\gh n ! mo/ lucrative1 po/ 9 ! pr(ession 7a po/ s well fill$ by ,dr4 ,halley & 8 pr$ecessor71 :5 at ! same "t we h among/ u a man kn[n by all ! =eign1 z well z our own a/ronom]s1 n to be inf]ior to ei!r ( !m1 & "o :om ,sir ,isaac ,newton 0 pleas$ to call ! be/ a/ronom] 9 ,europe4 ,& aga91 ,z ,mr4 ,bradley's abilities 9 a/ronomical le>n+ are all[$ & confess$ by all1 s 8 "* 9 e respect is s well e/abli%$1 & s unblemi%$1 t ,i may defy ! wor/ ( 8 enemies 7if s good & wor?y a man h any7 to make ev5 ! l[e/ or mo/ trifl+ objection to x4 ,aft] all1 ! lett] goes on1 x may be said if ,mr4 ,bradley's skill is s univ]sally ackn[l$g$1 & 8 "* s e/abli%$1 !re is little dang] ( opposition1 s9ce no competitor c ent]ta9 ! lea/ hope ( success aga9/ him4 ,b1 my "l1 we live 9 an age :5 mo/ m5 h[ little soev] _! m]it may be1 seem to ?9k !mselves fit = :atev] !y c get1 & (t5 meet ) "s p1 :o by _! recomm5dations ( !m appe> to ent]ta9 ! same op9ion ( !m1 & x is = ?is reason t ,i am s press+ ) y\r lord%ip n to lose any "t4 ,su* recomm5dations _h1 h[ev]1 _! effect3 ! dread$ possibility ( a misc>riage ( ju/ice 0 av]t$1 & ,bradley became ! ?ird ,a/ronom] ,royal1 ?\gh he did n resign 8 pr(essor%ip at ,ox=d4 ,halley1 ,bradley1 & ,bliss1 :o 7 ,a/ronom]s ,royal 9 succession1 all held ! appo9tm5t along ) "o ( ! ,savilian pr(essor%ips at ,ox=d2 b s9ce ! dea? ( ,bliss 9 #agfa1 ! appo9tm5t has always gone to a ,cambridge man4 ,sid5ote3 ,in/rum5ts v defective4 ,:5 ,bradley w5t to ,gre5wi*1 9 ,june #agdb1 he 0 at fir/ unable to d mu* f ! wret*$ /ate 9 :i* he f\nd ! in/rum5ts4 ,halley 0 n a good obs]v]3 8 he>t 0 n 9 ! "w1 & he _h n tak5 ! tr\ble to set ! in/rum5ts "r :5 !y w5t wrong4 ,! c\nt]poises ( t in/rum5t :i* ought to h be5 ! be/ 9 ! _w at ! "t rubb$ aga9/ ! ro( s t ! telescope c\ld sc>cely be mov$ 9 "s positions3 & "s ( ! screws 7 brok54 ,!re 0 no prop] means ( illum9at+ ! cross-wires1 & s on4 ,) c>e & pati5ce ,bradley set all ?is "r1 & began obs]vations4 ,he _h ! good =tune to secure ! help ( 8 nephew1 ,john ,bradley1 z assi/ant1 & ! companion%ip seems to h be5 z happy z t previ\s "o ( ,james ,bradley & 8 uncle ,p\nd4 ,john ,bradley 0 able to c>ry on ! obs]vations :5 8 uncle 0 abs5t 9 ,ox=d1 & ! "w ! two got ?r\gh toge!r 9 ! fir/ ye> is 79 ! words ( ,bradley's biograph] ,rigaud7 sc>cely to be cr$it$4 ,! transit obs]vations occupy #agg folio pages1 & no less ?an #bee obs]vations 7 tak5 on "o night4 ,& at ! same "t1 x mu/ be rememb]$1 ,bradley 0 /ill c>ry+ on 8 nutation obs]vations at ,wan/$1 /ill lectur+ at ,ox=d1 & n cont5t ) all ?is1 began a c\rse ( exp]im5ts on ! l5g? ( ! seconds' p5dulum4 ,truly a giant = h>d "w6 ,sid5ote3 ,new in/rum5ts4 ,b1 9 spite ( 8 c>e 9 sett+ !m "r1 ! in/rum5ts 9 ! ,obs]vatory 7 f\nd to be hopelessly defective4 ,! hi/ory ( ! in/rum5ts at ! ,royal ,obs]vatory is a curi\s "o4 ,:5 ,flam/e$ 0 appo9t$ ! fir/ ,a/ronom] ,royal he 0 giv5 ! magnific5t sal>y ( ,l#ajj a ye>1 & no in/rum5ts to obs]ve )4 ,he pur*as$ "s in/rum5ts ) 8 own money1 & at 8 dea? !y 7 claim$ by 8 executors4 ,h5ce ,halley1 ! second ,a/ronom] ,royal1 f\nd ! ,obs]vatory totally unprovid$ 9 ?is respect4 ,he manag$ to p]suade ! nation to furni% ! funds = an equipm5t2 b ,halley1 ?\gh a man ( great ability 9 o!r ways1 did n "k a good in/rum5t f a bad "o2 s t ,bradley's fir/ few ye>s at ! ,obs]vatory 7 wa/$ ow+ to ! imp]fection ( ! equipm5t4 ,:5 ?is 0 fully realis$ he ask$ = funds to buy new in/rum5ts1 & su* 0 ! confid5ce felt 9 him t he got :at he ask$ = )\t mu* difficulty4 ,m ?an ,l#ajjj1 a l>ge sum = ^? days1 0 sp5t "u 8 direction1 ! pr9cipal pur*ases be+ two quadrants = obs]vation ( ! position ( ! />s1 "o to ! nor? & ! o!r to ! s\?4 ,) ^! quadrants1 :i* repres5t$ ! p]fection ( su* app>atus at t "t1 ,bradley made t long & wond]ful s]ies ( obs]vations :i* is ! />t+-po9t ( our k ( ! movem5ts ( ! />s4 ,! in/rum5ts are /ill 9 ! ,royal ,obs]vatory1 ! m important ( ! two 9 its orig9al position z ,bradley m\nt$ x & left x4 ,sid5ote3 ,"w at ,gre5wi*4 ,x seems ne$less to m5tion 8 "w z ,a/ronom] ,royal1 b ,i w give q briefly a summ>y ( :at he accompli%$1 & !n recall a p>ticul> incid5t1 :i* %[s h[ f> ahead ( 8 g5]ation 8 g5ius = obs]vation plac$ him4 ,! summ>y may be giv5 z foll[s4 ,we owe to ,bradley-- #a4 ,a bett] k ( ! movem5ts ( ,jupit]'s satellites4 #b4 ,! orbits ( sev]al comets calculat$ directly f 8 own obs]vations1 :5 su* "w 0 new & difficult4 #c4 ,exp]im5ts on ! l5g? ( ! p5dulum4 #d4 ,! f\ndation ( our k ( ! refraction ( our atmosph]e4 #e4 ,consid]able improvem5ts 9 ! tables ( ! moon1 & ! promotion ( ! me?od = f9d+ ! longitude by lun> di/ances4 #f4 ,! prop] equipm5t ( our national ,obs]vatory ) in/rum5ts1 & ! use ( ^! to =m ! basis ( our pres5t k ( ! positions & motions ( ! />s4 ,_m m5 w\ld consid] any "o ( ^! six a*ievem5ts by itself a suffici5t title to fame4 ,bradley accompli%$ !m all 9 addition to 8 great discov]ies ( ab]ration & nutation4 ,sid5ote3 ,might h f\nd v>iation ( latitude4 ,& ) a little m opportunity he might h add$ ano!r great discov]y :i* has %$ lu/re on ! "w ( ! la/ decade4 ,we said e>li] 9 ?is *apt] t ! axis ( ! e>? may move 9 "o or two ways4 ,ei!r x may po9t to a diff]5t />1 rema9+ fix$ relatively to ! e>?1 z 9 ! nutation :i* ,bradley discov]$2 or x may actually *ange its position 9 ! e>?4 ,?is second k9d ( movem5t 0 believ$ until tw5ty ye>s ago n to exi/ appreciably2 b ! "w ( ,kue/n] & ,*&l] l$ to ! discov]y t x did exi/1 & its complexities h be5 unravell$1 & w be consid]$ 9 ! six? *apt]4 ,n[ a c5tury & a half ago ,bradley 0 on ! track ( ?is v>iation ( latitude4 ,8 c>eful obs]vations actually %[$ ! motion ( ! pole1 z ,mr4 ,*&l] has rec5tly demon/rat$2 &1 moreov]1 ,bradley himself notic$ t !re 0 some?+ unexpla9$4 ,once aga9 !re 0 a residuum aft] 7fir/7 ab]ration & 7next7 nutation _h be5 extract$ f ! obs]vations2 & ) long] life he might h expla9$ ?is residuum1 & add$ a ?ird great discov]y to ! previ\s two4 ,or ano!r com+ aft] him might h f\nd x2 b aft] ! giant came m5 :o c\ld n tread 9 8 foot/eps1 & ! _w wait$ #aej ye>s be=e ! discrepancy 0 expla9$4 ,sid5ote3 ,ox=d's t>dy recognition ( ,bradley4 ,! attitude ( our lead+ univ]sities t[>ds sci5ce & sci5tific m5 is ( suffici5t importance to ju/ify ano!r glance at ! relations betwe5 ,bradley & ,ox=d4 ,we h se5 t ,ox=d's treatm5t ( ,bradley 0 n altoge!r satisfactory4 ,%e left him to le>n a/ronomy z he be/ c\ld1 & he owes no tea*+ to h]4 ,%e made him ,pr(essor ( ,a/ronomy1 b gave him no obs]vatory & a begg>ly income :i* he _h to supplem5t by giv+ lectures on a diff]5t subject4 ,b :5 he _h disreg>d$ ^! disc\ragem5ts & made a "n = himself1 ,ox=d took h] %>e 9 recognition4 ,he 0 creat$ ,d4,d4 by diploma 9 #agdb2 & :5 8 discov]y ( nutation 0 ann\nc$ 9 #agdh1 & produc$ di/9ctions & hon\rs ( all k9ds f ov] ! _w1 we are told t amid/ all ^! di/9ctions1 wide z ! range ( mod]n sci5ce1 & p]man5t z its hi/ory1 !re 0 "o :i* probably came ne>] 8 he>t1 & 0 /ill m gratify+ to 8 feel+ ?an all4 ,l[? 7aft]w>ds ,bi%op ( ,london71 a popul> man1 an elegant s*ol>1 & possess$ ( consid]able eloqu5ce1 _h 9 #agea to make 8 la/ spee* 9 ! ,%eldonian ,!atre at ,ox=d z ,pr(essor ( ,poetry4 ,9 record+ ! b5efits = :i* ! ,univ]sity 0 indebt$ to its b5efactors1 he m5tion$ ! names ( ^? :om ,sir ,h5ry ,savile's f\ndation _h e/abli%$ !re3 ',:at m5 ( le>n+6 :at ma!maticians6 we owe to ,savile1 ,briggs1 ,wallis1 ,halley2 to ,savile we owe ,greaves1 ,w>d1 ,wr51 ,gregory1 ,keill1 & "o :om ,i w n "n1 = po/]ity w ev] h 8 "n on its lips4' ,bradley 0 himself pres5t2 !re 0 no "o 9 ! cr[d$ assembly on :om ! allusion 0 lo/1 or :o did n feel ! tru? & ju/ice ( x2 all eyes 7 turn$ to him1 :ile ! walls rung ) %\ts ( he>tfelt affection & admiration2 x 0 l ! triumph ( ,!mi/ocles at ! ,olympic games4 ,sid5ote3 ,! /udy ( residual ph5om5a4 ,^! words ( ,rigaud indicate ! fame des]v$ly acquir$ by an e>ne/ & simple-m9d$ devotion to sci5ce3 b c we le>n any?+ f ! /udy ( ,bradley's "w to guide u 9 fur!r rese>*8 ,! *ief lessons w\ld seem to be t if we make a s]ies ( c>eful obs]vations1 we %all probably f9d "s deviation f expectation3 t we mu/ foll[ up ?is clue until we h f\nd "s explanation :i* fits ! facts1 n be+ disc\rag$ if we _c hit ^u ! explanation at once1 s9ce ,bradley himself 0 puzzl$ = sev]al ye>s3 t aft] f9d+ "o v]a causa1 & all[+ = ! effect ( x1 ! obs]vations may %[ traces ( ano!r :i* mu/ aga9 be pati5tly hunt$1 ev5 ?\gh we sp5d n9ete5 ye>s 9 ! *ase3 & t aga9 we may h to leave ! complete rectification ( ! obs]vations to po/]ity4 ,b ?\gh we may admit ! g5]al helpfulness ( ^! directions1 & t ?is pati5t deal+ ) residual ph5om5a seems to be a me?od capable ( frequ5t application1 we _c d$uce any univ]sal pr9ciple ( proc$ure f !m3 witness ! difficulty ( deal+ ) meteorological obs]vations1 = in/ance4 ,x is n always possible to f9d any ord]ly arrangem5t ( ! residuals :i* w give u a clue to />t )4 ,:5 su* an arrangem5t is manife/$1 we mu/ c]ta9ly foll[ up ! clue2 x w\ld almo/ seem t no exp5se %\ld be prohibitive1 s9ce x is impossible to =esee ! importance ( ! result4 ,,*apt] ,,iv ,,accid5tal ,,discov]ies ,sid5ote3 ,! ,ox=d new /> f\nd dur+ "w on ,a/rographic ,*>t4 ,9 review+ v>i\s types ( a/ronomical discov]y ,i h laid "s /ress ^u ! fact t !y are1 g5]ally speak+1 f> f be+ accid5tal 9 "*4 ,a new planet does n swim into our k51 at any rate n usually1 b is f\nd only aft] dilig5t se>*1 & !n only by an inve/igator ( acute vision1 or o!r special qualifications4 ,b ?is is1 ( c\rse1 n always ! case4 ,"s discov]ies are made by ! m]e/ accid5t1 z we h _h occasion to rem>k incid5tally 9 ! case ( ! m9or planets2 & = ! sake ( complet5ess x is desirable to include among our types at lea/ "o case ( su* accid5tal discov]y4 ,z1 h[ev]1 ! selection is a little invidi\s1 ,i may p]haps be p>don$ = tak+ ! in/ance f my own exp]i5ce1 :i* happ5s to include a case :]e "o ( ^? rem>kable objects call$ new />s walk$ delib]ately into a net spread = totally diff]5t objects4 ,!re is ! fur!r reason = *oos+ ?is in/ance3 t x w af=d me ! opportunity ( say+ some?+ ab\t ! special rese>* 9 :i* we 7 actually engag$1 ! "w ( mapp+ out ! heav5s by photography1 or1 z x has be5 call$1 ! ,a/rographic ,*>t--a great s*eme ( int]national co-op]ation by :i* x is hop$ to leave z a legacy = future c5turies a record ( ! /ate ( ! sky 9 our age4 ,su* a record _c be complete2 = h[ev] fa9t ! />s includ$1 we "k t !re are fa9t] />s :i* might h be5 includ$ _h we giv5 long] exposures to ! plates4 ,nor c x be 9 o!r ways f9al or p]fect2 h[ev] l>ge ! scale1 = in/ance1 on :i* ! map is made1 we c imag9e ! scale d\bl$ or increas$ _m-fold4 ,b ! map w be a great advance on any?+ t has hi!rto be5 made1 & "s acc\nt ( x w !re=e no d\bt be ( int]e/4 ,sid5ote3 ,orig9 ( ! *>t4 ,we may p]haps beg9 ) a brief hi/orical acc\nt ( ! ent]prise4 ,photographs ( ! />s 7 tak5 _m ye>s ago1 b only by a few en?usia/s1 & ) no s]i\s hope ( compet+ ) eye obs]vations ( ! sky4 ,! old wet-plate photography 01 9 fact1 some:at unsuit$ to a/ronomical purposes2 to photograph fa9t objects a long exposure is necess>y1 & ! wet plate may dry up be=e ! exposure is conclud$--nay1 ev5 be=e x is comm5c$1 if ! obs]v] has to wait = pass+ cl\ds--& !re=e x may be said t ! successful application ( photography to a/ronomy dates f ! "t :5 ! dry plate 0 inv5t$2 :5 x became possible to expose a plate 9 ! telescope = h\rs1 or by accumulation ev5 = days4 ,! dry plate rema9s s5sitive = a long p]iod1 & if x is desir$ to ext5d an exposure beyond ! limits ( "o night1 x is q easy to close up ! telescope & return to ! op]ations aga9 on ! next f9e night2 & s on1 if n p]haps indef9itely1 at any rate s long z to transc5d ! limits ( human pati5ce up to ! pres5t4 ,illu/ration3 ,,vii4--,,great ,,comet ,,( ,,nov4 #g,,?1 #ahhb 7,f a photograph tak5 at ! ,royal ,obs]vatory1 ,cape ( ,good ,hope47 ,sid5ote3 ,comet ( #ahhb4 ,sid5ote3 ,/>s %[n on ! pictures4 ,b to consid] our p>ticul> project4 ,we may assign1 p]haps1 ! date #ahhb z t 9 :i* x fir/ began to take %ape4 ,9 t ye> !re 0 a magnific5t bright comet1 ! la/ really l>ge comet :i* we1 9 ! ,nor!rn ,hemisph]e1 h _h ! good =tune to see4 ,"s ( u1 ( c\rse1 7 n born at t "t1 & p]haps o!rs :o 7 alive may nev]!less n h se5 t comet2 = x kept some:at uncom=tably e>ly morn+ h\rs1 & ,i c well rememb] myself feel+ r m res5tm5t ?an gratitude to ! man :o wak$ me up ab\t f\r o'clock to see x4 ,_m obs]vations 7 ( c\rse made ( ?is int]e/+ visitor1 & :at specially conc]ns u is t at ! ,cape ( ,good ,hope "s ent]pris+ photograph]s tri$ to photograph x4 ,!y tri$ 9 ! fir/ in/ance ) ord9>y cam]as1 & soon f\nd--:at any a/ronom] c\ld h told !m--t ! movem5t ( ! e>?1 caus+ an app>5t movem5t ( ! comet & ! />s 9 ! opposite direction1 fru/rat$ _! ef=ts4 ,! difficulties ( obta9+ pictures ( mov+ objects are famili> to all photograph]s4 ,a snap-%ot might h met ! difficulty1 b ! comet 0 sc>cely bright en\gh to affect ! plate ) a %ort exposure4 ,ultimately ,dr4 ,david ,gill1 ! a/ronom] at ! ,cape ,obs]vatory1 invit$ "o ( ! photograph]s to /rap 8 cam]a to "o ( ! telescopes at ! ,obs]vatory1 a telescope :i* c\ld be c>ri$ r\nd by clockwork 9 ! usual way1 s z to c\nt]act ! e>?'s motion1 & 9 effect to keep ! comet /eadily 9 view1 z ?\gh x 7 at re/4 ,z a consequ5ce1 "s v beautiful & successful pictures ( ! comet 7 obta9$1 & on !m a l>ge numb] ( />s 7 also %[n4 ,!y 71 z ,i h said1 n by any means ! fir/ pictures ( />s obta9$ by photography1 b !y repres5t$ 9 facility & 9 success s great an advance ^u :at _h be5 =m]ly obta9$ t !y attract$ consid]able att5tion4 ,!y 7 s5t to ,europe & /imulat$ v>i\s work]s to fur!r exp]im5ts4 ,sid5ote3 ,! bro!rs ,h5ry beg9 "w4 ,sid5ote3 ,conf]5ce ( #ahhg4 ,! late ,dr4 ,common 9 ,engl&1 an amateur a/ronom]1 began t magnific5t pione] "w 9 a/ronomical photography :i* soon br\ght him ! ,gold ,m$al ( ! ,royal ,a/ronomical ,society = 8 photographs ( nebulae4 ,b ! mo/ important result = our purpose 0 produc$ 9 ,france4 ,!re _h be5 />t$ _m ye>s be=e by ! ,fr5* a/ronom] ,*acornac a s]ies ( /> maps r\nd ! ,zodiac simil> 9 int5tion to ! ,b]l9 maps :i* figur$ 9 ! hi/ory ( ! discov]y ( ,neptune4 ,*acornac di$ be=e 8 ent]prise 0 v f> advanc$1 & ! "w 0 tak5 up by two bro!rs1 ,paul & ,prosp] ,h5ry1 :o foll[$ ,*acornac 9 adopt+ = ! "w ! labori\s me?od ( eye obs]vation ( ea* individual />4 ,!y proce$$ pati5tly ) ! "w on ^! l9es2 b :5 !y came to ! region :]e ! ,zodiac is cross$ by ! ,milky ,way1 & ! numb] ( />s 9 a giv5 area increases enorm\sly1 !y f\nd ! lab\r s great z to be practically prohibitive1 & 7 9 d\bt h[ to deal ) ! difficulty4 ,x 0 at ?is critical mom5t t ^! comet photographs1 %[+ ! />s s beautifully1 sugge/$ ! alt]native ( mapp+ ! />s photographically4 ,!y imm$iately set to "w ) a trial l5s1 & obta9$ su* enc\rag+ results t !y proce$$ !mselves to make a l>g] l5s ( ! same type2 ?is aga9 0 satisfactory1 & ! idea naturally arose ( ext5d+ to ! :ole heav5s ! s*eme :i* !y _h hi!rto int5d$ only = ! ,zodiac1 a m]e belt ( ! heav5s4 ,b ?is r5d]$ ! ent]prise too l>ge = a s+le obs]vatory4 ,x became necess>y to obta9 ! co-op]ation ( o!r obs]vatories1 & ) ?is end 9 view an ,int]national ,conf]5ce 0 summon$ to meet 9 ,p>is 9 #ahhg to consid] ! :ole project4 ,!re 7 delegates f1 if n all nations1 at any rate a consid]able numb]3-- ,france #bj ,briti% ,empire #h ,g]many #f ,russia #c ,holl& #c ,u4,s4 ,am]ica #c ,au/ria #b ,sw$5 #b ,d5m>k #b ,belgium #a ,italy #a ,spa9 #a ,switz]l& #a ,portugal #a ,brazil #a ,arg5t9e ,republic #a ,sid5ote3 ,*oice ( in/rum5t4 ,sid5ote3 ,exp5se ( d\blet4 ,sid5ote3 ,advantages ( reflector4 ,sid5ote3 ,refractor *os54 ,! ,conf]5ce _h a numb] ( v important que/ions to discuss1 = k ( ! photographic me?od & its possibilities 0 at t "t 9 its infancy4 ,!re 01 = in/ance1 ! "q :e!r all ! in/rum5ts ne$ be ( ! same patt]n1 & if s :at t patt]n %\ld be4 ,! fir/ ( ^! que/ions 0 settl$ 9 ! affirmative1 z we might expect2 9 ! int]e/s ( uni=mity x 0 desirable t ! maps %\ld be z ne>ly simil> z possible4 ,! second "q 0 n s easy2 !re 7 at lea/ ?ree diff]5t types ( in/rum5ts :i* might be us$4 ,fir/ ( all1 !re 0 ! photographic l5s1 su* z is famili> to all :o h us$ an ord9>y cam]a1 consi/+ ( two l5ses ) a space betwe52 ?