,,! ,,sci5ce ,,( ,,! ,,/>s ,,by ,e4 ,,walt] ,,maund]1 ,f4,r4,a4,s4 ,,( ,,! ,,royal ,,obs]vatory1 ,,gre5wi* ,,au?or ,,( ,,a/ronomy ,,)\t ,a ,,telescope ,,! ,,a/ronomy ,,( ,,! ,,bible1 ,,etc4 ,,london3 ,t4 ,c4 ,e4 ,c4 ,,jack #fg ,,long ,,acre1 ,w4,c41 ,,& ,,ed9burgh ,,new ,,york3 ,,dodge ,,publi%+ ,,co4 vii ,,cont5ts ,,*ap4 ,i4 ,,a/ronomy ,,be=e ,,hi/ory ,,ii4 ,,a/ronomy ,,be=e ,,! ,,telescope ,,iii4 ,,! ,,law ,,( ,,gravitation ,,iv4 ,,a/ronomical ,,measurem5ts ,v4 ,,! ,,memb]s ,,( ,,! ,,sol> ,,sy/em ,,vi4 ,,! ,,sy/em ,,( ,,! ,,/>s ,,index #i ,,! ,,sci5ce ,,( ,,! ,,/>s ,,*apt] ,i ,,a/ronomy ,,be=e ,,hi/ory ,! plan ( ! pres5t s]ies requires ea* volume to be complete 9 ab\t eighty small pages4 ,b no adequate acc\nt ( ! a*ievem5ts ( a/ronomy c possibly be giv5 )9 limits s n>r[1 = s small a space w\ld n suffice = a m]e catalogue ( ! results :i* h be5 obta9$2 & 9 mo/ cases ! result alone w\ld be almo/ mean+less unless "s explanation 7 (f]$ ( ! way 9 :i* x _h be5 rea*$4 ,all1 !re=e1 t c be done 9 a "w ( ! pres5t size is to take ! /ud5t to ! />t+-po9t ( a/ronomy1 %[ him ! v>i\s roads ( rese>* :i* h op5$ out f x1 & give a brief indication ( ! "* & g5]al direction ( ea*4 ,t :i* di/+ui%es a/ronomy f all ! o!r sci5ces is ?is3 x deals ) objects t we _c t\*4 ,! heav5ly bodies are beyond our rea*2 we _c tamp] ) !m1 or subject !m to any =m ( exp]im5t2 we _c br+ !m into our laboratories to analyse or dissect !m4 ,we c only wat* !m & wait = su* indications z _! #aj own movem5ts may supply4 ,b we are conf9$ to ?is e>? ( ours1 & !y are s remote2 we are s %ort-liv$1 & !y are s long-endur+2 t ! difficulty ( f9d+ out mu* ab\t !m might well seem insup]able4 ,yet ^! difficulties h be5 s f> ov]come t a/ronomy is ! mo/ advanc$ ( all ! sci5ces1 ! "o 9 :i* our k is ! mo/ def9ite & c]ta94 ,all sci5ce re/s on sight & ?\ght1 on ord]$ obs]vation & reason$ d$uction2 b bo? sight & ?\ght 7 e>li] tra9$ to ! s]vice ( a/ronomy ?an ( ! o!r physical sci5ces4 ,x is "h t ! highe/ value ( a/ronomy lies2 9 ! discipl9e t x has af=d$ to man's p[]s ( obs]vation & reflection2 & ! real triumphs :i* x has a*iev$ are n ! br++ to light ( ! beauties or ! s5sational dim5sions & di/ances ( ! heav5ly bodies1 b ! vanqui%+ ( difficulties :i* might well h seem$ sup]human4 ,! true _s ( ! sci5ce c be f> bett] exemplifi$ by ! pres5tation ( "s ( ^! difficulties1 & ( ! me?ods by :i* !y h be5 ov]come1 ?an by _m volumes ( picturesque description or ( eloqu5t rhapsody4 ,!re 0 a "t :5 m5 knew no?+ ( a/ronomy2 l e o!r sci5ce x began f z]o4 ,b x is n possible to suppose t su* a /ate ( ?+s la/$ long1 we "k t !re 0 a "t :5 m5 _h notic$ t !re 7 two great lights 9 ! sky--a great] light t %one by day1 a less] light t %one by night--& !re 7 ! />s also4 ,& ?is1 ! e>lie/ obs]vation ( primitive a/ronomy1 is pres]v$ = u1 express$ 9 ! simple/ possible language1 9 ! fir/ *apt] ( ! fir/ book #aa ( ! sacr$ writ+s h&$ d[n to u by ! ,hebrews4 ,?is obs]vation1 t !re are bodies above u giv+ light1 & t !y are n all equally bright1 is s simple1 s inevitable1 t m5 mu/ h made x z soon z !y possess$ any m5tal p[] at all4 ,b1 once made1 a numb] ( que/ions mu/ h intrud$ !mselves3 ,:at are ^! lights8 ,:]e are !y8 ,h[ f> are !y (f8 ,_m diff]5t answ]s 7 e>ly giv5 to ^! que/ions4 ,"s 7 fooli%2 "s1 ?\gh intellig5t1 7 mi/ak52 "s1 ?\gh wrong1 l$ ev5tually to ! discov]y ( ! tru?4 ,_m my?s1 _m leg5ds1 "s full ( beauty & int]e/1 7 inv5t$4 ,b 9 s small a book z ?is x is only possible to glance at ^? l9es ( ?\ght :i* ev5tually l$ to ! true solution4 ,z ! great] light1 ! less] light1 & ! />s 7 c>efully wat*$1 x 0 se5 n only t !y %one1 b t !y appe>$ to move2 sl[ly1 /eadily1 & )\t ceas+4 ,! />s all mov$ toge!r l a column ( soldi]s on ! m>*1 n alt]+ _! positions relative to ea* o!r4 ,! less] light1 ! ,moon1 mov$ ) ! />s1 & yet at ! same "t among !m4 ,! great] light1 ! ,sun1 0 n se5 ) ! />s2 ! brightness ( 8 pres5ce made ! day1 8 abs5ce br\ght ! night1 & x 0 only dur+ 8 abs5ce t ! />s 7 se52 !y fad$ out ( ! sky be=e he came up 9 ! morn+1 & did n reappe> aga9 until aft] he pass$ out ( sight 9 ! ev5+4 ,b !re came a "t :5 x 0 realis$ t !re 7 />s %9+ 9 ! sky all day long z well z at night1 & ?is discov]y 0 "o ( ! greate/ & mo/ important ev] made1 #ab because x 0 ! e>lie/ discov]y ( some?+ q unse54 ,m5 laid hold ( ?is fact1 n f ! direct & imm$iate evid5ce ( _! s5ses1 b f reflection & reason+4 ,we d n "k :o made ?is discov]y1 nor h[ long ago x 0 made1 b f t "t onw>d ! eyes ) :i* m5 look$ ^u nature 7 n only ! eyes ( ! body1 b also ! eyes ( ! m9d4 ,x foll[$ f ?is t ! ,sun1 l ! ,moon1 n only mov$ ) ! g5]al ho/ ( ! />s1 b also among !m4 ,if an obs]v] looks out f any fix$ /ation & wat*es ! ris+ ( "s bright />1 night aft] night1 he w notice t x always appe>s to rise 9 ! same place2 s too ) its sett+4 ,f any giv5 obs]v+ /ation ! direction 9 :i* any p>ticul> /> is obs]v$ to rise or set is inv>iable4 ,n s ) ! ,sun4 ,we are accu/om$ to say t ! ,sun rises 9 ! ea/ & sets 9 ! we/4 ,b ! direction 9 :i* ! ,sun rises 9 midw9t] lies f> to ! s\? ( ! ea/ po9t2 ! direction 9 :i* he rises 9 midsumm] lies z f> to ! nor?4 ,! ,sun is !re=e n only mov+ ) ! />s1 b among !m4 ,?is gradual *ange 9 ! position ( ! ,sun 9 ! sky 0 notic$ 9 _m anci5t nations at an e>ly "t4 ,x is ref]r$ to 9 ,job xxxviii4 #ab3 ,ha/ ?\ comm&$ ! morn+ s9ce ?y days2 & caus$ ! dayspr+ to "k 8 place8 ,& ! app>5t pa? ( ! ,sun on "o day is always p>allel to its pa? on ! days prec$+ & foll[+4 ,:51 !re=e1 ! ,sun rises f> to ! s\? ( ea/1 he sets correspond+ly f> to ! s\? ( we/1 & at noon he is l[ d[n 9 ! s\?4 ,8 c\rse dur+ ! day is a %ort "o1 & ! daylight #ac is mu* %ort] ?an ! night1 & ! ,sun at noon1 be+ l[ d[n 9 ! sky1 has n 8 full p[]4 ,! cold & d>kness ( w9t]1 !re=e1 foll[s directly ^u ?is position ( ! ,sun4 ,^! conditions are rev]s$ :5 ! ,sun rises 9 ! nor?-ea/4 ,! night is %ort1 ! daylight prolong$1 & ! ,sun1 be+ high 9 ! heav5s at noon1 8 heat is felt to ! full4 ,?us ! movem5ts ( ! ,sun are directly connect$ ) ! *anges ( season ^u ! ,e>?4 ,b ! />s also are connect$ ) ^? seasons2 = if we look out imm$iately aft] x has become d>k aft] sunset1 we %all notice t ! />s se5 9 ! night ( w9t] are only 9 "p ^? se5 9 ! nights ( summ]4 ,9 ! nor!rn "p ( ! sky !re are a numb] ( />s :i* are always visible :5ev] we look out1 no matt] at :at "t ( ! night nor :at "p ( ! ye>4 ,if we wat* ?r\gh\t ! :ole night1 we see t ! :ole heav5s appe> to be sl[ly turn+--turn+1 z if all 7 9 a s+le piece--& ! pivot ab\t :i* x is turn+ is high up 9 ! nor!rn sky4 ,! />s1 !re=e1 are divid$ into two classes4 ,^? ne> ?is invisible pivot--! ,pole ( ! ,heav5s1 z we t]m x--move r\nd x 9 complete circles2 !y nev] pass out ( sight1 b ev5 :5 l[e/ !y cle> ! horizon4 ,! o!r />s move r\nd ! same pivot 9 curv$ pa?s1 :i* are evid5tly p>ts ( circles1 b circles ( :i* we d n see ! :ole4 ,^! />s rise on ! ea/]n side ( ! heav5s & set on ! we/]n1 & = a great] or less space ( "t are lo/ to sight bel[ ! horizon4 ,& "s ( ^! />s are visible at "o "t ( ! ye>1 o!rs at ano!r2 "s be+ se5 dur+ ! #ad :ole ( ! long nights ( w9t]1 o!rs ?r\gh\t ! %ort nights ( summ]4 ,?is di/9ction aga91 & its connection ) ! *ange ( ! seasons on ! e>?1 0 obs]v$ _m ages ago4 ,x is allud$ to 9 ,job xxxviii4 #cb3 ,can/ ?\ lead =? ! ,signs ( ! ,zodiac 9 _! season1 or can/ ?\ guide ! ,be> ) h] tra98 7,r4,v41 ,m>g974 ,! ,signs ( ! ,zodiac are tak5 z repres5t+ ! />s :i* rise & set1 & !re=e h ea* _! season = be+ l$ =?1 :ile ! nor!rn />s1 :i* are always visible1 appe>+ to be guid$ 9 _! cont9ual movem5t r\nd ! ,pole ( ! sky 9 p]fect circles1 are repres5t$ by ! ,be> ) h] tra94 ,! *anges 9 position ( ! ,sun1 ! great] light1 mu/ h attract$ att5tion 9 ! v e>lie/ ages1 because ^! *anges are s closely connect$ ) ! *anges ( ! seasons ^u ! ,e>?1 :i* affect m5 directly4 ,! ,moon1 ! less] light1 goes ?r\gh *anges ( position l ! ,sun1 b ^! are n ( ! same direct consequ5ce to m51 & probably mu* less notice 0 tak5 ( !m4 ,b !re 7 *anges ( ! ,moon :i* m5 c\ld n help notic+--h] *anges ( %ape & brightness4 ,"o ev5+ %e may be se5 soon aft] ! ,sun has set1 z a ?9 ar* ( light1 l[ d[n 9 ! sunset sky4 ,on ! foll[+ ev5+s %e is se5 high] & high] 9 ! sky1 & ! b[ ( light increases1 until by ! f\rte5? day x is a p]fect r\nd4 ,!n ! ,moon beg9s to dim9i% & to disappe>1 until1 on ! tw5ty-n9? or ?irtie? day aft] ! fir/ obs]vation1 %e is aga9 se5 9 ! we/ aft] sunset z a n>r[ cresc5t4 ,?is succession ( *anges gave m5 an important measure ( "t1 &1 9 an age :5 artificial means ( light 7 difficult to procure1 moonlight 0 ( ! greate/ #ae value1 & ! return ( ! moonlit portion ( ! mon? 0 eag]ly look$ =4 ,^! e>ly a/ronomical obs]vations 7 simple & obvi\s1 & ( great practical value4 ,! day1 mon?1 & ye> 7 conv5i5t measures ( "t1 & ! p[] ( det]m9+1 f ! obs]vation ( ! ,sun & ( ! />s1 h[ f> ! ye> _h progress$ 0 mo/ important to f>m]s1 z an indication :5 !y %\ld pl\gh & s[ _! l&4 ,su* obs]vations _h probably be5 made indep5d5tly by _m m5 & 9 _m nations1 b 9 "o place a great] advance _h be5 made4 ,! ,sun & ,moon are bo? unmi/akable1 b "o /> is v l ano!r1 &1 = ! mo/ "p1 individual />s c only be recognis$ by _! positions relative to o!rs4 ,! />s 7 !re=e gr\p$ toge!r into ,con/ellations & associat$ ) c]ta9 fanci$ designs1 & twelve ( ^! designs 7 arrang$ 9 a belt r\nd ! sky to m>k ! app>5t pa? ( ! ,sun 9 ! c\rse ( ! ye>1 ^! twelve be+ kn[n z ! ,signs ( ! ,zodiac--! ,ram1 ,bull1 ,tw9s1 ,crab1 ,lion1 ,virg91 ,balance1 ,scorpion1 ,ar*]1 ,goat1 ,wat]-p\r]1 & ,fi%es4 ,9 ! re/ ( ! sky "s ?irty to ?irty-six o!r gr\ps1 or con/ellations1 7 =m$1 ! ,be> be+ ! l>ge/ & brighte/ ( ! con/ellations ( ! nor!rn heav5s4 ,b ^! anci5t con/ellations d n cov] ! entire heav5s2 a l>ge area 9 ! s\? is unt\*$ by !m4 ,& ?is fact af=ds an indication bo? ( ! "t :5 & ! place :]e ! old /ell> gr\ps 7 design$1 = ! region left unt\*$ 0 ! region bel[ ! horizon ( #dj ,nor? latitude1 ab\t #dfjj ye>s ago4 ,x is probable1 !re=e1 t ! anci5t a/ronom]s :o c>ri$ out ?is great "w #af liv$ ab\t #bgjj ,b4,c41 & 9 ,nor? latitude #cg or #ch4 ,! indication is only r\gh1 b ! am\nt ( unc]ta9ty is n v l>ge2 ! con/ellations mu/ be at lea/ #djjj ye>s old1 !y _c be m ?an #ejjj4 ,all ?is 0 done by prehi/oric a/ronom]s2 ?\gh no record ( ! actual c>ry+ out ( ! "w & no names ( ! m5 :o did x h come d[n to u4 ,b x is cle> f ! fact t ! ,signs ( ! ,zodiac are arrang$ s z to m>k out ! annual pa? ( ! ,sun1 & t !y are twelve 9 numb]--!re be+ twelve mon?s 9 ! ye>--t ^? :o design$ ! con/ellations already knew t !re are />s %9+ ne> ! ,sun 9 full daylight1 & t !y _h work$ out "s means = det]m9+ :at />s ! ,sun is ne> at any giv5 "t4 ,ano!r great discov]y ( :i* ! date & ! mak] are equally unkn[n is ref]r$ to 9 only "o ( ! anci5t records available to u4 ,x 0 se5 t all along ! ea/]n horizon1 f nor? to s\?1 />s rise1 & all along ! we/]n horizon1 f nor? to s\?1 />s set4 ,t is :at 0 se52 x 0 ! fact obs]v$4 ,!re is no h9drance any:]e to ! movem5t ( ! />s--!y h a free passage "u ! ,e>?2 ! ,e>? is unsupport$ 9 space4 ,t is :at 0 ?\ght2 x 0 ! inf]5ce drawn4 ,or1 z x is writt5 9 ,job xxvi4 #g1 ,he 7,god7 /ret*e? out ! nor? ov] empty space1 & hange? ! e>? ^u no?+4 ,! ,e>? !re=e floats unsupport$ 9 ! c5tre ( an imm5se />-spangl$ sph]e4 ,& :at is ! %ape ( ! ,e>?8 ,! natural & correct inf]5ce is t x is sph]ical1 & we f9d 9 "s ( ! e>ly ,greek writ]s ! argum5ts :i* e/abli% ?is inf]5ce z cle>ly set =? z !y w\ld be to-day4 #ag ,! same inf]5ce foll[$1 moreov]1 f ! obs]vation ( a simple fact1 namely1 t ! />s z obs]v$ f any p>ticul> place all make ! same angle ) ! horizon z !y rise 9 ! ea/1 & all set at ! same angle ) x 9 ! we/2 b if we g nor?w>d1 we f9d t angle /eadily decreas+2 if we g s\?w>d1 we f9d x increas+4 ,b if ! ,e>? is r\nd l a globe1 !n x mu/ h a def9ite size1 & t size c be measur$4 ,! discov]ies not$ above 7 made by m5 ^: names h be5 lo/1 b ! "n ( ! fir/ p]son :om we "k to h measur$ ! size ( ! ,e>? 0 ,,erato/h5es4 ,he f\nd t ! ,sun 0 directly ov]head at noon at midsumm] at ,sy5e 7! mod]n ,ass\an71 9 ,egypt1 b 0 #g s\? ( ! z5i?--! po9t ov]head--at ,alex&ria1 & f ?is he comput$ ! ,e>? to be #bej1jjj /adia 7a /adium #fjf feet7 9 circumf]5ce4 ,ano!r consequ5ce ( ! c>eful wat* ^u ! />s 0 ! discov]y t five ( !m 7 planets2 w&]+ />s2 !y did n move all 9 "o piece ) ! re/ ( ! cele/ial ho/4 ,9 ?is !y resemble ! ,sun & ,moon1 & !y fur!r resemble ! ,moon 9 t1 ?\gh too small = any *ange ( %ape to be detect$1 !y *ange 9 brightness f "t to "t4 ,b _! movem5ts are m complicat$ ?an ^? ( ! o!r heav5ly bodies4 ,! ,sun moves a little sl[] ?an ! />s1 & s seems to travel among/ !m f we/ to ea/2 ! ,moon moves mu* sl[] ?an ! />s1 s h] motion f we/ to ea/ is m pron\nc$ ?an t ( ! ,sun4 ,b ! five planets sometimes move sl[] ?an ! />s1 sometimes quick]1 & sometimes at ! same rate4 ,two ( ! five1 :i* we n[ "k z ,m]cury #ah & ,v5us1 nev] move f> f ! ,sun1 sometimes be+ se5 9 ! ea/ be=e he rises 9 ! morn+1 & sometimes 9 ! we/ aft] he has set 9 ! ev5+4 ,m]cury is ! clos] to ! ,sun1 & moves m quickly2 ,v5us goes ?r\gh mu* ! great] *anges ( brightness4 ,jupit] & ,saturn move ne>ly at ! same av]age rate z ! />s1 ,saturn tak+ ab\t ?irte5 days m ?an a ye> to come aga9 to ! po9t ( ! sky opposite to ! ,sun1 & ,jupit] ab\t ?irty-f\r days4 ,m>s1 ! fif? planet1 takes two ye>s & fifty days to accompli% ! same j\rney4 ,^! planet>y movem5ts 7 n1 l ^? ( ! ,sun & ,moon & />s1 ( great & obvi\s consequ5ce to m54 ,x 0 important to m5 to "k :5 !y w\ld h moonlight nights1 to "k :5 ! successive seasons ( ! ye> w\ld return4 ,b x 0 no help to m5 to "k :5 ,v5us 0 at h] brighte/ m ?an :5 %e 0 invisible4 ,%e gave !m no useful light1 & %e & h] companion planets return$ at no def9ite seasons4 ,nev]!less1 m5 began to make ord]$ obs]vations ( ! planets--obs]vations t requir$ mu* m pati5ce & p]sev]ance ?an ^? ( ! o!r cele/ial lights4 ,& !y set !mselves ) ! greate/ +5uity to unravel ! secret ( _! complicat$ & seem+ly caprici\s movem5ts4 ,?is 0 a yet high] developm5t ?an any?+ t _h gone be=e1 = m5 7 devot+ "t1 tr\ble1 & pati5t ?\ght1 = long s]ies ( ye>s1 to an inquiry :i* did n promise to br+ !m any pr(it or advantage4 ,yet ! pr(it :i* x actually did br+ 0 ( ! highe/ ord]4 ,x develop$ m5's m5tal p[]s2 x l$ to ! devis+ ( #ai in/rum5ts ( precision = ! obs]vations2 x l$ to ! f\ndation ( ma!matics1 & ?us lay at ! root ( all our mod]n me*anical progress4 ,x br\ght out1 9 a high] degree1 ord]$ obs]vation & ord]$ ?\ght4 #bj ,,*apt] ,,ii ,,a/ronomy ,,be=e ,,! ,,telescope ,!re 0 ?us a real sci5ce ( a/ronomy be=e we h any hi/ory ( x4 ,"s important discov]ies _h be5 made1 & ! fir/ /ep _h be5 tak5 t[>ds catalogu+ ! fix$ />s4 ,x 0 c]ta9ly kn[n to "s ( ! /ud5ts ( ! heav5s1 ?\gh p]haps only to a few1 t ! ,e>? 