,transcrib]'s ,note ,:5 italics 7 us$ 9 ! orig9al book1 ! correspond+ text has be5 surr\nd$ by und]scores except 9 ! case ( s+le lett] v>iables us$ 9 ! ,notes section1 :]e ! italics 7 n repres5t$4 ,mix$ fractions h be5 display$ ) a hyph5 betwe5 :ole numb] & fraction = cl>ity4 ,sup]script$ *>act]s are prec$$ by & :5 m ?an "o "* is sup]script$1 !y are surr\nd$ by 4 ,?is book uses "s unusual *>act]s1 su* z ^? repres5t+ ! con/ellation ,aries 77 & ,libra 774 ,^! *>act]s may fail to display correctly if ! font y are us+ does n support !m4 ,"s corrections h be5 made to ! pr9t$ text4 ,^! are li/$ 9 a second transcrib]'s note at ! end ( ! text4 ,illu/ration3 ,,m>y ,,som]ville ,j4 ,,coop] ,sc4 ,,on ,,! ,,connexion ,,( ,,! ,,physical ,,sci5ces4 ,,by ,,m>y ,,som]ville1 ,,au?oress ,,( #8,,me*anism ,,( ,,! ,,heav5s1' ,,& #8,,physical ,,geography4' --------------------- 8,no natural ph5om5on c be adequately /udi$ 9 itself alone--b1 to be und]/ood1 x mu/ be consid]$ z x /&s connect$ ) all ,nature40--,,bacon4 --------------------- ,n9? ,edition1 completely ,revis$4 ,,london3 ,,john ,,murray1 ,,albem>le ,,/reet4 #aheh4 ,! "r ( ,translation is res]v$4 ,,london3 ,,pr9t$ ,,by ,w4 ,,cl[es ,,& ,,sons1 ,,duke ,,/reet1 ,,/am=d ,,/reet1 ,,& ,,*>+ ,,cross4 ,?is ,book is ,d$icat$ ,,to ,,h] ,,de> ,,*ildr51 ,,by ,,_! ,,affectionate ,,"m1 ,,m>y ,,som]ville4 ,flor5ce1 ,nov4 #a1 #aheh4 ,,cont5ts4 ,,introduction ,page #a ,,section ,i4 ,attraction ( a ,sph]e--,=m ( ,cele/ial ,bodies--,t]re/rial ,gravitation reta9s ! ,moon 9 h] ,orbit--,! ,heav5ly ,bodies move 9 ,conic ,sections--,gravitation ,proportional to ,mass--,gravitation ( ! ,p>ticles ( ,matt]--,figure ( ! ,planets--,h[ x affects ! ,motions ( _! ,satellites--,rotation & ,translation impress$ by ! same ,impulse--,motion ( ! ,sun & ,sol> ,sy/em #d ,,section ,,ii4 ,elliptical ,motion--,mean & ,true ,motion--,equ9octial--,ecliptic--,equ9ox es--,mean & ,true ,longitude--,equation ( ,c5tre--,incl9ation ( ! ,orbits ( ,planets--,cele/ial ,latitude--,nodes--,elem5ts ( an ,orbit--,undi/urb$ or ,elliptical ,orbits--,great ,incl9ation ( ! ,orbits ( ! ,new ,planets--,univ]sal ,gravitation ! ,cause ( ,p]turbations 9 ! ,motions ( ! ,heav5ly ,bodies--,problem ( ! ,?ree ,bodies--,/ability ( ,sol> ,sy/em dep5ds ^u ! ,primitive ,mom5tum ( ! ,bodies #h ,,section ,,iii4 ,p]turbations1 ,p]iodic & ,secul>--,di/urb+ ,action equival5t to ?ree ,p>tial ,=ces--,tang5tial ,=ce ! cause ( ! ,p]iodic ,inequalities 9 ,longitude1 & ,secul> ,inequalities 9 ! ,=m & ,position ( ! ,orbit 9 its own ,plane--,radial ,=ce ! cause ( ,v>iations 9 ! ,planet's ,di/ance f ! ,sun--,x comb9es ) ! ,tang5tial ,=ce to produce ! ,secul> ,v>iations 9 ! ,=m & ,position ( ! ,orbit 9 its own ,plane--,p]p5dicul> ,=ce ! cause ( ,p]iodic ,p]turbations 9 ,latitude1 & ,secul> ,v>iations 9 ! ,position ( ! ,orbit ) reg>d to ! ,plane ( ! ,ecliptic--,mean ,motion & ,major ,axis ,inv>iable--,/ability ( ,sy/em--,effects ( a ,resi/+ ,m$ium--,inv>iable ,plane ( ! ,sol> ,sy/em & ( ! ,univ]se--,great ,inequality ( ,jupit] & ,saturn #ac ,,section ,,iv4 ,!ory ( ,jupit]'s ,satellites--,effects ( ! ,figure ( ,jupit] ^u 8 ,satellites--,position ( _! ,orbits--,s+ul> ,laws among ! ,motions ( ! fir/ ,?ree ,satellites--,eclipses ( ! ,satellites--,velocity ( ,light--,ab]ration--,e!real ,m$ium--,satellites ( ,saturn & ,uranus #bg ,,section ,v4 ,lun> ,!ory--,p]iodic ,p]turbations ( ! ,moon--,equation ( ,c5tre--,evection--,v>iation--,annual ,equation--,direct & ,indirect ,action ( ,planets--,! ,moon's ,action on ! ,e>? di/urbs h] own ,motion--,exc5tricity & ,incl9ation ( ,lun> ,orbit inv>iable--,accel]ation--,secul> ,v>iation 9 ,nodes & ,p]igee--,motion ( ,nodes & ,p]igee insep>ably connect$ ) ! ,accel]ation--,nutation ( ,lun> ,orbit--,=m & ,int]nal ,/ructure ( ! ,e>? det]m9$ f x--,lun>1 ,sol>1 & ,planet>y ,eclipses--,occultations & ,lun> ,di/ances--,mean ,di/ance ( ! ,sun f ! ,e>? obta9$ f ,lun> ,!ory--,absolute ,di/ances ( ! ,planets1 h[ f\nd #cd ,,section ,,vi4 ,=m ( ! ,e>? & ,planets--,figure ( a ,homog5e\s ,sph]oid 9 ,rotation--,figure ( a ,sph]oid ( v>iable ,d5sity--,figure ( ! ,e>?1 suppos+ x to be an ,ellipsoid ( ,revolution--,m5suration ( a ,degree ( ! ,m]idian--,compression & ,size ( ! ,e>? f ,degrees ( ,m]idian--,figure ( ,e>? f ! ,p5dulum #dd ,,section ,,vii4 ,p>allax--,lun> ,p>allax f\nd f ,direct ,obs]vation--,sol> ,p>allax d$uc$ f ! ,transit ( ,v5us--,di/ance ( ! ,sun f ! ,e>?--,annual ,p>allax--,di/ance ( ! ,fix$ ,/>s #eb ,,section ,,viii4 ,masses ( ,planets t h no ,satellites det]m9$ f _! ,p]turbations--,masses ( ! o!rs obta9$ f ! ,motions ( _! ,satellites--,masses ( ! ,sun1 ! ,e>?1 ( ,jupit] & ( ! ,jovial ,sy/em--,mass ( ! ,moon--,real ,diamet]s ( ,planets1 h[ obta9$--,size ( ,sun1 ,d5sities ( ! ,heav5ly ,bodies--,=mation ( ,a/ronomical ,tables--,requisite ,data & ,means ( obta9+ !m #ee ,,section ,,ix4 ,rotation ( ! ,sun & ,planets--,saturn's ,r+s--,p]iods ( ! ,rotation ( ! ,moon & o!r ,satellites equal to ! ,p]iods ( _! ,revolutions--,=m ( ,lun> ,sph]oid--,libration1 ,aspect1 & ,con/itution ( ! ,moon--,rotation ( ,jupit]'s ,satellites #fe ,,section ,x4 ,rotation ( ! ,e>? inv>iable--,decrease 9 ! ,e>?'s mean ,temp]ature--,e>? orig9ally 9 a /ate ( ,fusion--,l5g? ( ,day con/ant--,decrease ( ,temp]ature ascrib$ by ,sir ,john ,h]s*el to ! v>iation 9 ! ,exc5tricity ( ! ,t]re/rial ,orbit--,diff]5ce 9 ! ,temp]ature ( ! two ,hemisph]es errone\sly ascrib$ to ! ,excess 9 ! ,l5g? ( ,spr+ & ,summ] 9 ! ,s\!rn ,hemisph]e2 attribut$ by ,sir ,*>les ,lyell to ! ,op]ation ( exi/+ ,causes--,?ree pr9cipal ,axes ( ,rotation--,position ( ! ,axis ( ,rotation on ! ,surface ( ! ,e>? inv>iable--,ocean n suffici5t to re/ore ! ,equilibrium ( ! ,e>? if d]ang$--,its ,d5sity & mean ,dep?--,int]nal ,/ructure ( ! ,e>? #ga ,,section ,,xi4 ,precession & ,nutation--,_! ,effects on ! ,app>5t ,places ( ! ,fix$ ,/>s #gi ,,section ,,xii4 ,mean & ,app>5t ,sid]eal ,"t--,mean & ,app>5t ,sol> ,"t--,equation ( ,"t--,engli% & ,fr5* ,subdivisions ( ,"t--,leap ,ye>--,*ri/ian ,era--,equ9octial ,"t--,rem>kable ,eras dep5d+ ^u ! ,position ( ! ,sol> ,p]igee--,inequality ( ! ,l5g?s ( ! ,seasons 9 ! two ,hemisph]es--,application ( ,a/ronomy to ,*ronology--,engli% & ,fr5* ,/&>ds ( ,weights & ,measures #hc ,,section ,,xiii4 ,tides--,=ces t produce !m--,orig9 & ,c\rse ( ,tidal ,wave--,its ,spe$--,?ree k9ds ( ,oscillations 9 ! ,ocean--,! ,semidiurnal ,tides--,equ9octial ,tides--,effects ( ! ,decl9ation ( ! ,sun & ,moon--,!ory insuffici5t )\t ,obs]vation--,direction ( ! ,tidal ,wave--,height ( ,tides--,mass ( ,moon obta9$ f h] ,action on ! ,tides--,int]f]5ce ( ,undulations--,impossibility ( a ,univ]sal ,inundation--,curr5ts #ia ,,section ,,xiv4 ,molecul> ,=ces--,p]man5cy ( ! ultimate ,p>ticles ( ,matt]--,int]/ices--,mossotti's ,!ory--,rank9's ,!ory ( ,molecul> ,vortices--,gases r$uc$ to ,liquids by ,pressure--,gravitation ( ,p>ticles--,cohesion--,cry/allization--, cleavage--,isomorphism--,m9ut5ess ( ! ,p>ticles--,height ( ,atmosph]e--,*emical ,aff9ity--,def9ite ,proportions & ,relative ,weights ( ,atoms--,f>aday's ,discov]y ) reg>d to ,aff9ity--,capill>y ,attraction #ajb ,,section ,,xv4 ,analysis ( ! ,atmosph]e--,its pressure--,law ( ,decrease 9 ,d5sity--,law ( ,decrease 9 ,temp]ature--,measurem5t ( ,heights by ! ,b>omet]--,ext5t ( ! ,atmosph]e--,b>ometrical ,v>iations--,oscillations--,trade-,w9ds- -,cl\d-,r+--,monsoons--,rotation ( ,w9ds--,laws ( ,hurricanes #aag ,,section ,,xvi4 ,s\nd--,propagation ( ,s\nd illu/rat$ by a ,field ( ,/&+ ,corn--,nature ( ,waves--,propagation ( ,s\nd ?r\gh ! ,atmosph]e--,int5sity--,noises--,a ,musical ,s\nd--,quality--,pit*--,ext5t ( ,human ,he>+--,velocity ( ,s\nd 9 ,air1 ,wat]1 & ,solids--,causes ( ! ,ob/ruction ( ,s\nd--,law ( its ,int5sity--,reflection ( ,s\nd--,e*oes--,?und]--,refraction ( ,s\nd--,int]f]5ce ( ,s\nds #abi ,,section ,,xvii4 ,vibration ( ,musical ,/r+s--,h>monic ,s\nds--,nodes--,vibration ( ,air 9 ,w9d-,in/rum5ts--,vibration ( ,solids--,vibrat+ ,plates--,bells--,h>mony--,s\nd+ ,bo>ds--,=c$ ,vibrations--,resonance--,speak+ ,ma*9es #adj ,,section ,,xviii4 ,refraction--,a/ronomical ,refraction & its ,laws--,=mation ( ,tables ( ,refraction--,t]re/rial ,refraction--,its ,quantity--,in/ances ( ,extraord9>y ,refraction--,reflection--,in/ances ( ,extraord9>y ,reflection--,loss ( ,light by ! ,absorb+ ,p[] ( ! ,atmosph]e--,app>5t ,magnitude ( ,sun & ,moon 9 ! ,horizon #aec ,,section ,,xix4 ,con/itution ( ,light accord+ to ,sir ,isaac ,newton--,absorption ( ,light--,col\rs ( ,bodies--,con/itution ( ,light accord+ to ,sir ,david ,brew/]--,new ,col\rs--,fraunh(]'s ,d>k ,l9es--,disp]sion ( ,light--,! ,a*romatic ,telescope--,homog5e\s ,light--,accid5tal & ,complem5t>y ,col\rs--,m4 ,plateau's ,exp]im5ts & ,!ory ( ,accid5tal ,col\rs #aei ,,section ,,xx4 ,int]f]5ce ( ,light--,undulatory ,!ory ( ,light--,propagation ( ,light--,newton's ,r+s--,measurem5t ( ! ,l5g? ( ! ,waves ( ,light1 & ( ! ,frequ5cy ( ! ,vibrations ( ,e!r = ea* ,col\r--,newton's ,scale ( ,col\rs--,diffraction ( ,light--,sir ,john ,h]s*el's ,!ory ( ! ,absorption ( ,light--,refraction & ,reflection ( ,light #afg ,,section ,,xxi4 ,pol>ization ( ,light--,def9$--,pol>ization by ,refraction--,prop]ties ( ! ,t\rmal9e--,d\ble ,refraction--,all d\bly ,refract$ ,light is ,pol>iz$--,prop]ties ( ,icel& ,sp>--,t\rmal9e absorbs "o ( ! two ,refract$ ,rays--,undulations ( ,natural ,light--,undulations ( ,pol>iz$ ,light--,! ,optic ,axes ( ,cry/als--,m4 ,fresnel's ,discov]ies on ! ,rays pass+ along ! ,optic ,axis--,pol>ization by ,reflection #agi ,,section ,,xxii4 ,ph5om5a exhibit$ by ! ,passage ( ,pol>iz$ ,light ?r\gh ,mica & ,sulphate ( ,lime--,! ,col\r$ ,images produc$ by ,pol>iz$ ,light pass+ ?r\gh ,cry/als hav+ "o & two ,optic ,axes--,circul> ,pol>ization--,elliptical ,pol>ization--,discov]ies ( ,,mm4 ,biot1 ,fresnel1 & ,pr(essor ,airy--,col\r$ ,images produc$ by ! ,int]f]5ce ( ,pol>iz$ ,rays--,fluoresc5ce #ahf ,,section ,,xxiii4 ,objections to ! ,undulatory ,!ory1 f a diff]5ce 9 ! ,action ( ,s\nd & ,light "u ! same circum/ances1 remov$--,! ,disp]sion ( ,light accord+ to ! ,undulatory ,!ory--,arago's f9al pro( t ! ,undulatory ,!ory is ! ,law ( ,nature #aii ,,section ,,xxiv4 ,*emical or ,photographic ,rays ( ,sol> ,spectrum--,s*eele1 ,ritt]1 & ,wolla/on's ,discov]ies--,w$gwood's & ,sir ,humphry ,davy's ,photographic ,pictures--,! ,calotype--,! ,dagu]reotype--,! ,*romatype--,! ,cyanotype--,collodion--,sir ,john ,h]s*el's ,discov]ies 9 ! ,*emical ,spectrum--,m4 ,becqu]el's ,discov]ies ( ,inactive ,l9es 9 ditto--,!rmic ,spectrum--,phosphoric ,spectrum--,electrical ,prop]ties--,p>a!rmic ,rays--,mos] & ,hunt's ,exp]im5ts--,g5]al ,/ructure & antagoni/ ,prop]ties ( ,sol> ,spectrum--,defract$ ,spectrum #bjc ,,section ,,xxv4 ,size & ,con/itution ( ! ,sun--,! ,sol> ,spots--,int5sity ( ! ,sun's ,light & ,heat--,! ,sun's ,atmosph]e--,8 influ5ce on ! ,planets--,atmosph]es ( ! ,planets--,! ,moon has none--,lun> heat--,! ,diff]5tial ,telescope--,temp]ature ( ,space--,int]nal ,heat ( ! ,e>?--,zone ( con/ant ,temp]ature--,increase ( ,heat ) ! ,dep?--,c5tral ,heat--,volcanic ,action--,quantity ( ,heat receiv$ f ! ,sun--,isogeo!rmal ,l9es--,l9e ( ,p]petual ,congelation--,climate--,iso!rmal ,l9es--,same quantity ( ,heat annually receiv$ & radiat$ by ! ,e>? #bbd ,,section ,,xxvi4 ,influ5ce ( ,temp]ature on ,vegetation--,vegetation v>ies ) ! ,latitude & ,height above ! ,sea--,geographical ,di/ribution ( ,l& ,plants--,di/ribution ( ,m>9e ,plants--,corall9es1 ,%ell-fi%1 ,reptiles1 ,insects1 ,birds1 & ,quadrup$s--,v>ieties ( ,mank9d1 yet id5tity ( ,species #bdh ,,section ,,xxvii4 ,t]re/rial ,heat--,radiation--,transmission--,mello ni's exp]im5ts--,heat 9 ,sol> ,spectrum--,pol>ization ( ,heat--,nature ( ,heat--,absorptions--,dew--,ra9--,combu/ ion--,expansion--,comp5sation ,p5dulum--,transmission ?r\gh ,cry/als--,propagation--,dynamic ,!ory ( ,heat--,me*anical equival5t ( ,heat--,lat5t ,heat is ! ,=ce ( ,expansion--,/eam--,"w p]=m$ by ,heat--,cons]vation ( ,=ce--,me*anical ,p[] 9 ! ,tides--,dynamical ,p[] ( ,light--,analogy betwe5 ,light1 ,heat1 & ,s\nd #beg ,,section ,,xxviii4 ,common or ,/atic ,electricity1 or ,electricity ( ,t5sion--,a ,dual ,p[]--,me?ods ( excit+ x--,attraction & ,repulsion--,conduction--,electrics & ,non-electrics--,induction--,dielectrics --,t5sion--,law ( ! ,electric ,=ce--,di/ribution--,laws ( ,di/ribution--,heat ( ,electricity--,electrical ,light & its ,spectrum--,velocity--,atmosph]ic ,electricity--,its cause--,electric ,cl\ds--,viol5t effects ( ,lightn+--,back ,/roke--,electric ,gl[--,phosphoresc5ce #bhb ,,section ,,xxix4 ,voltaic ,electricity--,! ,voltaic ,batt]y--,int5sity--,quantity--,/atic ,electricity1 & ,electricity 9 ,motion--,lum9\s ,effects--,mr4 ,grove on ! ,electric ,arc & ,light--,decomposition ( ,wat]--,=mation ( ,cry/als by ,voltaic ,electricity--,photo-galvanic ,engrav+--,conduction--,heat ( ,voltaic ,electricity--,electric ,fi% #big ,,section ,,xxx4 ,discov]y ( ,electro-magnetism--,deflection ( ! ,magnetic ,ne$le by a ,curr5t ( ,electricity--,direction ( ! ,=ce--,rotatory ,motion by ,electricity--,rotation ( a ,wire & a ,magnet--,rotation ( a ,magnet ab\t its ,axis--,( ,m]cury & ,wat]--,electro-,magnetic ,cyl9d] or ,helix--,susp5sion ( a ,ne$le 9 a ,helix--,electro-,magnetic ,induction--,tempor>y ,magnets--,! ,galvanomet] #cab ,,section ,,xxxi4 ,electro-,dynamics--,reciprocal ,action ( ,electric ,curr5ts--,id5tity ( ,electro-,dynamic ,cyl9d]s & ,magnets--,diff]5ces betwe5 ! ,action ( ,voltaic ,electricity & ,electricity ( ,t5sion--,effects ( a ,voltaic ,curr5t--,ampre's ,!ory--,dr4 ,f>aday's ,exp]im5t ( ,electrify+ & ,magnetis+ a ,ray ( ,light #caf ,,section ,,xxxii4 ,magneto-,electricity--,volta-,electric ,induction--,magneto-,electric ,induction--,id5tity 9 ! ,action ( ,electricity & ,magnetism--,description ( a ,magneto-,electric ,app>atus & its ,effects--,id5tity ( ,magnetism & ,electricity--,! ,subm>9e ,telegraph #cbb ,,section ,,xxxiii4 ,electricity produc$ by ,rotation--,direction ( ! ,curr5ts--,electricity f ! ,rotation ( a ,magnet--,m4 ,arago's ,exp]im5t expla9$--,rotation ( a ,plate ( ,iron betwe5 ! ,poles ( a ,magnet--,relation ( ,sub/ances to ,magnets ( ?ree ,k9ds--,!rmo-,electricity #ccj ,,section ,,xxxiv4 ,magnetism a ,dual ,p[]--,anti!tic ,"* ( ,p>amagnetism & ,diamagnetism--,! ,e>? ,p>amagnetic--,prop]ties ( ,p>amagnetic ,bodies--,pol>ity--,induction--,l9es ( ,magnetic ,=ce--,curr5ts ( ,electricity induc$ by !m--,prov$ to be ,clos$ ,curves--,analogy & ,id5tity ( ,electricity & ,magnetism--,t]re/rial ,magnetism--,mean ,values ( ! ,?ree ,magnetic ,elem5ts--,_! ,v>iations 9 ,d\ble ,progression prov$ to consi/ ( ,two ,sup]pos$ ,v>iations--,discov]y ( ! ,p]iodicity ( ! ,magnetic ,/orms--,! ,dec5nial ,p]iod ( ! ,magnetic ,elem5ts ! same ) t ( ! ,sol> ,spots--,magnetism ( ! ,atmosph]e--,diamagnetism--,action ( ,electro-,magnetism on ,p>amagnetic1 ,diamagnetic ,bodies1 & on ,copp]1 v diff]5t--,pro( ( ,diamagnetic ,pol>ity & ,induction--,magnecry/allic ,action--,effects ( ,compression1 ,heat1 & ,cleavage on ,magnetic ,bodies--,mutual ,dep5d5ce ( ,light1 ,heat1 ,electricity1 c4 c4--,! ,cons]vation ( ,=ce & ! ,p]man5cy ( ,matt] ,prim>y ,laws ( ,nature--,def9ition ( ,gravity n accord+ to t ,law--,gravity only ! ,residual ,=ce ( a ,univ]sal ,p[]--,magnetism ( ! ,e!real ,m$ium #cce ,,section ,,xxxv4 ,e!real ,m$ium--,comets--,d n di/urb ! ,sol> ,sy/em--,_! ,orbits & ,di/urbances--,m4 ,faye's ,comet probably ! same ) ,lexel's--,p]iods ( o!r ?ree kn[n--,accel]ation 9 ! mean ,motions ( ,encke's & ,biela's ,comets--,! ,%ock ( a ,comet--,di/urb+ ,action ( ! ,e>? & ,planets on ,encke's & ,biela's ,comets--,velocity ( ,comets--,! ,comet ( #abfd--,! great ,comet ( #acdc--,physical ,con/itution--,%9e by borr[$ ,light--,e/imation ( _! ,numb] #ceh ,,section ,,xxxvi4 ,! ,fix$ ,/>s--,_! ,numb]--,! ,milky ,way--,d\ble ,/>s--,b9>y ,sy/ems--,_! ,orbits & ,p]iodic ,times--,col\rs ( ! ,/>s--,/>s t h vani%$--,v>iable ,/>s--,v>iation 9 ,sun's ,light--,p>allax & ,di/ances ( ! ,fix$ ,/>s--,masses ( ! ,/>s--,comp>ative ,light ( ! ,/>s--,prop] ,motions ( ! ,/>s--,app>5t ,motions ( ! ,/>s--,motion & ,velocity ( ! ,sun & ,sol> ,sy/em--,! ,nebul--,_! ,numb]--,catalogue ( !m--,consi/ ( ,two ,classes--,diffuse ,nebul--,def9itely =m$ ,nebul--,globul> ,clu/]s--,spl5d\r ( ,milky ,way--,di/ribution ( ! ,nebul--,! ,magellanic ,cl\ds--,nebul r\nd ,args--,con/itution ( ,nebul1 & ! ,=ces t ma9ta9 !m--,meteorites & ,%oot+ ,/>s #chd ,,section ,,xxxvii4 ,diffusion ( ,matt] ?r\gh ,space--,gravitation--,its ,velocity--,simplicity ( its ,laws--,gravitation indep5d5t ( ! ,magnitude & ,di/ances ( ! ,bodies--,n imp$$ by ! int]v5tion ( any ,sub/ance--,its ,int5sity inv>iable--,g5]al ,laws--,recapitulation & ,conclusion #dbd ,,notes #dbi ,,index #dgi ,,! ,,connection ,,( ,,! ,,physical ,,sci5ces4 ,,introduction4 ,,sci5ce1 reg>d$ z ! pursuit ( tru?1 mu/ ev] af=d occupation ( consummate int]e/1 & subject ( elevat$ m$itation4 ,! contemplation ( ! works ( creation elevates ! m9d to ! admiration ( :atev] is great & noble2 accompli%+ ! object ( all /udy1 :i*1 9 ! eloqu5t language ( ,sir ,james ,mack9to%1 8is to inspire ! love ( tru?1 ( wisdom1 ( beauty--especially ( goodness1 ! highe/ beauty--& ( t supreme & et]nal ,m9d1 :i* conta9s all tru? & wisdom1 all beauty & goodness4 ,by ! love or delightful contemplation & pursuit ( ^! transc5d5t aims1 = _! own sake only1 ! m9d ( man is rais$ f l[ & p]i%able objects1 & prep>$ = ^? high de/9ies :i* are appo9t$ = all ^? :o are capable ( !m40 ,a/ronomy af=ds ! mo/ ext5sive example ( ! connection ( ! physical sci5ces4 ,9 x are comb9$ ! sci5ces ( numb] & quantity1 ( re/ & motion4 ,9 x we p]ceive ! op]ation ( a =ce :i* is mix$ up ) ev]y?+ t exi/s 9 ! heav5s or on e>?2 :i* p]vades e atom1 rules ! motions ( animate & inanimate be+s1 & is z s5sible 9 ! desc5t ( a ra9-drop z 9 ! falls ( ,niag>a2 9 ! weight ( ! air1 z 9 ! p]iods ( ! moon4 ,gravitation n only b9ds satellites to _! planet1 & planets to ! sun1 b x connects sun ) sun ?r\gh\t ! wide ext5t ( creation1 & is ! cause ( ! di/urbances1 z well z ( ! ord] ( nature2 s9ce e tremor x excites 9 any "o planet is imm$iately transmitt$ to ! f>!/ limits ( ! sy/em1 9 oscillations :i* correspond 9 _! p]iods ) ! cause produc+ !m1 l sympa!tic notes 9 music1 or vibrations f ! deep tones ( an organ4 ,! heav5s af=d ! mo/ sublime subject ( /udy :i* c be d]iv$ f sci5ce4 ,! magnitude & spl5d\r ( ! objects1 ! inconceivable rapidity ) :i* !y move1 & ! enorm\s di/ances betwe5 !m1 impress ! m9d ) "s notion ( ! en]gy t ma9ta9s !m 9 _! motions1 ) a durability to :i* we c see no limit4 ,equally conspicu\s is ! goodness ( ! great ,fir/ ,cause1 9 hav+ end[$ man ) faculties1 by :i* he c n only appreciate ! magnific5ce ( ,8 works1 b trace1 ) precision1 ! op]ation ( ,8 laws1 use ! globe he inhabits z a base :]e) to measure ! magnitude & di/ance ( ! sun & planets1 & make ! diamet] 7,note #a7 ( ! e>?'s orbit ! fir/ /ep ( a scale by :i* he may asc5d to ! />ry firmam5t4 ,su* pursuits1 :ile !y ennoble ! m9d1 at ! same "t inculcate humility1 by %[+ t !re is a b>ri] :i* no en]gy1 m5tal or physical1 c ev] enable u to pass3 t1 h[ev] pr(\ndly we may p5etrate ! dep?s ( space1 !re /ill rema9 innum]able sy/ems1 comp>$ ) :i*1 ^? app>5tly s va/ mu/ dw9dle into insignificance1 or ev5 become invisible2 & t n only man1 b ! globe he inhabits--nay1 ! :ole sy/em ( :i* x =ms s small a "p--might be annihilat$1 & its ext9ction be unp]ceiv$ 9 ! imm5sity ( creation4 ,a complete acqua9tance ) physical a/ronomy c be atta9$ by ^? only :o are well v]s$ 9 ! high] bran*es ( ma!matical & me*anical sci5ce 7,n4 #b71 & !y alone c appreciate ! extreme beauty ( ! results1 & ( ! means by :i* ^! results are obta9$4 ,x is nev]!less true1 t a suffici5t skill 9 analysis 7,n4 #c7 to foll[ ! g5]al outl9e--to see ! mutual dep5d5ce ( ! diff]5t p>ts ( ! sy/em1 & to compreh5d by :at means ! mo/ extraord9>y conclusions h be5 arriv$ at1--is )9 ! rea* ( _m :o %r9k f ! task1 appall$ by difficulties1 n m =midable ?an ^? incid5t to ! /udy ( ! elem5ts ( e bran* ( k4 ,!re is a wide di/9ction betwe5 ! degree ( ma!matical acquirem5t necess>y = mak+ discov]ies1 & t :i* is requisite = und]/&+ :at o!rs h done4 ,our k ( ext]nal objects is f\nd$ ^u exp]i5ce1 :i* furni%es facts2 ! comp>ison ( ^! facts e/abli%es relations1 f :i* ! belief t l causes w produce l effects leads to g5]al laws4 ,?us1 exp]i5ce tea*es t bodies fall at ! surface ( ! e>? ) an accel]at$ velocity1 & ) a =ce proportional to _! masses4 ,by comp>ison1 ,newton prov$ t ! =ce :i* occasions ! fall ( bodies at ! e>?'s surface is id5tical ) t :i* reta9s ! moon 9 h] orbit2 & he conclud$1 t1 z ! moon is kept 9 h] orbit by ! attraction ( ! e>?1 s ! planets might be reta9$ 9 _! orbits by ! attraction ( ! sun4 ,by su* /eps he 0 l$ to ! discov]y ( "o ( ^? p[]s ) :i* ! ,creator has orda9$ t matt] %\ld reciprocally act ^u matt]4 ,physical a/ronomy is ! sci5ce :i* comp>es & id5tifies ! laws ( motion obs]v$ on e>? ) ! motions t take place 9 ! heav5s3 & :i* traces1 by an un9t]rupt$ *a9 ( d$uction f ! great pr9ciple t gov]ns ! univ]se1 ! revolutions & rotations ( ! planets1 & ! oscillations 7,n4 #d7 ( ! fluids at _! surfaces2 & :i* e/imates ! *anges ! sy/em has hi!rto und]gone1 or may h]eaft] exp]i5ce--*anges :i* require millions ( ye>s = _! accompli%m5t4 ,! accumulat$ ef=ts ( a/ronom]s1 f ! e>lie/ dawn ( civilization1 h be5 necess>y to e/abli% ! me*anical !ory ( a/ronomy4 ,! c\rses ( ! planets h be5 obs]v$ = ages1 ) a degree ( p]sev]ance t is a/oni%+1 if we consid] ! imp]fection & ev5 ! want ( in/rum5ts4 ,! real motions ( ! e>? h be5 sep>at$ f ! app>5t motions ( ! planets2 ! laws ( ! planet>y revolutions h be5 discov]$2 & ! discov]y ( ^! laws has l$ to ! k ( ! gravitation 7,n4 #e7 ( matt]4 ,on ! o!r h&1 desc5d+ f ! pr9ciple ( gravitation1 e motion 9 ! sol> sy/em has be5 s completely expla9$1 t ! laws ( any a/ronomical ph5om5a t may h]eaft] occur are already det]m9$4 ,,section ,i4 ,attraction ( a ,sph]e--,=m ( ,cele/ial ,bodies--,t]re/rial ,gravitation reta9s ! ,moon 9 h] ,orbit--,! ,heav5ly ,bodies move 9 ,conic ,sections--,gravitation ,proportional to ,mass--,gravitation ( ! ,p>ticles ( ,matt]--,figure ( ! ,planets--,h[ x affects ! ,motions ( _! ,satellites--,rotation & ,translation impress$ by ! same ,impulse--,motion ( ! ,sun & ,sol> ,sy/em4 ,,x has be5 prov$ by ,newton1 t a p>ticle ( matt] 7,n4 #f7 plac$ )\t ! surface ( a holl[ sph]e 7,n4 #g7 is attract$ by x 9 ! same mann] z if ! mass ( ! holl[ sph]e1 or ! :ole matt] x conta9s1 7 collect$ into "o d5se p>ticle 9 its c5tre4 ,! same is !re=e true ( a solid sph]e1 :i* may be suppos$ to consi/ ( an inf9ite numb] ( conc5tric holl[ sph]es 7,n4 #h74 ,?is1 h[ev]1 is n ! case ) a sph]oid 7,n4 #i72 b ! cele/ial bodies are s ne>ly sph]ical1 & at su* remote di/ances f "o ano!r1 t !y attract & are attract$ z if ea* 7 cond5s$ into a s+le p>ticle situate 9 its c5tre ( gravity 7,n4 #aj7--;a circum/ance :i* greatly facilitates ! inve/igation ( _! motions4 ,newton has %[n t ! =ce :i* reta9s ! moon 9 h] orbit is ! same ) t :i* causes heavy sub/ances to fall at ! surface ( ! e>?4 ,if ! e>? 7 a sph]e1 & at re/1 a body w\ld be equally attract$1 t is1 x w\ld h ! same weight at e po9t ( its surface1 because ! surface ( a sph]e is ev]y:]e equally di/ant f its c5tre4 ,b1 z our planet is flatt5$ at ! poles 7,n4 #aa71 & bulges at ! equator1 ! weight ( ! same body gradually decreases f ! poles1 :]e x is greate/1 to ! equator1 :]e x is lea/4 ,!re is1 h[ev]1 a c]ta9 mean 7,n4 #ab7 latitude 7,n4 #ac71 or "p ( ! e>? int]m$iate betwe5 ! pole & ! equator1 :]e ! attraction ( ! e>? on bodies at its surface is ! same z if x 7 a sph]e2 & exp]i5ce %[s t bodies !re fall ?r\gh #afjfig feet 9 a second4 ,! mean di/ance 7,n4 #ad7 ( ! moon f ! e>? is ab\t sixty times ! mean radius 7,n4 #ae7 ( ! e>?4 ,:5 ! numb] #afjfig is dim9i%$ 9 ! ratio 7,n4 #af7 ( #a to #cfjj1 :i* is ! squ>e ( ! moon's di/ance 7,n4 #ag7 f ! e>?'s c5tre1 e/imat$ 9 t]re/rial radii1 x is f\nd to be exactly ! space ! moon w\ld fall ?r\gh 9 ! fir/ second ( h] desc5t to ! e>?1 7 %e n prev5t$ by ! c5trifugal =ce 7,n4 #ah7 aris+ f ! velocity ) :i* %e moves 9 h] orbit4 ,! moon is ?us reta9$ 9 h] orbit by a =ce hav+ ! same orig91 & regulat$ by ! same law1 ) t :i* causes a /one to fall at ! e>?'s surface4 ,! e>? may1 !re=e1 be reg>d$ z ! c5tre ( a =ce :i* ext5ds to ! moon2 &1 z exp]i5ce %[s t ! action & reaction ( matt] are equal & contr>y 7,n4 #ai71 ! moon mu/ attract ! e>? ) an equal & contr>y =ce4 ,newton also asc]ta9$ t a body project$ 7,n4 #bj7 9 space 7,n4 #ba7 w move 9 a conic section 7,n4 #bb71 if attract$ by a =ce proce$+ f a fix$ po9t1 ) an int5sity inv]sely z ! squ>e ( ! di/ance 7,n4 #bc72 b t any deviation f t law w cause x to move 9 a curve ( a diff]5t nature4 ,kepl] f\nd1 by direct obs]vation1 t ! planets describe ellipses 7,n4 #bd71 or oval pa?s1 r\nd ! sun4 ,lat] obs]vations %[ t comets also move 9 conic sections4 ,x consequ5tly foll[s t ! sun attracts all ! planets & comets inv]sely z ! squ>e ( _! di/ances f its c5tre2 ! sun1 !re=e1 is ! c5tre ( a =ce ext5d+ indef9itely 9 space1 & includ+ all ! bodies ( ! sy/em 9 its action4 ,kepl] also d$uc$ f obs]vation t ! squ>es ( ! p]iodic times 7,n4 #be7 ( ! planets1 or ! times ( _! revolutions r\nd ! sun1 are proportional to ! cubes ( _! mean di/ances f its c5tre 7,n4 #bf74 ,h5ce ! int5sity ( gravitation ( all ! bodies t[>ds ! sun is ! same at equal di/ances4 ,consequ5tly1 gravitation is proportional to ! masses 7,n4 #bg72 =1 if ! planets & comets 7 at equal di/ances f ! sun1 & left to ! effects ( gravity1 !y w\ld arrive at 8 surface at ! same "t 7,n4 #bh74 ,! satellites also gravitate to _! prim>ies 7,n4 #bi7 accord+ to ! same law t _! prim>ies d to ! sun4 ,?us1 by ! law ( action & reaction1 ea* body is itself ! c5tre ( an attractive =ce ext5d+ indef9itely 9 space1 caus+ all ! mutual di/urbances :i* r5d] ! cele/ial motions s complicat$1 & _! inve/igation s difficult4 ,! gravitation ( matt] direct$ to a c5tre1 & attract+ directly z ! mass & inv]sely z ! squ>e ( ! di/ance1 does n belong to x :5 consid]$ 9 mass only2 p>ticle acts on p>ticle accord+ to ! same law :5 at s5sible di/ances f ea* o!r4 ,if ! sun act$ on ! c5tre ( ! e>?1 )\t attract+ ea* ( its p>ticles1 ! tides w\ld be v mu* great] ?an !y n[ are1 & w\ld also1 9 o!r respects1 be v diff]5t4 ,! gravitation ( ! e>? to ! sun results f ! gravitation ( all its p>ticles1 :i*1 9 _! turn1 attract ! sun 9 ! ratio ( _! respective masses4 ,!re is a reciprocal action likewise betwe5 ! e>? & e p>ticle at its surface4 ,! e>? & a fea!r mutually attract ea* o!r 9 ! proportion ( ! mass ( ! e>? to ! mass ( ! fea!r4 ,7 ?is n ! case1 & 7 any portion ( ! e>?1 h[ev] small1 to attract ano!r portion1 & n be itself attract$1 ! c5tre ( gravity ( ! e>? w\ld be mov$ 9 space by ?is action1 :i* is impossible4 ,! =ms ( ! planets result f ! reciprocal attraction ( _! compon5t p>ticles4 ,a deta*$ fluid mass1 if at re/1 w\ld assume ! =m ( a sph]e1 f ! reciprocal attraction ( its p>ticles4 ,b if ! mass revolve ab\t an axis1 x becomes flatt5$ at ! poles & bulges at ! equator 7,n4 #aa71 9 consequ5ce ( ! c5trifugal =ce aris+ f ! velocity ( rotation 7,n4 #cj72 = ! c5trifugal =ce dim9i%es ! gravity ( ! p>ticles at ! equator1 & equilibrium c only exi/ :]e ^! two =ces are balanc$ by an increase ( gravity4 ,!re=e1 z ! attractive =ce is ! same on all p>ticles at equal di/ances f ! c5tre ( a sph]e1 ! equatorial p>ticles w\ld rec$e f ! c5tre1 till _! increase 9 numb] balance ! c5trifugal =ce by _! attraction4 ,consequ5tly1 ! sph]e w\ld become an oblate or flatt5$ sph]oid1 & a fluid1 p>tially or entirely cov]+ a solid1 z ! ocean & atmosph]e cov] ! e>?1 mu/ assume t =m 9 ord] to rema9 9 equilibrio4 ,! surface ( ! sea is1 !re=e1 sph]oidal1 & ! surface ( ! e>? only deviates f t figure :]e x rises above or s9ks bel[ ! level ( ! sea4 ,b ! deviation is s small1 t x is unimportant :5 comp>$ ) ! magnitude ( ! e>?2 = ! mighty *a9 ( ! ,&es1 & ! yet m l(ty ,himalaya1 be> ab\t ! same proportion to ! e>? t a gra9 ( s& does to a globe ?ree feet 9 diamet]4 ,su* is ! =m ( ! e>? & planets4 ,! compression 7,n4 #ca7 or flatt5+ at _! poles is1 h[ev]1 s small1 t ev5 ,jupit]1 ^: rotation is ! mo/ rapid1 & !re=e ! mo/ elliptical ( ! planets1 may1 f 8 great di/ance1 be reg>d$ z sph]ical4 ,al?\gh ! planets attract ea* o!r z if !y 7 sph]es1 on acc\nt ( _! di/ances1 yet ! satellites 7,n4 #cb7 are ne> en\gh to be s5sibly affect$ 9 _! motions by ! =ms ( _! prim>ies4 ,! moon1 = example1 is s ne> ! e>?1 t ! reciprocal attraction betwe5 ea* ( h] p>ticles1 & ea* ( ! p>ticles 9 ! prom95t mass at ! t]re/rial equator1 occasions consid]able di/urbances 9 ! motions ( bo? bodies2 = ! action ( ! moon on ! matt] at ! e>?'s equator produces a nutation 7,n4 #cc7 9 ! axis 7,n4 #cd7 ( rotation1 & ! reaction ( t matt] on ! moon is ! cause ( a correspond+ nutation 9 ! lun> orbit 7,n4 #ce74 ,if a sph]e at re/ 9 space receive an impulse pass+ ?r\gh its c5tre ( gravity1 all its p>ts w move ) an equal velocity 9 a /raight l9e2 b1 if ! impulse does n pass ?r\gh ! c5tre ( gravity1 its p>ticles1 hav+ unequal velocities1 w h a rotatory or revolv+ motion1 at ! same "t t x is translat$ 7,n4 #cf7 9 space4 ,^! motions are indep5d5t ( "o ano!r2 s t a contr>y impulse1 pass+ ?r\gh its c5tre ( gravity1 w imp$e its progress1 )\t int]f]+ ) its rotation4 ,! sun rotates ab\t an axis1 & mod]n obs]vations %[ t an impulse 9 a contr>y direction has n be5 giv5 to 8 c5tre ( gravity1 = he moves 9 space1 accompani$ by all ^? bodies :i* compose ! sol> sy/em--a circum/ance :i* 9 no way int]f]es ) _! relative motions2 =1 9 consequ5ce ( ! pr9ciple t =ce is proportional to velocity 7,n4 #cg71 ! reciprocal attractions ( a sy/em rema9 ! same :e!r its c5tre ( gravity be at re/1 or mov+ uni=mly 9 space4 ,x is comput$ t1 _h ! e>? receiv$ its motion f a s+le impulse1 t impulse mu/ h pass$ ?r\gh a po9t ab\t tw5ty-five miles f its c5tre4 ,s9ce ! motions ( rotation & translation ( ! planets are indep5d5t ( ea* o!r1 ?\gh probably communicat$ by ! same impulse1 !y =m sep>ate subjects ( inve/igation4 ,,section ,,ii4 ,elliptical ,motion--,mean & ,true ,motion--,equ9octial--,ecliptic--,equ9ox es--,mean & ,true ,longitude--,equation ( ,c5tre--,incl9ation ( ! ,orbits ( ,planets--,cele/ial ,latitude--,nodes--,elem5ts ( an ,orbit--,undi/urb$ or ,elliptical ,orbits--,great ,incl9ation ( ! ,orbits ( ! ,new ,planets--,univ]sal ,gravitation ! ,cause ( ,p]turbations 9 ! ,motions ( ! ,heav5ly ,bodies--,problem ( ! ,?ree ,bodies--,/ability ( ,sol> ,sy/em dep5ds ^u ! ,primitive ,mom5tum ( ! ,bodies4 ,a ,,planet moves 9 its elliptical orbit ) a velocity v>y+ e in/ant1 9 consequ5ce ( two =ces1 "o t5d+ to ! c5tre ( ! sun1 & ! o!r 9 ! direction ( a tang5t 7,n4 #ch7 to its orbit1 aris+ f ! primitive impulse giv5 at ! "t :5 x 0 laun*$ into space4 ,%\ld ! =ce 9 ! tang5t cease1 ! planet w\ld fall to ! sun by its gravity4 ,7 ! sun n to attract x1 ! planet w\ld fly (f 9 ! tang5t4 ,?us1 :5 ! planet is at ! po9t ( its orbit f>!/ f ! sun1 8 action ov]comes ! planet's velocity1 & br+s x t[>ds him ) su* an accel]at$ motion1 t at la/ x ov]comes ! sun's attraction1 &1 %oot+ pa/ him1 gradually decreases 9 velocity until x arrives at ! mo/ di/ant po9t1 :]e ! sun's attraction aga9 prevails 7,n4 #ci74 ,9 ?is motion ! radii vectores 7,n4 #dj71 or imag9>y l9es jo9+ ! c5tres ( ! sun & ! planets1 pass ov] equal areas or spaces 9 equal times 7,n4 #da74 ,! mean di/ance ( a planet f ! sun is equal to half ! major axis 7,n4 #db7 ( its orbit3 if1 !re=e1 ! planet describ$ a circle 7,n4 #dc7 r\nd ! sun at its mean di/ance1 ! motion w\ld be uni=m1 & ! p]iodic "t unalt]$1 because ! planet w\ld arrive at ! extremities ( ! major axis at ! same in/ant1 & w\ld h ! same velocity1 :e!r x mov$ 9 ! circul> or elliptical orbit1 s9ce ! curves co9cide 9 ^! po9ts4 ,b 9 e o!r "p ! elliptical1 or true motion 7,n4 #dd71 w\ld ei!r be fa/] or sl[] ?an ! circul> or mean motion 7,n4 #de74 ,z x is necess>y to h "s fix$ po9t 9 ! heav5s f :5ce to e/imate ^! motions1 ! v]nal equ9ox 7,n4 #df7 at a giv5 epo* has be5 *os54 ,! equ9octial1 :i* is a great circle trac$ 9 ! />ry heav5s by ! imag9>y ext5sion ( ! plane ( ! t]re/rial equator1 is int]sect$ by ! ecliptic1 or app>5t pa? ( ! sun1 9 two po9ts diametrically opposite to "o ano!r1 call$ ! v]nal & autumnal equ9oxes4 ,! v]nal equ9ox is ! po9t ?r\gh :i* ! sun passes 9 go+ f ! s\!rn to ! nor!rn hemisph]e2 & ! autumnal1 t 9 :i* he crosses f ! nor!rn to ! s\!rn4 ,! mean or circul> motion ( a body1 e/imat$ f ! v]nal equ9ox1 is its mean longitude2 & its elliptical1 or true motion1 reckon$ f t po9t1 is its true longitude 7,n4 #dg73 bo? be+ e/imat$ f we/ to ea/1 ! direction 9 :i* ! bodies move4 ,! diff]5ce betwe5 ! two is call$ ! equation ( ! c5tre 7,n4 #dh72 :i* consequ5tly vani%es at ! apsides 7,n4 #di71 or extremities ( ! major axis1 & is at its maximum n9ety degrees 7,n4 #ej7 di/ant f ^! po9ts1 or 9 quadratures 7,n4 #ea71 :]e x measures ! exc5tricity 7,n4 #eb7 ( ! orbit2 s t ! place ( ! planet 9 its elliptical orbit is obta9$ by add+ or subtract+ ! equation ( ! c5tre to or f its mean longitude4 ,! orbits ( ! pr9cipal planets h a v small obliquity or incl9ation 7,n4 #ec7 to ! plane ( ! ecliptic 9 :i* ! e>? moves2 &1 on t acc\nt1 a/ronom]s ref] _! motions to ?is plane at a giv5 epo* z a kn[n & fix$ position4 ,! angul> di/ance ( a planet f ! plane ( ! ecliptic is its latitude 7,n4 #ed71 :i* is s\? or nor? accord+ z ! planet is s\? or nor? ( t plane4 ,:5 ! planet is 9 ! plane ( ! ecliptic1 its latitude is z]o2 x is !n said to be 9 its nodes 7,n4 #ee74 ,! asc5d+ node is t po9t 9 ! ecliptic ?r\gh :i* ! planet passes 9 go+ f ! s\!rn to ! nor!rn hemisph]e4 ,! desc5d+ node is a correspond+ po9t 9 ! plane ( ! ecliptic diametrically opposite to ! o!r1 ?r\gh :i* ! planet desc5ds 9 go+ f ! nor!rn to ! s\!rn hemisph]e4 ,! longitude & latitude ( a planet _c be obta9$ by direct obs]vation1 b are d$uc$ f obs]vations made at ! surface ( ! e>? by a v simple computation4 ,^! two quantities1 h[ev]1 w n give ! place ( a planet 9 space4 ,its di/ance f ! sun 7,n4 #ef7 mu/ also be kn[n2 &1 = ! complete det]m9ation ( its elliptical motion1 ! nature & position ( its orbit mu/ be asc]ta9$ by obs]vation4 ,?is dep5ds ^u sev5 quantities1 call$ ! elem5ts ( ! orbit 7,n4 #eg74 ,^! are1 ! l5g? ( ! major axis1 & ! exc5tricity1 :i* det]m9e ! =m ( ! orbit2 ! longitude ( ! planet :5 at its lea/ di/ance f ! sun1 call$ ! longitude ( ! p]ihelion2 ! incl9ation ( ! orbit to ! plane ( ! ecliptic1 & ! longitude ( its asc5d+ node3 ^! give ! position ( ! orbit 9 space2 b ! p]iodic "t1 & ! longitude ( ! planet at a giv5 in/ant1 call$ ! longitude ( ! epo*1 are necess>y = f9d+ ! place ( ! body 9 its orbit at all times4 ,a p]fect k ( ^! sev5 elem5ts is requisite = asc]ta9+ all ! circum/ances ( undi/urb$ elliptical motion4 ,by su* means x is f\nd t ! pa?s ( ! planets1 :5 _! mutual di/urbances are omitt$1 are ellipses ne>ly approa*+ to circles1 ^: planes1 slightly incl9$ to ! ecliptic1 cut x 9 /raight l9es1 pass+ ?r\gh ! c5tre ( ! sun 7,n4 #eh74 ,! orbits ( ! rec5tly-discov]$ planets deviate m f ! ecliptic ?an ^? ( ! anci5t planets3 t ( ,pallas1 = in/ance1 has an incl9ation ( #cd #db #bih to x2 on :i* acc\nt x is m difficult to det]m9e _! motions4 ,7 ! planets attract$ by ! sun only1 !y w\ld always move 9 ellipses1 inv>iable 9 =m & position2 & because 8 action is proportional to 8 mass1 :i* is mu* l>g] ?an t ( all ! planets put toge!r1 ! elliptical is ! ne>e/ approximation to _! true motions4 ,! true motions ( ! planets are extremely complicat$1 9 consequ5ce ( _! mutual attraction1 s t !y d n move 9 any kn[n or symmetrical curve1 b 9 pa?s n[ approa*+ to1 n[ rec$+ f1 ! elliptical =m2 & _! radii vectores d n describe areas or spaces exactly proportional to ! "t1 s t ! areas become a te/ ( di/urb+ =ces4 ,to det]m9e ! motion ( ea* body1 :5 di/urb$ by all ! re/1 is beyond ! p[] ( analysis4 ,x is !re=e necess>y to e/imate ! di/urb+ action ( "o planet at a "t1 :5ce ! celebrat$ problem ( ! ?ree bodies1 orig9ally appli$ to ! moon1 ! e>?1 & ! sun--namely1 ! masses be+ giv5 ( ?ree bodies project$ f ?ree giv5 po9ts1 ) velocities giv5 bo? 9 quantity & direction2 & suppos+ ! bodies to gravitate to "o ano!r ) =ces t are directly z _! masses1 & inv]sely z ! squ>es ( ! di/ances1 to f9d ! l9es describ$ by ^! bodies1 & _! positions at any giv5 in/ant2 or1 9 o!r words1 to det]m9e ! pa? ( a cele/ial body :5 attract$ by a second body1 & di/urb$ 9 its motion r\nd ! second body by a ?ird--a problem equally applicable to planets1 satellites1 & comets4 ,by ?is problem ! motions ( translation ( ! cele/ial bodies are det]m9$4 ,x is an extremely difficult "o1 & w\ld be inf9itely m s if ! di/urb+ action 7 n v small :5 comp>$ ) ! c5tral =ce2 t is1 if ! action ( ! planets on "o ano!r 7 n v small :5 comp>$ ) t ( ! sun4 ,z ! di/urb+ influ5ce ( ea* body may be f\nd sep>ately1 x is assum$ t ! action ( ! :ole sy/em1 9 di/urb+ any "o planet1 is equal to ! sum ( all ! p>ticul> di/urbances x exp]i5ces1 on ! g5]al me*anical pr9ciple1 t ! sum ( any numb] ( small oscillations is ne>ly equal to _! simultane\s & jo9t effect4 ,on acc\nt ( ! reciprocal action ( matt]1 ! /ability ( ! sy/em dep5ds ^u ! int5sity ( ! primitive mom5tum 7,n4 #ei7 ( ! planets1 & ! ratio ( _! masses to t ( ! sun2 = ! nature ( ! conic sections 9 :i* ! cele/ial bodies move dep5ds ^u ! velocity ) :i* !y 7 fir/ propell$ 9 space4 ,_h t velocity be5 su* z to make ! planets move 9 orbits ( un/able equilibrium 7,n4 #fj71 _! mutual attractions might h *ang$ !m into p>abolas1 or ev5 hyp]bolas 7,n4 #bb72 s t ! e>? & planets might1 ages ago1 h be5 sweep+ f> f our sun ?r\gh ! abyss ( space4 ,b z ! orbits diff] v little f circles1 ! mom5tum ( ! planets1 :5 project$1 mu/ h be5 exactly suffici5t to ensure ! p]man5cy & /ability ( ! sy/em4 ,besides1 ! mass ( ! sun is va/ly great] ?an t ( any planet2 & z _! inequalities be> ! same ratio to _! elliptical motions t _! masses d to t ( ! sun1 _! mutual di/urbances only increase or dim9i% ! exc5tricities ( _! orbits by v m9ute quantities2 consequ5tly ! magnitude ( ! sun's mass is ! pr9cipal cause ( ! /ability ( ! sy/em4 ,!re is n 9 ! physical _w a m spl5did example ( ! adaptation ( means to ! accompli%m5t ( an end ?an is exhibit$ 9 ! nice adju/m5t ( ^! =ces1 at once ! cause ( ! v>iety & ( ! ord] ( ,nature4 ,,section ,,iii4 ,p]turbations1 ,p]iodic & ,secul>--,di/urb+ ,action equival5t to ?ree ,p>tial ,=ces--,tang5tial ,=ce ! cause ( ! ,p]iodic ,inequalities 9 ,longitude1 & ,secul> ,inequalities 9 ! ,=m & ,position ( ! ,orbit 9 its own ,plane--,radial ,=ce ! cause ( ,v>iations 9 ! ,planet's ,di/ance f ! ,sun--,x comb9es ) ! ,tang5tial ,=ce to produce ! ,secul> ,v>iations 9 ! ,=m & ,position ( ! ,orbit 9 its own ,plane--,p]p5dicul> ,=ce ! cause ( ,p]iodic ,p]turbations 9 ,latitude1 & ,secul> ,v>iations 9 ! ,position ( ! ,orbit ) reg>d to ! ,plane ( ! ,ecliptic--,mean ,motion & ,major ,axis ,inv>iable--,/ability ( ,sy/em--,effects ( a ,resi/+ ,m$ium--,inv>iable ,plane ( ! ,sol> ,sy/em & ( ! ,univ]se--,great ,inequality ( ,jupit] & ,saturn4 ,,! planets are subject to di/urbances ( two k9ds1 bo? result+ f ! con/ant op]ation ( _! reciprocal attraction3 "o k9d1 dep5d+ ^u _! positions ) reg>d to ea* o!r1 beg9s f z]o1 increases to a maximum1 decreases1 & becomes z]o aga91 :5 ! planets return to ! same relative positions4 ,9 consequ5ce ( ^!1 ! di/urb$ planet is sometimes drawn away f ! sun1 sometimes br\ght ne>] to him3 sometimes x is accel]at$ 9 its motion1 & sometimes ret>d$4 ,at "o "t x is drawn above ! plane ( its orbit1 at ano!r "t bel[ x1 accord+ to ! position ( ! di/urb+ body4 ,all su* *anges1 be+ accompli%$ 9 %ort p]iods1 "s 9 a few mon?s1 o!rs 9 ye>s1 or 9 hundr$s ( ye>s1 are d5om9at$ p]iodic inequalities4 ,! inequalities ( ! o!r k9d1 ?\gh occasion$ likewise by ! di/urb+ en]gy ( ! planets1 are entirely indep5d5t ( _! relative positions4 ,!y dep5d ^u ! relative positions ( ! orbits alone1 ^: =ms & places 9 space are alt]$ by v m9ute quantities1 9 imm5se p]iods ( "t1 & are !re=e call$ secul> inequalities4 ,! p]iodical p]turbations are comp5sat$ :5 ! bodies return to ! same relative positions ) reg>d to "o ano!r & to ! sun3 ! secul> inequalities are comp5sat$ :5 ! orbits return to ! same positions relatively to "o ano!r & to ! plane ( ! ecliptic4 ,planet>y motion1 includ+ bo? ^! k9ds ( di/urbance1 may be repres5t$ by a body revolv+ 9 an ellipse1 & mak+ small & transi5t deviations1 n[ on "o side ( its pa?1 & n[ on ! o!r1 :il/ ! ellipse itself is sl[ly1 b p]petually1 *ang+ bo? 9 =m & position4 ,! p]iodic inequalities are m]ely transi5t deviations ( a planet f its pa?1 ! mo/ rem>kable ( :i* only la/s ab\t #iah ye>s2 b1 9 consequ5ce ( ! secul> di/urbances1 ! apsides1 or extremities ( ! major axes ( all ! orbits1 h a direct b v>iable motion 9 space1 except+ ^? ( ! orbit ( ,v5us1 :i* are retrograde 7,n4 #fa71 & ! l9es ( ! nodes move ) a v>iable velocity 9 a contr>y direction4 ,besides ^!1 ! incl9ation & exc5tricity ( e orbit are 9 a /ate ( p]petual b sl[ *ange4 ,^! effects result f ! di/urb+ action ( all ! planets on ea*4 ,b1 z x is only necess>y to e/imate ! di/urb+ influ5ce ( "o body at a "t1 :at foll[s may convey "s idea ( ! mann] 9 :i* "o planet di/urbs ! elliptical motion ( ano!r4 ,suppose two planets mov+ 9 ellipses r\nd ! sun2 if "o ( !m attract$ ! o!r & ! sun ) equal int5sity1 & 9 p>allel directions 7,n4 #fb71 x w\ld h no effect 9 di/urb+ ! elliptical motion4 ,! inequality ( ?is attraction is ! sole cause ( p]turbation1 & ! diff]5ce betwe5 ! di/urb+ planet's action on ! sun & on ! di/urb$ planet con/itutes ! di/urb+ =ce1 :i* consequ5tly v>ies 9 int5sity & direction ) e *ange 9 ! relative positions ( ! ?ree bodies4 ,al?\gh bo? ! sun & planet are "u ! influ5ce ( ! di/urb+ =ce1 ! motion ( ! di/urb$ planet is ref]r$ to ! c5tre ( ! sun z a fix$ po9t1 = conv5i5ce4 ,! :ole =ce 7,n4 #fc7 :i* di/urbs a planet is equival5t to ?ree p>tial =ces4 ,"o ( ^! acts on ! di/urb$ planet1 9 ! direction ( a tang5t to its orbit1 & is call$ ! tang5tial =ce3 x occasions secul> inequalities 9 ! =m & position ( ! orbit 9 its own plane1 & is ! sole cause ( ! p]iodical p]turbations 9 ! planet's longitude4 ,ano!r acts ^u ! same body 9 ! direction ( its radius vector1 t is1 9 ! l9e jo9+ ! c5tres ( ! sun & planet1 & is call$ ! radial =ce3 x produces p]iodical *anges 9 ! di/ance ( ! planet f ! sun1 & affects ! =m & position ( ! orbit 9 its own plane4 ,! ?ird1 :i* may be call$ ! p]p5dicul> =ce1 acts at "r angles to ! plane ( ! orbit1 occasions ! p]iodic inequalities 9 ! planet's latitude1 & affects ! position ( ! orbit ) reg>d to ! plane ( ! ecliptic4 ,x has be5 obs]v$1 t ! radius vector ( a planet1 mov+ 9 a p]fectly elliptical orbit1 passes ov] equal spaces or areas 9 equal times2 a circum/ance :i* is indep5d5t ( ! law ( ! =ce1 & w\ld be ! same :e!r x v>i$ inv]sely z ! squ>e ( ! di/ance1 or n1 provid$ only t x be direct$ to ! c5tre ( ! sun4 ,h5ce ! tang5tial =ce1 n be+ direct$ to ! c5tre1 occasions an unequable description ( areas1 or1 :at is ! same ?+1 x di/urbs ! motion ( ! planet 9 longitude4 ,! tang5tial =ce sometimes accel]ates ! planet's motion1 sometimes ret>ds x1 & occasionally has no effect at all4 ,7 ! orbits ( bo? planets circul>1 a complete comp5sation w\ld take place at ea* revolution ( ! two planets1 because ! arcs 9 :i* ! accel]ations & ret>dations take place w\ld be symmetrical on ea* side ( ! di/urb+ =ce4 ,= x is cle>1 t if ! motion be accel]at$ ?r\gh a c]ta9 space1 & !n ret>d$ ?r\gh z mu*1 ! motion at ! end ( ! "t w be ! same z if no *ange _h tak5 place4 ,b1 z ! orbits ( ! planets are ellipses1 ?is symmetry does n hold3 =1 z ! planet moves unequably 9 its orbit1 x is 9 "s positions m directly1 & = a long] "t1 "u ! influ5ce ( ! di/urb+ =ce ?an 9 o!rs4 ,&1 al?\gh multitudes ( v>iations d comp5sate ea* o!r 9 %ort p]iods1 !re are o!rs1 dep5d+ on peculi> relations among ! p]iodic times ( ! planets1 :i* d n comp5sate ea* o!r till aft] "o1 or ev5 till aft] _m revolutions ( bo? bodies4 ,a p]iodical inequality ( ?is k9d 9 ! motions ( ,jupit] & ,saturn has a p]iod ( no less ?an #iah ye>s4 ,! radial =ce1 or t "p ( ! di/urb+ =ce :i* acts 9 ! direction ( ! l9e jo9+ ! c5tres ( ! sun & di/urb$ planet1 has no effect on ! areas1 b is ! cause ( p]iodical *anges ( small ext5t 9 ! di/ance ( ! planet f ! sun4 ,x has already be5 %[n1 t ! =ce produc+ p]fectly elliptical motion v>ies inv]sely z ! squ>e ( ! di/ance1 & t a =ce foll[+ any o!r law w\ld cause ! body to move 9 a curve ( a v diff]5t k9d4 ,n[1 ! radial di/urb+ =ce v>ies directly z ! di/ance2 &1 z x sometimes comb9es ) & increases ! int5sity ( ! sun's attraction = ! di/urb$ body1 & at o!r times opposes & consequ5tly dim9i%es x1 9 bo? cases x causes ! sun's attraction to deviate f ! exact law ( gravity1 & ! :ole action ( ?is comp\nd c5tral =ce on ! di/urb$ body is ei!r great] or less ?an :at is requisite = p]fectly elliptical motion4 ,:5 great]1 ! curvature ( ! di/urb$ planet's pa?1 on leav+ its p]ihelion 7,n4 #fd71 or po9t ne>e/ ! sun1 is great] ?an x w\ld be 9 ! ellipse1 :i* br+s ! planet to its aphelion 7,n4 #fe71 or po9t f>!/ f ! sun1 be=e x has pass$ ?r\gh #ahj1 z x w\ld d if undi/urb$4 ,s t 9 ?is case ! apsides1 or extremities ( ! major axis1 advance 9 space4 ,:5 ! c5tral =ce is less ?an ! law ( gravity requires1 ! curvature ( ! planet's pa? is less ?an ! curvature ( ! ellipse4 ,s t ! planet1 on leav+ its p]ihelion1 w\ld pass ?r\gh m ?an #ahj be=e arriv+ at its aphelion1 :i* causes ! apsides to rec$e 9 space 7,n4 #ff74 ,cases bo? ( advance & recess occur dur+ a revolution ( ! two planets2 b ^? 9 :i* ! apsides advance prepond]ate4 ,?is1 h[ev]1 is n ! full am\nt ( ! motion ( ! apsides2 "p arises also f ! tang5tial =ce 7,n4 #fc71 :i* alt]nately accel]ates & ret>ds ! velocity ( ! di/urb$ planet4 ,an increase 9 ! planet's tang5tial velocity dim9i%es ! curvature ( its orbit1 & is equival5t to a decrease ( c5tral =ce4 ,on ! contr>y1 a decrease ( ! tang5tial velocity1 :i* increases ! curvature ( ! orbit1 is equival5t to an increase ( c5tral =ce4 ,^! fluctuations1 ow+ to ! tang5tial =ce1 occasion an alt]nate recess & advance ( ! apsides1 aft] ! mann] already expla9$ 7,n4 #ff74 ,an uncomp5sat$ portion ( ! direct motion1 aris+ f ?is cause1 conspires ) t already impress$ by ! radial =ce1 & 9 "s cases ev5 ne>ly d\bles ! direct motion ( ^! po9ts4 ,! motion ( ! apsides may be repres5t$ by suppos+ a planet to move 9 an ellipse1 :ile ! ellipse itself is sl[ly revolv+ ab\t ! sun 9 ! same plane 7,n4 #fg74 ,?is motion ( ! major axis1 :i* is direct 9 all ! orbits except t ( ! planet ,v5us1 is irregul>1 & s sl[ t x requires m ?an #aji1hcj ye>s = ! major axis ( ! e>?'s orbit to accompli% a sid]eal revolution 7,n4 #fh71 t is1 to return to ! same />s2 & #bj1ihd ye>s to complete its tropical revolution 7,n4 #fi71 or to return to ! same equ9ox4 ,! diff]5ce betwe5 ^! two p]iods arises f a retrograde motion 9 ! equ9octial po9t1 :i* meets ! advanc+ axis be=e x has complet$ its revolution ) reg>d to ! />s4 ,! major axis ( ,jupit]'s orbit requires no less ?an #bjj1faj ye>s to p]=m its sid]eal revolution1 & #bb1gdh ye>s to accompli% its tropical revolution f ! di/urb+ action ( ,saturn alone4 ,a v>iation 9 ! exc5tricity ( ! di/urb$ planet's orbit is an imm$iate consequ5ce ( ! deviation f elliptical curvature1 caus$ by ! action ( ! di/urb+ =ce4 ,:5 ! pa? ( ! body1 9 proce$+ f its p]ihelion to its aphelion1 is m curv$ ?an x ought to be f ! effect ( ! di/urb+ =ces1 x falls )9 ! elliptical orbit1 ! exc5tricity is dim9i%$1 & ! orbit becomes m ne>ly circul>2 :5 t curvature is less ?an x ought to be1 ! pa? ( ! planet falls )\t its elliptical orbit 7,n4 #ff71 & ! exc5tricity is increas$2 dur+ ^! *anges1 ! l5g? ( ! major axis is n alt]$1 ! orbit only bulges out1 or becomes m flat 7,n4 #gj74 ,?us ! v>iation 9 ! exc5tricity arises f ! same cause t occasions ! motion ( ! apsides 7,n4 #fg74 ,!re is an insep>able connection betwe5 ^! two elem5ts3 !y v>y simultane\sly1 & h ! same p]iod2 s t1 :il/ ! major axis revolves 9 an imm5se p]iod ( "t1 ! exc5tricity increases & decreases by v small quantities1 & at l5g? returns to its orig9al magnitude at ea* revolution ( ! apsides4 ,! t]re/rial exc5tricity is decreas+ at ! rate ( ab\t #dj miles annually2 &1 if x 7 to decrease equably1 x w\ld be #ci1hfa ye>s be=e ! e>?'s orbit became a circle4 ,! mutual action ( ,jupit] & ,saturn occasions v>iations 9 ! exc5tricity ( bo? orbits1 ! greate/ exc5tricity ( ,jupit]'s orbit correspond+ to ! lea/ ( ,saturn's4 ,! p]iod 9 :i* ^! vicissitudes are accompli%$ is #gj1dad ye>s1 e/imat+ ! action ( ^! two planets alone2 b1 if ! action ( all ! planets 7 e/imat$1 ! cycle w\ld ext5d to millions ( ye>s4 ,t "p ( ! di/urb+ =ce is n[ to be consid]$ :i* acts p]p5dicul>ly to ! plane ( ! orbit1 caus+ p]iodic p]turbations 9 latitude1 secul> v>iations 9 ! incl9ation ( ! orbit1 & a retrograde motion to its nodes on ! true plane ( ! ecliptic 7,n4 #ga74 ,?is =ce t5ds to pull ! di/urb$ body above1 or pu% 7,n4 #gb7 x bel[1 ! plane ( its orbit1 accord+ to ! relative positions ( ! two planets ) reg>d to ! sun1 consid]$ to be fix$4 ,by ?is action1 x sometimes makes ! plane ( ! orbit ( ! di/urb$ body t5d to co9cide ) ! plane ( ! ecliptic1 & sometimes increases its incl9ation to t plane4 ,9 consequ5ce ( :i*1 its nodes alt]nately rec$e or advance on ! ecliptic 7,n4 #gc74 ,:5 ! di/urb+ planet is 9 ! l9e ( ! di/urb$ planet's nodes 7,n4 #gd71 x nei!r affects ^! po9ts1 ! latitude1 nor ! incl9ation1 because bo? planets are !n 9 ! same plane4 ,:5 x is at "r angles to ! l9e ( ! nodes1 & ! orbit symmetrical on ea* side ( ! di/urb+ =ce1 ! av]age motion ( ^! po9ts1 aft] a revolution ( ! di/urb$ body1 is retrograde1 & comp>atively rapid3 b1 :5 ! di/urb+ planet is s situat$ t ! orbit ( ! di/urb$ planet is n symmetrical on ea* side ( ! di/urb+ =ce1 :i* is mo/ frequ5tly ! case1 e possible v>iety ( action takes place4 ,consequ5tly1 ! nodes are p]petually advanc+ or rec$+ ) unequal velocity2 b1 z a comp5sation is n effect$1 _! motion is1 on ! :ole1 retrograde4 ,) reg>d to ! v>iations 9 ! incl9ation1 x is cle>1 t1 :5 ! orbit is symmetrical on ea* side ( ! di/urb+ =ce1 all its v>iations are comp5sat$ aft] a revolution ( ! di/urb$ body1 & are m]ely p]iodical p]turbations 9 ! planet's latitude2 & no secul> *ange is induc$ 9 ! incl9ation ( ! orbit4 ,:51 on ! contr>y1 t orbit is n symmetrical on ea* side ( ! di/urb+ =ce1 al?\gh _m ( ! v>iations 9 latitude are transi5t or p]iodical1 /ill1 aft] a complete revolution ( ! di/urb$ body1 a portion rema9s uncomp5sat$1 :i* =ms a secul> *ange 9 ! incl9ation ( ! orbit to ! plane ( ! ecliptic4 ,x is true1 "p ( ?is secul> *ange 9 ! incl9ation is comp5sat$ by ! revolution ( ! di/urb+ body1 ^: motion has n hi!rto be5 tak5 into ! acc\nt1 s t p]turbation comp5sates p]turbation2 b /ill a comp>atively p]man5t *ange is effect$ 9 ! incl9ation1 :i* is n comp5sat$ till ! nodes h accompli%$ a complete revolution4 ,! *anges 9 ! incl9ation are extremely m9ute 7,n4 #ge71 comp>$ ) ! motion ( ! nodes1 & !re is ! same k9d ( insep>able connection betwe5 _! secul> *anges t !re is betwe5 ! v>iation ( ! exc5tricity & ! motion ( ! major axis4 ,! nodes & incl9ations v>y simultane\sly2 _! p]iods are ! same1 & v great4 ,! nodes ( ,jupit]'s orbit1 f ! action ( ,saturn alone1 require #cf1bfa ye>s to accompli% ev5 a tropical revolution4 ,9 :at prec$es1 ! influ5ce ( only "o di/urb+ body has be5 consid]$2 b1 :5 ! action & reaction ( ! :ole sy/em are tak5 into acc\nt1 e planet is act$ ^u1 & does itself act1 9 ?is mann]1 on all ! o!rs2 & ! jo9t effect keeps ! incl9ations & exc5tricities 9 a /ate ( p]petual v>iation4 ,x makes ! major axes ( all ! orbits cont9ually revolve1 & causes1 on an av]age1 a retrograde motion ( ! nodes ( ea* orbit ^u e o!r4 ,! ecliptic 7,n4 #ga7 itself is 9 motion f ! mutual action ( ! e>? & planets1 s t ! :ole is a comp\nd ph5om5on ( great complexity1 ext5d+ ?r\gh unkn[n ages4 ,at ! pres5t "t ! incl9ations ( all ! orbits are decreas+1 b s sl[ly1 t ! incl9ation ( ,jupit]'s orbit is only ab\t six m9utes less ?an x 0 9 ! age ( ,ptolemy4 ,b1 9 ! mid/ ( all ^! vicissitudes1 ! l5g? ( ! major axes & ! mean motions ( ! planets rema9 p]man5tly indep5d5t ( secul> *anges4 ,!y are s connect$ by ,kepl]'s law1 ( ! squ>es ( ! p]iodic times be+ proportional to ! cubes ( ! mean di/ances ( ! planets f ! sun1 t "o _c v>y )\t affect+ ! o!r4 ,& x is prov$1 t any v>iations :i* d take place are transi5t1 & dep5d only on ! relative positions ( ! bodies4 ,x is true t1 accord+ to !ory1 ! radial di/urb+ =ce %\ld p]man5tly alt] ! dim5sions ( all ! orbits1 & ! p]iodic times ( all ! planets1 to a c]ta9 degree4 ,= example1 ! masses ( all ! planets revolv+ )9 ! orbit ( any "o1 su* z ,m>s1 by add+ to ! int]ior mass1 increase ! attract+ =ce ( ! sun1 :i*1 !re=e1 mu/ contract ! dim5sions ( ! orbit ( t planet1 & dim9i% its p]iodic "t2 :il/ ! planets ext]ior to ,m>s's orbit mu/ h ! contr>y effect4 ,b ! mass ( ! :ole ( ! planets & satellites tak5 toge!r is s small1 :5 comp>$ ) t ( ! sun1 t ^! effects are q ins5sible1 & c\ld only h be5 discov]$ by !ory4 ,&1 z x is c]ta9 t ! l5g? ( ! major axes & ! mean motions are n p]man5tly *ang$ by any o!r p[] :atev]1 x may be conclud$ t !y are inv>iable4 ,) ! exception ( ^! two elem5ts1 x appe>s t all ! bodies are 9 motion1 & e orbit 9 a /ate ( p]petual *ange4 ,m9ute z ^! *anges are1 !y might be suppos$ to accumulate 9 ! c\rse ( ages1 suffici5tly to d]ange ! :ole ord] ( nature1 to alt] ! relative positions ( ! planets1 to put an end to ! vicissitudes ( ! seasons1 & to br+ ab\t collisions :i* w\ld involve our :ole sy/em1 n[ s h>moni\s1 9 *aotic confusion4 ,x is natural to inquire1 :at pro( exi/s t nature w be pres]v$ f su* a cata/rophe8 ,no?+ c be kn[n f obs]vation1 s9ce ! exi/5ce ( ! human race has occupi$ comp>atively b a po9t 9 duration1 :ile ^! vicissitudes embrace myriads ( ages4 ,! pro( is simple & conclusive4 ,all ! v>iations ( ! sol> sy/em1 secul> z well z p]iodic1 are express$ analytically by ! s9es & cos9es ( circul> arcs 7,n4 #gf71 :i* increase ) ! "t2 &1 z a s9e or cos9e c nev] exce$ ! radius1 b mu/ oscillate betwe5 z]o & unity1 h[ev] mu* ! "t may increase1 x foll[s t :5 ! v>iations h accumulat$ to a maximum by sl[ *anges1 9 h[ev] long a "t1 !y decrease1 by ! same sl[ degrees1 till !y arrive at _! smalle/ value1 aga9 to beg9 a new c\rse2 ?us = ev] oscillat+ ab\t a mean value4 ,?is circum/ance1 h[ev]1 w\ld be insuffici5t1 7 x n = ! small exc5tricities ( ! planet>y orbits1 _! m9ute incl9ations to ! plane ( ! ecliptic1 & ! revolutions ( all ! bodies1 z well planets z satellites1 9 ! same direction4 ,^! secure ! p]petual /ability ( ! sol> sy/em 7,n4 #gg74 ,h[ev]1 at ! "t t ! /ability 0 prov$ by ,la ,grange & ,la ,place1 ! telescopic planets betwe5 ,m>s & ,jupit] _h n be5 discov]$2 b ,la ,grange1 hav+ inve/igat$ ! subject "u a v g5]al po9t ( view1 %[$ t1 if a planet>y sy/em be compos$ ( v unequal masses1 ! :ole ( ! l>g] w\ld ma9ta9 an unalt]able /ability ) reg>d to ! =m & position ( _! orbits1 :ile ! orbits ( ! less] might und]go unlimit$ *anges4 ,m4 ,le ,v]ri] has appli$ ?is to ! sol> sy/em1 & has f\nd t ! orbits ( all ! l>g] planets w = ev] ma9ta9 an unalt]able /ability 9 =m & position2 =1 ?\gh liable to mutations ( v long p]iods1 !y return aga9 exactly to :at !y orig9ally 71 oscillat+ betwe5 v n>r[ limits2 b he f\nd a zone ( in/ability betwe5 ! orbit ( ,m>s1 & twice ! mean di/ance ( ! e>? f ! sun1#a or betwe5 #ae & #bjj2 !re=e ! position & =m ( ! orbits ( su* ( ! telescopic planets z revolve )9 t zone w be subject to unlimit$ v>iations4 ,b ! orbits ( ^? m remote f ! sun ?an ,flora1 or beyond #bbj1 w be /able1 s t _! exc5tricities & incl9ations mu/ always h be51 & w always rema91 v great1 s9ce !y mu/ h dep5d$ ^u ! primitive conditions t prevail$ :5 ^! planet>y atoms 7 laun*$ into space4 ,! #ea/ ( ^! small bodies1 :i* 0 discov]$1 & ! elem5ts ( its orbit det]m9$1 by ,m4 ,valz1 at ,nimes1 has a mean di/ance ( #ahh2 s x revolves )9 ! zone ( in/ability4 ,x has a %ort] p]iodic "t ?an any ( ^? previ\sly discov]$1 & a great] exc5tricity1 ) ! exception ( ,nysa4 ,its orbit cuts t ( ,m>s1 & comes ne>] to ! e>? ?an ! orbits ( ei!r ,m>s or ,v5us1 a circum/ance :i* w\ld be fav\rable = correct+ ! p>allax ( ! sun1 or confirm+ its accuracy4 ,! telescopic planets1 num]\s z !y are1 h no influ5ce on ! motions ( ! l>g] planets1 = ,jupit] has a diamet] ( #ij1gcd miles1 :ile t ( ,pallas1 8 ne>e/ neighb\r1 is only #ig miles1 little m ?an ! di/ance f ,london to ,ba?4 ,! diamet] ( ,m>s1 on ! o!r side ( ! small planets1 is #dedf miles1 & t ( ! e>? #gibe-a_/b miles1 s t ! telescopic gr\p are too m9ute to di/urb ! o!rs4 ,m4 ,le ,v]ri] f\nd ano!r zone ( in/ability betwe5 ,v5us & ! sun1 on ! bord] ( :i* ,m]cury is revolv+1 ! incl9ation ( ^: orbit to ! plane ( ! ecliptic is ab\t #g1 :i* is m ?an t ( any ( ! l>ge planets4 ,neptune's orbit is1 no d\bt1 z /able z t ( any o!r ( ! l>ge planets1 z ! incl9ation is v small1 b he w h p]iodical v>iations ( v long duration f ! reciprocal attraction betwe5 him & ,uranus1 "o especially ( an enorm\s duration1 simil> to ^? ( ,jupit] & ,saturn1 &1 l !m1 dep5d+ on ! "t ( 8 revolution r\nd ! sun1 be+ ne>ly twice z long z t ( ,saturn4 ,mr4 ,adams has comput$ t ,neptune produces a p]iodical p]turbation 9 ! motion ( ,uranus1 ^: duration is ab\t #fhjj ye>s4 ,! equilibrium ( ! sy/em1 h[ev]1 w\ld be d]ang$ if ! planets mov$ 9 a resi/+ m$ium 7,n4 #gh7 suffici5tly d5se to dim9i% _! tang5tial velocity1 = !n bo? ! exc5tricities & ! major axes ( ! orbits w\ld v>y ) ! "t1 s t ! /ability ( ! sy/em w\ld be ultimately de/roy$4 ,! exi/5ce ( an e!real m$ium is n[ prov$2 &1 al?\gh x is s extremely r>e t hi!rto its effects on ! motions ( ! planets h be5 altoge!r ins5sible1 !re c be no d\bt t1 9 ! imm5sity ( "t1 x w modify ! =ms ( ! planet>y orbits1 & may at la/ ev5 cause ! de/ruction ( our sy/em1 :i* 9 itself conta9s no pr9ciple ( decay1 unless a rotatory motion f we/ to ea/ has be5 giv5 to ?is m$ium by ! bodies ( ! sol> sy/em1 :i* h all be5 revolv+ ab\t ! sun 9 t direction = unkn[n ages4 ,?is rotation1 :i* seems to be highly probable1 may ev5 h be5 coeval ) its creation4 ,su* a vortex w\ld h no effect on bodies mov+ ) x1 b x w\ld influ5ce ! motions ( ^? revolv+ 9 a contr>y direction4 ,x is possible t ! di/urbances exp]i5c$ by comets1 :i* h already reveal$ ! exi/5ce ( ?is m$ium1 may also1 9 "t1 disclose its rotatory motion4 ,! =m & position ( ! planet>y orbits1 & ! motion ( ! bodies 9 ! same direction1 toge!r ) ! p]iodicity ( ! t]ms 9 :i* ! inequalities are express$1 assure u t ! v>iations ( ! sy/em are conf9$ )9 v n>r[ limits1 & t1 al?\gh we d n "k ! ext5t ( ! limits1 nor ! p]iod ( t gr& cycle :i* probably embraces millions ( ye>s1 yet !y nev] w exce$ :at is requisite = ! /ability & h>mony ( ! :ole2 = ! pres]vation ( :i* e circum/ance is s beautifully & wond]fully adapt$4 ,! plane ( ! ecliptic itself1 ?\gh assum$ to be fix$ at a giv5 epo* = ! conv5i5ce ( a/ronomical computation1 is subject to a m9ute secul> v>iation ( #deg1 occasion$ by ! reciprocal action ( ! planets4 ,b1 z ?is is also p]iodical1 & _c exce$ #b #db1 ! t]re/rial equator1 :i* is incl9$ to x at an angle#b ( #bc #bg #bhbi1 w nev] co9cide ) ! plane ( ! ecliptic3 s !re nev] c be p]petual spr+ 7,n4 #gi74 ,! rotation ( ! e>? is uni=m2 !re=e day & night1 summ] & w9t]1 w cont9ue _! vicissitudes :ile ! sy/em endures1 or is undi/urb$ by =eign causes4 ,yond] />ry sph]e ,( planets & ( fix'd1 9 all h] :eels1 ,resembles ne>e/ mazes intricate1 ,ecc5tric1 int]volv$1 yet regul>1 ,!n mo/1 :5 mo/ irregul> !y seem4 ,! /ability ( our sy/em 0 e/abli%$ by ,la ,grange3 8a discov]y10 says ,pr(essor ,playfair1 8t mu/ r5d] ! "n = ev] memorable 9 sci5ce1 & rev]$ by ^? :o delight 9 ! contemplation ( :atev] is excell5t & sublime40 ,aft] ,newton's discov]y ( ! me*anical laws ( ! elliptical orbits ( ! planets1 t ( _! p]iodical inequalities1 by ,la ,grange1 is1 )\t d\bt1 ! noble/ tru? 9 ! me*anism ( ! heav5s2 &1 9 respect ( ! doctr9e ( f9al causes1 x may be reg>d$ z ! greate/ ( all4 ,not)/&+ ! p]man5cy ( our sy/em1 ! secul> v>iations 9 ! planet>y orbits w\ld h be5 extremely emb>rass+ to a/ronom]s :5 x became necess>y to comp>e obs]vations sep>at$ by long p]iods4 ,! difficulty 0 9 "p obviat$1 & ! pr9ciple = accompli%+ x e/abli%$1 by ,la ,place1 & has s9ce be5 ext5d$ by ,m4 ,po9sot4 ,x appe>s t !re exi/s an inv>iable plane 7,n4 #hj71 pass+ ?r\gh ! c5tre ( gravity ( ! sy/em1 ab\t :i* ! :ole oscillates )9 v n>r[ limits1 & t ?is plane w always rema9 p>allel to itself1 :atev] *anges "t may induce 9 ! orbits ( ! planets1 9 ! plane ( ! ecliptic1 or ev5 9 ! law ( gravitation2 provid$ only t our sy/em rema9s unconnect$ ) any o!r4 ,! position ( ! plane is det]m9$ by ?is prop]ty--t1 if ea* p>ticle 9 ! sy/em be multipli$ by ! area describ$ ^u ?is plane 9 a giv5 "t1 by ! projection ( its radius vector ab\t ! common c5tre ( gravity ( ! :ole1 ! sum ( all ^! products w be a maximum 7,n4 #ha74 ,la ,place f\nd t ! plane 9 "q is incl9$ to ! ecliptic at an angle ( ne>ly #a #cd #ae1 & t1 9 pass+ ?r\gh ! sun1 & ab\t midway betwe5 ! orbits ( ,jupit] & ,saturn1 x may be reg>d$ z ! equator ( ! sol> sy/em1 divid+ x into two p>ts1 :i* balance "o ano!r 9 all _! motions4 ,?is plane ( greate/ in]tia1 by no means peculi> to ! sol> sy/em1 b exi/+ 9 e sy/em ( bodies submitt$ to _! mutual attractions only1 always ma9ta9s a fix$ position1 :5ce ! oscillations ( ! sy/em may be e/imat$ ?r\gh unlimit$ "t4 ,future a/ronom]s w "k1 f its immutability or v>iation1 :e!r ! sun & 8 att5dants are connect$ or n ) ! o!r sy/ems ( ! univ]se4 ,%\ld !re be no l9k betwe5 !m1 x may be inf]r$1 f ! rotation ( ! sun1 t ! c5tre ( gravity 7,n4 #hb7 ( ! sy/em situate )9 8 mass describes a /raight l9e 9 ?is inv>iable plane or great equator ( ! sol> sy/em1 :i*1 unaffect$ by ! *anges ( "t1 w ma9ta9 its /ability ?r\gh endless ages4 ,b1 if ! fix$ />s1 comets1 or any unkn[n & unse5 bodies1 affect our sun & planets1 ! nodes ( ?is plane w sl[ly rec$e on ! plane ( t imm5se orbit :i* ! sun may describe ab\t "s mo/ di/ant c5tre1 9 a p]iod :i* x transc5ds ! p[] ( man to det]m9e4 ,!re is e reason to believe t ?is is ! case2 = x is m ?an probable t1 remote z ! fix$ />s are1 !y 9 "s degree influ5ce our sy/em1 & t ev5 ! inv>iability ( ?is plane is relative1 only appe>+ fix$ to creatures incapable ( e/imat+ its m9ute & sl[ *anges dur+ ! small ext5t ( "t & space grant$ to ! human race4 8,! developm5t ( su* *anges10 z ,m4 ,po9sot ju/ly obs]ves1 8is simil> to an enorm\s curve1 ( :i* we see s small an arc t we imag9e x to be a /raight l9e40 ,if we raise our views to ! :ole ext5t ( ! univ]se1 & consid] ! />s1 toge!r ) ! sun1 to be w&]+ bodies1 revolv+ ab\t ! common c5tre ( creation1 we may !n recognise 9 ! equatorial plane pass+ ?r\gh ! c5tre ( gravity ( ! univ]se ! only in/ance ( absolute & et]nal repose4 ,all ! p]iodic & secul> inequalities d$uc$ f ! law ( gravitation are s p]fectly confirm$ by obs]vation1 t analysis has become "o ( ! mo/ c]ta9 means ( discov]+ ! planet>y irregul>ities1 ei!r :5 !y are too small1 or too long 9 _! p]iods1 to be detect$ by o!r me?ods4 ,jupit] & ,saturn1 h[ev]1 exhibit inequalities :i* = a long "t seem$ discordant ) t law4 ,all obs]vations1 f ^? ( ! ,*9ese & ,arabs d[n to ! pres5t day1 prove t = ages ! mean motions ( ,jupit] & ,saturn h be5 affect$ by a great inequality ( a v long p]iod1 =m+ an app>5t anomaly 9 ! !ory ( ! planets4 ,x 0 long kn[n by obs]vation t five times ! mean motion ( ,saturn is ne>ly equal to twice t ( ,jupit]2 a relation :i* ! sagacity ( ,la ,place p]ceiv$ to be ! cause ( a p]iodic irregul>ity 9 ! mean motion ( ea* ( ^! planets1 :i* completes its p]iod 9 ne>ly #iah ye>s1 ! "o be+ ret>d$ :ile ! o!r is accel]at$2 b bo? ! magnitude & p]iod ( ^! quantities v>y1 9 consequ5ce ( ! secul> v>iations 9 ! elem5ts ( ! orbits4 ,suppose ! two planets to be on ! same side ( ! sun1 & all ?ree 9 ! same /raight l9e1 !y are !n said to be 9 conjunction 7,n4 #hc74 ,n[1 if !y beg9 to move at ! same "t1 "o mak+ exactly five revolutions 9 its orbit :ile ! o!r only accompli%es two1 x is cle> t ,saturn1 ! sl[-mov+ body1 w only h got ?r\gh a "p ( its orbit dur+ ! "t t ,jupit] has made "o :ole revolution & "p ( ano!r1 be=e !y be aga9 9 conjunction4 ,x is f\nd t dur+ ?is "t _! mutual action is su* z to produce a great _m p]turbations :i* comp5sate ea* o!r1 b t !re /ill rema9s a portion out/&+1 ow+ to ! l5g? ( "t dur+ :i* ! =ces act 9 ! same mann]2 &1 if ! conjunction always happ5$ 9 ! same po9t ( ! orbit1 ?is uncomp5sat$ inequality 9 ! mean motion w\ld g on increas+ till ! p]iodic times & =ms ( ! orbits 7 completely & p]man5tly *ang$3 a case t w\ld actually take place if ,jupit] accompli%$ exactly five revolutions 9 ! "t ,saturn p]=m$ two4 ,^! revolutions are1 h[ev]1 n exactly comm5surable2 ! po9ts 9 :i* ! conjunctions take place are 9 advance ea* "t z mu* z #hcg2 s t ! conjunctions d n happ5 exactly 9 ! same po9ts ( ! orbits till aft] a p]iod ( #hej ye>s2 &1 9 consequ5ce ( ?is small advance1 ! planets are br\ght into su* relative positions1 t ! inequality1 :i* seem$ to ?reat5 ! /ability ( ! sy/em1 is completely comp5sat$1 & ! bodies1 hav+ return$ to ! same relative positions ) reg>d to "o ano!r & ! sun1 beg9 a new c\rse4 ,! secul> v>iations 9 ! elem5ts ( ! orbit increase ! p]iod ( ! inequality to #iah ye>s 7,n4 #hd74 ,z any p]turbation :i* affects ! mean motion affects also ! major axis1 ! di/urb+ =ces t5d to dim9i% ! major axis ( ,jupit]'s orbit1 & increase t ( ,saturn's1 dur+ "o half ( ! p]iod1 & ! contr>y dur+ ! o!r half4 ,?is inequality is /rictly p]iodical1 s9ce x dep5ds ^u ! configuration 7,n4 #he7 ( ! two planets2 & !ory is confirm$ by obs]vation1 :i* %[s t1 9 ! c\rse ( tw5ty c5turies1 ,jupit]'s mean motion has be5 accel]at$ by ab\t #c #bc1 & ,saturn's ret>d$ by #e #ac4 ,sev]al in/ances ( p]turbations ( ?is k9d occur 9 ! sol> sy/em4 ,"o1 9 ! mean motions ( ! ,e>? & ,v5us1 only am\nt+ to a few seconds1 has be5 rec5tly work$ out ) imm5se lab\r by ,pr(essor ,airy4 ,x accompli%es its *anges 9 #bdj ye>s1 & arises f ! circum/ance ( ?irte5 times ! p]iodic "t ( ,v5us be+ ne>ly equal to eight times t ( ! ,e>?4 ,small z x is1 x is s5sible 9 ! motions ( ! ,e>?4 ,x might be imag9$ t ! reciprocal action ( su* planets z h satellites w\ld be diff]5t f ! influ5ce ( ^? t h none4 ,b ! di/ances ( ! satellites f _! prim>ies are incomp>ably less ?an ! di/ances ( ! planets f ! sun1 & f "o ano!r4 ,s t ! sy/em ( a planet & its satellites moves ne>ly z if all ^! bodies 7 unit$ 9 _! common c5tre ( gravity4 ,! action ( ! sun1 h[ev]1 9 "s degree di/urbs ! motion ( ! satellites ab\t _! prim>y4 ,,section ,,iv4 ,!ory ( ,jupit]'s ,satellites--,effects ( ! ,figure ( ,jupit] ^u 8 ,satellites--,position ( _! ,orbits--,s+ul> ,laws among ! ,motions ( ! fir/ ,?ree ,satellites--,eclipses ( ! ,satellites--,velocity ( ,light--,ab]ration--,e!real ,m$ium--,satellites ( ,saturn & ,uranus4 ,,! *anges :i* take place 9 ! planet>y sy/em are exhibit$ on a small] scale by ,jupit] & 8 satellites2 &1 z ! p]iod requisite = ! developm5t ( ! inequalities ( ^! moons only ext5ds to a few c5turies1 x may be reg>d$ z an epitome ( t gr& cycle :i* w n be accompli%$ by ! planets 9 myriads ( ages4 ,! revolutions ( ! satellites ab\t ,jupit] are precisely simil> to ^? ( ! planets ab\t ! sun2 x is true !y are di/urb$ by ! sun1 b 8 di/ance is s great1 t _! motions are ne>ly ! same z if !y 7 n "u 8 influ5ce4 ,! satellites1 l ! planets1 7 probably project$ 9 elliptical orbits3 b1 z ! masses ( ! satellites are ne>ly #ajj1jjj times less ?an t ( ,jupit]2 & z ! compression ( ,jupit]'s sph]oid is s great1 9 consequ5ce ( 8 rapid rotation1 t 8 equatorial diamet] exce$s 8 pol> diamet] by no less ?an #fjjj miles2 ! imm5se quantity ( prom95t matt] at 8 equator mu/ soon h giv5 ! circul> =m obs]v$ 9 ! orbits ( ! fir/ & second satellites1 :i* its sup]ior attraction w always ma9ta94 ,! ?ird & f\r? satellites1 be+ f>!r remov$ f its influ5ce1 revolve 9 orbits ) a v small exc5tricity4 ,&1 al?\gh ! fir/ two s5sibly move 9 circles1 _! orbits acquire a small ellipticity1 f ! di/urbances !y exp]i5ce 7,n4 #hf74 ,x has be5 /at$1 t ! attraction ( a sph]e on an ext]ior body is ! same z if its mass 7 unit$ 9 "o p>ticle 9 its c5tre ( gravity1 & !re=e inv]sely z ! squ>e ( ! di/ance4 ,9 a sph]oid1 h[ev]1 !re is an additional =ce aris+ f ! bulg+ mass at its equator1 :i*1 n foll[+ ! exact law ( gravity1 acts z a di/urb+ =ce4 ,"o effect ( ?is di/urb+ =ce 9 ! sph]oid ( ,jupit] is to occasion a direct motion 9 ! great] axes ( ! orbits ( all 8 satellites1 :i* is m rapid ! ne>] ! satellite is to ! planet1 & v mu* great] ?an t "p ( _! motion :i* arises f ! di/urb+ action ( ! sun4 ,! same cause occasions ! orbits ( ! satellites to rema9 ne>ly 9 ! plane ( ,jupit]'s equator 7,n4 #hg71 on acc\nt ( :i* ! satellites are always se5 ne>ly 9 ! same l9e 7,n4 #hh72 & ! p[]ful action ( t quantity ( prom95t matt] is ! reason :y ! motions ( ! nodes ( ^! small bodies are s mu* m rapid ?an ^? ( ! planet4 ,! nodes ( ! f\r? satellite accompli% a tropical revolution 9 #eca ye>s1 :ile ^? ( ,jupit]'s orbit require no less ?an #cf1bfa ye>s2--a pro( ( ! reciprocal attraction betwe5 ea* p>ticle ( ,jupit]'s equator & ( ! satellites4 ,9 fact1 if ! satellites mov$ exactly 9 ! plane ( ,jupit]'s equator1 !y w\ld n be pull$ out ( t plane1 because 8 attraction w\ld be equal on bo? sides ( x4 ,b1 z _! orbits h a small incl9ation to ! plane ( ! planet's equator1 !re is a want ( symmetry1 & ! action ( ! protub]ant matt] t5ds to make ! nodes regress by pull+ ! satellites above or bel[ ! planes ( _! orbits2 an action :i* is s great on ! int]ior satellites1 t ! motions ( _! nodes are ne>ly ! same z if no o!r di/urb+ =ce exi/$4 ,! orbits ( ! satellites d n reta9 a p]man5t incl9ation1 ei!r to ! plane ( ,jupit]'s equator1 or to t ( 8 orbit1 b to c]ta9 planes pass+ betwe5 ! two1 & ?r\gh _! int]section4 ,^! h a great] incl9ation to 8 equator ! f>!r ! satellite is remov$1 ow+ to ! influ5ce ( ,jupit]'s compression2 & !y h a sl[ motion correspond+ to secul> v>iations 9 ! planes ( ,jupit]'s orbit & equator4 ,! satellites are n only subject to p]iodic & secul> inequalities f _! mutual attraction1 simil> to ^? :i* affect ! motions & orbits ( ! planets1 b also to o!rs peculi> to !mselves4 ,( ! p]iodic inequalities aris+ f _! mutual attraction ! mo/ rem>kable take place 9 ! angul> motions 7,n4 #hi7 ( ! ?ree ne>e/ to ,jupit]1 ! second ( :i* receives f ! fir/ a p]turbation simil> to t :i* x produces 9 ! ?ird2 & x exp]i5ces f ! ?ird a p]turbation simil> to t :i* x communicates to ! fir/4 ,9 ! eclipses ^! two inequalities are comb9$ into "o1 ^: p]iod is #dcgfei days4 ,! v>iations peculi> to ! satellites arise f ! secul> inequalities occasion$ by ! action ( ! planets 9 ! =m & position ( ,jupit]'s orbit1 & f ! displacem5t ( 8 equator4 ,x is obvi\s t :atev] alt]s ! relative positions ( ! sun1 ,jupit]1 & 8 satellites1 mu/ occasion a *ange 9 ! directions & int5sities ( ! =ces1 :i* w affect ! motions & orbits ( ! satellites4 ,= ?is reason ! secul> v>iations 9 ! exc5tricity ( ,jupit]'s orbit occasion secul> inequalities 9 ! mean motions ( ! satellites1 & 9 ! motions ( ! nodes & apsides ( _! orbits4 ,! displacem5t ( ! orbit ( ,jupit]1 & ! v>iation 9 ! position ( 8 equator1 also affect ^! small bodies 7,n4 #ij74 ,! plane ( ,jupit]'s equator is incl9$ to ! plane ( 8 orbit at an angle ( #c #e #cj1 s t ! action ( ! sun & ( ! satellites !mselves produces a nutation & precession 7,n4 #ia7 9 8 equator1 precisely simil> to t :i* takes place 9 ! rotation ( ! e>?1 f ! action ( ! sun & moon4 ,h5ce ! protub]ant matt] at ,jupit]'s equator is cont9ually *ang+ its position ) reg>d to ! satellites1 & produces correspond+ mutations 9 _! motions4 ,&1 z ! cause mu/ be proportional to ! effect1 ^! inequalities af=d ! means1 n only ( asc]ta9+ ! compression ( ,jupit]'s sph]oid1 b !y prove t 8 mass is n homog5e\s4 ,al?\gh ! app>5t diamet]s ( ! satellites are too small to be measur$1 yet _! p]turbations give ! values ( _! masses ) consid]able accuracy--a /rik+ pro( ( ! p[] ( analysis4 ,a s+ul> law obta9s among ! mean motions & mean longitudes ( ! fir/ ?ree satellites4 ,x appe>s f obs]vation t ! mean motion ( ! fir/ satellite1 plus twice t ( ! ?ird1 is equal to ?ree times t ( ! second2 & t ! mean longitude ( ! fir/ satellite1 m9us ?ree times t ( ! second1 plus twice t ( ! ?ird1 is always equal to two "r angles4 ,x is prov$ by !ory1 t1 if ^! relations _h only be5 approximate :5 ! satellites 7 fir/ laun*$ into space1 _! mutual attractions w\ld h e/abli%$ & ma9ta9$ !m1 not)/&+ ! secul> inequalities to :i* !y are liable4 ,!y ext5d to ! synodic motions 7,n4 #ib7 ( ! satellites2 consequ5tly !y affect _! eclipses1 & h a v great influ5ce on _! :ole !ory4 ,! satellites move s ne>ly 9 ! plane ( ,jupit]'s equator1 :i* has a v small incl9ation to 8 orbit1 t ! fir/ ?ree are eclips$ at ea* revolution by ! %ad[ ( ! planet1 :i* is mu* l>g] ?an ! %ad[ ( ! moon3 ! f\r? satellite is n eclips$ s frequ5tly z ! o!rs4 ,! eclipses take place close to ! disc ( ,jupit] :5 he is ne> opposition 7,n4 #ic72 b at times 8 %ad[ is s project$ ) reg>d to ! e>?1 t ! ?ird & f\r? satellites vani% & reappe> on ! same side ( ! disc 7,n4 #id74 ,^! eclipses are 9 all respects simil> to ^? ( ! moon3 b1 occasionally1 ! satellites eclipse ,jupit]1 sometimes pass+ l obscure spots across 8 surface1 resembl+ annul> eclipses ( ! sun1 & sometimes l a bright spot trav]s+ "o ( 8 d>k belts4 ,be=e opposition1 ! %ad[ ( ! satellite1 l a r\nd black spot1 prec$es its passage ov] ! disc ( ! planet2 &1 aft] opposition1 ! %ad[ foll[s ! satellite4 ,9 consequ5ce ( ! relations already m5tion$ 9 ! mean motions & mean longitudes ( ! fir/ ?ree satellites1 !y nev] c be all eclips$ at ! same "t3 =1 :5 ! second & ?ird are 9 "o direction1 ! fir/ is 9 ! opposite direction2 consequ5tly1 :5 ! fir/ is eclips$1 ! o!r two mu/ be betwe5 ! sun & ,jupit]4 ,! in/ant ( ! beg9n+ or end ( an eclipse ( a satellite m>ks ! same in/ant ( absolute "t to all ! inhabitants ( ! e>?2 !re=e1 ! "t ( ^! eclipses obs]v$ by a travell]1 :5 comp>$ ) ! "t ( ! eclipse comput$ = ,gre5wi*1 or any o!r fix$ m]idian 7,n4 #ie71 gives ! diff]5ce ( ! m]idians 9 "t1 &1 consequ5tly1 ! longitude ( ! place ( obs]vation4 ,! longitude is det]m9$ ) extreme precision :5ev] x is possible to convey ! "t in/antane\sly by means ( electricity f "o place to ano!r1 s9ce x obviates ! errors ( clocks & *ronomet]s4 ,! eclipses ( ,jupit]'s satellites h be5 ! means ( a discov]y :i*1 ?\gh n s imm$iately applicable to ! wants ( man1 unfolds "o ( ! prop]ties ( light--t m$ium )\t ^: *e]+ influ5ce all ! beauties ( ! creation w\ld h be5 to u a blank4 ,x is obs]v$1 t ^? eclipses ( ! fir/ satellite :i* happ5 :5 ,jupit] is ne> conjunction 7,n4 #if71 are lat] by #af #bff ?an ^? :i* take place :5 ! planet is 9 opposition4 ,z ,jupit] is ne>] to u :5 9 opposition by ! :ole bread? ( ! e>?'s orbit ?an :5 9 conjunction1 ?is circum/ance is to be attribut$ to ! "t employ$ by ! rays ( light 9 cross+ ! e>?'s orbit1 a di/ance ( ab\t #aij1jjj1jjj ( miles2 :5ce x is e/imat$ t light travels at ! rate ( #aib1jjj miles 9 "o second4 ,su* is its velocity1 t ! e>?1 mov+ at ! rate ( n9ete5 miles 9 a second1 w\ld take two mon?s to pass ?r\gh a di/ance :i* a ray ( light w\ld d>t ov] 9 eight m9utes4 ,! subsequ5t discov]y ( ! ab]ration ( light has fully confirm$ ?is a/oni%+ result4 ,objects appe> to be situate 9 ! direction ( ! rays :i* proce$ f !m4 ,7 light propagat$ in/antane\sly1 e object1 :e!r at re/ or 9 motion1 w\ld appe> 9 ! direction ( ^! rays2 b1 z light takes "s "t to travel1 we see ,jupit] 9 conjunction1 by means ( rays t left him #afm #bfs#f be=e2 b1 dur+ t "t1 we h *ang$ our position1 9 consequ5ce ( ! motion ( ! e>? 9 its orbit3 we !re=e ref] ,jupit] to a place 9 :i* he is n4 ,8 true position is 9 ! diagonal 7,n4 #ig7 ( ! p>allelogram1 ^: sides are 9 ! ratio ( ! velocity ( light to ! velocity ( ! e>? 9 its orbit1 :i* is z #aib1jjj to #ai1 or ne>ly z #aj1jjj to #a4 ,9 consequ5ce ( ! ab]ration ( light1 ! heav5ly bodies seem to be 9 places 9 :i* !y are n4 ,9 fact1 if ! e>? 7 at re/1 rays f a /> w\ld pass along ! axis ( a telescope direct$ to x2 b1 if ! e>? 7 to beg9 to move 9 its orbit ) its usual velocity1 ^! rays w\ld /rike aga9/ ! side ( ! tube2 x w\ld1 !re=e1 be necess>y to incl9e ! telescope a little1 9 ord] to see ! />4 ,! angle conta9$ betwe5 ! axis ( ! telescope & a l9e drawn to ! true place ( ! /> is its ab]ration1 :i* v>ies 9 quantity & direction 9 diff]5t p>ts ( ! e>?'s orbit2 b1 z x is only #bjdha1 x is ins5sible 9 ord9>y cases 7,n4 #ih74 ,! velocity ( light d$uc$ f ! obs]v$ ab]ration ( ! fix$ />s p]fectly corresponds ) t giv5 by ! eclipses ( ! fir/ satellite4 ,! same result1 obta9$ f s\rces s diff]5t1 leaves n a d\bt ( its tru?4 ,_m su* beautiful co9cid5ces1 d]iv$ f circum/ances app>5tly ! mo/ unpromis+ & dissimil>1 occur 9 physical a/ronomy1 & prove connections :i* we might o!rwise be unable to trace4 ,! id5tity ( ! velocity ( light1 at ! di/ance ( ,jupit]1 & on ! e>?'s surface1 %[s t its velocity is uni=m2 & z light consi/s 9 ! vibrations ( an ela/ic m$ium or e!r fill+ space1 ! uni=mity ( its velocity %[s t ! d5sity ( ! m$ium ?r\gh\t ! :ole ext5t ( ! sol> sy/em mu/ be proportional to its ela/icity 7,n4 #ii74 ,among ! =tunate conjectures :i* h be5 confirm$ by subsequ5t exp]i5ce1 t ( ,bacon is n ! lea/ rem>kable1 8,x produces 9 me10 says ! re/or] ( true philosophy1 8a d\bt :e!r ! face ( ! s]5e & />ry heav5s be se5 at ! in/ant x really exi/s1 or n till "s "t lat]3 & :e!r !re be n1 ) respect to ! heav5ly bodies1 a true "t & an app>5t "t1 no less ?an a true place & an app>5t place1 z a/ronom]s say1 on acc\nt ( p>allax4 ,= x seems incr$ible t ! species or rays ( ! cele/ial bodies c pass ?r\gh ! imm5se int]val betwe5 !m & u 9 an in/ant1 or t !y d n ev5 require "s consid]able portion ( "t40 ,great discov]ies g5]ally lead to a v>iety ( conclusions3 ! ab]ration ( light af=ds a direct pro( ( ! motion ( ! e>? 9 its orbit2 & its rotation is prov$ by ! !ory ( fall+ bodies1 s9ce ! c5trifugal =ce x induces ret>ds ! oscillations ( ! p5dulum 7,n4 #ajj7 9 go+ f ! pole to ! equator4 ,?us a high degree ( sci5tific k has be5 requisite to dispel ! errors ( ! s5ses 7,n4 #bcg74 ,! little t is kn[n ( ! !ories ( ! satellites ( ,saturn & ,uranus is1 9 all respects1 simil> to t ( ,jupit]4 ,saturn is accompani$ by eight satellites4 ,! sev5? is ab\t ! size ( ,m>s1 & ! eigh? 0 simultane\sly discov]$ by ,mr4 ,bond 9 ,am]ica1 & t di/+ui%$ a/ronom] ,mr4 ,lassell1 ( ,liv]pool4 ,! orbits ( ! two la/ h a s5sible incl9ation to ! plane ( ! r+2 b ! great compression ( ,saturn occasions ! o!r satellites to move ne>ly 9 ! plane ( 8 equator4 ,s _m circum/ances mu/ concur to r5d] ! two int]ior satellites visible1 t !y h v r>ely be5 se54 ,!y move exactly at ! edge ( ! r+1 & _! orbits nev] deviate f its plane4 ,9 #aghi ,sir ,william ,h]s*el saw !m l beads1 ?read+ ! sl5d] l9e ( light :i* ! r+ is r$uc$ to :5 se5 edgewise f ! e>?4 ,& = a %ort "t he p]ceiv$ !m advanc+ (f x at ea* end1 :5 turn+ r\nd 9 _! orbits4 ,! eclipses ( ! ext]ior satellites only take place :5 ! r+ is 9 ?is position4 ,mr4 ,lassell1 ) a p[]ful telescope1 made by himself1 has se5 ,iapetus1 ! ne>e/ ( ! two1 on sev]al occasions1 ev5 :5 ! op5+ ( ! r+ 0 v wide1 :i* made x extremely difficult to see s m9ute an object4 ,( ! situation ( ! equator ( ,uranus we "k no?+1 nor ( 8 compression2 b ! orbits ( 8 satellites are ne>ly p]p5dicul> to ! plane ( ! ecliptic2 &1 by analogy1 !y ought to be 9 ! plane ( 8 equator4 ,uranus is s remote t he has m ! appe>ance ( a planet>y nebula ?an a planet1 :i* r5d]s x extremely difficult to di/+ui% ! satellites at all2 & q hopeless )\t su* a telescope z is r>ely to be met ) ev5 9 obs]vatories4 ,sir ,william ,h]s*el discov]$ ! two t are f>!/ f ! planet1 & asc]ta9$ _! approximate p]iods1 :i* 8 son aft]w>ds det]m9$ to be #ac;d #aa;h #gm #abs#f & #h;d #af;h #efm #bhs#f respectively4 ,! orbits ( bo? seem to h an incl9ation ( ab\t #ajab to ! plane ( ! ecliptic4 ,! two int]ior satellites are s fa9t & small1 & s ne> ! edge ( ! planet1 t !y c ) difficulty be se5 ev5 "u ! mo/ fav\rable circum/ances3 h[ev]1 ,mr4 ,lassell has asc]ta9$ t ! m di/ant ( ! two revolves ab\t ,uranus 9 #d days1 & t ne>e/ to ! planet 9 #b-a_/b days1 & f a long & m9ute exam9ation he is conv9c$ t ! sy/em only consi/s ( f\r satellites4 ,soon aft] ,neptune 0 se5 ,mr4 ,lassell discov]$ ! only satellite kn[n to belong to t planet4 ,! satellites ( ,uranus & ,neptune1 ! two planets on ! remote/ v]ge ( ! sol> sy/em1 (f] ! s+ul> & only in/ance ( a revolution f ea/ to we/1 :ile all ! planets & all ! o!r satellites revolve f we/ to ea/4 ,retrograde motion is occasionally met ) 9 ! comets & d\ble />s4 ,,section ,v4 ,lun> ,!ory--,p]iodic ,p]turbations ( ! ,moon--,equation ( ,c5tre--,evection--,v>iation--,annual ,equation--,direct & ,indirect ,action ( ,planets--,! ,moon's ,action on ! ,e>? di/urbs h] own ,motion--,exc5tricity & ,incl9ation ( ,lun> ,orbit inv>iable--,accel]ation--,secul> ,v>iation 9 ,nodes & ,p]igee--,motion ( ,nodes & ,p]igee insep>ably connect$ ) ! ,accel]ation--,nutation ( ,lun> ,orbit--,=m & ,int]nal ,/ructure ( ! ,e>? det]m9$ f x--,lun>1 ,sol>1 & ,planet>y ,eclipses--,occultations & ,lun> ,di/ances--,mean ,di/ance ( ! ,sun f ! ,e>? obta9$ f ,lun> ,!ory--,absolute ,di/ances ( ! ,planets1 h[ f\nd4 ,,our con/ant companion1 ! moon1 next claims our att5tion4 ,sev]al circum/ances concur to r5d] h] motions ! mo/ int]e/+1 & at ! same "t ! mo/ difficult to inve/igate1 ( all ! bodies ( our sy/em4 ,9 ! sol> sy/em1 planet tr\bles planet2 b1 9 ! lun> !ory1 ! sun is ! great di/urb+ cause1 8 va/ di/ance be+ comp5sat$ by 8 enorm\s magnitude1 s t ! motions ( ! moon are m irregul> ?an ^? ( ! planets2 &1 on acc\nt ( ! great ellipticity ( h] orbit1 & ! size ( ! sun1 ! approximations to h] motions are t$i\s & difficult1 beyond :at ^? unaccu/om$ to su* inve/igations c\ld imag9e4 ,! av]age di/ance ( ! moon f ! c5tre ( ! e>? is only #bch1gic miles1 s t h] motion among ! />s is p]ceptible 9 a few h\rs4 ,%e completes a circuit ( ! heav5s 9 #bg;d #g;h #dcm #aas#e1 mov+ 9 an orbit ^: exc5tricity is ab\t #ab1ihe miles4 ,! moon is ab\t f\r hundr$ times ne>] to ! e>? ?an ! sun4 ,! proximity ( ! moon to ! e>? keeps !m toge!r4 ,= s great is ! attraction ( ! sun1 t1 if ! moon 7 f>!r f ! e>?1 %e w\ld leave x altoge!r1 & w\ld revolve z an indep5d5t planet ab\t ! sun4 ,! di/urb+ action 7,n4 #aja7 ( ! sun on ! moon is equival5t to ?ree =ces4 ,! fir/1 act+ 9 ! direction ( ! l9e jo9+ ! moon & e>?1 increases or dim9i%es h] gravity to ! e>?4 ,! second1 act+ 9 ! direction ( a tang5t to h] orbit1 di/urbs h] motion 9 longitude4 ,& ! ?ird1 act+ p]p5dicul>ly to ! plane ( h] orbit1 di/urbs h] motion 9 latitude2 t is1 x br+s h] ne>] to1 or removes h] f>!r f1 ! plane ( ! ecliptic ?an %e w\ld o!rwise be4 ,! p]iodic p]turbations 9 ! moon1 aris+ f ^! =ces1 are p]fectly simil> to ! p]iodic p]turbations ( ! planets4 ,b !y are mu* great] & m num]\s2 because ! sun is s l>ge1 t _m inequalities :i* are q ins5sible 9 ! motions ( ! planets1 are ( great magnitude 9 ^? ( ! moon4 ,among ! innum]able p]iodic inequalities to :i* ! moon's motion 9 longitude is liable1 ! mo/ rem>kable are1 ! ,equation ( ! ,c5tre1 :i* is ! diff]5ce betwe5 ! moon's mean & true longitude1 ! ,evection1 ! ,v>iation1 & ! ,annual ,equation4 ,! di/urb+ =ce :i* acts 9 ! l9e jo9+ ! moon & e>? produces ! ,evection3 x dim9i%es ! exc5tricity ( ! lun> orbit 9 conjunction & opposition1 !reby mak+ x m circul>1 & augm5ts x 9 quadrature1 :i* consequ5tly r5d]s x m elliptical4 ,! p]iod ( ?is inequality is less ?an ?irty-two days4 ,7 ! increase & dim9ution always ! same1 ! ,evection w\ld only dep5d ^u ! di/ance ( ! moon f ! sun2 b its absolute value also v>ies ) h] di/ance f ! p]igee 7,n4 #ajb7 ( h] orbit4 ,anci5t a/ronom]s1 :o obs]v$ ! moon solely ) a view to ! pr$iction ( eclipses1 :i* c only happ5 9 conjunction & opposition1 :]e ! exc5tricity is dim9i%$ by ! ,evection1 assign$ too small a value to ! ellipticity ( h] orbit 7,n4 #ajc74 ,! ,evection 0 discov]$ by ,ptolemy f obs]vation1 ab\t ,a4,d4 #adj4 ,! ,v>iation produc$ by ! tang5tial di/urb+ =ce1 :i* is at its maximum :5 ! moon is #de di/ant f ! sun1 vani%es :5 t di/ance am\nts to a quadrant1 & also :5 ! moon is 9 conjunction & opposition2 consequ5tly1 t inequality nev] c\ld h be5 discov]$ f ! eclipses3 its p]iod is half a lun> mon? 7,n4 #ajd74 ,! ,annual ,equation dep5ds ^u ! sun's di/ance f ! e>?3 x arises f ! moon's motion be+ accel]at$ :5 t ( ! e>? is ret>d$1 & vice v]s--=1 :5 ! e>? is 9 its p]ihelion1 ! lun> orbit is enl>g$ by ! action ( ! sun2 !re=e1 ! moon requires m "t to p]=m h] revolution4 ,b1 z ! e>? approa*es its aphelion1 ! moon's orbit contracts1 & less "t is necess>y to accompli% h] motion--its p]iod1 consequ5tly1 dep5ds ^u ! "t ( ! ye>4 ,9 ! eclipses ! ,annual ,equation comb9es ) ! ,equation ( ! ,c5tre ( ! t]re/rial orbit1 s t anci5t a/ronom]s imag9$ ! e>?'s orbit to h a great] exc5tricity ?an mod]n a/ronom]s assign to x4 ,! planets di/urb ! motion ( ! moon bo? directly & indirectly2 _! action on ! e>? alt]s its relative position ) reg>d to ! sun & moon1 & occasions inequalities 9 ! moon's motion1 :i* are m consid]able ?an ^? aris+ f _! direct action2 = ! same reason ! moon1 by di/urb+ ! e>?1 indirectly di/urbs h] own motion4 ,nei!r ! exc5tricity ( ! lun> orbit1 nor its mean incl9ation to ! plane ( ! ecliptic1 h exp]i5c$ any *anges f secul> inequalities2 =1 al?\gh ! mean action ( ! sun on ! moon dep5ds ^u ! incl9ation ( ! lun> orbit to ! ecliptic1 & ! position ( ! ecliptic is subject to a secul> inequality1 yet analysis %[s t x does n occasion a secul> v>iation 9 ! incl9ation ( ! lun> orbit1 because ! action ( ! sun con/antly br+s ! moon's orbit to ! same incl9ation to ! ecliptic4 ,! mean motion1 ! nodes1 & ! p]igee1 h[ev]1 are subject to v rem>kable v>iations4 ,f ! eclipse obs]v$ at ,babylon1 on ! #ai? ( ,m>*1 sev5 hundr$ & tw5ty-"o ye>s be=e ! ,*ri/ian era1 ! place ( ! moon is kn[n f t ( ! sun at ! in/ant ( opposition 7,n4 #hc71 :5ce h] mean longitude may be f\nd4 ,b ! comp>ison ( ?is mean longitude ) ano!r mean longitude1 comput$ back = ! in/ant ( ! eclipse f mod]n obs]vations1 %[s t ! moon p]=ms h] revolution r\nd ! e>? m rapidly & 9 a %ort] "t n[ ?an %e did =m]ly1 & t ! accel]ation 9 h] mean motion has be5 increas+ f age to age z ! squ>e ( ! "t 7,n4 #aje74 ,all anci5t & int]m$iate eclipses confirm ?is result4 ,z ! mean motions ( ! planets h no secul> inequalities1 ?is seem$ to be an unacc\ntable anomaly4 ,x 0 at "o "t attribut$ to ! resi/ance ( an e!real m$ium p]vad+ space1 & at ano!r to ! successive transmission ( ! gravitat+ =ce4 ,b1 z ,la ,place prov$ t nei!r ( ^! causes1 ev5 if !y exi/1 h any influ5ce on ! motions ( ! lun> p]igee 7,n4 #ajb7 or nodes1 !y c\ld n affect ! mean motion2 a v>iation 9 ! mean motion f su* causes be+ insep>ably connect$ ) v>iations 9 ! motions ( ! p]igee & nodes4 ,t great ma!matician1 9 /udy+ ! !ory ( ,jupit]'s satellites1 p]ceiv$ t ! secul> v>iation 9 ! elem5ts ( ,jupit]'s orbit1 f ! action ( ! planets1 occasions correspond+ *anges 9 ! motions ( ! satellites1 :i* l$ him to suspect t ! accel]ation 9 ! mean motion ( ! moon might be connect$ ) ! secul> v>iation 9 ! exc5tricity ( ! t]re/rial orbit4 ,analysis has %[n t he assign$ ! true cause ( ! accel]ation4 ,x is prov$ t ! great] ! exc5tricity ( ! t]re/rial orbit1 ! great] is ! di/urb+ action ( ! sun on ! moon4 ,n[1 z ! exc5tricity has be5 decreas+ = ages1 ! effect ( ! sun 9 di/urb+ ! moon has be5 dim9i%+ dur+ t "t4 ,consequ5tly ! attraction ( ! e>? has _h a m & m p[]ful effect on ! moon1 & has be5 cont9ually dim9i%+ ! size ( ! lun> orbit4 ,s t ! moon's velocity has be5 gradually augm5t+ = _m c5turies to balance ! increase ( ! e>?'s attraction4 ,?is secul> increase 9 ! moon's velocity is call$ ! ,accel]ation1 a "n peculi>ly appropriate at pres5t1 & :i* w cont9ue to be s = a va/ numb] ( ages2 because1 z long z ! e>?'s exc5tricity dim9i%es1 ! moon's mean motion w be accel]at$2 b :5 ! exc5tricity has pass$ its m9imum1 & beg9s to increase1 ! mean motion w be ret>d$ f age to age4 ,! secul> accel]ation is n[ ab\t #aai1 b its effect on ! moon's place increases z ! squ>e ( ! "t 7,n4 #ajf74 ,x is rem>kable t ! action ( ! planets1 ?us reflect$ by ! sun to ! moon1 is mu* m s5sible ?an _! direct action ei!r on ! e>? or moon4 ,! secul> dim9ution 9 ! exc5tricity1 :i* has n alt]$ ! equation ( ! c5tre ( ! sun by eight m9utes s9ce ! e>lie/ record$ eclipses1 has produc$ a v>iation ( ab\t #a #dh 9 ! moon's longitude1 & ( #g #ab 9 h] mean anomaly 7,n4 #ajg74 ,! action ( ! sun occasions a rapid b v>iable motion 9 ! nodes & p]igee ( ! lun> orbit4 ,?\gh ! nodes rec$e dur+ ! great] "p ( ! moon's revolution1 & advance dur+ ! small]1 !y p]=m _! sid]eal revolution 9 #fgic;d #i;h #bcm #is#c1 or ab\t #ah-f_/aj ye>s2 & ! p]igee accompli%es a revolution1 call$ ( ! moon's apsides1 9 #cbcb;d #ac;h #dhm #bis#f1 or a little m ?an n9e ye>s1 not)/&+ its motion is sometimes retrograde & sometimes direct3 b su* is ! diff]5ce betwe5 ! di/urb+ en]gy ( ! sun & t ( all ! planets put toge!r1 t x requires no less ?an #aji1hcj ye>s = ! great] axis ( ! t]re/rial orbit to d ! same1 mov+ at ! rate ( #aah annually4 ,! =m ( ! e>? has no s5sible effect ei!r on ! lun> nodes or apsides4 ,x is evid5t t ! same secul> v>iation :i* *anges ! sun's di/ance f ! e>?1 & occasions ! accel]ation 9 ! moon's mean motion1 mu/ affect ! nodes & p]igee4 ,x consequ5tly appe>s1 f !ory z well z obs]vation1 t bo? ^! elem5ts are subject to a secul> inequality1 aris+ f ! v>iation 9 ! exc5tricity ( ! e>?'s orbit1 :i* connects !m ) ! ,accel]ation1 s t bo? are ret>d$ :5 ! mean motion is anticipat$4 ,! secul> v>iations 9 ^! ?ree elem5ts are 9 ! ratio ( ! numb]s #c1 #jgce1 & #a2 :5ce ! ?ree motions ( ! moon1 ) reg>d to ! sun1 to h] p]igee1 & to h] nodes1 are cont9ually accel]at$1 & _! secul> equations are z ! numb]s #a1 #dgjb1 & #jfab4 ,a comp>ison ( anci5t eclipses obs]v$ by ! ,arabs1 ,greeks1 & ,*aldeans1 imp]fect z !y are1 ) mod]n obs]vations1 confirms ^! results ( analysis4 ,future ages w develop ^! great inequalities1 :i* at "s mo/ di/ant p]iod w am\nt to _m circumf]5ces 7,n4 #ajh74 ,!y are1 inde$1 p]iodic2 b :o %all tell _! p]iod8 ,millions ( ye>s mu/ elapse be=e t great cycle is accompli%$4 ,! moon is s ne>1 t ! excess ( matt] at ! e>?'s equator occasions p]iodic v>iations 9 h] longitude1 & also t rem>kable inequality 9 h] latitude1 already m5tion$ z a nutation 9 ! lun> orbit1 :i* dim9i%es its incl9ation to ! ecliptic :5 ! moon's asc5d+ node co9cides ) ! equ9ox ( spr+1 & augm5ts x :5 t node co9cides ) ! equ9ox ( autumn4 ,z ! cause mu/ be proportional to ! effect1 a comp>ison ( ^! inequalities1 comput$ f !ory1 ) ! same giv5 by obs]vation1 %[s t ! compression ( ! t]re/rial sph]oid1 or ! ratio ( ! diff]5ce betwe5 ! pol> & ! equatorial diamet]s1 to ! diamet] ( ! equator1 is #a_/cjeje4 ,x is prov$ analytically1 t1 if a fluid mass ( homog5e\s matt]1 ^: p>ticles attract ea* o!r inv]sely z ! squ>es ( ! di/ance1 7 to revolve ab\t an axis z ! e>? does1 x w\ld assume ! =m ( a sph]oid ^: compression is #a_/bcj4 ,s9ce t is n ! case1 ! e>? _c be homog5e\s1 b mu/ decrease 9 d5sity f its c5tre to its circumf]5ce4 ,?us ! moon's eclipses %[ ! e>? to be r\nd2 & h] inequalities n only det]m9e ! =m1 b ev5 ! int]nal /ructure ( our planet2 results ( analysis :i* c\ld n h be5 anticipat$4 ,simil> inequalities 9 ! motions ( ,jupit]'s satellites prove t 8 mass is n homog5e\s1 & t 8 compression is #a_/ach4 ,8 equatorial diamet] exce$s 8 pol> diamet] by ab\t #fjjj miles4 ,! phases 7,n4 #aji7 ( ! moon1 :i* v>y f a sl5d] silv]y cresc5t soon aft] conjunction1 to a complete circul> disc ( light 9 opposition1 decrease by ! same degrees till ! moon is aga9 envelop$ 9 ! morn+ beams ( ! sun4 ,^! *anges regulate ! returns ( ! eclipses4 ,^? ( ! sun c only happ5 9 conjunction1 :5 ! moon1 com+ betwe5 ! e>? & ! sun1 int]cepts 8 light4 ,^? ( ! moon are occasion$ by ! e>? int]v5+ betwe5 ! sun & moon :5 9 opposition4 ,z ! e>? is opaque & ne>ly sph]ical1 x ?r[s a conical %ad[ on ! side ( ! moon opposite to ! sun1 ! axis ( :i* passes ?r\gh ! c5tres ( ! sun & e>? 7,n4 #aaj74 ,! l5g? ( ! %ad[ t]m9ates at ! po9t :]e ! app>5t diamet]s 7,n4 #aaa7 ( ! sun & e>? w\ld be ! same4 ,:5 ! moon is 9 opposition1 & at h] mean di/ance1 ! diamet] ( ! sun w\ld be se5 f h] c5tre "u an angle ( #aiaha4 ,t ( ! e>? w\ld appe> "u an angle ( #fijhc4 ,s t ! l5g? ( ! %ad[ is at lea/ ?ree times & a half great] ?an ! di/ance ( ! moon f ! e>?1 & ! bread? ( ! %ad[1 :]e x is trav]s$ by ! moon1 is ab\t eight-?irds ( ! lun> diamet]4 ,h5ce ! moon w\ld be eclips$ e "t %e is 9 opposition1 7 x n = ! incl9ation ( h] orbit to ! plane ( ! ecliptic1 9 consequ5ce ( :i* ! moon1 :5 9 opposition1 is ei!r above or bel[ ! cone ( ! e>?'s %ad[1 except :5 9 or ne> h] nodes4 ,h] position ) reg>d to !m occasions all ! v>ieties 9 ! lun> eclipses4 ,e po9t ( ! moon's surface successively loses ! light ( diff]5t p>ts ( ! sun's disc be=e be+ eclips$4 ,h] brightness !re=e gradually dim9i%es be=e %e plunges into ! e>?'s %ad[4 ,! bread? ( ! space occupi$ by ! p5umbra 7,n4 #aab7 is equal to ! app>5t diamet] ( ! sun1 z se5 f ! c5tre ( ! moon4 ,! mean duration ( a revolution ( ! sun1 ) reg>d to ! node ( ! lun> orbit1 is to ! duration ( a synodic revolution 7,n4 #aac7 ( ! moon z #bbc to #ai4 ,s t1 aft] a p]iod ( #bbc lun> mon?s1 ! sun & moon w\ld return to ! same relative position ) reg>d to ! node ( ! moon's orbit1 & !re=e ! eclipses w\ld recur 9 ! same ord] 7 n ! p]iods alt]$ by irregul>ities 9 ! motions ( ! sun & moon4 ,9 lun> eclipses1 our atmosph]e b5ds ! sun's rays :i* pass ?r\gh x all r\nd into ! cone ( ! e>?'s %ad[4 ,& z ! horizontal refraction 7,n4 #aad7 or b5d+ ( ! rays surpasses half ! sum ( ! semidiamet]s ( ! sun & moon1 divid$ by _! mutual di/ance1 ! c5tre ( ! lun> disc1 suppos$ to be 9 ! axis ( ! %ad[1 w\ld receive ! rays f ! same po9t ( ! sun1 r\nd all sides ( ! e>?2 s t x w\ld be m illum9at$ ?an 9 full moon1 if ! great] portion ( ! light 7 n /opp$ or absorb$ by ! atmosph]e4 ,in/ances are record$ :]e ?is feeble light has be5 entirely absorb$1 s t ! moon has altoge!r disappe>$ 9 h] eclipses4 ,! sun is eclips$ :5 ! moon int]cepts 8 rays 7,n4 #aae74 ,! moon1 ?\gh incomp>ably small] ?an ! sun1 is s mu* ne>] ! e>?1 t h] app>5t diamet] diff]s b little f 81 b bo? are liable to su* v>iations t !y alt]nately surpass "o ano!r4 ,7 ! eye ( a spectator 9 ! same /raight l9e ) ! c5tres ( ! sun & moon1 he w\ld see ! sun eclips$4 ,if ! app>5t diamet] ( ! moon surpass$ t ( ! sun1 ! eclipse w\ld be total4 ,if x 7 less1 ! obs]v] w\ld see a r+ ( light r\nd ! disc ( ! moon1 & ! eclipse w\ld be annul>1 z x 0 on ! #ag? ( ,may1 #ahcf1 & on ! #ae? ( ,m>*1 #aheh4 ,if ! c5tre ( ! moon %\ld n be 9 ! /raight l9e jo9+ ! c5tres ( ! sun & ! eye ( ! obs]v]1 ! moon might only eclipse a "p ( ! sun4 ,! v>iation1 !re=e1 9 ! di/ances ( ! sun & moon f ! c5tre ( ! e>?1 & ( ! moon f h] node at ! in/ant ( conjunction1 occasions great v>ieties 9 ! sol> eclipses4 ,besides1 ! height ( ! moon above ! horizon *anges h] app>5t diamet]1 & may augm5t or dim9i% ! app>5t di/ances ( ! c5tres ( ! sun & moon1 s t an eclipse ( ! sun may occur to ! inhabitants ( "o c\ntry1 & n to ^? ( ano!r4 ,9 ?is respect ! sol> eclipses diff] f ! lun>1 :i* are ! same = e "p ( ! e>? :]e ! moon is above ! horizon4 ,9 sol> eclipses1 ! light reflect$ by ! atmosph]e dim9i%es ! obscurity !y produce4 ,ev5 9 total eclipses ! high] "p ( ! atmosph]e is enlight5$ by a "p ( ! sun's disc1 & reflects its rays to ! e>?4 ,! :ole disc ( ! new moon is frequ5tly visible f atmosph]ic reflection4 ,dur+ ! eclipse ( ! #ai? ( ,m>*1 #ahdi1 ! spots on ! lun> disc 7 di/9ctly visible1 & dur+ t ( #ahef ! moon 0 l a beautiful rose-col\r$ ball float+ 9 ! e!r3 ! col\r is ow+ to ! refraction ( ! sun's light pass+ ?r\gh ! e>?'s atmosph]e4 ,9 total sol> eclipses ! sl5d] lum9\s arc t is visible = a few seconds be=e ! sun vani%es & also be=e he reappe>s1 resembles a /r+ ( pe>ls surr\nd+ ! d>k edge ( ! moon2 x is occasion$ by ! sun's rays pass+ betwe5 ! tops ( ! lun> m\nta9s3 x occurs likewise 9 annul> eclipses4 ,a ph5om5on altoge!r unprec$5t$ 0 se5 dur+ ! total eclipse ( ! sun :i* happ5$ on ! #h? ( ,july1 #ahdb4 ,! moon 0 l a black pat* on ! sky surr\nd$ by a fa9t :iti% light or corona ab\t ! eigh? ( ! moon's diamet] 9 bread?1 :i* is suppos$ to be ! sol> atmosph]e r5d]$ visible by ! int]v5tion ( ! moon4 ,9 ?is :iti% corona !re appe>$ ?ree rose-col\r$ flames l ! tee? ( a saw4 ,simil> flames 7 also se5 9 ! :ite corona ( ! total eclipse :i* took place 9 #ahea1 & a long rose-col\r$ *a9 ( :at appe>$ to be jagg$ m\nta9s or si]ras unit$ at ! base by a r$ b& seem$ to be rais$ into ! corona by mirage2 b !re is no d\bt t ! corona & r$ ph5om5a belong to ! sun4 ,?is r$ *a9 0 s bright t ,mr4 ,airy saw x illum9ate ! nor!rn horizon ?r\gh an azimu? ( #ij ) r$ light4 ,m4 ,faye attributes ! rose-col\r$ protub]ances to ! con/itution ( ! sun1 :i*1 l ,sir ,william ,h]s*el1 he conceives to be an inc&esc5t globe1 consi/+ ( two conc5tric p>ts ( v unequal d5sity1 ! int]nal "p be+ a d>k sph]ical mass1 ! ext]nal a v ext5sive atmosph]e1 at a c]ta9 height 9 :i* !re is a /ratum ( lum9\s cl\ds :i* con/itutes ! photosph]e ( ! sun2 above ?is rises 8 real atmosph]e1 s r>e z to be only visible z a :ite aureola or corona dur+ total & annul> eclipses4 ,m4 ,faye conceives t f ! c5tral mass gase\s eruptions issue1 :i* =m ! spots by dissipat+ & p>tly ext+ui%+ ! lum9\s cl\ds1 & !n ris+ into ! r>e atmosph]e above t !y appe> z rose-col\r$ protub]ances dur+ annul> eclipses4 ,he e/imates t ! volume ( ^! vap\rs sometimes surpasses t ( ! e>? a ?\s& or ev5 two ?\s& times4 ,sir ,william ,h]s*el attribut$ ! spots to occasional op5+s 9 ! lum9\s coat+1 :i* seems to be always 9 motion2 b :atev] ! cause ( ! spots may be1 x is c]ta9ly p]iodical4 ,! :ite corona & beads 7 se5 dur+ ! eclipse ( ! #ae? ,m>*1 #aheh1 b !re 7 no rose-col\r$ appe>ances1 9 ,engl& at lea/2 b ! sky 0 cl\d$1 s t ! eclipse 0 only visible at int]vals4 ,planets sometimes eclipse "o ano!r4 ,on ! #ag? ( ,may1 #agcg1 ,m]cury 0 eclips$ by ,v5us ne> _! inf]ior conjunction2 ,m>s pass$ ov] ,jupit] on ! #i? ( ,janu>y1 #aeia2 & on ! #cj? ( ,octob]1 #ahbe1 ! moon eclips$ ,saturn4 ,^! ph5om5a1 h[ev]1 happ5 v seldom1 because all ! planets1 or ev5 a "p ( !m1 are v r>ely se5 9 conjunction at once2 t is1 9 ! same "p ( ! heav5s at ! same "t4 ,m ?an #bejj ye>s be=e our era ! five great planets 7 9 conjunction4 ,on ! #ae? ( ,septemb]1 #aahf1 a simil> assemblage took place betwe5 ! con/ellations ( ,virgo & ,libra2 & 9 #ahja ! ,moon1 ,jupit]1 ,saturn1 & ,v5us 7 unit$ 9 ! he>t ( ! ,lion4 ,^! conjunctions are s r>e1 t ,lal&e has comput$ t m ?an sev5te5 millions ( millions ( ye>s sep>ate ! epo*s ( ! contemporane\s conjunctions ( ! six great planets4 ,! motions ( ! moon h n[ become ( m importance to ! navigator & geograph] ?an ^? ( any o!r heav5ly body1 f ! precision ) :i* t]re/rial longitude is det]m9$ by occultations ( />s1 & by lun> di/ances4 ,9 consequ5ce ( ! retrograde motion ( ! nodes ( ! lun> orbit1 at ! rate ( #c #ajfd daily1 ^! po9ts make a t\r ( ! heav5s 9 a little m ?an eighte5 ye>s & a half4 ,?is causes ! moon to move r\nd ! e>? 9 a k9d ( spiral1 s t h] disc at diff]5t times passes ov] e po9t 9 a zone ( ! heav5s ext5d+ r m ?an #e #i on ea* side ( ! ecliptic4 ,x is !re=e evid5t t at "o "t or o!r %e mu/ eclipse e /> & planet %e meets ) 9 ?is space4 ,!re=e ! occultation ( a /> by ! moon is a ph5om5on ( frequ5t occurr5ce4 ,! moon seems to pass ov] ! />1 :i* almo/ in/antane\sly vani%es at "o side ( h] disc1 & aft] a %ort "t z sudd5ly reappe>s on ! o!r4 ,a lun> di/ance is ! obs]v$ di/ance ( ! moon f ! sun1 or f a p>ticul> /> or planet1 at any in/ant4 ,! lun> !ory is br\ght to su* p]fection1 t ! times ( ^! ph5om5a1 obs]v$ "u any m]idian1 :5 comp>$ ) ^? comput$ = t ( ,gre5wi*1 & giv5 9 ! ,nautical ,almanac1 furni% ! longitude ( ! obs]v] )9 a few miles 7,n4 #ie47 ,f ! lun> !ory1 ! mean di/ance ( ! sun f ! e>?1 & !nce ! :ole dim5sions ( ! sol> sy/em1 are kn[n2 = ! =ces :i* reta9 ! e>? & moon 9 _! orbits are respectively proportional to ! radii vectores ( ! e>? & moon1 ea* be+ divid$ by ! squ>e ( its p]iodic "t4 ,&1 z ! lun> !ory gives ! ratio ( ! =ces1 ! ratio ( ! di/ances ( ! sun & moon f ! e>? is obta9$4 ,h5ce x appe>s t ! sun's mean di/ance f ! e>? is #ciig or ne>ly #djj times great] ?an t ( ! moon4 ,! me?od ( f9d+ ! absolute di/ances ( ! cele/ial bodies1 9 miles1 is 9 fact ! same ) t employ$ 9 measur+ ! di/ances ( t]re/rial objects4 ,f ! extremities ( a kn[n base 7,n4 #aaf71 ! angles :i* ! visual rays f ! object =m ) x are measur$2 _! sum subtract$ f two "r angles gives ! angle opposite ! base2 !re=e1 by trigonometry1 all ! angles & sides ( ! triangle may be comput$--consequ5tly ! di/ance ( ! object is f\nd4 ,! angle "u :i* ! base ( ! triangle is se5 f ! object is ! p>allax ( t object4 ,x evid5tly increases & decreases ) ! di/ance4 ,!re=e ! base mu/ be v great inde$ to be visible f ! cele/ial bodies4 ,! globe itself1 ^: dim5sions are obta9$ by actual admeasurem5t1 furni%es a /&>d ( measures ) :i* we comp>e ! di/ances1 masses1 d5sities1 & volumes ( ! sun & planets4 ,,section ,,vi4 ,=m ( ! ,e>? & ,planets--,figure ( a ,homog5e\s ,sph]oid 9 ,rotation--,figure ( a ,sph]oid ( v>iable ,d5sity--,figure ( ! ,e>?1 suppos+ x to be an ,ellipsoid ( ,revolution--,m5suration ( a ,degree ( ! ,m]idian--,compression & ,size ( ! ,e>? f ,degrees ( ,m]idian--,figure ( ,e>? f ! ,p5dulum4 ,,! !oretical inve/igation ( ! figure ( ! e>? & planets is s complicat$1 t nei!r ! geometry ( ,newton1 nor ! ref9$ analysis ( ,la ,place1 has atta9$ m ?an an approximation4 ,! solution ( t difficult problem has be5 accompli%$ by our di/+ui%$ c\ntryman ,mr4 ,ivory4 ,! inve/igation has be5 conduct$ by successive /eps1 beg9n+ ) a simple case1 & !n proce$+ to ! m difficult4 ,b1 9 all1 ! =ces :i* occasion ! revolutions ( ! e>? & planets are omitt$1 because1 by act+ equally ^u all ! p>ticles1 !y d n di/urb _! mutual relations4 ,a fluid mass ( uni=m d5sity1 ^: p>ticles mutually gravitate to ea* o!r1 w assume ! =m ( a sph]e :5 at re/4 ,b1 if ! sph]e beg9s to revolve1 e p>ticle w describe a circle 7,n4 #aag71 hav+ its c5tre 9 ! axis ( revolution4 ,! planes ( all ^! circles w be p>allel to "o ano!r & p]p5dicul> to ! axis1 & ! p>ticles w h a t5d5cy to fly f t axis 9 consequ5ce ( ! c5trifugal =ce aris+ f ! velocity ( rotation4 ,! =ce ( gravity is ev]y:]e p]p5dicul> to ! surface 7,n4 #aah71 & t5ds to ! int]ior ( ! fluid mass2 :]eas ! c5trifugal =ce acts p]p5dicul>ly to ! axis ( rotation1 & is direct$ to ! ext]ior4 ,&1 z its int5sity dim9i%es ) ! di/ance f ! axis ( rotation1 x decreases f ! equator to ! poles1 :]e x ceases4 ,n[ x is cle> t ^! two =ces are 9 direct opposition to ea* o!r 9 ! equator alone1 & t gravity is !re dim9i%$ by ! :ole effect ( ! c5trifugal =ce1 :]eas1 9 e o!r "p ( ! fluid1 ! c5trifugal =ce is resolv$ into two p>ts1 "o ( :i*1 be+ p]p5dicul> to ! surface1 dim9i%es ! =ce ( gravity2 b ! o!r1 be+ at a tang5t to ! surface1 urges ! p>ticles t[>ds ! equator1 :]e !y accumulate till _! numb]s comp5sate ! dim9ution ( gravity1 :i* makes ! mass bulge at ! equator1 & become flatt5$ at ! poles4 ,x appe>s1 !n1 t ! influ5ce ( ! c5trifugal =ce is mo/ p[]ful at ! equator1 n only because x is actually great] !re ?an else:]e1 b because its :ole effect is employ$ 9 dim9i%+ gravity1 :]eas1 9 e o!r po9t ( ! fluid mass1 x is only a "p t is s employ$4 ,= bo? ^! reasons1 x gradually decreases t[>ds ! poles1 :]e x ceases4 ,on ! contr>y1 gravity is lea/ at ! equator1 because ! p>ticles are f>!r f ! c5tre ( ! mass1 & increases t[>ds ! poles1 :]e x is greate/4 ,x is evid5t1 !re=e1 t1 z ! c5trifugal =ce is mu* less ?an ! =ce ( gravity--gravitation1 :i* is ! diff]5ce betwe5 ! two1 is lea/ at ! equator1 & cont9ually increases t[>ds ! poles1 :]e x is a maximum4 ,on ^! pr9ciples ,sir ,isaac ,newton prov$ t a homog5e\s fluid 7,n4 #aai7 mass 9 rotation assumes ! =m ( an ellipsoid ( revolution 7,n4 #abj71 ^: compression is #a_/bcj4 ,su*1 h[ev]1 _c be ! =m ( ! e>?1 because ! /rata increase 9 d5sity t[>ds ! c5tre4 ,! lun> inequalities also prove ! e>? to be s con/ruct$2 x 0 requisite1 !re=e1 to consid] ! fluid mass to be ( v>iable d5sity4 ,includ+ ?is condition1 x has be5 f\nd t ! mass1 :5 9 rotation1 w\ld /ill assume ! =m ( an ellipsoid ( revolution 7,n4 #abj72 t ! p>ticles ( equal d5sity w\ld arrange !mselves 9 conc5tric elliptical /rata 7,n4 #aba71 ! mo/ d5se be+ 9 ! c5tre2 b t ! compression or flatt5+ w\ld be less ?an 9 ! case ( ! homog5e\s fluid4 ,! compression is /ill less :5 ! mass is consid]$ to be1 z x actually is1 a solid nucleus1 decreas+ regul>ly 9 d5sity f ! c5tre to ! surface1 & p>tially cov]$ by ! ocean1 because ! solid p>ts1 by _! cohesion1 ne>ly de/roy t "p ( ! c5trifugal =ce :i* gives ! p>ticles a t5d5cy to accumulate at ! equator1 ?\gh n altoge!r2 o!rwise ! sea1 by ! sup]ior mobility ( its p>ticles1 w\ld fl[ t[>ds ! equator & leave ! poles dry4 ,besides1 x is well kn[n t ! cont95ts at ! equator are m elevat$ ?an !y are 9 high] latitudes4 ,x is also necess>y = ! equilibrium ( ! ocean t its d5sity %\ld be less ?an ! mean d5sity ( ! e>?1 o!rwise ! cont95ts w\ld be p]petually liable to inundations f /orms & o!r causes4 ,on ! :ole1 x appe>s f !ory1 t a horizontal l9e pass+ r\nd ! e>? ?r\gh bo? poles mu/ be ne>ly an ellipse1 hav+ its major axis 9 ! plane ( ! equator1 & its m9or axis co9cid5t ) ! axis ( ! e>?'s rotation 7,n4 #abb74 ,x is easy to %[1 9 a sph]oid ^: /rata are elliptical1 t ! increase 9 ! l5g? ( ! radii 7,n4 #abc71 ! decrease ( gravitation1 & ! increase 9 ! l5g? ( ! arcs ( ! m]idian1 correspond+ to angles ( "o degree1 f ! poles to ! equator1 are all proportional to ! squ>e ( ! cos9e ( ! latitude 7,n4 #abd74 ,^! quantities are s connect$ ) ! ellipticity ( ! sph]oid1 t ! total increase 9 ! l5g? ( ! radii is equal to ! compression or flatt5+1 & ! total dim9ution 9 ! l5g? ( ! arcs is equal to ! compression1 multipli$ by ?ree times ! l5g? ( an arc ( "o degree at ! equator4 ,h5ce1 by measur+ ! m]idian curvature ( ! e>?1 ! compression1 & consequ5tly its figure1 become kn[n4 ,?is1 inde$1 is assum+ ! e>? to be an ellipsoid ( revolution2 b ! actual measurem5t ( ! globe w %[ h[ f> x corresponds ) t solid 9 figure & con/itution4 ,! c\rses ( ! great riv]s1 :i* are 9 g5]al navigable to a consid]able ext5t1 prove t ! curvature ( ! l& diff]s b little f t ( ! ocean2 &1 z ! heights ( ! m\nta9s & cont95ts are inconsid]able :5 comp>$ ) ! magnitude ( ! e>?1 its figure is und]/ood to be det]m9$ by a surface at e po9t p]p5dicul> to ! direction ( gravitation1 or ( ! plumb-l9e1 & is ! same :i* ! sea w\ld h if x 7 cont9u$ all r\nd ! e>? b5ea? ! cont95ts4 ,su* is ! figure t has be5 measur$ 9 ! foll[+ mann]3-- ,a t]re/rial m]idian is a l9e pass+ ?r\gh bo? poles1 all ! po9ts ( :i* h _! noon contemporane\sly4 ,7 ! l5g?s & curvatures ( diff]5t m]idians kn[n1 ! figure ( ! e>? might be det]m9$4 ,b ! l5g? ( "o degree is suffici5t to give ! figure ( ! e>?1 if x be measur$ on diff]5t m]idians1 & 9 a v>iety ( latitudes4 ,=1 if ! e>? 7 a sph]e1 all degrees w\ld be ( ! same l5g?2 b1 if n1 ! l5g?s ( ! degrees w\ld be great]1 exactly 9 proportion z ! curvature is less4 ,a comp>ison ( ! l5g? ( a degree 9 diff]5t p>ts ( ! e>?'s surface w !re=e det]m9e its size & =m4 ,an arc ( ! m]idian may be measur$ by det]m9+ ! latitude ( its extreme po9ts by a/ronomical obs]vations 7,n4 #abe71 & !n measur+ ! di/ance betwe5 !m 9 feet or fa?oms4 ,! di/ance ?us det]m9$ on ! surface ( ! e>?1 divid$ by ! degrees & p>ts ( a degree conta9$ 9 ! diff]5ce ( ! latitudes1 w give ! exact l5g? ( "o degree1 ! diff]5ce ( ! latitudes be+ ! angle conta9$ betwe5 ! v]ticals at ! extremities ( ! arc4 ,?is w\ld be easily accompli%$ 7 ! di/ance unob/ruct$ & on a level ) ! sea4 ,b1 on acc\nt ( ! innum]able ob/acles on ! surface ( ! e>?1 x is necess>y to connect ! extreme po9ts ( ! arc by a s]ies ( triangles 7,n4 #abf71 ! sides & angles ( :i* are ei!r measur$ or comput$1 s t ! l5g? ( ! arc is asc]ta9$ ) mu* labori\s calculation4 ,9 consequ5ce ( ! irregul>ities ( ! surface ea* triangle is 9 a diff]5t plane4 ,!y mu/ !re=e be r$uc$ by computation to :at !y w\ld h be5 _h !y be5 measur$ on ! surface ( ! sea4 ,&1 z ! e>? may 9 ?is case be e/eem$ sph]ical1 !y require a correction to r$uce !m to sph]ical triangles4 ,! (fic]s :o conduct$ ! trigonometrical survey1 9 measur+ #ejj feet ( a base 9 ,irel& twice ov]1 f\nd t ! diff]5ce 9 ! two measurem5ts did n am\nt to ! #hjj? "p ( an in*2 & 9 ! ,g5]al ,survey ( ,great ,brita91 five bases 7 measur$ f #e to #g miles long1 & "s ( !m #djj miles ap>t1 yet1 :5 connect$ by s]ies ( triangles1 ! measur$ & comput$ l5g?s did n diff] by m ?an #c in*es1 an unp>allel$ degree ( accuracy2 b su* is ! accuracy ) :i* ^! op]ations are conduct$4 ,arcs ( ! m]idian h be5 measur$ 9 a v>iety ( latitudes 9 bo? hemisph]es1 z well z arcs p]p5dicul> to ! m]idian4 ,f ^! measurem5ts x appe>s t ! l5g? ( ! degrees increases f ! equator to ! poles1 ne>ly 9 proportion to ! squ>e ( ! s9e ( ! latitude 7,n4 #abg74 ,consequ5tly1 ! convexity ( ! e>? dim9i%es f ! equator to ! poles4 ,7 ! e>? an ellipsoid ( revolution1 ! m]idians w\ld be ellipses ^: less] axes w\ld co9cide ) ! axis ( rotation1 & all ! degrees measur$ betwe5 ! pole & ! equator w\ld give ! same compression :5 comb9$ two & two4 ,t1 h[ev]1 is f> f be+ ! case4 ,sc>cely any ( ! measurem5ts give exactly ! same results1 *iefly on acc\nt ( local attractions1 :i* cause ! plumb-l9e to deviate f ! v]tical4 ,! vic9ity ( m\nta9s produces t effect4 ,"o ( ! mo/ rem>kable anomalies ( ?is k9d has be5 obs]v$ 9 c]ta9 localities ( nor!rn ,italy1 :]e ! action ( "s d5se subt]rane\s matt] causes ! plumb-l9e to deviate sev5 or eight times m ?an x did f ! attraction ( ,*imborazo1 9 ! obs]vations ( ,b\gu]1 :ile measur+ a degree ( ! m]idian at ! equator4 ,9 consequ5ce ( ?is local attraction1 ! degrees ( ! m]idian 9 t "p ( ,italy seem to increase t[>ds ! equator ?r\gh a small space1 in/ead ( decreas+1 z if ! e>? 0 drawn out at ! poles1 in/ead ( be+ flatt5$4 ,_m o!r discrepancies occur1 b f ! mean ( ! five pr9cipal measurem5ts ( arcs 9 ,p]u1 ,india1 ,france1 ,engl&1 & ,lapl&1 ,mr4 ,ivory has d$uc$ t ! figure :i* mo/ ne>ly foll[s ?is law is an ellipsoid ( revolution ^: equatorial radius is #cifbhbd miles1 & ! pol> radius #cidiehe miles4 ,! diff]5ce1 or #acbci miles1 divid$ by ! equatorial radius1 is #a_/bii ne>ly#c 7,n4 #abh74 ,?is fraction is call$ ! compression ( ! e>?1 & does n diff] mu* f t giv5 by ! lun> inequalities4 ,s9ce ! prec$+ quantities 7 det]m9$1 arcs ( ! m]idian h be5 measur$ 9 v>i\s p>ts ( ! globe1 ( :i* ! mo/ ext5sive are ! ,russian arc ( #be #bj betwe5 ! ,glacial ,sea & ! ,danube1 conduct$ "u ! sup]9t5d5ce ( ,m4 ,/ruve1 & ! ,indian arc ext5d$ to #ba #ba1 by ,colonel ,ev]e/4 ,! compression d$uc$ by ,bessel f ! sum ( t5 arcs is #bih-c_/d1 ! equatorial radius #cifbhjb1 & ! pol> #cidieed miles1 :il/ ,mr4 ,airy arrives at an almo/ id5tical result 7#cifbhbd1 #cidiehe1 & #bih-hc_/ajj7 f a consid]ation ( all ! arcs1 measur$ up to #ahca1 includ+ ! great ,indian & ,russian ones4 ,if we assume ! e>? to be a sph]e1 ! l5g? ( a degree ( ! m]idian is #fi-ad_/ajj ,engli% miles4 ,!re=e #cfj degrees1 or ! :ole equatorial circumf]5ce ( ! globe1 is #bd1hii ,engli% miles4 ,erato/h5es1 :o di$ #aid ye>s be=e ! ,*ri/ian era1 0 ! fir/ to give an approximate value ( ! e>?'s circumf]5ce1 by ! measurem5t ( an arc betwe5 ,alex&ria & ,sy5e4 ,!re is ano!r me?od ( f9d+ ! figure ( ! e>?1 totally diff]5t f ! prec$+1 solely dep5d+ ^u ! increase ( gravitation f ! equator to ! poles4 ,! =ce ( gravitation at any place is measur$ by ! desc5t ( a heavy body dur+ ! fir/ second ( its fall4 ,& ! int5sity ( ! c5trifugal =ce is measur$ by ! deflection ( any po9t f ! tang5t 9 a second4 ,=1 s9ce ! c5trifugal =ce balances ! attraction ( ! e>?1 x is an exact measure ( ! gravitat+ =ce4 ,7 ! attraction to cease1 a body on ! surface ( ! e>? w\ld fly (f 9 ! tang5t by ! c5trifugal =ce1 in/ead ( b5d+ r\nd 9 ! circle ( rotation4 ,!re=e1 ! deflection ( ! circle f ! tang5t 9 a second measures ! int5sity ( ! e>?'s attraction1 & is equal to ! v]s$ s9e ( ! arc describ$ dur+ t "t1 a quantity easily det]m9$ f ! kn[n velocity ( ! e>?'s rotation4 ,:5ce x has be5 f\nd t at ! equator ! c5trifugal =ce is equal to ! #bhi? "p ( gravity4 ,n[1 x is prov$ by analysis t1 :atev] ! con/itution ( ! e>? & planets may be1 if ! int5sity ( gravitation at ! equator be tak5 equal to unity1 ! sum ( ! compression ( ! ellipsoid1 & ! :ole increase ( gravitation f ! equator to ! pole1 is equal to five halves ( ! ratio ( ! c5trifugal =ce to gravitation at ! equator4 ,?is quantity ) reg>d to ! e>? is #e_/b ( #a_/bhi or #a_/aaeb4 ,consequ5tly1 ! compression ( ! e>? is equal to #a_/aaeb dim9i%$ by ! :ole increase ( gravitation4 ,s t its =m w be kn[n1 if ! :ole increase ( gravitation f ! equator to ! pole c be det]m9$ by exp]im5t4 ,?is has be5 accompli%$ by a me?od f\nd$ ^u ! foll[+ consid]ations3--,if ! e>? 7 a homog5e\s sph]e )\t rotation1 its attraction on bodies at its surface w\ld be ev]y:]e ! same4 ,if x be elliptical & ( v>iable d5sity1 ! =ce ( gravity1 !oretically1 ought to increase f ! equator to ! pole1 z unity plus a con/ant quantity multipli$ into ! squ>e ( ! s9e ( ! latitude 7,n4 #abg74 ,b = a sph]oid 9 rotation ! c5trifugal =ce v>ies1 by ! laws ( me*anics1 z ! squ>e ( ! s9e ( ! latitude1 f ! equator1 :]e x is greate/1 to ! pole1 :]e x vani%es4 ,&1 z x t5ds to make bodies fly (f ! surface1 x dim9i%es ! =ce ( gravity by a small quantity4 ,h5ce1 by gravitation1 :i* is ! diff]5ce ( ^! two =ces1 ! fall ( bodies ought to be accel]at$ f ! equator to ! poles proportionably to ! squ>e ( ! s9e ( ! latitude2 & ! weight ( ! same body ought to increase 9 t ratio4 ,?is is directly prov$ by ! oscillations ( ! p5dulum 7,n4 #abi71 :i*1 9 fact1 is a fall+ body2 =1 if ! fall ( bodies be accel]at$1 ! oscillations w be m rapid3 9 ord]1 !re=e1 t !y may always be p]=m$ 9 ! same "t1 ! l5g? ( ! p5dulum mu/ be alt]$4 ,by num]\s & c>eful exp]im5ts x is prov$ t a p5dulum1 :i* oscillates #hf1djj times 9 a mean day at ! equator1 w d ! same at e po9t ( ! e>?'s surface1 if its l5g? be increas$ progressively to ! pole1 z ! squ>e ( ! s9e ( ! latitude4 ,f ! mean ( ^! x appe>s t ! :ole decrease ( gravitation f ! poles to ! equator is #jjjeaddi1 :i*1 subtract$ f #a_/aaeb1 %[s t ! compression ( ! t]re/rial sph]oid is ab\t #a_/bhebf4 ,?is value has be5 d$uc$ by ! late ,mr4 ,baily1 presid5t ( ! ,a/ronomical ,society1 :o devot$ mu* att5tion to ?is subject2 at ! same "t1 x may be obs]v$ t no two sets ( p5dulum exp]im5ts give ! same result1 probably f local attractions4 ,! compression obta9$ by ?is me?od does n diff] mu* f t giv5 by ! lun> inequalities1 nor f ! arcs 9 ! direction ( ! m]idian1 & ^? p]p5dicul> to x4 ,! ne> co9cid5ce ( ^! ?ree values1 d$uc$ by me?ods s entirely indep5d5t ( ea* o!r1 %[s t ! mutual t5d5cies ( ! c5tres ( ! cele/ial bodies to "o ano!r1 & ! attraction ( ! e>? = bodies at its surface1 result f ! reciprocal attraction ( all _! p>ticles4 ,ano!r pro( may be add$4 ,! nutation ( ! e>?'s axis & ! precession ( ! equ9oxes 7,n4 #adf7 are occasion$ by ! action ( ! sun & moon on ! protub]ant matt] at ! e>?'s equator4 ,&1 al?\gh ^! inequalities d n give ! absolute value ( ! t]re/rial compression1 !y %[ t ! fraction express+ x is compris$ betwe5 ! limits #a_/bgi & #a_/egc4 ,x might be expect$ t ! same compression %\ld result f ea*1 if ! diff]5t me?ods ( obs]vation c\ld be made )\t error4 ,?is1 h[ev]1 is n ! case2 = aft] all[ance has be5 made = e cause ( error1 su* discrepancies are f\nd1 bo? 9 ! degrees ( ! m]idian & 9 ! l5g? ( ! p5dulum1 z %[ t ! figure ( ! e>? is v complicat$4 ,b !y are s small1 :5 comp>$ ) ! g5]al results1 t !y may be disreg>d$4 ,! compression d$uc$ f ! mean ( ! :ole appe>s n to diff] mu* f #a_/cjj2 t giv5 by ! lun> !ory has ! advantage ( be+ indep5d5t ( ! irregul>ities ( ! e>?'s surface & ( local attractions4 ,! regul>ity ) :i* ! obs]v$ v>iation 9 ! l5g? ( ! p5dulum foll[s ! law ( ! squ>e ( ! s9e ( ! latitude proves ! /rata to be elliptical1 & symmetrically dispos$ r\nd ! c5tre ( gravity ( ! e>?1 :i* af=ds a /rong presumption 9 fav\r ( its orig9al fluidity4 ,x is rem>kable h[ little influ5ce ! sea has on ! v>iation ( ! l5g?s ( ! arcs ( ! m]idian1 or on gravitation2 nei!r does x mu* affect ! lun> inequalities1 f its d5sity be+ only ab\t a fif? ( ! mean d5sity ( ! e>?4 ,=1 if ! e>? 7 to become fluid1 aft] be+ /ripp$ ( ! ocean1 x w\ld assume ! =m ( an ellipsoid ( revolution ^: compression is #a_/cjdh1 :i* diff]s v little f t det]m9$ by obs]vation1 & proves1 n only t ! d5sity ( ! ocean is inconsid]able1 b t its mean dep? is v small4 ,!re are pr(\nd cavities 9 ! bottom ( ! sea1 b its mean dep? probably does n mu* exce$ ! mean height ( ! cont95ts & isl&s above its level4 ,on ?is acc\nt1 imm5se tracts ( l& may be des]t$ or ov]:elm$ by ! ocean1 z appe>s really to h be5 ! case1 )\t any great *ange 9 ! =m ( ! t]re/rial sph]oid4 ,! v>iation 9 ! l5g? ( ! p5dulum 0 fir/ rem>k$ by ,ri*t] 9 #afgb1 :ile obs]v+ transits ( ! fix$ />s across ! m]idian at ,cay5ne1 ab\t five degrees nor? ( ! equator4 ,he f\nd t 8 clock lo/ at ! rate ( #bm #bhs daily1 :i* induc$ him to det]m9e ! l5g? ( a p5dulum beat+ seconds 9 t latitude2 &1 repeat+ ! exp]im5ts on 8 return to ,europe1 he f\nd ! seconds' p5dulum at ,p>is to be m ?an ! twelf? ( an in* long] ?an t at ,cay5ne4 ,! =m & size ( ! e>? be+ det]m9$1 a /&>d ( measure is furni%$ ) :i* ! dim5sions ( ! sol> sy/em may be comp>$4 ,,section ,,vii4 ,p>allax--,lun> ,p>allax f\nd f ,direct ,obs]vation--,sol> ,p>allax d$uc$ f ! ,transit ( ,v5us--,di/ance ( ! ,sun f ! ,e>?--,annual ,p>allax--,di/ance ( ! ,fix$ ,/>s4 ,,! p>allax ( a cele/ial body is ! angle "u :i* ! radius ( ! e>? w\ld be se5 if view$ f ! c5tre ( t body2 x af=ds ! means ( asc]ta9+ ! di/ances ( ! sun1 moon1 & planets 7,n4 #acj74 ,:5 ! moon is 9 ! horizon at ! in/ant ( ris+ or sett+1 suppose l9es to be drawn f h] c5tre to ! spectator & to ! c5tre ( ! e>?3 ^! w\ld =m a "r-angl$ triangle ) ! t]re/rial radius1 :i* is ( a kn[n l5g?2 &1 z ! p>allax or angle at ! moon c be measur$1 all ! angles & "o side are giv52 :5ce ! di/ance ( ! moon f ! c5tre ( ! e>? may be comput$4 ,! p>allax ( an object may be f\nd1 if two obs]v]s "u ! same m]idian1 b at a v great di/ance f "o ano!r1 obs]ve its z5i? di/ances on ! same day at ! "t ( its passage ov] ! m]idian4 ,by su* contemporane\s obs]vations at ! ,cape ( ,good ,hope & at ,b]l91 ! mean horizontal p>allax ( ! moon 0 f\nd to be #cdei1 :5ce ! mean di/ance ( ! moon is ab\t sixty times ! greate/ t]re/rial radius1 or #bcg1fjh miles ne>ly4#d ,s9ce ! p>allax is equal to ! radius ( ! e>? divid$ by ! di/ance ( ! moon1 x v>ies ) ! di/ance ( ! moon f ! e>? "u ! same p>allel ( latitude1 & proves ! ellipticity ( ! lun> orbit4 ,:5 ! moon is at h] mean di/ance1 x v>ies ) ! t]re/rial radii1 ?us %[+ t ! e>? is n a sph]e 7,n4 #aca74 ,al?\gh ! me?od describ$ is suffici5tly accurate = f9d+ ! p>allax ( an object z ne> z ! moon1 x w n answ] = ! sun1 :i* is s remote t ! smalle/ error 9 obs]vation w\ld lead to a false result4 ,b t difficulty is obviat$ by ! transits ( ,v5us4 ,:5 t planet is 9 h] nodes 7,n4 #acb71 or )9 #a-a_/d ( !m1 t is1 91 or ne>ly 91 ! plane ( ! ecliptic1 %e is occasionally se5 to pass ov] ! sun l a black spot4 ,if we c\ld imag9e t ! sun & ,v5us _h no p>allax1 ! l9e describ$ by ! planet on 8 disc1 & ! duration ( ! transit1 w\ld be ! same to all ! inhabitants ( ! e>?4 ,b1 z ! semi-diamet] ( ! e>? has a s5sible magnitude :5 view$ f ! c5tre ( ! sun1 ! l9e describ$ by ! planet 9 its passage ov] 8 disc appe>s to be ne>] to 8 c5tre1 or f>!r f x1 accord+ to ! position ( ! obs]v]2 s t ! duration ( ! transit v>ies ) ! diff]5t po9ts ( ! e>?'s surface at :i* x is obs]v$ 7,n4 #acc74 ,?is diff]5ce ( "t1 be+ entirely ! effect ( p>allax1 furni%es ! means ( comput+ x f ! kn[n motions ( ! e>? & ,v5us1 by ! same me?od z = ! eclipses ( ! sun4 ,9 fact1 ! ratio ( ! di/ances ( ,v5us & ! sun f ! e>? at ! "t ( ! transit is kn[n f ! !ory ( _! elliptical motion4 ,consequ5tly ! ratio ( ! p>allaxes ( ^! two bodies1 be+ inv]sely z _! di/ances1 is giv52 & z ! transit gives ! diff]5ce ( ! p>allaxes1 t ( ! sun is obta9$4 ,9 #agfi ! p>allax ( ! sun 0 det]m9$ by obs]vations ( a transit ( ,v5us made at ,w>dhus 9 ,lapl&1 & at ,tahiti 9 ! ,s\? ,sea4 ,! latt] obs]vation 0 ! object ( ,cook's fir/ voyage4 ,! transit la/$ ab\t six h\rs at ,tahiti1 & ! diff]5ce 9 duration at ^! two /ations 0 eight m9utes2 :5ce ! sun's horizontal p>allax 0 f\nd to be #hgb4 ,b by o!r consid]ations x has be5 r$uc$ by ,pr(essor ,encke to #heggf2 f :i* ! mean di/ance ( ! sun appe>s to be ab\t n9ety-five millions ( miles4 ,?is is confirm$ by an inequality 9 ! motion ( ! moon1 :i* dep5ds ^u ! p>allax ( ! sun1 & :i*1 :5 comp>$ ) obs]vation1 gives #hf = ! sun's p>allax4 ,! transits ( ,v5us 9 #ahgd & #ahhb w be unfav\rable = asc]ta9+ ! accuracy ( ! sol> p>allax1 & no o!r transit ( t planet w take place till ! tw5ty-fir/ c5tury2 b 9 ! mean "t rec\rse may be _h to ! oppositions ( ,m>s4 ,! p>allax ( ,v5us is det]m9$ by h] transits2 t ( ,m>s by direct obs]vation1 & x is f\nd to be ne>ly d\ble t ( ! sun1 :5 ! planet is 9 opposition4 ,! di/ance ( ^! two planets f ! e>? is !re=e kn[n 9 t]re/rial radii1 consequ5tly _! mean di/ances f ! sun may be comput$2 & z ! ratios ( ! di/ances ( ! planets f ! sun are kn[n by ,kepl]'s law1 ( ! squ>es ( ! p]iodic times ( any two planets be+ z ! cubes ( _! mean di/ances f ! sun1 _! absolute di/ances 9 miles are easily f\nd 7,n4 #acd74 ,?is law is v rem>kable1 9 ?us unit+ all ! bodies ( ! sy/em1 & ext5d+ to ! satellites z well z ! planets4 ,f> z ! e>? seems to be f ! sun1 ,uranus is no less ?an n9ete51 & ,neptune ?irty times f>!r4 ,situate on ! v]ge ( ! sy/em1 ! sun mu/ appe> f ,uranus n mu* l>g] ?an ,v5us does to u1 & f ,neptune z a /> ( ! fif? magnitude4 ,! e>? _c ev5 be visible z a telescopic object to a body s remote z ei!r ,uranus or ,neptune4 ,yet man1 ! inhabitant ( ! e>?1 so>s beyond ! va/ dim5sions ( ! sy/em to :i* 8 planet belongs1 & assumes ! diamet] ( its orbit z ! base ( a triangle ^: apex ext5ds to ! />s4 ,sublime z ! idea is1 ?is assumption proves ineffectual1 except 9 a v few cases2 = ! app>5t places ( ! fix$ />s are n s5sibly *ang$ by ! e>?'s annual revolution4 ,) ! aid d]iv$ f ! ref9em5ts ( mod]n a/ronomy1 & ( ! mo/ p]fect in/rum5ts1 a s5sible p>allax has be5 detect$ only 9 a v few ( ^! remote suns4 ,c5tauri has a p>allax ( "o second ( space1 !re=e x is ! ne>e/ kn[n />1 & yet x is m ?an two hundr$ ?\s& times f>!r f u ?an ! sun is4 ,at su* a di/ance n only ! t]re/rial orbit %r9ks to a po9t1 b ! :ole sol> sy/em1 se5 9 ! focus ( ! mo/ p[]ful telescope1 might be eclips$ by ! ?ickness ( a spid]'s ?read4 ,light1 fly+ at ! rate ( #aij1jjj miles 9 a second1 w\ld take m ?an ?ree ye>s to travel ov] t space4 ,"o ( ! ne>e/ />s may !re=e h be5 k9dl$ or ext+ui%$ m ?an ?ree ye>s be=e we c\ld h be5 aw>e ( s mighty an ev5t4 ,b ?is di/ance mu/ be small :5 comp>$ ) t ( ! mo/ remote ( ! bodies :i* are visible 9 ! heav5s4 ,! fix$ />s are und\bt$ly lum9\s l ! sun3 x is !re=e probable t !y are n ne>] to "o ano!r ?an ! sun is to ! ne>e/ ( !m4 ,9 ! milky way & ! o!r />ry nebul1 "s ( ! />s t seem to u to be close to o!rs may be f> beh9d !m 9 ! b\ndless dep? ( space2 nay1 may be rationally suppos$ to be situate _m ?\s& times f>!r (f4 ,light w\ld !re=e require ?\s&s ( ye>s to come to ! e>? f ^? myriads ( suns ( :i* our own is b 8! remote companion40 ,,section ,,viii4 ,masses ( ,planets t h no ,satellites det]m9$ f _! ,p]turbations--,masses ( ! o!rs obta9$ f ! ,motions ( _! ,satellites--,masses ( ! ,sun1 ! ,e>?1 ( ,jupit] & ( ! ,jovial ,sy/em--,mass ( ! ,moon--,real ,diamet]s ( ,planets1 h[ obta9$--,size ( ,sun1 ,d5sities ( ! ,heav5ly ,bodies--,=mation ( ,a/ronomical ,tables--,requisite ,data & ,means ( obta9+ !m4 ,,! masses ( su* planets z h no satellites are kn[n by comp>+ ! inequalities !y produce 9 ! motions ( ! e>? & ( ea* o!r1 det]m9$ !oretically1 ) ! same inequalities giv5 by obs]vation2 = ! di/urb+ cause mu/ necess>ily be proportional to ! effect x produces4 ,! masses ( ! satellites !mselves may also be comp>$ ) t ( ! sun by _! p]turbations4 ,?us1 x is f\nd1 f ! comp>ison ( a va/ numb] ( obs]vations ) ,la ,place's !ory ( ,jupit]'s satellites1 t ! mass ( ! sun is no less ?an #fe1jjj1jjj times great] ?an ! lea/ ( ^! moons4 ,b1 z ! quantities ( matt] 9 any two prim>y planets are directly z ! cubes ( ! mean di/ances at :i* _! satellites revolve1 & inv]sely z ! squ>es ( _! p]iodic times 7,n4 #ace71 ! mass ( ! sun & ( any planets :i* h satellites may be comp>$ ) ! mass ( ! e>?4 ,9 ?is mann] x is comput$ t ! mass ( ! sun is #ced1icf times t ( ! e>?2 :5ce ! great p]turbations ( ! moon1 & ! rapid motion ( ! p]igee & nodes ( h] orbit 7,n4 #acf74 ,ev5 ,jupit]1 ! l>ge/ ( ! planets1 has be5 f\nd by ,pr(essor ,airy to be #ajdghga times less ?an ! sun2 &1 inde$1 ! mass ( ! :ole ,jovial sy/em is n m ?an ! #ajedd? "p ( t ( ! sun4 ,s t ! mass ( ! satellites be>s a v small proportion to t ( _! prim>y4 ,! mass ( ! moon is det]m9$ f sev]al s\rces--f h] action on ! t]re/rial equator1 :i* occasions ! nutation 9 ! axis ( rotation2 f h] horizontal p>allax2 f an inequality %e produces 9 ! sun's longitude2 & f h] action on ! tides4 ,! ?ree fir/ quantities1 comput$ f !ory & comp>$ ) _! obs]v$ values1 give h] mass respectively equal to ! #a_/ga1 #a_/gdb1 & #a_/fib1 "p ( t ( ! e>?1 :i* d n diff] mu* f ea* o!r4 ,dr4 ,br9kley has f\nd x to be #a_/hj f ! con/ant ( lun> nutation3 b1 f ! moon's action 9 rais+ ! tides1 h] mass appe>s to be ab\t ! #a_/ge "p ( t ( ! e>?--a value t _c diff] mu* f ! tru?4 ,! app>5t diamet]s ( ! sun1 moon1 & planets are det]m9$ by measurem5t2 !re=e _! real diamet]s may be comp>$ ) t ( ! e>?2 = ! real diamet] ( a planet is to ! real diamet] ( ! e>?1 or #gibf miles1 z ! app>5t diamet] ( ! planet to ! app>5t diamet] ( ! e>? z se5 f ! planet1 t is1 to twice ! p>allax ( ! planet4 ,accord+ to ,bessel1 ! mean app>5t diamet] ( ! sun is #aibcfd1 & ) ! sol> p>allax #heggf1 x w be f\nd t ! diamet] ( ! sun is ab\t #hhf1hgg miles4 ,!re=e1 if ! c5tre ( ! sun 7 to co9cide ) ! c5tre ( ! e>?1 8 volume w\ld n only include ! orbit ( ! moon1 b w\ld ext5d ne>ly z f> aga92 = ! moon's mean di/ance f ! e>? is ab\t sixty times ! e>?'s equatorial radius1 or #bch1gic miles3 s t twice ! di/ance ( ! moon is #dgg1ehf miles1 :i* diff]s b little f ! sol> radius2 8 equatorial radius is probably n mu* less ?an ! major axis ( ! lun> orbit4 ,! diamet] ( ! moon is only #bafj miles2 & ,jupit]'s diamet] ( #hh1bjj miles is v mu* less ?an t ( ! sun2 ! diamet] ( ,pallas does n mu* exce$ #gi miles1 s t an inhabitant ( t planet1 9 "o ( our /eam c>riages1 might g r\nd 8 _w 9 a few h\rs4 ,! diamet]s ( ,lutetia & ,atalanta are only #h & #d miles respectively2 b ! :ole ( ! #ee telescopic planets are s small1 t _! unit$ mass is probably n m ?an ! fif? or six? "p ( t ( ! moon4 ,! d5sities ( bodies are proportional to _! masses1 divid$ by _! volumes4 ,h5ce1 if ! sun & planets be assum$ to be sph]es1 _! volumes w be z ! cubes ( _! diamet]s4 ,n[1 ! app>5t diamet]s ( ! sun & e>?1 at _! mean di/ance1 are #aibcf & #agaeeb1 & ! mass ( ! e>? is ! #ced1icf? "p ( t ( ! sun tak5 z ! unit4 ,x foll[s1 !re=e1 t ! e>? is f\r times z d5se z ! sun4 ,b ! sun is s l>ge t 8 attractive =ce w\ld cause bodies to fall ?r\gh ab\t #ccdfe feet 9 a second4 ,consequ5tly1 if he 7 habitable by human be+s1 !y w\ld be unable to move1 s9ce _! weight w\ld be ?irty times z great z x is "h4 ,a man ( mod]ate size w\ld weigh ab\t two tons at ! surface ( ! sun2 :]eas at ! surface ( "s ( ! new planets he w\ld be s light t x w\ld be impossible to /& /eady1 s9ce he w\ld only weigh a few p\nds4 ,! mean d5sity ( ! e>? has be5 det]m9$ by ! foll[+ me?od4 ,s9ce a comp>ison ( ! action ( two planets ^u a ?ird gives ! ratio ( ! masses ( ^! two planets1 x is cle> t1 if we c comp>e ! effect ( ! :ole e>? ) ! effect ( any "p ( x1 a comp>ison may be in/itut$ betwe5 ! mass ( ! :ole e>? & ! mass ( t "p ( x4 ,n[ a lead5 ball 0 weigh$ aga9/ ! e>? by comp>+ ! effects ( ea* ^u a p5dulum2 ! ne>ness ( ! small] mass mak+ x produce a s5sible effect z comp>$ ) t ( ! l>g]3 = by ! laws ( attraction ! :ole e>? mu/ be consid]$ z collect$ 9 its c5tre4 ,by ?is me?od x has be5 f\nd t ! mean d5sity ( ! e>? is #effj times great] ?an t ( wat] at ! temp]ature ( #fb ( ,fahr5heit's !rmomet]4 ,! late ,mr4 ,baily1 ^: accuracy z an exp]im5tal philosoph] is ackn[l$g$1 0 unremitt+ly occupi$ ne>ly f\r ye>s 9 accompli%+ ?is v important object4 ,9 ord] to asc]ta9 ! mean d5sity ( ! e>? /ill m p]fectly1 ,mr4 ,airy made a s]ies ( exp]im5ts to comp>e ! simultane\s oscillations ( two p5dulums1 "o at ! bottom ( ! ,h>ton coal-pit1 #abfj feet deep1 9 ,nor?umb]l&1 & ! o!r on ! surface ( ! e>? imm$iately above x4 ,! oscillations ( ! p5dulums 7 comp>$ ) an a/ronomical clock at ea* /ation1 & ! "t 0 in/antane\sly transmitt$ f "o to ! o!r by a telegraphic wire4 ,! oscillations 7 obs]v$ = m ?an #ajj h\rs cont9u\sly1 :5 x 0 f\nd t ! l[] p5dulum made #b-a_/b oscillations m 9 #bd h\rs ?an ! upp] "o4 ,! exp]im5t 0 repeat$ = ! same l5g? ( "t ) ! same result2 b on ?is occasion ! upp] p5dulum 0 tak5 to ! bottom ( ! m9e & ! l[] br\ght to ! surface4 ,f ! diff]5ce betwe5 ! oscillations at ! two /ations x appe>s t gravitation at ! bottom ( ! m9e exce$s t at ! surface by ! #a_/aiaij "p1 & t ! mean d5sity ( ! e>? is #fefe1 :i* is great] ?an t obta9$ by ,mr4 ,baily by #hi4 ,:ile employ$ on ! trigonometrical survey ( ,scotl&1 ,colonel ,james det]m9$ ! mean d5sity ( ! e>? to be #ecaf1 f a deviation ( ! plumb-l9e am\nt+ to #b1 caus$ by ! attraction ( ,ar?ur's ,seat & ! heights ea/ ( ,ed9burgh3 x agrees m ne>ly ) ! d5sity f\nd by ,mr4 ,baily ?an ) t d$uc$ f ,mr4 ,airy's exp]im5ts4 ,all ! planets & satellites appe> to be ( less d5sity ?an ! e>?4 ,! motions ( ,jupit]'s satellites %[ t 8 d5sity increases t[>ds 8 c5tre4 ,7 8 mass homog5e\s1 8 equatorial & pol> axes w\ld be 9 ! ratio ( #da to #cf1 :]eas !y are obs]v$ to be only z #da to #ch4 ,! s+ul> irregul>ities 9 ! =m ( ,saturn1 & ! great compression ( ,m>s1 prove ! int]nal /ructure ( ^! two planets to be v f> f uni=m4 ,be=e ent]+ on ! !ory ( rotation1 x may n be =eign to ! subject to give "s idea ( ! me?ods ( comput+ ! places ( ! planets1 & ( =m+ a/ronomical tables4 ,a/ronomy is n[ divid$ into ! ?ree di/9ct dep>tm5ts ( !ory1 obs]vation1 & computation4 ,s9ce ! problem ( ! ?ree bodies c only be solv$ by approximation1 ! analytical a/ronom] det]m9es ! position ( a planet 9 space by a s]ies ( corrections4 ,its place 9 its circul> orbit is fir/ f\nd1 !n ! addition or subtraction ( ! equation ( ! c5tre 7,n4 #dh7 to or f its mean place gives its position 9 ! ellipse4 ,?is aga9 is correct$ by ! application ( ! pr9cipal p]iodic inequalities4 ,b1 z ^! are det]m9$ = "s p>ticul> position ( ! ?ree bodies1 !y require to be correct$ to suit o!r relative positions4 ,?is process is cont9u$ till ! corrections become less ?an ! errors ( obs]vation1 :5 x is obvi\sly unnecess>y to c>ry ! approximation fur!r4 ,! true latitude & di/ance ( ! planet f ! sun are obta9$ by me?ods simil> to ^? employ$ = ! longitude4 ,z ! e>? revolves equably ab\t its axis 9 #bd h\rs1 at ! rate ( #ae 9 an h\r1 "t becomes a measure ( angul> motion1 & ! pr9cipal elem5t 9 a/ronomy1 :]e ! object is to det]m9e ! exact /ate ( ! heav5s & ! successive *anges x und]goes 9 all ages1 pa/1 pres5t1 & to come4 ,n[1 ! longitude1 latitude1 & di/ance ( a planet f ! sun are giv5 9 t]ms ( ! "t1 by g5]al analytical =mul4 ,^! =mul w consequ5tly give ! exact place ( ! body 9 ! heav5s1 = any "t assum$ at pleasure1 provid$ !y c be r$uc$ to numb]s4 ,b be=e ! calculator beg9s 8 task ! obs]v] mu/ furni% ! necess>y data1 :i* are1 obvi\sly1 ! =ms ( ! orbits1 & _! positions ) reg>d to ! plane ( ! ecliptic 7,n4 #eg74 ,x is !re=e necess>y to det]m9e by obs]vation1 = ea* planet1 ! l5g? ( ! major axis ( its orbit1 ! exc5tricity1 ! incl9ation ( ! orbit to ! plane ( ! ecliptic1 ! longitudes ( its p]ihelion & asc5d+ node at a giv5 "t1 ! p]iodic "t ( ! planet1 & its longitude at any in/ant arbitr>ily assum$1 z an orig9 f :5ce all its subsequ5t & antec$5t longitudes are e/imat$4 ,ea* ( ^! quantities is det]m9$ f t position ( ! planet on :i* x has mo/ influ5ce4 ,= example1 ! sum ( ! greate/ & lea/ di/ances ( ! planet f ! sun is equal to ! major axis ( ! orbit1 & _! diff]5ce is equal to twice ! exc5tricity4 ,! longitude ( ! planet1 :5 at its lea/ di/ance f ! sun1 is ! same ) ! longitude ( ! p]ihelion2 ! greate/ latitude ( ! planet is equal to ! incl9ation ( ! orbit3 ! longitude ( ! planet1 :5 9 ! plane ( ! ecliptic 9 pass+ t[>ds ! nor?1 is ! longitude ( ! asc5d+ node1 & ! p]iodic "t is ! int]val betwe5 two consecutive passages ( ! planet ?r\gh ! same node1 a small correction be+ made = ! precession ( ! node dur+ ! revolution ( ! planet 7,n4 #acg74 ,not)/&+ ! excell5ce ( in/rum5ts & ! accuracy ( mod]n obs]v]s1 unavoidable errors ( obs]vation c only be comp5sat$ by f9d+ ! value ( ea* elem5t f ! mean ( a ?\s&1 or ev5 _m ?\s&s ( obs]vations4 ,= z x is probable t ! errors are n all 9 "o direction1 b t "s are 9 excess & o!rs 9 defect1 !y w comp5sate ea* o!r :5 comb9$4 ,h[ev]1 ! values ( ! elem5ts det]m9$ sep>ately c only be reg>d$ z approximate1 because !y are s connect$ t ! e/imation ( any "o indep5d5tly w induce errors 9 ! o!rs4 ,! exc5tricity dep5ds ^u ! longitude ( ! p]ihelion1 ! mean motion dep5ds ^u ! major axis1 ! longitude ( ! node ^u ! incl9ation ( ! orbit1 & vice v]s4 ,consequ5tly1 ! place ( a planet comput$ ) ! approximate data w diff] f its obs]v$ place4 ,!n ! difficulty is to asc]ta9 :at elem5ts are mo/ 9 fault1 s9ce ! diff]5ce 9 "q is ! error ( all2 t is obviat$ by f9d+ ! errors ( "s ?\s&s ( obs]vations1 & comb9+ !m1 s z to correct ! elem5ts simultane\sly1 & to make ! sum ( ! squ>es ( ! errors a m9imum ) reg>d to ea* elem5t 7,n4 #ach74 ,! me?od ( accompli%+ ?is dep5ds ^u ! ,!ory ( ,probabilities2 a subject f]tile 9 mo/ important results 9 ! v>i\s dep>tm5ts ( sci5ce & ( civil life1 & q indisp5sable 9 ! det]m9ation ( a/ronomical data4 ,a s]ies ( obs]vations cont9u$ = "s ye>s w give approximate values ( ! secul> & p]iodic inequalities1 :i* mu/ be correct$ f "t to "t1 till !ory & obs]vation agree4 ,& ^! aga9 w give values ( ! masses ( ! bodies =m+ ! sol> sy/em1 :i* are important data 9 comput+ _! motions4 ,! p]iodic inequalities d]iv$ f a great numb] ( obs]vations are employ$ = ! det]m9ation ( ! values ( ! masses till su* "t z ! secul> inequalities %all be p]fectly kn[n1 :i* w !n give !m ) all ! necess>y precision4 ,:5 all ^! quantities are det]m9$ 9 numb]s1 ! longitude1 latitude1 & di/ance ( ! planet f ! sun are comput$ = /at$ int]vals1 & =m$ into tables1 arrang$ accord+ to ! "t e/imat$ f a giv5 epo*1 s t ! place ( ! body may be det]m9$ f !m by inspection alone1 at any in/ant = p]haps a ?\s& ye>s be=e & aft] t epo*4 ,by ?is t$i\s process1 tables h be5 comput$ = all ! great planets1 & sev]al ( ! small1 besides ! moon & ! satellites ( ,jupit]4 ,9 ! pres5t /ate ( a/ronomy ! masses & elem5ts ( ! orbits are pretty well kn[n1 s t ! tables only require to be correct$ f "t to "t z obs]vations become m accurate4 ,^? conta9+ ! motions ( ,jupit]1 ,saturn1 & ,uranus h already be5 twice con/ruct$ )9 ! la/ ?irty ye>s1 & ! tables ( ,jupit] & ,saturn agree almo/ p]fectly ) mod]n obs]vation4 ,! foll[+ pr$iction w be f\nd 9 ! six? edition ( ?is book1 publi%$ 9 ! ye> #ahdb3 8,^? ( ,uranus1 h[ev]1 are already defective1 probably because ! discov]y ( t planet 9 #agha is too rec5t to admit ( mu* precision 9 ! det]m9ation ( its motions1 or t possibly x may be subject to di/urbances f "s unse5 planet revolv+ ab\t ! sun beyond ! pres5t b\nd>ies ( our sy/em4 ,if1 aft] a lapse ( ye>s1 ! tables =m$ f a comb9ation ( num]\s obs]vations %\ld be /ill inadequate to repres5t ! motions ( ,uranus1 ! discrepancies may reveal ! exi/5ce1 nay1 ev5 ! mass & orbit1 ( a body plac$ = ev] beyond ! sph]e ( vision40#e ,t pr$iction has be5 fulfill$ s9ce ! sev5? edition ( ?is book 0 publi%$4 ,n only ! exi/5ce ( ,neptune1 revolv+ at ! di/ance ( ?ree ?