\gh s9ce ea* ( ^! l5ses is itself made up ( two1 we %\ld m correctly say f\r l5ses 9 all4 ,x 0 ) a l5s ( ?is k9d t ! comet pictures _h be5 tak5 at ! ,cape ( ,good ,hope1 & x might seem ! safe/ plan to adopt :at _h be5 %[n to be capable ( su* good "w4 ,b !re 0 ?is difficulty2 ! pictures ( ! comet 7 on a v small scale1 & tak5 ) a small l5s2 a mu* l>g] l5s 0 requir$ = ! s*eme n[ "u contemplation1 & :5 !re are f\r sep>ate l5ses to be made1 ea* ) two surfaces to poli%1 & ea* requir+ a p]fectly s\nd cle> piece ( glass1 x w be obvi\s t ! difficulties ( mak+ a l>ge comp\nd l5s ( ?is k9d are mu* great]1 & ! exp5se mu* m s]i\s ?an 9 ! case ( a s+le l5s1 or ev5 a pair4 ,x 0 ?is "q ( exp5se :i* _h l$ ! bro!rs ,h5ry to exp]im5t ) a diff]5t k9d ( in/rum5t1 9 :i* only "o pair ( l5ses 0 us$ in/ead ( two4 ,_! in/rum5t 01 9 fact1 v simil> to ! ord9>y telescope1 except+ t !y 7 b\nd to make _! l5ses some:at diff]5t 9 %ape 9 ord] to br+ to focus ! rays ( light suitable = photography1 :i* are n ! same z ^? suitable = eye obs]vation ) ! ord9>y telescope4 ,dr4 ,common1 aga91 _h us$ a ?ird k9d ( in/rum5t1 ma9ly ) ! view ( r$uc+ ! necess>y exp5se /ill fur!r1 or1 p]haps1 ( increas+ ! size ( ! in/rum5t = ! same exp5se4 ,8 telescope _h no l5s at all1 b a curv$ mirror in/ead1 ! mirror be+ made ( glass silv]$ on ! face 7n on ! back z 9 ! ord9>y look+-glass74 ,9 ?is case !re is only "o surface to poli% in/ead ( f\r1 z 9 ! ,h5rys' telescope1 or eight1 z 9 ! case ( ! photographic d\blet2 &1 moreov]1 s9ce ! rays ( light are reflect$ f ! surface ( ! glass1 & d n pass ?r\gh x at all1 ! int]nal /ructure ( ! glass is n s /rictly important z 9 ! o!r cases4 ,h5ce ! reflector is a v *eap in/rum5t1 & x is1 moreov]1 q free f "s difficulties atta*$ to ! o!r in/rum5ts4 ,no correction = rays ( light ( diff]5t col\rs is requir$1 s9ce all rays ( :atev] col\r come to ! same focus automatically4 ,^! advantages ( ! reflector 7 s consid]able z to almo/ outweigh "o well-kn[n disadvantage1 :i* is1 h[ev]1 n v easily express$ 9 words4 ,! reflector might be describ$ z an in/rum5t ) a temp]2 sometimes x gives excell5t results1 b at o!rs some?+ seems to be wrong1 ?\gh ! worri$ obs]v] does n exactly "k :at4 ,long exp]i5ce & pati5ce are requisite to hum\r ! in/rum5t & get ! be/ results f x1 & x 0 felt t ?is unc]ta9ty 0 suffici5t to disqualify ! in/rum5t = ! s]i\s piece ( r\t9e "w contemplat$ 9 mapp+ ! heav5s4 ,accord+ly ! h&i] & m amiable in/rum5t ) :i* ! bro!rs ,h5ry _h done su* good "w 0 select$ z ! patt]n to be adopt$4 ,sid5ote3 ,d\blet w\ld h be5 bett]4 ,x is curi\s t at ! ,conf]5ce ( #ahhg no?+ at all 0 said ab\t ! type ( in/rum5t fir/ m5tion$ 7! d\blet l5s71 al?\gh a lett] 0 writt5 9 its fav\r by ,pr(essor ,pick]+ ( ,h>v>d ,college ,obs]vatory4 ,s9ce t "t we h le>nt mu* ( its advantages1 & x is probable t if ! ,conf]5ce 7 to meet n[ !y might arrive at a diff]5t decision2 b at t "t !y 71 to put x briefly1 some:at afraid ( an in/rum5t :i* seem$ to promise1 if any?+1 too well1 especially 9 "o respect4 ,) ! reflector & ! refractor x _h be5 f\nd t ! field ( good images 0 /rictly limit$4 ,! ,h5rys' telescope w\ld n photograph an area ( ! sky great] 9 ext5t ?an #b deg4 9 diamet] at any "o "t1 & ! reflector 0 m limit$ /ill2 )9 ?is area ! images ( ! />s 7 good1 & x _h be5 f\nd t _! places 7 accurately repres5t$4 ,n[ ! d\blet seem$ to be able to %[ mu* l>g] areas ?an ?is ) accuracy1 b no "o _h be5 able to te/ ! accuracy to see :e!r x 0 suffici5t = a/ronomical purposes2 & al?\gh no su* feel+ 0 op5ly express$ or is on record1 ,i ?9k !re is no d\bt t a feel+ exi/$ ( g5]al mi/ru/ ( an in/rum5t :i* seem$ to (f] su* speci\s promises4 ,:atev] ! reason1 its claims 7 pass$ ov] 9 sil5ce at ! ,conf]5ce1 & ! saf] l9e 7z x 0 !n ?\ght7 ( adopt+ z ! type ! ,h5rys' in/rum5t1 0 tak54 ,sid5ote3 ,! eighte5 obs]vatories4 ,?is 0 p]haps ! mo/ important "q settl$ at ! ,conf]5ce1 & ! answ]s to _m ( ! o!rs naturally foll[$4 ,! size ( ! plates1 = in/ance1 0 settl$ automatically4 ,! "q d[n to :at degree ( fa9tness %\ld />s be includ$1 resolv$ itself into ! equival5t "q1 ,:at %\ld be ! l5g? ( "t dur+ :i* ! plates 7 expos$8 ,!n1 aga91 ! "q1 ,:at obs]vatories %\ld take "p 9 ! "w8 became simply ?is3 ,:at obs]vatories c\ld af=d to acquire ! in/rum5ts ( ?is new patt]n & get o!r funds = c>ry+ out ! "w specifi$8 ,x 0 ultimately f\nd t eighte5 obs]vatories 7 able to obta9 ! app>atus & funds1 ?\gh un=tunately ?ree ( ! eighte5 h s9ce f\nd x impossible to proce$4 ,! foll[+ is ! orig9al li/1 & 9 brackets are add$ ! names ( ?ree o!r obs]vatories :i* 9 #aijj und]took to fill ! places ( ! default]s4 ,,obs]vatories ,,co-,,op]at+ ,,= ,,! ,,a/rographic ,,*>t4 ---------------------------------------- ---- ,obs]vatory4 ,zones ( ,numb] ,decl9ation4( ,plates4 ---------------------------------------- ---- ,gre5wi* #ij deg4 to #fe deg4 #aadi ,rome #fd deg4 #ee deg4 #aadj ,catania #ed deg4 #dg deg4 #ajjh ,hels+=s #df deg4 #dj deg4 #ajjh ,potsdam #ci deg4 #cb deg4 #abcb ,ox=d #ca deg4 #be deg4 #aahj ,p>is #bd deg4 #ah deg4 #abfj ,bordeaux #ag deg4 #aa deg4 #abfj ,t\l\se #aj deg4 #e deg4 #ajhj ,algi]s #d deg4 - #b deg4 #abfj ,san ,f]n&o - #c deg4 - #i deg4 #abfj ,tacubaya -#aj deg4 -#af deg4 #abfj ,santiago 7,monte ,video7-#ag deg4 -#bc deg4 #abfj ,la ,plata 7,cordoba7 -#bd deg4 -#ca deg4 #acfj ,rio 7,p]?1 ,au/ralia7-#cb deg4 -#dj deg4 #acgf ,cape ( ,good ,hope -#da deg4 -#ea deg4 #aeab ,sydney -#eb deg4 -#fd deg4 #adjj ,melb\rne -#fe deg4 -#ij deg4 #aadi ---------------------------------------- ---- ,sid5ote3 ,sky cov]$ twice4 ,9 ! li/ is also %[n ! total numb] ( plates t 7 to be tak5 by ea* obs]vatory4 ,:5 once ! size ( ! plates _h be5 settl$1 x 0 a /raight=w>d matt] to divide up ! sky into ! prop] numb] ( regions necess>y to cov] x completely1 n only )\t gaps betwe5 ! plates1 b ) actually a small ov]lap ( contigu\s plates4 ,& m ?an ?is1 x 0 decid$ t ! :ole sky %\ld be completely cov]$ twice ov]4 ,x 0 conceivable t a "q might arise :e!r an app>5t /> image on a plate 01 on ! "o h&1 a du/ speck1 or1 on ! o!r h&1 a planet1 or p]haps a v>iable or new />4 ,by tak+ two diff]5t plates at slightly diff]5t times1 que/ions ( ?is k9d c\ld be settl$2 & to make ! *eck m indep5d5t x 0 decid$ t ! plates %\ld n be exactly repeat$ on ! same portion ( sky1 b t 9 ! second s]ies ! c5tre ( a plate %\ld occupy ! po9t assign$ to ! corn] ( a plate 9 ! fir/ s]ies4 ,sid5ote3 ,times ( exposure4 ,!n !re came ! important "q ( "t ( exposure1 :i* involv$ a long debate betwe5 ^? :o desir$ ! mo/ mode/ programme possible consi/5t ) effici5cy1 & ^? en?usia/s :o 7 anxi\s to /ra9 ! programme to ! utmo/ limits atta9able4 ,ultimately x 0 resolv$ to take two s]ies ( plates2 "o s]ies ( long exposure :i* 0 set 9 ! fir/ in/ance at #aj m9utes1 !n became #ae1 !n #cj1 !n #dj1 & has by "s ent]pris+ obs]v]s be5 ext5d$ to #a-a_/b h\rs2 ! o!r a s]ies ( %ort exposures :i* h be5 g5]ally fix$ at #f m9utes4 ,?us in/ead ( cov]+ ! sky twice1 x 0 decid$ to cov] x 9 all f\r times1 & ! numb] ( plates assign$ to ea* obs]vatory 9 ! above li/ mu/ be reg>d$ z d\bl$ by ?is new decision4 ,& fur!r /ill1 on ! s]ies ( %ort-exposure plates x 0 decid$ to add to ! exposure ( six m9utes ano!r "o ( ?ree m9utes1 hav+ slightly %ift$ ! telescope betwe5 ! two s t !y %\ld n be sup]impos$2 & lat] /ill1 a ?ird exposure ( tw5ty seconds 0 add$ to ^!4 ,x w\ld take too long to expla9 "h ! reasons = ^! details1 b x w be cle> t ! g5]al result ( ! discussion 0 to ext5d ! orig9al programme consid]ably1 & r5d] ! "w ev5 m labori\s ?an x _h appe>$ at ! outset4 ,sid5ote3 ,measurem5t ( plates4 ,sid5ote3 ,! reseau4 ,sid5ote3 ,! microscope4 ,sid5ote3 ,rev]sal ( plates4 ,sid5ote3 ,p]sonal equation4 ,:5 all ^! plates h be5 tak51 ! "w is by no means f9i%$2 inde$1 x is only j comm5c+4 ,!re rema9s ! task ( measur+ accurately on ea* ( ! %ort-exposure plates ! positions ( ! />s :i* x repres5ts1 numb]+ on ! av]age "s #cjj or #djj2 s t = in/ance at ,ox=d ! total numb] ( />s measur$ on ! twelve hundr$ plates is ne>ly half a million4 ,^! are n all sep>ate />s2 = ! sky is repres5t$ twice ov]1 & !re is also ! slight ov]lap ( contigu\s plates2 b ! numb] ( actual sep>ate />s measur$ at ?is "o obs]vatory is n f> %ort ( a qu>t] ( a million1 & x has tak5 ne>ly t5 ye>s to make ! measurem5ts1 ) ! help ( ?ree or f\r measur]s tra9$ = ! purpose4 ,to r5d] ! measures easy1 a network or reseau ( cross l9es is photograph$ on ea* plate by artificial light aft] x has be5 expos$ to ! />s1 s t on developm5t ^! cross l9es & ! />s bo? appe>4 ,we c see at a glance ! approximate position ( a /> by c\nt+ ! numb] ( ! space f left to "r & f top to bottom 9 :i* x occurs2 & we c also e/imate ! fraction ( a space 9 addition to ! :ole numb]2 b x is necess>y = a/ronomical purposes to e/imate ?is fraction ) ! greate/ exactness4 ,! :ole numb]s are already giv5 ) great exactness by ! c>eful rul+ ( ! cross l9es1 :i* c be spac$ ) extraord9>y p]fection4 ,to measure ! fraction1 we place ! plate "u a microscope 9 ! eye-piece ( :i* !re is a f9ally divid$ cross scale2 ! c5tre ( ! cross is plac$ ov] a /> image1 & !n x is not$ :]e ! l9es ( ! reseau cut ! cross scale4 ,9 ?is way ! position ( ! image ( a /> is read (f ) accuracy1 & aft] a little practice ) consid]able rapidity4 ,x has be5 f\nd at ,ox=d t "u fav\rable conditions ! places ( ne>ly #bjj />s p] h\r c be record$ 9 ?is way by a s+le measur]1 if he has "s "o to write d[n = him ! numb]s he calls out4 ,?is is only "o =m ( measur+ app>atus2 !re are o!rs 9 :i*1 in/ead ( a scale 9 ! eye-piece1 micromet] screws are us$ to measure ! fractions2 b ! g5]al pr9ciple 9 all ^! in/rum5ts is mu* ! same1 & ! rate ( "w is n v diff]5t2 :ile to ! m9or advantages & disadvantages ( ! diff]5t types !re seems no ne$ "h to ref]4 ,"o p>ticul> po9t1 h[ev]1 is wor? not+4 ,aft] a plate has be5 measur$1 x is turn$ r\nd completely1 s t left is n[ "r1 & top is n[ bottom1 & ! measurem5ts are repeat$4 ,?is repetition has ! advantage fir/ ( all ( *eck+ any mi/akes4 ,:5 a long piece ( measur+ or num]ical "w ( any k9d is und]tak5 !re are inv>iably mom5ts :5 ! att5tion seems to w&]1 & "s small error is ! result4 ,b !re are also c]ta9 errors ( a sy/ematic "* simil> to ^? d5ot$ by ! t]m p]sonal equation1 :i* has f\nd its way into o!r walks ( life4 ,9 ! op]ation ( plac+ a cross exactly ov] ! image ( a />1 diff]5t obs]v]s w\ld %[ slight diff]5ces ( habit2 "o might place x a little m to ! "r ?an ano!r4 ,b :5 ! plate is turn$ r\nd ! effect ( ?is habit on ! measure is exactly rev]s$1 & h5ce if we take ! mean ( ! two measures any p]sonal habit ( ?is k9d is elim9at$4 ,x has be5 f\nd by exp]i5ce t su* p]sonal habits are mu* small] = measures ( ?is k9d ?an = ^? to :i* we h long be5 accu/om$ 9 obs]vations made by eye on ! />s !mselves4 ,! tr\bles f p]sonal equation h be5 mu* dim9i%$ by ! photographic me?od1 & c]ta9 peculi>ities ( ! =m] me?od h be5 cle>ly exhibit$ by ! comp>ison4 ,= in/ance1 x has gradually become cle> t ) eye obs]vations p]sonal equation is n a con/ant quantity1 b is diff]5t = />s ( diff]5t brightness4 ,:5 obs]v+ ! transit ( a bright /> ! obs]v] app>5tly records an in/ant def9itely e>li] ?an 9 record+ ! transit ( a fa9t "o2 & ?is peculi>ity seems to be common to ! l>ge majority ( obs]v]s1 :i* is p]haps ! reason :y x 0 n notic$ e>li]4 ,b :5 positions ( ! />s det]m9$ 9 ?is way are comp>$ ) _! positions measur$ on ! photographic plates1 ! peculi>ity is made cle>ly manife/4 ,= example1 at ,ox=d1 our fir/ bus9ess aft] mak+ measurem5ts is to comp>e !m ) visual obs]vations on a limit$ numb] ( ! bright] />s made at ,cambridge ab\t tw5ty ye>s ago4 7,ab\t #ad1jjj />s 7 obs]v$ at ,cambridge1 & we are deal+ ) t5 times t numb]47 ,! comp>ison %[s t ! ,cambridge obs]vations are affect$ ) ! foll[+ sy/ematic errors3-- ,if />s ( magnitude #aj are obs]v$ correctly1 !n #i #j4aj secs4 too e>ly #h #j4af #g #j4ai #f #j4ba #e #j4bc ,sid5ote3 ,ma9 object ( ! "w4 ,?is may s]ve z an illu/ration ( v>i\s incid5tal results :i* are already fl[+ f ! enorm\s & labori\s piece ( "w :i*1 z f> z ! ,univ]sity ,obs]vatory at ,ox=d is conc]n$1 we h j complet$1 ?\gh "s ( ! o!r colleagues are n s f> advanc$4 ,b ! ma9 results w n appe> j yet4 ,! "w mu/ be repeat$1 & ! positions ( ! />s j obta9$ mu/ be comp>$ ) ^? :i* !y w be f\nd to occupy at "s future date1 9 ord] to see :at k9d ( *anges are go+ on 9 ! heav5s4 ,:e!r ?is future date %all be "o hundr$ ye>s h5ce1 or fifty1 or t51 or :e!r we %\ld beg9 imm$iately to repeat :at has be5 done1 is a matt] n yet decid$1 & "o :i* requires "s little consid]ation4 ,sid5ote3 ,! conclud+ ye>4 ,i h said p]haps en\gh to give y a g5]al idea ( ! "w on :i* we h be5 engag$ at ,ox=d = ! la/ t5 ye>s4 ,t5 ye>s ago x seem$ to /ret* out 9 front ( u r hopelessly2 ! pace we 7 able to make seem$ s sl[ 9 view ( ! di/ance to be cov]$4 ,we felt r l ! s*oolboy :o has j return$ to s*ool & sees ! next holidays z a v remote prospect1 & we solac$ ourselves mu* 9 ! same way z he does1 by mak+ a diagram repres5t+ ! total numb] ( plates to be dealt ) & cross+ (f ea* "o z x 0 f9i%$1 j z he sometimes crosses (f ! days /ill rema9+ betwe5 him & ! prospective holidays4 ,x 0 pleasant to wat* ! gr[? ( ! numb] ( crosses on ?is diagram1 & by ! end ( ! ye> #aijb we _h ! satisfaction ( see+ v little blank space rema9+4 ,n[1 up to ?is po9t x _h n mu* matt]$ :e!r any p>ticul> plate 0 secur$ 9 any p>ticul> ye>1 or 9 a subsequ5t ye>1 s long z !re 7 always suffici5t plates to keep u occupi$ 9 measur+ !m4 ,b x !n became a matt] ( importance to secure ea* plate at ! prop] "t ( ye>2 = ! sun1 z we "k1 travels r\nd ! ,zodiac among ! />s1 oblit]at+ by 8 radiance a l>ge section ( ! sky = a p]iod ( "s mon?s1 & 9 ?is way a p>ticul> region ( ! heav5s is apt to run into daylight1 z ! obs]vatory phrase goes1 & ceases to be available = photography dur+ sev]al mon?s1 until ! sun is aga9 f> en\gh away to all[ ( ! p>ticul> region be+ se5 at night4 ,sid5ote3 ,a disappo9tm5t4 ,sid5ote3 ,a curi\s plate4 ,sid5ote3 ,a /range object4 ,sid5ote3 ,a new />8 ,r\ghly speak+ !n1 if a plate :i* %\ld be tak5 9 ,febru>y is n secur$ 9 ?is mon? ow+ to bad wea!r1 ! prop] "t = tak+ x w n occur aga9 until ! foll[+ ,febru>y2 & :5 !re 0 a fair prospect ( f9i%+ our "w 9 #aijc1 x became important to secure ea* plate at ! prop] "t 9 t ye>4 ,h5ce we 7 mak+ special ef=ts to utilise to ! full any f9e night t ,provid5ce s5t 9 our way1 & on su* occasions x is cle>ly an economy1 if n exactly to make hay :ile ! sun %9es1 at any rate to take plates vigor\sly :ile ! sun is n %9+ & ! night is f9e2 leav+ ! developm5t ( !m until ! daytime4 ,!re is1 ( c\rse1 ! risk t ! :ole night's "w may 9 ?is way be lo/ ow+ to "s fault 9 ! plates1 :i* might h be5 detect$ if "s ( !m 7 imm$iately develop$4 ,p]haps 9 ! e>ly days ( our "w x w\ld h be5 reckless or fooli% to neglect ?is little precaution2 b we _h = ye>s be5 accu/om$ to rely ^u ! excell5ce ( ! plates )\t f9d+ our tru/ betray$2 & ! s5sitiv5ess ( ! plates _h increas$ r ?an dim9i%$ z "t w5t on4 ,h5ce x w be readily und]/ood t :5 "o fatal morn+ we develop$ a s]ies ( "s ?irty plates1 & f\nd t ow+ to "s unexpla9$ lack ( s5sitiv5ess !y 7 all unsuitable = our purpose1 x came z a mo/ unwelcome & />tl+ surprise4 ,x 01 ( c\rse1 necess>y to make c]ta9 t !re 0 no ov]sight1 t ! develop] 0 n at fault1 & t ! wea!r _h n be5 trea*]\s4 ,all su* possibilities 7 c>efully consid]$ be=e communication ) ! mak]s ( ! plates1 b x ultimately became cle> t !re _h be5 "s un=tunate failure 9 s5sitiv5ess1 & t x w\ld be necess>y to repeat ! "w ) opportunities re/rict$ by ! int]v5+ lapse ( "t4 ,h[ev]1 disappo9tm5ts f ?is or simil> causes are n unkn[n 9 a/ronomical "w2 & we set ab\t ?is repetition ) z little loss ( "t & *e]fulness z 0 possible4 ,"u ! circum/ances1 h[ev]1 x seem$ desirable to exam9e c>efully :e!r any?+ c\ld be sav$ f ! wreck--:e!r any ( ! plates c\ld be admitt$ z j com+ up to ! m9imum requirem5ts4 ,& ,i devot$ a morn+ to ?is inquiry4 ,9 ! c\rse ( x ,i came across "o plate :i* c]ta9ly seem$ wor? an inclusion among our s]ies f ! po9t ( view ( ! numb] ( />s %[n ^u x4 ,x seem$ q ri* 9 />s1 p]haps ev5 a little ri*] ?an might h be5 expect$4 ,on inquiry ,i 0 told t ?is 0 n "o ( ! orig9ally condemn$ plates1 b "o :i* _h be5 tak5 s9ce ! failure 9 s5sitiv5ess ( ! plates _h be5 detect$2 0 f a new & specially s5sitive bat* ) :i* ! c\rte\s mak]s _h suppli$ u2 b ?\gh !re 7 c]ta9ly a suffici5t numb] ( />s ^u ! plate1 ow+ to "s unexpla9$ cause ! telescope _h be5 errone\sly po9t$1 & ! region tak5 did n correspond to ! region requir$4 ,to inve/igate ! cause ( ! discrepancy ,i !reupon took d[n f our /ore ( plates ! o!r "o ( ! same region :i* _h be5 reject$ = insuffici5cy ( />s1 & on comp>+ ! two x 0 at once evid5t t !re 0 a /range object on ! plate tak5 lat] ( ! two1 a bright /> or o!r heav5ly body1 :i* 0 n on ! =m] plate4 ,i h expla9$ t by repeat+ ! exposure m ?an once1 x is easily possible to recognise :e!r a m>k ^u ! plate is really a cele/ial body or is an accid5tal blot or du/ speck1 & !re 0 no d\bt t ?is 0 ! image ( "s /range cele/ial body4 ,x might1 ( c\rse1 be a new planet1 or ev5 an old "o :i* _h w&]$ into ! region2 b a few measures soon %[$ t x 0 n 9 movem5t4 ,! measures consi/$ 9 comp>+ ! sep>ation ( ! ?ree exposures ) ! sep>ation ( ! correspond+ exposures ( obvi\s />s1 = ! exposures 7 n1 ( c\rse1 simultane\s1 & if ! body 7 a planet & _h mov$ 9 ! int]val betwe5 !m1 ?is w\ld be made manife/ on measur+ ! sep>ations4 ,no su* movem5ts c\ld be detect$2 & ! possibilities 7 ?us re/rict$ to two4 ,s f> z we knew ! object 0 a />1 b might be ei!r a /> ( ! class kn[n z v>iable or ( t kn[n z new4 ,9 ! =m] case x w\ld become bright & fa9t at m or less regul> int]vals1 & might possibly h be5 already catalogu$2 = ! numb] ( ^! bodies already kn[n am\nts to "s hundr$s4 ,se>* be+ made 9 ! catalogues1 no entry ( x 0 f\nd1 ?