file :i* includes ! orig9al illu/rations4 ,see #cffia-;h4htm or #cffia-;h4zip3 7https3_/_/www4gut5b]g4org_/ca*e_/epub_/ #cffia_/pg#cffia-;images4html7 or 7https3_/_/www4gut5b]g4org_/files_/#cffi a_/cffia-;h4zip7 ,,conv]sations ,,on ,,natural ,,philosophy1 ,,9 ,,:i* ,,! ,,elem5ts ,,( ,,t ,,sci5ce ,,are ,,famili>ly ,,expla9$4 ,illu/rat$ ) ,plates4 ,,by ,,! ,,au?or ,,( ,,conv]sations ,,on ,,*emi/ry1 c4 ,,) ,,corrections1 ,,improvem5ts1 ,,& ,,consid]able ,,additions ,,9 ,,! ,,body ,,( ,,! ,,"w2 ,appropriate ,que/ions1 & a ,gloss>y3 ,,by ,,dr4 ,,?omas ,p4 ,,jones1 ,,pr(essor ,,( ,,me*anics1 ,,9 ,,! ,,frankl9 ,,in/itute ,,( ,,! ,,/ate ,,( ,,p5nsylvania4 ,philadelphia3 ,publi%$ & ,sold by ,john ,grigg1 ,no4 #i ,nor? ,f\r? ,/reet4 ,/]eotyp$ by ,l4 ,johnson4 #ahbf4 ,ea/]n ,di/rict ( ,p5nsylvania1 to wit3 ,be x rememb]$1 t1 on ! tw5ty-f\r? day ( ,april1 9 ! ,fiftie? ye> ( ! ,indep5d5ce ( ! ,unit$ ,/ates ( ,am]ica1 ,a4 ,d4 #ahbf1 ,john ,grigg1 ( ! said ,di/rict1 ha? deposit$ 9 ?is (fice ! title ( a book1 ! "r :]e( he claims z proprietor1 9 ! words foll[+1 to wit3 ,conv]sations on ,natural ,philosophy1 9 :i* ! ,elem5ts ( t ,sci5ce are famili>ly expla9$4 ,illu/rat$ ) ,plates4 ,by ! ,au?or ( ,conv]sations on ,*emi/ry1 c4 ,) ,corrections1 ,improvem5ts1 & consid]able ,additions1 9 ! ,body ( ! ,"w2 appropriate ,que/ions1 & a ,gloss>y3 ,by ,dr4 ,?omas ,p4 ,jones1 ,pr(essor ( ,me*anics1 9 ! ,frankl9 ,in/itute1 ( ! ,/ate ( ,p5nsylvania4 ,9 con=mity to ! ,act ( ! ,congress ( ! ,unit$ ,/ates1 entitl$ ,an ,act = ! ,enc\ragem5t ( ,le>n+1 by secur+ ! ,copies ( ,maps1 ,*>ts1 & ,books1 to ! ,au?ors & ,proprietors ( su* ,copies1 dur+ ! times !re9 m5tion$2--,& also to ! ,act1 entitl$1 ,an ,act supplem5t>y to an ,act1 entitl$1 ',an ,act = ! ,enc\ragem5t ( ,le>n+1 by secur+ ! ,copies ( ,maps1 ,*>ts1 & ,books1 to ! ,au?ors & ,proprietors ( su* ,copies dur+ ! times !re9 m5tion$1' & ext5d+ ! b5efits !re( to ! arts ( design+1 engrav+1 & et*+1 hi/orical & o!r pr9ts4 ,d4 ,,caldwell1 ,cl]k ( ! ,ea/]n ,di/rict ( ,p5nsylvania4 ,,preface4 ,not)/&+ ! great numb] ( books :i* are writt51 expressly = ! use ( s*ools1 & :i* embrace e subject on :i* in/ruction is giv51 x is a lam5table fact1 t ! catalogue ( ^? :i* are well adapt$ to ! int5d$ purpose1 is a v %ort "o4 ,almo/ all ( !m h be5 writt51 ei!r by ^? :o are )\t exp]i5ce z tea*]s1 or by tea*]s1 defici5t 9 a compet5t k ( ! subjects1 on :i* !y treat4 ,e intellig5t p]son1 :o has devot$ himself to ! in/ruction ( y\?1 mu/ h felt & deplor$1 ! tru? ( ^! obs]vations4 ,9 mo/ in/ances1 ! improvem5t ( a "w already 9 use1 w be m acceptable1 ?an "o ( equal m]it w\ld be1 :i* is entirely new2 ! introduction ( a book into s*ools1 be+ always att5d$ ) "s difficulty4 ,! ,conv]sations on ,*emi/ry1 writt5 by ,mrs4 ,m>cet1 _h obta9$ a well-m]it$ celebrity1 & 0 v ext5sively adopt$ z a s*ool-book1 be=e ! publication ( h] ,conv]sations on ,natural ,philosophy4 ,?is1 also1 has be5 mu* us$ = ! same purpose2 b1 ! obs]vation has be5 v g5]al1 among intellig5t tea*]s1 t1 9 its execution1 x is v inf]ior to ! =m] "w4 ,! editor ( ! edition n[ pres5t$ to ! public1 _h und]tak5 to add to ! "w1 que/ions1 = ! exam9ation ( le>n]s2 & notes1 :]e he deem$ !m necess>y4 ,he soon f\nd1 h[ev]1 t ! latt] und]tak+ w\ld be a v unpleasant "o1 z he mu/ h po9t$ out at ! bottom ( _m ( ! pages1 ! defects & mi/akes 9 ! text2 :il/ num]\s modes ( illu/ration1 or =ms ( expression1 :i* 8 exp]i5ce z a tea*]1 _h conv9c$ him w\ld n be cle> to ! le>n]1 mu/1 ( necessity1 h rema9$ unalt]$4 ,he !re=e det]m9$ to revise ! :ole "w1 & ) ! mo/ p]fect fre$om1 to make su* alt]ations 9 ! body ( x1 z %\ld1 9 8 op9ion1 be/ adapt x to ! purpose = :i* x 0 design$4 ,7 ! book1 z x n[ /&s1 c>efully comp>$ ) ! orig9al1 x w\ld be f\nd1 t1 9 con=mity ) ?is det]m9ation1 sc>cely a page ( ! latt]1 rema9s un*ang$4 ,v]bal alt]ations h be5 made1 errors1 9 po9ts ( fact1 h be5 correct$2 & new modes ( illu/ration h be5 introduc$1 :5ev] x 0 ?\ght t ^? already employ$1 c\ld be improv$2 or :5 x 0 kn[n1 t1 f local causes1 !y are n famili>1 9 ?is c\ntry4 ,! editor feels assur$1 t1 9 p]=m+ ?is task1 he has r5d]$ ! book m valuable to ! tea*]1 & m useful to ! pupil2 & he d\bts n t ! intellig5t au?or ( x1 w\ld pref] ! mode :i* has be5 adopt$1 to t :i* 0 at fir/ propos$4 ,! judici\s tea*] w1 ( c\rse1 v>y ! que/ions accord+ to circum/ances2 & ^? :o may n employ !m at all1 z que/ions1 w /ill f9d !m useful1 9 direct+ ! pupil to ! mo/ important po9ts1 9 e page4 ,! ,gloss>y has be5 conf9$ to su* t]ms ( sci5ce z occur 9 ! "w2 & is believ$ to include all ^?1 ( :i* a cle> def9ition _c be f\nd 9 our common diction>ies4 ,,cont5ts4 ,,conv]sation ,i4 ,,on ,,g5]al ,,prop]ties ,,( ,,bodies4 #i ,,introduction4 ,g5]al ,prop]ties ( ,bodies4 ,imp5etrability4 ,ext5sion4 ,figure4 ,divisibility4 ,in]tia4 ,attraction4 ,attraction ( ,cohesion4 ,d5sity4 ,r>ity4 ,heat4 ,attraction ( ,gravitation4 ,,conv]sation ,,ii4 ,,on ,,! ,,attraction ,,( ,,gravity4 #bb ,attraction ( ,gravitation1 cont9u$4 ,( ,weight4 ,( ! ,fall ( ,bodies4 ,( ! ,resi/ance ( ! ,air4 ,( ! ,asc5t ( ,light ,bodies4 ,,conv]sation ,,iii4 ,,on ,,! ,,laws ,,( ,,motion4 #cb ,( ,motion4 ,( ! ,in]tia ( ,bodies4 ,( ,=ce to produce ,motion4 ,direction ( ,motion4 ,velocity1 absolute & relative4 ,uni=m ,motion4 ,ret>d$ ,motion4 ,accel]at$ ,motion4 ,velocity ( ,fall+ ,bodies4 ,mom5tum4 ,action & ,reaction equal4 ,ela/icity ( ,bodies4 ,porosity ( ,bodies4 ,reflect$ ,motion4 ,angles ( ,incid5ce & ,reflection4 ,,conv]sation ,,iv4 ,,on ,,comp\nd ,,motion4 #df ,comp\nd ,motion1 ! result ( two opposite =ces4 ,( ,curvil9e> ,motion1 ! result ( two =ces4 ,c5tre ( ,motion1 ! po9t at re/1 :ile ! o!r p>ts ( ! body move r\nd x4 ,c5tre ( ,magnitude1 ! middle ( a body4 ,c5tripetal ,=ce1 t :i* impels a body t[>ds a fix$ c5tral po9t4 ,c5trifugal ,=ce1 t :i* impels a body to fly f ! c5tre4 ,fall ( ,bodies 9 a ,p>abola4 ,c5tre ( ,gravity1 ! po9t ab\t :i* ! p>ts balance ea* o!r4 ,,conv]sation ,v4 ,,on ,,! ,,me*anical ,,p[]s4 #ed ,( ! ,p[] ( ,ma*9es4 ,( ! ,lev] 9 g5]al4 ,( ! ,lev] ( ! fir/ k9d1 hav+ ! ,fulcrum betwe5 ! p[] & ! weight4 ,( ! ,lev] ( ! second k9d1 hav+ ! ,weight betwe5 ! p[] & ! fulcrum4 ,( ! ,lev] ( ! ?ird k9d1 hav+ ! ,p[] betwe5 ! fulcrum & ! weight4 ,( ! ,pulley4 ,( ! ,:eel & ,axle4 ,( ! ,incl9$ ,plane4 ,( ! ,w$ge4 ,( ! ,screw4 ,,conv]sation ,,vi4 ,,a/ronomy4 ,,causes ,,( ,,! ,,motion ,,( ,,! ,,heav5ly ,,bodies4 #gj ,( ! ,e>?'s annual motion4 ,( ! ,planets1 & _! motion4 ,( ! ,diurnal motion ( ! ,e>? & ,planets4 ,,conv]sation ,,vii4 ,,on ,,! ,,planets4 #hj ,( ! ,satellites & ,moons4 ,gravity dim9i%es z ! ,squ>e ( ! ,di/ance4 ,( ! ,sol> ,sy/em4 ,( ,comets4 ,con/ellations1 signs ( ! ,zodiac4 ,( ,cop]nicus1 ,newton1 c4 ,,conv]sation ,,viii4 ,,on ,,! ,,e>?4 #ia ,( ! ,t]re/rial ,globe4 ,( ! ,figure ( ! ,e>?4 ,( ! ,p5dulum4 ,( ! ,v>iation ( ! ,seasons1 & ( ! ,l5g? ( ,days & ,nights4 ,( ! ,causes ( ! ,heat ( ,summ]4 ,( ,sol>1 ,sid]ial1 & ,equal or ,mean ,"t4 ,,conv]sation ,,ix4 ,,on ,,! ,,moon4 #ajh ,( ! ,moon's ,motion4 ,phases ( ! ,moon4 ,eclipses ( ! ,moon4 ,eclipses ( ,jupit]'s ,moons4 ,( ,latitude & ,longitude4 ,( ! ,transits ( ! inf]ior ,planets4 ,( ! ,tides4 ,,conv]sation ,x4 ,,hydro/atics4 ,,on ,,! ,,me*anical ,,prop]ties ,,( ,,fluids4 #aah ,def9ition ( a ,fluid4 ,di/9ction betwe5 ,fluids & ,liquids4 ,( ,non-,ela/ic ,fluids1 sc>cely susceptible ( ,compression4 ,( ! ,cohesion ( ,fluids4 ,( _! ,gravitation4 ,( _! ,equilibrium4 ,( _! ,pressure4 ,( ,specific ,gravity4 ,( ! ,specific ,gravity ( ,bodies heavi] ?an ,wat]4 ,( ^? ( ! same weight z ,wat]4 ,( ^? light] ?an ,wat]4 ,( ! ,specific ,gravity ( ,fluids4 ,,conv]sation ,,xi4 ,,( ,,spr+s1 ,,f\nta9s1 c4 #abh ,( ! ,asc5t ( ,vap\r & ! ,=mation ( ,cl\ds4 ,( ! ,=mation & ,fall ( ,ra91 c4 ,( ! ,=mation ( ,spr+s4 ,( ,riv]s & ,lakes4 ,( ,f\nta9s4 ,,conv]sation ,,xii4 ,,pneumatics4 ,,on ,,! ,,me*anical ,,prop]ties ,,( ,,air4 #acf ,( ! ,spr+ or ,ela/icity ( ! ,air4 ,( ! ,weight ( ! ,air4 ,exp]im5ts ) ! ,air ,pump4 ,( ! ,b>omet]4 ,mode ( ,weigh+ ,air4 ,specific ,gravity ( ,air4 ,( ,pumps4 ,description ( ! ,suck+ ,pump4 ,description ( ! ,=c+ ,pump4 ,,conv]sation ,,xiii4 ,,on ,,w9d ,,& ,,s\nd4 #adf ,( ,w9d 9 ,g5]al4 ,( ! ,trade ,w9d4 ,( ! ,p]iodical ,trade ,w9ds4 ,( ! ,a]ial ,tides4 ,( ,s\nd 9 ,g5]al4 ,( ,sonor\s ,bodies4 ,( ,musical ,s\nds4 ,( ,concord or ,h>mony1 & ,melody4 ,,conv]sation ,,xiv4 ,,on ,,optics4 #aeg ,( ,lum9\s1 ,transp>5t1 & ,opaque ,bodies4 ,( ! ,radiation ( ,light4 ,( ,%ad[s4 ,( ! ,reflection ( ,light4 ,opaque ,bodies se5 only by ,reflect$ ,light4 ,vision ,expla9$4 ,cam]a ,obscura4 ,image ( ,objects on ! ,ret9a4 ,,conv]sation ,,xv4 ,,optics--cont9u$4 ,,( ,,! ,,angle ,,( ,,vision1 ,,& ,,reflection ,,( ,,mirrors4 #afh ,angle ( ,vision4 ,reflection ( ,pla9 ,mirrors4 ,reflection ( ,convex ,mirrors4 ,reflection ( ,concave ,mirrors4 ,,conv]sation ,,xvi4 ,,on ,,refraction ,,& ,,col\rs4 #agi ,transmission ( ,light by ,transp>5t ,bodies4 ,refraction4 ,refraction by ! ,atmosph]e4 ,refraction by a ,l5s4 ,refraction by ! ,prism4 ,( ,col\r f ! ,rays ( ,light4 ,( ! ,col\rs ( ,bodies4 ,,conv]sation ,,xvii4 ,,on ,,! ,,/ructure ,,( ,,! ,,eye1 ,,& ,,optical ,,in/rum5ts4 #aie ,description ( ! ,eye4 ,( ! ,image on ! ,ret9a4 ,refraction by ! ,hum\rs ( ! ,eye4 ,( ! use ( ,spectacles4 ,( ! ,s+le ,microscope4 ,( ! ,d\ble ,microscope4 ,( ! ,sol> ,microscope4 ,magic ,lan?orn4 ,refract+ ,telescope4 ,reflect+ ,telescope4 ,,gloss>y1 #bje ,,conv]sation ,i4 ,,on ,,g5]al ,,prop]ties ,,( ,,bodies4 ,,introduction4 ,,g5]al ,,prop]ties ,,( ,,bodies4 ,,imp5etrability4 ,,ext5sion4 ,,figure4 ,,divisibility4 ,,in]tia4 ,,attraction4 ,,attraction ,,( ,,cohesion4 ,,d5sity4 ,,r>ity4 ,,heat4 ,,attraction ,,( ,,gravitation4 ,,emily4 ,i mu/ reque/ y\r assi/ance1 my ,de> ,mrs4 ,b41 9 a *>ge :i* ,i h lately und]tak53 x is t ( in/ruct+ my y\nge/ si/]1 a task1 :i* ,i f9d proves m difficult ?an ,i _h at fir/ imag9$4 ,i c tea* h] ! common r\t9e ( *ildr5's lessons tol]ably well2 b %e is su* an inquisitive little creature1 t %e is n satisfi$ )\t an explanation ( e difficulty t occurs to h]1 & frequ5tly asks me que/ions :i* ,i am at a loss to answ]4 ,?is morn+1 = in/ance1 :5 ,i _h expla9$ to h] t ! _w 0 r\nd l a ball1 in/ead ( be+ flat z %e _h suppos$1 & t x 0 surr\nd$ by ! air1 %e ask$ me :at support$ x4 ,i told h] t x requir$ no support2 %e !n inquir$ :y x did n fall z e ?+ else did8 ,?is ,i confess p]plex$ me2 = ,i _h myself be5 satisfi$ ) le>n+ t ! _w float$ 9 ! air1 )\t consid]+ h[ unnatural x 0 t s heavy a body1 be>+ ! weight ( all o!r ?+s1 %\ld be able to support itself4 ,mrs4 ,b4 ,i make no d\bt1 my de>1 b t ,i %all be able to expla9 ?is difficulty to y2 b ,i believe t x w\ld be almo/ impossible to r5d] x intelligible to ! compreh5sion ( s "y a *ild z y\r si/] ,sophia4 ,y1 :o are n[ 9 y\r ?irte5? ye>1 may1 ,i ?9k1 ) great propriety1 le>n n only ! cause ( ?is p>ticul> fact1 b acquire a g5]al k ( ! laws by :i* ! natural _w is gov]n$4 ,emily4 ,( all ?+s1 x is :at ,i %\ld mo/ l to le>n2 b ,i 0 afraid x 0 too difficult a /udy ev5 at my age4 ,mrs4 ,b4 ,n :5 famili>ly expla9$3 if y h pati5ce to att5d1 ,i w mo/ will+ly give y all ! in=mation 9 my p[]4 ,y may p]haps f9d ! subject r dry at fir/2 b if ,i succe$ 9 expla9+ ! laws ( nature1 s z to make y und]/& !m1 ,i am sure t y w d]ive n only in/ruction1 b great amusem5t f t /udy4 ,emily4 ,i make no d\bt ( x1 ,mrs4 ,b42 & pray beg9 by expla9+ :y ! e>? requires no support2 = t is ! po9t :i* j n[ mo/ /rongly excites my curiosity4 ,mrs4 ,b4 ,my de> ,emily1 if ,i am to attempt to give y a g5]al idea ( ! laws ( nature1 :i* is no less ?an to introduce y to a k ( ! sci5ce ( natural philosophy1 x w be necess>y = u to proce$ ) "s degree ( regul>ity4 ,i d n wi% to conf9e y to ! sy/ematic ord] ( a sci5tific treatise1 b if we 7 m]ely to exam9e e vague "q t may *ance to occur1 our progress w\ld be b v sl[4 ,let u1 !re=e1 beg9 by tak+ a %ort survey ( ! g5]al prop]ties ( bodies1 "s ( :i* mu/ necess>ily be expla9$ be=e ,i c attempt to make y und]/& :y ! e>? requires no support4 ,:5 ,i speak ( bodies1 ,i mean sub/ances1 ( :atev] nature1 :e!r solid or fluid2 & matt] is ! g5]al t]m us$ to d5ote ! sub/ance1 :atev] its nature be1 ( :i* ! diff]5t bodies are compos$4 ,?us1 ! wood ( :i* ?is table is made1 ! wat] ) :i* ?is glass is fill$1 & ! air :i* we cont9ually brea!1 are ea* ( !m matt]4 ,emily4 ,i am v glad y h expla9$ ! mean+ ( ! ^w matt]1 z x has correct$ an errone\s conception ,i _h =m$ ( x3 ,i ?\ght t x 0 applicable to solid bodies only4 ,mrs4 ,b4 ,!re are c]ta9 prop]ties :i* appe> to be common to all bodies1 & are h5ce call$ ! ess5tial or inh]5t prop]ties ( bodies2 ^! are ,imp5etrability1 ,ext5sion1 ,figure1 ,divisibility1 ,in]tia & ,attraction4 ,^! are also call$ ! g5]al prop]ties ( bodies1 z we d n suppose any body to exi/ )\t !m4 ,by imp5etrability is meant ! prop]ty :i* bodies h ( occupy+ a c]ta9 space1 s t :]e "o body is1 ano!r c n be1 )\t displac+ ! =m]2 = two bodies c n exi/ 9 ! same place at ! same "t4 ,a liquid may be m easily remov$ ?an a solid body2 yet x is n ! less sub/antial1 s9ce x is z impossible = a liquid & a solid to occupy ! same space at ! same "t1 z = two solid bodies to d s4 ,= in/ance1 if y put a spoon into a glass full ( wat]1 ! wat] w fl[ ov] to make room = ! spoon4 ,emily4 ,i und]/& ?is p]fectly4 ,liquids are 9 reality z sub/antial or z imp5etrable z solid bodies1 & !y appe> less s1 only because !y are m easily displac$4 ,mrs4 ,b4 ,! air is a fluid diff]+ 9 its nature f liquids1 b no less imp5etrable4 ,if ,i endeav\r to fill ?is phial by plung+ x into ?is bason ( wat]1 ! air1 y see1 ru%es out ( ! phial 9 bubbles1 9 ord] to make way = ! wat]1 = ! air & ! wat] c n exi/ toge!r 9 ! same space1 any m ?an two h>d bodies2 & if ,i rev]se ?is goblet1 & plunge x p]p5dicul>ly into ! wat]1 s t ! air w n be able to escape1 ! wat] w no long] be able to fill ! goblet4 ,emily4 ,b x rises "s way into ! glass4 ,mrs4 ,b4 ,because ! wat] compresses or squeezes ! air into a small] space 9 ! upp] "p ( ! glass2 b1 z long z x rema9s !re1 no o!r body c occupy ! same place4 ,emily4 ,a difficulty has j occurr$ to me1 ) reg>d to ! imp5etrability ( solid bodies2 if a nail is driv5 into a piece ( wood1 x p5etrates x1 & bo? ! wood & ! nail occupy ! same space t ! wood alone did be=e8 ,mrs4 ,b4 ,! nail p5etrates betwe5 ! p>ticles ( ! wood1 by =c+ !m to make way = x2 = y "k t n a s+le atom ( wood c rema9 9 ! space :i* ! nail occupies2 & if ! wood is n increas$ 9 size by ! addition ( ! nail1 x is because wood is a por\s sub/ance1 l sponge1 ! p>ticles ( :i* may be compress$ or squeez$ clos] toge!r2 & x is ?us t !y make way = ! nail4 ,we may n[ proce$ to ! next g5]al prop]ty ( bodies1 ext5sion4 ,a body :i* occupies a c]ta9 space mu/ necess>ily h ext5sion2 t is to say1 l5g?1 bread? & dep? or ?ickness2 ^! are call$ ! dim5sions ( ext5sion3 c y =m an idea ( any body )\t !m8 ,emily4 ,no2 c]ta9ly ,i c n2 ?\gh ^! dim5sions mu/1 ( c\rse v>y extremely 9 diff]5t bodies4 ,! l5g?1 bread? & dep? ( a box1 or ( a ?imble1 are v diff]5t f ^? ( a walk+ /ick1 or ( a hair4 ,b is n height also a dim5sion ( ext5sion8 ,mrs ,b4 ,height & dep? are ! same dim5sion1 consid]$ 9 diff]5t po9ts ( view2 if y measure a body1 or a space1 f ! top to ! bottom1 y call x dep?2 if f ! bottom upw>ds1 y call x height2 ?us ! dep? & height ( a box are1 9 fact1 ! same ?+4 ,emily4 ,v true2 a mom5t's consid]ation w\ld h enabl$ me to discov] t2 & bread? & wid? are also ! same dim5sion4 ,mrs4 ,b4 ,yes2 ! limits ( ext5sion con/itute figure or %ape4 ,y conceive t a body hav+ l5g?1 bread? & dep?1 c n be )\t =m1 ei!r symmetrical or irregul>8 ,emily4 ,und\bt$ly2 & ?is prop]ty admits ( almo/ an inf9ite v>iety4 ,mrs4 ,b4 ,nature has assign$ regul> =ms to _m ( h] productions4 ,! natural =m ( v>i\s m9]al sub/ances is t ( cry/als1 ( :i* !re is a great v>iety4 ,_m ( !m are v beautiful1 & no less rem>kable by _! transp>5cy or col\r1 ?an by ! p]fect regul>ity ( _! =ms1 z may be se5 9 ! v>i\s museums & collections ( natural hi/ory4 ,! vegetable & animal creation appe>s less symmetrical1 b is /ill m div]sifi$ 9 figure ?an ! m9]al k+dom4 ,manufactur$ sub/ances assume ! v>i\s arbitr>y =ms :i* ! art ( man designs = !m2 & an inf9ite numb] ( irregul> =ms are produc$ by fractures & by ! dismemb]m5t ( ! p>ts ( bodies4 ,emily4 ,su* z a piece ( brok5 *9a1 or glass8 ,mrs4 ,b4 ,or ! masses & fragm5ts ( /one1 & o!r m9]al sub/ances1 :i* are dug out ( ! e>?1 or f\nd ^u its surface2 _m ( :i*1 al?\gh compos$ ( m9ute cry/als1 are 9 ! lump ( an irregul> =m4 ,we may n[ proce$ to divisibility2 t is to say1 a susceptibility ( be+ divid$ into an indef9ite numb] ( p>ts4 ,take any small quantity ( matt]1 a gra9 ( s& = in/ance1 & cut x into two p>ts2 ^! two p>ts might be aga9 divid$1 _h we in/rum5ts suffici5tly f9e = ! purpose2 & if by means ( p\nd+1 gr9d+1 & o!r simil> me?ods1 we c>ry ?is division to ! greate/ possible ext5t1 & r$uce ! body to its f9e/ imag9able p>ticles1 yet n "o ( ! p>ticles w be de/roy$1 b w ea* conta9 z _m halves & qu>t]s1 z did ! :ole gra94 ,! dissolv+ ( a solid body 9 a liquid1 af=ds a v /rik+ example ( ! extreme divisibility ( matt]2 :5 y sweet5 a cup ( tea1 = in/ance1 ) :at m9ut5ess ! sug> mu/ be divid$ to be diffus$ ?r\gh\t ! :ole ( ! liquid4 ,emily4 ,& if y p\r a few drops ( r$ w9e into a glass ( wat]1 !y imm$iately t+e ! :ole ( ! wat]1 & mu/ !re=e be diffus$ ?r\gh\t x4 ,mrs4 ,b4 ,exactly s2 & ! p]fume ( ?is lav5d] wat] w be almo/ z in/antane\sly diffus$ ?r\gh\t ! room1 if ,i take out ! /opp]4 ,emily4 ,b 9 ?is case x is only ! p]fume ( ! lav5d]1 & n ! wat] itself t is diffus$ 9 ! room4 ,mrs4 ,b4 ,! od\r or smell ( a body is "p ( ! body itself1 & is produc$ by v m9ute p>ticles or exhalations :i* escape f ! odorif]\s bodies4 ,x w\ld be impossible t y %\ld smell ! lav5d] wat]1 if p>ticles ( x did n come 9 actual contact ) y\r nose4 ,emily4 ,b :5 ,i smell a fl[]1 ,i see no vap\r rise f x2 & yet ,i p]ceive ! smell at a consid]able di/ance4 ,mrs4 ,b4 ,y c\ld1 ,i assure y1 no m smell a fl[]1 ! odorif]\s p>ticles ( :i* did n t\* y\r nose1 ?an y c\ld ta/e a fruit1 ! flav\r$ p>ticles ( :i* did n come 9 contact ) y\r tongue4 ,emily4 ,t is wond]ful inde$2 ! p>ticles !n1 :i* exhale f ! fl[] & f ! lav5d] wat]1 are1 ,i suppose1 too small to be visible8 ,mrs4 ,b4 ,c]ta9ly3 y may =m "s idea ( _! extreme m9ut5ess1 f ! imm5se numb] :i* mu/ h escap$ 9 ord] to p]fume ! :ole room2 & yet !re is no s5sible dim9ution ( ! liquid 9 ! phial4 ,emily4 ,b ! quantity mu/ really be dim9i%$8 ,mrs4 ,b4 ,und\bt$ly2 & 7 y to leave ! bottle op5 a suffici5t l5g? ( "t1 ! :ole ( ! wat] w\ld evaporate & disappe>4 ,b ?\gh s m9utely subdivid$ z to be imp]ceptible to any ( our s5ses1 ea* p>ticle w\ld cont9ue to exi/2 = x is n )9 ! p[] ( man to de/roy a s+le p>ticle ( matt]3 nor is !re any reason to suppose t 9 nature an atom is ev] annihilat$4 ,emily4 ,yet1 :5 a body is burnt to a%es1 "p ( x1 at lea/1 appe>s to be effectually de/roy$3 look h[ small is ! residue ( a%es 9 ! fire place1 f all ! fuel :i* has be5 consum$ )9 x4 ,mrs4 ,b4 ,t "p ( ! fuel1 :i* y suppose to be de/roy$1 evaporates 9 ! =m ( smoke1 & vap\r1 & air1 :il/ ! rema9d] is r$uc$ to a%es4 ,a body1 9 burn+1 und]goes no d\bt v rem>kable *anges2 x is g5]ally subdivid$2 its =m & col\r alt]$2 its ext5sion increas$3 b ! v>i\s p>ts1 into :i* x has be5 sep>at$ by combu/ion1 cont9ue 9 exi/5ce1 & reta9 all ! ess5tial prop]ties ( bodies4 ,emily4 ,b t "p ( a burnt body :i* evaporates 9 smoke has no figure2 smoke1 x is true1 asc5ds 9 columns into ! air1 b x is soon s mu* diffus$ z to lose all =m2 x becomes inde$ invisible4 ,mrs4 ,b4 ,invisible1 ,i all[2 b we mu/ n imag9e t :at we no long] see no long] exi/s4 ,7 e p>ticle ( matt] t becomes invisible annihilat$1 ! _w itself w\ld 9 ! c\rse ( "t be de/roy$4 ,! p>ticles ( smoke1 :5 diffus$ 9 ! air1 cont9ue /ill to be p>ticles ( matt] z well z :5 m closely unit$ 9 ! =m ( coals3 !y are really z sub/antial 9 ! "o /ate z 9 ! o!r1 & equally s :5 by _! extreme subdivision !y become invisible4 ,no p>ticle ( matt] is ev] de/roy$3 ?is is a pr9ciple y mu/ con/antly rememb]4 ,e ?+ 9 nature decays & corrupts 9 ! lapse ( "t4 ,we die1 & our bodies m\ld] to du/2 b n a s+le atom ( !m is lo/2 !y s]ve to n\ri% ! e>?1 :5ce1 :ile liv+1 !y drew _! support4 ,! next ess5tial prop]ty ( matt] is call$ in]tia or inactivity2 ?is ^w expresses ! resi/ance :i* matt] makes to a *ange f a /ate ( re/1 to t ( motion1 or f a /ate ( motion to t ( re/4 ,bodies are equally incapable ( *ang+ _! actual /ate1 :e!r x be ( motion or ( re/4 ,y "k t x requires =ce to put a body :i* is at re/ 9 motion2 an ex]tion ( /r5g? is also requisite to /op a body :i* is already 9 motion4 ,! resi/ance ( ! body to a *ange ( /ate1 9 ei!r case1 arises f its in]tia4 ,emily4 ,9 play+ at base-ball ,i am oblig$ to use all my /r5g? to give a rapid motion to ! ball2 & :5 ,i h to cat* x1 ,i am sure ,i feel ! resi/ance x makes to be+ /opp$4 ,b if ,i did n cat* x1 x w\ld soon fall to ! gr\nd & /op ( itself4 ,mrs4 ,b4 ,matt] be+ in]t x is z incapable ( /opp+ ( itself z x is ( putt+ itself into motion3 :5 ! ball ceases to move1 !re=e1 x mu/ be /opp$ by "s o!r cause or p[]2 b z x is "o ) :i* y are yet unacqua9t$1 we c n at pres5t inve/igate its effects4 ,! la/ prop]ty :i* appe>s to be common to all bodies is attraction4 ,all bodies consi/ ( inf9itely small p>ticles ( matt]1 ea* ( :i* possesses ! p[] ( attract+ or draw+ t[>ds x1 & unit+ ) any o!r p>ticle suffici5tly ne> to be )9 ! influ5ce ( its attraction2 b 9 m9ute p>ticles ?is p[] ext5ds to s v small a di/ance ar\nd !m1 t its effect is n s5sible1 unless !y are 7or at lea/ appe> to be7 9 contact2 x !n makes !m /ick or adh]e toge!r1 & is h5ce call$ ! attraction ( cohesion4 ,)\t ?is p[]1 solid bodies w\ld fall 9 pieces1 or r crumble to atoms4 ,emily4 ,i am s mu* accu/om$ to see bodies firm & solid1 t x nev] occurr$ to me t any p[] 0 requisite to unite ! p>ticles ( :i* !y are compos$4 ,b ! attraction ( cohesion does n1 ,i suppose1 exi/ 9 liquids2 = ! p>ticles ( liquids d n rema9 toge!r s z to =m a body1 unless conf9$ 9 a vessel8 ,mrs4 ,b4 ,i beg y\r p>don2 x is ! attraction ( cohesion :i* holds ?is drop ( wat] susp5d$ at ! end ( my f+]1 & keeps ! m9ute wat]y p>ticles ( :i* x is compos$ unit$4 ,b z ?is p[] is /rong] 9 proportion z ! p>ticles ( bodies are m closely unit$1 ! cohesive attraction ( solid bodies is mu* great] ?an t ( fluids4 ,! ?9n] & light] a fluid is1 ! less is ! cohesive attraction ( its p>ticles1 because !y are fur!r ap>t2 & 9 ela/ic fluids1 su* z air1 !re is no cohesive attraction among ! p>ticles4 ,emily4 ,t is v =tunate2 = x w\ld be impossible to brea! ! air 9 a solid mass2 or ev5 9 a liquid /ate4 ,b is ! air a body ( ! same nature z o!r bodies8 ,mrs4 ,b4 ,und\bt$ly1 9 all ess5tial prop]ties4 ,emily4 ,yet y say t x does n possess "o ( ! g5]al prop]ties ( bodies--attraction4 ,mrs4 ,b4 ,! p>ticles ( air are n de/itute ( ! p[] ( attraction1 b !y are too f> di/ant f ea* o!r to be influ5c$ by x s z to produce cohesion3 & ! utmo/ ef=ts ( human art h prov$ ineffectual 9 ! attempt to compress !m1 s z to br+ !m )9 ! sph]e ( ea* o!r's attraction1 & make !m coh]e4 ,emily4 ,if s1 h[ is x possible to prove t !y are end[$ ) ?is p[]8 ,mrs4 ,b4 ,! air is =m$ ( p>ticles precisely ( ! same nature z ^? :i* ent] into ! composition ( liquid & solid bodies1 9 ea* ( :i* we h a pro( ( _! attraction4 ,emily4 ,x is !n1 ,i suppose1 ow+ to ! diff]5t degrees ( cohesive attraction 9 diff]5t sub/ances1 t !y are h>d or s(t1 & t liquids are ?ick or ?94 ,mrs4 ,b4 ,yes2 b y w\ld express y\r mean+ bett] by ! t]m d5sity1 :i* d5otes ! degree ( clos5ess & compactness ( ! p>ticles ( a body4 ,9 philosophical language1 d5sity is said to be t prop]ty ( bodies by :i* !y conta9 a c]ta9 quantity ( matt]1 "u a c]ta9 bulk or magnitude4 ,r>ity is ! contr>y ( d5sity2 x d5otes ! ?9ness & subtilty ( bodies3 ?us y w\ld say t m]cury or quicksilv] 0 a v d5se fluid2 e!r1 a v r>e "o4 ,^? bodies :i* are ! mo/ d5se1 d n always coh]e ! mo/ /rongly2 lead is m d5se ?an iron1 yet its p>ticles are m easily sep>at$4 ,c>ol9e4 ,b h[ are we to judge ( ! quantity ( matt] conta9$ 9 a c]ta9 bulk8 ,mrs4 ,b4 ,by ! weight3 "u ! same bulk bodies are said to be d5se 9 proportion z !y are heavy4 ,emily4 ,!n we may say t metals are d5se bodies1 wood comp>atively a r>e "o1 c4 ,b1 ,mrs4 ,b41 :5 ! p>ticles ( a body are s ne> z to attract ea* o!r1 ! effect ( ?is p[] mu/ increase z !y are br\ght by x clos] toge!r2 s t "o w\ld suppose t ! body w\ld gradually augm5t 9 d5sity1 till x 0 impossible = its p>ticles to be m closely unit$4 ,n[1 we "k t ?is is n ! case2 = s(t bodies1 su* z cork1 sponge1 or butt]1 nev] become1 9 consequ5ce ( ! increas+ attraction ( _! p>ticles1 z h>d z iron8 ,mrs4 ,b4 ,9 su* bodies z cork & sponge1 ! p>ticles :i* come 9 contact are s few z to produce b a slight degree ( cohesion3 !y are por\s bodies1 :i*1 ow+ to ! peculi> arrangem5t ( _! p>ticles1 ab\nd ) int]/ices1 or pores1 :i* sep>ate ! p>ticles4 ,b !re is also a fluid mu* m subtile ?an air1 :i* p]vades all bodies1 ?is is heat4 ,heat ins9uates itself m or less betwe5 ! p>ticles ( all bodies1 & =ces !m asund]2 y may !re=e consid] heat1 & ! attraction ( cohesion1 z con/antly act+ 9 opposition to ea* o!r4 ,emily4 ,! "o endeav\r+ to r5d a body to pieces1 ! o!r to keep its p>ts firmly unit$4 ,mrs4 ,b4 ,& x is ?is /ruggle betwe5 ! cont5d+ =ces ( heat & attraction1 :i* prev5ts ! extreme degree ( d5sity :i* w\ld result f ! sole influ5ce ( ! attraction ( cohesion4 ,emily4 ,! m a body is heat$ !n1 ! m its p>ticles w be sep>at$4 ,mrs4 ,b4 ,c]ta9ly3 we f9d t bodies n only swell or dilate1 b lose _! cohesion1 by heat3 ?is effect is v s5sible 9 butt]1 = in/ance1 :i* exp&s by ! application ( heat1 till at l5g? ! attraction ( cohesion is s f> dim9i%$ t ! p>ticles sep>ate1 & ! butt] becomes liquid4 ,a simil> effect is produc$ by heat on metals1 & all bodies susceptible ( be+ melt$4 ,liquids1 y "k1 are made to boil by ! application ( heat2 ! attraction ( cohesion !n yields entirely to ! repulsive p[]2 ! p>ticles are totally sep>at$ & conv]t$ into /eam or vap\r4 ,b ! ag5cy ( heat is 9 no body m s5sible ?an 9 air1 :i* dilates & contracts by its increase or dim9ution 9 a v rem>kable degree4 ,emily4 ,! effects ( heat appe> to be "o ( ! mo/ int]e/+ p>ts ( natural philosophy4 ,mrs4 ,b4 ,t is true2 b heat is s intimately connect$ ) *emi/ry1 t y mu/ all[ me to def] ! inve/igation ( its prop]ties till y become acqua9t$ ) t sci5ce4 ,to return to its antagoni/1 ! attraction ( cohesion2 x is ?is p[] :i* re/ores to vap\r its liquid =m1 :i* unites x into drops :5 x falls to e>? 9 a %[] ( ra91 :i* ga!rs ! dew into brilliant gems on ! blades ( grass4 ,emily4 ,& ,i h (t5 obs]v$ t aft] a %[]1 ! wat] collects into l>ge drops on ! leaves ( plants2 b ,i _c say t ,i p]fectly und]/& h[ ! attraction ( cohesion produces ?is effect4 ,mrs4 ,b4 ,ra91 :5 x fir/ leaves ! cl\ds1 is n 9 ! =m ( drops1 b 9 t ( mi/ or vap\r1 :i* is compos$ ( v small wat]y p>ticles2 ^! 9 _! desc5t mutually attract ea* o!r1 & ^? t are suffici5tly ne> 9 consequ5ce unite & =m a drop1 & ?us ! mi/ is trans=m$ into a %[]4 ,! dew also 0 orig9ally 9 a /ate ( vap\r1 b is1 by ! mutual attraction ( ! p>ticles1 =m$ into small globules on ! blades ( grass3 9 a simil> mann] ! ra9 ^u ! leaf collects into l>ge drops1 :i* :5 !y become too heavy = ! leaf to support1 fall to ! gr\nd4 ,emily4 ,all ?is is wond]fully curi\s6 ,i am almo/ bewild]$ ) surprise & admiration at ! numb] ( new ideas ,i h already acquir$4 ,mrs4 ,b4 ,e /ep t y advance 9 ! pursuit ( natural sci5ce1 w fill y\r m9d ) admiration & gratitude t[>ds its ,div9e ,au?or4 ,9 ! /udy ( natural philosophy1 we mu/ consid] ourselves z read+ ! book ( nature1 9 :i* ! b\ntiful goodness & wisdom ( ,god are reveal$ to all mank9d2 no /udy c t5d m to purify ! he>t1 & raise x to a religi\s contemplation ( ! ,div9e p]fections4 ,!re is ano!r curi\s effect ( ! attraction ( cohesion :i* ,i mu/ po9t out to y2 ?is is call$ capill>y attraction4 ,x enables liquids to rise above _! ord9>y level 9 capill>y tubes3 ^! are tubes1 ! bores ( :i* are s extremely small t liquids asc5d )9 !m1 f ! cohesive attraction betwe5 ! p>ticles ( ! liquid & ! int]ior surface ( ! tube4 ,d y p]ceive ! wat] ris+ 9 ?is small glass tube1 above its level 9 ! goblet ( wat]1 into :i* ,i h put "o end ( x8 ,emily4 ,oh yes2 ,i see x sl[ly creep+ up ! tube1 b n[ x is /ation>y3 w x rise no high]8 ,mrs4 ,b4 ,no2 because ! cohesive attraction betwe5 ! wat] & ! int]nal surface ( ! tube is n[ balanc$ by ! weight ( ! wat] )9 x2 if ! bore ( ! tube 7 n>r[] ! wat] w\ld rise high]2 & if y imm]se sev]al tubes ( bores ( diff]5t sizes1 y w see x rise to diff]5t heights 9 ea* ( !m4 ,9 mak+ ?is exp]im5t1 y %\ld col\r ! wat] ) a little r$ w9e1 9 ord] to r5d] ! effect m obvi\s4 ,all por\s sub/ances1 su* z sponge1 bread1 l951 c4 may be consid]$ z collections ( capill>y tubes3 if y dip "o end ( a lump ( sug> into wat]1 ! fluid w rise 9 x1 & wet x consid]ably above ! surface ( ! wat] into :i* y dip x4 ,emily4 ,9 mak+ tea ,i h (t5 obs]v$ t effect1 )\t be+ able to acc\nt = x4 ,mrs4 ,b4 ,n[ t y are acqua9t$ ) ! attraction ( cohesion1 ,i mu/ endeav\r to expla9 to y t ( ,gravitation1 :i* is probably a modification ( ! same p[]2 ! fir/ is p]ceptible only 9 v m9ute p>ticles1 & at v small di/ances2 ! o!r acts on ! l>ge/ bodies1 & ext5ds to imm5se di/ances4 ,emily4 ,y a/oni% me3 surely y d n mean to say t l>ge bodies attract ea* o!r8 ,mrs4 ,b4 ,inde$ ,i d3 let u take1 = example1 "o ( ! l>ge/ bodies 9 nature1 & obs]ve :e!r x does n attract o!r bodies4 ,:at is x t occasions ! fall ( ?is book1 :5 ,i no long] support x8 ,emily4 ,c x be ! attraction ( ! e>?8 ,i ?\ght t all bodies _h a natural t5d5cy to fall4 ,mrs4 ,b4 ,!y h a natural t5d5cy to fall1 x is true2 b t t5d5cy is produc$ entirely by ! attraction ( ! e>?3 ! e>? be+ s mu* l>g] ?an any body on its surface1 =ces e body1 :i* is n support$1 to fall ^u x4 ,emily4 ,if ! t5d5cy :i* bodies h to fall results f ! e>?'s attractive p[]1 ! e>? itself c h no su* t5d5cy1 s9ce x _c attract itself1 & !re=e x requires no support to prev5t x f fall+4 ,yet ! idea t bodies d n fall ( _! own accord1 b t !y are drawn t[>ds ! e>? by its attraction1 is s new & /range to me1 t ,i "k n h[ to reconcile myself to x4 ,mrs4 ,b4 ,:5 y are accu/om$ to consid] ! fall ( bodies z dep5d+ on ?is cause1 x w appe> to y z natural1 & surely mu* m satisfactory1 ?an if ! cause ( _! t5d5cy to fall 7 totally unkn[n4 ,?us y und]/& t all matt] is attractive1 f ! smalle/ p>ticle to ! l>ge/ mass2 & t bodies attract ea* o!r ) a =ce proportional to ! quantity ( matt] !y conta94 ,emily4 ,i d n p]ceive any diff]5ce betwe5 ! attraction ( cohesion & t ( gravitation2 is x n because e p>ticle ( matt] is end[$ ) an attractive p[]1 t l>ge bodies consi/+ ( a great numb] ( p>ticles1 are s /rongly attractive8 ,mrs4 ,b4 ,true4 ,!re is1 h[ev]1 ?is diff]5ce betwe5 ! attraction ( p>ticles & t ( masses1 t ! =m] takes place only :5 ! p>ticles are contigu\s1 :il/ ! latt] is ex]t$ :5 ! masses are f> f ea* o!r4 ,! attraction ( p>ticles frequ5tly c\nt]acts ! attraction ( gravitation4 ,( ?is y h an in/ance 9 ! attraction ( capill>y tubes1 9 :i* liquids asc5d by ! attraction ( cohesion1 9 opposition to t ( gravity4 ,x is on ?is acc\nt t x is necess>y t ! bore ( ! tube %\ld be extremely small2 = if ! column ( wat] )9 ! tube is n v m9ute1 ! attraction ( cohesion w\ld n be able ei!r to raise or support x 9 opposition to its gravity2 because ! increase ( weight1 9 a column ( wat] ( a giv5 height1 is mu* great] ?an ! increase 9 ! attract+ surface ( ! tube1 :5 its size is increas$4 ,y may obs]ve also1 t all solid bodies are enabl$ by ! =ce ( ! cohesive attraction ( _! p>ticles to resi/ t ( gravity1 :i* w\ld o!rwise disunite !m1 & br+ !m to a level ) ! gr\nd1 z x does 9 ! case ( a liquid1 ! cohesive attraction ( :i* is n suffici5t to enable x to resi/ ! p[] ( gravity4 ,emily4 ,& "s solid bodies appe> to be ( ?is nature1 z s&1 & p[d] = in/ance3 !re is no attraction ( cohesion betwe5 _! p>ticles8 ,mrs4 ,b4 ,e gra9 ( p[d]1 or s&1 is compos$ ( a great numb] ( o!r m m9ute p>ticles1 firmly unit$ by ! attraction ( cohesion2 b among/ ! sep>ate gra9s !re is no s5sible attraction1 because !y are n 9 suffici5tly close contact4 ,emily4 ,yet !y actually t\* ea* o!r8 ,mrs4 ,b4 ,! surface ( bodies is 9 g5]al s r\gh & unev51 t :5 9 app>5t contact1 !y t\* ea* o!r only by a few po9ts4 ,?us1 :5 ,i lay ?is book ^u ! table1 ! b9d+ ( :i* appe>s p]fectly smoo?1 s few ( ! p>ticles ( its "u surface come 9 contact ) ! table1 t no s5sible degree ( cohesive attraction takes place2 = y see t x does n /ick or coh]e to ! table1 & ,i f9d no difficulty 9 lift+ x (f4 ,x is only :5 surfaces1 p]fectly flat & well poli%$1 are plac$ 9 contact1 t ! p>ticles approa* 9 suffici5t numb]1 & closely en\gh1 to produce a s5sible degree ( cohesive attraction4 ,"h are two plates ( poli%$ metal1 ,i press _! flat surfaces toge!r1 hav+ previ\sly int]pos$ a few drops ( oil1 to fill up e little por\s vacancy4 ,n[ try to sep>ate !m4 ,emily4 ,x requires an ef=t beyond my /r5g?1 ?\gh !re are h&les = ! purpose ( pull+ !m asund]4 ,is ! firm adhesion ( ! two plates m]ely ow+ to ! attraction ( cohesion8 ,mrs4 ,b4 ,!re is no =ce m p[]ful1 s9ce x is by ?is t ! p>ticles ( ! h>de/ bodies are held toge!r4 ,x w\ld require a weight ( sev]al p\nds to sep>ate ^! plates4 ,9 ! pres5t example1 h[ev]1 mu* ( ! cohesive =ce is due to ! attraction subsi/+ betwe5 ! metal & ! oil :i* is int]pos$2 z )\t ?is1 or "s o!r fluid1 ! po9ts ( contact w\ld /ill be comp>atively few1 al?\gh we may h employ$ our utmo/ art1 9 giv+ flat surfaces to ! plates4 ,emily4 ,9 mak+ a kaleidoscope1 ,i recollect t ! two plates ( glass1 :i* 7 to s]ve z mirrors1 /uck s fa/ toge!r1 t ,i imag9$ "s ( ! gum ,i _h be5 us+ _h by *ance be5 int]pos$ betwe5 !m2 b ,i am n[ conv9c$ t x 0 _! own natural cohesive attraction :i* produc$ ?is effect4 ,mrs4 ,b4 ,v probably x 0 s2 = plate-glass has an extremely smoo?1 flat surface1 admitt+ ( ! contact ( a great numb] ( p>ticles1 :5 two plates are laid ^u ea* o!r4 ,emily4 ,b1 ,mrs4 ,b41 ! cohesive attraction ( "s sub/ances is mu* great] ?an t ( o!rs2 ?us glue1 gum & pa/e1 coh]e ) s+ul> t5acity4 ,mrs4 ,b4 ,bodies :i* diff] 9 _! natures 9 o!r respects1 diff] also 9 _! cohesive attraction2 x is probable t !re are no two bodies1 ! p>ticles ( :i* attract ea* o!r ) precisely ! same =ce4 ,!re are "s o!r modifications ( attraction peculi> to c]ta9 bodies2 namely1 t ( magnetism1 ( electricity1 & ( aff9ity1 or *emical attraction2 b we %all conf9e our att5tion m]ely to ! attraction ( cohesion & ( gravity2 ! exam9ation ( ! latt] we %all resume at our next meet+4 ,que/ions #a4 7,pg4 #aj7 ,:at is int5d$ by ! t]m bodies8 #b4 7,pg4 #aj7 ,is ! t]m matt]1 re/rict$ to sub/ances ( a p>ticul> k9d8 #c4 7,pg4 #aj7 ,"n ^? prop]ties ( bodies1 :i* are call$ inh]5t4 #d4 7,pg4 #aj7 ,:at is meant by imp5etrability8 #e4 7,pg4 #aj7 ,c a liquid be said to be imp5etrable8 #f4 7,pg4 #aa7 ,h[ c y prove t air is imp5etrable8 #g4 7,pg4 #aa7 ,if air is imp5etrable1 :at causes ! wat] to rise "s way into a goblet1 if ,i plunge x into wat] ) its m\? d[nw>d8 #h4 7,pg4 #aa7 ,:5 ,i drive a nail into wood1 d n bo? ! iron & ! wood occupy ! same space8 #i4 7,pg4 #aa7 ,9 h[ _m directions1 is a body said to h ext5sion8 #aj4 7,pg4 #aa7 ,h[ d we di/+ui% ! t]ms height & dep?8 #aa4 7,pg4 #ab7 ,:at con/itutes ! figure1 or =m ( a body8 #ab4 7,pg4 #ab7 ,:at is said respect+ ! =m ( m9]als8 #ac4 7,pg4 #ab7 ,:at ( ! vegetable & animal creation8 #ad4 7,pg4 #ab7 ,:at ( artificial1 & accid5tal =ms8 #ae4 7,pg4 #ab7 ,:at is meant by divisibility8 #af4 7,pg4 #ab7 ,:at examples c y give1 to prove t ! p>ticles ( a body are m9ute 9 ! extreme8 #ag4 7,pg4 #ac7 ,:at produces ! od\r ( bodies8 #ah4 7,pg4 #ac7 ,h[ d od\rs exemplify ! m9ut5ess ( ! p>ticles ( matt]8 #ai4 7,pg4 #ac7 ,c matt] be 9 any way annihilat$8 #bj4 7,pg4 #ac7 ,:at becomes ( ! fuel1 :i* disappe>s 9 our fires8 #ba4 7,pg4 #ad7 ,h[ c t "p :i* evaporates1 be /ill said to possess a sub/antial =m8 #bb4 7,pg4 #ad7 ,:at d we mean by in]tia8 #bc4 7,pg4 #ad7 ,give an example to prove t =ce is necess>y1 ei!r to give or to /op motion4 #bd4 7,pg4 #ad7 ,:at g5]al p[] d ! p>ticles ( matt] ex]t ^u o!r p>ticles8 #be4 7,pg4 #ae7 ,:at is t species ( attraction call$1 :i* keeps bodies 9 a solid /ate8 #bf4 7,pg4 #ae7 ,does ! attraction ( cohesion exi/ 9 liquids1 & h[ is its exi/5ce prov$8 #bg4 7,pg4 #ae7 ,if ! p>ticles ( air attract ea* o!r1 :y d !y n coh]e8 #bh4 7,pg4 #ae7 ,f :at !n d y inf] t !y possess attraction8 #bi4 7,pg4 #ae7 ,h[ d y acc\nt = "s bodies be+ h>d & o!rs s(t8 #cj4 7,pg4 #af7 ,:at is meant by ! t]m d5sity8 #ca4 7,pg4 #af7 ,d ! mo/ d5se bodies always coh]e ! mo/ /rongly8 #cb4 7,pg4 #af7 ,h[ d we "k t "o body is m d5se ?an ano!r8 #cc4 7,pg4 #af7 ,:at is !re :i* acts 9 opposition to cohesive attraction1 t5d+ to sep>ate ! p>ticles ( bodies8 #cd4 7,pg4 #ag7 ,:at w\ld be ! consequ5ce if ! repulsive p[] ( heat 7 n ex]t$8 #ce4 7,pg4 #ag7 ,if we cont9ue to increase ! heat1 :at effects w x produce on bodies8 #cf4 7,pg4 #ag7 ,:at body has its dim5sions mo/ s5sibly affect$ by *ange ( temp]ature8 #cg4 7,pg4 #ag7 ,:at p[] re/ores vap\rs to ! liquid =m8 #ch4 7,pg4 #ag7 ,:at examples c y give8 #ci4 7,pg4 #ag7 ,h[ are drops ( ra9 & ( dew said to be =m$8 #dj4 7,pg4 #ah7 ,:at is meant by a capill>y tube8 #da4 7,pg4 #ah7 ,:at effect does attraction produce :5 ^! are imm]s$ 9 wat]8 #db4 7,pg4 #ah7 ,:at is ! reason t ! wat] rises to a c]ta9 height only8 #dc4 7,pg4 #ah7 ,give "s famili> examples ( capill>y attraction4 #dd4 7,pg4 #ah7 ,9 :at does gravitation diff] f cohesive attraction8 #de4 7,pg4 #ah7 ,:at causes bodies ne> ! e>?'s surface1 to h a t5d5cy to fall t[>ds x8 #df4 7,pg4 #ai7 ,:at rem>kable diff]5ce is !re betwe5 ! attraction ( gravitation1 & t ( cohesion8 #dg4 7,pg4 #ai7 ,9 :at in/ances does ! p[] ( cohesion c\nt]act t ( gravitation8 #dh4 7,pg4 #ai7 ,:y w wat] rise to a less height1 if ! size ( ! tube is increas$8 #di4 7,pg4 #bj7 ,:y d n two bodies coh]e1 :5 laid ^u ea* o!r8 #ej4 7,pg4 #bj7 ,c two bodies be made suffici5tly flat to coh]e ) consid]able =ce8 #ea4 7,pg4 #bj7 ,:at is ! reason t ! adhesion is great] :5 oil is int]pos$8 #eb4 7,pg4 #ba7 ,:at o!r modifications ( attraction are !re1 besides ^? ( cohesion & ( gravitation8 ,,conv]sation ,,ii4 ,,on ,,! ,,attraction ,,( ,,gravity4 ,,attraction ,,( ,,gravitation1 ,,cont9u$4 ,,( ,,weight4 ,,( ,,! ,,fall ,,( ,,bodies4 ,,( ,,! ,,resi/ance ,,( ,,! ,,air4 ,,( ,,! ,,asc5t ,,( ,,light ,,bodies4 ,,emily4 ,i h relat$ to my si/] ,c>ol9e all t y h taught me ( natural philosophy1 & %e has be5 s mu* delight$ by x1 t %e hopes y w h ! goodness to admit h] to y\r lessons4 ,mrs4 ,b4 ,v will+ly2 b ,i did n ?9k y _h any ta/e = /udies ( ?is nature1 ,c>ol9e4 ,c>ol9e4 ,i confess1 ,mrs4 ,b41 t hi!rto ,i _h =m$ no v agreeable idea ei!r ( philosophy1 or philosoph]s2 b :at ,emily has told me has excit$ my curiosity s mu*1 t ,i %all be highly pleas$ if y w all[ me to become "o ( y\r pupils4 ,mrs4 ,b4 ,i fe> t ,i %all n f9d y s tractable a s*ol> z ,emily2 ,i "k t y are mu* bias$ 9 fav\r ( y\r own op9ions4 ,c>ol9e4 ,!n y w h ! great] m]it 9 re=m+ !m1 ,mrs4 ,b42 & aft] all ! wond]s t ,emily has relat$ to me1 ,i ?9k ,i /& b little *ance aga9/ y & y\r attractions4 ,mrs4 ,b4 ,y w1 ,i d\bt n1 advance a numb] ( objections2 b ^! ,i %all will+ly admit1 z !y w af=d an opportunity ( elucidat+ ! subject4 ,emily1 d y recollect ! names ( ! g5]al prop]ties ( bodies8 ,emily4 ,imp5etrability1 ext5sion1 figure1 divisibility1 in]tia & attraction4 ,mrs4 ,b4 ,v well4 ,y mu/ rememb] t ^! are prop]ties common to all bodies1 & ( :i* !y _c be depriv$2 all o!r prop]ties ( bodies are call$ accid5tal1 because !y dep5d on ! relation or connexion ( "o body to ano!r4 ,c>ol9e4 ,yet surely1 ,mrs4 ,b41 !re are o!r prop]ties :i* are ess5tial to bodies1 besides ^? y h enum]at$4 ,col\r & weight1 = in/ance1 are common to all bodies1 & d n arise f _! connexion ) ea* o!r1 b exi/ 9 ! bodies !mselves2 ^!1 !re=e1 _c be accid5tal qualities8 ,mrs4 ,b4 ,i beg y\r p>don2 ^! prop]ties d n exi/ 9 bodies indep5d5tly ( _! connexion ) o!r bodies4 ,c>ol9e4 ,:at6 h bodies no weight8 ,does n ?is table weigh heavi] ?an ?is book2 &1 if "o ?+ weighs heavi] ?an ano!r1 mu/ !re n be su* a ?+ z weight8 ,mrs4 ,b4 ,no d\bt3 b ?is prop]ty does n appe> to be ess5tial to bodies2 x dep5ds ^u _! connexion ) ea* o!r4 ,weight is an effect ( ! p[] ( attraction1 )\t :i* ! table & ! book w\ld h no weight :atev]4 ,emily4 ,i ?9k ,i und]/& y2 x is ! attraction ( gravity :i* makes bodies heavy4 ,mrs4 ,b4 ,y are "r4 ,i told y t ! attraction ( gravity 0 proportion$ to ! quantity ( matt] :i* bodies conta93 n[ ! e>? consi/+ ( a mu* great] quantity ( matt] ?an any body ^u its surface1 ! =ce ( its attraction mu/ necess>ily be greate/1 & mu/ draw e ?+ s situat$ t[>ds x2 9 consequ5ce ( :i*1 bodies t are unsupport$ fall to ! gr\nd1 :il/ ^? t are support$1 press ^u ! object :i* prev5ts _! fall1 ) a weight equal to ! =ce ) :i* !y gravitate t[>ds ! e>?4 ,c>ol9e4 ,! same cause !n :i* occasions ! fall ( bodies1 produces _! weight also4 ,x 0 v dull 9 me n to und]/& ?is be=e1 z x is ! natural & necess>y consequ5ce ( attraction2 b ! idea t bodies 7 n really heavy ( !mselves1 appe>$ to me q incompreh5sible4 ,b1 ,mrs4 ,b41 if attraction is a prop]ty ess5tial to matt]1 weight mu/ be s likewise2 = h[ c "o exi/ )\t ! o!r8 ,mrs4 ,b4 ,suppose !re 7 b "o body exi/+ 9 univ]sal space1 :at w\ld its weight be8 ,c>ol9e4 ,t w\ld dep5d ^u its size2 or m accurately speak+1 ^u ! quantity ( matt] x conta9$4 ,emily4 ,no1 no2 ! body w\ld h no weight1 :atev] 7 its size2 because no?+ w\ld attract x4 ,am ,i n "r1 ,mrs4 ,b48 ,mrs4 ,b4 ,y are3 y mu/ all[1 !re=e1 t x w\ld be possible = attraction to exi/ )\t weight2 = ea* ( ! p>ticles ( :i* ! body 0 compos$1 w\ld possess ! p[] ( attraction2 b !y c\ld ex]t x only among/ !mselves2 ! :ole mass hav+ no?+ to attract1 or to be attract$ by1 w\ld h no weight4 ,c>ol9e4 ,i am n[ well satisfi$ t weight is n ess5tial to ! exi/5ce ( bodies2 b :at h y to object to col\rs1 ,mrs4 ,b42 y w n1 ,i ?9k1 d5y t !y really exi/ 9 ! bodies !mselves4 ,mrs4 ,b4 ,:5 we come to treat ( ! subject ( col\rs1 ,i tru/ t ,i %all be able to conv9ce y1 t col\rs are likewise accid5tal qualities1 q di/9ct f ! bodies to :i* !y appe> to belong4 ,c>ol9e4 ,oh d pray expla9 x to u n[1 ,i am s v curi\s to "k h[ t is possible4 ,mrs4 ,b4 ,unless we proce$ ) "s degree ( ord] & me?od1 y w 9 ! end f9d y\rself b little ! wis] = all y le>n4 ,let u !re=e g on regul>ly1 & make ourselves well acqua9t$ ) ! g5]al prop]ties ( bodies be=e we proce$ fur!r4 ,emily4 ,to return1 !n1 to attraction1 7:i* appe>s to me by f> ! mo/ int]e/+ ( !m1 s9ce x belongs equally to all k9ds ( matt]17 x mu/ be mutual betwe5 two bodies2 & if s1 :5 a /one falls to ! e>?1 ! e>? %\ld rise "p ( ! way to meet ! /one8 ,mrs4 ,b4 ,c]ta9ly2 b y mu/ recollect t ! =ce ( attraction is proportion$ to ! quantity ( matt] :i* bodies conta91 & if y consid] ! diff]5ce !re is 9 t respect1 betwe5 a /one & ! e>?1 y w n be surpris$ t y d n p]ceive ! e>? rise to meet ! /one2 = ?