0 a sph]e1 freely susp5d$ 9 space1 & surr\nd$ on all sides by ! />ry heav5s1 among/ :i* mov$ ! ,sun1 ,moon1 & ! five planets4 ,! g5]al "* ( ! ,sun's movem5t 0 also kn[n2 namely1 t he n only mov$ day by day f ea/ to we/1 z ! />s d1 b also _h a second motion incl9$ at an angle to ! fir/1 & 9 ! opposite direction1 :i* he accompli%$ 9 ! c\rse ( a ye>4 ,to ?is sum ( k1 no d\bt1 sev]al nations _h contribut$4 ,we d n "k to :at race we owe ! con/ellations1 b !re are evid5ces ( an elem5t>y acqua9tance ) a/ronomy on ! "p ( ! ,*9ese1 ! ,babylonians1 ! ,egyptians1 & ! ,jews4 ,b 9 ! second /age ( ! developm5t ( ! sci5ce ! entire cr$it = ! progress made belongs to ! ,greeks4 ,! ,greeks1 z a race1 appe> to h be5 v little apt at orig9at+ ideas1 b !y possess$1 beyond all o!r races1 ! p[] ( develop+ & p]fect+ crude ideas :i* !y _h obta9$ f o!r s\rces1 #ba & :5 once _! att5tion 0 drawn to ! movem5ts ( ! heav5ly bodies1 !y devot$ !mselves ) /rik+ +5uity & success to devis+ !ories to acc\nt = ! appe>ances pres5t$1 to work+ out me?ods ( computation1 &1 la/1 to devis+ in/rum5ts = obs]v+ ! places ( ! lum9>ies 9 :i* !y 7 int]e/$4 ,9 ! brief space available x is only possible to ref] to two or ?ree ( ! m5 ^: comm&+ intellects did s mu* to help on ! developm5t ( ! sci5ce4 ,,eudoxus ( ,knidus1 9 ,asia ,m9or 7#djh-cee ,b4,c471 01 s f> z we "k1 ! fir/ to attempt to repres5t ! movem5ts ( ! heav5ly bodies by a simple ma!matical process4 ,8 root idea 0 some?+ l ?is4 ,! ,e>? 0 9 ! c5tre ( ! univ]se1 & x 0 surr\nd$1 at a great di/ance f u1 by a numb] ( invisible transp>5t %ells1 or sph]es4 ,ea* ( ^! sph]es rotat$ ) p]fect uni=mity1 ?\gh ! spe$ ( rotation diff]$ = diff]5t sph]es4 ,"o sph]e c>ri$ ! />s1 & rotat$ f ea/ to we/ 9 ab\t #bc h4 #ef m4 ,! ,sun 0 c>ri$ by ano!r sph]e1 :i* rotat$ f we/ to ea/ 9 a ye>1 b ! pivots1 or poles1 ( ?is sph]e 7 c>ri$ by a second1 rotat+ exactly l ! sph]e ( ! />s4 ,?is expla9$ h[ x is t ! ecliptic--t is to say1 ! app>5t pa? ( ! ,sun among/ ! />s--is incl9$ #bc- to ! equator ( ! sky1 s t ! ,sun is #bc- nor? ( ! equator at midsumm] & #bc- s\? ( ! equator at midw9t]1 = ! poles ( ! sph]e peculi> to ! ,sun 7 suppos$ to be #bc- f ! poles ( ! sph]e peculi> to ! />s4 ,!n ! ,moon _h ?ree sph]es2 t :i* actually c>ri$ ! ,moon hav+ its poles #e f ! poles ( ! sph]e peculi> to ! #bb ,sun4 ,^! poles 7 c>ri$ by a sph]e plac$ l ! sph]e ( ! ,sun1 b rotat+ 9 #bg days2 & ?is1 aga91 _h its poles 9 ! sph]e ( ! />s4 ,! sph]e c>ry+ ! ,moon af=d$ ! explanation ( ! wavy motion ( ! ,moon to & fro across ! ecliptic 9 ! c\rse ( a mon?1 = at "o "t 9 ! mon? ! ,moon is #e nor? ( ! ecliptic1 at ano!r "t #e s\?4 ,! motions ( ! planets 7 m difficult to repres5t1 because !y n only h a g5]al daily motion f ea/ to we/1 l ! />s1 & a g5]al motion f we/ to ea/ along ! ecliptic1 l ! ,sun & ,moon1 b f "t to "t !y turn back on _! c\rse 9 ! ecliptic1 & retrograde4 ,b ! introduction ( a ?ird & f\r? sph]e enabl$ ! motions ( mo/ ( ! planets to be fairly repres5t$4 ,!re 7 ?us tw5ty-sev5 sph]es 9 all--f\r = ea* ( ! five planets1 ?ree = ! ,moon1 ?ree = ! ,sun 7includ+ "o n m5tion$ 9 ! =ego+ summ>y71 & "o = ! />s4 ,^! sph]es 7 n1 h[ev]1 suppos$ to be solid /ructures really exi/+2 ! !ory 0 simply a means = repres5t+ ! obs]v$ motions ( ! heav5ly bodies by computations bas$ ^u a s]ies ( uni=m movem5ts 9 conc5tric circles4 ,b ?is assumption t ea* heav5ly body moves 9 its pa? at a uni=m rate 0 soon se5 to be contr>y to fact4 ,a ref]5ce to ! almanac w %[ at once t ! ,sun's movem5t is n uni=m4 ,?us = ! ye> #aiaj-aa ! sol/ices & equ9oxes fell z giv5 on ! next page3 #bc ,epo* ,"t ,int]val ,w9t] ,sol/ice #aiaj ,dec4 #bb d4 #e h4 #ab m4 ,p4,m4 #hi d4 #j h4 #db m4 ,spr+ ,equ9ox #aiaa ,m>4 #ba #e #ed ,p4,m4 #ib #ai #da ,summ] ,sol/ice #aial ,june #bb #a #ce ,p4,m4 #ic #ad #dc ,autumn ,equ9ox #aiaa ,sept4 #bd #d #ah ,a4,m4 #hi #ah #cf ,w9t] ,sol/ice #aiaa ,dec4 #bb #aj #ed ,p4,m4 s t ! w9t] half ( ! ye> is %ort] ?an ! summ] half2 ! ,sun moves m quickly ov] ! half ( its orbit :i* is s\? ( ! equator ?an ov] ! half :i* is nor? ( x4 ,! motion ( ! ,moon is m irregul> /ill1 z we c see by tak+ out f ! almanac ! times ( new & full moon3 ,new ,moon ,int]val to ,full ,moon ,dec4 #aiaj #a d4 #i h4 #aj4g m4 ,p4,m4 #ad d4 #ac h4 #ed4d m4 #ca #d #ba4b ,p4,m4 #ad #f #d4h ,jan4 #aiaa #cj #i #dd4g ,a4,m4 #ad #j #eb4h ,m>* #a #j #ca4a ,a4,m4 #ac #bc #bg4d #cj #j #cg4h ,p4,m4 #ad #a #eh4h ,april #bh #aj #be4j ,p4,m4 #ad #g #dd4g ,may #bh #f #bd4d ,a4,m4 #ad #ae #bf4c ,june #bf #a #ai4g ,p4,m4 #ad #bc #cc4g ,july #be #h #ab4j ,p4,m4 #ae #f #db4g ,aug4 #bd #d #ad4c ,a4,m4 #ae #aa #db4d ,sept4 #bb #b #cg4d ,p4,m4 #ae #ac #cc4g ,oct4 #bb #d #i4c ,a4,m4 #ae #aa #ch4h ,nov4 #bj #h #di4d ,p4,m4 #ae #f #b4e ,dec4 #bj #c #dj4c ,p4,m4 #ad #ba #di4d #bd ,full ,moon ,int]val to ,new ,moon ,dec4 #aiaj #af d #aa h4 #e4a m4 ,a4,m4 #ae d4 #e h4 #af4a m4 ,jan4 #aiaa #ad #aj #bf4j ,p4,m4 #ae #aa #ah4g ,feb4 #ac #aj #cg4e ,a4,m4 #ae #ac #ec4f ,m>* #ad #aa #eh4e ,p4,m4 #ae #ab #ci4c ,april #ac #b #cf4f ,p4,m4 #ae #g #dh4d ,may #ac #f #i4g ,a4,m4 #ae #j #ad4g ,june #aa #i #ej4g ,p4,m4 #ad #ae #bi4j ,july #aa #j #ec4d ,p4,m4 #ad #g #ah4f ,aug4 #aj #b #ed4g ,a4,m4 #ad #a #ai4f ,sept4 #h #c #ef4g ,p4,m4 #ac #bb #dj4g ,oct4 #h #d #aa4a ,a4,m4 #ac #bc #eh4b ,nov4 #f #c #dh4a ,p4,m4 #ad #e #a4c ,dec4 #f #b #ea4i ,a4,m4 #ad #ab #dh4d ,jan4 #aiab #d #a #ii4g ,p4,m4 #ad #ba #dj4c ,! a/ronom] :o dealt ) ?is difficulty 0 ,,hipp>*us 7ab\t #aij-abj ,b4,c471 :o 0 born at ,nica1 9 ,bi?ynia1 b made mo/ ( 8 a/ronomical obs]vations 9 ,rhodes4 ,he attempt$ to expla9 ^! irregul>ities 9 ! motions ( ! ,sun & ,moon by suppos+ t ?\gh !y really mov$ uni=mly 9 _! orbits1 yet ! c5tre ( _! orbits 0 n ! c5tre ( ! ,e>?1 b 0 situat$ a little di/ance f x4 ,?is po9t 0 call$ ! exc5tric1 & ! l9e f ! exc5tric to ! ,e>? 0 call$ ! l9e ( apsides4 ,b :5 he tri$ to deal ) ! movem5ts ( ! planets1 he f\nd t !re 7 n en\gh good obs]vations available = him to build up any satisfactory !ory4 ,he !re=e devot$ himself to ! "w ( mak+ sy/ematic det]m9ations ( ! places ( ! planets t he might put 8 successors 9 a bett] position to deal ) ! problem ?an he 04 ,8 great successor 0 ,,claudius ,,ptolemy ( #be ,alex&ria1 :o c>ri$ ! "w ( a/ronomical obs]vation f ab\t ,a4,d4 #abg to #aej4 ,he 01 h[ev]1 mu* great] z a ma!matician ?an z an obs]v]1 & he work$ out a v elaborate s*eme1 by :i* he 0 able to repres5t ! motions ( ! planets ) consid]able accuracy4 ,! sy/em 0 an extremely complex "o1 b its pr9ciple may be repres5t$ z foll[s3 ,if we suppose t a planet is mov+ r\nd ! ,e>? 9 a circle at a uni=m rate1 & we tri$ to compute ! place ( ! planet on ?is assumption = regul> int]vals ( "t1 we %\ld f9d t ! planet gradually got fur!r & fur!r away f ! pr$ict$ place4 ,!n aft] a c]ta9 "t ! error w\ld rea* a maximum1 & beg9 to dim9i%1 until ! error vani%$ & ! planet 0 9 ! pr$ict$ place at ! prop] "t4 ,! error w\ld !n beg9 to fall 9 ! opposite direction1 & w\ld increase z be=e to a maximum1 subsequ5tly dim9i%+ aga9 to z]o4 ,?is /ate ( ?+s might be met by suppos+ t ! planet 0 n itself c>ri$ by ! circle r\nd ! e>?1 b by an epicycle--i4e4 a circle travell+ ^u ! fir/ circle--& by judici\sly *oos+ ! size ( ! epicycle & ! "t ( revolution ! bulk ( ! errors 9 ! planet's place might be repres5t$4 ,b /ill !re w\ld be small] errors go+ ?r\gh _! own p]iod1 & ^!1 aga91 w\ld h to be met by imag9+ t ! fir/ epicycle c>ri$ a second1 & x might be t ! second c>ri$ a ?ird1 & s on4 ,! ,ptolemaic sy/em 0 m complicat$ ?an ?is brief summ>y w\ld sugge/1 b x is n possible "h to d m ?an indicate ! g5]al pr9ciples ^u :i* x 0 f\nd$1 & ! num]\s o!r sy/ems or modifications ( !m produc$ 9 ! #bf five c5turies f ,eudoxus to ,ptolemy mu/ be left unnotic$4 ,! po9t to be borne 9 m9d is t "o fundam5tal assumption und]lay !m all1 an assumption fundam5tal to all sci5ce--! assumption t l causes mu/ always produce l effects4 ,x 0 app>5t to ! anci5t a/ronom]s t ! />s--t is to say1 ! great majority ( ! heav5ly bodies--d move r\nd ! ,e>? 9 circles1 & ) a p]fect uni=mity ( motion1 & x seem$ inevitable t1 if "o body mov$ r\nd ano!r1 x %\ld ?us move4 ,= if ! revolv+ body came ne>] to ! c5tre at "o "t & rec$$ at ano!r1 if x mov$ fa/] at "o "t & sl[] at ano!r1 !n1 ! cause rema9+ ! same1 ! effect seem$ to be diff]5t4 ,any complexity introduc$ by sup]pos+ "o epicycle ^u ano!r seem$ pref]able to ab&on+ ?is great fundam5tal pr9ciple ( ! p]fect uni=mity ( ! act+s ( ,nature4 ,= m ?an #acjj ye>s ! ,ptolemaic sy/em rema9$ )\t s]i\s *all5ge1 & ! next great "n t x is necess>y to notice is t ( ,,cop]nicus 7#adgc-aedc74 ,cop]nicus 0 a canon ( ,frau5burg1 & l$ ! quiet1 retir$ life ( a /ud5t4 ,! great "w :i* made him immortal1 ,de ,revolutionibus1 0 ! result ( _m ye>s' m$itation & "w1 & 0 n pr9t$ until he 0 on 8 dea?b$4 ,9 ?is "w ,cop]nicus %[$ t he 0 "o ( ^? great ?9k]s :o are able to look beyond ! m]e appe>ance ( ?+s & to grasp ! reality ( ! unse54 ,cop]nicus realis$ t ! appe>ance w\ld be j ! same :e!r ! :ole />ry vault rotat$ e tw5ty-f\r h\rs r\nd an immovable ,e>? f ea/ to we/ or ! ,e>? rotat$ f we/ to ea/ 9 ! mid/ ( ! />ry sph]e2 &1 z ! #bg />s are at an immeasurable di/ance1 ! latt] conception 0 mu* ! simpl]4 ,ext5d+ ! idea ( ! ,e>?'s motion fur!r1 ! supposition t1 in/ead ( ! ,sun revolv+ r\nd a fix$ ,e>? 9 a ye>1 ! ,e>? revolv$ r\nd a fix$ ,sun1 made at once an imm5se simplification 9 ! planet>y motions4 ,! reason became obvi\s :y ,m]cury & ,v5us 7 se5 fir/ on "o side ( ! ,sun & !n on ! o!r1 & :y nei!r ( !m c\ld move v f> f ! ,sun2 _! orbits 7 )9 ! orbit ( ! ,e>?4 ,! /ation>y po9ts & retrogressions ( ! planets 7 also expla9$2 =1 z ! ,e>? 0 a planet1 & z ! planets mov$ 9 orbits ( diff]5t sizes1 ! out] planets tak+ a long] "t to complete a revolution ?an ! inn]1 x foll[$1 ( necessity1 t ! ,e>? 9 h] motion w\ld f "t to "t be pass$ by ! two inn] planets1 & w\ld ov]take ! ?ree out]4 ,! *ief ( ! ,ptolemaic epicycles 7 done away )1 & all ! planets mov$ cont9u\sly 9 ! same direction r\nd ! ,sun4 ,b no planet's motion c\ld be repres5t$ by uni=m motion 9 a s+le circle1 & ,cop]nicus _h /ill to make use ( sy/ems ( epicycles to acc\nt = ! deviations f regul>ity 9 ! planet>y motions r\nd ! ,sun4 ,! ,e>? hav+ be5 ab&on$ z ! c5tre ( ! univ]se1 a fur!r sacrifice _h to be made3 ! pr9ciple ( uni=m motion 9 a circle1 :i* _h seem$ s necess>y & inevitable1 _h also to be giv5 up4 ,= ! "t came :5 ! in/rum5ts = measur+ ! positions ( ! />s & planets _h be5 mu* improv$1 l>gely due to ,,ty*o ,,brahe 7#aedf-afja71 a ,dane ( noble bir?1 :o 0 ! ke5e/ & mo/ c>eful obs]v] t a/ronomy _h yet produc$4 #bh ,8 obs]vations enabl$ 8 fri5d & pupil1 ,,johann ,,kepl]1 7#aega-afcj71 to subject ! planet>y movem5ts to a f> m se>*+ exam9ation ?an _h yet be5 attempt$1 & he discov]$ t ! ,sun is 9 ! plane ( ! orbit ( ea* ( ! planets1 & also 9 its l9e ( apsides--t is to say1 ! l9e jo9+ ! two po9ts ( ! orbit :i* are respectively ne>e/ & fur!/ f ! ,sun4 ,cop]nicus _h n be5 aw>e ( ei!r ( ^! two relations1 b _! discov]y greatly /r5g!n$ ! ,cop]nican !ory4 ,!n = _m ye>s ,kepl] tri$ "o exp$i5t aft] ano!r 9 ord] to f9d a comb9ation ( circul> motions :i* w\ld satisfy ! problem be=e him1 until at l5g? he 0 l$ to disc>d ! circle & try a diff]5t curve--! oval or ellipse4 ,n[ ! prop]ty ( a circle is t e po9t ( x is situat$ at ! same di/ance f ! c5tre1 b 9 an ellipse !re are two po9ts )9 x1 ! foci1 & ! sum ( ! di/ances ( any po9t on ! circumf]5ce f ^! two foci is con/ant4 ,if ! two foci are at a great di/ance f ea* o!r1 !n ! ellipse is v long & n>r[2 if ! foci are close toge!r1 ! ellipse diff]s v little f a circle2 & if we imag9e t ! two foci actually co9cide1 ! ellipse becomes a circle4 ,:5 ,kepl] tri$ motion 9 an ellipse in/ead ( motion 9 a circle1 he f\nd t x repres5t$ correctly ! motions ( all ! planets )\t any ne$ = epicycles1 & t 9 ea* case ! ,sun occupi$ "o ( ! foci4 ,& ?\gh ! planet did n move at a uni=m spe$ 9 ! ellipse1 yet its motion 0 gov]n$ by a uni=m law1 = ! /raight l9e jo9+ ! planet to ! ,sun1 ! radius vector1 pass$ ov] equal areas ( space 9 equal p]iods ( "t4 #bi ,^! two discov]ies are kn[n z ,kepl]'s ,fir/ & ,second ,laws4 ,8 ,?ird ,law connects all ! planets toge!r4 ,x 0 kn[n t ! out] planets n only take long] to revolve r\nd ! ,sun ?an ! inn]1 b t _! actual motion 9 space is sl[]1 & ,kepl] f\nd t ?is actual spe$ ( motion is inv]sely z ! squ>e root ( its di/ance f ! ,sun2 or1 if ! squ>e ( ! spe$ ( a planet be multipli$ by its di/ance f ! ,sun1 we get ! same result 9 ea* case4 ,?is is usually express$ by say+ t ! cube ( ! di/ance is proportional to ! squ>e ( ! "t ( revolution4 ,?us ! v>y+ rate ( motion ( ea* planet 9 its orbit is n only subject to a s+le law1 b ! v diff]5t spe$s ( ! diff]5t planets are also all subject to a law t is ! same = all4 ,?us ! :ole ( ! complicat$ ma*9]y ( ,ptolemy _h be5 r$uc$ to ?ree simple laws1 :i* at ! same "t repres5t$ ! facts ( obs]vation mu* bett] ?an any possible developm5t ( ! ,ptolemaic me*anism4 ,on 8 discov]y ( 8 ?ird law ,kepl] _h writt53 ,! book is writt5 to be read ei!r n[ or by po/]ity--,i c>e n :i*2 x may well wait a c5tury = a read]1 z ,god has wait$ #fjjj ye>s = an obs]v]4 ,twelve ye>s aft] 8 dea?1 on ,*ri/mas ,day #afdb 7old /yle71 ne> ,gran?am1 9 ,l9coln%ire1 ! pr$e/9$ read] 0 born4 ,! inn] mean+ ( ,kepl]'s ?ree laws 0 br\ght to light by ,,isaac ,,newton4 #cj ,,*apt] ,,iii ,,! ,,law ,,( ,,gravitation ,! fundam5tal ?