\gh x /ill might be "o ( ?is class :i* _h hi!rto escap$ detection4 ,or x might be a new />1 "o ( ^? curi\s bodies :i* blaze up q sudd5ly to brightness & !n die away gradually until !y become practically invisible4 ,! mo/ fam\s p]haps ( ^! is ! /> :i* appe>$ 9 #aegb1 & 0 s c>efully obs]v$ by ,ty*o ,brahe2 b su* app>itions are r>e1 & altoge!r we h n records z yet ( a score altoge!r2 s t 9 ?is latt] case ! discov]y w\ld be ( mu* great] int]e/ ?an 9 ! =m]4 ,9 ei!r ev5t x 0 desirable to in=m o!r obs]v]s z soon z possible ( ! exi/5ce ( a /range body2 already "s "t _h elaps$ s9ce ! plate _h be5 tak51 ,m>* #af?1 = ! exam9ation ( :i* ,i h spok5 0 n made until ,m>* #bd?4 ,accord+ly1 a telegram 0 at once despat*$ to ! ,c5tral ,(fice at ,kiel1 :i* und]takes to di/ribute su* in=mation all ov] ! _w1 & a few po/-c>ds 7 s5t to obs]v]s close at h& :o might be able to obs]ve ! /> ! same night4 ,c]ta9 obs]vations ) ! spectroscope soon made x cle> t ! object 0 really a new />4 ,sid5ote3 ,! discov]y accid5tal4 ,sid5ote3 ,mrs4 ,flem+'s discov]ies4 ,?is1 !re=e1 is ! discov]y :i* we made at ,ox=d3 z y w see1 9 an entirely accid5tal mann]1 dur+ ! c\rse ( a piece ( "w 9 :i* x 0 c]ta9ly nev] contemplat$4 ,its purely accid5tal nature is suffici5tly illu/rat$ by ! fact t if ! plates orig9ally suppli$ by ! mak]s _h be5 ( ! prop] quality1 ! plate :i* l$ to ! discov]y w\ld nev] h be5 tak54 ,if ! plates expos$ 9 ,febru>y _h be5 satisfactory1 we %\ld h be5 cont5t1 & %\ld n h repeat$ ! exposure on ,m>* #af?4 ,aga9 ,i c te/ify p]sonally h[ purely accid5tal x 0 t ! exam9ation 0 made on ,m>* #bd? to see :e!r any?+ c\ld be sav$1 z ,i h said1 f ! wreck4 ,! idea came casually into my m9d z ,i 0 walk+ ?r\gh ! room & saw ! neat pile ( reject$ plates2 & "o may fairly call x an accid5tal impulse4 ,?is new /> is n1 h[ev]1 ! fir/ ( su* objects to h be5 discov]$ accid5tally2 _m ( ! o!rs 7 f\nd j z mu* by *ance1 ?\gh a notable exception mu/ be made ( ^? discov]$ at ! ,h>v>d ,obs]vatory1 :i* are ! result ( a delib]ate se>* = su* bodies by ! c>eful exam9ation ( photographic plates4 ,mrs4 ,flem+1 :o sp5ds h] life 9 su* "w1 has _h ! good =tune to detect no less ?an six ( ^! wond]ful objects z ! rew>d ( h] labori\s scrut9y2 & %e is ! only p]son :o has ?us f\nd new />s by photography until ?is accid5tal discov]y at ,ox=d4 ,! foll[+ is a complete li/ ( new />s discov]$ to date3-- ,,li/ ,,( ,,new ,,/>s4 ---------------------------------------- ------ ,ref4 ,no4 ,con/ellation4 ,ye>4 ,discov]]4 ---------------------------------------- ------ #a ,cassiopeia #aegb ,ty*o ,brahe4 #b ,cygnus #afjj ,janson4 #c ,ophiu*us #afjd ,kepl]4 #d ,vulpecula #afgj ,an!lm4 #e ,ophiu*us #ahdh ,h9d4 #f ,scorpio #ahfj ,auw]s4 #g ,corona ,borealis #ahff ,birm+ham4 #h ,cygnus #ahgf ,s*midt4 #i ,&rom$a #ahhe ,h>twig4 #aj ,p]seus #ahhg ,flem+4 #aa ,auriga #ahia ,&]son4 #ab ,norma #ahic ,flem+4 #ac ,c>9a #ahie ,flem+4 #ad ,c5taurus #ahie ,flem+4 #ae ,sagitt>ius #ahih ,flem+4 #af ,aquila #ahii ,flem+4 #ag ,p]seus #aija ,&]son4 #ah ,gem9i #aijc ,at ,ox=d4 ---------------------------------------- ------ ,illu/ration3 ,,m>* #a1 #aijc ,,m>* #ad1 #aijc ,,viii4--,,! ,,ox=d ,,new ,,/>4 ,a ,,pair ,,( ,,photographs ,,tak5 ,,at ,,! ,,h>v>d ,,college ,,obs]vatory ,,be=e ,,& ,,aft] ,,its ,,appe>ance 7,! arr[ indicates ! place ( ! new />4 ,x w be se5 t ! left-h& picture ?\gh x %ews fa9t] />s ?an ! o!r1 has n a trace ( ! new />47 ,sid5ote3 ,dr4 ,&]son4 ,sid5ote3 ,nova ,p]sei4 ,g5]ally ^! />s h be5 not$ by eye obs]vation1 z 9 ! case ( ! two f\nd by ,dr4 ,&]son ( ,ed9burgh4 ,9 ^! cases also we may say t delib]ate se>* 0 rew>d$2 = ,dr4 ,&]son is probably ! mo/ assidu\s wat*] ( ! skies liv+1 ?\gh he seldom uses a telescope2 sometimes he uses an op]a-glass1 b usually ! nak$ eye4 ,he describes himself z an ,a/rophil r ?an z an a/ronom]4 ,i love ! />s1 he says2 & :5ev] !y are %9+1 ,i mu/ be look+4 ,& s on e f9e night he /&s or sits at 8 op5 /udy w9d[ gaz+ at ! heav5s4 ,i believe he 0 j ab\t to leave !m = 8 b$1 ne> #c ,a4,m4 on ! night ( ,febru>y #ba1 #aija1 :51 ?r[+ a la/ glance upw>d1 he sudd5ly saw a brilliant /> 9 ! con/ellation ,p]seus4 ,8 fir/ feel+ 0 actually "o ( disappo9tm5t1 = he felt sure t ?is object mu/ h be5 !re = "s "t pa/ )\t 8 kn[+ ( x1 & he grudg$ ! "t lo/ :5 he might h be5 reg>d+ x4 ,m 9 a _s ( compla9t ?an ( inquiry1 he made 8 way to ! ,royal ,obs]vatory at ,ed9burgh next day to he> :at !y _h to say ab\t x1 ?\gh he f\nd x difficult to approa* ! subject4 ,he fir/ talk$ ab\t ! wea!r1 & ! crops1 & simil> topics ( g5]al int]e/2 & only aft] "s "t d>$ he v5ture a casual ref]5ce to ! new port5t 9 ! heav5s4 ,see+ 8 int]locutor look some:at blank1 he v5tur$ a little f>!r1 & made a direct ref]5ce to ! new /> 9 ,p]seus2 & !n f\nd to 8 a/oni%m5t1 z also to 8 great delight1 t he 0 ! fir/ to br+ news ( x4 ,! news 0 soon communicat$ to o!r obs]v]s2 all ! telescopes ( ! _w 7 soon tra9$ ^u x2 & ?is wond]ful new /> ( ! new c5tury has taught u m ( ! nature ( ^! extraord9>y bodies ?an all we knew be=e4 ,sid5ote3 ,records previ\s to discov]y4 ,sid5ote3 ,0 ,nova ,gem9orum previ\sly %9+ fa9tly8 ,sid5ote3 ,! suspicion negativ$4 ,p]haps ,i may add a few rem>ks on "o or two features ( ^! bodies4 ,fir/ly1 let u note t ,pr(essor ,pick]+ ( ,h>v>d is n[ able to make a mo/ important contribution to ! =m] hi/ory ( ^! objects--t is to say1 _! hi/ory prec$+ _! actual detection4 ,we rememb] t1 aft] ,uranus _h be5 discov]$1 x 0 f\nd t sev]al obs]v]s _h long be=e record$ its place unkn[+ly2 & simil>ly ,pr(essor ,pick]+ & 8 /aff h usually photograph$ o!r new objects unkn[+ly4 ,!re are on ! %elves at ,h>v>d va/ /ores ( photographs1 s _m t !y are unable to exam9e !m :5 !y h be5 tak52 b once any object ( int]e/ has be5 discov]$1 x is easy to turn ov] ! /ore & exam9e ! p>ticul> plates :i* may possibly %[ x at an e>li] date4 ,9 ?is way x 0 f\nd t ,dr4 ,&]son's new /> _h be5 visible only = a few days be=e its discov]y1 !re be+ no trace ( x on e>li] plates4 ,simil>ly1 9 ! case ( ! new /> f\nd at ,ox=d1 plates tak5 on ,m>* #a/ & #f?1 fifte5 days & t5 days respectively be=e ! discov]y-plate ( ,m>* #af?1 %[$ ! />4 ,b1 9 ?is p>ticul> in/ance1 great] int]e/ atta*es to two /ill e>li] plates tak5 else:]e1 & ) exposures mu* long] ?an any available at ,h>v>d4 ,"o _h be5 obta9$ at ,heidelb]g by ,dr4 ,max ,wolf1 & ano!r at ! ,y]kes ,obs]vatory ( ,*icago ,univ]sity1 by ,mr4 ,p>khur/2 & on bo? !re appe>$ to be a fa9t /> ( ab\t ! f\rte5? or fifte5? magnitude1 9 ! place subsequ5tly occupi$ by ! ,nova2 & ! "q naturally arose1 ,0 ?is ! object :i* ultimately blaz$ up & became ! new />8 ,to settle ?is po9t1 x 0 necess>y to measure its position1 ) ref]5ce to neighb\r+ />s1 ) extreme precision2 & "h x 0 un=tunate t ! photographs did n help u z mu* z !y might1 = !y 7 sc>cely capable ( be+ measur$ ) ! requisite precision4 ,! po9t 0 an important "o1 because if ! id5tity ( ! ,nova ) ?is fa9t /> c\ld be e/abli%$1 x w\ld be ! second in/ance ( ! k9d2 b s f> z !y w5t1 measurem5ts ( ! photographs 7 di/9ctly aga9/ ! id5tity4 ,su* 0 ! conclusion ( ,mr4 ,p>khur/ f 8 photograph alone2 & x 0 confirm$ by measures made at ,ox=d on copies ( bo? plates1 :i* 7 k9dly s5t !re = ! purpose4 ,! conclusion seem$ to be t !re 0 a fa9t /> v ne>1 b n at1 ! place ( ! new />2 & x 0 !re=e probable t1 al?\gh ?is fa9t /> 0 tempor>ily invisible f ! brightness ( ! adjac5t ,nova1 z ! latt] became fa9t] 79 ! way ) :i* we h become famili> 9 ! case ( new />s71 x might be possible to see ! two />s alongside ea* o!r4 ,?is critical obs]vation 0 ultimately made by ! %>p eyes ( ,pr(essor ,b>n>d1 aid$ by ! giant telescope ( ! ,y]kes ,obs]vatory2 & x seems cle> !re=e t ! object :i* blaz$ up to become ! ,nova ( #aijc c\ld n h previ\sly be5 s bright z a fa9t /> ( ! f\rte5? magnitude4 ,al?\gh ?is is m]ely a negative conclusion1 x is an important "o 9 ! hi/ory ( ^! bodies4 ,sid5ote3 ,nebula r\nd ,nova ,p]sei4 ,sid5ote3 ,its *anges4 ,sid5ote3 ,due to travell+ illum9ation4 ,! second po9t to :i* ,i w draw y\r att5tion is f ! hi/ory ( ! o!r ,nova j m5tion$--,dr4 ,&]son's ,new ,/> ( #aija4 ,9 ?is in/ance x is n ! hi/ory previ\s to discov]y1 b :at foll[$ _m mon?s aft] discov]y1 t 0 ( engross+ int]e/2 & aga9 ,y]kes ,obs]vatory1 ) its magnific5t equipm5t1 play$ an important "p 9 ! drama4 ,:51 ) its giant reflect+ telescope1 photographs 7 tak5 ( ! region ( ,nova ,p]sei aft] x _h become comp>atively fa9t1 x 0 f\nd t !re 0 an extraord9>ily fa9t nebulosity surr\nd+ ! />4 ,repeat+ ! photographs at int]vals1 x 0 f\nd t ?is nebulosity 0 rapidly *ang+ 9 %ape4 ,rapidly is1 ( c\rse1 a relative t]m1 & a casual inspection ( two ( ! photographs might n convey any impression ( rapidity2 x is only :5 we come to consid] ! enorm\s di/ance at :i* ! movem5ts1 or app>5t movem5ts1 ( ! nebulae mu/ be tak+ place t x becomes cle> h[ rapid ! *anges mu/ be4 ,x 0 n possible to det]m9e ?is di/ance ) any exactness1 b limits to x c\ld be set1 & x seem$ probable t ! velocity ( ! movem5t 0 comp>able ) t ( light4 ,! conclusion sugge/$ itself t ! velocity might actually be id5tical ) t ( light1 9 :i* case :at we saw 0 n ! movem5t ( actual matt]1 b m]ely t ( illum9ation1 travell+ f po9t to po9t ( matt] already exi/+4 ,illu/ration3 ,,sept4 #bj1 #aija ,,nov4 #ac1 #aija ,,ix--,,nebulosity ,,r\nd ,,nova ,,p]sei 7,f photographs tak5 at ! ,y]kes ,obs]vatory by ,g4 ,w4 ,rit*ey47 ,sid5ote3 ,:5 did x all happ58 ,an analogy f ! famili> case ( s\nd may make cle>] :at is meant4 ,if a l\d noise is made 9 a l>ge hall1 we he> e*oes f ! walls4 ,! s\nd travels ) a velocity ( ab\t #aajj feet p] second1 rea*es ! walls1 is reflect$ back f !m1 & returns to u ) ! same velocity4 ,f ! int]val occupi$ 9 go+ & return+ we c\ld calculate ! di/ance ( ! walls4 ,! velocity ( light is s enorm\s comp>$ ) t ( s\nd t we are usually q unable to obs]ve any simil> ph5om5on 9 ! case ( light4 ,if we /rike a mat* 9 ! l>ge/ hall1 all p>ts ( x are illum9at$ s imm$iately t we _c possibly realise t !re 0 really an int]val betwe5 ! /rik+ ( ! mat*1 ! travell+ ( ! light to ! walls1 & its return to our eyes4 ,! scale ( our t]re/rial ph5om5on is f> too small to r5d] ?is int]val p]ceptible4 ,b ^? :o accept ! !ory above m5tion$ reg>d+ ! appe>ances r\nd ,nova ,p]sei 7al?\gh !re are "s :o discr$it x7 believe t we h 9 ?is case an illu/ration ( j ?is ph5om5on ( light e*oes1 on a scale l>ge en\gh to be easily visible4 ,!y ?9k t1 surr\nd+ ! c5tral /> :i* blaz$ up s brightly 9 ,febru>y #aija1 !re 0 a va/ d>k nebula1 ( :i* we _h no previ\s k1 because x 0 n %9+ ) any light ( its own4 ,:5 ! /> blaz$ up1 ! illum9ation travell$ f po9t to po9t ( ?is d>k nebula & light$ x up2 b ! size ( ! nebula 0 s va/ t1 al?\gh ! light 0 travell+ ) ! enorm\s velocity ( #bjj1jjj miles p] second1 x 0 n until mon?s aft]w>ds t x rea*$ diff]5t portions ( ?is nebula2 & we accord+ly got news ( ! exi/5ce ( ?is nebula "s mon?s aft] ! news rea*$ u ( ! c5tral conflagration1 :atev] x 04 ,rem>k t all we c say is t ! news ( ! nebula rea*$ u "s mon?s lat] ?an t ( ! outbur/4 ,! actual date :5 ei!r ( ! actual ?+s happ5$1 we h z yet no means ( kn[+2 x may h be5 hundr$s or ev5 ?\s&s ( ye>s ago t ! conflagration actually occurr$ ( :i* we got news 9 ,febru>y #aija1 ! light hav+ tak5 all t "t to rea* u f t di/ant "p ( space2 & ! light reflect$ f ! nebula 0 foll[+ x on its way to u all ^! ye>s at t same int]val ( a few mon?s4 ,sid5ote3 ,an objection4 ,n[1 let me ref] be=e leav+ ?is po9t to ! *ief objection :i* has be5 urg$ aga9/ ?is !ory4 ,x has be5 ma9ta9$ t ! illum9ation w\ld necess>ily appe> to travel outw>ds f ! c5tre ) an approa* to uni=mity1 :]eas ! obs]v$ rate ( travel is n uni=m1 & has be5 ev5 t[>ds ! c5tre in/ead ( away f x2 :i* w\ld seem z ?\gh portions ( ! nebula m di/ant f ! c5tre 7 light$ up soon] ?an ^? clos] to x4 ,by a simple illu/ration f our sol> sy/em1 we %all see t ^! curi\s anomalies may easily be expla9$4 ,let u consid] = simplicity two planets only1 say ! ,e>? & ,saturn4 ,we "k t ,saturn travels r\nd ! sun 9 an orbit :i* is t5 times l>g] ?an ! orbit ( ! e>?4 ,suppose n[ t ! sun 7 sudd5ly to be ext+ui%$2 light takes ab\t eight m9utes to travel f ! sun to ! e>?1 & consequ5tly we %\ld n get news ( ! ext9ction = "s eight m9utes2 ! sun w\ld appe> to u to /ill g on %9+ = eight m9utes aft] he _h really be5 ext+ui%$4 ,saturn be+ ab\t t5 times z f> away f ! sun1 ! news w\ld take eighty m9utes to rea* ,saturn2 & f ! e>? we %\ld see ,saturn %9+ m#c ?an eighty m9utes aft] ! sun _h be5 ext+ui%$1 al?\gh we ourselves %\ld h lo/ ! sun's light aft] eight m9utes4 ,i ?9k we already beg9 to see possibilities ( curi\s anomalies2 b !y c be made cle>] ?an ?is4 ,in/ead ( imag9+ an obs]v] on ! e>?1 let u suppose him remov$ to a great di/ance away 9 ! plane ( ! two orbits2 & let u suppose t ! sun is n[ light$ up aga9 z sudd5ly z ! new /> blaz$ up 9 ,febru>y #aija4 ,!n su* an obs]v] w\ld fir/ see ?is blaze 9 ! c5tre2 eight m9utes aft]w>ds ! illum9ation w\ld rea* ! e>?1 a little speck ( light ne> ! sun w\ld be illum9at$1 j z we saw a portion ( ! d>k nebula r\nd ,nova ,p]sei illum9at$2 eighty m9utes lat] ano!r speck1 namely1 ,saturn1 w\ld beg9 to %9e4 ,b n[1 w\ld ,saturn necess>ily appe> to ! di/ant obs]v] to be f>!r away f ! sun ?an ! e>? 08 ,look+ at ! diagram1 we c see t if ,saturn 7 at ,s#a !n x w\ld pres5t ?is natural appe>ance ( be+ f>!r away f ! sun ?an ! e>?2 b x might be at ,s#b or ,s#c1 9 :i* case x w\ld seem to be ne>] ! sun1 & ! illum9ation w\ld seem to travel inw>ds t[>ds ! c5tral body in/ead ( outw>ds4 ,)\t consid]+ o!r cases 9 detail1 x w be tol]ably cle> t almo/ any anomal\s appe>ance might be expla9$ by *oos+ a suitable arrangem5t ( ! nebul\s matt] :i* we suppose light$ up by ! explosion ( ,nova ,p]sei4 ,ano!r objection urg$ aga9/ ! !ory ,i h sket*$ is t ! light reflect$ f su* a nebula w\ld be s feeble t x w\ld n affect our photographic plates4 ,?is dep5ds ^u v>i\s assumptions :i* we h no "t to notice "h2 b ,i ?9k we may say t !re is c]ta9ly room = ! acceptance ( ! !ory4 ,illu/ration3 ,,fig4 #f4 ,sid5ote3 ,did ! nebula cause ! outbur/8 ,n[1 if ?is d>k nebula 0 previ\sly exi/+ 9 ?is way all r\nd ! /> :i* blaz$ up1 ! "q naturally arises :e!r ! nebula _h any?+ to d ) ! conflagration4 ,0 !re previ\sly a />1 ei!r s cold or s di/ant z n to be %9+ ) appreciable light1 :i*1 travell+ ?r\gh space1 enc\nt]$ ?is va/ nebula1 & by ! friction ( ! enc\nt] 0 sudd5ly r5d]$ s lum9\s z to out%9e a /> ( ! fir/ magnitude8 ,! case ( meteoric /ones /rik+ our own atmosph]e seems to sugge/ su* a possibility4 ,^! little /ones are previ\sly q cold & invisible1 & are travell+ 9 "s way ?r\gh space1 _m ( !m probably circl+ r\nd our sun4 ,if !y happ5 9 _! j\rney to enc\nt] our e>?1 ev5 ! extremely t5u\s atmosph]e1 s ?9 t x w sc>cely b5d ! rays ( light appreciably1 ev5 ?is is suffici5t by its friction to raise ! /ones to a :ite heat1 s t !y blaze up into ! fall+ />s ) :i* we are famili>4 ,?is analogy is sugge/$1 b we mu/ be cauti\s 9 accept+ x2 = we "k s v little ( ! nature ( nebulae su* z t ( :i* we h be5 speak+4 ,b 9 any case1 a totally new s]ies ( ph5om5a h be5 laid op5 to our /udy by ^? wond]ful photographs tak5 at ! ,y]kes ,obs]vatory & ! ,lick ,obs]vatory 9 ! few ye>s :i* ! pres5t c5tury has z yet run4 ,sid5ote3 ,importance ( new />s ,"o ?+ is q c]ta93 we mu/ lose no opportunity ( /udy+ su* />s z may appe>1 & no dilig5ce sp5t 9 discov]+ !m at ! e>lie/ possible mom5t is ?r[n away4 ,we h only kn[n up to ! pres5t1 z already /at$1 less ?an a score ( !m1 & ( ^! _m h told u b little2 p>tly because !y 7 only discov]$ too late 7aft] !y _h become fa9t71 & p>tly because ! e>li] ones c\ld n be obs]v$ ) ! spectroscope1 :i* _h n !n be5 inv5t$4 ,x seems cle> t 9 ! future we mu/ n all[ accid5t to play s l>ge a "p 9 ! discov]y ( ^! objects2 m mu/ be done 9 ! way ( delib]ate se>*4 ,al?\gh we "k be=eh& t ?is w involve a va/ am\nt ( app>5tly useless lab\r1 t mon?s & ye>s mu/ be sp5t 9 comp>+ photographic plates1 or portions ( ! sky itself1 ) "o ano!r )\t detect+ any?+ rem>kable1 x w n be ! fir/ "t t ye>s h be5 *e]fully sp5t 9 su* se>*es )\t result4 ,we ne$ only recall ,h5cke's fifte5 ye>s ( fruitless se>*1 be=e f9d+ a m9or planet1 to realise ?is fact4 ,sid5ote3 ,sup]position ( plates4 ,sid5ote3 ,! /]eo-comp>ator4 ,"o ?+ ( importance may be done2 we may improve our me?ods ( mak+ ! se>*1 s z to economise lab\r1 & sev]al successful attempts h already be5 made 9 ?is direction4 ,! simple/ plan is to sup]pose two photographs tak5 at diff]5t dates1 s t ! />s on "o lie v close to ^? on ! o!r2 !n if an image is se5 to be unpair$ we may h f\nd a new />1 ?\gh ( c\rse ! object may be m]ely a planet or a v>iable4 ,! sup]position ( ! plates may be ei!r actual or virtual4 ,a beautiful in/rum5t has be5 devis$ on ! pr9ciple ( ! /]eoscope = exam9+ two plates plac$ side by side1 "o ) ea* eye4 ,we "k t 9 ?is way two photographs ( ! same object f diff]5t po9ts ( view w appe> to coalesce1 & at ! same "t to give an appe>ance ( solidity to ! object or l&scape1 portions ( :i* w seem to /& out 9 front ( ! backgr\nd4 ,apply+ ?is pr9ciple to two photographs ( />s1 :at happ5s is ?is3 if ! />s h all rema9$ 9 ! same positions exactly1 ! two pictures w seem to u to coalesce1 & ! images all to lie on a flat backgr\nd2 b if 9 ! int]val betwe5 ! exposures ( ! two plates "o ( ! />s has appreciably mov$ or disappe>$1 x w seem1 :5 look$ at ) ?is in/rum5t1 to /& out 9 front ( ?is backgr\nd1 & is accord+ly detect$ ) comp>atively little tr\ble4 ,?is new in/rum5t1 to :i* ! "n ,/]eo-comp>ator has be5 giv51 promises to be ( imm5se value 9 dr$g+ ! sky = /range bodies 9 ! future4 ,i am glad to say t a g5]\s fri5d has k9dly pres5t$ ! ,univ]sity ,obs]vatory at ,ox=d ) "o ( ^! beautiful in/rum5ts1 :i* h be5 con/ruct$ by ,messrs4 ,zeiss ( ,j5a aft] ! skilful designs ( ,dr4 ,pulfri*4 ,:e!r we %all be able to repeat by delib]ate se>* ! success :i* m]e accid5t ?rew 9 our way rema9s to be se54 ,,*apt] ,v ,,s*wabe ,,& ,,! ,,sun-,,spot ,,p]iod ,sid5ote3 ,discov]ies contr>y to expectation4 ,9 prec$+ *apt]s we h review$ discov]ies1 "s ( :i* h be5 made z a result ( a delib]ate se>*1 & o!rs accid5tally 9 ! c\rse ( "w direct$ to a totally diff]5t end2 b s f> we h n consid]$ a case 9 :i* ! discov]] ent]$ ^u an ent]prise f :i* he 0 positively dissuad$4 ,sid5ote3 ,no?