\s& millions ( miles f ! sun1 has be5 discov]$ f 8 di/urb+ action on ,uranus1 b 8 mass1 ! =m & position ( 8 orbit 9 space1 & 8 p]iodic "t _h be5 det]m9$ be=e ! planet _h be5 se51 & ! planet itself 0 discov]$ 9 ! v po9t ( ! heav5s :i* _h be5 assign$ to x4 ,x _h be5 notic$ = ye>s t ! p]turbation ( ,uranus _h increas$ 9 an unacc\ntable mann] 7,n4 #aci74 ,aft] ! di/urb+ action ( all ! kn[n planets _h be5 det]m9$1 x 0 f\nd t1 betwe5 ! ye>s #ahcc & #ahcg1 ! obs]v$ & comput$ di/ance ( ,uranus f ! sun diff]$ by #bdj1jjj miles1 :i* is ab\t ! mean di/ance ( ! moon f ! e>?1 :ile1 9 #ahda1 ! error 9 ! geoc5tric longitude ( ! planet am\nt$ to #if4 ,^! discrepancies 7 !re=e attribut$ to ! attraction ( "s unse5 & unkn[n planet1 consequ5tly !y gave rise to a case altoge!r unprec$5t$ 9 ! hi/ory ( a/ronomy4 ,h]et(ore x 0 requir$ to det]m9e ! di/urb+ action ( "o kn[n planet ^u ano!r4 ,:]eas ! inv]se problem _h n[ to be solv$1 9 :i* x 0 requir$ to f9d ! place ( an unkn[n body 9 ! heav5s1 at a giv5 "t1 toge!r ) its mass1 & ! =m & position ( its orbit1 f ! di/urbance x produc$ on ! motions ( ano!r4 ,! difficulty 0 extreme1 because all ! elem5ts ( ! orbit ( ,uranus 7 errone\s f ! action ( ,neptune1 & ^? ( ,neptune's orbit 7 unkn[n4 ,9 ?is dilemma x 0 necess>y to =m "s hypo!sis ) reg>d to ! unkn[n planet2 x 0 !re=e assum$1 accord+ to ,bode's empirical law on ! mean di/ances ( ! planets1 t x 0 revolv+ at twice ! di/ance ( ,uranus f ! sun4 ,9 fact1 ! p]iodic "t ( ,uranus is ab\t #hd ye>s1 &1 z ! discrepancies 9 8 motions increas$ sl[ly & regul>ly1 x 0 evid5t t x w\ld require a planet ) a mu* long] p]iodic "t to produce !m--moreov]1 x 0 cle> t ! new planet mu/ be ext]ior to ,uranus1 o!rwise x w\ld h di/urb$ ! motions ( ,saturn4 ,ano!r circum/ance t5d$ to less5 ! difficulty2 ! latitude ( ,uranus 0 n mu* affect$1 !re=e x 0 conclud$ t ! incl9ation ( ! orbit ( ! unkn[n body mu/ be v small1 &1 z t ( ! orbit ( ,uranus is only #df #bhd1 bo? planets 7 assum$ to be mov+ 9 ! plane ( ! ecliptic1 & ?us ! elem5ts ( ! orbit ( ! unkn[n planet 7 r$uc$ f six to f\r4 ,hav+ ?us assum$ t ! unkn[n body 0 revolv+ 9 a circle 9 ! plane ( ! ecliptic1 ! analytical expression ( its action on ! motion ( ,uranus1 :5 9 num]\s po9ts ( its orbit1 0 comp>$ ) ! obs]v$ longitude ( ,uranus1 ?r\gh a regul> s]ies ( ye>s1 by means ( :i* ! faulty elem5ts ( ! orbit ( ,uranus 7 elim9at$1 or got rid (1 & !re only rema9$ a relation betwe5 ! mass ( ! new planet & ?ree ( ! elem5ts ( its orbit2 & x !n 0 necess>y to assume su* a value = two ( !m z w\ld suit ! re/4 ,t 0 accompli%$ s dext]\sly1 t ! p]turbations ( ,uranus 7 p]fectly con=mable to ! motions ( ,neptune1 mov+ 9 ! orbit ?us f\nd1 & ! place ( ! new planet exactly agre$ ) obs]vation4 ,subsequ5tly its orbit & motions h be5 det]m9$ m accurately4 ,! hon\r ( ?is admirable ef=t ( g5ius is %>$ by ,mr4 ,adams & ,m4 ,le ,v]ri]1 :o1 indep5d5tly ( ea* o!r1 arriv$ at ^! wond]ful results4 ,mr4 ,adams _h det]m9$ ! mass & app>5t diamet] ( ,neptune1 ) all ! circum/ances ( its motion1 eight mon?s be=e ,m4 ,le ,v]ri] _h t]m9at$ 8 results1 & _h also po9t$ out ! exact spot :]e ! planet w\ld be f\nd2 b ! ,engli% obs]v]s neglect$ to look = x till ,m4 ,le ,v]ri] made kn[n 8 rese>*es1 & communicat$ its position to ,dr4 ,galle1 at ,b]l91 :o f\nd x ! v fir/ night he look$ = x1 & !n x 0 evid5t t x w\ld h be5 se5 9 ! place ,mr4 ,adams _h assign$ to x eight mon?s be=e _h x be5 look$ =4 ,s closely did ! results ( ^! two great ma!maticians agree4 ,neptune has a diamet] ( #ci1gic miles1 consequ5tly he is ne>ly #bjj times l>g] ?an ! e>?1 & may be se5 ) a telescope ( mod]ate p[]4 ,8 motion is retrograde at pres5t1 & six times sl[] ?an t ( ! e>?4 ,at s great a di/ance f ! sun x c only h ! #a_/acjj? "p ( ! light & heat ! e>? receives2 b hav+ a satellite1 ! defici5cy ( light may 9 "s measure be suppli$4 ,! pr$iction may n[ be transf]r$ f ,uranus to ,neptune1 ^: p]turbations may reveal ! exi/5ce ( a planet /ill fur!r remov$1 :i* may = ev] rema9 beyond ! rea* ( telescopic vision--yet its mass1 ! =m & position ( its orbit1 & all ! circum/ances ( its motion may become kn[n1 & ! limits ( ! sol> sy/em may /ill be ext5d$ hundr$s ( millions ( miles4 ,! mean di/ance ( ,neptune f ! sun has subsequ5tly prov$ to be only #bhic millions ( miles1 & ! p]iod ( 8 revolution #aff ye>s1 s t ,b>on ,bode's law1 ( ! int]val betwe5 ! orbits ( any two planets be+ twice z great z ! inf]ior int]val & half ( ! sup]ior1 fails 9 ! case ( ,neptune1 ?\gh x 0 useful on ! fir/ approximation to 8 motions2 & s9ce ,bode's "t x has l$ to ! discov]y ( fifty-five telescopic planets revolv+ betwe5 ! orbits ( ,m>s & ,jupit]1 "s by *ance1 o!rs by a sy/ematic se>* on ! fai? t ^! m9ute planets are fragm5ts ( a l>g] body t has explod$1 because _! di/ances f ! sun are ne>ly ! same2 ! l9es ( ! nodes ( "s ( _! orbits t]m9ate 9 ! same po9ts ( ! heav5s1 & ! incl9ations ( _! orbits are su* z might h tak5 place f _! mutual di/urbances at ! "t ( ! explosion1 & :ile yet !y 7 ne> en\gh = _! =ms to affect _! motions4 ,! orbits ( ! m rec5tly discov]$ a/]oids %[ t ?is hypo!sis is unt5able4 ,! tables ( ,m>s1 ,v5us1 & ev5 ^? ( ! sun1 h be5 greatly improv$1 & /ill engage ! att5tion ( our ,a/ronom] ,royal1 ,mr4 ,airy1 & o!r em95t a/ronom]s4 ,we are *iefly indebt$ to ! ,g]man a/ronom]s = tables ( ! f\r old] telescopic planets1 ,ve/a1 ,juno1 ,c]es1 & ,pallas2 ! o!rs h only be5 discov]$ s9ce ! ye> #ahde4 ,! det]m9ation ( ! pa? ( a planet :5 di/urb$ by all ! o!rs1 a problem :i* has employ$ ! tal5ts ( ! greate/ a/ronom]s1 f ,newton to ! pres5t day1 is only successfully accompli%$ ) reg>d to ! old] planets1 :i* revolve 9 ne>ly circul> orbits1 b little incl9$ to ! plane ( ! ecliptic4 ,:5 ! exc5tricity & incl9ation ( ! orbits are great1 _! analysis fails1 because ! s]ies express+ ! co-ord9ates ( ! bodies become extremely complicat$1 & d n conv]ge :5 appli$ to comets & ! telescopic planets4 ,?is difficulty has be5 ov]come by ,sir ,john ,lubbock1 & o!r ma!maticians1 :o h ! hon\r ( hav+ complet$ ! !ory ( planet>y motion1 :i* becomes e day ( m importance1 f ! new planets t h be5 discov]$1 & also ) reg>d to comets1 _m ( :i* return to ! sun at regul> int]vals1 & f ^: p]turbations ! masses ( ! planets w be m accurately det]m9$1 & ! ret>d+ influ5ce ( ! e!real m$ium bett] kn[n4 ,,section ,,ix4 ,rotation ( ! ,sun & ,planets--,saturn's ,r+s--,p]iods ( ! ,rotation ( ! ,moon & o!r ,satellites equal to ! ,p]iods ( _! ,revolutions--,=m ( ,lun> ,sph]oid--,libration1 ,aspect1 & ,con/itution ( ! ,moon--,rotation ( ,jupit]'s ,satellites4 ,,! oblate =m ( sev]al ( ! planets indicates rotatory motion4 ,?is has be5 confirm$ 9 mo/ cases by trac+ spots on _! surface1 by :i* _! poles & times ( rotation h be5 det]m9$4 ,! rotation ( ,m]cury is unkn[n1 on acc\nt ( 8 proximity to ! sun2 t ( ! new planets has n yet be5 asc]ta9$4 ,! sun revolves 9 tw5ty-five days & t5 h\rs ab\t an axis :i* is direct$ t[>ds a po9t half-way betwe5 ! pole-/> & ( ,lyra1 ! plane ( rotation be+ incl9$ by #g #cj1 or a little m ?an sev5 degrees1 to ! plane ( ! ecliptic3 x may !re=e be conclud$ t ! sun's mass is a sph]oid1 flatt5$ at ! poles4 ,f ! rotation ( ! sun1 !re 0 e reason to believe t he has a progressive motion 9 space1 a circum/ance :i* is confirm$ by obs]vation4 ,b1 9 consequ5ce ( ! reaction ( ! planets1 he describes a small irregul> orbit ab\t ! c5tre ( gravity ( ! sy/em1 nev] deviat+ f 8 position by m ?an twice 8 own diamet]1 or a little m ?an sev5 times ! di/ance ( ! moon f ! e>?4 ,! sun & all 8 att5dants rotate f we/ to ea/1 on axes t rema9 ne>ly p>allel to !mselves 7,n4 #adj7 9 e po9t ( _! orbit1 & ) angul> velocities t are s5sibly uni=m 7,n4 #ada74 ,al?\gh ! uni=mity 9 ! direction ( _! rotation is a circum/ance hi!rto unacc\nt$ = 9 ! economy ( nature1 yet1 f ! design & adaptation ( e o!r "p to ! p]fection ( ! :ole1 a co9cid5ce s rem>kable _c be accid5tal4 ,&1 z ! revolutions ( ! planets & satellites are also f we/ to ea/1 x is evid5t t bo? mu/ h aris5 f ! primitive cause :i* det]m9$ ! planet>y motions4#f ,inde$1 ,la ,place has comput$ ! probability to be z f\r millions to "o t all ! motions ( ! planets1 bo? ( rotation & revolution1 7 at once imp>t$ by an orig9al common cause1 b ( :i* we "k nei!r ! nature nor ! epo*4 ,! l>g] planets rotate 9 %ort] p]iods ?an ! small] planets & ! e>?4 ,_! compression is consequ5tly great]1 & ! action ( ! sun & ( _! satellites occasions a nutation 9 _! axes & a precession ( _! equ9oxes 7,n4 #adg7 simil> to t :i* obta9s 9 ! t]re/rial sph]oid1 f ! attraction ( ! sun & moon on ! prom95t matt] at ! equator4 ,jupit] revolves 9 less ?an t5 h\rs r\nd an axis at "r angles to c]ta9 d>k belts or b&s1 :i* always cross 8 equator4 7,see ,plate #a47 ,?is rapid rotation occasions a v great compression 9 8 =m4 ,8 equatorial axis exce$s 8 pol> axis by #fjjj miles1 :]eas ! diff]5ce 9 ! axes ( ! e>? is only ab\t tw5ty-six & a half4 ,x is an evid5t consequ5ce ( ,kepl]'s law ( ! squ>es ( ! p]iodic times ( ! planets be+ z ! cubes ( ! major axes ( _! orbits1 t ! heav5ly bodies move sl[] ! f>!r !y are f ! sun4 ,9 comp>+ ! p]iods ( ! revolutions ( ,jupit] & ,saturn ) ! times ( _! rotation1 x appe>s t a ye> ( ,jupit] conta9s ne>ly t5 ?\s& ( 8 days1 & t ( ,saturn ab\t ?irty ?\s& ,saturnian days4 ,! appe>ance ( ,saturn is unp>allel$ 9 ! sy/em ( ! _w4 ,he is a sph]oid ne>ly #ajjj times l>g] ?an ! e>?1 surr\nd$ by a r+ ev5 bright] ?an himself1 :i* always rema9s susp5d$ 9 ! plane ( 8 equator3 &1 view$ ) a v good telescope1 x is f\nd to consi/ ( two conc5tric r+s1 divid$ by a d>k b&4 ,! ext]ior r+1 z se5 ?r\gh ,mr4 ,lassell's great equatorial at ,malta1 has a d>k-/rip$ b& ?r\gh ! c5tre1 & is altoge!r less bright ?an ! int]ior r+1 "o half ( :i* is extremely brilliant2 :ile ! int]ior half is %ad$ 9 r+s l ! seats 9 an amphi!atre4 ,mr4 ,lassell made ! rem>kable discov]y ( a d>k transp>5t r+1 ^: edge co9cides ) ! inn] edge ( ! int]ior r+1 & :i* occupies ab\t half ! space betwe5 x & ,saturn4 ,he comp>es x to a b& ( d>k-col\r$ crape drawn across a portion ( ! disc ( ! planet1 & ! "p project$ ^u ! blue sky is also transp>5t4 ,at ! "t ^! obs]vations 7 made at ,malta1 ,capta9 ,jacob discov]$ ! transp>5t r+ at ,madras4 ,x is conjectur$ to be fluid2 ev5 ! lum9\s r+s _c be v d5se1 s9ce ! d5sity ( ,saturn himself is kn[n to be less ?an ! eigh? "p ( t ( ! e>?4 ,a transit ( ! r+ across a /> might reveal some?+ conc]n+ ?is wond]ful object4 ,! ball ( ,saturn is /rip$ by belts ( diff]5t col\rs4 ,at ! "t ( ^! obs]vations ! "p above ! r+ 0 bright :ite2 at 8 equator !re 0 a ruddy belt divid$ 9 two1 above :i* 7 belts ( a blui% gre5 alt]nately d>k & light1 :ile at ! pole !re 0 a circul> space ( a pale col\r4 7,see ,plate #b47 ,! mean di/ance ( ! int]ior "p ( ! d\ble r+ f ! surface ( ! planet is ab\t #bb1bdj miles1 x is no less ?an #cc1cfj miles broad1 b1 by ! e/imation ( ,sir ,john ,h]s*el1 its ?ickness does n mu* exce$ #ajj miles1 s t x appe>s l a plane4 ,by ! laws ( me*anics1 x is impossible t ?is body c reta9 its position by ! adhesion ( its p>ticles alone4 ,x mu/ necess>ily revolve ) a velocity t w g5]ate a c5trifugal =ce suffici5t to balance ! attraction ( ,saturn4 ,obs]vation confirms ! tru? ( ^! pr9ciples1 %[+ t ! r+s rotate f we/ to ea/ ab\t ! planet 9 t5 h\rs & a half1 :i* is ne>ly ! "t a satellite w\ld take to revolve ab\t ,saturn at ! same di/ance4 ,_! plane is incl9$ to ! ecliptic1 at an angle ( #bh #aj #dde2 9 consequ5ce ( ?is obliquity ( position1 !y always appe> elliptical to u1 b ) an exc5tricity s v>iable z ev5 to be occasionally l a /raight l9e drawn across ! planet4 ,9 ! beg9n+ ( ,octob]1 #ahcb1 ! plane ( ! r+s pass$ ?r\gh ! c5tre ( ! e>?2 9 t position !y are only visible ) v sup]ior in/rum5ts1 & appe> l a f9e l9e across ! disc ( ,saturn4 ,ab\t ! middle ( ,decemb]1 9 ! same ye>1 ! r+s became invisible1 ) ord9>y in/rum5ts1 on acc\nt ( _! plane pass+ ?r\gh ! sun4 ,9 ! end ( ,april1 #ahcc1 ! r+s vani%$ a second "t1 & reappe>$ 9 ,june ( t ye>4 ,simil> ph5om5a w occur z (t5 z ,saturn has ! same longitude ) ei!r node ( 8 r+s4 ,ea* side ( ^! r+s has alt]nately fifte5 ye>s ( sun%9e & fifte5 ye>s ( d>kness4 ,x is a s+ul> result ( !ory1 t ! r+s c\ld n ma9ta9 _! /ability ( rotation if !y 7 ev]y:]e ( uni=m ?ickness2 = ! smalle/ di/urbance w\ld de/roy ! equilibrium1 :i* w\ld become m & m d]ang$1 till1 at la/1 !y w\ld be precipitat$ on ! surface ( ! planet4 ,! r+s ( ,saturn mu/ !re=e be irregul> solids1 ( unequal bread? 9 diff]5t p>ts ( ! circumf]5ce1 s t _! c5tres ( gravity d n co9cide ) ! c5tres ( _! figures4 ,pr(essor ,/ruve has also discov]$ t ! c5tre ( ! r+s is n conc5tric ) ! c5tre ( ,saturn4 ,! int]val betwe5 ! out] edge ( ! globe ( ! planet & ! out] edge ( ! r+s on "o side is #aabgb1 &1 on ! o!r side1 ! int]val is #aacij1 consequ5tly !re is an exc5tricity ( ! globe 9 ! r+s ( #jbae4 ,if ! r+s obey$ diff]5t =ces1 !y w\ld n rema9 9 ! same plane1 b ! p[]ful attraction ( ,saturn always ma9ta9s !m & 8 satellites 9 ! plane ( 8 equator4 ,! r+s1 by _! mutual action1 & t ( ! sun & satellites1 mu/ oscillate ab\t ! c5tre ( ,saturn1 & produce ph5om5a ( light & %ad[ ^: p]iods ext5d to _m ye>s4 ,accord+ to ,m4 ,bessel ! mass ( ,saturn's r+ is equal to ! #a_/aah "p ( t ( ! planet4 ,! p]iods ( rotation ( ! moon & ! o!r satellites are equal to ! times ( _! revolutions1 consequ5tly ^! bodies always turn ! same face to _! prim>ies4 ,h[ev]1 z ! mean motion ( ! moon is subject to a secul> inequality1 :i* w ultimately am\nt to _m circumf]5ces 7,n4 #ajh71 if ! rotation ( ! moon 7 p]fectly uni=m & n affect$ by ! same inequalities1 x w\ld cease exactly to c\nt]balance ! motion ( revolution2 & ! moon1 9 ! c\rse ( ages1 w\ld successively & gradually discov] e po9t ( h] surface to ! e>?4 ,b !ory proves t ?is nev] c happ52 = ! rotation ( ! moon1 ?\gh x does n p>take ( ! p]iodic inequalities ( h] revolution1 is affect$ by ! same secul> v>iations1 s t h] motions ( rotation & revolution r\nd ! e>? w always balance ea* o!r1 & rema9 equal4 ,?is circum/ance arises f ! =m ( ! lun> sph]oid1 :i* has ?ree pr9cipal axes ( diff]5t l5g?s at "r angles to ea* o!r4 ,! moon is flatt5$ at h] poles f h] c5trifugal =ce1 !re=e h] pol> axis is ! lea/4 ,! o!r two are 9 ! plane ( h] equator1 b t direct$ t[>ds ! e>? is ! greate/ 7,n4 #adb74 ,! attraction ( ! e>?1 z if x _h drawn out t "p ( ! moon's equator1 con/antly br+s ! greate/ axis1 & consequ5tly ! same hemisph]e1 t[>ds u1 :i* makes h] rotation p>ticipate 9 ! secul> v>iations ( h] mean motion ( revolution4 ,ev5 if ! angul> velocities ( rotation & revolution _h n be5 nicely balanc$ 9 ! beg9n+ ( ! moon's motion1 ! attraction ( ! e>? w\ld h recall$ ! greate/ axis to ! direction ( ! l9e jo9+ ! c5tres ( ! moon & e>?2 s t x w\ld h vibrat$ on ea* side ( t l9e 9 ! same mann] z a p5dulum oscillates on ea* side ( ! v]tical f ! influ5ce ( gravitation4 ,no su* libration is p]ceptible2 &1 z ! smalle/ di/urbance w\ld make x evid5t1 x is cle> t1 if ! moon has ev] be5 t\*$ by a comet1 ! mass ( ! latt] mu/ h be5 extremely small4 ,if x _h be5 only ! hundr$ ?\s&? "p ( t ( ! e>?1 x w\ld h r5d]$ ! libration s5sible4 ,accord+ to analysis1 a simil> libration exi/s 9 ! motions ( ,jupit]'s satellites1 :i* /ill rema9s ins5sible to obs]vation1 & yet ! comet ( #aggj pass$ twice ?r\gh ! mid/ ( !m4 ,! moon1 x is true1 is liable to librations dep5d+ ^u ! position ( ! spectator4 ,at h] ris+1 "p ( ! we/]n edge ( h] disc is visible1 :i* is invisible at h] sett+1 & ! contr>y takes place ) reg>d to h] ea/]n edge4 ,!re are also librations aris+ f ! relative positions ( ! e>? & moon 9 _! respective orbits2 b1 z !y are only optical appe>ances1 "o hemisph]e w be et]nally conceal$ f ! e>?4 ,= ! same reason ! e>?1 :i* mu/ be s spl5did an object to "o lun> hemisph]e1 w be = ev] veil$ f ! o!r4 ,on acc\nt ( ^! circum/ances1 ! remot] hemisph]e ( ! moon has its day a =tnight long1 & a night ( ! same duration1 n ev5 enlight5$ by a moon1 :ile ! fav\r$ side is illum9at$ by ! reflection ( ! e>? dur+ its long night4 ,a planet exhibit+ a surface ?irte5 times l>g] ?an t ( ! moon1 ) all ! v>ieties ( cl\ds1 l&1 & wat]1 com+ successively into view1 mu/ be a spl5did object to a lun> travell] 9 a j\rney to 8 antipodes4 ,! great height ( ! lun> m\nta9s probably has a consid]able influ5ce on ! ph5om5a ( h] motion1 ! m s z h] compression is small1 & h] mass consid]able4 ,9 ! curve pass+ ?r\gh ! poles1 & t diamet] ( ! moon :i* always po9ts to ! e>?1 nature has furni%$ a p]man5t m]idian1 to :i* ! diff]5t spots on h] surface h be5 ref]r$1 & _! positions are det]m9$ ) z mu* accuracy z ^? ( _m ( ! mo/ rem>kable places on ! surface ( our globe4 ,accord+ to ! obs]vations ( ,pr(essor ,sec*i at ,rome1 ! m\nta9s ( ! moon are mo/ly volcanic & ( ?ree k9ds4 ,! fir/ & olde/ h _! bord]s oblit]at$1 s t !y look l deep wells2 ! second1 :i* are ( an int]m$iate class1 h elevat$1 &1 = ! mo/ "p1 regul> unbrok5 edges1 ) ! gr\nd ar\nd !m rais$ to a prodigi\s ext5t 9 proportion to ! size ( ! volcano1 ) g5]ally an insulat$ rock 9 ! c5tre ( ! crat]4 ,! ?ird1 & mo/ rec5t class1 are v small1 & seem to be ! la/ ef=t ( ! expir+ volcanic =ce1 :i* is probably n[ ext9ct4 ,! di/ance & m9ut5ess ( ,jupit]'s satellites r5d] x extremely difficult to asc]ta9 _! rotation4 ,x 01 h[ev]1 accompli%$ by ,sir ,william ,h]s*el f _! relative brightness4 ,he obs]v$ t !y alt]nately exce$ ea* o!r 9 brilliancy1 &1 by comp>+ ! maxima & m9ima ( _! illum9ation ) _! positions relatively to ! sun & to _! prim>y1 he f\nd t1 l ! moon1 ! "t ( _! rotation is equal to ! p]iod ( _! revolution ab\t ,jupit]4 ,miraldi 0 l$ to ! same conclusion ) reg>d to ! f\r? satellite1 f ! motion ( a spot on its surface4 ,,section ,x4 ,rotation ( ! ,e>? inv>iable--,decrease 9 ! ,e>?'s mean ,temp]ature--,e>? orig9ally 9 a /ate ( ,fusion--,l5g? ( ,day con/ant--,decrease ( ,temp]ature ascrib$ by ,sir ,john ,h]s*el to ! v>iation 9 ! ,exc5tricity ( ! ,t]re/rial ,orbit--,diff]5ce 9 ! ,temp]ature ( ! two ,hemisph]es errone\sly ascrib$ to ! ,excess 9 ! ,l5g? ( ,spr+ & ,summ] 9 ! ,s\!rn ,hemisph]e2 attribut$ by ,sir ,*>les ,lyell to ! ,op]ation ( exi/+ ,causes--,?ree pr9cipal ,axes ( ,rotation--,position ( ! ,axis ( ,rotation on ! ,surface ( ! ,e>? inv>iable--,ocean n suffici5t to re/ore ! ,equilibrium ( ! ,e>? if d]ang$--,its ,d5sity & mean ,dep?--,int]nal ,/ructure ( ! ,e>?4 ,! rotation ( ! e>?1 :i* det]m9es ! l5g? ( ! day1 may be reg>d$ z "o ( ! mo/ important elem5ts 9 ! sy/em ( ! _w4 ,x s]ves z a measure ( "t1 & =ms ! /&>d ( comp>ison = ! revolutions ( ! cele/ial bodies1 :i*1 by _! proportional increase or decrease1 w\ld soon disclose any *anges x might su/a94 ,!ory & obs]vation concur 9 prov+ t1 among ! innum]able vicissitudes :i* prevail ?r\gh\t creation1 ! p]iod ( ! e>?'s diurnal rotation is immutable4 ,! wat] ( riv]s1 fall+ f a high] to a l[] level1 c>ries ) x ! velocity due to its revolution ) ! e>? at a great] di/ance f ! c5tre2 x w !re=e accel]ate1 al?\gh to an almo/ inf9itesimal ext5t1 ! e>?'s daily rotation4 ,! sum ( all ^! increm5ts ( velocity1 aris+ f ! desc5t ( all ! riv]s on ! e>?'s surface1 w\ld 9 "t become p]ceptible1 did n nature1 by ! process ( evaporation1 raise ! wat]s back to _! s\rces1 & ?us1 by aga9 remov+ matt] to a great] di/ance f ! c5tre1 de/roy ! velocity g5]at$ by its previ\s approa*2 s t ! desc5t ( riv]s does n affect ! e>?'s rotation4 ,enorm\s masses project$ by volcanoes f ! equator to ! poles1 & ! contr>y1 w\ld inde$ affect x1 b !re is no evid5ce ( su* convulsions4 ,! di/urb+ action ( ! moon & planets1 :i* has s p[]ful an effect on ! revolution ( ! e>?1 9 no way influ5ces its rotation4 ,! con/ant friction ( ! trade w9ds on ! m\nta9s & cont95ts betwe5 ! tropics does n imp$e its velocity1 :i* !ory ev5 proves to be ! same z if ! sea1 toge!r ) ! e>?1 =m$ "o solid mass4 ,b1 al?\gh ^! circum/ances be insuffici5t1 a v>iation 9 ! mean temp]ature w\ld c]ta9ly occasion a correspond+ *ange 9 ! velocity ( rotation4 ,9 ! sci5ce ( dynamics x is a pr9ciple 9 a sy/em ( bodies or ( p>ticles revolv+ ab\t a fix$ c5tre1 t ! mom5tum or sum ( ! products ( ! mass ( ea* into its angul> velocity & di/ance f ! c5tre is a con/ant quantity1 if ! sy/em be n d]ang$ by a =eign cause4 ,n[1 s9ce ! numb] ( p>ticles 9 ! sy/em is ! same :atev] its temp]ature may be1 :5 _! di/ances f ! c5tre are dim9i%$1 _! angul> velocity mu/ be increas$1 9 ord] t ! prec$+ quantity may /ill rema9 con/ant4 ,x foll[s1 !n1 t1 z ! primitive mom5tum ( rotation ) :i* ! e>? 0 project$ into space mu/ necess>ily rema9 ! same1 ! smalle/ decrease 9 heat1 by contract+ ! t]re/rial sph]oid1 w\ld accel]ate its rotation1 & consequ5tly dim9i% ! l5g? ( ! day4 ,not)/&+ ! con/ant accession ( heat f ! sun's rays1 geologi/s h be5 induc$ to believe1 f ! fossil rema9s1 t ! mean temp]ature ( ! globe is decreas+4 ,! high temp]ature ( m9es1 hot spr+s1 & above all ! int]nal fires :i* h produc$1 & d /ill occasion1 su* deva/ation on our planet1 indicate an augm5tation ( heat t[>ds its c5tre4 ,! increase ( d5sity correspond+ to ! dep? & ! =m ( ! sph]oid1 be+ :at !ory assigns to a fluid mass 9 rotation1 concurs to induce ! idea t ! temp]ature ( ! e>? 0 orig9ally s high z to r$uce all ! sub/ances ( :i* x is compos$ to a /ate ( fusion or ( vap\r1 & t 9 ! c\rse ( ages x has cool$ d[n to its pres5t /ate2 t x is /ill becom+ cold]2 & t x w cont9ue to d s till ! :ole mass arrives at ! temp]ature ( ! m$ium 9 :i* x is plac$1 or r at a /ate ( equilibrium betwe5 ?is temp]ature1 ! cool+ p[] ( its own radiation1 & ! heat+ effect ( ! sun's rays4 ,previ\s to ! =mation ( ice at ! poles1 ! anci5t l&s ( nor!rn latitudes might1 no d\bt1 h be5 capable ( produc+ ^? tropical plants pres]v$ 9 ! coal-measures1 if inde$ su* plants c\ld fl\ri% )\t ! int5se light ( a tropical sun4 ,b1 ev5 if ! decreas+ temp]ature ( ! e>? be suffici5t to produce ! obs]v$ effects1 x mu/ be extremely sl[ 9 its op]ation2 =1 9 consequ5ce ( ! rotation ( ! e>? be+ a measure ( ! p]iods ( ! cele/ial motions1 x has be5 prov$ t1 if ! l5g? ( ! day _h decreas$ by ! ?ree-?\s&? "p ( a second s9ce ! obs]vations ( ,hipp>*us two ?\s& ye>s ago1 x w\ld h dim9i%$ ! secul> equation ( ! moon by #ddd4 ,x is1 !re=e1 beyond a d\bt t ! mean temp]ature ( ! e>? _c h s5sibly v>i$ dur+ t "t4 ,if1 !n1 ! appe>ances exhibit$ by ! /rata are really ow+ to a decrease ( int]nal temp]ature1 x ei!r %[s ! imm5se p]iods requisite to produce geological *anges1 to :i* two ?\s& ye>s are z no?+1 or t ! mean temp]ature ( ! e>? _h arriv$ at a /ate ( equilibrium be=e ^! obs]vations4 ,h[ev] /rong ! indications ( ! primitive fluidity ( ! e>?1 z !re is no direct pro( ( x1 ! hypo!sis c only be reg>d$ z v probable4 ,b "o ( ! mo/ pr(\nd philosoph]s & elegant writ]s ( mod]n times has f\nd 9 ! secul> v>iation ( ! exc5tricity ( ! t]re/rial orbit an evid5t cause ( decreas+ temp]ature4 ,t accompli%$ au?or1 9 po9t+ out ! mutual dep5d5cies ( ph5om5a1 says1 8,x is evid5t t ! mean temp]ature ( ! :ole surface ( ! globe1 9 s f> z x is ma9ta9$ by ! action ( ! sun at a high] degree ?an x w\ld h 7 ! sun ext+ui%$1 mu/ dep5d on ! mean quantity ( ! sun's rays :i* x receives1 or--:i* comes to ! same ?+--on ! total quantity receiv$ 9 a giv5 inv>iable "t2 &1 ! l5g? ( ! ye> be+ un*angeable 9 all ! fluctuations ( ! planet>y sy/em1 x foll[s t ! total am\nt ( sol> radiation w det]m9e1 ct]is p>ibus1 ! g5]al climate ( ! e>?4 ,n[1 x is n difficult to %[ t ?is am\nt is inv]sely proportional to ! m9or axis ( ! ellipse describ$ by ! e>? ab\t ! sun 7,n4 #adc71 reg>d$ z sl[ly v>iable2 & t1 !re=e1 ! major axis rema9+1 z we "k x to be1 con/ant1 & ! orbit be+ actually 9 a /ate ( approa* to a circle1 & consequ5tly ! m9or axis be+ on ! increase1 ! mean annual am\nt ( sol> radiation receiv$ by ! :ole e>? mu/ be actually on ! decrease4 ,we h1 !re=e1 an evid5t real cause to acc\nt = ! ph5om5on40 ,! limits ( ! v>iation 9 ! exc5tricity ( ! e>?'s orbit are unkn[n4 ,b1 if its ellipticity has ev] be5 z great z t ( ! orbit ( ,m]cury or ,pallas1 ! mean temp]ature ( ! e>? mu/ h be5 s5sibly high] ?an x is at pres5t4 ,:e!r x 0 great en\gh to r5d] our nor!rn climates fit = ! production ( tropical plants1 & = ! resid5ce ( ! elephant & o!r animals n[ inhabitants ( ! torrid zone1 x is impossible to say4 ,( ! decrease 9 temp]ature ( ! nor!rn hemisph]e !re is abundant evid5ce 9 ! fossil plants discov]$ 9 v high latitudes1 :i* c\ld only h exi/$ 9 a tropical climate1 & :i* mu/ h gr[n ne> ! spot :]e !y are f\nd1 f ! delicacy ( _! /ructure & ! p]fect /ate ( _! pres]vation4 ,?is *ange ( temp]ature has be5 errone\sly ascrib$ to an excess 9 ! duration ( spr+ & summ] 9 ! nor!rn hemisph]e1 9 consequ5ce ( ! exc5tricity ( ! sol> ellipse4 ,! l5g? ( ! seasons v>ies ) ! position ( ! p]ihelion 7,n4 #fd7 ( ! e>?'s orbit = two reasons4 ,on acc\nt ( ! exc5tricity1 small z x is1 any l9e pass+ ?r\gh ! c5tre ( ! sun divides ! t]re/rial ellipse into two unequal p>ts1 & by ! laws ( elliptical motion ! e>? moves ?r\gh ^! two portions ) unequal velocities4 ,! p]ihelion always lies 9 ! small] portion1 & !re ! e>?'s motion is ! mo/ rapid4 ,9 ! pres5t position ( ! p]ihelion1 spr+ & summ] nor? ( ! equator exce$ by ab\t eight days ! duration ( ! same seasons s\? ( x4 ,& #aj1dib ye>s ago ! s\!rn hemisph]e enjoy$ ! advantage we n[ possess f ! secul> v>iation ( ! p]ihelion4 ,yet ,sir ,john ,h]s*el has %[n t by ?is alt]nation nei!r hemisph]e acquires any excess ( light or heat above ! o!r2 =1 al?\gh ! e>? is ne>] to ! sun :ile mov+ ?r\gh t "p ( its orbit 9 :i* ! p]ihelion lies ?an 9 ! o!r "p1 & consequ5tly receives a great] quantity ( light & heat1 yet z x moves fa/] x is expos$ to ! heat = a %ort] "t4 ,9 ! o!r "p ( ! orbit1 on ! contr>y1 ! e>?1 be+ f>!r f ! sun1 receives few] ( 8 rays2 b because its motion is sl[]1 x is expos$ to !m = a long] "t2 &1 z 9 bo? cases ! quantity ( heat & ! angul> velocity v>y exactly 9 ! same proportion1 a p]fect comp5sation takes place 7,n4 #add74 ,s t ! exc5tricity ( ! e>?'s orbit has little or no effect on ! temp]ature correspond+ to ! diff]5ce ( ! seasons4 ,sir ,*>les ,lyell1 9 8 excell5t works on ,geology1 ref]s ! increas$ cold ( ! nor!rn hemisph]e to ! op]ation ( exi/+ causes ) m probability ?an mo/ !ories t h be5 advanc$ 9 solution ( ?is difficult subject4 ,! l(tie/ m\nta9s w\ld be repres5t$ by a gra9 ( s& on a globe six feet 9 diamet]1 & ! dep? ( ! ocean by a scrat* on its surface4 ,consequ5tly ! gradual elevation ( a cont95t or *a9 ( m\nta9s above ! surface ( ! ocean1 or _! depression bel[ x1 is no v great ev5t comp>$ ) ! magnitude ( ! e>?1 & ! en]gy ( its subt]ranean fires1 if ! same p]iods ( "t be admitt$ 9 ! progress ( geological z 9 a/ronomical ph5om5a1 :i* ! successive & v>i\s races ( ext9ct be+s %[ to h be5 imm5se4 ,climate is always m int5se 9 ! int]ior ( cont95ts ?an 9 isl&s or sea-coa/s4 ,an increase ( l& )9 ! tropics w\ld !re=e augm5t ! g5]al heat1 & an increase 9 ! temp]ate & frigid zones w\ld r5d] ! cold m sev]e4 ,n[ x appe>s t mo/ ( ! ,european1 ,nor? ,asiatic1 & ,nor? ,am]ican cont95ts & isl&s 7 rais$ f ! deep aft] ! coal-measures 7 =m$ 9 :i* ! fossil tropical plants are f\nd2 & a v>iety ( geological facts indicate ! exi/5ce ( an anci5t & ext5sive ar*ipelago ?r\gh\t ! great] "p ( ! nor!rn hemisph]e4 ,sir ,*>les ,lyell is !re=e ( op9ion t ! climate ( ^! isl&s mu/ h be5 suffici5tly mild1 9 consequ5ce ( ! surr\nd+ ocean1 to clo! !m ) tropical plants1 & r5d] !m a fit abode = ! huge animals ^: fossil rema9s are s (t5 f\nd2 t ! arboresc5t f]ns & ! palms ( ^! regions1 c>ri$ by /reams to ! bottom ( ! ocean1 7 imb$d$ 9 ! /rata :i* 7 by degrees heav$ up by ! subt]ranean fires dur+ a long succession ( ages1 till ! great] "p ( ! nor!rn hemisph]e became dry l& z x n[ is1 & t ! consequ5ce has be5 a cont9ual decrease ( temp]ature4 ,x is evid5t1 f ! m>9e %ells f\nd on ! tops ( ! highe/ m\nta9s & 9 almo/ e "p ( ! globe1 t imm5se cont95ts h be5 elevat$ above ! ocean :i* mu/ h engulf$ o!rs4 ,su* a cata/rophe w\ld be occasion$ by a v>iation 9 ! position ( ! axis ( rotation on ! surface ( ! e>?2 = ! seas t5d+ to a new equator w\ld leave "s portions ( ! globe & ov]:elm o!rs4 ,n[1 x is f\nd by ! laws ( me*anics t 9 e body1 be its =m or d5sity :at x may1 !re are at lea/ ?ree axes at "r angles to ea* o!r1 r\nd any "o ( :i*1 if ! solid beg9s to rotate1 x w cont9ue to revolve = ev]1 provid$ x be n di/urb$ by a =eign cause1 b t ! rotation ab\t any o!r axis w only be = an in/ant1 & consequ5tly ! poles or extremities ( ! in/antane\s axis ( rotation w\ld p]petually *ange _! position on ! surface ( ! body4 ,9 an ellipsoid ( revolution ! pol> diamet] & e diamet] 9 ! plane ( ! equator are ! only p]man5t axes ( rotation 7,n4 #ade74 ,h5ce1 if ! ellipsoid 7 to beg9 to revolve ab\t any diamet] betwe5 ! pole & ! equator1 ! motion w\ld be s un/able t ! axis ( rotation & ! position ( ! poles w\ld *ange e in/ant4 ,!re=e1 z ! e>? does n diff] mu* f ?is figure1 if x did n turn r\nd "o ( its pr9cipal axes1 ! position ( ! poles w\ld *ange daily2 ! equator1 :i* is #ij di/ant1 w\ld und]go correspond+ v>iations2 & ! geographical latitudes ( all places1 be+ e/imat$ f ! equator1 assum$ to be fix$1 w\ld be p]petually *ang+4 ,a displacem5t 9 ! position ( ! poles ( only two hundr$ miles w\ld be suffici5t to produce ^! effects1 & w\ld imm$iately be detect$4 ,b1 z ! latitudes are f\nd to be inv>iable1 x may be conclud$ t ! t]re/rial sph]oid mu/ h revolv$ ab\t ! same axis = ages4 ,! e>? & planets diff] s little f ellipsoids ( revolution1 t 9 all probability any libration f "o axis to ano!r1 produc$ by ! primitive impulse :i* put !m 9 motion1 mu/ h ceas$ soon aft] _! creation f ! friction ( ! fluids at _! surface4 ,!ory also proves t nei!r nutation1 precession1 nor any ( ! di/urb+ =ces t affect ! sy/em1 h ! smalle/ influ5ce on ! axis ( rotation1 :i* ma9ta9s a p]man5t position on ! surface1 if ! e>? be n di/urb$ 9 its rotation by a =eign cause1 z ! collision ( a comet1 :i* might h happ5$ 9 ! imm5sity ( "t4 ,b1 _h t be5 ! case1 its effects w\ld /ill h be5 p]ceptible 9 ! v>iations ( ! geographical latitudes4 ,if we suppose t su* an ev5t _h tak5 place1 & t ! di/urbance _h be5 v great1 equilibrium c\ld !n only h be5 re/or$ ) reg>d to a new axis ( rotation by ! ru%+ ( ! seas to ! new equator1 :i* !y mu/ h cont9u$ to d till ! surface 0 ev]y:]e p]p5dicul> to ! direction ( gravity4 ,b x is probable t su* an accumulation ( ! wat]s w\ld n be suffici5t to re/ore equilibrium if ! d]angem5t _h be5 great1 = ! mean d5sity ( ! sea is only ab\t a fif? "p ( ! mean d5sity ( ! e>?1 & ! mean dep? ( ! ,pacific ,ocean is suppos$ n to be m ?an f\r or five miles1 :]eas ! equatorial diamet] ( ! e>? exce$s ! pol> diamet] by ab\t #bf-a_/b miles4 ,consequ5tly ! influ5ce ( ! sea on ! direction ( gravity is v small4 ,&1 z x ?us appe>s t a great *ange 9 ! position ( ! axis is incompatible ) ! law ( equilibrium1 ! geological ph5om5a 9 "q mu/ be ascrib$ to an int]nal cause4 ,inde$ x is n[ demon/rat$ t ! /rata conta9+ m>9e diluvia1 :i* are 9 l(ty situations1 mu/ h be5 =m$ at ! bottom ( ! ocean1 & aft]w>ds upheav$ by ! action ( subt]rane\s fires4 ,besides1 x is cle>1 f ! m5suration ( ! arcs ( ! m]idian & ! l5g? ( ! seconds' p5dulum1 z well z f ! lun> !ory1 t ! int]nal /rata & also ! ext]nal outl9e ( ! globe are elliptical1 _! c5tres be+ co9cid5t & _! axes id5tical ) t ( ! surface--a /ate ( ?+s :i*1 accord+ to ! di/+ui%$ au?or lately quot$1 is incompatible ) a subsequ5t accommodation ( ! surface to a new & diff]5t /ate ( rotation f t :i* det]m9$ ! orig9al di/ribution ( ! compon5t matt]4 ,?us1 amid/ ! mighty revolutions :i* h swept innum]able races ( organiz$ be+s f ! e>?1 :i* h elevat$ pla9s & buri$ m\nta9s 9 ! ocean1 ! rotation ( ! e>? & ! position ( ! axes on its surface h und]gone b slight v>iations4 ,! /rata ( ! t]re/rial sph]oid are n only conc5tric & elliptical1 b ! lun> inequalities %[ t !y increase 9 d5sity f ! surface ( ! e>? to its c5tre4 ,?is w\ld c]ta9ly h happ5$ if ! e>? _h orig9ally be5 fluid1 = ! d5s] p>ts mu/ h subsid$ t[>ds ! c5tre z x approa*$ a /ate ( equilibrium4 ,b ! enorm\s pressure ( ! sup]9cumb5t mass is a suffici5t cause = ! ph5om5on4 ,pr(essor ,leslie obs]ves t air compress$ into ! fiftie? "p ( its volume has its ela/icity fifty times augm5t$4 ,if x cont9ues to contract at t rate1 x w\ld1 f its own incumb5t weight1 acquire ! d5sity ( wat] at ! dep? ( ?irty-f\r miles4 ,b wat] itself w\ld h its d5sity d\bl$ at ! dep? ( n9ety-?ree miles1 & w\ld ev5 atta9 ! d5sity ( quicksilv] at a dep? ( #cfb miles4 ,desc5d+ !re=e t[>ds ! c5tre ?r\gh ne>ly #djjj miles1 ! cond5sation ( ord9>y sub/ances w\ld surpass ! utmo/ p[]s ( conception4 ,dr4 ,"y says t /eel w\ld be compress$ into "o-f\r? & /one into "o-eigh? ( its bulk at ! e>?'s c5tre4 ,h[ev]1 we are yet ignorant ( ! laws ( compression ( solid bodies beyond a c]ta9 limit2 f ! exp]im5ts ( ,mr4 ,p]k9s !y appe> to be capable ( a great] degree ( compression ?an has g5]ally be5 imag9$4 ,b a d5sity s extreme is n borne out by a/ronomical obs]vation4 ,x might seem to foll[ !re=e t our planet mu/ h a widely cav]n\s /ructure1 & t we tread on a cru/ or %ell ^: ?ickness be>s a v small proportion to ! diamet] ( its sph]e4 ,possibly1 too1 ?is great cond5sation at ! c5tral regions may be c\nt]balanc$ by ! increas$ ela/icity due to a v elevat$ temp]ature4 ,,section ,,xi4 ,precession & ,nutation--,_! ,effects on ! ,app>5t ,places ( ! ,fix$ ,/>s4 ,,x has be5 %[n t ! axis ( rotation is inv>iable on ! surface ( ! e>?2 & obs]vation z well z !ory prove t1 7 x n = ! action ( ! sun & moon on ! matt] at ! equator1 x w\ld rema9 exactly p>allel to itself 9 e po9t ( its orbit4 ,! attraction ( an ext]nal body n only draws a sph]oid t[>ds x1 b1 z ! =ce v>ies inv]sely z ! squ>e ( ! di/ance1 x gives x a motion ab\t its c5tre ( gravity1 unless :5 ! attract+ body is situat$ 9 ! prolongation ( "o ( ! axes ( ! sph]oid4 ,! plane ( ! equator is incl9$ to ! plane ( ! ecliptic at an angle ( #bc #bg #bhbi2 & ! incl9ation ( ! lun> orbit to ! same is #e #h #dgi4 ,consequ5tly1 f ! oblate figure ( ! e>?1 ! sun & moon1 act+ obliquely & unequally on ! diff]5t p>ts ( ! t]re/rial sph]oid1 urge ! plane ( ! equator f its direction1 & =ce x to move f ea/ to we/1 s t ! equ9octial po9ts h a sl[ retrograde motion on ! plane ( ! ecliptic ( #ejda annually4 ,! direct t5d5cy ( ?is action is to make ! planes ( ! equator & ecliptic co9cide1 b x is balanc$ by ! t5d5cy ( ! e>? to return to /able rotation ab\t ! pol> diamet]1 :i* is "o ( its pr9cipal axes ( rotation4 ,!re=e ! incl9ation ( ! two planes rema9s con/ant1 z a top sp9n+ pres]ves ! same incl9ation to ! plane ( ! horizon4 ,7 ! e>? sph]ical1 ?is effect w\ld n be produc$1 & ! equ9oxes w\ld always correspond ) ! same po9ts ( ! ecliptic1 at lea/ z f> z ?is k9d ( motion is conc]n$4 ,b ano!r & totally diff]5t cause :i* op]ates on ?is motion has already be5 m5tion$4 ,! action ( ! planets on "o ano!r & on ! sun occasions a v sl[ v>iation 9 ! position ( ! plane ( ! ecliptic1 :i* affects its incl9ation to ! plane ( ! equator1 & gives ! equ9octial po9ts a sl[ b direct motion on ! ecliptic ( #jca annually1 :i* is entirely indep5d5t ( ! figure ( ! e>?1 & w\ld be ! same if x 7 a sph]e4 ,?us ! sun & moon by mov+ ! plane ( ! equator cause ! equ9octial po9ts to retrograde on ! ecliptic3 & ! planets by mov+ ! plane ( ! ecliptic give !m a direct motion1 ?\gh mu* less ?an ! =m]4 ,consequ5tly ! diff]5ce ( ! two is ! mean precession1 :i* is prov$ bo? by !ory & obs]vation to be ab\t #eja annually 7,n4 #adf74 ,z ! longitudes ( all ! fix$ />s are increas$ by ?is quantity1 ! effects ( precession are soon detect$4 ,x 0 accord+ly discov]$ by ,hipp>*us 9 ! ye> #abh be=e ,*ri/1 f a comp>ison ( 8 own obs]vations ) ^? ( ,timo*>is #aee ye>s be=e4 ,9 ! "t ( ,hipp>*us ! entrance ( ! sun into ! con/ellation ,aries 0 ! beg9n+ ( spr+2 b s9ce t "t ! equ9octial po9ts h rec$$ #cj1 s t ! con/ellations call$ ! signs ( ! zodiac are n[ at a consid]able di/ance f ^? divisions ( ! ecliptic :i* be> _! names4 ,mov+ at ! rate ( #eja annually1 ! equ9octial po9ts w accompli% a revolution 9 #be1hfh ye>s4 ,b1 z ! precession v>ies 9 diff]5t c5turies1 ! ext5t ( ?is p]iod w be slightly modifi$4 ,s9ce ! motion ( ! sun is direct1 & t ( ! equ9octial po9ts retrograde1 he takes a %ort] "t to return to ! equator ?an to arrive at ! same />s2 s t ! tropical ye> ( #cfe;d #e;h #dhm #dis#g mu/ be increas$ by ! "t he takes to move ?r\gh an arc ( #eja1 9 ord] to h ! l5g? ( ! sid]eal ye>4 ,! "t requir$ is #bjm #ais#f1 s t ! sid]eal ye> conta9s #cfe;d #f;h #im #is#f mean sol> days4 ,! mean annual precession is subject to a secul> v>iation2 =1 al?\gh ! *ange 9 ! plane ( ! ecliptic 9 :i* ! orbit ( ! sun lies be indep5d5t ( ! =m ( ! e>?1 yet1 by br++ ! sun1 moon1 & e>? into diff]5t relative positions f age to age1 x alt]s ! direct action ( ! two fir/ on ! prom95t matt] at ! equator3 on ?is acc\nt ! motion ( ! equ9ox is great] by #jdee n[ ?an x 0 9 ! "t ( ,hipp>*us4 ,consequ5tly ! actual l5g? ( ! tropical ye> is ab\t #ds#ba %ort] ?an x 0 at t "t4 ,! utmo/ *ange t x c exp]i5ce f ?is cause am\nts to #dc seconds4 ,su* is ! secul> motion ( ! equ9oxes4 ,b x is sometimes increas$ & sometimes dim9i%$ by p]iodic v>iations1 ^: p]iods dep5d ^u ! relative positions ( ! sun & moon ) reg>d to ! e>?1 & :i* are occasion$ by ! direct action ( ^! bodies on ! equator4 ,dr4 ,bradley discov]$ t by ?is action ! moon causes ! pole ( ! equator to describe a small ellipse 9 ! heav5s1 ! axes ( :i* are #ahe & #acfgd1 ! long] be+ direct$ t[>ds ! pole ( ! ecliptic4 ,! p]iod ( ?is inequality is ab\t #ai ye>s1 ! "t employ$ by ! nodes ( ! lun> orbit to accompli% a revolution4 ,! sun causes a small v>iation 9 ! description ( ?is ellipse2 x runs ?r\gh its p]iod 9 half a ye>4 ,s9ce ! :ole e>? obeys ^! motions1 !y affect ! position ( its axis ( rotation ) reg>d to ! />ry heav5s1 ?\gh n ) reg>d to ! surface ( ! e>?2 = 9 consequ5ce ( precession alone ! pole ( ! equator moves 9 a circle r\nd ! pole ( ! ecliptic 9 #be1hfh ye>s1 & by nutation alone x describes a small ellipse 9 ! heav5s e #ai ye>s1 on ea* side ( :i* x deviates e half-ye> f ! action ( ! sun4 ,! real curve trac$ 9 ! />ry heav5s by ! imag9>y prolongation ( ! e>?'s axis is comp\nd$ ( ^! ?ree motions 7,n4 #adg74 ,?is nutation 9 ! e>?'s axis affects bo? ! precession & obliquity ) small p]iodic v>iations4 ,b 9 consequ5ce ( ! secul> v>iation 9 ! position ( ! t]re/rial orbit1 :i* is *iefly ow+ to ! di/urb+ en]gy ( ,jupit] on ! e>?1 ! obliquity ( ! ecliptic is annually dim9i%$1 accord+ to ,m4 ,bessel1 by #jdeg4 ,?is v>iation 9 ! c\rse ( ages may am\nt to #aj or #aa degrees2 b ! obliquity ( ! ecliptic to ! equator c nev] v>y m ?an #b #db or #c1 s9ce ! equator w foll[ 9 "s measure ! motion ( ! ecliptic4 ,x is evid5t t ! places ( all ! cele/ial bodies are affect$ by precession & nutation4 ,_! longitudes e/imat$ f ! equ9ox are augm5t$ by precession2 b1 z x affects all ! bodies equally1 x makes no *ange 9 _! relative positions4 ,bo? ! cele/ial latitudes & longitudes are alt]$ to a small degree by nutation2 h5ce all obs]vations mu/ be correct$ = ^! inequalities4 ,9 consequ5ce ( ?is real motion 9 ! e>?'s axis1 ! pole-/>1 =m+ "p ( ! con/ellation ( ! ,little ,be>1 :i* 0 =m]ly #ab f ! cele/ial pole1 is n[ )9 #a #bd ( x1 & w cont9ue to approa* x till x is )9 #a_/b1 aft] :i* x w retreat f ! pole = ages2 & #ab1icd ye>s h5ce ! /> ,lyr w come )9 #e ( ! cele/ial pole1 & become ! pol> /> ( ! nor!rn hemisph]e4 ,,section ,,xii4 ,mean & ,app>5t ,sid]eal ,"t--,mean & ,app>5t ,sol> ,"t--,equation ( ,"t--,engli% & ,fr5* ,subdivisions ( ,"t--,leap ,ye>--,*ri/ian ,era--,equ9octial ,"t--,rem>kable ,eras dep5d+ ^u ! ,position ( ! ,sol> ,p]igee--,inequality ( ! ,l5g?s ( ! ,seasons 9 ! two ,hemisph]es--,application ( ,a/ronomy to ,*ronology--,engli% & ,fr5* ,/&>ds ( ,weights & ,measures4 ,,a/ronomy has be5 ( imm$iate & ess5tial use 9 af=d+ inv>iable /&>ds = measur+ duration1 di/ance1 magnitude1 & velocity4 ,! mean sid]eal day measur$ by ! "t elaps$ betwe5 two consecutive transits ( any /> at ! same m]idian 7,n4 #adh71 & ! mean sid]eal ye> :i* is ! "t includ$ betwe5 two consecutive returns ( ! sun to ! same />1 are immutable units ) :i* all great p]iods ( "t are comp>$2 ! oscillations ( ! iso*ron\s p5dulum measure its small] portions4 ,by ^! inv>iable /&>ds alone we c judge ( ! sl[ *anges t o!r elem5ts ( ! sy/em may h und]gone4 ,app>5t sid]eal "t1 :i* is measur$ by ! transit ( ! equ9octial po9t at ! m]idian ( any place1 is a v>iable quantity1 f ! effects ( precession & nutation4 ,clocks %[+ app>5t sid]eal "t are employ$ = obs]vation1 & are s regulat$ t !y indicate #j;h #jm #js at ! in/ant ! equ9octial po9t passes ! m]idian ( ! obs]vatory4 ,& z "t is a measure ( angul> motion1 ! clock gives ! di/ances ( ! heav5ly bodies f ! equ9ox by obs]v+ ! in/ant at :i* ea* passes ! m]idian1 & conv]t+ ! int]val into arcs at ! rate ( #ae to an h\r4 ,! returns ( ! sun to ! m]idian & to ! same equ9ox or sol/ice h be5 univ]sally adopt$ z ! measure ( our civil days & ye>s4 ,! sol> or a/ronomical day is ! "t t elapses betwe5 two consecutive noons or midnights4 ,x is consequ5tly long] ?an ! sid]eal day1 on acc\nt ( ! prop] motion ( ! sun dur+ a revolution ( ! cele/ial sph]e4 ,b1 z ! sun moves ) great] rapidity at ! w9t] ?an at ! summ] sol/ice1 ! a/ronomical day is m ne>ly equal to ! sid]eal day 9 summ] ?an 9 w9t]4 ,! obliquity ( ! ecliptic also affects its duration2 = ne> ! equ9oxes ! arc ( ! equator is less ?an ! correspond+ arc ( ! ecliptic1 & 9 ! sol/ices x is great] 7,n4 #adi74 ,! a/ronomical day is !re=e dim9i%$ 9 ! fir/ case1 & increas$ 9 ! second4 ,if ! sun mov$ uni=mly 9 ! equator at ! rate ( #ei #hcc e day1 ! sol> days w\ld be all equal4 ,! "t !re=e :i* is reckon$ by ! arrival ( an imag9>y sun at ! m]idian1 or ( "o :i* is suppos$ to move uni=mly 9 ! equator1 is d5om9at$ mean sol> "t1 & is giv5 by clocks & wat*es 9 common life4 ,:5 x is reckon$ by ! arrival ( ! real sun at ! m]idian1 x is true or app>5t "t1 & is giv5 by dials4 ,! diff]5ce betwe5 ! "t %[n by a clock & a dial is ! equation ( "t giv5 9 ! ,nautical ,almanac1 sometimes am\nt+ to z mu* z sixte5 m9utes4 ,! app>5t & mean "t co9cide f\r times 9 ! ye>2 :5 ! sun's daily motion 9 "r asc5sion is equal to #ei #hcc 9 a mean sol> day1 :i* happ5s ab\t ! #af? ( ,april1 ! #af? ( ,june1 ! #a/ ( ,septemb]1 & ! #be? ( ,decemb]4 ,! a/ronomical day beg9s at noon1 b 9 common reckon+ ! day beg9s at midnight4 ,9 ,engl& x is divid$ into tw5ty-f\r h\rs1 :i* are c\nt$ by twelve & twelve2 b 9 ,france a/ronom]s1 adopt+ ! decimal division1 divide ! day into t5 h\rs1 ! h\r into "o hundr$ m9utes1 & ! m9ute into a hundr$ seconds1 because ( ! facility 9 computation1 & 9 con=mity ) _! decimal sy/em ( weights & measures4 ,?is subdivision is n n[ us$ 9 common life1 nor has x be5 adopt$ 9 any o!r c\ntry2 & al?\gh "s sci5tific writ]s 9 ,france /ill employ t division ( "t1 ! cu/om is beg9n+ to we> out4 ,at "o p]iod dur+ ! ,fr5* ,revolution1 ! clock 9 ! g>d5s ( ! ,tuil]ies 0 regulat$ to %[ decimal "t4 ,! mean l5g? ( ! day1 ?\gh accurately det]m9$1 is n suffici5t = ! purposes ei!r ( a/ronomy or civil life4 ,! tropical or civil ye> ( #cfe;d #e;h #dhm #dis#g1 :i* is ! "t elaps$ betwe5 ! consecutive returns ( ! sun to ! mean equ9oxes or sol/ices1 includ+ all ! *anges ( ! seasons1 is a natural cycle peculi>ly suit$ = a measure ( duration4 ,x is e/imat$ f ! w9t] sol/ice1 ! middle ( ! long annual night "u ! nor? pole4 ,b al?\gh ! l5g? ( ! civil ye> is po9t$ out by nature z a measure ( long p]iods1 ! incomm5surability t exi/s betwe5 ! l5g? ( ! day & ! revolution ( ! sun r5d]s x difficult to adju/ ! e/imation ( bo? 9 :ole numb]s4 ,if ! revolution ( ! sun 7 accompli%$ 9 #cfe days1 all ! ye>s w\ld be ( precisely ! same numb] ( days1 & w\ld beg9 & end ) ! sun at ! same po9t ( ! ecliptic4 ,b z ! sun's revolution includes ! fraction ( a day1 a civil ye> & a revolution ( ! sun h n ! same duration4 ,s9ce ! fraction is ne>ly ! f\r? ( a day1 9 f\r ye>s x is ne>ly equal to a revolution ( ! sun1 s t ! addition ( a sup]num]>y day e f\r? ye> ne>ly comp5sates ! diff]5ce4 ,b 9 process ( "t fur!r correction w be necess>y1 because ! fraction is less ?an ! f\r? ( a day4 ,9 fact1 if a bissextile be suppress$ at ! end ( ?ree out ( f\r c5turies1 ! ye> s det]m9$ w only exce$ ! true ye> by an extremely small fraction ( a day2 & if 9 addition to ?is a bissextile be suppress$ e #djjj ye>s1 ! l5g? ( ! ye> w be ne>ly equal to t giv5 by obs]vation4 ,7 ! fraction neglect$1 ! beg9n+ ( ! ye> w\ld prec$e t ( ! tropical ye>1 s t x w\ld retrograde ?r\gh ! diff]5t seasons 9 a p]iod ( ab\t #aejg ye>s4 ,! ,egyptian ye> began ) ! heliacal ris+ ( ,sirius 7,n4 #aej71 & conta9$ only #cfe days1 by :i* !y lo/ "o ye> 9 e #adfa ye>s1 _! ,so?aic p]iod1 or t cycle 9 :i* ! heliacal ris+ ( ,sirius passes ?r\gh ! :ole ye> & takes place aga9 on ! same day4 ,! division ( ! ye> into mon?s is v old & almo/ univ]sal4 ,b ! p]iod ( sev5 days1 by f> ! mo/ p]man5t division ( "t1 & ! mo/ anci5t monum5t ( a/ronomical k1 0 us$ by ! ,brahm9s 9 ,india ) ! same d5om9ations employ$ by u1 & 0 alike f\nd 9 ! cal5d>s ( ! ,jews1 ,egyptians1 ,arabs1 & ,assyrians4 ,x has surviv$ ! fall ( empires1 & has exi/$ among all successive g5]ations1 a pro( ( _! common orig94 ,! day ( ! new moon imm$iately foll[+ ! w9t] sol/ice 9 ! #gjg? ye> ( ,rome 0 made ! #a/ ( ,janu>y ( ! fir/ ye> ( ,julius ,cs>4 ,! #be? ( ,decemb] ( 8 =ty-fif? ye> is consid]$ z ! date ( ,*ri/'s nativity2 & ! =ty-six? ye> ( ! ,julian ,cal5d> is assum$ to be ! fir/ ( our era4 ,! prec$+ ye> is call$ ! fir/ ye> be=e ,*ri/ by *ronologi/s1 b by a/ronom]s x is call$ ! ye> #j4 ,! a/ronomical ye> beg9s on ! #ca/ ( ,decemb] at noon2 & ! date ( an obs]vation expresses ! days & h\rs :i* h actually elaps$ s9ce t "t4 ,s9ce sol> & sid]eal "t are e/imat$ f ! passage ( ! sun & ! equ9octial po9t across ! m]idian ( ea* place1 ! h\rs are diff]5t at diff]5t places3 :ile x is "o o'clock at "o place1 x is two at ano!r1 ?ree at ano!r1 c42 = x is obvi\s t x is noon at "o "p ( ! globe at ! same mom5t t x is midnight at ano!r diametrically opposite to x3 consequ5tly an ev5t :i* happ5s at "o & ! same in/ant ( absolute "t is record$ at diff]5t places z hav+ happ5$ at diff]5t times4 ,!re=e1 :5 obs]vations made at diff]5t places are to be comp>$1 !y mu/ be r$uc$ by computation to :at !y w\ld h be5 _h !y be5 made "u ! same m]idian4 ,to obviate ?is x 0 propos$ by ,sir ,john ,h]s*el to employ mean equ9octial "t1 :i* is ! same = all ! _w1 & indep5d5t alike ( local circum/ances & inequalities 9 ! sun's motion4 ,x is ! "t elaps$ f ! in/ant ! mean sun ent]s ! mean v]nal equ9ox1 & is reckon$ 9 mean sol> days & p>ts ( a day4 ,"s rem>kable a/ronomical eras are det]m9$ by ! position ( ! major axis ( ! sol> ellipse1 :i* dep5ds ^u ! direct motion ( ! p]igee 7,n4 #ajb7 & ! precession ( ! equ9oxes conjo9tly1 ! annual motion ( ! "o be+ #aah1 & t ( ! o!r #eja4 ,h5ce ! axis1 mov+ at ! rate ( #fai annually1 accompli%es a tropical revolution 9 #bjihd ye>s4 ,x co9cid$ ) ! l9e ( ! equ9oxes #djjj or #djhi ye>s be=e ! ,*ri/ian era1 mu* ab\t ! "t *ronologi/s assign = ! creation ( man4 ,9 #fdhc ! major axis w aga9 co9cide ) ! l9e ( ! equ9oxes2 b !n ! sol> p]igee w co9cide ) ! equ9ox ( autumn1 :]eas at ! creation ( man x co9cid$ ) ! v]nal equ9ox4 ,9 ! ye> #abdf ! major axis 0 p]p5dicul> to ! l9e ( ! equ9oxes2 !n ! sol> p]igee co9cid$ ) ! sol/ice ( summ]1 & ! apogee ) ! sol/ice ( w9t]4 ,accord+ to ,la ,place1 :o comput$ ^! p]iods f diff]5t data1 ! la/ co9cid5ce happ5$ 9 ! ye> #abej ( our era1 :i* induc$ him to propose t ye> z a univ]sal epo*1 ! v]nal equ9ox ( ! ye> #abej to be ! fir/ day ( ! fir/ ye>4 ,^! eras c only be reg>d$ z approximate1 s9ce anci5t obs]vations are too inaccurate1 & mod]n obs]vations too rec5t1 to af=d data = _! precise det]m9ation4 ,! v>iation 9 ! position ( ! sol> ellipse occasions correspond+ *anges 9 ! l5g? ( ! seasons4 ,9 its pres5t position spr+ is %ort] ?an summ]1 & autumn long] ?an w9t]2 & :ile ! sol> p]igee cont9ues z x n[ is1 betwe5 ! sol/ice ( w9t] & ! equ9ox ( spr+1 ! p]iod includ+ spr+ & summ] w be long] ?an t includ+ autumn & w9t]4 ,9 ?is c5tury ! diff]5ce is betwe5 sev5 & eight days4 ,! int]vals w be equal t[>ds ! ye> #fdhc1 :5 ! p]igee w co9cide ) ! equ9ox ( spr+2 b1 :5 x passes t po9t1 ! spr+ & summ] tak5 toge!r w be %ort] ?an ! p]iod includ+ ! autumn & w9t] 7,n4 #aea74 ,^! *anges w be accompli%$ 9 a tropical revolution ( ! major axis ( ! e>?'s orbit1 :i* includes an int]val ( #bj1ihd ye>s4 ,7 ! orbit circul>1 ! seasons w\ld be equal2 _! diff]5ce arises f ! exc5tricity ( ! orbit1 small z x is2 b ! *anges are s trifl+ z to be imp]ceptible 9 ! %ort span ( human life4 ,no circum/ance 9 ! :ole sci5ce ( a/ronomy excites a deep] int]e/ ?an its application to *ronology4 8,:ole nations10 says ,la ,place1 8h be5 swept f ! e>?1 ) _! languages1 arts1 & sci5ces1 leav+ b confus$ masses ( ru9s to m>k ! place :]e mighty cities /ood2 _! hi/ory1 ) ! exception ( a few d\btful traditions1 has p]i%$2 b ! p]fection ( _! a/ronomical obs]vations m>ks _! high antiquity1 fixes ! p]iods ( _! exi/5ce1 & proves t1 ev5 at t e>ly "t1 !y mu/ h made consid]able progress 9 sci5ce40 ,! anci5t /ate ( ! heav5s may n[ be comput$ ) great accuracy2 &1 by comp>+ ! results ( calculation ) anci5t obs]vations1 ! exact p]iod at :i* !y 7 made may be v]ifi$ if true1 or1 if false1 _! error may be detect$4 ,if ! date be accurate & ! obs]vation good1 x w v]ify ! accuracy ( mod]n tables1 & w %[ to h[ _m c5turies !y may be ext5d$ )\t ! fe> ( error4 ,a few examples w %[ ! importance ( ! subject4 ,at ! sol/ices ! sun is at 8 greate/ di/ance f ! equator2 consequ5tly 8 decl9ation at ^! times is equal to ! obliquity ( ! ecliptic 7,n4 #aeb71 :i* 0 =m]ly det]m9$ f ! m]idian l5g? ( ! %ad[ ( ! /ile ( a dial on ! day ( a sol/ice4 ,! l5g?s ( ! m]idian %ad[ at ! summ] & w9t] sol/ices are record$ to h be5 obs]v$ at ! city ( ,layang1 9 ,*9a1 #aajj ye>s be=e ! ,*ri/ian era4 ,f ^! ! di/ances ( ! sun f ! z5i? 7,n4 #aec7 ( ! city ( ,layang are kn[n4 ,half ! sum ( ^! z5i? di/ances det]m9es ! latitude1 & half _! diff]5ce gives ! obliquity ( ! ecliptic at ! p]iod ( ! obs]vation2 &1 z ! law ( ! v>iation ( ! obliquity is kn[n1 bo? ! "t & place ( ! obs]vations h be5 v]ifi$ by computations f mod]n tables4 ,?us ! ,*9ese _h made "s advances 9 ! sci5ce ( a/ronomy at t e>ly p]iod4 ,_! :ole *ronology is f\nd$ on ! obs]vations ( eclipses1 :i* prove ! exi/5ce ( t empire = m ?an #dgjj ye>s4 ,! epo* ( ! lun> tables ( ! ,indians1 suppos$ by ,bailly to be #cjjj ye>s be=e ! ,*ri/ian era1 0 prov$ by ,la ,place1 f ! accel]ation ( ! moon1 n to be m anci5t ?an ! "t ( ,ptolemy1 :o liv$ 9 ! second c5tury aft] x4 ,! great inequality ( ,jupit] & ,saturn1 ^: cycle embraces #iah ye>s1 is peculi>ly fitt$ = m>k+ ! civilization ( a p4 ,! ,indians _h det]m9$ ! mean motions ( ^! two planets 9 t "p ( _! p]iods :5 ! app>5t mean motion ( ,saturn 0 at ! sl[e/1 & t ( ,jupit] ! mo/ rapid4 ,! p]iods 9 :i* t happ5$ 7 #cajb ye>s be=e ! ,*ri/ian era1 & ! ye> #adia aft] x4 ,! returns ( comets to _! p]ihelia may possibly m>k ! pres5t /ate ( a/ronomy to future ages4 ,! places ( ! fix$ />s are affect$ by ! precession ( ! equ9oxes2 &1 z ! law ( t v>iation is kn[n1 _! positions at any "t may be comput$4 ,n[ ,eudoxus1 a contempor>y ( ,plato1 m5tions a /> situate 9 ! pole ( ! equator1 & x appe>s f computation t ,draconis 0 n v f> f t place ab\t #cjjj ye>s ago2 b1 z x is only ab\t #baej ye>s s9ce ,eudoxus liv$1 he mu/ h describ$ an ant]ior /ate ( ! heav5s1 suppos$ to be ! same t 0 m5tion$ by ,*iron ab\t ! "t ( ! siege ( ,troy4 ,?us e circum/ance concurs 9 %[+ t a/ronomy 0 cultivat$ 9 ! highe/ ages ( antiquity4 ,x is possible t a k ( a/ronomy may lead to ! int]pretation ( hi]oglyphical *>act]s4 ,a/ronomical signs are (t5 f\nd on ! anci5t ,egyptian monum5ts1 probably employ$ by ! prie/s to record dates4 ,! au?or _h occasion to witness an in/ance ( ?is mo/ int]e/+ application ( a/ronomy1 9 asc]ta9+ ! date ( a papyrus1 s5t f ,egypt by ,mr4 ,salt1 9 ! hi]oglyphical rese>*es ( ! late ,dr4 ,?omas ,"y1 ^: pr(\nd & v>i$ acquirem5ts d hon\r to 8 c\ntry1 & to ! age 9 :i* he liv$4 ,! manuscript 0 f\nd 9 a mummy case2 x prov$ to be a horoscope ( ! age ( ,ptolemy1 & its date 0 det]m9$ f ! configuration ( ! heav5s at ! "t ( its con/ruction4 ,! =m ( ! e>? furni%es a /&>d ( weights & measures = ! ord9>y purposes ( life1 z well z = ! det]m9ation ( ! masses & di/ances ( ! heav5ly bodies4 ,! l5g? ( ! p5dulum vibrat+ seconds ( mean sol> "t1 9 ! latitude ( ,london1 =ms ! /&>d ( ! ,briti% measure ( ext5sion4 ,its approximate l5g? oscillat+ 9 vacuo at ! temp]ature ( #fb ( ,fahr5heit1 & r$uc$ to ! level ( ! sea 7,n4 #aed71 0 det]m9$ by ,capta9 ,kat] to be #ciacic in*es4 ,! weight ( a cubic in* ( wat] at ! temp]ature ( #fb ( ,fahr5heit1 b>omet] #cj in*es1 0 also det]m9$ 9 p>ts ( ! imp]ial troy p\nd1 :5ce a /&>d bo? ( weight & capacity 0 d$uc$4 ,! ,fr5* h adopt$ ! mtre1 equal to #cbhjhiib ,engli% feet1 = _! unit ( l9e> measure1 :i* is ! t5-million? "p ( ! arc ( ! m]idian :i* ext5ds f ! equator to ! pole1 z d$uc$ f ! measures ( ! sep>ate arc ext5d+ f ,=m5t]a1 ! mo/ s\!rn ( ! ,bale>ic ,isl&s1 to ,dunkirk4 ,%\ld ! national /&>ds ( ! two c\ntries ev] be lo/1 bo? may be recov]$1 s9ce !y are d]iv$ f natural & inv>iable ones4 ,! l5g? ( ! measure d$uc$ f t ( ! p5dulum w\ld be f\nd aga9 ) m facility ?an ! mtre4 ,b1 z no measure is ma!matically exact1 an error 9 ! orig9al /&>d may at l5g? become s5sible 9 measur+ a great ext5t1 :]eas ! error t mu/ necess>ily arise 9 measur+ ! quadrant ( ! m]idian 7,n4 #aee7 is r5d]$ totally ins5sible by subdivision 9 tak+ its t5-million? "p4 ,! ,fr5* h adopt$ ! decimal division1 n only 9 "t1 b also 9 _! degrees1 weights1 & measures1 on acc\nt ( ! v great facility x af=ds 9 computation4 ,x has n be5 adopt$ by any o!r c\ntry1 ?\gh no?+ is m desirable ?an t all nations %\ld concur 9 us+ ! same /&>ds1 n only on acc\nt ( conv5i5ce1 b z af=d+ a m def9ite idea ( quantity4 ,x is s+ul> t ! decimal division ( ! day1 ( space1 weights1 & measures1 0 employ$ 9 ,*9a #djjj ye>s ago2 & t at ! "t ,ibn ,junis made 8 obs]vations at ,cairo1 ab\t ! ye> #ajjj ( ! ,*ri/ian era1 ! ,arabs 7 9 ! habit ( employ+ ! vibrations ( ! p5dulum 9 _! a/ronomical obs]vations z a measure ( "t4 ,,section ,,xiii4 ,tides--,=ces t produce !m--,orig9 & ,c\rse ( ,tidal ,wave--,its ,spe$--,?ree k9ds ( ,oscillations 9 ! ,ocean--,! ,semidiurnal ,tides--,equ9octial ,tides--,effects ( ! ,decl9ation ( ! ,sun & ,moon--,!ory insuffici5t )\t ,obs]vation--,direction ( ! ,tidal ,wave--,height ( ,tides--,mass ( ,moon obta9$ f h] ,action on ! ,tides--,int]f]5ce ( ,undulations--,impossibility ( a ,univ]sal ,inundation--,curr5ts4 ,,"o ( ! mo/ imm$iate & rem>kable effects ( a gravitat+ =ce ext]nal to ! e>? is ! alt]nate rise & fall ( ! surface ( ! sea twice 9 ! c\rse ( a lun> day1 or #bd;h #ejm #bhs ( mean sol> "t4 ,z x dep5ds ^u ! action ( ! sun & moon1 x is class$ among a/ronomical problems1 ( :i* x is by f> ! mo/ difficult & its explanation ! lea/ satisfactory4 ,! =m ( ! surface ( ! ocean 9 equilibrio1 :5 revolv+ ) ! e>? r\nd its axis1 is an ellipsoid flatt5$ at ! poles2 b ! action ( ! sun & moon1 especially ( ! moon1 di/urbs ! equilibrium ( ! ocean4 ,if ! moon attract$ ! c5tre ( gravity ( ! e>? & all its p>ticles ) equal & p>allel =ces1 ! :ole sy/em ( ! e>? & ! wat]s t cov] x w\ld yield to ^! =ces ) a common motion1 & ! equilibrium ( ! seas w\ld rema9 undi/urb$4 ,! diff]5ce ( ! =ces & ! inequality ( _! directions alone di/urb ! equilibrium4 ,! p>ticles ( wat] "u ! moon are m attract$ ?an ! c5tre ( gravity ( ! e>?1 9 ! inv]se ratio ( ! squ>e ( ! di/ance4 ,h5ce !y h a t5d5cy to leave ! e>?1 b are reta9$ by _! gravitation1 :i* is dim9i%$ by ?is t5d5cy4 ,on ! contr>y1 ! moon attracts ! c5tre ( ! e>? m p[]fully ?an %e attracts ! p>ticles ( wat] 9 ! hemisph]e opposite to h]2 s t ! e>? has a t5d5cy to leave ! wat]s1 b is reta9$ by gravitation1 :i* is aga9 dim9i%$ by ?is t5d5cy4 ,?us ! wat]s imm$iately "u ! moon are drawn f ! e>?1 at ! same "t t ! e>? is drawn f ^? :i* are diametrically opposite to h]1 9 bo? in/ances produc+ an elevation ( ! ocean ( ne>ly ! same height above ! surface ( equilibrium2 = ! dim9ution ( ! gravitation ( ! p>ticles 9 ea* position is almo/ ! same1 on acc\nt ( ! di/ance ( ! moon be+ great 9 comp>ison ( ! radius ( ! e>?4 ,7 ! e>? entirely cov]$ by ! sea1 ! wat]s ?us attract$ by ! moon w\ld assume ! =m ( an oblong sph]oid ^: great] axis w\ld po9t t[>ds ! moon2 s9ce ! columns ( wat] "u ! moon1 & 9 ! direction diametrically opposite to h]1 are r5d]$ light] 9 consequ5ce ( ! dim9ution ( _! gravitation2 &1 9 ord] to pres]ve ! equilibrium1 ! axes #ij di/ant w\ld be %ort5$4 ,! elevation1 on acc\nt ( ! small] space to :i* x is conf9$1 is twice z great z ! depression1 because ! cont5ts ( ! sph]oid always rema9 ! same4 ,if ! wat]s 7 capable ( assum+ ! =m ( equilibrium in/antane\sly1 t is1 ! =m ( ! sph]oid1 its summit w\ld always po9t to ! moon not)/&+ ! e>?'s rotation4 ,b1 on acc\nt ( _! resi/ance1 ! rapid motion produc$ 9 !m by rotation prev5ts !m f assum+ at e in/ant ! =m :i* ! equilibrium ( ! =ces act+ ^u !m requires4 ,h5ce1 on acc\nt ( ! in]tia ( ! wat]s1 if ! tides be consid]$ relatively to ! :ole e>? & op5 seas1 !re is a m]idian ab\t #cj ea/w>d ( ! moon1 :]e x is always high wat] bo? 9 ! hemisph]e :]e ! moon is & 9 t :i* is opposite4 ,on ! we/ side ( ?is circle ! tide is fl[+1 on ! ea/ x is ebb+1 & on e "p ( ! m]idian at #ij di/ant x is l[ wat]4 ,?is great wave1 :i* foll[s all ! motions ( ! moon z f> z ! rotation ( ! e>? w p]mit1 is modifi$ by ! action ( ! sun1 ! effects ( ^: attraction are 9 e respect l ^? produc$ by ! moon1 ?\gh greatly less 9 degree4 ,consequ5tly a simil> wave1 b mu* small]1 rais$ by ! sun1 t5ds to foll[ 8 motions1 :i* at times comb9es ) ! lun> wave1 & at o!rs opposes x1 accord+ to ! relative positions ( ! two lum9>ies2 b z ! lun> wave is only modifi$ a little by ! sol>1 ! tides mu/ necess>ily happ5 twice 9 a day1 s9ce ! rotation ( ! e>? br+s ! same po9t twice "u ! m]idian ( ! moon 9 t "t1 once "u ! sup]ior & once "u ! inf]ior m]idian4 ,! p]iodic motions ( ! wat]s ( ! ocean1 on ! hypo!sis ( an ellipsoid ( revolution1 entirely cov]$ by ! sea1 are1 h[ev]1 v f> f accord+ ) obs]vation4 ,?is arises f ! great irregul>ities 9 ! surface ( ! e>?1 :i* is b p>tially cov]$ by ! sea1 f ! v>iety 9 ! dep?s ( ! ocean1 ! mann] 9 :i* x is spread out on ! e>?1 ! position & incl9ation ( ! %ores1 ! curr5ts1 & ! resi/ance :i* ! wat]s meet )3 causes impossible to e/imate g5]ally1 b :i* modify ! oscillations ( ! great mass ( ! ocean4 ,h[ev]1 amid/ all ^! irregul>ities1 ! ebb & fl[ ( ! sea ma9ta9 a ratio to ! =ces produc+ !m suffici5t to indicate _! nature1 & to v]ify ! law ( ! attraction ( ! sun & moon on ! sea4 ,la ,place obs]ves1 t ! inve/igation ( su* relations betwe5 cause & effect is no less useful 9 natural philosophy ?an ! direct solution ( problems1 ei!r to prove ! exi/5ce ( ! causes or to trace ! laws ( _! effects4 ,l ! !ory ( probabilities1 x is a happy supplem5t to ! ignorance & weakness ( ! human m9d4 ,s9ce ! di/urb+ action ( ! sun & moon c only become s5sible 9 a v great ext5t ( deep wat]1 ! ,ant>ctic ,ocean is ! orig9 & bir?place ( our tides4 ,a succession ( tidal waves f t s\rce foll[ "o ano!r 9 a nor?-we/]ly direction d[n ! ,pacific & ,atlantic ,oceans1 modifi$ z !y proce$ by ! dep? ( ! wat] & ! =m ( ! coa/s4 ,= :5 ! sun & moon are 9 ! same m]idian1 & pass ov] ! mass ( wat]s ly+ ea/ f ,van ,diem5's ,l&1 ,new ,zeal&1 & ! ,s\? ,pole1 ! result+ =ce ( _! comb9$ attraction1 p5etrat+ to ! abyss ( ! deep & b\ndless circuit ( ! ,s\!rn ,ocean1 raises a va/ wave or ridge ( wat]1 :i* t5ds to foll[ ! lum9>ies to ! nor? & we/1 & cont9ues to fl[ 9 t direction long aft] ! bodies cease to act ^u x2 b x is s ret>d$ by ! rotation ( ! e>? & by ! in]tia ( ! wat]1 t x does n arrive at ! diff]5t p>ts ( ! coa/s till aft] ! moon's s\?+ 7,n4 #aef74 ,:5 ?is tidal wave leaves ! ,ant>ctic ,ocean & ent]s ! ,pacific1 x ru%es along ! we/]n coa/ ( ,am]ica to its f>!/ end1 b x is s mu* ob/ruct$ by ! numb] ( isl&s 9 ! middle ( t ocean t x is h>dly p]ceptible among !m2 :ile on ! ea/ x ent]s ! ,indian ,ocean1 /rikes ) viol5ce on ! coa/s ( ,h9do/an & ! %ores at ! m\?s ( ! ,ganges1 & causes ! t]rific bore 9 ! ,hoogly4 ,! "p ( ?is tidal wave t ent]s ! ,atlantic passes impetu\sly along ! coa/s ( ,africa & ,am]ica1 arriv+ lat] & lat] at ea* place4 ,x is modifi$1 h[ev]1 by a tide rais$ 9 ! ,atlantic1 :i* is deep & free f isl&s2 & ?is comb9$ tidal wave1 /ill com+ nor?w>d1 p\rs its surge into ! ,gulf ( ,fundy to ! height ( fifty feet2 !n be+ deflect$ by ! coa/ ( ,am]ica at "r angles1 x ru%es ea/w>d1 br++ high wat] to ! we/]n coa/s ( ,irel& & ,engl&4 ,x !n goes r\nd ,scotl&1 br+s high wat] to ,ab]de5 & ! opposite coa/s ( ,norway & ,d5m>k1 &1 cont9u+ its c\rse to ! s\?1 arrives at ! m\? ( ! ,?ames & fills ! *annels ( t riv] on ! morn+ ( ! ?ird day aft] leav+ ! ,ant>ctic ,ocean4 ,?us ! tides 9 our ports are ow+ to an impulse f ! wat]s ( ! ,ant>ctic seas rais$ by ! action ( ! sun & moon4 ,no d\bt a simil> action rais$ t tide 9 ! ,nor? ,pol> ,ocean :i* ,dr4 ,kane saw roll+ on ! nor!rn coa/ ( ,gre5l& 9 #hb ,n4 latitude1 b :i*1 9 ! pres5t /ate ( ! globe1 is imprison$ by b>s ( ice & ice-b\nd l&s4 ,! tidal wave ext5ds to ! bottom ( ! ocean1 & moves uni=mly & ) great spe$ 9 v deep wat]1 v>iably & sl[ 9 %all[ wat]2 ! "t ( propagation dep5ds ^u ! dep? ( ! sea1 z well z on ! nature & =m ( ! coa/s4 ,x v>ies inv]sely z ! squ>e ( ! dep?--a law :i* !oretically af=ds ! means ( asc]ta9+ ! proportionate dep? ( ! sea 9 diff]5t p>ts4 ,x is "o ( ! great con/ants ( nature1 & is to fluids :at ! p5dulum is to solids--a connect+ l9k betwe5 "t & =ce4 ,= example3 ! tidal wave moves across ! ,s\!rn ,ocean ) ! velocity ( #ajjj miles an h\r1 & 9 ! ,atlantic x is sc>cely less on acc\nt ( ! deep tr\gh :i* runs ?r\gh ! c5tre ( t ocean2 b ! sea is s %all[ on ! ,briti% coa/ t x takes m "t to come f ,ab]de5 to ,london ?an to travel ov] an arc ( #abj1 betwe5 #fj ,s4 lat4 & #fj ,n4 lat4 ,9 deep wat] ! tidal wave is m]ely a rise & fall ( ! surface2 ! wat] does n advance1 ?\gh ! wave does4 ,inde$1 if s heavy a body z wat] 7 to move at ! rate ( #ajjj miles an h\r1 x w\ld cause univ]sal de/ruction1 s9ce 9 ! mo/ viol5t hurricanes ! velocity ( ! w9d is little m ?an #ajj miles an h\r4 ,besides1 x is evid5t t no %ip c\ld ei!r sail or /eam aga9/ x4 ,:5 ! wat] is %all[1 h[ev]1 !re is a motion ( translation 9 ! wat] along ) ! tide4 ,9 ! deep ocean ! undulat+ motion consi/s ( two di/9ct ?+s--an advanc+ =m & a molecul> movem5t4 ,! motion ( ea* p>ticle ( wat] is 9 an ellipse ly+ :olly 9 ! v]tical plane2 s t1 aft] ! mom5t>y displacem5t dur+ ! passage ( ! wave1 !y return to _! places aga94 ,! resi/ance ( ! sea-b$ is ins5sible 9 deep wat]2 b :5 ! tidal wave1 :i* ext5ds to ! v bottom ( ! ocean1 comes into %all[ wat] ) dim9i%$ velocity1 ! p>ticles ( wat] mov+ 9 v]tical ellipses /rike ! bottom1 & by reaction ! wave rises high]2 & t be+ cont9ually repeat$1 z ! =m moves on ! wave rises high] & high]1 b5ds m & m =w>d1 till at la/ x loses its equilibrium1 & !n bo? =m & wat] roll to ! %ore1 & ! elliptical trajectories ( ! p>ticles1 :i* 9 deep wat] 7 v]tical1 incl9e m & m1 till at l5g? !y become horizontal4 ,! di/ance f ! %ore at :i* ! wat] beg9s to be translat$ dep5ds ^u ! dep?1 ! nature ( ! coa/1 & ! =m ( ! %ore4 ,mr4 ,scott ,russell has demon/rat$ t 9 %all[ wat] ! velocity ( ! wave is equal to t :i* a heavy body fall+ freely by its gravity w\ld acquire 9 desc5d+ ?r\gh half ! dep? ( ! fluid4 ,x is prov$ by daily exp]i5ce1 z well z by /rict ma!matical reason+1 t1 if a numb] ( waves or oscillations be excit$ 9 a fluid by diff]5t =ces1 ea* pursues its c\rse & has its effect indep5d5tly ( ! re/4 ,n[1 9 ! tides !re are ?ree k9ds ( oscillations1 dep5d+ on diff]5t causes1 & produc+ _! effects indep5d5tly ( ea* o!r1 :i* may !re=e be e/imat$ sep>ately4 ,! oscillations ( ! fir/ k9d1 :i* are v small1 are indep5d5t ( ! rotation ( ! e>?1 &1 z !y dep5d ^u ! motion ( ! di/urb+ body 9 its orbit1 !y are ( long p]iods4 ,! second k9d ( oscillations dep5d ^u ! rotation ( ! e>?1 !re=e _! p]iod is ne>ly a day4 ,! oscillations ( ! ?ird k9d v>y ) an angle equal to twice ! angul> rotation ( ! e>?1 & consequ5tly happ5 twice 9 tw5ty-f\r h\rs 7,n4 #aeg74 ,! fir/ af=d no p>ticul> int]e/1 & are extremely small2 b ! diff]5ce ( two consecutive tides dep5ds ^u ! second4 ,at ! "t ( ! sol/ices ?is diff]5ce1 :i* ought to be v great accord+ to ,newton's !ory1 is h>dly s5sible on our %ores4 ,la ,place has %[n t ! discrepancy arises f ! dep? ( ! sea1 & t if ! dep? 7 uni=m !re w\ld be no diff]5ce 9 ! consecutive tides b t :i* is occasion$ by local circum/ances4 ,x foll[s1 !re=e1 t1 z ?is diff]5ce is extremely small1 ! sea1 consid]$ 9 a l>ge ext5t1 mu/ be ne>ly ( uni=m dep?1 t is to say1 !re is a c]ta9 mean dep? f :i* ! deviation is n great4 ,! mean dep? ( ! ,pacific ,ocean is suppos$ to be ab\t f\r or five miles1 t ( ! ,atlantic only ?ree or f\r1 :i*1 h[ev]1 is m]e conjecture4 ,possibly ! great ext5t & uni=mly small dep? ( ! ,atlantic ov] ! telegraphic plat=m may prev5t ! diff]5ce ( ! oscillations 9 "q f be+ p]ceptible on our %ores4 ,f ! =mul :i* det]m9e ! diff]5ce ( ^! consecutive tides x is prov$ t ! precession ( ! equ9oxes & ! nutation ( ! e>?'s axis are ! same z if ! sea =m$ "o solid mass ) ! e>?4 ,! oscillations ( ! ?ird k9d are ! semi-diurnal tides s rem>kable on our coa/s4 ,9 ^! !re are two ph5om5a p>ticul>ly to be di/+ui%$1 "o occurr+ twice 9 a mon?1 ! o!r twice 9 a ye>4 ,! fir/ ph5om5on is1 t ! tides are mu* increas$ 9 ! syzygies 7,n4 #aeh71 or at ! "t ( new & full moon3 9 bo? cases ! sun & moon are 9 ! same m]idian2 = :5 ! moon is new !y are 9 conjunction1 & :5 %e is full !y are 9 opposition4 ,9 ea* ( ^! positions _! action is comb9$ to produce ! highe/ or spr+ tides "u t m]idian1 & ! l[e/ 9 ^? po9ts t are #ij di/ant4 ,x is obs]v$ t ! high] ! sea rises 9 full tide1 ! l[] x is 9 ! ebb4 ,! neap tides take place :5 ! moon is 9 quadrature4 ,!y nei!r rise s high nor s9k s l[ z ! spr+ tides4 ,x is evid5t t ! spr+ tides mu/ happ5 twice 9 a mon?1 s9ce 9 t "t ! moon is once new & once full4 ,!ory proves t ea* p>tial tide increases z ! cube ( ! p>allax or app>5t diamet] ( ! body produc+ x1 = ! great] ! app>5t diamet] ! ne>] ! body & ! m int5se its action ^u ! sea2 h5ce ! spr+ tides are mu* increas$ :5 ! moon is 9 p]igee1 = !n %e is ne>e/ to ! e>?4 ,! second ph5om5on 9 ! tides is ! augm5tation occurr+ at ! "t ( ! equ9oxes1 :5 ! sun's decl9ation is z]o 7,n4 #aei71 :i* happ5s twice 9 e ye>4 ,! spr+ tides :i* take place at t "t are (t5 mu* increas$ by ! equ9octial gales1 &1 on ! hypo!sis ( ! :ole e>? cov]$ by ! ocean1 w\ld be ! greate/ possible if ! l9e ( ! moon's nodes co9cid$ ) t ( h] p]igee1 = !n ! :ole action ( ! lum9>ies w\ld be 9 ! plane ( ! equator4 ,b s9ce ! ,ant>ctic ,ocean is ! s\rce ( ! tides1 x is evid5t t ! spr+ tide mu/ be greate/ :5 ! moon is 9 p]igee1 & :5 bo? lum9>ies h _! highe/ s\!rn decl9ation1 = !n !y act mo/ directly ^u ! great circuit ( ! s\? pol> seas4 ,! sun & moon are cont9ually mak+ ! circuit ( ! heav5s at diff]5t di/ances f ! plane ( ! equator1 on acc\nt ( ! obliquity ( ! ecliptic & ! incl9ation ( ! lun> orbit4 ,! moon takes ab\t #bi-a_/b days to v>y ?r\gh all h] decl9ations1 :i* sometimes ext5d #bh-c_/d on ea* side ( ! equator1 :ile ! sun requires ne>ly #cfe-a_/d days to accompli% 8 motions ?r\gh #bc-a_/b on ea* side ( ! same plane1 s t _! comb9$ action causes great v>iations 9 ! tides4 ,bo? ! height & "t ( high wat] are p]petually *ang+1 &1 al?\gh ! problem does n admit ( a g5]al solution1 x is necess>y to analyse ! ph5om5a :i* ought to arise f ! attraction ( ! sun & moon1 b ! result mu/ be correct$ 9 ea* p>ticul> case = local circum/ances1 s t ! !ory ( ! tides 9 ea* port becomes really a matt] ( exp]im5t1 & c only be det]m9$ by means ( a va/ numb] ( obs]vations1 includ+ _m revolutions ( ! moon's nodes4 ,! mean height ( ! tides w be increas$ by a v small quantity = ages to come1 9 consequ5ce ( ! decrease 9 ! mean di/ance ( ! moon f ! e>?2 ! contr>y effect w take place aft] t p]iod has elaps$1 & ! moon's mean di/ance beg9s to increase aga91 :i* x w cont9ue to d = _m ages4 ,?us ! mean di/ance ( ! moon & ! consequ5t m9ute increase 9 ! height ( ! tides w oscillate betwe5 fix$ limits = ev]4 ,! height to :i* ! tides rise is mu* great] 9 n>r[ *annels ?an 9 ! op5 sea1 on acc\nt ( ! ob/ructions !y meet )4 ,! sea is s p5t up 9 ! ,briti% ,*annel t ! tides sometimes rise z mu* z fifty feet at ,/4 ,malo1 on ! coa/ ( ,france2 :]eas on ! %ores ( "s ( ! ,s\? ,sea isl&s1 ne> ! c5tre ( ! ,pacific1 !y d n exce$ "o or two feet4 ,! w9ds h great influ5ce on ! height ( ! tides1 accord+ z !y conspire ) or oppose !m4 ,b ! actual effect ( ! w9d 9 excit+ ! waves ( ! ocean ext5ds v little bel[ ! surface4 ,ev5 9 ! mo/ viol5t /orms ! wat] is probably calm at ! dep? ( n9ety or a hundr$ fa?oms4 ,! tidal wave ( ! ocean does n rea* ! ,m$it]ranean nor ! ,baltic1 p>tly f _! position & p>tly f ! n>r[ness ( ! ,/raits ( ,gibralt> & ( ! ,categat1 b x is v p]ceptible 9 ! ,r$ ,sea & 9 ,hudson's ,bay4 ,! ebb & fl[ ( ! sea are p]ceptible 9 riv]s to a v great di/ance f _! e/u>ies4 ,9 ! ,n>r[s ( ,pauxis1 9 ! riv] ( ! ,amazons1 m ?an five hundr$ miles f ! sea1 ! tides are evid5t4 ,x requires s _m days = ! tide to asc5d ?is mighty /ream1 t ! return+ tides meet a succession ( ^? :i* are com+ up2 s t e possible v>iety occurs at "s "p or o!r ( its %ores1 bo? z to magnitude & "t4 ,x requires a v wide expanse ( wat] to accumulate ! impulse ( ! sun & moon1 s z to r5d] _! influ5ce s5sible2 on t acc\nt ! tides 9 ! ,m$it]ranean & ,black ,sea are sc>cely p]ceptible4 ,^! p]petual commotions 9 ! wat]s are occasion$ by =ces t be> a v small proportion to t]re/rial gravitation3 ! sun's action 9 rais+ ! ocean is only ! #a_/chddhjjj ( gravitation at ! e>?'s surface1 & ! action ( ! moon is little m ?an twice z mu*2 ^! =ces be+ 9 ! ratio ( #a to #b4ceccc1 :5 ! sun & moon are at _! mean di/ances f ! e>?4 ,f ?is ratio ! mass ( ! moon is f\nd to be only ! #a_/ge "p ( t ( ! e>?4 ,_h ! action ( ! sun on ! ocean be5 exactly equal to t ( ! moon1 !re w\ld h be5 no neap tides1 & ! spr+ tides w\ld h be5 ( twice ! height :i* ! action ( ei!r ! sun or moon w\ld h produc$ sep>ately--a ph5om5on dep5d+ ^u ! int]f]5ce ( ! waves or undulations4 ,a /one plung$ into a pool ( /ill wat] occasions a s]ies ( waves to advance along ! surface1 ?\gh ! wat] itself is n c>ri$ =w>d1 b only rises into heights & s9ks into holl[s1 ea* portion ( ! surface be+ elevat$ & depress$ 9 its turn4 ,ano!r /one ( ! same size1 ?r[n into ! wat] ne> ! fir/1 w occasion a simil> set ( undulations4 ,!n1 if an equal & simil> wave f ea* /one arrive at ! same spot at ! same "t1 s t ! elevation ( ! "o exactly co9cides ) ! elevation ( ! o!r1 _! unit$ effect w produce a wave twice ! size ( ei!r4 ,b1 if "o wave prec$e ! o!r by exactly half an undulation1 ! elevation ( ! "o w co9cide ) ! holl[ ( ! o!r1 & ! holl[ ( ! "o ) ! elevation ( ! o!r2 & ! waves w s entirely oblit]ate "o ano!r1 t ! surface ( ! wat] w rema9 smoo? & level4 ,h5ce1 if ! l5g? ( ea* wave be repres5t$ by #a1 !y w de/roy "o ano!r at int]vals ( #a_/b1 #c_/b1 #e_/b1 c41 & w comb9e _! effects at ! int]vals #a1 #b1 #c1 c4 ,x w be f\nd accord+ to ?is pr9ciple1 :5 /ill wat] is di/urb$ by ! fall ( two equal /ones1 t !re are c]ta9 l9es on its surface ( a hyp]bolic =m1 :]e ! wat] is smoo? 9 consequ5ce ( ! waves oblit]at+ ea* o!r1 & t ! elevation ( ! wat] 9 ! adjac5t p>ts corresponds to bo? ! waves unit$ 7,n4 #afj74 ,n[1 9 ! spr+ & neap tides aris+ f ! comb9ation ( ! simple solilun> waves1 ! spr+ tide is ! jo9t result ( ! comb9ation :5 !y co9cide 9 "t & place2 & ! neap tide happ5s :5 !y succe$ ea* o!r by half an int]val1 s z to leave only ! effect ( _! diff]5ce s5sible4 ,x is1 !re=e1 evid5t t1 if ! sol> & lun> tides 7 ( ! same height1 !re w\ld be no diff]5ce1 consequ5tly no neap tides1 & ! spr+ tides w\ld be twice z high z ei!r sep>ately4 ,9 ! port ( ,bat%a1 9 ,tonqu91 :]e ! tides arrive by two *annels ( l5g?s correspond+ to half an int]val1 !re is nei!r high nor l[ wat] on acc\nt ( ! int]f]5ce ( ! waves4 ,! initial /ate ( ! ocean has no influ5ce on ! tides2 =1 :atev] its primitive conditions may h be51 !y mu/ soon h vani%$ by ! friction & mobility ( ! fluid4 ,"o ( ! mo/ rem>kable circum/ances 9 ! !ory ( ! tides is ! assurance t1 9 consequ5ce ( ! d5sity ( ! sea be+ only "o-fif? ( ! mean d5sity ( ! e>?1 & ! e>? itself increas+ 9 d5sity t[>ds ! c5tre1 ! /ability ( ! equilibrium ( ! ocean nev] c be subv]t$ by any physical cause4 ,a g5]al inundation aris+ f ! m]e in/ability ( ! ocean is !re=e impossible4 ,a v>iety ( circum/ances1 h[ev]1 t5d to produce p>tial v>iations 9 ! equilibrium ( ! seas1 :i* is re/or$ by means ( curr5ts4 ,w9ds & ! p]iodical melt+ ( ! ice at ! poles occasion tempor>y wat]c\rses2 b by f> ! mo/ important causes are ! c5trifugal =ce induc$ by ! velocity ( ! e>?'s rotation1 & v>iations 9 ! d5sity ( ! sea4 ,! c5trifugal =ce may be resolv$ into two =ces--"o p]p5dicul>1 & ano!r tang5t to ! e>?'s surface 7,n4 #afa74 ,! tang5tial =ce1 ?\gh small1 is suffici5t to make ! fluid p>ticles )9 ! pol> circles t5d t[>ds ! equator1 & ! t5d5cy is mu* increas$ by ! imm5se evaporation 9 ! equatorial regions f ! heat ( ! sun1 :i* di/urbs ! equilibrium ( ! ocean4 ,to ?is may also be add$ ! sup]ior d5sity ( ! wat]s ne> ! poles1 f _! l[ temp]ature4 ,9 consequ5ce ( ! comb9ation ( all ^! circum/ances1 two great curr5ts p]petually set f ea* pole t[>ds ! equator4 ,b1 z !y come f latitudes :]e ! rotatory motion ( ! surface ( ! e>? is v mu* less ?an x is betwe5 ! tropics1 on acc\nt ( _! in]tia1 !y d n imm$iately acquire ! velocity ) :i* ! solid "p ( ! e>?'s surface is revolv+ at ! equatorial regions2 f :5ce x foll[s t1 )9 tw5ty-five or ?irty degrees on ea* side ( ! l9e1 ! ocean has a g5]al motion f ea/ to we/1 :i* is mu* increas$ by ! action ( ! trade w9ds4 ,bo? 9 ! ,pacific & ,atlantic curr5ts ( enorm\s magnitude are deflect$ by ! cont95ts & isl&s to ! nor? & s\? f ?is mighty mass ( ru%+ wat]s1 :i* convey ! w>m? ( ! equator to temp] ! sev]ity ( ! pol> regions1 :ile to ma9ta9 ! equilibrium ( ! seas c\nt] curr5ts ( cold wat] are p\r$ f ! pol> oceans to m+le ) ! w>m wat]s at ! l9e1 s t a p]petual circulation is ma9ta9$4 ,iceb]gs are sometimes drift$ z f> z ! ,azores f ! ,pol> seas1 & f ! s\? pole !y h come ev5 to ! ,cape ( ,good ,hope4 ,b ! ice :i* encircles ! s\? pole ext5ds to l[] latitudes by #aj ?an t :i* surr\nds ! nor?4 ,9 consequ5ce ( ! pol> curr5t ,sir ,edw>d ,p>ry 0 oblig$ to give up 8 attempt to rea* ! nor? pole 9 ! ye> #ahbg1 because ! fields ( ice 7 drift+ to ! s\? fa/] ?an 8 p>ty c\ld travel ov] !m to ! nor?4 ,kotzebue & ,sir ,james ,ross f\nd a /ratum ( con/ant temp]ature 9 ! ocean at a dep? dep5d+ ^u ! latitude3 at ! equator x is at ! dep? ( #gbjj feet1 f :5ce x gradually rises till x comes to ! surface 9 bo? hemisph]es ab\t ! latitude ( #ef #bf1 :]e ! wat] has ! same temp]ature at all dep?s2 x !n desc5ds to #dejj feet bel[ ! surface ab\t ! #gj? p>allel bo? 9 ! ,arctic & ,ant>ctic ,seas4 ,! temp]ature ( t aque\s zone is ab\t #cie ( ,fahr5heit4#g ,x divides ! surface ( ! ocean into five great zones ( temp]ature1 namely1 a m$ial region1 9 :i* ! highe/ mean temp]ature is #hb ,fahr41 two temp]ate zones ea* ( #cie ,fahr41 & two pol> bas9s at ! freez+ po9t ( salt wat]4 ,,section ,,xiv4 ,molecul> ,=ces--,p]man5cy ( ! ultimate ,p>ticles ( ,matt]--,int]/ices--,mossotti's ,!ory--,rank9's ,!ory ( ,molecul> ,vortices--,gases r$uc$ to ,liquids by ,pressure--,gravitation ( ,p>ticles--,cohesion--,cry/allization--, cleavage--,isomorphism--,m9ut5ess ( ! ,p>ticles--,height ( ,atmosph]e--,*emical ,aff9ity--,def9ite ,proportions & ,relative ,weights ( ,atoms--,f>aday's ,discov]y ) reg>d to ,aff9ity--,capill>y ,attraction4 ,,! oscillations ( ! atmosph]e1 & its action ^u ! rays ( light com+ f ! heav5ly bodies1 connect ! sci5ce ( a/ronomy ) ! equilibrium & movem5ts ( fluids & ! laws ( molecul> attraction4 ,hi!rto t =ce has be5 "u consid]ation :i* acts ^u masses ( matt] at s5sible di/ances2 b n[ ! effects ( su* =ces are to be consid]$ z act at inappreciable di/ances ^u ! ultimate molecules ( mat]ial bodies4 ,all sub/ances consi/ ( an assemblage ( mat]ial p>ticles1 or molecules1 :i* are f> too small to be visible by any means human +5uity has yet be5 able to devise1 & :i* are mu* beyond ! limits ( our p]ceptions4 ,!y nei!r c be creat$ nor de/roy$2 bodies may be burn$1 b _! p>ticles are n consum$--!y are m]ely lib]at$ f "o comb9ation to ent] into ano!r1 nor are _! peculi> prop]ties ev] *ang$2 :atev] comb9ations !y may ent] into1 !y are ev] & inv>iably ! same4 ,s9ce e kn[n sub/ance may be r$uc$ 9 bulk by pressure1 x foll[s t ! p>ticles ( matt] are n 9 actual contact1 b are sep>at$ by int]/ices2 & x is evid5t t ! small] ! int]/itial spaces ! great] ! d5sity4 ,^! spaces appe> to be fill$ ) air 9 "s cases1 z may be inf]r$ f c]ta9 semi-opaque m9]als & o!r sub/ances becom+ transp>5t :5 plung$ into wat]4 ,sometimes !y may possibly conta9 "s unkn[n & highly ela/ic fluid1 su* z ,sir ,david ,brew/] has discov]$ 9 ! m9ute cavities ( v>i\s m9]als1 :i* occasionally causes !m to explode "u ! h&s ( ! lapid>y2 b z x is inconceivable t ! p>ticles ( matt] %\ld act ^u "o ano!r )\t "s means ( communication1 x is presum$ t ! int]/ices ( mat]ial sub/ances conta9 a portion ( ! e!real m$ium ) :i* ! regions ( space are fill$4 ,! v>i\s hypo!ses t h be5 =m$ z to ! nature & action ( ! =ces :i* unite ! p>ticles ( matt]1 h be5 successively giv5 up z sci5ce advanc$1 & n[ no?+ decisive has be5 atta9$1 al?\gh ,pr(essor ,mossotti1 ( ,pisa1 by a v able analysis1 has endeav\r$ to prove ! id5tity ( ! cohesive =ce ) gravitation4 ,z ! p>ticles ( mat]ial bodies are n 9 actual contact1 he supposes t ea* is surr\nd$ by an atmosph]e ( ! e!real m$ium1 :i* he conceives to be electricity2 moreov] he assumes t ! atoms ( ! m$ium repel "o ano!r1 t ! p>ticles ( matt] also repel "o ano!r1 b ) less int5sity1 & t !re is a mutual attraction betwe5 ! p>ticles ( matt] & ! atoms ( ! m$ium1 =ces :i* are assum$ to v>y inv]sely z ! squ>e ( ! di/ance4 ,h5ce1 :5 ! mat]ial molecules ( a body are inappreciably ne> to "o ano!r1 !y mutually repel ea* o!r ) a =ce :i* dim9i%es rapidly z ! inf9itely small di/ance betwe5 ! mat]ial molecules augm5ts1 & at la/ vani%es4 ,:5 ! molecules are /ill f>!r ap>t1 ! =ce becomes attractive4 ,at t p>ticul> po9t :]e ! *ange takes place ! =ces ( repulsion & attraction balance ea* o!r1 s t ! molecules ( a body are nei!r dispos$ to approa* nor rec$e1 b rema9 9 equilibrio4 ,if we try to press !m ne>]1 ! repulsive =ce resi/s ! attempt2 & if we endeav\r to break ! body s z to te> ! p>ticles asund]1 ! attractive =ce pr$om9ates & keeps !m toge!r4 ,?is is :at con/itutes ! cohesive =ce1 or =ce ( aggregation1 by :i* ! molecules ( all sub/ances are unit$4 ,! limits ( ! di/ance at :i* ! negative action becomes positive v>y accord+ to ! temp]ature & nature ( ! molecules1 & det]m9e :e!r ! body :i* !y =m be solid1 liquid1 or ari=m4 ,beyond ?is neutral po9t ! attractive =ce increases z ! di/ance betwe5 ! molecules augm5ts till x atta9s a maximum2 :5 ! p>ticles are m ap>t1 x dim9i%es2 &1 z soon z !y are sep>at$ by f9ite or s5sible di/ances1 x v>ies directly z _! mass & inv]sely z ! squ>e ( ! di/ance1 :i* is precisely ! law ( univ]sal gravitation4 ,?us1 on ! hypo!sis t ! mutual repulsion betwe5 ! electric atoms is a little m p[]ful ?an ! mutual repulsion betwe5 ! p>ticles ( matt]1 ! e!r & ! matt] attract ea* o!r ) unequal int5sities1 :i* leaves an excess ( attractive =ce con/itut+ gravitation4 ,z ! gravitat+ =ce is 9 op]ation :]ev] !re is matt]1 ! e!real electric m$ium mu/ encompass all ! bodies 9 ! univ]se2 &1 z x is utt]ly incompreh5sible t ! cele/ial bodies %\ld ex]t a reciprocal attraction ?r\gh a void1 ! ,pr(essor concludes t ! e!real electrical m$ium fills all space4 ,x is true t ?is connexion betwe5 ! molecul> =ces & gravitation dep5ds ^u hypo!sis2 b 9 ! great] numb] ( physical inve/igations "s hypo!sis is requisite 9 ! fir/ in/ance to aid ! imp]fection ( our s5ses2 & :5 ! ph5om5a ( nature accord ) ! assumption1 we are ju/ifi$ 9 believ+ x to be a g5]al law4 ,mr4 ,rank9's !ory ( molecul> vortices1 or ! molecul> /ructure ( matt]1 is indep5d5t ( electricity4 ,accord+ to 8 hypo!sis1 ea* atom ( matt] consi/s ( an inappreciably small nucleus1 encompass$ by an ela/ic e!real atmosph]e :i* is reta9$ 9 its position by attractive =ces direct$ t[>ds ! molecule1 :il/ ! molecules attract ea* o!r 9 ! direction ( /raight l9es jo9+ _! c5tres4 ,! nuclei may ei!r be solid1 or a high cond5sation ( ! atmosph]es :i* surr\nd ea* ) decreas+ d5sity4 ,:5 ! attraction betwe5 ! molecules is su* t ! ela/icity ( ! atmosph]es is ins5sible1 ! body is a p]fect solid1 ! rigidity ( :i* be>s a c]ta9 def9ite proportion to ! ela/icity ( ! volume4 ,:5 ! atmosph]es are less cond5s$ & ! attraction ( ! molecules m]ely produces a cohesive =ce suffici5t to balance ! atomic ela/icity ( ! atmosph]e1 ! body is a p]fect liquid2 & :5 ! attraction ( ! molecules is v small comp>$ ) ! ela/icity ( _! e!real atmosph]es1 ! body is a p]fect gas4 ,^! atmosph]es are suppos$ to be portions ( ! e!real m$ium :i* p5etrates into ! int]/ices ( e sub/ance1 & _! ela/icity to be due to ! heat g5]at$ by ! c5trifugal =ce or oscillations among _! atoms1 = motion is ! cause ( heat1 ! =ce produc+ ! motions v>y+ simply z ! d5sity ( ! e!r4 ,9 ari=m fluids1 al?\gh ! p>ticles are m remote f ea* o!r ?an 9 liquids & solids1 yet ! pressure may be s great z to r$uce an ari=m fluid to a liquid1 & a liquid to a solid4 ,dr4 ,f>aday has r$uc$ "s ( ! gases to a liquid /ate by v great compression2 b al?\gh atmosph]ic air is capable ( a dim9ution ( volume to :i* we d n "k a limit1 x has hi!rto always reta9$ its gase\s qualities1 & resumes its primitive volume ! in/ant ! pressure is remov$4 ,sub/ances are said to be m or less ela/ic1 accord+ to ! facility ) :i* !y rega9 _! bulk or volume :5 ! pressure is remov$2 ?us liquids resi/ compression on acc\nt ( _! ela/icity1 & 9 solids ! resi/ance is mu* great] b v>iable1 & ! ef=t requir$ to break a sub/ance is a measure ( ! cohesive =ce ex]t$ by its p>ticles4 ,9 /one1 iron1 /eel1 & all brittle & h>d sub/ances1 ! cohesion ( ! p>ticles is p[]ful b ( small ext5t2 9 ela/ic bodies1 on ! contr>y1 its action is weak1 b m ext5sive4 ,an inf9ite v>iety ( conditions may be obs]v$ 9 ! fusion ( metals & o!r sub/ances pass+ f h>dness to t\ghness1 viscidity1 & ?r\gh all ! o!r /ages to p]fect fluidity & ev5 to vap\r4 ,s9ce all bodies exp& by heat1 ! cohesive =ce is weak5$ by increase ( temp]ature4 ,! cohesion ( matt] or ! /r5g? ( sub/ances =ms an important bran* ( /udy 9 eng9e]+4 ,e p>ticle ( matt]1 :e!r x =ms a con/itu5t "p ( a solid1 liquid1 or ari=m fluid1 is subject to ! law ( gravitation4 ,! weight ( ! atmosph]e1 ( gases & vap\r1 %[s t !y consi/ ( gravitat+ p>ticles4 ,9 liquids ! cohesive =ce is n suffici5tly p[]ful to resi/ ! action ( gravitation4 ,!re=e1 al?\gh _! compon5t p>ticles /ill ma9ta9 _! connexion1 ! liquid is scatt]$ by _! weight1 unless :5 x is conf9$ 9 a vessel or has already desc5d$ to ! l[e/ po9t possible1 & assum$ a level surface f ! mobility ( its p>ticles & ! influ5ce ( ! gravitat+ =ces1 z 9 ! ocean1 or a lake4 ,solids w\ld also fall to pieces by ! weight ( _! p>ticles1 if ! =ce ( cohesion 7 n p[]ful en\gh to resi/ ! ef=ts ( gravitation4 ,! ph5om5a aris+ f ! =ce ( cohesion are innum]able4 ,! sph]ical =m ( ra9-drops2 ! difficulty ( deta*+ a plate ( glass f ! surface ( wat]2 ! =ce ) :i* two plane surfaces adh]e :5 press$ toge!r2 ! drops t cl+ to ! w9d[-glass 9 a %[] ( ra9--are all effects ( cohesion entirely indep5d5t ( atmosph]ic pressure1 & are includ$ 9 ! same analytical =mula 7,n4 #afb7 :i* expresses all ! circum/ances accurately1 al?\gh ! laws accord+ to :i* ! =ces ( cohesion & repulsion v>y are unkn[n4 ,x is m ?an probable t ! sph]ical =m ( ! sun & planets is due to ! =ce ( cohesion1 z !y h e appe>ance ( hav+ be5 at "o p]iod 9 a /ate ( fusion4 ,a v rem>kable in/ance has occasionally be5 obs]v$ 9 plate-glass manufactories4 ,aft] ! l>ge plates ( glass ( :i* mirrors are to be made h receiv$ _! la/ poli%1 !y are c>efully wip$ & laid on _! edges ) _! surfaces re/+ on "o ano!r4 ,9 ! c\rse ( "t ! cohesion has sometimes be5 s p[]ful1 t !y c\ld n be sep>at$ )\t break+4 ,in/ances h occurr$ :]e two or ?ree h be5 s p]fectly unit$1 t !y h be5 cut & _! edges poli%$ z if !y _h be5 fus$ toge!r2 & s great 0 ! =ce requir$ to make ! surfaces slide t "o tore (f a portion ( ! surface ( ! o!r4 ,9 liquids & gases ! =ms ( ! p>ticles h no influ5ce1 !y are s f> ap>t2 b ! /ructure ( solids v>ies accord+ to ! sides :i* ! p>ticles pres5t to "o ano!r dur+ _! aggregation4 ,no?+ is kn[n ( _! =m fur!r ?an ! dissimil>ity ( _! diff]5t sides 9 c]ta9 cases1 :i* appe>s f _! reciprocal attractions dur+ cry/allisation be+ m or less p[]ful accord+ to ! sides !y pres5t to "o ano!r4 ,cry/allisation is an effect ( molecul> attraction regulat$ by c]ta9 laws1 accord+ to :i* atoms ( ! same k9d ( matt] unite 9 regul> =ms--a fact easily prov$ by dissolv+ a piece ( alum 9 pure wat]4 ,! mutual attraction ( ! p>ticles is de/roy$ by ! wat]2 b1 if x be evaporat$1 !y unite1 & =m 9 unit+ eight-sid$ figures call$ octah$rons 7,n4 #afc74 ,^! h[ev] are n all ! same4 ,"s h _! angles cut (f1 o!rs _! edges1 & "s bo?1 :ile ! rema9d] take ! regul> =m4 ,x is q cle> t ! same circum/ances :i* cause ! aggregation ( a few p>ticles w\ld1 if cont9u$1 cause ! addition ( m2 & ! process w\ld g on z long z any p>ticles rema9 free r\nd ! primitive nucleus1 :i* w\ld increase 9 size1 b w\ld rema9 un*ang$ 9 =m1 ! figure ( ! p>ticles be+ su* z to ma9ta9 ! regul>ity & smoo?ness ( ! surfaces ( ! solid & _! mutual incl9ations4 ,a brok5 cry/al w by degrees resume its regul> figure :5 put back aga9 into ! solution ( alum1 :i* %[s t ! int]nal & ext]nal p>ticles are simil>1 & h a simil> attraction = ! p>ticles held 9 solution4 ,! orig9al conditions ( aggregation :i* make ! molecules ( ! same sub/ance unite 9 diff]5t =ms mu/ be v num]\s1 s9ce ( c>bonate ( lime alone !re are _m hundr$ v>ieties2 & c]ta9 x is1 f ! motion ( pol>is$ light ?r\gh rock cry/al1 t a v diff]5t arrangem5t ( p>ticles is requisite to produce an extremely small *ange 9 ext]nal =m4 ,a v>iety ( sub/ances 9 cry/allis+ comb9e *emically ) a c]ta9 portion ( wat] :i* 9 a dry /ate =ms an ess5tial "p ( _! cry/als1 &1 accord+ to ! exp]im5ts ( ,,mm4 ,haid+] & ,mits*]li*1 seems 9 "s cases to give ! peculi> det]m9ation to _! con/itu5t molecules4 ,^! g5tlem5 h obs]v$ t ! same sub/ance cry/allis+ at diff]5t temp]atures unites ) diff]5t quantities ( wat] & assumes a correspond+ v>iety ( =ms4 ,sel5iate ( z9c1 = example1 unites ) ?ree diff]5t portions ( wat]1 & assumes ?ree diff]5t =ms1 accord+ z its temp]ature 9 ! act ( cry/allis+ is hot1 lukew>m1 or cold4 ,sulphate ( soda also1 :i* cry/allises at #ij ( ,fahr5heit )\t wat] ( cry/allisation1 comb9es ) wat] at ! ord9>y temp]ature1 & takes a diff]5t =m4 ,heat appe>s to h a great influ5ce on ! ph5om5a ( cry/allisation1 n only :5 ! p>ticles ( matt] are free1 b ev5 :5 firmly unit$1 = x dissolves _! union1 & gives !m ano!r det]m9ation4 ,pr(essor ,mits*]li* f\nd t prismatic cry/als ( sulphate ( nickel 7,n4 #afd71 expos$ to a summ]'s sun 9 a close vessel1 _h _! int]nal /ructure s completely alt]$ )\t any ext]ior *ange1 t :5 brok5 op5 !y 7 compos$ int]nally ( octah$rons ) squ>e bases4 ,! orig9al aggregation ( ! int]nal p>ticles _h be5 dissolv$1 & a disposition giv5 to arrange !mselves 9 a cry/all9e =m4 ,cry/als ( sulphate ( magnesia & ( sulphate ( z9c1 gradually heat$ 9 alcohol till x boils1 lose _! transp>5cy by degrees1 & :5 op5$ are f\nd to consi/ ( innum]able m9ute cry/als totally diff]5t 9 =m f ! :ole cry/als2 & prismatic cry/als ( z9c 7,n4 #afe7 are *ang$ 9 a few seconds into octah$rons by ! heat ( ! sun3 o!r in/ances might be giv5 ( ! influ5ce ( ev5 mod]ate degrees ( temp]ature on molecul> attraction 9 ! int]ior ( sub/ances4 ,x mu/ be obs]v$ t ^! exp]im5ts give entirely new views ) reg>d to ! con/itution ( solid bodies4 ,we are l$ f ! mobility ( fluids to expect great *anges 9 ! relative positions ( _! molecules1 :i* mu/ be 9 p]petual motion ev5 9 ! /ille/ wat] or calme/ air2 b we 7 n prep>$ to f9d motion to su* an ext5t 9 ! int]ior ( solids4 ,t _! p>ticles are br\ght ne>] by cold & pressure1 or remov$ f>!r f "o ano!r by heat1 might be expect$2 b x c\ld n h be5 anticipat$ t _! relative positions c\ld be s entirely *ang$ z to alt] _! mode ( aggregation4 ,x foll[s1 f ! l[ temp]ature at :i* ^! *anges are effect$1 t !re is probably no portion ( inorganic matt] t is n 9 a /ate ( relative motion4 ,pr(essor ,mits*]li*'s discov]ies ) reg>d to ! =ms ( cry/allis$ sub/ances1 z connect$ ) _! *emical "*1 h ?r[n additional light on ! con/itution ( mat]ial bodies4 ,!re is a c]ta9 set ( cry/all9e =ms :i* are n susceptible ( v>iation1 z ! die or cube 7,n4 #aff71 :i* may be small or l>ge1 b is inv>iably a solid b\nd$ by six squ>e surfaces or planes4 ,su* also is ! tetrah$ron 7,n4 #afg7 or f\r-sid$ solid conta9$ by f\r equal-sid$ triangles4 ,sev]al o!r solids belong to ?is class1 :i* is call$ ! ,tessul> sy/em ( cry/allisation4 ,!re are o!r cry/als :i*1 ?\gh b\nd$ by ! same numb] ( sides1 & hav+ ! same =m1 are yet susceptible ( v>iation2 = in/ance1 ! eight-sid$ figure ) a squ>e base1 call$ an octah$ron 7,n4 #afh71 :i* is sometimes flat & l[1 & sometimes acute & high4 ,x 0 =m]ly believ$ t id5tity ( =m 9 all cry/als n belong+ to ! ,tessul> sy/em indicat$ id5tity ( *emical composition4 ,pr(essor ,mits*]li*1 h[ev]1 has %[n t sub/ances diff]+ to a c]ta9 degree 9 *emical composition h ! prop]ty ( assum+ ! same cry/all9e =m4 ,= example1 ! neutral phosphate ( soda & ! ars5iate ( soda cry/allise 9 ! v same =m1 conta9 ! same quantities ( acid1 alkali1 & wat] ( cry/allisation2 yet !y diff] s f>1 t "o conta9s ars5ic & ! o!r an equival5t quantity ( phosphorus4 ,sub/ances hav+ su* prop]ties are said to be isomorph\s1 t is1 equal 9 =m4 ,( ^! !re are _m gr\ps1 ea* gr\p hav+ ! same =m1 & simil>ity ?\gh n id5tity ( *emical composition4 ,= in/ance1 "o ( ! isomorph\s gr\ps is t consi/+ ( c]ta9 *emical sub/ances call$ ! protoxides ( iron1 copp]1 z9c1 nickel1 & manganese1 all ( :i* are id5tical 9 =m & conta9 ! same quantity ( oxyg51 b diff] 9 ! respective metals !y conta91 :i* are1 h[ev]1 ne>ly 9 ! same proportion 9 ea*4 ,all ^! circum/ances t5d to prove t sub/ances hav+ ! same cry/all9e =m mu/ consi/ ( ultimate atoms hav+ ! same figure & arrang$ 9 ! v same ord]2 s t ! =m ( cry/als is dep5d5t on _! atomic con/itution4 ,all cry/allis$ bodies h jo9ts call$ cleavages1 at :i* !y split m easily ?an 9 o!r directions2 on ?is prop]ty ! :ole art ( cutt+ diamonds dep5ds4 ,ea* sub/ance splits 9 a mann] & 9 =ms peculi> to itself4 ,= example1 all ! hundr$s ( =ms ( c>bonate ( lime split into six-sid$ figures1 call$ rhomboh$rons 7,n4 #afi71 ^: alt]nate angles measure #ajeee & #geje1 h[ev] f> ! division may be c>ri$2 !re=e ! ultimate p>ticle ( c>bonate ( lime is presum$ to h t =m4 ,h[ev] ?is may be1 x is c]ta9 t all ! v>i\s cry/als ( t m9]al may be =m$ by build+ up six-sid$ solids ( ! =m describ$1 9 ! same mann] z *ildr5 build h\ses ) m9iature bricks4 ,x may be imag9$ t a wide diff]5ce may exi/ betwe5 ! p>ticles ( an un=m$ mass & a cry/al ( ! same sub/ance--betwe5 ! common %apeless lime/one & ! pure & limpid cry/al ( ,icel& sp>2 yet *emical analysis detects none2 _! ultimate atoms are id5tical1 & cry/allisation %[s t ! diff]5ce arises only f ! mode ( aggregation4 ,besides1 all sub/ances ei!r cry/allise naturally1 or may be made to d s by art4 ,liquids cry/allise 9 freez+1 vap\rs by sublimation 7,n4 #agj72 & h>d bodies1 :5 fus$1 cry/allise 9 cool+4 ,h5ce x may be inf]r$ t all sub/ances are compos$ ( atoms1 on ^: magnitude1 d5sity1 & =m1 _! nature & qualities dep5d2 &1 z ^! qualities are un*angeable1 ! ultimate p>ticles ( matt] mu/ be incapable ( we>--! same n[ z :5 creat$4 ,! size ( ! ultimate p>ticles ( matt] mu/ be small 9 ! extreme4 ,organis$ be+s1 possess+ life & all its functions1 h be5 discov]$ s small1 t a million ( !m w\ld occupy less space ?an a gra9 ( s&4 ,! malleability ( gold1 ! p]fume ( musk1 ! od\r ( fl[]s1 & _m o!r in/ances might be giv5 ( ! excessive m9ut5ess ( ! atoms ( matt]4 ,suppos+ ! d5sity ( ! air at ! surface ( ! e>? to be repres5t$ by unity1 ,sir ,john ,h]s*el has %[n t1 "u any hypo!sis z to its atoms1 x w\ld require a fraction hav+ at lea/ #acgj figures 9 its d5om9ator to express its t5uity 9 ! int]planet>y space2 yet ! def9ite proportions ( *emical comp\nds af=d a pro( t divisibility ( matt] has a limit4 ,! cohesive =ce1 :i* has be5 ! subject ( ! prec$+ consid]ations1 only unites p>ticles ( ! same k9d ( matt]2 :]eas aff9ity1 :i* is ! cause ( *emical comp\nds1 is ! mutual attraction betwe5 p>ticles ( diff]5t k9ds ( matt]1 g5]ally produc+ a comp\nd :i* has no s5sible prop]ty 9 common ) its compon5t p>ts except t ( _! comb9$ gravity1 z1 = example1 wat]1 :i* is a comp\nd ( oxyg5 & hydrog5 gases4 ,x is m]ely a result ( ! electrical /ate ( ! p>ticles1 *emical aff9ity & electricity be+ only =ms ( ! same p[]4 ,9 mo/ cases x produces electricity1 z 9 ! oxidation ( metals & combu/ion1 & 9 e case )\t exception heat is evolv$ by bodies :ile comb9+ *emically2 & z heat is an expansive =ce1 *emical action is *ang$ into me*anical expansion1 b x is n kn[n 9 ?is case :y heat is produc$1 nor ! mann] 9 :i* ! p>ticles act4 ,x is a p]man5t & univ]sal law 9 va/ numb]s ( unorganis$ bodies t _! composition is def9ite & inv>iable1 ! same comp\nd always consi/+ ( ! same elem5ts unit$ toge!r 9 ! same proportions4 ,two sub/ances may inde$ be mix$2 b !y w n comb9e to =m a ?ird sub/ance diff]5t f bo?1 unless _! compon5t p>ticles unite 9 def9ite proportions2 t is to say1 "o "p by weight ( "o ( ! sub/ances w unite ) "o "p by weight ( ! o!r1 or ) two p>ts1 or ?ree1 or f\r1 c41 s z to =m a new sub/ance2 b 9 any o!r proportions !y w only be me*anically mix$4 ,= example1 "o "p by weight ( hydrog5 gas w comb9e ) eight p>ts by weight ( oxyg5 gas1 & =m wat]2 or x w unite ) sixte5 p>ts by weight ( oxyg51 & =m a sub/ance call$ deutoxide ( hydrog52 b1 add$ to any o!r weight ( oxyg51 x w produce "o or bo? ( ^! comp\nds m+l$ ) ! portion ( oxyg5 or hydrog5 9 excess4 ,! law ( def9ite proportion e/abli%$ by ,dr4 ,dalton1 on ! pr9ciple t e comp\nd body consi/s ( a comb9ation ( ! atoms ( its con/itu5t p>ts1 is ( univ]sal application1 & is 9 fact "o ( ! mo/ important discov]ies 9 physical sci5ce1 furni%+ in=mation previ\sly unhop$ = ) reg>d to ! mo/ secret & m9ute op]ations ( nature1 9 disclos+ ! relative weights ( ! ultimate atoms ( matt]4 ,?us an atom ( oxyg5 unit+ ) an atom ( hydrog5 =ms ! comp\nd wat]2 b1 z e drop ( wat] h[ev] small consi/s ( eight p>ts by weight ( oxyg5 & "o "p by weight ( hydrog51 x foll[s t an atom ( oxyg5 is eight times heavi] ?an an atom ( hydrog54 ,9 ! same mann] sulphurett$ hydrog5 gas consi/s ( sixte5 p>ts by weight ( sulphur & "o ( hydrog52 !re=e an atom ( sulphur is sixte5 times heavi] ?an an atom ( hydrog54 ,also c>bonic oxide is con/itut$ ( six p>ts by weight ( c>bon & eight ( oxyg52 &1 z an atom ( oxyg5 has eight times ! weight ( an atom ( hydrog51 x foll[s t an atom ( c>bon is six times heavi] ?an "o ( hydrog54 ,s9ce ! same def9ite proportion holds 9 ! composition ( a va/ numb] ( sub/ances t h be5 exam9$1 x has be5 conclud$ t !re are great diff]5ces 9 ! weights ( ! ultimate p>ticles ( matt]4 ,al?\gh ,dalton's law is fully e/abli%$1 yet in/ances h occurr$ f :i* x appe>s t ! atomic !ory d$uc$ f x is n always ma9ta9$4 ,m4 ,gay ,lussac discov]$ t gases unite toge!r by _! bulk or volumes1 9 su* simple & def9ite proportions z "o to "o1 "o to two1 "o to ?ree1 c4 ,= example1 "o volume or measure ( oxyg5 unites ) two volumes or measures ( hydrog5 9 ! =mation ( wat]4 ,dr4 ,f>aday has prov$1 by exp]im5ts on bodies bo? 9 solution & fusion1 t *emical aff9ity is m]ely a result ( ! electrical /ate ( ! p>ticles ( matt]4 ,n[ x mu/ be obs]v$ t ! composition ( bodies1 z well z _! decomposition1 may be accompli%$ by means ( electricity2 & ,dr4 ,f>aday has f\nd t ?is *emical composition & decomposition1 by a giv5 curr5t ( electricity1 is always accompli%$ accord+ to ! laws ( def9ite proportions2 & t ! quantity ( electricity requisite = ! decomposition ( a sub/ance is exactly ! quantity necess>y = its composition4 ,?us ! quantity ( electricity :i* c decompose a gra9 weight ( wat] is exactly equal to ! quantity ( electricity :i* unites ! elem5ts ( t gra9 ( wat] toge!r1 & is equival5t to ! quantity ( atmosph]ic electricity :i* is active 9 a v p[]ful fla% ( lightn+4 ,?is law is univ]sal1 & ( t high & g5]al ord] :i* *>act]ises all great discov]ies4 ,*emical =ce is extremely p[]ful4 ,a p\nd ( ! be/ coal gives :5 burnt suffici5t heat to raise ! temp]ature ( #hjhf p\nds ( wat] "o ,c5tigrade degree1 :5ce ,pr(essor ,helmholtz ( ,bonn has comput$ t ! magnitude ( ! *emical =ce ( attraction betwe5 ! p>ticles ( a p\nd ( coal & ! quantity ( oxyg5 t corresponds to x1 is capable ( lift+ a weight ( #ajj p\nds to ! height ( #bj miles4 ,dr4 ,f>aday has giv5 a s+ul> in/ance ( cohesive =ce induc+ *emical comb9ation1 by ! foll[+ exp]im5t1 :i* seems to be ne>ly alli$ to ! discov]y made by ,m4 ,db]e9]1 9 #ahbc1 ( ! spontane\s combu/ion ( spongy plat9um 7,n4 #aga7 expos$ to a /ream ( hydrog5 gas mix$ ) common air4 ,a plate ( plat9um ) extremely clean surfaces1 :5 plung$ into oxyg5 & hydrog5 gas mix$ 9 ! proportions :i* are f\nd 9 ! con/itution ( wat]1 causes ! gases to comb9e & wat] to be =m$1 ! plat9um to become r$-hot1 & at la/ an explosion to take place2 ! only conditions necess>y = ?is curi\s exp]im5t be+ excessive purity 9 ! gases & 9 ! surface ( ! plate4 ,a suffici5tly pure metallic surface c only be obta9$ by imm]s+ ! plat9um 9 v /rong hot sulphuric acid & !n wa%+ x 9 di/ill$ wat]1 or by mak+ x ! positive pole ( a galvanic pile 9 dilute sulphuric acid4 ,x appe>s t ! =ce ( cohesion1 z well z ! =ce ( aff9ity1 ex]t$ by p>ticles ( matt]1 ext5ds to all ! p>ticles )9 a v m9ute di/ance4 ,h5ce ! plat9um1 :ile draw+ ! p>ticles ( ! two gases t[>ds its surface by its great cohesive attraction1 br+s !m s ne> to "o ano!r t !y come )9 ! sph]e ( _! mutual aff9ity1 & a *emical comb9ation takes place4 ,dr4 ,f>aday attributes ! effect 9 "p also to a dim9ution 9 ! ela/icity ( ! gase\s p>ticles on _! sides adjac5t to ! plat9um1 & to _! p]fect mixture or association1 z well z to ! positive action ( ! metal 9 cond5s+ !m aga9/ its surface by its attractive =ce4 ,! p>ticles :5 *emically unit$ run (f ! surface ( ! metal 9 ! =m ( wat] by _! gravitation1 or pass away z aque\s vap\r & make way = o!rs4 ,! oscillations ( ! atmosph]e1 & ! *anges 9 its temp]ature1 are measur$ by v>iations 9 ! heights ( ! b>omet] & !rmomet]4 ,b ! actual l5g? ( ! liquid columns dep5ds n only ^u ! =ce ( gravitation1 b ^u ! cohesive =ce or reciprocal attraction betwe5 ! molecules ( ! liquid & ^? ( ! tube conta9+ x4 ,?is peculi> action ( ! cohesive =ce is call$ capill>y attraction or capill>ity4 ,if a glass tube ( extremely f9e bore1 su* z a small !rmomet] tube1 be plung$ into a cup ( wat] or _s ( w9e1 ! liquid w imm$iately rise 9 ! tube above ! level ( t 9 ! cup2 & ! surface ( ! little column ?us susp5d$ w be a holl[ hemisph]e1 ^: diamet] is ! int]ior diamet] ( ! tube4 ,if ! same tube be plung$ into a cupful ( m]cury1 ! liquid w also rise 9 ! tube1 b x w nev] atta9 ! level ( t 9 ! cup1 & its surface w be a hemisph]e ^: diamet] is also ! diamet] ( ! tube 7,n4 #agb74 ,! elevation or depression ( ! same liquid 9 diff]5t tubes ( ! same matt] is 9 ! inv]se ratio ( _! int]nal diamet]s 7,n4 #agc71 & altoge!r indep5d5t ( _! ?ickness2 :5ce x foll[s t ! molecul> action is ins5sible at s5sible di/ances1 & t x is only ! ?9ne/ possible film ( ! int]ior surface ( ! tubes t ex]ts a s5sible action on ! liquid4 ,s mu* inde$ is ?is ! case1 t1 :5 tubes ( ! same bore are completely wett$ ) wat] ?r\gh\t _! :ole ext5t1 m]cury w rise to ! same height 9 all ( !m1 :atev] be _! ?ickness or d5sity1 because ! m9ute coat+ ( moi/ure is suffici5t to remove ! int]nal column ( m]cury beyond ! sph]e ( attraction ( ! tube1 & to supply ! place ( a tube by its own capill>y attraction4 ,! =ces :i* produce ! capill>y ph5om5a are ! reciprocal attraction ( ! tube & ! liquid1 & ( ! liquid p>ticles on "o ano!r2 &1 9 ord] t ! capill>y column may be 9 equilibrio1 ! weight ( t "p ( x :i* rises above or s9ks bel[ ! level ( ! liquid 9 ! cup mu/ balance ^! =ces4 ,! e/imation ( ! action ( ! liquid is a difficult "p ( ?is problem4 ,la ,place1 ,dr4 ,"y1 & o!r ma!maticians1 h consid]$ ! liquid )9 ! tube to be ( uni=m d5sity2 b ,m4 ,poisson1 9 "o ( ^? ma/]ly productions 9 :i* he elucidates ! mo/ ab/ruse subjects1 has prov$ t ! ph5om5a ( capill>y attraction dep5d ^u a rapid decrease 9 ! d5sity ( ! liquid column ?r\gh\t an extremely small space at its surface4 ,e indef9itely ?9 lay] ( a liquid is compress$ by ! liquid above x1 & support$ by t bel[4 ,its degree ( cond5sation dep5ds ^u ! magnitude ( ! compressive =ce2 &1 z ?is =ce decreases rapidly t[>ds ! surface1 :]e x vani%es ! d5sity ( ! liquid decreases also4 ,m4 ,poisson has %[n t1 :5 ?is =ce is omitt$1 ! capill>y surface becomes plane1 & t ! liquid 9 ! tube w nei!r rise above nor s9k bel[ ! level ( t 9 ! cup4 ,9 e/imat+ ! =ces1 x is also necess>y to include ! v>iation 9 ! d5sity ( ! capill>y surface r\nd ! edges f ! attraction ( ! tube4 ,! direction ( ! result+ =ce det]m9es ! curvature ( ! surface ( ! capill>y column4 ,9 ord] t a liquid may be 9 equilibrio1 ! =ce result+ f all ! =ces act+ ^u x mu/ be p]p5dicul> to ! surface4 ,n[ x appe>s t1 z glass is m d5se ?an wat] or alcohol1 ! result+ =ce w be incl9$ t[>ds ! int]ior side ( ! tube2 !re=e ! surface ( ! liquid mu/ be m elevat$ at ! sides ( ! tube ?an 9 ! c5tre 9 ord] to be p]p5dicul> to x1 s t x w be concave z 9 ! !rmomet]4 ,b1 z glass is less d5se ?an m]cury1 ! result+ =ce w be incl9$ f ! int]ior side ( ! tube 7,n4 #agd71 s t ! surface ( ! capill>y column mu/ be m depress$ at ! sides ( ! tube ?an 9 ! c5tre1 9 ord] to be p]p5dicul> to ! result+ =ce1 & is consequ5tly convex1 z may be p]ceiv$ 9 ! m]cury ( ! b>omet] :5 ris+4 ,! absorption ( moi/ure by sponges1 sug>1 salt1 c41 are famili> examples ( capill>y attraction4 ,inde$ ! pores ( sug> are s m9ute1 t !re seems to be no limit to ! asc5t ( ! liquid4 ,w9e is drawn up 9 a curve on ! int]ior surface ( a glass2 tea rises above its level on ! side ( a cup2 b1 if ! glass or cup be too full1 ! edges attract ! liquid d[nw>ds1 & give x a r\nd$ =m4 ,a column ( liquid w rise above or s9k bel[ its level betwe5 two plane p>allel surfaces :5 ne> to "o ano!r1 accord+ to ! relative d5sities ( ! plates & ! liquid 7,n4 #age72 & ! ph5om5a w be exactly ! same z 9 a cyl9drical tube ^: diamet] is d\ble ! di/ance ( ! plates f ea* o!r4 ,if ! two surfaces be v ne> to "o ano!r1 & t\* ea* o!r at "o ( _! upright edges1 ! liquid w rise highe/ at ! edges t are 9 contact1 & w gradually dim9i% 9 height z ! surfaces become m sep>at$4 ,! :ole outl9e ( ! liquid column w h ! =m ( a hyp]bola4 ,inde$1 s univ]sal is ! action ( capill>ity1 t solids & liquids _c t\* "o ano!r )\t produc+ a *ange 9 ! =m ( ! surface ( ! liquid4 ,! attractions & repulsions aris+ f capill>ity pres5t _m curi\s ph5om5a4 ,if two plates ( glass or metal1 bo? ( :i* are ei!r dry or wet1 be p>tly imm]s$ 9 a liquid p>allel to "o ano!r1 ! liquid w be rais$ or depress$ close to _! surfaces1 b w ma9ta9 its level ?r\gh ! re/ ( ! space t sep>ates !m4 ,at su* a di/ance !y nei!r attract nor repel "o ano!r2 b ! in/ant !y are br\ght s ne> z to make ! level "p ( ! liquid disappe>1 & ! two curv$ p>ts ( x meet1 ! two plates w ru% t[>ds ea* o!r & rema9 press$ toge!r 7,n4 #agf74 ,if "o ( ! surfaces be wet & ! o!r dry1 !y w repel "o ano!r :5 s ne> z to h a curv$ surface ( liquid betwe5 !m2 b1 if =c$ to approa* a little ne>]1 ! repulsion w be ov]come1 & !y w attract ea* o!r z if !y 7 bo? wet or bo? dry4 ,two balls ( pi? or wood float+ 9 wat]1 or two balls ( t9 float+ 9 m]cury1 attract "o ano!r z soon z !y are s ne> t ! surface ( ! liquid is curv$ betwe5 !m4 ,two %ips 9 ! ocean may be br\ght into collision by ?is pr9ciple4 ,b two balls1 "o ( :i* is wet & ! o!r dry1 repel "o ano!r z soon z ! liquid :i* sep>ates !m is curv$ at its surface4 ,a bit ( tea-leaf is attract$ by ! edge ( ! cup if wet1 & repell$ :5 dry1 provid$ x be n too f> f ! edge & ! cup mod]ately full2 if too full1 ! contr>y takes place4 ,x is probable t ! rise ( ! sap 9 vegetables is 9 "s degree ow+ to capill>ity4 ,,section ,,xv4 ,analysis ( ! ,atmosph]e--,its ,pressure--,law ( ,decrease 9 ,d5sity--,law ( ,decrease 9 ,temp]ature--,measurem5t ( ,heights by ! ,b>omet]--,ext5t ( ! ,atmosph]e--,b>ometrical ,v>iations--,oscillations--,trade-,w9ds- -,cl\d-,r+--,monsoons--,rotation ( ,w9ds--,laws ( ,hurricanes4 ,,! atmosph]e is n homog5e\s4 ,x appe>s f analysis t1 ( #ajj p>ts1 #iie consi/ ( nitrog5 & oxyg5 gases mix$ 9 ! proportions ( #gi to #ba ( volume1 ! rema9d] consi/s ( #jje p>ts ( c>bonic acid & on an av]age #jde ( aque\s vap\r4 ,^! proportions are f\nd to be ! same at all heights hi!rto atta9$ by man4 ,! air is an ela/ic fluid1 resi/+ pressure 9 e direction1 & is subject to ! law ( gravitation4 ,z ! space 9 ! top ( ! tube ( a b>omet] is a vacuum1 ! column ( m]cury susp5d$ by ! pressure ( ! atmosph]e on ! surface ( t 9 ! ci/]n is a measure ( its weight4 ,consequ5tly e v>iation 9 ! d5sity occasions a correspond+ rise or fall 9 ! b>ometrical column4 ,at ! level ( ! sea 9 latitude #db1 & at ! temp]ature ( melt+ ice1 ! mean height ( ! b>omet] is #biibb or #cj in*es ne>ly4 ,! pressure ( ! atmosph]e is ab\t fifte5 p\nds on e squ>e in*2 s t ! surface ( ! :ole globe su/a9s a weight ( #aa1fga1jjj1jjj hundr$s ( millions ( p\nds4 ,%ell-fi%1 :i* h ! p[] ( produc+ a vacuum1 adh]e to ! rocks by a pressure ( fifte5 p\nds ^u e squ>e in* ( contact4 ,! atmosph]e :5 9 equilibrio is an ellipsoid flatt5$ at ! poles f its rotation ) ! e>?4 ,9 t /ate its /rata are ( uni=m d5sity at equal heights above ! level ( ! sea2 b s9ce ! air is bo? heavy & ela/ic1 its d5sity necess>ily dim9i%es 9 asc5d+ above ! surface ( ! e>?2 = ea* /ratum ( air is compress$ only by ! weight above x4 ,!re=e ! upp] /rata are less d5se because !y are less compress$ ?an ^? bel[ !m4 ,:5ce x is easy to %[1 suppos+ ! temp]ature to be con/ant1 t if ! heights above ! e>? be tak5 9 increas+ ari?metical progression1 t is1 if !y increase by equal quantities1 z by a foot or a mile1 ! d5sities ( ! /rata ( air1 or ! heights ( ! b>omet] :i* are proportionate to !m1 w decrease 9 geometrical progression4 ,= example1 at ! level ( ! sea if ! mean height ( ! b>omet] be #biibb in*es1 at ! height ( #ah1jjj feet x w be #adifa in*es1 or "o half z great2 at ! height ( #cf1jjj feet x w be "o-f\r? z great2 at #ed1jjj feet x w be "o-eigh?1 & s on4 ,sir ,john ,h]s*el has %[n t ! actual decrease is mu* m rapid1 & t1 9 any hypo!sis t has be5 =m$ ) reg>d to ! divisibility ( ! arial atoms1 a vacuum exi/s at ! height ( #hj or #ij miles above ! e>?'s surface1 inconceivably m p]fect ?an any t c be produc$ 9 ! be/ air-pumps4 ,inde$ ! decrease 9 d5sity is s rapid t ?ree-f\r?s ( all ! air conta9$ 9 ! atmosph]e is )9 f\r miles ( ! e>?2 &1 z its sup]ficial ext5t is #bjj millions ( squ>e miles1 its relative ?ickness is less ?an t ( a %eet ( pap] :5 comp>$ ) its bread?4 ,! air ev5 on m\nta9 tops is suffici5tly r>e to dim9i% ! int5sity ( s\nd1 to affect respiration1 & to occasion a loss ( muscul> /r5g?4 ,! blood bur/ f ! lips & e>s ( ,m4 de ,humboldt z he asc5d$ ! ,&es2 & he exp]i5c$ ! same difficulty 9 k9dl+ & ma9ta9+ a fire at great heights :i* ,m>co ,polo1 ! ,v5etian1 felt on ! m\nta9s ( ,c5tral ,asia4 ,m4 ,gay-,lussac asc5d$ 9 a balloon to ! height ( #dcf miles1 & he suff]$ greatly f ! r>ity ( ! air4 ,x is true t at ! height ( ?irty-sev5 miles ! atmosph]e is /ill d5se en\gh to reflect ! rays ( ! sun :5 #ah bel[ ! horizon2 b ! tails ( comets %[ t extremely att5uat$ matt] is capable ( reflect+ light4 ,& al?\gh1 at ! height ( fifty miles1 ! bur/+ ( ! meteor ( #aghc 0 he>d on e>? l ! report ( a cannon1 x only proves ! imm5sity ( ! explosion ( a mass half a mile 9 diamet]1 :i* c\ld produce a s\nd capable ( p5etrat+ air ?ree ?\s& times m r>e ?an t we brea!4 ,b ev5 ^! heights are extremely small :5 comp>$ ) ! radius ( ! e>?4 ,! d5sity ( ! air is modifi$ by v>i\s circum/ances1 *iefly by *anges ( temp]ature1 because heat dilates ! air & cold contracts x1 v>y+ #a_/dhj ( ! :ole bulk :5 at #cb = e degree ( ,fahr5heit's !rmomet]4 ,exp]i5ce %[s t ! heat ( ! air decreases z ! height above ! surface ( ! e>? increases4 ,x appe>s t ! mean temp]ature ( space is #bbf bel[ ! z]o po9t ( ,fahr5heit by ! !ories ( ,f\ri] & ,p\illet1 b ,sir ,john ,h]s*el has comput$ x to be -#bci ,fahr4 f obs]vations made dur+ ! asc5t 9 balloons4 ,su* w\ld probably be ! temp]ature ( ! surface ( ! e>? also1 7 x n = ! non-conduct+ p[] ( ! air1 :5ce x is enabl$ to reta9 ! heat ( ! sun's rays1 :i* ! e>? imbibes & radiates 9 all directions4 ,! decrease 9 heat is v irregul>2 ea* au?ority gives a diff]5t e/imate1 because x v>ies ) latitude & local circum/ances1 b f ! mean ( five diff]5t /atem5ts x seems to be ab\t "o degree = e #ccd feet2 ! mean ( obs]vations made 9 balloons is #djj feet1 :i* is probably ne>] ! tru?4 ,?is is ! cause ( ! sev]e cold & p]petual sn[ on ! summits ( ! alp9e *a9s4 ,9 ! ye> #aheb f\r asc5ts 9 a balloon took place f ! meteorological obs]vatory at ,kew1 9 :i* ! greate/ height atta9$ 0 #bb1cgj feet4 ,! obs]vations !n made by ,mr4 ,wel% furni%$ ,sir ,john ,h]s*el ) data = comput+ t ! temp]ature ( space is m9us #bci1 t is #bci bel[ ! z]o po9t ( ,fahr5heit1 t ! limit+ temp]ature ( ! atmosph]e is probably #gg-a_/b degrees bel[ t po9t at ! equator1 & #aai-a_/b bel[ x at ! poles1 ) a range ( temp]ature f ! surface ( #afa-a_/b 9 ! =m] case1 & #aai-a_/b 9 ! latt]4 ,dur+ ^! asc5ts x 0 f\nd t ! temp]ature ( ! air decreases uni=mly up to a c]ta9 po9t1 :]e x is arre/$ & rema9s con/ant1 or increases ?r\gh a dep? ( #bjjj or #cjjj feet1 aft] :i* x decreases aga9 accord+ to ! same law z be=e4 ,?r\gh\t ?is zone ( con/ant temp]ature x ei!r ra9s1 or !re is a great fall 9 ! dew po9t2 9 %ort1 x is ! region ( cl\ds1 & ! increase ( temp]ature is ow+ to ! lat5t or absorb$ heat set free by ! cond5sation ( ! aque\s vap\r4 ,9 ! latitude ( ,kew ! cl\d region beg9s at altitudes v>y+ betwe5 #bjjj & #fejj feet1 accord+ to ! /ate ( ! wea!r4 ,7 x n = ! effects ( temp]ature on ! d5sity ( ! air1 ! heights ( m\nta9s might be det]m9$ by ! b>omet] alone2 b z ! !rmomet] mu/ also be consult$1 ! det]m9ation becomes m complicat$4 ,mr4 ,ivory's me?od ( comput+ heights f b>ometrical measurem5ts has ! advantage ( comb9+ accuracy ) ! greate/ simplicity4 ,inde$ ! accuracy ) :i* ! heights ( m\nta9s c be obta9$ by ?is me?od is v rem>kable4 ,admiral ,smy?1 ,r4,n41 & ,sir ,john ,h]s*el measur$ ! height ( ,etna by ! b>omet]1 )\t any communication & 9 diff]5t ye>s2 ,admiral ,smy? made x #aj1hgd feet1 & ,sir ,john ,h]s*el #aj1hgc1 ! diff]5ce be+ only "o foot4 ,9 consequ5ce ( ! dim9i%$ pressure ( ! atmosph]e wat] boils at a l[] temp]ature on m\nta9 tops ?an 9 ! valleys1 :i* induc$ ,fahr5heit to propose ?is mode ( obs]vation z a me?od ( asc]ta9+ _! heights4 ,x is v simple1 z ,pr(essor ,=bes asc]ta9$ t ! temp]ature ( ! boil+ po9t v>ies 9 ari?metical proportion ) ! height1 or #edie feet = e degree ( ,fahr5heit1 s t ! calculation ( height becomes "o ( ari?metic only1 )\t ! use ( any table4 ,! mean pressure ( ! atmosph]e is n ! same all ov] ! globe4 ,x is less by #jbd ( an in* at ! equator ?an at ! tropics or 9 ! high] latitudes1 9 consequ5ce ( ! asc5t ( heat$ air & vap\r f ! surface ( ! ocean4 ,x is less also on ! %ores ( ! ,baltic ,sea ?an x is 9 ,france1 & x 0 obs]v$ by ,sir ,james ,c4 ,ross t ?r\gh\t ! :ole ( ! ,ant>ctic ,ocean1 f #fh to #gd ,s4 latitude1 & f #h to #g ,w4 longitude1 !re is a depression ( ! b>omet] am\nt+ to an in* & upw>ds1 :i* is equival5t to an elevation above ! sea level ( #hjj feet4 ,a simil> depression 0 obs]v$ by ,m4 ,erman 9 ! sea ( ,o*otzk1 & 9 ! adjac5t cont95t ( ea/]n ,sib]ia4 ,sir ,john ,h]s*el assigns z ! cause ( ^! s+ul> anomalies ! great sy/em ( circulation ( ! trade & antetrade w9ds1 9 bo? hemisph]es1 react+ ^u ! g5]al mass ( ! cont95ts z ob/acles 9 _! pa?1 :i* is modifi$ by ! configuration ( ! l&4 ,!re are v>i\s p]iodic oscillations 9 ! atmosph]e1 :i*1 ris+ & fall+ l waves 9 ! sea1 occasion correspond+ *anges 9 ! height ( ! b>omet]1 b !y diff] z mu* f ! trade-w9ds1 monsoons1 & o!r curr5ts1 z ! tides ( ! sea d f ! ,gulf-/ream & o!r oceanic riv]s4 ,! sun & moon di/urb ! equilibrium ( ! atmosph]e by _! attraction1 & produce annual undulations :i* h _! maximum altitudes at ! equ9oxes1 & _! m9ima at ! sol/ices4 ,!re are also lun> tides1 :i* ebb & fl[ twice 9 ! c\rse ( a lunation4 ,! diurnal tides1 :i* accompli% _! rise & fall 9 six h\rs1 are greatly modifi$ by ! heat ( ! sun4 ,betwe5 ! tropics ! b>omet] atta9s its maximum height ab\t n9e 9 ! morn+1 !n s9ks till ?ree or f\r 9 ! aft]noon2 x aga9 rises & atta9s a second maximum ab\t n9e 9 ! ev5+1 & !n x beg9s to fall1 & rea*es a second m9imum at ?ree 9 ! morn+1 aga9 to pursue ! same c\rse4 ,accord+ to ,m4 ,b\v>d1 ! am\nt ( ! oscillations at ! equator is proportional to ! temp]ature1 & 9 o!r p>allels x v>ies z ! temp]ature & ! squ>e ( ! cos9e ( ! latitude conjo9tly2 consequ5tly x decreases f ! equator to ! poles1 b x is some:at great] 9 ! day ?an 9 ! night4 ,besides ^! small undulations1 !re are va/ waves p]petually mov+ ov] ! cont95ts & oceans 9 sep>ate & indep5d5t sy/ems1 be+ conf9$ to local1 yet v ext5sive di/ricts1 probably occasion$ by long-cont9u$ ra9s or dry wea!r ov] l>ge tracts ( c\ntry4 ,by num]\s b>ometrical obs]vations made simultane\sly 9 bo? hemisph]es1 ! c\rses ( sev]al h be5 trac$1 "s ( :i* occupy tw5ty-f\r1 & o!rs ?irty-six1 h\rs to accompli% _! rise & fall4 ,"o especially ( ^! va/ b>ometric waves1 _m hundr$s ( miles 9 bread?1 has be5 trac$ ov] ! great] "p ( ,europe2 & n its bread? only1 b also ! direction ( its front & its velocity1 h be5 cle>ly asc]ta9$4 ,al?\gh1 l all o!r waves1 ^! are b mov+ =ms1 yet w9ds arise dep5d5t on !m l tide /reams 9 ! ocean4 ,mr4 ,birt has det]m9$ ! p]iods ( o!r waves ( /ill great] ext5t & duration1 two ( :i* requir$ sev5te5 days to rise & fall2 & ano!r :i* takes f\rte5 days to complete its undulation1 call$ by ,mr4 ,birt ! ,novemb] wave1 passes annually ov] ! ,briti% ,isl&s1 probably ov] ! :ole ( ,europe & ! seas on its nor!rn coa/s4 ,its cre/1 :i* appe>s to be #fjjj miles 9 ext5t1 moves f ,n4,w4 to ,s4,e4 at ! rate ( ab\t #ai miles an h\r2 :ile ! ext5t ( its b>ometrical elevation f its tr\gh to its cre/ is seldom less ?an an in*1 sometimes d\ble t quantity4 ,! great cre/ is prec$$ & foll[$ at ab\t five days' int]val by two l[] ones1 & ! beg9n+ & end are m>k$ by deep depressions4 ,! rese>*es ( ,m4 ,lev]ri] leave no d\bt t ! great ,crimean /orm ( ! #ad? ,novemb]1 #ahed1 0 "p ( ?is ph5om5on1#h = ev5 a v small diff]5ce ( atmosph]ic pressure is suffici5t to raise a consid]able w9d4 ,s9ce ea* oscillation has its p]fect effect indep5d5tly ( ! o!rs1 ea* "o is m>k$ by a *ange 9 ! b>omet]1 & ?is is beautifully illu/rat$ by curves con/ruct$ f a s]ies ( obs]vations4 ,! g5]al =m ( ! curve %[s ! c\rse ( ! pr9cipal wave1 :ile small undulations 9 its outl9e m>k ! maxima & m9ima ( ! m9or oscillations4 ,! trade-w9ds1 :i* are ! pr9cipal curr5ts 9 ! atmosph]e1 are only a p>ticul> case ( ^? v g5]al laws :i* regulate ! motion ( ! w9ds dep5d+ on ! r>efaction ( ! air comb9$ ) ! rotation ( ! e>? on its axis4 ,!y are p]man5t curr5ts ( w9d betwe5 ! tropics1 bl[+ to ! ,n4,e4 on ! ,n4 side ( ! equator1 & to ! ,s4,e4 on ! ,s4 side4 ,if curr5ts ( air come f ! poles1 x is cle> t equilibrium mu/ be re/or$ by c\nt]-curr5ts f ! equator2 moreov]1 w9ds com+ f ! poles1 :]e !re is no rotation1 to ! equator1 :i* revolves f ,w4 to ,e4 at ! rate ( #ajjj miles an h\r1 mu/ ( necessity move 9 a direction result+ f _! own progressive motion & t ( rotation2 h5ce1 9 bl[+ t[>ds ! equator ! bias is to ! ,e41 & 9 bl[+ f x ! bias is to ! ,w4 ,?us z ,n4 & ,s4 w9ds f ! poles bl[ along ! surface f ! tropics to ! equator1 9 consequ5ce ( ?is composition ( motions t f ! ,n4 becomes ! ,n4,e4 trade-w9d1 & t f ! ,s4 ! ,s4,e4 trade-w9d4 ,n[ ^! w9ds be+ 9 contr>y directions cross at ! equator1 balance ea* o!r ?r\gh ab\t #f degrees ( latitude1 & produce a belt ( calms ( t bread? encircl+ ! globe1 kn[n z ! calms ( ! equator1 or ! ,v>iables ( seam54 ,! heat ( ! sun r>efies ! air s mu*1 t ! trade-w9ds1 aft] cross+ at ! equator1 asc5d into ! high] regions ( ! atmosph]e1 :]e t f ! ,n4 goes to ! tropic ( ,capricorn1 & t f ! ,s4 to ! tropic ( ,canc]4 ,b :ile travell+ 9 ^! l(ty regions !y become cold & heavy1 &1 s9k+ to ! surface at ! tropics1 ea* proce$s to ! opposite pole f :i* x set out4 ,n[1 h[ev]1 !y h a great] rotatory motion ?an ! places !y successively arrive at1 s ! bias is to ! ,w41 & !y become ! ,n4,w4 & ,s4,w4 extra-tropical w9ds4 ,if on arriv+ at ! poles ! air 7 to accumulate !re1 ! circulation ( ! w9ds w\ld cease2 b curr5ts rise into ! upp] regions1 & fl[ back aga9 to ! tropics1 :]e !y s9k d[n to fill ! vacuum caus$ by ! great precipitation ( vap\r 9 ^! regions1 & !n fl[ to ! equator z trade-w9ds 7,n4 #agg74 ,s ! curr5ts ( air cross aga9 at ! tropics & produce two belts ( calms :i* surr\nd ! globe1 nam$ by ,lieut5ant ,maury ! ,calms ( ,canc] & ! ,calms ( ,capricorn1 b g5]ally kn[n to sailors z ! ,doldrums4 ,?us ! w9ds g f pole to pole & back aga91 alt]nately z "u & upp] curr5ts4 ,9 _! circuits ! w9ds cross ea* o!r five times1 produc+ regions ( calms at ! poles1 ! tropics1 & equator4 ,! trade-w9ds g5]ally ext5d = ab\t #bh on ea* side ( ! equator1 b1 on acc\nt ( ! great] quantity ( l& 9 ! nor!rn hemisph]e1 ! ,n4,e4 trade-w9d is n>r[] ?an ! ,s4,e4 ,! sun is p]petually rais+ enorm\s quantities ( vap\r f ! ocean :i* ! trade-w9ds c>ry to ! equator3 x is cond5s$ :5 x rises ) ! air into ! high] /rata1 & =ms a r+ ( cl\ds along ! s\!rn side ( ! belt ( equatorial calms t surr\nds ! e>?1 :i*1 dur+ ! day1 is p]petually p\r+ d[n torr5ts ( ra91 :ile ! sun cont9ually beat+ ^u its upp] surface dissolves ! cl\ds into invisible vap\r :i* is c>ri$ by ! w9ds & cond5s$ into ra9 on ! extra-tropical regions4 ,! :ole sy/em ( trade-w9ds1 equatorial & tropical calms1 ) ! cl\d r+1 foll[ ! sun 9 decl9ation2 consequ5tly 9 its j\rneys back & =w>ds x annually travels ov] #ajjj miles ( latitude1 & regulates ! dry & ra9y season 9 ! tropical p>ts ( ! e>?4 ,! monsoons1 :i* are p]iodic w9ds 9 ! ,indian ,ocean1 9 "p dep5d ^u ?is movem5t4 ,= :5 ! sun is 9 ! nor!rn hemisph]e ! trade-w9ds come nor?w>d ) him2 & :5 8 int5se heat exp&s ! air ov] ! ,great ,gobi & o!r arid ,asiatic des]ts1 x asc5ds2 ! ,n4,e4 trade-w9d is drawn 9 to fill ! vacuum & asc5ds ) x2 !n ! ,s4,e4 trade-w9d1 be+ no long] met & balanc$ by ! ,n4,e4 trade1 passes into ! nor!rn hemisph]e1 & z x proce$s nor?w>d f ! equator x is deflect$ to ! we/ by ! rotation ( ! e>?1 comb9$ ) ! indraught ov] ! heat$ des]ts1 & becomes ! ,s4,w4 monsoon1 :i* bl[s :ile ! sun is nor? ( ! equator1 b z soon z he goes s\?1 & no long] r>efies ! air ov] ! ,indian des]ts1 ! ,s4,e4 trade-w9d resumes its usual c\rse1 & is !n kn[n z ! ,s4,e4 monsoon4 ,! influ5ce ( ! heat$ des]ts is p]ceptible to ! di/ance ( #ajjj miles f ! %ore2 ! monsoons prevail ) great /ead9ess ov] ! ,arabian ,gulf1 ! ,indian ,ocean1 & "p ( ! ,*9a ,sea4 ,at ! *ange1 torr5ts ( ra9 & viol5t ?und]/orms accompany ! conflict betwe5 ! cont5d+ w9ds4 ,! ,sah>a des]t 9 ,nor? ,africa1 & ^? ( ,utah1 ,texas1 & ,new ,mexico1 occasion ! monsoons :i* prevail 9 ! ,nor? ,atlantic & on bo? sides ( ,c5tral ,am]ica1 & ! monsoons :i* bl[ to ! nor? ( ,au/ralia %[ ! /]ility ( ! int]ior1 ev5 if o!r pro(s 7 want+4 ,f ! p[]ful effect ( ! l& 9 draw+ (f ! w9ds f _! c\rse1 x may be se5 :y ! ,n4,e4 trade-w9ds are n>r[] ?an ! ,s4,e4 trades4 ,9 ! extra-tropical w9ds 9 ! ,nor? ,atlantic1 :i* bl[ f ! #dj? p>allel to ! pole1 ! nor?-we/]ly are to ! ea/]ly z #b to #a3 h5ce !re w\ld be an accumulation ( air at ! pole at ! exp5se ( ! equator1 did n a curr5t rise at ! pole & return to ! equator ?r\gh ! high regions ( ! atmosph]e1 :i* confirms ! !ory ( ! rotation ( ! w9d4 ,!re are _m pro(s ( ! exi/5ce ( ! c\nt]-curr5ts above ! trade-w9ds4 ,on ! ,peak ( ,t5]iffe ! prevail+ w9ds are f ! we/4 ,light cl\ds h frequ5tly be5 se5 mov+ rapidly f we/ to ea/ at a v great height above ! trade-w9ds1 :i* 7 sweep+ along ! surface ( ! ocean 9 a contr>y direction4 ,ra9s1 cl\ds1 & ne>ly all ! o!r atmosph]ic ph5om5a1 occur bel[ ! height ( #ah1jjj feet1 & g5]ally mu* ne>] to ! surface ( ! e>?4 ,!y are ow+ to curr5ts ( air runn+ ^u ea* o!r 9 horizontal /rata1 diff]+ 9 _! electric /ate1 9 temp]ature & moi/ure1 z well z 9 velocity & direction4 ,:5 nor? & s\? w9ds bl[ alt]nately1 ! w9d at any place w ve] 9 "o uni=m direction ?r\gh e po9t ( ! compass1 provid$ ! "o beg9s be=e ! o!r has ceas$4 ,9 ! nor!rn hemisph]e a nor? w9d sets out ) a small] degree ( rotatory motion ?an ! places h at :i* x successively arrives1 consequ5tly x passes ?r\gh all ! po9ts ( ! compass f ,n4 to ,n4,e4 & ,e4 ,a curr5t f ! s\?1 on ! contr>y1 sets out ) a great] rotatory velocity ?an ! places h at :i* x successively arrives1 s by ! rotation ( ! e>? x is deflect$ f ,s4 to ,s4,w4 & ,w4 ,n[1 if ! vane at any place %\ld h ve]$ f ! ,n4 ?r\gh ,n4,e4 to ,e41 & a s\? w9d %\ld spr+ up1 x w\ld comb9e its motion ) ! =m] & cause ! vane to turn successively f ! ,e4 to ,s4,e4 & ,s4 ,b by ! e>?'s rotation ?is s\? w9d w ve] to ! ,s4,w4 & ,w41 &1 if a nor? w9d %\ld n[ arise1 x w\ld comb9e its motion ) t ( ! we/1 & cause x to ve] to ! ,n4,w4 & ,n4 ,?us two alt]nations ( nor? & s\? w9d w cause ! vane at any place to g completely r\nd ! compass1 f ,n4 to ,e41 ,s41 ,w41 & ,n4 aga94 ,at ! ,royal ,obs]vatory at ,gre5wi* ! w9d accompli%es five circuits 9 t direction 9 ! c\rse ( a ye>4 ,:5 circum/ances comb9e to produce alt]nate nor? & s\? w9ds 9 ! s\!rn hemisph]e1 ! gyration is 9 ! contr>y direction4 ,al?\gh ! g5]al t5d5cy ( ! w9d may be rotatory1 & is s 9 _m in/ances1 at lea/ = "p ( ! ye>1 yet x is s (t5 c\nt]act$ by local circum/ances1 t ! w9ds are 9 g5]al v irregul>1 e di/urbance 9 atmosph]ic equilibrium f heat or any o!r cause produc+ a correspond+ w9d4 ,! mo/ preval5t w9ds 9 ,europe are ! ,n4,e4 & ,s4,w42 ! =m] arises f ! nor? pol> curr5t1 & ! latt] f causes already m5tion$4 ,! law ( ! w9d's rotation 0 fir/ describ$ by ,dr4 ,dalton1 b has be5 develop$ by ,pr(essor ,dove1 ( ,b]l94 ,hurricanes are ^? /orms ( w9d 9 :i* ! portion ( ! atmosph]e t =ms !m revolves 9 a horizontal circuit r\nd a v]tical or some:at incl9$ axis ( rotation1 :ile ! axis itself1 & consequ5tly ! :ole /orm1 is c>ri$ =w>d along ! surface ( ! globe1 s t ! direction 9 :i* ! /orm is advanc+ is q diff]5t f ! direction 9 :i* ! rotatory curr5t may be bl[+ at any po9t4 ,9 ! ,we/ ,indies1 :]e hurricanes are frequ5t & de/ructive1 !y g5]ally orig9ate 9 ! tropical regions ne> ! inn] b\nd>y ( ! trade-w9ds1 & are caus$ by ! v]tical asc5t ( a column ( r>efi$ air1 ^: place is suppli$ by a ru% ( w9d f ! surr\nd+ regions1 set into gyration by ! rotation ( ! e>?4 ,by f> ! great] numb] ( ,atlantic hurricanes h begun ea/w>d ( ! less] ,antilles or ,c>ibbean ,isl&s4 ,9 e case ! axis ( ! /orm moves 9 an elliptical or p>abolic curve1 hav+ its v]tex 9 or ne> ! tropic ( ,canc]1 :i* m>ks ! ext]nal limit ( ! trade-w9ds nor? ( ! equator4 ,z ! motion be=e x rea*es ! tropic is 9 a /raight l9e f ,s4,e4 to ,n4,w41 & aft] x has pass$ x f ,s4,w4 to ,n4,e41 ! b5d ( ! curve is turn$ t[>ds ,florida & ! ,c>ol9as4 ,9 ! s\!rn hemisph]e ! body ( ! /orm moves 9 exactly ! opposite direction4 ,! hurricanes :i* orig9ate s\? ( ! equator1 & ^: initial pa? is f ,n4,e4 to ,s4,w41 b5d r\nd at ! tropic ( ,capricorn1 & !n move f ,n4,w4 to ,s4,e4 ,! ext5t & velocity ( ^! /orms are great2 = in/ance1 ! hurricane t took place on ! #ab? ( ,augu/1 #ahcj1 0 trac$ f ea/w>d ( ! ,c>ibbee ,isl&s1 along ! ,gulf ,/ream1 to ! bank ( ,newf\ndl&1 a di/ance ( m ?an #cjjj miles1 :i* x pass$ ov] 9 six days4 ,al?\gh ! hurricane ( ! #a/ ( ,septemb]1 #ahba1 0 n s ext5sive1 its velocity 0 great]1 z x mov$ at ! rate ( #cj miles an h\r3 small /orms are g5]ally m rapid ?an ^? ( great] dim5sions4 ,! action ( ^! /orms seems to be at fir/ conf9$ to ! /ratum ( air ne>e/ ! e>?1 & !n !y seldom appe> to be m ?an a mile high1 ?\gh sometimes !y are rais$ high]2 or ev5 divid$ by a m\nta9 into two sep>ate /orms1 ea* ( :i* cont9ues its new pa? & gyrations ) increas$ viol5ce4 ,?is occurr$ 9 ! gale ( ! #be? ( ,decemb]1 #ahba1 9 ! ,m$it]ranean1 :5 ! ,spani% m\nta9s & ! ,m>itime ,alps became new c5tres ( motion4 ,by ! friction ( ! e>? ! axis ( ! /orm b5ds a little =w>d4 ,?is causes a cont9ual int]mixture ( ! l[] & w>m] /rata ( air ) ^? t are high] & cold]1 produc+ torr5ts ( ra9 & viol5t electric explosions4 ,! bread? ( ! :irlw9d is greatly augm5t$ :5 ! pa? ( ! /orm *anges on cross+ ! tropic4 ,! vortex ( a /orm has cov]$ an ext5t ( ! surface ( ! globe #ejj miles 9 diamet]4 ,! revolv+ motion acc\nts = ! sudd5 & viol5t *anges obs]v$ dur+ hurricanes4 ,9 consequ5ce ( ! rotation ( ! air1 ! w9d bl[s 9 opposite directions on ea* side ( ! axis ( ! /orm1 & ! viol5ce ( ! bla/ increases f ! circumf]5ce t[>ds ! c5tre ( gyration1 b 9 ! c5tre itself ! air is 9 repose3 h5ce1 :5 ! body ( ! /orm passes ov] a place1 ! w9d beg9s to bl[ mod]ately1 & increases to a hurricane z ! c5tre ( ! :irlw9d approa*es2 !n1 9 a mom5t1 a dead & awful calm succe$s1 sudd5ly foll[$ by a r5ewal ( ! /orm 9 all its viol5ce1 b n[ bl[+ 9 a direction diametrically opposite to its =m] c\rse4 ,?is happ5$ at ! ,isl& ( ,/4 ,?omas on ! #bnd ( ,augu/1 #ahcg1 :]e ! hurricane increas$ 9 viol5ce till half-pa/ sev5 9 ! morn+1 :5 p]fect /illness took place = =ty m9utes1 aft] :i* ! /orm recomm5c$ 9 a contr>y direction4 ,! sudd5 fall ( ! m]cury 9 ! b>omet] 9 ! regions habitually visit$ by hurricanes is a c]ta9 indication ( a com+ tempe/4 ,9 consequ5ce ( ! c5trifugal =ce ( ^! rotatory /orms ! air becomes r>efi$1 &1 z ! atmosph]e is di/urb$ to "s di/ance beyond ! actual circle ( gyration or limits ( ! /orm1 ! b>omet] (t5 s9ks "s h\rs be=e its arrival1 f ! orig9al cause ( ! rotatory di/urbance4 ,x cont9ues s9k+ "u ! fir/ half ( ! hurricane1 is at a maximum sometimes ( two in*es 9 ! c5tre ( gyration1 & aga9 rises dur+ ! passage ( ! latt] half1 ?\gh x does n atta9 its greate/ height till ! /orm is ov]4 ,! dim9ution ( atmosph]ic pressure is great] & ext5ds ov] a wid] area 9 ! temp]ate zones ?an 9 ! torrid1 on acc\nt ( ! sudd5 expansion ( ! circle ( rotation :5 ! gale crosses ! tropic4 ,z ! fall ( ! b>omet] gives w>n+ ( ! approa* ( a hurricane1 s ! laws ( ! /orm's motion af=d ! seaman k to guide him 9 avoid+ x4 ,9 ! nor!rn temp]ate zone1 if ! gale beg9s f ! ,s4,e4 & ve]s by ,s4 to ,w41 ! %ip %\ld /e] to ! ,s4,e42 b1 if ! gale beg9s f ! ,n4,e41 & *anges ?r\gh ,n4 to ,n4,w41 ! vessel %\ld g to ! ,n4,w4 ,9 ! nor!rn "p ( ! torrid zone1 if ! /orm beg9 f ! ,n4,e41 & ve] ?r\gh ,e4 to ,s4,e41 ! %ip %\ld /e] to ! ,n4,e42 b1 if x beg9 f ! ,n4,w41 & ve] by ,w4 to ,s4,w41 ! %ip %\ld /e] to ! ,s4,w41 because %e is 9 ! s\?-we/]n side ( ! /orm4 ,s9ce ! laws ( /orms are rev]s$ 9 ! s\!rn hemisph]e1 ! rules = /e]+ vessels are necess>ily rev]s$ also4 ,a heavy swell is peculi>ly *>act]i/ic ( ^! /orms4 ,9 ! op5 sea ! swell (t5 ext5ds _m leagues beyond ! range ( ! gale :i* produc$ x4 ,wat]sp\ts are occasion$ by small :irlw9ds1 :i* always h _! orig9 at a great di/ance f t "p ( ! sea f :i* ! sp\t beg9s to rise1 :]e x is g5]ally calm4 ,! :irl is produc$ by two curr5ts ( air1 :i*1 runn+ 9 opposite directions1 compress "o ano!r by _! impetus1 s t !y rise 9 spiral eddies to ! cl\ds4 ,!y move sl[ly along ! surface ( ! sea1 sometimes 9 v]tical1 & sometimes 9 twi/$ spirals1 putt+ ! sea into viol5t agitation z !y pass1 & c>ry+ ! wat] al(t by ! =ce ( gyration4 ,occasionally ! eddies beg9 9 ! cl\ds & dip d[n to ! sea4 ,,section ,,xvi4 ,s\nd--,propagation ( ,s\nd illu/rat$ by a ,field ( ,/&+ ,corn--,nature ( ,waves--,propagation ( ,s\nd ?r\gh ! ,atmosph]e--,int5sity--,noises--,a ,musical ,s\nd--,quality--,pit*--,ext5t ( ,human ,he>+--,velocity ( ,s\nd 9 ,air1 ,wat]1 & ,solids--,causes ( ! ,ob/ruction ( ,s\nd--,law ( its ,int5sity--,reflection ( ,s\nd--,e*oes--,?und]--,refraction ( ,s\nd--,int]f]5ce ( ,s\nds4 ,,"o ( ! mo/ important uses ( ! atmosph]e is ! conveyance ( s\nd4 ,)\t ! air1 dea?like sil5ce w\ld prevail ?r\gh nature1 = 9 common ) all sub/ances x has a t5d5cy to imp>t vibrations to bodies 9 contact ) x4 ,!re=e undulations receiv$ by ! air1 :e!r x be f a sudd5 impulse1 su* z an explosion or ! vibrations ( a musical *ord1 are propagat$ 9 e direction1 & produce ! s5sation ( s\nd ^u ! auditory n]ves4 ,a bell rung "u ! exhau/$ receiv] ( an air-pump is inaudible1 :i* %[s t ! atmosph]e is really ! m$ium ( s\nd4 ,9 ! small undulations ( deep wat] 9 a calm1 ! vibrations ( ! liquid p>ticles are made 9 ! v]tical plane1 t is1 up & d[n1 or at "r angles to ! direction ( ! transmission ( ! waves4 ,b ! vibrations ( ! p>ticles ( air :i* produce s\nd diff] f ^!1 be+ p]=m$ 9 ! same direction 9 :i* ! waves ( s\nd travel4 ,! propagation ( s\nd has be5 illu/rat$ by a field ( corn agitat$ by ! w9d4 ,h[ev] irregul> ! motion ( ! corn may seem on a sup]ficial view1 x w be f\nd1 if ! velocity ( ! w9d be con/ant1 t ! waves are all precisely simil> & equal1 & t all are sep>at$ by equal int]vals & move 9 equal times4 ,a sudd5 bla/ depresses ea* e> equally & successively 9 ! direction ( ! w9d1 b1 9 consequ5ce ( ! ela/icity ( ! /alks & ! =ce ( ! impulse1 ea* e> n only rises aga9 z soon z ! pressure is remov$1 b b5ds back ne>ly z mu* 9 ! contr>y direction1 & !n cont9ues to oscillate backw>ds & =w>ds 9 equal times1 l a p5dulum1 to a less & less ext5t1 till ! resi/ance ( ! air puts a /op to ! motion4 ,^! vibrations are ! same = e individual e> ( corn4 ,yet1 z _! oscillations d n all comm5ce at ! same "t1 b successively1 ! e>s w h a v>iety ( positions at any "o in/ant4 ,"s ( ! advanc+ e>s w meet o!rs 9 _! return+ vibrations1 &1 z ! times ( oscillation are equal = all1 !y w be cr[d$ toge!r at regul> int]vals4 ,betwe5 ^! !re w occur equal spaces :]e ! e>s w be few1 9 consequ5ce ( be+ b5t 9 opposite directions2 & at o!r equal int]vals !y w be 9 _! natural upright positions4 ,s t ov] ! :ole field !re w be a regul> s]ies ( cond5sations & r>efactions among ! e>s ( corn1 sep>at$ by equal int]vals1 :]e !y w be 9 _! natural /ate ( d5sity4 ,9 consequ5ce ( ^! *anges ! field w be m>k$ by an alt]nation ( bright & d>k b&s4 ,?us ! successive waves :i* fly ov] ! corn ) ! spe$ ( ! w9d are totally di/9ct f1 & entirely indep5d5t ( ! ext5t ( ! oscillations ( ea* individual e>1 ?\gh bo? take place 9 ! same direction4 ,! l5g? ( a wave is equal to ! space betwe5 two e>s precisely 9 ! same /ate ( motion1 or :i* are mov+ simil>ly1 & ! "t ( ! vibration ( ea* e> is equal to t :i* elapses betwe5 ! arrival ( two successive waves at ! same po9t4 ,! only diff]5ce betwe5 ! undulations ( a corn-field & ^? ( ! air :i* produce s\nd is1 t ea* e> ( corn is set 9 motion by an ext]nal cause1 & is un9flu5c$ by ! motion ( ! re/2 :]eas 9 air1 :i* is a compressible & ela/ic fluid1 :5 "o p>ticle beg9s to oscillate1 x communicates its vibrations to ! surr\nd+ p>ticles1 :i* transmit !m to ^? adjac5t1 & s on cont9ually4 ,h5ce f ! successive vibrations ( ! p>ticles ( air ! same regul> cond5sations & r>efactions take place z 9 ! field ( corn1 produc+ waves ?r\gh\t ! :ole mass ( air1 ?\gh ea* molecule l ea* individual e> ( corn nev] moves f> f its /ate ( re/4 ,! small waves ( a liquid1 & ! undulations ( ! air1 l waves 9 ! corn1 are evid5tly n real masses mov+ 9 ! direction 9 :i* !y are advanc+1 b m]ely outl9es1 motions1 or =ms pass+ along1 & compreh5d+ all ! p>ticles ( an undulat+ fluid :i* are at once 9 a vibratory /ate4 ,x is ?us t an impulse giv5 to any "o po9t ( ! atmosph]e is successively propagat$ 9 all directions1 9 a wave div]g+ z f ! c5tre ( a sph]e to great] & great] di/ances1 b ) decreas+ int5sity1 9 consequ5ce ( ! increas+ numb] ( p>ticles ( in]t matt] :i* ! =ce has to move2 l ! waves =m$ 9 /ill wat] by a fall+ /one1 :i* are propagat$ circul>ly all ar\nd ! c5tre ( di/urbance 7,n4 #afj74 ,! int5sity ( s\nd dep5ds ^u ! viol5ce & ext5t ( ! initial vibrations ( air2 b1 :atev] !y may be1 ea* undulation :5 once =m$ c only be transmitt$ /raight =w>ds1 & nev] returns back aga9 unless :5 reflect$ by an oppos+ ob/acle4 ,! vibrations ( ! arial molecules are always extremely small1 :]eas ! waves ( s\nd v>y f a few in*es to sev]al feet4 ,! v>i\s musical in/rum5ts1 ! human voice & t ( animals1 ! s++ ( birds1 ! hum ( insects1 ! ro> ( ! cat>act1 ! :i/l+ ( ! w9d1 & ! o!r nameless peculi>ities ( s\nd1 %[ at once an inf9ite v>iety 9 ! modes ( arial vibration1 & ! a/oni%+ acut5ess & delicacy ( ! e>1 ?us capable ( appreciat+ ! m9ute/ diff]5ces 9 ! laws ( molecul> oscillation4 ,all m]e noises are occasion$ by irregul> impulses communicat$ to ! e>2 &1 if !y be %ort1 sudd51 & repeat$ beyond a c]ta9 degree ( quickness1 ! e> loses ! int]vals ( sil5ce1 & ! s\nd appe>s cont9u\s4 ,/ill su* s\nds w be m]e noise3 9 ord] to produce a musical s\nd1 ! impulses1 & consequ5tly ! undulations ( ! air1 mu/ be all exactly simil> 9 duration & int5sity1 & mu/ recur aft] exactly equal int]vals ( "t4 ,if a bl[ be giv5 to ! ne>e/ ( a s]ies ( broad1 flat1 & equidi/ant palisades1 set edgewise 9 a l9e direct f ! e>1 ea* palisade w repeat or e*o ! s\nd2 & ^! e*oes1 return+ to ! e> at successive equal int]vals ( "t1 w produce a musical note4 ,! quality ( a musical note dep5ds ^u ! abruptness1 & its int5sity ^u ! viol5ce & ext5t ( ! orig9al impulse4 ,9 ! !ory ( h>mony ! only prop]ty ( s\nd tak5 into consid]ation is ! pit*1 :i* v>ies ) ! rapidity ( ! vibrations4 ,! grave or l[ tones are produc$ by v sl[ vibrations1 :i* increase 9 frequ5cy z ! note becomes m acute4 ,! l[e/ man's voice makes #cif vibrations 9 a second1 :il/ ! highe/ woman's voice makes #baab4 ,v deep tones are n he>d by all alike1 & ,dr4 ,wolla/on1 :o made a v>iety ( exp]im5ts on ! s5se ( he>+1 f\nd t _m p1 ?\gh n at all deaf1 are q ins5sible to ! cry ( ! bat or ! cricket1 :ile to o!rs x is pa9fully %rill4 ,f 8 exp]im5ts he conclud$ t human he>+ is limit$ to ab\t n9e octaves1 ext5d+ f ! l[e/ note ( ! organ to ! highe/ kn[n cry ( insects2 & he obs]ves ) 8 usual orig9ality t1 8z !re is no?+ 9 ! nature ( ! atmosph]e to prev5t ! exi/5ce ( vibrations incomp>ably m frequ5t ?an any ( :i* we are consci\s1 we may imag9e t animals l ! ,grylli1 ^: p[]s appe> to comm5ce ne>ly :]e ours t]m9ate1 may h ! faculty ( he>+ /ill %>p] s\nds :i* we d n "k to exi/1 & t !re may be o!r insects he>+ no?+ 9 common ) u1 b end[$ ) a p[] ( excit+1 & a s5se :i* p]ceives vibrations1 ( ! same nature inde$ z ^? :i* con/itute our ord9>y s\nds1 b s remote t ! animals :i* p]ceive !m may be said to possess ano!r s5se1 agree+ ) our own solely 9 ! m$ium by :i* x is excit$40 ,m4 ,sav>t1 s well kn[n = ! numb] & beauty ( 8 rese>*es 9 ac\/ics1 has prov$ t a high note ( a giv5 int5sity1 be+ he>d by "s e>s & n by o!rs1 mu/ n be attribut$ to its pit*1 b to its feebl5ess4 ,8 exp]im5ts1 & ^? m rec5tly made by ,pr(essor ,:eat/one1 %[ t1 if ! pulses c\ld be r5d]$ suffici5tly p[]ful1 x w\ld be difficult to fix a limit to human he>+ at ei!r end ( ! scale4 ,m4 ,sav>t _h a :eel made ab\t n9e in*es 9 diamet] ) #cfj tee? set at equal di/ances r\nd its rim1 s t :ile 9 motion ea* too? successively hit on a piece ( c>d4 ,! tone increas$ 9 pit* ) ! rapidity ( ! rotation1 & 0 v pure :5 ! numb] ( /rokes did n exce$ ?ree or f\r ?\s& 9 a second1 b beyond t x became feeble & indi/9ct4 ,) a :eel ( a l>g] size a mu* high] tone c\ld be obta9$1 because1 ! tee? be+ wid] ap>t1 ! bl[s 7 m int5se & m sep>at$ f "o ano!r4 ,) #gbj tee? on a :eel ?irty-two in*es 9 diamet]1 ! s\nd produc$ by #ab1jjj /rokes 9 a second 0 audible1 :i* corresponds to #bd1jjj vibrations ( a musical *ord4 ,s t ! human e> c appreciate a s\nd :i* only la/s ! #bd1jjj? "p ( a second4 ,?is note 0 di/9ctly he>d by ,m4 ,sav>t & by sev]al p :o 7 pres5t1 :i* conv9c$ him t ) ano!r app>atus /ill m acute s\nds might be r5d]$ audible4 ,= ! deep tones ,m4 ,sav>t employ$ a b> ( iron1 two feet eight in*es long1 ab\t two in*es broad1 & half an in* 9 ?ickness1 :i* revolv$ ab\t its c5tre z if its arms 7 ! spokes ( a :eel4 ,:5 su* a ma*9e rotates1 x impresses a motion on ! air simil> to its own1 &1 :5 a ?9 bo>d or c>d is br\ght close to its extremities1 ! curr5t ( air is mom5t>ily int]rupt$ at ! in/ant ea* arm ( ! b> passes be=e ! c>d2 x is compress$ above ! c>d & dilat$ bel[2 b ! in/ant ! spoke has pass$ a ru% ( air to re/ore equilibrium makes a k9d ( explosion1 &1 :5 ^! succe$ ea* o!r rapidly1 a musical note is produc$ ( a pit* proportional to ! velocity ( ! revolution4 ,:5 ,m4 ,sav>t turn$ ?is b> sl[ly1 a succession ( s+le beats 0 he>d2 z ! velocity became great]1 ! s\nd 0 only a rattle2 b1 z soon z x 0 suffici5t to give eight beats 9 a second1 a v deep musical note 0 di/9ctly audible correspond+ to sixte5 s+le vibrations 9 a second1 :i* is ! l[e/ t has hi!rto be5 produc$4 ,:5 ! velocity ( ! b> 0 mu* increas$1 ! int5sity ( ! s\nd 0 h>dly be>able4 ,! spokes ( a revolv+ :eel produce ! s5sation ( s\nd1 on ! v same pr9ciple t a burn+ /ick :irl$ r\nd gives ! impression ( a lum9\s circle4 ,! vibrations excit$ 9 ! organ ( he>+ by "o beat h n ceas$ be=e ano!r impulse is giv54 ,inde$ x is indisp5sable t ! impressions made ^u ! auditory n]ves %\ld encroa* ^u ea* o!r 9 ord] to produce a full & cont9u$ note4 ,on ! :ole1 ,m4 ,sav>t has come to ! conclusion1 t ! mo/ acute s\nds w\ld be he>d ) z mu* ease z ^? ( a l[] pit*1 if ! duration ( ! s5sation produc$ by ea* pulse c\ld be dim9i%$ proportionally to ! augm5tation ( ! numb] ( pulses 9 a giv5 "t3 & on ! contr>y1 if ! duration ( ! s5sation produc$ by ea* pulse c\ld be increas$ 9 proportion to _! numb] 9 a giv5 "t1 t ! deepe/ tones w\ld be z audible z any ( ! o!rs4 ,! velocity ( s\nd is uni=m & indep5d5t ( ! nature1 ext5t1 & int5sity ( ! primitive di/urbance4 ,consequ5tly s\nds ( e quality & pit* travel ) equal spe$4 ,! smalle/ diff]5ce 9 _! velocity is incompatible ei!r ) h>mony or melody1 = notes ( diff]5t pit*es & int5sities1 s\nd$ toge!r at a little di/ance1 w\ld arrive at ! e> 9 diff]5t times4 ,a rapid succession ( notes w\ld 9 ?is case produce confusion & discord4 ,b1 z ! rapidity ) :i* s\nd is transmitt$ dep5ds ^u ! ela/icity ( ! m$ium ?r\gh :i* x has to pass1 :atev] t5ds to increase ! ela/icity ( ! air mu/ also accel]ate ! motion ( s\nd4 ,on t acc\nt its velocity is great] 9 w>m ?an 9 cold wea!r1 suppos+ ! pressure ( ! atmosph]e con/ant4 ,9 dry air1 at ! freez+ temp]ature1 s\nd travels at ! rate ( #ajij feet 9 a second1 & = any high] temp]ature "o foot mu/ be add$ = e degree ( ! !rmomet] above #cb3 h5ce at #fb ( ,fahr5heit its spe$ 9 a second is #aabj feet1 or #gfe miles an h\r1 :i* is ab\t ?ree-f\r?s ( ! diurnal velocity ( ! e>?'s equator4 ,s9ce all ! ph5om5a ( ! transmission ( s\nd are simple consequ5ces ( ! physical prop]ties ( ! air1 !y h be5 pr$ict$ & comput$ rigor\sly by ! laws ( me*anics4 ,x 0 f\nd1 h[ev]1 t ! velocity ( s\nd1 det]m9$ by obs]vation1 exce$$ :at x ought to h be5 !oretically by #agc feet1 or ab\t "o-six? ( ! :ole am\nt4 ,la ,place sugge/$ t ?is discrepancy might arise f ! increas$ ela/icity ( ! air 9 consequ5ce ( a developm5t ( lat5t or absorb$ heat 7,n4 #agh7 dur+ ! undulations ( s\nd1 & calculation confirm$ ! accuracy ( 8 views4 ,! arial molecules be+ sudd5ly compress$ give out _! absorb$ heat2 &1 z air is too bad a conductor to c>ry x rapidly (f1 x occasions a mom5t>y & local rise ( temp]ature1 :i*1 increas+ ! ela/icity ( ! air )\t at ! same "t increas+ its in]tia1 causes ! movem5t to be propagat$ m rapidly4 ,analysis gives ! true velocity ( s\nd 9 t]ms ( ! elevation ( temp]ature t a mass ( air is capable ( communicat+ to itself1 by ! dis5gagem5t ( its own absorb$ heat :5 sudd5ly compress$ 9 a giv5 ratio4 ,?is *ange ( temp]ature h[ev] c\ld n be obta9$ directly by any exp]im5ts :i* _h be5 made at t epo*2 b by inv]t+ ! problem1 & assum+ ! velocity ( s\nd z giv5 by exp]im5t1 x 0 comput$ t ! temp]ature ( a mass ( air is rais$ n9e-t5?s ( a degree :5 ! compression is equal to #a_/aaf ( its volume4 ,probably all liquids are ela/ic1 ?