\gh x is true t a mutual attraction takes place betwe5 ! e>? & ! /one1 t ( ! latt] is s v small 9 comp>ison to t ( ! =m]1 z to r5d] its effect ins5sible4 ,emily4 ,b s9ce attraction is proportion$ to ! quantity ( matt] :i* bodies conta91 :y d n ! hills attract ! h\ses & *ur*es t[>ds !m8 ,c>ol9e4 ,:at an idea1 ,emily6 ,h[ c ! h\ses & *ur*es be mov$1 :5 !y are s firmly fix$ 9 ! gr\nd6 ,mrs4 ,b4 ,emily's "q is n absurd1 & y\r answ]1 ,c>ol9e1 is p]fectly j2 b c y tell u :y ! h\ses & *ur*es are s firmly fix$ 9 ! gr\nd8 ,c>ol9e4 ,i am afraid ,i h answ]$ "r by m]e *ance2 = ,i beg9 to suspect t bricklay]s & c>p5t]s c\ld give b little /ability to _! build+s1 )\t ! aid ( attraction4 ,mrs4 ,b4 ,x is c]ta9ly ! cohesive attraction betwe5 ! bricks & ! mort>1 :i* enables !m to build walls1 & ^! are s /rongly attract$ by ! e>?1 z to resi/ e o!r impulse2 o!rwise !y w\ld necess>ily move t[>ds ! hills & ! m\nta9s2 b ! less] =ce mu/ yield to ! great]4 ,!re are1 h[ev]1 "s circum/ances 9 :i* ! attraction ( a l>ge body has s5sibly c\nt]act$ t ( ! e>?4 ,if :il/ /&+ on ! declivity ( a m\nta91 y hold a plumb-l9e 9 y\r h&1 ! weight w n fall p]p5dicul> to ! e>?1 b incl9e a little t[>ds ! m\nta92 & ?is is ow+ to ! lat]al1 or sideways attraction ( ! m\nta91 int]f]+ ) ! p]p5dicul> attraction ( ! e>?4 ,emily4 ,b ! size ( a m\nta9 is v trifl+1 comp>$ to ! :ole e>?4 ,mrs4 ,b4 ,attraction1 y mu/ recollect1 is 9 proportion to ! quantity ( matt]1 & al?\gh t ( ! m\nta91 is mu* less ?an t ( ! e>?1 x may yet be suffici5t to act s5sibly ^u ! plumb-l9e :i* is s ne> to x4 ,c>ol9e4 ,pray1 ,mrs4 ,b41 d ! two scales ( a balance hang p>allel to ea* o!r8 ,mrs4 ,b4 ,y mean1 ,i suppose1 9 o!r words to inquire :e!r two l9es :i* are p]p5dicul> to ! e>?1 are p>allel to ea* o!r8 ,i believe ,i guess ! reason ( y\r "q2 b ,i wi% y w\ld endeav\r to answ] x )\t my assi/ance4 ,c>ol9e4 ,i 0 ?9k+ t su* l9es mu/ bo? t5d by gravity to ! same po9t1 ! c5tre ( ! e>?2 n[ l9es t5d+ to ! same po9t _c be p>allel1 z p>allel l9es are always at an equal di/ance f ea* o!r1 & w\ld nev] meet4 ,mrs4 ,b4 ,v well expla9$2 y see n[ ! use ( y\r k ( p>allel l9es3 _h y be5 ignorant ( _! prop]ties1 y c\ld n h drawn su* a conclusion4 ,?is may enable y to =m an idea ( ! great advantage to be d]iv$ ev5 f a slight k ( geometry1 9 ! /udy ( natural philosophy2 & if aft] ,i h made y acqua9t$ ) ! fir/ elem5ts1 y %\ld be tempt$ to pursue ! /udy1 ,i w\ld advise y to prep>e y\rselves by acquir+ "s k ( geometry4 ,?is sci5ce w\ld tea* y t l9es :i* fall p]p5dicul> to ! surface ( a sph]e _c be p>allel1 because !y w\ld all meet1 if prolong$ to ! c5tre ( ! sph]e2 :ile l9es t fall p]p5dicul> to a plane or flat surface1 are always p>allel1 because if prolong$1 !y w\ld nev] meet4 ,emily4 ,& yet a pair ( scales1 hang+ p]p5dicul> to ! e>?1 appe> p>allel8 ,mrs4 ,b4 ,because ! sph]e is s l>ge1 & ! scales consequ5tly conv]ge s little1 t _! incl9ation is n p]ceptible to our s5ses2 if we c\ld con/ruct a pair ( scales ^: beam w\ld ext5d sev]al degrees1 _! conv]g5ce w\ld be v obvi\s2 b z ?is _c be accompli%$1 let u draw a small figure ( ! e>?1 & !n we may make a pair ( scales ( ! proportion we please4 7fig4 #a4 pl4 ,i47 ,c>ol9e4 ,?is figure r5d]s x v cle>3 !n two bodies _c fall to ! e>? 9 p>allel l9es8 ,mrs4 ,b4 ,nev]4 ,c>ol9e4 ,! reason t a heavy body falls quick] ?an a light "o1 is1 ,i suppose1 because ! e>? attracts x m /rongly4 ,mrs4 ,b4 ,! e>?1 x is true1 attracts a heavy body m ?an a light "o2 b t w\ld n make ! "o fall quick] ?an ! o!r4 ,c>ol9e4 ,yet1 s9ce x is attraction t occasions ! fall ( bodies1 surely ! m a body is attract$1 ! m rapidly x w fall4 ,besides1 exp]i5ce proves x to be s4 ,d we n e day see heavy bodies fall quickly1 & light bodies sl[ly8 ,emily4 ,x /rikes me1 z x does ,c>ol9e1 t z attraction is proportion$ to ! quantity ( matt]1 ! e>? mu/ necess>ily attract a body :i* conta9s a great quantity m /rongly1 & !re=e br+ x to ! gr\nd soon] ?an "o consi/+ ( a small] quantity4 ,mrs4 ,b4 ,y mu/ consid]1 t if heavy bodies are attract$ m /rongly ?an light ones1 !y require m attraction to make !m fall4 ,rememb] t bodies h no natural t5d5cy to fall1 any m ?an to rise1 or to move lat]ally1 & t !y w n fall unless impell$ by "s =ce2 n[ ?is =ce mu/ be proportion$ to ! quantity ( matt] x has to move3 a body consi/+ ( #ajjj p>ticles ( matt]1 = in/ance1 requires t5 times z mu* attraction to br+ x to ! gr\nd 9 ! same space ( "t z a body consi/+ ( only #ajj p>ticles4 ,illu/ration3 ,,plate ,i4 ,c>ol9e4 ,i d n und]/& t2 = x seems to me1 t ! heavi] a body is1 ! move easily & readily x falls4 ,emily4 ,i ?9k ,i n[ compreh5d x2 let me try if ,i c expla9 x to ,c>ol9e4 ,suppose t ,i draw t[>ds me two weighty bodies1 ! "o ( #ajj lbs4 ! o!r ( #ajjj lbs4 mu/ ,i n ex]t t5 times z mu* /r5g? to draw ! l>g] "o to me1 9 ! same space ( "t1 z is requir$ = ! small] "o8 ,& if ! e>? draws a body ( #ajjj lbs4 weight to x 9 ! same space ( "t t x draws a body ( #ajj lbs4 does x n foll[ t x attracts ! body ( #ajjj lbs4 weight ) t5 times ! =ce t x does t ( #ajj lbs48 ,c>ol9e4 ,i compreh5d y\r reason+ p]fectly2 b if x 7 s1 ! body ( #ajjj lbs4 weight1 & t ( #ajj lbs4 w\ld fall ) ! same rapidity2 & ! consequ5ce w\ld be1 t all bodies1 :e!r light or heavy1 be+ at an equal di/ance f ! gr\nd1 w\ld fall to x 9 ! same space ( "t3 n[ x is v evid5t t ?is conclusion is absurd2 exp]i5ce e in/ant contradicts x2 obs]ve h[ mu* soon] ?is book rea*es ! floor ?an ?is %eet ( pap]1 :5 ,i let !m drop toge!r4 ,emily4 ,t is an objection ,i _c answ]4 ,i mu/ ref] x to y1 ,mrs4 ,b4 ,mrs4 ,b4 ,i tru/ t we %all n f9d x insurm\ntable4 ,x is true t1 accord+ to ! laws ( attraction1 all bodies at an equal di/ance f ! e>?1 %\ld fall to x 9 ! same space ( "t2 & ?is w\ld actually take place if no ob/acle int]v5$ to imp$e _! fall4 ,b bodies fall ?r\gh ! air1 & x is ! resi/ance ( ! air :i* makes bodies ( diff]5t d5sity fall ) diff]5t degrees ( velocity4 ,!y mu/ all =ce _! way ?r\gh ! air1 b d5se heavy bodies ov]come ?is ob/acle m easily ?an r>] or light] ones2 because 9 ! same space !y conta9 m gravitat+ p>ticles4 ,! resi/ance :i* ! air opposes to ! fall ( bodies is proportion$ to _! surface1 n to _! weight2 ! air be+ in]t1 _c ex]t a great] =ce to support ! weight ( a cannon ball1 ?an x does to support ! weight ( a ball 7( ! same size7 made ( lea!r2 b ! cannon ball w ov]come ?is resi/ance m easily1 & fall to ! gr\nd1 consequ5tly1 quick] ?an ! lea!r ball4 ,c>ol9e4 ,?is is v cle> & solves ! difficulty p]fectly4 ,! air (f]s ! same resi/ance to a bit ( lead & a bit ( fea!r ( ! same size2 yet ! "o seems to meet ) no ob/ruction 9 its fall1 :il/ ! o!r is evid5tly resi/$ & support$ = "s "t by ! air4 ,emily4 ,! l>g] ! surface ( a body1 !n1 ! m air x cov]s1 & ! great] is ! resi/ance x meets ) f x4 ,mrs4 ,b4 ,c]ta9ly3 obs]ve ! mann] 9 :i* ?is %eet ( pap] falls2 x floats a:ile 9 ! air1 & !n g5tly desc5ds to ! gr\nd4 ,i w roll ! same piece ( pap] up into a ball3 x (f]s n[ b a small surface to ! air1 & enc\nt]s !re=e b little resi/ance3 see h[ mu* m rapidly x falls4 ,! heavie/ bodies may be made to float a:ile 9 ! air1 by mak+ ! ext5t ( _! surface c\nt]balance _! weight4 ,"h is "s gold1 :i* is "o ( ! mo/ d5se bodies we are acqua9t$ )2 b x has be5 beat5 into a v ?9 leaf1 & (f]s s great an ext5t ( surface 9 proportion to its weight1 t its fall1 y see1 is /ill m ret>d$ by ! resi/ance ( ! air1 ?an t ( ! %eet ( pap]4 ,c>ol9e4 ,t is v curi\s3 & x is1 ,i suppose1 ^u ! same pr9ciple t a ?9 slate s9ks 9 wat] m sl[ly ?an a r\nd /one4 ,b1 ,mrs4 ,b41 if ! air is a real body1 is x n also subject$ to ! laws ( gravity8 ,mrs4 ,b4 ,und\bt$ly4 ,c>ol9e4 ,!n :y does x n1 l all o!r bodies1 fall to ! gr\nd8 ,mrs4 ,b4 ,on acc\nt ( its spr+ or ela/icity4 ,! air is an ela/ic fluid2 & ! peculi> prop]ty ( ela/ic bodies is to resume1 aft] compression1 _! orig9al dim5sions2 & y mu/ consid] ! air ( :i* ! atmosph]e is compos$ z exi/+ 9 a /ate ( compression1 = its p>ticles be+ drawn t[>ds ! e>? by gravity1 are br\ght clos] toge!r ?an !y w\ld o!rwise be1 b ! spr+ or ela/icity ( ! air by :i* x endeav\rs to resi/ compression1 gives x a con/ant t5d5cy to exp& itself1 s z to resume ! dim5sions x w\ld naturally h1 if n "u ! influ5ce ( gravity4 ,! air may !re=e be said con/antly to /ruggle ) ! p[] ( gravity )\t be+ able to ov]come x4 ,gravity ?us conf9es ! air to ! regions ( our globe1 :il/ its ela/icity prev5ts x f fall+1 l o!r bodies1 to ! gr\nd4 ,emily4 ,! air !n is1 ,i suppose1 ?ick]1 or ,i %\ld r say m d5se1 ne> ! surface ( ! e>?1 ?an 9 ! high] regions ( ! atmosph]e2 = t "p ( ! air :i* is ne>] ! surface ( ! e>? mu/ be mo/ /rongly attract$4 ,mrs4 ,b4 ,! dim9ution ( ! =ce ( gravity1 at s small a di/ance z t to :i* ! atmosph]e ext5ds 7comp>$ ) ! size ( ! e>?7 is s inconsid]able z to be sc>cely s5sible2 b ! pressure ( ! upp] p>ts ( ! atmosph]e on ^? b5ea?1 r5d]s ! air ne> ! surface ( ! e>? mu* m d5se ?an 9 ! upp] regions4 ,! pressure ( ! atmosph]e has be5 comp>$ to t ( a pile ( fleeces ( wool1 9 :i* ! l[] fleeces are press$ toge!r by ! weight ( ^? above2 ^! lie light & loose1 9 proportion z !y approa* ! upp]mo/ fleece1 :i* receives no ext]nal pressure1 & is conf9$ m]ely by ! =ce ( its own gravity4 ,emily4 ,i d n und]/& h[ x is t ! air c be spr+y or ela/ic1 z ! p>ticles ( :i* x is compos$ mu/1 accord+ to ! g5]al law1 attract ea* o!r2 yet _! ela/icity1 mu/ arise f a t5d5cy to rec$e f ea* o!r4 ,mrs4 ,b4 ,h y =gott5 :at ,i told y respect+ ! effects ( heat1 a fluid s subtile t x readily p]vades all sub/ances1 & ev5 9 solid bodies1 c\nt]acts ! attraction ( cohesion8 ,9 air ! quantity ( heat int]pos$ is s great1 z to cause its p>ticles actually to repel ea* o!r1 & x is to ?is t we mu/ ascribe its ela/icity2 ?is1 h[ev]1 does n prev5t ! e>? f ex]t+ its attraction ^u ! individual p>ticles ( :i* x consi/s4 ,c>ol9e4 ,x has j occurr$ to me t !re are "s bodies :i* d n gravitate t[>ds ! e>?4 ,smoke & /eam1 = in/ance1 rise in/ead ( fall+4 ,mrs4 ,b4 ,x is /ill gravity :i* produces _! asc5t2 at lea/1 7 t p[] de/roy$1 ^! bodies w\ld n rise4 ,c>ol9e4 ,i %all be out ( conceit ) gravity1 if x is s inconsi/5t 9 its op]ations4 ,mrs4 ,b4 ,!re is no difficulty 9 reconcil+ ?is app>5t inconsi/5cy ( effect4 ,! air ne> ! e>? is heavi] ?an smoke1 /eam1 or o!r vap\rs2 x consequ5tly n only supports ^! light bodies1 b =ces !m to rise1 till !y rea* a "p ( ! atmosph]e1 ! weight ( :i* is n great] ?an _! own1 & !n !y rema9 /ation>y4 ,look at ?is bason ( wat]2 :y does ! piece ( pap] :i* ,i ?r[ into x float on ! surface8 ,emily4 ,because1 be+ light] ?an ! wat]1 x is support$ by x4 ,mrs4 ,b4 ,& n[ t ,i p\r m wat] into ! bason1 :y does ! pap] rise8 ,emily4 ,! wat] be+ heavi] ?an ! pap]1 gets b5ea? x1 & obliges x to rise4 ,mrs4 ,b4 ,9 a simil> mann] are smoke & vap\r =c$ upw>ds by ! air2 b ^! bodies d n1 l ! pap]1 asc5d to ! surface ( ! fluid1 because1 z we obs]v$ be=e1 ! air be+ less d5se1 & consequ5tly light] z x is m di/ant f ! e>?1 vap\rs rise only till !y atta9 a region ( air ( _! own d5sity4 ,smoke1 inde$ asc5ds b a v little way2 x consi/s ( m9ute p>ticles ( fuel1 c>ri$ up by a curr5t ( heat$ air1 f ! fire bel[3 heat1 y recollect1 exp&s all bodies2 x consequ5tly r>efies air1 & r5d]s x light] ?an ! cold] air ( ! atmosph]e2 ! heat$ air f ! fire c>ries up ) x vap\r & small p>ticles ( ! combu/ible mat]ials :i* are burn+ 9 ! fire4 ,:5 ?is curr5t ( hot air is cool$ by mix+ ) ! atmosph]e1 ! m9ute p>ticles ( coal1 or o!r combu/ible1 fall2 x is ?is :i* produces ! small black flakes :i* r5d] ! air1 & e ?+ 9 contact ) x1 9 ,london1 s dirty4 ,c>ol9e4 ,y mu/1 h[ev]1 all[ me to make "o m objection to ! univ]sal gravity ( bodies2 :i* is ! asc5t ( air balloons1 ! mat]ials ( :i* are und\bt$ly heavi] ?an air3 h[1 !re=e1 c !y be support$ by x8 ,mrs4 ,b4 ,i admit t ! mat]ials ( :i* balloons are made are heavi] ?an ! air2 b ! air ) :i* !y are fill$ is an ela/ic fluid1 ( a diff]5t nature f atmosph]ic air1 & consid]ably light]2 s t on ! :ole ! balloon is light] ?an ! air :i* x displaces1 & consequ5tly w rise1 on ! same pr9ciple z smoke & vap\r4 ,n[1 ,emily1 let me he> if y c expla9 h[ ! gravity ( bodies is modifi$ by ! effect ( ! air8 ,emily4 ,! air =ces bodies :i* are light] ?an itself to asc5d2 ^? t are ( an equal weight w rema9 /ation>y 9 x2 & ^? t are heavi] w desc5d ?r\gh x3 b ! air w h "s effect on ^! la/2 = if !y are n mu* heavi]1 !y w ) difficulty ov]come ! resi/ance !y meet ) 9 pass+ ?r\gh x1 !y w be borne up by x1 & _! fall w be m or less ret>d$4 ,mrs4 ,b4 ,v well4 ,obs]ve h[ sl[ly ?is light fea!r falls to ! gr\nd1 :ile a heavi] body1 l ?is m>ble1 ov]comes ! resi/ance :i* ! air makes to its desc5t mu* m easily1 & its fall is proportionally m rapid4 ,i n[ ?r[ a pebble into ?is tub ( wat]2 x does n rea* ! bottom ne> s soon z if !re 7 no wat] 9 ! tub1 because x meets ) resi/ance f ! wat]4 ,suppose t we c\ld empty ! tub1 n only ( wat]1 b ( air also1 ! pebble w\ld !n fall quick] /ill1 z x w\ld 9 t case meet ) no resi/ance at all to c\nt]act its gravity4 ,?us y see t x is n ! diff]5t degrees ( gravity1 b ! resi/ance ( ! air1 :i* prev5ts bodies ( diff]5t weight f fall+ ) equal velocities2 if ! air did n be> up ! fea!r1 x w\ld rea* ! gr\nd z soon z ! m>ble4 ,c>ol9e4 ,i make no d\bt t x is s2 & yet ,i d n feel q satisfi$4 ,i wi% !re 0 any place void ( air1 9 :i* ! exp]im5t c\ld be made4 ,mrs4 ,b4 ,if t pro( w satisfy y\r d\bts1 ,i c give x y4 ,"h is a ma*9e call$ an air pump1 7fig4 #b4 pl4 #a47 by means ( :i* ! air may be expell$ f any close vessel :i* is plac$ ov] ?is op5+1 ?r\gh :i* ! air is pump$ out4 ,glasses ( v>i\s %apes1 usually call$ receiv]s1 are employ$ = ?is purpose4 ,we %all n[ exhau/ ! air f ?is tall receiv] :i* is plac$ ov] ! op5+1 & we %all f9d t bodies )9 x1 :atev] _! weight or size1 w fall f ! top to ! bottom 9 ! same space ( "t4 ,c>ol9e4 ,oh1 ,i %all be delight$ ) ?is exp]im5t2 :at a curi\s ma*9e6 h[ c y put ! two bodies ( diff]5t weight )9 ! glass1 )\t admitt+ ! air8 ,mrs4 ,b4 ,a gu9ea & a fea!r are already plac$ !re = ! purpose ( ! exp]im5t3 "h is1 y see1 a contrivance to fa/5 !m 9 ! upp] "p ( ! glass2 z soon z ! air is pump$ out1 ,i %all turn ?is little screw1 by :i* means ! brass plates :i* support !m w be remov$1 & ! two bodies w fall4--,n[ ,i believe ,i h pretty well exhau/$ ! air4 ,c>ol9e4 ,pray let me turn ! screw4--,i decl>e1 !y bo? rea*$ ! bottom at ! same in/ant6 ,did y see1 ,emily1 ! fea!r appe>$ z heavy z ! gu9ea8 ,emily4 ,exactly2 & fell j z quickly4 ,h[ wond]ful ?is is6 :at a numb] ( ent]ta9+ exp]im5ts might be made ) ?is ma*9e6 ,mrs4 ,b4 ,no d\bt !re are a great _m2 b we %all res]ve !m to elucidate ! subjects to :i* !y relate3 if ,i _h n expla9$ to y :y ! gu9ea1 & ! fea!r fell ) equal velocity1 y w\ld n h be5 s well pleas$ ) ! exp]im5t4 ,emily4 ,i %\ld h be5 z mu* surpris$1 b n s mu* int]e/$2 besides1 exp]im5ts help to impr9t on ! memory ! facts !y are int5d$ to illu/rate2 x w be bett] !re=e = u to re/ra9 our curiosity1 & wait = o!r exp]im5ts 9 _! prop] places4 ,c>ol9e4 ,pray by :at means is ?is receiv] exhau/$ ( its air8 ,mrs4 ,b4 ,y mu/ le>n some?+ ( me*anics 9 ord] to und]/& ! con/ruction ( a pump4 ,at our next meet+1 !re=e1 ,i %all endeav\r to make y acqua9t$ ) ! laws ( motion1 z an introduction to t subject4 ,que/ions #a4 7,pg4 #bb7 ,:at are ^? prop]ties ( bodies call$1 :i* are n common to all8 #b4 7,pg4 #bc7 ,:y are !y s call$8 #c4 7,pg4 #bc7 ,:at is ! cause ( weight 9 bodies8 #d4 7,pg4 #bc7 ,:at is ! reason t all bodies ne> to ! surface ( ! e>?1 are drawn t[>ds x8 #e4 7,pg4 #bd7 ,if attraction is ! cause ( weight1 c\ld y suppose x possible = a body to possess ! =m] & n ! latt] prop]ty8 #f4 7,pg4 #bd7 ,:5 a /one falls to ! gr\nd1 9 :i* ( ! two bodies does ! p[] ( attraction exi/8 #g4 7,pg4 #bd7 ,if ! attraction be mutual1 :y does n ! e>? approa* ! /one1 z mu* z ! /one approa*es ! e>?8 #h4 7,pg4 #bd7 ,if attraction be 9 proportion to ! mass1 :y does n a hill1 draw t[>ds itself1 a h\se plac$ ne> x8 #i4 7,pg4 #be7 ,h[ c ! attraction ( a m\nta9 be r5d]$ s5sible8 #aj4 7,pg4 #be7 ,:y _c two l9es :i* are p]p5dicul> to ! surface ( ! e>? be p>allel to ea* o!r8 #aa4 7,pg4 #bf7 ,draw a small figure ( ! e>? to exemplify ?is1 z 9 fig4 #a4 plate #a4 #ab4 7,pg4 #bg7 ,if bodies 7 n resi/$ by ! air1 ^? :i* are light1 w\ld fall z quickly z ^? :i* are heavy1 h[ c y acc\nt = ?is8 #ac4 7,pg4 #bg7 ,:at !n is ! reason t a book1 & a %eet ( pap]1 let fall f ! same height1 w n rea* ! gr\nd 9 ! same "t8 #ad4 7,pg4 #bh7 ,:at !n w be ! effect ( increas+ ! surface ( a body8 #ae4 7,pg4 #bh7 ,:at c\ld y d to a %eet ( pap]1 to make x fall quickly1 & :y8 #af4 7,pg4 #bh7 ,in=m me h[ a v d5se body may be made to float 9 ! air8 #ag4 7,pg4 #bh7 ,! air is a real body1 :y does x n fall to ! gr\nd8 #ah4 7,pg4 #bi7 ,! air is m d5se ne> ! surface ( ! e>?1 & decreases 9 d5sity z y asc5d1 h[ is ?is acc\nt$ =1 & to :at is x comp>$8 #ai4 7,pg4 #bi7 ,:at is x :i* causes ! p>ticles ( air to rec$e f ea* o!r1 & seems to de/roy _! mutual attraction8 #bj4 7,pg4 #bi7 ,smoke & vap\r asc5d 9 ! atmosph]e1 h[ c y reconcile ?is ) gravitation8 #ba4 7,pg4 #cj7 ,h[ w\ld y illu/rate ?is by ! float+ ( a piece ( pap] on wat]8 #bb4 7,pg4 #cj7 ,does smoke rise to a great height 9 ! air1 & if n1 :at prev5ts its s do+8 #bc4 7,pg4 #cj7 ,:at limits ! height to :i* vap\rs rise8 #bd4 7,pg4 #cj7 ,( :at does smoke consi/8 #be4 7,pg4 #cj7 ,air balloons are =m$ ( heavy mat]ials1 h[ w y acc\nt = _! ris+ 9 ! air8 #bf4 7,pg4 #cj7 ,:at influ5ce does ! air ex]t1 on bodies less d5se ?an itself1 on ^? ( equal1 & on ^? ( great] d5sity8 #bg4 7,pg4 #ca7 ,if ! air c\ld be entirely remov$1 :at influ5ce w\ld ?is h ^u ! fall+ ( heavy & light bodies8 #bh4 7,pg4 #ca7 ,h[ c\ld ?is be exemplifi$ by means ( ! air pump8 ,,conv]sation ,,iii4 ,,on ,,! ,,laws ,,( ,,motion4 ,,( ,,motion4 ,,( ,,! ,,in]tia ,,( ,,bodies4 ,,( ,,=ce ,,to ,,produce ,,motion4 ,,direction ,,( ,,motion4 ,,velocity1 ,,absolute ,,& ,,relative4 ,,uni=m ,,motion4 ,,ret>d$ ,,motion4 ,,accel]at$ ,,motion4 ,,velocity ,,( ,,fall+ ,,bodies4 ,,mom5tum4 ,,action ,,& ,,reaction ,,equal4 ,,ela/icity ,,( ,,bodies4 ,,porosity ,,( ,,bodies4 ,,reflect$ ,,motion4 ,,angles ,,( ,,incid5ce ,,& ,,reflection4 ,,mrs4 ,b4 ,! sci5ce ( me*anics is f\nd$ on ! laws ( motion2 x w !re=e be necess>y to make y acqua9t$ ) ^! laws be=e we exam9e ! me*anical p[]s4 ,tell me1 ,c>ol9e1 :at d y und]/& by ! ^w motion8 ,c>ol9e4 ,i ?9k ,i und]/& x p]fectly1 ?\gh ,i am at a loss to describe x4 ,motion is ! act ( mov+ ab\t1 ( go+ f "o place to ano!r1 x is ! contr>y ( rema9+ at re/4 ,mrs4 ,b4 ,v well4 ,motion !n consi/s 9 a *ange ( place2 a body is 9 motion :5ev] x is *ang+ its situation ) reg>d to a fix$ po9t4 ,n[ s9ce we h obs]v$ t "o ( ! g5]al prop]ties ( bodies is in]tia1 t is1 an entire passiv5ess1 ei!r ) reg>d to motion or re/1 x foll[s t a body _c move )\t be+ put into motion2 ! p[] :i* puts a body into motion is call$ =ce2 ?us ! /roke ( ! hamm] is ! =ce :i* drives ! nail2 ! pull+ ( ! horse t :i* draws ! c>riage1 c4 ,=ce !n is ! cause :i* produces motion4 ,emily4 ,& may we n say t gravity is ! =ce :i* occasions ! fall ( bodies8 ,mrs4 ,b4 ,und\bt$ly4 ,i h giv5 y ! mo/ famili> illu/rations 9 ord] to r5d] ! explanation cle>2 b s9ce y seek = m sci5tific examples1 y may say t cohesion is ! =ce :i* b9ds ! p>ticles ( bodies toge!r1 & heat t :i* drives !m asund]4 ,! motion ( a body act$ ^u by a s+le =ce1 is always 9 a /raight l9e1 & 9 ! direction 9 :i* x receiv$ ! impulse4 ,c>ol9e4 ,t is v natural2 = z ! body is in]t1 & c move only because x is impell$1 x w move only 9 ! direction 9 :i* x is impell$4 ,! degree ( quickness ) :i* x moves1 mu/1 ,i suppose1 also dep5d ^u ! degree ( =ce ) :i* x is impell$4 ,mrs4 ,b4 ,yes2 ! rate at :i* a body moves1 or ! %ortness ( ! "t :i* x takes to move f "o place to ano!r1 is call$ its velocity2 & x is "o ( ! laws ( motion1 t ! velocity ( ! mov+ body is proportional to ! =ce by :i* x is put 9 motion4 ,we mu/ di/+ui% betwe5 absolute & relative velocity4 ,! velocity ( a body is call$ absolute1 if we consid] ! motion ( ! body 9 space1 )\t any ref]5ce to t ( o!r bodies4 ,:51 = in/ance1 a horse goes fifty miles 9 t5 h\rs1 8 velocity is five miles an h\r4 ,! velocity ( a body is t]m$ relative1 :5 comp>$ ) t ( ano!r body :i* is itself 9 motion4 ,= in/ance1 if "o man walks at ! rate ( a mile an h\r1 & ano!r at ! rate ( two miles an h\r1 ! relative velocity ( ! latt] is d\ble t ( ! =m]2 b ! absolute velocity ( ! "o is "o mile1 & t ( ! o!r two miles an h\r4 ,emily4 ,let me see if ,i und]/& x--,! relative velocity ( a body is ! degree ( rapidity ( its motion comp>$ ) t ( ano!r body2 ?us if "o %ip sail ?ree times z f> z ano!r %ip 9 ! same space ( "t1 ! velocity ( ! =m] is equal to ?ree times t ( ! latt]4 ,mrs4 ,b4 ,! g5]al rule may be express$ ?us3 ! velocity ( a body is measur$ by ! space ov] :i* x moves1 divid$ by ! "t :i* x employs 9 t motion3 ?us if y travel "o hundr$ miles 9 tw5ty h\rs1 :at is y\r velocity 9 ea* h\r8 ,emily4 ,i mu/ divide ! space1 :i* is "o hundr$ miles1 by ! "t1 :i* is tw5ty h\rs1 & ! answ] w be five miles an h\r4 ,!n1 ,mrs4 ,b41 may we n rev]se ?is rule1 & say t ! "t is equal to ! space divid$ by ! velocity2 s9ce ! space1 "o hundr$ miles1 divid$ by ! velocity1 five miles p] h\r1 gives tw5ty h\rs = ! "t8 ,mrs4 ,b4 ,c]ta9ly2 & we may say also t ! space is equal to ! velocity multipli$ by ! "t4 ,c y tell me1 ,c>ol9e1 h[ _m miles y w h travell$1 if y\r velocity is ?ree miles an h\r1 & y travel six h\rs8 ,c>ol9e4 ,eighte5 miles2 = ! product ( #c multipli$ by #f1 is #ah4 ,mrs4 ,b4 ,i suppose t y und]/& :at is meant by ! t]ms uni=m1 accel]at$ & ret>d$ motion4 ,emily4 ,i conceive uni=m motion to be t ( a body ^: motion is regul>1 & at an equal rate ?r\gh\t2 = in/ance a horse t goes an equal numb] ( miles e h\r4 ,b ! h& ( a wat* is a mu* bett] example1 z its motion is s regul> z to indicate ! "t4 ,mrs4 ,b4 ,y h a "r idea ( uni=m motion2 b x w\ld be m correctly express$ by say+1 t ! motion ( a body is uni=m :5 x passes ov] equal spaces 9 equal times4 ,uni=m motion is produc$ by a =ce hav+ act$ on a body once & hav+ ceas$ to act2 z1 = in/ance1 ! /roke ( a bat on a ball4 ,c>ol9e4 ,b ! motion ( a ball is n uni=m2 its velocity gradually dim9i%es till x falls to ! gr\nd4 ,mrs4 ,b4 ,recollect t ! ball is in]t1 & has no m p[] to /op1 ?an to put itself 9 motion2 if x falls1 !re=e1 x mu/ be /opp$ by "s =ce sup]ior to t by :i* x 0 project$1 & :i* de/roys its motion4 ,c>ol9e4 ,& x is no d\bt ! =ce ( gravity :i* c\nt]acts & de/roys t ( projection2 b if !re 7 no su* p[] z gravity1 w\ld ! ball nev] /op8 ,mrs4 ,b4 ,if nei!r gravity nor any o!r =ce1 su* z ! resi/ance ( ! air1 oppos$ its motion1 ! ball1 or ev5 a /one ?r[n by ! h&1 w\ld proce$ onw>ds 9 a "r l9e1 & ) a uni=m velocity = ev]4 ,c>ol9e4 ,y a/oni% me6 ,i ?\ght t x 0 impossible to produce p]petual motion8 ,mrs4 ,b4 ,p]petual motion _c be produc$ by art1 because gravity ultimately de/roys all motion t human p[] c produce4 ,emily4 ,b indep5d5tly ( ! =ce ( gravity1 ,i _c conceive t ! little motion ,i am capable ( giv+ to a /one w\ld put x 9 motion = ev]4 ,mrs4 ,b4 ,! quantity ( motion y communicate to ! /one w\ld n influ5ce its duration2 if y ?rew x ) little =ce x w\ld move sl[ly1 = its velocity y mu/ rememb]1 w be proportional to ! =ce ) :i* x is project$2 b if !re is no?+ to ob/ruct its passage1 x w cont9ue to move ) ! same velocity1 & 9 ! same direction z :5 y fir/ project$ x4 ,c>ol9e4 ,?is appe>s to me q incompreh5sible2 we d n meet ) a s+le in/ance ( x 9 nature4 ,mrs4 ,b4 ,i beg y\r p>don4 ,:5 y come to /udy ! motion ( ! cele/ial bodies1 y w f9d t nature ab\nds ) examples ( p]petual motion2 & t x conduces z mu* to ! h>mony ( ! sy/em ( ! univ]se1 z ! preval5ce ( x on ! surface ( ! e>?1 w\ld to ! de/ruction ( all our com=ts4 ,! wisdom ( ,provid5ce has !re=e orda9$ insurm\ntable ob/acles to p]petual motion "h bel[2 & ?\gh ^! ob/acles (t5 compel u to cont5d ) great difficulties1 yet ^! appe> necess>y to t ord]1 regul>ity & repose1 s ess5tial to ! pres]vation ( all ! v>i\s be+s ( :i* ?is _w is compos$4 ,n[ c y tell me :at is ret>d$ motion8 ,c>ol9e4 ,ret>d$ motion is t ( a body :i* moves e mom5t sl[] & sl[]3 ?us :5 ,i am tir$ ) walk+ fa/1 ,i slack5 my pace2 or :5 a /one is ?r[n upw>ds1 its velocity is gradually dim9i%$ by ! p[] ( gravity4 ,mrs4 ,b4 ,ret>d$ motion is produc$ by "s =ce act+ ^u ! body 9 a direction opposite to t :i* fir/ put x 9 motion3 y :o are an animat$ be+1 end[$ ) p[] & w1 may slack5 y\r pace1 or /op to re/ :5 y are tir$2 b in]t matt] is incapable ( any feel+ ( fatigue1 c nev] slack5 its pace1 & nev] /op1 unless ret>d$ or arre/$ 9 its c\rse by "s oppos+ =ce2 & z x is ! laws ( in]t bodies ( :i* me*anical philosophy treats1 ,i pref] y\r illu/ration ( ! /one ret>d$ 9 its asc5t4 ,n[ ,emily1 x is y\r turn2 :at is accel]at$ motion8 ,emily4 ,accel]at$ motion1 ,i suppose1 takes place :5 ! velocity ( a body is increas$2 if y _h n object$ to our giv+ su* active bodies z ourselves z examples1 ,i %\ld say t my motion is accel]at$ if ,i *ange my pace f walk+ to runn+4 ,i _c ?9k ( any in/ance ( accel]at$ motion 9 inanimate bodies2 all motion ( in]t matt] seems to be ret>d$ by gravity4 ,mrs4 ,b4 ,n 9 all cases2 = ! p[] ( gravitation sometimes produces accel]at$ motion2 = in/ance1 a /one fall+ f a height1 moves ) a regul>ly accel]at$ motion4 ,emily4 ,true2 because ! ne>] x approa*es ! e>?1 ! m x is attract$ by x4 ,mrs4 ,b4 ,y h mi/ak5 ! cause ( its accel]at$ motion2 = ?\gh x is true t ! =ce ( gravity increases z a body approa*es ! e>?1 ! diff]5ce is s trifl+ at any small di/ance f its surface1 z n to be p]ceptible4 ,accel]at$ motion is produc$ :5 ! =ce :i* put a body 9 motion1 cont9ues to act ^u x dur+ its motion1 s t its velocity is cont9ually increas$4 ,:5 a /one falls f a height1 ! impulse :i* x receives f gravitation 9 ! fir/ in/ant ( its fall1 w\ld be suffici5t to br+ x to ! gr\nd ) a uni=m velocity3 =1 z we h obs]v$1 a body hav+ be5 once act$ ^u by a =ce1 w cont9ue to move ) a uni=m velocity2 b ! /one is n act$ ^u by gravity m]ely at ! fir/ in/ant ( its fall2 ?is p[] cont9ues to impel x dur+ ! :ole "t ( its desc5t1 & x is ?is cont9u$ impulse :i* accel]ates its motion4 ,emily4 ,i d n q und]/& t4 ,mrs4 ,b4 ,let u suppose t ! in/ant aft] y h let a /one fall f a high t[]1 ! =ce ( gravity 7 annihilat$2 ! body w\ld nev]!less cont9ue to move d[nw>ds1 = x w\ld h receiv$ a fir/ impulse f gravity2 & a body once put 9 motion w n /op unless x meets ) "s ob/acle to imp$e its c\rse2 9 ?is case its velocity w\ld be uni=m1 = ?\gh !re w\ld be no ob/acle to ob/ruct its desc5t1 !re w\ld be no =ce to accel]ate x4 ,emily4 ,t is v cle>4 ,mrs4 ,b4 ,!n y h only to add ! p[] ( gravity con/antly act+ on ! /one dur+ its desc5t1 & x w n be difficult to und]/& t its motion w become accel]at$1 s9ce ! gravity :i* acts on ! /one at ! v fir/ in/ant ( its desc5t1 w cont9ue 9 =ce e in/ant1 till x rea*es ! gr\nd4 ,let u suppose t ! impulse giv5 by gravity to ! /one dur+ ! fir/ in/ant ( its desc5t1 be equal to "o2 ! next in/ant we %all f9d t an additional impulse gives ! /one an additional velocity1 equal to "o2 s t ! accumulat$ velocity is n[ equal to two2 ! foll[+ in/ant ano!r impulse increases ! velocity to ?ree1 & s on till ! /one rea*es ! gr\nd4 ,c>ol9e4 ,n[ ,i und]/& x2 ! effects ( prec$+ impulses cont9ue1 :il/ gravity con/antly adds new ones1 & ?us ! velocity is p]petually increas$4 ,mrs4 ,b4 ,yes2 x has be5 asc]ta9$1 bo? by exp]im5t1 & calculations :i* x w\ld be too difficult = u to ent] into1 t heavy bodies ne> ! surface ( ! e>?1 desc5d+ f a height by ! =ce ( gravity1 fall sixte5 feet ! fir/ second ( "t1 ?ree times t di/ance 9 ! next1 five times 9 ! ?ird second1 sev5 times 9 ! f\r?1 & s on1 regul>ly increas+ _! velocities 9 ! proportion ( ! odd numb]s #a1 #c1 #e1 #g1 #i1 c4 accord+ to ! numb] ( seconds dur+ :i* ! body has be5 fall+4 ,emily4 ,if y ?r[ a /one p]p5dicul>ly upw>ds1 is x n ! same l5g? ( "t 9 asc5d+1 t x is 9 desc5d+8 ,mrs4 ,b4 ,exactly2 9 asc5d+1 ! velocity is dim9i%$ by ! =ce ( gravity2 9 desc5d+1 x is accel]at$ by x4 ,c>ol9e4 ,i %\ld !n imag9e t x w\ld fall1 quick] ?an x rose8 ,mrs4 ,b4 ,y mu/ recollect t ! =ce ) :i* x is project$1 mu/ be tak5 into ! acc\nt2 & t ?is =ce is ov]come & de/roy$ by gravity1 be=e ! body beg9s to fall4 ,c>ol9e4 ,b ! =ce ( projection giv5 to a /one 9 ?r[+ x upw>ds1 _c always be equal to ! =ce ( gravity 9 br++ x d[n aga92 = ! =ce ( gravity is always ! same1 :il/ ! degree ( impulse giv5 to ! /one is optional2 ,i may ?r[ x up g5tly1 or ) viol5ce4 ,mrs4 ,b4 ,if y ?r[ x g5tly1 x w n rise high2 p]haps only sixte5 feet1 9 :i* case x w fall 9 "o second ( "t4 ,n[ x is prov$ by exp]im5t1 t an impulse requisite to project a body sixte5 feet upw>ds1 w make x asc5d t height 9 "o second2 "h !n ! times ( ! asc5t & desc5t are equal4 ,b suppos+ x be requir$ to ?r[ a /one twice t height1 ! =ce mu/ be proportionally great]4 ,y see !n1 t ! impulse ( projection 9 ?r[+ a body upw>ds1 is always equal to ! action ( ! =ce ( gravity dur+ its desc5t2 & t :e!r ! body rises to a great] or less di/ance1 ^! two =ces balance ea* o!r4 ,i mu/ n[ expla9 to y :at is meant by ! mom5tum ( bodies4 ,x is ! =ce1 or p[]1 ) :i* a body 9 motion1 /rikes aga9/ ano!r body4 ,! mom5tum ( a body is ! product ( its quantity ( matt]1 multipli$ by its quantity ( motion2 9 o!r words1 its weight multipli$ by its velocity4 ,c>ol9e4 ,! quick] a body moves1 ! great]1 no d\bt1 mu/ be ! =ce :i* x w\ld /rike aga9/ ano!r body4 ,emily4 ,!re=e a light body may h a great] mom5tum ?an a heavi] "o1 provid$ its velocity be suffici5tly increas$2 = in/ance1 ! mom5tum ( an arr[ %ot f a b[1 mu/ be great] ?an t ( a /one ?r[n by ! h&4 ,c>ol9e4 ,we "k also by exp]i5ce1 t ! heavi] a body is1 ! great] is its =ce2 x is n !re=e difficult to und]/&1 t ! :ole p[]1 or mom5tum ( a body1 mu/ be compos$ ( ^! two prop]ties1 its weight & its velocity3 b ,i d n und]/& :y !y %\ld be multipli$1 ! "o by ! o!r2 ,i %\ld h suppos$ t ! quantity ( matt]1 %\ld h be5 add$ to ! quantity ( motion8 ,mrs4 ,b4 ,x is f\nd by exp]im5t1 t if ! weight ( a body is repres5t$ by ! numb] #c1 & its velocity also by #c1 its mom5tum w be repres5t$ by #i1 n by #f1 z w\ld be ! case1 7 ^! figures add$1 in/ead ( be+ multipli$ toge!r4 ,emily4 ,i ?9k t ,i n[ und]/& ! reason ( ?is2 if ! quantity ( matt] is increas$ ?ree-fold1 x mu/ require ?ree times ! =ce to move x ) ! same velocity2 & !n if we wi% to give x ?ree times ! velocity1 x w aga9 require ?ree times ! =ce to produce t effect1 :i* is ?ree times ?ree1 or n9e2 :i* numb] !re=e1 w\ld repres5t ! mom5tum4 ,c>ol9e4 ,i am n q sure t ,i fully compreh5d :at is int5d$1 :5 weight1 & velocity1 are repres5t$ by numb]s alone2 ,i am s us$ to measure space by y>ds & miles1 & weight by p\nds & ounces1 t ,i /ill want to associate !m toge!r 9 my m9d4 ,mrs4 ,b4 ,?is difficulty w be ( v %ort duration3 y h only to be c>eful1 t :5 y repres5t weights & velocities by numb]s1 ! d5om9ations or values ( ! weights & spaces1 mu/ n be *ang$4 ,?us1 if we e/imate ! weight ( "o body 9 ounces1 ! weight ( o!rs ) :i* x is comp>$1 mu/ be e/imat$ 9 ounces1 & n 9 p\nds2 & 9 l mann]1 9 comp>+ velocities1 we mu/ ?r\gh\t1 pres]ve ! same /&>ds bo? ( space & ( "t2 z = in/ance1 ! numb] ( feet 9 "o second1 or ( miles 9 "o h\r4 ,c>ol9e4 ,i n[ und]/& x p]fectly1 & ?9k t ,i %all nev] =get a ?+ :i* y h r5d]$ s cle>4 ,mrs4 ,b4 ,i recomm5d x to y to be v c>eful to rememb] ! def9ition ( ! mom5tum ( bodies1 z x is "o ( ! mo/ important po9ts 9 me*anics3 y w f9d t x is f oppos+ velocity1 to quantity ( matt]1 t ma*9es d]ive _! p[]s4 ,! reaction ( bodies1 is ! next law ( motion :i* ,i mu/ expla9 to y4 ,:5 a body 9 motion /rikes aga9/ ano!r body1 x meets ) resi/ance f x2 ! resi/ance ( ! body at re/ w be equal to ! bl[ /ruck by ! body 9 motion2 or to express myself 9 philosophical language1 action & reaction w be equal1 & 9 opposite directions4 ,c>ol9e4 ,d y mean to say1 t ! action ( ! body :i* /rikes1 is return$ ) equal =ce by ! body :i* receives ! bl[8 ,mrs4 ,b4 ,exactly4 ,c>ol9e4 ,b if a man /rike ano!r on ! face ) 8 fi/1 he surely does n receive z mu* pa9 by ! reaction1 z he inflicts by ! bl[8 ,mrs4 ,b4 ,no2 b ?is is simply ow+ to ! knuckles1 hav+ mu* less feel+ ?an ! face4 ,"h are two ivory balls susp5d$ by ?reads1 7plate #a4 fig4 #c47 draw "o ( !m1 ,a1 a little on "o side1--n[ let x g2--x /rikes1 y see1 aga9/ ! o!r ball ,b1 & drives x (f1 to a di/ance equal to t ?r\gh :i* ! fir/ ball fell2 b ! motion ( ,a is /opp$2 because :5 x /ruck ,b1 x receiv$ 9 return a bl[ equal to t x gave1 & its motion 0 consequ5tly de/roy$4 ,emily4 ,i %\ld h suppos$1 t ! motion ( ! ball ,a 0 de/roy$1 because x _h communicat$ all its motion to ,b4 ,mrs4 ,b4 ,x is p]fectly true1 t :5 "o body /rikes aga9/ ano!r1 ! quantity ( motion communicat$ to ! second body1 is lo/ by ! fir/2 b ?is loss proce$s f ! reaction ( ! body :i* is /ruck4 ,"h are six ivory balls hang+ 9 a r[1 7fig4 #d47 draw ! fir/ out ( ! p]p5dicul>1 & let x fall aga9/ ! second4 ,y see none ( ! balls except ! la/1 appe> to move1 ?is flies (f z f> z ! fir/ ball fell2 c y expla9 ?is8 ,c>ol9e4 ,i believe s4 ,:5 ! fir/ ball /ruck ! second1 x receiv$ a bl[ 9 return1 :i* de/roy$ its motion2 ! second ball1 ?\gh x did n appe> to move1 mu/ h /ruck aga9/ ! ?ird2 ! reaction ( :i* set x at re/2 ! action ( ! ?ird ball mu/ h be5 de/roy$ by ! reaction ( ! f\r?1 & s on till motion 0 communicat$ to ! la/ ball1 :i*1 n be+ react$ ^u1 flies (f4 ,mrs4 ,b4 ,v well expla9$4 ,obs]ve1 t x is only :5 bodies are ela/ic1 z ^! ivory balls are1 & :5 _! masses are equal1 t ! /roke return$ is equal to ! /roke giv51 & t ! /rik+ body loses all its motion4 ,i w %[ y ! diff]5ce ) ^! two balls ( clay1 7fig4 #e47 :i* are n ela/ic2 :5 y raise "o ( ^!1 ,d1 out ( ! p]p5dicul>1 & let x fall aga9/ ! o!r1 ,e1 ! reaction ( ! latt]1 on acc\nt ( its n be+ ela/ic1 is n suffici5t to de/roy ! motion ( ! =m]2 only "p ( ! motion ( ,d w be communicat$ to ,e1 & ! two balls w move on toge!r to d & e1 :i* is n s great a di/ance z t ?r\gh :i* ,d fell4 ,obs]ve h[ useful reaction is 9 nature4 ,birds 9 fly+ /rike ! air ) _! w+s1 & x is ! reaction ( ! air1 :i* enables !m to rise1 or advance =w>ds2 reaction be+ always 9 a contr>y direction to action4 ,c>ol9e4 ,i ?\ght t birds might be light] ?an ! air1 :5 _! w+s 7 exp&$1 & 7 by t means enabl$ to fly4 ,mrs4 ,b4 ,:5 _! w+s are spread1 ?is does n alt] _! weight1 b !y are bett] support$ by ! air1 z !y cov] a great] ext5t ( surface2 yet !y are /ill mu* too heavy to rema9 9 t situation1 )\t cont9ually flapp+ _! w+s1 z y may h notic$ :5 birds hov] ov] _! ne/s3 ! =ce ) :i* _! w+s /rike aga9/ ! air1 mu/ equal ! weight ( _! bodies1 9 ord] t ! reaction ( ! air1 may be able to support t weight2 ! bird w !n rema9 /ation>y4 ,if ! /roke ( ! w+s is great] ?an is requir$ m]ely to support ! bird1 ! reaction ( ! air w make x rise2 if x be less1 x w g5tly desc5d2 & y may h obs]v$ ! l>k1 sometimes rema9+ ) its w+s ext5d$1 b motionless2 9 ?is /ate x drops quietly into its ne/4 ,c>ol9e4 ,?is is inde$ a beautiful effect ( ! law ( reaction6 ,b if fly+ is m]ely a me*anical op]ation1 ,mrs4 ,b41 :y %\ld we n con/ruct w+s1 adapt$ to ! size ( our bodies1 fa/5 !m to our %\ld]s1 move !m ) our arms1 & so> into ! air8 ,mrs4 ,b4 ,su* an exp]im5t has be5 repeat$ly attempt$1 b nev] ) success2 & x is n[ consid]$ z totally impracticable4 ,! muscul> p[] ( birds1 is incomp>ably great] 9 proportion to _! weight1 ?an t ( man2 7 we !re=e furni%$ ) w+s suffici5tly l>ge to enable u to fly1 we %\ld n h /r5g? to put !m 9 motion4 ,9 swimm+1 a simil> action is produc$ on ! wat]1 to t on ! air1 9 fly+2 9 r[+1 also1 y /rike ! wat] ) ! o>s1 9 a direction opposite to t 9 :i* ! boat is requir$ to move1 & x is ! reaction ( ! wat] on ! o>s :i* drives ! boat along4 ,emily4 ,y said1 t x 0 9 ela/ic bodies only1 t ! :ole motion ( "o body1 w\ld be communicat$ to ano!r2 pray :at bodies are ela/ic1 besides ! air8 ,mrs4 ,b4 ,9 speak+ ( ! air1 ,i ?9k we def9$ ela/icity to be a prop]ty1 by means ( :i* bodies t are compress$1 return to _! =m] /ate4 ,if ,i b5d ?is cane1 z soon z ,i leave x at lib]ty1 x recov]s its =m] position2 if ,i press my f+] ^u y\r arm1 z soon z ,i remove x1 ! fle%1 by virtue ( its ela/icity1 rises & de/roys ! impression ,i made4 ,( all bodies1 ! air is ! mo/ em95t = ?is prop]ty1 & x has !nce obta9$ ! "n ( an ela/ic fluid4 ,h>d bodies are 9 ! next degree ela/ic2 if two ivory1 or h>d5$ /eel balls are /ruck toge!r1 ! p>ts at :i* !y t\*1 w be flatt5$2 b _! ela/icity w make !m in/antane\sly resume _! =m] %ape4 ,c>ol9e4 ,b :5 two ivory balls /rike aga9/ ea* o!r1 z !y con/antly d on a billi>d table1 no m>k or impression is made by ! /roke4 ,mrs4 ,b4 ,i beg y\r p>don2 y _c1 x is true1 p]ceive any m>k1 because _! ela/icity in/antly de/roys all trace ( x4 ,s(t bodies1 :i* easily reta9 impressions1 su* z clay1 wax1 tall[1 butt]1 c4 h v little ela/icity2 b ( all descriptions ( bodies1 liquids are ! lea/ ela/ic4 ,emily4 ,if seal+-wax 7 ela/ic1 in/ead ( reta9+ ! impression ( a seal1 x w\ld resume a smoo? surface1 z soon z ! weight ( ! seal 0 remov$4 ,b pray :at is x t produces ! ela/icity ( bodies8 ,mrs4 ,b4 ,!re is great div]sity ( op9ion ^u t po9t1 & ,i _c pret5d to decide :i* approa*es ne>e/ to ! tru?4 ,ela/icity implies susceptibility ( compression1 & ! susceptibility ( compression dep5ds ^u ! porosity ( bodies2 = 7 !re no pores or spaces betwe5 ! p>ticles ( matt] ( :i* a body is compos$1 x c\ld n be compress$4 ,c>ol9e4 ,t is to say1 t if ! p>ticles ( bodies 7 z close toge!r z possible1 !y c\ld n be squeez$ clos]4 ,emily4 ,bodies !n1 ^: p>ticles are mo/ di/ant f ea* o!r1 mu/ be mo/ susceptible ( compression1 & consequ5tly mo/ ela/ic2 & ?is y say is ! case ) air1 :i* is p]haps ! lea/ d5se ( all bodies8 ,mrs4 ,b4 ,y w n 9 g5]al f9d ?is rule hold good2 = liquids h sc>cely any ela/icity1 :il/ h>d bodies are em95t = ?is prop]ty1 ?\gh ! latt] are c]ta9ly ( mu* great] d5sity ?an ! =m]2 ela/icity implies1 !re=e1 n only a susceptibility ( compression1 b dep5ds ^u ! p[] possess$ by ! body1 ( resum+ its =m] /ate aft] compression1 9 consequ5ce ( ! peculi> arrangem5t ( its p>ticles4 ,c>ol9e4 ,b surely !re c be no pores 9 ivory & metals1 ,mrs4 ,b42 h[ !n c !y be susceptible ( compression8 ,mrs4 ,b4 ,! pores ( su* bodies are invisible to ! nak$ eye1 b y mu/ n !nce conclude t !y h none2 x is1 on ! contr>y1 well asc]ta9$ t gold1 "o ( ! mo/ d5se ( all bodies1 is extremely por\s2 & t ^! pores are suffici5tly l>ge to admit wat] :5 /rongly compress$1 to pass ?r\gh !m4 ,?is 0 %[n by a celebrat$ exp]im5t made _m ye>s ago at ,flor5ce4 ,emily4 ,if wat] c pass ?r\gh gold1 !re mu/ c]ta9ly be pores or int]/ices :i* af=d x a passage2 & if gold is s por\s1 :at mu/ o!r bodies be1 :i* are s mu* less d5se ?an gold6 ,mrs4 ,b4 ,! *ief diff]5ce 9 ?is respect1 is ,i believe1 t ! pores 9 "s bodies are l>g] ?an 9 o!rs2 9 cork1 sponge & bread1 !y =m consid]able cavities2 9 wood & /one1 :5 n poli%$1 !y are g5]ally p]ceptible to ! nak$ eye2 :il/ 9 ivory1 metals1 & all v>ni%$ & poli%$ bodies1 !y _c be disc]n$4 ,to give y an idea ( ! extreme porosity ( bodies1 sir ,isaac ,newton conjectur$ t if ! e>? 7 s compress$ z to be absolutely )\t pores1 its dim5sions might possibly n be m ?an a cubic in*4 ,c>ol9e4 ,:at an idea6 ,7 we n indebt$ to sir ,isaac ,newton = ! !ory ( attraction1 ,i %\ld be tempt$ to laugh at him = su* a supposition4 ,:at insignificant little creatures we %\ld be6 ,mrs4 ,b4 ,if our consequ5ce arose f ! size ( our bodies1 we %\ld inde$ be b pigmies1 b rememb] t ! m9d ( ,newton 0 n circumscrib$ by ! dim5sions ( its envelope4 ,emily4 ,x is1 h[ev]1 =tunate t heat keeps ! pores ( matt] op5 & di/5d$1 & prev5ts ! attraction ( cohesion f squeez+ u into a nut-%ell4 ,mrs4 ,b4 ,let u n[ return to ! subject ( reaction1 on :i* we h "s fur!r obs]vations to make4 ,x is because reaction is 9 its direction opposite to action1 t reflect$ motion is produc$4 ,if y ?r[ a ball aga9/ ! wall1 x reb\nds2 ?is return ( ! ball is ow+ to ! reaction ( ! wall aga9/ :i* x /ruck1 & is call$ reflect$ motion4 ,emily4 ,& ,i n[ und]/& :y balls fill$ ) air reb\nd bett] ?an ^? /uff$ ) bran or wool2 air be+ mo/ susceptible ( compression & mo/ ela/ic1 ! reaction is m complete4 ,c>ol9e4 ,i h obs]v$ t :5 ,i ?r[ a ball /raight aga9/ ! wall1 x returns /raight to my h&2 b if ,i ?r[ x obliquely upw>ds1 x reb\nds /ill high]1 & ,i cat* x :5 x falls4 ,mrs4 ,b4 ,y %\ld n say /raight1 b p]p5dicul>ly aga9/ ! wall2 = /raight is a g5]al t]m = l9es 9 all directions :i* are nei!r curv$ nor b5t1 & is !re=e equally applicable to oblique or p]p5dicul> l9es4 ,c>ol9e4 ,i ?\ght t p]p5dicul>ly meant ei!r directly upw>ds or d[nw>ds8 ,mrs4 ,b4 ,9 ^? directions l9es are p]p5dicul> to ! e>?4 ,a p]p5dicul> l9e has always a ref]5ce to some?