,,transcrib]',s ,,note ,italic text is d5ot$ by und]scores4 ,obvi\s typographical errors & punctuation errors h be5 correct$ aft] c>eful comp>ison ) o!r occurr5ces )9 ! text & consultation ( ext]nal s\rces4 ,m detail c be f\nd at ! end ( ! book4 ,,practical ,,talks ,,by ,,an ,,a/ronom] ,illu/ration3 ,! ,moon4 ,fir/ ,qu>t]4 ,photograph$ by ,loewy & ,puiseux1 ,febru>y #ac1 #ahid4 ,,practical ,,talks ,,by ,,an ,,a/ronom] ,,by ,,h>old ,,jacoby ,,adjunct ,,pr(essor ,,( ,,a/ronomy ,,9 ,,columbia ,,univ]sity ,,illu/rat$ ,,new ,,york ,,*>les ,,scribn]',s ,,sons #aijb ,,copyright1 #aijb1 ,,by ,,*>les ,,scribn]',s ,,sons ,publi%$1 ,april1 #aijb ,,tr[ ,,directory ,,pr9t+ ,,& ,,bookb9d+ ,,company ,,new ,,york ,,preface ,! pres5t volume has n be5 design$ z a sy/ematic treatise on a/ronomy4 ,!re are _m excell5t books ( t k9d1 suitable = s]i\s /ud5ts z well z ! g5]al read]2 b !y are necess>ily some:at dry & unattractive1 because !y mu/ aim at complet5ess4 ,complet5ess means detail1 & detail means dryness4 ,b ! sci5ce ( a/ronomy conta9s subjects t admit ( deta*$ treatm5t2 & z _m ( ^! are precisely ! ones ( greate/ g5]al int]e/1 x has seem$ well to select sev]al1 & describe !m 9 language free f te*nicalities4 ,x is hop$ t ! book w ?us prove useful to p]sons :o d n wi% to give ! "t requir$ = a /udy ( a/ronomy z a :ole1 b :o may take pleasure 9 devot+ a half-h\r n[ & !n to a deta*$ essay on "s special topic4 ,prep>ation ( ! book 9 ?is =m has made x suitable = prior publication 9 p]iodicals2 & ! sev]al essays h 9 fact all be5 pr9t$ be=e4 ,b ! int5tion ( collect+ !m into a book 0 kept 9 m9d f ! fir/2 & :ile no attempt has be5 made at consecutiv5ess1 x is hop$ t no?+ ( m]ely ephem]al value has be5 includ$4 ,,cont5ts ,,page ,,navigation ,,at ,,sea #a ,,! ,,pleiades #aj ,,! ,,pole-,,/> #ah ,,nebul #bg ,,tempor>y ,,/>s #cg ,,galileo #dg ,,! ,,planet ,,( #ahih #eh ,,h[ ,,to ,,make ,a ,,sun-,,dial #fi ,,photography ,,9 ,,a/ronomy #ha ,,"t ,,/&>ds ,,( ,,! ,,_w #aaa ,,motions ,,( ,,! ,,e>?',s ,,pole #aca ,,saturn',s ,,r+s #adj ,,! ,,heliomet] #aeb ,,occultations #afa ,,m\nt+ ,,great ,,telescopes #agj ,,! ,,a/ronom]',s ,,pole #ahd ,,! ,,moon ,,hoax #aii ,,! ,,sun',s ,,de/9ation #baj ,,illu/rations ,,! ,,moon4 ,,fir/ ,,qu>t] ,frontispiece ,photograph$ by ,loewy & ,puiseux1 ,febru>y #ac1 #ahid4 ,,fac+ ,,page ,,spiral ,,nebula ,,9 ,,con/ellation ,,leo #bf ,photograph$ by ,keel]1 ,febru>y #bd1 #aijj4 ,,nebula ,,9 ,,&rom$a #bh ,photograph$ by ,b>n>d1 ,novemb] #ba1 #ahib4 ,,! ,,dumb-,,bell ,,nebula #cd ,photograph$ by ,keel]1 ,july #ca1 #ahii4 ,,/>-,,field ,,9 ,,con/ellation ,,monoc]os #hd ,photograph$ by ,b>n>d1 ,febru>y #a1 #ahid4 ,,sol> ,,corona4 ,,total ,,eclipse #ajh ,photograph$ by ,campbell1 ,janu>y #bb1 #ahih2 ,jeur1 ,india4 ,,=ty-,,in* ,,telescope1 ,,y]kes ,,obs]vatory #agj ,,y]kes ,,obs]vatory1 ,,univ]sity ,,( ,,*icago #agf ,,practical ,,talks ,,by ,,an ,,a/ronom] ,,navigation ,,at ,,sea ,a %ort "t ago ! writ] _h occasion to rummage among ! ar*ives ( ! ,royal ,a/ronomical ,society 9 ,london1 to consult1 if possible1 ! orig9al manuscripts left by "o ,/eph5 ,groombridge1 an ,engli% a/ronom] ( ! good old days1 :o di$ 9 #ahcb4 ,x 0 kn[n t !y _h be5 fil$ away ab\t a g5]ation ago1 by ! late ,sir ,george ,airy1 :o 0 ,a/ronom] ,royal ( ,engl& betwe5 ! ye>s #ahce & #ahha4 ,aft] a long se>*1 a l>ge & du/y box 0 f\nd & op5$4 ,x 0 fill$ ) docum5ts1 ( :i* ! topmo/ 0 9 ,sir ,george's own h&writ+1 & began sub/antially z foll[s3 ,li/ ( articles )9 ?is box4 ,no4 #a1 ,?is li/1 ,no4 #b1 etc41 etc4 ,a/ronomical precision c no fur!r g3 he _h li/$ ev5 ! li/ itself4 ,truly1 ,airy 0 rightly /yl$ pr9ce ( precisians4 ,a wor?y ,a/ronom] ,royal 0 he1 to act "u ! royal w>rant ( ,*>les ,,ii41 :o e/abli%$ ! (fice 9 #afge4 ,d[n to ?is pres5t day t w>rant /ill makes x ! duty ( ,8 ,maje/y's ,a/ronom] to apply himself ) ! mo/ exact c>e & dilig5ce to ! rectify+ ( ! tables ( ! motions ( ! heav5s & ! places ( ! fix$ />s1 9 ord] to f9d out ! s mu* desir$ longitude at sea1 = ! p]fect+ ! art ( navigation4 ,! s mu* desir$ longitude at sea is1 inde$1 a va/ly important ?+ to a m>itime nation l ,engl&4 ,& only 9 comp>atively rec5t ye>s has x become possible & easy = vessels to be navigat$ ) safety & conv5i5ce ^u long voyages4 ,! writ] 0 well acqua9t$ ) an old sea-capta9 ( ,new ,york1 :o _h comm&$ "o ( ! e>lie/ transatlantic /eam]s1 & :o di$ only a few ye>s ago4 ,he _h a goodly /ore ( ocean y>n1 fit & ready = ! sp9n+1 if he c\ld b f9d someone :o1 l himself1 _h kn[n & lov$ ! ocean4 ,9 8 e>ly sea-go+ days1 only ! weal?ie/ ( capta9s own$ *ronomet]s4 ,?is in/rum5t is n[ consid]$ indisp5sable 9 navigation1 b at t "t x 0 a new inv5tion1 v r>e & co/ly4 ,^u a c]ta9 voyage f ,engl& to ,rio ,janeiro1 9 ,s\? ,am]ica1 ! old capta9 c\ld rememb] ! foll[+ odd me?od ( navigation3 ,! %ip 0 /e]$ by compass to ! s\?w>d & we/w>d1 m or less1 until ! skipp]'s antique quadrant %[$ t !y _h ab\t rea*$ ! latitude ( ,rio4 ,!n !y swung h] on a c\rse due we/ by compass1 & away %e w5t = ,rio1 rely+ on ! look\t man =w>d to keep ! %ip f runn+ a%ore4 ,= aft] a c]ta9 lapse ( "t1 be+ ignorant ( ! longitude1 !y c\ld n "k :e!r !y w\ld raise ! l& )9 an h\r or 9 six weeks4 ,we are glad ( an opportunity to put ?is /ory on record1 = ! "t is n f> di/ant :5 !re w be no man left among ! liv+ :o c rememb] h[ %ips 7 tak5 across ! seas 9 ! good old days be=e *ronomet]s4 ,anyone :o has ev] be5 a pass5g] on a great transatlantic l9] ( to-day kn[s :at an important1 impos+ p]sonage is ! brass-b\nd skipp]4 ,a v diff]5t creature is he on ! deck ( 8 %ip f ! mode/ seaf>+ man we meet on l&1 clad = ! "t be+ 9 8 %ore-go+ togs4 ,b ! capta9's dignity is n all brass buttons & gold braid4 ,he has beh9d him ! p[]ful support ( a deep1 delightful my/]y4 ,he x is :o takes ! sun at noon1 & f9ds out ! %ip's pa? at sea4 ,& 9 tru?1 reg>d$ m]ely z a sci5tific exp]im5t1 ! guid+ ( a vessel across ! unm>k$ trackless ocean has few equals )9 ! :ole range ( human k4 ,x is our purpose "h to expla9 q briefly ! mann] 9 :i* ?is seem+ impossibility is accompli%$4 ,we %all n be able to g suffici5tly into details to enable him :o reads to run & navigate a magnific5t /eam]4 ,b we hope to dim9i% some:at t small "p ( ! capta9's va/ dignity :i* dep5ds ^u 8 my/]i\s op]ations ) ! sextant4 ,to beg91 !n1 ) ! sextant itself4 ,x is no?+ b an in/rum5t ) :i* we c measure h[ high up ! sun is 9 ! sky4 ,n[1 ev]yone kn[s t ! sun sl[ly climbs ! sky 9 ! morn+1 rea*es its greate/ height at noon1 & !n sl[ly s9ks aga9 9 ! aft]noon4 ,! capta9 simply beg9s to wat* ! sun ?r\gh ! sextant %ortly be=e noon1 & keeps at x until he discov]s t ! sun is j beg9n+ to desc5d4 ,t is ! in/ant ( noon on ! %ip4 ,! capta9 quickly glances at ! *ronomet]1 or calls out noon to an (fic] :o is ne> t in/rum5t4 ,& s ! error ( ! *ronomet] becomes kn[n !n & !re )\t any fur!r a/ronomical calculations :atev]4 ,navigators c also f9d ! *ronomet] error by sextant obs]vations :5 ! sun is a long way f noon4 ,! me?ods ( do+ ?is are some:at less simple ?an = ! noon obs]vation2 !y belong to ! details ( navigation1 into :i* we _c ent] "h4 ,incid5tally1 ! capta9 also notes ) ! sextant h[ high ! sun 0 9 ! sky at ! noon obs]vation4 ,he has 9 8 my/]i\s *>t-room "s pr9t$ a/ronomical tables1 :i* tell him 9 :at t]re/rial latitude ! sun w h precisely t height on t p>ticul> day ( ! ye>4 ,?us ! t]re/rial latitude becomes kn[n easily en\gh1 & if only ! capta9 c\ld get 8 longitude too1 he w\ld "k j :]e 8 %ip 0 t day at noon4 ,we h se5 t ! sextant obs]vations furni% ! error ( ! *ronomet] accord+ to %ip's "t4 ,9 o!r words1 ! capta9 is 9 possession ( ! correct local "t 9 ! place :]e ! %ip actually is4 ,n[1 if he also _h ! correct "t at t mom5t ( "s well-kn[n place on %ore1 he w\ld "k ! diff]5ce 9 "t betwe5 t place on %ore & ! %ip4 ,b e travell] by l& or sea is aw>e t !re are always diff]5ces ( "t betwe5 diff]5t places on ! e>?4 ,if a wat* be "r on leav+ ,new ,york1 = in/ance1 x w be mu* too fa/ on arriv+ at ,*icago or ,san ,francisco2 ! f>!r y g ! l>g] becomes ! error ( y\r wat*4 ,9 fact1 if y c\ld f9d out h[ mu* y\r wat* _h gone into error1 y w\ld 9 a s5se "k h[ f> ea/ or we/ y _h travell$4 ,n[ ! capta9's *ronomet] is set to correct ,gre5wi* "t on %ore be=e ! %ip leaves port4 ,8 obs]vations hav+ !n told him h[ mu* ?is is wrong on t p>ticul> day1 & 9 t p>ticul> spot :]e ! %ip is1 he kn[s at once j h[ f> he has travell$ ea/ or we/ f ,gre5wi*4 ,9 o!r words1 he kn[s 8 longitude f ,gre5wi*1 = longitude is no?+ m ?an di/ance f ,gre5wi* 9 an ea/-&-we/ direction1 j z latitude is only di/ance f ! equator measur$ 9 a nor?-&-s\? direction4 ,gre5wi* obs]vatory is usually select$ z ! beg9n+ ( ?+s = measur+ longitudes1 because x is almo/ ! olde/ ( exi/+ a/ronomical e/abli%m5ts1 & belongs to ! mo/ prom95t m>itime nation1 ,engl&4 ,"o ( ! mo/ int]e/+ bits ( a/ronomical hi/ory 0 enact$ 9 connection ) ?is matt] ( longitude4 ,f :at has be5 said1 x is cle> t ! %ip's longitude w be obta9$ correctly only if ! *ronomet] has kept exact "t s9ce ! dep>ture ( ! %ip f port4 ,ev5 a v small error ( ! *ronomet] w ?r[ out ! longitude a good _m miles1 & we c und]/& readily t x mu/ be difficult 9 ! extreme to con/ruct a me*anical contrivance capable ( keep+ exact "t :5 subject$ to ! roll+ & pit*+ ( a vessel at sea4 ,x 0 z rec5tly z ! ye> #agcf t ! fir/ in/rum5t capable ( keep+ any?+ l accurate "t at sea 0 successfully complet$4 ,x 0 ! "w ( an ,engli% wat*mak] nam$ ,john ,h>rison1 & is "o ( ! few great improvem5ts 9 matt]s sci5tific :i* ! _w owes to a desire = w9n+ a money prize4 ,x appe>s t 9 #agad a committee 0 appo9t$ by ! ,h\se ( ,commons1 ) no less a p]son ?an ,sir ,isaac ,newton himself z "o ( its memb]s1 to consid] ! desirability ( (f]+ gov]nm5tal enc\ragem5t = ! inv5tion ( "s means ( f9d+ ! longitude at sea4 ,f9ally1 ! ,briti% ,gov]nm5t (f]$ a rew>d ( #ej1jjj = an in/rum5t :i* w\ld f9d ! longitude )9 sixty miles2 #ge1jjj1 if )9 =ty miles1 & #ajj1jjj1 if )9 ?irty miles4 ,h>rison's *ronomet] 0 f9i%$ 9 #agcf1 b he did n receive ! f9al paym5t ( 8 prize until #agfd4 ,we %all n ent] into a detail$ acc\nt ( ! vexati\s delays & (ficial proc$ures to :i* he 0 =c$ to submit dur+ ^? tw5ty-eight long ye>s4 ,x is a matt] ( satisfaction t ,h>rison liv$ to receive ! money :i* he _h e>n$4 ,he _h ! g5ius to plan & ma/] intricate me*anical details1 b p]haps he lack$ 9 "s degree ! ability ( tongue & p5 to br+ !m home to o!rs4 ,?is may be ! reason he is s little kn[n1 ?\gh x 0 8 =tune to contribute s l>ge & ess5tial a "p to ! p]fection ( mod]n navigation4 ,let u hope ?is brief m5tion may s]ve to recall 8 memory f oblivion ev5 = a fleet+ mom5t2 t we may n h writt5 9 va9 ( t longitude to :i* 8 life 0 giv54 ,,! ,,pleiades ,fam$ 9 leg5d2 sung by e>ly m9/rels ( ,p]sia & ,h9du/an2 --l a sw>m ( fire-flies tangl$ 9 a silv] braid2 yond] di/ant mi/y little cl\d ( ,pleiades has always won & held ! imag9ation ( m54 ,b x 0 n only = ! inspiration ( poets1 = quick5+ fancy into song1 t ! sev5 daught]s ( ,atlas 7 fix$ ^u ! firmam5t4 ,! problems pres5t$ by ?is gr\p ( />s to ! unobtrusive sci5tific inve/igator are among ! mo/ int]e/+ kn[n to a/ronomy4 ,_! solution is /ill v incomplete1 b :at we h already le>n$ may be c\nt$ ju/ly among ! ri*e/ spoils br\ght back by sci5ce f ! /or$ treasure-h\se ( ,nature's secrets4 ,! true /ud5t ( a/ronomy is animat$ by no m]e vulg> curiosity to pry into ?+s hidd54 ,if he seeks ! conceal$ spr+s t move ! complex visible me*anism ( ! heav5s1 he does s because 8 imag9ation is r\s$ by ! gr&eur ( :at he sees2 & deep d[n )9 him /irs ! true love ( ! arti/ = 8 art4 ,= x is inde$ a f9e art1 t sci5ce ( a/ronomy4 ,x c h be5 no m]e *ance t has mass$ ! ,pleiades f among _! fell[ />s4 ,m5 ( ord9>y eyesight see b a half-doz5 di/9ct objects 9 ! clu/]2 ^? ( acut] vision c c\nt f\rte52 b x is n until we apply ! space-p5etrat+ p[] ( ! telescope t we realize ! extraord9>y scale ^u :i* ! sy/em ( ! ,pleiades is con/ruct$4 ,) ! ,p>is in/rum5t ,wolf 9 #ahgf catalogu$ #fbe />s 9 ! gr\p2 & ! se>*+ photographic survey ( ,h5ry 9 #ahhg reveal$ no less ?an #b1cbf di/9ct />s )9 & ne> ! filmy gauze ( nebul\s matt] always s conspicu\s a feature ( ! ,pleiades4 ,! means at our disposal = ! /udy ( /ell> di/ances are b feeble4 ,only 9 ! case ( a v small numb] ( />s h we be5 able to obta9 ev5 s mu* z an approximate e/imate ( di/ance4 ,! mo/ p[]ful obs]vational ma*9]y1 ?\gh direct$ by ! tri$ skill ( exp]i5ce1 has n suffic$ to s\nd ! pr(\nd] dep?s ( space4 ,! ,pleiad />s are among ^? = :i* no measurem5t ( di/ance has yet be5 made1 s t we d n "k :e!r !y are all equally f> away f u4 ,we see !m project$ on ! d>k backgr\nd ( ! cele/ial vault2 b we _c tell f actual measurem5t :e!r !y are all situat$ ne> ! same po9t 9 space4 ,x may be t "s are immeasurably clos] to u ?an are ! great mass ( _! companions2 possibly we look ?r\gh ! clu/] at o!rs f> beh9d x1 cl++1 z x 71 to ! v fr+e ( ! visible univ]se4 ,f>!r on we %all f9d evid5ce t some?+ l ?is really is ! case4 ,b "u no circum/ances is x reasonable to suppose t ! :ole body ( />s c be /rung out at all sorts ( di/ances ne> a /raight l9e po9t+ 9 ! direction ( ! visible clu/]4 ,su* a di/ribution may p]haps rema9 among ! possibilities1 s long z we _c measure directly ! actual di/ances ( ! individual />s4 ,b sci5ce nev] accepts a m]e possibility aga9/ :i* we c m>%al /rong circum/antial evid5ce4 ,we may conclude on g5]al pr9ciples t ! ga!r+ ( ^! _m objects into a s+le close assemblage d5otes community ( orig9 & int]e/s4 ,! ,pleiades !n really belong to "o ano!r4 ,:at is ! nature ( _! mutual tie8 ,:at is _! my/]y1 & c we solve x8 ,! mo/ obvi\s !ory is1 ( c\rse1 sugge/$ by :at we "k to be true )9 our own sol> sy/em4 ,we owe to ,newton ! beautiful conception ( gravitation1 t unique law by means ( :i* a/ronom]s h be5 enabl$ to r$uce to p]fect ord] ! seem+ tangle ( planet>y evolutions4 ,! law really am\nts1 9 effect1 to ?is3 ,all objects susp5d$ )9 ! vacancy ( space attract or pull "o ano!r4 ,h[ !y c d ?is )\t a visible connect+ l9k betwe5 !m is a my/]y :i* may always rema9 unsolv$4 ,b my/]y z x is1 we mu/ accept x z an asc]ta9$ fact4 ,x is ?is pull ( gravitation t holds toge!r ! sun & planets1 =c+ !m all to foll[ out _! due & prop] pa?s1 & s to cont9ue ?r\gh\t an unbrok5 cycle until ! great survivor1 ,"t1 %all be no m4 ,?is same gravitational attraction mu/ be at "w among ! ,pleiades4 ,!y1 too1 l ourselves1 mu/ h b\nds & orbits set & int]wov51 revolutions & gyrations f> m complex ?an ! sol> sy/em kn[s4 ,! visual discov]y ( su* motion ( rotation among ! ,pleiades may be call$ "o ( ! press+ problems ( a/ronomy to-day4 ,we feel sure t ! "t is ripe1 & t ! discov]y is actually be+ made at ! pres5t mom5t3 = a g5]ation ( m5 is n too great a p]iod to call a mom5t1 :5 we h to deal ) cosmic "t4 ,x is inde$ ! lack ( obs]vations ext5d+ ?r\gh suffici5t c5turies t /ays our h& f grasp+ ! covet$ result4 ,! ,pleiades are s f> f u t we _c be sure ( *anges among !m4 ,magnitudes are always relative4 ,x matt]s n h[ l>ge ! actual movem5ts may be2 if !y are extremely small 9 comp>ison ) our di/ance1 !y mu/ %r9k to no?+ness 9 our eyes4 ,trembl+ on ! v]ge ( invisibility1 elusive1 !y are 9 t bord]l& :]e sci5ce z yet b feels h] way1 ?\gh c]ta9 t ! way is !re4 ,! f\ndations ( exact mod]n k ( ! gr\p 7 laid by ,bessel ab\t #ahdj4 ,) ! mode/y *>act]i/ic ( ! great1 he says q simply t he has made a numb] ( measures ( ! ,pleiades1 ?9k+ t ! "t may come :5 a/ronom]s w be able to f9d "s evid5ce ( motion4 ,9 ?is unassum+ way he prefaces :at is /ill ! classic model ( precision & ?or\ghness 9 "w ( ?is k9d4 ,bessel cle>$ ! gr\nd = a /udy ( int]-/ell> motion )9 ! close />-clu/]s2 & x is probable t only by su* /udy may we hope to demon/rate ! univ]sality ( ! law ( gravitation 9 cosmic space4 ,bessel's acut5ess 9 =eca/+ ! direction ( com+ rese>* 0 amply v]ifi$ by ! "w ( ,elk9 9 #ahhe at ,yale ,college4 ,provid$ ) a m mod]n in/rum5t1 b simil> to ,bessel's1 ,elk9 0 able to repeat 8 obs]vations ) a slight increase ( precision4 ,motions 9 ! int]val ( =ty-five ye>s1 suffici5tly great to h9t at com+ possibilities1 7 %[n conclusively to exi/4 ,six />s at all ev5ts h be5 fairly exclud$ f ! gr\p on acc\nt ( _! peculi> motions %[n by ,elk9's rese>*4 ,x is possible t !y are m]ely se5 9 ! backgr\nd ?r\gh ! int]/ices ( ! clu/] itself1 or !y may be susp5d$ betwe5 u & ! ,pleiades1 9 ei!r case hav+ no real connection ) ! gr\p4 ,f9ally1 ^! obs]vations make x reasonably c]ta9 t _m ( ! rema9+ mass ( />s really con/itute a unit aggregation 9 space4 ,a/ronom]s ( a com+ g5]ation w aga9 repeat ! ,besselian "w4 ,at pres5t we h be5 able to use 8 me?od only = ! sep>ation f ! true ,pleiades ( *ance />s t happ5 to lie 9 ! same direction4 ,let u hope t man %all exi/ long en\gh ^u ?is e>? to see ! clu/]$ />s !mselves beg9 & c>ry out su* gyrations z gravitation imposes4 ,^! w d\btless be ( a k9d n ev5 sugge/$ by ! less] complexities ( our sol> sy/em4 ,= ! mo/ wond]ful ?+ ( all ab\t ! ,pleiades seems to po9t to an intricacy ( /ructure ^: details may be de/9$ to %ake ! confid5ce ( ! pr(\nde/ ma!matician4 ,!re is an extraord9>y nebul\s cond5sation t seems to p]vade ! entire space occupi$ by ! /ell> con/itu5ts ( ! gr\p4 ,! />s are swimm+ 9 a v]itable sea ( lum9\s cl\d4 ,!re are filmy t5u\s places1 & aga9 cond5s+ :irls ( mat]ial d\btless /ill 9 ! gase\s or pla/ic /age4 ,mo/ noticeable ( all are c]ta9 almo/ /raight l9es ( nebula t connect s]ies ( />s4 ,9 "o case1 %[n ^u a photograph made by ,h5ry at ,p>is1 six />s are /rung out ^u su* a hazy l9e4 ,we might give play to fancy1 & see 9 ?is ! result ( "s va/ eruption ( gase\s matt] t has already begun to solidify "h & !re into /ell> nuclei4 ,b s\nd sci5ce gives n too great fre$om to m]e speculative !ories4 ,h] duty has be5 f\nd 9 quiet rese>*1 & h] greate/ rew>ds h fl[$ f imag9ative speculation1 only :5 temp]$ by pure reason4 ,,! ,,pole-,,/> ,"o ( ! mo/ brilliant obs]vations ( ! la/ few ye>s is ,campbell's rec5t discov]y ( ! triple "* ( ?is />4 ,c5turies & c5turies ago1 :5 a/ronomy1 t v5]able anci5t among ! sci5ces1 0 b an infant1 ! pole-/> mu/ h be5 consid]$ ! v olde/ ( obs]v$ heav5ly bodies4 ,9 ! beg9n+ x 0 ! only sure guide ( ! navigator at night1 j z to ?is day x is ! f\ndation-/one = all obs]vational /ell> a/ronomy ( precision4 ,!re has nev] be5 a "t 9 ! hi/ory ( a/ronomy :5 ! pole-/> might n h be5 call$ ! mo/ frequ5tly measur$ object 9 ! sky ( night4 ,s x is inde$ /range t we %\ld f9d out some?+ altoge!r new ab\t x aft] all ^! ages ( /udy4 ,b ! importance ( ! discov]y re/s ^u a sur] f\ndation ?an ?is4 ,! me?od by :i* x has be5 made is almo/ a new "o 9 ! sci5ce4 ,a g5]ation ago1 m5 ?\ght ! p]fect sci5ce1 = s we love to call a/ronomy1 c\ld advance only by increas+ a little ! exact precision ( obs]vation4 ,! citadel ( p]fect tru? might be m closely inve/$2 ! =ces ( sci5ce might pu% =w>d /ep by /ep2 ! ma*9]y ( rese>* might be /r5g!n$1 b t a new eng9e ( inve/igation w\ld be discov]$ capable ( p5etrat+ :]e no telescope c ev] rea*1 ?is1 inde$1 seem$ f> beyond ! livelie/ hope ( sci5ce4 ,ev5 ! discov]] ( ! spectroscope c\ld nev] h dream$ ( its possibilities1 c\ld nev] h =ese5 its successes1 its triumphs4 ,! v "n ( ?is in/rum5t sugge/s my/]y to ! popul> m9d4 ,x is set d[n at once among ! ?+s too difficult1 too intricate1 too ab/ruse to und]/&4 ,yet 9 its ess5tials !re is no?+ ab\t ! spectroscope t _c be made cle> 9 a few words4 ,ev5 ! mod]n undulatory !ory ( light itself is t]rible only 9 ! l5g? ( its "n4 ,anyone :o has se5 ! waves ( ocean roll1 roll1 & ev] aga9 roll 9 ^u ! %ore1 c =m a v good notion ( h[ light moves4 ',tis j su* a s]ies ( roll+ waves2 />t$ p]haps f "s brilliant con/ellation f> out ^u ! conf9+ b\nds ( ! visible univ]se1 or p]haps com+ f a humble light ^u ! /ud5t's table2 yet x is nev] any?+ b a succession ( roll+ waves4 ,only1 unlike ! waves ( ! sea1 light waves are all excessively small4 ,we %\ld call "o ^: l5g? 0 a tw5ty-?\s&? ( an in* a big "o6 ,n[ ! human eye possesses ! prop]ty ( receiv+ & und]/&+ ^! little waves4 ,! process is an unconsci\s "o4 ,let b a set ( ^! t9y waves roll up1 z x 71 out ( ! va/ ocean ( space & imp+e ^u ! eye1 & all ! ph5om5a ( light & color become :at we call visible4 ,we see ! light4 ,& h[ does all ?is f9d an application 9 a/ronomy8 ,n to ent] too mu* into te*nical details1 we may say t ! spectroscope is an in/rum5t :i* enables u to measure ! l5g? ( ^! light waves1 ?\gh _! l5g? is s exce$+ly small4 ,! day has inde$ gone by :5 t :i* poets love to call ! ,book ( ,nature 0 pr9t$ 9 type t c\ld be read by ! eye unaid$4 ,telescope1 microscope1 & spectroscope are ess5tial n[ to him :o w\ld p5etrate any ( ,nature's secrets4 ,b measurem5ts ) a telescope1 l eye obs]vations1 are limit$ /rictly to det]m9+ ! directions 9 :i* we see ! heav5ly bodies4 ,ev] s9ce ! beg9n+ ( ?+s1 :5 old ,hipp>*us & ,ulugh ,beg made ! fir/ rude b successful attempts to catalogue ! />s1 ! eye & telescope h be5 able to measure only su* directions4 ,we aim ! telescope at a />1 & record ! direction 9 :i* x 0 po9t$4 ,di/ances 9 a/ronomy c nev] be measur$ directly4 ,all t we "k ( !m has be5 obta9$ by calculations bas$ ^u ! ,newtonian law ( gravitation & obs]vations ( directions4 ,n[ ! spectroscope seems to (f] a sort ( exception to ?is rule4 ,suppose we c measure ! wave-l5g?s ( ! light s5t u f a />4 ,suppose aga9 t ! /> is itself mov+ swiftly t[>d u ?r\gh space1 :ile cont9ually sett+ 9 motion ! waves ( light t are ultimately to rea* ! wait+ a/ronom]4 ,evid5tly ! light waves w be cr[d$ toge!r some:at on acc\nt ( ! />'s motion4 ,m waves p] second w rea* u ?an w\ld be receiv$ f a /> at re/4 ,x is z ?\gh ! light waves 7 compress$ or %ort5$ a little4 ,& if ! /> is leav+ u1 in/ead ( com+ ne>]1 opposite effects w occur4 ,we h !n b to comp>e spectroscopically />light ) "s artificial s\rce ( light 9 ! obs]vatory 9 ord] to f9d out :e!r ! /> is approa*+ u or rec$+ f u4 ,& by a simple process ( calculation ?is /ell> motion c be obta9$ 9 miles p] second4 ,?us we c n[ actually measure directly1 9 a c]ta9 s5se1 l9e> spe$ 9 /ell> space1 ?\gh we are /ill )\t ! means ( gett+ directly at /ell> di/ances4 ,b ! mo/ wond]ful ?+ ( all ab\t ^! spectroscopic measures is ! fact t x makes no diff]5ce :atev] h[ f> away is ! /> "u obs]vation4 ,:at we le>n ?r\gh ! spectroscope comes f a /udy ( ! waves !mselves1 & x is ( no consequ5ce h[ f> !y h travell$1 or h[ long !y h be5 a-com+4 ,= x mu/ n be suppos$ t ^! waves consume no "t 9 pass+ f a di/ant /> to our own sol> sy/em4 ,x is true t !y move exce$+ fa/2 c]ta9ly #ahj1jjj miles p] second may be call$ rapid motion4 ,b if ?is cosmic velocity ( light is trem5d\s1 s also are cosmic di/ances correspond+ly va/4 ,light ne$s to move quickly com+ f a />1 = ev5 at ! rate ( motion we h m5tion$ x requires _m ye>s to rea* u f "s ( ! m di/ant con/ellations4 ,x has be5 well said t an obs]v] on "s f>-away />1 if end[$ ) ! p[] to see at any di/ance1 h[ev] great1 might at ?is mom5t be look+ on ! ,crusad]s proce$+ f ,europe aga9/ ! ,s>ac5 at ,j]usalem4 ,= x is q possible t n until n[ has ! light :i* w\ld make ! e>? visible _h "t to rea* him4 ,yet di/ant z su* an obs]v] might be1 light f ! /> on :i* he /ood c\ld be measur$ 9 ! spectroscope1 & w\ld infallibly tell u :e!r ! e>? & /> are approa*+ 9 space or gradually draw+ f>!r asund]4 ,! pole-/> is n "o ( ! m di/ant /ell> sy/ems4 ,we d n "k h[ f> x is f u v exactly1 b c]ta9ly n less ?an =ty or fifty ye>s are necess>y = its light to rea* u4 ,! /> might h gone out ( exi/5ce tw5ty ye>s ago1 & we n yet "k ( x1 = we w\ld /ill be receiv+ ! light :i* began its long j\rney to u ab\t #ahej or #ahfj4 ,b no matt] :at may be its di/ance1 ,campbell f\nd by c>eful obs]vations1 made 9 ! latt] "p ( #ahif1 t ! pole-/> 0 !n approa*+ ! e>? at ! rate ( ab\t twelve miles p] second4 ,s f> !re 0 no?+ especially rem>kable4 ,b 9 ,augu/ & ,septemb] ( ! pres5t ye> tw5ty-six c>eful det]m9ations 7 made1 & ^! %[$ t n[ ! rate ( approa* v>i$ betwe5 ab\t five & n9e miles p] second4 ,m a/oni%+ /ill1 !re 0 a uni=m p]iod 9 ! *anges ( velocity4 ,9 ab\t f\r days ! rate ( motion *ang$ f ab\t five to n9e miles & back aga94 ,& ?is v>iation kept on ) great regul>ity4 ,e successive p]iod ( f\r days saw a complete cycle ( velocity *ange =w>d & back betwe5 ! same limits4 ,!re c be b "o reasonable explanation4 ,?is /> mu/ be a d\ble1 or b9>y />4 ,! two compon5ts1 "u ! influ5ce ( p[]ful mutual gravitational attraction1 mu/ be revolv+ 9 a mighty orbit4 ,yet ?is va/ orbit1 z a :ole1 ) ! two great />s 9 x1 mu/ be approa*+ our "p ( ! univ]se all ! "t4 ,= ! spectroscope %[s ! velocity ( approa* to increase & dim9i%1 inde$1 b x is always pres5t4 ,"h1 !n1 is ?is great /ell> sy/em1 hav+ a f\r-day revolution ( its own1 & yet sw++ rapidly ?r\gh space 9 our direction4 ,nor is ?is all4 ,"o ( ! compon5t />s mu/ be ne>ly or q d>k2 else its pres5ce w\ld infallibly be detect$ by our in/rum5ts4 ,& n[ we come to ! mo/ a/oni%+ ?+ ( all4 ,h[ comes x t ! av]age rate ( approa* ( ! f\r-day sy/em1 z a :ole1 *ang$ betwe5 #ahif & #ahii8 ,9 #ahif only ?is velocity ( ! :ole sy/em 0 det]m9$1 ! f\r-day p]iod rema9+ undiscov]$ until ! m num]\s obs]vations ( #ahii4 ,b ev5 )\t consid]+ ! f\r-day p]iod1 ! *ang+ velocity ( ! entire sy/em (f]s "o ( ^? problems t exact sci5ce c treat only by ! help ( ! imag9ation4 ,!re mu/ be "s o!r great c5tre ( attraction1 "s cosmic giant1 hold+ ! visible d\ble pole-/> "u its control4 ,?us1 t :i* we see1 & call ! pole-/>1 is 9 reality ?read+ its pa? ab\t ! ?ird & greate/ memb] ( ! sy/em1 itself situat$ 9 space1 we "k n :]e4 ,illu/ration3 ,spiral ,nebula 9 ,con/ellation ,leo4 ,photograph$ by ,keel]1 ,febru>y #bd1 #aijj4 ,exposure1 ?ree h\rs1 fifty m9utes4 ,,nebul ,scatt]$ ab\t "h & !re among ! />s are c]ta9 pat*es ( fa9t lum9osity call$ by a/ronom]s ,nebul4 ,^! little cl\ds ( filmy light are among ! mo/ fasc9at+ ( all ! kaleidoscopic ph5om5a ( ! heav5s2 = x ne$s b a glance at "o ( !m to give ! impression t "h be=e u is ! /uff ( :i* worlds are made4 ,all our k ( ,nature leads u to expect 9 h] f9i%$ "w ! result ( a s]ies ( gradual processes ( developm5t4 ,highly organiz$ ph5om5a su* z ^? exi/+ 9 our sol> sy/em did n spr+ into p]fection 9 an in/ant4 ,influ5tial =ces1 easy to imag9e1 b difficult to def9e1 mu/ h direct$ ! sl[1 sure trans=mation ( elem5tal matt] into sun & planets1 ?