\gh consid]able =ce is requir$ to compress !m4 ,wat] suff]s a cond5sation ( ne>ly #jjjjjdif = e atmosph]e ( pressure1 & is consequ5tly capable ( convey+ s\nd ev5 m rapidly ?an air1 ! velocity 9 ! =m] be+ #dgjh feet 9 a second4 ,a p]son "u wat] he>s s\nds made 9 air feebly1 b ^? produc$ 9 wat] v di/9ctly4 ,accord+ to ! exp]im5ts ( ,m4 ,colladon1 ! s\nd ( a bell 0 convey$ "u wat] ?r\gh ! ,lake ( ,g5eva to ! di/ance ( ab\t n9e miles4 ,he also p]ceiv$ t ! progress ( s\nd ?r\gh wat] is greatly imp$$ by ! int]position ( any object1 su* z a project+ wall2 consequ5tly s\nd "u wat] resembles light 9 hav+ a di/9ct %ad[4 ,x has mu* less 9 air1 be+ transmitt$ all r\nd build+s or o!r ob/acles1 s z to be he>d 9 e direction1 ?\gh (t5 ) a consid]able dim9ution ( int5sity1 z :5 a c>riage turns ! corn] ( a /reet4 ,! velocity ( s\nd 9 pass+ ?r\gh solids is 9 proportion to _! h>dness1 & is mu* great] ?an 9 air or wat]4 ,a s\nd :i* takes "s "t 9 travell+ ?r\gh ! air passes almo/ in/antane\sly along a wire six hundr$ feet long2 consequ5tly x is he>d twice--fir/ z communicat$ by ! wire1 & aft]w>ds ?r\gh ! m$ium ( ! air4 ,! facility ) :i* ! vibrations ( s\nd are transmitt$ along ! gra9 ( a log ( wood is well kn[n4 ,inde$ !y pass ?r\gh iron1 glass1 & "s k9ds ( wood1 at ! rate ( #ah1ecj feet 9 a second4 ,! velocity ( s\nd is ob/ruct$ by a v>iety ( circum/ances1 su* z fall+ sn[1 fog1 ra91 or any o!r cause :i* di/urbs ! homog5eity ( ! m$ium ?r\gh :i* x has to pass4 ,m4 de ,humboldt says t x is on acc\nt ( ! great] homog5eity ( ! atmosph]e dur+ ! night t s\nds are !n bett] he>d ?an dur+ ! day1 :5 its d5sity is p]petually *ang+ f p>tial v>iations ( temp]ature4 ,8 att5tion 0 call$ to ?is subject on ! pla9 surr\nd+ ! ,mission ( ! ,apures by ! ru%+ noise ( ! great cat>acts ( ! ,or9oco1 :i* seem$ to be ?ree times z l\d by night z by day4 ,?is he illu/rat$ by exp]im5t4 ,a tall glass half full ( *ampagne _c be made to r+ z long z ! eff]vesc5ce la/s4 ,9 ord] to produce a musical note1 ! glass toge!r ) ! liquid x conta9s mu/ vibrate 9 unison z a sy/em1 :i* x _c d 9 consequ5ce ( ! fix$ air ris+ ?r\gh ! w9e & di/urb+ its homog5eity1 because1 ! vibrations ( ! gas be+ mu* sl[] ?an ^? ( ! liquid1 ! velocity ( ! s\nd is p]petually int]rupt$4 ,= ! same reason ! transmission ( s\nd z well z light is imp$$ 9 pass+ ?r\gh an atmosph]e ( v>iable d5sity4 ,sir ,john ,h]s*el1 9 8 admirable ,treatise on ,s\nd1 ?us expla9s ! ph5om5on3--8,x is obvi\s10 he says1 8t s\nd z well z light mu/ be ob/ruct$1 /ifl$1 & dissipat$ f its orig9al direction by ! mixture ( air ( diff]5t temp]atures1 & consequ5tly ela/icities2 & ?us ! same cause :i* produces t extreme transp>5cy ( ! air at night1 :i* a/ronom]s alone fully appreciate1 r5d]s x also m fav\rable to s\nd4 ,!re is no d\bt1 h[ev]1 t ! univ]sal & dead sil5ce g5]ally preval5t at night r5d]s our auditory n]ves s5sible to impressions :i* w\ld o!rwise escape notice4 ,! analogy betwe5 s\nd & light is p]fect 9 ?is z 9 s _m o!r respects4 ,9 ! g5]al light ( day ! />s disappe>4 ,9 ! cont9ual hum ( voices1 :i* is always go+ on by day1 & :i* rea* u f all qu>t]s1 & nev] leave ! e> "t to atta9 complete tranquillity1 ^? feeble s\nds :i* cat* our att5tion at night make no impression4 ,! e>1 l ! eye1 requires long & p]fect repose to atta9 its utmo/ s5sibility40 ,_m in/ances may be br\ght 9 pro( ( ! /r5g? & cle>ness ) :i* s\nd passes ov] ! surface ( wat] or ice4 ,lieut5ant ,=/] 0 able to c>ry on a conv]sation across ,port ,b[5 ,h>b\r1 :5 froz51 a di/ance ( a mile & a half4 ,! int5sity ( s\nd dep5ds ^u ! ext5t ( ! excursions ( ! fluid molecules1 on ! en]gy ( ! transi5t cond5sations & dilatations1 & on ! great] or less numb] ( p>ticles :i* exp]i5ce ^! effects4 ,we e/imate t int5sity by ! impetus ( ^! fluid molecules on our organs1 :i* is consequ5tly z ! squ>e ( ! velocity1 & n by _! in]tia1 :i* is z ! simple velocity4 ,7 ! latt] ! case1 !re w\ld be no s\nd1 because ! in]tia ( ! rec$+ waves ( air w\ld de/roy ! equal & opposite in]tia ( ^? advanc+2 :5ce x may be conclud$ t ! int5sity ( s\nd dim9i%es inv]sely z ! squ>e ( ! di/ance f its orig94 ,9 a tube1 h[ev]1 ! =ce ( s\nd does n decay z 9 op5 air1 unless p]haps by friction aga9/ ! sides4 ,m4 ,biot f\nd1 f a numb] ( highly-int]e/+ exp]im5ts made on ! pipes ( ! aqu$ucts 9 ,p>is1 t a cont9u$ conv]sation c\ld be c>ri$ on 9 ! l[e/ possible :isp] ?r\gh a cyl9drical tube ab\t #cabj feet long1 ! "t ( transmission ?r\gh t space be+ #bgi seconds4 ,9 mo/ cases s\nd div]ges 9 all directions s z to occupy at any "o "t a sph]ical surface2 b ,dr4 ,"y has %[n t !re are exceptions1 z1 = example1 :5 a flat surface vibrates only 9 "o direction4 ,! s\nd is !n mo/ int5se :5 ! e> is at "r angles to ! surface1 :]eas x is sc>cely audible 9 a direction precisely p]p5dicul> to its edge4 ,9 ?is case x is impossible t ! :ole ( ! surr\nd+ air c be affect$ 9 ! same mann]1 s9ce ! p>ticles beh9d ! s\nd+ surface mu/ be mov+ t[>ds x :5ev] ! p>ticles be=e x are retreat+4 ,h5ce 9 "o half ( ! surr\nd+ sph]e ( air its motions are retrograde1 :ile 9 ! o!r half !y are direct2 consequ5tly1 at ! edges :]e ^! two portions meet1 ! motions ( ! air w nei!r be retrograde nor direct1 & !re=e x mu/ be at re/4 ,x appe>s1 f !ory z well z daily exp]i5ce1 t s\nd is capable ( reflection f surfaces 7,n4 #agi7 accord+ to ! same laws z light4 ,inde$ any "o :o has obs]v$ ! reflection ( ! waves f a wall on ! side ( a riv]1 aft] ! passage ( a /eam-boat1 w h a p]fect idea ( ! reflection ( s\nd & ( light4 ,z e sub/ance 9 nature is m or less ela/ic1 x may be agitat$ accord+ to its own law by ! impulse ( a mass ( undulat+ air2 & reciprocally ! surface by its reaction w communicate its undulations back aga9 into ! air4 ,su* reflections produce e*oes2 & z a s]ies ( !m may take place betwe5 two or m ob/acles1 ea* w cause an e*o ( ! orig9al s\nd1 gr[+ fa9t] & fa9t] till x dies away2 because s\nd1 l light1 is weak5$ by reflection4 ,%\ld ! reflect+ surface be concave t[>ds a p]son1 ! s\nd w conv]ge t[>ds him ) increas$ int5sity1 :i* w be great] /ill if ! surface be sph]ical & conc5tric ) him4 ,undulations ( s\nd div]g+ f "o focus ( an elliptical %ell 7,n4 #ahj7 conv]ge 9 ! o!r aft] reflection4 ,consequ5tly a s\nd f ! "o w be he>d 9 ! o!r z if x 7 close to ! e>4 ,! roll+ noise ( ?und] has be5 attribut$ to rev]b]ation betwe5 diff]5t cl\ds1 :i* may possibly be ! case to a c]ta9 ext5t4 ,sir ,john ,h]s*el is ( op9ion t an int5sely prolong$ peal is probably ow+ to a comb9ation ( s\nds1 because1 ! velocity ( electricity be+ incomp>ably great] ?an t ( s\nd1 ! ?und] may be reg>d$ z orig9at+ 9 e po9t ( a fla% ( lightn+ at ! same in/ant4 ,! s\nd f ! ne>e/ po9t w arrive fir/2 & if ! fla% run 9 a direct l9e f a p]son1 ! noise w come lat] & lat] f ! remote po9ts ( its pa? 9 a cont9u$ ro>4 ,%\ld ! direction ( ! fla% be incl9$1 ! succession ( s\nds w be m rapid & int5se3 & if ! lightn+ describe a circul> curve r\nd a p]son1 ! s\nd w arrive f e po9t at ! same in/ant ) a /unn+ cra%4 ,9 l mann] ! subt]ranean noises he>d dur+ e>?quakes l di/ant ?und] may arise f ! consecutive arrival at ! e> ( undulations propagat$ at ! same in/ant f ne>] & m remote po9ts2 or if !y orig9ate 9 ! same po9t1 ! s\nd may come by diff]5t r\tes ?r\gh /rata ( diff]5t d5sities4 ,s\nds "u wat] are he>d v di/9ctly 9 ! air imm$iately above2 b ! int5sity decays ) great rapidity z ! obs]v] goes f>!r (f1 & is altoge!r inaudible at ! di/ance ( two or ?ree hundr$ y>ds4 ,s t waves ( s\nd1 l ^? ( light1 9 pass+ f a d5se to a r>e m$ium1 are n only refract$1 b suff] total reflection at v oblique incid5ces 7,n4 #ahi74 ,! laws ( int]f]5ce ext5d also to s\nd4 ,x is cle> t two equal & simil> musical /r+s w be 9 unison if !y communicate ! same numb] ( vibrations to ! air 9 ! same "t4 ,b if two su* /r+s be s ne>ly 9 unison t "o p]=ms a hundr$ vibrations 9 a second1 & ! o!r a hundr$ & "o 9 ! same p]iod--dur+ ! fir/ few vibrations ! two result+ s\nds w comb9e to =m "o ( d\ble ! int5sity ( ei!r1 because ! arial waves w s5sibly co9cide 9 "t & place2 b "o w gradually ga9 on ! o!r till at ! fiftie? vibration x w be half an oscillation 9 advance4 ,!n ! waves ( air :i* produce ! s\nd be+ s5sibly equal1 b ! rec$+ "p ( ! "o co9cid+ ) ! advanc+ "p ( ! o!r1 !y w de/roy "o ano!r1 & occasion an in/ant ( sil5ce4 ,! s\nd w be r5ew$ imm$iately aft]1 & w gradually increase till ! hundr$? vibration1 :5 ! two waves w comb9e to produce a s\nd d\ble ! int5sity ( ei!r4 ,^! int]vals ( sil5ce & greate/ int5sity1 call$ beats1 w recur e second2 b if ! notes diff] mu* f "o ano!r1 ! alt]nations w resemble a rattle2 & if ! /r+s be 9 p]fect unison1 !re w be no beats1 s9ce !re w be no int]f]5ce4 ,?us by int]f]5ce is meant ! co-exi/5ce ( two undulations 9 :i* ! l5g?s ( ! waves are ! same4 ,& z ! magnitude ( an undulation may be dim9i%$ by ! addition ( ano!r transmitt$ 9 ! same direction1 x foll[s t "o undulation may be absolutely de/roy$ by ano!r :5 waves ( ! same l5g? are transmitt$ 9 ! same direction1 provid$ t ! maxima ( ! undulations are equal1 & t "o foll[s ! o!r by half ! l5g? ( a wave4 ,a tun+-=k af=ds a good example ( int]f]5ce4 ,:5 t in/rum5t vibrates1 its two bran*es alt]nately rec$e f & approa* "o ano!r2 ea* communicates its vibrations to ! air1 & a musical note is ! consequ5ce4 ,if ! =k be held upright ab\t a foot f ! e>1 & turn$ r\nd its axis :ile vibrat+1 at e qu>t] revolution ! s\nd w sc>cely be he>d1 :ile at ! int]m$iate po9ts x w be /rong & cle>4 ,?is ph5om5on arises f ! int]f]5ce ( ! undulations ( air com+ f ! two bran*es ( ! =k4 ,:5 ! two bran*es co9cide1 or :5 !y are at equal di/ances f ! e>1 ! waves ( air comb9e to re9=ce ea* o!r2 b at ! quadrants1 :]e ! two bran*es are at unequal di/ances f ! e>1 ! l5g?s ( ! waves diff] by half an undulation1 & consequ5tly de/roy "o ano!r4 ,,section ,,xvii4 ,vibration ( ,musical ,/r+s--,h>monic ,s\nds--,nodes--,vibration ( ,air 9 ,w9d-,in/rum5ts--,vibration ( ,solids--,vibrat+ ,plates--,bells--,h>mony--,s\nd+ ,bo>ds--,=c$ ,vibrations--,resonance--,speak+ ,ma*9es4 ,,:5 ! p>ticles ( ela/ic bodies are sudd5ly di/urb$ by an impulse1 !y return to _! natural position by a s]ies ( iso*ron\s vibrations1 ^: rapidity1 =ce1 & p]man5cy dep5d ^u ! ela/icity1 ! =m1 & ! mode ( aggregation :i* unites ! p>ticles ( ! body4 ,^! oscillations are communicat$ to ! air1 & on acc\nt ( its ela/icity !y excite alt]nate cond5sations & dilatations 9 ! /rata ( ! fluid ne>e/ to ! vibrat+ body2 f !nce !y are propagat$ to a di/ance4 ,a /r+ or wire /ret*$ betwe5 two p9s1 :5 drawn aside & sudd5ly let g1 w vibrate till its own rigidity & ! resi/ance ( ! air r$uce x to re/4 ,^! oscillations may be rotatory1 9 e plane1 or conf9$ to "o plane accord+ z ! motion is communicat$4 ,9 ! piano-=te1 :]e ! /r+s are /ruck by a hamm] at "o extremity1 ! vibrations probably consi/ ( a bulge runn+ to & fro f end to end4 ,diff]5t modes ( vibration may be obta9$ f ! same sonor\s body4 ,suppose a vibrat+ /r+ to give ! l[e/ ,c ( ! pian(orte :i* is ! fundam5tal note ( ! /r+2 if x be lightly t\*$ exactly 9 ! middle1 s z to reta9 t po9t at re/1 ea* half w !n vibrate twice z fa/ z ! :ole1 b 9 opposite directions2 ! v5tral or bulg+ segm5ts w be alt]nately above & bel[ ! natural position ( ! /r+1 & ! result+ note w be ! octave above ,c4 ,:5 a po9t at a ?ird ( ! l5g? ( ! /r+ is kept at re/1 ! vibrations w be ?ree times z fa/ z ^? ( ! :ole /r+1 & w give ! twelf? above ,c4 ,:5 ! po9t ( re/ is "o-f\r? ( ! :ole1 ! oscillations w be f\r times z fa/ z ^? ( ! fundam5tal note1 & w give ! d\ble octave2 & s on4 ,^! acute s\nds are call$ ! h>monics ( ! fundam5tal note4 ,x is cle>1 f :at has be5 /at$1 t ! /r+ ?us vibrat+ c\ld n give ^! h>monics spontane\sly unless x divid$ itself at its aliquot p>ts into two1 ?ree1 f\r1 or m segm5ts 9 opposite /ates ( vibration sep>at$ by po9ts actually at re/4 ,9 pro( ( ?is1 pieces ( pap] plac$ on ! /r+ at ! half1 ?ird1 f\r?1 or o!r aliquot po9ts1 accord+ to ! correspond+ h>monic s\nd1 w rema9 on x dur+ its vibration1 b w in/antly fly (f f any ( ! int]m$iate po9ts4 ,! po9ts ( re/1 call$ ! nodal po9ts ( ! /r+1 are a m]e consequ5ce ( ! law ( int]f]5ces2 =1 if a rope fa/5$ at "o end be mov$ to & fro at ! o!r extremity s z to transmit a succession ( equal waves along x1 !y w be successively reflect$ :5 !y arrive at ! o!r end ( ! rope by ! fix$ po9t1 & 9 return+ !y w occasionally int]f]e ) ! advanc+ waves2 &1 z ^! opposite undulations w at c]ta9 po9ts de/roy "o ano!r1 ! po9t ( ! rope 9 :i* ?is happ5s w rema9 at re/4 ,?us a s]ies ( nodes & v5tral segm5ts w be produc$ ^: numb] w dep5d ^u ! t5sion & ! frequ5cy ( ! alt]nate motions communicat$ to ! moveable end4 ,s1 :5 a /r+ fix$ at bo? ends is put 9 motion by a sudd5 bl[ at any po9t ( x1 ! primitive impulse divides itself into two pulses runn+ opposite ways1 :i* are ea* totally reflect$ at ! extremities1 &1 runn+ back aga9 along ! :ole l5g?1 are aga9 reflect$ at ! o!r ends4 ,& ?us !y w cont9ue to run backw>ds & =w>ds1 cross+ "o ano!r at ea* trav]se1 & occasionally int]f]+1 s z to produce nodes2 s t ! motion ( a /r+ fa/5$ at bo? ends consi/s ( a wave or pulse cont9ually d\bl$ back on itself by reflection at ! fix$ extremities4 ,h>monics g5]ally co-exi/ ) ! fundam5tal s\nd 9 ! same vibrat+ body4 ,if "o ( ! l[e/ /r+s ( ! pian(orte be /ruck1 an att5tive e> w n only he> ! fundam5tal note1 b w detect all ! o!rs s\nd+ along ) x1 ?\gh ) less & less int5sity z _! pit* becomes high]4 ,accord+ to ! law ( co-exi/+ undulations1 ! :ole /r+ & ea* ( its aliquot p>ts are 9 diff]5t & indep5d5t /ates ( vibration at ! same "t2 & z all ! result+ notes are he>d simultane\sly1 n only ! air1 b ! e> also1 vibrates 9 unison ) ea* at ! same in/ant 7,n4 #aha74 ,h>mony consi/s 9 an agreeable comb9ation ( s\nds4 ,:5 two *ords p]=m _! vibrations 9 ! same "t1 !y are 9 unison2 b1 :5 _! vibrations are s relat$ z to h a common p]iod1 aft] a few oscillations !y produce concord4 ,?us1 :5 ! vibrations ( two /r+s be> a v simple relation to ea* o!r1 z :]e "o ( !m makes two1 ?ree1 f\r1 c41 vibrations 9 ! "t ! o!r makes "o2 or1 if x accompli%es ?ree1 f\r1 c41 vibrations :ile ! o!r makes two1 ! result is a concord :i* is ! m p]fect ! %ort] ! common p]iod4 ,9 discords1 on ! contr>y1 ! beats are di/9ctly audible1 :i* produces a disagreeable & h>% effect1 because ! vibrations d n be> a simple relation to "o ano!r1 z :]e "o ( two /r+s makes eight vibrations :ile ! o!r accompli%es fifte54 ,! pleasure af=d$ by h>mony is attribut$ by ,dr4 ,"y to ! love ( ord]1 & to a pr$ilection = a regul> repetition ( s5sations natural to ! human m9d1 :i* is gratifi$ by ! p]fect regul>ity & rapid recurr5ce ( ! vibrations4 ,! love ( poetry & danc+ he conceives to arise 9 "s degree f ! rhy?m ( ! "o & ! regul>ity ( ! motions 9 ! o!r4 ,a bla/ ( air pass+ ov] ! op5 end ( a tube1 z ov] ! re$s 9 ,pan's pipes2 ov] a hole 9 "o side1 z 9 ! flute2 or ?r\gh ! ap]ture call$ a re$1 ) a flexible tongue1 z 9 ! cl>9et1 puts ! int]nal column ( air into longitud9al vibrations by ! alt]nate cond5sations & r>efactions ( its p>ticles4 ,at ! same "t ! column spontane\sly divides itself into nodes1 betwe5 :i* ! air also vibrates longitud9ally1 b ) a rapidity inv]sely proportional to ! l5g? ( ! divisions1 giv+ ! fundam5tal note or "o ( its h>monics4 ,! nodes are produc$ on ! pr9ciple ( int]f]5ces by ! reflection ( ! longitud9al undulations ( ! air at ! ends ( ! pipe1 z 9 ! musical /r+1 only t 9 "o case ! undulations are longitud9al1 & 9 ! o!r transv]se4 ,a pipe1 ei!r op5 or %ut at bo? ends1 :5 s\nd$1 vibrates entire1 or divides itself spontane\sly into two1 ?ree1 f\r1 c41 segm5ts sep>at$ by nodes4 ,! :ole column gives ! fundam5tal note by waves or vibrations ( ! same l5g? ) ! pipe4 ,! fir/ h>monic is produc$ by waves half z long z ! tube1 ! second h>monic by waves a ?ird z long1 & s on4 ,! h>monic segm5ts 9 an op5 & %ut pipe are ! same 9 numb]1 b diff]5tly plac$4 ,9 a %ut pipe ! two ends are nodes1 b 9 an op5 pipe !re is half a segm5t at ea* extremity1 because ! air at ^! po9ts is nei!r r>efi$ nor cond5s$1 be+ 9 contact ) t :i* is ext]nal4 ,if "o ( ! ends ( ! op5 pipe be clos$1 its fundam5tal note w be an octave l[]3 ! air w n[ divide itself into ?ree1 five1 sev51 c41 segm5ts2 & ! wave produc+ its fundam5tal note w be twice z long z ! pipe1 s t x w be d\bl$ back 7,n4 #ahb74 ,all ^! notes may be produc$ sep>ately by v>y+ ! int5sity ( ! bla/4 ,bl[+ /eadily & g5tly1 ! fundam5tal note w s\nd2 :5 ! =ce ( ! bla/ is increas$ ! note w all at once />t up an octave2 :5 ! int5sity ( ! w9d is augm5t$ ! twelf? w be he>d2 &1 by cont9u+ to increase ! =ce ( ! bla/1 ! o!r h>monics may be obta9$1 b no =ce ( w9d w produce a note int]m$iate betwe5 ^!4 ,! h>monics ( a flute may be obta9$ 9 ?is mann]1 f ! l[e/ ,c or ,d upw>ds1 )\t alt]+ ! f+]+1 m]ely by increas+ ! int5sity ( ! bla/ & alt]+ ! =m ( ! lips4 ,pipes ( ! same dim5sions1 :e!r ( lead1 glass1 or wood1 give ! same tone z to pit* "u ! same circum/ances1 :i* %[s t ! air alone produces ! s\nd4 ,metal spr+s fa/5$ at "o end1 :5 =cibly b5t1 endeav\r to return to re/ by a s]ies ( vibrations1 :i* give v pleas+ tones1 z 9 musical boxes4 ,v>i\s musical in/rum5ts h be5 con/ruct$1 consi/+ ( metallic spr+s ?r[n into vibration by a curr5t ( air4 ,among ! mo/ p]fect ( ^! are ,mr4 ,:eat/one's ,symphonion1 ,conc]t9a1 & olian ,organ1 in/rum5ts ( diff]5t effects & capabilities1 b all possess+ consid]able execution & expression4 ,! ,syr5 is an +5i\s in/rum5t1 devis$ by ,m4 ,cagni>d de la ,t\r1 = asc]ta9+ ! numb] ( pulsations 9 a second1 correspond+ to ea* pit*3 ! notes are produc$ by jets ( air pass+ ?r\gh small ap]tures1 arrang$ at regul> di/ances 9 a circle on ! side ( a box1 be=e :i* a disc revolves pi]c$ ) ! same numb] ( holes4 ,dur+ a revolution ( ! disc ! curr5ts are alt]nately int]cept$ & all[$ to pass z _m times z !re are ap]tures 9 x1 & a s\nd is produc$ ^: pit* dep5ds on ! velocity ( rotation4 ,a glass or metallic rod1 :5 /ruck at "o end1 or rubb$ 9 ! direction ( its l5g? ) a wet f+]1 vibrates longitud9ally1 l a column ( air1 by ! alt]nate cond5sation & expansion ( its con/itu5t p>ticles1 produc+ a cle> & beautiful musical note ( a high pit*1 on acc\nt ( ! rapidity ) :i* ^! sub/ances transmit s\nd4 ,rods1 surfaces1 &1 9 g5]al1 all undulat+ bodies1 resolve !mselves into nodes4 ,b 9 surfaces ! p>ts :i* rema9 at re/ dur+ _! vibrations are l9es :i* are curv$ or plane accord+ to ! sub/ance1 its =m1 & ! mode ( vibration4 ,if a little f9e dry s& be /rew$ ov] ! surface ( a plate ( glass or metal1 & if undulations be excit$ by draw+ ! b[ ( a viol9 across its edge1 x w emit a musical s\nd1 & ! s& w imm$iately arrange itself 9 ! nodal l9es1 :]e alone x w accumulate & rema9 at re/1 because ! segm5ts ( ! surface on ea* side w be 9 diff]5t /ates ( vibration1 ! "o be+ elevat$ :ile ! o!r is depress$2 &1 z ^! two motions meet 9 ! nodal l9es1 !y neutralise "o ano!r4 ,^! l9es v>y 9 =m & position ) ! "p :]e ! b[ is drawn across1 & ! po9t by :i* ! plate is held4 ,! motion ( ! s& %[s 9 :at direction ! vibrations take place4 ,if !y be p]p5dicul> to ! surface1 ! s& w be viol5tly toss$ up & d[n till x f9ds ! po9ts ( re/4 ,if !y be tang5tial1 ! s& w only creep along ! surface to ! nodal l9es4 ,sometimes ! undulations are oblique1 or comp\nd$ ( bo? ! prec$+4 ,if a b[ be drawn across "o ( ! angles ( a squ>e plate ( glass or metal held firmly by ! c5tre1 ! s& w arrange itself 9 two /raight l9es p>allel to ! sides ( ! plate1 & cross+ 9 ! c5tre s z to divide x into f\r equal squ>es1 ^: motions w be contr>y to ea* o!r4 ,two ( ! diagonal squ>es w make _! excursions on "o side ( ! plate1 :ile ! o!r two make _! vibrations on ! o!r side ( x4 ,?is mode ( vibration produces ! l[e/ tone ( ! plate 7,n4 #ahc74 ,if ! plate be /ill held by ! c5tre1 & ! b[ appli$ to ! middle ( "o ( ! sides1 ! vibrations w be m rapid1 & ! tone w be a fif? high] ?an 9 ! prec$+ case3 n[ ! s& w arrange itself f corn] to corn]1 & w divide ! plate into f\r equal triangles1 ea* pair ( :i* w make _! excursions on opposite sides ( ! plate4 ,! nodal l9es & pit* v>y n only ) ! po9t :]e ! b[ is appli$1 b ) ! po9t by :i* ! plate is held1 :i* be+ at re/ necess>ily det]m9es ! direction ( "o ( ! quiesc5t l9es4 ,! =ms assum$ by ! s& 9 squ>e plates are v num]\s1 correspond+ to all ! v>i\s modes ( vibration4 ,! l9es 9 circul> plates are ev5 m rem>kable = _! symmetry1 & ^u !m ! =ms assum$ by ! s& may be class$ 9 ?ree sy/ems4 ,! fir/ is ! diametrical sy/em1 9 :i* ! figures consi/ ( diamet]s divid+ ! circumf]5ce ( ! plate into equal p>ts1 ea* ( :i* is 9 a diff]5t /ate ( vibration f ^? adjac5t4 ,two diamet]s1 = example1 cross+ at "r angles1 divide ! circumf]5ce into f\r equal p>ts2 ?ree diamet]s divide x into six equal p>ts2 f\r divide x into eight1 & s on4 ,9 a metallic plate1 ^! divisions may am\nt to ?irty-six or =ty4 ,! next is ! conc5tric sy/em1 :]e ! s& arranges itself 9 circles1 hav+ ! same c5tre ) ! plate2 & ! ?ird is ! comp\nd sy/em1 :]e ! figures assum$ by ! s& are comp\nd$ ( ! o!r two1 produc+ v complicat$ & beautiful =ms4 ,galileo seems to h be5 ! fir/ to notice ! po9ts ( re/ & motion 9 ! s\nd+-bo>d ( a musical in/rum5t2 b to ,*ladni is due ! :ole discov]y ( ! symmetrical =ms ( ! nodal l9es 9 vibrat+ plates 7,n4 #ahd74 ,pr(essor ,:eat/one has %[n1 9 a pap] read be=e ! ,royal ,society 9 #ahcc1 t all ,*ladni's figures1 & inde$ all ! nodal figures ( vibrat+ surfaces1 result f v simple modes ( vibration oscillat+ iso*ron\sly1 & sup]pos$ ^u ea* o!r2 ! result+ figure v>y+ ) ! compon5t modes ( vibration1 ! numb] ( ! sup]positions1 & ! angles at :i* !y are sup]pos$4 ,= example1 if a squ>e plate be vibrat+ s z to make ! s& arrange itself 9 /raight l9es p>allel to "o side ( ! plate1 & if1 9 addition to ?is1 su* vibrations be excit$ z w\ld h caus$ ! s& to =m 9 l9es p]p5dicul> to ! fir/ _h ! plate be5 at re/1 ! comb9$ vibrations w make ! s& =m 9 l9es f corn] to corn] 7,n4 #ahe74 ,m4 ,sav>t's exp]im5ts on ! vibrations ( flat glass rul]s are highly int]e/+4 ,let a lam9a ( glass #bg;9#ef long1 #jei ( an in* broad1 & #jjf ( an in* 9 ?ickness1 be held by ! edges 9 ! middle1 ) its flat surface horizontal4 ,if ?is surface be /rew$ ) s&1 & set 9 longitud9al vibration by rubb+ its "u surface ) a wet clo?1 ! s& on ! upp] surface w arrange itself 9 l9es p>allel to ! ends ( ! lam9a1 always 9 "o or o!r ( two sy/ems 7,n4 #ahf74 ,al?\gh ! same "o ( ! two sy/ems w always be produc$ by ! same plate ( glass1 yet among diff]5t plates ( ! prec$+ dim5sions1 ev5 ?\gh cut f ! same %eet side by side1 "o w inv>iably exhibit "o sy/em1 & ! o!r ! o!r1 )\t any visible reason = ! diff]5ce4 ,n[1 if ! positions ( ^! quiesc5t l9es be m>k$ on ! upp] surface1 & if ! plate be turn$ s t ! l[] surface becomes ! upp] "o1 ! s& be+ /rew$1 & vibrations excit$ z be=e1 ! nodal l9es w /ill be p>allel to ! ends ( ! lam9a1 b _! positions w be int]m$iate betwe5 ^? ( ! upp] surface 7,n4 #ahg74 ,?us x appe>s t all ! motions ( "o half ( ! ?ickness ( ! lam9a1 or rul]1 are exactly contr>y to ^? ( ! correspond+ po9ts ( ! o!r half4 ,if ! ?ickness ( ! lam9a be increas$1 ! o!r dim5sions rema9+ ! same1 ! s\nd w n v>y1 b ! numb] ( nodal l9es w be less4 ,:5 ! bread? ( ! lam9a exce$s ! #jf ( an in*1 ! nodal l9es become curv$1 & are diff]5t on ! two surfaces4 ,a great v>iety ( =ms are produc$ by increas+ ! bread? & *ang+ ! =m ( ! surface2 b 9 all x appe>s t ! motions 9 "o half ( ! ?ickness are oppos$ to ^? 9 ! o!r half4 ,m4 ,sav>t also f\nd1 by plac+ small pap] r+s r\nd a cyl9drical tube or rod1 s z to re/ ^u x at "o po9t only1 t1 :5 ! tube or rod is cont9ually turn$ on its axis 9 ! same direction1 ! r+s slide along dur+ ! vibrations1 till !y come to a quiesc5t po9t1 :]e !y re/4 ,by trac+ ^! nodal l9es he discov]$ t !y twi/ 9 a spiral or corkscrew r\nd rods & cyl9d]s1 mak+ "o or m turns accord+ to ! l5g?2 b at c]ta9 po9ts1 v>y+ 9 numb] accord+ to ! mode ( vibration ( ! rod1 ! screw /ops1 & recomm5ces on ! o!r side1 ?\gh x is turn$ 9 a contr>y direction2 t is1 on "o side x is a "r-h&$ screw1 on ! o!r a left 7,n4 #ahh74 ,! nodal l9es 9 ! int]ior surface ( ! tube are p]fectly simil> to ^? 9 ! ext]ior1 b !y occupy int]m$iate positions4 ,if a small ivory ball be put )9 ! tube1 x w foll[ ^! nodal l9es :5 ! tube is made to revolve on its axis4 ,all solids :i* r+ :5 /ruck1 su* z bells1 dr9k+ glasses1 gongs1 c41 h _! %ape mom5t>ily & =cibly *ang$ by ! bl[1 & f _! ela/icity1 or t5d5cy to resume _! natural =m1 a s]ies ( undulations take place1 ow+ to ! alt]nate cond5sations & r>efactions ( ! p>ticles ( solid matt]4 ,^! h also _! h>monic tones1 & consequ5tly nodes4 ,inde$1 g5]ally1 :5 a rigid sy/em ( any =m :atev] vibrates ei!r transv]sely or longitud9ally1 x divides itself into a c]ta9 numb] ( p>ts :i* p]=m _! vibrations )\t di/urb+ "o ano!r4 ,^! p>ts are at e in/ant 9 alt]nate /ates ( undulation2 &1 z ! po9ts or l9es :]e !y jo9 p>take ( bo?1 !y rema9 at re/1 because ! oppos+ motions de/roy "o ano!r4 ,! air1 not)/&+ its r>ity1 is capable ( transmitt+ its undulations :5 9 contact ) a body susceptible ( admitt+ & excit+ !m4 ,x is ?us t sympa!tic undulations are excit$ by a body vibrat+ ne> insulat$ t5d$ /r+s1 capable ( foll[+ its undulations1 ei!r by vibrat+ entire1 or by sep>at+ !mselves into _! h>monic divisions4 ,if two *ords equally /ret*$1 ( :i* "o is twice or ?ree times long] ?an ! o!r1 be plac$ side by side1 & if ! %ort] be s\nd$1 its vibrations w be communicat$ by ! air to ! o!r1 :i* w be ?r[n into su* a /ate ( vibration t x w be spontane\sly divid$ into segm5ts equal 9 l5g? to ! %ort] /r+4 ,:5 a tun+-=k receives a bl[ & is made to re/ ^u a piano-=te dur+ its vibration1 e /r+ :i*1 ei!r by its natural l5g? or by its spontane\s subdivisions1 is capable ( execut+ correspond+ vibrations1 responds 9 a sympa!tic note4 ,! same effect w be produc$ by ! /roke ( a bell ne> a piano or h>p4 ,"s "o or o!r ( ! notes ( an organ are g5]ally 9 unison ) "o ( ! panes or ) ! :ole sa% ( a w9d[1 :i* consequ5tly res\nds :5 ^? notes are s\nd$4 ,a peal ( ?und] has frequ5tly ! same effect4 ,! s\nd ( v l>ge organ-pipes is g5]ally inaudible till ! air be set 9 motion by ! undulations ( "s ( ! sup]ior accords1 & !n ! s\nd becomes extremely en]getic4 ,recurr+ vibrations occasionally influ5ce ea* o!r's p]iods4 ,= example1 two adjac5t organ-pipes ne>ly 9 unison may =ce !mselves into concord2 & two clocks1 ^: rates diff]$ consid]ably :5 sep>ate1 h be5 kn[n to beat toge!r :5 fix$ to ! same wall1 & "o clock has =c$ ! p5dulum ( ano!r into motion1 :5 m]ely /&+ on ! same /one pavem5t4 ,^! =c$ oscillations1 :i* correspond 9 _! p]iods ) ^? ( ! excit+ cause1 are to be trac$ 9 e dep>tm5t ( physical sci5ce4 ,sev]al in/ances ( !m h already occurr$ 9 ?is "w4 ,su* are ! tides1 :i* foll[ ! sun & moon 9 all _! motions & p]iods4 ,! nutation ( ! e>?'s axis also1 :i* corresponds ) ! p]iod1 & repres5ts ! motion ( ! nodes ( ! moon1 is aga9 reflect$ back to ! moon1 & may be trac$ 9 ! nutation ( ! lun> orbit4 ,&1 la/ly1 ! accel]ation ( ! moon's mean motion repres5ts ! action ( ! planets on ! e>? reflect$ by ! sun to ! moon4 ,9 consequ5ce ( ! facility ) :i* ! air communicates undulations1 all ! ph5om5a ( vibrat+ plates may be exhibit$ by s& /rew$ on pap] or p>*m5t1 /ret*$ ov] a h>monica glass or l>ge bell-%ap$ tumbl]4 ,9 ord] to give due t5sion to ! pap] or vellum1 x mu/ be wett$1 /ret*$ ov] ! glass1 gumm$ r\nd ! edges1 all[$ to dry1 & v>ni%$ ov]1 to prev5t *anges 9 its t5sion f ! humidity ( ! atmosph]e4 ,if a circul> disc ( glass be held conc5trically ov] ?is app>atus1 ) its plane p>allel to ! surface ( ! pap]1 & set 9 vibration by draw+ a b[ across its edge1 s z to make s& on its surface take any ( ,*ladni's figures1 ! s& on ! pap] w assume ! v same =m1 9 consequ5ce ( ! vibrations ( ! disc be+ communicat$ to ! pap] by ! air4 ,:5 ! disc is remov$ sl[ly 9 a horizontal direction1 ! =ms on ! pap] w correspond ) ^? on ! disc1 till ! di/ance is too great = ! air to convey ! vibrations4 ,if ! disc :ile vibrat+ be gradually m & m incl9$ to ! horizon1 ! figures on ! pap] w v>y by degrees2 &1 :5 ! vibrat+ disc is p]p5dicul> to ! horizon1 ! s& on ! pap] w =m into /raight l9es p>allel to ! surface ( ! disc1 by creep+ along x in/ead ( danc+ up & d[n4 ,if ! disc be made to turn r\nd its v]tical diamet] :ile vibrat+1 ! nodal l9es on ! pap] w revolve1 & exactly foll[ ! motion ( ! disc4 ,x appe>s1 f ?is exp]im5t1 t ! motions ( ! arial molecules 9 e "p ( a sph]ical wave1 propagat$ f a vibrat+ body z a c5tre1 are p>allel to ea* o!r1 & n div]g5t l ! radii ( a circle4 ,:5 a sl[ air is play$ on a flute ne> ?is app>atus1 ea* note calls up a p>ticul> =m 9 ! s&1 :i* ! next note effaces1 to e/abli% its own4 ,! motion ( ! s& w ev5 detect s\nds t are inaudible4 ,by ! vibrations ( s& on a drum-head ! besieg$ h discov]$ ! direction 9 :i* a c\nt]-m9e 0 work+4 ,m4 ,sav>t1 :o made ^! beautiful exp]im5ts1 employ$ ?is app>atus to discov] nodal l9es 9 masses ( air4 ,he f\nd t ! air ( a room1 :5 ?r[n into undulations by ! cont9u$ s\nd ( an organ-pipe1 or by any o!r means1 divides itself into masses sep>at$ by nodal curves ( d\ble curvature1 su* z spirals1 on ea* side ( :i* ! air is 9 opposite /ates ( vibration4 ,he ev5 trac$ ^! quiesc5t l9es go+ out at an op5 w9d[1 & = a consid]able di/ance 9 ! op5 air4 ,! s& is viol5tly agitat$ :]e ! undulations ( ! air are greate/1 & rema9s at re/ 9 ! nodal l9es4 ,m4 ,sav>t obs]v$1 t :5 he mov$ 8 head away f a quiesc5t l9e t[>ds ! "r ! s\nd appe>$ to come f ! "r1 & :5 he mov$ x t[>ds ! left ! s\nd seem$ to come f ! left1 because ! molecules ( air are 9 diff]5t /ates ( motion on ea* side ( ! quiesc5t l9e4 ,a musical /r+ gives a v feeble s\nd :5 vibrat+ alone1 on acc\nt ( ! small quantity ( air set 9 motion2 b :5 atta*$ to a s\nd+-bo>d1 z 9 ! h>p & piano-=te1 x communicates its undulations to t surface1 & f !nce to e "p ( ! in/rum5t2 s t ! :ole sy/em vibrates iso*ron\sly1 & by expos+ an ext5sive undulat+ surface1 :i* transmits its undulations to a great mass ( air1 ! s\nd is mu* re9=c$4 ,! int5sity is greate/ :5 ! vibrations ( ! /r+ or s\nd+ body are p]p5dicul> to ! s\nd+-bo>d1 & lea/ :5 !y are 9 ! same plane ) x4 ,! s\nd+-bo>d ( ! piano-=te is bett] dispos$ ?an t ( any o!r /r+$ in/rum5t1 because ! hamm]s /rike ! /r+s s z to make !m vibrate at "r angles to x4 ,9 ! guit>1 on ! contr>y1 !y are /ruck obliquely1 :i* r5d]s ! tone feeble1 unless :5 ! sides1 :i* also act z a s\nd+-bo>d1 are deep4 ,x is evid5t t ! s\nd+-bo>d & ! :ole in/rum5t are agitat$ at once by all ! sup]pos$ vibrations excit$ by ! simultane\s or consecutive notes t are s\nd$1 ea* hav+ its p]fect effect indep5d5tly ( ! re/4 ,a s\nd+-bo>d n only reciprocates ! diff]5t degrees ( pit*1 b all ! nameless qualities ( tone4 ,?is has be5 beautifully illu/rat$ by ,pr(essor ,:eat/one 9 a s]ies ( exp]im5ts on ! transmission ?r\gh solid conductors ( musical p]=mances1 f ! h>p1 piano1 viol91 cl>9et1 c4 ,he f\nd t all ! v>ieties ( pit*1 quality1 & int5sity are p]fectly transmitt$ ) _! relative gradations1 & may be communicat$1 ?r\gh conduct+ wires or rods ( v consid]able l5g?1 to a prop]ly dispos$ s\nd+-bo>d 9 a di/ant ap>tm5t4 ,! s\nds ( an entire or*e/ra may be transmitt$ & reciprocat$ by connect+ "o end ( a metallic rod ) a s\nd+-bo>d ne> ! or*e/ra1 s plac$ z to res\nd to all ! in/rum5ts1 & ! o!r end ) ! s\nd+-bo>d ( a h>p1 piano1 or guit>1 9 a remote ap>tm5t4 ,pr(essor ,:eat/one obs]ves1 8,! effect ( ?is exp]im5t is v pleas+2 ! s\nds1 inde$1 h s little int5sity z sc>cely to be he>d at a di/ance f ! reciprocat+ in/rum5t2 b1 on plac+ ! e> close to x1 a dim9utive b& is he>d 9 :i* all ! in/rum5ts pres]ve _! di/9ctive qualities1 & ! pianos & =tes1 ! cresc5dos & dim9u5dos1 _! relative contra/s4 ,comp>$ ) an ord9>y b& he>d at a di/ance ?r\gh ! air1 ! effect is z a l&scape se5 9 m9iature beauty ?r\gh a concave l5s1 comp>$ ) ! same sc5e view$ by ord9>y vision ?r\gh a murky atmosph]e40 ,e "o is aw>e ( ! re9=cem5t ( s\nd by ! resonance ( cavities4 ,:5 s++ or speak+ ne> ! ap]ture ( a wide-m\!d vessel1 ! int5sity ( "s "o note 9 unison ) ! air 9 ! cavity is (t5 augm5t$ to a great degree4 ,any vessel w res\nd if a body vibrat+ ! natural note ( ! cavity be plac$ opposite to its orifice1 & be l>ge en\gh to cov] x1 or at lea/ to set a l>ge portion ( ! adjac5t air 9 motion4 ,= ! s\nd w be alt]nately reflect$ by ! bottom ( ! cavity & ! undulat+ body at its m\?4 ,! fir/ impulse ( ! undulat+ sub/ance w be reflect$ by ! bottom ( ! cavity1 & !n by ! undulat+ body1 9 "t to comb9e ) ! second new impulse4 ,?is re9=c$ s\nd w also be twice reflect$ 9 "t to conspire ) ! ?ird new impulse2 &1 z ! same process w be repeat$ on e new impulse1 ea* w comb9e ) all its e*oes to re9=ce ! s\nd prodigi\sly4 ,pr(essor ,:eat/one1 to ^: +5uity we are indebt$ = s mu* new & valuable in=mation on ! !ory ( s\nd1 has giv5 "s v /rik+ in/ances ( resonance4 ,if "o ( ! bran*es ( a vibrat+ tun+-=k be br\ght ne> ! emb\*ure ( a flute1 ! lat]al ap]tures ( :i* are /opp$ s z to r5d] x capable ( produc+ ! same s\nd z ! =k1 ! feeble & sc>cely audible s\nd ( ! =k w be augm5t$ by ! ri* resonance ( ! column ( air )9 ! flute1 & ! tone w be full & cle>4 ,! s\nd w be f\nd greatly to decrease by clos+ or op5+ ano!r ap]ture2 = ! alt]ation 9 ! l5g? ( ! column ( air r5d]s x no long] fit p]fectly to reciprocate ! s\nd ( ! =k4 ,?is exp]im5t may be made on a conc]t flute ) a ,c tun+-=k4 ,b ,pr(essor ,:eat/one obs]ves1 t 9 ?is case x is g5]ally necess>y to f+] ! flute = ,b1 because1 :5 bl[n into ) ! m\?1 ! "u-lip p>tly cov]s ! emb\*ure1 :i* r5d]s ! s\nd ab\t a semitone flatt] ?an x w\ld be 7 ! emb\*ure entirely uncov]$4 ,he has also %[n1 by ! foll[+ exp]im5t1 t any "o among sev]al simultane\s s\nds may be r5d]$ sep>ately audible4 ,if two bottles be select$1 & tun$ by fill+ !m ) su* a quantity ( wat] z w r5d] !m unisonant ) two tun+-=ks :i* diff] 9 pit*1 on br++ bo? ( ! vibrat+ tun+-=ks to ! m\? ( ea* bottle alt]nately1 9 ea* case t s\nd only w be he>d :i* is reciprocat$ by ! unisonant bottle4 ,sev]al attempts h be5 made to imitate ! articulation ( ! lett]s ( ! alphabet4 ,ab\t ! ye> #aggi1 ,,mm4 ,kratz5/e9 ( ,/4 ,pet]sburg1 & ,kempel5 ( ,vi5na1 con/ruct$ in/rum5ts :i* articulat$ _m lett]s1 words1 & ev5 s5t5ces4 ,mr4 ,willis ( ,cambridge has adapt$ cyl9drical tubes to a re$1 ^: l5g? c be v>i$ at pleasure by slid+ jo9ts4 ,^u draw+ out a tube :ile a column ( air f ! bell[s ( an organ is pass+ ?r\gh x1 ! v[els are pron\nc$ 9 ! ord]1 i1 e1 a1 o1 u4 ,on ext5d+ ! tube1 !y are repeat$ aft] a c]ta9 int]val1 9 ! inv]t$ ord]1 u1 o1 a1 e1 i4 ,aft] ano!r int]val !y are aga9 obta9$ 9 ! direct ord]1 & s on4 ,:5 ! pit* ( ! re$ is v high1 x is impossible to s\nd "s ( ! v[els1 :i* is 9 p]fect correspond5ce ) ! human voice1 female s+]s be+ unable to pron\nce u & o 9 _! high notes4 ,f ! s+ul> discov]ies ( ,m4 ,sav>t on ! nature ( ! human voice1 & ! inve/igations ( ,mr4 ,willis on ! me*anism ( ! l>ynx1 x may be presum$ t ultimately ! utt]ance or pronunciation ( mod]n languages w be convey$1 n only to ! eye1 b also to ! e> ( po/]ity4 ,_h ! anci5ts possess$ ! means ( transmitt+ su* def9ite s\nds1 ! civilis$ _w w\ld /ill h respond$ 9 sympa!tic notes at ! di/ance ( _m ages4 ,,section ,,xviii4 ,refraction--,a/ronomical ,refraction & its ,laws--,=mation ( ,tables ( ,refraction--,t]re/rial ,refraction--,its ,quantity--,in/ances ( extraord9>y ,refraction--,reflection--,in/ances ( extraord9>y ,reflection--,loss ( ,light by ! ,absorb+ ,p[] ( ! ,atmosph]e--,app>5t ,magnitude ( ,sun & ,moon 9 ! ,horizon4 ,,n only ev]y?+ we he> b all we see is ?r\gh ! m$ium ( ! atmosph]e4 ,)\t "s k ( its action ^u light1 x w\ld be impossible to asc]ta9 ! position ( ! heav5ly bodies1 or ev5 to det]m9e ! exact place ( v di/ant objects ^u ! surface ( ! e>?2 =1 9 consequ5ce ( ! refractive p[] ( ! air1 no di/ant object is se5 9 its true position4 ,all ! cele/ial bodies appe> to be m elevat$ ?an !y really are2 because ! rays ( light1 in/ead ( mov+ ?r\gh ! atmosph]e 9 /raight l9es1 are cont9ually inflect$ t[>ds ! e>?4 ,light pass+ obliquely out ( a r>e into a d5s] m$ium1 z f vacuum into air1 or f air into wat]1 is b5t or refract$ f its c\rse t[>ds a p]p5dicul> to t po9t ( ! d5s] surface :]e ! light ent]s x 7,n4 #ahi74 ,9 ! same m$ium1 ! s9e ( ! angle conta9$ betwe5 ! incid5t ray & ! p]p5dicul> is 9 a con/ant ratio to ! s9e ( ! angle conta9$ by ! refract$ ray & ! same p]p5dicul>2 b ?is ratio v>ies ) ! refract+ m$ium4 ,! d5s] ! m$ium1 ! m ! ray is b5t4 ,! b>omet] %[s t ! d5sity ( ! atmosph]e decreases z ! height above ! e>? increases4 ,direct exp]im5ts prove t ! refractive p[] ( ! air increases ) its d5sity4 ,x foll[s !re=e t1 if ! temp]ature be uni=m1 ! refractive p[] ( ! air is greate/ at ! e>?'s surface1 & dim9i%es upw>ds4 ,a ray ( light f a cele/ial object fall+ obliquely on ?is v>iable atmosph]e1 in/ead ( be+ refract$ at once f its c\rse1 is gradually m & m b5t dur+ its passage ?r\gh x s z to move 9 a v]tical curv$ l9e1 9 ! same mann] z if ! atmosph]e consi/$ ( an inf9ite numb] ( /rata ( diff]5t d5sities4 ,! object is se5 9 ! direction ( a tang5t to t "p ( ! curve :i* meets ! eye2 consequ5tly ! app>5t altitude 7,n4 #aij7 ( ! heav5ly bodies is always great] ?an _! true altitude4 ,ow+ to ?is circum/ance1 ! />s are se5 above ! horizon aft] !y are set1 & ! day is l5g!n$ f a "p ( ! sun be+ visible1 ?\gh he really is beh9d ! rotundity ( ! e>?4 ,x w\ld be easy to det]m9e ! direction ( a ray ( light ?r\gh ! atmosph]e if ! law ( ! d5sity 7 kn[n2 b1 z ?is law is p]petually v>y+ ) ! temp]ature1 ! case is v complicat$4 ,:5 rays pass p]p5dicul>ly f "o m$ium into ano!r1 !y are n b5t2 & exp]i5ce %[s1 t 9 ! same surface1 ?\gh ! s9es ( ! angles ( incid5ce & refraction reta9 ! same ratio1 ! refraction increases ) ! obliquity ( incid5ce 7,n4 #ahi74 ,h5ce x appe>s t ! refraction is greate/ at ! horizon1 & at ! z5i? !re is none4 ,b x is prov$ t1 at all heights above t5 degrees1 refraction v>ies ne>ly z ! tang5t ( ! angul> di/ance ( ! object f ! z5i?1 & :olly dep5ds ^u ! heights ( ! b>omet] & !rmomet]4 ,= ! quantity ( refraction at ! same di/ance f ! z5i? v>ies ne>ly z ! height ( ! b>omet]1 ! temp]ature be+ con/ant2 & ! effect ( ! v>iation ( temp]ature is to dim9i% ! quantity ( refraction by ab\t its #dhj? "p = e degree 9 ! rise ( ,fahr5heit's !rmomet]4 ,n mu* reliance c be plac$ on cele/ial obs]vations1 )9 less ?an t5 or twelve degrees ( ! horizon1 on acc\nt ( irregul> v>iations 9 ! d5sity ( ! air ne> ! surface ( ! e>?1 :i* are sometimes ! cause ( v s+ul> ph5om5a4 ,! humidity ( ! air produces no s5sible effect on its refractive p[]2 & x has be5 prov$ t ! am\nt ( refraction is ! same :atev] be ! velocity ( ! incid5t light1 t is :e!r ! light comes f a /> 9 t "p ( ! heav5s t[>ds :i* ! e>? is go+1 or f "o 9 t "p ( ! sky :5ce x is rec$+4 ,bodies1 :e!r lum9\s or n1 are only visible by ! rays :i* proce$ f !m4 ,z ! rays mu/ pass ?r\gh /rata ( diff]5t d5sities 9 com+ to u1 x foll[s t1 ) ! exception ( />s 9 ! z5i?1 no object ei!r 9 or beyond our atmosph]e is se5 9 its true place4 ,b ! deviation is s small 9 ord9>y cases t x causes no inconv5i5ce1 ?\gh 9 a/ronomical & trigonometrical obs]vations due all[ance mu/ be made = ! effects ( refraction4 ,dr4 ,bradley's tables ( refraction 7 =m$ by obs]v+ ! z5i? di/ances ( ! sun at 8 greate/ decl9ations1 & ! z5i? di/ances ( ! pole-/> above & bel[ ! pole4 ,! sum ( ^! f\r quantities is equal to #ahj1 dim9i%$ by ! sum ( ! f\r refractions1 :5ce ! sum ( ! f\r refractions 0 obta9$2 &1 f ! law ( ! v>iation ( refraction det]m9$ by !ory1 he assign$ ! quantity due to ea* altitude 7,n4 #aia74 ,! mean horizontal refraction is ab\t #ce #f1 & at ! height ( =ty-five degrees x is #ehcf4 ,! effect ( refraction ^u ! same /> above & bel[ ! pole 0 notic$ by ,alhaz51 a ,s>ac5 a/ronom] ( ,spa91 9 ! n9? c5tury2 b its exi/5ce 0 kn[n to ,ptolemy 9 ! second1 ?\gh he 0 ignorant ( its quantity4 ,! refraction ( a t]re/rial object is e/imat$ diff]5tly f t ( a cele/ial body4 ,x is measur$ by ! angle conta9$ betwe5 ! tang5t to ! curvil9eal pa? ( ! ray :]e x meets ! eye1 & ! /raight l9e jo9+ ! eye & ! object 7,n4 #aib74 ,ne> ! e>?'s surface ! pa? ( ! ray may be suppos$ to be circul>2 & ! angle at ! c5tre ( ! e>? correspond+ to ?is pa? is call$ ! horizontal angle4 ,! quantity ( t]re/rial refraction is obta9$ by measur+ contemporane\sly ! elevation ( ! top ( a m\nta9 above a po9t 9 ! pla9 at its base1 & ! depression ( t po9t bel[ ! top ( ! m\nta94 ,! di/ance betwe5 ^! two /ations is ! *ord ( ! horizontal angle2 & x is easy to prove t d\ble ! refraction is equal to ! horizontal angle1 increas$ by ! diff]5ce betwe5 ! app>5t elevation & ! app>5t depression4 ,:5ce x appe>s t1 9 ! mean /ate ( ! atmosph]e1 ! refraction is ab\t ! f\rte5? "p ( ! horizontal angle4 ,"s v s+ul> appe>ances occur f ! accid5tal expansion or cond5sation ( ! /rata ( ! atmosph]e contigu\s to ! surface ( ! e>?1 by :i* di/ant objects1 in/ead ( be+ elevat$1 are depress$4 ,sometimes1 be+ at once bo? elevat$ & depress$1 !y appe> d\ble1 "o ( ! images be+ direct1 & ! o!r inv]t$4 ,9 consequ5ce ( ! upp] edges ( ! sun & moon be+ less refract$ ?an ! l[]1 !y (t5 appe> to be oval :5 ne> ! horizon4 ,! loom+ also or elevation ( coa/s1 m\nta9s1 & %ips1 :5 view$ across ! sea1 arises f unusual refraction4 ,a fri5d ( ! au?or's1 :ile /&+ on ! pla9s ( ,h9do/an1 saw ! :ole upp] *a9 ( ! ,himalaya ,m\nta9s />t into view1 f a sudd5 *ange 9 ! d5sity ( ! air1 occasion$ by a heavy %[] aft] a v long c\rse ( dry & hot wea!r4 ,s+le & d\ble images ( objects at sea1 aris+ f sudd5 *anges ( temp]ature :i* are n s soon communicat$ to ! wat] on acc\nt ( its d5sity z to ! air1 occur m r>ely & are ( %ort] duration ?an simil> appe>ances on l&4 ,9 #ahah ,capta9 ,scoresby1 ^: obs]vations on ! ph5om5a ( ! pol> seas are s valuable1 recognis$ 8 fa!r's %ip by its inv]t$ image 9 ! air1 al?\gh ! vessel itself 0 bel[ ! horizon4 ,he aft]w>ds f\nd t %e 0 sev5te5 miles beyond ! horizon1 & ?irty miles di/ant4 ,two images are sometimes se5 susp5d$ 9 ! air ov] a %ip1 "o direct & ! o!r inv]t$1 ) _! topma/s or _! hulls meet+1 accord+ z ! inv]t$ image is above or bel[ ! direct image 7,n4 #aic74 ,dr4 ,wolla/on has prov$ t ^! appe>ances are ow+ to ! refraction ( ! rays ?r\gh m$ia ( diff]5t d5sities1 by ! v simple exp]im5t ( look+ along a r$-hot pok] at a di/ant object4 ,two images are se51 "o direct & ano!r inv]t$1 9 consequ5ce ( ! *ange induc$ by ! heat 9 ! d5sity ( ! adjac5t air4 ,he produc$ ! same effect by a sal9e or sac*>9e solution ) wat] & _s ( w9e float+ ^u x 7,n4 #aid74 ,_m ( ! ph5om5a t h be5 ascrib$ to extraord9>y refraction seem to be occasion$ by a p>tial or total reflection ( ! rays ( light at ! surfaces ( /rata ( diff]5t d5sities 7,n4 #ahi74 ,x is well kn[n t1 :5 light falls obliquely ^u ! ext]nal surface ( a transp>5t m$ium1 z on a plate ( glass or a /ratum ( air1 "o portion is reflect$ & ! o!r transmitt$4 ,b1 :5 light falls v obliquely ^u ! int]nal surface1 ! :ole is reflect$1 & n a ray is transmitt$4 ,9 all cases ! angles made by ! incid5t & reflect$ rays ) a p]p5dicul> to ! surface be+ equal1 z ! brightness ( ! reflect$ image dep5ds on ! quantity ( light1 ^? aris+ f total reflection mu/ be by f> ! mo/ vivid4 ,! delusive appe>ance ( wat]1 s well kn[n to ,african travell]s & to ! ,arab ( ! des]t z ! ,lake ( ! ,gazelles1 is ascrib$ to ! reflection :i* takes place betwe5 /rata ( air ( diff]5t d5sities1 ow+ to radiation ( heat f ! arid s&y pla9s4 ,! mirage describ$ by ,capta9 ,mundy 9 8 ,j\rnal ( a ,t\r 9 ,india probably arises f ?is cause4 8,a deep precipit\s valley bel[ u1 at ! bottom ( :i* ,i _h se5 "o or two mis]able villages 9 ! morn+1 bore 9 ! ev5+ a complete resemblance to a beautiful lake2 ! vap\r :i* play$ ! "p ( wat] asc5d+ ne>ly half way up ! sides ( ! vale1 & on its bright surface trees & rocks be+ di/9ctly reflect$4 ,i _h n be5 long contemplat+ ?is ph5om5on1 be=e a sudd5 /orm came on & dropp$ a curta9 ( cl\ds ov] ! sc5e40 ,an occurr5ce :i* happ5$ on ! #ah? ( ,novemb]1 #ahjd1 0 probably produc$ by reflection4 ,dr4 ,bu*an1 :ile wat*+ ! ris+ sun f ! cliff ab\t a mile to ! ea/ ( ,brighton1 at ! in/ant ! sol> disc em]g$ f ! surface ( ! ocean1 saw ! cliff on :i* he 0 /&+1 a w9dmill1 8 own figure & t ( a fri5d1 depict$ imm$iately opposite to him on ! sea4 ,?is appe>ance la/$ ab\t t5 m9utes1 till ! sun _h ris5 ne>ly 8 own diamet] above ! surface ( ! waves4 ,! :ole !n seem$ to be elevat$ into ! air1 & successively vani%$4 ,! rays ( ! sun fell ^u ! cliff at an incid5ce ( #gc f ! p]p5dicul>1 & ! sea 0 cov]$ ) a d5se fog _m y>ds 9 height1 :i* gradually rec$$ be=e ! ris+ sun4 ,:5 extraord9>y refraction takes place lat]ally1 ! /rata ( v>iable d5sity are p]p5dicul> to ! horizon1 &1 if comb9$ ) v]tical refraction1 ! objects are magnifi$ z :5 se5 ?r\gh a telescope4 ,f ?is cause1 on ! #bf? ( ,july1 #agih1 ! cliffs ( ,france1 fifty miles (f1 7 se5 z di/9ctly f ,ha/+s z if !y _h be5 close at h&2 & ev5 ,dieppe 0 said to h be5 visible 9 ! aft]noon4 ,! /ratum ( air 9 ! horizon is s mu* ?ick] & m d5se ?an ! /ratum 9 ! v]tical1 t ! sun's light is dim9i%$ #acjj times 9 pass+ ?r\gh x1 :i* enables u to look at him :5 sett+ )\t be+ dazzl$4 ,! loss ( light1 & consequ5tly ( heat1 by ! absorb+ p[] ( ! atmosph]e1 increases ) ! obliquity ( incid5ce4 ,( t5 ?\s& rays fall+ on its surface1 #habc arrive at a giv5 po9t ( ! e>? if !y fall p]p5dicul>ly2 #gjbd arrive if ! angle ( direction be fifty degrees2 #bhca1 if x be sev5 degrees2 & only five rays w arrive ?r\gh a horizontal /ratum4 ,s9ce s great a quantity ( light is lo/ 9 pass+ ?r\gh ! atmosph]e1 _m cele/ial objects are altoge!r invisible f ! pla91 :i* may be se5 f elevat$ situations4 ,dim9i%$ spl5d\r1 & ! false e/imate we make ( di/ance f ! numb] ( int]v5+ objects1 lead u to suppose ! sun & moon to be mu* l>g] :5 9 ! horizon ?an at any o!r altitude1 ?\gh _! app>5t diamet]s are !n some:at less4 ,in/ead ( ! sudd5 transitions ( light & d>kness1 ! reflective p[] ( ! air adorns nature ) ! rosy & gold5 hues ( ! ,aurora & twilight4 ,ev5 :5 ! sun is eighte5 degrees bel[ ! horizon1 a suffici5t portion ( light rema9s to %[ t at ! height ( ?irty miles x is /ill d5se en\gh to reflect light4 ,! atmosph]e scatt]s ! sun's rays1 & gives all ! beautiful t9ts & *e]fulness ( day4 ,x transmits ! blue light 9 greate/ abundance2 ! high] we asc5d1 ! sky assumes a deep] hue2 b1 9 ! expanse ( space1 ! sun & />s mu/ appe> l brilliant specks 9 pr(\nd blackness4 ,,section ,,xix4 ,con/itution ( ,light accord+ to ,sir ,isaac ,newton--,absorption ( ,light--,col\rs ( ,bodies--,con/itution ( ,light accord+ to ,sir ,david ,brew/]--,new ,col\rs--,fraunh(]'s ,d>k ,l9es--,disp]sion ( ,light--,! ,a*romatic ,telescope--,homog5e\s ,light--,accid5tal & ,complem5t>y ,col\rs--,m4 ,plateau's ,exp]im5ts & ,!ory ( ,accid5tal ,col\rs4 ,,x is impossible ?us to trace ! pa? ( a sunbeam ?r\gh our atmosph]e )\t feel+ a desire to "k its nature1 by :at p[] x trav]ses ! imm5sity ( space1 & ! v>i\s modifications x und]goes at ! surfaces & 9 ! int]ior ( t]re/rial sub/ances4 ,sir ,isaac ,newton prov$ ! comp\nd nature ( :ite light1 z emitt$ f ! sun1 by pass+ a sunbeam ?r\gh a glass prism 7,n4 #aie71 :i*1 sep>at+ ! rays by refraction1 =m$ a spectrum or oblong image ( ! sun1 consi/+ ( sev5 col\rs1 r$1 orange1 yell[1 gre51 blue1 indigo1 & violet--( :i* ! r$ is ! lea/ refrangible1 & ! violet ! mo/4 ,b1 :5 he reunit$ ^! sev5 rays by means ( a l5s1 ! comp\nd beam became pure :ite z be=e4 ,he insulat$ ea* col\r$ ray1 &1 f9d+ t x 0 no long] capable ( decomposition by refraction1 conclud$ t :ite light consi/s ( sev5 k9ds ( homog5e\s light1 & t to ! same col\r ! same refrangibility ev] belongs1 & to ! same refrangibility ! same col\r4 ,s9ce ! discov]y ( absorb5t m$ia1 h[ev]1 x appe>s t ?is is n ! con/itution ( ! sol> spectrum4 ,we "k ( no sub/ance t is ei!r p]fectly opaque or p]fectly transp>5t4 ,ev5 gold may be beat5 s ?9 z to be p]vi\s to light4 ,on ! contr>y1 ! cle>e/ cry/al1 ! pure/ air or wat]1 /ops or absorbs its rays :5 transmitt$1 & gradually ext+ui%es !m z !y p5etrate to great] dep?s4 ,on ?is acc\nt objects _c be se5 at ! bottom ( v deep wat]1 & _m m />s are visible to ! nak$ eye f ! tops ( m\nta9s ?an f ! valleys4 ,! quantity ( light t is incid5t on any transp>5t sub/ance is always great] ?an ! sum ( ! reflect$ & refract$ rays4 ,a small quantity is irregul>ly reflect$ 9 all directions by ! imp]fections ( ! poli% by :i* we are enabl$ to see ! surface2 b a mu* great] portion is absorb$ by ! body4 ,bodies t reflect all ! rays appe> :ite1 ^? t absorb !m all seem black2 b mo/ sub/ances1 aft] decompos+ ! :ite light :i* falls ^u !m1 reflect "s col\rs & absorb ! re/4 ,a violet reflects ! violet rays alone & absorbs ! o!rs4 ,sc>let clo? absorbs almo/ all ! col\rs except r$4 ,yell[ clo? reflects ! yell[ rays mo/ abundantly1 & blue clo? ^? t are blue4 ,consequ5tly col\r is n a prop]ty ( matt]1 b arises f ! action ( matt] ^u light4 ,9 fact1 ! law ( action & reaction obta9s 9 light z 9 e o!r dep>tm5t ( nature1 s t light _c be reflect$1 refract$1 mu* less absorb$1 by any m$ium )\t be+ react$ ^u by x4 ,?us a :ite rib& reflects all ! rays1 b1 :5 dy$ r$1 ! p>ticles ( ! silk acquire ! prop]ty ( reflect+ ! r$ rays mo/ abundantly & ( absorb+ ! o!rs4 ,^u ?is prop]ty ( unequal absorption ! col\rs ( transp>5t m$ia dep5d2 = !y also receive _! col\r f _! p[] ( /opp+ or absorb+ "s ( ! col\rs ( :ite light1 & transmitt+ o!rs4 ,z1 = example1 black & r$ inks1 ?\gh equally homog5e\s1 absorb diff]5t k9ds ( rays2 &1 :5 expos$ to ! sun1 !y become heat$ 9 diff]5t degrees2 :ile pure wat] seems to transmit all rays equally1 & is n s5sibly heat$ by ! pass+ light ( ! sun4 ,! ri* d>k light transmitt$ by a smalt-blue f+]-glass is n a homog5e\s col\r l ! blue or indigo ( ! spectrum1 b is a mixture ( all ! col\rs ( :ite light :i* ! glass has n absorb$4 ,! col\rs absorb$ are su* z mix$ ) ! blue t9t w\ld =m :ite light4 ,:5 ! spectrum ( sev5 col\rs is view$ ?r\gh a ?9 plate ( ?is glass1 !y are all visible2 &1 :5 ! plate is v ?ick1 e col\r is absorb$ betwe5 ! extreme r$ & ! extreme violet1 ! int]val be+ p]fectly black2 b1 if ! spectrum be view$ ?r\gh a c]ta9 ?ickness ( ! glass int]m$iate betwe5 ! two1 x w be f\nd t ! middle ( ! r$ space1 ! :ole ( ! orange1 a great "p ( ! gre51 a consid]able "p ( ! blue1 a little ( ! indigo1 & a v little ( ! violet1 vani%1 be+ absorb$ by ! blue glass2 & t ! yell[ rays occupy a l>g] space1 cov]+ "p ( t =m]ly occupi$ by ! orange on "o side & by ! gre5 on ! o!r3 s t ! blue glass absorbs ! r$ light1 :i* :5 mix$ ) ! yell[ con/itutes orange2 & also absorbs ! blue light1 :i* :5 mix$ ) ! yell[ =ms ! "p ( ! gre5 space next to ! yell[4 ,h5ce1 by absorption1 gre5 light is decompos$ into yell[ & blue1 & orange light into yell[ & r$3 consequ5tly ! orange & gre5 rays1 ?\gh incapable ( decomposition by refraction1 c be resolv$ by absorption1 & actually consi/ ( two diff]5t col\rs possess+ ! same degree ( refrangibility4 ,diff]5ce ( col\r1 !re=e1 is n a te/ ( diff]5ce ( refrangibility1 & ! conclusion d$uc$ by ,newton is no long] admissible z a g5]al tru?4 ,by ?is analysis ( ! spectrum1 n only ) blue glass b ) a v>iety ( col\r$ m$ia1 ,sir ,david ,brew/]1 s ju/ly celebrat$ = 8 optical discov]ies1 is ( op9ion t ! sol> spectrum consi/s ( ?ree prim>y col\rs1 r$1 yell[1 & blue1 ea* ( :i* exi/s ?r\gh\t its :ole ext5t1 b ) diff]5t degrees ( int5sity 9 diff]5t p>ts2 & t ! sup]position ( ^! ?ree produces all ! sev5 hues accord+ z ea* prim>y col\r is 9 excess or defect4 ,t s9ce a c]ta9 portion ( r$1 yell[1 & blue rays con/itute :ite light1 ! col\r ( any po9t ( ! spectrum may be consid]$ z consi/+ ( ! pr$om9at+ col\r at t po9t mix$ ) :ite light4 ,consequ5tly1 8by absorb+ ! excess ( any col\r at any po9t ( ! spectrum above :at is necess>y to =m :ite light1 su* :ite light w appe> at t po9t z nev] mortal eye look$ ^u be=e ?is exp]im5t1 s9ce x possesses ! rem>kable prop]ty ( rema9+ ! same aft] any numb] ( refractions1 & ( be+ capable ( decomposition by absorption alone40 ,?is analysis ( light has be5 call$ 9 "q by ,pr(essor ,*allis1 ( ,cambridge1 :o does n admit ( any resolution by absorb+ m$ia diff]5t f t by ! prism1 ?\gh he admits t a mixture ( blue & yell[ sol> light produces gre54 ,pr(essor ,/okes1 on ! contr>y1 does n all[ t a mixture ( blue & yell[ sol> light produces gre51 al?\gh t mixture produces gre5 :5 ! light is f o!r s\rces1 = he f\nd ! gradation f sunlight to pass f yell[ ?r\gh dilut$ yell[1 :ite1 dilut$ blue to blue2 s he does n admit ( ,sir ,david ,brew/]'s analysis ( ! spectrum2 h[ev]1 !re appe>s to be /ill a d\bt z to ! real "* ( ! ph5om5a pres5t$ by c]ta9 absorb+ sub/ances4 ,9 addition to ! sev5 col\rs ( ! ,newtonian spectrum1 ,sir ,john ,h]s*el has discov]$ a set ( v d>k r$ rays beyond ! r$ extremity ( ! spectrum :i* c only be se5 :5 ! eye is def5d$ f ! gl>e ( ! o!r col\rs by a d>k blue cobalt glass4 ,he has also f\nd t beyond ! extreme violet !re are visible rays ( a lav5d] gray col\r1 :i* may be se5 by ?r[+ ! spectrum on a %eet ( pap] moi/5$ by ! c>bonate ( soda4 ,! illum9at+ p[] ( ! diff]5t rays ( ! spectrum v>ies ) ! col\r4 ,! mo/ int5se light is 9 ! mean yell[ ray1 or1 accord+ to ,m4 ,fraunh(]1 at ! b\nd>y ( ! orange & yell[4 ,:5 ! prism is v p]fect & ! sunbeam small1 s t ! spectrum may be receiv$ on a %eet ( :ite pap] 9 its utmo/ /ate ( purity1 x pres5ts ! appe>ance ( a rib& %ad$ ) all ! prismatic col\rs1 hav+ its bread? irregul>ly /rip$ or subdivid$ by an indef9ite numb] ( d>k1 & sometimes black l9es4 ,! great] numb] ( ^! rayless l9es are s extremely n>r[ t x is impossible to see !m 9 ord9>y circum/ances4 ,! be/ me?od is to receive ! spectrum on ! object-glass ( a telescope1 s z to magnify !m suffici5tly to r5d] !m visible4 ,?is exp]im5t may also be made1 b 9 an imp]fect mann]1 by view+ a n>r[ slit betwe5 two ne>ly clos$ w9d[-%utt]s ?r\gh a v excell5t glass prism held close to ! eye1 ) its refract+ angle p>allel to ! l9e ( light4 ,! rayless l9es 9 ! r$ portion ( ! spectrum become mo/ visible z ! sun approa*es ! horizon1 :ile ^? 9 ! blue extremity are mo/ obvi\s 9 ! middle ( ! day4 ,:5 ! spectrum is =m$ by ! sun's rays1 ei!r direct or indirect--z f ! sky1 cl\ds1 ra9b[1 moon1 or planets--! black b&s are always f\nd to be 9 ! same p>ts ( ! spectrum1 & "u all circum/ances to ma9ta9 ! same relative positions4 ,simil> d>k l9es are also se5 9 ! light ( ! />s1 9 ! electric light1 & 9 ! flame ( combu/ible sub/ances1 ?\gh diff]5tly arrang$1 ea* /> & ea* flame hav+ a sy/em ( d>k l9es peculi> to itself4 ,dr4 ,wolla/on & ,m4 ,fraunh(]1 ( ,muni*1 discov]$ ^! l9es defici5t ( rays indep5d5tly ( ea* o!r4 ,m4 ,fraunh(] f\nd t _! numb] ext5ds to ne>ly six hundr$1 b !y are mu* m num]\s4 ,!re are bright l9es 9 ! sol> spectrum :i* also ma9ta9 a fix$ position4 ,among ! d>k l9es1 ,m4 ,fraunh(] select$ sev5 ( ! mo/ rem>kable1 & det]m9$ _! di/ances s accurately1 t !y n[ =m /&>d & inv>iable po9ts ( ref]5ce = measur+ ! refractive p[]s ( diff]5t m$ia on ! rays ( light1 :i* r5d]s ?is dep>tm5t ( optics z exact z any ( ! physical sci5ces4 ,^! l9es are designat$ by ! lett]s ( ! alphabet1 beg9n+ ) ,b1 :i* is 9 ! r$ ne> ! end ( ! spectrum2 ,c is f>!r advanc$ 9 ! r$2 ,d is 9 ! orange2 ,e 9 ! gre52 ,f 9 ! blue2 ,g 9 ! indigo2 & ,h 9 ! violet4 ,by means ( ^! fix$ po9ts1 ,m4 ,fraunh(] has asc]ta9$ f prismatic obs]vation ! refrangibility ( sev5 ( ! pr9cipal rays 9 ea* ( t5 diff]5t sub/ances solid & liquid4 ,! refraction increas$ 9 all f ! r$ to ! violet end ( ! spectrum4 ,! rays t are want+ 9 ! sol> spectrum1 :i* occasion ! d>k l9es1 7 suppos$ to be absorb$ by ! atmosph]e ( ! sun4 ,b ! annul> eclipse :i* happ5$ on ! #ae? ( ,may1 #ahcf1 af=d$ ,pr(essor ,=bes ! means ( prov+ t ! d>k l9es 9 "q _c be attribut$ to ! absorption ( ! sol> atmosph]e2 !y 7 nei!r broad] nor m num]\s 9 ! spectrum =m$ dur+ t ph5om5on ?an at any o!r "t1 ?\gh ! rays came only f ! circumf]5ce ( ! sun's disc1 & consequ5tly _h to trav]se a great] dep? ( 8 atmosph]e4 ,sir ,david ,brew/] f\nd t 9 c]ta9 /ates ( ! atmosph]e ! obscure l9es become mu* broad]1 & "s ( !m deeply black2 & he obs]v$ also1 t1 at ! "t ! sun 0 sett+ 9 a veil ( r$ light1 "p ( ! lum9\s spectrum 0 absorb$1 :5ce he conclud$ t ! e>?'s atmosph]e _h absorb$ ! rays ( light :i* occupi$ ! d>k b&s4 ,by direct exp]im5ts also ! atmosph]e 0 obs]v$ to act p[]fully ^u ! rayless l9es4 ,:5 a l5s is us$ along ) a prism1 longitud9al d>k l9es ( diff]5t bread?s are se5 to cross ! b&s1 already describ$1 at "r angles2 ^! ,m4 ,ragona-,sc9a & ,m4 ,bab9et believe to be l9es ( int]f]5ce :i* exi/ 9 light t has pass$ ?r\gh a convex l5s4 ,! l9es are diff]5t bo? 9 k9d & numb] 9 ! spectra ( gases & flames4 ,9 a highly-magnifi$ spectrum f light pass$ ?r\gh nitr\s acid gas1 ,sir ,david ,brew/] c\nt$ #bjjj d>k b&s4 ,9 ! spectrum ( a lamp1 & g5]ally ( all :ite flames1 none ( ! defective l9es are f\nd2 s all su* flames conta9 rays :i* d n exi/ 9 ! light ( ! sun or />s4 ,brilliant r$ l9es appe> 9 ! spectrum produc$ by ! combu/ion ( nitre ^u *>coal2 & 9 all artificial flames d>k & bright b&s exi/1 sometimes correspond+ 9 position ) ^? 9 ! sol> spectrum1 & sometimes n4 ,a sunbeam receiv$ on a scre51 aft] pass+ ?r\gh a small r\nd hole 9 a w9d[-%utt]1 appe>s l a r\nd :ite spot2 b :5 a prism is int]pos$1 ! beam no long] occupies ! same space4 ,x is sep>at$ into ! prismatic col\rs1 & spread ov] a l9e ( consid]able l5g?1 :ile its bread? rema9s ! same ) t ( ! :ite spot4 ,! act ( spread+ or sep>ation is call$ ! disp]sion ( ! col\r$ rays4 ,disp]sion always takes place 9 ! plane ( refraction1 & is great] z ! angle ( incid5ce is great]4 ,x v>ies inv]sely z ! l5g? ( a wave ( light1 & directly z its velocity3 h5ce t[>ds ! blue end ( ! spectrum1 :]e ! undulations ( ! rays are lea/1 ! disp]sion is greate/4 ,sub/ances h v diff]5t disp]sive p[]s2 t is to say1 ! spectra =m$ by two equal prisms ( diff]5t sub/ances1 "u precisely ! same circum/ances1 are ( diff]5t l5g?s4 ,?us1 if a prism ( fl9t-glass & "o ( cr[n-glass ( equal refract+ angles be pres5t$ to two rays ( :ite light at equal angles1 x w be f\nd t ! space ov] :i* ! col\r$ rays are disp]s$ by ! fl9t-glass is mu* great] ?an ! space occupi$ by t produc$ by ! cr[n-glass3 & z ! quantity ( disp]sion dep5ds ^u ! refract+ angle ( ! prism1 ! angles ( ! two prisms may be made su* t1 :5 ! prisms are plac$ close toge!r ) _! edges turn$ opposite ways1 !y w exactly oppose ea* o!r's action1 & w refract ! col\r$ rays equally1 b 9 contr>y directions1 s t an exact comp5sation w be effect$1 & ! light w be refract$ )\t col\r 7,n4 #aie74 ,! a*romatic telescope is con/ruct$ on ?is pr9ciple4 ,x consi/s ( a tube ) an object-glass or l5s at "o end to br+ ! rays to a focus1 & =m an image ( ! di/ant object1 & a magnify+-glass at ! o!r end to view ! image ?us =m$4 ,n[ x is f\nd t ! object-glass1 in/ead ( mak+ ! rays conv]ge to "o po9t1 disp]ses !m1 & gives a confus$ & col\r$ image3 b by con/ruct+ x ( two l5ses 9 contact1 "o ( fl9t & ! o!r ( cr[n-glass ( c]ta9 =ms & proportions1 ! disp]sion is c\nt]act$1 & a p]fectly well-def9$ & col\rless image ( ! object is =m$ 7,n4 #aif74 ,x 0 ?\ght to be impossible to produce refraction )\t col\r1 till ,mr4 ,hall1 a g5tleman ( ,worce/]%ire1 con/ruct$ a telescope on ?is pr9ciple 9 ! ye> #agcc2 & tw5ty-five ye>s aft]w>ds ! a*romatic telescope 0 br\ght to p]fection by ,mr4 ,dollond1 a celebrat$ optician 9 ,london4 ,by means ( ,mr4 ,fraunh(]'s det]m9ation ( ! refraction ( ! pr9cipal rays 9 sub/ances1 _! disp]sive p[]s may be f\nd 7,n4 #aig74 ,a p]fectly homog5e\s col\r is v r>ely to be f\nd2 b ! t9ts ( all sub/ances are mo/ brilliant :5 view$ 9 light ( _! own col\r4 ,! r$ ( a waf] is mu* m vivid 9 r$ ?an 9 :ite light2 :]eas1 if plac$ 9 homog5e\s yell[ light1 x c no long] appe> r$1 because !re is n a ray ( r$ 9 ! yell[ light4 ,7 x n t ! waf]1 l all o!r bodies1 :e!r col\r$ or n1 reflects :ite light at its out] surface1 x w\ld appe> absolutely black :5 plac$ 9 yell[ light4 ,aft] look+ /eadily = a %ort "t at a col\r$ object1 su* z a r$ waf]1 on turn+ ! eyes to a :ite sub/ance1 a gre5 image ( ! waf] appe>s1 :i* is call$ ! accid5tal col\r ( r$4 ,all t9ts h _! accid5tal col\rs3 ?us ! accid5tal col\r ( orange is blue2 t ( yell[ is indigo2 ( gre51 r$di% :ite2 ( blue1 orange-r$2 ( violet1 yell[2 & ( :ite1 black2 & vice v]s4 ,:5 ! direct & accid5tal col\rs are ( ! same int5sity1 ! accid5tal is !n call$ ! complem5t>y col\r1 because any two col\rs are said to be complem5t>y to "o ano!r :i* produce :ite :5 comb9$4 ,f exp]im5ts by ,m4 ,plateau ( ,brussels1 x appe>s t two complem5t>y col\rs f direct impression1 :i* w\ld produce :ite :5 comb9$1 produce black1 or ext+ui% "o ano!r1 by _! union1 :5 accid5tal2 & also t ! comb9ation ( all ! t9ts ( ! sol> spectrum produces :ite light if !y be f a direct impression on ! eye1 :]eas blackness results f a union ( ! same t9ts if !y be accid5tal2 & 9 e case :]e ! real col\rs produce :ite by _! comb9ation1 ! accid5tal col\rs ( ! same t9ts produce black4 ,:5 ! image ( an object is impress$ on ! ret9a only = a few mom5ts1 ! picture left is exactly ( ! same col\r ) ! object1 b 9 an extremely %ort "t ! picture is succe$$ by ! accid5tal image4 ,m4 ,plateau attributes ?is ph5om5on to a reaction ( ! ret9a aft] be+ excit$ by direct vision1 s t ! accid5tal impression is ( an opposite nature to ! correspond+ direct impression4 ,he conceives t :5 ! eye is excit$ by be+ fix$ = a "t on a col\r$ object1 & !n )drawn f ! excitem5t1 x endeav\rs to return to its /ate ( repose2 b 9 s do+1 t x passes ?is po9t1 & spontane\sly assumes an opposite condition1 l a spr+ :i*1 b5t 9 "o direction1 9 return+ to its /ate ( re/ b5ds z mu* ! contr>y way4 ,! accid5tal image ?us results f a p>ticul> modification ( ! organ ( sight1 9 virtue ( :i* x spontane\sly gives u a new s5sation aft] x has be5 excit$ by direct vision4 ,if ! prevail+ impression be a v /rong :ite light1 its accid5tal image is n black1 b a v>iety ( col\rs 9 succession4 ,accord+ to ,m4 ,plateau1 ! ret9a (f]s a resi/ance to ! action ( light1 :i* increases ) ! duration ( ?is action2 :5ce1 aft] look+ int5tly at an object = a long "t1 x appe>s to decrease 9 brilliancy4 ,! imag9ation has a p[]ful influ5ce on our optical impressions1 & has be5 kn[n to revive ! images ( highly lum9\s objects mon?s1 & ev5 ye>s1 aft]w>ds4 ,,section ,,xx4 ,int]f]5ce ( ,light--,undulatory ,!ory ( ,light--,propagation ( ,light--,newton's ,r+s--,measurem5t ( ! ,l5g? ( ! ,waves ( ,light1 & ( ! ,frequ5cy ( ! ,vibrations ( ,e!r = ea* ,col\r--,newton's ,scale ( ,col\rs--,diffraction ( ,light--,sir ,john ,h]s*el's ,!ory ( ! ,absorption ( ,light--,refraction & ,reflection ( ,light4 ,,newton & mo/ ( 8 imm$iate successors imag9$ light to be a mat]ial sub/ance1 emitt$ by all self-lum9\s bodies 9 extremely m9ute p>ticles1 mov+ 9 /raight l9es ) prodigi\s velocity1 :i*1 by imp++ ^u ! optic n]ves1 produce ! s5sation ( light4 ,_m ( ! obs]v$ ph5om5a h be5 expla9$ by ?is !ory2 x is1 h[ev]1 totally inadequate to acc\nt = ! foll[+ circum/ances4 ,:5 two equal rays ( r$ light1 proce$+ f two lum9\s po9ts1 fall ^u a %eet ( :ite pap] 9 a d>k room1 !y produce a r$ spot on x :i* w be twice z bright z ei!r ray w\ld produce s+ly1 provid$ ! diff]5ce 9 ! l5g?s ( ! two beams1 f ! lum9\s po9ts to ! r$ spot on ! pap]1 be exactly ! #jjjjjbeh? "p ( an in*4 ,! same effect w take place if ! diff]5ce 9 ! l5g?s be twice1 ?ree times1 f\r times1 c41 t quantity4 ,b if ! diff]5ce 9 ! l5g?s ( ! two rays be equal to "o-half ( ! #jjjjjbeh? "p ( an in*1 or to its #a-a_/b1 #b-a_/b1 #c-a_/b1 c41 "p1 ! "o light w entirely ext+ui% ! o!r1 & w produce absolute d>kness on ! pap] :]e ! unit$ beams fall4 ,if ! diff]5ce 9 ! l5g?s ( _! pa?s be equal to ! #a-a_/d1 #b-a_/d1 #c-a_/d1 c41 ( ! #jjjjjbeh? "p ( an in*1 ! r$ spot aris+ f ! comb9$ beams w be ( ! same int5sity :i* "o alone w\ld produce4 ,if violet light be employ$1 ! diff]5ce 9 ! l5g?s ( ! two beams mu/ be equal to ! #jjjjjaeg? "p ( an in*1 9 ord] to produce ! same ph5om5a2 & = ! o!r col\rs1 ! diff]5ce mu/ be int]m$iate betwe5 ! #jjjjjbeh? & ! #jjjjjaeg? "p ( an in*4 ,simil> ph5om5a may be se5 by view+ ! flame ( a c&le ?r\gh two v f9e slits 9 a c>d extremely ne> to "o ano!r 7,n4 #aih72 or by admitt+ ! sun's light into a d>k room ?r\gh a p9-hole ab\t ! =tie? ( an in* 9 diamet]1 receiv+ ! image on a %eet ( :ite pap]1 & hold+ a sl5d] wire 9 ! light4 ,its %ad[ w be f\nd to consi/ ( a bright :ite b> or /ripe 9 ! middle1 ) a s]ies ( alt]nate black & brightly-col\r$ /ripes on ea* side4 ,! rays :i* b5d r\nd ! wire 9 two /reams are ( equal l5g?s 9 ! middle /ripe2 x is consequ5tly d\bly bright f _! comb9$ effect2 b ! rays :i* fall on ! pap] on ea* side ( ! bright /ripe1 be+ ( su* unequal l5g?s z to de/roy "o ano!r1 =m black l9es4 ,on ea* side ( ^! black l9es ! rays are aga9 ( su* l5g?s z to comb9e to =m bright /ripes1 & s on alt]nately till ! light is too fa9t to be visible4 ,:5 any homog5e\s light is us$1 su* z r$1 ! alt]nations are only black & r$2 b on acc\nt ( ! het]og5e\s nature ( :ite light1 ! black l9es alt]nate ) vivid /ripes or fr+es ( prismatic col\rs1 aris+ f ! sup]position ( sy/ems ( alt]nate black l9es & l9es ( ea* homog5e\s col\r4 ,t ! alt]nation ( black l9es & col\r$ fr+es actually does arise f ! mixture ( ! two /reams ( light :i* fl[ r\nd ! wire1 is prov$ by _! vani%+ ! in/ant "o ( ! /reams is int]rupt$4 ,x may !re=e be conclud$1 z (t5 z ^! /ripes ( light & d>kness occur1 t !y are ow+ to ! rays comb9+ at c]ta9 int]vals to produce a jo9t effect1 & at o!rs to ext+ui% "o ano!r4 ,n[ x is contr>y to all our ideas ( matt] to suppose t two p>ticles ( x %\ld annihilate "o ano!r "u any circum/ances :atev]2 :ile1 on ! contr>y1 two oppos+ motions may2 & x is impossible n to be /ruck ) ! p]fect simil>ity betwe5 ! int]f]5ces ( small undulations ( air or ( wat] & ! prec$+ ph5om5a4 ,! analogy is inde$ s p]fect1 t philosoph]s ( ! highe/ au?ority concur 9 ! belief t ! cele/ial regions are fill$ ) an extremely r>e & highly ela/ic m$ium or e!r1 ^: p>ticles are capable ( receiv+ ! vibrations communicat$ to !m by self-lum9\s bodies1 & ( transmitt+ !m to ! optic n]ves1 s z to produce ! s5sation ( light4 ,! accel]ation 9 ! mean motion ( ,encke's comet1 z well z ( ! comet discov]$ by ,m4 ,biela1 r5d]s ! exi/5ce ( su* a m$ium c]ta94 ,x is cle> t1 9 ?is hypo!sis1 ! alt]nate /ripes ( light & d>kness are entirely ! effect ( ! int]f]5ce ( ! undulations2 =1 by actual measurem5t1 ! l5g? ( a wave ( ! mean r$ rays ( ! sol> spectrum is equal to ! #jjjjjbeh? "p ( an in*2 consequ5tly1 :5 ! elevations ( ! waves comb9e1 !y produce d\ble ! int5sity ( light t ea* w\ld d s+ly2 & :5 half a wave comb9es ) a :ole--t is1 :5 ! holl[ ( "o wave is fill$ up by ! elevation ( ano!r--d>kness is ! result4 ,at int]m$iate po9ts betwe5 ^! extremes1 ! int5sity ( ! light corresponds to int]m$iate diff]5ces 9 ! l5g?s ( ! rays4 ,! !ory ( int]f]5ces is a p>ticul> case ( ! g5]al me*anical law ( ! sup]position ( small motions2 :5ce x appe>s t ! di/urbance ( a p>ticle ( an ela/ic m$ium1 produc$ by two co-exi/5t undulations1 is ! sum ( ! di/urbances :i* ea* undulation w\ld produce sep>ately2 consequ5tly1 ! p>ticle w move 9 ! diagonal ( a p>allelogram1 ^: sides are ! two undulations4 ,if1 !re=e1 ! two undulations agree 9 direction1 or ne>ly s1 ! result+ motion w be v ne>ly equal to _! sum1 & 9 ! same direction2 if !y ne>ly oppose "o ano!r1 ! result+ motion w be ne>ly equal to _! diff]5ce2 &1 if ! undulations be equal & opposite1 ! resultant w be z]o1 & ! p>ticle w rema9 at re/4 ,! prec$+ exp]im5ts1 & ! inf]5ces d$uc$ f !m1 :i* h l$ to ! e/abli%m5t ( ! doctr9e ( ! undulations ( light1 are ! mo/ spl5did memorials ( our illu/ri\s c\ntryman ,dr4 ,?omas ,"y1 ?\gh ,huyg5s 0 ! fir/ to orig9ate ! idea4 ,x is suppos$ t ! p>ticles ( lum9\s bodies are 9 a /ate ( p]petual agitation1 & t !y possess ! prop]ty ( excit+ regul> vibrations 9 ! molecules ( ! e!real m$ium1 correspond+ to ! vibrations ( _! own molecules2 & t1 on acc\nt ( its ela/ic nature1 "o p>ticle ( ! e!r :5 set 9 motion communicates its vibrations to ^? adjac5t1 :i* 9 succession transmit !m to ^? f>!r (f2 s t ! primitive impulse is transf]r$ f p>ticle to p>ticle1 & ! undulat+ motion d>ts ?r\gh e!r l a wave 9 wat]2 s t light is motion1 & !re=e subject to ! laws ( dynamics & ma!matical analysis4 ,al?\gh ! progressive motion ( light is kn[n by exp]i5ce to be uni=m & 9 a /raight l9e1 ! vibrations ( ! p>ticles are always at "r angles to ! direction ( ! ray4 ,! propagation ( light is l ! spread+ ( waves 9 wat]2 b1 if "o ray alone be consid]$1 its motion may be conceiv$ by suppos+ a rope ( indef9ite l5g? /ret*$ horizontally1 "o end ( :i* is held 9 ! h&4 ,if x be agitat$ to & fro at regul> int]vals1 ) a motion p]p5dicul> to its l5g?1 a s]ies ( simil> & equal tremors or waves w be propagat$ along x2 & if ! regul> impulses be giv5 9 a v>iety ( planes1 z up & d[n1 f "r to left1 & also 9 oblique directions1 ! successive undulations w take place 9 e possible plane4 ,an analog\s motion 9 ! e!r1 :5 communicat$ to ! optic n]ves1 w\ld produce ! s5sation ( common light4 ,x is evid5t t ! waves :i* fl[ f end to end ( ! cord 9 a s]p5t9e =m are altoge!r diff]5t f ! p]p5dicul> vibratory motion ( ea* p>ticle ( ! rope1 :i* nev] deviates f> f a /ate ( re/4 ,s1 9 e!r1 ea* p>ticle vibrates p]p5dicul>ly to ! direction ( ! ray2 b ^! vibrations are totally diff]5t f & indep5d5t ( ! undulations :i* are transmitt$ ?r\gh x1 9 ! same mann] z ! vibrations ( ea* p>ticul> e> ( corn are indep5d5t ( ! waves t ru% f end to end ( a h>ve/-field :5 agitat$ by ! w9d4 ,! int5sity ( light dep5ds ^u ! amplitude or ext5t ( ! vibrations ( ! p>ticles ( e!r1 :ile its col\r dep5ds ^u _! frequ5cy4 ,! "t ( ! vibration ( a p>ticle ( e!r is1 by !ory1 z ! l5g? ( a wave directly1 & inv]sely z its velocity4 ,n[1 z ! velocity ( light is kn[n to be #aij1jjj miles 9 a second1 if ! l5g?s ( ! waves ( ! diff]5t col\r$ rays c\ld be measur$1 ! numb] ( vibrations 9 a second correspond+ to ea* c\ld be comput$4 ,t has be5 accompli%$ z foll[s3--,all transp>5t sub/ances ( a c]ta9 ?ickness1 ) p>allel surfaces1 reflect & transmit :ite light2 b1 if !y be extremely ?91 bo? ! reflect$ & transmitt$ light is col\r$4 ,! vivid hues on soap-bubbles1 ! iridesc5t col\rs produc$ by heat on poli%$ /eel & copp]1 ! fr+es ( col\r betwe5 ! lam9 ( ,icel& sp> & sulphate ( lime1 all consi/ ( a succession ( hues dispos$ 9 ! same ord]1 totally indep5d5t ( ! col\r ( ! sub/ance1 & det]m9$ solely by its great] or less ?ickness--a circum/ance :i* af=ds ! means ( asc]ta9+ ! l5g? ( ! waves ( ea* col\r$ ray1 & ! frequ5cy ( ! vibrations ( ! p>ticles produc+ !m4 ,if a plate ( glass be laid ^u a l5s ( almo/ imp]ceptible curvature1 be=e an op5 w9d[1 :5 !y are press$ toge!r a black spot w be se5 9 ! po9t ( contact1 surr\nd$ by sev5 r+s ( vivid col\rs1 all diff]+ f "o ano!r 7,n4 #aii74 ,9 ! fir/ r+1 e/imat$ f ! black spot1 ! col\rs succe$ ea* o!r 9 ! foll[+ ord]3--black1 v fa9t blue1 brilliant :ite1 yell[1 orange1 & r$4 ,!y are q diff]5t 9 ! o!r r+s1 & 9 ! sev5? ! only col\rs are pale blui% gre5 & v pale p9k4 ,t ^! r+s are =m$ betwe5 ! two surfaces 9 app>5t contact may be prov$ by lay+ a prism on ! l5s in/ead ( ! plate ( glass1 & view+ ! r+s ?r\gh ! incl9$ side ( x t is next to ! eye1 :i* arrangem5t prev5ts ! light reflect$ f ! upp] surface mix+ ) t f ! surfaces 9 contact1 s t ! int]vals betwe5 ! r+s appe> p]fectly black--"o ( ! /ronge/ circum/ances 9 fav\r ( ! undulatory !ory2 =1 al?\gh ! ph5om5a ( ! r+s c be expla9$ by ei!r hypo!sis1 !re is ?is mat]ial diff]5ce1 t1 accord+ to ! undulatory !ory1 ! int]vals betwe5 ! r+s ought to be absolutely black1 :i* is confirm$ by exp]im5t2 :]eas1 by ! doctr9e ( emanation1 !y ought to be half illum9at$1 :i* is n f\nd to be ! case4 ,m4 ,fresnel1 ^: op9ion is ( ! fir/ au?ority1 ?\ght ?is te/ conclusive4 ,x may !re=e be conclud$ t ! r+s arise entirely f ! int]f]5ce ( ! rays3 ! light reflect$ f ea* ( ! surfaces 9 app>5t contact rea*es ! eye by pa?s ( diff]5t l5g?s1 & produces col\r$ & d>k r+s alt]nately1 accord+ z ! reflect$ waves co9cide or de/roy "o ano!r4 ,! bread?s ( ! r+s are unequal2 !y decrease 9 wid?1 & ! col\rs become m cr[d$1 z !y rec$e f ! c5tre4 ,col\r$ r+s are also produc$ by transmitt+ light ?r\gh ! same app>atus2 b ! col\rs are less vivid1 & are complem5t>y to ^? reflect$1 consequ5tly ! c5tral spot is :ite4 ,! size ( ! r+s increases ) ! obliquity ( ! incid5t light1 ! same col\r requir+ a great] ?ickness or space betwe5 ! glasses to produce x ?an :5 ! light falls p]p5dicul>ly ^u !m4 ,n[1 if ! app>atus be plac$ 9 homog5e\s in/ead ( :ite light1 ! r+s w all be ( ! same col\r ) t ( ! light employ$1 t is to say1 if ! light be r$1 ! r+s w be r$1 divid$ by black int]vals4 ,! size ( ! r+s v>ies ) ! col\r ( ! light4 ,!y are l>ge/ 9 r$1 & decrease 9 magnitude ) ! succe$+ prismatic col\rs1 be+ smalle/ 9 violet light4 ,s9ce "o ( ! glasses is plane & ! o!r sph]ical1 x is evid5t t f ! po9t ( contact ! space betwe5 !m gradually increases 9 ?ickness all r\nd1 s t a c]ta9 ?ickness ( air corresponds to ea* col\r1 :i* 9 ! undulatory sy/em measures ! l5g? ( ! wave produc+ x 7,n4 #bjj74 ,by actual measurem5t ,sir ,isaac ,newton f\nd t ! squ>es ( ! diamet]s ( ! brighte/ "p ( ea* r+ are z ! odd numb]s1 #a1 #c1 #e1 #g1 c42 & t ! squ>es ( ! diamet]s ( ! d>ke/ p>ts are z ! ev5 numb]s1 #j1 #b1 #d1 #f1 c4 ,consequ5tly1 ! int]vals betwe5 ! glasses at ^! po9ts are 9 ! same proportion4 ,if1 !n1 ! ?ickness ( ! air correspond+ to any "o col\r c\ld be f\nd1 its ?ickness = all ! o!rs w\ld be kn[n4 ,n[1 z ,sir ,isaac ,newton knew ! radius ( curvature ( ! l5s1 & ! actual bread? ( ! r+s 9 p>ts ( an in*1 x 0 easy to compute t ! ?ickness ( air at ! d>ke/ "p ( ! fir/ r+ is ! #a_/hijjj "p ( an in*1 :5ce all ! o!rs h be5 d$uc$4 ,z ^! int]vals det]m9e ! l5g? ( ! waves on ! undulatory hypo!sis1 x appe>s t ! l5g? ( a wave ( ! extreme r$ ( ! sol> spectrum is equal to ! #jjjjjbff? "p ( an in*2 t ! l5g? ( a wave ( ! extreme violet is equal to ! #jjjjjafg? "p ( an in*2 &1 z ! "t ( a vibration ( a p>ticle ( e!r produc+ any p>ticul> col\r is directly z ! l5g? ( a wave ( t col\r1 & inv]sely z ! velocity ( light1 x foll[s t ! molecules ( e!r produc+ ! extreme r$ ( ! sol> spectrum p]=m #deh millions ( millions ( vibrations 9 a second2 & t ^? produc+ ! extreme violet accompli% #gbg millions ( millions ( vibrations 9 ! same "t4 ,! l5g?s ( ! waves ( ! int]m$iate col\rs1 & ! numb] ( _! vibrations1 be+ int]m$iate betwe5 ^! two1 :ite light1 :i* consi/s ( all ! col\rs1 is consequ5tly a mixture ( waves ( all l5g?s betwe5 ! limits ( ! extreme r$ & violet4 ,! det]m9ation ( ^! m9ute portions ( "t & space1 bo? ( :i* h a real exi/5ce1 be+ ! actual results ( measurem5t1 d z mu* hon\r to ! g5ius ( ,newton z t ( ! law ( gravitation4 ,! numb] ( advanc+ waves ( light 9 an in* is kn[n to be f #cg1fjj to #ei1hhj1 & ! numb] ( lat]al vibrations is f #deh to #gbg billions 9 a second1 b ! ext5t ( ^! lat]al vibrations ( ! p>ticles ( ! e!real m$ium is n kn[n1 ?\gh bo? _! ext5t & velocity are probably v small comp>$ ) ! l5g? ( ! advanc+ waves & ! velocity ( propagation4 ,col\r is id5tifi$ ) ! numb] ( vibrations2 b :e!r reflection1 refraction1 absorption1 c41 h any relations to ! lat]al vibrations1 or :e!r !y are dep5d5t 9 "p ^u "s physical action ( ! e!real m$ium unkn[n & unsuspect$1 are po9ts z yet undet]m9$4 ,to asc]ta9 ^! circum/ances1 ,dr4 ,f>aday in/itut$ a s]ies ( ! mo/ ref9$ exp]im5ts ^u ! relation ( ! m9ute p>ticles ( metals to ! vibrations ( light4 ,gold acts p[]fully on light1 & possesses a real transp>5cy1 transmitt+ gre5 rays :5 v ?92 & be+ capable ( extreme division by solv5ts )\t los+ its metallic "*1 its p>ticles transmit rays ( v>i\s col\rs accord+ to _! size2 ^? t transmit ! rose-col\r 9 ,bohemian glass are ( inconceivable m9ut5ess4 ,! progressive waves ( ! e!r are s long comp>$ ) ! dim5sions ( ! molecules to :i* gold c be r$uc$1 t x seem$ probable to ,dr4 ,f>aday :5 ! latt] 7 plac$ 9 a sunbeam t "s effective relation might be discov]$ betwe5 !m & ! small] vibrations ( ! e!real m$ium2 9 :i* case1 if reflection1 refraction1 c41 dep5d$ ^u su* relations1 !re 0 reason to expect t ^! functions w\ld *ange s5sibly by ! sub/itution ( diff]5t siz$ p>ticles ( ! gold = "o ano!r4 ,at "o "t ,dr4 ,f>aday hop$ he _h *ang$ "o col\r into ano!r by means ( gold1 :i* w\ld h be5 equival5t to a *ange 9 ! numb] ( vibrations2 b al?\gh he has n yet confirm$ t result1 8 rese>*es are ( ! greate/ int]e/4#i ,! ph5om5on ( ! col\r$ r+s takes place 9 vacuo z well z 9 air1 :i* proves t x is ! di/ance betwe5 ! l5ses alone1 & n ! air1 :i* produces ! col\rs4 ,h[ev]1 if wat] or oil be put betwe5 !m1 ! r+s contract1 b no o!r *ange ensues2 & ,newton f\nd t ! ?ickness ( diff]5t m$ia at :i* a giv5 t9t is se5 is 9 ! inv]se ratio ( _! refractive indices1 s t ! ?ickness ( lam9 :i* c\ld n o!rwise be measur$ may be kn[n by _! col\r2 &1 z ! position ( ! col\rs 9 ! r+s is inv>iable1 !y =m a fix$ /&>d ( comp>ison1 well kn[n z ,newton's scale ( col\rs2 ea* t9t be+ e/imat$ accord+ to ! r+ to :i* x belongs f ! c5tral spot inclusively4 ,n only ! p]iodical col\rs :i* h be5 describ$1 b ! col\rs se5 9 ?ick plates ( transp>5t sub/ances1 ! v>iable hues ( fea!rs1 ( insects' w+s1 "m-(-pe>l1 & ( /riat$ sub/ances1 all dep5d ^u ! same pr9ciple4 ,to ^! may be add$ ! col\r$ fr+es surr\nd+ ! %ad[s ( all bodies held 9 an extremely small beam ( light1 & ! col\r$ r+s surr\nd+ ! small beam itself :5 receiv$ on a scre54 ,:5 a v sl5d] sunbeam1 pass+ ?r\gh a small p9-hole into a d>k room1 is receiv$ on a :ite scre51 or plate ( gr\nd-glass1 at ! di/ance ( a little m ?an six feet1 ! spot ( light on ! scre5 is l>g] ?an ! p9-hole3 &1 in/ead ( be+ b\nd$ by %ad[1 x is surr\nd$ by a s]ies ( col\r$ r+s sep>at$ by obscure int]vals4 ,! r+s are m di/9ct 9 proportion to ! smallness ( ! beam 7,n4 #bja74 ,:5 ! light is :ite !re are sev5 r+s1 :i* dilate or contract ) ! di/ance ( ! scre5 f ! hole4 ,z ! di/ance ( ! scre5 dim9i%es1 ! :ite c5tral spot contracts to a po9t & vani%es2 &1 on approa*+ /ill ne>]1 ! r+s gradually close 9 ^u x1 s t ! c5tre assumes successively ! mo/ int5se & vivid hues4 ,:5 ! light is homog5e\s--r$1 = example--! r+s are alt]nately r$ & black1 & m num]\s2 & _! bread? v>ies ) ! col\r1 be+ broade/ 9 r$ light & n>r[e/ 9 violet4 ,! t9ts ( ! col\r$ fr+es f :ite light1 & _! oblit]ation aft] ! sev5? r+1 arise f ! sup]position ( ! diff]5t sets ( fr+es ( all ! col\r$ rays4 ,! %ad[s ( objects are also bord]$ by col\r$ fr+es :5 held 9 ?is sl5d] beam ( light4 ,if ! edge ( a knife or hair1 = example1 be held 9 x1 ! rays1 in/ead ( proce$+ 9 /raight l9es pa/ its edge1 are b5t :5 q close to x1 & proce$ f !nce to ! scre5 9 curv$ l9es call$ hyp]bolas2 s t ! %ad[ ( ! object is enl>g$1 &1 in/ead ( be+ at once b\nd$ by light1 is surr\nd$ or edg$ ) col\r$ fr+es alt]nat+ ) black b&s1 :i* are m di/9ct ! small] ! p9-hole 7,n4 #bjb74 ,! fr+es are altoge!r indep5d5t ( ! =m or d5sity ( ! object1 be+ ! same :5 x is r\nd or po9t$1 :5 ( glass or plat9um4 ,:5 ! rays :i* =m ! fr+es arrive at ! scre51 !y are ( diff]5t l5g?s1 9 consequ5ce ( ! curv$ pa? !y foll[ aft] pass+ ! edge ( ! object4 ,! waves are !re=e 9 diff]5t phases or /ates ( vibration1 & ei!r conspire to =m col\r$ fr+es or de/roy "o ano!r 9 ! obscure int]vals4 ,! col\r$ fr+es bord]+ ! %ad[s ( objects 7 fir/ describ$ by ,grimaldi 9 #affe2 b1 besides ^!1 he notic$ t !re are o!rs )9 ! %ad[s ( sl5d] bodies expos$ to a small sunbeam1 a ph5om5on :i* has already be5 m5tion$ to h af=d$ ,dr4 ,"y ! means ( prov+1 beyond all controv]sy1 t col\r$ r+s are produc$ by ! int]f]5ce ( light4 ,x may be conclud$ t mat]ial sub/ances d]ive _! col\rs f two diff]5t causes3 "s f ! law ( int]f]5ce1 su* z iridesc5t metals1 peacocks' fea!rs1 c42 o!rs f ! unequal absorption ( ! rays ( :ite light1 su* z v]milion1 ultram>9e1 blue1 or gre5 clo?1 fl[]s1 & ! great] numb] ( col\r$ bodies4 ,! latt] ph5om5a h be5 consid]$ extremely difficult to reconcile ) ! undulatory !ory ( light1 & mu* discussion has aris5 z to :at becomes ( ! absorb$ rays4 ,b t emb>rass+ "q has be5 ably answ]$ by ,sir ,john ,h]s*el 9 a mo/ pr(\nd pap] on ! ,absorption ( ,light by col\r$ ,m$ia1 & _c be bett] giv5 ?an 9 8 own words4 ,x mu/1 h[ev]1 be premis$1 t1 z all transp>5t bodies are trav]s$ by light1 !y are presum$ to be p]meable to ! e!r4 ,he says1--8,n[1 z reg>ds only ! g5]al fact ( ! ob/ruction & ultimate ext9ction ( light 9 its passage ?r\gh gross m$ia1 if we comp>e ! corpuscul> & undulatory !ories1 we %all f9d t ! =m] appeals to our ignorance1 ! latt] to our k1 = its explanation ( ! absorptive ph5om5a4 ,9 attempt+ to expla9 ! ext9ction ( light on ! corpuscul> doctr9e1 we h to acc\nt = ! light s ext+ui%$ z a mat]ial body1 :i* we mu/ n suppose annihilat$4 ,x may1 h[ev]1 be trans=m$2 & among ! impond]able ag5ts1 heat1 electricity1 c41 x may be t we are to se>* = ! light :i* has become ?us comp>atively /agnant4 ,! heat+ p[] ( ! sol> rays gives a prim facie plausibility to ! idea ( ! trans=mation ( light into heat by absorption4 ,b1 :5 we come to exam9e ! matt] m ne>ly1 we f9d x encumb]$ on all sides ) difficulties4 ,h[ is x1 = in/ance1 t ! mo/ lum9\s rays are n ! mo/ calorific1 b t1 on ! contr>y1 ! calorific en]gy accompanies1 9 its greate/ int5sity1 rays :i* possess comp>atively feeble illum9at+ p[]s8 ,^! & o!r que/ions ( a simil> nature may p]haps admit ( answ] 9 a m advanc$ /ate ( our k2 b at pres5t !re is none obvi\s4 ,x is n )\t reason1 !re=e1 t ! "q1 #8,:at becomes ( light8' :i* appe>s to h be5 agitat$ among ! photologi/s ( ! la/ c5tury1 has be5 reg>d$ z "o ( consid]able importance z well z obscurity by ! corpuscul> philosoph]s4 ,on ! o!r h&1 ! answ] to ?is "q1 af=d$ by ! undulatory !ory ( light1 is simple & di/9ct4 ,! "q1 #8,:at becomes ( light8' m]ges 9 ! m g5]al "o1 #8,:at becomes ( motion8' ,& ! answ]1 on dynamical pr9ciples1 is1 t x cont9ues = ev]4 ,no motion is1 /rictly speak+1 annihilat$2 b x may be divid$1 & ! divid$ p>ts made to oppose & 9 effect de/roy "o ano!r4 ,a body /ruck1 h[ev] p]fectly ela/ic1 vibrates = a "t1 & !n appe>s to s9k into its orig9al repose4 ,b ?is app>5t re/ 7ev5 ab/ract+ f ! inquiry t "p ( ! motion :i* may be convey$ away by ! ambi5t air7 is no?+ else ?an a /ate ( subdivid$ & mutually de/roy+ motion1 9 :i* e molecule cont9ues to be agitat$ by an indef9ite multitude ( int]nally reflect$ waves1 propagat$ ?r\gh x 9 e possible direction1 f e po9t 9 its surface on :i* !y successively imp+e4 ,! sup]position ( su* waves w1 x is easily se51 at l5g? op]ate _! mutual de/ruction1 :i* w be ! m complete ! m irregul> ! figure ( ! body1 & ! great] ! numb] ( int]nal reflections40 ,?us ,sir ,john ,h]s*el1 by ref]r+ ! absorption ( light to ! subdivision & mutual de/ruction ( ! vibrations ( e!r 9 ! int]ior ( bodies1 br+s ano!r class ( ph5om5a "u ! laws ( ! undulatory !ory4 ,accord+ to ,mr4 ,rank9's hypo!sis ( ,molecul> ,vortices#aj ! absorption ( light & radiant heat consi/s 9 ! transf]5ce ( motion f ! molecules to _! atmosph]es1 & conv]sely ! emission ( light & radiant heat is ! transmission ( motion f ! atmosph]es to ! molecules4 ,! great velocity ( light & heat is a natural consequ5ce ( ?is hypo!sis1 accord+ to :i* ! vibratory masses mu/ be extremely small comp>$ ) ! =ces ex]t$ by !m4 ,! e!real m$ium p]vad+ space is suppos$ to p5etrate all mat]ial sub/ances1 occupy+ ! int]/ices betwe5 _! molecules2 b 9 ! int]ior ( refract+ m$ia x exi/s 9 a /ate ( less ela/icity comp>$ ) its d5sity 9 vacuo2 &1 ! m refractive ! m$ium1 ! less ! ela/icity ( ! e!r )9 x4 ,h5ce ! waves ( light are transmitt$ ) less velocity 9 su* m$ia z glass & wat] ?an 9 ! ext]nal e!r4 ,z soon z a ray ( light rea*es ! surface ( a diaphan\s reflect+ sub/ance1 = example a plate ( glass1 x communicates its undulations to ! e!r next 9 contact ) ! surface1 :i* ?us becomes a new c5tre ( motion1 & two hemisph]ical waves are propagat$ f ea* po9t ( ?is surface2 "o ( :i* proce$s =w>d into ! int]ior ( ! glass1 ) a less velocity ?an ! incid5t waves2 & ! o!r is transmitt$ back into ! air1 ) a velocity equal to t ) :i* x came 7,n4 #bjc74 ,?us1 :5 refract$1 ! light moves ) a diff]5t velocity )\t & )9 ! glass2 :5 reflect$1 ! ray comes & goes ) ! same velocity4 ,! p>ticles ( e!r )\t ! glass1 :i* communicate _! motions to ! p>ticles ( ! d5se & less ela/ic e!r )9 x1 are analog\s to small ela/ic balls /rik+ l>ge ones2 = "s ( ! motion w be communicat$ to ! l>ge balls1 & ! small ones w be reflect$4 ,! fir/ w\ld cause ! refract$ wave1 & ! la/ ! reflect$4 ,conv]sely1 :5 ! light passes f glass to air1 ! action is simil> to l>ge balls /rik+ small ones4 ,! small balls receive a motion :i* w\ld cause ! refract$ ray1 & ! "p ( ! motion reta9$ by ! l>ge ones w\ld occasion ! reflect$ wave2 s t1 :5 light passes ?r\gh a plate ( glass or ( any o!r m$ium diff]+ 9 d5sity f ! air1 !re is a reflection at bo? surfaces2 b ?is diff]5ce exi/s betwe5 ! two reflections1 t "o is caus$ by a vibration 9 ! same direction ) t ( ! incid5t ray1 & ! o!r by a vibration 9 ! opposite direction4 ,a s+le wave ( air or e!r w\ld n produce ! s5sation ( s\nd or light4 ,9 ord] to excite vision1 ! vibrations ( ! molecules ( e!r mu/ be regul>1 p]iodical1 & v (t5 repeat$3 &1 z ! e> cont9ues to be agitat$ = a %ort "t aft] ! impulse by :i* alone a s\nd becomes cont9u\s1 s also ! fibres ( ! ret9a1 accord+ to ,m4 d',arcet1 cont9ue to vibrate = ab\t ! eigh? "p ( a second aft] ! excit+ cause has ceas$4 ,! int]val ( "t dur+ :i* ! impression la/s is long] = ! blue ?an = r$ or :ite light3 x mu/ n be less ?an #jcd4 ,e "o mu/ h obs]v$1 :5 a /rong impression is made by a bright light1 t an object rema9s visible = a %ort "t aft] %utt+ ! eyes1 :i* is suppos$ to be 9 consequ5ce ( ! cont9u$ vibrations ( ! fibres ( ! ret9a4 ,occasionally ! ret9a becomes ins5sible to feebly illum9at$ objects :5 cont9u\sly pres5t$4 ,if ! eye be turn$ aside = a mom5t1 ! object becomes aga9 visible4 ,x is probably on ?is acc\nt t ! owl makes s peculi> a motion ) its head :5 look+ at objects 9 ! twilight4 ,x is q possible t _m vibrations may be excit$ 9 ! e!real m$ium incapable ( produc+ undulations 9 ! fibres ( ! human ret9a1 :i* yet h a p[]ful effect on ^? ( o!r animals or ( insects4 ,su* may receive lum9\s impressions ( :i* we are totally unconsci\s1 & at ! same "t !y may be ins5sible to ! light & col\rs :i* affect our eyes1 _! p]ceptions beg9n+ :]e ours end4 ,,section ,,xxi4 ,pol>ization ( ,light--,def9$--,pol>ization by ,refraction--,prop]ties ( ! ,t\rmal9e--,d\ble ,refraction--,all d\bly ,refract$ ,light is ,pol>iz$--,prop]ties ( ,icel& ,sp>--,t\rmal9e absorbs "o ( ! two ,refract$ ,rays--,undulations ( ,natural ,light--,undulations ( ,pol>iz$ ,light--,! ,optic ,axes ( ,cry/als--,m4 ,fresnel's ,discov]ies on ! ,rays pass+ along ! ,optic ,axis--,pol>ization by ,reflection4 ,,9 giv+ a sket* ( ! con/itution ( light1 x is impossible to omit ! extraord9>y prop]ty ( its pol>ization1 8! ph5om5a ( :i*10 ,sir ,john ,h]s*el says1 8are s s+ul> & v>i\s1 t to "o :o has only /udi$ ! common bran*es ( physical optics x is l ent]+ into a new _w1 s spl5did z to r5d] x "o ( ! mo/ delightful bran*es ( exp]im5tal inquiry1 & s f]tile 9 ! views x lays op5 ( ! con/itution ( natural bodies1 & ! m9ut] me*anism ( ! univ]se1 z to place x 9 ! v fir/ rank ( ! physico-ma!matical sci5ces1 :i* x ma9ta9s by ! rigor\s application ( geometrical reason+ its nature admits & requires40 ,light is said to be pol>iz$1 :i*1 by be+ once reflect$ or refract$1 is r5d]$ incapable ( be+ aga9 reflect$ or refract$ at c]ta9 angles4 ,9 g5]al1 :5 a ray ( light is reflect$ f a pane ( plate-glass1 or any o!r sub/ance1 x may be reflect$ a second "t f ano!r surface1 & x w also pass freely ?r\gh transp>5t bodies4 ,b1 if a ray ( light be reflect$ f a pane ( plate-glass at an angle ( #eg1 x is r5d]$ totally incapable ( reflection at ! surface ( ano!r pane ( glass 9 c]ta9 def9ite positions1 b x w be completely reflect$ by ! second pane 9 o!r positions4 ,x likewise loses ! prop]ty ( p5etrat+ transp>5t bodies 9 p>ticul> positions1 :il/ x is freely transmitt$ by !m 9 o!rs4 ,light1 s modifi$ z to be incapable ( reflection & transmission 9 c]ta9 directions1 is said to be pol>iz$4 ,light may be pol>iz$ by reflection f any poli%$ surface1 & ! same prop]ty is also imp>t$ by refraction4 ,x is propos$ to expla9 ^! me?ods ( pol>iz+ light1 to give a %ort acc\nt ( its mo/ rem>kable prop]ties1 & to endeav\r to describe a few ( ! spl5did ph5om5a x exhibits4 ,if a br[n t\rmal9e1 :i* is a m9]al g5]ally cry/alliz$ 9 ! =m ( a long prism1 be cut longitud9ally1 t is1 p>allel to ! axis ( ! prism1 into plates ab\t ! ?irtie? ( an in* 9 ?ickness1 & ! surfaces poli%$1 lum9\s objects may be se5 ?r\gh !m1 z ?r\gh plates ( col\r$ glass4 ,! axis ( ea* plate is 9 its longitud9al section p>allel to ! axis ( ! prism :5ce x 0 cut 7,n4 #bjd74 ,if "o ( ^! plates be held p]p5dicul>ly betwe5 ! eye & a c&le1 & turn$ sl[ly r\nd 9 its own plane1 no *ange w take place 9 ! image ( ! c&le4 ,b if ! plate be held 9 a fix$ position1 ) its axis or longitud9al section v]tical1 :5 a second plate ( t\rmal9e is int]pos$ betwe5 x & ! eye1 p>allel to ! fir/1 & turn$ sl[ly r\nd 9 its own plane1 a rem>kable *ange w be f\nd to h tak5 place 9 ! nature ( ! light4 ,= ! image ( ! c&le w vani% & appe> alt]nately at e qu>t] revolution ( ! plate1 v>y+ ?r\gh all degrees ( brightness d[n to total or almo/ total evanesc5ce1 & !n increas+ aga9 by ! same degrees z x _h be=e decreas$4 ,^! *anges dep5d ^u ! relative positions ( ! plates4 ,:5 ! longitud9al sections ( ! two plates are p>allel1 ! brightness ( ! image is at its maximum2 &1 :5 ! axes ( ! sections cross at "r angles1 ! image ( ! c&le vani%es4 ,?us ! light1 9 pass+ ?r\gh ! fir/ plate ( t\rmal9e1 has acquir$ a prop]ty totally diff]5t f ! direct light ( ! c&le4 ,! direct light w\ld h p5etrat$ ! second plate equally well 9 all directions1 :]eas ! refract$ ray w only pass ?r\gh x 9 p>ticul> positions1 & is altoge!r incapable ( p5etrat+ x 9 o!rs4 ,! refract$ ray is pol>iz$ 9 its passage ?r\gh ! fir/ t\rmal9e1 & exp]i5ce %[s t x nev] loses t prop]ty1 unless :5 act$ ^u by a new sub/ance4 ,?us1 "o ( ! prop]ties ( pol>iz$ light is ! incapability ( pass+ ?r\gh a plate ( t\rmal9e p]p5dicul> to x1 9 c]ta9 positions1 & its ready transmission 9 o!r positions at "r angles to ! =m]4 ,_m o!r sub/ances h ! prop]ty ( pol>iz+ light4 ,if a ray ( light falls ^u a transp>5t m$ium1 :i* has ! same temp]ature1 d5sity1 & /ructure ?r\gh\t e "p1 z fluids1 gases1 glass1 c41 & a few regul>ly cry/alliz$ m9]als1 x is refract$ into a s+le p5cil ( light by ! laws ( ord9>y refraction1 accord+ to :i* ! ray1 pass+ ?r\gh ! refract+ surface f ! object to ! eye1 nev] quits a plane p]p5dicul> to t surface4 ,almo/ all o!r bodies1 su* z ! great] numb] ( cry/alliz$ m9]als1 animal & vegetable sub/ances1 gums1 res9s1 jellies1 & all solid bodies hav+ unequal t5sions1 :e!r f unequal temp]ature or pressure1 possess ! prop]ty ( d\bl+ ! image or appe>ance ( an object se5 ?r\gh !m 9 c]ta9 directions2 because a ray ( natural light fall+ ^u !m is refract$ into two p5cils :i* move ) diff]5t velocities1 & are m or less sep>at$1 accord+ to ! nature ( ! body & ! direction ( ! incid5t ray4 ,:5ev] a ray ( natural light is ?us divid$ into two p5cils 9 its passage ?r\gh a sub/ance1 bo? ( ! transmitt$ rays are pol>iz$4 ,icel& sp>1 a c>bonate ( lime1 :i* by its natural cleavage may be split into ! =m ( a rhomboh$ron1 possesses ! prop]ty ( d\ble refraction 9 an em95t degree1 z may be se5 by pa/+ a piece ( pap]1 ) a l>ge p9-hole 9 x1 on ! side ( ! sp> f>!/ f ! eye4 ,! hole w appe> d\ble :5 held to ! light 7,n4 #bje74 ,"o ( ^! p5cils is refract$ accord+ to ! same law z 9 glass or wat]1 nev] quitt+ ! plane p]p5dicul> to ! refract+ surface1 & is !re=e call$ ! ord9>y ray4 ,b ! o!r does quit ! plane1 be+ refract$ accord+ to a diff]5t & mu* m complicat$ law1 & on t acc\nt is call$ ! extraord9>y ray4 ,= ! same reason "o image is call$ ! ord9>y1 & ! o!r ! extraord9>y image4 ,:5 ! sp> is turn$ r\nd 9 ! same plane1 ! extraord9>y image ( ! hole revolves ab\t ! ord9>y image1 :i* rema9s fix$1 bo? be+ equally bright4 ,b if ! sp> be kept 9 "o position1 & view$ ?r\gh a plate ( t\rmal9e1 x w be f\nd t1 z ! t\rmal9e revolves1 ! images v>y 9 _! relative brightness--"o increases 9 int5sity till x arrives at a maximum1 at ! same "t t ! o!r dim9i%es till x vani%es1 & s on alt]nately at ea* qu>t] revolution1 prov+ bo? rays to be pol>iz$4 ,= 9 "o position ! t\rmal9e transmits ! ord9>y ray1 & reflects ! extraord9>y2 &1 aft] revolv+ #ij1 ! extraord9>y ray is transmitt$1 & ! ord9>y ray is reflect$4 ,?us ano!r prop]ty ( pol>iz$ light is1 t x _c be divid$ into two equal p5cils by d\ble refraction1 9 positions ( ! d\bly refract+ bodies 9 :i* a ray ( common light w\ld be s divid$4 ,7 t\rmal9e l o!r d\bly refract+ bodies1 ea* ( ! transmitt$ rays w\ld be d\ble2 b t m9]al1 :5 ( a c]ta9 ?ickness1 aft] sep>at+ ! light into two pol>iz$ p5cils1 absorbs t :i* und]goes ord9>y refraction1 & consequ5tly %[s only "o image ( an object4 ,on ?is acc\nt t\rmal9e is peculi>ly fitt$ = analyz+ pol>iz$ light1 :i* %[s no?+ rem>kable till view$ ?r\gh x or some?+ equival5t4 ,! p5cils ( light1 on leav+ a d\ble refract+ sub/ance1 are p>allel2 & x is cle>1 f ! prec$+ exp]im5ts1 t !y are pol>iz$ 9 planes at "r angles to ea* o!r 7,n4 #bjf74 ,b t w be bett] und]/ood by consid]+ ! *ange produc$ 9 common light by ! action ( ! pol>iz+ body4 ,x has be5 %[n t ! undulations ( e!r1 :i* produce ! s5sation ( common light1 are p]=m$ 9 e possible plane1 at "r angles to ! direction 9 :i* ! ray is mov+4 ,b ! case is v diff]5t aft] ! ray has pass$ ?r\gh a d\bly refract+ sub/ance1 l ,icel& sp>4 ,! light !n proce$s 9 two p>allel p5cils1 ^: undulations are /ill inde$ transv]se to ! direction ( ! rays1 b !y are accompli%$ 9 planes at "r angles to "o ano!r1 analog\s to two p>allel /ret*$ cords1 "o ( :i* p]=ms its undulations only 9 a horizontal plane1 & ! o!r 9 a v]tical or upright plane 7,n4 #bjf74 ,?us ! pol>iz+ action ( ,icel& sp> & ( all d\bly refract+ sub/ances is to sep>ate a ray ( common light1 ^: waves or undulations are 9 e plane1 into two p>allel rays1 ^: waves or undulations lie 9 planes at "r angles to ea* o!r4 ,by a simple me*anical law ea* vibratory motion ( ! fir/ is resolv$ into two vibratory motions at "r angles to "o ano!r4 ,! ray ( common light may be assimilat$ to a r\nd rod1 :]eas ! two pol>iz$ rays are l two p>allel long flat rul]s1 "o ( :i* is laid horizontally on its broad surface1 & ! o!r horizontally on its edge4 ,! alt]nate transmission & ob/ruction ( "o ( ^! flatt5$ beams by ! t\rmal9e is simil> to ! facility ) :i* a c>d may be pass$ betwe5 ! b>s ( a grat+ or wires ( a cage1 if pres5t$ edgeways1 & ! impossibility ( its pass+ 9 a transv]se direction4 ,al?\gh x g5]ally happ5s t a ray ( light1 9 pass+ ?r\gh ,icel& sp>1 is sep>at$ into two pol>iz$ rays1 yet !re is "o direction along :i* x is refract$ 9 "o ray only1 & t accord+ to ! ord9>y law4 ,?is direction is call$ ! optic axis 7,n4 #bjg74 ,_m cry/als & o!r sub/ances h two optic axes1 incl9$ to ea* o!r1 along :i* a ray ( light is transmitt$ 9 "o p5cil by ! law ( ord9>y refraction4 ,! extraord9>y ray is sometimes refract$ t[>ds ! optic axis1 z 9 qu>tz1 zircon1 ice1 c41 :i* are !re=e said to be positive cry/als2 b :5 x is b5t f ! optic axis1 z 9 ,icel& sp>1 t\rmal9e1 em]ald1 b]yl1 c41 ! cry/als are negative1 :i* is ! mo/ num]\s class4 ,! ord9>y ray moves ) uni=m velocity )9 a d\bly refract+ sub/ance1 b ! velocity ( ! extraord9>y ray v>ies ) ! position ( ! ray relatively to ! optic axis1 be+ a maximum :5 its motion )9 ! cry/al is at "r angles to ! optic axis1 & a m9imum :5 p>allel to x4 ,betwe5 ^! extremes its velocity v>ies accord+ to a det]m9ate law4 ,x _h be5 inf]r$1 f ! action ( ,icel& sp> on light1 t 9 all d\bly refract+ sub/ances "o only ( two rays is turn$ aside f ! plane ( ord9>y refraction1 :ile ! o!r foll[s ! ord9>y law2 & ! great difficulty ( obs]v+ ! ph5om5a t5d$ to confirm t op9ion4 ,m4 ,fresnel1 h[ev]1 prov$ by a mo/ pr(\nd ma!matical inquiry1 priori1 t ! extraord9>y ray mu/ be want+ 9 glass & o!r uncry/alliz$ sub/ances1 & t x mu/ necess>ily exi/ 9 c>bonate ( lime1 qu>tz1 & o!r bodies hav+ "o optic axis1 b t 9 a num]\s class ( sub/ances1 :i* possess two optic axes1 bo? rays mu/ und]go extraord9>y refraction1 & consequ5tly t bo? mu/ deviate f _! orig9al plane2 & ^! results h be5 p]fectly confirm$ by subsequ5t exp]im5ts4 ,?is !ory ( refraction1 :i* = g5]alization is p]haps only inf]ior to ! law ( gravitation1 has enroll$ ! "n ( ,fresnel among ^? :i* pass n away1 & makes 8 e>ly loss a subject ( deep regret to all :o take an int]e/ 9 ! high] pa?s ( sci5tific rese>*4 ,:5 a beam ( common light is p>tly reflect$ at1 & p>tly transmitt$ ?r\gh a transp>5t surface1 ! reflect$ & refract$ p5cils conta9 equal quantities ( pol>iz$ light1 & _! planes ( pol>ization are at "r angles to "o ano!r3 h5ce1 a pile ( panes ( glass w give a pol>iz$ beam by refraction4 ,=1 if a ray ( common light pass ?r\gh !m1 "p ( x w be pol>iz$ by ! fir/ plate1 ! second plate w pol>ize a "p ( :at passes ?r\gh x1 & ! re/ w d ! same 9 succession1 till ! :ole beam is pol>iz$1 except :at is lo/ by reflection at ! diff]5t surfaces1 or by absorption4 ,?is beam is pol>iz$ 9 a plane at "r angles to ! plane ( reflection1 t is1 at "r angles to ! plane pass+ ?r\gh ! incid5t & reflect$ ray 7,n4 #bjh74 ,by f> ! mo/ conv5i5t way ( pol>iz+ light is by reflection4 ,a plane ( plate-glass laid ^u a piece ( black clo?1 on a table at an op5 w9d[1 w appe> ( a uni=m brightness f ! reflection ( ! sky or cl\ds4 ,b if x be view$ ?r\gh a plate ( t\rmal9e1 hav+ its axis v]tical1 in/ead ( be+ illum9at$ z be=e1 x w be obscur$ by a l>ge cl\dy spot1 hav+ its c5tre q d>k1 :i* w readily be f\nd by elevat+ or depress+ ! eye1 & w only be visible :5 ! angle ( incid5ce is #eg1 t is1 :5 ! l9e f ! eye to ! c5tre ( ! black spot makes an angle ( #cc ) ! surface ( ! reflector 7,n4 #bji74 ,:5 ! t\rmal9e is turn$ r\nd 9 its own plane1 ! d>k cl\d w dim9i%1 & entirely vani% :5 ! axis ( ! t\rmal9e is horizontal1 & !n e "p ( ! surface ( ! glass w be equally illum9at$4 ,z ! t\rmal9e revolves1 ! cl\dy spot w appe> & vani% alt]nately at e qu>t] revolution4 ,?us1 :5 a ray ( light is incid5t on a pane ( plate-glass at an angle ( #eg1 ! reflect$ ray is r5d]$ incapable ( p5etrat+ a plate ( t\rmal9e ^: axis is 9 ! plane ( incid5ce4 ,consequ5tly x has acquir$ ! same "* z if x _h be5 pol>iz$ by transmission ?r\gh a plate ( t\rmal9e1 ) its axis at "r angles to ! plane ( reflection4 ,x is f\nd by exp]i5ce t ?is pol>iz$ ray is incapable ( a second reflection at c]ta9 angles & 9 c]ta9 positions ( ! incid5t plane4 ,= if ano!r pane ( plate-glass1 hav+ "o surface black5$1 be s plac$ z to make an angle ( #cc ) ! reflect$ ray1 ! image ( ! fir/ pane w be reflect$ 9 its surface1 & w be alt]nately illum9at$ & obscur$ at e qu>t] revolution ( ! black5$ pane1 accord+ z ! plane ( reflection is p>allel or p]p5dicul> to ! plane ( pol>ization4 ,s9ce ?is happ5s by :atev] means ! light has be5 pol>iz$1 x ev9ces ano!r g5]al prop]ty ( pol>iz$ light1 :i* is1 t x is incapable ( reflection 9 a plane at "r angles to ! plane ( pol>ization4 ,all reflect+ surfaces are capable ( pol>iz+ light1 b ! angle ( incid5ce at :i* x is completely pol>iz$ is diff]5t 9 ea* sub/ance 7,n4 #baj74 ,x appe>s t ! angle = plate-glass is #eg2 9 cr[n-glass x is #ef #ee1 & no ray w be completely pol>iz$ by wat] unless ! angle ( incid5ce be #ec #aa4 ,! angles at :i* diff]5t sub/ances pol>ize light are det]m9$ by a v simple & elegant law1 discov]$ by ,sir ,david ,brew/]1 8,t ! tang5t ( ! pol>iz+ angle = any m$ium is equal to ! s9e ( ! angle ( incid5ce divid$ by ! s9e ( ! angle ( refraction ( t m$ium40 ,:5ce also ! refractive p[] ev5 ( an opaque body is kn[n :5 its pol>iz+ angle has be5 det]m9$4 ,if a ray1 pol>iz$ by refraction or by reflection f any sub/ance n metallic1 be view$ ?r\gh a piece ( ,icel& sp>1 ea* image w alt]nately vani% & reappe> at e qu>t] revolution ( ! sp>1 :e!r x revolves f "r to left or f left to "r2 :i* %[s t ! prop]ties ( ! pol>iz$ ray are symmetrical on ea* side ( ! plane ( pol>ization4 ,al?\gh !re be only "o angle 9 ea* sub/ance at :i* light is completely pol>iz$ by "o reflection1 yet x may be pol>iz$ at any angle ( incid5ce by a suffici5t numb] ( reflections4 ,=1 if a ray falls ^u ! upp] surface ( a pile ( plates ( glass at an angle great] or less ?an a pol>iz+ angle1 a "p only ( ! reflect$ ray w be pol>iz$1 b a "p ( :at is transmitt$ w be pol>iz$ by reflection at ! surface ( ! second plate1 "p at ! ?ird1 & s on till ! :ole is pol>iz$4 ,?is is ! be/ app>atus2 b "o plate ( glass hav+ its inf]ior surface black5$1 or ev5 a poli%$ table1 w answ] ! purpose4 ,,section ,,xxii4 ,ph5om5a exhibit$ by ! ,passage ( ,pol>iz$ ,light ?r\gh ,mica & ,sulphate ( ,lime--,! ,col\r$ ,images produc$ by ,pol>iz$ ,light pass+ ?r\gh ,cry/als hav+ "o & two ,optic ,axes--,circul> ,pol>ization--,elliptical ,pol>ization--,discov]ies ( ,,mm4 ,biot1 ,fresnel1 & ,pr(essor ,airy--,col\r$ ,images produc$ by ! ,int]f]5ce ( ,pol>iz$ ,rays--,fluoresc5ce4 ,,su* is ! nature ( pol>iz$ light & ( ! laws x foll[s4 ,b x is h>dly possible to convey an idea ( ! spl5d\r ( ! ph5om5a x exhibits "u circum/ances :i* an attempt w n[ be made to describe4 ,if light pol>iz$ by reflection f a pane ( glass be view$ ?r\gh a plate ( t\rmal9e1 ) its longitud9al section v]tical1 an obscure cl\d1 ) its c5tre totally d>k1 w be se5 on ! glass4 ,n[1 let a plate ( mica1 uni=mly ab\t ! ?irtie? ( an in* 9 ?ickness1 be int]pos$ betwe5 ! t\rmal9e & ! glass2 ! d>k spot w in/antly vani%1 &1 in/ead ( x1 a succession ( ! mo/ gorge\s col\rs w appe>1 v>y+ ) e incl9ation ( ! mica1 f ! ri*e/ r$s1 to ! mo/ vivid gre5s1 blues1 & purples 7,n4 #baa74 ,t !y may be se5 9 p]fection1 ! mica mu/ revolve at "r angles to its own plane4 ,:5 ! mica is turn$ r\nd 9 a plane p]p5dicul> to ! pol>iz$ ray1 x w be f\nd t !re are two l9es 9 x :]e ! col\rs entirely vani%4 ,^! are ! optic axes ( ! mica1 :i* is a d\bly refract+ sub/ance1 ) two optic axes1 along :i* light is refract$ 9 "o p5cil4 ,no col\rs are visible 9 ! mica1 :atev] its position may be ) reg>d to ! pol>iz$ light1 )\t ! aid ( ! t\rmal9e1 :i* sep>ates ! transmitt$ ray into two p5cils ( col\r$ light complem5t>y to "o ano!r1 t is1 :i* tak5 toge!r w\ld make :ite light4 ,"o ( ^! x absorbs1 & transmits ! o!r2 x is !re=e call$ ! analyz+ plate4 ,! tru? ( ?is w appe> m readily if a film ( sulphate ( lime1 betwe5 ! tw5tie? & sixtie? ( an in* ?ick1 be us$ in/ead ( ! mica4 ,:5 ! film is ( uni=m ?ickness1 only "o col\r w be se5 :5 x is plac$ betwe5 ! analyz+ plate & ! reflect+ glass2 z1 = example1 r$4 ,b1 :5 ! t\rmal9e revolves1 ! r$ w vani% by degrees till ! film is col\rless2 !n x w assume a gre5 hue1 :i* w increase & arrive at its maximum :5 ! t\rmal9e has turn$ ?r\gh n9ety degrees2 aft] t1 ! gre5 w vani% & ! r$ w reappe>1 alt]nat+ at ea* quadrant4 ,?us ! t\rmal9e sep>ates ! light :i* has pass$ ?r\gh ! film into a r$ & a gre5 p5cil2 9 "o position x absorbs ! gre5 & lets ! r$ pass1 & 9 ano!r x absorbs ! r$ & transmits ! gre54 ,?is is prov$ by analyz+ ! ray ) ,icel& sp> in/ead ( t\rmal9e2 =1 s9ce ! sp> does n absorb ! light1 two images ( ! sulphate ( lime w be se51 "o r$ & ! o!r gre52 & ^! ex*ange col\rs e qu>t] revolution ( ! sp>1 ! r$ becom+ gre51 & ! gre5 r$2 &1 :]e ! images ov]lap1 ! col\r is :ite1 prov+ ! r$ & gre5 to be complem5t>y to ea* o!r4 ,! t9t dep5ds on ! ?ickness ( ! film4 ,films ( sulphate ( lime1 ! #jjjabd & #jjahah ( an in* respectively1 give :ite light 9 :atev] position !y may be held1 provid$ !y be p]p5dicul> to ! pol>iz$ ray2 b films ( int]m$iate ?ickness w give all col\rs4 ,consequ5tly1 a w$ge ( sulphate ( lime1 v>y+ 9 ?ickness betwe5 ! #jjjabd & ! #jjahah ( an in*1 w appe> to be /rip$ ) all col\rs :5 pol>iz$ light is transmitt$ ?r\gh x4 ,a *ange 9 ! incl9ation ( ! film1 :e!r ( mica or sulphate ( lime1 is evid5tly equival5t to a v>iation 9 ?ickness4 ,:5 a plate ( mica1 held z close to ! eye z possible1 at su* an incl9ation z to transmit ! pol>iz$ ray along "o ( its optic axes1 is view$ ?r\gh ! t\rmal9e ) its axis v]tical1 a mo/ spl5did appe>ance is pres5t$4 ,! cl\dy spot 9 ! direction ( ! optic axis is se5 surr\nd$ by a set ( vividly col\r$ r+s ( an oval =m1 divid$ into two unequal p>ts by a black curv$ b& pass+ ?r\gh ! cl\dy spot ab\t :i* ! r+s are =m$4 ,! o!r optic axis ( ! mica exhibits a simil> image 7,n4 #bab74 ,:5 ! two optic axes ( a cry/al make a small angle ) "o ano!r1 z 9 nitre1 ! two sets ( r+s t\* ext]nally2 &1 if ! plate ( nitre be turn$ r\nd 9 its own plane1 ! black transv]se b&s und]go a v>iety ( *anges1 till1 at la/1 ! :ole ri*ly col\r$ image assumes ! =m ( ! figure #h1 trav]s$ by a black cross 7,n4 #bac74 ,sub/ances ) "o optic axis h b "o set ( col\r$ circul> r+s1 ) a broad black cross pass+ ?r\gh its c5tre1 divid+ ! r+s into f\r equal p>ts4 ,:5 ! analyz+ plate revolves1 ?is figure recurs at e qu>t] revolution2 b 9 ! int]m$iate positions x assumes ! complem5t>y col\rs1 ! black cross becom+ :ite4 ,x is 9 va9 to attempt to describe ! beautiful ph5om5a exhibit$ by innum]able bodies :i* und]go p]iodic *anges 9 =m & col\r :5 ! analyz+ plate revolves1 b n "o ( !m %[s a trace ( col\r )\t ! aid ( t\rmal9e1 or some?+ equival5t1 to analyze ! light1 & z x 7 to call ^! beautiful phantoms into exi/5ce4 ,t\rmal9e has ! disadvantage ( be+ itself a col\r$ sub/ance2 b t inconv5i5ce may be obviat$ by employ+ a reflect+ surface z an analyz+ plate4 ,:5 pol>iz$ light is reflect$ by a plate ( glass at ! pol>iz+ angle1 x w be sep>at$ into two col\r$ p5cils2 &1 :5 ! analyz+ plate is turn$ r\nd 9 its own plane1 x w alt]nately reflect ea* ray at e qu>t] revolution1 s t all ! ph5om5a t h be5 describ$ w be se5 by reflection on its surface4 ,col\r$ r+s are produc$ by analyz+ pol>iz$ light transmitt$ ?r\gh glass melt$ & sudd5ly or unequally cool$2 also ?r\gh ?9 plates ( glass b5t ) ! h&1 jelly indurat$ or compress$1 c4 c4 ,9 %ort1 all ! ph5om5a ( col\r$ r+s may be produc$1 ei!r p]man5tly or transi5tly1 9 a v>iety ( sub/ances1 by heat & cold1 rapid cool+1 compression1 dilatation1 & induration2 & s little app>atus is necess>y = p]=m+ ! exp]im5ts1 t1 z ,sir ,john ,h]s*el says1 a piece ( w9d[ glass or a poli%$ table to pol>ize ! light1 a %eet ( cle> ice to produce ! r+s1 & a brok5 fragm5t ( plate-glass plac$ ne> ! eye to analyze ! light1 are alone requisite to produce "o ( ! mo/ spl5did ( optical exhibitions4 ,pressure produces rem>kable *anges 9 ! optical prop]ties ( cry/als4 ,compression1 p]p5dicul> to ! axis1 trans=ms a cry/al ) "o optic axis into "o ) two4 ,a slice ( qu>tz & "o ( b]yl1 bo? cut p]p5dicul>ly to _! axis1 7 compress$ ?us by ,,mm4 ,moignot & ,soleil4 ,!y f\nd t ! s+le sy/em 9 ! qu>tz1 :i* is a positive cry/al1 0 d\bl$ 9 ! direction ( ! compression1 :ile 9 ! b]yl1 :i* is a negative cry/al1 ! duplication 0 p]p5dicul> to ! compression4 ,9 ! qu>tz ! axis ( ! d\ble sy/em co9cid$ ) ! l9e ( pressure1 b 9 ! t\rmal9e1 :i* is a negative cry/al1 ! l9e :i* jo9s ! c5tres ( ! r+s 0 p]p5dicul> to ! pressure4 ,if a positive cry/al be compress$ 9 ! direction ( its axis ! t9t ( ! r+s desc5ds1 & t ( a negative cry/al rises4 ,b if ! cry/als be dilat$ 9 ! direction ( _! optic axis1 ! t9ts 9 positive cry/als rise1 & negative desc5d4 ,x has be5 obs]v$1 t :5 a ray ( light1 pol>iz$ by reflection f any surface n metallic1 is analyz$ by a d\bly refract+ sub/ance1 x exhibits prop]ties :i* are symmetrical bo? to ! "r & left ( ! plane ( reflection1 & ! ray is !n said to be pol>iz$ accord+ to t plane4 ,?is symmetry is n de/roy$ :5 ! ray1 be=e be+ analyz$1 trav]ses ! optic axis ( a cry/al hav+ b "o optic axis1 z evid5tly appe>s f ! circul> =ms ( ! col\r$ r+s already describ$4 ,regul>ly cry/alliz$ qu>tz1 h[ev]1 =ms an exception4 ,9 x1 ev5 ?\gh ! rays %\ld pass ?r\gh ! optic axis itself1 :]e !re is no d\ble refraction1 ! primitive symmetry ( ! ray is de/roy$1 & ! plane ( primitive pol>ization deviates ei!r to ! "r or left ( ! obs]v]1 by an angle proportional to ! ?ickness ( ! plate ( qu>tz4 ,?is angul> motion1 or true rotation ( ! plane ( pol>ization1 :i* is call$ circul> pol>ization1 is cle>ly prov$ by ! ph5om5a4 ,! col\r$ r+s produc$ by all cry/als hav+ b "o optic axis are circul>1 & trav]s$ by a black cross conc5tric ) ! r+s2 s t ! light entirely vani%es ?r\gh\t ! space enclos$ by ! int]ior r+1 because !re is nei!r d\ble refraction nor pol>ization along ! optic axis4 ,b 9 ! sy/em ( r+s produc$ by a plate ( qu>tz1 ^: surfaces are p]p5dicul> to ! axis ( ! cry/al1 ! "p )9 ! int]ior r+1 in/ead ( be+ void ( light1 is occupi$ by a uni=m t9t ( r$1 gre51 or blue1 accord+ to ! ?ickness ( ! plate 7,n4 #bad74 ,suppose ! plate ( qu>tz to be #a_/be ( an in* ?ick1 :i* w give ! r$ t9t to ! space )9 ! int]ior r+2 :5 ! analyz+ plate is turn$1 9 its own plane ?r\gh an angle ( #ag-a_/b1 ! r$ hue vani%es4 ,if a plate ( rock cry/al #b_/be ( an in* ?ick be us$1 ! analyz+ plate mu/ revolve ?r\gh #ce be=e ! r$ t9t vani%es1 & s on1 e additional #be? ( an in* 9 ?ickness requir+ an additional rotation ( #ag-a_/b2 :5ce x is manife/ t ! plane ( pol>ization revolves 9 ! direction ( a spiral )9 ! rock cry/al4 ,x is rem>kable t1 9 "s cry/als ( qu>tz1 ! plane ( pol>ization revolves f "r to left1 & 9 o!rs f left to "r1 al?\gh ! cry/als !mselves diff] app>5tly only by a v slight1 almo/ imp]ceptible1 v>iety 9 =m4 ,9 ^! ph5om5a ! rotation to ! "r is accompli%$ accord+ to ! same laws1 & ) ! same en]gy1 z t to ! left4 ,b if two plates ( qu>tz be int]pos$1 :i* possess diff]5t affections1 ! second plate undoes1 ei!r :olly or p>tly1 ! rotatory motion :i* ! fir/ _h produc$1 accord+ z ! plates are ( equal or unequal ?ickness4 ,:5 ! plates are ( unequal ?ickness1 ! deviation is 9 ! direction ( ! /ronge/1 & exactly ! same ) t :i* a ?ird plate w\ld produce equal 9 ?ickness to ! diff]5ce ( ! two4 ,m4 ,biot has discov]$ ! same prop]ties 9 a v>iety ( liquids4 ,oil ( turp5t9e1 & an ess5tial oil ( laurel1 cause ! plane ( pol>ization to turn to ! left1 :]eas ! syrup ( sug>-cane1 & a solution ( natural camphor1 by alcohol1 turn x to ! "r4 ,a comp5sation is effect$ by ! sup]position or mixture ( two liquids :i* possess ^! opposite prop]ties1 provid$ no *emical action takes place4 ,a rem>kable diff]5ce 0 also obs]v$ by ,m4 ,biot betwe5 ! action ( ! p>ticles ( ! same sub/ances :5 9 a liquid or solid /ate4 ,! syrup ( grapes1 = example1 turns ! plane ( pol>ization to ! left z long z x rema9s liquid2 b1 z soon z x acquires ! solid =m ( sug>1 x causes ! plane ( pol>ization to revolve t[>ds ! "r1 a prop]ty :i* x reta9s ev5 :5 aga9 dissolv$4 ,in/ances occur also 9 :i* ^! circum/ances are rev]s$4 ,a ray ( light pass+ ?r\gh a liquid possess+ ! p[] ( circul> pol>ization is n affect$ by mix+ o!r fluids ) ! liquid--su* z wat]1 e!r1 alcohol1 c4--:i* d n possess circul> pol>ization !mselves1 ! angle ( deviation rema9+ exactly ! same z be=e ! mixture4 ,:5ce ,m4 ,biot inf]s t ! action ex]cis$ by ! liquids 9 "q does n dep5d ^u _! mass1 b t x is a molecul> action ex]cis$ by ! ultimate p>ticles ( matt]1 :i* dep5ds solely ^u ! individual con/itution1 & is entirely indep5d5t ( ! positions & mutual di/ances ( ! p>ticles ) reg>d to ea* o!r4 ,^! important discov]ies %[ t circul> pol>ization surpasses ! p[] ( *emical analysis 9 giv+ c]ta9 & direct evid5ce ( ! simil>ity or diff]5ce exi/+ 9 ! molecul> con/itution ( bodies1 z well z ( ! p]man5cy ( t con/itution1 or ( ! fluctuations to :i* x may be liable4 ,= example1 no *emical diff]5ce has be5 discov]$ betwe5 syrup f ! sug>-cane & syrup f grapes4 ,yet ! fir/ causes ! plane ( pol>ization to revolve to ! "r1 & ! o!r to ! left2 !re=e "s ess5tial diff]5ce mu/ exi/ 9 ! nature ( _! ultimate molecules4 ,! same diff]5ce is to be trac$ betwe5 ! juices ( su* plants z give sug> simil> to t f ! cane1 & ^? :i* give sug> l t obta9$ f grapes4 ,if *lorate ( soda be dissolv$ 9 wat]1 ! liquid has no circul> pol>ization2 b if ! solution be all[$ to cry/allize1 "s ( ! cry/als turn ! light to ! "r & o!rs to ! left4 ,n[1 if all ^? ( "o k9d be ga!r$ toge!r & dissolv$ a second "t1 ! liquid w h no circul> pol>ization2 b if cry/als be all[$ to =m1 "s w turn ! light to ! "r & o!rs to ! left1 al?\gh only "o k9d 0 dissolv$4#aa ,x is a fact e/abli%$ by ,m4 ,biot1 t 9 circul> pol>ization ! laws ( rotation foll[$ by ! diff]5t simple rays ( light are dissimil> 9 diff]5t sub/ances4 ,:5ce he inf]s t ! deviation ( ! simple rays f "o ano!r ought n to result f a special prop]ty ( ! lum9\s pr9ciple only1 b t ! prop] action ( ! molecules mu/ also concur 9 modify+ ! deviations ( ! simple rays diff]5tly 9 diff]5t sub/ances4 ,"o ( ! _m brilliant discov]ies ( ,m4 ,fresnel is ! production ( circul> & elliptical pol>ization by ! int]nal reflection ( light f plate-glass4 ,he has %[n t1 if light pol>iz$ by any ( ! usual me?ods be twice reflect$ )9 a glass rhomb 7,n4 #afi7 ( a giv5 =m1 ! vibrations ( ! e!r t are p]p5dicul> to ! plane ( incid5ce w be ret>d$ a qu>t] ( a vibration1 :i* causes ! vibrat+ p>ticles to describe circles1 & ! succession ( su* vibrat+ p>ticles ?r\gh\t ! ext5t ( a wave to =m altoge!r a circul> helix1 or curve l a corkscrew4 ,h[ev]1 t only happ5s :5 ! plane ( pol>ization is incl9$ at an angle ( #de to ! plane ( incid5ce4 ,:5 ^! two planes =m an angle ei!r great] or less1 ! succession ( vibrat+ p>ticles =ms an elliptical helix1 :i* curve may be repres5t$ by twi/+ a ?read 9 a spiral ab\t an oval rod4 ,^! curves w turn to ! "r or left1 accord+ to ! position ( ! incid5t plane4 ,! motion ( ! e!real m$ium 9 elliptical & circul> pol>ization may be repres5t$ by ! analogy ( a /ret*$ cord2 =1 if ! extremity ( su* a cord be agitat$ at equal & regul> int]vals by a vibratory motion entirely conf9$ to "o plane1 ! cord w be ?r[n into an undulat+ curve ly+ :olly 9 t plane4 ,if to ?is motion !re be sup]add$ ano!r simil> & equal1 b p]p5dicul> to ! fir/1 ! cord w assume ! =m ( an elliptical helix2 its extremity w describe an ellipse1 & e molecule ?r\gh\t its l5g? w successively d ! same4 ,b1 if ! second sy/em ( vibrations comm5ce exactly a qu>t] ( an undulation lat] ?an ! fir/1 ! cord w take ! =m ( a circul> helix or corkscrew1 ! extremity w move uni=mly 9 a circle1 & e molecule ?r\gh\t ! cord w d ! same 9 succession4 ,x appe>s1 !re=e1 t bo? circul> & elliptical pol>ization may be produc$ by ! composition ( ! motions ( two rays 9 :i* ! p>ticles ( e!r vibrate 9 planes at "r angles to "o ano!r4 ,pr(essor ,airy1 9 a v pr(\nd & able pap] publi%$ 9 ! ,cambridge ,transactions1 has prov$ t all ! diff]5t k9ds ( pol>iz$ light are obta9$ f rock cry/al4 ,:5 pol>iz$ light is transmitt$ ?r\gh ! axis ( a cry/al ( qu>tz1 9 ! em]g5t ray ! p>ticles ( e!r move 9 a circul> helix2 & :5 x is transmitt$ obliquely s z to =m an angle ) ! axis ( ! prism1 ! p>ticles ( e!r move 9 an elliptical helix1 ! ellipticity increas+ ) ! obliquity ( ! incid5t ray2 s t1 :5 ! incid5t ray falls p]p5dicul>ly to ! axis1 ! p>ticles ( e!r move 9 a /raight l9e4 ,?us qu>tz exhibits e v>iety ( elliptical pol>ization1 ev5 includ+ ! extreme cases :]e ! exc5tricity is z]o1 or equal to ! great] axis ( ! ellipse 7,n4 #bae74 ,9 _m cry/als ! two rays are s little sep>at$1 t x is only f ! nature ( ! transmitt$ light t !y are kn[n to h ! prop]ty ( d\ble refraction4 ,m4 ,fresnel discov]$1 by exp]im5ts on ! prop]ties ( light pass+ ?r\gh ! axis ( qu>tz1 t x consi/s ( two sup]pos$ rays1 mov+ ) diff]5t velocities2 & ,pr(essor ,airy has %[n t 9 ^! two rays ! molecules ( e!r vibrate 9 simil> ellipses at "r angles to ea* o!r1 b 9 diff]5t directions2 t _! ellipticity v>ies ) ! angle :i* ! incid5t ray makes ) ! axis2 & t1 by ! composition ( _! motions1 !y produce all ! ph5om5a ( pol>iz$ light obs]v$ 9 qu>tz4 ,x appe>s1 f :at has be5 said1 t ! molecules ( e!r always p]=m _! vibrations at "r angles to ! direction ( ! ray1 b v diff]5tly 9 ! v>i\s k9ds ( light4 ,9 natural light ! vibrations are rectil9e>1 & 9 e plane4 ,9 ord9>y pol>iz$ light !y are rectil9e>1 b conf9$ to "o plane2 9 circul> pol>ization ! vibrations are circul>2 & 9 elliptical pol>ization ! molecules vibrate 9 ellipses4 ,^! vibrations are communicat$ f molecule to molecule1 9 /raight l9es :5 !y are rectil9e>1 9 a circul> helix :5 !y are circul>1 & 9 an oval or elliptical helix :5 elliptical4 ,"s fluids possess ! prop]ty ( circul> pol>ization naturally1 z oil ( turp5t9e1 ! ess5tial oils ( laurel & lemon1 sug> ( grapes1 & v>i\s liquids4 ,elliptical pol>ization is produc$ by reflection f metallic surfaces4 ,mr4 ,bad5 ,p[ell discov]$ x also 9 ! light reflect$ f ,*9a ink1 *romate ( lead1 plumbago1 c4 ,mr4 ,airy obs]v$ t ! light reflect$ f ! diamond is elliptically pol>iz$2 & ,mr4 ,jam9 has %[n t ?is k9d ( pol>ization is g5]ally produc$ by reflection f almo/ all transp>5t bodies1 :atev] _! refractive p[] may be1 especially f glass at angles v little diff]5t f ! law ( ! tang5ts4 ,wat] pol>izes light circul>ly :5 betwe5 ! po9ts ( maximum d5sity & solidification2 h5ce x becomes cry/all9e4 ,! col\r$ images f pol>iz$ light arise f ! int]f]5ce ( ! rays 7,n4 #baf74 ,,mm4 ,fresnel & ,arago f\nd t two rays ( pol>iz$ light int]f]e & produce col\r$ fr+es if !y be pol>iz$ 9 ! same plane1 b t !y d n int]f]e :5 pol>iz$ 9 diff]5t planes4 ,9 all int]m$iate positions1 fr+es ( int]m$iate brightness are produc$4 ,! analogy ( a /ret*$ cord w %[ h[ ?is happ5s4 ,suppose ! cord to be mov$ backw>ds & =w>ds horizontally at equal int]vals2 x w be ?r[n into an undulat+ curve ly+ all 9 "o plane4 ,if to ?is motion !re be sup]add$ ano!r simil> & equal1 comm5c+ exactly half an undulation lat] ?an ! fir/1 x is evid5t t ! direct motion e molecule w assume1 9 consequ5ce ( ! fir/ sy/em ( waves1 w at e in/ant be exactly neutraliz$ by ! retrograde motion x w\ld take 9 virtue ( ! second2 & ! cord itself w be quiesc5t 9 consequ5ce ( ! int]f]5ce4 ,b1 if ! second sy/em ( waves be 9 a plane p]p5dicul> to ! fir/1 ! effect w\ld only be to twi/ ! rope1 s t no int]f]5ce w\ld take place4 ,rays pol>iz$ at "r angles to ea* o!r may subsequ5tly be br\ght into ! same plane )\t acquir+ ! prop]ty ( produc+ col\r$ fr+es2 b1 if !y belong to a p5cil ! :ole ( :i* 0 orig9ally pol>iz$ 9 ! same plane1 !y w int]f]e4 ,! mann] 9 :i* ! col\r$ images are =m$ may be conceiv$ by consid]+ t1 :5 pol>iz$ light passes ?r\gh ! optic axis ( a d\bly refract+ sub/ance1--z mica1 = example1--x is divid$ into two p5cils by ! analyz+ t\rmal9e2 &1 z "o ray is absorb$1 !re c be no int]f]5ce4 ,b1 :5 pol>iz$ light passes ?r\gh ! mica 9 any o!r direction1 x is sep>at$ into two :ite rays1 & ^! are aga9 divid$ into f\r p5cils by ! t\rmal9e1 :i* absorbs two ( !m2 & ! o!r two1 be+ transmitt$ 9 ! same plane ) diff]5t velocities1 int]f]e & produce ! col\r$ ph5om5a4 ,if ! analysis be made ) ,icel& sp>1 ! s+le ray pass+ ?r\gh ! optic axis ( ! mica w be refract$ into two rays1 pol>iz$ 9 diff]5t planes1 & no int]f]5ce w happ54 ,b1 :5 two rays are transmitt$ by ! mica1 !y w be sep>at$ into f\r by ! sp>1 two ( :i* w int]f]e to =m "o image1 & ! o!r two1 by _! int]f]5ce1 w produce ! complem5t>y col\rs ( ! o!r image :5 ! sp> has revolv$ ?r\gh #ij2 because1 9 su* positions ( ! sp> z produce ! col\r$ images1 only two rays are visible at a "t1 ! o!r two be+ reflect$4 ,:5 ! analysis is accompli%$ by reflection1 if two rays are transmitt$ by ! mica1 !y are pol>iz$ 9 planes at "r angles to ea* o!r4 ,&1 if ! plane ( reflection ( ei!r ( ^! rays be at "r angles to ! plane ( pol>ization1 only "o ( !m w be reflect$1 & !re=e no int]f]5ce c take place2 b 9 all o!r positions ( ! analyz+ plate bo? rays w be reflect$ 9 ! same plane1 & consequ5tly w produce col\r$ r+s by _! int]f]5ce4 ,x is evid5t t a great deal ( ! light we see mu/ be pol>iz$1 s9ce mo/ bodies :i* h ! p[] ( reflect+ or refract+ light also h ! p[] ( pol>iz+ x4 ,! blue light ( ! sky is completely pol>iz$ at an angle ( #gd f ! sun 9 a plane pass+ ?r\gh 8 c5tre4 ,a con/ellation ( tal5t almo/ unrivall$ at any p]iod 9 ! hi/ory ( sci5ce has contribut$ to ! !ory ( pol>ization1 ?\gh ! orig9al discov]y ( t prop]ty ( light 0 accid5tal1 & arose f an occurr5ce :i*1 l ?\s&s ( o!rs1 w\ld h pass$ unnotic$ _h x n happ5$ to "o ( ^? r>e m9ds capable ( draw+ ! mo/ important inf]5ces f circum/ances app>5tly trifl+4 ,9 #ahjh1 :ile ,m4 ,malus 0 accid5tally view+ ) a d\bly-refract+ prism a brilliant sunset reflect$ f ! w9d[s ( ! ,luxemb\rg ,palace 9 ,p>is1 on turn+ ! prism sl[ly r\nd1 he 0 surpris$ to see a v great diff]5ce 9 ! int5sity ( ! two images1 ! mo/ refract$ alt]nately *ang+ f brightness to obscurity at ea* quadrant ( revolution4 ,a ph5om5on s unlook$ = induc$ him to inve/igate its cause1 :5ce sprung "o ( ! mo/ elegant & ref9$ bran*es ( physical optics4 ,fluoresc5ce1 or ! int]nal disp]sion ( light1 ?\gh f> f possess+ ! beauty or ext5sive consequ5ces ( pol>iz$ light1 is sc>cely less wond]ful4 ,a v>iety ( sub/ances1 su* z can>y-glass1 a solution ( sulphate ( qu99e1 fluor-sp>1 & a great numb] ( organic sub/ances1 h ! prop]ty ( dim9i%+ ! refrangibility ( light by int]nal disp]sion1 consequ5tly ( increas+ ! l5g? ( ! waves1 & l[]+ ! col\r 9 ! prismatic scale2 x is !re=e call$ degrad$ light1 or fluoresc5ce1 because fir/ discov]$ 9 fluor-sp>4 ,if a piece ( glass col\r$ by cobalt be fix$ 9 a hole 9 a w9d[-%utt] ( a d>k room1 a slab ( :ite porcela9 plac$ ne> x w appe> blue2 b if ! slab be view$ ?r\gh a yell[ glass col\r$ by silv]1 x w appe> to be almo/ q black1 because ! yell[ glass absorbs all ! rays transmitt$ by ! blue glass4 ,if1 h[ev]1 a piece ( can>y-glass be laid on ! slab :ile x is d>k1 e "p ( ! can>y-glass w %9e z if x 7 self-lum9\s1 & ) s bright a light t any?+ writt5 on ! slab t 0 invisible be=e may n[ be di/9ctly read4 ,su* is ! s+ul> ph5om5on ( int]nal disp]sion1 degrad$ light1 or fluoresc5ce4 ,! brightness is by no means due to phosphoresc5ce1 because ! can>y-glass only %9es :5 "u ! influ5ce ( ! active or blue rays1 :]eas phosphoresc5t bodies %9e by _! own light--! latt] has indep5d5t1 ! =m] dep5d5t1 emission2 x is possible1 h[ev]1 t a connexion may h]eaft] be trac$ betwe5 !m4 ,x appe>s f ! analytical inve/igation ( ?is ph5om5on t ! vibrations ( ! fluoresc5t sub/ance are analog\s to ^? ( a sonor\s body1 z a bell or musical cord1 :i* give ! fundam5tal note & its h>monics4 ,n[ s9ce !re is a reciprocal action betwe5 ! molecules ( matt] & light1 :5 ! light ( ! sun is absorb$ by a sub/ance capable ( fluoresc5ce1 x puts ! :ole ( its molecules into vibrations ! same z its own1 analog\s to ! fundam5tal note1 :ile at ! same "t a c]ta9 numb] ( molecules take m rapid vibrations exactly l ! h>monics4 ,! latt] =m new c5tres ( light ?r\gh\t ! sub/ance1 :i* imp>t _! vibrations to ! e!real m$ium ar\nd1 & con/itute fluoresc5ce or degrad$ light4 ,= example1 9 ! exp]im5t t has be5 describ$1 ! blue light imp>t$ its own vibrations to all ! molecules ( ! can>y-glass1 & also m rapid vibrations to a c]ta9 numb] ( !m4 ,all ( ! blue rays 7 exclud$ by ! yell[ glass held be=e ! eye2 b x 0 p]vi\s to ! rays emanat+ 9 m rapid vibrations f ! small] numb] ( molecules1 :i* ?us became really new c5tres ( light1 diff]5t f ! sun's light1 ?\gh ow+ to x2 ! "o cele/ial1 ! o!r t]re/rial2 & ! latt] vibrations be+ m rapid ?an ^? ( ! blue light1 _! refrangibility 0 less1 & !re=e _! col\r l[] 9 ! prismatic scale4 ,mr4 ,p[] comput$ f 8 =mul1 t fluoresc5t light is produc$ by undulations :i* are a major or m9or ?ird bel[ ! pit* ( ! g5]al vibration ( ! m$ium--t is to say1 bel[ ! vibrations :i* ! :ole molecules ( ! body mo/ readily assume4 ,pr(essor ,/okes1 ( ,cambridge1 :o made ! prec$+ exp]im5t1 f\nd t ! *emical rays f a po9t 9 ! sol> spectrum produc$1 9 a solution ( ! sulphate ( qu99e1 light ( a sky-blue col\r1 :i* emanates 9 all directions f ! liquid1 & t ?is blue fluoresc5t light conta9s1 :5 analys$1 all ! rays ( ! spectrum2 h5ce he inf]r$ t ! disp]sive p[] or fluoresc5ce _h l[]$ ! refrangibility ( ! *emical rays1 s z to make !m visible3 & ,sir ,david ,brew/] obs]ves t ! new spectrum1 ( all col\rs into :i* !y 7 trans=m$1 mu/ possess ! extraord9>y prop]ty ( be+ a lum9\s spectrum1 ei!r )\t *emical rays or full ( !m4 ,! disp]sion 9 ! qu99e solution is greate/ ne> ! surface1 b ! blue emanation proce$s f e "p ( ! liquid2 & ,sir ,john ,h]s*el1 :o discov]$ ! fluoresc5t prop]ty 9 ?is liquid1 & gave x ! "n ( epipolic light1 f\nd t ! rema9d] ( ! beam1 :5 x issu$ f ! solution1 ?\gh n app>5tly diff]5t f ! incid5t :ite light1 is yet s mu* *ang$ 9 pass+ ?r\gh ! liquid1 t x is no long] capable ( produc+ fluoresc5ce1 ?\gh /ill capable ( common disp]sion4 ,! blue light f ! solution ( qu99e1 :5 exam9$1 consi/$ ( rays ext5d+ ov] a great "p ( ! spectrum4 ,by pass+ a sunbeam ?r\gh a blui% k9d ( fluor-sp>1 ,sir ,david ,brew/] p]ceiv$ t ! blue col\r is n sup]ficial1 z x appe>s to be1 b t "s ve9s 9 ! int]ior ( ! cry/al disp]se blue light1 o!rs p9k1 & ev5 :ite light2 9 %ort1 he met ) fluoresc5ce 9 su* a v>iety ( sub/ances1 t he concludes x may prevail m or less 9 ! great] numb] ( solids & liquids4 ,pr(essor ,drap]1 ( ,new ,york1 prov$ t ! result is ! same :e!r ! incid5t light be pol>iz$ or n1 & t ! disp]s$ or degrad$ light is nev] pol>iz$1 b t x emanates 9 all directions1 z if ! sub/ance 7 self-lum9\s2 he made exp]im5ts ) light f all p>ts ( ! sol> spectrum1 & ) v>i\s sub/ances1 & always f\nd t ! refrangibility ( ! incid5t ray 0 dim9i%$ by int]nal disp]sion1 & t ! col\r 0 *ang$ to suit ! new refrangibility4 ,pr(essor ,drap] has also %[n t ! law ( action & reaction prevails 9 all ! ph5om5a ( ! sunbeam1 z 9 e o!r dep>tm5t ( nature2 s t a beam _c be reflect$1 refract$1 mu* less absorb$1 )\t produc+ "s *ange ^u ! recipi5t m$ium2 & ,mr4 ,p[] prov$ analytically t ! sol> rays c ex]cise no action ^u any m$ium ?r\gh :i* !y are transmitt$1 )\t be+ accompani$ by a dim9ution ( refraction4 ,he says1 8,! new light emanat+ f ! fluoresc5t m$ia is j l any o!r light ( ! same prismatic composition4 ,9 its physical prop]ties x reta9s no trace ( its p>5tage2 x is ( t]re/rial orig91 & its col\r dep5ds simply on its new refrangibility1 hav+ no?+ to d ) t ( ! produc+ rays1 nor to ! circum/ance ( _! belong+ to ! visible or invisible "p ( ! spectrum40 ,^! ph5om5a c only be expla9$ by ! undulatory !ory ( light4 ,,section ,,xxiii4 ,objections to ! ,undulatory ,!ory1 f a diff]5ce 9 ! ,action ( ,s\nd & ,light "u ! same circum/ances1 remov$--,! ,disp]sion ( ,light accord+ to ! ,undulatory ,!ory--,arago's f9al pro( t ! ,undulatory ,!ory is ! ,law ( ,nature4 ,,! num]\s ph5om5a ( p]iodical col\rs aris+ f ! int]f]5ce ( light1 :i* d n admit ( satisfactory explanation on any o!r pr9ciple ?an ! undulatory !ory1 are ! /ronge/ argum5ts 9 fav\r ( t hypo!sis2 & ev5 cases :i* at "o "t seem$ unfav\rable to t doctr9e h prov$ ^u inve/igation to proce$ f x alone4 ,su* is ! errone\s objection :i* has be5 made1 9 consequ5ce ( a diff]5ce 9 ! mode ( action ( light & s\nd1 "u ! same circum/ances1 9 "o p>ticul> in/ance4 ,:5 a ray ( light f a lum9\s po9t1 & a div]g+ s\nd1 are bo? transmitt$ ?r\gh a v small hole into a d>k room1 ! light goes /raight =w>d & illum9ates a small spot on ! opposite wall1 leav+ ! re/ 9 d>kness2 :]eas ! s\nd on ent]+ div]ges 9 all directions1 & is he>d 9 e "p ( ! room4 ,^! ph5om5a1 h[ev]1 in/ead ( be+ at v>iance ) ! undulatory !ory1 are direct consequ5ces ( x1 aris+ f ! v great diff]5ce betwe5 ! magnitude ( ! undulations ( s\nd & ^? ( light4 ,! undulations ( light are incomp>ably less ?an ! m9ute ap]ture1 :ile ^? ( s\nd are mu* great]4 ,!re=e :5 light1 div]g+ f a lum9\s po9t1 ent]s ! hole1 ! rays r\nd its edges are oblique1 & consequ5tly ( diff]5t l5g?s1 :ile ^? 9 ! c5tre are direct1 & ne>ly or altoge!r ( ! same l5g?s4 ,s t ! small undulations betwe5 ! c5tre & ! edges are 9 diff]5t phases1 t is1 9 diff]5t /ates ( undulation4 ,!re=e ! great] numb] ( !m int]f]e1 & by de/roy+ "o ano!r produce d>kness all ar\nd ! edges ( ! ap]ture2 :]eas ! c5tral rays1 hav+ ! same phases1 comb9e1 & produce a spot ( bright light on a wall or scre5 directly opposite ! hole4 ,! waves ( air produc+ s\nd1 on ! contr>y1 be+ v l>ge comp>$ ) ! hole1 d n s5sibly div]ge 9 pass+ ?r\gh x1 & are !re=e all s ne>ly ( ! same l5g?1 & consequ5tly 9 ! same phase or /ate ( undulation1 t none ( !m int]f]e suffici5tly to de/roy "o ano!r4 ,h5ce all ! p>ticles ( air 9 ! room are set into a /ate ( vibration1 s t ! int5sity ( ! s\nd is v ne>ly ev]y:]e ! same4 ,/rong z ! prec$+ cases may be1 ! foll[+ exp]im5t1 made by ,m4 ,arago1 seems to be decisive 9 fav\r ( ! undulatory doctr9e4 ,suppose a plano-convex l5s ( v great radius to be plac$ ^u a plate ( v highly poli%$ metal4 ,:5 a ray ( pol>iz$ light falls ^u ?is app>atus at a v great angle ( incid5ce1 ,newton's r+s are se5 at ! po9t ( contact4 ,b z ! pol>iz+ angle ( glass diff]s f t ( metal1 :5 ! light falls on ! l5s at ! pol>iz+ angle ( glass1 ! black spot & ! sy/em ( r+s vani%4 ,= al?\gh light 9 abundance cont9ues to be reflect$ f ! surface ( ! metal1 n a ray is reflect$ f ! surface ( ! glass t is 9 contact ) x1 consequ5tly no int]f]5ce c take place2 :i* proves beyond a d\bt t ,newton's r+s result f ! int]f]5ce ( ! light reflect$ f bo? ! surfaces app>5tly 9 contact 7,n4 #aii74 ,not)/&+ ! successful adaptation ( ! undulatory sy/em to ph5om5a1 ! disp]sion ( light = a long "t (f]$ a =midable objection to t !ory1 :i* has be5 remov$ by ,pr(essor ,p[ell ( ,ox=d4 ,a sunbeam fall+ on a prism1 in/ead ( be+ refract$ to a s+le po9t ( :ite light1 is sep>at$ into its compon5t col\rs1 :i* are disp]s$ or scatt]$ unequally ov] a consid]able space1 ( :i* ! portion occupi$ by ! r$ rays is ! lea/1 & t ov] :i* ! violet rays are disp]s$ is ! greate/4 ,?us ! rays ( ! col\r$ spectrum1 ^: waves are ( diff]5t l5g?s1 h diff]5t degrees ( refrangibility1 & consequ5tly move ) diff]5t velocities1 ei!r 9 ! m$ium :i* conveys ! light f ! sun1 or 9 ! refract+ m$ium1 or 9 bo?2 :]eas rays ( all col\rs come f ! sun to ! e>? ) ! same velocity4 ,if1 inde$1 ! velocities ( ! v>i\s rays 7 diff]5t 9 space1 ! ab]ration ( ! fix$ />s1 :i* is inv]sely z ! velocity1 w\ld be diff]5t = diff]5t col\rs1 & e /> w\ld appe> z a spectrum ^: l5g? w\ld be p>allel to ! direction ( ! e>?'s motion1 :i* is n f\nd to agree ) obs]vation4 ,besides1 !re is no su* diff]5ce 9 ! velocities ( ! long & %ort waves ( air 9 ! analog\s case ( s\nd1 s9ce notes ( ! l[e/ & highe/ pit* are he>d 9 ! ord] 9 :i* !y are /ruck4 ,9 fact1 :5 ! sunbeam passes f air into ! prism1 its velocity is dim9i%$2 &1 z its refraction1 & consequ5tly its disp]sion1 dep5d solely ^u ! dim9i%$ velocity ( ! transmission ( its waves1 !y ought to be ! same = waves ( all l5g?s1 unless a connexion exi/s betwe5 ! l5g? ( a wave & ! velocity ) :i* x is propagat$4 ,n[1 ?is connexion betwe5 ! l5g? ( a wave ( any col\r1 & its velocity or refrangibility 9 a giv5 m$ium1 has be5 d$uc$ by ,pr(essor ,p[ell f ,m4 ,cau*y's inve/igations ( ! prop]ties ( light on a peculi> modification ( ! undulatory hypo!sis4 ,h5ce ! refrangibility ( ! v>i\s col\r$ rays1 comput$ f ?is relation = any giv5 m$ium1 :5 comp>$ ) _! refrangibility 9 ! same m$ium det]m9$ by actual obs]vation1 w %[ :e!r ! disp]sion ( light comes "u ! laws ( t !ory4 ,b1 9 ord] to accompli% ?is1 x is cle> t ! l5g? ( ! waves %\ld be f\nd indep5d5tly ( refraction1 & a v beautiful discov]y ( ,m4 ,fraunh(] furni%es ! means ( do+ s4 ,t philosoph] obta9$ a p]fectly pure & complete col\r$ spectrum1 ) all its d>k & bright l9es1 by ! int]f]5ce ( light alone1 f a sunbeam pass+ ?r\gh a s]ies ( f9e p>allel wires cov]+ ! object glass ( a telescope4 ,9 ?is spectrum1 =m$ indep5d5tly ( prismatic refraction1 ! positions ( ! col\r$ rays dep5d only on ! l5g?s ( _! waves1 & ,m4 ,fraunh(] f\nd t ! int]vals betwe5 !m are precisely proportional to ! diff]5ces ( ^! l5g?s4 ,he measur$ ! l5g?s ( ! waves ( ! diff]5t col\rs at sev5 fix$ po9ts1 det]m9$ by sev5 ( ! pr9cipal d>k & bright l9es4 ,pr(essor ,p[ell1 avail+ himself ( ^! measures1 has made ! requisite computations1 & has f\nd t ! co9cid5ce ( !ory ) obs]vation is p]fect = t5 sub/ances ^: refrangibility _h be5 previ\sly det]m9$ by ! direct measurem5ts ( ,m4 ,fraunh(]1 & = t5 o!rs ^: refrangibility has m rec5tly be5 asc]ta9$ by ,m4 ,rudb]g4 ,?us1 9 ! case ( sev5 rays 9 ea* ( tw5ty diff]5t sub/ances1 solid & fluid1 ! disp]sion ( light takes place accord+ to ! laws ( ! undulatory !ory3 & !re c h>dly be a d\bt t disp]sion 9 all o!r bodies w be f\nd to foll[ ! same law4 ,x is1 h[ev]1 an express condition ( ! connexion betwe5 ! velocity ( light & ! l5g? ( its undulations1 t ! int]vals betwe5 ! vibrat+ molecules ( ! e!real fluid %\ld be> a s5sible relation to ! l5g? ( an undulation4 ,! co9cid5ce ( ! comput$ ) ! obs]v$ refractions %[s t ?is condition is fulfill$ )9 ! refract+ m$ia2 b ! ab]ration ( ! fix$ />s leads to ! inf]5ce t x does n hold 9 ! e!real regions1 :]e ! velocities ( ! rays ( all col\rs are ! same4 ,/rong z all t prec$es is 9 fav\r ( ! undulatory !ory1 ! relative velocity ( light 9 air & wat] is ! f9al & decisive pro(4 ,by ! ,newtonian !ory ! velocity is great] 9 wat] ?an 9 air1 by ! undulatory !ory x is less2 h5ce if a comp>ison c\ld be made x w\ld decide :i* is ! law ( nature4 ,! difficulty consi/$ 9 comp>+ ! velocity ( light pass+ ?r\gh a small ext5t ( wat] ) ! velocity ( light 9 air1 :i* is #aj1jjj times great] ?an ! velocity ( ! e>? 