\ght :i*1 recognis$ or n1 _h la9 at ! root ( ! ,ptolemaic sy/em1 z inde$ x lies at ! root ( all sci5ce1 0 t l causes mu/ always produce l effects4 ,^u ?is pr9ciple !re seem$ to ! anci5t a/ronom]s no escape f ! inf]5ce t ea* planet mu/ move at a uni=m spe$ 9 a circle r\nd its c5tre ( motion4 ,=1 if !re be any =ce t5d+ to alt] ! di/ance ( ! planet f t c5tre1 x seem$ inevitable t soon] or lat] x %\ld ei!r rea* t c5tre or be indef9itely remov$ f x4 ,if !re be no su* =ce1 !n ! planet's di/ance f t c5tre mu/ rema9 inv>iable1 & if x move at all1 x mu/ move 9 a circle2 move uni=mly1 because !re is no =ce ei!r to ha/5 or ret>d x4 ,uni=m motion 9 a circle seem$ a necessity ( nature4 ,b all ?is sy/em1 logical & inevitable z x _h once seem$1 _h gone d[n be=e ! assault ( obs]v$ facts4 ,! great example ( uni=m circul> motion _h be5 ! daily revolution ( ! /> sph]e2 b ?is 0 n[ se5 to be only app>5t1 ! result ( ! rotation ( ! ,e>?4 ,! planets revolv$ r\nd ! ,sun1 b ! ,sun 0 n 9 ! c5tre ( _! motion2 !y mov$1 n 9 circles1 b 9 ellipses2 n at a uni=m spe$1 b at a spe$ :i* dim9i%$ ) ! increase ( _! di/ance f #ca ! ,sun4 ,!re 0 ne$1 !re=e1 = an entire revision ( ! pr9ciples ^u :i* motion 0 suppos$ to take place4 ,! mi/ake ( ! anci5ts _h be5 t !y suppos$ t cont9u$ motion dem&$ fre% applications ( =ce4 ,!y notic$ t a ball1 set roll+1 soon] or lat] came to a /op2 t a p5dulum1 set sw++1 might sw+ = a good "t1 b ev5tually came to re/2 &1 z ! =ces t 7 *eck+ ! motion--t is to say1 ! friction ex]cis$ by ! gr\nd1 ! atmosph]e1 & ! l--did n obtrude !mselves1 !y 7 ov]look$4 ,newton br\ght out into cle> /atem5t ! true conditions ( motion4 ,a body once mov+1 if act$ ^u by no =ce :atsoev]1 mu/ cont9ue to move =w>d 9 a /raight l9e at exactly ! same spe$1 & t = ev]4 ,x does n require any ma9ta9+ =ce to keep x go+4 ,if any *ange 9 its spe$ or 9 its direction takes place1 t *ange mu/ be due to ! introduction ( "s fur!r =ce4 ,?is pr9ciple1 t1 if no =ce acts on a body 9 motion1 x w cont9ue to move uni=mly 9 a /raight l9e1 is ,newton's ,fir/ ,law ( ,motion4 ,8 ,second lays x d[n t1 if =ce acts on a body1 x produces a *ange ( motion proportionate to ! =ce appli$1 & 9 ! same direction4 ,& ! ,?ird ,law /ates t :5 "o body ex]ts =ce ^u ano!r1 t second body reacts ) equal =ce ^u ! fir/4 ,! problem ( ! motions ( ! planets 01 !re=e1 n :at kept !m mov+1 b :at made !m deviate f motion 9 a /raight l9e1 & deviate by diff]5t am\nts4 ,x 0 q cle>1 f ! "w ( ,kepl]1 t ! =ce deflect+ ! planets f uni=m motion 9 a #cb /raight l9e lay 9 ! ,sun4 ,! facts t ! ,sun lay 9 ! plane ( ! orbits ( all ! planets1 t ! ,sun 0 9 "o ( ! foci ( ea* ( ! planet>y ellipses1 t ! /raight l9e jo9+ ! ,sun & planet mov$ = ea* planet ov] equal areas 9 equal p]iods ( "t1 e/abli%$ ?is fact cle>ly4 ,b ! am\nt ( deflection 0 v diff]5t = diff]5t planets4 ,?us ! orbit ( ,m]cury is mu* small] ?an t ( ! ,e>?1 & is travell$ ov] 9 a mu* %ort] "t1 s t ! di/ance by :i* ,m]cury is deflect$ 9 a c\rse ( an h\r f movem5t 9 a /raight l9e is mu* great] ?an t by :i* ! ,e>? is deflect$ 9 ! same "t1 ,m]cury fall+ t[>ds ! ,sun by ab\t #aei miles1 :il/ ! fall ( ! ,e>? is only ab\t #bc4i miles4 ,! =ce draw+ ,m]cury t[>ds ! ,sun is !re=e #f4ff times t draw+ ! ,e>?1 b #f4ff is ! squ>e ( #b4eh1 & ! ,e>? is #b4eh times z f> f ! ,sun z ,m]cury4 ,simil>ly1 ! fall 9 an h\r ( ,jupit] t[>ds ! ,sun is ab\t #j4hh miles1 s t ! =ce draw+ ! ,e>? is #bg times t draw+ ,jupit] t[>ds ! ,sun4 ,b #bg is ! squ>e ( #e4b1 & ,jupit] is #e4b times z f> f ! ,sun z ! ,e>?4 ,simil>ly ) ! o!r planets4 ,! =ce1 !re=e1 :i* deflects ! planets f motion 9 a /raight l9e1 & compels !m to move r\nd ! ,sun1 is "o :i* v>ies inv]sely z ! squ>e ( ! di/ance4 ,b ! ,sun is n ! only attract+ body ( :i* we "k4 ,! old ,ptolemaic sy/em 0 correct to a small ext5t2 ! ,e>? is ! c5tre ( motion = ! ,moon1 :i* revolves r\nd x at a mean di/ance ( #bch1hjj miles1 & 9 a p]iod ( #bg d4 #g h4 #dc m4 ,h5ce ! circumf]5ce ( h] orbit is #a1ejj1dej miles1 & ! l5g? ( ! /raight l9e :i* %e w\ld travel #cc 9 "o second ( "t1 if n deflect$ by ! ,e>?1 is #bhbh feet4 ,9 ?is di/ance ! deviation ( a circle f a /raight l9e is "o in* divid$ by #ah4ff4 ,b we "k f exp]im5t t a /one let fall f a height ( #aic in*es above ! ,e>?'s surface w rea* ! gr\nd 9 exactly "o second ( "t4 ,! =ce draw+ ! /one to ! ,e>?1 !re=e1 is #aic x #ah4ff2 i4e4 #cfja times z great z t draw+ ! ,moon4 ,b ! /one is only #a_/ccj ( a mile f ! ,e>?'s surface1 :ile ! ,moon is #bch1hjj miles away--m ?an #gh million times z f>4 ,! =ce1 !re=e1 w\ld seem n to be dim9i%$ 9 ! proportion t ! di/ance is increas$--mu* less 9 ! proportion ( its squ>e4 ,b ,newton prov$ t a sph]e ( uni=m d5sity1 or made up ( any numb] ( conc5tric %ells ( uni=m d5sity1 attract$ a body outside itself1 j z if its entire mass 0 conc5trat$ at its c5tre4 ,! di/ance ( ! /one f ! ,e>? mu/ !re=e be measur$1 n f ! ,e>?'s surface1 b f its c5tre2 9 o!r words1 we mu/ consid] ! /one z be+ di/ant f ! ,e>?1 n "s #af feet1 b #cifc miles4 ,?is is v ne>ly "o-sixtie? ( ! ,moon's di/ance1 & ! squ>e ( #fj is #cfjj4 ,! ,e>?'s pull ^u ! ,moon1 !re=e1 is almo/ exactly 9 ! inv]se squ>e ( ! di/ance z comp>$ ) its pull on ! /one4 ,kepl]'s book _h f\nd its read]4 ,8 ?ree laws 7 b ?ree p>ticul> aspects ( ,newton's great discov]y t ! planets mov$ "u ! influ5ce ( a =ce1 lodg$ 9 ! ,sun1 :i* v>i$ inv]sely z ! squ>e ( _! di/ances f x4 ,b ,newton's "w w5t f> beyond ?is1 = he %[$ t ! same law gov]n$ ! motion ( ! ,moon r\nd ! #cd ,e>? & ! motions ( ! satellites revolv+ r\nd ! diff]5t planets1 & also gov]n$ ! fall ( bodies ^u ! ,e>? itself4 ,x 0 univ]sal ?r\gh\t ! sol> sy/em4 ,! law1 !re=e1 is /at$ z ( univ]sal application4 ,e p>ticle ( matt] 9 ! univ]se attracts e o!r p>ticle ) a =ce v>y+ inv]sely z ! squ>e ( ! di/ance betwe5 !m1 & directly z ! product ( ! masses ( ! two p>ticles4 ,& ,newton fur!r prov$ t if a body1 project$ 9 free space & mov+ ) any velocity1 became subject to a c5tral =ce act+1 l gravitation1 inv]sely z ! squ>e ( ! di/ance1 x mu/ revolve 9 an ellipse1 or 9 a closely alli$ curve4 ,^! curves are :at are kn[n z ! conic sections--t is1 !y are ! curves f\nd :5 a cone is cut across 9 diff]5t directions4 ,_! relation to ea* o!r may be illu/rat$ ?us4 ,if we h a v p[]ful light em]g+ f a m9ute hole1 !n1 if we place a scre5 9 ! pa? ( ! beam ( light1 & exactly at "r angles to its axis1 ! light fall+ on ! scre5 w fill an exact circle4 ,if we turn ! scre5 s z to be incl9$ to ! axis ( ! beam1 ! circle w l5g!n out 9 "o direction1 & w become an ellipse4 ,if we turn ! scre5 /ill fur!r1 ! ellipse w l5g!n & l5g!n1 until at la/1 :5 ! scre5 has become p>allel to "o ( ! edges ( ! beam ( light1 ! ellipse w only h "o end2 ! o!r w be lo/4 ,= x is cle> t t edge ( ! beam ( light :i* is p>allel to ! scre5 c nev] meet x4 ,! curve n[ %[n on ! scre5 is call$ a p>abola1 & if ! scre5 is turn$ fur!r yet1 ! b\nd>ies ( ! light fall+ ^u x become div]g5t1 & we h a f\r? curve1 ! hyp]bola4 ,bodies mov+ "u ! influ5ce ( #ce gravitation c move 9 any ( ^! curves1 b only ! circle & ellipse are clos$ orbits4 ,a p>ticle mov+ 9 a p>abola or hyp]bola c only make "o approa* to its attract+ body2 aft] su* approa* x cont9ually rec$es f x4 ,z ! circle & p>abola are only ! two extreme =ms ( an ellipse1 ! two foci be+ at ! same po9t = ! circle & at an inf9ite di/ance ap>t = ! p>abola1 we may reg>d all orbits "u gravitation z be+ ellipses ( "o =m or ano!r4 ,f 8 great demon/ration ( ! law ( gravitation1 ,newton w5t on to apply x 9 _m directions4 ,he %[$ t ! ,e>? c\ld n be truly sph]ical 9 %ape1 b t !re mu/ be a flatt5+ ( its poles4 ,he %[$ also t ! ,moon1 :i* is expos$ to ! attractions bo? ( ! ,e>? & ( ! ,sun1 &1 to a s5sible ext5t1 ( "s ( ! o!r planets1 mu/ %[ irregul>ities 9 h] motion1 :i* at t "t _h n be5 notic$4 ,! ,moon's orbit is incl9$ to t ( ! ,e>?1 cutt+ its plane 9 two opposite po9ts1 call$ ! nodes4 ,x _h long be5 obs]v$ t ! position ( ! nodes travell$ r\nd ! ecliptic once 9 ab\t n9ete5 ye>s4 ,newton 0 able to %[ t ?is 0 a consequ5ce ( ! ,sun's attraction ^u ! ,moon4 ,& he fur!r made a p>ticul> application ( ! pr9ciple ?us br\ght out1 =1 ! ,e>? n be+ a true sph]e1 b flatt5$ at ! poles & bulg+ at ! equator1 ! equatorial belt might be reg>d$ z a compact r+ ( satellites revolv+ r\nd ! ,e>?'s equator4 ,?is1 !re=e1 w\ld t5d to retrograde precisely z ! nodes ( a s+le satellite w\ld1 s t ! axis ( ! equatorial belt ( ! ,e>?--9 o!r words1 ! axis ( ! ,e>?--mu/ revolve r\nd ! pole ( ! ecliptic4 #cf ,consequ5tly ! pole ( ! heav5s appe>s to move among/ ! />s1 & ! po9t :]e ! cele/ial equator crosses ! equator necess>ily moves ) x4 ,?is is :at we "k z ! ,precession ( ! ,equ9oxes1 & x is f our k ( ! fact & ! am\nt ( precession t we are able to det]m9e r\ghly ! date :5 ! fir/ great "w ( a/ronomical obs]vation 0 accompli%$1 namely1 ! gr\p+ ( ! />s into con/ellations by ! a/ronom]s ( ! prehi/oric age4 ,! publication ( ,newton's great "w1 ! ,pr9cipia 7,! ,ma!matical ,pr9ciples ( ,natural ,philosophy71 9 :i* he develop$ ! ,laws ( ,motion1 ! significance ( ,kepl]'s ,?ree ,planet>y ,laws1 & ! ,law ( ,univ]sal ,gravitation1 took place 9 #afhg1 & 0 due to 8 fri5d ,,edmund ,,halley1 to :om he _h confid$ _m ( 8 results4 ,t he 0 ! means ( secur+ ! publication ( ! ,pr9cipia is ,halley's highe/ claim to ! gratitude ( po/]ity1 b 8 own "w 9 ! field :i* ,newton _h op5$ 0 ( great importance4 ,newton _h treat$ comets z mov+ 9 p>abolic orbits1 & ,halley1 collect+ all ! obs]vations ( comets t 7 available to him1 work$ out ! p>ticul>s ( _! orbits on ?is assumption1 & f\nd t ! elem5ts ( ?ree 7 v closely simil>1 & t ! int]val betwe5 _! appe>ances 0 ne>ly ! same1 ! comets hav+ be5 se5 9 #aeca1 #afjg1 & #afhb4 ,on fur!r consult+ old records he f\nd t comets _h be5 obs]v$ 9 #adef1 #acgh1 & #acja4 ,he conclud$ t ^! 7 diff]5t appe>ances ( ! same object1 & pr$ict$ t x w\ld be se5 aga9 9 #ageh1 or1 accord+ to a lat] & m c>eful computation1 9 #agei4 ,z ! "t = its return drew ne>1 ,,clairaut #cg comput$ ) ! utmo/ c>e ! ret>dation :i* w\ld be caus$ to ! comet by ! attractions ( ,jupit] & ,saturn4 ,! comet made its pr$ict$ ne>e/ approa* to ! ,sun on ,m>* #ac1 #agei1 j "o mon? e>li] ?an ,clairaut _h comput$4 ,b 9 its next return1 9 #ahce1 ! computations effect$ by ,,pont,,c\lant 7 only two days 9 error1 s c>efully _h ! comet be5 foll[$ dur+ its unse5 j\rney to ! conf9es ( ! sol> sy/em & back aga91 dur+ a p]iod ( sev5ty-five ye>s4 ,pontc\lant's exploit 0 outdone at ! next return by ,drs4 ,,c[ell & ,,crommel91 ( ,gre5wi* ,obs]vatory1 :o n only comput$ ! "t ( its p]ihelion passage--t is to say1 its ne>e/ approa* to ! ,sun--= ,april #af1 #aiaj1 b foll[$ ! comet back 9 its w&]+s dur+ all its returns to ! ye> #bdj ,b4,c4 ,halley's ,comet1 !re=e1 0 ! fir/ comet t 0 kn[n to travel 9 a clos$ orbit & to return to ! neighb\rhood ( ! ,sun4 ,n a few small or telescopic comets are n[ kn[n to be p]iodic1 b ,halley's is ! only "o :i* has made a figure to ! nak$ eye4 ,notices ( x occur n a few times 9 hi/ory2 x 0 ! comet l a flam+ sword :i* ,josephus describ$ z hav+ be5 se5 ov] ,j]usalem n v long be=e ! de/ruction by ,titus4 ,x 0 also ! comet se5 9 ! spr+ ( ! ye> :5 ,william ! ,conqu]or invad$ ,engl&1 & 0 skilfully us$ by t lead] z an om5 ( 8 com+ victory4 ,! law ( gravitation _h !re=e enabl$ m5 to recognise 9 ,halley's ,comet an addition to ! numb] ( ! prim>y bodies 9 ! sol> sy/em--! fir/ addition t _h be5 made s9ce prehi/oric times4 ,on ,m>* #ac1 #agha1 ,sir ,,william ,,h]s*el #ch detect$ a new object1 :i* he at fir/ suppos$ to be a comet1 b aft]w>ds recognis$ z a planet f> beyond ! orbit ( ,saturn4 ,?is planet1 to :i* ! "n ( ,uranus 0 f9ally giv51 _h a mean di/ance f ! ,sun n9ete5 times t ( ! ,e>?1 & a diamet] f\r times z great4 ,?is 0 a second addition to ! sol> sy/em1 b x 0 a discov]y by sight1 n by d$uction4 ,! fir/ day ( ! n9ete5? c5tury1 ,janu>y #a1 #ahja1 0 signalis$ by ! discov]y ( a small planet by ,,piazzi4 ,! new object 0 lo/ = a "t1 b x 0 r$etect$ on ,decemb] #ca ( ! same ye>4 ,?is planet lay betwe5 ! orbits ( ,m>s & ,jupit]--a region 9 :i* _m hundr$s ( o!r small bodies h s9ce be5 f\nd4 ,! fir/ ( ^! m9or planets 0 call$ ,c]es2 ! next ?ree to be discov]$ are kn[n z ,pallas1 ,juno1 & ,ve/a4 ,beside ^! f\r1 two o!rs are ( special int]e/3 "o1 ,eros1 :i* comes ne>] ! ,sun ?an ! orbit ( ,m>s--inde$ at "s oppositions x approa*es ! ,e>? )9 #ac1jjj1jjj miles1 & is !re=e1 next to ! ,moon1 our ne>e/ neighb\r 9 space2 ! o!r1 ,a*illes1 moves at a di/ance f ! ,sun equal to t ( ,jupit]4 ,c]es is mu* ! l>ge/ ( all ! m9or planets2 inde$ is l>g] ?an all ! o!rs put toge!r4 ,yet ! ,e>? exce$s ,c]es #djjj times 9 volume1 & #gjjj times 9 mass1 & ! entire sw>m ( m9or planets1 all put toge!r1 w\ld n equal 9 total volume "o-fiftie? "p ( ! ,moon4 ,! se>* = ^! small bodies r5d]$ x necess>y t mu* full] & m accurate maps ( ! />s %\ld be made ?an _h hi!rto be5 attempt$1 & ?is _h an important be>+ on ! next great ev5t 9 ! developm5t ( gravitational a/ronomy4 #ci ,! movem5ts ( ,uranus soon gave rise to difficulties4 ,x 0 f\nd impossible1 satisfactorily1 to reconcile ! e>li] & lat] obs]vations1 & 9 ! tables ( ,uranus1 publi%$ by ,,b\v>d 9 #ahba1 ! e>li] obs]vations 7 reject$4 ,b ! discrepancies betwe5 ! obs]v$ & calculat$ places = ! planet soon began to reappe> & quickly increase1 & ! sugge/ion 0 made t ^! discrepancies 7 due to an attraction ex]cis$ by "s planet z yet unkn[n4 ,?us ,mrs4 ,som]ville 9 a little book on ! connection ( ! physical sci5ces1 publi%$ 9 #ahcf1 wrote1 ,possibly x 7t is1 ,uranus7 may be subject to di/urbances f "s unse5 planet revolv+ ab\t ! ,sun beyond ! pres5t b\nd>ies ( our sy/em4 ,if1 aft] ! lapse ( ye>s1 ! tables =m$ f a comb9ation ( num]\s obs]vations %\ld /ill be inadequate to repres5t ! motions ( ,uranus1 ! discrepancies may reveal ! exi/5ce1 nay1 ev5 ! mass & orbit ( a body plac$ = ev] beyond ! sph]e ( vision4 ,9 #ahdc ,,john ,c4 ,,adams1 :o _h j graduat$ z ,s5ior ,wrangl] at ,cambridge1 proce$$ to attack ! problem ( det]m9+ ! position1 orbit1 & mass ( ! unkn[n body by :i* on ?is assumption ,uranus 0 di/urb$1 f ! irregul>ities evid5t 9 ! motion ( t planet4 ,! problem 0 "o ( extraord9>y intricacy1 b by ,septemb] #ahde ,adams _h obta9$ a fir/ solution1 :i*1 he submitt$ to ,,airy1 ! ,a/ronom] ,royal4 ,z1 h[ev]1 he neglect$ to reply to "s inquiries made by ,airy1 no se>* = ! new planet 0 in/itut$ 9 ,engl& until ! results ( a new & indep5d5t work] _h be5 publi%$4 ,! same problem _h be5 attack$ by a well-kn[n & v gift$ ,fr5* ma!matician1 ,u4 ,j4 ,j4 ,,lev]ri]1 & #dj 9 ,june #ahdf he publi%$ 8 position = ! unse5 planet1 :i* prov$ to be 9 close accord ) t :i* ,adams _h furni%$ to ,airy n9e mon?s be=e4 ,on ?is ,airy /irr$ up ,*allis1 ! ,director ( ! ,cambridge ,obs]vatory1 :i* !n possess$ ! mo/ p[]ful telescope 9 ,engl&1 to se>* = ! planet1 & ,*allis comm5c$ to make *>ts1 :i* includ$ m ?an #cjjj />s1 9 ord] to make sure t ! /rang] %\ld n escape 8 net4 ,lev]ri]1 on ! o!r h&1 communicat$ 8 result to ! ,b]l9 ,obs]vatory1 :]e !y _h j receiv$ "s ( ! /> *>ts prep>$ by ,dr4 ,bremik] 9 connection ) ! se>* = m9or planets4 ,! ,b]l9 obs]v]1 ,dr4 ,galle1 _h !re=e no?+ to d b to comp>e ! />s 9 ! field1 ^u :i* he turn$ 8 telescope1 ) ^? %[n on ! *>t2 a /> n 9 ! *>t w\ld probably be ! desir$ /rang]4 ,he f\nd x1 !re=e1 on ! v fir/ ev5+1 ,septemb] #bc1 #ahdf1 )9 less ?an f\r diamet]s ( ! ,moon ( ! pr$ict$ place4 ,! same object _h be5 obs]v$ by ,*allis at ,cambridge on ,augu/ #d & #ab1 b he 0 def]r+ ! r$uction ( 8 obs]vations until he _h complet$ 8 scrut9y ( ! zone1 & h5ce _h n recognis$ x z diff]5t f an ord9>y />4 ,?is discov]y ( ! planet n[ kn[n z ,neptune1 :i* _h be5 di/urb+ ! movem5t ( ,uranus1 has rightly be5 reg>d$ z ! mo/ brilliant triumph ( gravitational a/ronomy4 ,x 0 ! legitimate cr[n ( t long intellectual /ruggle :i* _h comm5c$ m ?an #bjjj ye>s e>li]1 :5 ! fir/ ,greek a/ronom]s set !mselves to unravel ! app>5tly aimless w&]+s ( ! planets 9 ! assur$ fai? t !y w\ld f9d !m ob$i5t unto law4 #da ,b ( :at use 0 all ?is ef=t8 ,:at is ! good ( a/ronomy8 ,! "q is (t5 ask$1 b x is ! "q ( ignorance4 ,! use ( a/ronomy is ! developm5t :i* x has giv5 to ! intellectual p[]s ( man4 ,directly ! problem ( ! planet>y motions 0 fir/ attempt$1 x became necess>y to initiate ma!matical processes 9 ord] to deal ) x1 & ! necessity = ! cont9u$ developm5t ( ma!matics has be5 felt 9 ! same connection "r d[n to ! pres5t day4 ,:5 ! ,greek a/ronom]s fir/ began _! inquiries into ! planet>y movem5ts !y hop$ = no mat]ial ga91 & !y receiv$ none4 ,!y lab\r$2 we h ent]$ into _! lab\rs4 ,b ! :ole ( our va/ advances 9 me*anical & eng9e]+ sci5ce--advances :i* m ?an any?