+s & m54 ,!re=e a /udy ( ^? =ces & ( _! probable action ^u nebul> mat]ial has always ex]t$ a /rong attraction ^u ! acute/ ?9k]s among m5 ( exact sci5ce4 ,our k ( ! nebul is ( two k9ds--t :i* has be5 asc]ta9$ f obs]vation z to _! appe>ance1 size1 di/ribution1 & di/ance2 & t :i* is bas$ ^u hypo!ses & !oretical reason+ ab\t ! cond5sation ( /ell> sy/ems out ( nebul> masses4 ,x s happ5s t our obs]vational mat]ial has receiv$ a v important addition q rec5tly ?r\gh ! application ( photography to ! del9eation ( nebul1 & ?is we %all describe f>!r on4 ,two nebul only are visible to ! unaid$ eye4 ,! bright] ( ^! is 9 ! con/ellation ,&rom$a2 x is ( oval or elliptical %ape1 & has a di/9ct c5tral cond5sation or nucleus4 ,^u a photograph by ,rob]ts x appe>s to h sev]al conc5tric r+s surr\nd+ ! nebula prop]1 & gives ! g5]al impression ( a flat r\nd disk =e%ort5$ into an oval %ape on acc\nt ( ! obs]v]'s position n be+ squ>e to ! surface ( ! disk4 ,v rec5t photographs ( ?is nebula1 made ) ! ?ree-foot reflect+ telescope ( ! ,lick ,obs]vatory1 br+ out ! fact t x is really spiral 9 =m1 & t ! outly+ nebul\s r+s are only p>ts ( ! spires 9 a great cosmic :orl4 ,illu/ration3 ,nebula 9 ,&rom$a4 ,l[] object 9 ! photograph is a ,comet4 ,photograph$ by ,b>n>d1 ,novemb] #ba1 #ahib4 ,?is ,&rom$a nebula is ! "o 9 :i* ! tempor>y /> ( #ahhe appe>$4 ,x blaz$ up q sudd5ly ne> ! app>5t c5tre ( ! nebula1 & cont9u$ 9 view = six mon?s1 fad+ f9ally beyond ! rea* ( our mo/ p[]ful telescopes4 ,!re c be little d\bt t ! /> 0 actually 9 ! nebula1 & n m]ely se5 ?r\gh x1 ?\gh 9 reality situat$ 9 ! extreme outly+ "p ( space at a di/ance immeasurably great] ?an t sep>at+ u f ! nebula itself4 ,su* an accid5tal sup]position ( nebula & /> might ev5 be due to sudd5 inc&esc5ce ( a new /> betwe5 u & ! nebula4 ,9 su* a case we %\ld see ! /> project$ ^u ! surface ( ! nebula1 s t ! sup]position w\ld be id5tical ) t actually obs]v$4 ,!re=e1 :ile x is1 inde$1 possible t ! /> may h be5 ei!r f> beh9d ! nebula or 9 front ( x1 we mu/ accept z m probable ! supposition t !re 0 a real connection betwe5 ! two4 ,9 t case !re is little d\bt t we h actually obs]v$ "o ( ^? cataclysms t m>k successive /eps ( cosmic evolution4 ,we h no ?or\ghly satisfactory !ory to acc\nt = su* an explosive cata/rophe )9 ! body ( ! nebula itself4 ,! o!r nak$-eye nebula is 9 ! con/ellation ,orion4 ,9 ! telescope x is a m /rik+ object1 p]haps1 ?an ! ,&rom$a nebula2 = x has no well-def9$ geometrical =m1 b consi/s ( an imm5se odd-%ap$ mass ( light enclos+ & surr\nd+ a numb] ( />s4 ,x is unque/ionably ( a v complicat$ /ructure1 & is1 !re=e1 less easily /udi$ & expla9$ ?an ! nebul ( simpl] =m4 ,!re is no d\bt t ! ,orion nebula is compos$ ( lum9\s gas1 & is n m]ely a clu/] ( small />s too num]\s & too ne> toge!r to be sep>at$ f ea* o!r1 ev5 9 our mo/ p[]ful telescopes4 ,x 01 inde$1 suppos$1 until ab\t =ty ye>s ago1 t all ! nebul are simply irresolvable />-clu/]s2 b we n[ h indisputable evid5ce1 d]iv$ f ! spectroscope1 t _m nebul are compos$ ( true gases1 simil> to ^? ) :i* we exp]im5t 9 *emical laboratories4 ,?is spectroscopic pro( ( ! gase\s "* ( nebul is "o ( ! mo/ important discov]ies contribut$ by t in/rum5t to our small /ock ( facts conc]n+ ! /ructure ( ! sid]eal univ]se4 ,com+ n[ to ! small] nebul1 we f9d a great div]sity ( =m & appe>ance4 ,"s are r+-%ap$1 p]haps hav+ a less brilliant nebulosity )9 ! r+4 ,_m %[ a c5tral cond5sation ( disk-l appe>ance 7planet>y nebul71 or h simply a /> at ! c5tre 7nebul\s />s74 ,altoge!r ab\t t5 ?\s& su* objects h be5 catalogu$ by successive g5]ations ( a/ronom]s s9ce ! inv5tion ( ! telescope1 & mo/ ( ^! h be5 report$ z oval 9 =m4 ,n[ we h already ref]r$ to ! important addition to our k ( ! nebul obta9$ by rec5t photographic obs]vations2 & ?is addition consi/s 9 ! discov]y t mo/ ( ^! oval nebul are 9 reality spirals4 ,inde$1 x appe>s t ! spiral type is ! normal type1 & t nebul ( irregul> or o!r =ms are exceptions to ! g5]al rule4 ,ev5 ! great ,&rom$a nebula1 z we h se51 is n[ recogniz$ z a spiral4 ,! in/rum5t ) :i* its convolute /ructure 0 discov]$ is a ?ree-foot reflect+ telescope1 made by ,common ( ,engl&1 & n[ m\nt$ at ! ,lick ,obs]vatory1 9 ,cali=nia4 ,! late ,pr(essor ,keel] devot$ mu* ( 8 "t to photograph+ nebul dur+ ! la/ ye> or two4 ,he 0 able to e/abli% ! important fact j m5tion$1 t mo/ nebul =m]ly ?\ght to be m]e ovals1 turn out to be spiral :5 br\ght "u ! m se>*+ scrut9y ( ! photographic plate appli$ at ! focus ( a telescope ( great size1 & ) an exposure to ! feeble nebul> light ext5d+ ?r\gh ?ree or f\r consecutive h\rs4 ,_m ( ! spirals h m ?an a s+le volute4 ,x is z ?\gh "o 7 to atta* a numb] ( v flexible rods to an axle1 l spokes ( a :eel )\t a rim & !n revolve ! axle rapidly4 ,! flexible rods w\ld b5d "u ! rapid rotation1 & =m a s]ies ( spiral curves n unlike _m ( ^! nebul4 ,inde$1 x is impossible to escape ! conviction t ^! great cele/ial :orls are :irl+ ar\nd an axis4 ,& x is mo/ important 9 ! /udy ( ! gr[? ( worlds1 to recognize t ! type specim5 is a revolv+ spiral4 ,!re=e1 ! rotat+ flatt5$ globe ( inc&esc5t matt] po/ulat$ by ,laplace's nebul> hypo!sis w\ld make ( our sol> sy/em an exceptional _w1 & n a type ( /ell> evolution 9 g5]al4 ,keel]'s photographs h taught u "o ?+ m4 ,sc>cely is !re a s+le "o ( 8 negatives t does n %[ nebul previ\sly uncatalogu$4 ,x is e/imat$ t if ?is process ( photography c\ld be ext5d$ s z to cov] ! entire sky1 ! :ole numb] ( nebul w\ld add up to ! /up5d\s total ( #abj1jjj2 & ( ^! ! great majority w\ld be spiral4 ,:5 we approa* ! "q ( ! di/ribution ( nebul 9 diff]5t p>ts ( ! sky1 z %[n by _! catalogu$ positions1 we are met by a curi\s fact4 ,x appe>s t ! region 9 ! neighborhood ( ! ,milky ,way is especially poor 9 nebul1 :]eas ^! objects seem to clu/] 9 mu* l>g] numb]s ab\t ^? po9ts 9 ! sky t are f>!/ f ! ,milky ,way4 ,b we "k t ! ,milky ,way is ri*] 9 />s ?an any o!r "p ( ! sky1 s9ce x is1 9 fact1 made up ( /ell> bodies clu/]$ s closely t x is wellnigh impossible to see betwe5 !m 9 ! d5s] portions4 ,n[1 x _c be ! result ( *ance t ! />s %\ld t5d to congregate 9 ! ,milky ,way1 :ile ! nebul t5d to seek a position z f> f x z possible4 ,:atev] may be ! cause1 we mu/ conclude t ! sid]eal sy/em1 z we see x1 is 9 g5]al con/ruct$ ^u a s+le plan1 & does n consi/ ( a s]ies ( univ]ses scatt]$ at r&om ?r\gh\t space4 ,if we are to suppose t nebul turn into />s z a result ( cond5sation or any o!r *ange1 !n x is n a/oni%+ to f9d a m9imum ( nebul :]e !re is a maximum ( />s1 s9ce ! nebul w h be5 consum$1 z x 71 9 ! =mation ( ! />s4 ,illu/ration3 ,! ,dumb-,bell ,nebula4 ,photograph$ by ,keel]1 ,july #ca1 #ahii4 ,exposure1 ?ree h\rs4 ,x is nev] advisable to pu% philosophical speculation v f> :5 support$ by too sl5d] a basis ( fact4 ,b if we are to reg>d ! visible univ]se z made up on ! :ole ( a s+le sy/em ( bodies1 we may well ask "o or two que/ions to be answ]$ by speculative !ory4 ,we h said ! />s are n uni=mly di/ribut$ 9 space4 ,_! conc5tration 9 ! ,milky ,way1 =m+ a n>r[ b& divid+ ! sky into two v ne>ly equal p>ts1 mu/ be due to _! be+ actually mass$ 9 a ?9 disk or r+ ( space )9 :i* our sol> sy/em is also situat$4 ,?is ?9 disk project$ ^u ! sky w\ld !n appe> z ! n>r[ />-b& ( ! ,milky ,way4 ,n[1 suppose ?is disk has an axis p]p5dicul> to itself1 & let u imag9e a rotation ( ! :ole sid]eal sy/em ab\t t axis4 ,!n ! fact t ! visible nebul are congregat$ f> f ! ,milky ,way means t !y are actually ne> ! imag9>y axis4 ,possibly ! dim9i%$ velocity ( motion ne> ! axis may h some?+ to d ) ! pres5ce ( ! nebul !re4 ,possibly ! nebul !mselves h axes p]p5dicul> to ! plane ( ! ,milky ,way4 ,if s1 we %\ld see ! spiral nebul ne> ! ,milky ,way edgewise1 & ^? f> f x )\t =e%ort5+4 ,?us1 ! paucity ( nebul ne> ! ,milky ,way may be due 9 "p to ! increas$ difficulty ( see+ !m :5 look$ at edgewise4 ,inde$1 !re is no limit to ! possibilities ( hypo!tical reason+ ab\t ! nebul> /ructure ( our univ]se2 un=tunately1 ! :ole "q mu/ be plac$ = ! pres5t among ^? int5sely int]e/+ cosmic problems await+ elucidation1 let u hope1 9 ?is new c5tury4 ,,tempor>y ,,/>s ,no?+ c be m errone\s ?an to suppose t ! /ell> multitude has cont9u$ un*ang$ ?r\gh\t all g5]ations ( m54 ,et]nal fires poets h call$ ! />s2 yet !y burn l any little conflagration on ! e>?2 n[ fla%+ ) en]gy1 brilliant1 inc&esc5t1 & aga9 s9k+ into ! dull gl[ ( sm\ld]+ half-burn$ a%es4 ,x is ev5 probable t space conta9s _m d>k5$ orbs1 />s t may h ris5 9 con/ellations to adorn ! skies ( prehi/oric "t--n[ cold1 unse51 unkn[n4 ,s f> f deal+ ) an unv>y+ univ]se1 x is safe to say t sid]eal a/ronomy c advance only by ! discov]y ( *ange4 ,obs]vational sci5ce wat*es ) untir+ indu/ry1 & night hides few cele/ial ev5ts f ! ard5t scrut9y ( a/ronom]s4 ,old !ories are te/$ & new] ones (t5 p]fect$ by ! detection ( "s slight & previ\sly unsuspect$ alt]ation ^u ! face ( ! sky4 ,! int]pretation ( su* *anges is ! mo/ difficult task ( sci5ce2 x has tax$ ! acute/ intellects among m5 ?r\gh\t all "t4 ,if1 !n1 *anges c be se5 among ! />s1 :at are we to ?9k ( ! mo/ important *ange ( all1 ! blaz+ into life ( a new /ell> sy/em8 ,fifte5 times s9ce m5 began to write _! records ( ! skies has ! bir? ( a /> be5 se54 ,surely we may use ?is t]m :5 we speak ( ! sudd5 appe>ance ( a brilliant lum9>y :]e no?+ visible exi/$ be=e4 ,b we %all see fur!r on t sci5tific consid]ations make x highly probable t ! ph5om5on 9 "q does n really involve ! creation ( new matt]4 ,x is old mat]ial becom+ sudd5ly lum9\s = "s hidd5 reason4 ,9 fact1 :5ev] a new object ( great brilliancy has be5 discov]$1 x has be5 f\nd to lose its light aga9 q soon1 end+ ei!r 9 total ext9ction or at lea/ 9 comp>ative d>kness4 ,x is = ?is reason t ! "n tempor>y /> has be5 appli$ to cases ( ?is k9d4 ,! fir/ au!nticat$ in/ance dates f ! ye> #acd ,b4,c41 :5 a new /> appe>$ 9 ! con/ellation ,scorpio4 ,x 0 ?is /> t l$ ,hipp>*us to con/ruct 8 /ell> catalogue1 ! fir/ ev] made4 ,x occurr$ to him1 ( c\rse1 t !re c\ld be b "o way to make sure 9 ! future t any giv5 object discov]$ 9 ! sky 0 new2 x 0 necess>y to make a complete li/ ( ev]y?+ visible 9 8 day4 ,lat] a/ronom]s ne$ !n only comp>e ,hipp>*us's catalogue ) ! heav5s f "t to "t 9 ord] to f9d out :e!r any?+ unkn[n _h appe>$4 ,?is "w ( ,hipp>*us became ! f\ndation ( sid]eal /udy1 & l$ to mo/ important discov]ies ( v>i\s k9ds4 ,b no records rema9 conc]n+ 8 new /> except ! b>e fact ( its appe>ance 9 ,scorpio4 ,hipp>*us's publi%$ works are all lo/4 ,we d n ev5 "k ! exact place ( 8 bir?1 & z = ^? two dates ( entry & exit t hi/ory atta*es to great names--we h !m n4 ,yet he 0 easily ! fir/ a/ronom] ( antiquity1 "o ( ! fir/ ( all "t2 & we "k ( him only f ! writ+s ( ,ptolemy1 :o liv$ ?ree hundr$ ye>s aft] him4 ,m ?an five c5turies elaps$ be=e ano!r tempor>y /> 0 ent]$ 9 ! records ( a/ronomy4 ,?is happ5$ 9 ! ye> #chi ,a4,d41 :5 a /> appe>$ 9 ,aquila2 & ( ?is "o also we "k no?+ fur!r4 ,b ab\t twelve c5turies lat]1 9 ,novemb]1 #aegb1 a new & brilliant object 0 f\nd 9 ! con/ellation ,cassiopeia4 ,x is kn[n z ,ty*o's />1 s9ce x 0 ! means ( w9n+ = a/ronomy a man :o w always take high rank 9 h] annals1 ,ty*o ,brahe1 ( ,d5m>k4 ,:5 he fir/ saw ?is />1 x 0 already v bright1 equall+ ev5 ,v5us at h] be/2 & he cont9u$ a c>eful s]ies ( obs]vations = sixte5 mon?s1 :5 x fad$ f9ally f 8 view4 ,! position ( ! new /> 0 measur$ ) ref]5ce to o!r />s 9 ! con/ellation ,cassiopeia1 & ! results ( ,ty*o's obs]vations 7 f9ally publi%$ by him 9 ! ye> #aegc4 ,x appe>s t mu* urg+ on ! "p ( fri5ds 0 necess>y to induce him to cons5t to ?is publication1 n because ( a mode/ reluctance to ru% into pr9t1 b = ! reason t he consid]$ x undignifi$ = a nobleman ( ,d5m>k to be ! au?or ( a book6 ,an important "q 9 cosmic a/ronomy is op5$ by ,ty*o's />4 ,did x really disappe> f ! heav5s :5 he saw x no m1 or _h its lu/re simply be5 r$uc$ bel[ ! visual p[] ( ! unaid$ eye8 ,un=tunately1 ,ty*o's obs]vations ( ! />'s position 9 ! con/ellation 7 necess>ily crude4 ,he possess$ no in/rum5ts ( precision su* z we n[ h at our disposal1 & s 8 "w gives u only a r r\gh approximation ( ! true place ( ! />4 ,a small circle might be imag9$ on ! sky ( a size comp>able ) ! possible errors ( ,ty*o's obs]vations4 ,we c\ld !n say ) c]ta9ty t 8 /> mu/ h be5 situat$ some:]e )9 t little circle1 b x is impossible to "k exactly :]e4 ,x happ5s t our mod]n telescopes reveal ! exi/5ce ( sev]al fa9t />s )9 ! space cov]$ by su* a circle4 ,any "o ( ^! w\ld h be5 too small = ,ty*o to see1 &1 !re=e1 any "o ( !m may be 8 once brilliant lum9>y r$uc$ to a /ate ( p]man5t or tempor>y semi-d>kness4 ,^! consid]ations are1 inde$1 ( great importance 9 expla9+ ! ph5om5a ( tempor>y />s4 ,if ,ty*o _h be5 able to leave u a m exact det]m9ation ( 8 />'s place 9 ! sky1 & ev5 if our mo/ p[]ful in/rum5ts c\ld n %[ any?+ 9 t place to-day1 we might nev]!less !orize on ! supposition t ! object /ill exi/s1 b has rea*$ a condition almo/ entirely d>k4 ,inde$1 ! late/ !ory classes tempor>y />s among ^? kn[n z v>iable4 ,= _m />s are kn[n to und]go q decid$ *anges 9 brilliancy2 possibly incon/ancy ( light is ! rule r ?an ! exception4 ,b :ile su* *anges1 :5 !y exi/1 are too small to be p]ceptible 9 mo/ cases1 !re is c]ta9ly a l>ge numb] ( obs]vable v>iables1 subject to easily measurable alt]ations ( light4 ,a/ronom]s pref] to see 9 ! ph5om5a ( tempor>y />s simple cases ( v>iation 9 :i* ! increase ( light is sudd51 & foll[$ by a gradual dim9ution4 ,possibly !re is !n a long p]iod ( comp>ative or ev5 complete d>kness1 to be foll[$ z be=e by a sudd5 blaz+ up & ext9ction4 ,no tempor>y />1 h[ev]1 has be5 obs]v$ to reappe> 9 ! same cele/ial place :]e once _h gl[$ its sudd5 outbur/4 ,b cases are n want+ :]e inc&esc5ce has be5 bo? prec$$ & foll[$ by a cont9u$ exi/5ce1 visible ?\gh n brilliant4 ,= su* cases z ^! x is necess>y to come d[n to mod]n records4 ,we _c be sure t "s fa9t /> has be5 tempor>ily brilliant1 unless we actually see ! conflagration itself1 or are able to make ! id5tity ( ! object's precise location 9 ! sky be=e & aft] ! ev5t p]fectly c]ta9 by ! aid ( mod]n in/rum5ts ( precision4 ,b no "o has ev] se5 ! sm\ld]+ fires break out4 ,tempor>y />s h always be5 fir/ notic$ only aft] hav+ be5 active = h\rs if n = days4 ,s we mu/ p]=ce fall back on in/rum5tal id5tification by det]m9ations ( ! />'s exact position ^u ! cele/ial vault4 ,"s "t betwe5 ,may #aj? & #ab? 9 ! ye> #ahff ! n9? /> 9 ! li/ ( kn[n tempor>ies appe>$4 ,x possess$ v great light-giv+ p[]1 be+ surpass$ 9 brilliancy by only ab\t a score ( />s 9 all ! heav5s4 ,x reta9$ a maximum lum9osity only ?ree or f\r days1 & 9 less ?an two mon?s _h dim9i%$ to a po9t some:]e betwe5 ! n9? & t5? magnitudes4 ,9 o!r words1 f a conspicu\s />1 visible to ! nak$ eye1 x _h pass$ beyond ! p[] ( any?+ less ?an a good telescope4 ,=tunately1 we _h excell5t />-catalogues be=e #ahff4 ,^! 7 at once se>*$1 & x 0 possible to settle q def9itely t a /> ( ab\t ! n9? or t5? magnitude _h really exi/$ be=e #ahff at precisely ! same po9t occupi$ by ! new "o4 ,ne$less to say1 obs]vations 7 made ( ! new /> itself1 & aft]w>d comp>$ ) lat] obs]vations ( ! fa9t "o t /ill occupies its place4 ,^! r5d] q c]ta9 ! id5tity ( ! tempor>y bright /> ) ! fa9t ones t prec$$ & foll[$ x4 ,su* results1 on ! "o h&1 (f] an excell5t v9dication ( ! pa9/ak+ labor exp5d$ on ! con/ruction ( />-catalogues1 &1 on ! o!r1 s]ve to elucidate ! my/]y ( tempor>y />s4 ,no?+ c be m plausible ?an to expla9 by analogy ^? cases 9 :i* no previ\s or subsequ5t exi/5ce has be5 obs]v$4 ,x is m]ely necess>y to suppose t1 in/ead ( v>y+ f ! n9? or t5? magnitude1 o!r tempor>y objects h begun & end$ ) ! tw5tie?2 = ! tw5tie? magnitude w\ld be beyond ! p[] ( our be/ in/rum5ts4 ,nor is ! /> ( #ahff an isolat$ in/ance4 ,t5 ye>s lat]1 9 #ahgf1 a tempor>y /> blaz$ up to ab\t ! second magnitude1 & return$ to invisibility1 s f> z ! nak$ eye is conc]n$1 )9 a mon?1 hav+ reta9$ its greate/ brilliancy only "o or two days4 ,?is /> is /ill visible z a t9y po9t ( light1 e/imat$ to be ( ! fifte5? magnitude4 ,:e!r x exi/$ prior to its sudd5 outbur/ c nev] be kn[n1 because we d n possess catalogues includ+ ! g5]ality ( />s z fa9t z ?is "o mu/ h be54 ,b at all ev5ts1 ! cont9u$ exi/5ce ( ! object helps to place ! tempor>y />s 9 ! class ( v>iables4 ,! next />1 already m5tion$ "u nebula1 0 fir/ se5 9 #ahhe4 ,x 0 9 "o respect ! mo/ rem>kable ( all1 = x appe>$ almo/ 9 ! c5tre ( ! great nebula 9 ! con/ellation ,&rom$a4 ,x 0 nev] v bright1 rea*+ only ! six? magnitude or !reab\ts1 0 obs]v$ dur+ a p]iod ( only six mon?s1 & at ! end ( t "t _h fad$ beyond ! rea* ( our mo/ p[]ful glasses4 ,x is a mo/ impressive fact t ?is ev5t occurr$ )9 ! nebula4 ,:atev] may be ! nature ( ! explosive cata/rophe to :i* ! tempor>y />s owe _! orig91 we c n[ say ) c]ta9ty t n ev5 ^? va/ elem5tal lum9\s cl\ds m5 call nebul are free f dang]4 ,! la/ outbur/ on our records 0 fir/ notic$ ,febru>y #bb1 #aija4 ,! /> appe>$ 9 ! con/ellation ,p]seus1 & soon rea*$ ! fir/ magnitude1 surpass+ almo/ e o!r /> 9 ! sky4 ,x has be5 especially rem>kable 9 t x has become surr\nd$ by a nebul\s mass 9 :i* are sev]al bright cond5sations or nuclei2 & ^! seem to be 9 v rapid motion4 ,! /> is /ill "u obs]vation 7,janu>y1 #aijb74 ,,galileo ,among ! figures t /& out %>ply ^u ! dim backgr\nd ( old-"t sci5ce1 !re is none t excites a ke5] int]e/ ?an ,galileo4 ,mo/ p "k him only z a di/+ui%$ man ( le>n+2 "o :o c>ri$ on a vigor\s controv]sy ) ! ,*ur* on matt]s sci5tific4 ,x requires "s little /udy1 "s c>eful read+ betwe5 ! l9es ( a/ronomical hi/ory1 to ga9 acqua9tance ) ! man himself4 ,he _h a brilliant1 incisive wit2 0 a g5u9e humori/2 knew well & lov$ ! amus+ side ( ?+s2 & c\ld n (t5 =ego a s>ca/ic pleasantry1 or d5y himself ! pleasure ( argum5t4 ,yet x is m ?an d\btful if he ev] int5d$ imp]t95ce1 or gave will+ly any cause ( qu>rel to ! ,*ur*4 ,8 acute und]/&+ mu/ h se5 t !re exi/s no real conflict betwe5 sci5ce & religion2 = "t1 9 pass+1 has made common k ( ?is tru?1 z x has ( _m ?+s once hidd54 ,:5 we consid] ev5ts t occurr$ ?ree c5turies ago1 x is easy to replace excit$ argum5t ) cool judgm5t2 to rememb] t ^? 7 days ( viol5ce & cruelty2 t public ignorance 0 ( a d5sity difficult to imag9e to-day2 & t x 0 univ]sally consid]$ ! duty ( ! ,*ur* to assume an au?oritative attitude ^u _m que/ions ) :i* %e is n n[ requir$ to conc]n h]self 9 ! lea/4 ,*>latans1 unbalanc$ !ori/s1 purveyors ( sci5tific m>vels1 7 all liable to be pass$ ^u def9itely by ! ,*ur*1 n 9 a _s ( imp]t95t int]f]5ce1 b simply z "p ( h] regul> duties4 ,if ! ,*ur*'s judgm5t 9 su* matt]s 0 sometimes errone\s2 if h] int]f]5ce n[ & aga9 0 cruel1 ! cause mu/ be s\ght 9 ! mann]s & cu/oms ( ! "t1 :5 p]secution riot$ 9 company ) ignorance1 & viol5ce 0 ! law4 ,p]haps ev5 to-day x w\ld n be amiss to h a mod]n sci5tific bo>d pass au?oritatively ^u novel discov]ies & inv5tions1 s z to protect ! public aga9/ impo/ors z ! ,*ur* tri$ to d ( old4 ,galileo 0 born at ,pisa 9 #aefd1 & 8 long life la/$ until #afdb1 ! v ye> ( ,newton's bir?4 ,8 mo/ important sci5tific discov]ies may be summ$ up 9 a few words2 he 0 ! fir/ to use a telescope = exam9+ ! heav5ly bodies2 he discov]$ m\nta9s on ! moon2 ! satellites ( ,jupit]2 ! peculi> appe>ance ( ,saturn :i* ,huyg5s aft]w>d expla9$ z a r+ surr\nd+ ! ball ( ! planet2 &1 f9ally1 he f\nd black spots on ! sun's disk4 ,^! discov]ies1 toge!r ) 8 rem>kable rese>*es 9 me*anical sci5ce1 con/itute ,galileo's claim to immortality z an inve/igator4 ,b1 z we h said1 x is n our int5tion to consid] 8 "w z a s]ies ( sci5tific discov]ies4 ,we %all take a m int]e/+ po9t ( view1 & deal ) him r z a human be+ :o _h contract$ ! habit ( mak+ sci5tific rese>*es4 ,:at mu/ h be5 8 feel+s :5 he fir/ f\nd ) 8 new telescope ! satellites ( ,jupit]8 ,!y 7 se5 on ! night ( ,janu>y #g1 #afaj4 ,he _h already view$ ! planet ?r\gh 8 e>li] & less p[]ful glass1 & 0 aw>e t x possess$ a r\nd disk l ! moon1 only small]4 ,n[ he saw also ?ree objects t he took to be little />s ne> ! planet4 ,b on ! foll[+ night1 z he says1 drawn by :at fate ,i "k n1 ! tube 0 aga9 turn$ ^u ! planet4 ,! ?ree small />s _h *ang$ _! positions1 & 7 n[ all situat$ to ! we/ ( ,jupit]1 :]eas on ! previ\s night two _h be5 on ! ea/]n side4 ,he c\ld n expla9 ?is ph5om5on1 b he recogniz$ t !re 0 some?+ peculi> at "w4 ,long aft]w>d1 9 "o ( 8 lat] works1 translat$ into qua9t old ,engli% by ,salusbury1 he decl>$ t "o sole exp]im5t suffice? to batt] to ! gr\nd a ?\s& probable ,argum5ts4 ,?is 0 already ! guid+ pr9ciple ( 8 sci5tific activity1 a pr9ciple ( incomp>able importance1 & g5]ally cr$it$ to ,bacon4 ,ne$less to say1 ,jupit] 0 n[ exam9$ e night4 ,! #i? 0 cl\dy1 b on ! #aj? he aga9 saw 8 little />s1 _! numb] n[ r$uc$ to two4 ,he guess$ t ! ?ird 0 beh9d ! planet's disk4 ,! position ( ! two visible ones 0 altoge!r diff]5t f ei!r ( ! previ\s obs]vations4 ,on ! #aa? he became sure t :at he saw 0 really a s]ies ( satellites accompany+ ,jupit] on 8 j\rney ?r\gh space1 & at ! same "t revolv+ ar\nd him4 ,on ! #ab?1 at #c ,a4,m41 he actually saw "o ( ! small objects em]ge f beh9d ! planet2 & on ! #ac? he f9ally saw f\r satellites4 ,two hundr$ & eighty-two ye>s 7 de/9$ to pass away be=e any human eye %\ld see a fif?4 ,x 0 ,b>n>d 9 #ahib :o foll[$ ,galileo4 ,to und]/& ! effect ( ?is discov]y ^u ,galileo requires a p]son :o has himself wat*$ ! />s1 n1 z a dilettante1 seek+ recreation or amusem5t1 b ) t deep rev]5ce t comes only to him :o feels--nay1 kn[s--t 9 ! mom5t ( obs]vation j pass$ he too has add$ 8 mite to ! great fund ( human k4 ,galileo's mummi$ =ef+] /ill po9ts t[>d ! />s f its little p$e/al ( wood 9 ! ,museo at ,flor5ce1 a sign to all m5 t he is un=gott54 ,b ,galileo knew on t #aa? ( ,janu>y1 #afaj1 t ! memory ( him w\ld nev] fade2 t ! v music ( ! sph]es w\ld !nce=w>d be attun$ to a tru] note1 if any w\ld b he>k5 to ! ,jovian h>mony4 ,= he recogniz$ at once t ! visible revolution ( ^! moons ar\nd ,jupit]1 :ile t planet 0 himself visibly travell+ ?r\gh space1 mu/ deal its dea?-bl[ to ! old ,ptolemaic sy/em ( ! univ]se4 ,"h 0 a great planet1 ! c5tre ( a sy/em ( satellites1 & yet n ! c5tre ( ! univ]se4 ,surely1 !n1 ! e>?1 too1 might be a m]e planet l ,jupit]1 & n ! suppos$ motionless c5tre ( all ?+s4 ,! satellite discov]y 0 publi%$ 9 #afaj 9 a little book call$ ,sid]eus ,nuncius1 usually translat$ ,! ,sid]eal ,mess5g]4 ,x seems to u1 h[ev]1 t ! ^w mess5g] is n /rong en\gh2 surely 9 ,papal ,italy a nuncius 0 m ?an a m]e mess5g]4 ,he 0 clo!d ) ! v highe/ au?ority1 & we ?9k x probable t ,galileo's *oice ( ?is ^w 9 ! title ( 8 book means t he claim$ = himself simil> au?ority 9 sci5ce4 ,at all ev5ts1 ! book made him at once a great reputation & num]\s enemies4 ,b x 0 n until #afaf t ! ,holy ,(fice 7,inquisition7 issu$ an edict ord]+ ,galileo to ab&on 8 op9ion t ! e>? mov$1 & at ! same "t plac$ ,cop]nicus's ,de ,revolutionibus & two o!r books advocat+ t doctr9e on ! ,index ,librorum ,prohibitorum1 or li/ ( books =bidd5 by ! ,*ur*4 ,^! volumes rema9$ 9 subsequ5t editions ( ! ,index d[n to #ahba1 b !y no long] appe> 9 ! edition 9 =ce to-day4 ,galileo's mo/ *>act]i/ic "w is entitl$ ! ,dialogue on ! ,two ,*ief ,sy/ems ( ! ,_w4 ,x 0 n publi%$ until #afcb1 al?\gh ! idea ( ! book 0 conceiv$ _m ye>s e>li]4 ,9 x he gave full play to 8 extraord9>y p[]s z a true humori/1 a f9e lame among controv]siali/s1 & a g5u9e man ( sci5ce1 valu+ nak$ tru? above all o!r ?+s4 ,z may be imag9$1 x 0 no small matt] to obta9 ! au?orities' cons5t to ?is publication4 ,galileo 0 already kn[n to hold h]etical op9ions1 & x 0 suspect$ t he _h n laid !m aside :5 comm&$ to d s by ! edict ( #afaf4 ,b p]haps ,galileo's introduction to ! ,dialogue secur$ ! c5sor's imprimatur2 x is ev5 suspect$ t ! ,roman au?orities help$ 9 ! prep>ation ( ?is introduction4 ,=tunately1 we h a delightful contempor>y translation into ,engli%1 by ,?omas ,salusbury1 pr9t$ at ,london by ,leyb\rne 9 #affa4 ,we h already quot$ f ?is translation1 & n[ add f ! same "w "p ( ,galileo's ma/]ly preface to ! ,dialogue3 ,judici\s read]1 !re 0 publi%$ "s ye>s s9ce 9 ,rome a salutif]\s ,edict1 t1 = ! obviat+ ( ! dang]\s ,sc&als ( ! ,pres5t ,age1 impos$ a reasonable ,sil5ce ^u ! ,py?agorean 7,cop]nican7 op9ion ( ! ,mobility ( ! ,e>?4 ,!re want n su* z unadvis$ly affirm1 t ! ,decree 0 n ! production ( a sob] ,scrut9y1 b ( an ill-=m$ passion2 & "o may he> "s mutt] t ,consultors altoge!r ignorant ( ,a/ronomical obs]vations ought n to clipp ! w+s ( speculative wits ) ra% prohibitions4 ,galileo fir/ /ates 8 own views1 & !n pret5ds t he w oppose !m4 ,he goes on to say t he believes 9 ! e>?'s immobility1 & takes ! contr>y only = a ma!matical ,capriccio1 z he calls x2 some?+ to be consid]$1 because possess+ an academical int]e/1 b on no acc\nt hav+ a real exi/5ce4 ,( c\rse any "o 7ev5 a c5sor7 ought to be able to see t x is ! ,capriccio1 & n its opposite1 t ,galileo really advocates4 ,?ree p]sons appe> 9 ! ,dialogue3 ,salviati1 :o believes 9 ! ,cop]nican sy/em2 ,simplicio1 ( sugge/ive "n1 :o ?9ks ! e>? _c move2 &1 f9ally1 ,sagr$us1 a neutral g5tleman ( humor\s prop5sities1 :o usually beg9s by oppos+ ,salviati1 b ends by be+ conv9c$4 ,he !n helps to puni% poor ,simplicio1 :o is "o ( ^? p]sons app>5tly incapable ( compreh5d+ a reasonable argum5t4 ,"h is an int]e/+ specim5 ( ! ,dialogue tak5 f ,salusbury's translation3 ,salviati ref]s to ! argum5t1 !n well kn[n1 t ! e>? _c rotate on its axis1 because ( ! impossibility ( its mov+ long )\t we>9esse4 ,sagr$us replies3 ,!re are "s k9ds ( animals :i* refre% !mselves aft] we>9esse by r[l+ on ! e>?2 & t !re=e !re is no ne$ to fe> t ! ,t]re/rial ,globe %\ld tire1 nay1 x may be reasonably affirm$ t x enjoye? a p]petual & mo/ tranquil repose1 keep+ itself 9 an et]nal r[l+4 ,salviati's comm5t on ?is sally is1 ,y are too t>t & satyrical1 ,sagr$us4 ,!re is no d\bt t ! ,dialogue f9i%$ ! ,ptolemaic !ory1 & made t ( ,cop]nicus ! only possible "o4 ,at all ev5ts1 x br\ght ab\t ! well-kn[n attack ^u ,galileo f ! au?orities ( ! ,holy ,(fice4 ,we %all n rec\nt ! (t5-told tale ( 8 recantation4 ,he 0 convict$ 7v rightly7 ( be+ a ,cop]nican1 & 0 =c$ to abjure t doctr9e4 ,galileo's life may be summ$ up z "o ( ^? ?r\gh :i* ! _w has be5 made ri*]4 ,a clean-cutt+ analytic wit1 nev] becom+ dull3 heat$ aga9 & aga9 9 ! fi]ce blaze ( controv]sy1 x 0 all[$ to cool only t x might acquire a f9] temp]1 to pi]ce ) fatal c]ta9ty ! smalle/ imp]fections 9 ! armor ( 8 adv]s>ies4 ,,! ,,planet ,,( #ahih ,! discov]y ( a new & important planet usually receives m imm$iate popul> att5tion & applause ?an any o!r a/ronomical ev5t4 ,philosoph]s are fond ( ref]r+ to our sol> sy/em z a m]e atom among ! c\ntless univ]ses t seem to be susp5d$ )9 ! pr(\nd dep?s ( space4 ,!y are wont to po9t out t ?is sol> sy/em1 small & insignificant z a :ole 9 comp>ison ) _m ( ! /ell> worlds1 is1 nev]!less1 made up ( a l>ge numb] ( con/itu5t planets2 & ^! 