9 its orbit4 ,?is delicate & difficult exp]im5t 0 made by means ( an in/rum5t inv5t$ by ,pr(essor ,:eat/one = measur+ ! velocity ( electricity4 ,x consi/s ( a small mirror :i* revolves 9 its own plane l a co9 sp9n+ on its edge4 ,:5 x revolves v rapidly ! reflect$ image ( an object *anges its place p]ceptibly 9 an inconceivably small fraction ( a second4 ,! mirrors us$ 9 ! exp]im5t 7 made to revolve m ?an #ajjj times 9 a second1 by :i* means ! places ( ! two images--"o f light pass+ ?r\gh air1 & ! o!r f light pass+ ?r\gh an equal l5g? ( wat]--7 f\nd to be su* z to prove t ! velocity ( light 9 air & 9 wat] is z #d to #c1 :ile by ! ,newtonian !ory x is z #c to #d4 ,by ?is f9al & decisive pro( ! undulatory !ory may f h5ce=? be reg>d$ z ! law ( nature4 ,?is exp]im5t 0 accompli%$ by ,m4 ,fizeau & ,m4 ,lon-,faucault1 at ! sugge/ion ( ,m4 ,arago1 ^: eyesight did n p]mit him to und]take x himself4 ,,section ,,xxiv4 ,*emical or ,photographic ,rays ( ,sol> ,spectrum--,s*eele1 ,ritt]1 & ,wolla/on's ,discov]ies--,w$gwood's & ,sir ,humphry ,davy's ,photographic ,pictures--,! ,calotype--,! ,dagu]reotype--,! ,*romatype--,! ,cyanotype--,collodion--,sir ,john ,h]s*el's ,discov]ies 9 ! ,*emical ,spectrum--,m4 ,becqu]el's ,discov]ies ( ,inactive ,l9es 9 ditto--,!rmic ,spectrum--,phosphoric ,spectrum--,electrical ,prop]ties--,p>a!rmic ,rays--,mos] & ,hunt's ,exp]im5ts--,g5]al ,/ructure & antagoni/ ,prop]ties ( ,sol> ,spectrum--,defract$ ,spectrum4 ,,! ,sol> ,spectrum ex]cises an en]getic action on matt]1 produc+ ! mo/ wond]ful & my/]i\s *anges on ! organis$ & unorganis$ creation4 ,all bodies are probably affect$ by light1 b x acts ) greate/ en]gy on su* z are ( weak *emical aff9ity1 imp>t+ prop]ties to !m :i* !y did n possess be=e4 ,collodion & metallic salts1 especially ^? ( silv]1 ^: molecules are held toge!r by an un/able equilibrium1 are ( all bodies ! mo/ susceptible ( its influ5ce2 ! effects1 h[ev]1 v>y ) ! sub/ances employ$1 & ) ! diff]5t rays ( ! sol> spectrum1 ! *emical prop]ties ( :i* are by no means alike4 ,z e>ly z #aggb ,m4 ,s*eele %[$ t ! pure :ite col\r ( *loride ( silv] 0 rapidly d>k5$ by ! blue rays ( ! sol> spectrum1 :ile ! r$ rays _h no effect ^u x3 & 9 #ahja ,m4 ,ritt] discov]$ t invisible rays beyond ! violet extremity h ! prop]ty ( black5+ arg5t9e salts1 t ?is prop]ty dim9i%es t[>ds ! less refrangible "p ( ! spectrum1 & t ! r$ rays h an opposite quality1 t ( re/or+ ! black5$ salt ( silv] to its orig9al purity2 f :i* he inf]r$ t ! mo/ refrangible extremity ( ! spectrum has an oxyg5is+ p[]1 & ! o!r t ( deoxyg5at+4 ,dr4 ,wolla/on f\nd t gum guaiacum acquires a gre5 col\r 9 ! violet & blue rays1 & resumes its orig9al t9t 9 ! r$4 ,no attempt _h be5 made to trace natural objects by means ( light reflect$ f !m1 till ,mr4 ,w$gwood1 toge!r ) ,sir ,humphry ,davy1 took up ! subject3 !y produc$ pr(iles & trac+s ( objects on surfaces prep>$ ) nitrate & *loride ( silv]1 b !y did n succe$ 9 r5d]+ _! pictures p]man5t4 ,?is difficulty 0 ov]come 9 #ahad by ,m4 ,niepc1 :o produc$ a p]man5t picture ( surr\nd+ objects by plac+ 9 ! focus ( a cam]a-obscura a metallic plate cov]$ ) a film ( asphalt dissolv$ 9 oil ( lav5d]4 ,mr4 ,fox ,talbot1 )\t any k ( ,m4 ,niepc's exp]im5ts1 _h be5 engag$ 9 ! same pursuit1 & mu/ be reg>d$ z an indep5d5t inv5tor ( photography1 "o ( ! mo/ beautiful arts ( mod]n times3 he 0 ! fir/ :o succe$$ 9 us+ pap] *emically prep>$ = receiv+ impressions f natural objects2 & he also discov]$ a me?od ( fix+ p]man5tly ! impressions--t is1 ( r5d]+ ! pap] ins5sible to any fur!r action ( light4 ,9 ! calotype1 "o ( ,mr4 ,talbot's applications ( ! art1 ! photographic surface is prep>$ by wa%+ smoo? writ+-pap]1 fir/ ) a solution ( nitrate ( silv]1 !n ) bromide ( potassium1 & aga9 ) nitrate ( silv]1 dry+ x at a fire aft] ea* wa%+2 ! pap] is ?us r5d]$ s s5sitive to light t ev5 ! passage ( a ?9 cl\d is p]ceptible on x1 consequ5tly x mu/ be prep>$ by c&le-light4 ,portraits1 build+s1 insects1 leaves ( plants--9 %ort1 e object is accurately del9eat$ 9 a few seconds2 & 9 ! focus ( a cam]a-obscura ! mo/ m9ute objects are s exactly depict$ t ! microscope reveals new beauties4 ,s9ce ! effect ( ! *emical ag5cy ( light is to de/roy ! aff9ity betwe5 ! salt & ! silv]1 ,mr4 ,talbot f\nd t1 9 ord] to r5d] ^! impressions p]man5t on pap]1 x 0 only necess>y to wa% x ) salt & wat]1 or ) a solution ( iodide ( potassium4 ,= ^! liquids ! liquid hyposulphites h be5 advantage\sly sub/itut$1 :i* are ! mo/ efficaci\s 9 dissolv+ & remov+ ! un*ang$ salt1 leav+ ! r$uc$ silv] on ! pap]4 ,! calotype picture is negative1 t is1 ! lights & %ad[s are ! rev]se ( :at !y are 9 nature1 & ! "r-h& side 9 nature is ! left 9 ! picture2 b if x be plac$ ) its face press$ aga9/ photographic pap]1 betwe5 a bo>d & a plate ( glass1 & expos$ to ! sun a %ort "t1 a positive & direct picture1 z x is 9 nature1 is =m$3 engrav+s may be exactly copi$ by ?is simple process1 & a direct picture may be produc$ at once by us+ photographic pap] already made br[n by exposure to light4 ,:ile ,mr4 ,fox ,talbot 0 engag$ 9 ^! v elegant discov]ies 9 ,engl&1 ,m4 ,dagu]re _h br\ght to p]fection & made public t admirable process by :i* he has compell$ ,nature p]man5tly to engrave h] own works2 & ?us ! tal5ts ( ,france & ,engl& h be5 comb9$ 9 br++ to p]fection ?is useful art4 ,copp]1 plat$ ) silv]1 0 successfully employ$ by ,m4 ,dagu]re = copy+ nature by ! ag5cy ( light4 ,! surface ( ! plate is conv]t$ into an iodide ( silv]1 by plac+ x horizontally ) its face d[nw>ds 9 a cov]$ box1 9 ! bottom ( :i* !re is a small quantity ( iod9e :i* evaporates spontane\sly4 ,9 ?ree or f\r m9utes ! surface acquires a yell[ t9t1 & !n1 scre5+ x c>efully f light1 x mu/ be plac$ 9 ! focus ( a cam]a obscura1 :]e an invisible image ( ext]nal objects w be impress$ on x 9 a few m9utes4 ,:5 tak5 out1 ! plate mu/ be expos$ 9 ano!r box to ! action ( m]curial vap\r1 :i* atta*es itself to ^? p>ts ( ! plate :i* _h be5 expos$ to light1 b does n adh]e to su* p>ts z _h be5 9 %ad[2 & z ! quantity ( m]cury ov] ! o!r p>ts is 9 exact proportion to ! degree ( illum9ation1 ! %ad+ ( ! picture is p]fect4 ,! image is fix$1 fir/ by remov+ ! iod9e f ! plate by plung+ x into hyposulphite ( soda1 & !n wa%+ x 9 di/ill$ wat]2 by ?is process ! yell[ col\r is de/roy$1 & 9 ord] to r5d] ! m]cury p]man5t1 ! plate mu/ be expos$ a few m9utes to nitric vap\r1 !n plac$ 9 nitric acid conta9+ copp] or silv] 9 solution at a temp]ature ( #fa-a_/d ( ,fahr5heit = a %ort "t1 & la/ly poli%$ ) *alk4 ,?is f9al "p ( ! process is due to ,dr4 ,b]re1 ( ,vi5na4 ,no?+ c be m beautiful ?an ! %ad+ ( ^! *i>oscuro pictures :5 objects are at re/1 b ! lea/ motion de/roys ! effect2 ! me?od !re=e is m applicable to build+s ?an l&scape4 ,col\r is want+2 b ! rese>*es ( ,sir ,john ,h]s*el give reason to believe t ev5 ?is w ultimately be atta9$4 ,! mo/ p]fect impressions ( seawe$s1 leaves ( plants1 fea!rs1 c41 may be =m$ by br++ ! object into close contact ) a %eet ( photographic pap]1 betwe5 a bo>d & plate ( glass2 !n expos+ ! :ole to ! sun = a %ort "t1 & aft]w>ds fix+ x by ! process describ$4 ,! col\rs ( ! pictures v>y ) ! prep>ation ( ! pap]1 by :i* almo/ any t9t may be produc$4 ,9 ! *romatype1 a peculi> photograph discov]$ by ,mr4 ,hunt1 *romate ( copp] is us$1 on :i* a d>k br[n negative image is fir/ =m$1 b by ! cont9u$ action ( light x is *ang$ to a positive yell[ picture on a :ite gr\nd2 ! f>!r effect ( light is *eck$ by wa%+ ! picture 9 pure wat]4 ,9 cyanotypes1 a class ( photographs discov]$ by ,sir ,john ,h]s*el1 9 :i* cyanog5 9 its comb9ations ) iron =ms ! gr\nd1 ! pictures are ,prussian blue & :ite4 ,9 ! *rysotype ( ! same em95t philosoph]1 ! image is fir/ receiv$ on pap] prep>$ ) ! ammonia-citrate ( iron1 & aft]w>ds wa%$ ) a neutral solution ( gold4 ,x is fix$ by wat] acidulat$ ) sulphuric acid1 & la/ly by hydriodate ( pota%1 f :i* a :ite & purple photograph results4 ,x is va9 to attempt to describe ! v>i\s beautiful effects :i* ,sir ,john ,h]s*el obta9$ f *emical comp\nds1 & f ! juices ( plants2 ! juice ( ! r$ poppy gives a positive blui% purple image1 t ( ! t5-week /ock a f9e rose col\r on a pale /raw-col\r$ gr\nd4 ,pictures may be made by exposure to sun%9e1 on all comp\nd sub/ances hav+ a weak *emical aff9ity2 b ! image is (t5 invisible1 z 9 ! ,dagu]reotype1 till br\ght out by wa%+ 9 "s *emical prep>ation4 ,wat] is frequ5tly suffici5t2 inde$ ,sir ,john ,h]s*el br\ght out dormant photographs by brea?+ on !m1 & "s sub/ances are ins5sible to ! action ( light till moi/5$1 z = example1 gum guaiacum4 ,arg5t9e pap]s1 h[ev]1 are little subject to ! influ5ce ( moi/ure4 ,! p[] ( ! sol> rays is augm5t$ 9 c]ta9 cases by plac+ a plate ( glass 9 close contact ov] ! s5sitive surface4 ,all ^! v>i\s exp]im5ts1 ?\gh highly int]e/+1 h n[ be5 sup]s$$4 ,x 0 f\nd t pap] did n always answ] = photography1 on acc\nt ( imp]fections 9 its /ructure2 silv] plates 7 too exp5sive2 & glass 0 f\nd to be unimpressable4 ,nev]!less1 ,m4 ,niepc de ,victor obta9$ beautiful results ^u glass coat$ ) album5 mix$ ) s5sitive sub/ances1 :i* sugge/$ ! m$ium by means ( :i* ! art has be5 br\ght to its pres5t p]fection1 & t f9al /ep is due to ,mr4 ,scott ,ar*]4 ,he coat$ a plate ( glass ?9ly ) collodion1 t is1 gun-cotton dissolv$ 9 e!r & alcohol1 :i* dries into a delicate transp>5t film ( extreme adhesiv5ess1 & ( su* int5se s5sibility t ! action ( light ^u x is s in/antane\s t x arre/s a /ormy sea or a fleet+ cl\d be=e !y h "t to *ange4 ,n[ l&scapes 9 *i>oscuro are produc$ ( great beauty1 :i* by ! sl[] me?ods 7 m]e masses ( deep %ade & broad light4 ,ar*itecture is ev5 m p]fectly obta9$1 b x fails to give a pleas+ repres5tation ( ! human c\nt5ance4 ,*emical action always accompanies ! sun's light1 b ! analysis ( ! sol> spectrum has p>tly disclos$ ! wond]ful nature ( ! emanation4 ,9 ! rese>*1 prop]ties mo/ important & unexpect$ h be5 discov]$ by ,sir ,john ,h]s*el1 :o impr9ts ! /amp ( g5ius on all he t\*es--8 eloqu5t pap]s c alone convey an adequate idea ( _! value 9 op5+ a field ( inquiry va/ & untrodd54 ,! foll[+ brief & imp]fect acc\nt ( 8 exp]im5ts is all t c be attempt$ "h3-- ,a c]ta9 degree ( *emical en]gy is di/ribut$ ?r\gh e "p ( ! sol> spectrum1 & also to a consid]able ext5t ?r\gh ! d>k spaces at ea* extremity4 ,?is di/ribution does n dep5d on ! refrangibility ( ! rays alone1 b also on ! nature ( ! rays !mselves1 & on ! physical prop]ties ( ! analyz+ m$ium on :i* ! rays are receiv$1 ^: *anges indicate & measure _! action4 ,! l5g? ( ! photographic image ( ! same sol> spectrum v>ies ) ! physical qualities ( ! surface on :i* x is impress$4 ,:5 ! sol> spectrum is receiv$ on pap] prep>$ ) bromide ( silv]1 ! *emical spectrum1 z indicat$ m]ely by ! l5g? ( ! d>k5$ "p1 includes )9 its limits ! :ole lum9\s spectrum1 ext5d+ 9 "o direction f> beyond ! extreme violet & lav5d] rays1 & 9 ! o!r d[n to ! extreme/ r$3 ) t>trate ( silv] ! d>k5+ occupies n only all ! space "u ! mo/ refrangible rays1 b rea*es mu* beyond ! extreme r$4 ,on pap] prep>$ ) =mob5zoate ( silv] ! *emical spectrum is cut (f at ! orange rays1 ) phosphate ( silv] 9 ! yell[1 & ) *loride ( gold x t]m9ates ) ! gre51 ) c>bonate ( m]cury x ends 9 ! blue1 & on pap] prep>$ ) ! p]cyanide ( gold1 ammonia1 & nitrate ( silv]1 ! d>k5+ lies entirely beyond ! visible spectrum at its mo/ refrangible extremity1 & is only half its l5g?1 :]eas 9 "s cases *emical action occupies a space m ?an twice ! l5g? ( ! lum9\s image4 ,! po9t ( maximum en]gy ( *emical action v>ies z mu* = diff]5t prep>ations z ! scale ( action4 ,9 ! great] numb] ( cases ! po9t ( deepe/ black5+ lies ab\t ! l[] edge ( ! indigo rays1 ?\gh 9 no two cases is x exactly ! same1 & 9 _m sub/ances x is widely diff]5t4 ,on pap] prep>$ ) ! juice ( ! t5-week /ock 7,ma?iola annua7 !re are two maxima1 "o 9 ! mean yell[ & a weak] 9 ! violet2 & on a prep>ation ( t>trate ( silv] ,sir ,john ,h]s*el f\nd ?ree1 "o 9 ! lea/ refrangible blue1 "o 9 ! indigo1 & a ?ird beyond ! visible violet4 ,! decrease 9 photographic en]gy is seldom p]fectly alike on bo? sides ( ! maximum4 ,?us at ! mo/ refrangible end ( ! sol> spectrum ! greate/ *emical p[] is ex]t$ 9 mo/ in/ances :]e !re is lea/ light & heat1 & ev5 9 ! space :]e bo? s5sibly cease4 ,n only ! int5sity b ! k9d ( action is diff]5t 9 ! diff]5t po9ts ( ! sol> spectrum1 z evid5tly appe>s f ! v>i\s col\rs t are frequ5tly impress$ on ! same analyz+ surface1 ea* ray hav+ a t5d5cy to imp>t its own col\r4 ,sir ,john ,h]s*el obta9$ a col\r$ image ( ! sol> spectrum on pap] prep>$ accord+ to ,mr4 ,talbot's pr9ciple1 f a sunbeam refract$ by a glass prism & !n highly cond5s$ by a l5s4 ,! photographic image 0 rapidly =m$ & v int5se1 &1 :5 )drawn f ! spectrum & view$ 9 common daylight1 x 0 f\nd to be col\r$ ) sombre b unequivocal t9ts imitat+ ! prismatic col\rs1 :i* v>i$ gradually f r$ ?r\gh gre5 & blue to a purpli% black4 ,aft] wa%+ ! surface 9 wat]1 ! t9ts became m decid$ by be+ kept a few days 9 ! d>k--a ph5om5on1 ,sir ,john obs]ves1 ( con/ant occurr5ce1 :atev] be ! prep>ation ( ! pap]1 provid$ col\rs are produc$ at all4 ,he also obta9$ a col\r$ image on nitrate ( silv]1 ! "p "u ! blue rays becom+ a blue br[n1 :ile t "u ! violet _h a p9ki% %ade1 & sometimes gre5 appe>$ at ! po9t correspond+ to ! lea/ refrangible blue4 ,mr4 ,hunt f\nd on a pap] prep>$ ) fluoride ( silv] t a yell[ l9e 0 impress$ on ! space occupi$ by ! yell[ rays1 a gre5 b& on ! space "u ! gre5 rays1 an int5se blue ?r\gh\t ! space on :i* ! blue & indigo rays fell1 & "u ! violet rays a ruddy br[n appe>$2 ^! col\rs rema9$ cle> & di/9ct aft] be+ kept two mon?s4 ,not)/&+ ! great v>iety 9 ! scale ( action ( ! sol> spectrum1 ! d>k5+ or deoxydiz+ pr9ciple t prevails 9 ! m refrangible "p r>ely surpasses or ev5 atta9s ! mean yell[ ray :i* is ! po9t ( maximum illum9ation2 x is g5]ally cut (f abruptly at t po9t :i* seems to =m a limit betwe5 ! oppos+ p[]s :i* prevail at ! two ends ( ! spectrum4 ,! blea*+ or oxydiz+ effect ( ! r$ rays on black5$ muriate ( silv] discov]$ by ,m4 ,ritt] ( ,j5a1 & ! re/oration by ! same rays ( discol\r$ gum guaiacum to its orig9al t9t by ,dr4 ,wolla/on1 h already be5 m5tion$ z giv+ ! fir/ indications ( t diff]5ce 9 ! mode ( action ( ! *emical rays at ! two ends ( ! visible spectrum1 n[ plac$ beyond a d\bt4 ,! action ex]t$ by ! less refrangible rays beyond & at ! r$ extremity ( ! sol> spectrum1 9 mo/ in/ances1 s f> f black5+ metallic salts1 protects !m f ! action ( ! diffus$ daylight3 b1 if ! prep>$ surface has already be5 black5$ by exposure to ! sun1 !y possess ! rem>kable prop]ty ( blea*+ x 9 "s cases1 & "u o!r circum/ances ( *ang+ ! black surface into a fi]y r$4 ,sir ,john ,h]s*el1 to :om we owe mo/ ( our k ( ! prop]ties ( ! *emical spectrum1 prep>$ a %eet ( pap] by wa%+ x ) muriate ( ammonia1 & !n ) two coats ( nitrate ( silv]2 on ?is surface he obta9$ an impression ( ! sol> spectrum exhibit+ a range ( col\rs v ne>ly correspond+ ) its natural hues4 ,b a v rem>kable ph5om5on occurr$ at ! end ( lea/ refrangibility2 ! r$ rays ex]t$ a protect+ influ5ce :i* pres]v$ ! pap] f ! *ange :i* x w\ld o!rwise h und]gone f ! deoxydiz+ influ5ce ( ! disp]s$ light :i* always surr\nds ! sol> spectrum1 & ?is ma9ta9$ its :it5ess4 ,sir ,john met ) ano!r in/ance on pap] prep>$ ) bromide ( silv]1 on :i* ! :ole ( ! space occupi$ by ! visible spectrum 0 d>k5$ d[n to ! v extremity ( ! r$ rays1 b an oxydiz+ action comm5c$ beyond ! extreme r$1 :i* ma9ta9$ ! :it5ess ( ! pap] to a consid]able di/ance beyond ! la/ traceable limit ( ! visible rays1 ?us ev9c+ decid$ly ! exi/5ce ( "s *emical p[] ov] a consid]able space beyond ! lea/ refrangible end ( ! spectrum4 ,mr4 ,hunt also f\nd t on ! ,dagu]reotype plate a p[]ful protect+ influ5ce is ex]cis$ by ! extreme r$ rays4 ,9 ^! cases ! r$ & ^? d>k rays beyond !m ex]t an action ( an opposite nature to t ( ! violet & lav5d] rays4 ,! lea/ refrangible "p ( ! sol> spectrum possesses also1 "u c]ta9 circum/ances1 a blea*+ prop]ty1 by :i* ! metallic salts are re/or$ to _! orig9al :it5ess aft] be+ black5$ by exposure to common daylight1 or to ! mo/ refrangible rays ( ! sol> spectrum4 ,pap] prep>$ ) iodide ( silv]1 :5 wa%$ ov] ) f]rocyanite ( pota%1 black5s rapidly :5 expos$ to ! sol> spectrum4 ,x beg9s 9 ! violet rays & ext5ds ov] all ! space occupi$ by ! d>k *emical rays1 & ov] ! :ole visible spectrum d[n to ! extreme r$ rays4 ,?is image is col\r$1 ! r$ rays giv+ a r$di% t9t & ! blue a bluei%4 ,9 a %ort "t a blea*+ process beg9s "u ! r$ rays1 & ext5ds upw>ds to ! gre51 b ! space occupi$ by ! extreme r$ is ma9ta9$ p]fectly d>k4 ,mr4 ,hunt f\nd t a simil> blea*+ p[] is ex]t$ by ! r$ rays on pap] prep>$ ) protocyanide ( potassium & gold ) a wa% ( nitrate ( silv]4 ,! application ( a mod]ately /rong hydriodate ( pota% to d>k5$ photographic pap] r5d]s x peculi>ly susceptible ( be+ :it5$ by fur!r exposure to light4 ,if pap] prep>$ ) bromide ( silv] be wa%$ ) f]rocyanate ( pota% :ile "u ! influ5ce ( ! sol> spectrum1 x is imm$iately d>k5$ ?r\gh\t ! "p expos$ to ! visible rays d[n to ! end ( ! r$1 "s slight int]f]5ce be+ p]ceptible ab\t ! region ( ! orange & yell[4 ,aft] ?is a blea*+ action beg9s ov] ! "p occupi$ by ! r$ rays1 :i* ext5ds to ! gre54 ,by long] exposure an oval spot beg9s aga9 to d>k5 ab\t ! c5tre ( ! blea*$ space2 b1 if ! pap] receive ano!r wa% ( ! hydriodate ( pota%1 ! blea*+ action ext5ds up f ! gre51 ov] ! region occupi$ by ! mo/ refrangible rays & consid]ably beyond !m1 ?us induc+ a negative action 9 ! mo/ refrangible "p ( ! spectrum4 ,9 c]ta9 circum/ances ! r$ rays1 in/ead ( re/or+ d>k5$ photographic pap] to its orig9al :it5ess1 produce a deep r$ col\r4 ,:5 ,sir ,john ,h]s*el receiv$ ! spectrum on pap] some:at discol\r$ by exposure to direct sun%9e1 in/ead ( :it5ess1 a r$ bord] 0 =m$ ext5d+ f ! space occupi$ by ! orange1 & ne>ly cov]+ t on :i* ! r$ fell4 ,:51 in/ead ( expos+ ! pap] 9 ! fir/ in/ance to direct sun%9e1 x 0 black5$ by ! violet rays ( a prismatic spectrum1 or by a sunbeam t _h und]gone ! absorptive action ( a solution ( ammonia-sulphate ( copp]1 ! r$ rays ( ! cond5s$ spectrum produc$ on x1 n :it5ess1 b a full & fi]y r$1 :i* occupi$ ! :ole space on :i* any ( ! visible r$ rays _h fall52 & ?is r$ rema9$ un*ang$1 h[ev] long ! pap] rema9$ expos$ to ! lea/ refrangible rays4 ,sunlight transmitt$ ?r\gh r$ glass produces ! same effect z ! r$ rays ( ! spectrum 9 ! =ego+ exp]im5t4 ,sir ,john ,h]s*el plac$ an engrav+ ov] a pap] black5$ by exposure to sun%9e1 cov]+ ! :ole ) a d>k r$-br[n glass previ\sly asc]ta9$ to absorb e ray beyond ! orange3 9 ?is way a photographic copy 0 obta9$ 9 :i* ! %ades 7 black1 z 9 ! orig9al engrav+2 b ! lights1 in/ead ( be+ :ite1 7 ( ! r$ col\r ( v5\s blood1 & no o!r col\r c\ld be obta9$ by exposure to light1 h[ev] long4 ,sir ,john asc]ta9$ t e "p ( ! spectrum impress$ by ! m refrangible rays is equally r$d5$1 or ne>ly s1 by ! subsequ5t action ( ! less refrangible2 ?us ! r$ rays h ! v rem>kable prop]ty ( assimilat+ to _! own col\r ! blackness already impress$ on photographic pap]4 ,t !re is a deoxydat+ prop]ty 9 ! m refrangible rays1 & an oxydat+ action 9 ! less refrangible "p ( ! spectrum1 is manife/ f ! black5+ ( "o & ! blea*+ effect ( ! o!r2 b ! peculi> action ( ! r$ rays 9 ! exp]im5ts m5tion$ %[s t "s o!r pr9ciple exi/s diff]5t f contr>iety ( action4 ,^! opposite qualities are balanc$ or neutraliz$ 9 ! region ( ! mean yell[ ray4 ,b1 al?\gh ?is is ! g5]al "* ( ! photographic spectrum1 "u c]ta9 circum/ances ev5 ! r$ rays h a deoxydat+ p[]1 :ile ! blue & violet ex]t a contr>y influ5ce2 b ^! are r>e exceptions4 ,! photographic action ( ! two portions ( ! sol> spectrum be+ s diff]5t1 ,sir ,john ,h]s*el tri$ ! effect ( _! unit$ action by sup]pos+ ! less refrangible "p ( ! spectrum ov] ! m refrangible portion by means ( two prisms2 & he ?us discov]$ t two rays ( diff]5t refrangibility1 & !re=e ( diff]5t l5g?s ( undulation1 act+ simultane\sly1 produce an effect :i* nei!r1 act+ sep>ately1 c d4 ,"s circum/ances t occurr$ dur+ ! analysis ( ! *emical spectrum seem to indicate an absorptive action 9 ! sun's atmosph]e4 ,! spectral image impress$ on pap] prep>$ ) nitrate ( silv] & ,ro*elle salt comm5c$ at1 or v little bel[1 ! mean yell[ ray1 ( a delicate lead col\r2 & :5 ! action 0 arre/$1 su* 0 ! "* ( ! :ole photographic spectrum4 ,b1 :5 ! light ( ! sol> spectrum 0 all[$ to cont9ue its action1 !re 0 obs]v$ to come on sudd5ly a new & mu* m int5se impression ( d>kness1 conf9$ 9 l5g? to ! blue & violet rays2 &1 :at is mo/ rem>kable1 conf9$ also 9 bread? to ! middle ( ! sun's image1 s f> at lea/ z to leave a bord] ( ! lead-col\r$ spectrum traceable1 n only r\nd ! cle> & well-def9$ convexity ( ! d>k int]ior spectrum at ! less refrangible end1 b also lat]ally along bo? its edges2 & ?is bord] 0 ! m easily trac$1 & less liable to be mi/ak51 f its /rik+ contra/ ( col\r ) ! int]ior spectrum1 ! =m] be+ lead gray1 ! latt] an extremely ri* deep velvety br[n4 ,! less refrangible end ( ?is int]ior br[n spectrum pres5t$ a %>ply t]m9at$ & regul>ly elliptical cont\r1 ! m refrangible a less decid$ "o4 8,x may seem too haz>d\s10 ,sir ,john cont9ues1 8to look = ! cause ( ?is v s+ul> ph5om5on 9 a real diff]5ce betwe5 ! *emical ag5cies ( ^? rays :i* issue f ! c5tral portion ( ! sun's disc1 & ^? :i*1 emanat+ f its bord]s1 h und]gone ! absorptive action ( a mu* great] dep? ( its atmosph]e2 & yet ,i confess myself some:at at a loss :at o!r cause to assign = x4 ,x mu/ suffice1 h[ev]1 to h ?r[n out ! h9t1 rem>k+ only1 t ,i h o!r1 & ,i am dispos$ to ?9k decisive1 evid5ce ( ! exi/5ce ( an absorptive sol> atmosph]e ext5d+ beyond ! lum9\s "o40 ,m4 ,arago obs]v$ t ! rays f ! c5tre ( ! sun h a great] photographic p[] ?an ^? f ! edges1 & ! photographic images ( ! sun1 tak5 on glass by ,m4 ,niepc1 7 blood-r$1 mu* deep] 9 ! c5tre1 & on "o occasion ! image 0 surr\nd$ by an auriol4 ,sev]al circum/ances concur 9 %[+ t !re are influ5ces also conc]n$ 9 ! transmission ( ! photographic action :i* h n yet be5 expla9$1 z1 = example1 ! influ5ce :i* ! "t ( ! day ex]cises on ! rapidity ) :i* photographic impressions are made1 ! sun be+ mu* less effective two h\rs aft] pass+ ! m]idian ?an two h\rs be=e4 ,!re is also reason to suspect t ! effect 9 "s way dep5ds on ! latitude1 s9ce a mu* long] "t is requir$ to obta9 an image "u ! bright skies ( ! tropics ?an 9 ,engl&2 & x is ev5 probable t !re is a diff]5ce 9 ! sun's light 9 high & l[ latitudes1 because an image ( ! sol> spectrum1 obta9$ on a ,dagu]reotype plate 9 ,virg9ia1 by ,dr4 ,drap]1 diff]$ f a spectral image obta9$ by ,mr4 ,hunt on a simil> plate 9 ,engl&4 ,! inactive spaces discov]$ 9 ! photographic spectrum by ,m4 ,e4 ,becqu]el1 simil> to ^? 9 ! lum9\s spectrum1 & co9cid+ ) !m1 is also a ph5om5on ( :i* no explanation has yet be5 giv52 possibly ! *emical rays may be absorb$ by ! atmosph]e ) ^? ( light4 ,al?\gh *emical action ext5ds ov] ! :ole lum9\s spectrum1 & mu* beyond x1 9 gradations ( m or less int5sity1 x is f\nd by c>eful inve/igation to be by no means cont9u\s2 num]\s inactive l9es cross x1 co9cid+ ) ^? 9 ! lum9\s image z f> z x ext5ds2 besides1 a v great numb] exi/ 9 ! portions t are obscure1 & :i* ov]lap ! visible "p4 ,!re are ?ree extraspectral l9es beyond ! r$1 & "s /rongly m>k$ gr\ps on ! obscure "p beyond ! violet2 b ! :ole numb] ( ^? inactive l9es1 especially 9 ! d>k spaces1 is s great t x is impossible to c\nt !m4 ,not)/&+ ?is co9cid5ce 9 ! inactive l9es ( ! two spectra1 photographic en]gy is indep5d5t ( bo? light & heat1 s9ce x ex]ts ! mo/ p[]ful influ5ce 9 ^? rays :]e !y are lea/1 & also 9 spaces :]e nei!r s5sibly exi/2 b ! transmission ( ! sun's light ?r\gh col\r$ m$ia makes t indep5d5ce q evid5t4 ,heat & light pass abundantly ?r\gh yell[ glass1 or a solution ( *romate ( pota%2 b ! great] "p ( ! *emical rays are exclud$1 & *lor9e gas dilut$ ) common air1 ?\gh highly p]vi\s to ! lum9\s & calorific pr9ciples1 has ! same effect4 ,sir ,john ,h]s*el f\nd t a slight degree ( yell[ ,london fog _h a simil> effect ) t ( pale yell[ m$ia3 he also rem>k$ t a weak solution ( azolitm9e 9 pota%1 :i* admits a great quantity ( gre5 light1 excludes *emical action2 & "s ye>s ago ! au?or1 :ile mak+ exp]im5ts on ! transmission ( *emical rays1 obs]v$ t gre5 glass1 col\r$ by oxide ( copp] ab\t ! #bj? ( an in* ?ick1 excludes ! photographic rays2 &1 z ,m4 ,melloni has %[n t sub/ance to be imp]vi\s to ! mo/ refrangible calorific rays1 x has ! prop]ty ( exclud+ ! :ole ( ! mo/ refrangible "p ( ! sol> spectrum1 visible & invisible4 ,gre5 mica1 if n too ?91 has also ! same effect1 :]eas ame?y/1 deep blue1 & violet-col\r$ glasses1 ?\gh !y transmit a v little light1 all[ ! *emical rays to pass freely4 ,?us light & photographic en]gy may be reg>d$ z di/9ct p>ts ( ! sol> beam1 & bo? be+ propagat$ by vibrations ( ! e!rial m$ium !y are m]ely motion4 ,excell5t images h be5 obta9$ ( ! moon 9 its diff]5t phases by ,pr(essor ,sec*i1 at ,rome2 c&lelight is ne>ly defici5t ( ! *emical rays4 ,h[ f> !y may influ5ce cry/allization & o!r molecul> arrangem5ts is unkn[n1 b _! p[] is univ]sal :]ev] ! sol> beam falls1 al?\gh _! effect only becomes evid5t 9 cases ( un/able molecul> equilibrium4 ,x is n by vision alone t a k ( ! sun's rays is acquir$3 t\* proves t !y h ! p[] ( rais+ ! temp]ature ( sub/ances expos$ to _! action4 ,sir ,william ,h]s*el discov]$ t rays :i* produce ! s5sation ( heat exi/ 9 ! sol> spectrum indep5d5t ( ^? ( light2 :5 he us$ a prism ( fl9t glass1 he f\nd t ! w>m rays are mo/ abundant 9 ! d>k space a little beyond ! r$ extremity ( ! spectrum1 t f !nce !y decrease t[>ds ! violet1 beyond :i* !y are ins5sible4 ,x may be conclud$ !re=e1 t ! calorific rays v>y 9 refrangibility1 & t ^? beyond ! extreme r$ are less refrangible ?an any rays ( light4 ,s9ce ,sir ,william ,h]s*el's "t x has be5 discov]$ t ! calorific spectrum exce$s ! lum9\s "o 9 l5g? 9 ! ratio ( #db to #be1 b ! mo/ s+ul> ph5om5on is its want ( cont9uity4 ,sir ,john ,h]s*el black5$ ! "u side ( a %eet ( v ?9 :ite pap] by ! smoke ( a lamp1 &1 hav+ expos$ ! :ite side to ! sol> spectrum1 he drew a bru% dipp$ 9 _s ( w9e ov] x1 by :i* ! pap] assum$ a black hue :5 suffici5tly saturat$4 ,! heat 9 ! spectrum evaporat$ ! _s fir/ on ^? p>ts ( ! pap] :]e x fell ) greate/ int5sity1 !reby re/or+ _! :ite col\r1 & he ?us discov]$ t ! heat increases uni=mly & gradually ?r\gh\t ! lum9\s spectrum1 & t x comes to a maximum & =ms a spot at a consid]able di/ance beyond ! extreme r$4 ,x !n decreases1 b aga9 increas+ x =ms a second maximum spot1 aft] :i* x ceases altoge!r ?r\gh a %ort space1 b is aga9 r5ew$ & =ms two m insulat$ spots1 & ev5 a fif? may be trac$ at a little di/ance f ! latt]4 ,^! circum/ances are probably ow+ to ! absorb+ action ( ! atmosph]es ( ! sun & e>?4 8,! effect ( ! =m]10 says ,sir ,john1 8is beyond our control1 unless we c\ld c>ry our exp]im5ts to su* a po9t ( delicacy z to op]ate sep>ately on rays emanat+ f ! c5tre & bord]s ( ! sun's disc2 t ( ! e>?'s1 ?\gh x _c be elim9at$ any m ?an 9 ! case ( ! sun's1 may yet be v>i$ to a consid]able ext5t by exp]im5ts made at great elevations1 "u a v]tical sun1 & comp>$ ) o!rs :]e ! sun is m oblique1 ! situation l[]1 & ! atmosph]ic pressure ( a tempor>ily high am\nt4 ,%\ld x be f\nd t ?is cause is 9 reality conc]n$ 9 ! production ( ! spots1 we %\ld see reason to believe t a l>ge portion ( sol> heat nev] rea*es ! e>?'s surface1 & t :at is incid5t on ! summits ( l(ty m\nta9s diff]s n only 9 quantity b also 9 quality f :at ! pla9s receive40 ,a rem>kable phosphoresc5t prop]ty 0 discov]$ by ,m4 ,e4 ,becqu]el 9 ! sol> spectrum4 ,two lum9\s b&s sep>at$ by a d>k "o are excit$ by ! sol> spectrum on pap] cov]$ ) a solution ( gum arabic1 & /rew$ ) p[d]$ sulphuret ( calcium or ,canton's phosphorus4 ,"o ( ! lum9\s b&s occupies ! space "u ! lea/ refrangible violet rays1 & ! o!r t beyond ! lav5d] rays1 s t ! d>k b& lies "u ! extreme violet & lav5d] rays4 ,:5 ! action ( ! light is cont9u$1 ! :ole surface beyond ! lea/ refrangible violet %9es1 ! lum9\s b&s already m5tion$ brighte/2 b all ! space f ! lea/ refrangible violet to ! extreme r$ rema9s d>k4 ,if ! surface1 prep>$ ei!r ) ! sulphuret ( calcium or ,bologna /one1 be expos$ to ! sun's light = a little "t1 x becomes lum9\s all ov]2 b :51 9 ?is /ate1 a sol> spectrum is ?r[n ^u x1 ! :ole rema9s lum9\s except ! "p f ! lea/ refrangible violet to ! extreme r$1 on :i* space ! light is ext+ui%$2 & :5 ! temp]ature ( ! surface is rais$ by a lamp1 ! bright p>ts become m lum9\s & ! d>k p>ts rema9 d>k4 ,glass /a9$ by ! protoxide ( copp]1 :i* transmits only ! r$ & orange rays1 has ! same effect ) ! less refrangible "p ( ! spectrum2 h5ce !re c be no d\bt t ! mo/ refrangible & obscure rays ( ! spectrum excite phosphoresc5ce1 :ile all ! less refrangible rays ( light & heat ext+ui% x4 ,pap] prep>$ ) ! sulphuret ( b>ium1 :5 "u ! sol> spectrum1 %[s only "o space ( maximum lum9\s int5sity1 & ! de/roy+ rays are ! same z 9 ! sulphuret ( calcium4 ,?us ! obscure rays beyond ! extreme violet produce light1 :ile ! lum9\s rays ext+ui% x4 ,! phosphoric spectrum has inactive l9es :i* co9cide ) ^? 9 ! lum9\s & *emical spectra1 at lea/ z f> z x ext5ds2 b 9 ord] to be se5 ! spectrum mu/ be receiv$ = a few seconds ^u ! prep>$ surface ?r\gh an ap]ture 9 a d>k room1 !n ! ap]ture mu/ be clos$1 & ! temp]ature ( ! surface rais$ two or ?ree hundr$ degrees2 ! phosphoresc5t p>ts !n %9e brilliantly & ! d>k l9es appe> black4 ,s9ce ! p>ts ( simil> refrangibility 9 diff]5t spectra are trav]s$ by ! same d>k l9es1 rays ( ! same refrangibility are probably absorb$ at ! same "t by ! diff]5t m$ia ?r\gh :i* !y pass4 ,x appe>s f ! exp]im5ts ( ,,mm4 ,becqu]el & ,biot1 t electrical di/urbances produce ^! phosphoresc5t effects4 ,!re is ?us a my/]i\s connexion betwe5 ! mo/ refrangible rays & electricity :i* ! exp]im5ts ( ,m4 ,e4 ,becqu]el confirm1 %[+ t electricity is develop$ dur+ *emical action by ! violet rays1 t x is feebly develop$ by ! blue & indigo1 b t none is excit$ by ! less refrangible "p ( ! spectrum4 ,a s]ies ( exp]im5ts by ,sir ,john ,h]s*el h disclos$ a new set ( obscure rays 9 ! sol> spectrum1 :i* seem to be> ! same relation to ^? ( heat t ! photographic or *emical rays be> to ! lum9\s4 ,!y are situate 9 t "p ( ! spectrum :i* is occupi$ by ! less refrangible visible col\rs1 & h be5 nam$ by _! discov]] ,p>a!rmic rays4 ,x mu/ be held 9 remembrance t ! region ( greate/ heat 9 ! sol> spectrum lies 9 ! d>k space beyond ! visible r$4 ,n[1 ,sir ,john ,h]s*el f\nd t 9 exp]im5ts ) a solution ( gum guaiacum 9 soda1 :i* gives ! pap] a gre5 col\r1 ! gre51 yell[1 orange1 & r$ rays ( ! spectrum inv>iably dis*>g$ ! col\r1 :ile no effect 0 produc$ by ! extra-spectral rays ( heat1 :i* ought to h _h ! greate/ effect _h heat be5 ! cause ( ! ph5om5on4 ,:5 an aque\s solution ( *lor9e 0 p\r$ ov] a slip ( pap] prep>$ ) gum guaiacum dissolv$ 9 soda1 a col\r v>y+ f a deep some:at gre5i% hue to a f9e cele/ial blue 0 giv5 to x2 &1 :5 ! sol> spectrum 0 ?r[n on ! pap] :ile moi/1 ! col\r 0 dis*>g$ f all ! space "u ! less refrangible lum9\s rays1 at ! same "t t ! m di/ant !rmic rays beyond ! spectrum evaporat$ ! moi/ure f ! space on :i* !y fell2 s t ! heat spots became app>5t4 ,b ! spots disappe>$ z ! pap] dri$1 leav+ ! surface un*ang$2 :ile ! photographic impression )9 ! visible spectrum increas$ 9 int5sity2 ! non-lum9\s !rmic rays1 ?\gh evid5tly active z to heat1 7 yet incapable ( effect+ t peculi> *emical *ange :i* o!r rays ( mu* less heat+ p[] 7 all ! "t produc+4 ,sir ,john hav+ asc]ta9$ t an artificial heat f #ahj to #bhj ( ,fahr5heit *ang$ ! gre5 t9t ( gum guaiacum to its orig9al yell[ hue :5 moi/1 b t x _h no effect :5 dry1 he !re=e tri$ :e!r heat f a hot iron appli$ to ! back ( ! pap] us$ 9 ! la/-m5tion$ exp]im5t :ile "u ! influ5ce ( ! sol> spectrum might n assi/ ! action ( ! calorific rays2 b1 in/ead ( do+ s1 x greatly accel]at$ ! discoloration ov] ! spaces occupi$ by ! less refrangible rays1 b _h no effect on ! extra-spectral region ( maximum heat4 ,obscure t]re/rial heat1 !re=e1 is capable ( assi/+ & be+ assi/$ 9 effect+ ?is peculi> *ange by ^? rays ( ! spectrum1 :e!r lum9\s or !rmic1 :i* occupy its r$1 yell[1 & gre5 regions2 :ile1 on ! o!r h&1 x receives no su* assi/ance f ! purely !rmic rays beyond ! spectrum act+ "u simil> circum/ances & 9 an equal /ate ( cond5sation4 ,! conclusions drawn f ^! exp]im5ts are confirm$ by t :i* foll[s3 a photographic picture =m$ on pap] prep>$ ) a mixture ( ! solutions ( ammonia-citrate ( iron & f]ro-sesquicyanite ( pota% 9 equal p>ts1 !n ?r[n into wat] & aft]w>ds dri$1 w be blue & negative1 t is to say1 ! lights & %ad[s w be ! rev]se ( :at !y are 9 nature4 ,if 9 ?is /ate ! pap] be wa%$ ) a solution ( proto-nitrate ( m]cury1 ! picture w be dis*>g$2 b if x be well wa%$ & dri$1 & a hot smoo?+-iron pass$ ov] x1 ! picture in/antly reappe>s1 n blue1 b br[n2 if kept "s weeks 9 ?is /ate 9 p]fect d>kness betwe5 ! leaves ( a portfolio1 x fades1 & almo/ entirely vani%es1 b a fre% application ( heat re/ores x to its full orig9al int5sity4 ,?is curi\s *ange is n ! effect ( light1 at lea/ n ( light alone4 ,a c]ta9 temp]ature mu/ be atta9$1 & t suffices 9 total d>kness2 yet1 on expos+ to a v conc5trat$ spectrum a slip ( ! pap] us$ 9 ! la/ exp]im5t1 aft] ! uni=m blue col\r has be5 dis*>g$ & a :ite gr\nd left1 ?is :it5ess is *ang$ to br[n ov] ! :ole region ( ! r$ & orange rays1 b n beyond ! lum9\s spectrum4 ,sir ,john !nce concludes3--#a/4 ,t x is ! heat ( ^! rays1 n _! light1 :i* op]ates ! *ange2 #bndly4 ,t ?is heat possesses a peculi> *emical quality :i* is n possess$ by ! purely calorific rays outside ( ! visible spectrum1 ?\gh f> m int5se2 &1 #crdly4 ,t ! heat radiat$ f obscurely hot iron ab\nds especially 9 rays analog\s to ^? ( ! region ( ! spectrum above indicat$4 ,ano!r in/ance ( ^! s+ul> trans=mations may be notic$4 ,! pictures =m$ on cyanotype pap] r5d]$ m s5sitive by ! addition ( corrosive sublimate are blue on a :ite gr\nd & positive1 t is1 ! lights & %ad[s are ! same z 9 nature1 b1 by ! application ( heat1 ! col\r is *ang$ f blue to br[n1 f positive to negative2 ev5 by keep+ 9 d>kness ! blue col\r is re/or$1 z well z ! positive "*4 ,sir ,john attributes ?is1 z 9 ! =m] in/ance1 to c]ta9 rays1 :i*1 reg>d$ z rays ( heat or light1 or ( "s influ5ce sui g5]is accompany+ ! r$ & orange rays ( ! spectrum1 are also copi\sly emitt$ by bodies heat$ %ort ( r$ness4 ,he ?9ks x probable t ^! invisible p>a!rmic rays are ! rays :i* radiate f molecule to molecule 9 ! int]ior ( bodies1 t !y det]m9e ! dis*>ge ( vegetable col\rs at ! boil+ temp]ature1 & also ! innum]able atomic trans=mations ( organic bodies :i* take place at ! temp]ature bel[ r$ness1 t !y are di/9ct f ^? ( pure heat1 & t !y are suffici5tly id5tifi$ by ^! *>act]s to become legitimate objects ( sci5tific discussion4 ,! calorific & p>a!rmic rays appe> to be intimately connect$ ) ! discov]ies ( ,messrs4 ,drap] & ,mos]4 ,dagu]re has %[n t ! action ( light on ! iodide ( silv] r5d]s x capable ( cond5s+ ! vap\r ( m]cury :i* adh]es to ! p>ts affect$ by x4 ,pr(essor ,mos] ( ,knigsb]g has prov$ t ! same effect is produc$ by ! simple contact ( bodies1 & ev5 by _! v ne> juxtaposition1 & t 9 total d>kness z well z 9 light4 ,?is discov]y he ann\nc$ 9 ! foll[+ words3--8,if a surface has be5 t\*$ 9 any p>ticul> p>ts by any body1 x acquires ! prop]ty ( precipitat+ all vap\rs1 & ^! adh]e to x or comb9e *emically ) x on ^! spots diff]5tly f :at !y d on ! unt\*$ p>ts40 ,if we write on a plate ( glass or any smoo? surface :atev] ) blott+-pap]1 a bru%1 or any?+ else1 & !n clean x1 ! *>act]s always reappe> if ! plate or surface be brea!d ^u1 & ! same effect may be produc$ ev5 on ! surface ( m]cury2 nor is absolute contact necess>y4 ,if a scre5 cut 9 a patt]n be held ov] a poli%$ metallic surface at a small di/ance1 & ! :ole brea!d on1 aft] ! vap\r has evaporat$ s t no trace is left on ! surface1 ! patt]n comes out :5 x is brea!d on aga94 ,pr(essor ,mos] prov$ t bodies ex]t a v decid$ influ5ce ^u ea* o!r1 by plac+ co9s1 cut /ones1 pieces ( horn1 & o!r sub/ances1 = a %ort "t on a w>m metallic plate3 :5 ! sub/ance 0 remov$1 no impression appe>$ on ! plate till x 0 brea!d ^u or expos$ to ! vap\r ( m]cury1 & !n ^! vap\rs adh]$ only to ! p>ts :]e ! sub/ance _h be5 plac$1 mak+ di/9ct images1 :i* 9 "s cases 7 p]man5t aft] ! vap\r 0 remov$4 ,simil> impressions 7 obta9$ on glass & o!r sub/ances ev5 :5 ! bodies 7 n 9 contact1 & ! results 7 ! same :e!r ! exp]im5ts 7 p]=m$ 9 light or 9 d>kness4 ,mr4 ,grove f\nd1 :5 plates ( z9c & copp] 7 closely approximat$1 b n 9 contact1 & sudd5ly sep>at$1 t "o 0 positively & ! o!r negatively electric2 :5ce he inf]r$ t ! int]v5+ m$ium 0 ei!r pol>is$1 or t a radiation analog\s1 if n id5tical1 ) t :i* produces ,mos]'s images takes place f plate to plate4 ,mr4 ,hunt has %[n t _m ( ^! ph5om5a dep5d on diff]5ce ( temp]ature1 & t1 9 ord] to obta9 good impressions1 dissimil> metals mu/ be us$4 ,= example1 gold1 silv]1 bronze1 & copp] co9s 7 plac$ on a plate ( copp] too hot to be t\*$1 & all[$ to rema9 till ! plate cool$3 all ! co9s _h made an impression1 ! di/9ctness & int5sity ( :i* 7 9 ! ord] ( ! metals nam$4 ,:5 ! plate 0 expos$ to ! vap\r ( m]cury ! result 0 ! same1 b1 :5 ! vap\r 0 wip$ (f1 ! gold & silv] co9s only _h left p]man5t images on ! copp]4 ,^! impressions are (t5 m9utely p]fect1 :e!r ! co9s are 9 actual contact ) ! plate or "o-eigh? ( an in* above x4 ,! mass ( ! metal has a mat]ial influ5ce on ! result2 a l>ge copp] co9 makes a bett] impression on a copp] plate ?an a small silv] co94 ,:5 co9s ( diff]5t metals are plac$ on ! same plate !y int]f]e ) ea* o!r4 ,:51 in/ead ( be+ heat$1 ! copp] plate 0 cool$ by a freez+ mixture1 & bad conductors ( heat laid ^u x1 z wood1 pap]1 glass1 c41 ! result 0 simil>4 ,mr4 ,hunt1 obs]v+ t a black sub/ance leaves a /rong] impression on a metallic surface ?an a :ite1 appli$ ! prop]ty to ! art ( copy+ pr9ts1 woodcuts1 writ+1 & pr9t+1 on copp] amalgamat$ on "o surface & highly poli%$1 m]ely by plac+ ! object to be copi$ smoo?ly on ! metal1 & press+ x into close contact by a plate ( glass3 aft] "s h\rs ! plate is subject$ to ! vap\r ( m]cury1 & aft]w>ds to t ( iod9e1 :5 a black & accurate impression ( ! object comes out on a grey gr\nd4 ,effects simil> to ^? attribut$ to heat may also be produc$ by electricity4 ,mr4 ,k>/51 by plac+ a glass plate ^u "o ( metal1 & on ! glass plate a m$al subject$ to dis*>ges ( electricity1 f\nd a p]fect image ( ! m$al impress$ on ! glass1 :i* c\ld be br\ght into evid5ce by ei!r m]cury or iod9e2 &1 :5 sev]al plates ( glass 7 int]pos$ betwe5 ! m$al & ! metallic plate1 ea* plate ( glass receiv$ an image on its upp] surface aft] ! passage ( electrical dis*>ges4 ,^! dis*>ges h ! rem>kable p[] ( re/or+ impressions t h be5 long oblit]at$ f plates by poli%+--a pro( t ! di/urbances ^u :i* ^! ph5om5a dep5d are n conf9$ to ! surface ( ! metals1 b t a v decid$ molecul> *ange has tak5 place to a consid]able dep?4 ,mr4 ,hunt's exp]im5ts prove t ! electro-negative metals make ! mo/ decid$ images ^u electro-negative plates1 & vice v]s4 ,m4 ,matteucci has %[n t a dis*>ge ( electricity does n visibly affect a poli%$ silv] plate1 b t x produces an alt]ation :i* r5d]s x capable ( cond5s+ vap\r4 ,! impression ( an engrav+ 0 made by lay+ x face d[nw>ds on a silv] plate iodiz$1 & plac+ an amalgamat$ copp] plate ^u x2 x 0 left 9 d>kness fifte5 h\rs1 dur+ :i* "t an impression ( ! engrav+ _h be5 made on ! amalgamat$ plate ?r\gh ! pap]4 ,an iodiz$ silv] plate 0 plac$ 9 d>kness ) a coil ( /r+ laid on x1 & ) a poli%$ silv] plate susp5d$ "o-eigh? ( an in* above x3 aft] f\r h\rs !y 7 expos$ to ! vap\rs ( m]cury1 :i* became uni=mly deposit$ on ! iodiz$ plate1 b on ! silv] "o !re 0 a %>p image ( ! /r+1 s t ?is image 0 =m$ 9 ! d>k1 & ev5 )\t contact4 ,co9s or o!r objects leave _! impressions 9 ! same mann] ) p]fect %>pness & accuracy1 :5 br\ght out by vap\r )\t contact1 9 d>kness1 & on simple metals4 ,r$ & orange col\r$ m$ia1 smok$ glass1 & all bodies t transmit or absorb ! hot rays freely1 leave /rong impressions on a plate ( copp]1 :e!r !y be 9 contact or "o-eigh? ( an in* above x4 ,heat mu/ be conc]n$ 9 ?is1 = a sol> spectrum conc5trat$ by a l5s 0 ?r[n on a poli%$ plate ( copp]1 & kept on ! same spot by a helio/at = two or ?ree h\rs3 :5 expos$ to m]curial vap\r1 a film ( ! vap\r cov]$ ! plate :]e ! diffus$ light :i* always accompanies ! sol> spectrum _h fall54 ,on ! obscure space occupi$ by ! maximum heat+ p[] ( ,sir ,william ,h]s*el1 & also on ! great heat spot 9 ! !rmic spectrum ( ,sir ,john ,h]s*el1 ! cond5sation ( ! m]cury 0 s ?ick t x /ood out a di/9ct :ite spot on ! plate1 :ile ov] ! :ole space t _h be5 "u ! visible spectrum ! quantity ( vap\r 0 mu* less ?an t :i* cov]$ ! o!r p>ts1 af=d+ di/9ct evid5ce ( a negative effect 9 ! lum9\s spectrum & ( ! p[] ( ! hot rays1 :i* is n always conf9$ to ! surface ( ! metal1 s9ce 9 _m in/ances ! impressions p5etrat$ to a consid]able dep? bel[ x1 & consequ5tly 7 p]man5t4 ,sev]al ( ^! s+ul> effects appe> to be ow+ to ! mutual action ( molecules 9 contact :ile 9 a diff]5t /ate1 :e!r ( electricity or temp]ature3 o!rs cle>ly po9t at "s unkn[n influ5ce ex]t$ betwe5 surfaces at a di/ance1 & affect+ _! molecul> /ructure3 possibly x may be ! p>a!rmic rays1 :i* h a peculi> *emical action ev5 9 total d>kness4 ,9 ! la/ exp]im5t ! effect is c]ta9ly produc$ by ! positive portion ( "o ( ^? rem>kable antagoni/ pr9ciples :i* *>act]ise ! sol> spectrum4 ,?us x appe>s t ! prism resolves ! pure :ite sunbeam into ?ree sup]pos$ spectra1 ea* v>y+ 9 refrangibility & int5sity ?r\gh\t its :ole l5g?2 ! visible "p is ov]lapp$ at "o end by ! *emical or photographic rays1 & at ! o!r by ! !rmic1 b ! two latt] s mu* exce$ ! visible "p1 t ! l9e> dim5sions ( ! ?ree--! lum9\s1 !rmic1 & photographic--are 9 proportion to ! numb]s #be1 #dbaj1 & #eeaj1 s t ! :ole sol> spectrum is twice z long z its visible "p4 ,! two extremities ex]t a decid$ antagoni/ en]gy4 ,! lea/ refrangible lum9\s rays oblit]ate ! action ( ! photographic rays1 :ile ! latt] produce phosphoresc5t light1 :i* is ext+ui%$ by ! lea/ refrangible lum9\s rays4 ,accord+ to ,mr4 ,hunt's exp]im5t1 ! hot rays cond5se m]curial vap\r on a poli%$ metallic plate1 :ile ! lum9\s rays prev5t its =mation4 ,electricity is excit$ by ! *emical rays1 :ile ! p>a!rmic are f\nd 9 ! less refrangible rays alone4 ,ea* ( ! spectra is cross$ by col\r$ & rayless l9es peculi> to itself1 & ^! are trav]s$ at "r angles by innum]able d>k l9es ( v>i\s bread?s1 ! :ole =m+ an inexpressibly wond]ful & glori\s creation4 ,! arrangem5t v>ies a little accord+ to ! mat]ial ( ! prism & ! mann] ( produc+ ! spectrum1 z 9 t obta9$ by ,pr(essor ,drap] f diffract$ light4 ,x 0 =m$ by a beam diffract$ by pass+ ?r\gh a nett+ ( f9e wire1 or by reflection f a poli%$ surface ( /eel1 hav+ f9e p>allel l9es drawn on x4 ,?is diffract$ spectrum is divid$ into two equal p>ts 9 ! c5tre ( ! yell[2 & z 9 ! prismatic spectrum1 "o half is antagoni/ to ! o!r half1 ! r$ or negative end undo+ :at ! positive or violet end has done4 ,! c5tre ( ! yell[ is ! hotte/ "p1 & ! heat decreases to bo? extremities4 ,a l9e ( cold is suppos$ to exi/ on ?is spectrum answ]+ to ,fraunh(]'s d>k l9e ,h4 ,! undulations ( ! e!real m$ium :i* con/itute a sunbeam mu/ be inf9itely v>i$1 ea* influ5ce hav+ a vibration peculi> to itself4 ,^? ( light are c]ta9ly transv]se to ! direction ( ! ray2 :ile ,pr(essor ,drap] believes t ^? ( heat are normal1 t is1 9 ! direction ( ! ray1 l ^? ( s\nd4 ,a d\bt exi/s :e!r ! vibrations ( pol>is$ light are p]p5dicul> to ! plane ( pol>isation or 9 t plane4 ,pr(essor ,/okes ( ,cambridge has come to ! conclusion1 bo? f ! diffract$ spectrum & !ory1 t !y are p]p5dicul> to ! plane ( pol>isation1 b ,m4 ,holtzmann is ( op9ion t !y are 9 t plane1 s ! subject is /ill op5 to discussion4 ,,section ,,xxv4 ,size & ,con/itution ( ! ,sun--,! ,sol> ,spots--,int5sity ( ! ,sun's ,light & ,heat--,! ,sun's ,atmosph]e--,8 influ5ce on ! ,planets--,atmosph]es ( ! ,planets--,! ,moon has none--,lun> heat--,! ,diff]5tial ,telescope--,temp]ature ( ,space--,int]nal ,heat ( ! ,e>?--,zone ( con/ant ,temp]ature--,increase ( ,heat ,) ! ,dep?--,c5tral ,heat--,volcanic ,action--,quantity ( ,heat receiv$ f ! ,sun--,isogeo!rmal ,l9es--,l9e ( p]petual ,congelation--,climate--,iso!rmal ,l9es--,same quantity ( ,heat annually receiv$ & radiat$ by ! ,e>?4 ,,! sun is a globe #hhj1jjj miles 9 diamet]3 :at 8 body may be x is impossible to conjecture1 b x seems to be a d>k mass surr\nd$ by an ext5sive atmosph]e at a c]ta9 height 9 :i* !re is a /ratum ( lum9\s cl\ds :i* con/itutes ! photosph]e ( ! sun4 ,above x rises ! true sol> atmosph]e1 visible z an aureola or corona dur+ annul> & total eclipses1 & probably ! cause ( ! peculi> ph5om5a 9 ! photographic image ( ! sun already m5tion$4 ,?r\gh occasional op5+s 9 ! photosph]e or mottl$ ocean ( flame1 ! d>k nucleus appe>s l black spots1 (t5 ( enorm\s size4 ,^! spots are almo/ always compris$ )9 a zone ( ! sun's surface1 ^: bread? measur$ on a sol> m]idian does n ext5d beyond #cj-a_/b on ea* side ( 8 equator1 ?\gh !y h be5 se5 at a di/ance ( #ci-a_/b4 ,! d>k c5tral "p ( ! spots is surr\nd$ by a succession ( obscure cl\dy envelopes increas+ 9 brightness up to a p5umbra1 sometimes !re are ?ree or m %ades1 b x requires a good telescope to di/+ui% ! int]m$iate ones4 ,! spots gradually increase 9 size & numb] f ye> to ye> to a maximum1 & !n z gradually decrease to a m9imum1 accompli%+ regul> vicissitudes 9 p]iods ( ab\t elev5 ye>s1 & are s+ul>ly connect$ ) ! cycles ( t]re/rial magnetism4 ,f _! ext5sive & rapid *anges1 !re is e reason to believe t ! ext]ior & inc&esc5t "p ( ! sun is gase\s4 ,d\bts h aris5 z to ! uni=mity ( ! quantity ( heat emitt$ by ! sun4 ,sir ,william ,h]s*el 0 ! fir/ to suspect t x 0 affect$ by ! quantity & magnitude ( ! spots on 8 surface2 ,pr(essor ,sec*i has obs]v$ t ! spots are less hot ?an ! lum9\s "p2 & n[ ,pr(essor ,wolf has p]ceiv$ t ! am\nt ( heat emitt$ by ! sun v>ies p]iodically ) ! spots e #aaaa ye>s1 or ne>ly n9e times 9 a c5tury1 beg9n+ at ! comm5cem5t ( ! pres5t "o4 ,he has discov]$ a sub-p]iod 9 t ( ! spots1 :i* no d\bt has an effect on ! quantity ( sol> heat4 ,s ! unacc\ntable vicissitudes 9 ! temp]ature ( diff]5t ye>s may ultimately be f\nd to dep5d ^u ! con/itution ( ! sun himself4 ,! int5sity ( ! sun's light dim9i%es f ! c5tre to ! circumf]5ce ( ! sol> disc4 ,8 direct light has be5 e/imat$ to be equal to t ( #eefc wax c&les ( mod]ate size plac$ at ! di/ance ( "o foot f an object2 t ( ! moon is probably only equal to ! light ( "o c&le at ! di/ance ( #ab feet3 consequ5tly ! light ( ! sun is m ?an ?ree hundr$ ?\s& times great] ?an t ( ! moon4 ,accord+ to ,pr(essor ,sec*i's exp]im5ts at ,rome1 ! heat ( ! sol> image is almo/ twice z great at ! c5tre z at ! edge4 ,! maximum heat1 h[ev]1 is n 9 ! c5tre1 b 9 ! sol> equator1 & ! spots are less hot ?an ! re/ ( ! surface4 ,! oceans ( light & heat probably aris+ f electric or *emical processes ( imm5se en]gy t cont9ually take place at ! sun's surface 7,n4 #bag7 are transmitt$ 9 undulations by ! e!real m$ium 9 all directions2 b not)/&+ ! sun's magnitude & ! inconceivable int5sity ( light & heat t mu/ exi/ at 8 surface1 z ! int5sity ( bo? dim9i%es z ! squ>e ( ! di/ance increases1 8 k9dly influ5ce c h>dly be felt at ! b\nd>ies ( our sy/em4 ,9 ,uranus ! sun mu/ be se5 l a small brilliant /> n above ! hundr$ & fiftie? "p z bright z he appe>s to u1 b t is #bjjj times bright] ?an our moon1 s t he is really a sun to ,uranus1 & may imp>t "s degree ( w>m?4 ,b if we consid] t wat] w\ld n rema9 fluid 9 any "p ( ,m>s1 ev5 at 8 equator1 & t1 9 ! temp]ate zones ( ! same planet1 ev5 alcohol & quicksilv] w\ld freeze1 we may =m "s idea ( ! cold t mu/ reign 9 ,uranus & ,neptune4 ,! climate ( ,v5us m ne>ly resembles t ( ! e>?1 ?\gh1 except+ at h] poles1 mu* too hot = animal & vegetable life su* z !y exi/ "h1 = %e receives sev5 times z mu* light & heat z ! e>? does2 b 9 ,m]cury ! mean heat f ! int5sity ( ! sun's rays mu/ be above t ( boil+ quicksilv]1 & wat] w\ld boil ev5 at 8 poles4 ,?us ! planets1 ?\gh k9dr$ ) ! e>? 9 motion & =m1 are1 accord+ to our exp]i5ce1 totally unfit = ! habitation ( su* a be+ z man1 unless inde$ _! temp]ature %\ld be modifi$ by circum/ances ( :i* we are n aw>e1 & :i* may increase or dim9i% ! s5sible heat s z to r5d] !m habitable4 ,9 our utt] ignorance x may be obs]v$1 t ! e>?1 if visible at all f ,neptune1 c only be a m9ute telescopic object2 t f ! ne>e/ fix$ /> ! sun mu/ dw9dle to a m]e po9t ( light2 t ! :ole sol> sy/em w\ld !re be hid by a spid]'s ?read2 & t ! />ry firmam5t itself is only ! fir/ s]ies ( />ry sy/ems1 ! numb]s ( :i* are b\nd$ alone by ! imp]fection ( our space-p5etrat+ in/rum5ts4 ,9 ?is ov]:elm+ maje/y ( creation1 x seems ra% to affirm t ! e>? alone is inhabit$ by intellig5t be+s1 & ?us to limit ! ,omnipot5t1 :o has made no?+ 9 va94 ,sev]al ( ! planets h ext5sive & d5se atmosph]es3 accord+ to ,s*rot] ! atmosph]e ( ,c]es is m ?an #ffh miles high1 & t ( ,pallas has an elevation ( #dfe miles1 b n a trace ( an atmosph]e c be p]ceiv$ r\nd ,ve/a4 ,! attraction ( ! e>? has probably depriv$ ! moon ( h]s1 = ! refractive p[] ( ! air at ! surface ( ! e>? is at lea/ a ?\s& times z great z at ! surface ( ! moon3 ! lun> atmosph]e mu/ !re=e be ( a great] degree ( r>ity ?an c be produc$ by our be/ air-pumps4 ,?is is confirm$ by ,arago's obs]vations dur+ a sol> eclipse1 :5 no trace ( a lun> atmosph]e c\ld be se54 ,s9ce !n1 h[ev]1 "s indications ( air h be5 p]ceiv$ 9 ! lun> valleys4 ,9 tak+ photographic images ( ! moon & ,jupit] at ,rome1 ,pr(essor ,sec*i f\nd t ! light ( ! full moon is to t ( ! qu>t] moon z #c to #a4 ,jupit] gives a photographic image z bright & vigor\s z ! brighte/ "p ( ! moon2 b al?\gh ! light ( ,jupit] is less ?an t ( ! moon1 he is ne>ly five times f>!r f ! sun2 & z light dim9i%es z ! squ>e ( ! di/ance increases1 ! light ( ,jupit] is proportionally great] ?an t ( ! moon1 consequ5tly ,jupit]'s atmosph]e reflects m light ?an ! d>k volcanic soil ( ! moon2 ?us ,pr(essor ,sec*i obs]ves photography may 9 "t reveal ! quality ( ! mat]ials ( :i* ! cele/ial bodies are =m$4 ,! effect ( ! e>?'s atmosph]e on lun> heat is rem>kable4 ,pr(essor ,=bes prov$ t ! direct light ( ! full moon is incapable ( rais+ a !rmomet] ! "o ?ree ?\s&? "p ( a ,c5tigrade degree1 at lea/ 9 ,engl&2 b at an elevation ( #hhgj feet on ! ,peak ( ,t5]iffe1 ,mr4 ,piazzi ,smy? f\nd a v s5sible heat f ! moon1 al?\gh %e 0 !n #ai s\? ( ! equator2 s x is no d\bt absorb$ by our atmosph]e at l[] levels4 ,"s exce$+ly int]e/+ exp]im5ts might be made by means ( a telescope hav+ a prism atta*$ to its objective extremity1 & furni%$ ) a micromet]1 because by x ! diff]5ce ( ! illum9ation ( objects might be det]m9$ ) extreme accuracy--z = example1 ! comp>ative int5sity betwe5 ! bright & d>k p>ts ( ! moon1 ! comp>ative int5sity ( ! sol> light reflect$ by ! moon1 & ! lumire c5dr1 or ! light ( ! e>? reflect$ on ! moon1 :5ce a comp>ison might be made betwe5 ! light ( ! sun & t ( ! e>?4 ,h5ce also x might be kn[n :e!r ! t]re/rial hemisph]es successively visible f ! moon are m or less lum9\s1 accord+ z !y conta9 m l& or wat]1 & at ! same "t x might be possible to appreciate ! m or less cl\dy or cle> /ate ( our atmosph]e1 s t 9 "t we might ultimately f9d 9 ! lumire c5dr ( ! moon data ^u ! mean diaphaneity ( diff]5t t]re/rial hemisph]es :i* are ( diff]5t temp]atures4 ,x is f\nd by exp]i5ce t heat is develop$ 9 opaque & transluc5t sub/ances by _! absorption ( sol> light1 b t ! sun's rays d n s5sibly alt] ! temp]ature ( p]fectly transp>5t bodies ?r\gh :i* !y pass4 ,z ! temp]ature ( ! pellucid planet>y space c be b little affect$ by ! passage ( ! sun's light & heat1 nei!r c x be s5sibly rais$ by ! heat n[ radiat$ f ! e>?4 ,d\btless ! radiation ( all ! bodies 9 ! univ]se ma9ta9s ! e!real m$ium at a high] temp]ature ?an x w\ld o!rwise h1 & mu/ ev5tually increase x1 b by a quantity s evanesc5t t x is h>dly possible to conceive a "t :5 a *ange w become p]ceptible4 ,! temp]ature ( space be+ s l[ z -#bci ,fahr5heit1 x becomes a matt] ( no small int]e/ to asc]ta9 :e!r ! e>? may n be ultimately r$uc$ by radiation to ! temp]ature ( ! surr\nd+ m$ium2 :at ! s\rces ( heat are2 & :e!r !y be suffici5t to comp5sate ! loss1 & to ma9ta9 ! e>? 9 a /ate fit = ! support ( animal & vegetable life 9 "t to come4 ,all obs]vations t h be5 made "u ! surface ( ! gr\nd concur 9 prov+ t !re is a /ratum at ! dep? ( f #dj to #ajj feet ?r\gh\t ! :ole e>? :]e ! temp]ature is inv>iable at all times & seasons1 & :i* diff]s b little f ! mean annual temp]ature ( ! c\ntry above4 ,accord+ to ,m4 ,b\ss+ault1 t /ratum at ! equator is at ! dep? ( little m ?an a foot 9 places %elt]$ f ! direct rays ( ! sun2 b 9 our climates x is at a mu* great] dep?4 ,9 ! c\rse ( m ?an half a c5tury ! temp]ature ( ! e>? at ! dep? ( #ij feet1 9 ! cell>s ( ! ,obs]vatory at ,p>is1 has nev] be5 above or bel[ #ec ( ,fahr5heit's !rmomet]1 :i* is only #b above ! mean annual temp]ature at ,p>is4 ,?is zone1 unaffect$ by ! sun's rays f above1 or by ! int]nal heat f bel[1 s]ves z an orig9 :5ce ! effects ( ! ext]nal heat are e/imat$ on "o side1 & ! int]nal temp]ature ( ! globe on ! o!r4 ,z e>ly z ! ye> #agdj ,m4 ,g5sanne discov]$ 9 ! lead-m9es ( ,giromagny1 9 ! ,vosges m\nta9s1 ?ree leagues f ,b=t1 t ! heat ( ! gr\nd increases ) ! dep? bel[ ! zone ( con/ant temp]ature4 ,a va/ numb] ( obs]vations h be5 made s9ce t "t1 9 ! m9es ( ,europe & ,am]ica1 by ,,mm4 ,saussure1 ,daubuisson1 ,humboldt1 ,cordi]1 ,fox1 ,rei*1 & o!rs1 :i* agree1 )\t an exception1 9 prov+ t ! temp]ature ( ! e>? becomes high] 9 desc5d+ t[>ds its c5tre4 ,! greate/ dep? t has be5 atta9$ is 9 ! silv]-m9e ( ,guanaxato1 9 ,mexico1 :]e ,m4 de ,humboldt f\nd a temp]ature ( #ih at ! dep? ( #bhe fa?oms1 ! mean annual temp]ature ( ! c\ntry be+ only #fa4 ,next to t is ! ,dalcoa? copp]-m9e1 9 ,cornwall1 :]e ,mr4 ,fox's !rmomet] /ood at #fh 9 a hole 9 ! rock at ! dep? ( #bcj fa?oms1 & at #hb 9 wat] at ! dep? ( #bdj fa?oms1 ! mean annual temp]ature at ! surface be+ ab\t #ej4 ,b x is ne$less to multiply examples1 all ( :i* concur 9 %[+ t !re is a v great diff]5ce betwe5 ! temp]ature 9 ! int]ior ( ! e>? & at its surface4 ,mr4 ,fox's obs]vations on ! temp]ature ( spr+s :i* rise at pr(\nd dep?s 9 m9es af=d ! /ronge/ te/imony4 ,he f\nd consid]able /reams fl[+ into "s ( ! ,corni% m9es at ! temp]ature ( #hj or #ij1 :i* is ab\t #cj or #dj above t ( ! surface1 & also asc]ta9$ t ne>ly #b1jjj1jjj gallons ( wat] are daily pump$ f ! bottom ( ! ,poldice m9e1 :i* is #agf fa?oms deep at #ij or #ajj4 ,z ?is is high] ?an ! w>m? ( ! human body1 ,mr4 ,fox ju/ly obs]ves t x am\nts to a pro( t ! increas$ temp]ature _c proce$ f ! p]sons ( ! workm5 employ$ 9 ! m9es4 ,nei!r c ! w>m? ( m9es be attribut$ to ! cond5sation ( ! curr5ts ( air :i* v5tilate !m4 ,mr4 ,fox1 ^: op9ion is ( high au?ority 9 ^! matt]s1 /ates t1 ev5 9 ! deepe/ m9es1 ! cond5sation ( ! air w\ld n raise ! temp]ature m ?an #e or #f2 & t1 if ! heat c\ld be attribut$ to ?is cause1 ! seasons w\ld s5sibly affect ! temp]ature ( m9es1 :i* x appe>s !y d n :]e ! dep? is great4 ,besides1 ! ,corni% m9es are g5]ally v5tilat$ by num]\s %afts op5+ into ! gall]ies f ! surface or f a high] level4 ,! air circulates freely 9 ^!1 desc5d+ 9 "s %afts & asc5d+ 9 o!rs4 ,9 all cases ,mr4 ,fox f\nd t ! upw>d curr5ts are ( a high] temp]ature ?an ! desc5d+ curr5ts2 s mu* s1 t 9 w9t] ! moi/ure is (t5 froz5 9 ! latt] to a consid]able dep?2 ! circulation ( air1 !re=e1 t5ds to cool ! m9e in/ead ( increas+ ! heat4 ,mr4 ,fox has also remov$ ! objections aris+ f ! comp>atively l[ temp]ature ( ! wat] 9 ! %afts ( ab&on$ m9es1 by %[+ t obs]vations 9 !m1 f a v>iety ( circum/ances :i* he enum]ates1 are too discordant to furni% any conclusion z to ! actual heat ( ! e>?4 ,! high temp]ature ( m9es might be attribut$ to ! effects ( ! fires1 c&les1 & gunp[d] us$ by ! m9]s1 did n a simil> increase obta9 9 deep wells1 & 9 bor+s to great dep?s 9 se>* ( wat]1 :]e no su* causes ( di/urbance occur4 ,9 a well dug ) a view to discov] salt 9 ! canton ( ,b]ne1 & long des]t$1 ,m4 de ,saussure _h ! mo/ complete evid5ce ( increas+ heat4 ,! same has be5 confirm$ by ! temp]ature ( _m wells1 bo? 9 ,france & ,engl&1 especially by ! ,artesian wells1 s nam$ f a peculi> me?od ( rais+ wat] fir/ resort$ to 9 ,artois1 & s9ce become v g5]al4 ,an ,artesian well consi/s ( a %aft a few in*es 9 diamet]1 bor$ into ! e>? till a spr+ is f\nd4 ,to prev5t ! wat] be+ c>ri$ (f by ! adjac5t /rata1 a tube is let d[n :i* exactly fills ! bore f top to bottom1 9 :i* ! wat] rises pure to ! surface4 ,x is cle> ! wat] c\ld n rise unless x _h previ\sly desc5d$ f high gr\nd ?r\gh ! int]ior ( ! e>? to ! bottom ( ! well4 ,x p>takes ( ! temp]ature ( ! /rata ?r\gh :i* x passes1 & 9 e in/ance has be5 w>m] 9 proportion to ! dep? ( ! well2 b x is evid5t t ! law ( increase _c be obta9$ 9 ?is mann]4 ,p]haps ! mo/ satisfactory exp]im5ts on record are ^? made by ,,mm4 ,augu/e de la ,rive & ,f4 ,m>cet dur+ ! ye> #ahcc1 9 a bor+ = wat] ab\t a league f ,g5eva1 at a place #cah feet above ! level ( ! lake4 ,! dep? ( ! bore 0 #gbg feet1 & ! diamet] only betwe5 f\r & five in*es4 ,no spr+ 0 ev] f\nd2 b ! %aft fill$ ) mud1 f ! moi/ure ( ! gr\nd mix+ ) ! e>? displac$ 9 bor+1 :i* 0 peculi>ly fav\rable = ! exp]im5ts1 z ! temp]ature at ea* dep? may be consid]$ to be t ( ! p>ticul> /ratum4 ,9 ?is case1 :]e none ( ! ord9>y causes ( di/urbance c\ld exi/1 & :]e e precaution 0 employ$ by sci5tific & exp]i5c$ obs]v]s1 ! temp]ature 0 f\nd to increase regul>ly & uni=mly ) ! dep? at ! rate ( ab\t #a ( ,fahr5heit = e #eb feet4 ,pr(essor ,rei* ( ,freyb]g has f\nd t ! mean ( a great numb] ( obs]vations bo? 9 m9es & wells is #a ( ,fahr5heit = e #ee feet ( dep?2 & f ,m4 ,arago's obs]vations 9 ! ,gr5elle ,artesian well at ,p>is1 ! increase is #a ( ,fahr5heit = e #de feet4 ,?\gh !re c be no d\bt z to ! increase ( temp]ature 9 p5etrat+ ! cru/ ( ! e>?1 !re is /ill mu* unc]ta9ty z to ! law ( increase1 :i* v>ies ) ! nature ( ! soil & o!r local circum/ances2 b1 on an av]age1 x has be5 e/imat$ at ! rate ( #a = e #ej or #fj feet1 :i* corresponds ) ! obs]vations ( ,,mm4 ,m>cet & ,de la ,rive4 ,9 consequ5ce ( ! rapid increase ( int]nal heat1 !rmal spr+s1 or su* z are indep5d5t ( volcanic action1 ris+ f a great dep?1 mu/ necess>ily be v r>e & ( a high temp]ature2 & x is actually f\nd t none are s l[ z #fh ( ,fahr5heit2 t ( ,*audes ,aigues1 9 ,auv]gne1 is ab\t #acf4 ,9 _m places w>m wat] f ,artesian wells w probably come into use = dome/ic purposes1 & x is ev5 n[ employ$ 9 manufactories ne> ,/utg>dt1 9 ,alsace1 c4 ,x is h>dly to be expect$ t at pres5t any in=mation ) reg>d to ! actual int]nal temp]ature ( ! e>? %\ld be obta9$ f t ( ! ocean1 on acc\nt ( ! mobility ( fluids1 by :i* ! cold] masses s9k d[nw>ds1 :ile ^? t are w>m] rise to ! surface4 ,nev]!less1 x may be /at$ t ! temp]ature ( ! sea decreases ) ! dep? betwe5 ! tropics2 :ile1 on ! contr>y1 all our nor!rn navigators f\nd t ! temp]ature increases ) ! dep? 9 ! pol> seas4 ,! *ange takes place ab\t ! #gj? p>allel ( latitude4 ,"s ages h5ce1 h[ev]1 x may be kn[n :e!r ! e>? has arriv$ at a p]man5t /ate z to heat1 by comp>+ secul> obs]vations ( ! temp]ature ( ! ocean if made at a great di/ance f ! l&4 ,%\ld ! e>?'s temp]ature increase at ! rate ( #a = e #ej feet1 x is cle> t at ! dep? ( #bjj miles ! h>de/ sub/ances mu/ be 9 a /ate ( fusion1 & our globe mu/ 9 t case ei!r be encompass$ by a /ratum ( melt$ lava at t dep?1 or x mu/ be a ball ( liquid fire #gfjj miles 9 diamet]1 enclos$ 9 a ?9 coat+ ( solid matt]2 = #bjj miles are no?+ :5 comp>$ ) ! size ( ! e>?4 ,no d\bt ! =m ( ! e>?1 z det]m9$ by ! p5dulum & arcs ( ! m]idian1 z well z by ! motions ( ! moon1 indicates orig9al fluidity & subsequ5t consolidation & r$uction ( temp]ature by radiation2 b :e!r ! law ( increas+ temp]ature is uni=m at /ill great] dep?s ?an ^? already atta9$ by man1 x is impossible to say4 ,at all ev5ts1 int]nal fluidity is n inconsi/5t ) ! pres5t /ate ( ! e>?'s surface1 s9ce e>?y matt] is z bad a conductor ( heat z lava1 :i* (t5 reta9s its heat at a v little dep? = ye>s aft] its surface is cool4 ,:atev] ! radiation ( ! e>? might h be5 9 =m] times1 c]ta9 x is t x goes on v sl[ly 9 our days2 = ,m4 ,f\ri] has comput$ t ! c5tral heat is decreas+ f radiation by only ab\t ! #a_/cjjjj? "p ( a degree 9 a c5tury4 ,if s1 !re c be no d\bt t x w ultimately be dissipat$2 b z f> z reg>ds animal & vegetable life1 x is ( v little consequ5ce :e!r ! c5tre ( our planet be liquid fire or ice1 s9ce its condition 9 ei!r case c\ld h no s5sible effect on ! climate at its surface4 ,! int]nal fire does n ev5 imp>t heat en\gh to melt ! sn[ at ! poles1 ?\gh ne>] to ! c5tre ?an any o!r "p ( ! globe4 ,! imm5se ext5t ( active volcanic fire is "o ( ! causes ( heat :i* mu/ n be ov]look$4 ,! range ( ! ,&es f ,*ile to ! nor? ( ,mexico1 probably f ,cape ,horn to ,behr+ ,/raits1 is "o va/ di/rict ( igne\s action1 includ+ ! ,c>ibbean & ! ,we/ ,indian ,isl&s on "o h&2 & /ret*+ q across ! ,pacific ,ocean1 ?r\gh ! ,polynesian ,ar*ipelago1 ! ,new ,hebrides1 ! ,georgian & ,fri5dly ,isl&s1 on ! o!r4 ,ano!r *a9 beg9s ) ! ,aleutian ,isl&s1 ext5ds to ,kamts*atka1 & f !nce passes ?r\gh ! ,kurile1 ,japanese1 & ,philipp9e ,isl&s1 to ! ,moluccas1 :5ce x spreads ) t]rific viol5ce ?r\gh ! ,indian ,ar*ipelago1 ev5 to ! ,bay ( ,b5gal4 ,volcanic action may aga9 be foll[$ f ! entrance ( ! ,p]sian ,gulf to ,madagasc>1 ,b\rbon1 ! ,can>ies1 & ,azores4 ,!nce a cont9u\s igne\s region ext5ds ?r\gh ab\t #ajjj geographical miles to ! ,caspian ,sea1 includ+ ! ,m$it]ranean1 & ext5d+ nor? & s\? betwe5 ! #ce? & #dj? p>allels ( latitude2 & 9 c5tral ,asia a volcanic region occupies #bejj squ>e geographical miles4 ,! volcanic fires are develop$ 9 ,icel& 9 trem5d\s =ce2 & ! ant>ctic l& discov]$ by ,sir ,james ,ross is an igne\s =mation ( ! bolde/ /ructure1 :]e a volcano 9 high activity rises #ab1jjj feet above ! p]petual ice ( ^! pol> des]ts1 & )9 #ai-a_/b ( ! s\? pole4 ,?r\gh\t ?is va/ portion ( ! _w ! subt]rane\s fire is (t5 int5sely active1 produc+ su* viol5t e>?quakes & eruptions t _! effects1 accumulat$ dur+ millions ( ye>s1 may acc\nt = _m ( ! great geological *anges ( igne\s orig9 t h already tak5 place 9 ! e>?1 & may occasion o!rs n less rem>kable1 %\ld "t--t ess5tial elem5t 9 ! vicissitudes ( ! globe--be grant$1 & _! en]gy la/4 ,sir ,*>les ,lyell1 :o has %[n ! p[] ( exi/+ causes ) great +5uity1 e/imates t on an av]age tw5ty eruptions take place annually 9 diff]5t p>ts ( ! _w2 & _m mu/ occur or h happ5$1 ev5 on ! mo/ ext5sive & awful scale1 among p equally incapable ( e/imat+ _! effects & ( record+ !m4 ,we %\ld nev] h kn[n ! ext5t ( ! fe>ful eruption :i* took place 9 ! isl& ( ,sumbawa1 9 #ahae1 b = ! accid5t ( ,sir ,/am=d ,raffles hav+ be5 gov]nor ( ,java at ! "t4 ,x began on ! #e? ( ,april1 & did n entirely cease till ,july4 ,! gr\nd 0 %ak5 ?r\gh an area ( #ajjj miles 9 circumf]5ce2 ! tremors 7 felt 9 ,java1 ! ,moluccas1 a great "p ( ,celebes1 ,sumatra1 & ,borneo4 ,! detonations 7 he>d 9 ,sumatra1 at ! di/ance ( #igj geographical miles 9 a /raight l9e2 & at ,t]nate1 #gbj miles 9 ! opposite direction4 ,! mo/ dreadful :irlw9ds c>ri$ m5 & cattle into ! air2 & ) ! exception ( #bf p]sons1 ! :ole population ( ! isl& p]i%$ to ! am\nt ( #ab1jjj4 ,a%es 7 c>ri$ #cjj miles to ,java 9 su* quantities t ! d>kness dur+ ! day 0 m pr(\nd ?an ev] _h be5 witness$ 9 ! mo/ obscure night4 ,! face ( ! c\ntry 0 *ang$ by ! /reams ( lava1 & by ! upheav+ & s9k+ ( ! soil4 ,! t[n ( ,tomboro 0 subm]g$1 & wat] /ood to ! dep? ( #ah feet 9 places :i* _h be5 dry l&4 ,%ips gr\nd$ :]e !y _h previ\sly an*or$1 & o!rs c\ld h>dly p5etrate ! mass ( c9d]s :i* float$ on ! surface ( ! sea = sev]al miles to ! dep? ( two feet4 ,a cata/rophe simil> to ?is1 ?\gh ( less magnitude1 took place 9 ! isl& ( ,bali 9 #ahjh1 :i* 0 n he>d ( 9 ,europe till ye>s aft]w>ds4 ,! eruption ( ,cosegu9a 9 ! ,bay ( ,fonseca1 :i* began on ! #ai? ( ,janu>y1 #ahce1 & la/$ _m days1 0 ev5 m dreadful & ext5sive 9 its effects ?an t ( ,sumbawa4 ,! a%es dur+ ?is eruption 7 c>ri$ by ! upp] curr5t ( ! atmosph]e z f> nor? z ,*iassa1 :i* is upw>ds ( #djj leagues to ! w9dw>d ( t volcano4 ,_m volcanoes suppos$ to be ext9ct h all at once bur/ out ) inconceivable viol5ce4 ,witness ,vesuvius1 on hi/orical record2 & ! volcano 9 ! isl& ( ,/4 ,v9c5t 9 our own days1 ^: crat] 0 l9$ ) l>ge trees1 & :i* _h n be5 active 9 ! memory ( man4 ,va/ tracts are ( volcanic orig9 :]e volcanoes h ceas$ to exi/ = ages4 ,:5ce x may be inf]r$ t 9 "s places ! subt]rane\s fires are 9 ! highe/ /ate ( activity1 9 "s !y are in]t1 & 9 o!rs !y appe> to be ext9ct4 ,yet !re are few c\ntries t are n subject to e>?quakes ( great] or less int5sity2 ! tremors are propagat$ l a sonor\s undulation to su* di/ances t x is impossible to say 9 :at po9t !y orig9ate4 ,9 "s rec5t in/ances _! p[] mu/ h be5 trem5d\s4 ,9 ,s\? ,am]ica1 s lately z #ahbb1 an area ( #ajj1jjj squ>e miles1 :i* is equal 9 ext5t to ! half ( ,france1 0 rais$ sev]al feet above its pres5t level--a mo/ able acc\nt ( :i* is giv5 9 ! #8,transactions ( ! ,geological ,society1' by an e/eem$ fri5d ( ! au?or's1 ! late ,mrs4 ,graham1 :o 0 pres5t dur+ ! :ole "t ( t =midable e>?quake1 :i* recurr$ at %ort int]vals = m ?an two mon?s1 & :o possess$ tal5ts to appreciate1 & _h opportunities ( obs]v+1 its effects "u ! mo/ fav\rable circum/ances at ,valp>aiso1 & = miles along ! coa/ :]e x 0 mo/ int5se4 ,a consid]able elevation ( ! l& has aga9 tak5 place along ! coa/ ( ,*ile1 9 consequ5ce ( ! viol5t e>?quake :i* happ5$ on ! #bj? ( ,febru>y1 #ahce4 ,9 #ahai a ridge ( l& /ret*+ = #ej miles across ! delta ( ! ,indus1 #af feet broad1 0 rais$ #aj feet above ! pla94 ,! read] is ref]r$ to ,sir ,*>les ,lyell's excell5t #8,pr9ciples ( ,geology1' already m5tion$1 = mo/ int]e/+ details ( ! ph5om5a & ext5sive effects ( volcanoes & e>?quakes1 too num]\s to f9d a place "h4 ,x may h[ev] be m5tion$ t innum]able e>?quakes are f "t to "t %ak+ ! solid cru/ ( ! globe1 & c>ry+ de/ruction to di/ant regions1 progressively ?\gh sl[ly accompli%+ ! great "w ( *ange4 ,a mo/ disa/r\s in/ance took place on ! #ae? ( ,decemb]1 #aheg1 9 ! ,neapolitan prov9ces ( ,la ,basilicata & ,pr9cipato ,cit]iore1 :]e ! de/ruction 0 ext5sive & t]rible2 ! numb] ( victims1 accord+ to ! (ficial acc\nts1 be+ return$ at upw>ds ( t5 ?\s&4 ,^! t]rible eng9es ( ru91 fitful & unc]ta9 z !y may seem1 mu/1 l all durable ph5om5a1 h a law :i* may 9 "t be discov]$ by long-cont9u$ & accurate obs]vations4 ,! %ell ( volcanic fire t girds ! globe at a small dep? bel[ our feet has be5 attribut$ to diff]5t causes4 ,by "s x is suppos$ to orig9ate 9 an ocean ( inc&esc5t matt]1 /ill exi/+ 9 ! c5tral abyss ( ! e>?4 ,"s conceive x to be sup]ficial1 & due to *emical action1 9 /rata at no v great dep? :5 comp>$ ) ! size ( ! globe4 ,! m s z matt] on a mo/ ext5sive scale is pass+ f old into new comb9ations1 :i*1 if rapidly effect$1 are capable ( produc+ ! mo/ int5se heat4 ,accord+ to o!rs1 electricity1 :i* is s univ]sally diffus$ 9 all its =ms ?r\gh\t ! e>?1 if n ! imm$iate cause ( ! volcanic ph5om5a1 at lea/ det]m9es ! *emical aff9ities t produce !m4 ,x is cle> t a subject s involv$ 9 my/]y mu/ give rise to mu* speculation1 9 :i* e hypo!sis is att5d$ ) difficulties t obs]vation alone c remove4 ,b ! views ( ,mr4 ,babbage & ,sir ,john ,h]s*el on ! g5]al cause ( volcanic action1 & ! *anges 9 ! equilibrium ( ! int]nal heat ( ! globe1 accord m ) ! laws ( me*anics & radiant heat ?an any t h be5 propos$4 ,! !ory ( ^! di/+ui%$ philosoph]s1 =m$ indep5d5tly ( ea* o!r1 is equally consi/5t ) obs]v$ ph5om5a1 :e!r ! e>? be a solid cru/ encompass+ a nucleus ( liquid lava1 or t !re is m]ely a va/ res]voir or /ratum ( melt$ matt] at a mod]ate dep? bel[ ! sup]ficial cru/4 ,! au?or is indebt$ to ! k9dness ( ,sir ,*>les ,lyell = ! p]usal ( a mo/ int]e/+ lett] f ,sir ,john ,h]s*el1 9 :i* he /ates 8 views on ! subject4 ,suppos+ t ! globe is m]ely a solid cru/1 re/+ ^u fluid or semi-fluid matt]1 :e!r ext5d+ to ! c5tre or n1 ! transf] ( pressure f "o "p ( its surface to ano!r by ! degradation ( exi/+ cont95ts1 & ! =mation ( new ones1 w\ld be suffici5t to subv]t ! equilibrium ( heat 9 ! int]ior1 & occasion volcanic eruptions4 ,=1 s9ce ! int]nal heat ( ! e>? is transmitt$ outw>ds by radiation1 an accession ( new matt] on any "p ( ! surface1 l an addition ( clo?+1 by keep+ x 91 w\ld raise ! temp]ature ( ! /rata bel[1 & 9 ! c\rse ( ages w\ld ev5 r$uce ^? at a great dep? to a /ate ( fusion4 ,"s ( ! sub/ances might be conv]t$ into gases2 & %\ld ! accumulation ( new matt] take place at ! bottom ( ! sea1 z is g5]ally ! case1 ?is lava w\ld be mix$ ) wat] 9 a /ate ( ignition 9 consequ5ce ( ! enorm\s pressure ( ! ocean1 & ( ! newly sup]impos$ matt] :i* w\ld prev5t x f exp&+ into /eam4 ,n[ ,sir ,*>les ,lyell has %[n1 ) 8 usual tal5t1 t ! quantity ( matt] c>ri$ d[n by riv]s f ! surface ( ! cont95ts is comp>atively trifl+1 & t ! great transf] to ! bottom ( ! ocean is produc$ at ! coa/-l9e by ! action ( ! sea2 h5ce1 says ,sir ,john ,h]s*el1 8! greate/ accumulation ( local pressure is 9 ! c5tral area ( ! deep sea1 :ile ! greate/ local relief takes place along ! abrad$ coa/-l9es4 ,"h !n %\ld occur ! *ief volcanic v5ts40 ,z ! cru/ ( ! e>? is mu* weak] on ! coa/s ?an else:]e1 x is m easily ruptur$1 &1 z ,mr4 ,babbage obs]ves1 imm5se r5ts might be produc$ !re by its contraction 9 cool+ d[n aft] be+ depriv$ ( a portion ( its orig9al ?ickness4 ,! pressure on ! bottom ( ! ocean w\ld =ce a column ( lava mix$ ) ignit$ wat] & gas to rise ?r\gh an op5+ ?us =m$1 &1 says ,sir ,john ,h]s*el1 8:5 ! column atta9s su* a height t ! ignit$ wat] c become /eam1 ! jo9t specific gravity ( ! column is sudd5ly dim9i%$1 & up comes a jet ( mix$ /eam & lava1 till s mu* has escap$ t ! matt] deposit$ at ! bottom ( ! ocean takes a fre% be>+1 :5 ! evacuation ceases & ! crack becomes seal$ up40 ,?is !ory p]fectly accords ) ! ph5om5a ( nature1 s9ce !re are v few active volcanoes at a di/ance f ! sea1 & ! exceptions t d occur are g5]ally ne> lakes1 or !y are connect$ ) volcanoes on ! m>itime coa/s4 ,_m break out ev5 9 ! bottom ( ! ocean1 probably ow+ to "s ( ! supports ( ! sup]ficial cru/ giv+ way1 s t ! /eam & lava are =c$ up ?r\gh ! fissures4 ,f9ally1 ,mr4 ,babbage obs]ves t1 89 consequ5ce ( *anges cont9ually go+ on1 by ! de/ruction ( =e/s1 ! fill+ up ( seas1 ! we>+ d[n ( elevat$ l&s1 ! heat radiat$ f ! e>?'s surface v>ies consid]ably at diff]5t p]iods4 ,9 consequ5ce ( ?is v>iation1 & also 9 consequ5ce ( ! cov]+ up ( ! bottom ( ! sea by ! detritus ( ! l&1 ! surfaces ( equal temp]ature )9 ! e>? are cont9ually *ang+ _! =m1 & expos+ ?ick b$s ne> ! ext]ior to alt]ations ( temp]ature4 ,! expansion & contraction ( ^! /rata may =m r5ts & ve9s1 produce e>?quakes1 det]m9e volcanic eruptions1 elevate cont95ts1 &1 possibly1 raise m\nta9 *a9s40 ,! num]\s v5ts = ! int]nal heat =m$ by volcanoes1 hot spr+s1 & ! emission ( /eam1 s frequ5t 9 volcanic regions1 no d\bt ma9ta9 ! tranquillity ( ! int]ior fluid mass1 :i* seems to be p]fectly in]t unless :5 put 9 motion by unequal pressure4 ,b1 to :atev] cause ! increas+ heat ( ! e>? & ! subt]ranean fires may ultimately be ref]r$1 x is c]ta9 t1 except 9 "s local in/ances1 !y h no s5sible effect on ! temp]ature ( its surface4 ,x may !re=e be conclud$ t ! heat ( ! e>?1 above ! zone ( uni=m temp]ature1 is entirely ow+ to ! sun4 ,! p[] ( ! sol> rays dep5ds mu* ^u ! mann] 9 :i* !y fall1 z we readily p]ceive f ! diff]5t climates on our globe4 ,al?\gh ! sun is ab\t ?ree millions ( miles ne>] to ! e>? 9 w9t] ?an 9 summ]1 8 rays /rike ! atmosph]e 9 ! nor!rn hemisph]e s obliquely t x absorbs a mu* great] quantity ( heat ?an :5 !y are m direct 7,n4 #bag74 ,inde$ x is s great t1 :5 ! sun has an altitude ( #cj1 "o half ( 8 heat is absorb$ by ! atmosph]e1 & x increases v rapidly z he s9ks t[>ds ! horizon4 ,h[ev]1 t heat is n lo/3 x is mo/ b5eficial to ! e>?1 be+ really ! heat :i* supplies ! greate/ "p ( t :i* is radiat$ into space dur+ ! abs5ce ( ! sun4 ,pr(essor ,dove has %[n1 by tak+ at all seasons ! mean ( ! temp]atures ( po9ts on ! e>?'s surface diametrically opposite to ea* o!r1 t ! av]age temp]ature ( ! :ole e>?'s surface 9 ,june1 :5 we are f>!/ f ! sun1 consid]ably exce$s t 9 ,decemb]1 :5 we are ne>e/ to him1 ow+ to ! excess ( wat] 9 ! s\!rn hemisph]e1 & t ( l& 9 ! nor!rn1 :i* gives a g5]al insul> climate to ! =m]1 & a cont95tal climate to ! latt]4 ,! obs]vations ( ! nor? pol> navigators1 & ^? ( ,sir ,john ,h]s*el at ! ,cape ( ,good ,hope1 %[ t ! direct heat+ influ5ce ( ! sol> rays is greate/ at ! equator1 & t x dim9i%es gradually z ! latitude increases4 ,at ! equator ! maximum is #dh-c_/d1 :ile 9 ,europe x has nev] exce$$ #bi-a_/b4 ,m4 ,p\illet has e/imat$ ) s+ul> +5uity1 f a s]ies ( obs]vations made by himself1 t ! :ole quantity ( heat :i* ! e>? receives annually f ! sun is su* z w\ld be suffici5t to melt a /ratum ( ice cov]+ ! :ole globe #df feet deep4 ,"p ( ?is heat is radiat$ back into space2 b by f> ! great] "p desc5ds into ! e>? dur+ ! summ]1 t[>ds ! zone ( uni=m temp]ature1 :5ce x returns to ! surface 9 ! c\rse ( ! w9t]1 & temp]s ! cold ( ! gr\nd & ! atmosph]e 9 its passage to ! e!real regions1 :]e x is lo/1 or r :]e x comb9es ) ! radiation f ! o!r bodies ( ! univ]se 9 ma9ta9+ ! temp]ature ( space4 ,! sun's p[] be+ greate/ betwe5 ! tropics1 ! heat s9ks deep] !re ?an else:]e1 & ! dep? gradually dim9i%es t[>ds ! poles2 b ! heat is also transmitt$ lat]ally f ! w>m] to ! cold] /rata nor? & s\? ( ! equator1 & aids 9 temp]+ ! sev]ity ( ! pol> regions4 ,! mean heat ( ! e>?1 above ! /ratum ( con/ant temp]ature1 is det]m9$ f t ( spr+s2 &1 if ! spr+ be on elevat$ gr\nd1 ! temp]ature is r$uc$ by computation to :at x w\ld be at ! level ( ! sea1 assum+ t ! heat ( ! soil v>ies accord+ to ! same law z ! heat ( ! atmosph]e1 :i* is ab\t #a ( ,fahr5heit's !rmomet] = e #cccg feet4 ,f a comp>ison ( ! temp]ature ( num]\s spr+s ) t ( ! air1 ,sir ,david ,brew/] concludes t !re is a p>ticul> l9e pass+ ne>ly ?r\gh ,b]l91 at :i* ! temp]ature ( spr+s & t ( ! atmosph]e co9cide2 t 9 approa*+ ! arctic circle ! temp]ature ( spr+s is always high] ?an t ( ! air1 :ile1 proce$+ t[>ds ! equator1 x is l[]4 ,s9ce ! w>m? ( ! sup]ficial /rata ( ! e>? decreases f ! equator to ! poles1 !re are _m places 9 bo? hemisph]es :]e ! gr\nd has ! same mean temp]ature4 ,if l9es 7 drawn ?r\gh all ^? po9ts 9 ! upp] /rata ( ! globe :i* h ! same mean annual temp]ature1 !y w\ld be ne>ly p>allel to ! equator betwe5 ! tropics1 & w\ld become m & m irregul> & s9u\s t[>ds ! poles4 ,^! are call$ isogeo!rmal l9es4 ,a v>iety ( local circum/ances di/urb _! p>allelism1 ev5 betwe5 ! tropics4 ,! temp]ature ( ! gr\nd at ! equator is l[] on ! coa/s & isl&s ?an 9 ! int]ior ( cont95ts2 ! w>me/ "p is 9 ! int]ior ( ,africa2 b x is obvi\sly affect$ by ! nature ( ! soil1 especially if x be volcanic4 ,mu* has be5 done to asc]ta9 ! mann] 9 :i* heat is di/ribut$ ov] ! surface ( our planet1 & ! v>iations ( climate1 :i*1 9 a g5]al view1 mean e *ange ( ! atmosph]e1 su* z ( temp]ature1 humidity1 v>iations ( b>ometric pressure1 purity ( air1 ! s]5ity ( ! heav5s1 ! effects ( w9ds1 & electric t5sion4 ,temp]ature dep5ds ^u ! prop]ty :i* all bodies possess1 m or less1 ( p]petually absorb+ & emitt+ or radiat+ heat4 ,:5 ! int]*ange is equal1 ! temp]ature ( a body rema9s ! same2 b1 :5 ! radiation exce$s ! absorption1 x becomes cold]1 & vice v]s4 ,9 ord] to det]m9e ! di/ribution ( heat ov] ! surface ( ! e>?1 x is necess>y to f9d a /&>d by :i* ! temp]ature 9 diff]5t latitudes may be comp>$4 ,= t purpose x is requisite to asc]ta91 by exp]im5t1 ! mean temp]ature ( ! day1 ( ! mon?1 & ( ! ye>1 at z _m places z possible ?r\gh\t ! e>?4 ,! annual av]age temp]ature may be f\nd by add+ ! mean temp]atures ( all ! mon?s 9 ! ye>1 & divid+ ! sum by twelve4 ,! av]age ( t5 or fifte5 ye>s w give x approximately2 =1 al?\gh ! temp]ature 9 any place maybe subject to v great v>iations1 yet x nev] deviates m ?an a few degrees f its mean /ate1 :i* consequ5tly (f]s a good /&>d ( comp>ison4 ,z a /&>d1 h[ev]1 mu* great] accuracy is requir$4 ,if climate dep5d$ solely ^u ! heat ( ! sun1 all places hav+ ! same latitude w\ld h ! same mean annual temp]ature4 ,! motion ( ! sun 9 ! ecliptic1 inde$1 occasions p]petual v>iations 9 ! l5g? ( ! day1 & 9 ! direction ( ! rays ) reg>d to ! e>?2 yet1 z ! cause is p]iodic1 ! mean annual temp]ature f ! sun's motion alone mu/ be con/ant 9 ea* p>allel ( latitude2 = x is evid5t t ! accumulation ( heat 9 ! long days ( summ]1 :i* is b little dim9i%$ by radiation dur+ ! %ort nights1 is balanc$ by ! small quantity ( heat receiv$ dur+ ! %ort days 9 w9t]1 & its radiation 9 ! long1 fro/y1 & cle> nights4 ,9 fact1 if ! globe 7 ev]y:]e on a level ) ! surface ( ! sea1 & ( uni=m sub/ance1 s z to absorb & radiate heat equally1 ! mean heat ( ! sun w\ld be regul>ly di/ribut$ ov] its surface 9 zones ( equal annual temp]ature p>allel to ! equator1 f :i* x w\ld decrease to ea* pole z ! squ>e ( ! cos9e ( ! latitude2 & its quantity w\ld only dep5d ^u ! altitude ( ! sun & atmosph]ic curr5ts4 ,! di/ribution ( heat1 h[ev]1 9 ! same p>allel1 is v irregul> 9 all latitudes except betwe5 ! tropics1 :]e ! iso!rmal l9es1 or ! l9es pass+ ?r\gh places ( equal mean annual temp]ature1 are m ne>ly p>allel to ! equator4 ,! causes ( di/urbance are v num]\s2 b su* z h ! greate/ influ5ce1 accord+ to ,m4 de ,humboldt1 to :om we are indebt$ = ! great] "p ( :at is kn[n on ! subject1 are ! elevation ( ! cont95ts1 ! di/ribution ( l& & wat] ov] ! surface ( ! globe expos+ diff]5t absorb+ & radiat+ p[]s2 ! v>iations 9 ! surface ( ! l&1 z =e/s1 s&y des]ts1 v]dant pla9s1 rocks1 c42 m\nta9-*a9s cov]$ ) masses ( sn[1 :i* dim9i% ! temp]ature2 ! rev]b]ation ( ! sun's rays 9 ! valleys1 :i* increases x2 & ! int]*ange ( curr5ts1 bo? ( air & wat]1 :i* mitigates ! rig\r ( climates2 ! w>m curr5ts f ! equator s(t5+ ! sev]ity ( ! pol> fro/s1 & ! cold curr5ts f ! poles temp]+ ! int5se heat ( ! equatorial regions4 ,to ^! may be add$ cultivation1 ?\gh its influ5ce ext5ds ov] b a small portion ( ! globe1 only a f\r? "p ( ! l& be+ inhabit$4 ,temp]ature decreases ) ! height above ! level ( ! sea1 z well z ) ! latitude4 ,! air 9 ! high] regions ( ! atmosph]e is mu* cool] ?an t bel[1 because ! w>m air exp&s z x rises1 by :i* its capacity = heat is increas$1 a great proportion becomes lat5t or absorb$1 & less ( x s5sible4 ,a portion ( air at ! surface ( ! e>? ^: temp]ature is #gj ( ,fahr5heit1 if c>ri$ to ! height ( two miles & a half1 w\ld exp& s mu* t its temp]ature w\ld be r$uc$ #ej2 & 9 ! e!real regions ! temp]ature is #bci bel[ ! z]o po9t ( ,fahr5heit4 ,! height at :i* sn[ lies p]petually decreases f ! equator to ! poles1 & is high] 9 summ] ?an 9 w9t]2 b x v>ies f _m circum/ances4 ,sn[ r>ely falls :5 ! cold is int5se & ! atmosph]e dry4 ,ext5sive =e/s produce moi/ure by _! evaporation2 & high table-l&s1 on ! contr>y1 dry & w>m ! air1 because ! air at great elevations is too r>e to absorb mu* ( ! sun's heat4 ,9 ! ,cordill]as ( ! ,&es1 pla9s ( only tw5ty-five squ>e leagues f _! ext5t raise ! temp]ature z mu* z #c or #d above :at is f\nd at ! same altitude on ! rapid declivity ( a m\nta91 consequ5tly ! l9e ( p]petual sn[ v>ies accord+ z "o or o!r ( ^! causes prevails4 ,aspect 9 g5]al has also a great influ5ce2 yet ! l9e ( p]petual sn[ is mu* high] on ! nor!rn ?an on ! s\!rn side ( ! ,himalaya1 p>tly because ! air is ne>ly depriv$ ( its moi/ure by precipitation be=e x arrives at ! nor!rn side ( ! m\nta9s4 ,on ! :ole1 x appe>s t ! mean height betwe5 ! tropics at :i* ! sn[ lies p]petually is ab\t #ae1bjg feet above ! level ( ! sea2 :]eas sn[ does n cov] ! gr\nd cont9ually at ! level ( ! ocean till ne> ! nor? pole4 ,9 ! s\!rn hemisph]e1 h[ev]1 ! cold is great] ?an 9 ! nor!rn4 ,9 ,s&wi* ,l&1 betwe5 ! #ed? & #eh? degrees ( latitude1 p]petual sn[ & ice ext5d to ! sea-level2 & 9 ! isl& ( ,s4 ,georgia1 9 ! #ecrd degree ( s\? latitude1 :i* corresponds ) ! latitude ( ! c5tral c\nties ( ,engl&1 p]petual sn[ desc5ds ev5 to ! level ( ! ocean4 ,x has be5 %[n t ?is excess ( cold 9 ! s\!rn hemisph]e _c be attribut$ to ! w9t] be+ long] ?an ours by #g-c_/d days4 ,x is probably ow+ to ! op5 sea surr\nd+ ! s\? pole1 :i* p]mits ! iceb]gs to desc5d to a l[] latitude by #aj ?an !y d 9 ! nor!rn hemisph]e1 on acc\nt ( ! num]\s ob/ructions oppos$ to !m by ! isl&s & cont95ts ab\t ! nor? pole4 ,iceb]gs f ! ,arctic seas seldom float f>!r to ! s\? ?an ! ,azores2 :]eas ^? t come f ! s\? pole desc5d to z l[ a latitude z t ( ! ,cape ( ,good ,hope4 ,! influ5ce ( m\nta9-*a9s does n :olly dep5d ^u ! l9e ( p]petual congelation4 ,!y attract & cond5se ! vap\rs float+ 9 ! air1 & s5d !m d[n 9 torr5ts ( ra94 ,!y radiate heat into ! atmosph]e at a l[] elevation1 & increase ! temp]ature ( ! valleys by ! reflection ( ! sun's rays1 & by ! %elt] !y af=d aga9/ prevail+ w9ds4 ,b1 on ! contr>y1 "o ( ! mo/ g5]al & p[]ful causes ( cold aris+ f ! vic9ity ( m\nta9s is ! freez+ curr5ts ( w9d :i* ru% f _! l(ty peaks along ! rapid declivities1 *ill+ ! surr\nd+ valleys3 su* is ! cutt+ nor? w9d call$ ! bise 9 ,switz]l&4 ,next to elevation1 ! diff]5ce 9 ! radiat+ & absorb+ p[]s ( ! sea & l& has ! greate/ influ5ce 9 di/urb+ ! regul> di/ribution ( heat4 ,! ext5t ( ! dry l& is n above ! f\r? "p ( t ( ! ocean2 s t ! g5]al temp]ature ( ! atmosph]e1 reg>d$ z ! result ( ! p>tial temp]atures ( ! :ole surface ( ! globe1 is mo/ p[]fully modifi$ by ! sea4 ,besides1 ! ocean acts m uni=mly on ! atmosph]e ?an ! div]sifi$ surface ( ! solid mass does1 bo? by ! equality ( its curvature & its homog5eity4 ,9 opaque sub/ances ! accumulation ( heat is conf9$ to ! /ratum ne>e/ ! surface4 ,! seas become less heat$ at _! surface ?an ! l&1 because ! sol> rays1 be=e be+ ext+ui%$1 p5etrate ! transp>5t liquid to a great] dep? & 9 great] numb]s ?an 9 ! opaque masses4 ,on ! o!r h&1 wat] has a consid]able radiat+ p[]1 :i*1 toge!r ) evaporation1 w\ld r$uce ! surface ( ! ocean to a v l[ temp]ature1 if ! cold p>ticles did n s9k to ! bottom on acc\nt ( _! sup]ior d5sity4 ,! seas pres]ve a consid]able portion ( ! heat !y receive 9 summ]1 & f _! saltness d n freeze s soon z fre% wat]4 ,s t1 9 consequ5ce ( all ^! circum/ances1 ! ocean is n subject to su* v>iations ( heat z ! l&1 &1 by imp>t+ its temp]ature to ! w9ds & by its curr5ts1 x dim9i%es ! rig\r ( climate on ! coa/s & 9 ! isl&s1 :i* are nev] subject to su* extremes ( heat & cold z are exp]i5c$ 9 ! int]ior ( cont95ts1 ?\gh !y are liable to fogs & ra9 f ! evaporation ( ! adjac5t seas4 ,on ea* side ( ! equator to ! #dh? degree ( latitude1 ! surface ( ! ocean is 9 g5]al w>m] ?an ! air above x4 ,! mean ( ! diff]5ce ( ! temp]ature at noon & midnight is ab\t #acg1 ! greate/ deviation nev] exce$+ f #jcf to #baf1 :i* is mu* cool] ?an ! air ov] ! l&4 ,on l& ! temp]ature dep5ds ^u ! nature ( ! soil & its products1 its habitual moi/ure or dryness4 ,f ! ea/]n extremity ( ! ,sah>a des]t q across ,africa1 ! soil is almo/ entirely b>r5 s&2 & ! ,sah>a des]t itself ext5ds ov] an area ( #aid1jjj squ>e leagues1 equal to twice ! area ( ! ,m$it]ranean ,sea1 & raises ! temp]ature ( ! air by radiation f #ij to #ajj1 :i* mu/ h a mo/ ext5sive influ5ce4 ,on ! contr>y1 vegetation cools ! air by evaporation & ! app>5t radiation ( cold f ! leaves ( plants1 because !y absorb m caloric ?an !y give out4 ,! gram9if]\s pla9s ( ,s\? ,am]ica cov] an ext5t t5 times great] ?an ,france1 occupy+ no less ?an ab\t #ej1jjj squ>e leagues1 :i* is m ?an ! :ole *a9 ( ! ,&es1 & all ! scatt]$ m\nta9-gr\ps ( ,brazil4 ,^!1 toge!r ) ! pla9s ( ,nor? ,am]ica & ! /eppes ( ,europe & ,asia1 mu/ h an ext5sive cool+ effect on ! atmosph]e if x be consid]$ t 9 calm & s]5e nights !y cause ! !rmomet] to desc5d #ab or #ad1 & t 9 ! mead[s & hea?s 9 ,engl& ! absorption ( heat by ! grass is suffici5t to cause ! temp]ature to s9k to ! po9t ( congelation dur+ ! night = t5 mon?s 9 ! ye>4 ,=e/s cool ! air also by %ad+ ! gr\nd f ! rays ( ! sun1 & by evaporation f ! b\ghs4 ,hales f\nd t ! leaves ( a s+le plant ( helian?us ?ree feet high expos$ ne>ly =ty feet ( surface2 &1 if x be consid]$ t ! woody regions ( ! riv] ,amazons1 & ! high] "p ( ! ,or9oco1 occupy an area ( #bfj1jjj squ>e leagues1 "s idea may be =m$ ( ! torr5ts ( vap\r :i* rise f ! leaves ( ! =e/s all ov] ! globe4 ,h[ev]1 ! frigorific effects ( _! evaporation are c\nt]act$ 9 "s measure by ! p]fect calm :i* reigns 9 ! tropical wild]nesses4 ,! innum]able riv]s1 lakes1 pools1 & m>%es int]sp]s$ ?r\gh ! cont95ts absorb caloric1 & cool ! air by evaporation2 b1 on acc\nt ( ! *ill$ & d5se p>ticles s9k+ to ! bottom1 deep wat] dim9i%es ! cold ( w9t]1 s long z ice is n =m$4 ,9 consequ5ce ( ! diff]5ce 9 ! radiat+ & absorb+ p[]s ( ! sea & l&1 _! configuration greatly modifies ! di/ribution ( heat ov] ! surface ( ! globe4 ,"u ! equator only "o-six? "p ( ! circumf]5ce is l&2 & ! sup]ficial ext5t ( l& 9 ! nor!rn & s\!rn hemisph]es is 9 ! proportion ( ?ree to "o4 ,! effect ( ?is unequal division is great] 9 ! temp]ate ?an 9 ! torrid zones1 = ! area ( l& 9 ! nor!rn temp]ate zone is to t 9 ! s\!rn z ?irte5 to "o1 :]eas ! proportion ( l& betwe5 ! equator & ea* tropic is z five to f\r4 ,x is a curi\s fact1 notic$ by ,mr4 ,g>dn]1 t only "o tw5ty-sev5? "p ( ! l& ( ! globe has l& diametrically opposite to x4 ,?is disproportionate arrangem5t ( ! solid "p ( ! globe has a p[]ful influ5ce on ! temp]ature ( ! s\!rn hemisph]e4 ,b1 besides ^! great] modifications1 ! p59sulas1 promontories1 & capes1 runn+ out into ! ocean1 toge!r ) bays & int]nal seas1 all affect temp]ature4 ,to ^! may be add$ ! position ( cont95tal masses ) reg>d to ! c>d9al po9ts4 ,all ^! div]sities ( l& & wat] influ5ce temp]ature by ! ag5cy ( ! w9ds4 ,on ?is acc\nt ! temp]ature is l[] on ! ea/]n coa/s bo? ( ! ,new & ,old ,_w ?an on ! we/]n2 =1 consid]+ ,europe z an isl&1 ! g5]al temp]ature is mild 9 proportion z ! aspect is op5 to ! ,atlantic ,ocean1 ! sup]ficial temp]ature ( :i*1 z f> nor? z ! #de? & #ej? degrees ( latitude1 does n fall bel[ #dh or #ea ( ,fahr5heit1 ev5 9 ! middle ( w9t]4 ,on ! contr>y1 ! cold ( ,russia arises f its exposure to ! nor!rn & ea/]n w9ds4 ,b ! ,european "p ( t empire has a less rigor\s climate ?an ! ,asiatic1 because x does n ext5d to s high a latitude4 ,! int]position ( ! atmosph]e modifies all ! effects ( ! sun's heat4 ,! e>? communicates its temp]ature s sl[ly1 t ,m4 ,arago has occasionally f\nd z mu* z f #ad to #ah ( diff]5ce betwe5 ! heat ( ! soil & t ( ! air two or ?ree in*es above x4 ,! circum/ances :i* h be5 enum]at$1 & _m m1 concur 9 di/urb+ ! regul> di/ribution ( heat ov] ! globe1 & occasion numb]less local irregul>ities4 ,nev]!less ! mean annual temp]ature becomes gradually l[] f ! equator to ! poles4 ,b ! dim9ution ( mean heat is mo/ rapid betwe5 ! #dj? & #de? degrees ( latitude bo? 9 ,europe & ,am]ica1 :i* accords p]fectly ) !ory2 :5ce x appe>s t ! v>iation 9 ! squ>e ( ! cos9e ( ! latitude 7,n4 #abg71 :i* expresses ! law ( ! *ange ( temp]ature1 is a maximum t[>ds ! #de? degree ( latitude4 ,! mean annual temp]ature "u ! equator 9 ,am]ica is ab\t #ha-a_/b ( ,fahr5heit3 9 ,africa x is said to be ne>ly #hc4 ,! diff]5ce probably arises f ! w9ds ( ,sib]ia & ,canada1 ^: *illy influ5ce is s5sibly felt 9 ,asia & ,am]ica1 ev5 )9 #ah ( ! equator4 ,! iso!rmal l9es are ne>ly p>allel to ! equator1 till ab\t ! #bbnd degree ( latitude on ea* side ( x1 :]e !y beg9 to lose _! p>allelism1 & cont9ue to d s m & m z ! latitude augm5ts4 ,) reg>d to ! nor!rn hemisph]e1 ! iso!rmal l9e ( #ei ( ,fahr5heit passes betwe5 ,rome & ,flor5ce 9 latitude #dc2 & ne> ,raleigh 9 ,nor? ,c>ol9a1 latitude #cf3 t ( #ej ( equal annual temp]ature runs ?r\gh ! ,ne!rl&s1 latitude #ea2 & ne> ,bo/on 9 ! ,unit$ ,/ates1 latitude #db-a_/b3 t ( #da passes ne> ,/ockholm1 latitude #ei-a_/b2 & ,/4 ,george's ,bay1 ,newf\ndl&1 latitude #dh3 & la/ly1 ! l9e ( #cb1 ! freez+ po9t ( wat]1 passes betwe5 ,ulea 9 ,lapl&1 latitude #ff1 & ,table ,bay1 on ! coa/ ( ,labrador1 latitude #ed4 ,?us x appe>s t ! iso!rmal l9es1 :i* are ne>ly p>allel to ! equator = ab\t #bb1 aft]w>ds deviate m & m4 ,f obs]vations made dur+ ! num]\s voyages 9 ! ,arctic ,seas1 x is f\nd t ! iso!rmal l9es ( ,europe & ,am]ica entirely sep>ate 9 ! high latitudes1 & surr\nd two poles ( maximum cold3 "o1 9 #gi ,n4 lat4 & #abj ,e4 long41 has a mean temp]ature ( #b ,fahr5heit2 & ! o!r1 ^: temp]ature 0 det]m9$ by ,sir ,david ,brew/] to be #c-a_/b ,fahr5heit1 f ! obs]vations ( ,sir ,edw>d ,p>ry is ne> ,melville ,isl&4 ,! pole ( ! e>?'s rotation1 ^: mean temp]ature is probably n bel[ #ae ,fahr5heit1 is ne>ly midway betwe5 ! two2 & ! l9e :i* jo9s ^! po9ts ( maximum cold is almo/ co9cid5t ) t diamet] ( ! pol> bas9 :i* bisects x1 & passes ?r\gh its two great outlets into ! ,pacific & ,atlantic ,oceans1 a mo/ rem>kable feature1 & /rongly indicative ( ! abs5ce ( l&1 & ( ! preval5ce ( a mat]ially mild] climate 9 ! pol> ,ocean1 probably n "u #ae ,fahr5heit4#ab ,x is believ$ t two correspond+ poles ( maximum cold exi/ 9 ! s\!rn hemisph]e1 ?\gh obs]vations are want+ to trace ! c\rse ( ! s\!rn iso!rmal l9es ) ! same accuracy z ! nor!rn4 ,! iso!rmal l9es1 or su* z pass ?r\gh places :]e ! mean annual temp]ature ( ! air is ! same1 d n always co9cide ) ! isogeo!rmal l9es1 :i* are ^? pass+ ?r\gh places :]e ! mean temp]ature ( ! gr\nd is ! same4 ,sir ,david ,brew/]1 9 discuss+ ?is subject1 f9ds t ! isogeo!rmal l9es are always p>allel to ! iso!rmal l9es2 consequ5tly ! same g5]al =mula w s]ve to det]m9e bo?1 s9ce ! diff]5ce is a con/ant quantity obta9$ by obs]vation1 & dep5d+ ^u ! di/ance ( ! place f ! neutral iso!rmal l9e4 ,^! results are confirm$ by ! obs]vations ( ,m4 ,kupff] ( ,kasan dur+ 8 excursions to ! nor?1 :i* %[ t ! ,european & ! ,am]ican portions ( ! isogeo!rmal l9e ( #cb ( ,fahr5heit actually sep>ate1 & g r\nd ! two poles ( maximum cold4 ,?is travell] rem>k$1 also1 t ! temp]ature bo? ( ! air & ( ! soil decreases mo/ rapidly t[>ds ! #de? degree ( latitude4 ,x is evid5t t places may h ! same mean annual temp]ature1 & yet diff] mat]ially 9 climate4 ,9 "o1 ! w9t]s may be mild & ! summ]s cool2 :]eas ano!r may exp]i5ce ! extremes ( heat & cold4 ,l9es pass+ ?r\gh places hav+ ! same mean summ] or w9t] temp]ature are nei!r p>allel to ! iso!rmal1 ! geo!rmal l9es1 nor to "o ano!r1 & !y diff] /ill m f ! p>allels ( latitude4 ,9 ,europe1 ! latitude ( two places :i* h ! same annual heat nev] diff]s m ?an #h or #i2 :]eas ! diff]5ce 9 ! latitude ( ^? hav+ ! same mean w9t] temp]ature is sometimes z mu* z #ah or #ai4 ,at ,kasan1 9 ! int]ior ( ,russia1 9 latitude #eedh1 ne>ly ! same ) t ( ,ed9burgh1 ! mean annual temp]ature is ab\t #cgf2 at ,ed9burgh x is #dghd4 ,at ,kasan ! mean summ] temp]ature is #fdhd1 & t ( w9t] #bab2 :]eas at ,ed9burgh ! mean summ] temp]ature is #ehbh1 & t ( w9t] #chff4 ,:5ce x appe>s t ! diff]5ce ( w9t] temp]ature is mu* great] ?an t ( summ]4 ,at ,quebec ! summ]s are z w>m z ^? 9 ,p>is1 & grapes sometimes rip5 9 ! op5 air3 :]eas ! w9t]s are z sev]e z 9 ,pet]sburgh2 ! sn[ lies five feet deep = sev]al mon?s1 :eel c>riages _c be us$1 ! ice is too h>d = skat+1 travell+ is p]=m$ 9 sl$ges1 & frequ5tly on ! ice ( ! riv] ,/4 ,lawr5ce4 ,! cold at ,melville ,isl& on ! #ae? ( ,janu>y1 #ahbj1 accord+ to ,sir ,edw>d ,p>ry1 0 #ee bel[ ! z]o ( ,fahr5heit's !rmomet]2 & :5 ,dr4 ,kane 0 on ! nor!rn coa/ ( ,gre5l& x 0 #gj bel[ t po9t2 yet ! summ] heat dur+ ! day 9 ^! high latitudes is insupportable4 ,obs]vations t5d to prove t all ! climates ( ! e>? are /able1 & t _! vicissitudes are only p]iods or oscillations ( m or less ext5t1 :i* vani% 9 ! mean annual temp]ature ( a suffici5t numb] ( ye>s4 ,?is con/ancy ( ! mean annual temp]ature ( ! diff]5t places on ! surface ( ! globe %[s t ! same quantity ( heat :i* is annually receiv$ by ! e>? is annually radiat$ into space2 & t w\ld be ! case ev5 if ! quantity ( heat emitt$ by ! sun %\ld v>y ) 8 spots1 =1 if m 7 receiv$1 m w\ld be radiat$4 ,nev]!less1 a v>iety ( causes may di/urb ! climate ( a place2 cultivation may make x w>m]2 b x is at ! exp5se ( "s o!r place1 :i* becomes cold] 9 ! same proportion4 ,!re may be a succession ( cold summ]s & mild w9t]s1 b 9 "s o!r c\ntry ! contr>y takes place to effect ! comp5sation2 w9d1 ra91 sn[1 fog1 & ! o!r meteoric ph5om5a1 are ! m9i/]s employ$ to accompli% ! *anges4 ,! di/ribution ( heat may v>y ) a v>iety ( circum/ances2 b ! absolute quantity lo/ & ga9$ by ! :ole e>? 9 ! c\rse ( a ye>1 if n inv>iably ! same1 is at lea/ p]iodical4 ,,section ,,xxvi4 ,influ5ce ( ,temp]ature on ,vegetation--,vegetation v>ies ) ! ,latitude & ,height above ! ,sea--,geographical ,di/ribution ( ,l& ,plants--,di/ribution ( ,m>9e ,plants--,corall9es1 ,%ell-fi%1 ,reptiles1 ,insects1 ,birds1 & ,quadrup$s--,v>ieties ( ,mank9d1 yet id5tity ( ,species4 ,,! gradual decrease ( temp]ature 9 ! air & 9 ! e>?1 f ! equator to ! poles1 is cle>ly indicat$ by its influ5ce on vegetation4 ,9 ! valleys ( ! torrid zone1 :]e ! mean annual temp]ature is v high1 & :]e !re is abundance ( light & moi/ure1 nature adorns ! soil ) all ! luxuriance ( p]petual summ]4 ,! palm1 ! bombax ceiba1 & a v>iety ( magnific5t trees1 t[] to ! height ( #aej or #bjj feet above ! banana1 ! bamboo1 ! arboresc5t f]n1 & numb]less o!r tropical productions1 s int]lac$ by creep+ & p>asitical plants1 z (t5 to pres5t an imp5etrable b>ri]4 ,b ! ri*ness ( vegetation gradually dim9i%es ) ! temp]ature2 ! spl5d\r ( ! tropical =e/ is succe$$ by ! regions ( ! v9e & olive2 ^! aga9 yield to ! v]dant mead[s ( m temp]ate climes2 !n foll[ ! bir* & ! p9e1 :i* probably owe _! exi/5ce 9 v high latitudes m to ! w>m? ( ! soil ?an to t ( ! air4 ,b ev5 ^! endur+ plants become dw>fi% %rubs1 till a v]dant c>pet ( mosses & li*5s1 enamell$ ) fl[]s1 exhibits ! la/ sign ( vegetable life dur+ ! %ort b f]vid summ]s at ! pol> regions4 ,su* is ! effect ( cold & dim9i%$ light on ! vegetable k+dom1 t ! numb] ( species gr[+ "u ! equator & 9 ! nor!rn latitudes ( #de & #fh are 9 ! proportion ( ! numb]s #ab1 #d1 & #a4 ,not)/&+ ! rem>kable diff]5ce betwe5 a tropical & pol> flora1 light & moi/ure seem to be almo/ ! only requisites = vegetation1 s9ce nei!r heat1 cold1 nor ev5 comp>ative d>kness1 absolutely de/roy ! f]tility ( nature4 ,9 salt pla9s & s&y des]ts alone hopeless b>r5ness prevails4 ,plants gr[ on ! bord]s ( hot spr+s3 !y =m ! oases :]ev] moi/ure exi/s among ! burn+ s&s ( ,africa2 !y are f\nd 9 cav]ns almo/ void ( light1 ?\gh g5]ally blan*$ & feeble4 ,! ocean teems ) vegetation4 ,! sn[ itself n only produces a r$ li*51 discov]$ by ,saussure 9 ! froz5 declivities ( ! ,alps1 f\nd 9 abundance by ! au?or cross+ ! ,col de ,bonhomme f ,savoy to ,pi$mont1 & by ! pol> navigators 9 ! ,arctic regions1 b x af=ds %elt] to ! productions ( ^! inhospitable climes aga9/ ! pi]c+ w9ds t sweep ov] fields ( ev]la/+ ice4 ,^? undaunt$ m>9]s n>rate t "u ?is cold def5ce plants spr+ up1 dissolve ! sn[ a few in*es r\nd1 & ! "p above1 be+ aga9 quickly froz5 into a transp>5t %eet ( ice1 admits ! sun's rays1 :i* w>m & *]i% ! plants 9 ?is natural ho?\se1 till ! return+ summ] r5d]s su* protection unnecess>y4 ,! *emical action ( light is1 h[ev]1 absolutely requisite = ! gr[? ( plants :i* d]ive _! pr9cipal n\ri%m5t f ! atmosph]e4 ,!y consume ! c>bonic acid gas1 nitrog51 aque\s vap\r1 & ammonia x conta9s2 b x is ! *emical ag5cy ( light t enables !m to absorb1 decompose1 & consolidate ^! sub/ances into wood1 leaves1 fl[]s1 & fruit4 ,! atmosph]e w\ld soon be depriv$ ( ^! elem5ts ( vegetable life 7 !y n p]petually suppli$ by ! animal creation2 :ile1 9 return1 plants decompose ! moi/ure !y imbibe1 &1 hav+ assimilat$ ! c>bonic acid gas1 !y exhale oxyg5 = ! ma9t5ance ( ! animat$ creation1 & ?us pres]ve a j equilibrium4 ,h5ce x is ! comb9$ & p[]ful influ5ces ( ! :ole sol> beams t give su* brilliancy to ! tropical =e/s1 :ile1 ) _! decreas+ en]gy 9 ! high] latitudes1 vegetation becomes less vigor\s4 ,on t acc\nt x is va9 to expect t ! fruit & fl[]s rais$ 9 our ho?\ses c ev] h ! flav\r1 p]fume1 or col\r+ equal to t :i* !y acquire f ! vivid light ( _! native skies4 ,by f> ! great] numb] ( ! kn[n species ( plants are indig5\s 9 equ9octial ,am]ica2 ,europe conta9s ab\t half ! numb]2 ,asia1 ) its isl&s1 some:at less ?an ,europe2 ,au/ralia1 ) ! isl&s 9 ! ,pacific1 /ill less2 & 9 ,africa !re are few] kn[n vegetable productions ?an 9 any "p ( ! globe ( equal ext5t1 = t ri* & luxuriant region discov]$ by ,dr4 ,liv+/one has yet to be explor$ botanically4 ,v few social plants1 su* z grasses & hea?s t cov] l>ge tracts ( l&1 are to be f\nd betwe5 ! tropics1 except on ! sea-coa/s & elevat$ pla9s4 ,"s exceptions to ?is1 h[ev]1 are to be met ) 9 ! jungles ( ! ,deccan1 c4 ,9 ! equatorial regions1 :]e ! heat is always great1 ! di/ribution ( plants dep5ds ^u ! mean annual temp]ature2 :]eas 9 temp]ate zones ! di/ribution is regulat$ 9 "s degree by ! summ] heat4 ,"s plants require a g5tle heat ( long cont9uance1 o!rs fl\ri% mo/ :]e ! extremes ( heat & cold are great]4 ,! range ( :eat is v great2 x may be cultivat$ z f> nor? z ! #fj? degree ( latitude2 b 9 ! torrid zone x w seldom =m an e> bel[ an elevation ( #dejj feet above ! level ( ! sea f exub]ance ( vegetation2 nor w x rip5 g5]ally above ! height ( #ab1jjj feet2 9 ,tibet x rip5s at a /ill great] elevation4 ,colonel ,sykes /ates t 9 ! ,deccan :eat ?rives z l[ z #ahjj feet above ! sea4 ,! be/ w9es are produc$ betwe5 ! #cj? & #de? degrees ( nor? latitude4 ,) reg>d to ! vegetable k+dom1 elevation is equival5t to latitude z f> z temp]ature is conc]n$4 ,9 asc5d+ ! m\nta9s ( ! torrid zone1 ! ri*ness ( ! tropical vegetation dim9i%es ) ! height2 a succession ( plants simil> to1 ?\gh n id5tical )1 ^? f\nd 9 latitudes ( correspond+ mean temp]ature takes place2 ! l(ty =e/s by degrees lose _! spl5d\r2 /unt$ %rubs succe$2 till at la/ ! progress ( ! li*5 is *eck$ by p]petual sn[4 ,on ! volcano ( ,t5]iffe !re are five successive zones1 ea* produc+ di/9ct families ( plants4 ,! fir/ is ! region ( v9es1 ! next t ( laurels2 ^! are foll[$ by ! region ( p9es1 ( ,ericas or hea?s1 ( grass2 ! :ole cov]+ ! declivity ( ! peak ?r\gh an ext5t ( #aa1bjj feet ( p]p5dicul> height4 ,ne> ! equator oaks fl\ri% at ! height ( #ibjj feet above ! sea2 &1 on ! l(ty range ( ! ,himalaya1 ! primula1 ! convall>ia1 & ! v]onica fl[]1 b n ! primrose1 ! lily ( ! valley1 or ! v]onica1 :i* adorn our mead[s2 =1 al?\gh ! h]b>ium collect$ by ,moorcr(t1 on 8 r\te f ,neetee to ,daba & ,g>tope 9 ,*9ese ,t>t>y1 at elevations z high or ev5 high] ?an ,mont ,blanc1 ab\nd 9 ,alp9e & ,european g5]a1 ! species are univ]sally diff]5t1 ) ! s+le exception ( ! ,rhodiola rosea1 :i* is id5tical ) ! species t blooms 9 ,scotl&4 ,x is n 9 ?is in/ance alone t simil>ity ( climate obta9s )\t id5tity ( productions2 ?r\gh\t ! :ole globe a c]ta9 analogy bo? ( /ructure & appe>ance is frequ5tly discov]$ betwe5 plants "u correspond+ circum/ances :i* are yet specifically diff]5t4 ,x is ev5 said t a diff]5ce ( #be ( latitude occasions a total *ange1 n only ( vegetable productions1 b ( organis$ be+s4 ,c]ta9 x is t ea* sep>ate region bo? ( l& & wat]1 f ! froz5 %ores ( ! pol> circles to ! burn+ regions ( ! torrid zone1 possesses a flora peculi>ly its own4 ,! :ole globe has be5 divid$ by physical geograph]s into v>i\s botanical di/ricts1 diff]+ almo/ entirely 9 _! specific vegetable productions1 ! limits ( :i* are mo/ decid$ :5 !y are sep>at$ by a wide expanse ( ocean1 m\nta9 *a9s1 s&y des]ts1 salt pla9s1 or int]nal seas4 ,a consid]able numb] ( plants are common to ! nor!rn regions ( ,asia1 ,europe1 & ,am]ica1 :]e ! cont95ts almo/ unite2 b1 9 approa*+ ! s\?1 ! floras ( ^! ?ree great divisions ( ! globe diff] m & m ev5 9 ! same p>allels ( latitude1 :i* %[s t temp]ature alone is n ! cause ( ! almo/ complete div]sity ( species t ev]y:]e prevails4 ,! floras ( ,*9a1 ,sib]ia1 ,t>t>y1 ( ! ,european di/rict includ+ c5tral ,europe & ! coa/ ( ! ,m$it]ranean1 & ! ,ori5tal region compris+ ! c\ntries r\nd ! ,black & ,caspian ,seas1 all diff] 9 specific "*4 ,only tw5ty-f\r species 7 f\nd by ,,mm4 ,humboldt & ,bonpl& 9 ,equ9octial ,am]ica id5tical ) ^? ( ! ,old ,_w2 & ,dr4 ,rob]t ,br[n n only f\nd t a peculi> vegetation exi/s 9 ,au/ralia betwe5 ! #ccrd & #ce? p>allels ( s\? latitude1 b t at ! ea/]n & we/]n extremities ( ^! p>allels n "o species is common to bo?1 & t c]ta9 g5]a also are almo/ entirely conf9$ to ^! spots4 ,! numb] ( species common to ,au/ralia & ,europe are only #aff out ( #dajj1 & probably "s ( ^! h be5 convey$ ?i!r by ! coloni/s2 b ! great] "p ( t cont95t is /ill unexplor$4 ,h[ev]1 ?is proportion exce$s :at has hi!rto be5 obs]v$ 9 s\!rn ,africa1 &1 f :at has be5 already /at$1 ! proportion ( ,european species 9 ,equ9octial ,am]ica is /ill less4 ,isl&s p>take ( ! vegetation ( ! ne>e/ cont95ts2 b1 :5 v remote f l&1 _! floras are altoge!r peculi>4 ,! ,aleutian ,isl&s1 ext5d+ betwe5 ,asia & ,am]ica1 p>take ( ! vegetation ( ! nor!rn p>ts ( bo? cont95ts1 & may h s]v$ z a *a9 ( communication4 ,9 ,madeira & ,t5]iffe1 ! plants ( ,portugal1 ,spa91 ! ,azores1 & ( ! nor!rn coa/ ( ,africa1 are f\nd2 & ! ,can>ies conta9 a great numb] ( plants belong+ to ! ,african coa/4 ,b ea* ( ^! isl&s possesses a flora t exi/s n[h]e else2 & ,/4 ,hel5a1 /&+ alone 9 ! mid/ ( ! ,atlantic ,ocean1 produces only two or ?ree species ( plants recognis$ z belong+ to any o!r "p ( ! _w4 ,x appe>s f ! inve/igations ( ,m4 de ,humboldt t betwe5 ! tropics ! plants1 su* z grasses & palms1 :i* h only "o se$-lobe1 are to ! tribe :i* h two se$-lobes1 l mo/ ( ! ,european species1 9 ! proportion ( "o to f\r2 9 ! temp]ate zones !y are z "o to six2 & 9 ! ,arctic regions1 :]e mosses & li*5s1 :i* =m ! l[e/ ord] ( ! vegetable creation1 ab\nd1 ! proportion is z "o to two4 ,annuals ) "o & two se$-lobes1 9 ! temp]ate zones1 am\nt to "o-six? ( ! :ole1 omitt+ ! cryptogamia 7,n4 #bah72 9 ! torrid zone !y sc>cely =m "o-tw5tie?1 & 9 ,lapl& "o-?irtie? "p4 ,9 approa*+ ! equator ! ligne\s exce$ ! numb] ( h]bace\s plants2 9 ,am]ica !re are #abj diff]5t species ( =e/ trees1 :]eas 9 ! same latitudes 9 ,europe only #cd are to be f\nd4 ,simil> laws regulate ! di/ribution ( m>9e plants4 ,gr\ps ( alg1 or m>9e plants1 affect p>ticul> temp]atures or zones ( latitude & diff]5t dep?s1 ?\gh "s few g5]a prevail ?r\gh\t ! ocean4 ,! pol> ,atlantic bas9 to ! #dj? degree ( nor? latitude pres5ts a well-def9$ vegetation4 ,! ,we/ ,india seas1 includ+ ! ,gulf ( ,mexico1 ! ea/]n coa/ ( ,s\? ,am]ica1 ! ,indian ,ocean & its gulfs1 ! %ores ( ,new ,holl&1 & ! neighb\r+ isl&s1 h ea* _! di/9ct species4 ,! ,m$it]ranean possesses a vegetation peculi> to itself1 ext5d+ to ! ,black ,sea2 & ! species ( m>9e plants on ! coa/ ( ,syria & 9 ! port ( ,alex&ria diff] almo/ entirely f ^? ( ,suez & ! ,r$ ,sea4 ,x is obs]v$ t %all[ seas h a diff]5t set ( plants f su* z are deep] & cold]2 &1 unlike t]re/rial vegetation1 ! alg are m num]\s 9 ! mean latitudes ?an ei!r t[>ds ! equator or ! poles4 ,!y v>y also ) ! dep?3 completely diff]5t k9ds affect diff]5t dep?s1 _! se$s be+ ( su* specific gravity z to rema9 & g]m9ate :]e ! p>5t plant grew4 ,! quantity ( alg 9 t accumulation kn[n z ! s>gassa or grassy sea is s great1 t ! e>ly navigators1 ,columbus & ,l]ius1 comp>$ x to ext5sively inundat$ mead[s3 x imp$$ _! %ips1 & al>m$ _! sailors4 ,x is 9 ! ,nor? ,atlantic1 a little to ! we/ ( ! m]idian ( ,fayal1 "o ( ! ,azores1 betwe5 ! #be? & #cf? p>allels ( latitude4 ,a small] bank lies betwe5 ! #bbnd & #bf? degrees ( nor? latitude1 ab\t #hj leagues we/ ( ! m]idian ( ! ,bahama ,isl&s4 ,^! masses *iefly consi/ ( "o or two species ( s>gassa1 ! mo/ ext5sive g5us ( ! ord] ,fucoide4 ,"s ( ! seawe$s gr[ to enorm\s l5g?s1 & all are highly col\r$1 ?\gh _m ( !m mu/ gr[ 9 deep wat]4 ,light1 h[ev]1 may n be ! only pr9ciple on :i* ! col\r ( vegetables dep5ds1 s9ce ,b>on ,humboldt met ) gre5 plants gr[+ 9 complete d>kness 9 "o ( ! m9es at ,freyb]g4 ,9 ! d>k & tranquil caves ( ! ocean1 on ! %ores alt]nately cov]$ & des]t$ by ! re/less waves1 on ! l(ty m\nta9 & ext5d$ pla91 9 ! *illy regions ( ! nor?1 & 9 ! g5ial w>m? ( ! s\?1 specific div]sity is a g5]al law ( ! vegetable k+dom1 :i* _c be acc\nt$ = by div]sity ( climate2 & yet ! simil>ity1 ?\gh n id5tity1 ( species is su*1 "u ! same iso!rmal l9es1 t if ! numb] ( species belong+ to "o ( ! great families ( plants be kn[n 9 any "p ( ! globe1 ! :ole numb] ( ! fl[]+ or m p]fect plants1 & also ! numb] ( species compos+ ! o!r vegetable families1 may be e/imat$ ) consid]able accuracy4 ,v>i\s op9ions h be5 =m$ on ! orig9al or primitive di/ribution ( plants ov] ! face ( ! globe2 b1 s9ce botanical geography has become a sci5ce1 ! ph5om5a obs]v$ h l$ to ! conclusion t vegetable creation mu/ h tak5 place 9 a numb] ( di/9ctly diff]5t c5tres1 z ! isl&s & cont95ts rose above ! ocean1 ea* ( :i* 0 ! orig9al seat ( a c]ta9 numb] ( peculi> species :i* at fir/ grew !re & n[h]e else4 ,hea?s are exclusively conf9$ to ! ,old ,_w2 & no indig5\s rose-tree has ev] be5 se5 9 ! ,new1 ! :ole s\!rn hemisph]e be+ de/itute ( t beautiful & fragrant plant4 ,b ?is is /ill m confirm$ by multitudes ( p>ticul> plants1 hav+ an entirely local & insulat$ exi/5ce1 gr[+ spontane\sly 9 "s p>ticul> spot1 & 9 no o!r place3 = example1 ! c$> ( ,lebanon1 :i* gr[s indig5\sly on t m\nta91 & 9 no o!r "p ( ! _w4 ,on ! o!r h&1 z !re c be no d\bt t _m races ( plants h be5 ext+ui%$1 ,sir ,john ,h]s*el ?9ks x possible t ^! solit>y in/ances may be ! la/ surviv+ remnants ( ! same gr\p univ]sally dissem9at$1 b 9 c\rse ( ext9ction1 or t p]haps two processes may be go+ on at ! same "t3--8,"s gr\ps may be spread+ f _! foci1 o!rs retreat+ to _! la/ holds40 ,! same laws obta9 9 ! di/ribution ( ! animal creation4 ,ev5 ! microscopic exi/5ces1 :i* seem to be ! mo/ widely spread1 h _! specific localities2 & ! zoophyte 7,n4 #bai71 occupy+ ! next l[e/ place 9 animat$ nature1 is widely scatt]$ ?r\gh ! seas ( ! torrid zone1 ea* species be+ conf9$ to ! di/rict & dep? be/ suit$ to its wants4 ,mollusks1 or ! animals ( %ells1 decrease 9 size & beauty ) _! di/ance f ! equator2 & n only ea* sea & e bas9 ( ! ocean1 b ea* dep?1 is inhabit$ by its peculi> tribe ( fi%4 ,inde$1 ,,mm4 ,p]on & ,le ,sueur ass]t t1 among ! _m ?\s&s ( m>9e animals :i* !y _h exam9$1 !re is n a s+le animal ( ! s\!rn regions :i* is n di/+ui%able by ess5tial *>act]s f ! analog\s species 9 ! nor!rn seas4 ,reptiles are n exempt f ! g5]al law4 ,! saurian 7,n4 #bbj7 tribes ( ! f\r qu>t]s ( ! globe diff] 9 species2 &1 al?\gh w>m c\ntries ab\nd 9 v5om\s snakes1 !y are specifically diff]5t 9 diff]5t localities1 & decrease bo? 9 numb]s & 9 ! virul5ce ( _! poison ) decrease ( temp]ature4 ,! disp]sion ( insects necess>ily foll[s t ( ! vegetables :i* supply _! food2 & 9 g5]al x is obs]v$ t ea* k9d ( plant is peopl$ by its peculi> inhabitants4 ,ea* species ( bird has its peculi> haunt1 not)/&+ ! locomotive p[]s ( ! w+$ tribes4 ,! emu is conf9$ to ,au/ralia1 ! condor to ! ,&es & _! declivities1 & ! be>d$ vulture or lemm]gey] to ! ,alps4 ,"s birds1 l ! common sp>r[1 h a wide range2 b ^? met ) 9 e c\ntry are few 9 numb]4 ,quadrup$s are di/ribut$ 9 ! same mann] :]ev] man has n int]f]$4 ,su* z are indig5\s 9 "o c\ntry are n ! same ) _! cong5]s 9 ano!r2 &1 ) ! exception ( "s k9d ( bats1 no mammif]\s animal is indig5\s 9 ! ,polynesian ,ar*ipelago1 nor 9 any ( ! isl&s on ! bord]s ( ! c5tral "p ( ! ,pacific4 ,9 review+ ! inf9ite v>iety ( organis$ be+s t p ! surface ( ! globe1 no?+ is m rem>kable ?an ! di/9ctions :i* *>act]ise ! diff]5t tribes ( mank9d1 f ! ebony sk9 ( ! torrid zone to ! fair & ruddy complexion ( ! ,sc&9avian--a diff]5ce :i* exi/$ 9 ! e>lie/ record$ times1 s9ce ! ,african is repres5t$ 9 ! sacr$ writ+s to h be5 z black z he is at ! pres5t day1 & ! mo/ anci5t ,egyptian pa9t+s confirm t tru?2 yet x appe>s1 f a comp>ison ( ! pr9cipal circum/ances relat+ to ! animal economy or physical "* ( ! v>i\s tribes ( mank9d1 t ! diff]5t races are id5tical 9 species4 ,_m attempts h be5 made to trace ! v>i\s tribes back to a common orig91 by collat+ ! num]\s languages :i* are or h be5 spok54 ,"s classes ( ^! h few or no words 9 common1 yet exhibit a rem>kable analogy 9 ! laws ( _! grammatical con/ruction4 ,! languages spok5 by ! native ,am]ican nations af=d examples ( ^!2 inde$1 ! ref9em5t 9 ! grammatical con/ruction ( ! tongues ( ! ,am]ican savages leads to ! belief t !y mu/ orig9ally h be5 spok5 by a mu* m civilis$ class ( mank9d4 ,"s tongues h little or no resemblance 9 /ructure1 ?\gh !y correspond ext5sively 9 _! vocabul>ies1 z ! ,syrian dialects4 ,9 all ^! cases x may be inf]r$ t ! nations speak+ ! languages 9 "q desc5d$ f ! same /ock2 b ! probability ( a common orig9 is mu* great] 9 ! ,indo-,european nations1 ^: languages1 su* z ! ,sanscrit1 ,greek1 ,lat91 ,g]man1 c41 h an aff9ity bo? 9 /ructure & correspond5ce ( vocables4 ,9 _m tongues n ! smalle/ resemblance c be trac$2 l5g? ( "t1 h[ev]1 may h oblit]at$ orig9al id5tity2 b s _m ages h pass$ be=e ! subject became a /udy1 & s _m languages h worn out ( use1 t x may be d\bt$ :e!r any satisfactory result w ev] be arriv$ at ) reg>d to ! orig9al spee* ( mank9d4 ,,section ,,xxvii4 ,t]re/rial ,heat--,radiation--,transmission--,mello ni's exp]im5ts--,heat 9 ,sol> ,spectrum--,pol>ization ( ,heat--,nature ( ,heat--,absorptions--,dew--,ra9--,combu/ ion--,expansion--,comp5sation ,p5dulum--,transmission ?r\gh ,cry/als--,propagation--,dynamic ,!ory ( ,heat--,me*anical equival5t ( ,heat--,lat5t ,heat is ! ,=ce ( ,expansion--,/eam--,"w p]=m$ by ,heat--,cons]vation ( ,=ce--,me*anical ,p[] 9 ! ,tides--,dynamical ,p[] ( ,light--,analogy betwe5 ,light1 ,heat1 & ,s\nd4 ,,t heat produc+ rays exi/ indep5d5tly ( ^? ( light is a matt] ( con/ant exp]i5ce 9 ! abundant emission ( !m f boil+ wat]4 ,!y d>t 9 div]g5t /raight l9es f flame & f ea* po9t 9 ! surfaces ( hot bodies1 9 ! same mann] z div]g+ rays ( light proce$ f e po9t ( ^? t are lum9\s4 ,accord+ to ! exp]im5ts ( ,sir ,john ,leslie1 radiation proce$s n only f ! surface ( sub/ances1 b also f ! p>ticles at a m9ute dep? bel[ x4 ,he f\nd t ! emission is mo/ abundant 9 a direction p]p5dicul> to ! radiat+ surface1 & t x is m rapid f a r\gh ?an f a poli%$ surface3 radiation1 h[ev]1 c only take place 9 air & 9 vacuo2 x is altoge!r imp]ceptible :5 ! hot body is enclos$ 9 a solid or liquid4 ,heat$ sub/ances1 :5 expos$ to ! op5 air1 cont9ue to radiate heat till !y become ne>ly ( ! temp]ature ( ! surr\nd+ m$ium4 ,! radiation is v rapid at fir/1 b dim9i%es accord+ to a kn[n law ) ! temp]ature ( ! heat$ body4 ,x appe>s1 also1 t ! radiat+ p[] ( a surface is inv]sely z its reflect+ p[]2 & bodies t are mo/ imp]meable to heat radiate lea/4 ,sub/ances1 h[ev]1 h an elective p[]1 only reflect+ heat ( a c]ta9 refrangibility4 ,mr4 ,grove gives pap]1 sn[1 & lime z in/ances1 :i*1 al?\gh all :ite1 radiate heat ( diff]5t refrangibilities1 :ile metals1 :atev] _! col\r may be1 radiate all k9ds alike4 ,rays ( heat1 :e!r !y proce$ f ! sun1 f flame1 or o!r t]re/rial s\rces1 lum9\s or non-lum9\s1 are in/antane\sly transmitt$ ?r\gh solid & liquid sub/ances1 !re be+ no appreciable diff]5ce 9 ! "t !y take to pass ?r\gh lay]s ( any nature or ?ickness :atev]4 ,!y pass also ) ! same facility :e!r ! m$ia be agitat$ or at re/2 & 9 ^! respects ! analogy betwe5 light & heat is p]fect4 ,radiant heat passes ?r\gh ! gases ) ! same facility z light2 b a rem>kable diff]5ce obta9s 9 ! transmission ( light & heat ?r\gh mo/ solid & liquid sub/ances1 ! same body be+ (t5 p]fectly p]meable to ! lum9\s1 & altoge!r imp]meable to ! calorific rays4 ,= example1 ?9 & p]fectly transp>5t plates ( alum & citric acid s5sibly transmit all ! rays ( light f an arg& lamp1 b /op eight or n9e t5?s ( ! concomitant heat2 :il/ a l>ge piece ( br[n rock-cry/al gives a free passage to ! radiant heat1 b int]cepts almo/ all ! light4 ,alum unit$ to gre5 glass is also capable ( transmitt+ ! brighte/ light1 b x gives n ! slighte/ indication ( heat2 :ile rock-salt cov]$ ?ickly ov] ) soot1 s z to be p]fectly opaque to light1 transmits a consid]able quantity ( heat4 ,m4 ,melloni has e/abli%$ ! g5]al law 9 uncry/alliz$ sub/ances su* z glass & liquids1 t ! prop]ty ( in/antane\sly transmitt+ heat is 9 proportion to _! refractive p[]s4 ,! law1 h[ev]1 is entirely at fault 9 bodies ( a cry/all9e texture4 ,c>bonate ( lead1 = in/ance1 :i* is col\rless1 & possesses a v high refractive p[] ) reg>d to light1 transmits less radiant heat ?an ,icel& sp> or rock-cry/al1 :i* are v inf]ior to x 9 ! ord] ( refrangibility2 :il/ rock-salt1 :i* has ! same transp>5cy & refractive p[] ) alum & citric acid1 transmits six or eight times z mu* heat4 ,?is rem>kable diff]5ce 9 ! transmissive p[] ( sub/ances hav+ ! same appe>ance is attribut$ by ,m4 ,melloni to _! cry/all9e =m1 & n to ! *emical composition ( _! molecules1 z ! foll[+ exp]im5ts prove4 ,a block ( common salt cut into plates entirely excludes calorific radiation2 yet1 :5 dissolv$ 9 wat]1 x increases ! transmissive p[] ( t liquid3 moreov]1 ! transmissive p[] ( wat] is increas$ 9 ne>ly ! same degree1 :e!r salt or alum be dissolv$ 9 x2 yet ^! two sub/ances transmit v diff]5t quantities ( heat 9 _! solid /ate4 ,not)/&+ ! influ5ce ( cry/allization on ! transmissive p[] ( bodies1 no relation has be5 trac$ betwe5 t p[] & ! cry/all9e =m4 ,! transmission ( radiant heat is analog\s to t ( light ?r\gh col\r$ m$ia4 ,:5 common :ite light passes ?r\gh a r$ liquid1 almo/ all ! m refrangible rays1 & a few ( ! r$1 are int]cept$ by ! fir/ lay] ( ! fluid2 few] are int]cept$ by ! second1 /ill less by ! ?ird1 & s on3 till at la/ ! losses become v small & inv>iable1 & ^? rays alone are transmitt$ :i* give ! r$ col\r to ! liquid4 ,9 a simil> mann]1 :5 plates ( ! same ?ickness ( any sub/ance1 su* z glass1 are expos$ to an arg& lamp1 a consid]able portion ( ! radiant heat is arre/$ by ! fir/ plate1 a less portion by ! second1 /ill less by ! ?ird1 & s on1 ! quantity ( lo/ heat decreas+ till at la/ ! loss becomes a con/ant quantity4 ,! transmission ( radiant heat ?r\gh a solid mass foll[s ! same law4 ,! losses are v consid]able on fir/ ent]+ x1 b !y rapidly dim9i% 9 proportion z ! heat p5etrates deep]1 & become con/ant at a c]ta9 dep?4 ,inde$1 ! only diff]5ce betwe5 ! transmission ( radiant heat ?r\gh a solid mass1 or ?r\gh ! same mass :5 cut into plates ( equal ?ickness1 arises f ! small quantity ( heat t is reflect$ at ! surface ( ! plates4 ,x is evid5t1 !re=e1 t ! heat gradually lo/ is n int]cept$ at ! surface1 b absorb$ 9 ! int]ior ( ! sub/ance1 & t heat :i* has pass$ ?r\gh "o /ratum ( air exp]i5ces a less absorption 9 ea* ( ! succe$+ /rata1 & may !re=e be propagat$ to a great] di/ance be=e x is ext+ui%$4 ,! exp]im5ts ( ,m4 de ,l>o*e %[ t glass1 h[ev] ?91 totally int]cepts ! obscure rays ( heat :5 !y fl[ f a body ^: temp]ature is l[] ?an t ( boil+ wat]2 t1 z ! temp]ature increases1 ! calorific rays are transmitt$ m & m abundantly2 &1 :5 ! body becomes highly lum9\s1 t !y p5etrate ! glass ) p]fect ease4 ,! extreme brilliancy ( ! sun is probably ! reason :y 8 heat1 :5 br\ght to a focus by a l5s1 is m int5se ?an any t has be5 produc$ artificially4 ,x is ow+ to ! same cause t glass scre5s1 :i* entirely exclude ! heat ( a common fire1 are p]meable by ! sol> heat4 ,! results obta9$ by ,m4 de ,l>o*e h be5 confirm$ by ! exp]im5ts ( ,m4 ,melloni on heat radiat$ f s\rces ( diff]5t temp]atures1 :5ce x appe>s t ! calorific rays pass less abundantly n only ?r\gh glass1 b ?r\gh rock-cry/al1 ,icel& sp>1 & o!r diaphan\s bodies1 bo? solid & liquid1 accord+ z ! temp]ature ( _! orig9 is dim9i%$1 & t !y are altoge!r int]cept$ :5 ! temp]ature is ab\t t ( boil+ wat]4 ,9 fact1 he has prov$ t ! heat emanat+ f ! sun or f a bright flame consi/s ( rays :i* diff] f ea* o!r z mu* z ! col\r$ rays d :i* con/itute :ite light4 ,?is expla9s ! reason ( ! loss ( heat z x p5etrates deep] & deep] into a solid mass1 or 9 pass+ ?r\gh a s]ies ( plates2 =1 ( ! diff]5t k9ds ( rays :i* d>t f a vivid flame1 all are successively ext+ui%$ by ! absorb+ nature ( ! sub/ance ?r\gh :i* !y pass1 till ^? homog5e\s rays alone rema9 :i* h ! greate/ facility 9 pass+ ?r\gh t p>ticul> sub/ance2 exactly z 9 a r$ liquid ! violet1 blue1 gre51 orange1 & yell[ rays are ext+ui%$1 & ! r$ are transmitt$4 ,m4 ,melloni employ$ f\r s\rces ( heat1 two ( :i* 7 lum9\s & two obscure2 namely1 an oil-lamp )\t a glass1 inc&esc5t plat9a1 copp] heat$ to #fif1 & a copp] vessel fill$ ) wat] at ! temp]ature ( #agh-a_/b ( ,fahr5heit4 ,rock-salt transmitt$ heat 9 ! proportion ( #ib rays out ( #ajj f ea* ( ^! s\rces2 b all o!r sub/ances p]vi\s to radiant heat1 :e!r solid or liquid1 transmitt$ m heat f s\rces ( high temp]ature ?an f su* z are l[4 ,= in/ance1 limpid & col\rless fluate ( lime transmitt$ 9 ! proportion ( #gh rays out ( #ajj f ! lamp1 #fi f ! plat9a1 #db f ! copp]1 & #cc f ! hot wat]2 :ile transp>5t rock-cry/al transmitt$ #ch rays 9 #ajj f ! lamp1 #bh f ! plat9a1 #f f ! copp]1 & #i f ! hot wat]4 ,pure ice transmitt$ only 9 ! proportion ( #f rays 9 ! #ajj f ! lamp1 & entirely exclud$ ^? f ! o!r ?ree s\rces4 ,out ( #ci diff]5t sub/ances1 #cd 7 p]vi\s to ! calorific rays f hot wat]1 #ad exclud$ ^? f ! hot copp]1 & #d did n transmit ^? f ! plat9um4 ,?us x appe>s t heat proce$+ f ^! f\r s\rces is ( diff]5t k9ds3 ?is diff]5ce 9 ! nature ( ! calorific rays is also prov$ by ano!r exp]im5t1 :i* w be m easily und]/ood f ! analogy ( light4 ,r$ light1 emanat+ f r$ glass1 w pass 9 abundance ?r\gh ano!r piece ( r$ glass1 b x w be absorb$ by gre5 glass2 gre5 rays w m readily pass ?r\gh a gre5 m$ium ?an ?r\gh "o ( any o!r col\r4 ,?is holds ) reg>d to all col\rs2 s 9 heat4 ,rays ( heat ( ! same int5sity1 :i* h pass$ ?r\gh diff]5t sub/ances1 are transmitt$ 9 diff]5t quantities by ! same piece ( alum1 & are sometimes /opp$ altoge!r2 %[+ t rays :i* emanate f diff]5t sub/ances possess diff]5t qualities4 ,x appe>s t a bright flame furni%es rays ( heat ( all k9ds1 9 ! same mann] z x gives light ( all col\rs2 &1 z col\r$ m$ia transmit "s col\r$ rays & absorb ! re/1 s bodies transmit "s rays ( heat & exclude ! o!rs4 ,rock-salt alone resembles col\rless transp>5t m$ia 9 transmitt+ all k9ds ( heat1 ev5 t ( ! h&1 j z !y transmit :ite light1 consi/+ ( rays ( all col\rs4 ,radiant heat is unequally refract$ by a prism ( rock-salt l light1 & ! rays ( heat ?us disp]s$ are f\nd to possess prop]ties analog\s to ! rays ( ! col\r$ spectrum4 ,! prop]ty ( transmitt+ ! calorific rays dim9i%es to a c]ta9 degree ) ! ?ickness ( ! body !y h to trav]se1 b n s mu* z might be expect$4 ,a piece ( v transp>5t alum transmitt$ ?ree or f\r times less radiant heat f ! flame ( a lamp ?an a piece ( ne>ly opaque qu>tz ab\t a hundr$ times z ?ick4 ,h[ev]1 ! influ5ce ( ?ickness ^u ! ph5om5a ( transmission increases ) ! decrease ( temp]ature 9 ! orig9 ( ! rays1 & becomes v great :5 t temp]ature is l[4 ,?is is a circum/ance intimately connect$ ) ! law e/abli%$ by ,m4 de ,l>o*e2 = ,m4 ,melloni obs]v$ t ! diff]5ce betwe5 ! quantities ( heat transmitt$ by ! same plate ( glass1 expos$ successively to sev]al s\rces ( heat1 dim9i%$ ) ! ?9ness ( ! plate1 & vani%$ altoge!r at a c]ta9 limit2 & t a film ( mica transmitt$ ! same quantity ( heat1 :e!r x 0 expos$ to inc&esc5t plat9um or to a mass ( iron heat$ to #cfj4 ,col\r$ glasses transmit rays ( light ( c]ta9 degrees ( refrangibility1 & absorb ^? ( o!r degrees4 ,= example1 r$ glass absorbs ! m refrangible rays1 & transmits ! r$1 :i* are ! lea/ refrangible4 ,on ! contr>y1 violet glass absorbs ! lea/ refrangible1 & transmits ! violet1 :i* are ! mo/ refrangible4 ,n[ ,m4 ,melloni has f\nd1 t1 al?\gh ! col\r+ matt] ( glass dim9i%es its p[] ( transmitt+ heat1 yet r$1 orange1 yell[1 blue1 violet1 & :ite glass transmit calorific rays ( all degrees ( refrangibility2 :]eas gre5 glass possesses ! peculi> prop]ty ( transmitt+ ! lea/ refrangible calorific rays1 & /opp+ ^? t are mo/ refrangible4 ,x has !re=e ! same elective action = heat t col\r$ glass has = light1 & its action on heat is analog\s to t ( r$ glass on light4 ,alum & sulphate ( lime are exactly oppos$ to gre5 glass 9 _! action on heat1 by transmitt+ ! mo/ refrangible rays ) ! greate/ facility4 ,! heat :i* has already pass$ ?r\gh gre5 or opaque black glass w n pass ?r\gh alum1 :il/ t :i* has be5 transmitt$ ?r\gh glasses ( o!r col\rs trav]ses x readily4 ,by rev]s+ ! exp]im5t1 & expos+ diff]5t sub/ances to heat t _h already pass$ ?r\gh alum1 ,m4 ,melloni f\nd t ! heat em]g+ f alum is almo/ totally int]cept$ by opaque sub/ances1 & is abundantly transmitt$ by all su* z are transp>5t & col\rless1 & t x suff]s no appreciable loss :5 ! ?ickness ( ! plate is v>i$ )9 c]ta9 limits4 ,! prop]ties ( ! heat !re=e :i* issues f alum ne>ly approa* to ^? ( light & sol> heat4 ,radiant heat 9 trav]s+ v>i\s m$ia is n only r5d]$ m or less capable ( be+ transmitt$ a second "t1 b1 accord+ to ! exp]im5ts ( ,pr(essor ,p[ell1 x becomes m or less susceptible ( be+ absorb$ 9 diff]5t quantities by black or :ite surfaces4 ,m4 ,melloni has prov$ t sol> heat conta9s rays :i* are affect$ by diff]5t sub/ances 9 ! same way z if ! heat proce$$ f a t]re/rial s\rce2 :5ce he concludes t ! diff]5ce obs]v$ betwe5 ! transmission ( t]re/rial & sol> heat arises f ! circum/ance ( sol> heat conta9+ all k9ds ( heat1 :il/ 9 o!r s\rces "s ( ! k9ds are want+4 ,radiant heat1 f s\rces ( any temp]ature :atev]1 is subject to ! same laws ( reflection & refraction z rays ( light4 ,! index ( refraction f a prism ( rock-salt1 det]m9$ exp]im5tally1 is ne>ly ! same = light & heat4 ,liquids1 ! v>i\s k9ds ( glass1 & probably all sub/ances1 :e!r solid or liquid1 t d n cry/allize regul>ly1 are m p]vi\s to ! calorific rays accord+ z !y possess a great] refractive p[]4 ,= example1 ! *loride ( sulphur1 :i* has a high refractive p[]1 transmits m ( ! calorific rays ?an ! oils1 :i* h a less refractive p[]3 oils transmit m radiant heat ?an ! acids2 ! acids m ?an aque\s solutions2 & ! latt] m ?an pure wat]1 :i* ( all ! s]ies has ! lea/ refractive p[]1 & is ! lea/ p]vi\s to heat4 ,m4 ,melloni obs]v$ also t ea* ray ( ! sol> spectrum foll[s ! same law ( action ) t ( t]re/rial rays hav+ _! orig9 9 s\rces ( diff]5t temp]atures2 s t ! v refrangible rays may be comp>$ to ! heat emanat+ f a focus ( high temp]ature1 & ! lea/ refrangible to ! heat :i* comes f a s\rce ( l[ temp]ature4 ,?us1 if ! calorific rays em]g+ f a prism be made to pass ?r\gh a lay] ( wat] conta9$ betwe5 two plates ( glass1 x w be f\nd t ^! rays suff] a loss 9 pass+ ?r\gh ! liquid z mu* great] z _! refrangibility is less4 ,! rays ( heat t are mix$ ) ! blue or violet light pass 9 great abundance1 :ile ^? 9 ! obscure "p :i* foll[s ! r$ light are almo/ totally int]cept$4 ,! fir/1 !re=e1 act l ! heat ( a lamp1 & ! la/ l t ( boil+ wat]4 ,^! circum/ances expla9 ! ph5om5a obs]v$ by sev]al philosoph]s ) reg>d to ! po9t ( greate/ heat 9 ! sol> spectrum1 :i* v>ies ) ! sub/ance ( ! prism4 ,sir ,william ,h]s*el1 :o employ$ a prism ( fl9t glass1 f\nd t po9t to be a little beyond ! r$ extremity ( ! spectrum2 b1 accord+ to ,m4 ,seebeck1 x is f\nd to be ^u ! yell[1 ^u ! orange1 on ! r$1 or at ! d>k limit ( ! r$1 accord+ z ! prism consi/s ( wat]1 sulphuric acid1 cr[n or fl9t glass4 ,if x be recollect$ t1 9 ! spectrum f cr[n glass1 ! maximum heat is 9 ! r$ "p1 & t ! sol> rays1 9 trav]s+ a mass ( wat]1 suff] losses inv]sely z _! refrangibility1 x w be easy to und]/& ! reason ( ! ph5om5on 9 "q4 ,! sol> heat :i* comes to ! ant]ior face ( ! prism ( wat] consi/s ( rays ( all degrees ( refrangibility4 ,n[1 ! rays possess+ ! same index ( refraction ) ! r$ light suff] a great] loss 9 pass+ ?r\gh ! prism ?an ! rays possess+ ! refrangibility ( ! orange light1 & ! latt] lose less 9 _! passage ?an ! heat ( ! yell[4 ,?us ! losses1 be+ inv]sely proportional to ! degree ( refrangibility ( ea* ray1 cause ! po9t ( maximum heat to t5d f ! r$ t[>ds ! violet1 & !re=e x re/s ^u ! yell[ "p4 ,! prism ( sulphuric acid1 act+ simil>ly1 b ) less en]gy ?an t ( wat]1 ?r[s ! po9t ( greate/ heat on ! orange2 = ! same reason1 ! cr[n & fl9t glass prisms transf] t po9t respectively to ! r$ & to its limit4 ,m4 ,melloni1 obs]v+ t ! maximum po9t ( heat is transf]r$ f>!r & f>!r t[>ds ! r$ end ( ! spectrum1 accord+ z ! sub/ance ( ! prism is m & m p]meable to heat1 inf]r$ t a prism ( rock-salt1 :i* possesses a great] p[] ( transmitt+ ! calorific rays ?an any kn[n body1 ought to ?r[ ! po9t ( greate/ heat to a consid]able di/ance beyond ! visible "p ( ! spectrum1--an anticipation :i* exp]im5t fully confirm$1 by plac+ x z mu* beyond ! d>k limits ( ! r$ rays z ! r$ "p is di/ant f ! bluei% gre5 b& ( ! spectrum4 ,9 all ^! exp]im5ts ,m4 ,melloni employ$ a !rmomultipli]1--an in/rum5t t measures ! int5sity ( ! transmitt$ heat ) an accuracy f> beyond :at any !rmomet] ev] atta9$4 ,x is a v elegant application ( ,m4 ,seebeck's discov]y ( !rmo-electricity2 b ! description ( ?is in/rum5t is res]v$ = a future occasion1 because ! pr9ciple on :i* x is con/ruct$ has n yet be5 expla9$4 ,9 ! beg9n+ ( ! pres5t c5tury1 n long aft] ,m4 ,malus _h discov]$ ! pol>ization ( light1 he & ,m4 ,b]>d prov$ t ! heat :i* accompanies ! sun's light is capable ( be+ pol>iz$2 b _! attempts totally fail$ ) heat d]iv$ f t]re/rial1 & especially f non-lum9\s s\rces4 ,m4 ,b]>d1 inde$1 imag9$ t he _h succe$$2 b1 :5 8 exp]im5ts 7 repeat$ by ,mr4 ,lloyd & ,pr(essor ,p[ell1 no satisfactory result c\ld be obta9$4 ,m4 ,melloni resum$ ! subject1 & endeav\r$ to effect ! pol>ization ( heat by t\rmal9e1 z 9 ! case ( light4 ,x 0 already %[n t two slices ( t\rmal9e1 cut p>allel to ! axis ( ! cry/al1 transmit a great portion ( ! incid5t light :5 look$ ?r\gh ) _! axes p>allel1 & almo/ entirely exclude x :5 !y are p]p5dicul> to "o ano!r4 ,%\ld radiant heat be capable ( pol>ization1 ! quantity transmitt$ by ! slices ( t\rmal9e 9 _! =m] position ought greatly to exce$ t :i* passes ?r\gh !m 9 ! latt]1 yet ,m4 ,melloni f\nd t ! quantity ( heat 0 ! same 9 bo? cases3 :5ce he inf]r$ t heat f a t]re/rial s\rce is incapable ( be+ pol>iz$4 ,pr(essor ,=bes ( ,ed9burgh1 :o prosecut$ ?is subject ) great acut5ess & success1 came to ! same conclusion 9 ! fir/ in/ance2 b x occurr$ to him1 t1 z ! pieces ( t\rmal9e became heat$ by be+ v ne> ! lamp1 ! second>y radiation f !m r5d]$ ! v small diff]5ce 9 ! heat t 0 transmitt$ 9 ! two positions ( ! pieces ( t\rmal9e imp]ceptible4 ,nev]!less he succe$$ 9 prov+1 by num]\s obs]vations1 t heat f v>i\s s\rces is pol>iz$ by ! t\rmal9e2 b t ! effect ) non-lum9\s heat is v m9ute & difficult to p]ceive1 on acc\nt ( ! second>y radiation4 ,?\gh light is almo/ entirely exclud$ 9 "o position ( ! pieces ( t\rmal9e1 & transmitt$ 9 ! o!r1 a va/ quantity ( radiant heat passes ?r\gh !m 9 all positions4 ,eighty-f\r p] c5t4 ( ! heat f an arg& lamp pass$ ?r\gh !m 9 ! case :]e light 0 altoge!r /opp$4 ,x is only ! diff]5ce 9 ! quantity ( transmitt$ heat t gives evid5ce ( its pol>ization4 ,! second slice ( t\rmal9e1 :5 p]p5dicul> to ! fir/1 /ops all ! light1 b transmits a great proportion ( heat2 alum1 on ! contr>y1 /ops almo/ all ! heat1 & transmits ! light2 :5ce x may be conclud$ t heat1 ?\gh intimately p>tak+ ! nature ( light1 & accompany+ x "u c]ta9 circum/ances1 z 9 reflection & refraction1 is capable ( almo/ complete sep>ation f x "u o!rs4 ,! sep>ation has s9ce be5 p]fectly effect$ by ,m4 ,melloni1 by pass+ a beam ( light ?r\gh a comb9ation ( wat] & gre5 glass1 col\r$ by ! oxide ( copp]4 ,ev5 :5 ! transmitt$ light 0 conc5trat$ by l5ses1 s z to r5d] x almo/ z brilliant z ! direct light ( ! sun1 x %[$ no s5sible heat4 ,pr(essor ,=bes next employ$ two bundles ( lam9 ( mica1 plac$ at ! pol>iz+ angle1 & s cut t ! plane ( incid5ce ( ! heat correspond$ ) "o ( ! optic axes ( ?is m9]al4 ,! heat transmitt$ ?r\gh ?is app>atus 0 pol>iz$ f a s\rce ^: temp]ature 0 ev5 z l[ z #bjj2 heat 0 also pol>iz$ by reflection2 b ! exp]im5ts1 ?\gh p]fectly successful1 are m difficult to conduct4 ,x appe>s1 f ! v>i\s exp]im5ts ( ,m4 ,melloni & ,pr(essor ,=bes1 t all ! calorific rays emanat+ f ! sun & t]re/rial s\rces are equally capable ( be+ pol>iz$ by reflection & by refraction1 :e!r d\ble or s+le1 & t !y are also capable ( circul> pol>ization by all ! me?ods employ$ 9 ! circul> pol>ization ( light4 ,plates ( qu>tz cut at "r angles to ! axis ( ! prism possess ! prop]ty ( turn+ ! calorific rays 9 "o direction1 :ile o!r plates ( ! same sub/ance f a diff]5tly modifi$ prism cause ! rays to rotate 9 ! contr>y direction2 & two plates comb9$1 :5 ( diff]5t affection1 & ( equal ?ickness1 c\nt]act ea* o!r's effects z 9 ! case ( light4 ,t\rmal9e sep>ates ! heat into two p>ts1 "o ( :i* x absorbs1 :ile x transmits ! o!r2 9 %ort1 ! transmission ( radiant heat is precisely simil> to t ( light4 ,s9ce heat is pol>iz$ 9 ! same mann] z light1 x may be expect$ t pol>iz$ heat transmitt$ ?r\gh d\bly refract+ sub/ances %\ld be sep>at$ into two p5cils1 pol>iz$ 9 planes at "r angles to ea* o!r2 & t :5 receiv$ on an analyz+ plate !y %\ld int]f]e & produce invisible ph5om5a1 p]fectly analog\s to ^? describ$ 9 ,section ,,xxii4 ) reg>d to light 7,n4 #bba74 ,x 0 %[n1 9 ! same section1 t if light pol>iz$ by reflection f a pane ( glass be view$ ?r\gh a plate ( t\rmal9e1 ) its longitud9al section v]tical1 an obscure cl\d1 ) its c5tre :olly d>k1 is se5 on ! glass4 ,:51 h[ev]1 a plate ( mica uni=mly ab\t ! ?irte5? ( an in* 9 ?ickness is int]pos$ betwe5 ! t\rmal9e & ! glass1 ! d>k spot vani%es1 & a succession ( v spl5did col\rs are se52 &1 z ! mica is turn$ r\nd 9 a plane p]p5dicul> to ! pol>iz$ ray1 ! light is /opp$ :5 ! plane conta9+ ! optic axis ( ! mica is p>allel or p]p5dicul> to ! plane ( pol>ization4 ,n[1 in/ead ( light1 if heat f a non-lum9\s s\rce be pol>iz$ 9 ! mann] describ$1 x ought to be transmitt$ & /opp$ by ! int]pos$ mica "u ! same circum/ances "u :i* pol>iz$ light w\ld be transmitt$ or /opp$4 ,pr(essor ,=bes f\nd t ?is is really ! case1 :e!r he employ$ heat f lum9\s or non-lum9\s s\rces3 & he _h evid5ce1 also1 ( circul> & elliptical pol>ization ( heat4 ,x !re=e foll[s1 t if heat 7 visible1 "u simil> circum/ances we %\ld see figures p]fectly simil> to ^? giv5 9 ,note #bac1 & ^? foll[+2 &1 z ^! figures are =m$ by ! int]f]5ce ( undulations ( light1 x may be inf]r$ t heat1 l light1 is propagat$ by undulations ( ! e!real m$ium1 :i* int]f]e "u c]ta9 conditions1 & produce figures analog\s to ^? ( light4 ,x appe>s also1 f ,mr4 ,=bes's exp]im5ts1 t ! undulations ( heat are long] ?an ! undulations ( light2 & x has already be5 m5tion$ t ,pr(essor ,drap] consid]s !m to be normal1 l ^? ( s\nd4 ,t light & heat are bo? vibrations ( ! e!real m$ium is n ! less true on acc\nt ( ! rays ( heat be+ unse51 = ! condition ( visibility or invisibility may only dep5d ^u ! con/ruction ( our eyes1 & n ^u ! nature ( ! motion :i* produces ^! s5sations 9 u4 ,! s5se ( see+ may be conf9$ )9 c]ta9 limits4 ,! *emical rays beyond ! violet end ( ! spectrum may be too rapid1 or n suffici5tly excursive1 9 _! vibrations1 to be visible to ! human eye2 & ! calorific rays beyond ! o!r end ( ! spectrum may n be suffici5tly rapid1 or too ext5sive1 9 _! undulations1 to affect our optic n]ves1 ?\gh bo? may be visible to c]ta9 animals or insects4 ,we are altoge!r ignorant ( ! p]ceptions :i* direct ! c>ri]-pigeon to 8 home1 or ( ^? 9 ! ant5n ( insects :i* w>n !m ( ! approa* ( dang]2 nor c we und]/& ! telescopic vision :i* directs ! vulture to 8 prey be=e he himself is visible ev5 z a speck 9 ! heav5s4 ,s1 likewise1 be+s may exi/ on e>?1 9 ! air1 or 9 ! wat]s1 :i* he> s\nds our e>s are incapable ( he>+1 & :i* see rays ( light & heat ( :i* we are unconsci\s4 ,our p]ceptions & faculties are limit$ to a v small portion ( t imm5se *a9 ( exi/5ce :i* ext5ds f ! ,creator to evanesc5ce4 ,! id5tity ( action "u simil> circum/ances is "o ( ! /ronge/ argum5ts 9 fav\r ( ! common nature ( ! *emical1 visible1 & calorific rays4 ,!y are all capable ( reflection f poli%$ surfaces1 ( refraction ?r\gh diaphan\s sub/ances1 ( pol>ization by reflection & by d\bly refract+ cry/als2 _! velocity is prodigi\s2 !y may be conc5trat$ & disp]s$ by convex & concave mirrors2 !y pass ) equal facility ?r\gh rock-salt & are capable ( radiation2 & !y are subject to ! same law ( int]f]5ce ) ^? ( light3 h5ce !re c be no d\bt t ! :ole assemblage ( rays visible & invisible :i* con/itute a sol> beam are propagat$ by ! undulations ( ! e!real m$ium1 & consequ5tly z motions !y come "u ! same laws ( analysis4 ,:5 radiant heat falls ^u a surface1 "p ( x is reflect$ & "p ( x is absorb$2 consequ5tly1 ! be/ reflectors possess ! lea/ absorb+ p[]s4 ,! temp]ature ( v transp>5t fluids is n rais$ by ! passage ( ! sun's rays1 because !y d n absorb any ( !m2 &1 z 8 heat is v int5se1 transp>5t solids arre/ a v small portion ( x4 ,! absorption ( ! sun's rays is ! cause bo? ( ! col\r & temp]ature ( solid bodies4 ,a black sub/ance absorbs all ! rays ( light1 & reflects none2 & s9ce x absorbs1 at ! same "t1 all ! calorific rays1 x becomes soon] w>m1 & rises to a high] temp]ature1 ?an bodies ( any o!r col\r4 ,blue bodies come next to black 9 _! p[] ( absorption4 ,&1 s9ce sub/ances ( a blue t9t absorb all ! o!r col\rs ( ! spectrum1 !y absorb by f> ! greate/ "p ( ! calorific rays1 & reflect ! blue :]e !y are lea/ abundant4 ,next 9 ord] come ! gre51 yell[1 r$1 &1 la/ ( all1 :ite bodies1 :i* reflect ne>ly all ! rays bo? ( light & heat4 ,h[ev]1 !re are c]ta9 limpid & col\rless m$ia1 :i* 9 "s cases int]cept calorific radiations & become heat$1 :ile 9 o!r cases !y transmit !m & und]go no *ange ( temp]ature4 ,all sub/ances may be consid]$ to radiate heat1 :atev] _! temp]ature may be1 ?\gh ) diff]5t int5sities1 accord+ to _! nature1 ! /ate ( _! surfaces1 & ! temp]ature ( ! m$ium into :i* !y are br\ght4 ,b e surface absorbs z well z radiates heat2 & ! p[] ( absorption is always equal to t ( radiation2 =1 "u ! same circum/ances1 matt] :i* becomes soon w>m also cools rapidly4 ,!re is a con/ant t5d5cy to an equal diffusion ( heat1 s9ce e body 9 nature is giv+ & receiv+ x at ! same in/ant2 ea* w be ( uni=m temp]ature :5 ! quantities ( heat giv5 & receiv$ dur+ ! same "t are equal--t is1 :5 a p]fect comp5sation takes place betwe5 ea* & all ! re/4 ,our s5sations only measure comp>ative degrees ( heat3 :5 a body1 su* z ice1 appe>s to be cold1 x imp>ts few] calorific rays ?an x receives2 & :5 a sub/ance seems to be w>m--= example1 a fire--x gives m heat ?an x takes4 ,! ph5om5a ( dew & ho>-fro/ are ow+ to ?is inequality ( ex*ange2 ! heat radiat$ dur+ ! night by sub/ances on ! surface ( ! e>?1 into a cle> expanse ( sky1 is lo/ to u1 & no return is made f ! blue vault1 s t _! temp]ature s9ks bel[ t ( ! air1 :5ce !y ab/ract a "p ( t heat :i* holds ! atmosph]ic humidity 9 solution1 & a deposition ( dew takes place4 ,if ! radiation be great1 ! dew is froz5 & becomes ho>-fro/1 :i* is ! ice ( dew4 ,cl\dy wea!r is unfav\rable to ! =mation ( dew1 by prev5t+ ! free radiation ( heat2 & actual contact is requisite = its deposition1 s9ce x is nev] susp5d$ 9 ! air l fog4 ,plants d]ive a great "p ( _! n\ri%m5t f ?is s\rce2 &1 z ea* possesses a p[] ( radiation peculi> to itself1 !y are capable ( procur+ a suffici5t supply = _! wants4 ,! action ( ! *emical rays imp>ts to all sub/ances m or less ! p[] ( cond5s+ vap\r on ^? p>ts on :i* !y fall1 & mu/ !re=e h a consid]able influ5ce on ! deposition ( dew4 ,!re may be a l[ degree ( humidity 9 ! air :i* may yet conta9 a great quantity ( aque\s vap\r1 = vap\r :ile x exi/s z gas is dry4 ,! temp]ature at :i* ! atmosph]e c conta9 no m vap\r )\t precipitation is call$ ! dew po9t1 & is measur$ by ! hygromet]4 ,9 =etell+ ! *anges ( wea!r x is sc>cely inf]ior to ! b>omet]4 ,/eam is =m$ ?r\gh\t ! :ole mass ( a boil+ liquid1 :]eas evaporation takes place only at ! free surface ( liquids1 & t "u ! ord9>y temp]ature & pressure ( ! atmosph]e4 ,!re is a con/ant evaporation f ! l& & wat] all ov] ! e>?4 ,! rapidity ( ! =mation does n dep5d altoge!r on ! dryness ( ! air2 accord+ to ,dr4 ,dalton's exp]im5ts1 x dep5ds also on ! diff]5ce betwe5 ! t5sion ( ! vap\r :i* is =m+1 & t :i* is already 9 ! atmosph]e4 ,9 calm wea!r vap\r accumulates 9 ! /ratum ( air imm$iately above ! evaporat+ surface1 & ret>ds ! =mation ( m2 :]eas a /rong w9d accel]ates ! process by c>ry+ (f ! vap\r z soon z x rises1 & mak+ way = a succe$+ portion ( dry air4 ,ra9 is =m$ by ! mix+ ( two masses ( air ( diff]5t temp]atures2 ! cold] "p1 by ab/ract+ f ! o!r ! heat :i* holds x 9 solution1 occasions ! p>ticles to approa* ea* o!r & =m drops ( wat]1 :i*1 becom+ too heavy to be su/a9$ by ! atmosph]e1 s9k to ! e>? by gravitation 9 ! =m ( ra94 ,! contact ( two /rata ( air ( diff]5t temp]atures1 mov+ rapidly 9 opposite directions1 occasions an abundant precipitation ( ra94 ,:5 ! masses ( air diff] v mu* 9 temp]ature1 & meet sudd5ly1 hail is =m$4 ,?is happ5s frequ5tly 9 hot pla9s ne> a ridge ( m\nta9s1 z 9 ! s\? ( ,france1 f ! sudd5 desc5t ( an int5sely cold curr5t ( w9d into a mass ( air ne>ly saturat$ ) vap\r4 ,su* also is ! cause ( ! sev]e hail-/orms :i* occasionally take place on ext5sive pla9s )9 ! tropics4 ,an accumulation ( heat inv>iably produces light3 ) ! exception ( ! gases1 all bodies :i* c endure ! requisite degree ( heat )\t decomposition beg9 to emit light at ! same temp]ature2 b1 :5 ! quantity ( heat is s great z to r5d] ! aff9ity ( _! compon5t p>ticles less ?an _! aff9ity = ! oxyg5 ( ! atmosph]e1 a *emical comb9ation takes place ) ! oxyg51 light & heat are evolv$1 & fire is produc$4 ,combu/ion--s ess5tial = our com=t1 & ev5 exi/5ce--takes place v easily f ! small aff9ity betwe5 ! compon5t p>ts ( atmosph]ic air1 ! oxyg5 be+ ne>ly 9 a free /ate2 b1 z ! cohesive =ce ( ! p>ticles ( diff]5t sub/ances is v v>iable1 diff]5t degrees ( heat are requisite to produce _! combu/ion4 ,! t5d5cy ( heat to a /ate ( equal diffusion or equilibrium1 ei!r by radiation or contact1 makes x necess>y t ! *emical comb9ation :i* occasions combu/ion %\ld take place in/antane\sly2 =1 if ! heat 7 develop$ progressively1 x w\ld be dissipat$ by degrees1 & w\ld nev] accumulate suffici5tly to produce a temp]ature high en\gh = ! evolution ( flame4 ,x is a g5]al law t all bodies exp& by heat & contract by cold4 ,! expansive =ce ( heat has a con/ant t5d5cy to ov]come ! attraction ( cohesion1 & to sep>ate ! con/itu5t p>ticles ( solids & fluids2 by ?is sep>ation ! attraction ( aggregation is m & m weak5$1 till at la/ x is entirely ov]come1 or ev5 *ang$ into repulsion4 ,by ! cont9ual addition ( heat1 solids may be made to pass into liquids1 & f liquids to ! ari=m /ate1 ! dilatation increas+ ) ! temp]ature2 & e sub/ance exp&s accord+ to a law ( its own4 ,gases exp& m ?an liquids1 & liquids m ?an solids4 ,! expansion ( air is m ?an eight times t ( wat]1 & ! increase 9 ! bulk ( wat] is at lea/ =ty-five times great] ?an t ( iron4 ,metals dilate uni=mly f ! freez+ to ! boil+ po9ts ( ! !rmomet]2 ! uni=m expansion ( ! gases ext5ds betwe5 /ill wid] limits2 b1 z liquidity is a /ate ( transition f ! solid to ! ari=m condition1 ! equable dilatation ( liquids has n s ext5sive a range4 ,?is *ange ( bulk1 correspond+ to ! v>iation ( heat1 is "o ( ! mo/ important ( its effects1 s9ce x furni%es ! means ( measur+ relative temp]ature by ! !rmomet] & pyromet]4 ,! rate ( expansion ( solids v>ies at _! transition to liquidity1 & t ( liquidity is no long] equable ne> _! *ange to an ari=m /ate4 ,!re are exceptions1 h[ev]1 to ! g5]al laws ( expansion2 "s liquids h a maximum d5sity correspond+ to a c]ta9 temp]ature1 & dilate :e!r t temp]ature be increas$ or dim9i%$4 ,= example--wat] exp&s :e!r x be heat$ above or cool$ bel[ #dj4 ,! solidification ( "s liquids1 & especially _! cry/allization1 is always accompani$ by an increase ( bulk4 ,wat] dilates rapidly :5 conv]t$ into ice1 & ) a =ce suffici5t to split ! h>de/ sub/ances4 ,! =mation ( ice is !re=e a p[]ful ag5t 9 ! dis9tegration & decomposition ( rocks1 op]at+ z "o ( ! mo/ effici5t causes ( local *anges 9 ! /ructure ( ! cru/ ( ! e>?2 ( :i* we h exp]i5ce 9 ! trem5d\s b\lem5s ( m\nta9s 9 ,switz]l&4 ,b ,pr(essor ,w4 ,?omson has prov$ exp]im5tally t x requires a l[] temp]ature to freeze wat] "u pressure ?an :5 free4 ,! dilatation ( sub/ances by heat1 & _! contraction by cold1 occasion su* irregul>ities 9 ! rate ( clocks & wat*es z w\ld r5d] !m unfit = a/ronomical or nautical purposes1 7 x n = a v beautiful application ( ! laws ( unequal expansion4 ,! oscillations ( a p5dulum are ! same z if its :ole mass 7 unit$ 9 "o d5se p>ticle1 9 a c]ta9 po9t ( its l5g?1 call$ ! c5tre ( oscillation4 ,if ! di/ance ( ?is po9t f ! po9t by :i* ! p5dulum is susp5d$ 7 inv>iable1 ! rate ( ! clock w\ld be inv>iable also4 ,! difficulty is to neutralize ! effects ( temp]ature1 :i* is p]petually increas+ or dim9i%+ its l5g?4 ,among _m contrivances1 ,graham's comp5sation p5dulum is ! mo/ simple4 ,he employ$ a glass tube conta9+ m]cury4 ,:5 ! tube exp&s f ! effects ( heat1 ! m]cury exp&s mu* m2 s t its surface rises a little m ?an ! end ( ! p5dulum is depress$1 & ! c5tre ( oscillation rema9s /ation>y4 ,h>rison inv5t$ a p5dulum :i* consi/s ( sev5 b>s ( /eel & ( brass1 jo9$ 9 ! %ape ( a gridiron1 9 su* a mann] t1 if by *ange ( temp]ature ! b>s ( brass raise ! weight at ! end ( ! p5dulum1 ! b>s ( /eel depress x z mu*4 ,9 g5]al1 only five b>s are us$2 ?ree be+ ( /eel1 & two a mixture ( silv] & z9c4 ,! effects ( temp]ature are neutraliz$ 9 *ronomet]s ^u ! same pr9ciple2 & to su* p]fection are !y br\ght1 t ! loss or ga9 ( "o second 9 tw5ty-f\r h\rs = two days runn+ w\ld r5d] "o unfit = use4 ,accuracy 9 survey+ dep5ds ^u ! comp5sation rods employ$ 9 measur+ bases4 ,?us1 ! laws ( ! unequal expansion ( matt] judici\sly appli$ h an imm$iate influ5ce ^u our e/imation ( "t2 ( ! motions ( bodies 9 ! heav5s1 & ( _! fall ^u ! e>?2 on our det]m9ation ( ! figure ( ! globe1 & on our sy/em ( weights & measures2 on our comm]ce abroad1 & ! m5suration ( our l&s at home4 ,! expansion ( ! cry/all9e sub/ances takes place "u v diff]5t circum/ances f ! dilatation ( su* z are n cry/alliz$4 ,! latt] become bo? long] & ?ick] by an accession ( heat1 :]eas ,m4 ,mits*]li* has f\nd t ! =m] exp& diff]5tly 9 diff]5t directions2 &1 9 a p>ticul> in/ance1 ext5sion 9 "o direction is accompani$ by contraction 9 ano!r3 = example1 ,icel& sp> is dilat$ 9 ! direction ( its axis ( d\ble refraction 7,n4 #bje71 b at "r angles to t axis x is contract$1 :i* br+s ! cry/al ne>] to ! =m ( ! cube & dim9i%es its d\ble refractive p[]4 ,:5 heat is appli$ to cry/als ( sulphate ( lime1 ! two optical axes 7,n4 #bjg7 gradually approa*1 & at la/ co9cide2 :5 ! heat is increas$1 ! axes op5 aga91 b 9 a direction at "r angles to _! =m] position4 ,by exp]im5t ,m4 ,s5>mont has conclud$1 t 9 m$ia con/itut$ l cry/als ( ! rhomboidal 7,n4 #afi7 sy/em ! conduct+ p[] v>ies 9 su* a mann]1 t1 suppos+ a c5tre ( heat to exi/ )9 !m1 & ! m$ium to be indef9itely ext5d$ 9 all directions1 ! iso!rmal surfaces are conc5tric ellipsoids ( revolution r\nd ! axes ( symmetry1 or at lea/ surfaces diff]+ b little f !m4 ,! int]nal /ructure ( cry/alliz$ matt] mu/ be v peculi> ?us to modify ! expansive p[] ( heat4 ,heat appli$ to ! surface ( a fluid is propagat$ d[nw>ds v sl[ly1 ! w>m]1 & consequ5tly light] /rata1 always rema9+ at ! top4 ,?is is ! reason :y ! wat] at ! bottom ( lakes f$ f ,alp9e *a9s is s cold2 = ! heat ( ! sun is transfus$ b a little way bel[ ! surface4 ,:5 ! heat is appli$ bel[ a liquid1 ! p>ticles cont9ually rise z !y become specifically light]1 & diffuse ! heat ?r\gh ! mass1 _! place be+ p]petually suppli$ by ^? t are m d5se4 ,! p[] ( conduct+ heat v>ies mat]ially 9 diff]5t liquids4 ,m]cury conducts twice z fa/ z an equal bulk ( wat]1 & !re=e x appe>s to be v cold4 ,a hot body diffuses its heat 9 ! air by a d\ble process3 ! air 9 contact ) x becom+ light] asc5ds & scatt]s its heat by transmission1 :ile at ! same "t ano!r portion is dis*>g$ 9 /raight l9es by ! radiat+ p[] ( ! surface4 ,h5ce a sub/ance cools m rapidly 9 air ?an 9 vacuo1 because 9 ! latt] case ! process is c>ri$ on by radiation alone4 ,x is probable t ! e>? hav+ be5 orig9ally ( v high temp]ature has become cool] by radiation alone1 ! e!real m$ium be+ too r>e to c>ry (f mu* heat by contact4 ,heat is propagat$ ) m or less rapidity ?r\gh all bodies2 air is ! wor/ conductor1 & consequ5tly mitigates ! sev]ity ( cold climates by pres]v+ ! heat imp>t$ to ! e>? by ! sun4 ,on ! contr>y1 d5se bodies1 especially metals1 possess ! p[] ( conduction 9 ! greate/ degree1 b ! transmission requires "t4 ,if a b> ( iron tw5ty in*es long be heat$ at "o extremity1 ! heat takes f\r m9utes 9 pass+ to ! o!r4 ,! p>ticle ( ! metal t is fir/ heat$ communicates ! heat to ! second1 & ! second to ! ?ird3 s t ! temp]ature ( ! int]m$iate molecule at any in/ant is increas$ by ! excess ( ! temp]ature ( ! fir/ above its own1 & dim9i%$ by ! excess ( its own temp]ature above t ( ! ?ird4 ,t h[ev] w n be ! temp]ature indicat$ by ! !rmomet]1 because z soon z ! p>ticle is m heat$ ?an ! surr\nd+ atmosph]e x loses its heat by radiation1 9 proportion to ! excess ( its actual temp]ature above t ( ! air4 ,! velocity ( ! dis*>ge is directly proportional to ! temp]ature1 & inv]sely z ! l5g? ( ! b>4 ,z !re are p]petual v>iations 9 ! temp]ature ( all t]re/rial sub/ances1 & ( ! atmosph]e1 f ! rotation ( ! e>?1 & its revolution r\nd ! sun1 f combu/ion1 friction1 f]m5tation1 electricity1 & an inf9ity ( o!r causes1 ! t5d5cy to re/ore ! equability ( temp]ature by ! transmission ( heat mu/ ma9ta9 all ! p>ticles ( matt] 9 a /ate ( p]petual oscillation1 :i* w be m or less rapid accord+ to ! conduct+ p[]s ( ! sub/ances4 ,f ! motion ( ! heav5ly bodies ab\t _! axes1 & also r\nd ! sun1 expos+ !m to p]petual *anges ( temp]ature1 x may be inf]r$ t simil> causes w produce l effects 9 !m too4 ,! revolutions ( ! d\ble />s %[ t !y are n at re/2 & al?