+ expect$ f spots4 ,9 ! next *apt] we %all come across a v /rik+ in/ance ( ?is type2 b ev5 9 ! discov]y t !re 0 a p]iodicity 9 ! sol> spots1 ) :i* ,i propose to deal n[1 ,h]r ,s*wabe began 8 "w 9 ! face ( det]r5t op9ions f em95t m54 ,8 def9ite ann\ncem5t 0 fir/ made 9 #ahdc1 ?\gh he _h himself be5 conv9c$ "s ye>s e>li]4 ,9 #aheg ! ,royal ,a/ronomical ,society aw>d$ him _! gold m$al = ! discov]y2 & 9 ! address deliv]$ on ! occasion ! ,presid5t comm5c$ by draw+ att5tion to ?is v fact1 t a/ronom]s :o _h express$ any op9ions on ! subject _h be5 uni=mly & decid$ly aga9/ ! likelihood ( !re be+ any?+ pr(itable 9 ! /udy ( ! sol> spots4 ,i w quote ! exact words ( ! ,presid5t1 ,mr4 ,manuel ,johnson1 !n ,radcliffe ,obs]v] at ,ox=d4 ,x 0 9 #ahbf t ,he9ri* ,s*wabe1 a g5tleman resid5t 9 ,dessau1 ent]$ ^u ^? rese>*es :i* are n[ to engage our att5tion4 ,i am n aw>e ( ! motive t induc$ him--:e!r any p>ticul> views _h sugge/$ !mselves to 8 own m9d--or :e!r x 0 a g5]al desire ( inve/igat+1 m ?or\ghly ?an 8 pr$ecessors _h done1 ! laws ( a rem>kable ph5om5on1 :i* x _h long be5 ! fa%ion to neglect4 ,he c\ld h>dly h anticipat$ ! k9d ( result at :i* he has arriv$2 at ! same "t we _c imag9e a c\rse ( proce$+ bett] calculat$ = its detection1 ev5 if 8 m9d _h be5 prep>$ = x1 ?an t :i* he has pursu$ f ! v comm5cem5t ( 8 c>e]4 ,assur$ly if he ent]ta9$ su* an idea1 x 0 n borr[$ f ! au?orities ( ! la/ c5tury1 to :om ! sol> spots 7 objects ( m att5tion ?an !y h be5 ( late ye>s4 ',nulla con/anti temporum lege app>5t aut evanescunt1' says ,keill 9 #agci4--;,introduct4 ad ,physic4 ,a/ronom41 p4 #bec4 ',il e/ manife/ p> ce que n\s v5ons de rapport] qu'il n'y a po9t de regle c]ta9e de leur =mation1 ni de leur nombre et de leur figure1' says ,cass9i ,,ii4 9 #agdj4--;,elem d',a/ron41 vol4 i4 p4 #hb4 ',il semble qu'elles ne suiv5t aucune loi dans leur app>itions1' says ,le ,monni] 9 #agdf4--;,in/it4 ,a/ron41 p4 #hc4 ',sol> spots obs]ve no regul>ity 9 _! %ape1 magnitude1 numb]1 or 9 ! "t ( _! appe>ance or cont9uance1' says ,long 9 #agfd4--;,a/ron41 vol4 ii4 p4 #dgb4 ',les app>itions des ta*es du soleil n'ont ri5 de reguli]1' says ,lal&e 9 #agga4--;,a/ron41 vol4 iii4 ,sec4 #caca1 #bnd edit4 ,& ,delambre's op9ion may be inf]r$ f a well-kn[n passage 9 ! ?ird volume ( 8 ',a/ronomy' 7p4 #bj71 publi%$ 9 #ahad1 :]e treat+ ( ! sol> spots he says1 ',il e/ vrai qu'elles sont plus curieuses que vraim5t utiles4'#d ,x w ?us be evid5t t ,h]r ,s*wabe _h ! c\rage to ent] ^u a l9e ( inve/igation :i* o!rs _h practically condemn$ z likely to lead n[h]e1 & t 8 discov]y 0 q contr>y to expectation4 ,x is a lesson to u t n ev5 ! mo/ unlikely l9e ( "w is to be despis$2 = ! outcome ( ,s*wabe's "w 0 ! fir/ /ep 9 ! :ole s]ies ( discov]ies :i* h gradually built up ! mod]n sci5ce ( ,sol> ,physics1 :i* occupies s des]v$ly l>ge a "p ( ! en]gies (1 = in/ance1 ! great obs]vatory atta*$ to ! ,univ]sity ( ,*icago4 ,sid5ote3 ,s*wabe's ann\ncem5t4 ,x has be5 our practice to recall ! actual words 9 :i* ! discov]] himself /at$ 8 discov]y1 & ,i w give ! orig9al mode/ ann\ncem5t ( ,s*wabe1 ?\gh = conv5i5ce ( ^? :o d n read ,g]man ,i w attempt a r\gh translation4 ,he _h communicat$ ye> by ye> ! results ( 8 daily c\nt+ ( ! sol> spots to ! ,a/ronomis*e ,na*ri*t51 & aft] he _h giv5 t5 ye>s' results 9 ?is way he collect$ !m toge!r1 b he made no rem>k on ! curi\s sequ5ce :i* !y und\bt$ly %[$ at t "t4 ,wait+ pati5tly six ye>s = fur!r mat]ial1 9 #ahdc he v5tur$ to make 8 def9ite ann\ncem5t z foll[s3--,f my e>li] obs]vations1 :i* ,i h communicat$ annually to ?is j\rnal1 !re 0 manife/ already a c]ta9 p]iodicity ( sun-spots2 & ! probability ( ?is be+ really ! case is confirm$ by ?is ye>'s results4 ,al?\gh ,i gave 9 volume #ae ! total numb]s ( gr\ps = ! ye>s #ahbf-ahcg1 nev]!less ,i w repeat "h a complete s]ies ( all my obs]vations ( sun-spots1 giv+ n only ! numb] ( gr\ps1 b also ! numb] ( days ( obs]vation1 & fur!r ! days :5 ! sun 0 free f spots4 ,! numb] ( gr\ps alone w n 9 itself give suffici5t accuracy = det]m9ation ( a p]iod1 s9ce ,i h conv9c$ myself t :5 !re are a l>ge numb] ( sun-spots ! numb] w be reckon$ some:at too small1 & :5 few sun-spots1 ! numb] some:at too l>ge2 9 ! fir/ case sev]al gr\ps are (t5 c\nt$ toge!r 9 "o1 & 9 ! second x is easy to divide a gr\p made up ( two compon5t p>ts into two sep>ate gr\ps4 ,?is mu/ be my excuse = repeat+ ! e>ly catalogue1 z foll[s3-- ---------------------------------------- ----- ,ye>4 ,numb] ( ,days free ,days ( ,gr\ps4 f ,spots4 ,obs]vation4 ---------------------------------------- ----- #ahbf #aah #bb #bgg #ahbg #afa #b #bgc #ahbh #bbe #j #bhb #ahbi #aii #j #bdd #ahcj #aij #a #bag ---------------------------------------- ----- #ahca #adi #c #bci #ahcb #hd #di #bgj #ahcc #cc #aci #bfg #ahcd #ea #abj #bgc #ahce #agc #ah #bdd ---------------------------------------- ----- #ahcf #bgb #j #bjj #ahcg #ccc #j #afh #ahch #bhb #j #bjb #ahci #afb #j #bje #ahdj #aeb #c #bfc ---------------------------------------- ----- #ahda #ajb #ae #bhc #ahdb #fh #fd #cjg #ahdc #cd #adi #cbd 7#ahdd7 7#eb7 7#aaa7 7#cbj7 ---------------------------------------- ----- ,if we n[ comp>e toge!r ! numb] ( gr\ps1 & ! days free f spots1 we f9d t ! sun-spots h a p]iod ( ab\t t5 ye>s1 & t = ab\t five ye>s !y are s num]\s t dur+ ?is p]iod few days1 if any1 are free f spots4 ,! sequel mu/ %[ :e!r ?is p]iod is con/ant1 :e!r ! m9imum activity ( ! sun 9 produc+ spots la/s = "o or two ye>s1 & :e!r ?is activity increases m quickly ?an x decreases4 ,illu/ration3 ,,feb4 #ah1 #ahid4 ,,feb4 #ai1 #ahid4 ,x4--,,photographs ,,( ,,! ,,sun ,,tak5 ,,at ,,! ,,royal ,,obs]vatory1 ,,gre5wi*1 ,,%ew+ ,,sunspots4 ,sid5ote3 ,attract$ little att5tion1 until eight ye>s lat]4 ,?is brief ann\ncem5t is all t ! discov]] says ^u ! subject2 & x is p]haps n rem>kable t x attract$ v little att5tion1 especially :5 we rememb] t x relat$ to a matt] :i* ! a/ronomical _w _h agre$ to put aside z unpr(itable & n wor? att5tion4 ,next ye>1 9 giv+ 8 usual pap] on ! spots = #ahdd he recurs to ! subject 9 ! foll[+ s5t5ce3 ,! p]iodicity ( spots ( ab\t t5 ye>s :i* 0 indicat$ 9 my summ>y publi%$ la/ ye>1 is confirm$ by ?is ye>'s obs]vations4 ,i h add$ 9 brackets to ! table above reproduc$ ! numb]s = #ahdd subsequ5tly giv51 & x w be se5 h[ ne>ly !y might h be5 pr$ict$4 ,sid5ote3 ,o!r ph5om5a sympa!tic & o!rs n4 ,/ill ! subject attract$ little att5tion4 ,turn+ ov] ! leaves ( ! j\rnal at r&om1 ,i came across ! annual report ( ! ,a/ronom] ,royal ( ,engl&1 pr9t$ at l5g?4 ,b 9 x !re is no ref]5ce to ?is discov]y1 :i* op5$ up a l9e ( "w n[ /rongly repres5t$ 9 ! annual programme ( ! ,royal ,obs]vatory at ,gre5wi*4 ,mr4 ,johnson rem>ks t ! only p]son :o _h tak5 x up 0 ,julius ,s*midt1 :o !n resid$ ne> ,hamburg4 ,b ,s*wabe w5t on pati5tly accumulat+ facts2 & 9 #ahea ! great ,von ,humboldt 9 ! ?ird volume ( 8 ,cosmos1 drew att5tion to ! discov]y1 :i* 0 accord+ly = ! fir/ "t br\ght into g5]al notice4 ,x w be se5 t !re are n _m facts ( g5]al int]e/ relat+ to ! actual discov]y beyond ! c\rage ) :i* ! "w 0 comm5c$ 9 a totally unpromis+ direction1 & ! scant att5tion x receiv$ aft] be+ made = u4 ,we may admit t int]e/ c5tres *iefly 9 ! trem5d\s consequ5ces :i* fl[$ f x4 ,we n[ recognise t _m o!r ph5om5a are b\nd up ) ?is wax+ & wan+ ( ! sol> spots4 ,we might be prep>$ = a sympa?y 9 ph5om5a obvi\sly connect$ ) ! sun itself2 b x 0 an unexpect$ & />tl+ discov]y t magnetic ph5om5a on ! e>? _h also a sympa!tic relation ) ! *anges 9 sun-spots1 & x is p]haps n surpris+ t :5 once ?is connection ( sol> & t]re/rial ph5om5a 0 realis$1 v>i\s attempts h be5 made to ext5d x into regions :]e we _c z yet all[ t x has e>n$ a legitimate "r ( entry4 ,we h he>d ( ! wea!r & ( ,indian fam9es occurr+ 9 cycles id5tical ) ! sun-spot cycle2 & x is obvi\s h[ trem5d\sly important x w\ld be = u if ?is 7 f\nd to be actually ! case4 ,= we might 9 ?is way pr$ict ye>s ( possible fam9e & gu>d aga9/ !m2 or if we c\ld ev5 p>tially =etell ! k9d ( wea!r likely to occur "s ye>s h5ce1 we might take agricultural measures accord+ly4 ,! importance ( ! connection1 if only x c\ld be e/abli%$1 is no d\bt ! reason :i* has misl$ inve/igators into lay+ undue /ress on evid5ce :i* w n be> close scrut9y4 ,= ! pres5t we mu/ say decid$ly t no case has be5 made out = pay+ s]i\s att5tion to ! influ5ce ( sun-spots on wea!r4 ,nev]!less1 putt+ all ?is aside1 !re is q en\gh ( fir/-rate importance 9 ! sequel to ,s*wabe's discov]y4 ,sid5ote3 ,gre5wi* sun records4 ,sid5ote3 ,! sun's rotation4 ,let u review ! facts 9 ord]4 ,mo/ ( u1 ?\gh we may n h _h ! advantage ( see+ an actual sun-spot ?r\gh a telescope1 h se5 draw+s or photographs ( spots4 ,!re is a fam\s draw+ made by ,james ,nasmy? 7( /eam-hamm] fame71 9 ,july1 #ahfd1 :i* is ( p>ticul> int]e/1 because at t "t ,nasmy? 0 conv9c$--& he conv9c$ _m o!rs ) him--t ! sol> surface 0 made up ( a miscellane\s heap ( solid bodies 9 %ape l will[ leaves1 or gra9s ( rice1 ?r[n toge!r almo/ at r&om1 & ! draw+ 0 made by him to illu/rate ?is idea4 ,comp>+ a mod]n photograph ) x1 we see t !re is some?+ to be said = ,nasmy?'s view1 :i* attract$ mu* att5tion at ! "t & occasion$ a some:at heat$ controv]sy4 ,b s9ce ! inv5tion ( ! spectroscope x has become q obsolete2 x probably does n correspond 9 any way to ! real facts4 ,b in/ead ( look+ at pictures :i* h be5 enl>g$ to %[ ! detail$ /ructure 9 & ne> a spot1 we w look at a s]ies ( pictures ( ! :ole sun tak5 on successive days at ,gre5wi* 9 :i* ! spots are necess>ily mu* small]1 b :i* %[ ! behavi\r ( ! spots f day to day4 7,see ,plates ,x4 & ,,xi47 ,f ! date at ! foot ( ea* x w be se5 t !y gradually cross ! disc ( ! sun 7a fact fir/ discov]$ by ,galileo 9 #afaj71 %[+ t ! sun rotates on an axis once 9 ab\t e tw5ty-five days4 ,!re are _m int]e/+ facts connect$ ) ?is rotation2 especially t ! sun does n rotate z a solid body1 ! p>ts ne> ! 7,sun's7 ,equator fl[+ quick] ?an ^? ne>] ! ,poles2 b = ! pres5t we _c /op to dwell ^u !m4 ,:at int]e/s u p>ticul>ly is ! hi/ory1 n f day to day1 b f ye> to ye>1 z ,s*wabe has already giv5 x = a s]ies ( ye>s4 ,illu/ration3 ,,feb4 #bj1 #ahid4 ,,feb4 #ba1 #ahid4 ,,xi4--,,photographs ,,( ,,! ,,sun ,,tak5 ,,at ,,! ,,royal ,,obs]vatory1 ,,gre5wi*1 ,,%ew+ ,,sunspots ,sid5ote3 ,wolf's numb]s4 ,sid5ote3 ,gre5wi* areas4 ,sid5ote3 ,magnetic fluctuations4 ,:5 x became g5]ally e/abli%$ t ?is p]iodicity exi/$1 ,rudolf ,wolf ( ,zuri* collect$ ! facts ab\t sun-spots f ! e>lie/ possible date1 & repres5t$ ?is hi/ory by a s]ies ( numb]s :i* are /ill call$ ,wolf's ,sun-,spot ,numb]s4 ,y w see f ! diagram ! obvi\s rise & fall = elev5 ye>s1--n t5 ye>s1 z ,s*wabe ?\ght1 b j a little ov] elev5 ye>s4 ,! facts are1 h[ev]1 giv5 m completely by ! "w done at ! ,royal ,obs]vatory at ,gre5wi*4 ,x is "p ( ! regul> daily "w ( t ,obs]vatory to photograph ! sun at lea/ twice4 ,_m days are ( c\rse cl\dy or wet1 s t photographs _c be obta9$2 b !re are available photographs simil>ly tak5 9 ,india or 9 ,mauritius1 :]e ! wea!r is m fav\rable1 & f ^! ! gaps are s well fill$ up t v few days1 if any1 dur+ ! :ole ye> are left )\t "s photograph ( ! sun's surface4 ,on ^! photographs ! positions & ! areas ( ! spots are c>efully measur$ "u a microscope1 & ! results :5 submitt$ to c]ta9 necess>y calculations are publi%$ ye> by ye>4 ,x is cle>ly a m accurate e/imate ( ! spott$ness ( ! sun to take ! total area ( all ! spots r ?an _! m]e numb]1 = 9 ! latt] case a l>ge spot & a small "o c\nt equally4 ,h5ce ! ,gre5wi* records w p]haps give u an ev5 bett] idea ( ! p]iodicity ?an ,wolf's numb]s4 ,n[1 at ! same obs]vatory magnetic obs]vations are also made cont9u\sly4 ,if a magnet be susp5d$ freely we are accu/om$ to say t x w po9t to ! ,nor? ,pole2 b ?is is only v r\ghly true4 ,9 ! fir/ place1 x is probably well kn[n to y t !re is a consid]able deviation f due nor? ow+ to ! fact t ! magnetic ,nor? ,pole is n ! same z ! geographical ,nor? ,pole2 b ?is = ! pres5t ne$ n conc]n u4 ,:at does conc]n u is1 t if ! ne$le is hung up & left long en\gh to come to re/1 x does n !n rema9 /eadily at re/1 b executes sl[ & small oscillations backw>ds & =w>ds1 up & d[n1 ?r\gh\t ! day2 repeat+ ne>ly ! same oscillations on ! foll[+ day1 b at ! same "t gradually *ang+ its behavi\r s z to oscillate diff]5tly 9 summ] & w9t]4 ,^! *anges are v small1 & w\ld pass unnotic$ by ! nak$ eye2 b :5 c>efully wat*$ ?r\gh a telescope1 or bett] /ill1 :5 photograph$ by "s app>atus :i* w at ! same "t magnify !m1 !y c be r5d]$ easily visible4 ,:5 ! hi/ory ( ^! *anges is trac$ x is se5 at once t !re is a manife/ connection ) ! cycle ( sun-spot *anges2 = in/ance1 if we measure ! range ( sw+ backw>ds & =w>ds dur+ ! day & take ! av]age = all ! days 9 ! ye>1 & !n comp>e ?is ) ! av]age numb] ( sun-spots1 we %all see t ! av]ages rise & fall toge!r4 ,simil>ly we may take ! up & d[n sw+1 f9d ! av]age am\nt ( x ?r\gh\t ! ye>1 & aga9 we %all f9d t ?is corresponds v closely ) ! av]age numb] ( sun-spots4 ,illu/ration3 ,,plate ,,xii4 ,,numb] ,,( ,,sunspots 7,wolf7 ,comp>$ ) ,,daily ,,range ( ,,magnetic ,,decl9ation ,,daily ,,range ( ,,magnetic ,,horzl4 ,,=ce 7z obs]v$ at ,gre5wi*47 ,sid5ote3 ,daily curves4 ,sid5ote3 ,diff]5ce betwe5 summ] & w9t]1 & betwe5 sun-spot maximum & m9imum4 ,sid5ote3 ,cause unkn[n4 ,b p]haps ! mo/ /rik+ way to exhibit ! sympa?y is to comb9e diff]5t v>iations ( ! ne$le into "o picture4 ,& fir/ we mu/ rem>k t !re is ano!r important v>iation ( ! e>?'s magnetic action :i* we h n yet consid]$4 ,we h m5tion$ ! sw+ ( ! ne$le to & fro1 & ! sw+ up & d[n1 & ^! correspond to *anges 9 ! direction ( ! =ce ( attraction on ! ne$le4 ,b !re may be also *anges 9 int5sity ( ?is action2 ! pull may be a little /rong] or a little weak] ?an be=e1 & ^! v>iations are n repres5t$ by any actual movem5t ( ! ne$le1 ?\gh !y c be measur$ by prop] exp]im5ts4 ,we c1 h[ev]1 imag9e !m repres5t$ by a movem5t ( ! end ( ! ne$le if we suppose x made ( ela/ic mat]ial1 s t x w\ld l5g!n :5 ! =ce 0 great] & contract slightly :5 ! =ce 0 less4 ,if a p5cil 7 atta*$ to ! end ( su* an ela/ic ne$le s z to make a m>k on a %eet ( pap]1 & if = a mom5t we exclude ! up & d[n movem5ts1 ! p5cil w\ld describe dur+ ! day a curve on ! pap]1 z ! end ( ! ne$le swung backw>ds & =w>ds ) ! *ange 9 direction1 & mov$ across ! direction ( sw+ ) ! *ange 9 int5sity4 ,n[ :5 curves ( ?is k9d are describ$ = a day 9 ea* mon? ( ! ye>1 !re is a /rik+ diff]5ce betwe5 ! =ms ( !m4 ,dur+ ! summ] mon?s !y are1 g5]ally speak+1 comp>atively l>ge & op51 & dur+ ! w9t] mon?s !y are small & close4 ,?is *ange 9 =m is se5 by a glance at ,plate ,,xiii41 :i* gives ! curves ?r\gh\t ! :ole ( "o ye>4 ,let u n[1 in/ead ( =m+ a curve ( ?is k9d = ea* mon?1 =m a s+le av]age curve = ! :ole ye>2 & let u fur!r d ?is = a s]ies ( ye>s4 7,plate ,,xiv47 ,we see t ! curves *ange f ye> to ye> 9 a mann] v simil> to t 9 :i* !y *ange f mon? to mon? 9 any p>ticul> ye>1 & ! law ( *ange is su* t 9 ye>s :5 !re are _m sun-spots we get a l>ge op5 curve simil> to ^? f\nd 9 ! summ]1 :ile = ye>s :5 !re are few sun-spots we get small close curves v l ^? 