9 turn are (t5 accompani$ ) /ill small] satellites1 or moons4 ,?us does ,nature provide worlds )9 worlds1 & x is n surpris+ t public att5tion %\ld be at once attract$ by any new memb] ( our sun's own special family ( planets4 ,! anci5ts 7 acqua9t$ ) only five ( ! bodies n[ c\nt$ z planets1 viz43 ,m]cury1 ,v5us1 ,m>s1 ,jupit]1 & ,saturn4 ,! dates ( _! discov]y are lo/ 9 antiquity4 ,to ^! ,uranus 0 add$ 9 #agha by a brilliant ef=t ( ! eld] ,h]s*el4 ,we are told t int5se popul> excitem5t foll[$ ! ann\ncem5t ( ,h]s*el's fir/ obs]vation3 he 0 knight$ & o!rwise honor$ by ! ,engli% ,k+1 & 0 enabl$ to lay a secure f\ndation = ! future di/+ui%$ a/ronomical reputation ( 8 family4 ,h]s*el's discov]y quick5$ ! re/less activity ( a/ronom]s4 ,p]si/5t ef=ts 7 made to sift ! heav5s m & m closely1 ) ! /r5g!n$ hope ( add+ /ill fur!r to our planet>y k4 ,an association ( tw5ty-f\r en?usia/ic ,g]man a/ronom]s 0 =m$ = ! express purpose ( hunt+ planets4 ,b x fell to ! lot ( an ,italian1 ,piazzi1 ( ,pal]mo1 to f9d ! fir/ ( t s]ies ( small bodies n[ kn[n z ! a/]oids or m9or planets4 ,he made ! discov]y at ! v beg9n+ ( our c5tury1 ,janu>y #a1 #ahja4 ,b news travell$ sl[ly 9 ^? days1 & x 0 n until ne>ly ,april t ! ,g]man obs]v]s he>d f ,piazzi4 ,9 ! meantime1 he _h himself be5 prev5t$ by illness f cont9u+ 8 obs]vations4 ,un=tunately1 ! planet _h by ?is "t mov$ s ne> ! sun1 on acc\nt ( its own motions & ^? ( ! e>?1 t x c\ld no long] be obs]v$4 ,! bright light ( ! sun made obs]vations ( ! new body impossible2 & x 0 fe>$ t1 ow+ to lack ( k ( ! planet's orbit1 a/ronom]s w\ld be unable to trace x4 ,s !re seem$1 inde$1 to be dang] ( an almo/ irrep>able loss to sci5ce4 ,b 9 sci5tific1 z 9 o!r human em]g5cies1 someone always appe>s at ! prop] mom5t4 ,a v "y ma!matician at ,gtt+51 nam$ ,gauss1 attack$ ! problem1 & 0 able to devise a me?od ( pr$ict+ ! future c\rse ( ! planet on ! sky1 us+ only ! few obs]vations made by ,piazzi himself4 ,up to t "t no "o _h attempt$ to compute a planet>y orbit1 unless he _h at 8 disposal a s]ies ( obs]vations ext5d+ ?r\gh\t ! :ole p]iod ( ! planet's revolution ar\nd ! sun4 ,b ! ,piazzi planet (f]$ a new problem 9 a/ronomy4 ,x _h become imp]atively necess>y to obta9 an orbit f a few obs]vations made at ne>ly ! same date4 ,gauss's "w 0 signally triumphant1 = ! planet 0 actually f\nd 9 ! position pr$ict$ by him1 z soon z a *ange 9 ! relative places ( ! planet & e>? p]mitt$ suitable obs]vations to be made4 ,b aft] all1 ,piazzi's planet belongs to a class ( q small bodies1 & is by no means z int]e/+ z ,h]s*el's discov]y1 ,uranus4 ,yet ev5 ?is mu/ be relegat$ to second rank among planet>y discov]ies4 ,on ,septemb] #bc1 #ahdf1 ! telescope ( ! ,b]l9 ,obs]vatory 0 direct$ to a c]ta9 po9t on ! sky = a v special reason4 ,galle1 ! a/ronom] ( ,b]l91 _h receiv$ a lett] f ,lev]ri]1 ( ,p>is1 tell+ him t if he w\ld look 9 a c]ta9 direction he w\ld detect a new & l>ge planet4 ,lev]ri]'s in=mation 0 bas$ ^u a ma!matical calculation4 ,seat$ 9 8 /udy1 ) no in/rum5ts b p5 & pap]1 he _h sl[ly figur$ out ! hi/ory ( a _w z yet unse54 ,t9y discrepancies exi/$ 9 ! obs]v$ motions ( ,h]s*el's planet ,uranus4 ,no man _h expla9$ _! cause4 ,to ,lev]ri]'s acute und]/&+ !y sl[ly %ap$ !mselves into ! possible effects ( attraction emanat+ f "s unkn[n planet ext]ior to ,uranus4 ,0 x conceivable t ^! slight tremul\s imp]fections 9 ! motion ( a planet c\ld be expla9$ 9 ?is way8 ,lev]ri] 0 able to say confid5tly1 ,yes4 ,b we may re/ assur$ t ,galle _h b small hopes t ^u 8 eye fir/1 ( all ! myriad eyes ( m51 w\ld fall a ray ( ! new planet's light4 ,c>eful & me?odical1 he w\ld neglect no *ance ( advanc+ 8 belov$ sci5ce4 ,he w\ld look4 ,only "o :o has himself (t5 se5 ! morn+'s sunrise put an end to a night's obs]vation ( ! />s c hope to appreciate :at ,galle's feel+s mu/ h be5 :5 he saw ! planet4 ,to 8 tra9$ eye x 0 c]ta9ly recognizable at once4 ,& !n ! good news 0 s5t on to ,p>is4 ,we c imag9e ,lev]ri]1 ! cool calculator1 say+ to himself3 ,( c\rse he f\nd x4 ,x 0 a ma!matical c]ta9ty4 ,nev]!less1 8 satisfaction mu/ h be5 ( ! ke5e/4 ,no triumphs give a pleasure high] ?an ^? ( ! intellect4 ,let no "o imag9e t m5 :o make rese>*es 9 ! doma9 ( pure sci5ce are "u-paid4 ,!y f9d _! rew>d 9 pleasure t is beyond any price4 ,! ,lev]ri] planet 0 f\nd to be ! la/ ( ! s-call$ major planets1 s f> z we c say 9 ! pres5t /ate ( sci5ce4 ,x receiv$ ! "n ,neptune4 ,obs]v]s h f\nd no o!r memb] ( ! sol> sy/em comp>able 9 size ) su* bodies z ,uranus & ,neptune4 ,m ?an "o eag] ma!matician has tri$ to repeat ,lev]ri]'s a*ievem5t1 b ! suppos$ planet 0 n f\nd4 ,x has be5 said t figures nev] lie2 yet su* is ! case only :5 ! computations are correctly made4 ,p are prone to give to ! "w ( c>eless or incompet5t ma!maticians ! same degree ( cr$5ce t is really due only to ma/]s ( ! craft4 ,x requires ! te/ ( "t to affix to any man's "w ! /amp ( true g5ius4 ,:ile1 !n1 we h f\nd no m l>ge planets1 q a gr\p ( companions to ,piazzi's little "o h be5 discov]$4 ,!y are all small1 probably nev] exce$+ ab\t #djj miles 9 diamet]4 ,all travel ar\nd ! sun 9 orbits t lie :olly )9 t ( ,jupit] & are ext]ior to t ( ,m>s4 ,! introduction ( a/ronomical photography has giv5 a trem5d\s impetus to ! discov]y ( ^! m9or planets1 z !y are call$4 ,x is q int]e/+ to exam9e ! photographic process by :i* su* discov]ies are made possible & ev5 easy4 ,! matt] w n be difficult to und]/& if we rememb] t all ! planets are cont9ually *ang+ _! places among ! o!r />s4 ,= ! planets travel ar\nd ! sun at a comp>atively small di/ance4 ,! great majority ( ! />s1 on ! contr>y1 are sep>at$ f ! sun by an almo/ immeasurable space4 ,z a result1 !y d n seem to move at all among !mselves1 & s we call !m fix$ />s3 !y may1 inde$1 be 9 motion1 b _! great di/ance prev5ts our detect+ x 9 a %ort p]iod ( "t4 ,n[1 /ell> photographs are made 9 mu* ! same way z ord9>y portraits4 ,only1 in/ead ( us+ a simple cam]a1 ! a/ronom] exposes 8 photographic plate at ! eye-end ( a telescope4 ,! s5sitive surface ( ! plate is sub/itut$ = ! human eye4 ,we !n f9d on ! picture a little dot correspond+ to e /> )9 ! photograph$ region ( ! sky4 ,b1 z ev]yone kn[s1 ! turn+ ( ! e>? on its axis makes ! :ole heav5s1 includ+ ! sun1 moon1 & />s1 rise & set e day4 ,s ! />s1 :5 we photograph !m1 are sure to be ei!r climb+ up 9 ! ea/]n sky or else sl[ly creep+ d[n 9 ! we/]n4 ,& t makes a/ronomical photography v diff]5t f ord9>y portrait "w4 ,! />s correspond to ! sitt]1 b !y don't sit /ill4 ,= ?is reason x is necess>y to connect ! telescope ) a me*anical contrivance :i* makes x turn r\nd l ! h\r-h& ( an ord9>y clock4 ,! arrangem5t is s adju/$ t ! telescope1 once aim$ at ! prop] object 9 ! sky1 w move s z to rema9 po9t$ exactly ! same dur+ ! :ole "t ( ! photographic exposure4 ,?us1 :ile ! light ( any /> is act+ on ! plate1 su* action w be cont9u\s at a s+le po9t4 ,consequ5tly1 ! f9i%$ picture w %[ ! /> z a little dot2 :ile )\t ?is arrangem5t1 ! /> w\ld trail out into a l9e in/ead ( a dot4 ,n[ we h se5 t ! planets are all mov+ sl[ly among ! fix$ />s4 ,s if we make a /> photograph 9 a "p ( ! sky :]e a planet happ5s to be1 ! planet w make a %ort l9e on ! plate2 :]eas1 if ! planet rema9$ q unmov$ relatively to ! />s x w\ld give a dot l ! /> dots4 ,! pres5ce ( a l9e1 !re=e1 at once indicates a planet4 ,?is me?od ( planet-hunt+ has prov$ mo/ useful4 ,m ?an #djj small planets simil> to ,piazzi's h be5 f\nd1 ?\gh nev] ano!r "o l ,uranus & ,neptune4 ,z we h said1 all ^! little bodies lie betwe5 ,m>s & ,jupit]4 ,!y evid5tly belong to a gr\p or family1 & _m a/ronom]s h be5 l$ to believe t !y are b fragm5ts ( a =m] l>ge planet4 ,9 ,augu/1 #ahih1 h[ev]1 "o 0 f\nd by ,witt1 ( ,b]l91 :i* w probably occupy a v prom95t place 9 ! annals ( a/ronomy4 ,= ?is planet goes well )9 ! orbit ( ,m>s1 & ?is w br+ x at times v close to ! e>?4 ,9 fact1 :5 ! motions ( ! new planet & ! e>? comb9e to br+ !m to _! positions ( greate/ proximity1 ! new planet w approa* u clos] ?an any o!r cele/ial body except our own moon4 ,witt nam$ 8 new planet ,eros4 ,its size1 ?\gh small1 may prove to be suffici5t to br+ x )9 ! possibilities ( nak$-eye obs]vation at ! "t ( close/ approa* to ! e>?4 ,to a/ronom]s ! great importance ( ?is new planet is due to ! foll[+ circum/ance3 ,= c]ta9 reasons too te*nical to be /at$ "h 9 detail1 ! di/ance f ! e>? to any planet c be det]m9$ ) a degree ( precision :i* is greate/ = planets t are ne> u4 ,?us 9 "t we %all le>n ! di/ance ( ,eros m accurately ?an we "k any o!r cele/ial di/ance4 ,f ?is1 by a process ( calculation1 ! sol> di/ance f ! e>? is det]m9able4 ,b ! di/ance f e>? to sun is ! fundam5tal a/ronomical unit ( measure2 s t ,witt's discov]y1 ?r\gh its effect on ! unit ( measure1 w d\btless influ5ce e "p ( ! sci5ce ( a/ronomy4 ,"h we h once m a /rik+ in/ance ( ! rew>d sure to ov]take ! dilig5t work] 9 sci5ce--a :ole g5]ation ( m5 w d\btless pass away be=e we %all h exhau/$ ! sci5tific advantages to be drawn f ,witt's rem>kable obs]vation ( #ahih4 ,,h[ ,,to ,,make ,a ,,sun-,,dial,a ,long be=e clocks & wat*es _h be5 inv5t$1 p began to measure "t ) sun-dials4 ,n[adays1 :5 almo/ ev]yone has a wat* 9 8 pocket1 & c h a clock1 too1 on ! mantel-piece ( e room 9 ! h\se1 ! sun-dial has ceas$ to be ne$$ 9 ord9>y life4 ,b x is /ill j z int]e/+ z ev] to anyone :o w\ld l to h ! means ( gett+ "t direct f ! sun1 ! great h\r-h& or timekeep] ( ! sky4 ,any p]son :o is h&y ) tools c make a sun-dial q easily1 by foll[+ ! directions giv5 bel[4 ,9 ! fir/ place1 y mu/ "k t ! sun-dial gives ! "t by means ( ! sun's %ad[4 ,if y /ick a walk+-cane up 9 ! s& on a bright1 sun%9y day1 ! cane has a long %ad[ t looks l a d>k l9e on ! gr\nd4 ,n[ if y wat* ?is %ad[ c>efully1 y w see t x does n /ay 9 ! same place all day4 ,sl[ly b surely1 z ! sun climbs up 9 ! sky1 ! %ad[ creeps ar\nd ! cane4 ,y c see q easily t if ! cane 7 fa/5$ 9 a bo>d floor1 & if we c\ld m>k on ! floor ! places :]e ! %ad[ 0 at diff]5t h\rs ( ! day1 we c\ld make ! %ad[ tell u ! "t j l ! h\r-h& ( a clock4 ,a sun-dial is j su* an arrangem5t z ?is1 & ,i w %[ y h[ to m>k ! %ad[ places exactly1 s z to tell ! "r "t )\t any tr\ble :5ev] ! sun %9es4 ,if y 7 to wat* v c>efully su* an arrangem5t z a cane /&+ 9 a bo>d floor1 y w\ld n f9d ! creep+ %ad[ 9 j ! same place at ! same "t e day4 ,if y m>k$ ! place ( ! %ad[ at exactly t5 o'clock by y\r wat* "s morn+1 & !n w5t back ano!r day at t51 y w\ld n f9d ! %ad[ on ! old m>k4 ,x w\ld n get v f> f x 9 a day or two1 b 9 a mon? or s x w\ld be q a di/ance away4 ,n[1 ( c\rse1 a sun-dial w\ld be ( no use if x did n tell ! "t correctly e day2 & 9 fact1 x is n easy to make a dial :5 ! %ad[ is ca/ by a /ick /&+ /raight up4 ,b we c get ov] ?is difficulty v well by lett+ ! %ad[ be ca/ by a /ick t leans ov] t[>d ! floor j ! "r am\nt1 z ,i w expla9 9 a mom5t4 ,( c\rse1 we %\ld n really use ! floor = our sun-dial4 ,x is mu* bett] to m>k out ! h\r-l9es1 z !y are call$1 on a smoo? piece ( ord9>y :ite bo>d1 & !n1 aft] ! dial is f9i%$1 x c be screw$ d[n to a piazza floor or rail+1 or x c be fa/5$ on a w9d[-sill4 ,x ought to be put 9 a place :]e ! sun c get at x mo/ ( ! "t1 because1 ( c\rse1 y _c use ! sun-dial :5 ! sun is n %9+ on x4 ,if ! dial is set on a w9d[-sill 7( a city h\se1 = in/ance7 y mu/ *oose a s\? w9d[ if y c1 s z to get ! sun ne>ly all day4 ,if y h to take an ea/ w9d[1 y c use ! dial 9 ! morn+ only1 & 9 a we/ w9d[ only 9 ! aft]noon4 ,sometimes x is be/ n to try to fa/5 ! dial to its support ) screws1 b j to m>k its place1 & !n set x out :5ev] y want to use x4 ,= if ! dial is made ( wood1 & n pa9t$1 x might be injur$ by ra9 or sn[ 9 bad wea!r if left out on a w9d[-sill or piazza4 ,illu/ration3 ,fig4 #a4 ,x is n q easy to fa/5 a little /ick to a bo>d s t x w lean ov] j "r4 ,s x is bett] n to use a /ick or a cane 9 ! way ,i h describ$1 b in/ead to use a piece ( bo>d cut to j ! "r %ape4 ,fig4 #a %[s :at a sun-dial %\ld look l4 ,! l9es to %[ ! %ad['s place at ! diff]5t h\rs ( ! day w be m>k$ on ! bo>d ,,abcd1 & ?is w be put flat on ! w9d[-sill or piazza floor4 ,! ?ree-corn]$ piece ( bo>d abc is fa/5$ to ! bottom-bo>d ,,abcd by screws go+ ?r\gh ,,abcd f und]nea?4 ,! edge ab ( ! ?ree-corn]$ bo>d abc !n takes ! place ( ! lean+ /ick or cane1 & ! "t is m>k$ by ! %ad[ ca/ by ! edge ab4 ,( c\rse1 x is important t ?is edge %\ld be /raight & p]fectly flat & ev54 ,if y are h&y ) tools1 y c make x q easily1 b if n1 y c m>k ! "r %ape on a piece ( pap] v c>efully1 & take x to a c>p5t]1 :o c cut ! bo>d accord+ to ! patt]n y h m>k$ on ! pap]4 ,illu/ration3 ,fig4 #b4 ,n[ ,i mu/ tell y h[ to draw ! %ape ( ! ?ree-corn]$ bo>d abc4 ,fig4 #b %[s h[ x is done4 ,! side ac %\ld always be j five in*es long4 ,! side bc is drawn at "r angles to ac1 :i* y c d ) an ord9>y c>p5t]'s squ>e4 ,! l5g? ( bc dep5ds on ! place = :i* ! dial is made4 ,! foll[+ table gives ! l5g? ( bc = v>i\s places 9 ! ,unit$ ,/ates1 &1 aft] y h m>k$ out ! l5g? ( bc1 x is only necess>y to complete ! ?ree-corn]$ piece by draw+ ! side ab f a to b4 ,,table ,,%[+ ,,! ,,l5g? ,,( ,,! ,,side bc4 -------------------------- ,place4 b c ,in*es4 -------------------------- ,albany #d-aa_/af ,baltimore #d-a_/af ,bo/on #d-a_/b ,buffalo #d-aa_/af ,*>le/on #c-a_/d ,*icago #d-a_/b ,c9c9nati #d-a_/af ,clevel& #d-a_/b ,d5v] #d-c_/af ,detroit #d-a_/b ,indianapolis #d-a_/af ,kansas ,city #c-ae_/af ,l\isville #c-ae_/af ,milwaukee #c-aa_/af ,new ,orleans #b-g_/h ,new ,york #d-c_/h ,omaha #d-c_/h ,philadelphia #d-c_/af ,pittsburg #d-c_/h ,portl&1 ,me #d-ac_/af ,ri*mond #c-ae_/af ,ro*e/] #d-aa_/af ,san ,diego #c-a_/d ,san ,francisco #c-ae_/af ,savannah #c-a_/h ,/4 ,l\is #c-ae_/af ,/4 ,paul #e ,seattle #e-i_/af ,wa%+ton1 ,d4 ,c4 #d-a_/af -------------------------- ,if y wi% to make a dial = a place n giv5 9 ! table1 x w be ne> en\gh to use ! di/ance bc z giv5 = ! place ne>e/ to y4 ,b 9 select+ ! ne>e/ place f ! table1 please rememb] to take t "o ( ! cities m5tion$ :i* is ne>e/ to y 9 a nor?-&-s\? direction4 ,x does n matt] h[ f> away ! place is 9 an ea/-&-we/ direction4 ,s1 in/ead ( tak+ ! place t is ne>e/ to y on ! map 9 a /raight l9e1 take ! place to :i* y c\ld travel by go+ pr9cipally ea/ or we/1 & v little nor? or s\?4 ,! figure drawn is ab\t ! "r %ape = ,new ,york4 ,! bo>d us$ = ! ?ree-corn]$ piece %\ld be ab\t "o-half in* ?ick4 ,b if y are mak+ a w9d[-sill dial1 y may pref] to h x small] ?an ,i h describ$4 ,y c easily h x half z big by mak+ all ! sizes & l9es 9 half-in*es :]e ! table calls = in*es4 ,aft] y h m>k$ out ! dim5sions = ! ?ree-corn]$ piece t is to ?r[ ! %ad[1 y c prep>e ! dial itself1 ) ! l9es t m>k ! place ( ! %ad[ = e h\r ( ! day4 ,?is y c d 9 ! mann] %[n 9 ,fig4 #c4 ,j z 9 ! case ( ! ?ree-corn]$ piece1 y c draw ! dial ) a p5cil directly on a smoo? piece ( :ite bo>d1 ab\t ?ree-qu>t]s ( an in* ?ick1 or y c m>k x out on a pap] patt]n & transf] x aft]w>d to ! bo>d4 ,p]haps x w be z well to beg9 by draw+ on pap]1 z any mi/akes c !n be correct$ be=e y comm5ce to m>k y\r wood4 ,illu/ration3 ,fig4 #c4 ,9 ! fir/ place y mu/ draw a c\ple ( l9es ,,mn & ,m,n1 eight in*es long1 & j f> en\gh ap>t to fit ! edge ( y\r ?ree-corn]$ %ad[-piece4 ,y w rememb] ,i told y to make t "o-half in* ?ick1 s y\r two l9es w also be "o-half in* ap>t4 ,n[ draw ! two l9es ,,no & ,n,o squ>e ) ,,mn & ,m,n1 & make ! di/ances ,,no & ,n,o j five in*es ea*4 ,! l9es ,,ok1 ,o,k1 & ! o!r l9es =m+ ! out] bord] ( ! dial1 are !n drawn j z %[n1 ,,ok & ,o,k be+ j eight in*es long1 ! same z ,,mn & ,m,n4 ,! l[] l9es 9 ! figure1 :i* are n v important1 are to complete ! squ>es4 ,y mu/ m>k ! l9es ,,no & ,n,o ) ! figures ,,vi1 ^! be+ ! l9es rea*$ by ! %ad[ at six o'clock 9 ! morn+ & ev5+4 ,! po9ts :]e ! ,,vii1 ,,viii1 & o!r h\r-l9es cut ! l9es ,,ok1 ,o,k1 ,,mk1 & ,m,k c be f\nd f ! table on page #gh4 ,9 us+ ! table y w notice t ! l9e ,,ix falls sometimes on "o side ( ! corn] ,k1 & sometimes on ! o!r4 ,?us = ,albany ! l9e passes sev5 & sev5-sixte5? in*es f ,o1 :ile = ,*>le/on x passes f\r & ?ree-eigh? in*es f ,m4 ,= ,baltimore x passes exactly ?r\gh ! corn] ,k4 ,,table ,,%[+ ,,h[ ,,to ,,m>k ,,! ,,h\r-,,l9es4 ---------------------------------------- ------------------------------ ,di/ance f ,o to ! l9e ,di/ance f ,m to ! m>k$ l9e m>k$ ,,place4 ---------------------------------------- --------- ,,vii4 ,,viii4 ,,ix4 ,,ix4 ,x4 ,,xi4 ---------------------------------------- -------------------------- ,in*es4 ,in*es4 ,in*es4 ,in*es4,in*es4 ,in*es4 ,albany #a-ae_/af #d-c_/af #g-g_/af #c-a_/af #a-g_/af ,baltimore #b-a_/h #d-aa_/af #h #b-g_/h #a-g_/af ,bo/on #b #d-e_/af #g-g_/af #c-a_/af #a-g_/af ,buffalo #a-ae_/af #d-c_/af #g-g_/af #c-a_/af #a-g_/af ,*>le/on #b-g_/af #e-c_/h #d-c_/h #b-a_/b #a-a_/h ,*icago #b #d-e_/af #g-g_/af #c-a_/af #a-g_/af ,c9c9nati #b-a_/h #d-aa_/af #h #b-g_/h #a-g_/af ,clevel& #b #d-e_/af #g-g_/af -- #c-a_/af #a-g_/af ,d5v] #b-a_/h #d-a_/b #g-aa_/af #b-g_/h #a-g_/af ,detroit #b #d-e_/af #g-g_/af #c-a_/af #a-g_/af ,indianapolis #b-a_/h #d-aa_/af #h #b-g_/h #a-g_/af ,kansas ,city #b-a_/d #d-aa_/af #h #b-g_/h #a-e_/af ,l\isville #b-a_/d #d-aa_/af #h #b-g_/h #a-e_/af ,milwaukee #a-ae_/af #d-c_/af #g-g_/af #c-a_/af #a-g_/af ,new ,orleans #b-aa_/af #e-c_/d #d-a_/af #b-e_/af #a-a_/h ,new ,york #b #d-e_/af #g-aa_/af #c-a_/af #a-g_/af ,omaha #b #d-e_/af #g-aa_/af #c-a_/af #a-g_/af ,philadelphia #b-a_/h #d-a_/b #g-aa_/af #b-g_/h #a-g_/af ,pittsburg #b #d-e_/af #g-aa_/af #c-a_/af #a-g_/af ,portl&1 ,me #a-ae_/af #d-c_/af #g-a_/h #c-c_/af #a-a_/b ,ri*mond #b-a_/d #d-aa_/af #h #b-g_/h #a-e_/af ,ro*e/] #a-ae_/af #d-c_/af #g-g_/af #c-a_/af #a-g_/af ,san ,diego #b-g_/af #e-c_/h #d-c_/h #b-a_/b #a-a_/h ,san ,francisco #b-a_/d #d-aa_/af #h #b-g_/h #a-e_/af ,savannah #b-i_/af #e-i_/af #d-a_/d #b-a_/b #a-a_/h ,/4 ,l\is #b-a_/d #d-aa_/af #h #b-g_/h #a-e_/af ,/4 ,paul #a-ae_/af #d-a_/af #g-a_/h #c-c_/af #a-a_/b ,seattle #a-ac_/af #c-ae_/af #f-e_/h #c-c_/h #a-a_/b ,wa%+ton1 ,d4 ,c4 #b-a_/h #d-aa_/af #h #b-g_/h #a-g_/af ---------------------------------------- -------------------------- ,! di/ance = ! l9e m>k$ ,v f ,o is j ! same z ! di/ance f ,o to ,,vii4 ,simil>ly1 ,,iv corresponds to ,,viii1 ,,iii to ,,ix1 ,,ii to ,x1 & ,i to ,,xi4 ,! numb] ,,xii is m>k$ at ,,mm z %[n4 ,if y desire to add l9es 7n %[n 9 ,fig4 #c to avoid confusion7 = h\rs e>li] ?an six 9 ! morn+1 x is m]ely necess>y to m>k (f a di/ance on ! l9e ,,ko1 bel[ ! po9t ,o1 & equal to ! di/ance f ,o to ,,vii4 ,?is w give ! po9t :]e ! #e ,a4,m4 %ad[ l9e drawn f ,n cuts ! l9e ,,ko4 ,a correspond+ l9e = #g ,p4,m4 c be drawn f ,n on ! o!r side ( ! figure4 ,aft] y h m>k$ out ! dial v c>efully1 y mu/ fa/5 ! ?ree-corn]$ %ad[-piece to x 9 su* a way t ! :ole in/rum5t w look l ,fig4 #a4 ,! edge ac 7,fig4 #b7 goes on ,,nm 7,fig4 #c74 ,! po9t a 7,fig4 #b7 mu/ come exactly on ,n 7,fig4 #c72 & z ! l9es ,,nm 7,fig4 #c7 & ,n,m 7,fig4 #c7 h be5 made j ! "r di/ance ap>t to fit ! ?ickness ( ! ?ree-corn]$ piece abc 7,fig4 #b71 ev]y?+ w g toge!r j "r4 ,! po9t c 7,fig4 #b7 w n q rea* to ,m 7,fig4 #c71 b w be on ! l9e ,,nm 7,fig4 #c7 at a di/ance ( ?ree in*es f ,m4 ,! two pieces ( wood w be fa/5$ toge!r ) ?ree screws go+ ?r\gh ! bottom-bo>d ,,abcd 7,figs4 #a & #c7 & into ! edge ac 7,fig4 #b7 ( ! ?ree-corn]$ piece4 ,! :ole in/rum5t w !n look some?+ l ,fig4 #a4 ,aft] y h got y\r sun-dial put toge!r1 y ne$ only set x 9 ! sun 9 a level place1 on a piazza or w9d[-sill1 & turn x r\nd until x tells ! "r "t by ! %ad[4 ,y c get y\r local "t f a wat* ne> en\gh = sett+ up ! dial4 ,once ! dial is set "r y c screw x d[n or m>k its position1 & x w cont9ue to give correct sol> "t e day 9 ! ye>4 ,if y wi% to adju/ ! dial v closely1 y mu/ g out "s f9e day & note ! error ( ! dial by a wat* at ab\t t5 9 ! morn+1 & at noon1 & aga9 at ab\t two 9 ! aft]noon4 ,if ! error is ! same ea* "t1 ! dial is rightly set4 ,if n1 y mu/ try1 by turn+ ! dial slightly1 to get x s plac$ t y\r ?ree errors w be ne>ly ! same4 ,:5 y h got !m z ne>ly alike z y c1 ! dial w be suffici5tly ne> "r4 ,! sol> or dial "t may1 h[ev]1 diff] some:at f ord9>y wat* "t1 b ! diff]5ce w nev] be great en\gh to matt]1 :5 we rememb] t sun-dials are only r\gh timekeep]s aft] all1 & useful pr9cipally = amusem5t4 ,,footnote3 ,a ,?is *apt] is especially int5d$ = boys & girls & o!rs :o l to make ?+s ) c>p5t]s' tools4 ,,photography ,,9 ,,a/ronomy ,new highways ( sci5ce h be5 monum5t$ n[ & aga9 by ! ma/]ful ef=ts ( g5ius1 work+ s+le-h&$2 b m (t5 x is sl[-mov+ "t t rip5s discov]y1 &1 at ! prop] mom5t1 op5s "s new pa? to m5 ^: intellectual p[] is b will+ness to le>n4 ,s ! annals ( a/ronomical photography d n rec\nt ! a*ievem5ts ( extraord9>y g5ius4 ,x w\ld h be5 /range1 inde$1 if ! discov]y ( photography _h n be5 foll[$ by its application to a/ronomy4 ,! :ole range ( *emical sci5ce conta9s no exp]im5t ( great] inh]5t int]e/ ?an ! developm5t ( a photographic plate4 ,let b ! smalle/ ray ( light fall ^u its /rangely s5sitive surface1 & "s subtle invisible *ange takes place4 ,x is !n m]ely necess>y to plunge ! plate into a prop]ly prep>$ *emical ba?1 & ! gradual process ( develop+ ! picture beg9s4 ,sl[ly1 v sl[ly1 ! colorless surface d>k5s :]ev] light has t\*$ x4 ,let u imag9e t ! exposure has be5 made ) an ord9>y l5s & cam]a1 & t x is a l&scape seem+ to gr[ b5ea? ! exp]im5t]'s eyes4 ,at fir/ only ! mo/ conspicu\s objects make _! appe>ance4 ,b gradually ! process ext5ds1 until f9ally e t9y detail is reproduc$ ) m>vell\s fidelity to ! orig9al4 ,! photographic plate1 :5 develop$ 9 ?is way1 is call$ a negative4 ,= 9 ,nature lum9\s po9ts1 or s\rces ( light1 are bright1 :ile ! develop+ negative turns d>k :]ev] light has act$4 ,?us ! negative1 :ile true to ,nature1 reproduces ev]y?+ 9 a rev]s$ way2 bright ?+s are d>k1 & %ad[s appe> light4 ,= ord9>y purposes1 !re=e1 ! negative has to be replac$ by a new photograph made by copy+ x aga9 photographically4 ,9 ?is way x is aga9 rev]s$1 giv+ u a picture correspond+ correctly to ! facts z se54 ,su* a copy f a negative is :at is ord9>ily call$ a photograph2 te*nically1 x is kn[n z a positive4 ,"o ( ! rem>kable ?+s ab\t ! s5sitive plate is its complete indiff]5ce to ! di/ance f :i* ! light comes4 ,x is ready to yield ob$i5tly to ! ray ( "s di/ant /> t may h j\rney$1 z x 71 f ! v vani%+ po9t ( space1 or to ! bright gl[ ( an electric light ^u ! photograph]'s table4 ,?is quality makes its use especially advantage\s 9 a/ronomy1 s9ce we c ga9 k ( remote />s only by a /udy ( ! light !y s5d u4 ,9 su* /udy ! photographic plate possesses a supreme advantage ov] ! human eye4 ,if ! conditions ( wea!r & atmosph]e are favorable1 an obs]v] look+ ?r\gh an ord9>y telescope w see ne>ly z mu* at ! fir/ glance z he w ev] see4 ,att5tive & cont9u$ /udy w enable him to fix details ^u 8 memory1 & to record !m by means ( draw+s & diagrams4 ,occasional mom5ts ( especially undi/urb$ atmosph]ic conditions w all[ him to glimpse fa9t objects seldom visible4 ,b on ! :ole1 telescopic a/ronom]s add little to _! h>ve/ by cont9u$ husb&ry 9 ! same field ( />s4 ,photography is diff]5t4 ,! effect ( light ^u ! s5sitive surface ( ! plate is /rictly cumulative4 ,if a giv5 /> c br+ ab\t a c]ta9 result :5 x has be5 all[$ to act ^u ! plate = "o m9ute1 !n 9 two or ?ree m9utes x w accompli% mu* m4 ,p]haps a s+le m9ute's exposure w\ld h produc$ a m>k sc>cely p]ceptible ^u ! develop$ negative4 ,9 t case1 ?ree or f\r m9utes w\ld give u a p]fectly well def9$ black image ( ! />4 ,illu/ration3 ,/>-,field 9 ,con/ellation ,monoc]os4 ,photograph$ by ,b>n>d1 ,febru>y #a1 #ahid4 ,exposure1 ?ree h\rs4 ,?us1 by l5g!n+ ! exposure we c make ! fa9t] />s impress !mselves ^u ! plate4 ,if _! light is n able to produce ! desir$ effect 9 m9utes1 we c let its action accumulate = h\rs4 ,9 ?is mann] x becomes possible & easy to photograph objects s fa9t t !y h nev] be5 se51 ev5 ) our mo/ p[]ful telescopes4 ,?is a*ievem5t ranks high among ^? :i* make a/ronomy appeal s /rongly to ! imag9ation4 ,sci5tific m5 are n giv5 to fancies2 nor %\ld !y be4 ,b ! fir/ long-exposure photograph mu/ h be5 an excit+ ?+4 ,aft] com+ f ! obs]vatory1 ! *emical developm5t 01 ( c\rse1 made 9 a d>k room1 s t no additional light might h>m ! plate until ! process 0 complete4 ,c>ry+ x out !n into ! light1 t e>ly exp]im5t] _c b h felt a ?rill ( triumph2 = 8 h& held a true picture ( dim />s to ! eye unlight$1 lift$ into view z if by magic4 ,plates h be5 ?us expos$ z long z tw5ty-five h\rs1 & ! mann] ( do+ x is v int]e/+4 ,( c\rse1 x is impossible to c>ry on ! "w cont9u\sly = s long a p]iod1 s9ce ! beg9n+ ( daylight w\ld surely ru9 ! photograph4 ,9 fact1 ! a/ronom] mu/ /op be=e ev5 ! fa9te/ /reak ( dawn beg9s to r$d5 ! ea/]n sky4 ,moreov]1 mak+ a/ronomical negatives requires excessively close att5tion1 & ?is x is impossible to give cont9u\sly dur+ m ?an a few h\rs4 ,b ! exposure ( a s+le plate c be ext5d$ ov] sev]al nights )\t difficulty4 ,x is m]ely necess>y to close ! plate-hold] ) a light-tight cov] :5 ! fir/ night's "w is f9i%$4 ,to beg9 fur!r exposure ( ! same plate on ano!r night1 we simply aim ! photographic telescope at precisely ! same po9t ( ! sky z be=e4 ,! light-tight plate-hold] be+ aga9 op5$1 ! exposure c g on z if !re _h be5 no int]ruption4 ,a/ronom]s h inv5t$ a mo/ +5i\s device = mak+ sure t ! telescope's aim c be br\ght back aga9 to ! same po9t ) great exactness4 ,?is is a v important matt]2 = ! slighte/ di/urbance ( ! plate be=e ! second or subsequ5t portions ( ! exposure w\ld ru9 ev]y?