+ else diff]5tiate ?is our pres5t age f all ^? :i* h prec$$ x--are built ^u our comm& ( ma!matics & our k ( ! laws ( motion--a comm& & a k :i* we owe directly to _! p]sev]+ attempts to advance ! sci5ce ( a/ronomy1 & to foll[ aft] k1 n = any mat]ial rew>ds :i* %e _h to (f]1 b = h] own sake4 #db ,,*apt] ,,iv ,,a/ronomical ,,measurem5ts ,! old prov]b has x t ,sci5ce is measurem5t1 & ( none ( ! sci5ces is ?is s true z ( ! sci5ce ( a/ronomy4 ,inde$ ! measurem5t ( "t by obs]vation ( ! movem5ts ( ! heav5ly bodies 0 ! beg9n+ ( a/ronomy4 ,! movem5t ( ! ,sun gave ! day1 :i* 0 reckon$ to beg9 ei!r at sunrise or at sunset4 ,! *anges ( ! ,moon gave ! mon?1 & 9 _m languages ! root mean+ ( ! ^w = ,moon is measur]4 ,! app>5t movem5t ( ! ,sun among/ ! />s gave a yet long] division ( "t1 ! ye>1 :i* c\ld be det]m9$ 9 a numb] ( diff]5t ways1 ei!r f ! ,sun alone1 or f ! ,sun toge!r ) ! />s4 ,a v simple & anci5t =m ( in/rum5t = measur+ ?is movem5t ( ! ,sun 0 ! obelisk1 a pill> ) a po9t$ top set up on a level pavem5t4 ,su* obelisks 7 common 9 ,egypt1 & "o ( ! mo/ celebrat$1 kn[n z ,cleopatra's ,ne$le1 n[ /&s on ! ,?ames ,embankm5t4 ,z ! ,sun mov$ 9 ! sky1 ! %ad[ ( ! pill> mov$ on ! pavem5t1 & midday1 or noon1 0 m>k$ :5 ! %ad[ 0 %orte/4 ,! l5g? ( ! %ad[ at noon v>i$ f day to day2 x 0 %orte/ at mid-summ]1 & longe/ at midw9t]1 i4e4 at ! summ] & w9t] sol/ices4 ,twice 9 ! ye> ! %ad[ ( ! pill> po9t$ due we/ at sunrise1 & due ea/ at #dc sunset--t is to say1 ! %ad[ at ! beg9n+ ( ! day 0 9 ! same /raight l9e z at its end4 ,^! two days m>k$ ! two equ9oxes ( spr+ & autumn4 ,! obelisk 0 a simple means ( measur+ ! height & position ( ! ,sun1 b x _h its drawbacks4 ,! l5g? ( ! %ad[ & its direction did n v>y by equal am\nts 9 equal times1 & if ! pavem5t ^u :i* ! %ad[ fell 0 divid$ by m>ks correspond+ to equal int]vals ( "t = "o day ( ! ye>1 ! m>ks did n s]ve = all o!r days4 ,b if = ! pill> a triangul> wall 0 sub/itut$--a wall ris+ f ! pavem5t at ! s\? & slop+ up t[>ds ! nor? at su* an angle t x seem$ to po9t to ! invisible pivot ( ! heav5s1 r\nd :i* all ! />s appe>$ to revolve--!n ! %ad[ ( ! wall mov$ on ! pavem5t 9 ! same mann] e day1 & ! pavem5t if m>k$ to %[ ! h\rs = "o day w\ld %[ !m = any day4 ,! sundials /ill (t5 f\nd 9 ! g>d5s ( c\ntry h\ses or 9 *ur*y>ds are m9iatures ( su* an in/rum5t4 ,b ! ,greek a/ronom]s devis$ o!r & bett] me?ods = det]m9+ ! positions ( ! heav5ly bodies4 ,obelisks or dials 7 ( use only ) ! ,sun & ,moon :i* ca/ %ad[s4 ,to det]m9e ! position ( a />1 sights l ^? ( a rifle 7 employ$1 & ^! 7 fix$ to circles :i* 7 c>efully divid$1 g5]ally into #cfj degrees4 ,z !re are #cfe days 9 a ye>1 & z ! ,sun makes a complete circuit ( ! ,zodiac 9 ?is "t1 x moves v ne>ly a degree 9 a day4 ,! twelve ,signs ( ! ,zodiac are !re=e ea* #cj 9 l5g?1 & ea* #dd takes on ! av]age a d\ble-h\r to rise or set4 ,:ile ! ,sun & ,moon are ea* ab\t half a degree 9 diamet]1 i4e4 ab\t "o-sixtie? ( ! l5g? ( a ,sign1 & !re=e take a d\ble-m9ute to rise or set4 ,ea* degree ( a circle is !re=e divid$ into #fj m9utes1 & ea* m9ute may be divid$ into #fj seconds4 ,z ! ,sun or ,moon are ea* ab\t half a degree1 or1 m exactly1 #cb m9utes 9 diamet]1 x is cle> t1 s long z a/ronomical obs]vations 7 made by ! unaid$ sight1 a m9ute ( arc 7writt5 #a'7 0 ! smalle/ division ( ! circle t c\ld be us$4 ,a cord or wire c inde$ be detect$ :5 se5 project$ aga9/ a mod]ately bright backgr\nd if its ?ickness is a second ( arc 7writt5 #a7--;a sixtie? ( a m9ute--b ! wire is m]ely p]ceiv$1 n prop]ly def9$4 ,ty*o ,brahe _h a*iev$ ! utmo/ t c\ld be done by ! nak$ eye1 & x 0 ! c]ta9ty t he c\ld n h made a mi/ake 9 an obs]vation 9 ! place ( ! planet ,m>s am\nt+ to z mu* z #h m9utes ( arc--t is to say1 ( a qu>t] ! app>5t diamet] ( ! ,moon--t made ,kepl] f9ally give up all attempts to expla9 ! planet>y movem5ts on ! doctr9e ( circul> orbits & to try movem5ts 9 an ellipse4 ,b a contempor>y ( ,kepl]1 z gift$ z he 0 himself1 b 9 a diff]5t direction1 0 ! means ( increas+ ! obs]v+ p[] ( ! a/ronom]4 ,,galileo ,,galilei 7#aefd-afdb71 ( a noble ,flor5t9e family1 0 appo9t$ ,lectur] 9 ,ma!matics at ! ,univ]sity ( ,pisa4 ,"h he soon di/+ui%$ himself by 8 orig9ality ( ?\ght1 & ! +5uity & decisiv5ess ( 8 exp]im5ts4 ,up to t "t x _h be5 taught t ( #de two bodies ! heavi] w\ld fall to ! gr\nd m quickly ?an ! light]4 ,galileo let fall a #ajj-lb4 weight & a #a-lb4 weight f ! top ( ! ,lean+ ,t[]1 & bo? weights rea*$ ! pavem5t toge!r4 ,by ?is & o!r +5i\s exp]im5ts he laid a firm f\ndation = ! sci5ce ( me*anics1 & he discov]$ ! laws ( motion :i* ,newton aft]w>ds =mulat$4 ,he he>d t an in/rum5t _h be5 inv5t$ 9 ,holl& :i* seem$ to br+ di/ant objects ne>]1 &1 hav+ himself a consid]able k ( optics1 x 0 n long be=e he made himself a little telescope4 ,he fix$ two spectacle glasses1 "o = long & "o = %ort sight1 9 a little old organ-pipe1 & ?us made = himself a telescope :i* magnifi$ ?ree times4 ,be=e long he _h made ano!r :i* magnifi$ ?irty times1 &1 turn+ x t[>ds ! heav5ly bodies1 he discov]$ d>k mov+ spots ^u ! ,sun1 m\nta9s & valleys on ! ,moon1 & f\r small satellites revolv+ r\nd ,jupit]4 ,he also p]ceiv$ t ,v5us %[$ phases--t is to say1 %e *ang$ h] app>5t %ape j z ! ,moon does--& he f\nd ! ,milky ,way to be compos$ ( an imm5se numb] ( small />s4 ,^! discov]ies 7 made 9 ! ye>s #afji-aa4 ,a telescope consi/s 9 pr9ciple ( two p>ts--an object-glass1 to =m an image ( ! di/ant object1 & an eye-piece1 to magnify x4 ,! rays ( light f ! heav5ly body fall on ! object-glass1 & are s b5t out ( _! c\rse by x z to be br\ght toge!r 9 a po9t call$ ! focus4 ,! light-ga!r+ p[] ( ! telescope1 !re=e1 dep5ds ^u ! size ( ! object-glass1 & is proportional to its area4 ,b ! size ( ! image dep5ds ^u ! focal l5g? ( ! telescope1 i4e4 ^u ! di/ance t ! focus #df is f ! object-glass4 ,?us a small disc1 an in* 9 diamet]--su* z a halfp5ny--w exactly cov] ! full ,moon if held up n9e feet away f ! eye2 & necess>ily ! image ( ! full ,moon made by an object-glass ( n9e-feet focus w be an in* 9 diamet]4 ,! eye-piece is a magnify+-glass or small microscope appli$ to ?is image1 & by x ! image c be magnifi$ to any desir$ am\nt :i* ! quality ( ! object-glass & ! /ead9ess ( ! atmosph]e may p]mit4 ,?is little image ( ! ,moon1 planet1 or gr\p ( />s l5t itself to measurem5t4 ,a "y ,engli% g5tleman1 ,,gascoigne1 :o aft]w>ds fell at ! ,battle ( ,m>/on ,moor1 devis$ ! micromet] = ?is purpose4 ,! micromet] usually has two frames1 ea* c>ry+ "o or m v ?9 ?reads--usually spid]'s ?reads--& ! frames c be mov$ by v f9e screws1 ! numb] ( turns or p>ts ( a turn ( ea* screw be+ read (f on suitable scales4 ,by plac+ "o ?read on ! image ( "o />1 & ! o!r on ! image ( ano!r1 ! app>5t sep>ation ( ! two c be readily & precisely measur$4 ,)9 ! la/ ?irty ye>s photography has imm5sely increas$ ! ease ) :i* a/ronomical measurem5ts c be made4 ,! s5sitive photographic plate is plac$ 9 ! focus ( ! telescope1 & ! light ( ,sun1 ,moon1 or />s1 accord+ to ! object to :i* ! telescope is direct$1 makes a p]man5t impression on ! plate4 ,?us a picture is obta9$1 :i* c be exam9$ & measur$ 9 detail at any conv5i5t "t aft]w>ds2 a portion ( ! heav5s is1 z x 71 br\ght actually d[n to ! a/ronom]'s /udy4 ,x 0 long be=e ?is great advance 0 effect$4 #dg ,! fir/ telescopes 7 v imp]fect1 = ! rays ( diff]5t col\r proce$+ f any planet or /> came to diff]5t foci1 s t ! image 0 col\r$1 diffus$1 & ill-def9$4 ,! fir/ me?od by :i* ?is difficulty 0 dealt ) 0 by mak+ telescopes ( enorm\sly long focal l5g?2 #hj1 #ajj1 or #aej feet 7 n uncommon1 b ^! 7 at once cumb]some & un/eady4 ,sir ,isaac ,newton !re=e disc>d$ ! use ( object-glasses1 & us$ curv$ mirrors 9 ord] to =m ! image 9 ! focus1 & succe$$ 9 mak+ two telescopes on ?is pr9ciple ( reflection4 ,o!rs foll[$ 9 ! same direction1 & a c5tury lat] ,sir ,,william ,,h]s*el 0 mo/ skilful & successful 9 mak+ reflectors1 8 l>ge/ be+ #dj feet 9 focal l5g?1 & ?us giv+ an image ( ! ,moon 9 its focus ( ne>ly #d- in*es diamet]4 ,b 9 #agbi ,,*e/] ,,moor ,,hall f\nd t by comb9+ two suitable l5ses toge!r 9 ! object-glass he c\ld get ov] mo/ ( ! col\r difficulty1 & 9 #ageh ! optician ,,dollond began to make object-glasses t 7 almo/ free f ! col\r defect4 ,f t "t onw>d ! manufacture ( refractors1 z object-glass telescopes are call$1 has improv$2 ! glass has be5 made m transp>5t & m p]fect 9 quality1 & l>g] 9 size1 & ! figure ( ! l5s improv$4 ,! l>ge/ refractor n[ 9 use is t ( ! ,y]kes ,obs]vatory1 ,wiscons91 ,u4,s4,a41 & is #dj in*es 9 ap]ture1 ) a focal l5g? ( #fe feet1 s t ! image ( ! ,moon 9 its focus has a diamet] ( m ?an #g in*es4 ,at pres5t ?is seems to m>k ! limit ( size = refractors1 & ! difficulty ( gett+ good en\gh glass = s l>ge a l5s is v great inde$4 ,reflectors h !re=e come aga9 into fav\r1 z mirrors c be made l>g] #dh ?an any object-glass4 ,?us ,"l ,rosse's great telescope 0 #f feet 9 diamet]2 & ! mo/ p[]ful telescope n[ 9 action is ! great #e-;foot mirror ( ! ,mt4 ,wilson ,obs]vatory1 ,cali=nia1 ) a focal l5g?1 z sometimes us$1 ( #aej feet4 ,?us its light-ga!r+ p[] is ab\t #fj1jjj times t ( ! unaid$ eye1 & ! full ,moon 9 its focus is #ag in*es 9 diamet]2 su* is ! enorm\s increase to man's p[] ( sight1 & consequ5tly to 8 p[] ( le>n+ ab\t ! heav5ly bodies1 :i* ! developm5t ( ! telescope has af=d$ to him4 ,! measurem5t ( "t 0 ! fir/ purpose = :i* m5 wat*$ ! heav5ly bodies2 a second purpose 0 ! measurem5t ( ! size ( ! ,e>?4 ,if at "o place a /> 0 obs]v$ to pass exactly ov]head1 & if at ano!r1 due s\? ( x1 ! same /> 0 obs]v$ to pass ! m]idian "o degree nor? ( ! z5i?1 !n by measur+ ! di/ance betwe5 ! two places ! circumf]5ce ( ! :ole ,e>? w\ld be kn[n1 = x w\ld be #cfj times t am\nt4 ,9 ?is way ! size ( ! ,e>? 0 r\ghly asc]ta9$ #bjjj ye>s be=e ! inv5tion ( ! telescope4 ,b ) ! telescope measures ( mu* great] precision c\ld be made1 & h5ce f> m difficult problems c\ld be attack$4 ,"o great practical problem 0 t ( f9d+ out ! position ( a %ip :5 out ( sight ( l&4 ,! anci5t ,pho5ician & ,greek navigators _h mo/ly conf9$ !mselves to coa/+ voyages along ! %ores ( ! ,m$it]ranean ,sea1 & !re=e ! quick recognition ( l&m>ks 0 ! fir/ requisite = a good sailor4 ,b :51 9 #adib1 ,columbus _h br\ght a new cont95t to light1 & long voyages 7 freely tak5 across ! great oceans1 x became an urg5t #di necessity = ! navigator to f9d out 8 position :5 he _h be5 out ( sight ( any l&m>k = weeks4 ,?is necessity 0 especially felt by ! nations ( ,we/]n ,europe1 ! c\ntries fac+ ! ,atlantic ) ! ,new ,_w on its f>-di/ant o!r %ore4 ,spa91 ,france1 ,engl&1 & ,holl&1 all 7 eag] competitors = a grasp on ! new l&s1 & !re=e 7 e>ne/ 9 seek+ a solution ( ! problem ( navigation4 ,! latitude ( ! %ip c\ld be f\nd out by obs]v+ ! height ( ! ,sun at noon1 or ( ! ,pole ,/> at night1 or 9 sev]al o!r ways4 ,b ! longitude 0 m difficult4 ,z ! ,e>? turns on its axis1 diff]5t portions ( its surface are br\ght 9 succession "u ! ,sun1 & if we take ! mom5t :5 ! ,sun is on ! m]idian ( any place z its noon1 z twelve o'clock = t place1 !n ! diff]5ce ( longitude betwe5 any two places is ess5tially ! diff]5ce 9 _! local times4 ,x 0 possible = ! sailor to f9d out :5 x 0 local noon = him1 b h[ c\ld he possibly f9d out :at "t x 0 at t mom5t at ! port f :i* he _h sail$1 p]haps sev]al weeks be=e8 ,! ,moon & />s suppli$ ev5tually ! means = giv+ ?is in=mation4 ,= ! ,moon moves among/ ! />s1 z ! h& ( a clock moves among/ ! figures ( a dial1 & x became possible at l5g? to pr$ict = long 9 advance exactly :]e among/ ! />s ! ,moon w\ld be1 = any giv5 "t1 ( any select$ place4 ,:5 ?is me?od 0 fir/ sugge/$1 h[ev]1 nei!r ! motion ( ! ,moon nor ! places ( ! pr9cipal />s 7 kn[n ) suffici5t accuracy1 & x 0 to rem$y ?is defect1 & put navigation ^u #ej a s\nd basis1 t ,,*>les ,,ii4 f\nd$ ,gre5wi* ,obs]vatory 9 ! ye> #afge1 & appo9t$ ,,flam/e$ ! fir/ ,a/ronom] ,royal4 ,9 ! ye> #agfg ,,maskelyne1 ! fif? ,a/ronom] ,royal1 br\ght out ! fir/ volume ( ! ,nautical ,almanac1 9 :i* ! positions ( ! ,moon relative to c]ta9 />s 7 giv5 = regul> int]vals ( ,gre5wi* "t4 ,mu* ab\t ! same p]iod ! problem 0 solv$ 9 ano!r way by ! inv5tion ( ! *ronomet]1 by ,,john ,,h>rison1 a ,york%ire c>p5t]4 ,! *ronomet] 0 a l>ge wat*1 s con/ruct$ t its rate 0 n greatly alt]$ by heat or cold1 s t ! navigator _h ,gre5wi* "t ) him :]ev] he w5t4 ,! new me?od 9 ! h&s ( ,,capta9 ,,cook & o!r great navigators l$ to a rapid developm5t ( navigation & ! discov]y ( ,au/ralia & ,new ,zeal&1 & a numb] ( isl&s 9 ! ,pacific4 ,! build+ up ( ! va/ oceanic comm]ce ( ,great ,brita9 & ( h] great colonial empire1 bo? 9 ,nor? ,am]ica & 9 ! ,s\!rn ,oceans1 has aris5 out ( ! "w ( ! ,royal ,obs]vatory1 ,gre5wi*1 & has _h a real & intimate connection ) x4 ,to obs]ve ! motions ( ! ,moon1 ,sun1 & planets1 & to det]m9e ) ! greate/ possible precision ! places ( ! />s h be5 ! programme ( ,gre5wi* ,obs]vatory f its f\ndation to ! pres5t "t4 ,o!r great national obs]vatories h be5 ,cop5hag51 f\nd$ 9 #afcg2 ,p>is1 9 #affg2 ,b]l91 9 #agjj2 ,/4 ,pet]sburg1 9 #agbe1 sup]s$$ by t ( ,pulk[a1 9 #ahci2 & ,wa%+ton1 9 #ahdb2 :ile n a few ( ! great univ]sities h also effici5t obs]vatories connect$ ) !m4 ,( ! directly practical results ( a/ronomy1 ! #ea promotion ( navigation /&s 9 ! fir/ rank4 ,b ! sci5ce has nev] be5 limit$ to m]ely utilit>ian inquiries1 & ! problem ( measur+ cele/ial di/ances has foll[$ on inevitably f ! measurem5t ( ! ,e>?4 ,! fir/ di/ance to be attack$ 0 t ( ! ne>e/ companion to ! ,e>?1 i4e4 ! ,moon4 ,x (t5 happ5s on our own planet t x is requir$ to f9d ! di/ance ( an object beyond our rea*4 ,?us a g5]al on ! m>* may come to a riv] & ne$ to "k exactly h[ broad x is1 t he may prep>e ! means = bridg+ x4 ,su* problems are usually solv$ on ! foll[+ pr9ciple4 ,let ,a be ! di/ant object4 ,!n if ! direction ( ,a be obs]v$ f ea* ( two /ations1 ,b & ,c1 & ! di/ance ( ,b f ,c be measur$1 x is possible to calculate ! di/ances ( ,a f ,b & f ,c4 ,! application ( ?is pr9ciple to ! measurem5t ( ! ,moon's di/ance 0 made by ! e/abli%m5t ( an obs]vatory at ! ,cape ( ,good ,hope1 to co-op]ate ) t ( ,gre5wi*4 ,x is1 ( c\rse1 n possible to see ,gre5wi* ,obs]vatory f ! ,cape1 or vice v]sa1 b ! />s1 be+ at an almo/ inf9ite di/ance1 lie 9 ! same direction f bo? obs]vatories4 ,:at is requir$ !n is to measure ! app>5t di/ance ( ! ,moon f ! same />s z se5 f ,gre5wi* & z se5 f ! ,cape1 &1 ! di/ance ap>t ( ! two obs]vatories be+ kn[n1 ! di/ance ( ! ,moon c be calculat$4 ,?is 0 a comp>atively easy problem4 ,! next /ep 9 cele/ial measurem5t 0 f> h>d]2 x 0 to f9d ! di/ance ( ! ,sun4 ,! ,sun is #djj times z f> (f z ! ,moon1 & !re=e x seems to be practically 9 ! same direction z se5 f ea* ( #eb ! two obs]vatories1 &1 be+ s bright1 />s _c be se5 ne> x 9 ! telescope4 ,b by c>efully wat*+ ! app>5t movem5ts ( ! planets _! relative di/ances f ! ,sun c be asc]ta9$1 & 7 kn[n long be=e x 0 ?