\gh we are totally ignorant ( ! *anges t may be go+ on 9 ! nebul & millions ( o!r remote bodies1 x is h>dly possible t !y %\ld be 9 absolute repose2 s t1 z f> z our k ext5ds1 motion is a law ( ! univ]se & ! imm$iate cause ( heat1 z 9 ! sunbeam s also 9 all t]re/rial ph5om5a4 ,?is is by no means hypo!tical1 b f\nd$ ^u fact & exp]im5t4 ,heat is produc$ by motion & is equival5t to x1 = we measure heat by motion 9 ! !rmomet]4 ,! heat evolv$ by p]cussion is proportional to ! =ce ( ! bl[2 by repeat$ bl[s iron becomes r$ hot2 & ! quantity ( heat produc$ by friction1 :e!r ! matt] be solid or fluid1 is always 9 proportion to ! =ce employ$3 9 cold wea!r we rub our h&s to make !m w>m1 & ! h>d] we rub ! w>m] !y become4 ,! w>m? ( ! sea aft] a /orm is 9 proportion to ! =ce ( ! w9d2 & 9 ,sir ,humphry ,davy's exp]im5t ( melt+ ice by friction 9 ! receiv] ( an air-pump kept at ! freez+ po9t1 ! heat :i* melt$ ! ice 0 exactly proportional to ! =ce ( friction4 ,?is exp]im5t proves ! immat]iality ( heat1 s9ce ! capacity ( ice = heat is less ?an t ( wat]4 ,?us me*anical action & heat are equival5t to "o ano!r4 ,mr4 ,j\le ( ,man*e/]#ac has prov$ t ! quantity ( heat requisite to raise ! temp]ature ( a p\nd ( wat] "o degree ( ,fahr5heit's !rmomet]1 is equival5t to ! me*anical =ce develop$ by ! fall ( a body weigh+ #ggbfi p\nds ?r\gh ! p]p5dicul> height ( "o foot4 ,?is quantity is ! me*anical equival5t ( heat4 ,?us heat is motion1 & x is measur$ by =ce4 ,9 fact1 = e unit ( =ce exp5d$ 9 friction or p]cussion1 a def9ite quantity ( heat is g5]at$2 & conv]sely1 :5 "w is p]=m$ by ! consumption ( heat1 = ea* unit ( =ce ga9$1 a unit ( heat disappe>s4 ,= s9ce heat is a dynamical =ce ( me*anical effect1 !re mu/ be an equival5t betwe5 me*anical "w & heat z betwe5 cause & effect4 7,n4 #bbb47 ,besides ! temp]ature indicat$ by ! !rmomet]1 bodies absorb heat1 & _! capacity = heat is s v>i\s t v diff]5t quantities ( heat are requir$ to raise diff]5t sub/ances to ! same s5sible temp]ature4 ,x is evid5t1 !re=e1 t mu* ( ! heat is absorb$ & becomes ins5sible to ! !rmomet]4 ,t portion ( heat requisite to raise a body to a giv5 temp]ature is its specific heat1 b ! lat5t or absorb$ heat is an expansive =ce or en]gy1 :i*1 act+ ^u ! e!r surr\nd+ ! ultimate p>ticles ( bodies1 *anges !m f solid to liquid1 & f liquid to vap\r or gas4 ,accord+ to ! law ( absorption1 ! transf] ( heat f a w>m body to "o t is cold is a m]e transf] ( =ce1 9 :i* ! =ce ( compression is exactly proportional to ! =ce ( expansion4 ,ice rema9s at ! temp]ature ( #cb ,fahr5heit till x has absorb$ #adj ( heat1 & !n x melts1 b )\t rais+ ! temp]ature ( ! wat] above #cb4 ,on ! contr>y1 :5 a liquid is conv]t$ into a solid1 a quantity ( heat leaves x )\t any dim9ution ( temp]ature4 ,?us wat] at #cb mu/ "p ) #adj ( heat be=e x freezes4 ,! sl[ness ) :i* wat] freezes or ice ?aws1 is a consequ5ce ( ! "t requir$ = ! e!real atmosph]es r\nd ! p>ticles ( ! wat] to contract or exp& ) a =ce equival5t to #adj ( heat4 ,a consid]able degree ( cold is felt dur+ a ?aw1 because ! ice 9 its transition f a solid to a liquid /ate absorbs s5sible heat f ! atmosph]e & surr\nd+ objects4 ,! heat absorb$ & evolv$ by ! r>efaction & cond5sation ( air is exactly proportional to ! =ce evolv$ & absorb$ 9 ^! op]ations4 ,9 fact1 ! *anges ( temp]ature produc$ by ^! r>efactions & cond5sations ( air %[ t ! heat ( ela/ic fluids is ! me*anical =ce possess$ by !m2 & s9ce ! temp]ature ( a gas det]m9es its ela/ic =ce1 x foll[s t ! ela/ic =ce or pressure mu/ be ! effect ( ! motion ( ! con/itu5t p>ticles 9 any gas4 ,sir ,humphry ,davy1 :o fir/ demon/rat$ ! immat]iality ( heat1 assum$ ! hypo!sis t ! motion we call heat is a rotation or vibration among ! p>ticles ( ! fluid1 :i*1 accord+ to ,mr4 ,j\le1 agrees p]fectly ) ! obs]v$ ph5om5a1 b he pref]s ! m simple view ( ,mr4 ,h]apa?1 t ! ela/ic =ce or pressure is due to ! impact ( ! p>ticles aga9/ any surface pres5t$ to !m4 ,absorb$ or lat5t heat may be reg>d$ z a quiesc5t en]gy ready to be re/or$ to ! =m ( s5sible heat :5 call$ =?3 its vibrations z heat are ext+ui%$ = ! "t by be+ transf]r$ to ! int]nal expansive =ce1 & are re/or$ by compression4 ,! absorb$ heat ( air & all ela/ic fluids may be =c$ out by sudd5 compression l squeez+ wat] out ( a sponge4 ,! quantity ( heat br\ght into action 9 ?is way is well illu/rat$ by ! exp]im5t ( ignit+ t9d] by ! sudd5 compression ( air by a pi/on ?ru/ into a cyl9d] clos$ at "o end4 ,! developm5t ( heat on a /up5d\s scale is exhibit$ 9 lightn+3 x is proportional to ! squ>e ( ! quantity ( electricity dis*>g$1 & is due to its excessive velocity & ! viol5t compression ( ! air 9 its transit ?r\gh ! atmosph]e4 ,prodigi\s quantities ( heat are con/antly absorb$ or dis5gag$ by ! *anges to :i* sub/ances are liable 9 pass+ f ! solid to ! liquid & f ! liquid to ! gase\s =m & ! contr>y1 caus+ endless vicissitudes ( temp]ature ov] ! globe1 & endless expansions & contractions1 :i* are correlative t]ms = heat & cold1 :ile radiation ( heat is m]ely a transf] ( motion f ! p>ticles on ! surface ( bodies to ! adjac5t p>ticles ( ! atmosph]e4 ,by ! cont9ual application ( heat1 t is ( ! expansive =ce1 liquids are conv]t$ into /eam or vap\r1 :i* is invisible & highly ela/ic4 ,"u ! mean pressure ( ! atmosph]e1 t is :5 ! b>omet] /&s at #cj in*es1 wat] 9 a boil] absorbs heat cont9ually till x atta9s ! temp]ature ( ! boil+ po9t1 :i* is #bab ,fahr5heit4 ,aft] t x ceases to %[ any increase ( s5sible heat2 b :5 x has absorb$ an additional #ajjj ( heat or expansive en]gy1 t en]gy conv]ts x into /eam1 & a cond5s+ =ce equival5t to #ajjj ( heat r$uces x aga9 to wat]4 ,wat] boils at diff]5t temp]atures "u diff]5t degrees ( pressure4 ,x boils at a l[] temp]ature on ! top ( a m\nta9 ?an on ! pla9 bel[1 because ! weight ( ! atmosph]e is less at ! high] /ation4 ,!re is no limit to ! temp]ature to :i* wat] might be rais$3 x might ev5 be made r$ hot1 c\ld a vessel be f\nd /rong en\gh to resi/ ! pressure1 = ! int5sity ( ! expansive =ce prev5t$ f hav+ effect by ! extreme pressure ( ! boil] w\ld be conv]t$ into s5sible heat :i* might ev5tually r5d] ! wat] r$ hot4 ,?us1 s9ce ! =ce ( /eam is 9 proportion to ! temp]ature at :i* ! wat] boils1 or to ! pressure1 x is "u control1 &1 p]haps ) ! exception ( electricity1 x is ! greate/ p[] t has be5 made subs]vi5t to ! wants ( man4 ,x is f\nd t ! absolute quantity ( heat consum$ 9 ! process ( conv]t+ wat] into /eam is ! same at :atev] temp]ature wat] may boil1 b t ! absolute heat ( ! /eam is great] exactly 9 proportion z its s5sible heat is less4 ,?us1 /eam rais$ at #bab ,fahr5heit "u ! mean pressure ( ! atmosph]e1 & /eam rais$ at #ahj "u half ! pressure1 conta9 ! same quantity ( heat1 ) ?is diff]5ce1 t ! "o has m absorb$ heat & less s5sible heat ?an ! o!r4 ,x is evid5t t1 z ! same quantity ( heat is requisite = conv]t+ a giv5 weight ( wat] into /eam1 at :atev] temp]ature or "u :atev] pressure ! wat] may be boil$1 !re=e1 9 ! /eam eng9e1 equal weights ( /eam at a high pressure & a l[ pressure are produc$ by ! same quantity ( fuel2 & :atev] ! pressure ( ! /eam may be1 ! consumption ( fuel is proportional to ! quantity ( wat] conv]t$ into vap\r4 ,/eam ( :atev] t5sion exp&s on be+ set free1 b ! expansion ( high pressure /eam at ! exp5se ( its s5sible heat is s great1 t ! h& may be plung$ into x )\t injury ! in/ant x issues f ! orifice ( a boil]4 ,! /eam becomes hott] by friction 9 issu+ ?r\gh ! orifice :i* ma9ta9s x 9 its dry =m1 = !re is no d\bt t high-pressure /eam is dry4 ,! ela/icity or t5sion ( /eam1 l t ( common air1 v>ies inv]sely z its volume--t is1 :5 ! space x occupies is d\bl$1 its ela/ic =ce is r$uc$ to "o half4 ,! expansion ( /eam is indef9ite2 ! smalle/ quantity ( wat] exp&$ into vap\r w occupy _m millions ( cubic feet2 a wond]ful illu/ration ( ! m9ut5ess ( ! ultimate p>ticles ( matt]4 ,! =ce ( /eam1 trem5d\s z ! lightn+ itself :5 uncontroll$1 is m]ely ! result ( *emical aff9ity3 x is ! *emical attraction betwe5 ! p>ticles ( c>bon1 ( coal or wood1 & ! oxyg5 ( ! atmosph]e4 ,mr4 ,j\le has asc]ta9$ t a p\nd ( ! be/ coal :5 burnt gives suffici5t heat to raise ! temp]ature ( #hjhf p\nds ( wat] "o degree ( ! ,c5tigrade !rmomet]1 :5ce x has be5 comput$ by ,m4 ,helmholtz t ! *emical =ce aris+ f ! combu/ion ( t p\nd ( coal is capable ( lift+ a body ( "o hundr$ p\nds weight to ! height ( tw5ty miles4 ,t is ! "w p]=m$ by ! heat aris+ f ! combu/ion ( a p\nd ( coal4 ,9 all cases :]e "w is produc$ by heat1 a quantity ( heat proportional to ! "w done is exp5d$2 & conv]sely1 by ! exp5diture ( a l quantity ( "w1 ! same am\nt ( heat may be produc$4 ,! equival5ce ( heat & "w is a law ( nature4 ,! me*anical =ce ex]t$ by ! /eam eng9e = example is exactly proportional to ! consumption ( heat1 nor m nor less2 if we c\ld produce a great] quantity ?an its equival5t we %\ld h p]petual motion1 :i* is impossible4 ,me*anical eng9es g5]ate no =ce4 ,we _c create =ce2 we c only avail ourselves ( ! inexhau/ible /ores ( nature1 ! lightn+1 fire1 wat]1 w9d1 *emical action1 c4 ,! quantity ( me*anical p[] 9 nature is ev] ! same2 x is nev] increas$1 x is nev] dim9i%$1 ?r\gh\t ! :ole circuit ( natural p[]s4 ,! cons]vation ( =ce is z p]man5t & un*angeable z matt]4 ,x may be dormant = a "t1 b x ev] exi/s4 ,we are unconsci\s ( ! enorm\s dynamic p[] t is ei!r active or lat5t ?r\gh\t ! globe1 because we d n att5d to x4 ,by ! ebb & fl[ ( ! tide alone a p[] is ex]t$ by :i* #be1jjj cubic miles ( wat] is mov$ ov] a qu>t] ( ! globe e twelve h\rs2 & ,pr(essor ,w4 ,?omson has comput$1 by means ( ,p\illet's data ( sol> radiation & ,mr4 ,j\le's me*anical equival5t ( heat1 t ! me*anical value ( ! :ole en]gy active & pot5tial ( ! di/urbances kept up 9 ! e!real m$ium by ! vibrations ( ! sol> light )9 a cubic mile ( our atmosph]e is equal to #ab1jej times ! unit ( me*anical =ce1 t is to say1 #ab1jej times ! =ce t w\ld raise a p\nd ( matt] to ! height ( "o foot1 :5ce "s idea may be =m$ ( ! va/ am\nt ( =ce ex]t$ by ! sun's light )9 ! limits ( ! :ole t]re/rial atmosph]e4 7,n4 #bbc47 ,! dynamic en]gy ( ! undulations ( ! sol> light gives ! leaves ( plants ! p[] ( decompos+ c>bonic acid1 & ( sep>at+ ! p>ticles ( c>bon & hydrog5 f ! oxyg5 = :i* !y h s /rong an aff9ity4 ,9 ?is op]ation ! undulations ( ! sunbeam are ext+ui%$ z light & heat1 & ,pr(essor ,w4 ,?omson has prov$ t ! quantity ( ^! undulations ?us ext+ui%$ is precisely equal to ! pot5tial or quiesc5t en]gy ?us creat$1 & t precisely t v quantity ( light & heat is re/or$ :5 ! plants are burn$1 :atev] /ate !y may be 92 & t ?us1 z ,mr4 ,george ,/eph5son#ad has truly & beautifully obs]v$1 our coal fires & gas lamps re/ore to our use ! light & heat ( ! sun ( ! e>ly geological epo*s :i* h re/$ z dormant p[]s "u ! seas & m\nta9s = unnumb]$ ages4 ,! sun is !re=e ! s\rce ( ! me*anical en]gy ( all ! heat & motion ( inanimate ?+s1 ( all ! motions ( ! heat & light ( fires & artificial flames1 & ( ! heat ( all liv+ creatures4 ,= animal heat1 & weights rais$ or resi/ance ov]come1 are me*anical effects ( ! *emical comb9ation ( food ) oxyg52 & food is ei!r directly or indirectly vegetable1 consequ5tly dep5d5t ^u ! sun4 ,pr(essor ,helmholtz ( ,bonn has put 9 a /rong po9t ( view ! enorm\s /ore ( =ce possess$ by our sy/em by comp>+ x ) its equival5t ( heat4 ,! =ce ) :i* ! e>? moves 9 its orbit is su*1 t if br\ght to re/ by a sudd5 %ock1 a quantity ( heat w\ld be g5]at$ by ! bl[ equal to t produc$ by ! combu/ion ( f\rte5 su* e>?s ( solid coal2 & suppos+ ! capacity ( ! e>? = heat z l[ z t ( wat]1 ! globe w\ld be heat$ to #aa1bjj ,c5t4 ,x w\ld be q fus$ & = ! mo/ "p r$uc$ to vap\r4 ,if x %\ld fall to ! sun1 :i* x w\ld c]ta9ly d1 ! quantity ( heat develop$ by ! %ock w\ld be f\r hundr$ times z great4 ,! application ( heat to ! v>i\s bran*es ( ! me*anical & *emical arts has )9 ! pres5t c5tury effect$ a great] *ange 9 ! condition ( man ?an _h be5 accompli%$ 9 any equal p]iod ( 8 exi/5ce4 ,arm$ by ! expansion & cond5sation ( fluids ) a p[] equal to t ( ! lightn+ itself1 conqu]+ "t & space1 he flies ov] pla9s1 & travels on pa?s cut by human indu/ry ev5 ?r\gh m\nta9s ) a velocity & smoo?ness m l planet>y ?an t]re/rial motion2 he crosses ! deep 9 opposition to w9d & tide2 by releas+ ! /ra9 on ! cable1 he rides at an*or fe>less ( ! /orm2 he makes ! lightn+ 8 mess5g]2 & l a magician he raises f ! gloomy abyss ( ! m9e ! sunbeam ( =m] ages to dispel ! midnight d>kness4 ,! pr9cipal ph5om5a ( heat may be illu/rat$ by a comp>ison ) ^? ( s\nd4 ,_! excitation is n only simil> b id5tical1 z 9 friction & p]cussion2 !y are bo? communicat$ by contact & radiation2 & ,dr4 ,"y obs]ves t ! effect ( radiant heat 9 rais+ ! temp]ature ( a body ^u :i* x falls1 resembles ! sympa!tic agitation ( a /r+ :5 ! s\nd ( ano!r /r+ :i* is 9 unison ) x is transmitt$ ?r\gh ! air4 ,light1 heat1 s\nd1 & ! waves ( fluids are all subject to ! same laws2 _! undulatory !ories are p]fectly simil>3 h5ce ! int]f]5ce ( two hot rays mu/ produce cold1 t is1 !y mu/ ext+ui% "o ano!r3 d>kness results f ! int]f]5ce ( two undulations ( light1 sil5ce ensues f ! int]f]5ce ( two undulations ( s\nd1 & /ill wat] or no tide is ! consequ5ce ( ! int]f]5ce ( two tides4 ,! propagation ( s\nd1 h[ev]1 requires a mu* d5s] m$ium ?an t ( light & heat2 its int5sity dim9i%es z ! r>ity ( ! air increases3 s t1 at a v small height above ! surface ( ! e>?1 ! noise ( ! tempe/ ceases1 & ! ?und] is he>d no m 9 ^? b\ndless regions :]e ! heav5ly bodies accompli% _! p]iods 9 et]nal & sublime sil5ce4 ,a consci\sness ( ! fallacy ( our s5ses is "o ( ! mo/ important consequ5ces ( ! /udy ( nature4 ,?is /udy tea*es u t no object is se5 by u 9 its true place1 ow+ to ab]ration2 t ! col\rs ( sub/ances are solely ! effects ( ! action ( matt] ^u light2 & t light itself z well z heat & s\nd are n real be+s1 b m]e motions communicat$ to our p]ceptions by ! n]ves4 ,! human frame may !re=e be reg>d$ z an ela/ic sy/em1 ! diff]5t p>ts ( :i* are capable ( receiv+ ! tremors ( ela/ic m$ia1 & ( vibrat+ 9 unison ) any numb] ( sup]impos$ undulations1 all ( :i* h _! p]fect & indep5d5t effect4 ,"h our k ends3 ! my/]i\s influ5ce ( matt] on m9d w 9 all probability be = ev] hid f man4 ,,section ,,xxviii4 ,common or ,/atic ,electricity1 or ,electricity ( ,t5sion--,a ,dual ,p[]--,me?ods ( excit+ x--,attraction & ,repulsion--,conduction--,electrics & ,non-electrics--,induction--,dielectrics --,t5sion--,law ( ! ,electric ,=ce--,di/ribution--,laws ( ,di/ribution--,heat ( ,electricity--,electrical ,light & its ,spectrum--,velocity--,atmosph]ic ,electricity--,its cause--,electric ,cl\ds--,viol5t effects ( ,lightn+--,back ,/roke--,electric ,gl[--,phosphoresc5ce4 ,,electricity is a dual p[] :i* gives no visible sign ( its exi/5ce :5 9 equilibrio1 b :5 elicit$ =ces are develop$ capable ( produc+ ! mo/ sudd51 viol5t1 & de/ructive effects 9 "s cases1 :ile 9 o!rs _! action1 ?\gh g5]ally less en]getic1 is ( indef9ite & un9t]rupt$ cont9uance4 ,^! modifications ( ! electric =ces1 incid5tally dep5d+ ^u ! mann] 9 :i* !y are excit$1 pres5t ph5om5a ( great div]sity1 b yet s connect$ z to ju/ify ! conclusion t !y orig9ate 9 a common pr9ciple4 ,! hypo!sis ( electricity be+ a fluid is unt5able 9 ! pres5t advanc$ /ate ( ! sci5ce2 we only "k t x is a =ce ^: action is tw(old2 t bodies 9 "o electric /ate attract1 & 9 ano!r repel ea* o!r2 9 ! =m] ! electricity is said to be positive1 9 ! latt] negative2 & ?us reg>d+ x z a =ce1 its modes ( action come "u ! laws ( me*anics & ma!matical analysis4 ,electricity may be call$ into activity by ! friction ( het]og5e\s sub/ances1 z 9 ! common electrify+ ma*9e1 by me*anical p[]1 heat1 *emical action1 & ! influ5ce ( magnetism4 ,we are totally ignorant :y x is r\s$ f its neutral /ate by ^! means1 or ( ! mann] ( its exi/5ce 9 bodies2 b :5 excit$ x seems to produce a molecul> pol>ity or *emical *ange 9 ! ultimate p>ticles ( matt]4 ,! sci5ce is divid$ into v>i\s bran*es1 ( :i* /atic or common electricity comes fir/ "u consid]ation1 includ+ t ( ! atmosph]e4 ,sub/ances 9 a neutral /ate nei!r attract nor repel4 ,!re is a num]\s class call$ electrics 9 :i* ! electric equilibrium is de/roy$ by friction2 !n ! positive & negative electricities are call$ into action or sep>at$2 ! positive is impell$ 9 "o direction1 & ! negative 9 ano!r4 ,electricities ( ! same k9d repel1 :]eas ^? ( diff]5t k9ds attract ea* o!r4 ,! attractive p[] is exactly equal to ! repulsive p[] at equal di/ances1 & :5 n oppos$ !y coalesce ) great rapidity & viol5ce1 produc+ ! electric fla%1 explosion1 & %ock2 !n ! equilibrium is re/or$4 ,"o k9d ( electricity _c be evolv$ )\t ! evolution ( an equal quantity ( ! opposite k9d4 ,?us :5 a glass rod is rubb$ ) a piece ( silk1 z mu* positive electricity is elicit$ 9 ! glass z !re is negative 9 ! silk4 ,! k9d ( electricity dep5ds m ^u ! me*anical condition ?an on ! nature ( ! surface2 = :5 two plates ( glass1 "o poli%$ & ! o!r r\gh1 are rubb$ aga9/ ea* o!r1 ! poli%$ surface acquires positive & ! r\gh negative electricity4 ,! mann] 9 :i* friction is p]=m$ also alt]s ! k9d ( electricity4 ,equal l5g?s ( black & :ite ribbon appli$ longitud9ally to "o ano!r1 & drawn betwe5 ! f+] & ?umb s z to rub _! surfaces toge!r1 become electric4 ,:5 sep>at$ ! :ite ribbon is f\nd to h acquir$ positive electricity1 & ! black negative2 b if ! :ole l5g? ( ! black ribbon be drawn across ! bread? ( ! :ite1 ! black w be positively & ! :ite negatively electric :5 sep>at$4 ,! friction ( ! rubb] on ! glass plate ( ! electrify+ ma*9e produces abundance ( /atic electricity4 ,! friction ( ! /eam on ! valve ( an insulat$ locomotive /eam-eng9e produces sev5 times ! quantity ( electricity t an electrify+ ma*9e w\ld d ) a plate ?ree feet 9 diamet]1 work$ at ! rate ( #gj revolutions 9 a m9ute4 ,pressure is a s\rce ( electricity :i* ,m4 ,becqu]el has f\nd to be common to all bodies2 b x is necess>y to sep>ate !m to prev5t ! reunion ( ! electricities4 ,:5 two sub/ances ( any k9d :atev] are insulat$ & press$ toge!r !y assume diff]5t electric /ates1 b !y only %[ contr>y electricities :5 "o ( !m is a good conductor4 ,:5 bo? are good conductors !y mu/ be sep>at$ ) extreme rapidity to prev5t a return to equilibrium4 ,:5 ! sep>ation is v sudd5 ! t5sion ( ! two electricities may be great en\gh to produce light4 ,m4 ,becqu]el attributes ! light produc$ by ! collision ( iceb]gs to ?is cause4 ,icel& sp> is made electric by ! smalle/ pressure betwe5 ! f+] & ! ?umb1 & reta9s x = a long "t4 ,all ^! circum/ances are modifi$ by ! temp]ature ( ! sub/ances1 ! /ate ( _! surfaces & t ( ! atmosph]e4 ,sev]al cry/all9e bodies become electric :5 heat$1 especially t\rmal9e1 "o end ( :i* acquires positive1 & ! o!r negative electricity1 :ile ! int]m$iate "p is neutral4 ,if ! t\rmal9e be brok5 ?r\gh ! middle1 ea* fragm5t is f\nd to possess positive electricity at "o end & negative at ! o!r4 ,electricity is evolv$ by sub/ances pass+ f a liquid to a solid /ate1 & by *emical action dur+ ! production & cond5sation ( vap\r1 :i* is a great s\rce ( atmosph]ic electricity4 ,9 %ort1 x may be g5]ally /at$1 t :5 any cause :atev] t5ds to de/roy molecul> attraction !re is a developm5t ( electricity2 if1 h[ev]1 ! sub/ances be n imm$iately sep>at$1 !re w be an in/antane\s re/oration ( equilibrium4 ,electricity may be transf]r$ f "o body to ano!r 9 ! same mann] z heat is communicat$1 & l x too ! body loses by ! transmission4 ,al?\gh no sub/ance is altoge!r imp]vi\s to electricity1 nor is !re any t does n (f] "s resi/ance to its passage1 yet x moves ) m facility ?r\gh a c]ta9 class ( sub/ances call$ conductors1 su* z metals1 wat]1 ! human body1 c41 ?an ?r\gh atmosph]ic air1 glass1 silk1 c41 :i* are !re=e call$ non-conductors4 ,! conduct+ p[] is affect$ bo? by temp]ature & moi/ure4 ,! t]re/rial globe is a conductor on acc\nt ( its moi/ure1 ?\gh dry e>? is n4 ,?\gh metals are ! be/ conductors ( electricity1 x affects _! molecul> /ructure1 = ! heat :i* accompanies its passage acts z a transv]se expansive =ce1 :i* increases _! bread? by dim9i%+ _! l5g?1 z may be se5 by pass+ electricity ?r\gh a plat9um wire suffici5tly ?ick to resi/ fusion4 ,?r\gh air ! =ce is disruptive on acc\nt ( its non-conduct+ quality1 & x seems to act *emically on ! oxyg51 produc+ ! sub/ance kn[n z ozone dur+ its passage ?r\gh ! atmosph]e4 ,if a conductor be good & ( suffici5t size ! electricity passes imp]ceptibly b x is %iv]$ to pieces 9 an in/ant if x be a bad conductor or too small to c>ry (f ! *>ge4 ,9 t case ! physical *ange is g5]ally a sep>ation ( ! p>ticles1 or expansion f ! heat1 z 9 trees1 :]e x turns ! moi/ure into /eam1 b all ^! effects are 9 proportion to ! ob/acles oppos$ to ! fre$om ( its c\rse4 ,bodies surr\nd$ by non-conductors are said to be insulat$1 because :5 *>g$ ! electricity _c escape4 ,:5 t is n ! case1 ! electricity is convey$ to ! e>?3 consequ5tly x is impossible to accumulate electricity 9 a conduct+ sub/ance t is n insulat$4 ,!re are a great _m sub/ances call$ non-electrics 9 :i* electricity is n s5sibly develop$ by friction unless !y be insulat$1 because x is c>ri$ (f by _! conduct+ p[] z soon z elicit$4 ,metals1 = example1 :i* are said to be non-electrics c be excit$1 b be+ conductors !y _c reta9 ?is /ate if 9 communication ) ! e>?4 ,x is probable t no bodies exi/ :i* are ei!r p]fect non-electrics or p]fect non-conductors4 ,b x is evid5t t electrics mu/ be non-conductors to a c]ta9 degree1 o!rwise !y c\ld n reta9 _! electric /ate4 ,a body *>g$ ) electricity1 al?\gh p]fectly insulat$1 s t all escape ( electricity is prev5t$1 t5ds to produce an electric /ate ( ! opposite k9d 9 all bodies 9 its vic9ity4 ,positive electricity t5ds to produce negative electricity 9 a body ne> to x1 & vice v]s1 ! effect be+ great] z ! di/ance dim9i%es4 ,?is p[] :i* electricity possesses ( caus+ an opposite electrical /ate 9 its vic9ity is call$ induction4 ,a ,leyd5 j>1 = example1 or glass j> coat$ half way up bo? outside & 9 ) t9 foil1 :5 *>g$ ) positive electricity1 imm$iately induces negative electricity on ! t9 foil outside4 ,not)/&+ _! /rong mutual attraction !y are prev5t$ f coalesc+ by ! glass1 :i* is a non-conductor2 b if ! t9 inside & out be connect$ by a conduct+ wire !y in/antly unite4 ,:5 a body 9 ei!r electric /ate is pres5t$ to a neutral "o1 its t5d5cy 9 consequ5ce ( ! law ( induction is to di/urb ! condition ( ! neutral body by induc+ electricity contr>y to its own 9 ! adjac5t side1 & !re=e an electrical /ate simil> to its own 9 ! remote "p4 ,h5ce ! neutrality ( ! second body is de/roy$ by ! action ( ! fir/1 & ! adjac5t p>ts ( ! two1 hav+ n[ opposite electricities1 w attract ea* o!r4 ,! attraction betwe5 electrifi$ & unelectrifi$ sub/ances is a consequ5ce ( ! alt]$ /ate ( _! molecules4 ,induction dep5ds ^u ! facility ) :i* ! equilibrium ( ! neutral body c be ov]come1 a facility :i* is proportional to its conduct+ p[]4 ,consequ5tly ! attraction ex]t$ by an electrifi$ sub/ance ^u ano!r sub/ance previ\sly neutral w be mu* m en]getic if ! latt] be a conductor ?an if x be a non-conductor4 ,x is cle> t "o body _c act ^u ano!r at a di/ance )\t "s means ( communication4 ,dr4 ,f>aday has prov$ t ! int]v5+ non-conduct+ sub/ance or dielectric has a great influ5ce ^u induction4 ,?us ! inductive =ce is great] :5 sulphur is int]pos$ betwe5 ! two bodies ?an :5 %ellac is ! dielectric1 & great] :5 %ellac is ! dielectric ?an glass1 c4 ,pr(essor ,matteucci has prov$ by ! foll[+ exp]im5t t ! int]v5+ sub/ance is itself pol>iz$ by induction4 ,a numb] ( plates ( mica 9 contact 7 plac$ betwe5 two plates ( metal1 "o ( :i* 0 electrifi$1 s t ! :ole 0 *>g$ l a ,leyd5 j>4 ,on sep>at+ ! plates ) insulat+ h&les1 ea* plate ( mica 0 electrifi$2 "o side ( x 0 positive & ! o!r negative1 %[+ decid$ly a pol>ization by induction ?r\gh\t ! :ole int]v5+ non-conduct+ sub/ance2 & ?us1 al?\gh ! int]pos$ sub/ance or dielectric is incapable ( conduct+ ! electrical =ce f "o body to ! o!r1 x becomes by induction capable ( transmitt+ x4 ,9 ! atmosph]e induction is transmitt$ by t ( ! int]v5+ /rata ( air4 ,x is true t induction takes place ?r\gh ! mo/ p]fect vacuum we c make1 b !re always rema9s "s highly ela/ic air2 & ev5 if air c\ld be altoge!r exclud$1 ! e!real m$ium _c1 & x mu/ be capable ( induction1 s9ce1 h[ev] att5uat$1 x mu/ consi/ ( mat]ial atoms1 o!rwise x w\ld be a non5tity4 ,! law ( electrical attraction & repulsion has be5 det]m9$ by susp5d+ a ne$le ( gum-lac horizontally by a silk fibre1 ! ne$le c>ry+ at "o end a piece ( electrifi$ gold leaf4 ,a globe 9 ! same or opposite electrical /ate :5 pres5t$ to ! gold leaf w repel or attract x1 & w !re=e cause ! ne$le to vibrate m or less rapidly accord+ to ! di/ance ( ! globe4 ,a comp>ison ( ! numb] ( oscillations p]=m$ 9 a giv5 "t at diff]5t di/ances w det]m9e ! law ( ! v>iation ( ! electrical int5sity1 9 ! same mann] t ! =ce ( gravitation is measur$ by ! oscillations ( ! p5dulum4 ,c\lomb inv5t$ an in/rum5t :i* balances ! =ces 9 "q by ! =ce ( ! torsion ( a ?read1 :i* consequ5tly measures ! int5sity2 & ,sir ,william ,sn[ ,h>ris has con/ruct$ an in/rum5t ) :i* he has measur$ ! int5sity ( ! electrical =ce 9 t]ms ( ! weight requisite to balance x4 ,by ^! me?ods x has be5 f\nd t ! int5sity ( electrical attraction & repulsion v>ies inv]sely z ! squ>e ( ! di/ance4 ,h[ev]1 ! law ( repulsive =ce is liable to great di/urbances f inductive action1 :i* ,sir ,william ,sn[ ,h>ris has f\nd to exi/ n only betwe5 a *>g$ & neutral body1 b also betwe5 bodies simil>ly *>g$2 & t1 9 ! latt] case1 ! inductive process may be indef9itely modifi$ by ! v>i\s circum/ances ( ! quantity & int5sity ( ! electricity & ! di/ance betwe5 ! *>g$ bodies4 ,! quantity ( electricity bodies are capable ( receiv+ does n foll[ ! proportion ( _! bulk1 b dep5ds pr9cipally ^u ! =m & ext5t ( _! surface4 ,x appe>s f ! exp]im5ts ( ,sir ,w4 ,s4 ,h>ris t a giv5 quantity ( electricity1 divid$ betwe5 two p]fectly equal & simil> bodies1 ex]ts ^u ext]nal bodies only "o f\r? ( ! attractive =ce app>5t :5 dispos$ ^u "o ( !m2 & if x be di/ribut$ among ?ree equal & simil> bodies1 ! =ce is "o n9? ( t app>5t :5 x is dispos$ on "o ( !m4 ,h5ce1 if ! quantity ( electricity be ! same1 ! =ce v>ies inv]sely z ! squ>e ( ! surface on :i* x is dispos$2 & if ! surface be ! same1 ! =ce v>ies directly z ! squ>e ( ! quantity ( electricity4 ,^! laws h[ev] d n hold :5 ! =m ( ! surface is *ang$4 ,a giv5 quantity ( electricity dispos$ on a giv5 surface has ! greate/ int5sity :5 ! surface has a circul> =m1 & ! lea/ int5sity :5 ! surface is exp&$ into an indef9ite /raight l9e4 ,! decrease ( int5sity seems to arise f "s peculi> arrangem5t ( ! electricity dep5d+ on ! ext5sion ( ! surface4 ,x is q indep5d5t ( ! ext5t ( ! edge1 ! area be+ ! same2 = ,sir ,w4 ,s4 ,h>ris f\nd t ! electrical int5sity ( a *>g$ sph]e is ! same ) t ( a plane circul> area ( ! same sup]ficial ext5t1 & t ( a *>g$ cyl9d] ! same z if x 7 cut op5 & exp&$ into a plane surface4 ,! same able electrician has %[n t ! attractive =ce betwe5 an electrifi$ & a neutral un9sulat$ body is ! same :atev] be ! =ms ( _! unoppos$ p>ts4 ,?us two hemisph]es attract ea* o!r ) precisely ! same =ce z if !y 7 sph]es2 & z ! =ce is z ! numb] ( attract+ po9ts 9 op]ation directly1 & z ! squ>es ( ! respective di/ances inv]sely1 x foll[s t ! attraction betwe5 a m]e r+ & a circul> area is no great] ?an t betwe5 two simil> r+s1 & ! =ce betwe5 a sph]e & an oppos$ sph]ical segm5t ( ! same curvature is no great] ?an t ( two simil> segm5ts1 ea* equal to ! giv5 segm5t4 ,electricity may be accumulat$ to a great ext5t 9 insulat$ bodies1 & s long z x is quiesc5t x occasions no s5sible *ange 9 _! prop]ties4 ,:5 re/ra9$ by ! non-conduct+ p[] ( ! atmosph]e1 its t5sion or ! pressure x ex]ts is proportional to ! co]cive =ce ( ! air4 ,if ! pressure be less ?an ! co]cive =ce1 ! electricity is reta9$2 b ! in/ant x exce$s t =ce 9 any "o po9t x escapes1 & t m readily :5 ! air is att5uat$ or saturat$ ) moi/ure1 = ! resi/ance ( ! air is proportional to ! squ>e ( its d5sity1 b ! inductive action ( electricity on di/ant bodies is indep5d5t ( atmosph]ic pressure4 ,! p[] ( reta9+ electricity dep5ds also on ! %ape ( ! *>g$ body4 ,x is mo/ easily reta9$ by a sph]e1 next to t by a sph]oid1 b x readily escapes f a po9t1 & a po9t$ object receives x ) mo/ facility4 ,! heat produc$ by ! electric %ock is proportional to ! squ>e ( ! quantity ( electricity dis*>g$1 & is s int5se t x fuses metals & volatilizes sub/ances1 b its int5sity is n felt to its full ext5t on acc\nt ( ! %ortness ( its duration4 ,x is only accompani$ by light :5 ! electricity is ob/ruct$ 9 its passage ?r\gh sub/ance4 ,electrical light :5 analys$ by a prism diff]s v mu* f sol> light4 ,fraunh(] f\nd t1 in/ead ( ! fix$ d>k l9es1 ! spectrum ( an electric sp>k is cross$ by num]\s bright l9es2 & ,pr(essor ,:eat/one has obs]v$ t ! numb] & position ( ! l9es diff] ) ! metal f :i* ! sp>k is tak51 & believes ! sp>k itself results f ! ignition & volatilization ( ! matt] ( ! conductor4 ,accord+ to ! exp]im5ts ( ,sir ,humphry ,davy1 ! d5sity ( ! air has an influ5ce on ! col\r4 ,he pass$ ! electric sp>k ?r\gh a vacuum ov] m]cury1 :i* f gre5 became successively sea-gre51 blue1 & purple1 on admitt+ diff]5t quantities ( air4 ,:5 ! vacuum 0 made ov] a fusible alloy ( t9 & bismu?1 ! sp>k 0 yell[i% & extremely pale4 ,sir ,humphry !nce conclud$ t electrical light pr9cipally dep5ds ^u "s prop]ties belong+ to ! pond]able matt] ?r\gh :i* x passes1 & t space is capable ( exhibit+ lum9\s appe>ances1 ?\gh x does n conta9 an appreciable quantity ( matt]4 ,he ?\ght t ! sup]ficial p>ticles ( bodies :i* =m vap\r1 :5 deta*$ by ! repulsive p[] ( heat1 might be equally sep>at$ by ! electric =ces1 & produce lum9\s appe>ances 9 vacuo by ! de/ruction ( _! opposite electric /ates4 ,! velocity ( electricity is s great t ! mo/ rapid motion :i* c be produc$ by art appe>s to be actual re/ :5 comp>$ ) x4 ,a :eel revolv+ ) cel]ity suffici5t to r5d] its spokes invisible1 :5 illum9at$ by a fla% ( lightn+1 is se5 = an in/ant ) all its spokes di/9ct1 z if x 7 9 a /ate ( absolute repose2 because1 h[ev] rapid ! rotation may be1 ! light has come & already ceas$ be=e ! :eel has _h "t to turn ?r\gh a s5sible space4 ,?is beautiful exp]im5t is due to ,pr(essor ,:eat/one1 z well z ! foll[+ v>iation ( x1 :i* is n less /rik+3 ,if a circul> piece ( pa/ebo>d be divid$ into ?ree sectors1 "o ( :i* is pa9t$ blue1 ano!r yell[1 & a ?ird r$1 x w appe> to be :ite :5 revolv+ quickly1 because ( ! rapidity ) :i* ! impressions ( ! col\rs succe$ ea* o!r on ! ret9a4 ,b1 ! in/ant x is illum9at$ by an electric sp>k1 x seems to /& /ill1 & ea* col\r is z di/9ct z if x 7 at re/4 ,?is transc5d5t spe$ ( electricity has be5 +5i\sly measur$1 z foll[s1 by ,pr(essor ,:eat/one1 :o has asc]ta9$ t x mu* surpasses ! velocity ( light4 ,9 ! horizontal diamet] ( a small disc1 fix$ on ! wall ( a d>k5$ room1 are dispos$ six small brass balls1 well insulat$ f ea* o!r4 ,an insulat$ copp] wire1 half a mile long1 is disjo9t$ 9 its middle1 & also ne> its two extremities2 ! six ends ?us obta9$ are connect$ ) ! six-balls on ! disc4 ,:5 an electric dis*>ge is s5t ?r\gh ! wire by connect+ its two extremities1 "o ) ! positive1 & ! o!r ) ! negative coat+ ( a ,leyd5 j>1 ?ree sp>ks are se5 on ! disc1 app>5tly at ! same in/ant4 ,at ! di/ance ( ab\t t5 feet a small revolv+ mirror is plac$ s z to reflect ^! ?ree sp>ks dur+ its revolution4 ,f ! extreme velocity ( ! electricity1 x is cle> t1 if ! ?ree sp>ks be simultane\s1 !y w be reflect$1 & w vani% be=e ! mirror has s5sibly *ang$ its position1 h[ev] rapid its rotation may be1 & !y w be se5 9 a /raight l9e4 ,b if ! ?ree sp>ks be n simultane\sly transmitt$ to ! disc--if "o1 = example1 be lat] ?an ! o!r two--! mirror w h "t to revolve ?r\gh an indef9itely small arc 9 ! int]val betwe5 ! reflection ( ! two sp>ks & t ( ! s+le "o4 ,h[ev]1 ! only indication ( ?is small motion ( ! mirror w be1 t ! s+le sp>k w n be reflect$ 9 ! same /raight l9e ) ! o!r two1 b a little above or bel[ x1 = ! reflection ( all ?ree w /ill be app>5tly simultane\s1 ! "t int]v5+ be+ mu* too %ort to be appreciat$4 ,s9ce ! numb] ( revolutions :i* ! revolv+ mirror makes 9 a second is kn[n1 & ! angul> deviation ( ! reflection ( ! s+le sp>k f ! reflection ( ! o!r two c be measur$1 ! "t elaps$ betwe5 _! consecutive reflections c be asc]ta9$4 ,&1 z ! l5g? ( t "p ( ! wire ?r\gh :i* ! electricity has pass$ is giv51 its velocity may be f\nd4 ,! numb] ( pulses 9 a second1 requisite to produce a musical note ( any pit*1 are kn[n2 h5ce ! numb] ( revolutions accompli%$ by ! mirror 9 a giv5 "t may be det]m9$ f ! musical note produc$ by a too? or peg1 9 its axis ( rotation1 /rik+ aga9/ a c>d1 or f ! notes ( a sir5 atta*$ to ! axis4 ,x 0 ?us t ,pr(essor ,:eat/one f\nd ! mirror :i* he employ$ 9 8 exp]im5ts made #hjj revolutions 9 a second2 &1 z ! angul> velocity ( ! reflect$ image 9 a revolv+ mirror is d\ble t ( ! mirror itself1 an angul> deviation ( "o degree 9 ! appe>ance ( ! two sp>ks w\ld indicate an int]val ( ! #egf1jjj? ( a second2 ! deviation ( half a degree w\ld1 !re=e1 indicate m ?an ! million? ( a second4 ,! use ( s\nd z a measure ( velocity is a happy illu/ration ( ! connexion ( ! physical sci5ces4 ,! e>? possesses a p[]ful electrical t5sion1 & ! atmosph]e :5 cle> is almo/ always positively electric4 ,its electricity is /rong] 9 w9t] ?an 9 summ]1 dur+ ! day ?an 9 ! night4 ,! int5sity increases = two or ?ree h\rs f ! "t ( sunrise1 comes to a maximum betwe5 sev5 & eight1 !n decreases t[>ds ! middle ( ! day1 arrives at its m9imum betwe5 "o & two1 & aga9 augm5ts z ! sun decl9es till ab\t ! "t ( sunset1 aft] :i* x dim9i%es & cont9ues feeble dur+ ! night4 ,! m]e cond5sation ( vap\r is a s\rce ( atmosph]ic electricity2 b al?\gh x is also produc$ by ! vap\r t rises f ! surface ( ! e>?1 x is n "u all circum/ances4 ,m4 ,p\illet f\nd t electricity is only develop$ :5 accompani$ by *emical action3 = example1 :5 ! wat] :5ce ! vap\r proce$s conta9s lime1 *alk1 or any solid alkali1 negative electricity is produc$2 & :5 x holds 9 solution ei!r gas1 acid1 or "s ( ! salts1 ! vap\r is positively electric4 ,besides1 ! contact ( e>? ) salt & fre% wat] g5]ates positive electricity1 & ! contact ( fre% & salt curr5ts ( wat] negative1 s t ! ocean mu/ af=d a great supply to ! atmosph]e2 h5ce ?und]/orms are mo/ frequ5t ne> ! coa/s3 b z electricity ( "o k9d or ano!r is develop$ :5ev] ! molecules ( matt] are d]ang$ f _! natural /ate ( equilibrium1 !re mu/ be _m p>tial v>iations 9 ! electric /ate ( ! air4 ,:5 ! invisible vap\r rises *>g$ ) electricity into ! cold regions ( ! atmosph]e1 x is cond5s$ into cl\d1 9 :i* ! t5sion is increas$ because ! electricity is conf9$ to a small] space2 & if ! cond5sation be suffici5t to produce drops ( ra91 !y c>ry ! electricity to ! gr\nd1 s t 9 g5]al a %[] is a conductor betwe5 ! cl\ds & ! e>?4 ,:5 two cl\ds *>g$ ) opposite k9ds1 b ( equal t5sion1 approa* )9 a c]ta9 di/ance1 ! int5sity increases on ! sides ( ! cl\ds t are ne>e/ to "o ano!r2 & :5 ! t5sion is great en\gh to ov]come ! co]cive pressure ( ! atmosph]e1 a dis*>ge takes place :i* causes a fla% ( lightn+1 ! /roke be+ giv5 ei!r by ! cl\d or ! ra94 ,! actual quantity ( electricity 9 any "p ( a cl\d is extremely small4 ,! int5sity ( ! fla% arises f ! great ext5t ( surface ov] :i* x is spread1 s t cl\ds may be comp>$ to enorm\s ,leyd5 j>s ?9ly coat$ ) electricity1 :i* only acquires its int5sity by its in/antane\s cond5sation4 ,! rapid & irregul> motions ( ?und] cl\ds are probably m ow+ to /rong electrical attractions & repulsions among !mselves ?an to curr5ts ( air1 ?\gh bo? are no d\bt conc]n$ 9 ^! ho/ile movem5ts4 ,! atmosph]e becomes int5sely electric on ! approa* ( ra91 hail1 sn[1 sleet1 & w9d2 b x v>ies aft]w>ds1 & ! transitions are v rapid on ! approa* ( a ?und]/orm4 ,s9ce air is a non-conductor1 x does n convey ! electricity f ! cl\ds to ! e>?1 b x acquires f !m an opposite k9d1 & :5 ! t5sion is v great ! =ce ( ! electricity becomes irresi/ible1 & an int]*ange takes place betwe5 ! cl\ds & ! e>?2 b s rapid is ! motion ( lightn+1 t x is difficult to asc]ta9 :e!r x goes f ! cl\ds to ! e>? or %oots upw>ds f ! e>? to ! cl\ds1 ?\gh !re c be no d\bt t x does bo?4 ,9 a /orm t occurr$ at ,man*e/] 9 ,june #ahce1 ! lightn+ 0 obs]v$ to issue f v>i\s po9ts ( a road1 att5d$ by explosions z if pi/ols _h be5 fir$ out ( ! gr\nd1 & a man seems to h be5 kill$ by "o ( ^! explosions tak+ place "u 8 foot4 ,m4 ,gay ,lussac asc]ta9$ t a fla% ( lightn+ sometimes d>ts m ?an ?ree miles 9 a /raight l9e4 ,a p]son may be kill$ by lightn+1 al?\gh ! explosion takes place at a di/ance ( tw5ty miles1 by :at is call$ ! back /roke4 ,suppose t ! two extremities ( a highly *>g$ cl\d hang d[n t[>ds ! e>?1 !y w repel ! electricity f ! e>?'s surface if x be ( ! same k9d ) _! own1 & w attract ! o!r k9d2 & if a dis*>ge %\ld sudd5ly take place at "o end ( ! cl\d1 ! equilibrium w be in/antly re/or$ by a fla% at t po9t ( ! e>? :i* is "u ! o!r4 ,?\gh ! back /roke is (t5 suffici5tly p[]ful to de/roy life1 x is nev] s t]rible 9 its effects z ! direct /roke1 :i* is (t5 ( inconceivable int5sity4 ,in/ances h occurr$ :5 l>ge masses ( iron & /one1 & ev5 _m feet ( a /one wall1 h be5 c>ri$ to a consid]able di/ance by a /roke ( lightn+4 ,rocks & ! tops ( m\nta9s (t5 be> ! m>ks ( fusion f its int5se heat2 & occasionally vitre\s tubes desc5d+ _m feet into banks ( s& m>k its pa?4 ,dr4 ,fi$l] exhibit$ sev]al ( ^! fulgorites 9 ,london ( consid]able l5g?1 :i* _h be5 dug out ( ! s&y pla9s ( ,silesia & ,ea/]n ,prussia4 ,"o f\nd at ,pad]born 0 =ty feet long4 ,_! ramifications g5]ally t]m9ate 9 pools or spr+s ( wat] bel[ ! s&1 :i* are suppos$ to det]m9e ! c\rse ( ! lightn+4 ,no d\bt ! soil & sub/rata mu/ influ5ce its direction1 s9ce x is f\nd by exp]i5ce t places :i* h be5 once /ruck by lightn+ are (t5 /ruck aga94 ,an insulat$ conductor on ! approa* ( a /orm gives out su* quantities ( sp>ks t x is dang]\s to approa* x1 z 0 fatally exp]i5c$ by ,pr(essor ,ri*man at ,pet]sburg1 :o 0 /ruck dead by a globe ( fire f ! extremity ( a conductor1 :ile mak+ exp]im5ts on atmosph]ic electricity4 ,copp] conductors af=d ! be/ protection1 especially if !y expose a broad surface1 s9ce electricity is convey$ along ! surface ( bodies4 ,!re is no in/ance ( an electric cl\d ( high t5sion be+ dispell$ by a conductor1 yet ^? inv5t$ by ,sir ,william ,sn[ ,h>ris1 & univ]sally employ$ 9 ! navy1 af=d a complete protection 9 ! mo/ imm95t dang]4 ,! ,%annon1 a #ej-;gun frigate1 comm&$ by ! brave & lam5t$ ,sir ,william ,peel1 0 envelop$ 9 a ?und]-/orm :5 ab\t #ij miles to ! nor?-we/ ( ,java4 ,x began at fifty m9utes pa/ f\r 9 ! aft]noon2 ! %ip 0 driv5 be=e ! /orm1 9 a high sea1 amid /reams ( vivid lightn+1 deaf5+ ?und]1 hail1 & ra94 ,at five o'clock an imm5se ball ( fire cov]$ ! ma9topgallant ma/1 ran up ! royal pole1 & explod$ 9 ! air ) a t]rific concussion1 cov]+ all ! surr\nd+ space ) sp>ks ( electric light1 :i* 7 driv5 rapidly to leew>d by ! w9d4 ,fifte5 m9utes lat] an imm5se mass ( lightn+ /ruck ! ma9ma/1 att5d$ by a viol5t gu/ ( w9d2 & ano!r heavy dis*>ge fell on x a qu>t] ( an h\r aft]w>ds4 ,f t "t till six o'clock ! %ip 0 cont9ually encompass$ by %>p =k$ lightn+1 accompani$ by incessant peals ( ?und]4 ,?\gh actually envelop$ 9 electricity1 & /ruck ?ree times1 nei!r ! hull nor ! rigg+ su/a9$ ! slighte/ injury4 ,:5 ! air is r>efi$ by heat1 its co]cive p[] is dim9i%$1 s t ! electricity escapes f ! cl\ds 9 ^? lamb5t diffuse fla%es )\t ?und] s frequ5t 9 w>m summ] ev5+s2 & :5 ! atmosph]e is highly *>g$ ) electricity1 x n unfrequ5tly happ5s t electric light1 9 ! =m ( a />1 is se5 on ! topma/s & y>d-arms ( %ips4 ,9 #ahca ! ,fr5* (fic]s at ,algi]s 7 surpris$ to see bru%es ( light on ! heads ( _! comrades1 & at ! po9ts ( _! f+]s :5 !y held up _! h&s4 ,?is ph5om5on 0 well kn[n to ! anci5ts1 :o reckon$ x a lucky om54 ,_m sub/ances1 9 decay+1 emit light1 :i* is attribut$ to electricity1 su* z fi% & rott5 wood4 ,oy/]-%ells1 & a v>iety ( m9]als1 become phosphoresc5t at c]ta9 temp]atures :5 expos$ to electric %ocks or friction3 inde$1 mo/ ( ! causes :i* di/urb molecul> equilibrium give rise to phosphoric ph5om5a4 ,! m9]als possess+ ?is prop]ty are g5]ally col\r$ or imp]fectly transp>5t2 &1 ?\gh ! col\r ( ?is light v>ies 9 diff]5t sub/ances1 x has no fix$ relation to ! col\r ( ! m9]al4 ,an int5se heat entirely de/roys ?is prop]ty1 & ! phosphoresc5t light develop$ by heat has no connexion ) light produc$ by friction2 = ,sir ,david ,brew/] obs]v$ t bodies depriv$ ( ! faculty ( emitt+ ! "o are /ill capable ( giv+ out ! o!r4 ,among ! bodies :i* g5]ally become phosphoresc5t :5 expos$ to heat1 !re are "s specim5s :i* d n possess ?is prop]ty2 :]e=e phosphoresc5ce _c be reg>d$ z an ess5tial "* ( ! m9]als possess+ x4 ,sulphuret ( calcium1 kn[n z ,canton's phosphorus1 & ! sulphuret ( b>ium1 or ,bologna /one1 possess ! phosphoresc5t prop]ty 9 an em95t degree4 ,multitudes ( fi% are end[$ ) ! p[] ( emitt+ light at pleasure1 no d\bt to enable !m to pursue _! prey at dep?s :]e ! sunbeams _c p5etrate4 ,fla%es ( light are frequ5tly se5 to d>t along a %oal ( h]r+s or pil*>ds2 & ! ,m$usa tribes are not$ = _! phosphoresc5t brilliancy1 _m ( :i* are extremely small1 & s num]\s z to make ! wake ( a vessel look l a /ream ( silv]4 ,nev]!less1 ! lum9\s appe>ance :i* is frequ5tly obs]v$ 9 ! sea dur+ ! summ] mon?s _c always be attribut$ to m>9e animalcul1 z ! foll[+ n>rative w %[3-- ,capta9 ,bonnyca/le1 com+ up ! ,gulf ( ,/4 ,lawr5ce on ! #g? ( ,septemb]1 #ahbf1 0 r\s$ by ! mate ( ! vessel 9 great al>m f an unusual appe>ance4 ,x 0 a />light night1 :5 sudd5ly ! sky became ov]ca/ 9 ! direction ( ! high l&1 & an in/antane\s & int5sely vivid light1 resembl+ ! aurora1 %ot out ( ! hi!rto gloomy & d>k sea on ! lee b[1 :i* 0 s brilliant t x light$ ev]y?+ di/9ctly ev5 to ! ma/-head4 ,! light spread ov] ! :ole sea betwe5 ! two %ores1 & ! waves1 :i* be=e _h be5 tranquil1 n[ began to be agitat$4 ,capta9 ,bonnyca/le describes ! sc5e z t ( a blaz+ %eet ( awful & mo/ brilliant light4 ,a long & vivid l9e ( light1 sup]ior 9 brightness to ! p>ts ( ! sea n imm$iately ne> ! vessel1 %[$ ! base ( ! high1 fr[n+1 & d>k l& abrea/2 ! sky became l[]+ & m int5sely obscure4 ,long tortu\s l9es ( light %[$ imm5se numb]s ( v l>ge fi% d>t+ ab\t z if 9 con/]nation4 ,! sprit-sail y>d & miz5-boom 7 light$ by ! gl>e1 z if gaslights _h be5 burn+ directly bel[ !m2 & until j be=e daybreak1 at f\r o'clock1 ! mo/ m9ute objects 7 di/9ctly visible4 ,day broke v sl[ly1 & ! sun rose ( a fi]y & ?reat5+ aspect4 ,ra9 foll[$4 ,capta9 ,bonnyca/le caus$ a bucket ( ?is fi]y wat] to be drawn up2 x 0 "o mass ( light :5 /irr$ by ! h&1 & n 9 sp>ks z usual1 b 9 actual coruscations4 ,a portion ( ! wat] pres]v$ its lum9osity = sev5 nights4 ,on ! ?ird night1 ! sc9tillations ( ! sea reappe>$2 ! sun w5t d[n v s+ul>ly1 exhibit+ 9 its desc5t a d\ble sun2 &1 :5 only a few degrees high1 its sph]ical figure *ang$ into t ( a long cyl9d]1 :i* rea*$ ! horizon4 ,9 ! night ! sea became ne>ly z lum9\s z be=e1 b on ! fif? night ! appe>ance entirely ceas$4 ,capta9 ,bonnyca/le did n ?9k x proce$$ f animalcul1 b imag9$ x might be "s comp\nd ( phosphorus1 sudd5ly evolv$ & dispos$ ov] ! surface ( ! sea4 ,x _h probably be5 t peculi> =m ( electricity kn[n z ! gl[ dis*>ge1 ( :i* ! au?or once saw a v rem>kable in/ance4 ,m4 ,e4 ,becqu]el assures u t almo/ all sub/ances are phosphoresc5t aft] be+ expos$ to ! sun if in/antly )drawn into d>kness1 & t x dep5ds ^u ! arrangem5t ( ! p>ticles & n ^u *emical action4 ,! salts ( uranium give ! same k9d ( phosphoresc5t light z t produc$ by ! violet rays ( ! sol> spectrum4 ,a solution ( ! bisulphate ( qu99e emits a yell[ phosphoresc5t light1 :]eas ! fluoresc5t light ( t liquid is blue4 ,! col\rs ( ^! two k9ds ( light are g5]ally complem5t>y to "o ano!r4 ,phosphoresc5ce is probably m or less conc]n$ 9 "s1 at lea/1 ( a s]ies ( v curi\s exp]im5ts made by ,m4 ,niepc de ,sa9t-,victor1 on :at he calls ! saturation ( sub/ances ) light4 ,x has long be5 kn[n t1 if a p]son 9 an int5sely d>k room %\ld expose 8 arm to ! sun ?r\gh a hole 9 a w9d[-%utt]1 x w %9e on be+ drawn into ! d>kness4 ,n[1 ,m4 de ,sa9t-,victor f\nd t if an engrav+ be expos$ = a c]ta9 "t to ! sun1 & in/antly br\ght into d>kness1 x w make a photographic impression on a collodion or arg5t9e surface1 & t any?+ writt5 or drawn ) t>t>ic acid1 or a solution ( ! salts ( uranium1 9 l>ge *>act]s1 is reproduc$ ev5 at a small di/ance f a s5sitive surface4 ,x may be presum$ t ! light communicates its vibrations to ! surfaces expos$ to x ) suffici5t =ce to enable !m to di/urb ! un/able equilibrium ( su* s5sitive sub/ances z collodion or ! arg5t9e salts4 ,m4 de ,sa9t-,victor has %[n t t>t>ic acid1 :i* is readily impress$ by sunlight1 is nei!r fluoresc5t nor phosphoresc5t1 :5ce he concludes t 8 exp]im5ts are indep5d5t ( bo? ( ^! modes ( action4 ,uranium appe>s to h v peculi> prop]ties3 its salts are /rongly lum9\s :5 expos$ to ! sun2 !y are v fluoresc5t2 & ! cry/alliz$ azitote ( uranium becomes phosphoresc5t by p]cussion4 ,,section ,,xxix4 ,voltaic ,electricity--,! ,voltaic ,batt]y--,int5sity--,quantity--,/atic ,electricity1 & ,electricity 9 ,motion--,lum9\s ,effects--,mr4 ,grove on ! ,electric ,arc & ,light--,decomposition ( ,wat]--,=mation ( ,cry/als by ,voltaic ,electricity--,photo-galvanic ,engrav+--,conduction--,heat ( ,voltaic ,electricity--,electric ,fi%4 ,,voltaic or ,dynamic electricity is elicit$ by ! =ce ( *emical action4 ,x is connect$ ) "s ( ! mo/ brilliant p]iods ( ,briti% sci5ce1 f ! spl5did discov]ies to :i* x l$ ,sir ,humphry ,davy & ,dr4 ,f>aday4 ,9 #agij1 :ile ,galvani1 ,pr(essor ( ,anatomy 9 ,bologna1 0 mak+ exp]im5ts on electricity1 he 0 surpris$ to see convulsive motions 9 ! limbs ( a dead frog accid5tally ly+ ne> ! ma*9e dur+ an electrical dis*>ge4 ,?\gh a simil> action _h be5 notic$ long be=e 8 "t1 he 0 s mu* /ruck ) ?is s+ul> ph5om5on1 t he exam9$ all ! circum/ances c>efully1 & at l5g? f\nd t convulsions take place :5 ! n]ve & muscle ( a frog are connect$ by a metallic conductor4 ,?is excit$ ! att5tion ( all ,europe2 & x 0 n long be=e ,volta1 ,pr(essor at ,pavia1 %[$ t ! m]e contact ( diff]5t bodies is suffici5t to di/urb electrical equilibrium1 & t a curr5t ( electricity fl[s 9 "o direction ?r\gh a circuit ( ?ree conduct+ sub/ances4 ,f ?is he 0 l$1 by acute reason+ & exp]im5t1 to ! con/ruction ( ! ,voltaic pile1 :i*1 9 its e>ly =m1 consi/$ ( alt]nate discs ( z9c & copp]1 sep>at$ by pieces ( wet clo?1 ! extremities be+ connect$ by wires4 ,?is simple app>atus1 p]haps ! mo/ wond]ful in/rum5t t has be5 inv5t$ by ! +5uity ( man1 by dive/+ electricity ( its sudd5 & uncontrollable viol5ce1 & giv+ 9 a cont9u$ /ream a great] quantity at a dim9i%$ int5sity1 has exhibit$ t =ce "u a new & manageable =m1 possess+ p[]s ! mo/ a/oni%+ & unexpect$4 ,! expression curr5t has no relation to a fluid1 :i* is n[ consid]$ to be z inconsi/5t ) ! ph5om5a ( dynamic z ) /atic electricity4 ,x 0 %[n by ,grot?us t ! transmission ( ,voltaic electricity ?r\gh liquids consi/s ( a s]ies ( *emical aff9ities act+ 9 def9ite directions2 & ,mr4 ,grove1 f an exam9ation ( its action on ! v>i\s k9ds ( matt]1 has come to ! same conclusion4 ,inde$ x is n[ ! g5]ally receiv$ op9ion t a curr5t ( electricity is m]ely a cont9u\s transmission ( *emical aff9ity f p>ticle to p>ticle ( ! sub/ance ?r\gh :i* x is pass+1 & consequ5tly t x is a cont9u\s transmission ( =ce4 ,z ! ,voltaic batt]y has become "o ( ! mo/ important eng9es ( physical rese>*1 "s acc\nt ( its pres5t condition may n be out ( place4 ,! di/urbance ( electric equilibrium1 & a developm5t ( electricity1 inv>iably accompany ! *emical action ( a fluid on metallic sub/ances1 & ! electricity is mo/ pl5tiful :5 t action occasions oxidation4 ,metals v>y 9 ! quantity ( electricity af=d$ by _! comb9ation ) oxyg54 ,b ! greate/ abundance is develop$ by ! oxidation ( z9c by weak sulphuric acid4 ,&1 9 con=mity ) ! law t "o k9d ( electricity _c be evolv$ )\t an equal quantity ( ! o!r be+ br\ght into activity1 x is f\nd t ! acid is positively1 & ! z9c negatively electric4 ,x has n yet be5 asc]ta9$ :y equilibrium is n re/or$ by ! contact ( ^! two sub/ances1 :i* are bo? conductors1 & 9 opposite electrical /ates4 ,h[ev]1 ! electrical & *emical *anges are s connect$1 t1 unless equilibrium be re/or$1 ! action ( ! acid w g on languidly1 or /op z soon z a c]ta9 quantity ( electricity is accumulat$ 9 x4 ,equilibrium1 nev]!less1 w be re/or$1 & ! action ( ! acid w be cont9u\s1 if a plate ( copp] be plac$ 9 contact ) ! z9c1 bo? be+ imm]s$ 9 ! fluid2 = ! copp]1 n be+ act$ ^u by ! acid1 w s]ve z a conductor to convey ! positive electricity f ! acid to ! z9c1 & w at e in/ant re/ore ! equilibrium1 & !n ! oxidation ( ! z9c w g on rapidly4 ,?us ?ree sub/ances are conc]n$ 9 =m+ a ,voltaic circuit1 b x is indisp5sable t "o ( !m %\ld be a fluid4 ,! electricity s obta9$ w be v feeble 9 ov]com+ resi/ances (f]$ by imp]fect conductors int]pos$ 9 ! circuit1 or by v long wires1 b x may be augm5t$ by increas+ ! numb] ( plates4 ,9 ! common ,voltaic batt]y1 ! electricity :i* ! fluid has acquir$ f ! fir/ plate ( z9c expos$ to its action is tak5 up by ! copp] plate belong+ to ! second pair1 & transf]r$ to ! second z9c plate1 ) :i* x is connect$4 ,! second plate ( z9c1 possess+ equal p[]s1 & act+ 9 con=mity ) ! fir/1 hav+ ?us acquir$ a l>g] portion ( electricity ?an its natural %>e1 communicates a l>g] quantity to ! fluid 9 ! second cell4 ,?is increas$ quantity is aga9 transf]r$ to ! next pair ( plates2 & ?us e succe$+ alt]nation is productive ( a fur!r increase 9 ! quantity ( ! electricity develop$4 ,?is action1 h[ev]1 w\ld /op unless a v5t 7 giv5 to ! accumulat$ electricity1 by e/abli%+ a communication betwe5 ! positive & negative poles ( ! batt]y by means ( wires atta*$ to ! extreme plate at ea* end4 ,:5 ! wires are br\ght into contact1 ! ,voltaic circuit is complet$1 ! electricities meet & neutralize ea* o!r1 produc+ ! %ock & o!r electrical ph5om5a2 & !n ! electric curr5t cont9ues to fl[ un9t]rupt$ly 9 ! circuit1 z long z ! *emical action la/s4 ,! /ream ( positive electricity fl[s f ! z9c to ! copp]4 ,! con/ruction & p[] ( ! ,voltaic batt]y h be5 mu* improv$ ( late ye>s1 b ! mo/ valuable improvem5t is ! con/ant batt]y ( ,pr(essor ,daniell4 ,9 all batt]ies ( ! ord9>y con/ruction1 ! p[]1 h[ev] en]getic at fir/1 rapidly dim9i%es1 & ultimately becomes v feeble4 ,pr(essor ,daniell f\nd t ?is dim9ution ( p[] is occasion$ by ! adhesion ( ! evolv$ hydrog5 to ! surface ( ! copp]1 & by ! precipitation ( ! sulphate =m$ by ! action ( ! acid on ! z9c4 ,he prev5ts ! latt] by int]pos+ betwe5 ! copp] & ! z9c1 9 ! cell conta9+ ! liquid1 a membrane :i*1 )\t imp$+ ! electric curr5t1 prev5ts ! transf] ( ! salt2 & ! =m]1 by plac+ betwe5 ! copp] & ! membrane solution ( sulphate ( copp]1 :i* be+ r$uc$ by ! hydrog5 prev5ts ! adhesion ( ?is gas to ! metallic surface4 ,ea* elem5t ( ! batt]y consi/s ( a holl[ cyl9d] ( copp]1 9 ! axis ( :i* is plac$ a cyl9drical rod ( z9c2 betwe5 ! z9c & ! copp] a membran\s bag is plac$1 :i* divides ! cell into two portions1 ! inn] ( :i* is fill$ ) dilute acid1 & ! "o ne>] ! copp] is suppli$ ) cry/als ( ! sulphate ( t metal4 ,! batt]y consi/s ( sev]al ( ^! elem5t>y cells connect$ toge!r by metallic wires1 ! z9c rod ( "o ) ! copp] cyl9d] ( t next to x4 ,! z9c rods are amalgamat$1 s t local action1 :i*1 9 ord9>y cases1 is s de/ructive ( ! z9c1 does n take place1 & no *emical action is manife/$ unless ! circuit be complet$4 ,! rods are easily deta*$1 & o!rs sub/itut$ = !m :5 worn out4 ,?is batt]y1 :i* possesses consid]able p[]1 & is con/ant 9 its effects = a v long "t1 is greatly sup]ior to all =m] arrangem5ts1 ei!r z an in/rum5t ( rese>*1 or = exhibit+ ! ord9>y ph5om5a ( ,voltaic electricity4 ,a batt]y *>g$ ) wat] alone1 in/ead ( acid1 is con/ant 9 its action1 b ! quantity ( electricity x develops is comp>atively v small4 ,mr4 ,cross1 ( ,broomfield 9 ,som]set%ire1 kept a batt]y ( ?is k9d 9 full =ce dur+ twelve mon?s4 ,m4 ,becqu]el _h inv5t$ an in/rum5t = comp>+ ! int5sities ( ! diff]5t k9ds ( electricity by means ( weights2 b1 z x is impossible to make ! comp>ison ) ,voltaic electricity produc$ by ! ord9>y batt]ies1 on acc\nt ( ! p]petual v>iation to :i* ! int5sity ( ! curr5t is liable1 he has con/ruct$ a batt]y :i* af=ds a cont9u$ /ream ( electricity ( uni=m p[]1 b x is also ( v feeble =ce4 ,! curr5t is produc$ by ! *emical comb9ation ( an acid ) an alkali4 ,metallic contact is n necess>y = ! production ( ,voltaic electricity1 :i* is entirely due to *emical action4 ,! int5sity ( ! ,voltaic electricity is 9 proportion to ! int5sity ( ! aff9ities conc]n$ 9 its production1 & ! quantity produc$ is 9 proportion to ! quantity ( matt] :i* has be5 *emically active dur+ its evolution4 ,dr4 ,f>aday consid]s ?is def9ite production to be "o ( ! /ronge/ pro(s t electricity is ( *emical orig94 ,galvanic or ,voltaic electricity is manife/$ by two cont9u\s =ces or curr5ts pass+ 9 opposite directions ?r\gh ! circuit3 ! z9c is ! positive end or pole ( ! batt]y1 & ! copp] ! negative4 ,voltaic electricity is di/+ui%$ by two m>k$ *>act]s4 ,its int5sity increases ) ! numb] ( plates1 its quantity ) ! ext5t ( _! surfaces4 ,! mo/ int5se conc5tration ( =ce is display$ by a num]\s s]ies ( l>ge plates3 light & heat are copi\sly evolv$1 & *emical decomposition is accompli%$ ) extraord9>y en]gy2 :]eas ! electricity f "o pair ( plates1 :atev] _! size may be1 is s feeble t x gives no sign ei!r ( attraction or repulsion4 ,common or /atic electricity is ( great] int5sity & has a great] p[] ( ov]com+ resi/ance ?an ,voltaic electricity1 b x acts ^u a small] quantity ( matt]4 ,h[ev]1 by dim9i%+ ! size ( ! plates1 & increas+ _! numb]1 ! int5sity ( a batt]y may be increas$ till x becomes equal to t ( ! electrical ma*9e4 ,! action ( ,voltaic electricity diff]s 9 "s respects mat]ially f t ( ! ord9>y k9d4 ,:5 a quantity ( common electricity is accumulat$1 ! re/oration ( equilibrium is att5d$ by an in/antane\s viol5t explosion1 accompani$ by ! developm5t ( light1 heat1 & s\nd4 ,! conc5trat$ p[] ( ! electricity =ces its way ?r\gh e ob/acle1 disrupt+ & de/roy+ ! cohesion ( ! p>ticles ( ! bodies ?r\gh :i* x passes1 & occasionally increas+ its de/ructive effects by ! conv]sion ( fluids into /eam f ! int5sity ( ! mom5t>y heat1 z :5 trees are torn to pieces by a /roke ( lightn+4 ,ev5 ! vivid light :i* m>ks ! pa? ( ! electricity is probably ow+ 9 "p to ! sudd5 compression ( ! air & ! rapidity ( its passage4 ,b ! in/ant equilibrium is re/or$ by ?is en]getic action ! :ole is at an end4 ,on ! contr>y1 :5 an accumulation takes place 9 a ,voltaic batt]y1 equilibrium is re/or$ ! mom5t ! circuit is complet$4 ,b s f> is ! electric /ream f be+ exhau/$1 t x cont9ues to fl[ sil5tly & invisibly 9 an un9t]rupt$ curr5t suppli$ by a p]petual reproduction4 ,&1 al?\gh its action on bodies is nei!r s sudd5 nor s int5se z t ( common electricity1 yet x acquires su* p[] f con/ant accumulation & cont9u$ action1 t x ultimately surpasses ! en]gy ( ! o!r4 ,! two k9ds ( electricity diff] 9 no circum/ance m ?an 9 ! developm5t ( heat4 ,in/ead ( a mom5t>y evolution1 ! circulation ( ! ,voltaic electricity is accompani$ by a cont9u$ developm5t ( heat1 la/+ z long z ! circuit is complete1 )\t produc+ ei!r light or s\nd4 ,its int5sity f a v p[]ful batt]y is great] ?an t ( any heat t c be obta9$ by artificial means1 s t x fuses sub/ances :i* resi/ ! action ( ! mo/ p[]ful furnaces4 ,! temp]ature ( e "p ( a ,voltaic batt]y itself is rais$ dur+ its activity4 ,) ! great] numb] ( metals ,mr4 ,grove f\nd t ! positive t]m9al or pole is hott] ?an ! negative4 ,accord+ to ,mr4 ,j\le1 ! quantity ( heat g5]at$ 9 a unit ( "t is proportional to ! /r5g? ( ! curr5t1 & :5 a galvanic curr5t is employ$ 9 *emical analysis1 ! heat 9 ! entire circuit g5]at$ 9 a unit ( "t is equal to ! "w exp5d$ 9 produc+ x1 m9us t employ$ 9 ! analysis4 ,9 fact1 a curr5t ( electricity _c pass ?r\gh a homog5e\s conductor )\t g5]at+ heat 9 ov]com+ resi/ance1 an effect prov$ by ,mr4 ,j\le to be proportional to ! squ>e ( ! =ce ( ! curr5t1 & ! same 9 :atev] direction ! curr5t may be fl[+4 ,any o!r !rmal action t c take place mu/ dep5d ^u ! het]og5e\sness ( ! circuit1 & mu/ be rev]sible ) ! curr5t4 ,= example1 if a semicircle ( bismu? be jo9$ to a semicircle ( antimony1 an electric curr5t 9 pass+ ?r\gh x produces cold :]e x passes f ! bismu? to ! antimony by absorption1 & heat :]e x passes f ! antimony to ! bismu?4 ,! transit ( ! electricity f pole to pole is accompani$ by light1 & 9 consequ5ce ( ! cont9u\s curr5t sp>ks occur e "t ! contact ( ! wires is ei!r brok5 or r5ew$2 b consid]able int5sity is requisite to enable ! electricity to =ce its way ?r\gh atmosph]ic air or gas4 ,bo? its l5g? & col\r are affect$ by ! d5sity ( ! m$ium ?r\gh :i* x passes4 ,if ! m$ium be gradually r>efi$ ! dis*>ge increases f a sp>k to a lum9\s gl[1 diff]+ 9 col\r 9 diff]5t gases1 b :ite 9 air4 ,:5 v mu* att5uat$ a dis*>ge may be made to pass across #f or #g feet ( space1 :ile 9 air ( ! ord9>y d5sity x w n pass ?r\gh an in*4 ,9 r>efi$ gas x resembles ! ,aurora by its cont9u\s fla%es4 ,:5 ! batt]y is p[]ful ! lum9\s effects are v brilliant4 ,! mo/ spl5did artificial light kn[n is produc$ by fix+ p5cils ( *>coal at ! extremities ( ! wires1 & br++ !m into contact4 ,?is light is ! m rem>kable z x is indep5d5t ( combu/ion1 s9ce ! *>coal suff]s no app>5t *ange1 &1 likewise1 because x is equally vivid 9 su* gases z d n conta9 oxyg54 ,x dep5ds ^u ! molecul> arrangem5t ( ! *>coal2 = ,mr4 ,grove obs]ves t 8c>bon 9 a transp>5t cry/all9e /ate1 z diamond1 is z p]fect a non-conductor z we "k1 :ile 9 an opaque amorph\s /ate1 z graphite or *>coal1 x is "o ( ! be/ conductors3 ?us 9 "o /ate x transmits light & /ops electricity1 9 ! o!r x transmits electricity & /ops light4 ,x is a circum/ance wor?y ( rem>k1 t ! arrangem5t ( molecules :i* r5d]s a solid body capable ( transmitt+ light is mo/ unfav\rable to ! transmission ( electricity1 transp>5t solids be+ v imp]fect conductors ( electricity2 s all gases readily transmit light1 b are among/ ! wor/ conductors ( electricity1 if inde$ !y c be said to conduct x at all4 ,! fact t ! molecul> /ructure or arrangem5t ( a body influ5ces1 inde$ ,i may say det]m9es1 its conduct+ p[]1 is by no means expla9$ by ! !ory ( a fluid2 b if electricity be only a transmission ( =ce or motion1 ! influ5ce ( ! molecul> /ate is j :at w\ld be expect$40 ,pr(essor ,:eat/one1 by fix+ metallic po9ts at ! extremities ( ! wires or poles1 has f\nd t ! appe>ance ( ! spectrum ( ! voltaic arc or vivid flame t is se5 betwe5 ! t]m9als ( a batt]y1 dep5ds1 z 9 /atic electricity1 ^u ! metal f :5ce x is tak54 ,! spectrum ( t f m]cury consi/s ( sev5 def9ite rays1 sep>at$ f ea* o!r by d>k int]vals2 ^! visible rays are two orange l9es close toge!r1 a bright gre5 l9e1 two bluei%-gre5 l9es ne> ea* o!r1 a v bright purple l9e1 &1 la/ly1 a blue l9e4 ,x is ! same :5 x passes ?r\gh c>bonic acid gas1 oxyg5 gas1 air1 or vacuum4 ,! light f z9c1 cadmium1 t91 bismu?1 & lead1 9 a melt$ /ate1 gives simil> results2 b ! numb]1 position1 & col\r ( ! l9es v>y s mu* 9 ea* case1 & ! appe>ances are s diff]5t1 t ! metals may easily be di/+ui%$ f "o ano!r by ?is mode ( inve/igation4 ,! electric sp>k is consid]$ by ,m4 ,ang/rm to be ! ov]lapp+ ( two spectra1 "o ( :i* belongs to ! metal1 & ! o!r to ! gas ?r\gh :i* ! sp>k passes1 & t ! bright l9es v>y ) ! gas z well z ) ! metal4 ,9 an oxyg5 spectrum ! greate/ numb] ( bright l9es occur 9 ! blue & violet1 9 nitrog5 9 ! gre5 & yell[1 & 9 hydrog5 9 ! r$4 ,^! effects mu/ necess>ily be connect$ ) ! *emical & !rmal prop]ties ( ! gases4 ,mr4 ,grove consid]s t ! col\r ( ! voltaic arc1 or flame1 :i* appe>s betwe5 ! poles ( a v p[]ful batt]y1 dep5ds ^u ! sub/ance ( ! metal f :5ce x proce$s & on ! m$ium ?r\gh :i* x passes4 ,! sp>k f z9c is blue1 f silv] x is gre51 f iron x is r$ & sc9tillat+--precisely ! col\rs af=d$ by ^! metals 9 _! ord9>y combu/ion4 ,b ! col\r v>ies also ) ! m$ium ?r\gh :i* ! light passes1 = :5 ! m$ium is *ang$ a *ange takes place 9 ! col\r1 %[+ an affection ( ! int]v5+ matt]4 ,a portion ( ! metal t]m9als or poles is actually transmitt$ ) e electrical or ,voltaic dis*>ge1 :5ce ,mr4 ,grove concludes t ! electrical dis*>ge arises1 at lea/ 9 "p1 f an actual repulsion & sev]ance ( ! electrifi$ matt] itself1 :i* flies (f at ! po9ts ( lea/ resi/ance4 ,he obs]ves t 8! ph5om5a att5d+ ! electric sp>k or ,voltaic arc t5ds to modify consid]ably our previ\s idea ( ! nature ( ! electric =ce z a produc] ( ignition & combu/ion4 ,! ,voltaic arc is p]haps1 /rictly speak+1 nei!r ignition nor combu/ion4 ,x is n simply ignition2 because ! matt] ( ! t]m9als is n m]ely br\ght to a /ate ( inc&esc5ce1 b is physically sep>at$1 & p>tially transf]r$ f "o t]m9al to ano!r1 mu* ( x be+ dissipat$ 9 a vapor\s /ate4 ,x is n combu/ion2 = ! ph5om5a w take place indep5d5tly ( atmosph]ic air1 oxyg5 gas1 or any ( ! bodies usually call$ support]s ( combu/ion2 combu/ion be+ 9 fact *emical union att5d$ ) heat & light4 ,9 ! ,voltaic arc we may h no *emical union1 = if ! exp]im5t be p]=m$ 9 an exhau/$ receiv]1 or 9 nitrog51 ! sub/ance =m+ ! t]m9als is cond5s$ & precipitat$ ^u ! int]ior ( ! vessel1 91 *emically speak+1 an unalt]$ /ate4 ,?us1 to take a v /rik+ example1 if ! ,voltaic dis*>ge be tak5 betwe5 z9c t]m9als 9 an exhau/$ receiv]1 a f9e black p[d] ( z9c is deposit$ on ! sides ( ! receiv]2 ?is c be collect$1 & takes fire readily 9 air by be+ t\*$ ) a mat*1 or ignit$ wire1 in/antly burn+ into :ite oxide ( z9c4 ,to an ord9>y obs]v] ! z9c w\ld appe> to be burn$ twice--fir/ 9 ! receiv]1 :]e ! ph5om5on pres5ts all ! appe>ance ( combu/ion1 &1 secondly1 9 ! real combu/ion 9 air4 ,) iron ! exp]im5t is equally in/ructive4 ,iron is volatiliz$ by ! ,voltaic arc 9 nitrog51 or 9 an exhau/$ receiv]2 & :5 a sc>cely p]ceptible film has l9$ ! receiv]1 if x be wa%$ ) an acid1 x !n gives1 ) f]rocyanide ( potassium1 ! ,prussian-blue precipitate4 ,9 ?is case we readily di/il iron1 a metal by ord9>y means fusible only at a v high temp]ature40 ,ano!r /rong evid5ce t ! ,voltaic dis*>ge consi/s ( ! mat]ial itself ( :i* ! t]m9als are compos$1 is ! peculi> rotation :i* is obs]v$ 9 ! light :5 iron is employ$1 ! magnetic "* ( ?is metal caus+ its p>ticles to rotate by ! influ5ce ( ! ,voltaic curr5t4 ,9 %ort1 ,mr4 ,grove concludes t1 al?\gh x w\ld be ha/y to ass]t t ! electrical disruptive dis*>ge c 9 no case take place )\t ! t]m9als be+ affect$1 yet he _h met ) no in/ance ( su* a result1 provid$ ! dis*>ge _h be5 suffici5tly prolong$1 & ! t]m9als 9 su* a /ate z c\ld be expect$ to r5d] manife/ slight *anges6#ae ,"s ye>s ago ,mr4 ,grove discov]$ t ! electrical dis*>ge possesses c]ta9 phases or fits ( an alt]nate "*1 =m+ r+s ( alt]nate oxidation & deoxidation on metallic surfaces4 ,a highly poli%$ silv] plate 9 an air-pump 0 connect$ ) ! pole ( a p[]ful inductive batt]y1 :ile a f9e metallic wire1 or ev5 a common sew+ ne$le1 0 fix$ at ! o!r pole1 & s arrang$ z to be p]p5dicul> to ! silv] plate1 & v ne>1 b n t\*+ x4 ,by means ( ?is app>atus ! electrical dis*>ge c\ld be s5t ?r\gh any k9d ( r>efi$ m$ia4 ,9 "s ( ! exp]im5ts a s]ies ( conc5tric col\r$ r+s ( oxide alt]nat+ ) r+s ( poli%$ or unoxidat$ silv] 7 =m$ on ! plate "u ! po9t ( ! ne$le or wire4 ,:5 ! plate 0 previ\sly coat$ ) a film ( oxide1 ! oxide 0 remov$ 9 conc5tric spaces by ! dis*>ge1 & increas$ on ! alt]nate ones1 %[+ an alt]nate positive & negative electricity1 or electricity ( an opposite "* 9 ! same dis*>ge4 ,:5 ! silv] plate 0 poli%$ ! c5tre ( ! r+s =m$ on x 0 yell[-gre5 surr\nd$ by blue-gre52 !n a r+ ( poli%$ silv]1 foll[$ by a crimson r+ ) a slight orange t9t on ! inn] side & deep purple on ! out]2 la/ly ! indication ( a poli%$ "o4 ,:5 ! air-pump 0 fill$ ) att5uat$ olefiant gas ! r+s 7 precisely ! same ) ^? se5 9 ?9 plates2 h5ce ! effect is ! same z t produc$ by ! int]f]5ce ( light4 ,9 ^! exp]im5ts ! lum9\s appe>ance ext5d$ f ?ree qu>t]s ( an in* to an in* r\nd ! po9t ( ! ne$le or wire4 ,:5 ! silv] plate 0 connect$ ) ! negative pole ( ! batt]y a poli%$ po9t appe>$ ^u x opposite ! ne$le1 surr\nd$ by a dusky ill-def9$ areola ( a br[n col\r t+$ ) purple :5 view$ 9 "o direction1 & gre5i%-:ite :5 se5 9 ano!r4 ,9 ! pres5t ye> ,mr4 ,gassiot1 ,vice-,presid5t ( ! ,royal ,society1 has %[n t ! /ratifi$ "* ( ! electric dis*>ge is rem>kably develop$ 9 ! ,torricellian vacuum4 ,among ! v>i\s exp]im5ts made by t g5tleman two may be select$ z /rongly illu/rative ( ?is new & s+ul> prop]ty ( electrical light4 ,9 a clos$ glass tube ab\t an in* int]nal diamet] & #ch in*es long1 9 :i* a vacuum _h be5 made1 two plat9um wires 7 h]metically seal$1 #cb in*es ap>t1 & connect$ ) ! poles ( an inductive batt]y4 ,! lum9\s appe>ance at ! two poles 0 v diff]5t :5 electricity pass$ ?r\gh ! wires4 ,a gl[ surr\nd$ ! negative pole1 & 9 close approximation to ! gl[ a well-def9$ d>k space appe>$1 :ile f ! positive pole or wire ! light proce$$ 9 a /ream2 b unless ! *>ge be great or ! tube %ort1 ! /ream w n ext5d to ! black b&1 :i* is totally diff]5t f ! int]v5+ space4 ,:5 dis*>ges ( electricity 7 s5t ?r\gh ?is vacuum tube a s]ies ( b&s or /ratifications 7 =m$ :i* 7 concave t[>ds ! positive pole2 & z 9 ! *anges 9 mak+ & break+ ! circuit ! electricity emanates f ! diff]5t t]m9als or wires1 _! concavities 7 9 opposite directions4 ,:5 in/ead ( plat9um wires n>r[ t9foil coat+s 7 plac$ r\nd ! ext]ior ( ! glass tube & connect$ ) ! wires ( ! batt]y1 brilliant /ratifications fill$ ! int]ior ( ! tube betwe5 ! foil coat+s1 b no d>k b& appe>$4 ,at pres5t ,mr4 ,gassiot is incl9$ to believe t ! d>k b& is due to int]f]5ce2 b t ! /ratifications arise f pulsations or impulses ( a =ce act+ 9 a highly att5uat$ b resi/+ m$ium1 = ev5 ) ! be/ air-pumps x is impossible to make a p]fect void2 he is /ill occupi$ ) exp]im5ts on ?is new subject1 & no d\bt w obta9 v rem>kable results1 ( :i* none c be m extraord9>y ?an 8 discov]y ( ! p[]ful influ5ce ( ! magnet on ?is electric light4 ,! /ratifications are =m$ 9 rapid succession 9 ! tube ) plat9um wires & are turn$ diff]5t ways1 b !y c be sep>at$ at any "p ( ! tube by ! pole ( a magnet r\nd :i* ! :ole /ratifications h a t5d5cy to revolve4 ,9 ! second exp]im5t1 :]e ! t9foil 0 us$1 ! dis*>ge 0 divid$ 9 two by ! pole ( a magnet1 & ! two p>ts _h a t5d5cy to rotate r\nd ! magnet 9 opposite directions4 ,voltaic electricity is a p[]ful ag5t 9 *emical analysis4 ,:5 transmitt$ ?r\gh conduct+ fluids1 x sep>ates !m into _! con/itu5t p>ts1 :i* x conveys 9 an invisible /ate ?r\gh a consid]able space or quantity ( liquid to ! poles1 :]e !y come into evid5ce4 ,num]\s in/ances might be giv51 b ! decomposition ( wat] is p]haps ! mo/ simple & elegant4 ,suppose a glass tube fill$ ) wat]1 & cork$ at bo? ends2 if "o ( ! wires ( an active ,voltaic batt]y be made to pass ?r\gh "o cork1 & ! o!r ?r\gh ! o!r cork1 into ! wat]1 s t ! extremities ( ! two wires %all be opposite & ab\t a qu>t] ( an in* asund]1 *emical action w imm$iately take place1 & gas w cont9ue to rise f ! extremities ( bo? wires till ! wat] has vani%$4 ,if an electric sp>k be !n s5t ?r\gh ! tube1 ! wat] w reappe>4 ,by arrang+ ! exp]im5t s z to h ! gas giv5 out by ea* wire sep>ately1 x is f\nd t wat] consi/s ( two volumes ( hydrog5 & "o ( oxyg54 ,! hydrog5 is giv5 out at ! positive wire ( ! batt]y1 & ! oxyg5 at ! negative4 ,! oxides are also decompos$2 ! oxyg5 appe>s at ! positive pole1 & ! metal at ! negative4 ,! decomposition ( ! alkalies & e>?s by ,sir ,humphry ,davy =m$ a rem>kable era 9 ! hi/ory ( sci5ce4 ,soda1 pota%1 lime1 magnesia1 & o!r sub/ances h]et(ore consid]$ to be simple bodies incapable ( decomposition1 7 resolv$ by electric ag5cy into _! con/itu5t p>ts1 & prov$ to be metallic oxides1 by t illu/ri\s philosoph]4 ,all *emical *anges produc$ by electricity are accompli%$ on ! same pr9ciple2 & x appe>s t1 9 g5]al1 combu/ible sub/ances1 metals1 & alkalies g to ! negative wire1 :ile acids & oxyg5 are evolv$ at ! positive4 ,! transf] ( ^! sub/ances to ! poles is n ! lea/ wond]ful effect ( ! ,voltaic batt]y4 ,?\gh ! poles be at a consid]able di/ance f "o ano!r1 nay1 ev5 9 sep>ate vessels1 if a communication be only e/abli%$ by a quantity ( wet ?read1 z ! decomposition proce$s ! compon5t p>ts pass ?r\gh ! ?read 9 an invisible /ate1 & arrange !mselves at _! respective poles4 ,accord+ to ,dr4 ,f>aday1 electro-*emical decomposition is simply a case ( ! prepond]ance ( "o set ( *emical aff9ities m p[]ful 9 _! nature ov] ano!r set :i* are less p[]ful4 ,& 9 electro-*emical action ( any k9d produc$ by a cont9u\s curr5t1 ! am\nt ( action 9 a giv5 "t is ne>ly1 if n rigor\sly1 proportional to ! /r5g? ( ! curr5t4 ,! great efficacy ( ,voltaic electricity 9 *emical decomposition arises n f its t5sion1 b f ! quantity set 9 motion & ! cont9uance ( its action4 ,its ag5cy appe>s to be mo/ ex]t$ on fluids & sub/ances :i* by convey+ ! electricity p>tially & imp]fectly imp$e its progress4 ,b x is n[ prov$ to be z efficaci\s 9 ! composition z 9 ! decomposition or analysis ( bodies4 ,x _h be5 obs]v$ t1 :5 metallic solutions are subject$ to galvanic action1 a deposition ( metal1 sometimes 9 ! =m ( m9ute cry/als1 takes place on ! negative wire4 ,by ext5d+ ?is pr9ciple1 & employ+ a v feeble ,voltaic action1 ,m4 ,becqu]el has succe$$ 9 =m+ cry/als ( a great proportion ( ! m9]al sub/ances1 precisely simil> to ^? produc$ by nature4 ,! electric /ate ( metallic ve9s makes x possible t _m natural cry/als may h tak5 _! =m f ! action ( electricity br++ _! ultimate p>ticles1 :5 9 solution1 )9 ! n>r[ sph]e ( molecul> attraction4 ,bo? light & motion fav\r cry/allization4 ,cry/als :i* =m 9 diff]5t liquids are g5]ally m abundant on ! side ( ! j> expos$ to ! light2 & x is well kn[n t /ill wat]1 cool$ bel[ #cb1 />ts into cry/als ( ice ! in/ant x is agitat$4 ,a feeble action is alone necess>y1 provid$ x be cont9u$ = a suffici5t "t4 ,cry/als =m$ rapidly are g5]ally imp]fect & s(t1 & ,m4 ,becqu]el f\nd t ev5 ye>s ( con/ant ,voltaic action 7 necess>y = ! cry/allization ( "s ( ! h>d sub/ances4 ,if ?is law be g5]al1 h[ _m ages may be requir$ = ! =mation ( a diamond6 ,! deposition ( metal f a metallic solution by galvanic electricity has be5 mo/ successfully appli$ to ! arts ( plat+ & gild+1 z well z to ! m delicate process ( copy+ m$als & copp] plates4 ,inde$1 n m$als only1 b any object ( art or nature1 may be coat$ ) precipitat$ metal1 provid$ x be fir/ cov]$ ) ! ?9ne/ film ( plumbago1 :i* r5d]s a non-conductor suffici5tly conduct+ to receive ! metal4 ,photo-galvanic engrav+ dep5ds ^u ?is4 ,gelat9e mix$ ) bi*romate ( pota%1 nitrate ( silv]1 & iodide ( potassium1 is spread ov] a plate ( glass1 & :5 dry a positive pr9t is laid ^u x ) its face d[nw>ds1 :i*1 :5 expos$ to ! sun1 leaves its impression4 ,:5 soak$ 9 wat] ! gelat9e swells ar\nd all ^? p>ts :]e ! light _h fall51 ?us =m+ an intaglio1 a ca/ ( :i* is tak5 9 gutta-p]*a1 :i* is !n coat$ ) copp] by ! electro process1 :5ce a copp] plate 9 relief is obta9$4 ,/atic electricity1 on acc\nt ( its high t5sion1 passes ?r\gh wat] & o!r liquids z soon z x is =m$1 :atev] ! l5g? ( its c\rse may be4 ,voltaic electricity1 on ! contr>y1 is weak5$ by ! di/ance x has to trav]se4 ,pure wat] is a v bad conductor2 b ice absolutely /ops a curr5t ( ,voltaic electricity altoge!r1 :atev] be ! p[] ( ! batt]y1 al?\gh /atic or common electricity has suffici5t p[] to ov]come its resi/ance4 ,dr4 ,f>aday has discov]$ t ?is prop]ty is n peculi> to ice2 t1 ) a few exceptions1 bodies :i* d n conduct electricity :5 solid acquire t prop]ty1 & are imm$iately decompos$1 :5 !y become fluid1 &1 9 g5]al1 t decomposition takes place z soon z ! solution acquires ! capacity ( conduction1 :i* has l$ him to suspect t ! p[] ( conduction may be only a consequ5ce ( decomposition4 ,heat increases ! conduct+ p[] ( "s sub/ances = ,voltaic electricity1 & ( ! gases = bo? k9ds4 ,dr4 ,f>aday has giv5 a new pro( ( ! connexion betwe5 heat & electricity1 by %[+ t1 9 g5]al1 :5 a solid1 :i* is n a metal1 becomes fluid1 x almo/ entirely loses its p[] ( conduct+ heat1 :ile x acquires a capacity = conduct+ electricity 9 a high degree4 ,m4 ,becqu]el reg>ds ! production ( heat & t ( electricity to be concomitant2 _! dep5d5ce be+ su*1 t :5 "o is increas$ ! o!r dim9i%es1 & vice v]s1 s t "o may altoge!r disappe> ) ! increase ( ! o!r4 ,= in/ance1 :5 electricity circulates 9 a metallic wire1 ! great] ! heat produc$1 ! less ! quantity ( electricity :i* passes1 & ! contr>y1 s t ! affair proce$s z if electricity 7 conv]t$ into heat1 & heat into electricity4 ,aga91 9 a clos$ galvanic circuit ! sum ( ! heat produc$ 9 ! *emical action ( ! acidulat$ wat] ^u ! z9c & 9 ! conduct+ wire is con/ant1 s t ! quantity ( heat dis5gag$ 9 ! reaction is great] 9 proportion z less electricity passes ?r\gh ! wire4 ,^!1 & o!r circum/ances1 prove su* an intimate connexion betwe5 ! production ( heat & electricity1 t 9 ! *ange ( condition ( sub/ances ! electrical effects might disappe> or be annull$ by ! calorific effects4 ,! galvanic curr5t affects all ! s5ses3 no?+ c be m disagreeable ?an ! %ock1 :i* may ev5 be fatal if ! batt]y be v p[]ful4 ,a bright fla% ( light is p]ceiv$ ) ! eyes %ut1 :5 "o ( ! wires t\*es ! face1 & ! o!r ! h&4 ,by t\*+ ! e> ) "o wire1 & hold+ ! o!r1 /range noises are he>d2 & an acid ta/e is p]ceiv$ :5 ! positive wire is appli$ to ! tip ( ! tongue1 & ! negative wire t\*es "s o!r "p ( x4 ,by rev]s+ ! poles ! ta/e becomes alkal9e4 ,x r5d]s ! pale light ( ! gl[-worm m int5se4 ,dead animals are r\s$ by x1 z if !y />t$ aga9 into life1 & x may ultimately prove to be ! cause ( muscul> action 9 ! liv+4 ,sev]al fi% possess ! faculty ( produc+ electrical effects4 ,! mo/ rem>kable are ! gymnotus electricus1 f\nd 9 ,s\? ,am]ica2 & ! torp$o1 a g5us ( ray1 frequ5t 9 ! ,m$it]ranean4 ,! electrical action ( ! torp$o dep5ds ^u an app>atus app>5tly analog\s to ! ,voltaic pile1 :i* ! animal has ! p[] ( *>g+ at w1 consi/+ ( membran\s columns fill$ ?r\gh\t ) lam91 sep>at$ f "o ano!r by a fluid4 ,! absolute quantity ( electricity br\ght into circulation by ! torp$o is s great1 t x effects ! decomposition ( wat]1 has p[] suffici5t to make magnets1 gives v sev]e %ocks & ! electric sp>k4 ,x is id5tical 9 k9d ) t ( ! galvanic batt]y1 ! electricity ( ! "u surface ( ! fi% be+ ! same ) ! negative pole1 & t 9 ! upp] surface ! same ) ! positive pole4 ,its mann] ( action is1 h[ev]1 some:at diff]5t2 =1 al?\gh ! evolution ( ! electricity is cont9u$ = a s5sible "t1 x is int]rupt$1 be+ communicat$ by a succession ( dis*>ges4 ,,section ,,xxx4 ,discov]y ( ,electro-magnetism--,deflection ( ! ,magnetic ,ne$le by a ,curr5t ( ,electricity--,direction ( ! ,=ce--,rotatory ,motion by ,electricity--,rotation ( a ,wire & a ,magnet--,rotation ( a ,magnet ab\t its ,axis--,( ,m]cury & ,wat]--,electro-,magnetic ,cyl9d] or ,helix--,susp5sion ( a ,ne$le 9 a ,helix--,electro-,magnetic ,induction--,tempor>y ,magnets--,! ,galvanomet]4 ,,! di/urb+ effects ( ! aurora & lightn+ on ! m>9]'s compass _h be5 long kn[n4 ,9 ! ye> #ahai ,m4 ,o]/$1 ,pr(essor ( ,natural ,philosophy at ,cop5hag51 discov]$ t a curr5t ( ,voltaic electricity ex]ts a p[]ful influ5ce on a magnetiz$ ne$le4 ,?is obs]vation has giv5 rise to ! !ory ( electro-magnetism--"o ( ! mo/ int]e/+ sci5ces ( mod]n times1 :e!r x be consid]$ z lead+ u a /ep f>!r 9 g5]alization1 by id5tify+ two ag5cies hi!rto ref]r$ to diff]5t causes1 or z develop+ a new =ce1 unp>allel$ 9 ! sy/em ( ! _w1 :i*1 ov]com+ ! ret>dation f friction1 & ! ob/acle ( a resi/+ m$ium1 ma9ta9s a p]petual motion z long z ! action ( a ,voltaic batt]y is cont9u$4 ,:5 ! two poles ( a ,voltaic batt]y are connect$ by a metallic wire1 s z to complete a circuit1 ! electricity fl[s )\t ceas+4 ,if a /raight portion ( t wire be plac$ p>allel to1 & horizontally above1 a magnetiz$ ne$le at re/ 9 ! magnetic m]idian1 b freely pois$ l ! m>9]'s compass1 ! action ( ! electric curr5t fl[+ ?r\gh ! wire w in/antly cause ! ne$le to *ange its position4 ,its extremity w deviate f ! nor? t[>ds ! ea/ or we/1 accord+ to ! direction 9 :i* ! curr5t is fl[+2 &1 on rev]s+ ! direction ( ! curr5t1 ! motion ( ! ne$le w be rev]s$ also4 ,! num]\s exp]im5ts t h be5 made on magnetism & electricity1 z well z ^? on ! v>i\s relative motions ( a magnetic ne$le "u ! influ5ce ( galvanic electricity1 aris+ f all possible positions ( ! conduct+ wire1 & e direction ( ! ,voltaic curr5t1 toge!r ) all ! o!r ph5om5a ( electro-magnetism1 are expla9$ by ,dr4 ,roget 9 "s excell5t articles on ^! subjects 9 ! ,libr>y ( ,useful ,k4 ,all exp]im5ts t5d to prove t ! =ce emanat+ f ! electric curr5t1 :i* produces su* effects on ! magnetic ne$le1 acts at "r angles to ! curr5t4 ,! action ( an electrical curr5t ^u ei!r pole ( a magnet has no t5d5cy to cause ! pole to approa* or rec$e1 b to rotate ab\t x4 ,if ! /ream ( electricity be suppos$ to pass ?r\gh ! c5tre ( a circle ^: plane is p]p5dicul> to ! curr5t1 ! direction ( ! =ce ex]t$ by ! electricity w always be 9 ! tang5t to ! circle1 or at "r angles to its radius 7,n4 #bbc74 ,consequ5tly1 ! tang5tial =ce ( ! electricity has a t5d5cy to make ! pole ( a magnet move 9 a circle r\nd ! wire ( ! batt]y4 ,rotatory motion 0 sugge/$ by ,dr4 ,wolla/on4 ,dr4 ,f>aday 0 ! fir/ :o actually succe$$ 9 mak+ ! pole ( a magnet rotate ab\t a v]tical conduct+ wire4 ,9 ord] to limit ! action ( ! electricity to "o pole1 ab\t two-?irds ( a small magnet 7 imm]s$ 9 m]cury1 ! l[] end be+ fa/5$ by a ?read to ! bottom ( ! vessel conta9+ ! m]cury4 ,:5 ! magnet 0 ?us float+ almo/ v]tically ) its nor? pole above ! surface1 a curr5t ( positive electricity 0 made to desc5d p]p5dicul>ly ?r\gh a wire t\*+ ! m]cury1 & imm$iately ! magnet began to rotate f left to "r ab\t ! wire4 ,! =ce be+ uni=m1 ! rotation 0 accel]at$ till ! tang5tial =ce 0 balanc$ by ! resi/ance ( ! m]cury1 :5 x became con/ant4 ,"u ! same circum/ances ! s\? pole ( ! magnet rotates f "r to left4 ,x is evid5t1 f ?is exp]im5t1 t ! wire may also be made to p]=m a rotation r\nd ! magnet1 s9ce ! action ( ! curr5t ( electricity on ! pole ( ! magnet mu/ necess>ily be accompani$ by a correspond+ reaction ( ! pole ( ! magnet on ! electricity 9 ! wire4 ,?is exp]im5t has be5 accompli%$ by a va/ numb] ( contrivances1 & ev5 a small batt]y1 consi/+ ( two plates1 has p]=m$ ! rotation4 ,dr4 ,f>aday produc$ bo? motions at ! same "t 9 a vessel conta9+ m]cury2 ! wire & ! magnet revolv$ 9 "o direction ab\t a common c5tre ( motion1 ea* foll[+ ! o!r4 ,! next /ep 0 to make a magnet1 & also a cyl9d]1 revolve ab\t _! own axes1 :i* !y d ) great rapidity4 ,m]cury has be5 made to rotate by means ( ,voltaic electricity1 & ,pr(essor ,rit*ie exhibit$ 9 ! ,royal ,in/itution ! s+ul> spectacle ( ! rotation ( wat] by ! same means1 :ile ! vessel conta9+ x rema9$ /ation>y4 ,! wat] 0 9 a holl[ d\ble cyl9d] ( glass1 &1 on be+ made ! conductor ( electricity1 0 obs]v$ to revolve 9 a regul> vortex1 *ang+ its direction z ! poles ( ! batt]y 7 alt]nately rev]s$4 ,pr(essor ,rit*ie f\nd t all ! diff]5t conductors hi!rto tri$ by him1 su* z wat]1 *>coal1 c41 give ! same electro-magnetic results :5 transmitt+ ! same quantity ( electricity1 & t !y deflect ! magnetic ne$le 9 an equal degree :5 _! respective axes ( conduction are at ! same di/ance f x4 ,b "o ( ! mo/ extraord9>y effects ( ?is =ce is exhibit$ by coil+ a copp] wire1 s z to =m a helix or corkscrew1 & connect+ ! extremities ( ! wire ) ! poles ( a galvanic batt]y4 ,if a magnetiz$ /eel b> or ne$le be plac$ )9 ! screw1 s z to re/ ^u ! l[] "p1 ! in/ant a curr5t ( electricity is s5t ?r\gh ! wire ( ! helix1 ! /eel b> />ts up by ! influ5ce ( ?is invisible p[]1 & rema9s susp5d$ 9 ! air 9 opposition to ! =ce ( gravitation 7,n4 #bbd74 ,! effect ( ! electro-magnetic p[] ex]t$ by ea* turn ( ! wire is to urge ! nor? pole ( ! magnet 9 "o direction1 & ! s\? pole 9 ! o!r4 ,! =ce ?us ex]t$ is multipli$ 9 degree & increas$ 9 ext5t by ea* repetition ( ! turns ( ! wire1 & 9 consequ5ce ( ^! oppos+ =ces ! b> rema9s susp5d$4 ,?is helix has all ! prop]ties ( a magnet :ile ! electrical curr5t is fl[+ ?r\gh x1 & may be sub/itut$ = "o 9 almo/ e exp]im5t4 ,x acts z if x _h a nor? pole at "o extremity & a s\? pole at ! o!r1 & is attract$ & repell$ by ! poles ( a magnet exactly z if x 7 "o itself4 ,all ^! results dep5d ^u ! c\rse ( ! electricity2 t is1 on ! direction ( ! turns ( ! screw1 accord+ z x is f "r to left1 or f left to "r1 be+ contr>y 9 ! two cases4 ,! action ( ,voltaic electricity on a magnet is n only precisely ! same ) ! action ( two magnets on "o ano!r1 b its influ5ce 9 produc+ tempor>y magnetism 9 iron & /eel is also ! same ) magnetic induction4 ,! t]m induction1 :5 appli$ to electric curr5ts1 expresses ! p[] :i* ^! curr5ts possess ( induc+ a p>ticul> /ate ^u matt] 9 _! imm$iate neighb\rhood1 o!rwise neutral or indiff]5t4 ,= example1 ! connect+ wire ( a galvanic batt]y holds iron fil+s susp5d$ l a magnet z long z ! curr5t cont9ues to fl[ ?r\gh x3 ! iron becomes magnetic by ! induction ( ! curr5t4 ,! mo/ p[]ful tempor>y magnets are obta9$ by b5d+ a ?ick cyl9d] ( s(t iron into ! =m ( a horse%oe1 & surr\nd+ x ) a coil ( ?ick copp] wire cov]$ ) silk to prev5t communication betwe5 its coils4 ,:5 ?is wire =ms "p ( a galvanic circuit ! iron becomes s highly magnetic by ! induction ( ! curr5t fl[+ ?r\gh ! wire t a tempor>y magnet ( ?is k9d made by ,pr(essor ,h5ry ( ! ,albany ,academy 9 ! ,unit$ ,/ates su/a9$ a weight ( ne>ly a ton4 ,ano!r by ,mr4 ,gage has be5 appli$ ) consid]able success z a mov+ p[]3 its sp>k is a bright fla%1 & ! snap z l\d z a pi/ol4 ,b ! mo/ p[]ful kn[n is t employ$ by ,mr4 ,j\le 9 8 exp]im5ts1 :i* su/a9s a weight ( #bjhj lbs4 ,! iron loses its magnetism ! in/ant ! electricity ceases to fl[1 & acquires x aga9 z in/antane\sly :5 ! circuit is r5ew$4 ,! action ( an electric curr5t causes a deviation ( ! compass f ! plane ( ! magnetic m]idian4 ,9 proportion z ! ne$le rec$es f ! m]idian1 ! int5sity ( ! =ce ( t]re/rial magnetism increases1 :ile at ! same "t ! electro-magnetic =ce dim9i%es2 ! numb] ( degrees at :i* ! ne$le /ops1 %[+ :]e ! equilibrium betwe5 ^! two =ces takes place1 w indicate ! int5sity ( ! galvanic curr5t4 ,! galvanomet]1 con/ruct$ ^u ?is pr9ciple1 is employ$ to measure ! int5sity ( galvanic curr5ts collect$ & convey$ to x by wires4 ,?is in/rum5t is r5d]$ mu* m s5sible by neutraliz+ ! effects ( ! e>?'s magnetism on ! ne$le1 :i* is accompli%$ by plac+ a second magnetis$ ne$le s z to c\nt]act ! action ( ! e>? on ! fir/--a precaution requisite 9 all delicate magnetical exp]im5ts4 ,x has be5 asc]ta9$ by means ( ?is in/rum5t t ! action ( an electrical curr5t ^u a magnet is inv]sely z ! squ>e ( ! di/ance1 & ! en]gy ) :i* an electro magnet acts is directly z ! p[] ( ! galvanic batt]y & ! numb] ( coils r\nd ! core1 & inv]sely z ! resi/ance ( ! wire4 ,,section ,,xxxi4 ,electro-,dynamics--,reciprocal ,action ( ,electric ,curr5ts--,id5tity ( ,electro-,dynamic ,cyl9d]s & ,magnets--,diff]5ces betwe5 ! ,action ( ,voltaic ,electricity & ,electricity ( ,t5sion--,effects ( a ,voltaic ,curr5t--,ampre's ,!ory--,dr4 ,f>aday's ,exp]im5t ( ,electrify+ & ,magnetis+ a ,ray ( ,light4 ,,! sci5ce ( electro-magnetism1 :i* mu/ r5d] ! "n ( ,m4 ,o]/$ ev] memorable1 relates to ! reciprocal action ( electrical & magnetic curr5ts3 ,m4 ,ampre1 by discov]+ ! mutual action ( electrical curr5ts on "o ano!r1 has add$ a new bran* to ! subject1 to :i* he has giv5 ! "n ( electro-dynamics4 ,:5 electric curr5ts are pass+ ?r\gh two conduct+ wires1 s susp5d$ or support$ z to be capable ( mov+ bo? t[>ds & f "o ano!r1 !y %[ mutual attraction or repulsion1 accord+ z ! curr5ts are fl[+ 9 ! same or 9 contr>y directions2 ! ph5om5a v>y+ ) ! relative incl9ations & positions ( ! /reams ( electricity4 ,! mutual action ( su* curr5ts1 :e!r !y fl[ 9 ! same or 9 contr>y directions1 :e!r !y be p>allel1 p]p5dicul>1 div]g+1 conv]g+1 circul>1 or heliacal1 all produce diff]5t k9ds ( motion 9 a conduct+ wire1 bo? rectil9eal & circul>1 & also ! rotation ( a wire helix1 su* z t describ$1 n[ call$ an electro-dynamic cyl9d] on acc\nt ( "s improvem5ts 9 its con/ruction 7,n4 #bbe74 ,&1 z ! hypo!sis ( a =ce v>y+ inv]sely z ! squ>e ( ! di/ance accords p]fectly ) all ! obs]v$ ph5om5a1 ^! motions come "u ! same laws ( dynamics & analysis z any o!r bran* ( physics4 ,electro-dynamic cyl9d]s act on ea* o!r precisely z if !y 7 magnets dur+ ! "t ! electricity is fl[+ ?r\gh !m4 ,all ! exp]im5ts t c be p]=m$ ) ! cyl9d] might be accompli%$ ) a magnet4 ,t end ( ! cyl9d] 9 :i* ! curr5t ( positive electricity is mov+ 9 a direction simil> to ! motion ( ! h&s ( a wat*1 acts z ! s\? pole ( a magnet1 & ! o!r end1 9 :i* ! curr5t is fl[+ 9 a contr>y direction1 exhibits nor!rn pol>ity4 ,! ph5om5a m>k a v decid$ diff]5ce betwe5 ! action ( electricity 9 motion or at re/1 t is1 betwe5 ,voltaic & /atic electricity2 ! laws !y foll[ are 9 _m respects ( an entirely diff]5t nature1 ?\gh ! electricities !mselves are id5tical4 ,s9ce ,voltaic electricity fl[s p]petually1 x _c be accumulat$1 & consequ5tly has no t5sion1 or t5d5cy to escape f ! wires :i* conduct x4 ,nor d ^! wires ei!r attract or repel light bodies 9 _! vic9ity1 :]eas /atic or ord9>y electricity c be accumulat$ 9 insulat$ bodies to a great degree1 & 9 t /ate ( re/ ! t5d5cy to escape is proportional to ! quantity accumulat$ & ! resi/ance x meets )4 ,9 ord9>y electricity1 ! law ( action is1 t dissimil> electricities attract & simil> electricities repel "o ano!r4 ,9 ,voltaic electricity1 on ! contr>y1 simil> curr5ts1 or su* z are mov+ 9 ! same direction1 attract "o ano!r1 :ile a mutual repulsion is ex]t$ betwe5 dissimil> curr5ts1 or su* z fl[ 9 opposite directions4 ,common electricity escapes :5 ! pressure ( ! atmosph]e is remov$1 b ! electro-dynamical effects are ! same :e!r ! conductors be 9 air or 9 vacuo4 ,! effects produc$ by a curr5t ( electricity dep5d ^u ! cel]ity ( its motion ?r\gh a conduct+ wire4 ,yet we are ignorant :e!r ! motion be uni=m or v>i$1 b ! me?od ( transmission has a m>k$ influ5ce on ! results2 =1 :5 x fl[s )\t int]mission1 x occasions a deviation 9 ! magnetic ne$le1 b x has no effect :atev] :5 its motion is discont9u\s or int]rupt$1 l ! curr5t produc$ by ! common electrical ma*9e :5 a communication is made betwe5 ! positive & negative conductors4 ,m4 ,ampre has e/abli%$ a !ory ( electro-magnetism sugge/$ by ! analogy betwe5 electro-dynamic cyl9d]s & magnets1 f\nd$ ^u ! reciprocal attraction ( electro-curr5ts1 to :i* he r$uces all ! ph5om5a ( magnetism & electro-magnetism1 by assum+ t ! magnetic prop]ties :i* bodies possess d]ive ^! prop]ties f curr5ts ( electricity1 circulat+ ab\t e "p 9 "o uni=m direction4 ,al?\gh e p>ticle ( a magnet possesses l prop]ties ) ! :ole1 yet ! g5]al effect is ! same z if ! magnetic prop]ties 7 conf9$ to ! surface4 ,consequ5tly1 ,ampre concludes t ! int]nal electro-curr5ts mu/ comp5sate "o ano!r1 & t ! magnetism ( a body mu/ !re=e arise f a sup]ficial curr5t ( electricity con/antly circulat+ 9 a direction p]p5dicul> to ! axis ( ! magnet2 s t ! reciprocal action ( magnets & all ! ph5om5a ( electro-magnetism are r$uc$ to ! action & reaction ( sup]ficial curr5ts ( electricity1 act+ at "r angles to _! direction4 ,not)/&+ ! exp]im5ts made by ,ampre to elucidate ! subject1 !re is /ill an unc]ta9ty 9 ! !ory ( ! induction ( magnetism by an electric curr5t 9 a body ne> x4 ,x does n appe> :e!r electric curr5ts :i* did n previ\sly exi/ are actually produc$ by induction1 or if its effect be only to give "o uni=m direction to ! inf9ite numb] ( electric curr5ts previ\sly exi/+ 9 ! p>ticles ( ! body1 & ?us r5d]+ !m capable ( exhibit+ magnetic ph5om5a1 9 ! same mann] z pol>ization r$uces ! undulations ( light to "o plane1 :i* _h previ\sly be5 p]=m$ 9 e plane4 ,possibly bo? may be comb9$ 9 produc+ ! effect2 = ! action ( ! electric curr5t may n only give a common direction to ^? already exi/+1 b may also increase _! int5sity4 ,h[ev] t may be1 by assum+ t ! attractions & repulsions ( ! elem5t>y portions ( electric curr5ts v>y inv]sely z ! squ>e ( ! di/ance1 ! actions be+ at "r angles to ! direction ( ! curr5t1 x is f\nd t ! attraction & repulsion ( a curr5t ( indef9ite l5g? on ! elem5t>y portion ( a p>allel curr5t at any di/ance f x are 9 ! simple ratio ( ! %orte/ di/ance betwe5 !m3 consequ5tly1 ! reciprocal action ( electric curr5ts is r$uc$ to ! composition & resolution ( =ces1 s t ! ph5om5a ( electro-magnetism are br\ght "u ! laws ( me*anics by ! !ory ( ,ampre4 ,x appe>s t ,dr4 ,f>aday's v rem>kable exp]im5t ( electrify+ & magnetis+ a ray ( pol>iz$ light may possibly af=d a demon/ration ( ! reality ( ,ampre's explanation ( ! ultimate nature ( magnetism4 ,9 ?is exp]im5t a copp] wire #eja feet long 0 arrang$ 9 f\r conc5tric spirals1 ! extremities ( :i* 7 connect$ ) ! poles ( a p[]ful galvanic batt]y1 & a poli%$ prism ( heavy glass1 or silicat$ borate ( lead1 0 plac$ 9 ! axis ( ! spiral z a core1 ?r\gh ! l5g? or axis ( :i* a ray ( pol>iz$ light 0 s5t4 ,?is ray1 view$ ?r\gh a piece ( t\rmal9e or a ,ni*ol's eye-piece1 vani%$ & reappe>$ z usual at ea* qu>t] revolution ( ! eye-piece2 b :5 a curr5t ( electricity 0 s5t ?r\gh ! spiral at ! "t ! ray _h vani%$1 x in/antly reappe>$1 & rema9$ z long z ! electric curr5t cont9u$ to fl[2 b ! in/ant ! electricity ceas$ ! light vani%$1 & z (t5 z ! electric curr5t fl[$ ?r\gh ! spiral1 or 0 int]rupt$1 s (t5 did ! pol>iz$ ray appe> & vani%4 ,! "* ( ! =ce ?us impress$ on ! heavy glass is t ( rotation1 = ! /opp+ & r5ew+ ( ! electric curr5t _h ! same effect z ! revolv+ motion ( ! eye-piece 9 mak+ ! light alt]nately appe> & vani%4 ,accord+ly1 ,dr4 ,f>aday f\nd t1 :5 ! electricity fl[$ ?r\gh ! spiral 9 "o direction1 ! rotation ( ! plane ( pol>ization 0 "r-h&$2 & :5 x fl[$ 9 ! o!r direction1 ! rotation ( ! plane ( pol>ization 0 left-h&$1 ! rotation increas+ ) ! l5g? ( ! prism & ! int5sity ( ! electricity4 ,! same ph5om5a 7 produc$ by a v p[]ful magnet :5 a ray ( pol>iz$ light 0 s5t ?r\gh ! heavy glass p>allel to ! l9e ( magnetic =ce4 ,heavy glass or silico-borate ( lead has ! prop]ty m ?an any o!r sub/ance ( mak+ light rotate "u electric & magnetic influ5ce2 b _m sub/ances h ! prop]ty m or less1 z fl9t & cr[n glass1 rock salt1 all ! fix$ & ess5tial oils1 wat]1 & _m o!r liquids1 b none ( ! gases possess x4 ,9 ^? sub/ances t h ! p[] ( circul> pol>ization naturally1 ! magnetic & electric influ5ces increase or dim9i% ! rotation accord+ to its direction4 ,pol>iz$ heat is made to revolve 9 ! same mann]1 :5 ! m$ium ?r\gh :i* x passes is subject to magnetic influ5ce4 ,mr4 ,grove obs]ves t if light & heat be m]ely modes ( =ce1 :i* !re is e reason to believe t !y are1 x may be fairly /at$ t 9 ^! exp]im5ts magnetism affects ^! =ces directly2 = light & heat be+1 9 t view1 motions ( ord9>y matt]1 magnetism 9 affect+ ^! movem5ts affects ! =ces :i* occasion !m4 ,if1 h[ev]1 ?is effect ( magnetism be a molecul> *ange ( ! matt] transmitt+ ! light & heat1 !n x foll[s t ! light & heat are indirectly affect$ by ! electricity or magnetism4 ,dr4 ,f>aday says t ! magnetic =ces d n act on ! ray ( light directly1 )\t ! int]v5tion ( matt]1 b ?r\gh ! m$iation ( ! sub/ance 9 :i* !y & ! ray h a simultane\s exi/5ce2 ! sub/ances & ! =ces giv+ to & receiv+ f ea* o!r ! p[] ( act+ on ! light4 ,dr4 ,?omson has %[n1 by a ma!matical inve/igation ( ! subject1 t ,dr4 ,f>aday's discov]y seems to prove ! tru? ( ,ampre's explanation ( ! ultimate nature ( magnetism4 ,h[ev]1 9 ,ampre's !ory1 ! curr5t ( electricity fl[+ r\nd ! iron makes x a p]man5t magnet1 b x does n make ! heavy glass or ! o!r bodies1 :i* h ! same prop]ty1 ei!r tempor>y magnets :5 ! light is rotat+ )9 !m1 or p]man5t magnets :5 ! inductive action ( ! curr5t ( electricity ceases4 ,h5ce ! molecul> condition ( ! sub/ances1 :5 ! light is rotat+ 9 !m1 mu/ be specifically di/9ct f t ( magnetis$ iron3 x mu/ !re=e be a new magnetic condition1 & ! =ce :i* ! matt] 9 ?is /ate possesses mu/ be a new magnetic =ce4 ,aft] describ+ 8 admirable exp]im5t1 ,dr4 ,f>aday obs]ves t 8x has e/abli%$ = ! fir/ "t a true1 direct relation & dep5d5ce betwe5 light & ! magnetic & electric =ces2 & ?us a great addition is made to ! facts & consid]ations :i* t5d to prove t all natural =ces are ti$ toge!r1 & h "o common orig94 ,x is no d\bt difficult1 9 ! pres5t /ate ( our k1 to express our expectations 9 exact t]ms2 & ?\gh ,i h said t ano!r ( ! p[]s ( nature is 9 ^! exp]im5ts directly relat$ to ! re/1 ,i ought p]haps r to say t ano!r =m ( ! great p[] is di/9ctly & directly relat$ to ! o!r =ms2 or t ! great p[] manife/$ by p>ticul> ph5om5a 9 p>ticul> =ms is "h fur!r id5tifi$ & recognis$ by ! direct relation ( its =m ( light to its =ms ( electricity & magnetism4 ,! relation exi/+ betwe5 pol>iz$ light & magnetism & electricity is ev5 m int]e/+ ?an if x _h be5 %[n to exi/ ) common light only4 ,x _c b ext5d to common light2 &1 z x belongs to light made 9 a c]ta9 respect m precise 9 its "* & prop]ties by pol>ization1 x collates & connects x ) ^! p[]s 9 t duality ( "* :i* !y possess1 & yields an op5+1 :i* be=e 0 want+ to u1 = ! appliances ( ^! to ! inve/igation ( ! nature ( ?is & o!r radiant ag5cies40 ,?us ,dr4 ,f>aday's exp]im5t n only %[s ! increas+ connexion betwe5 ! sci5ces1 b ! t5d5cy ( all ! =ces ( nature to m]ge 9 "o great & univ]sal p[]4 ,9 ! action ( a magnet ^u ! /ratifications ( an electrical dis*>ge ,mr4 ,gassiot has discov]$ a new in/ance ( ! connexion betwe5 magnetism & light4 ,,section ,,xxxii4 ,magneto-,electricity--,volta-,electric ,induction--,magneto-,electric ,induction--,id5tity 9 ! ,action ( ,electricity & ,magnetism--,description ( a ,magneto-,electric ,app>atus & its ,effects--,id5tity ( ,magnetism & ,electricity--,! ,subm>9e ,telegraph4 ,,f ! law ( action & reaction be+ equal & contr>y1 x might be expect$ t1 z electricity p[]fully affects magnets1 s1 conv]sely1 magnetism ought to produce electrical ph5om5a4 ,by prov+ ?is v important fact f ! foll[+ s]ies ( int]e/+ & +5i\s exp]im5ts1 ,dr4 ,f>aday has add$ ano!r bran* to ! sci5ce :i* he has nam$ magneto-electricity4 ,a great quantity ( copp] wire 0 coil$ 9 ! =m ( a helix r\nd "o half ( a r+ ( s(t iron1 & connect$ ) a galvanic batt]y2 :ile a simil> helix connect$ ) a galvanomet] 0 w\nd r\nd ! o!r half ( ! r+1 b n t\*+ ! fir/ helix4 ,z soon z contact 0 made ) ! batt]y1 ! ne$le ( ! galvanomet] 0 deflect$4 ,b ! action 0 transitory2 =1 :5 ! contact 0 cont9u$1 ! ne$le return$ to its usual position1 & 0 n affect$ by ! cont9ual fl[ ( ! electricity ?r\gh ! wire connect$ ) ! batt]y4 ,z soon1 h[ev]1 z ! contact 0 brok51 ! ne$le ( ! galvanomet] 0 aga9 deflect$1 b 9 ! contr>y direction4 ,simil> effects 7 produc$ by an app>atus consi/+ ( two helices ( copp] wire coil$ r\nd a block ( wood1 in/ead ( iron1 f :i* ,dr4 ,f>aday inf]s t ! electric curr5t pass+ f ! batt]y ?r\gh "o wire induces a simil> curr5t ?r\gh ! o!r wire1 b only at ! in/ant ( contact1 & t a mom5t>y curr5t is induc$ 9 a contr>y direction :5 ! passage ( ! electricity is sudd5ly int]rupt$4 ,^! brief curr5ts or waves ( electricity 7 f\nd to be capable ( magnetiz+ ne$les1 ( pass+ ?r\gh a small ext5t ( fluid1 &1 :5 *>coal po9ts 7 int]pos$ 9 ! curr5t ( ! induc$ helix1 a m9ute sp>k 0 p]ceiv$ z (t5 z ! contacts 7 made or brok51 b nei!r *emical action nor any o!r electric effects 7 obta9$4 ,a deviation ( ! ne$le ( ! galvanomet] took place :5 common magnets 7 employ$ in/ead ( ! ,voltaic curr5t2 s t ! magnetic & electric =ces are id5tical 9 _! effects 9 ?is exp]im5t4 ,aga91 :5 a helix =m$ ( #bbj feet ( copp] wire1 into :i* a cyl9d] ( s(t iron 0 introduc$1 0 plac$ betwe5 ! nor? & s\? poles ( two b> magnets1 & connect$ ) ! galvanomet] by means ( wires f ea* extremity1 z (t5 z ! magnets 7 br\ght into contact ) ! iron cyl9d] x became magnetic by induction1 & produc$ a deflection 9 ! ne$le ( ! galvanomet]4 ,on cont9u+ ! contact ! ne$le resum$ its natural position1 &1 :5 ! contact 0 brok51 deflection took place 9 ! opposite direction2 :5 ! magnetic contacts 7 rev]s$1 ! deflection 0 rev]s$ also4 ,) /rong magnets1 s p[]ful 0 ! action1 t ! ne$le ( ! galvanomet] :irl$ r\nd sev]al times successively2 & simil> effects 7 produc$ by ! m]e approximation or removal ( ! helix to ! poles ( ! magnets4 ,?us x 0 prov$ t magnets produce ! v same effects on ! galvanomet] t electricity does4 ,?\gh at t "t no *emical decomposition 0 effect$ by ^! mom5t>y curr5ts :i* emanate f ! magnets1 !y agitat$ ! limbs ( a frog2 & ,dr4 ,f>aday ju/ly obs]ves1 t 8an ag5t :i* is conduct$ along metallic wires 9 ! mann] describ$1 :i*1 :il/ s pass+1 possesses ! peculi> magnetic actions & =ce ( a curr5t ( electricity1 :i* c agitate & convulse ! limbs ( a frog1 & :i* f9ally c produce a sp>k by its dis*>ge ?r\gh *>coal1 c only be electricity40 ,soon aft] he completely e/abli%$ ! id5tity ( ! two p[]s by produc+ ! sp>k1 heat+ metallic wires1 & accompli%+ *emical decomposition4 ,h5ce x appe>s t electrical curr5ts are evolv$ by magnets1 :i* produce ! same ph5om5a ) ! electrical curr5ts f ! ,voltaic batt]y3 !y1 h[ev]1 diff] mat]ially 9 ?is respect--t "t is requir$ = ! ex]cise ( ! magnetico-electric induction1 :]eas ,volta-electric induction is in/antane\s4 ,?us ! effect ( induction or ! influ5ce ( ! spiral wire 9 increas+ ! electric & magnetic p[] is v great inde$1 & to t we are indebt$ = ! electric telegraph1 = ,voltaic electricity alone is too feeble to ov]come ! resi/ance ( a long wire4 ,electric curr5ts1 :atev] _! t5sion may be1 produce ! ph5om5a ( induction2 ^! aga9 induce o!r curr5ts 9 bodies capable ( induction1 & s on indef9itely2 ! fir/ & second fl[ 9 ! same direction1 ! o!rs alt]nately opposite & direct4 ,!y all give ! %ock & c decompose wat]1 b ) ,volta-electric curr5ts ! elevation ( temp]ature z well z _! physiological & magnetic effects are produc$ by in/antane\s actions1 :i* only dep5d ^u ! quantity & t5sion ( ! curr5t1 & by no means on its duration1 = induc$ curr5ts only exi/ = a mom5t :5 ! circuit ( ! batt]y is brok54 ,! mo/ en]getic physiological effects are produc$ by a small quantity ( electricity mov+ ) great velocity4 ,! app>atus fir/ employ$ by ,dr4 ,f>aday is 9 effect a batt]y1 :]e ! ag5t is ! magnetic in/ead ( ! ,voltaic =ce1 or1 9 o!r words1 electricity1 & is ?us con/ruct$3-- ,a v p[]ful horse%oe magnet1 =m$ ( twelve /eel plates 9 close approximation1 is plac$ 9 a horizontal position4 ,an armature1 consi/+ ( a b> ( ! pure/ s(t iron1 has ea* ( its ends b5t at "r angles1 s t ! faces ( ^? ends may be br\ght directly opposite & close to ! poles ( ! magnet :5 requir$4 ,t5 copp] wires--cov]$ ) silk1 9 ord] to insulate !m--are w\nd r\nd "o half ( ! b> ( s(t iron1 z a comp\nd helix3 t5 o!r wires1 also insulat$1 are w\nd r\nd ! o!r half ( ! b>4 ,! extremities ( ! fir/ set ( wires are 9 metallic connexion ) a circul> disc1 :i* dips into a cup ( m]cury1 :ile ! ends ( ! o!r t5 wires 9 ! opposite direction are sold]$ to a project+ screw-piece1 :i* c>ries a slip ( copp] ) two opposite po9ts4 ,! /eel magnet is /ation>y2 b :5 ! armature1 toge!r ) its app5dages1 is made to rotate v]tically1 ! edge ( ! disc always rema9s imm]s$ 9 ! m]cury1 :ile ! po9ts ( ! copp] slip alt]nately dip 9 x & rise above x4 ,by ! ord9>y laws ( induction1 ! armature becomes a tempor>y magnet :ile its b5t ends are opposite ! poles ( ! /eel magnet1 & ceases to be magnetic :5 !y are at "r angles to !m4 ,x imp>ts its tempor>y magnetism to ! helices :i* conc5trate x2 &1 :ile "o set conveys a curr5t to ! disc1 ! o!r set conducts ! opposite curr5t to ! copp] slip4 ,z ! edge ( ! revolv+ disc is always imm]s$ 9 ! m]cury1 "o set ( wires is con/antly ma9ta9$ 9 contact ) x1 & ! circuit is only complet$ :5 a po9t ( ! copp] slip dips 9 ! m]cury also2 b ! circuit is brok5 ! mom5t t po9t rises above x4 ,?us1 by ! rotation ( ! armature1 ! circuit is alt]nately brok5 & r5ew$2 & z x is only at ^! mom5ts t electric action is manife/$1 a brilliant sp>k takes place e "t ! copp] po9t leaves ! surface ( ! m]cury4 ,plat9um wire is ignit$1 %ocks sm>t en\gh to be disagreeable are giv51 & wat] is decompos$ ) a/oni%+ rapidity1 by ! same means2 :i* proves1 beyond a d\bt1 ! id5tity ( ! magnetic & electric ag5cies1 & places ,dr4 ,f>aday1 ^: exp]im5ts e/abli%$ ! pr9ciple1 9 ! fir/ rank ( exp]im5tal philosoph]s4 ,a magneto-electric ma*9e has be5 rec5tly con/ruct$ by ,mr4 ,h5ley1 ( enorm\s p[]4 ,x consi/s ( two p]man5t magnets1 f :i* ! induction is obta9$2 ea* ( ^! is =m$ ( ?irty horse%oe /eel magnets1 two feet & a half long1 & f f\r to five in*es broad1 & ea* is surr\nd$ by a coil ( wire six miles long1 coat$ ) silk to insulate ! coils4 ,a %ock f ^! wires w\ld be in/antane\s dea?4 ,?is app>atus w ultimately be employ$ to s5d a /ream ( electricity ?r\gh long subm>9e & subt]rane\s wires2 b a ,volta-electric ma*9e has hi!rto be5 us$1 9 :i* ! electricity is g5]at$ by a galvanic batt]y in/ead ( magnets4 ,induction1 or ! effect ( ! spiral wires 9 augm5t+ ! p[] ( ,voltaic electricity1 is admirably illu/rat$ 9 ! ,atlantic telegraph4 ,wires t are to convey electricity "u gr\nd1 or ?r\gh wat]1 mu/ be def5d$ f injury & insulat$ to prev5t ! lat]al escape ( ! electricity4 ,= t purpose ! cable t is laid at ! bottom ( ! ,atlantic1 f ne> ,val5tia 9 ,irel& to ,tr9ity ,bay 9 ,newf\ndl&1 is =m$ ( sev5 f9e copp] wires :i* convey ! electricity1 b\nd toge!r by a coat+ ( gutta p]*a1 ov] :i* !re are lay]s ( clo? dipp$ 9 pit*1 & !n ! :ole is cov]$ by /eel wires twi/$ toge!r 9 /r&s & tw9$ r\nd 9 long close spirals1 =m+ a cord or cable n m ?an an in* & a qu>t] 9 diamet]1 & #bajj miles long4 ,! use ( ! gutta p]*a is to insulate ! wires2 ! o!r coat+s are m]ely = protection4 ,! ,voltaic batt]y :i* g5]ates ! electricity consi/s ( #dj cells1 ! plates ( :i* are alt]nately ( z9c & plat9iz$ silv]1 ea* ab\t n9e in*es squ>e1 ! excit+ fluid be+ dilute sulphuric acid4 ,al?\gh ! =ce develop$ by ?is batt]y is s great t a piece ( iron ?ree in*es long & ?ree eigh?s ( an in* 9 diamet] plac$ 9 contact ) ! poles may be consum$ 9 a few m9utes1 x is absolutely incapable ( s5d+ a curr5t ( electricity ?r\gh wires #bejj miles long1 on acc\nt ( _! resi/ance1 )\t ! aid ( ,dr4 ,f>aday's inductive action4 ,x is only ! prim>y ag5t = induc+ a curr5t ( suffici5t /r5g?4 ,to accompli% t1 _m ?\s& y>ds ( f9e copp] wire coat$ ) silk are w\nd r\nd a holl[ s(t iron cyl9d]2 ! :ole is !n coat$ by gutta p]*a1 & ! end ( ! wire is jo9$ to ! wires 9 ! cable s z to =m a cont9u\s l9e f ,val5tia to ,newf\ndl&4 ,a second copp] wire1 %ort] b ?ick] ?an ! prec$+1 & also insulat$ by a coat+ ( silk1 is w\nd r\nd ! cyl9d] above ! gutta p]*a3 :5 ! ends ( ?is ?ick wire are br\ght into contact ) ! poles ( ! batt]y1 curr5ts ( electricity fl[ ?r\gh x1 betwe5 pole & pole1 & 9 _! passage tempor>ily conv]t ! holl[ iron cyl9d] into a p[]ful electro-magnet1 :i* by its reaction induces a curr5t ( electricity 9 ! f9e wire ( suffici5t p[] to cross ! ,atlantic4 ,! effici5cy ( ! electric telegraph dep5ds ^u ! p[] we possess ( break+ & r5ew+ ! curr5t at pleasure1 s9ce by t means di/9ct & successive signals are made f /ation to /ation4 ,9 ! ,atlantic cable positive & negative electricity are transmitt$ alt]nately2 ! electricity is s5t to ,am]ica f alt]nate poles1 & ! curr5t returns aga9 ?r\gh ! wat]1 :i* completes ! circuit4 ,! passage ( electricity ?r\gh a cable or telegraphic wire 9 air is s5sibly in/antane\s2 t ?r\gh a cable1 :e!r ext5d$ 9 wat] or "u gr\nd1 requires "t on acc\nt ( lat]al induction ?r\gh ! gutta p]*a2 = ! electricity1 9 pass+ ?r\gh ! wires1 induces ! opposite electricity on ! surface ( ! wat] or moi/ e>? 9 contact ) ! cable1 & 9 t respect x is precisely l a ,leyd5 j>1 ! gutta p]*a repres5t+ ! glass4 ,z ! p[] ( induction is proportional to ! t5sion ( ! electricity1 & z ! t5sion is cont9ually dim9i%$ by ! resi/ance ( ! wires1 ! induction is cont9ually dim9i%$ & requires a long] "t4 ,electricity took two seconds to pass ?r\gh a cable #gfh miles long1 laid "u gr\nd f ,london to ,man*e/]1 & back aga9 twice2 :ile 9 air x 0 all b in/antane\s1 because ! inductive capacity ( air is v mu* less ?an t ( wat] or moi/ e>?4 ,9 ! exp]im5t ) ! cable "u gr\nd x took two-?irds ( a second to ov]come ! resi/ance ( ! wires1 & !n ! velocity ( ! electricity 0 #ajjj miles 9 a second1 & x 0 ! same :atev] ! int5sity ( ! electricity4 ,x has already be5 m5tion$ t ! effici5cy ( ! electric telegraph dep5ds ^u ! break+ & r5ew+ ! curr5t ( electricity by means ( :i* a succession ( waves ( electricity are s5t ?r\gh ! conduct+ wires4 ,n[ x has be5 asc]ta9$ t ?ree electric waves may travel simultane\sly ?r\gh ! wires ( ! ,atlantic telegraph ) suffici5t int]vals betwe5 !m to record ! indications !y are int5d$ to convey2 t is1 ?ree signals c be intelligibly & practically transmitt$ 9 two seconds4 ,! orig9al design1 /ructure1 & difficulty ( deposit+ ! cable are only equall$ by ! tal5t & p]sev]ance ) :i* x has be5 done4 ,! #e? ( ,augu/1 #aheh1 w be memorable = ! accompli%m5t ( ! bolde/ ent]prise t ev] 0 und]tak5 by man1 & :i* is only ! beg9n+ ( a va/ subm>9e communication t w ultimately encircle ! globe4 ,x has be5 grant$ to ,briti% g5ius ?us to annihilate "t & space1 9 ord] to connect all mank9d into "o great family = _! moral & religi\s advancem5t2 &1 :atev] may be ! fate ( ! ,briti% ,isl&s 9 ! c\rse ( ages1 to _! en]getic race ! glory w rema9 ( hav+ be5 ! *ief in/rum5ts 9 ! h&s ( ,provid5ce = ! civilization ( ! _w--a civilization :i* w ext5d ) ! developm5t ( _! num]\s colonies into great indep5d5t ,*ri/ian /ates1 l ^? ( ! ,union 9 ,nor? ,am]ica4 ,! ?und]bolt snat*$ f heav5 by ,frankl9 n[ passes ?r\gh ! dep?s ( ! ,atlantic z a mess5g] ( peace betwe5 ! k9dr$ nations4#af ,9 telegraphs on l& ! int5sity ( ! batt]y or magnets is increas$ by induction on ! same pr9ciple4 ,x is by int5sity t ! electric curr5t is enabl$ to pass ?r\gh ! wires1 & t is augm5t$ by increas+ ! numb] ( coils r\nd ! cyl9d]3 h[ev]1 x is only advantage\s :5 ! di/ance betwe5 ! /ations is great1 = !n ! resi/ance 9 ! additional coils be>s a small proportion to ! resi/ance (f]$ by v long wires1 b a v great proportion to t oppos$ 9 v %ort ones4 ,! nice adju/m5t = ea* case has be5 det]m9$ by ! exp]im5ts ( em95t electricians1 & all ! arrangem5ts h be5 br\ght to great p]fection 9 ?is wond]ful triumph ( sci5ce1 :i* is due to ,volta1 :o call$ into exi/5ce ! fi]y /ream1 & to ,f>aday1 :o has giv5 x ! en]gy ( ! lightn+4 ,:5 ! l5g? ( ! wire 9 ! helices ( an electro-magnet is v great1 x (f]s increas+ resi/ance to ! passage ( ! electricity1 s t ! cessation ( magnetism is n in/antane\s :5 ! contact ) ! ,voltaic batt]y is brok54 ,to rem$y t defect an in/rum5t has be5 inv5t$ :i* in/antane\sly deprives ! app>atus ( ! rema9+ electricity4 ,a great l5g? ( f9e wire gives ! sev]e/ %ocks1 :ile a %ort] & ?ick] wire gives ! longe/ sp>ks & ignites ! greate/ quantity ( plat9um wire4 ,ruhmkorff's electro-inductive app>atus has ei!r be5 improv$1 or new ma*9es con/ruct$1 by ,messrs4 ,grove1 ,gassiot1 & ,j\le1 ( int5se en]gy4 ,inde$1 s great is ! en]gy ( electro-induction1 t hopes 7 ent]ta9$ ( its sup]s$+ /eam z a motive p[]4 ,= ! curr5t ( electricity f an electro-magnet c be made to fl[ 9 opposite directions1 s z to produce alt]nate attractions & repulsions1 & consequ5tly a cont9u$ motion1 :i* might be appli$ z a motive =ce to ma*9]y4 ,h[ev]1 ,mr4 ,j\le has prov$ t ! p[] develop$ by "o p\nd ( coal 9 combu/ion is to t produc$ by "o p\nd ( z9c consum$ 9 ,mr4 ,grove's p[]ful electro-magnetic app>atus z n9e to "o1 s t1 ev5 if z9c 7 z *eap z coal1 & a ,voltaic batt]y z easily kept 9 ord] z an eng9e-furnace1 electricity w n sup]s$e /eam z a motive p[]4 ,a curr5t ( electricity trav]s+ a conductor gives out a quantity ( heat det]m9$ by fix$ laws1 ! am\nt ( :i* is inv>iable z long z ! ma*9e to :i* x is appli$ rema9s at re/2 b ! in/ant ! ma*9e is set 9 motion a reaction takes place 9 ! int5sity ( ! curr5t1 caus+ a dim9ution 9 ! quantity ( heat1 because ! heat t disappe>s is conv]t$ into ! me*anical =ce ex]t$ by ! eng9e4 ,mr4 ,j\le's exp]im5ts prove t1 :5ev] a curr5t ( electricity is g5]at$ by a magneto-electric ma*9e1 ! quantity ( heat evolv$ by t curr5t has a con/ant relation to ! p[] requir$ to "w ! ma*9e2 & on ! o!r h&1 :5ev] an eng9e is work$ by a ,voltaic batt]y1 t ! p[] develop$ is at ! exp5se ( ! calorific =ce ( ! batt]y = a giv5 consumption ( z9c1 ! me*anical effect produc$ hav+ a fix$ relation to ! heat lo/ 9 ! ,voltaic curr5t4 ,! obvi\s conclusion ,mr4 ,j\le draws f ^! exp]im5ts is1 t heat & me*anical p[] are conv]tible into "o ano!r1 & x becomes evid5t1 !re=e1 t heat is ei!r ! vis viva or liv+ =ce ( pond]able p>ticles1 or a /ate ( attraction & repulsion capable ( g5]at+ vis viva 7,n4 #bbb74 ,,section ,,xxxiii4 ,electricity produc$ by ,rotation--,direction ( ! ,curr5ts--,electricity f ! ,rotation ( a ,magnet--,m4 ,arago's ,exp]im5t expla9$--,rotation ( a ,plate ( ,iron betwe5 ! ,poles ( a ,magnet--,relation ( ,sub/ances to ,magnets ( ?ree ,k9ds--,!rmo-,electricity4 ,m4 ,,arago discov]$ a s\rce ( magnetism 9 rotatory motion4 ,if a circul> plate ( copp] be made to revolve imm$iately above or bel[ a magnetic ne$le or magnet1 susp5d$ 9 su* a mann] t x may rotate 9 a plane p>allel to t ( ! copp] plate1 ! magnet t5ds to foll[ ! circumvolution ( ! plate2 or1 if ! magnet revolves1 ! plate t5ds to foll[ its motion2 s p[]ful is ! effect1 t magnets & plates ( _m p\nds weight h be5 c>ri$ r\nd4 ,?is is q indep5d5t ( ! motion ( ! air1 s9ce x is ! same :5 a pane ( glass is int]pos$ betwe5 ! magnet & ! copp]4 ,:5 ! magnet & ! plate are at re/1 n ! smalle/ effect1 attractive1 repulsive1 or ( any k9d1 c be p]ceiv$ betwe5 !m4 ,9 describ+ ?is ph5om5on1 ,m4 ,arago /ates t x takes place n only ) metals1 b ) all sub/ances1 solids1 liquids1 & ev5 gases1 al?\gh ! int5sity dep5ds ^u ! k9d ( sub/ance 9 motion4 ,exp]im5ts made by ,dr4 ,f>aday expla9 ?is s+ul> action4 ,he f\nd t1 if a piece ( metal or a metallic wire =m+ a circuit ( any =m be mov$ f "r to left across ! l9es ( =ce proce$+ f ! pole ( a b> magnet1 ^! l9es ( =ce induce a curr5t ( electricity fl[+ 9 "o direction2 & :5 ! motion ( ! metal or wire is rev]s$1 ! direction ( ! curr5t is rev]s$ also3 ! rotation ( ! magnet ab\t its axis has no effect on ^! results1 & no curr5t is induc$ :5 ! metal or wire is at re/4 ,a plate ( copp]1 twelve in*es 9 diamet] & "o fif? ( an in* ?ick1 0 plac$ betwe5 ! poles ( a p[]ful horse%oe magnet1 consequ5tly cross+ ! magnetic l9es ( =ce at "r angles1 & connect$ at c]ta9 po9ts ) a galvanomet] by copp] wires4 ,:5 ! plate 0 at re/ no effect 0 produc$2 b z soon z ! plate 0 made to revolve rapidly ! galvanomet] ne$le 0 deflect$ sometimes z mu* z #ij1 & by a uni=m rotation ! deflection 0 con/antly ma9ta9$ at #de4 ,:5 ! motion ( ! copp] plate 0 rev]s$1 ! ne$le 0 deflect$ 9 ! contr>y direction1 & ?us a p]man5t curr5t ( electricity 0 evolv$ by an ord9>y magnet4 ,! int5sity ( ! electricity collect$ by ! wires1 & convey$ by !m to ! galvanomet]1 v>i$ ) ! position ( ! plate relatively to ! poles ( ! magnet4 ,! motion ( ! electricity 9 ! copp] plate may be conceiv$ by consid]+ t1 m]ely by mov+ a s+le wire1 l ! spoke ( a :eel1 be=e a magnetic pole1 a curr5t ( electricity t5ds to fl[ ?r\gh x f "o end to ! o!r4 ,h5ce1 if a :eel be con/ruct$ ( a great _m su* spokes1 & revolv$ ne> ! pole ( a magnet 9 ! mann] ( ! copp] disc1 ea* radius or spoke w t5d to h a curr5t produc$ 9 x z x passes ! pole4 ,n[1 z ! circul> plate is no?+ m ?an an inf9ite numb] ( radii or spokes 9 contact1 ! curr5ts w fl[ 9 ! direction ( ! radii if a *annel be op5 = _! return2 &1 9 a cont9u\s plate1 t *annel is af=d$ by ! lat]al portions on ea* side ( ! p>ticul> radius close to ! magnetic pole4 ,?is hypo!sis is confirm$ by obs]vation2 = ! curr5ts ( positive electricity set f ! c5tre to ! circumf]5ce1 & ! negative f ! circumf]5ce to ! c5tre1 & vice v]s1 accord+ to ! position ( ! magnetic poles & ! direction ( rotation2 s t a collect+ wire at ! c5tre ( ! copp] plate conveys positive electricity to ! galvanomet] 9 "o case1 & negative 9 ano!r2 t collect$ by a conduct+ wire 9 contact ) ! circumf]5ce ( ! plate is always ! opposite ( ! electricity convey$ f ! c5tre4 ,x is evid5t t1 :5 ! plate & magnet are bo? at re/1 no effect takes place1 s9ce ! electric curr5ts :i* cause ! deflection ( ! galvanomet] are only induc$ by motion across ! magnetic l9es ( =ce4 ,:5 ! plate is plac$ edgewise s z to be p>allel to ^! l9es ( =ce1 no revolution ( x ) ! mo/ p[]ful magnet produces ! slighte/ signs ( a curr5t at ! galvanomet]4 ,! same ph5om5a may be produc$ by electro-magnets4 ,! effects are simil> :5 ! magnet rotates & ! plate rema9s at re/4 ,:5 ! magnet revolves uni=mly ab\t its own axis1 electricity ( ! same k9d is collect$ at its poles1 & ! opposite electricity at its equator4 ,! ph5om5a :i* take place 9 ,m4 ,arago's exp]im5ts may be expla9$ on ?is pr9ciple4 ,:5 bo? ! copp] plate & ! magnet are revolv+1 ! action ( ! induc$ electric curr5t t5ds cont9ually to dim9i% _! relative motion1 & to br+ ! mov+ bodies into a /ate ( relative re/2 s t1 if "o be made to revolve by an extrane\s =ce1 ! o!r w t5d to revolve ab\t x 9 ! same direction1 & ) ! same velocity4 ,:5 a plate ( iron1 or ( any sub/ance capable ( be+ made ei!r a tempor>y or p]man5t magnet1 revolves betwe5 ! poles ( a magnet1 x is f\nd t dissimil> poles on opposite sides ( ! plate neutralize ea* o!r's effects1 s t no electricity is evolv$2 :ile simil> poles on ea* side ( ! revolv+ plate increase ! quantity ( electricity1 & a s+le pole end-on is suffici5t4 ,b :5 copp]1 & sub/ances n s5sible to ord9>y magnetic impressions1 revolve1 simil> poles on opposite sides ( ! plate neutralize ea* o!r2 dissimil> poles on ea* side exalt ! action2 & a s+le pole at ! edge ( ! revolv+ plate1 or end-on1 does no?+4 ,?is =ms a te/ = di/+ui%+ ! ord9>y magnetic =ce f t produc$ by rotation4 ,if unlike poles1 t is1 a nor? & s\? pole1 produce m effect ?an "o pole1 ! =ce w be due to electric curr5ts2 if simil> poles produce m effect ?an "o1 !n ! p[] is n electric4 ,^! inve/igations %[ t !re are really v few bodies magnetic 9 ! mann] ( iron4 ,dr4 ,f>aday !re=e arranges sub/ances 9 ?ree classes1 ) reg>d to _! relation to magnets3--^? affect$ by ! magnet :5 at re/1 l iron1 /eel1 & nickel1 :i* possess ord9>y magnetic prop]ties2 ^? affect$ :5 9 motion1 9 :i* electric curr5ts are evolv$ by ! inductive =ce ( ! magnet1 su* z copp]2 &1 la/ly1 ^? :i* are p]fectly indiff]5t to ! magnet1 :e!r at re/ or 9 motion4 ,x has already be5 obs]v$ t ?ree bodies are requisite to =m a galvanic circuit1 "o ( :i* mu/ be fluid4 ,b1 9 #ahbb1 ,pr(essor ,seebeck1 ( ,b]l91 discov]$ t electric curr5ts may be produc$ by ! p>tial application ( heat to a circuit =m$ ( two solid conductors4 ,= example1 :5 a semicircle ( bismu?1 jo9$ to a semicircle ( antimony1 s z to =m a r+1 is heat$ at "o ( ! junctions by a lamp1 a curr5t ( electricity fl[s ?r\gh ! circuit f ! antimony to ! bismu?2 & su* !rmo-electric curr5ts produce all ! electro-magnetic effects4 ,a compass ne$le1 plac$ ei!r )9 or )\t ! circuit1 & at a small di/ance f x1 is deflect$ f its natural position1 9 a direction correspond+ to ! way 9 :i* ! electricity is fl[+4 ,if su* a r+ be susp5d$ s z to move easily 9 any direction1 x w obey ! action ( a magnet br\ght ne> x1 & may ev5 be made to revolve4 ,accord+ to ! rese>*es ( ,m4 ,seebeck1 ! same sub/ance1 unequally heat$1 exhibits electrical curr5ts2 & ,m4 ,nobili obs]v$1 t 9 all metals1 except z9c1 iron1 & antimony1 ! electricity fl[s f ! hot "p t[>ds t :i* is cold4 ,t philosoph] attributes t]re/rial magnetism to a diff]5ce 9 ! action ( heat on ! v>i\s sub/ances ( :i* ! cru/ ( ! e>? is compos$2 &1 9 confirmation ( 8 views1 he has produc$ electrical curr5ts by ! contact ( two pieces ( moi/ clay1 ( :i* "o 0 hott] ?an ! o!r4 ,m4 ,becqu]el con/ruct$ a !rmo-electric batt]y ( "o k9d ( metal1 by :i* he has det]m9$ ! relation betwe5 ! heat employ$ & ! int5sity ( ! result+ electricity4 ,he f\nd t1 9 mo/ metals1 ! int5sity ( ! curr5t increases ) ! heat to a c]ta9 limit1 b t ?is law ext5ds mu* f>!r 9 metals t are difficult to fuse1 & :i* d n ru/4 ,! exp]im5ts ( ,pr(essor ,cumm+ %[ t ! mutual action ( a magnet & a !rmo-electric curr5t is subject to ! same laws z ^? ( magnets & galvanic curr5ts2 consequ5tly all ! ph5om5a ( repulsion1 attraction1 & rotation may be exhibit$ by a !rmo-electric curr5t4 ,m4 ,botto1 ( ,tur91 has decompos$ wat] & "s solutions by !rmo-electricity2 & ! ,cav4 ,ant9ori ( ,flor5ce succe$$ 9 obta9+ a brilliant sp>k ) ! aid ( an electro-dynamic coil4 ,! pr9ciple ( !rmo-electricity has be5 employ$ by ,,mm4 ,nobili & ,melloni = measur+ extremely m9ute quantities ( heat 9 _! exp]im5ts on ! in/antane\s transmission ( radiant heat4 ,! !rmo-multipli]1 :i* !y con/ruct$ = t purpose1 consi/s ( a s]ies ( alt]nate b>s1 or r f9e wires ( bismu? & antimony1 plac$ side by side1 & ! extremities alt]nately sold]$ toge!r4 ,:5 heat is appli$ to "o end ( ?is app>atus1 ! o!r rema9+ at its natural temp]ature1 curr5ts ( electricity fl[ ?r\gh ea* pair ( b>s1 :i* are convey$ by wires to a delicate galvanomet]1 ! ne$le ( :i* po9ts out ! int5sity ( ! electricity convey$1 & consequ5tly t ( ! heat employ$4 ,?is in/rum5t is s delicate t ! comp>ative w>m? ( diff]5t insects has be5 asc]ta9$ by means ( x4 ,! cons]vation ( =ce is /rictly ma9ta9$ ?r\gh\t ! :ole sci5ce & diff]5t =ms ( electricity4 ,9 /atic electricity ! positive & negative =ces exactly balance "o ano!r2 !y are always simultane\s1 & relat$ (t5 by curv$ l9es ( =ce2 !re is no defect or surplus1 & ! exi/5ce ( "o k9d )\t ! o!r is utt]ly impossible--x is absolutely a dual =ce4 ,! v same may be said ( electric curr5ts1 :e!r produc$ by ! ,voltaic batt]y or 9 any o!r way--! curr5t 9 "o "p ( ! circuit is absolutely ! same 9 am\nt & dual "* z ! o!r2 & 9 ! insulat$ ,voltaic batt]y1 :]e ! su/a9+ p[] is int]nal1 n ! slighte/ developm5t ( ! =ces ( ei!r ( ^! c occur till ! circuit is complet$ or induction all[$ at ! extremities2 = if :5 !re is no circuit ! induction be prev5t$1 n m]ely no curr5t1 b no quantity ( electricity at ! poles ready to produce a curr5t1 c be evolv$ 9 ! slighte/ degree4#ag ,,section ,,xxxiv4 ,magnetism a ,dual ,p[]--,anti!tic ,"* ( ,p>amagnetism & ,diamagnetism--,! ,e>? ,p>amagnetic--,prop]ties ( ,p>amagnetic ,bodies--,pol>ity--,induction--,l9es ( ,magnetic ,=ce--,curr5ts ( ,electricity induc$ by !m--,prov$ to be ,clos$ ,curves--,analogy & ,id5tity ( ,electricity & ,magnetism--,t]re/rial ,magnetism--,mean ,values ( ! ,?ree ,magnetic ,elem5ts--,_! ,v>iations 9 ,d\ble ,progression prov$ to consi/ ( ,two ,sup]pos$ ,v>iations--,discov]y ( ! ,p]iodicity ( ! ,magnetic ,/orms--,! ,dec5nial ,p]iod ( ! ,magnetic ,elem5ts ! same ) t ( ! ,sol> ,spots--,magnetism ( ! ,atmosph]e--,diamagnetism--,action ( ,electro-,magnetism on ,p>amagnetic1 ,diamagnetic ,bodies1 & on ,copp]1 v diff]5t--,pro( ( ,diamagnetic ,pol>ity & ,induction--,magnecry/allic ,action--,effects ( ,compression1 ,heat1 & ,cleavage on ,magnetic ,bodies--,mutual ,dep5d5ce ( ,light1 ,heat1 ,electricity1 c4 c4--,! ,cons]vation ( ,=ce & ! ,p]man5cy ( ,matt] ,prim>y ,laws ( ,nature--,def9ition ( ,gravity n accord+ to t ,law--,gravity only ! ,residual ,=ce ( a ,univ]sal ,p[]--,magnetism ( ! ,e!real ,m$ium4 ,,magnetism may be reg>d$ z a new sci5ce 9 consequ5ce ( ! pr(\nd rese>*es & admirable discov]ies ( ,dr4 ,f>aday4 ,s9ce ! magnetism ( matt] is only kn[n by ! action ( a magnet or ( electricity ^u x1 by us+ an extremely en]getic magnet or electro-magnet he has prov$ t all kn[n sub/ances1 :e!r solid1 liquid1 or ari=m1 are m or less magnetic1 b t ! magnetism is v diff]5t 9 diff]5t sub/ances4 ,= example1 if a b> ( iron be freely susp5d$ betwe5 ! poles ( a v p[]ful magnet or electro-magnet1 x w be attract$ by bo? poles1 & w set or re/ 9 ! direction ( a /raight l9e jo9+ !m2 b if a simil> b> ( bismu? be freely susp5d$ 9 ! same mann]1 x w re/ 9 a direction at "r angles to t :i* ! iron b> assum$4 ,?us ! direction 9 :i* ! iron sets is axial or 9 ! l9e ( =ce1 :ile t :i* ! bismu? assumes is equatorial or p]p5dicul> to ! l9e ( =ce4 ,sub/ances t are magnetic aft] ! mann] ( iron are said to be p>amagnetic1 ^? t are magnetic aft] ! mann] ( bismu? are diamagnetic4 ,z f> z we "k1 all matt] comes "u "o or o!r ( ^! laws4 ,_m bodies are p>amagnetic besides iron1 z ! load/one1 :i* consi/s ( ! p]oxide & protoxide ( iron mix$ ) small portions ( silica & alum9a2 also "s ( ! gems & metals1 z cobalt1 nickel1 c4 ,a sub/ance is (t5 p>amagnetic if x conta9s only ! #acj1jjj? "p ( its weight ( iron2 b by f> ! great] numb] are diamagnetic1 z all animal & vegetable matt]1 acids1 oils1 sug>1 />*1 bread1 c41 & all ! gases except oxyg51 :i* is highly p>amagnetic2 & its =ce increases ) its d5sity3 b not)/&+ ! pr$om9ance ( diamagnetic matt] at ! surface1 ! t]re/rial globe is p>amagnetic--9 fact x is a p[]ful magnet4 ,besides ! sub/ances :i* are p>amagnetic naturally1 t prop]ty may be imp>t$ by a v>iety ( me?ods1 z by friction ) magnets or ev5 juxtaposition ) !m2 & a b> ( h>d /eel held at ! angle ( ! dip w become a magnet on receiv+ a few /rokes ) a hamm] on its upp] end4 ,pol>ity is "o ( ! mo/ di/+ui%+ *>act]s ( magnetism3 x is ! prop]ty :i* a magnet possesses :5 freely susp5d$ ( re/+ spontane\sly 9 ! magnetic m]idian1 or ne>ly nor? & s\?1 & always return+ to t position :5 di/urb$ 9 consequ5ce ( ! mean magnetic attraction ( ! e>?2 yet ! magnet has no t5d5cy to move to ! nor? or s\? ev5 :5 float+ on wat]1 because ! same pole t attracts "o end repels ! o!r4 ,bo? poles ( a magnet attract iron1 :i* 9 return attracts ei!r pole ( ! magnet ) an equal & contr>y =ce4 ,! action ( a magnet on unmagnetis$ iron is conf9$ to attraction1 :]eas ! reciprocal ag5cy ( magnets is *>act]is$ by a repulsive z well z by an attractive =ce2 = a nor? pole repels a nor? pole1 & a s\? pole repels a s\? pole2 b a nor? & s\? pole mutually attract "o ano!r--:i* proves t p>amagnetism is a dual p[] 9 :i* ! cons]vation ( =ce is p]fectly ma9ta9$1 = ! =ce ( attraction is exactly equal to ! =ce ( repulsion4 ,"o k9d ( pol>ity _c exi/ )\t ! o!r3 !y are absolutely simultane\s1 dep5d5t1 & ( equal int5sity4 ,induction is ! p[] :i* a magnet possesses ( excit+ tempor>y or p]man5t p>amagnetism 9 su* bodies 9 its vic9ity z are capable ( receiv+ x4 ,by ?is prop]ty ! m]e approa* ( a magnet r5d]s iron & /eel p>amagnetic1 ! m p[]fully ! less ! di/ance1 b ! induc$ =ce is always exactly equal to ! =ce :i* produces x4 ,:5 ! nor? end ( a magnet is br\ght ne> to1 & 9 ! l9e )1 an unmagnetis$ iron b>1 ! b> acquires all ! prop]ties ( a p]fect magnet2 ! end next ! nor? pole ( ! magnet becomes a s\? pole1 :ile ! remote end becomes a nor? pole4 ,exactly ! rev]se takes place :5 ! s\? end is pres5t$ to ! b>1 s t ea* pole ( a magnet induces ! opposite pol>ity 9 ! adjac5t end ( ! b>1 & ! same pol>ity 9 ! remote extremity2 consequ5tly ! ne>e/ extremity ( ! b> is attract$1 & ! f>!r repell$2 b z ! action is great] on ! adjac5t ?an on ! di/ant "p1 ! result+ =ce is t ( attraction4 ,by induction ! iron b> n only acquires pol>ity1 b ! p[] ( induc+ p>amagnetism 9 a ?ird body2 & al?\gh all ^! prop]ties vani% f ! iron z soon z ! magnet is remov$1 a la/+ increase ( int5sity is g5]ally imp>t$ to ! magnet itself by ! reaction ( ! tempor>y p>amagnetism ( ! iron4 ,iron acquires ! inductive =ce m rapidly ?an /eel1 yet x loses x z quickly on ! removal ( ! magnet1 :]eas ! /eel is impress$ ) a la/+ pol>ity4 ,a c]ta9 "t is requisite = induction1 & x may be accel]at$ by any?+ t excites a vibratory motion 9 ! p>ticles ( ! /eel2 su* z ! sm>t /roke ( a hamm]1 or heat succe$$ by sudd5 cold4 ,a /eel b> may be conv]t$ into a magnet by ! transmission ( an electric dis*>ge ?r\gh x2 & z its efficacy is ! same 9 :atev] direction ! electricity passes1 ! effect arises f its me*anical op]ation excit+ a vibration among ! p>ticles ( ! /eel4 ,x has be5 obs]v$ t ! p>ticles ( iron easily resume _! neutral /ate aft] induction1 :ile ^? ( /eel resi/ ! re/oration ( equilibrium1 or a return to ! neutral /ate3 x is !re=e evid5t t any cause :i* removes or dim9i%es ! resi/ance ( ! p>ticles w t5d to de/roy ! p>amagnetism ( ! /eel2 consequ5tly ! same me*anical means :i* develop ! p[] w also de/roy x4 ,on t acc\nt a /eel b> may lose its p>amagnetism by any me*anical concussion1 su* z by fall+ on a h>d sub/ance1 a bl[ ) a hamm]1 & heat+ to r$ness1 :i* makes ! /eel s(t4 ,! circum/ances :i* det]m9e :e!r x %all ga9 or lose are its position ) respect to ! magnetic equator1 & ! high] or l[] int5sity ( its previ\s magnetic /ate4 ,a comp>ison ( ! numb] ( vibrations accompli%$ by ! same magnetis$ ne$le dur+ ! same "t at diff]5t di/ances f a magnet gives ! law ( p>amagnetic int5sity1 :i* foll[s ! inv]se ratio ( ! squ>e ( ! di/ance--a law t is n affect$ by ! int]v5tion ( any sub/ance :atev] betwe5 ! magnet & ! ne$le1 provid$ ! sub/ance be n itself susceptible ( magnetism4 ,induction & ! reciprocal action ( magnets are !re=e subject to ! laws ( me*anics2 b ! composition & resolution ( ! =ces are complicat$ 9 consequ5ce ( f\r =ces be+ con/antly 9 activity1 two 9 ea* magnet4 ,mr4 ,7 ,fox discov]$ t ! law ( ! p>amagnetic =ce *anges f ! inv]se squ>e ( ! di/ance to ! simple inv]se ratio :5 ! di/ance betwe5 two magnets is z small z f ! f\r? to ! eigh? ( an in*1 or ev5 z mu* z half an in* :5 ! magnets are l>ge2 & 9 ! case ( repulsion1 t ! *ange takes place at a /ill great] di/ance1 especially :5 ! two magnets diff] mat]ially 9 int5sity4 ,)\t assum+ any hypo!sis ( :at magnetism is1 or h[ t =ce is orig9at$ or su/a9$1 ,dr4 ,f>aday reg>ds a magnet z a s\rce ( p[] surr\nd$ by curv$ l9es ( =ce :i* are n only repres5tants ( ! magnetic p[] 9 quality & direction1 b also 9 quantity--an hypo!sis :i* accords p]fectly ) exp]im5t1 & ) ! action bo? ( electricity & magnetism4 ,! nature & =m ( ^! l9es may be se5 by plac+ a b> magnet ^u a table1 spread+ a %eet ( /iff pap] ov] x s z to be p]fectly level & free f creases1 & !n sift+ v clean iron fil+s ?r\gh a f9e sieve equably ov] x4 ,! fil+s w in/antly assume ! =m ( ! curv$ l9es repres5t$ by fig4 #a1 plate #g1 9 consequ5ce ( ! action ( ! magnet4 ,^! l9es are ! true repres5tatives ( ! magnetic =ces1 & be+ relat$ to a pol> p[]1 !y h opposite qualities 9 opposite directions4 ,:5 a magnet is brok5 across ! middle1 ea* "p is at once conv]t$ into a p]fect magnet2 ! "p t orig9ally _h a s\? pole acquires a nor? pole at ! fractur$ end2 ! "p t _h orig9ally a nor? pole gets a s\? pole2 & z f> z me*anical division c be c>ri$1 x is f\nd t ea* fragm5t is a p]fect magnet4 ,fig4 #b1 plate #g1 %[s ! l9es ( =ce 9 a fractur$ magnet :5 ! ends are n yet sep>at$2 fig4 #c %[s !m :5 !y are4 ,curr5ts ( electricity are produc$ 9 conduct+ bodies mov$ across ^! l9es ( magnetic =ce4 ,if a copp] wire at a little di/ance above ! nor? pole ( a b> magnet be mov$ f left to "r1 at any angle across ! l9es ( magnetic =ce1 !y w induce a curr5t ( electricity 9 ! wire fl[+ f "r to left2 if ! wire be mov$ ) ! same velocity 9 ! contr>y direction1 ! induc$ curr5t w be ( equal int5sity1 b x w fl[ f left to "r4 ,simil> results are obta9$ f ! s\? pole1 & ! ph5om5a are ! same :5 ! magnet is mov$ & ! wire is at re/2 9 bo? cases ! int5sity is great] ! swift] ! motion4 ,x appe>s t ! quantity ( electricity induc$ is directly z ! am\nt ( ! magnetic curves int]sect$1 & :5 a wire is mov+ uni=mly 9 a field ( equal magnetic =ce1 ! curr5t ( electricity g5]at$ is proportional to ! "t1 & also to ! velocity ( motion2 = :5 a metallic disc is made to revolve ?r\gh ! l9es ( =ce1 ! curr5t induc$ is /ronge/ ne> ! edge :]e ! velocity is greate/2 & 9 diff]5t sub/ances mov+ across ! l9es ( =ce ! int5sity ( ! induc$ curr5t is directly z ! conduct+ p[] ( ! sub/ance4 ,?us bodies mov$ ne> a magnet h an electrical curr5t develop$ 9 !m1 & conv]sely bodies affect$ by an electric curr5t are def9itely mov$ by a magnet ne> !m4 ,by ! prec$+ exp]im5ts x appe>s t magnetic pol>ity is manife/$ 9 two ways2 9 ! magnetis$ ne$le1 by attraction & repulsion1 & 9 a wire mov+ across l9es ( magnetic =ce x is %[n by ! opposite directions 9 :i* ! induc$ curr5t fl[s accord+ z ! body is mov$ f ! "r to ! left1 or left to "r4 ,h5ce pol>ity consi/s 9 ! opposite & anti!tical actions manife/$ at ! opposite ends or opposite sides ( a limit$ or unlimit$ l9e ( =ce4 ,anti!sis is ! true & mo/ g5]al "* ( magnetism1 :atev] may be its mode ( action4 ,x 0 by ! induction ( electric curr5ts 9 copp] wires mov+ across ! l9es ( magnetic =ce t ,dr4 ,f>aday prov$ t ! l9es ( =ce issu+ f a magnet are clos$ curves :i* return aga9 & pass ?r\gh ! int]ior ( ! magnet4 ,he plac$ two b> magnets ( ! same l5g?1 size1 & int5sity ) _! simil> poles toge!r1 s t !y might act z "o magnet4 ,a copp] wire 0 !n pass$ betwe5 _! axes1 :i* aft] ext5d+ ?r\gh half _! l5g? 0 b5t up equatorially & turn$ back along ! outside1 s t ! :ole wire =m$ a loop1 ! two ends be+ connect$ ) a galvanomet]4 ,:5 ! :ole wire 0 made to revolve1 no effect 0 produc$1 al?\gh x cross$ ! l9es ( magnetic =ce2 b :5 x 0 cut 9 two1 s z to sep>ate ! ext]nal f ! int]nal "p1 electrical curr5ts ( equal int5sity1 b 9 contr>y directions1 7 induc$ 9 ea* portion ( ! wire z !y 7 made sep>ately to cross ! l9es ( =ce1 = ! app>atus 0 s con/ruct$ t t c\ld be done4 ,! ext]ior wire cross$ ! l9es ( =ce :i* issu$ f ! magnets at "r angles to _! axes1 :ile ! equatorial "p ( ! int]ior wire trav]s$ ! return+ l9es ( =ce4 ,x is evid5t t ^! =ces neutraliz$ ea* o!r :5 ! :ole wire revolv$3 consequ5tly ! int]nal & ext]nal l9es ( =ce mu/ h be5 ( equal int5sity & opposite 9 direction1 s z to balance "o ano!r4 ,by ?is & a v great numb] ( o!r exp]im5ts ,dr4 ,f>aday has prov$ t ! magnetic l9es ( =ce are cont9u\s clos$ curves alike 9 %ape1 size1 & p[]4 ,!y ext5d indef9itely beyond ! magnet1 & und]go no *ange by di/ance4 ,?us ! magnetic =ce p]vades ! int]ior ( ! mass2 if electricity does ! same1 a comp5sation mu/ ei!r take place1 or x also mu/ move 9 l9es ( =ce1 s5sible only at ! surface4 ,electricity has a p]petual t5d5cy to escape1 & does escape1 :5 n prev5t$ by ! co]cive p[] ( ! air1 & o!r non-conduct+ sub/ances4 ,su* a t5d5cy does n exi/ 9 magnetism1 :i* nev] leaves ! sub/ance conta9+ x "u any circum/ances :atev]4 ,!re mu/ be "s co]cive =ce1 analog\s to friction1 :i* arre/s ! magnetic =ces1 s z fir/ to oppose _! sep>ation1 & !n to prev5t _! reunion4 ,9 s(t iron ! co]cive =ce is ei!r want+ or extremely feeble1 s9ce iron is easily r5d]$ p>amagnetic by induction1 & z easily loses t quality2 :]eas 9 /eel ! co]cive =ce is extremely en]getic1 because x prev5ts ! /eel f acquir+ ! p>amagnetic prop]ties rapidly1 & entirely h9d]s x f los+ !m :5 acquir$4 ,! feebl5ess ( ! co]cive =ce 9 iron1 & its en]gy 9 /eel1 ) reg>d to ! p>amagnetic =ce1 is p]fectly analog\s to ! facility ( transmission af=d$ to electricity by non-electrics1 & ! resi/ance x exp]i5ces 9 electrics4 ,at e /ep ! analogy betwe5 electricity & magnetism becomes m /rik+4 ,! ag5cy ( attraction & repulsion is common to bo?2 ! positive & negative electricities are simil> to ! nor!rn & s\!rn pol>ities1 & are gov]n$ by ! same laws--namely1 t betwe5 l p[]s !re is repulsion1 & betwe5 unlike p[]s !re is attraction4 ,ea* ( ^! f\r =ces is capable ( act+ mo/ en]getically :5 alone2 b z ! electric equilibrium is re/or$ by ! union ( ! two electric /ates1 & magnetic neutrality by ! comb9ation ( ! two pol>ities1 !y respectively neutralise ea* o!r :5 jo9$4 ,all ^! =ces v>y inv]sely z ! squ>e ( ! di/ance1 & consequ5tly come "u ! same me*anical laws4 ,a l analogy ext5ds to magnetic & electric induction4 ,iron & /eel are 9 a /ate ( equilibrium :5 neutral2 b ?is equilibrium is imm$iately di/urb$ on ! approa* ( ! pole ( a magnet1 :i* by induction transf]s "o k9d ( pol>ity to "o end ( an iron or /eel b>1 & ! opposite k9d to ! o!r--effects exactly simil> to electrical induction4 ,!re is ev5 a correspond5ce betwe5 ! fracture ( a magnet & t ( an electric conductor2 = if an oblong conductor be electrifi$ by induction1 its two extremities w h opposite electricities2 & if 9 t /ate x be divid$ across ! middle1 ! two portions1 :5 remov$ to a di/ance f "o ano!r1 w ea* reta9 ! electricity t has be5 induc$ ^u x4 ,! analogy1 h[ev]1 does n ext5d to transf]5ce4 ,a body may transf] a r$undant quantity ( positive electricity to ano!r1 or deprive ano!r ( its electricity--! "o ga9+ at ! exp5se ( ! o!r2 b a body _c possess only "o k9d ( pol>ity4 ,) t exception1 !re is su* p]fect correspond5ce betwe5 ! !ories ( magnetic attractions & repulsions1 & electric =ces 9 conduct+ bodies1 t !y n only are ! same 9 pr9ciple1 b are det]m9$ by ! same =mul4 ,exp]im5t concurs ) !ory 9 prov+ ! id5tity ( ^! two influ5ces4 ,h5ce1 if ! electrical ph5om5a be due to a modification ( ! e!real m$ium1 ! magnetic ph5om5a mu/ be ow+ to an analog\s cause4 ,curv$ l9es ( magnetic =ce issue f e po9t ( ! e>?'s surface :]e !re is s5sible dip1 & b5d+ r\nd ent] ! e>? aga9 at ! magnetic equator4 ,!y induce electric curr5ts 9 conduct+-wires1 mov+ across !m exactly ! same z 9 artificial magnets2 & :5 a holl[ helix1 or coil ( copp] wire1 ^: extremities are connect$ ) a galvanomet]1 is plac$ 9 ! magnetic dip1 & sudd5ly mov$ across ! l9es ( =ce1 ! ne$le ( ! galvanomet] w vibrate ?r\gh an arc ( #hj or #ij1 9 consequ5ce ( ! electric curr5t induc$ by ^! l9es ( magnetic =ce 9 ! wire1 & ! action is great] :5 a core ( s(t iron is plac$ 9 ! helix1 :i* becomes a tempor>y magnet by induction4 ,aga91 if a copp] plate be connect$ ) a galvanomet] by two copp] wires1 "o f ! c5tre1 & ano!r f ! circumf]5ce1 9 ord] to collect & convey ! electricity1 x is f\nd t1 :5 ! plate is made to revolve 9 a plane pass+ ?r\gh ! l9e ( ! dip1 ! galvanomet] is n affect$4 ,b z soon z ! plate is incl9$ to t plane1 electricity beg9s to be develop$ by its motion across ! l9es ( magnetic =ce2 x becomes m p[]ful z ! incl9ation increases1 & arrives at a maximum :5 ! plate revolves at "r angles to ! l9e ( dip4 ,:5 ! revolution is 9 ! same direction ) t ( ! h&s ( a wat*1 ! curr5t ( electricity fl[s f its c5tre to ! circumf]5ce2 & :5 ! rotation is 9 a contr>y direction1 ! curr5t sets ! opposite way4 ,?us a copp] plate1 revolv+ at "r angles to ! l9e ( ! dip1 becomes a new electrical ma*9e1 diff]+ f ! common plate-glass ma*9e by ! copp] be+ ! mo/ p]fect conductor1 :]eas glass is ! mo/ p]fect non-conductor2 besides insulation1 :i* is ess5tial to ! glass ma*9e1 is fatal to ! copp] "o4 ,! quantity ( electricity evolv$ by ! metal does n appe> to be inf]ior to t devolv$ by ! glass1 ?