+ t[>ds :i* x is p]p5dicul>2 t is to say1 t x incl9es nei!r to ! "o side or ! o!r1 b makes an equal angle on e side4 ,d y und]/& :at an angle is8 ,c>ol9e4 ,yes1 ,i believe s3 x is ! space conta9$ betwe5 two l9es meet+ 9 a po9t4 ,mrs4 ,b4 ,well !n1 let ! l9e ,a ,b 7plate #b4 fig4 #a47 repres5t ! floor ( ! room1 & ! l9e ,c ,d t 9 :i* y ?r[ a ball aga9/ x2 ! l9e ,c ,d1 y w obs]ve1 =ms two angles ) ! l9e ,a ,b1 & ^? two angles are equal4 ,emily4 ,h[ c ! angles be equal1 :ile ! l9es :i* compose !m are ( unequal l5g?8 ,mrs4 ,b4 ,an angle is n measur$ by ! l5g? ( ! l9es1 b by _! op5+1 or ! space betwe5 !m4 ,emily4 ,yet ! long] ! l9es are1 ! great] is ! op5+ betwe5 !m4 ,mrs4 ,b4 ,take a pair ( compasses & draw a circle ov] ^! spaces1 mak+ ! angul> po9t ! c5tre4 ,emily4 ,to :at ext5t mu/ ,i op5 ! compasses8 ,mrs4 ,b4 ,y may draw ! circle :at size y please1 provid$ t x cuts ! l9es ( ! angles we are to measure4 ,all circles1 ( :atev] dim5sions1 are suppos$ to be divid$ into #cfj equal p>ts1 call$ degrees2 ! op5+ ( an angle1 be+ !re=e a portion ( a circle1 mu/ conta9 a c]ta9 numb] ( degrees3 ! l>g] ! angle ! great] is ! numb] ( degrees1 & two angles are said to be equal1 :5 !y conta9 an equal numb] ( degrees4 ,emily4 ,n[ ,i und]/& x4 ,z ! dim5sion ( an angle dep5ds ^u ! numb] ( degrees conta9$ betwe5 its l9es1 x is ! op5+1 & n ! l5g? ( its l9es1 :i* det]m9es ! size ( ! angle4 ,mrs4 ,b4 ,v well3 n[ t y h a cle> idea ( ! dim5sions ( angles1 c y tell me h[ _m degrees are conta9$ 9 ! two angles =m$ by "o l9e fall+ p]p5dicul>ly on ano!r1 z 9 ! figure ,i h j drawn8 ,emily4 ,y mu/ all[ me to put "o foot ( ! compasses at ! po9t ( ! angles1 & draw a circle r\nd !m1 & !n ,i ?9k ,i %all be able to answ] y\r "q3 ! two angles are toge!r j equal to half a circle1 !y conta9 !re=e #ij degrees ea*2 #ij degrees be+ a qu>t] ( #cfj4 ,mrs4 ,b4 ,an angle ( #ij degrees or "o-f\r? ( a circle is call$ a "r angle1 & :5 "o l9e is p]p5dicul> to ano!r1 & di/ant f its ends1 x =ms1 y see1 7fig4 #a47 a "r angle on ei!r side4 ,angles conta9+ m ?an #ij degrees are call$ obtuse angles1 7fig4 #b47 & ^? conta9+ less ?an #ij degrees are call$ acute angles1 7fig4 #c47 ,c>ol9e4 ,! angles ( ?is squ>e table are "r angles1 b ^? ( ! octagon table are obtuse angles2 & ! angles ( %>p po9t$ in/rum5ts are acute angles4 ,illu/ration3 ,,plate ,,ii4 ,mrs4 ,b4 ,v well4 ,to return n[ to y\r obs]vation1 t if a ball is ?r[n obliquely aga9/ ! wall1 x w n reb\nd 9 ! same direction2 tell me1 h y ev] play$ at billi>ds8 ,c>ol9e4 ,yes1 frequ5tly2 & ,i h obs]v$ t :5 ,i pu% ! ball p]p5dicul>ly aga9/ ! cu%ion1 x returns 9 ! same direction2 b :5 ,i s5d x obliquely to ! cu%ion1 x reb\nds obliquely1 b on an opposite side2 ! ball 9 ?is latt] case describes an angle1 ! po9t ( :i* is at ! cu%ion4 ,i h obs]v$ too1 t ! m obliquely ! ball is /ruck aga9/ ! cu%ion1 ! m obliquely x reb\nds on ! opposite side1 s t a billi>d play] c calculate ) great accuracy 9 :at direction x w return4 ,mrs4 ,b4 ,v well4 ,?is figure 7fig4 #d4 plate #b47 repres5ts a billi>d table2 n[ if y draw a l9e ,a ,b f ! po9t :]e ! ball ,a /rikes p]p5dicul> to ! cu%ion1 y w f9d t x w divide ! angle :i* ! ball describes into two p>ts1 or two angles2 ! "o w %[ ! obliquity ( ! direction ( ! ball 9 its passage t[>ds ! cu%ion1 ! o!r its obliquity 9 its passage back f ! cu%ion4 ,! fir/ is call$ ! angle ( incid5ce1 ! o!r ! angle ( reflection2 & ^! angles are always equal1 if ! bodies are p]fectly ela/ic4 ,c>ol9e4 ,?is !n is ! reason :y1 :5 ,i ?r[ a ball obliquely aga9/ ! wall1 x reb\nds 9 an opposite oblique direction1 =m+ equal angles ( incid5ce & ( reflection4 ,mrs4 ,b4 ,c]ta9ly2 & y w f9d t ! m obliquely y ?r[ ! ball1 ! m obliquely x w reb\nd4 ,we mu/ n[ conclude2 b ,i %all h "s fur!r obs]vations to make ^u ! laws ( motion1 at our next meet+4 ,que/ions #a4 7,pg4 #cb7 ,on :at is ! sci5ce ( me*anics f\nd$8 #b4 7,pg4 #cb7 ,9 :at does motion consi/8 #c4 7,pg4 #cc7 ,:at is ! consequ5ce ( in]tia1 on a body at re/8 #d4 7,pg4 #cc7 ,:at d we call t :i* produces motion8 #e4 7,pg4 #cc7 ,give "s examples4 #f4 7,pg4 #cc7 ,:at may we say ( gravity1 ( cohesion1 & ( heat1 z =ces8 #g4 7,pg4 #cc7 ,h[ w a body move1 if act$ on by a s+le =ce8 #h4 7,pg4 #cc7 ,:at is ! reason ( ?is8 #i4 7,pg4 #cc7 ,:at d we int5d by ! t]m velocity1 & to :at is x proportional8 #aj4 7,pg4 #cc7 ,velocity is divid$ into absolute & relative2 :at is meant by absolute velocity8 #aa4 7,pg4 #cc7 ,h[ is relative velocity di/+ui%$8 #ab4 7,pg4 #cd7 ,h[ d we measure ! velocity ( a body8 #ac4 7,pg4 #cd7 ,! "t8 #ad4 7,pg4 #cd7 ,! space8 #ae4 7,pg4 #cd7 ,:at is uni=m motion8 & give an example4 #af4 7,pg4 #cd7 ,h[ is uni=m motion produc$8 #ag4 7,pg4 #cd7 ,a ball /ruck by a bat gradually loses its motion2 :at causes produce ?is effect8 #ah4 7,pg4 #ce7 ,if gravity did n draw a project$ body t[>ds ! e>?1 & ! resi/ance ( ! air 7 remov$1 :at w\ld be ! consequ5ce8 #ai4 7,pg4 #ce7 ,9 ?is case w\ld n a great degree ( =ce be requir$ to produce a cont9u$ motion8 #bj4 7,pg4 #ce7 ,:at is ret>d$ motion8 #ba4 7,pg4 #ce7 ,give "s examples4 #bb4 7,pg4 #cf7 ,:at is accel]at$ motion8 #bc4 7,pg4 #cf7 ,give an example4 #bd4 7,pg4 #cf7 ,expla9 ! mode 9 :i* gravity op]ates 9 produc+ ?is effect4 #be4 7,pg4 #cg7 ,:at numb] ( feet w a heavy body desc5d 9 ! fir/ second ( its fall1 & at :at rate w its velocity increase8 #bf4 7,pg4 #cg7 ,:at is ! diff]5ce 9 ! "t ( ! asc5t & desc5t1 ( a /one1 or o!r body ?r[n upw>ds8 #bg4 7,pg4 #cg7 ,by :at reason+ is x prov$ t !re is no diff]5ce8 #bh4 7,pg4 #ch7 ,:at is meant by ! mom5tum ( a body8 #bi4 7,pg4 #ch7 ,h[ d we asc]ta9 ! mom5tum8 #cj4 7,pg4 #ch7 ,h[ may a light body h a great] mom5tum ?an "o :i* is heavi]8 #ca4 7,pg4 #ch7 ,:y mu/ we multiply ! weight & velocity toge!r 9 ord] to f9d ! mom5tum8 #cb4 7,pg4 #ci7 ,:5 we repres5t weight & velocity by numb]s1 :at mu/ we c>efully obs]ve8 #cc4 7,pg4 #ci7 ,:y is x p>ticul>ly important1 to und]/& ! nature ( mom5tum8 #cd4 7,pg4 #ci7 ,:at is meant by reaction1 & :at is ! rule respect+ x8 #ce4 7,pg4 #ci7 ,h[ is ?is exemplifi$ by ! ivory balls repres5t$ 9 plate #a4 fig4 #c8 #cf4 7,pg4 #dj7 ,expla9 ! mann] 9 :i* ! six balls repres5t$ 9 fig4 #d1 illu/rate ?is fact4 #cg4 7,pg4 #dj7 ,:at mu/ be ! nature ( bodies1 9 :i* ! :ole motion is communicat$ f "o to ! o!r8 #ch4 7,pg4 #dj7 ,:at is ! result if ! balls are n ela/ic1 & h[ is ?is expla9$ by fig4 #e8 #ci4 7,pg4 #dj7 ,h[ w reaction assi/ u 9 expla9+ ! flight ( a bird8 #dj4 7,pg4 #dj7 ,h[ mu/ _! w+s op]ate 9 enabl+ !m to rema9 /ation>y1 to rise1 & to desc5d8 #da4 7,pg4 #da7 ,:y _c a man fly by ! aid ( w+s8 #db4 7,pg4 #da7 ,h[ does reaction op]ate 9 enabl+ u to swim1 or to r[ a boat8 #dc4 7,pg4 #da7 ,:at con/itutes ela/icity8 #dd4 7,pg4 #da7 ,give "s examples4 #de4 7,pg4 #da7 ,:at "n is giv5 to air1 & = :at reason8 #df4 7,pg4 #da7 ,:at h>d bodies are m5tion$ z ela/ic8 #dg4 7,pg4 #da7 ,d ela/ic bodies exhibit any ind5tation aft] a bl[8 & :y n8 #dh4 7,pg4 #db7 ,:at d we conclude f ela/icity respect+ ! contact ( ! p>ticles ( a body8 #di4 7,pg4 #db7 ,are ^? bodies always ! mo/ ela/ic1 :i* are ! lea/ d5se8 #ej4 7,pg4 #db7 ,give examples to prove t ?is is n ! case4 #ea4 7,pg4 #db7 ,all bodies are believ$ to be por\s1 :at is said on ?is subject respect+ gold8 #eb4 7,pg4 #dc7 ,:at conjecture 0 made by sir ,isaac ,newton1 respect+ ! porosity ( bodies 9 g5]al8 #ec4 7,pg4 #dc7 ,if y ?r[ an ela/ic body aga9/ a wall1 x w reb\nd2 :at is ?is occasion$ by1 & :at is ?is return motion call$8 #ed4 7,pg4 #dc7 ,:at d we mean by a p]p5dicul> l9e8 #ee4 7,pg4 #dc7 ,:at is an angle8 #ef4 7,pg4 #dc7 ,:at is repres5t$ by fig4 #a4 plate #b8 #eg4 7,pg4 #dd7 ,h ! l5g? ( ! l9es :i* meet 9 a po9t1 any ?+ to d ) ! measurem5t ( an angle8 #eh4 7,pg4 #dd7 ,:at use c we make ( compasses 9 measur+ an angle8 #ei4 7,pg4 #dd7 ,into :at numb] ( p>ts d we suppose a :ole circle divid$1 & :at are ^! p>ts call$8 #fj4 7,pg4 #dd7 ,:5 are two angles said to be equal8 #fa4 7,pg4 #dd7 ,^u :at does ! dim5sion ( an angle dep5d8 #fb4 7,pg4 #dd7 ,:at numb] ( degrees1 & :at portion ( a circle is !re 9 a "r angle8 #fc4 7,pg4 #dd7 ,h[ mu/ "o l9e be situat$ on ano!r to =m two "r angles8 7fig4 #a47 #fd4 7,pg4 #dd7 ,figure #b repres5ts an angle ( m ?an #ij degrees1 :at is t call$8 #fe4 7,pg4 #dd7 ,:at are ^? ( less ?an #ij degrees call$ z 9 fig4 #c8 #ff4 7,pg4 #de7 ,if y make an ela/ic ball /rike a body at "r angles1 h[ w x return8 #fg4 7,pg4 #de7 ,h[ if x /rikes obliquely8 #fh4 7,pg4 #de7 ,expla9 by fig4 #d :at is meant by ! angles ( incid5ce & ( reflection4 ,,conv]sation ,,iv4 ,,on ,,comp\nd ,,motion4 ,,comp\nd ,,motion1 ,,! ,,result ,,( ,,two ,,opposite ,,=ces4 ,,( ,,curvil9e> ,,motion1 ,,! ,,result ,,( ,,two ,,=ces4 ,,c5tre ,,( ,,motion1 ,,! ,,po9t ,,at ,,re/ ,,:ile ,,! ,,o!r ,,p>ts ,,( ,,! ,,body ,,move ,,r\nd ,,x4 ,,c5tre ,,( ,,magnitude1 ,,! ,,middle ,,( ,a ,,body4 ,,c5tripetal ,,=ce1 ,,t ,,:i* ,,impels ,a ,,body ,,t[>ds ,a ,,fix$ ,,c5tral ,,po9t4 ,,c5trifugal ,,=ce1 ,,t ,,:i* ,,impels ,a ,,body ,,to ,,fly ,,f ,,! ,,c5tre4 ,,fall ,,( ,,bodies ,,9 ,a ,,p>abola4 ,,c5tre ,,( ,,gravity1 ,,! ,,po9t ,,ab\t ,,:i* ,,! ,,p>ts ,,balance ,,ea* ,,o!r4 ,,mrs4 ,b4 ,i mu/ n[ expla9 to y ! nature ( comp\nd motion4 ,let u suppose a body to be /ruck by two equal =ces 9 opposite directions1 h[ w x move8 ,emily4 ,if ! =ces are equal1 & _! directions are 9 exact opposition to ea* o!r1 ,i suppose ! body w\ld n move at all4 ,mrs4 ,b4 ,y are p]fectly "r2 b suppose ! =ces in/ead ( act+ ^u ! body 9 direct opposition to ea* o!r1 7 to move 9 l9es =m+ an angle ( n9ety degrees1 z ! l9es ,y ,a1 ,x ,a1 7fig4 #e4 plate #b47 & 7 to /rike ! ball ,a1 at ! same in/ant2 w\ld x n move8 ,emily4 ,! =ce ,x alone1 w\ld s5d x t[>ds ,b1 & ! =ce ,y t[>ds ,c2 & s9ce ^! =ces are equal1 ,i d n "k h[ ! body c obey "o impulse r ?an ! o!r2 & yet ,i ?9k ! ball w\ld move1 because z ! two =ces d n act 9 direct opposition1 !y _c entirely de/roy ! effect ( ea* o!r4 ,mrs4 ,b4 ,v true2 ! ball !re=e w n foll[ ! direction ( ei!r ( ! =ces1 b w move 9 a l9e betwe5 !m1 & w rea* ,d 9 ! same space ( "t1 t ! =ce ,x w\ld h s5t x to ,b1 & ! =ce ,y w\ld h s5t x to ,c4 ,n[ if y draw two l9es1 "o f ,b1 p>allel to ,a ,c1 & ! o!r f ,c1 p>allel to ,a ,b1 !y w meet 9 ,d1 & y w =m a squ>e2 ! oblique l9e :i* ! body describes1 is call$ ! diagonal ( ! squ>e4 ,c>ol9e4 ,t is v cle>1 b suppos+ ! two =ces to be unequal1 t ! =ce ,x1 = in/ance1 be twice z great z ! =ce ,y8 ,mrs4 ,b4 ,!n ! =ce ,x1 w\ld drive ! ball twice z f> z ! =ce ,y1 consequ5tly y mu/ draw ! l9e ,a ,b 7fig4 #f47 twice z long z ! l9e ,a ,c1 ! body w 9 ?is case move to ,d2 & if y draw l9es f ! po9ts ,b & ,c1 exactly z direct$ 9 ! la/ example1 !y w meet 9 ,d1 & y w f9d t ! ball has mov$ 9 ! diagonal ( a rectangle4 ,emily4 ,all[ me to put ano!r case4 ,suppose ! two =ces are unequal1 b d n act on ! ball 9 ! direction ( a "r angle1 b 9 t ( an acute angle1 :at w result8 ,mrs4 ,b4 ,prolong ! l9es 9 ! directions ( ! two =ces1 & y w soon discov] :i* way ! ball w be impell$2 x w move f ,a to ,d1 9 ! diagonal ( a p>allelogram1 7fig4 #g47 ,=ces act+ 9 ! direction ( l9es =m+ an obtuse angle1 w also produce motion 9 ! diagonal ( a p>allelogram4 ,= in/ance1 if ! body set out f ,b1 in/ead ( ,a1 & 0 impell$ by ! =ces ,x & ,y1 x w\ld move 9 ! dott$ diagonal ,b ,c4 ,we may n[ proce$ to curvil9e> motion3 ?is is ! result ( two =ces act+ on a body2 by "o ( :i*1 x is project$ =w>d 9 a "r l9e2 :il/ by ! o!r1 x is drawn or impell$ t[>ds a fix$ po9t4 ,= in/ance1 :5 ,i :irl ?is ball1 :i* is fa/5$ to my h& ) a /r+1 ! ball moves 9 a circul> direction1 because x is act$ on by two =ces2 t :i* ,i give x1 :i* repres5ts ! =ce ( projection1 & t ( ! /r+ :i* conf9es x to my h&4 ,if1 dur+ its motion y 7 sudd5ly to cut ! /r+1 ! ball w\ld fly (f 9 a /raight l9e2 be+ releas$ f t conf9em5t :i* caus$ x to move r\nd a fix$ po9t1 x w\ld be act$ on by "o =ce only2 & motion produc$ by "o =ce1 y "k1 is always 9 a "r l9e4 ,c>ol9e4 ,?is circul> motion1 is a little m difficult to compreh5d ?an comp\nd motion 9 /raight l9es4 ,mrs4 ,b4 ,y h se5 h[ ! wat] is ?r[n (f f a gr9d/one1 :5 turn$ rapidly r\nd2 ! p>ticles ( ! /one itself h ! same t5d5cy1 & w\ld also fly (f1 0 n _! attraction ( cohesion1 great] ?an t ( wat]4 ,& inde$ x sometimes happ5s1 t l>ge gr9d/ones fly to pieces f ! rapidity ( _! motion4 ,emily4 ,9 ! same way1 ! rim & spokes ( a :eel1 :5 9 rapid motion1 w\ld be driv5 /raight =w>ds 9 a "r l9e1 7 !y n conf9$ to a fix$ po9t1 r\nd :i* !y are compell$ to move4 ,mrs4 ,b4 ,v well4 ,y mu/ n[ le>n to di/+ui% betwe5 :at is call$ ! c5tre ( motion1 & ! axis ( motion2 ! =m] be+ consid]$ z a po9t1 ! latt] z a l9e4 ,:5 a body1 l ! ball at ! end ( ! /r+1 revolves 9 a circle1 ! c5tre ( ! circle is call$ ! c5tre ( its motion1 & ! body is said to revolve 9 a plane2 because a l9e ext5d$ f ! revolv+ body1 to ! c5tre ( motion1 w\ld describe a plane1 or flat surface4 ,:5 a body revolves r\nd itself1 z a ball susp5d$ by a /r+1 & made to sp9 r\nd1 or a top sp9n+ on ! floor1 :il/ x rema9s on ! same spot2 ?is revolution is r\nd an imag9>y l9e pass+ ?r\gh ! body1 & ?is l9e is call$ its axis ( motion4 ,c>ol9e4 ,! axle ( a gr9d/one1 is !n ! axis ( its motion2 b is ! c5tre ( motion always 9 ! middle ( a body8 ,mrs4 ,b4 ,no1 n always4 ,! middle po9t ( a body1 is call$ its c5tre ( magnitude1 or position1 t is1 ! c5tre ( its mass or bulk4 ,bodies h also ano!r c5tre1 call$ ! c5tre ( gravity1 :i* ,i %all expla9 to y2 b at pres5t we mu/ conf9e ourselves to ! axis ( motion4 ,?is l9e y mu/ obs]ve rema9s at re/1 :il/ all ! o!r p>ts ( ! body move ar\nd x2 :5 y sp9 a top1 ! axis is /ation>y1 :il/ e o!r "p is 9 motion r\nd x4 ,c>ol9e4 ,b a top g5]ally has a motion =w>ds besides its sp9n+ motion2 & !n no po9t )9 x c be at re/8 ,mrs4 ,b4 ,:at ,i say ( ! axis ( motion1 relates only to circul> motion2 t is to say1 motion r\nd a l9e1 & n to t :i* a body may h at ! same "t 9 any o!r direction4 ,!re is "o circum/ance to :i* y mu/ c>efully att5d2 namely1 t ! fur!r any "p ( a body is f ! axis ( motion1 ! great] is its velocity3 z y approa* t l9e1 ! velocity ( ! p>ts gradually dim9i% till y rea* ! axis ( motion1 :i* is p]fectly at re/4 ,c>ol9e4 ,b1 if e "p ( ! same body did n move ) ! same velocity1 t "p :i* mov$ quicke/1 mu/ be sep>at$ f ! re/ ( ! body1 & leave x beh9d8 ,mrs4 ,b4 ,y p]plex y\rself by conf\nd+ ! idea ( circul> motion1 ) t ( motion 9 a "r l9e2 y mu/ ?9k only ( ! motion ( a body r\nd a fix$ l9e1 & y w f9d1 t if ! p>ts f>!/ f ! c5tre _h n ! greate/ velocity1 ^? p>ts w\ld n be able to keep up ) ! re/ ( ! body1 & w\ld be left beh9d4 ,d n ! extremities ( ! vanes ( a w9dmill move ov] a mu* great] space1 ?an ! p>ts ne>e/ ! axis ( motion8 7plate #c4 fig4 #a47 ,! ?ree dott$ circles repres5t ! pa?s 9 :i* ?ree diff]5t p>ts ( ! vanes move1 & ?\gh ! circles are ( diff]5t dim5sions1 ea* ( !m is describ$ 9 ! same space ( "t4 ,c>ol9e4 ,c]ta9ly !y are2 & ,i n[ only wond]1 t we nei!r ( u ev] made ! obs]vation be=e3 & ! same effect mu/ take place 9 a solid body1 l ! top 9 sp9n+2 ! mo/ bulg+ "p ( ! surface mu/ move ) ! greate/ rapidity4 ,mrs4 ,b4 ,! =ce :i* draws a body t[>ds a c5tre1 r\nd :i* x moves1 is call$ ! c5tripetal =ce2 & t =ce1 :i* impels a body to fly f ! c5tre1 is call$ ! c5trifugal =ce2 :5 a body revolves r\nd a c5tre1 ^! two =ces con/antly balance ea* o!r2 o!rwise ! revolv+ body w\ld ei!r approa* ! c5tre or rec$e f x1 accord+ z ! "o or ! o!r prevail$4 ,c>ol9e4 ,:5 ,i see any body mov+ 9 a circle1 ,i %all rememb]1 t x is act$ on by two =ces4 ,mrs4 ,b4 ,motion1 ei!r 9 a circle1 an ellipsis1 or any o!r curve-l9e1 mu/ be ! result ( ! action ( two =ces2 = y "k1 t ! impulse ( "o s+le =ce1 always produces motion 9 a "r l9e4 ,emily4 ,& if any cause %\ld de/roy ! c5tripetal =ce1 ! c5trifugal =ce w\ld alone impel ! body1 & x w\ld1 ,i suppose1 fly (f 9 a /raight l9e f ! c5tre to :i* x _h be5 conf9$4 ,mrs4 ,b4 ,x w\ld n fly (f 9 a "r l9e f ! c5tre2 b 9 a "r l9e 9 ! direction 9 :i* x 0 mov+1 at ! in/ant ( its release2 if a /one1 :irl$ r\nd 9 a sl+1 gets loose at ! po9t ,a1 7plate #c4 fig4 #b47 x flies (f 9 ! direction ,a ,b2 ?is l9e is call$ a tang5t1 x t\*es ! circumf]5ce ( ! circle1 & =ms a "r angle ) a l9e drawn f t po9t ( ! circumf]5ce to ! c5tre ( ! circle ,c4 ,emily4 ,y say1 t motion 9 a curve-l9e1 is ow+ to two =ces act+ ^u a body2 b :5 ,i ?r[ ?is ball 9 a horizontal direction1 x describes a curve-l9e 9 fall+2 & yet x is only act$ ^u by ! =ce ( projection2 !re is no c5tripetal =ce to conf9e x1 or produce comp\nd motion4 ,mrs4 ,b4 ,a ball ?us ?r[n1 is act$ ^u by no less ?an ?ree =ces2 ! =ce ( projection1 :i* y communicate to x2 ! resi/ance ( ! air ?r\gh :i* x passes1 :i* dim9i%es its velocity1 )\t *ang+ its direction2 & ! =ce ( gravity1 :i* f9ally br+s x to ! gr\nd4 ,! p[] ( gravity1 & ! resi/ance ( ! air1 be+ always great] ?an any =ce ( projection we c give a body1 ! latt] is gradually ov]come1 & ! body br\ght to ! gr\nd2 b ! /rong] ! projectile =ce1 ! long] w ^! p[]s be 9 subdu+ x1 & ! fur!r ! body w g be=e x falls4 ,c>ol9e4 ,a %ot fir$ f a cannon1 = in/ance1 w g mu* fur!r1 ?an a /one project$ by ! h&4 ,mrs4 ,b4 ,bodies ?us project$1 y obs]ve1 describe a curve-l9e 9 _! desc5t2 c y acc\nt = t8 ,c>ol9e4 ,no2 ,i d n und]/& :y x %\ld n fall 9 ! diagonal ( a squ>e4 ,mrs4 ,b4 ,y mu/ consid] t ! =ce ( projection is /ronge/ :5 ! ball is fir/ ?r[n2 ?is =ce1 z x proce$s1 be+ weak5$ by ! cont9u$ resi/ance ( ! air1 ! /one1 !re=e1 beg9s by mov+ 9 a horizontal direction2 b z ! /rong] p[]s prevail1 ! direction ( ! ball w gradually *ange f a horizontal1 to a p]p5dicul> l9e4 ,projection alone1 w\ld drive ! ball ,a1 to ,b1 7fig4 #c47 gravity w\ld br+ x to ,c2 !re=e1 :5 act$ on 9 diff]5t directions1 by ^! two =ces1 x moves betwe51 gradually incl9+ m & m to ! =ce ( gravity1 9 proportion z ?is accumulates2 in/ead !re=e ( rea*+ ! gr\nd at ,d1 z y suppose x w\ld1 x falls some:]e ab\t ,e4 ,c>ol9e4 ,x is precisely s2 look ,emily1 z ,i ?r[ ?is ball directly upw>ds1 h[ gravity & ! resi/ance ( ! air conqu] projection4 ,n[ ,i w ?r[ x upw>ds obliquely3 see1 ! =ce ( projection enables x1 = an in/ant1 to act 9 opposition to t ( gravity2 b x is soon br\ght d[n aga94 ,mrs4 ,b4 ,! curve-l9e :i* ! ball has describ$1 is call$ 9 geometry a p>abola2 b :5 ! ball is ?r[n p]p5dicul>ly upw>ds1 x w desc5d p]p5dicul>ly2 because ! =ce ( projection1 & t ( gravity1 are 9 ! same l9e ( direction4 ,illu/ration3 ,,plate ,,iii4 ,we h notic$ ! c5tres ( magnitude1 & ( motion2 b ,i h n yet expla9$ to y1 :at is meant by ! c5tre ( gravity2 x is t po9t 9 a body1 ab\t :i* all ! p>ts exactly balance ea* o!r2 if !re=e t po9t be support$1 ! body w n fall4 ,d y und]/& ?is8 ,emily4 ,i ?9k s2 if ! p>ts r\nd ab\t ?is po9t h an equal t5d5cy to fall1 !y w be 9 equilibrium1 & z long z ?is po9t is support$1 ! body _c fall4 ,mrs4 ,b4 ,c>ol9e1 :at w\ld be ! effect1 7 ! body support$ 9 any o!r s+le po9t8 ,c>ol9e4 ,! surr\nd+ p>ts no long] balanc+ ea* o!r1 ! body1 ,i suppose1 w\ld fall on ! side at :i* ! p>ts are heavie/4 ,mrs4 ,b4 ,infallibly2 :5ev] ! c5tre ( gravity is unsupport$1 ! body mu/ fall4 ,?is sometimes happ5s ) an ov]load$ wagon w9d+ up a /eep hill1 "o side ( ! road be+ m elevat$ ?an ! o!r2 let u suppose x to slope z is describ$ 9 ?is figure1 7plate #c4 fig4 #d47 we w say1 t ! c5tre ( gravity ( ?is load$ wagon is at ! po9t ,a4 ,n[ y\r eye w tell y1 t a wagon ?us situat$1 w ov]set2 & ! reason is1 t ! c5tre ( gravity ,a1 is n support$2 = if y draw a p]p5dicul> l9e f x to ! gr\nd at ,c1 x does n fall "u ! wagon )9 ! :eels1 & is !re=e n support$ by !m4 ,c>ol9e4 ,i und]/& t p]fectly2 b :at is ! mean+ ( ! o!r po9t ,b8 ,mrs4 ,b4 ,let u1 9 imag9ation take (f ! upp] "p ( ! load2 ! c5tre ( gravity w !n *ange its situation1 & desc5d to ,b1 z t w n[ be ! po9t ab\t :i* ! p>ts ( ! less heavily lad5 wagon w balance ea* o!r4 ,w ! wagon n[ be upset8 ,c>ol9e4 ,no1 because a p]p5dicul> l9e f t po9t falls )9 ! :eels at ,d1 & is support$ by !m2 & :5 ! c5tre ( gravity is support$1 ! body w n fall4 ,emily4 ,yet ,i %\ld n mu* l to pass a wagon 9 t situation1 =1 z y see1 ! po9t ,d is b j )9 ! left :eel2 if ! "r :eel 0 rais$1 by m]ely pass+ ov] a /one1 ! po9t ,d w\ld be ?r[n on ! outside ( ! left :eel1 & ! wagon w\ld upset4 ,c>ol9e4 ,a wagon1 or any c>riage :atev]1 w !n be mo/ firmly support$1 :5 ! c5tre ( gravity falls exactly betwe5 ! :eels2 & t is ! case 9 a level road4 ,mrs4 ,b4 ,! c5tre ( gravity ( ! human body1 is a po9t some:]e 9 a l9e ext5d+ p]p5dicul>ly ?r\gh ! middle ( x1 & z long z we /& upright1 ?is po9t is support$ by ! feet2 if y lean on "o side1 y w f9d t y no long] /& firm4 ,a rope-danc] p]=ms all 8 feats ( agility1 by dext]\sly support+ 8 c5tre ( gravity2 :5ev] he f9ds t he is 9 dang] ( los+ 8 balance1 he %ifts ! heavy pole :i* he holds 9 8 h&s1 9 ord] to ?r[ ! weight t[>ds ! side t is defici5t2 & ?us by *ang+ ! situation ( ! c5tre ( gravity1 he re/ores 8 equilibrium4 ,c>ol9e4 ,:5 a /ick is pois$ on ! tip ( ! f+]1 is x n by support+ its c5tre ( gravity8 ,mrs4 ,b4 ,yes2 & x is because ! c5tre ( gravity is n support$1 t sph]ical bodies roll d[n a slope4 ,a sph]e be+ p]fectly r\nd1 c t\* ! slope b by a s+le po9t1 & t po9t _c be p]p5dicul>ly "u ! c5tre ( gravity1 & !re=e _c be support$1 z y w p]ceive by exam9+ ?is figure4 7fig4 #e4 plate #c47 ,emily4 ,s x appe>s3 yet ,i h se5 a cyl9d] ( wood roll up a slope2 h[ is t contriv$8 ,mrs4 ,b4 ,x is done by plugg+ or load+ "o side ( ! cyl9d] ) lead1 z at ,b1 7fig4 #e4 plate #c47 ! body be+ no long] ( a uni=m d5sity1 ! c5tre ( gravity is remov$ f ! middle ( ! body to "s po9t 9 or ne> ! lead1 z t sub/ance is mu* heavi] ?an wood2 n[ y may obs]ve t %\ld ?is cyl9d] roll d[n ! plane1 z x is "h situat$1 ! c5tre ( gravity mu/ rise1 :i* is impossible2 ! c5tre ( gravity mu/ always desc5d 9 mov+1 & w desc5d by ! ne>e/ & readie/ means1 :i* w be by =c+ ! cyl9d] up ! slope1 until ! c5tre ( gravity is support$1 & !n x /ops4 ,c>ol9e4 ,! c5tre ( gravity1 !re=e1 is n always 9 ! middle ( a body4 ,mrs4 ,b4 ,no1 t po9t we h call$ ! c5tre ( magnitude2 :5 ! body is ( an uni=m d5sity1 & ( a regul> =m1 z a cube1 or sph]e1 ! c5tres ( gravity & ( magnitude are 9 ! same po9t2 b :5 "o "p ( ! body is compos$ ( heavi] mat]ials ?an ano!r1 ! c5tre ( gravity c no long] correspond ) ! c5tre ( magnitude4 ,?us y see ! c5tre ( gravity ( ?is cyl9d] plugg$ ) lead1 _c be 9 ! same spot z ! c5tre ( magnitude4 ,emily4 ,bodies1 !re=e1 consi/+ b ( "o k9d ( sub/ance1 z wood1 /one1 or lead1 & ^: d5sities are consequ5tly uni=m1 mu/ /& m firmly1 & be m difficult to ov]set1 ?an bodies compos$ ( a v>iety ( sub/ances1 ( diff]5t d5sities1 :i* may ?r[ ! c5tre ( gravity on "o side4 ,mrs4 ,b4 ,t dep5ds ^u ! situation ( ! mat]ials2 if ^? :i* are mo/ d5se1 occupy ! l[] "p1 ! /ability w be increas$1 z ! c5tre ( gravity w be ne> ! base4 ,b !re is ano!r circum/ance :i* m mat]ially affects ! firmness ( _! position1 & t is _! =m4 ,bodies t h a n>r[ base are easily upset1 = if !y are a little incl9$1 _! c5tre ( gravity is no long] support$1 z y may p]ceive 9 fig4 #f4 ,c>ol9e4 ,i h (t5 obs]v$ ) :at difficulty a p]son c>ries a s+le pail ( wat]2 x is ow+1 ,i suppose1 to ! c5tre ( gravity be+ ?r[n on "o side2 & ! opposite arm is /ret*$ out to endeav\r to br+ x back to its orig9al situation2 b a pail hang+ to ea* arm is c>ri$ ) less difficulty1 because !y balance ea* o!r1 & ! c5tre ( gravity rema9s support$ by ! feet4 ,mrs4 ,b4 ,v well2 ,i h b "o m rem>k to make on ! c5tre ( gravity1 :i* is1 t :5 two bodies are fa/5$ toge!r by an inflexible rod1 !y are to be consid]$ z =m+ b "o body2 if ! two bodies be ( equal weight1 ! c5tre ( gravity w be 9 ! middle ( ! l9e :i* unites !m1 7fig4 #g47 b if "o be heavi] ?an ! o!r1 ! c5tre ( gravity w be proportionally ne>] ! heavy body ?an ! light "o4 7fig4 #h47 ,if y 7 to c>ry a rod or pole ) an equal weight fa/5$ at ea* end ( x1 y w\ld hold x 9 ! middle ( ! rod1 9 ord] t ! weights %\ld balance ea* o!r2 :il/ if ! weights 7 unequal1 y w\ld hold x ne>e/ ! great] weight1 to make !m balance ea* o!r4 ,emily4 ,& 9 bo? cases we %\ld support ! c5tre ( gravity2 & if "o weight be v consid]ably l>g] ?an ! o!r1 ! c5tre ( gravity w be ?r[n out ( ! rod into ! heavie/ weight4 7fig4 #i47 ,mrs4 ,b4 ,und\bt$ly4 ,que/ions #a4 7,pg4 #df7 ,if a body be /ruck by two equal =ces 9 opposite directions1 :at w be ! result8 #b4 7,pg4 #df7 ,:at is fig4 #e4 plate #b4 int5d$ to repres5t8 #c4 7,pg4 #dg7 ,h[ w\ld ! ball move1 & h[ w\ld y repres5t ! direction ( its motion8 #d4 7,pg4 #dg7 ,:at is suppos$ respect+ ! =ces repres5t$ 9 fig4 #f8 #e4 7,pg4 #dg7 ,h[ w\ld ! body move if s impell$8 #f4 7,pg4 #dg7 ,if ! =ces are unequal & n at "r angles1 h[ w\ld ! body move1 z illu/rat$ by fig4 #g8 #g4 7,pg4 #dg7 ,h[ mu/ a body be act$ on1 to produce motion 9 a curve1 & :at example is giv58 #h4 7,pg4 #dh7 ,:5 is a body said to revolve 9 a plane1 & :at is meant by ! c5tre ( motion8 #i4 7,pg4 #dh7 ,:at is int5d$ by ! axis ( motion1 & :at are examples8 #aj4 7,pg4 #dh7 ,:at is ! middle po9t ( a body call$8 #aa4 7,pg4 #dh7 ,:at is said ( ! axis ( motion1 :il/ ! body is revolv+8 #ab4 7,pg4 #dh7 ,:5 a body revolves on an axis1 d all its p>ts move ) equal velocity8 #ac4 7,pg4 #di7 ,h[ is ?is expla9$ by fig4 #a4 plate #c8 #ad4 7,pg4 #di7 ,:at are ! two =ces call$ :i* cause a body to move 9 a curve2 & :at proportion d ^! two =ces be> to ea* o!r :5 a body revolves r\nd a c5tre8 #ae4 7,pg4 #di7 ,if ! c5tripetal =ce 7 de/roy$1 h[ w\ld a body be c>ri$ by ! c5trifugal8 #af4 7,pg4 #ej7 ,expla9 :at is meant by a tang5t1 z %[n 9 fig4 #b4 plate #c4 #ag4 7,pg4 #ej7 ,:at =ces imp$e a body ?r[n horizontally8 #ah4 7,pg4 #ej7 ,give ! reason :y a body s project$1 falls 9 a curve4 7fig4 #c4 plate #c47 #ai4 7,pg4 #ea7 ,! curve 9 :i* x falls1 is n a "p ( a true circle3 :at is x d5om9at$8 #bj4 7,pg4 #ea7 ,:at is ! c5tre ( gravity def9$ to be8 #ba4 7,pg4 #ea7 ,:at results f support+1 or n support+ ! c5tre ( gravity8 #bb4 7,pg4 #ea7 ,:at is int5d$ to be expla9$ by fig4 #d4 plate #c8 #bc4 7,pg4 #ea7 ,:at w\ld be ! effect ( tak+ (f ! upp] portion ( ! load8 #bd4 7,pg4 #eb7 ,:5 w a c>riage /& mo/ firmly8 #be4 7,pg4 #eb7 ,:at is said ( ! c5tre ( gravity ( ! human body1 & h[ does a rope danc] pres]ve 8 equilibrium8 #bf4 7,pg4 #eb7 ,:y _c a sph]e rema9 at re/ on an incl9$ plane8 7fig4 #e4 plate #c47 #bg4 7,pg4 #eb7 ,a cyl9d] ( wood1 may be made to rise to a small di/ance up an incl9$ plane4 ,h[ may ?is be effect$8 7fig4 #e4 plate #c47 #bh4 7,pg4 #ec7 ,:5 d we f9d ! c5tres ( gravity1 & ( magnitude 9 diff]5t po9ts8 #bi4 7,pg4 #ec7 ,:at influ5ce w ! d5sity ( ! p>ts ( a body ex]t ^u its /ability8 #cj4 7,pg4 #ec7 ,:at o!r circum/ance mat]ially affects ! firmness ( position8 7fig4 #f4 plate #c47 #ca4 7,pg4 #ec7 ,:y is x m easy to c>ry a weight 9 ea* h&1 ?an 9 "o only8 #cb4 7,pg4 #ec7 ,:at is said respect+ two bodies unit$ by an inflexible rod8 #cc4 7,pg4 #ec7 ,:at is fig4 #g1 plate #c1 int5d$ to illu/rate8 ,:at fig4 #h2 :at fig4 #i8 ,,conv]sation ,v4 ,,on ,,! ,,me*anical ,,p[]s4 ,,( ,,! ,,p[] ,,( ,,ma*9es4 ,,( ,,! ,,lev] ,,9 ,,g5]al4 ,,( ,,! ,,lev] ,,( ,,! ,,fir/ ,,k9d1 ,,hav+ ,,! ,,fulcrum ,,betwe5 ,,! ,,p[] ,,& ,,! ,,weight4 ,,( ,,! ,,lev] ,,( ,,! ,,second ,,k9d1 ,,hav+ ,,! ,,weight ,,betwe5 ,,! ,,p[] ,,& ,,! ,,fulcrum4 ,,( ,,! ,,lev] ,,( ,,! ,,?ird ,,k9d1 ,,hav+ ,,! ,,p[] ,,betwe5 ,,! ,,fulcrum ,,& ,,! ,,weight4 ,,mrs4 ,b4 ,we may n[ proce$ to exam9e ! me*anical p[]s2 !y are six 9 numb]3 ,! lev]1 ! pulley1 ! :eel & axle1 ! incl9$ plane1 ! w$ge & ! screw2 "o or m ( :i* ent]s into ! composition ( e ma*9e4 ,a me*anical p[] is an in/rum5t by :i* ! effect ( a giv5 =ce is increas$1 :il/ ! =ce rema9s ! same4 ,9 ord] to und]/& ! p[] ( a ma*9e1 !re are f\r ?+s to be consid]$4 #a/4 ,! p[] t acts3 ?is consi/s 9 ! ef=t ( m5 or horses1 ( weights1 spr+s1 /eam1 c4 #b;dly4 ,! resi/ance :i* is to be ov]come by ! p[]3 ?is is g5]ally a weight to be mov$4 ,! p[] mu/ always be sup]ior to ! resi/ance1 o!rwise ! ma*9e c\ld n be put 9 motion4 ,c>ol9e4 ,if = in/ance ! resi/ance ( a c>riage 0 great] ?an ! /r5g? ( ! horses employ$ to draw x1 !y w\ld n be able to make x move4 ,mrs4 ,b4 #c;dly4 ,we are to consid] ! support or prop1 or z x is t]m$ 9 me*anics1 ! fulcrum2 ?is y may recollect is ! po9t ^u :i* ! body turns :5 9 motion2 & la/ly1 ! respective velocities ( ! p[]1 & ( ! resi/ance4 ,emily4 ,t mu/ 9 g5]al dep5d ^u _! respective di/ances f ! fulcrum1 or f ! axis ( motion2 z we obs]v$ 9 ! motion ( ! vanes ( ! w9dmill4 ,mrs4 ,b4 ,we %all n[ exam9e ! p[] ( ! lev]4 ,! lev] is an inflexible rod or b>1 moveable ab\t a fulcrum1 & hav+ =ces appli$ to two or m po9ts on x4 ,= in/ance1 ! /eel rod to :i* ^! scales are susp5d$ is a lev]1 & ! po9t 9 :i* x is support$1 ! fulcrum1 or c5tre ( motion2 n[1 c y tell me :y ! two scales are 9 equilibrium8 ,c>ol9e4 ,be+ bo? empty1 & ( ! same weight1 !y balance ea* o!r4 ,emily4 ,or1 m correctly speak+1 because ! c5tre ( gravity common to bo?1 is support$4 ,mrs4 ,b4 ,v well2 & :]e is ! c5tre ( gravity ( ?is pair ( scales8 7fig4 #a4 plate #d47 ,emily4 ,y h told u t :5 two bodies ( equal weight 7 fa/5$ toge!r1 ! c5tre ( gravity 0 9 ! middle ( ! l9e t connect$ !m2 ! c5tre ( gravity ( ! scales mu/ !re=e be support$ by ! fulcrum ,f ( ! lev] :i* unites ! two scales1 & :i* is ! c5tre ( motion4 ,c>ol9e4 ,b if ! scales conta9$ diff]5t weights1 ! c5tre ( gravity w\ld no long] be 9 ! fulcrum ( ! lev]1 b remove t[>ds t scale :i* conta9$ ! heavie/ weight2 & s9ce t po9t w\ld no long] be support$1 ! heavy scale w\ld desc5d1 & out-weigh ! o!r4 ,mrs4 ,b4 ,true2 b tell me1 c y imag9e any mode by :i* bodies ( diff]5t weights c be made to balance ea* o!r1 ei!r 9 a pair ( scales1 or simply susp5d$ to ! extremities ( ! lev]8 = ! scales are n an ess5tial "p ( ! ma*9e2 !y h no me*anical p[]1 & are us$ m]ely = ! conv5i5ce ( conta9+ ! sub/ance to be weigh$4 ,c>ol9e4 ,:at6 make a light body balance a heavy "o8 ,i _c conceive t possible4 ,mrs4 ,b4 ,! fulcrum ( ?is pair ( scales 7fig4 #b47 is moveable1 y see2 ,i c take x (f ! beam1 & fa/5 x on aga9 9 ano!r "p2 ?is "p is n[ become ! fulcrum1 b x is no long] 9 ! c5tre ( ! lev]4 ,c>ol9e4 ,& ! scales are no long] true2 = t :i* hangs on ! longe/ side ( ! lev] desc5ds4 ,mrs4 ,b4 ,! two p>ts ( ! lev] divid$ by ! fulcrum1 are call$ its arms2 y %\ld !re=e say ! longe/ arm1 n ! longe/ side ( ! lev]4 ,y\r obs]vation is true t ! balance is n[ de/roy$2 b x w answ] ! purpose ( enabl+ y to compreh5d ! p[] ( a lev]1 :5 ! fulcrum is n 9 ! c5tre4 ,emily4 ,?is w\ld be an excell5t contrivance = ^? :o *eat 9 ! weight ( _! goods2 by mak+ ! fulcrum a little on "o side1 & plac+ ! goods 9 ! scale :i* is susp5d$ to ! longe/ arm ( ! lev]1 !y w\ld appe> to weigh m ?an !y d 9 reality4 ,mrs4 ,b4 ,y d n consid] h[ easily ! fraud w\ld be detect$2 = on ! scales be+ empti$ !y w\ld n hang 9 equilibrium4 ,if inde$ ! scale on ! %ort] arm 0 made heavi]1 s z to balance t on ! long]1 !y w\ld appe> to be true1 :il/ !y 7 really false4 ,emily4 ,true2 ,i did n ?9k ( t circum/ance4 ,b ,i d n und]/& :y ! longe/ arm ( ! lev] %\ld n be 9 equilibrium ) ! o!r8 ,c>ol9e4 ,x is because ! mom5tum 9 ! longe/1 is great] ?an 9 ! %orte/ arm2 ! c5tre ( gravity1 !re=e1 is no long] support$4 ,mrs4 ,b4 ,y are "r1 ! fulcrum is no long] 9 ! c5tre ( gravity2 b if we c contrive to make ! fulcrum 9 its pres5t situation become ! c5tre ( gravity1 ! scales w aga9 balance ea* o!r2 = y recollect t ! c5tre ( gravity is t po9t ab\t :i* e "p ( ! body is 9 equilibrium4 ,emily4 ,x has j occurr$ to me h[ ?is may be accompli%$2 put a great weight into ! scale susp5d$ to ! %orte/ arm ( ! lev]1 & a small] "o into t susp5d$ to ! longe/ arm4 ,yes1 ,i h discov]$ x--look ,mrs4 ,b41 ! scale on ! %orte/ arm w c>ry #c lbs41 & t on ! longe/ arm only "o1 to re/ore ! balance4 7fig4 #c47 ,mrs4 ,b4 ,y see1 !re=e1 t x is n s impracticable z y imag9$1 to make a heavy body balance a light "o2 & ?is is 9 fact ! means by :i* y obs]v$ t an imposition 9 ! weight ( goods might be effect$1 z a weight ( t5 or twelve ounces1 might ?us be made to balance a p\nd ( goods4 ,if y measure bo? arms ( ! lev]1 y w f9d t ! l5g? ( ! long] arm1 is ?ree times t ( ! %ort]2 & t to produce an equilibrium1 ! weights mu/ be> ! same proportion to ea* o!r1 & t ! great] weight1 mu/ be on ! %ort] arm4 ,let u n[ take (f ! scales1 t we may consid] ! lev] simply2 & 9 ?is /ate y see t ! fulcrum is no long] ! c5tre ( gravity1 because x has be5 remov$ f ! middle ( ! lev]2 b x is1 & mu/ ev] be1 ! c5tre ( motion1 z x is ! only po9t :i* rema9s at re/1 :ile ! o!r p>ts move ab\t x4 ,illu/ration3 ,,plate ,,iv4 ,c>ol9e4 ,! arms ( ! lev] be+ diff]5t 9 l5g?1 x n[ exactly resembles ! /eely>ds1 ) :i* articles are s frequ5tly weigh$4 ,mrs4 ,b4 ,x may 9 fact be consid]$ z a pair ( /eely>ds1 by :i* ! same p[] enables u to asc]ta9 ! weight ( diff]5t articles1 by simply increas+ ! di/ance ( ! p[] f ! fulcrum2 y "k t ! f>!r a body is f ! axis ( motion1 ! great] is its velocity4 ,c>ol9e4 ,t ,i rememb]1 & und]/& p]fectly4 ,mrs4 ,b4 ,y compreh5d !n1 t ! extremity ( ! longe/ arm ( a lev]1 mu/ move ) great] velocity ?an t ( ! %orte/ arm1 & t its mom5tum is great] 9 proportion4 ,emily4 ,no d\bt1 because x is f>!/ f ! c5tre ( motion4 ,& pray1 ,mrs4 ,b41 :5 my bro!rs play at see-saw1 is n ! plank on :i* !y ride1 a k9d ( lev]8 ,mrs4 ,b4 ,c]ta9ly2 ! log ( wood :i* supports x f ! gr\nd is ! fulcrum1 & ^? :o ride1 repres5t ! p[] & ! resi/ance at ! ends ( ! lev]4 ,& h y n obs]v$ t :5 ^? :o ride are ( equal weight1 ! plank mu/ be support$ 9 ! middle1 to make ! two arms equal2 :il/ if ! p]sons diff] 9 weight1 ! plank mu/ be drawn a little f>!r ov] ! prop1 to make ! arms unequal1 & ! lighte/ p]son1 :o may be suppos$ to repres5t ! p[]1 mu/ be plac$ at ! extremity ( ! longe/ arm4 ,c>ol9e4 ,t is always ! case :5 ,i ride on a plank ) my y\nge/ bro!r2 ,i h obs]v$ also t ! lighte/ p]son has ! be/ ride1 z he moves bo? fur!r & quick]2 & ,i n[ und]/& t x is because he is m di/ant f ! c5tre ( motion4 ,mrs4 ,b4 ,! great] velocity ) :i* y\r little bro!r moves1 r5d]s 8 mom5tum equal to y\rs4 ,c>ol9e4 ,yes2 ,i h ! mo/ weight1 he ! greate/ velocity2 s t ^u ! :ole our mom5tums are equal4 ,b y said1 ,mrs4 ,b41 t ! p[] %\ld be great] ?an ! resi/ance1 to put ! ma*9e 9 motion2 h[ !n c ! plank move if ! mom5tums ( ! p]sons :o ride are equal8 ,mrs4 ,b4 ,because ea* p]son at 8 desc5t t\*es & pu%es aga9/ ! gr\nd ) 8 feet2 ! reaction ( :i* gives him an impulse :i* produces ! motion2 ?is spr+ is requisite to de/roy ! equilibrium ( ! p[] & ! resi/ance1 o!rwise ! plank w\ld n move4 ,did y ev] obs]ve t a lev] describes ! arc ( a circle 9 its motion8 ,emily4 ,no2 x appe>s to me to rise & desc5d p]p5dicul>ly2 at lea/ ,i always ?\ght s4 ,mrs4 ,b4 ,i believe ,i mu/ make a sket* ( y & y\r bro!r rid+ on a plank1 9 ord] to conv9ce y ( y\r error4 7fig4 #d4 plate #d47 ,y may n[ obs]ve t a lev] c move only r\nd ! fulcrum1 s9ce t is ! c5tre ( motion2 x w\ld be impossible = y to rise p]p5dicul>ly1 to ! po9t ,a2 or = y\r bro!r to desc5d 9 a /raight l9e1 to ! po9t ,b2 y mu/ 9 ris+1 & he 9 desc5d+1 describe arcs ( y\r respective circles4 ,?is draw+ %[s y also h[ mu* sup]ior 8 velocity mu/ be to y\rs2 = if y c\ld sw+ q r\nd1 y w\ld ea* complete y\r respective circles1 9 ! same "t4 ,c>ol9e4 ,my bro!r's circle be+ mu* ! l>ge/1 he mu/ und\bt$ly move ! quicke/4 ,mrs4 ,b4 ,n[ tell me1 d y ?9k t y\r bro!r c\ld raise y z easily )\t ! aid ( a lev]8 ,c>ol9e4 ,oh no1 he c\ld n lift me (f ! gr\nd4 ,mrs4 ,b4 ,!n ,i ?9k y require no fur!r pro( ( ! p[] ( a lev]1 s9ce y see :at x enables y\r bro!r to p]=m4 ,c>ol9e4 ,i n[ und]/& :at y meant by say+1 t 9 me*anics1 velocity is oppos$ to weight1 = x is my bro!r's velocity :i* ov]comes my weight4 ,mrs4 ,b4 ,y may easily imag9e1 :at enorm\s weights may be rais$ by lev]s ( ?is description1 = ! long]1 :5 comp>$ ) ! o!r1 t arm is to :i* ! p[] is appli$1 ! great] w be ! effect produc$ by x2 because ! great] is ! velocity ( ! p[] comp>$ to t ( ! weight4 ,lev]s are ( ?ree k9ds2 9 ! fir/ ! fulcrum is betwe5 ! p[] & ! weight4 ,c>ol9e4 ,?is k9d !n compreh5ds ! sev]al lev]s y h describ$4 ,mrs4 ,b4 ,yes1 :5 9 lev]s ( ! fir/ k9d1 ! fulcrum is equally di/ant f ! p[] & ! weight1 z 9 ! balance1 !re w be an equilibrium1 :5 ! p[] & ! weight are equal to ea* o!r2 x is n !n a me*anical p[]1 = no?+ c 9 ?is case be ga9$ by velocity2 ! two arms ( ! lev] be+ equal1 ! velocity ( _! extremities mu/ be s likewise4 ,! balance is !re=e ( no assi/ance z a me*anical p[]1 al?\gh x is extremely useful 9 e/imat+ ! respective weights ( bodies4 ,b :5 7fig4 #e47 ! fulcrum ,f ( a lev] is n equally di/ant f ! p[] & ! weight1 & ! p[] ,p acts at ! extremity ( ! longe/ arm1 x may be less ?an ! weight ,w2 its defici5cy be+ comp5sat$ by its sup]ior velocity1 z we obs]v$ 9 ! see-saw4 ,emily4 ,!n :5 we want to lift a great weight1 we mu/ fa/5 x to ! %orte/ arm ( a lev]1 & apply our /r5g? to ! longe/ arm8 ,mrs4 ,b4 ,if ! case w admit ( y\r putt+ ! end ( ! lev] "u ! resi/+ body1 no fa/5+ w be requir$2 z y w p]ceive1 :5 a nail is drawn by means ( a hamm]1 :i*1 ?\gh b5t1 is a lev] ( ! fir/ k9d2 ! h&le be+ ! longe/ arm1 ! po9t on :i* x re/s1 ! fulcrum1 & ! di/ance f t to ! "p :i* holds ! nail1 ! %ort arm4 ,b let me he>1 ,c>ol9e1 :e!r y c expla9 ! action ( ?is in/rum5t1 :i* is compos$ ( two lev]s unit$ 9 "o common fulcrum4 ,c>ol9e4 ,a pair ( scissors6 ,mrs4 ,b4 ,y are surpris$2 b if y exam9e _! con/ruction1 y w discov] t x is ! p[] ( ! lev]1 t assi/s u 9 cutt+ ) scissors4 ,c>ol9e4 ,yes2 ,i n[ p]ceive t ! po9t at :i* ! two lev]s are screw$ toge!r1 is ! fulcrum2 ! p[] ( ! f+]s is appli$ to ! h&les1 & ! article to be cut1 is ! resi/ance2 !re=e1 ! long] ! h&les1 & ! %ort] ! po9ts ( ! scissors1 ! m easily y cut ) !m4 ,emily4 ,t ,i h (t5 obs]v$1 = :5 ,i cut pa/e-bo>d or any h>d sub/ance1 ,i always make use ( t "p ( ! scissors ne>e/ ! screw or rivet1 & ,i n[ und]/& :y x increases ! p[] ( cutt+2 b ,i confess t ,i nev] %\ld h discov]$ scissors to h be5 d\ble lev]s2 & pray are n snuff]s lev]s ( a simil> description8 ,mrs4 ,b4 ,yes1 & mo/ k9ds ( p9c]s2 ! great p[] ( :i* consi/s 9 ! great relative l5g? ( ! h&les4 ,did y ev] notice ! sw+le-tree ( a c>riage to :i* ! horses are atta*$ :5 draw+8 ,emily4 ,o yes2 ?is is a lev] ( ! fir/ k9d1 b ! fulcrum be+ 9 ! middle1 ! horses %\ld draw ) equal p[]1 :atev] may be _! /r5g?4 ,mrs4 ,b4 ,t is g5]ally ! case1 b x is evid5t t by mak+ "o arm long] ?an ! o!r1 x might be adapt$ to horses ( unequal /r5g?4 ,c>ol9e4 ,& ( :at nature are ! o!r two k9ds ( lev]s8 ,mrs4 ,b4 ,9 lev]s ( ! second k9d1 ! weight1 in/ead ( be+ at "o end1 is situat$ betwe5 ! p[] & ! fulcrum1 7fig4 #f47 ,c>ol9e4 ,! weight & ! fulcrum h "h *ang$ places2 & :at advantage is ga9$ by ?is k9d ( lev]8 ,mrs4 ,b4 ,9 mov+ x1 ! velocity ( ! p[] mu/ necess>ily be great] ?an t ( ! weight1 z x is m di/ant f ! c5tre ( ! motion4 ,h y ev] se5 y\r bro!r move a sn[-ball by means ( a /rong /ick1 :5 x became too heavy = him to move )\t assi/ance8 ,c>ol9e4 ,oh yes2 & ?is 0 a lev] ( ! second k9d1 7fig4 #g47 ! end ( ! /ick1 :i* he ?ru/s "u ! ball1 & :i* re/s on ! gr\nd1 becomes ! fulcrum2 ! ball is ! weight to be mov$1 & ! p[] 8 h&s1 appli$ to ! o!r end ( ! lev]4 ,9 ?is in/ance !re is a great diff]5ce 9 ! l5g? ( ! arms ( ! lev]2 = ! weight is almo/ close to ! fulcrum4 ,mrs4 ,b4 ,& ! advantage ga9$ is proportional to ?is diff]5ce4 ,! mo/ common example t we h ( lev]s ( ! second k9d1 is 9 ! doors ( our ap>tm5ts4 ,emily4 ,! h+es repres5t ! fulcrum1 our h&s ! p[] appli$ to ! o!r end ( ! lev]2 b :]e is ! weight to be mov$8 ,mrs4 ,b4 ,! door is ! weight1 :i* 9 ?is example occupies ! :ole ( ! space betwe5 ! p[] & ! fulcrum4 ,nut crack]s are d\ble lev]s ( ?is k9d3 ! h+e is ! fulcrum1 ! nut ! resi/ance1 & ! h&s ! p[]4 ,9 lev]s ( ! ?ird k9d 7fig4 #h47 ! fulcrum is aga9 at "o extremity1 ! weight or resi/ance at ! o!r1 & ! p[] is appli$ betwe5 ! fulcrum & ! resi/ance4 ,emily4 ,! fulcrum1 ! weight1 or ! p[]1 !n1 ea* 9 its turn1 occupies "s "p ( ! lev] betwe5 its extremities4 ,b 9 ?is ?ird k9d ( lev]1 ! weight be+ f>!r ?an ! p[] f ! c5tre ( motion1 ! difficulty ( rais+ x seems increas$ r ?an dim9i%$4 ,mrs4 ,b4 ,t is v true2 a lev] ( ?is k9d is !re=e nev] us$1 unless absolutely necess>y1 z is ! case 9 rais+ a ladd] 9 ord] to place x aga9/ a wall2 ! man :o raises x _c place 8 h&s on ! upp] "p ( ! ladd]1 ! p[]1 !re=e1 is necess>ily plac$ mu* ne>] to ! fulcrum ?an to ! weight4 ,c>ol9e4 ,yes1 ! h&s are ! p[]1 ! gr\nd ! fulcrum1 & ! upp] "p ( ! ladd] ! weight4 ,mrs4 ,b4 ,nature employs ?is k9d ( lev] 9 ! /ructure ( ! human frame4 ,9 lift+ a weight ) ! h&1 ! l[] "p ( ! arm becomes a lev] ( ! ?ird k9d2 ! elb[ is ! fulcrum1 ! muscles ( ! fle%y "p ( ! arm1 ! p[]2 & z ^! are ne>] to ! elb[ ?an to ! h&1 x is necess>y t _! p[] %\ld exce$ ! weight to be rais$4 ,emily4 ,is x n surpris+ t nature %\ld h furni%$ u ) su* disadvantage\s lev]s8 ,mrs4 ,b4 ,! disadvantage1 9 respect to p[]1 is m ?an c\nt]balanc$ by ! conv5i5ce result+ f ?is /ructure ( ! arm2 & x is t no d\bt :i* is be/ adapt$ to enable x to p]=m its v>i\s functions4 ,!re is "o rule :i* applies to e lev]1 :i* is ?is3 ,9 ord] to produce an equilibrium1 ! p[] mu/ be> ! same proportion to ! weight1 z ! l5g? ( ! %ort] arm does to t ( ! long]2 z 0 %[n by ,emily ) ! weights ( #a lb4 & ( #c lb4 ,fig4 #c4 plate #d4 ,we h dwelt s long on ! lev]1 t we mu/ res]ve ! exam9ation ( ! o!r me*anical p[]s1 to our next int]view4 ,que/ions #a4 7,pg4 #ed7 ,h[ _m me*anical p[]s are !re1 & :at are !y nam$8 #b4 7,pg4 #ed7 ,:at is a me*anical p[] def9$ to be8 #c4 7,pg4 #ed7 ,:at f\r p>ticul>s mu/ be obs]v$8 #d4 7,pg4 #ed7 ,^u :at w ! velocities dep5d8 #e4 7,pg4 #ee7 ,:at is a lev]8 #f4 7,pg4 #ee7 ,give a famili> example4 #g4 7,pg4 #ee7 ,:5 & :y d ! scales balance ea* o!r1 & :]e is _! c5tre ( gravity8 7fig4 #a4 plate #d47 #h4 7,pg4 #ee7 ,:y w\ld !y n balance ) unequal weights8 #i4 7,pg4 #ee7 ,7 ! fulcrum remov$ f ! middle ( ! beam :at w\ld result8 #aj4 7,pg4 #ee7 ,:at d we mean by ! arms ( a lev]8 #aa4 7,pg4 #ef7 ,h[ may a pair ( scales be false1 & yet appe> to be true8 #ab4 7,pg4 #ef7 ,if ! fulcrum be remov$ f ! c5tre ( gravity1 h[ may ! equilibrium be re/or$8 #ac4 7,pg4 #ef7 ,h[ is ?is exemplifi$ by fig4 #c4 plate #d8 #ad4 7,pg4 #ef7 ,:at proportion mu/ ! weights be> to ! l5g?s ( ! arms8 #ae4 7,pg4 #eg7 ,on :at pr9ciple d we weigh ) a pair ( /eely>ds1 & :at w be ! diff]5ce 9 ! motion ( ! extremities ( su* a lev]8 #af4 7,pg4 #eh7 ,h[ is ?is exemplifi$ by fig4 #d4 plate #d8 #ag4 7,pg4 #eh7 ,:at l9e is describ$ by ! ends ( a lev]8 fig4 #d4 plate #d4 #ah4 7,pg4 #eh7 ,h[ _m k9ds are !re2 & 9 ! fir/ h[ is ! fulcrum situat$8 #ai4 7,pg4 #eh7 ,:5 may ! fulcrum be s situat$ t ?is lev] is n a me*anical p[]1 & :y8 #bj4 7,pg4 #ei7 ,:at is repres5t$ by fig4 #e4 plate #d8 #ba4 7,pg4 #ei7 ,give a famili> example ( ! use ( a lev] ( ! fir/ k9d4 #bb4 7,pg4 #ei7 ,9 :at in/rum5ts are two su* lev]s comb9$8 #bc4 7,pg4 #ei7 ,h[ may two horses ( unequal /r5g?1 be advantage\sly c\pl$ 9 a c>riage8 #bd4 7,pg4 #fj7 ,describe a lev] ( ! second k9d4 7,fig4 #f4 plate #d47 #be4 7,pg4 #fj7 ,:at is repres5t$ 9 fig4 #g4 plate #d1 & 9 :at proportion does ?is lev] ga9 p[]8 #bf4 7,pg4 #fj7 ,:at is said respect+ a door8 #bg4 7,pg4 #fj7 ,describe a lev] ( ! ?ird k9d4 #bh4 7,pg4 #fj7 ,9 :at in/ance d we use ?is8 #bi4 7,pg4 #fa7 ,:at rem>ks are made on its employm5t 9 ! limbs ( animals8 #cj4 7,pg4 #fa7 ,:at are ! conditions ( equilibrium 9 e lev]8 ,,conv]sation ,v4 ,,cont9u$4 ,,on ,,! ,,me*anical ,,p[]s4 ,,( ,,! ,,pulley4 ,,( ,,! ,,:eel ,,& ,,axle4 ,,( ,,! ,,incl9$ ,,plane4 ,,( ,,! ,,w$ge4 ,,( ,,! ,,screw4 ,,mrs4 ,b4 ,! pulley is ! second me*anical p[] we are to exam9e4 ,y bo?1 ,i suppose1 h se5 a pulley8 ,c>ol9e4 ,yes1 frequ5tly3 x is a circul>1 & flat piece ( wood or metal1 ) a /r+ :i* runs 9 a groove r\nd x3 by means ( :i*1 a weight may be pull$ up2 ?us pulleys are us$ = draw+ up curta9s4 ,mrs4 ,b4 ,yes2 b 9 t in/ance ! pulleys are fix$2 t is1 !y reta9 _! places1 & m]ely turn r\nd on _! axis2 ^! d n increase ! p[] to raise ! weights1 z y w p]ceive by ?is figure4 7plate #e4 fig4 #a47 ,obs]ve t ! fix$ pulley is on ! same pr9ciple z ! lev] ( a pair ( scales1 9 :i* ! fulcrum ,f be+ 9 ! c5tre ( gravity1 ! p[] ,p & ! weight ,w1 are equally di/ant f x1 & no advantage is ga9$4 ,emily4 ,c]ta9ly2 if ,p repres5ts ! p[] employ$ to raise ! weight ,w1 ! p[] mu/ be great] ?an ! weight 9 ord] to move x4 ,b ( :at use !n is a fix$ pulley 9 me*anics8 ,mrs4 ,b4 ,al?\gh x does n increase ! p[]1 x is frequ5tly useful = alt]+ its direction4 ,a s+le fix$ pulley enables u to draw a curta9 up1 by pull+ ! /r+ connect$ ) x d[nw>ds2 & we %\ld be at a loss to accompli% ?is simple op]ation )\t its assi/ance4 ,c>ol9e4 ,!re w\ld c]ta9ly be "s difficulty 9 asc5d+ to ! head ( ! curta91 9 ord] to draw x up4 ,inde$ ,i n[ recollect hav+ se5 workm5 raise weights to a consid]able height by means ( a fix$ pulley1 :i* sav$ !m ! tr\ble ( go+ up !mselves4 ,mrs4 ,b4 ,! next figure repres5ts a pulley :i* is n fix$2 7fig4 #b47 & ?us situat$1 y w p]ceive t x af=ds u me*anical assi/ance4 ,a is a moveable pulley2 t is1 "o :i* is atta*$ to ! weight to be rais$1 & :i* consequ5tly moves up or d[n ) x4 ,!re is also a fix$ pulley ,d1 :i* is only ( use to *ange ! direction ( ! p[] ,p4 ,n[ x is evid5t t ! velocity ( ! p[]1 w be d\ble t ( ! weight ,w2 = if ! rope be pull$ at ,p1 until ! pulley ,a asc5ds ) ! weight to ! fix$ pulley ,d1 !n bo? p>ts ( ! rope1 ,c & ,b1 mu/ pass ov] ! fix$ pulley1 & consequ5tly ! h& at ,p1 w h desc5d$ ?r\gh a space equal to ^? two p>ts2 b ! weight w h asc5d$ only "o half ( t di/ance4 ,c>ol9e4 ,t ,i und]/&3 if ,p drew ! /r+ b "o in*1 ! weight w\ld be rais$ only half an in*1 because x w\ld %ort5 ! /r+s ,b & ,c half an in* ea*1 & consequ5tly ! pulley ) ! weight atta*$ to x1 c be rais$ only half an in*4 ,emily4 ,b ,i d n yet und]/& ! advantage ( moveable pulleys2 !y seem to me to increase r ?an dim9i% ! difficulty ( rais+ weights1 s9ce y mu/ draw ! /r+ d\ble ! l5g? t y raise ! weight2 :il/ ) a s+le pulley1 or )\t any pulley1 ! weight is rais$ z mu* z ! /r+ is %ort5$4 ,mrs4 ,b4 ,! advantage ( a moveable pulley consi/s 9 divid+ ! difficulty2 we mu/1 x is true1 draw twice ! l5g? ( ! /r+1 b !n only half ! /r5g? is requir$ t w\ld be necess>y to raise ! weight )\t ! assi/ance ( a moveable pulley4 ,emily4 ,s t ! difficulty is ov]come 9 ! same mann] z x w\ld be1 by divid+ ! weight into two equal p>ts1 & rais+ !m successively4 ,mrs4 ,b4 ,exactly4 ,y mu/ obs]ve1 t ) a moveable pulley ! velocity ( ! p[]1 is d\ble t ( ! weight2 s9ce ! p[] ,p 7fig4 #b47 moves two in*es :il/ ! weight ,w moves "o in*2 !re=e ! p[] ne$ n be m ?an half ! weight1 to make _! mom5tums equal4 ,c>ol9e4 ,pulleys act !n on ! same pr9ciple z ! lev]2 ! defici5cy ( weight 9 ! p[]1 be+ comp5sat$ by its sup]ior velocity1 s z to make _! mom5tums equal4 ,mrs4 ,b4 ,y w f9d1 t all ga9 ( p[] 9 me*anics is f\nd$ on ! same pr9ciple4 ,emily4 ,b may x n be object$ to pulleys1 t a long] "t is requir$ to raise a weight by _! aid1 ?an )\t x8 = :at y ga9 9 p[]1 y lose 9 "t4 ,mrs4 ,b4 ,t1 my de>1 is ! fundam5tal law 9 me*anics3 x is ! case ) ! lev]1 z well z ! pulley2 & y w f9d x to be s ) all ! o!r me*anical p[]s4 ,c>ol9e4 ,i d n see any advantage 9 ! me*anical p[]s !n1 if :at we ga9 by !m 9 "o way1 is lo/ 9 ano!r4 ,mrs4 ,b4 ,s9ce we are n able to increase our natural /r5g? is n any in/rum5t ( obvi\s utility1 by means ( :i* we may r$uce ! resi/ance or weight ( any body1 to ! level ( t /r5g?8 ,?is ! me*anical p[]s enable u to accompli%4 ,x is true1 z y obs]ve1 t x requires a sacrifice ( "t to atta9 ?is end1 b y mu/ be s5sible h[ v advantage\sly x is ex*ang$ = p[]4 ,if "o man by 8 natural /r5g? c\ld raise "o hundr$ p\nds only1 x w\ld require five su* m5 to raise five hundr$ p\nds2 & if "o man p]=ms ?is by ! help ( a suitable eng9e1 !re is !n no actual loss ( "t2 z he does ! "w ( five m51 al?