9 ! w9t]4 ,h5ce we h two def9ite conclusions sugge/$3 fir/ly1 t ! *anges ( =ce are sympa!tic ) ! *anges 9 ! sun-spots2 & secondly1 t times ( maximum sun-spots correspond to summ]1 & times ( m9imum to w9t]4 ,& "h ,i mu/ admit t ?is is ab\t z f> z we h got at pres5t 9 ! inve/igation ( ?is relation%ip4 ,:y ! ne$le behaves 9 ?is way we h z yet only ! v vague/ ideas2 sugge/ions ( diff]5t k9ds h c]ta9ly be5 put =w>d1 b none ( !m z yet c be said to h mu* evid5ce 9 fav\r ( its be+ ! true "o4 ,= our pres5t purpose1 h[ev]1 x is suffici5t to note t !re is ?is v real connection1 & t consequ5tly ,s*wabe's sun-spot p]iod may h a v real importance ) reg>d to *anges 9 our e>? itself4 ,illu/ration3 ,,gre5wi* ,,magnetic ,,curves #ahei-fj ,,plate ,,xiii4 ,,gre5wi* ,,magnetic ,,curves ,,= ,,april #ahda-ahfj ,sid5ote3 ,illu/ration ( spuri\s connection4 ,b ,i may p]haps repeat ! ^w ( caution already utt]$ aga9/ ext5d+ )\t suffici5t evid5ce ?is notion ( ! influ5ce ( sun-spots to o!r ph5om5a1 su* z wea!r4 ,a simple illu/ration w p]haps s]ve bett] ?an a long argum5t to %[ bo? ! way 9 :i* mi/akes h be5 made & ! way 9 :i* !y c be se5 to be mi/akes4 ,!re is at ! ,royal ,obs]vatory at ,gre5wi* an in/rum5t = not+ ! direction ( ! w9d1 ! ess5tial "p be+ an ord9>y w9d-vane1 ! movem5ts ( :i* are automatically record$ on a %eet ( pap]4 ,z ! w9d %ifts f nor? to ea/ ! p5cil moves 9 "o direction1 & :5 x %ifts back aga9 t[>ds ! nor? ! p5cil moves 9 ! rev]se way4 ,b sometimes ! w9d %ifts cont9u\sly f nor? to ea/1 s\?1 we/1 & back to nor? aga91 ! vane mak+ a complete revolution2 & ?is causes ! p5cil to move cont9u\sly 9 "o direction1 until :5 ! vane has come to nor? aga91 ! p5cil is f> away f ! conv5i5t place ( record2 on su* occasions x is (t5 necess>y to replace x by h&4 ,!n aga91 ! vane may turn 9 ! opposite direction1 s5d+ ! p5cil inconv5i5tly to ! o!r side ( ! record4 ,dur+ ! ye> x is easy to c\nt ! numb] ( complete *anges ( w9d 9 ei!r direction1 & subtract+ "o numb] f ! o!r1 we get ! excess ( complete revolutions ( ! vane 9 "o direction ov] t 9 ! o!r4 ,n[ if ^! r arbitr>y numb]s are set d[n ye> by ye>1 or plott$ 9 ! %ape ( a diagram1 we get a curve :i* may be comp>$ ) ! sun-spot curve1 & dur+ a p]iod ( no less ?an sixte5 ye>s--f #aheh to #ahgd--!re 0 a rem>kable simil>ity betwe5 ! two diagrams4 ,f ?is evid5ce alone x might fairly be inf]r$ t ! sun-spots _h "s curi\s effect ^u ! wea!r at ,gre5wi*1 traceable 9 ?is extraord9>y way 9 ! *anges ( ! w9d4 ,b ! p>ticul> way 9 :i* ^! *anges are record$ is s arbitr>y t we %\ld naturally feel surprise if !re 0 a real connection betwe5 ! two ph5om5a2 & =tunately !re 7 o!r records prec$+ ^! ye>s & foll[+ !m :i* enabl$ u to te/ ! connection fur!r1 & x 0 f\nd1 z we might naturally expect1 t x 0 n confirm$4 ,on look+ at diagrams 7,plate ,,xv47 = ! p]iods be=e & aft]1 no simil>ity c be trac$ betwe5 ! sun-spot curve & ! w9d-vane curve1 & we inf] t ! simil>ity dur+ ! p]iod fir/ m5tion$ 0 entirely accid5tal4 ,?is %[s t we mu/ be cauti\s 9 accept+1 f a limit$ am\nt ( evid5ce1 a connection betwe5 two ph5om5a z real & e/abli%$2 = x may be purely =tuit\s4 ,we may p>ticul>ly rem>k t x is desirable to h repetitions ?r\gh sev]al complete p]iods in/ead ( "o alone4 ,x is possible to r$uce to ma!matical laws ! rules = caution 9 ?is matt]2 & mu* useful "w has already be5 done 9 ?is direction by ,pr(essor ,s*u/] ( ,man*e/] & o!rs1 ?\gh z yet too little att5tion has be5 paid to _! rules by inve/igators naturally eag] to discov] "s hi!rto un?\ght-( connection betwe5 ph5om5a4 ,sid5ote3 ,faculae foll[ spots & ! *romosph]e4 ,) ?is example ( ! ne$ = caution1 we may return to ph5om5a ( :i* we c c]ta9ly say t !y v>y sympa!tically ) ! sun-spots4 ,r\ghly speak+1 ! :ole hi/ory ( ! sun seems to be b\nd up ) !m4 ,besides ^! d>k pat*es :i* we call spots 7:i*1 by ! way1 are n really d>k b only less bright ?an ! surr\nd+ "p ( ! disc71 !re are pat*es bright] ?an ! re/ :i* h be5 call$ faculae4 ,) ord9>y telescopes1 ei!r visual or photographic1 ^! c g5]ally only be detect$ ne> ! edge ( ! sun's disc2 b ev5 ) ?is limitation x c easily be e/abli%$ t ! faculae v>y 9 numb] & size f ye> to ye> mu* 9 ! same way z ! spots1 & ?is conclusion is amply confirm$ by ! beautiful me?od ( obs]v+ ! faculae ) ! new in/rum5t design$ by ,pr(essor ,hale ( ! ,y]kes ,obs]vatory4 ,) ?is in/rum5t1 call$ a spectroheliograph1 x is possible to photograph ! faculae 9 all p>ts ( ! sun's disc1 & ?us to obta9 a mu* m complete hi/ory ( !m1 & !re is no d\bt :atev] ( _! v>iation sympa!tically ) ! spots4 ,nor is !re any d\bt ab\t simil> v>iations 9 o!r p>ts ( ! sun :i* we _c see at all ) ord9>y telescopes1 except on ! occasions :5 ! sun is totally eclips$4 ,r\ghly speak+1 ^! outly+ portions ( ! sun consi/ ( two k9ds1 ! *romosph]e & ! corona1 ! =m] look+ l an irregul> close coat+ ( ! ord9>y sun1 & ! latt] l a pe>ly halo ( light ext5d+ to _m diamet]s ( ! sun's disc1 b n ) any v regul> =m4 ,illu/ration3 ,,plate ,,xv4 ,,smoo!d ,,sunspot ,,curve 7,,wolf7 ,,comp>$ ,,) ,,! ,,numb] ,,( ,,turns ,,made ,,9 ,,ea* ,,ye> ,,by ,,! ,,osl] ,,anemomet] ,,vane ,,( ,,! ,,royal ,,obs]vatory1 ,,gre5wi* 7,,! ,,excess ,,( ,,! ,,direct ,,turns 7,d7 ,,ov] ,,! ,,retrograde ,,turns 7,r7 ,,or ,,vice ,,v]sa47 ,,! ,,upp] ,,curve ,,is ,,9 ,,ea* ,,case ,,! ,,sunspot ,,curve1 ,,! ,,l[] ,,! ,,vane ,,curve4 ,,! ,,break ,,9 #ahhb ,,9 ,,! ,,vane ,,curve ,,is ,,due ,,to ,,! ,,omission ,,( ,,evid5tly ,,accid5tal ,,turns ,,f ,,t ,,date4 ,! *romosph]e1 f :i* %oot out ! prom95ces or r$ flames1 c n[ be obs]v$ )\t an eclipse if we employ ! beautiful in/rum5t above-m5tion$1 ! spectroheliograph2 & ,pr(essor ,hale has succe$$ 9 photograph+ spots1 faculae1 & prom95ces all on ! same plate4 ,b al?\gh _m h made ! attempt 7& ,pr(essor ,hale1 p]haps1 a m det]m9$ attempt ?an any man liv+71 no "o has yet succe$$ 9 obta9+ any picture or evid5ce ( ! exi/5ce ( ! corona except+ on ! occasion ( a total sol> eclipse4 ,sid5ote3 ,eclipses ( sun4 ,sid5ote3 ,total eclipses r>e4 ,n[ ^! occasions are v r>e4 ,!re are two or ?ree eclipses ( ! sun e ye>1 b !y are g5]ally ( ! k9d kn[n z p>tial2 :5 ! moon does inde$ come betwe5 u & ! sun to "s ext5t1 b only cuts (f a portion ( 8 light--a clean-cut black disc is se5 to encroa* m or less on ! surface ( ! sun4 ,mo/ ( u h _h an opportunity ( see+ a p>tial eclipse1 probably m ?an once2 b few h se5 a total eclipse4 ,= ?is ! moon mu/ come ) great exactness c5trally betwe5 u & ! sun2 & ! spot :]e ?is condition is fulfill$ completely only cov]s a few hundr$ miles ( ! e>?'s surface at "o mom5t4 ,z ! e>? turns r\nd1 & z ! moon revolves 9 its orbit1 ?is pat* f :i* ! sun is totally eclips$ travels ov] ! e>?'s surface1 m>k+ out a track "s ?\s&s ( miles 9 l5g? possibly1 b /ill n m ?an #bjj miles wide2 & 9 ord] to see ! sun totally eclips$ ev5 on ! r>e occasions :5 x is possible at all 7=1 z already rem>k$1 9 ! majority ( cases ! eclipse is only p>tial71 we mu/ occupy "s /ation 9 ?is n>r[ belt or track1 :i* (t5 tantalis+ly passes ov] ei!r ! ocean or "s regions n easily accessible to civilis$ man4 ,moreov]1 if we travel to su* fav\r$ spots ! :ole "t dur+ :i* ! sun is totally eclips$ _c exce$ a few m9utes1 & h5ce obs]vations are made "u r hurri$ & try+ conditions4 ,9 ^! mod]n days ( photography x is easi] to take advantage ( ^! preci\s mom5ts ?an x us$ to be :5 !re 0 only ! eye & memory ( an excit$ obs]v] to rely ^u4 ,x is p]haps n surpris+ t "s ( ! evid5ce collect$ on ^! e>li] occasions 0 conflict+2 b n[adays ! obs]v]s1 g5]ally speak+1 direct _! en]gies 9 ! fir/ place to m\nt+ accurately 9 position photographic app>atus ( diff]5t k9ds1 ea* item ( x specially design$ to settle "s p>ticul> problem 9 ! mo/ feasible way2 secondly1 to rehe>s+ v c>efully ! exact programme ( exposures necess>y dur+ ! critical few m9utes2 & f9ally1 to secur+ ^! photographs ) z few mi/akes z possible :5 ! preci\s mom5ts actually arrive4 ,ev5 !n ! :ole ( _! ef=ts are q likely to be r5d]$ unavail+ by a pass+ cl\d2 & bitt] is ! disappo9tm5t :51 aft] travell+ ?\s&s ( miles1 & sp5d+ mon?s 9 prep>ation1 ! :ole ent]prise ends 9 no?+ ow+ to "s caprice ( ! wea!r4 ,sid5ote3 ,corona foll[s spots4 ,h5ce x w easily be imag9$ t our k ( ! corona1 ! "p ( ! sun :i* we c /ill only /udy on occasions ( a total sol> eclipse1 advances b sl[ly4 ,dur+ ! la/ tw5ty ye>s !re has be5 altoge!r sc>cely half-an-h\r available = ?is rese>*1 ?\gh x may fairly be said t ! v be/ possible use has be5 made ( t half-h\r4 ,&1 :at is ( importance = our imm$iate purpose1 x has gradually be5 e/abli%$ by comp>+ ! photographs ( "o eclipse ) ^? ( ano!r1 t ! corona itself und]goes di/9ct *anges 9 =m 9 ! same p]iod :i* gov]ns ! *anges ( sun-spots4 ,:5 !re are _m sun-spots ! corona spreads out 9 all directions f ! edge ( ! sun's disc2 :5 !re are few sun-spots ! corona ext5ds v mu* fur!r 9 ! direction ( ! sun's equator1 s t at sun-spot m9imum !re is an appe>ance ( two huge w+s4 ,al?\gh ! evid5ce is necess>ily collect$ 9 a scrappy mann]1 by ?is "t !re is suffici5t to remove ?is relation%ip out ( ! region ( m]e suspicion1 & to give x a well-e/abli%$ place 9 our k ( ! sun's surr\nd+s4 ,sid5ote3 ,corona may influ5ce magnets4 ,n[ ! corona ( ! sun may be comp>$ to "s r>e animal :i* we only see by pay+ a visit to "s di/ant l&1 & may consid] ourselves ev5 !n =tunate to get a glimpse (2 & x might be ?\ght t ! habits ( su* an animal are n likely to be ( any great importance 9 our ev]yday life4 ,b s f> f ?is be+ ! case 9 reg>d to ! corona1 x is m ?an possible t ! k ( its *anges may be ( vital int]e/ to u4 ,i h already said t1 z yet1 we h no satisfactory acc\nt ( ! reason :y *anges 9 sun-spots seem to influ5ce *anges 9 our magnets on ! e>?2 b "o ( ! !ories put =w>d 9 explanation1 & "o by no means ! lea/ plausible1 is t ?is influ5ce may come1 n f ! sun-spots !mselves1 b f "s o!r sol> ph5om5on :i* v>ies 9 sympa?y ) !m2 & 9 p>ticul> t x may come f ! corona4 ,^! w+s :i* rea* out at sun-spot m9imum c be se5 to ext5d a consid]able di/ance1 & !re is no reason to suppose t !y actually cease at ! po9t :]e !y become too fa9t = u to detect !m fur!r2 !y may ext5d q z f> z ! e>? itself & ev5 beyond2 & !y may be ( su* a nature z to influ5ce our magnets4 ,z ! e>? revolves r\nd ! sun x may sometime plunge into !m1 to em]ge lat] & pass above or bel[ !m2 z aga9 ! w+s spread !mselves at sun-spot m9imum & seem to %r9k at maximum1 s our magnets may respond by sympa!tic ?\gh v small vibrations4 ,h5ce x is q possible t ! corona is directly influ5c+ ! magnetic *anges on ! e>?4 ,sid5ote3 ,possible importance ( corona4 ,b x may be urg$ t ^! *anges are s slight z to be m]ely ( sci5tific int]e/4 ,t may be true to-day1 b :o w be bold en\gh to say t x w be true to-morr[8 ,if we are ?9k+ ( practical utility alone1 we may rememb] t two great =ces ( ,nature :i* we h *a9$ into ! s]vice ( man1 /eam & electricity1 put =? orig9ally ! mo/ feeble manife/ations1 :i* might readily h be5 despis$ z valueless2 b by c>eful att5tion to prop] conditions results ( ov]:elm+ practical importance h be5 obta9$ f ^! =ces1 :i* might h be51 & = _m c5turies 71 neglect$ z too trivial to be wor? att5tion4 ,rec5tly ! _w has be5 />tl$ by ! discov]y ( new elem5ts1 su* z radium1 ^: v exi/5ce 0 only detect$ by a triumph ( sci5tific acut5ess 9 inve/igation1 & yet :i* promise to yield influ5ces on our lives :i* may ov]:elm 9 importance all t has gone be=e4 ,& simil>ly x may be t ^! magnetic *anges1 :5 prop]ly int]pret$ or develop$1 may become ( an importance 9 ! future out ( all proportion to ! att5tion :i* !y h hi!rto attract$4 ,h5ce1 al?\gh p]haps suffici5t has already be5 e/abli%$ to %[ ! imm5se consequ5ces :i* fl[ f ,s*wabe's rem>kable discov]y ( ! p]iodicity 9 sol> spots1 we may be z yet only on ! ?re%old ( its real value4 ,f :at little causes great ev5ts spr+6 ,h[ little c ,s*wabe h realis$1 :5 he began to po9t 8 mode/ little telescope at ! sun1 & to c\nt ! numb] ( spots--! despis$ spots :i* he _h be5 assur$ 7 ( no int]e/ & exhibit$ no laws1 & 7 g5]ally unpr(itable--t he 0 tak+ ! fir/ /ep 9 ! inv5tion ( ! great sci5ce ( ,sol> ,physics6--a sci5ce :i* is1 ,i am glad to say1 occupy+ at ! pres5t mom5t s mu* ( ! att5tion1 n only ( ! great ,y]kes ,obs]vatory1 b ( _m o!r obs]vatories scatt]$ ov] ! globe4 ,,*apt] ,,vi ,,! ,,v>iation ,,( ,,latitude ,if we %\ld desire to classify discov]ies 9 ord] ( m]it1 we mu/ und\bt$ly give a high place to ^? :i* are made "u direct disc\ragem5ts4 ,9 ! la/ *apt] we saw t ,s*wabe ent]$ ^u 8 "w "u conditions ( ?is k9d1 x be+ ! op9ion ( exp]i5c$ a/ronom]s :o _h look$ at ! facts t !re 0 no?+ ( int]e/ to be got by wat*+ sun-spots4 ,9 ! pres5t *apt] ,i propose to deal ) a discov]y made 9 ! v tee? ( ! unanim\s op9ion ( ! a/ronomical _w by an ,am]ican amateur1 ,mr4 ,s4 ,c4 ,*&l] ( ,cambridge 7,massa*usetts74 ,x is my purpose to all[ him to himself expla9 ! /eps ( ?is discov]y by giv+ extracts f ! magnific5t s]ies ( pap]s :i* he contribut$ to ! ,a/ronomical ,j\rnal on ! subject 9 ! ye>s #ahia-id1 b x may help 9 ! und]/&+ ( ^! extracts if ,i give a brief summ>y ( ! facts4 ,& ,i w fir/ expla9 :at is meant by ! ,v>iation ( ,latitude4 ,sid5ote3 ,latitude4 ,sid5ote3 ,precession4 ,we are all famili> ) ! exi/5ce ( a c]ta9 /> 9 ! heav5s call$ ! ,pole ,/>1 & we "k t at any p>ticul> place x is se5 con/antly 9 ! nor? at a def9ite height above ! horizon1 :i* is ! latitude ( ! place4 ,:5 wat*$ c>efully ) a telescope x is f\nd to be n absolutely /ation>y1 b to describe a small circle 9 ! heav5s day by day1 or r night by night4 ,^! simple facts are b\nd up ) ! ph5om5on ( ! e>?'s rotation 9 ?is way3 ! axis ab\t :i* x is rotat+ po9ts to ! c5tre ( t little circle1 & any *ange 9 ! position ( ! axis c !re=e be det]m9$ by obs]v+ ^! motions ( ! ,pole ,/>4 ,su* *anges may be ( two k9ds3 fir/ly1 we might f9d t ! size ( ! circle increas$ or dim9i%$1 & ?is w\ld mean t ! e>?'s axis 0 po9t+ f>!r away f ! ,pole ,/> or ne>] to x--po9t+1 t is to say1 9 a diff]5t direction 9 space4 ,?is actually happ5s 7z has be5 kn[n = "s ?\s&s ( ye>s7 ow+ to ! ph5om5on call$ precession2 ! circle describ$ by our ,pole ,/> is at pres5t gett+ a little small]1 b x w ultimately increase 9 size1 & aft] ?\s&s ( ye>s become s l>ge t ! ,pole ,/> w entirely lose its "* z a /eady guide to ! ,nor?4 ,sid5ote3 ,*ange ( latitude4 ,sid5ote3 ,tw5ty ye>s ago disbeliev$4 ,secondly 7& ?is is :at m imm$iately conc]ns u71 ! c5tre ( ! circle may alt] its position & be no long] at ! same height above ! horizon ( any giv5 place4 ,?is w\ld mean t ! e>?'s axis 0 %ift+ 9 ! e>? itself--t ! ,nor? ,pole :i* our explor]s g to seek is n rema9+ 9 ! same place4 ,t x does n *ange appreciably 9 position we "k f famili> exp]i5ce2 our climates1 = in/ance1 w\ld suff] consid]ably if !re 7 any l>ge *anges4 ,b a/ronom]s are conc]n$ ) m9ute *anges :i* w\ld n h any appreciable effect on climate1 & ! "q has long be5 be=e !m :e!r1 putt+ aside l>ge movem5ts1 !re 7 any m9ute v>iations 9 position ( ! ,nor? ,pole4 ,tw5ty ye>s ago ! answ] to ?is "q w\ld h be5 giv5 decid$ly 9 ! negative2 x 0 consid]$ z c]ta9 t ! ,nor? ,pole did n move at all )9 ! limits ( our mo/ ref9$ a/ronomical obs]vations4 ,accept$ !ory seem$ to indicate t any movem5ts mu/ 9 any case recur aft] a p]iod ( t5 mon?s1 & c>eful discussion ( ! obs]vations %[$ t !re 0 no oscillation 9 su* a p]iod4 ,n[ we "k t ! !ory itself 0 wrong1 or r 0 f\nd$ ^u a mi/ak5 assumption2 & t ! facts :5 prop]ly exam9$ %[ cle>ly a di/9ct movem5t ( ! ,nor? ,pole1 n a v l>ge "o1 = all its movem5ts take place )9 ! area occupi$ by a mod]ate-siz$ room1 b /ill a movem5t easily measurable by a/ronomical obs]vations1 & ,mr4 ,*&l] 0 ! fir/ to po9t out ! law ( ^! movem5ts1 & v possibly ! fir/ to suspect !m4 ,sid5ote3 ,*&l]'s pap]s4 ,) ^! few words ( explanation ,i w let ,mr4 ,*&l] tell 8 own /ory4 ,8 fir/ pap] appe>$ 9 ! ,a/ronomical ,j\rnal 9 ,novemb] #ahia1 & is c\rage\sly head$1 ,on ! ,v>iation ( ,latitude--,i say c\rage\sly1 because at t "t x 0 believ$ t ! latitude did n v>y1 & ,mr4 ,*&l] himself 0 only 9 possession ( a small portion ( ! facts4 ,!y unravell$ !mselves z he w5t =w>d2 b he felt t he _h firm hold ( ! end ( ! ?read1 & he fac$ ! _w confid5tly 9 t belief4 ,he beg9s ?us3-- ,sid5ote3 ,fir/ signs ( *ange4 ,9 ! det]m9ation ( ! latitude ( ,cambridge#e ) ! ,almucant>1 ab\t six ye>s & a half ago1 x 0 %[n t ! obs]v$ values1 arrang$ accord+ to nights ( obs]vation1 exhibit$ a decid$ & curi\s progression ?r\gh\t ! s]ies1 ! e>li] values be+ small1 ! lat] ones l>ge1 & ! range f ,novemb] #ahhd to ,april #ahhe be+ ab\t f\r-t5?s ( a second4 ,!re 0 no kn[n or imag9able in/rum5tal or p]sonal cause = ?is ph5om5on1 yet ! only alt]native seem$ to be an inf]5ce t ! latitude _h actually *ang$4 ,?is seem$ at ! "t too bold an inf]5ce to place ^u record1 & ,i !re=e left ! results to speak = !mselves4 ,! subsequ5t cont9uation ( ! s]ies ( obs]vations to ! end ( ,june #ahhe gave a maximum ab\t ,may #a1 :ile ! discussion ( ! previ\s obs]vations f ,may to ,novemb] #ahhd gave a m9imum ab\t ,septemb] #a1 indicat+ a range ( #j4g )9 a half-p]iod ( ab\t sev5 mon?s4 ,mr4 ,*&l] !n gives "s figures 9 support ( ^! /atem5ts1 pres5t+ !m ) ! cle>ness :i* is s well m>k$ a feature ( ! :ole s]ies ( pap]s1 & concludes ?is introductory pap] z foll[s3-- ,x ?us appe>s t ! app>5t *ange 9 ! latitude ( ,cambridge is v]ifi$ by ?is discussion ( m abundant mat]ial4 ,! presumption t x is real1 on ?is det]m9ation alone1 w\ld ju/ify fur!r inquiry4 ,sid5ote3 ,confirm$ 9 ,europe4 ,curi\sly en\gh ,dr4 ,kue/n]1 9 8 det]m9ation ( ! ab]ration f a s]ies ( obs]vations co9cid5t 9 "t ) ^? ( ! ,almucant>1 came ^u simil> anomalies1 & 8 results1 publi%$ 9 #ahhh1 furni% a c\nt]p>t to ^? :i* ,i _h po9t$ out 9 #ahhe4 ,! v]ification af=d$ by ! rec5t p>allel det]m9ations at ,b]l91 ,prague1 ,potsdam1 & ,pulk[a1 :i* %[ a mo/ surpris+ & satisfactory accordance1 z to ! "* ( ! *ange1 9 range & p]iodicity1 ) ! ,almucant> results1 has l$ me to make fur!r inve/igations on ! subject4 ,!y seem to e/abli% ! nature ( ! law ( ^? *anges1 & ,i w proce$ to pres5t !m 9 due ord]4 ,! second pap] appe>$ on ,novemb] #bc1 & op5s ) ! foll[+ brief /atem5t ( 8 g5]al results at t "t3-- ,sid5ote3 #dbg days' p]iod4 ,be=e ent]+ ^u ! details ( ! inve/igations spok5 ( 9 ! prec$+ numb]1 x is conv5i5t to say t ! g5]al result ( a prelim9>y discussion is to %[ a revolution ( ! e>?'s pole 9 a p]iod ( #dbg days1 f we/ to ea/1 ) a radius ( ?irty feet1 measur$ at ! e>?'s surface4 ,assum+ provisionally1 = ! purpose ( /atem5t1 t ?is is a motion ( ! nor? pole ( ! pr9cipal axis ( in]tia ab\t t ( ! axis ( rotation1 ! direction ( ! =m] f ! latt] lay t[>ds ! ,gre5wi* m]idian ab\t ! beg9n+ ( ! ye> #ahij4 ,?is1 ) ! p]iod ( #dbg days1 w s]ve to fix approximately ! relative positions ( ^! axes at any o!r "t1 = any giv5 m]idian4 ,x is n possible at ?is /age ( ! inve/igation to be m precise1 z !re are facts :i* appe> to %[ t ! rotation is n a p]fectly uni=m "o1 b is subject to secul> *ange1 & p]haps irregul>ities )9 brief spaces ( "t4 ,sid5ote3 ,contr>y to receiv$ views4 ,x is almo/ impossible1 n[ t we h become famili> ) ! ideas convey$ 9 ?is p>agraph1 to und]/&1 or ev5 fully to rememb]1 ! impression produc$ by !m at ! "t2 ! s5sation caus$ 9 "s qu>t]s1 & ! ridicule excit$ 9 o!rs4 ,!y 7 9 flat contradiction to all accept$ views2 & x 0 believ$ t ^! views 7 n only !oretically s\nd1 b _h be5 matur$ by a ?or\gh exam9ation ( obs]vational evid5ce4 ,! only p]iod 9 :i* ! e>?'s pole c\ld revolve 0 believ$ to be t5 m\?s2 & "h 0 ,mr4 ,*&l] proclaim+1 app>5tly )\t any idea t he 0 contradict+ ! laws ( dynamics1 t x 0 revolv+ 9 f\rte5 mon?s6 ,! radius ( its pa? _h be5 f\nd to be ins5sible by c>eful discussion ( obs]vations1 & n[ he proclaim$ a s5sible radius o,l ?irty feet4 ,f9ally1 he _h ! audacity to ann\nce a v>iable p]iod1 to :i* !re 0 no?