\ght possible t we %\ld ev] "k _! real di/ances4 ,?us ,v5us nev] appe>s to travel m ?an #dg #ae' f ! ,sun4 ,?is means t h] di/ance f ! ,sun is a little m ?an sev5-t5?s ( t ( ! ,e>?4 ,if1 !re=e1 ! di/ance ( "o planet f ! ,sun c be measur$1 or ! di/ance ( "o planet f ! ,e>?1 ! actual di/ances ( all ! planets w foll[4 ,we "k ! proportions ( ! p>ts ( ! sol> sy/em1 &1 if we c fix ! scale ( "o ( ! p>ts1 we fix ! scale ( all4 ,x has be5 f\nd possible to det]m9e ! di/ance ( ,m>s1 ( sev]al ( ! m9or planets1 & especially ( ,eros1 a v small m9or planet t sometimes comes )9 #ac1jjj1jjj miles ( ! ,e>?1 or sev5 times ne>] to u ?an is ! ,sun4 ,f ! measures ( ,eros1 we h le>n$ t ! ,sun is sep>at$ f u by v ne>ly #ic1jjj1jjj miles--an unimag9able di/ance4 ,p]haps ! ne>e/ way ( gett+ "s conception ( ?is va/ int]val is by rememb]+ t !re are only #ca1eef1ibf seconds ( "t 9 a ye>4 ,if1 !re=e1 an express tra91 travell+ #fj miles an h\r--a mile a m9ute--set out = ! ,sun1 & travell$ day & night )\t cease1 x w\ld take m ?an #ahj ye>s to accompli% ! j\rney4 ,b ?is a/ronomical measure has l$ on to "o m d>+ /ill4 ,! e>? is on "o side ( ! ,sun 9 ,janu>y1 on ! o!r 9 ,july4 ,at ^! two dates1 !re=e1 we are occupy+ /ations #ahf1jjj1jjj miles #ec ap>t1 & c asc]ta9 ! app>5t diff]5ce 9 direction ( ! />s z view$ f ! two po9ts ,b ! a/oni%+ result is t ?is enorm\s *ange 9 ! position ( ! ,e>? makes n ! slighte/ obs]vable diff]5ce 9 ! position ( mo/ ( ! />s4 ,a few1 a v few1 d %[ a v slight diff]5ce4 ,! ne>e/ /> to u is ab\t #bhj1jjj times z f> f u z ! ,sun2 ?is is ,alpha ,c5tauri1 ! brighte/ /> 9 ! con/ellation ( ! ,c5taur & ! ?ird brighte/ /> 9 ! sky4 ,sirius1 ! brighte/ />1 is twice ?is di/ance4 ,"s =ty or fifty />s h _h _! di/ances r\ghly det]m9$2 b ! />s 9 g5]al f> transc5d all our attempts to plumb _! di/ances4 ,b1 f c]ta9 indirect h9ts1 x is g5]ally suppos$ t ! mass ( />s 9 ! ,milky ,way are some?+ l #cjj1jjj1jjj times z f> f u z we are f our ,sun4 ,?us f>1 !n1 a/ronomy has l$ u 9 ! direction or measurem5t4 ,x has enabl$ u to measure ! size ( ! ,e>? ^u :i* we live1 & to f9d out ! position ( a %ip 9 ! mid/ ( ! trackless ocean4 ,x has also enabl$ u to ca/ a s\nd+-l9e into space1 to %[ h[ remote & solit>y ! e>? moves ?r\gh ! void1 & to :at unimag9able l5g?s ! great /ell> univ]se1 ( :i* x =ms a seclud$ atom1 /ret*es out t[>ds inf9ity4 #ed ,,*apt] ,v ,,! ,,memb]s ,,( ,,! ,,sol> ,,sy/em ,a/ronomical measurem5t has n only giv5 u ! di/ances ( ! v>i\s planets f ! ,sun2 x has also furni%$ u1 z 9 ! annex$ table1 ) _! real diamet]s1 &1 z a consequ5ce ( ! law ( gravitation1 ) _! d5sities & weights1 & ! =ce ( gravity at _! surfaces4 ,& ^! num]ical details are ( ! fir/ importance 9 direct+ u z to ! inf]5ces t we ought to draw z to _! pres5t physical conditions4 ,! !ory ( ,cop]nicus depriv$ ! ,e>? ( its special position z ! immovable c5tre ( ! univ]se1 b rais$ x to ! rank ( a planet4 ,x is !re=e a heav5ly body1 yet ne$s no telescope to br+ x )9 our k52 bad wea!r does n hide x f u1 b r %[s x to u "u new conditions4 ,we f9d x to be a globe ( l& & wat]1 cov]$ by an atmosph]e 9 :i* float *ang+ cl\ds2 we h mapp$ x1 & we f9d t ! l& & wat] are always !re1 b _! relations are n q fix$2 !re is give & take betwe5 !m4 ,we h f\nd ( :at elem5ts ! l& & wat] consi/1 & h[ ^! elem5ts comb9e ) ea* o!r or dissociate4 ,9 a ^w1 ! ,e>? is ! heav5ly body t we "k ! be/1 & ) x we mu/ comp>e & contra/ all ! o!rs4 ,be=e ! inv5tion ( ! telescope !re 7 b #ee two o!r heav5ly bodies--! ,sun & ! ,moon--t appe>$ z orbs %[+ visible discs1 & ev5 9 _! cases no?+ c\ld be satisfactorily made out z to _! conditions4 ,n[ ea* ( ! five planets kn[n to ! anci5ts reveals to u 9 ! telescope a measurable disc1 & we c detect significant details on _! surfaces4 ,,! ,,moon is ! "o object 9 ! heav5s :i* does n disappo9t a novice :5 he fir/ sees x 9 ! telescope4 ,e detail is h>d1 cle>-cut1 & %>p2 x is manife/ t we are look+ at a globe1 a v r\gh globe1 ) hills & m\nta9s1 pla9s & valleys1 ! :ole 9 su* di/9ct relief t x seems z if x might be t\*$4 ,no cl\ds ev] conceal its details1 no mi/ ev] s(t5s its outl9es2 !re are no half-lights1 its %ad[s are dead black1 its high lights are molt5 silv]4 ,c]ta9 *anges ( illum9ation g on ) ! advanc+ age ( ! ,moon1 z ! cresc5t broad5s out to ! half1 ! half to ! full1 & ! full1 9 its turn1 wanes away2 b ! lun> day is ne>ly ?irty times z long z t ( ! ,e>?1 & ^! *anges proce$ b sl[ly4 ,! full ,moon1 z se5 by ! nak$ eye1 %[s sev]al vague d>k spots1 :i* mo/ p agree to fancy z l ! eyes1 nose1 & m\? ( a broad1 sorr[ful face4 ,! ord9>y a/ronomical telescope inv]ts ! image1 s ! eyes ( ! ,moon are se5 9 ! l[] "p ( ! field ( ! telescope z a s]ies ( dusky pla9s /ret*+ "r across ! disc4 ,b 9 ! upp] "p1 ne> ! left-h& corn] ( ! und]lip1 !re is a bright1 r\nd spot1 f :i* a numb] ( bright /reaks radiate--sugge/+ a peel$ orange ) its /alk1 & ! l9es m>k+ ! sections radiat+ f x4 ,?is bright spot has be5 call$ aft] ! great #ef ,mean di/ance f ,sun4 ,p]iod ,velocity ,class4 ,"n4 ,e>?'s ,9 millions ( revolution4 9 orbit4 ,ecc5tricity4 di/ance ( miles4 ,9 ye>s4 ,miles p] #a4 sec4 ,t]re/rial ,m]cury #j4chg #cf4j #j4bd #bi4g #j4bjef ,planets ,v5us #j4gbc #fg4b #j4fb #ba4i #j4jjfh ,e>? #a4jjj #ib4i #a4jj #ah4e #j4jafh ,m>s #a4ebd #ada4e #a4hh #ae4j #j4jicc ,m9or ,eros #a4deh #ace4e #a4gf #ae4e #j4bbbh ,planets ,c]es #b4gfg #beg4a #d4fj #aa4a #j4jgfc ,a*illes #e4bec #dhh4j #ab4jd #h4a #j4jeji ,major ,jupit] #e4bjc #dhc4c #aa4hf #h4a #j4jdhc ,planets ,saturn #i4eci #hhf4f #bi4df #f4j #j4jefa ,uranus #ai4ahc #agha4i #hd4jb #d4b #j4jdfc ,neptune #cj4jee #bgia4f #afd4gh #c4d #j4jjij #eg ,mean diamet]4 ,surface4 ,volume4 ,mass4 ,"n4 ,symbol4 ,9 miles4 ,e>?#a4 ,e>?#a4 ,e>?#a4 ,e>?#a4 ,sun ,sun #hffdjj #aji4dbb #aaigc4 #acajacj4 #ccbjjj4 ,moon ,moon #bafc #j4bgc #j4jge #j4jb #j4jab ,m]cury ,m]cury #cjcj #j4chc #j4adg #j4jf #j4jdh ,v5us ,v5us #ggjj #j4igb #j4ide #j4ib #j4hbj ,e>? ,e>? #giah #a4jjj #a4jjj #a4jj #a4jjj ,m>s ,m>s #dbcj #j4ecd #j4bhe #j4ae #j4ajg ,jupit] ,jupit] #hfejj #aj4ibd #aai4c #acjd4 #cag4g ,saturn ,saturn #gcjjj #i4bai #he4j #ghc4 #id4h ,uranus ,uranus #caijj #d4jbi #af4b #fe4 #ad4f ,neptune ,neptune #cdhjj #d4cie #ai4c #he4 #ag4j #eh ,light ,gravity4 & heat ,alb$o2 ,d5sity4 ,fall 9 receiv$ i4e4 re- ,e>? ,wat] ,e>? feet p] f ,sun4 ,"t ( rotation flect+ ,"n4 #a4 #a4 #a4 sec4 ,e>?#a4 on axis4 p[]4 d4 h4 m4 ,sun #j4be #a4ci #bg4fe #ddd4fj 444 #be #d #dh 444 ,moon #j4fa #c4ci #j4ag #b4gc #a4jj #bg #g #dc #j4ag d4 h4 m4 s4 ,m]cury #j4he #d4gb #j4dc #f4ia #f4fg #hh 787 #j4ad ,v5us #j4hi #d4id #j4hb #ac4ai #a4ia #bc #ba #bc 787 #j4gf ,e>? #a4jj #e4ee #a4jj #af4jh #a4jj #bc #ef #d #j4ej 787 ,m>s #j4ga #c4ib #j4ch #f4aa #j4dc #bd #cg #bc #j4bb h4 m4 ,jupit] #j4bd #a4cb #b4fe #db4fa #j4jcg #i #ee #j4fb ,saturn #j4ac #j4gb #a4ah #ah4ig #j4jaa #aj #ad #j4gb ,uranus #j4bb #a4bb #j4ij #ad4dg #j4jjc #i #cj 787 #j4fj ,neptune #j4bj #a4aa #j4hi #ad4ca #j4jja 787 #j4eb #ei ,dani% a/ronom]1 ,ty*o1 & is "o ( ! mo/ conspicu\s objects ( ! full ,moon4 ,! contra/s ( ! ,moon are mu* m pron\nc$ :5 %e is only p>tly lit up4 ,!n ! m\nta9s & valleys /& out 9 ! /ronge/ relief1 & x becomes cle> t ! g5]al type ( =mation on ! ,moon is t ( r+s--r+s ( e conceivable size1 f ! smalle/ po9t t ! telescope c detect up to "s ( ! great dusky pla9s !mselves1 hundr$s ( miles 9 diamet]4 ,^! r+s are s num]\s t ,galileo describ$ ! ,moon z look+ z full ( eyes z a peacock's tail4 ,! "r eye ( ! moonface1 z we see x 9 ! sky1 is =m$ by a va/ dusky pla91 ne>ly z l>ge z ,france & ,g]many put toge!r1 to :i* has be5 giv5 ! "n ( ! ,sea ( ,ra9s 7,m>e ,imbrium71 & j bel[ ?is 7z se5 9 ! telescope7 is "o ( ! mo/ p]fect & beautiful ( all ! lun> r+s--a great r+-pla91 #ef miles 9 diamet]1 call$ aft] ! ?9k] :o revolutionis$ m5's ideas ( ! sol> sy/em1 ,cop]nicus4 ,cop]nicus1 l ,ty*o1 is ! c5tre ( a set ( bright /reaks2 & a neighb\r+ b small] r+1 be>+ ! great "n ( ,kepl]1 /&s 9 a l relation to ano!r set4 ,! mo/ elevat$ region ( ! ,moon is imm$iately 9 ! neighb\rhood ( ! great /alk ( ! orange1 ,ty*o4 ,"h ! r+s are cr[d$ toge!r z closely z !y c be pack$2 m closely 9 _m places1 = !y intrude ^u & ov]lap ea* o!r 9 ! mo/ intricate mann]4 ,a long *a9 ( f9e r+s /ret*es f ?is di/urb$ region ne>ly to ! c5tre ( ! disc1 :]e ! great ,alex&rian a/ronom] is commemorat$ by a va/ wall$ pla91 #fj consid]ably l>g] ?an ! :ole ( ,wales1 & kn[n z ,ptolemu4 ,! di/9ctness ( ! lun> features %[s at once t ! ,moon is 9 an altoge!r diff]5t condition f t ( ! ,e>?4 ,"h ! sky is cont9ually be+ hidd5 by cl\d1 & h5ce ! details ( ! surface ( ! ,e>? z view$ f any o!r planet mu/ (t5 be invisible1 & ev5 :5 actual cl\d is abs5t !re is a m p]man5t veil ( du/1 :i* mu/ greatly s(t5 & confuse t]re/rial outl9es4 ,! cle>ness1 !re=e1 ) :i* we p]ceive ! lun> =mations proves t !re is little or no atmosph]e !re4 ,nor is !re any sign ^u x ( wat]1 ei!r z seas or lakes or runn+ /reams4 ,yet ! ,moon %[s cle>ly t 9 ! pa/ x has gone ?r\gh great & viol5t *anges4 ,! gradation is s complete f ! little crat]lets1 :i* resemble closely1 9 =m & size1 volcanic crat]s on ! ,e>?1 up to ! great r+-pla9s1 l ,cop]nicus or ,ty*o1 or =mations l>g] /ill1 t x seems natural to inf] n only t ! small] crat]s 7 =m$ by volcanic eruption1 l ! simil> objects ) :i* we are acqua9t$ on our own ,e>?1 b t ! o!rs1 despite _! great] sizes1 _h a l orig94 ,9 consequ5ce ( ! feebl] =ce ( gravity on ! ,moon1 ! same explosive =ce !re w\ld c>ry ! mat]ial ( an eruption mu* fur!r ?an on ! ,e>?4 ,! d>k]1 l[-ly+ di/ricts ( ! ,moon give tok5 ( *anges ( a diff]5t ord]4 ,x is manife/ t ! mat]ial ( :i* ! floors ( ^! pla9s is compos$ has invad$1 brok5 d[n1 & almo/ subm]g$ _m ( ! r+-=mations4 ,sometimes half #fa ( a r+ has be5 wa%$ away2 sometimes j ! outl9e ( a r+ c /ill be trac$ ^u ! floor ( ! sea2 sometimes only a slight brea* has be5 made 9 ! wall4 ,s x is cle> t ! ,moon 0 once ri*] 9 ! great crat]-l =mations ?an x is to-day1 b a lava-flood has ov]fl[$ at lea/ "o-?ird ( its area4 ,m rec5t /ill are ! bright /reaks1 or rays1 :i* radiate 9 all directions f ,ty*o1 & f "s ( ! o!r r+-pla9s4 ,x is evid5t f ^! diff]5t types ( /ructure on ! ,moon1 & f ! relations :i* !y be> to ea* o!r1 t ! lun> surface has pass$ ?r\gh sev]al successive /ages1 & t its *anges t5d$1 on ! :ole1 to dim9i% 9 viol5ce z "t w5t on2 ! m9ute crat] pits ) :i* ! surface is /ippl$ hav+ be5 probably ! la/ to =m4 ,b ! #cjj ye>s dur+ :i* ! ,moon has be5 wat*$ ) ! telescope h af=d$ no trace ( any cont9uance ( ^! *anges4 ,%e has _h a /ormy & fi]y pa/2 b no?+ l ! ev5ts ( ^? bygone ages di/urbs h] s]5ity to-day4 ,& yet we mu/ believe t *ange does take place on ! ,moon ev5 n[1 because dur+ ! #ced h\rs ( its long day ! ,sun beats d[n ) full =ce on ! unprotect$ surface1 & dur+ ! equally long night t surface is expos$ to ! cold ( out] space4 ,e "p ( ! surface mu/ be expos$ 9 turn to an extreme range ( temp]ature1 & mu/ be crack$1 torn1 & riv5 by alt]nate expansion & contraction4 ,ap>t f ?is sl[1 we>+ process1 & a v few r d\btful cases 9 :i* a m9ute alt]ation ( "s surface detail has be5 suspect$1 our si/] planet1 ! ,moon1 %[s h]self z *angeless & in]t1 )\t any appreciable trace ( air or wat] or any sign #fb ( life--a dead _w1 ) all its *anges & activities 9 ! pa/4 ,,m>s1 aft] ! ,moon1 is ! planet ^: surface we c /udy to be/ advantage4 ,its orbit lies outside t ( ! ,e>?1 s t :5 x is ne>e/ to u x turns ! same side to bo? ! ,sun & ,e>?1 & we see x fully illum9at$4 ,m]cury & ,v5us1 on ! contr>y1 :5 ne>e/ u are betwe5 u & ! ,sun1 & turn _! d>k sides to u4 ,:5 fully illum9at$ !y are at _! greate/ di/ance1 & appe> v small1 &1 be+ ne> ! ,sun1 are obs]v$ ) difficulty4 ,^! ?ree are int]m$iate 9 size betwe5 ! ,moon & ! ,e>?4 ,9 e>ly telescopic days x 0 se5 t ,m>s 0 an orange-col\r$ globe ) c]ta9 dusky m>k+s ^u x1 & t ^! m>k+s sl[ly *ang$ _! place--t1 9 %ort1 x 0 a _w rotat+ ^u its axis1 & 9 a p]iod n v diff]5t f t ( ! ,e>?4 ,! rotation p]iod ( ,m>s has inde$ be5 fix$ to ! "o-hundr$? "p ( a second ( "t2 x is #bd h4 #cg m4 #bb4fg s4 ,& ?is has be5 possible because "s ( ! dusky spots obs]v$ 9 ! sev5te5? c5tury c be id5tifi$ n[ 9 ! tw5tie?4 ,"s ( ! m>k+s on ,m>s1 l our own cont95ts & seas1 & l ! crat]s on ! ,moon1 are p]man5t features2 & _m *>ts ( ! planet h be5 con/ruct$4 ,o!r m>k+s are v>iable4 ,s9ce ! planet rotates on its axis1 ! positions ( its poles & equator are kn[n1 its equator be+ incl9$ to its orbit at an angle ( #bd #ej'1 :ile ! angle 9 ! case ( ! ,e>? is #bc #bg'4 ,! times :5 its seasons beg9 & end are !re=e kn[n2 & x is f\nd t ! spr+ ( its nor!rn hemisph]e la/s #aii ( our #fc days1 ! summ] #ahc1 ! autumn #adg1 & ! w9t] #aeh4 ,r\nd ! pole 9 w9t] a broad :ite cap =ms1 :i* beg9s to %r9k z spr+ comes on1 & may entirely disappe> 9 summ]4 ,no correspond+ *anges h be5 obs]v$ on ! ,moon1 b x is easy to f9d an analogy to !m on ! ,e>?4 ,r\nd bo? our poles a great cap ( ice & sn[ is spread--a cap :i* increases 9 size z w9t] comes on1 & dim9i%es ) ! advance ( summ]--& x seems a reasonable inf]5ce to suppose t ! :ite pol> caps ( ,m>s are1 l our own1 compos$ ( ice & sn[4 ,f "t to "t indications h be5 obs]v$ ( ! pres5ce on ,m>s ( a c]ta9 am\nt ( cl\d4 ,famili> d>k m>k+s h1 = a %ort "t1 be5 int]rupt$1 or be5 entirely hidd51 by :ite b&s1 & h recov]$ _! ord9>y appe>ance lat]4 ,) rotation on its axis & succession ( seasons1 ) atmosph]e & cl\d1 ) l& & wat]1 ) ice & sn[1 ,m>s w\ld seem to be a _w v simil> to our own4 ,?is 0 ! g5]al op9ion up to ! ye> #ahgg1 :5 ,,s*iap>elli ann\nc$ t he _h discov]$ a numb] ( v n>r[1 /raight1 d>k l9es on ! planet--l9es to :i* he gave ! "n ( canali--t is1 *annels4 ,?is ^w 0 un=tunately r5d]$ into ,engli% by ! ^w canals1 &1 z a canal means a wat]way artificially made1 ?is mi/ranslation gave ! idea t ,m>s 0 inhabit$ by intellig5t be+s1 :o _h dug out ! surface ( ! planet into a network ( canals ( /up5d\s l5g? & bread?4 ,! *ief advocate ( ?is !ory is ,,l[ell1 an ,am]ican obs]v]1 :o has giv5 v great att5tion #fd to ! /udy ( ! planet dur+ ! la/ sev5te5 ye>s4 ,8 argum5t is t ! /raight l9es1 ! canals1 :i* he sees on ! planet1 & ! r\nd dots1 ! oases1 :i* he f9ds at _! int]sections1 =m a sy/em s obvi\sly unnatural1 t x mu/ be ! "w ( design--( intellig5t be+s4 ,! canals are to him absolutely regul> & /raight1 l l9es drawn ) rul] & p5-&-ink1 & ! oases are exactly r\nd4 ,b1 on ! "o h&1 ! be/ obs]v]s1 arm$ ) ! mo/ p[]ful telescopes1 h (t5 be5 able to p]ceive t m>k+s 7 really full ( irregul> detail1 :i* ,l[ell has repres5t$ z m]e h>d /raight l9es & circul> dots1 &1 on ! o!r h&1 ! /raight l9e & ! r\nd dot are ! two geometric =ms :i* all v m9ute objects mu/ approa* 9 appe>ance4 ,t we _c see irregul>ities 9 v small & di/ant objects is no pro( at all t irregul>ities d n exi/ 9 !m1 & x has (t5 happ5$ t a m>k+ :i* appe>$ a typical canal :5 ,m>s 0 at a great di/ance lo/ t appe>ance :5 ! planet 0 ne>]4 ,a/ronom]s1 !re=e1 are almo/ unanim\s t !re is no reason = suppos+ t any ( ! details t we see on ! surface ( ,m>s are artificial 9 _! orig94 ,& inde$ ! num]ical facts t we "k ab\t ! planet r5d] x almo/ impossible t !re %\ld be any life ^u x4 ,if we turn to ! table1 we see t 9 size1 volume1 d5sity1 & =ce ( gravity at its surface1 ,m>s lies betwe5 ! ,moon & ! ,e>?1 b is ne>] ! ,moon4 ,?is has an important be>+ z to ! "q ( ! planet's atmosph]e4 ,on ! ,e>? we pass ?r\gh half ! atmosph]e by asc5d+ a m\nta9 #fe t is ?ree & a ?ird miles 9 height2 on ,m>s we %\ld h to asc5d ne>ly n9e miles4 ,if ! atmosph]ic pressure at ! surface ( ,m>s 7 z great z x is at ! surface ( ! ,e>?1 8 atmosph]e w\ld be f> deep] ?an ours & w\ld veil ! planet m effectively4 ,b we see ! surface ( ,m>s ) rem>kable di/9ctness1 almo/ z cle>ly1 :5 its great] di/ance is all[$ =1 z we see ! ,moon4 ,x is !re=e accept$ t ! atmosph]ic pressure at ! surface ( ,m>s mu/ be v slight1 probably mu* less ?an at ! top ( our v highe/ m\nta9s1 :]e !re is et]nal sn[1 & life is completely abs5t4 ,b ,m>s comp>es badly ) ! ,e>? 