\gh he is five times z long 9 its accompli%m5t4 ,y c n[ und]/&1 t ! great] ! numb] ( moveable pulleys connect$ by a /r+1 ! m easily ! weight is rais$2 z ! difficulty is divid$ among/ ! numb] ( /r+s1 or r ( p>ts into :i* ! /r+ is divid$1 by ! pulleys4 ,two1 or m pulleys ?us connect$1 =m :at is call$ a tackle1 or sy/em ( pulleys4 7fig4 #c47 ,y may h se5 !m susp5d$ f cranes to raise goods into w>eh\ses4 ,emily4 ,:5 !re are two moveable pulleys1 z 9 ! figure y h %[n to u1 7fig4 #c47 !re mu/ also be two fix$ pulleys1 = ! purpose ( *ang+ ! direction ( ! /r+1 & !n ! weight is support$ by f\r /r+s1 & ( c\rse1 ea* mu/ be> only "o f\r? "p ( ! weight4 ,mrs4 ,b4 ,y are p]fectly correct1 & ! rule = e/imat+ ! p[] ga9$ by a sy/em ( pulleys1 is to c\nt ! numb] ( /r+s by :i* ! weight is support$2 or1 :i* am\nts to ! same ?+1 to multiply ! numb] ( moveable pulleys by two4 ,9 %ipp+1 ! advantages ( bo? an increase ( p[]1 & a *ange ( direction1 by means ( pulleys1 are ( ess5tial importance3 = ! sails are rais$ up ! ma/s by ! sailors on deck1 f ! *ange ( direction :i* ! pulley effects1 & ! lab\r is facilitat$ by ! me*anical p[] ( a comb9ation ( pulleys4 ,illu/ration3 ,,plate ,v4 ,emily4 ,b ! pulleys on %ip-bo>d d n appe> to me to be unit$ 9 ! mann] y h %[n u4 ,mrs4 ,b4 ,!y are1 ,i believe1 g5]ally connect$ z describ$ 9 figure #d1 bo? = nautical1 & a v>iety ( o!r purposes2 b 9 :atev] mann] pulleys are connect$ by a s+le /r+1 ! me*anical p[] is ! same4 ,! ?ird me*anical p[]1 is ! :eel & axle4 ,let u suppose 7plate #f4 fig4 #e7 ! weight ,w1 to be a bucket ( wat] 9 a well1 :i* we raise by w9d+ r\nd ! axle ! rope1 to :i* x is atta*$2 if ?is be done )\t a :eel to turn ! axle1 no me*anical assi/ance is receiv$4 ,! axle )\t a :eel is z impot5t z a s+le fix$ pulley1 or a lev]1 ^: fulcrum is 9 ! c5tre3 b add ! :eel to ! axle1 & y w imm$iately f9d ! bucket is rais$ ) mu* less difficulty4 ,! velocity ( ! circumf]5ce ( ! :eel is z mu* great] ?an t ( ! axle1 z x is fur!r f ! c5tre ( motion2 = ! :eel describes a great circle 9 ! same space ( "t t ! axle describes a small "o1 !re=e ! p[] is increas$ 9 ! same proportion z ! circumf]5ce ( ! :eel is great] ?an t ( ! axle4 ,if ! velocity ( ! :eel is twelve times great] ?an t ( ! axle1 a p[] twelve times less ?an ! weight ( ! bucket1 w\ld balance x2 & a small increase w\ld raise x4 ,emily4 ,! axle acts ! "p ( ! %ort] arm ( ! lev]1 ! :eel t ( ! long] arm4 ,c>ol9e4 ,9 rais+ wat]1 !re is commonly1 ,i believe1 in/ead ( a :eel atta*$ to ! axle1 only a crook$ h&le1 :i* answ]s ! purpose ( w9d+ ! rope r\nd ! axle1 & ?us rais+ ! bucket4 ,mrs4 ,b4 ,9 ?is mann] 7fig4 #f27 n[ if y obs]ve ! dott$ circle :i* ! h&le describes 9 w9d+ up ! rope1 y w p]ceive t ! bran* ( ! h&le ,a1 :i* is unit$ to ! axle1 repres5ts ! spoke ( a :eel1 & answ]s ! purpose ( an entire :eel2 ! o!r bran* ,b af=ds no me*anical aid1 m]ely s]v+ z a h&le to turn ! :eel4 ,:eels are a v ess5tial "p ( mo/ ma*9es2 !y are employ$ 9 v>i\s ways2 b1 :5 fix$ to ! axle1 _! me*anical p[] is always ! same3 t is1 z ! circumf]5ce ( ! :eel exce$s t ( ! axle1 s mu* w ! en]gy ( ! p[] be increas$4 ,c>ol9e4 ,!n ! l>g] ! :eel1 9 proportion to ! axle1 ! great] mu/ be its effect8 ,mrs4 ,b4 ,c]ta9ly4 ,if y h ev] se5 any consid]able mills or manufactures1 y mu/ h admir$ ! imm5se :eel1 ! revolution ( :i* puts ! :ole ( ! ma*9]y into motion2 & ?\gh s great an effect is produc$ by x1 a horse or two has suffici5t p[] to turn x2 sometimes a /ream ( wat] is us$ = t purpose1 b ( late ye>s1 a /eam-eng9e has be5 f\nd bo? ! mo/ p[]ful & ! mo/ conv5i5t mode ( turn+ ! :eel4 ,c>ol9e4 ,d n ! vanes ( a w9dmill repres5t a :eel1 ,mrs4 ,b48 ,mrs4 ,b4 ,yes2 & 9 ?is in/ance we h ! advantage ( a gratuit\s =ce1 ! w9d1 to turn ! :eel4 ,"o ( ! great b5efits result+ f ! use ( ma*9]y is1 t x gives u a sort ( empire ov] ! p[]s ( nature1 & enables u to make !m p]=m ! lab\r :i* w\ld o!rwise fall to ! lot ( man4 ,:5 a curr5t ( w9d1 a /ream ( wat]1 or ! expansive =ce ( /eam1 p]=ms our task1 we h only to sup]9t5d & regulate _! op]ations4 ,! f\r? me*anical p[] is ! incl9$ plane2 ?is is g5]ally no?+ m ?an a plank plac$ 9 a slop+ direction1 :i* is frequ5tly us$ to facilitate ! rais+ ( weights1 to a small height1 su* z ! roll+ ( hog%eads or b>rels into a w>eh\se4 ,x is n difficult to und]/&1 t a weight may mu* m easily be roll$ up a slope ?an x c be rais$ ! same height p]p5dicul>ly4 ,b 9 ?is1 z well z ! o!r me*anical p[]s1 ! facility is pur*as$ by a loss ( "t 7fig4 #g27 = ! weight1 in/ead ( mov+ directly f ,a to ,c1 mu/ move f ,b to ,c1 & z ! l5g? ( ! plane is to its height1 s mu* is ! resi/ance ( ! weight dim9i%$4 ,emily4 ,yes2 = ! resi/ance1 in/ead ( be+ conf9$ to ! %ort l9e ,a ,c1 is spread ov] ! long l9e ,b ,c4 ,mrs4 ,b4 ,! w$ge1 :i* is ! next me*anical p[]1 is usually view$ z compos$ ( two incl9$ planes 7fig4 #h37 y may h se5 wood-cutt]s use x to cleave wood4 ,! resi/ance consi/s 9 ! cohesive attraction ( ! wood1 or any o!r body :i* ! w$ge is employ$ to sep>ate2 ! advantage ga9$ by ?is p[] is diff]5tly e/imat$ by philosoph]s2 b "o ?+ is c]ta91 its p[] is increas$1 9 proportion to ! decrease ( its ?ickness1 comp>$ ) its l5g?4 ,! w$ge is a v p[]ful in/rum5t1 b x is always driv5 =w>d by bl[s f a hamm]1 or "s o!r body hav+ consid]able mom5tum4 ,emily4 ,! w$ge1 !n1 is r a comp\nd ?an a di/9ct me*anical p[]1 s9ce x is n propell$ by simple pressure1 or weight1 l ! o!r p[]s4 ,mrs4 ,b4 ,x is s4 ,all cutt+ in/rum5ts are con/ruct$ ^u ! pr9ciple ( ! incl9$ plane1 or ! w$ge3 ^? t h b "o edge slop$1 l ! *isel1 may be ref]r$ to ! incl9$ plane2 :il/ ! axe1 ! hat*et1 & ! knife1 7:5 us$ to split asund]7 are us$ z w$ges4 ,c>ol9e4 ,b a knife cuts be/ :5 x is drawn across ! sub/ance x is to divide4 ,we use x ?us 9 cutt+ meat1 we d n *op x to pieces4 ,mrs4 ,b4 ,! reason ( ?is is1 t ! edge ( a knife is really a v f9e saw1 & !re=e acts be/ :5 us$ l t in/rum5t4 ,! screw1 :i* is ! la/ me*anical p[]1 is m complicat$ ?an ! o!rs4 ,y w see by ?is figure1 7fig4 #i47 t x is compos$ ( two p>ts1 ! screw & ! nut4 ,! screw ,s is a cyl9d]1 ) a spiral protub]ance coil$ r\nd x1 call$ ! ?read2 ! nut ,n is p]=at$ to receive ! screw1 & ! inside ( ! nut has a spiral groove1 made to fit ! spiral ?read ( ! screw4 ,c>ol9e4 ,x is j l ?is little box1 ! lid ( :i* screws on ! box z y h describ$2 b :at is ?is h&le ,l :i* projects f ! nut8 ,mrs4 ,b4 ,x is a lev]1 :i* is atta*$ to ! nut1 )\t :i* ! screw is nev] us$ z a me*anical p[]4 ,! p[] ( ! screw1 complicat$ z x appe>s1 is ref]able to "o ( ! mo/ simple ( ! me*anical p[]s2 :i* ( !m d y ?9k x is8 ,c>ol9e4 ,9 appe>ance1 x mo/ resembles ! :eel & axle4 ,mrs4 ,b4 ,! lev]1 x is true1 has ! effect ( a :eel1 z x is ! means by :i* y turn ! nut1 or sometimes ! screw1 r\nd2 b ! lev] is n consid]$ z compos+ a "p ( ! screw1 ?\gh x is true1 t x is necess>ily atta*$ to x4 ,emily4 ,! spiral ?read ( ! screw resembles1 ,i ?9k1 an incl9$ plane3 x is a sort ( slope1 by means ( :i* ! nut asc5ds m easily ?an x w\ld d if rais$ p]p5dicul>ly2 & x s]ves to support x :5 at re/4 ,mrs4 ,b4 ,v well3 if y cut a slip ( pap] 9 ! =m ( an incl9$ plane1 & w9d x r\nd y\r p5cil1 :i* w repres5t ! cyl9d]1 y w f9d t x makes a spiral l9e1 correspond+ to ! spiral protub]ance ( ! screw4 7,fig4 #aj47 ,emily4 ,v true2 ! nut !n asc5ds an incl9$ plane1 b asc5ds x 9 a spiral1 in/ead ( a /raight l9e3 ! clos] ! ?reads ( ! screw1 ! m easy ! asc5t3 x is l hav+ %all[1 in/ead ( /eep /eps to asc5d4 ,mrs4 ,b4 ,yes2 except+ t ! nut takes no /eps1 z x gradually w9ds up or d[n2 !n obs]ve1 t ! clos] ! ?reads ( ! screw1 ! less is its asc5t 9 turn+ r\nd1 & ! great] is its p[]2 s t we return to ! old pr9ciple1--:at is sav$ 9 p[] is lo/ 9 "t4 ,emily4 ,_c ! p[] ( ! screw be increas$ also1 by l5g!n+ ! lev] atta*$ to ! nut8 ,mrs4 ,b4 ,c]ta9ly4 ,! screw1 ) ! addition ( ! lev]1 =ms a v p[]ful ma*9e1 employ$ ei!r = compression or to raise heavy weights4 ,x is us$ by book-b9d]s1 to press ! leaves ( books toge!r2 x is us$ also 9 cid] & w9e presses1 9 co9+1 & = a v>iety ( o!r purposes4 ,emily4 ,pray1 ,mrs4 ,b41 by :at rule d y e/imate ! p[] ( ! screw8 ,mrs4 ,b4 ,by measur+ ! circumf]5ce ( ! circle1 :i* ! end ( ! lev] w\ld =m 9 "o :ole revolution1 & comp>+ ?is ) ! di/ance f ! c5tre ( "o ?read ( ! screw1 to t ( its next contigu\s turn2 = :il/ ! lev] travels t :ole di/ance1 ! screw rises or falls only ?r\gh ! di/ance f "o coil to ano!r4 ,c>ol9e4 ,i ?9k t ,i h sometimes se5 ! lev] atta*$ to ! screw1 & n to ! nut1 z x is repres5t$ 9 ! figure4 ,mrs4 ,b4 ,?is is frequ5tly done1 b x does n 9 any degree affect ! p[] ( ! in/rum5t4 ,all ma*9es are compos$ ( "o or m ( ^! six me*anical p[]s we h exam9$2 ,i h b "o m rem>k to make to y relative to !m1 :i* is1 t friction 9 a consid]able degree dim9i%es _! =ce3 all[ance mu/ !re=e always be made = x1 9 ! con/ruction ( ma*9]y4 ,c>ol9e4 ,by friction1 d y mean "o "p ( ! ma*9e rubb+ aga9/ ano!r "p contigu\s to x8 ,mrs4 ,b4 ,yes2 friction is ! resi/ance :i* bodies meet ) 9 rubb+ aga9/ ea* o!r2 !re is no su* ?+ z p]fect smoo?ness or ev5ness 9 nature2 poli%$ metals1 ?\gh !y we> t appe>ance m ?an mo/ o!r bodies1 are f> f really possess+ x2 & _! inequalities may frequ5tly be p]ceiv$ ?r\gh a good magnify+ glass4 ,:51 !re=e1 ! surfaces ( ! two bodies come 9 contact1 ! prom95t p>ts ( ! "o1 w (t5 fall into ! holl[ p>ts ( ! o!r1 & occasion m or less resi/ance to motion4 ,c>ol9e4 ,b if a ma*9e is made ( poli%$ metal1 z a wat* = in/ance1 ! friction mu/ be v trifl+8 ,mrs4 ,b4 ,9 proportion z ! surfaces ( bodies are well poli%$1 ! friction is d\btless dim9i%$2 b x is always consid]able1 & x is usually comput$ to de/roy "o-?ird ( ! p[] ( a ma*9e4 ,oil or grease is us$ to less5 friction3 x acts z a poli%1 by fill+ up ! cavities ( ! rubb+ surfaces1 & ?us mak+ !m slide m easily ov] ea* o!r4 ,c>ol9e4 ,is x = ?is reason t :eels are greas$1 & ! locks & h+es ( doors oil$8 ,mrs4 ,b4 ,yes2 9 ^! in/ances ! contact ( ! rubb+ surfaces is s close1 & !y are s con/antly 9 use1 t !y require to be frequ5tly oil$1 or a consid]able degree ( friction is produc$4 ,!re are two k9ds ( friction2 ! fir/ is occasion$ by ! rubb+ ( ! surfaces ( bodies aga9/ ea* o!r1 ! second1 by ! roll+ ( a circul> body2 z t ( a c>riage :eel ^u ! gr\nd3 ! friction result+ f ! fir/ is mu* ! mo/ consid]able1 = great =ce is requir$ to enable ! slid+ body to ov]come ! resi/ance :i* ! asp]ities ( ! surfaces 9 contact oppose to its motion1 & x mu/ be ei!r lift$ ov]1 or break ?r\gh !m2 :il/1 9 ! second k9d ( friction1 ! r\gh p>ts roll ov] ea* o!r ) comp>ative facility2 h5ce x is1 t :eels are (t5 us$ = ! sole purpose ( dim9i%+ ! resi/ance f friction4 ,emily4 ,?is is "o ( ! advantages ( c>riage :eels1 is x n8 ,mrs4 ,b4 ,yes2 & ! l>g] ! circumf]5ce ( ! :eel ! m readily x c ov]come any consid]able ob/acles1 su* z /ones1 or inequalities 9 ! road4 ,:51 9 desc5d+ a /eep hill1 we fa/5 "o ( ! :eels1 we decrease ! velocity ( ! c>riage1 by increas+ ! friction4 ,c>ol9e4 ,t is to say1 by conv]t+ ! roll+ friction into ! rubb+ friction4 ,& :5 y _h ca/]s put to ! legs ( ! table1 9 ord] to move x m easily1 y *ang$ ! rubb+ into ! roll+ friction4 ,mrs4 ,b4 ,!re is ano!r circum/ance :i* we h already notic$1 z dim9i%+ ! motion ( bodies1 & :i* greatly affects ! p[] ( ma*9es4 ,?is is ! resi/ance ( ! m$ium1 9 :i* a ma*9e is work$4 ,all fluids1 :e!r ela/ic l air1 or non-ela/ic l wat] & o!r liquids1 are call$ m$iums2 & _! resi/ance is proportion$ to _! d5sity2 = ! m matt] a body conta9s1 ! great] ! resi/ance x w oppose to ! motion ( ano!r body /rik+ aga9/ x4 ,emily4 ,x w\ld !n be mu* m difficult to "w a ma*9e "u wat] ?an 9 ! air8 ,mrs4 ,b4 ,c]ta9ly1 if a ma*9e c\ld be work$ 9 vacuo1 & )\t friction1 x w\ld n be imp$$1 b ?is is unatta9able2 a consid]able r$uction ( p[] mu/ !re=e be all[$ =1 f friction & ! resi/ance ( ! m$ium4 ,we %all "h conclude our obs]vations on ! me*anical p[]s4 ,at our next meet+ ,i %all endeav\r to give y an explanation ( ! motion ( ! heav5ly bodies4 ,que/ions #ca4 7,pg4 #fb7 ,describe a pulley1 & its use4 #cb4 7,pg4 #fb7 ,:at is meant by a fix$ pulley & :y is n p[] ga9$ by its employm5t8 7fig4 #a4 plate #e47 #cc4 7,pg4 #fb7 ,( :at use is ! fix$ pulley8 #cd4 7,pg4 #fc7 ,h[ is ! p[] ga9$ by a moveable pulley1 expla9$ by means ( fig4 #b4 plate #e8 #ce4 7,pg4 #fc7 ,:at proportion mu/ ! p[] be> to ! weight 9 fig4 #b1 t _! mom5tums may be equal8 #cf4 7,pg4 #fd7 ,:at is a fundam5tal law z respects p[] & "t8 #cg4 7,pg4 #fd7 ,if to ga9 p[] we mu/ lose "t1 :at advantage d we d]ive f ! me*anical p[]s8 #ch4 7,pg4 #fd7 ,:at "n is giv5 to two or m pulleys connect$ by "o /r+8 #ci4 7,pg4 #fd7 ,h[ d we e/imate ! p[] ga9$ by a sy/em ( pulleys8 #dj4 7,pg4 #fe7 ,:at is repres5t$ by fig4 #e4 plate #e8 #da4 7,pg4 #fe7 ,h[ does ! :eel op]ate 9 increas+ p[]8 #db4 7,pg4 #fe7 ,h[ is ?is comp>$ ) ! lev]8 #dc4 7,pg4 #fe7 ,h[ does a h&le fix$ to an axle1 repres5t a :eel1 fig4 #f8 #dd4 7,pg4 #fe7 ,h[ c\ld we increase ! p[] 9 ?is in/rum5t8 #de4 7,pg4 #ff7 ,:at o!r =ces besides ! p[] ( m51 d we employ to move ma*9es8 #df4 7,pg4 #ff7 ,:at w s]ve z an example ( an incl9$ plane8 #dg4 7,pg4 #ff7 ,9 :at proportion does x ga9 p[]8 7fig4 #g47 #dh4 7,pg4 #ff7 ,to :at is ! w$ge comp>$8 7fig4 #h47 #di4 7,pg4 #ff7 ,h[ does its p[] increase8 #ej4 7,pg4 #fg7 ,:y is x r a comp\nd ?an a simple p[]8 #ea4 7,pg4 #fg7 ,:at common in/rum5ts act ^u ! pr9ciple ( ! incl9$ plane1 or ! w$ge8 #eb4 7,pg4 #fg7 ,:y does a knife cut be/ :5 drawn across8 #ec4 7,pg4 #fg7 ,! screw has two ess5tial p>ts2 :at are !y8 #ed4 7,pg4 #fg7 ,:at o!r in/rum5t is us$ to turn ! screw8 #ee4 7,pg4 #fg7 ,h[ c y comp>e ! screw ) an incl9$ plane8 ,fig4 #aj4 #ef4 7,pg4 #fh7 ,by :at two means may ! p[] ( ! screw be increas$8 #eg4 7,pg4 #fh7 ,h[ d we e/imate ! p[] ga9$ by ! screw8 #eh4 7,pg4 #fh7 ,is ! lev] always atta*$ to ! nut1 z 9 ! figure8 #ei4 7,pg4 #fh7 ,:at is said respect+ ! composition ( all ma*9es1 & = :at mu/ all[ance always be made 9 e/imat+ _! p[]8 #fj4 7,pg4 #fi7 ,:at is meant by friction1 & :at causes x8 #fa4 7,pg4 #fi7 ,h[ may friction be dim9i%$8 #fb4 7,pg4 #fi7 ,friction is ( two k9ds1 :at are !y8 #fc4 7,pg4 #fi7 ,= :at purpose are :eels (t5 us$8 #fd4 7,pg4 #fi7 ,:5 is ! friction ( a c>riage :eel *ang$ f ! roll+ to ! rubb+ friction8 #fe4 7,pg4 #gj7 ,:at is a m$ium1 & 9 :at proportion does x dim9i% motion8 #ff4 7,pg4 #gj7 ,"u :at circum/ances mu/ a body be plac$1 9 ord] to move )\t imp$im5t8 ,,conv]sation ,,vi4 ,,causes ,,( ,,! ,,motion ,,( ,,! ,,heav5ly ,,bodies4 ,,( ,,! ,,e>?',s ,,annual ,,motion4 ,,( ,,! ,,planets ,,& ,,_! ,,motion4 ,,( ,,! ,,diurnal ,,motion ,,( ,,! ,,e>? ,,& ,,planets4 ,,c>ol9e4 ,i am come to y to-day q elat$ ) ! _s ( opposition1 ,mrs4 ,b42 = ,i h discov]$ su* a p[]ful objection to y\r !ory ( attraction1 t ,i d\bt :e!r ev5 y\r conjuror ,newton1 ) 8 magic w& ( gravitation1 w be able to dispel x4 ,mrs4 ,b4 ,well1 my de>1 pray :at is ?is weighty objection8 ,illu/ration3 ,,plate ,,vi4 ,c>ol9e4 ,y say t ! e>? revolves 9 its orbit r\nd ! sun once 9 a ye>1 & t bodies attract 9 proportion to ! quantity ( matt] !y conta92 n[ we all "k ! sun to be mu* l>g] ?an ! e>?3 :y1 !re=e does x n draw ! e>? into itself2 y w n1 ,i suppose1 pret5d to say t we are fall+ t[>ds ! sun8 ,emily4 ,h[ev] plausible y\r objection appe>s1 ,c>ol9e1 ,i ?9k y place too mu* reliance ^u x3 :5 any "o has giv5 su* conv9c+ pro(s ( sagacity & wisdom z ,sir ,isaac ,newton1 :5 we f9d t 8 op9ions are univ]sally receiv$ & adopt$1 is x to be expect$ t any objection we c advance %\ld ov]turn !m8 ,c>ol9e4 ,yet ,i confess t ,i am n incl9$ to yield implicit fai? ev5 to op9ions ( ! great ,newton3 = :at purpose are we end[$ ) reason1 if we are d5i$ ! privilege ( mak+ use ( x1 by judg+ = ourselves4 ,mrs4 ,b4 ,x is reason itself :i* tea*es u1 t :5 we1 novices 9 sci5ce1 />t objections to !ories e/abli%$ by m5 ( k & wisdom1 we %\ld be diffid5t r ( our own ?an ( _! op9ion4 ,i am f> f wi%+ to lay ! lea/ re/ra9t on y\r que/ions2 y _c be bett] conv9c$ ( ! tru? ( a sy/em1 ?an by f9d+ t x resi/s all y\r attacks1 b ,i w\ld advise y n to advance y\r objections ) s mu* confid5ce1 9 ord] t ! discov]y ( _! fallacy may be att5d$ ) less mortification4 ,9 answ] to t y h j propos$1 ,i c only say1 t ! e>? really is attract$ by ! sun4 ,c>ol9e4 ,take c>e1 at lea/1 t we are n consum$ by him1 ,mrs4 ,b4 ,mrs4 ,b4 ,we are 9 no dang]2 b ,newton1 our magician1 z y are pleas$ to call him1 _c extricate himself f ?is difficulty )\t ! aid ( "s cabali/ical figures1 :i* ,i mu/ draw = him4 ,let u suppose ! e>?1 at its creation1 to h be5 project$ =w>ds into univ]sal space3 we "k t if no ob/acle imp$$ its c\rse x w\ld proce$ 9 ! same direction1 & ) a uni=m velocity = ev]4 ,9 fig4 #a4 plate #f1 ,a repres5ts ! e>?1 & ,s ! sun4 ,we %all suppose ! e>? to be arriv$ at ! po9t 9 :i* x is repres5t$ 9 ! figure1 hav+ a velocity :i* w\ld c>ry x on to ,b 9 ! space ( "o mon?2 :il/ ! sun's attraction w\ld br+ x to ,c 9 ! same space ( "t4 ,obs]ve t ! two =ces ( projection & attraction d n act 9 opposition1 b p]p5dicul>ly1 or at a "r angle to ea* o!r4 ,c y tell me n[1 h[ ! e>? w move8 ,emily4 ,i recollect y\r tea*+ u t a body act$ ^u by two =ces p]p5dicul> to ea* o!r1 w\ld move 9 ! diagonal ( a p>allelogram2 if1 !re=e1 ,i complete ! p>allelogram1 by draw+ ! l9es ,c ,d1 ,b ,d1 ! e>? w move 9 ! diagonal ,a ,d4 ,mrs4 ,b4 ,a ball /ruck by two =ces act+ p]p5dicul>ly to ea* o!r1 x is true1 moves 9 ! diagonal ( a p>allelogram2 b y mu/ obs]ve t ! =ce ( attraction is cont9ually act+ ^u our t]re/rial ball1 & produc+ an incessant deviation f its c\rse 9 a "r l9e1 :i* conv]ts x into t ( a curve-l9e2 e po9t ( :i* may be consid]$ z con/itut+ ! diagonal ( an inf9itely small p>allelogram4 ,let u reta9 ! e>? a mom5t at ! po9t ,d1 & consid] h[ x w be affect$ by ! comb9$ action ( ! two =ces 9 its new situation4 ,x /ill reta9s its t5d5cy to fly (f 9 a /raight l9e2 b a /raight l9e w\ld n[ c>ry x away to ,f1 :il/ ! sun w\ld attract x 9 ! direction ,d ,s2 h[ !n w x proce$8 ,emily4 ,x w g on 9 a curve-l9e1 9 a direction betwe5 t ( ! two =ces4 ,mrs4 ,b4 ,9 ord] to "k exactly :at c\rse ! e>? w foll[1 draw ano!r p>allelogram simil> to ! fir/1 9 :i* ! l9e ,d ,f describes ! =ce ( projection1 & ! l9e ,d ,s t ( attraction2 & y w f9d t ! e>? w proce$ 9 ! curve-l9e ,d ,g4 ,c>ol9e4 ,y mu/ n[ all[ me to draw a p>allelogram1 ,mrs4 ,b4 ,let me consid] 9 :at direction w ! =ce ( projection n[ impel ! e>?4 ,mrs4 ,b4 ,fir/ draw a l9e f ! e>? to ! sun repres5t+ ! =ce ( attraction2 !n describe ! =ce ( projection at a "r angle to x4 ,c>ol9e4 ,! e>? w !n move 9 ! curve ,g ,i1 ( ! p>allelogram ,g ,h ,i ,k4 ,mrs4 ,b4 ,y recollect t a body act$ ^u by two =ces1 moves ?r\gh a diagonal1 9 ! same "t t x w\ld h mov$ ?r\gh "o ( ! sides ( ! p>allelogram1 7 x act$ ^u by "o =ce only4 ,! e>? has pass$ ?r\gh ! diagonals ( ^! ?ree p>allelograms1 9 ! space ( ?ree mon?s1 & has p]=m$ "o qu>t] ( a circle2 & on ! same pr9ciple x w g on till x has complet$ ! :ole ( ! circle4 ,x w !n recomm5ce a c\rse1 :i* x has pursu$ ev] s9ce x fir/ issu$ f ! h& ( its ,creator1 & :i* !re is e reason to suppose x w cont9ue to foll[1 z long z x rema9s 9 exi/5ce4 ,emily4 ,:at a gr& & beautiful effect result+ f s simple a cause6 ,c>ol9e4 ,x af=ds an example1 on a magnific5t scale1 ( ! curvil9e> motion1 :i* y taught u 9 me*anics4 ,! attraction ( ! sun is ! c5tripetal =ce1 :i* conf9es ! e>? to a c5tre2 & ! impulse ( projection1 ! c5trifugal =ce1 :i* impels ! e>? to quit ! sun1 & fly (f 9 a tang5t4 ,mrs4 ,b4 ,exactly s4 ,a simple mode ( illu/rat+ ! effect ( ^! comb9$ =ces on ! e>?1 is to cut a slip ( c>d 9 ! =m ( a c>p5t]'s squ>e1 z ,a1 ,b1 ,c2 7fig4 #b4 plate #f47 ! po9t ,b w be a "r angle1 ! sides ( ! squ>e be+ p]p5dicul> to ea* o!r2 aft] hav+ done ?is y are to describe a small circle at ! angul> po9t ,b1 repres5t+ ! e>?1 & to fa/5 ! extremity ( "o ( ! legs ( ! squ>e to a fix$ po9t ,a1 :i* we %all consid] z ! sun4 ,?us situat$1 ! two sides ( ! squ>e w repres5t bo? ! c5trifugal & c5tripetal =ces2 ,a ,b1 repres5t+ ! c5tripetal1 & ,b ,c1 ! c5trifugal =ce2 if y n[ draw x r\nd ! fix$ po9t1 y w see h[ ! direction ( ! c5trifugal =ce v>ies1 con/antly =m+ a tang5t to ! circle 9 :i* ! e>? moves1 z x is con/antly at a "r angle ) ! c5tripetal =ce4 ,emily4 ,! e>? !n1 gravitates t[>ds ! sun1 )\t ! slighte/ dang] ei!r ( approa*+ ne>]1 or rec$+ fur!r f x4 ,h[ admirably ?is is contriv$6 ,if ! two =ces :i* produce ?is curv$ motion1 _h n be5 s accurately adju/$1 "o w\ld ultimately h prevail$ ov] ! o!r1 & we %\ld ei!r h approa*$ s ne> ! sun z to h be5 burnt1 or h rec$$ s f> f x z to h be5 froz54 ,mrs4 ,b4 ,:at w y say1 my de>1 :5 ,i tell y1 t ^! two =ces are n1 9 fact1 s proportion$ z to produce circul> motion 9 ! e>?8 ,we actually revolve r\nd ! sun 9 an elliptical or oval orbit1 ! sun be+ situat$ 9 "o ( ! foci or c5tres ( ! oval1 s t ! sun is at "s p]iods mu* ne>] to ! e>?1 ?an at o!rs4 ,c>ol9e4 ,y mu/ expla9 to u1 at lea/1 9 :at mann] we avoid ! ?reat5$ de/ruction4 ,mrs4 ,b4 ,let u suppose t :5 ! e>? is at ,a1 7fig4 #c47 its projectile =ce %\ld n h giv5 x a velocity suffici5t to c\nt]balance t ( gravity1 s z to enable ^! p[]s conjo9tly to c>ry x r\nd ! sun 9 a circle2 ! e>?1 in/ead ( describ+ ! l9e ,a ,c1 z 9 ! =m] figure1 w approa* ne>] ! sun 9 ! l9e ,a ,b4 ,c>ol9e4 ,"u ^! circum/ances1 ,i see n :at is to prev5t our approa*+ ne>] & ne>] ! sun1 till we fall into x3 = its attraction increases z we advance t[>ds x1 & produces an accel]at$ velocity 9 ! e>?1 :i* increases ! dang]4 ,mrs4 ,b4 ,!re is ano!r seem+ dang]1 ( :i* y are n aw>e4 ,obs]ve1 t z ! e>? approa*es ! sun1 ! direction ( its projectile =ce is no long] p]p5dicul> to t ( its attraction1 b incl9es m ne>ly to x4 ,:5 ! e>? rea*es t "p ( its orbit at ,b1 ! =ce ( projection w\ld c>ry x to ,d1 :i* br+s x ne>] ! sun in/ead ( be>+ x away f x4 ,emily4 ,if1 !n1 we are driv5 by "o p[]1 & drawn by ! o!r to ?is c5tre ( de/ruction1 h[ is x possible = u to escape8 ,mrs4 ,b4 ,a little pati5ce1 & y w f9d t we are n )\t res\rce4 ,! e>? cont9ues approa*+ ! sun ) a uni=mly increas+ accel]at$ motion1 till x rea*es ! po9t ,e2 9 :at direction w ! projectile =ce n[ impel x8 ,emily4 ,9 ! direction ,e ,f4 ,"h !n ! two =ces act p]p5dicul>ly to ea* o!r1 ! l9es repres5t+ !m =m+ a "r angle1 & ! e>? is situat$ j z x 0 9 ! prec$+ figure2 !re=e1 f ?is po9t1 x %\ld revolve r\nd ! sun 9 a circle4 ,mrs4 ,b4 ,no1 all ! circum/ances d n agree4 ,9 motion r\nd a c5tre1 y recollect t ! c5trifugal =ce increases ) ! velocity ( ! body1 or 9 o!r words1 ! quick] x moves ! /rong] is its t5d5cy to fly (f 9 a "r l9e4 ,:5 ! e>?1 !re=e1 arrives at ,e1 its accel]at$ motion w h s f> increas$ its velocity1 & consequ5tly its c5trifugal =ce1 t ! latt] w prevail ov] ! =ce ( attraction1 & =ce ! e>? away f ! sun till x rea*es ,g4 ,c>ol9e4 ,x is ?us !n t we escape f ! dang]\s vic9ity ( ! sun2 & 9 proportion z we rec$e f x1 ! =ce ( its attraction1 &1 consequ5tly1 ! velocity ( ! e>?'s motion1 are dim9i%$4 ,mrs4 ,b4 ,yes4 ,f ,g ! direction ( projection is t[>ds ,h1 t ( attraction t[>ds ,s1 & ! e>? proce$s betwe5 !m ) a uni=mly ret>d$ motion1 till x has complet$ its revolution4 ,?us y see t ! e>? travels r\nd ! sun1 n 9 a circle1 b an ellipsis1 ( :i* ! sun occupies "o ( ! foci2 & t 9 its c\rse1 ! e>? alt]nately approa*es & rec$es f x1 )\t any dang] ( be+ ei!r swall[$ up1 or be+ entirely c>ri$ away f x4 ,c>ol9e4 ,& ,i obs]ve1 t :at ,i appreh5d$ to be a dang]\s irregul>ity1 is ! means by :i* ! mo/ p]fect ord] & h>mony are produc$4 ,emily4 ,! e>? travels !n at a v unequal rate1 its velocity be+ accel]at$ z x approa*es ! sun1 & ret>d$ z x rec$es f x4 ,mrs4 ,b4 ,x is ma!matically demon/rable1 t1 9 mov+ r\nd a po9t t[>ds :i* x is attract$1 a body passes ov] equal areas1 9 equal times4 ,! :ole ( ! space conta9$ )9 ! e>?'s orbit1 is 9 fig4 #d1 divid$ into a numb] ( areas or surfaces2 #a1 #b1 #c1 #d1 c4 all ( :i* are ( equal dim5sions1 ?\gh ( v diff]5t =ms2 "s ( !m1 y see1 are long & n>r[1 o!rs broad & %ort3 b !y ea* ( !m conta9 an equal quantity ( space4 ,an imag9>y l9e drawn f ! c5tre ( ! e>? to t ( ! sun1 & keep+ pace ) ! e>? 9 its revolution1 passes ov] equal areas 9 equal times2 t is to say1 if x is a mon? go+ f ,a to ,b1 x w be a mon? go+ f ,b to ,c1 & ano!r f ,c to ,e1 & s on2 & ! areas ,a ,b ,s1 ,b ,c ,s1 ,c ,e ,s1 w be equal to ea* o!r1 al?\gh ! l9es ,a ,b1 ,b ,c1 ,c ,e1 are unequal4 ,c>ol9e4 ,:at long j\rneys ! e>? has to p]=m 9 ! c\rse ( a mon?1 9 "o "p ( h] orbit1 & h[ %ort !y are 9 ! o!r "p6 ,mrs4 ,b4 ,! inequality is n s consid]able z appe>s 9 ?is figure2 = ! e>?'s orbit is n s ecc5tric z x is !re describ$2 & 9 reality1 diff]s b little f a circle3 t "p ( ! e>?'s orbit ne>e/ ! sun is call$ its p]ihelion1 t "p mo/ di/ant f ! sun1 its aphelion2 & ! e>? is above ?ree millions ( miles ne>] ! sun at its p]ihelion ?an at its aphelion4 ,emily4 ,i ?9k ,i c trace a consequ5ce f ^! diff]5t situations ( ! e>?2 are n !y ! cause ( summ] & w9t]8 ,mrs4 ,b4 ,on ! contr>y1 dur+ ! height ( summ]1 ! e>? is 9 t "p ( its orbit :i* is mo/ di/ant f ! sun1 & x is dur+ ! sev]ity ( w9t]1 t x approa*es ne>e/ to x4 ,emily4 ,t is v extraord9>y2 & h[ !n d y acc\nt = ! heat be+ greate/1 :5 we are mo/ di/ant f ! sun8 ,mrs4 ,b4 ,! diff]5ce ( ! e>?'s di/ance f ! sun 9 summ] & w9t]1 :5 comp>$ ) its total di/ance f ! sun1 is b inconsid]able4 ,! e>?1 x is true1 is above ?ree millions ( miles ne>] ! sun 9 w9t] ?an 9 summ]2 b t di/ance1 h[ev] great x at fir/ appe>s1 s9ks into insignificance 9 comp>ison ) #ie millions ( miles1 :i* is our mean di/ance f ! sun4 ,! *ange ( temp]ature1 aris+ f ?is diff]5ce1 w\ld sc>cely be s5sible1 ev5 7 x n completely ov]p[]$ by o!r causes :i* produce ! v>iations ( ! seasons2 b ^! ,i %all def] expla9+1 till we h made "s fur!r obs]vations on ! heav5ly bodies4 ,c>ol9e4 ,& %\ld n ! sun appe> small] 9 summ]1 :5 x is s mu* fur!r f u8 ,mrs4 ,b4 ,x actually does1 :5 accurately measur$2 b ! app>5t diff]5ce 9 size1 is1 ,i believe1 n p]ceptible to ! nak$ eye4 ,emily4 ,!n1 s9ce ! e>? moves ) ! greate/ velocity 9 t "p ( its orbit 9 :i* x is ne>e/ ! sun1 x mu/ h complet$ its j\rney ?r\gh t half ( its orbit1 9 a %ort] "t ?an ?r\gh ! o!r8 ,mrs4 ,b4 ,yes1 x is ab\t sev5 days long] p]=m+ ! summ]-half ( its orbit1 ?an ! w9t]-half2 & ! summ]s are consequ5tly sev5 days long] 9 ! nor!rn1 ?an !y are 9 ! s\!rn hemisph]e4 ,! revolution ( all ! planets r\nd ! sun1 is ! result ( ! same causes1 & is p]=m$ 9 ! same mann]1 z t ( ! e>?4 ,c>ol9e4 ,pray :at are ! planets8 ,mrs4 ,b4 ,!y are ^? cele/ial bodies1 :i* revolve l our e>?1 ab\t ! sun2 !y are suppos$ to resemble ! e>? also 9 _m o!r respects2 & we are l$ by analogy1 to suppose !m to be inhabit$ worlds4 ,c>ol9e4 ,i h he>d s1 b d y n ?9k su* an op9ion too great a /ret* ( ! imag9ation8 ,mrs4 ,b4 ,"s ( ! planets are prov$ to be l>g] ?an ! e>?2 x is only _! imm5se di/ance f u1 :i* r5d]s _! app>5t dim5sions s small4 ,n[1 if we consid] !m z enorm\s globes1 in/ead ( small tw9kl+ spots1 we %all be l$ to suppose t ! ,almighty w\ld n h creat$ !m m]ely = ! purpose ( giv+ u a little light 9 ! night1 z x 0 =m]ly imag9$2 & we %\ld f9d x m consi/5t ) our ideas ( ! ,div9e wisdom & b5efic5ce1 to suppose t ^! cele/ial bodies %\ld be creat$ = ! habitation ( be+s1 :o are1 l u1 bless$ by 8 provid5ce4 ,bo? 9 a moral1 z well z a physical po9t ( view1 x appe>s to me m rational to consid] ! planets z worlds revolv+ r\nd ! sun2 & ! fix$ />s z o!r suns1 ea* ( !m att5d$ by _! respective sy/em ( planets1 to :i* !y imp>t _! influ5ce4 ,we h br\ght our telescopes to su* a degree ( p]fection1 t f ! appe>ances :i* ! moon exhibits :5 se5 ?r\gh !m1 we h v good reason to conclude t x is a habitable globe3 = ?\gh x is true t we _c disc]n its t[ns & p1 we c pla9ly p]ceive its m\nta9s & valleys3 & "s a/ronom]s h gone s f> z to imag9e t !y discov]$ volcanos4 ,emily4 ,if ! fix$ />s are suns1 ) planets revolv+ r\nd !m1 :y %\ld we n see ^? planets z well z _! suns8 ,mrs4 ,b4 ,9 ! fir/ place1 we conclude t ! planets ( o!r sy/ems 7l ^? ( our own7 are mu* small] ?an ! suns :i* give !m light2 !re=e at a di/ance s great z to make ! suns appe> l fix$ />s1 ! planets w\ld be q invisible4 ,secondly1 ! light ( ! planets be+ only reflect$ light1 is mu* m feeble ?an t ( ! fix$ />s4 ,!re is exactly ! same diff]5ce z betwe5 ! light ( ! sun & t ( ! moon2 ! fir/ be+ a fix$ />1 ! second a planet4 ,emily4 ,b ! planets appe> to u z bright z ! fix$ />s1 & ^! y tell u are suns l our own2 :y !n d we n see !m by daylight1 :5 !y mu/ be j z lum9\s z !y are 9 ! night8 ,mrs4 ,b4 ,bo? are invisible f ! same cause3 _! light is s fa9t1 comp>$ to t ( ! sun1 t x is entirely effac$ by x3 ! light emitt$ by ! fix$ />s may probably be z great z t ( our sun1 at an equal di/ance2 b !y be+ s mu* m remote1 x is diffus$ ov] a great] space1 & is 9 consequ5ce proportionally less5$4 ,c>ol9e4 ,true2 ,i c see mu* bett] by ! light ( a c&le t is ne> me1 ?an by t ( "o at a great di/ance4 ,b ,i d n und]/& :at makes ! planets %9e8 ,mrs4 ,b4 ,:at is t :i* makes ! gilt buttons on y\r bro!rs coat %9e8 ,c>ol9e4 ,! sun4 ,b if x 0 ! sun :i* made ! planets %9e1 we %\ld see !m 9 ! day-"t1 :5 ! sun %one ^u !m2 or if ! fa9tness ( _! light prev5t$ our see+ !m 9 ! day1 we %\ld n see !m at all1 = ! sun _c %9e ^u !m 9 ! night4 ,mrs4 ,b4 ,!re y are 9 error4 ,b 9 ord] to expla9 ?is to y1 ,i mu/ fir/ make y acqua9t$ ) ! v>i\s motions ( ! planets4 ,y "k1 t accord+ to ! laws ( attraction1 ! planets belong+ to our sy/em all gravitate t[>ds ! sun2 & t ?is =ce1 comb9$ ) t ( projection1 w occasion _! revolution r\nd ! sun1 9 orbits m or less elliptical1 accord+ to ! proportion :i* ^! two =ces be> to ea* o!r4 ,b ! planets h also ano!r motion3 !y revolve ^u _! axis4 ,! axis ( a planet is an imag9>y l9e :i* passes ?r\gh its c5tre1 & on :i* x turns2 & x is ?is motion :i* produces day & night4 ,x is day on t side ( ! planet :i* faces ! sun2 & on ! opposite side1 :i* rema9s 9 d>kness1 x is night4 ,our e>?1 :i* we consid] z a planet1 is #bd h\rs 9 p]=m+ "o revolution on its axis2 9 t p]iod ( "t1 !re=e1 we h a day & a night2 h5ce ?is revolution is call$ ! e>?'s diurnal or daily motion2 & x is ?is revolution ( ! e>? f we/ to ea/ :i* produces an app>5t motion ( ! sun1 moon & />s1 9 a contr>y direction4 ,let u n[ suppose ourselves to be be+s indep5d5t ( any planet1 travell+ 9 ! skies1 & look+ ^u ! e>? f a po9t z di/ant f x z f o!r planets4 ,c>ol9e4 ,x w\ld n be flatt]+ to u1 its inhabitants1 to see x make s insignificant an appe>ance4 ,mrs4 ,b4 ,to ^? accu/om$ to contemplate x 9 ?is light1 x c\ld nev] appe> m glori\s4 ,we are taught by sci5ce to di/ru/ appe>ances2 & in/ead ( consid]+ ! fix$ />s & planets z little po9ts1 we look ^u !m ei!r z brilliant suns1 or habitable worlds2 & we consid] ! :ole toge!r z =m+ "o va/ & magnific5t sy/em1 wor?y ( ! ,div9e h& by :i* x 0 creat$4 ,emily4 ,i c sc>cely conceive ! idea ( ?is imm5sity ( creation2 x seems too sublime = our imag9ation2--& to ?9k t ! goodness ( ,provid5ce ext5ds ov] millions ( worlds ?r\gh\t a b\ndless univ]se--,ah6 ,mrs4 ,b41 x is we only :o become trifl+ & insignificant be+s 9 s magnific5t a creation6 ,mrs4 ,b4 ,?is idea %\ld tea* u humility1 b )\t produc+ despond5cy4 ,! same ,almighty h& :i* guides ^! c\ntless worlds 9 _! undeviat+ c\rse1 conducts ) equal p]fection1 ! blood z x circulates ?r\gh ! ve9s ( a fly1 & op5s ! eye ( ! insect to behold ,8 wond]s4 ,not)/&+ ?is imm5se scale ( creation1 !re=e1 we ne$ n fe> t we %all be disreg>d$ or =gott54 ,b to return to our /ation 9 ! skies4 ,we 71 if y recollect1 view+ ! e>? at a great di/ance1 9 appe>ance a little />1 "o side illum9$ by ! sun1 ! o!r 9 obscurity4 ,b w\ld y believe x1 ,c>ol9e1 _m ( ! inhabitants ( ?is little /> imag9e t :5 t "p :i* !y inhabit is turn$ f ! sun1 d>kness prevails ?r\gh\t ! univ]se1 m]ely because x is night ) !m2 :il/1 9 reality1 ! sun nev] ceases to %9e ^u e planet4 ,:51 !re=e1 ^! little ignorant be+s look ar\nd !m dur+ _! night1 & behold all ! />s %9+1 !y _c imag9e :y ! planets1 :i* are d>k bodies1 %\ld %9e2 conclud+1 t s9ce ! sun does n illum9e !mselves1 ! :ole univ]se mu/ be 9 d>kness4 ,c>ol9e4 ,i confess t ,i 0 "o ( ^! ignorant p2 b ,i am n[ v s5sible ( ! absurdity ( su* an idea4 ,to ! inhabitants ( ! o!r planets1 !n1 we mu/ appe> z a little />8 ,mrs4 ,b4 ,yes1 to ^? :i* revolve r\nd our sun2 = s9ce ^? :i* may belong to o!r sy/ems1 7& ^: exi/5ce is only hypo!tical7 are invisible to u1 x is probable t we also are invisible to !m4 ,emily4 ,b !y may see our sun z we d !irs1 9 appe>ance a fix$ />8 ,mrs4 ,b4 ,no d\bt2 if ! be+s :o inhabit ^? planets are end[$ ) s5ses simil> to ours4 ,by ! same rule we mu/ appe> z a moon to ! inhabitants ( our moon2 b on a l>g] scale1 z ! surface ( ! e>? is ab\t ?irte5 times z l>ge z t ( ! moon4 ,emily4 ,! moon1 ,mrs4 ,b41 appe>s to move 9 a diff]5t direction1 & 9 a diff]5t mann] f ! />s8 ,mrs4 ,b4 ,i %all def] ! explanation ( ! motion ( ! moon till our next int]view1 z x w\ld prolong our pres5t lesson too mu*4 ,que/ions #a4 7,pg4 #ga7 ,:at revolution does ! e>? p]=m 9 a ye>8 #b4 7,pg4 #ga7 ,_h ! e>? receiv$ a projectile =ce only1 at ! "t ( its creation1 h[ w\ld x h mov$8 #c4 7,pg4 #gb7 ,:at d ! l9es ,a ,b1 & ,a ,c1 repres5t 9 fig4 #a4 plate #f8 #d4 7,pg4 #gb7 ,:at h y be5 taught respect+ a body act$ ^u by two =ces at "r angles ) ea* o!r8 #e4 7,pg4 #gb7 ,h[ does ! =ce ( gravity *ange ! diagonal into a curv$ l9e8 #f4 7,pg4 #gb7 ,describe ! op]ation ( ! =ces ( projection & ( gravity z illu/rat$ by ! p>allelograms 9 ! figure8 #g4 7,pg4 #gb7 ,:at is ! law respect+ ! "t requir$ = motion 9 ! diagonal8 #h4 7,pg4 #gc7 ,:at portion ( a ye> is repres5t$ by ! ?ree diagonals 9 ! figure8 #i4 7,pg4 #gc7 ,h[ w :at y h le>n$ respect+ motion 9 a curve1 apply to ! e>?'s motion8 #aj4 7,pg4 #gc7 ,9 :at =m are y direct$ to cut a piece ( c>d to aid 9 illu/rat+ ! two =ces act+ ^u ! e>?8 #aa4 7,pg4 #gc7 ,h[ mu/ y apply x to ?is purpose8 7fig4 #b4 plate #f47 #ab4 7,pg4 #gc7 ,if ^! two =ces did n exactly balance ea* o!r1 :at w\ld result8 #ac4 7,pg4 #gc7 ,does ! e>? revolve 9 a circul> orbit8 #ad4 7,pg4 #gc7 ,:at results f its motion 9 an ellipsis8 #ae4 7,pg4 #gd7 ,:at is repres5t$ by ! l9es ,a ,c1 ,a ,b1 9 fig4 #c4 plate #f8 #af4 7,pg4 #gd7 ,7 ! projectile =ce to c>ry ! e>? f ,b to ,d1 7fig4 #c47 :at w\ld result8 #ag4 7,pg4 #gd7 ,:5 x has arriv$ at ,e1 :at angle w be =m$ by ! l9es repres5t+ ! two =ces8 #ah4 7,pg4 #gd7 ,:at effect w ! accel]at$ motion !n produce8 #ai4 7,pg4 #ge7 ,:at is ! =m ( ! e>?'s orbit1 & :at circum/ances produce ?is =m8 #bj4 7,pg4 #ge7 ,:at is ! consequ5ce z reg>ds ! regul>ity ( ! e>?'s motion8 #ba4 7,pg4 #ge7 ,:at law gov]ns z reg>ds ! spaces pass$ ov]1 & h[ is ?is expla9$ by fig4 #d4 plate #f8 #bb4 7,pg4 #ge7 ,:at is meant by p]ihelion1 & by aphelion8 #bc4 7,pg4 #ge7 ,:at is ! diff]5ce ( ! di/ance ( ! e>? f ! sun1 9 ^! two po9ts8 #bd4 7,pg4 #gf7 ,at :at season ( ! ye> is x ne>e/ to1 & at :at fur!/ f ! sun8 #be4 7,pg4 #gf7 ,:at is ! mean di/ance ( ! e>? f ! sun8 #bf4 7,pg4 #gf7 ,:y is b little effect produc$1 z reg>ds temp]ature1 by ! *ange ( di/ance8 #bg4 7,pg4 #gf7 ,has x any influ5ce on ! sun's app>5t size8 #bh4 7,pg4 #gf7 ,are ! summ] & w9t]1 half ye>s1 ( ! same l5g?2 :at is _! diff]5ce1 & :at is ! cause8 #bi4 7,pg4 #gf7 ,:at are ! planets8 #cj4 7,pg4 #gg7 ,:at circum/ances r5d] x probable t !y are habitable globes8 #ca4 7,pg4 #gg7 ,:at is believ$ respect+ ! fix$ />s8 #cb4 7,pg4 #gg7 ,:at discov]ies h be5 made 9 ! moon8 #cc4 7,pg4 #gg7 ,:at prev5ts our see+ ! planets1 if !re are any1 :i* revolve r\nd ! fix$ />s8 #cd4 7,pg4 #gg7 ,:at prev5ts our see+ ! />s & planets 9 ! day-"t8 #ce4 7,pg4 #gh7 ,:at o!r motions h ! e>? & planets1 besides t 9 _! orbits8 #cf4 7,pg4 #gh7 ,:at is ! imag9>y l9e call$1 r\nd :i* !y revolve8 #cg4 7,pg4 #gh7 ,h[ does ?is occasion night & day8 #ch4 7,pg4 #gh7 ,9 :at direction does ! e>? turn ^u its axis1 & :at app>5t motion ( ! sun1 moon1 & />s is !reby produc$8 #ci4 7,pg4 #gi7 ,:at mu/ be ! appe>ance ( ! e>? to an inhabitant ( "o ( ! planets8 #dj4 7,pg4 #gi7 ,:at ! appe>ance ( ! sun to ! inhabitants ( planets 9 o!r sy/ems8 #da4 7,pg4 #gi7 ,:at ! appe>ance ( ! e>? to an inhabitant ( ! moon8 ,,conv]sation ,,vii4 ,,( ,,! ,,planets4 ,,( ,,! ,,satellites ,,or ,,moons4 ,,gravity ,,dim9i%es ,,z ,,! ,,squ>e ,,( ,,! ,,di/ance4 ,,( ,,! ,,sol> ,,sy/em4 ,,( ,,comets4 ,,con/ellations1 ,,signs ,,( ,,! ,,zodiac4 ,,( ,,cop]nicus1 ,,newton1 c4 ,,mrs4 ,b4 ,! planets are di/+ui%$ into prim>y & second>y4 ,^? :i* revolve imm$iately ab\t ! sun are call$ prim>y4 ,_m ( ^! are att5d$ 9 _! c\rse by small] planets1 :i*1 revolve r\nd !m3 ^! are call$ second>y planets1 satellites1 or moons4 ,su* is our moon :i* accompanies ! e>?1 & is c>ri$ ) x r\nd ! sun4 ,emily4 ,h[ !n c y reconcile ! motion ( ! second>y planets to ! laws ( gravitation2 = ! sun is mu* l>g] ?an any ( ! prim>y planets2 & is n ! p[] ( gravity proportional to ! quantity ( matt]8 ,c>ol9e4 ,p]haps ! sun1 ?\gh mu* l>g]1 may be less d5se ?an ! planets4 ,fire y "k1 is v light1 & x may conta9 b little matt]1 ?\gh ( great magnitude4 ,mrs4 ,b4 ,we d n "k ( :at k9d ( matt] ! sun is made2 b we may be c]ta91 t s9ce x is ! g5]al c5tre ( attraction ( our sy/em ( planets1 x mu/ be ! body :i* conta9s ! greate/ quantity ( matt] 9 t sy/em4 ,y mu/ recollect1 t ! =ce ( attraction is n only proportional to ! quantity ( matt]1 b to ! degree ( proximity ( ! attractive body3 ?is p[] is weak5$ by be+ diffus$1 & dim9i%es z ! di/ance increases4 ,emily4 ,!n if a planet 0 to lose "o-half ( its quantity ( matt]1 x w\ld lose "o half ( its attractive p[]2 & ! same effect w\ld be produc$ by remov+ x to twice its =m] di/ance f ! sun2 t ,i und]/&4 ,mrs4 ,b4 ,n s p]fectly z y imag9e4 ,y are correct z respects ! dim9ution 9 size1 because ! attractive =ce is 9 ! same proportion z ! quantity ( matt]2 b 7 y to remove a planet to d\ble its =m] di/ance1 x w\ld reta9 b "o-f\r? "p ( its gravitat+ =ce2 = attraction decreases n 9 proportion to ! simple increase ( ! di/ance1 b z ! squ>es ( ! di/ances increase4 ,c>ol9e4 ,i d n exactly compreh5d :at is meant by ! squ>es1 9 ?is case1 al?\gh ,i "k v well :at is 9 g5]al int5d$ by a squ>e4 ,mrs4 ,b4 ,by ! squ>e ( a numb] we mean ! product ( a numb]1 multipli$ by itself2 ?us two1 multipli$ by two1 is f\r1 :i* is !re=e ! squ>e ( two2 9 l mann] ! squ>e ( ?ree1 is n9e1 because ?ree multipli$ by ?ree1 gives t product4 ,emily4 ,!n if "o planet is ?ree times m di/ant f ! sun ?an ano!r1 x w be attract$ ) b "o-n9? "p ( ! =ce2 & if at f\r times ! di/ance1 ) b "o-sixte5?1 sixte5 be+ ! squ>e ( f\r8 ,mrs4 ,b4 ,y are correct2 ! rule is1 t ! attractive =ce is 9 ! inv]se proportion ( ! squ>e ( ! di/ance4 ,& x is easily demon/rat$ by ! ma!matics1 t ! same is ! case ) e p[] t emanates f a c5tre2 z = example1 ! light f ! sun1 or f any o!r lum9\s body1 decreases 9 its int5sity at ! same rate4 ,c>ol9e4 ,!n ! m di/ant planets1 move mu* sl[] 9 _! orbits2 = _! projectile =ce mu/ be proportion$ to t ( attraction8 ,b ,i d n see h[ ?is acc\nts = ! motion ( ! second>y1 r\nd ! prim>y planets1 9 pref]5ce to mov+ r\nd ! sun8 ,emily4 ,is x n because ! vic9ity ( ! prim>y planets1 r5d]s _! attraction /rong] ?an t ( ! sun8 ,mrs4 ,b4 ,exactly s4 ,b s9ce ! attraction betwe5 bodies is mutual1 ! prim>y planets are also attract$ by ! satellites :i* revolve r\nd !m4 ,! moon attracts ! e>?1 z well z ! e>? ! moon2 b z ! latt] is ! small] body1 h] attraction is proportionally less2 !re=e1 nei!r ! e>? revolves r\nd ! moon1 nor ! moon r\nd ! e>?2 b !y bo? revolve r\nd a po9t1 :i* is _! common c5tre ( gravity1 & :i* is z mu* ne>] to ! e>? ?an to ! moon1 z ! gravity ( ! =m] exce$s t ( ! latt]4 ,emily4 ,yes1 ,i recollect y\r say+1 t if two bodies 7 fa/5$ toge!r by a wire or b>1 _! common c5tre ( gravity w\ld be 9 ! middle ( ! b>1 provid$ ! bodies 7 ( equal weight2 & if !y diff]$ 9 weight1 x w\ld be ne>] ! l>g] body4 ,if !n1 ! e>? & moon _h no projectile =ce :i* prev5t$ _! mutual attraction f br++ !m toge!r1 !y w\ld meet at _! common c5tre ( gravity4 ,c>ol9e4 ,! e>? !n has a great v>iety ( motion1 x revolves r\nd ! sun1 r\nd its own axis1 & r\nd ! po9t t[>ds :i* ! moon attracts x4 ,mrs4 ,b4 ,j s2 & ?is is ! case ) e planet :i* is att5d$ by satellites4 ,! complicat$ effect ( ?is v>iety ( motions1 produces c]ta9 irregul>ities1 :i*1 h[ev]1 x is n necess>y to notice at pres5t1 except+ to obs]ve t !y ev5tually correct ea* o!r1 s t no p]man5t d]angem5t exi/s4 ,! planets act on ! sun1 9 ! same mann] z !y are !mselves act$ on by _! satellites2 = attraction1 y mu/ rememb]1 is always mutual2 b ! gravity ( ! planets 7ev5 :5 tak5 collectively7 is s trifl+ comp>$ ) t ( ! sun1 t 7 !y all plac$ on ! same side ( t lum9>y1 !y w\ld n cause him to move s mu* z "o-half ( 8 diamet] t[>ds !m1 & ! common c5tre ( gravity1 w\ld /ill rema9 )9 ! body ( ! sun4 ,! planets d n1 !re=e1 revolve r\nd ! c5tre ( ! sun1 b r\nd a po9t at a small di/ance f its c5tre1 ab\t :i* ! sun also revolves4 ,emily4 ,i ?\ght ! sun _h no motion8 ,mrs4 ,b4 ,y 7 mi/ak52 = besides t r\nd ! common c5tre ( gravity1 :i* ,i h j m5tion$1 :i* is inde$ v inconsid]able1 he revolves on 8 axis 9 ab\t #be days2 ?is motion is asc]ta9$ by obs]v+ c]ta9 spots :i* disappe>1 & reappe> regul>ly at /at$ times4 ,illu/ration3 ,,plate ,,vii4 ,c>ol9e4 ,a planet has frequ5tly be5 po9t$ out to me 9 ! heav5s2 b ,i c\ld n p]ceive t its motion diff]$ f t ( ! fix$ />s1 :i* only appe> to move4 ,mrs4 ,b4 ,! great di/ance ( ! planets1 r5d]s _! app>5t motion s sl[1 t ! eye is n s5sible ( _! progress 9 _! orbits1 unless we wat* !m = "s consid]able l5g? ( "t3 b if y notice ! ne>ness ( a planet to any p>ticul> fix$ />1 y may 9 a few nights p]ceive t x has *ang$ its di/ance f x1 :il/ ! />s !mselves always reta9 _! relative situations4 ,! mo/ accurate idea ,i c give y ( ! situation & motion ( ! planets 9 _! orbits1 w be by ! exam9ation ( ?is diagram1 7plate #g4 fig4 #a47 repres5t+ ! sol> sy/em1 9 :i* y w f9d e planet1 ) its orbit del9eat$4 ,emily4 ,b ! orbits "h are all circul>1 & y said t !y 7 elliptical4 ,! planets appe> too1 to be mov+ r\nd ! c5tre ( ! sun2 :il/ y told u t !y mov$ r\nd a po9t at a little di/ance f !nce4 ,mrs4 ,b4 ,! orbits ( ! planets are s ne>ly circul>1 & ! common c5tre ( gravity ( ! sol> sy/em1 s ne> ! c5tre ( ! sun1 t ^! deviations are too small to be repres5t$4 ,! dim5sions ( ! planets1 9 _! proportion to ea* o!r1 y w f9d del9eat$ 9 fig4 #b4 ,m]cury is ! planet ne>e/ ! sun2 8 orbit is consequ5tly conta9$ )9 ours2 8 vic9ity to ! sun1 prev5ts our frequ5tly see+ him1 s t v accurate obs]vations _c be made ^u ,m]cury4 ,he p]=ms 8 revolution r\nd ! sun 9 ab\t #hg days1 :i* is consequ5tly ! l5g? ( 8 ye>4 ,! "t ( 8 rotation on 8 axis is n kn[n2 8 di/ance f ! sun is comput$ to be #cg millions ( miles1 & 8 diamet] #cahj miles4 ,! heat ( ?is planet is suppos$ to be s great1 t wat] _c exi/ !re b 9 a /ate ( vap\r1 & t ev5 quicksilv] w\ld be made to boil4 ,c>ol9e4 ,oh1 :at a dreadful climate6 ,mrs4 ,b4 ,?