+ at all correspond+ 9 ! ma!matical possibilities4 ,?is 0 ! bitt]e/ pill ( all4 ,ev5 aft] ,pr(essor ,newcomb _h %[n u h[ to swall[ ! o!r two1 he c\ld n recomm5d any attempt at ! ?ird1 z we %all pres5tly see2 & ,mr4 ,*&l] 0 fa9 ultimately to gild x a little be=e x c\ld be gulp$4 ,sid5ote3 ,pulk[a puzzle solv$1 also ,wa%+ton4 ,b ?is is anticipat+1 & x is our int5tion to foll[ pati5tly ! evid5ce adduc$ 9 support ( ! above /atem5ts1 made ) su* spl5did confid5ce to a totally disbeliev+ _w4 ,mr4 ,*&l] fir/ exam9es ! obs]vations ( ,dr4 ,kue/n] ( ,b]l91 quot$ at ! end ( 8 la/ pap]1 & %[s h[ well !y are suit$ by ! exi/5ce ( a v>iation 9 ! latitude ( #dbg days2 & t ?is new fact is add$--:5 ! ,cambridge 7,u4,s4,a47 latitudes 7 ! smalle/ ^? ( ,b]l9 7 ! l>ge/1 & vice v]sa1 z w\ld cle>ly be ! case if ! ph5om5on 0 due to a motion ( ! e>?'s pole2 = if x mov$ ne>] ,am]ica x mu/ move fur!r f ,europe4 ,he !n exam9es a long s]ies ( obs]vations made 9 ! ye>s #ahfd-ahgc at ,pulk[a1 ne> ,/4 ,pet]sburg1 & aga9 f9ds satisfactory confirmation ( 8 law ( v>iation4 ,n[ x _h long be5 kn[n t !re 0 some?+ curi\s ab\t ^! obs]vations1 b no "o c\ld tell :at x 04 ,! key (f]$ by ,mr4 ,*&l] fitt$ ! lock exactly1 & ! anomalies :i* _h be5 a puzzle 7 remov$4 ,?is 0 9 itself a great triumph2 b !re 0 ano!r to come1 :i* we may let ,mr4 ,*&l] describe 9 8 own words3-- ,9 #ahfb ,pr(essor ,hubb>d began a s]ies ( obs]vations ( a ,lyrae at ! ,wa%+ton ,obs]vatory ) ! prime v]tical transit in/rum5t1 = ! purpose ( det]m9+ ! con/ants ( ab]ration & nutation & ! p>allax ( ! />4 ,! me?ods ( obs]vation & r$uction 7 con=m$ to ^? us$ ) su* success by ,w4 ,/ruve4 ,aft] ,hubb>d's dea? ! s]ies 0 cont9u$ by ,pr(essors ,newcomb1 ,hall1 & ,h>kness until ! beg9n+ ( #ahfg4 ,pr(essor ,hall describes ^! obs]vations z ! mo/ accurate det]m9ations ( decl9ation ev] made at ! ,naval ,obs]vatory4 ,! probable error ( a decl9ation f a s+le transit 0 -#j4ada1 & judg+ f ! accid5tal errors1 ! s]ies ought to give tru/wor?y results4 ,^u r$uc+ !m1 h[ev]1 x 0 f\nd t "s abnormal s\rce ( error exi/$1 :i* result$ 9 anomal\s values ( ! ab]ration-con/ant 9 ! diff]5t ye>s1 & a negative p>allax 9 all4 ,a c>eful v]ification ( ! processes ( r$uction fail$ to discov] ! cause ( ! tr\ble1 & ,pr(essor ,hall says t ! results mu/ /& z pr9t$1 & t probably "s annual di/urbance 9 ! obs]vations or ! in/rum5t occurr$1 :i* w nev] be expla9$1 & :i* r5d]s all d$uctions f !m unc]ta94 ,! tr\ble c\ld n be connect$ ) p]sonal equation1 ! anomalies rema9+ :5 ! obs]vations ( ! f\r obs]v]s :o took "p 7 sep>ately treat$4 ,nor1 z ,pr(essor ,hall po9ts out1 w ! !oretical t5-mon? p]iod 9 ! latitude furni% ! explanation4 ,x is manife/1 h[ev]1 t if ! #dbg-;day p]iod exi/s1 its effect ought to appe> di/9ctly 9 decl9ation-measurem5ts ( su* high degree ( excell5ce z ^! presumably 71 &1 z ,i hope satisfactorily to %[1 actually are4 ,:5 ?is v>iation is tak5 into acc\nt ! obs]vations w unque/ionably v9dicate ! high expectations ent]ta9$ ) reg>d to !m by ! accompli%$ & skilful a/ronom]s :o design$ & c>ri$ !m out4 ,sid5ote3 ,direction ( revolution ( ,pole4 ,sid5ote3 ,example ( results4 ,f ?is g5]al acc\nt ,i am exclud+ te*nical details & figures1 & un=tunately a great deal is !reby lo/4 ,we lose ! s5se ( conviction :i* ! long r[s ( accordant figures =ce ^u u1 & we lose ! opportunities ( admir+ bo? ! a/oni%+ am\nt ( "w done & ! beautiful way 9 :i* ! mat]ial is h&l$ by a ma/]4 ,b ,i am tempt$ to give "o v small illu/ration ( ! num]ical results f ne> ! end ( ! pap]4 ,aft] discuss+ ! ,wa%+ton results1 & amply fulfill+ ! promise made 9 ! prec$+ extract1 ,mr4 ,*&l] comp>es !m ) ! ,pulk[a results1 & %[s t ! ,e>?'s ,pole mu/ be revolv+ f we/ to ea/1 & n f ea/ to we/4 ,& !n he writes d[n a simple =mula repres5t+ ?is motion1 & comp>es 8 =mula ) ! obs]vations4 ,he gives ! results 9 seconds ( arc1 b = ! b5efit ( ^? n famili> ) a/ronomical measurem5ts we may readily conv]t ^! into feet2 & 9 ! foll[+ tables are %[n ! di/ances ( ! ,e>?'s ,pole 9 feet f its av]age position1#f z obs]v$ at ,wa%+ton & at ,pulk[a1 & ! same di/ances calculat$ accord+ to ! =mula :i* ,mr4 ,*&l] 0 able to write d[n at ?is e>ly /age4 ,! signs & - ( c\rse indicate opposite directions ( displacem5t3-- ,,wa%+ton4 ,deviation ( ,pole4 ------------------------------------- ,date4 ,obs]v$4 ,=mula4 ------------------------------------- #ahfd1 ,dec4 #bh -#bh feet -#bc feet #ahfe1 ,m>4 #ai - #a -#ab ,june #a #ae #ab ,aug4 #aa #bb #bc ,oct4 #i #aa #ae ,dec4 #ac -#ag - #f ------------------------------------- ,,pulk[a4 ,deviation ( ,pole4 ------------------------------------- ,date4 ,obs]v$4 ,=mula4 ------------------------------------- #ahfe1 ,july #be -#ah feet -#ab feet ,sept4 #i #c #c ,nov4 #bb #bf #bb #ahff1 ,feb4 #bb #ah #ac ,june #d -#aa -#ah ,july #ag -#af -#bc ------------------------------------- ,( c\rse ! figures are n exact 9 e case1 b !y are nev] _m feet wrong2 & x may well be imag9$ t x is a difficult ?+ to d$uce1 ev5 f ! mo/ ref9$ obs]vations1 ! position ( ! e>?'s pole to )9 a foot4 ,! difficulty is exactly ! same z t ( measur+ ! l5g? ( an object #cjj miles away to )9 an in*6 ,mr4 ,*&l] w9ds up 8 second pap] ?us3-- ,we ?us f9d t ! comp>ison ( ! simultane\s s]ies at ,pulk[a & ,wa%+ton1 #ahfc-ahfg1 leads to ! same conclusion z t already drawn f ! simultane\s s]ies at ,b]l9 & ,cambridge1 #ahhd-ahhe4 ,! direction ( ! pol> motion may !re=e be look$ ^u z e/abli%$ ) a l>ge degree ( probability4 ,9 ! next pap] ,i w pres5t ! results d]iv$ f ,,pet]s1 ,,/ruve1 ,,bradley1 & v>i\s o!r s]ies ( obs]vations1 aft] :i* ! results ( all w be br\ght to be> ^u ! det]m9ation ( ! be/ num]ical values ( ! con/ants involv$4 ,sid5ote3 ,bradley's obs]vations4 ,sid5ote3 ,latitude v>i$ 9 twelve mon?s !n4 ,! results 7 n1 h[ev]1 pres5t$ 9 ?is ord]4 ,9 ! next pap]1 :i* appe>$ on ,decemb] #bc1 #ahia1 ,mr4 ,*&l] beg9s1 ) ! "w ( ,bradley1 ! v s]ies ( obs]vations at ,kew & ,wan/$ :i* l$ to ! discov]ies ( ab]ration & nutation1 & :i* we consid]$ 9 ! ?ird *apt]4 ,he fir/ %[s t1 not)/&+ ! obvi\s accuracy ( ! obs]vations1 !re is "s unexpla9$ discordance4 ,! v con/ant ( ab]ration :i* ,bradley discov]$ f !m diff]s by half-a-second ( arc f our be/ mod]n det]m9ations4 ,attempts h be5 made to ascribe ! discordance to *anges 9 ! in/rum5t1 b ,mr4 ,*&l] %[s t su* *anges1 sett+ aside ! fact t ,bradley w\ld almo/ c]ta9ly h discov]$ !m1 w n fit 9 ) ! facts4 ,! facts1 :5 analys$ ) ! skill to :i* we h become accu/om$1 are t !re is a p]iodic sw+ 9 ! results ) a p]iod ( ab\t a ye>1 & n f\rte5 mon?s1 z be=e1 a result s curi\s1 z he admits1 t if we f\nd no fur!r support1 x might lead u to di/ru/ ! above reason+1 & ?r[ u back to ! possibility t1 aft] all1 ,,bradley',s obs]vations may h be5 vitiat$ by "s k9d ( annual in/rum5tal error4 ,b x w abundantly appe>1 :5 ,i h _h ! opportunity to pr9t ! d$uctions f all ! o!r s]ies ( obs]vations d[n to ! pres5t "t1 t ! inf]5ce ( an increase 9 ! p]iod ( pol> revolution is firmly e/abli%$ by _! concurr5t te/imony4 ,we %all pres5tly return to ?is curi\s result1 :i* might well h dismay$ a less det]m9$ rese>*] ?an ,mr4 ,*&l]1 b :i* only l$ him on to r5ew$ ex]tions4 ,! results obta9$ f ,bradley's obs]vations may be put 9 ! =m ( a diagram ?us3-- ,illu/ration3 ,,fig4 #g4 ,x w be se5 t ! maxima & m9ima fall 9 ! spr+ & autumn1 & ?is fact alone seem$ to %[ t ! effect c\ld n be due to temp]ature1 = we %\ld expect ! greate/ effect 9 t case 9 w9t] & summ]4 ,x c\ld n be due to ! p>allax ( ! />s = :i* ,bradley began 8 se>*1 = />s 9 diff]5t qu>t]s ( ! heav5s w\ld !n be diff]5tly affect$1 & ?is 0 n ! case4 ,!re rema9s1 conclud$ ,mr4 ,*&l] aft] full discussion1 ! only natural conclusion ( an actual displacem5t ( ! z5i?1 9 o!r words1 a *ange ( latitude4 ,& he concludes ?is pap] ) ! foll[+ f9e passage3-- ,s f>1 !n1 z ! results ( ?is incomp>able s]ies ( obs]vations at ,kew & ,wan/$1 consid]$ by !mselves alone1 c n[ be /at$1 ! p]iod ( ! pol> rotation at t epo* appe>s to h be5 probably some:at ov] a ye>1 & c]ta9ly %ort] by ab\t two mon?s ?an x is at ! pres5t "t4 ,! range ( ! v>iation 0 app>5tly 9 ! neighb\rhood ( a second ( arc1 or consid]ably l>g] ?an t %[n by ! be/ mod]n obs]vations4 ,sid5ote3 ,bradley's greatness4 ,be=e tak+ leave ( ^! obs]vations = ! pres5t ,i _c =be> to speak ( ! pr(\nd impression :i* a /udy ( !m leaves ^u ! m9d1 & ! satisfaction :i* all a/ronom]s mu/ feel 9 recognis+ t1 besides its fir/ fruits ( ! ph5om5a ( ab]ration & nutation1 we n[ owe also our fir/ k ( ! pol> motion to ?is same immortal "w ( ,bradley4 ,its excell5ce1 highly appreciat$ z x has be51 has /ill be5 hi!rto obscur$ by ! pres5ce ( ?is unsuspect$ ph5om5on4 ,:5 dive/$ ( its effects1 ! wond]ful accuracy ( ?is "w mu/ appe> 9 a f9] light1 & our admiration mu/ be rais$ to high] pit*4 ,go+ back to x aft] "o hundr$ & sixty ye>s seems inde$ l advanc+ into an era ( practical a/ronomy m ref9$ ?an t f :i* we pass4 ,& ?is leads to a sugge/ion wor?y ( s]i\s practical consid]ation--:e!r we c d bett] 9 ! future /udy ( ! pol> rotation1 ?an aga9 to avail ourselves ( ,bradley's me?od1 )\t endang]+ its elegant simplicity & effectiv5ess by attempts at improvem5t1 o!r ?an supply+ c]ta9 means ( in/rum5tal control :i* w\ld )\t d\bt comm5d !mselves to 8 sagaci\s m9d4 ,sid5ote3 ,o!r puzzles expla9$4 ,9 ! next article ,bradley's lat] obs]vations at ,gre5wi*1 ! results ( :i* are n s di/9ct1 w be discuss$2 & also ^? ( ,br9kley at ,dubl91 #ahjh-ac & #ahah-bb4 ,?is w br+ aga9 to ! surface "o ( ! mo/ int]e/+ episodes 9 a/ronomical hi/ory1 ! spirit$ & almo/ acrimoni\s dispute betwe5 ,br9kley & ,pond ) reg>d to /ell> p>allaxes4 ,i hope to %[ t ! hi!rto unsolv$ enigma ( ,br9kley's s+ul> results f9ds its easy solution 9 ! fact ( ! pol> motion4 ,! p]iod ( 8 epo* appe>s to h be5 ab\t a ye>1 & its range m ?an a second4 ,aft]w>ds w foll[ v>i\s discussions already m or less advanc$ t[>ds completion4 ,^! include ,bessel's obs]vations at ,ko5igsb]g1 #ahbj-bd1 ) ! ,rei*5ba* circle1 & 9 #ahdb-dd ) ! ,repsold circle2 ! latitudes d]iv$ f ! pol>-po9t det]m9ations ( ,/ruve & ,ma$l] ) ! ,dorpat circle1 #ahbb-ch2 ,/ruve's obs]vations = ! det]m9ation ( ! ab]ration2 ,pet]s' obs]vations ( ,pol>is1 #ahda-dc1 ) ! v]tical-circle2 ! results obta9$ f ! reflex z5i?-tube at ,gre5wi*1 #ahcg-ge1 ^: s+ul> anomalies c be ref]r$ 9 l>ge "p to our pres5t ph5om5on1 complicat$ ) in/rum5tal error1 to :i* until n[ !y h be5 exclusively attribut$2 ! ,gre5wi* transit-circle results1 #ahea-fe1 9 :i* case1 h[ev]1 a simil> complication & ! l>ge accid5tal errors ( obs]vation seem to fru/rate ef=ts to get any p]t95t results2 ! ,b]l9 prime-v]tical obs]vations ( ,wey] & ,bru5n[1 #ahde-df1 9 :i* ,i hope to %[ t ! p>allax ( beta ,draconis d]iv$ f !m is simply a record ( ! *ange ( latitude2 ! conflict+ latitude det]m9ations at ,cambridge1 ,engl&2 ! ,wa%+ton obs]vation ( ,pol>is & o!r close ,pol>s1 #ahff-hg1 ) ! transit-circle2 also ^? at ,melb\rne1 #ahfc-hd1 a portion ( :i* h already be5 drawn ^u 9 ! la/ numb] ( ! ,j\rnal1 & "s o!rs4 ,:ile ! li/ is a consid]able "o1 ,i %all be able to compress ! /atem5t ( results = _m ( ! s]ies into a %ort space4 ,sid5ote3 ,provisional nature ( results4 ,9 connection ) ?is synopsis ( ! scope ( ! inve/igations1 "o or two p>ticul>s may be ( int]e/1 :i* at ! pres5t writ+ seem to =e%ad[ ! probable outcome4 ,i beg1 h[ev]1 t ! /atem5t w be reg>d$ m]ely z a provisional "o4 ,fir/1 :ile ! p]iod is manife/ly subject to *ange1 z has already once or twice be5 intimat$1 ,i h hi!rto fail$ 9 trac+ ! v>iations to any regul> law1 expressible 9 a num]ical =mula4 ,inde$1 ! g5]al impression produc$ by a /udy ( ^! *anges 9 ! l5g? ( ! p]iod is t ! cause :i* produces !m op]ates caprici\sly to a c]ta9 degree1 al?\gh ! av]age effect = a c5tury has be5 to dim9i% ! velocity ( ! revolution ( ! pole4 ,h[ f> ?is impression is due to ! unc]ta9ty ( ! obs]vations1 & to ! complication ( ! ph5om5on ) o!r p]iodical *anges ( a purely in/rum5tal k9d1 ,i _c say4 ,almo/ all ( ! s]ies ( any ext5t :i* h be5 exam9$1 h ! peculi>ity t !y manife/ ! p]iodicity q uni=mly & di/9ctly = a numb] ( ye>s1 !n = a :ile obscurely4 ,9 "s cases1 h[ev]1 :at at fir/ appe>s to be an objective irregul>ity proves n to be s by comp>ison ) ov]lapp+ s]ies at o!r obs]vatories4 ,ano!r *>act]i/ic :i* has /ruck my att5tion1 al?\gh some:at vaguely1 is t ! v>iations 9 ! l5g? ( ! p]iod seem to g h& 9 h& ) simultane\s alt]ations 9 ! amplitude ( ! rotation2 ! %ort] p]iods be+ app>5tly associat$ ) ! l>g] coeffici5ts = ! latt]4 ,! v]ification ( ^! surmises awaits a clos] comp>ative scrut9y1 ! opportunity = :i* w come :5 ! computations are 9 a m =w>d /ate4 ,if confirm$1 ^! obs]vations w af=d a valuable t\*/one1 9 seek+ = ! cause ( a ph5om5on :i* n[ seems to be at v>iance ) ! accept$ laws ( t]re/rial rotation4 ,sid5ote3 ,reception ( discov]y4 ,let u n[ = a few mom5ts turn aside f ! actual rese>* to see h[ ! ann\ncem5t 0 receiv$4 ,x w\ld be ungraci\s to repr9t "h any ( ! e>ly /atem5ts ( incr$ulity :i* f\nd _! way into pr9t1 especially 9 ,g]many4 ,b ! fir/ note ( welcome came f ,simon ,newcomb1 9 ! same numb] ( ! ,a/ronomical ,j\rnal z ! pap] j dealt )1 & ! foll[+ extract w indicate bo? ! difficulties felt 9 receiv+ ,mr4 ,*&l]'s results & ! way 9 :i* ,newcomb /ruck at ! root ( !m4 ,sid5ote3 ,newcomb's explanation4 ,mr4 ,*&l]'s rem>kable discov]y1 t ! app>5t v>iations 9 t]re/rial latitudes may be acc\nt$ = by suppos+ a revolution ( ! axis ( rotation ( ! e>? ar\nd t ( figure1 9 a p]iod ( #dbg days1 is 9 su* disaccord ) ! receiv$ !ory ( ! e>?'s rotation t at fir/ ,i 0 dispos$ to d\bt its possibility4 ,b ,i am n[ able to po9t out a v]a causa :i* af=ds a complete explanation ( ?is p]iod4 ,up to ! pres5t "t ! treatm5t ( ?is subject has be5 ?is3 ,! ratio ( ! mom5t ( in]tia ( ! e>? ar\nd its pr9cipal axis to ! mean ( ! o!r two pr9cipal mom5ts1 admits ( v accurate det]m9ation f ! am\nt ( precession & nutation4 ,?is ratio involves :at we might call1 9 a g5]al way1 ! solid ellipticity ( ! e>?1 or ! ellipticity ( a homog5e\s sph]oid hav+ ! same mom5ts ( in]tia z ! e>?4 ,:5 ! diff]5tial equations ( ! e>?'s rotation are integrat$1 !re appe> two arbitr>y con/ants1 repres5t+ ! position ( any assign$ epo* ( ! axis ( rotation relative to t ( figure4 ,!ory !n %[s t ! axis ( rotation w revolve r\nd t ( figure1 9 a p]iod ( #cjf days1 & 9 a direction f we/ t[>d ea/4 ,! attempts to det]m9e ! value ( ^! con/ants h seem$ to %[ t bo? are z]o1 or t ! axes ( rotation & figure are co9cid5t4 ,sev]al ye>s s9ce1 ,sir ,william ,?omson publi%$ ! result ( a brief computation f ! ,wa%+ton ,prime-,v]tical obs]vations ( alpha ,lyrae :i* ,i made at 8 reque/ & :i* %[$ a coeffici5t #j4je4 ,?is coeffici5t did n exce$ ! possible error ( ! result2 ,i !re=e reg>d$ x z unreal4 ,sid5ote3 ,! =gott5 assumption4 ,! "q n[ arises :e!r ,mr4 ,*&l]'s result c be reconcil$ ) dynamic !ory4 ,i answ] t x c1 because ! !ory :i* assigns #cjf days z ! "t ( revolution is bas$ on ! hypo!sis t ! e>? is an absolutely rigid body4 ,b1 z a matt] ( fact1 ! fluidity ( ! ocean plays an important "p 9 ! ph5om5on1 z does also ! ela/icity ( ! e>?4 ,! comb9$ effect ( ?is fluidity & ela/icity is t if ! axis ( rotation is displac$ by a c]ta9 am\nt1 ! axis ( figure w1 by ! *ang$ action ( ! c5trifugal =ce1 be mov$ t[>d co9cid5ce ) ! new axis ( rotation4 ,! result is1 t ! motion ( ! latt] w be dim9i%$ 9 a correspond+ ratio1 & ?us ! "t ( revolution w be l5g!n$4 ,an exact computation ( ! effect is n possible )\t a k ( ! e>?'s modulus ( ela/icity4 ,b ,i ?9k ! result ( inve/igation w be t ! rigidity d]iv$ f ,mr4 ,*&l]'s p]iod is z great z t claim$ by ,sir ,william ,?omson f ! ph5om5a ( ! tides4 ,sid5ote3 ,b ,*&l]'s "w /ill mi/ru/$4 ,?is 0 v satisfactory4 ,pr(essor ,newcomb put 8 f+] on ! assumption :i* _h be5 made s long ago t x _h be5 =gott53 & ! lesson is well wor? tak+ to he>t1 = x is n ! fir/ "t t mi/ak5 confid5ce 9 a suppos$ fact has be5 trac$ to "s =gott5 prelim9>y assumption3 & we mu/ be ev] ready to ca/ our eyes backw>d ov] all our assumptions1 :5 "s new fact seems to *all5ge our conclusions4 ,x might fur!r be expect$ t ?is discov]y ( ! way 9 :i* !ory _h be5 defective w\ld z a second>y consequ5ce inspire confid5ce 9 ! o!r conclusions :i* ,mr4 ,*&l] _h arriv$ at 9 app>5t contradiction to !ory2 or at lea/ sugge/ ! susp5sion ( judgm5t4 ,b ,pr(essor ,newcomb did n feel t ?is 0 possible 9 respect ( ! *ange ( p]iod1 f ab\t twelve mon?s 9 ,bradley's "t to f\rte5 mon?s 9 ours4 ,we h se5 t ,mr4 ,*&l] himself reg>d$ ?is z a curi\s result requir+ confirmation3 b s9ce ! confirmation 0 =?com+1 he /at$ x ) full confid5ce1 & drew ! foll[+ rem>ks f ,pr(essor ,newcomb 9 ,july #bb1 #ahib3-- ,! fact ( a p]iodic v>iation ( t]re/rial latitudes1 & ! g5]al law ( t v>iation1 h be5 e/abli%$ beyond reasonable d\bt by ! obs]vations collect$ by ,mr4 ,*&l]4 ,b two ( 8 m9or conclusions1 z enum]at$ 9 ,no4 #c ( ?is volume1 d n seem to me well f\nd$4 ,!y are-- #a4 ,t ! p]iod ( ! inequality is a v>iable quantity4 #b4 ,t ! amplitude ( ! inequality has rema9$ con/ant = ! la/ half c5tury4 ,pr(essor ,newcomb proce$s to give 8 reasons = scepticism1 :i* are too te*nical 9 "* to reproduce "h4 ,b ,i w quote ! foll[+ fur!r s5t5ce f 8 pap]3-- ,! "q n[ arises h[ f> we are entitl$ to assume t ! p]iod mu/ be inv>iable4 ,i reply t1 p]turbations aside1 any v>iation ( ! p]iod is 9 su* direct conflict ) ! laws ( dynamics t we are entitl$ to pron\nce x impossible4 ,b we "k t !re are p]turbations1 & ,i d n see h[ "o c d\bt t !y h s act$ z to increase ! amplitude ( ! v>iation s9ce #ahdj4 ,sid5ote3 ,*&l]'s reply4 ,9 o!r words1 :ile recognis+ t !re may be a way ( reconcil+ "o ( ! m9or conclusions ) !ory1 ,pr(essor ,newcomb consid]s t 9 ?is case ! o!r mu/ g4 ,mr4 ,*&l]'s answ] w speak = itself4 ,x 0 delay$ a little 9 ord] t he might pres5t an imm5se mass ( evid5ce 9 support ( 8 conclusions1 & 0 ultimately pr9t$ on ,augu/ #bc1 #ahib4 ,! mat]ial utilis$ 9 ! =ego+ =ty-five s]ies aggregates m ?an ?irty-?ree ?