9 ano!r respect4 ,x receives less light & heat f ! ,sun 9 ! proportion ( ?ree to sev54 ,?is we may express by say+ t ,m>s1 on ! :ole1 is almo/ z mu* worse (f ?an ! ,e>? z a po9t on ! ,arctic ,circle is worse (f ?an a po9t on ! ,equator4 ,! mean temp]ature ( ! ,e>? is tak5 z ab\t #fj ( ! ,fahr5heit !rmomet] 7say1 #ae ,c5t472 ! mean temp]ature ( ,m>s mu/ c]ta9ly be consid]ably bel[ freez+-po9t1 probably ne> #j ,f4 ,"h on our ,e>? ! boil+-po9t ( wat] is #bab1 &1 s9ce ! mean temp]ature is #fj & wat] freezes at #cb1 x is normally 9 ! liquid /ate4 ,on ,m>s x mu/ normally be 9 ! solid /ate--ice1 sn[1 or fro/1 or ! l4 ,b ) s r>e an atmosph]e wat] w boil at a l[ temp]ature1 & x is n impossible t "u ! direct rays ( ! ,sun--t is to say1 at midday ( ! torrid zone ( ,m>s--ice may n only melt1 b wat] boil by day1 cond5s+ & freez+ aga9 dur+ ! night4 ,,newcomb1 ! =emo/ a/ronom] ( 8 day1 conclud$ t dur+ #ff ! night ( ,m>s1 ev5 9 ! equatorial regions1 ! surface ( ! planet probably falls to a l[] temp]ature ?an any we ev] exp]i5c$ on our globe4 ,if any wat] exi/s1 x mu/ n only be froz51 b ! temp]ature ( ! ice mu/ be f> bel[ ! freez+ po9t4444 ,! mo/ c>eful calculation %[s t if !re are any consid]able bodies ( wat] on our neighb\r+ planet1 !y exi/ 9 ! =m ( ice1 & c nev] be liquid to a dep? ( m ?an "o or two in*es1 & t only )9 ! torrid zone & dur+ a few h\rs ea* day4 ,) reg>d to ! sn[ caps ( ,m>s1 ,newcomb ?\ght x n possible t any consid]able fall ( sn[ c\ld ev] take place4 ,he reg>d$ ! :ite caps z simply due to a ?9 deposit ( ho> fro/1 & x _c be deem$ wond]ful t su* %\ld gradually disappe>1 :5 x is rememb]$ t ea* ( ! two poles ( ,m>s is 9 turn pres5t$ to ! ,sun = m ?an #cjj consecutive days4 ,newcomb's conclusion 03 ,?us we h a k9d ( ,m>tian meteorological *anges1 v slight inde$1 & seem+ly v diff]5t f ^? ( our ,e>?1 b yet foll[+ simil> l9es on _! small scale4 ,= sn[fall sub/itute fro/fall2 in/ead ( 7! b>omet] read+7 feet or in*es say fractions ( a millimetre1 & in/ead ( /orms or w9d sub/itute little motions ( an air ?9n] ?an t on ! top ( ! ,himalayas1 & we %all h a g5]al description ( ,m>tian meteorology4 ,we conclude1 !n1 t ,m>s is n s in]t a _w z ! ,moon1 b1 ?\gh "s slight *anges ( climate or wea!r take place ^u x1 x is q unfitt$ = ! n\ri%m5t & developm5t ( ! diff]5t =ms ( organic life4 ,( ,,m]cury we "k v little4 ,x is small] ?an ,m>s b l>g] ?an ! ,moon1 b x diff]s f !m #fg bo? 9 t x is mu* ne>] ! ,sun1 & receives1 !re=e1 _m times ! light & heat1 surface = surface4 ,we %\ld expect1 !re=e1 t wat] on ,m]cury w\ld exi/ 9 ! gase\s /ate in/ead ( 9 ! solid /ate z on ,m>s4 ,! little planet reflects ! sunlight only feebly1 & %[s no evid5ce ( cl\d4 ,a few m>k+s h be5 made out on its surface1 & ! be/ obs]v]s agree t x appe>s to turn ! same face always to ! ,sun4 ,?is w\ld imply t ! "o hemisph]e is 9 p]petual d>kness & cold1 ! o!r1 expos$ to an unimag9able fi]y heat4 ,,v5us is ne>ly ( ! same size z ! ,e>?1 & ! conditions z to ! arrangem5t ( its atmosph]e1 ! =ce ( gravity at its surface1 mu/ be ne>ly ! same z on our own _w4 ,b we "k almo/ no?+ ( ! details ( its surface2 ! planet is v bright1 reflect+ fully sev5-t5?s ( ! sunlight t falls ^u x4 ,x w\ld seem t1 9 g5]al1 we see no?+ ( ! actual details ( ! planet1 b only ! upp] surface ( a v cl\dy atmosph]e4 ,ow+ to ! fact t ,v5us %[s no fix$ def9ite m>k+ t we c wat*1 x is /ill a matt] ( controv]sy z to ! "t 9 :i* x rotates ^u its axis4 ,s*iap>elli & "s o!r obs]v]s consid] t x rotates 9 ! same "t z x revolves r\nd ! ,sun4 ,o!rs believe t x rotates 9 a little less ?an tw5ty-f\r h\rs4 ,if ?is be s1 & !re is any body 9 ! sol> sy/em o!r ?an ! ,e>?1 :i* is adapt$ to be ! home ( life1 !n ! planet ,v5us is t "o4 ,,! ,,sun1 l ! ,moon1 pres5ts a visible surface to ! nak$ eye1 b "o t %[s no details4 ,9 ! telescope ! contra/ betwe5 x & ! ,moon is v great1 & /ill great] is ! contra/ :i* is br\ght #fh out by ! measurem5ts ( its size1 volume1 & weight4 ,b ! really significant diff]5ce is t ! ,sun is a body giv+ out light & heat1 n m]ely reflect+ !m4 ,)\t d\bt ?is la/ diff]5ce is connect$ mo/ closely ) ! diff]5ce 9 size4 ,! ,moon is cold1 dead1 un*ang+1 because x is a small _w2 ! ,sun is bright1 f]v5t1 & und]goes ! mo/ viol5t *ange1 because x is an exce$+ly l>ge _w4 ,! two bodies--! ,sun & ,moon--appe> to ! eye z be+ ab\t ! same size1 b s9ce ! ,sun is #djj times z f> (f z ! ,moon x mu/ be #djj times ! diamet]4 ,t means t x has #djj times #djj1 or #afj1jjj times ! surface & #djj times #djj times #djj1 or #fd1jjj1jjj times ! volume4 ,! ,sun & ,moon1 !re=e1 /& at ! v extremes ( ! scale4 ,! heat ( ! ,sun is s great t !re is "s difficulty 9 obs]v+ x 9 ! telescope4 ,x is n suffici5t to use a d>k glass 9 ord] to protect ! eye1 unless ! telescope be q a small "o4 ,"s means h to be employ$ to get rid ( ! great] "p ( ! heat & light4 ,! simple/ me?od ( obs]v+ is to fix a scre5 beh9d ! eyepiece ( a telescope & let ! image ( ! ,sun be project$ ^u ! scre51 or ! s5sitive plate may be sub/itut$ = ! scre51 & a photograph obta9$1 :i* c be exam9$ at leisure aft]w>ds4 ,z g5]ally se51 ! surface ( ! ,sun appe>s to be mottl$ all ov] by a f9e irregul> /ippl+4 ,?is /ippl+1 ?\gh ev]y:]e pres5t1 is n v /rongly m>k$1 & a fir/ ha/y glance might ov]look x4 ,f "t to "t1 h[ev]1 d>k spots are se51 ( ev]-*ang+ =m & size4 ,by wat*+ ^!1 ,galileo prov$ t ! ,sun rotat$ on its axis 9 a little m ?an tw5ty-five days1 & 9 ! #fi n9ete5? c5tury ,,s*wabe prov$ t ! sunspots 7 n equally l>ge & num]\s at all times1 b t !re 0 a k9d ( cycle ( a little m ?an elev5 ye>s 9 av]age l5g?4 ,at "o "t ! ,sun w\ld be free f spots2 !n a few small ones w\ld appe>2 ^! w\ld gradually become l>g] & m num]\s2 !n a decl9e w\ld foll[1 & ano!r spotless p]iod w\ld succe$ ab\t elev5 ye>s aft] ! fir/4 ,z a rule1 ! increase 9 ! spots takes place m quickly ?an ! decl9e4 ,mo/ ( ! spot-gr\ps la/ only a v few days1 b ab\t "o gr\p 9 f\r la/s long en\gh to be br\ght r\nd by ! rotation ( ! ,sun a second "t2 9 o!r words1 x cont9ues = ab\t a mon?4 ,9 a v few cases spots h endur$ = half a ye>4 ,an ord9>y =m = a gr\p ( spots is a long /ream drawn out p>allel to ! ,sun's equator1 ! lead+ spot be+ ! l>ge/ & be/ def9$4 ,x is foll[$ by a numb] ( v small irregul> & ill-develop$ spots1 & ! tra9 is br\ght up by a l>ge spot1 sometimes ev5 l>g] ?an ! lead]1 b by no means s regul> 9 =m or s well def9$4 ,! lead+ spot = a %ort "t moves =w>d mu* fa/] ?an its foll[]s1 at a spe$ ( ab\t #hjjj miles p] day4 ,! small middle spots !n gradually die out1 or r seem to be ov]fl[$ by ! bright mat]ial ( ! sol> surface1 ! photosph]e1 z x is call$2 ! spot 9 ! re> breaks up a little lat]1 & ! lead]1 :i* is n[ almo/ circul>1 is left alone1 & may la/ 9 ?is condition = "s weeks4 ,f9ally1 x sl[ly contracts or breaks up1 & ! di/urbance comes to an end4 ,?is is ! c\rse ( developm5t ( _m long-liv$ spot-gr\ps1 b all d n con=m to ! same type4 #gj ,! v l>ge/ spots are inde$ usually q diff]5t 9 _! appe>ance & hi/ory4 ,9 size1 sunspots v>y f ! smalle/ dot t c be discov]$ 9 ! telescope up to huge r5ts ) areas t are to be c\nt$ by ?\s&s ( millions ( squ>e miles2 ! great gr\p ( ,febru>y #aije _h an area ( #d1jjj1jjj1jjj squ>e miles1 a ?\s& times ! area ( ,europe4 ,closely associat$ ) ! macul1 z ! spots 7 call$ by ! fir/ obs]v]s1 are ! facul--long1 bran*+ l9es ( bright :ite light1 bright z se5 ev5 aga9/ ! dazzl+ backgr\nd ( ! ,sun itself1 & look+ l ! long l9es ( foam ( an incom+ tide4 ,^! are (t5 associat$ ) ! spots2 ! spots are =m$ betwe5 _! ridges1 & aft] a spot-gr\p has disappe>$ ! brok5 waves ( facul w sometimes p]si/ 9 ! same region = q a long "t4 ,! facul cle>ly rise above ! ord9>y sol> surface2 ! spots z cle>ly are depress$ a little bel[ x2 because f "t to "t we see ! bright mat]ial ( ! surface p\r ov] spots1 across !m1 & sometimes into !m4 ,b !re is no reason to believe t ! spots are deep1 9 proportion ei!r to ! ,sun itself or ev5 to _! own ext5t4 ,sunspots are n se5 9 all regions ( ! ,sun4 ,x is v seldom t !y are not$ 9 a high] sol> latitude ?an #dj1 ! great majority ( spots ly+ 9 ! two zones betwe5 #e & #be latitude on ei!r side ( ! equator4 ,facul1 on ! o!r h&1 ?\gh mo/ frequ5t 9 ! spot zones1 are obs]v$ mu* ne>] ! two poles4 ,x is v h>d to f9d analogies on our ,e>? = sunspots & = _! peculi>ities ( behavi\r4 ,"s #ga ( ! e>li] a/ronom]s ?\ght !y 7 l t]re/rial volcanoes1 or r l ! eruptions f !m4 ,b if !re 7 a solid nucleus to ! ,sun1 & ! spots 7 eruptions f def9ite areas ( ! nucleus1 !y w\ld all give ! same p]iod ( rotation4 ,b sunspots move ab\t freely on ! sol> surface1 & ! diff]5t zones ( t surface rotate 9 diff]5t times1 ! region ( ! equator rotat+ ! mo/ quickly4 ,?is alone is en\gh to %[ t ! ,sun is ess5tially n a solid body4 ,yet f> d[n bel[ ! photosph]e some?+ approa*+ to a def9ite /ructure mu/ already be =m+4 ,= !re is a well-m>k$ progression 9 ! zones ( sunspots dur+ ! elev5-ye> cycle4 ,at a "t :5 spots are few & small1 kn[n z ! sunspot m9imum1 !y beg9 to be se5 9 fairly high latitudes4 ,z !y get m num]\s1 & _m ( !m l>g]1 !y frequ5t ! m$ium zones4 ,:5 ! ,sun is at its greate/ activity1 kn[n z ! sunspot maximum1 !y are f\nd f ! highe/ zone "r d[n to ! equator4 ,!n ! decl9e sets 91 b x sets 9 fir/ 9 ! highe/ zones1 & :5 ! "t ( m9imum has come aga9 ! spots are close to ! equator4 ,be=e ^! h all di$ away1 a few small spots1 ! h]alds ( a new cycle ( activity1 beg9 to appe> 9 high latitudes4 ,?is law1 call$ aft] ,,sp,,r]1 its discov]]1 indicates t ! orig9 & s\rce ( sunspot activity lie )9 ! ,sun4 ,at "o "t x 0 ?\ght t sunspots 7 due to "s action ( ,jupit]--= ,jupit] moves r\nd ! ,sun 9 #aa4h ye>s1 a p]iod n v diff]5t f ! sunspot cycle--or to "s meteoric /ream4 ,b ,spr]'s ,law c\ld n be impos$ by "s influ5ce f )\t4 ,/ill sunspots1 once =m$1 may be influ5c$ by ! ,e>?1 & p]haps by o!r #gb planets also1 = ,,mrs4 ,,walt] ,,maund] has %[n t ! numb]s & areas ( spots t5d to be small] on ! we/]n half ( ! disc1 z se5 f ! ,e>?1 ?an on ! ea/]n1 :ile consid]ably m gr\ps come into view at ! ea/ edge ( ! ,sun ?an pass out ( view at ! we/ edge1 s t x w\ld appe> z if ! ,e>? _h a damp+ effect ^u ! spots expos$ to x4 ,b ! ,sun is f> great] ?an x ord9>ily appe>s to u4 ,twice e ye>1 & sometimes (t5]1 ! ,moon1 :5 new1 comes betwe5 ! ,e>? & ! ,sun1 & we h an ,eclipse ( ! ,sun1 ! d>k body ( ! ,moon hid+ "p1 or all1 ( ! great] light4 ,! ,sun & ,moon are s ne>ly ( ! same app>5t size t an eclipse ( ! ,sun is total only = a v n>r[ belt ( ! ,e>?'s surface1 &1 z ! ,moon moves m quickly ?an ! ,sun1 ! eclipse only rema9s total = a v %ort "t--sev5 m9utes at ! outside1 m usually only two or ?ree4 ,nor? or s\? ( t belt ! ,moon is project$1 s z to leave uncov]$ a "p ( ! ,sun nor? or s\? ( ! ,moon4 ,a total eclipse1 !re=e1 is r>e at any p>ticul> place1 & if a man 7 able to put himself 9 ! be/ possible position on ea* occasion1 x w\ld co/ him ?irty ye>s to secure an h\r's accumulat$ duration4 ,eclipses ( ! ,moon are visible ov] half ! _w at "o "t1 = !re is a real loss to ! ,moon ( h] light4 ,h] eclipses are br\ght ab\t :51 9 h] orbit1 %e passes beh9d ! ,e>?1 & ! ,e>?1 be+ betwe5 ! ,sun & ! ,moon1 cuts (f f ! latt] mo/ ( ! light fall+ ^u h]2 n q all2 a small portion rea*es h] aft] pass+ ?r\gh ! ?icke/ "p ( ! ,e>?'s atmosph]e1 s t ! #gc ,moon 9 an eclipse looks a deep copp] col\r1 mu* z %e does :5 ris+ on a foggy ev5+4 ,total eclipses ( ! ,sun h well repaid all ! ef=ts made to obs]ve !m4 ,x is a wond]ful sight to wat* ! blackness ( d>kness sl[ly creep+ ov] ! v f\nta9 ( light until x is :olly & entirely hidd52 to wat* ! col\rs fade away f ! l&scape & a dea?like1 lead5 hue p]vade all nature1 & !n to see a silv]y1 />-l halo1 fleck$ ) bright little rose-col\r$ flames1 fla% out r\nd ! black disc t has tak5 ! place ( ! ,sun4 ,^! rose-col\r$ flames are ! sol> prom95ces1 & ! halo is ! corona1 & x is to wat* ^! t a/ronom]s h made s _m exp$itions hi!r & ?i!r dur+ ! la/ sev5ty ye>s4 ,! prom95ces1 or r$ flames1 c be obs]v$1 )\t an eclipse1 by means ( ! spectroscope1 b1 z ! "w ( ! spectroscope is to =m ! subject ( ano!r volume ( ?is s]ies1 x is suffici5t to add "h t ! prom95ces are compos$ ( v>i\s gl[+ gases1 *iefly ( hydrog51 calcium1 & helium4 ,^! & o!r gases =m a %ell r\nd ! ,sun1 ab\t #cjjj miles 9 dep?1 to :i* ! "n *romosph]e has be5 giv54 ,x is out ( ! *romosph]e t ! prom95ces arise z va/ irregul> jets & cl\ds4 ,ord9>ily !y d n exce$ #dj or #ej ?\s& miles 9 height1 b occasionally !y ext5d = #bjj or ev5 #cjj ?\s& miles f ! ,sun4 ,_! *anges are z rem>kable z _! dim5sions2 huge jets ( #ej or #ajj ?\s& miles h be5 se5 to =m1 rise1 & disappe> )9 an h\r or less1 & movem5ts h be5 *ronicl$ ( #bjj or #cjj miles 9 a s+le second ( "t4 ,prom95ces are l>ge/ & mo/ frequ5t :5 #gd sunspots & facul are mo/ frequ5t1 & fewe/ :5 ^? are fewe/4 ,! corona1 too1 v>ies ) ! sunspots4 ,at ! "t ( maximum ! corona s5ds =? rays & /ream]s 9 all directions1 & looks l ! conv5tional figure ( a /> on a gigantic scale4 ,at m9imum ! corona is simpl] 9 =m1 & %[s two great w+s1 ea/ & we/1 9 ! direction ( ! ,sun's equator1 & r\nd bo? ( 8 poles a numb] ( small1 beautiful jets l a cre/ ( fea!rs4 ,"s ( ! /ream]s or w+s ( ! corona h be5 trac$ to an enorm\s di/ance f ! ,sun4 ,mrs4 ,walt] ,maund] photograph$ "o ray ( ! corona ( #ahih to a di/ance ( #f millions ( miles4 ,,langley1 9 ! cle> air ( ,pike's ,peak1 trac$ ! w+s ( ! corona ( #ahgh ) ! nak$ eye to ne>ly d\ble ?is di/ance4 ,b ! rapid *anges ( sunspots & ! viol5ce ( "s ( ! prom95ce eruptions are b feeble indications ( ! mo/ wond]ful fact conc]n+ ! ,sun1 i4e4 ! enorm\s am\nt ( light & heat :i* x is cont9ually giv+ (f4 ,"h we c only put toge!r figures :i* by _! va/ness escape our und]/&+4 ,sunlight is to moonlight z #fjj1jjj is to #a1 s t if ! entire sky 7 fill$ up ) full moons1 !y w\ld n give u a qu>t] z mu* light z we d]ive f ! ,sun4 ,! int5sity ( sunlight exce$s by f> any artificial light2 x is #aej times z bright z ! calcium light1 & ?ree or f\r times z bright z ! brighte/ "p ( ! electric arc light4 ,! am\nt ( heat radiat$ by ! ,sun has be5 express$ 9 a v>iety ( diff]5t ways2 ,c4 ,a4 ,,"y v graphically by say+ t if ! ,sun 7 encas$ 9 a %ell ( ice #fd feet deep1 its heat w\ld melt ! %ell 9 "o m9ute1 & t if a bridge ( ice c\ld be #ge =m$ f ! ,e>? to ! ,sun1 #b- miles squ>e 9 section & #ic millions ( miles long1 & ! entire sol> radiation conc5trat$ ^u x1 9 "o second ! ice w\ld be melt$1 9 sev5 m dissipat$ into vap\r4 ,! ,e>? d]ives f ! ,sun n m]ely light & heat1 b1 by trans=mation ( ^!1 almo/ e =m ( en]gy manife/ ^u x2 ! en]gy ( ! gr[? ( plants1 ! vital en]gy ( animals1 are only ! en]gy receiv$ f ! ,sun1 *ang$ 9 its expression4 ,! "q naturally arises1 ,if ! ,sun1 to :i* ! ,e>? is indebt$ = ne>ly ev]y?+1 passes ?r\gh a *ange 9 its activity e elev5 ye>s or s1 h[ is ! ,e>? affect$ by x8 ,x w\ld seem at fir/ sight t ! effect %\ld be great & manife/4 ,a sunspot1 l t ( ,febru>y #aije1 "o ?