\gh v diff]5t 9 int5sity4 ,ev5 a %ip cross+ ! l9es ( =ce mu/ h electric curr5ts runn+ ?r\gh h]4 ,dr4 ,f>aday obs]ves t su* is ! facility ) :i* electricity is g5]at$ by ! magnetic l9es ( =ce1 t sc>cely any piece ( metal c be mov$ )\t a developm5t ( x2 consequ5tly1 among ! arrangem5ts ( /eam-eng9es & metallic ma*9]y1 curi\s electro-magnetic comb9ations probably exi/ :i* h nev] yet be5 notic$4 ,?us magnetic l9es ( =ce c]ta9ly issue f ! surface ( ! globe4 ,no d\bt ! e>? is a magnet on a va/ scale1 b x diff]s f all o!rs 9 hav+ f\r poles ( maximum magnetic =ce ( diff]5t int5sities1 ! two 9 ! nor!rn hemisph]e hav+ a secul> motion 9 a contr>y direction f ! two 9 ! s\!rn4 ,!y are n ev5 symmetrically plac$2 h5ce ! magnetic int5sity v>ies s mu* 9 ! diff]5t po9ts on ! e>?'s surface1 t ! dynamic equator1 or l9e pass+ ?r\gh all ! po9ts ( lea/ int5sity1 is a v irregul> curve surr\nd+ ! globe1 b by no means co9cid+ ) ! t]re/rial equator4 ,9 consequ5ce ( ! mean action ( ^! f\r =ces1 ! nor? end ( a magnetis$ ne$le1 arrang$ s z to revolve 9 a v]tical plane1 dips or incl9es b5ea? ! horizon 9 ! nor!rn hemisph]e1 & ! s\? end 9 ! s\!rn4 ,! two hemisph]es are sep>at$ by a l9e encircl+ ! e>?1 call$ ! magnetic equator1 or l9e ( no dip1 9 :i* ! dipp+ or incl9ation ne$le is horizontal4 ,on ea* side ( ?is l9e ! incl9ation increases till at la/ ! ne$le becomes p]p5dicul> to ! horizon 9 two po9ts1 or r small spaces1 9 ea* hemisph]e1 kn[n z ! magnetic poles1 :i* are q diff]5t f ! poles ( ! e>?'s rotation4 ,! mean action ( ! f\r poles ( magnetic int5sity causes ! m>9]'s compass1 or a magnetic ne$le susp5d$ s z to revolve 9 a horizontal plane1 to rema9 at re/ :5 po9t+ to ! two magnetic poles4 ,x is !n 9 ! magnetic m]idian ( ! place ( obs]vation1 :i* is ?us det]m9$ by ! mean action ( all ! f\r magnetic =ces4 ,^! mean values ( ! ?ree magnetic elem5ts1 namely1 ! decl9ation1 incl9ation or dip1 & magnetic int5sity1 are well kn[n to be subject to secul>1 annual1 & diurnal v>iations4 ,! secul> only become s5sible aft] "s ye>s1 b ! annual & diurnal v>iations h a d\ble progression--t is to say1 two maximum & two m9imum values 9 _! respective p]iods ( a ye> & tw5ty-f\r h\rs2 = example1 ! decl9ation ne$le makes two deviations to ! we/ & two to ! ea/ 9 ! c\rse ( tw5ty-f\r h\rs1 & t ) great regul>ity4 ,n[ ,g5]al ,sab9e discov]$ t ! d\ble progression arises f two comb9$ or sup]pos$ v>iations hav+ diff]5t h\rs ( maxima & m9ima1 & t !y are due to two di/9ctly diff]5t causes--! "o be+ ! diff]5ce 9 ! sun's position relatively to ! place ( obs]vation at ! diff]5t seasons ( ! ye>1 & h\rs ( ! day & night2 ! o!r be+ a mean annual & diurnal v>iation prov$ by ,g5]al ,sab9e to exi/ 9 ^? great magnetic /orms or casual di/urbances :i* affect ! magnetic elem5ts simultane\sly ov] enorm\sly ext5sive tracts ( ! globe4 ,moreov] ! ,g5]al discov]$ t1 besides ^! annual & diurnal v>iations1 ! magnetic /orms h a v>iation :i* accompli%es its vicissitudes 9 t5 or m ne>ly elev5 ye>s1 ! increase f ye> to ye> be+ gradual1 till its maximum becomes twice z great z its m9imum value4 ,9 consequ5ce ( ?is inequality 9 ! /orms or casual di/urbances1 ea* ( ! magnetic elem5ts has a v>iation ( simil> p]iod & simil> maxima & m9ima4 ,n[ ! numb] & magnitude ( ! spots on ! sun _h be5 obs]v$ by ,m4 ,s*wabe1 ( ,dessau1 to increase to a maximum1 & decrease aga9 to a m9imum1 regul>ly 9 ! v same p]iod ( betwe5 t5 & elev5 ye>s2 & ,g5]al ,sab9e f\nd t ?is v>iation 9 ! sol> spots1 & t 9 ! magnetic elem5ts1 n only h ! same p]iods ( maxima & m9ima1 b t !y correspond 9 all _! m9ute/ vicissitudes4 ,?us a v rem>kable & unexpect$ connexion exi/s betwe5 t]re/rial & sol> magnetism4 ,! dual & antagoni/ pr9ciple is p]fectly ma9ta9$ 9 ! e>?'s magnetism1 all ! ph5om5a & _! v>iations be+ 9 opposite directions 9 ! two hemisph]es4 7,n4 #bbf47 ,no d\bt ! magnetic l9es ( =ce 9 ! e>? are clos$ curves1 z 9 artificial magnets2 b 9 _! circuit\s c\rses !y may ext5d to any di/ance 9 space1 or r 9 ! e!real m$ium1 ev5 to ?\s&s or t5s ( ?\s&s ( miles2 = ! e!real m$ium is p]meable to l9es ( magnetic =ce1 or r transmits !m1 o!rwise ! sol> spots c\ld n affect ! v>iations ( t]re/rial magnetism2 besides1 !y pass ?r\gh ! ,torricellian vacuum1 :i* is ne>ly a void ) respect to air1 b n to ! e!real m$ium4 ,! atmosph]e :i* surr\nds ! e>? to ! height ( ab\t fifty miles ) s5sible d5sity1 consi/s ( ?ree & a half p>ts by weight ( nitrog5 gas & "o "p ( oxyg51 uni=mly mix$4 ,! nitrog5 is neutral :e!r d5se or r>e1 hot or cold1 :ile ! oxyg5 is highly p>amagnetic2 b x loses a great "p ( its =ce :5 r>efi$ by heat2 consequ5tly ! magnetic =ce ( ! atmosph]e mu/ increase f ! equator to ! poles ( maximum cold2 x mu/ v>y summ] & w9t]1 night & day4 ,its effect ^u t]re/rial magnetism is unkn[n2 b x c h>dly be )\t "s influ5ce4 ,m4 ,e4 ,becqu]el obs]ves--8,if we reflect t ! e>? is encompass$ by a mass ( air equival5t 9 weight to a lay] ( m]cury ( #cj in*es1 we may inquire :e!r su* a mass ( magnetic gas1 cont9ually agitat$1 & submitt$ to ! regul> & irregul> v>iations ( pressure & temp]ature1 does n int]v5e 9 "s ( ! ph5om5a dep5d5t ^u t]re/rial magnetism4 ,if we calculate1 9 fact1 :at is ! magnetic =ce ( ?is fluid mass1 we f9d t x is equival5t to an imm5se plate ( iron1 ( a ?ickness little m ?an #a_/bej ( an in*1 :i* cov]s ! :ole surface ( ! globe40 ,bo? ! conduct+ p[] ( ! air & its d5sity are increas$ by cold2 & z ! sum ( ! magnetic =ces :i* issue f ! e>? on "o side ( ! l9e ( no dip is equal to _! sum on ! o!r side1 ! int5sity & conc5tration 9 our w9t] are co9cid5t ) a diffusion & feebl5ess 9 ! opposite hemisph]e1 s t ! l9e ( no dip w move annually f nor? to s\? & back aga94 ,! same holds ) reg>d to day & night4 ,?us ! law ( ! cons]vation ( =ce is rigor\sly ma9ta9$2 & x is equally s 9 ! effect ( ! atmosph]e on ! magnetic l9es ( =ce1 :i* refracts !m z !y pass ?r\gh x1 9 "o direction 9 summ]1 & 9 ! opposite direction 9 w9t]--9 "o direction 9 ! enlight5$ hemisph]e1 9 ! o!r 9 t :i* is d>k4 ,! :ole ( ! magnetic l9es ab\t ! e>? are held by _! mutual t5sion 9 "o connect$1 s5sitive sy/em1 :i* feels 9 e "p1 ev5 to ! antipodes1 a *ange 9 any p>ticul> place4 ,x may be m5tion$ z a well-kn[n fact1 t app>5t anomalies h be5 f\nd 9 ! diurnal v>iation ( ! decl9ation 9 ! high magnetic latitudes ( ! nor!rn hemisph]e :5 comp>$ ) _! great regul>ity 9 o!r p>ts ( ! same hemisph]e1 & t ! magnetic /orms are ( mu* great] magnitude !re ?an 9 l[] latitudes4 ,moreov]1 al?\gh ,capta9 ,maguire's obs]vations at ,cape ,b>r[1 9 ! ,nor? ,pol> ,ocean1 %[ t ! annual & diurnal v>iations ( ! casual di/urbances or magnetic /orms1 z well z ^? ( ! dec5nial p]iod1 are ma9ta9$1 yet x appe>s t at c]ta9 h\rs ( ! day ! di/urbance 9 ! decl9ation may be ea/]ly at ,po9t ,b>r[1 & we/]ly at ! ,magnetic ,obs]vatory at ,toronto1 9 ,upp] ,canada1 & vice v]s3 9 fact1 ! magnetic /orms are simultane\s at ^! two /ations1 b 9 opposite directions--a circum/ance n yet acc\nt$ =1 & may possibly be due to ! increas$ magnetism ( ! air 9 ^! cold regions4 ,! heat ( ! sun has no effect ^u t]re/rial magnetism unless possibly by its indirect action on ! oxyg5 ( ! atmosph]e2 b hi!rto x has be5 imp]ceptible4 ,x is h>dly possible t ! aurora c be indep5d5t ( ! magnetic "* ( ! air1 s9ce x occurs 9 ! high latitudes1 :]e ! atmosph]ic magnetism is mo/ p[]ful4 ,capta9 ,maguire rem>k$ t x frequ5tly appe>$ at ,po9t ,b>r[ :5 ! magnetic /orms 7 at a maximum4 ,we are totally ignorant ( ! cause ( t]re/rial magnetism1 ?\gh ! p[]ful influ5ce ( ! sol> spots r5d]s x highly probable t x w ultimately be f\nd to orig9ate 9 ! sun himself4 ,mr4 ,b>l['s !ory ( electric curr5ts revolv+ r\nd ! globe is borne out by ,mr4 ,fox's obs]vations 9 ! ,corni% m9es1 :i* %[ t electro-magnetism is extremely active 9 metallic ve9s2 t n only ! nature ( ! metallif]\s deposits mu/ h be5 det]m9$ by _! relative electrical conditions1 b t ! direction ( ! metallic ve9s mu/ h be5 influ5c$ by ! direction ( ! magnetic m]idians1 & 9 fact almo/ all ! metallic deposits 9 ! _w t5d f ea/ to we/1 or f nor?-ea/ to s\?-we/4 ,h[ev]1 ^! curr5ts ( electricity may be reg>d$ z magnetic l9es ( =ce1 & are m likely to be ! effect ?an ! cause ( t]re/rial magnetism4 ,!y are f\nd to h a p[]ful inductive effect on ! ,atlantic telegraph1 di/urb+ ! ne$les & galvanomet]s at ea* end ( ! l9e to a consid]able degree1 & on ! night ( ! #f? ( ,septemb]1 #aheh1 a magnetic /orm pass$ ov] ! cable1 :i* viol5tly agitat$ ! reflect+ galvanomet] 9 connection ) ! telegraphic wires4 ,we are equally ignorant ( ! cause ( ! secul> magnetic v>iations1 b we h no reason to believe t ! e>? is alone magnetic2 on ! contr>y1 ! planets are probably magnets1 & we "k t ! sun & moon are magnetic2 h5ce1 z ! magnetic1 l ! gravitat+ =ce1 is transmitt$ ?r\gh ! e!real m$ium1 ! induction ( ! sun1 moon1 & planets1 9 all _! secul> & p]iodic *anges1 may cause p]petual v>iations 9 t]re/rial magnetism1 & x may n be beyond ! delicacy ( mod]n obs]vation to asc]ta9 :e!r a planet1 :5 ne>e/ to ! e>?1 has any s5sible magnetism4 ,diamagnetism is also a dual p[]1 b 9 complete anti!sis to p>amagnetism "u ! same circum/ances4 ,dr4 ,f>aday fir/ discov]$ ?is prop]ty 9 heavy glass1 or silico-borate ( lead1 a piece ( :i* 0 repell$ by ! pole ( a p[]ful electro-magnet1 & an elongat$ prism ( ! same heavy glass1 :5 freely susp5d$ betwe5 ! poles1 set equatorially4 ,he !n f\nd t s great a numb] ( sub/ances foll[$ ! same law1 t x e/abli%$ ! v rem>kable fact ( a hi!rto unkn[n =ce hav+ act$ ^u ! sub/ances submitt$ to its influ5ce1 a discov]y :i* he subsequ5tly confirm$ by _m exp]im5ts1 all ( :i* prov$ ! anti!sis betwe5 ! two modes ( magnetic action4 ,he also discov]$ t magnetic bodies diff] exce$+ly 9 _! magnetic p[]3 ( p>amagnetic bodies iron is ! mo/ p[]ful2 !n foll[ nickel1 cobalt1 & a long gradation d[n to osmium & a vacuum4 ,! body t seems to h ! l[e/ diamagnetic p[] is ars5ic1 & ! s]ies asc5ds to heavy glass1 antimony1 phosphorus1 & bismu?2 s iron & bismu? are ! mo/ p[]ful 9 _! respective classes1 & bo? h a small conduct+ p[] = electricity4 ,x may be presum$ t _m rem>kable in/ances ( diamagnetism are to be met ) 9 nature2 among o!rs1 ,dr4 ,f>aday has sugge/$ ! idea t ,saturn's r+1 f its position1 may be diamagnetic ) reg>d to ! planet4 ,) v p[]ful magnets or electro-magnets1 :i* are absolutely necess>y = all ^! exp]im5ts1 x is f\nd t no simple sub/ance is neutral1 b t su* may be comp\nd$ by mix+ 9 due proportion a diamagnetic & p>amagnetic liquid1 z wat] & protosulphate ( iron4 ,pr(essor ,tyndall prov$ diamagnetic pol>ity by plac+ two bismu? b>s )9 two v]tical coils or spirals ( insulat$ copp] wire1 ?r\gh :i* electric curr5ts 7 transmitt$ f a galvanic batt]y1 & caus$ to act ^u a /eel magnet freely susp5d$ )\t ! spirals4 ,n[1 :5 ! excit$ magnetism is m]ely by induction1 ! electric curr5t1 be+ mom5t>y1 only causes a %ock or mom5t>y deviation 9 ! magnet1 :i* returns to its orig9al position :5 ! curr5t ceases4 ,:51 on ! contr>y1 ! magnetism is p]man5t1 ! susp5d$ magnet does n return to its orig9al position :5 ! curr5t ceases4 ,9 ,pr(essor ,tyndall's exp]im5t ! deviation 0 p]man5t1 & x 0 equally s :5 a bismu? b> 0 freely susp5d$ & ! cores )9 ! spirals 7 /eel magnets4 ,_h ! effect be5 f curr5ts induc$ 9 ! mass ( ! b> ( bismu?1 division ( ! b> w\ld h /opp$ !m1 b ! result 0 ! same ) p[d]$ bismu? z ) ! solid mass4 ,moreov]1 s9ce ! /r5g? ( induc$ curr5ts dep5ds ^u ! conduct+ p[] ( ! sub/ance1 & z ! conduct+ p[] ( copp] is =ty times z great z t ( bismu?1 _h ! pol>ity be5 induc$ & n real1 ! effect ought to h be5 =ty times great] :5 copp] in/ead ( bismu? cores 7 put 9 ! spirals1 :]eas x 0 sc>cely s5sible4 ,besides ^! pro(s1 ,dr4 ,tyndall made exp]im5ts ) elev5 diff]5t diamagnetic sub/ances1 ( :i* wat] 0 "o1 ) simil> results4 ,he !n det]m9$ ! pol>ity ( twelve p>amagnetic bodies by ! same me?od1 :5ce x appe>$ t ! same action :i* produc$ a nor? pole 9 ! p>amagnetic bodies produc$ a s\? pole 9 ^? t 7 diamagnetic1 & vice v]s1 :5ce he concludes t diamagnetic pol>ity is "o ( ! mo/ firmly e/abli%$ tru?s ( sci5ce4 ,x foll[s f ?is t1 :5 a man is /&+1 8 head is a nor? pole & 8 feet a s\?1 & ! top ( an iron rail+ on :i* he may be lean+ is a s\? pole & ! l[] end a nor?4 ,diamagnetic bodies ?us possess a pol>ity1 ! same 9 k9d b opposite 9 direction to t possess$ by p>amagnetic ones4#ah ,!y are bo? dual p[]s1 & ! two diamagnetic =ces l ! two p>amagnetic be+ coexi/5t1 simultane\s1 & mutually dep5d5t1 !re c be no d\bt t ! diamagnetic =ces also are repres5t$1 or r consi/ ( curv$ & clos$ l9es ( =ce pass+ ?r\gh ! int]ior ( ! sub/ance4 ,dr4 ,tyndall has prov$ t ! attraction ( iron1 & ! repulsion ( bismu?1 are z ! squ>e ( ! electro-magnetic curr5t produc+ !m1 & t diamagnetic sub/ances are capable ( induction4 ,! molecul> /ructure ( sub/ances freely susp5d$ betwe5 ! poles ( a magnet has a decid$ effect ^u ! position !y assume4 ,x has already be5 m5tion$ t ! optic axis is a symmetrical l9e 9 a d\bly refract+ cry/al 9 :i* !re is no d\ble refraction1 & t 9 "s cry/als !re are two su* symmetrical l9es4 ,n[1 ,pr(essor ,plck] ( ,bonn discov]$1 :5 su* cry/als are submitt$ to p[]ful magnetic influ5ce1 t ! s+le optic axis 9 ! "o1 & ! resultant or mean l9e betwe5 ! d\ble optic axes 9 ! o!r1 set diametrically or at "r angles to ! l9e ( magnetic =ce2 & s p[]ful did ! ,pr(essor f9d ! action ( magnetism on cry/all9e =m1 t ! m9]al cyanite1 :5 susp5d$1 arranges itself s def9itely ) reg>d to t]re/rial magnetism1 t x might be us$ z a compass ne$le4 ,dr4 ,f>aday aft]w>ds obs]v$ t amorph\s sub/ances1 cut 9 ! =m ( a sph]e1 h no t5d5cy to set or be attract$ or repell$ 9 "o direction 9 pref]5ce to any o!r2 b if ! sph]e be =m$ ( a cry/alliz$ sub/ance1 x is a g5]al fact t1 :e!r x be p>amagnetic or diamagnetic1 x is m p[]fully attract$ or repell$ 9 "o direction ?an 9 any o!r--a prop]ty nam$ by ,dr4 ,f>aday magnecry/allic action4 ,= example1 a sph]e ( calc>e\s sp>1 :i* is a diamagnetic cry/al1 is mo/ /rongly repell$ 9 ! direction ( its pr9cipal optic axis1 & lea/ /rongly 9 ! direction ( its lea/ axis4 ,9 a sph]e ( c>bonate ( iron1 :i* has exactly ! same cry/all9e =m & is highly p>amagnetic1 ! l9e :i* 9 c>bonate ( lime sets equatorially1 9 ?is case sets axially1 & m /rongly 9 t direction ?an 9 any o!r4 ,! law accord+ to :i* ! attraction ( ! c>bonate ( iron increases f ! lea/ to its greate/ or pr9cipal optic axis1 is precisely ! same z t accord+ to :i* ! repulsion ( ! calc>e\s sp> increases f ! lea/ to ! pr9cipal optic axis4 ,^! relations are n alt]$ by ! imm]sion ( ! sph]es 9 liquids ( ei!r magnetism4 ,dr4 ,f>aday obs]v$ t a l9e at "r angles to ! planes ( pr9cipal cleavage 9 cry/als takes ! axial position1 & on t acc\nt he call$ x ! magnecry/allic axis4 ,its position 0 prov$ by ,,mm4 ,tyndall & ,knoblau* to dep5d ^u ! g5]al fact1 t ! mass is mo/ /rongly repell$ 9 ! direction ( ! planes ( pr9cipal cleavage1 & t ! elective position ( cry/als dep5ds m ^u ! direction ( ^! planes ) respect to ! electric =ce1 ?an ^u ! optic axis4 ,! planes ( pr9cipal cleavage set !mselves equatorially 9 diamagnetic1 & axially 9 p>amagnetic sub/ances3 x 0 !nce inf]r$ t ! ph5om5a (f]$ by cry/als 9 ! magnetic field is a p>ticul> case ( ! g5]al law1 t ! sup]ior action ( magnets ^u matt] 9 a p>ticul> direction is due to ! p>ticles ( ! body be+ clos] toge!r 9 t direction ?an 9 any o!r3 9 %ort1 ! l9e ( maximum d5sity2 ! =ce ex]t$ be+ attractive or repulsive accord+ z ! p>ticles are p>amagnetic or diamagnetic4 ,x appe>s1 h[ev]1 t ! set ( cry/als ) reg>d to ! l9e ( magnetic =ce does n dep5d solely ^u _! d5sity 9 p>ticul> directions4 ,pr(essor ,matteucci1 ( ,pisa1 has prov$ t ! diamagnetic =ce is inv]sely z ! conduct+ p[] ( sub/ances = electricity1 t ! conduct+ p[] is a maximum 9 ! planes ( pr9cipal cleavage1 & t a ne$le ( cry/alliz$ bismu?1 9 :i* ! planes ( cleavage are p>allel to its l5g?1 places itself equatorially ) m =ce :5 ^! planes are v]tical1 or at "r angles to ! =ce1 ?an :5 !y are horizontal or p>allel to x4 ,exp]im5ts _h hi!rto be5 made only ) diamagnetic or slightly p>amagnetic bodies1 :i* induc$ ,m4 le ,r\x to try ! effect ( magnetism on pulv]iz$ iron compress$ by ! hydraulic press1 :i* r$uc$ ! gra9s ( iron to lamell equival5t to planes ( cleavage4 ,cubes ( ?is sub/ance1 susp5d$ by a ?read ov] a horse%oe magnet1 oscillat$ = a long] "t :5 ! lamell 7 p]p5dicul> ?an :5 !y 7 horizontal2 t is1 ! =ce 0 /rong] :5 ! lamell 7 equatorial ?an :5 !y 7 axial1 exactly ! same result z 9 ,pr(essor ,matteucci's exp]im5t ) ! ne$le ( bismu?4 ,?us ! v]tical position ( ! cleavages1 :i* increases ! diamagnetism ( ! bismu?1 increases also ! p>amagnetism ( ! iron4 ,m4 le ,r\x obs]ves t ^! results are indep5d5t ( ! influ5ce ( ! curr5ts ( electricity induc$ 9 ! oscillat+ body1 = ! fundam5tal "* ( ! ph5om5a ( ,arago's discov]y ( rotation by induction is1 t ! oscillations dim9i% rapidly 9 ext5t )\t any s5sible dim9ution 9 _! duration1 :ile 9 8 exp]im5ts ! "t ( ! oscillations v>i$4 ,he concludes t ! arrangem5t ( ! molecules mu/ be intimately connect$ ) p>amagnetism or diamagnetism itself1 s9ce ! effect ( t arrangem5t is equally s5sible 9 bismu? & iron1 al?\gh ! diamagnetism ( ! =m] is #be1jjj times weak] ?an ! p>amagnetism ( ! latt]4 ,! diamagnetism ( conduct+ sub/ances & metals1 su* z gold1 silv]1 & copp]1 is augm5t$ by division4 ,compression has also a great effect on magnetic action4 ,= example1 a b> ( s(t iron sets ) its longe/ dim5sions f pole to pole ( a magnet1 b a b> ( compress$ c>bonate ( iron-du/1 ^: %orte/ dim5sions co9cide ) ! l9e ( pressure1 sets equatorially4 ,a b> ( bismu? ^: plane ( pr9cipal cleavage is p>allel to its l5g? sets equatorially1 b a b> ( compress$ bismu? du/1 ^: %orte/ dim5sions co9cide ) ! l9e ( pressure1 or a b> ( bismu? ^: pr9cipal planes ( cleavage are transv]se to its l5g?1 sets ) its l5g? axially4 ,! anti!sis is p]fect :e!r ! b>s are "u ! influ5ce ( a magnet or electro-magnet4 ,= s9ce ! diamagnetic =ce is inv]sely z ! conduct+ p[] ( a body = electricity1 & t ! latt] is a maximum 9 ! direction ( ! planes ( pr9cipal cleavage1 !re=e :5 ^! planes are p>allel to ! axis ( ! bismu? b> x sets equatorially2 b z ! conduct+ p[] is augm5t$ :5 ! bismu? du/ is compress$ 9 ! direction ( ! =ce1 ! diamagnetic p[] is dim9i%$1 & ! b> sets axially4 ,aga91 s9ce ! p>amagnetic =ce augm5ts ) ! conduct+ p[]1 ! action ( ! magnet on ! iron is anti!tic to t on ! bismu?4 ,! action ( an electro-magnet on copp] is /rongly contra/$ ) t :i* x ex]ts on iron or bismu?4 ,= :5 a copp] b> susp5d$ by a ?read revolves be=e its pole1 x is br\ght to a dead halt z soon z ! electric curr5t acts ^u x1 & ma9ta9s its position ) consid]able t5acity1 = x does n return :5 pu%$ out ( x1 b keeps its new place ) /iffness2 h[ev]1 z soon z ! electric curr5t ceases1 !re is a /rong revulsion1 ! b> revolv+ ! contr>y way4 ,ev5 :5 sw++ ) consid]able =ce x may be caught & reta9$ 9 any position at pleasure1 b !re is no revulsion :5 x is arre/$ ei!r 9 ! axial or equatorial position2 at any angle betwe5 ^! two1 b especially midway1 ! electricity w make x move t[>ds ! axis1 b x is arre/$ be=e x comes to x4 ,! action dep5ds mu* on ! =m & dim5sions ( ! b> & ! magnetic pole1 :i* ought to be flat4 ,! ph5om5a are due to ! high electro-conduct+ p[] ( ! copp]1 & are met ) 9 "s ( ! o!r pure metals1 ?\gh 9 a f> inf]ior degree4 ,great magnetic p[] is requisite = all ^! exp]im5ts4 ,dr4 ,f>aday employ$ a magnet t c\ld su/a9 a weight ( #dej lbs4 at ea* pole1 & ! poles 7 ei!r po9t$ or flat surfaces at pleasure1 z ! k9d ( exp]im5t requir$4 ,heat /rongly affects ! magnetic prop]ties ( bodies4 ,dr4 ,f>aday f\nd t1 :5 ! temp]ature ( nickel is increas$1 its magnetic =ce dim9i%es2 :5 t ( iron is increas$ its magnetic =ce rema9s ! same1 :ile t ( cobalt increases2 :i* seems to indicate t !re is a temp]ature at :i* ! magnetic =ce is a maximum1 above & bel[ :i* x dim9i%es4 ,nickel loses its magnetism at ! temp]ature ( boil+ oil1 iron at a r$ heat1 & cobalt ne> ! temp]ature at :i* copp] melts4 ,calc>e\s sp> reta9s its magnetic "* at a v high temp]ature2 b ! same sub/ance :5 x conta9s iron1 & also oxide ( iron1 loses x entirely at a dull r$ heat4 ,a cry/al ( ! f]roc>bonate ( lime 0 absolutely rev]s$ by *ange ( temp]ature1 = at a l[ heat ! optic axis po9t$ axially1 & at a high temp]ature equatorially4 ,) ! exception ( ^! sub/ances1 magnecry/als1 :e!r p>amagnetic or diamagnetic1 are g5]ally all affect$ alike by heat4 ,! diff]5ce betwe5 ! =ces 9 any two diff]5t directions1 z = in/ance ! greate/ & lea/ pr9cipal axes1 dim9i%es z ! temp]ature is rais$1 increases z ! temp]ature is l[]$1 & is con/ant = a giv5 temp]ature4 ,no unmix$ or pure sub/ance has z yet pass$ by heat f ! p>amagnetic to ! diamagnetic /ate4 ,no simple magnecry/al has %[n any inv]sion ( ?is k9d1 nor h any ( ! *ief axes ( p[] *ang$ _! *>act]s or relations to "o ano!r4 ,x appe>s t1 z ! molecules ( cry/als & compress$ bodies affect magnetism1 s magnetism acts ^u ! molecules ( matt]1 = torsion dim9i%es ! magnetic =ce1 & ! ela/icity ( iron & /eel is alt]$ by magnetism4 ,m4 ,matteucci has f\nd t ! me*anical compression ( glass alt]s ! rotatory p[] ( a pol>iz$ ray ( light transmitt$ ?r\gh x1 & t a *ange takes place 9 ! temp] ( glass "u ! influ5ce ( p[]ful magnetism4 ,ev5 f ! limit$ view ( ! p[]s ( nature :i* prec$es1 x is evid5t t ! progress ( sci5ce bas$ ^u exp]im5t t5ds to %[ t ! v>i\s =ces ( light1 heat1 motion1 *emical aff9ity1 electricity1 & magnetism w ultimately be trac$ to "o common orig92 t !y are s directly relat$1 & mutually dep5d5t1 t !y are conv]tible1 motion produc+ heat1 & heat motion2 *emical aff9ity produc+ electricity1 & electricity *emical action1 c41 ea* m$iately or imm$iately produc+ ! o!r4 ,^! =ces are transmitt$ ?r\gh sub/ances2 !y act ^u matt]1 caus+ *anges 9 ! molecul> /ructure ( bodies ei!r mom5t>y or p]man5t1 & reciprocally ! *anges indicate ! action ( ^! =ces4 ,matt] & =ce are only kn[n to u z manife/ations ( ,almighty p[]3 we are assur$ t we c nei!r create nor de/roy !m--t _! am\nt is ! same n[ z 9 ! beg9n+4 ,9 *emical attraction ! p[]s ) :i* a molecule ( matt] is end[$1 & :i* give rise to v>i\s qualities1 nev] *ange2 ev5 :5 pass+ ?r\gh a ?\s& comb9ations1 ! molecule & its p[] are ev] ! same4 ,ma*9]y does n create =ce2 x only enables u to turn ! =ces ( nature to ! be/ advantage2 x is by ! =ce ( w9d or fall+ wat] t our corn is gr\nd1 & ! /eam eng9e owes its p[] to ! =ce ( heat & *emical action4 ,z =ce _c be creat$1 nei!r c x be annihilat$4 ,x may be disp]s$ 9 v>i\s directions1 & subdivid$ s z to become evanesc5t to our p]ceptions2 x may be balanc$ s z to be 9 abeyance1 or become pot5tial z 9 /atic electricity2 b ! in/ant ! imp$im5t is remov$ ! =ce is manife/$ by motion2 x may also be turn$ into heat by friction1 b x is nev] lo/4 ,e motion we make1 e brea?1 e ^w we utt]1 is a =ce t produces pulsations :i* are communicat$ to cont9ually increas+ p>ticles ( air1 & convey$ ?r\gh c\ntless *annels s z to become inde$ imp]ceptible to our s5ses1 yet !y are demon/rat$ to exi/ z witnesses ( ! words we h spok5 or ! actions we h p]=m$1 by analysis1 t all-p[]ful in/rum5t ( human reason4#ai ,a body acquires heat 9 ! exact proportion t ! adjac5t sub/ances become cold1 & :5 heat is absorb$ by a body x becomes an expansive =ce at ! exp5se ( ^? ar\nd t contract1 b x is n lo/4 ,9 *emical action at a di/ance ! pr9ciple ( ! cons]vation ( =ce is ma9ta9$1 = a *emical action may be produc$ miles away f an electro-magnet1 p]fectly equival5t to ! dom9ant *emical action 9 ! batt]y4 ,! two electricities are develop$ 9 equal proportions1 :i* may be comb9$ s z to produce _m *anges 9 _! respective relations1 yet ! sum ( ! =ce ( "o k9d c nev] be made 9 ! smalle/ degree ei!r to exce$ or to come %ort ( ! sum ( ! o!r4 ,exp]im5tal rese>* proves t ! cons]vation ( =ce is an unalt]able law ( nature--8a pr9ciple 9 physics z l>ge & sure z t ( ! inde/ructibility ( matt] or ! inv>iability ( gravity4 ,no hypo!sis %\ld be admitt$1 nor any ass]tion ( a fact cr$it$1 t d5ies ?is pr9ciple4 ,no view %\ld be inconsi/5t or incompatible ) x4 ,_m ( our hypo!ses 9 ! pres5t /ate ( sci5ce may n compreh5d x1 & may be unable to sugge/ its consequ5ces1 b none %\ld oppose or contradict x40 ,hav+ ?us express$ 8 conviction ( ! tru? ( ?is great pr9ciple1 ,dr4 ,f>aday consid]s ! case ( gravity1 & concludes t 8! def9ition ( gravity z an attractive =ce betwe5 ! p>ticles ( matt] v>y+ inv]sely z ! squ>e ( ! di/ance1 :ile x /&s z a full def9ition ( ! p[]1 is inconsi/5t ) ! pr9ciple ( ! cons]vation ( =ce40 ,= :ile 9 ?is def9ition ! pr9ciple is ma9ta9$ ( ! con/ancy ( ! =ce at ! same di/ance1 x implies a creation ( =ce to an enorm\s am\nt :5 ! di/ance is dim9i%$1 & an equal am\nt annihilat$ :5 ! di/ance is increas$1--8an effect10 he says1 8:i* is equal 9 its inf9ity & its consequ5ces ) creation1 & only )9 ! p[] ( ,him :o creates40 ,he cont9ues1 8,x w n be imag9$ = a mom5t t ,i am oppos$ to :at may be call$ ! law ( gravitat+ action1 t is1 ! law by :i* all ! kn[n effects ( gravity are gov]n$2 :at ,i am consid]+ is ! def9ition ( ! =ce ( gravitation4 ,t ! result ( "o ex]cise ( a p[] may be inv]sely z ! squ>e ( ! di/ance1 ,i believe & admit2 & ,i "k t x is s 9 ! case ( gravity1 & has be5 v]ifi$ to an ext5t t c\ld h>dly h be5 )9 ! conception ( ,newton himself :5 he gave utt]ance to ! law2 b t ! totality ( a =ce c be employ$ accord+ to t law ,i d n believe ei!r 9 relation to gravitation1 or electricity1 or magnetism1 or any o!r suppos$ =m ( p[]4 ,t !re %\ld be a p[] ( gravitation exi/+ by itself1 hav+ no relation to ! o!r natural p[]s1 & no respect to ! law ( ! cons]vation ( =ce1 is z little likely z t !re %\ld be a pr9ciple ( levity z well z gravity4 ,gravity may be only ! residual "p ( ! o!r =ces ( nature1 z ,mossotti has tri$ to %[2 b t x %\ld fall out f ! law ( all o!r =ces1 & %\ld be outside ! rea* ei!r ( f>!r exp]im5t or philosophical conclusions1 is n probable4 ,s we mu/ /rive to le>n m ( ?is out/&+ p[]1 & endeav\r to avoid any def9ition ( x :i* is incompatible ) ! pr9ciples ( =ce g5]ally1 = all ! ph5om5a ( nature lead u to believe t ! great & gov]n+ law is "o4 ,?us gravitation c only be consid]$ z "p ( a m g5]al =ce ^: law has yet to be discov]$40 ,! def9ition ( ! gravitat+ =ce imm$iately sugge/s ! "q ( h[ x is transmitt$2 ! full =ce ( t "q 0 felt by ,newton himself :51 9 8 ?ird lett] to ,b5tley1 he wrote1 8,t gravity %\ld be innate1 inh]5t1 & ess5tial to matt]1 s t "o body may act ^u ano!r at a di/ance1 ?r\gh a vacuum1 )\t ! m$iation ( any?+ else by & ?r\gh :i* _! action & =ce may be convey$ f "o to ano!r1 is to me s great an absurdity t ,i believe no man :o has 9 philosophic matt]s a compet5t faculty ( ?9k+ c ev] fall into x4 ,gravity mu/ be caus$ by an ag5t1 act+ con/antly accord+ to c]ta9 laws2 b :e!r ?is ag5t be mat]ial or immat]ial ,i h left to ! consid]ation ( my read]s40 ,s9ce ,newton's "t ! cont9ual decrease 9 ! p]iodic times ( ! comets belong+ to our sy/em1 & ! undulatory !ory ( light & heat1 h prov$ ! exi/5ce ( an extremely r>e ela/ic m$ium fill+ space ev5 to ! mo/ di/ant regions ( :i* we are cognizant4 ,b1 r>e z x may be1 x has in]tia en\gh to resi/ ! motion ( comets1 & !re=e mu/ be mat]ial1 :e!r consid]$ to be e!r or1 accord+ to ,mr4 ,grove1 ! highly att5uat$ atmosph]es ( ! cele/ial bodies4 ,pr(essor ,william ,?omson ( ,glasg[ has comput$ t 9 ! space trav]s$ by ! e>? 9 its annual revolution1 a cube ^: side is #ajjj miles w\ld conta9 n less ?an a p\nd weight ( ! e!real m$ium1 & t ! e>?1 9 mov+ ?r\gh x1 w\ld n displace ! #bej? "p ( t p\nd ( matt]4 ,yet t is enorm\sly m d5se ?an ! cont9uation ( ! e>?'s atmosph]e w\ld be 9 int]planet>y space1 if r>efi$ accord+ to ,bayle's law4 ,b :atev] be ! d5sity or nature ( ! e!r1 !re is e reason to believe t x is ! m$ium :i* transmits ! gravitat+ =ce f "o cele/ial object to ano!r1 or possibly x may possess a high] attribute ) reg>d to gravity ?an its m]e transmission4 ,dr4 ,f>aday1 :o discov]$ ! magnetism ( ! atmosph]e1 is l$ to believe t ! e!real m$ium too is magnetic by ! foll[+ exp]im5t4 ,?ree solutions ( ! protosulphate ( iron1 l1 m1 n1 ! fir/ ( :i* conta9$ #d gra9s ( ! salt dissolv$ 9 a cubic in* ( wat]1 ! second #h gra9s1 & ! ?ird #af gra9s--^! 7 respectively enclos$ 9 ?ree glass globules1 all ( :i* 7 attract$ by ! pole ( a magnet4 ,a quantity ( ! mean solution m 0 !n put into a vessel1 & ! globule conta9+ ! /ronge/ solution n 0 imm]s$ 9 x1 :i* 0 attract$ z be=e1 b ! globule l1 conta9+ ! weake/ solution1 0 repell$ :5 plung$ into ! same liquid4 ,"h !re 0 a diamagnetic ph5om5on1 al?\gh ! glass globules & ! liquid 9 :i* !y 7 imm]s$ conta9$ iron4 ,! effect 0 evid5tly diff]5tial1 = :5 ! liquid 0 less attract$ ?an ! globule1 ! globule approa*$ ! pole1 & :5 ! liquid 0 m attract$ ?an ! globule1 ! latt] appe>$ to rec$e f ! pole4 ,9 fact1 ! effect is ! same z t ( gravity on a body imm]s$ 9 wat]2 if x be m =cibly attract$ ?an ! wat]1 x s9ks2 if less =cibly attract$1 x rises1 ! effect be+ ! same z if x 7 repell$ by ! e>?4 ,h5ce ! "q1 are all magnetic ph5om5a ! result ( a diff]5tial action ( ?is k9d1 & is ! e!real m$ium less /rongly attract$ ?an s(t iron1 & m /rongly attract$ ?an bismu?1 ?us p]mitt+ ! approa* ( ! iron1 b caus+ ! bismu? to rec$e f ! pole ( a magnet8 ,if su* a m$ium exi/1 t is1 if ! e!real m$ium be magnetic1 !n diamagnetism is ! same ) p>amagnetism1 & ! pol>ity ( ! magnetic =ce 9 iron & bismu? is "o & ! same4 ,! e!real m$ium may be presum$ to transmit ! gravitat+ =ce2 x transmits ! magnetism ( ! sol> spots1 its undulations con/itute light1 heat1 & all ! influ5ces b\nd up 9 ! sol> beam2 & ! mo/ p]fect vacuum we c make is capable ( transmitt+ me*anical en]gy 9 enorm\s quantities1 "s ( :i* diff] b little f t ( air or oxyg5 at an ord9>y b>ometric pressure2 & :y n ?us admit1 says ,mr4 ,?omson1 ! magnetic prop]ty1 ( :i* we "k s little t we h no "r to pron\nce a negative8 ,mr4 ,wat]/one is also ( op9ion t x w\ld be tak+ too n>r[ a view if we limit$ ! function ( ! lum9if]\s e!r to ! convey+ ( physical pulses only4 ,! atmosph]e also conveys physical pulses1 b t is ! lea/ important ( its functions 9 ! economy ( nature4 ,!re is no?+ t %\ld h9d] u attribut+ to ! m$ia conc]n$ 9 ! radiation ( light & heat ! high] functions ( electrical pol>ity & gravitation4 ,! special dynamic arrangem5ts by :i* ?is is effect$ may ev] elude our rese>*2 b z !re is no limit to ! vis viva 7,n4 #bbb7 :i* su* m$ia may cons]ve 9 _! m9ute/ p>ts1 s !re is no physical impossibility 9 t vis viva be+ sudd5ly transf]r$ to ! molecules ( ord9>y matt] 9 ! proportion & sequ5ce requir$ to c>ry out ! ord] & sy/em ( nature4 ,! fundam5tal pr9ciple ( action 9 su* m$ia mu/ be 9 accordance ) ela/ic impact1 = ^u t ! dynamic !ory ( heat & cons]vation ( =ce re/s z a f\ndation4 ,! /atical & dynamical *>act]i/ics ( gravitation & transfusion ( =ce con=m to x1 s t all ! =ces t hold ! molecules ( bodies toge!r mu/ also be 9 subjection to x4#bj ,,section ,,xxxv4 ,e!real ,m$ium--,comets--,d n di/urb ! ,sol> ,sy/em--,_! ,orbits & ,di/urbances--,m4 ,faye's ,comet probably ! same ) ,lexel's--,p]iods ( o!r ?ree kn[n--,accel]ation 9 ! mean ,motions ( ,encke's & ,biela's ,comets--,! ,%ock ( a ,comet--,di/urb+ ,action ( ! ,e>? & ,planets on ,encke's & ,biela's ,comets--,velocity ( ,comets--,! ,comet ( #abfd--,! great ,comet ( #acdc--,physical ,con/itution--,%9e by borr[$ ,light--,e/imation ( _! ,numb]4 ,,9 consid]+ ! con/itution ( ! e>?1 & ! fluids :i* surr\nd x1 v>i\s subjects h pres5t$ !mselves to our notice1 ( :i* "s1 = aught we "k1 are conf9$ to ! planet we inhabit2 "s are common to x & to ! o!r bodies ( our sy/em4 ,b an all-p]vad+ e!r mu/ fill ! :ole visible creation1 s9ce x conveys1 9 ! =m ( light1 tremors :i* may h be5 excit$ 9 ! deepe/ recesses ( ! univ]se ?\s&s ( ye>s be=e we 7 call$ into be+4 ,! exi/5ce ( su* a m$ium1 ?\gh at fir/ hypo!tical1 is prov$ by ! undulatory !ory ( light1 & r5d]$ c]ta9 by ! motion ( comets1 & by its action ^u ! vap\rs ( :i* !y are *iefly compos$4 ,x has (t5 be5 imag9$ t ! tails ( comets h infus$ new sub/ances into our atmosph]e4 ,possibly ! e>? may attract "s ( t nebul\s matt]1 s9ce ! vap\rs rais$ by ! sun's heat1 :5 ! comets are 9 p]ihelio1 & :i* =m _! tails1 are scatt]$ ?r\gh space 9 _! passage to _! aphelion2 b x has hi!rto produc$ no effect1 nor h ! seasons ev] be5 influ5c$ by ^! bodies4 ,! light ( ! comet ( ! ye> #ahaa1 :i* 0 s brilliant1 did n imp>t any heat ev5 :5 cond5s$ on ! bulb ( a !rmomet] ( a /ructure s delicate t x w\ld h made ! hundr$? "p ( a degree evid5t4 ,9 all probability1 ! tails ( comets may h pass$ ov] ! e>? )\t its inhabitants be+ consci\s ( _! pres5ce2 & !re is reason to believe t ! tail ( ! great comet ( #ahdc did s4 ,m4 ,valz obs]v$ t ! light ( a brilliant comet 0 eclips$ z x pass$ ov] a /> ( ! #g? magnitude1 :5ce ,m4 ,bab9et comput$ t ! light ( ! comet mu/ h be5 sixty times less ?an t ( ! />1 & t matt] s att5uat$ c\ld n p5etrate ! e>?'s atmosph]e1 b ! con/itution ( ^! bodies is /ill a matt] ( conjecture4 ,! passage ( comets has nev] s5sibly di/urb$ ! /ability ( ! sol> sy/em2 _! nucleus1 be+ 9 g5]al only a mass ( vap\r1 is s r>e1 & _! transit s rapid1 ev5 :5 !y _h a solid "p1 t ! "t has n be5 long en\gh to admit ( a suffici5t accumulation ( impetus to produce a p]ceptible action4 ,inde$1 ,m4 ,dusej\r has %[n t1 "u ! mo/ fav\rable circum/ances1 a comet _c rema9 long] ?an two h\rs & a half at a less di/ance f ! e>? ?an #aj1ejj leagues4 ,! comet ( #aggj pass$ )9 ab\t six times ! di/ance ( ! moon f ! e>?1 )\t ev5 affect+ our tides4 ,accord+ to ,la ,place1 ! action ( ! e>? on ! comet ( #aggj augm5t$ ! p]iod ( its revolution by m ?an two days2 &1 if comets _h any p]ceptible di/urb+ en]gy1 ! reaction ( ! comet ought to h increas$ ! l5g? ( our ye>4 ,_h ! mass ( t comet be5 equal to ! mass ( ! e>?1 its di/urb+ action w\ld h increas$ ! l5g? ( ! sid]eal ye> by #b;h #ecm2 b1 z ,delambre's computations f ! ,gre5wi* obs]vations ( ! sun %[ t ! l5g? ( ! ye> has n be5 increas$ by ! fraction ( a second1 its mass c\ld n h be5 equal to ! #a_/ejjj? "p ( t ( ! e>?4 ,?is acc\nts = ! same comet hav+ twice swept ?r\gh ! sy/em ( ,jupit]'s satellites )\t d]ang+ ! motion ( ^! moons4 ,m4 ,dusej\r has comput$ t a comet1 equal 9 mass to ! e>?1 pass+ at ! di/ance ( #ab1aej leagues f our planet1 w\ld increase ! l5g? ( ! ye> to #cfg;d #af;h #em1 & ! obliquity ( ! ecliptic z mu* z #b4 ,s ! pr9cipal action ( comets w\ld be to alt] ! cal5d>1 ev5 if !y 7 d5se en\gh to affect ! e>?4 ,comets trav]se all p>ts ( ! heav5s2 _! pa?s h e possible incl9ation to ! plane ( ! ecliptic1 &1 unlike ! planets1 ! motion ( m ?an half ( ^? t h appe>$ has be5 retrograde1 t is1 f ea/ to we/4 ,!y are only visible :5 ne> _! p]ihelia2 !n _! velocity is su*1 t its squ>e is twice z great z t ( a body mov+ 9 a circle at ! same di/ance3 !y consequ5tly rema9 b a v %ort "t )9 ! planet>y orbits4 ,&1 z all ! conic sections ( ! same focal di/ance s5sibly co9cide1 ?r\gh a small arc1 on ea* side ( ! extremity ( _! axis1 x is difficult to asc]ta9 9 :i* ( ^! curves ! comets move1 f obs]vations made1 z !y necess>ily mu/ be1 ne> _! p]ihelia 7,n4 #bbg74 ,probably !y all move 9 extremely exc5tric ellipses2 al?\gh1 9 mo/ cases1 ! p>abolic curve co9cides mo/ ne>ly ) _! obs]v$ motions4 ,"s few seem to describe hyp]bolas2 su*1 be+ once visible to u1 w\ld vani% = ev]1 to w&] ?r\gh b\ndless space1 to ! remote sy/ems ( ! univ]se4 ,if a planet be suppos$ to revolve 9 a circul> orbit1 ^: radius is equal to ! p]ihelion di/ance ( a comet mov+ 9 a p>abola1 ! areas describ$ by ^! two bodies 9 ! same "t w be z unity to ! squ>e root ( two1 :i* =ms su* a connexion betwe5 ! motion ( comets & planets1 t1 by ,kepl]'s law1 ! ratio ( ! areas describ$ dur+ ! same "t by ! comet & ! e>? may be f\nd2 s t ! place ( a comet may be comput$ at any "t 9 its p>abolic orbit1 e/imat$ f ! in/ant ( its passage at ! p]ihelion4 ,x is a problem ( v great difficulty to det]m9e all ! o!r elem5ts ( p>abolic motion--namely1 ! comet's p]ihelion di/ance1 or %orte/ di/ance f ! sun1 e/imat$ 9 p>ts ( ! mean di/ance ( ! e>? f ! sun2 ! longitude ( ! p]ihelion2 ! incl9ation ( ! orbit on ! plane ( ! ecliptic2 & ! longitude ( ! asc5d+ node4 ,?ree obs]v$ longitudes & latitudes ( a comet are suffici5t = comput+ ! approximate values ( ^! quantities2 b an accurate e/imation ( !m c only be obta9$ by successive corrections1 f a numb] ( obs]vations1 di/ant f "o ano!r4 ,:5 ! motion ( a comet is retrograde1 ! place ( ! asc5d+ node is exactly opposite to :at x is :5 ! motion is direct4 ,h5ce ! place ( ! asc5d+ node1 toge!r ) ! direction ( ! comet's motion1 %[ :e!r ! incl9ation ( ! orbit is on ! nor? or s\? side ( ! plane ( ! ecliptic4 ,if ! motion be direct1 ! incl9ation is on ! nor? side2 if retrograde1 x is on ! s\? side4 ,! id5tity ( ! elem5ts is ! only pro( ( ! return ( a comet to our sy/em4 ,%\ld ! elem5ts ( a new comet be ! same1 or ne>ly ! same1 ) ^? ( any "o previ\sly kn[n1 ! probability ( ! id5tity ( ! two bodies is v great1 s9ce ! simil>ity ext5ds to no less ?an f\r elem5ts1 e "o ( :i* is capable ( an inf9ity ( v>iations4 ,b1 ev5 if ! orbit be det]m9$ ) all ! accuracy ! case admits (1 x may be difficult1 or ev5 impossible1 to recognize a comet on its return1 because its orbit w\ld be v mu* *ang$ if x pass$ ne> any ( ! l>ge planets ( ?is or ( any o!r sy/em1 9 consequ5ce ( _! di/urb+ en]gy1 :i* w\ld be v great on bodies ( s r>e a nature4 ,by f> ! mo/ curi\s & int]e/+ in/ance ( ! di/urb+ action ( ! great bodies ( our sy/em is f\nd 9 ! comet ( #aggj4 ,! elem5ts ( its orbit1 det]m9$ by ,messi]1 did n agree ) ^? ( any comet t _h hi!rto be5 comput$1 yet ,lexel asc]ta9$ t x describ$ an ellipse ab\t ! sun1 ^: major axis 0 only equal to ?ree times ! l5g? ( ! diamet] ( ! t]re/rial orbit1 & consequ5tly t x mu/ return to ! sun at int]vals ( five ye>s & a half4 ,?is result 0 confirm$ by num]\s obs]vations1 z ! comet 0 visible ?r\gh an arc ( #agj2 yet ?is comet _h nev] be5 obs]v$ be=e ! ye> #aggj1 nor has x ev] aga9 be5 se5 till #ahdc1 ?\gh v brilliant4 ,! di/urb+ action ( ! l>g] planets af=ds a solution ( ?is anomaly1 z ,lexel asc]ta9$ t 9 #agfg ! comet mu/ h pass$ ,jupit] at a di/ance less ?an ! fifty-eigh? "p ( its di/ance f ! sun1 & t 9 #aggi x w\ld be #ejj times ne>] ,jupit] ?an ! sun2 consequ5tly ! action ( ! sun on ! comet w\ld n be ! fiftie? "p ( :at x w\ld exp]i5ce f ,jupit]1 s t ,jupit] became ! primum mobile4 ,assum+ ! orbit to be su* z ,lexel _h det]m9$ 9 #aggj1 ,la ,place f\nd t ! action ( ,jupit]1 previ\s to ! ye> #aggj1 _h s completely *ang$ ! =m ( x1 t ! comet :i* _h be5 invisible to u be=e #aggj 0 !n br\ght into view1 & t ! action ( ! same planet1 produc+ a contr>y effect1 has subsequ5tly to t ye> remov$ x f our sight1 s9ce x 0 comput$ to be revolv+ 9 an orbit ^: p]ihelion 0 beyond ! orbit ( ,c]es4 ,h[ev]1 ! action ( ,jupit] dur+ ! summ] ( #ahdj mu/ h be5 s great1 f 8 proximity to t s+ul> body1 t he seems to h br\ght x back to its =m] pa? z he _h done 9 #agfg1 = ! elem5ts ( ! orbit ( a comet :i* 0 discov]$ 9 ,novemb] #ahdc1 by ,m4 ,faye1 agree s ne>ly ) ^? ( ! orbit ( ,lexel's comet t ! two bodies 7 suppos$ to be id5tical2 by ! subsequ5t computation ( ,m4 le ,v]ri]1 x appe>s1 h[ev]1 t !y are n ! same1 t !y 7 bo? br\ght to our sy/em by ,jupit]'s attraction1 & t !y h be5 9 x m ?an a c5tury1 & h frequ5tly come ne> ! e>? )\t hav+ be5 se54 ,f ! smallness ( ! exc5tricity ( ,lexel's comet1 ! orbit resembles ^? ( ! planets1 b ?is comet is liable to great] p]turbations ?an any o!r body 9 ! sy/em1 because x comes v ne> ! orbit ( ,m>s :5 9 p]ihelion1 & v ne> t ( ,jupit] :5 9 aphelion2 besides1 x passes )9 a comp>atively small di/ance ( ! orbits ( ! m9or planets2 & z x w cont9ue to cross ! orbit ( ,jupit] at ea* revolution till ! two bodies meet1 its p]iodic "t1 n[ ab\t sev5 ye>s1 w aga9 be *ang$1 b 9 ! mean "t x ought to h return$ to its p]ihelion 9 ! ye> #ahea4 ,?is comet might h be5 se5 f ! e>? 9 #aggf1 _h its light n be5 eclips$ by t ( ! sun4 ,!re is /ill s mu* d\bt ) reg>d to ,lexel's comet t dur+ ! pres5t ye>1 #aheh1 ,m4 le ,v]ri] has con/ruct$ a table ( all ! orbits 9 :i* ! comet may h mov$ aft] leav+ ,jupit] 9 #aggj1 :i* w enable a/ronom]s to recognise ! comet ev5 %\ld ! elem5ts ( its orbit be mu* alt]$4 ,he ?9ks x possible t its pa? may h become hyp]bolic1 b t x is m likely an augm5tation ( its p]iodic "t may h tak5 place4 ,x is q possible t comets frequ5t+ our sy/em may be turn$ away1 or o!rs br\ght to ! sun1 by ! attraction ( planets revolv+ beyond ! orbit ( ,neptune1 or by bodies /ill f>!r remov$ f ! sol> influ5ce4 ,o!r comets1 liable to less di/urbance1 return to ! sun at /at$ int]vals4 ,halley comput$ ! elem5ts ( ! orbit ( a comet t appe>$ 9 ! ye> #afhb1 :i* agre$ s ne>ly ) ^? ( ! comets ( #afjg & #aeca1 t he conclud$ x to be ! same body return+ to ! sun at int]vals ( ab\t sev5ty-five ye>s4 ,he consequ5tly pr$ict$ its reappe>ance 9 ! ye> #ageh1 or 9 ! beg9n+ ( #agei4 ,sci5ce 0 n suffici5tly advanc$ 9 ! "t ( ,halley to enable him to det]m9e ! p]turbations ?is comet might exp]i5ce2 b ,clairaut comput$ t1 9 consequ5ce ( ! attraction ( ,jupit] & ,saturn1 its p]iodic "t w\ld be s mu* %ort] ?an dur+ its revolution betwe5 #afjg & #afhb1 t x w\ld pass its p]ihelion on ! #ah? ( ,april1 #agei4 ,! comet did arrive at t po9t ( its orbit on ! #ab? ( ,m>*1 :i* 0 ?irty-sev5 days be=e ! "t assign$4 ,clairaut subsequ5tly r$uc$ ! error to tw5ty-?ree days2 & ,la ,place has s9ce %[n t x w\ld only h be5 ?irte5 days if ! mass ( ,saturn _h be5 z well kn[n z x is n[4 ,x appe>s1 f ?is1 t ! pa? ( ! comet 0 n q kn[n at t p]iod2 &1 al?\gh _m obs]vations 7 !n made1 !y 7 f> f atta9+ ! accuracy ( ^? ( ! pres5t day4 ,besides1 s9ce ! ye> #agei1 ! orbit ( ! comet has be5 alt]$ by ! attraction ( ,jupit] 9 "o direction1 & t ( ,saturn1 ,uranus1 & ,neptune 9 ! o!r2 yet1 not)/&+ ^! s\rces ( unc]ta9ty1 & our ignorance ( all ! possible causes ( d]angem5t f unkn[n bodies on ! conf9es ( our sy/em1 or 9 ! regions beyond x1 ! comet appe>$ exactly at ! "t1 & n f> f ! place assign$ to x by a/ronom]s2 & its actual arrival at its p]ihelion a little be=e noon on ! #af? ( ,novemb]1 #ahce1 only diff]$ f ! comput$ "t by a v few days1 :i* 0 probably ow+ to ! attraction ( ,neptune4 ,! fulfilm5t ( ?is a/ronomical pr$iction is truly wond]ful1 if x be consid]$ t ! comet is se5 only = a few weeks dur+ its passage ?r\gh our sy/em1 & t x w&]s f ! sun = sev5ty-five ye>s to twice ! di/ance ( ,uranus4 ,?is enorm\s orbit is f\r times long] ?an x is broad2 its l5g? is ab\t #cdbj millions ( miles1 or ab\t ?irty-six times ! mean di/ance ( ! e>? f ! sun4 ,at its p]ihelion ! comet comes )9 ne>ly fifty-sev5 millions ( miles ( ! sun1 & at its aphelion x is sixty times m di/ant4 ,on acc\nt ( ?is ext5sive range x mu/ exp]i5ce #cfjj times m light & heat :5 ne>e/ to ! sun ?an 9 ! mo/ remote po9t ( its orbit4 ,9 ! "o position ! sun w seem to be f\r times l>g] ?an he appe>s to u1 & at ! o!r he w n be app>5tly l>g] ?an a /> 7,n4 #bbh47 ,on ! fir/ appe>ance ( ,halley's comet1 e>ly 9 ,augu/ #ahce1 x seem$ to be m]ely a globul> mass ( dim vap\r1 )\t a tail4 ,a conc5tration ( light1 a little on "o side ( ! c5tre1 increas$ z ! comet approa*$ ! sun & e>?1 & latt]ly look$ s l ! disc ( a small planet1 t x might h be5 mi/ak5 = a solid nucleus4 ,m4 ,/ruve1 h[ev]1 saw a c5tral occultation ( a /> ( ! n9? magnitude by ! comet1 at ,dorpat1 on ! #bi? ( ,septemb]4 ,! /> rema9$ con/antly visible1 )\t any consid]able dim9ution ( light2 &1 in/ead ( be+ eclips$1 ! nucleus ( ! comet disappe>$ at ! mom5t ( conjunction f ! brilliancy ( ! />4 ,! tail increas$ z ! comet approa*$ its p]ihelion1 & %ortly be=e x 0 lo/ 9 ! sun's rays x 0 betwe5 ?irty & =ty degrees 9 l5g?4 ,accord+ to ! obs]vations ( ,m4 ,valz1 ! nebulosity increas$ 9 magnitude z x approa*$ ! sun2 b no o!r comet on record has exhibit$ su* sudd5 & unacc\ntable *anges ( aspect4 ,x 0 invisible = two mon?s :5 ne> its p]ihelion passage1 & :5 x reappe>$ on ! #bd? ( ,janu>y1 #ahcf1 its aspect 0 completely *ang$2 x _h no tail1 & to ! nak$ eye 0 l a hazy />2 b ) a p[]ful telescope x pres5t$ a small1 r\nd1 planet>y-look+ nucleus #b 9 diamet]1 surr\nd$ by an ext5sive coma1 & 9 ! c5tre x _h a small1 bright1 solid "p4 ,! nucleus1 cle> & well def9$1 l ! disc ( a planet1 0 obs]v$ on "o occasion to become obscure & enl>g$ 9 ! c\rse ( a few h\rs4 ,b by f> ! mo/ rem>kable circum/ance 0 ! sudd5 appe>ance ( c]ta9 lum9\s bru%es or sectors1 div]g+ f ! c5tre ( ! nucleus ?r\gh ! nebulosity4 ,m4 ,/ruve describes ! nucleus ( ! comet1 9 ! beg9n+ ( ,octob]1 z elliptical1 & l a burn+ coal1 out ( :i* !re issu$1 9 a direction ne>ly opposite to ! tail1 a div]g5t flame1 v>y+ 9 int5sity1 =m1 & direction1 appe>+ occasionally ev5 d\ble1 & sugge/+ ! idea ( lum9\s gas bur/+ f ! nucleus4 ,on "o occasion ,m4 ,arago saw ?ree ( ^! div]g5t flames on ! side opposite ! tail1 ris+ ?r\gh ! nebulosity1 :i* !y greatly exce$$ 9 brilliancy3 aft] ! comet _h pass$ its p]ihelion1 x acquir$ ano!r ( ^! lum9\s fans1 :i* 0 obs]v$ by ,sir ,john ,h]s*el at ! ,cape ( ,good ,hope4 ,hevelius describes an appe>ance precisely simil>1 :i* he _h witness$ 9 ?is comet at its approa* to ! sun 9 ! ye> #afhb1 & some?+ ( ! k9d seems to h be5 notic$ 9 ! comet ( #agdd4 ,possibly ! second tail ( ! comet ( #agbd1 :i* 0 direct$ t[>ds ! sun1 may h be5 ( ?is nature4 ,! influ5ce ( ! e!real m$ium on ! motions ( ,halley's comet w be kn[n aft] ano!r revolution1 & future a/ronom]s w le>n1 by ! accuracy ( its returns1 :e!r x has met ) any unkn[n cause ( di/urbance 9 its di/ant j\rney4 ,undiscov]$ planets1 beyond ! visible b\nd>y ( our sy/em1 may *ange its pa? & ! p]iod ( its revolution1 & ?us may indirectly reveal to u _! exi/5ce1 & ev5 _! physical nature & orbit4 ,! secrets ( ! yet m di/ant heav5s may be disclos$ to future g5]ations by comets :i* p5etrate /ill f>!r into space1 su* z t ( #agfc1 :i*1 if any fai? may be plac$ 9 ! computation1 goes ne>ly =ty-?ree times f>!r f ! sun ?an ,halley's does1 & %[s t ! sun's attraction is p[]ful en\gh1 at ! enorm\s di/ance ( #ae1ejj millions ( miles1 to recall ! comet to its p]ihelion4 ,! p]iods ( "s comets are said to be ( _m ?\s& ye>s1 & ev5 ! av]age "t ( ! revolution ( comets g5]ally is ab\t a ?\s& ye>s2 :i* proves t ! sun's gravitat+ =ce ext5ds v f>4 ,la ,place e/imates t ! sol> attraction is felt ?r\gh\t a sph]e ^: radius is a hundr$ millions ( times great] ?an ! di/ance ( ! e>? f ! sun4 ,au!ntic records ( ,halley's comet d n ext5d beyond ! ye> #adef1 yet x may be trac$1 ) "s degree ( probability1 ev5 to a p]iod prec$+ ! ,*ri/ian era4 ,b z ! evid5ce only re/s ^u co9cid5ces ( its p]iodic "t1 :i* may v>y z mu* z eighte5 mon?s f ! di/urb+ action ( ! planets1 its id5tity ) comets ( su* remote times mu/ be reg>d$ z extremely d\btful4 ,?is is ! fir/ comet ^: p]iodicity has be5 e/abli%$4 ,x is also ! fir/ ^: elem5ts h be5 det]m9$ f obs]vations made 9 ,europe2 =1 al?\gh ! comets :i* appe>$ 9 ! ye>s #bdj1 #eci1 #efe1 & #hcg1 are ! mo/ anci5t ( ^? ^: orbits h be5 trac$1 _! elem5ts 7 comput$ f ,*9ese obs]vations4 ,besides ,halley's & ,lexel's comets1 t5 or twelve o!rs are n[ kn[n to =m "p ( ! sol> sy/em2 t is to say1 !y return to ! sun at /at$ p]iods4 ,six ( !m h p]iods ( less ?an eight ye>s4 ,t g5]ally call$ ,encke's comet1 or ! comet ( ! %ort p]iod1 0 fir/ se5 by ,,mm4 ,messi] & ,me*a9 9 #aghf1 aga9 by ,miss ,h]s*el 9 #ahje1 & its returns1 9 ! ye>s #ahje & #ahai1 7 obs]v$ by o!r a/ronom]s1 "u ! impression t all f\r 7 diff]5t bodies4 ,h[ev]1 ,pr(essor ,encke n only prov$ _! id5tity1 b det]m9$ ! circum/ances ( ! comet's motion4 ,its reappe>ance 9 ! ye>s #ahbe1 #ahbh1 & #ahcb1 accord$ ) ! orbit assign$ by ,m4 ,encke1 :o ?us e/abli%$ ! l5g? ( its p]iod to be #abjd days1 ne>ly4 ,?is comet is v small1 ( feeble light1 & invisible to ! nak$ eye1 except "u v fav\rable circum/ances1 & 9 p>ticul> positions4 ,x has no tail1 x revolves 9 an ellipse ( great exc5tricity incl9$ at an angle ( #ac #bb to ! plane ( ! ecliptic1 & is subject to consid]able p]turbations f ! attraction ( ! planets1 :i* occasion v>iations 9 its p]iodic "t4 ,among ! _m p]turbations to :i* ! planets are liable1 _! mean motions1 & !re=e ! major axes ( _! orbits1 exp]i5ce no *ange2 :ile1 on ! contr>y1 ! mean motion ( ! moon is accel]at$ f age to age--a circum/ance at fir/ attribut$ to ! resi/ance ( an e!real m$ium p]vad+ space1 b subsequ5tly prov$ to arise f ! secul> dim9ution ( ! exc5tricity ( ! t]re/rial orbit4 ,al?\gh ! resi/ance ( su* a m$ium has n hi!rto be5 p]ceiv$ 9 ! motions ( su* d5se bodies z ! planets & satellites1 its effects on ! revolutions ( ! comets leave no d\bt ( its exi/5ce4 ,f ! num]\s obs]vations t h be5 made on ea* return ( ! comet ( ! %ort p]iod1 ! elem5ts h be5 comput$ ) great accuracy on ! hypo!sis ( its mov+ 9 vacuo4 ,its p]turbations occasion$ by ! di/urb+ action ( ! planets h be5 det]m9$2 &1 aft] ev]y?+ t c\ld influ5ce its motion _h be5 duly consid]$1 ,m4 ,encke f\nd t an accel]ation ( ab\t two days 9 ea* revolution has tak5 place 9 its mean motion1 precisely simil> to t :i* w\ld be occasion$ by ! resi/ance ( an e!real m$ium4 ,&1 z x _c be attribut$ to a cause l t :i* produces ! accel]ation ( ! moon1 x mu/ be conclud$ t ! cele/ial bodies d n p]=m _! revolutions 9 an absolute void1 & t1 al?\gh ! m$ium be too r>e to h a s5sible effect on ! masses ( ! planets & satellites1 x nev]!less has a consid]able influ5ce on s r>e a body z a comet4 ,contradictory z x may seem t ! motion ( a body %\ld be accel]at$ by ! resi/ance ( an e!real m$ium1 ! tru? becomes evid5t if x be consid]$ t bo? planets & comets are reta9$ 9 _! orbits by two =ces :i* exactly balance "o ano!r2 namely1 ! c5trifugal =ce produc+ ! velocity 9 ! tang5t1 & ! attraction ( ! gravitat+ =ce direct$ to ! c5tre ( ! sun4 ,if "o ( ^! =ces be dim9i%$ by any cause1 ! o!r w be proportionally increas$4 ,n[1 ! necess>y effect ( a resi/+ m$ium is to dim9i% ! tang5tial velocity1 s t ! balance is de/roy$1 gravity prepond]ates1 ! body desc5ds t[>ds ! sun till equilibrium is aga9 re/or$ betwe5 ! two =ces2 &1 z x !n describes a small] orbit1 x moves ) increas$ velocity4 ,?us1 ! resi/ance ( an e!real m$ium actually accel]ates ! motion ( a body2 b1 z ! resi/+ =ce is conf9$ to ! plane ( ! orbit1 x has no influ5ce :atev] on ! incl9ation ( ! orbit1 or on ! place ( ! nodes4 ,9 comput+ its effect1 ,m4 ,encke assum$ ! increase to be inv]sely z ! squ>e ( ! di/ance1 & t its resi/ance acts z a tang5tial =ce proportional to ! squ>es ( ! comet's actual velocity 9 ea* po9t ( its orbit4 ,ano!r comet belong+ to our sy/em1 :i* returns to its p]ihelion aft] a p]iod ( #f-c_/d ye>s1 has be5 accel]at$ 9 its motion by a :ole day dur+ "o revolution1 :i* puts ! exi/5ce ( e!r beyond a d\bt1 & confirms ! undulatory !ory ( light4 ,s9ce ?is comet1 :i* revolves ne>ly betwe5 ! orbits ( ! e>? & ,jupit]1 is only accel]at$ "o day at ea* revolution1 :ile ,encke's1 revolv+ ne>ly betwe5 ! orbits ( ,m]cury & ,pallas1 is accel]at$ two1 ! e!real m$ium mu/ increase 9 d5sity t[>ds ! sun4 ,! comet 9 "q 0 discov]$ by ,m4 ,biela at ,joseph/adt on ! #bg? ( ,febru>y1 #ahbf1 & t5 days aft]w>ds x 0 se5 by ,m4 ,gamb>t at ,m>seilles1 :o comput$ its p>abolic elem5ts1 & f\nd t !y agre$ ) ^? ( ! comets :i* _h appe>$ 9 ! ye>s #aghi & #agie1 :5ce he conclud$ !m to be ! same body mov+ 9 an ellipse1 & accompli%+ its revolution 9 #bdfj days4 ,! p]turbations ( ?is comet 7 comput$ by ,m4 ,damoiseau1 :o pr$ict$ t x w\ld cross ! plane ( ! ecliptic on ! #bi? ( ,octob]1 #ahcb1 a little be=e midnight1 at a po9t ne>ly #ah1dhd miles )9 ! e>?'s orbit2 & z ,m4 ,olb]s ( ,brem51 9 #ahje1 _h det]m9$ ! radius ( ! comet's head to be ab\t #ba1acf miles1 x 0 evid5t t its nebulosity w\ld envelop a portion ( ! e>?'s orbit1--a circum/ance :i* caus$ "s al>m 9 ,france1 f ! notion t1 if any di/urb+ cause _h delay$ ! arrival ( ! comet = "o mon?1 ! e>? mu/ h pass$ ?r\gh its head4 ,m4 ,arago dispell$ ^! fe>s by 8 excell5t treatise on comets1 9 ! ,annuaire ( #ahcb1 :]e he proves t1 z ! e>? w\ld nev] be ne>] ! comet ?an #ah1jjj1jjj ,briti% leagues1 !re c\ld be no dang] ( collision4 ,! e>? is 9 m dang] f ^! two small comets ?an f any o!r4 ,encke's crosses ! t]re/rial orbit sixty times 9 a c5tury1 & may ultimately come into collision1 b bo? are s extremely r>e1 t little injury is to be appreh5d$4 ,! e>? w\ld fall to ! sun 9 #fd-a_/b days1 if x 7 /ruck by a comet ) suffici5t impetus to de/roy its c5trifugal =ce4 ,:at ! e>?'s primitive velocity may h be5 x is impossible to say4 ,!re=e a comet may h giv5 x a %ock )\t *ang+ ! axis ( rotation1 b only de/roy+ "p ( its tang5tial velocity1 s z to dim9i% ! size ( ! orbit--a ?+ by no means impossible1 ?\gh highly improbable4 ,at all ev5ts1 !re is no pro( ( ?is hav+ occurr$2 & x is manife/ t ! axis ( ! e>?'s rotation has n be5 *ang$1 because1 z ! e!r (f]s no s5sible resi/ance to s d5se a body z ! e>?1 ! libration w\ld to ?is day be evid5t 9 ! v>iation x mu/ h occasion$ 9 ! t]re/rial latitudes4 ,suppos+ ! nucleus ( a comet to h a diamet] only equal to ! f\r? "p ( t ( ! e>?1 & t its p]ihelion is ne>] to ! sun ?an we are ourselves1 its orbit be+ o!rwise unkn[n1 ,m4 ,arago has comput$ t ! probability ( ! e>? receiv+ a %ock f x is only "o 9 #bha millions1 & t ! *ance ( our com+ 9 contact ) its nebulosity is ab\t t5 or twelve times great]4 ,only comets ) retrograde motions c come into direct collision ) ! e>?1 & if ! mom5tum 7 great ! ev5t might be fatal2 b 9 g5]al ! sub/ance ( comets is s r>e1 t x is likely !y w\ld n d mu* h>m if !y 7 to imp+e2 & ev5 !n ! mis*ief w\ld probably be local1 & ! equilibrium soon re/or$1 provid$ ! nucleus 7 gase\s1 or v small4 ,x is1 h[ev]1 m probable t ! e>? w\ld only be deflect$ a little f its c\rse by ! approa* ( a comet1 )\t be+ t\*$ by x4 ,! comets t h come ne>e/ to ! e>? 7 t ( ! ye> #hcg1 :i* rema9$ f\r days )9 less ?an #a1bdj1jjj leagues f our orbit3 t ( #aggj1 :i* approa*$ )9 ab\t six times ! di/ance ( ! moon4 ,! celebrat$ comet ( #afhj also came v ne> to u2 & ! comet ^: p]iod is #f-c_/d ye>s 0 t5 times ne>] ! e>? 9 #ahje ?an 9 #ahcb1 :5 x caus$ s mu* al>m4 ,encke's & ,biela's comets are at pres5t f> remov$ f ! influ5ce ( ,jupit]1 b !y w n always rema9 s1 because1 ! aphelia & nodes ( ! orbits ( ^! two comets be+ ! po9ts :i* approa* ne>e/ to ! orbit ( ,jupit] at ea* meet+ ( ! planet & comets1 ! major axis ( ,encke's comet w be increas$ & t ( ,biela's dim9i%$1 till 9 ! c\rse ( "t1 :5 ! proximity has increas$ suffici5tly1 ! orbits w be completely *ang$1 z t ( ,lexel's 0 9 #aggj4 ,e tw5ty-?ird ye>1 or aft] sev5 revolutions ( ,encke's comet1 its greate/ proximity to ,jupit] takes place1 & at t "t 8 attraction increases ! p]iod ( its revolution by n9e days--a circum/ance :i* took place 9 ! end ( ! ye>s #ahbj & #ahdc4 ,b f ! position ( ! bodies !re is a dim9ution ( ?ree days 9 ! six foll[+ revolutions1 :i* r$uces ! increase to six days 9 sev5 revolutions4 ,?us1 be=e ! ye> #ahai1 ! p]iodic "t ( ,encke's comet 0 #abjd days1 & x 0 #abai days 9 accompli%+ ! revolution t end$ 9 #ahde4 ,by ?is progressive increase ! orbit ( ! comet w rea* t ( ,jupit] 9 sev5 or eight c5turies1 & !n by ! v ne> approa* ( ! two bodies x w be completely *ang$4 ,at pres5t ! ,e>? & ,m]cury h ! mo/ p[]ful influ5ce on ! motions ( ,encke's & ,biela's comets2 & h _h = s long a "t t1 accord+ to ! computation ( ,mr4 ,airy1 ! pres5t orbit ( ! latt] 0 =m$ by ! attraction ( ! ,e>?1 & t ( ,encke's by ! action ( ,m]cury4 ,) reg>d to ! latt] comet1 t ev5t mu/ h tak5 place 9 ,febru>y #aggf4 ,9 #aghf ,encke's comet _h bo? a tail & a nucleus1 n[ x has nei!r2 a s+ul> in/ance ( ! possibility ( _! disappe>ance4 ,x 0 9 p]ihelio 9 #ahee4 ,9 #ahdf ,biela's comet 0 divid$ into two di/9ct bodies1 by :at /range accid5t is altoge!r a my/]y4 ,! nuclei ( ! two comets 7 sep>at$ by ab\t #aej1jjj miles1 & !y travell$ toge!r ) _! tails p>allel1 & an ar* ( light ov] _! heads4 ,till t "t ,biela's comet nev] _h be5 se5 ) a tail4 ,! new head 0 dull at fir/1 b increas$ 9 size & brightness till x surpass$ its companion 9 bo?2 besides1 x _h a bright fla%+ diamond-l po9t 9 its c5tre--gradually x resum$ its dull appe>ance1 & its p]iod 0 comput$ to be eight days long] ?an t ( ! orig9al head4 ,!y _h sep>at$ to a great] di/ance f "o ano!r 9 #ahec1 b 7 /ill travell+ toge!r1 "o hav+ become small] ?an ! o!r4 ,a comet discov]$ by ,m4 ,brors5 ( ,kiel1 on ! #bf? ( ,febru>y1 #ahdf1 came1 on ! #bj? ( ,april foll[+1 ne>ly z close to ,jupit] z 8 f\r? satellite1 :5 ,jupit]'s attraction mu/ h be5 t5 times great] ?an t ( ! sun2 s !re is e reason to believe t ! comet's orbit w be z mu* alt]$ z t ( ,lexel's2 & ano!r discov]$ by ,padre de ,vico at ,rome1 on ! #bbnd ( ,augu/1 w1 9 all probability1 be z mu* di/urb$ by ! same cause4 ,"o ( ! comets f\nd by t a/ronom] has a p]iod :i* v>ies1 accord+ to diff]5t computations1 f #ee to #ii ye>s2 x c]ta9ly has an elliptical orbit4 ,t discov]$ at ,naples by ,mr4 ,pet]s revolves ab\t ! sun 9 #af ye>s2 b ,olb]s's comet ( #ahae mu/ g ne>ly ! same di/ance into space ) ,halley's1 s9ce its p]iod is #gd ye>s4 ,two discov]$ by ,m4 ,brors5 h p]iods1 "o ( #ejj & ! o!r ( #bh ye>s2 b ( ! latt] !re is "s unc]ta9ty4 ,! comet :i* appe>$ 9 #aeif & #ahde has a p]iod ( #bdi ye>s2 & %\ld ,m4 ,argel&]'s computation be accurate1 ! orbit :i* has hi!rto be5 assign$ to ! great comet ( #ahaa mu/ be errone\s1 s9ce he has asc]ta9$ its p]iod to be #cjff ye>s4 ,! great comet ( #abfd1 :i* _h a tail t ext5d$ ov] #ajj ( ! cele/ial vault1 0 obs]v$ & record$ by ! ,*9ese1 & 0 asc]ta9$ to be ! same t _h appe>$ 9 #aeef1 & ( ^: motions obs]vations 7 tak5 at ,vi5na 9 ! reign ( ! ,emp]or ,*>les ,v41 b x 0 !n less brilliant4 ,9 consequ5ce ( ! discov]y ( ! orig9al obs]vations ( ! comet ( #aeef1 by ,fabricius at ,vi5na1 & by ,hell] at ,nuremburg1 ,mr4 ,h9d 0 induc$ to compute its orbit = t ye>2 b aft] mu* lab\r1 aid$ by all ! improv$ me?ods ( calculation1 he f\nd ,hell]'s obs]vations s confus$1 & ev5 errone\s1 t he c\ld n det]m9e ! curve describ$ by ! comet at t "t ) any precision1 & !re=e c\ld only pr$ict t ! epo* ( its return w\ld be "s "t betwe5 #ahdh & #ahfa4 ,be=e comets rea* ! sun !y are r>ely conspicu\s2 b if aft] pass+ _! p]ihelion !y come ne> ! e>?1 !n !y h tails1 & become brilliant 9 consequ5ce ( ! sun's action ^u ! matt] ( :i* !y are =m$4 ,n[ if ! comet 9 "q %\ld pass its p]ihelion betwe5 ! mon?s ( ,m>* & ,octob]1 x possibly may be z rem>kable z ev]2 b %\ld x come ne>e/ to ! sun 9 w9t]1 su* is ! position ( its orbit ) reg>d to ! e>?1 t x may pass unnotic$--:i* is v unlikely1 z se>* is be+ made = x at almo/ all ! obs]vatories 9 ,europe & 9 ! ,unit$ ,/ates4 ,ne>ly ! :ole ( its orbit lies bel[ ! plane ( ! ecliptic1 & f> f ! pa?s ( ! l>g] planets1 b x ext5ds into space m ?an twice ! di/ance ( ,neptune1 or ne>ly six ?\s& millions ( miles f ! sun4 ,comets 9 or ne> _! p]ihelion move ) prodigi\s velocity4 ,t ( #afhj appe>s to h gone half r\nd ! sun 9 t5 h\rs & a half1 mov+ at ! rate ( #hhj1jjj miles an h\r4 ,if its enorm\s c5trifugal =ce _h ceas$ :5 pass+ its p]ihelion1 x w\ld h fall5 to ! sun 9 ab\t ?ree m9utes1 z x 0 !n less ?an #adg1jjj miles f 8 surface4 ,s ne> ! sun1 x w\ld be expos$ to a heat #bg1ejj times great] ?an t receiv$ by ! e>?2 & z ! sun's heat is suppos$ to be 9 proportion to ! int5sity ( 8 light1 x is probable t a degree ( heat s int5se w\ld be suffici5t to conv]t into vap\r e t]re/rial sub/ance ) :i* we are acqua9t$4 ,at ! p]ihelion di/ance ! sun's diamet] w\ld be se5 f ! comet "u an angle ( #gc1 s t ! sun1 view$ f ! comet1 w\ld ne>ly cov] ! :ole ext5t ( ! heav5s f ! horizon to ! z5i?4 ,z ?is comet is presum$ to h a p]iod ( #ege ye>s1 ! major axis ( its orbit mu/ be s great1 t at ! aphelion ! sun's diamet] w\ld only subt5d an angle ( ab\t f\rte5 seconds1 :i* is n s great by half z ! diamet] ( ,m>s appe>s to u :5 9 opposition4 ,! sun w\ld consequ5tly imp>t no heat1 s t ! comet w\ld !n be expos$ to ! temp]ature ( ! e!real regions1 :i* is #bci bel[ ! z]o po9t ( ,fahr5heit4 ,a body ( su* t5uity z ! comet1 mov+ ) su* velocity1 mu/ h met ) great resi/ance f ! d5se atmosph]e ( ! sun1 :ile pass+ s ne> 8 surface at its p]ihelion4 ,! c5trifugal =ce mu/ consequ5tly h be5 dim9i%$1 & ! sun's attraction proportionally augm5t$1 s t x mu/ h come ne>] to ! sun 9 #afhj ?an 9 its prec$+ revolution1 & w\ld subsequ5tly describe a small] orbit4 ,z ?is dim9ution ( its orbit w be repeat$ at ea* revolution1 ! comet w infallibly end by fall+ on ! surface ( ! sun1 unless its c\rse be *ang$ by ! di/urb+ influ5ce ( "s l>ge body 9 ! unkn[n expanse ( creation4 ,our ignorance ( ! actual d5sity ( ! sun's atmosph]e1 ( ! d5sity ( ! comet1 & ( ! p]iod ( its revolution1 r5d]s x impossible to =m any idea ( ! numb] ( c5turies :i* mu/ elapse be=e ?is ev5t takes place4 ,! same cause may affect ! motions ( ! planets1 & ultimately be ! means ( de/roy+ ! sol> sy/em4 ,b1 z ,sir ,john ,h]s*el obs]ves1 !y c\ld h>dly all revolve 9 ! same direction r\nd ! sun = s _m ages )\t impress+ a correspond+ motion on ! e!real m$ium1 :i* may pres]ve !m f ! accumulat$ effects ( its resi/ance4 ,%\ld ?is mat]ial m$ium revolve ab\t ! sun l a vortex1 x w accel]ate ! revolutions ( su* comets z h direct motions1 & ret>d ^? t h retrograde motions4 ,! comet :i* appe>$ unexpect$ly 9 ! beg9n+ ( ! ye> #ahdc 0 "o ( ! mo/ spl5did t ev] visit$ ! sol> sy/em4 ,x 0 9 ! con/ellation ( ,ant9\s 9 ! end ( ,janu>y1 at a di/ance ( #aae millions ( miles f ! e>?1 & x pass$ ?r\gh its p]ihelion on ! #bg? ( ,febru>y1 :5 x 0 lo/ 9 ! sun's rays2 b x began to be visible ab\t ! #crd ( ,m>*1 at :i* "t x 0 ne> ! /> ,iota ,cet1 & its tail ext5d$ t[>ds ! ,h>e4 ,be=e ! passage at ! p]ihelion x _h no tail2 b at t epo* ! tail sudd5ly d>t$ out1 & ext5d$ to a di/ance ( #ahbf millions ( miles 9 ab\t an h\r & a half--a mo/ inexplicable spe$ ( developm5t1 :i* indicates "s p[]ful repulsive =ce at ! mom5t ( ! greate/ proximity to ! sun1 at :i* "t ! tails are =m$4 ,! brightness ( ! comet & ! l5g? ( its tail cont9u$ to increase till ! latt] /ret*$ f> beyond ! con/ellation ( ! ,h>e t[>ds a po9t above ,sirius4 ,/>s 7 di/9ctly se5 ?r\gh x1 & :5 ne> p]ihelion ! comet 0 s bright t x 0 se5 9 cle> sun%9e1 9 ! ,unit$ ,/ates1 l a :ite cl\d4 ,! motion 0 retrograde1 & on leav+ ! sol> sy/em x retreat$ s rapidly at once f ! sun & e>? t x 0 soon lo/ sight ( = want ( light4 ,on ! #a/ ( ,april x 0 betwe5 ! sun & ! e>?1 & only #dj millions ( miles f ! latt]2 & z its tail 0 at lea/ #fj millions ( miles long1 & #bj millions ( miles broad1 we probably pass$ ?r\gh x )\t be+ aw>e ( x4 ,!re is "s discrepancy 9 ! diff]5t computations ( ! elem5ts ( ! orbit1 b 9 ! great] numb] ( cases ! p]ihelion di/ance 0 f\nd to be less ?an ! semidiamet] ( ! sun1 s t ! comet mu/ h graz$ 8 surface1 if x did n actually imp+e obliquely on him4 ,! p]ihelion di/ance ( ?is comet diff]s little f t ( ! great comet ( #affh1 :i* came s ne> ! sun4 ,! motion ( bo? 0 retrograde1 & a c]ta9 resemblance 9 ! two orbits makes x probable t !y are ! same body p]=m+ a revolution 9 #age ye>s4 ,?\gh already s well acqua9t$ ) ! motions ( comets1 we "k no?+ ( _! physical con/itution4 ,a va/ numb]1 especially ( telescopic comets1 are only l cl\ds or masses ( vap\r1 (t5 )\t tails4 ,! head commonly consi/s ( a conc5trat$ mass ( light1 l a planet1 surr\nd$ by a v transp>5t atmosph]e1 & ! :ole1 view$ ) a telescope1 is s diaphan\s1 t ! smalle/ /> may be se5 ev5 ?r\gh ! d5se/ "p ( ! nucleus2 9 g5]al _! solid p>ts1 :5 !y h any1 are s m9ute1 t !y h no s5sible diamet]1 l t ( ! comet ( #ahaa1 :i* appe>$ to ,sir ,william ,h]s*el l a lum9\s po9t 9 ! middle ( ! nebul\s matt]4 ,! nuclei1 :i* seem to be =m$ ( ! d5s] /rata ( t nebul\s matt] 9 successive coat+s1 are sometimes ( great magnitude4 ,^? comets :i* came to ! sun 9 ! ye>s #agii & #ahjg _h nuclei ^: diamet]s measur$ #ahj & #bge leagues respectively1 & ! second comet ( #ahaa _h a nucleus #acej leagues 9 diamet]4 ,x mu/1 h[ev]1 be /at$ t1 z comets are g5]ally at prodigi\s di/ances f ! e>?1 ! solid p>ts ( ! nuclei appe> l m]e po9ts ( light1 s m9ute t x is impossible to measure !m ) any k9d ( accuracy1 s t ! be/ a/ronom]s (t5 diff] 9 ! e/imation ( _! size by "o-half ( ! :ole diamet]4 ,! transit ( a comet across ! sun w\ld af=d ! be/ in=mation ) reg>d to ! nature ( ! nuclei4 ,x 0 comput$ t su* an ev5t 0 to take place 9 ! ye> #ahbg2 un=tunately ! sun 0 hid by cl\ds f ! ,briti% a/ronom]s1 b x 0 exam9$ at ,vivi]s & at ,m>seilles at ! "t ! comet mu/ h be5 project$ on its disc1 b no spot or cl\d 0 to be se51 s t x mu/ h _h no solid "p :atev]4 ,! nuclei ( _m comets :i* seem$ solid & brilliant to ! nak$ eye h be5 resolv$ into m]e vap\r by telescopes ( high p[]s2 9 ,halley's comet !re 0 no solid "p at all4 ,! nebulosity imm$iately r\nd ! nucleus is s diaphan\s1 t x gives little light2 b at a small di/ance ! nebul\s matt] becomes sudd5ly brilliant1 s z to look l a bright r+ r\nd ! body4 ,sometimes !re are two or ?ree ( ^! lum9\s conc5tric r+s sep>at$ by d>k int]vals1 b !y are g5]ally incomplete on ! "p next ! tail4 ,^! annul> appe>ances are an optical effect1 aris+ f a succession ( envelopes ( ! nebul\s matt] ) int]vals betwe5 !m1 ( :i* ! fir/ is sometimes 9 contact ) ! nucleus & sometimes n4 ,! ?ickness ( ^! bright diaphan\s coat+s 9 ! comets ( #agii & #ahjg 0 ab\t #gjjj & #aj1jjj leagues respectively2 & 9 ! fir/ comet ( #ahaa ! lum9\s r+ 0 #hjjj leagues ?ick1 & ! di/ance betwe5 its int]ior surface & ! c5tre ( ! head 0 #aj1jjj leagues4 ,! latt] comet 0 by mu* ! mo/ brilliant t has be5 se5 9 mod]n times2 x 0 fir/ discov]$ 9 ?is c\ntry by ,mr4 ,james ,viet* ( ,in*bonny1 & 0 obs]v$ 9 all its *anges by ,sir ,william ,h]s*el & ,m4 ,olb]s4 ,to ! nak$ eye1 ! head _h ! appe>ance ( an ill-def9$ r\nd mass ( light1 :i* 0 resolv$ into sev]al di/9ct p>ts :5 view$ ) a telescope4 ,a v brilliant int]ior circul> mass ( nebul\s matt] 0 surr\nd$ by a black space hav+ a p>abolic =m1 v di/9ct f ! d>k blue ( ! sky4 ,?is d>k space 0 ( a v appreciable bread?4 ,ext]ior to ! black int]val !re 0 a lum9\s p>abolic cont\r ( consid]able ?ickness1 :i* 0 prolong$ on ea* side 9 two div]g+ bran*es1 :i* =m$ ! bifid tail ( ! comet4 ,sir ,william ,h]s*el f\nd t ! brilliant int]ior circul> mass lo/ ! di/9ctness ( its outl9e z he increas$ ! magnify+ p[] ( ! telescope1 & pres5t$ ! appe>ance ( a m & m diffuse mass ( gre5i% or bluei% gre5 light1 ^: int5sity decreas$ gradually1 n f ! c5tre1 b f an ecc5tric brilliant speck1 suppos$ to be ! truly solid "p ( ! comet4 ,! lum9\s envelope 0 ( a decid$ yell[1 :i* contra/$ /rongly ) ! gre5i% t9t ( ! int]ior nebul\s mass4 ,/>s 7 ne>ly veil$ by ! lum9\s envelope1 :il/1 on ! contr>y1 ,sir ,william ,h]s*el saw ?ree extremely small />s %9+ cle>ly 9 ! black space1 :i* 0 s+ul>ly transp>5t4 ,z ! envelopes 7 =m$ 9 succession z ! comet approa*$ ! sun1 ,sir ,william ,h]s*el conceiv$ !m to be vap\rs rais$ by 8 heat at ! surface ( ! nucleus1 & susp5d$ r\nd x l a vault or dome by ! ela/ic =ce ( an ext5sive & highly transp>5t atmosph]e4 ,9 com+ to ! sun1 ! coat+s began to =m :5 ! comet 0 z di/ant z ! orbit ( ,jupit]1 & 9 its return !y v soon entirely vani%$2 b a new "o 0 =m$ aft] x _h retreat$ z f> z ! orbit ( ,m>s1 :i* la/$ = a few days4 ,inde$1 comets 9 g5]al are subject to sudd5 & viol5t convulsions 9 _! int]ior1 ev5 :5 f> f ! sun1 :i* produce *anges t are visible at enorm\s di/ances1 & baffle all attempts at explanation--probably aris+ f electricity1 or ev5 causes ) :i* we are unacqua9t$4 ,! envelopes surr\nd+ ! nucleus ( ! comet on ! side next to ! sun div]ge on ! opposite side1 :]e !y are prolong$ into ! =m ( a holl[ cone1 :i* is ! tail4 ,two repulsive =ces seem to be conc]n$ 9 produc+ ?is effect2 "o f ! comet & ano!r f ! sun1 ! latt] be+ ! mo/ p[]ful4 ,! envelopes are ne>] ! c5tre ( ! comet on ! side next to ! sun1 :]e ^! =ces are oppos$ to "o ano!r2 b on ! o!r side ! =ces conspire to =m ! tail1 convey+ ! nebul\s p>ticles to enorm\s di/ances4 ,! lat]al edges ( ! tail reflect m light ?an ! c5tral "p1 because ! l9e ( vision passes ?r\gh a great] dep? ( nebul\s matt]1 :i* produces ! effect ( two /reams some:at l ! aurora4 ,/>s %9e ) undim9i%$ lu/re ?r\gh ! c5tral "p ( ! tail1 because _! rays trav]se x p]p5dicul>ly to its ?ickness2 b1 ?\gh di/9ctly se5 ?r\gh its edges1 _! light is weak5$ by its oblique transmission4 ,! tail ( ! great comet ( #ahaa 0 ( wond]ful t5uity2 />s :i* w\ld h be5 entirely conceal$ by ! slighte/ fog 7 se5 ?r\gh #fd1jjj leagues ( nebul\s matt] )\t ! smalle/ refraction4 ,possibly "s "p ( ! *anges 9 ! appe>ance ( ! tails arises f rotation4 ,sev]al comets h be5 obs]v$ to rotate ab\t an axis pass+ ?r\gh ! c5tre ( ! tail4 ,t ( #ahbe p]=m$ its rotation 9 #bj-a_/b h\rs1 & ! rapid *anges 9 ! lum9\s sectors :i* issu$ f ! nucleus ( ,halley's comet 9 all probability 7 ow+ to rotatory motion4 ,! two /reams ( light :i* =m ! edges ( ! tail 9 mo/ cases unite at a great] or less di/ance f ! nucleus1 & are g5]ally situate 9 ! plane ( ! orbit4 ,! tails foll[ comets 9 _! desc5t t[>ds ! sun1 b prec$e !m 9 _! return1 ) a small degree ( curvature2 _! app>5t ext5t & =m v>y accord+ to ! positions ( ! orbits ) reg>d to ! ecliptic4 ,9 "s cases ! tail has be5 at "r angles to ! l9e jo9+ ! sun & comet4 ,! curvature is 9 "p ow+ to ! resi/ance ( ! e!r1 & p>tly to ! velocity ( ! comet be+ great] ?an t ( ! p>ticles at ! extremity ( its tail1 :i* lag beh9d4 ,! tails are g5]ally ( enorm\s l5g?s2 ! comet ( #ahaa _h "o no less ?an a hundr$ millions ( miles 9 l5g?1 & ^? :i* appe>$ 9 ! ye>s #afah1 #afhj1 & #agfi1 _h tails :i* ext5d$ respectively ov] #ajd1 #ij1 & #ig degrees ( space4 ,consequ5tly1 :5 ! heads ( ^! comets 7 set1 a portion ( ! extremity ( _! tails 0 /ill 9 ! z5i?4 ,sometimes ! tail is divid$ into sev]al bran*es1 l ! comet ( #agdd1 :i* _h six1 sep>at$ by d>k int]vals1 ea* ( !m ab\t #d broad1 & f #cj to #dd long4 ,!y 7 probably =m$ by ?ree holl[ cones ( ! nebul\s matt] proce$+ f ! diff]5t envelopes1 & enclos+ "o ano!r1 ) int]vals betwe52 ! lat]al edges ( ^! cones w\ld give ! appe>ance ( six /reams ( light4 ,! tails d n atta9 _! full magnitude till ! comet has left ! sun4 ,:5 comets fir/ appe>1 !y resemble r\nd films ( vap\r1 ) little or no tail4 ,z !y approa* ! sun1 !y increase 9 brilliancy1 & _! tail 9 l5g?1 till !y are lo/ 9 8 rays2 & x is n till !y em]ge f ! sun's m vivid light t !y assume _! full spl5d\r4 ,!y !n gradually decrease1 _! tails dim9i%1 & !y disappe>1 ne>ly or altoge!r1 be=e !y are beyond ! sph]e ( telescopic vision4 ,_m comets h no tails1 z1 = example1 ,encke's comet4 ,^? :i* appe>$ 9 ! ye>s #aehe1 #agfc1 & #afhb1 7 also )\t tails1 ?\gh ! latt] is record$ to h be5 z bright z ,jupit]4 ,! matt] ( ! tail mu/ be extremely buoyant to prec$e a body mov+ ) su* velocity3 inde$1 ! rapidity ( its asc5t _c be acc\nt$ =4 ,x has be5 attribut$ to t p[] 9 ! sun :i* produces ^? vibrations ( e!r :i* con/itute light2 b z ?is !ory w n acc\nt = ! comet ( #ahbd1 :i* is said to h _h two tails1 "o direct$ t[>ds ! sun1 & a v %ort "o diametrically opposite to x1 our ignorance on ?is subject mu/ be confess$4 ,9 ?is case ! repell+ p[] ( ! comet seems to h be5 great] ?an t ( ! sun4 ,:atev] t unkn[n p[] may be1 !re are in/ances 9 :i* its effects are enorm\s2 =1 imm$iately aft] ! great comet ( #afhj _h pass$ its p]ihelion1 its tail 0 #ajj1jjj1jjj miles 9 l5g?1 & 0 project$ f ! comet's head 9 ! %ort space ( two days4 ,a body ( su* extreme t5uity z a comet is mo/ likely incapable ( an attraction p[]ful en\gh to recall matt] s5t to su* an enorm\s di/ance2 x is !re=e1 9 all probability1 scatt]$ 9 space or absorb$ by ! zodiacal light or nebula t surr\nds ! sun1 :i* may acc\nt = ! rapid decrease obs]v$ 9 ! tails ( comets e "t !y return to _! p]ihelia4 ,%\ld ! great comet ( #ahdc prove to be ! same ) t ( #affh1 its tail mu/ h dim9i%$ consid]ably4 ,x is rem>kable t1 al?\gh ! tails ( comets increase 9 l5g? z !y approa* _! p]ihelia1 !re is reason to believe t ! real diamet] ( ! head contracts on com+ ne> ! sun1 & exp&s rapidly on leav+ him4 ,hevelius fir/ obs]v$ ?is ph5om5on1 :i* ,encke's comet has exhibit$ 9 a v extraord9>y degree4 ,on ! #bh? ( ,octob]1 #ahbh1 ?is comet 0 ab\t ?ree times z f> f ! sun z x 0 on ! #bd? ( ,decemb]2 yet at ! fir/ date its app>5t diamet] 0 tw5ty-five times great] ?an at ! second1 ! decrease be+ progressive4 ,m4 ,valz attributes ! circum/ance to a real cond5sation ( volume f ! pressure ( ! e!real m$ium1 :i* increases mo/ rapidly 9 d5sity t[>ds ! surface ( ! sun1 & =ms an ext5sive atmosph]e ar\nd him4 ,x did n occur to ,m4 ,valz1 h[ev]1 t ! e!real fluid w\ld p5etrate ! nebul\s matt] in/ead ( compress+ x4 ,sir ,john ,h]s*el1 on ! contr>y1 conjectures t x may be ow+ to ! alt]nate conv]sion ( evaporable mat]ials 9 ! upp] regions ( ! transp>5t atmosph]e ( comets into ! /ates ( visible cl\d & invisible gas by ! effects ( heat & cold2 or t "s ( ! ext]nal nebul\s envelopes may come into view :5 ! comet arrives at a d>k] "p ( ! sky1 :i* 7 ov]p[]$ by ! sup]ior light ( ! sun :ile 9 8 vic9ity4 ,! fir/ ( ^! hypo!ses he consid]s to be p]fectly confirm$ by 8 obs]vations on ,halley's comet1 made at ! ,cape ( ,good ,hope1 aft] its return f ! sun4 ,he ?9ks t1 9 all probability1 ! :ole comet1 except ! d5se/ "p ( its head1 vani%$1 & 0 r$uc$ to a transp>5t & invisible /ate dur+ its passage at its p]ihelion3 = :5 x fir/ came into view1 aft] leav+ ! sun1 x _h no tail1 & its aspect 0 completely *ang$4 ,a p>abolic envelope soon began to appe>1 & increas$ s mu* & s rapidly t its augm5tation 0 visible to ! eye4 ,?is increase cont9u$ till x became s l>ge & s fa9t1 t at la/ x vani%$ entirely1 leav+ only ! nucleus & a tail1 :i* x _h aga9 acquir$1 b :i* also vani%$2 s t at la/ ! nucleus alone rema9$4 ,n only ! tails1 b ! nebul\s "p ( comets1 dim9i%es e "t !y return to _! p]ihelia2 aft] frequ5t returns !y ought to lose x altoge!r1 & pres5t ! appe>ance ( a fix$ nucleus3 ?is ought to happ5 soon] to comets ( %ort p]iods4 ,m4 de la ,place supposes t ! comet ( #afhb mu/ be approa*+ rapidly to t /ate4 ,%\ld ! sub/ances be altoge!r1 or ev5 to a great degree1 evaporat$1 ! comet w\ld disappe> = ev]4 ,possibly comets may h vani%$ f our view soon] ?an !y w\ld o!rwise h done f ?is cause4 ,! comet discov]$ at ,flor5ce by ,signore ,donati1 on ! #bnd ( ,june1 #aheh1 0 "o ( ! mo/ beautiful t has be5 se5 f our planet = _m ye>s1 :e!r = ! brightness ( ! nucleus1 or ! l5g? & graceful =m ( ! coma2 :5 fir/ discov]$ x 0 ne> ! /> 9 ! con/ellation ( ! ,lion1 be+ !n at a di/ance ( #bhh1jjj1jjj miles f ! e>?2 dur+ ! mon? ( ,augu/ its nucleus assum$ an almo/ planet>y aspect f ! conc5tration ( its light2 on ! #bg? ( ,septemb] ! head appe>$ almo/ z bright z ,m]cury1 b small]2 :5 ne> its p]ihelion passage1 on ,septemb] #cj?1 its diamet]1 z asc]ta9$ by ,signore ,donati1 0 #c2 dur+ ! e>ly "p ( ,octob] x cont9u$ to increase 9 brilliancy1 ! tail becom+ m elongat$1 & describ+ a beautiful arc 9 ! heav5s1 occupy+ a space ( ne>ly #dj1 or a l5g? ( #dj1jjj1jjj miles 9 ! sol> sy/em4 ,on ! ev5+ ( ! #e? ( ,octob] x 0 se5 f mo/ p>ts ( ,brita91 )9 #bj ( ,arcturus1 ! brighte/ /> 9 ! nor!rn heav5s1 across :i* ! d5se/ "p ne>ly ( ! tail pass$1 & ?r\gh :i* not)/&+ ! /> %one ) undim9i%$ brilliancy4 ,on ! #cj? ( ,octob]1 :5 9 p]ihelio1 ! comet 0 only #ee1jjj1jjj miles f ! sun2 on ! #aj? x approa*$ ne>e/ to ! e>?1 f :i* x 0 !n di/ant #ea1jjj1jjj miles2 & on ! #ae? ( ! same mon? ne> to ,v5us1 be+ at t "t less ?an "o-t5? ! di/ance ( ! e>? f ! ,sun2 if ! comet _h rea*$ its p]ihelion a few days e>li]1 ,v5us might h pass$ ?r\gh its nucleus1 ! consequ5ces ( :i* to ! planet x w\ld be v difficult to imag9e4 ,! motion ( ,donati's comet is :at a/ronom]'s call retrograde1 or f ea/ to we/4 ,x ceas$ to be visible 9 our nor!rn latitudes 9 ! la/ week 9 ,octob]1 hav+ pass$ into ! s\!rn heav5s1 :]e x w trav]se ! con/ellations ( ,sagitt>ius1 ,telescopium1 & ,indus1 approa*+ ! l>ge /> ( ,t\can2 aft] :i* x w disappe> until x has ne>ly complet$ its revolution r\nd ! sun4 ,! obs]v$ orbit ( ?is rem>kable comet co9cides m ne>ly ) an ellipse ?an a p>abola2 ! long] diamet] ( ! ellipse be+ #ahd times t ( ! e>?'s orbit1 or ! imm5se di/ance ( #ce1ajj1jjj1jjj miles--a space :i*1 h[ev] great1 is less ?an ! ?\s&? ( ! di/ance ( ! ne>e/ fix$ />4 ,accord+ to ! calculations ( ,m4 ,loewy1 & adopt+ an elliptic orbit1 ,donati's comet w n return to ! same places 9 ! heav5s = #bdie ye>s1 be+ #ejj less ?an ! p]iod ( revolution ( ! great comet ( #ahaa4 ,signore ,donati obs]v$ t betwe5 ! #be? & #cj? ,septemb] two conc5tric1 lum9\s1 semicircul> envelopes1 ) a d>k space betwe5 !m1 7 =m$ 9 ! head4 ,f ! extremities ( ^! ! cone ( ! tail ext5d$1 & a non-lum9\s or d>k space /ret*$ = #bj f ! nucleus into ! tail4 ,on ! #a/ ,octob] ! two envelopes 7 comb9$ into "o4 ,?is comet1 l ,halley's1 has %[n "s s+ul> irregul>ities1 suppos$ to arise f ! action ( ! sun :5 ne> its p]ihelion4 ,at diff]5t p]iods ( its app>ition a viol5t agitation 0 obs]v$ 9 its nucleus1 ) lum9\s jets1 spiral (f%oots1 c41 z 9 ! great comets ( #afhj1 #agdd1 #ahaa4 ,a ray ( light 0 ?r[n out f "o side ( ! nucleus t[>ds ! sun1 :ile a gas-l jet proce$$ f ! o!r side1 :i* appe>$ to =m ! orig9 ( a second tail )9 ! great tail1 & :i* 0 trac$ = half a degree by ,mr4 ,h9d on ! #ai? ,septemb]4 ,he obs]v$ decid$ spiral convolutions 9 ! tail1 :i* %[ t ?is comet has a rotatory motion ab\t an axis pass+ ?r\gh ! tail4 ,if comets %9e by borr[$ light1 !y ought1 9 c]ta9 positions1 to exhibit phases l ! moon2 b no su* appe>ance has be5 detect$1 except 9 "o in/ance1 :5 !y are said to h be5 obs]v$ by ,hevelius & ,la ,hire1 9 ! ye> #afhb4 ,9 g5]al1 ! light ( comets is dull--t ( ! comet ( #ahaa 0 only equal to ! t5? "p ( ! light ( ! full moon--yet "s h be5 brilliant en\gh to be visible 9 full daylight1 especially ! comet ( #agdd1 :i* 0 se5 )\t a telescope at "o o'clock 9 ! aft]noon1 :ile ! sun 0 %9+4 ,h5ce x may be inf]r$ t1 al?\gh "s comets may be altoge!r diaphan\s1 o!rs seem to possess a solid mass resembl+ a planet4 ,b :e!r !y %9e by _! own or by reflect$ light has nev] be5 satisfactorily made out till n[4 ,ev5 if ! light ( a comet 7 pol>iz$1 x w\ld n af=d a decisive te/1 s9ce a body is capable ( reflect+ light1 ?\gh x %9es by its own4 ,m4 ,arago1 h[ev]1 has1 ) great +5uity1 discov]$ a me?od ( asc]ta9+ ?is po9t1 indep5d5t bo? ( phases & pol>ization4 ,s9ce ! rays ( light div]ge f a lum9\s po9t1 !y w be scatt]$ ov] a great] space z ! di/ance increases1 s t ! int5sity ( ! light on a scre5 two feet f ! object is f\r times less ?an at ! di/ance ( "o foot2 ?ree feet f ! object x is n9e times less2 & s on1 decreas+ 9 int5sity z ! squ>e ( ! di/ance increases4 ,z a self-lum9\s surface consi/s ( an inf9ite numb] ( lum9\s po9ts1 x is cle> t1 ! great] ! ext5t ( surface1 ! m int5se w be ! light2 :5ce x may be conclud$ t ! illum9at+ p[] ( su* a surface is proportional to its ext5t1 & decreases inv]sely z ! squ>e ( ! di/ance4 ,not)/&+ ?is1 a self-lum9\s surface1 plane or curv$1 view$ ?r\gh a hole 9 a plate ( metal1 is ( ! same brilliancy at all possible di/ances z long z x subt5ds a s5sible angle1 because1 z ! di/ance increases1 a great] portion comes into view2 &1 z ! augm5tation ( surface is z ! squ>e ( ! diamet] ( ! "p se5 ?r\gh ! :ole1 x increases z ! squ>e ( ! di/ance4 ,h5ce1 ?\gh ! numb] ( rays f any "o po9t ( ! surface :i* pass ?r\gh ! hole decreases inv]sely z ! squ>e ( ! di/ance1 yet1 z ! ext5t ( surface :i* comes into view increases also 9 t ratio1 ! brightness ( ! object is ! same to ! eye z long z x has a s5sible diamet]4 ,= example--,uranus is ab\t n9ete5 times f>!r f ! sun ?an we are1 s t ! sun1 se5 f t planet1 mu/ appe> l a /> ) a diamet] ( a hundr$ seconds1 & mu/ h ! same brilliancy to ! inhabitants t he w\ld h to u if view$ ?r\gh a small circul> hole hav+ a diamet] ( a hundr$ seconds4 ,= x is obvi\s t light comes f e po9t ( ! sun's surface to ,uranus1 :]eas a v small portion ( 8 disc is visible ?r\gh ! hole2 s t ext5t ( surface exactly comp5sates di/ance4 ,s9ce1 !n1 ! visibility ( a self-lum9\s object does n dep5d ^u ! angle x subt5ds z long z x is ( s5sible magnitude1 if a comet %9es by its own light1 x %\ld reta9 its brilliancy z long z its diamet] is ( a s5sible magnitude2 &1 ev5 aft] x has lo/ an app>5t diamet]1 x ought to be visible1 l ! fix$ />s1 & %\ld only vani% 9 consequ5ce ( extreme remot5ess4 ,t1 h[ev]1 is f> f be+ ! case--comets gradually become dim z _! di/ance increases1 & vani% m]ely f loss ( light1 :ile !y /ill reta9 a s5sible diamet]1 :i* is prov$ by obs]vations made ! ev5+ be=e !y disappe>4 ,x may !re=e be conclud$ t comets %9e by reflect+ ! sun's light4 ,! mo/ brilliant comets h hi!rto ceas$ to be visible :5 ab\t five times z f> f ! sun z we are4 ,mo/ ( ! comets t h be5 visible f ! e>? h _! p]ihelia )9 ! orbit ( ,m>s1 because !y are invisible :5 z di/ant z ! orbit ( ,saturn3 on t acc\nt !re is n "o on record ^: p]ihelion is situate beyond ! orbit ( ,jupit]4 ,inde$1 ! comet ( #agef1 aft] its la/ appe>ance1 rema9$ five :ole ye>s )9 ! ellipse describ$ by ,saturn )\t be+ once se54 ,m ?an a hundr$ & =ty comets h appe>$ )9 ! e>?'s orbit dur+ ! la/ c5tury t h n aga9 be5 se54 ,if a ?\s& ye>s be all[$ z ! av]age p]iod ( ea*1 x may be comput$1 by ! !ory ( probabilities1 t ! :ole numb] :i* range )9 ! e>?'s orbit mu/ be #adjj2 b1 ,uranus be+ ab\t n9ete5 times m di/ant1 !re may be no less ?an #aa1bjj1jjj comets t come )9 ! orbit ( ,uranus4 ,m4 ,arago makes a diff]5t e/imate2 he consid]s t1 z ?irty comets are kn[n to h _! p]ihelion di/ance )9 ! orbit ( ,m]cury1 if x be assum$ t comets are uni=mly di/ribut$ 9 space1 ! numb] hav+ _! p]ihelion )9 ! orbit ( ,uranus mu/ be to ?irty z ! cube ( ! radius ( ! orbit ( ,uranus to ! cube ( ! radius ( ! orbit ( ,m]cury1 :i* makes ! numb] ( comets am\nt to #c1ebi1dgj4 ,b t numb] may be d\bl$1 if x be consid]$ t1 9 consequ5ce ( daylight1 fogs1 & great s\!rn decl9ation1 "o comet out ( two mu/ be hid f u4 ,accord+ to ,m4 ,arago1 m ?an sev5 millions ( comets come )9 ! orbit ( ,uranus4 ,! diff]5t degrees ( velocity ) :i* ! planets & comets 7 orig9ally propell$ 9 space is ! sole cause ( ! div]sity 9 ! =m ( _! orbits1 :i* dep5ds only ^u ! mutual relation betwe5 ! projectile =ce & ! sun's attraction4 ,:5 ! two =ces are exactly equal to "o ano!r1 circul> motion is produc$2 :5 ! ratio ( ! projectile to ! c5tral =ce is exactly t ( #a to ! squ>e root ( #b1 ! motion is p>abolic2 any ratio betwe5 ^! two w cause a body to move 9 an ellipse1 & any ratio great] ?an t ( #a to ! squ>e root ( #b w produce hyp]bolic motion 7,n4 #bbi74 ,! cele/ial bodies might move 9 any "o ( ^! f\r curves by ! law ( gravitation3 b1 z "o p>ticul> velocity is necess>y to produce ei!r circul> or p>abolic motion1 su* motions c h>dly be suppos$ to exi/ 9 ! sol> sy/em1 :]e ! bodies are liable to su* mutual di/urbances z w\ld infallibly *ange ! ratio ( ! =ces1 & cause !m to move 9 ellipses 9 ! fir/ case1 & hyp]bolas 9 ! o!r4 ,on ! contr>y1 s9ce e ratio betwe5 equality & t ( #a to ! squ>e root ( #b w produce elliptical motion1 x is f\nd 9 ! sol> sy/em 9 all its v>ieties1 f t :i* is ne>ly circul> to su* z bord]s on ! p>abolic f excessive ellipticity4 ,on ?is dep5ds ! /ability ( ! sy/em2 ! mutual di/urbances only cause ! orbits to become m or less exc5tric )\t *ang+ _! nature4 ,= ! same reason ! bodies ( ! sol> sy/em might h mov$ 9 an inf9ite v>iety ( hyp]bolas1 s9ce any ratio ( ! =ces1 great] ?an t :i* causes p>abolic motion1 w make a body move 9 "o ( ^! curves4 ,hyp]bolic motion is h[ev] v r>e2 only two comets appe> to move 9 orbits ( t nature1 ^? ( #agga & #ahbd2 probably all su* comets h already come to _! p]ihelia1 & consequ5tly w nev] return4 ,! ratio ( ! =ces :i* fix$ ! nature ( ! cele/ial orbits is ?us easily expla9$2 b ! circum/ances :i* det]m9$ ^! ratios1 :i* caus$ "s bodies to move ne>ly 9 circles & o!rs to w&] t[>ds ! limits ( ! sol> attraction1 & :i* made all ! heav5ly bodies to rotate & revolve 9 ! same direction1 mu/ h _h _! orig9 9 ! primeval /ate ( ?+s2 b z x pleases ! ,supreme ,intellig5ce to employ gravitation alone 9 ! ma9t5ance ( ?is fair sy/em1 x may be presum$ to h presid$ at its creation4 ,,section ,,xxxvi4 ,! ,fix$ ,/>s--,_! ,numb]--,! ,milky ,way--,d\ble ,/>s--,b9>y ,sy/ems--,_! ,orbits & ,p]iodic ,times--,col\rs ( ! ,/>s--,/>s t h vani%$--,v>iable ,/>s--,v>iation 9 ,sun's ,light--,p>allax & ,di/ances ( ! ,fix$ ,/>s--,masses ( ! ,/>s--,comp>ative ,light ( ! ,/>s--,prop] ,motions ( ! ,/>s--,app>5t ,motions ( ! ,/>s--,motion & ,velocity ( ! ,sun & ,sol> ,sy/em--,! ,nebul--,_! ,numb]--,catalogue ( !m--,consi/ ( ,two ,classes--,diffuse ,nebul--,def9itely =m$ ,nebul--,globul> ,clu/]s--,spl5d\r ( ,milky ,way--,di/ribution ( ! ,nebul--,! ,magellanic ,cl\ds--,nebul r\nd ,args--,con/itution ( ,nebul1 & ! ,=ces t ma9ta9 !m--,meteorites & ,%oot+ ,/>s4 ,,great z ! numb] ( comets appe>s to be1 x is absolutely no?+ 9 comp>ison ( ! multitude ( ! fix$ />s4 ,ab\t #bjjj only are visible to ! nak$ eye2 b :5 ! heav5s are view$ ?r\gh a telescope1 _! numb] seems to be limit$ only by ! imp]fection ( ! in/rum5t4 ,! numb] regi/]$ am\nts to #bjj1jjj2 _! places are det]m9$ ) great precision1 & !y are =m$ into a catalogue1 n only = ! purpose ( asc]ta9+ geographical positions by ! occultations ( ! brighte/ among !m1 b also to s]ve z po9ts ( ref]5ce = m>k+ ! places ( comets & o!r cele/ial ph5om5a4 ,sirius1 ,c5tauri1 & ,arcturus are ! brighte/ />s 9 ! heav5s2 ! o!rs are class$ accord+ to _! app>5t lu/re1 f ! fir/ to ! sev5te5? magnitudes4 ,capella1 ,lyr1 ,procyon1 & tw5ty or tw5ty-"o m1 are ( ! fir/ magnitude2 ,p]sei1 ,orionis1 ,cygni1 & 9 all fifty or sixty1 are ( ! second2 & ( ! ?ird !re are ab\t #bjj1 su* z ,bootis & ,draconis1 ! numb]s increas+ z ! magnitude dim9i%es4 ,^? ( ! eigh? magnitude are sc>cely visible to ! nak$ eye1 & x requires a v good telescope to see />s ( ! sev5te5?4 ,?is sequ5ce is p]fectly arbitr>y2 b ,sir ,john ,h]s*el has asc]ta9$ by actual measurem5t ! comp>ative lu/re ( a great _m--= example1 he f\nd t ! light ( a /> ( ! six? magnitude is #ajj times less ?an t ( "o ( ! fir/ magnitude1 & t ,sirius w\ld make betwe5 ?ree & f\r hundr$ ( su* little />s4 ,7 ! photometric scale complet$1 x w\ld be ( ! greate/ importance ) reg>d to ! v>iable />s4 ,! ?ree or f\r brighte/ classes ( />s are scatt]$ pretty equably ov] ! sky1 ) ! exception ( a zone or belt foll[+ ! c\rse ( ! great circle pass+ ?r\gh ,orionis & ,crucis1 :]e !y are v num]\s1 especially 9 ! s\!rn hemisph]e4 ,! />s ( all magnitudes visible to ! nak$ eye increase 9 numb]s t[>ds ! bord]s ( ! ,milky ,way1 :i* d]ives its lu/re & "n f ! diffus$ light ( myriads ( />s2 s num]\s are !y 9 "s p>ts ( x t m ?an #ej1jjj pass$ ?r\gh ! field ( ,sir ,william ,h]s*el's telescope 9 ! c\rse ( an h\r1 9 a zone only two degrees broad2 9 _m places !y are num]\s beyond e/imation1 & mo/ ( !m are extremely small on acc\nt ( _! enorm\s di/ances4 ,! ,milky ,way1 :i* =ms s conspicu\s a "p ( ! firmam5t1 is a va/ & some:at flatt5$ /ratum or cong]ies ( />s1 encircl+ ! heav5s 9 a broad b&1 split ?r\gh "o "p ( its circumf]5ce into two /reams ( />s1 be>+ a /rong resemblance to fig4 #e1 plate #e4 ,x is contort$ & brok5 9 "s places1 & occasionally l5g!n$ into bran*es /ret*+ f> into space4 ,its ?ickness is small comp>$ ) its l5g? & bread?2 yet 9 "s places x is unfa?omable ev5 ) ! be/ telescopes2 9 o!rs !re is reason to believe t x is possible to see ?r\gh x1 & ev5 beyond x1 9 its own plane4 ,!re is a gradual b rapid increase 9 ! cr[d+ ( ! />s on ea* side ( ! flat /ratum t[>ds ! c5tre4 ,! sol> sy/em is deeply ?\gh exc5trically plung$ into ?is mass ( />s1 ne> t po9t :]e ! circul> /ratum splits into two /reams4 ,sir ,john ,h]s*el's description ( ! />s ( ! s\!rn hemisph]e %[s t ! ,milky ,way is a mo/ magnific5t object !re4 8,! g5]al aspect ( ! s\!rn circumpol> regions 7includ+ 9 t expression #fj or #gj ( s\? pol> di/ance7 is 9 a high degree ri* & magnific5t1 ow+ to ! sup]ior brilliancy & l>ge developm5t ( ! ,milky ,way1 :i*1 f ! con/ellation ( ,orion to t ( ,ant9\s1 is a blaze ( light1 /rangely int]rupt$1 h[ev]1 ) vacant & entirely />less pat*es1 especially 9 ,scorpio1 ne> ,c5tauri & ! ,cross1 :ile to ! nor? x fades away pale & dim1 & is 9 comp>ison h>dly traceable4 ,i ?9k x is impossible to view ?is spl5did zone1 ) ! a/oni%+ly ri* & ev5ly di/ribut$ fr+e ( />s ( ! #crd & #d? magnitude1 :i* =ms a broad skirt to its s\!rn bord] l a va/ curta91 )\t an impression am\nt+ almo/ to conviction1 t ! ,milky ,way is n a m]e /ratum1 b annul>1 or at lea/ t our sy/em is plac$ )9 "o ( ! poor] or almo/ vacant p>ts ( its g5]al mass1 & t ecc5trically1 s z to be mu* ne>] to ! region ab\t ! ,cross ?an to t diametrically opposite to x40 ,^? d>k vacuities call$ 8,coal ,sacks0 by ! anci5t navigators1 :i* are s num]\s betwe5 ,c5tauri & ,ant>is1 are among ! mo/ extraord9>y ph5om5a 9 ! s\!rn hemisph]e2 !y are ( int5se blackness1 ?\gh by no means void ( extremely small telescopic />s2 ! d>kness arises f ! contra/ ^! ne>ly vacant spaces =m ) ! excessive brilliancy ( ! surr\nd+ "p ( ! ,milky ,way1 & ! sudd5 %>p transition f light to d>kness4 ,! l>ge/ & mo/ conspicu\s ( !m is a pe>-%ap$ vacuity close to ! ,s\!rn ,cross4 ,t portion ( ! ,milky ,way t is split longitud9ally ?r\gh its c5tre lies betwe5 ,c5tauri & ! con/ellation ( ,cygnus3 ! two b&s are jo9$ "h & !re by n>r[ bridges ( cond5s$ />s1 /ret*+ across ! d>k] space betwe5 !m4 ,9 ,scorpio & ,sagitt>ius ,sir ,john ,h]s*el describes ! ,milky ,way z compos$ ( def9ite cl\ds ( light runn+ into clu/]s ( extremely m9ute />s l s&1 n /rew$ ev5ly z ) a sieve1 b z if ?r[n d[n by h&fuls1 & by bo? h&s at once1 leav+ d>k int]vals4 ,9 ?is a/oni%+ pr(usion ! />s are ( all sizes1 f ! #ad? to ! #bj? magnitude1 & ev5 d[n to nebulosity4 ,aft] an int]val ! same pr(usion is r5ew$1 ! />s be+ inconceivably m9ute & num]\s beyond description--!y are 9 millions & millions4 ,?us !re is great irregul>ity 9 _! diffusion z well z magnitude--9 "s places int5sely cr[d$1 9 o!rs ! deep blackness ( ! sky1 ov] :i* !y are ?9ly scatt]$1 irresi/ibly l$ to believe t 9 ^! regions ! p[] ( our telescopes fairly p5etrates ?r\gh ! />ry /ratum1 & beyond x4 ,sometimes we look ?r\gh a %eet ( />s ne>ly ( ! same size1 ( no great ?ickness comp>$ ) _! di/ance f u1 & n unfrequ5tly !re is a d\ble /ratum1 "o ( l>ge />s spread ov] ano!r ( v small ones4 ,! mo/ s\!rly ( ! two /reams ( />s :i* =m ! ,milky ,way 9 ?is "p ( ! firmam5t ma9ta9s an unbrok5 c\rse ( extreme brilliancy1 conta9+ "s ( ! f9e/ clu/]s ( />s 9 ! heav5s4 ,"o r\nd ,sagitt>ii is an int5se aggregate ( />s1 9 "s p>ts ( :i* !y are s cr[d$ z to exce$ enum]ation2 at a v mod]ate e/imate ,sir ,john ,h]s*el ?9ks ?is gr\p _c conta9 few] ?an a hundr$ ?\s& />s4 ,o!r two gr\ps betwe5 ! con/ellations ( ! ,%ield & ,ophiu*us /& out l promontories ( int5se brilliancy 9 ! d>k space t sep>ates ! />ry /reams ( ! ,milky ,way4 ,! di/ance ( ! fix$ />s is too great to admit ( _! exhibit+ a s5sible disc1 b !y mu/ be sph]ical if gravitation p]vades all space1 z !re is e reason to believe x does4 ,) a p[]ful telescope ! />s are l po9ts ( light3 _! occultations by ! moon are !re=e in/antane\s4 ,_! tw9kl+ arises f sudd5 *anges 9 ! refractive p[] ( ! air1 :i* w\ld n be s5sible if !y _h discs l planets4 ,?us no?+ c be kn[n ( _! di/ance f u or f "o ano!r by _! app>5t diamet]s4 ,al?\gh f ! appe>ance ( ! />s no inf]5ce c be drawn z to _! di/ance1 yet among ! multitudes 9 ! heav5s a few are f\nd ne> en\gh to exhibit di/9ct p>allactic motions aris+ f ! revolution ( ! e>? 9 its orbit1 f :5ce _! di/ance f ! sun has be5 comput$3 ,c5tauri1 ! brighte/ /> 9 ! s\!rn hemisph]e1 is a v rem>kable in/ance4 ,pr(essor ,h5d]son at ! ,cape ( ,good ,hope det]m9$ its p>allax to be #a by a s]ies ( obs]vations on its position at opposite p]iods ( ! ye>1 t is1 f opposite po9ts 9 ! e>?'s orbit4 ,! result 0 aft]w>ds confirm$ by ,mr4 ,macle>1 :o f\nd ! am\nt to be #jiac4 ,! diff]5ce betwe5 ! two is wond]fully small1 consid]+ ! _m unavoidable s\rces ( error 9 ! det]m9ation ( su* m9ute quantities 7,n4 #bcj74 ,s9ce no /> 9 ! nor!rn hemisph]e has s great an am\nt ( p>allax1 an arc ( #a is assum$ z ! p>allactic unit4 ,n[ radius is to ! s9e ( #a z #bjf1bfe is to #a2 h5ce1 ,c5tauri is #bjf1bfe times m di/ant f ! sun ?an ! sun is f ! e>?4 ,light fly+ at ! rate ( #aib1jjj miles 9 a second mu/ take #c ye>s & #hc days to come to u f t />4 ,"o or two t5?s ( a second becomes a v great error :5 ! maximum am\nt ( p>allax is only #a1 & on t acc\nt1 ) ! exception ( ,c5tauri1 x has be5 f\nd impracticable to det]m9e ! annual *anges 9 ! app>5t motions ( s+le />s affect$ by precession1 nutation1 ab]ration1 & ! v>iations ( temp]ature ( ! in/rum5ts us$ 9 obs]v+4 ,h[ev]1 z two />s 9 juxtaposition are equally affect$ by all ( ^!2 ! diff]5ce 9 _! motions is indep5d5t ( !m4 ,( two />s app>5tly 9 close approximation1 "o may be f> beh9d ! o!r 9 space4 ,!y may seem ne> to "o ano!r :5 view$ f ! e>? 9 "o "p ( its orbit1 b may sep>ate widely :5 se5 f ! e>? 9 ano!r position1 j z two t]re/rial objects appe> to be "o :5 view$ 9 ! same /raight l9e1 b sep>ate z ! obs]v] *anges 8 position4 ,9 ?is case ! />s w\ld n h real1 b only app>5t motion4 ,"o ( !m w\ld seem to oscillate annually to & fro 9 a /raight l9e on ea* side ( ! o!r1 a motion t c\ld n be mi/ak5 = t ( a b9>y sy/em :]e "o /> describes an ellipse ab\t ! o!r2 or if ! edge ( ! orbit be turn$ t[>ds ! e>?1 :]e ! oscillations require ye>s = _! accompli%m5t4 ,! only circum/ances t c affect ! />s unequally1 & :i* mu/ be elim9at$1 are ! prop] motion ( ! />s 9 space1 & specific ab]ration1 a v m9ute quantity aris+ f peculi>ities 9 ! />'s light4 ,?is me?od ( f9d+ ! di/ances ( ! fix$ />s 0 propos$ by ,galileo & attempt$ by ,dr4 ,long )\t success4 ,sir ,william ,h]s*el aft]w>ds appli$ x to "s ( ! b9>y gr\ps2 & al?\gh he did n f9d ! ?+ he s\ght =1 x l$ to ! discov]y ( ! orbital motions ( ! d\ble />s4 ,m4 ,/ruve 0 ! fir/ to apply ?is me?od1 & t 9 a v difficult case4 ,he p]ceiv$ t a v small /> is close to ,lyr1 & by a s]ies ( mo/ accurate diff]5tial measurem5ts f #ahce to #ahch he f\nd t ,lyr has a p>allax ( #jbfa1 :i* 0 aft]w>ds corroborat$ by ! obs]vations ( ,m4 ,pet]s2 h5ce ,lyr is #ghi1fjj times m di/ant f ! sun ?an ! e>? is4 ,x 0 natural to suppose t 9 g5]al ! l>ge />s are ne>] to ! e>? ?an ! small ones2 b !re is n[ reason to believe t "s />s1 ?\gh by no means brilliant1 are ne>] to u ?an o!rs :i* %9e ) great] spl5d\r4 ,?is is inf]r$ f ! comp>ative velocity ( _! prop] motions2 all ! />s h a g5]al motion ( translation1 :i* t5ds ultimately to mix ^? ( ! diff]5t con/ellations2 b none t we "k ( moves s rapidly z #fa ,cygni1 & on t acc\nt x 0 reckon$ to be ne>] to u ?an any o!r1 = an object seems to move m quickly ! ne>] x is4 ,n[ ,m4 ,bessel saw t two m9ute & probably v remote />s are v ne> #fa ,cygni1 _! directions f t /> be+ at "r angles to "o ano!r2 s t1 dur+ ! revolution ( ! e>?1 "o ( ^! di/ances 0 a maximum & ! o!r a m9imum alt]nately e ?ree mon?s4 ,?is alt]nation1 al?\gh x indicat$ a p>allax or diff]5ce ( p>allaxes ( only #jcdh1 0 ma9ta9$ ) su* p]fect regul>ity e ?ree mon?s1 t x leaves n a d\bt ( its accuracy1 :i* 0 aft]w>ds confirm$ by ! obs]vations ( ,m4 ,pet]s at ,polkova4 ,x foll[s f t small p>allax t #fa ,cygni mu/ be #eib1gjj times f>!r f ! e>? ?an ! sun is--a di/ance t light w\ld n pass ov] 9 less ?an n9e ye>s & ?ree mon?s4 ,mr4 ,h5d]son f\nd ! p>allax ( ,sirius1 ! brighte/ ( all ! />s1 to be only #jbcj2 x is consequ5tly m di/ant ?an #fa ,cygni1 ?\gh ! latt] is b ( ! #f? magnitude4 ,m4 ,argel&] has calculat$ t ! app>5t magnitude ( ! />s dep5ds ^u _! di/ance4 ,suppos+ !m all to be ( ! same size1 ! smalle/ visible 9 ,sir ,william ,h]s*el's #bj feet reflect+ telescope1 namely ^? ( ! #ag? magnitude1 w\ld be #bbh times f>!r (f ?an ^? ( ! fir/ magnitude2 & ,m4 ,pet]s ( ,polkova f ! annual p>allax ( ?irty-five1 sev5 ( :i* are n[ v accurately det]m9$1 has asc]ta9$ ! di/ance ( ! ne>e/ ( !m to be su*1 t light fly+ at ! rate ( #ie millions ( miles 9 a second w\ld take #ae ye>s & a half to come f !m to ! e>?1 & t a /> ( ! #ag? magnitude might be ext+ui%$ = #ceda ye>s be=e we %\ld be aw>e ( x4 7,n4 #bca47 ,! great gulfs t sep>ate ! />s f ! sun1 & probably f "o ano!r1 no d\bt ma9ta9 ! /ability ( ! /ell> sy/em1 9 ! same mann] t 9 ! sol> sy/em ! di/ances ( ! planets f ! sun & ! satellites f _! prim>ies are s arrang$ z to pres]ve _! mutual di/urbances )9 due limits4 ,! />s suppos$ to be ne>e/ ! sun are probably 9 a great zone :i* crosses ! ,milky ,way betwe5 ,args & ,crucis4 ,x comprises ! bright />s ( ! con/ellations ,orion1 ,canis ,major1 ! ,s\!rn ,cross1 ,c5taur1 ,lupus1 & ,scorpio4 ,! axis ( ! zone is incl9$ at an angle ( #bj to ! m$ial l9e1 or circle1 pass+ ?r\gh ! c5tre ( ! ,milky ,way4 ,a v great numb] ( />s und]go p]iodical *anges ( lu/re1 v>y+ 9 "s cases f complete ext9ction to _! orig9al brilliancy1 /rongly sugge/+ ! idea t !y are tempor>ily obscur$1 & sometimes completely hid1 by opaque bodies revolv+ r\nd !m 9 regul> p]iodic times1 z ! planets d ab\t ! sun4 ,! /> ,mira1 or ,ceti1 :i* 0 fir/ notic$ to be p]iodical by ,fabricius1 9 #aeif1 appe>s ab\t twelve times 9 elev5 ye>s1 or 9 p]iods ( #cca;d #h;h #dm #afs2 x rema9s at its greate/ brightness ab\t a =tnight1 be+ !n on "s occasions equal to a l>ge /> ( ! second magnitude2 !n x decreases dur+ ab\t ?ree mon?s1 till x becomes completely invisible to ! nak$ eye1 9 :i* /ate x rema9s ab\t five mon?s2 aft] t x cont9ues increas+ dur+ ! rema9d] ( its p]iod4 ,su* is ! g5]al c\rse ( its *anges2 b x does n always return to ! same degree ( brightness1 nor increase & dim9i% by ! same gradations1 nei!r are ! successive int]vals ( its maxima equal4 ,f ! obs]vations & inve/igations ( ,m4 ,argel&]1 ! mean p]iod giv5 is subject to fluctuation1 embrac+ #hh su* p]iods1 & hav+ ! effect ( gradually l5g!n+ & %ort5+ alt]nately ^? int]vals to ! ext5t ( #be days "o way & ! o!r4 ,! irregul>ities 9 ! degree ( brightness atta9$ at ! maximum are probably also p]iodical4 ,= f\r ye>s previ\s to #afgf x did n appe> at all2 & on ,octob] #e1 #ahci1 x exce$$ ,ceti1 & equall$ ,aurig1 9 lu/re4 ,^! irregul>ities may be occasion$ by p]iodical p]turbations among opaque bodies revolv+ ab\t ! />4 ,algol1 or ,p]sei1 is ano!r v rem>kable in/ance ( a v>iable />4 ,x has ! size ( a /> ( ! second magnitude = two days & ?irte5 & a half h\rs1 & !n sudd5ly beg9s to dim9i% 9 spl5d\r1 till1 9 ab\t ?ree h\rs & a half1 x is r$uc$ to ! size ( a /> ( ! f\r? magnitude2 x !n beg9s aga9 to increase1 & 9 ?ree h\rs & a half m rega9s its brightness1 go+ ?r\gh all ^! vicissitudes 9 #b;d #bj;h #dhm #eds#g4 ,sir ,john ,h]s*el & ,mr4 ,goodricke1 by :om ! v>iable nature ( ?is /> 0 discov]$ 9 #aghb1 consid]$ ?is to be a case /rongly indicative ( ! revolution ( an opaque body1 :i*1 com+ betwe5 u & ,algol1 cuts (f a l>ge portion ( ! light4 ,?is /> has be5 con/antly obs]v$1 & ! m rec5t obs]vations1 comp>$ ) ! anci5t ones1 indicat$ a dim9ution 9 ! p]iodic "t4 ,x is ev5 prov$ t ?is decrease is n uni=mly progressive1 b is actually proce$+ ) accel]at$ rapidity1 :i*1 h[ev]1 w probably n cont9ue1 b w by degrees relax1 & !n be *ang$ into increase1 accord+ to ! laws ( p]iodicity1 :i*1 z well z _! causes1 rema9 to be discov]$4 ,! fir/ m9imum ( ?is />1 9 #ahdd1 happ5$ on ,janu>y #crd1 at #d;h #adm ,gre5wi* "t4 ,hydr also vani%es & reappe>s e #did days4 ,lyr 0 discov]$ to be v>iable1 9 #aghd1 by ,mr4 ,goodricke1 & its p]iod 0 asc]ta9$ by ,argel&] to be #ab;d #ba;h #ecm #ajs1 9 :i* "t a d\ble maximum & m9imum takes place1 ! two maxima be+ ne>ly equal1 b ! two m9ima unequal2 besides ^! semi-p]iods1 !re is a sl[ ab]ration ( p]iod1 :i* appe>s to be p]iodical itself3 f its discov]y to #ahdj ! "t 0 cont9ually l5g!n+1 b m & m sl[ly1 till1 9 #ahdj1 x ceas$ to increase1 & has s9ce be5 sl[ly on ! decrease4 ,! />s ,cephei & ,aquil1 or ,ant9oi1 7 discov]$ to be v>iable 9 #aghd2 _! respective p]iods1 be+ #e;d #h;h #dgm #cis & #g;d #d;h #acm #ecs1 h s9ce be5 accurately det]m9$4 ,besides ^!1 ! v>iations ( betwe5 #cj & #dj h be5 approximately asc]ta9$1 & a great _m m among ! small] />s h be5 discov]$ to be v>iable by ,mr4 ,h9d1 :o has rem>k$ t _m ( ^? />s :i* cont9ue visible at _! m9imum appe> hazy & indi/9ct1 z ?\gh "s cl\dy or nebul\s m$ium int]v5$4 ,"s ( ! v>iable />s are r$1 & o!rs pres5t successive *anges ?r\gh blue1 yell[1 & r$4 ,:5 ! brightness is increas+ ! /> has a bluei% t+e1 :5 x is pa/ its maximum lu/re x assumes a yell[ t9t1 & :ile on its decrease x becomes ruddy ) fla%es ( bright r$ light4 ,^! *anges are v m>k$ 9 a small /> ne> ! /> #gg1 at ! extremity ( ! s\? w+ ( ,virgo4 ,sir ,john ,h]s*el1 aft] hav+ describ$ ! glory ( ! />ry heav5s1 asks1 8,= :at purpose are we to suppose su* magnific5t bodies scatt]$ ?r\gh ! abyss ( space8 ,surely n to illum9ate our nights1 :i* an additional moon ( ! ?\s&? "p ! size ( our own w\ld d mu* bett]1 nor to sp>kle z a pageant void ( mean+ & reality1 & bewild] u ) va9 conjectures4 ,useful1 x is true1 !y are to man z po9ts ( exact & p]man5t ref]5ce2 b he mu/ h /udi$ a/ronomy to little purpose :o c suppose man to be ! only object ( 8 ,creator's c>e1 or :o does n see 9 ! va/ & wond]ful app>atus ar\nd u provision = o!r races ( animat$ be+s4 ,! planets1 we h se51 d]ive _! light f ! sun1 b t _c be ! case ) ! />s4 ,^! d\btless !n are !mselves suns1 & may p]haps1 ea* 9 its sph]e1 be ! presid+ c5tre r\nd :i* o!r planets or bodies1 ( :i* we c =m no conception f any analogy (f]$ by our own sy/em1 may be circulat+40 ,ano!r circum/ance %[s h[ probable x is t d>k bodies are revolv+ among ! />s4 ,! prop] motion ( ,sirius is v irregul>--sometimes x is rapid1 & at o!r times sl[2 ! cause is ascrib$ by ,,mm4 ,bessel & ,pet]s to a d>k companion :i* revolves ) ,sirius ab\t _! common c5tre ( gravity1 & by its attraction di/urbs ! equable motion ( ! />4 ,sometimes />s h all at once appe>$1 %one ) a bright light1 & vani%$4 ,sev]al in/ances ( ^! tempor>y />s are on record4 ,a rem>kable "o occurr$ 9 ! ye> #abe1 :i* is said to h induc$ ,hipp>*us to =m ! fir/ catalogue ( />s4 ,ano!r /> appe>$ sudd5ly ne> ,aquil 9 ! ye> #chi1 :i* vani%$ aft] rema9+ = ?ree weeks z bright z ,v5us4 ,on ! #aj? ( ,octob]1 #afjd1 a brilliant /> bur/ =? 9 ! con/ellation ( ,s]p5t>ius1 :i* cont9u$ visible = a ye>2 & on ! #aa? ( ,novemb]1 #aegb1 a /> all at once %one =? 9 ,cassiopeia1 :i* rapidly increas$ 9 brightness till x surpass$ t ( ,jupit] s mu* z to be visible at midday4 ,x began to decrease 9 ,decemb] ( ! same ye>1 &1 9 ,m>*1 #aegd1 x _h entirely disappe>$1 hav+ exhibit$ a v>iety ( t9ts4 ,x is suspect$1 h[ev]1 t ?is /> is p]iodically v>iable & id5tical ) />s :i* appe>$ 9 ! ye>s #ide & #abfd4 ,a m rec5t case occurr$ 9 ! ye> #afgj1 :5 a new /> 0 discov]$ 9 ! head ( ! ,swan1 :i*1 aft] becom+ invisible1 reappe>$1 &1 hav+ und]gone _m v>iations 9 light1 vani%$ aft] two ye>s1 & has nev] s9ce be5 se54 ,on ! #bh? ( ,april1 #ahdh1 ,mr4 ,h9d discov]$ a /> ( ! #e? magnitude 9 ! con/ellation ,ophiu*us1 :i* 0 v conspicu\s to ! nak$ eye1 & :]e he 0 c]ta9 no /> ev5 s bright z ! #i? magnitude _h ev] exi/$1 nor 0 !re any record ( su* a />4 ,f ! "t ( its discov]y x cont9u$ to dim9i% till x became ext9ct4 ,its col\r 0 ruddy1 & 0 ?\ght to und]go rem>kable *anges1 probably an effect ( its l[ position1 z its pol> di/ance 0 #ajb #ci #ad4 ,sir ,john ,h]s*el discov]$ v s+ul> v>iations 9 ! /> ( ! con/ellation ,argo4 ,x is surr\nd$ by a wond]ful nebula1 & betwe5 ! ye>s #afgg & #ahbf x v>i$ twice f ! #d? to ! #bnd magnitude2 b 9 ! beg9n+ ( #ahch x sudd5ly increas$ 9 lu/re1 s z to be ne>ly z bright z ,c5tauri4 ,!nce x dim9i%$1 b n bel[ ! fir/ magnitude till ,april #ahdc1 :5 x _h aga9 increas$1 s z to surpass ,canopus1 & ne>ly equal ,sirius 9 spl5d\r4 ,) reg>d to ?is s+ul> ph5om5on1 ,sir ,john ,h]s*el obs]ves1 t 8,tempor>y />s h]et(ore record$ h all become totally ext9ct4 ,v>iable />s1 z f> z !y h be5 c>efully att5d$ to1 h exhibit$ p]iodical & regul> alt]nations 79 "s degree at lea/7 ( spl5d\r & comp>ative obscurity2 b "h we h a /> fitfully v>iable to an a/oni%+ ext5t1 & ^: fluctuations are spread ov] c5turies1 app>5tly 9 no settl$ p]iod1 & 9 no regul> progression4 ,:at orig9 c we ascribe to ^! sudd5 fla%es & relapses8 ,:at conclusions are we to draw z to ! com=t or habitability ( a sy/em dep5d+ = its supply ( light & heat on s v>iable a s\rce8 ,its future c>e] w be a subject ( high physical int]e/4 ,to ?is acc\nt ,i w only add1 t 9 ! beg9n+ ( #ahch ! brightness ( ?is /> 0 s great z mat]ially to int]f]e ) ! obs]vations ( t "p ( ! nebula surr\nd+ x40 ,sir ,john has also discov]$ t ,orionis is v>iable1 a circum/ance ! m rem>kable z x is "o ( ! conspicu\s />s ( our hemisph]e1 & yet its *anges _h nev] be5 rem>k$4 ,! inf]5ces ,sir ,john draws f ! ph5om5a ( v>iable />s are too int]e/+ n to be giv5 9 8 own words4 8,a p]iodic *ange exi/+ to s great an ext5t 9 s l>ge & brilliant a /> z ,orionis _c fail to awak5 att5tion to ! subject1 & to revive ! consid]ation ( ^? speculations respect+ ! possibility ( a *ange 9 ! lu/re ( our sun itself1 :i* 7 fir/ put =? by my fa!r4 ,if !re be really a community ( nature betwe5 ! sun & ! fix$ />s1 e pro( t we obta9 ( ! ext5sive preval5ce ( su* p]iodical *anges 9 ^? remote bodies adds to ! probability ( f9d+ some?+ ( ! k9d ne>] home4 ,if our sun 7 ev] intr9sically mu* bright] ?an at pres5t1 ! mean temp]ature ( ! surface ( our globe w\ld ( c\rse be proportionally great]4 ,i speak n[ n ( p]iodical1 b secul> *anges4 ,b ! argum5t is complicat$ ) ! consid]ation ( ! possible imp]fect transp>5cy ( space1 :i* may be due to mat]ial non-lum9\s p>ticles1 diffus$ irregul>ly 9 pat*es analog\s to nebul1 b ( great ext5t--to cosmical cl\ds1 9 %ort1 ( ^: exi/5ce we h1 ,i ?9k1 "s indication 9 ! s+ul> & app>5tly caprici\s ph5om5a ( tempor>y />s1 & p]haps 9 ! rec5t extraord9>y increase1 & h>dly less sudd5 dim9ution1 ( ,args40 ,mr4 ,h9d has come to ! same conclusion ) ,goodricke & ,sir ,john ,h]s*el1 t ! *anges 9 ! v>iable />s are ow+ to opaque bodies revolv+ r\nd !m2 inde$ !re are /rong reasons to believe t !re are sol> sy/ems analog\s to our own 9 ! remote regions ( space4 ,our sun requires n9e times ! p]iod ( ,algol to p]=m a revolution on its axis1 :ile1 on ! o!r h&1 ! p]iodic "t ( an opaque revolv+ body1 suffici5tly l>ge to produce a simil> tempor>y obscuration ( ! sun se5 f a fix$ />1 w\ld be less ?an f\rte5 h\rs4 ,x is possible t ! decrease ( light 9 "s ( ! v>iable />s may arise f l>ge spots on _! surface1 l ^? occasionally se5 9 ! radiant fluid masses on ! surface ( ! sun4 ,"o ( ^! spots :i* 0 measur$ by ,sir ,john ,h]s*el on ! #bj? ( ,m>*1 #ahcf1 ) its p5umbra1 occupi$ an area ( #cghj millions ( squ>e miles2 & ! black c5tral "p ( a spot t appe>$ on ! #be? ( ,may foll[+ w\ld h all[$ ! globe ( ! e>? to drop ?r\gh x1 leav+ a ?\s& miles cle> ( contact all ar\nd ?is trem5d\s abyss4 ,all ! v>iable />s on record ( :i* ! places are di/9ctly indicat$ h occurr$ )\t exception 91 or close ^u1 ! bord]s ( ! ,milky ,way1 & t only )9 ! foll[+ semicircle1 ! prec$+ hav+ (f]$ no example ( ! k9d4 ,_m />s h actually disappe>$ f ! heav5s4 #db ,virg9is seems to be ( ! numb]1 hav+ be5 miss$ by ,sir ,john ,h]s*el on ! #i? ( ,may1 #ahbh1 & n aga9 f\nd1 ?\gh he frequ5tly _h occasion to obs]ve t "p ( ! sky4 ,mr4 ,coop]1 ( ! ,m>kree ,obs]vatory1 has giv5 a li/ ( fifty />s t are miss+ s9ce ! publication ( 8 li/ ( />s 9 #ahdg4 ,comp>+ ! pres5t /ate ( ! heav5s ) m anci5t catalogues1 a mu* great] numb] h disappe>$4 ,?\s&s ( />s t seem to be only brilliant po9ts ( light1 :5 c>efully exam9$ are f\nd to be 9 reality sy/ems ( two or m suns1 _m ( :i* are kn[n to revolve ab\t "o ano!r4 ,^! b9>y & multiple sy/ems are v remote1 requir+ p[]ful telescopes to %[ ! />s sep>ately4 ,!y are divid$ into eight classes1 accord+ to ! proximity ( ! two />s4 ,! fir/ class comprises only su* z are less ?an #a ( space ap>t2 ^? ( ! second class are m ap>t ?an #a & less ?an #b1 c4 c4 ,sometimes ! two />s are ( equal magnitude1 b m frequ5tly a conspicu\s /> is accompani$ by a small] companion4 ,9 "s cases ! conspicu\s /> itself is d\ble1 z 9 ,cancri1 ,scorpio1 #aa ,monoc]otis1 & #ab ,lyncis1 :i* are triple />s4 ,ea* ( ! two />s ( ,lyr is a beautiful & close d\ble />2 s t :i* 9 a common telescope appe>s m]ely to be a d\ble />1 is f\nd to be quadruple ) a v excell5t in/rum5t4 ,! multiple sy/em ( ,orionis is "o ( ! mo/ rem>kable objects 9 our hemisph]e4 ,to ! nak$ eye & ) an ord9>y telescope x seems to be a s+le />1 b x really consi/s ( f\r brilliant />s =m+ a trapezium1 & accompani$ by two excessively m9ute & v close companions1 to p]ceive bo? ( :i* is ! sev]e/ te/ ( a telescope4 ,! fir/ catalogue ( d\ble />s 9 :i* _! places & relative positions are giv5 0 accompli%$ by ! tal5t & indu/ry ( ,sir ,william ,h]s*el1 :o made s _m great discov]ies1 & ) :om ! idea ( _! comb9ation 9 b9>y & multiple sy/ems orig9at$2 & t important fact he e/abli%$ by ! discov]y ( a revolv+ motion 9 #ej or #fj1 & by ! det]m9ation ( ! revolution ( "o /> ab\t ! o!r ( ,ca/or or ,gem9orum1 ! l>ge/ & f9e/ d\ble /> 9 ! nor!rn hemisph]e4 ,he ev5 assign$ ! approximate p]iodic times ( ?is & ( sev]al o!r b9>y sy/ems4 ,m ?an #ajj />s are n[ kn[n to be /ell> sy/ems4 ,! positions ( _m hundr$s 7 measur$ by ,sir ,john ,h]s*el & ,sir ,james ,s\?2 & ! catalogue ( ! d\ble />s 9 ! nor!rn hemisph]e1 :i* h be5 micrometrically measur$1 has be5 increas$ to m ?an #fjjj by ,,mm4 ,bessel1 ,/ruve1 & ,briti% a/ronom]s4 ,ext5sive catalogues ( d\ble />s 9 ! s\!rn hemisph]e h be5 publi%$ by ! a/ronom]s 9 our colonial e/abli%m5ts4 ,to ^! ,sir ,john ,h]s*el add$ #ajha dur+ 8 resid5ce at ! ,cape ( ,good ,hope3 ! angles ( position & di/ances ( ! />s f "o ano!r he measur$1 & f\nd t _m ( !m h v rapid orbital motions4 ,! elliptical elem5ts ( ! orbits & p]iodic times ( fifte5 h be5 det]m9$ by ! mo/ em95t a/ronom]s ) wond]ful accuracy1 consid]+ ! enorm\s di/ances & ! extreme delicacy & difficulty ( ! subject4 ,m4 ,sav>y has ! m]it ( hav+ fir/ det]m9$ ! elem5ts ( ! orbit ( a d\ble /> f obs]vation4 ,! difficulty ( do+ s is great1 because ! ne>e/ fix$ /> is #baa1jjj times f>!r f ! sun ?an ! e>? is1 & ! orbit itself is only visible ) ! be/ telescopes2 consequ5tly a v small error 9 obs]vation occasions an enorm\s error 9 ! det]m9ation ( quantities at t di/ance4 ,9 obs]v+ ! relative position ( ! />s ( a b9>y sy/em1 ! di/ance betwe5 !m1 & also ! angle ( position1 t is1 ! angle :i* ! m]idian1 or a p>allel to ! equator1 makes ) ! l9e jo9+ ! two />s1 are measur$4 ,! diff]5t values ( ! angle ( position %[ :e!r ! revolv+ /> moves f ea/ to we/1 or ! contr>y2 :e!r ! motion be uni=m or v>iable1 & at :at po9ts x is greate/ or lea/4 ,! measures ( ! di/ances %[ :e!r ! two />s approa* or rec$e f "o ano!r4 ,f ^! ! =m & nature ( ! orbit are det]m9$4 ,7 obs]vations p]fectly accurate1 f\r values ( ! angle ( position1 & ( ! correspond+ di/ances at giv5 epo*s1 w\ld be suffici5t to assign ! =m & position ( ! curve describ$ by ! revolv+ />2 ?is1 h[ev]1 sc>cely ev] happ5s4 ,! accuracy ( ea* result dep5ds ^u tak+ ! mean ( a great numb] ( ! be/ obs]vations1 & elim9at+ error by mutual comp>ison4 ,! di/ances betwe5 ! />s are s m9ute t !y _c be measur$ ) ! same accuracy z ! angles ( position2 !re=e1 9 ord] to det]m9e ! orbit ( a /> indep5d5tly ( ! di/ance1 x is necess>y to assume1 z ! mo/ probable hypo!sis1 t ! />s are subject to ! law ( gravitation1 & consequ5tly t "o ( ! two />s revolves 9 an ellipse ab\t ! o!r1 suppos$ to be at re/1 ?\gh n necess>ily 9 ! focus4 ,a curve is ?us con/ruct$ graphically by means ( ! angles ( position & ! correspond+ times ( obs]vation4 ,! angul> velocities ( ! />s are obta9$ by draw+ tang5ts to ?is curve at /at$ int]vals1 :5ce ! app>5t di/ances1 or radii vectores ( ! revolv+ />1 become kn[n = ea* angle ( position1 because1 by ! laws ( elliptical motion1 !y are equal to ! squ>e roots ( ! app>5t angul> velocities4 ,n[ t ! angles ( position e/imat$ f a giv5 l9e1 & ! correspond+ di/ances ( ! two />s1 are kn[n1 ano!r curve may be drawn1 :i* w repres5t on pap] ! actual orbit ( ! /> project$ on ! visible surface ( ! heav5s2 s t ! elliptical elem5ts ( ! true orbit1 & its position 9 space1 may be det]m9$ by a comb9$ sy/em ( measurem5ts & computation4 ,b1 z ?is orbit has be5 obta9$ on ! hypo!sis t gravitation prevails 9 ^! di/ant regions1 :i* c\ld n be kn[n priori1 x mu/ be comp>$ ) z _m obs]vations z c be obta9$1 to asc]ta9 h[ f> ! comput$ ellipse agrees ) ! curve actually describ$ by ! />4 ,virg9is consi/s ( two />s ( ne>ly ! same magnitude2 !y 7 s f> ap>t 9 ! beg9n+ & middle ( la/ c5tury1 t !y 7 m5tion$ by ,bradley1 & m>k$ 9 ,may]'s catalogue1 z two di/9ct />s4 ,s9ce t "t !y h be5 cont9ually approa*+ ea* o!r1 till 9 ,janu>y1 #ahcf1 "o /> 0 se5 to eclipse ! o!r1 by ,admiral ,smy? at 8 ,obs]vatory at ,b$=d1 & by ,sir ,john ,h]s*el at ! ,cape ( ,good ,hope4 ,a s]ies ( obs]vations s9ce ! beg9n+ ( ! pres5t c5tury has enabl$ ,sir ,john to det]m9e ! =m & position ( ! elliptical orbit ( ! revolv+ /> ) extraord9>y tru? by ! prec$+ me?od4 ,accord+ to 8 calculation1 x came to its p]ihelion on ! #ah? ( ,augu/ ( ! ye> #ahcd4 ,its previ\s velocity 0 s great t ! revolv+ /> describ$ an angle ( #fh 9 "o ye>4 ,by ! laws ( elliptical motion its angul> velocity mu/ dim9i% till x arrives at its aphelion4 ,! accuracy ) :i* ! motions ( ! b9>y sy/ems are measur$1 & ! skill employ$ 9 ! d$uction ( ! elliptical elem5ts1 are n[ s great1 t ! p]iodic "t ( ,virg9is1 det]m9$ by ,sir ,john ,h]s*el & ,admiral ,smy? f _! respective obs]vatories1 comb9$ ) ^? ( ,sir ,william ,h]s*el1 only diff] by two ye>s1 ,sir ,john hav+ obta9$ a p]iod ( #ahb ye>s1 ,admiral ,smy? t ( #ahj4 ,by ! aid ( m num]\s obs]vations ,mr4 ,flet*] has f\nd t ! true p]iod is #ahdec ye>s1 & t ! revolv+ /> pass$ its p]ihelion 9 #ahcg4 ,x is by su* successive /eps t a/ronomy is br\ght to p]fection 7,n4 #bcb74 ,"s ( ! d\ble />s h v long p]iods1 su* z ,coron1 :]e ! revolv+ /> takes #gcg ye>s ne>ly to accompli% a circuit4 ,o!rs aga9 h v %ort p]iods1 z ,coron1 ,cancri1 & ,urs ,majoris1 ^: p]iodic times are #dbejj1 #ehia1 & #ehbf ye>s respectively3 !re=e ea* ( ^! has p]=m$ m ?an "o entire revolution s9ce _! motions 7 obs]v$4 ,h]culis1 ^: p]iodic "t is only ab\t #cj-a_/d ye>s1 has accompli%$ two complete circuits1 ! less] /> hav+ be5 eclips$ by ! great] ea* "t4 ,! fir/ ( ^! two truly wond]ful ev5ts1 ( "o sun eclips+ ano!r sun1 0 se5 by ,sir ,william ,h]s*el 9 #aghb4 ,! orbits & p]iodic times ( s _m ( ^! b9>y sy/ems hav+ be5 det]m9$ proves beyond a d\bt t sun revolves ab\t sun 9 ! />ry firmam5t by ! same law ( gravitation t makes ! e>? & planets revolve ab\t ! sun 7,n4 #bcb74 ,s9ce ! p>allax ( #fa ,cygni & t ( ,c5tauri h be5 det]m9$1 ,sir ,john ,h]s*el has made ! foll[+ approximation to ! dim5sions ( _! orbits & masses4 ,! di/ance betwe5 ! two />s ( #fa ,cygni1 t is ! radius vector ( ! revolv+ />1 has h>dly v>i$ f #aee ev] s9ce ! e>lie/ obs]vations2 :ile 9 t "t ! /> has mov$ ?r\gh #ej2 x is evid5t !re=e t ! orbit mu/ be ne>ly circul>4 ,x is at "r angles to ! visual ray1 & ! p]iodic "t is #ead ye>s4 ,! p>allax or radius ( ! e>?'s orbit z se5 f ! /> is #jcdh1 :ile ! radius ( ! />'s orbit z se5 f ! e>? is #aee2 h5ce ! radius ( ! />'s orbit is to t ( ! e>?'s orbit z #aee to #jcdh1 or ne>ly z #de to #a4 ,s ! orbit describ$ by ! two />s ( #fa ,cygni ab\t "o ano!r greatly exce$s t :i* ,neptune describes ab\t ! sun4 ,s9ce ! mean di/ance ( ! />s & _! p]iodic "t are giv51 ! sum ( ! masses ( ! two />s is comput$ to be #jcebi1 t ( ! sun be+ #a4 ,?us our sun is n va/ly great] nor va/ly less ?an ! />s compos+ #fa ,cygni1 :i* is a small inconspicu\s /> to ! nak$ eye1 n exce$+ ! #f? magnitude4 ,( all ! d\ble />s ,c5tauri is ! mo/ beautiful3 x is ! brighte/ /> 9 ! s\!rn hemisph]e1 equal1 if n sup]ior1 to ,arcturus 9 lu/re4 ,! di/ance betwe5 ! two />s has be5 decreas+ at ! rate ( half a second annually s9ce ! ye> #ahbb1 :ile ! angul> motion has und]gone v little *ange1 :i* %[s t ! plane ( ! orbit passes ?r\gh ! e>? l ! orbits ( #dd ,botes1 & ,s]p5t>ii2 t is to say1 ! edge ( ! orbit 9 ^! ?ree /ell> sy/ems is pres5t$ to ! e>?1 s t ! revolv+ /> seems to move 9 a /raight l9e1 & to oscillate on ea* side ( its prim>y4 ,7 ?is libration ow+ to p>allax1 x w\ld be annual f ! revolution ( ! e>? ab\t ! sun2 b z ye>s elapse be=e x am\nts to a s5sible quantity1 x c only arise f a real orbital motion se5 obliquely4 ,9 ?is case five obs]vations are suffici5t = ! det]m9ation ( ! orbit1 provid$ !y be exact2 b ! quantities to be measur$ are s m9ute1 t x is only by a v long s]ies ( obs]vations t accuracy c be atta9$4 ,9 #ahcd ,capta9 ,jacob det]m9$ ! p]iodic "t ( ! revolv+ /> ( ,c5tauri to be #gg ye>s1 & ! di/ance betwe5 ! two to be #age2 & s9ce ! decrease is half a second annually1 ! di/ance or radius vector ( ! revolv+ /> 0 #abe 9 ! ye> #ahbb2 & z ,mr4 ,h5d]son _h det]m9$ ! p>allax or radius ( ! e>?'s orbit z se5 f ! /> to be #iac1 x foll[s t ! real semi-axis ( ! revolv+ />'s orbit is #ac-a_/b times great] ?an ! semi-axis ( ! e>?'s orbit z a m9imum4 ,! real dim5sions ( ! ellipse !re=e _c be s small z ! orbit ( ,saturn1 & may possibly exce$ t ( ,uranus4 ,x is v probable t an occultation ( "o ( ! suns by ! o!r w take place 9 #ahfg1 or a v close appulse ( ! two />s4 ,s+ul> anomalies h appe>$ 9 ! motions ( #gj ,ophiu*i1 :i* 0 discov]$ to be a b9>y sy/em by ,sir ,william ,h]s*el 9 #aggi1 & :i* has s9ce ne>ly accompli%$ a revolution4 ,v>i\s orbits h be5 comput$3 ^? :i* be/ repres5t ! angles ( position fail ) reg>d to ! di/ances ( ! />s f "o ano!r1 & vice v]s4 ,b x is a v rem>kable fact t ! errors are p]iodical1 be+ = consid]able p]iods ( "t alt]nately 9 excess & defect4 ,capta9 ,w4 ,s4 ,jacob1 :o det]m9$ ! p]iodic "t ( ! revolv+ /> to be #ic ye>s1 attributes ?is anomaly to ! di/urb+ action ( an opaque body revolv+ r\nd ! less] />4 ,assum+ t to be ! case1 & comput+1 he f\nd t ! errors 7 consid]ably dim9i%$ bo? 9 ! angle ( position & di/ance4 ,x is a subject ( ! highe/ int]e/1 & well wor?y ( ! att5tion ( su* a/ronom]s z h ! means ( mak+ ! necess>y obs]vations4 ,among ! triple sy/ems1 z ,cancri1 two ( ! />s revolve ab\t "o ano!r 9 #ehi ye>s2 b ! motion ( ! ?ird & mo/ di/ant is s sl[1 t x has only accompli%$ a t5? "p ( its revolution ab\t ! o!r two s9ce ! sy/em 0 discov]$4 ,x appe>s f ! calculations ( ,mr4 ,dunlop t ,eridani accompli%es a revolution 9 little m ?an #cj ye>s4 ,! motion ( ,m]cury is m rapid ?an t ( any ( ! planets1 be+ at ! rate ( #ajg1jjj miles an h\r4 ,! p]ihelion velocity ( ! comet ( #afhj 0 #hhj1jjj miles an h\r2 b1 if ! two />s ( ,eridani1 or ( ,urs ,majoris1 be z remote f "o ano!r z ! ne>e/ fix$ /> is f ! sun1 ! velocity ( ! revolv+ /> mu/ exce$ ! p[] ( imag9ation to conceive4 ,! elliptical motion ( ! d\ble />s %[s t gravitation is n conf9$ to ! planet>y motions1 b t sy/ems ( suns 9 ! f> di/ant regions ( ! univ]se are also ob$i5t to its laws4 ,! /ell> sy/ems pres5t a k9d ( sid]eal *ronomet]1 by :i* ! *ronology ( ! heav5s w be m>k$ out to future ages by epo*s ( _! own1 liable to no fluctuations f su* di/urbances z take place 9 our sy/em4 ,"s />s are app>5tly d\ble1 ?\gh altoge!r unconnect$1 "o be+ f> beh9d ! o!r 9 space1 z ,lyr1 :i* app>5tly consi/s ( two />s1 "o ( ! fir/1 ! o!r ( ! elev5? magnitude4 ,aldeb>an1 ,aquil1 & ,pollux are rem>kable in/ances ( ^! optically d\ble />s4 ,x has be5 %[n h[ fav\rable t circum/ance is = asc]ta9+ ! p>allax ( ! ne>e/ ( ! two4 7,n4 #bcb47 ,! d\ble />s are ( v>i\s hues3 sometimes bo? />s are ( ! same col\r1 z 9 ,c5tauri & #fa ,cygni1 :]e ! l>g] />s are ( a bright orange & ! small] ones a deep] t9t ( ! same1 b !y mo/ frequ5tly exhibit ! contra/$ col\rs4 ,! l>ge /> is g5]ally yell[1 orange1 or r$2 & ! small /> blue1 purple1 or gre54 ,sometimes a :ite /> is comb9$ ) a blue or a purple1 & m r>ely a r$ & :ite are unit$4 ,9 _m cases ^! appe>ances are due to ! influ5ce ( contra/ on our judgm5t ( col\rs4 ,= example1 9 obs]v+ a d\ble />1 :]e ! l>ge "o is a full ruby r$1 or almo/ blood col\r1 & ! small "o a f9e gre51 ! latt] loses its col\r :5 ! =m] is hid by ! cross wires ( ! telescope4 ,t is ! case ) ,&rom$1 :i* is a triple />1 ! small "o1 :i* appe>s gre51 be+ closely d\ble4 ,cancri is an in/ance ( a l>ge yell[ /> & a small "o :i* appe>s blue by contra/4 ,/ill !re are a va/ numb] :]e ! col\rs are decid$ly diff]5t1 & sugge/ ! curi\s idea ( two suns1 a r$ & a gre51 or a yell[ & a blue1 s t a planet circulat+ r\nd "o ( !m may h ! v>iety ( a r$ day & a gre5 day1 a yell[ day & a blue day4 ,sir ,john ,h]s*el obs]ves1 9 "o ( 8 pap]s 9 ! ,philosophical ,transactions1 z a v rem>kable fact1 t1 al?\gh r$ />s are common en\gh1 no example ( a solit>y blue1 gre51 or purple /> has yet be5 produc$4 ,sirius is ! only /> on record ^: col\r has *ang$4 ,9 ! "t ( ,ptolemy x 0 r$2 n[ x is "o ( ! :ite/ />s 9 ! heav5s4 ,m4 ,/ruve has f\nd t1 out ( #eif bright d\ble />s1 #cge pairs h ! same int5sity ( light & col\r2 #aja pairs h diff]5t int5sity1 b ! same col\r2 & #abj pairs h ! col\rs ( ! two />s decid$ly diff]5t4 ,c]ta9 rays1 :i* exi/ 9 ! sun's light1 are want+ 9 ! spectra ( e col\r$ />1 & probably nev] exi/$ 9 ! light ( ^! />s1 z !re is no reason to believe t !y are absorb$ by ! />s' atmosph]e1 ?\gh !y may be by ! e>?'s4 ,!re are no defective rays 9 ! :ite light ( ,sirius1 ,procyon1 & o!rs2 b ,sir ,david ,brew/] f\nd 9 ! spectrum ( ! orange-col\r$ light ( ,h]culis a defective b& 9 ! r$ space1 & two or m 9 ! blue2 consequ5tly1 ! orange col\r ( ! /> is ow+ to a want ( blue rays2 = flames 9 :i* c]ta9 rays are want+ take ! col\r ( ! pr$om9at+ rays4 ,if ! black rays 9 ! sol> spectrum 7 ow+ to ! absorption ( ! sun's atmosph]e1 ! light f ! m>g9 ( 8 disc1 hav+ to pass ?r\gh a great] ?ickness ( x1 w\ld exhibit deep] l9es ?an t :i* comes f 8 c5tre2 b1 z no diff]5ce is p]ceptible1 x may be inf]r$ t ! analog\s b&s 9 ! light ( ! col\r$ />s are n due to ! absorption ( _! atmosph]es1 b t !y arise f ! diff]5t k9ds ( combu/ion by :i* ^! bodies are light$ up4 ,all ! ord9>y me?ods fail = f9d+ ! p>allax :5 ! di/ances ( ! />s are v great4 ,an angle ev5 ( "o or two seconds1 view$ 9 ! focus ( our l>ge/ telescopes1 does n equal ! ?ickness ( a spid]'s ?read1 :i* makes x impossible to measure su* m9ute quantities ) any degree ( accuracy4 ,9 "s cases1 h[ev]1 ! b9>y sy/ems ( />s furni% a me?od ( e/imat+ an angle ( ev5 ! t5? ( a second1 :i* is ?irty times m accurate ?an by any o!r means4 ,f !m ! actual di/ances ( "s ( ! m remote />s w ultimately be kn[n4 ,suppose t "o /> revolves r\nd ano!r 9 an orbit :i* is s obliquely se5 f ! e>? z to look l an ellipse 9 a horizontal position1 !n x is cle> t "o-half ( ! orbit w be ne>] to u ?an ! o!r half4 ,n[1 9 consequ5ce ( ! "t :i* light takes to travel1 we always see ! satellite /> 9 a place :i* x has already left4 ,h5ce1 :5 t /> sets out f ! po9t ( its orbit :i* is ne>e/ to u1 its light w take m & m "t to come to u 9 proportion z ! /> moves r\nd to ! mo/ di/ant po9t 9 its orbit4 ,on t acc\nt ! /> w appe> to u to take m "t 9 mov+ ?r\gh t half ( its orbit ?an x really does4 ,exactly ! contr>y takes place on ! o!r half2 = ! light w take less & less "t to arrive at ! e>? 9 proportion z ! /> approa*es ne>] to u2 & !re=e x w seem to move ?r\gh ?is half ( its orbit 9 less "t ?an x really does4 ,?is circum/ance furni%es ! means ( f9d+ ! absolute bread? ( ! orbit 9 miles1 & f t ! true di/ance ( ! /> f ! e>?4 ,=1 s9ce ! greate/ & lea/ di/ances ( ! satellite /> f ! e>? diff] by ! bread? ( its orbit1 ! "t :i* ! /> takes to move f ! ne>e/ to ! remote/ po9t ( its orbit is great] ?an x ought to be by ! :ole "t its light takes to cross ! orbit1 & ! p]iod ( mov+ ?r\gh ! o!r half is exactly z mu* less4 ,h5ce ! diff]5ce betwe5 ! obs]v$ times ( ^! two semi-revolutions ( ! /> is equal to twice ! "t t its light employs to cross its orbit2 &1 z we "k ! velocity ( light1 ! diamet] ( ! orbit may be f\nd 9 miles1 & f t its :ole dim5sions2 = ! position ( ! orbit ) reg>d to u is kn[n by obs]vation1 z well z ! place1 incl9ation1 & app>5t magnitude ( its major axis1 or1 :i* is ! same ?+1 ! angle "u :i* x is se5 f ! e>?4 ,s9ce1 !n1 ?ree ?+s are kn[n 9 ?is great triangle1 namely1 ! base or major axis ( ! orbit 9 miles1 ! angle opposite to x at ! e>?1 & ! angle x makes ) ! visual ray1 ! di/ance ( ! satellite /> f ! e>? may be f\nd by ! mo/ simple ( calculations4 ,! m]it ( hav+ fir/ propos$ ?is v +5i\s me?od ( f9d+ ! di/ance ( ! />s is due to ,m4 ,sav>y2 b1 un=tunately1 x is n ( g5]al application1 z x dep5ds ^u ! position ( ! orbit1 & a long "t mu/ elapse be=e obs]vation c furni% data1 s9ce ! %orte/ p]iod ( any revolv+ /> t we "k ( is #cj ye>s4 ,/ill ! di/ances ( a va/ numb] ( />s may ultimately be made out 9 ?is way2 &1 z "o important discov]y almo/ always leads to ano!r1 _! masses may ?us be weigh$ aga9/ t ( ! e>? or sun4 ,! only data employ$ = f9d+ ! mass ( ! e>?1 z comp>$ ) t ( ! sun1 are1 ! angul> motion ( our globe r\nd ! sun 9 a second ( "t1 & ! di/ance ( ! e>? f ! sun 9 miles 7,n4 #bcc74 ,n[1 by obs]vations ( ! b9>y sy/ems1 we "k ! angul> velocity ( ! small /> r\nd ! great "o2 &1 :5 we "k ! di/ance betwe5 ! two />s 9 miles1 x w be easy to compute h[ _m miles ! small /> w\ld fall ?r\gh by ! attraction ( ! great "o 9 a second ( "t4 ,a comp>ison ( ?is space ) ! space ?r\gh :i* ! e>? w\ld desc5d t[>ds ! sun 9 a second w give ! ratio ( ! mass ( ! great /> to t ( ! sun or e>?4 ,accord+ to ,m4 ,bessel1 ! weight ( ! two />s ( #fa ,cygni is equal to half ! weight ( ! sun4 ,little z we "k ( ! absolute magnitude ( ! fix$ />s1 ! quantity ( light emitt$ by _m ( !m %[s t !y mu/ be mu* l>g] ?an ! sun4 ,dr4 ,wolla/on det]m9$ ! approximate ratio :i* ! light ( a wax c&le be>s to t ( ! sun1 moon1 & />s1 by comp>+ _! respective images reflect$ f small glass globes fill$ ) m]cury1 :5ce a comp>ison 0 e/abli%$ betwe5 ! quantities ( light emitt$ by ! cele/ial bodies !mselves4 ,by ?is me?od he f\nd t ! light ( ,lyr is five & a half times great] ?an t ( ! sun4 ,sir ,john ,h]s*el reflect$ ! moon's light totally by a prism1 :i*1 conc5trat$ by a l5s1 0 comp>$ directly ) t ( ,c5tauri4 ,aft] mak+ all[ance = ! quantity ( ! moon's light lo/ 9 pass+ ?r\gh ! l5s & prism1 he f\nd t ! mean quantity ( light s5t to ! e>? by a full moon exce$s t s5t by ,c5tauri 9 ! proportion ( #bg1djh to #a4 ,n[1 ,dr4 ,wolla/on f\nd ! proportion ( ! sun's light to t ( ! full moon to be t ( #hja1jgb to #a4 ,h5ce1 ! light s5t to u by ! sun is to t s5t by ,c5tauri z ab\t tw5ty-two ?\s& millions to "o4 ,b1 z ! p>allax ( ,c5tauri is #a1 x really is two & a half times bright] ?an ! sun4 ,! light ( ,sirius is f\r times t ( ,c5tauri1 b its p>allax is only #jbcj3 h5ce x has an intr9sic spl5d\r #fcjb times t ( our lum9>y4 ,x is !re=e e/imat$ to be a hundr$ times z l>ge2 s t1 7 ,sirius 9 ! e>?'s place1 its surface w\ld ext5d #aej times z f> z ! orbit ( ! moon4 ,! light ( ,sirius1 accord+ to ! obs]vations ( ,sir ,john ,h]s*el1 is #cbd times great] ?an t ( a /> ( ! six? magnitude2 if we suppose ! two to be really ( ! same size1 _! di/ances f u mu/ be 9 ! ratio ( #egc to #a1 because light dim9i%es z ! squ>e ( ! di/ance ( ! lum9\s body increases4 ,s _m ( ! />s h prop] motions altoge!r indep5d5t ( ! annual rotation ( ! e>? 9 its orbit1 t x may be d\bt$ :e!r !re be su* a ?+ z a fix$ />4 ,groombridge is ! mo/ rapid kn[n3 x has a prop] motion ( #g ( arc annually2 ,c5tauri moves at ! rate ( #ceh annually1 & #fa ,cygni describes a l9e 9 space ( #eab 9 ! same "t4 ,^! motions are probably 9 curves1 b at ! di/ance ( ! e>? !y w appe> to be rectil9eal = ages to come4 ,! motion ( little m ?an five seconds ( space1 :i* #fa ,cygni describes annually1 seems to u to be extremely small2 b at ! di/ance ( t /> an angle ( "o second corresponds to tw5ty-f\r millions ( millions ( miles2 consequ5tly ! annual motion ( #fa ,cygni is #abj millions ( millions ( miles1 & yet1 z ,m4 ,arago obs]ves1 we call x a fix$ />4 ,f ! same cause x is evid5t t ! cr[d+ ( ! />s 9 ! ,milky ,way may be app>5t only1 & t ! />s may be at va/ di/ances f "o ano!r1 & no d\bt are4 ,7 ! sol> sy/em & ! :ole ( ! />s visible to u c>ri$ =w>d 9 space by a motion common to all1 l %ips drift+ 9 a curr5t1 x w\ld be impossible = u1 mov+ ) ! re/1 to asc]ta9 its direction4 ,sir ,william ,h]s*el p]ceiv$ t a great "p ( ! motions ( ! />s is only app>5t1 aris+ f a real motion ( ! sun 9 a contr>y direction4 ,among _m discrepancies he f\nd t ! />s 9 ! nor!rn hemisph]e h a g5]al t5d5cy to move t[>ds a po9t diametrically opposite to ,h]culis1 :i* he attribut$ to a motion ( ! sol> sy/em 9 a contr>y direction4 ,= x 0 evid5t to him1 t ! />s1 f ! effects ( p]spective alone1 w\ld seem to div]ge 9 ! direction to :i* ! sol> sy/em 0 go+1 & w\ld conv]ge t[>ds ! space x _h left1 & t !re w\ld be a regul>ity 9 ^! app>5t motions :i* w\ld h]eaft] be detect$4 ,s9ce ,sir ,william ,h]s*el's "t ! prop] motions ( ! />s h be5 det]m9$ ) mu* great] accuracy1 & _m h be5 add$ to ! li/ by comp>+ ! anci5t & mod]n tables ( _! places2 8 views h be5 e/abli%$ by f\r ( ! greate/ a/ronom]s ( ! age1 ,,mm4 ,lundahles1 ,argel&]1 ,otto ,/ruve1 & ,pet]s1 :o h cle>ly prov$ ! motion ( ! sun f t ( ! />s 9 ! nor!rn hemisph]e1 & ,mr4 ,gall[ay has come to ! same conclusion f ! motions ( ! />s 9 ! s\!rn hemisph]e 7,n4 #bcd74 ,! result is1 t ! sun1 accompani$ by all 8 att5dant planets1 is mov+ at ! rate ( #dbb1dbd miles--or ov] a space ne>ly equal to 8 own diamet]--9 ! c\rse ( a day1 & t ! motion is direct$ t[>ds a po9t 9 a l9e jo9+ ! two />s & ,h]culis at a qu>t] ( ! app>5t di/ance ( ^! two />s1 reckon+ f ,h]culis4 ,?is inve/igation 0 f\nd$ ^u no law assum$ or obs]v$1 su* z ! circulation ( all ! />s ( our firmam5t ab\t a common c5tre1 ?\gh philosoph]s h speculat$ z to ! probability ( su* a motion 9 ! sun & />s 9 ! plane ( ! ,milky ,way4 ,%\ld ! sun & 8 /ell> companions be mov+ 9 a ne>ly circul> orbit1 ! c5tre ( motion w\ld be 9 ! plane pass+ ?r\gh ! sun p]p5dicul> to ! direction ( 8 motion4 ,! con/ellations ?r\gh :i* t great circle w\ld pass are ,pisces1 ,au/ralis1 ,pegasus1 ,&rom$a1 ,p]seus1 c4 ,m4 ,argel&] is ( op9ion t ! sun's orbit is ne>ly 9 ! plane ( ! ,milky ,way1 &1 !re=e1 t its c5tre mu/ probably be 9 ,p]seus1 :ile ,m4 ,mdl] places x 9 ! ,pleiades1 :i* seems to be inadmissible2 b ! data are too unc]ta9 at pres5t to admit ( any absolute conclusion z to ! sun's orbit & ! g5]al motion ( ! /ell> firmam5t3 = ?\gh ! />s 9 e region ( ! sky t5d t[>ds a po9t 9 ,h]cules1 x is n yet kn[n :e!r _! motions are uni=m or v>iable1 :e!r ! sun's motion be gradually *ang+1 & :e!r ! />s =m diff]5t indep5d5t sy/ems1 ea* hav+ its own c5tre ( attraction1 or if all obey "o p[]ful controll+ =ce :i* p]vades ! :ole univ]se4 ,accurate obs]vations ( ! places ( a select numb] ( />s ( all dim5sions 9 ! ,milky ,way cont9u$ = a s]ies ( ye>s w\ld no d\bt decide ?is po9t4 ,! prop] motion ( a /> comb9$ ) ! progressive velocity ( light alt]s ! app>5t p]iodic "t ( ! revolv+ /> ( a b9>y sy/em4 ,if ! orbit ( a d\ble /> be at "r angles to ! visual ray1 & bo? ! sun & ! /> at re/1 ! p]iodic "t ( ! revolv+ />1 say ( #aj1jjj days1 w\ld always be ! same4 ,b if ! c5tre ( gravity ( ! /> 7 to rec$e 9 a direct l9e f ! sun ) ! velocity ( "o t5? ( ! radius ( ! e>?'s orbit 9 a day1 !n at ! end ( #aj1jjj days x w\ld be m remote f u by #ajjj ( su* radii--a space light w\ld take #eg days to trav]se3 h5ce1 al?\gh ! p]iodic "t ( ! /> w\ld really be ! same1 ! completion ( its p]iod w\ld only be kn[n to u #eg days aft] x _h tak5 place1 s t ! p]iodic "t w\ld appe> to u to be #aj1jeg days in/ead ( #aj1jjj4 ,7 ! /> to approa* to ! sun by ! same quantity in/ead ( rec$+1 ! app>5t p]iodic "t w\ld be dim9i%$ by #eg days4 ,z ! sun is only a unit 9 ! /ell> sy/em1 s ! ,milky ,way1 & all ! />s t adorn ! firmam5t ( bo? hemisph]es1 con/itute a gr\p :i* is b a unit among ! inf9ite numb]s ( />ry clu/]s & nebul t are pr(usely scatt]$ ?r\gh\t ! univ]se4 ,by ! aid ( a good telescope !re may be se5 on ! cle> vault ( heav51 betwe5 ! />s ( our own /ell> sy/em1 & f> 9 ! dep?s ( space1 an imm5se multitude ( objects l comets or cl\ds ( :ite vap\r ( all =ms & sizes4 ,"s are mix$ ) />s1 o!rs are entirely =m$ ( !m4 ,_m appe> z if !y 7 /ell>1 b requir$ a telescope ( high] p[] to resolve !m1 & va/ numb]s appe> to be matt] r>efi$ 9 ! highe/ possible degree1 giv+ no indication ( a /ell> nature2 & ^! are 9 e /ate ( cond5sation1 f a vague film h>dly to be disc]n$ to su* z h actually arriv$ at a solid nucleus ( />s4 ,! cl\dy appe>ance is m]ely ! bl5d+ ( ! rays ( innum]able />s :i* are !mselves invisible f _! extreme di/ance1 l p>ts ( ! ,milky ,way4 ,sir ,william ,h]s*el 0 at fir/ ( t op9ion1 & ! nebul t h be5 resolv$ by ,"l ,rosse's telescope h l$ a/ronom]s to believe t su* is ! case4 ,yet ! tails ( comets1 ! zodiacal light1 & ! ext5sive lum9\s atmosph]es :i* encompass _m ( ! />s1 %[ t1 9 all probability1 a self-lum9\s phosphoresc5t mat]ial sub/ance 9 a highly dilut$ or gase\s =m exi/s 9 va/ abundance4 ,! numb] ( ! nebul1 l t ( ! />s1 is only limit$ by ! imp]fection ( our in/rum5ts1 = ea* improvem5t 9 ! telescope only enables u to p5etrate a little f>!r into ! inf9ity ( space--to see a few m ( ^! %ad[y exi/5ces 9 ! f> di/ance1 & to resolve a few m ( ^? t are comp>atively ne>4 ,sir ,william ,h]s*el exam9$ ! nature & det]m9$ ! position ( #bejj nebul 9 ! nor!rn hemisph]e ^: places 7 comput$ f 8 obs]vations1 r$uc$ to a common epo*1 & arrang$ into a catalogue1 9 ord] ( "r asc5sion1 by 8 si/]1 ,miss ,c>ol9e ,h]s*el1 :o add$ lu/re to ! "n %e bore by h] em95ce 9 a/ronomical k & discov]y4 ,sir ,john ,h]s*el revis$ 8 fa!r's obs]vations1 & add$ #hjj nebul to ! catalogue be=e he w5t to ! ,cape ( ,good ,hope1 9 ord] to complete ! survey ( ! heav5s4 ,on 8 return he publi%$ a catalogue ( #bjdi nebul ( ! s\!rn hemisph]e1 ( :i* #ejj 7 previ\sly unkn[n1 ) _! position 9 ! heav5s4 ,9 a "w unp>allel$ = elegance ( /yle1 dep? ( k1 & orig9ality ( views1 he has giv5 engrav+s f 8 draw+s ( ! mo/ rem>kable objects1 s t :atev] *anges may take place 9 _! =m1 place1 or cond5sation1 w be kn[n by a/ronom]s ( future ages4 ,?\gh inf9ite 9 v>iety1 ! nebul are ( two di/9ct classes2 "o consi/s ( pat*es ( great dim5sions1 caprici\sly irregul>1 assum+ all ! fanta/ic =ms ( cl\ds1 n[ bright1 n[ obscure2 sometimes l vap\r fly+ be=e ! w9d2 sometimes /ret*+ long arms into space4 ,_m pres5t an ill-def9$ surface1 9 :i* x is difficult to say :]e ! c5tre ( ! greate/ brightness is4 ,l>ge portions are resolvable into />s2 _m h a granulat$ appe>ance1 z if !y 7 resolvable2 & o!rs probably are n s m]ely f ! smallness & clos5ess ( ! />s1 & possibly f _! remot5ess1 indicat+ ! complex & irregul> =m ! ,milky ,way w\ld pres5t if se5 f a di/ance4 ,a wond]ful nebula ( ?is k9d is visible to ! nak$ eye 9 ! con/ellation ( ,orion2 x is ( va/ ext5t1 s5d+ bran*es ev5 into ! s\!rn hemisph]e2 &1 al?