\s& obs]vations4 ,( ^! m ?an "o-?ird 7 made 9 ! s\!rn hemisph]e1 a fact :i* we owe pr9cipally to ,cordoba4 ,x comprises ! "w ( sev5te5 obs]vatories 7f\r ( !m 9 ! s\!rn hemisph]e7 ) tw5ty-"o diff]5t in/rum5ts1 & by n9e di/9ct me?ods ( obs]vation4 ,only ?ree ( ! s]ies 7,,xxi41 ,,xxv41 & ,,xxxv471 & ^! among ! lea/ precise intr9sically1 give results contradictory ( ! g5]al law develop$ 9 ,no4 #bfg4 ,?is degree ( g5]al h>mony is inde$ surpris+ :5 ! evanesc5t "* ( ! ph5om5on "u inve/igation is consid]$4 ,! read] has n[ be=e him ! means = indep5d5t scrut9y ( ! mat]ial on :i* ! conclusions already drawn1 & ^? :i* are to foll[1 are bas$4 ,! space tak5 9 ! pr9t+ may seem unconscionable1 b ,i hope ?is w be *>g$ to ! ext5t ( ! evid5ce collect$1 & n to diffus5ess or ! pres5tation ( ne$less detail2 = ,i h /udi\sly s\ght to compress ! =m ( /atem5t )\t omitt+ any?+ ess5tial = se>*+ criticism4 ,t x 0 important to d ?is is manife/1 s9ce ! conclusions1 if e/abli%$1 ov]?r[ ! exi/+ !ory ( ! e>?'s rotation1 z ,i h po9t$ out on p4 #ba4 ,i am nei!r surpris$ nor disconc]t$1 !re=e1 t ,pr(essor ,newcomb %\ld hesitate to accept "s ( ^! conclusions on ! gr\nd 7,a4 ,j41 ,no4 #bga7 t !y are 9 su* conflict ) ! laws ( dynamics t we are entitl$ to pron\nce !m impossible4 ,he has be5 s consid]ate & c\rte\s 9 8 treatm5t ( my "w ?us f>1 t ,i am sure he w n deem presumptu\s ! foll[+ argum5t 9 rebuttal4 ,sid5ote3 ,he put aside all tea*+s ( !ory1 & is n dismay$4 ,x %\ld be said1 fir/1 t 9 beg9n+ ^! inve/igations la/ ye>1 ,i delib]ately put aside all tea*+s ( !ory1 because x seem$ to me high "t t ! facts %\ld be exam9$ by a purely inductive process2 t ! nugatory results ( all attempts to detect ! exi/5ce ( ! ,eul]ian p]iod probably arose f a defect ( ! !ory itself2 & t ! entangl$ condition ( ! :ole subject requir$ t x %\ld be exam9$ afre% by processes unfett]$ by any preconceiv$ notions :atev]4 ,! problem :i* ,i !re=e propos$ to myself 0 to see :e!r x w\ld n be possible to lay ! num]\s gho/s--9 ! %ape ( num]\s discordant residual ph5om5a p]ta9+ to det]m9ations ( ab]ration1 p>allaxes1 latitudes1 & ! l--:i* _h h]et(ore flitt$ elusively ab\t ! a/ronomy ( precision dur+ ! c5tury2 or to r$uce !m to tangible =m by "s simple consi/5t hypo!sis4 ,x 0 ?\ght t if ?is c\ld be done1 a /udy ( ! nature ( ! =ces1 z ?us indicat$1 by :i* ! e>?'s rotation is influ5c$1 might lead to a physical explanation ( !m4 ,naturally1 !n1 ,i am n mu* dismay$ by ! argum5t ( conflict ) dynamic laws1 s9ce all t su* a phrase means mu/ ref] m]ely to ! exi/5t /ate ( ! !ory at any giv5 "t4 ,:5 ! #dbg-;day p]iod 0 prop\nd$1 x 0 z inconsi/5t ) kn[n dynamic law z ! v>iation ( x n[ appe>s to be4 ,pr(essor ,newcomb's own happy explanation has already set aside ! fir/ difficulty1 z x w\ld appe>1 & advanc$ ! !ory by an important /ep4 ,are we s sure yet ( a complete k ( all ! =ces at "w z to exclude ! *ance ( a v]a causa = ! second8 ,sid5ote3 ,f>aday's words4 ,!re is a spl5did r+ ( resolution ab\t ^! words4 ,let u comp>e !m ) a notable utt]ance ( ,f>aday3-- ,! philosoph] %\ld be a man will+ to li/5 to e sugge/ion1 b det]m9$ to judge = himself4 ,he %\ld n be biass$ by appe>ances2 h no fav\rite hypo!sis2 be ( no s*ool2 & 9 doctr9e h no ma/]4 ,he %\ld n be a respect] ( p]sons1 b ( ?+s4 ,tru? %\ld be 8 prim>y object4 ,if to ^! qualities be add$ indu/ry1 he may inde$ hope to walk )9 ! veil ( ! temple ( ,nature4 ,sid5ote3 ,*&l]'s o!r "w at ?is "t4 ,sid5ote3 ,8 ultimate satisfactory solution4 ,sid5ote3 ,int]f]5ce ( two waves4 ,te/$ by ?is sev]e /&>d1 ,mr4 ,*&l] fails 9 no p>ticul>1 lea/ ( all 9 t ( indu/ry4 ,! am\nt ( "w he got ?r\gh ab\t ?is "t 0 enorm\s1 = besides ! ma9 l9e ( inve/igation1 ( :i* we h only _h aft] all a m]e glimpse1 he _h be5 able to turn aside to discuss a subsidi>y "q ) ,pr(essor ,com/ock2 he _h exam9$ ) great c>e "s puzzl+ *>act]i/ics 9 ! v>iability ( />s2 he comput$ "s comet ephem]ides2 & he 0 prep>+ a new catalogue ( v>iable />s--a piece ( "w involv+ ! collection & arrangem5t ( great masses ( miscellane\s mat]ial4 ,yet )9 a few mon?s aft] reply+ z above to ,pr(essor ,newcomb's criticism1 he 0 able to ann\nce t he _h f\nd ! key to ! new puzzle1 & t !ory & obs]vation 7 aga9 br\ght into complete accord4 ,we w z be=e li/5 to ! acc\nt ( ?is new /ep 9 8 own words1 b a slight prelim9>y explanation may help ^? unaccu/om$ to ! t]m9ology4 ,! pol> motion 0 f\nd to be comp\nd$ ( two indep5d5t motions1 bo? p]iodic1 b hav+ diff]5t p]iods4 ,n[1 ! g5]al results ( su* a composition are well kn[n 9 sev]al diff]5t bran*es ( physics1 especially 9 ! !ory ( s\nd4 ,if two notes ( ne>ly ! same pit* be /ruck at ! same "t1 we he> ! resultant s\nd alt]nately swell & die away1 because ! vibrations caus$ by ! two notes are sometimes go+ 9 ! same direction1 & aft] an int]val are go+ exactly 9 opposite directions4 ,diagrammatically we %\ld repres5t ! vibrations by two waves1 z bel[2 ! upp] wave goes ?r\gh its p]iod sev5 & a half times betwe5 ,a & ,d1 ! l[] only six times2 & x is easily se5 t at ,a & ,c ! waves are sympa!tic1 at ,b & ,d antipa!tic4 ,at ,a & ,c ! comp\nd vibration w\ld be d\bl$2 at ,b & ,d r$uc$ to ins5sibility4 ,! po9t is s important t p]haps a num]ical illu/ration ( x w n be sup]flu\s4 ,! waves are n[ repres5t$ by r[s ( figures z bel[4 ,! fir/ s]ies recurs aft] e #f1 ! second aft] e #g4 ,illu/ration3 ,,fig4 #h4 ,fir/ ,wave #a #b #c #d #c #b #a #b #c #d #c #b #a #b #c #d #c #b #a #b #c #d #c #b #a #b #c #d #c #b #a ,second ,wave #a #b #c #d #d #c #b #a #b #c #d #d #c #b #a #b #c #d #d #c #b #a #b #c #d #d #c #b #a #b #c ---------------------------------------- --------------------- ,comb9$ ,effect #b #d #f #h #g #e #c #c #e #g #g #f #d #d #d #f #f #f #e #e #e #e #e #e #e #f #f #f #d #d #d ,great di/urbance4 ,calm4 ---------------------------------------- ------------------------------------- ,fir/ ,wave #b #c #d #c #b #a #b #c #d #c #b #a #b #c #d #c #b #a #b #c #d #c #b #a #b #c #d #c #b #a #b ,second ,wave #d #d #c #b #a #b #c #d #d #c #b #a #b #c #d #d #c #b #a #b #c #d #d #c #b #a #b #c #d #d #c ---------------------------------------- --------------------- ,comb9$ ,effect #f #g #g #e #c #c #e #g #h #f #d #b #d #f #h #g #e #c #c #e #g #g #f #d #d #d #f #f #f #e #e ,great di/urbance4 ,sid5ote3 ,illu/ration f ocean travel4 ,add+ ! two r[s toge!r1 ! oscillations at fir/ re9=ce "o ano!r & we get numb]s rang+ f #b to #h in/ead ( f #a to #d2 b "o wave ga9s on ! o!r1 until x is ris+ :5 ! o!r is fall+1 & ! numb]s add up to a /eady s]ies ( #e's4 ,x w be se5 t !re are no less ?an sev5 consecutive #e's1 & all ! v>iation seems to h disappe>$4 ,b pres5tly ! waves sep>ate aga91 & ! p]iod ( great di/urbance recurs2 x w be se5 t 9 ! comb9$ effect ! numb]s repeat exactly aft] ! #dbnd t]m4 ,n[ ^? unfamili> ) ! subject may n be prep>$ = ! addition ( "o physical wave to ano!r1 z ?\gh !y 7 numb]s1 b ! analogy is p]fect4 ,travell]s by "s ( ! fa/ tw9-screw /eam]s h _h unpleasant occasion to notice ?is ph5om5on1 :5 ! eng9e] does n run ! two screws precisely at ! same spe$2 !re come times :5 ! %ip vibrates viol5tly1 sep>at$ by p]iods ( comp>ative /illness4 ,in/ances f o!r walks ( life may recur to ! memory :5 once att5tion is call$ to ! g5]al facts2 b en\gh has be5 said to expla9 ! po9t numb]$ 7#b7 9 ! subjo9$ /atem5t4 ,to und]/& ! re/1 we mu/ rememb] t if ! two waves are n equal 9 amplitude1 i4e4 if ! backw>d & =w>d motion is n ! same 9 bo?1 !y _c annul "o ano!r1 b ! great] w always pr$om9ate4 ,^? int]e/$ 9 foll[+ ! matt] fur!r %\ld h no difficulty 9 con/ruct+ simple examples to illu/rate su* po9ts4 ,we w proce$ to give ,mr4 ,*&l]'s /atem5ts3-- ,sid5ote3 ,*&l]'s f9al =mulae4 ,we n[ come ^u a new l9e ( inve/igation4 ,h]et(ore1 z has be5 se51 ! me?od has be5 to cond5se ! results ( ea* s]ies ( obs]vations into ! int]val compris$ by a s+le p]iod1 !n to det]m9e ! mean epo* ( m9imum & ! mean range = ea* s]ies1 &1 f9ally1 by a discussion ( ^! quantities1 to e/abli% ! g5]al "* ( ! law ( ! rotation ( ! pole4 ,x is n[ requisite to analyse ! obs]vations 9 a diff]5t way1 & discov] :e!r ! deviations f ! g5]al provisional law1 9 ! la/ column ( ,table ,,ii41 are real1 & also 9 :at mann] ! v>iation ( ! p]iod is br\ght ab\t4 ,! outcome ( ?is discussion1 :i* is to be pres5t$ 9 ! pres5t pap]1 is extremely satisfactory4 ,! real nature ( ! ph5om5on is mo/ di/9ctly reveal$1 & may be describ$ z foll[s3-- #a4 ,! obs]v$ v>iation ( ! latitude is ! resultant curve aris+ f two p]iodic fluctuations sup]pos$ ^u ea* o!r4 ,! fir/ ( ^!1 & 9 g5]al ! m consid]able1 has a p]iod ( ab\t #dbg days1 & a semi-amplitude ( ab\t #j4ab4 ,! second has an annual p]iod ) a range v>iable betwe5 #j4jd & #j4bj dur+ ! la/ half-c5tury4 ,dur+ ! middle portion ( ?is int]val1 r\ghly *>act]is$ z betwe5 #ahfj & #ahhj1 ! value repres5t$ by ! l[] limit has prevail$1 b be=e & aft] ^? dates1 ! high] "o4 ,! m9imum & maximum ( ?is annual compon5t ( ! v>iation occur at ! m]idian ( ,gre5wi*1 ab\t t5 days be=e ! v]nal & autumnal equ9oxes respectively1 & x becomes z]o j be=e ! sol/ices4 #b4 ,z ! resultant ( ^! two motions1 ! effective v>iation ( ! latitude is subject to a sy/ematic alt]nation 9 a cycle ( sev5 ye>s' duration1 result+ f ! comm5surability ( ! two t]ms4 ,accord+ z !y conspire or int]f]e1 ! total range v>ies betwe5 two-?irds ( a second z a maximum1 to b a few hundr$?s ( a second1 g5]ally speak+1 z a m9imum4 #c4 ,9 consequ5ce ( ! v>iability ( ! coeffici5t ( ! annual t]m above m5tion$1 ! app>5t av]age p]iod betwe5 #ahdj & #ahee approximat$ to #chj or #cij days2 widely fluctuat$ f #ahee to #ahfe2 f #ahfe to ab\t #ahhe 0 v ne>ly #dbg days1 ) m9or fluctuations2 aft]w>ds increas$ to ne> #ddj days1 & v rec5tly fell to some:at bel[ #djj days4 ,! g5]al c\rse ( ^! fluctuations is q fai?fully repres5t$ by ! law ( eq4 7#c71 7,no4 #bfg71 & accurately1 ev5 d[n to ! m9or oscillations ( individual p]iods1 by ! law ( eq4 7#ae71 h]eaft] giv51 & v]bally int]pret$ above4 ,?is law also gives a simil>ly accurate acc\nt ( ! correspond+ oscillations 9 ! amplitude4 ,! clos5ess ( ! accordance betwe5 obs]vation & ! num]ical !ory1 9 bo? p>ticul>s1 places ! reality ( ! law beyond reasonable d\bt4 ,^? :o _c foll[ ! details ( ! above /atem5t w nev]!less cat* ! g5]al purport--t ! difficulties felt by ,pr(essor ,newcomb h be5 surm\nt$2 & ?is is made cle>] by a lat] extract3-- ,a v important conclusion necess>ily foll[s f ! agreem5t ( ! values ( ! #dbg-;day t]m1 d$uc$ f ! int]vals betwe5 ! consecutive values ( ,t 9 ,table ,,xii41 namely1 t !re has be5 no discont9uity 9 ! revolution1 su* z ,pr(essor ,newcomb reg>d$ z s probable t he d\bt$ ! possibility ( draw+ any conclusions f ! comp>ison ( obs]vations be=e & aft] #ahfj 7,a4 ,j41 #bga1 p4 #ej74 ,sid5ote3 ,!ory mu/ g1 if x w n fit obs]vation4 ,! pres5t inve/igation demon/rates t ! way out ( ! app>5tly irreconcilable contradiction ( !ory & obs]vation 9 ?is matt] does n lie 9 ! direction ( discr$it+ ! obs]vations1 z he is incl9$ to d4 ,on ! contr>y1 ! result is a beautiful v9dication ( ! tru/wor?9ess ( ! latt]1 &1 at ! same "t1 ( ! !ory t dem&s an inv>iable rate ( motion2 provid+ a p]fectly fitt+ key to ! riddle by %[+ t ano!r cause has int]v5$ to produce ! v>iability ( ! p]iod4 ,i feel confid5t t ,pr(essor ,newcomb w agree ) ! reality ( ! explanation "h set =?1 & w reconsid] 8 view t ! p]turbations 9 ! position ( ! ,pole mu/ be ( ! nature ( *ance accumulations ( motion1 a view :i* he !n consid]$ necess>y to ! ma9t5ance ( ! con/ancy 9 ! p]iod ( latitude-v>iation4 ,sid5ote3 ,! f9al pap]4 ,! pap] f :i* ^! words are tak5 appe>$ on ,novemb] #d1 #ahib4 ,! next pap] on ! ma9 !me did n appe> till a ye> lat]1 ?\gh mu* "w 0 be+ done 9 ! meantime on ! con/ant ( ab]ration & o!r matt]s aris+ imm$iately aft] ! discov]y4 ,on ,novemb] #ad1 #ahic1 ,mr4 ,*&l] w9ds up ! s]ies ( eight pap]s ,on ! ,v>iation ( ,latitude1 :i* he _h comm5c$ j two ye>s be=e4 ,8 "w 0 by no means done2 r 0 x only beg9n+1 = ! tor* he _h lit illum9at$ _m d>k corn]s4 ,b he rightly reg>d$ 8 discov]y z n[ s firmly e/abli%$ t ! s]ies ( pap]s deal+ ) x z /ill "u consid]ation might be t]m9at$4 ,9 ?is f9al pap] he fir/ devotes ! mo/ c>eful att5tion to "o po9t ( detail4 ,he _h %[n e>li] 9 ! s]ies t ! ,nor? ,pole mu/ be revolv+ f ,we/ to ,ea/1 & n f ,ea/ to ,we/2 b ?is 0 :5 ! motion 0 suppos$ to be simple & n complex1 & x 0 necess>y to re-exam9e ! "q ( direction = ea* ( ! compon5ts4 ,aft] e/abli%+ conclusively t ! orig9al direction holds = ea* ( ! compon5ts1 he almo/ apologises = ! tr\ble he has tak51 ?us3-- ,x is !re=e prov$ beyond reasonable d\bt t ! directions ( ! rotations is f ,we/ to ,ea/ 9 bo? elem5ts2 :5ce ! g5]al =m ( ! equation = ! v>iation ( latitude adopt$ 9 ,a4 ,j41 #bhd1 p4 #aed1 eq4 7#ai74 ,x may be ?\ght t too mu* pa9s h be5 "h be/[$ ^u a po9t :i* might be tru/$ to !ory to decide4 ,i _c ?9k s4 ,"o ( ! mo/ sali5t results ( ^! articles has be5 ! pro( ( ! fact t !ory has be5 a bl9d guide ) reg>d to ! velocity ( ! ,pol> rotation1 obscur+ tru? & mislead+ inve/igators = a half a c5tury4 ,& ev5 if we 7 c]ta91 :i* we are n1 t ! f\rte5 mon?s' t]m is ! ,eul]ian p]iod 9 a modifi$ =m4 ,x w\ld /ill be necess>y to settle by obs]vation ! direction ( ! annual motion1 ) reg>d to :i* !ory is p[]less to in=m u4 ,to save repetition ( argum5t1 ,i mu/ ref] to ! /atem5t 9 ,a4 ,j41 #bgc1 pp4 #fh1 #gj1 ( ! pr9ciples adopt$ 9 beg9n+ ^! inquiries 9 #ahia4 ,f9ally1 he answ]s "o ( ! few objectors ( em95ce :o /ill l+]$1 ! great ,fr5* physici/ ,cornu3-- ,sid5ote3 ,cornu answ]$4 ,! gr\nd is n[ cle>$ = exam9ation ( ! only topic rema9+ to be cov]$1 to e/abli%1 ^u ! f\ndation ( fact1 e po9t 9 ! pres5t !ory ( ^! rem>kable movem5ts ( ! e>?'s axis4 ,?is is ! "q ( ! possibility t ^! movem5ts are n real1 b m]ely mis9t]pretations ( ! obs]v$ ph5om5a2 be+ 9 :ole or 9 "p an illusory effect ( in/rum5tal error due to ! influ5ce ( temp]ature4 ,su* a possibility has be5 a nightm>e 9 practical a/ronomy f ! fir/1 fright5+ u 9 e s]ies ( unexpla9$ residuals1 br\ght to light cont9ually 9 ne>ly all attempts at delicate in/rum5tal rese>*4 ,a s\rce ( dang] s subtile c\ld n fail to be ev] pres5t 9 ! m9d ( e a/ronom] & physici/ :o has giv5 ev5 a sup]ficial att5tion to ! "q ( ! latitude v>iations1 & !re is no d\bt t "s are ev5 n[ ?us det]r$ f accept+ ^! v>iations z prov$ facts4 ,p]haps ! mo/ explicit & =cible /atem5t ( ! d\bts t may arise on ?is subject has be5 giv5 v rec5tly by ,mr4 ,cornu4 ,! views ( s di/+ui%$ a physici/1 & ( o!rs :o are incl9$ to agree ) him1 call = c>eful att5tion1 & _c be neglect$ 9 ! pres5t clos+ argum5t ^u ! !ory pres5t$ 9 ^! articles4 ,x is unnecess>y1 = ! purpose ( dispos+ ( objections ( ! sort rais$ by ,cornu1 to insi/ t x is n suffici5t to %[ t ! obs]v$ v>iations1 attribut$ to ! un/ead9ess ( ! ,e>?'s ,pole1 are ne> ! limit ( precision atta9able 9 l9e> diff]5tial measures1 & 9 ! indication ( ! direction ( gravity by means ( ! air bubble ( ! level2 or to %[ t !re are kn[n v>iations 9 divid$ circles & 9 levels1 dep5d5t on temp]ature & seasons4 ,nor ne$ we require ( objectors ! difficult1 al?