\s& times z l>ge z ,europe1 into :i* worlds z l>ge z our ,e>? might be p\r$1 l peas into a sauc]1 mu/ mean1 "o might ?9k1 an imm5se fall+ (f ( ! sol> heat4 ,yet x is n s4 ,= ev5 ?is great sunspot 0 b small z comp>$ ) ! ,sun z a :ole4 ,_h x be5 dead black1 x w\ld h /opp$ out mu* less ?an #a p] c5t4 ( ! ,sun's heat2 & ev5 ! d>ke/ sunspot is really v bright4 ,& ! m spots !re are1 ! m num]\s & bright] are ! facul2 s t we d n "k c]ta9ly :i* ( ! two phases1 maximum or m9imum1 means ! great] radiation4 ,if ! wea!r on ! ,e>? answ]s to ! sunspot cycle1 ! connection is n a simple "o2 z yet no connection has be5 prov$4 ,?us two ( ! wor/ & colde/ summ]s exp]i5c$ 9 ,engl& fell ! "o 9 #ahfj1 ! o!r 9 #ahgi1 i4e4 at #gf maximum & m9imum respectively4 ,s1 too1 ! hot summ]s ( #ahic & #aiaa 7 also1 ! "o at maximum & ! o!r at m9imum2 & ord9>y av]age ye>s h fall5 at bo? ! phases j ! same4 ,yet !re is an answ] on ! "p ( ! ,e>? to ^! sol> *anges4 ,! ,e>? itself is a k9d ( magnet1 possess+ a magnetism ( :i* ! int5sity & direction is always *ang+4 ,to wat* ^! *anges1 v s5sitive magnets are set up1 & a slight daily to-&-fro sw+ is notic$ 9 !m2 ?is sw+ is m m>k$ 9 summ] ?an 9 w9t]1 b x is also m m>k$ at times ( ! sunspot maximum ?an at m9imum1 %[+ a dep5d5ce ^u ! sol> activity4 ,yet m1 f "t to "t ! magnetic ne$le und]goes m or less viol5t di/urbance2 9 extreme cases ! electric telegraph communication has be5 di/urb$ all ov] ! _w1 z on ,septemb] #be1 #aiji1 :5 ! subm>9e cables ceas$ to c>ry messages = sev]al h\rs4 ,9 mo/ cases :5 su* a magnetic /orm occurs1 !re is an unusually l>ge or active spot on ! ,sun4 ,! writ] 0 able 9 #aijd to fur!r prove t su* /orms h a m>k$ t5d5cy to recur :5 ! same longitude ( ! ,sun is pres5t$ aga9 t[>ds ! ,e>?4 ,?us 9 ,febru>y #ahib1 :5 a v l>ge spot 0 on ! ,sun1 a viol5t magnetic /orm broke out4 ,! spot pass$ out ( sight & ! /orm ceas$1 b 9 ! foll[+ mon?1 :5 ! spot rea*$ exactly ! same app>5t place on ! ,sun's disc1 ! /orm broke out aga94 ,su* magnetic di/urbances are !re=e due to /reams ( p>ticles driv5 (f f limit$ areas ( ! ,sun1 probably 9 ! same way t ! long1 #gg /raight rays ( ! corona are driv5 (f4 ,su* /reams ( p>ticles1 %ot out into space1 d n spread out equally 9 all directions1 l ! rays ( light & heat1 b are limit$ 9 direction1 & f "t to "t !y ov]take ! ,e>? 9 its orbit1 &1 /rik+ x1 cause a magnetic /orm1 :i* is felt all ov] ! ,e>? at practically ! same mom5t4 ,,jupit] is1 aft] ! ,sun1 mu* ! l>ge/ memb] ( ! sol> sy/em1 & x is a peculi>ly beautiful object 9 ! telescope4 ,ev5 a small in/rum5t %[s ! little disc /rip$ ) _m delicately col\r$ b&s or belts1 brok5 by :ite cl\ds & d>k /reaks1 l a w9dy sky at sunset4 ,& x *anges :ile be+ wat*$1 =1 ?\gh #djj1jjj1jjj miles away f u1 x rotates s fa/ ^u its axis t its c5tral m>k+s c actually be se5 to move4 ,?is rapid rotation1 9 less ?an t5 h\rs1 is ! mo/ significant fact ab\t ,jupit]4 ,= diff]5t spots h diff]5t rotation p]iods1 ev5 9 ! same latitude1 prov+ t we are look+ d[n n ^u any solid surface ( ,jupit]1 b ^u its cl\d envelope--an envelope swept by its rapid rotation & by its w9ds into a va/ sy/em ( p>allel curr5ts4 ,"o object on ,jupit]1 ! great ,r$ ,spot1 has be5 "u obs]vation s9ce #ahgh1 & possibly = #bjj ye>s be=e t4 ,x is a l>ge1 oval object fitt$ 9 a frame ( ! same %ape4 ,! spot itself has (t5 fad$ & be5 lo/ s9ce #ahgh1 b ! frame has rema9$4 ,! spot is 9 size & position relative to ,jupit] mu* z ,au/ralia is to ! ,e>?1 b :ile ,au/ralia moves solidly ) ! re/ ( ! ,e>? 9 ! daily rotation1 nei!r ga9+ on ,s\? ,am]ica nor los+ on ,africa1 ! ,r$ ,spot on ,jupit] sees _m o!r spots & cl\ds pass x by1 & does n ev5 #gh reta9 ! same rate ( motion itself f "o ye> to ano!r4 ,no o!r m>k+ on ,jupit] is s p]man5t z ?is4 ,f "t to "t great r\nd :ite cl\ds =m 9 a long s]ies z if %ot up f "s eruption bel[1 & !n drawn into ! equatorial curr5t4 ,f "t to "t ! belts !mselves *ange 9 bread?1 9 col\r1 & complexity4 ,jupit] is emphatically ! planet ( *ange4 ,& su* *ange means en]gy1 especially en]gy 9 ! =m ( heat4 ,if ,jupit] possess$ no heat b t x d]iv$ f ! ,sun1 x w\ld be cold] ?an ,m>s1 & !re=e an absolutely froz5 globe4 ,b ^! ru%+ w9ds & hurry+ cl\ds are evid5ces ( heat & activity--a native heat mu* above t ( our ,e>?4 ,:ile ,m>s is probably ne>] to ! ,moon ?an to ! ,e>? 9 its condition1 ,jupit] has probably m analogies ) ! ,sun4 ,! "o unrivall$ di/9ction ( ,,saturn is its ,r+4 ,no?+ l ?is exi/s else:]e 9 ! sol> sy/em4 ,ev]y:]e else we see sph]ical globes2 ?is is a flat disc1 b )\t its c5tral portion4 ,x surr\nds ! planet1 ly+ 9 ! plane ( its equator1 b t\*es x n[h]e1 a gap ( #gjjj miles int]v5+4 ,x appe>s to be circul>1 & is #db1jjj miles 9 bread?4 ,yet x is n1 z x appe>s to be1 a flat cont9u\s surface4 ,x is 9 reality made up ( an inf9ite numb] ( t9y satellites1 m]e du/ or pebbles = ! mo/ "p1 b s num]\s z to look f our di/ance l a cont9u\s r+1 or r l ?ree or f\r conc5tric r+s1 = c]ta9 divisions h be5 notic$ 9 x--an inn] broad division call$ aft] its discov]]1 ,,cass9i1 & an out]1 fa9t]1 n>r[] "o discov]$ by ,,encke4 ,! inn]mo/ "p ( ! r+ is dusky1 fa9t] #gi ?an ! planet or ! re/ ( ! r+1 & is kn[n z ! crape-r+4 ,( ,saturn itself we "k little2 x is fur!r (f & fa9t] ?an ,jupit]1 & its details are n s pron\nc$1 b 9 g5]al !y resemble ^? ( ,jupit]4 ,! planet rotates quickly--9 #aj h4 #ad m4--its m>k+s run into p>allel belts1 & are div]sifi$ by spots ( ! same "* z on ,jupit]4 ,saturn is probably possess$ ( no small am\nt ( native heat4 ,,uranus & ,,neptune are mu* small] bodies ?an ,jupit] & ,saturn1 ?\gh f> l>g] ?an ! ,e>?4 ,b _! di/ance f ! ,e>? & ,sun makes _! discs small & fa9t1 & !y %[ little 9 ! telescope beyond a h9t ( belts l ^? ( ,jupit]2 s t1 z ) t planet1 ! surfaces t !y %[ are almo/ c]ta9ly ! upp] surfaces ( a %ell ( cl\d4 ,9 g5]al1 !re=e1 ! rule appe>s to hold good ?r\gh\t ! sol> sy/em t a v l>ge body is int5sely hot & 9 a condition ( viol5t activity & rapid *ange2 t small] bodies are less hot & less active1 until we come d[n to ! smalle/1 :i* are cold1 in]t1 & dead4 ,our own ,e>?1 midway 9 ! s]ies1 is itself cold1 b is plac$ at su* a di/ance f ! ,sun z to receive f x a suffici5t b n excessive supply ( light & heat1 & ! *anges ( ! ,e>? are su* z n to prohibit b to n\ri% & support ! gr[? & developm5t ( ! v>i\s =ms ( life4 ,! smalle/ memb]s ( ! sol> sy/em are kn[n z ,,meteors4 ,^! are (t5 no m ?an pebbles or p>ticles ( du/1 mov+ toge!r 9 associat$ orbits r\nd ! ,sun4 ,!y are too small & too scatt]$ to be se5 9 op5 space1 & become visible to u only #hj :5 _! orbits int]sect t ( ! e>?1 & ! e>? actually enc\nt]s !m4 ,!y !n ru% into our atmosph]e at a great spe$1 & become highly heat$ & lum9\s z !y compress ! air be=e !m2 s highly heat$ t mo/ are vap\ris$ & dissipat$1 b a few rea* ! gr\nd4 ,z !y are actually mov+ 9 p>allel pa?s at ! "t ( "o ( ^! enc\nt]s1 !y appe> f ! effect ( p]spective to div]ge f a po9t1 h5ce call$ ! radiant4 ,"s %[]s occur on ! same date ( e ye>2 ?us a radiant 9 ! con/ellation ,lyra is active ab\t ,april #ba1 giv+ u meteors1 kn[n z ! ,lyrids2 & ano!r 9 ,p]seus 9 ,augu/1 gives u ! ,p]seids4 ,o!r radiants are active at int]vals ( sev]al ye>s2 ! mo/ fam\s ( all meteoric %[]s1 t ( ! ,leonids1 f a radiant 9 ,leo1 0 active = _m c5turies e ?irty-?ird ye>2 & ano!r fall+ 9 ! same mon?1 ,novemb]1 came f a radiant 9 ,&rom$a e ?irte5 ye>s4 ,9 ^! f\r cases & 9 "s o!rs ! meteors h be5 f\nd to be travell+ along ! same pa? z a comet4 ,x is !re=e consid]$ t meteoric sw>ms are due to ! gradual break up ( comets2 inde$ ! comet ( ! ,&rom$a %[]1 kn[n f "o ( its obs]v]s z ,biela's1 0 actually se5 to divide into two 9 ,decemb] #ahde1 & has n be5 obs]v$ z a comet s9ce #aheb1 ?\gh ! %[]s connect$ ) x1 giv+ u ! meteors kn[n z ! ,&rom$es1 h cont9u$ to be frequ5t & ri*4 ,meteors1 !re=e1 are ! smalle/1 mo/ insignificant1 ( all ! cele/ial bodies2 & ! %9+ out ( a meteor is ! la/ /age ( its hi/ory--its dea?2 aft] dea? x simply goes to add an inf9itesimal trifle to ! du/ ( ! e>?4 #ha ,,*apt] ,,vi ,,! ,,sy/em ,,( ,,! ,,/>s ,! fir/ /ep t[>ds our k ( ! />ry heav5s 0 made :5 ! unkn[n & =gott5 a/ronom]s ( #bgjj ,b4,c4 arrang$ ! />s into con/ellations1 = x 0 ! fir/ /ep t[>ds di/+ui%+ "o /> f ano!r4 ,:5 "o /> began to be kn[n z ! /> 9 ! eye ( ! ,bull1 & ano!r z ! /> 9 ! %\ld] ( ! ,giant1 ! heav5s ceas$ to display an indiscrim9ate cr[d ( tw9kl+ lights2 ea* /> began to possess individuality4 ,! next /ep 0 tak5 :5 ,hipp>*us made 8 catalogue ( />s 7#abi ,b4,c471 n only giv+ its "n to ea* />1 b measur+ & fix+ its place--a catalogue repres5t$ to u by t ( ,claudius ,ptolemy 7,a4,d4 #acg74 ,! ?ird /ep 0 tak5 :5 ,,bradley1 ! ?ird ,a/ronom] ,royal1 made1 at ,gre5wi*1 a catalogue ( m ?an #cjjj />-places det]m9$ ) ! telescope4 ,a c5tury lat] ,,argel&] made ! great ,bonn ,zone catalogue ( #ccj1jjj />s1 & n[ a great photographic catalogue & *>t ( ! entire heav5s h be5 arrang$ betwe5 eighte5 obs]vatories ( diff]5t c\ntries4 ,?is great *>t :5 complete w probably pres5t #cj millions ( />s 9 position & brightness4 #hb ,! "q naturally arises1 ,:y s _m />s8 ,:at conceivable use c be s]v$ by catalogues ( #cj millions or ev5 ( #cjjj />s8 ,& s f> z /rictly practical purposes are conc]n$1 ! answ] mu/ be t !re is none4 ,?us ,,maskelyne1 ! fif? ,a/ronom] ,royal1 re/rict$ 8 obs]vations to "s ?irty-six />s1 :i* 7 all t he ne$$ = 8 ,nautical ,almanac1 & ^!1 ) p]haps a few additions1 w\ld be suffici5t = all purely practical ends4 ,b !re is 9 man a re/less1 resi/less passion = k--= k = its own sake--t is always compell+ him to answ] ! *all5ge ( ! unkn[n4 ,! secret hid beh9d ! hills1 or across ! seas1 has drawn ! explor] 9 all ages2 & ! secret hid beh9d ! />s has be5 a magnet n less p[]ful4 ,s catalogues ( />s h be5 made1 & made aga91 & enl>g$ & repeat$2 in/rum5ts ( ev]-increas+ delicacy h be5 built 9 ord] to det]m9e ! positions ( />s1 & obs]vations h be5 made ) ev]-increas+ c>e & ref9em5t4 ,x is k = its own sake t is long$ =1 k t c only be won by inf9ite pati5ce & c>e4 ,! *ief in/rum5t us$ 9 mak+ a /> catalogue is call$ a transit circle2 two great /one pill>s are set up1 ea* c>ry+ "o end ( an axis1 & ! axis c>ries a telescope4 ,! telescope c turn r\nd l a :eel1 9 "o direction only2 x po9ts due nor? or due s\?4 ,a circle c>efully divid$ into degrees & fractions ( a degree is atta*$ to ! telescope4 ,9 ! c\rse ( ! tw5ty-f\r h\rs e /> above ! horizon ( ! obs]vatory mu/ come at lea/ once )9 ! range ( ?is telescope1 & at t mom5t ! obs]v] po9ts ! telescope to ! #hc />1 & notes ! "t by 8 clock :5 ! /> cross$ ! spid]'s ?reads1 :i* are fitt$ 9 ! focus ( 8 eye-piece4 ,he also notes ! angle at :i* ! telescope 0 incl9$ to ! horizon by read+ ! divisions ( 8 circle4 ,= by ^! two--! "t :5 ! /> pass$ be=e ! telescope & ! angle at :i* ! telescope 0 incl9$--he is able to fix ! position ( ! />4 ,b :y %\ld catalogues be repeat$8 ,:5 once ! position ( a /> has be5 obs]v$1 :y tr\ble to obs]ve x aga98 ,w n ! record s]ve 9 p]petuity8 ,! answ]s to ^! que/ions h be5 giv5 by /> catalogues !mselves1 or h come out 9 ! process ( mak+ !m4 ,! ,e>? rotates on its axis & revolves r\nd ! ,sun4 ,b t axis also has a roll+ motion ( its own1 & gives rise to an app>5t motion ( ! />s call$ ,precession4 ,hipp>*us discov]$ ?is effect :ile at "w on 8 catalogue1 & our k ( ! am\nt ( ,precession enables u to fix ! date :5 ! con/ellations 7 design$4 ,simil>ly1 ,bradley discov]$ two fur!r app>5t motions ( ! />s--,ab]ration & ,nutation4 ,( ^!1 ! fir/ arises f ! fact t ! light com+ f ! />s moves ) an inconceivable spe$1 b does n cross f /> to ,e>? in/antly2 x takes an appreciable1 ev5 a long1 "t to make ! j\rney4 ,b ! ,e>? is travell+ r\nd ! ,sun1 & !re=e cont9ually *ang+ its direction ( motion1 & 9 consequ5ce !re is an app>5t *ange 9 ! direction 9 :i* ! /> is se54 ,! *ange is v small1 = ?\gh ! ,e>? moves #ah- miles 9 a second1 light travels #aj1jjj times z fa/4 ,/>s !re=e are deflect$ f _! true positions by ,ab]ration1 by #hd an extreme am\nt ( #bj4dg ( arc1 t be+ ! angle %[n by an object t is slightly m di/ant ?an #aj1jjj times its diamet]4 ,! axis ( ! ,e>? n only rolls on itself1 b x does s ) a slight /agg]+1 nodd+ motion1 due to ! attractions ( ! ,sun & ,moon1 kn[n z ,nutation4 ,& ! axis does n rema9 fix$ 9 ! solid sub/ance ( ! ,e>?1 b moves ab\t irregul>ly 9 an area ( ab\t #fj feet 9 diamet]4 ,! positions ( ! nor? & s\? poles are !re=e n precisely fix$1 b move1 produc+ :at is kn[n z ! ,v>iation ( ,latitude4 ,!n />-places h to be correct$ = ! effect ( our own atmosph]e1 i4e4 refraction1 & = errors ( ! in/rum5ts by :i* _! places are det]m9$4 ,& :5 all ^! h be5 all[$ =1 ! result /&s out t diff]5t />s h real movem5t ( _! own--_! ,prop] ,motions4 ,no />s are really fix$2 ! "n fix$ />s is a tradition ( a "t :5 obs]vation 0 too r\gh to detect t any ( ! heav5ly bodies o!r ?an ! planets 7 9 motion4 ,b no?+ is fix$4 ,! ,e>? on :i* we /& has _m diff]5t motions2 ! />s are all 9 headlong flight4 ,& f ?is motion ( ! />s x has be5 le>n$ t ! ,sun too moves4 ,:5 ,cop]nicus ov]?rew ! ,ptolemaic !ory & %[$ t ! ,e>? moves r\nd ! ,sun1 x 0 natural t m5 %\ld be satisfi$ to take ?is z ! c5tre ( all ?+s1 fix$ & immutable4 ,x is n s4 ,j z a travell] driv+ ?r\gh a wood sees ! trees 9 front app>5tly op5 out & drift rapidly pa/ him on ei!r h&1 & !n sl[ly close toge!r beh9d him1 s ,sir ,,william ,,h]s*el %[$ t ! />s 9 "o #he "p ( ! heav5s appe> to be op5+ out1 or sl[ly mov+ ap>t1 :ile 9 ! opposite "p !re seems to be a slight t5d5cy = !m to come toge!r1 & 9 a belt midway betwe5 ! two ! t5d5cy is = a some:at quick] motion t[>d ! second po9t4 ,& ! explanation is ! same 9 ! "o case z 9 ! o!r--! real movem5t is ) ! obs]v]4 ,! ,sun ) all its planets & small] att5dants is ru%+ onw>d1 onw>d1 t[>ds a po9t ne> ! bord]s ( ! con/ellations ,lyra & ,h]cules1 at ! rate ( ab\t twelve miles p] second4 ,"p ( ! ,prop] ,motions ( ! />s are ?us only app>5t1 be+ due to ! actual motion ( ! ,sun--! ,sun's ,way1 z x is call$--b "p ( ! ,prop] ,motions belong to ! />s !mselves2 !y are really 9 motion1 & ?is n 9 a haphaz>d1 r&om mann]4 ,= rec5tly ,,kapteyn & o!r work]s 9 ! same field h br\ght to light ! fact ( ,/>-,drift1 i4e4 t _m ( ! />s are travell+ 9 associat$ companies4 ,?is may be illu/rat$ by ! sev5 bright />s t make up ! well-kn[n gr\p ( ! ,pl\gh1 or ,*>les's ,wa91 z c\ntry p call x4 ,= ! two />s ( ! sev5 t are fur!