+4 ,in/ead ( a v complete s+le picture1 we %\ld h two p>tial ones mix$ up toge!r 9 inextricable confusion4 ,to prev5t ?is1 photographic telescopes are made d\ble1 n altoge!r unlike an op]a-glass4 ,"o ( ! tubes is arrang$ = photography prop]1 :ile ! o!r is fitt$ ) l5ses suitable = an ord9>y visual telescope4 ,! two tubes are made p>allel4 ,?us ! a/ronom]1 by look+ ?r\gh ! visual glass1 c wat* objects 9 ! heav5s ev5 :ile !y are be+ photograph$4 ,! visual half ( ! in/rum5t is provid$ ) a pair ( v f9e cross-wires movable at w 9 ! field ( view4 ,^! c be made to bisect "s little /> exactly1 be=e beg9n+ ! fir/ night's "w4 ,aft]w>d1 ev]y?+ ab\t ! in/rum5t hav+ be5 left un*ang$1 ! a/ronom] c always assure himself ( com+ back to precisely ! same po9t ( ! sky1 by s adju/+ ! in/rum5t t ! same little /> is aga9 bisect$4 ,x mu/ n be suppos$1 h[ev]1 t ! entire in/rum5t rema9s unmov$1 ev5 dur+ ! :ole ( a s+le night's exposure4 ,= 9 t case1 ! app>5t motion ( ! />s z !y rise or set 9 ! sky w\ld spe$ily c>ry !m out ( ! telescope's field ( view4 ,consequ5tly1 ?is motion has to be c\nt]act$ by %ift+ ! telescope s z to foll[ ! />s4 ,?is c be accompli%$ accurately & automatically by means ( clock-"w me*anism4 ,su* contrivances h already be5 appli$ 9 ! pa/ to visual telescopes1 because ev5 !n !y facilitat$ ! obs]v]'s "w4 ,!y save him ! tr\ble ( turn+ 8 in/rum5t e few m9utes1 & all[ him to give 8 undivid$ att5tion to ! actual bus9ess ( obs]vation4 ,= photographic purposes ! telescope ne$s to foll[ ! />s f> m accurately ?an 9 ! old] k9d ( obs]v+ ) ! eye4 ,nor is x possible to make a clock t w drive ! in/rum5t satisfactorily & q automatically4 ,b by means ( ! second or visual telescope1 a/ronom]s c always asc]ta9 :e!r ! clock is work+ correctly at any giv5 mom5t4 ,x requires only a glance at ! little /> bisect$ by ! cross-wires1 &1 if !re has be5 ! slighte/ imp]fection 9 ! foll[+ by clock-"w1 ! /> w no long] be cut exactly by ! wires4 ,! a/ronom] c at once correct any error by putt+ 9 op]ation a v +5i\s me*anical device sometimes call$ a m\se-control4 ,he ne$ only t\* an electric button1 & a signal is s5t into ! clock-"w4 ,in/antly !re is a %ift+ ( ! me*anism4 ,= "o ( ! regul> driv+ :eels is sub/itut$1 tempor>ily1 ano!r hav+ an extra too?4 ,?is makes ! clock run a little fa/] s long z ! electric curr5t passes4 ,9 a simil> way1 by means ( ano!r button1 ! clock c be made to run sl[] tempor>ily4 ,?us by wat*+ ! cross-wires cont9u\sly1 & manipulat+ 8 two electric buttons1 ! photographic a/ronom] c compel 8 telescope to foll[ exactly ! object "u obs]vation1 & he c make c]ta9 ( obta9+ a p]fect negative4 ,^! long-exposure plates are int5d$ especially = :at may be call$ descriptive a/ronomy4 ,) !m1 z we h se51 advantage is tak5 ( cumulative light-effects on ! s5sitive plate1 & ! telescope's light-ga!r+ & space-p5etrat+ p[]s are va/ly increas$4 ,we are enabl$ to c>ry our rese>*es f> beyond ! conf9es ( ! old visible univ]se4 ,extremely fa9t objects c be record$1 ev5 d[n to _! m9ute/ details1 ) a fidelity unkn[n to old] visual me?ods4 ,b at pres5t we int5d to consid] pr9cipally applications ( photography 9 ! a/ronomy ( measurem5t1 r ?an ! descriptive bran* ( our subject4 ,in/ead ( describ+ pictures made simply to see :at c]ta9 objects look l 9 ! sky1 we %all consid] negatives int5d$ = precise measurem5t1 ) all t ! ^w precision implies 9 cele/ial sci5ce4 ,tak+ up fir/ ! photography ( />s1 we mu/ beg9 by m5tion+ ! "w ( ,ru!rfurd at ,new ,york4 ,m ?an ?irty ye>s ago he _h s f> p]fect$ me?ods ( /ell> photography t he 0 able to secure excell5t pictures ( />s z fa9t z ! n9? magnitude4 ,9 ^? days ! mod]n process ( dry-plate photography _h n be5 inv5t$4 ,to-day1 plates expos$ 9 ! photographic telescope are made ( glass cov]$ ) a p]fectly dry film ( s5sitiz$ gelat9e4 ,b 9 ! old wet-plate process ! s5sitive film 0 fir/ wett$ ) a *emical solution2 & ?is solution c\ld n be all[$ to dry dur+ ! exposure4 ,consequ5tly1 ,ru!rfurd 0 limit$ to exposures a few m9utes 9 l5g?1 :ile n[adays1 z we h said1 _! duration c be prolong$ at w4 ,:5 we add to ?is ! fact t ! old plates 7 f> less s5sitive to light ?an ^? n[ available1 x is easy to see :at 7 ! difficulties 9 ! way ( photograph+ fa9t />s 9 ,ru!rfurd's "t4 ,nor did he possess ! mod]n +5i\s device ( a comb9$ visual & photographic in/rum5t4 ,he _h no electric controll+ app>atus4 ,9 fact1 ! y\ng] g5]ation ( a/ronom]s c =m no adequate idea ( ! pati5ce & p]sonal skill ,ru!rfurd mu/ h _h at 8 comm&4 ,= he c]ta9ly did produce negatives t are b little inf]ior to ! be/ t c be made to-day4 ,8 only limitation 0 t he c\ld n obta9 images ( />s mu* bel[ ! n9? magnitude4 ,to und]/& j :at is meant "h by ! n9? magnitude1 x is necess>y to g back 9 imag9ation to ! "t ( ,hipp>*us1 ! fa!r ( sid]eal a/ronomy4 7,see page #ci47 ,he adopt$ ! conv5i5t plan ( divid+ all ! />s visible to ! nak$ eye 7( c\rse1 he _h no telescope7 into six classes1 accord+ to _! brilliancy4 ,! fa9te/ visible />s 7 put 9 ! six? class1 & all ! o!rs 7 assign$ some:at arbitr>ily to "o or ! o!r ( ! bright] classes4 ,mod]n a/ronom]s h devis$ a m sci5tific sy/em1 :i* has be5 made to con=m v ne>ly to t ( ,hipp>*us1 j z x has come d[n to u ?r\gh ! ages4 ,we h adopt$ a c]ta9 arbitr>y degree ( lum9osity z ! /&>d fir/-magnitude2 comp>$ ) sunlight1 ?is may be repres5t$ r\ghly by a fraction ( :i* ! num]ator is #a1 & ! d5om9ator ab\t eighty ?\s& millions4 ,! /&>d second-magnitude /> is "o ^: light1 comp>$ ) a fir/-magnitude1 may be repres5t$ approximately by ! fraction 4 ,! ?ird magnitude1 9 turn1 may be comp>$ ) ! second by ! same fraction 2 & s ! classification is ext5d$ to magnitudes bel[ ^? visible to ! unaid$ eye4 ,ea* magnitude comp>es ) ! "o above x1 z ! light ( two c&les w\ld comp>e ) ! light ( five4 ,ru!rfurd did n /op ) m]e photographs4 ,he realiz$ v cle>ly ! obvi\s tru? t by mak+ a picture ( ! sky we simply *ange ! sc5e ( our op]ations4 ,^u ! photograph we c measure t :i* we might h /udi$ directly 9 ! heav5s2 b s long z !y rema9 unmeasur$1 cele/ial pictures h a pot5tial value only4 ,lock$ )9 !m may lie hidd5 "s secret ( our univ]se4 ,b x w n come =? uns\ght4 ,pati5t ef=t mu/ prec$e discov]y1 9 photography1 z else:]e 9 sci5ce4 ,!re is no royal road4 ,ru!rfurd devis$ an elaborate measur+-ma*9e 9 :i* 8 photographs c\ld be exam9$ "u ! microscope ) ! mo/ m9ute exactness4 ,) ?is ma*9e he measur$ a l>ge numb] ( 8 pictures2 & x has be5 %[n q rec5tly t ! results obta9$ f !m are comp>able 9 accuracy ) ^? com+ f ! mo/ highly accr$it$ me?ods ( direct eye-obs]vation4 ,& photographs are f> sup]ior 9 ease ( manipulation4 ,conv5i5t day-obs]v+ "u ! microscope 9 a com=table a/ronomical laboratory is sub/itut$ = all ! discom=ts ( a midnight vigil "u ! />s4 ,! "w ( measurem5t c proce$ 9 all wea!rs1 :]eas =m]ly x 0 limit$ /rictly to p]fectly cle> nights4 ,la/ly1 ! negatives =m a p]man5t record1 to :i* we c always return to correct errors or re-exam9e d\btful po9ts4 ,ru!rfurd's /ell> "w ext5d$ d[n to ab\t #ahgg1 & includ$ especially p>allax det]m9ations & ! photography ( />-clu/]s4 ,ea* ( ^! subjects is receiv+ close att5tion f lat] inve/igators1 &1 !re=e1 m]its brief m5tion "h4 ,/ell> p>allax is 9 "o s5se b ano!r "n = /ell> di/ance4 ,its measurem5t has be5 "o ( ! important problems ( a/ronomy = c5turies1 ev] s9ce m5 recogniz$ t ! ,cop]nican !ory ( our univ]se requires ! det]m9ation ( /ell> di/ances = its complete demon/ration4 ,if ! e>? is sw++ ar\nd ! sun once a ye> 9 a mighty pa? or orbit1 !re mu/ be *anges ( its position 9 space comp>able 9 size ) ! orbit itself4 ,& ! />s ought to %ift _! app>5t places on ! sky to correspond ) ^! *anges 9 ! t]re/rial obs]v]'s position4 ,! ph5om5on is analog\s to :at occurs :5 we look out ( a room1 fir/ ?r\gh "o w9d[1 & !n ?r\gh ano!r4 ,any object on ! opposite side ( ! /reet w be se5 9 a *ang$ direction1 on acc\nt ( ! obs]v]'s hav+ %ift$ 8 position f "o w9d[ to ! o!r4 ,if ! object seem$ to be due nor? :5 se5 f ! fir/ w9d[1 x w1 p]haps1 appe> a little ea/ ( nor? f ! o!r4 ,b ?is *ange ( direction w be comp>atively small1 if ! object "u obs]vation is v f> away1 9 comp>ison ) ! di/ance betwe5 ! two w9d[s4 ,?is is :at occurs ) ! />s4 ,! e>?'s orbit1 va/ z x is1 %r9ks into almo/ absolute insignificance :5 comp>$ ) ! pr(\nd di/ances by :i* we are sund]$ f ev5 ! ne>e/ fix$ />s4 ,consequ5tly1 ! %ift+ ( _! positions is also v small--s small z to be ne> ! extreme limit sep>at+ t :i* is measurable f t :i* is beyond human k54 ,photography l5ds itself mo/ readily to a /udy ( ?is matt]4 ,suppose a c]ta9 /> is suspect$ ( hav+ a p>allax4 ,9 o!r words1 we h reason to believe x ne> en\gh to admit ( a successful measurem5t ( di/ance4 ,p]haps x is a v bright />2 &1 o!r ?+s be+ equal1 x is probably fair to assume t brightness signifies ne>ness4 ,& a/ronom]s h c]ta9 o!r indications ( proximity t guide !m 9 ! selection ( prop] objects = inve/igation1 ?\gh su* evid5ce1 ( c\rse1 nev] takes ! place ( actual measurem5t4 ,! /> "u exam9ation is sure to h ne> x on ! sky a numb] ( />s s v small t we may safely take !m to be immeasurably f> away4 ,! p>allax /> is among !m1 b n ( !m4 ,we see x project$ ^u ! backgr\nd ( ! heav5s1 ?\gh x may 9 reality be q ne> u1 a/ronomically speak+4 ,if ?is is really s1 & ! />1 !re=e1 subject to ! slight p>allactic %ift+ already m5tion$1 we c detect x by not+ ! suspect$ />'s position among ! surr\nd+ small />s4 ,= ^!1 be+ immeasurably remote1 w rema9 un*ang$1 )9 ! limits ( our p[]s ( obs]vation1 & ?us s]ve z po9ts ( ref]5ce = m>k+ ! app>5t %ift+ ( ! bright] /> we are actually consid]+4 ,we h m]ely to photograph ! region at v>i\s seasons ( ! ye>4 ,c>eful exam9ation ( ! photographs "u ! microscope w !n enable u to measure ! slighte/ displacem5t ( ! p>allax />4 ,f ^! measures1 by a process ( calculation1 a/ronom]s c !n obta9 ! />'s di/ance4 ,x w n become kn[n 9 miles2 we %all only asc]ta9 h[ _m times ! di/ance betwe5 ! e>? & sun w\ld h to be laid d[n l a measur+-rod1 9 ord] to cov] ! space sep>at+ u f ! />3 & ! subsequ5t evaluation ( ?is di/ance e>? to sun 9 miles is ano!r important problem 9 ^: solution photography promises to be mo/ useful4 ,! above me?od ( measur+ /ell> di/ance is1 ( c\rse1 subject to :atev] slight unc]ta9ty arises f ! assumption t ! small />s us$ = comp>ison are !mselves beyond ! possibility ( p>allactic %ift+4 ,b a/ronomy possesses no bett] me?od4 ,moreov]1 ! numb] ( small />s us$ 9 ?is way is1 ( c\rse1 mu* l>g] 9 photography ?an x ev] c be 9 visual "w4 ,9 ! =m] process1 all surr\nd+ />s c be photograph$ at once2 9 ! latt] ea* /> mu/ be measur$ sep>ately1 & daylight soon int]v5es to impose a limit on numb]s4 ,usually only two c be us$2 s t "h photography has a mo/ important advantage4 ,x m9imizes ! *ance ( our p>allax be+ r5d]$ errone\s1 by ! />s ( comp>ison n be+ really inf9itely remote4 ,?is might happ51 p]haps1 9 ! case ( "o or two2 b ) an av]age result f a l>ge numb] we "k x to be practically impossible4 ,clu/] "w is n altoge!r unlike p>allax hunt+ 9 its prelim9>y /age ( secur+ ! photographic obs]vations4 ,! object is to obta9 an absolutely fai?ful picture ( a /> gr\p1 j z x exi/s 9 ! sky4 ,we h e reason to suppose t a v l>ge numb] ( />s cond5s$ into "o small spot ^u ! heav5s means some?+ m ?an *ance aggregation4 ,! ,pleiades gr\p 7page #aj7 conta9s ?\s&s ( massive />s1 d\btless held toge!r by ! =ce ( _! mutual gravitational attraction4 ,if ?is be true1 !re mu/ be complex orbital motion 9 ! clu/]2 &1 z "t goes on1 we %\ld actually see ! sep>ate compon5ts *ange _! relative positions1 z x 71 be=e our eyes4 ,! details ( su* motion ^u ! great scale ( cosmic space (f] "o ( ! _m problems t make a/ronomy ! gr&e/ ( human sci5ces4 ,we h said t "t mu/ pass be=e we c see ^! ?+s2 !re may be c5turies ( wait+4 ,b "o way exi/s to hurry on ! p]fection ( our k2 we mu/ increase ! precision ( obs]vations4 ,motions t w\ld ne$ ! gr[? ( c5turies to become visible to ! old] a/ronomical appliances1 might yield 9 a few decades to m delicate obs]vational processes4 ,"h photography is mo/ promis+4 ,hav+ once obta9$ a surpass+ly accurate picture ( a />-clu/]1 we c subject x easily to precise microscopic measurem5t4 ,! same op]ations repeat$ at a lat] date w enable u to comp>e ! two s]ies ( measures1 & ?us asc]ta9 ! motions t may h occurr$ 9 ! int]val4 ,! ,ru!rfurd photographs furni% a v]itable m9e ( in=mation 9 rese>*es ( ?is k9d2 = !y ant$ate all o!r cele/ial photographs ( precision by at lea/ a qu>t]-c5tury1 & br+ j s mu* ne>] ! "t :5 def9ite k %all replace in=mation bas$ on reason+ f probabilities4 ,ru!rfurd's me?ods %[$ ! advantages ( photography z appli$ to individual />-clu/]s4 ,x requir$ only ! att5tion ( "s a/ronom] dispos+ ( l>ge obs]vational facilities1 & accu/om$ to op]ations ^u a great scale1 to apply simil> me?ods ?r\gh\t ! :ole heav5s4 ,9 ! ye> #ahhb a bright comet 0 v conspicu\s 9 ! s\!rn heav5s4 ,x 0 ext5sively obs]v$ f ! s\!rn hemisph]e1 & especially at ! ,briti% ,royal ,obs]vatory at ! ,cape ( ,good ,hope4 ,gill1 director ( t in/itution1 conceiv$ ! idea t ?is comet might be bright en\gh to photograph4 ,at t "t1 comet photography _h be5 attempt$ b little1 if at all1 & x 0 by no means sure t ! exp]im5t w\ld be successful4 ,nor 0 ,gill well acqua9t$ ) ! "w ( ,ru!rfurd2 = ! be/ results ( t a/ronom] _h la9 dormant _m ye>s4 ,he 0 "o ( ^? m5 ) :om p]sonal mode/y am\nts to a fault4 ,loa? to put himself =w>d 9 any way1 & dislik+ to ru% into pr9t1 ,ru!rfurd _h giv5 b little publicity to 8 "w4 ,?is peculi>ity has1 d\btless1 delay$ 8 j reputation2 b he w lose no?+ 9 ! end f a brief po/ponem5t4 ,gill mu/1 h[ev]1 be cr$it$ ) m p5etration ?an w\ld be 8 due if ,ru!rfurd _h made x possible = o!rs to "k t he _h anticipat$ _m ( ! new] ideas4 ,h[ev] ?is may be1 ! comet 0 photograph$ ) ! help ( a local portrait photograph] nam$ ,allis4 ,:5 ,gill & ,allis fa/5$ a simple portrait cam]a belong+ to ! latt] ^u ! tube ( "o ( ! ,cape telescopes1 & po9t$ x at ! great comet1 !y little ?\ght ! exp]im5t w\ld lead to "o ( ! greate/ a/ronomical works ev] attempt$ by m54 ,yet ?is 0 de/9$ to occur4 ,! negative !y obta9$ %[$ an excell5t picture ( ! comet2 b :at 0 m important = ! future ( sid]eal a/ronomy1 x 0 also q ?ickly dott$ ) little black po9ts correspond+ to />s4 ,! extraord9>y ease ) :i* ! :ole heav5s c\ld be ?us *>t$ photographically 0 br\ght home to ,gill z nev] be=e4 ,x 0 ?is comet picture t int]e/$ him 9 ! application ( photography to />-*>t+2 & )\t 8 int]e/ ! n[ fam\s a/ro-photographic catalogue ( ! heav5s w\ld probably nev] h be5 made4 ,aft] consid]able prelim9>y correspond5ce1 a congress ( a/ronom]s 0 f9ally call$ to meet at ,p>is 9 #ahhg4 ,repres5tatives ( ! pr9cipal obs]vatories & civiliz$ gov]nm5ts 7 pres5t4 ,!y decid$ t ! end ( ! n9ete5? c5tury %\ld see ! mak+ ( a great catalogue ( all ! />s 9 ! sky1 ^u a scale ( complet5ess & precision surpass+ any?+ previ\sly attempt$4 ,x is impossible to exagg]ate ! importance ( su* a "w2 = ^u our />-catalogues dep5ds ultimately ! entire /ructure ( a/ronomical sci5ce4 ,! "w 0 f> too va/ = ! p[]s ( any obs]vatory alone4 ,!re=e1 ! :ole sky1 f pole to pole1 0 divid$ into eighte5 belts or zones ( approximately equal area2 & ea* ( ^! 0 assign$ to a s+le obs]vatory to be photograph$4 ,a s]ies ( telescopes 0 specially con/ruct$1 s t e "p ( ! "w %\ld be done ) ! same type ( in/rum5t4 ,z f> z possible1 an attempt 0 made to secure uni=mity ( me?ods1 & p>ticul>ly a uni=m scale ( precision4 ,to cov] ! entire sky ^u ! plan propos$ no less ?an #dd1ajh negatives are requir$2 & mo/ ( ^! h n[ be5 f9i%$4 ,! fur!r measurem5t ( ! pictures & ! draw+ up ( a va/ pr9t$ />-catalogue are also well "u way4 ,"o ( ! p>ticipat+ obs]vatories1 t at ,potsdam1 ,g]many1 has publi%$ ! fir/ volume ( its "p ( ! catalogue4 ,x is e/imat$ t ?is obs]vatory alone w require tw5ty qu>to volumes to conta9 m]ely ! f9al results ( its "w on ! catalogue4 ,altoge!r n less ?an two million />s w f9d a place 9 ?is1 our late/ directory ( ! heav5s4 ,su* :olesale me?ods ( attack+ problems ( obs]vational a/ronomy are p>ticul>ly *>act]i/ic ( photography4 ,! great catalogue is1 p]haps1 ! be/ illu/ration ( ?is t5d5cy2 b ( sc>cely small] int]e/1 ?\gh less important 9 reality1 is ! photographic me?od ( deal+ ) m9or planets4 ,we h already said 7page #fc7 t 9 ! space betwe5 ! orbits ( ,m>s & ,jupit] sev]al hundr$ small bodies are mov+ ar\nd ! sun 9 ord9>y planet>y orbits4 ,^! bodies are call$ a/]oids1 or m9or planets4 ,! visual me?od ( discov]+ unkn[n memb]s ( ?is gr\p 0 pa9fully t$i\s2 b photography has *ang$ matt]s completely1 & has add$ imm5sely to our k ( ! a/]oids4 ,wolf1 ( ,heidelb]g1 fir/ made use ( ! new process = m9or-planet discov]y4 ,8 me?od is suffici5tly +5i\s to des]ve brief m5tion aga94 ,a photograph ( a suitable region ( ! sky 0 made ) an exposure la/+ two or ?ree h\rs4 ,?r\gh\t all ?is "t ! in/rum5t 0 manipulat$ s z to foll[ ! motion ( ! heav5s 9 ! way we h already expla9$1 s t ea* /> w\ld appe> on ! negative z a small1 r\nd1 black dot4 ,b if a m9or planet happ5$ to be 9 ! region cov]$ by ! plate1 its photographic image w\ld be v diff]5t4 ,= ! orbital motion ( ! planet ab\t ! sun w\ld make x move a little among ! />s ev5 9 ! two or ?ree h\rs dur+ :i* ! plate 0 expos$4 ,?is motion w\ld be fai?fully reproduc$ 9 ! picture1 s t ! planet w\ld appe> z a %ort curv$ l9e r ?an a well-def9$ dot l a />4 ,?us ! pres5ce ( su* a l9e-image infallibly d5otes an a/]oid4 ,subsequ5t calculations are necess>y to asc]ta9 :e!r ! object is a planet already kn[n or a g5u9e new discov]y4 ,wolf1 & o!rs us+ 8 me?od 9 rec5t ye>s1 h made imm5se additions to our catalogue ( a/]oids4 ,inde$1 ! matt] 0 beg9n+ to lose int]e/ on acc\nt ( ! frequ5cy & sam5ess ( ^! discov]ies1 :5 ! a/ronomical _w 0 />tl$ by ! f9d+ ( ! ,planet ( #ahih4 7,page #eh47 ,on ,augu/ #bg1 #ahih1 ,witt1 ( ,b]l91 discov]$ ! small body t be>s ! numb] #dcc 9 ! li/ ( m9or planets1 & has receiv$ ! "n ,eros4 ,its important peculi>ity consi/s 9 ! exceptional position ( ! orbit4 ,:ile all ! o!r a/]oids are f>!r f ! sun ?an ,m>s1 & less di/ant ?an ,jupit]1 ,eros c pass )9 ! orbit ( ! =m]4 ,at times1 !re=e1 x w approa* our e>? m closely ?an any o!r p]man5t memb] ( ! sol> sy/em1 except+ our own moon4 ,s x is1 9 a s5se1 our ne>e/ neighbor2 & ?is fact alone makes x ! mo/ int]e/+ ( all ! m9or planets4 ,! n9ete5? c5tury 0 op5$ by ,piazzi's well-kn[n discov]y ( ! fir/ ( ^! bodies 7page #ei72 x is1 !re=e1 fitt+ t we %\ld f9d ! mo/ important "o at its close4 ,we are almo/ c]ta9 t x w be possible to make use ( ,eros to solve ) unprec$5t$ accuracy ! mo/ important problem 9 all a/ronomy4 ,?is is ! det]m9ation ( our e>?'s di/ance f ! sun4 ,:5 consid]+ /ell> p>allax1 we h se5 h[ our obs]vations enable u to measure "s ( ! />s' di/ances 9 t]ms ( ! di/ance e>? to sun z a unit4 ,x is1 inde$1 ! fundam5tal unit = all a/ronomical measures1 & its exact evaluation has always be5 consid]$ ! basal problem ( a/ronomy4 ,a/ronom]s "k x z ! problem ( ,sol> ,p>allax4 ,we %all n "h ent] into ! some:at intricate details ( ?is subject1 h[ev] int]e/+ !y may be4 ,! problem (f]s difficulties some:at analog\s to ^? confront+ a surveyor :o has to det]m9e ! di/ance ( "s inaccessible t]re/rial po9t4 ,to d ?is1 x is necess>y fir/ to measure a base-l9e1 z we call x4 ,!n ! measurem5t ( angles ) a !odolite w make x possible to d$uce ! requir$ di/ance ( ! inaccessible po9t by a process ( calculation4 ,to insure accuracy1 h[ev]1 z e surveyor kn[s1 ! base-l9e mu/ be made long en\gh2 & ?is is precisely :at is impossible 9 ! case ( ! sol> p>allax4 ,= we are necess>ily limit$ to m>k+ out our base-l9e on ! e>?2 & ! entire planet is too small to furni% "o ( really suffici5t size4 ,! be/ we c d is to use ! di/ance betwe5 two obs]vatories situat$1 z ne> z may be1 on opposite sides ( ! e>?4 ,b ev5 ?is base is w(ully small4 ,h[ev]1 ! smallness loses "s ( its h>mful effect if we op]ate ^u a planet t is comp>atively ne> u4 ,we c measure su* a planet's di/ance m accurately ?an any o!r2 & ?is be+ kn[n1 ! sol> di/ance c be comput$ by ! aid ( ma!matical consid]ations bas$ ^u ,newton's law ( gravitation & obs]vational det]m9ations ( ! planet>y orbital elem5ts4 ,photography is by no means limit$ to inve/igations 9 ! old] dep>tm5ts ( a/ronomical obs]vation4 ,its p[]ful arm has be5 /ret*$ out to grasp z well ! new] in/rum5ts ( spectroscopic /udy4 ,"h ! s5sitive plate has be5 sub/itut$ = ! human eye ) ev5 great] relative advantage4 ,! accurate microscopic measurem5t ( difficult l9es 9 /ell> spectra 0 inde$ possible by old] me?ods2 b photography has made x comp>atively easy2 &1 above all1 has r5d]$ practicable s]ies ( obs]vations ext5sive en\gh 9 numb]s to furni% /ati/ical in=mation ( real value4 ,only 9 ?is way h we be5 able to det]m9e :e!r ! />s1 9 _! v>i$ & unkn[n orbits1 are approa*+ u or mov+ f>!r away4 ,ev5 ! spe$ ( ?is approa* or recession has become measurable1 & has be5 evaluat$ 9 ! case ( _m individual />s4 7,see page #ba47 ,illu/ration3 ,sol> ,corona4 ,total ,eclipse4 ,photograph$ by ,campbell1 ,janu>y #bb1 #ahih2 ,jeur1 ,india4 ,! subject ( sol> physics has become a v]itable dep>tm5t ( a/ronomy 9 ! h&s ( photographic inve/igators4 ,+5i\s spectro-photographic me?ods h be5 devis$1 :]eby we h secur$ pictures ( ! sun f :i* we h le>n$ mu* t mu/ h rema9$ =ev] unkn[n to old] me?ods4 ,especially useful has photography prov$ itself 9 ! obs]vation ( total sol> eclipses4 ,x is only :5 ! sun's bright disk is completely obscur$ by ! int]pos$ moon t we c see ! fa9tly lum9\s /ructure ( ! sol> corona1 t great app5dage ( our sun1 ^: exact nature is /ill unexpla9$4 ,only dur+ ! few m9utes ( total eclipse 9 ea* c5tury c we look ^u x2 & ke5 is ! int]e/ ( a/ronom]s :5 ^? few m9utes occur4 ,b x is f\nd t eye obs]vations made 9 hurri$ excitem5t h comp>atively little value4 ,half a doz5 p]sons might make draw+s ( ! corona dur+ ! same eclipse1 yet !y w\ld diff] s mu* f "o ano!r z to leave ! true outl9e v mu* 9 d\bt4 ,b ) photography we c obta9 a really correct picture ^: details c be /udi$ & discuss$ subsequ5tly at leisure4 ,if we 7 ask$ to sum up 9 "o ^w :at photography has accompli%$1 we %\ld say t obs]vational a/ronomy has be5 revolutioniz$4 ,!re is to-day sc>cely an in/rum5t ( precision 9 :i* ! s5sitive plate has n be5 sub/itut$ = ! human eye2 sc>cely an inquiry possible to ! old] me?od :i* _c n[ be und]tak5 ^u a gr&] scale4 ,novel inve/igations =m]ly n ev5 possible are n[ entirely practicable by photography2 & ! end is n yet4 ,valuable z are ! a*ievem5ts already consummat$1 photography is ri*e/ 9 its promise = ! future4 ,a/ronomy has be5 call$ ! p]fect sci5ce2 x is safe to pr$ict t ! next g5]ation w wond] t ! k we h to-day %\ld ev] h receiv$ s pr\d a title4 ,,"t ,,/&>ds ,,( ,,! ,,_w ,! "q is (t5 ask$1 ,:at is ! practical use ( a/ronomy8 ,we "k1 ( c\rse1 t m5 w\ld pr(it greatly f a /udy ( t sci5ce1 ev5 if x c\ld n be turn$ to any imm$iate bread-&-butt] use2 = a/ronomy is ess5tially ! sci5ce ( big ?+s1 & x makes m5 bigg] to fix _! m9ds on problems t deal ) va/ di/ances & seem+ly endless p]iods ( "t4 ,no "o c look ^u ! quietly %9+ />s )\t be+ impress$ by ! ?\ght ( h[ !y burn$--!n z n[--be=e he himself 0 born1 & s %all cont9ue aft] he has pass$ away--aye1 ev5 aft] 8 late/ desc5dants %all h vani%$ f ! e>?4 ,( all ! sci5ces1 a/ronomy is at once ! mo/ beautiful poetically1 & yet ! "o (f]+ ! gr&e/ & mo/ difficult problems to ! intellect4 ,a /udy ( ^! problems has ev] be5 a labor ( love to ! greate/ m9ds2 _! solution has be5 c\nt$ ju/ly among man's l(tie/ a*ievem5ts4 ,& yet ( all ! difficult & ab/ruse sci5ces1 a/ronomy is1 p]haps1 ! "o t comes into ! ord9>y practical daily life ( ! p m def9itely & frequ5tly ?an any o!r4 ,!re exi/ at lea/ ?ree ?+s we owe to a/ronomy t mu/ be reg>d$ z q indisp5sable1 f a purely practical po9t ( view4 ,9 ! fir/ place1 let u consid] ! maps 9 a "w on geography4 ,h[ _m p ev] ?9k to ask h[ ^! maps are made8 ,x is true t ! ord9>y processes ( ! surveyor w\ld enable u to draw a map %[+ ! outl9es ( a "p ( ! e>?'s surface4 ,ev5 ! locations ( t[ns & riv]s might be m>k$ 9 ?is way4 ,b "o ( ! mo/ important ?+s ( all c\ld n be add$ )\t ! aid ( a/ronomical obs]vations4 ,! latitude & longitude l9es1 :i* are ess5tial to %[ ! relation ( ! map to ! re/ ( ! e>?1 we owe to a/ronomy4 ,! longitude l9es1 p>ticul>ly1 z we %all see f>!r on1 play a mo/ important "p 9 ! subject ( "t4 ,! second indisp5sable application ( a/ronomy to ord9>y bus9ess affairs relates to ! subject ( navigation4 ,h[ d %ips f9d _! way across ! ocean8 ,!re are no p]man5t m>ks on ! sea1 z !re are on ! l&1 by :i* ! navigator c guide 8 c\rse4 ,nev]!less1 seam5 "k _! pa? ov] ! trackless ocean ) a c]ta9ty z un]r+ z w\ld be possible on %ore2 & x is all done by ! help ( a/ronomy4 ,! navigator's obs]vations ( ! sun are a/ronomical obs]vations2 ! tables he uses 9 calculat+ 8 obs]vations--! tables t tell him j :]e he is & 9 :at direction he mu/ g--are a/ronomical tables4 ,inde$1 x is n too mu* to say t )\t a/ronomy !re c\ld be no safe ocean navigation4 ,b ! ?ird application ( a/ronomy is ( /ill great] importance 9 our daily life--! furni%+ ( correct "t /&>ds = all sorts ( purposes4 ,x is to ?is practical use ( a/ronomical sci5ce t we w\ld direct p>ticul> att5tion4 ,few p]sons ev] ?9k ( ! complicat$ ma*9]y t mu/ be put 9 motion 9 ord] to set a clock4 ,a man =gets "s ev5+ to w9d 8 wat* at ! accu/om$ h\r4 ,! next morn+ he f9ds x run d[n4 ,x mu/ be re-set4 ,mo/ p simply g to ! ne>e/ clock1 or ask "s fri5d = ! "t1 s z to />t ! wat* correctly4 ,m c>eful p]sons1 p]haps1 visit ! jewell]'s & take ! "t f 8 regulator4 ,b ! regulator itself ne$s to be regulat$4 ,aft] all1 x is no?