\gh ,"l ,rosse's telescope has resolv$ mu* t _h hi!rto resi/$ o!rs1 !re are p>ts t /ill ma9ta9 _! nebul\s appe>ance f extreme remot5ess1 pres5t+ a k9d ( mottl$ aspect1 l flocks or wisps ( wool1 or mack]el sky4 ,!re c be no d\bt ( its be+ an unfa?omable cong]ies ( />s1 :i* !re is reason to believe has *ang$ its =m 9 "s p>ts )9 ! la/ fifty ye>s4 ,va/ multitudes ( nebul ( ?is k9d are s fa9t z to be ) difficulty disc]n$ at all till !y h be5 = "s "t 9 ! field ( ! telescope1 or are j ab\t to quit x4 ,occasionally !y are s vague1 t ! eye is consci\s ( some?+ be+ pres5t1 )\t be+ able to def9e :at x is2 b ! un*angeabl5ess ( its position conv9ces ! m9d t x is a real object--8an image 0 be=e m9e eyes1 b ,i c\ld n disc]n ! =m !re(40 ,no draw+ c give an idea ( ! b\nd>ies ( su* nebul z t ( ,orion2 ev5 ) ,"l ,rosse's telescope ! edges ei!r fade into a lum9\s mi/1 :i* becomes m r>e till x is imp]ceptible1 or end 9 a tissue ( fa9ti% flocculi1 or 9 filam5ts :i* become f9] & m scatt]$ till !y cease to be visible1 %[+ t ! real b\nd>ies h n be5 se54 ,! o!r class ( nebul1 va/ly inf]ior 9 size1 ( def9ite =ms & great v>iety ( "*1 are scatt]$ ?r\gh ! remote heav5s1 or congregat$ 9 a great nebul\s di/rict f> f ! ,milky ,way4 ,_m cl+ to />s l wisps ( cl\ds1 o!rs are exactly l comets ) com & tails2 b ! mo/ def9ite =ms are annul> & l5ticul> nebul1 nebul\s />s1 planet>y & elliptical nebul1 & />ry clu/]s4 ,h[ev]1 !re are two 9 ! nor!rn hemisph]e diff]+ f all ( ^!1 :i* are describ$ by ,sir ,john ,h]s*el z amaz+ objects4 ,"o 9 ,vulpecula is l an h\rglass or dumb bell ( bright matt]1 surr\nd$ by a ?9 hazy atmosph]e s z to give ! :ole an oval =m1 or ! appe>ance ( an oblate sph]oid2 ) a high] optical p[] its =m is mu* ! same1 b ! bright] "p is resolv$ into />s1 & ! hazy "p1 ?\gh /ill nebul\s1 assumes t mottl$ appe>ance :i* %[s t ! :ole is a /ell> sy/em ( ! mo/ peculi> /ructure3 x is a ph5om5on t be>s no resemblance to any kn[n object4 7,fig4 #c1 plate #h1 & fig4 #c1 plate #i74 ,! o!r is inde$ mo/ wond]ful1 & its hi/ory %[s ! gradual increase 9 ! space-p5etrat+ p[] ( telescopes4 ,to ,messi] x appe>$ m]ely to be a d\ble nebula ) />s2 ) ,sir ,william ,h]s*el's telescope x pres5t$ ! appe>ance ( a bright r\nd nebula encompass$ at a little di/ance by a halo or glory1 & accompani$ by a companion2 :ile 9 ,sir ,john ,h]s*el's #bj feet reflector x appe>$ to 8consi/ ( a bright r\nd nucleus1 surr\nd$ at a di/ance by a nebul\s r+ split ?r\gh half its circumf]5ce1 & hav+ ! split portions sep>at$ at an angle ( #de degrees ea* to ! plane ( ! o!r40 7,fig4 #a1 plate #aj47 ,?is nebula appe>$ to ,sir ,john to 8be> a /rong similitude to ! ,milky ,way1 sugge/+ ! idea ( a bro!r sy/em be>+ a real physical resemblance & /rong analogy ( /ructure to our own40 ,?is object1 :i* disclos$ to ,"l ,rosse ! a/oni%+ ph5om5on ( spiral nebul se5 9 8 telescope1 pres5ts ! appe>ance ( ! fig4 #a 9 plate #aj1 9 :i* ! p>tial division ( ! limb ( ! r+ into two bran*es is at once recognis$ 9 ! bright convolutions ( ! spiral4 ,! outly+ nebula is connect$ by a n>r[ curv$ b& ( light ) ! r+2 ! :ole is ei!r resolv$ into />s1 or evid5tly might be ) a /ill high] optical p[]4 ,) reg>d to ! m>vell\s nebula 9 "q ,"l ,rosse obs]ves1 t 8) ea* increase ( optical p[] ! /ructure has become m complicat$1 & m unlike any?+ t c\ld result f any =m ( a dynamical law ( :i* we f9d a c\nt]p>t 9 our sy/em4 ,! connection ( ! companion ) ?is great nebula1 ( :i* !re is n ! lea/ d\bt1 adds to ! difficulty ( =m+ any hypo!sis4 ,x is impossible t su* a sy/em c\ld exi/ )\t int]nal movem5t1 to :i* may be add$ a resi/+ m$ium2 b x _c be reg>d$ z a case ( m]e /atic equilibrium40 ,?is is by no means ! only in/ance ( a spiral nebula2 ,"l ,rosse has discov]$ sev]al o!rs3 "s are easily se5--o!rs require ! highe/ p[]s ( 8 telescope4 ,f ! num]\s (fsets t bran* f ! ,milky ,way & run f> into space1 x may possibly p>take also ( ! spiral =m4 ,!re are sev5 annul> nebul 9 ! nor!rn hemisph]e1 s9ce ,"l ,rosse has discov]$ t five ( ! planet>y nebul belong to ?is class4 ,"o ( ! f9e/ examples ( an annul> nebula is to be se5 midway betwe5 & ,lyr 7fig4 #b1 plate #i74 ,accord+ to ,sir ,john ,h]s*el1 x is elliptical 9 ! ratio ( #d to #e1 & is %>ply def9$--! int]nal op5+ occupy+ ab\t half ! diamet]4 ,?is op5+ is n entirely d>k1 b fill$ ) a fa9t hazy light l f9e gauze /ret*$ ov] a hoop4 ,its diamet]1 if x is z f> f u z #fa ,cygni1 mu/ be #acjj times great] ?an ! diamet] ( ! e>?'s orbit--dim5sions t are mo/ a/\nd+4 ,"l ,rosse's telescope resolves ?is object into />s ( extreme m9ut5ess1 ) filam5ts ( />s adh]+ to its edges & a pretty bright /> 9 its int]ior4 ,^! r+s are l holl[ %ells ^: bord]s seem bright] because ! nebul\s sub/ance1 :atev] x may be1 is m cond5s$ to appe>ance ?an ! c5tral "p4 ,! o!r annul> nebula 9 ! nor!rn hemisph]e describ$ by ,sir ,john ,h]s*el is a small fa9t object1 & m easily resolvable into />s4 ,"o ( ! annul> nebul se5 by ,"l ,rosse is surr\nd$ by a fa9t ext]nal flat r+2 ano!r has ans1 z if an annul> nebul\s r+ encompass$ x & 0 =e%ort5$4 ,two annul> nebul h p]=ations z if ! black sky 0 se5 ?r\gh op5+s 9 ! int]ior haze1 = 9 no in/ance is ! c5tral op5+ q d>k4 ,"s nebul are l v elliptical annul> sy/ems se5 obliquely4 ,if !y be elliptical flat r+s1 ! d>k c5tre may be a real op5+2 b %\ld ! sy/ems be a s]ies ( v long elliptical conc5tric %ells surr\nd+ a holl[1 ! d>k axis may be m]ely a l9e ( comp>ative d>kness4 ,! connection ( ! elliptical nebul ) d\ble />s is m5tion$ z v rem>kable4 ,9 "o elliptical nebula ^: long] axis is #ej !re are two individuals ( a d\ble /> ea* ( ! #aj? magnitude symmetrically plac$ r ne>] ! v]tex ( ! ellipse ?an ! foci2 9 ano!r ! />s are unequal1 b plac$ exactly at ! extremities ( ! major axis1 z 9 plate #h3 besides ^! !re are sev]al o!r in/ances4 ,d\ble nebul are n unfrequ5t 9 bo? hemisph]es1 exhibit+ all ! v>ieties ( di/ance1 position1 & relative brightness1 ) _! c\nt]p>ts ! d\ble />s4 ,! r>ity ( s+le nebul z l>ge1 fa9t1 & z little cond5s$ 9 ! c5tre z ^!1 makes x extremely improbable t two su* bodies %\ld be accid5tally s ne> z to t\*1 & (t5 9 "p to ov]lap ea* o!r1 z ^! d4 ,x is mu* m likely t !y con/itute sy/ems2 &1 if s1 x w =m an int]e/+ object ( future inquiry to discov] :e!r !y possess orbital motion4 ,nebul\s />s are beautiful objects1 q diff]5t f all ! prec$+4 ,!y are r\nd or oval1 increas+ 9 d5sity t[>ds ! c5tre4 ,sometimes ! c5tral matt] is s vividly & %>ply cond5s$ & def9$ t ! nebula might be tak5 = a bright /> surr\nd$ by a ?9 atmosph]e4 ,"o is a /> ( ! #h? magnitude exactly 9 ! c5tre ( a r\nd bright atmosph]e #be 9 diamet]2 ! /> is q /ell>1 & n a nucleus3 x has n ! smalle/ appe>ance ( be+ resolvable4 ,ano!r nebul\s /> is ,orionis1 :i* has a broad atmosph]e 9 :i* is a d>k cavity n symmetrical ) ! />1 & a small d\ble /> ) a simil> op5+ on ! edge ( ! atmosph]e4 ,"l ,rosse obs]ves t ^! op5+s appe> to be ( ! same nature ) t )9 ! bright />s 9 ! trapezium ( ,orion1 ! />s be+ at its edge2 & he is conv9c$ t ! />s are n only connect$ ) ! nebula1 b t !y are equidi/ant ) x2 h5ce1 if _! p>allax c be f\nd1 ! di/ance ( ?is nebula w\ld be det]m9$4 ,! zodiacal light or l5ticul> %ap$ lum9\s haze surr\nd+ ! sun :i* may be se5 ext5d+ beyond ! orbits ( ,m]cury & ,v5us soon aft] sunset 9 ! mon?s ( ,april & ,may1 or be=e dawn 9 ,novemb] & ,decemb]1 seems to place our lum9>y 9 ! class ( nebul\s />s4 ,! ext5sive & delicate atmosph]e ( ^! nebul\s />s assumes all degrees ( ellipticity1 f ! circul> to ! sp9dle-%ap$ ray1 or almo/ ! "r l9e4 ,planet>y nebul h exactly ! appe>ance ( planets ) r\nd or oval discs1 sometimes %>ply t]m9at$1 at o!r times hazy & ill-def9$4 ,_! surface1 :i* is blue or bluei% :ite1 is equable or slightly mottl$1 & _! light occasionally rivals t ( ! planets 9 vividness4 ,!y are g5]ally att5d$ by m9ute />s1 :i* give ! idea ( accompany+ satellites4 ,^! nebul are ( enorm\s dim5sions4 ,"o ne> ,aqu>ii has a s5sible diamet] ( ab\t tw5ty seconds1 & ano!r pres5ts a diamet] ( twelve4 ,sir ,john ,h]s*el has comput$ t1 if ^! objects be z f> f u z ! />s1 _! real magnitude1 on ! l[e/ e/imation1 mu/ be su* z w\ld fill ! orbit ( ,uranus4 ,he concludes t1 if !y be solid bodies ( a sol> nature1 _! intr9sic spl5d\r mu/ be f> inf]ior to t ( ! sun1 because a circul> portion ( ! sun's disc subt5d+ an angle ( tw5ty seconds w\ld give a light equal to t ( a hundr$ full moons2 :ile1 on ! contr>y1 ! objects 9 "q are h>dly1 if at all1 visible to ! nak$ eye4 ,f ! uni=mity ( ! discs ( ^! planet>y nebul1 & _! app>5t want ( cond5sation1 he presumes t !y may be holl[ %ells emitt+ light f _! surface only4 ,! s\!rn hemisph]e is v ri* 9 !m1 :]e tw5ty-eight or tw5ty-n9e h be5 discov]$1 "s 9 ! mid/ ( a clu/] ( />s1 ) :i* !y =m a beautiful contra/4 ,?ree are ( a decid$ blue col\r1 "o ,prussian blue1 or v]dit] gre51 ! o!r two ( a bright sky blue1 ( great beauty & delicacy4 ,"o seems to belong to ! class ( d\ble nebul or d\ble /ell> nebul ( ! utmo/ remot5ess4 ,s9ce ,"l ,rosse's telescope has %[n t five ( ! planet>y nebul are annul>1 "s ( ^? 9 ! s\!rn hemisph]e may ultimately be f\nd to belong to ! same class4 ,probably n9e t5?s at lea/ ( ! nebul\s cont5ts ( ! heav5s consi/ ( sph]ical or elliptical =ms pres5t+ e v>iety ( elongation & c5tral cond5sation4 ,( ^! a great numb] h be5 resolv$ into />s1 & a great _m pres5t t mottl$ appe>ance :i* r5d]s x c]ta9 t an increase ( optical p[] w\ld decompose !m4 ,^? :i* resi/ d s on acc\nt ( ! smallness & clos5ess ( ! />s ( :i* !y consi/4 ,elliptical nebul are v common2 by mu* ! f9e/ may be se5 ne> ! /> 9 ! girdle ( ,&rom$a4 ,x is visible to ! nak$ eye1 & has frequ5tly be5 tak5 = a comet4 ,) a l[ optical p[] x has ! sp9dle-%ap$ =m ( fig4 #f1 plate #e1 ! brightness be+ at fir/ gradually & !n rapidly cond5s$ t[>ds ! c5tre1 s t x has be5 comp>$ to a /> %9+ ?r\gh horn1 b _h nev] appe>$ resolvable ev5 ) high optical p[]s till ,mr4 ,bond exam9$ x at ! obs]vatory ( ,cambridge 9 ! ,unit$ ,/ates4 ,he f\nd t its brightness ext5ds ov] #b-a_/b degrees 9 l5g?1 & m ?an a degree 9 bread?1 includ+ two small adjac5t nebul1 s t x is oval4 ,x is /rongly & rapidly cond5s$ into a nucleus on its nor!rn side2 & al?\gh x 0 n all resolv$1 x 0 se5 to be /rew$ ov] ) /> du/1 or extremely m9ute visible />s1 :i* leaves n a d\bt ( its be+ a />ry sy/em4 ,! mo/ rem>kable "p ( ,mr4 ,bond's discov]y are two v n>r[ d>k l9es :i* ext5d along "o side ( ! oval p>allel to its major axis4 ,^! black /reaks1 difficult to di/+ui%1 indicate a /ratifi$ /ructure1 & are n ! only in/ance ( t arrangem5t 9 nebul4 ,fig4 #a1 9 plate #i1 is f ,mr4 ,bond's draw+ ( ?is nebula4 ,multitudes ( nebul appe> to ! unassi/$ eye1 or are se5 ) ord9>y telescopes1 l r\nd comets )\t tails2 b :5 view$ ) p[]ful in/rum5ts !y convey ! idea ( a globul> space1 insulat$ 9 ! heav5s & full ( />s1 con/itut+ a family or society ap>t f ! re/1 subject only to its own int]nal laws4 ,to attempt to c\nt ! />s 9 "o ( ^! globul> clu/]s1 ,sir ,john ,h]s*el says1 w\ld be a va9 task2 !y are n to be reckon$ by hundr$s4 ,on a r\gh computation1 x appe>s t _m clu/]s ( ?is description mu/ conta9 t5 or tw5ty ?\s& />s compact$ & w$g$ toge!r 9 a r\nd space1 ^: app>5t area is n m ?an a t5? "p ( t cov]$ by ! moon2 s t its c5tre1 :]e ! />s are se5 project$ on ea* o!r1 is "o blaze ( light4 ,if ea* ( ^! />s be a sun1 & if !y be sep>at$ by int]vals equal to t :i* sep>ates our sun f ! ne>e/ fix$ />1 ! di/ance :i* r5d]s ! :ole clu/] b>ely visible to ! nak$ eye mu/ be s great1 t ! exi/5ce ( su* a spl5did assemblage c only be kn[n to u by light :i* mu/ h left x at lea/ a ?\s& ye>s ago4 ,^! magnific5t globul> or sph]oidal aggregates ( />s are s arrang$ t ! int]ior /rata are m cr[d$ & become m ne>ly sph]ical z !y approa* ! c5tre4 ,a mo/ spl5did object ( ?is nature may be se5 9 ! con/ellation ,h]cules 7,n4 #bce74 ,( #aca ( ^! magnific5t objects 9 ! s\!rn hemisph]e1 two ( !m are pre-em95tly spl5did4 ,! globul> clu/] ( ,c5tauri is beyond comp>ison ! f9e/ ( its k9d3 x is p]fectly sph]ical1 & occupies a qu>t] ( a squ>e degree2 ! />s 9 x are lit]ally innum]able1 cr[d+ & d5sely aggregat$ t[>ds ! c5tre2 &1 z its light is n m to ! nak$ eye ?an t ( a /> ( ! #d? or #e? magnitude1 _! m9ut5ess is extreme4 ,x has a d>k hole 9 its c5tre1 ) a bridge ( />s across1--a circum/ance peculi> to ?is clu/]4 ,lacaille's globul> clu/]1 or #dg ,t\cani1 is completely insulat$ 9 a v d>k "p ( ! sky n f> f ! less] ( ! ,magellanic cl\ds4 ,! />s1 :i* are ( ! #ad? magnitude1 imm5sely num]\s1 compress$ & :ite1 =m ?ree di/9ct /ages r\nd a c5tre1 :]e !y sudd5ly *ange 9 hue1 & =m a blaze ( rose-col\r$ light4 ,"o clu/] consi/s ( l>ge ruddy />s & small :ite ones2 ano!r ( great] beauty consi/s ( %ells or coats ( />s ( ! #aa? & #ae? magnitude4 ,!re are ?irty globul> clu/]s ( extreme beauty collect$ )9 a circul> space ( n m ?an eighte5 degrees radius1 :i* lies 9 ! "p ( ! sky occupi$ by ! con/ellations ,corona ,au/ralis1 ! body & head ( ,sagitt>ius1 ! tail ( ,scorpio1 "p ( ,telescopium & ,ara4 ,! ,milky ,way passes diametrically across ! circul> area 9 "q1 :i* gives prodigi\s brilliancy to ?is "p ( ! sky4 ,= besides ^! globul> clu/]s1 :i* all lie 9 ! />ry "p1 & n 9 ! d>k spaces1 !re are ! only two annul> nebul kn[n to exi/ 9 ! s\!rn hemisph]e4 ,no "p ( ! heav5s is full] ( objects beautiful & rem>kable 9 !mselves1 & r5d]$ /ill m s by _! mode ( association1 & by ! peculi> features assum$ by ! ,milky ,way1 :i* are )\t a p>allel = ri*ness & magnific5ce 9 any o!r "p ( ! sky4 ,"s ( ! globul> clu/]s are s remote t ! />s are sc>cely disc]nible--m]e /> du/4 ,!re is a d\ble globul> clu/] 9 ! s\!rn hemisph]e ( v small dim5sions1 sep>at$ by a m9ute int]val1--a comb9ation :i* sugge/s ! idea ( a globul> clu/] revolv+ ab\t a v oblate sph]oidal "o 9 ! plane ( ! equator1 & 9 an orbit :i* is circul>1 & se5 obliquely l ! c5tral nebula itself1 ) a diamet] some:at m ?an f\r times ! latt]1--a /up5d\s sy/em d\btless1 b ( :i* ! reality c h>dly be suppos$ improbable4 ,!re appe>s to be "s connexion betwe5 ellipticity ( =m & difficulty ( resolution1 = sph]ical clu/]s are 9 g5]al easily resolv$ into _! compon5t />s1 :ile !re is sc>cely an in/ance ( an elliptical clu/] yield+ except to a v high optical p[]4 ,va/ masses ( ! nebul h nev] be5 resolv$4 ,"l ,rosse's great telescope has resolv$ p>ts ( ! nebula ( ,orion1 & v>i\s o!rs :i* _h n yield$ to in/rum5ts ( less p[]2 x enables ! a/ronom] to p5etrate f>!r into space1 & %[s objects ) great] cle>ness1 ?an any o!r4 ,b1 excell5t z ?is in/rum5t is1 ?\s&s ( nebul are n to be resolv$ ev5 by x4 ,^? :o imag9e t any "w ( man c resolve all ! nebul\s matt] 9 ! heav5s mu/ h a v limit$ idea ( ! ext5t & sublimity ( creation4 ,innum]able nebul 9 bo? hemisph]es take ! =m ( clu/]s ( />s1 b are totally diff]5t f ! globul> clu/]s1 inasmu* z !y are ( irregul> =m & foll[ no uni=m law ( cond5sation4 ,! ,pleiades is an in/ance 9 our own /ell> sy/em2 = al?\gh only #g or #h />s are visible to ! nak$ eye1 telescopes %[ t m ?an #bjj belong to ! gr\p4 ,9 ! con/ellation ,canc] !re is a lum9\s spot call$ ! ,prsepe or ,beehive1 :i* a v l[ p[] resolves into />s2 & ! con/ellation ,coma ,b]5ices is ano!r /ell> gr\p4 ,_m are ( exquisite beauty1 z t r\nd ,crucis1 :i*1 ?\gh consi/+ ( only a hundr$ & t5 />s1 is l a piece ( fancy jewell]y1 f ! col\rs ( ! />s1 :i* are gre5i% :ite1 gre51 bluei% gre51 & r$4 ,_m ( ^! clu/]s conta9 ?\s&s ( />s1 & are frequ5tly 9 ! poor] p>ts ( ! sky1 z if 9 ! c\rse ( ages ! />s _h be5 attract$ t[>ds a c5tre4 ,! exi/5ce ( e degree ( ellipticity 9 ! nebul--f long l5ticul> rays to ! exact circul> =m--& ( e %ade ( c5tral cond5sation1 f ! slighte/ increase ( d5sity to app>5tly a solid nucleus--may be acc\nt$ = by suppos+ ! g5]al con/itutions ( ^? nebul to be t ( oblate sph]oidal masses ( e degree ( flatness f ! sph]e to ! disc1 & ( e v>iety 9 _! d5sity & ellipticity t[>ds ! c5tre4 ,x w\ld be errone\s1 h[ev]1 to imag9e t ! =ms ( ^! sy/ems are ma9ta9$ by =ces id5tical ) ^? already describ$1 :i* det]m9e ! =m ( a fluid mass 9 rotation2 because1 if ! nebul be only clu/]s ( sep>ate />s1 z 9 ! great] numb] ( cases !re is e reason to believe !m to be1 no pressure c be propagat$ ?r\gh !m4 ,consequ5tly1 s9ce no g5]al rotation ( su* a sy/em z "o mass c be suppos$1 x may be conceiv$ to be a quiesc5t =m1 compris+ )9 its limits an indef9ite numb] ( />s1 ea* ( :i* may be mov+ 9 an orbit ab\t ! common c5tre ( ! :ole1 9 virtue ( a law ( int]nal gravitation result+ f ! comp\nd gravitation ( all its p>ts4 ,sir ,john ,h]s*el has prov$ t ! exi/5ce ( su* a sy/em is n inconsi/5t ) ! law ( gravitation "u c]ta9 conditions4 ,! di/ribution ( ! nebul ov] ! heav5s is ev5 m irregul> ?an t ( ! />s4 ,9 "s places !y are s cr[d$ toge!r z sc>cely to all[ "o to pass ?r\gh ! field ( ! telescope be=e ano!r appe>s1 :ile 9 o!r p>ts h\rs elapse )\t a s+le nebula occurr+4 ,!y are 9 g5]al only to be se5 ) ! be/ telescopes1 & are mo/ abundant 9 a zone ^: g5]al direction is n f> f ! h\r circles #j;h & #ab;h1 & :i* crosses ! ,milky ,way ne>ly at "r angles4 ,:]e t nebul\s zone passes ov] ! con/ellations ,virgo1 ,coma ,b]5ices1 & ! ,great ,be>1 !y are to be f\nd 9 multitudes4 ,! nebul\s sy/em is ne>ly divid$ into two p>ts by ! ,milky ,way4 ,"o-?ird ( ! :ole visible nebul\s cont5ts ( ! heav5s =ms a broad irregul> mass1 int]sp]s$ ) vacant int]vals1 :i* fills ab\t an eigh? ( ! surface ( ! nor!rn hemisph]e4 ,x occupies ! con/ellations ,leo1 ,leo ,m9or1 ! body1 tail1 & h9d legs ( ,ursa ,major1 ! nose ( ,camelop>d1 ! po9t ( ! tail ( ,draco1 ,canis ,v5atica1 ,coma ,b]5ices1 ! prec$+ leg ( ,botes1 & ! head1 w+s1 & %\ld] ( ,virgo1 :i* is ! ri*e/ "p4 ,!re is a less] nebul\s region 9 ?is hemisph]e1 b entirely sep>at$ f ! prec$+1 :i* occupies ! *e/ & w+ ( ,pegasus1 ! con/ellations ,pisces & ,&rom$a4 ,if we c\ld imag9e ! r+ or zone ( ! ,milky ,way to encircle or co9cide ) ! horizon1 ! great nebul\s mass w\ld =m a canopy ov] head1 desc5d+ d[n to a consid]able di/ance on all sides1 *iefly t[>ds ! nor? pole2 & ! ri*e/ "p1 :i* is 9 ,virgo1 w\ld !n be directly ov] head 9 ! nor? pole ( ! ,milky ,way1 t is 9 #ab;h #dgm "r asc5sion1 & #fd nor? pol> di/ance4 ,) ! exception ( ! ,magellanic cl\ds1 !re is a mu* great] uni=mity 9 ! di/ribution ( ! nebul 9 ! s\!rn hemisph]e ?an 9 ! nor!rn4 ,!y are sep>at$ by spaces ( vacuity ( great] or less dim5sions4 ,"o ( ^! b>r5 regions ext5ds = ne>ly fifte5 degrees all ar\nd ! s\? pole1 & close on its bord]2 ! less] ( ! ,magellanic cl\ds occurs completely insulat$2 :ile ! great] ,magellanic cl\d is 9 connexion ) some?+ approa*+ to a zone ( connect$ nebul\s pat*es :i* ext5ds along ! back ( ,doradus1 ?r\gh a portion ( ,horologium & ,eridanus1 "p ( ,=nix1 & ov] ! paws ( ,cetus to ! equator1 :]e x unites ) ! nebul\s regions ( ,pisces4 ,! ,magellanic cl\ds =m two ( ! mo/ /rik+ features 9 ! s\!rn hemisph]e2 bo? ( ^! nebul are visible to ! unassi/$ eye1 be+ ne>ly ( ! same int5sity z ! bright] portions ( ! ,milky ,way2 b ! small] is entirely effac$ by moonlight1 & ! l>g] ne>ly s4 ,!y are altoge!r unconnect$ ) ! ,milky ,way & ) "o ano!r4 ,! ,nubecula ,major is f> sup]ior to ! ,nubecula ,m9or 9 e respect1 ?\gh !y are simil> 9 int]nal /ructure4 ,! =m] consi/s ( l>ge tracts & ill-def9$ pat*es ( irresolvable nebul1 & nebulosity 9 e /age ( resolution1 up to p]fectly resolv$ />s l ! ,milky ,way2 & also ( regul> & irregul> nebul1 prop]ly s call$2 ( globul> clu/]s 9 e /age ( resolvability2 & ( clu/]+ gr\ps suffici5tly insulat$ & cond5s$ to come "u ! designation ( clu/]s ( />s4 ,( ^! ! nebula kn[n z ,lacaille's #cj ,doradus is too rem>kable to be pass$ ov]4 ,x is v l>ge1 situate )9 ! ,nubecula ,major1 & consi/s ( an assemblage ( ne>ly circul> loops unit+ 9 a c5tre1 9 or ne> :i* !re is a circul> black hole4 ,9 %ort1 = ! numb] & v>iety ( ! objects1 !re is no?+ l ?is cl\d4 ,)9 an area ( only =ty-two squ>e degrees1 ,sir ,john ,h]s*el has det]m9$ ! places1 & regi/]$ #bgh nebul & clu/]s ( />s1 ) fifty or sixty 9 outly+ memb]s imm$iately adjac5t4 ,ev5 ! mo/ cr[d$ p>ts ( ! /ratum ( ,virgo1 9 ! w+ ( t con/ellation1 or 9 ,coma ,b]5ices1 (f] no?+ approa*+ to x4 ,x is evid5t1 f ! int]mixture ( />s & unresolv$ nebulosity1 :i* probably might be resolv$ ) a high] optical p[]1 t ! nubecul are to be reg>d$ z sy/ems sui g5]is1 to :i* !re is no?+ analog\s 9 our hemisph]e4 ,next to ! ,magellanic cl\ds ! great nebula r\nd ,args is "o ( ! mo/ wond]ful objects ( ! s\!rn sky4 ,x is situate 9 t "p ( ! ,milky ,way :i* lies betwe5 ! ,c5taur & ! body ( ,argus1 9 ! mid/ ( "o ( ^? ri* & brilliant masses1 a succession ( :i* is s curi\sly contra/$ ) ! pr(\ndly d>k adjac5t spaces1 & surr\nd$ by "o ( ! mo/ beautiful p>ts ( ! s\!rn heav5s4 ,sir ,john ,h]s*el says3 8,x w\ld be impossible1 by v]bal description1 to give any j idea ( ! caprici\s =ms & irregul> gradations ( light affect$ by ! diff]5t bran*es & app5dages ( ?is nebula4 ,nor is x easy = language to convey a full impression ( ! beauty & sublimity ( ! spectacle x (f]s :5 view$ 9 a sweep1 u%]$ 9 z x is by s glori\s & innum]able a procession ( />s1 to :i* x =ms a sort ( climax1 ju/ify+ expressions :i*1 ?\gh ,i f9d !m writt5 9 my j\rnal 9 ! excitem5t ( ! mom5t1 w\ld be ?\ght extravagant if transf]r$ to ^! pages4 ,9 fact1 x is impossible = any "o1 ) ! lea/ sp>k ( a/ronomical en?usiasm ab\t him1 to pass sob]ly 9 review ) a p[]ful telescope1 & on a f9e night1 t portion ( ! s\!rn sky :i* is compris$ betwe5 ! #f? & #ac? degrees ( "r asc5sion1 & f #adf to #adi ( nor? pol> di/ance2 su* are ! v>iety & int]e/ ( ! objects he w enc\nt]1 & su* ! dazzl+ ri*ness ( ! />ry gr\nd on :i* !y are repres5t$ to 8 gaze40 ,9 t portion ( ! sky !re are _m f9e d\ble />s--ri* />ry clu/]s2 ! elegant clu/] ( v>i\sly col\r$ />s r\nd ,crucis2 a l>ge planet>y nebula ) a satellite />2 ano!r ( a bright blue col\r1 exquisitely beautiful & unique2 &1 la/ly1 ,args itself1 ! mo/ extraord9>y in/ance ( a v>iable /> 9 a/ronomical hi/ory4 ,x frequ5tly occurr$1 dur+ ,sir ,john ,h]s*el's survey ( ! s\!rn heav5s1 t "s p>ts ( ! sky 7 not$ = deep] blackness ?an o!rs1 & no />s c\ld be se52 x frequ5tly happ5$ t f> f ! ,milky ,way1 or any l>ge nebula or clu/] ( />s1 !re 7 "s indications ( v remote bran*es ( ! ,milky ,way1 or ( an indep5d5t sid]eal sy/em or sy/ems1 be>+ a resemblance to su* bran*es4 ,^! 7 indicat$ by an exce$+ly delicate & uni=m dott+ or /ippl+ ( ! sky by po9ts ( light too small to admit ( any "o ( !m be+ /eadily & fix$ly view$1 & too num]\s to be c\nt$ ev5 if possible to view !m4 ,! tru? ( ?is exi/5ce 0 felt at ! mom5t ( obs]vation2 b ! conviction1 ?\gh (t5 r5ew$1 0 n p]man5t4 ,! places :]e ^! appe>ances occurr$ are giv51 9 ord] t ^? :o wi% to v]ify !m may h x 9 _! p[]4 ,su* is a brief acc\nt ( a v few ( ! discov]ies conta9$ 9 ,sir ,john ,h]s*el's great "w on ! ,nebul & o!r ,ph5om5a ( ! ,s\!rn ,hemisph]e1--a "w :i* w rise 9 e/imation ) ! lapse ( ye>s4 ,no d\bt ! =m & int]nal /ructure ( _m ( ^! nebul w be *ang$ by telescopes ( high] p[]2 b z ! places ( ! lead+ ph5om5a h be5 det]m9$1 ! date ( t great "w may be reg>d$ z ! epo* ( nebul> "t :5ce ! relative *anges t take place 9 ! mo/ di/ant regions ( ! univ]se w be e/imat$ = ages to come2 & 9 ! inimitable writ+s ( ! highly gift$ fa!r & son ! read] w f9d ^! subjects treat$ ( 9 a /yle wor?y ( x & ( !m4 ,( late ye>s ! excell5ce ( ! in/rum5ts1 & /ill m ( ! a/ronom]s1 9 ! =eign obs]vatories1 h aid$ ! progress ( sid]eal a/ronomy imm5sely4 ,nor has x be5 cultivat$ ) less success 9 our home & colonial e/abli%m5ts3 c]ta9ly "o ( ! mo/ rem>kable features ( ! times is ! numb] ( private obs]vatories1 built & furni%$ ) ! be/ in/rum5ts by private g5tlem51 ^: zeal has be5 rew>d$ by em95t success 9 all dep>tm5ts ( ! sci5ce4 7,n4 #bcf47 ,s num]\s are ! objects :i* meet our view 9 ! heav5s1 t we _c imag9e a po9t ( space :]e "s light w\ld n /rike ! eye2--innum]able />s1 ?\s&s ( d\ble & multiple sy/ems1 clu/]s 9 "o blaze ) _! t5s ( ?\s&s ( />s1 & ! nebul amaz+ u by ! /rang5ess ( _! =ms & ! incompreh5sibility ( _! nature1 till at la/1 f ! limit ( our s5ses1 ev5 ^! ?9 & airy phantoms vani% 9 ! di/ance4 ,if su* remote bodies %one by reflect$ light1 we %\ld be unconsci\s ( _! exi/5ce4 ,ea* /> mu/ !n be a sun1 & may be presum$ to h its sy/em ( planets1 satellites1 & comets1 l our own2 &1 = aught we "k1 myriads ( bodies may be w&]+ 9 space unse5 by u1 ( ^: nature we c =m no idea1 & /ill less ( ! "p !y p]=m 9 ! economy ( ! univ]se4 ,ev5 9 our own sy/em1 or at its f>!/ limits1 m9ute bodies may be revolv+ l ! telescopic planets1 :i* are s small t _! masses h hi!rto be5 inappreciable1 & !re may be _m /ill small]4 ,nor is ?is an unw>rant$ presumption2 _m su* d come )9 ! sph]e ( ! e>?'s attraction1 are ignit$ by ! velocity ) :i* !y pass ?r\gh ! atmosph]e1 b leave no residuum4 ,^!1 :i* are kn[n z fall+ />s & meteors1 are p]iodical2 b t is by no means ! case ) arolites1 :i* are also ignit$ by ! sudd5 cond5sation ( ! air on ent]+ our atmosph]e1 & are precipitat$ 9 solid masses ) su* viol5ce on ! e>?'s surface t !y are (t5 deeply buri$ 9 ! gr\nd4 ,! fall ( meteoric /ones is mu* m frequ5t ?an is g5]ally believ$4 ,h>dly a ye> passes )\t "s in/ances occurr+2 &1 if x be consid]$ t only a small "p ( ! e>? is inhabit$1 x may be presum$ t numb]s fall 9 ! ocean1 or on ! un9habit$ "p ( ! l&1 unse5 by man4 ,!y are sometimes ( great magnitude2 ! volume ( sev]al has exce$$ t ( ! planet ,c]es1 :i* is ab\t #gj miles 9 diamet]4 ,"o :i* pass$ )9 #be miles ( u 0 e/imat$ to weigh ab\t #fjj1jjj tons1 & to move ) a velocity ( ab\t #bj miles 9 a second2 a fragm5t ( x alone rea*$ ! e>?4 ,! obliquity ( ! desc5t ( meteorites1 ! peculi> sub/ances !y are compos$ (1 & ! explosion accompany+ _! fall1 %[ t !y are =eign to our sy/em2 b :5ce d]iv$ is /ill a my/]y4 ,%oot+ />s & meteors bur/ f ! cle> azure sky1 &1 d>t+ along ! heav5s1 are ext+ui%$ )\t leav+ any residuum except a vap\r-l smoke1 & g5]ally )\t noise4 ,_! p>allax %[s !m to be v high 9 ! atmosph]e1 sometimes ev5 beyond its suppos$ limit1 & ! direction ( _! motion is = ! mo/ "p diametrically opposite to ! motion ( ! e>? 9 its orbit4 ,! a/oni%+ multitudes ( %oot+ />s & fire-balls t h appe>$ at /at$ p]iods ov] diff]5t p>ts ( ! globe1 w>rant ! conclusion t !re is ei!r a nebula or t !re are myriads ( bodies revolv+ 9 gr\ps r\nd ! sun :i* only become visible :5 inflam$ by ent]+ our atmosph]e4 ,"o ( ^! nebul or gr\ps seems to meet ! e>? 9 its annual revolution on ! #ab? & #ac? ( ,novemb]4 ,on ! morn+ ( ! #ab? ( ,novemb]1 #agii1 ?\s&s ( %oot+ />s1 mix$ ) l>ge meteors1 illum9at$ ! heav5s = _m h\rs ov] ! :ole cont95t ( ,am]ica1 f ,brazil to ,labrador3 x ext5d$ to ,gre5l&1 & ev5 ,g]many4 ,meteoric %[]s 7 se5 (f ! coa/ ( ,spa91 & 9 ! ,ohio c\ntry1 on ! morn+ ( ! #ac? ( ,novemb]1 #ahca2 & dur+ _m h\rs on ! morn+ ( ! #ac? ,novemb]1 #ahcb1 prodigi\s multitudes ( %oot+ />s & meteors fell at ,mo*a on ! ,r$ ,sea1 9 ! ,atlantic1 9 ,switz]l&1 & at _m places 9 ,engl&4 ,b by mu* ! mo/ spl5did meteoric %[] on record began at n9e o'clock 9 ! ev5+ ( ! #ab? ( ,novemb]1 #ahcc1 & la/$ till sunrise next morn+4 ,x ext5d$ f ,niag>a & ! nor!rn lakes ( ,am]ica to ! s\? ( ,jamaica1 & f #fa ( longitude 9 ! ,atlantic to #ajj ( longitude 9 c5tral ,mexico4 ,%oot+ />s & meteors1 ( ! app>5t size ( ,jupit]1 ,v5us1 & ev5 ! full moon1 d>t$ 9 myriads t[>ds ! horizon1 z if e /> 9 ! heav5s _h />t$ f _! sph]es4 ,!y are describ$ z hav+ be5 frequ5t z flakes ( sn[ 9 a sn[-/orm1 & to h be5 se5 ) equal brilliancy ov] ! great] "p ( ! cont95t ( ,nor? ,am]ica4 ,^? :o witness$ ?is gr& spectacle 7 surpris$ to see t e "o ( ! lum9\s bodies1 )\t exception1 mov$ 9 l9es :i* conv]g$ 9 "o po9t 9 ! heav5s3 none ( !m />t$ f t po9t2 b _! pa?s1 :5 trac$ backw>ds1 met 9 x l rays 9 a focus1 & ! mann] ( _! fall %[$ t !y desc5d$ f x 9 ne>ly p>allel /raight l9es t[>ds ! e>?4 ,by f> ! mo/ extraord9>y "p ( ! :ole ph5om5on is1 t ?is radiant po9t 0 obs]v$ to rema9 /ation>y ne> ! /> ,leonis = m ?an two h\rs & a half1 :i* prov$ ! s\rce ( ! meteoric %[] to be altoge!r indep5d5t ( ! e>?'s rotation1 & its p>allax %[$ x to be f> above ! atmosph]e4 ,z a body c\ld n be actually at re/ 9 t position1 ! gr\p or nebula mu/ ei!r h be5 mov+ r\nd ! e>? or ! sun4 ,_h x be5 mov+ ab\t ! e>?1 ! c\rse ( ! meteors w\ld h be5 tang5tial to its surface2 :]eas !y fell almo/ p]p5dicul>ly1 s t ! e>? 9 its annual revolution mu/ h met ) ! gr\p4 ,! bodies or ! p>ts ( ! nebula t 7 ne>e/ mu/ h be5 attract$ t[>ds ! e>? by its gravity1 &1 z !y 7 e/imat$ to move at ! rate ( f\rte5 miles 9 a second1 !y mu/ h tak5 fire on ent]+ our atmosph]e1 & be5 consum$ 9 _! passage ?r\gh x4 ,z all ! circum/ances ( ! ph5om5a 7 simil> on ! same day & dur+ ! same h\rs 9 #ahcb1 & z extraord9>y flights ( %oot+ />s 7 se5 at _m places bo? 9 ,europe & ,am]ica on ! #ac? ( ,novemb]1 #ahcd1 #ahce1 & #ahcf1 t5d+ also f a fix$ po9t 9 ! con/ellation ,leo1 x has be5 conjectur$1 ) mu* app>5t probability1 t ?is nebula or gr\p ( bodies p]=ms its revolution r\nd ! sun 9 a p]iod ( ab\t #ahb days1 9 an elliptical orbit1 ^: major axis is #aai millions ( miles2 & t its aphelion di/ance1 :]e x comes 9 contact ) ! e>?'s atmosph]e1 is ab\t #ie millions ( miles1 or ne>ly ! same ) ! mean di/ance ( ! e>? f ! sun4 ,?is body mu/ h met ) di/urbances aft] #agii1 :i* prev5t$ x f enc\nt]+ ! e>? = #cb ye>s1 & x may aga9 deviate f its pa? f ! same cause4 ,x is n[ well asc]ta9$ t great %[]s ( %oot+ />s occur also on ! #ab? ( ,augu/1 ^: po9t ( div]g5ce is ,camelop>dali1 s t ! e>?'s atmosph]e comes into contact ) a zone ( ^! small bodies twice 9 ! ye>4 ,by a sy/ematic s]ies ( obs]vations1 ,,mm4 ,b5z5b]g & ,br& h cle>ly made out t ! heights at :i* ! fall+ />s appe> & vani% v>y f #af miles to #adj1 & _! velocities f #ah to #cf miles 9 a second1 velocities s great z c]ta9ly to indicate a planet>y revolution r\nd ! sun4 ,z %oot+ />s are se5 almo/ e night :5 ! sky is cle>1 ,sir ,john ,lubbock has ?\ght x probable t "s ( ^! bodies may h come s ne>1 t ! attraction ( ! e>? has ov]come t ( ! sun1 & caus$ !m to revolve z satellites r\nd x4 ,%\ld t be ! case1 !y might %9e by ! reflect$ light ( ! sun1 & sudd5ly cease to be visible on ent]+ ! e>?'s %ad[4 ,! splitt+ ( ! fall+ />s l a rocket1 & ! tra9s ( light1 may be acc\nt$ = by suppos+ ! />s to graze ! surface ( ! %ad[ be=e be+ eclips$2 & ! disappe>ance w\ld be m or less rapid accord+ to ! bread? ( ! p5umbra trav]s$4 ,! calculations ( ,m4 ,petit1 ,director ( ! ,obs]vatory ( ,t\l\se1 n only r5d] probable ! exi/5ce ( small satellites1 b t5d to e/abli% ! id5tity ( a body revolv+ r\nd ! e>? 9 ?ree h\rs & tw5ty m9utes1 at a di/ance ( #ejjj miles above its surface4 ,x is evid5t t 9 ?is case ! same satellite w\ld be se5 v (t51 & a v few w\ld be suffici5t to acc\nt = _! nightly appe>ance4 ,x is possible1 h[ev]1 t "s %oot+ />s may belong to "o class1 & "s to ! o!r1 s9ce "o gr\p may be revolv+ ab\t ! sun1 & ano!r r\nd ! e>?4 ,9 ! case ( a satellite %oot+ />1 geometry furni%es ! means ( asc]ta9+ its exact di/ance f ! spectator1 or f ! c5tre ( ! e>?1 if ! "t & place ( its disappe>ance be kn[n ) reg>d to ! neighb\r+ />s4 ,s9ce ! fall+ />s are consum$ 9 ! atmosph]e1 _! masses mu/ be small1 b x is possible t occasionally "o may be l>ge en\gh to arrive at ! surface ( ! e>? z an arolite4 ,,section ,,xxxvii4 ,diffusion ( ,matt] ?r\gh ,space--,gravitation--,its ,velocity--,simplicity ( its ,laws--,gravitation indep5d5t ( ! ,magnitude & ,di/ances ( ! ,bodies--,n imp$$ by ! int]v5tion ( any ,sub/ance--,its ,int5sity inv>iable--,g5]al ,laws--,recapitulation & ,conclusion4 ,,! kn[n quantity ( matt] be>s a v small proportion to ! imm5sity ( space4 ,l>ge z ! bodies are1 ! di/ances :i* sep>ate !m are immeasurably great]2 b1 z design is manife/ 9 e "p ( creation1 x is probable t1 if ! v>i\s sy/ems 9 ! univ]se _h be5 ne>] to "o ano!r1 _! mutual di/urbances w\ld h be5 inconsi/5t ) ! h>mony & /ability ( ! :ole4 ,x is cle> t space is n p]vad$ by atmosph]ic air ( su* d5sity z t we brea!1 s9ce its resi/ance w\ld long ere ?is h arre/$ ! motion ( ! planets3 x c]ta9ly is n a void1 b replete ) a m$ium possibly 9 itself electric or magnetic1 b at all ev5ts capable ( transmitt+ light1 heat1 magnetism1 gravity1 & probably influ5ces ( :i* we c =m no idea4 ,:atev] ! laws may be t obta9 9 ! m di/ant regions ( creation1 we are assur$ t "o alone regulates ! motions1 n only ( our own sy/em1 b also ( ! b9>y sy/ems ( ! fix$ />s2 &1 z g5]al laws =m ! ultimate object ( philosophical rese>*1 we _c conclude ^! rem>ks )\t consid]+ ! nature ( gravitation--t extraord9>y p[] ^: effects we h be5 endeav\r+ to trace ?r\gh "s ( _! mazes4 ,x 0 at "o "t imag9$ t ! accel]ation 9 ! moon's mean motion 0 occasion$ by ! successive transmission ( ! gravitat+ =ce4 ,x has be5 prov$ t1 9 ord] to produce ?is effect1 its velocity mu/ be ab\t fifty millions ( times great] ?an t ( light1 :i* flies at ! rate ( #aib1jjj miles 9 a second4 ,its action1 ev5 at ! di/ance ( ! sun1 may !re=e be reg>d$ z in/antane\s2 yet1 remote z ! fix$ />s are1 ! sol> gravitation mu/ h "s influ5ce on ! ne>e/ ( !m1 z1 = example1 ,c5tauri1 :i* is only #bj1fjb times ! radius ( ! e>?'s orbit f ! sun1 :ile ,la ,place has comput$ t ! sol> gravitation ext5ds a hundr$ millions ( times f>!r ?an ! semidiamet] ( ! t]re/rial orbit4 ,possibly ! /> du/ 9 ! ,milky ,way may be beyond1 or on ! v]ge (1 t enorm\s limit2 yet x is v unlikely t ei!r ! sun1 or any ( ! />s :i* =m ! great clu/] to :i* we belong1 %\ld be unconnect$ bodies4 ,! curves 9 :i* ! cele/ial bodies move by ! =ce ( gravitation are only l9es ( ! second ord]4 ,! attraction ( sph]oids1 accord+ to any o!r law ( =ce ?an t ( gravitation1 w\ld be mu* m complicat$2 &1 z x is easy to prove t matt] might h be5 mov$ accord+ to an inf9ite v>iety ( laws1 x may be conclud$ t gravitation mu/ h be5 select$ by ,div9e ,wisdom out ( an inf9ity ( o!rs1 z be+ ! mo/ simple1 & t :i* gives ! greate/ /ability to ! cele/ial motions4 ,x is a s+ul> result ( ! simplicity ( ! laws ( nature1 :i* admit only ( ! obs]vation & comp>ison ( ratios1 t ! gravitation & !ory ( ! motions ( ! cele/ial bodies are indep5d5t ( _! absolute magnitudes & di/ances4 ,consequ5tly1 if all ! bodies ( ! sol> sy/em1 _! mutual di/ances1 & _! velocities1 7 to dim9i% proportionally1 !y w\ld describe curves 9 all respects simil> to ^? 9 :i* !y n[ move2 & ! sy/em might be successively r$uc$ to ! smalle/ s5sible dim5sions1 & /ill exhibit ! same appe>ances4 ,! action ( ! gravitat+ =ce is n imp$$ by ! int]v5tion ev5 ( ! d5se/ sub/ances4 ,if ! attraction ( ! sun = ! c5tre ( ! e>?1 & ( ! hemisph]e diametrically opposite to him1 7 dim9i%$ by a difficulty 9 p5etrat+ ! int]pos$ matt]1 ! tides w\ld be m obvi\sly affect$4 ,its attraction is ! same also1 :atev] ! sub/ances ( ! cele/ial bodies may be2 =1 if ! action ( ! sun ^u ! e>? diff]$ by a million? "p f 8 action ^u ! moon1 ! diff]5ce w\ld occasion a p]iodical v>iation 9 ! moon's p>allax1 ^: maximum w\ld be ! #a_/ae ( a second1 & also a v>iation 9 h] longitude am\nt+ to sev]al seconds--a supposition prov$ to be impossible by ! agreem5t ( !ory ) obs]vation4 ,?us all matt] is p]vi\s to gravitation1 & is equally attract$ by x4 ,gravitation is a feeble =ce1 va/ly inf]ior to electric action1 *emical aff9ity1 & cohesion2 yet1 z f> z human k ext5ds1 ! int5sity ( gravitation has nev] v>i$ )9 ! limits ( ! sol> sy/em2 nor does ev5 analogy lead u to expect t x %\ld3 on ! contr>y1 !re is e reason to be assur$ t ! great laws ( ! univ]se are immutable1 l _! ,au?or4 ,nor c we suppose ! /ructure ( ! globe alone to be exempt f ! univ]sal fiat ( g5]al laws1 ?\gh ages may pass be=e ! *anges x has und]gone1 or t are n[ 9 progress1 c be ref]r$ to exi/+ causes ) ! same c]ta9ty ) :i* ! motions ( ! planets1 & all _! p]iodic & secul> v>iations1 are ref]able to ! law ( gravitation4 ,! traces ( extreme antiquity p]petually occurr+ to ! geologi/ give t in=mation1 z to ! orig9 ( ?+s1 9 va9 look$ = 9 ! o!r p>ts ( ! univ]se4 ,!y date ! beg9n+ ( "t ) reg>d to our sy/em1 s9ce !re is gr\nd to believe t ! =mation ( ! e>? 0 contemporane\s ) t ( ! re/ ( ! planets2 b !y %[ t creation is ! "w ( ,him ) :om 8a ?\s& ye>s are z "o day1 & "o day z a ?\s& ye>s40 ,9 ! "w n[ br\ght to a conclusion1 x has be5 necess>y to select f ! :ole circle ( ! sci5ces a few ( ! mo/ obvi\s ( ^? proximate l9ks :i* connect !m toge!r1 & to pass ov] innum]able cases bo? ( evid5t & occult alliance4 ,any "o bran* trac$ ?r\gh its ramifications w\ld alone h occupi$ a volume2 x is hop$1 nev]!less1 t ! view "h giv5 w suffice to %[ ! ext5t to :i* a consid]ation ( ! reciprocal influ5ce ( ev5 a few ( ^! subjects may ultimately lead4 ,x ?us appe>s t ! !ory ( dynamics1 f\nd$ ^u t]re/rial ph5om5a1 is indisp5sable = acquir+ a k ( ! revolutions ( ! cele/ial bodies & _! reciprocal influ5ces4 ,! motions ( ! satellites are affect$ by ! =ms ( _! prim>ies1 & ! figures ( ! planets !mselves dep5d ^u _! rotations4 ,! symmetry ( _! int]nal /ructure proves ! /ability ( ^! rotatory motions1 & ! immutability ( ! l5g? ( ! day1 :i* furni%es an inv>iable /&>d ( "t2 & ! actual size ( ! t]re/rial sph]oid af=ds ! means ( asc]ta9+ ! dim5sions ( ! sol> sy/em1 & provides an inv>iable f\ndation = a sy/em ( weights & measures4 ,! mutual attraction ( ! cele/ial bodies di/urbs ! fluids at _! surfaces1 :5ce ! !ory ( ! tides & ( ! oscillations ( ! atmosph]e4 ,! d5sity & ela/icity ( ! air1 v>y+ ) e alt]nation ( temp]ature1 lead to ! consid]ation ( b>ometrical *anges1 ! measurem5t ( heights1 & capill>y attraction2 & ! doctr9e ( s\nd1 includ+ ! !ory ( music1 is to be ref]r$ to ! small undulations ( ! arial m$ium4 ,a k ( ! action ( matt] ^u light is requisite = trac+ ! curv$ pa? ( its rays ?r\gh ! atmosph]e1 by :i* ! true places ( di/ant objects are det]m9$1 :e!r 9 ! heav5s or on ! e>?4 ,by ?is we le>n ! nature & prop]ties ( ! sunbeam1 ! mode ( its propagation ?r\gh ! e!real m$ium1 or 9 ! int]ior ( mat]ial bodies1 & ! orig9 ( col\r4 ,by ! eclipses ( ,jupit]'s satellites ! velocity ( light is asc]ta9$2 & t velocity1 9 ! ab]ration ( ! fix$ />s1 furni%es a direct pro( ( ! real motion ( ! e>? 7,n4 #bcg74 ,! effects ( ! invisible rays ( ! spectrum are imm$iately connect$ ) *emical action2 & heat1 =m+ a "p ( ! sol> ray1 s ess5tial to animat$ & inanimat$ exi/5ce1 is too important an ag5t 9 ! economy ( creation n to hold a pr9cipal place 9 ! connexion ( physical sci5ces2 :5ce foll[s its di/ribution 9 ! int]ior & ov] ! surface ( ! globe1 its p[] on ! geological convulsions ( our planet1 its influ5ce on ! atmosph]e & on climate1 & its effects on vegetable & animal life1 ev9c$ 9 ! localities ( organiz$ be+s on ! e>?1 9 ! wat]s1 & 9 ! air4 ,! correlation betwe5 molecul> & *emical action1 light1 heat1 electricity1 & magnetism1 is cont9ually becom+ m p]fect1 & !re is e reason to believe t ^! diff]5t modes ( =ce1 z well z gravity itself1 w ultimately be f\nd to m]ge 9 "o great & univ]sal p[]4 ,_m m in/ances might be giv5 9 illu/ration ( ! imm$iate connexion ( ! physical sci5ces1 mo/ ( :i* are unit$ /ill m closely by ! common bond ( analysis1 :i* is daily ext5d+ its empire1 & w ultimately embrace almo/ e subject 9 nature 9 its =mul4 ,^! =mul1 emblematic ( ,omnisci5ce1 cond5se into a few symbols ! immutable laws ( ! univ]se4 ,?is mighty in/rum5t ( human p[] itself orig9ates 9 ! primitive con/itution ( ! human m9d1 & re/s ^u a few fundam5tal axioms1 :i* h et]nally exi/$ 9 ,him :o implant$ !m 9 ! brea/ ( man :5 ,he creat$ him aft] ,8 own image4 ,,notes4 ,,note #a1 page #b4 ,diamet]4 ,a /raight l9e pass+ ?r\gh ! c5tre1 & t]m9at$ bo? ways by ! sides or surface ( a figure1 su* z ( a circle or sph]e4 ,9 fig4 #a1 q ,q1 ,n ,s1 are diamet]s4 ,,note #b1 p4 #b4 ,ma!matical & me*anical sci5ces4 ,ma!matics tea* ! laws ( numb] & quantity2 me*anics treat ( ! equilibrium & motion ( bodies4 ,,note #c1 p4 #b4 ,analysis is a s]ies ( reason+ conduct$ by signs or symbols ( ! quantities ^: relations =m ! subject ( inquiry4 ,,note #d1 p4 #c4 ,oscillations are movem5ts to & fro1 l ! sw++ ( ! p5dulum ( a clock1 or waves 9 wat]4 ,! tides are oscillations ( ! sea4 ,,note #e1 p4 #c4 ,gravitation4 ,gravity is ! reciprocal attraction ( matt] on matt]2 gravitation is ! diff]5ce betwe5 gravity & ! c5trifugal =ce induc$ by ! velocity ( rotation or revolution4 ,s5sible gravity1 or weight1 is a p>ticul> in/ance ( gravitation4 ,x is ! =ce :i* causes sub/ances to fall to ! surface ( ! e>?1 & :i* reta9s ! cele/ial bodies 9 _! orbits4 ,its int5sity increases z ! squ>es ( ! di/ance decrease4 ,,note #f1 p4 #d4 ,p>ticles ( matt] are ! indef9itely small or ultimate atoms into :i* matt] is believ$ to be divisible4 ,_! =m is unkn[n2 b1 ?\gh too small to be visible1 !y mu/ h magnitude4 ,,note #g1 p4 #d4 ,a holl[ sph]e4 ,a holl[ ball1 l a bomb-%ell4 ,a sph]e is a ball or solid body1 su*1 t all l9es drawn f its c5tre to its surface are equal4 ,!y are call$ radii1 & e l9e pass+ ?r\gh ! c5tre & t]m9at$ bo? ways by ! surface is a diamet]1 :i* is consequ5tly equal to twice ! radius4 ,9 fig4 #c1 ,q q or ,n ,s is a diamet]1 & ,c ,q1 ,c ,n are radii4 ,a great circle ( ! sph]e has ! same c5tre ) ! sph]e z ! circles ,q ,e q d & ,q ,n q ,s4 ,! circle ,a ,b is a less] circle ( ! sph]e4 ,,note #h1 p4 #d4 ,conc5tric holl[ sph]es4 ,%ells1 or holl[ sph]es1 hav+ ! same c5tre1 l ! coats ( an onion4 ,illu/ration3 ,fig4 #a4 ,,note #i1 p4 #d4 ,sph]oid4 ,a solid body1 :i* sometimes has ! %ape ( an orange1 z 9 fig4 #a2 x is !n call$ an oblate sph]oid1 because x is flatt5$ at ! poles ,n & ,s4 ,su* is ! =m ( ! e>? & planets4 ,:51 on ! contr>y1 x is drawn out at ! poles l an egg1 z 9 fig4 #b1 x is call$ a prolate sph]oid4 ,x is evid5t t 9 bo? ^! solids ! radii ,c q1 ,c a1 ,c ,n1 c41 are g5]ally unequal2 :]eas 9 ! sph]e !y are all equal4 ,illu/ration3 ,fig4 #b4 ,,note #aj1 p4 #d4 ,c5tre ( gravity4 ,a po9t 9 e body1 :i* if support$1 ! body w rema9 at re/ 9 :atev] position x may be plac$4 ,ab\t t po9t all ! p>ts exactly balance "o ano!r4 ,! cele/ial bodies attract ea* o!r z if ea* 7 cond5s$ into a s+le p>ticle situate 9 ! c5tre ( gravity1 or ! p>ticle situate 9 ! c5tre ( gravity ( ea* may be reg>d$ z possess+ ! resultant p[] ( ! innum]able oblique =ces :i* con/itute ! :ole attraction ( ! body4 ,,note #aa1 pp4 #d1 #f4 ,poles & equator4 ,let fig4 #a or #c repres5t ! e>?1 ,c its c5tre1 ,n ,c ,s ! axis ( rotation1 or ! imag9>y l9e ab\t :i* x p]=ms its daily revolution4 ,!n ,n & ,s are ! nor? & s\? poles1 & ! great circle q ,e ,q1 :i* divides ! e>? into two equal p>ts1 is ! equator4 ,! e>? is flatt5$ at ! poles1 fig4 #a1 ! equatorial diamet]1 q ,q1 exce$+ ! pol> diamet]1 ,n ,s1 by ab\t #bf-a_/b miles4 ,less] circles1 ,a ,b ,g1 :i* are p>allel to ! equator1 are circles or p>allels ( latitude1 :i* is e/imat$ 9 degrees1 m9utes1 & seconds1 nor? & s\? ( ! equator1 e place 9 ! same p>allel hav+ ! same latitude4 ,gre5wi* is 9 ! p>allel ( #ea #bh #dj4 ,?us t]re/rial latitude is ! angul> di/ance betwe5 ! direction ( a plumb-l9e at any place & ! plane ( ! equator4 ,l9es su* z ,n ,q ,s1 ,n ,g ,e ,s1 fig4 #c1 are call$ m]idians2 all ! places 9 any "o ( ^! l9es h noon at ! same in/ant4 ,! m]idian ( ,gre5wi* has be5 *os5 by ! ,briti% z ! orig9 ( t]re/rial longitude1 :i* is e/imat$ 9 degrees1 m9utes1 & seconds1 ea/ & we/ ( t l9e4 ,if ,n ,g ,e ,s be ! m]idian ( ,gre5wi*1 ! position ( any place1 ,b1 is det]m9$1 :5 its latitude1 ,q ,c ,b1 & its longitude1 ,e ,c ,q1 are kn[n4 ,illu/ration3 ,fig4 #c4 ,,note #ab1 p4 #d4 ,mean quantities are su* z are int]m$iate betwe5 o!rs t are great] & less4 ,! mean ( any numb] ( unequal quantities is equal to _! sum divid$ by _! numb]4 ,= in/ance1 ! mean betwe5 two unequal quantities is equal to half _! sum4 ,,note #ac1 p4 #d4 ,a c]ta9 mean latitude4 ,! attraction ( a sph]e on an ext]nal body is ! same z if its mass 7 collect$ into "o heavy p>ticle 9 its c5tre ( gravity1 & ! int5sity ( its attraction dim9i%es z ! squ>e ( its di/ance f ! ext]nal body increases4 ,b ! attraction ( a sph]oid1 fig4 #a1 on an ext]nal body at m 9 ! plane ( its equator1 ,e ,q1 is great]1 & its attraction on ! same body :5 at m 9 ! axis ,n ,s less1 ?an if x 7 a sph]e4 ,!re=e1 9 bo? cases1 ! =ce deviates f ! exact law ( gravity4 ,?is deviation arises f ! protub]ant matt] at ! equator2 &1 z x dim9i%es t[>ds ! poles1 s does ! attractive =ce ( ! sph]oid4 ,b !re is "o mean latitude1 :]e ! attraction ( a sph]oid is ! same z if x 7 a sph]e4 ,x is a "p ( ! sph]oid int]m$iate betwe5 ! equator & ! pole4 ,9 t latitude ! squ>e ( ! s9e is equal to #a_/c ( ! equatorial radius4 ,,note #ad1 p4 #d4 ,mean di/ance4 ,! mean di/ance ( a planet f ! c5tre ( ! sun1 or ( a satellite f ! c5tre ( its planet1 is equal to half ! sum ( its greate/ & lea/ di/ances1 &1 consequ5tly1 is equal to half ! major axis ( its orbit4 ,= example1 let ,p ,q ,a ,d1 fig4 #f1 be ! orbit or pa? ( ! moon or ( a planet2 !n ,p ,a is ! major axis1 ,c ! c5tre1 & ,c ,s is equal to ,c ,f4 ,n[1 s9ce ! e>? or ! sun is suppos$ to be 9 ! po9t ,s accord+ z ,p ,d ,a ,q is reg>d$ z ! orbit ( ! moon or t ( a planet1 ,s ,a1 ,s ,p are ! greate/ & lea/ di/ances4 ,b half ! sum ( ,s ,a & ,s ,p is equal to half ( ,a ,p1 ! major axis ( ! orbit4 ,:5 ! body is at ,q or ,d1 x is at its mean di/ance f ,s1 = ,s ,q1 ,s ,d1 are ea* equal to ,c ,p1 half ! major axis by ! nature ( ! curve4 ,,note #ae1 p4 #d4 ,mean radius ( ! e>?4 ,! di/ance f ! c5tre to ! surface ( ! e>?1 reg>d$ z a sph]e4 ,x is int]m$iate betwe5 ! di/ances ( ! c5tre ( ! e>? f ! pole & f ! equator4 ,,note #af1 p4 #e4 ,ratio4 ,! relation :i* "o quantity be>s to ano!r4 ,,note #ag1 p4 #e4 ,squ>e ( moon's di/ance4 ,9 ord] to avoid l>ge numb]s1 ! mean radius ( ! e>? is tak5 = unity3 !n ! mean di/ance ( ! moon is express$ by #fj2 & ! squ>e ( t numb] is #cfjj1 or #fj times #fj4 ,illu/ration3 ,fig4 #d ,,note #ah1 p4 #e4 ,c5trifugal =ce4 ,! =ce ) :i* a revolv+ body t5ds to fly f ! c5tre ( motion3 a sl+ t5ds to fly f ! h& 9 consequ5ce ( ! c5trifugal =ce4 ,a tang5t is a /raight l9e t\*+ a curv$ l9e 9 "o po9t )\t cutt+ x1 z m ,t1 fig4 #d4 ,! direction ( ! c5trifugal =ce is 9 ! tang5t to ! curv$ l9e or pa? 9 :i* ! body revolves1 & its int5sity increases ) ! angul> sw+ ( ! body1 & ) its di/ance f ! c5tre ( motion4 ,z ! orbit ( ! moon does n diff] mu* f a circle1 let x be repres5t$ by m d g h1 fig4 #d1 ! e>? be+ 9 ,c4 ,! c5trifugal =ce aris+ f ! velocity ( ! moon 9 h] orbit balances ! attraction ( ! e>?4 ,by _! jo9t action1 ! moon moves ?r\gh ! arc m n dur+ ! "t t %e w\ld fly (f 9 ! tang5t m ,t by ! action ( ! c5trifugal =ce alone1 or fall ?r\gh m p by ! e>?'s attraction alone4 ,t n1 ! deflection f ! tang5t1 is p>allel & equal to m p1 ! v]s$ s9e ( ! arc m n1 suppos$ to be mov$ ov] by ! moon 9 a second1 & !re=e s v small t x may be reg>d$ z a /raight l9e4 ,t n1 or m p1 is ! space ! moon w\ld fall ?r\gh 9 ! fir/ second ( h] desc5t to ! e>?1 7 %e n reta9$ 9 h] orbit by h] c5trifugal =ce4 ,,note #ai1 p4 #e4 ,action & reaction4 ,:5 motion is communicat$ by collision or pressure1 ! action ( ! body :i* /rikes is return$ ) equal =ce by ! body :i* receives ! bl[4 ,! pressure ( a h& on a table is resi/$ ) an equal & contr>y =ce4 ,?is necess>ily foll[s f ! imp5etrability ( matt]1 a prop]ty by :i* no two p>ticles ( matt] c occupy ! same id5tical portion ( space at ! same "t4 ,:5 motion is communicat$ )\t app>5t contact1 z 9 gravitation1 attraction1 & repulsion1 ! quantity ( motion ga9$ by ! "o body is exactly equal to t lo/ by ! o!r1 b 9 a contr>y direction2 a circum/ance kn[n by exp]i5ce only4 ,,note #bj1 p4 #e4 ,project$4 ,a body is project$ :5 x is ?r[n3 a ball fir$ f a gun is project$2 x is !re=e call$ a projectile4 ,b ! ^w has also ano!r mean+4 ,a l9e1 surface1 or solid body1 is said to be project$ ^u a plane1 :5 p>allel /raight l9es are drawn f e po9t ( x to ! plane4 ,! figure s trac$ ^u a plane is a projection4 ,! projection ( a t]re/rial object is !re=e its daylight %ad[1 s9ce ! sun's rays are s5sibly p>allel4 ,,note #ba1 p4 #e4 ,space4 ,! b\ndless region :i* conta9s all creation4 ,illu/ration3 ,fig4 #e4 ,illu/ration3 ,fig4 #f4 ,,note #bb1 pp4 #e1 #aa4 ,conic sections4 ,l9es =m$ by any plane cutt+ a cone4 ,a cone is a solid figure1 l a sug>-loaf1 fig4 #e1 ( :i* ,a is ! apex1 ,a ,d ! axis1 & ! plane ,b ,e ,c ,f ! base4 ,! axis may or may n be p]p5dicul> to ! base1 & ! base may be a circle1 or any o!r curv$ l9e4 ,:5 ! axis is p]p5dicul> to ! base1 ! solid is a "r cone4 ,if a "r cone ) a circul> base be cut at "r angles to ! base by a plane pass+ ?r\gh ! apex1 ! section w be a triangle4 ,if ! cone be cut ?r\gh bo? sides by a plane p>allel to ! base1 ! section w be a circle4 ,if ! cone be cut slant+ q ?r\gh bo? sides1 ! section w be an ellipse1 fig4 #f4 ,if ! cone be cut p>allel to "o ( ! slop+ sides z ,a ,b1 ! section w be a p>abola1 fig4 #g4 ,& if ! plane cut only "o side ( ! cone1 & be n p>allel to ! o!r1 ! section w be a hyp]bola1 fig4 #h4 ,?us !re are five conic sections4 ,illu/ration3 ,fig4 #g4 ,illu/ration3 ,fig4 #h4 ,,note #bc1 p4 #e4 ,inv]se squ>e ( di/ance4 ,! attraction ( "o body = ano!r at ! di/ance ( two miles is f\r times less ?an at ! di/ance ( "o mile2 at ?ree miles1 x is n9e times less ?an at "o2 at f\r miles1 x is sixte5 times less1 & s on4 ,t is1 ! gravitat+ =ce decreases 9 int5sity z ! squ>es ( ! di/ance increase4 ,,note #bd1 p4 #e4 ,ellipse4 ,"o ( ! conic sections1 fig4 #f4 ,an ellipse may be drawn by fix+ ! ends ( a /r+ to two po9ts1 ,s & ,f1 9 a %eet ( pap]1 & !n c>ry+ ! po9t ( a p5cil r\nd 9 ! loop ( ! /r+ kept /ret*$1 ! l5g? ( ! /r+ be+ great] ?an ! di/ance betwe5 ! two po9ts4 ,! po9ts ,s & ,f are call$ ! foci1 ,c ! c5tre1 ,s ,c or ,c ,f ! exc5tricity1 ,a ,p ! major axis1 ,q ,d ! m9or axis1 & ,p ,s ! focal di/ance4 ,x is evid5t t1 ! less ! exc5tricity ,c ,s1 ! ne>] does ! ellipse approa* to a circle2 & f ! con/ruction x is cle> t ! l5g? ( ! /r+ ,s m ,f is equal to ! major axis ,p ,a4 ,if ,t t be a tang5t to ! ellipse at m1 !n ! angle ,t m ,s is equal to ! angle t m ,f2 &1 z ?is is true = e po9t 9 ! ellipse1 x foll[s t1 9 an elliptical reflect+ surface1 rays ( light or s\nd com+ f "o focus ,s w be reflect$ by ! surface to ! o!r focus ,f1 s9ce ! angle ( incid5ce is equal to ! angle ( reflection by ! !ories ( light & s\nd4 ,,note #be1 p4 #e4 ,p]iodic "t4 ,! "t 9 :i* a planet or comet p]=ms a revolution r\nd ! sun1 or a satellite ab\t its planet4 ,,note #bf1 p4 #e4 ,kepl] discov]$ ?ree laws 9 ! planet>y motions by :i* ! pr9ciple ( gravitation is e/abli%$3--#a/ law1 ,t ! radii vectores ( ! planets & comets describe areas proportional to ! "t4--,let fig4 #i be ! orbit ( a planet2 !n1 suppos+ ! spaces or areas ,p ,s p1 p ,s a1 a ,s b1 c41 equal to "o ano!r1 ! radius vector ,s ,p1 :i* is ! l9e jo9+ ! c5tres ( ! sun & planet1 passes ov] ^! equal spaces 9 equal times2 t is1 if ! l9e ,s ,p passes to ,s p 9 "o day1 x w come to ,s a 9 two days1 to ,s b 9 ?ree days1 & s on4 #bnd law1 ,t ! orbits or pa?s ( ! planets & comets are conic sections1 hav+ ! sun 9 "o ( _! foci4 ,! orbits ( ! planets & satellites are curves l fig4 #f or #i1 call$ ellipses1 hav+ ! sun 9 ! focus ,s4 ,sev]al comets are kn[n to move 9 ellipses2 b ! great] "p seem to move 9 p>abolas1 fig4 #g1 hav+ ! sun 9 ,s1 ?\gh x is probable t !y really move 9 v long flat ellipses2 o!rs appe> to move 9 hyp]bolas1 l fig4 #h4 ,! ?ird law is1 t ! squ>es ( ! p]iodic times ( ! planets are proportional to ! cubes ( _! mean di/ances f ! sun4 ,! squ>e ( a numb] is t numb] multipli$ by itself1 & ! cube ( a numb] is t numb] twice multipli$ by itself4 ,= example1 ! squ>es ( ! numb]s #b1 #c1 #d1 c41 are #d1 #i1 #af1 c41 b _! cubes are #h1 #bg1 #fd1 c4 ,!n ! squ>es ( ! numb]s repres5t+ ! p]iodic times ( two planets are to "o ano!r z ! cubes ( ! numb]s repres5t+ _! mean di/ances f ! sun4 ,s t1 ?ree ( ^! quantities be+ kn[n1 ! o!r may be f\nd by ! rule ( ?ree4 ,! mean di/ances are measur$ 9 miles or t]re/rial radii1 & ! p]iodic times are e/imat$ 9 ye>s1 days1 & p>ts ( a day4 ,kepl]'s laws ext5d to ! satellites4 ,illu/ration3 ,fig4 #i4 ,,note #bg1 p4 #e4 ,mass4 ,! quantity ( matt] 9 a giv5 bulk4 ,x is proportional to ! d5sity & volume or bulk conjo9tly4 ,,note #bh1 p4 #e4 ,gravitation proportional to mass4 ,b = ! resi/ance ( ! air1 all bodies w\ld fall to ! gr\nd 9 equal times4 ,9 fact1 a hundr$ equal p>ticles ( matt] at equal di/ances f ! surface ( ! e>? w\ld fall to ! gr\nd 9 p>allel /raight l9es ) equal rapidity1 & no *ange :atev] w\ld take place 9 ! circum/ances ( _! desc5t1 if #ii ( !m 7 unit$ 9 "o solid mass2 = ! solid mass & ! s+le p>ticle w\ld t\* ! gr\nd at ! same in/ant1 7 x n = ! resi/ance ( ! air4 ,,note #bi1 p4 #e4 ,prim>y signifies1 9 a/ronomy1 ! planet ab\t :i* a satellite revolves4 ,! e>? is prim>y to ! moon4 ,,note #cj1 p4 #f4 ,rotation4 ,motion r\nd an axis1 real or imag9>y4 ,,note #ca1 p4 #g4 ,compression ( a sph]oid4 ,! flatt5+ at ! poles4 ,x is equal to ! diff]5ce betwe5 ! greate/ & lea/ diamet]s1 divid$ by ! greate/1 ^! quantities be+ express$ 9 "s /&>d measure1 z miles4 ,,note #cb1 p4 #g4 ,,satellites4 ,small bodies revolv+ ab\t "s ( ! planets4 ,! moon is a satellite to ! e>?4 ,,note #cc1 p4 #g4 ,nutation4 ,a nodd+ motion 9 ! e>?'s axis :ile 9 rotation1 simil> to t obs]v$ 9 ! sp9n+ ( a top4 ,x is produc$ by ! attraction ( ! sun & moon on ! protub]ant matt] at ! t]re/rial equator4 ,,note #cd1 p4 #g4 ,axis ( rotation4 ,! l9e1 real or imag9>y1 ab\t :i* a body revolves4 ,! axis ( ! e>?'s rotation is t diamet]1 or imag9>y l9e1 pass+ ?r\gh ! c5tre & bo? poles4 ,fig4 #a be+ ! e>?1 ,n ,s is ! axis ( rotation4 ,,note #ce1 p4 #g4 ,nutation ( lun> orbit4 ,! action ( ! bulg+ matt] at ! e>?'s equator on ! moon occasions a v>iation 9 ! incl9ation ( ! lun> orbit to ! plane ( ! ecliptic4 ,suppose ! plane ,n p n1 fig4 #ac1 to be ! orbit ( ! moon1 & ,n m n ! plane ( ! ecliptic1 ! e>?'s action on ! moon causes ! angle p ,n m to become less or great] ?an its mean /ate4 ,! nutation 9 ! lun> orbit is ! reaction ( ! nutation 9 ! e>?'s axis4 ,,note #cf1 p4 #g4 ,translat$4 ,c>ri$ =w>d 9 space4 ,,note #cg1 p4 #g4 ,=ce proportional to velocity4 ,s9ce a =ce is measur$ by its effect1 ! motions ( ! bodies ( ! sol> sy/em among !mselves w\ld be ! same :e!r ! sy/em be at re/ or n4 ,! real motion ( a p]son walk+ ! deck ( a %ip at sea is comp\nd$ ( 8 own motion & t ( ! %ip1 yet ea* takes place indep5d5tly ( ! o!r4 ,we walk ab\t z if ! e>? 7 at re/1 ?\gh x has ! d\ble motion ( rotation on its axis & revolution r\nd ! sun4 ,,note #ch1 p4 #h4 ,tang5t4 ,a /raight l9e :i* t\*es a curv$ l9e 9 "o po9t )\t cutt+ x4 ,9 fig4 #d1 m ,t is tang5t to ! curve 9 ! po9t m4 ,9 a circle ! tang5t is at "r angles to ! radius1 ,c m4 ,,note #ci1 p4 #h4 ,motion 9 an elliptical orbit4 ,a planet m1 fig4 #f1 moves r\nd ! sun at ,s 9 an ellipse ,p ,d ,a ,q1 9 consequ5ce ( two =ces1 "o urg+ x 9 ! direction ( ! tang5t m ,t1 & ano!r pull+ x t[>ds ! sun 9 ! direction m ,s4 ,its velocity1 :i* is greate/ at ,p1 decreases ?r\gh\t ! arc to ,p ,d ,a to ,a1 :]e x is lea/1 & increases cont9ually z x moves along ! arc ,a ,q ,p till x comes to ,p aga94 ,! :ole =ce produc+ ! elliptical motion v>ies inv]sely z ! squ>e ( ! di/ance4 ,see note #bc4 ,,note #dj1 p4 #h4 ,radii vectores4 ,imag9>y l9es adjo9+ ! c5tre ( ! sun & ! c5tre ( a planet or comet1 or ! c5tres ( a planet & its satellite4 ,9 ! circle1 ! radii are all equal2 b 9 an ellipse1 fig4 #f1 ! radius vector ,s ,a is great]1 & ,s ,p less ?an all ! o!rs4 ,! radii vectores ,s ,q1 ,s ,d1 are equal to ,c ,a or ,c ,p1 half ! major axis ,p ,a1 & consequ5tly equal to ! mean di/ance4 ,a planet is at its mean di/ance f ! sun :5 9 ! po9ts ,q & ,d4 ,,note #da1 p4 #h4 ,equal areas 9 equal times4 ,see ,kepl]'s #a/ law1 9 note #bf1 p4 #e4 ,,note #db1 p4 #h4 ,major axis4 ,! l9e ,p ,a1 fig4 #f or #aj4 ,,note #dc1 p4 #h4 ,if ! planet describ$ a circle1 c4 ,! motion ( a planet ab\t ! sun1 9 a circle ,a ,b ,p1 fig4 #aj1 ^: radius ,c ,a is equal to ! planet's mean di/ance f him1 w\ld be equable1 t is1 its velocity1 or spe$1 w\ld always be ! same4 ,:]eas1 if x mov$ 9 ! ellipse ,a ,q ,p1 its spe$ w\ld be cont9ually v>y+1 by note #ci2 b its motion is su*1 t ! "t elaps+ betwe5 its dep>ture f ,p & its return to t po9t aga9 w\ld be ! same :e!r x mov$ 9 ! circle or 9 ! ellipse2 = ^! curves co9cide 9 ! po9ts ,p & ,a4 ,,note #dd1 p4 #h4 ,true motion4 ,! motion ( a body 9 its real orbit ,p ,d ,a ,q1 fig4 #aj4 ,illu/ration3 ,fig4 #aj4 ,,note #de1 p4 #i4 ,mean motion4 ,equable motion 9 a circle ,p ,e ,a ,b1 fig4 #aj1 at ! mean di/ance ,c ,p or ,c m1 9 ! "t t ! body w\ld accompli% a revolution 9 its elliptical orbit ,p ,d ,a ,q4 ,,note #df1 p4 #i4 ,! equ9ox4 ,fig4 #aa repres5ts ! cele/ial sph]e1 & ,c its c5tre1 :]e ! e>? is suppos$ to be4 q ,q is ! equ9octial or great circle1 trac$ 9 ! />ry heav5s by an imag9>y ext5sion ( ! plane ( ! t]re/rial equator1 & ,e e is ! ecliptic1 or app>5t pa? ( ! sun r\nd ! e>?4 1 ! int]section ( ^! two planes1 is ! l9e ( ! equ9oxes2 is ! v]nal equ9ox1 & ! autumnal4 ,:5 ! sun is 9 ^! po9ts1 ! days & nights are equal4 ,!y are di/ant f "o ano!r by a semicircle1 or two "r angles4 ,! po9ts ,e & e are ! sol/ices1 :]e ! sun is at 8 greate/ di/ance f ! equ9octial4 ,! equ9octial is ev]y:]e n9ety degrees di/ant f its poles ,n & ,s1 :i* are two po9ts diametrically opposite to "o ano!r1 :]e ! axis ( ! e>?'s rotation1 if prolong$1 w\ld meet ! heav5s4 ,! nor!rn cele/ial pole ,n is )9 #a #bd ( ! pole />4 ,z ! latitude ( any place on ! surface ( ! e>? is equal to ! height ( ! pole above ! horizon1 x is easily det]m9$ by obs]vation4 ,! ecliptic ,e e is also ev]y:]e n9ety degrees di/ant f its poles ,p & p4 ,! angle ,p ,c ,n1 betwe5 ! poles ,p & ,n ( ! equ9octial & ecliptic1 is equal to ! angle e ,c ,q1 call$ ! obliquity ( ! ecliptic4 ,illu/ration3 ,fig4 #aa4 ,,note #dg1 p4 #i4 ,longitude4 ,! v]nal equ9ox1 1 fig4 #aa1 is ! z]o po9t 9 ! heav5s :5ce cele/ial longitudes1 or ! angul> motions ( ! cele/ial bodies1 are e/imat$ f we/ to ea/1 ! direction 9 :i* !y all revolve4 ,! v]nal equ9ox is g5]ally call$ ! fir/ po9t ( ,aries1 ?\gh ^! two po9ts h n co9cid$ s9ce ! e>ly ages ( a/ronomy1 ab\t #bbcc ye>s ago1 on acc\nt ( a motion 9 ! equ9octial po9ts1 to be expla9$ h]eaft]4 ,if ,s 1 fig4 #aj1 be ! l9e ( ! equ9oxes1 & ! v]nal equ9ox1 ! true longitude ( a planet p is ! angle ,s p1 & its mean longitude is ! angle ,c m1 ! sun be+ 9 ,s4 ,cele/ial longitude is ! angul> di/ance ( a heav5ly body f ! v]nal equ9ox2 :]eas t]re/rial longitude is ! angul> di/ance ( a place on ! surface ( ! e>? f a m]idian arbitr>ily *os51 z t ( ,gre5wi*4 ,,note #dh1 pp4 #i1 #eh4 ,equation ( ! c5tre4 ,! diff]5ce betwe5 ,c m & ,s p1 fig4 #aj2 t is1 ! diff]5ce betwe5 ! true & mean longitudes ( a planet or satellite4 ,! true & mean places only co9cide 9 ! po9ts ,p & ,a2 9 e o!r po9t ( ! orbit1 ! true place is ei!r be=e or beh9d ! mean place4 ,9 mov+ f ,a ?r\gh ! arc ,a ,q ,p1 ! true place p is beh9d ! mean place m2 & ?r\gh ! arc ,p ,d ,a ! true place is be=e ! mean place4 ,at its maximum1 ! equation ( ! c5tre measures ,c ,s1 ! exc5tricity ( ! orbit1 s9ce x is ! diff]5ce betwe5 ! motion ( a body 9 an ellipse & 9 a circle ^: diamet] ,a ,p is ! major axis ( ! ellipse4 ,,note #di1 p4 #i4 ,apsides4 ,! po9ts ,p & ,a1 fig4 #aj1 at ! extremities ( ! major axis ( an orbit4 ,p is commonly call$ ! p]ihelion1 a ,greek t]m signify+ r\nd ! sun2 & ! po9t ,a is call$ ! aphelion1 a ,greek t]m signify+ at a di/ance f ! sun4 ,,note #ej1 p4 #i4 ,n9ety degrees4 ,a circle is divid$ into #cfj equal p>ts1 or degrees2 ea* degree into #fj equal p>ts1 call$ m9utes2 & ea* m9ute into #fj equal p>ts1 call$ seconds4 ,x is usual to write ^! quantities ?us1 #ae #af #aj1 :i* means fifte5 degrees1 sixte5 m9utes1 & t5 seconds4 ,x is cle> t an arc m n1 fig4 #d1 measures ! angle m ,c n2 h5ce we may say1 an arc ( s _m degrees1 or an angle ( s _m degrees2 =1 if !re be t5 degrees 9 ! angle m ,c n1 !re w be t5 degrees 9 ! arc m n4 ,x is evid5t t !re are #ij 9 a "r angle1 m ,c d1 or quadrant1 s9ce x is ! f\r? "p ( #cfj4 ,,note #ea1 p4 #i4 ,quadratures4 ,a cele/ial body is said to be 9 quadrature :5 x is #ij degrees di/ant f ! sun4 ,= example1 9 fig4 #ad1 if d be ! sun1 ,s ! e>?1 & p ! moon1 !n ! moon is said to be 9 quadrature :5 %e is 9 ei!r ( ! po9ts ,q or ,d1 because ! angles ,q ,s d & ,d ,s d1 :i* measure h] app>5t di/ance f ! sun1 are "r angles4 ,,note #eb1 p4 #i4 ,exc5tricity4 ,deviation f circul> =m4 ,9 fig4 #f1 ,c ,s is ! exc5tricity ( ! orbit ,p ,q ,a ,d4 ,! less ,c ,s1 ! m ne>ly does ! orbit or ellipse approa* ! circul> =m2 &1 :5 ,c ,s is z]o1 ! ellipse becomes a circle4 ,,note #ec1 p4 #i4 ,incl9ation ( an orbit4 ,let ,s1 fig4 #ab1 be ! c5tre ( ! sun1 ,p ,n ,a n ! orbit ( a planet mov+ f we/ to ea/ 9 ! direction ,n p4 ,let ,e ,n m e n be ! %ad[ or projection ( ! orbit on ! plane ( ! ecliptic1 !n ,n ,s n is ! int]section ( ^! two planes1 = ! orbit rises above ! plane ( ! ecliptic t[>ds ,n p1 & s9ks bel[ x at ,n ,p4 ,! angle p ,n m1 :i* ^! two planes make ) "o ano!r1 is ! incl9ation ( ! orbit ,p ,n p ,a to ! plane ( ! ecliptic4 ,,note #ed1 p4 #i4 ,latitude ( a planet4 ,! angle p ,s m1 fig4 #ab1 or ! height ( ! planet p above ! ecliptic ,e ,n m4 ,9 ?is case ! latitude is nor?4 ,?us1 cele/ial latitude is ! angul> di/ance ( a cele/ial body f ! plane ( ! ecliptic1 :]eas t]re/rial latitude is ! angul> di/ance ( a place on ! surface ( ! e>? f ! equator4 ,illu/ration3 ,fig4 #ab4 ,,note #ee1 p4 #i4 ,nodes4 ,! two po9ts ,n & n1 fig4 #ab1 9 :i* ! orbit ,n ,a n ,p ( a planet or comet int]sects ! plane ( ! ecliptic e ,n ,e n4 ,! "p ,n ,a n ( ! orbit lies above ! plane ( ! ecliptic1 & ! "p n ,p ,n bel[ x4 ,! asc5d+ node ,n is ! po9t ?r\gh :i* ! body passes 9 ris+ above ! plane ( ! ecliptic1 & ! desc5d+ node n is ! po9t 9 :i* ! body s9ks bel[ x4 ,! nodes ( a satellite's orbit are ! po9ts 9 :i* x int]sects ! plane ( ! orbit ( ! planet4 ,,note #ef1 p4 #aj4 ,di/ance f ! sun4 ,s p 9 fig4 #ab4 ,if be ! v]nal equ9ox1 !n ,s p is ! longitude ( ! planet p1 m ,s p is its latitude1 & ,s p its di/ance f ! sun4 ,:5 ^! ?ree quantities are kn[n1 ! place ( ! planet p is det]m9$ 9 space4 ,,note #eg1 pp4 #aj1 #ei4 ,elem5ts ( an orbit4 ,( ^! !re are sev54 ,let ,p ,n ,a n1 fig4 #ab1 be ! elliptical orbit ( a planet1 ,c its c5tre1 ,s ! sun 9 "o ( ! foci1 ! po9t ( ,aries1 & ,e ,n e n ! plane ( ! ecliptic4 ,! elem5ts are--! major axis ,a ,p2 ! exc5tricity ,c ,s2 ! p]iodic "t1 t is1 ! "t ( a complete revolution ( ! body 9 its orbit2 & ! f\r? is ! longitude ( ! body at any giv5 in/ant--= example1 t at :i* x passes ?r\gh ! p]ihelion ,p1 ! po9t ( its orbit ne>e/ to ! sun4 ,t in/ant is assum$ z ! orig9 ( "t1 :5ce all prec$+ & succe$+ p]iods are e/imat$4 ,^! f\r quantities are suffici5t to det]m9e ! =m ( ! orbit1 & ! motion ( ! body 9 x4 ,?ree o!r elem5ts are requisite = det]m9+ ! position ( ! orbit 9 space4 ,^! are1 ! angle ,s ,p1 ! longitude ( ! p]ihelion2 ! angle ,a ,n e1 :i* is ! incl9ation ( ! orbit to ! plane ( ! ecliptic2 &1 la/ly1 ! angle ,s ,n1 ! longitude ( ,n ! asc5d+ node4 ,,note #eh1 p4 #aj4 ,^: planes1 c4 ,! planes ( ! orbits1 z ,p ,n ,a n1 fig4 #ab1 9 :i* ! planets move1 are incl9$ or make small angles e ,n ,a ) ! plane ( ! ecliptic ,e ,n e n1 & cut x 9 /raight l9es1 ,n ,s n pass+ ?r\gh ,s1 ! c5tre ( ! sun4 ,,note #ei1 p4 #aa4 ,mom5tum4 ,=ce measur$ by ! weight ( a body & its spe$1 or simple velocity1 conjo9tly4 ,! primitive mom5tum ( ! planets is1 !re=e1 ! quantity ( motion :i* 0 impress$ ^u !m :5 !y 7 fir/ ?r[n into space4 ,,note #fj1 p4 #aa4 ,un/able equilibrium4 ,a body is said to be 9 equilibrium :5 x is s balanc$ z to rema9 at re/4 ,b !re are two k9ds ( equilibrium1 /able & un/able4 ,if a body balanc$ 9 /able equilibrium be slightly di/urb$1 x w endeav\r to return to re/ by a numb] ( movem5ts to & fro1 :i* w cont9ually decrease till !y cease altoge!r1 & !n ! body w be re/or$ to its orig9al /ate ( repose4 ,b1 if ! equilibrium be un/able1 ^! movem5ts to & fro1 or oscillations1 w become great] & great] till ! equilibrium is de/roy$4 ,,note #fa1 p4 #ad4 ,retrograde4 ,go+ backw>ds1 z f ea/ to we/1 contr>y to ! motion ( ! planets4 ,,note #fb1 p4 #ad4 ,p>allel directions4 ,su* z nev] meet1 ?\gh prolong$ ev] s f>4 ,illu/ration3 ,fig4 #ac4 ,illu/ration3 ,fig4 #ad4 ,,note #fc1 pp4 #ad1 #af4 ,! :ole =ce1 c4 ,let ,s1 fig4 #ac1 be ! sun1 ,n m n ! plane ( ! ecliptic1 p ! di/urb$ planet mov+ 9 its orbit n p ,n1 & d ! di/urb+ planet4 ,n[1 d attracts ! sun & ! planet p ) diff]5t int5sities 9 ! directions d ,s1 d p3 ! diff]5ce only ( ^! =ces di/urbs ! motion ( p2 x is !re=e call$ ! di/urb+ =ce4 ,b ?is :ole di/urb+ =ce may be reg>d$ z equival5t to ?ree =ces1 act+ 9 ! directions p ,s1 p ,t1 & p m4 ,! =ce act+ 9 ! radius vector p ,s1 jo9+ ! c5tres ( ! sun & planet1 is call$ ! radial =ce4 ,x sometimes draws ! di/urb$ planet p f ! sun1 & sometimes br+s x ne>] to him4 ,! =ce :i* acts 9 ! direction ( ! tang5t p ,t is call$ ! tang5tial =ce4 ,x di/urbs ! motion ( p 9 longitude1 t is1 x accel]ates its motion 9 "s p>ts ( its orbit & ret>ds x 9 o!rs1 s t ! radius vector ,s p does n move ov] equal areas 9 equal times4 7,see note #bf47 ,= example1 9 ! position ( ! bodies 9 fig4 #ad1 x is evid5t t1 9 consequ5ce ( ! attraction ( d1 ! planet p w h its motion accel]at$ f ,q to ,c1 ret>d$ f ,c to ,d1 aga9 accel]at$ f ,d to ,o1 & la/ly ret>d$ f ,o to ,q4 ,! di/urb+ body is "h suppos$ to be at re/1 & ! orbit circul>2 b1 z bo? bodies are p]petually mov+ ) diff]5t velocities 9 ellipses1 ! p]turbations or *anges 9 ! motions ( p are v num]\s4 ,la/ly1 t "p ( ! di/urb+ =ce :i* acts 9 ! direction ( a l9e p m1 fig4 #ac1 at "r angles to ! plane ( ! orbit ,n p n1 may be call$ ! p]p5dicul> =ce4 ,x sometimes causes ! body to approa* ne>]1 & sometimes to rec$e f>!r f1 ! plane ( ! ecliptic ,n m n1 ?an x w\ld o!rwise d4 ,! action ( ! di/urb+ =ces is admirably expla9$ 9 a "w on gravitation1 by ,mr4 ,airy1 ! ,a/ronom] ,royal4 ,,note #fd1 pp4 #af1 #gd4 ,p]ihelion4 ,fig4 #aj1 ,p1 ! po9t ( an orbit ne>e/ ! sun4 ,,note #fe1 p4 #af4 ,aphelion4 ,fig4 #aj1 ,a1 ! po9t ( an orbit f>!/ f ! sun4 ,,note #ff1 pp4 #af1 #ag4 ,9 fig4 #ae ! c5tral =ce is great] ?an ! exact law ( gravity2 !re=e ! curvature ,p p a is great] ?an ,p p ,a ! real ellipse2 h5ce ! planet p comes to ! po9t a1 call$ ! aphelion1 soon] ?an if x mov$ 9 ! orbit ,p p ,a1 :i* makes ! l9e ,p ,s ,a advance to a4 ,9 fig4 #af1 on ! contr>y1 ! curvature ,p p a is less ?an 9 ! true ellipse1 s t ! planet p mu/ move ?r\gh m ?an ! arc ,p p ,a1 or #ahj1 be=e x comes to ! aphelion a1 :i* causes ! great] axis ,p ,s ,a to rec$e to a4 ,illu/ration3 ,fig4 #ae4 ,illu/ration3 ,fig4 #af4 ,,note #fg1 pp4 #af1 #ag4 ,motion ( apsides4 ,let ,p ,s ,a1 fig4 #ag1 be ! position ( ! elliptical orbit ( a planet1 at any "t2 !n1 by ! action ( ! di/urb+ =ces1 x successively takes ! position ,p ,s ,a1 ,p ,s ,a1 c41 till by ?is direct motion x has accompli%$ a revolution1 & !n x beg9s aga92 s t ! motion is p]petual4 ,illu/ration3 ,fig4 #ag4 ,,note #fh1 p4 #ag4 ,sid]eal revolution4 ,! consecutive return ( an object to ! same />4 ,,note #fi1 p4 #ag4 ,tropical revolution4 ,! consecutive return ( an object to ! same tropic or equ9ox4 ,,note #gj1 p4 #ag4 ,! orbit only bulges1 c4 ,9 fig4 #ah ! effect ( ! v>iation 9 ! exc5tricity is %[n :]e ,p p ,a is ! elliptical orbit at any giv5 in/ant2 aft] a "t x w take ! =m ,p p ,a1 9 consequ5ce ( ! decrease 9 ! exc5tricity ,c ,s2 !n ! =ms ,p p ,a1 ,p p ,a1 c41 consecutively f ! same cause2 &1 z ! major axis ,p ,a always reta9s ! same l5g?1 ! orbit approa*es m & m ne>ly to ! circul> =m4 ,b1 aft] ?is has gone on = "s ?\s&s ( ye>s1 ! orbit contracts aga91 & becomes m & m elliptical4 ,illu/ration3 ,fig4 #ah4 ,,note #ga1 pp4 #ah1 #ai4 ,! ecliptic is ! app>5t pa? ( ! sun 9 ! heav5s4 ,see note #df4 ,,note #gb1 p4 #ah4 ,?is =ce t5ds to pull1 c4 ,! =ce 9 "q1 act+ 9 ! direction p m1 fig4 #ac1 pulls ! planet p t[>ds ! plane ,n m n1 or pu%es x f>!r above x1 giv+ ! planet a t5d5cy to move 9 an orbit above or bel[ its undi/urb$ orbit ,n p n1 :i* alt]s ! angle p ,n m1 & makes ! node ,n & ! l9e ( nodes ,n n *ange _! positions4 ,illu/ration3 ,fig4 #ai4 ,,note #gc1 p4 #ah4 ,motion ( ! nodes4 ,let ,s1 fig4 #ai1 be ! sun2 ,s ,n n ! plane ( ! ecliptic2 ,p ! di/urb+ body2 & p a planet mov+ 9 its orbit p n1 ( :i* p n is s small a "p t x is repres5t$ z a /raight l9e4 ,! plane ,s n p ( ?is orbit cuts ! plane ( ! ecliptic 9 ! /raight l9e ,s n4 ,suppose ! di/urb+ =ce beg9s to act on p1 s z to draw ! planet into ! arc p p2 !n1 in/ead ( mov+ 9 ! orbit p n1 x w t5d to move 9 ! orbit p p n1 ^: plane cuts ! ecliptic 9 ! /raight l9e ,s n4 ,if ! di/urb+ =ce acts aga9 ^u ! body :5 at p1 s z to draw x into ! arc p p1 ! planet w n[ t5d to move 9 ! orbit p p n1 ^: plane cuts ! ecliptic 9 ! /raight l9e ,s n4 ,! action ( ! di/urb+ =ce on ! planet :5 at p w br+ ! node to n1 & s on4 ,9 ?is mann] ! node goes backw>ds ?r\gh ! successive po9ts n1 n1 n1 n1 c41 & ! l9e ( nodes ,s n has a p]petual retrograde motion ab\t ,s1 ! c5tre ( ! sun4 ,! di/urb+ =ce has be5 repres5t$ z act+ at int]vals = ! sake ( illu/ration3 9 nature x is cont9u\s1 s t ! motion ( ! node is cont9u\s also2 ?\gh x is sometimes rapid & sometimes sl[1 n[ retrograde & n[ direct2 b1 on ! :ole1 ! motion is sl[ly retrograde4 ,,note #gd1 p4 #ah4 ,:5 ! di/urb+ planet is any:]e 9 ! l9e ,s ,n1 fig4 #ai1 or 9 its prolongation1 x is 9 ! same plane ) ! di/urb$ planet2 &1 h[ev] mu* x may affect its motions 9 t plane1 x c h no t5d5cy to draw x out ( x4 ,b :5 ! di/urb+ planet is 9 ,p1 at "r angles to ! l9e ,s ,n1 & n 9 ! plane ( ! orbit1 x has a p[]ful effect on ! motion ( ! nodes3 betwe5 ^! two positions !re is great v>iety ( action4 ,,note #ge1 p4 #ai4 ,! *anges 9 ! incl9ation are extremely m9ute :5 comp>$ ) ! motion ( ! node1 z evid5tly appe>s f fig4 #ai1 :]e ! angles n p n1 n p n1 c41 are mu* small] ?an ! correspond+ angles n ,s n1 ,s n1 c4 ,,note #gf1 p4 #bj4 ,s9es & cos9es4 ,figure #d is a circle2 n p is ! s9e1 & ,c p is ! cos9e ( an arc m n4 ,suppose ! radius ,c m to beg9 to revolve at m1 9 ! direction m n a2 !n at ! po9t m ! s9e is z]o1 & ! cos9e is equal to ! radius ,c m4 ,z ! l9e ,c m revolves & takes ! successive positions ,c n1 ,c a1 ,c b1 c41 ! s9es n p1 a q1 b r1 c41 ( ! arcs m n1 m a1 m h1 c41 increase1 :ile ! correspond+ cos9es ,c p1 ,c q1 ,c r1 c41 decrease2 & :5 ! revolv+ radius takes ! position ,c d1 at "r angles to ! diamet] g m1 ! s9e becomes equal to ! radius ,c d1 & ! cos9e is z]o4 ,aft] pass+ ! po9t d1 ! contr>y happ5s2 = ! s9es e ,k1 l ,v1 c41 dim9i%1 & ! cos9es ,c ,k1 ,c ,v1 c41 g on increas+1 till at g ! s9e is z]o1 & ! cos9e is equal to ! radius ,c g4 ,! same alt]nation takes place ?r\gh ! rema9+ p>ts g h1 h m1 ( ! circle1 s t a s9e or cos9e nev] c exce$ ! radius4 ,z ! rotation ( ! e>? is inv>iable1 ea* po9t ( its surface passes ?r\gh a complete circle1 or #cfj degrees1 9 tw5ty-f\r h\rs1 at a rate ( #ae degrees 9 an h\r4 ,"t1 !re=e1 becomes a measure ( angul> motion1 & vice v]s1 ! arcs ( a circle a measure ( "t1 s9ce ^! two quantities v>y simultane\sly & equably2 &1 z ! s9es & cos9es ( ! arcs are express$ 9 t]ms ( ! "t1 !y v>y ) x4 ,!re=e1 h[ev] long ! "t may be1 & h[ (t5 soev] ! radius may revolve r\nd ! circle1 ! s9es & cos9es nev] c exce$ ! radius2 &1 z ! radius is assum$ to be equal to unity1 _! values oscillate betwe5 unity & z]o4 ,,note #gg1 p4 #bj4 ,! small exc5tricities & incl9ations ( ! planet>y orbits1 & ! revolutions ( all ! bodies 9 ! same direction1 7 prov$ by ,eul]1 ,la ,grange1 & ,la ,place1 to be conditions necess>y = ! /ability ( ! sol> sy/em4 ,subsequ5tly1 h[ev]1 ! p]iodicity ( ! t]ms ( ! s]ies express+ ! p]turbations 0 suppos$ to be suffici5t alone1 b ,m4 ,poisson has %[n t to be a mi/ake2 t ^! ?ree conditions are requisite = ! necess>y conv]g5ce ( ! s]ies1 & t !re=e ! /ability ( ! sy/em dep5ds on !m conjo9tly ) ! p]iodicity ( ! s9es & cos9es ( ea* t]m4 ,! au?or is aw>e t ?is note c only be intelligible to ! analy/1 b %e is desir\s ( correct+ an error1 & ! m s z ! conditions ( /ability af=d "o ( ! mo/ /rik+ in/ances ( design 9 ! orig9al con/ruction ( our sy/em1 & ( ! =esight & supreme wisdom ( ! ,div9e ,ar*itect4 ,,note #gh1 p4 #bb4 ,resi/+ m$ium4 ,a fluid :i* resi/s ! motions ( bodies1 su* z atmosph]ic air1 or ! highly ela/ic fluid call$ e!r1 ) :i* space is fill$4 ,,note #gi1 p4 #bc4 ,obliquity ( ! ecliptic4 ,! angle e q1 fig4 #aa1 betwe5 ! plane ( ! t]re/rial equator q ,q1 & ! plane ( ! ecliptic ,e e4 ,! obliquity is v>iable4 ,,note #hj1 p4 #bc4 ,inv>iable plane4 ,9 ! e>? ! equator is ! inv>iable plane :i* ne>ly ma9ta9s a p>allel position ) reg>d to itself :ile revolv+ ab\t ! sun1 z 9 fig4 #bj1 :]e ,e ,q repres5ts x4 ,! two hemisph]es balance "o ano!r on ea* side ( ?is plane1 & w\ld /ill d s if all ! p>ticles ( :i* !y consi/ 7 moveable among !mselves1 provid$ ! e>? 7 n di/urb$ by ! action ( ! sun & moon1 :i* alt]s ! p>allelism ( ! equator by ! small v>iation call$ nutation1 to be expla9$ h]eaft]4 ,illu/ration3 ,fig4 #bj4 ,illu/ration3 ,fig4 #ba4 ,,note #ha1 p4 #bd4 ,if ea* p>ticle1 c4 ,let ,p1 ,p1 ,p1 c41 fig4 #ba1 be planets mov+ 9 _! orbits ab\t ! c5tre ( gravity ( ! sy/em4 ,let ,p ,s ,m1 ,p ,s ,m1 c41 be portions ( ^! orbits mov$ ov] by ! radii vectores ,s ,p1 ,s ,p1 c41 9 a giv5 "t1 & let p ,s m1 p ,s m1 c41 be _! %ad[s or projections on ! inv>iable plane4 ,!n1 if ! numb]s :i* repres5t ! masses ( ! planets ,p1 ,p1 c41 be respectively multipli$ by ! numb]s repres5t+ ! areas or spaces p ,s m1 p ,s m1 c41 ! sum ( ! :ole w be great] = ! inv>iable plane ?an x w\ld be = any plane t c\ld pass ?r\gh ,s1 ! c5tre ( gravity ( ! sy/em4 ,,note #hb1 p4 #bd4 ,! c5tre ( gravity ( ! sol> sy/em lies )9 ! body ( ! sun1 because 8 mass is mu* great] ?an ! masses ( all ! planets & satellites add$ toge!r4 ,,note #hc1 pp4 #be1 #cf4 ,conjunction4 ,a planet is said to be 9 conjunction :5 x has ! same longitude ) ! sun1 & 9 opposition :5 its longitude diff]s f t ( ! sun by #ahj degrees4 ,?us two bodies are said to be 9 conjunction :5 !y are se5 exactly 9 ! same "p ( ! heav5s1 & 9 opposition :5 diametrically opposite to "o ano!r4 ,m]cury & ,v5us1 :i* are ne>] to ! sun ?an ! e>?1 are call$ inf]ior planets2 :ile all ! o!rs1 be+ f>!r f ! sun ?an ! e>?1 are said to be sup]ior planets4 ,suppose ! e>? to be at ,e1 fig4 #bd2 !n a sup]ior planet w be 9 conjunction ) ! sun at ,c1 & 9 opposition to him :5 at ,o4 ,aga91 suppose ! e>? to be 9 ,o1 !n an inf]ior planet w be 9 conjunction :5 at ,e1 & 9 opposition :5 at ,f4 ,,note #hd1 p4 #bf4 ,! p]iodic inequalities are comput$ = a giv5 "t2 & consequ5tly = a giv5 =m & position ( ! orbits ( ! di/urb$ & di/urb+ bodies4 ,al?\gh ! elem5ts ( ! orbits v>y s sl[ly t no s5sible effect is produc$ on inequalities ( a %ort p]iod1 yet1 9 ! c\rse ( "t1 ! secul> v>iations ( ! elem5ts *ange ! =ms & relative positions ( ! orbits s mu*1 t ,jupit] & ,saturn1 :i* w\ld h come to ! same relative positions ) reg>d to ! sun & to "o ano!r aft] #hej ye>s1 d n arrive at ! same relative positions till aft] #iah ye>s4 ,,note #he1 p4 #bf4 ,configuration4 ,! relative position ( ! planets ) reg>d to "o ano!r1 to ! sun1 & to ! plane ( ! ecliptic4 ,,note #hf1 p4 #bg4 ,9 ! same mann] t ! exc5tricity ( an elliptical orbit may be increas$ or dim9i%$ by ! action ( ! di/urb+ =ces1 s a circul> orbit may acquire less or m ellipticity f ! same cause4 ,x is ?us t ! =ms ( ! orbits ( ! fir/ & second satellites ( ,jupit] oscillate betwe5 circles & ellipses diff]+ v little f circles4 ,illu/ration3 ,fig4 #bb4 ,,note #hg1 p4 #bh4 ,! plane ( ,jupit]'s equator is ! imag9>y plane pass+ ?r\gh 8 c5tre at "r angles to 8 axis ( rotation1 & corresponds to ! plane q ,e ,q e1 9 fig4 #a4 ,! satellites move v ne>ly 9 ! plane ( ,jupit]'s equator2 =1 if ,j be ,jupit]1 fig4 #bb1 ,p p 8 axis ( rotation1 e ,q 8 equatorial diamet]1 :i* is #fjjj miles long] ?an ,p p1 & if ,j ,o & ,j ,e be ! planes ( 8 orbit & equator se5 edgewise1 !n ! orbits ( 8 f\r satellites se5 edgewise w h ! positions ,j#a1 ,j#b1 ,j#c1 ,j#d4 ,^! are extremely ne> to "o ano!r1 = ! angle ,e ,j ,o is only #c #e #cj4 ,,note #hh1 p4 #bh4 ,9 consequ5ce ( ! satellites mov+ s ne>ly 9 ! plane ( ,jupit]'s equator1 :5 se5 f ! e>?1 !y appe> to be always v ne>ly 9 a /raight l9e1 h[ev] mu* !y may *ange _! positions ) reg>d to "o ano!r & to _! prim>y4 ,= example1 on ! ev5+s ( ! #crd1 #d?1 #e?1 & #f? ( ,janu>y1 #ahce1 ! satellites _h ! configurations giv5 9 fig4 #bc1 :]e ,o is ,jupit]1 & #a1 #b1 #c1 #d1 are ! fir/1 second1 ?ird1 & f\r? satellites4 ,! satellite is suppos$ to be mov+ 9 a direction f ! figure t[>ds ! po9t4 ,on ! six? ev5+ ! second satellite 0 se5 on ! disc ( ! planet4 ,illu/ration3 ,fig4 #bc4 ,,note #hi1 p4 #bh4 ,angul> motion or velocity is ! swiftness ) :i* a body revolves--a sl+1 = example2 or ! spe$ ) :i* ! surface ( ! e>? p]=ms its daily rotation ab\t its axis4 ,,note #ij1 p4 #bi4 ,displacem5t ( ,jupit]'s orbit4 ,! action ( ! planets occasions secul> v>iations 9 ! position ( ,jupit]'s orbit ,j ,o1 fig4 #bb1 )\t affect+ ! plane ( 8 equator ,j ,e4 ,aga91 ! sun & satellites !mselves1 by attract+ ! protub]ant matt] at ,jupit]'s equator1 *ange ! position ( ! plane ,j ,e )\t affect+ ,j ,o4 ,bo? ( ^! cause p]turbations 9 ! motions ( ! satellites4 ,,note #ia1 p4 #bi4 ,precession1 ) reg>d to ,jupit]1 is a retrograde motion ( ! po9t :]e ! l9es ,j ,o1 ,j ,e1 int]sect fig4 #bb4 ,,note #ib1 p4 #cj4 ,synodic motion ( a satellite4 ,its motion dur+ ! int]val betwe5 two ( its consecutive eclipses4 ,illu/ration3 ,fig4 #bd4 ,,note #ic1 p4 #cj4 ,opposition4 ,a body is said to be 9 opposition :5 its longitude diff]s f t ( ! sun by #ahj4 ,if ,s1 fig4 #bd1 be ! sun1 & ,e ! e>?1 !n ,jupit] is 9 opposition :5 at ,o1 & 9 conjunction :5 at ,c4 ,9 ^! positions ! ?ree bodies are 9 ! same /raight l9e4 ,,note #id1 p4 #cj4 ,eclipses ( ! satellites4 ,let ,s1 fig4 #be1 be ! sun1 ,j ,jupit]1 & a ,b b 8 %ad[4 ,let ! e>? be mov+ 9 its orbit1 9 ! direction ,e ,a ,r ,t ,h1 & ! ?ird satellite 9 ! direction a b m n4 ,:5 ! e>? is at ,e1 ! satellite1 9 mov+ ?r\gh ! arc a b1 w vani% at a1 & reappe> at b1 on ! same side ( ,jupit]4 ,if ! e>? be 9 ,r1 ,jupit] w be 9 opposition2 & !n ! satellite1 9 mov+ ?r\gh ! arc a b1 w vani% close to ! disc ( ! planet1 & w reappe> on ! o!r side ( x4 ,b1 if ! satellite be mov+ ?r\gh ! arc m n1 x w appe> to pass ov] ! disc1 & eclipse ! planet4 ,illu/ration3 ,fig4 #be4 ,,note #ie1 pp4 #cj1 #dc4 ,m]idian4 ,a t]re/rial m]idian is a l9e pass+ r\nd ! e>? & ?r\gh bo? poles4 ,9 e "p ( x noon happ5s at ! same in/ant4 ,9 figures #a & #c1 ! l9es ,n ,q ,s & ,n ,g ,s are m]idians1 ,c be+ ! c5tre ( ! e>?1 & ,n ,s its axis ( rotation4 ,! m]idian pass+ ?r\gh ! ,obs]vatory at ,gre5wi* is assum$ by ! ,briti% z a fix$ orig9 f :5ce t]re/rial longitudes are measur$4 ,& z ea* po9t on ! surface ( ! e>? passes ?r\gh #cfj1 or a complete circle1 9 tw5ty-f\r h\rs1 at ! rate ( #ae 9 an h\r1 "t becomes a repres5tative ( angul> motion4 ,h5ce1 if ! eclipse ( a satellite happ5s at any place at eight o'clock 9 ! ev5+1 & ! ,nautical ,almanac %[s t ! same ph5om5on w take place at ,gre5wi* at n9e1 ! place ( obs]vation w be 9 ! #ae ( we/ longitude4 ,,note #if1 p4 #ca4 ,conjunction4 ,let ,s be ! sun1 fig4 #bd1 ,e ! e>?1 & ,j ,o ,j ,c ! orbit ( ,jupit]4 ,!n ! eclipses :i* happ5 :5 ,jupit] is 9 ,o are se5 #afm #bfs soon] ?an ^? :i* take place :5 ! planet is 9 ,c4 ,jupit] is 9 conjunction :5 at ,c1 & 9 opposition :5 9 ,o4 ,illu/ration3 ,fig4 #bf4 ,,note #ig1 p4 #ca4 ,9 ! diagonal1 c4 ,7 ! l9e ,a ,s1 fig4 #bf1 #ajj1jjj times long] ?an ,a ,b1 ,jupit]'s true place w\ld be 9 ! direction ,a ,s1 ! diagonal ( ! figure ,a ,b ,s ,s1 :i* is1 ( c\rse1 out ( proportion4 ,,note #ih1 p4 #ca4 ,ab]ration ( light4 ,! cele/ial bodies are s di/ant t ! rays ( light com+ f !m may be reckon$ p>allel4 ,!re=e1 let ,s ,a1 ,s ,b1 fig4 #bf1 be two rays ( light com+ f ! sun1 or a planet1 to ! e>? mov+ 9 its orbit 9 ! direction ,a ,b4 ,if a telescope be held 9 ! direction ,a ,s1 ! ray ,s ,a1 in/ead ( go+ d[n ! tube1 w imp+e on its side1 & be lo/ 9 consequ5ce ( ! telescope be+ c>ri$ ) ! e>? 9 ! direction ,a ,b4 ,b1 if ! tube be held 9 ! position ,a ,e1 s t ,a ,b is to ,a ,s z ! velocity ( ! e>? to ! velocity ( light1 ! ray w pass ?r\gh ,s ,e ,a4 ,! /> appe>s to be 9 ! direction ,a ,s1 :5 x really is 9 ! direction ,a ,s2 h5ce ! angle ,s ,a ,s is ! angle ( ab]ration4 ,,note #ii1 p4 #cb4 ,d5sity proportional to ela/icity4 ,! m a fluid1 su* z atmosph]ic air1 is r$uc$ 9 dim5sions by pressure1 ! m x resi/s ! pressure4 ,,note #ajj1 p4 #cb4 ,oscillations ( p5dulum ret>d$4 ,if a clock be c>ri$ f ! pole to ! equator1 its rate w be gradually dim9i%$1 t is1 x w g sl[] & sl[]3 because ! c5trifugal =ce1 :i* increases f ! pole to ! equator1 dim9i%es ! =ce ( gravity4 ,,note #aja1 p4 #cd4 ,di/urb+ action4 ,! di/urb+ =ce acts "h 9 ! v same mann] z 9 note #fc2 only t ! di/urb+ body d1 fig4 #ad1 is ! sun1 ,s ! e>?1 & p ! moon4 ,,note #ajb1 pp4 #ce1 #cf1 #hf4 ,p]igee4 ,a ,greek ^w1 signify+ r\nd ! e>?4 ,! p]igee ( ! lun> orbit is ! po9t ,p1 fig4 #f1 :]e ! moon is ne>e/ to ! e>?4 ,x corresponds to ! p]ihelion ( a planet4 ,sometimes ! ^w is us$ to d5ote ! po9t :]e ! sun is ne>e/ to ! e>?4 ,,note #ajc1 p4 #ce4 ,evection4 ,! evection is produc$ by ! action ( ! radial =ce 9 ! direction ,s p1 fig4 #ad1 :i* sometimes increases & sometimes dim9i%es ! e>?'s attraction to ! moon4 ,x produces a correspond+ tempor>y *ange 9 ! exc5tricity1 :i* v>ies ) ! position ( ! major axis ( ! lun> orbit 9 respect ( ! l9e ,s d1 jo9+ ! c5tres ( ! e>? & sun4 ,,note #ajd1 p4 #ce4 ,v>iation4 ,! lun> p]turbation call$ ! v>iation is ! alt]nate accel]ation & ret>dation ( ! moon 9 longitude1 f ! action ( ! tang5tial =ce4 ,%e is accel]at$ 9 go+ f quadratures 9 ,q & ,d1 fig4 #ad1 to ! po9ts ,c & ,o1 call$ syzygies1 & is ret>d$ 9 go+ f ! syzygies ,c & ,o to ,q & ,d aga94 ,,note #aje1 p4 #cf4 ,squ>e ( "t4 ,if ! times increase at ! rate ( #a1 #b1 #c1 #d1 c41 ye>s or hundr$s ( ye>s1 ! squ>es ( ! times w be #a1 #d1 #i1 #af1 c41 ye>s or hundr$s ( ye>s4 ,,note #ajf1 p4 #cg4 ,9 all inve/igations hi!rto made ) reg>d to ! accel]ation1 x 0 tacitly assum$ t ! areas describ$ by ! radius vector ( ! moon 7 n p]man5tly alt]$2 t is to say1 t ! tang5tial di/urb+ =ce produc$ no p]man5t effect4 ,b ,mr4 ,adams has discov]$ t1 9 consequ5ce ( ! con/ant decrease 9 ! exc5tricity ( ! e>?'s orbit1 !re is a gradual *ange 9 ! c5tral di/urb+ =ce :i* affects ! arial velocity1 & consequ5tly x alt]s ! am\nt ( ! accel]ation by a v small quantity1 z well z ! v>iation & o!r p]iodical inequalities ( ! moon4 ,on ! latt]1 h[ev]1 x has no p]man5t effect1 because x affects !m 9 opposite directions 9 v mod]ate int]vals ( "t1 :]eas a v small error 9 ! am\nt ( ! accel]ation goes on increas+ z long z ! exc5tricity ( ! e>?'s orbit dim9i%es1 s t x w\ld ultimately vitiate calculations ( ! moon's place = di/ant p]iods ( "t4 ,?is %[s h[ complicat$ ! moon's motions are1 & :at rigor\s accuracy is requir$ 9 _! det]m9ation4 ,to give an idea ( ! lab\r requisite m]ely to p]fect or correct ! lun> tables1 ! moon's place 0 det]m9$ by obs]vation at ! ,gre5wi* ,obs]vatory 9 #fjjj diff]5t po9ts ( h] orbit1 ea* ( :i* 0 comp>$ ) ! same po9ts calculat$ f ,b>on ,plana's =mul1 & to d t sixte5 comput]s 7 con/antly employ$ = eight ye>s4 ,s9ce ! longitude is det]m9$ by ! motions ( ! moon1 ! lun> tables are ( ! greate/ importance4 ,,note #ajg1 p4 #cg4 ,mean anomaly4 ,! mean anomaly ( a planet is its angul> di/ance f ! p]ihelion1 suppos+ x to move 9 a circle4 ,! true anomaly is its angul> di/ance f ! p]ihelion 9 its elliptical orbit4 ,= example1 9 fig4 #aj1 ! mean anomaly is ,p ,c m1 & ! true anomaly is ,p ,s p4 ,,note #ajh1 pp4 #ch1 #fh4 ,_m circumf]5ces4 ,!re are #cfj degrees or #a1bif1jjj seconds 9 a circumf]5ce2 &1 z ! accel]ation ( ! moon only increases at ! rate ( elev5 seconds 9 a c5tury1 x mu/ be a prodigi\s numb] ( ages be=e x accumulates to _m circumf]5ces4 ,,note #aji1 p4 #ci4 ,phases ( ! moon4 ,! p]iodical *anges 9 ! enlight5$ "p ( h] disc1 f a cresc5t to a circle1 dep5d+ ^u h] position ) reg>d to ! sun & e>?4 ,,note #aaj1 p4 #ci4 ,lun> eclipse4 ,let ,s1 fig4 #bg1 be ! sun1 ,e ! e>?1 & m ! moon4 ,! space a ,a b is a section ( ! %ad[1 :i* has ! =m ( a cone or sug>-loaf1 & ! spaces ,a a c1 ,a b d1 are ! p5umbra4 ,! axis ( ! cone passes ?r\gh ,a1 & ?r\gh ,e & ,s1 ! c5tres ( ! sun & e>?1 & n m n is ! pa? ( ! moon ?r\gh ! %ad[4 ,illu/ration3 ,fig4 #bg4 ,,note #aaa1 p4 #ci4 ,app>5t diamet]4 ,! diamet] ( a cele/ial body z se5 f ! e>?4 ,,note #aab1 p4 #dj4 ,p5umbra4 ,! %ad[ or imp]fect d>kness :i* prec$es & foll[s an eclipse4 ,,note #aac1 p4 #dj4 ,synodic revolution ( ! moon4 ,! "t betwe5 two consecutive new or full moons4 ,,note #aad1 p4 #dj4 ,horizontal refraction4 ,! light1 9 com+ f a cele/ial object1 is b5t into a curve z soon z x ent]s our atmosph]e2 & t b5d+ is greate/ :5 ! object is 9 ! horizon4 ,illu/ration3 ,fig4 #bh4 ,,note #aae1 p4 #dj4 ,sol> eclipse4 ,let ,s1 fig4 #bh1 be ! sun1 m ! moon1 & ,e ! e>?4 ,!n a ,e b is ! moon's %ad[1 :i* sometimes eclipses a small portion ( ! e>?'s surface at e1 & sometimes falls %ort ( x4 ,to a p]son at e1 9 ! c5tre ( ! %ad[1 ! eclipse may be total or annul>2 to a p]son n 9 ! c5tre ( ! %ad[ a "p ( ! sun w be eclips$2 & to "o at ! edge ( ! %ad[ !re w be no eclipse at all4 ,! spaces ,p b ,e1 ,p a ,e1 are ! p5umbra4 ,,note #aaf1 p4 #dc4 ,f ! extremities1 c4 ,if ! l5g? ( ! l9e a b1 fig4 #bi1 be measur$1 9 feet or fa?oms1 ! angles ,s b a1 ,s a b1 c be measur$1 & !n ! angle a ,s b is kn[n1 :5ce ! l5g? ( ! l9e ,s ,c may be comput$4 a ,s b is ! p>allax ( ! object ,s2 & x is cle> t1 ! great] ! di/ance ( ,s1 ! less ! base a b w appe>1 because ! angle a ,s b is less ?an a ,s b4 ,illu/ration3 ,fig4 #bi4 ,,note #aag1 p4 #dd4 ,e p>ticle w describe a circle1 c4 ,if ,n ,s1 fig4 #c1 be ! axis ab\t :i* ! body revolves1 !n p>ticles at ,b1 ,q1 c41 w :irl 9 ! circles ,b ,g ,a a1 ,q ,e q d1 ^: c5tres are 9 ! axis ,n ,s1 & _! planes p>allel to "o ano!r4 ,!y are1 9 fact1 p>allels ( latitude1 ,q ,e q d be+ ! equator4 ,,note #aah1 p4 #dd4 ,! =ce ( gravity1 c4 ,gravity at ! equator acts 9 ! direction ,q ,c1 fig4 #cj4 ,:]eas ! direction ( ! c5trifugal =ce is exactly contr>y1 be+ 9 ! direction ,c ,q2 h5ce ! diff]5ce ( ! two is ! =ce call$ gravitation1 :i* makes bodies fall to ! surface ( ! e>?4 ,at any po9t1 m1 n at ! equator1 ! direction ( gravity is m b1 p]p5dicul> to ! surface1 b ! c5trifugal =ce acts p]p5dicul>ly to ,n ,s1 ! axis ( rotation4 ,n[ ! effect ( ! c5trifugal =ce is ! same z if x 7 two =ces1 "o ( :i* act+ 9 ! direction b m1 dim9i%es ! =ce ( gravity1 & ano!r :i*1 act+ 9 ! direction m t1 tang5t to ! surface at m1 urges ! p>ticles t[>ds ,q1 & t5ds to swell out ! e>? at ! equator4 ,illu/ration3 ,fig4 #cj4 ,,note #aai1 p4 #de4 ,homog5e\s mass4 ,a quantity ( matt]1 ev]y:]e ( ! same d5sity4 ,,note #abj1 p4 #de4 ,ellipsoid ( revolution4 ,a solid =m$ by ! revolution ( an ellipse ab\t its axis4 ,if ! ellipse revolve ab\t its m9or axis ,q ,d1 fig4 #f1 ! ellipsoid w be oblate1 or flatt5$ at ! poles l an orange4 ,if ! revolution be ab\t ! great] axis ,a ,p1 ! ellipsoid w be prolate1 l an egg4 ,,note #aba1 p4 #de4 ,conc5tric elliptical /rata4 ,/rata1 or lay]s1 hav+ an elliptical =m & ! same c5tre4 ,,note #abb1 p4 #df4 ,on ! :ole1 c4 ,! l9e ,n ,q ,s q1 fig4 #a1 repres5ts ! ellipse 9 "q1 its major axis be+ ,q q1 its m9or axis ,n ,s4 ,,note #abc1 p4 #df4 ,increase 9 ! l5g? ( ! radii1 c4 ,! radii gradually increase f ! pol> radius ,c ,n1 fig4 #cj1 :i* is lea/1 to ! equatorial radius ,c ,q1 :i* is greate/4 ,!re is also an increase 9 ! l5g?s ( ! arcs correspond+ to ! same numb] ( degrees f ! equator to ! poles2 =1 ! angle ,n ,c r be+ equal to q ,c d1 ! elliptical arc ,n r is less ?an q d4 ,,note #abd1 p4 #df4 ,cos9e ( latitude4 ,! angles m ,c a1 m ,c b1 fig4 #d1 be+ ! latitudes ( ! po9ts a1 b1 c41 ! cos9es are ,c q1 ,c r1 c4 ,,note #abe1 p4 #dg4 ,an arc ( ! m]idian4 ,let ,n ,q ,s q1 fig4 #cj1 be ! m]idian1 & m n ! arc to be measur$4 ,!n1 if ,z m1 ,z n1 be v]ticals1 or l9es p]p5dicul> to ! surface ( ! e>?1 at ! extremities ( ! arc m n !y w meet 9 p4 ,q a n1 ,q b m1 are ! latitudes ( ! po9ts m & n1 & _! diff]5ce is ! angle m p n4 ,s9ce ! latitudes are equal to ! height ( ! pole ( ! equ9octial above ! horizon ( ! places m & n1 ! angle m p n may be f\nd by obs]vation4 ,:5 ! di/ance m n is measur$ 9 feet or fa?oms1 & divid$ by ! numb] ( degrees & p>ts ( a degree conta9$ 9 ! angle m p n1 ! l5g? ( an arc ( "o degree is obta9$4 ,,note #abf1 p4 #dg4 ,a s]ies ( triangles4 ,let ,m ,m1 fig4 #ca1 be ! m]idian ( any place4 ,a l9e ,a ,b is measur$ ) rods1 on level gr\nd1 ( any numb] ( fa?oms1 ,c be+ "s po9t se5 f bo? ends ( x4 ,z two ( ! angles ( ! triangle ,a ,b ,c c be measur$1 ! l5g?s ( ! sides ,a ,c1 ,b ,c1 c be comput$2 & if ! angle m ,a ,b1 :i* ! base ,a ,b makes ) ! m]idian1 be measur$1 ! l5g? ( ! sides ,b m1 ,a m1 may be obta9$ by computation1 s t ,a m1 a small "p ( ! m]idian1 is det]m9$4 ,aga91 if ,d be a po9t visible f ! extremities ( ! kn[n l9e ,b ,c1 two ( ! angles ( ! triangle ,b ,c ,d may be measur$1 & ! l5g? ( ! sides ,c ,d1 ,b ,d1 comput$4 ,!n1 if ! angle ,b m m be measur$1 all ! angles & ! side ,b m ( ! triangle ,b m m are kn[n1 :5ce ! l5g? ( ! l9e m m may be comput$1 s t ! portion ,a m ( ! m]idian is det]m9$1 & 9 ! same mann] x may be prolong$ indef9itely4 ,illu/ration3 ,fig4 #ca4 ,,note #abg1 pp4 #dg1 #di4 ,! squ>e ( ! s9e ( ! latitude4 ,q b m1 fig4 #cj1 be+ ! latitude ( m1 e m is ! s9e & b e ! cos9e4 ,!n ! numb] express+ ! l5g? ( e m1 multipli$ by itself1 is ! squ>e ( ! s9e ( ! latitude2 & ! numb] express+ ! l5g? ( b e1 multipli$ by itself1 is ! squ>e ( ! cos9e ( ! latitude4 ,,note #abh1 p4 #dh4 ,! pol> diamet] ( ! e>? det]m9$ by ! survey ( ,great ,brita9 is #gijj miles2 ! equatorial is #gibf1 :i* gives a compression ( #a_/biicc4 ,,note #abi1 p4 #ej4 ,a p5dulum is t "p ( a clock :i* sw+s to & fro4 ,illu/ration3 ,fig4 #cb4 ,,note #acj1 p4 #eb4 ,p>allax4 ,! angle a ,s b1 fig4 #bi1 "u :i* we view an object a b3 x !re=e dim9i%es z ! di/ance increases4 ,! p>allax ( a cele/ial object is ! angle :i* ! radius ( ! e>? w\ld be se5 "u1 if view$ f t object4 ,let ,e1 fig4 #cb1 be ! c5tre ( ! e>?1 ,e ,h its radius1 & m ,h ,o ! horizon ( an obs]v] at ,h4 ,!n ,h m ,e is ! p>allax ( a body m1 ! moon = example4 ,z m rises high] & high] 9 ! heav5s to ! po9ts m1 m1 c41 ! p>allax ,h m ,e1 ,h m ,e1 c41 decreases4 ,at ,z1 ! z5i?1 or po9t imm$iately above ! head ( ! obs]v]1 x is z]o2 & at m1 :]e ! body is 9 ! horizon1 ! angle ,h m ,e is ! greate/ possible1 & is call$ ! horizontal p>allax4 ,x is cle> t ) reg>d to cele/ial bodies ! :ole effect ( p>allax is 9 ! v]tical1 or 9 ! direction m m ,z2 & z a p]son at ,h sees m 9 ! direction ,h m ,a1 :5 x really is 9 ! direction ,e m ,b1 x makes cele/ial objects appe> to be l[] ?an !y really are4 ,! di/ance ( ! moon f ! e>? has be5 det]m9$ f h] horizontal p>allax4 ,! angle ,e m ,h c be measur$4 ,e ,h m is a "r angle1 & ,e ,h1 ! radius ( ! e>?1 is kn[n 9 miles2 :5ce ! di/ance ( ! moon ,e m is easily f\nd4 ,annual p>allax is ! angle "u :i* ! diamet] ( ! e>?'s orbit w\ld be se5 if view$ f a />4 ,,note #aca1 p4 #eb4 ,! radii n ,b1 n ,g1 c41 fig4 #c1 are equal 9 any "o p>allel ( latitude1 ,a a ,b ,g2 !re=e a *ange 9 ! p>allax obs]v$ 9 t p>allel c only arise f a *ange 9 ! moon's di/ance f ! e>?2 & :5 ! moon is at h] mean di/ance1 :i* is a con/ant quantity equal to half ! major axis ( h] orbit1 a *ange 9 ! p>allax obs]v$ 9 diff]5t latitudes1 ,g & ,e1 mu/ arise f ! diff]5ce 9 ! l5g?s ( ! radii n ,g & ,c ,e4 ,,note #acb1 p4 #eb4 ,:5 ,v5us is 9 h] nodes4 ,%e mu/ be 9 ! l9e ,n ,s n :]e h] orbit ,p ,n ,a n cuts ! plane ( ! ecliptic ,e ,n e n1 fig4 #ab4 ,,note #acc1 p4 #ec4 ,! l9e describ$1 c4 ,let ,e1 fig4 #cc1 be ! e>?1 ,s ! c5tre ( ! sun1 & ,v ! planet ,v5us4 ,! real transit ( ! planet1 se5 f ,e ! c5tre ( ! e>?1 w\ld be 9 ! direction ,a ,b4 ,a p]son at ,w w\ld see x pass ov] ! sun 9 ! l9e v a1 & a p]son at ,o w\ld see x move across him 9 ! direction v a4 ,illu/ration3 ,fig4 #cc4 ,,note #acd1 p4 #ed4 ,kepl]'s law4 ,suppose x 7 requir$ to f9d ! di/ance ( ,jupit] f ! sun4 ,! p]iodic times ( ,jupit] & ,v5us are giv5 by obs]vation1 & ! mean di/ance ( ,v5us f ! c5tre ( ! sun is kn[n 9 miles or t]re/rial radii2 !re=e1 by ! rule ( ?ree1 ! squ>e root ( ! p]iodic "t ( ,v5us is to ! squ>e root ( ! p]iodic "t ( ,jupit] z ! cube root ( ! mean di/ance ( ,v5us f ! sun to ! cube root ( ! mean di/ance ( ,jupit] f ! sun1 :i* is ?us obta9$ 9 miles or t]re/rial radii4 ,! root ( a numb] is t numb] :i*1 once multipli$ by itself1 gives its squ>e2 twice multipli$ by itself1 gives its cube1 c4 ,= example1 twice #b are #d1 & twice #d are #h2 #b is !re=e ! squ>e root ( #d1 & ! cube root ( #h4 ,9 ! same mann] #c times #c are #i1 & #c times #i are #bg2 #c is !re=e ! squ>e root ( #i1 & ! cube root ( #bg4 ,,note #ace1 p4 #ee4 ,inv]sely1 c4 ,! quantities ( matt] 9 any two prim>y planets are great] 9 proportion z ! cubes ( ! numb]s repres5t+ ! mean di/ances ( _! satellites are great]1 & also 9 proportion z ! squ>es ( _! p]iodic times are less4 ,,note #acf1 p4 #ee4 ,z h>dly any?+ appe>s m impossible ?an t man %\ld h be5 able to weigh ! sun z x 7 9 scales & ! e>? 9 a balance1 ! me?od ( do+ s may h "s int]e/4 ,! attraction ( ! sun is to ! attraction ( ! e>? z ! quantity ( matt] 9 ! sun to ! quantity ( matt] 9 ! e>?2 &1 z ! =ce ( ?is reciprocal attraction is measur$ by its effects1 ! space ! e>? w\ld fall ?r\gh 9 a second by ! sun's attraction is to ! space :i* ! sun w\ld fall ?r\gh by ! e>?'s attraction z ! mass ( ! sun to ! mass ( ! e>?4 ,h5ce1 z _m times z ! fall ( ! e>? to ! sun 9 a second exce$s ! fall ( ! sun to ! e>? 9 ! same "t1 s _m times does ! mass ( ! sun exce$ ! mass ( ! e>?4 ,?us ! weight ( ! sun w be kn[n if ! l5g? ( ^! two spaces c be f\nd 9 miles or p>ts ( a mile4 ,no?+ c be easi]4 ,a heavy body falls ?r\gh #afjfig feet 9 a second at ! surface ( ! e>? by ! e>?'s attraction2 &1 z ! =ce ( gravity is inv]sely z ! squ>e ( ! di/ance1 x is cle> t #afjfig feet are to ! space a body w\ld fall ?r\gh at ! di/ance ( ! sun by ! e>?'s attraction1 z ! squ>e ( ! di/ance ( ! sun f ! e>? to ! squ>e ( ! di/ance ( ! c5tre ( ! e>? f its surface2 t is1 z ! squ>e ( #ie1jjj1jjj miles to ! squ>e ( #djjj miles4 ,& ?us1 by a simple "q 9 ! rule ( ?ree1 ! space :i* ! sun w\ld fall ?r\gh 9 a second by ! attraction ( ! e>? may be f\nd 9 p>ts ( a mile4 ,! space ! e>? w\ld fall ?r\gh 9 a second1 by ! attraction ( ! sun1 mu/ n[ be f\nd 9 miles also4 ,suppose m n1 fig4 #d1 to be ! arc :i* ! e>? describes r\nd ! sun 9 ,c1 9 a second ( "t1 by ! jo9t action ( ! sun & ! c5trifugal =ce4 ,by ! c5trifugal =ce alone ! e>? w\ld move f m to ,t 9 a second1 & by ! sun's attraction alone x w\ld fall ?r\gh ,t n 9 ! same "t4 ,h5ce ! l5g? ( ,t n1 9 miles1 is ! space ! e>? w\ld fall ?r\gh 9 a second by ! sun's attraction4 ,n[1 z ! e>?'s orbit is v ne>ly a circle1 if #cfj degrees be divid$ by ! numb] ( seconds 9 a sid]eal ye> ( #cfe-a_/d days1 x w give m n1 ! arc :i* ! e>? moves ?r\gh 9 a second1 & !n ! tables w give ! l5g? ( ! l9e ,c ,t 9 numb]s correspond+ to t angle2 b1 z ! radius ,c n is assum$ to be unity 9 ! tables1 if #a be subtract$ f ! numb] repres5t+ ,c ,t1 ! l5g? ( ,t n w be obta9$2 &1 :5 multipli$ by #ie1jjj1jjj1 to r$uce x to miles1 ! space :i* ! e>? falls ?r\gh1 by ! sun's attraction1 w be obta9$ 9 miles4 ,by ?is simple process x is f\nd t1 if ! sun 7 plac$ 9 "o scale ( a balance1 x w\ld require #ced1icf e>?s to =m a c\nt]poise4 ,,note #acg1 p4 #ei4 ,! sum ( ! greate/ & lea/ di/ances ,s ,p1 ,s ,a1 fig4 #ab1 is equal to ,p ,a1 ! major axis2 & _! diff]5ce is equal to twice ! exc5tricity ,c ,s4 ,! longitude ,s ,p ( ! planet1 :5 9 ! po9t ,p1 at its lea/ di/ance f ! sun1 is ! longitude ( ! p]ihelion4 ,! greate/ height ( ! planet above ! plane ( ! ecliptic ,e ,n e n1 is equal to ! incl9ation ( ! orbit ,p ,n ,a n to t plane4 ,! longitude ( ! planet1 :5 9 ! plane ( ! ecliptic1 c only be ! longitude ( "o ( ! po9ts ,n or n2 &1 :5 "o ( ^! po9ts is kn[n1 ! o!r is giv51 be+ #ahj di/ant f x4 ,la/ly1 ! "t includ$ betwe5 two consecutive passages ( ! planet ?r\gh ! same node ,n or n1 is its p]iodic "t1 all[ance be+ made = ! recess ( ! node 9 ! int]val4 ,,note #ach1 p4 #fj4 ,suppose t x 7 requir$ to f9d ! position ( a po9t 9 space1 z ( a planet1 & t "o obs]vation places x 9 n1 fig4 #cd1 ano!r obs]vation places x 9 n1 ano!r 9 n1 & s on2 all ! po9ts n1 n1 n1 n1 c41 be+ v ne> to "o ano!r4 ,! true place ( ! planet ,p w n diff] mu* f any ( ^! positions4 ,x is evid5t1 f ?is view ( ! subject1 t ,p n1 ,p n1 ,p n1 c41 are ! errors ( obs]vation4 ,! true position ( ! planet ,p is f\nd by ?is prop]ty1 t ! squ>es ( ! numb]s repres5t+ ! l9es ,p n1 ,p n1 c41 :5 add$ toge!r1 is ! lea/ possible4 ,ea* l9e ,p n1 ,p n1 c41 be+ ! :ole error 9 ! place ( ! planet1 is made up ( ! errors ( all ! elem5ts2 &1 :5 comp>$ ) ! errors obta9$ f !ory1 x af=ds ! means ( f9d+ ea*4 ,! pr9ciple ( lea/ squ>es is ( v g5]al application2 its demon/ration _c f9d a place "h2 b ! read] is ref]r$ to ,biot's ,a/ronomy1 vol4 ii4 p4 #bjc4 ,illu/ration3 ,fig4 #cd4 ,,note #aci1 p4 #fa4 ,! true longitude ( ,uranus 0 9 advance ( ! tables previ\s to #agie1 & cont9u$ to advance till #ahbb1 aft] :i* x dim9i%$ rapidly till #ahcj-a1 :5 ! obs]v$ & calculat$ longitudes agre$1 b !n ! planet fell beh9d ! calculat$ place s rapidly t x 0 cle> ! tables c\ld no long] repres5t its motion4 ,,note #adj1 p4 #fe4 ,an axis t1 c4 ,fig4 #bj repres5ts ! e>? revolv+ 9 its orbit ab\t ! sun 9 ,s1 ! axis ( rotation ,p p be+ ev]y:]e p>allel to itself4 ,,note #ada1 p4 #fe4 ,angul> velocities t are s5sibly uni=m4 ,! e>? & planets revolve ab\t _! axis ) an equable motion1 :i* is nev] ei!r fa/] or sl[]4 ,= example1 ! l5g? ( ! day is nev] m nor less ?an tw5ty-f\r h\rs4 ,,note #adb1 p4 #fh4 ,if fig4 #a be ! moon1 h] pol> diamet] ,n ,s is ! %orte/2 & ( ^? 9 ! plane ( ! equator1 ,q ,e q1 t :i* po9ts to ! e>? is great] ?an all ! o!rs4 ,,note #adc1 p4 #gc4 ,inv]sely proportional1 c4 ,t is1 ! total am\nt ( sol> radiation becomes less z ! m9or axis ,c ,c1 fig4 #bj1 ( ! e>?'s orbit becomes great]4 ,,note #add1 p4 #ge4 ,fig4 #ce repres5ts ! position ( ! app>5t orbit ( ! sun z x is at pres5t1 ! e>? be+ 9 ,e4 ,! sun is ne>] to ! e>? 9 mov+ ?r\gh ,p ?an 9 mov+ ?r\gh ,a 1 b its motion ?r\gh ,p is m rapid ?an its motion ?r\gh ,a 2 &1 z ! swiftness ( ! motion & ! quantity ( heat receiv$ v>y 9 ! same proportion1 a comp5sation takes place4 ,illu/ration3 ,fig4 #ce4 ,,note #ade1 p4 #gf4 ,9 an ellipsoid ( revolution1 fig4 #a1 ! pol> diamet] ,n ,s1 & e diamet] 9 ! equator q ,e ,q e1 are p]man5t axes ( rotation1 b ! rotation w\ld be un/able ab\t any o!r4 ,7 ! e>? to beg9 to rotate ab\t ,c a1 ! angul> di/ance f a to ! equator at q w\ld no long] be n9ety degrees1 :i* w\ld be imm$iately detect$ by ! *ange x w\ld occasion 9 ! latitudes4 ,,note #adf1 pp4 #ej1 #hj4 ,let q ,q1 & ,e e1 fig4 #aa1 be ! planes ( ! equator & ecliptic4 ,! angle e ,q1 :i* sep>ates !m1 call$ ! obliquity ( ! ecliptic1 v>ies 9 consequ5ce ( ! action ( ! sun & moon ^u ! protub]ant matt] at ! e>?'s equator4 ,t action br+s ! po9t ,q t[>ds e1 & t5ds to make ! plane q ,q co9cide ) ! ecliptic ,e e1 :i* causes ! equ9octial po9ts & to move sl[ly backw>ds on ! plane e ,e1 at ! rate ( #ejda annually4 ,?is "p ( ! motion1 :i* dep5ds ^u ! =m ( ! e>?1 is call$ luni-sol> precession4 ,ano!r "p1 totally indep5d5t ( ! =m ( ! e>?1 arises f ! mutual action ( ! e>?1 planets1 & sun1 :i*1 alt]+ ! position ( ! plane ( ! ecliptic e ,e1 causes ! equ9octial po9ts & to advance at ! rate ( ,o#ca annually2 b1 z ?is motion is mu* less ?an ! =m]1 ! equ9octial po9ts rec$e on ! plane ( ! ecliptic at ! rate ( #eja annually4 ,?is motion is call$ ! precession ( ! equ9oxes4 ,,note #adg1 p4 #ha4 ,let q ,q1 e ,e1 fig4 #cf1 be ! planes ( ! equ9octial or cele/ial equator & ecliptic1 & p1 ,p1 _! poles4 ,!n suppose p1 ! pole ( ! equator1 to revolve ) a tremul\s or wavy motion 9 ! little ellipse p c d b 9 ab\t #ai ye>s1 bo? motions be+ v small1 :ile ! po9t a is c>ri$ r\nd 9 ! circle a ,a ,b 9 #be1hfh ye>s4 ,! tremul\s motion may repres5t ! half-ye>ly v>iation1 ! motion 9 ! ellipse gives an idea ( ! nutation discov]$ by ,bradley1 & ! motion 9 ! circle a ,a ,b arises f ! precession ( ! equ9oxes4 ,! great] axis p d ( ! small ellipse is #ahe1 its m9or axis b c is #acgd4 ,^! motions are s small t !y h v little effect on ! p>allelism ( ! axis ( ! e>?'s rotation dur+ its revolution r\nd ! sun1 z repres5t$ 9 fig4 #bj4 ,z ! />s are fix$1 ?is real motion 9 ! pole ( ! e>? mu/ cause an app>5t *ange 9 _! places4 ,illu/ration3 ,fig4 #cf4 ,illu/ration3 figure3 equidi/ant wires 9 an eye-piece ,,note #adh1 p4 #hc4 ,by means ( a transit in/rum5t1 :i* is a telescope m\nt$ s z to revolve only 9 ! plane ( ! m]idian1 ! in/ant ( ! transit or passage ( a cele/ial body across ! m]idian c be det]m9$4 ,! transits ( ! pr9cipal />s are us$ to asc]ta9 ! "t1 or1 :i* is ! same ?+1 ! am\nt ( ! error ( clocks4 ,a sy/em ( equidi/ant wires1 z repres5t$ 9 ! figure1 is plac$ 9 ! focus ( ! eye-piece1 s t ! middle wire is p]p5dicul> & at "r angles to ! axis ( ! telescope4 ,x consequ5tly repres5ts a portion ( ! cele/ial m]idian2 & :5 a /> is se5 to cross t wire x !n crosses ! cele/ial m]idian ( ! place ( obs]vation4 ,a clock beat+ seconds be+ close at h&1 ! duty ( an obs]v] is to note ! exact second & "p ( a second at :i* a /> crosses ea* wire successively 9 consequ5ce ( ! rotation ( ! e>?4 ,!n ! mean ( all ^! obs]vations w give ! "t at :i* ! /> crosses ! cele/ial m]idian ( ! place ( obs]vation to ! t5? ( a second1 provid$ ! obs]vations are accurate4 ,n[ x happ5s t ! simultane\s impression on ! eye & e> is e/imat$ diff]5tly by diff]5t obs]v]s1 s t "o p]son w note ! transit ( a />1 = example1 z happ5+ ! fraction ( a second soon] or lat] ?an ano!r p]son2 & z t is ! case 9 e obs]vation he makes1 x is call$ 8 p]sonal equation1 t is to say1 x is a correction t mu/ be appli$ to all ! obs]vations ( ! individual1 & a curi\s in/ance ( individuality x is4 ,= in/ance1 ,m4 ,otto ,/ruve notes e obs]vation ,o#aa too soon1 ,m4 ,pet]s ,o#ac too late2 ,m4 ,/ruve not$ e obs]vation "o second lat] ?an ,m4 ,bessel1 & ,m4 ,argel&] e/imat$ ! transit ( a /> #ab lat] ?an ,m4 ,bessel4 ,all ^! g5tlem5 7 or are fir/-rate obs]v]s2 & :5 ! p]sonal equation is kn[n x is easy to correct ! obs]vations4 ,h[ev]1 to avoid t inconv5i5ce ,mr4 ,bond has introduc$ a me?od 9 ! ,obs]vatory at ,cambridge 9 ! ,unit$ ,/ates 9 :i* t\* is comb9$ ) sight in/ead ( he>+1 :i* is n[ us$ also at ,gre5wi*4 ,! obs]v] at ! mom5t ( ! obs]vation presses 8 f+]s on a ma*9e :i* by means ( a galvanic batt]y conveys ! impression to :]e "t is measur$ & m>k$1 s t ! obs]vation is at once record$ & ! p]sonal equation avoid$4 ,,note #adi1 p4 #hd4 ,let ,n be ! pole1 fig4 #aa1 e ,e ! ecliptic1 & ,q q ! equator4 ,!n1 ,n n m ,s be+ a m]idian1 & at "r angles to ! equator1 ! arc m is less ?an ! arc n4 ,,note #aej1 p4 #he4 ,heliacal ris+ ( ,sirius4 ,:5 ! /> appe>s 9 ! morn+1 9 ! horizon1 a little be=e ! ris+ ( ! sun4 ,,note #aea1 p4 #hg4 ,let ,p ,a 1 fig4 #ce1 be ! app>5t orbit or pa? ( ! sun1 ! e>? be+ 9 ,e4 ,its major axis1 ,a ,p1 is at pres5t situate z 9 ! figure1 :]e ! sol> p]igee ,p is betwe5 ! sol/ice ( w9t] & ! equ9ox ( spr+4 ,s t ! "t ( ! sun's passage ?r\gh ! arc ,a is great] ?an ! "t he takes to g ?r\gh ! arc ,p 4 ,! major axis ,a ,p co9cid$ ) 1 ! l9e ( ! equ9oxes1 #djjj ye>s be=e ! ,*ri/ian era2 at t "t ,p 0 9 ! po9t 4 ,9 #fdfh ( ! ,*ri/ian era ! p]igee ,p w co9cide ) 4 ,9 #abcd ,a4,d4 ! major axis 0 p]p5dicul> to 1 & !n ,p 0 9 ! w9t] sol/ice4 ,,note #aeb1 p4 #hh4 ,at ! sol/ices1 c4 ,s9ce ! decl9ation ( a cele/ial object is its angul> di/ance f ! equ9octial1 ! decl9ation ( ! sun at ! sol/ice is equal to ! arc ,q e1 fig4 #aa1 :i* measures ! obliquity ( ! ecliptic1 or angul> di/ance ( ! plane e f ! plane ,q 4 ,,note #aec1 p4 #hh4 ,z5i? di/ance is ! angul> di/ance ( a cele/ial object f ! po9t imm$iately ov] ! head ( an obs]v]4 ,,note #aed1 p4 #hi4 ,r$uc$ to ! level ( ! sea4 ,! =ce ( gravitation decreases z ! squ>e ( ! height above ! surface ( ! e>? increases1 s t a p5dulum vibrates sl[] on high gr\nd2 &1 9 ord] to h a /&>d indep5d5t ( local circum/ances1 x is necess>y to r$uce x to ! l5g? t w\ld exactly make #hf1djj vibrations 9 a mean sol> day at ! level ( ! sea4 ,,note #aee1 p4 #ij4 ,a quadrant ( ! m]idian is a f\r? "p ( a m]idian1 or an arc ( a m]idian conta9+ #ij1 z ,n ,q1 fig4 #aa4 ,,note #aef1 p4 #ic4 ,moon's s\?+4 ,! "t :5 ! moon is on ! m]idian ( any place1 :i* happ5s ab\t =ty-eight m9utes lat] e day4 ,,note #aeg1 p4 #if4 ,! angul> velocity ( ! e>?'s rotation is at ! rate ( #ahj 9 twelve h\rs1 :i* is ! "t includ$ betwe5 ! passages ( ! moon at ! upp] & "u m]idian4 ,,note #aeh1 p4 #if4 ,if ,s be ! e>?1 fig4 #ad1 d ! sun1 & ,c ,q ,o ,d ! orbit ( ! moon1 !n ,c & ,o are ! syzygies4 ,:5 ! moon is new1 %e is at ,c1 & :5 full %e is at ,o2 &1 z bo? sun & moon are !n on ! same m]idian1 x occasions ! spr+-tides1 x be+ high wat] at places "u ,c & ,o1 :ile x is l[ wat] at ^? "u ,q & ,d4 ,! neap-tides happ5 :5 ! moon is 9 quadrature at ,q or ,d1 = !n %e is di/ant f ! sun by ! angle d ,s ,q1 or d ,s ,d1 ea* ( :i* is #ij4 ,,note #aei1 p4 #ig4 ,decl9ation4 ,if ! e>? be 9 ,c1 fig4 #aa1 & if q ,q be ! equ9octial1 & ,n m ,s a m]idian1 !n m ,c n is ! decl9ation ( a body at n4 ,!re=e ! cos9e ( t angle is ! cos9e ( ! decl9ation4 ,,note #afj1 pp4 #ii1 #aca4 ,fig #cg %[s ! propagation ( waves f two po9ts ,c & ,c1 :]e /ones are suppos$ to h fall54 ,^? po9ts 9 :i* ! waves cross ea* o!r are ! places :]e !y c\nt]act ea* o!r's effects1 s t ! wat] is smoo? !re1 :ile x is agitat$ 9 ! int]m$iate spaces4 ,,note #afa1 p4 #ajj4 ,! c5trifugal =ce may1 c4 ,! c5trifugal =ce acts 9 a direction at "r angles to ,n ,s1 ! axis ( rotation1 fig4 #cj4 ,its effects are equival5t to two =ces1 "o ( :i* is 9 ! direction b m p]p5dicul> to ! surface ,q m n ( ! e>?1 & dim9i%es ! =ce ( gravity at m4 ,! o!r acts 9 ! direction ( ! tang5t m ,t1 :i* makes ! fluid p>ticles t5d t[>ds ! equator4 ,illu/ration3 ,fig4 #cg4 ,,note #afb1 p4 #ajf4 ,analytical =mula or expression4 ,a comb9ation ( symbols or signs express+ or repres5t+ a s]ies ( calculation1 & includ+ e p>ticul> case t c arise f a g5]al law4 ,,note #afc1 p4 #ajf4 ,fig4 #ch is a p]fect octah$ron4 ,sometimes its angles1 ,a1 ,x1 a1 a1 c41 are truncat$1 or cut (f4 ,sometimes a slice is cut (f its edges ,a a1 ,x a1 a a1 c4 ,occasionally bo? ^! modifications take place4 ,illu/ration3 ,fig4 #ch4 ,,note #afd1 p4 #ajg4 ,prismatic cry/als ( sulphate ( nickel are some:at l fig4 #fb1 only t !y are ?91 l a hair4 ,,note #afe1 p4 #ajh4 ,z9c1 a metal ei!r f\nd z an ore or mix$ ) o!r metals4 ,x is us$ 9 mak+ brass4 ,,note #aff1 p4 #ajh4 ,a cube is a solid conta9$ by six plane squ>e surfaces1 z fig4 #ci4 ,illu/ration3 ,fig4 #ci4 ,,note #afg1 p4 #ajh4 ,a tetrah$ron is a solid conta9$ by f\r triangul> surfaces1 z fig4 #dj3 ( ?is solid !re are _m v>ieties4 ,illu/ration3 ,fig4 #dj4 ,,note #afh1 p4 #ajh4 ,!re are _m v>ieties ( ! octah$ron4 ,9 t m5tion$ 9 ! text1 ! base a a a a1 fig4 #ch1 is a squ>e1 b ! base may be a rhomb2 ?is solid may also be elongat$ 9 ! direction ( its axis ,a ,x1 or x may be depress$4 ,,note #afi1 pp4 #aji1 #aib1 #bgc4 ,a rhomboh$ron is a solid conta9$ by six plane surfaces1 z 9 fig4 #fc1 ! opposite planes be+ equal & simil> rhombs p>allel to "o ano!r2 b all ! planes are n necess>ily equal or simil>1 nor are its angles "r angles4 ,9 c>bonate ( lime ! angle ,c ,a ,b is #ajeee1 & ! angle ,b or ,c is #geje4 ,,note #agj1 p4 #aji4 ,sublimation4 ,bodies rais$ into vap\r :i* is aga9 cond5s$ into a solid /ate4 ,,note #aga1 p4 #aab4 ,plat9um4 ,! heavie/ ( metals2 its col\r is betwe5 t ( silv] & lead4 ,,note #agb1 p4 #aac4 ,! surface ( a column ( wat]1 or _s ( w9e1 9 a capill>y tube1 is holl[2 & t ( a column ( quicksilv] is convex1 or r\nd$1 z 9 fig4 #da4 ,,note #agc1 p4 #aac4 ,inv]se ratio1 c4 ,! elevation ( ! liquid is great] 9 proportion z ! int]nal diamet] ( ! tube is less4 ,,note #agd1 p4 #aad4 ,9 fig4 #da ! l9e c d %[s ! direction ( ! result+ =ce 9 ! two cases4 ,illu/ration3 ,fig4 #da4 ,,note #age1 p4 #aae4 ,:5 two plates ( glass are br\ght ne> to "o ano!r 9 wat]1 ! liquid rises betwe5 !m2 &1 if ! plates t\* ea* o!r at "o ( _! upright edges1 ! outl9e ( ! wat] w become an hyp]bola4 ,,note #agf1 p4 #aae4 ,let ,a ,a1 fig4 #db1 be two plates1 bo? ( :i* are wet1 & ,b ,b two t are dry4 ,:5 p>tly imm]s$ 9 a liquid1 its surface w be curv$ close to !m1 b w be ( its usual level = ! re/ ( ! di/ance4 ,at su* a di/ance !y w nei!r attract nor repel "o ano!r4 ,b1 z soon z !y are br\ght ne> en\gh to h ! :ole ( ! liquid surface betwe5 !m curv$1 z 9 a a1 b b1 !y w ru% toge!r4 ,if "o be wet & ano!r dry1 z ,c ,c1 !y w repel "o ano!r at a c]ta9 di/ance2 b1 z soon z !y are br\ght v ne>1 !y w ru% toge!r1 z 9 ! =m] cases4 ,illu/ration3 ,fig4 #db4 ,,note #agg1 p4 #abc4 ,9 a pap] on ! atmosph]ic *anges t produce ra9 & w9d1 by ,?omas ,hopk9s1 ,esq41 9 ! ,geographical ,j\rnal1 x is %[n t1 :5 vap\r is cond5s$ & falls 9 ra91 a p>tial vacuum is =m$1 & t heavi] air presses 9 z a curr5t ( w9d4 ,?us ! vacuum aris+ f ! great precipitation at ! tropics causes ! pol> w9ds to desc5d f ! upp] regions ( ! atmosph]e & bl[ along ! surface to ! equator z trade w9ds to supply ! place ( ! hot curr5ts t are cont9ually rais+ !m into ! high] regions4 ,?is circum/ance removes ! only difficulty 9 ,lieut5ant ,maury's !ory ( ! w9ds4 ,,note #agh1 p4 #acd4 ,lat5t or absorb$ heat4 ,!re is a c]ta9 quantity ( heat 9 all bodies1 :i* _c be detect$ by ! !rmomet]1 b :i* may become s5sible by compression4 ,,note #agi1 p4 #acg4 ,reflect$ waves4 ,a s]ies ( waves ( light1 s\nd1 or wat]1 div]ge 9 all directions f _! orig9 ,i1 fig4 #dc1 z f a c5tre4 ,:5 !y meet ) an ob/acle ,s ,s1 !y /rike aga9/ x1 & are reflect$ or turn$ back by x 9 ! same =m z if !y _h proce$$ f ! c5tre ,c1 at an equal di/ance on ! o!r side ( ! surface ,s ,s4 ,illu/ration3 ,fig4 #dc4 ,,note #ahj1 p4 #ach4 ,elliptical %ell4 ,if fig4 #f be a section ( an elliptical %ell1 !n all s\nds com+ f ! focus ,s to diff]5t po9ts on ! surface1 z m1 are reflect$ back to ,f1 because ! angle ,t m ,s is equal to t m ,f4 ,9 a sph]ical holl[ %ell1 a s\nd div]g+ f ! c5tre is reflect$ back to ! c5tre aga94 ,,note #aha1 p4 #adb4 ,fig4 #dd repres5ts musical /r+s 9 vibration2 ! /raight l9es are ! /r+s :5 at re/4 ,! fir/ figure ( ! f\r w\ld give ! fundam5tal note1 z1 = example1 ! l[ ,c4 ,! second & ?ird figures w\ld give ! fir/ & second h>monics2 t is1 ! octave & ! #ab? above ,c1 n n n be+ ! po9ts at re/2 ! f\r? figure %[s ! real motion :5 comp\nd$ ( all ?ree4 ,illu/ration3 ,fig4 #dd4 ,,note #ahb1 p4 #adc4 ,fig4 #de repres5ts sections ( an op5 & ( a %ut pipe1 & ( a pipe op5 at "o end4 ,:5 s\nd$1 ! air spontane\sly divides itself into segm5ts4 ,x rema9s at re/ 9 ! divisions or nodes n n1 c41 b vibrates betwe5 !m 9 ! direction ( ! arr[-heads4 ,! undulations ( ! :ole column ( air give ! fundam5tal note1 :ile ! vibrations ( ! divisions give ! h>monics4 ,illu/ration3 ,fig4 #de4 ,,note #ahc1 p4 #add4 ,fig4 #a1 plate #a1 %[s ! vibrat+ surface :5 ! s& divides x into squ>es1 & fig4 #b repres5ts ! same :5 ! nodal l9es divide x into triangles4 ,! portions m>k$ a a are 9 diff]5t /ates ( vibration f ^? m>k$ b b4 ,,note #ahd1 p4 #ade4 ,plates #a & #b conta9 a few ( ,*ladni's figures4 ,! :ite l9es are ! =ms assum$ by ! s&1 f diff]5t modes ( vibration1 correspond+ to musical notes ( diff]5t degrees ( pit*4 ,plate #c conta9s six ( ,*ladni's circul> figures4 ,,note #ahe1 p4 #ade4 ,mr4 ,:eat/one's pr9ciple is1 t :5 vibrations produc+ ! =ms ( figs4 #a & #b1 plate #c1 are unit$ 9 ! same surface1 !y make ! s& assume ! =m ( fig4 #c4 ,9 ! same mann]1 ! vibrations :i* w\ld sep>ately cause ! s& to take ! =ms ( figs4 #d & #e1 w\ld make x assume ! =m 9 fig4 #f :5 unit$4 ,! figure #i results f ! modes ( vibration ( #g & #h comb9$4 ,! p>ts m>k$ a a are 9 diff]5t /ates ( vibration f ^? m>k$ b b4 ,figs4 #a1 #b1 & #c1 plate #d1 repres5t =ms :i* ! s& takes 9 consequ5ce ( simple modes ( vibration2 #d & #e are ^? aris+ f two comb9$ modes ( vibration2 & ! la/ six figures arise f f\r sup]impos$ simple modes ( vibration4 ,^! complicat$ figures are det]m9$ by computation indep5d5t ( exp]im5t4 ,,note #ahf1 p4 #adf4 ,! long cross-l9es ( fig4 #df %[ ! two sy/ems ( nodal l9es giv5 by ,m4 ,sav>t's lam94 ,illu/ration3 ,fig4 #df4 ,,note #ahg1 p4 #adf4 ,! %ort l9es on fig4 #df %[ ! positions ( ! nodal l9es on ! o!r sides ( ! same lam94 ,,note #ahh1 p4 #adf4 ,fig4 #dg gives ! nodal l9es on a cyl9d]1 ) ! pap] r+s t m>k ! quiesc5t po9ts4 ,illu/ration3 ,fig4 #dg4 ,illu/ration3 ,fig4 #dh4 ,,note #ahi1 pp4 #ach1 #aec1 #aef4 ,reflection & ,refraction4 ,let ,p ,c p1 fig4 #dh1 be p]p5dicul> to a surface ( glass or wat] ,a ,b4 ,:5 a ray ( light1 pass+ ?r\gh ! air1 falls on ?is surface 9 any direction ,i ,c1 "p ( x is reflect$ 9 ! direction ,c ,s1 & ! o!r "p is b5t at ,c1 & passes ?r\gh ! glass or wat] 9 ! direction ,c ,r4 ,i ,c is call$ ! incid5t ray1 & ,i ,c ,p ! angle ( incid5ce2 ,c ,s is ! reflect$ ray1 & ,p ,c ,s ! angle ( reflection2 ,c ,r is ! refract$ ray1 & p ,c ,r ! angle ( refraction4 ,! plane pass+ ?r\gh ,s ,c & ,i ,c is ! plane ( reflection1 & ! plane pass+ ?r\gh ,i ,c & ,c ,r is ! plane ( refraction4 ,9 ord9>y cases1 ,c ,i1 ,c ,s1 ,c ,r1 are all 9 ! same plane4 ,we see ! surface by means ( ! reflect$ light1 :i* w\ld o!rwise be invisible4 ,:atev] ! reflect+ surface may be1 & h[ev] obliquely ! light may fall ^u x1 ! angle ( reflection is always equal to ! angle ( incid5ce4 ,?us ,i ,c1 ,i ,c1 be+ rays incid5t on ! surface at ,c1 !y w be reflect$ into ,c ,s1 ,c ,s1 s t ! angle ,s ,c ,p w be equal to ! angle ,i ,c ,p1 & ,s ,c ,p equal to ,i ,c ,p4 ,t is by no means ! case ) ! refract$ rays4 ,! incid5t rays ,i ,c1 ,i ,c1 are b5t at ,c t[>ds ! p]p5dicul>1 9 ! direction ,c ,r1 ,c ,r2 & ! law ( refraction is su*1 t ! s9e ( ! angle ( incid5ce has a con/ant ratio to ! s9e ( ! angle ( refraction2 t is to say1 ! numb] express+ ! l5g? ( ,i m1 ! s9e ( ,i ,c ,p1 divid$ by ! numb] express+ ! l5g? ( ,r n1 ! s9e ( ,r ,c p1 is ! same = all ! rays ( light t c fall ^u ! surface ( any "o sub/ance1 & is call$ its index ( refraction4 ,?\gh ! index ( refraction be ! same = any "o sub/ance1 x is n ! same = all sub/ances4 ,= wat] x is #accf2 = cr[n-glass x is #aece2 = fl9t-glass1 #af2 = diamond1 #bdhg2 & = *romate ( lead x is #c1 :i* sub/ance has a high] refractive p[] ?an any o!r kn[n4 ,light fall+ p]p5dicul>ly on a surface passes ?r\gh x )\t be+ refract$4 ,if ! light be n[ suppos$ to pass f a d5se into a r>e m$ium1 z f glass or wat] into air1 !n ,r ,c1 ,r ,c1 become ! incid5t rays2 & 9 ?is case ! refract$ rays1 ,c ,i1 ,c ,i1 are b5t f ! p]p5dicul> in/ead ( t[>ds x4 ,:5 ! incid5ce is v oblique1 z r ,c1 ! light nev] passes into ! air at all1 b x is totally reflect$ 9 ! direction ,c r1 s t ! angle p ,c r is equal to p ,c r2 t frequ5tly happ5s at ! second surface ( glass4 ,:5 a ray ,i ,c falls f air ^u a piece ( glass ,a ,b1 x is 9 g5]al refract$ at ea* surface4 ,at ,c x is b5t t[>ds ! p]p5dicul>1 & at ,r f x1 & ! ray em]ges p>allel to ,i ,c2 b1 :5 ! ray is v oblique to ! second surface1 x is totally reflect$4 ,an object se5 by total reflection is ne>ly z vivid z :5 se5 by direct vision1 because no "p ( ! light is refract$4 ,:5 light falls ^u a plate ( cr[n-glass1 at an angle ( #d #cb c\nt$ f ! surface1 ! glass reflects #d times m light ?an x transmits4 ,at an angle ( #g #a ! reflect$ light is d\ble ( ! transmitt$2 at an angle ( #aa #h ! light reflect$ is equal to t transmitt$2 at #ag #ag ! reflect$ is equal to #a_/b ! transmitt$ light2 at #bf #ch x is equal to #a_/d1 ! v>iation1 accord+ to ,arago1 be+ z ! squ>e ( ! cos9e4 ,,note #ahi1 p4 #aed4 ,atmosph]ic refraction4 ,let a b1 a b1 c41 fig4 #di1 be /rata1 or extremely ?9 lay]s1 ( ! atmosph]e1 :i* increase 9 d5sity t[>ds m n1 ! surface ( ! e>?4 ,a ray com+ f a /> meet+ ! surface ( ! atmosph]e at ,s w\ld be refract$ at ! surface ( ea* lay]1 & w\ld consequ5tly move 9 ! curv$ l9e ,s v v v ,a2 & z an object is se5 9 ! direction ( ! ray t meets ! eye1 ! />1 :i* really is 9 ! direction ,a ,s1 w\ld seem to a p]son at ,a to be 9 s4 ,s t refraction1 :i* always acts 9 a v]tical direction1 raises objects above _! true place4 ,= t reason1 a body at ,s1 bel[ ! horizon ,h ,a ,o1 w\ld be rais$1 & w\ld be se5 9 s4 ,! sun is frequ5tly visible by refraction aft] he is set1 or be=e he is ris54 ,!re is no refraction 9 ! z5i? at ,z4 ,x increases all ! way to ! horizon1 :]e x is greate/1 ! v>iation be+ proportional to ! tang5t ( ! angles ,z ,a ,s1 ,z ,a ,s1 ! di/ances ( ! bodies ,s ,s f ! z5i?4 ,! m obliquely ! rays fall1 ! great] ! refraction4 ,illu/ration3 ,fig4 #di4 ,illu/ration3 ,fig4 #ej4 ,,note #aij1 p4 #aed4 ,bradley's me?od ( asc]ta9+ ! am\nt ( refraction4 ,let ,z1 fig4 #ej1 be ! z5i? or po9t imm$iately above an obs]v] at ,a2 let ,h ,o be 8 horizon1 & ,p ! pole ( ! equ9octial ,a ,q4 ,h5ce ,p ,a ,q is a "r angle4 ,a /> z ne> to ! pole z s w\ld appe> to revolve ab\t x1 9 consequ5ce ( ! rotation ( ! e>?4 ,at noon1 = example1 x w\ld be at s above ! pole1 & at midnight x w\ld be 9 s bel[ x4 ,! sum ( ! true z5i? di/ances1 ,z ,a s1 ,z ,a s1 is equal to twice ! angle ,z ,a ,p4 ,aga91 ,s & ,s be+ ! sun at 8 greate/ di/ances f ! equ9octial ,a ,q :5 9 ! sol/ices1 ! sum ( 8 true z5i? di/ances1 ,z ,a ,s1 ,z ,a ,s1 is equal to twice ! angle ,z ,a ,q4 ,consequ5tly1 ! f\r true z5i? di/ances1 :5 add$ toge!r1 are equal to twice ! "r angle ,q ,a ,p2 t is1 !y are equal to #ahj4 ,b ! obs]v$ or app>5t z5i? di/ances are less ?an ! true on acc\nt ( refraction2 !re=e ! sum ( ! f\r app>5t z5i? di/ances is less ?an #ahj by ! :ole am\nt ( ! f\r refractions4 ,,note #aia1 p4 #aee4 ,t]re/rial refraction4 ,let ,c1 fig4 #ea1 be ! c5tre ( ! e>?1 ,a an obs]v] at its surface1 ,a ,h 8 horizon1 & ,b "s di/ant po9t1 z ! top ( a hill4 ,let ! arc ,b ,a be ! pa? ( a ray com+ f ,b to ,a2 ,e ,b1 ,e ,a1 tang5ts to its extremities2 & ,a ,g1 ,b ,f1 p]p5dicul> to ,c ,b4 ,h[ev] high ! hill ,b may be1 x is no?+ :5 comp>$ ) ,c ,a1 ! radius ( ! e>?2 consequ5tly1 ,a ,b diff]s s little f ,a ,d t ! angles ,a ,e ,b & ,a ,c ,b are supplem5t>y to "o ano!r2 t is1 ! two tak5 toge!r are equal to #ahj4 ,a ,c ,b is call$ ! horizontal angle4 ,n[ ,b ,a ,h is ! real height ( ,b1 & ,e ,a ,h its app>5t height2 h5ce refraction raises ! object ,b1 by ! angle ,e ,a ,b1 above its real place4 ,aga91 ! real depression ( ,a1 :5 view$ f ,b1 is ,f ,b ,a1 :]eas its app>5t depression is ,f ,b ,e1 s ,e ,b ,a is due to refraction4 ,! angle ,f ,b ,a is equal to ! sum ( ! angles ,b ,a ,h & ,a ,c ,b2 t is1 ! true elevation is equal to ! true depression & ! horizontal angle4 ,b ! true elevation is equal to ! app>5t elevation dim9i%$ by ! refraction2 & ! true depression is equal to ! app>5t depression increas$ by refraction4 ,h5ce twice ! refraction is equal to ! horizontal angle augm5t$ by ! diff]5ce betwe5 ! app>5t elevation & ! app>5t depression4 ,illu/ration3 ,fig4 #ea4 ,,note #aib1 p4 #aee4 ,fig4 #eb repres5ts ! ph5om5on 9 "q4 ,s ,p is ! real %ip1 ) its inv]t$ & direct images se5 9 ! air4 ,7 !re no refraction1 ! rays w\ld come f ! %ip ,s ,p to ! eye ,e 9 ! direction ( ! /raight l9es2 b1 on acc\nt ( ! v>iable d5sity ( ! inf]ior /rata ( ! atmosph]e1 ! rays are b5t 9 ! curv$ l9es ,p c ,e1 ,p d ,e1 ,s m ,e1 ,s n ,e4 ,s9ce an object is se5 9 ! direction ( ! tang5t to t po9t ( ! ray :i* meets ! eye1 ! po9t ,p ( ! real %ip is se5 at p & p1 & ! po9t ,s seems to be 9 s & s2 &1 z all ! o!r po9ts are transf]r$ 9 ! same mann]1 direct & inv]t$ images ( ! %ip are =m$ 9 ! air above x4 ,illu/ration3 ,fig4 #eb4 ,,note #aic1 p4 #aef4 ,fig4 #ec repres5ts ! section ( a pok]1 ) ! refraction produc$ by ! hot air surr\nd+ x4 ,illu/ration3 ,fig4 #ec4 ,,note #aid1 p4 #aef4 ,! sol> spectrum4 ,a ray f ! sun at ,s1 fig4 #ed1 admitt$ into a d>k room1 ?r\gh a small r\nd hole ,h 9 a w9d[-%utt]1 proce$s 9 a /raight l9e to a scre5 ,d1 on :i* x =ms a bright circul> spot ( :ite light1 ( ne>ly ! same diamet] ) ! hole ,h4 ,b :5 ! refract+ angle ,b ,a ,c ( a glass prism is int]pos$1 s t ! sunbeam falls on ,a ,c ! fir/ surface ( ! prism1 & em]ges f ! second surface ,a ,b at equal angles1 x causes ! rays to deviate f ! /raight pa? ,s ,d1 & b5ds !m to ! scre5 ,m ,n1 :]e !y =m a col\r$ image ,v ,r ( ! sun1 ( ! same bread? ) ! diamet] ( ! hole ,h1 b mu* long]4 ,! space ,v ,r consi/s ( sev5 col\rs--violet1 indigo1 blue1 gre51 yell[1 orange1 & r$4 ,! violet & r$1 be+ ! mo/ & lea/ refrangible rays1 are at ! extremities1 & ! gre5 occupy ! middle "p at ,g4 ,! angle ,d g ,g is call$ ! mean deviation1 & ! spread+ ( ! col\r$ rays ov] ! angle ,v g ,r ! disp]sion4 ,! deviation & disp]sion v>y ) ! refract+ angle ,b ,a ,c ( ! prism1 & ) ! sub/ance ( :i* x is made4 ,illu/ration3 ,fig4 #ed4 ,,note #aie1 pp4 #aei1 #afd4 ,"u ! same circum/ances1 & :]e ! refract+ angles ( ! two prisms are equal1 ! angles ,d g ,g & ,v g ,r1 fig4 #ed1 are great] = fl9t-glass ?an = cr[n-glass4 ,b1 z !y v>y ) ! angle ( ! prism1 x is only necess>y to augm5t ! refract+ angle ( ! cr[n-glass prism by a c]ta9 quantity1 to produce ne>ly ! same deviation & disp]sion ) ! fl9t-glass prism4 ,h5ce1 :5 ! two prisms are plac$ ) _! refract+ angles 9 opposite directions1 z 9 fig4 #ed1 !y ne>ly neutralize ea* o!r's effects1 & refract a beam ( light )\t resolv+ x into its elem5t>y col\r$ rays4 ,sir ,david ,brew/] has come to ! conclusion t !re may be refraction )\t col\r by means ( two prisms1 or two l5ses1 :5 prop]ly adju/$1 ev5 ?\gh !y be made ( ! same k9d ( glass4 ,,note #aif1 p4 #afe4 ,! object glass ( ! a*romatic telescope consi/s ( a convex l5s ,a ,b1 fig4 #ee1 ( cr[n-glass plac$ on ! outside1 t[>ds ! object1 & ( a concave-convex l5s ,c ,d ( fl9t-glass1 plac$ t[>ds ! eye4 ,! focal l5g? ( a l5s is ! di/ance ( its c5tre f ! po9t 9 :i* ! rays conv]ge1 z ,f1 fig4 #fj4 ,if1 !n1 ! l5ses ,a ,b & ,c ,d be s con/ruct$ t _! focal l5g?s are 9 ! same proportion z _! disp]sive p[]s1 !y w refract rays ( light )\t col\r4 ,illu/ration3 ,fig4 #ee4 ,,note #aig1 p4 #afe4 ,if ! mean refract+ angle ( ! prism ,d g ,g1 fig4 #ed1 7 ! same = all sub/ances1 !n ! diff]5ce ,d g ,v - ,d g ,r w\ld be ! disp]sion4 ,b ! angle ( ! prism be+ ! same1 all ^! angles are diff]5t 9 ea* sub/ance1 s t 9 ord] to obta9 ! disp]sion ( any sub/ance ! angle ,d g ,v - ,d g ,r mu/ be divid$ by ! angle ,d g ,g or its excess above unity1 to :i* ! mean refraction is always proportional4 ,accord+ to ,mr4 ,fraunh(] ! refraction ( ! extreme violet & r$ rays 9 cr[n-glass is #aedff & #aebeh2 s ,d g ,v - ,d g ,r #aedff - #aebeh #jbjh1 & half ! sum ( ! excess ( ea* above unity is #ecfb2 consequ5tly 7,d g ,v - ,d g ,r7_/,d g ,g #jbjh_/ecfb #jjchgi2 = diamond 7,d g ,v - ,d g ,r7_/,d g ,g 7#bdfg - #bdaa7_/adci #jjchi2 s t ! disp]sive p[] ( diamond is a little less ?an t ( cr[n-glass2 h5ce ! spl5did refract$ col\rs :i* di/+ui% diamond f e o!r preci\s /one are n ow+ to its high disp]sive p[]1 b to its great mean refraction4--,,sir ,,david ,,brew/]4 ,,note #aih1 p4 #afh4 ,:5 a sunbeam1 aft] hav+ pass$ ?r\gh a col\r$ glass ,v ,v1 fig4 #ef1 ent]s a d>k room by two small slits ,o ,o 9 a c>d1 or piece ( t91 !y produce alt]nate bright & black b&s on a scre5 ,s ,s at a little di/ance4 ,:5 ei!r "o or o!r ( ! slits ,o or ,o is /opp$1 ! d>k b&s vani%1 & ! scre5 is illum9at$ by a uni=m light1 prov+ t ! d>k b&s are produc$ by ! int]f]5ce ( ! two sets ( rays4 ,aga91 let ,h m1 fig4 #eg1 be a beam ( :ite light pass+ ?r\gh a hole at ,h1 made ) a f9e ne$le 9 a piece ( lead or a c>d1 & receiv$ on a scre5 ,s ,s4 ,:5 a hair1 or a small slip ( c>d h h1 ab\t ! #cj? ( an in* 9 bread?1 is held 9 ! beam1 ! rays b5d r\nd on ea* side ( x1 &1 arriv+ at ! scre5 9 diff]5t /ates ( vibration1 int]f]e & =m a s]ies ( col\r$ fr+es on ea* side ( a c5tral :ite b& m4 ,:5 a piece ( c>d is int]pos$ at ,c1 s z to int]cept ! light :i* passes on "o side ( ! hair1 ! col\r$ fr+es vani%4 ,:5 homog5e\s light is us$1 ! fr+es are broade/ 9 r$1 & become n>r[] = ea* col\r ( ! spectrum progressively to ! violet1 :i* gives ! n>r[e/ & mo/ cr[d$ fr+es4 ,^! v elegant exp]im5ts are due to ,dr4 ,?omas ,"y4 ,illu/ration3 ,fig4 #ef4 ,illu/ration3 ,fig4 #eg4 ,illu/ration3 ,fig4 #eh4 ,,note #aii1 pp4 #aga1 #bjj4 ,fig4 #eh %[s ,newton's r+s1 ( :i* !re are sev51 =m$ by screw+ two l5ses ( glass toge!r4 ,provid$ ! incid5t light be :ite1 !y always succe$ ea* o!r 9 ! foll[+ ord]3-- #a/ r+1 or #a/ ord] ( col\rs3 ,black1 v fa9t blue1 brilliant :ite1 yell[1 orange1 r$4 #bnd r+3 ,d>k purple1 or r violet1 blue1 a v imp]fect yell[ gre51 vivid yell[1 crimson r$4 #crd r+3 ,purple1 blue1 ri* grass gre51 f9e yell[1 p9k1 crimson4 #d? r+3 ,dull bluei% gre51 pale yell[i% p9k1 r$4 #e? r+3 ,pale bluei% gre51 :ite1 p9k4 #f? r+3 ,pale blue gre51 pale p9k4 #g? r+3 ,v pale bluei% gre51 v pale p9k4 ,aft] ! sev5? ord] ! col\rs become too fa9t to be di/+ui%$4 ,! r+s decrease 9 bread?1 & ! col\rs become m cr[d$ toge!r1 z !y rec$e f ! c5tre4 ,:5 ! light is homog5e\s1 ! r+s are broade/ 9 ! r$1 & decrease 9 bread? ) e successive col\r ( ! spectrum to ! violet4 ,,note #bjj1 p4 #agb4 ,! absolute ?ickness ( ! film ( air betwe5 ! glasses is f\nd z foll[s3--,let ,a ,f ,b ,c1 fig4 #ei1 be ! section ( a l5s ly+ on a plane surface or plate ( glass ,p ,p1 se5 edgewise1 & let ,e ,c be ! diamet] ( ! sph]e ( :i* ! l5s is a segm5t4 ,if ,a ,b be ! diamet] ( any "o ( ,newton's r+s1 & ,b ,d p>allel to ,c ,e1 !n ,b ,d or ,c ,f is ! ?ickness ( ! air produc+ x4 ,e ,c is a kn[n quantity2 & :5 ,a ,b1 ! diamet]1 is measur$ ) compasses1 ,b ,d or ,f ,c c be comput$4 ,newton f\nd t ! l5g? ( ,b ,d1 correspond+ to ! d>ke/ "p ( ! fir/ r+1 is ! #ih1jjj? "p ( an in* :5 ! rays fall p]p5dicul>ly on ! l5s1 & f ?is he d$uc$ ! ?ickness correspond+ to ea* col\r 9 ! sy/em ( r+s4 ,by pass+ ea* col\r ( ! sol> spectrum 9 succession ov] ! l5ses1 ,newton also det]m9$ ! ?ickness ( ! film ( air correspond+ to ea* col\r1 f ! bread? ( ! r+s1 :i* are always ( ! same col\r ) ! homog5e\s light4 ,illu/ration3 ,fig4 #ei4 ,,note #bja1 p4 #agd4 ,! focal l5g? or di/ance ( a l5s is ! di/ance f its c5tre to ! po9t ,f1 fig4 #fj1 9 :i* ! refract$ rays meet4 ,let ,l ,l be a l5s ( v %ort focal di/ance fix$ 9 ! w9d[-%utt] ( a d>k room4 ,a sunbeam ,s ,l ,l pass+ ?r\gh ! l5s w be br\ght to a focus 9 ,f1 :5ce x w div]ge 9 l9es ,f ,c1 ,f ,d1 & w =m a circul> image ( light on ! opposite wall4 ,suppose a %eet ( lead1 hav+ a small p9-hole pi]c$ ?r\gh x1 to be plac$ 9 ?is beam2 :5 ! p9-hole is view$ f beh9d ) a l5s at ,e1 x is surr\nd$ ) a s]ies ( col\r$ r+s1 :i* v>y 9 appe>ance ) ! relative positions ( ! p9-hole & eye ) reg>d to ! po9t ,f4 ,:5 ! hole is ! #cj? ( an in* 9 diamet] & at ! di/ance ( #f-a_/b feet f ,f1 :5 view$ at ! di/ance ( #bd in*es1 !re are sev5 r+s ( ! foll[+ col\rs3-- #a/ ord]3 ,:ite1 pale yell[1 yell[1 orange1 dull r$4 #bnd ord]3 ,violet1 blue1 :iti%1 gre5i% yell[1 f9e yell[1 orange r$4 #crd ord]3 ,purple1 indigo blue1 gre5i% blue1 brilliant gre51 yell[ gre51 r$4 #d? ord]3 ,bluei% gre51 bluei% :ite1 r$4 #e? ord]3 ,dull gre51 fa9t bluei% :ite1 fa9t r$4 #f? ord]3 ,v fa9t gre51 v fa9t r$4 #g? ord]3 ,a trace ( gre5 & r$4 ,illu/ration3 ,fig4 #fj4 ,illu/ration3 ,fig4 #fa4 ,illu/ration3 ,fig4 #fb4 ,,note #bjb1 p4 #age4 ,let ,l ,l1 fig4 #fa1 be ! section ( a l5s plac$ 9 a w9d[-%utt]1 ?r\gh :i* a v small beam ( light ,s ,l ,l passes into a d>k room1 & comes to a focus 9 ,f4 ,if ! edge ( a knife ,k ,n be held 9 ! beam1 ! rays b5d away f x 9 hyp]bolic curves ,k r1 ,k r1 c41 in/ead ( com+ directly to ! scre5 9 ! /raight l9e ,k ,e1 :i* is ! b\nd>y ( ! %ad[4 ,z ^! b5d+ rays arrive at ! scre5 9 diff]5t /ates ( undulation1 !y int]f]e1 & =m a s]ies ( col\r$ fr+es1 r r1 c41 along ! edge ( ! %ad[ ,k ,e ,s ,n ( ! knife4 ,! fr+es v>y 9 bread? ) ! relative di/ances ( ! knife-edge & scre5 f ,f4 ,,note #bjc1 p4 #agg4 ,fig4 #dc repres5ts ! ph5om5a 9 "q1 :]e ,s ,s is ! surface1 & ,i ! c5tre ( incid5t waves4 ,! reflect$ waves are ! d>k l9es return+ t[>ds ,i1 :i* are ! same z if !y _h orig9at$ 9 ,c on ! o!r side ( ! surface4 ,,note #bjd1 p4 #ahj4 ,fig4 #fb repres5ts a prismatic cry/al ( t\rmal9e1 ^: axis is ,a ,x4 ,! slices t are us$ = pol>is+ light are cut p>allel to ,a ,x4 ,,note #bje1 p4 #aha4 ,d\ble refraction4 ,if a p5cil ( light ,r r1 fig4 #fc1 falls ^u a rhomboh$ron ( ,icel& sp> ,a ,b ,x ,c1 x is sep>at$ into two equal p5cils ( light at r1 :i* are refract$ 9 ! directions r ,o1 r ,e3 :5 ^! arrive at ,o & ,e !y are aga9 refract$1 & pass into ! air 9 ! directions ,o o1 ,e o1 p>allel to "o ano!r & to ! incid5t ray ,r r4 ,! ray r ,o is refract$ accord+ to ! ord9>y law1 :i* is1 t ! s9es ( ! angles ( incid5ce & refraction be> a con/ant ratio to "o ano!r 7see ,note #ahd71 & ! rays ,r r1 r ,o1 ,o o1 are all 9 ! same plane4 ,! p5cil r ,e1 on ! contr>y1 is b5t aside out ( t plane1 & its refraction does n foll[ ! con/ant ratio ( ! s9es2 r ,e is !re=e call$ ! extraord9>y ray1 & r ,o ! ord9>y ray4 ,9 consequ5ce ( ?is bisection ( ! light1 a spot ( ink at ,o is se5 d\ble at ,o & ,e1 :5 view$ f r ,i2 & :5 ! cry/al is turn$ r\nd1 ! image ,e revolves ab\t ,o1 :i* rema9s /ation>y4 ,illu/ration3 ,fig4 #fc4 ,,note #bjf1 p4 #ahb4 ,bo? ( ! p>allel rays ,o o & ,e o1 fig4 #fc1 are pol>is$ on leav+ ! d\bly refract+ cry/al1 & 9 bo? ! p>ticles ( light make _! vibrations at "r angles to ! l9es ,o o1 ,e o4 ,9 ! "o1 h[ev]1 ^! vibrations lie1 = example1 9 ! plane ( ! horizon1 :ile ! vibrations ( ! o!r lie 9 ! v]tical plane p]p5dicul> to ! horizon4 ,,note #bjg1 p4 #ahc4 ,if light be made to fall 9 v>i\s directions on ! natural faces ( a cry/al ( ,icel& sp>1 or on faces cut & poli%$ artificially1 "o direction ,a ,x1 fig4 #fc1 w be f\nd1 along :i* ! light passes )\t be+ sep>at$ into two p5cils4 ,a ,x is ! optic axis4 ,9 "s sub/ances !re are two optic axes =m+ an angle ) ea* o!r4 ,! optic axis is n a fix$ l9e1 x only has a fix$ direction2 = if a cry/al ( ,icel& sp> be divid$ into small] cry/als1 ea* w h its optic axis2 b if all ^! pieces be put toge!r aga91 _! optic axes w be p>allel to ,a ,x4 ,e l9e1 !re=e1 )9 ! cry/al p>allel to ,a ,x is an optic axis2 b z ^! l9es h all ! same direction1 ! cry/al is /ill said to h b "o optic axis4 ,,note #bjh1 p4 #ahd4 ,if ,i ,c1 fig4 #dh1 be ! incid5t & ,c ,s ! reflect$ rays1 !n ! p>ticles ( pol>is$ light make _! vibrations at "r angles to ! plane ( ! pap]4 ,,note #bji1 p4 #ahd4 ,let ,a ,a1 fig4 #dh1 be ! surface ( ! reflector1 ,i ,c ! incid5t & ,c ,s ! reflect$ rays2 !n1 :5 ! angle ,s ,c ,b is #eg1 & consequ5tly ! angle ,p ,c ,s equal to #cc1 ! black spot w be se5 at ,c by an eye at ,s4 ,,note #baj1 p4 #ahe4 ,let ,a ,b1 fig4 #dh1 be a reflect+ surface1 ,i ,c ! incid5t & ,c ,s ! reflect$ rays2 !n1 if ! surface be plate-glass1 ! angle ,s ,c ,b mu/ be #eg1 9 ord] t ,c ,s may be pol>is$4 ,if ! surface be cr[n-glass or wat]1 ! angle ,s ,c ,b mu/ be #ef #ee = ! fir/1 & #ec #aa = ! second1 9 ord] to give a pol>is$ ray4 ,,note #baa1 p4 #ahf4 ,a pol>is+ app>atus is repres5t$ 9 fig4 #fd1 :]e ,r r is a ray ( light fall+ on a piece ( glass r at an angle ( #eg3 ! reflect$ ray r s is !n pol>is$1 & may be view$ ?r\gh a piece ( t\rmal9e 9 s1 or x may be receiv$ on ano!r plate ( glass1 ,b1 ^: surface is at "r angles to ! surface ( r4 ,! ray r s is aga9 reflect$ 9 s1 & comes to ! eye 9 ! direction s ,e4 ,! plate ( mica1 ,m ,i1 or ( any sub/ance t is to be exam9$1 is plac$ betwe5 ! po9ts r & s4 ,illu/ration3 ,fig4 #fd4 ,,note #bab1 p4 #ahg4 ,9 ord] to see ^! figures1 ! pol>is$ ray r s1 fig4 #fd1 mu/ pass ?r\gh ! optic axis ( ! cry/al1 :i* mu/ be held z ne> z possible to s on "o side1 & ! eye plac$ z ne> z possible to s on ! o!r4 ,fig4 #fe %[s ! image =m$ by a cry/al ( ,icel& sp> :i* has "o optic axis4 ,! col\rs 9 ! r+s are exactly ! same ) ^? ( ,newton's r+s giv5 9 ,note #aii1 & ! cross is black4 ,if ! sp> be turn$ r\nd its axis1 ! r+s suff] no *ange2 b if ! t\rmal9e ?r\gh :i* x is view$1 or ! plate ( glass1 ,b1 be turn$ r\nd1 ?is figure w be se5 at ! angles #j1 #ij1 #ahj1 & #bgj ( its revolution4 ,b 9 ! int]m$iate po9ts1 t is1 at ! angles #de1 #ace1 #bbe1 & #cae1 ano!r sy/em w appe>1 su* z repres5t$ 9 fig4 #ff1 :]e all ! col\rs ( ! r+s are complem5t>y to ^? ( fig4 #fe1 & ! cross is :ite4 ,! two sy/ems ( r+s1 if sup]pos$1 w\ld produce :ite light4 ,illu/ration3 ,fig4 #fe4 ,illu/ration3 ,fig4 #ff4 ,,note #bac1 p4 #ahh4 ,saltpetre1 or nitre1 cry/allises 9 six-sid$ prisms hav+ two optic axes incl9$ to "o ano!r at an angle ( #e4 ,a slice ( ?is sub/ance ab\t ! #f? or #h? ( an in* ?ick1 cut p]p5dicul>ly to ! axis ( ! prism1 & plac$ v ne> to s1 fig4 #fd1 s t ! pol>is$ ray r s may pass ?r\gh x1 exhibits ! sy/em ( r+s repres5t$ 9 fig4 #fg1 :]e ! po9ts ,c & ,c m>k ! position ( ! optic axes4 ,:5 ! plate ,b1 fig4 #fd1 is turn$ r\nd1 ! image *anges successively to ^? giv5 9 figs4 #fh1 #fi1 & #gj4 ,! col\rs ( ! r+s are ! same ) ^? ( ?9 plates1 b !y v>y ) ! ?ickness ( ! nitre4 ,_! bread? enl>ges or dim9i%es also ) ! col\r1 :5 homog5e\s light is us$4 ,illu/ration3 ,fig4 #fg4 ,illu/ration3 ,fig4 #fh4 ,illu/ration3 ,fig4 #fi4 ,illu/ration3 ,fig4 #gj4 ,illu/ration3 ,fig4 #ga4 ,,note #bad1 p4 #ahi4 ,fig4 #ga repres5ts ! appe>ance produc$ by plac+ a slice ( rock cry/al 9 ! pol>is$ ray r s1 fig4 #fd4 ,! uni=m col\r 9 ! int]ior ( ! image dep5ds ^u ! ?ickness ( ! slice2 b :atev] t col\r may be1 x w alt]nately atta9 a maximum brightness & vani% ) ! revolution ( ! glass ,b4 ,x may be obs]v$1 t ! two k9ds ( qu>tz1 or rock cry/al1 m5tion$ 9 ! text1 are comb9$ 9 ! ame?y/1 :i* consi/s ( alt]nate lay]s ( "r-h&$ & left-h&$ qu>tz1 ^: planes are p>allel to ! axis ( ! cry/al4 ,,note #bae1 p4 #aic4 ,suppose ! major axis ,a ,p ( an ellipse1 fig4 #ah1 to be inv>iable1 b ! exc5tricity ,c ,s cont9ually to dim9i%1 ! ellipse w\ld bulge m & m2 & :5 ,c ,s vani%$1 x w\ld become a circle ^: diamet] is ,a ,p4 ,aga91 if ! exc5tricity 7 cont9ually to increase1 ! ellipse w\ld be m & m flatt5$ till ,c ,s 0 equal to ,c ,p1 :5 x w\ld become a /raight l9e ,a ,p4 ,! circle & /raight l9e are !re=e ! limits ( ! ellipse4 ,,note #baf1 p4 #aid4 ,! col\r$ r+s are produc$ by ! int]f]5ce ( two pol>is$ rays 9 diff]5t /ates ( undulation1 on ! pr9ciple expla9$ = common light4 ,,note #bag1 p4 #bbe4 ,accord+ to ,mr4 ,j\le1 t heat is produc$ by motion1 & t x is equival5t to x1 ,mr4 ,?ompson ( ,glasg[ inve/igates f :5ce ! sun d]ives 8 heat1 s9ce he %[s t nei!r combu/ion nor 8 primitive heat c\ld h suppli$ ! wa/e dur+ #fjjj ye>s4 ,he concludes t ! sol> heat is ma9ta9$ by myriads ( m9ute bodies t are revolv+ at ! edge ( 8 d5se nebulosity or atmosph]e1 "s ( :i* are (t5 se5 by u z fall+ />s4 ,^!1 vaporiz$ by 8 heat1 & drawn by 8 attraction1 meet ) int5se resi/ance on ent]+ ! sol> atmosph]e z a %[] ( meteoric ra92 ?r\gh x !y desc5d 9 spiral l9es to ! sun's surface1 produc+ enorm\s heat by friction dur+ _! fall1 & s]v+ = fuel on _! arrival4 ,,note #bah1 p4 #beb4 ,! class ,cryptogamia conta9s ! f]ns1 mosses1 funguses1 & sea-we$s2 9 all ( :i* ! p>ts ( ! fl[]s are 9 g5]al too m9ute to be evid5t4 ,,note #bai1 p4 #bed4 ,zoophytes are ! animals :i* =m madrepores1 corals1 sponges1 c4 ,,note #bbj1 p4 #bed4 ,! ,saurian tribe are creatures ( ! crocodile & liz>d k9d4 ,,note #bba1 p4 #bff4 ,if heat f a non-lum9\s s\rce be pol>is$ by reflection or refraction at r1 fig4 #fd1 ! pol>is$ ray r s w be /opp$ or transmitt$ by a plate ( mica ,m ,i1 "u ! same circum/ances t x w\ld /op or transmit light2 & if heat 7 visible1 images analog\s to ^? ( figs4 #fe1 #fg1 c41 w\ld be se5 at ! po9t s4 ,,note #bbb1 pp4 #bge1 #cbi1 #ceg4 ,! foot-p\nd1 or unit ( me*anical =ce e/abli%$ by ,mr4 ,j\le1 is ! =ce t w\ld raise "o p\nd weight ( matt] to ! height ( "o foot2 or x is ! impetus or =ce g5]at$ by a body ( "o p\nd weight fall+ by its gravitation ?r\gh ! height ( "o foot4 ,impetus1 vis viva1 or liv+ =ce1 is equal to ! mass ( a body multipli$ by ! squ>e ( ! velocity ) :i* x is mov+1 & is ! true measure ( "w or lab\r4 ,= if a weight be rais$ #aj feet1 x w require f\r times ! lab\r to raise an equal weight #dj feet4 ,if bo? ^! weights be all[$ to desc5d freely by _! gravitation1 at ! end ( _! fall _! velocities w be z #a to #b2 t is1 z ! squ>e roots ( _! heights2 b ! effect produc$ w be z _! masses multipli$ by #a & #d2 b ^! are ! squ>es ( _! velocities3 h5ce ! impetus or vis viva is z ! mass into ! squ>e ( ! velocity4 ,?us impetus is ! true measure ( ! lab\r employ$ to raise ! weights1 & ( ! effect ( _! desc5t1 & is entirely indep5d5t ( "t4 ,n[ heat is proportional to impetus1 & impetus is ! true measure ( lab\r4 ,9 p]cussion ! heat evolv$ is 9 proportion to ! =ce ( ! impetus1 & is ?us measur$ by lab\r4 ,travail is a ^w us$ 9 me*anics1 to express t "w done is equal to ! lab\r+ =ce employ$4 ,! "w done may be resi/ance ov]come or any o!r effect produc$1 :ile ! lab\r+ =ce may be a horse1 a /eam-eng9e1 w9d1 fall+ wat]1 c4 ,,note #bbc1 p4 #cac4 ,:5 a /ream ( positive electricity desc5ds f ,p to n1 fig4 #gb1 9 a v]tical wire at "r angles to ! plane ( ! horizontal circle ,a ,b1 ! negative electricity asc5ds f n to ,p1 & ! =ce ex]t$ by ! curr5t makes ! nor? pole ( a magnet revolve ab\t ! wire 9 ! direction ( ! arr[-heads 9 ! circumf]5ce1 & x makes ! s\? pole revolve 9 ! opposite direction4 ,:5 ! curr5t ( positive electricity fl[s upw>ds f n to ,p1 ^! effects are rev]s$4 ,illu/ration3 ,fig4 #gb4 ,illu/ration3 ,fig4 #gc4 ,,note #bbd1 p4 #cad4 ,fig4 #gc repres5ts a helix or coil ( copp] wire1 t]m9at$ by two cups conta9+ a little quicksilv]4 ,:5 ! positive wire ( a ,voltaic batt]y is imm]s$ 9 ! cup p1 & ! negative wire 9 ! cup n1 ! circuit is complet$4 ,! quicksilv] ensures ! connection betwe5 ! batt]y & ! helix1 by convey+ ! electricity f ! "o to ! o!r4 ,:ile ! electricity fl[s ?r\gh ! helix1 ! magnet ,s ,n rema9s susp5d$ )9 x1 b falls d[n ! mom5t x ceases4 ,! magnet always turns its s\? pole ,s t[>ds ,p1 ! positive wire ( ! batt]y1 & its nor? pole t[>ds ! negative wire4 ,,note #bbe1 p4 #caf4 ,a copp] wire coil$ 9 ! =m repres5t$ 9 fig4 #gc 0 ! fir/ & mo/ simple =m ( ! electro-dynamic cyl9d]4 ,:5 its extremities ,p & n are connect$ ) ! positive & negative poles ( a ,voltaic batt]y1 x becomes a p]fect magnet dur+ ! "t t a curr5t ( electricity is fl[+ ?r\gh x1 ,p & n be+ its nor? & s\? poles4 ,,note #bbf1 p4 #cdd4 ,x is to ,halley we are indebt$ = ! fir/ decl9ation *>t & ! !ory ( #d poles ( maximum magnetic int5sity1 s9ce confirm$ by obs]vation1 z well z ! e>lie/ au!ntic values ( ! magnetic elem5ts 9 ,london & ,/4 ,hel5a1 :]e he w5t on purpose to make obs]vations on t]re/rial magnetism4 ,s9ce t "t ,m4 ,gauss has =m$ *>ts ( ! magnetic l9es1 & publi%$ a !ory :i* v ne>ly repres5ts ! magnetic /ate ( ! globe4 ,! mass ( obs]vations daily mak+ by our cruiz]s & our ,gov]nm5t surveys 9 e "p ( ! e>? is enorm\s4 ,,note #bbg1 p4 #cfj4 ,9 fig4 #gd ! hyp]bola ,h ,p ,y1 ! p>abola p ,p ,r1 & ! ellipse ,a ,e ,p ,l1 h ! focal di/ance ,s ,p1 & co9cide ?r\gh a small space on ea* side ( ! p]ihelion ,p2 &1 z a comet is only visible :5 ne> ,p1 x is difficult to asc]ta9 :i* ( ! ?ree curves x moves 94 ,illu/ration3 ,fig4 #gd4 ,,note #bbh1 p4 #cfc4 ,9 fig4 #ge1 ,e ,a repres5ts ! orbit ( ,halley's comet1 ,e ,t ! orbit ( ! e>?1 & ,s ! sun4 ,! proportions are v ne>ly exact4 ,illu/ration3 ,fig4 #ge4 ,,note #bbi1 p4 #chb4 ,fig4 #gd repres5ts ! curves 9 "q4 ,x is evid5t t1 = ! same focal di/ance ,s ,p1 !re c be b "o circle & "o p>abola p ,p ,r1 b t !re may be an inf9ity ( ellipses betwe5 ! circle & ! p>abola1 & an inf9ity ( hyp]bolas ,h ,p ,y ext]ior to ! p>abola p ,p ,r4 ,,note #bcj1 p4 #chg4 ,let ,a ,b1 fig4 #bf1 be ! diamet] ( ! e>?'s orbit1 & suppose a /> to be se5 9 ! direction ,a ,s f ! e>? :5 at ,a4 ,six mon?s aft]w>ds1 ! e>?1 hav+ mov$ ?r\gh half ( its orbit1 w\ld arrive at ,b1 & !n ! /> w\ld appe> 9 ! direction ,b ,s1 if ! diamet] ,a ,b1 z se5 f ,s1 _h any s5sible magnitude4 ,b ,a ,b1 :i* is #aij1jjj1jjj ( miles1 does n appe> to be great] ?an ! ?ickness ( a spid]'s ?read1 z se5 f #fa ,cygni1 suppos$ to be ! ne>e/ ( ! fix$ />s4 ,,note #bca1 p4 #chi4 ,/>s ^: p>allax & prop] motions are kn[n4 ,"n ( ,/>4 ,prop] ,motion4 ,p>allax4 ,obs]v]s & ,comput]s4 ,c5tauri #cgfd #jib ,macle>4 44 #a ,h5d]son4 #fa ,cygni #eabc #jcgd ,bessel4 ,lyr #jcfd #jbjg ,pet]s4 ,sirius #abcd #jbcj ,h5d]son4 ,arcturus #bbfi #jabg ,pet]s4 ,pole ,/> #jjce #jajf ,pet]s4 ,capella 44 #jjdf ,pet]s4 ,la ,*evre #jdfa #jjdf ,pet]s4 ,great ,be> #jgdf #jacc ,pet]s4 ,! space run ?r\gh 9 "o second by ^! />s is !re=e-- ,c5tauri #e leagues ,h5d]son & ,macle>4 #fa ,cygni #aj leagues ,bessel4 ,lyr #b leagues ,/ruve & ,pet]s4 ,sirius #f leagues ,h5d]son & ,macle>4 ,arcturus #bb leagues ,pet]s4 ,pole ,/> league ,l9d5au & ,/ruve4 ,la ,*evre #ab leagues ,pet]s4 ,great ,be> #g leagues ,pet]s4 ,!re are ?ree great discrepancies 9 ! p>allax ( ! /> ,argel&] or #ahcj ,groombridge4 ,m4 ,otto ,/ruve makes x #jjcd1 :i* gives x a velocity ( #bea leagues p] second1 :ile ,m4 ,faye f9ds ! p>allax to be betwe5 #jjc & #jja1 :i* makes its velocity f #cj to #he leagues p] second4 ,^! are all m9imum velocities1 because we c only det]m9e on ! cele/ial vault a projection p]haps mu* =e%ort5$ ( ! real motions ( ! />s4 ,,note #bcb1 pp4 #cih1 #dja4 ,! foll[+ are ! b9>y sy/ems ^: orbits h be5 accurately det]m9$3-- ,"n ( ,/>4 ,p]iod 9 ,p]ihelion ,by :om ,comput$4 ,ye>s4 ,passage4 ,h]culis #cjbaf #ahcada ,madl]4 ,coron #dbejj #ahjgba ,madl]4 ,cancri #ehiaj #aheccg ,madl]4 ,urs ,majoris #ehbfb #ahagbe ,sav>y4 ,leonis #hbecc #ahdigf ,vill>ceaux4 ,ophiu*i #gchfb #ahjfhc ,encke4 #cjfb 9 ,dorpat #idgfe #ahcgda ,madl]4 ,catalogue ,bootis #aagadj #aggihh ,sir ,j4 ,h]s*el4 ,cygni #aghgjj #ahfbhg ,h9d4 ,virg9is #ahbabj #ahcfdc ,sir ,j4 ,h]s*el4 ,ca/or #bebffj #aheehc ,sir ,j4 ,h]s*el4 ,coron #gcfhhj #ahbfdh ,h9d4 ,virg9is #fcbbgj #afii ,h9d4 ,c5tauri #ggjjj #aheaej ,jacob4 ,orbit ( ,virg9is4 ,p]ihelion passage #ahcfdj ,incl9ation #bg #cf ,position ( asc5d+ ,node #ai #g ,angle betwe5 l9e ( ,nodes & #bie #ac ,apsides ,exc5tricity #jhgid ,p]iod 9 ye>s #ahdec ,orbit ( ,h]culis4 ,p]ihelion passage #ahcjef ,incl9ation #adj #ci ,position ( asc5d+ ,node #bag #ad ,angle betwe5 l9e ( ,nodes & ,apsides #bffec ,ecc5tricity #jdcha ,p]iod 9 ye>s #cgba ,comput$ by ,j4 ,flet*]1 ,esq41 #ahec4 ,,note #bcc1 p4 #djc4 ,! mass is f\nd 9 ! mann] expla9$ 9 ! text2 b ! me?od ( comput+ ! di/ance ( ! /> may be made m cle> by :at foll[s4 ,?