/ ap>t 9 ! sky are mov+ toge!r 9 "o direction1 & ! o!r five 9 ano!r4 ,ano!r result ( ! close /udy ( ! heav5s involv$ 9 ! mak+ ( /> catalogues has be5 ! detection ( ,,d\ble ,,/>s--/>s t n only appe> to be ne> toge!r b are really s4 ,q a di/9ct & important dep>tm5t ( a/ronomy has aris5 deal+ ) ! cont9ual obs]vation & measurem5t ( ^! objects4 ,= _m d\ble />s are 9 motion r\nd ea* o!r 9 ob$i5ce to ! law ( gravitation1 & _! orbits h be5 comput$4 #hf ,"s ( ^! sy/ems conta9 ?ree or ev5 f\r memb]s4 ,b 9 e case ! small] body %9es by its own light2 we h no in/ance 9 ^! d\ble />s ( a sun att5d$ by a planet2 9 ea* case x is a sun ) a companion sun4 ,! fir/ d\ble /> to be obs]v$ z su* 0 "o ( ! sev5 />s ( ! ,pl\gh4 ,x is ! middle /> 9 ! ,pl\gh h&le1 & has a fa9t /> ne> x t is visible to any ord9>ily good sight4 ,/> catalogues & ! "w ( prep>+ !m h br\ght out ano!r class--,,v>iable ,,/>s4 ,z ! places ( />s are n fix$1 s nei!r are _! brightnesses1 & "s *ange _! brightness quickly1 ev5 z se5 by ! nak$ eye4 ,"o ( ^! is call$ ,algol1 i4e4 ! ,demon ,/>1 & is 9 ! con/ellation ,p]seus4 ,! anci5t ,greeks divid$ all />s visible to ! nak$ eye into six classes1 or magnitudes1 accord+ to _! brightness1 ! brighte/ />s be+ said to be ( ! fir/ magnitude1 ^? n q s bright ( ! second1 & s on4 ,algol is !n usually class$ z a /> ( ! second magnitude1 & = two days & a half x reta9s its brightness un*ang$4 ,!n x beg9s to fade1 & = f\r & a half h\rs its brightness decl9es1 until two-?irds ( x has gone4 ,no fur!r *ange takes place = ab\t tw5ty m9utes1 aft] :i* ! light beg9s to increase aga91 & 9 ano!r f\r & a half h\rs x is z bright z ev]1 to g ?r\gh ! same *anges aga9 aft] ano!r int]val ( two days & a half4 ,algol is a d\ble />1 b1 unlike ^? />s t we "k "u t "n1 ! companion is d>k1 b is ne>ly z l>ge z its sun1 & is v close to x1 mov+ r\nd x 9 a little less ?an ?ree days4 ,at "o po9t ( its orbit x comes betwe5 ,algol & ! ,e>?1 #hg & ,algol suff]s1 f our po9t ( view1 a p>tial eclipse4 ,!re are _m o!r cases ( v>iable />s ( ?is k9d 9 :i* ! v>iation is caus$ by a d>k companion mov+ r\nd ! bright />1 & eclips+ x once 9 ea* revolution2 & ! diamet]s & di/ances ( "s ( ^! h be5 comput$1 %[+ t 9 "s cases ! two />s are almo/ 9 contact4 ,9 "s in/ances ! companion is a dull b n a d>k />2 x gives a c]ta9 am\nt ( light4 ,:5 ?is is ! case !re is a fall ( light twice 9 ! p]iod--once :5 ! fa9t] /> p>tly eclipses ! bright]1 once :5 ! bright] /> p>tly eclipses ! fa9t]4 ,b n all v>iable />s are ( ?is k9d4 ,!re is a /> 9 ! con/ellation ,cetus :i* is sometimes ( ! second magnitude1 at :i* brightness x may rema9 = ab\t a =tnight4 ,!n x w gradually dim9i% 9 brightness = n9e or t5 weeks1 until x is lo/ to ! unassi/$ sight1 & aft] six mon?s ( invisibility x reappe>s & increases dur+ ano!r n9e or t5 weeks to ano!r maximum4 ,mira1 i4e4 wond]ful />1 z ?is v>iable is call$1 is ab\t #ajjj times z bright at maximum z at m9imum1 b "s maxima are fa9t] ?an o!rs2 nei!r is ! p]iod ( v>iation always ! same4 ,x is cle> t v>iation ( ?is k9d _c be caus$ by an eclipse1 & ?\gh _m !ories h be5 sugge/$1 ! long-p]iod v>iables1 ( :i* ,mira is ! type1 z yet rema9 )\t a complete explanation4 ,m rem>kable /ill are ! ,,new ,,/>s--/>s t sudd5ly bur/ out into view1 & !n quickly fade away1 z if a beacon out 9 ! /ell> dep?s _h sudd5ly be5 fir$4 ,"o ( ^! sugge/$ to ,hipp>*us ! ne$ = a catalogue ( ! #hh />s2 ano!r1 ! s-call$ ,pilgrim ,/>1 9 ! ye> #aegb 0 ! means ( fix+ ! att5tion ( ,ty*o ,brahe ^u a/ronomy2 a ?ird 9 #afjd 0 obs]v$ & fully describ$ by ,kepl]4 ,! real mean+ ( ^! new1 or tempor>y1 />s 0 n und]/ood until ! spectroscope 0 appli$ to a/ronomy4 ,!y w !re=e be treat$ 9 ! volume ( ?is s]ies to be devot$ to t subject4 ,x ne$ only be m5tion$ "h t _! appe>ance is evid5tly due to "s k9d ( collision betwe5 cele/ial bodies1 produc+ an enorm\s & in/antane\s developm5t ( light & heat4 ,^! ,new ,/>s d n occur 9 all p>ts ( ! heav5s4 ,ev5 a ha/y glance at ! sky w %[ t ! />s are n equally scatt]$1 b t a broad belt app>5tly made up ( an imm5se numb] ( v small />s divides !m into two p>ts4 ,,! ,,milky ,,way1 or ,,galaxy1 z ?is belt is call$1 bridges ! heav5s at midnight1 e>ly 9 ,octob]1 l an enorm\s ar*1 re/+ "o foot on ! horizon 9 ! ea/1 & ! o!r 9 ! we/1 & pass+ ?r\gh ! ,z5i?1 i4e4 ! po9t ov]head4 ,x is on ?is belt ( small />s--on ! ,milky ,way--t ,new ,/>s are mo/ apt to break out4 ,! region ( ! ,milky ,way is ri*] 9 />s ?an are ! heav5s 9 g5]al4 ,b x v>ies itself also 9 ri*ness 9 a rem>kable degree4 ,9 "s places ! />s1 z se5 on "s ( ! wond]ful photographs tak5 by ,e4 ,e4 ,,b>n>d1 seem almo/ to =m a cont9u\s wall2 9 o!r places1 close at h&1 b>r5 spots appe> t look inky black by contra/4 ,& ! ,/> ,clu/]s1 />s evid5tly cr[d$ toge!r1 are frequ5t 9 ! ,milky ,way4 ,& yet aga9 beside ! />s ! telescope reveals #hi to u ! ,,nebul4 ,"s ( ^! are ! ,irregul> ,nebul--wide-/ret*+1 cl\dy1 diffus$ masses ( filmy light1 l ! ,great ,nebula 9 ,orion4 ,o!rs are fa9t b m def9$ objects1 "s ( !m ) small circul> discs1 & look+ l a v dim ,uranus1 or ev5 l ,saturn--t is to say1 l a planet ) a r+ r\nd its equator4 ,?is class are !re=e kn[n z ,planet>y ,nebul1 &1 :5 bright en\gh to %[ traces ( col\r1 appe> gre5 or gre5i% blue4 ,^! are1 h[ev]1 comp>atively r>e4 ,o!r ( ^! fa9t1 filmy objects are kn[n z ! ,:ite ,nebul1 & are n[ c\nt$ by ?\s&s4 ,!y affect ! spiral =m4 ,sometimes ! spiral is se5 fully pres5t$2 sometimes x is se5 edgewise2 sometimes m or less =e%ort5$1 b 9 g5]al ! spiral "* c be detect$4 ,& ^! ,:ite ,nebul appe> to %un ! ,galaxy z mu* z ! ,planet>y ,nebula2 & ,/> ,clu/]s pref] x2 inde$ ! "p ( ! nor!rn heav5s mo/ remote f ! ,milky ,way is simply cr[d$ ) !m4 ,x c be by no accid5t or *ance t 9 ! va/ edifice ( ! heav5s objects ( c]ta9 classes %\ld cr[d into ! belt ( ! ,milky ,way1 & o!r classes avoid x2 x po9ts to ! :ole =m+ a s+le gr[?1 an ess5tial unity4 ,= !re is b "o belt 9 ! heav5s1 l ! ,milky ,way1 a belt 9 :i* small />s1 ,new ,/>s1 & ,planet>y ,nebul f9d _! fav\rite home2 & t belt encircles ! entire heav5s2 & simil>ly t belt is ! only region f :i* ! ,:ite ,nebul appe> to be repell$4 ,! ,milky ,way =ms ! f\ndation1 ! /rong & buttress$ wall ( ! cele/ial build+2 ! ,:ite ,nebul close 9 ! ro( ( its dome4 #ij ,& h[ va/ may t /ructure be--h[ f> is x f wall to wall8 ,t1 z yet1 we c only guess4 ,b ! />s ^: di/ances we c measure1 ! />s ^: drift+ we c wat*1 almo/ inf9itely di/ant z !y are1 c>ry u b a small "p ( ! way4 ,/ill1 f little h9ts ga!r$ "h & !re1 we are able to guess t1 ?\gh ! ne>e/ /> to u is ne>ly #cjj1jjj times z f> z ! ,sun1 yet we mu/ ov]pass ! di/ance ( t /> #ajjj times be=e we %all h rea*$ ! fur!r conf9es ( ! ,galaxy4 ,nor is ! end 9 sight ev5 !re4 ,?is is1 9 briefe/ outl9e1 ! ,/ory ( ,a/ronomy4 ,x has l$ u f a "t :5 m5 7 acqua9t$ ) only a few squ>e miles ( ! ,e>?1 & knew no?+ ( its size & %ape1 or ( its relation to ! mov+ lights :i* %one d[n f above1 on to our pres5t conception ( our place 9 a univ]se ( suns ( :i* ! va/ness1 glory1 & complexity surpass our utmo/ p[]s ( expression4 ,! sci5ce began 9 ! desire to use ,sun1 ,moon1 & />s z timekeep]s1 b z ! ex]cise ( ord]$ sight & ord]$ ?\ght br\ght k1 k began to be desir$1 n = any advantage x might br+1 b = its own sake4 ,& ! pursuit itself has br\ght its own rew>d 9 t x has increas$ m5's p[]s1 & made !m ke5] 9 obs]vation1 cle>] 9 reason+1 sur] 9 inf]5ce4 ,! pursuit inde$ kn[s no end+2 ! que/ions to be answ]$ t lie be=e u are n[ m num]\s ?an ev] !y h be51 & ! call ( ! heav5s gr[s m insi/5t3 ,,lift ,,up ,,y\r ,,eyes ,,on ,,high4 #ia ,,books ,,to ,,read ,,popul> ,,g5]al ,,descriptions3-- ,sir ,r4 ,s4 ,ball4--,/>-,l&4 7,cassell47 ,agnes ,gib]ne4---,sun1 ,moon & ,/>s4 7,seeley47 ,w4 ,t4 ,lynn4--,cele/ial ,motions4 7,/an=d47 ,a4 ,w4 ,maund]4---,! ,heav5s & _! ,/ory4 7,culley47 ,simon ,newcomb4--,a/ronomy = ,ev]ybody4 7,isbi/]47 ,,= ,,beg9n]s ,,9 ,,obs]vation3-- ,w4 ,f4 ,d5n+4--,telescopic ,"w = ,/>light ,ev5+s4 7,taylor ,francis47 ,e4 ,w4 ,maund]4--,a/ronomy )\t a ,telescope4 7,?ack]47 ,ar?ur ,p4 ,norton4--,a ,/> ,atlas & ,telescopic ,h&book4 7,gall ,+lis47 ,g>rett ,p4 ,s]viss4--,a/ronomy ) an ,op]a-,glass4 7,appleton47 ,,/>-,,atlases3-- ,rev4 ,j4 ,gall--,an ,easy ,guide to ! ,con/ellations4 7,gall & ,+lis47 ,e4 ,m',clure & ,h4 ,j4 ,kle94--,/>-,atlas4 7,society = ,promot+ ,*ri/ian ,k47 ,r4 ,a4 ,proctor4--,new ,/> ,atlas4 7,longmans47 ,,a/ronomical ,,in/rum5ts ,,& ,,me?ods3-- ,sir ,g4 ,b4 ,airy4--,popul> ,a/ronomy2 ,lectures deliv]$ at ,ipswi*4 7,macmillan47 ,e4 ,w4 ,maund]4--,royal ,obs]vatory1 ,gre5wi*2 its ,hi/ory & ,"w4 7,religi\s ,tract ,society47 #ib ,,g5]al ,,text-,,books3-- ,cl]ke1 ,f[l] ,gore4--,concise ,a/ronomy4 7,hut*9son47 ,simon ,newcomb4--,popul> ,a/ronomy4 7,macmillan47 ,c4 ,a4 ,"y4--,manual ( ,a/ronomy4 7,g9n47 ,,special ,,subjects3-- ,rev4 ,e4 ,l$g]4--,! ,sun2 its ,planets & ,satellites4 7,/an=d47 ,c4 ,a4 ,"y4--,! ,sun4 7,kegan ,paul47 ,mrs4 ,todd4--,total ,eclipses4 7,sampson ,l[47 ,nasmy? & ,c>p5t]4--,! ,moon4 7,john ,murray47 ,p]cival ,l[ell4--,m>s4 7,longmans47 ,ell5 ,m4 ,cl]ke4--,jupit]4 7,/an=d47 ,e4 ,a4 ,proctor4--,saturn & its ,sy/em4 7,longmans47 ,w4 ,t4 ,lynn4--,rem>kable ,comets4 7,/an=d47 ,e4 ,w4 ,maund]4--,! ,a/ronomy ( ! ,bible4 7,hodd] & ,/\ghton47 ,,hi/orical3-- ,w4 ,w4 ,bryant4--,hi/ory ( ,a/ronomy4 7,me?u547 ,agnes ,m4 ,cl]ke4--,hi/ory ( ,a/ronomy 9 ! ,n9ete5? ,c5tury4 7,a4 ,c4 ,black47 ,george ,=bes4--,hi/ory ( ,a/ronomy4 7,watts47 ,,biographical3-- ,sir ,e4 ,s4 ,ball4--,great ,a/ronom]s4 7,isbi/]47 ,agnes ,m4 ,cl]ke4--,! ,h]s*els & ,mod]n ,a/ronomy4 7,cassell47 ,sir ,o4 ,lodge4--,pione]s ( ,sci5ce4 7,macmillan47 #ic ,,index ,,ab]ration1 #hc ,a*illes 7,m9or planet71 #ch ,adams1 ,john ,c41 #ci ,airy1 #ci ,algol1 #hf ,&rom$es 7,meteors71 #hj ,apsides1 #bd1 #bh ,argel&]1 #ha ,,b>n>d1 ,e4 ,e41 #hh ,be>1 ,!1 #ad ,biela's ,comet1 #hj ,b\v>d1 #ci ,bradley1 #ha1 #hc ,bremik]1 #dj ,,catalogues 7/>71 #ha-hc ,c5tauri1 ,alpha1 #ec ,c]es 7,m9or planet71 #ch ,*allis1 #dj ,*>les ,,ii41 #ej ,*romosph]e1 #gc ,*ronomet]1 #ej ,clairaut1 #cf ,columbus1 #dh ,comets1 #cf ,comet1 ,halley's1 #cg ---- ,biela's1 #hj ,conic ,sections1 #cd ,con/ellations1 !1 #ae ---- date (1 #af ,cook1 ,capt41 #ej ,cop]nicus1 #bf1 #ed1 #hd ,cop]nicus 7,lun> crat]71 #ei1 #fj ,corona1 #gc ,c[ell1 #cg ,crommel91 #cg ,,degrees1 #dc ,dollond1 #dg ,d\ble />s1 #he ,,e>?1 =m (1 #af ---- size (1 #ag1 #cc ,eclipses1 #gb ,ecliptic1 #ba ,ellipse1 #bh ,epicycle1 #be ,erato/h5es1 #ag ,eros 7,m9or planet71 #ch1 #eb ,eudoxus1 #ba ,exc5tric1 #bd ,eye-piece1 #de ,,facul1 #gj ,flam/e$1 #ej ,,galileo1 #dd ,galle1 #dj ,gascoigne1 #df ,gravitation1 ,law (1 #cd ,,hall1 ,,*e/] ,,moor1 #dg ,halley1 #cf ,halley's ,comet1 #cg ,h>rison1 ,john1 #ej ,h]s*el1 ,sir ,w41 #cg1 #dg1 #hd ,hipp>*us1 #bd1 #ha1 #hc1 #hg ,hyp]bola1 #cd ,,job1 ,book (1 #ab1 #ad ,juno 7,m9or planet71 #ch ,jupit]1 #ah1 #cb1 #gg-gh ,,kapteyn1 #he ,kepl]1 #bh1 #dd1 #hh ,kepl]'s ,laws1 #bi ,kepl] 7,lun> crat]71 #ei ,,langley1 #gd ,latitude1 ,v>iation (1 #hd ,leonids 7,meteors71 #hj ,lev]ri]1 #ci ,l[ell1 #fc1 #fd ,lyrids 7,meteors71 #hj ,,magnetic ,,/orm1 #gf ,magnetism1 ,e>?'s1 #gf ,magnitudes ( />s1 #hf ,m>e ,imbrium1 #ei ,m>s1 #ah1 #eb1 #fb-ff ---- ,canals (1 #fc ,maskelyne1 #ej1 #hb ,maund]1 ,mrs4 ,walt]1 #gb1 #gd ,m]cury1 #ag1 #ah1 #bg1 #cb1 #ff-fg ,meteors1 #gi1 #hj ,micromet]1 #df ,milky ,way1 #ec1 #hh ,m9or ,planets1 #ch1 #eb ,m9utes ( arc1 #dd ,mira1 #hg ,moon1 #aa1 #ad1 #ba1 #cb1 #cc1 #di1 #ee-fb ---- di/ance (1 #ea ,nautical ,almanac1 #ej1 #hb ,navigation1 #di ,nebul1 #hi ,neptune1 #dj1 #gi ,newcomb1 #fe ,new />s1 #hg ,newton1 #bi1 #ca1 #dg ,newton's ,laws ( motion1 #ca ,nodes1 #ce ,nutation1 #hc1 #hd ,,oases ( ,m>s1 #fd ,obelisks1 #db ,object glass1 #de ,obs]vatories1 ,b]l91 #ej ---- ,cop5hag51 #ej ---- ,gre5wi*1 #ej ---- ,mt4 ,wilson1 #dh ---- ,p>is1 #ej ---- ,pulk[a1 #ej ---- ,/4 ,pet]sburg1 #ej ---- ,wa%+ton1 #ej ---- ,y]kes1 #dg ,,pallas 7,m9or planet71 #ch ,p>abola1 #cd ,p]seids 7,meteors71 #hj ,photography1 #df ,photosph]e1 #fi ,pilgrim />1 #hh ,piazzi1 #ch ,planets1 #ag ,pole ( ! ,heav5s1 #ac ,pontc\lant1 #cg ,precession ( ! ,equ9oxes1 #cf1 #hc ,pr9cipia1 #cf ,prom95ces1 #gc ,ptolemu 7,lun> crat]71 #fj ,ptolemy1 #bd1 #ha ,,radiant ,,po9ts1 #hj ,radius ,vector1 #bh ,reflectors1 #dg ,refractors1 #dg ,,saturn1 #ah1 #gh-gi ,s*iap>elli1 #fc ,s*wabe1 #fi ,seconds ( arc1 #dd ,sirius1 #ec ,sol> ,sy/em1 ,tables (1 #ef-eh ,som]ville1 ,mrs41 #hi ,sph]es1 ,planet>y1 #ba ,spr]1 #ga ,spr]'s ,law1 #ga ,/> catalogues1 #ha-hc ---- clu/]s1 #hh ---- drift1 #he ,/>s1 fix$1 #hd ---- prop] motions (1 #hd ,sun1 #aa1 #ab1 #ad1 #ba1 #cb1 #fg-gg ---- di/ance (1 #ea ---- dials1 #dc ,sun spots1 #fi ---- spot maximum1 #ga ---- ---- m9imum1 #ga ,sun's ,way1 #he ,,telescope1 ,inv5tion (1 #de ,transit ,circle1 #hb ,ty*o ,brahe1 #bg1 #dd1 #hh ,ty*o 7,lun> crat]71 #ei1 #fj1 #fa ,,uranus1 #ch1 #gi ,,v>iable />s1 #hf ---- ----1 ,long p]iod1 #hg ,v5us1 #ah1 #bg1 #fg ,ve/a 7,m9or planet71 #ch ,,"y1 ,c4 ,a41 #gd ,,z5i?1 #ag1 #hh ,zodiac1 ,signs (1 #ad1 #ae1 #af1 #dc ,pr9t$ by ,,ballantyne1 ,,hanson ,co4 ,ed9burgh ,london 99 99 99 99 99 ,we h no?+ b ! highe/ praise = ^! little books1 & no "o :o exam9es !m w h any?+ else4--,we/m9/] ,gazette1 #bbnd ,june #aiab4 ,,! ,,p',s ,,books ,,! ,,fir/ ,,n9ety ,,volumes ,! volumes issu$ are m>k$ ) an a/]isk ,,sci5ce #a4 ,! ,f\ndations ( ,sci5ce 4 4 4 ,by ,w4 ,c4 ,d4 ,:e?am1 ,m4,a41 ,f4,r4,s4 #b4 ,embryology--,! ,beg9n+s ( ,life 4 4 4 ,by ,pr(4 ,g]ald ,leighton1 ,m4,d4 #c4 ,biology 4 4 4 ,by ,pr(4 ,w4 ,d4 ,h5d]son1 ,m4,a4 #d4 ,zoology3 ,! ,/udy ( ,animal ,life 4 4 4 ,by ,pr(4 ,e4 ,w4 ,mac,bride1 ,m4,a41 ,f4,r4,s4 #e4 ,botany2 ,! ,mod]n ,/udy ( ,plants 4 4 4 ,by ,m4 ,c4 ,/opes1 ,d4,sc41 ,ph4,d41 ,f4,l4,s4 #f4 ,bact]iology 4 4 4 ,by ,w4 ,e4 ,c>negie ,dickson1 ,m4,d4 #g4 ,! ,/ructure ( ! ,e>? 4 4 4 ,by ,pr(4 ,t4 ,g4 ,bonney1 ,f4,r4,s4 #h4 ,evolution 4 4 4 ,by ,e4 ,s4 ,goodri*1 ,m4,a41 ,f4,r4,s4 #i4 ,d>w9 4 4 4 ,by ,pr(4 ,w4 ,g>/ang1 ,m4,a41 ,d4,sc4 #aj4 ,h]$ity 4 4 4 ,by ,j4 ,a4 ,s4 ,watson1 ,b4,sc4 #aa4 ,inorganic ,*emi/ry 4 4 4 ,by ,pr(4 ,e4 ,c4 ,c4 ,baly1 ,f4,r4,s4 #ab4 ,organic ,*emi/ry 4 4 4 ,by ,pr(4 ,j4 ,b4 ,coh51 ,b4,sc41 ,f4,r4,s4 #ac4 ,! ,pr9ciples ( ,electricity 4 4 4 ,by ,norman ,k4 ,campbell1 ,m4,a4 #ad4 ,radiation 4 4 4 ,by ,p4 ,phillips1 ,d4,sc4 #ae4 ,! ,sci5ce ( ! ,/>s 4 4 4 ,by ,e4 ,w4 ,maund]1 ,f4,r4,a4,s4 #af4 ,! ,sci5ce ( ,light 4 4 4 ,by ,p4 ,phillips1 ,d4,sc4 #ag4 ,wea!r ,sci5ce 4 4 4 ,by ,r4 ,g4 ,k4 ,lempf]t1 ,m4,a4 #ah4 ,hypnotism & ,self-,education 4 4 4 ,by ,a4 ,m4 ,hut*ison1 ,m4,d4 #ai4 ,! ,baby3 ,a ,"m's ,book 4 4 4 ,by a ,univ]sity ,woman4 #bj4 ,y\? & ,sex--,dang]s & ,safegu>ds = ,boys & ,girls 4 4 4 ,by ,m>y ,s*>lieb1 ,m4,d41 ,m4,s41 & ,f4 ,ar?ur ,sibly1 ,m4,a41 ,,ll4,d4 #ba4 ,m>riage & ,mo!rhood 4 4 4 ,by ,h4 ,s4 ,davidson1 ,m4,b41 ,f4,r4,c4,s4,e4 #bb4 ,"l ,kelv9 4 4 4 ,by ,a4 ,russell1 ,m4,a41 ,d4,sc41 ,m4,i4,e4,e4 #bc4 ,huxley 4 4 4 ,by ,pr(essor ,g4 ,leighton1 ,m4,d4 #bd4 ,sir ,william ,hugg9s & ,spectroscopic ,a/ronomy 4 4 4 ,by ,e4 ,w4 ,maund]1 ,f4,r4,a4,s41 ( ! ,royal ,obs]vatory1 ,gre5wi*4 #fb4 ,practical ,a/ronomy 4 4 4 ,by ,h4 ,macph]son1 ,jr41 ,f4,r4,a4,s4 #fc4 ,aviation 4 4 4 ,by ,sydney ,f4 ,walk]1 ,r4,n4 #fd4 ,navigation 4 4 4 ,by ,william ,hall1 ,r4,n41 ,b4,a4 #fe4 ,pond ,life 4 4 4 ,by ,e4 ,c4 ,a%1 ,m4,r4,a4,c4 #ff4 ,dietetics 4 4 4 ,by ,alex4 ,bryce1 ,m4,d41 ,d4,p4,h4 ,,philosophy ,,& ,,religion #be4 ,! ,mean+ ( ,philosophy 4 4 4 ,by ,pr(4 ,a4 ,e4 ,taylor1 ,m4,a41 ,f4,b4,a4 #bf4 ,h5ri ,b]gson 4 4 4 ,by ,h4 ,wildon ,c>r1 ,litt4,d4 #bg4 ,psy*ology 4 4 4 ,by ,h4 ,j4 ,watt1 ,m4,a41 ,ph4,d41 ,d4,phil4 #bh4 ,e?ics 4 4 4 ,by ,canon ,ra%dall1 ,d4,litt41 ,f4,b4,a4 #bi4 ,kant's ,philosophy 4 4 4 ,by ,a4 ,d4 ,l9dsay1 ,m4,a4 #cj4 ,! ,tea*+ ( ,plato 4 4 4 ,by ,a4 ,d4 ,l9dsay1 ,m4,a4 #fg4 ,ari/otle 4 4 4 ,by ,pr(4 ,a4 ,e4 ,taylor1 ,m4,a41 ,f4,b4,a4 #fh4 ,fri$ri* ,nietzs*e 4 4 4 ,by ,m4 ,a4 ,mgge4 #fi4 ,euck53 ,a ,philosophy ( ,life 4 4 4 ,by ,a4 ,j4 ,jones1 ,m4,a41 ,b4,sc41 ,ph4,d4 #gj4 ,! ,exp]im5tal ,psy*ology ( ,beauty 4 4 4 ,by ,c4 ,w4 ,val5t9e1 ,b4,a41 ,d4,phil4 #ga4 ,! ,problem ( ,tru? 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