+ m ?an any o!r clock1 except t great] c>e has be5 tak5 9 ! me*anical con/ruction & arrangem5t ( its v>i\s p>ts4 ,yet x is b a ma*9e built by human h&s1 &1 l all human works1 x is necess>ily imp]fect4 ,no matt] h[ well x has be5 con/ruct$1 x w n run ) p]fectly rigid accuracy4 ,e day !re w be a v>iation f ! true "t by a small am\nt1 & 9 ! c\rse ( days or weeks ! accumulation ( ^! successive small am\nts w lead to a total ( q appreciable size4 ,j z ! ord9>y citiz5 looks to ! jewell]'s regulator to correct 8 wat*1 s ! jewell] applies to ! a/ronom] = ! correction ( 8 regulator4 ,ev] s9ce ! dawn ( a/ronomy1 9 ! e>lie/ ages ( :i* we h any record1 ! pr9cipal duty ( ! a/ronom] has be5 ! furni%+ ( accurate "t to ! p4 ,we %all n "h ent] into a detail$ acc\nt1 h[ev] int]e/+ x w\ld be1 ( ! gradual developm5t by :i* ! v p]fect sy/em at pres5t 9 use has be5 rea*$2 b %all cont5t ourselves ) a description ( ! me?ods n[ employ$ 9 ne>ly all ! civiliz$ c\ntries ( ! _w4 ,9 ! fir/ place1 e obs]vatory is1 ( c\rse1 provid$ ) :at is kn[n z an a/ronomical clock4 ,?is in/rum5t1 f ! a/ronom]'s po9t ( view1 is some?+ v diff]5t f ! ord9>y popul> idea4 ,to ! av]age p]son an a/ronomical clock is a complicat$ & elaborate affair1 giv+ ! date1 day ( ! week1 phases ( ! moon1 & o!r miscellane\s in=mation4 ,b 9 reality ! a/ronom] wants none ( ^! ?+s4 ,8 "o & only requirem5t is t ! clock %all keep z ne> uni=m "t z may be possible to a ma*9e con/ruct$ by human h&s4 ,no exp5se is sp>$ 9 mak+ ! /&>d clock = an obs]vatory4 ,real arti/s 9 me*anical con/ruction--m5 :o h atta9$ a _w-wide celebrity = delicate skill 9 fa%ion+ ! p>ts ( a clock--su* are ! a/ronom]'s clock-mak]s4 ,to increase precision ( motion 9 ! tra9 ( :eels1 x is necess>y t ! me*anism be z simple z possible4 ,= ?is reason all complications ( date1 etc41 are left out4 ,we h ev5 ab&on$ ! usual conv5i5t plan ( hav+ ! h\r & m9ute h&s m\nt$ at ! same c5tre2 = ?is k9d ( m\nt+ makes necess>y a slightly m intricate =m ( :eelwork4 ,! a/ronom]'s clock usually has ! c5tres ( ! second h&1 m9ute h&1 & h\r h& 9 a /raight l9e1 & equally di/ant f ea* o!r4 ,ea* h& has its own dial2 all drawn1 ( c\rse1 ^u ! same clock-face4 ,ev5 aft] su* a clock has be5 made z accurately z possible1 x w1 nev]!less1 n give ! v be/ p]=mance unless x is tak5 c>e ( prop]ly4 ,x is necess>y to m\nt x v firmly inde$4 ,x %\ld n be fa/5$ to an ord9>y wall1 b a /rong pi] ( masonry or brick mu/ be built = x on a v solid f\ndation4 ,moreov]1 ?is pi] is be/ plac$ und]gr\nd 9 a cell>1 s t ! temp]ature ( ! clock c be kept ne>ly uni=m all ! ye> r\nd2 = we f9d t clocks d n run q ! same 9 hot wea!r z !y d 9 cold4 ,mak]s h1 inde$1 tri$ to gu>d aga9/ ?is effect ( temp]ature1 by +5i\s me*anical contrivances4 ,b ^! are nev] q p]fect 9 _! action1 & x is be/ n to te/ !m too sev]ely by expos+ ! clock to %>p *anges ( heat & cold4 ,ano!r ?+ affect+ ! go+ ( f9e clocks1 /range z x may seem1 is ! v>iation ( b>ometric pressure4 ,!re is a slight b noticeable diff]5ce 9 _! runn+ :5 ! b>omet] is high & :5 x is l[4 ,to prev5t ?is1 "s ( our be/ clocks h be5 enclos$ 9 air-tight cases1 s t outside b>ometric *anges may n be felt 9 ! lea/ by ! clock itself4 ,b ev5 aft] all ?is has be5 accompli%$1 & ! a/ronom] is 9 possession ( a clock t may be call$ a ma/]piece ( me*anical con/ruction1 he is n any bett] (f ?an 0 ! jewell] ) 8 regulator4 ,aft] all1 ev5 ! a/ronomical clock ne$s to be set1 & its error mu/ be det]m9$ f "t to "t4 ,a f9al appeal mu/ !n be _h to a/ronomical obs]vations4 ,! clock mu/ be set by ! />s & sun4 ,= ?is purpose ! a/ronom] uses an in/rum5t call$ a transit4 ,?is is simply a telescope ( mod]ate size1 possibly five or six feet long1 & firmly atta*$ to an axis at "r angles to ! tube ( ! telescope4 ,?is axis is support$ horizontally 9 su* a way t x po9ts z ne>ly z may be exactly ea/ & we/4 ,! telescope itself be+ squ>e ) ! axis1 always po9ts 9 a nor?-&-s\? direction4 ,x is possible to rotate ! telescope ab\t its axis s z to rea* all p>ts ( ! sky t are directly nor? or s\? ( ! obs]vatory4 ,9 ! field ( view ( ! telescope c]ta9 v f9e ?reads are m\nt$ s z to =m a little cross4 ,z ! telescope is rotat$ ?is cross traces out1 z x 71 a great circle on ! sky2 & ?is great circle is call$ ! a/ronomical m]idian4 ,n[ we are 9 possession ( c]ta9 />-tables1 comput$ f ! comb9$ obs]vations ( a/ronom]s 9 ! la/ #aej ye>s4 ,^! tables tell u ! exact mom5t ( "t :5 any /> is on ! m]idian4 ,to discov]1 !re=e1 :e!r our clock is "r on any giv5 night1 x is m]ely necess>y to wat* a /> ) ! telescope1 & note ! exact in/ant by ! clock :5 x rea*es ! little cross 9 ! field ( view4 ,kn[+ f ! a/ronomical tables ! "t :5 ! /> ought to h be5 on ! m]idian1 & hav+ obs]v$ ! clock "t :5 x is actually !re1 ! diff]5ce is1 ( c\rse1 ! error ( ! clock4 ,! result c be *eck$ by obs]vations ( o!r />s1 & ! slight p]sonal errors ( obs]vation c be r5d]$ h>mless by tak+ ! mean f sev]al />s4 ,by an h\r's "w on a f9e night x is possible to fix ! clock error q easily )9 ! "o-tw5tie? "p ( a second4 ,we h n space to ent] into ! int]e/+ details ( ! me?ods by :i* ! a/ronomical transit is accurately set 9 ! "r position1 & h[ any slight residual error 9 its sett+ c be elim9at$ f our results by c]ta9 processes ( computation4 ,x mu/ suffice to say t practically all "t det]m9ations 9 ! obs]vatory dep5d sub/antially ^u ! proc$ure outl9$ above4 ,! obs]vatory clock hav+ be5 once set "r by obs]vations ( ! sky1 its error c be re-det]m9$ e few days q easily4 ,?us ev5 ! small irregul>ities ( its ne>ly p]fect me*anism c be prev5t$ f accumulat+ until !y might rea* a h>mful magnitude4 ,b we obta9 9 ?is way only a correct /&>d ( "t )9 ! obs]vatory itself4 ,h[ c ?is be made available = ! g5]al public8 ,! problem is q simple ) ! aid ( ! electric telegraph4 ,we %all give a brief acc\nt ( ! me?ods n[ 9 use 9 ,new ,york ,city1 & ^! may be tak5 z ess5tially repres5tative ( ^? employ$ else:]e4 ,e day1 at noon precisely1 an electric signal is s5t out by ! ,unit$ ,/ates ,naval ,obs]vatory 9 ,wa%+ton4 ,! signal is regulat$ by ! /&>d clock ( ! obs]vatory1 ( c\rse tak+ acc\nt ( /> obs]vations made on ! next prec$+ f9e night4 ,?is signal is receiv$ 9 ! c5tral ,new ,york (fice ( ! telegraph company1 :]e x is us$ to keep correct a v f9e clock1 :i* may be call$ ! "t /&>d ( ! telegraph company4 ,?is clock1 9 turn1 has automatic electric connections1 by means ( :i* x is made to s5d out signals ov] :at are call$ "t wires t g all ov] ! city4 ,jewell]s1 & o!rs :o desire correct "t1 c arrange to h a small electric s\nd] 9 _! (fices connect$ ) ! "t wires4 ,?us ! ticks ( ! telegraph company's /&>d clock are repeat$ automatically 9 ! jewell]'s %op1 & us$ = controll+ ! exactness ( 8 regulator4 ,?is1 9 brief1 is ! me?od by :i* ! a/ronom]'s c>eful det]m9ation ( correct "t is transf]r$ & di/ribut$ to ! p at l>ge4 ,hav+ ?us outl9$ ! mann] ( obta9+ & di/ribut+ correct "t1 we %all n[ consid] ! "q ( "t diff]5ces betwe5 diff]5t places on ! e>?4 ,?is is a matt] :i* _m p]sons f9d mo/ p]plex+1 & yet x is ess5tially q simple 9 pr9ciple4 ,travell]s1 ( c\rse1 are well acqua9t$ ) ! fact t _! wat*es (t5 ne$ to be reset :5 !y arrive at _! de/9ation4 ,yet few ev] /op to ask ! cause4 ,let u consid] = a mom5t our me?od ( measur+ "t4 ,we g by ! sun4 ,if we leave out ( acc\nt "s small irregul>ities ( ! sun's motion t are ( no consequ5ce = our pres5t purpose1 we may lay d[n ?is fundam5tal pr9ciple3 ,:5 ! sun rea*es its highe/ position 9 ! sky x is twelve o'clock or noon4 ,! sun1 z ev]yone kn[s1 rises ea* morn+ 9 ! ea/1 sl[ly goes up high] & high] 9 ! sky1 & at la/ beg9s to desc5d aga9 t[>d ! we/4 ,b x is cle> t z ! sun travels f ea/ to we/1 x mu/ pass ov] ! ea/]n "o ( any two cities soon] ?an ! we/]n "o4 ,:5 x rea*es its greate/ height ov] a we/]n city x has1 !re=e1 already pass$ its greate/ height ov] an ea/]n "o4 ,9 o!r words1 :5 x is noon1 or twelve o'clock1 9 ! we/]n city1 x is already aft] noon 9 ! ea/]n city4 ,?is is ! simple & evid5t cause ( "t diff]5ces 9 diff]5t p>ts ( ! c\ntry4 ,( any two places ! ea/]n "o always has lat] "t ?an ! we/]n4 ,:5 we consid] ! matt] 9 ?is way !re is n ! slighte/ difficulty 9 und]/&+ h[ "t diff]5ces arise4 ,!y w1 ( c\rse1 be greate/ = places t are v f> ap>t 9 an ea/-&-we/ direction4 ,& ?is br+s u aga9 to ! subject ( longitude1 :i*1 z we h already said1 plays an important "p 9 all que/ions relat+ to "t2 = longitude is us$ to measure ! di/ance 9 an ea/-&-we/ direction betwe5 diff]5t p>ts ( ! e>?4 ,if we consid] ! e>? z a l>ge ball we c imag9e a s]ies ( great circles drawn on its surface & pass+ directly f ! ,nor? ,pole to ! ,s\? ,pole4 ,su* a circle c\ld be drawn ?r\gh any po9t on ! e>?4 ,if we imag9e a pair ( !m drawn ?r\gh two cities1 su* z ,new ,york & ,london1 ! longitude diff]5ce ( ^! two cities is def9$ z ! angle at ! ,nor? ,pole betwe5 ! two great circles 9 "q4 ,! size ( ?is angle c be express$ 9 degrees4 ,if we !n wi% to "k ! diff]5ce 9 "t betwe5 ,new ,york & ,london 9 h\rs1 we ne$ only divide _! longitude diff]5ce 9 degrees by ! numb] #ae4 ,9 ?is simple way we c get ! "t diff]5ce ( any two places4 ,we m]ely measure ! longitude diff]5ce on a map1 & !n divide by #ae to get ! "t diff]5ce4 ,^! "t diff]5ces c sometimes become q l>ge4 ,inde$1 = two places diff]+ #ahj degrees 9 longitude1 ! "t diff]5ce w evid5tly be no less ?an twelve h\rs4 ,mo/ civiliz$ nations h agre$ in=mally to adopt "s "o city z ! fundam5tal po9t f :i* all longitudes are to be c\nt$4 ,up to ! pres5t we h consid]$ only longitude diff]5ces2 b :5 we speak ( ! longitude ( a city we mean its longitude diff]5ce f ! place *os5 by common cons5t z ! orig9 = measur+ longitudes4 ,! t[n almo/ univ]sally us$ = ?is purpose is ,gre5wi*1 ne> ,london1 ,engl&4 ,"h is situat$ ! ,briti% ,royal ,obs]vatory1 "o ( ! olde/ & mo/ important in/itutions ( its k9d 9 ! _w4 ,! great longitude circle pass+ ?r\gh ! c5tre ( ! a/ronomical transit at ! ,gre5wi* obs]vatory is ! fundam5tal longitude circle ( ! e>?4 ,! longitude ( any o!r t[n is !n simply ! angle at ! pole betwe5 ! longitude circle ?r\gh t t[n & ! fundam5tal ,gre5wi* "o "h describ$4 ,longitudes are c\nt$ bo? ea/w>d & we/w>d f ,gre5wi*4 ,?us ,new ,york is 9 #gd degrees we/ longitude1 :ile ,b]l9 is 9 #ad degrees ea/ longitude4 ,?is has l$ to a r curi\s /ate ( affairs 9 ^? p>ts ( ! e>? ! longitudes ( :i* are ne>ly #ahj degrees ea/ or we/4 ,!re are a numb] ( isl&s 9 t "p ( ! _w1 & if we imag9e = a mom5t "o ^: longitude is j #ahj degrees1 we %all h ! foll[+ rem>kable result z to its "t diff]5ce f ,gre5wi*4 ,we h se5 t ( any two places ! ea/]n always has ! lat] "t4 ,n[1 s9ce our imag9>y isl& is exactly #ahj degrees f ,gre5wi*1 we c consid] x z be+ ei!r #ahj degrees ea/ or #ahj degrees we/4 ,b if we call x #ahj degrees ea/1 its "t w be twelve h\rs lat] ?an ,gre5wi*1 & if we call x #ahj degrees we/1 its "t w be twelve h\rs e>li] ?an ,gre5wi*4 ,evid5tly !re w be a diff]5ce ( j tw5ty-f\r h\rs1 or "o :ole day1 betwe5 ^! two possible ways ( reckon+ its "t4 ,?is circum/ance has actually l$ to consid]able confusion 9 "s ( ! isl&s ( ! ,pacific ,ocean4 ,! navigators :o discov]$ ! v>i\s isl&s naturally gave !m ! date :i* !y br\ght f ,europe4 ,& z "s ( ^! navigators sail$ ea/w>d1 ar\nd ! ,cape ( ,good ,hope1 & o!rs we/w>d1 ar\nd ,cape ,horn1 ! dates !y gave to ! sev]al isl&s diff]$ by j "o day4 ,! /ate ( affairs at ! pres5t "t has be5 adju/$ by a sort ( in=mal agreem5t4 ,an arbitr>y l9e has be5 drawn on ! map ne> ! #ahj? longitude circle1 & x has be5 decid$ t ! isl&s on ! ea/ side ( ?is l9e %all c\nt _! longitudes we/ f ,gre5wi*1 & ^? we/ ( ! l9e %all c\nt longitude ea/ f ,gre5wi*4 ,?us ,samoa is ne>ly #ahj degrees we/ ( ,gre5wi*1 :ile ! ,fiji ,isl&s are ne>ly #ahj degrees ea/4 ,yet ! isl&s are v ne> ea* o!r1 ?\gh ! arbitr>y l9e passes betwe5 !m4 ,z a result1 :5 x is ,sunday 9 ,samoa x is ,monday 9 ! ,fiji ,isl&s4 ,! arbitr>y l9e describ$ "h is sometimes call$ ! ,int]national ,date-,l9e4 ,x does n pass v ne> ! ,philipp9e ,isl&s1 :i* are situat$ 9 ab\t #abj degrees ea/ longitude1 &1 !re=e1 use a "t ab\t eight h\rs lat] ?an ,gre5wi*4 ,new ,york1 be+ ab\t #gd degrees we/ ( ,gre5wi*1 is ab\t five h\rs e>li] 9 "t4 ,consequ5tly1 z we may rem>k 9 pass+1 ,philipp9e "t is ab\t ?irte5 h\rs lat] ?an ,new ,york "t4 ,?us1 five o'clock1 ,sunday morn+1 ,may #a/1 9 ,manila1 w\ld correspond to f\r o'clock1 ,saturday aft]noon1 ,april #cj?1 9 ,new ,york4 ,!re is ano!r k9d ( "t :i* we %all expla9 briefly--! s-call$ /&>d1 or railroad "t1 :i* came into g5]al use 9 ! ,unit$ ,/ates "s few ye>s ago1 & has s9ce be5 g5]ally adopt$ ?r\gh\t ! _w4 ,x requires b a few mom5ts' consid]ation to see t ! accid5tal situation ( ! diff]5t l>ge cities 9 any c\ntry w cause _! local times to diff] by odd numb]s ( h\rs1 m9utes1 & seconds4 ,?us a great deal ( inconv5i5ce has be5 caus$ 9 ! pa/4 ,= in/ance1 a tra9 might leave ,new ,york at a c]ta9 h\r by ,new ,york "t4 ,x w\ld !n arrive 9 ,buffalo "s h\rs lat] by ,new ,york "t4 ,b x w\ld leave ,buffalo by ,buffalo "t1 :i* is q diff]5t4 ,?us !re w\ld be a sort ( jump 9 ! "t-table at ,buffalo1 & x w\ld be a jump ( an odd numb] ( m9utes4 ,x w\ld be diff]5t 9 diff]5t cities1 & v h>d to rememb]4 ,inde$1 z ea* railway usually ran its tra9s by ! "t us$ 9 ! pr9cipal city along its l9e1 x might happ5 t ?ree or f\r diff]5t railroad times w\ld be us$ 9 a s+le city :]e sev]al roads met4 ,?is has all be5 avoid$ by introduc+ ! /&>d "t sy/em4 ,accord+ to ?is ! :ole c\ntry is divid$ into a s]ies ( "t zones1 fifte5 degrees wide1 & s arrang$ t ! middle l9e ( ea* zone falls at a po9t ^: longitude f ,gre5wi* is #fj1 #ge1 #ij1 #aje1 or #abj degrees4 ,! times at ^! middle l9es are1 !re=e1 e>li] ?an ,gre5wi* "t by an ev5 numb] ( h\rs4 ,?us1 = in/ance1 ! #ge-;degree l9e is j five ev5 h\rs e>li] ?an ,gre5wi* "t4 ,all cities simply use ! "t ( ! ne>e/ "o ( ^! special l9es4 ,?is does n result 9 do+ away ) "t diff]5ces altoge!r--t w\ld1 ( c\rse1 be impossible 9 ! nature ( ?+s--b = ! complicat$ odd diff]5ces 9 h\rs & m9utes1 we h sub/itut$ ! inf9itely simpl] s]ies ( diff]5ces 9 ev5 h\rs4 ,! travell] f ,*icago to ,new ,york c reset 8 wat* by putt+ x j "o h\r lat] on 8 arrival--! m9ute h& is kept un*ang$1 & no ,new ,york timepiece ne$ be consult$ to set ! wat* "r on arriv+4 ,!re c be no d\bt t ?is /&>d-"t sy/em mu/ be consid]$ "o ( ! mo/ important contributions ( a/ronomical sci5ce to ! conv5i5ce ( man4 ,its value has receiv$ ! wide/ recognition1 & its use has n[ ext5d$ to almo/ all civiliz$ c\ntries--,france is ! only nation ( importance /ill rema9+ outside ! "t-zone sy/em4 ,9 ! foll[+ table we give ! /&>d "t ( ! v>i\s p>ts ( ! e>? z comp>$ ) ,gre5wi*1 toge!r ) ! date ( adopt+ ! new "t sy/em4 ,x w be notic$ t 9 c]ta9 cases ev5 half-h\rs h be5 employ$ to sep>ate ! "t-zones1 in/ead ( ev5 h\rs z us$ 9 ! ,unit$ ,/ates4 ,,table ,,( ,,! ,,_w',s ,,"t ,,/&>ds ---------------------------------------- --------------- ,:5 x is ,noon ,date ( ,adopt+ at ,gre5wi* ,9 ,/&>d ,"t x is ,sy/em4 ---------------------------------------- --------------- ,noon ,great ,brita94 ,belgium4 ,may1 #ahib4 ,holl&4 ,may1 #ahib4 ,spa94 ,janu>y1 #aija4 #a ,p4,m4 ,g]many4 ,april1 #ahic4 ,italy4 ,novemb]1 #ahic4 ,d5m>k4 ,janu>y1 #ahid4 ,switz]l&4 ,june1 #ahid4 ,norway4 ,janu>y1 #ahie4 ,au/ria 7railways74 #a4cj ,p4,m4 ,cape ,colony4 #ahib4 ,orange ,riv] ,colony4 #ahib4 ,transvaal4 #ahib4 #b ,p4,m4 ,natal4 ,septemb]1 #ahie4 ,turkey 7railways74 ,egypt4 ,octob]1 #aijj4 #h ,p4,m4 ,we/ ,au/ralia4 ,febru>y1 #ahie4 #i ,p4,m4 ,japan4 #ahif4 #i4cj ,p4,m4 ,s\? ,au/ralia4 ,may1 #ahii4 #aj ,p4,m4 ,victoria4 ,febru>y1 #ahie4 ,new ,s\? ,wales4 ,febru>y1 #ahie4 ,que5sl&4 ,febru>y1 #ahie4 #aa ,p4,m4 ,new ,zeal&4 ---------------------------------------- --------------- ,9 ! ,unit$ ,/ates & ,canada x is #d ,a4,m4 by ,pacific ,"t :5 x is ,noon at ,gre5wi*4 #e ,a4,m4 ,m\nta9 #f ,a4,m4 ,c5tral #g ,a4,m4 ,ea/]n #h ,a4,m4 ,colonial ,,motions ,,( ,,! ,,e>?',s ,,pole ,/ud5ts ( geology h be5 puzzl$ = _m ye>s by traces rema9+ f ! p]iod :5 a l>ge "p ( ! e>? 0 cov]$ ) a heavy cap ( ice4 ,^! %r$s ( evid5ce all seem to po9t to ! conclusion t ! c5tre ( ! ice-cov]$ region 0 q f> away f ! pres5t position ( ! nor? pole ( ! e>?4 ,if we are to reg>d ! pole z v ne> ! po9t ( greate/ cold1 x becomes a matt] ( mu* int]e/ to exam9e :e!r ! pole has always occupi$ its pres5t position1 or :e!r x has be5 subject to sl[ *anges ( place ^u ! e>?'s surface4 ,!re=e1 ! geologi/s h appeal$ to a/ronom]s to discov] :e!r !y are 9 possession ( any obs]vational evid5ce t5d+ to %[ t ! pole is 9 motion4 ,n[ we may say at once t a/ronomical rese>* has n z yet reveal$ ! evid5ce ?us expect$4 ,a/ronomy has be5 unable to come to ! rescue ( geological !ory4 ,f ab\t ! ye> #agej1 :i* saw ! beg9n+ ( precise obs]vation 9 ! mod]n s5se1 d[n to v rec5t times1 a/ronom]s 7 compell$ to d5y ! possibility ( any appreciable motion ( ! pole4 ,obs]vational processes1 x is true1 furni%$ slightly div]g5t pole positions f "t to "t4 ,yet ^! discrepancies 7 always s m9ute z to be indi/+ui%able f ^? slight p]sonal errors t are ev] insep>able f results obta9$ by ! fallible human eye4 ,b 9 ! la/ few ye>s improv$ me?ods ( obs]vation1 c\pl$ ) extreme dilig5ce 9 _! application by a/ronom]s g5]ally1 h br\ght to light a c]ta9 small motion ( ! pole :i* _h nev] be=e be5 demon/rat$ 9 a reliable way4 ,?is motion1 x is true1 is n ( ! "* dem&$ by geological !ory1 = ! geologi/s _h be5 l$ to expect a motion :i* w\ld be cont9u\s 9 ! same direction1 no matt] h[ sl[ might be its annual am\nt2 = ! va/ ext5t ( geologic "t w\ld give ev5 ! sl[e/ ( motions an opportunity to produce l>ge effects1 provid$ its results c\ld be cont9u\sly cumulative4 ,giv5 "t en\gh1 & ! pole might move any:]e on ! e>?1 no matt] h[ sl[ might be its tortoise spe$4 ,b ! small motion we h discov]$ is nei!r cumulative nor cont9u\s 9 "o direction4 ,x is :at we call a p]iodic motion1 ! pole sw++ n[ to "o side1 & n[ to ! o!r1 ( its mean or av]age position4 ,?us ?is new discov]y _c be said to unravel ! my/]i\s puzzle ( ! geologi/s4 ,yet x is n )\t ! ke5e/ int]e/1 ev5 f _! po9t ( view2 = ! pro( ( any =m ( motion 9 a pole previ\sly suppos$ to be absolutely at re/ may mean ev]y?+4 ,no man c say :at results w be reveal$ by ! fur!r obs]vations n[ be+ cont9u$ ) great dilig5ce4 ,9 ! fir/ place1 x is important to expla9 t any su* motions z we h "u consid]ation w %[ !mselves to ord9>y obs]vational processes pr9cipally 9 ! =m ( *anges ( t]re/rial latitudes4 ,let u imag9e a pair ( /raight l9es pass+ ?r\gh ! c5tre ( ! e>? & t]m9at+1 "o at ! obs]v]'s /ation on ! e>?'s surface1 & ! o!r at t po9t ( ! equator :i* is ne>e/ ! obs]v]4 ,!n1 accord+ to ! ord9>y def9ition ( latitude1 ! angle betwe5 ^! two imag9>y l9es is call$ ! latitude ( ! po9t ( obs]vation4 ,n[ we "k1 ( c\rse1 t ! equator is ev]y:]e j #ij degrees f ! pole4 ,consequ5tly1 if ! pole is subject to any motion at all1 ! equator mu/ also p>take ( ! motion4 ,?us ! angle betwe5 our two imag9>y l9es w be affect$ directly by pol> movem5t1 & ! latitude obta9$ by a/ronomical obs]vation w be subject to q simil> *anges4 ,to cle> up ! :ole "q1 s f> z ?is c be done by ! ga!r+ ( obs]vational evid5ce1 x is only necess>y to keep up a cont9ual s]ies ( latitude det]m9ations at sev]al obs]vatories4 ,^! det]m9ations %\ld %[ small v>iations simil> 9 magnitude to ! wabbl+s ( ! pole4 ,let u n[ consid] = a mom5t :at is meant by ! axis ( ! e>?4 ,x has long be5 kn[n t ! planet has 9 g5]al ! %ape ( a ball or sph]e4 ,t ?is is s c be se5 at once f ! way %ips at sea disappe> at ! horizon4 ,z !y g f>!r & f>!r f u1 we fir/ lose sight ( ! hull1 & !n sl[ly & gradually ! sp>s & sails seem to s9k d[n into ! ocean4 ,?is proves t ! e>?'s surface is curv$4 ,t x is m or less l a sph]e is evid5t f ! fact t x always ca/s a r\nd %ad[ 9 eclipses4 ,sometimes ! e>? passes betwe5 ! sun & eclips$ moon4 ,!n we see ! e>?'s black %ad[ project$ on ! moon1 :i* w\ld o!rwise be q bright4 ,?is %ad[ has be5 obs]v$ 9 a v l>ge numb] ( su* eclipses1 & x has always be5 f\nd to h a circul> edge4 ,:ile1 !re=e1 ! e>? is ne>ly a r\nd ball1 x mu/ n be suppos$ t x is exactly sph]ical 9 =m4 ,we may disreg>d ! small irregul>ities ( its surface1 = ev5 ! greate/ m\nta9s are insignificant 9 height :5 comp>$ ) ! entire diamet] ( ! e>? itself4 ,b ev5 leav+ ^! out ( acc\nt1 ! e>? is n p]fectly sph]ical4 ,we c describe x be/ z a flatt5$ sph]e4 ,x is z ?\gh "o 7 to press a r\nd rubb] ball betwe5 two smoo? bo>ds4 ,x w\ld be flatt5$ at ! top & bottom & bulg$ out 9 ! middle4 ,?is is ! %ape ( ! e>?4 ,x is flatt5$ at ! poles & bulges out ne> ! equator4 ,! %orte/ /raight l9e t c be drawn ?r\gh ! e>?'s c5tre & t]m9at$ by ! flatt5$ p>ts ( its surface may be call$ ! e>?'s axis ( figure2 & ! two po9ts :]e ?is axis meets ! surface are call$ ! poles ( figure4 ,b ! e>? has ano!r axis1 call$ ! axis ( rotation4 ,?is is ! "o ab\t :i* ! planet turns once 9 a day1 giv+ rise to ! well-kn[n ph5om5a call$ ! ris+ & sett+ ( sun1 moon1 & />s4 ,= ^! motions ( ! heav5ly bodies are really only app>5t ones1 caus$ by an actual motion ( ! obs]v] on ! e>?4 ,! obs]v] turns ) ! e>? on its axis1 & is ?us c>ri$ pa/ ! sun & />s4 ,?is daily turn+ ( ! e>?1 !n1 takes place ab\t ! axis ( rotation4 ,n[1 x s happ5s t all k9ds ( a/ronomical obs]vations = ! det]m9ation ( latitude lead to values bas$ on ! rotation axis ( ! e>?1 & n on its axis ( figure4 ,we h se5 h[ ! e>?'s equator1 f :i* we c\nt our latitudes1 is ev]y:]e #ij degrees di/ant f ! pole4 ,b ?is pole is ! pole ( rotation1 or ! po9t at :i* ! rotation axis pi]ces ! e>?'s surface4 ,x is n ! pole ( figure4 ,x is cle> t ! latitude ( any obs]vatory w rema9 con/ant only if ! pole ( figure & ! rotation pole ma9ta9 absolutely ! same positions relatively "o to ! o!r4 ,^! two poles are actually v ne> toge!r2 inde$1 x 0 suppos$ = a v long "t t !y 7 absolutely co9cid5t1 s t !re c\ld n be any v>iations ( latitude4 ,b x n[ appe>s t !y are sep>at$ slightly4 ,/range to say1 "o ( !m is revolv+ ab\t ! o!r 9 a little curve4 ,! pole ( figure is travell+ ar\nd ! pole ( rotation4 ,! di/ance betwe5 !m v>ies a little1 nev] becom+ great] ?an ab\t fifty feet1 & x takes ab\t f\rte5 mon?s to complete a revolution4 ,!re are "s slight irregul>ities 9 ! motion1 b1 9 ! ma91 x takes place 9 ! mann] "h /at$4 ,9 consequ5ce ( ?is rotation ( ! "o pole ab\t ! o!r1 ! pole ( figure is n[ on "o side ( ! rotation pole & n[ on ! opposite side1 b x nev] travels cont9u\sly 9 "o direction4 ,?us1 z we h already se51 ! sort ( cont9u\s motion requir$ to expla9 ! obs]v$ geological ph5om5a has n yet be5 f\nd by a/ronom]s4 ,obs]vations = ! /udy ( latitude v>iations h be5 made v ext5sively )9 rec5t ye>s bo? 9 ,europe & ! ,unit$ ,/ates4 ,x has be5 f\nd practically mo/ advantage\s to c>ry out simultane\s s]ies ( obs]vations at two obs]vatories situat$ 9 widely diff]5t p>ts ( ! e>?1 b hav+ v ne>ly ! same latitude4 ,x is !n possible to employ ! same />s = obs]vation 9 bo? places1 :]eas x w\ld be necess>y to use diff]5t sets ( />s if !re 7 mu* diff]5ce 9 ! latitudes4 ,!re is a special advantage 9 us+ ! same />s 9 bo? places4 ,we c !n det]m9e ! small diff]5ce 9 latitude betwe5 ! two p>ticipat+ obs]vatories 9 a mann] :i* w make x q free f any unc]ta9ty 9 our k ( ! positions on ! sky ( ! />s obs]v$2 =1 /range z x may seem1 our />-catalogues d n conta9 absolutely accurate numb]s4 ,l all o!r data dep5d+ on fallible human obs]vation1 !y are affect$ ) small errors4 ,b if we c det]m9e simply ! diff]5ce 9 latitude ( ! two obs]vatories1 we c discov] f its v>iation ! pa? 9 :i* ! pole is mov+4 ,if1 = in/ance1 ! obs]vatories are sep>at$ by "o-qu>t] ! circumf]5ce ( ! globe1 ! pole w be mov+ directly t[>d "o ( !m1 :5 x is n *ang+ its di/ance f ! o!r "o at all4 ,?is me?od 0 us$ = sev5 ye>s ) good effect at ! obs]vatories ( ,columbia ,univ]sity 9 ,new ,york1 & ! ,royal ,obs]vatory at ,naples1 ,italy4 ,= obta9+ its mo/ complete advantages x is1 ( c\rse1 bett] to e/abli% sev]al obs]v+ /ations on ab\t ! same p>allel ( latitude4 ,?is 0 done 9 #ahii by ! ,int]national ,geodetic ,association4 ,two /ations are 9 ! ,unit$ ,/ates1 "o 9 ,japan1 & "o 9 ,sicily4 ,we c1 !re=e1 hope confid5tly t our k z to ! puzzl+ problem ( pol> motion w soon receive v mat]ial advancem5t4 ,,saturn',s ,,r+s ,! dea? ( ,james ,e4 ,keel]1 ,director ( ! ,lick ,obs]vatory1 9 ,cali=nia 7p4 #cb71 recalls to m9d "o ( ! mo/ int]e/+ & significant ( lat] advances 9 a/ronomical sci5ce4 ,only sev5 ye>s h elaps$ s9ce ,keel] made ! rem>kable spectroscopic obs]vations :i* gave = ! fir/ "t an ocul> demon/ration ( ! true "* ( ^? my/]i\s lum9\s r+s surr\nd+ ! brilliant planet ,saturn4 ,8 results h n yet be5 made suffici5tly accessible to ! public at l>ge1 nor h !y be5 g5]ally valu$ at _! true wor?4 ,we consid] ?is "w ( ,keel]'s int]e/+1 because ! problem ( ! r+s has be5 a classic "o = _m g5]ations2 & we h be5 p>ticul>1 also1 to call x significant1 because x is pregnant ) ! possibilities ( new] me?ods ( spectroscopic rese>*1 appli$ 9 ! old] dep>tm5ts ( obs]vational a/ronomy4 ,! tr\bles ( a/ronom]s ) ! r+s began ) ! inv5tion ( ! telescope itself4 ,!y date back to #afaj1 :5 ,galileo fir/ turn$ 8 new in/rum5t to ! heav5s 7p4 #di74 ,x may be imag9$ easily t ! bright planet ,saturn 0 among ! v fir/ objects scrut9iz$ by him4 ,8 p[]ful in/rum5t magnifi$ only ab\t ?irty times1 & 01 d\btless1 mu* inf]ior to our pocket telescopes ( to-day4 ,b x %[$1 at all ev5ts1 t some?+ 0 wrong ) ,saturn4 ,galileo put x1 ,ultimam planet am t]gem9am obs]vavi 7,i h obs]v$ ! fur!/ planet to be triple74 ,x is easy to und]/& n[ h[ ,galileo's eyes deceiv$ him4 ,= a r\nd lum9\s ball l ,saturn1 surr\nd$ by a ?9 flat r+ se5 ne>ly edgewise1 really looks z if x _h two little atta*$ app5dages4 ,/range1 inde$1 x is to-day to read a sci5tific book s old t ! planet ,saturn c\ld be call$ ! fur!