\gh we c\ld n live !re1 x may be p]fectly adapt$ to o!r be+s1 de/9$ to inhabit x2 or he :o creat$ x may h s modifi$ ! heat1 by provisions ( :i* we are ignorant1 z to make x habitable ev5 by ourselves4 ,v5us1 ! next 9 ! ord] ( planets1 is #fh millions ( miles f ! sun3 %e revolves ab\t h] axis 9 #bc h\rs & #ba m9utes1 & goes r\nd ! sun 9 #bdd days1 #ag h\rs4 ,! orbit ( ,v5us is also )9 ours2 dur+ ne>ly "o-half ( h] c\rse 9 x1 we see h] be=e sun-rise1 & %e is !n call$ ! morn+ />2 9 ! o!r "p ( h] orbit %e rises lat] ?an ! sun4 ,c>ol9e4 ,9 t case we _c see h]1 = %e mu/ rise 9 ! day "t8 ,mrs4 ,b4 ,true2 b :5 %e rises lat] ?an ! sun1 %e also sets lat]2 s t we p]ceive h] approa*+ ! horizon aft] sun-set3 %e is !n call$ ,hesp]us1 or ! ev5+ />4 ,d y recollect ^? beautiful l9es ( ,milton8 ,n[ came /ill ev5+ on1 & twilight gray ,_h 9 h] sob] liv]y all ?+s clad2 ,sil5ce accompani$2 = bea/ & bird1 ,!y to _! grassy c\*1 ^! to _! ne/s ,7 slunk1 all b ! wakeful night+ale2 ,%e all night long h] amor\s descant sung2 ,sil5ce 0 pleas'd2 n[ gl[$ ! firmam5t ,) liv+ sapphires4 ,hesp]us t l$ ,! />ry ho/1 rode brighte/1 till ! moon ,ris+ 9 cl\d$ maje/y1 at l5g? ,app>5t que5 unveil'd h] pe]less light1 ,& o'er ! d>k h] silv] mantle ?rew4 ,! planet next to ,v5us is ! ,e>?1 ( :i* we %all soon speak at full l5g?4 ,at pres5t ,i %all only obs]ve t we are #ie millions ( miles di/ant f ! sun1 t we p]=m our annual revolution 9 #cfe days #e h\rs & #di m9utes2 & are att5d$ 9 our c\rse by a s+le moon4 ,next foll[s ,m>s4 ,he c nev] come betwe5 u & ! sun1 l ,m]cury & ,v5us2 8 motion is1 h[ev]1 v p]ceptible1 z he may be trac$ to diff]5t situations 9 ! heav5s2 8 di/ance f ! sun is #add millions ( miles2 he turns r\nd 8 axis 9 #bd h\rs & #ci m9utes2 & he p]=ms 8 annual revolution1 9 ab\t #fhg ( our days3 8 diamet] is #dabj miles4 ,!n foll[ f\r v small planets1 ,juno1 ,c]es1 ,pallas & ,ve/a1 :i* h be5 rec5tly discov]$1 b ^: dim5sions1 & di/ances f ! sun1 h n be5 v accurately asc]ta9$4 ,!y are g5]ally call$ a/]oids4 ,jupit] is next 9 ord]3 ?is is ! l>ge/ ( all ! planets4 ,he is ab\t #dij millions ( miles f ! sun1 & completes 8 annual p]iod 9 ne>ly #ab ( our ye>s4 ,he turns r\nd 8 axis 9 ab\t t5 h\rs4 ,he is above #abjj times z big z our e>?2 8 diamet] is #hf1jjj miles4 ,! respective proportions ( ! planets _c1 !re=e1 y see1 be conv5i5tly del9eat$ 9 a diagram4 ,he is att5d$ by f\r moons4 ,! next planet is ,saturn1 ^: di/ance f ! sun1 is ab\t #ijj millions ( miles2 8 diurnal rotation is p]=m$ 9 #aj h\rs & a qu>t]3 8 annual revolution is ne>ly #cj ( our ye>s4 ,8 diamet] is #gi1jjj miles4 ,?is planet is surr\nd$ by a lum9\s r+1 ! nature ( :i*1 a/ronom]s are mu* at a loss to conjecture3 he has sev5 moons4 ,la/ly1 we obs]ve ! planet ,h]s*el1 discov]$ by ,dr4 ,h]s*el1 by :om x 0 nam$ ! ,georgium ,sidus1 & :i* is att5d$ by six moons4 ,c>ol9e4 ,h[ *>m+ x mu/ be 9 ! di/ant planets1 to see sev]al moons %9+ at ! same "t2 ,i ?9k ,i %\ld l to be an inhabitant ( ,jupit] or ,saturn4 ,mrs4 ,b4 ,n long ,i believe4 ,consid] :at extreme cold mu/ prevail 9 a planet1 situat$ z ,saturn is1 at ne>ly t5 times ! di/ance at :i* we are f ! sun4 ,!n 8 num]\s moons are f> f mak+ s spl5did an appe>ance z ours2 = !y c reflect only ! light :i* !y receive f ! sun2 & bo? light1 & heat1 decrease 9 ! same ratio or proportion to ! di/ances1 z gravity4 ,c y tell me n[ h[ mu* m light we enjoy ?an ,saturn8 ,c>ol9e4 ,! squ>e ( t5 is a hundr$2 !re=e1 ,saturn has a hundr$ times less--or to answ] y\r "q exactly1 we h a hundr$ times m light & heat1 ?an ,saturn--?is c]ta9ly does n increase my wi% to become "o ( ! poor wret*es :o inhabit t planet4 ,mrs4 ,b4 ,may n ! inhabitants ( ,m]cury1 ) equal plausibility1 pity u = ! insupportable coldness ( our situation2 & ^? ( ,jupit] & ,saturn = our intol]able heat8 ,! ,almighty p[] :i* creat$ ^! planets1 & plac$ !m 9 _! sev]al orbits1 has no d\bt peopl$ !m ) be+s1 ^: bodies are adapt$ to ! v>i\s temp]atures & elem5ts1 9 :i* !y are situat$4 ,if we judge f ! analogy ( our own e>?1 or f t ( ! great & univ]sal b5efic5ce ( ,provid5ce1 we mu/ conclude ?is to be ! case4 ,c>ol9e4 ,are n comets1 9 "s respects simil> to planets8 ,mrs4 ,b4 ,yes1 !y are2 = by ! reappe>ance ( "s ( !m1 at /at$ times1 !y are kn[n to revolve r\nd ! sun2 b 9 orbits s extremely ecc5tric1 t !y disappe> = a great numb] ( ye>s4 ,if !y are inhabit$1 x mu/ be by a species ( be+s v diff]5t1 n only f ! inhabitants ( ?is1 b f ^? ( any ( ! o!r planets1 z !y mu/ exp]i5ce ! greate/ vicissitudes ( heat & cold2 "o "p ( _! orbit be+ s ne> ! sun1 t _! heat1 :5 !re1 is comput$ to be great] ?an t ( r$-hot iron2 9 ?is "p ( its orbit1 ! comet emits a lum9\s vap\r1 call$ ! tail1 :i* x gradually loses z x rec$es f ! sun2 & ! comet itself totally disappe>s f our sight1 9 ! m di/ant p>ts ( its orbit1 :i* ext5ds consid]ably beyond t ( ! fur!/ planet4 ,! numb] ( comets belong+ to our sy/em _c be asc]ta9$1 z "s ( !m are sev]al c5turies be=e !y make _! reappe>ance4 ,! numb] t are kn[n by _! regul> reappe>ance is1 ,i believe1 only ?ree1 al?\gh _! :ole numb] is v consid]able4 ,emily4 ,pray1 ,mrs4 ,b41 :at are ! con/ellations8 ,mrs4 ,b4 ,!y are ! fix$ />s2 :i* ! anci5ts1 9 ord] to recognise !m1 =m$ into gr\ps1 & gave ! names ( ! figures1 :i* y f9d del9eat$ on ! cele/ial globe4 ,9 ord] to %[ _! prop] situations 9 ! heav5s1 !y %\ld be pa9t$ on ! int]nal surface ( a holl[ sph]e1 f ! c5tre ( :i* y %\ld view !m2 y w\ld !n behold !m z !y appe> to be situat$ 9 ! heav5s4 ,! twelve con/ellations1 call$ ! signs ( ! zodiac1 are ^? :i* are s situat$1 t ! e>?1 9 its annual revolution1 passes directly betwe5 !m1 & ! sun4 ,_! names are ,aries1 ,taurus1 ,gem9i1 ,canc]1 ,leo1 ,virgo1 ,libra1 ,scorpio1 ,sagitt>ius1 ,capricornus1 ,aqu>ius1 ,pisces2 ! :ole occupy+ a complete circle1 or broad belt1 9 ! heav5s1 call$ ! zodiac4 7plate #h4 fig4 #a47 ,h5ce1 a "r l9e drawn f ! e>?1 & pass+ ?r\gh ! sun1 w\ld rea* "o ( ^! con/ellations1 & ! sun is said to be 9 t con/ellation at :i* ! l9e t]m9ates3 ?us1 :5 ! e>? is at ,a1 ! sun w\ld appe> to be 9 ! con/ellation or sign ,aries2 :5 ! e>? is at ,b1 ! sun w\ld appe> 9 ,canc]2 :5 ! e>? 0 at ,c1 ! sun w\ld be 9 ,libra2 & :5 ! e>? 0 at ,d1 ! sun w\ld be 9 ,capricorn4 ,y are aw>e t x is ! real motion ( ! e>? 9 its orbit1 :i* gives to ! sun ?is app>5t motion ?r\gh ! signs4 ,?is circle1 9 :i* ! sun ?us appe>s to move1 & :i* passes ?r\gh ! middle ( ! zodiac1 is call$ ! ecliptic4 ,c>ol9e4 ,b _m ( ! />s 9 ^! con/ellations appe> beyond ! zodiac4 ,illu/ration3 ,,plate ,,viii4 ,mrs4 ,b4 ,we h no means ( asc]ta9+ ! di/ance ( ! fix$ />s4 ,:51 !re=e1 !y are said to be 9 ! zodiac1 x is m]ely impli$ t !y are situat$ 9 t direction1 & t !y %9e ^u u ?r\gh t portion ( ! heav5s1 :i* we call ! zodiac4 ,emily4 ,b are n ^? l>ge bright />s1 :i* are call$ />s ( ! fir/ magnitude1 ne>] to u1 ?an ^? small ones :i* we c sc>cely disc]n8 ,mrs4 ,b4 ,x may be s2 or ! diff]5ce ( size & brilliancy ( ! />s may proce$ f _! diff]5ce ( dim5sions2 ?is is a po9t :i* a/ronom]s are n enabl$ to det]m9e4 ,consid]+ !m z suns1 ,i see no reason :y diff]5t suns %\ld n v>y 9 dim5sions1 z well z ! planets belong+ to !m4 ,emily4 ,:at a wond]ful & beautiful sy/em ?is is1 & h[ a/oni%+ to ?9k t e fix$ /> may probably be att5d$ by a simil> tra9 ( planets6 ,c>ol9e4 ,y w accuse me ( be+ v incr$ul\s1 b ,i _c help /ill ent]ta9+ "s d\bts1 & fe>+ t !re is m beauty ?an tru? 9 ?is sy/em4 ,x c]ta9ly may be s2 b !re does n appe> to me to be suffici5t evid5ce to prove x4 ,x seems s pla9 & obvi\s t ! e>? is motionless1 & t ! sun & />s revolve r\nd x2--y\r sol> sy/em1 y mu/ all[1 is directly 9 opposition to ! evid5ce ( our s5ses4 ,mrs4 ,b4 ,our s5ses s (t5 mislead u1 t we %\ld n place implicit reliance ^u !m4 ,c>ol9e4 ,on :at !n c we rely1 = d we n receive all our ideas ?r\gh ! m$ium ( our s5ses8 ,mrs4 ,b4 ,x is true t !y are our prim>y s\rce ( k2 b ! m9d has ! p[] ( reflect+1 judg+1 & decid+ ^u ! ideas receiv$ by ! organs ( s5se4 ,?is faculty1 :i* we call reason1 has frequ5tly prov$ to u1 t our s5ses are liable to err4 ,if y h ev] sail$ on ! wat]1 ) a v /eady breeze1 y mu/ h se5 ! h\ses1 trees1 & e object on ! %ore move1 :ile y 7 sail+4 ,c>ol9e4 ,i rememb] ?9k+ s1 :5 ,i 0 v "y2 b ,i n[ "k t _! motion is only app>5t4 ,x is true t my reason1 9 ?is case1 corrects ! error ( my sight4 ,mrs4 ,b4 ,x tea*es y1 t ! app>5t motion ( ! objects on %ore1 proce$s f y\r be+ y\rself mov+1 & t y are n s5sible ( y\r own motion1 because y meet ) no resi/ance4 ,x is only :5 "s ob/acle imp$es our motion1 t we are consci\s ( mov+2 & if y 7 to close y\r eyes :5 y 7 sail+ on calm wat]1 ) a /eady w9d1 y w\ld n p]ceive t y mov$1 = y c\ld n feel x1 & y c\ld see x only by obs]v+ ! *ange ( place ( ! objects on %ore4 ,s x is ) ! motion ( ! e>?3 e ?+ on its surface1 & ! air t surr\nds x1 accompanies x 9 its revolution2 x meets ) no resi/ance3 !re=e1 l ! crew ( a vessel sail+ ) a fair w9d1 9 a calm sea1 we are ins5sible ( our motion4 ,c>ol9e4 ,b ! pr9cipal reason :y ! crew ( a vessel 9 a calm sea d n p]ceive _! motion1 is1 because !y move exce$+ly sl[1 :ile ! e>?1 y say1 revolves ) great velocity4 ,mrs4 ,b4 ,x is n because !y move sl[ly1 b because !y move /eadily1 & meet ) no irregul> resi/ances1 t ! crew ( a vessel d n p]ceive _! motion2 = !y w\ld be equally ins5sible to x1 ) ! /ronge/ w9d1 provid$ x 7 /eady1 t !y sail$ ) x1 & t x did n agitate ! wat]2 b ?is la/ condition1 y "k1 is n possible1 = ! w9d w always produce waves :i* (f] m or less resi/ance to ! vessel1 & !n ! motion becomes s5sible1 because x is unequal4 ,c>ol9e4 ,b1 grant+ ?is1 ! crew ( a vessel h a pro( ( _! motion1 :i* ! inhabitants ( ! e>? _c h1--! app>5t motion ( ! objects on %ore1 or _! hav+ pass$ f "o place to ano!r4 ,mrs4 ,b4 ,h we n a simil> pro( ( ! e>?'s motion1 9 ! app>5t motion ( ! sun & />s8 ,imag9e ! e>? to be sail+ r\nd its axis1 & successively pass+ by e />1 :i*1 l ! objects on l&1 we suppose to be mov+ in/ead ( ourselves4 ,i h he>d x obs]v$ by an a]ial travell] 9 a balloon1 t ! e>? appe>s to s9k b5ea? ! balloon1 in/ead ( ! balloon ris+ above ! e>?4 ,x is a law :i* we discov] ?r\gh\t nature1 & wor?y ( its great ,au?or1 t all its purposes are accompli%$ by ! mo/ simple means2 & :at reason h we to suppose ?is law infr+$1 9 ord] t we may rema9 at re/1 :ile ! sun & />s move r\nd u2 _! regul> motions1 :i* are expla9$ by ! laws ( attraction1 on ! fir/ supposition1 w\ld be un9telligible on ! la/1 & ! ord] & h>mony ( ! univ]se be de/roy$4 ,?9k :at an imm5se circuit ! sun & />s w\ld make daily1 7 _! app>5t motions1 real4 ,we "k _m ( !m1 to be bodies m consid]able ?an our e>?2 = our eyes va9ly endeav\r to p]suade u1 t !y are little brilliants sp>kl+ 9 ! heav5s2 :ile sci5ce tea*es u t !y are imm5se sph]es1 ^: app>5t dim5sions are dim9i%$ by di/ance4 ,:y !n %\ld ^! enorm\s globes daily trav]se su* a prodigi\s space1 m]ely to prev5t ! necessity ( our e>?'s revolv+ on its axis8 ,c>ol9e4 ,i ?9k ,i mu/ n[ be conv9c$4 ,b y w1 ,i hope1 all[ me a little "t to famili>ise to myself1 an idea s diff]5t f t :i* ,i h be5 accu/om$ to ent]ta94 ,& pray1 at :at rate d we move8 ,mrs4 ,b4 ,! motion produc$ by ! revolution ( ! e>? on its axis1 is ab\t sev5te5 miles a m9ute1 to an inhabitant on ! equator4 ,emily4 ,b does n e "p ( ! e>? move ) ! same velocity8 ,mrs4 ,b4 ,a mom5t's reflection w\ld conv9ce y ( ! contr>y3 a p]son at ! equator mu/ move quick] ?an "o situat$ ne> ! poles1 s9ce !y bo? p]=m a revolution 9 #bd h\rs4 ,emily4 ,true1 ! equator is f>!/ f ! axis ( motion4 ,b 9 ! e>?'s revolution r\nd ! sun1 e "p mu/ move ) equal velocity8 ,mrs4 ,b4 ,yes1 ab\t a ?\s& miles a m9ute4 ,c>ol9e4 ,h[ a/oni%+6--& t x %\ld be possible = u to be ins5sible ( su* a rapid motion4 ,y w\ld n tell me ?is soon]1 ,mrs4 ,b41 = fe> ( increas+ my incr$ulity4 ,be=e ! "t ( ,newton1 0 n ! e>? suppos$ to be 9 ! c5tre ( ! sy/em1 & ! sun1 moon1 & />s to revolve r\nd x8 ,mrs4 ,b4 ,?is 0 ! sy/em ( ,ptolemy1 9 anci5t times2 b z long ago z ! beg9n+ ( ! sixte5? c5tury x 0 g5]ally disc>d$1 & ! sol> sy/em1 su* z ,i h %[n y1 0 e/abli%$ by ! celebrat$ a/ronom] ,cop]nicus1 & is h5ce call$ ! ,cop]nican sy/em4 ,b ! !ory ( gravitation1 ! s\rce f :i* ?is beautiful & h>moni\s arrangem5t fl[s1 we owe to ! p[]ful g5ius ( ,newton1 :o liv$ at a mu* lat] p]iod1 & :o demon/rat$ its tru?4 ,emily4 ,x appe>s1 inde$1 f> less difficult to trace by obs]vation ! motion ( ! planets1 ?an to div9e by :at p[] !y are impell$ & guid$4 ,i wond] h[ ! idea ( gravitation c\ld fir/ h occurr$ to sir ,isaac ,newton8 ,mrs4 ,b4 ,x is said to h be5 occasion$ by a circum/ance f :i* "o %\ld little h expect$ s gr& a !ory to h aris54 ,dur+ ! preval5ce ( ! plague 9 ! ye> #affe1 ,newton retir$ into ! c\ntry to avoid ! contagion3 :5 sitt+ "o day 9 an or*>d1 he obs]v$ an apple fall f a tree1 & 0 l$ to consid] :at c\ld be ! cause :i* br\ght x to ! gr\nd4 ,c>ol9e4 ,if ,i d>$ to confess x1 ,mrs4 ,b41 ,i %\ld say t su* an inquiry indicat$ r a defici5cy ?an a sup]iority ( intellect4 ,i d n und]/& h[ any "o c wond] at :at is s natural & s common4 ,mrs4 ,b4 ,x is ! m>k ( sup]ior g5ius to f9d matt] = wond]1 obs]vation1 & rese>*1 9 circum/ances :i*1 to ! ord9>y m9d1 appe> trivial1 because !y are common2 & ) :i* !y are satisfi$1 because !y are natural2 )\t reflect+ t nature is our gr& field ( obs]vation1 t )9 x1 is conta9$ our :ole /ore ( k2 9 a ^w1 t to /udy ! works ( nature1 is to le>n to appreciate & admire ! wisdom ( ,god4 ,?us1 x 0 ! simple circum/ance ( ! fall ( an apple1 :i* l$ to ! discov]y ( ! laws ^u :i* ! ,cop]nican sy/em is f\nd$2 & :atev] cr$it ?is sy/em _h obta9$ be=e1 x n[ re/s ^u a basis f :i* x _c be %ak54 ,emily4 ,?is 0 a mo/ =tunate apple1 & m wor?y to be commemorat$ ?an all ^? t h be5 sung by ! poets4 ,! apple ( discord = :i* ! goddesses cont5d$2 ! gold5 apples by :i* ,atalanta won ! race2 nay1 ev5 ! apple :i* ,william ,tell %ot f ! head ( 8 son1 _c be comp>$ to ?is6 ,que/ions #a4 7,pg4 #hj7 ,into :at two classes are ! planets divid$1 & h[ are !y di/+ui%$8 #b4 7,pg4 #hj7 ,by :at reason+ d y prove t ! sun conta9s a great] quantity ( matt] ?an any o!r body 9 ! sy/em8 #c4 7,pg4 #ha7 ,:at two circum/ances gov]n ! =ce ) :i* bodies attract ea* o!r8 #d4 7,pg4 #ha7 ,7 a planet remov$ to d\ble its =m] di/ance f ! sun1 :at w\ld be ! effect ^u its attractive =ce8 #e4 7,pg4 #ha7 ,:y w\ld x be r$uc$ to "o-f\r?8 #f4 7,pg4 #ha7 ,:at is meant by ! squ>e ( a numb]1 & :at examples c y give8 #g4 7,pg4 #ha7 ,:at !n w\ld be ! effect ( remov+ x to ?ree1 or f\r times its =m] di/ance8 #h4 7,pg4 #ha7 ,h[ is ! rule ^u ?is subject express$8 #i4 7,pg4 #ha7 ,does ?is apply to any p[] except+ gravitation8 #aj4 7,pg4 #ha7 ,h[ is x t a second>y planet revolves r\nd its prim>y1 & is n drawn (f by ! sun8 #aa4 7,pg4 #hb7 ,:at is said respect+ ! revolution ( ! moon1 & ( ! e>?1 r\nd a common c5tre ( gravity8 #ab4 7,pg4 #hb7 ,by :at law 9 me*anics is ?is expla9$8 #ac4 7,pg4 #hb7 ,:at motions !n has ! e>?1 & are ^! rem>ks conf9$ to x alone8 #ad4 7,pg4 #hb7 ,:at effect h ! planets ^u ! sun1 & :at is said ( ! common c5tre ( gravity ( ! sy/em8 #ae4 7,pg4 #hc7 ,:at o!r motion has ! sun1 & h[ is x prov$8 #af4 7,pg4 #hc7 ,h[ may y obs]ve ! motion ( a planet1 by means ( a fix$ />8 #ag4 7,pg4 #hc7 ,:at is repres5t$ by fig4 #a4 plate #g8 #ah4 7,pg4 #hc7 ,:y are ! orbits repres5t$ z circul>8 #ai4 7,pg4 #hc7 ,9 :at ord] d ! planets increase 9 size z repres5t$1 fig4 #b4 plate #g8 #bj4 7,pg4 #hc7 ,:at are we told respect+ ,m]cury8 #ba4 7,pg4 #hd7 ,:at respect+ ,v5us8 #bb4 7,pg4 #hd7 ,:5 does ,v5us become a morn+1 & :5 an ev5+ />8 #bc4 7,pg4 #hd7 ,:at is said ( ! ,e>?8 #bd4 7,pg4 #hd7 ,:at ( ,m>s8 #be4 7,pg4 #hd7 ,:at f\r small planets foll[ next8 #bf4 7,pg4 #he7 ,:at is said ( ,jupit]8 #bg4 7,pg4 #he7 ,:at ( ,saturn8 #bh4 7,pg4 #he7 ,:at ( ,h]s*el8 #bi4 7,pg4 #he7 ,:y d we conclude t ! moons ( ,saturn af=d less light ?an ours8 #cj4 7,pg4 #he7 ,9 :at proportion w ! light & heat at ,saturn be dim9i%$1 & :y8 #ca4 7,pg4 #hf7 ,:at d ! comets resemble1 & :at is rem>kable 9 _! orbits8 #cb4 7,pg4 #hf7 ,:at is said ( ! numb] ( comets8 #cc4 7,pg4 #hf7 ,:at is a con/ellation8 #cd4 7,pg4 #hf7 ,h[ are ! twelve con/ellations1 or signs1 call$ ! zodiac1 situat$8 #ce4 7,pg4 #hf7 ,"n !m4 #cf4 7,pg4 #hf7 ,:at is meant by ! sun be+ 9 a sign8 #cg4 7,pg4 #hf7 ,:at causes ! app>5t *ange ( ! sun's place8 #ch4 7,pg4 #hg7 ,! />s appe> ( diff]5t magnitudes1 by :at may ?is be caus$8 #ci4 7,pg4 #hg7 ,we are n s5sible ( ! motion ( ! e>?2 :at fact is m5tion$ to illu/rate ?is po9t8 #dj4 7,pg4 #hg7 ,:at does ?is tea* u8 #da4 7,pg4 #hh7 ,w\ld ! sl[ness1 or ! rapidity ( ! motion1 if /eady1 produce any s5sible diff]5ce8 #db4 7,pg4 #hh7 ,if we d n feel ! motion ( ! e>?1 h[ may we be conv9c$ ( its reality8 #dc4 7,pg4 #hi7 ,7 we to d5y ! motion ( ! e>? ^u its axis1 :at mu/ we admit respect+ ! heav5ly bodies8 #dd4 7,pg4 #hi7 ,:at di/ance is an inhabitant on ! equator c>ri$ 9 a m9ute by ! diurnal motion ( ! e>?8 #de4 7,pg4 #hi7 ,:y is n ! velocity e :]e equally great8 #df4 7,pg4 #hi7 ,:at di/ance does ! e>? travel 9 a m9ute1 9 its revolution r\nd ! sun8 #dg4 7,pg4 #hi7 ,:at 0 =m]ly suppos$ respect+ ! motion ( all ! heav5ly bodies8 #dh4 7,pg4 #hi7 ,:at d we mean by ! ,cop]nican sy/em1 & :at is said respect+ ,cop]nicus & ,newton8 #di4 7,pg4 #ij7 ,:at circum/ance is said to h giv5 rise to ! speculations ( ,newton1 on ! subject ( gravitation8 ,,conv]sation ,,viii4 ,,on ,,! ,,e>?4 ,,( ,,! ,,t]re/rial ,,globe4 ,,( ,,! ,,figure ,,( ,,! ,,e>?4 ,,( ,,! ,,p5dulum4 ,,( ,,! ,,v>iation ,,( ,,! ,,seasons1 ,,& ,,( ,,! ,,l5g? ,,( ,,days ,,& ,,nights4 ,,( ,,! ,,causes ,,( ,,! ,,heat ,,( ,,summ]4 ,,( ,,sol>1 ,,sid]ial1 ,,& ,,equal ,,or ,,mean ,,"t4 ,,mrs4 ,b4 ,z ! e>? is ! planet 9 :i* we are ! mo/ p>ticul>ly int]e/$1 x is my int5tion ?is morn+1 to expla9 to y ! effects result+ f its annual1 & diurnal motions2 b = ?is purpose1 x w be necess>y to make y acqua9t$ ) ! t]re/rial globe3 y h n ei!r ( y1 ,i conclude1 le>nt ! use ( ! globes8 ,c>ol9e4 ,no2 ,i once inde$1 le>nt by he>t1 ! names ( ! l9es m>k$ on ! globe1 b z ,i 0 in=m$ !y 7 only imag9>y divisions1 !y did n appe> to me wor?y ( mu* att5tion1 & 7 soon =gott54 ,mrs4 ,b4 ,y suppos$1 !n1 t a/ronom]s _h be5 at ! tr\ble ( inv5t+ a numb] ( l9es1 to little purpose4 ,x w be impossible = me to expla9 to y ! p>ticul> effects ( ! e>?'s motion1 )\t y\r hav+ acquir$ a k ( ^! l9es3 9 plate #h4 fig4 #b4 y w f9d !m all del9eat$3 & y mu/ le>n !m p]fectly1 if y wi% to make any pr(ici5cy 9 a/ronomy4 ,c>ol9e4 ,i 0 taught !m at s e>ly an age1 t ,i c\ld n und]/& _! mean+2 & ,i h (t5 he>d y say1 t ! only use ( words1 0 to convey ideas4 ,mrs4 ,b4 ,a k ( ^! l9es1 w\ld h convey$ "s idea ( ! mann] 9 :i* !y 7 design$ to divide ! globe into p>ts2 al?\gh ! use ( ^! divisions1 might at t "t1 h be5 too difficult = y to und]/&4 ,*ildhood is ! season1 :5 impressions on ! memory are mo/ /rongly & mo/ easily made3 x is ! p]iod at :i* a l>ge /ock ( t]ms %\ld be treasur$ up1 ! precise application ( :i* we may le>n :5 ! und]/&+ is m develop$4 ,x is1 ,i ?9k1 a v mi/ak5 notion1 t *ildr5 %\ld be taught su* ?+s only1 z !y c p]fectly und]/&4 ,_h y be5 e>ly made acqua9t$ ) ! t]ms :i* relate to figure & motion1 h[ mu* x w\ld h facilitat$ y\r progress 9 natural philosophy4 ,i h be5 oblig$ to conf9e myself to ! mo/ common & famili> expressions1 9 expla9+ ! laws ( nature2 al?\gh ,i am conv9c$ t appropriate & sci5tific t]ms1 might h convey$ m precise & accurate ideas1 _h y be5 prep>$ to und]/& !m4 ,emily4 ,y may dep5d ^u our c>efully le>n+ ! names ( ^! l9es1 ,mrs4 ,b42 b be=e we commit !m to memory1 w y h ! goodness to expla9 !m to u8 ,mrs4 ,b4 ,mo/ will+ly4 ,?is figure ( a globe1 or sph]e1 repres5ts ! e>?2 ! l9e :i* passes ?r\gh its c5tre1 & on :i* x turns1 is call$ its axis1 & ! two extremities ( ! axis ,a & ,b1 are ! poles1 di/+ui%$ by ! names ( ! nor? & ! s\? pole4 ,! circle ,c ,d1 :i* divides ! globe into two equal p>ts betwe5 ! poles1 & equally di/ant f !m1 is call$ ! equator1 or equ9octial l9e2 t "p ( ! globe to ! nor? ( ! equator1 is ! nor!rn hemisph]e2 t "p to ! s\? ( ! equator1 ! s\!rn hemisph]e4 ,! small circle ,e ,f1 :i* surr\nds ! nor? pole1 is call$ ! arctic circle2 t ,g ,h1 :i* surr\nds ! s\? pole1 ! ant>ctic circle2 ^! are also call$ pol> circles4 ,!re are two circles1 int]m$iate betwe5 ! pol> circles & ! equator2 t to ! nor? ,i ,k1 call$ ! tropic ( ,canc]2 t to ! s\?1 ,l ,m1 call$ ! tropic ( ,capricorn4 ,la/ly1 ?is circle1 ,l ,k1 :i* divides ! globe into two equal p>ts1 cross+ ! equator & ext5d+ nor?w>d z f> z ! tropic ( ,canc]1 & s\?w>d z f> z ! tropic ( ,capricorn1 is call$ ! ecliptic4 ,! del9eation ( ! ecliptic on ! t]re/rial globe is n )\t dang] ( convey+ false ideas2 = ! ecliptic 7z ,i h be=e said7 is an imag9>y circle 9 ! heav5s1 pass+ ?r\gh ! middle ( ! zodiac1 & situat$ 9 ! plane ( ! e>?'s orbit4 ,c>ol9e4 ,i d n und]/& ! mean+ ( ! plane ( ! e>?'s orbit4 ,mrs4 ,b4 ,a plane1 is an ev5 flat surface4 ,7 y to b5d a piece ( wire1 s z to =m a hoop1 y might !n /ret* a piece ( clo?1 or pap] ov] x1 l ! head ( a drum2 ?is w\ld =m a flat surface1 :i* might be call$ ! plane ( ! hoop4 ,n[ ! orbit ( ! e>?1 is an imag9>y circle1 surr\nd+ ! sun1 & y c readily imag9e a plane ext5d+ f "o side ( ?is circle to ! o!r1 fill+ up its :ole area3 su* a plane w\ld pass ?r\gh ! c5tre ( ! sun1 divid+ x into hemisph]es4 ,y may !n imag9e ?is plane ext5d$ beyond ! limits ( ! e>?'s orbit1 on e side1 until x rea*$ ^? fix$ />s :i* =m ! signs ( ! zodiac2 pass+ ?r\gh ! middle ( ^! signs1 x w\ld give y ! place ( t imag9>y circle 9 ! heav5s1 call ! ecliptic2 :i* is ! sun's app>5t pa?4 ,let fig4 #a4 plate #i1 repres5t su* a plane1 ,s ! sun1 ,e ! e>? ) its orbit1 & ,a ,b ,c ,d ! ecliptic pass+ ?r\gh ! middle ( ! zodiac4 ,illu/ration3 ,,plate ,,ix4 ,emily4 ,if ! ecliptic relates only to ! heav5s1 :y is x describ$ ^u ! t]re/rial globe8 ,mrs4 ,b4 ,x is conv5i5t = ! demon/ration ( a v>iety ( problems 9 ! use ( ! globes2 & besides1 ! obliquity ( ?is circle to ! equator is r5d]$ m conspicu\s by its be+ describ$ on ! same globe2 & ! obliquity ( ! ecliptic %[s h[ mu* ! e>?'s axis is incl9$ to ! plane ( its orbit4 ,b to return to fig4 #b4 plate #h4 ,! spaces betwe5 ! sev]al p>allel circles on ! t]re/rial globe are call$ zones3 t :i* is compreh5d$ betwe5 ! tropics is di/+ui%$ by ! "n ( ! torrid zone2 ! spaces :i* ext5d f ! tropics to ! pol> circles1 ! nor? & s\? temp]ate zones2 & ! spaces conta9$ )9 ! pol> circles1 ! frigid zones4 ,by ! t]m zone is meant a belt1 or girdle1 ! frigid zones1 h[ev]1 are n belts1 b circles1 ext5d+ #bc-a_/b degrees f _! c5tres1 ! poles4 ,! sev]al l9es :i*1 y obs]ve to be drawn f "o pole to ! o!r1 cutt+ ! equator at "r angles1 are call$ m]idians2 ! numb] ( ^! is unlimit$1 z a l9e pass+ ?r\gh any place1 directly to ! poles1 is call$ ! m]idian ( t place4 ,:5 any "o ( ^! m]idians is exactly opposite to ! sun1 x is mid-day1 or twelve o'clock 9 ! day1 at all ! places situat$ any :]e on t m]idian2 &1 at ! places situat$ on ! opposite m]idian1 x is consequ5tly midnight4 ,emily4 ,to places situat$ equally di/ant f ^! two m]idians1 x mu/ !n be six o'clock4 ,mrs4 ,b4 ,yes2 if !y are to ! ea/ ( ! sun's m]idian x is six o'clock 9 ! aft]noon1 because !y w h previ\sly pass$ ! sun2 if to ! we/1 x is six o'clock 9 ! morn+1 & t m]idian w be proce$+ t[>ds ! sun4 ,^? circles :i* divide ! globe into two equal p>ts1 su* z ! equator & ! ecliptic1 are call$ great] circles2 to di/+ui% !m f ^? :i* divide x into two unequal p>ts1 z ! tropics1 & pol> circles1 :i* are call$ less] circles4 ,all circles1 y "k1 are imag9$ to be divid$ into #cfj equal p>ts1 call$ degrees1 & degrees are aga9 divid$ into #fj equal p>ts1 call$ m9utes4 ,! diamet] ( a circle is a "r l9e drawn across x1 & pass+ ?r\gh its c5tre2 7 y1 = in/ance1 to measure across ?is r\nd table1 t w\ld give y its diamet]2 b 7 y to measure all r\nd ! edge ( x1 y w\ld !n obta9 its circumf]5ce4 ,n[ ,emily1 y may tell me exactly h[ _m degrees are conta9$ 9 a m]idian8 ,emily4 ,a m]idian1 rea*+ f "o pole to ! o!r1 is half a circle1 & mu/ !re=e conta9 #ahj degrees4 ,mrs4 ,b4 ,v well2 & :at numb] ( degrees are !re f ! equator to "o ( ! poles8 ,c>ol9e4 ,! equator be+ equally di/ant f ei!r pole1 t di/ance mu/ be half ( a m]idian1 or a qu>t] ( ! circumf]5ce ( a circle1 & conta9 #ij degrees4 ,mrs4 ,b4 ,besides ! usual division ( circles into degrees1 ! ecliptic is divid$ into twelve equal p>ts1 call$ signs1 :i* be> ! "n ( ! con/ellations ?r\gh :i* ?is circle passes 9 ! heav5s4 ,! degrees measur$ on ! m]idians f ! equator1 ei!r t[>ds ! nor?1 or t[>ds ! s\?1 are call$ degrees ( latitude1 ( :i* !re may be #ij2 ^? measur$ f ea/ to we/1 ei!r on ! equator1 or any ( ! less] circles1 are call$ degrees ( longitude1 ( :i* !re may be #ahj2 ^! less] circles are also call$ p>allels ( latitude4 ,( ^! p>allels !re may be any numb]2 a circle drawn f ea/ to we/1 at any di/ance f ! equator1 w always be p>allel to x1 & is !re=e call$ a p>allel ( latitude4 ,emily4 ,! degrees ( longitude mu/ !n v>y 9 l5g?1 accord+ to ! dim5sions ( ! circle on :i* !y are reckon$2 ^?1 = in/ance1 at ! pol> circles1 w be consid]ably small] ?an ^? at ! equator8 ,mrs4 ,b4 ,c]ta9ly2 s9ce ! degrees ( circles ( diff]5t dim5sions d n v>y 9 numb]1 !y mu/ necess>ily v>y 9 l5g?4 ,! degrees ( latitude1 y may obs]ve1 nev] v>y 9 l5g?2 = ! m]idians on :i* !y are reckon$ are all ( ! same dim5sions4 ,emily4 ,& ( :at l5g? is a degree ( latitude8 ,mrs4 ,b4 ,sixty geographical miles1 :i* is equal to #fi-a_/b ,engli% /atute miles2 or ab\t "o-six? m ?an a common mile4 ,emily4 ,! degrees ( longitude at ! equator1 mu/ !n be ( ! same dim5sions1 ) a degree ( latitude4 ,mrs4 ,b4 ,!y w\ld1 7 ! e>? a p]fect sph]e2 b x is n exactly su*1 be+ some:at protub]ant ab\t ! equator1 & flatt5$ t[>ds ! poles4 ,?is =m proce$s f ! sup]ior action ( ! c5trifugal p[] at ! equator1 & z ?is enl>ges ! circle1 x mu/1 9 ! same proportion1 increase ! l5g? ( ! degrees ( longitude measur$ on x4 ,c>ol9e4 ,i ?\ght ,i _h und]/ood ! c5trifugal =ce p]fectly1 b ,i d n compreh5d its effects 9 ?is in/ance4 ,mrs4 ,b4 ,y "k t ! revolution ( ! e>? on its axis1 mu/ give to e p>ticle a t5d5cy to fly (f f ! c5tre1 t ?is t5d5cy is /rong]1 or weak]1 9 proportion to ! velocity ) :i* ! p>ticle moves2 n[ a p>ticle situat$ ne> to "o ( ! poles1 makes "o rotation 9 ! same space ( "t z a p>ticle at ! equator2 ! latt]1 !re=e1 hav+ a mu* l>g] circle to describe1 travels proportionally fa/]1 consequ5tly ! c5trifugal =ce is mu* /rong] at ! equator ?an 9 ! pol> regions3 x gradually decreases z y leave ! equator & approa* ! poles1 at :i* po9ts ! c5trifugal =ce1 entirely ceases4 ,suppos+1 !re=e1 ! e>? to h be5 orig9ally 9 a fluid /ate1 ! p>ticles 9 ! torrid zone w\ld rec$e mu* f>!r f ! c5tre ?an ^? 9 ! frigid zones2 ?us ! pol> regions w\ld become flatt5$1 & ^? ab\t ! equator elevat$4 ,z a l>ge portion ( ! e>? is cov]$ ) wat]1 ! ,creator gave to x ! =m1 d5om9at$ an oblate sph]oid1 o!rwise ! pol> regions w\ld h be5 )\t wat]1 & ^? ab\t ! equator1 w\ld h be5 buri$ sev]al miles bel[ ! surface ( ! ocean4 ,c>ol9e4 ,i did n consid] t ! p>ticles 9 ! neighb\rhood ( ! equator1 move ) great] velocity ?an ^? ab\t ! poles2 ?is 0 ! reason ,i c\ld n und]/& y4 ,mrs4 ,b4 ,y mu/ be c>eful to rememb]1 t ^? p>ts ( a body :i* are f>!/ f ! c5tre ( motion1 mu/ move ) ! greate/ velocity3 ! axis ( ! e>? is ! c5tre ( its diurnal motion1 & ! equatorial regions ! p>ts mo/ di/ant f ! axis4 ,c>ol9e4 ,my head !n moves fa/] ?an my feet2 & ^u ! summit ( a m\nta91 we are c>ri$ r\nd quick] ?an 9 a valley8 ,mrs4 ,b4 ,c]ta9ly2 y\r head is m di/ant f ! c5tre ( motion ?an y\r feet2 ! m\nta9-top ?an ! valley2 & ! m di/ant any "p ( a body is f ! c5tre ( motion1 ! l>g] is ! circle x w describe1 & ! great] !re=e mu/ be its velocity4 ,emily4 ,i h be5 reflect+1 t if ! e>? is n a p]fect circle---- ,mrs4 ,b4 ,a sph]e y mean1 my de>3 a circle is a r\nd l9e1 e "p ( :i* is equally di/ant f ! c5tre2 a sph]e or globe is a r\nd body1 ! surface ( :i* is e :]e equally di/ant f ! c5tre4 ,emily4 ,if1 !n1 ! e>? is n a p]fect sph]e1 b prom95t at ! equator1 & depress$ at ! poles1 w\ld n a body weigh heavi] at ! equator ?an at ! poles8 ,= ! e>? be+ ?ick] at ! equator1 ! attraction ( gravity p]p5dicul>ly d[nw>ds mu/ be /rong]4 ,mrs4 ,b4 ,y\r reason+ has "s plausibility1 b ,i am sorry to be oblig$ to add1 t x is q errone\s2 = ! ne>] any "p ( ! surface ( a body is to ! c5tre ( attraction1 ! m /rongly x is attract$2 because x is !n ne>e/ to ! :ole mass ( attract+ matt]4 ,9 reg>d to its effects1 y might consid] ! :ole p[] ( gravity1 z plac$ at ! c5tre ( attraction4 ,emily4 ,b 7 y to p5etrate deep into ! e>?1 w\ld gravity increase z y approa*$ ! c5tre8 ,mrs4 ,b4 ,c]ta9ly n2 ,i am ref]r+ only to any situation on ! surface ( ! e>?4 ,7 y to p5etrate into ! int]ior1 ! attraction ( ! p>ts above y1 w\ld c\nt]act t ( ! p>ts b5ea? y1 & consequ5tly dim9i% ! p[] ( gravity 9 proportion z y approa* ! c5tre2 & if y rea*$ t po9t1 be+ equally attract$ by ! p>ts all ar\nd y1 ! effects ( gravity w\ld cease1 & y w\ld be )\t weight4 ,emily4 ,bodies1 !n1 %\ld weigh less at ! equator ?an at ! poles1 s9ce !y are m di/ant f ! c5tre ( gravity 9 ! =m] ?an 9 ! latt] situation8 ,mrs4 ,b4 ,& ?is is really ! case2 b ! diff]5ce ( weight w\ld be sc>cely s5sible1 7 x n augm5t$ by ano!r circum/ance4 ,c>ol9e4 ,& :at is ?is s+ul> circum/ance1 :i* seems to di/urb ! laws ( nature8 ,mrs4 ,b4 ,"o t y are well acqua9t$ )1 z conduc+ m to ! pres]vation ?an ! de/ruction ( ord]1--! c5trifugal =ce4 ,?is we h j obs]v$ to be /ronge/ at ! equator2 & z x t5ds to drive bodies f ! c5tre1 x is necess>ily oppos$ to1 & mu/ less5 ! p[] ( gravity1 :i* attracts !m t[>ds ! c5tre4 ,we accord+ly f9d t bodies weigh lighte/ at ! equator1 :]e ! c5trifugal =ce is greate/2 & heavie/ at ! poles1 :]e ?is p[] is lea/3 ! weight be+ dim9i%$ at ! equator1 by bo? ! causes m5tion$4 ,c>ol9e4 ,has ! exp]im5t be5 made 9 ^! diff]5t situations8 ,mrs4 ,b4 ,l\is ,,xiv4 ( ,france1 s5t philosoph]s bo? to ! equator1 & to ,lapl&1 = ?is purpose3 ! sev]ity ( ! climate1 & ob/ruction f ! ice1 h hi!rto r5d]$ e attempt to rea* ! pole abortive2 b ! diff]5ce ( gravity at ! equator1 & 9 ,lapl& is v p]ceptible4 ,c>ol9e4 ,yet ,i d n compreh5d h[ ! diff]5ce ( weight c\ld be asc]ta9$1 = if ! body "u trial decreas$ 9 weight1 ! weight :i* 0 oppos$ to x 9 ! opposite scale mu/ h dim9i%$ 9 ! same proportion4 ,= in/ance1 if a p\nd ( sug> did n weigh s heavy at ! equator z at ! poles1 ! lead5 p\nd :i* s]v$ to weigh x1 w\ld n be s heavy ei!r2 !re=e !y w\ld /ill balance ea* o!r1 & ! diff]5t =ce ( gravity c\ld n be asc]ta9$ by ?is means4 ,mrs4 ,b4 ,y\r obs]vation is p]fectly j3 ! diff]5ce ( gravity 9 bodies situat$ at ! poles1 & at ! equator1 _c be asc]ta9$ by weigh+ !m2 a p5dulum 0 !re=e us$ = t purpose4 ,c>ol9e4 ,:at1 ! p5dulum ( a clock8 h[ c\ld t answ] ! purpose8 ,mrs4 ,b4 ,a p5dulum consi/s ( a l9e1 or rod1 to "o end ( :i* a weight is atta*$1 & by ! o!r end x is susp5d$ to a fix$ po9t1 ab\t :i* x is made to vibrate4 ,:5 n 9 motion1 a p5dulum1 obey+ ! g5]al law ( attraction1 hangs l a plumb l9e1 p]p5dicul> to ! surface ( ! e>?1 b if y raise ! p5dulum1 gravity w br+ x back to its p]p5dicul> position4 ,x w1 h[ev]1 n rema9 /ation>y !re1 = ! mom5tum x has acquir$ dur+ its desc5t1 w impel x onw>ds1 & if unob/ruct$1 x w rise on ! opposite side to an equal height2 f !nce x is br\ght back by gravity1 & is aga9 =c$ upw>ds1 by ! impulse ( its mom5tum4 ,c>ol9e4 ,if s1 ! motion ( a p5dulum w\ld be p]petual1 & ,i ?\ght y said1 t !re 0 no p]petual motion on ! e>?4 ,mrs4 ,b4 ,! motion ( a p5dulum is oppos$ by ! resi/ance ( ! air 9 :i* x vibrates1 & by ! friction ( ! "p by :i* x is susp5d$3 7 x possible to remove ^! ob/acles1 ! motion ( a p5dulum w\ld be p]petual1 & its vibrations p]fectly regul>2 ea* be+ ( equal di/ance1 & p]=m$ 9 equal times4 ,emily4 ,t is ! natural result ( ! uni=mity ( ! p[] :i* produces ^! vibrations1 = ! =ce ( gravity be+ always ! same1 ! velocity ( ! p5dulum mu/ consequ5tly be uni=m4 ,c>ol9e4 ,no1 ,emily1 y are mi/ak52 ! =ce is n e :]e ! same1 & !re=e ! effect w n be s ei!r4 ,i h discov]$ x1 ,mrs4 ,b42 s9ce ! =ce ( gravity is less at ! equator ?an at ! poles1 ! vibrations ( ! p5dulum w be sl[] at ! =m] place ?an at ! latt]4 ,mrs4 ,b4 ,y are p]fectly "r1 ,c>ol9e2 x 0 by ?is means t ! diff]5ce ( gravity 0 discov]$1 & ! true figure ( ! e>? asc]ta9$4 ,emily4 ,b h[ d !y contrive to regulate _! "t 9 ! equatorial & pol> regions8 =1 s9ce 9 our "p ( ! e>? ! p5dulum ( a clock vibrates exactly once 9 a second1 if x vibrates fa/] at ! poles1 & sl[] at ! equator1 ! inhabitants mu/ regulate _! clocks 9 a mann] diff]5t f u4 ,mrs4 ,b4 ,! only alt]ation requir$ is to l5g!n ! p5dulum 9 "o case1 & to %ort5 x 9 ! o!r2 = ! velocity ( ! vibrations ( a p5dulum dep5ds on its l5g?2 & :5 x is said t a p5dulum vibrates quick] at ! pole ?an at ! equator1 x is suppos$ to be ( ! same l5g?4 ,a p5dulum :i* vibrates seconds 9 ?is latitude is ab\t #ci-a_/g in*es long4 ,9 ord] to vibrate at ! equator 9 ! same space ( "t1 x mu/ be some:at %ort]2 & at ! poles1 x mu/ be proportionally l5g!n$4 ,! vibrations ( a p5dulum1 resemble ! desc5t ( a body on an incl9$ plane1 & are produc$ by ! same cause2 n[ y mu/ recollect1 t ! great] ! p]p5dicul> height ( su* a plane1 9 proportion to its l5g?1 ! m rapid w be ! desc5t ( ! body2 a %ort p5dulum asc5ds to a great] height ?an a l>g] "o1 9 vibrat+ a giv5 di/ance1 & ( c\rse its desc5t mu/ be m rapid4 ,i %all n[1 ,i ?9k1 be able to expla9 to y ! cause ( ! v>iation ( ! seasons1 & ! diff]5ce 9 ! l5g? ( ! days & nights 9 ^? seasons2 bo? effects result+ f ! same cause4 ,9 mov+ r\nd ! sun1 ! axis ( ! e>? is n p]p5dicul> to ! plane ( its orbit4 ,suppos+ ?is r\nd table to repres5t ! plane ( ! e>?'s orbit1 & ?is little globe1 ! e>?2 ?r\gh ?is ,i h pass$ a wire1 repres5t+ its axis & poles4 ,9 mov+ r\nd ! table1 ,i d n hold ! wire p]p5dicul> to x1 b obliquely4 ,emily4 ,yes1 ,i und]/&1 ! e>? does n g r\nd ! sun 9 an upright position1 its axis is slant+ or oblique2 &1 x ( c\rse1 =ms an angle ) a l9e drawn p]p5dicul> to ! plane ( ! e>?'s orbit4 ,mrs4 ,b4 ,all ! l9es1 :i* y le>nt 9 y\r la/ lesson1 are del9eat$ on ?is little globe2 y mu/ consid] ! ecliptic z repres5t+ ! plane ( ! e>?'s orbit2 & ! equator1 :i* crosses ! ecliptic 9 two places1 !n %[s ! degree ( obliquity ( ! axis ( ! e>?2 :i* am\nts to #bc-a_/b degrees1 v ne>ly4 ,! po9ts 9 :i* ! ecliptic int]sects ! equator1 are call$ ! equ9octial po9ts4 ,b ,i believe ,i %all r5d] ! effects ( ! obliquity ( ! e>?'s axis cle>] to y1 by ! revolution ( ! little globe r\nd a c&le1 :i* %all repres5t ! sun4 7,plate ,,ix4 fig4 #b47 ,z ,i n[ hold x1 at ,a1 y see x 9 ! situation 9 :i* x is 9 ! mid/ ( summ]1 or :at is call$ ! summ] sol/ice1 :i* is on ! #ba/ ( ,june4 ,emily4 ,y hold ! wire awry1 ,i suppose1 9 ord] to %[ t ! axis ( ! e>? is n upright8 ,mrs4 ,b4 ,yes2 9 summ]1 ! nor? pole is incl9$ t[>ds ! sun4 ,9 ?is season1 !re=e1 ! nor!rn hemisph]e enjoys mu* m ( 8 rays ?an ! s\!rn4 ,! sun1 y see1 n[ %9es ov] ! :ole ( ! nor? frigid zone1 & not)/&+ ! e>?'s diurnal revolution1 :i* ,i imitate by twirl+ ! ball on ! wire1 x w cont9ue to %9e ^u x z long z x rema9s 9 ?is situation1 :il/ ! s\? frigid zone is at ! same "t completely 9 d>kness4 ,c>ol9e4 ,t is v /range2 ,i nev] be=e he>d t !re 0 con/ant day or night 9 any "p ( ! _w6 ,h[ mu* happi] ! inhabitants ( ! nor? frigid zone mu/ be ?an ^? ( ! s\!rn2 ! fir/ enjoy un9t]rupt$ day1 :ile ! la/ are involv$ 9 p]petual d>kness4 ,mrs4 ,b4 ,y judge ) too mu* precipitation2 exam9e a little fur!r1 & y w f9d1 t ! two frigid zones %>e an equal fate4 ,we %all n[ make ! e>? set (f f its position 9 ! summ] sol/ice1 & c>ry x r\nd ! sun2 obs]ve t ! pole is always incl9$ 9 ! same direction1 & po9ts to ! same spot 9 ! heav5s4 ,!re is a fix$ /> situat$ ne> t spot1 :i* is h5ce call$ ! nor? pol> />4 ,n[ let u /op ! e>? at ,b1 & exam9e x 9 its pres5t situation2 x has gone ?r\gh "o qu>t] ( its orbit1 & is arriv$ at t po9t at :i* ! ecliptic cuts1 or crosses1 ! equator1 & :i* is call$ ! autumnal equ9ox4 ,emily4 ,! sun n[ %9es f "o pole to ! o!r1 j z x w\ld con/antly d1 if ! axis ( ! e>? 7 p]p5dicul> to its orbit4 ,mrs4 ,b4 ,because ! incl9ation ( ! axis is n[ nei!r t[>ds ! sun1 nor 9 ! contr>y direction2 at ?is p]iod ( ! ye>1 ! days & nights are equal 9 e "p ( ! e>?4 ,b ! next /ep %e takes 9 h] orbit1 y see1 involves ! nor? pole 9 d>kness1 :il/ x illum9es t ( ! s\?2 ?is *ange 0 gradually prep>+ z ,i mov$ ! e>? f summ] to autumn2 ! arctic circle1 :i* 0 at fir/ entirely illum9$1 began to h %ort nights1 :i* increas$ z ! e>? approa*$ ! autumnal equ9ox2 & ! in/ant x pass$ t po9t1 ! long night ( ! nor? pole comm5ces1 & ! s\? pole beg9s to enjoy ! light ( ! sun4 ,we %all n[ make ! e>? proce$ 9 its orbit1 & y may obs]ve t z x advances1 ! days %ort5 & ! nights l5g!n1 ?r\gh\t ! nor!rn hemisph]e1 until x arrives at ! w9t] sol/ice1 on ! #ba/ ( ,decemb]1 :5 ! nor? frigid zone is entirely 9 d>kness1 & ! s\!rn has un9t]rupt$ daylight4 ,illu/ration3 ,,plate ,x4 ,c>ol9e4 ,!n1 aft] all1 ! sun :i* ,i ?\ght s p>tial1 conf]s 8 fav\rs equally on all4 ,mrs4 ,b4 ,n s ei!r3 ! inhabitants ( ! torrid zone h mu* m heat ?an we h1 z ! sun's rays fall p]p5dicul>ly twice 9 ! c\rse ( a ye>1 on e place )9 ! tropics1 :ile !y %9e m or less obliquely on ! re/ ( ! _w1 & almo/ horizontally at ! poles2 = dur+ _! long day ( six mon?s1 ! sun moves r\nd _! horizon )\t ei!r ris+ or sett+2 ! only obs]vable diff]5ce1 is t x is m elevat$ by a few degrees at mid-day1 ?an at midnight4 ,emily4 ,to a p]son plac$ 9 ! temp]ate zone1 9 ! situation 9 :i* we are 9 ,engl&1 ! sun w %9e nei!r s obliquely z x does on ! poles1 nor v]tically z at ! equator2 b its rays w fall ^u him m obliquely 9 autumn1 & w9t]1 ?an 9 summ]4 ,c>ol9e4 ,& !re=e1 ! inhabitants ( ! temp]ate zones1 w n h m]ely "o day1 & "o night1 9 ! ye>1 z happ5s at ! poles1 nor w !y h equal days1 & equal nights1 z at ! equator2 b _! days & nights w v>y 9 l5g?1 at diff]5t times ( ! ye>1 accord+ z _! respective poles incl9e t[>ds1 or f ! sun1 & ! diff]5ce w be great] 9 proportion to _! di/ance f ! equator4 ,mrs4 ,b4 ,we %all n[ foll[ ! e>? ?r\gh ! o!r half ( h] orbit1 & y w obs]ve1 t n[ exactly ! same *anges take place 9 ! s\!rn hemisph]e1 z ^? we h j rem>k$ 9 ! nor!rn4 ,day comm5ces at ! s\? pole1 :5 night sets 9 at ! nor? pole2 & 9 e o!r "p ( ! s\!rn hemisph]e ! days are long] ?an ! nights1 :ile1 on ! contr>y1 our nights are long] ?an our days4 ,:5 ! e>? arrives at ! v]nal equ9ox1 ,d1 :]e ! ecliptic aga9 cuts ! equator1 on ! #ba/ ( ,m>*1 %e is situat$1 ) respect to ! sun1 exactly 9 ! same position1 z 9 ! autumnal equ9ox2 & ! only diff]5ce ) respect to ! e>?1 is1 t x is n[ autumn 9 ! s\!rn hemisph]e1 :il/ x is spr+ ) u4 ,c>ol9e4 ,!n ! days & nights are aga9 e :]e equal4 ,mrs4 ,b4 ,yes1 = ! half ( ! globe :i* is enlight5$1 ext5ds exactly f "o pole to ! o!r1 ! sun has j ris5 to ! nor? pole1 & is j sett+ to ! s\? pole2 b 9 e o!r "p ( ! globe1 ! day & night is ( twelve h\rs l5g?2 h5ce ! ^w equ9ox1 :i* is d]iv$ f ! ,lat91 mean+ equal night4 ,z our summ] advances1 ! days l5g!n 9 ! nor!rn hemisph]e1 & %ort5 9 ! s\!rn1 till ! e>? rea*es ! summ] sol/ice1 :5 ! nor? frigid zone is entirely illum9$1 & ! s\!rn is 9 complete d>kness2 & we h n[ br\ght ! e>? aga9 to ! spot f :5ce we fir/ accompani$ h]4 ,emily4 ,?is is inde$ a mo/ satisfactory explanation ( ! cause ( ! diff]5t l5g?s ( our days & nights1 & ( ! v>iation ( ! seasons2 & ! m ,i le>n1 ! m ,i admire ! simplicity ( means by :i* su* wond]ful effects are produc$4 ,mrs4 ,b4 ,i "k n :i* is mo/ wor?y ( our admiration1 ! causes1 or ! effects ( ! e>?'s revolution r\nd ! sun4 ,! m9d c f9d no object ( contemplation m sublime1 ?an ! c\rse ( ?is magnific5t globe1 impell$ by ! comb9$ p[]s ( projection & attraction1 to roll 9 "o inv>iable c\rse1 ar\nd ! s\rce ( light & heat3 & :at c be m delightful ?an ! b5efic5t effects ( ?is vivify+ p[] on its att5dant planet4 ,x is at once ! gr& pr9ciple :i* animates & fecundates nature4 ,emily4 ,!re is "o circum/ance 9 :i* ?is little ivory globe appe>s to me to diff] f ! e>?2 x is n q d>k on t side ( x :i* is turn$ f ! c&le1 z is ! case ) ! e>? :5 nei!r moon nor />s are visible4 ,mrs4 ,b4 ,?is is ow+ to ! light ( ! c&le1 be+ reflect$ by ! walls ( ! room1 on e "p ( ! globe1 consequ5tly t side ( ! globe1 on :i* ! c&le does n directly %9e1 is n 9 total d>kness4 ,n[ ! skies h no walls to reflect ! sun's light on t side ( our e>? :i* is 9 d>kness4 ,c>ol9e4 ,i beg y\r p>don1 ,mrs4 ,b41 ,i ?9k t ! moon1 & />s1 answ] ! purpose ( walls 9 reflect+ ! sun's light to u 9 ! night4 ,mrs4 ,b4 ,v well1 ,c>ol9e2 t is to say1 ! moon & planets2 = ! fix$ />s1 y "k1 %9e by _! own light4 ,emily4 ,y say1 t ! sup]ior heat ( ! equatorial p>ts ( ! e>?1 arises f ! rays fall+ p]p5dicul>ly on ^? regions1 :il/ !y fall obliquely on ^! m nor!rn regions2 n[ ,i d n und]/& :y p]p5dicul> rays %\ld af=d m heat ?an oblique rays4 ,c>ol9e4 ,y ne$ only hold y\r h& p]p5dicul>ly ov] ! c&le1 & !n hold x sideways obliquely1 to be s5sible ( ! diff]5ce4 ,emily4 ,i d n d\bt ! fact1 b ,i wi% to h x expla9$4 ,mrs4 ,b4 ,y are q "r2 if ,c>ol9e _h n be5 satisfi$ ) asc]ta9+ ! fact1 )\t und]/&+ x1 %e w\ld n h br\ght =w>d ! c&le z an illu/ration2 ! reason :y y feel s mu* m heat if y hold y\r h& p]p5dicul>ly ov] ! c&le1 ?an if y hold x sideways1 is because a /ream ( heat$ vap\r con/antly asc5ds f ! c&le1 or any o!r burn+ body1 :i* be+ light] ?an ! air ( ! room1 does n spread lat]ally b rises p]p5dicul>ly1 & ?is l$ y to suppose t ! rays 7 hott] 9 ! latt] direction4 ,_h y reflect$1 y w\ld h discov]$ t rays issu+ f ! c&le sideways1 are no less p]p5dicul> to y\r h& :5 held opposite to !m1 ?an ! rays :i* asc5d :5 y\r h& is held ov] !m4 ,! reason :y ! sun's rays af=d less heat :5 9 an oblique direction1 ?an :5 p]p5dicul>1 is because few] ( !m fall ^u an equal portion ( ! e>?2 ?is w be und]/ood bett] by ref]r+ to plate #aj4 fig4 #a1 :i* repres5ts two equal portions ( ! sun's rays1 %9+ ^u diff]5t p>ts ( ! e>?4 ,"h x is evid5t1 t ! same quantity ( rays fall on ! space ,a ,b1 z fall on ! space ,b ,c2 & z ,a ,b is less ?an ,b ,c1 ! heat & light w be mu* /rong] 9 ! =m] ?an 9 ! latt]2 ,a ,b1 y see1 repres5ts ! equatorial regions1 :]e ! sun %9es p]p5dicul>ly2 & ,b ,c1 ! temp]ate & froz5 climates1 :]e 8 rays fall m obliquely4 ,emily4 ,?is acc\nts n only = ! great] heat ( ! equatorial regions1 b = ! great] heat ( our summ]s1 z ! sun %9es less obliquely 9 summ] ?an 9 w9t]4 ,mrs4 ,b4 ,?is y w see exemplifi$ 9 figure #b1 9 :i* ! e>? is repres5t$1 z x is situat$ on ! #ba/ ( ,june1 & ,engl& receives less oblique1 & consequ5tly a great] numb] ( rays1 ?an at any o!r season2 & figure #c1 %[s ! situation ( ,engl& on ! #ba/ ( ,decemb]1 :5 ! rays ( ! sun fall mo/ obliquely ^u h]4 ,b !re is also ano!r reason :y oblique rays give less heat1 ?an p]p5dicul> rays2 :i* is1 t !y h a great] portion ( ! atmosph]e to trav]se2 & ?