\gh ! orbit ( ! satellite /> is really & app>5tly elliptical1 let x be repres5t$ by ,c ,d ,o1 fig4 #ad1 = ! sake ( illu/ration1 ! e>? be+ 9 d4 ,x is cle> t1 :5 ! /> moves ?r\gh ,c ,d ,o1 its light w take long] 9 com+ to ! e>? f ,o ?an f ,c1 by ! :ole "t x employs 9 pass+ ?r\gh ,o ,c1 ! bread? ( its orbit4 ,:5 t "t is kn[n by obs]vation1 r$uc$ to seconds1 & multipli$ by #aij1jjj1 :i* is ! numb] ( miles light d>ts ?r\gh 9 a second1 ! product w be ! bread? ( ! orbit 9 miles4 ,f ?is ! dim5sions ( ! ellipse w be obta9$ by ! aid ( obs]vation2 ! l5g? & position ( any diamet] z ,s p may be f\nd2 & z all ! angles ( ! triangle d ,s p c be det]m9$ by obs]vation1 ! di/ance ( ! /> f ! e>? may be comput$4 ,,note #bcd1 p4 #dje4 ,! mean results ( ,,mm4 ,argel&]1 ,otto ,/ruve1 & ,luhndahl = />s 9 ! nor!rn hemisph]e & ! epo* #agij1 places ! po9t to :i* ! sun is t5d+ 9 #bei #e ( "r asc5sion & #ee #bc ( nor? pol> di/ance4 ,mr4 ,gallaway comput$ f />s 9 ! s\!rn hemisph]e1 at ! same epo*1 ! po9t to h be5 9 #bfj #a "r asc5sion & #ee #cg nor? pol> di/ance1 results ne>ly id5tical1 ?\gh f v diff]5t data4 ,,note #bce1 p4 #dad4 ,"o ( ! globul> clu/]s m5tion$ 9 ! text is repres5t$ 9 fig4 #a1 plate #h4 ,! />s are gradually cond5s$ t[>ds ! c5tre1 :]e !y run toge!r 9 a blaze4 ,! m cond5s$ "p is project$ on a gr\nd ( irregul>ly scatt]$ />s1 :i* fills ! :ole field ( ! telescope4 ,!re are few />s ne> ?is clu/]4 ,,note #bcf1 p4 #dbj4 ,plate #h %[s five nebul z se5 9 ,sir ,john ,h]s*el's #bj-;feet telescope4 #a4 ,an enorm\s r+ se5 obliquely ) a d>k c5tre & a small /> at ea* extremity4 #b4 ,! r+ 9 ! con/ellation ,lyra4 #c4 ,! dumb-bell nebula 9 ,vulpicula4 #d4 ,! spiral nebula or bro!r sy/em 9 ! #bj-;feet telescope4 #e4 ,a sp9dle-%ap$ nebula4 ,plate #i repres5ts "s ( ! same objects z se5 by ,"l ,rosse4 #a4 ,nebula 9 ! girdle ( ,&rom$a4 #b4 ,! circul> nebula ( ,lyra4 #c4 ,! dumb-bell nebula 9 ,vulpicula4 ,! spiral nebul ( #ea ,messi]1 z se5 by ,"l ,rosse1 #a 9 plate #aj1 repres5ts fig4 #d ( plate #h2 & fig4 #b 9 ! same plate is "p ( ! great nebula 9 ,orion1 = ! :ole has nev] be5 se51 on acc\nt ( extreme remot5ess4 ,,note #bcg1 pp4 #cb1 #dbg4 ,! motion ( ! e>? is visibly prov$ by ,m4 ,f\cault's exp]im5ts4 ,if a p5dulum be left to oscillate q freely1 ! =ces produc+ ! oscillations be+ 9 ! v]tical plane1 !re is no cause t c produce an absolute *ange 9 its position ) reg>d to space2 b ! motion ( ! e>? *anges ! position ( a spectator ) respect to ! v]tical plane1 & he ref]s 8 own motion to x1 :i* seems gradually to turn away f its position1 precisely z a p]son 9 a boat ref]s 8 own motion to t ( ! l&1 & ?us ! motion ( ! e>? is truly & visibly prov$4 ,,index4 ,ab]de51 high wat] at1 #id4 ,absorption1 influ5ce (1 on temp]ature1 #bci2 diff]5ce ( sea & l& 9 p[] (1 #bdb2 gradually decreas+1 9 transmission ( radiant heat1 #bei2 ( radiant heat1 v>y+ ) sub/ances1 #bfh2 a transf] ( =ce1 #bge1 #bgf4 ,accel]ation ( ! moon's mean motion1 #cg1 #ch4 ,adams1 ,mr41 p]turbation 9 ,uranus's motion comput$ by1 #bb2 discov]y ( ,neptune1 #fb4 ,arolites1 !ory (1 #dbj1 #dbc4 ,africa1 tidal wave pass+1 #id2 mean annual equatorial temp]ature 91 #bde2 indig5\s productions (1 #bdi1 #bej4 ,air1 comp>ative velocity ( light 9 wat] &1 #bjb4 ,see ,atmosph]e4 ,airy1 ,pr(essor1 p]iodic inequality 9 ! sol> sy/em work$ out by1 #bf2 ph5om5on obs]v$ by1 dur+ an eclipse1 #da2 mass ( ,jupit] asc]ta9$ by1 #ee2 exp]im5ts asc]ta9+ its d5sity1 #eg2 a/ronomical tables improv$ by1 #fc2 discov]ies 9 pol>ization ( light1 #aib1 #aic4 ,aldeb>an1 an optically d\ble />1 #dja4 ,aleutian ,isl&s1 !1 vegetation (1 #beb4 ,alex&ria1 arc ( ! m]idian measur$ betwe5 ,sy5e &1 #di4 ,alg1 di/ricts ( di/9ct species (1 #beb2 banks (1 9 ! ,atlantic1 #bec4 ,algol1 fluctuations 9 lu/re (1 #cij1 #cia4 ,alhaz51 effects ( refraction obs]v$ by1 #aee4 ,alkalies1 resolv$ into metallic oxides1 #cjg4 ,alpha ,ant>is1 8,coal ,sacks0 betwe5 ,c5tauri &1 #chf4 ,alpha ,aquil1 an optically d\ble />1 #dja4 ---- ,c5tauri1 ! p>allax (1 #ed2 its rank1 #chd2 ! ,milky ,way ne>1 #chf2 p>allax1 z det]m9$ by ,h5d]son & ,macle>1 #chg2 di/ance f ! sun1 #chh2 orbit & mass (1 #cii1 #djj2 col\r1 #dja2 am\nt ( light emitt$ by1 #djd2 rate ( its prop] motion1 #djd1 #dje2 globul> nebul\s clu/]1 #dad4 ---- ,crucis1 zone ( />s pass+ ?r\gh1 #che2 zone betwe5 ,args &1 #cij2 nebul\s clu/] r\nd1 #dae4 ---- ,lyr1 ! pol> /> ( ! nor!rn hemisph]e1 #hb2 p>allax (1 #chh2 di/ance f ! sun1 #chi2 an optically d\ble />1 #djj2 am\nt ( light emitt$ by1 #djd4 ---- ,orionis1 a v>iable />1 #cic1 #cid4 ,alum1 exp]im5ts on ! cry/allization (1 #ajf1 #ajg2 heat transmitt$ ?r\gh1 #bfa1 #bfb4 ,amazons1 ! riv] (1 di/ance f its m\? :]e tides are p]ceptible1 #ih2 area occupi$ by =e/s on1 #bdc4 ,am]ica1 c\rse ( ! tidal wave along its coa/s1 #ic1 #id2 mean annual equatorial temp]ature 91 #bde2 sep>ation ( iso!rmal l9es 9 high latitudes1 ib42 numb] ( kn[n species ( plants indig5\s 91 #bdi2 numb] ( species ( trees1 #beb2 %oot+ />s ov] ! cont95t (1 #dba4 ----1 ,s\?1 area ( c\ntry rais$ by an e>?quake 91 #bcd4 ,ampre1 ,m41 8 discov]y 9 electricity1 #caf2 !ory ( magnetism1 #cag1 #cah2 exp]im5t te/+ 8 !ory1 #cai1 #cbj4 ,analysis1 b\ndless dom9ion (1 #dbg1 #dbh4 ,&es1 !1 proportion (1 to ! e>?'s mass1 #f2 increas+ r>ity ( ! air exp]i5c$ 9 asc5d+1 #aah4 ,&rom$a1 nebula 91 #dac2 nebul\s region (1 #dag4 ,ang/rm1 ! electric sp>k def9$ by1 #cjc4 ,animals1 specific div]sity (1 laws regulat+ _! di/ribution1 #bed1 #bee4 ,annual equation1 !1 ( ! moon1 #ce1 #cf4 ---- v>iations 9 mean values ( ! magnetic elem5ts1 #cdc4 ,annul> nebul1 #dji2 9 ! nor!rn hemisph]e1 #daj1 #daa4 ,ant>ctic ,ocean1 tidal wave ris+ 9 #ic2 p]iod ( its passage to ! ,?ames1 #id2 dep? ( ! /ratum ( con/ant temp]ature 91 #aja2 depression ( ! b>omet] obs]v$ 91 #abj4 ,antilles ,isl&s1 hurricanes beg9n+ at1 #abf4 ,ant9ori1 ,cav41 exp]im5ts (1 9 electricity1 #ccc4 ,ant9\s1 comet obs]v$ 9 ! con/ellation (1 #cgb2 ! ,milky ,way betwe5 ,orion &1 #chf4 ,anti!sis1 ! g5]al "* ( magnetism1 #cci4 ,aphelion ( a planet's pa? def9$1 #af4 ,apogee1 sol>1 its co9cid5ce ) ! sol/ices1 #hf1 #hg4 ,april1 #ahcc1 disappe>ance ( ,saturn's r+s1 #fg2 app>5t & mean "t co9cid+ 91 #hd4 ,apsides ( an axis def9$1 #i2 direct1 v>iable motion (1 #ad2 cause ( _! advance1 or recession1 #af4 ,apures1 ! mission ( !1 ,humboldt's obs]vations on s\nd at1 #ace4 ,aque\s vap\r1 proportion (1 9 ! atmosph]e1 #aag4 ,ara1 nebula 91 #dad4 ,arabian ,gulf1 !1 monsoons bl[+ ov]1 #abd4 ,arabs1 !1 _! obs]vations on planet>y irregul>ities1 #bf2 lun> eclipses obs]v$ by1 #ch2 _! division ( "t1 #he2 ! p5dulum us$ z a measure ( "t by1 #ij4 ,arago1 ,franois1 exp]im5t by1 9 pro( ( ! undulatory !ory ( light1 #bjj2 decisive exp]im5t sugge/$ by1 #bjb2 obs]vations 9 photography1 #bac2 obs]vations on ! moon's atmosph]e1 #bbf2 increase ( temp]ature bel[ ! e>?'s surface calculat$ by1 #bcj2 sl[ communication ( temp]ature f ! e>?1 obs]v$1 #bdd2 s\rce ( magnetism discov]$1 #ccj2 !ory ( 8 magnetic exp]im5ts1 #ccb2 div]g5t flames ( a comet describ$ by1 #cfd2 8 treatise on comets1 #cfh2 nature ( comet's light det]m9$ by1 #chj1 #cha2 numb]s ( comets comput$1 #cha1 #chb2 rem>k (1 on fix$ />s1 #dje4 ,arc1 ! ,voltaic1 #cjc-cje4 ,arcet1 ,m4 d'1 vibration ( fibres ( ! ret9a accord+ to1 #agh4 ,ar*]1 ,scott1 /imulus giv5 to photography by1 #bjg4 ,arcs ( ! m]idian1 mode ( measur+1 #dg4 ,arctic ,sea1 dep? ( ! zone ( con/ant temp]ature1 #aja4 ---- regions1 vegetation f\nd 91 #bdi4 ,arcturus1 comet be>+ comp>ison )1 #cgi2 rank (1 #chd4 ,areas1 describ$ by ! radii vectores ( planets1 a te/ ( di/urb+ =ces1 #aj2 unequable description (1 #ae4 ,argel&]1 ,m41 p]iod ( a comet calculat$ by1 #cgj2 8 mode ( e/imat+ di/ance ( fix$ />s1 #chi2 p]iods ( fluctuation 9 />s comput$ by1 #cij1 #cia2 sun's motion prov$1 #dje4 ,arg5t9e prep>ations 9 photography1 *emical en]gy v>y+ )1 #bjg1 #bjh2 *anges effect$ by wa%+ ) alkalies1 #baj1 #baa4 ,argo1 v>iable /> 91 #cic4 ,aries1 season ( ! sun's entrance into1 9 ,hipp>*us' age1 #hj4 ,ars5iate ( soda1 its cry/als1 #aji4 ,artesian wells1 mode ( s9k+1 orig9 ( ! "n1 #bcj4 ,asia1 indig5\s productions (1 #bdi4 ,assyrians1 !1 division ( "t by1 #he4 ,a/ronom]s1 fruits ( _! lab\rs1 #c2 "q /ill to be resolv$ by1 #bd2 t]re/rial orbit diff]5tly measur$ by1 #cf4 ,a/ronomical di/ances1 me?od ( measur+1 #dc2 tables1 me?od ( =m+1 #eh-fd4 ,a/ronomy1 its rank 9 ! physical sci5ces1 an important (fice (1 #a2 /udies necess>y to ! /udy (1 #b2 ! key to div]s problems 9 physical sci5ce1 #c2 ! two greate/ discov]ies 91 #bc2 ! ?ree dep>tm5ts (1 #eh2 /&>ds = measurem5t af=d$ by1 #hc2 application (1 to *ronology1 #hg-hi2 furni%+ /&>ds ( weights & measures1 #hi1 #ij2 atmosph]ic effects connect+ ! laws ( molecul> attraction )1 #ajb2 progress lately made by1 #dai1 #dbj4 ,atalanta1 diamet] (1 #ef4 ,atlantic ,ocean1 direction ( tidal waves 91 #ic2 conditions modify+ tides1 #id2 dep? (1 #if2 curr5ts1 #ajj2 orig9 ( hurricanes1 #abf2 sup]ficial temp]ature (1 #bdd2 di/9ct vegetation ( ! pol> bas91 #beb2 b$s ( alg 91 #bec2 meteors fall+ 91 #dba4 ---- telegraph1 #cbe1 #cbf2 t]re/rial magnetism di/urb+1 #cdf4 ,atmosph]e ( nebul\s />s1 #daa1 #dab4 ---- ( planets1 #bbf1 #bbg4 ---- ( ! sun1 its con/itution1 #db2 indications ( an absorptive surr\nd+ ! lum9\s1 #bac2 ! true1 #bbd4 ---- t]re/rial1 sol> rays b5t by1 9 lun> eclipses1 #dj2 influ5ce (1 9 sol> eclipses1 #da2 its analysis1 pressure on ! surface ( ! globe1 #aag2 =m (1 gradual decrease 9 d5sity ( its /rata1 #aag1 #aah2 influ5ce ( temp]ature on its d5sity1 #aai2 mean pressure (1 v>iable1 #abj2 ! m$ium convey+ s\nd1 #abi2 sympa!tic vibrations transmitt$ by1 #adg1 #adh2 its action on light1 falsify+ vision1 #aec2 ph5om5a produc$ by accid5tal *anges 9 its /rata1 #aee-aef2 effects ( increas$ d5sity 9 ! /ratum 9 ! horizon1 #aeg1 #aeh2 lun> heat absorb$ by1 #bbg2 cause ( ! cool] air 9 high] regions (1 #bdj1 #bda2 sun's heat modifi$ by1 #bdd2 action ( electricity 91 #bhd2 transmission ( electricity by induction1 #bhf2 p]iodical v>iations ( electricity 91 #bia2 accid5tal developm5ts ( electricity1 #bia1 #bib2 cause ( v>iations 9 its magnetism1 #cdd1 #cde2 nebul\s bodies made visible by1 #dba-dbc4 ,atmosph]ic air1 extreme ela/icity (1 #aje4 ---- pressure1 effect (1 on electricity1 #bhh4 ,atomic con/itution det]m9+ cry/all9e =ms1 #aji4 ,atoms1 qualities (1 det]m9+ ! nature ( sub/ances1 #aaj2 diff]5ces 9 weight (1 #aaa4 ,attraction1 modes (1 9 sph]es1 9 ! cele/ial bodies1 #d2 det]m9+ ! =ms ( planets1 #f2 det]m9+ ! motions ( planets1 #g2 sol>1 compell+ ! elliptical revolutions ( planets1 #h2 mutual1 ( planets1 complicat+ _! motions1 #aj2 int]f]5ce (1 di/urb+ ! motions ( heav5ly bodies1 #aa2 di/urbances f ! op]ation ( reciprocal1 #ac2 di/urbances f inequality (1 #ad2 ( satellites to prim>ies1 little di/urb$1 #bf2 di/urb+ =ce (1 9 sph]oids1 #bg2 its effects on ,jupit]'s satellites1 #bh2 sun's1 ( ! moon1 #cd2 pr9ciple modify+ ! e>?'s1 #cg2 local1 affect+ ! plumb-l9e1 #dh2 comp>ative =ce ( ! sun's1 #eg2 ( an ext]nal body affect+ a sph]oid1 #gi2 produc+ tides1 #ia1 #ib2 ( p>ticles ( matt]1 #ajc2 capill>y1 #aac2 produc+ annual atmosph]ic undulations1 #aba2 ! lun> atmosph]e affect$ by1 #bbf2 expansive =ce ( heat ov]com+1 #bga2 ( electricities1 #bhc2 de/ruction (1 produc+ electricity1 #bhd2 laws ( electrical1 #bhf-bhh2 modes (1 9 /atic & 9 voltaic electricity1 #cag2 action ( planet>y1 on comet's orbits1 #cfa-cfc2 range ( sol>1 #cfe4 ,aurora1 !1 affect+ ! compass1 #cab4 ,au/ralia1 evid5ce ( des]ts 9 ! int]ior (1 #abd2 species ( plants common to ,europe &1 #bea4 ,auv]gne1 temp]ature ( hot spr+s 91 #bca4 ,axes1 *ange 9 =m ( masses revolv+ r\nd1 #f4 ----1 major1 l5g? (1 9 orbits1 inv>iable1 #bj2 ( ! orbits ( ,jupit]'s satellites1 cause ( ! direct motion obs]v$ 91 #bh2 position (1 9 ! sol> sy/em1 #fe2 a nutation 9 planet>y1 #ff2 ( ! moon1 #fh1 #fi2 me*anical law affect+1 #gf4 ----1 optic1 ( cry/als1 #ahc4 ,axis1 great]1 ( ! e>?'s orbit1 p]iod ( its revolution1 #ch2 p]iod ( ! e>?'s revolution1 #eh2 excess ( ,jupit]'s equatorial ov] 8 pol>1 #ff2 ( rotation1 pro( ( its be+ inv>iable1 #gf1 #gg4 ----1 major1 ( a planet's orbit1 di/ance f ! sun measur$ by1 #h2 designation ( its extremities1 #i2 l5g? (1 det]m9+ ! =m ( ! orbit1 #aj2 p]iods ( its revolutions1 #ag2 l5g? (1 n p]man5tly *ang$1 #bj2 ,jupit]'s p]iodically dim9i%$1 ,saturn's increas$1 #bf2 ( ! sol> ellipse1 p]iod ( its revolution1 #hf4 ----1 magnecry/allic1 #cdi4 ,azores1 !1 iceb]gs rea*+1 #ajj4 ,babbage1 ,*>les1 8 !ory ( volcanic action1 #bce-bcg2 quotation f1 on ! nature ( =ce1 #cec4 ,bab9et1 ,m41 8 !ory ( d>k l9es obs]v$ 9 ! sol> spectrum1 #afc2 comet's light comput$ by1 #cei4 ,babylon1 eclipse obs]v$ at1 #cf4 ,bacon1 ,francis1 anticipation ( discov]y by1 #cb4 ,baily1 ,mr41 compression ( ! t]re/rial sph]oid calculat$ by1 #ej2 d5sity ( ! e>? det]m9$1 #eg2 fictiti\s antiquity ascrib$ to ,indian a/ronomical obs]vations1 #hh4 ,bali1 volcanic eruption 91 #bcc4 ,balloon1 r>ity ( ! air felt 9 a1 #aah2 obs]vations made f1 #aai4 ,baltic1 !1 a tideless sea1 #ih2 decreas$ atmosph]ic pressure on ! %ores (1 #abj4 ,b>l[1 ,mr41 obs]vations support+ 8 !ory ( electric curr5ts1 #cdf4 ,b>omet]1 !1 pr9ciples ( cohesion & attraction appli$ to ! con/ruction (1 #aac2 d5sity ( ! atmosph]e measur$ by1 #aag2 mean heights (1 v>y+ ) atmosph]ic d5sities1 #aah2 m\nta9 heights measur$ by1 #aai1 #abj2 atmosph]ic ph5om5a affect+1 #abj2 us$ to trace ! c\rse ( atmosph]ic waves1 #aba2 cause ( sudd5 fall 91 be=e hurricanes1 #abg2 refraction v>y+ )1 #aed4 ,b>r[1 ,cape1 obs]vations on magnetic /orms at1 #cde1 #cdf4 ,batt]y1 voltaic1 con/ruction (1 #bih1 #bii2 ,pr(essor ,daniell's improvem5ts1 #bii1 #cjj2 action (1 *>g$ ) wat]1 #cjj2 con/ant fl[ ( electricity obta9$ by means (1 #cab4 ----1 magnetic1 con/ruct$ by ,dr4 ,f>aday1 #cbd1 #cbe2 ,mr4 ,h5ley's magneto-electric1 #cbe2 ,atlantic telegraph1 #cbf2 /ructure (1 = l& telegraphs1 #cbh2 relation ( heat to p[] (1 #cbi2 !rmo-electric1 #ccc4 ,bat%a1 port (1 tides neutralis$ 91 #ii4 ,bayle1 comp>ative d5sity ( ! atmosph]e 9 int]planet>y space accord+ to 8 law1 #cef4 ,be>1 ,little1 !1 ! pol> /> 91 #hb4 ,becqu]el1 ,m4 ,e41 unexpla9$ photographic ph5om5on obs]v$ by1 #bac2 phosphoresc5t prop]ty 9 ! sol> spectrum discov]$1 #baf2 cause ( phosphoresc5ce1 #bag2 electricity excit$ by pressure1 #bhc2 light attribut$ to electricity by1 #bhd2 cause ( phosphoresc5ce inve/igat$1 #bif2 in/rum5t comp>+ int5sities ( electricities inv5t$1 #cjj2 cry/als =m$ by ag5cy ( electricity1 #cjh2 !rmo-electric batt]y con/ruct$ by1 #ccc2 effect ( atmosph]ic on t]re/rial magnetism e/imat$1 #cde4 ,beehive1 !1 a nebul\s />1 #dae4 ,b]>d1 ,m41 exp]im5ts (1 9 pol>iz+ heat1 #bfd4 ,b]l91 l9e ( co9cid5ce 9 temp]ature pass+ ?r\gh1 #bch4 ,b]ne1 increas+ temp]ature ( a des]t$ m9e 91 #bcj4 ,b]re1 ,dr41 photographic pictures p]fect$ by1 #bje4 ,bessel1 ,m41 8 calculations f measurem5ts ( arcs ( ! m]idian1 #dh2 calculation ( ! sun's mean app>5t diamet]1 #ef2 8 computation ( ! mass ( ,saturn's r+1 #fh2 dim9i%$ obliquity ( ! ecliptic obs]v$ by1 #ha2 p>allax calculat$1 #chi2 8 !ory ( ,sirius's irregul> motions1 #cib2 catalogue ( d\ble />s1 #cif2 mass ( #fa ,cygni f\nd by1 #djd4 ,beta ,lyr1 a v>iable />1 #cia2 nebula betwe5 ,lyr &1 #daj4 ,b5z5b]g1 ,m41 velocities ( fall+ />s comput$ by1 #dbc4 ,biela1 ,m41 date ( ! discov]y ( 8 comet1 #cfg2 possibility ( collision ) ! e>?1 #cfh2 pres5t & prospective planet>y influ5ce on1 #cfi2 becom+ two di/9ct bodies1 #cfi1 #cgj4 ,b9>y sy/ems ( />s1 #cie-djf4 ,see ,d\ble />s4 ,biot1 ,m41 8 asc5t 9 a balloon1 #aah2 exp]im5ts (1 on ! transmission ( s\nds ?r\gh pipes1 #acg2 liquids possess+ ! p[] ( circul> pol>ization discov]$ by1 #aij2 8 !ory ( circul> pol>ization1 #aia2 cause ( phosphoresc5ce 9 ! sol> spectrum inve/igat$ by1 #bag4 ,birds1 di/ribution ( di/9ct species (1 #bee4 ,birt1 ,mr41 atmosph]ic waves measur$ by1 #aba1 #abb4 ,bise1 9 ,switz]l&1 cause (1 #bdb4 ,bismu?1 its magnetic & electric prop]ties1 #cdg4 ,black ,sea1 !1 sc>cely affect$ by tides1 #ih4 ,bode1 ,b>on1 law (1 assum$ 9 comput+ ,neptune's position1 #fa2 fail+ 9 ! case ( ,neptune1 #fc4 ,bond1 ,mr41 satellite ( ,saturn discov]$ by1 #cb2 elliptical nebula resolv$1 #dac4 ,bonnyca/le1 ,capta91 phosphoresc5t ph5om5on obs]v$ by1 #bie1 #bif4 ,bonpl&1 ,m41 id5tical productions ( ! ,old & ,new ,_w f\nd by1 #bea4 ,botes1 nebul\s sy/em 91 #dag4 ,bore1 !1 ( ! ,hoogly1 its orig91 #id4 ,botanical di/ricts1 di/9ct1 ( ! globe1 #bea1 #beb4 ,botto1 ,m41 !rmo-electricity us$ 9 decomposition by1 #ccc4 ,b\gu]1 degrees ( ! m]idian measur$ by1 #dh4 ,b\ss+ault1 ,m41 dep? ( ! und]gr\nd /ratum ( con/ant heat calculat$ by1 #bbh4 ,b\v>d1 ,m41 atmosph]ic undulations e/imat$ by1 #aba4 ,bradley1 ,dr41 motion ( ! pole ( ! equator discov]$ by1 #hd2 8 tables ( refraction1 #aee4 ,brahm9s1 measurem5t ( "t by1 #he4 ,br&1 ,m41 obs]vation (1 on meteors1 #dbc4 ,brew/]1 ,sir ,david1 8 analysis ( ! sol> spectrum1 #afa2 exp]im5ts on rayless l9es1 #afc2 exp]im5ts on spectra ( flames1 #afd2 law discov]$ by1 det]m9+ angles ( pol>ization = light1 #ahc2 exp]im5ts on fluoresc5ce ( light1 #aig2 l9e ( co9cid5ce 9 temp]ature ( spr+s & ( ! atmosph]e det]m9$ by1 #bch2 temp]ature ( a pole ( maximum cold det]m9$1 #bde2 isogeo!rmal l9es det]m9$ by1 #bdf2 obs]vations on ! light ( fix$ />s1 #djb4 ,brighton1 ph5om5on caus$ by reflection obs]v$ f1 #aeg4 ,br9kley1 ,bi%op1 mass ( ! moon det]m9$ by1 #ef4 ,briti% ,*annel1 height ( tides 91 #ih4 ---- ,isles1 atmosph]ic wave pass+ ov]1 #aba4 ,brors51 ,m41 p]iods ( comets discov]$ by1 #cgj4 ,br[n1 ,dr4 ,rob]t1 peculi> vegetation f\nd by1 9 ,au/ralia1 #bea4 ,bu*an1 ,dr41 ph5om5on caus$ by reflection obs]v$ by1 #aeg4 ,cs>1 ,julius1 era comput$ f 8 reign1 #he4 ,cagni>d de la ,t\r1 ,m41 in/rum5t design$ by1 measur+ musical notes1 #adc4 ,calms produc$ by ! trade-w9ds1 #abb1 #abc4 ,calorific rays4 ,see ,rays ( heat4 ,calotype1 ! inv5tion (1 #bjd4 ,camelop>d1 nebul\s sy/em 91 #dag4 ,can>ies1 !1 vegetation (1 #beb4 ,can>y-glass1 fluoresc5ce ( light 91 #aif4 ,canc]1 ! calms (1 #abc2 ! tropic (1 m>k+ ! limit ( ! trade-w9ds1 #abf2 nebul\s clu/] 91 #dae4 ,canis ,major1 position (1 #cij4 ---- ,v5atica1 nebul\s sy/em 91 #dag4 ,capill>ity1 !ory (1 #aac2 =ces produc+1 #aad2 famili> examples (1 #aae2 curi\s ph5om5a1 #aae1 #aaf4 ,capricorn1 ! calms (1 #abc2 ! tropic (1 hurricanes *ang+ _! direction at1 #abf4 ,c>bon1 its p[]s contra/$ z a cry/al & z an opaque amorph\s sub/ance1 #cjb1 #cjc4 ,c>bonate ( lime4 ,see ,lime4 ,c>bonic oxide1 its con/itu5t p>ts1 #aaa4 ---- acid1 proportion (1 9 ! atmosph]e1 #aag4 ,c>d9al po9ts1 !1 position ( cont95tal masses ) reg>d to1 influ5c+ temp]ature1 #bdd4 ,c>ibbean ,isl&s1 hurricanes beg9n+ at1 #abf4 ,ca/or1 discov]$ by ,sir ,william ,h]s*el1 #cif4 ,cassiopeia1 /> appe>+ & vani%+ 91 #cib1 #cic4 ,categat1 !1 consequ5ce ( its n>r[ness1 #ih4 ,cau*y1 ,m41 data furni%$ by1 = inve/igation ( ! !ory ( light1 #bja4 ,cay5ne1 v>iation 9 l5g? ( ! p5dulum betwe5 ,p>is &1 #ea4 ,cele/ial bodies3 law ( _! mutual attraction1 #d2 ( ! sol> sy/em3 law det]m9+ _! attraction to ! sun1 #e2 problem to fix ! positions (1 on occurr5ce ( di/urbance 9 _! motions ?r\gh c\nt]act+ attractions1 #aa2 !ory ( _! mutual connection & dep5d5ce1 #bd2 mode ( f9d+ ! absolute di/ances (1 #dc2 di/ances (1 comput$ f _! p>allax1 #eb1 #ed2 app>5t position (1 affect$ by refraction1 #aec1 #aed2 app>5t inf9ity (1 #dbj4 ,c5taur1 position (1 #cij2 brilliant d\ble /> 91 #cii4 ,c5tral ,asia1 ! m\nta9s (1 _! asc5t by ,m>co ,polo1 #aah4 ,c5tre ( gravity4 ,see ,gravity4 ,c5trifugal =ce1 moon's motions modifi$ by1 #e2 influ5ce (1 on planet-=ms1 #f2 ret>d+ oscillations ( ! p5dulum1 #cb2 action (1 9 det]m9+ ! figure ( ! e>?1 #dd1 #de2 measurem5t ( its int5sity1 #di2 resolv$ into two =ces1 its action on ! sea1 #ajj4 ,c]es1 a/ronomical tables (1 #fc2 height ( h] atmosph]e1 #bbf2 comet ( #aggj revolv+ beyond ! orbit (1 #cfa4 ,cetus1 nebul\s pat*es cross+1 #dag4 ,*aldeans1 !1 mean longitude f\nd f obs]vations (1 #cf2 result ( comp>ison ( _! obs]vations ) mod]n1 #ch4 ,*allis1 ,pr(essor1 ,brew/]'s analysis ( light que/ion$ by1 #afa4 ,*>coal1 light produc$ by electricity f1 #cjb-cjc4 ,*>les ,v41 ! ,emp]or1 obs]vations on comets1 made 9 8 reign1 #cgj4 ,*audes ,aigues1 temp]ature (1 #bca4 ,*emical action ( rays ( ! sol> spectrum1 #bjc1 #bjg2 v>y+ maximum ( en]gy1 #bjh2 action v>y+ ) refrangibility1 #bji-bab2 action 9 lum9\s spectrum n cont9u\s1 #bac2 en]gy an indep5d5t prop]ty ( rays1 #bad2 prop]ties ( ! p>a!rmic rays1 #bai2 action ( light ma9ta9+ vegetation1 #bdi2 aff9ities ! s\rce ( ! p[] ( /eam1 #bgh2 ( electricity on oxyg51 #bhd2 elicit+ voltaic electricity1 #big1 #cjj2 voltaic electricity1 an ag5t 91 analysis1 #cjg1 #cjh4 ---- comb9ations1 !ory (1 #aaj2 inv>iable proportions (1 #aaa2 cohesive =ce induc+1 #aab2 produc+ combu/ion1 #bgj4 ---- =ce1 ! p[] (1 #aab4 ---- rays1 caus+ ! deposition ( dew1 #bfi4 ,*ile1 elevation ( l& by an e>?quake 91 #bcd4 ,*9a1 di/9ct flora (1 #bea4 ---- ,sea1 !1 monsoons bl[+ ov]1 #abd4 ---- ink1 pol>iz$ light reflect$ f1 #aic4 ,*9ese1 !1 obs]vations (1 on ! mean motions ( ,jupit] & ,saturn1 #be2 pro( ( _! e>ly /udy ( a/ronomy1 #hh2 decimal divisions us$ by1 #ij2 elem5ts ( comets comput$ f _! obs]vation1 #cfe2 comet ( #abfd record$ by1 #cgj4 ---- ,t>t>y1 h]b>ium collect$ 91 #bej1 #bea4 ,*ladni1 discov]y (1 9 musical sci5ce1 #ade4 ,*ri/ian era1 traces ( a/ronomical records be=e1 #cfe4 ,*romatype1 ! inv5tion (1 #bjf4 ,*ronology1 dep5d5t on a/ronomy1 #hg-hi4 ,*rysotype1 !1 col\r$ photographs obta9$ f1 #bjf4 ,circuit1 galvanic1 modes ( obta9+1 #ccb4 ,circul> arcs1 pr9ciple ) reg>d to _! s9es & cos9es1 a pl$ge = ! /ability ( ! sol> sy/em1 #bj4 ---- motion1 ratio ( =ces procur+1 #chb4 ---- orbits ( planets di/+ui%$ f elliptical1 #h2 ( satellites1 #bg4 ---- pol>ization ( light1 #ahi-aib2 ( heat1 #bff4 ,circumf]5ce ( ! e>?1 #di4 ,civil "t1 measure ( its p]iods1 #hc2 n precisely adju/$ to sol> revolutions1 #he4 ,clairaut1 p]iodic "t ( ,halley's comet comput$ by1 #cfb1 #cfc4 ,cleavages ( cry/als1 #aji2 position (1 affect+ ! int5sity ( magnetic action1 #cej4 ,climates1 planet>y1 #bbe1 #bbf2 cause ( ! diff]5t t]re/rial1 #bcg2 ph5om5a affect+1 #bci1 #bdj2 causes ( v>iety (1 #bdc1 #bdd2 mild]1 ( ! ,pol> ,ocean1 #bde1 #bdf2 l mean annual temp]atures n ensur+ l1 #bdf2 comp5sations ( irregul>ities1 #bdg4 ,clocks1 %[+ app>5t sid]eal "t1 #hc2 regulat$ to %[ decimal "t1 #hd2 irregul> action (1 correct$ by ! laws ( unequal expansion1 #bgb4 ,cl\ds1 circl+ ! belt ( equatorial calms1 #abc2 region (1 #abd2 electricity evolv$ f1 #bia-bib4 ,cloyne1 ,bi%op (1 8 calculation ( ! moon's mass1 #ef4 ,coal-measures1 tropical plants 91 #gb1 #gc2 age ( _! =mation1 #ge4 ,coal1 *emical =ce evolv$ f1 by combu/ion1 #bgh2 s\rce ( its combu/ible qualities1 #bgi1 #bhj4 8,coal ,sacks0 9 ! ,milky ,way1 #chf4 ,cohesion1 influ5ce (1 on matt]1 #aje2 ph5om5a aris+ f its =ce1 #ajf2 attraction (1 ov]come by ! expansive p[] ( heat1 #bga4 ,cohesive =ce1 prop]ties ( mat]ial molecules con/itut+1 #ajc2 effectual only to unite p>ticles ( l nature1 #aaj2 induc+ *emical comb9ation1 #aab2 capill>y attraction1 an action (1 #aac4 ,co9s1 impressions tak5 f1 by contact1 #bbj2 by electricity1 #bba4 ,cold1 contraction caus$ by1 #bga1 #bgb2 mitigat$ by sl[ propagation ( heat 9 air1 #bgc2 g5]at$ by voltaic electricity1 #cjb2 increas+ ! conduct+ p[] ( ! air1 #cde4 ,colladon1 ,m41 exp]im5ts (1 te/+ ! velocity ( s\nd1 #ace4 ,collision betwe5 ! e>? & comets1 possibilities1 possible effects (1 #cfg1 #cfi4 ,collodion1 s5sitiv5ess (1 to light1 #bjc2 prop]ties (1 z an ag5t 9 photography1 #bjg4 ,col\rs1 sev5 prim>y1 #aei2 !ory ( ! decomposition ( :ite light into1 #afj2 degree ( refrangibility n inv>iable1 #afa2 ?ree prim>y1 ib42 new1 discov]$ by ,sir ,john ,h]s*el1 #afb2 rays refract$ )\t1 #afd2 r>ely homog5e\s1 #afe2 exp]im5ts on accid5tal & complem5t>y1 #afe1 #aff2 det]m9$ by undulations ( e!r1 exp]im5ts1 #agj-age2 ( mat]ial sub/ances1 :5ce d]iv$1 #age2 produc$ by analyz+ pol>iz$ light1 #ahf-ahh2 v>y+ ) refrangibility ( rays1 #aih2 obta9$ 9 photography1 #bjf2 images ( ! sol> spectrum imitat+ ! prismatic1 #bjh-bji2 ( seawe$s1 #bec2 n inv>iably dep5d5t on light1 ib42 affect$ by absorption & reflection1 #bfh2 ( ! electric sp>k1 affect$ by ! atmosph]e1 #bhi2 ( ! voltaic spectrum1 #cjc2 ( ! electric sp>k1 #cjd2 produc$ by oxidation on silv]1 #cje2 ( ! fix$ />s1 #dja1 #djb2 ( planet>y nebul1 #dab2 ( nebul\s clu/]s1 #dae4 ,columbus1 b$s ( alg f\nd by1 #bec4 ,column1 capill>y1 =ces produc+ *anges 9 its =m1 #aad1 #aae4 ,coma ,b]5ices1 a nebul\s clu/]1 #dae2 nebul\s zone pass+1 #daf1 #dag4 ,combu/ion1 cause (1 #bgj2 def9$1 #cjd4 ,comets1 attraction by ! sun (1 #e2 di/urbances 9 ! motion (1 a key to ! nature ( ! e!real m$ium1 #bb2 retrograde motion 91 #cc2 pass+ ?r\gh ,jupit]'s satellites1 #fi2 return (1 to _! p]ihelia1 furni%+ hi/orical data1 #hh2 exi/5ce ( ! lum9\s e!r demon/rat$ by1 #afh1 #afi2 t]re/rial atmosph]e unaffect$ by1 #ceh2 am\nt ( _! light comput$1 #ceh1 #cei2 passages (1 ?r\gh ! sol> sy/em1 #cei2 velocity1 pa?s (1 #cei1 #cfj2 pro( ( ! return (1 #cfj2 di/urb+ action ( planets on _! orbits1 #cfa2 ( #aggj1 an example1 #cfa1 #cfb2 comput$ return ( ,halley's1 #cfb1 #cfc2 aspects1 records ( ,halley's1 #cfc-cfe2 discov]ies made by ! revolutions (1 #cfe2 ( ! sol> sy/em1 ,encke's1 #cfe1 #cff2 ,biela's1 possibility ( collision )1 #cfg1 #cgj2 p]iods ( v>i\s1 #cgj2 cause ( _! brilliancy1 #cga2 velocity1 sun's influ5ce on1 #cga1 #cgb2 ( #ahdc1 #cgb1 #cgc2 _! con/itution1 #cgc1 #cgd2 ( #ahaa1 its lum9\s envelopes1 #cgd1 #cge2 sudd5 convulsions 91 #cge2 tails1 #cge-cgg2 causes assign$ = contraction ( diamet] 91 #cgg1 #cgh2 ,donati's1 #cgh1 #cgi2 nature ( _! light1 #cgi-cha2 computations ( _! numb]s1 #cha1 #chb2 orbits (1 #chc2 nebula resembl+1 #dac4 ,compass1 m>9]'s1 ph5om5a di/urb+1 #cab2 int5sity ( a galvanic curr5t measur$ by1 #cae4 ,compression ( ! t]re/rial sph]oid1 calculations (1 #dh-ea2 cause ( ! great1 9 ,jupit]1 #ff2 measures (1 f pressure ( sup]9cumb5t mass1 #gh2 effect (1 on magnetic action1 #cea4 ,concord1 a1 9 music1 #adb4 ,conductors ( electricity1 #bhd1 #bhe2 lightn+1 #bic2 molecul> /ructure det]m9+ ! p[] (1 #cjc4 ,conic sections1 conditions compell+ bodies 9 space to move 91 #e2 pr9ciple det]m9+ _! nature1 #aa4 ,con/ellations1 ne>e/ ! sun1 #cij2 :]e ! orbit ( ! sol> sy/em lies1 #djf2 occupi$ by ! nebul\s sy/em1 #dag4 ,contraction caus$ by cold1 #bga1 #bgb4 ,cook1 ,capta91 object ( 8 fir/ voyage1 #ec4 ,coop]1 ,mr41 li/ ( miss+ />s drawn up by1 #cie4 ,copp]1 electricity communicat$ to plates (1 #bbj2 lightn+-conductors (1 #bic2 action ( an electro-magnet on1 #cea1 #ceb4 ,cordi]1 temp]ature ( m9es obs]v$ by1 #bbh4 ,cordill]as1 effect on temp]ature ( _! table-l&s1 #bda4 ,corn1 a1 field us$ to illu/rate ! propagation ( s\nd1 #abi1 #acj4 ,cornwall1 hot-spr+s 9 m9es (1 #bbi4 ,corona ,au/ralis1 nebula 91 #dad4 ,corpuscul> !ory ( light1 #afg2 ph5om5a disprov+1 #aga1 #age1 #agf4 ,cosegu9a1 volcanic irruption (1 #bcc4 ,c\lomb1 in/rum5t measur+ electrical int5sity1 inv5t$ by1 #bhg4 ,creation1 va/ness & magnific5ce (1 #b4 ,crimea1 cause ( ! great /orm 9 !1 #abb4 ,cross1 ,mr41 voltaic batt]y ) con/ant action inv5t$ by1 #cjj4 ,cross1 ! ,s\!rn1 vacant pat*es ( ! ,milky ,way ne>1 #chf4 ,cry/allization def9$1 #ajf2 =ms (1 _! v>iety affect$ by temp]ature1 #ajg1 #ajh2 p]man5t & v>iable =ms1 #ajh1 #aji2 cleavages 91 #aji2 common to all sub/ances1 ib42 by ! ag5cy ( electricity1 #cjh1 #cji4 ,cry/als1 conditions det]m9+ _! =ms1 #ajg-aji2 optic axes (1 #ahc2 us$ 9 pol>iz+ light1 #ahf1 #ahh2 *anges 91 effect$ by compression1 #ahi2 transmission ( rays ( heat by1 #beh2 expansion (1 by heat1 #bgb1 #bgc2 =m$ by electricity1 #cjh2 action ( magnetism 91 #cdi1 #cej2 circum/ances det]m9+ ! set (1 #cej1 #cea2 effect ( temp]ature on magnetiz$1 #ceb4 ,cumm+1 ,pr(essor1 exp]im5ts (1 9 !rmo-electricity1 #ccc4 ,curr5ts1 two great1 sett+ f ea* pole t[>ds ! equator1 #ajj2 prov+ ! rotation ( w9ds1 #abd1 #abe4 ----1 electric1 fl[ (1 regulat$ by ,volta1 #big-bii2 *>act]i/ics ( ,voltaic1 #cja2 conductors1 non-conductors (1 #cji2 cont9u\s fl[ ( ,voltaic1 #cab2 action (1 on magnets1 #cac-cae2 reciprocal & mutual action ( magnetic & electric1 #caf1 #cag2 ,ampre's !ory (1 unsolv$ difficulties1 #cag1 #cah2 effect (1 on pol>iz$ rays1 #cai2 electric1 evolv$ by magnets1 #cbb1 #cbc2 _! p[] ( produc+ induction1 #cbd2 direction (1 produc$ by rotation1 #ccj-ccb2 evolv$ by application ( heat1 #ccb1 #ccc2 produc$ by int]sect+ magnetic curves1 #cci2 induc$ by cross+ t]re/rial l9es ( magnetic =ce1 #cdb4 ,curves1 describ$ by bodies project$ 9 space1 #e4 ----1 magnetic1 #cch2 electricity produc$ by int]sect+1 #cci2 nature (1 prov$ by ,dr4 ,f>aday1 #cci1 #cdj2 t]re/rial1 #cda1 #cdb2 ext5t ( ! range ( t]re/rial1 #cdd2 complete connect$ sy/em ( ! t]re/rial1 #cde2 inductive effect on ! ,atlantic telegraph1 #cdf2 diamagnetic1 #cdh4 ,cyanite1 *anges effect$ 91 by magnetism1 #cdi4 ,cyanotypes1 col\r$ photographs obta9$ by1 #bjf4 ,cygni #fa1 di/ance f ! sun (1 #chi2 orbit & mass (1 #cih1 #cii2 col\rs1 #dja2 mass1 #djd2 prop] motion1 #dje4 ,cygnus1 portion ( ! ,milky ,way ly+ betwe5 ,c5tauri &1 #chf4 ,cyl9d]s1 rotat+ by electricity1 #cac2 electro-dynamic1 #caf4 ,dalcoa? copp]-m9e1 its temp]ature1 #bbh4 ,dagu]re1 ,m41 8 inv5tions 9 photography1 #bje2 action ( light on ! iodide ( silv] expla9$ by1 #bai4 ,dagu]reotype1 !1 inv5tion (1 #bje4 ,dalton1 ,dr41 law ( def9ite proportion e/abli%$ by1 #aaa2 law ( ! w9d's rotation obs]v$ by1 #abe4 ,damoiseau1 ,m41 p]turbations ( a comet comput$ by1 #cfg4 ,daniell1 ,pr(essor1 ,voltaic batt]y improv$ by1 #bii4 ,daubuisson1 ,m41 obs]vations (1 9 m9es1 #bbh4 ,davy1 ,sir ,humphry1 8 fir/ attempts to produce photographic pictures1 #bjc-bjd2 exp]im5t (1 prov+ id5tity ( heat & motion1 #bge2 exp]im5ts on ! electric spectrum1 #bhi2 alkalies1 e>?s decompos$ by1 #cjg4 ,days1 law det]m9+ ! l5g? (1 #ga2 p]iod ( ! mean sid]eal & sol>1 #hc2 v>y+ ) ! seasons1 #hd2 decimal division (1 #hd2 sev51 ! mo/ p]man5t division ( "t1 #he4 ,deccan1 !1 :eat rip5+ 91 #bej4 ,decemb]1 #ahcb1 disappe>ance ( ,saturn's r+s 91 #fg2 co9cid5ce ( mean & app>5t "t 91 #hd2 date ( ,*ri/'s nativity1 #he2 ! a/ronomical ye> beg9n+ 91 #hf4 ,decimal division ( "t1 #hd4 ,decl9ations ( ! moon1 #ig4 ,decomposition1 effect$ by electricity1 #cjg-cjh2 by magnetism1 #cbc2 by !rmo-electricity1 #ccc4 ,delambre1 8 computations ( ! l5g? ( ! ye>1 #cei4 ,delta ,cephei1 a v>iable />1 #cia4 ,d5m>k1 c\rse ( ! tidal wave to1 #id4 ,d5sity1 v>iable1 imp$+ s\nd1 #ace1 #acf3 ( m$ia1 modify+ refraction1 #aec4 ,d5sities ( heav5ly bodies1 =mula f9d+1 #ef2 exp]im5ts1 #eg1 #eh2 comp>ative ( ! t]re/rial globe1 #gg1 #gh4 ,des]ts1 caus+ monsoons1 #abd2 influ5ce (1 on temp]ature1 #bdc4 ,dew1 cause ( its deposition1 #bfi4 ,diamagnetic sub/ances1 #cce1 #ccf4 ,diamagnetism def9$1 #cce2 sub/ances x is resid5t 91 #ccf2 discov]y1 *>act]i/ics (1 #cdg2 neutral sub/ances obta9$ by proportionate comb9ation (1 ) p>amagnetism1 ib42 pol>ity (1 #cdh2 connect$ ) arrangem5t ( molecules1 #cej-cea2 affect$ by division & compression1 #cea2 possibly id5tical ) p>amagnetism1 #cef1 #ceg4 ,diamet] ( ! e>?1 #ba2 ,jupit]'s pol>1 #bg2 excess ( 8 equatorial1 #ci2 app>5t1 ( ! sun & moon1 ne>ly equal1 #dj2 ( ! e>?1 #di2 ( bodies compos+ ! sol> sy/em1 #ef2 ( ,neptune1 #fc2 comets lack+ a s5sible1 #cgc2 contraction (1 9 comets1 #cgg2 causes assign$ =1 #cgg1 #cgh4 ---- ( an annul> nebula1 #daj2 s5sible1 ( a planet>y nebula1 #dab4 ,diamond1 !1 pol>iz$ light reflect$ f1 #aic4 ,dielectrics 9 electricity1 #bhf4 ,dieppe1 se5 f ,ha/+s1 #aeg4 ,diff]5tial telescope1 !1 exp]im5ts to be made by1 #bbg4 ,discord1 a1 9 music1 #adb4 ,diurnal tides ( ! atmosph]e1 _! duration1 #aba4 ---- v>iations 9 mean values ( ! magnetic elem5ts1 #cdc4 ,db]e9]1 ,m41 spontane\s combu/ion discov]$ by1 #aab4 ,doldrums1 region ( !1 #abc4 ,dollond1 ,mr41 a*romatic telescope p]fect$ by1 #afe4 ,donati1 ,signore1 discov]y ( 8 comet1 #cgh2 *anges 91 its irregul>ities1 #cgi4 ,doradus1 nebul\s pat*es on1 #dag4 ,dorpat1 occultation ( a /> obs]v$ f1 #cfd4 ,d\ble nebul1 #daa4 ,d\ble />s1 catalogues (1 #cie1 #cif2 =mul obta9+ ! relative position & motions1 #cif1 #cig2 eclipse 9 ,virg9is1 #cig2 orbit (1 det]m9$1 #cih2 eclipse 9 ,h]culis1 ib42 orbits & p]iodic times (1 #cih1 #cii2 anomalies 9 motions1 #djj2 optically d\ble1 #djj1 #dja2 col\rs (1 #dja2 rays compos+ ! light (1 #dja1 #djb2 passage ( light f1 furni%+ data to asc]ta9+ _! actual di/ance1 #djb1 #djc2 data = f9d+ _! masses1 #djc1 #djd2 calculations f\nd$ on ! quantity ( light emitt$ f1 #djd2 real & app>5t motions (1 #djd-djf2 app>5t p]iodic "t1 #djf1 #djg2 connection ( elliptical nebul )1 #daa4 ,dove1 ,pr(essor1 law ( ! w9d's rotation develop$ by1 #abe2 av]age temp]ature ( ! e>?'s surface e/imat$ by1 #bcg4 ,draco1 nebul\s sy/em 91 #dag4 ,drap]1 ,pr(essor1 exp]im5ts (1 on fluoresc5ce ( light1 #aih2 exp]im5ts 9 photography1 #bac2 prop]ties ( p>a!rmic rays discov]$ by1 #bai2 spectrum produc$ f diffract$ light1 #bbc2 !ory ( heat propagat$ by undulations1 #bfg4 ,dunlop1 ,mr41 revolution ( a d\ble /> calculat$ by1 #djj4 ,dusej\r1 ,m41 di/ances ( comets comput$ by1 #cei4 ,dynamic electricity1 #big4 ,see ,voltaic4 ---- !ory ( heat1 fundam5tal pr9ciple (1 #ceg4 ,dynamic equator ( ! e>?1 #cdc4 ,dynamical !ory ( heat1 #bgd1 #bge2 illu/rat$ by liquefaction & cond5sation1 #bgh2 by g5]ation ( /eam1 #bgf1 #bgg2 p[] ( nature1 #bgi-bha4 ,dynamics1 pr9ciple 91 a law1 ) reg>d to ! e>?'s rotation1 #gb2 electro1 discov]y ( action ( curr5ts 91 #caf2 ! !ory (1 univ]sal application (1 #dbf1 #dbg4 ,e>?1 !1 influ5ce ( its =m on attraction1 #d2 squ>e ( ! moon's di/ance f1 #e2 =m (1 #f1 #g2 moon's influ5ce on its rotations1 #g2 diamet] (1 #ba2 mean di/ance f ! sun1 ib4 note2 p]man5ce ( revolution 9 its times & seasons1 #bc2 p]turbation 9 ! mean motion ( ,v5us &1 #bf2 pro( ( ! motion (1 9 its orbit1 ( its rotation1 #cb2 v>iations 9 its attraction ( ! moon1 #cg2 compression ( its sph]oid1 #ch2 int]nal /ructure (1 #ci2 its mean di/ance f ! sun1 #dc2 !oretical inve/igation ( its figure1 #dd-df2 dim5sions (1 det]m9$1 #dh1 #di2 figure (1 f\nd by calculat+ its v>iations 9 gravitation1 #di-ea2 d5sity comp>$ ) ! sun1 #ef2 exp]im5ts f9d+ its mean d5sity1 #eg1 #eh2 rate ( revolution r\nd its axis1 #eh2 its diurnal rotation immutable1 #ga1 #gb2 *anges 9 temp]ature & _! causes1 #gc1 #gd2 nature ( ! revolutions produc+ geological *anges1 #gf1 #gg2 conjectures t\*+ its int]nal /ructure1 #gh2 effects produc$ by sol> & lun> attraction affect+ its equator1 #gi-ha2 its =m furni%+ /&>ds ( weight & measure1 #hi2 rotation (1 act+ on tides1 #ib2 attraction (1 affect+ ! lun> atmosph]e1 #bbf2 conjectur$ con/itution ( its int]ior1 #bca1 #bcb2 pr9ciples regulat+ ! diffusion ( sol> heat1 #bcg-bdg2 di/ribution ( kn[n species ( plants ov]1 #bdi-beb2 electric t5sion (1 #bia2 l9es ( magnetic =ce issu+ f1 #cda2 magnetic prop]ties (1 #cdb1 #cdc2 effect ( its collision ) a comet1 #cfh2 ne>e/ approa* ( comets to1 #cfi2 passage ( light f ,c5tauri to1 #chh2 !ories ( meteors fall+ on1 #dba-dbc4 ,e>?quakes 9 ,s\? ,am]ica1 #bcd4 ,e>?s1 decompos$ by voltaic electricity1 #cjg4 ,ea/]n coa/s1 cause ( _! cold] climates1 #bdd4 ,ebb1 see ,tides4 b\lem5s ( m\nta9s 9 ,switz]l&1 cause (1 #bga4 ,e*oes1 !ory ( _! orig91 #acg1 #ach4 ,eclipses1 lun>1 accel]at$ revolutions prov$ by obs]vations (1 #cf2 obs]vations (1 confirm+ results ( analysis1 #ch2 pr9ciple regulat+ _! return1 #ci2 refraction ( rays by ! t]re/rial atmosph]e1 #dj4 ----1 sol>1 #dj2 effects ( light 91 #da4 ----1 planet>y1 #db2 ! sol> atmosph]e visible 91 #bbd2 ( d\ble />s1 #cig1 #cih4 ,ecliptic1 !1 =m+ ! equ9oxes1 #i2 latitude reckon$ f ! plane (1 ib42 deviations ( planet>y orbits f1 #aj2 =ces affect+ _! position t[>ds1 #ae2 _! comp5sat$ & uncomp5sat$ v>iations to ! plane (1 #ah1 #ai2 secul> v>iation 9 ! plane (1 #bc2 orbits ( satellites1 ne>ly p]p5dicul> to1 #cc2 lun> motions t[>ds1 #ce2 incl9ation ( ! sun's plane ( rotation to1 #fe2 incl9ation ( ! plane ( ,saturn's r+s1 #fg2 incl9ation ( ! plane ( ! t]re/rial equator1 #gi2 t5d5cy ( its plane to co9cide ) ! equatorial1 ib42 retrograde motion ( ! equ9octial po9ts on1 #hj2 obliquity (1 affect+ ! duration ( "t1 #hd4 ,ed9burgh1 comp>atively equal mean annual temp]ature (1 #bdf4 ,egypt1 hi]oglyphic manuscript f1 int]pret$ by a/ronomy1 #hi4 ,egyptians1 ! civil ye> (1 #he4 ,ela/ic impact1 ! f\ndation ( dynamical !ories1 #ceg4 ,ela/icity1 prop]ty (1 resi/+ compression1 #aje4 ,electric telegraphs1 exp]im5t sugge/+ ! pr9ciple (1 #cbc2 con/ruction (1 #cbe-cbh4 ,electricity assum$ z ! m$ium attract+ p>ticles ( matt]1 #ajc1 #ajd2 id5tical ) *emical aff9ity1 #aaj2 9 composition & decomposition1 subject to laws ( def9ite proportion1 #aab2 influ5c+ w9ds1 #abe2 its comp>ative velocity1 #ach2 produc+ phosphoresc5ce1 #bag2 communicat$ to metal plates by juxtaposition1 #bbj2 impressions trac$ on glass by1 #bba2 rays excit+1 #bbc2 a dual p[]1 #bhb2 modes ( excit+ by di/urb+ equilibrium1 #bhb-bhd2 transmission (1 #bhd1 #bhe2 transmission by induction1 #bhe1 #bhf2 laws ( attraction & repulsion det]m9+ int5sity (1 #bhf-bhh2 heat & light produc$ by1 #bhh2 velocity (1 #bhi2 exp]im5t det]m9+ its velocity1 #bij2 developm5t (1 9 ! atmosph]e1 #bia1 #bib2 phosphoresc5ce excit$ by1 #bid2 ,voltaic1 see ,voltaic2 conduction ( /atic1 contra/$ ) ,voltaic1 #cji2 laws ( action 91 di/+ui%+ x f ,voltaic1 #cag2 relation betwe5 #cbb1 #cbc2 telegraphs work+ by1 #cbc-cbh2 produc$ by rotation1 #ccj1 #cca2 !rmo1 #ccb1 #ccc2 exact balance ( its dual =ce1 #ccd2 po9ts ( analogy betwe5 magnetism &1 #cdj1 #cda2 caus+ convulsions 9 comets1 #cge4 ,electro-dynamics1 see ,dynamics4 ---- magnetism1 see ,magnetism4 ,elem5ts1 ! ?ree t]re/rial magnetic1 #cdc2 v>iations 91 ib42 /orms affect+1 #cdd4 ,elevation1 effect (1 on temp]ature1 #bdj-bdb2 on vegetation1 #bej4 ,ellipses1 describ$ by planets1 #e2 pa?s ( planets describ+1 #aj2 prev5t+ comp5sation ( di/urbance1 #ae2 cause & measures ( v>iation 91 #ag2 describ$ by comets1 #cfc1 #cff4 ,ellipsoid1 an1 ( revolution1 mass assum+ ! =m (1 #de2 its equatorial & its pol> radius1 #dh2 p]man5t axes ( rotation1 #gf4 ,elliptic motion1 ratio ( =ces procur+1 #chb4 ,elliptical pol>ization ( light1 #aib1 #aic2 ( heat1 #bfg4 ---- nebul1 #dji2 _! connection ) d\ble />s1 #daa2 frequ5cy1 #dac2 difficult ( resolution1 #dae4 ,encke1 ,pr(essor1 sun's p>allax f\nd by1 #ec2 8 comet1 #afi2 aspects1 p]iod ( 8 comet1 #cfe1 #cff2 cause ( accel]ation 9 its revolution1 #cff1 #cfg2 cross+ ! t]re/rial orbit1 #cfh2 prospective & pres5t planet>y influ5ce on1 #cfi2 disappe>ance ( its tail & nucleus1 #cfi2 ref]r$ to1 #cgg2 contraction ( diamet]1 ib4 ,engl&1 arcs ( ! m]idian measur$ 91 #dh2 c\rse ( ! tidal wave t[>ds its we/ coa/1 #id2 peculi>ities ( photography 91 #bac2 meteors fall+ 91 #dba4 ,engrav+s copi$ by photography1 #bjd2 impressions tak5 by contact ) iodiz$ silv]1 #bba2 impressions tak5 f1 by galvanism1 #cji4 ,epipolic light1 #aig4 ,epsilon ,orionis1 zone ( />s pass+ ?r\gh1 #che4 ,equation ( ! c5tre1 def9$1 #i2 lun>1 #ce4 ,equator1 !1 =ces compell+ ! wid] circle (1 #f2 incl9ation ( ! t]re/rial to ! plane ( ! ecliptic1 #bc2 ( ! sol> sy/em1 #bd2 measure ( ! c5trifugal =ce at1 #di2 calculation f lun> action on ! t]re/rial1 #ee2 effects produc$ by ext]nal attraction influ5c+ ! direction ( its plane1 #gi1 #hj2 inequality 9 its pol> motion1 #ha2 cause ( ! calms at1 #abb2 dep? ( ! und]gr\nd /ratum ( con/ant temp]ature at1 #bbh2 maximum ( sol> heat+ influ5ce1 #bch2 sup]ficial ext5t ( l&1 #bdd2 mean annual temp]ature1 #bde4 ,equator ( ! sun1 maximum ( sol> heat atta9$ 91 #bbe4 ----1 dynamic1 surr\nd+ ! t]re/rial globe1 #cdc4 ----1 magnetic1 ( ! e>?1 #cdc4 ,equ9octial circle1 !1 def9$1 #i4 ---- po9ts1 effects ( sol> & lun> attraction on1 #gi2 p]iod ( _! revolution1 #hj2 measur+ "t1 #hc4 ,equ9oxes1 !1 def9$1 #i2 v5ial1 a po9t :5ce planet>y motions are e/imat$1 ib42 ( ! planets1 cause ( a precession 91 #ff2 causes prev5t+ _! inv>iable correspond5ce ) po9ts ( ! ecliptic1 #gi2 precession affect+ ! seasons1 #hj2 secul> motion (1 p]iodic v>iations1 #hj1 #ha2 eras dep5d+ on ! precession (1 #hf1 #hg2 tides augm5t$ 91 #ig4 ,eras1 a/ronomical1 det]m9$ by ! position ( ! major axis ( ! sol> ellipse1 #hf1 #hg4 ,erato/h5es1 ! e>?'s circumf]5ce measur$ by1 #di4 ,eridanus1 nebul\s pat*es cross+1 #dag4 ,erman1 ,m41 depression ( ! b>omet] obs]v$ by1 #abj4 ,eruptions1 volcanic1 record$1 #bcd4 ,eta ,aquil1 a v>iable />1 #cia4 ---- ,args1 zone /ret*+ f1 #cij2 nebula r\nd1 #dah1 #dai4 ---- ,coron1 p]iodic "t (1 #cih4 ,etna1 measurem5ts (1 #abj4 ,e!real m$ium1 undulations (1 propagat+ heat1 #bfg2 p]meable to l9es ( magnetic =ce1 #cdd2 its d5sity1 #cef2 transmitt+ gravity1 ib42 magnetic1 #cef1 #ceg2 (fices dis*>g$ by1 #ceg2 p]vad+ ! visible creation1 #ceh2 influ5ce (1 on comet motion1 #cfe2 a/ral revolutions accel]at$ by1 #cff2 probable increase 9 d5sity (1 #cfg4 ,europe1 atmosph]ic wave pass+ ov]1 #aba2 causes ( v>iation ( climate 91 #bdd2 sep>ation ( iso!rmal l9es 9 high latitudes (1 #bde2 diff]5ces ( latitude enjoy+ ! same mean temp]ature1 #bdf2 indig5\s productions (1 #bdi2 numb] ( indig5\s productions common to ,au/ralia &1 #bea2 numb] ( species ( =e/ trees1 #beb4 ,eudoxus1 ,plato's contempor>y1 a/ronomical obs]vation (1 #hh4 ,evaporation1 conditions affect+1 #bfi1 #bgj4 ,ev]e/1 ,colonel1 arc ( ! m]idian measur$ by1 #dh4 ,exc5tricity ( planet>y orbits measur$1 #ag4 ,expansion1 univ]sal law (1 #bga2 accuracy 9 measurem5t ensur$ by laws ( unequal1 #bgb2 ( cry/als1 #bgb1 #bgc2 !ory (1 #bge1 #bgg2 ( /eam1 #bgh2 by electricity1 #bhe4 ,extra-tropical w9ds1 #abd4 ,fabricius1 ! comet ( #aeef obs]v$ by1 #cgj2 v>iable />1 #cij4 ,fahr5heit1 mode ( asc]ta9+ heights propos$ by1 #abj4 ,fall+ />s1 #dbj2 !ories (1 #dbb1 #dbc4 ,f>aday1 ,dr41 gases r$uc$ to liquids by1 #aje2 exp]im5ts te/+ *emical aff9ity1 #aaa2 in/ance ( cohesive =ce induc+ *emical comb9ation1 #aab2 exp]im5ts on vibrations produc+ col\r1 #agc2 influ5ce ( dialectrics1 #bhf2 *emical orig9 ( electricity def5d$ by1 #cjj2 electro-*emical decomposition def9$ by1 #cjh2 rem>ks (1 on conduction ( voltaic electricity1 #cji2 exp]im5ts on magnetic rotation1 #cac2 exp]im5t magnetiz+ pol>iz$ light1 #cah1 #cai2 importance ( 8 exp]im5t1 #cbj2 exp]im5t e/abli%+ ! id5tity ( magnetism & electricity1 #cbb1 #cbc2 8 magnetic batt]y1 #cbd1 #cbe2 aid giv5 by1 9 con/ruction ( telegraphs1 #cbf1 #cbh2 electricity produc$ by rotatory motion expla9$1 #ccj2 8 classification ( sub/ances accord+ to magnetic qualities1 #ccb2 quotation f1 on cons]vation ( =ce 9 electricity1 #ccd2 magnetism rais$ to a new sci5ce by1 #cce2 ! magnet z repres5t$ by1 #cch2 exp]im5t det]m9+ ! =ms ( magnetic l9es ( =ce1 #cci1 #cdj2 accid5tal electro-magnetic comb9ations po9t$ out by1 #cdb2 8 discov]y ( diamagnetism1 #cdg2 exp]im5ts on magnetic action 9 cry/als1 #cdi2 obs]vations on influ5ce ( heat 9 magnetism1 #ceb2 def9ition ( gravity que/ion$ by1 #ced1 #cee2 magnetism ( ! e!real m$ium te/$1 #cef4 ,fauna1 di/9ct1 ( sep>ate regions1 #bed1 #bee4 ,faye1 ,m41 8 conception ( ! sun's con/itution1 #da2 8 !ory ( ph5om5a obs]v$ 9 eclipses1 #db2 comet ( #ahdc discov]$ by1 #cfa4 ,fi$l]1 ,dr41 fulgorites exhibit$ by1 #bic4 ,fire1 *emical comb9ation produc+1 #bgj4 ---- balls1 !ory (1 #dba4 ,fires1 c5tral1 subt]ranean1 #bca-bcg4 ,fi%1 phosphoresc5t1 #bid1 #bie2 electric1 #caj4 ,fix$ />s4 ,see ,/>s4 ,fizeau1 ,m41 decisive exp]im5t 9 pro( ( ! undulatory !ory ( light accompli%$ by1 #bjb4 ,flame1 *emical comb9ation evolv+1 #bgj1 #bga4 ,flames1 lamb5t1 caus$ by electricity1 #bid4 ---- div]g5t f ! nucleus ( a comet1 #cfd4 ,flet*]1 ,mr41 p]iodic "t ( ,virg9is det]m9$ by1 #cih4 ,flora ( ! ,himalaya1 #bej2 di/9ct1 9 sep>ate regions1 #bea2 condition e/abli%+ di/9ct1 9 isl&s1 #beb4 ,flor5ce1 comet discov]$ f1 #cgh4 ,fluor-sp>1 its prop]ty ( dim9i%+ refrangibility ( light1 #aif4 ,fluoresc5ce ( light1 def9ition (1 #aie2 vibrations ( ! sub/ance produc+1 #aif2 exp]im5ts1 #aig1 #aih4 ,focus ( a meteoric %[]1 #dbb4 ,fog1 yell[1 exclud+ ! *emical action ( rays1 #bad4 ,=bes1 ,pr(essor1 temp]ature ( ! boil+ po9t asc]ta9$ by1 #abj2 obs]vations (1 on rayless l9es1 #afc2 lun> heat te/$ by1 #bbg2 exp]im5ts (1 9 pol>ization ( heat1 #bfd1 #bfg4 ,=ce1 relation (1 to heat1 #bge2 trans=m+ solids to liquids & to vap\r1 #bge1 #bgg2 a p[] ( nature1 #bgi2 light & heat modes (1 #bai1 #bbj2 heat a liv+1 #cbi2 l9es ( magnetic1 #cch1 #cdj2 cons]vation (1 ma9ta9$ 9 p]iodic v>iation ( atmosph]ic magnetism1 #cde2 increatable1 inde/ructible1 #cec2 examples ( cons]vation (1 #ced2 fundam5tal pr9ciple ( cons]vation1 #ceg2 influ5ce & action ( ! gravitat+1 #dbd1 #dbf4 ,=ces1 ! unkn[n cause ( motion1 #e et passim2 c\nt]action ( sol> & tang5tial1 9 planet>y motion1 #h2 adju/m5t (1 ensur+ ! p]man5ce ( ! sol> sy/em1 #aa1 #ab2 ?ree p>tial1 caus+ p]turbation 9 planet>y motion1 #ad1 #ae2 excess ( equatorial diamet] ! orig9 (1 #bg1 #bh2 ?ree1 di/urb+ lun> motions1 #cd1 #ce2 det]m9+ planet =ms1 #dd1 #de2 produc+ tides1 #ia1 #ib2 comb9+ to =m ! c5trifugal1 #ajj2 act+ on molecules ( matt]1 #ajb1 #aje2 produc+ capill>y ph5om5a1 #aad2 lat5t1 9 nature1 #bgi1 #bhj2 "o univ]sal p[]1 ! root ( all1 #cba2 exact balance (1 9 electricity1 #ccd2 k9dr$ & conv]tible1 #cec2 develop+ comets' tails1 #cge2 det]m9+ ! =ms ( orbits1 #chb1 #chc2 ma9ta9+ ! /ability ( ! sol> sy/em1 #dbf2 mutual relations (1 #dbg4 ,=e/s1 *ange produc$ 9 ! atmosph]e by1 #bda1 #bdc2 numb] ( species ( trees f\nd 9 ,am]ican & ,european1 #beb4 ,=m5t]a1 quadrant ( ! m]idian pass+ ?r\gh1 furni%+ a unit ( l9e> measure1 #hi4 ,=nix1 nebul\s pat*es cross+1 #dag4 ,=/]1 ,lieut5ant1 conv]sation c>ri$ on by1 across ,port ,b[5 ,h>b\r1 #acf4 ,fossil plants1 an evid5ce ( *ange 9 temp]ature1 #gd4 ,f\ri]1 mean temp]ature ( space accord+ to1 #aai2 rate ( decrease 9 ! e>?'s c5tral heat comput$ by1 #bcb4 ,fox1 ,mr41 temp]atures 9 m9es te/$ by1 #bbh1 #bbi2 law ( p>amagnetic =ce asc]ta9$ by1 #cch2 obs]vations 9 m9es1 prov+ ag5cy ( electro-magnetism1 #cdf4 ,france1 arcs ( ! m]idian measur$ 91 #dh2 unit ( l9e> measure 91 #hi2 mode ( ari?metical computation1 #ij2 atmosph]ic pressure 91 #abj2 cliffs (1 se5 f ,ha/+s1 #aeg4 ,fraunh(]1 ,m41 discov]y ( rayless l9es 9 ! sol> spectrum1 #afb2 comp>ative refrangibility ( rays asc]ta9$ by1 #afc2 data furni%$ by1 to det]m9e ! disp]sive p[] ( rays1 #afe2 8 discov]y det]m9+ ! l5g? ( waves indep5d5tly ( refraction1 #bja2 spectrum ( an electric sp>k obs]v$ by1 #bhi4 ,freez+1 temp]ature requir$ =1 "u pressure1 #bga2 !ory (1 #bgf4 ,fresnel1 ,m41 8 te/imony 9 fav\r ( ! undulatory !ory ( light1 #aga2 !ory ( refraction1 #ahc2 discov]ies 9 pol>ization ( light1 #aia1 #aic4 ,freyb]g1 gre5 plants f\nd 9 m9es at1 #bec4 ,friction evolv+ heat1 #bgd1 #bge2 electricity1 #bhb1 #bhc4 ,fr+es ( col\r$ light bord]+ %ad[s1 #agd1 #age2 produc$ by int]f]5ce ( pol>iz$ rays1 #aid4 ,fulgorites1 f\nd 9 ,silesia1 #bic4 ,fundy1 ! ,gulf (1 cross tides p\r+ into1 #id4 ,gage1 ,mr41 exp]im5ts (1 on magnetism1 #cae4 ,gales4 ,see ,w9ds4 ,galileo1 laws affect+ music discov]$ by1 #ade2 8 me?od ( f9d+ di/ances ( fix$ />s1 #chh4 ,galle1 ,dr41 ,neptune's place communicat$ to1 by ,le ,v]ri]1 #fb4 ,gall[ay1 ,mr41 sun's motion prov$ by1 #dje4 ,galvani1 ,pr(essor1 peculi> effects ( electricity sugge/$ to1 #big4 ,galvanism1 ph5om5on sugge/+ ! !ory (1 #big2 batt]ies1 #bih1 #cjj2 heat & light evolv$ by curr5ts (1 #cjj1 #cjd2 decomposition & composition1 #cjg1 #cjh2 appli$ to plat+ & gild+1 #cji2 effect ( heat on1 #caj2 effect (1 on ! s5ses1 ib42 fi% exhibit+ analog\s ph5om5a1 #caj1 #caa2 ph5om5a exhibit$ by curr5ts (1 on magnets1 #cab1 #cad3 int5sity ( a curr5t measur$1 #cae2 conditions obta9+ a circuit 91 #ccb4 ,galvanomet]1 ! pr9ciple ( its con/ruction1 #cae2 exp]im5t by means (1 id5tify+ magnetism & electricity1 #cbb1 #cbc4 ,gamb>t1 ,m41 p>abolic elem5ts ( a comet comput$ by1 #cfg4 ,gamma ,&rom$a1 col\rs (1 #dja4 ---- ,aqu>ii1 planet>y nebula ne>1 #dab4 ---- ,hydr1 a v>iable />1 #cia4 ---- ,leonis1 focus ( a meteoric %[] 91 #dbb4 ---- ,sagitt>ii1 clu/] ( ! ,milky ,way r\nd1 #chg4 ---- ,virg9is1 eclipse 91 #cig2 orbit ( ! revolv+ /> det]m9$1 #cih4 ,ganges1 !1 tidal wave at ! m\?s (1 #id4 ,g>dn]1 ,mr41 ext5t ( diametrically opposite l&s e/imat$ by1 #bdd4 ,gases1 conditions reta9+ matt] 9 ! =m (1 #ajd1 #aje2 comb9ations (1 #aaa2 transmission ( radiant heat ?r\gh1 #beh2 expansion (1 #bga2 voltaic spectrum modifi$ by1 #cjc2 effect ( heat on ! conduct+ p[]s (1 #cji4 ,gassiot1 ,mr41 exp]im5ts (1 on ! electric dis*>ge1 #cjf2 connexion betwe5 magnetism & light discov]$ by1 #cba2 electric app>atus improv$1 #cbh4 ,g5eva1 ! ,lake (1 exp]im5t on ! velocity ( s\nd 91 #ace4 ,g5sanne1 ,m41 increas+ temp]ature ( m9es te/$ by1 #bbh4 ,geograph]s1 lun> motions important to1 #db4 ,geological *anges1 probable cause (1 #gg4 ,geology1 ! lessons (1 #cbf4 ,georgia ,isl&1 ,s41 excess ( cold 91 ov] correspond+ latitudes1 #bda4 ,g]many1 %oot+ />s se5 f1 #dba4 ,gibralt>1 ! ,/raits (1 turn+ aside ! tidal wave1 #ih4 ,giromagny1 temp]ature ( ! lead-m9es (1 #bbh4 ,glass1 effect ( cohesion on plates (1 #ajf2 musical notes elicit$ f rods & plates (1 #add-adg2 transmission ( waves ( light 91 #agg2 pol>iz+ light1 #ahd1 #ahe2 elliptical pol>ization produc$ by1 #aic1 #aid2 us$ 9 photography1 #bjg2 impressions on1 f bodies 9 contact )1 #bbj2 impressions on1 trac$ by electricity1 #bba2 transmission ( radiant heat by1 #bei2 by col\r$1 #bfa1 #bfb2 its temp] alt]$ by magnetism1 #ceb1 #cec4 ,globul> clu/]s ( nebul1 #dac-dae4 ,gl[-dis*>ge obs]v$ by ,capta9 ,bonnyca/le1 #bie1 #bif4 ,gold1 action (1 on light1 #agc4 ,good ,hope1 ! ,cape (1 iceb]gs drift$ to1 #aja4 ,goodricke1 ,mr41 v>iable />s discov]$ by1 #cia2 opaque bodies repres5t$ z revolv+ r\nd fix$ />s by1 #cid4 ,graham1 ,mrs41 acc\nt ( an e>?quake by1 #bcd4 ,graham's comp5sation p5dulum1 #bgb4 ,gravitat+ =ce ( ! sun1 #cfe1 #dbd1 #dbe4 ,gravitation1 (fices (1 9 ! mat]ial creation1 #a1 #b2 process ( reason+ 9 asc]ta9+ ! law (1 #c2 law det]m9+ its int5sity 9 ! sol> sy/em1 #e2 complex action (1 by attraction 9 mass & 9 p>ticles1 #f2 increase (1 t[>ds ! poles ( ! e>?1 #de2 calculations f\nd$ on its increase1 #di-ea2 9 a m9e1 its excess ov] surface1 #eg2 action (1 modify+ tides1 #ib1 #ic2 law1 univ]sally act+ on matt]1 #aje2 ! air subject to1 #aag2 influ5ce (1 9 motions ( ! heav5ly bodies1 #chb1 #chc2 d\ble />s revolv+ by1 #cih2 /ell> sy/ems subject to1 #djj2 influ5ce (1 on nebul1 #daf2 a g5]al law ( ! visible creation1 #dbd2 mode ( its action1 #dbe1 #dbf4 ,gravity1 c5tre (1 9 sph]es1 effect ( impulses pass+ ?r\gh1 #g2 ( ! sol> sy/em1 inv>iable plane pass+ ?r\gh1 #bc2 /raight l9e describ$ by1 #bd2 action (1 9 det]m9+ ! figure ( ! e>?1 #dd1 #de2 def9ition irreconcilable ) ! cons]vation ( =ce1 #ced1 #cee2 "q ( its transmission1 #cee1 #cef4 ,great ,be>1 ! nebul\s zone pass+1 #daf4 ---- ,gobi1 !1 effect ( ! expansion ( air ov]1 #abd4 ,greeks1 a/ronomical obs]vations (1 confirm+ results ( analysis1 #ch4 ,gre5l&1 ocean on ! nor!rn coa/ (1 #id4 ,gre5wi*1 lun> di/ances comput$ =1 #dc2 quadrant ( ! m]idian pass+ ?r\gh1 furni%+ a unit ( l9e> measure1 #hi2 p]iodic circuits ( w9ds1 #abe4 ,grimaldi1 col\r$ fr+es bord]+ %ad[s describ$ by1 #age4 ,groombridge1 velocity ( 8 prop] motion1 #djd4 ,grot?us1 ! transmission ( voltaic electricity inve/igat$ by1 #bih4 ,grove1 ,mr41 copp] & z9c plates electrifi$ by1 #bbj2 sub/ances radiat+ heat ( diff]5t refrangibilities enum]at$ by1 #beg2 ! transmission ( voltaic electricity inve/igat$ by1 #bih2 electric heat te/$ by1 #cja1 #cjb2 rem>ks (1 on c>bon1 #cjb1 #cjc2 on ! voltaic arc1 #cjd1 #cje2 rem>ks (1 on light & heat1 #cai2 electric app>atus improv$ by1 #cbh2 8 def9ition ( ! e!real m$ium1 #cee4 ,grylli1 suppos$ delicate s5se ( he>+ 91 #acb4 ,guanaxato1 temp]ature ( ! silv]-m9e (1 #bbh4 ,gulfs sep>at+ />s1 #cij4 ,gum-guaiacum1 *emically affect$ by rays ( ! sol> spectrum1 #bjc2 condition ( its s5sibility to light1 #bjf2 effect ( r$ rays on1 #bji2 us$ 9 exp]im5ts on p>a!rmic rays1 #bag1 #bah4 ,gum-lac1 electrical int5sity measur$ by means (1 #bhf1 #bhg4 ,gymnotus electricus1 !1 #caj4 ,haid+]1 ,m41 exp]im5ts (1 prov+ wat] an ess5tial "p ( cry/als1 #ajg4 ,hail1 =mation (1 #bgj4 ,hales1 8 calculation ( ! am\nt ( surface expos$ by ! leaves ( a helian?us1 #bdc4 ,hall1 ,mr41 a*romatic telescope con/ruct$ by1 #afe4 ,halley1 elem5ts ( a comet's orbit comput$ by1 #cfb2 return ( 8 comet1 #cfc2 *anges 9 its aspect1 #cfc1 #cfd2 records (1 #cfe2 no solid nucleus 91 #cgd2 cause ( its lum9\s sectors1 #cgf2 ,sir ,john ,h]s*el's obs]vations on1 #cgh4 ,h>e1 !1 comet obs]v$ ne>1 #cgb1 #cgc4 ,h>monics ( ! fundam5tal note 9 music1 #adj1 #ada4 ,h>mony1 prop]ty ( s\nd regulat+1 #aca2 def9ition (1 vibrations produc+1 #adb4 ,h>ris1 ,sir ,william ,sn[1 exp]im5ts (1 9 electricity1 #bhg1 #bhh2 lightn+-conductors inv5t$ by1 #bic4 ,h>rison1 p5dulum inv5t$ by1 #bgb4 ,ha/+s1 coa/ ( ,france di/9ctly se5 f1 #aeg4 ,heat affect+ ! =m ( cry/als1 #ajg2 evolv$ 9 *emical comb9ations1 #aaj2 irregul> decrease (1 9 ! atmosph]e1 #aai2 maxima (1 9 ! sol> spectrum1 #bae2 peculi> *emical quality (1 9 p>a!rmic rays1 #bah2 impressions trac$ by1 #bbj-bbb2 p]iodical v>iations 9 ! sun's1 #bbe2 diff]5t proportions ( sol>1 rea*+ ! planets1 #bbe1 #bbf2 effect ( ! t]re/rial atmosph]e on lun>1 #bbg2 mode ( its developm5t 9 opaque bodies1 ib42 s\rces ( t]re/rial1 #bbh-bch2 irregul> di/ribution (1 #bci-bdg2 laws affect+ its radiation1 #beg2 its transmission1 #beh-bfb2 pol>ization (1 #bfd-bfg2 undulatory !ory1 #bfg2 absorption & reflection ( radiant1 #bfh2 ph5om5a caus$ by radiation (1 #bfi2 accumulation (1 produc+ light1 #bgj2 expansive =ce (1 #bga1 #bgb2 modes ( propagation1 #bgc1 #bgd2 produc$ by motion & equival5t to x1 #bgd-bgg2 laws regulat+ ! =ce ( artificial1 #bgi1 #bhj2 p[] evolv$ by application (1 #bhj2 id5tical 9 nature ) s\nd1 #bha2 electrical1 #bhh2 %eet-lightn+ caus$ by1 #bid2 phosphoresc5ce1 #bid2 develop$ by voltaic electricity1 #cja1 #cjb2 effect (1 on electrical conductors1 #cji2 connexion betwe5 ! production ( electricity &1 #caj2 its direct relation to magnetism & electricity1 #cai1 #cbj2 me*anical p[] & conv]tible =ces1 #cbi2 t]re/rial magnetism attribut$ to ! action (1 #ccc2 measur$ by electric curr5ts1 #ccd2 affect+ atmosph]ic magnetism1 #cdd2 fundam5tal pr9ciple ( ! dynamic !ory1 #ceg4 ,hel5a1 ,/41 di/9ct flora (1 #beb4 ,helix1 circul> & elliptical1 describ$ 9 pol>ization ( light1 #aib1 #aic2 electrical exp]im5ts by means (1 #cad2 induction (1 increas+ electric p[]1 #cbb1 #cbc4 ,hell]1 8 obs]vations on ! comet ( #aeef1 #cgj1 #cga4 ,helmholtz1 ,pr(essor1 p[] ( *emical =ce e/imat$ by1 #aab2 8 calculation ( ! *emical =ce develop$ by combu/ion1 #bgh2 ( ! am\nt ( lat5t =ce 9 our sy/em1 #bhj4 ,hemisph]e1 cause ( excess ( cold 9 ! s\!rn1 #bda2 sup]ficial ext5t ( l& 9 nor!rn & s\!rn1 #bdd4 ,h5ley1 ,mr41 magneto-electric ma*9e con/ruct$ by1 #cbe4 ,h5d]son1 ,pr(essor1 p>allax ( ,c5tauri calculat$ by1 #chg2 ( ,sirius1 #chi4 ,h5ry1 ,pr(essor1 exp]im5ts (1 on magnetism1 #cae4 ,h]apa?1 ,mr41 8 view ( ela/ic =ce pref]r$ to ,sir ,humphry ,davy's1 #bgf4 ,h]cules1 eclipse ( a d\ble /> 91 #cih2 globul> nebul\s clu/]1 #dad4 ,h]s*el1 ,sir ,william1 obs]vations ( ,saturn's & ,uranus's satellites by1 #cb1 #cc2 !ory (1 reg>d+ ! sol> con/itution1 #da2 cause ( effects ( light 9 eclipses accord+ to1 #db2 rotation ( ,jupit]'s satellites det]m9$ by1 #gj2 mutual indep5d5ce ( light & heat1 #bad1 #bae2 influ5ce ( ! sun's spots on heat1 #bbe2 po9t ( maximum heat 9 ! sol> spectrum1 #bfc2 comet ( #ahaa obs]v$ by1 #cgd2 its lum9\s envelopes exam9$1 #cge2 ! ,milky ,way exam9$ by1 #che2 8 discov]y ( ! orbital motions ( d\ble />s1 #chh2 catalogue ( d\ble />s by1 #cie1 #cif2 p]iodic "t ( ,virg9is det]m9$ by1 #cih2 eclipse ( a d\ble /> obs]v$1 ib42 b9>y sy/em discov]$1 #djj2 rem>ks on ! motions ( ! />s1 #dje2 nebul resolvable into />s1 #ejg4 ,h]s*el1 ,sir ,john1 approximate p]iods ( satellites asc]ta9$ by1 #cc2 ?ickness ( ,saturn's r+ comput$1 #fg2 obs]vations (1 on seasons1 #gd2 difficulty ( v>y+ "t1 9 obs]vations at di/ances1 obviat$ by1 #hf2 t5uity ( atmosph]ic air demon/rat$1 #aaj2 rapid decrease ( d5sity 9 ! atmosph]e1 #aah2 mean temp]ature ( space comput$ by1 #aai2 height ( ,etna measur$1 #abj2 8 explanation ( anomalies 9 atmosph]ic ph5om5a1 ib42 quotation f1 on ! transmission ( s\nd1 #acf2 obs]vations (1 on ?und]1 #ach2 rem>ks on ! absorption ( light by col\r$ m$ia1 #age1 #agf2 on pol>ization ( light1 #agi2 exp]im5talis+ app>atus1 #ahh2 discov]y ( epipolic light1 #aig2 discov]ies 9 photography1 #bje1 #bjf2 analysis ( ! sol> spectrum1 discov]y ( its *emical prop]ties1 #bjg-bai2 8 !ory ( volcanic action1 #bce-bcg2 obs]vations %[+ ! maximum ( heat+ influ5ce ( ! sol> rays1 #bch2 !ory ( ! orig9al di/ribution ( plants1 #bed2 div]g5t flame ( a comet obs]v$ by1 #cfd2 rem>ks on ! possible de/ruction ( ! sol> sy/em1 #cgb2 causes assign$ by1 = contraction ( diamet] 9 comets1 #cgh2 comp>ative lu/re ( />s measur$ by1 #chd1 #che2 ! ,milky ,way describ$1 #che1 #chf2 numb] ( />s 9 a gr\p ( ! ,milky ,way comput$1 #chg2 v>iable /> discov]$1 #cia2 rem>ks (1 on ! nature ( ! fix$ />s1 #cib2 v>iable />s discov]$ by1 #cic2 rem>ks on v>iable />s1 #cid2 /> miss$ by1 #cie2 d\ble />s discov]$1 #cif2 eclipse ( a d\ble /> obs]v$1 #cig2 orbits det]m9$1 #cih1 #cii2 obs]vations on col\rs ( d\ble />s1 #dja2 light ( ,c5tauri comp>$ ) ! moon's by1 #djd2 light ( ! fix$ />s calculat$1 ib42 obs]vations on nebul correct$1 #djg2 catalogues ( nebul1 #djh2 nebul discov]$ by1 #dji2 annul> nebula describ$1 #daj2 magnitude ( planet>y nebul comput$1 #dab2 globul> nebul\s clu/] describ$1 #dac2 law ( gravitation ascrib$ to nebul1 #daf2 nebula r\nd ,argus describ$1 #dah2 8 "w on ,nebul1 #dai4 ,h]s*el1 ,miss1 ,encke's comet se5 by1 #cfe2 catalogue ( nebul1 #djg4 ,hevelius1 div]g5t flames ( a comet describ$ by1 #cfd2 contraction 9 diamet] ( comets obs]v$1 #cgg2 phases 9 comets obs]v$1 #chj4 ,hi]oglyphics int]pret$ by a/ronomy1 #hi4 ,himalaya1 !1 inappreciable effect (1 on ! globe's surface1 #f2 s+ul> effect ( refraction on1 #aef2 cause ( great] elevation ( ! sn[-l9e on ! nor!rn side (1 #bda2 flora (1 #bej4 ,h9d1 ,mr41 comet's orbit comput$ by1 #cgj1 #cga2 obs]vations (1 on ,donati's comet1 #cgi2 v>iable />s discov]$ by1 #cia2 vani%+ /> discov]$1 #cic2 8 belief 9 planet>y sy/ems1 #cid4 ,h9do/an1 ! tidal wave /rik+ on its coa/s1 #id4 ,hipp>*us1 precession discov]$ by1 *ange ( seasons s9ce 8 age1 #hj2 ph5om5on sugge/+ 8 catalogue ( ! />s1 #cib4 ,hi/ory corroborat$ & correct$ by a/ronomy1 #hg1 #hi4 ,ho>-fro/1 cause (1 #bfi4 ,holtzmann1 ,m41 op9ion (1 ) reg>d to ! vibrations ( pol>iz$ light1 #bbc4 ,hoogly1 !1 bore (1 #id4 ,horizon1 effects produc$ by ! d5s] /ratum ( air 91 #aeg1 #aeh4 ,horologium1 nebul\s pat*es 91 #dag4 ,horton coal-m9e1 exp]im5ts ) ! p5dulum 91 #eg4 ,h\rs1 cause ( _! mal-correspond5ce ov] ! globe1 #hf4 ,hudson's ,bay1 tide 91 #ih4 ,humboldt1 8 suff]+s f r>ity ( ! atmosph]e1 #aah2 8 explanation ( ! app>5t great] acut5ess ( he>+ obs]v$ at night1 #ace2 obs]vations (1 9 m9es1 #bbh2 causes ( di/urbance 9 ! equal diffusion ( heat enum]at$ by1 #bdj2 id5tical productions ( ! ,old & ,new ,_w f\nd by1 #bea2 8 di/ribution ( palms & grasses1 #beb2 gre5 plants f\nd gr[+ 9 m9es by1 #bec4 ,hunt1 ,mr41 col\r$ image ( ! sol> spectrum obta9$ by1 #bji2 image obta9$ 9 ,engl&1 #bac2 8 exp]im5ts 9 trac+ images by juxtaposition ( bodies1 #bbj1 #bba2 exp]im5ts on ! cond5s+ p[] ( rays1 #bbc4 ,hurricanes1 orig9 & cause (1 #abe1 #abf2 curve describ$ by ! axis (1 ib42 _! ext5t & velocity1 #abf1abg2 ph5om5a result+ f _! revolv+ motion1 #abg2 laws (1 mak+ avoidance possible1 #abh4 ,huyg5s1 !ory orig9at$ by1 #afi4 ,hydrog51 proportion (1 9 wat] & gases1 #aaa2 spectrum f1 #cjc2 sep>at$ f wat] by electricity1 #cjg4 ,hygromet]1 dew-po9t measur$ by1 #bfi4 ,hyp]bolic motion1 ratio ( =ces procur+1 #chb4 ,iapetus1 se5 by ,mr4 ,lassell1 #cc4 ,ibn ,junis1 progress ( sci5ce 9 8 "t1 #ij4 ,ice1 =mation (1 #bga2 =ce act+ 9 its =mation1 #bgf2 /opp+ ! curr5t ( voltaic electricity1 #cji4 ,iceb]gs1 drift+ (1 #ajj1 #aja2 f>!/ range ( nor!rn & s\!rn1 #bda2 effect ( electricity 9 collisions1 #bhd4 ,icel& sp>1 its prop]ty ( d\ble refraction1 #aha2 pol>iz$ ray analyz$ by1 #ahg2 transmission ( radiant heat by1 #beh2 electricity elicit$ f1 #bhd4 ,illum9ation1 comp>ative1 ( objects1 exp]im5ts det]m9+1 #bbg4 ,images1 col\r$1 ( ! sol> spectrum1 #bjh-baa2 trac$ by contact & juxtaposition ( bodies1 #bai1 #bbj2 by electricity1 #bba2 by m$ia absorb+ hot rays1 #bbb4 ,india1 arcs ( ! m]idian measur$ 91 #dh2 discov]y ( ,saturn's r+1 #ff2 anci5t monum5t ( a/ronomical k1 #he2 obs]vations confirm+ ! antiquity ( a/ronomical sci5ce 91 #hh4 ,indian ,ocean1 ! tidal wave 91 #id2 monsoons bl[+ ov]1 #abd4 ,induction1 law (1 9 electricity1 #bhe1 #bhf2 magnetic1 #cad1 #cae2 ph5om5a (1 produc$ by electric curr5ts1 #cbd2 illu/rat$ by ! ,atlantic telegraph1 #cbe1 #cbf2 velocity ( electricity modifi$ by p[] (1 #cbg2 possibility ( electro1 furni%+ a motive p[]1 #cbh2 ( electricity by rotation ( magnets1 #ccj-ccb2 z possess$ by magnets1 #ccf2 p>amagnetism evolv$ by1 #ccg2 means ( accel]at+1 ib42 subject to ! laws ( me*anics1 #cch2 analogy betwe5 electric & magnetic1 #cda2 ( heav5ly bodies1 affect+ t]re/rial magnetism1 #cdf1 #cdg2 diamagnetic sub/ances capable (1 #cdh4 ,indus1 comet pass+ ?r\gh ! con/ellation (1 #cgi4 ,inequality1 !1 ( ,jupit] & ,saturn m>k+ hi/orical epo*s1 #hh4 ,insects1 law ( _! disp]sion1 #bee4 ,in/rum5ts1 musical1 #adc1 #adi1 #aej2 imitat+ articulation ( lett]s1 #aea1 #aeb4 ,insulation 9 electricity1 #bhe4 ,int]f]5ce1 laws (1 neutraliz+ undulations1 #ach1 #aci2 ! !ory (1 ref]r$ to a g5]al law1 #afi4 ,iota ,cet1 comet obs]v$ ne>1 #cgb4 ---- ,orionis1 a nebul\s />1 #daa4 ,irel&1 progress ( ! tidal wave t[>ds1 #id4 ,iron1 di/ill$1 #cje2 rotation ( its p>ticles1 ib42 magnetiz$ by electricity1 #cad1 #cae2 magnetic prop]ties (1 #ccb2 r5d]$ p>amagnetic1 #ccf1 #ccg2 magnetic & electric prop]ties (1 #cdg2 ela/icity (1 affect$ by magnetism1 #ceb4 ,isl&s1 "* ( _! floras1 #beb4 ,isogeo!rmal l9es ( temp]ature def9$1 #bch1 #bci2 p>allel ) ! iso!rmal l9es1 #bdf4 ,isomorph\s cry/als1 #aji4 ,iso!rmal l9es ( temp]ature def9$1 #bdj2 latitudes (1 deviation f ! l9e ( ! equator1 #bde2 =mula det]m9+1 #bdf2 simil>ity ( vegetation 9 ! same1 #bec4 ,italy1 local attraction1 occasion+ inaccuracy 9 measurem5t1 #dh4 ,ivory1 ,m41 8 me?od ( comput+ heights1 #abj2 8 !oretical inve/igation ( planet =ms1 #dd2 d$uction f measurem5t ( arcs ( ! m]idian1 #dh4 ,jacob1 ,mr41 discov]y ( ,saturn's r+ by1 #ff2 p]iodic "t ( ,c5tauri det]m9$ by1 #cii2 p]iodic "t ( #gj ,ophiu*i1 #djj4 ,james1 ,colonel1 measurem5ts (1 9 ! ,g5]al ,survey ( ,great ,brita91 #dg2 d5sity ( ! e>? det]m9$ by1 #eh4 ,jam91 ,m41 rem>ks (1 on sub/ances produc+ elliptical pol>ization1 #aic4 ,janu>y1 epo* ( its beg9n+ ! ye>1 #he4 ,jews1 d5om9ations ( "t 9 _! cal5d>s1 #he4 ,joseph/adt1 discov]y ( a comet f1 #cfg4 ,j\le1 ,mr41 heat consid]$ a me*anical =ce by1 #bge2 8 view ( ela/ic =ce1 #bgf2 am\nt ( lat5t =ce 9 a p\nd ( coal1 comput$ by1 #bgh2 furni%+ data to ,pr(essor ,?omson1 #bgi2 quantity ( heat g5]at$ 9 a unit ( "t by electricity comput$ by1 #cjb2 p[]ful magnet obta9$ by electricity1 #cae2 electric ma*9es con/ruct$ by1 #cbh2 exp]im5ts prov+ heat & me*anical p[] conv]tible1 #cbi4 ,jovial sy/em1 mass ( ! :ole1 #ee4 ,julian ,cal5d>1 ye> (1 ! fir/ ( our era1 #hf4 ,june1 #ahcc1 reappe>ance ( ,saturn's r+s1 #fg2 co9cid5ce ( times 91 #hd4 ,juno1 ! diamet] (1 #ef2 a/ronomical tables (1 #fc4 ,jupit]1 rotation (1 di/+ui%$ f ! o!r planets1 #g2 p]iodical inequality 9 8 motions1 #ae2 discov]y ( telescopic planets betwe5 ,m>s &1 #bj1 #ba2 diamet] (1 #ba2 8 position ) respect to ! equator ( ! sol> sy/em1 #bd2 inequalities 9 ! motion (1 app>5tly anomal\s1 #be1 #bf2 8 mass prov$ n homog5e\s1 #bi2 eclipses1 #cj1 #ca2 compression ( 8 sph]oid comput$1 #ci2 eclips$ by ,m>s1 #db2 mass (1 comp>$ ) ! sun1 #ee2 8 diamet]1 #ef2 increase ( d5sity 91 #eh2 a/ronomical tables (1 #fj2 rapid rotation1 #ff2 p]iod ( a ye> 91 ib42 effect ( 8 di/urb+ en]gy1 #ha2 photographic images (1 #bbf2 light reflect$ by 8 atmosph]e1 #bbg2 action (1 on ! comet ( #aggj1 #cfa1 #cfb2 on ,halley's comet1 #cfb1 #cfc2 comet revolv+ betwe5 ! orbits ( ! e>? &1 #cfg2 future influ5ce (1 on comets1 #cfi2 comet ne>ly approa*+ 8 f\r? satellite1 #cgj2 comets hav+ _! p]ihelia 9 8 orbit1 #cha4 ----1 orbit (1 revolutions ( its major axis1 s\rce ( v>iation 9 exc5tricity1 #ag2 sl[ revolution ( its nodes1 decrease 9 its incl9ation to ! ecliptic1 #ai4 ---- ) 8 satellites1 an epitome ( ! sol> sy/em1 #bg2 effect ( 8 excessive equatorial diamet] on _! orbits1 #bh2 satellites1 libration 91 #fi2 rotation (1 #gj4 ,kane1 ,dr41 ,pol> ,sea discov]$ by1 #id2 cold ( ,nor!rn ,gre5l& m>k$ by1 #bdg4 ,kappa ,crucis1 clu/] ( col\r$ />s r\nd1 #dai4 ---- ,draconis1 se5 9 ! pole ( ! equator1 #hh1 #hi4 ,k>/51 ,mr41 impressions made on glass by electricity1 #bba4 ,kasan1 summ] & w9t] mean temp]ature (1 comp>$ ) ,ed9burgh1 #bdf1 #bdg4 ,kat]1 ,capta91 approximate l5g? ( ! p5dulum1 det]m9$ by1 #hi4 ,kempel51 ,m41 speak+-ma*9e inv5t$ by1 #aea4 ,kepl]1 pa?s1 revolutions ( planets discov]$ by1 #e2 8 law reg>d+ ! mean di/ances ( planets f ! sun1 #ai2 law (1 appli$ to calculat+ di/ances1 #ec1 #ed2 rapidity ( planet>y revolutions det]m9$ by 8 law1 #ff2 8 law f9d+ areas describ$ by heav5ly bodies1 ref]r$ to1 #cfj4 ,kew1 balloon asc5t f1 #aai4 ,knoblau*1 position ( ! magnecry/allic axis prov$ by1 #cdi4 ,k1 limit$ nature ( human1 #b4 ,kotzebue1 /ratum 9 ! ocean discov]$ by1 #aja4 ,kratz5/e91 ,m41 in/rum5t inv5t$ by1 articulat+ words1 #aea4 ,kupff]1 ,m41 obs]vations (1 on temp]ature1 #bdf4 ,la ,basilicata1 e>?quake 91 #bcd4 ,lacaille1 8 globul> nebul\s clu/]1 #dad2 nebula1 #dah4 ,la ,grange1 8 inve/igations into ! /ability ( ! sol> sy/em1 #bj1 #ba2 greate/ discov]y (1 #bc4 ,la ,hire1 phases 9 comets obs]v$ by1 #chj4 ,la ,place1 /ability ( ! sol> sy/em prov$ by1 #bj2 pr9ciple 9 a/ronomical calculations e/abli%$1 #bc2 angle ( incl9ation fix$1 #bd2 8 !ory acc\nt+ = accel]ation 9 ! moon's mean motion1 #cf1 #cg2 result ( obs]vations comp>$ ) 8 !ory ( ,jupit]'s satellites1 #ee2 !ory ( planet>y motion1 #fe1 #ff2 univ]sal epo* propos$ by1 #hg2 sci5tific obs]vations complem5t+ hi/orical records1 #hg2 date fix$ by1 = ! lun> tables ( ! ,indians1 #hh2 ju/ifies ,newton's !ory ( tides1 #if2 d5sity ( a liquid column e/imat$ by1 #aad2 action ( ! e>? on a comet1 #cei2 *ange 9 a comet's orbit1 #cfa2 cause ( error 9 ,clairaut's calculation po9t$ out by1 #cfc2 op9ion (1 z to ! comet ( #afhb1 #cgh4 8,lake ( ! ,gazelles0 ascrib$ to an effect ( reflection1 #aeg4 ,lal&e1 epo*s ( conjunctions comput$ by1 #db4 ,lambda ,h]culis1 g5]al motion ( ! />s det]m9$ by1 #dje4 ,l&1 dry1 comp>ative ext5t (1 on ! globe1 #bdb1 #bdd2 ext5t (1 9 diametrical opposition1 #bdd4 ,l&scapes 9 *i>oscuro1 produc$ by photography1 #bjg4 ,languages1 resemblances & analogies betwe51 #bee1 #bef4 ,lapl&1 arcs ( ! m]idian measur$ 91 #dh2 transit ( ,v5us obs]v$ 91 #ec4 ,l>o*e1 ,m41 8 exp]im5ts on transmission ( radiant heat1 #bei1 #bfa4 ,lassell1 ,mr41 satellite ( ,saturn discov]$ by1 #cb2 obs]vations (1 on ,uranus' satellites1 #cc2 8 discov]y ( ,neptune's satellite1 ib42 obs]vations on ,saturn's r+s1 #ff4 ,lat5t heat1 en]getic action (1 on matt]1 #bge-bgg4 ,latitude1 !1 ( a planet def9$1 mode ( obta9+1 #i1 #aj2 cause ( p]iodical inequalities 91 #ae2 p]turbations f action ( ! p]p5dicul> =ce1 #ah2 moon's motion 91 di/urb$1 #ce2 effects ( di/urbance1 #ch2 data (1 us$ 9 comput+ a planet's place 9 ! heav5s1 #eh-fj2 conditions ensur+ ! inv>iability ( geographical1 #gf1 #gg2 *ange effect$ by nutation 91 #ha2 climate n inv>iable 9 ! same1 #bci2 degrees (1 :]e dim9ution ( mean heat is mo/ rapid1 #bdd1 #bde2 ! same mean temp]ature 9 diff]5t1 #bdf1 #bdg2 ( w9e-gr[+1 #bej2 magnetic /orms v>y+ )1 #cde4 ,layang1 obs]vations made at1 #aajj ye>s be=e ! ,*ri/ian era1 #hh4 ,le ,sueur1 specific div]sity ( m>9e animals obs]v$ by1 #bed4 ,le ,v]ri]1 ,m41 pr9ciple ( ,la ,grange appli$ by1 #ba2 zone ( in/ability f\nd1 ib42 discov]y ( ,neptune1 #fb2 8 obs]vations on atmosph]ic waves1 #abb2 comets id5tifi$ by1 #cfb2 8 table ( comets' orbits1 ib4 ,l5ticul> nebul1 #dji2 haze surr\nd+ ! sun1 #dab4 ,leo1 nebul\s sy/em 91 #dag4 ,lon-,faucault1 ,m41 velocity ( light 9 air & wat] asc]ta9$ by1 #bjb4 ,l]ius1 banks ( alg f\nd by1 #bec4 ,leslie1 ,pr(essor1 compression ( air calculat$ by1 #gh2 exp]im5ts on radiation ( heat1 #beg4 ,lexel1 obs]vations (1 on ! comet ( #aggj1 #cfa1 #cfb4 ,libra1 ! five great planets 9 conjunction ne>1 #db4 ,librations ( ! moon1 ( ,jupit]'s satellites1 #fi2 ( ,c5tauri1 #cii4 ,li*51 r$1 gr[+ on sn[1 #bdi4 ,light1 rate ( its velocity1 #ca2 tru? d$uc$ f ! uni=mity ( its velocity1 #cb2 f ! ab]ration (1 ib42 p]iod requir$ to rea* ! e>? f ,c5tauri1 #ed2 action ( ! atmosph]e on1 #aec2 conditions regulat+ ! transmission & reflection (1 #aef2 loss (1 transmitt$ by ! horizontal /ratum1 #aeg2 effects ( transmission ?r\gh ! atmosph]e1 #aeh2 ,newton's analysis (1 #aei2 ,brew/]'s1 #afa2 ph5om5a disprov+ ,newton's !ory1 #afg1 #afh2 undulatory !ory1 #afh-agj2 conditions affect+ its int5sity & col\r1 #agj2 exp]im5ts te/+ ! mutual relations ( col\r &1 #aga-age2 law ( its absorption id5tical ) a law ( motion1 #age-agg2 repeat$ vibrations produc+ ! s5sation (1 #agh2 pol>iz$1 def9$1 #agi2 modes ( pol>ization1 sub/ances pol>iz+1 #agi-ahe2 accid5tal pol>ization (1 #aie2 degrad$1 or fluoresc5ce1 #aif2 objections to ! undulatory !ory analyz$ & disprov$1 #aii-bjb2 comp>ative velocity (1 9 air & wat]1 #bjb2 pictures produc$ by reflect$1 #bjc-bjg2 rays (1 indep5d5t ( heat1 #bad1 #bae2 comp>ative am\nts ( sol> & lun>1 #bbe2 diff]5t measures ( illum9ation f1 #bbg2 influ5ce (1 on vegetation1 #bdi2 col\r develop$ )\t ! influ5ce (1 #bec2 sep>at$ f heat by ,melloni1 #bfe2 produc$ by accumulation ( heat1 #bgj2 law regulat+ ! =ce ( artificial1 #bgi1 #bhj2 electrical1 #bhh1 #bhi2 produc$ by voltaic electricity1 #cjb2 /ratifications ( ! electric1 #cjf2 influ5ce ( magnetism & electricity on1 #cai1 #cbj2 ( comets1 #cgi-cha2 ( ! fix$ />s1 #dja-djd4 ,lightn+1 developm5t ( heat exhibit$ by1 #bgf1 #bgg2 exp]im5t %[+ ! velocity (1 #bhi2 !ory (1 #bib2 ! back /roke1 ib42 =ce ( ! direct /roke1 #bic2 %eet1 #bid2 effect (1 on ! compass1 #cab4 ,lime1 c>bonate (1 v>iety ( =m 9 its cry/als1 #ajg2 inv>iable =m ultimately assum$ by1 #aji4 ,l9es ( magnetic =ce1 #cch1 #cci2 exp]im5t asc]ta9+ ! =m (1 #cci1 #cdj2 t]re/rial1 #cda1 #cdb2 ext5sive c\rses (1 #cdd2 a connect$ sy/em1 #cde2 diamagnetic1 #cdh4 ,lion1 !1 conjunction ( planets 91 #db4 ,liquids1 balance ( =ces con/itut+1 #ajd1 #aje2 action ( capill>y attraction on1 #aac-aaf4 ---- possess+ ! prop]ty ( circul> pol>ization ( light1 #aij1 #aia-aic4 ,liquids1 conditions affect+ ! transmission ( radiant heat by1 #bfc2 evaporation f1 #bfi2 expansion (1 by heat1 #bga2 propagation ( heat 91 #bgc2 action ( heat z a me*anical =ce on1 #bge-bgg4 ,london1 ret>d+ ( ! tidal wave betwe5 ,ab]de5 &1 #id4 ----1 p5dulum vibrat+ 9 its latitude1 a /&>d ( measurem5t1 #hi2 fulgorites exhibit$ 91 #bic4 ,long1 ,dr41 8 attempt to measure di/ances ( fix$ />s1 #chh4 ,longitude1 mode ( reckon+ mean & true1 #i2 ( ! p]ihelion & ( ! epo* def9$1 #aj2 cause ( p]iodical p]turbations 91 #ad2 calculation f ! moon's influ5ce on ! sun's1 #ee2 data (1 us$ 9 comput+ a planet's place 9 ! heav5s1 #eh-fj2 *ange effect$ by precession & nutation 91 #ha4 ,lloyd1 exp]im5ts (1 9 pol>ization ( heat1 #bfd4 ,lubbock1 ,sir ,john1 !ory ( planet>y motion complet$ by1 #fd2 8 !ory ( %oot+ />s1 #dbc4 ,lumire c5dr1 def9ition (1 #bbg4 ,lun> di/ance1 def9$1 #dc4 ---- !ory1 mean di/ances obta9$ f1 #dc4 ---- tides ( ! t]re/rial atmosph]e1 #aba4 ,lundahles1 ,m41 motions ( heav5ly bodies inve/igat$ by1 #dje4 ,lupus1 position (1 #cij4 ,lussac1 ,gay1 ,m41 unit+ ( gases by volumes discov]$ by1 #aaa2 asc5t (1 9 a balloon1 #aah2 c\rse ( a lightn+ fla% asc]ta9$ by1 #bib4 ,lutetia1 diamet] (1 #ef4 ,lyell1 ,sir ,*>les1 8 !ory ( *anges ( temp]ature 9 ! nor!rn hemisph]e1 #ge2 annual numb] ( volcanic eruptions comput$ by1 #bcc2 volcanic ph5om5a relat$ by1 #bcd4 ,lyncis #ab1 a triple />1 #cie4 ,lyra1 a v>iable /> 91 #cia2 a d\ble />1 #cie2 nebula1 #daj4 ,ma*9]y1 relations (1 to =ce1 #cec4 ,mack9to%1 ,sir ,james1 quotation f1 illu/rat+ ! ess5tial advantages ( /udy1 #a4 ,macle>1 ,mr41 p>allax calculat$ by1 #chg4 ,madeira1 vegetation (1 #beb4 ,madras1 ,saturn's r+ discov]$ f1 #ff4 ,magellanic cl\ds1 !1 #dag1 #dah4 ,magnecry/allic action1 #cdi2 temp]ature affect+1 #ceb4 ,magnetic bodies1 diff]5ce 9 p[] (1 #cdg4 ---- elem5ts1 ! ?ree t]re/rial1 #cdc4 ---- equator ( ! e>?1 #cdc4 ---- m]idian1 !1 mean action ( =ces det]m9+1 #cdc4 ---- poles ( ! e>?1 #cdc4 ---- /orms1 #cdd2 v>y+ ) latitude1 #cde1 #cdf4 ,magnetism1 s\rce (1 #cah2 produc+ electrical ph5om5a1 #cbb1 #cbc2 rotatory motion a s\rce (1 #ccj2 classification ( sub/ances1 ) reg>d to _! susceptibility (1 #ccb2 resid+ 9 sub/ances aft] two mann]s1 #cce2 exp]im5t illu/rat+ ! =ces (1 #cch2 anti!sis1 its g5]al "*1 #cci2 =m ( its l9es ( =ce1 #cci1 #cdj2 analog\s prop]ties ( electricity & (1 #cdj1 #cda2 t]re/rial1 #cdb-cdg2 connexion betwe5 sol> & t]re/rial1 #cdd2 action (1 9 cry/als1 #cdi-cea2 influ5ce ( temp]ature 91 #ceb2 affect+ ela/icity ( matt]1 #ceb1 #cec2 a prop]ty ( ! e!real m$ium 7871 #cef1 #ceg4 ----1 electro1 discov]y1 importance ( ! sci5ce1 #cab2 rotation effect$ by1 #cac1 #cad2 electric int5sity measur$1 #cae2 action ( curr5ts 91 def9$1 #caf2 ,ampre's !ory (1 #cag1 #cah2 caus+ rotation ( pol>iz$ rays1 #cai2 action (1 on light1 #cbj2 accid5tal comb9ations1 #cdb2 influ5c+ metallif]\s deposits1 #cdf4 ,magneto-electricity1 pr9ciple sugge/+1 #cbb2 ma*9e con/ruct$ on ! pr9ciple (1 #cbe2 relation ( heat to1 #cbi4 ,magnets1 influ5ce (1 on electric light1 #cjg2 fi% possess+ ! p[] ( mak+1 #caa2 effect ( an electric /ream on1 #cab-cad2 obta9$ by electricity1 #cae2 p[] ( electro1 measur$1 #cae2 cyl9d]s act+ z1 #caf1 #cag2 produc+ electrical effects1 #cbb1 #cbc2 evolv+ electricity by rotation1 #ccj2 classification ( sub/ances 9 relation to1 #ccb2 pol>ity a prop]ty (1 #ccf2 effect on !mselves ( imp>t+ p>amagnetism1 #ccg2 exp]im5t %[+ ! l9es ( =ce (1 #cch2 prop]ties (1 inde/ructible by subdivision1 #cch1 #cci2 ! e>? reckon$ among1 #cdb2 planets reckon$ among1 #cdf2 action ( an electro1 on copp]1 #cea4 ,maguire1 ,capta91 8 obs]vations on magnetic /orms1 #cde1 #cdf4 ,malo1 ,/41 ris+ ( ! tide at1 #ih4 ,malus1 ,m41 discov]y ( pol>ization ( light by1 #aie2 attempts (1 to pol>ize heat1 #bfd4 ,malta1 obs]vations on ,saturn's r+s made at1 #ff4 ,man*e/]1 ?und]/orm ne>1 9 #ahce1 #bib4 ,mank9d1 di/9ct tribes (1 #bee2 limit$ p]ceptions (1 #bfg4 ,m>cet1 ,m41 rate ( increase 9 temp]ature bel[ ! e>?'s surface calculat$ by1 #bcj4 ,m>co ,polo1 atmosph]ic effects obs]v$ by1 9 asc5d+ m\nta9s1 #aah4 ,m>9e plants1 laws regulat+ _! di/ribution1 #beb1 #bec2 animals1 specific localities (1 #bed4 ,m>9]'s compass4 ,see ,compass4 ,m>s1 us$ 9 illu/rat+ ! possible effects ( ! radial di/ribut+ =ce1 #ai2 telescopic planets betwe5 ,jupit] &1 #bj1 #ba2 diamet] (1 #ba2 mean di/ance f ! sun1 ib4 note2 eclipse ( ,jupit] by1 #db2 p>allax f\nd by obs]v+ 8 oppositions1 p>allax (1 #ec2 int]nal /ructure1 #eh2 a/ronomical tables (1 #fc2 climate (1 #bbe2 approa* ( ! comet ( #aggj to1 #cfb2 comets hav+ _! p]ihelia 9 8 orbit1 #cha4 ,m>seilles1 transit ( a comet across ! sun obs]v$ f1 #cgd4 ,masses1 ( ! sun1 ( planets & _! satellites1 computations f9d+1 #ee1 #ef4 ,ma!matics1 use (1 9 ! /udy ( a/ronomy1 #b4 ,matt]1 !ory ( its con/itution1 #ajb2 hypo!ses z to =ces unit+ its p>ticles1 #ajc1 #ajd2 c\nt]balanc+ action ( ela/icity & cohesion1 #aje2 cry/allization common to all =ms (1 #aji2 inde/ructibility ( its p>ticles1 #aaj2 composition ( unorganis$ bodies1 subject to p]man5t law1 #aaj1 #aaa2 ag5t compos+ or decompos+1 #aab2 mode ( asc]ta9+ ! magnetism (1 #cce2 increatable1 inde/ructible1 #cec2 proportion (1 to sp>e1 #dbd4 ,matteucci1 ,m41 effect ( electricity on poli%$ silv] obs]v$ by1 #bba2 exp]im5t %[+ pol>ization by electricity1 #bhf2 d\bts (1 on ! pol>ity ( diamagnetism1 #cdh note2 exp]im5ts on magnetic action 9 cry/als1 #cej2 obs]vation on ! action ( compression1 #ceb4 ,maury1 ,lieut5ant1 calms nam$ by1 #abc4 ,measurem5t ( a/ronomical di/ances1 =mula assi/+1 #dc4 ,me*a91 ,m41 ,encke's comet se5 by1 #cfe4 ,me*anical equival5t ( heat1 #bge4 ---- eng9es1 incapable ( g5]at+ =ce1 #bgi4 ,m$it]ranean1 !1 conditions (1 %utt+ out ! tidal wave1 #ih2 hurricane 91 divid$ into two /orms1 #abf2 vegetation (1 #beb4 ,m$ium1 e!real1 transmitt+ magnetism1 #cdd2 d5sity (1 #cef2 probable relations (1 to gravity1 ib42 exp]im5t te/+ its magnetic prop]ties1 #cef1 #ceg2 functions (1 #ceg2 p]vad+ ! visible creation1 #ceh2 unsolv$ "q t\*+1 #cfe2 a cause ( accel]at$ revolutions ( comets1 #cff1 #cfg2 direction ( its increase 9 d5sity1 #cfg4 ,m$ium occupy+ space1 #dbd4 ,m$usa tribes1 !1 phosphoresc5t brilliancy (1 #bie4 ,melloni1 ,m41 exp]im5ts (1 9 photography1 #bad2 8 application ( ! pr9ciple ( !rmo-electricity1 #ccc2 exp]im5ts (1 9 transmission ( heat1 #beh-bfc2 fix+ ! maximum ( heat 9 ! sol> spectrum1 #bfd2 9 pol>ization ( heat1 #bfd-bff2 light sep>at$ f heat by1 #bfe4 ,melville ,isl&1 height ( ! !rmomet] 91 9 ,janu>y1 #bdg4 ,m]cury1 incl9ation ( 8 orbit to ! plane ( ! ecliptic1 #ba2 eclipse (1 #db2 cause ( 8 rotation unkn[n1 #fe2 ellipticity ( 8 orbit comp>$ ) ! t]re/rial1 #gd2 climate (1 #bbf2 comet revolv+ betwe5 ! orbits ( ,pallas &1 #cfg2 attraction (1 det]m9+ a comet's orbit1 #cfi2 comets revolv+ 9 8 orbit1 #cha2 velocity (1 #djj4 ----1 propagation ( heat 91 #bgc2 rotat+ by electricity1 #cad4 ,m]idian1 con/ant1 ( high wat]1 #ib4 ----1 mode ( det]m9+ ! magnetic1 #cdc4 ,m]idians1 size & =m ( ! e>? det]m9$ f1 #df2 measurem5t ( arcs1 #dg2 anomalies f local attraction1 #dh2 result ( ! computations1 #dh1 #di2 p]man5t1 ( ! moon1 #fi1 #gj4 ----1 magnetic1 influ5c+ ! direction ( metallic ve9s1 #cdf4 ,messi]1 comet ( #aggj obs]v$ by1 #cfa2 ,encke's comet se5 by1 #cfe2 nebula describ$ by1 #dji4 ,metallic salts1 action ( ! rays ( ! sol> spectrum on1 #bjc4 ---- spr+s us$ 9 con/ruction ( musical in/rum5ts1 #adc2 rods giv+ musical notes1 #add4 ,metallic surfaces1 pol>iz$ light reflect$ f1 #aic2 plates1 impressions on1 f bodies 9 contact )1 #bbj4 ,metals1 expansion (1 by heat1 #bga2 propagation ( heat 91 #bgd2 transmission ( electricity by1 #bhd2 electricity develop$ by oxidation (1 #bih2 det]m9+ ! appe>ance ( a spectrum ( voltaic flame1 #cjc2 di/ill$ 9 ! voltaic arc1 #cjd1 #cje2 electro-plat+ (1 #cji2 prop]ties (1 modify+ electric susceptibility1 #ccc2 magnetism an ag5t 9 ! =mation (1 #cdf4 ,meteor1 ! bur/+ ( a1 #aah4 ,meteors1 #dbj2 !ory (1 #dba-dbc4 ,meteoric /ones1 pro(s ( _! =eign orig91 #dbj1 #dba2 %[] (1 #dba1 #dbb4 ,mtre1 adopt$ by ! ,fr5* z _! unit ( l9e> measure1 #hi4 ,mica1 pol>ization by induction effect$ )1 #bhf4 ,milky ,way1 !1 describ$1 #che2 ,sir ,john ,h]s*el's description1 #che1 #chf2 8,coal ,sacks10 #chf2 />s compos+1 #bhf1 #bhg2 zone ( />s cross+1 #cij2 position ( v>iable />s ) reg>d to1 #cie2 cr[d+ 91 app>5t only1 #dje2 orbit 9 ! plane (1 #djf2 relation (1 to ! /ell> univ]se1 #djg2 nebula resembl+1 #dji2 its qu>t] ( ! heav5s1 #dad1 #dae2 divid+ ! nebul\s sy/em1 #daf1 #dag2 great nebula 91 #dah2 remote bran*es (1 #dai4 ,m9]als1 possess+ ! phosphoresc5t prop]ty1 #bid4 ,m9es1 cause ( increas$ temp]ature 91 #bbi2 gre5 plants gr[+ 91 #bec4 ,mira1 p]iods ( its fluctuations 9 lu/re1 #cij4 ,mirage1 suppos$ cause (1 #aeg4 ,miraldi1 rotation ( ,jupit]'s satellite det]m9$ by1 #gj4 ,mits*]li*1 ,m41 8 exp]im5ts on cry/als1 #ajg2 discov]ies1 #ajh2 exp]im5ts (1 9 expansions ( cry/als1 #bgb4 ,mo*a1 meteors fall+ at1 #dba4 ,moignot1 ,m41 cry/als compress$ by1 #ahi4 ,moi/ure1 an indisp5sable requisite = vegetation1 #bdh2 transmission ( electricity effect$ by1 #bhd1 #bhh4 ,molecul> pol>ity1 produc$ by electricity1 #bhb2 attraction1 electricity develop$ by de/ruction (1 #bhd4 ---- /ructure affect+ transmission ( electricity1 #cjc4 ---- vortices1 hypo!sis (1 acc\nt+ = ! absorption ( light1 #agg4 ,molecules1 mat]ial1 attraction & repulsion (1 #ajc2 effect ( ela/icity & cohesion on1 #ajd-ajf2 unit+ to =m cry/als1 #ajg-aji2 extreme m9ut5ess ( ultimate1 #aaj2 ( e!r1 modes ( _! vibration 9 natural & pol>iz$ light1 #aic2 9 fluoresc5t light1 #aif1 #aig2 images trac$ by ! mutual action (1 #bai-bbb2 arrangem5t (1 connect$ ) magnetism1 #cej-ceb4 ,mollusks1 di/9ct species (1 #bed4 ,monoc]otis #aa1 a triple />1 #cie4 ,monsoons1 !ory ( !1 #abc1 #abd4 ,mon?s1 antiquity (1 z a measure ( "t1 #he4 ,moon1 !1 =ce re/ra9+1 #d1 #e2 mean di/ance (1 f ! e>?1 #d2 results effect$ by h] ne>ness to ! e>?1 #g2 annual rate ( decrease 9 h] orbit's exc5tricity1 #ag2 av]age di/ance (1 f ! e>?'s c5tre1 p]iod ( h] circuit ( ! heav5s1 #cd2 h] p]iodic p]turbations1 #ce-ch2 causes assign$ = accel]ation ( h] mean motion1 #cf1 #cg2 eclipses (1 #ci1 #dj2 longitudes det]m9$ by obs]vations (1 #db1 #dc2 h] mean horizontal p>allax1 #eb2 s\rces :5ce h] mass may be det]m9$1 #ee1 #ef2 h] diamet]1 #ef2 rotation (1 #fh2 librations1 #fi2 m\nta9s1 #gj2 precession result+ f h] attraction1 #gi-ha2 influ5ce (1 produc+ tides1 #ia1 #ib1 #if-ih2 p]iod ( h] decl9ations1 #ig2 atmosph]ic equilibrium di/urb$ by h] attraction1 #aba2 cause ( h] app>5t increas$ magnitude 9 ! horizon1 #aeh2 photographic image (1 #bad2 comp>ative am\nt ( light emitt$ by1 #bbe2 cause ( ! r>ity ( h] atmosph]e1 #bbf2 increas$ int5sity ( light at full1 ib42 effect ( ! t]re/rial atmosph]e on heat radiat$ f1 #bbg2 cause ( accel]ation 9 ! mean motion (1 #cff2 light rea*+ ! e>? f1 #djd4 ,moorcr(t1 h]b>ium collect$ by1 #bej1 #bea4 ,mos]1 ,pr(essor1 mutual influ5ce ( bodies 9 contact te/$ by1 #bai1 #bbj4 ,mossotti1 ,pr(essor1 8 analysis to prove ! id5tity ( ! cohesive =ce ) gravitation1 #ajc1 #ajd2 8 def9ition ( gravity1 #cee4 ,motion1 a law ( ! univ]se1 #bgd2 p]petual1 impossible1 #bgi4 ,m\nta9s1 anomalies 9 measurem5t caus$ by1 #dh2 r>ity ( atmosph]e on1 #aah2 cause ( p]petual sn[1 #aai2 modes ( det]m9+ heights (1 #abj2 becom+ new c5tres ( motion 9 hurricanes1 #abf2 influ5ce ( *a9s on temp]ature1 #bda1 #bdb2 cause ( b\lem5s 91 #bga2 tops (1 fus$ by lightn+1 #bic4 ----1 lun>1 effect ( sol> rays pass+ betwe51 9 eclipses1 #da2 influ5ce (1 on ! moon's motions1 #if2 ?ree classes (1 #gj4 ,mu ,h]culis1 direction ( sol> motion ) reg>d to1 #djf4 ,multiple sy/ems ( />s1 #cie4 ,mundy1 ,capta91 mirage describ$ by1 #aeg4 ,music1 comp>ison in/itut$ ( sympa!tic notes 91 #b2 regulat$ undulations ( s\nd produc+1 #adb2 in/rum5ts (1 #adc2 exp]im5ts by means ( vibrat+ plates1 #add-adf2 sympa!tic vibrations1 #adg1 #adh2 exp]im5ts %[+1 #adh1 #adi4 ,musical in/rum5ts con/ruct$ by ,pr(essor ,:eat/one1 #adc4 ,naples1 comet discov]$ f1 #cgj4 ,nautical ,almanac1 computations = calculat+ longitudes1 #dc2 "t calculat$ by1 #hd4 ,navigation1 importance ( lun> motions 91 #db2 laws ( /orms to be obs]v$ 91 #abg1 #abh4 ,neap-tides1 #if1 #ii4 ,nebul1 numb] & g5]al aspect (1 #djg2 catalogues1 #djg1 #djh2 classes1 #djh2 irregul>1 #djh1 #dji2 ( def9ite =m1 #dji2 spiral1 #dji1 #daj2 annul>1 #daj1 #daa2 elliptical1 d\ble1 #daa2 di/ance ( a nebul\s /> discov]able1 #daa1 #dab2 aspect & col\r ( planet>y1 #dab2 elliptical common1 #dac2 globul> clu/]s1 #dac-dae2 resolution (1 #dae2 /> clu/]s1 #dae1 #daf2 probable law ( motion1 #daf2 di/ribution (1 #daf1 #dag2 ! ,magellanic cl\ds1 #dag1 #dah2 r\nd ,args1 #dah1 #dai2 remote sy/ems1 #dai2 invisible sol>1 #dba2 meteors fall+ f1 #dbb4 ,nebul\s appe>ances ( a comet1 #cfd2 ext5t (1 matt] surr\nd+ a comet1 #cgc2 its v>iable brilliancy1 #cgd2 appe>ances r\nd ! sun1 #dab4 ---- />s1 #daa1 #dab4 ,ne$le1 magnetiz$1 effect ( ,voltaic electricity on a1 #cab1 #cac2 susp5d$ by means ( electricity1 #cad2 condition ( its deviation by an electric curr5t1 #cag4 ,negative electricity def9$1 #bhb2 mode ( excit+1 #bhc4 ---- impressions 9 photography1 #bjd4 ,neptune1 p]iodical v>iations 9 8 orbit1 #bb2 revolution ( 8 satellite f ea/ to we/1 #cc2 remot5ess (1 #ed2 anticipation ( discov]y1 #fa2 orbit & motions (1 det]m9$1 #fb2 8 diamet]1 mean di/ance f ! sun1 #fc2 temp]ature (1 #bbe2 action (1 on ,halley's comet1 #cfc4 ,neutral phosphate ( soda1 its cry/als1 #aji4 ,new ,mexico1 monsoons occasion$ by its des]ts1 #abd4 ,newton1 ,sir ,isaac1 /eps ( 8 argum5t = ! univ]sal influ5ce ( gravitation1 #c2 8 discov]ies ( modes ( attraction1 #d2 motions ( bodies project$ 9 space1 asc]ta9$ by1 #e2 =m ( a fluid mass 9 rotation asc]ta9$1 #de2 problem occupy+ a/ronom]s s9ce1 #fd2 discrepancy betwe5 8 !ory ( tides & obs]vations1 #if2 comp\nd nature ( :ite light prov$ by1 #aei2 8 analysis ( ! sol> spectrum disput$1 #afa2 8 !ory ( light disprov$1 #afg2 measurem5ts ( col\r$ rays1 #agb1 #agc2 scale ( col\rs1 #agd2 decisive exp]im5t disprov+ ! !ory ( light1 #bjb2 rem>ks on ! transmission ( gravity1 #cee4 ,niag>a1 ! falls (1 n indep5d5t ( ! influ5ce ( a/ronomy1 #a4 ,nickel1 sulphate (1 *ange 9 its cry/als1 :5 expos$ to ! sun1 #ajg4 ,niepc1 ,m41 photographic pictures r5d]$ p]man5t by1 #bjd2 discov]y 9 photography sugge/$1 #bjg2 col\rs ( images ( ! sun tak51 #bac2 exp]im5ts by1 on saturation ( sub/ances ) light1 #bif4 ,nimes1 discov]y ( a telescopic planet at1 #ba4 ,nitrog51 proportion (1 9 ! atmosph]e1 #aag2 spectrum f1 #cjc2 iron volatiliz$ by ! ,voltaic arc 91 #cjd2 unaffect$ by magnetism1 #cdd4 ,nobili1 ,m41 direction ( electric curr5ts asc]ta9$ by1 #ccc4 ,nodes1 asc5d+ & desc5d+1 ( a planet def9$1 #i2 movem5t ( _! l9es 9 secul> di/urbances1 #ad2 advance & recession (1 #ah2 suppos$ recession (1 on ! equator ( ! sol> sy/em1 #bd2 ( ! moon1 p]iod ( _! sid]eal revolution1 #cg2 secul> inequality affect+1 #ch2 influ5ce (1 on eclipses1 #ci2 cause ( _! rapid motion1 #ee2 po9ts ( re/ on a vibrat+ /r+1 #ada2 9 ! vibrations ( an undulat+ column ( air1 #adb2 9 vibrations ( solids1 #adg4 ,non-conductors ( electricity1 #bhd1 #bhe4 ,non-electrics1 #bhe4 ,nor? ,atlantic1 !1 w9ds 91 #abd4 ---- ,pol> ,ocean1 tide 9 !1 #id4 ,norway1 c\rse ( ! tidal wave to1 #id4 ,notes 9 music1 #adb1 #adc4 ,nubecula1 ,major & ,m9or1 #dag1 #dah4 ,nucleus1 ( ,halley's comet1 *anges 9 its aspect1 #cfd2 disappe>ance (1 9 ,encke's1 #cfi2 division1 9 ,biela's1 #cfi1 #cgj2 diaphan\s1 #cgc2 solidity (1 te/$1 #cgd2 ( a spiral nebula1 #dji4 ,nuremburg1 obs]vations on a comet f1 #cgj4 ,nutations produc$ by ! moon's ne>ness to ! e>?1 #g2 9 ,jupit]'s equator1 #bi2 9 ! planet>y axes1 #ff2 effect (1 on ! pole ( ! equator1 longitudes & latitudes alt]$ by1 #ha4 ,nysa1 ne>ness ( its orbit to ! e>?1 #ba4 ,oaks1 range (1 ne> ! equator1 #bej4 ,occultation1 c5tral1 by ,halley's comet1 #cfd2 geographical position asc]ta9$ by1 #chd2 prospective1 by a sun ( ,c5tauri1 #djj4 ,occultations ( />s1 #db1 #dc4 ,ocean1 !1 d5sity & mean dep? (1 #ea2 mean d5sity1 comp>$ ) ! e>?'s1 #gg2 its =m 9 equilibrio1 :5 revolv+ r\nd an axis1 #ib2 sol> & lun> attraction di/urb+ its equilibrium1 ib42 inequalities 9 p]iodic motions1 #ic2 motions ( ! tidal wave 9 #ie2 /ability ( its equilibrium1 #ajj2 circulation ( curr5ts 91 ib42 /ratum ( con/ant temp]ature 91 #aja2 zones (1 ib42 decrease & increase ( temp]ature ) dep?1 #bca2 absorption & radiation ( heat by1 #bdb2 electricity evolv$ f1 #bia4 ,oceans ( light & heat1 processes produc+1 #bbe4 ,o*otzk1 ! sea (1 depression ( ! b>omet] obs]v$ 91 #abj4 ,octob]1 #ahcb1 position ( ,saturn's r+s 91 #fg4 ,olb]s1 ,m41 computations = a comet by1 #cfg2 p]iod ( 8 comet1 #cgj2 comet ( #ahaa obs]v$ by1 #cgd4 ,opaque bodies1 mode 9 :i* heat is develop$ 91 #bbg4 ,ophiu*i #gj1 anomalies 9 ! motions (1 #djj4 ,ophiu*us1 clu/]s ( ! ,milky ,way betwe5 ! ,%ield &1 #chg2 new /> disappe>+ f1 #cic4 ,optic axis1 !1 ( cry/als1 #ahc2 ph5om5a exhibit$ by transmission ( a pol>iz$ ray along1 #ahg1 #ahh2 affect$ by compression1 #ahi4 ,orbit1 !1 ( ! e>?1 attraction int5sifi$ by its dim9i%$ exc5tricity1 #cg2 exc5tricity (1 affect+ temp]ature1 #gd1 #ge2 cross$ by comets1 #cfh4 ---- ( ! moon1 =ce rul+1 #d2 its exc5tricity1 #cd2 *anges 91 #ce2 its incl9ation to ! plane ( ! ecliptic1 #gi4 ---- ( a nebula1 #dae4 ---- ( ! sol> sy/em1 #dje1 #djf4 ,orbits ( comets1 subject to v>iation1 #cfa2 examples1 #cfa-cfc2 prospective *anges 91 #cfi1 #cgj2 ( ,donati's1 #cgi2 =ces det]m9+ _! =ms1 #chb1 #chc4 ---- ( d\ble />s1 #cif-djj4 ---- ( planets1 =ce regulat+ a planet's velocity 91 #h2 measurem5t ( _! exc5tricity1 #i2 sev5 elem5ts (1 det]m9+ _! position 9 space1 #aj2 unequal movem5ts 91 #ae2 v>iation f elliptical to circul>1 #ag2 secul> v>iations (1 9 incl9ation to ! plane ( ! ecliptic1 #ah1 #ai2 /able & un/able 9 =m1 #ba1 #bb2 influ5ce ( ! e!real m$ium on1 #bb2 pr9ciple facilitat+ obs]vations on secul> inequalities1 #bc1 #bd2 revolutions ( ,saturn comp>$ ) ,jupit]1 #be2 p]iodic inequality increas$ by secul> v>iations 9 _! elem5ts1 #bf2 comets revolv+ 91 #cha1 #chb2 cause ( div]sity 9 =m (1 #chb4 ,orbits ( satellites1 =ms ( ,jupit]'s1 #bg2 _! incl9ations1 #bh2 incl9ations ( ,saturn's1 #cb2 positions ( ,uranus's1 #cc2 =ms ( data 9 comput+ a planet's place 9 ! heav5s1 #ei4 ,or9oco1 ! cat>acts ( !1 he>d by day & by night1 #ace2 area occupi$ by =e/s on1 #bdc4 ,orion1 ! ,milky ,way betwe5 ,ant9\s &1 #che1 #chf2 position (1 #cij2 v>iable /> 91 #cic1 #cid2 multiple sy/em 91 #cie2 nebula 91 #djh4 ,o]/$1 ,pr(essor1 discov]y (1 sugge/+ ! !ory ( electro-magnetism1 #cab2 sci5ce f\nd+ ! reputation (1 #caf4 ,oscillations1 wide-spread+1 produc$ by gravitation1 #b2 me*anical pr9ciple affect+ small1 #aa2 ( ! s9es & cos9es ( circul> arcs1 #bj2 inv>iable plane :5ce !y may be e/imat$1 #bd2 ( ! p5dulum ret>d$1 #cb2 ( ! p5dulum1 exp]im5ts f\nd$ on1 #ej1 #ea2 exp]im5ts te/+ ! e>?'s d5sity1 #eg2 a measure ( "t1 #hc2 produc$ by tides1 #ie1 #if2 in/rum5ts measur+ atmosph]ic1 #aac2 b>omet] affect$ by p]iodic atmosph]ic1 #abj1 #abb2 ( e>s ( corn1 #abi1 #acj2 produc+ musical notes1 #adj-adb2 in/ances ( =c$ sympa!tic1 #adh2 caus+ vicissitudes 9 climates1 #bdg2 ( ! p5dulum1 di/urb$ by effects ( temp]ature1 #bgb2 measur+ v>iation ( electrical int5sity1 #bhg4 ,otto1 ,m41 motions ( ! heav5ly bodies obs]v$ by1 #dje4 ,oxidation ( metals1 electricity develop$ by1 #bih2 by ! ,voltaic dis*>ge on poli%$ silv]1 #cje4 ,oxides decompos$ by electricity1 #cjg2 alkalies resolv$ into metallic1 #cjg4 ,oxyg51 9 cry/als1 #aji2 proportion (1 9 wat] & c>bonic oxide1 #aaa2 9 ! atmosph]e1 #aag2 *emical comb9ation )1 evolv+ light & heat1 #bgj2 action ( electricity on1 #bhd2 electricity af=d$ by comb9ation ( metals )1 #bih2 spectrum f1 #cjc2 sep>at$ f wat] by electricity1 #cjg2 p>amagnetic1 #cdd4 ,ozone1 produc$ by electricity1 #bhd4 ,pacific ,ocean1 mean dep? (1 #gg2 c\rse ( tidal waves d[n1 #ic2 mean dep? (1 #if2 curr5ts1 #ajj4 ,pad]born1 fulgorites f1 #bic4 ,pallas1 incl9ation ( its orbit to ! ecliptic1 #aj2 diamet] (1 #ba2 a/ronomical tables1 #fc2 ellipticity ( its orbit comp>$ ) ! t]re/rial1 #gd2 height ( its atmosph]e1 #bbf2 comet revolv+ betwe5 ! orbits ( ,m]cury &1 #cfg4 ,pan's pipes1 vibrations 9 ! air pass+ ov]1 #adb4 ,p>abolic motion1 ratio ( =ces procur+1 #chb4 ,p>allax ( ! sun1 circum/ance fav\rable to its correction1 #ba4 ---- ( an object def9$1 #dc4 ----1 def9ition1 mode ( asc]ta9+1 #eb2 di/ances comput$ f1 #eb-ed2 calculation f ! moon's horizontal1 #ee4 ---- ( fix$ />s1 #chg-cij4 ---- ( meteors1 #dba1 #dbb4 ,p>amagnetic sub/ances1 #cce1 #ccf4 ,p>amagnetism def9$1 #cce2 sub/ances x is resid5t 91 #ccf2 modes ( imp>t+1 ib42 a dual p[]1 ib42 imp>t$ by induction1 #ccg2 law ( its int5sity1 #cch2 a prop]ty ( oxyg51 #cdd2 9 anti!sis to diamagnetism1 #cdg2 neutral sub/ances obta9$ by comb9ations ( diamagnetism &1 ib42 ,dr4 ,tyndall's exp]im5ts on pol>ity (1 #cdh2 dep5d5t on arrangem5t ( molecules1 #cej1 #cea2 affect$ by compression1 #cea2 tru? e/abli%+ its id5tity ) diamagnetism1 #cef1 #ceg4 ,p>a!rmic rays1 analyz$ by ,sir ,john ,h]s*el1 #bag-bai4 ,p>is1 v>iation 9 l5g? ( ! p5dulum at1 #ea2 mean annual temp]ature1 #bbh2 temp]ature ( an ,artesian well 91 #bcj4 ,pa?s ( comets1 #cei1 #cfj2 secrets disclos$ by _! exc5tricities1 #cfe4 ,p>ry1 ,sir ,edw>d1 turn$ back by ! ,pol> curr5t1 #aja2 mean temp]ature calculat$ f obs]vations (1 #bde2 !rmomet] at ,melville ,isl& m>k$ by1 #bdg4 ,pauxis1 ! ,/raits (1 ebb & fl[ ( ! sea 91 #ih4 ,peel1 ,sir ,william1 ?und]/orm exp]i5c$ by1 #bic1 #bid4 ,pegasus1 nebul\s region (1 #dag4 ,p5dulum1 !1 pr9ciple equaliz+ its oscillations1 #ej2 ! e>?'s figure calculat$ by1 #ej1 #ea2 exp]im5ts asc]ta9+ ! e>?'s d5sity1 #eg2 iso*ron\s1 a measure ( "t1 #hc2 a /&>d ( ! measure ( ext5sion1 #hi2 !1 a connect+ l9k betwe5 "t & =ce1 #id2 inv5tions to neutralise ! effects ( temp]ature1 #bgb4 ,p5umbra1 9 lun> eclipse1 bread? ( space occupi$ by1 #dj4 ,p]igee1 ( ! lun> orbit1 p]iod ( its revolution1 #cg1 #ch2 cause ( its rapid motion1 #ee4 ----1 sol>1 p]iods ( its co9cid5ce ) ! equ9oxes1 #hf4 ,p]ihelion ( a planet's pa? def9$1 #af4 ---- ( ! e>?'s orbit1 its position regulat+ ! l5g? ( seasons1 #gd4 ,p]iodic inequalities ( planets1 #ac1 #ad2 law f :i* !y are d$uc$1 #bd1 #be2 ( ,jupit]'s satellites1 #bh1 #bi2 lun>1 #ce4 ,p]k9s1 ,mr41 exp]im5ts (1 te/+ ! laws ( compression1 #gh4 ,p]on1 ,m41 specific div]sity ( m>9e animals ass]t$ by1 #bed4 ,p]p5dicul> =ce1 ! s\rce ( p]iodic inequalities1 #ae2 effects produc$ by1 #ah4 ,p]petual motion1 inv>iable proportion betwe5 heat & =ce preclud+1 #bgi4 ,p]seus1 v>iable /> 91 #cij1 #cia4 ,pet]s1 ,mr41 comet discov]$ by1 #cgj2 p>allax ( ,lyr1 #chh1 #chi2 di/ances ( fix$ />s calculat$1 #chi2 8 !ory ( ,sirius' irregul> motions1 #cib2 sun's motion prov$ by1 #dje4 ,petit1 ,m41 obs]vations (1 on meteoric satellites1 #dbc4 ,p]u1 arcs ( ! m]idian measur$ 91 #dh4 ,phases ( ! moon1 regulat+ returns ( eclipses1 #ci4 ,ph5om5a1 ( effects ( light 9 eclipses1 #da1 #db2 appli$ to comput+ longitudes1 #dc2 caus$ by tidal oscillation1 #if2 f =ce ( cohesion1 #ajf1 #ajg2 ( capill>y attraction1 #aae2 produc$ by refraction & reflection1 #aee-aeg2 by pol>ization ( light1 #ahf-aij2 exhibit$ 9 fluoresc5ce ( light1 #aif1 #aig2 result+ f int]action ( rays & molecules1 analog\s to effects ( photography1 #bai-bbb2 phosphoresc5t1 #bie1 #bif2 ( galvanism1 #caj2 ( magnetism1 #cce1 #cde-cdh2 magnecry/allic1 #cdi1 #cej2 exhibit$ by comets1 #cfc1 #cfd1 #cfi1 #cgj1 #cgb-cgf2 by ! ,milky ,way1 #che-chg2 by v>iable />s1 #cij-cic2 by d\ble />s1 #cig-dja2 by nebul1 #dji-dae1 #dag-dai2 by meteoric %[]s1 #dba1 #dbb4 ,phosphoresc5ce1 rays ( ! sol> spectrum excit+1 #baf2 cause (1 9 ! sol> spectrum1 #bag2 excit$ by electricity1 #bid2 fi% possess+ ! prop]ty (1 #bie2 ! gl[ dis*>ge1 #bie1 #bif2 exp]im5ts inve/igat+ ! nature (1 #bif4 ,photo-galvanic engrav+1 #cji4 ,photography1 fir/ sugge/ions1 #bjc2 discov]ies & improvem5ts 91 #bjd-bjg2 conditions affect+ ! *emical prop]ties ( rays produc+1 #bjg1 #bjh2 images ( ! sol> spectrum obta9$ by1 #bjh-baj2 col\r$ copy ( an engrav+1 #baa2 ph5om5a 91 sugge/+ an absorptive action 9 ! sol> atmosph]e1 #bab1 #bac2 *emical en]gy produc+1 di/9ct f light & heat1 #bad2 exp]im5ts by means (1 te/+ ! prop]ties ( rays1 #bah1 #bai2 exp]im5ts on action ( light1 heat1 electricity1 produc+ results analog\s to effects (1 #bai-bbc4 ,photosph]e1 !1 ( ! sun describ$1 #bbd4 ,physical ,sci5ces1 ! mo/ ext5sive example ( _! connection1 mode ( its op]ation1 #a4 ,pi ,h]culis1 direction ( sol> motion ) reg>d to1 #djf4 ,pisces1 nebul\s region (1 #dag4 ,planet>y motion1 repres5tation (1 #ad4 ---- nebul1 #dji2 appe>ance (1 #dab4 ,planets1 pa?s r\nd ! sun describ$ by1 #e2 law det]m9+ _! revolutions1 ib42 =ces adju/+ _! =ms1 #f2 _! motions 9 elliptical orbits1 mean di/ance f ! sun1 #h2 mode ( obta9+ ! place (1 9 _! orbits1 #i2 computations giv+ ! place (1 9 space1 #aj2 di/urbances f reciprocal attraction affect+1 comp5sations1 #ac-ai2 telescopic1 #bj1 #ba2 p]turbations 9 ! mean motions (1 #be1 #bf2 influ5ce (1 on lun> motions1 #cf2 eclipses & conjunctions (1 #db2 =mula f9d+ _! masses1 #ee2 _! diamet]s1 #ef2 mass ( ! telescopic1 comp>$ ) ! moon1 ib42 comp>ative d5sity1 #eh2 me?od ( comput+ _! places1 #eh-fd2 discov]y (1 #fa-fc2 explod$ !ory t\*+ telescopic1 #fc2 p]iods ( _! rotations1 #ff2 v>iation & position ( ! plane ( ! ecliptic produc$ by1 #gi2 its effect on ! equ9octial po9ts1 #hj2 climates (1 #bbe1 #bbf2 probably magnets1 #cdf2 con/ant velocity ( _! mean motions1 #cff4 ,plants1 di/ribution ( kn[n species ov] ! globe1 #bdi1 #bej4 ,plates1 vibrat+1 exp]im5ts by means (1 #add-adf4 ,plateau1 ,m41 exp]im5ts (1 on col\r1 #afe1 #aff4 ,plat9a1 inc&esc5t1 us$ z a s\rce ( heat1 #bfj4 ,plat9um1 exp]im5t produc+ spontane\s combu/ion (1 #aab1 #aac4 ,playfair1 ,pr(essor1 quot$ 9 ref]5ce to ,la ,grange's discov]y1 #bc4 ,pleiades1 !1 nebul\s />s1 #dae4 ,plck]1 ,pr(essor1 discov]ies (1 9 ! action ( magnetism 9 cry/als1 #cdi4 ,plumb-l9e1 deviations (1 f local attraction1 #dh2 e>?'s d5sity calculat$ f a deviation (1 #eh4 ,po9sot1 ,m41 ,la ,place's discov]y ext5d$ by1 #bc2 comp>ison by1 #bd4 ,po9t1 ready escape ( electricity f a1 #bhh4 ,poisson1 ,m41 decisions (1 on ! ph5om5a ( capill>y attraction1 #aad4 ,pol> bas91 probable temp]ature (1 #bde1 #bdf4 ---- />1 *ange ( position 9 !1 #ha1 #hb4 ---- vegetation1 contra/$ ) tropical1 #bdh4 ,pol>ity1 produc$ by electricity1 #bhb2 ( magnets def9$1 #ccf2 induc$ 9 iron1 #ccg2 its anti!tical manife/ations (1 #cci2 inv>iably dual1 #cda2 ( diamagnetic sub/ances1 #cdg1 #cdh4 ,pol>ization ( light1 def9ition (1 #agi2 refract$ by v>i\s sub/ances1 #ahj-ahc2 by reflection1 #ahd2 angles (1 #ahe2 ph5om5a exhibit$ by transmission ?r\gh analyz+ m$ia1 #ahf-ahh2 circul>1 #ahi-aia2 !ory ( circul> & elliptical1 #aib1 #aic2 sub/ances produc+1 #aic1 #aid2 !ory ( col\r$ images =m$ by1 #aid2 accid5tal1 #aie2 discov]y (1 ib42 degrad$ light incapable (1 #aih2 communicat+ electricity1 #bbj2 plane ( motion ( vibrations 91 #bbc4 ,pol>ization ( heat1 fir/ attempts1 #bfd2 successful exp]im5ts1 #bfe-bfg4 ---- ( electricity by induction1 #bhf4 ----1 exp]im5t %[+ ! action ( magnetism on1 #cai2 affect$ by me*anical compression1 #ceb4 ,poldice m9e1 !1 temp]ature ( ! wat] pump$ f1 #bbi4 ,poles1 !1 cause ( ! flatt5+ ( a sph]oidal mass at1 #f2 diamet] ( ,jupit] at1 #bg2 exp]im5t det]m9+ ! increase ( gravitation t[>ds1 #di1 #ej2 !1 drift+ ( ice f1 #ajj1 #aja2 ( maximum cold1 c5tres ( ! iso!rmal l9es1 #bde1 #bdf2 nature ( magnetic =ce di/+ui%$ by1 #ccb2 f\r t]re/rial1 ( maximum magnetic =ce1 two magnetic1 #cdc4 ,pollux1 an optically d\ble />1 #dja4 ,port ,b[5 ,h>b\r1 transmission ( s\nd across1 :5 froz51 #acf4 ,positive electricity1 def9$1 #bhb2 mode ( excit+1 #bhc4 ---- impressions 9 photography1 #bjd4 ,p\illet1 ,m41 8 e/imate ( ! mean temp]ature ( space1 #aai2 quantity ( sol> heat receiv$ by ! e>? comput$ by1 #bch2 data furni%$ by1 to ,pr(essor ,?omson1 #bgi2 developm5t ( electricity inve/igat$ by1 #bia4 ,p[ell1 ,bad51 sub/ances produc+ elliptical pol>ization enum]at$ by1 #aic2 disp]sion ( light acc\nt$ = by ! undulatory !ory1 #bjj1 #bja2 exp]im5ts 9 transmission ( radiant heat1 #bfb2 attempts to pol>ise heat1 #bfd4 ,p[]1 ,mr41 undulations produc+ fluoresc5t light comput$ by1 #aig2 law ( sol> rays act+ on m$ia1 #aih4 ,prsepe1 !1 9 ,canc]1 #dae4 ,precession1 a1 9 ! equ9oxes ( planets1 its cause1 #ff2 mean1 ( ! equ9octial po9ts1 def9$ & calculat$1 #hj2 influ5ce (1 on ! pole ( ! equator1 on longitudes1 #ha4 ,pressure1 electricity elicit$ by1 #bhc1 #bhd2 law ( electrical1 #bhh4 ,pr9cipato ,cit]iore1 e>?quake 91 #bcd4 ,prisms1 sol> spectrum =m$ by1 #aei2 neutraliz+ effects ( col\r1 #afd2 ( br[n t\rmal9e1 light pol>iz$ by1 #ahj2 resolution ( ! pure :ite sunbeam by1 #bbb2 sub/ance (1 det]m9+ ! po9t ( maximum heat 9 ! sol> spectrum1 #bfc1 #bfd2 electrical light analys$ by1 #bhh4 ,problem det]m9+ ! motions ( translation ( ! cele/ial bodies1 #aa2 ( ! ?ree bodies1 #eh2 ! h>de/ a/ronomical1 #ib4 ,procyon1 light (1 #djb4 ,proportion1 def9ite1 ! law (1 9 mix+ sub/ances1 #aaa1 #aab4 ,protoxides ( metals1 _! cry/als1 #aji4 ,prussia1 ,ea/]n1 fulgorites f1 #bic4 ,ptolemy1 decrease 9 ! incl9ation ( ,jupit]'s orbit s9ce ! age (1 #ai2 discov]y ( ! ,evection by1 #ce2 ,indian lun> tables calculat$ 9 8 "t1 #hh2 horoscope ascrib$ to ! age (1 #hi2 effects ( refraction obs]v$ by1 #aee2 col\r ( ,sirius 9 8 "t1 #dja4 ,quadratures1 ! equation ( ! c5tre 91 #i2 lun> orbit augm5t$ 91 #ce2 tides affect$ by ! moon 91 #if4 ,quadrup$s1 di/ribution ( di/9ct species (1 #bee4 ,qu>tz1 cry/allis$1 light pol>iz$ circul>ly by1 #ahi1 #aij2 v>ieties ( pol>ization exhibit$ by1 #aic4 ,quebec1 extremes ( temp]ature f\nd 91 #bdg4 ,qu99e1 sulphate (1 produc+ fluoresc5ce ( light1 #aig4 ,radial =ce produc+ p]iodical *anges 9 relative positions ( ! heav5ly bodies1 #ae2 effects produc$ by1 #af1 #ag2 pr9ciple neutralis+ its ultimate result1 #ai1 #bj4 ,radiation ( heat1 laws regulat+1 #beg2 univ]sal f sub/ances1 #bfh2 natural ph5om5a result+ f1 #bfi2 sl[ decrease ( ! e>?'s c5tral heat f1 #bcb2 influ5ce (1 on temp]ature1 #bci2 p[] (1 9 wat] comp>$ ) dry l&1 #bdb2 ( heat1 a transf] ( motion1 #bgg4 ,radii vectores1 signification (1 #h2 areas describ$ by1 #aj2 =ce di/urb+ 9 ! direction (1 #ad1 #ae4 ,ragona-,sc9a1 ,m41 8 !ory ( rayless l9es 9 ! spectrum1 #afc4 ,ra91 =ce %ap+ drops1 #ajf2 cause ( p]iodic tropical1 #abc2 region (1 #abd2 !ory ( its =mation1 #bgj2 an electric conductor1 #bib4 ,rank9e1 ,mr41 8 !ory ( ! /ructure ( matt]1 #ajd2 8 !ory ( ! absorption ( light1 #agg4 ,rays1 common nature & common prop]ties (1 #bfh4 ---- ( heat1 exi/+ indep5d5tly ( lum9\s1 #beg2 laws ( transmission (1 #beh2 analogy betwe5 transmission ( lum9\s rays &1 #bei2 temp]ature ( _! s\rce affect+ transmission1 #bfj2 v>y+ 9 nature ) _! orig91 #bfa2 transmitt$ ?r\gh col\r$ glass1 #bfb2 trav]s+ v>i\s m$ia1 ib42 subject to refraction & reflection1 #bfc2 pol>iz$1 #bfe-bfg2 absorption & reflection (1 #bfh2 rotation ( pol>iz$1 caus$ by magnetism1 #cai4 ---- ( light1 b5t by pass+ f r>e into d5se m$ia1 #aec2 p>tial & total reflection (1 #aef2 loss (1 by obliquity ( incid5ce1 #aeh2 !ory ( _! transmission & absorption1 #aei-afa2 comp>ative refrangibility (1 #afc2 exp]im5ts on disp]sion (1 #afd2 pr9ciple det]m9+ _! col\r1 #agj1 #aga2 transmission (1 9 glass or wat]1 #agg1 #agh2 conditions ( pol>iz$1 #agi2 d\ble refraction1 #aha-ahc2 pol>iz$ by reflection1 #ahd1 #ahe2 col\r$ images produc$ by int]f]5ce (1 #aid1 #aie2 int]nal disp]sion (1 #aie-aih2 heat1 light1 *emical action1 indep5d5t prop]ties (1 #bad1 #bae2 undulations con/itut+1 #bbc2 conditions modify+ ! p[] ( sol>1 to produce heat1 #bcg2 transmitt$ indep5d5tly ( calorific rays1 #beh2 magnetiz+ ( pol>iz$1 #cah1 #cai4 ,rays1 sol>1 effect produc$ by _! refraction 9 lun> eclipse1 #dj2 pass+ betwe5 lun> m\nta9s 9 sol> eclipse1 #da4 ---- ( ! sol> spectrum1 _! *emical prop]ties1 #bjc2 v>y+ *emical en]gy1 #bjg1 #bjh2 v>y+ nature ( _! action1 #bjh2 peculi> *emical action ( ! r$1 #bji-baa2 deoxydat+ & oxydat+ action (1 #baa1 #bab2 exp]im5ts detail$1 #bab-bae2 new1 obscure1 detect$ by ,sir ,john ,h]s*el1 #bag4 ,r$ ,sea1 !1 tide 91 #ih4 ,reflection ( waves ( s\nd1 #acg1 #ach2 ( rays at surfaces ( /rata diff]+ 9 d5sity1 ph5om5a occasion$ by1 #aef1 #aeg2 affect+ col\r1 #afj2 motion ( a ray ( light 91 #agg2 light pol>iz$ by1 #ahd1 #ahe2 elliptical pol>ization produc$ by1 #aic2 heat pol>iz$ by1 #bff2 ( radiant heat f surfaces1 #bfh4 ,refraction ( ! sun's rays 9 lun> eclipses1 #dj2 ( waves ( s\nd1 #ach2 ( light by ! atmosph]e1 #aec1 #aed2 mode ( e/imat+1 9 case ( cele/ial bodies1 #aee2 =mul obta9+ 9 case ( t]re/rial objects1 ib42 ph5om5a occasion$ by1 #aee1 #aef2 col\rs decompos$ by1 #aei1 #afj2 produc$ )\t col\r1 #afd1 #afe2 p[] (1 9 m$ia affect+ ! ela/icity ( ! lum9\s e!r1 #agg2 ( a pol>iz$ ray1 #ahj2 d\ble1 #aha1 #ahb2 ,fresnel's !ory (1 #ahc2 dim9i%$ capability ( produc+ fluoresc5ce1 #aif2 capability (1 9 rays1 affect+ _! *emical action1 #bji-bab2 effect (1 on ! lun> atmosph]e1 #bbf2 influ5ce (1 on transmission ( heat1 #beh2 ( rays ( heat1 #bfa-bfd2 heat pol>iz$ by1 #bff4 ,refrangibility1 sub/ances dim9i%+1 ( light1 #aif2 affect+ ! *emical action ( rays1 #bji-bab2 affect+ radiation ( heat1 #beg2 affect+ transmission ( radiant heat1 #bfa-bfc4 ,rei*1 ,pr(essor1 temp]ature ( m9es obs]v$ by1 #bbh2 mean increase calculat$ by1 #bcj4 ,reptiles1 di/ribution ( di/9ct species (1 #bed4 ,repulsion ( electricities1 #bhc2 exp]im5ts det]m9+ ! laws ( electrical1 #bhf1 #bhg2 modes (1 9 /atic & 9 ,voltaic electricity1 #cag2 develop+ comets' tails1 #cge-cgg4 ,resi/ance1 a cause ( accel]at$ motion1 #cfg4 ,ret9a1 !1 action (1 9 receiv+ impressions1 #aff2 comp>ative s5sibility ( its fibres to light1 #agh4 ,retrograde motion ( comets1 #cei1 #cfh1 #cgc1 #cgi4 ,rhodiola rosea1 id5tical species (1 f\nd 9 ,t>t>y & 9 ,scotl&1 #bea4 ,rhomboh$rons ( c>bonate ( lime1 #aji4 ,ri*man1 ,pr(essor1 kill$ by lightn+1 #bic4 ,ri*t]1 v>iation 9 l5g? ( ! p5dulum obs]v$ by1 #ea4 ,r+s ( ,saturn1 #ff-fh2 ,saturn's1 diamagnetic1 #cdg2 lum9\s1 surr\nd+ comets1 #cgd1 #cge2 surr\nd+ ,donati's1 #cgi4 ,rit*ie1 ,pr(essor1 electrical exp]im5ts (1 #cad4 ,ritt]1 ,m41 *emical prop]ties ( ! sol> spectrum obs]v$ by1 #bjc2 oxydiz+ effect ( r$ rays1 #bji4 ,rive1 ,m4 ,augu/e de la1 rate ( increase ( temp]ature 9 wells obs]v$ by1 #bcj4 ,riv]s1 curvature ( ! l& prov$ by1 #df2 influ5ce (1 on ! e>?'s rotation1 #ga2 ris+ ( tides 91 #ih2 effect (1 9 cool+ ! atmosph]e1 #bdc4 ,roget1 ,dr41 ph5om5a ( electro-magnetism expla9$ by1 #cac4 ,rome1 obs]vations on lun> m\nta9s made at1 #gj2 era fix$ at1 #he2 comet discov]$ f1 #cgj4 ,ross1 ,sir ,james1 /ratum 9 ! ocean discov]$ by1 #aja2 depressure ( ! b>omet] obs]v$ by1 #abj2 volcanic region discov]$1 #bcb4 ,rosse1 ,"l1 nebul resolv$ by 8 telescope1 #djg1 #djh2 spiral nebula1 #dji1 #daj2 annul> nebul discov]$ by1 #daj2 nebul\s />1 #daa2 planet>y nebul1 #dab2 nebul resolv$ by1 #dae4 ,rotation affect+ w9ds1 #abb-abg2 ( w9ds1 #abd1 #abe2 ( hurricanes1 #abe1 #abf2 produc$ by ! ,voltaic curr5t act+ on iron1 #cje2 ( /ratifications ( electrical light1 #cjg2 caus$ by electricity1 #cac1 #cad2 ( light caus$ by an electric curr5t1 #cai2 ( magnets produc+ electricity1 #ccj-ccb2 *anges produc$ 9 comets by1 #cgf4 ,rotations ( ! sol> sy/em1 #g2 ( ! sun1 #fe2 ( ! planets1 #ff2 ( satellites1 #fh2 ( ,jupit]'s satellites1 #gj2 ( ! e>?1 a measure ( "t1 #ga2 influ5ce ( temp]ature on1 #gb2 axis (1 inv>iable1 #gf1 #gg4 ,rotatory motion1 =m indicat+1 #fe2 ( ,donati's comet1 #cgi4 ,r\x1 ,m4 le1 obs]vations on magnetic action 9 cry/als1 #cej4 ,rudb]g1 ,m41 refrangibility ( sub/ances asc]ta9$ by1 #bja1 #bjb4 ,ruhmkorff1 ,m41 improvem5ts on 8 electro-inductive app>atus1 #cbh4 ,russell1 ,scott1 ,mr41 velocity ( ! tidal wave e/imat$ by1 #ie4 ,russia1 arc ( ! m]idian measur$ 91 #dh2 climates (1 #bdd4 ,sab9e1 ,g5]al1 v>iations 9 ! magnetic elem5ts inve/igat$ by1 #cdc1 #cdd4 ,sagitt>ius1 comet trav]s+ ! con/ellation (1 #cgi2 ! ,milky ,way 91 #chf2 nebula1 #dad4 ,sah>a1 !1 caus+ monsoons1 #abd4 ---- des]t1 ext5t1 influ5ce (1 on ! atmosph]e1 #bdc4 ,salt1 ,mr41 papyrus s5t f ,egypt by1 #hi4 ,s&1 tubes 91 =m$ by lightn+1 #bic4 ,s&y des]ts influ5c+ temp]ature1 #bdc4 ,s&wi* ,l&1 excess ( cold 91 ov] correspond+ latitudes1 #bda4 ,s>gassa1 or grassy sea1 f\nd 9 ! ,atlantic1 #bec4 ,satellites1 int5sifi$ action ( attraction ^u1 #g2 intimate union (1 ) _! prim>ies1 #bf2 exceptions to a g5]al law ( ! sol> sy/em1 #fe1 note2 rotations equal to ! times ( _! revolutions1 #fh2 comet pass+ ?r\gh1 #fi4 ----1 ,jupit]'s1 proportion ( _! mass to t ( _! prim>y1 #bg2 di/urb+ =ce ( attraction affect+ _! orbits1 #bh2 p]iodic & secul> inequalities1 #bh1 #bi2 eclipses1 #cj2 rotation1 #gj2 passage ( a comet ?r\gh1 #cei2 comet ne>ly approa*+1 #cgj4 ---- ( ,saturn1 #cb2 ( ,uranus & ,neptune1 #cc4 ----1 mode ( comput+ _! masses1 #ee2 comp>ative d5sity (1 #eh4 ---- ( ,neptune1 #fc4 ---- ( ! e>?1 %oot+ />s1 #dbc4 ,saturn1 unequally occurr+ comp5sations ( di/urbance 9 its motions1 #ae2 di/urb+ influ5ce (1 on ,jupit]1 exc5tricity ( its orbit comp>$ ) ,jupit]'s1 #ag2 ret>d+ ! revolution ( ,jupit]'s nodes1 #ai2 inv>iable plane pass+ betwe5 ,jupit] &1 #bd2 obs]vations on ! mean motions ( ,jupit] &1 #be1 #bf2 eclipse (1 #db2 int]nal /ructure1 #eh2 a/ronomical tables (1 #fj2 p]iod ( 8 ye>1 #ff2 ! r+s (1 describ$1 #ff-fh2 8 r+ probably diamagnetic1 #cdg2 action (1 on ,halley's comet1 #cfb1 #cfc2 comets hav+ _! p]ihelia 9 8 orbit1 #cha4 ,saurian reptiles1 di/9ct tribes (1 #bed4 ,saussure1 ,m41 temp]ature ( m9es obs]v$ by1 #bbh1 #bbi2 li*5 discov]$ by1 #bdi4 ,sav>t1 ,m41 8 rese>*es & exp]im5ts 9 ac\/ics1 #acb1 #acc2 exp]im5ts on vibrations ( glass rul]s1 #ade-adg2 exp]im5ts %[+ sympa!tic undulations1 #adh1 #adi2 discov]ies on ! nature ( voice1 #aeb4 ,sav>y1 ,m41 orbital elem5ts ( a d\ble /> det]m9$ by1 #cif2 8 mode ( asc]ta9+ ! actual di/ances ( fix$ />s1 #djb1 #djc4 ,s*eele1 ,m41 *emical *anges effect$ by ! sol> spectrum obs]v$ by1 #bjc4 ,s*rot]1 height ( planet>y atmosph]es calculat$ by1 #bbf4 ,s*wabe1 ,m41 p]iodic v>iation 9 ! sol> spots obs]v$ by1 #cdd4 ,sci5ce1 its value reg>d$ z ! pursuit ( tru?1 #a2 errors ( ! s5ses correct$ by1 #cb2 evid5ce ( its antiquity1 #hg4 ,sci5ces1 mutual relations ( =ces prov+ ! connexion betwe51 #cai-cba2 analysis prov+ ! :ole circle (1 k91 #dbg1 #dbh4 ,scoresby1 ,capta91 ph5om5on occasion$ by refraction obs]v$ by1 #aef4 ,scorpio1 vacant pat* ( ! ,milky ,way 91 #chf2 position (1 #cij2 a d\ble /> 91 #cie2 nebula 91 #dad4 ,scotl&1 progress ( ! tidal wave r\nd1 #id4 ,sea1 !1 inappreciable influ5ce (1 on ! direction ( gravity1 #gg2 mean height ( sn[-l9e above ! level (1 #bda2 comp>ative ext5t (1 #bdb4 ,seasons1 conditions det]m9+ ! duration (1 #gd2 cause ( _! unequal p]iods1 #hg2 !ory ( ! tropical dry & ra9y1 #abc4 ,seawe$s1 photographic impressions (1 #bje1 #bjf2 luxuriance1 deep col\rs (1 #bec4 ,sec*i1 ,pr(essor1 m\nta9s ( ! moon obs]v$ by1 #gj2 photographic image ( ! moon obta9$1 #bad2 temp]atures ( ! sun's surface e/imat$1 #bbe2 exp]im5ts (1 9 photograph+ ! moon & ,jupit]1 #bbf1 #bbg4 ,secul> inequalities ( planets1 #ac1 #ad2 means ( discov]+1 #bd1 #be2 effect (1 on ! mean motion ( ! moon1 #cf1 #cg4 ---- v>iations 9 mean values ( ! magnetic elem5ts1 #cdc4 ,seebeck1 po9t ( maximum heat 9 sol> spectrum fix$ by1 #bfc2 discov]y (1 #bfd2 relations ( heat to electricity discov]$ by1 #ccb1 #ccc4 ,se$-lobes1 proportion 9 ! di/ribution ( plants hav+ "o or two1 #beb4 ,sel5iate ( z9c1 cry/als (1 #ajg4 ,s5>mont1 ,m41 exp]im5ts (1 9 expansion ( cry/als1 #bgc4 ,s5ses1 necess>ily inaccurate te/imony ( !1 #bha4 ,septemb]1 times co9cid+ 91 #hd4 ,s]p5t>ius1 /> 91 vani%+1 #cib4 ,%ell-fi%1 _! mode ( cl++ to rocks1 #aag4 ,%ield1 !1 clu/]s ( ! ,milky ,way betwe5 ,ophiu*us &1 #chg4 ,%oot+ />s1 ph5om5a (1 describ$1 #dba1 #dbb2 !ories (1 #dbc4 ,sib]ia1 ,ea/]n1 depression ( ! b>omet] obs]v$ 91 #abj4 ,sid]eal times1 mean1 p]iods (1 #hc2 measurem5t ( app>5t1 ib4 ,sigma ,eridani1 p]iod ( revolution 91 #djj4 ,silesia1 fulgorites f1 #bic4 ,silv] iodiz$1 its s5sitiv5ess to impressions1 #bba4 ,sirius1 ! ,egyptian ye> e/imat$ f1 #he2 comet's tail ext5d+ f ! ,h>e to1 #cgc2 rank (1 #chd2 comp>ative magnitude1 #che2 p>allax1 #chi2 cause ( 8 irregul> motion1 #cib2 *ange 9 col\r1 #dja2 light1 #djb2 ext5t ( surface1 #djd4 ,smy?1 ,admiral1 8 measurem5t ( ,etna comp>$ ) ,sir ,john ,h]s*el's1 #abj2 eclipse ( a d\ble /> obs]v$ by1 #cig2 its p]iodic "t det]m9$1 #cih4 ----1 ,piazzi1 heat ( ! moon felt by1 #bbg4 ,sn[1 cause ( p]petual1 on summits ( alp9e *a9s1 #aai2 causes modify+ ! height ( ! l9e ( p]petual1 #bda2 protect+ vegetation1 #bdi2 radiation ( heat by1 #beg4 ,soda1 sulphate (1 *ange ( =m 9 its cry/als1 #ajg2 cry/als ( ! neutral phosphate & ! ars5iate (1 #aji4 ,soil1 !1 dep5d5ce ( temp]ature on ! nature ( its products1 #bdc4 ,sol> gravitation1 #dbd1 #dbe4 ---- magnetism1 its connexion ) t]re/rial1 #cdd4 ---- spectrum1 cause ( ! po9t ( maximum heat v>y+ 91 #bfc1 #bfd4 ---- sy/em1 !1 gravitation ( ! bodies compos+1 #e2 conditions secur+ ! /ability (1 #aa1 #ab2 pro( ( its /ability1 #bj2 equilibrium (1 und]ang$ by ! e!real m$ium1 #bb2 inv>iable plane1 =m+ ! equator (1 #bc1 #bd2 "q ( its revolution r\nd a common c5tre1 #bd2 prop]ties ( its m$ium1 #cb2 masses ( bodies compos+1 #ee1 #ef2 _! diamet]s1 #ef2 uni=m direction ( rotation 91 #fe2 comp>ative app>5t importance (1 9 creation1 #bbf2 probably magnetic ?r\gh\t1 #cdf2 comets =m+ "p (1 #cfe2 possible ultimate de/ruction (1 #cgb2 computations ( comets revolv+ )91 #cha1 #chb2 pa?s describ$ by heav5ly bodies 91 #chb1 #chc2 position (1 relative to ! ,milky ,way1 #che2 direction ( its motion1 #dje4 ,soleil1 ,m41 cry/als compress$ by1 #ahi4 ,solids1 conditions r$uc+ molecul> p>ticles to1 #ajd1 #aje2 di/9ctive =ms tak5 by matt] 91 #ajf2 velocity ( s\nd pass+ ?r\gh1 #ace2 *ange ( %ape 91 accompany+ r++ s\nd1 #adg2 expansion (1 by heat1 #bga4 ,sol/ices1 !1 sol> motion at1 affect+ ! duration ( "t1 #hd2 ! ye> e/imat$ f ! w9t]1 #he2 p]iodical co9cid5ce ( ! sol> p]igee & apogee )1 #hf1 #hg4 ,so?aic p]iod1 !1 ( ! ,egyptians1 #he4 ,s\nd1 m$ium convey+1 #abi2 its propagation by undulations illu/rat$1 #abi1 #acj2 conditions modify+ ! int5sity (1 musical notes1 #aca2 exp]im5ts te/+ ! compass ( audible1 #acb1 #acc2 m$ia modify+ ! velocity (1 #acc-acg2 laws ( its reflection f surfaces1 #acg1 #ach2 undulations (1 subject to ! laws ( int]f]5ce1 #ach1 #aci2 laws ( ! f\ndation ( musical sci5ce1 #adj-adc2 re9=c$ by resonance ( cavities1 #aej1 #aea2 repeat$ vibrations requir$ to produce1 #agh2 diff]5t modes ( action 9 undulations produc+ light &1 #aii1 #bjj2 id5tical nature ( heat &1 #bhj1 #bha2 measur+ velocity1 #bij1 #bia4 ,s\nd+ bo>ds1 int5sify+ musical vibrations1 #adi2 action (1 9 musical in/rum5ts1 #aej4 ,s\?1 ,sir ,james1 positions ( /ell> sy/ems measur$ by1 #cif4 ,s\? pole1 !1 excess ( cold at1 #bda4 ---- ,sea isl&s1 height ( tides at1 #ih4 ,s\!rn ,ocean1 rise ( ! tidal wave 91 #ic2 velocity ( ! wave1 #id4 ,spa91 meteoric %[]s (f ! coa/ (1 #dba4 ,specific heat def9$1 #bge4 ,spectra ( gases & flames1 _! *>act]i/ic peculi>ities1 #afc1 #afd2 ?ree sup]pos$1 ( ! pure :ite sunbeam1 #bbb4 ,spectrum1 ! sol>1 decompos$ into sev5 col\rs1 #aei2 col\rs (1 modifi$ by ?ickness ( ! m$ium absorb+1 #afj2 decompos$ into ?ree col\rs1 #afa2 rayless l9es 91 #afb2 obs]vations & exp]im5ts on rayless l9es1 #afc1 #afd2 exp]im5t ( fluoresc5t light1 #aig2 obta9$ indep5d5tly ( prismatic refraction1 #bja2 en]getic action (1 on matt]1 #bjc2 photographic col\r$ images (1 #bjh-baj2 analysis1 prop]ties (1 exp]im5ts1 #baa-bai2 complex nature (1 #bbb2 produc$ f diffract$ light1 #bbc4 ---- ( an electric sp>k1 #bhi4 ---- ( ! ,voltaic arc1 #cjc4 ,sph]es1 mode ( attraction 9 holl[ & solid1 #d2 planets p>tak+ ! nature (1 #g2 impulses regulat+ rotations1 ib42 conditions procur+ ! figure (1 #dd2 =mula f9d+ ! d5sity1 #ef2 =ce giv+ ! =m (1 #ajf2 p[] ( reta9+ electricity1 #bhh4 ,sph]ical =m1 ! result ( cohesion1 #ajf4 ,sph]oids1 influ5c+ attraction diff]5tly f sph]es1 #d2 =ce di/urb+ attraction 91 #bg2 compression ( ! t]re/rial & ( ,jupit]'s1 comput$1 #ch1 #ci2 ( elliptical /rata1 quantities inv>iable 91 #df2 ( ! sun1 #fe2 effect produc$ by ! attraction ( an ext]nal body on1 #gi2 p[] ( reta9+ electricity1 #bhh4 ,spiral nebula1 #dji1 #daj4 ,spots on ! sun's surface1 p]iods ( _! vicissitudes1 #bbd2 am\nt ( heat v>y+ )1 #bbe4 ,spr+ tides1 #if-ii4 ,spr+s1 hot1 ris+ 9 m9es1 #bbi2 mean heat ( ! e>? det]m9$ f1 #bch4 ,/&>ds ( weights & measures1 :5ce d]iv$1 #hi1 #ij4 ,/>s1 fix$1 !1 ! sol> sy/em probably n indep5d5t (1 #bd2 velocity ( light d$uc$ f ab]ration (1 #ca2 va/ di/ances (1 #ed2 precession affect+ _! longitudes1 #hj2 computations ( _! positions furni%+ hi/orical data1 #hh1 #hi2 made visible by refraction1 #aed2 peculi> law ( light demon/rat$ by ! ab]ration (1 #bjb2 magnitude ( ! sol> sy/em se5 f1 #bbf2 numb]s1 classification (1 #chd2 positions1 #che2 ! ,milky ,way1 #che-chg2 p>allaxes & di/ances (1 #chg-chi2 v>iable1 #cij-cie2 miss+1 #cie2 sy/ems ( multiple1 classifi$1 ib42 b9>y1 #cie-djf 7see ,d\ble />s72 nebul\s1 #djf-dai 7see ,nebul72 seem+ly innum]able1 #dbj2 meteors1 #dbj-dbc4 ,/atic electricity1 #bhb3 see ,electricity4 ,/eam1 =mation (1 #bfi2 =ce conv]t+ liquids into1 #bgg2 measure ( its ela/icity1 #bgh2 "q ( its be+ sup]s$$ by electricity1 #cbh4 ,/eel1 p>amagnetism induc$ 91 #ccf2 conditions ( magnetic p[] rema9+ p]man5tly 91 #ccg1 #cch2 its ela/icity affect$ by magnetism1 #ceb4 ,/eph5son1 ,george1 quotation f1 #bgi-bhj4 ,/okes1 ,pr(essor1 rem>ks (1 on gradation ( col\rs1 #afa2 exp]im5ts on fluoresc5ce ( light1 #aig2 8 decision ) reg>d to vibrations ( pol>is$ light1 #bbc4 ,/orms1 magnetic1 #cdd2 v>y+ ) latitude1 #cde1 #cdf4 ,/rata ( ! e>?1 position & comp>ative d5sity (1 #gg4 ,/ratifications1 exp]im5ts %[+1 9 electric light1 #cjf1 #cjg4 ,/ruve1 ,m41 measurem5t by1 #dh2 8 obs]vations on ,saturn's r+s1 #fh2 occultation by a comet obs]v$ by1 #cfd2 comet's nucleus describ$1 ib42 di/ance ( a fix$ /> measur$ by1 #chh1 #chi2 catalogue ( d\ble />s1 #cif2 rem>ks on col\r & light ( d\ble />s1 #dja2 sun's motion prov$ by1 #dje4 ,/utg>dt1 natural hot spr+s us$ 9 manufactories ne>1 #bca4 ,subm>9e telegraph1 #cbe-cbg4 ,sulphate ( magnesia1 its cry/als boil$ 9 alcohol1 #ajh4 ---- ( nickel1 effect ( exposure to ! sun1 on its cry/als1 #ajg4 ---- ( soda1 its cry/als1 #ajg4 ---- ( z9c1 exp]im5t on its cry/als1 #ajh4 ,sulphurett$ hydrog5 gas1 its con/itu5t p>ts1 #aaa4 ,sumbawa1 volcanic eruption (1 #bcc4 ,summ]1 mean temp]ature (1 v>y+ 9 ! same latitude1 #bdf1 #bdg2 atmosph]ic electricity 91 #bia4 ,sun1 !1 law regulat+ 8 attraction ( heav5ly bodies1 #e2 effect ( 8 attraction on planet>y orbits1 mean di/ance ( planets f1 #h2 importance ( 8 magnitude 9 ! sol> sy/em1 #ab2 di/urbances 9 ! relative positions ( planets &1 #ad2 =ce modify+ 8 int5sity ( attraction1 #af2 resi/ance (f]$ by1 to ! p[] ( di/urb+ =ces1 #bj2 p]iods ( conjunctions ( ,jupit]1 ,saturn1 &1 #be2 influ5ce (1 on lun> motions1 #cd1 #ce2 action ( ! planets reflect$ by1 #cg2 eclipses (1 #dj1 #da2 suppos$ con/itution (1 #da2 8 atmosph]e1 #db2 mode ( f9d+ 8 p>allax1 #eb1 #ec2 mean di/ance f ! e>?1 #ec2 mass (1 #ee2 diamet]1 #ef2 comp>ative d5sity1 attractive =ce1 #ef1 #eg2 a/ronomical tables (1 #fc2 d$uctions f 8 rotation ab\t an axis1 p]iod (1 #fe2 attraction (1 produc+ a precession ( ! equ9oxes1 #gi1 #ha2 returns (1 a measure ( "t1 #hc-he2 divisions ( "t1 dep5d5t on revolutions ( ! major axis ( 8 orbit1 #hf1 #hg2 action on tides1 #ib1 #ig2 di/urb+ ! equilibrium ( ! atmosph]e1 #aba2 dry & ra9y seasons regulat$ by1 #abc2 cause ( decreas$ light & heat 9 horizontal rays1 #aeg1 #aeh2 di/ance (1 falsely e/imat$1 #aeh2 light pol>iz$ by1 #aie2 indications ( an absorptive atmosph]e surr\nd+1 #bab1 #bac2 8 diamet]1 #bbd2 appe>ance (1 ?r\gh 8 atmosph]es1 ib42 v>iations 9 heat & light emitt$ f1 #bbe1 #bbf2 am\nt ( heat annually receiv$ by ! e>? f1 #bch2 effect ( 8 brilliancy on ! heat emitt$ by1 #bei2 8 position affect+ v>iations 9 ! magnetic elem5ts1 #cdc1 #cdd2 connexion betwe5 p]iodic v>iation 9 8 spots & 9 ! magnetic elem5ts1 #cdd2 va/ sweep ( 8 gravitat+ =ce1 #cfe2 increas$ attraction (1 = comets1 #cgb2 gulfs sep>at+ />s f1 #cij2 possibility ( *ange 9 8 lu/re1 #cid2 spot on1 measur$ by ,sir ,john ,h]s*el1 #cid1 #cie2 proportion ( 8 light to ! moon's1 #djd2 rate & orbit ( motion ) 8 sy/em1 #dje1 #djf2 a nebul\s />1 #dab2 meteoric nebula revolv+ r\nd1 #dbb2 gravitat+ =ce (1 #dbd1 #dbe4 ,sunbeams1 resolv$ into _! compon5t col\rs1 #aei-afb2 law prevail+ 9 ! ph5om5a (1 #aih2 light a di/9ct prop]ty (1 #bad2 resolv$ into ?ree spectra1 #bbb2 undulations con/itut+1 #bbc2 _! influ5ce on vegetation1 #bdi4 ,swan1 !1 vani%+ /> 91 #cic4 ,switz]l&1 meteors fall+ 91 #dba4 ,sy5e1 arc ( ! m]idian measur$ betwe5 ,alex&ria &1 #di4 ,sykes1 ,colonel1 ext5sive range ( cultivation ( :eat obs]v$ by1 #bej4 ,sympa!tic vibrations 9 musical in/rum5ts1 #adg-adi4 ,syr51 !1 an in/rum5t asc]ta9+ ! numb] ( musical pulsations 9 a second1 #adc4 ,syzygies1 tides increas$ 9 !1 #if4 ,table-l&s1 high1 influ5ce (1 on ! atmosph]e1 #bda4 ,tahiti1 transit ( ,v5us obs]v$ at1 #ec4 ,tail ( comets1 sudd5 developm5t (1 #cgb2 =ces produc+1 #cge2 unequal illum9ation (1 #cge1 #cgf2 *ange 9 position (1 #cgf2 divid$1 ib42 con/itution (1 #cgg4 ,talbot1 ,fox1 8 inv5tions 9 photography1 #bjd4 ,tang5t1 a1 to planet>y orbits1 planets impell$ 9 ! direction (1 #h2 =ce1 di/urb+1 9 ! direction (1 #ad1 #ae2 deflection f1 a measurem5t ( c5trifugal =ce1 #di4 ,tang5tial =ce1 occasion+ secul> inequalities1 #ad2 effects produc$ by1 #ae2 produc+ ! v>iation ( ! moon1 #ce2 =ce act+ on ! sea1 #ajj4 ---- velocity1 effects produc$ by modifications (1 #af2 undim9i%$ by ! e!real m$ium1 #bb4 ,telegraph1 ! electric1 discov]y lead+ to ! inv5tion (1 #cbc1 #cbd2 ! ,atlantic1 #cbe2 pr9ciples ( its con/ruction1 #cbf1 #cbg2 date ( its completion1 #cbg4 ,telegraphs1 l&1 pr9ciple ( _! con/ruction1 #cbh4 ,telescope1 ! a*romatic1 pr9ciple ( its con/ruction1 #afd4 ----1 ! diff]5tial1 diff]5ces 9 illum9ation det]m9$ by1 #bbg4 ----1 ,"l ,rosse's1 nebul resolv$ by1 #djg1 #dae4 ,telescopium1 comet trav]s+ ! con/ellation (1 #cgi2 nebula 91 #dad4 ,temp]ature1 a decrease 91 affect+ ! e>?'s rotation1 #gb2 exc5tricity ( ! t]re/rial orbit1 a cause ( decreas+1 #gc2 law equalis+1 #gd2 geological *anges affect+1 #ge4 ----1 v>y+ 9 ! t]re/rial atmosph]e1 zone ( con/ant1 #aai2 affect+ atmosph]ic undulations1 #aba2 modify+ ! velocity ( s\nd1 #acd2 *emical action ( light affect$ by1 #bah-bbb2 ( ! e!real m$ium1 #bbg1 #bbh2 und]gr\nd /ratum ( con/ant1 #bbh2 rate ( increase 91 bel[ ! e>?'s cru/1 #bbh1 #bca2 ( ! ocean1 #bca2 mode ( f9d+ annual av]age1 #bci2 causes ( di/urbance 9 regul> v>iation (1 #bdj-bde2 v>iations 9 ! same latitude1 #bdf1 #bdg2 influ5ce (1 on vegetation1 #bdh2 affect+ transmission ( heat1 #bei1 #bfj2 ( solid bodies1 caus$ by absorption ( rays1 #bfh2 affect+ ! l5g? ( ! p5dulum1 #bgb2 causes ( p]petual v>iations 91 #bgd2 transmission ( electricity affect$ by1 #bhd2 affect+ magnetism1 #ceb4 ,t5]iffe1 ! ,peak (1 prevail+ w9ds on1 #abd2 lun> heat on1 #bbg2 zones ( vegetation1 #bej2 "* ( its flora1 #beb4 ,t]re/rial globe1 !1 a magnet1 #ccf4 ---- magnetism1 #cda-cdc2 ! ?ree elem5ts & _! v>iations1 #cdc1 #cdd2 /orms1 p]iod ( _! v>iation1 #cdd2 its connexion ) sol> magnetism1 ib42 effect ( atmosph]ic magnetism on1 #cde2 probable cause (1 #cdf2 effect ( planet>y magnetism on1 #cdf1 #cdg4 ---- m]idian1 a1 def9$1 #df4 ,tessul> sy/em ( cry/allization1 #ajh4 ,texas1 monsoons occasion$ by its des]ts1 #abd4 ,?ames1 !1 p]iod occupi$ by ! tidal wave 9 rea*+1 #id4 ,?aw1 cause ( ! s5sible *ill9ess (1 #bgf4 ,!ory ( probabilities1 use (1 9 det]m9+ a/ronomical data1 #fj4 ,!rmo-electric curr5ts1 discov]y (1 #ccb2 ph5om5a exhibit$ by1 #ccc2 pr9ciple (1 appli$ to measur+ heat1 #ccc1 #ccd4 ,!rmography1 examples (1 #bai-bba4 ,!rmomet]1 !1 pr9ciples appli$ to ! con/ruction (1 #aac2 consult$ 9 det]m9+ m\nta9 heights1 #aai1 #abj2 refraction v>y+ )1 #aed2 heat measur$ by motion 91 #bgd4 ,!rmomultipli]1 use (1 9 exp]im5ts1 #bfd2 pr9ciple ( its con/ruction1 #ccc1 #ccd4 ,!ta ,orionis1 ! multiple sy/em (1 #cie4 ,?omas1 ,/41 ! isl& (1 hurricane ) pauses at1 #abg4 ,?omson1 ,w41 ,pr(essor1 exp]im5ts (1 9 freez+ wat]1 #bga2 dynamical !ory ( heat ma9ta9$ by1 #bge note2 8 calculation ( ! =ce ex]t$ 9 vibrations ( light1 #bgi2 inve/igation into ! relations ( light & magnetism1 #cbj2 d5sity ( ! e!real m$ium comput$ by1 #cef2 magnetic prop]ty ( ! e!real m$ium plead$ =1 #ceg4 ,?und]1 !ory ( prolong$ peals (1 #ach4 ,tibet1 :eat rip5+ 91 #bej4 ,tidal wave1 !ory (1 #ib2 its bir?place1 #ic2 c\rse (1 #ic1 #id2 velocity1 #id2 effect ( dep? on its motion1 #ie4 ,tides1 calculation f ! moon's action on1 #ee2 !ory ( =ces produc+1 #ia1 #ib2 circum/ances occasion+ irregul>ities1 #ic2 ris+1 progress (1 #ic1 #id2 ?ree k9ds ( oscillations 91 #ie1 #if2 v>iations 91 f lun> & sol> influ5ce1 #if-ih2 effect ( int]f]5ce ( waves on1 #ii2 ! sea's equilibrium und]ang$ by1 #ajj4 ----1 lun> & diurnal1 ( ! t]re/rial atmosph]e1 #aba2 examples ( sympa!tic undulation1 #adh4 ,"t1 a measure ( motion1 #eh2 a measure ( angul> motion1 #hc2 diff]5ce betwe5 mean & app>5t sol>1 #hd2 mean equ9octial1 mode ( comput+ its object1 #hf2 e/imation (1 correct$ by means ( laws ( unequal expansion1 #bgb4 ,timo*>is1 comp>ison ( 8 obs]vations ) ,hipp>*us1 #hj4 ,tomboro1 subm]g$ 9 a volcanic eruption1 #bcc4 ,toronto1 obs]vations on magnetic /orms at1 #cdf4 ,torp$o1 !1 electrical action (1 #caj1 #caa4 ,torricellian vacuum1 exp]im5t on ! electric dis*>ge 9 !1 #cjf2 l9es ( magnetic =ce pass+ ?r\gh1 #cdd4 ,t\can1 comet approa*+ ! con/ellation (1 #cgi2 a nebula 91 #dad4 ,t\cani1 #dg2 globul> nebul\s clu/]1 #dad4 ,t\rmal9e1 br[n1 light pol>iz$ by prisms (1 #ahj2 prop]ty qualify+ x to analyze pol>iz$ light1 #ahb2 col\r$ images produc$ by1 #ahf1 #ahg2 *ang$ by compression1 #ahi2 heat pol>iz$ by1 #bfe2 electricity communicat$ to1 #bhd4 ,trade w9ds1 friction (1 n affect+ ! e>?'s velocity1 #gb2 action on ! g5]al motion ( ! sea1 #ajj2 sy/em (1 acc\nt+ = atmosph]ic anomalies1 #abj2 !ory ( _! orig91 ph5om5a connect$ )1 #abb1 #abc2 becom+ monsoons1 #abd4 ,transits ( ,v5us1 #eb1 #ec4 ----1 two consecutive1 ( any />1 a measure ( "t1 #hc4 ,transmission ( radiant heat1 #beh1 #bfb2 ( electricity1 #bhd1 #bhe2 ( voltaic electricity1 #bih2 molecul> /ructure affect+1 #cjc2 me?od (1 det]m9+ ! influ5ce ( electric curr5ts1 #cag2 ( gravity1 an unsolv$ "q1 #cee2 probable ag5t1 #cef2 m$ium (1 9 space1 #dbd4 ,transp>5t bodies1 temp]ature (1 unaffect$ by ! sun's rays1 #bbg4 ,trees1 numb] ( species ( =e/1 f\nd 9 ,am]ica & ,europe1 #beb4 ,tribes1 app>5tly di/9ct1 ( ! human race1 #bee4 ,triple />s1 #cie2 p]iods ( revolution 91 #djj4 ,tropical ye>1 *ange 9 its l5g?1 #hj2 p]iod (1 #hc2 difficulty ( adju/+ its e/imation1 #he4 ---- revolution ( ! major axis ( ! sol> ellipse1 its p]iod1 #hf4 ---- vegetation1 ! luxuriance (1 #bdh4 ,tuil]ies1 clock 9 !1 %[+ decimal "t1 #hd4 ,twilight1 caus$ by refraction1 #aed2 effect ( reflection1 #aeh4 ,tyndall1 ,pr(essor1 8 exp]im5ts prov+ diamagnetic pol>ity1 #cdh2 on magnetic action 9 cry/als1 #cdi4 ,undulations1 !ory (1 #ii2 ( ! atmosph]e1 #aba1 #abb2 ( ! waves ( s\nd1 #abi1 #acj2 int]vals produc$ by int]f]5ce1 #aci2 giv+ musical notes1 #adb1 #adc2 sympa!tic1 #adg1 #adi2 ( ! lum9\s e!r1 #afi1 #agj2 9 refraction & reflection1 #agg2 produc+ fluoresc5ce1 #aig2 diff]5t1 9 light & s\nd1 #aii1 #bjj2 con/itut+ a sunbeam1 #bbc2 heat propagat$ by1 #bfg2 ( light1 evolution ( lat5t =ce 9 ext+ui%$1 #bgi1 #bhj2 ( natural =ces id5tical1 #bha4 ,undulatory !ory ( light1 #afh-agj2 law ( motion affect+1 #agf1 #agg2 ph5om5a prov+1 #aih2 objection1 f ! diff]5t action ( light & s\nd1 refut$1 #aii2 prov+ ! exi/5ce ( ! e!real m$ium1 #ceh2 accel]ation 9 comet's motion prov+1 #cfg4 ---- !ory1 exp]im5ts det]m9+ 9 fav\r (1 #bjj1 #bja2 f9al & decisive exp]im5t1 #bjb2 ( heat1 #bfg4 ,unison1 note 91 #adb4 ,unit$ ,/ates1 a/ronomical obs]vations made 91 #cga1 #cgc4 ,uranium1 phosphoresc5t prop]ty (1 #bif2 peculi> lum9\s prop]ties (1 #bif4 ,uranus1 effect ( reciprocal attraction betwe5 ,neptune &1 #bb2 p]iods ( ! revolutions ( 8 satellites1 #cc2 di/ance f ! sun1 #ed2 a/ronomical tables (1 #fj2 discov]y sugge/$ by 8 p]turbations1 #fa2 obs]vations on1 lead+ to ,neptune's discov]y1 #fb2 sun's influ5ce 91 #bbe2 action (1 on ,halley's comet1 #cfc2 appe>ance ( ! sun to1 #chj1 #cha2 comets 9 8 orbit1 #cha1 #chb4 ,ursa ,major1 p]iodic "t ( a d\ble /> 91 #cih2 nebul\s region (1 #dag4 ,utah1 des]ts (1 caus+ monsoons1 #abd4 ,vacuum produc$ by %ell-fi%1 #aag2 exi/+ 9 ! air1 #aah4 ,valz1 ,m41 telescopic planet discov]$ by1 #ba2 comet obs]v$ by1 #ceh2 obs]vations on a comet's approa* to ! sun1 #cfd2 cause assign$ by1 = contraction 9 diamet] ( comets1 #cgg1 #cgh4 ,vap\r1 =mation & disp]sion (1 #bfi1 #bgj2 =ce develop+1 #bgg4 ,v>iable />s1 p]iodic fluctuation ( lu/re 91 #cij1 #cia2 new1 appe>+ & vani%+1 #cib1 #cid2 miss+1 #cie4 ,v>iables1 region ( !1 #abb4 ,vegetation1 effect (1 9 l[]+ temp]ature1 #bdc2 ! two requisites =1 #bdh2 /r5g? & vitality (1 #bdi2 *emical action ( light influ5c+1 ib42 laws ( its di/ribution1 #bdi-beb2 di/ribution ( m>9e1 #beb1 #bec2 !ories ( specific div]sity ( orig9al di/ribution (1 #bec1 #bed4 ,v5us1 zone ( in/ability betwe5 ! sun &1 #ba2 p]turbation 9 ! mean motion ( ! e>? &1 #bf2 eclips+ ,m]cury1 #db2 transits (1 p>allaxes calculat$ f1 #eb1 #ec2 a/ronomical tables (1 #fc2 climate1 #bbf4 ,v]nal equ9ox1 planet>y motions e/imat$ f1 #i4 ,ve/a1 a/ronomical tables (1 #fc2 no atmosph]e surr\nd+1 #bbf4 ,vesuvius1 reviv$ volcanic action (1 #bcd4 ,vibrat+ plates us$ 9 exp]im5ts on musical s\nd1 #add1 #adg4 ,vibrations ( ! air produc+ s\nd1 #abi2 9 music1 #aca2 numb] made by ! human voice 9 a second1 #acb4 ---- ( ! e!r 9 natural & pol>iz$ light1 #aic2 9 fluoresc5ce ( light1 #aif2 plane (1 9 pol>iz$ light1 #bbc4 ,vico1 ,padre de1 comet discov]$ by1 #cgj4 ,vi5na1 obs]vations on comets f1 #cgj4 ,viet*1 ,james1 comet ) lum9\s r+s discov]$ by1 #cgd1 #cge4 ,v9c5t1 ,/41 revival ( an ext9ct volcano 91 #bcd4 ,virg9ia1 dagu]reotyp$ spectral image obta9$ 91 #bac4 ,virgo1 planet>y conjunction betwe5 ,libra &1 #db2 v>iable /> 91 #cib2 /> vani%$ f1 #cie2 nebul\s zone pass+1 #daf1 #dag4 ,vivi]s1 transit ( a comet across ! sun obs]v$ f1 #cgd4 ,volcanic regions ( ! globe1 #bcb2 annual numb] ( eruptions1 #bcc2 celebrat$ eruptions1 ib42 e>?quakes caus$ by1 #bcd2 suppos$ causes ( action1 #bce2 ,sir ,john ,h]s*el's !ory1 #bce-bcg4 ,volta1 ,pr(essor1 electricity r5d]$ manageable by1 #big2 ! _w's debt to1 #cbh4 ,voltaic electricity1 fir/ sugge/ions (1 #big2 !ory ( ! transmission (1 #bih2 con/ruction ( ! batt]y1 #bih1 #bii2 !ory ( its production1 #cjj2 *>act]i/ic prop]ties1 #cjj1 #cja2 action (1 g5]at+ heat & light1 #cja-cjc2 arc1 exp]im5ts1 #cjc-cje2 !1 dis*>ge oxidiz+ silv]1 #cje1 #cjf2 /ratifi$ light1 #cjf1 #cjg2 *emical decomposition effect$ by ag5cy (1 #cjg1 #cjh2 cry/allization1 #cjh2 an ag5t 9 ! f9e arts1 #cji2 conductors (1 ib42 relations ( heat &1 #caj2 fi% produc+ effects (1 #caj1 #caa2 sci5ce sugge/$ by its influ5ce on a magnetiz$ ne$le1 #cab2 rotation effect$ by1 #cac1 #cad2 induc+ magnetism1 #cad1 #cae2 di/9ction betwe5 /atic electricity &1 #cag2 unv>y+ dual =ce (1 #ccd4 ,voltaic pile1 !1 inv5tion (1 #big2 p]fect$1 #bih-cjj4 ,vortices1 molecul>1 !ory (1 #ajd4 ,vosges m\nta9s1 temp]ature ( m9es 9 !1 #bbh4 ,vulpecula1 nebula 91 #dji4 ,w>dhus1 transit ( ,v5us obs]v$ at1 #ec4 ,wat*es1 irregul> action (1 correct$ by ! laws ( unequal expansion1 #bgb4 ,wat]1 con/itu5t p>ts (1 #aaa2 boil+ po9t (1 an e/imate ( m\nta9 heights1 #abj2 z a m$ium = s\nd1 #ace2 light pol>iz$ circul>ly by1 #aid2 exp]im5t decid+ ! velocity ( light 91 #bjb2 law ( expansion (1 #bga2 process ( congelation1 #bgf2 boil+ po9ts (1 #bgg2 decompos$ by electric ag5cy1 #cjg2 z an electric conductor1 #cji2 rotat+ by electricity1 #cad4 ,wat]sp\ts1 orig9 & cause (1 #abh4 ,wat]/one1 ,mr41 magnetic prop]ty ( ! e!real m$ium ma9ta9$ by1 #ceg4 ,waves neutraliz$ by int]f]5ce1 #ii4 ----1 atmosph]ic1 ov] local di/ricts1 p]iods1 dim5sions (1 #aba1 #abb4 ---- ( s\nd1 #aca2 furni%+ an illu/ration ( reflections ( s\nd & light1 #acg2 int]f]5ce (1 produc+ calm1 #aci4 ,w$gwood1 ,dr41 attempts (1 to trace objects by means ( light1 #bjc1 #bjd4 ,week1 !1 ( sev5 days1 ! mo/ anci5t & univ]sal division ( "t1 #he4 ,wells1 increase ( temp]ature 91 #bcj1 #bca4 ,wel%1 ,mr41 obs]vations made by1 9 a balloon asc5t1 #aai4 ,we/ ,indies1 !1 cause ( hurricanes 91 #abf4 ,:eels inv5t$ to te/ int5sity ( s\nd1 #acb1 #acc4 ,:eat1 range ( its cultivation1 #bej4 ,:eat/one1 ,pr(essor1 exp]im5ts 9 ac\/ics (1 #acb2 musical in/rum5ts inv5t$ by1 #adc2 pap] on musical vibrations read by1 #ade2 exp]im5ts on s\nd+ bo>ds (1 #aej2 exp]im5ts on s\nd re9=c$ by resonance1 #aea2 in/rum5t measur+ velocities ( electricity & light inv5t$ by1 #bjb2 spectrum ( an electric sp>k obs]v$1 #bhi2 spe$ ( electricity measur$1 #bhi1 #bij2 exp]im5ts on ! spectrum ( ,voltaic flame1 #cjc4 ,willis1 ,mr41 articulat+ ma*9e inv5t$ by1 #aea2 inve/igations (1 into ! me*anism ( ! l>ynx1 #aeb4 ,w9ds1 trade1 #abb1 #abc2 monsoons1 #abd2 extra-tropical1 9 ! ,nor? ,atlantic1 ib42 curr5ts above ! trade w9ds1 #abd1 #abe2 ph5om5a ( rotatory motion1 #abe2 hurricanes1 #abe1 #abh2 ag5cy (1 influ5c+ temp]ature1 #bdd1 #bde4 ,w9es1 range ( cultivation ( ! be/1 #bej4 ,w9t]1 atmosph]ic electricity 91 #bia4 ----1 mean temp]ature (1 v>y+ 9 ! same latitude1 #bdf1 #bdg4 ,wolf1 ,pr(essor1 p]iods ( v>iation 9 sol> heat comput$ by1 #bbe4 ,wolla/on1 ,dr41 exp]im5ts (1 on s5sitiv5ess to s\nd1 quotation f1 #acb2 exp]im5t (1 to %[ ! effect ( v>iable m$ia on refraction1 #aef2 discov]y ( rayless l9es 9 ! sol> spectrum1 #afb2 obs]vations (1 on ! *emical prop]ties ( ! sol> spectrum1 #bjc1 #bji2 magnetic rotation sugge/$ by1 #cac2 light emitt$ by ! heav5ly bodies calculat$1 #djd4 ,xi ,urs ,majoris1 p]iodic "t (1 #cih2 velocity ( ! revolv+ />1 #djj4 ,ye>1 a1 9 ,jupit] & ,saturn1 #ff2 tropical *ange 9 its l5g?1 #hj2 l5g? ( ! sid]eal1 ib42 p]iod ( ! mean1 #hc2 e/imation ( ! ,egyptian1 #he2 fir/ ( our era1 #hf2 l5g? 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