/ planet4 ,b x 0 ! out]mo/ kn[n 9 ,galileo's day1 & = ne>ly two c5turies aft]w>d4 ,n until #agha did ,william ,h]s*el discov] ,uranus 7p4 #ei72 & ,neptune 0 n disclos$ by ! m>vell\s ma!matical p]ception ( ,le ,v]ri] until #ahdf 7p4 #fa74 ,galileo's fur!r obs]vations ( ,saturn bo!r$ him m & m4 ,! planet's behavior became mu* worse z "t w5t on4 ,has ,saturn dev\r$ 8 *ildr51 accord+ to ! old leg5d8 he inquir$ soon aft]w>d2 = ! *ang$ positions ( e>? & planet 9 ! c\rse ( _! motions ar\nd ! sun 9 _! respective orbits _h become su* t ! r+ 0 se5 q edgewise1 & 01 !re=e1 p]fectly invisible to ,galileo's optic tube4 ,! puzzle rema9$ unsolv$ by ,galileo2 x 0 left = ano!r great man to f9d ! true answ]4 ,huyg5s1 9 #afef1 fir/ ann\nc$ t ! r+ is a r+4 ,! mann] 9 :i* ?is ann\ncem5t 0 made is *>act]i/ic ( ! "t2 to-day x seems almo/ ludicr\s4 ,huyg5s publi%$ a little pamphlet 9 #afef call$ ,de ,saturni ,luna ,obs]vatio ,nova or1 ,a ,new ,obs]vation ( ,saturn's ,moon4 ,he gave ! explanation ( :at _h be5 obs]v$ by himself & prec$+ a/ronom]s 9 ! =m ( a puzzle1 or logogriph4 ,"h is :at he _h to say ( ! ph5om5on 9 "q3 aaaaaaa ccccc d eeeee g h iiiiiii llll mm nnnnnnnnn oooo pp q rr s ttttt uuuuu4 ,x 0 n until #afei1 ?ree ye>s lat]1 9 a book entitl$ ,sy/ema ,saturnium1 t ,huyg5s re>rang$ ! above lett]s 9 _! prop] ord]1 giv+ ! ,lat9 s5t5ce3 ,annulo c+itur1 t5ui plano1 nusquam coha]5te1 ad eclipticam incl9ato4 ,translat$ into ,engli%1 ?is s5t5ce in=ms u t ! planet is girdl$ ) a ?91 flat r+1 n[h]e t\*+ ,saturn1 & incl9$ to ! ecliptic6 ,?is 0 a p]fectly correct & wond]fully sagaci\s explanation ( ^? complex & exasp]at+ly puzzl+ ph5om5a t _h be5 too difficult = no less a p]son ?an ,galileo himself4 ,x 0 an explanation t expla9$4 ,! reason = its prelim9>y ann\ncem5t 9 ! above mann] mu/ h be5 ! foll[+3 ,huyg5s 0 probably n q sure ( 8 gr\nd 9 #afef1 :ile ?ree ye>s aft]w>d he _h become q c]ta94 ,by ! publication ( ! logogriph ( #afef he secur$ = himself ! cr$it ( :at he _h done4 ,if any o!r a/ronom] _h publi%$ ! true explanation aft] #afef1 ,huyg5s c\ld h prov$ 8 claim to priority by re>rang+ ! lett]s ( 8 puzzle4 ,on ! o!r h&1 if fur!r rese>*es %[$ him t he 0 wrong1 he w\ld nev] h made kn[n ! true mean+ ( 8 logogriph1 & w\ld ?us h escap$ ! ignom9y ( mak+ an errone\s explanation4 ,?us1 ! me?od ( ann\ncem5t 0 comp>able 9 +5uity ) ! ,huyg5ian explanation itself4 ,we are compell$ to pass ov] briefly ! ent]ta9+ hi/ory ( subsequ5t obs]vations ( ! r+1 9 ord] to expla9 ! new "w ( ,keel] & o!rs4 ,cass9i1 ab\t #afge1 be5 able to %[ t ! r+ 0 d\ble2 t !re are really two indep5d5t r+s1 ) a di/9ct d>k space betwe5 !m4 ,x 0 a case ( :eels )9 :eels4 ,to our own em95t c\ntryman1 ,w4 ,c4 ,bond1 ( ,cambridge1 ,mass41 we owe ! fur!r discov]y 7,h>v>d ,college ,obs]vatory1 ,novemb]1 #ahej7 ( ! ?ird r+4 ,?is is also conc5tric ) ! o!r two1 & int]ior to !m1 b difficult to obs]ve1 because ( its mu* small] lum9osity4 ,x is almo/ transp>5t1 & ! brilliant light ( ! planet's c5tral ball is capable ( %9+ directly ?r\gh x4 ,= ?is reason ! inn] r+ is call$ ! gauze or crape r+4 ,if we add to ! above details ! fact t our mod]n l>ge telescopes %[ slight irregul>ities 9 ! surface ( ! r+s1 especially :5 se5 edgewise1 we h a brief /atem5t ( all t ! telescope has be5 able to reveal to u s9ce ,galileo's "t4 ,b ( f> great] int]e/ ?an ! m]e fact ( _! exi/5ce is ! important cosmic "q z to ! con/itution1 /ructure1 &1 above all1 durability ( ! r+ sy/em4 ,a/ronom]s (t5 use ! t]m /ability ) reg>d to cele/ial sy/ems l ! r+ sy/em ( ,saturn4 ,by ?is !y mean p]man5t durability4 ,a sy/em is /able if its v>i\s p>ts c cont9ue 9 _! pres5t relation%ip to "o ano!r1 )\t violat+ any ( ! kn[n laws ( a/ronomy4 ,:5ev] we /udy any collection ( cele/ial objects1 & endeavor to expla9 _! motions & peculi>ities1 we always seek "s explanation n inconsi/5t ) ! cont9u$ exi/5ce ( ! ph5om5a 9 "q4 ,= ?is !re is1 p]haps1 no suffici5t philosophical basis4 ,probably mu* ( ! great cele/ial procession is b a pass+ %[1 to be b = a mom5t 9 ! endless vi/a ( cosmic "t4 ,h[ev] ?is may be1 we are b\nd to assume z a work+ !ory t ,saturn has always _h ^! r+s1 & w always h !m2 & x is = u to f9d out h[ ?is is possible4 ,! problem has be5 attack$ ma!matically by v>i\s a/ronom]s1 includ+ ,laplace2 b no conclusive ma!matical treatm5t 0 obta9$ until #aheg1 :5 ,james ,cl]k ,maxwell prov$ 9 a ma/]ly mann] t ! r+s c\ld be nei!r solid nor liquid4 ,he %[$1 inde$1 t !y w\ld n la/ if !y 7 cont9u\s bodies l ! planets4 ,a big solid :eel w\ld inevitably be torn asund] by any slight di/urbance1 & !n precipitat$ ^u ! planet's surface4 ,!re=e1 ! r+s mu/ be compos$ ( an imm5se numb] ( small deta*$ p>ticles1 revolv+ ar\nd ,saturn 9 sep>ate orbits1 l s _m t9y satellites4 ,?is ma!matical !ory ( ! r+ sy/em be+ once e/abli%$1 a/ronom]s 7 m eag] ?an ev] to obta9 a visual confirmation ( x4 ,we _h1 inde$1 a sort ( analogy 9 ! assemblage ( s-call$ m9or planets 7p4 #fd71 :i* are kn[n to be revolv+ ar\nd our sun 9 orbits situat$ betwe5 ,m>s & ,jupit]4 ,"s hundr$s ( ^! are kn[n to exi/1 & probably !re are c\ntless o!rs too small = u to see4 ,su* a sw>m ( t9y p>ticles ( lum9\s matt] w\ld c]ta9ly give ! impression ( a cont9u\s solid body1 if se5 f a di/ance comp>able to t sep>at+ u f ,saturn4 ,b argum5ts f\nd$ on analogy are ( comp>atively little value4 ,a/ronom]s ne$ direct & conclusive telescopic evid5ce1 & ?is 0 lack+ until ,keel] made 8 rem>kable spectroscopic obs]vation 9 #ahie4 ,! spectroscope is a peculi> in/rum5t1 diff]5t 9 pr9ciple f any o!r us$ 9 a/ronomy2 we /udy di/ant objects ) x by analyz+ ! light !y s5d u1 r ?an by exam9+ & measur+ ! details ( _! visible surfaces4 ,! read] w recall t accord+ to ! mod]n undulatory !ory1 light consi/s simply ( a s]ies ( waves4 ,n[1 ! nature ( waves is v f> f be+ und]/ood 9 ! popul> m9d4 ,mo/ p1 = in/ance1 ?9k t ! waves ( ocean consi/ ( great masses ( wat] roll+ along ! surface4 ,?is notion d\btless arises f ! behavior ( waves :5 !y break ^u ! %ore1 =m+ :at we call surf4 ,:5 a wave meets ) an immovable body l a s& bea*1 ! wave is brok51 & ! wat] really does roll ^u ! bea*4 ,b ?is is an exceptional case4 ,f>!r away f ! %ore1 :]e ! waves are unimp$$1 !y consi/ simply ( p>ticles ( wat] mov+ /raight up & d[n4 ,none ( ! wat] is c>ri$ by m]e wave-action away f ! po9t ov] :i* x 0 situat$ at fir/4 ,tides or o!r causes may move ! wat]1 b n simple wave-motion alone4 ,t ?is is s c be prov$ easily4 ,if a *ip ( wood be ?r[n ov]bo>d f a %ip at sea x w be se5 to rise & fall a long "t on ! waves1 b x w n move4 ,simil>ly1 w9d-waves are (t5 q conspicu\s on a field ( gra92 b !y are caus$ by ! individual gra9 p>ticles mov+ up & d[n4 ,! gra9 c]ta9ly _c travel ov] ! gr\nd1 s9ce ea* p>ticle is fa/ to its own /alk4 ,b :ile ! p>ticles d n travel1 ! wave-di/urbance does4 ,at times x is transmitt$ to a consid]able di/ance f ! po9t :]e x 0 fir/ set 9 motion4 ,?us1 :5 a /one is dropp$ into /ill wat]1 ! di/urbance 7?\gh n ! wat]7 travels 9 ev]-wid5+ circles1 until at la/ x becomes too feeble = u to p]ceive4 ,light is j su* a travell+ wave-di/urbance4 ,beg9n+1 p]haps1 9 "s di/ant />1 x travels ?r\gh space1 & f9ally ! wave imp+es on our eyes l ! ocean-wave break+ on a s& bea*4 ,su* a light-wave affects ! eye 9 "s my/]i\s way4 ,we call x see+4 ,! spectroscope 7p4 #ba7 enables u to measure & c\nt ! waves rea*+ u ea* second f any s\rce ( light4 ,no matt] h[ f> away ! orig9 ( /ell> light may be1 ! spectroscope exam9es ! "* ( t light1 & tells u ! numb] ( waves set up e second4 ,x is ?is *>act]i/ic ( ! in/rum5t t has enabl$ u to make "s ( ! mo/ rem>kable obs]vations ( mod]n times4 ,if ! di/ant /> is approa*+ u 9 space1 m light-waves p] second w rea* u ?an we %\ld receive f ! same /> at re/4 ,?us if we f9d f ! spectroscope t !re are too _m waves1 we "k t ! /> is com+ ne>]2 & if !re are too few1 we c conclude ) equal c]ta9ty t ! /> is rec$+4 ,keel] 0 able to apply ! spectroscope 9 ?is way to ! planet ,saturn & to ! r+ sy/em4 ,! obs]vations requir$ dext]ity & obs]vational manipulative skill 9 a sup]lative degree4 ,^! ,keel] _h2 & ?is "w ( 8 w always rank z a classic obs]vation4 ,he f\nd by exam9+ ! light-waves f opposite sides ( ! planet t ! lum9\s ball rotat$2 = "o side 0 approa*+ u & ! o!r rec$+4 ,?is obs]vation 01 ( c\rse1 9 accord ) ! kn[n fact ( ,saturn's rotation on 8 axis4 ,) reg>d to ! r+s1 ,keel] %[$ 9 ! same way ! exi/5ce ( an axial rotation1 :i* appe>s n to h be5 satisfactorily prov$ be=e1 /range z x may seem4 ,b ! crucial po9t e/abli%$ by 8 spectroscope 0 t ! int]ior "p ( ! r+s rotates fa/] ?an ! ext]ior4 ,! velocity ( rotation dim9i%es gradually f ! inside to ! outside4 ,?is fact is absolutely inconsi/5t ) ! motion ( a solid r+2 b x fits 9 admirably ) ! !ory ( a r+ compris$ ( a va/ assemblage ( small sep>ate p>ticles4 ,?us1 = ! fir/ "t1 a/ronomy comes into possession ( an obs]vational det]m9ation ( ! nature ( ,saturn's r+s1 & ,galileo's puzzle is =ev] solv$4 ,,! ,,heliomet] ,a/ronomical discov]ies are always receiv$ by ! public ) ke5 int]e/4 ,e new fact read 9 ! great op5 book ( nature is writt5 eag]ly into ! books ( m54 ,= !re exi/s a /rong curiosity to asc]ta9 j h[ ! great] _w is built & gov]n$2 & x mu/ be admitt$ t a/ronom]s h be5 able to satisfy t curiosity ) no small measure ( success4 ,b x is seldom t we he> ( ! means by :i* ! late/ & mo/ ref9$ a/ronomical obs]vations are effect$4 ,popul> imag9ation pictures ! a/ronom]1 z he d\btless once 01 an ag$ g5tleman1 usually hav+ a long :ite be>d1 & sp5d+ entire nights />+ at ! sky ?r\gh a telescope4 ,b ! facts to-day are v diff]5t4 ,! work+ a/ronom] is an active man 9 ! prime ( life1 (t5 a "y man4 ,he wa/es no "t 9 />-gaz+4 ,8 obs]vations consi/ ( exact measurem5ts made 9 a precise1 sy/ematic1 & almo/ bus9ess-l mann]4 ,a night's wat* at ! telescope is seldom all[$ to exce$ ab\t ?ree h\rs1 s9ce x is f\nd t m cont9u$ ex]tions fatigue ! eye & lead to less accurate results4 ,to ?is1 ( c\rse1 !re h be5 _m notable exceptions1 = endurance ( sight1 l any =m ( physical /r5g?1 diff]s greatly 9 diff]5t individuals4 ,a/ronomical rese>* does n include pick+ out ! con/ellations1 & le>n+ ! ,arabic names ( individual />s4 ,^! ?+s are n )\t int]e/2 b !y belong to a/ronomy's anci5t hi/ory1 & are ( little value except to af=d amusem5t & in/ruction to successive g5]ations ( amateurs4 ,among ! in/rum5ts = c>efully plann$ measurem5ts ( precision ! heliomet] probably takes fir/ rank4 ,x is at once ! mo/ exquisitely accurate 9 its results1 & ! mo/ fatigu+ to ! obs]v]1 ( all ! v>i$ app>atus employ$ by ! a/ronom]4 ,! pr9ciple ^u :i* its con/ruction dep5ds is v peculi>1 & applies to all telescopes1 ev5 ord9>y ones = t]re/rial purposes4 ,if "p ( a telescope l5s be cov]$ up ) ! h&1 x w /ill be possible to see ?r\gh ! in/rum5t4 ,! glass l5s at ! end ( ! tube f>!/ f ! obs]v]'s eye helps to magnify di/ant objects & make !m seem ne>] by ga!r+ to a s+le po9t1 or focus1 a great] am\nt ( _! light ?an c\ld be br\ght toge!r by ! f> small] l5s 9 ! unaid$ eye4 ,! telescope might v prop]ly be lik5$ to an enl>g$ eye1 :i* c see m ?an we c1 simply because x is bigg]4 ,if a telescope l5s has a surface "o hundr$ times z l>ge z t ( ! l5s 9 our eye1 x w ga!r & br+ to a focus "o hundr$ times z mu* light f a di/ant object4 ,n[1 if any "p ( ?is telescope be cov]$1 ! rema9+ "p w1 nev]!less1 ga!r & focus light j z ?\gh ! :ole l5s 7 9 action2 only1 !re w be less light collect$ at ! focus )9 ! tube4 ,! small l5s at ! telescope's eye-end is simply a magnifi] to help our eye exam9e ! image ( any di/ant object =m$ at ! focus by ! l>ge l5s at ! f>!r end ( ! in/rum5t4 ,= ( ?is simple "* is ! op]ation ( any telescope3 ! l>ge glass l5s at "o end collects a di/ant planet's light1 & br+s x to a focus ne> ! o!r end ( ! tube1 :]e x =ms a t9y picture ( ! planet1 :i*1 9 turn1 is exam9$ ) ! little magnifi] at ! eye-end4 ,hav+ arriv$ at ! fundam5tal pr9ciple t "p ( a l5s w act 9 a mann] simil> to a :ole "o1 x is easy to expla9 ! con/ruction ( a heliomet]4 ,an ord9>y telescope l5s is saw$ 9 half by means ( a ?9 r\nd metal disk revolv$ rapidly by ma*9]y1 & f$ cont9ually ) em]y & wat] at its edge4 ,! cutt+ effect ( em]y is suffici5t to make su* a disk ent] glass mu* z an ord9>y saw p5etrates wood4 ,! two semi-l5ses1 z !y are call$1 are !n m\nt$ sep>ately 9 metal hold]s4 ,^! are atta*$ to "o end ( ! heliomet]1 call$ ! head1 9 su* a way t ! two semi-l5ses c slide side by side ^u metal guides4 ,?is head is !n fa/5$ to "o end ( a telescope tube m\nt$ 9 ! usual way4 ,! head end ( ! in/rum5t is turn$ t[>d ! sky 9 obs]v+1 & at ! eye-end is plac$ ! usual little magnifi] we h already describ$4 ,! obs]v] at ! eye-end has control ( c]ta9 rods by means ( :i* he c pu% ! semi-l5ses on _! slides 9 ! head at ! o!r end ( ! tube4 ,n[1 if he moves ! semi-l5ses s z to br+ !m side by side exactly1 ! :ole arrangem5t w act l an ord9>y telescope4 ,= ! semi-l5ses w !n fit toge!r j z if ! orig9al glass _h nev] be5 cut4 ,b if ! half-l5ses are sep>at$ a little on _! slides1 ea* w act by itself4 ,be+ slightly sep>at$1 ea* w cov] a diff]5t "p ( ! sky4 ,! :ole affair acts z if ! obs]v] at ! eye-end 7 look+ ?r\gh two telescopes at once4 ,= ea* semi-l5s acts indep5d5tly1 j z if x 7 a complete glass ( only half ! size4 ,n[1 suppose !re 7 a c\ple ( />s 9 ! sky1 "o 9 ! "p cov]$ by ! fir/ semi-l5s1 & "o 9 ! "p cov]$ by ! second4 ,! obs]v] w\ld1 ( c\rse1 see bo? />s at once ^u look+ into ! little magnifi] at ! eye-end ( ! heliomet]4 ,we mu/ rememb] t ^! />s w appe> 9 ! field ( view simply z two t9y po9ts ( light4 ,! a/ronom]1 z we h said1 is provid$ ) a simple sy/em ( long rods1 by means ( :i* he c manipulate ! semi-l5ses :ile ! obs]vation is be+ made4 ,if he slides !m v sl[ly "o way or ! o!r1 ! two />-po9ts 9 ! field ( view w be se5 to approa* ea* o!r4 ,9 ?is way !y c at la/ be br\ght s ne> toge!r t !y w =m b a s+le dot ( light4 ,obs]vation ) ! heliomet] consi/s 9 ?us br++ two />-images toge!r1 until at la/ !y are sup]impos$ "o ^u ! o!r1 & we see "o image only4 ,means are provid$ by :i* x is !n possible to measure ! am\nt ( sep>ation ( ! two half-l5ses4 ,evid5tly ! f>!r asund] on ! sky are ! two />s "u obs]vation1 ! great] w be ! sep>ation ( ! semi-l5ses necess>y to make a s+le image ( _! light4 ,?us1 measurem5t ( ! l5ses' sep>ation becomes a means ( det]m9+ ! sep>ation ( ! />s !mselves ^u ! sky4 ,! two slides 9 ! heliomet] head are suppli$ ) a pair ( v delicate measures or scales usually made ( silv]4 ,^! c be exam9$ f ! eye-end ( ! in/rum5t by look+ ?r\gh a long microscope provid$ = ?is special purpose4 ,?us an extremely precise value is obta9$ bo? ( ! sep>ation ( ! slid]s & ( ! di/ance on ! sky betwe5 ! />s "u exam9ation4 ,measures made 9 ?is way ) ! heliomet] are c\nt$ ! mo/ precise ( a/ronomical obs]vations4 ,hav+ ?us describ$ briefly ! k9d ( obs]vations obta9$ ) ! heliomet]1 we %all n[ t\* ^u _! fur!r utilization4 ,we %all take z an example b "o ( _! _m uses--t "o :i* a/ronom]s consid] ! mo/ important--! measurem5t ( /ell> di/ances4 7,see also p4 #id47 ,ev5 ! ne>e/ fix$ /> is almo/ inconceivably remote f u4 ,& a/ronom]s are imprison$ on ?is little e>?2 we _c bridge ! pr(\nd di/ance sep>at+ u f ! />s1 s z to use direct measurem5t ) tape-l9e or surveyor's *a94 ,we are =c$ to h rec\rse to "s indirect me?od4 ,suppose a c]ta9 /> is suspect$1 on acc\nt ( its brightness1 or = "s o!r reason1 ( be+ ne> u 9 space1 & s giv+ a favorable opportunity = a det]m9ation ( di/ance4 ,a c\ple ( v fa9t />s are select$ close by4 ,^!1 on acc\nt ( _! fa9tness1 ! a/ronom] may reg>d z q immeasurably f> away4 ,he !n det]m9es ) 8 heliomet] ! exact position on ! sky ( ! bright /> ) respect to ! pair ( fa9t ones4 ,half a ye> is !n all[$ to pass4 ,dur+ t "t ! e>? has be5 sw++ along 9 its annual pa? or orbit ar\nd ! sun4 ,half a ye> w h suffic$ to c>ry ! obs]v] on ! e>? to ! o!r side ( t pa?1 & he is !n #ahe1jjj1jjj miles away f 8 position at ! fir/ obs]vation4 ,ano!r det]m9ation is made ( ! bright />'s position z ref]r$ to ! two fa9t ones4 ,n[1 if all ^! />s 7 equally di/ant1 _! relative positions at ! second obs]vation w\ld be j ! same z at ! =m] "o4 ,b if1 z is v probable1 ! bright /> is v mu* ne>] u ?an are ! two fa9t ones1 we %all obta9 a diff]5t position f our second obs]vation4 ,= ! *ange ( #ahe1jjj1jjj miles 9 ! obs]v]'s location w1 ( c\rse1 affect ! direction 9 :i* we see ! ne> />1 :ile x w leave ! di/ant ones practically un*ang$4 ,)\t ent]+ into te*nical details1 we may say t f a l>ge numb] ( obs]vations ( ?is k9d1 we c obta9 ! di/ance ( ! bright /> by a process ( calculation4 ,! only ess5tial is to h an in/rum5t t c make ! actual obs]vations ( position accurately en\gh2 & 9 ?is respect ! heliomet] is /ill unexcell$4 ,,occultations ,sc>cely anyone c h wat*$ ! sky )\t notic+ h[ diff]5t is ! behavior ( our moon f t ( any o!r object we c see4 ,( c\rse1 x has ?is 9 common ) ! sun & />s & planets1 t x rises 9 ! ea/]n horizon1 sl[ly climbs ! dome ( ! sky1 & aga9 goes d[n & sets 9 ! we/4 ,?is motion ( ! heav5ly bodies is kn[n to be an app>5t "o m]ely1 & caus$ by ! turn+ ( our own e>? ^u its axis4 ,a man /&+ ^u ! e>?'s surface c look up & see above him "o-half ! great cele/ial vault1 gemm$ ) tw9kl+ />s1 & be>+1 p]haps1 )9 its ample curve "o or two s]5ely %9+ planets & ! lu/r\s moon4 ,b at any giv5 mom5t ! obs]v] c see no?+ ( ! o!r half ( ! heav5ly sph]e4 ,x is b5ea? 8 feet1 & conceal$ by ! solid bulk ( ! e>?4 ,! e>?1 h[ev]1 is turn+ on an axis1 c>ry+ ! obs]v] ) x4 ,& s x is cont9ually pres5t+ him to a new "p ( ! sky4 ,at any mom5t he sees b a s+le half-sph]e2 yet ! v next in/ant x is no long] ! same2 a small portion has pass$ out ( sight on "o side by go+ d[n beh9d ! turn+ e>?1 :ile a correspond+ new section has come into view on ! opposite side4 ,x is ?is com+ into view t we call ! ris+ ( a />2 & ! correspond+ disappe>ance on ! o!r side is call$ sett+4 ,?us ris+ & sett+ are1 ( c\rse1 due entirely to a turn+ ( ! e>?1 & n at all to actual motions ( ! />s2 & = ?is reason1 all objects 9 ! sky1 )\t exception1 mu/ rise & set aga94 ,b ! moon really has a motion ( its own 9 addition to ?is app>5t "o caus$ by ! e>?'s rotation4 ,some:]e 9 ! dawn ( "t e>ly wat*]s ( ! />s ?\ght out ^? fanci$ con/ellations t survive ev5 d[n to our own day4 ,!y plac$ ! mighty lion1 k+ ( bea/s1 ^u ! face ( night1 & ! great hunt]1 too1 arm$ ) club & dagg]1 to pursue him4 ,among ^! con/ellations ! moon ?reads h] de/9$ way1 night aft] night1 s rapidly t ! unaid$ eye c see t %e is mov+4 ,x ne$s b little p[] ( fancy's magic to recall f ! dim pa/ a picture ( "s ag$ a/ronom] grav+ ^u 8 tablets ! ,records ( ! ,moon4 ,to-night %e is ne> ! bright /> 9 ! eye ( ! ,bull4 ,& aga93 ,to-night %e rides full1 & ne> to ! he>t ( ! ,virg94 ,& :y does ! moon ride ?us ?r\gh ! />s ( night8 ,mod]n sci5ce has succe$$ 9 dis5tangl+ ! intricacies ( h] motion1 until to-day only "o or two ( ! v m9ute/ details ( t motion rema9 unexpla9$4 ,b x has be5 a h>d problem4 ,someone has well said t lun> !ory %\ld be lik5$ to a l(ty cliff ^u ^: side ! intellectual giants among m5 c m>k (f _! m5tal /ature1 b ^: height no "o ( !m may ev] hope to scale4 ,b = our pres5t purpose x is unnecess>y to pursue ! subject ( lun> motion into its ab/rus] details4 ,to und]/& :y ! moon moves rapidly among ! />s1 x is suffici5t to rememb] t %e is :irl+ quickly r\nd ! e>?1 s z to complete h] circuit 9 a little less ?an a mon?4 ,we see h] at all times project$ ^u ! di/ant backgr\nd ( ! sky on :i* are set ! /ell> po9ts ( light1 z ?\gh int5d$ = beacons to m>k ! c\rse pursu$ by moon & planets4 ,! />s !mselves h no su* motions z ! moon2 situat$ at a di/ance almo/ inconceivably great1 !y may1 inde$1 be travell]s ?r\gh empty space1 yet _! j\rneys %r9k into insignificance z se5 f di/ant e>?4 ,x requires ! mo/ delicate in/rum5ts ( ! a/ronom] to s magnify ! t9y displacem5ts ( ! />s on ! cele/ial vault t !y may be measur$ by human eyes4 ,let u aga9 recur to our suppos$ obs]v] wat*+ ! moon night aft] night1 s z to record ! />s closely approa*$ by h]4 ,:y %\ld he n "s "t or o!r be surpris$ by an approa* s close z to am\nt app>5tly to actual contact8 ,! moon cov]s q a l>ge surface on ! sky1 & :5 we rememb] ! ne>ly c\ntless numb]s ( ! />s1 x w\ld1 inde$1 be /range if !re 7 n "s beh9d ! moon z well z all ar\nd h]4 ,a mom5t's consid]ation %[s t ?is mu/ (t5 be ! case2 & 9 fact1 if ! moon's advanc+ edge be scrut9iz$ c>efully ?r\gh a telescope1 small />s c be se5 frequ5tly to disappe> beh9d x4 ,?is is a mo/ int]e/+ obs]vation4 ,at fir/ we see ! moon & /> ne> ea* o!r 9 ! telescope's field ( view4 ,b ! di/ance betwe5 !m less5s p]ceptibly1 ev5 quickly1 until at la/1 ) a />tl+ sudd5ness1 ! /> goes out ( sight beh9d ! moon4 ,aft] a "t1 rang+ f a few mom5ts to1 p]haps1 m ?an an h\r1 ! moon w pass1 & we c see ! /> sudd5ly reappe> f beh9d ! o!r edge4 ,^! int]e/+ obs]vations1 :ile n at all uncommon1 c be made only v r>ely by nak$-eye a/ronom]s4 ,! reason is simple4 ,! moon's light is s brilliant t x fairly ov]comes ! />s :5ev] !y are at all ne>1 except 9 ! case ( v bright ones4 ,small />s t c be foll[$ q easily up to ! moon's edge 9 a good telescope1 disappe> f a nak$-eye view :ile ! moon is /ill a long di/ance away4 ,b ! numb] ( v bright />s is comp>atively small1 s t x is q unusual to f9d anyone n a pr(essional a/ronom] :o has actually se5 "o ( ^! s-call$ occultations4 ,moreov]1 mo/ p are n in=m$ 9 advance ( ! occurr5ce ( an opportunity to make su* obs]vations1 al?\gh !y c be pr$ict$ q easily by ! aid ( a/ronomical calculations4 ,sometimes we h occultations ( planets1 & ^! are ! mo/ int]e/+ ( all4 ,:5 ! moon passes betwe5 u & "o ( ! l>g] planets1 x is wor? :ile to obs]ve ! ph5om5on ev5 )\t a telescope4 ,up to ?is po9t we h consid]$ occultations *iefly z be+ ( int]e/ to ! nak$-eye a/ronom]4 ,yet occultations h a real sci5tific value4 ,x is by _! means t we c1 p]haps1 be/ measure ! moon's size4 ,by not+ ) a telescope ! "t ( disappe>ance & reappe>ance ( kn[n />s1 a/ronom]s c br+ ! direct measurem5t ( ! moon's diamet] )9 ! range ( _! num]ical calculations4 ,sometimes ! moon passes ov] a cond5s$ clu/] ( />s l ! ,pleiades4 ,! results obta9able on ^! occasions are valuable 9 a v high degree1 & contribute l>gely to mak+ precise our k ( ! lun> diamet]4 ,!re is ano!r ?+ ( sci5tific int]e/ ab\t occultations1 ?\gh x has lo/ "s ( its importance 9 rec5t ye>s4 ,:5 su* an ev5t has be5 obs]v$1 ! agreem5t ( ! pr$ict$ "t ) t actually record$ by ! a/ronom] (f]s a mo/ se>*+ te/ ( ! correctness ( our !ory ( lun> motion4 ,we h already call$ att5tion to ! great inh]5t difficulty ( ?is !ory4 ,x is easy to see t by not+ ! exact in/ant ( disappe>ance ( a /> at a place on ! e>? ! latitude & longitude ( :i* are kn[n1 we c bo? *eck our calculations & ga!r mat]ial = improv+ our !ory4 ,! same pr9ciple c be us$ also 9 ! conv]se direction4 ,)9 ! limits ( precision impos$ by ! /ate ( our k ( lun> !ory1 we c utilize occultations to help det]m9e ! position on ! e>? ( places ^: longitude is unkn[n4 ,x is a v int]e/+ bit ( hi/ory t ! fir/ det]m9ation ( ! longitude ( ,wa%+ton 0 made by means ( occultations1 & t ?is e>ly det]m9ation l$ to ! f\nd+ ( ! ,unit$ ,/ates ,naval ,obs]vatory4 ,on ,m>* #bh1 #ahaj1 ,mr4 ,pitk91 ( ,connecticut1 report$ to ! ,h\se ( ,repres5tatives on lay+ a f\ndation = ! e/abli%m5t ( a fir/ m]idian = ! ,unit$ ,/ates1 by :i* a fur!r dep5d5ce on ,great ,brita9 or any o!r =eign nation = su* m]idian may be entirely remov$4 ,?is report 0 ! result ( a memorial pres5t$ by "o ,william ,lamb]t1 :o _h d$uc$ ! longitude ( ! ,capitol f an occultation obs]v$ ,octob] #bj1 #ahjd4 ,v>i\s proce$+s 7 _h 9 ,congress & 9 committee1 until at la/1 9 #ahba1 ,lamb]t 0 appo9t$ to make a/ronomical obs]vations by lun> occultations ( fix$ />s1 sol> eclipses1 or any approv$ me?od adapt$ to asc]ta9 ! longitude ( ! ,capitol f ,gre5wi*4 ,lamb]t's reports 7 made 9 #ahbb & #ahbc1 b t5 ye>s pass$ be=e ! e/abli%m5t ( a =mal ,naval ,obs]vatory "u ,goldsbor\gh1 ,wilkes1 & ,gilliss4 ,b to ,lamb]t belongs ! honor ( hav+ m>k$ out ! fir/ fundam5tal (ficial m]idian ( longitude 9 ! ,unit$ ,/ates4 ,,m\nt+ ,,great ,,telescopes ,!re are _m int]e/+ practical ?+s ab\t an a/ronomical obs]vatory ) :i* ! public seldom has an opportunity to become acqua9t$4 ,among ^!1 p]haps1 ! details connect$ ) sett+ up a great telescope take fir/ rank4 ,! writ] happ5$ to be pres5t at ! ,cape ( ,good ,hope ,obs]vatory :5 ! photographic equatorial telescope 0 be+ m\nt$1 & ! op]ation ( putt+ x 9 position may be tak5 z typical ( simil> processes else:]e4 7,see also p4 #hf47 ,illu/ration3 ,=ty-,in* ,telescope1 ,y]kes ,obs]vatory1 ,univ]sity ( ,*icago4 ,9 ! fir/ place1 x is necess>y to expla9 :at is meant by an equatorial telescope4 ,"o ( ! *ief difficulties 9 mak+ ord9>y obs]vations arises f ! ris+ & sett+ ( ! />s4 ,!y are all app>5tly mov+ across ! face ( ! sky1 usually climb+ up f ! ea/]n horizon1 only to g d[n aga9 & set 9 ! we/4 ,if1 !re=e1 we wi% to scrut9ize any giv5 object = a consid]able "t1 we mu/ move ! telescope cont9u\sly s z to keep pace ) ! motion ( ! heav5s4 ,= ?is purpose1 ! tube mu/ be atta*$ to axles1 s t x c be turn$ easily 9 any direction4 ,! equatorial m\nt+ is a device t p]mits ! telescope to be ?us aim$ at any "p ( ! sky1 & at ! same "t facilitates greatly ! op]ation ( keep+ x po9t$ correctly aft] a /> has once be5 br\ght into ! field ( view4 ,to und]/& ! equatorial m\nt+ x is necess>y to rememb] t ! ris+ & sett+ motions ( ! heav5ly bodies are app>5t ones only1 & due 9 reality to ! turn+ ( ! e>? on its own axis4 ,z ! e>? goes ar\nd1 x c>ries obs]v]1 telescope1 & obs]vatory pa/ ! />s fix$ ^u ! di/ant sky4 ,consequ5tly1 to keep a telescope po9t$ cont9u\sly at a giv5 />1 x is m]ely necess>y to rotate x /eadily backw>d ^u a suitable axis j fa/ en\gh to neutralize exactly ! turn+ ( our e>?4 ,by a suitable axis = ?is purpose we mean "o s m\nt$ z to be exactly p>allel to ! e>?'s own axis ( rotation4 ,a little reflection %[s h[ simply su* an arrangem5t w "w4 ,all ! heav5ly bodies may be reg>d$1 = practical purposes1 z excessively remote 9 comp>ison ) ! dim5sions ( our e>?4 ,! entire planet %r9ks into absolute insignificance :5 comp>$ ) ! di/ances ( ! ne>e/ objects br\ght "u obs]vation by a/ronom]s4 ,x foll[s t if we h our telescope atta*$ to su* a rotation-axis z we h describ$1 x w be j ! same = purposes ( obs]vation z ?