\gh x is true1 t ! atmosph]e is itself a transp>5t body1 freely admitt+ ! passage ( ! sun's rays1 yet x is always load$ m or less ) d5se & foggy vap\r1 :i* ! rays ( ! sun _c easily p5etrate2 !re=e1 ! great] ! quantity ( atmosph]e ! sun's rays h to pass ?r\gh 9 _! way to ! e>?1 ! less heat !y w reta9 :5 !y rea* x4 ,?is w be bett] und]/ood1 by ref]r+ to fig4 #d4 ,! dott$ l9e r\nd ! e>?1 describes ! ext5t ( ! atmosph]e1 & ! l9es :i* proce$ f ! sun to ! e>?1 ! passage ( two equal portions ( ! sun's rays1 to ! equatorial & pol> regions2 ! latt] y see1 f its great] obliquity1 passes ?r\gh a great] ext5t ( atmosph]e4 ,c>ol9e4 ,& ?is1 no d\bt1 is ! reason :y ! sun1 9 ! morn+ & 9 ! ev5+1 gives s mu* less heat1 ?an at mid-day4 ,mrs4 ,b4 ,! dim9ution ( heat1 morn+ & ev5+1 is c]ta9ly ow+ to ! great] obliquity ( ! sun's rays2 & !y are also affect$ by ! o!r1 bo? ! cause1 :i* ,i h j expla9$ to y2 ! difficulty ( pass+ ?r\gh a foggy atmosph]e is p]haps m p>ticul>ly applicable to !m1 z mi/ & vap\rs are preval5t ab\t ! "t ( sunrise & sunset4 ,b ! dim9i%$ obliquity ( ! sun's rays1 is n ! sole cause ( ! heat ( summ]2 ! l5g? ( ! days greatly conduces to x2 = ! long] ! sun is above ! horizon1 ! m heat he w communicate to ! e>?4 ,c>ol9e4 ,bo? ! longe/ days1 & ! mo/ p]p5dicul> rays1 are on ! #ba/ ( ,june2 & yet ! greate/ heat prevails 9 ,july & ,augu/4 ,mrs4 ,b4 ,^? p>ts ( ! e>? :i* are once heat$1 reta9 ! heat = "s l5g? ( "t1 & ! additional heat !y receive1 occasions an elevation ( temp]ature1 al?\gh ! days beg9 to %ort51 & ! sun's rays to fall m obliquely4 ,= ! same reason1 we h g5]ally m heat at ?ree o'clock 9 ! aft]noon1 ?an at twelve1 :5 ! sun is on ! m]idian4 ,emily4 ,& pray1 h ! o!r planets ! same vicissitudes ( seasons1 z ! e>?8 ,mrs4 ,b4 ,"s ( !m m1 "s less1 accord+ z _! axes deviate m or less f ! p]p5dicul>1 to ! plane ( _! orbits4 ,! axis ( ,jupit]1 is ne>ly p]p5dicul> to ! plane ( 8 orbit2 ! axes ( ,m>s1 & ( ,saturn1 are ea*1 incl9$ at angles ( ab\t sixty degrees2 :il/ ! axis ( ,v5us is believ$ to be elevat$ only fifte5 or tw5ty degrees above h] orbit2 ! vicissitudes ( h] seasons mu/ !re=e be consid]ably great] ?an ours4 ,= fur!r p>ticul>s respect+ ! planets1 ,i %all ref] y to ,bonnyca/le's ,introduction to ,a/ronomy4 ,i h b "o m obs]vation to make to y1 relative to ! e>?'s motion2 :i* is1 t al?\gh we h b #cfe days & nights 9 ! ye>1 %e p]=ms #cff complete revolutions on h] axis1 dur+ t "t4 ,c>ol9e4 ,h[ is t possible8 = e complete revolution mu/ br+ ! same place back to ! sun4 ,x is n[ j twelve o'clock1 ! sun is1 !re=e1 on our m]idian2 9 tw5ty-f\r h\rs w x n h return$ to our m]idian aga91 & w n ! e>? h made a complete rotation on its axis8 ,mrs4 ,b4 ,if ! e>? _h no progressive motion 9 its orbit :il/ x revolves on its axis1 ?is w\ld be ! case2 b z x advances almo/ a degree we/w>d 9 its orbit1 9 ! same "t t x completes a revolution ea/w>d on its axis1 x mu/ revolve ne>ly "o degree m 9 ord] to br+ ! same m]idian back to ! sun4 ,c>ol9e4 ,oh1 yes6 x w require z mu* m ( a second revolution to br+ ! same m]idian back to ! sun1 z is equal to ! space ! e>? has advanc$ 9 h] orbit2 t is1 ne>ly a degree2 ?is diff]5ce is1 h[ev]1 v little4 ,mrs4 ,b4 ,^! small daily portions ( rotation1 are ea* equal to ! ?ree hundr$ & sixty-fif? "p ( a circle1 :i* at ! end ( ! ye> am\nts to "o complete rotation4 ,emily4 ,t is extremely curi\s4 ,if ! e>? !n1 _h no o!r ?an its diurnal motion1 we %\ld h #cff days 9 ! ye>4 ,mrs4 ,b4 ,we %\ld h #cff days 9 ! same p]iod ( "t t we n[ h #cfe2 b if we did n revolve r\nd ! sun1 we %\ld h no natural means ( comput+ ye>s4 ,y w be surpris$ to he>1 t if "t is calculat$ by ! />s in/ead ( ! sun1 ! irregul>ity :i* we h j notic$ does n occur1 & t "o complete rotation ( ! e>? on its axis1 br+s ! same m]idian back to any fix$ />4 ,emily4 ,t seems q unacc\ntable2 = ! e>? advances 9 h] orbit ) reg>d to ! fix$ />s1 ! same z ) reg>d to ! sun4 ,mrs4 ,b4 ,true1 b !n ! di/ance ( ! fix$ />s is s imm5se1 t our sol> sy/em is 9 comp>ison to x b a spot1 & ! :ole ext5t ( ! e>?'s orbit b a po9t2 !re=e1 :e!r ! e>? rema9 /ation>y1 or :e!r x revolv$ 9 its orbit dur+ its rotation on its axis1 no s5sible diff]5ce w\ld be produc$ ) reg>d to ! fix$ />s4 ,"o complete revolution br+s ! same m]idian back to ! same fix$ />2 h5ce ! fix$ />s appe> to g r\nd ! e>? 9 a %ort] "t ?an ! sun by ?ree m9utes fifty-six seconds ( "t4 ,c>ol9e4 ,^! ?ree m9utes fifty-six seconds is ! "t :i* ! e>? takes to p]=m ! additional ?ree hundr$ & sixty-fif? "p ( ! circle1 9 ord] to br+ ! same m]idian back to ! sun4 ,mrs4 ,b4 ,precisely4 ,h5ce ! />s ga9 e day ?ree m9utes fifty-six seconds on ! sun1 :i* makes !m rise t portion ( "t e>li] e day4 ,:5 "t is calculat$ by ! />s x is call$ sid]eal "t2 :5 by ! sun1 sol>1 or app>5t "t4 ,c>ol9e4 ,!n a sid]eal day is ?ree m9utes fifty-six seconds %ort]1 ?an a sol> day ( tw5ty-f\r h\rs4 ,mrs4 ,b4 ,i mu/ also expla9 to y :at is meant by a sid]eal ye>4 ,! common ye>1 call$ ! sol> or tropical ye>1 conta9+ #cfe days1 five h\rs1 =ty-eight m9utes & fifty-two seconds1 is measur$ f ! "t ! sun sets out f "o ( ! equ9oxes1 or sol/ices1 till x returns to ! same aga92 b ?is ye> is complet$1 be=e ! e>? has f9i%$ "o entire revolution 9 its orbit4 ,emily4 ,i ?\ght t ! e>? p]=m$ "o complete revolution 9 its orbit1 e ye>2 :at is ! reason ( ?is v>iation8 ,mrs4 ,b4 ,x is ow+ to ! sph]oidal figure ( ! e>?4 ,! elevation ab\t ! equator produces mu* ! same effect z if a simil> mass ( matt]1 collect$ 9 ! =m ( a moon1 revolv$ r\nd ! equator4 ,:5 ?is moon act$ on ! e>?1 9 conjunction )1 or 9 opposition to ! sun1 v>iations 9 ! e>?'s motion w\ld be occasion$1 & ^! v>iations produce :at is call$ ! precession ( ! equ9oxes4 ,illu/ration3 ,,plate ,,xi4 ,emily4 ,:at does t mean8 ,i ?\ght ! equ9octial po9ts1 7 fix$ po9ts 9 ! heav5s1 9 :i* ! equator cuts ! ecliptic4 ,mrs4 ,b4 ,^! po9ts are n q fix$1 b h an app>5tly retrograde motion1 among ! signs ( ! zodiac2 t is to say1 in/ead ( be+ at e revolution 9 ! same place1 !y move backw>ds4 ,?us if ! v]nal equ9ox is at ,a1 7fig4 #a4 plate ,,xi47 ! autumnal "o1 w be at ,b1 in/ead ( ,c1 & ! foll[+ v]nal equ9ox1 at ,d1 in/ead ( at ,a1 z w\ld be ! case if ! equ9oxes 7 /ation>y1 at opposite po9ts ( ! e>?'s orbit4 ,c>ol9e4 ,s t :5 ! e>? moves f "o equ9ox to ! o!r1 ?\gh x takes half a ye> to p]=m ! j\rney1 x has n travell$ ?r\gh half its orbit4 ,mrs4 ,b4 ,&1 consequ5tly1 :5 x returns aga9 to ! fir/ equ9ox1 x has n complet$ ! :ole ( its orbit4 ,9 ord] to asc]ta9 :5 ! e>? has p]=m$ an entire revolution 9 its orbit1 we mu/ obs]ve :5 ! sun returns 9 conjunction ) any fix$ />2 & ?is is call$ a sid]eal ye>4 ,suppos+ a fix$ /> situat$ at ,e1 7fig4 #a4 plate ,,xi47 ! sun w\ld n appe> 9 conjunction ) x1 till ! e>? _h return$ to ,a1 :5 x w\ld h complet$ its orbit4 ,emily4 ,& h[ mu* long] is ! sid]eal1 ?an ! sol> ye>8 ,mrs4 ,b4 ,only tw5ty m9utes2 s t ! v>iation ( ! equ9octial po9ts is v inconsid]able4 ,i h giv5 !m a great] ext5t 9 ! figure1 9 ord] to r5d] !m s5sible4 ,9 reg>d to "t1 ,i mu/ fur!r add1 t ! e>?'s diurnal motion on an incl9$ axis1 toge!r ) its annual revolution 9 an elliptic orbit1 occasions s mu* complication 9 its motion1 z to produce _m irregul>ities2 !re=e ! true "t _c be measur$ by ! app>5t place ( ! sun4 ,a p]fectly correct clock1 w\ld 9 "s p>ts ( ! ye> be be=e ! sun1 & 9 o!r p>ts aft] x4 ,!re are b f\r p]iods 9 :i* ! sun & a p]fect clock w\ld agree1 :i* is ! #ae? ( ,april1 ! #af? ( ,june1 ! #bc;d ( ,augu/1 & ! #bd? ( ,decemb]4 ,emily4 ,& is !re any consid]able diff]5ce betwe5 sol> "t1 & true "t8 ,mrs4 ,b4 ,! greate/ diff]5ce am\nts to betwe5 fifte5 & sixte5 m9utes4 ,tables ( equation are con/ruct$ = ! purpose ( po9t+ out1 & correct+ ^! diff]5ces betwe5 sol> "t & equal or mean "t1 :i* is ! d5om9ation giv5 by a/ronom]s1 to true "t4 ,que/ions #a4 7,pg4 #ib7 ,:at does ! l9e ,a ,b1 7fig4 #b plate #h47 repres5t1 & :at are its extremities call$8 #b4 7,pg4 #ib7 ,:at is meant by ! equator1 & h[ is x situat$8 #c4 7,pg4 #ib7 ,!re are two hemisph]es2 h[ are !y nam$ & di/+ui%$8 #d4 7,pg4 #ib7 ,:at are ! circles ne> ! poles call$8 #e4 7,pg4 #ib7 ,:at d ! l9es ,i ,k1 & ,l ,m1 repres5t8 #f4 7,pg4 #ib7 ,:at circle is 9 "p repres5t$ by ! l9e ,l ,k8 #g4 7,pg4 #ib7 ,aga9/ :at mi/ake mu/ y gu>d respect+ ?is l9e8 #h4 7,pg4 #ib7 ,:at is meant by a plane1 & h[ c\ld "o be repres5t$8 #i4 7,pg4 #ic7 ,describe :at is int5d$ by ! plane ( ! e>?'s orbit4 #aj4 7,pg4 #ic7 ,ext5d+ ?is plane to ! fix$ />s1 :at circle w\ld x =m1 & among :at p>ticul> />s w\ld x be f\nd8 #aa4 7,pg4 #ic7 ,:at is fig4 #a4 plate #i1 design$ to repres5t8 #ab4 7,pg4 #ic7 ,! ecliptic does n prop]ly belong to ! e>?1 = :at purpose !n is x describ$ on ! t]re/rial globe8 #ac4 7,pg4 #ic7 ,:at does ! obliquity ( ! ecliptic to ! equator s]ve to %[8 #ad4 7,pg4 #ic7 ,)9 :at limits d y f9d ! torrid zone8 #ae4 7,pg4 #ic7 ,:at two zones are !re betwe5 ! torrid1 & ! two frigid zones8 #af4 7,pg4 #ic7 ,:]e are ! frigid zones situat$8 #ag4 7,pg4 #ic7 ,:at is meant by ! t]m zone2 & are ! frigid zones prop]ly s call$8 #ah4 7,pg4 #ic7 ,h[ d m]idian l9es ext5d1 & :at is meant by ! m]idian ( a place8 #ai4 7,pg4 #ic7 ,:at is said ( ! m]idian to :i* ! sun is opposite1 & :]e is x !n midnight8 #bj4 7,pg4 #id7 ,:at h\r is x !n1 at places exactly half way betwe5 ^! m]idians8 #ba4 7,pg4 #id7 ,h[ are great] & less] circles di/+ui%$8 #bb4 7,pg4 #id7 ,:at "p ( a circle is a degree1 & h[ are ^! fur!r divid$8 #bc4 7,pg4 #id7 ,:at is ! diamet]1 & :at ! circumf]5ce ( a circle1 & :at proportion d !y be> to ea* o!r8 #bd4 7,pg4 #id7 ,:at "p ( a circle is a m]idian8 #be4 7,pg4 #id7 ,h[ _m degrees are !re betwe5 ! equator & ! poles8 #bf4 7,pg4 #id7 ,into :at p>ts1 besides degrees1 is ! ecliptic divid$8 #bg4 7,pg4 #id7 ,h[ are degrees ( latitude measur$1 & to :at numb] d !y ext5d8 #bh4 7,pg4 #id7 ,on :at circles are degrees ( longitude measur$1 & to :at numb] d !y ext5d8 #bi4 7,pg4 #id7 ,:at is a p>allel ( latitude8 #cj4 7,pg4 #ie7 ,degrees ( longitude v>y 9 l5g?2 :at is ! cause ( ?is8 #ca4 7,pg4 #ie7 ,:at is ! l5g? ( a degree ( latitude1 & :y d n ^! v>y8 #cb4 7,pg4 #ie7 ,:at causes ! equator to be some:at l>g] ?an a great circle pass+ ?r\gh ! poles1 & :at effect has ?is on degrees ( longitude measur$ on ! equator8 #cc4 7,pg4 #ie7 ,:at is ! cause ( ?is =m be+ giv5 to ! e>?8 #cd4 7,pg4 #if7 ,:at w\ld h be5 a consequ5ce ( ! c5trifugal =ce1 _h ! e>? be5 a p]fect sph]e8 #ce4 7,pg4 #if7 ,a body situat$ at ! poles1 is attract$ m =cibly ?an if plac$ at ! equator1 :at is ! reason8 #cf4 7,pg4 #ig7 ,:at effect w\ld be produc$ ^u ! gravity ( a body1 7 x plac$ b5ea? ! surface ( ! e>?1 & :at suppos+ x at its c5tre8 #cg4 7,pg4 #ig7 ,:at two circum/ances comb9e1 to less5 ! weight ( a body on ! equator8 #ch4 7,pg4 #ig7 ,:y c\ld n ?is be prov$ by weigh+ a body at ! poles1 & at ! equator8 #ci4 7,pg4 #ih7 ,:at is a p5dulum8 #dj4 7,pg4 #ih7 ,:at causes x to vibrate8 #da4 7,pg4 #ih7 ,:y are n its vibrations p]petual8 #db4 7,pg4 #ih7 ,two p5dulums ( ! same l5g?1 w n1 9 diff]5t latitudes1 p]=m _! vibrations 9 equal times1 :at is ! cause ( ?is8 #dc4 7,pg4 #ih7 ,to :at use has ?is prop]ty ( ! p5dulum be5 appli$8 #dd4 7,pg4 #ii7 ,:at *ange mu/ be made 9 p5dulums situat$ at ! equator & at ! poles1 to r5d] _! vibrations equal8 #de4 7,pg4 #ii7 ,:at d ! vibrations ( a p5dulum resemble1 & :y w x vibrate m rapidly if %ort5$8 #df4 7,pg4 #ii7 ,9 ! revolution ( ! e>? r\nd ! sun1 :at is ! position ( its axis8 #dg4 7,pg4 #ii7 ,h[ mu* is ! axis ( ! e>? incl9$1 & ) :at l9e does x =m ?is angle8 #dh4 7,pg4 #ii7 ,:at is repres5t$ by fig4 #b1 plate #i8 #di4 7,pg4 #ajj7 ,h[ is ! nor? pole incl9$ 9 ! middle ( our summ]1 & :at effect has ?is on ! nor? frigid zone8 #ej4 7,pg4 #ajj7 ,9 :at direction does ! nor? pole always po9t8 #ea4 7,pg4 #ajj7 ,:at is %[n by ! position ( ! e>? at ,b1 9 ! figure8 #eb4 7,pg4 #ajj7 ,h[ does ! sun !n %9e at ! poles1 & :at is ! effect on ! days & nights8 #ec4 7,pg4 #aja7 ,:5 ! e>? has pass$ ! autumnal equ9ox1 :at *anges take place at ! poles1 & also 9 ! :ole nor!rn & s\!rn hemisph]es8 #ed4 7,pg4 #aja7 ,:y is ! heat greate/ )9 ! torrid zone8 #ee4 7,pg4 #aja7 ,h[ does ! sun appe> at ! poles1 dur+ ! p]iod ( day !re8 #ef4 7,pg4 #aja7 ,9 :at w ! days & nights diff] 9 ! temp]ate zone1 f ^? at ! poles1 & at ! equator8 #eg4 7,pg4 #ajb7 ,trace ! e>? f ! w9t] sol/ice to ! v]nal equ9ox1 & in=m me :at *anges take place4 #eh4 7,pg4 #ajb7 ,:at takes place at ! "t ( ! v]nal equ9ox1 & :at is meant by ! t]m8 #ei4 7,pg4 #ajb7 ,9 proce$+ f ! v]nal equ9ox to ! summ] sol/ice1 :at *anges take place8 #fj4 7,pg4 #ajc7 ,f :at cause arises ! sup]ior heat ( ! equatorial regions8 #fa4 7,pg4 #ajc7 ,:y %\ld oblique rays af=d less heat ?an ^? :i* are p]p5dicul>8 #fb4 7,pg4 #ajc7 ,h[ is ?is expla9$ by fig4 #a4 plate #aj8 #fc4 7,pg4 #ajc7 ,h[ d y acc\nt = ! sup]ior heat ( summ]1 & h[ is ?is exemplifi$ 9 fig4 #b & #c1 plate #aj8 #fd4 7,pg4 #ajd7 ,:at o!r cause less5s ! int5sity ( oblique rays8 #fe4 7,pg4 #ajd7 ,h[ is ?is expla9$ by fig4 #d8 #ff4 7,pg4 #ajd7 ,:at causes conspire to less5 ! sol> heat 9 ! morn+ & ev5+8 #fg4 7,pg4 #ajd7 ,! greate/ heat ( summ] is aft] ! sol/ice1 & ! greate/ heat ( ! day1 aft] #ab o'clock1 al?\gh ! sun's rays are !n mo/ direct1 h[ is ?is acc\nt$ =8 #fh4 7,pg4 #aje7 ,is !re any *ange ( seasons 9 ! o!r planets8 #fi4 7,pg4 #aje7 ,:at is said respect+ ! axes ( ,jupit]1 ( ,m>s1 & ( ,saturn8 #gj4 7,pg4 #aje7 ,9 #cfe days1 h[ _m times does ! e>? revolve on its axis8 #ga4 7,pg4 #aje7 ,h[ is ?is acc\nt$ =8 #gb4 7,pg4 #aje7 ,d ! fix$ />s require ! same "t z ! sun1 to return to ! same m]idian8 #gc4 7,pg4 #ajf7 ,h[ is ?is acc\nt$ =8 #gd4 7,pg4 #ajf7 ,:at is meant by ! sol> & ! sid]eal day8 #ge4 7,pg4 #ajf7 ,:at is ! diff]5ce 9 "t betwe5 !m8 #gf4 7,pg4 #ajf7 ,:at is ! l5g? ( ! tropical ye>8 #gg4 7,pg4 #ajg7 ,! sol> ye> is complet$ be=e ! e>? has made a complete revolution 9 its orbit1 by :at is ?is caus$8 #gh4 7,pg4 #ajg7 ,:at is ?is call$1 & :at is repres5t$ respect+ x by fig4 #a1 plate #aa8 #gi4 7,pg4 #ajg7 ,by :at means c we asc]ta9 ! p]iod ( a complete revolution ( ! e>? 9 its orbit1 z illu/rat$ by ! fix$ /> ,e1 9 fig4 #a8 #hj4 7,pg4 #ajg7 ,:at diff]5ce is !re 9 ! l5g? ( ! sol> & sid]eal ye>8 #ha4 7,pg4 #ajg7 ,:y c we n always asc]ta9 ! true "t by ! app>5t place ( ! sun8 #hb4 7,pg4 #ajh7 ,:at w\ld be ! greate/ diff]5ce betwe5 sol>1 & true "t1 z indicat$ by a p]fect clock8 ,,conv]sation ,,ix4 ,,on ,,! ,,moon4 ,,( ,,! ,,moon',s ,,motion4 ,,phases ,,( ,,! ,,moon4 ,,eclipses ,,( ,,! ,,moon4 ,,eclipses ,,( ,,jupit]',s ,,moons4 ,,( ,,latitude ,,& ,,longitude4 ,,( ,,! ,,transits ,,( ,,! ,,inf]ior ,,planets4 ,,( ,,! ,,tides4 ,,mrs4 ,b4 ,we %all1 to-day1 conf9e our att5tion to ! moon1 :i* (f]s _m int]e/+ ph5om5a4 ,! moon revolves r\nd ! e>? 9 ! space ( ab\t tw5ty-n9e days & a half2 9 an orbit1 ! plane ( :i* is incl9$ upw>ds ( five degrees to t ( ! e>?2 %e accompanies u 9 our revolution r\nd ! sun4 ,emily4 ,h] motion !n mu/ be ( a complicat$ nature2 = z ! e>? is n /ation>y1 b advances 9 h] orbit1 :il/ ! moon goes r\nd h]1 ! moon1 9 pass+ r\nd ! sun1 mu/ proce$ 9 a sort ( scollop$ circle4 ,mrs4 ,b4 ,t is true2 & !re are also o!r circum/ances :i* int]f]e ) ! simplicity1 & regul>ity ( ! moon's motion1 b :i* are too intricate = y to und]/& at pres5t4 ,! moon always pres5ts ! same face to u1 by :i* x is evid5t t %e turns b once ^u h] axis1 :ile %e p]=ms a revolution r\nd ! e>?2 s t ! inhabitants ( ! moon h b "o day1 & "o night1 9 ! c\rse ( a lun> mon?4 ,c>ol9e4 ,we af=d !m1 h[ev]1 ! advantage ( a magnific5t moon to enlight5 _! long nights4 ,mrs4 ,b4 ,t advantage is put p>tial2 = s9ce we always see ! same hemisph]e ( ! moon1 ! inhabitants ( t hemisph]e alone1 c p]ceive u4 ,c>ol9e4 ,"o half ( ! moon !n enjoys our light1 :ile ! o!r half has con/antly nights ( d>kness4 ,if !re are any a/ronom]s 9 ^? regions1 !y w\ld d\btless be tempt$ to visit ! o!r hemisph]e1 9 ord] to behold s gr& a lum9>y z we mu/ appe> to !m4 ,b1 pray1 d !y see ! e>? "u all ! *anges1 :i* ! moon exhibits to u8 ,mrs4 ,b4 ,exactly s4 ,^! *anges are call$ ! phases ( ! moon1 & require "s explanation4 ,9 fig4 #b1 plate #aa1 let u say1 t ,s repres5ts ! sun1 ,e ! e>?1 & ,a ,b ,c ,d ,e ,f ,g ,h1 ! moon1 9 diff]5t p>ts ( h] orbit4 ,:5 ! moon is at ,a1 h] d>k side be+ turn$ t[>ds ! e>?1 we %all n see h] z at a2 b h] disappe>ance is ( v %ort duration1 & z %e advances 9 h] orbit1 we p]ceive h] "u ! =m ( a new moon3 :5 %e has gone ?r\gh "o eigh? ( h] orbit at ,b1 "o qu>t] ( h] enlight5$ hemisph]e w be turn$ t[>ds ! e>?1 & %e w !n appe> horn$ z at b2 :5 %e has p]=m$ "o qu>t] ( h] orbit1 %e %[s u "o half ( h] enlight5$ side1 z at c1 & ?is is call$ h] fir/ qu>t]2 at d %e is said to be gibb\s1 & at e ! :ole ( ! enlight5$ side appe>s to u1 & ! moon is at full4 ,z %e proce$s 9 h] orbit1 %e becomes aga9 gibb\s1 & h] enlight5$ hemisph]e turns gradually away f u1 until %e arrives at ,g1 :i* is h] ?ird qu>t]2 proce$+ !nce %e completes h] orbit & disappe>s1 & !n aga9 resumes h] =m ( a new moon1 & passes successively1 ?r\gh ! same *anges4 ,:5 ! moon is new1 %e is said to be 9 conjunction ) ! sun1 z !y are !n bo? 9 ! same direction f ! e>?2 at ! "t ( full moon1 %e is said to be 9 opposition1 because %e & ! sun1 are at opposite sides ( ! e>?2 at ! "t ( h] fir/ & ?ird qu>t]s1 %e is said to be 9 h] quadratures1 because %e is !n "o-f\r? ( a circle1 or #ij deg41 f h] conjunction1 or ! p]iod ( new moon4 ,emily4 ,are n ! eclipses ( ! sun produc$ by ! moon pass+ betwe5 ! sun & ! e>?8 ,mrs4 ,b4 ,yes2 :5 ! moon passes betwe5 ! sun & ! e>?1 %e int]cepts 8 rays1 or1 9 o!r words1 ca/s a %ad[ on ! e>?1 !n ! sun is eclips$1 & daylight gives place to d>kness1 :ile ! moon's %ad[ is pass+ ov] u4 ,:51 on ! contr>y1 ! e>? is betwe5 ! sun & ! moon1 x is we :o int]cept ! sun's rays1 & ca/ a %ad[ on ! moon2 %e is !n said to be eclips$1 & disappe>s f our view4 ,emily4 ,b z ! moon goes r\nd ! e>? e mon?1 %e mu/ be1 once dur+ t "t1 betwe5 ! e>? & ! sun2 & ! e>? mu/ likewise be once betwe5 ! sun & ! moon1 & yet we h n a sol> & a lun> eclipse e mon?8 ,mrs4 ,b4 ,i h already in=m$ y1 t ! orbits ( ! e>? & moon are n 9 ! same plane1 b cross or int]sect ea* o!r2 & ! moon g5]ally passes ei!r above or bel[ t ( ! e>?1 :5 %e is 9 conjunction ) ! sun1 & does n !re=e int]cept its rays1 & produce an eclipse2 = ?is c take place only :5 ! moon is 91 or ne> h] nodes1 :i* is ! "n giv5 to ^? two po9ts 9 :i* h] orbit crosses t ( ! e>?2 eclipses _c happ5 at any o!r "t1 because x is !n only1 t !y are bo? 9 a "r l9e ) ! sun4 ,emily4 ,& a p>tial eclipse ( ! moon takes place1 ,i suppose1 :51 9 pass+ by ! e>?1 %e is n suffici5tly above or bel[ ! %ad[1 to escape x entirely8 ,mrs4 ,b4 ,yes1 "o edge ( h] disk !n dips into ! %ad[1 & is eclips$2 b z ! e>? is l>g] ?an ! moon1 :5 eclipses happ5 precisely at ! nodes1 !y are n only total1 b la/ = upw>ds ( ?ree h\rs4 ,illu/ration3 ,,plate ,,xii4 ,a total eclipse ( ! sun r>ely occurs1 & :5 x happ5s1 ! total d>kness is conf9$ to "o p>ticul> "p ( ! e>?1 ! diamet] ( ! %ad[ n exce$+ #ahj miles2 evid5tly %[+ t ! moon is small] ?an ! sun1 s9ce %e _c entirely hide x f ! e>?4 ,9 fig4 #a1 plate #ab1 y w f9d a sol> eclipse describ$2 ,s is ! sun1 ,m ! moon1 & ,e ! e>?2 & ! moon's %ad[1 y see1 is n l>ge en\gh to cov] ! e>?4 ,! lun> eclipses1 on ! contr>y1 are visible f e "p ( ! e>?1 :]e ! moon is above ! horizon2 & we discov]1 by ! l5g? ( "t :i* ! moon is pass+ ?r\gh ! e>?'s %ad[1 t x w\ld be suffici5t to eclipse h] totally1 7 %e _m times h] actual size2 x foll[s1 !re=e1 t ! e>? is mu* l>g] ?an ! moon4 ,9 fig4 #b1 ,s repres5ts ! sun1 :i* p\rs =? rays ( light 9 /raight l9es1 9 e direction4 ,e is ! e>?1 & ,m ! moon4 ,n[ a ray ( light com+ f "o extremity ( ! sun's disk1 9 ! direction ,a ,b1 w meet ano!r1 com+ f ! opposite extremity1 9 ! direction ,c ,b2 ! %ad[ ( ! e>? _c !re=e ext5d beyond ,b2 z ! sun is l>g] ?an ! e>?1 ! %ad[ ( ! latt] is conical1 or 9 ! figure ( a sug> loaf2 x gradually dim9i%es1 & is mu* small] ?an ! e>? :]e ! moon passes ?r\gh x1 & yet we f9d ! moon to be1 n only totally eclips$1 b to rema9 = a consid]able l5g? ( "t 9 d>kness1 & h5ce we are enabl$ to asc]ta9 its real dim5sions4 ,emily4 ,:5 ! moon eclipses ! sun to u1 we mu/ be eclips$ to ! moon8 ,mrs4 ,b4 ,c]ta9ly2 = if ! moon int]cepts ! sun's rays1 & ca/s a %ad[ on u1 we mu/ necess>ily disappe> to ! moon1 b only p>tially1 z 9 fig4 #a4 ,c>ol9e4 ,!re mu/ be a great numb] ( eclipses 9 ! di/ant planets1 :i* h s _m moons8 ,mrs4 ,b4 ,yes1 few days pass )\t an eclipse tak+ place2 = among ! numb] ( satellites1 "o or ! o!r ( !m are cont9ually pass+ ei!r betwe5 _! prim>y & ! sun2 or betwe5 ! planet1 & ea* o!r4 ,a/ronom]s are s well acqua9t$ ) ! motion ( ! planets1 & _! satellites1 t !y h calculat$ n only ! eclipses ( our moon1 b ^? ( ,jupit]1 ) su* p]fect accuracy1 t x has af=d$ a means ( asc]ta9+ ! longitude4 ,c>ol9e4 ,b is x n v easy to f9d bo? ! latitude & longitude ( any place by a map or globe8 ,mrs4 ,b4 ,if y "k :]e y are situat$1 !re is no difficulty 9 asc]ta9+ ! latitude or longitude ( ! place1 by ref]r+ to a map2 b suppos+ t y _h be5 a l5g? ( "t at sea1 int]rupt$ 9 y\r c\rse by /orms1 a map w\ld af=d y v little assi/ance 9 discov]+ :]e y 74 ,c>ol9e4 ,"u su* circum/ances1 ,i confess ,i %\ld be equally at a loss to discov] ei!r latitude1 or longitude4 ,mrs4 ,b4 ,! latitude is usually f\nd by tak+ ! altitude ( ! sun at mid-day2 t is to say1 ! numb] ( degrees t x is elevat$ above ! horizon1 = ! sun appe>s m elevat$ z we approa* ! equator1 & less z we rec$e f x4 ,c>ol9e4 ,b unless y c see ! sun1 h[ c y take its altitude8 ,mrs4 ,b4 ,:5 x is too cl\dy to see ! sun1 ! latitude is sometimes f\nd at night1 by ! pol> />2 ! nor? pole ( ! e>?1 po9ts con/antly t[>ds "o p>ticul> "p ( ! heav5s1 9 :i* a /> is situat$1 call$ ! ,pol> />3 ?is /> is visible on cle> nights1 f e "p ( ! nor!rn hemisph]e2 ! altitude ( ! pol> />1 is !re=e ! same numb] ( degrees1 z t ( ! pole2 ! latitude may also be det]m9$ by obs]vations made on any ( ! fix$ />s3 ! situation !re=e ( a vessel at sea1 ) reg>d to nor? & s\?1 is easily asc]ta9$4 ,! difficulty is1 respect+ ea/ & we/1 t is to say1 its longitude4 ,z we h no ea/]n poles f :i* we c reckon our di/ance1 "s p>ticul> spot1 or l9e1 mu/ be fix$ ^u = t purpose4 ,! ,engli%1 reckon f ! m]idian ( ,gre5wi*1 :]e ! royal obs]vatory is situat$2 9 ,fr5* maps1 y w f9d t ! longitude is reckon$ f ! m]idian ( ,p>is4 ,! rotation ( ! e>? on its axis 9 #bd h\rs f we/ to ea/1 occasions1 y "k1 an app>5t motion ( ! sun & />s 9 a contr>y direction1 & ! sun appe>s to g r\nd ! e>? 9 ! space ( #bd h\rs1 pass+ ov] fifte5 degrees1 or a tw5ty-f\r? "p ( ! e>?'s circumf]5ce e h\r2 !re=e1 :5 x is twelve o'clock 9 ,london1 x is "o o'clock 9 any place situat$ fifte5 degrees to ! ea/ ( ,london1 z ! sun mu/ h pass$ ! m]idian ( t place1 an h\r be=e he rea*es t ( ,london4 ,= ! same reason x is elev5 o'clock 9 any place situat$ fifte5 degrees to ! we/ ( ,london1 z ! sun w n come to t m]idian till an h\r lat]4 ,if !n ! capta9 ( a vessel at sea1 c\ld "k precisely :at 0 ! h\r at ,london1 he c\ld1 by look+ at 8 wat*1 & comp>+ x ) ! h\r at ! spot 9 :i* he 01 asc]ta9 ! longitude4 ,emily4 ,b if he _h n alt]$ 8 wat*1 s9ce he sail$ f ,london1 x w\ld indicate ! h\r x !n 0 9 ,london4 ,mrs4 ,b4 ,true2 b 9 ord] to "k ! h\r ( ! day at ! spot 9 :i* he is1 ! capta9 ( a vessel regulates 8 wat* by ! sun :5 x rea*es ! m]idian4 ,emily4 ,!n if he _h two wat*es1 he might keep "o regulat$ daily1 & leave ! o!r unalt]$2 ! =m] w\ld indicate ! h\r ( ! place 9 :i* he 0 situat$1 & ! latt] ! h\r at ,london2 & by comp>+ !m toge!r1 he w\ld be able to calculate 8 longitude4 ,mrs4 ,b4 ,y h discov]$1 ,emily1 a mode ( f9d+ ! longitude1 :i* ,i h ! pleasure to tell y1 is univ]sally adopt$3 wat*es ( a sup]ior con/ruction1 call$ *ronomet]s1 or "t-keep]s1 are us$ = ?is purpose1 & are n[ made ) su* accuracy1 z n to v>y m ?an f\r or five seconds 9 a :ole ye>2 b ! be/ wat*es are liable to imp]fections1 & %\ld ! "t-keep] g too fa/ or too sl[1 !re w\ld be no means ( asc]ta9+ ! error2 implicit reliance1 _c consequ5tly be plac$ ^u !m4 ,rec\rse1 !re=e1 is sometimes _h to ! eclipses ( ,jupit]'s satellites4 ,a table is made1 ( ! precise "t at :i* ! sev]al moons are eclips$ to a spectator at ,london2 :5 !y appe> eclips$ to a spectator 9 any o!r spot1 he may1 by consult+ ! table1 "k :at is ! h\r at ,london2 = ! eclipse is visible at ! same mom5t1 f :atev] place on ! e>? x is se54 ,he has !n only to look at 8 wat*1 :i* he regulates by ! sun1 & :i* !re=e po9ts out ! h\r ( ! place 9 :i* he is1 & by obs]v+ ! diff]5ce ( "t !re1 & at ,london1 he may imm$iately det]m9e 8 longitude4 ,let u suppose1 t a c]ta9 moon ( ,jupit] is always eclips$ at six o'clock 9 ! ev5+2 & t a man at sea consults 8 wat*1 & f9ds t x is t5 o'clock at night1 :]e he is situat$1 at ! mom5t ! eclipse takes place1 :at w be 8 longitude8 ,emily4 ,t is f\r h\rs lat] ?an 9 ,london3 f\r times fifte5 degrees1 make #fj2 he w\ld1 !re=e1 be sixty degrees ea/ ( ,london1 = ! sun mu/ h pass$ 8 m]idian be=e x rea*es t ( ,london4 ,mrs4 ,b4 ,= ?is reason ! h\r is always lat] ?an 9 ,london1 :5 ! place is ea/ longitude1 & e>li] :5 x is we/ longitude4 ,?us ! longitude c be asc]ta9$ :5ev] ! eclipses ( ,jupit]'s moons are visible4 ,c>ol9e4 ,b d n ! prim>y planets1 sometimes eclipse ! sun f ea* o!r1 z !y pass r\nd 9 _! orbits8 ,mrs4 ,b4 ,!y mu/ ( c\rse sometimes pass betwe5 ea* o!r & ! sun1 b z _! %ad[s nev] rea* ea* o!r1 !y hide s little ( 8 light1 t ! t]m eclipse is n 9 ?is case us$2 ?is ph5om5on is call$ a transit4 ,! prim>y planets d n any ( !m revolve 9 ! same plane1 & ! times ( _! revolution r\nd ! sun is consid]able1 x !re=e b r>ely happ5s t !y are at ! same "t1 9 conjunction ) ! sun1 & 9 _! nodes4 ,x is evid5t also1 t a planet mu/ be inf]ior 7t is )9 ! orbit ( ano!r7 9 ord] to its app>5tly pass+ ov] ! disk ( ! sun4 ,m]cury1 & ,v5us1 h sometimes pass$ 9 a "r l9e betwe5 u1 & ! sun1 b be+ at s great a di/ance f u1 _! %ad[s did n ext5d s f> z ! e>?2 no d>kness 0 !re=e produc$ on any "p ( our globe2 b ! planet appe>$ l a small black spot1 pass+ across ! sun's disk4 ,x 0 by ! la/ transit ( ,v5us1 t a/ronom]s 7 enabl$ to calculate1 ) "s degree ( accuracy1 ! di/ance ( ! e>? f ! sun1 & ! dim5sions ( ! latt]4 ,emily4 ,i h he>d t ! tides are affect$ by ! moon1 b ,i _c conceive :at influ5ce x c h on !m4 ,mrs4 ,b4 ,!y are produc$ by ! moon's attraction1 :i* draws up ! wat]s ( t "p ( ! ocean ov] :i* ! moon passes1 s z to cause x to /& consid]ably high] ?an ! surr\nd+ p>ts4 ,c>ol9e4 ,does attraction act on wat] m p[]fully ?an on l&8 ,i %\ld h ?\ght x w\ld h be5 j ! contr>y1 = l& is c]ta9ly a m d5se body ?an wat]8 ,mrs ,b4 ,tides d n arise f wat] be+ m /rongly attract$ ?an l&1 = ?is c]ta9ly is n ! case2 b ! cohesion ( fluids1 be+ mu* less ?an t ( solid bodies1 !y m easily yield to ! p[] ( gravity2 9 consequ5ce ( :i*1 ! wat]s imm$iately bel[ ! moon1 are drawn up by x1 produc+ a full tide1 or :at is commonly call$1 high wat]1 at ! spot :]e x happ5s4 ,s f>1 ! !ory ( ! tides is n difficult to und]/&4 ,c>ol9e4 ,on ! contr>y1 no?+ c be m simple2 ! wat]s1 9 ord] to rise up "u ! moon1 mu/ draw ! wat]s f ! opposite side ( ! globe1 & occasion ebb-tide1 or l[ wat]1 9 ^? p>ts4 ,mrs4 ,b4 ,y draw y\r conclusion r too ha/ily1 my de>2 = accord+ to y\r !ory1 we %\ld h full tide only once 9 ab\t tw5ty-f\r h\rs1 t is1 e "t t we 7 bel[ ! moon1 :ile we f9d t 9 ?is "t we h two tides1 & t x is high wat] ) u1 & ) our antipodes1 at ! same "t4 ,c>ol9e4 ,yet x mu/ be impossible = ! moon to attract ! sea 9 opposite p>ts ( ! globe1 & 9 opposite directions1 at ! same "t4 ,mrs4 ,b4 ,?is opposite tide1 is r m difficult to expla91 ?an t :i* is imm$iately b5ea? ! moon2 ) a little att5tion1 h[ev]1 ,i hope ,i %all be able to make y und]/& ! explanation :i* has be5 giv5 ( x1 by a/ronom]s4 ,x mu/ be confess$1 h[ev]1 t ! !ory ^u ?is subject1 is att5d$ ) "s difficulties4 ,y recollect t ! e>? & ! moon mutually attract ea* o!r1 b d y suppose t e "p ( ! e>? is equally attract$ by ! moon8 ,emily4 ,c]ta9ly n2 y h taught u t ! =ce ( attraction decreases1 ) ! increase ( di/ance1 & !re=e t "p ( ! e>? :i* is f>!/ f ! moon1 mu/ be attract$ less p[]fully1 ?an t to :i* %e is ne>e/4 ,mrs4 ,b4 ,?is fact w aid u 9 ! explanation :i* ,i am ab\t to give to y4 ,9 ord] to r5d] ! "q m simple1 let u suppose ! e>? to be e :]e cov]$ by ! ocean1 z repres5t$ 9 7fig4 #c4 pl4 #ab47 ,m is ! moon1 ,a ,b ,c ,d ! e>?4 ,n[ ! wat]s on ! surface ( ! e>?1 ab\t ,a1 be+ m /rongly attract$ ?an any o!r "p1 w be elevat$3 ! attraction ( ! moon at ,b & ,c be+ less1 & at ,d lea/ ( all4 ,! high tide at ,a1 is acc\nt$ = f ! direct attraction ( ! moon2 to produce ?is ! wat]s are drawn f ,b & ,c1 :]e x w consequ5tly be l[ wat]4 ,at ,d1 ! attraction ( ! moon be+ consid]ably decreas$1 ! wat]s are left relatively high1 :i* height is increas$1 by ! c5trifugal =ce ( ! e>? be+ great] at ,d ?an at ,a1 9 consequ5ce ( its great] di/ance f ! common c5tre ( gravity ,x1 betwe5 ! e>? & ! moon4 ,emily4 ,! tide ,a1 !n1 is produc$ by ! moon's attraction1 & ! tide ,d1 is produc$ by ! c5trifugal =ce1 & increas$ by ! feebl5ess ( ! moon's attraction1 9 ^? p>ts4 ,c>ol9e4 ,& :5 x is high wat] at ,a & ,d1 x is l[ wat] at ,b & ,c3 n[ ,i ?9k ,i compreh5d ! nature ( ! tides1 ?\gh ,i confess x is n q s easy z ,i at fir/ ?\ght4 ,b1 ,mrs4 ,b41 :y does n ! sun produce tides1 z well z ! moon2 = its attraction is great] ?an t ( ! moon8 ,mrs4 ,b4 ,x w\ld be at an equal di/ance1 b our vic9ity to ! moon1 makes h] influ5ce m p[]ful4 ,! sun has1 h[ev]1 a consid]able effect on ! tides1 & increases or dim9i%es !m z x acts 9 conjunction )1 or 9 opposition to ! moon4 ,emily4 ,i d n q und]/& t4 ,mrs4 ,b4 ,! moon is a mon? 9 go+ r\nd ! e>?2 twice dur+ t "t1 !re=e1 at full & at *ange1 %e is 9 ! same direction z ! sun2 bo?1 !n act 9 conjunction on ! e>?1 & produce v great tides1 call$ spr+ tides1 z repres5t$ 9 fig4 #d1 at ,a & ,b2 b :5 ! moon is at ! int]m$iate p>ts ( h] orbit1 t is 9 h] quadratures1 ! sun1 in/ead ( af=d+ assi/ance1 weak5s h] p[]1 by act+ 9 opposition to x2 & small] tides are produc$1 call$ neap tides1 z repres5t$ at ,m1 9 fig4 #e4 ,emily4 ,i h (t5 obs]v$ ! diff]5ce ( ^! tides1 :5 ,i h be5 at ! sea side4 ,b s9ce attraction is mutual betwe5 ! moon & ! e>?1 we mu/ produce tides 9 ! moon2 & ^! mu/ be m consid]able 9 proportion z our planet is l>g]4 ,& yet ! moon does n appe> ( an oval =m4 ,mrs4 ,b4 ,y mu/ recollect1 t 9 ord] to r5d] ! explanation ( ! tides cle>]1 we suppose ! :ole surface ( ! e>? to be cov]$ ) ! ocean2 b t is n really ! case1 ei!r ) ! e>? or ! moon1 & ! l& :i* int]sects ! wat]1 de/roys ! regul>ity ( ! effect4 ,?us1 9 fl[+ up riv]s1 9 pass+ r\nd po9ts ( l&1 & into bays & inlets1 ! wat] is ob/ruct$1 & high wat] mu/ happ5 mu* lat]1 ?an w\ld o!rwise be ! case4 ,c>ol9e4 ,true2 we may1 h[ev]1 be c]ta9 t :5ev] x is high wat]1 ! moon is imm$iately ov] our heads4 ,mrs4 ,b4 ,n s ei!r2 = z a simil> effect is produc$ on t "p ( ! globe imm$iately b5ea? ! moon1 & on t "p mo/ di/ant f x1 x _c be ov] ! heads ( ! inhabitants ( bo? ^? situations1 at ! same "t4 ,besides1 z ! orbit ( ! moon is v ne>ly p>allel to t ( ! e>?1 %e is nev] v]tical1 b to ! inhabitants ( ! torrid zone4 ,c>ol9e4 ,9 ! torrid zone1 !n1 ,i hope y w grant t ! moon is imm$iately ov]1 or opposite ! spots :]e x is high wat]8 ,mrs4 ,b4 ,i _c ev5 admit t2 = ! ocean naturally p>tak+ ( ! e>?'s motion1 9 its rotation f we/ to ea/1 ! moon1 9 =m+ a tide1 has to cont5d aga9/ ! ea/]n motion ( ! waves4 ,all matt]1 y "k1 by its in]tia1 makes "s resi/ance to a *ange ( /ate2 ! wat]s1 !re=e1 d n readily yield to ! attraction ( ! moon1 & ! effect ( h] influ5ce is n complete1 till ?ree h\rs aft] %e has pass$ ! m]idian1 :]e x is full tide4 ,:5 a body is impell$ by any =ce1 its motion may cont9ue1 aft] ! impell+ =ce ceases to act3 ?is is ! case ) all projectiles4 ,a /one ?r[n f ! h&1 cont9ues its motion = a l5g? ( "t1 proportion$ to ! =ce giv5 to x3 !re is a p]fect analogy betwe5 ?is effect1 & ! cont9u$ rise ( ! wat]1 aft] ! moon has pass$ ! m]idian at any p>ticul> place4 ,emily4 ,pray :at is ! reason t ! tide is ?ree-qu>t]s ( an h\r lat] e day8 ,mrs4 ,b4 ,because x is tw5ty-f\r h\rs & ?ree-qu>t]s be=e ! same m]idian1 on our globe1 returns b5ea? ! moon4 ,! e>? revolves on its axis 9 ab\t tw5ty-f\r h\rs2 if ! moon 7 /ation>y1 !re=e1 ! same "p ( our globe w\ld1 e tw5ty-f\r h\rs1 return b5ea? ! moon2 b z dur+ our daily revolution1 ! moon advances 9 h] orbit1 ! e>? mu/ make m ?an a complete rotation1 9 ord] to br+ ! same m]idian opposite ! moon3 we are ?ree-qu>t]s ( an h\r 9 ov]tak+ h]4 ,! tides1 !re=e1 are ret>d$1 = ! same reason t ! moon rises lat] by ?ree-qu>t]s ( an h\r1 e day4 ,we h n[1 ,i ?9k1 conclud$ ! obs]vations ,i _h to make to y on ! subject ( a/ronomy2 at our next int]view1 ,i %all attempt to expla9 to y ! elem5ts ( hydro/atics4 ,que/ions #a4 7,pg4 #ajh7 ,9 :at "t does ! moon revolve r\nd ! e>?8 :at is ! incl9ation ( h] orbit8 & h[ does %e accompany ! e>?8 #b4 7,pg4 #ajh7 ,z ! moon revolves r\nd ! e>?1 & also accompanies x 9 its annual revolution1 9 :at =m w\ld y draw ! moon's orbit8 #c4 7,pg4 #aji7 ,:at causes ! moon always to pres5t ! same face to ! e>?1 & :at mu/ be ! l5g? ( a day & night to its inhabitants8 #d4 7,pg4 #aji7 ,c ! e>? be se5 f e "p ( ! moon1 & w x always exhibit ! same appe>ance8 #e4 7,pg4 #aji7 ,:at are ! *anges ( ! moon call$8 #f4 7,pg4 #aji7 ,h[ are ^! *anges expla9$ by fig4 #b4 plate #aa8 #g4 7,pg4 #aji7 ,:at is meant by h] fir/ qu>t]8 #h4 7,pg4 #aji7 ,:at by h] be+ horn$1 & h] be+ gibb\s8 #i4 7,pg4 #aji7 ,:at by h] be+ full8 #aj4 7,pg4 #aji7 ,:at by h] ?ird qu>t]8 #aa4 7,pg4 #aaj7 ,:at is meant by h] conjunction8--:at by h] be+ 9 opposition8--:at by h] quadratures8 #ab4 7,pg4 #aaj7 ,by :at are eclipses ( ! sun caus$8 #ac4 7,pg4 #aaj7 ,:at causes eclipses ( ! moon8 #ad4 7,pg4 #aaj7 ,:at is meant by ! moon's nodes8 #ae4 7,pg4 #aaj7 ,:y d n eclipses happ5 at e new & full moon8 #af4 7,pg4 #aaj7 ,:at causes p>tial eclipses ( ! moon8 #ag4 7,pg4 #aaj7 ,:5 ! moon is exactly 9 "o ( h] nodes1 :at l5g? ( "t w %e be eclips$8 #ah4 7,pg4 #aaj7 ,are total eclipses ( ! sun frequ5t1 & :5 !y happ5 :at is _! ext5t8 #ai4 7,pg4 #aaa7 ,:at does ?is prove respect+ ! size ( ! moon8 #bj4 7,pg4 #aaa7 ,:at is %[n 9 fig4 #a1 plate #ab8 #ba4 7,pg4 #aaa7 ,h[ are lun> eclipses visible1 & :at is prov$ by _! duration8 #bb4 7,pg4 #aaa7 ,:at is illu/rat$ by fig4 #b1 plate #ab8 #bc4 7,pg4 #aaa7 ,:at rem>k is made respect+ ^? planets :i* h sev]al moons8 #bd4 7,pg4 #aaa7 ,:at use is made ( ! eclipses ( ! satellites ( ,jupit]8 #be4 7,pg4 #aab7 ,h[ is ! latitude ( a place usually f\nd8 #bf4 7,pg4 #aab7 ,by :at o!r means may latitude be f\nd8 #bg4 7,pg4 #aab7 ,f :at is longitude reckon$8 #bh4 7,pg4 #aab7 ,h[ does ! rotation ( ! e>? ^u its axis1 gov]n ! "t at diff]5t places8 #bi4 7,pg4 #aac7 ,:at two circum/ances1 if kn[n1 w enable y to f9d y\r longitude f a giv5 place8 #cj4 7,pg4 #aac7 ,by :at means may a capta9 f9d ! "t at ,london1 & 9 ! place :]e 8 %ip may be8 #ca4 7,pg4 #aac7 ,h[ may ! eclipses ( ,jupit]'s satellites be us$ to f9d ! longitude8 #cb4 7,pg4 #aac7 ,give an example4 #cc4 7,pg4 #aad7 ,h[ w y "k :e!r ! longitude is ea/ or we/8 #cd4 7,pg4 #aad7 ,:at is meant by ! transit ( a planet8 #ce4 7,pg4 #aad7 ,:y c we see transits ( ,v5us & ,m]cury only8 #cf4 7,pg4 #aad7 ,by :at are tides caus$8 #cg4 7,pg4 #aad7 ,:y is n a simil> effect produc$ on ! l&8 #ch4 7,pg4 #aae7 ,9 :at two p>ts ( ! _w is x high wat] at ! same "t8 #ci4 7,pg4 #aae7 ,:at circum/ances respect+ ! decrease ( attraction are tak5 into acc\nt1 9 expla9+ ! tides8 #dj4 7,pg4 #aae7 ,h[ are ! high tides at ,a & ,d1 & ! l[ ones at ,b & ,c1 9 fig4 #c4 pl4 #ab1 acc\nt$ =8 #da4 7,pg4 #aaf7 ,has ! sun any influ5ce on ! tides1 & :y is x less ?an t ( ! moon8 #db4 7,pg4 #aaf7 ,:at is meant by spr+ tides1 & h[ are !y produc$8 #dc4 7,pg4 #aaf7 ,:at by neap tides1 & h[ are !y caus$8 #dd4 7,pg4 #aaf7 ,:at circum/ances affect ! "t ( ! tide 9 riv]s1 bays1 c48 #de4 7,pg4 #aag7 ,:y 9 ! op5 ocean1 is x high wat]1 "s h\rs aft] ! moon has pass$ ! m]idian8 #df4 7,pg4 #aag7 ,:y are ! tides ?ree-qu>t]s ( an h\r lat] e day8 ,,conv]sation ,x4 ,,on ,,! ,,me*anical ,,prop]ties ,,( ,,fluids4 ,,def9ition ,,( ,a ,,fluid4 ,,di/9ction ,,betwe5 ,,fluids ,,& ,,liquids4 ,,( ,,non-,,ela/ic ,,fluids4 ,,sc>cely ,,susceptible ,,( ,,compression4 ,,( ,,! ,,cohesion ,,( ,,fluids4 ,,( ,,_! ,,gravitation4 ,,( ,,_! ,,equilibrium4 ,,( ,,_! ,,pressure4 ,,( ,,specific ,,gravity4 ,,( ,,! ,,specific ,,gravity ,,( ,,bodies ,,heavi] ,,?an ,,wat]4 ,,( ,,^? ,,( ,,! ,,same ,,weight ,,z ,,wat]4 ,,( ,,^? ,,light] ,,?an ,,wat]4 ,,( ,,! ,,specific ,,gravity ,,( ,,fluids4 ,,mrs4 ,b4 ,we h hi!rto conf9$ our att5tion to ! me*anical prop]ties ( solid bodies1 :i* h be5 illu/rat$1 &1 ,i hope1 ?or\ghly impress$ ^u y\r memory1 by ! conv]sations we h subsequ5tly _h1 on a/ronomy4 ,x w n[ be necess>y = me to give y "s acc\nt ( ! me*anical prop]ties ( fluids--a sci5ce :i*1 :5 appli$ to liquids1 is divid$ into two p>ts1 hydro/atics & hydraulics4 ,hydro/atics1 treats ( ! weight & pressure ( fluids2 & hydraulics1 ( ! motion ( fluids1 & ! effects produc$ by ?is motion4 ,a fluid is a sub/ance :i* yields to ! slighte/ pressure4 ,if y dip y\r h& into a bas9 ( wat]1 y are sc>cely s5sible ( meet+ ) any resi/ance4 ,emily4 ,! attraction ( cohesion is !n1 ,i suppose1 less p[]ful 9 fluids1 ?an 9 solids8 ,mrs4 ,b4 ,yes2 fluids1 g5]ally speak+1 are bodies ( less d5sity ?an solids4 ,f ! slight cohesion1 ( ! p>ticles ( fluids1 & ! facility ) :i* !y slide ov] ea* o!r1 x is inf]r$1 t !y h b a slight attraction = ea* o!r1 & t ?is attraction is equal1 9 e position ( _! p>ticles1 & !re=e produces no resi/ance to a p]fect fre$om ( motion among !mselves4 ,c>ol9e4 ,pray :at is ! di/9ction betwe5 a fluid & a liquid8 ,mrs4 ,b4 ,liquids compreh5d only "o class ( fluids4 ,!re is ano!r class1 di/+ui%$ by ! "n ( ela/ic fluids1 or gases1 :i* compreh5ds ! air ( ! atmosph]e1 & all ! v>i\s k9ds ( air ) :i* y w become acqua9t$1 :5 y /udy *emi/ry4 ,_! me*anical prop]ties we %all exam9e h]eaft]1 & conf9e our att5tion ?is morn+1 to ^? ( liquids1 or non-ela/ic fluids4 ,wat]1 & liquids 9 g5]al1 are sc>cely susceptible ( be+ compress$1 or squeez$ into a small] space1 ?an t :i* !y naturally occupy4 ,su*1 h[ev]1 is ! extreme m9ut5ess ( _! p>ticles1 t by /rong compression1 !y sometimes =ce _! way ?r\gh ! pores ( ! sub/ance :i* conf9es !m4 ,?is 0 %[n by a celebrat$ exp]im5t1 made at ,flor5ce _m ye>s ago4 ,a holl[ globe ( gold 0 fill$ ) wat]1 & on its be+ submitt$ to great pressure1 ! wat] 0 se5 to exude ?r\gh ! pores ( ! gold1 :i* x cov]$ ) a f9e dew4 ,_m philosoph]s1 h[ev]1 ?9k t ?is exp]im5t is too mu* reli$ ^u1 z x does n appe> t x has ev] be5 repeat$2 x is possible1 !re=e1 t !re may h be5 "s s\rce ( error1 :i* 0 n discov]$ by ! exp]im5t]s4 ,fluids1 appe> to gravitate m freely1 ?an solid bodies2 = ! /rong cohesive attraction ( ! p>ticles ( ! latt]1 9 "s measure c\nt]acts ! effect ( gravity4 ,9 ?is table1 = in/ance1 ! cohesion ( ! p>ticles ( wood1 enables f\r sl5d] legs to support a consid]able weight4 ,7 ! cohesion de/roy$1 or1 9 o!r words1 ! wood conv]t$ into a fluid1 no support c\ld be af=d$ by ! legs1 = ! p>ticles no long] coh]+ toge!r1 ea* w\ld press sep>ately & indep5d5tly1 & w\ld be br\ght to a level ) ! surface ( ! e>?4 ,emily4 ,?is want ( cohesion is !n ! reason :y fluids c nev] be =m$ into figures1 or ma9ta9$ 9 heaps2 = ?\gh x is true ! w9d raises wat] into waves1 !y are imm$iately aft]w>ds de/roy$ by gravity1 & wat] always f9ds its level4 ,mrs4 ,b4 ,d y und]/& :at is meant by ! level1 or equilibrium ( fluids8 ,emily4 ,i believe ,i d1 ?\gh ,i feel r at a loss to expla9 x4 ,is n a fluid level :5 its surface is smoo? & flat1 z is ! case ) all fluids1 :5 9 a /ate ( re/8 ,mrs4 ,b4 ,smoo?1 if y please1 b n flat2 = ! def9ition ( ! equilibrium ( a fluid is1 t e "p ( ! surface is equally di/ant f ! po9t to :i* !y gravitate1 t is to say1 f ! c5tre ( ! e>?2 h5ce ! surface ( all fluids mu/ be sph]ical1 n flat1 s9ce !y w p>take ( ! sph]ical =m ( ! globe4 ,?is is v evid5t 9 l>ge bodies ( wat]1 su* z ! ocean1 b ! sph]icity ( small bodies ( wat]1 is s trifl+1 t _! surfaces appe> flat4 ,?is level1 or equilibrium ( fluids1 is ! natural result ( _! p>ticles gravitat+ indep5d5tly ( ea* o!r2 = :5 any p>ticle ( a fluid1 accid5tally f9ds itself elevat$ above ! re/1 x is attract$ d[n to ! level ( ! surface ( ! fluid1 & ! read9ess ) :i* fluids yield to ! slighte/ impression1 w enable ! p>ticle by its weight1 to p5etrate ! surface ( ! fluid1 & mix ) x4 ,c>ol9e4 ,b ,i h se5 a drop ( oil1 float on ! surface ( wat]1 )\t mix+ ) x4 ,mrs4 ,b4 ,!y d n mix1 because _! p>ticles repel ea* o!r1 & ! oil rises to ! surface1 because oil is a light] liquid ?an wat]4 ,if y 7 to p\r wat] ov] x1 ! oil w\ld /ill rise1 be+ =c$ up by ! sup]ior gravity ( ! wat]4 ,"h is an in/rum5t call$ a _s-level1 7fig4 #a1 plate #ac47 :i* is con/ruct$ ^u ! pr9ciple ( ! equilibrium ( fluids4 ,x consi/s ( a %ort tube ,a ,b1 clos$ at bo? ends1 & conta9+ a little wat]1 or m commonly "s spirits3 x is s ne>ly fill$1 z to leave only a small bubble ( air2 :5 ! tube is p]fectly horizontal1 ?is bubble w occupy ! middle ( x1 b :5 n p]fectly horizontal1 ! wat] runs to ! l[]1 & ! bubble ( air or _s rises to ! upp] end2 by ?is in/rum5t1 ! level ( any situation1 to :i* we apply x1 may be asc]ta9$4 ,f ! /rong cohesion ( _! p>ticles1 y may !re=e consid] solid bodies z gravitat+ 9 masses1 :ile e p>ticle ( a fluid may be consid]$ z sep>ate1 & gravitat+ indep5d5tly ( ea* o!r4 ,h5ce ! resi/ance ( a fluid1 is consid]ably less1 ?an t ( a solid body2 = ! resi/ance ( ! p>ticles1 act+ sep>ately1 is m easily ov]come4 ,emily4 ,a body ( wat]1 9 fall+1 does c]ta9ly less injury ?an a solid body ( ! same weight4 ,mrs4 ,b4 ,! p>ticles ( fluids1 act+ ?us indep5d5tly1 press aga9/ ea* o!r 9 e direction1 n only d[nw>ds1 b upw>ds1 & lat]ally or sideways2 & 9 consequ5ce ( ?is equality ( pressure1 e p>ticle rema9s at re/1 9 ! fluid4 ,if y agitate ! fluid1 y di/urb ?is equality ( pressure1 & ! fluid w n re/1 till its equilibrium is re/or$4 ,illu/ration3 ,,plate ,,xiii4 ,c>ol9e4 ,! pressure d[nw>ds is v natural2 x is ! effect ( gravity2 "o p>ticle1 weigh+ ^u ano!r1 presses on x2 b ! pressure sideways1 & p>ticul>ly ! pressure upw>ds1 ,i _c und]/&4 ,mrs4 ,b4 ,if !re 7 no lat]al pressure1 wat] w\ld n run out ( an op5+ on ! side ( a vessel4 ,if y fill a vessel ) s&1 x w n cont9ue to run out ( su* an op5+1 because !re is sc>cely any lat]al pressure among its p>ticles4 ,emily4 ,:5 wat] runs out ( ! side ( a vessel1 is x n ow+ to ! weight ( ! wat]1 above ! op5+8 ,mrs4 ,b4 ,if ! p>ticles ( fluids 7 arrang$ 9 regul> columns1 ?us1 7fig4 #b47 !re w\ld be no lat]al pressure1 = :5 "o p>ticle is p]p5dicul>ly above ! o!r1 x c only press d[nw>ds2 b z x mu/ cont9ually happ51 t a p>ticle presses betwe5 two p>ticles b5ea?1 7fig4 #c47 ^! la/1 mu/ suff] a lat]al pressure4 ,emily4 ,! same z :5 a w$ge is driv5 into a piece ( wood1 & sep>ates ! p>ts1 lat]ally4 ,mrs4 ,b4 ,yes4 ,! lat]al pressure proce$s1 !re=e1 entirely f ! pressure d[nw>ds1 or ! weight ( ! liquid above2 & consequ5tly1 ! l[] ! orifice is made 9 ! vessel1 ! great] w be ! velocity ( ! wat] ru%+ out ( x4 ,"h is a vessel ( wat] 7fig4 #e471 ) ?ree /op cocks at diff]5t heights2 we %all op5 !m1 & y w see ) :at diff]5t degrees ( velocity1 ! wat] issues f !m4 ,d y und]/& ?is1 ,c>ol9e8 ,c>ol9e4 ,oh yes4 ,! wat] f ! upp] sp\t1 receiv+ b a slight pressure1 on acc\nt ( its vic9ity to ! surface1 fl[s b g5tly2 ! second cock1 hav+ a great] weight above x1 ! wat] is =c$ out ) great] velocity1 :il/ ! l[e/ cock1 be+ ne> ! bottom ( ! vessel1 receives ! pressure ( almo/ ! :ole body ( wat]1 & ru%es out ) ! greate/ impetuosity4 ,mrs4 ,b4 ,v well2 & y mu/ obs]ve1 t z ! lat]al pressure1 is entirely ow+ to ! pressure d[nw>ds1 x is n affect$ by ! horizontal dim5sions ( ! vessel1 :i* conta9s ! wat]1 b m]ely by its dep?2 = z e p>ticle acts indep5d5tly ( ! re/1 x is only ! column ( p>ticles imm$iately above ! orifice1 t c weigh ^u1 & press out ! wat]4 ,emily4 ,! bread? & wid? ( ! vessel !n1 c be ( no consequ5ce 9 ?is respect4 ,! lat]al pressure on "o side1 9 a cubical vessel1 is1 ,i suppose1 n s great z ! pressure d[nw>ds ^u ! bottom4 ,mrs4 ,b4 ,no2 9 a cubical vessel1 ! pressure d[nw>ds w be d\ble ! lat]al pressure on "o side2 = e p>ticle at ! bottom ( ! vessel is press$ ^u1 by a column ( ! :ole dep? ( ! fluid1 :il/ ! lat]al pressure dim9i%es f ! bottom upw>ds to ! surface1 :]e ! p>ticles h no pressure4 ,c>ol9e4 ,& f :5ce proce$s ! pressure ( fluids upw>ds8 t seems to me ! mo/ unacc\ntable1 z x is 9 direct opposition to gravity4 ,mrs4 ,b4 ,& yet x is 9 consequ5ce ( _! pressure d[nw>ds4 ,:51 = example1 y p\r wat] into a tea-pot1 ! wat] rises 9 ! sp\t1 to a level ) ! wat] 9 ! pot4 ,! p>ticles ( wat] at ! bottom ( ! pot1 are press$ ^u by ! p>ticles above !m2 to ?is pressure !y w yield1 if !re is any mode ( mak+ way = ! sup]ior p>ticles1 & z !y _c desc5d1 !y w *ange _! direction1 & rise 9 ! sp\t4 ,suppose ! tea-pot to be fill$ ) columns ( p>ticles ( wat]1 simil> to t describ$ 9 fig4 #d41 ! p>ticle #a1 at ! bottom1 w be press$ lat]ally by ! p>ticle #b1 & by ?is pressure be =c$ into ! sp\t1 :]e1 meet+ ) ! p>ticle #c1 x presses x upw>ds1 & ?is pressure w be cont9u$ f #c to #d1 f #d to #e1 & s on1 till ! wat] 9 ! sp\t1 has ris5 to a level ) t 9 ! pot4 ,emily4 ,if x 7 n = ?is pressure upw>ds1 =c+ ! wat] to rise 9 ! sp\t1 ! equilibrium ( ! fluid w\ld be de/roy$4 ,c>ol9e4 ,true2 b !n a tea-pot is wide & l>ge1 & ! weight ( s great a body ( wat] z ! pot w conta91 may easily =ce up & support s small a quantity1 z w fill ! sp\t4 ,b w\ld ! same effect be produc$1 if ! sp\t & ! pot1 7 ( equal dim5sions8 ,mrs4 ,b4 ,und\bt$ly x w\ld4 ,y may ev5 rev]se ! exp]im5t1 by p\r+ wat] into ! sp\t1 & y w f9d t ! wat] w rise 9 ! pot1 to a level ) t 9 ! sp\t2 = ! pressure ( ! small quantity ( wat] 9 ! sp\t1 w =ce up & support1 ! l>g] quantity 9 ! pot4 ,9 ! pressure upw>ds1 z well z t lat]ally1 y see t ! =ce ( pressure1 dep5ds entirely on ! height1 & is q indep5d5t ( ! horizontal dim5sions ( ! fluid4 ,z a tea-pot is n transp>5t1 let u try ! exp]im5t by fill+ ?is l>ge glass goblet1 by means ( ?is n>r[ tube1 7fig4 #f47 ,c>ol9e4 ,look1 ,emily1 z ,mrs4 ,b4 fills x1 h[ ! wat] rises 9 ! goblet1 to ma9ta9 an equilibrium ) t 9 ! tube4 ,n[1 ,mrs4 ,b41 w y let me fill ! tube1 by p\r+ wat] into ! goblet8 ,mrs4 ,b4 ,t is impossible4 ,h[ev]1 y may try ! exp]im5t1 & ,i d\bt n t y w be able to acc\nt = its failure4 ,c>ol9e4 ,x is v s+ul>1 t if s small a column ( wat] z is conta9$ 9 ! tube1 c =ce up & support ! :ole cont5ts ( ! goblet2 t ! weight ( all ! wat] 9 ! goblet1 %\ld n be able to =ce up ! small quantity requir$ to fill ! tube3--oh1 ,i see n[ ! reason1 ! wat] 9 ! goblet1 _c =ce t 9 ! tube above its level1 & z ! end ( ! tube1 is consid]ably high] ?an ! goblet1 x c nev] be fill$ by p\r+ wat] into ! goblet4 ,mrs4 ,b4 ,& if y cont9ue to p\r wat] into ! goblet :5 x is full1 ! wat] w run ov]1 in/ead ( ris+ above its level 9 ! tube4 ,i %all n[ expla9 to y ! mean+ ( ! specific gravity ( bodies4 ,c>ol9e4 ,:at6 is !re ano!r species ( gravity1 ) :i* we are n yet acqua9t$8 ,mrs4 ,b4 ,no3 ! specific gravity ( a body1 means simply its weight1 comp>$ ) t ( ano!r body1 ( ! same size4 ,:5 we say1 t sub/ances1 su* z lead1 & /ones1 are heavy1 & t o!rs1 su* z pap] & fea!rs1 are light1 we speak comp>atively2 t is to say1 t ! fir/ are heavy1 & ! latt] light1 9 comp>ison ) ! g5]ality ( sub/ances 9 nature4 ,w\ld y call wood1 & *alk1 light or heavy bodies8 ,c>ol9e4 ,"s k9ds ( wood are heavy1 c]ta9ly1 z oak & mahogany2 o!rs are light1 z c$> & popl>4 ,emily4 ,i ?9k ,i %\ld call wood 9 g5]al1 a heavy body2 = c$> & popl>1 are light1 only 9 comp>ison to wood ( a heavi] description4 ,i am at a loss to det]m9e :e!r *alk %\ld be rank$ z a heavy1 or a light body2 ,i %\ld be incl9$ to say ! =m]1 if x 0 n t x is light] ?an mo/ o!r m9]als4 ,i p]ceive t we h b vague notions ( light & heavy4 ,i wi% !re 0 "s /&>d ( comp>ison1 to :i* we c\ld ref] ! weight ( all o!r bodies4 ,mrs4 ,b4 ,! necessity ( su* a /&>d1 has be5 s mu* felt1 t a body has be5 fix$ ^u = ?is purpose4 ,:at sub/ance d y ?9k w\ld be be/ calculat$ to answ] ?is end8 ,c>ol9e4 ,x mu/ be "o g5]ally kn[n1 & easily obta9$2 lead or iron1 = in/ance4 ,mrs4 ,b4 ,! metals1 w\ld n answ] ! purpose well1 = sev]al reasons2 !y are n always equally compact1 & !y are r>ely q pure2 two pieces ( iron1 = in/ance1 al?