\gh ess5tial1 task--:i* !y h n di/9ctly attempt$--( %[+ t ^! errors are n elim9at$1 z !y appe> to be1 by ! modes 9 :i* a/ronom]s use _! in/rum5ts4 ,nei!r ne$ we ev5 urge ! fact t a l>ge portion ( ! data :i* h be5 utilis$ 9 ! pres5t rese>*es on ! latitude 7 d]iv$ by me?ods :i* disp5se ) levels1 or ) circles1 a "p ( !m inde$ ) bo?1 & yet t ! results ( all are h>moni\s4 ,on ! contr>y1 let u admit1 al?\gh m]ely = argum5t's sake1 t all ! kn[n means ( det]m9+ ! direction ( gravity--includ+ ! plumb-l9e1 ! level1 & a fluid at re/1 :e!r us$ = a reflect+ surface or z a support = a float+ in/rum5t--are subject to a common law ( p]iodical error :i* vitiates ! result ( a/ronomical obs]vation1 obta9$ by :atev] me?ods1 & 9 precisely ! same mann]4 ,n[1 ! obs]v$ law ( latitude v>iation includes two t]ms1 ) p]iods ( f\rte5 & twelve mon?s respectively4 ,s9ce ! phases ( ! fir/ t]m are repeat$ at int]vals ( two mon?s 9 successive ye>s1 & h5ce 9 a s]ies ( ye>s come into all possible relations to conditions ( temp]ature dep5d5t on season1 ! argum5t aga9/ ! reality ( ?is t]m1 on ?is gr\nd1 absolutely fails1 & ne$s no fur!r notice4 ,z to ! second1 or annual t]m1 :ile ! phases1 z obs]v$ 9 any giv5 longitude1 are inde$ syn*ronical ) ! seasons1 !y are n s z reg>ds diff]5t longitudes4 ,if1 !re=e1 ! times ( any giv5 phase1 z obs]v$ 9 ! same latitude1 b 9 successively increas+ longitudes1 occurr$ at ! same date 9 all ( !m1 !re w\ld be a fatal presumption aga9/ ! exi/5ce ( an annual p]iod 9 ! pol> motion4 ,if1 on ! contr>y1 !y occur at times successively correspond+ to ! diff]5ces ( longitude1 ! presumption is equally fatal to ! hypo!sis t !y c possibly be due to temp]ature v>iation z affect+ in/rum5tal measurem5t4 ,b ! facts giv5 9 ! =ego+ section correspond mo/ di/9ctly to ! latt] condition4 ,!re=e1 unless additional facts c be br\ght to disprove successively ^! obs]v$ results1 we may dismiss = ev] ! bugbe> :i* has und\bt$ly l$ _m to di/ru/ ! reality ( ! annual compon5t ( ! latitude-v>iation1 :ile !y admit ! exi/5ce ( ! #dbg-;day t]m4 ,sid5ote3 ,consequ5ces ( ! discov]y4 ,sid5ote3 ,suspect$ obs]v]s acquitt$4 ,at ?is po9t we mu/ leave ! fasc9at+ acc\nt ( ! mann] 9 :i* ?is great discov]y 0 e/abli%$1 9 ! tee? ( opposition su* z might h dismay$ & dissuad$ a less cle>-sight$ or c\rage\s man4 ,x is my purpose to lay m /ress ^u ! me?od ( mak+ ! discov]y ?an ^u its results2 b we may af=d a brief glance at "s ( ! consequ5ces :i* h already begun to fl[ f ?is /ep 9 advance4 ,"s ( !m h inde$ already come be=e u1 especially t l>ge class repres5t$ by ! explanation ( anomalies 9 s]ies ( obs]vations :i* _h be5 put aside z inexplicable4 ,we h se5 h[ ! obs]vations made 9 ,russia1 or 9 ,wa%+ton1 or at ,gre5wi*1 9 all ( :i* !re 0 "s puzzl+ error1 7 imm$iately /raight5$ out :5 ,*&l] appli$ 8 new rule to !m4 ,we 9 ,engl& h special cause to be grateful to ,*&l]2 n only has he demon/rat$ m cle>ly ?an ev] ! greatness ( ,bradley1 b he has rehabilitat$ ,pond1 ! ,a/ronom] ,royal ( ! beg9n+ ( ! n9ete5? c5tury2 %[+ t 8 obs]vations1 :i* _h be5 condemn$ z 9 "s way errone\s1 7 really f> m accurate ?an might h be5 expect$2 & fur!r he has %[n t ! beautiful in/rum5t design$ by ,airy1 & call$ ! ,reflex ,z5i? ,tube1 :i* seem$ to h unacc\ntably fail$ 9 ! purpose = :i* x 0 design$1 0 really all ! "t accumulat+ obs]vations ( ?is new ph5om5on1 ! ,v>iation ( ,latitude4 ,in/ead ( ,airy hav+ fail$ 9 8 design1 he _h 9 ,*&l]'s words build$ bett] ?an he knew4 ,sid5ote3 ,con/ant ( ,ab]ration improv$4 ,secondly1 !re is ! modify+ influ5ce ( ?is new ph5om5on on o!r ph5om5a already kn[n1 su*1 = in/ance1 z t ( ab]ration4 ,we saw 9 ! ?ird *apt] h[ ,bradley discov]$ ?is effect ( ! velocity ( light1 & h[ ! measure ( x is obta9$ by comp>+ ! velocity ( light ) t ( ! e>?4 ,?is comp>ison c be effect$ 9 a v>iety ( ways1 & we %\ld expect all ! results to agree )9 c]ta9 limits2 b ?is agreem5t 0 n obta9$1 & ,*&l] has be5 able to %[ "o reason :y1 & to remove "s ( ! m tr\blesome diff]5ces4 ,x is impossible to give "h an idea ( ! f>-rea*+ consequ5ces :i* su* "w z ?is may h2 s long z !re are diff]5ces ( ?is k9d we _c tru/ any "p ( ! *a9 ( evid5ce1 & !re is 9 prospect ! enorm\s lab\r ( exam9+ ea* sep>ate l9k until ! error is f\nd4 ,! velocity ( light1 = in/ance1 may be measur$ by a t]re/rial exp]im5t2 0 !re any?+ wrong 9 ! app>atus8 ,! velocity ( ! e>? 9 its j\rney r\nd ! sun dep5ds directly ^u ! di/ance ( ! sun3 h we measur$ ?is di/ance wrongly1 & if s :at 0 ! error 9 ! obs]vations made8 ,^! are "s ( ! que/ions :i* may arise s long z ! values = ! ,con/ant ( ,ab]ration are /ill conflict+2 b x requires consid]able k ( a/ronomy to appreciate !m fully4 ,sid5ote3 ,latitude ,v>iation ,tide4 ,sid5ote3 ,e>?quakes4 ,ano!r example w1 p]haps1 be ( m g5]al int]e/4 ,if ! axis ( ! e>? is execut+ small oscillations ( ?is k9d1 !re %\ld be an effect ^u ! tides2 ! liquid ocean %\ld feel ! wobble ( ! e>?'s axis 9 "s way2 & an exam9ation ( tidal regi/]s %[$ t !re 0 9 fact a di/9ct effect4 ,x may cause "s amusem5t :5 ,i say t ! rise & fall are only a few in*es 9 any case2 b !y are unmi/akable evid5ces t ! e>? is n sp9n+ smoo?ly1 b has ?is k9d ( unbalanc$ vibration1 :i* ,i h comp>$ to ! vibrations felt by pass5g]s on an imp]fectly eng9e]$ tw9-screw /eam]4 ,a m s5sational effect is t app>5tly e>?quakes are m num]\s at ! "t :5 ! vibration is greate/4 ,we rem>k$ t ! vibration waxes & wanes1 mu* z t ( ! /eam] waxes & wanes if ! tw9-screws are n runn+ q toge!r4 ,n[ ! pass5g]s on ! /eam] w\ld be prep>$ to f9d t breakages w\ld be m num]\s dur+ ! times ( vigor\s oscillation2 & x seems probable t 9 a simil> way ! little cracks ( ! e>?'s sk9 :i* we call great e>?quakes are m num]\s :5 ^! unbalanc$ vibrations are at _! maximum2 t is to say1 ab\t once e sev5 ye>s4 ,?is result is sc>cely yet wor?y ( complete confid5ce1 = our obs]vations ( e>?quakes h only v rec5tly be5 r$uc$ to prop] ord]2 b if x %\ld turn out to be true1 x is sc>cely necess>y to add any words ( m9e to demon/rate ! importance ( ?is r unexpect$ result ( ! ,latitude ,v>iation4 ,sid5ote3 ,! ,kimura ph5om5on4 ,f9ally ,i w m5tion ano!r ph5om5on :i* seems to be at pres5t m ( a curiosity ?an any?+ else1 b :i* may lead to "s future great discov]y4 ,x is ! outcome ( obs]vations :i* h be5 rec5tly made to wat* ^! motions ( ! ,pole2 = al?\gh !re seems good reason to accept ,mr4 ,*&l]'s laws ( v>iation z accurate1 x is necess>y to e/abli% _! accuracy & complete ! details by mak+ obs]vations = "s "t yet to come2 & !re c\ld be no bett] pro( ( ?is necessity ?an ! discov]y rec5tly made by ,mr4 ,kimura1 "o ( ^? engag$ 9 ?is wat* ( ! ,pole 9 ,japan4 ,p]haps ,i c give ! be/ idea ( x by m5tion+ "o possible explanation1 :i*1 h[ev]1 ,i mu/ caution y may n be by any means ! "r "o4 ,we are accu/om$ to ?9k ( ?is great e>? z be+ suffici5tly con/ant 9 %ape2 if ask$1 = in/ance1 :e!r its c5tre ( gravity rema9s con/antly 9 ! same place inside x1 we %\ld almo/ c]ta9ly answ] 9 ! affirmative1 j z only tw5ty ye>s ago we ?\ght t ! ,nor? ,pole rema9$ 9 ! same place4 ,b x seems possible t ! c5tre ( gravity moves a few feet backw>ds & =w>ds ea* ye>--?is w\ld at any rate expla9 c]ta9 curi\s features 9 ! obs]vations to :i* ,mr4 ,kimura has drawn att5tion4 ,:atev] ! explanation ( !m may be1 or to settle :e!r ?is explanation is correct1 we want m obs]vations1 especially obs]vations 9 ! ,s\!rn ,hemisph]e2 & x is a project "u consid]ation by a/ronom]s at ! pres5t mom5t :e!r ?ree /ations c be e/abli%$ 9 ! ,s\!rn ,hemisph]e = ! fur!r obs]vation ( ?is curi\s ph5om5on4 ,! "q resolves itself *iefly into a "q ( money2 inde$1 mo/ a/ronomical projects d ultimately resolve !mselves into que/ions ( money2 & ,i fe> ! _w looks ^u sci5tific m5 z insatiable 9 ?is respect4 ,"o c only hope t on ! :ole ! money is exp5d$ s z to give a satisfactory return4 ,9 ?is in/ance ,i h no hesitation 9 say+ t an imm$iate return ( value = a comp>atively mode/ exp5diture is practically c]ta91 if only 9 "s way we c get ! means ( mak+ ! obs]vations4 ,x w\ld be natural1 at ! conclusion ( ?is brief review ( "s types ( a/ronomical discov]y1 to summ>ise ! lessons indicat$3 b !re is ! important difficulty t !re appe> to be none4 ,x has be5 po9t$ out z we proce$$ t :at seem$ to be a safe d$uction f "o piece ( hi/ory has be5 flatly contradict$ by ano!r2 no soon] h we le>nt t important results may be obta9$ by pursu+ /eadily a l9e ( "w 9 spite ( ! fact t x seems to h become t$i\s & unpr(itable 7z 9 ! se>* = m9or planets7 ?an we are confront$ ) ! possibility t by su* simple devotion to ! day's "w we may be los+ a great opportunity1 z ,*allis did4 ,we c sc>cely g wrong 9 foll[+ up ! /udy ( residual ph5om5a 9 ! wake ( ,bradley2 b !re is ! important difficulty t we may be :olly unable to f9d a clue = ! arrangem5t ( our residuals1 z is at pres5t l>gely ! case 9 meteorology4 ,&1 9 g5]al1 human expectations are likely to be q mislead+1 z has be5 %[n 9 ! la/ two *apt]s2 ! discov]ies we desire may lie 9 ! direction precisely opposite to t indicat$ by ! be/ op9ion at pres5t available4 ,!re is no royal road to discov]y1 & ?\gh ?is /atem5t may meet ) su* ready acceptance t x seems sc>cely wor? mak+1 x is hop$ t !re may be suffici5t ( int]e/ 9 ! illu/rations ( its tru?4 ,! "o positive conclusion :i* we may d]ive f ! examples /udi$ is t discov]ies are seldom made )\t bo? h>d "w & conspicu\s ability4 ,a new planet1 ev5 z l>ge z ,uranus1 does n reveal itself to a passive obs]v]3 ?irte5 times x may appe> to su* a "o )\t fe> ( detection1 until at la/ x enc\nt]s an al]t ,h]s*el1 :o suspects1 te/s1 & v]ifies1 & ev5 !n ann\nces a comet--s little did he realise ! :ole tru?4 ,fifte5 ye>s ( unrequit$ lab\r be=e ,a/raea 0 f\nd1 n9ete5 ye>s ( obs]vation be=e ! discov]y ( nutation c\ld be ann\nc$3 h[ seldom d ^! ye>s ( toil pres5t !mselves to our imag9ations :5 we glibly say t ,bradley discov]$ nutation1 or ,h5cke discov]$ ,a/raea6 ,t ! necess>y lab\r is s (t5 =gott5 mu/ be my excuse = recall+ att5tion to x some:at p]si/5tly 9 ^! examples4 ,b beyond ! fact t he mu/ "w h>d1 x w\ld seem z ?\gh !re 7 little ( value to tell ! w\ld-be discov]]4 ,! situation has be5 well summ>is$ by ,jevons 9 8 *apt] on ,induction 9 ! ,pr9ciples ( ,sci5ce2 & 8 words w =m a fitt+ conclusion to ^! *apt]s3-- ,x w\ld seem z if ! m9d ( ! great discov]] mu/ comb9e contradictory attributes4 ,he mu/ be f]tile 9 !ories & hypo!ses1 & yet full ( facts & precise results ( exp]i5ce4 ,he mu/ ent]ta9 ! feeble/ analogies1 & ! m]e/ guesses at tru?1 & yet he mu/ hold !m z wor?less till !y are v]ifi$ 9 exp]im5t4 ,:5 !re are any gr\nds ( probability he mu/ hold t5aci\sly to an old op9ion1 & yet he mu/ be prep>$ at any mom5t to rel9qui% x :5 a cle>ly contradictory fact is enc\nt]$4 ,,index ,ab]ration1 #aje-aji1 #aaa1 #aab1 #aag1 #aah1 #ahe1 #ahh1 #aib1 #bad1 #bae ,accid5tal discov]y1 #ae1 #gc1 #aba-aed ,adams1 #ab1 #de-he2 resolution1 #ee ,airy1 #cb1 #dj-he1 #bad ,algi]s1 #acj ,allegh5ia1 #bf ,almucant>1 #ahj1 #aha ,alphabet us$ = planets1 #bg ,&]son1 ,dr4 ,t4 ,c41 #h1 #adb1 #adc1 #add1 #adf ,an!lm1 #adb ,apollo1 #i ,argon1 #aji ,asc5sion1 #cd ,assumption1 =gott51 #aif ,a/raea1 #bb1 #bc1 #bai ,a/rographic *>t1 #abb1 #abe1 #acj ,a/ronomical ,j\rnal1 #agg-bag ,a/ronomis*e ,na*ri*t51 #eb1 #aeh ,a/rophil1 #adc ,auw]s1 #adb ,ball1 ,sir ,r41 #bd ,balliol ,college1 #hg ,banks1 ,sir ,j41 #i ,b>n>d1 ,e4 ,e41 #adf1 #bbj ,b]l91 #aha1 #ahc1 #ahd1 #ahh1 #aic ,b]l9 />-map1 #de1 #ff1 #hc1 #abd ,bessel1 #aib ,bett9a1 #bf1 #bg ,birm+ham1 #adb ,black ,drop 79 transit ( ,v5us71 #cj ,bliss1 #aad ,bo>d ( ,visitors ( ,gre5wi* ,obs]vatory1 #fc ,bode1 #aa1 #ad1 #ae1 #bb ,bode's ,law1 #ab1 #ac1 #ch1 #dc1 #de1 #eb1 #gb1 #gf1 #gg1 #hd ,b\rdeaux1 #acj ,b\v>d1 #ci1 #dj1 #db1 #dh1 #di1 #ej1 #fa ,bradley1 #ci1 #hf-abj1 #ahh-aib1 #bac1 #bad1 #bah1 #bai ,bradley1 ,john1 #aae ,brem51 #bj ,brid/[1 #hg1 #hh1 #id ,briggs1 #aai ,br9kley1 #aib ,briti% ,association1 #fc ,bru5n[1 #aic ,cali=nia1 #bf ,cambridge 7,mass471 #ahj1 #ahd1 #ahh ,cambridge ,obs]vatory1 #bc1 #db1 #di1 #eb1 #fc1 #fe1 #ff1 #ace1 #aic ,cambridge ,univ]sity1 #fh-ga1 #aad ,cape ,obs]vatory1 #abc1 #abd1 #acj ,c>ds1 #aa ,cass9i ,,ii41 #aef ,catania1 #acj ,c]es1 #ad-bb ,*acornac1 #abd ,*allis1 #di-ed1 #fc-fh1 #ga1 #he1 #bah ,*&l]1 ,s4 ,c41 #aah1 #agg-bag ,*apman's ,hom]1 #b ,*icago1 #aeg ,*romosph]e1 #agj ,cl>ke1 ,c4 ,c41 #b ,coelo/at1 #id ,columbus1 #fc ,comet1 #d-h1 #hh1 #ajh1 #aag1 #abc1 #abe ,commission1 planet>y1 #bg ,common1 ,a4 ,a41 #abd1 #abg ,compte ,r5du1 #fb ,com/ock1 #bjb ,conf]5ce1 ,a/rographic1 #abe-acf ,cop]nicus1 #gi1 #ie ,cordoba1 #acj1 #aii ,cornu1 #baj-bac ,corona1 #agj-age ,cosmos 7,humboldt's71 #afj ,delambre1 #aeg ,deviation ( ,pole1 #ahg ,disc ( ,neptune1 #dd1 #fd1 #gi ,disc ( ,uranus1 #d-g ,dorpat1 #aib ,d\blet 7photographic71 #abg-abi ,draconis1 gamma1 #if-ajd ,draconis1 beta1 #aic ,driess51 #bc ,dry plate1 #abb ,dubl91 #aib ,e>?quakes1 #bae ,e>?'s ,pole1 #agg-bag ,ecc5tricity1 #da1 #hc ,eclipses1 #agj-agf ,ed9burgh1 #adc ,edu>da1 #bf ,eg]ia1 #bb ,endymion1 #be ,eriphyla1 #bf ,eros1 #be1 #bf1 #bh1 #ce1 #cg1 #fh ,eul]ian1 #bjj1 #bji ,evelyn1 #bf ,exposure1 times (1 #abb1 #aca ,faculae1 #agj ,f>aday1 #bja ,flam/e$1 #ci1 #ec1 #aae ,flem+1 ,mrs41 #adb ,flora1 #bb ,f\lkes1 ,m>t91 #id ,fr5* ,academy1 #dc1 #ea1 #fb ,galileo1 #ie1 #afc ,galle1 #dd1 #de1 #dg1 #ff1 #fg1 #hc ,gasp>is1 #bb ,gauge 7railways71 #ef ,gauss1 #ag-bj ,gem9orum1 ,h41 #d ,george ,,iii41 #h1 #aj ,georgian1 #aa ,georgium ,sidus1 #h1 #aj1 #aa ,gill1 ,sir ,d41 #cb1 #cd1 #ce1 #abc ,gilliss1 #cb ,go?a1 #bj ,g\ld1 #cb ,graham1 #bb1 #bc ,gravitation1 law (1 #ch1 #de1 #ei1 #hd1 #aje ,greaves1 #aai ,gre5wi* ,obs]vatory1 #dh-fd1 #hh1 #hi1 #aad-aag1 #acj1 #afj-afi1 #ahb1 #aib1 #aic1 #bjf1 #bac ,gregory1 #ic1 #aai ,hale1 ,g4 ,e41 #agj1 #aga ,hall1 ,a41 #ahd1 #ahe ,halley1 #hh-ib1 #ajh1 #aab-aaf1 #aai ,hans51 #da1 #ei ,h>kness1 #ahd ,h>twig1 #adb ,h>v>d ,college ,obs]vatory1 #abh1 #adb1 #add1 #ade ,hebe1 #bb ,hegel1 #ae ,heidelb]g1 #ade ,heliomet]1 #cb1 #cd ,helium1 #aji ,hels+=s1 #acj ,h5cke1 #bb1 #bc1 #fd1 #aec1 #bai ,h5ry bro!rs1 #abd-abi ,h]s*el1 ,sir ,john1 #fc1 #ge1 #hc ,h]s*el1 ,sir ,william1 #b-aa1 #ci1 #dd1 #hb1 #bai ,h]s*el 7,uranus71 #aa1 #ab ,h9d1 #bb1 #bc1 #be1 #adb ,hooke1 #if1 #ig ,hubb>d1 #ahd ,humboldt1 #afj ,hussey1 ,rev4 ,t4 ,j41 #dj1 #db ,hygeia1 #bb ,ilmata1 #bf ,indu/ria1 #bf ,+eborg1 #bf ,in/rum5ts at ,gre5wi*1 #aad-aaf ,iris1 #bb1 #bc1 #cb1 #ce ,janson1 #adb ,jevons1 #bai ,johnson1 ,m41 #aef1 #afj ,juno1 #i1 #ba1 #bb ,jupit]1 #i1 #bh1 #dc1 #di1 #ej1 #fa2 satellites1 #ib1 #aag ,keats1 #a-c1 #g1 #h ,keill1 #id1 #aab1 #aai1 #aef ,kelv91 ,"l1 #aif1 #aig ,kepl]1 #ie1 #adb ,kew1 #ie1 #if1 #ahh1 #aij ,kiel1 #ada ,kimura1 #baf ,ko5igsb]g1 #aib ,kue/n]1 #aah1 #aha1 #ahc ,lal&e1 #g1 #aa1 #ajg1 #aeg ,lameia1 #bf ,laplace1 #fa ,la ,plata1 #acj ,latitude v>iation1 #ii1 #ajj1 #aag1 #aah1 #agg-bag ,lemonni]1 #ci1 #ec1 #aeg ,le ,v]ri]1 #ab1 #dc-he ,libussa1 #bf ,lick ,obs]vatory1 #aeb ,li\ville's ,j\rnal1 #gc ,lisbon1 longitude (1 #ib ,london1 #bc1 #be1 #if ,long1 #aeg ,longitude1 #ib1 #aag ,l[?1 ,bi%op1 #aai ,lyrae1 alpha1 #ahd1 #aif ,macclesfield1 ,e>l (1 #id1 #aac ,ma$l]1 #aib ,magnetic obs]vations1 #afa1 #afd1 #agd ,magnitude equation1 #ace ,m>kree1 #bc ,m>s1 #i1 #bh1 #cb1 #cd1 #ce1 #ia ,may]1 #ci ,measurem5t ( plates1 #acb-ace ,mecanique ,cele/e1 #fa ,melb\rne1 #acj1 #aic ,memor&um 7,adams71 #ee ,m]cury1 #i ,messi]1 #g ,meteorites1 #ei ,meteors 7,novemb]71 #fj ,metis1 #bb1 #bc ,micromet]1 #e1 #acc ,milky ,way1 #abe ,m9]va1 #i ,m9or planets1 #ac-bh ,m9or planets tables1 #bb1 #bd1 #bf ,mi/akes1 #ga-hc ,molyneux1 ,samuel1 #id-if1 #aja1 #ajd ,monte ,video1 #acj ,moon1 tables (1 #aag ,names ( m9or planets1 #bb-bh ,nasmy?1 #afb ,nautical ,almanac1 #aa ,nebula1 #abd1 #adf-aeb ,neptune1 #aa1 #ab1 #ch-he1 #abd ,new ,college ,lane1 #aab ,newcomb1 ,simon1 #ha1 #ahc1 #ahd1 #aie-bjb1 #bjg1 #bjh ,new />s1 #aba1 #adj-aed ,newton1 #ch1 #hd1 #ij-ie1 #aje1 #aac ,new ,york1 longitude1 #ib ,n99a1 #bf ,nor?lea*1 #hg ,nor?umb]l&1 #fe ,nova ,gem9orum1 #ada1 #ade1 #adf ,nova ,p]sei1 #adc1 #adf-aeb ,nutation1 #ii1 #ajj1 #aaj1 #aae1 #aag1 #aah1 #ahh1 #bai ,obs]vatory 7magaz9e71 #bf ,ocllo1 #bf ,olb]s1 #bj-bb ,olympic games1 #aai ,oriani1 #ae ,ornam5ta1 #bf ,ox=d ,univ]sity1 #hg-hi1 #id1 #aje-aai ,ox=d ,univ]sity ,obs]vatory1 #aba1 #acj1 #acb1 #acf1 #adb1 #ade1 #aed ,pal]mo1 ,obs]vatory (1 #ah ,palisa1 #bf ,pallas1 #i1 #ba1 #bb ,p>allax1 #cd1 #ia1 #ie-ih1 #aji1 #ahe ,p>is1 #acj ,p>khur/1 ,j4 ,a41 #ade ,p>!nope1 #bb ,peirce1 #gc1 #hj-hc ,p5dulum1 #aag ,p]seus1 #h1 #adc ,p]sonal equation1 #ca1 #acd1 #ace1 #ahe ,p]?1 #acj ,p]turbations ( ,uranus1 #ab1 #db1 #ea1 #ed1 #ee1 #fa1 #ge ,pet]s1 #ahh1 #aib ,phaetusa1 #bf ,philosoph]1 #bja1 #bai ,philosophical ,transactions1 #c1 #d1 #i ,photographica1 #bf ,photographic me?ods1 #bd1 #cc1 #cf1 #aba-aci2 l5ses1 #abe1 #abf ,photographs ( sun1 #afc1 #agj-agc ,piazzi1 #ac-ah1 #bb ,pick]+1 ,e4 ,c41 #abh1 #add ,pittsburghia1 #bf ,plana1 #fa ,planet>y di/ances1 #ac2 commission1 #bg2 numb]+1 #bg ,planets by photography1 #bd ,pole ,/> 7,pol>is71 #agg1 #agh1 #aib1 #aic ,pond1 #aib1 #bac ,potsdam1 #acj1 #aha ,p\nd1 ,mrs41 #ajd1 #aaj-aab ,p\nd1 ,rev4 ,james1 #hi-id1 #ajd1 #aae ,prague1 #aha ,precession1 #if1 #agh ,prymno1 #bf ,puiseux1 #cb ,pulfri*1 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