\gh ! telescope's axis 7 n only p>allel to ! e>?'s axis1 b actually co9cid5t ) x4 ,! two axes may be sep>at$ by a di/ance equal to t betwe5 ! e>?'s surface & its c5tre2 b1 z we h said1 ?is di/ance is insignificant s f> z our pres5t object is conc]n$4 ,!re is ano!r way to arrive at ! same result4 ,we "k t ! />s 9 ris+ & sett+ all seem to revolve ab\t ! pole />1 :i* itself seems to rema9 immovable4 ,consequ5tly1 if we m\nt our telescope s t x c turn ab\t an axis po9t+ at ! pole1 we %all be able to neutralize ! rotation ( ! />s by simply turn+ ! telescope ab\t ! axis at ! prop] spe$ & 9 ! "r direction4 ,a/ronomical consid]ations tea* u t an axis ?us po9t+ at ! pole w be p>allel to ! e>?'s own axis4 ,?us we arrive at ! same fundam5tal pr9ciple = m\nt+ an a/ronomical telescope f :i*ev] po9t ( view we consid] ! subject4 ,e l>ge telescope is provid$ ) su* an axis ( rotation2 & = ! reason /at$ x is call$ ! pol> axis4 ,! telescope itself is !n call$ an equatorial4 ,! advantage ( ?is me?od ( m\nt+ is v evid5t4 ,s9ce we c foll[ ! />s' motions by turn+ ! telescope ab\t "o axis only1 x becomes a v simple matt] to accompli% ?is turn+ automatically by means ( clock-"w4 ,! foll[+ ( a /> be+ ?us provid$ = by ! device ( a pol> axis1 x is1 ( c\rse1 also necess>y to supply "s o!r motion s z to enable u to aim ! tube at any po9t 9 ! heav5s4 ,= x is obvi\s t if x 7 rigidly atta*$ to ! pol> axis1 we c\ld1 inde$1 foll[ any /> t happ5$ to be 9 ! field ( view1 b we c\ld n *ange ?is field ( view at w s z to obs]ve o!r />s or planets4 ,to accompli% ?is1 ! telescope is atta*$ to ! pol> axis by means ( a pivot4 ,by turn+ ! telescope ar\nd its pol> axis1 & also on ?is pivot1 we c f9d any object 9 ! heav5s2 & once f\nd1 we c leave to ! pol> axis & its automatic clock-"w ! task ( keep+ t object be=e ! obs]v]'s eye4 ,9 sett+ up ! ,cape ( ,good ,hope in/rum5t ! a/ronom]s 7 oblig$ to d a l>ge "p ( ! "w ( adju/m5t p]sonally4 ,f> away f ,european in/rum5t-mak]s1 ! p>ts ( ! m\nt+ & telescope _h to be assembl$1 or put toge!r1 by ! a/ronom]s ( ! ,cape ,obs]vatory4 ,a heavy pi] ( brick & masonry _h be5 prep>$ 9 advance4 ,^u ?is 0 plac$ a massive iron base1 int5d$ to support ! sup]/ructure ( pol> axis & telescope4 ,?is base re/$ on ?ree po9ts1 "o ( :i* c\ld be screw$ 9 & out1 s z to tilt ! :ole affair a little =w>d or backw>d4 ,by means ( ?is screw we effect$ ! f9al adju/m5t ( ! pol> axis to exact p>allelism ) t ( ! e>?4 ,o!r screws 7 provid$ ) :i* ! base c\ld be twi/$ a little horizontally ei!r to ! "r or left4 ,once set up 9 a position almo/ correct1 x 0 easy to p]fect ! adju/m5t by ! aid ( ^! screws4 ,aft]w>d ! tube & l5ses 7 put 9 place1 & ! clock prop]ly atta*$ inside ! big ca/-iron base4 ,?is clock-"w look$ m l a piece ( heavy ma*9]y ?an a delicate clock me*anism4 ,b x _h heavy "w to d1 c>ry+ ! massive telescope ) its weighty l5ses1 & ne$$ to be correspond+ly /rong4 ,x _h a driv+-weight ( ab\t #b1jjj p\nds1 & 0 s p[]ful t turn+ ! telescope affect$ x no m ?an ! h\r-h& ( an ord9>y clock affects ! me*anism )9 its case4 ,! f9al te/ ( ! :ole adju/m5t consi/$ 9 not+ :e!r />s once br\ght into ! telescopic field ( view c\ld be ma9ta9$ !re automatically by means ( ! clock4 ,?is object hav+ be5 atta9$ successfully1 ! in/rum5t /ood ready to be us$ 9 ! r\t9e bus9ess ( ! obs]vatory4 ,be=e leav+ ! subject ( telescope-m\nt+s1 we mu/ m5tion ! giant in/rum5t set up at ! ,p>is ,exposition ( #aijj4 ,! project ( hav+ a ,gr&e ,lunette _h be5 hail$ by newspap]s ?r\gh\t ! _w & by ! g5]al public 9 _! cu/om>y excitable way4 ,x 0 trem5d\sly ov]-adv]tis$2 exagg]at$ notions ( ! in/rum5t's p[]s 7 spread abroad & eag]ly cr$it$2 ! moon 0 to be dragg$ d[n1 z x 71 f its cu/om>y place 9 ! sky1 s ne> t we %\ld be able almo/ to t\* its surface4 ,z to ! planets--free lic5se 0 giv5 to ! j\rnali/ic imag9ation1 & !re 0 no effective limitation to ! magnific5ce ( a/ronomical discov]y practically )9 our grasp1 beyond ! necessity = pr9t$ space dem&$ by sundry w>s1 pe/il5ces1 & o!r mundane trifles4 ,illu/ration3 ,y]kes ,obs]vatory1 ,univ]sity ( ,*icago4 ,n[1 ! pres5t writ] is v f> f advocat+ a less5+ ( ! att5tion devot$ to a/ronomy4 ,r w\ld he magnify 8 (fice ?an dim9i% x4 ,b let j\rnali/ic a/ronomy be z good an imitation ( sob] sci5tific tru? z c be procur$ at space rates2 let editors enc\rage ! public to /udy ^? ?+s 9 ! sci5ce t are ennobl+ & cultivat+ to ! m9d2 let !re be an end to ! fr5zi$ ef=t to fabricate a highly color$ acc\nt ( alleg$ discov]ies ( ye/]day1 capable ( masqu]ad+ to-day "u heavy head-l9es z ,news4 ,! mann] 9 :i* ! big telescope came to be built is n )\t int]e/1 & %[s t ent]prise is f> f dead1 ev5 9 ! old c\ntries4 ,a /ock company 0 organiz$--we %\ld call x a corporation--"u ! "n ,socit de l',optique4 ,x w\ld appe> t %>es 7 regul>ly put on ! m>ket1 & t a prospectus1 m or less allur+1 0 widely di/ribut$4 ,we may say at once t ! inve/+ public did n respond ) obtrusive alacrity2 b at all ev5ts1 ! promot]s' ef=ts receiv$ suffici5t enc\ragem5t to enable !m to beg9 active "w4 ,f ! v fir/ a vigor\s attempt 0 made to utilize bo? ! res\rces ( g5u9e sci5ce & ! devices ( quasi-*>latanry4 ,x 0 ann\nc$ t ! public 7 to be admitt$ to look ?r\gh ! big glass 7app>5tly at s mu* an eye71 & _m1 d\btless1 expect$ t ! man 9 ! /reet w\ld be able to make p]sonal acqua9tance ) ! man 9 ! moon4 ,a telescopic image ( ! sun 0 to be project$ on a big scre51 & exhibit$ to a conc\rse ( spectators assembl$ 9 ris+ ti]s ( seats )9 a great amphi!atre4 ,& :5 cl\ds or o!r circum/ances %\ld prev5t obs]v+ ! planets or scrut9iz+ ! sun1 a p[]ful /]eopticon 0 to be us$4 ,artificial pictures ( ! wond]s ( heav5 7 to be project$ on ! scre51 & ! public w\ld nev] be disappo9t$4 ,x 0 arrang$ t skill$ talk]s %\ld be pres5t to expla9 all m>vels3 &1 9 %ort1 f9ancial pr(it 0 to be comb9$ ) ma*9]y = advanc+ sci5tific discov]y4 ,a/ronom]s ! _w ov] 7 circul>iz$1 ask$ to become %>ehold]s1 &1 9 default ( t1 to s5d lant]n-slides or photographs ( rem>kable cele/ial objects = exhibition 9 ! magic-lant]n "p ( ! %[4 ,! project ?us br\ght to ! att5tion ( sci5tific m5 ?ree ye>s ago did n h an attractive air4 ,x savor$ too mu* ( *>latanism4 ,b x soon appe>$ t effective gov]nm5t sanction _h be5 giv5 to ! ent]prise2 &1 above all1 t m5 ( reputation 7 all[+ ! use ( _! names 9 connection ) ! affair4 ,m important /ill1 we le>n$ t ! actual con/ruction _h be5 und]tak5 by ,gauti]1 ( ,p>is1 t f9ances 7 favorable1 & t real "w on p>ts ( ! in/rum5t 0 to comm5ce )\t delay4 ,gauti] is a fir/-class in/rum5t-build]2 he has e/abli%$ 8 reputation by con/ruct+ successfully sev]al telescopes ( v l>ge size1 includ+ ! equatorial c\d ( ! ,p>is ,obs]vatory1 a unique in/rum5t ( especial complexity4 ,! pres5t writ] believes t1 if suffici5t "t & money 7 available1 ! ,gr&e ,lunette w\ld /& a reasonable *ance ( success 9 ! h&s ( su* a man4 ,& by a reasonable *ance1 we mean t !re is a l>ge en\gh probability ( g5u9e sci5tific discov]y to ju/ify ! necess>y f9ancial outlay4 ,b ! project %\ld be divorc$ f its popul> features1 & e k9d ( adv]tis+ & *>latanism exclud$ ) rigor4 ,z plann$ orig9ally1 & actually con/ruct$1 ! ,gr&e ,lunette pres5ts int]e/+ peculi>ities1 di/+ui%+ x f o!r telescopes4 ,previ\s in/rum5ts h be5 built on ! pr9ciple ( univ]sal mobility4 ,x is possible to move !m 9 all directions1 & ?us br+ any desir$ /> "u obs]vation1 irrespective ( its position 9 ! sky4 ,b ?is g5]al mobility (f]s great difficulties 9 ! case ( l>ge & pond]\s telescopes4 ,delicacy ( adju/m5t is almo/ de/roy$ :5 ! object to be adju/$ weighs sev]al tons4 ,& ! excessive weight ( telescopes is n due to unavoidably heavy l5ses alone4 ,x is ess5tial t ! tube be long2 & great l5g? involves appreciable ?ickness ( mat]ial1 if /iffness & solidity are to rema9 unsacrific$4 ,l5g? 9 ! tube is necessitat$ by c]ta9 peculi> optical defects ( all l5ses1 into ! nature ( :i* we %all n ent] at pres5t4 ,! consequ5ces ( ^! defects c be r5d]$ h>mless only if ! in/rum5t is s arrang$ t ! obs]v]'s eye is f> f ! o!r end ( ! tube4 ,! l5g? ( a good telescope %\ld be at lea/ twelve times ! diamet] ( its l>ge l5s4 ,if ! relative l5g? c be /ill fur!r increas$1 s mu* ! bett]2 = !n ! optical defects c be fur!r r$uc$4 ,9 ! case ( ! ,p>is in/rum5t a radical dep>ture consi/s 9 mak+ ! tube ( unprec$5t$ l5g?1 #aig feet1 ) a l5s diamet] ( #di in*es4 ,?is great l5g?1 :ile favorable optically1 precludes ! possibility ( mak+ ! in/rum5t movable 9 ! usual s5se4 ,9 fact1 ! entire tube is atta*$ to a fix$ horizontal base1 & no attempt is made to *ange its position4 ,outside ! big l5s1 & disconnect$ altoge!r f ! telescope prop]1 is m\nt$ a smoo? mirror1 s arrang$ t x c be turn$ 9 any direction1 & ?us v>i\s p>ts ( ! sky exam9$ by reflection 9 ! telescope4 ,:ile ?is me?od unque/ionably has ! advantage ( leav+ ! optician q free z to h[ long he w make 8 tube1 x suff]s f ! comp5sat+ objection t a new optical surface is introduc$ into ! comb9ation1 viz41 ! mirror4 ,any slight unavoidable imp]fection 9 ! poli%+ ( its surface w infallibly be reproduc$ on a magnifi$ scale 9 ! image ( a di/ant /> br\ght be=e ! obs]v]'s eye4 ,b x is n yet possible to pron\nce def9itely ^u ! m]it ( ?is =m ( in/rum5t1 s9ce1 z we h said1 ! mak] has n be5 giv5 "t en\gh to try ! idea to ! complete satisfaction ( sci5tific m54 ,9 ! e>ly "p ( ,augu/1 #aijj1 :5 ! in=mant ( ! pres5t writ] left ,p>is1 aft] s]v+ z a memb] ( ! int]national jury = judg+ in/rum5ts ( precision at ! ,exposition1 ! condition ( ! ,gr&e ,lunette 0 z foll[s3 ,two sets ( l5ses _h be5 contemplat$1 "o int5d$ = cele/ial photography1 & ! o!r to be us$ = ord9>y visual obs]vation4 ,only ! photographic l5ses _h be5 complet$1 h[ev]1 & = ?is reason ! public c\ld n be p]mitt$ to look ?r\gh ! in/rum5t4 ,! photographic l5ses 7 9 place 9 ! tube1 b at t "t _! condition 0 su* t1 ?\gh "s photographs _h be5 obta9$1 x 0 n ?\ght advisable to submit !m to ! jury4 ,consequ5tly1 ! ,lunette did n receive a prize4 ,s9ce t "t v>i\s newspap]s h report$ wond]ful results f ! telescope2 b1 disreg>d+ ! fusillade f ! s5sational press1 we may sum up ! pres5t /ate ( affairs v briefly4 ,gauti] is /ill exp]im5t+2 &1 giv5 suffici5t "t & money1 he may succe$ 9 produc+ :at a/ronom]s hope =--an in/rum5t capable ( advanc+ our k1 ev5 if t advance be only a small "o4 ,,! ,,a/ronom]',s ,,pole ,! pole ( ! froz5 ,nor? is n ! only pole s\ght ) det]m9$ ef=t by m ?an "o g5]ation ( sci5tific m54 ,up 9 ! sky a/ronom]s h ano!r pole :i* !y are foll[+ up j z vigor\sly z ev] ,arctic explor] /ruggl$ t[>d ! difficult goal ( 8 t]re/rial j\rney+4 ,! cele/ial pole is1 inde$1 a fundam5tally important ?+ 9 a/ronomical sci5ce1 & ! det]m9ation ( its exact position ^u ! sky has always engag$ ! close/ att5tion ( a/ronom]s4 ,q rec5tly new me?ods ( rese>* h be5 br\ght to be>1 promis+ a degree ( success n hi!rto atta9$ 9 ! a/ronom]s' pursuit ( _! pole4 ,9 ! fir/ place1 we mu/ expla9 :at is meant by ! cele/ial pole4 ,we h already m5tion$ ! poles ( ! e>? 7p4 #acf74 ,our planet turns once daily ^u an axis pass+ ?r\gh its c5tre1 & x is ?is rotation t causes all ! s-call$ diurnal ph5om5a ( ! heav5s4 ,ris+ & sett+ ( sun1 moon1 & />s are simply results ( ?is turn+ ( ! e>?4 ,heav5ly bodies d n really rise2 x is m]ely ! man on ! e>? :o is turn$ r\nd on an axis until he is br\ght into a position f :i* he c see !m4 ,! t]re/rial poles are ^? two po9ts on ! e>?'s surface :]e x is pi]c$ by ! rotation axis ( ! planet4 ,n[ we c1 if we *oose1 imag9e ?is axis l5g!n$ out indef9itely1 fur!r & fur!r1 until at la/ x rea*es ! great r\nd vault ( ! sky4 ,"h x w aga9 pi]ce out two pol> po9ts2 & ^! are ! cele/ial poles4 ,! :ole ?+ is ?us q easy to und]/&4 ,on ! sky ! poles are m>k$ by ! prolongation ( ! e>?'s axis1 j z on ! e>? ! poles are m>k$ by ! axis itself4 ,& ?is expla9s at once :y ! />s seem nightly to revolve ab\t ! pole4 ,if ! obs]v] is be+ turn$ r\nd ! e>?'s axis1 ( c\rse x w appe> to him z if ! />s 7 rotat+ ar\nd ! same axis 9 ! opposite direction1 j z h\ses & fields seem to fly pa/ a p]son sitt+ 9 a railway tra91 unless he /ops to rememb] t x is really himself :o is 9 motion1 & n ! trees & h\ses4 ,! exi/5ce ( su* a c5tre ( daily motions among ! />s once recogniz$1 x becomes ( int]e/ to asc]ta9 :e!r ! c5tre itself always reta9s precisely ! same position 9 ! sky4 ,x 0 discov]$ z e>ly z ! "t ( ,hipp>*us 7p4 #ci7 t su* is n ! case1 & t ! cele/ial pole is subject to a sl[ motion among ! />s on ! sky4 ,if a giv5 /> 7 to-day situat$ exactly at ! pole1 x w\ld no long] be !re aft] ! lapse ( a ye>'s "t2 = ! pole w\ld h mov$ away f x4 ,?is motion ( ! pole is call$ precession4 ,x means t c]ta9 =ces are cont9ually at "w1 compell+ ! e>?'s axis to *ange its position1 s t ! prolongation ( t axis mu/ pi]ce ! sky at a po9t :i* moves z "t goes on4 ,^! =ces are produc$ by ! gravitational attractions ( ! sun1 moon1 & planets ^u ! matt] compos+ our e>?4 ,if ! e>? 7 p]fectly sph]ical 9 %ape1 ! attractions ( ! o!r heav5ly bodies w\ld n affect ! direction ( ! e>?'s rotation-axis 9 ! lea/4 ,b ! e>? is n q globul> 9 =m2 x is flatt5$ a little at ! poles & bulges out some:at at ! equator4 7,see p4 #ace47 ,?is protub]ant matt] ne> ! equator gives ! o!r bodies 9 ! sol> sy/em an opportunity to di/urb ! e>?'s rotation4 ,! g5]al effect ( all ^! attractions is to make ! cele/ial pole move ^u ! sky 9 a circle hav+ a radius ( ab\t #bc degrees2 & x requires #be1hjj ye>s to complete a circuit ( ?is precessional cycle4 ,"o ( ! mo/ /rik+ consequ5ces ( ?is motion w be ! *ange ( ! pol> />4 ,j at pres5t ! bright /> ,pol>is 9 ! con/ellation ( ! ,little ,be> is v close to ! pole4 ,b aft] ! lapse ( suffici5t ages ! fir/-magnitude /> ,vega ( ! con/ellation ,lyra w 9 its turn become ,gu>dian ( ! ,pole4 ,x mu/ n be suppos$1 h[ev]1 t ! motion ( ! pole proce$s q uni=mly1 & 9 an exact circle2 ! v>y+ positions ( ! heav5ly bodies ^: attractions cause ! ph5om5a 9 "q are su* z to produce appreciable div]g5cies f exact circul> motion4 ,sometimes ! pole deviates a little to "o side ( ! precessional circle1 & sometimes x deviates on ! o!r side4 ,! f9al result is a sort ( wavy l9e1 half on "o side & half on ! o!r ( an av]age circul> curve4 ,x takes only n9ete5 ye>s to complete "o ( ^! little waves ( pol> motion1 s t 9 ! :ole precessional cycle ( #be1hjj ye>s !re are ab\t #a1djj ind5tations4 ,?is di/urbance ( ! pol> motion is call$ by a/ronom]s nutation4 ,! fir/ /ep 9 a /udy ( pol> motion is to devise a me?od ( f9d+ j :]e ! pole is on any giv5 date4 ,if ! a/ronom] c asc]ta9 by obs]vational processes j :]e ! pole is among ! />s at any mom5t1 & c repeat 8 obs]vations ye> aft] ye> & g5]ation aft] g5]ation1 he w possess 9 "t a complete *>t ( a small portion at lea/ ( ! cele/ial pole's va/ orbit4 ,f ?is he c obta9 necess>y data = a /udy ( ! ma!matical !ory ( attractions1 & ?us1 p]haps1 arrive at an explanation ( ! fundam5tal laws gov]n+ ! univ]se 9 :i* we live4 ,! in/rum5t :i* has be5 us$ mo/ ext5sively = ! /udy ( ^! problems is ! transit 7p4 #aah7 or ! m]idian circle4 ,?is latt] consi/s ( a telescope firmly atta*$ to a metallic axis ab\t :i* x c turn4 ,! axis itself re/s on massive /one supports1 & is s plac$ t x po9ts z ne>ly z possible 9 an ea/-&-we/ direction4 ,consequ5tly1 :5 ! telescope is turn$ ab\t its axis1 x w trace out on ! sky a great circle 7! m]idian7 :i* passes ?r\gh ! nor? & s\? po9ts ( ! horizon & ! po9t directly ov]head4 ,! in/rum5t has also a metallic circle v firmly fa/5$ to ! telescope & its axis4 ,let into ! surface ( ?is circle is a silv] disk ^u :i* are engrav$ a s]ies ( l9es or graduations by means ( :i* x is possible to measure angles4 ,obs]v]s ) ! m]idian circle beg9 by not+ ! exact in/ant :5 any giv5 /> passes ! c5tre ( ! field ( view ( ! telescope4 ,?is c5tre is m>k$ ) a cross made by fa/5+ into ! focus "s pieces ( ord9>y spid]'s web1 :i* give a well-m>k$1 delicate set ( l9es1 ev5 "u ! magnify+ p[] ( ! telescope's eye-piece4 ,9 addition to ?us not+ ! "t :5 ! /> crosses ! field ( ! telescope1 ! a/ronom] c measure by means ( ! circle1 h[ high up x 0 9 ! sky at ! in/ant :5 x 0 ?us obs]v$4 ,if ! telescope ( ! m]idian circle be turn$ t[>d ! nor?1 & we obs]ve />s close to ! pole1 x is possible to make two diff]5t obs]vations ( ! same />4 ,= ! close pol> />s revolve 9 su* small circles ar\nd ! pole ( ! heav5s t we c obs]ve !m :5 !y are on ! m]idian ei!r above ! pole or bel[ x4 ,d\ble obs]vations ( ?is class enable u to obta9 ! elevation ( ! pole above ! horizon1 & to fix its position ) respect to ! />s4 ,n[1 !re is "o v s]i\s objection to ?is me?od4 ,9 ord] to secure ! two necess>y obs]vations ( ! same />1 x is ess5tial to be /ation$ at ! in/rum5t at two mom5ts ( "t sep>at$ by exactly twelve h\rs2 & if "o ( ! obs]vations occurs 9 ! night1 ! o!r correspond+ obs]vation w occur 9 daylight4 ,x is a fact n g5]ally kn[n t ! bright] />s c be se5 ) a telescope1 ev5 :5 ! sun is q high above ! horizon4 ,un=tunately1 h[ev]1 !re is only "o /> close to ! pole :i* is bright en\gh to be ?us obs]v$ 9 daylight--! pol> /> already m5tion$ "u ! "n ,pol>is4 ,! fact t we are ?us limit$ to obs]vations ( a s+le /> has made x difficult ev5 = g5]ations ( a/ronom]s to accumulate ) ! m]idian circle a v l>ge quantity ( obs]vational mat]ial suitable = ! solution ( our problem4 ,! new me?od ( obs]vation to :i* we h ref]r$ above consi/s 9 an application ( photography to ! pol> problem4 ,if we aim at ! pole a p[]ful photographic telescope1 & expose a photographic plate ?r\gh\t ! entire night1 we %all f9d t all />s com+ )9 ! range ( ! plate w m>k out little circles or trails ^u ! develop$ negative4 ,x is evid5t t z ! />s revolve ab\t ! pole on ! sky1 trac+ out _! daily circul> orbits1 ^! same little circles mu/ be reproduc$ fai?fully ^u ! photographic plate4 ,! only condition is t ! />s %all be bright en\gh to make _! light affect ! s5sitive gelat9e surface4 ,b ev5 if obs]vations ( ?is k9d are cont9u$ ?r\gh\t all ! h\rs ( d>kness1 we d n obta9 complete circles1 b only ^? portions ( circles trac$ out on ! sky betwe5 sunset & sunrise4 ,if ! night is twelve h\rs 9 l5g?1 we get half-circles on ! plate2 if x is eighte5 h\rs long1 we get circles t lack only "o-qu>t] ( be+ complete4 ,9 o!r words1 we get a s]ies ( circul> arcs1 "o correspond+ to ea* close pol> />4 ,!re are no few] ?an sixte5 />s ne> en\gh to ! pole to come )9 ! range ( a photographic plate1 & bright en\gh to cause measurable impressions ^u ! s5sitive surface4 ,! fact t ! circul> arcs are n complete circles does n 9 ! lea/ prev5t our us+ !m = asc]ta9+ ! position ( _! common c5tre2 & t c5tre is ! pole4 ,moreov]1 z ! arcs are di/ribut$ at all sorts ( di/ances f ! pole & 9 all directions1 correspond+ to ! accid5tal positions ( ! />s on ! sky1 we h a /ate ( affairs extremely favorable to ! accurate det]m9ation ( ! pole's place among ! />s by means ( microscopic measurem5ts ( ! plate4 ,x w be p]ceiv$ t ?is me?od is extremely simple1 &1 !re=e1 likely to be successful2 ?\gh its simplicity is slightly impair$ by ! ph5om5on kn[n to a/ronom]s z atmosph]ic refraction4 ,! rays ( light com+ d[n to our telescopes f a di/ant /> mu/ pass ?r\gh ! e>?'s atmosph]e be=e !y rea* u2 & 9 pass+ ?us f ! no?+ness ( out] space into ! d5s] mat]ial ( ! air1 !y are b5t out ( _! /raight c\rse4 ,! ph5om5on is analog\s to :at we see :5 we pu% a /ick d[n ?r\gh ! surface ( /ill wat]2 we notice t ! /ick appe>s to be b5t at ! po9t :]e x pi]ces ! surface ( ! wat]2 & 9 j ! same way ! rays ( light are b5t :5 !y pi]ce into ! air4 ,=tunately1 ! ma!matical !ory ( ?is atmosph]ic b5d+ ( light is well und]/ood1 s t x is possible to remove ! effects ( refraction f our results by a process ( calculation4 ,9 o!r words1 we c trans=m our photographic measures into :at !y w\ld h be5 if no su* ?+ z atmosph]ic refraction exi/$4 ,?is hav+ be5 done1 all ! arcs on ! plate %\ld be exactly circul>1 & _! common c5tre %\ld be ! position ( ! pole among ! />s on ! night :5 ! photograph 0 made4 ,x is possible to facilitate ! removal ( refraction effects v mu* by plac+ our photographic telescope at "s po9t on ! e>? situat$ 9 a v high latitude4 ,! elevation ( ! pole above ! horizon is greate/ 9 high latitudes4 ,inde$1 if ,arctic voyag]s c\ld ev] rea* ! pole ( ! e>? !y w\ld see ! pole ( ! heav5s directly ov]head4 ,n[1 ! high] up ! pole is 9 ! sky1 ! less w be ! effects ( atmosph]ic refraction2 = ! rays ( light w !n /rike ! atmosph]e 9 a direction ne>ly p]p5dicul> to its surface1 :i* is favorable to dim9i%+ ! am\nt ( b5d+4 ,!re is also ano!r v important advantage 9 plac+ ! telescope 9 a high latitude2 9 ! middle ( w9t] ! nights are v long !re2 if we c\ld get )9 ! ,arctic4 ,circle itself1 !re w\ld be nights :5 ! h\rs ( d>kness w\ld numb] tw5ty-f\r1 & we c\ld sub/itute complete circles = our brok5 arcs4 ,?is w\ld1 inde$1 be mo/ favorable f ! a/ronomical po9t ( view2 b ! ess5tial condition ( conv5i5ce = ! obs]v] r5d]s an exp$ition to ! froz5 ,arctic regions unadvisable4 ,b x is at lea/ possible to place ! telescope z f> nor? z is consi/5t ) reta9+ x )9 ! sph]e ( civiliz$ influ5ces4 ,we c put x 9 t "o ( exi/+ obs]vatories on ! e>? :i* has ! highe/ latitude2 & ?is is ! obs]vatory ( ,hels+=s1 9 ,f9l&1 :i* belongs to a great univ]sity1 is mann$ by compet5t a/ronom]s1 & has a latitude great] ?an #fj degrees4 ,dr4 ,&]s ,donn]1 ,director ( ! ,hels+=s ,obs]vatory1 has at its disposal a f9e photographic telescope1 & ) ?is "s prelim9>y exp]im5tal trail photographs 7 made 9 #ahie4 ,^! photographs 7 s5t to ,columbia ,univ]sity1 ,new ,york1 & 7 !re measur$ "u ! writ]'s direction4 ,calculations bas$ on ^! measures indicate t ! me?od is promis+ 9 a v high degree2 & x 01 !re=e1 decid$ to con/ruct a special photographic telescope bett] adapt$ to ! p>ticul> ne$s ( ! problem 9 h&4 ,! desirability ( a new telescope arises f ! fact t we wi% ! in/rum5t to rema9 absolutely unmov$ dur+ all ! successive h\rs ( ! photographic exposure4 ,x is cle> t if ! telescope moves :ile ! />s are trac+ out _! little trails on ! plate1 ! circul>ity ( ! curves w be di/urb$4 ,n[1 ord9>y a/ronomical telescopes are always m\nt$ ^u v /able f\ndations1 well adapt$ to mak+ ! telescope /& /ill2 b ! pol> telescope :i* we wi% to use 9 a rese>* fundam5tal to ! entire sci5ce ( a/ronomy ought to possess immobility & /ability ( an ord] high] ?an t requir$ = ord9>y a/ronomical purposes4 ,x is a rem>kable peculi>ity ( ! in/rum5t ne$$ = ! new trail photographs t x is nev] mov$ at all4 ,once po9t$ at ! pole1 x is ready = all ! obs]vations ( successive g5]ations ( a/ronom]s4 ,x %\ld h no ma*9]y1 no pivots1 axes1 circles1 clocks1 or o!r p>aph]nalia ( ! usual equatorial telescope4 ,all we want is a v heavy /one pi]1 ) a telescope tube firmly fa/5$ to x ?r\gh\t its entire l5g?4 ,! top ( ! pi] hav+ be5 cut to ! prop] angle ( ! pole's elevation1 & ! telescope cem5t$ d[n1 ev]y?+ is complete f ! in/rum5tal side2 & j su* an in/rum5t z ?is is n[ ready = use at ,hels+=s4 ,! late ,miss ,ca?>9e ,wolfe ,bruce1 ( ,new ,york1 0 mu* int]e/$ 9 ! writ]'s propos$ pol> inve/igations1 & 9 ,octob]1 #ahih1 %e contribut$ funds = ! con/ruction ( ! new telescope1 & ! ,russian au?orities h g5]\sly und]tak5 ! exp5se ( a build+ to hold ! in/rum5t & ! granite f\ndation ^u :i* x re/s4 ,photographs are n[ be+ secur$ ) ! new in/rum5t1 & !y w be s5t to ,columbia ,univ]sity1 ,new ,york1 = measurem5t & discussion4 ,x is hop$ t !y w c>ry out ! promise ( ! prelim9>y photographs made 9 #ahie ) a less suitable telescope ( ! ord9>y =m4 ,,! ,,moon ,,hoax ,! public attitude t[>d matt]s sci5tific is "o ( ! my/]ies ( our "t4 ,x c be describ$ be/ by ! s+le ^w1 ,cr$ulity2 simple1 absolute cr$ulity4 ,p]fect confid5ce is ! mo/ rem>kable *>act]i/ic ( ?is unbeliev+ age4 ,no *>latan1 necromanc]1 or a/rolog] ( ?ree c5turies ago comm&$ m respectful att5tion ?an does 8 successor ( to-day4 ,any p]son c be a sci5tific au?ority2 he has b to call himself by t title1 & ev]yone w give him respectful att5tion4 ,num]\s in/ances c be adduc$ f ! exp]i5ce ( v rec5t ye>s to %[ h[ true are ^! rem>ks4 ,we h _h ! ,keeley motor & ! liquid-air p[] s*emes = mak+ some?+ out ( no?+4 ,extract+ gold f sea-wat] has be5 duly h]ald$ on sci5tific au?ority z an easy s\rce ( fabul\s weal? = ! million4 ,h>d-head$ bus9ess m5 n only believe 9 su* ?+s1 b actually inve/ 9 !m _! mo/ valu$ possession1 capital4 ,v5d]s ( no/rums & propriet>y m$ic9es acquire weal? z if by magic1 ?\gh x ne$s b a mom5t's reflection to realize t ^! p]sons _c possibly be 9 possession ( any drugs1 or secret me?ods ( comp\nd+ drugs1 t are unkn[n to sci5tific *emi/s4 ,if ! _w1 !n1 w p]si/5tly intru/ its heal? & weal? into ! safe-keep+ ( *>latans1 :at c we expect :5 ?+s suppos$ly ( f> less value are at /ake8 ,! fam\s ,moon ,hoax1 z we n[ call x1 is truly a classic piece ( ly+4 ,?\gh x dates f z long ago z #ahce1 x has nev] _h an equal z a piece ( mod]n j\rnalism4 ,no?+ c\ld be m useful ?an to recall x to public att5tion at lea/ once e decade2 = x tea*es an important lesson t ne$s to be it]at$ aga9 & aga94 ,on ,novemb] #ac1 #ahcc1 ,sir ,john ,h]s*el emb>k$ on ! ,m\nt/u>t ,elph9/one1 b\nd = ! ,cape ( ,good ,hope4 ,he took ) him a collection ( a/ronomical in/rum5ts1 ) :i* he int5d$ to /udy ! heav5s ( ! s\!rn hemisph]e1 & ?us ext5d 8 fa!r's great "w to ! s\? pol> />s4 ,an e>ne/ /ud5t ( a/ronomy1 he ask$ no bett] ?an to be left 9 peace to seek ! tru? 9 8 own fa%ion4 ,little did he ?9k t 8 exp$ition w\ld be made ! basis = a fabrication ( alleg$ a/ronomical discov]ies de/9$ to />tle a hemisph]e4 ,yet t is precisely :at happ5$4 ,"s "t ab\t ! middle ( ! ye> #ahce ! ,new ,york ,sun began ! publication ( c]ta9 articles1 purport+ to give an acc\nt ( ,great ,a/ronomical ,discov]ies1 lately made by ,sir ,john ,h]s*el at ! ,cape ( ,good ,hope4 ,x 0 alleg$ t ^! articles 7 tak5 f a supplem5t to ! ,ed9burgh ,j\rnal ( ,sci5ce2 yet !re is no d\bt t !y 7 manufactur$ entirely 9 ! ,unit$ ,/ates1 & probably 9 ,new ,york4 ,! hoax beg9s at once 9 a gr&iloqu5t /yle1 calculat$ to attract popul> att5tion1 & well fitt$ to ! m>vels ab\t to be relat$4 ,"h is an introductory rem>k1 z a specim53 ,x has be5 poetically said t ! />s ( heav5 are ! h]$it>y regalia ( man z ! intellectual sov]eign ( ! animal creation4 ,he may n[ fold ! zodiac ar\nd him ) a l(ti] consci\sness ( 8 m5tal supremacy4 ,!n foll[s a circum/antial & highly plausible acc\nt ( ! mann] 9 :i* e>ly & exclusive in=mation 0 obta9$ f ! ,cape4 ,?is 01 ( c\rse1 important 9 ord] to make p believe 9 ! g5u95ess ( ! :ole2 b we pass at once to ! m int]e/+ acc\nt ( ,h]s*el's suppos$ in/rum5t4 ,no?