\gh ( ! same size1 might n1 f ! causes m5tion$1 weigh exactly alike4 ,c>ol9e4 ,b1 ,mrs4 ,b41 if y comp>e ! weight1 ( equal quantities ( diff]5t bodies1 !y w all be alike4 ,y "k ! old say+1 t a p\nd ( fea!rs1 is z heavy z a p\nd ( lead8 ,mrs4 ,b4 ,:5 !re=e we comp>e ! weight ( diff]5t k9ds ( bodies1 x w\ld be absurd to take quantities ( equal weight1 we mu/ take quantities ( equal bulk2 p9ts or qu>ts1 n ounces or p\nds4 ,c>ol9e4 ,v true2 ,i p]plex$ myself by ?9k+ t quantity ref]r$ to weight1 r ?an to measure4 ,x is true1 x w\ld be z absurd to comp>e bodies ( ! same size1 9 ord] to asc]ta9 :i* 0 l>ge/1 z to comp>e bodies ( ! same weight1 9 ord] to discov] :i* 0 heavie/4 ,mrs4 ,b4 ,9 e/imat+ ! specific gravity ( bodies1 !re=e1 we mu/ comp>e equal bulks1 & we %all f9d t _! specific gravity1 w be proportional to _! weights4 ,! body :i* has be5 adopt$ z a /&>d ( ref]5ce1 is di/ill$1 or ra9 wat]4 ,emily4 ,i am surpris$ t a fluid %\ld h be5 *os5 = ?is purpose1 z x mu/ necess>ily be conta9$ 9 "s vessel1 & ! weight ( ! vessel1 w require to be d$uct$4 ,mrs4 ,b4 ,y w f9d t ! comp>ison w be m easily made ) a fluid1 ?an ) a solid2 & wat] y "k c be e :]e obta9$4 ,9 ord] to le>n ! specific gravity ( a solid body1 x is n necess>y to put a c]ta9 measure ( x 9 "o scale1 & an equal measure ( wat] into ! o!r scale3 b simply to weigh ! body "u trial1 fir/ 9 air1 & !n 9 wat]4 ,if y weigh a piece ( gold1 9 a glass ( wat]1 w n ! gold displace j z mu* wat]1 z is equal to its own bulk8 ,c>ol9e4 ,c]ta9ly1 :]e "o body is1 ano!r _c be at ! same "t2 s t a suffici5t quantity ( wat] mu/ be remov$1 9 ord] to make way = ! gold4 ,mrs4 ,b4 ,yes1 a cubic in* ( wat]1 to make room = a cubic in* ( gold2 rememb] t ! bulk1 alone1 is to be consid]$2 ! weight1 has no?+ to d ) ! quantity ( wat] displac$1 = an in* ( gold1 does n occupy m space1 & !re=e w n displace m wat]1 ?an an in* ( ivory1 or any o!r sub/ance1 t w s9k 9 wat]4 ,well1 y w p]haps be surpris$ to he> t ! gold w weigh less 9 wat]1 ?an x did out ( x8 ,emily4 ,& = :at reason8 ,mrs4 ,b4 ,on acc\nt ( ! upw>d pressure ( ! p>ticles ( wat]1 :i* 9 "s measure supports ! gold1 & by s do+1 dim9i%es its weight4 ,if ! body imm]s$ 9 wat]1 0 ( ! same weight z t fluid1 x w\ld be :olly support$ by x1 j z ! wat] :i* x displaces1 0 support$1 previ\s to its mak+ way = ! solid body4 ,if ! body is heavi] ?an ! wat]1 x _c be :olly support$ by x2 b ! wat] w (f] "s resi/ance to its desc5t4 ,c>ol9e4 ,& ! resi/ance :i* wat] (f]s to ! desc5t ( heavy bodies imm]s$ 9 x1 7s9ce x proce$s f ! upw>d pressure ( ! p>ticles ( ! fluid17 mu/ 9 all cases1 ,i suppose1 be ! same8 ,mrs4 ,b4 ,yes3 ! resi/ance ( ! fluid1 is proportion$ to ! bulk1 & n to ! weight1 ( ! body imm]s$ 9 x2 all bodies ( ! same size1 !re=e1 lose ! same quantity ( _! weight 9 wat]4 ,c y =m any idea :at ?is loss w be8 ,emily4 ,i %\ld ?9k x w\ld be equal to ! weight ( ! wat] displac$2 =1 s9ce t portion ( ! wat] 0 support$ be=e ! imm]sion ( ! solid body1 an equal weight ( ! solid body1 w be support$4 ,mrs4 ,b4 ,y are p]fectly "r2 a body weigh$ 9 wat]1 loses j z mu* ( its weight1 z is equal to t ( ! wat] x displaces2 s t if y 7 to put ! wat] displac$1 into ! scale to :i* ! body is susp5d$1 x w\ld re/ore ! balance4 ,y mu/ obs]ve1 t :5 y weigh a body 9 wat]1 9 ord] to asc]ta9 its specific gravity1 y mu/ n s9k ! di% ( ! balance 9 ! wat]2 b ei!r susp5d ! body to a hook at ! bottom ( ! di%1 or else take (f ! di%1 & susp5d to ! arm ( ! balance a weight to c\nt]balance ! o!r di%1 & to ?is atta* ! solid to be weigh$1 7fig4 #g47 ,n[ suppose t a cubic in* ( gold1 weigh$ #ai ounces out ( wat]1 & lo/ "o ounce ( its weight by be+ weigh$ 9 wat]1 :at w\ld be its specific gravity8 ,c>ol9e4 ,! cubic in* ( wat] x displac$1 mu/ weigh t "o ounce2 & z a cubic in* ( gold1 weighs #ai ounces1 gold is #ai times1 z heavy z wat]4 ,emily4 ,i recollect hav+ se5 a table ( ! comp>ative weights ( bodies1 9 :i* gold appe>$ to me to be e/imat$ at #ai ?\s& times1 ! weight ( wat]4 ,mrs4 ,b4 ,y misund]/ood ! mean+ ( ! table4 ,9 ! e/imation y allude to1 ! weight ( wat] 0 reckon$ at #ajjj4 ,y mu/ obs]ve1 t ! weight ( a sub/ance :5 n comp>$ to t ( any o!r1 is p]fectly arbitr>y2 & :5 wat] is adopt$ z a /&>d1 we may d5om9ate its weight by any numb] we please2 b !n ! weight ( all bodies tri$ by ?is /&>d1 mu/ be signifi$ by proportional numb]s4 ,c>ol9e4 ,we may call ! weight ( wat]1 = example1 "o1 & !n t ( gold1 w\ld be n9ete52 or if we *oose to call ! weight ( wat] #ajjj1 t ( gold w\ld be #ai1jjj4 ,9 %ort1 specific gravity1 means h[ _m times m a body weighs1 ?an an equal bulk ( wat]4 ,mrs4 ,b4 ,x is r ! weight ( a body comp>$ ) a portion ( wat] equal to x 9 bulk2 = ! specific gravity ( _m sub/ances1 is less ?an t ( wat]4 ,c>ol9e4 ,!n y _c asc]ta9 ! specific gravity ( su* sub/ances1 9 ! same mann] z t ( gold2 = a body t is light] ?an wat]1 w float on its surface1 )\t displac+ any ( x4 ,mrs4 ,b4 ,if a body 7 absolutely )\t weight1 x is true t x w\ld n displace a drop ( wat]1 b ! bodies we are treat+ (1 h all "s weight1 h[ev] small2 & w1 !re=e1 displace "s quantity4 ,if ! body be light] ?an wat]1 x w n s9k to a level ) its surface1 & !re=e x w n displace s mu* wat] z is equal to its bulk2 b only s mu*1 z is equal to its weight4 ,a %ip1 y mu/ h obs]v$1 s9ks to "s dep? 9 wat]1 & ! heavi] x is lad51 ! deep] x s9ks1 z x always displaces a quantity ( wat]1 equal to its own weight4 ,c>ol9e4 ,b y said j n[1 t 9 ! imm]sion ( gold1 ! bulk1 & n ! weight ( body1 0 to be consid]$4 ,mrs4 ,b4 ,t is ! case ) all sub/ances :i* are heavi] ?an wat]2 b s9ce ^? :i* are light]1 d n displace s mu* z _! own bulk1 ! quantity !y displace is n a te/ ( _! specific gravity4 ,9 ord] to obta9 ! specific gravity ( a body :i* is light] ?an wat]1 y mu/ atta* to x a heavy "o1 ^: specific gravity is kn[n1 & imm]se !m toge!r2 ! specific gravity ( ! light] body1 may !n be easily calculat$ f obs]v+ ! loss ( weight x produces1 9 ! heavy body4 ,emily4 ,b are !re n "s bodies :i* h exactly ! same specific gravity z wat]8 ,mrs4 ,b4 ,und\bt$ly2 & su* bodies w rema9 at re/ 9 :atev] situation !y are plac$ 9 wat]4 ,"h is a piece ( wood :i* ,i h procur$1 because x is ( a k9d :i* is precisely ! weight ( an equal bulk ( wat]2 9 :atev] "p ( ?is vessel ( wat] y place x1 y w f9d t x w rema9 /ation>y4 ,c>ol9e4 ,i %all fir/ put x at ! bottom2 f !nce1 ( c\rse1 x _c rise1 because x is n light] ?an wat]4 ,n[ ,i %all place x 9 ! middle ( ! vessel2 x nei!r rises nor s9ks1 because x is nei!r light] nor heavi] ?an ! wat]4 ,n[ ,i w lay x on ! surface ( ! wat]2 b !re x s9ks a little--:at is ! reason ( t1 ,mrs4 ,b48 ,mrs4 ,b4 ,s9ce x is n light] ?an ! wat]1 x _c float ^u its surface2 s9ce x is n heavi] ?an wat]1 x _c s9k bel[ its surface3 x w s9k !re=e1 only till ! upp] surface ( bo? bodies are on a level1 s t ! piece ( wood is j cov]$ ) wat]4 ,if y p\r$ a few drops ( wat] into ! vessel1 7s g5tly z n to give !m mom5tum7 !y w\ld mix ) ! wat] at ! surface1 & n s9k l[]4 ,c>ol9e4 ,i n[ und]/& ! reason1 :y1 9 draw+ up a bucket ( wat] out ( a well1 ! bucket feels s mu* heavi] :5 x rises above ! surface ( ! wat] 9 ! well2 = :il/ y raise x 9 ! wat]1 ! wat] )9 ! bucket be+ ( ! same specific gravity z ! wat] on ! outside1 w be :olly support$ by ! upw>d pressure ( ! wat] b5ea? ! bucket1 & consequ5tly v little =ce w be requir$ to raise x2 b z soon z ! bucket rises to ! surface ( ! well1 y imm$iately p]ceive ! increase ( weight4 ,emily4 ,& h[ d y asc]ta9 ! specific gravity ( fluids8 ,mrs4 ,b4 ,by means ( an hydromet]2 ?is in/rum5t is made ( v>i\s mat]ials1 & 9 diff]5t =ms1 "o ( :i* ,i w %[ y4 ,x consi/s ( a ?9 brass ball ,a1 7fig4 #h1 plate #ac47 ) a graduat$ tube ,b1 & ! specific gravity ( ! liquid1 is e/imat$ by ! dep? to :i* ! in/rum5t s9ks 9 x1 or by ! weight requir$ to s9k x to a giv5 dep?4 ,!re is a small bucket ,c1 susp5d$ at ! l[] end1 & also a little di% on ! graduat$ tube2 into ei!r ( ^!1 small weights may be put1 until ! in/rum5t s9ks 9 ! fluid1 to a m>k on ! tube ,b2 ! am\nt ( weight necess>y = ?is1 w enable y to discov] ! specific gravity ( ! fluid4 ,i mu/ n[ take leave ( y2 b !re rema9 yet _m obs]vations to be made on fluids3 we %all1 !re=e1 resume ?is subject at our next int]view4 ,que/ions #a4 7,pg4 #aah7 ,:at are ! two divisions ( ! sci5ce :i* treats ( ! me*anical prop]ties ( liquids8 #b4 7,pg4 #aah7 ,( :at d hydro/atics & hydraulics treat8 #c4 7,pg4 #aah7 ,:at is a fluid def9$ to be8 #d4 7,pg4 #aah7 ,f :at is fluidity suppos$ to arise8 #e4 7,pg4 #aah7 ,into :at two classes are fluids divid$8 #f4 7,pg4 #aai7 ,:at is said ( ! incompressibility ( liquids1 & :at exp]im5t is relat$8 #g4 7,pg4 #aai7 ,ought ?is exp]im5t to be consid]$ z conclusive8 #h4 7,pg4 #aai7 ,:y d fluids appe> to gravitate m freely ?an solids8 #i4 7,pg4 #abj7 ,:5 is a fluid said to be 9 equilibrium8 #aj4 7,pg4 #abj7 ,:at is !re 9 ! nature ( a fluid1 :i* causes x to seek ?is level8 #aa4 7,pg4 #abj7 ,:at circum/ances occasion oil to float ^u wat]8 #ab4 7,pg4 #abj7 ,:at is ! nature & use ( ! in/rum5t repres5t$ 9 fig4 #a1 plate #ac8 #ac4 7,pg4 #abj7 ,:at diff]5ce is !re 9 ! gravitation ( solid masses1 & ( fluids8 #ad4 7,pg4 #aba7 ,:at results z reg>ds ! pressure ( fluids8 #ae4 7,pg4 #aba7 ,h[ is ?is illu/rat$ by fig4 #b1 #c1 plate #ac8 #af4 7,pg4 #aba7 ,f :at does ! lat]al pressure proce$8 & to :at is x proportion$1 z exemplifi$ 9 fig4 #e1 plate #ac8 #ag4 7,pg4 #abb7 ,has ! ext5t ( ! surface ( a fluid1 any effect ^u its pressure d[nw>ds8 #ah4 7,pg4 #abb7 ,:at w be ! diff]5ce betwe5 ! pressure ^u ! bottom1 & ^u "o side ( a cubical vessel8 #ai4 7,pg4 #abb7 ,:at occasions ! upw>d pressure1 & h[ is x expla9$ by fig4 #d1 plate #ac8 #bj4 7,pg4 #abc7 ,h[ c\ld ! equilibrium ( fluids be exemplifi$ by p\r+ wat] 9 at ! sp\t ( a tea-pot8 #ba4 7,pg4 #abc7 ,h[ by ! app>atus repres5t$ at fig4 #f1 plate #ac8 #bb4 7,pg4 #abc7 ,:at is meant by ! specific gravity ( a body8 #bc4 7,pg4 #abc7 ,:at d we 9 common mean by call+ a body heavy1 or light8 #bd4 7,pg4 #abd7 ,:y w\ld n ! metals answ] to comp>e o!r bodies )8 #be4 7,pg4 #abd7 ,:at mu/ be suppos$ equal 9 e/imat+ ! specific gravity ( a body8 #bf4 7,pg4 #abd7 ,:at has be5 adopt$ z a /&>d = comp>ison8 #bg4 7,pg4 #abe7 ,:at is ! fir/ /ep 9 asc]ta9+ ! specific gravity ( a solid8 #bh4 7,pg4 #abe7 ,:at quantity ( wat] w ! solid displace8 #bi4 7,pg4 #abe7 ,:y w a solid weigh less 9 wat] ?an 9 air1 & to :at w ! loss ( weight be equal8 #cj4 7,pg4 #abf7 ,:at is ! arrangem5t repres5t$ by fig4 #g1 plate #ac8 #ca4 7,pg4 #abf7 ,:at is /at$ ( gold z an example8 #cb4 7,pg4 #abf7 ,9 comp>+ a body ) wat]1 ?is is sometimes call$ #ajjj1 :at mu/ be obs]v$8 #cc4 7,pg4 #abf7 ,:at quantity ( wat] is displac$1 by a body float+ ^u its surface8 #cd4 7,pg4 #abg7 ,h[ c y f9d ! specific gravity ( a solid :i* is light] ?an wat]8 #ce4 7,pg4 #abg7 ,:at is obs]v$ ( a body ^: specific gravity is ! same z t ( wat]8 #cf4 7,pg4 #abg7 ,:at is ! reason t 9 draw+ a bucket ( wat] f a well1 its weight is n p]ceiv$ until x rises above ! surface8 #cg4 7,pg4 #abh7 ,describe ! in/rum5t repres5t$ by fig4 #h1 plate #ac1 & also h[1 & = :at x is us$8 ,,conv]sation ,,xi4 ,,( ,,spr+s1 ,,f\nta9s1 c4 ,,( ,,! ,,asc5t ,,( ,,vap\r ,,& ,,! ,,=mation ,,( ,,cl\ds4 ,,( ,,! ,,=mation ,,& ,,fall ,,( ,,ra91 c4 ,,( ,,! ,,=mation ,,( ,,spr+s4 ,,( ,,riv]s ,,& ,,lakes4 ,,( ,,f\nta9s4 ,,c>ol9e4 ,!re is a "q ,i am v desir\s ( ask+ y1 respect+ fluids1 ,mrs4 ,b41 :i* has (t5 p]plex$ me4 ,:at is ! reason t ! great quantity ( ra9 :i* falls ^u ! e>? & s9ks into x1 does n1 9 ! c\rse ( "t1 injure its solidity8 ,! sun & ! w9d1 ,i "k1 dry ! surface1 b !y h no effect on ! int]ior p>ts1 :]e !re mu/ be a prodigi\s accumulation ( moi/ure4 ,mrs4 ,b4 ,d y n "k1 t1 9 ! c\rse ( "t1 all ! wat] :i* s9ks into ! gr\nd1 rises out ( x aga98 ,x is ! same wat] :i* successively =ms seas1 riv]s1 spr+s1 cl\ds1 ra91 & sometimes hail1 sn[ & ice4 ,if y w take ! tr\ble ( foll[+ x ?r\gh ^! v>i\s *anges1 y w und]/& :y ! e>? is n yet dr[n$1 by ! quantity ( wat] :i* has fall5 ^u x1 s9ce its creation2 & y w ev5 be conv9c$1 t x does n conta9 a s+le drop m wat] n[1 ?an x did at t p]iod4 ,let u consid] h[ ! cl\ds 7 orig9ally =m$4 ,:5 ! fir/ rays ( ! sun w>m$ ! surface ( ! e>?1 ! heat1 by sep>at+ ! p>ticles ( wat]1 r5d]$ !m light] ?an ! air4 ,?is1 y "k1 is ! case ) /eam or vap\r4 ,:at !n ensues8 ,c>ol9e4 ,:5 light] ?an ! air1 x w naturally rise2 & n[ ,i recollect y\r tell+ u 9 a prec$+ lesson1 t ! heat ( ! sun trans=m$ ! p>ticles ( wat] into vap\r2 9 consequ5ce ( :i*1 x asc5d$ into ! atmosph]e1 :]e x =m$ cl\ds4 ,mrs4 ,b4 ,we h !n already foll[$ wat] ?r\gh two ( its trans=mations2 f wat] x becomes vap\r1 & f vap\r cl\ds4 ,emily4 ,b s9ce ?is wat]y vap\r is light] ?an ! air1 :y does x n cont9ue to rise2 & :y does x unite aga91 to =m cl\ds8 ,mrs4 ,b4 ,because ! atmosph]e dim9i%es 9 d5sity1 z x is m di/ant f ! e>?4 ,! vap\r1 !re=e1 :i* ! sun causes to exhale1 n only f seas1 riv]s1 & lakes1 b likewise f ! moi/ure on ! l&1 rises till x rea*es a region ( air ( its own specific gravity2 & !re1 y "k1 x w rema9 /ation>y4 ,by ! frequ5t accession ( fre% vap\r1 x gradually accumulates1 s z to =m ^? l>ge bodies ( vap\r1 :i* we call cl\ds3 & ! p>ticles1 at l5g? unit+1 become too heavy = ! air to support1 & fall to ! gr\nd4 ,c>ol9e4 ,!y d fall to ! gr\nd1 c]ta9ly1 :5 x ra9s2 b1 accord+ to y\r !ory1 ,i %\ld h imag9$1 t :5 ! cl\ds became too heavy1 = ! region ( air 9 :i* !y 7 situat$1 to support !m1 !y w\ld desc5d1 till !y rea*$ a /ratum ( air ( _! own weight1 & n fall to ! e>?2 = z cl\ds are =m$ ( vap\r1 !y _c be s heavy z ! l[e/ regions ( ! atmosph]e1 o!rwise ! vap\r w\ld n h ris54 ,mrs4 ,b4 ,if y exam9e ! mann] 9 :i* ! cl\ds desc5d1 x w obviate ?is objection4 ,9 fall+1 sev]al ( ! wat]y p>ticles come )9 ! sph]e ( ea* o!r's attraction1 & unite 9 ! =m ( a drop ( wat]4 ,! vap\r ?us trans=m$ into a %[]1 is heavi] ?an any "p ( ! atmosph]e1 & consequ5tly desc5ds to ! e>?4 ,c>ol9e4 ,h[ wond]fully curi\s6 ,mrs4 ,b4 ,x is impossible to consid] any "p ( nature att5tively1 )\t be+ /ruck ) admiration at ! wisdom x displays2 & ,i hope y w nev] contemplate ^! wond]s1 )\t feel+ y\r he>t gl[ ) admiration & gratitude1 t[>ds _! b\nte\s ,au?or4 ,obs]ve1 t if ! wat]s 7 nev] drawn out ( ! e>?1 all vegetation w\ld be de/roy$ by ! excess ( moi/ure2 if1 on ! o!r h&1 ! plants 7 n n\ri%$ & refre%$ by occasional %[]s1 ! dr\ght w\ld be equally fatal to !m4 ,if ! cl\ds con/antly rema9$ 9 a /ate ( vap\r1 !y might1 z y rem>k$1 desc5d into a heavi] /ratum ( ! atmosph]e1 b c\ld nev] fall to ! gr\nd2 or 7 ! p[] ( attraction m ?an suffici5t to conv]t ! vap\r into drops1 x w\ld trans=m ! cl\d into a mass ( wat]1 :i*1 in/ead ( n\ri%+1 w\ld de/roy ! produce ( ! e>?4 ,wat] !n asc5ds 9 ! =m ( vap\r1 & desc5ds 9 t ( ra91 sn[1 or hail1 all ( :i* ultimately become wat]4 ,"s ( ?is falls into ! v>i\s bodies ( wat] on ! surface ( ! globe1 ! rema9d] ^u ! l&4 ,( ! latt]1 "p reasc5ds 9 ! =m ( vap\r1 "p is absorb$ by ! roots ( vegetables1 & "p desc5ds into ! e>?1 :]e x =ms spr+s4 ,emily4 ,is !re !n no diff]5ce betwe5 ra9 wat]1 & spr+ wat]8 ,mrs4 ,b4 ,!y are orig9ally ! same2 b t portion ( ra9 wat] :i* goes to supply spr+s1 dissolves a numb] ( =eign p>ticles1 :i* x meets ) 9 its passage ?r\gh ! v>i\s soils x trav]ses4 ,c>ol9e4 ,yet spr+ wat] is m pleasant to ! ta/e1 appe>s m transp>5t1 &1 ,i %\ld h suppos$1 w\ld h be5 m pure ?an ra9 wat]4 ,mrs4 ,b4 ,no2 except+ di/ill$ wat]1 ra9 wat] is ! mo/ pure we c obta92 x is its purity :i* r5d]s x insipid2 :il/ ! v>i\s salts & diff]5t +r$i5ts1 dissolv$ 9 spr+ wat]1 give x a species ( flav\r1 :i* habit r5d]s agreeable2 ^! salts d n1 9 any degree1 affect its transp>5cy2 & ! filtration x und]goes1 ?r\gh gravel & s&1 cleanses x f all =eign matt]1 :i* x has n ! p[] ( dissolv+4 ,emily4 ,h[ is x t ! ra9 wat] does n cont9ue to desc5d by its gravity1 in/ead ( collect+ toge!r1 & =m+ spr+s8 ,mrs4 ,b4 ,:5 ra9 falls on ! surface ( ! e>?1 x cont9ues mak+ its way d[nw>ds ?r\gh ! pores & crevices 9 ! gr\nd4 ,:5 sev]al drops meet 9 _! subt]rane\s passage1 !y unite & =m a little rivulet2 ?is1 9 its progress1 meets ) o!r rivulets ( a simil> description1 & !y pursue _! c\rse toge!r )9 ! e>?1 till !y are /opp$ by "s sub/ance1 su* z rock1 or clay1 :i* !y _c p5etrate4 ,c>ol9e4 ,b y say t !re is "s reason to believe t wat] c p5etrate ev5 ! pores ( gold1 & x _c meet ) a sub/ance m d5se8 ,mrs4 ,b4 ,b if wat] p5etrate ! pores ( gold1 x is only :5 "u a /rong compressive =ce1 z 9 ! ,flor5t9e exp]im5t2 n[ 9 its passage t[>ds ! c5tre ( ! e>?1 x is act$ ^u by no o!r p[] ?an gravity1 :i* is n suffici5t to make x =ce its way1 ev5 ?r\gh a /ratum ( clay4 ,?is species ( e>?1 ?\gh n rem>kably d5se1 be+ ( great t5acity1 w n admit ! p>ticles ( wat] to pass4 ,:5 wat] enc\nt]s any sub/ance ( ?is nature1 !re=e1 its progress is /opp$1 & x is diffus$ ?r\gh ! por\s e>?1 & sometimes ! pressure ( ! accumulat+ wat]s1 =ms a b$1 or res]voir4 ,?is w be m cle>ly expla9$ by fig4 #i1 plate #ac1 :i* repres5ts a section1 ( ! int]ior ( a hill or m\nta94 ,a1 is a body ( wat]1 su* z ,i h describ$1 :i*1 :5 fill$ up z high z ,b1 7by ! cont9ual accession ( wat] x receives f ! ducts or rivulets a1 a1 a1 a17 f9ds a passage out ( ! cavity1 &1 impell$ by gravity1 x runs on1 till x makes its way out ( ! gr\nd at ! side ( ! hill1 & !re =ms a spr+1 ,c4 ,c>ol9e4 ,gravity impels d[nw>ds t[>ds ! c5tre ( ! e>?2 & ! spr+ 9 ?is figure runs 9 an horizontal direction4 ,mrs4 ,b4 ,n entirely4 ,!re is "s declivity f ! res]voir1 to ! spot :]e ! wat] issues out ( ! gr\nd2 & gravity1 y "k1 w br+ bodies d[n an incl9$ plane1 z well z 9 a p]p5dicul> direction4 ,c>ol9e4 ,b ?\gh ! spr+ may desc5d1 on fir/ issu+1 x mu/ aft]w>ds rise to rea* ! surface ( ! e>?2 & t is 9 direct opposition to gravity4 ,mrs4 ,b4 ,a spr+ c nev] rise above ! level ( ! res]voir :5ce x issues2 x mu/1 !re=e1 f9d a passage to "s "p ( ! surface ( ! e>?1 t is l[]1 or ne>] ! c5tre1 ?an ! res]voir4 ,x is true t1 9 ?is figure1 ! spr+ rises 9 its passage f ,b to ,c2 b ?is1 ,i ?9k1 ) a little reflection1 y w be able to acc\nt =4 ,emily4 ,oh1 yes2 x is ow+ to ! pressure ( fluids upw>ds2 & ! wat] rises 9 ! duct1 ^u ! same pr9ciple z x rises 9 ! sp\t ( a tea-pot2 t is to say1 9 ord] to pres]ve an equilibrium ) ! wat] 9 ! res]voir4 ,n[ ,i ?9k ,i und]/& ! nature ( spr+s3 ! wat] w fl[ ?r\gh a duct1 :e!r asc5d+ or desc5d+1 provid$ x nev] rises high] ?an ! res]voir4 ,mrs4 ,b4 ,wat] may ?us be convey$ to e "p ( a t[n1 & to ! upp] "p ( ! h\ses1 if x is orig9ally br\ght f a height1 sup]ior to any to :i* x is convey$4 ,h y nev] obs]v$1 :5 ! pavem5ts ( ! /reets h be5 m5d+1 ! pipes :i* s]ve z ducts = ! conveyance ( ! wat] ?r\gh ! t[n8 ,emily4 ,yes1 frequ5tly2 & ,i h rem>k$ t :5 any ( ^! pipes h be5 op5$1 ! wat] ru%es upw>ds f !m1 ) great velocity2 :i*1 ,i suppose1 proce$s f ! pressure ( ! wat] 9 ! res]voir1 :i* =ces x out4 ,c>ol9e4 ,i recollect hav+ once se5 a v curi\s glass1 call$ ,tantalus's cup2 x consi/s ( a goblet1 conta9+ a small figure ( a man1 & :atev] quantity ( wat] y p\r into ! goblet1 x nev] rises high] ?an ! brea/ ( ! figure4 ,d y "k h[ t is contriv$8 ,mrs4 ,b4 ,x is by means ( a syphon1 or b5t tube1 :i* is conceal$ 9 ! body ( ! figure4 ,?is tube rises ?r\gh "o ( ! legs1 z high z ! brea/1 & !re turn+1 desc5ds ?r\gh ! o!r leg1 & f !nce ?r\gh ! foot ( ! goblet1 :]e ! wat] runs out4 7fig4 #a1 plate #ad47 ,:5 y p\r wat] into ! glass ,a1 x mu/ rise 9 ! syphon ,b1 9 proportion z x rises 9 ! glass2 & :5 ! glass is fill$ to a level ) ! upp] "p ( ! syphon1 ! wat] w run out ?r\gh ! o!r leg ( ! figure1 & w cont9ue runn+ out1 z fa/ z y p\r x 92 !re=e ! glass c nev] fill any high]4 ,emily4 ,i ?9k ! new well t has be5 made at our c\ntry-h\se1 mu/ be ( t nature4 ,we _h a great sc>city ( wat]1 & my fa!r has be5 at consid]able exp5se to dig a well2 aft] p5etrat+ to a great dep?1 be=e wat] c\ld be f\nd1 a spr+ 0 at l5g? discov]$1 b ! wat] rose only a few feet above ! bottom ( ! well2 & sometimes x is q dry4 ,illu/ration3 ,,plate ,,xiv4 ,mrs4 ,b4 ,?is has1 h[ev]1 no analogy to ,tantalus's cup2 b is ow+ to ! v elevat$ situation ( y\r c\ntry-h\se4 ,emily4 ,i believe ,i guess ! reason4 ,!re _c be a res]voir ( wat] ne> ! summit ( a hill2 z 9 su* a situation1 !re w n be a suffici5t numb] ( rivulets =m$1 to supply "o2 & )\t a res]voir1 !re c be no spr+4 ,9 su* situations1 !re=e1 x is necess>y to dig v deep1 9 ord] to meet ) a spr+2 & :5 we give x v5t1 x c rise only z high z ! res]voir f :5ce x fl[s1 :i* w be b little1 z ! res]voir mu/ be situat$ at "s consid]able dep? bel[ ! summit ( ! hill4 ,c>ol9e4 ,y\r explanation appe>s v cle> & satisfactory2 b ,i c contradict x f exp]i5ce4 ,at ! v top ( a hill1 ne> our c\ntry-h\se1 !re is a l>ge pond1 &1 accord+ to y\r !ory1 x w\ld be impossible !re %\ld be spr+s 9 su* a situation to supply x ) wat]4 ,!n y "k t ,i h cross$ ! ,alps1 & ,i c assure y1 t !re is a f9e lake on ! summit ( ,m\nt ,c5is1 ! highe/ m\nta9 we pass$ ov]4 ,mrs4 ,b4 ,7 !re a lake on ! summit ( ,m\nt ,blanc1 :i* is ! highe/ ( ! ,alps1 x w\ld inde$ be wond]ful4 ,b t on ,m\nt ,c5is1 is n at all contradictory to our !ory ( spr+s2 = ?is m\nta9 is surr\nd$ by o!rs1 mu* m elevat$1 & ! spr+s :i* fe$ ! lake mu/ desc5d f res]voirs ( wat]1 =m$ 9 ^? m\nta9s4 ,?is mu/ also be ! case ) ! pond on ! top ( ! hill2 !re is d\btless "s m consid]able hill 9 ! neighb\rhood1 :i* supplies x ) wat]4 ,emily4 ,i compreh5d p]fectly1 :y ! wat] 9 our well nev] rises high3 b ,i d n und]/& :y x %\ld occasionally be dry4 ,mrs4 ,b4 ,because ! res]voir f :i* x fl[s1 be+ 9 an elevat$ situation1 is b scantily suppli$ ) wat]2 aft] a long dr\ght1 !re=e1 x may be dra9$1 & ! spr+ dry1 till ! res]voir be repl5i%$ by fre% ra9s4 ,x is n uncommon to see spr+s fl[ ) great viol5ce 9 wet seasons1 :i* at o!r times1 are p]fectly dry4 ,c>ol9e4 ,b !re is a spr+ 9 our gr\nds1 :i* m frequ5tly fl[s 9 dry1 ?an 9 wet wea!r2 h[ is t to be acc\nt$ =8 ,mrs4 ,b4 ,! spr+1 probably1 comes f a res]voir at a great di/ance1 & situat$ v deep 9 ! gr\nd3 x is1 !re=e1 "s l5g? ( "t be=e ! ra9 rea*es ! res]voir2 & ano!r consid]able portion mu/ elapse1 :il/ ! wat] is mak+ its way1 f ! res]voir1 to ! surface ( ! e>?2 s t ! dry wea!r may probably h succe$$ ! ra9s1 be=e ! spr+ beg9s to fl[2 & ! res]voir may be exhau/$1 by ! "t ! wet wea!r sets 9 aga94 ,c>ol9e4 ,i d\bt n b ?is is ! case1 z ! spr+ is 9 a v l[ situation1 !re=e1 ! res]voir may be at a great di/ance f x4 ,mrs4 ,b4 ,spr+s :i* d n con/antly fl[1 are call$ int]mitt+1 & are occasion$ by ! res]voir be+ imp]fectly suppli$4 ,indep5d5tly ( ! situation1 ?is is always ! case1 :5 ! duct1 or ducts1 :i* convey ! wat] into ! res]voir1 are small] ?an ^? :i* c>ry x (f4 ,c>ol9e4 ,if x runs out1 fa/] ?an x runs 91 x w ( c\rse sometimes be empty4 ,d n riv]s also1 d]ive _! s\rce f spr+s8 ,mrs4 ,b4 ,yes1 !y g5]ally take _! s\rce 9 m\nta9\s c\ntries1 :]e spr+s are mo/ abundant4 ,c>ol9e4 ,i und]/ood y t spr+s 7 m r>e1 9 elevat$ situations4 ,mrs4 ,b4 ,y d n consid] t m\nta9\s c\ntries1 ab\nd equally ) high1 & l[ situations4 ,res]voirs ( wat]1 :i* are =m$ 9 ! bosoms ( m\nta9s1 g5]ally f9d a v5t1 ei!r on _! declivity1 or 9 ! valley b5ea?2 :ile subt]rane\s res]voirs1 =m$ 9 a pla91 c seldom f9d a passage to ! surface ( ! e>?1 b rema9 conceal$1 unless discov]$ by digg+ a well4 ,:5 a spr+ once issues at ! surface ( ! e>?1 x cont9ues its c\rse ext]nally1 seek+ always a l[] gr\nd1 = x c no long] rise4 ,emily4 ,!n :at is ! consequ5ce1 if ! spr+1 or1 z ,i %\ld n[ r call x1 ! rivulet1 runs into a situation1 :i* is surr\nd$ by high] gr\nd8 ,mrs4 ,b4 ,its c\rse is /opp$2 ! wat] accumulates1 & x =ms a pool1 pond1 or lake1 accord+ to ! dim5sions ( ! body ( wat]4 ,! lake ( ,g5eva1 9 all probability1 owes its orig9 to ! ,rhone1 :i* passes ?r\gh x3 if1 :5 ! riv] fir/ ent]$ ! valley1 :i* n[ =ms ! b$ ( ! ,lake1 x f\nd itself surr\nd$ by high] gr\nds1 its wat]s w\ld !re accumulate1 till !y rose to a level ) t "p ( ! valley1 :]e ! ,rhone n[ cont9ues its c\rse beyond ! ,lake1 & f :5ce x fl[s ?r\gh valleys1 occasionally =m+ o!r small lakes1 till x rea*es ! sea4 ,emily4 ,& are n f\nta9s1 ( ! nature ( spr+s8 ,mrs4 ,b4 ,exactly4 ,a f\nta9 is conduct$ p]p5dicul>ly upw>ds1 by ! sp\t or adjutage ,a1 ?r\gh :i* x fl[s2 & x w rise ne>ly z high z ! res]voir ,b1 f :5ce x proce$s4 7,plate #ad4 fig4 #b47 ,c>ol9e4 ,:y n q z high8 ,mrs4 ,b4 ,because x meets ) resi/ance f ! air1 9 its asc5t2 & its motion is imp$$ by friction aga9/ ! sp\t1 :]e x ru%es out4 ,emily4 ,b if ! tube ?r\gh :i* ! wat] rises be smoo?1 c !re be any friction8 especially ) a fluid1 ^: p>ticles yield to ! slighte/ impression4 ,mrs4 ,b4 ,friction1 7z we obs]v$ 9 a =m] lesson17 may be dim9i%$ by poli%+1 b c nev] be entirely de/roy$2 & ?\gh fluids1 are less susceptible ( friction1 ?an solid bodies1 !y are /ill affect$ by x4 ,ano!r reason :y a f\nta9 w n rise s high z its res]voir1 is1 t z all ! wat] :i* sp\ts up1 has to desc5d aga91 x 9 do+ s1 presses1 or /rikes aga9/ ! "u p>ts1 & =ces !m sideways1 spread+ ! column into a head1 & r5d]+ x bo? wid]1 & %ort]1 ?an x o!rwise w\ld be4 ,at our next meet+1 we %all exam9e ! me*anical prop]ties ( ! air1 :i* be+ an ela/ic fluid1 diff]s 9 _m respects1 f liquids4 ,que/ions #a4 7,pg4 #abi7 ,:y d n ! frequ5t ra9s1 fill ! e>? ) wat]8 #b4 7,pg4 #abi7 ,:y w vap\r rise8 to :at height w x asc5d1 & :at w x =m8 #c4 7,pg4 #abi7 ,h[ may drops ( ra9 be =m$8 #d4 7,pg4 #acj7 ,:at becomes ( ! wat] aft] x has fall5 to ! e>?8 #e4 7,pg4 #acj7 ,:at is ! diff]5ce betwe5 ra9 wat]1 & t f spr+s8 #f4 7,pg4 #acj7 ,:y is ra9 m pure ?an spr+ wat]8 #g4 7,pg4 #acj7 ,:y is spr+ wat] m agreeable to ! palate8 #h4 7,pg4 #aca7 ,:at causes ! wat] to collect & =m spr+s8 #i4 7,pg4 #aca7 ,:y _c wat] p5etrate ?r\gh clay8 #aj4 7,pg4 #aca7 ,:at is repres5t$ by fig4 #i1 plate #ac8 #aa4 7,pg4 #acb7 ,h[ c y acc\nt = its ris+ upw>ds1 z repres5t$ at ,c8 #ab4 7,pg4 #acb7 ,9 convey+ wat] by means ( pipes1 h[ mu/ ! res]voir be situat$8 #ac4 7,pg4 #acb7 ,:at is ! in/rum5t call$1 :i* is repres5t$ 9 plate #ad1 fig4 #a1--;& h[ does x op]ate8 #ad4 7,pg4 #acc7 ,:y are wells r>ely well suppli$ ) wat]1 9 elevat$ situations8 #ae4 7,pg4 #acc7 ,:5 wat] is f\nd 9 elevat$ situations1 :5ce is x suppli$8 #af4 7,pg4 #acc7 ,wells & spr+s1 at "s p]iods well suppli$1 fail at o!rs2 h[ is ?is acc\nt$ =8 #ag4 7,pg4 #acd7 ,"s spr+s fl[ abundantly 9 dry wea!r1 :i* occasionally fail 9 wet wea!r1 h[ may ?is be expla9$8 #ah4 7,pg4 #acd7 ,:at is meant by int]mitt+ spr+s8 #ai4 7,pg4 #acd7 ,:5ce d riv]s1 9 g5]al1 d]ive _! wat]8 #bj4 7,pg4 #acd7 ,:y d spr+s ab\nd m 9 m\nta9\s1 ?an 9 level c\ntries8 #ba4 7,pg4 #ace7 ,h[ are lakes =m$8 #bb4 7,pg4 #ace7 ,:at causes wat] to rise 9 f\nta9s1 & h[ is ?is expla9$ by figure #b1 plate #ad8 #bc4 7,pg4 #ace7 ,:y w n ! f\nta9 rise to ! height ( ! wat] 9 ! res]voir8 ,,conv]sation ,,xii4 ,,on ,,! ,,me*anical ,,prop]ties ,,( ,,air4 ,,( ,,! ,,spr+ ,,or ,,ela/icity ,,( ,,! ,,air4 ,,( ,,! ,,weight ,,( ,,! ,,air4 ,,exp]im5ts ,,) ,,! ,,air ,,pump4 ,,( ,,! ,,b>omet]4 ,,mode ,,( ,,weigh+ ,,air4 ,,specific ,,gravity ,,( ,,air4 ,,( ,,pumps4 ,,description ,,( ,,! ,,suck+ ,,pump4 ,,description ,,( ,,! ,,=c+ ,,pump4 ,,mrs4 ,b4 ,at our la/ meet+ we exam9$ ! prop]ties ( fluids 9 g5]al1 & m p>ticul>ly ( su* z are call$ non-ela/ic fluids1 or liquids4 ,!re is ano!r class ( fluids1 di/+ui%$ by ! "n ( a]i=m1 or ela/ic fluids1 ! pr9cipal ( :i* is ! air we brea!1 :i* surr\nds ! e>?1 & is call$ ! atmosph]e4 ,emily4 ,!re are !n o!r k9ds ( air1 besides ! atmosph]e8 ,mrs4 ,b4 ,yes2 a great v>iety2 b !y diff] only 9 _! *emical1 & n 9 _! me*anical prop]ties2 & z x is ! latt] we are to exam9e1 we %all n at pres5t inquire into _! composition1 b conf9e our att5tion to ! me*anical prop]ties ( ela/ic fluids 9 g5]al4 ,c>ol9e4 ,& f :5ce arises ?is diff]5ce1 betwe5 ela/ic1 & non-ela/ic fluids8 ,mrs4 ,b4 ,!re is no attraction ( cohesion1 betwe5 ! p>ticles ( ela/ic fluids2 s t ! expansive p[] ( heat1 has no adv]s>y to cont5d )1 b gravity2 any increase ( temp]ature1 !re=e1 exp&s ela/ic fluids consid]ably1 & a dim9ution1 proportionally cond5ses !m4 ,! mo/ ess5tial po9t1 9 :i* air1 diff]s f o!r fluids is 9 its spr+ or ela/icity2 t is to say1 its p[] ( increas+1 or dim9i%+ 9 bulk1 accord+ly z x is m1 or less1 compress$3 a p[] ( :i* ,i h in=m$ y1 liquids are almo/ :olly depriv$4 ,emily4 ,i ?9k ,i und]/& ! ela/icity ( ! air v well f :at y =m]ly said ( x2 b :at p]plexes me is1 its hav+ gravity2 if x is heavy1 & we are surr\nd$ by x1 :y d we n feel its weight8 ,c>ol9e4 ,x mu/ be impossible to be s5sible ( ! weight ( su* inf9itely small p>ticles1 z ^? ( :i* ! air is compos$3 p>ticles :i* are too small to be se51 mu/ be too light to be felt4 ,mrs4 ,b4 ,y are mi/ak51 my de>2 ! air is mu* heavi] ?an y imag9e2 x is true1 t ! p>ticles :i* compose x1 are small2 b !n1 reflect on _! quantity3 ! atmosph]e ext5ds 9 height1 a great numb] ( miles f ! e>?1 & its gravity is su*1 t a man ( middl+ /ature1 is comput$ 7:5 ! air is heavie/7 to su/a9 ! weight ( ab\t #ad tons4 ,c>ol9e4 ,is x possible6 ,i %\ld h ?\ght su* a weight w\ld h cru%$ any "o to atoms4 ,mrs4 ,b4 ,t w\ld1 inde$1 be ! case1 if x 7 n = ! equality ( ! pressure1 on e "p ( ! body2 b :5 ?us diffus$1 we c be> ev5 a mu* great] weight1 )\t any consid]able inconv5i5ce4 ,9 ba?+ we support ! weight & pressure ( ! wat]1 9 addition to t ( ! atmosph]e2 b because ?is pressure is equally di/ribut$ ov] ! body1 we are sc>cely s5sible ( x2 :il/ if y\r %\ld]s1 y\r head1 or any p>ticul> "p ( y\r frame1 7 load$ ) ! additional weight ( a hundr$ p\nds1 y w\ld soon s9k "u ! fatigue4 ,besides ?is1 our bodies conta9 air1 ! spr+ ( :i*1 c\nt]balances ! weight ( ! ext]nal air1 & r5d]s u ins5sible ( its pressure4 ,c>ol9e4 ,b if x 7 possible to relieve me f ! weight ( ! atmosph]e1 %\ld ,i n feel m light & agile8 ,mrs4 ,b4 ,on ! contr>y1 ! air )9 y1 meet+ ) no ext]nal pressure to re/ra9 its ela/icity1 w\ld di/5d y\r body1 & at l5g? bur/+ "s ( ! p>ts :i* conf9$ x1 put a p]iod to y\r exi/5ce4 ,c>ol9e4 ,?is weight ( ! atmosph]e1 !n1 :i* ,i 0 s appreh5sive w\ld cru% me1 is1 9 reality1 ess5tial to my pres]vation4 ,emily4 ,i once saw a p]son cupp$1 & 0 told t ! swell+ ( ! "p "u ! cup1 0 produc$ by tak+ away f t "p1 ! pressure ( ! atmosph]e2 b ,i c\ld n und]/& h[ ?is pressure produc$ su* an effect4 ,mrs4 ,b4 ,! air pump af=ds u ! means ( mak+ a great v>iety ( int]e/+ exp]im5ts1 on ! weight1 & pressure ( ! air3 "s ( !m y h already se54 ,d y n recollect1 t 9 a vacuum produc$ )9 ! air pump1 sub/ances ( v>i\s weights1 fell to ! bottom 9 ! same "t2 :y does n ?is happ5 9 ! atmosph]e8 ,c>ol9e4 ,i rememb] y told u x 0 ow+ to ! resi/ance :i* light bodies meet )1 f ! air1 dur+ _! fall4 ,mrs4 ,b4 ,or1 9 o!r words1 to ! support :i* !y receiv$ f ! air1 & :i* prolong$ ! "t ( _! fall4 ,n[1 if ! air 7 de/itute ( weight1 h[ c\ld x support o!r bodies1 or ret>d _! fall8 ,i %all n[ %[ y "s o!r exp]im5ts1 :i* illu/rate1 9 a /rik+ mann]1 bo? ! weight1 & ela/icity ( air4 ,i %all tie a piece ( bladd] ov] ?is glass receiv]1 :i*1 y w obs]ve1 is op5 at ! top z well z bel[4 ,c>ol9e4 ,:y d y wet ! bladd] fir/8 ,mrs4 ,b4 ,x exp&s by wett+1 & contracts 9 dry+2 x is also m s(t & pliable :5 wet1 s t ,i c make x fit bett]1 & :5 dry1 x w be tight]4 ,we mu/ hold x to ! fire 9 ord] to dry x2 b n too ne>1 le/ x %\ld bur/ by sudd5 contraction4 ,let u n[ fix x on ! air pump1 & exhau/ ! air f und]nea? x--y w n be al>m$ if y he> a noise8 ,emily4 ,x 0 z l\d z ! report ( a gun1 & ! bladd] is bur/6 ,pray expla9 h[ ! air is conc]n$ 9 ?is exp]im5t4 ,mrs4 ,b4 ,x is ! effect ( ! weight ( ! atmosph]e1 on ! upp] surface ( ! bladd]1 :5 ,i _h tak5 away ! air f ! "u surface1 s t !re 0 no long] any reaction to c\nt]balance ! pressure ( ! atmosph]e1 on ! receiv]4 ,y obs]v$ h[ ! bladd] 0 press$ inw>ds1 by ! weight ( ! ext]nal air1 9 proportion z ,i exhau/$ ! receiv]3 & be=e a complete vacuum 0 =m$1 ! bladd]1 unable to su/a9 ! viol5ce ( ! pressure1 bur/ ) ! explosion y h j he>d4 ,i %all n[ %[ y an exp]im5t1 :i* proves ! expansion ( ! air1 conta9$ )9 a body1 :5 x is reliev$ f ! pressure ( ! ext]nal air4 ,y w\ld n imag9e t !re 0 any air conta9$ )9 ?is %rivell$ apple1 by its appe>ance2 b take notice ( x :5 plac$ )9 a receiv]1 f :i* ,i %all exhau/ ! air4 ,c>ol9e4 ,h[ /range6 x gr[s q plump1 & looks l a fre%-ga!r$ apple4 ,mrs4 ,b4 ,b z soon z ,i let ! air aga9 into ! receiv]1 ! apple1 y see1 returns to its %rivell$ /ate4 ,:5 ,i took away ! pressure ( ! atmosph]e1 ! air )9 ! apple1 exp&$1 & swell$ x out2 b ! in/ant ! atmosph]ic air 0 re/or$1 ! expansion ( ! int]nal air1 0 *eck$ & repress$1 & ! apple %runk to its =m] dim5sions4 ,y may make a simil> exp]im5t ) ?is little bladd]1 :i* y see is p]fectly flaccid1 & appe>s to conta9 no air3 9 ?is /ate ,i %all tie up ! neck ( ! bladd]1 s t :atev] air rema9s )9 x1 may n escape1 & !n place x "u ! receiv]4 ,n[ obs]ve1 z ,i exhau/ ! receiv]1 h[ ! bladd] di/5ds2 ?is proce$s f ! great dilatation ( ! small quantity ( air1 :i* 0 enclos$ )9 ! bladd]1 :5 ,i ti$ x up2 b z soon z ,i let ! air into ! receiv]1 t :i* ! bladd] conta9s1 cond5ses & %r9ks into its small compass1 )9 ! folds ( ! bladd]4 ,emily4 ,^! exp]im5ts are extremely amus+1 & !y af=d cle> pro(s1 bo? ( ! weight1 & ela/icity ( ! air2 b ,i %\ld l to "k1 exactly1 h[ mu* ! air weighs4 ,mrs4 ,b4 ,a column ( air rea*+ to ! top ( ! atmosph]e1 & ^: base is a squ>e in*1 weighs ab\t #ae lbs4 !re=e1 e squ>e in* ( our bodies1 su/a9s a weight ( #ae lbs43 & if y wi% to "k ! weight ( ! :ole ( ! atmosph]e1 y mu/ reckon h[ _m squ>e in*es !re are on ! surface ( ! globe1 & multiply !m by #ae4 ,emily4 ,b c we n asc]ta9 ! weight ( a small quantity ( air8 ,mrs4 ,b4 ,) p]fect ease4 ,i %all exhau/ ! air f ?is little bottle1 by means ( ! air pump3 & hav+ empti$ ! bottle ( air1 or1 9 o!r words1 produc$ a vacuum )9 x1 ,i secure x by turn+ ?is screw adapt$ to its neck3 we may n[ f9d ! exact weight ( ?is bottle1 by putt+ x into "o ( ! scales ( a balance4 ,x weighs1 y see1 j two ounces2 b :5 ,i turn ! screw1 s z to admit ! air into ! bottle1 ! scale :i* conta9s x1 prepond]ates4 ,c>ol9e4 ,no d\bt ! bottle fill$ ) air1 is heavi] ?an ! bottle void ( air2 & ! additional weight requir$ to br+ ! scales aga9 to a balance1 mu/ be exactly t ( ! air :i* ! bottle n[ conta9s4 ,mrs4 ,b4 ,t weight1 y see1 is almo/ two gra9s4 ,! dim5sions ( ?is bottle1 are six cubic in*es4 ,six cubic in*es ( air1 !re=e1 at ! temp]ature ( ?is room1 weighs ne>ly #b gra9s4 ,c>ol9e4 ,:y d y obs]ve ! temp]ature ( ! room1 9 e/imat+ ! weight ( ! air8 ,mrs4 ,b4 ,because heat r>efies air1 & r5d]s x light]2 !re=e ! w>m] ! air is1 :i* y weigh1 ! light] x w be4 ,if y %\ld n[ be desir\s ( kn[+ ! specific gravity ( ?is air1 we ne$ only fill ! same bottle1 ) wat]1 & ?us obta9 ! weight ( an equal quantity ( wat]--:i* y see is #aeae grs42 n[ by comp>+ ! weight ( wat]1 to t ( air1 we f9d x to be 9 ! proportion ( ab\t #hjj to #a4 ,z y are acqua9t$ ) decimal ari?metic1 y w und]/& :at ,i mean1 :5 ,i tell y1 t wat] be+ call$ #ajjj1 ! specific gravity ( air1 w be #a4b4 ,i w %[ y ano!r in/ance1 ( ! weight ( ! atmosph]e1 :i* ,i ?9k w please y3 y "k :at a b>omet] is8 ,c>ol9e4 ,x is an in/rum5t :i* indicates ! /ate ( ! wea!r1 by means ( a tube ( quicksilv]2 b h[1 ,i _c exactly say4 ,mrs4 ,b4 ,x is by %[+ ! weight ( ! atmosph]e1 :i* has great influ5ce on ! wea!r4 ,! b>omet]1 is an in/rum5t extremely simple 9 its con/ruction4 ,9 ord] t y may und]/& x1 ,i w %[ y h[ x is made4 ,i fir/ fill ) m]cury1 a glass tube ,a ,b1 7fig4 #c1 plate #ad47 ab\t ?ree feet 9 l5g?1 & op5 only at "o end2 !n /opp+ ! op5 end1 ) my f+]1 ,i imm]se x 9 a cup ,c1 conta9+ a little m]cury4 ,emily4 ,"p ( ! m]cury :i* 0 9 ! tube1 ,i obs]ve1 runs d[n into ! cup2 b :y does n ! :ole ( x subside1 = x is contr>y to ! law ( ! equilibrium ( fluids1 t ! m]cury 9 ! tube1 %\ld n desc5d to a level ) t 9 ! cup8 ,mrs4 ,b4 ,! m]cury t has fall5 f ! tube1 into ! cup1 has left a vacant space 9 ! upp] "p ( ! tube1 to :i* ! air _c ga9 access2 ?is space is !re=e a p]fect vacuum2 ! m]cury 9 ! tube1 is reliev$ f ! pressure ( ! atmosph]e1 :il/ t 9 ! cup1 rema9s expos$ to x4 ,c>ol9e4 ,oh1 n[ ,i und]/& x2 ! pressure ( ! air on ! m]cury 9 ! cup1 =ces x to rise 9 ! tube1 :]e !re is n any air to c\nt]act ! ext]nal pressure4 ,emily4 ,or r supports ! m]cury 9 ! tube1 & prev5ts x f fall+4 ,mrs4 ,b4 ,t comes to ! same ?+2 = ! p[] t c support m]cury 9 a vacuum1 w\ld also make x asc5d1 :5 x met ) a vacuum4 ,?us y see1 t ! equilibrium ( ! m]cury is de/roy$1 only to pres]ve ! g5]al equilibrium ( fluids4 ,c>ol9e4 ,b ?is simple app>atus is1 9 appe>ance1 v unlike a b>omet]4 ,mrs4 ,b4 ,x is all t is ess5tial to a b>omet]4 ,! tube & ! cup1 or a ci/]n ( m]cury1 are fix$ on a bo>d1 = ! conv5i5ce ( susp5d+ x2 ! brass plate on ! upp] "p ( ! bo>d1 is graduat$ into in*es1 & t5?s ( in*es1 = ! purpose ( asc]ta9+ ! height at :i* ! m]cury /&s 9 ! tube2 & ! small moveable metal plate1 s]ves to %[ t height1 ) great] accuracy4 ,emily4 ,& at :at height1 w ! weight ( ! atmosph]e su/a9 ! m]cury8 ,mrs4 ,b4 ,ab\t #bh or #bi in*es1 z y w see by ?is b>omet]2 b x dep5ds ^u ! weight ( ! atmosph]e1 :i* v>ies mu*1 9 diff]5t /ates ( ! wea!r4 ,! great] ! pressure ( ! air on ! m]cury 9 ! cup1 ! high] x w asc5d 9 ! tube4 ,n[ c y tell me :e!r ! air is heavi]1 9 wet1 or 9 dry wea!r8 ,c>ol9e4 ,)\t a mom5t's reflection1 ! air mu/ be heavie/ 9 wet wea!r4 ,x is s depress+1 & makes "o feel s heavy1 :ile 9 f9e wea!r1 ,i feel z light z a fea!r1 & z brisk z a bee4 ,mrs4 ,b4 ,w\ld x n h be5 bett] to h answ]$ ) a mom5t's reflection1 ,c>ol9e8 ,x w\ld h conv9c$ y1 t ! air mu/ be heavie/ 9 dry wea!r2 = x is !n1 t ! m]cury is f\nd to rise 9 ! tube1 & consequ5tly1 ! m]cury 9 ! cup1 mu/ be mo/ press$ by ! air4 ,c>ol9e4 ,:y !n does ! air feel s heavy1 9 bad wea!r8 ,mrs4 ,b4 ,because x is less salubri\s1 :5 impregnat$ ) damp4 ,! lungs1 "u ^! circum/ances1 d n play s freely1 nor does ! blood circulate s well2 ?us ob/ructions are frequ5tly occasion$ 9 ! small] vessels1 f :i* arise colds1 a/hmas1 agues1 fev]s1 c4 ,emily4 ,s9ce ! atmosph]e dim9i%es 9 d5sity1 9 ! upp] regions1 is n ! air m r>e1 ^u a hill1 ?an 9 a pla92 & does ! b>omet] indicate ?is diff]5ce8 ,mrs4 ,b4 ,c]ta9ly4 ,?is in/rum5t1 is s exact 9 its indications1 t x is us$ = ! purpose ( measur+ ! height ( m\nta9s1 & ( e/imat+ ! elevation ( balloons2 ! m]cury desc5d+ 9 ! tube1 z y asc5d to a great] height4 ,emily4 ,& is no inconv5i5ce exp]i5c$1 f ! ?9ness ( ! air1 9 su* elevat$ situations8 ,mrs4 ,b4 ,oh1 yes2 frequ5tly4 ,x is sometimes oppressive1 f be+ insuffici5t = respiration2 & ! expansion :i* takes place1 9 ! m d5se air conta9$ )9 ! body1 is (t5 pa9ful3 x occasions di/5tion1 & sometimes causes ! bur/+ ( ! small] blood-vessels1 9 ! nose1 & e>s4 ,besides 9 su* situations1 y are m expos$1 bo? to heat1 & cold2 = ?