+ c\ld be m skilful ?an ! way 9 :i* an air ( tru? is ca/ ov] ! com+ acc\nt ( m>vell\s discov]ies by expla9+ 9 detail ! con/ruction ( ! imag9>y ,h]s*elian in/rum5t4 ,sir ,john is suppos$ to h _h an int]e/+ conv]sation 9 ,engl& ) ,sir ,david ,brew/]1 ^u ! m]its ( "s +5i\s sugge/ion by ! latt]1 9 8 article on optics 9 ! ,ed9burgh ,encyclopdia 7p4 #fdd71 = improvem5ts 9 ! ,newtonian reflectors4 ,! exact ref]5ce to a p>ticul> page is "h q delightful4 ,aft] "s fur!r talk1 ! conv]sation became direct$ to t all-inv9cible enemy1 ! paucity ( light 9 p[]ful magnifi]s4 ,aft] a few mom5ts' sil5t ?\ght1 ,sir ,john diffid5tly inquir$ :e!r x w\ld n be possible to effect a transfusion ( artificial light ?r\gh ! focal object ( vision6 ,sir ,david1 some:at />tl$ at ! orig9ality ( ! idea1 paus$ a:ile1 & !n hesitat+ly ref]r$ to ! refrangibility ( rays1 & ! angle ( incid5ce4444 ,sir ,john cont9u$1 ',:y _c ! illum9at$ microscope1 say ! hydro-oxyg51 be appli$ to r5d] di/9ct1 &1 if necess>y1 ev5 to magnify ! focal object8' ,sir ,david sprang f 8 *air 9 an ec/asy ( conviction1 & leap+ half-way to ! ceil+1 exclaim$1 ',?\ art ! man4' ,?is absurd imag9>y conv]sation conta9s no?+ b an assemblage ( optical j>gon1 put toge!r )\t ! slighte/ int5tion ( convey+ any intelligible mean+ to sci5tific p4 ,yet x 0 well adapt$ to deceive ! public2 & we %\ld n be surpris$ if x w\ld be cr$it$ by _m newspap] read]s to-day4 ,! au?ors g on to expla9 h[ money 0 rais$ to build ! new in/rum5t1 & !n describe ,h]s*]s emb>kation & ! difficulties connect$ ) transport+ 8 gigantic ma*9es to ! place select$ = ! obs]v+ /ation4 ,sir ,john accompli%$ ! asc5t to ! pla9s by means ( two relief teams ( ox51 ( eighte5 ea*1 9 ab\t f\r days1 &1 aid$ by sev]al companies ( ,dut* boors sic1 proce$$ at once to ! erect+ ( 8 gigantic fabric4 ,! place really select$ by ,h]s*el _c be describ$ bett] ?an 9 8 own words1 conta9$ 9 a g5u9e lett] dat$ ,janu>y #ba1 #ahce3 ,a p]fect p>adise 9 ri* & magnific5t m\nta9 sc5]y1 %elt]$ f all w9ds4444 ,i mu/ res]ve = my next all description ( ! gorge\s display ( fl[]s :i* adorn ?is spl5did c\ntry1 z well z ! a/oni%+ brilliancy ( ! con/ellations4 ,! au?or ( ! hoax c\ld h _h no k ( ,h]s*]s real location1 z describ$ 9 ?is lett]4 ,! pres5t writ] c be> witness to ! correctness ( ,h]s*el's words4 ,feldhaus5 is truly an ideal seclud$ spot = a/ronomical /udy4 ,a small obelisk "u ! %e] cliff ( f>-fam$ ,table ,m\nta9 n[ m>ks ! site ( ! great reflect+ telescope4 ,"h ,h]s*el c>ri$ on 8 scrut9y ( ! ,s\!rn skies4 ,he obs]v$ #a1bjb d\ble />s & #a1gjh nebul & clu/]s1 ( :i* only #dci 7 already kn[n4 ,he /udi$ ! fam\s ,magellanic cl\ds1 & made ! fir/ c>eful draw+s ( ! keyhole nebula 9 ! con/ellation ,argo4 ,v rec5t rese>*es ( ! pres5t royal a/ronom] at ! ,cape h %[n t *anges ( import h c]ta9ly tak5 place 9 ?is nebula s9ce ,h]s*el's "t1 :5 a sudd5 blaz+ up ( ! wond]ful /> ,eta ,argus 0 se5 )9 ! nebula4 ,?is object has1 p]haps1 und]gone m rem>kable *anges ( light ?an any o!r /> 9 ! heav5s4 ,x is z ?\gh !re 7 "s va/ conflagration at "w1 n[ blaz+ into inc&esc5ce1 & aga9 s9k+ almo/ into invisibility4 ,9 #ahdc ,macle> e/imat$ ! brilliancy ( ,eta to be ab\t equal to t ( ,sirius1 ! brighte/ /> 9 ! :ole sky4 ,lat] x dim9i%$ 9 light1 & _c be se5 to-day ) ! nak$ eye1 ?\gh ! late/ telescopic obs]vations indicate t x is aga9 beg9n+ to bright54 ,su* 0 ,h]s*el's quiet /udy ( 8 belov$ sci5ce1 9 gl>+ contra/ to ! suppos$ discov]ies ( ! ,hoax4 ,"h are a few ?+s alleg$ to h be5 se5 on ! moon4 ,! fir/ "t ! in/rum5t 0 turn$ ^u our satellite ! field ( view 0 cov]$ ?r\gh\t its entire area ) a beautifully di/9ct & ev5 vivid repres5tation ( basaltic rock4 ,!re 7 =e/s1 too1 & wat]1 fair] %ores nev] angels coa/$ on a t\r ( pleasure4 ,a bea* ( brilliant :ite s&1 girt ) wild ca/ellat$ rocks1 app>5tly ( gre5 m>ble4 ,!re 0 animal life z well2 we beheld cont9u\s h]ds ( br[n quadrup$s1 hav+ all ! ext]nal *>act]i/ics ( ! bison1 b m dim9utive ?an any species ( ! bos g5us 9 our natural hi/ory4 ,!re 0 a k9d ( beav]1 t c>ries its "y 9 its arms l a human be+1 & lives 9 huts4 ,f ! appe>ance ( smoke 9 ne>ly all ( !m1 !re is no d\bt ( its 7! beav]'s7 be+ acqua9t$ ) ! use ( fire4 ,f9ally1 z 01 ( c\rse1 unavoidable1 human creatures 7 discov]$4 ,:il/ gaz+ 9 a p]spective ( ab\t half a mile1 we 7 ?rill$ ) a/oni%m5t to p]ceive f\r successive flocks ( l>ge-w+$ creatures1 :olly unlike any k9d ( birds1 desc5d ) a sl[1 ev5 motion f ! cliffs on ! we/]n side1 & alight ^u ! pla94444 ,c]ta9ly !y 7 l human be+s1 & _! attitude 9 walk+ 0 bo? erect & dignifi$4 ,we h n space to give m ext5d$ extracts f ! hoax1 b we ?9k ! above specim5s w %[ h[ deceptive ! :ole ?+ 04 ,! r>e repr9t f :i* we h extract$ our quotations conta9s also "s int]e/+ ,op9ions ( ! ,am]ican ,press ,respect+ ! ,=ego+ ,discov]y4 ,! ,daily ,adv]tis] said3 ,no article1 we believe1 has appe>$ = ye>s1 t w comm& s g5]al a p]usal & publication4 ,sir ,john has add$ a /ock ( k to ! pres5t age t w immortalize 8 "n & place x high on ! page ( sci5ce4 ,! ,m]cantile ,adv]tis] said3 ,discov]ies 9 ! ,moon4--,we comm5ce to-day ! publication ( an int]e/+ article :i* is /at$ to h be5 copi$ f ! ,ed9burgh ,j\rnal ( ,sci5ce1 & :i* made its fir/ appe>ance "h 9 a contempor>y j\rnal ( ?is city4 ,x appe>s to c>ry intr9sic evid5ce ( be+ an au!ntic docum5t4 ,_m o!r simil> extracts are giv54 ,! ,new ,york ,ev5+ ,po/ did n fall into ! trap4 ,! ,ev5+ ,po/'s rem>ks 7 z foll[s3 ,x is q prop] t ! ,sun %\ld be ! means ( %$d+ s mu* light on ! ,moon4 ,t !re %\ld be w+$ p 9 ! moon does n /rike u z m wond]ful ?an ! exi/5ce ( su* a race ( be+s on ! e>?2 & t !re does or did exi/ su* a race re/s on ! evid5ce ( t mo/ v]aci\s ( voyag]s & circum/antial ( *ronicl]s1 ,pet] ,wilk9s1 ^: celebrat$ "w n only gives an acc\nt ( ! g5]al appe>ance & habits ( a mo/ int]e/+ tribe ( fly+ ,indians1 b also ( all ^? m delicate & engag+ traits :i* ! au?or 0 enabl$ to discov] by reason ( ! conjugal relations he ent]$ into ) "o ( ! females ( ! w+$ tribe4 ,we %all limit our extracts f ! contempor>y press to ! few quotations "h giv51 hop+ t en\gh has be5 said to direct att5tion once m to t important subject1 ! ,possibility ( ,be+ ,deceiv$4 ,,! ,,sun',s ,,de/9ation ,?ree g5]ations ( m5 h come & gone s9ce ! ,m>quis de ,laplace /ood be=e ! ,academy ( ,france & gave 8 demon/ration ( ! p]man5t /ability ( our sol> sy/em4 ,!re 0 "o significant fault 9 ,newton's sup]bly simple conception ( an et]nal law gov]n+ ! _w 9 :i* we live4 ,! labors ( ma!maticians foll[+ him _h %[n t ! planets mu/ trace out pa?s 9 space ^: =m c\ld be det]m9$ 9 advance ) un]r+ c]ta9ty by ! aid ( ,newton's law ( gravitation4 ,b !y prov$ j z conclusively t ^! planet>y orbits1 z !y are call$1 c\ld n ma9ta9 indef9itely ! same %apes or positions4 ,sl[ inde$ might be ! *anges !y 7 de/9$ to und]go2 sl[1 b sure1 ) t sur5ess belong+ to cele/ial sci5ce alone4 ,& s m5 ask$3 ,has ?is magnific5t sol> sy/em be5 built ^u a scale s gr&1 be5 put 9 op]ation subject to a law sublime 9 its v simplicity1 only to *ange & *ange until at l5g? x %all lose e semblance ( its =m] self1 & end1 p]haps1 9 *aos or ext9ction8 ,laplace 0 able to answ] confid5tly1 ,no4 ,nor 0 8 answ] c\*$ 9 ! en?usia/ic language ( unbalanc$ !ori/s :o "w by ! aid ( imag9ation alone4 ,bas$ ^u ! irrefragable logic ( correct ma!matical reason+1 & clad 9 ! sob] g>b ( ma!matical =mul1 8 results c>ri$ conviction to m5 ( sci5ce ! _w ov]4 ,s 0 x demon/rat$ t *anges 9 our sol> sy/em are surely at "w1 & %all cont9ue = ne>ly c\ntless ages2 yet j z surely w !y be rev]s$ at la/1 & ! sy/em w t5d to return aga9 to its orig9al =m & condition4 ,! objection t ! ,newtonian law meant ultimate dissolution ( ! _w 0 ?us de/roy$ by ,laplace4 ,f t day =w>d ! law ( gravitation has be5 accept$ z hold+ sway ov] all ph5om5a visible )9 our planet>y _w4 ,! intricacies ( our own sol> sy/em be+ ?us illum9$1 ! re/less activity ( ! human intellect 0 /imulat$ to se>* beyond = new problems & new my/]ies4 ,ev5 m fasc9at+ ?an ! movem5ts ( our sun & planets are all ^? que/ions t relate to ! clu/]$ /ell> cong]ies hang+ susp5d$ )9 ! deep vault ( night4 ,does ! same law ( gravitation ca/ its magic spell ov] t hazy cl\d ( ,pleiades1 b9d+ !m1 l ourselves1 ) bonds indissoluble8 ,:o %all answ]1 yes or no8 ,we c only say t a/ronom]s h z yet b /epp$ ^u ! ?re%old ( ! univ]se1 & fix$ ! telescope's great eye ^u t :i* is )94 ,let u !n beg9 by rem9d+ ! read] :at is meant by ! ,newtonian law ( gravitation4 ,x appe>s all ?+s possess ! rem>kable prop]ty ( attract+ or pull+ ea* o!r4 ,newton decl>$ t all sub/ances1 solid1 liquid1 or ev5 gase\s--f ! massive cliff ( rock d[n to ! invisible air--all matt] c no m help pull+ ?an x c help exi/+4 ,8 law fur!r =mulates c]ta9 conditions gov]n+ ! mann] 9 :i* ?is gravitational attraction is ex]t$2 b ^! are m]e matt]s ( detail2 int]e/ c5tres ab\t ! my/]i\s fact ( attraction itself4 ,h[ c "o ?+ pull ano!r ) no connect+ l9k ?r\gh :i* ! pull c act8 ,j "h we t\* ! po9t t has nev] yet be5 expla9$4 ,nature )holds f sci5ce h] ultimate secrets4 ,!y t h pond]$ longe/1 t h desc5d$ f>!/ ( all m5 into ! cle> well ( k1 h done s b to s\nd ! dep?s beyond1 nev] t\*+ bottom4 ,?is inability ( ours1 to give a good physical explanation ( gravitation1 has l$ c]ta9 mak]s ( p>adoxes to d\bt or ev5 d5y t !re is any su* ?+4 ,b1 =tunately1 we h a simple laboratory exp]im5t t helps u4 ,unexpla9$ x may ev] rema91 b t !re c be attraction betwe5 physical objects connect$ by no visible l9k is prov$ by ! behavior ( an ord9>y magnet4 ,place a small piece ( /eel or iron ne> a magnetiz$ b>1 & x w at once be s /rongly attract$ t x w actually fly to ! magnet4 ,anyone :o has se5 ?is simple exp]im5t c nev] aga9 d5y ! possibility1 at lea/1 ( ! law ( attraction z /at$ by ,newton4 ,its possibility once admitt$1 ! fact t x c pr$ict ! motions ( all ! planets1 ev5 d[n to _! m9ute/ details1 trans=ms ! possibility ( its tru? into a c]ta9ty z /rong z any human c]ta9ty c ev] be4 ,b ?is demon/ration ( ,newton's law is limit$ /rictly to ! sol> sy/em itself4 ,we may1 inde$1 reason by analogy1 & take = grant$ t a law :i* holds )9 our imm$iate neighborhood is extremely likely to be true also ( ! entire visible univ]se4 ,b m5 ( sci5ce are loa? to reason ?us2 & h5ce ! fasc9ation ( rese>*es 9 cosmic a/ronomy4 ,analogy po9ts out ! pa?4 ,! a/ronom] is n sl[ to foll[2 b he seeks ev] to e/abli% ^u incontrov]tible evid5ce ^? tru?s :i* at fir/ only 8 d>+ imag9ation _h l$ him to half suspect4 ,if we are to ext5d ! law ( gravitation to ! utmo/1 we mu/ be c>eful to consid] ! law itself 9 its mo/ complete =m4 ,a heav5ly body l ! sun is (t5 said to gov]n ! motions ( its family ( planets2 b su* a /atem5t is n /rictly accurate4 ,! gov]n+ body is no despot2 'tis an abject slave ( law & ord]1 z mu* z ! t9ie/ ( att5dant planets4 ,! action ( gravitation is mutual1 & no cosmic body c attract ano!r )\t be+ itself 9 turn subject to t o!r's gravitational action4 ,if !re 7 9 our sol> sy/em b two bodies1 sun & planet1 we %\ld f9d ea* "o pursu+ a pa? 9 space "u ! influ5ce ( ! o!r's attraction4 ,^! two pa?s or orbits w\ld be oval1 & if ! sun & planet 7 equally massive1 ! orbits w\ld be exactly alike1 bo? 9 %ape & size4 ,b if ! sun 7 f> l>g] ?an ! planet1 ! orbits w\ld /ill be simil> 9 =m1 b ! "o trav]s$ by ! l>g] body w\ld be small4 ,= x is n reasonable to expect a little planet to keep ! big sun mov+ ) a velocity z great z t d]iv$ by itself f ! attraction ( ! l>g] orb4 ,:5ev] ! prepond]ance ( ! l>g] body is extremely great1 its orbit w be correspond+ly insignificant 9 size4 ,?is is 9 fact ! case ) our own sun4 ,s massive is x 9 comp>ison ) ! planets t ! orbit is too small to reveal its actual exi/5ce )\t ! aid ( our mo/ ref9$ in/rum5ts4 ,! pa? trac$ out by ! sun's c5tre w\ld n fill a space z l>ge z ! sun's own bulk4 ,nev]!less1 true orbital motion is !re4 ,s we may conclude t z a necess>y consequ5ce ( ! law ( gravitation e object )9 ! sol> sy/em is 9 motion4 ,to say t planets revolve ab\t ! sun is to neglect z unimportant ! small orbit ( ! sun itself4 ,?is may be suffici5tly accurate = ord9>y purposes2 b x is unque/ionably necess>y to neglect no factor1 h[ev] small1 if we propose to ext5d our reason+ to a consid]ation ( ! /ell> univ]se4 ,= we %all !n h to deal ) sy/ems 9 :i* ! planets are ( a size comp>able ) ! sun2 & 9 su* sy/ems all ! orbits w also be ( comp>atively equal importance4 ,ma!matical analysis has d]iv$ ano!r fact f discussion ( ! law ( gravitation :i*1 p]haps1 transc5ds 9 simple gr&eur ev]y?+ we h z yet m5tion$4 ,x matt]s n h[ great may be ! numb] ( massive orbs ?read+ _! c\ntless int]lac+ curv$ pa?s 9 space1 !re yet mu/ be 9 e cosmic sy/em "o s+le po9t immovable4 ,?is po9t is call$ ! ,c5tre ( ,gravity4 ,if x %\ld s happ5 t 9 ! beg9n+ ( ?+s1 "s p>ticle ( matt] 7 situat$ at ?is c5tre1 !n w\ld t atom ev] rema9 unmov$ & imp]turbable ?r\gh\t all ! successive vicissitudes ( cosmic evolution4 ,x is d\btful :e!r ! m9d ( man c =m a conception ( any?+ gr&] ?an su* an immovable atom )9 ! my/]i\s intricacies ( cosmic motion4 ,b 9 g5]al1 we _c suppose t ! c5tres ( gravity 9 ! v>i\s /ell> sy/ems are really occupi$ by actual physical bodies4 ,! c5tre may be a m]e ma!matical po9t 9 space1 situat$ among ! sev]al bodies compos+ ! sy/em1 b1 nev]!less1 end[$1 9 a c]ta9 s5se1 ) ! same rem>kable prop]ty ( relative immobility4 ,hav+ ?us def9$ ! c5tre ( gravity 9 its relation to ! con/itu5t p>ts ( any cosmic sy/em1 we c pass easily to its *>act]i/ic prop]ties 9 connection ) ! int]-relation ( /ell> sy/ems ) "o ano!r4 ,x c be prov$ ma!matically t our sol> sy/em w pull ^u di/ant />s j z ?\gh ! sun & all ! planets 7 conc5trat$ into "o va/ sph]e hav+ its c5tre 9 ! c5tre ( gravity ( ! :ole4 ,x is ?is prop]ty ( ! c5tre ( gravity :i* makes x pre-em95tly important 9 cosmic rese>*es4 ,=1 :ile we "k t c5tre to be at re/ relatively to all ! planets 9 ! sy/em1 x may1 nev]!less1 9 its quality z a sort ( conc5trat$ ess5ce ( !m all1 be mov+ swiftly ?r\gh space "u ! pull ( di/ant />s4 ,9 t case1 ! att5dant bodies w g ) x--b !y w pursue _! evolutions )9 ! sy/em1 all unconsci\s t ! c5tre ( gravity is c>ry+ !m on a f> wid] circuit4 ,:at is ! nature ( t circuit8 ,?is "q has be5 = _m ye>s ! subject ( e>ne/ /udy by ! cle>e/ m9ds among a/ronom]s4 ,! greate/ difficulty 9 ! way is ! comp>atively brief p]iod dur+ :i* m5 h be5 able to make a/ronomical obs]vations ( precision4 ,space & "t are two conceptions t transc5d ! p[]s ( def9ition possess$ by any man4 ,b we c at lea/ =m a notion ( h[ va/ is ! ext5t ( "t1 if we rememb] t ! p]iod cov]$ by man's writt5 records is regi/]$ b z a s+le mom5t ^u ! great revolv+ dial ( heav5's dome4 ,"o hundr$ & fifty ye>s h elaps$ s9ce ,james ,bradley built ! f\ndations ( mod]n sid]eal a/ronomy ^u 8 ma/]ly s]ies ( obs]vations at ! ,royal ,obs]vatory ( ,gre5wi*1 9 ,engl&4 ,yet s sl[ly d ! movem5ts ( ! />s unroll !mselves ^u ! firmam5t1 t ev5 to ?is day no "o ( !m has be5 se5 by m5 to trace out m ?an an inf9itesimal fraction ( its de/9$ pa? ?r\gh ! voids ( space4 ,travell]s ^u a railroad _c tell at any giv5 mom5t :e!r !y are mov+ 9 a /raight l9e1 or :e!r ! tra9 is turn+ ^u "s curve ( huge size4 ,! ,/4 ,go?>d railway has sev]al s-call$ corkscrew tunnels1 )9 :i* ! rails make a complete turn 9 a spiral1 ! tra9 f9ally em]g+ f ! tunnel at a po9t almo/ v]tically ov] ! entrance4 ,9 ?is way ! tra9 is lift$ to a high] level4 ,pass5g]s are wont to amuse !mselves :ile 9 ^! tunnels by wat*+ ! ne$le ( an ord9>y pocket-compass4 ,?is ne$le1 ( c\rse1 always po9ts to ! nor?2 & z ! tra9 turns ^u its curve1 ! ne$le w make a complete revolution4 ,b ! pass5g] c\ld n "k )\t ! compass t ! tra9 0 n mov+ 9 a p]fectly /raight l9e4 ,j s we pass5g]s on ! e>? are unaw>e ( ! k9d ( pa? we are trav]s+1 until1 l ! compass1 ! a/ronom]'s in/rum5ts %all reveal to u ! tru?4 ,b z we h se51 a/ronomical obs]vations ( precision h n z yet ext5d$ ?r\gh a p]iod ( "t correspond+ to ! few m9utes dur+ :i* ! ,/4 ,go?>d travell] wat*es ! compass4 ,we are /ill 9 ! d>k1 & d n "k z yet :e!r mank9d %all la/ long en\gh ^u ! e>? to see ! compass ne$le make its revolution4 ,we are compell$ to believe t ! motion 9 space ( our sun is progress+ ^u a curv$ pa?2 b s f> z precise obs]vations all[ u to speak1 we c b say t we h z yet mov$ ?r\gh an inf9itesimal elem5t only ( t mighty curve4 ,h[ev]1 we "k ! po9t ^u ! sky t[>d :i* ?is t9y elem5t ( our pa? is direct$1 & we h an approximate k ( ! spe$ at :i* we move4 ,m ?an a c5tury ago ,sir ,william ,h]s*el 0 able to fix r\ghly :at we call ! apex ( ! sun's way 9 space1 or ! po9t among ! />s t[>d :i* t way is = ! mom5t direct$4 ,we say = ! mom5t1 b we mean t mom5t ( :i* ,bradley saw ! beg9n+ 9 #agej1 & ^u ^: end no man ( ^? n[ liv+ %all ev] look4 ,h]s*el f\nd t a comp>ison ( old /ell> obs]vations seem$ to indicate t ! />s 9 a c]ta9 "p ( ! sky 7 op5+ out1 z x 71 & t ! con/ellations 9 ! opposite "p ( ! heav5s seem$ to be draw+ 91 or becom+ small]4 ,!re c be b "o reasonable explanation ( ?is4 ,we mu/ be mov+ t[>d t "p ( ! sky :]e ! />s are sep>at+4 ,j s a man wat*+ a regim5t ( soldi]s approa*+1 w see at fir/ only a confus$ body ( m52 b z !y come ne>]1 ! individual soldi]s w seem to sep>ate1 until at l5g? ea* "o is se5 di/9ct f all ! o!rs4 ,h]s*el fix$ ! position ( ! apex at a po9t 9 ! con/ellation ,h]cules4 ,! mo/ rec5t inve/igations ( ,newcomb & o!rs h1 on ! :ole1 v]ifi$ ,h]s*el's conclusions4 ,) ! intuitive p[] ( r>e g5ius1 ,h]s*el _h be5 able to sift tru? out ( error4 ,! obs]vational data at 8 disposal w\ld n[ be call$ rude1 b !y disclos$ to ! scrut9y ( 8 acute und]/&+ ! g]m ( tru? t 0 9 !m4 ,lat] inve/igators h increas$ ! precision ( our k1 until we c n[ say t ! pres5t direction ( ! sol> motion is kn[n )9 v n>r[ limits4 ,a t9y circle might be drawn on ! sky1 to :i* an a/ronom] might po9t 8 h& & say3 ,yond] little circle conta9s ! goal t[>d :i* ! sun & planets are ha/5+ to-day4 ,ev5 ! spe$ ( ?is motion has be5 subject$ to measurem5t1 & f\nd to be ab\t t5 miles p] second4 ,! objective po9t & ! rate ( motion ?us /at$1 exact sci5ce holds h] peace4 ,"h g5u9e k /ops2 & we c proce$ fur!r only by ! aid ( t imag9ation :i* m5 ( sci5ce ne$ to curb at e mom5t4 ,b let no "o ?9k t ! sun w ev] rea* ! s-call$ apex4 ,to d s w\ld mean cosmic motion ^u a /raight l9e1 :ile e consid]ation ( cele/ial me*anics po9ts to motion ^u a curve4 ,:5 %all we turn suffici5tly ^u t curve to detect its b5d+8 ',tis a problem we mu/ leave z a ri* h]itage to lat] g5]ations t are to foll[ u4 ,! vision>y !ori/'s notion ( a great c5tral sun1 controll+ our own sun's way 9 space1 mu/ be dismiss$ z f> too d>+4 ,b = su* a c5tral sun we may sub/itute a c5tral c5tre ( gravity belong+ to a great sy/em ( :i* our sun is b an insignificant memb]4 ,!n we rea* a conception t has lo/ no?+ 9 ! gr&eur ( its simplicity1 & is yet 9 accord ) ! probabilities ( sob] me*anical sci5ce4 ,we cease to be a lonely _w1 & /ret* out ! bonds ( a common relation%ip to yond] />s )9 ! firmam5t4 ,,index ,,page ,airy1 ,a/ronom] ,royal1 #a ,allis1 photographs comet1 #aja ,&rom$a nebula1 #bh tempor>y />1 #bh1 #bi1 #de ,apex1 ( sol> motion1 expla9$1 #bba ,aquila1 con/ellation1 tempor>y /> 91 #dj ,arctic regions1 position ( pole 91 #aid ,argo1 con/ellation1 v>iable /> 91 #bje ,association1 int]national geodetic1 #aci ,a/]oids1 fir/ discov]y by ,piazzi1 #ei1 #ajf discov]y by photography1 #fd gr\p (1 #fc photography (1 inv5t$ by ,wolf1 #ajd ,a/ronom]1 royal1 #a work+1 description (1 #aeb ,,a/ronom]',s ,,pole1 ,,!1 #ahd ,a/ronomy1 j\rnali/ic1 #agf practical uses (1 #aab ,atmosph]ic refraction1 expla9$1 #aic ,axis1 ( figure ( ! e>?1 #acf ( rotation ( ! e>?1 #acf pol>1 ( telescope1 #agc ,b>n>d1 discov]s satellite ( ,jupit]1 #ea ,bessel1 measures ,pleiades1 #ae ,bond1 discov]s crape r+ ( ,saturn1 #add ,bradley1 obs]ves at ,gre5wi*1 #bai ,brahe1 ,ty*o1 8 tempor>y />1 #dj ,bruce1 end[s pol> photography1 #aig ,campbell1 obs]ves ,pole-/>1 #ah ,cape ( ,good ,hope1 obs]vatory1 photography at1 #aja telescope1 #agj1 #agd ,capriccio1 ,galileo's1 #ee ,cass9i1 %[s ,saturn's r+s to be d\ble1 #add ,cassiopeia1 tempor>y /> 91 #dj ,cele/ial pole1 #ahd ,c5tral sun !ory1 #bbc ,c5tre ( gravity1 #bag ,*>t-room1 on %ip-bo>d1 #e ,*ronomet]1 inv5tion (1 #h ,circle1 m]idian1 expla9$1 #ahi ,cl]k ,maxwell1 discusses ,saturn's r+s1 #adf ,clock1 affect$ by temp]ature1 #aag affect$ by b>ometric pressure1 #aag a/ronomical1 #aae a/ronomical1 h[ m\nt$1 #aaf a/ronomical1 its dial1 #aaf error (1 det]m9$ ) transit1 #aah jewell]'s regulator1 #aad ( telescope1 #age ,clu/]s ( />s1 photography (1 #ih ,columbia ,univ]sity ,obs]vatory1 latitude obs]vations1 #aci pol> photography1 #aif ,common1 8 reflect+ telescope1 #cb ,confusion ( dates1 9 ,pacific ,ocean1 #abe ,congress ( ,a/ronom]s1 ,p>is1 #ahhg1 #ajb ,con/ellations1 #afb ,control1 m\se1 = photography1 #hh ,cop]nican !ory ( univ]se1 #ec1 #ef demon/ration1 #id ,corkscrew tunnels1 #bbj ,crape r+ ( ,saturn1 #add ,cumulative effect1 9 photography1 #hd ,date1 confusion (1 9 ,pacific ,ocean1 #abe ,date-l9e1 int]national1 expla9$1 #abf ,developm5t ( photograph1 #ha ,dial1 ( a/ronomical clock1 #aaf ,dialogue ( ,galileo1 #ec ,diff]5ces ( "t1 expla9$1 #aba ,directions1 telescopic measurem5t (1 #ba ,directory ( ! heav5s1 #ajc ,di/ance1 ( light-s\rce 9 photography1 #hc ( />s1 #id1 #ajf1 #aeh ( ,sun1 #fg1 #ig1 #ajf ,donn]1 pol> photography1 #aie ,d\ble telescopes1 = photography1 #hf ,e>?1 motions ( its pole1 #aca rotation (1 #acf1 #afb1 #aga1 #ahd %ape (1 #ace ,eclipses1 photography (1 #aji ,elk91 measures ,pleiades1 #ae ,equatorial telescope1 expla9$1 #agj ,eros1 discov]$ by ,witt1 #ff1 #aje its importance1 #fg ,error ( clock1 det]m9$ by transit1 #aah ,exposure1 l5g? (1 9 photography1 #hd ,feldhaus51 ,h]s*el's obs]vatory ne> ,capet[n1 #bjd ,fiji ,isl&s1 _! date1 #abf ,fix$ pol> telescope1 #aig ,foll[+ ! />s1 #hh1 #agc ,f\r-day cycle ( pole-/>1 #bd ,france1 outside "t-zone sy/em1 #abi ,fundam5tal longitude m]idian1 #abd ,,galileo1 #dg & ! ,*ur*1 #dh discov]ies (1 #di obs]ves ,saturn1 #ada ,galle1 discov]s ,neptune1 #fa ,gauss1 computes fir/ a/]oid orbit1 #fj ,gauti]1 ,p>is1 con/ructs big telescope1 #agi ,geodetic ,association1 int]national1 #aci ,geography1 maps1 a/ronomical side (1 #aab ,geology1 pol> motion 91 #aca ,gill1 photographs comet1 #ajj ,gilliss1 at ,naval ,obs]vatory1 ,wa%+ton1 #afi ,goldsbor\gh1 at ,naval ,obs]vatory1 ,wa%+ton1 #afi ,gr&e ,lunette1 ,p>is1 #aijj1 #agf1 #ahj ,gravitation1 #ac 9 ,pleiades1 #ad1 #bab law (1 ,newton's1 #bab ,gravity1 c5tre (1 #bag ,gre5wi*1 orig9 ( longitudes1 #g1 #abd "t1 #g ,groombridge1 ,engli% a/ronom]1 #a ,h>rison1 inv5tor ( *ronomet]1 #h ,head1 ( heliomet]1 #aef ,heidelb]g1 photography at1 #ajd ,,heliomet]1 #aeb head (1 #aef h[ us$1 #aeg pr9ciple (1 #aed scales (1 #aeh semi-l5ses (1 #aee ,hels+=s obs]vatory1 pol> photography at1 #aie ,h5ry1 measures ,pleiades1 #aa1 #ag ,h]cules1 con/ellation1 sol> motion t[>d1 #bbb ,h]s*el1 discov]s apex ( sol> motion1 #bba discov]s ,uranus1 #ei1 #ada ,john1 ! moon hoax1 #bjj ,hipp>*us1 discov]s precession1 #ahf e>ly />-catalogue1 #ba1 #ci inv5ts /> magnitudes1 #ia ,huyg5s1 ann\nces r+s ( ,saturn1 #adb 8 logogriph1 #adc ,ice-cap1 ( ,e>?1 #aca ,index ,librorum ,prohibitorum1 #ec ,int]national1 date-l9e1 expla9$1 #abf geodetic association1 #aci ,int]-/ell> motion1 9 clu/]s1 #ih 9 ,pleiades1 #ad ,isl&s ( ,pacific1 _! longitude & "t1 #abe ,japan1 latitude /ation 91 #aci ,jewell]s' correct "t1 #aba ,j\rnali/ic a/ronomy1 #agf ,jupit]'s satellites1 discov]$ by ,galileo1 #ej discov]$ by ,b>n>d1 #ea ,keel]1 obs]ves ,saturn's r+s1 #adj1 #adg1 #aej photographs nebul1 #cb ,keyhole nebula1 #bje ,lamb]t1 det]m9es longitude ( ,wa%+ton1 #afh ,laplace1 discusses ,saturn's r+s1 #adf nebul> hypo!sis1 #cc /ability ( sol> sy/em1 #baj ,latitude1 *anges (1 #acc1 #ach def9ition (1 #acd det]m9+ !1 #f ,lev]ri]1 pr$icts discov]y ( ,neptune1 #fa1 #adb ,lick ,obs]vatory1 ,keel]'s obs]vations1 #adj ,light1 undulatory !ory (1 #ai1 #adh ,light-waves1 measur+ l5g? (1 #bj1 #adi ,logogriph1 by ,huyg5s1 #adc ,long-exposure photography1 #he ,longitude1 c\nt$ ,ea/ & ,we/1 #abe det]m9+1 #f det]m9+ by occultations1 #afg effect on "t diff]5ces1 #abc expla9$1 #abc ( ,wa%+ton1 fir/ det]m9$1 #afh ,macle>1 obs]ves ,eta ,argus1 #bje ,magnitudes1 /ell>1 #ia ,manila1 its "t1 #abg ,maps1 a/ronomical side (1 #aab ,m]idian circle1 expla9$1 #ahi ,milky-way1 poor 9 nebul1 #cc ,m9or ,planets1 see ,a/]oids4 ,,moon1 ,,hoax1 #aii motion among />s1 #afc m\nta9s discov]$ by ,galileo1 #di size (1 measur$1 #aff ,motion ( moon1 #afc ,,motions ( ! ,,e>?',s ,pole1 #aca ,,m\nt+ ,,great ,,telescopes1 #agj ,nak$-eye nebul1 #bh ,naples1 ,royal ,obs]vatory1 latitude obs]vations1 #aci ,naval ,obs]vatory1 ,wa%+ton1 noon signal1 #abj ,,navigation1 #a be=e *ronomet]s1 #c use ( a/ronomy 91 #aac ,,nebul1 #bg ,nebula1 9 ,&rom$a1 #bh 9 ,orion1 #cj keyhole1 #bje ,nebul>1 hypo!sis1 #cc /ructure 9 ,pleiades1 #ag ,nebul\s />s1 #ca ,negative1 & positive1 9 photography1 #hb ,neptune1 discov]y pr$ict$ by ,lev]ri]1 #fa1 #adb discov]y by ,galle1 #fa ,newcomb1 fixes apex ( sol> motion1 #bbb ,newton1 law ( gravitation1 #bab longitude commission1 #h ,new ,york1 its telegraphic "t sy/em1 #abj ,noon ,signal1 ,wa%+ton1 #abj ,numb]1 ( nebul1 #ca1 #cc ( tempor>y />s1 #ch ,nutation1 expla9$1 #ahh ,occultations1 #afa expla9$1 #afe ,occultations1 use (1 #aff1 #afg ,orion nebula1 #cj ,pacific isl&s1 _! longitude & "t1 #abe ,p>allax1 sol>1 #fg1 #ajf /ell>1 #id1 #ajf measur$ ) heliomet]1 #aeh ,p>is1 congress ( a/ronom]s1 #ahhg1 #ajb exposition ( #aijj1 #agf ,p]iodic motion ( e>?'s pole1 #acc ,p]seus1 con/ellation1 tempor>y /> 91 #df ,philipp9e ,isl&s1 _! "t1 #abg ,photography1 a/]oid1 inv5t$ by ,wolf1 #ajd congress ( a/ronomical1 #ajb cumulative effect ( light1 #hd di/ance ( light-s\rce1 #hc d\ble telescopes =1 #hf g5]al />-catalogue1 #ajb ,,9 ,,a/ronomy1 #ha 9 discov]y ( a/]oids1 #fd1 #ajd 9 sol> physics1 #aji 9 spectroscopy1 #ajh l5g? 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