\gh ! atmosph]e is itself transp>5t1 its l[] regions1 ab\nd ) vap\rs1 & exhalations1 f ! e>?1 :i* float 9 x1 & act 9 "s degree z a cov]+1 :i* pres]ves u equally f ! int5sity ( ! sun's rays1 & f ! sev]ity ( ! cold4 ,c>ol9e4 ,pray1 ,mrs4 ,b41 is n ! !rmomet] con/ruct$ on ! same pr9ciples z ! b>omet]8 ,mrs4 ,b4 ,n at all4 ,! rise & fall ( ! fluid 9 ! !rmomet]1 is occasion$ by ! expansive p[] ( heat1 & ! cond5sation produc$ by cold3 ! air has no access to x4 ,an explanation ( x w\ld1 !re=e1 be irrelevant to our pres5t subject4 ,emily4 ,i h be5 reflect+1 t s9ce x is ! weight ( ! atmosph]e1 :i* supports ! m]cury1 9 ! tube ( a b>omet]1 x w\ld support a column ( any o!r fluid1 9 ! same mann]4 ,mrs4 ,b4 ,c]ta9ly2 b z m]cury1 is heavi] ?an all o!r fluids1 x w support a high] column1 ( any o!r fluid2 = two fluids are 9 equilibrium1 :5 _! height v>ies1 inv]sely z _! d5sities4 ,we f9d ! weight ( ! atmosph]e1 is equal to su/a9+ a column ( wat]1 = in/ance1 ( no less ?an #cb feet above its level4 ,c>ol9e4 ,! weight ( ! atmosph]e1 is !n1 z great z t ( a body ( wat] ( #cb feet 9 height4 ,mrs4 ,b4 ,precisely2 = a column ( air1 ( ! height ( ! atmosph]e1 is equal to a column ( wat] ( ab\t #cb feet1 or "o ( m]cury1 ( f #bh to #bi in*es4 ,! common pump1 is dep5d5t on ?is pr9ciple4 ,by ! act ( pump+1 ! pressure ( ! atmosph]e is tak5 (f ! wat]1 :i*1 9 consequ5ce1 rises4 ,! body ( a pump1 consi/s ( a l>ge tube or pipe1 ^: l[] end is imm]s$ 9 ! wat] :i* x is design$ to raise4 ,a k9d ( /opp]1 call$ a pi/on1 is fitt$ to ?is tube1 & is made to slide up & d[n x1 by means ( a metallic rod1 fa/5$ to ! c5tre ( ! pi/on4 ,emily4 ,is x n simil> to ! syr+e1 or squirt1 ) :i* y fir/ draw 91 & !n =ce out wat]8 ,mrs4 ,b4 ,x is2 b y "k t we d n wi% to =ce ! wat] out ( ! pump1 at ! same end ( ! pipe1 at :i* we draw x 94 ,! int5tion ( a pump1 is to raise wat] f a spr+1 or well2 ! pipe is1 !re=e1 plac$ p]p5dicul>ly ov] ! wat]1 :i* ent]s x at ! l[] extremity1 & x issues at a horizontal sp\t1 t[>ds ! upp] "p ( ! pump2 to effect ?is1 !re are1 besides ! pi/on1 two contrivances call$ valves4 ,! pump1 !re=e1 is r a m complicat$ piece ( ma*9]y1 ?an ! syr+e4 ,c>ol9e4 ,pray1 ,mrs4 ,b41 is n ! lea!r1 :i* cov]s ! op5+1 9 ! l[] bo>d ( a pair ( bell[s1 a k9d ( valve8 ,mrs4 ,b4 ,x is1 valves are made 9 v>i\s =ms2 any contrivance1 :i* all[s a fluid to pass 9 "o direction1 & prev5ts its return1 is call$ a valve2 t ( ! bell[s1 & ( ! common pump1 resemble ea* o!r1 exactly4 ,y c n[1 ,i ?9k1 und]/& ! /ructure ( ! pump4 ,its v>i\s p>ts1 are del9eat$ 9 ?is figure3 7fig4 #d4 plate #ad47 ,a ,b is ! pipe1 or body ( ! pump1 ,p ! pi/on1 ,v a valve1 or little door 9 ! pi/on1 :i*1 op5+ upw>ds1 admits ! wat] to rise ?r\gh x1 b prev5ts its return+1 & ,y1 is a simil> valve1 plac$ l[] d[n 9 ! body ( ! pump2 ,h is ! h&le1 :i* 9 ?is model1 s]ves to "w ! pi/on4 ,:5 ! pump is 9 a /ate ( inaction1 ! two valves are clos$ by _! own weight2 b :51 by work+ ! h&le ( ! pump1 ! pi/on asc5ds2 x raises a column ( air :i* re/$ ^u x1 & produces a vacuum1 betwe5 ! pi/on1 & ! l[] valve ,y2 ! air b5ea? ?is valve1 :i* is imm$iately ov] ! surface ( ! wat]1 consequ5tly exp&s1 & =ces its way ?r\gh x2 ! wat]1 !n1 reliev$ f ! pressure ( ! air1 asc5ds into ! pump4 ,a few /rokes ( ! h&le1 totally excludes ! air f ! body ( ! pump1 & fills x ) wat]1 :i*1 hav+ pass$ ?r\gh bo? ! valves1 runs out at ! sp\t4 ,c>ol9e4 ,i und]/& ?is p]fectly4 ,:5 ! pi/on is elevat$1 ! air1 & ! wat]1 successively rise 9 ! pump1 = ! same reason z ! m]cury1 rises 9 ! b>omet]4 ,emily4 ,i ?\ght t wat] 0 drawn up into a pump1 by suction1 9 ! same mann] z wat] may be suck$ ?r\gh a /raw4 ,mrs4 ,b4 ,x is s1 into ! body ( ! pump2 = ! p[] ( suction1 is no o!r ?an t ( produc+ a vacuum ov] "o "p ( ! liquid1 into :i* vacuum ! liquid is =c$1 by ! pressure ( ! atmosph]e1 on ano!r "p4 ,! action ( suck+ ?r\gh a /raw1 consi/s 9 draw+ 91 & conf9+ ! brea?1 s z to produce a vacuum 9 ! m\?2 9 consequ5ce ( :i*1 ! air )9 ! /raw1 ru%es into ! m\?1 & is foll[$ by ! liquid1 into :i*1 ! l[] end ( ! /raw1 is imm]s$4 ,! pr9ciple1 y see1 is ! same1 & ! only diff]5ce consi/s 9 ! mode ( produc+ a vacuum4 ,9 suction1 ! muscul> p[]s answ] ! purpose ( ! pi/on & valve4 ,emily4 ,wat] _c1 !n1 be rais$ by a pump1 above #cb feet2 = ! pressure ( ! atmosph]e w n su/a9 a column ( wat]1 above t height4 ,mrs4 ,b4 ,i beg y\r p>don4 ,x is true t !re mu/ nev] be s great a di/ance z #cb feet1 f ! level ( ! wat] 9 ! well1 to ! valve 9 ! pi/on1 o!rwise ! wat] w\ld n rise ?r\gh t valve2 b :5 once ! wat] has pass$ t op5+1 x is no long] ! pressure ( air on ! res]voir1 :i* makes x asc5d2 x is rais$ by lift+ x up1 z y w\ld raise x 9 a bucket1 ( :i* ! pi/on =m$ ! bottom4 ,?is common pump is1 !re=e1 call$ ! suck+1 or lift+ pump1 z x is con/ruct$ on bo? ^! pr9ciples4 ,! rod to :i* ! pi/on is atta*$1 mu/ be made suffici5tly long1 to all[ ! pi/on to be )9 #cb feet ( ! surface ( ! wat] 9 ! well1 h[ev] deep x may be4 ,!re is ano!r sort ( pump1 call$ ! =c+ pump3 x consi/s ( a =c+ p[]1 add$ to ! suck+ "p ( ! pump4 ,?is additional p[]1 is exactly on ! pr9ciple ( ! syr+e3 by rais+ ! pi/on1 y draw ! wat] into ! pump1 & by caus+ x to desc5d1 y =ce ! wat] out4 ,c>ol9e4 ,b ! wat] mu/ be =c$ out at ! upp] "p ( ! pump2 & ,i _c conceive h[ t c be done by ! desc5t ( ! pi/on4 ,mrs4 ,b4 ,figure #e1 plate #ad1 w expla9 ! difficulty4 ,! l>ge pipe1 ,a ,b1 repres5ts ! suck+ "p ( ! pump1 :i* diff]s f ! lift+ pump1 only 9 its pi/on ,p1 be+ unfurni%$ ) a valve1 9 consequ5ce ( :i* ! wat] _c rise above x4 ,:51 !re=e1 ! pi/on desc5ds1 x %uts ! valve ,y1 & =ces ! wat] 7:i* has no o!r v5t7 into ! pipe ,d3 ?is is likewise furni%$ ) a valve ,v1 :i*1 op5+ upw>ds1 admits ! wat] to pass1 b prev5ts its return4 ,! wat]1 is ?us fir/ rais$ 9 ! pump1 & !n =c$ into ! pipe1 by ! alt]nate asc5d+1 & desc5d+ motion ( ! pi/on1 aft] a few /rokes ( ! h&le to fill ! pipe1 f :5ce ! wat] issues at ! sp\t4 ,emily4 ,does n ! air pump1 :i* y us$ 9 ! exp]im5ts1 on pneumatics1 op]ate ^u ! same pr9ciples z ! suck+ pump8 ,mrs4 ,b4 ,exactly4 ,! air pump :i* ,i us$ 7plate #a1 fig4 #b17 has two holl[1 brass cyl9d]s1 call$ b>rels1 :i* are made p]fectly true4 ,9 ea* ( ^? b>rels1 !re is a pi/on2 ^! are work$ up1 & d[n1 by ! same h&le2 ! pi/ons1 are furni%$ ) valves1 op5+ upw>ds1 l ^? ( ! common pump3 !re are valves also1 plac$ at ! l[] "p ( ea* b>rel1 :i* op5 upw>ds2 !re are !re=e two pumps1 unit$ to produce ! same effect3 two tubes1 connect ^! b>rels ) ! plate1 ^u :i* ,i plac$ ! receiv]s1 :i* 7 to be exhau/$4 ,emily4 ,i n[ und]/& h[ ! air pump acts2 ! receiv] conta9s air1 :i* is exhau/$1 j z x is by ! common pump1 be=e ! wat] beg9s to rise4 ,mrs4 ,b4 ,hav+ expla9$ ! me*anical prop]ties ( air1 ,i ?9k x is n[ "t to conclude our lesson4 ,:5 next we meet1 ,i %all give y "s acc\nt ( w9d1 & ( s\nd1 :i* w t]m9ate our obs]vations on ela/ic fluids4 ,c>ol9e4 ,& ,i %all run into ! g>d51 to h ! pleasure ( pump+1 n[ t ,i und]/& ! con/ruction ( a pump4 ,mrs4 ,b4 ,&1 to-morr[1 ,i hope y w be able to tell me1 :e!r x is a =c+1 or a common lift+ pump4 ,que/ions #a4 7,pg4 #acf7 ,into :at two k9ds are fluids divid$8 #b4 7,pg4 #acf7 ,!re are diff]5t k9ds ( ela/ic fluids1 9 :at prop]ties are !y alike1 & 9 :at d !y diff]8 #c4 7,pg4 #acf7 ,9 :at p>ticul> d ela/ic1 diff] f non-ela/ic1 fluids8 #d4 7,pg4 #acf7 ,:at is meant by ! ela/icity ( air8 #e4 7,pg4 #acg7 ,:at is said respect+ ! weight ( ! atmosph]e8 #f4 7,pg4 #acg7 ,:y d we n feel ! pressure ( ! air8 #g4 7,pg4 #acg7 ,:at w\ld be ! effect ( reliev+ u f atmosph]ic pressure8 #h4 7,pg4 #ach7 ,h[ may ! weight ( ! air be %[n by ! aid ( ! air pump1 & a piece ( bladd]8 #i4 7,pg4 #ach7 ,h[ is ?is expla9$8 #aj4 7,pg4 #ach7 ,h[ may its ela/icity be exhibit$1 by an apple1 & by a bladd]8 #aa4 7,pg4 #aci7 ,:at is ! absolute weight ( a giv5 column ( atmosph]ic air1 & h[ c\ld its :ole pressure ^u ! e>? be asc]ta9$8 #ab4 7,pg4 #aci7 ,h[ c ! weight ( a small bulk ( air be f\nd8 #ac4 7,pg4 #adj7 ,9 asc]ta9+ ! weight ( air1 we take acc\nt ( its temp]ature--,:y8 #ad4 7,pg4 #adj7 ,h[ c\ld y asc]ta9 ! specific gravity ( air1 & :at w\ld x be8 #ae4 7,pg4 #adj7 ,:at are ! ess5tial p>ts ( a b>omet]1 z repres5t$ plate #ad1 fig4 #c8 #af4 7,pg4 #ada7 ,:at su/a9s ! m]cury 9 ! tube8 #ag4 7,pg4 #ada7 ,( :at use are ! divisions 9 ! upp] "p ( ! in/rum5t8 #ah4 7,pg4 #ada7 ,to :at height w ! m]cury rise1 & :at occasions ?is height to v>y8 #ai4 7,pg4 #ada7 ,:5 is ! m]cury highe/1 9 wet1 or 9 dry wea!r8 #bj4 7,pg4 #ada7 ,:at occasions ! s5sation ( oppression1 9 damp wea!r8 #ba4 7,pg4 #adb7 ,:y w ! b>omet] indicate ! height ( m\nta9s1 or ( balloons8 #bb4 7,pg4 #adb7 ,is any inconv5i5ce exp]i5c$ by p]sons asc5d+ to great heights1 & f :at cause8 #bc4 7,pg4 #adb7 ,:at occasions ! rise & fall ( ! m]cury1 9 a !rmomet]8 #bd4 7,pg4 #adb7 ,to :at height w ! pressure ( ! atmosph]e raise a column ( wat]8 #be4 7,pg4 #adb7 ,:at gov]ns ! diff]5ce betwe5 ! height ( ! m]cury1 & ( ! wat]8 #bf4 7,pg4 #adc7 ,h[ does ! common pump1 raise wat] f a well8 #bg4 7,pg4 #adc7 ,:at is meant by a pi/on8 #bh4 7,pg4 #adc7 ,describe ! con/ruction1 & use1 ( a valve4 #bi4 7,pg4 #adc7 ,:at are ! p>ts ( ! pump1 z repres5t$1 fig4 #d1 plate #ad48 #cj4 7,pg4 #add7 ,h[ d ^! p>ts act1 9 rais+ ! wat]8 #ca4 7,pg4 #add7 ,9 :at does t :i* is commonly call$ suction1 consi/8 #cb4 7,pg4 #add7 ,h[ mu/ ! pi/on be situat$ 9 ! pump8 #cc4 7,pg4 #add7 ,:at o!r k9d ( pump is describ$8 #cd4 7,pg4 #ade7 ,h[ is ! =c+ pump con/ruct$1 z %[n 9 plate #ad1 fig4 #e8 #ce4 7,pg4 #ade7 ,describe ! con/ruction & op]ation ( ! air pump1 7fig4 #b1 plate #a47 ,,conv]sation ,,xiii4 ,,on ,,w9d ,,& ,,s\nd4 ,,( ,,w9d ,,9 ,,g5]al4 ,,( ,,! ,,trade-,,w9d4 ,,( ,,! ,,p]iodical ,,trade-,,w9ds4 ,,( ,,! ,,a]ial ,,tides4 ,,( ,,s\nds ,,9 ,,g5]al4 ,,( ,,sonor\s ,,bodies4 ,,( ,,musical ,,s\nds4 ,,( ,,concord ,,or ,,h>mony1 ,,& ,,melody4 ,,mrs4 ,b4 ,well1 ,c>ol9e1 h y asc]ta9$ :at k9d ( pump y h 9 y\r g>d58 ,c>ol9e4 ,i ?9k x mu/ be m]ely a lift+ pump1 because no m =ce is requir$ to raise ! h&le ?an is necess>y to lift its weight2 & z 9 a =c+ pump1 by rais+ ! h&le1 y =ce ! wat] into ! small] pipe1 ! resi/ance ! wat] (f]s1 mu/ require an ex]tion ( /r5g?1 to ov]come x4 ,mrs4 ,b4 ,i make no d\bt y are "r2 = lift+ pumps1 be+ simple 9 _! con/ruction1 are by f> ! mo/ common4 ,i h promis$ to-day to give y "s acc\nt ( ! nature ( w9d4 ,w9d is no?+ m ?an ! motion ( a /ream1 or curr5t ( air1 g5]ally produc$ by a p>tial *ange ( temp]ature 9 ! atmosph]e2 = :5 any "o "p is m heat$ ?an ! re/1 t "p is r>efi$1 ! air 9 consequ5ce rises1 & ! equilibrium is de/roy$4 ,:5 ?is happ5s1 !re necess>ily foll[s a motion ( ! surr\nd+ air t[>ds t "p1 9 ord] to re/ore x2 ?is spot1 !re=e1 receives w9ds f e qu>t]4 ,^? :o live to ! nor? ( x1 exp]i5ce a nor? w9d2 ^? to ! s\?1 a s\? w9d3--d y compreh5d ?is8 ,c>ol9e4 ,p]fectly4 ,b :at sort ( wea!r mu/ ^? p h1 :o live on ! spot1 :]e ^! w9ds meet & int]f]e8 ,mrs4 ,b4 ,!y h mo/ commonly turbul5t & boi/]\s wea!r1 :irlw9ds1 hurricanes1 ra91 lightn+1 ?und]1 c4 ,?is /ormy wea!r occurs mo/ frequ5tly 9 ! torrid zone1 :]e ! heat is greate/3 ! air be+ m r>efi$ !re1 ?an 9 any o!r "p ( ! globe1 is light]1 & consequ5tly1 asc5ds2 :il/ ! air f ! nor? & s\?1 is cont9ually fl[+ 91 to re/ore ! equilibrium4 ,c>ol9e4 ,?is motion ( ! air1 w\ld produce a regul> & con/ant nor? w9d1 to ! inhabitants ( ! nor!rn hemisph]e2 & a s\? w9d1 to ^? ( ! s\!rn hemisph]e1 & cont9ual /orms at ! equator1 :]e ^! two adv]se w9ds w\ld meet4 ,mrs4 ,b4 ,^! w9ds d n meet1 = !y ea* *ange _! direction be=e !y rea* ! equator4 ,! sun1 9 mov+ ov] ! equatorial regions f ea/ to we/1 r>efies ! air z x passes1 & causes ! d5s] ea/]n air to fl[ we/w>ds1 9 ord] to re/ore ! equilibrium1 ?us produc+ a regul> ea/ w9d1 ab\t ! equator4 ,c>ol9e4 ,! air f ! we/1 !n1 con/antly goes to meet ! sun1 & repair ! di/urbance :i* 8 beams h produc$ 9 ! equilibrium ( ! atmosph]e4 ,b ,i wond] h[ y w reconcile ^! v>i\s w9ds1 ,mrs4 ,b42 y fir/ l$ me to suppose !re 0 a con/ant /ruggle betwe5 opposite w9ds at ! equator1 produc+ /orm & tempe/2 b n[ ,i he> ( "o regul> inv>iable w9d1 :i* mu/ naturally be att5d$ by calm wea!r4 ,emily4 ,i ?9k ,i compreh5d x3 d n ^! w9ds f ! nor? & s\?1 comb9e ) ! ea/]ly w9d ab\t ! equator1 & =m1 :at are call$1 ! trade-w9ds8 ,mrs4 ,b4 ,j s1 my de>4 ,! composition ( ! two w9ds1 nor? & ea/1 produces a con/ant nor?-ea/ w9d2 & t ( ! two w9ds1 s\? & ea/1 produces a regul> s\?-ea/ w9d2 ^! w9ds ext5d to ab\t ?irty degrees on ea* side ( ! equator1 ! regions fur!r di/ant f x1 exp]i5c+ only _! respective nor!rly & s\!rly w9ds4 ,c>ol9e4 ,b1 ,mrs4 ,b41 if ! air is con/antly fl[+ f ! poles1 to ! torrid zone1 !re mu/ be a defici5cy ( air1 9 ! pol> regions8 ,mrs4 ,b4 ,! light air ab\t ! equator1 :i* exp&s1 & rises into ! upp] regions ( ! atmosph]e1 ultimately fl[s f !nce1 back to ! poles1 to re/ore ! equilibrium3 if x 7 n = ?is res\rce1 ! pol>1 atmosph]ic regions1 w\ld soon be exhau/$ by ! /ream ( air1 :i*1 9 ! l[] /rata ( ! atmosph]e1 !y are con/antly s5d+ t[>ds ! equator4 ,c>ol9e4 ,!re is !n a sort ( circulation ( air 9 ! atmosph]e2 ! air 9 ! l[] /rata1 fl[+ f ! poles t[>ds ! equator1 & 9 ! upp] /rata1 fl[+ back f ! equator1 t[>ds ! poles4 ,mrs4 ,b4 ,exactly2 ,i c %[ y an example ( ?is circulation1 on a small] scale4 ,! air ( ?is room1 be+ m r>efi$1 ?an ! ext]nal air1 a w9d or curr5t ( air is p\r+ 9 f ! crevices ( ! w9d[s & doors1 to re/ore ! equilibrium2 b ! light air1 ) :i* ! room is fill$1 mu/ f9d "s v5t1 9 ord] to make way = ! heavy air t ent]s4 ,if y set ! door a-j>1 & hold a c&le ne> ! upp] "p ( x1 y w f9d t ! flame w be bl[n outw>ds1 %[+ t !re is a curr5t ( air fl[+ out f ! upp] "p ( ! room4--,n[ place ! c&le on ! floor1 close by ! door1 & y w p]ceive1 by ! incl9ation ( ! flame1 t !re is also a curr5t ( air1 sett+ into ! room4 ,c>ol9e4 ,x is j s2 ! upp] curr5t is ! w>m light air1 :i* is driv5 out to make way = ! /ream ( cold d5se air1 :i* ent]s ! room l[] d[n4 ,mrs4 ,b4 ,besides ! g5]al1 or trade-w9ds1 !re are o!rs1 :i* are call$ p]iodical1 because !y bl[ 9 contr>y directions1 at p>ticul> p]iods4 ,emily4 ,i h he>d1 ,mrs4 ,b41 t ! p]iodical w9ds1 call$1 9 ! torrid zone1 ! sea & l& breezes1 bl[ t[>ds ! l&1 9 ! day "t1 & t[>ds ! sea1 at night3 :at is ! reason ( t8 ,mrs4 ,b4 ,! l& reflects into ! atmosph]e1 a mu* great] quantity ( ! sun's rays1 ?an ! wat]2 !re=e1 t "p ( ! atmosph]e :i* is ov] ! l&1 is m heat$ & r>efi$1 ?an t :i* is ov] ! sea3 ?is occasions ! w9d to set 9 ^u ! l&1 z we f9d t x regul>ly does on ! coa/ ( ,gu9ea1 & o!r c\ntries 9 ! torrid zone4 ,!re1 !y h only ! sea breeze1 b on ! isl&s1 !y h1 9 g5]al1 bo? a l& & sea breeze1 ! latt] be+ produc$ 9 ! way describ$2 :il/ at night1 dur+ ! abs5ce ( ! sun1 ! e>? cools1 & ! air is consequ5tly cond5s$1 & fl[s f ! l&1 t[>ds ! sea1 occasion+ ! l& breeze4 ,emily4 ,i h he>d mu* ( ! viol5t tempe/s1 occasion$ by ! break+ up ( ! monsoons2 are n !y also regul> trade-w9ds8 ,mrs4 ,b4 ,!y are call$ p]iodical trade-w9ds1 z !y *ange _! c\rse e half ye>4 ,?is v>iation is produc$ by ! e>?'s annual c\rse r\nd ! sun2 ! nor? pole be+ incl9$ t[>ds t lum9>y "o half ( ! ye>1 ! s\? pole1 ! o!r half4 ,dur+ ! summ] ( ! nor!rn hemisph]e1 ! c\ntries ( ,arabia1 ,p]sia1 ,india1 & ,*9a1 are mu* heat$1 & reflect great quantities ( ! sun's rays into ! atmosph]e1 by :i* x becomes extremely r>efi$1 & ! equilibrium consequ5tly de/roy$4 ,9 ord] to re/ore x1 ! air f ! equatorial s\!rn regions1 :]e x is cold]1 7z well z f ! cold] nor!rn p>ts17 mu/ necess>ily h a motion t[>ds ^? p>ts4 ,! curr5t ( air f ! equatorial regions1 produces ! trade-w9ds = ! fir/ six mon?s1 9 all ! seas betwe5 ! heat$ cont95t ( ,asia1 & ! equator4 ,! o!r six mon?s1 :5 x is summ] 9 ! s\!rn hemisph]e1 ! ocean & c\ntries t[>ds ! s\!rn tropic are mo/ heat$1 & ! air ov] ^? p>ts1 m r>efi$3 !n ! air ab\t ! equator alt]s its c\rse1 & fl[s exactly 9 an opposite direction4 ,c>ol9e4 ,?is explanation ( ! monsoons is v curi\s2 b :at does _! break+ up mean8 ,mrs4 ,b4 ,x is ! "n giv5 by sailors to ! %ift+ ( ! p]iodical w9ds2 !y d n *ange _! c\rse sudd5ly1 b by degrees1 z ! sun moves f "o hemisph]e1 to ! o!r3 ?is *ange is usually att5d$ by /orms & hurricanes1 v dang]\s = %ipp+2 s t ^? seas are seldom navigat$ at ! season ( ! equ9oxes4 ,emily4 ,i ?9k ,i und]/& ! w9ds 9 ! torrid zone p]fectly well2 b :at is x t occasions ! great v>iety ( w9ds1 :i* occur 9 ! temp]ate zones8 =1 accord+ to y\r !ory1 !re %\ld be only nor? & s\? w9ds1 9 ^? climates4 ,mrs4 ,b4 ,s9ce s l>ge a portion ( ! atmosph]e1 z is ov] ! torrid zone1 is 9 cont9u$ agitation1 ^! agitations 9 an ela/ic fluid1 :i* yields to ! slighte/ impression1 mu/ ext5d e way1 to a great di/ance2 ! air1 !re=e1 9 all climates1 w suff] m or less p]turbation1 accord+ to ! situation ( ! c\ntry1 ! position ( m\nta9s1 valleys1 & a v>iety ( o!r causes3 h5ce x is easy to conceive1 t almo/ e climate1 mu/ be liable to v>iable w9ds2 ?is is p>ticul>ly ! case 9 high latitudes1 :]e ! e>? is less p[]fully affect$ by ! sun's rays1 ?an ne> ! equator4 ,c>ol9e4 ,i h obs]v$1 t ! w9d1 :i*ev] way x bl[s1 almo/ always falls ab\t sun-set4 ,mrs4 ,b4 ,because ! r>efaction ( air 9 ! p>ticul> spot :i* produces ! w9d1 dim9i%es z ! sun decl9es1 & consequ5tly ! velocity ( ! w9d1 abates4 ,emily4 ,s9ce ! air is a gravitat+ fluid1 is x n affect$ by ! attraction ( ! moon & ! sun1 9 ! same mann] z ! wat]s8 ,mrs4 ,b4 ,und\bt$ly2 b ! a]ial tides are z mu* great] ?an ^? ( wat]1 z ! d5sity ( wat] exce$s t ( air1 :i*1 z y may recollect1 we f\nd to be ab\t #hjj to #a4 ,c>ol9e4 ,:at a prodigi\s protub]ance t mu/ occasion6 ,h[ mu* ! weight ( su* a column ( air1 mu/ raise ! m]cury 9 ! b>omet]6 ,emily4 ,z ?is enorm\s tide ( air is drawn up & support$1 z x 71 by ! moon1 its weight & pressure1 ,i %\ld suppose1 w\ld be r dim9i%$ ?an increas$8 ,mrs4 ,b4 ,! weight ( ! atmosph]e is nei!r increas$ nor dim9i%$ by ! a]ial tides4 ,! moon's attraction augm5ts ! bulk1 z mu* z x dim9i%es ! weight1 ( ! column ( air2 ^! effects1 !re=e1 c\nt]balanc+ ea* o!r1 ! a]ial tides d n affect ! b>omet]4 ,c>ol9e4 ,i d n q und]/& t4 ,mrs4 ,b4 ,let u suppose t ! additional bulk ( air at high tide1 raises ! b>omet] "o in*2 & on ! o!r h&1 t ! support :i* ! moon's attraction af=ds ! air1 dim9i%es its weight or pressure1 s z to occasion ! m]cury to fall "o in*2 "u ^! circum/ances ! m]cury mu/ rema9 /ation>y4 ,?us1 y see1 t we c nev] be s5sible ( a]ial tides by ! b>omet]1 on acc\nt ( ! equality ( pressure ( ! atmosph]e1 :atev] be its height4 ,! exi/5ce ( a]ial tides is n1 h[ev]1 hypo!tical2 x is prov$ by ! effect !y produce on ! app>5t position ( ! heav5ly bodies2 b ?is ,i _c expla9 to y1 till y und]/& ! prop]ties ( light4 ,emily4 ,& :5 %all we le>n !m8 ,mrs4 ,b4 ,i %all fir/ expla9 to y ! nature ( s\nd1 :i* is intimately connect$ ) t ( air2 & ,i ?9k at our next meet+1 we may ent] ^u ! subject ( optics4 ,we h n[ consid]$ ! effects produc$ by ! wide1 & ext5d$ agitation1 ( ! air2 b !re is ano!r k9d ( agitation1 ( :i* ! air is susceptible--a vibratory trembl+ motion1 :i*1 /rik+ on ! drum ( ! e>1 produces s\nd4 ,c>ol9e4 ,is n s\nd produc$ by solid bodies8 ,! voice ( animals1 ! r++ ( bells1 ! music ( in/rum5ts1 all proce$ f solid bodies4 ,i "k ( no s\nd b t ( ! w9d1 :i* is produc$ by ! air4 ,mrs4 ,b4 ,s\nd1 ,i assure y1 results f a tremul\s motion ( ! air2 & ! sonor\s bodies y enum]ate1 are m]ely ! in/rum5ts by :i* t peculi> species ( motion1 is communicat$ to ! air4 ,c>ol9e4 ,:at6 :5 ,i r+ ?is little bell1 is x ! air t s\nds1 & n ! bell8 ,mrs4 ,b4 ,bo? ! bell1 & ! air1 are conc]n$ 9 ! production ( s\nd4 ,b s\nd1 /rictly speak+1 is a p]ception excit$ 9 ! m9d1 by ! motion ( ! air1 on ! n]ves ( ! e>2 ! air1 !re=e1 z well z ! sonor\s bodies :i* put x 9 motion1 is only ! cause ( s\nd1 ! imm$iate effect is produc$ by ! s5se ( he>+3 = )\t ?is s5se1 !re w\ld be no s\nd4 ,emily4 ,i c ) difficulty conceive t4 ,a p]son born deaf1 x is true1 has no idea ( s\nd1 because he he>s none2 yet t does n prev5t ! real exi/5ce ( s\nd1 z all ^? :o are n deaf1 c te/ify4 ,mrs4 ,b4 ,i d n d\bt ! exi/5ce ( s\nd1 to all ^? :o possess ! s5se ( he>+2 b x exi/s nei!r 9 ! sonor\s body1 nor 9 ! air1 b 9 ! m9d ( ! p]son ^: e> is /ruck1 by ! vibratory motion ( ! air1 produc$ by a sonor\s body4 ,s\nd1 !re=e1 is a s5sation1 produc$ 9 a liv+ body2 life1 is z necess>y to its exi/5ce1 z x is to t ( feel+ or see+4 ,to conv9ce y t s\nd does n exi/ 9 sonor\s bodies1 b t air or "s o!r vehicle1 is necess>y to its production1 endeav\r to r+ ! little bell1 aft] ,i h susp5d$ x "u a receiv] 9 ! air pump1 f :i* ,i %all exhau/ ! air4444 ,c>ol9e4 ,?is is inde$ v /range3 ?\gh ,i agitate x s viol5tly1 x produces b little s\nd4 ,mrs4 ,b4 ,by exhau/+ ! receiv]1 ,i h cut (f ! communication betwe5 ! air & ! bell2 ! latt]1 !re=e1 _c imp>t its motion1 to ! air4 ,c>ol9e4 ,are y sure t x is n ! glass1 :i* cov]s ! bell1 t prev5ts our he>+ x8 ,mrs4 ,b4 ,t y may easily asc]ta91 by lett+ ! air into ! receiv]1 & !n r++ ! bell4 ,c>ol9e4 ,v true2 ,i c he> x n[1 almo/ z l\d1 z if ! glass did n cov] x2 & ,i c no long] d\bt b t air is necess>y to ! production ( s\nd4 ,mrs4 ,b4 ,n absolutely necess>y1 ?\gh by f> ! mo/ common vehicle ( s\nd4 ,liquids1 z well z air1 are capable ( convey+ ! vibratory motion ( a sonor\s body1 to ! organ ( he>+2 z s\nd c be he>d "u wat]4 ,solid bodies also1 convey s\nd1 z ,i c soon conv9ce y by a v simple exp]im5t4 ,i %all fa/5 ?is /r+ by ! middle1 r\nd ! pok]2 n[ raise ! pok] f ! gr\nd1 by ! two ends ( ! /r+1 & hold "o to ea* ( y\r e>s3--,i %all n[ /rike ! pok]1 ) a key1 & y w f9d t ! s\nd is convey$ to ! e> by means ( ! /r+s1 9 a mu* m p]fect mann]1 ?an if x _h no o!r vehicle ?an ! air4 ,c>ol9e4 ,t x is1 c]ta9ly1 = ,i am almo/ /unn$ by ! noise4 ,b :at is a sonor\s body1 ,mrs4 ,b48 = all bodies are capable ( produc+ "s k9d ( s\nd1 by ! motion !y communicate to ! air4 ,mrs4 ,b4 ,^? bodies are call$ sonor\s1 :i* produce cle>1 di/9ct1 regul>1 & durable s\nds1 su* z a bell1 a drum1 musical /r+s1 w9d in/rum5ts1 c4 ,!y owe ?is prop]ty to _! ela/icity2 = an ela/ic body1 aft] hav+ be5 /ruck1 n only returns to its =m] situation1 b hav+ acquir$ mom5tum by its velocity1 l ! p5dulum1 x spr+s out on ! opposite side4 ,if ,i draw ! /r+ ,a ,b1 7fig4 #f1 plate #ad17 :i* is made fa/ at bo? ends1 to ,c1 x w n only return to its orig9al position1 b proce$ onw>ds1 to ,d4 ,?is is its fir/ vibration2 at ! end ( :i*1 x w reta9 suffici5t velocity to br+ x to ,e1 & back aga9 to ,f1 :i* con/itutes its second vibration2 ! ?ird vibration1 w c>ry x only to ,g & ,h1 & s on1 till ! resi/ance ( ! air de/roys its motion4 ,! vibration ( a sonor\s body1 gives a tremul\s motion to ! air ar\nd x1 v simil> to ! motion communicat$ to smoo? wat]1 :5 a /one is ?r[n into x4 ,?is1 fir/ produces a small circul> wave1 ar\nd ! spot 9 :i* ! /one falls2 ! wave spreads1 & gradually communicates its motion to ! adjac5t wat]s1 produc+ simil> waves to a consid]able ext5t4 ,! same k9d ( waves are produc$ 9 ! air1 by ! motion ( a sonor\s body1 b ) ?is diff]5ce1 t z air1 is an ela/ic fluid1 ! motion does n consi/ ( regul>ly ext5d+ waves1 b ( vibrations2 & are compos$ ( a motion1 =w>ds & backw>ds1 simil> to ^? ( ! sonor\s body4 ,!y diff] also1 9 ! "o tak+ place 9 a plane1 ! o!r1 9 all directions3 ! a]ial undulations1 be+ sph]ical4 ,emily4 ,b if ! air moves backw>ds1 z well z =w>ds1 h[ c its motion ext5d s z to convey s\nd to a di/ance8 ,mrs4 ,b4 ,! fir/ sph]e ( undulations1 :i* are produc$ imm$iately ar\nd ! sonor\s body1 by press+ aga9/ ! contigu\s air1 cond5ses x4 ,! cond5s$ air1 ?\gh impell$ =w>d by ! pressure1 reacts on ! fir/ set ( undulations1 driv+ !m back aga94 ,! second set ( undulations :i* h be5 put 9 motion1 9 _! turn1 communicate _! motion1 & are !mselves driv5 back1 by reaction4 ,?us1 !re is a succession ( waves 9 ! air1 correspond+ ) ! succession ( waves 9 ! wat]4 ,c>ol9e4 ,! vibrations ( s\nd1 mu/ ext5d mu* fur!r ?an ! circul> waves 9 wat]1 s9ce s\nd is convey$ to a great di/ance4 ,mrs4 ,b4 ,! air is a fluid s mu* less d5se ?an wat]1 t motion is m easily communicat$ to x4 ,! report ( a cannon produces vibrations ( ! air1 :i* ext5d to sev]al miles ar\nd4 ,emily4 ,di/ant s\nd takes "s "t to rea* u1 s9ce x is produc$ at ! mom5t ! cannon is fir$2 & we see ! light ( ! fla%1 long be=e we he> ! report4 ,mrs4 ,b4 ,! air is imm$iately put 9 motion1 by ! fir+ ( a cannon2 b x requires "t = ! vibrations to ext5d to any di/ant spot4 ,! velocity ( s\nd1 is comput$ to be at ! rate ( #aadb feet 9 a second4 ,c>ol9e4 ,) :at a/oni%+ rapidity ! vibrations mu/ be communicat$6 ,b ! velocity ( s\nd v>ies1 ,i suppose1 ) t ( ! air :i* conveys x4 ,if ! w9d sets t[>ds u f ! cannon1 we mu/ he> ! report soon] ?an if x set ! o!r way4 ,mrs4 ,b4 ,! direction ( ! w9d makes less diff]5ce 9 ! velocity ( s\nd1 ?an y w\ld imag9e4 ,if ! w9d sets f u1 x be>s mo/ ( ! a]ial waves away1 & r5d]s ! s\nd fa9t]2 b x is n v consid]ably long] 9 rea*+ ! e>1 ?an if ! w9d blew t[>ds u4 ,?is uni=m velocity ( s\nd1 enables u to det]m9e ! di/ance ( ! object1 f :i* x proce$s2 z t ( a vessel at sea1 fir+ a cannon1 or t ( a ?und] cl\d4 ,if we d n he> ! ?und]1 till half a m9ute aft] we see ! lightn+1 we conclude ! cl\d to be at ! di/ance ( six miles & a half4 ,emily4 ,pray1 h[ is ! s\nd ( an e*o produc$8 ,mrs4 ,b4 ,:5 ! a]ial vibrations meet ) an ob/acle1 hav+ a h>d & regul> surface1 su* z a wall1 or rock1 !y are reflect$ back to ! e>1 & produce ! same s\nd a second "t2 b ! s\nd w !n appe> to proce$1 f ! object by :i* x is reflect$4 ,if ! vibrations fall p]p5dicul>ly on ! ob/acle1 !y are reflect$ back 9 ! same l9e2 if obliquely1 ! s\nd returns obliquely1 9 ! opposite direction1 ! angle ( reflection be+ equal to ! angle ( incid5ce4 ,c>ol9e4 ,oh1 !n1 ,emily1 ,i n[ und]/& :y ! e*o ( my voice beh9d our h\se is he>d s mu* pla9] by y ?an x is by me1 :5 we /& at ! opposite ends ( ! gravel walk4 ,my voice1 or r1 ,i %\ld say1 ! vibrations ( air x occasions1 fall obliquely on ! wall ( ! h\se1 & are reflect$ by x1 to ! opposite end ( ! gravel walk4 ,emily4 ,v true2 & we h obs]v$1 t :5 we /& 9 ! middle ( ! walk1 opposite ! h\se1 ! e*o returns to ! p]son :o spoke4 ,mrs4 ,b4 ,speak+-trumpets1 are con/ruct$ on ! pr9ciple1 t s\nd is reflect$4 ,! voice1 in/ead ( be+ diffus$ 9 ! op5 air1 is conf9$ )9 ! trumpet2 & ! vibrations :i* w\ld o!rwise spread lat]ally1 fall aga9/ ! sides ( ! in/rum5t1 & are reflect$ f ! diff]5t po9ts ( incid5ce1 s z to comb9e ) ^? vibrations :i* proce$ /raight =w>ds4 ,! vibrations are ?us =c$ onw>ds1 9 ! direction ( ! trumpet1 s z greatly to increase ! s\nd1 to a p]son situat$ 9 t direction4 ,figure #g1 plate #ad1 w give y a cle>] idea1 ( ! speak+-trumpet2 9 ?is1 l9es are drawn to repres5t ! mann]1 9 :i* we may imag9e ! s\nd to be reflect$4 ,!re is a po9t 9 front ( ! trumpet1 ,f1 :i* is d5om9at$ its focus1 because ! s\nd is !re m int5se1 ?an at any o!r spot4 ,! trumpet us$ by deaf p]sons1 acts on ! same pr9ciple2 al?\gh x does n equally increase ! s\nd4 ,emily4 ,are ! trumpets us$ z musical in/rum5ts1 also con/ruct$ on ?is pr9ciple8 ,mrs4 ,b4 ,s f> z _! =m t5ds to increase ! s\nd1 !y are2 b1 z a musical in/rum5t1 ! trumpet becomes itself ! sonor\s body1 :i* is made to vibrate by bl[+ into x1 & communicates its vibrations to ! air4 ,i w attempt to give y1 9 a few words1 "s notion ( ! nature ( musical s\nds1 :i*1 z y are fond ( music1 mu/ be int]e/+ to y4 ,if a sonor\s body be /ruck 9 su* a mann]1 t its vibrations1 are all p]=m$ 9 regul> times1 ! vibrations ( ! air1 w correspond ) !m2 & /rik+ 9 ! same regul> mann] on ! drum ( ! e>1 w produce ! same uni=m s5sation1 on ! auditory n]ve1 & excite ! same uni=m idea1 9 ! m9d2 or1 9 o!r words1 we %all he> "o musical tone4 ,b if ! vibrations ( ! sonor\s body1 are irregul>1 !re w necess>ily foll[ a confusion ( a]ial vibrations2 = a second vibration may comm5ce1 be=e ! fir/ is f9i%$1 meet x half way on its return1 int]rupt x 9 its c\rse1 & produce h>% j>r+ s\nds1 :i* are call$ discords4 ,emily4 ,b ea* set ( ^! irregul> vibrations1 if repeat$ alone1 & at equal int]vals1 w\ld1 ,i suppose1 produce a musical tone8 ,x is only _! irregul> int]f]5ce1 :i* occasions discord4 ,mrs4 ,b4 ,c]ta9ly4 ,! quick] a sonor\s body vibrates1 ! m acute1 or %>p1 is ! s\nd produc$2 & ! sl[] ! vibrations1 ! m grave w be ! note4 ,c>ol9e4 ,b if ,i /rike any "o note ( ! piano-=te1 repeat$ly1 :e!r quickly or sl[ly1 x always gives ! same tone4 ,mrs4 ,b4 ,because ! vibrations ( ! same /r+1 at ! same degree ( t5sion1 are always ( a simil> duration4 ,! quickness1 or sl[ness ( ! vibrations1 relate to ! s+le tones1 n to ! v>i\s s\nds :i* !y may compose1 by succe$+ ea* o!r4 ,/rik+ ! note 9 quick succession1 produces a m frequ5t repetition ( ! tone1 b does n increase ! velocity ( ! vibrations ( ! /r+4 ,! duration ( ! vibrations ( /r+s1 or wires1 dep5ds ^u _! l5g?1 _! ?ickness1 or weight1 & _! degree ( t5sion3 ?us1 y f9d1 ! l[ bass notes are produc$ by long1 ?ick1 loose /r+s2 & ! high treble notes by %ort1 small1 & tight /r+s4 ,c>ol9e4 ,!n1 ! diff]5t l5g?1 & size1 ( ! /r+s ( musical in/rum5ts1 s]ve to v>y ! duration ( ! vibrations1 & consequ5tly1 ! acut5ess or gravity ( ! notes8 ,mrs4 ,b4 ,yes4 ,among ! v>iety ( tones1 !re are "s :i*1 s\nd$ toge!r1 please ! e>1 produc+ :at we call h>mony1 or concord4 ,?is arises f ! agreem5t ( ! vibrations ( ! two sonor\s bodies2 s t "s ( ! vibrations ( ea*1 /rike ^u ! e> at ! same "t4 ,?us1 if ! vibrations ( two /r+s are p]=m$ 9 equal times1 ! same tone is produc$ by bo?1 & !y are said to be 9 unison4 ,emily4 ,n[1 !n1 ,i und]/& :y1 :5 ,i tune my h>p1 9 unison ) ! piano-=te1 ,i draw ! /r+s tight]1 if x is too l[1 or loos5 !m1 if x is too high a pit*3 x is 9 ord] to br+ !m to vibrate1 9 equal times1 ) ! /r+s ( ! piano-=te4 ,mrs4 ,b4 ,b concord1 y "k1 is n conf9$ to unison2 = two diff]5t tones1 h>monize 9 a v>iety ( cases4 ,:5 ! vibrations ( "o /r+ 7or o!r sonor\s body7 vibrate 9 d\ble ! "t ( ano!r1 ! second vibration ( ! latt]1 w /rike ^u ! e>1 at ! same in/ant1 z ! fir/ vibration ( ! =m]2 & ?is is ! concord ( an octave4 ,if ! vibrations ( two /r+s are z two to ?ree1 ! second vibration ( ! fir/1 corresponds ) ! ?ird vibration ( ! latt]1 produc+ ! h>mony call$1 a fif?4 ,c>ol9e4 ,s1 !n1 :5 ,i /rike ! key-note ) its fif?1 ,i he> e second vibration ( "o1 & e ?ird ( ! o!r1 at ! same "t8 ,mrs4 ,b4 ,yes2 & ! key-note1 /ruck ) ! f\r?1 is likewise a concord1 because ! vibrations1 are z ?ree to f\r4 ,! vibrations ( a major ?ird1 ) ! key-note1 are z f\r to five2 & ^? ( a m9or ?ird1 z five to six4 ,!re are o!r tones1 :i*1 ?\gh !y _c be /ruck toge!r )\t produc+ discord1 if /ruck successively1 give u t succession ( pleas+ s\nds1 :i* is call$ melody4 ,h>mony1 y p]ceive1 arises f ! comb9$ effect ( two1 or m concordant s\nds1 :ile melody1 is ! result ( c]ta9 simple s\nds1 :i* succe$ ea* o!r4 ,^u ^! g5]al pr9ciples1 ! sci5ce ( music is f\nd$2 b1 ,i am n suffici5tly acqua9t$ ) x1 to ent] into x any fur!r4 ,we %all n[1 !re=e1 take leave ( ! subject ( s\nd2 &1 at our next int]view1 ent] ^u t ( optics1 9 :i* we %all consid] ! nature ( light1 vision1 & col\rs4 ,que/ions #a4 7,pg4 #adf7 ,:at is w9d1 & h[ is x g5]ally produc$8 #b4 7,pg4 #adf7 ,h[ d ! w9ds bl[1 ar\nd ! place :]e ! air becomes r>efi$8 #c4 7,pg4 #adf7 ,:at effect is likely to be produc$ :]e ! w9ds meet8 #d4 7,pg4 #adg7 ,9 :at "p ( ! globe is ! air mo/ r>efi$1 & :at is ! consequ5ce8 #e4 7,pg4 #adg7 ,h[ d ^! w9ds *ange _! direction z !y approa* ! equator8 #f4 7,pg4 #adg7 ,h[ are ! trade-w9ds produc$1 & h[ f> d !y ext5d8 #g4 7,pg4 #adg7 ,h[ is ! equilibrium 9 ! air re/or$8 #h4 7,pg4 #adh7 ,h[ c contr>y curr5ts ( air be %[n 9 a room8 #i4 7,pg4 #adh7 ,:at causes ?is8 #aj4 7,pg4 #adh7 ,:at is meant by a p]iodical w9d8 #aa4 7,pg4 #adh7 ,:at occasions ! l& & sea breezes1 & :]e d !y prevail8 #ab4 7,pg4 #adi7 ,:at are monsoons8 #ac4 7,pg4 #adi7 ,h[ d !y *ange1 & :at is ! cause8 #ad4 7,pg4 #adi7 ,:at is meant by _! break+ up1 & :at effect is 9 g5]al produc$8 #ae4 7,pg4 #adi7 ,:y is ! w9d mo/ v>iable 9 high latitudes8 #af4 7,pg4 #aej7 ,:y is ! w9d apt to less5 ab\t sunset8 #ag4 7,pg4 #aej7 ,:at effect mu/ ! sun & moon produce ^u ! atmosph]e1 f _! attraction8 #ah4 7,pg4 #aej7 ,:y d n ! a]ial tides affect ! b>omet]8 #ai4 7,pg4 #aea7 ,h[ is s\nd produc$8 #bj4 7,pg4 #aea7 ,does s\nd exi/ 9 ! sonor\s body1 if n1 :at is x8 #ba4 7,pg4 #aea7 ,by :at exp]im5t might we prove t air is ! pr9cipal vehicle ( s\nd8 #bb4 7,pg4 #aeb7 ,:at o!r bodies convey s\nd1 & h[ c x be %[n t !y d s8 #bc4 7,pg4 #aeb7 ,:at is meant by a sonor\s body8 #bd4 7,pg4 #aeb7 ,to :at d !y owe ?is prop]ty8 #be4 7,pg4 #aeb7 ,h[ is ?is expla9$ by fig4 #f1 plate #ad8 #bf4 7,pg4 #aeb7 ,h[ is x illu/rat$ by a /one ?r[n into wat]1 & h[ f> does ?is illu/ration apply8 #bg4 7,pg4 #aec7 ,h[ are ! vibrations propagat$8 #bh4 7,pg4 #aec7 ,h[ c we prove t s\nd1 does n travel z rapidly z light8 #bi4 7,pg4 #aec7 ,at :at rate is s\nd said to travel8 #cj4 7,pg4 #aec7 ,is ! velocity mu* influ5c$ by ! direction ( ! w9d8 #ca4 7,pg4 #aec7 ,h[ w s\nd enable u to judge ( ! di/ance ( objects8 #cb4 7,pg4 #aed7 ,h[ are e*oes produc$8 #cc4 7,pg4 #aed7 ,:at is ! op]ation & effect ( ! speak+-trumpet 7fig4 #g1 plate #ad78 #cd4 7,pg4 #aee7 ,h[ is a musical tone produc$8 #ce4 7,pg4 #aee7 ,:at occasions discords8 #cf4 7,pg4 #aee7 ,^u :at does ! acut5ess or gravity ( a s\nd dep5d8 #cg4 7,pg4 #aee7 ,does ! =ce1 ) :i* a /r+ is /ruck1 affect ! rapidity ( its vibrations8 #ch4 7,pg4 #aee7 ,h[ are ! /r+s made to produce ! high & l[ notes8 #ci4 7,pg4 #aee7 ,:at is meant by h>mony1 or concord1 & h[ is x produc$8 #dj4 7,pg4 #aef7 ,:5 are /r+s said to be 9 unison8 #da4 7,pg4 #aef7 ,h[ are octaves produc$8 #db4 7,pg4 #aef7 ,h[ are fif?s produc$8 #dc4 7,pg4 #aef7 ,h[ major & m9or ?irds8 #dd4 7,pg4 #aef7 ,:at is meant by melody1 & 9 :at p>ticul> does x diff] f h>mony8 ,illu/ration3 ,,plate ,,xv4 ,,conv]sation ,,xiv4 ,,on ,,optics4 ,,( ,,lum9\s1 ,,transp>5t1 ,,& ,,opaque ,,bodies4 ,,( ,,! ,,radiation ,,( ,,light4 ,,( ,,%ad[s4 ,,( ,,! ,,reflection ,,( ,,light4 ,,opaque ,,bodies ,,se5 ,,only ,,by ,,reflect$ ,,light4 ,,vision ,,expla9$4 ,,cam]a ,,obscura4 ,,image ,,( ,,objects ,,on ,,! ,,ret9a4 ,,c>ol9e4 ,i long to beg9 our lesson to-day1 ,mrs4 ,b41 = ,i expect t x w be v ent]ta9+4 ,mrs4 ,b4 ,optics is t bran* ( philosophy1 :i* treats ( ! nature & prop]ties ( light4 ,x is c]ta9ly "o ( ! mo/ int]e/+ bran*es ( ,natural ,philosophy1 b n "o ( ! easie/ to und]/&2 ,i mu/1 !re=e1 beg t y w give me y\r undivid$ att5tion4 ,i %all fir/ inquire1 :e!r y compreh5d ! mean+ ( a lum9\s body1 an opaque body1 & a transp>5t body4 ,c>ol9e4 ,a lum9\s body is "o t %9es2 an opaque4444 ,mrs4 ,b4 ,d n proce$ to ! second1 until we h agre$ ^u ! def9ition ( ! fir/4 ,all bodies t %9e1 are n lum9\s2 = a lum9\s body is "o t %9es by its own light2 z ! sun1 ! fire1 a c&le1 c4 ,emily4 ,poli%$ metal !n1 :5 x %9es ) s mu* brilliancy1 is n a lum9\s body8 ,mrs4 ,b4 ,no1 = x w\ld be d>k1 if x did n receive light f a lum9\s body2 x belongs1 !re=e1 to ! class ( d>k1 z well z ( opaque bodies1 :i* compreh5ds all su* z are nei!r lum9\s1 nor w admit ! light to pass ?r\gh !m4 ,emily4 ,& transp>5t bodies1 are ^? :i* admit ! light to pass ?r\gh !m1 su* z glass & wat]4 ,mrs4 ,b4 ,y are "r4 ,transp>5t1 or pellucid bodies1 are frequ5tly call$ m$iums1 because !y all[ ! rays ( light to pass ?r\gh !m2 & ! rays :i* pass ?r\gh1 are said to be transmitt$ by !m4 ,light1 :5 emanat$ f ! sun1 or any o!r lum9\s body1 is project$ =w>d 9 /raight l9es1 9 e possible direction2 s t ! lum9\s body1 is n only ! g5]al c5tre1 f :5ce all ! rays proce$2 b e po9t ( x1 may be consid]$ z a c5tre1 :i* radiates light 9 e direction4 7,fig4 #a1 plate #ae47 ,emily4 ,b d n ! rays :i* are project$ 9 diff]5t directions1 & cross ea* o!r1 int]f]e1 & imp$e ea* o!r's c\rse8 ,mrs4 ,b4 ,n at all4 ,! p>ticles ( light1 are s extremely m9ute1 t !y are nev] kn[n to int]f]e ) ea* o!r4 ,a ray ( light1 is a s+le l9e ( light1 project$ f a lum9\s body2 & a p5cil ( rays1 is a collection ( rays1 proce$+ f any "o po9t ( a lum9\s body1 z fig4 #b4 ,c>ol9e4 ,is light !n a sub/ance compos$ ( p>ticles1 l o!r bodies8 ,mrs4 ,b4 ,t is a disput$ po9t1 ^u :i* ,i _c pret5d to decide4 ,9 "s respects1 light is ob$i5t to ! laws :i* gov]n bodies2 9 o!rs1 x appe>s to be indep5d5t ( !m3 ?us1 ?\gh its c\rse is guid$ by ! laws ( motion1 x does n seem to be influ5c$ by ^? ( gravity4 ,x has nev] be5 discov]$ to h weight1 ?\gh a v>iety ( int]e/+ exp]im5ts h be5 made ) a view ( asc]ta9+ t po9t2 b we are s ignorant ( ! intimate nature ( light1 t an attempt to inve/igate x1 w\ld lead u into a labyr9? ( p]plexity1 if n ( error2 we %all1 !re=e1 conf9e our att5tion to ^? prop]ties ( light1 :i* are well asc]ta9$4 ,let u return to ! exam9ation ( ! effects ( ! radiation ( light1 f a lum9\s body4 ,s9ce ! rays ( light are project$ 9 /raight l9es1 :5 !y meet ) an opaque body ?r\gh :i* !y are unable to pass1 !y are /opp$ %ort 9 _! c\rse2 = !y _c move 9 a curve l9e r\nd ! body4 ,c>ol9e4 ,no1 c]ta9ly2 = x w\ld require "s o!r =ce besides t ( projection1 to produce motion 9 a curve l9e4 ,mrs4 ,b4 ,! int]ruption ( ! rays ( light1 by ! opaque body1 produces1 !re=e1 d>kness on ! opposite side ( x3 & if ?is d>kness fall ^u a wall1 a %eet ( pap]1 or any object :atev]1 x =ms a %ad[4 ,emily4 ,a %ad[1 !n1 is no?+ m ?an d>kness produc$ by ! int]v5tion ( an opaque body1 :i* prev5ts ! rays ( light f rea*+ an object beh9d x4 ,c>ol9e4 ,:y !n are %ad[s ( diff]5t degrees ( d>kness2 = ,i %\ld h suppos$1 f y\r def9ition ( a %ad[1 t x w\ld h be5 p]fectly black8 ,mrs4 ,b4 ,x frequ5tly happ5s t a %ad[ is produc$ by an opaque body1 int]rupt+ ! c\rse ( ! rays f "o lum9\s body1 :ile light f ano!r1 rea*es ! space :]e ! %ad[ is =m$2 9 :i* case1 ! %ad[ is proportionally fa9t]4 ,?is happ5s :5 ! opaque body is light$ by two c&les3 if y ext+ui% "o ( !m1 ! %ad[ w be bo? deep]1 & m di/9ct4 ,c>ol9e4 ,b yet x w n be p]fectly d>k4 ,mrs4 ,b4 ,because x is /ill slightly illum9at$ by light reflect$ f ! walls ( ! room1 & o!r surr\nd+ objects4 ,y mu/ obs]ve1 also1 t :5 a %ad[ is produc$ by ! int]ruption ( rays f a s+le lum9\s body1 ! d>kness is proportion$ to ! int5sity ( ! light4 ,emily4 ,i %\ld h suppos$ ! contr>y2 = z ! light reflect$ f surr\nd+ objects on ! %ad[1 mu/ be 9 proportion to ! int5sity ( ! light1 ! /rong] ! light1 ! m ! %ad[ w be illum9$4 ,mrs4 ,b4 ,y\r rem>k is p]fectly j2 b z we h no means ( e/imat+ ! degrees ( light1 & ( d>kness1 b by comp>ison1 ! /ronge/ light w appe> to produce ! deepe/ %ad[4 ,h5ce a total eclipse ( ! sun1 occasions a m s5sible d>kness ?an midnight1 z x is imm$iately contra/$ ) ! /rong light ( noonday4 ,c>ol9e4 ,! reappe>ance ( ! sun1 aft] an eclipse1 mu/1 by ! same contra/1 appe> rem>kably brilliant4 ,mrs4 ,b4 ,c]ta9ly4 ,!re are sev]al ?+s to be obs]v$1 9 reg>d to ! =m1 & ext5t1 ( %ad[s4 ,if ! lum9\s body ,a 7fig4 #c47 is l>g] ?an ! opaque body ,b1 ! %ad[ w gradually dim9i% 9 size1 till x t]m9ates 9 a po9t4 ,c>ol9e4 ,?is is ! case ) ! %ad[s ( ! e>?1 & ! moon2 z ! sun1 :i* illum9es !m1 is l>g] ?an ei!r ( ^? bodies4 ,& :y is x n ! case ) ! %ad[s ( t]re/rial objects8 ,_! %ad[s1 f> f dim9i%+1 are always l>g] ?an ! object1 & increase ) ! di/ance f x4 ,mrs4 ,b4 ,9 e/imat+ ! effect ( %ad[s1 we mu/ consid] ! dim5sions ( ! lum9\s body2 :5 ! lum9\s body is less1 ?an ! opaque body1 ! %ad[ w increase ) ! di/ance4 ,?is w be be/ exemplifi$1 by obs]v+ ! %ad[ ( an object light$ by a c&le4 ,emily4 ,i h (t5 notic$1 t ! %ad[ ( my figure1 aga9/ ! wall1 gr[s l>g]1 z x is m di/ant f me1 :i* is ow+1 no d\bt1 to ! c&le t %9es on me1 be+ mu* small] ?an myself4 ,mrs4 ,b4 ,yes4 ,! %ad[ ( a figure z ,a1 7fig4 #d47 v>ies 9 size1 accord+ to ! di/ance ( ! sev]al surfaces ,b ,c ,d ,e1 on :i* x is describ$4 ,c>ol9e4 ,i h obs]v$1 t two c&les1 produce two %ad[s f ! same object2 :il/ x w\ld appe>1 f :at y said1 t !y %\ld r produce only half a %ad[1 t is to say1 a v fa9t "o4 ,mrs4 ,b4 ,! numb] ( lights 79 diff]5t directions7 :ile x decreases ! int5sity ( ! %ad[s1 increases _! numb]1 :i* always corresponds ) t ( ! lights2 = ea* light1 makes ! opaque body ca/ a diff]5t %ad[1 z illu/rat$ by fig4 #e4 :i* repres5ts a ball ,a1 light$ by ?ree c&les1 ,b1 ,c1 ,d2 & y obs]ve ! light ,b1 produces ! %ad[ b1 ! light ,c1 ! %ad[ c1 & ! light ,d1 ! %ad[ d2 b nei!r ( ^! %ad[s w be v d>k1 because ! light ( "o c&le only1 is int]cept$ by ! ball2 & ! spot is /ill illum9at$ by ! o!r two4 ,emily4 ,i ?9k we n[ und]/& ! nature ( %ad[s v well2 b pray1 :at becomes ( ! rays ( light1 :i* opaque bodies arre/ 9 _! c\rse1 & ! int]ruption ( :i*1 is ! occasion ( %ad[s8 ,mrs4 ,b4 ,y\r "q leads to a v important prop]ty ( light1 ,reflection4 ,:5 rays ( light enc\nt] an opaque body1 !y _c pass ?r\gh x1 & "p ( !m are absorb$ by x1 & "p are reflect$1 & reb\nd2 j z an ela/ic ball reb\nds1 :5 /ruck aga9/ a wall4 ,by reflection1 we mean t ! light is turn$ back aga91 ?r\gh ! same m$ium :i* x _h trav]s$ 9 its fir/ c\rse4 ,emily4 ,& is light1 9 its reflection1 gov]n$ by ! same laws1 z solid1 ela/ic bodies8 ,mrs4 ,b4 ,exactly4 ,if a ray ( light fall p]p5dicul>ly on an opaque body1 x is reflect$ back 9 ! same l9e1 t[>ds ! po9t :5ce x proce$$4 ,if x fall obliquely1 x is reflect$ obliquely1 b 9 ! opposite direction2 ! ray :i* falls ^u ! reflect+ surface1 is call$ ! incid5t ray1 & t :i* leaves x1 ! reflect$ ray2 ! angle ( incid5ce1 is always equal to ! angle ( reflection4 ,y recollect t law 9 me*anics8 ,emily4 ,oh yes1 p]fectly4 ,mrs4 ,b4 ,if y w %ut ! %utt]s1 we w admit a ray ( ! sun's light1 ?r\gh a v small ap]ture1 & ,i c %[ y h[ x is reflect$4 ,i n[ hold ?is mirror1 s t ! ray %all fall p]p5dicul>ly ^u x4 ,c>ol9e4 ,i see ! ray :i* falls ^u ! mirror1 b n t :i* is reflect$ by x4 ,mrs4 ,b4 ,because x is turn$ directly back aga92 & ! ray ( incid5ce1 & t ( reflection1 are conf\nd$ toge!r1 bo? be+ 9 ! same l9e1 ?\gh 9 opposite directions4 ,emily4 ,! ray !n1 :i* appe>s to u s+le1 is really d\ble1 & is compos$ ( ! incid5t ray1 proce$+ to ! mirror1 & ( ! reflect$ ray1 return+ f ! mirror4 ,mrs4 ,b4 ,exactly s4 ,we w n[ sep>ate !m1 by hold+ ! mirror ,m1 7fig4 #f17 9 su* a mann]1 t ! incid5t ray1 ,a ,b1 %all fall obliquely ^u x--y see ! reflect$ ray1 ,b ,c1 is m>*+ (f 9 ano!r direction4 ,if we draw a l9e f ! po9t ( incid5ce ,b1 p]p5dicul>ly1 to ! mirror1 x w divide ! angle ( incid5ce1 f ! angle ( reflection1 & y w see t !y are equal4 ,emily4 ,exactly2 & n[1 t y hold ! mirror1 s t ! ray falls m obliquely ^u x1 x is also reflect$ m obliquely1 pres]v+ ! equality ( ! angles ( incid5ce1 & ( reflection4 ,mrs4 ,b4 ,x is by reflect$ rays only1 t we see opaque objects4 ,lum9\s bodies1 s5d rays ( light imm$iately to our eyes1 b ! rays :i* !y s5d to o!r bodies1 are invisible to u1 & are se51 only :5 !y are reflect$ by ^? bodies1 to our eyes4 ,emily4 ,b h we n j se5 ! ray ( light1 9 its passage f ! sun to ! mirror1 & its reflections8 yet1 9 nei!r case1 7 ^? rays 9 a direction to ent] our eyes4 ,mrs4 ,b4 ,:at y saw1 0 ! light reflect$ to y\r eyes1 by small p>ticles ( du/ float+ 9 ! air1 & on :i* ! ray %one1 9 its passage to1 & f1 ! mirror4 ,c>ol9e4 ,yet ,i see ! sun1 %9+ on t h\se yond]1 z cle>ly z possible4 ,mrs4 ,b4 ,inde$ y _c see a s+le ray1 :i* passes f ! sun to ! h\se2 y see1 by ! aid ( ^? rays1 :i* ent] y\r eyes2 !re=e1 x is ! rays :i* are reflect$ by ! h\se1 to y1 & n ^? :i* proce$ directly f ! sun1 to ! h\se1 t r5d] ! build+ visible to y4 ,c>ol9e4 ,:y !n does "o side ( ! h\se appe> to be 9 sun%9e1 & ! o!r 9 %ade8 =1 if ,i _c see ! sun %9e ^u x1 ! :ole ( ! h\se %\ld appe> 9 ! %ade4 ,mrs4 ,b4 ,t side ( ! h\se1 :i* ! sun %9es ^u1 receives1 & reflects m light1 & !re=e1 appe>s m lum9\s & vivid1 ?an ! side :i* is 9 %ad[2 = ! latt] is illum9$ only1 by rays reflect$ ^u x by o!r objects2 ^! rays are1 !re=e1 twice reflect$ be=e !y rea* y\r sight2 & z light is m1 or less1 absorb$ by ! bodies x /rikes ^u1 e "t a ray is reflect$1 its int5sity is dim9i%$4 ,c>ol9e4 ,/ill ,i _c reconcile to myself1 ! idea t we d n see ! sun's rays %9+ on objects1 b only ^? :i* su* objects reflect to u4 ,mrs4 ,b4 ,i d n1 h[ev]1 despair ( conv9c+ y ( x4 ,look at t l>ge %eet ( wat]2 c y tell :y ! sun appe>s to %9e on "o "p ( x only8 ,c>ol9e4 ,no1 inde$2 = ! :ole ( x is equally expos$ to ! sun4 ,?is p>tial brilliancy ( wat]1 has (t5 excit$ my wond]2 b x has /ruck me m p>ticul>ly by moonlight4 ,i h frequ5tly obs]v$ a vivid /reak ( moon%9e on ! sea1 :ile ! re/ ( ! wat] rema9$ 9 deep obscurity1 & yet !re 0 no app>5t ob/acle to prev5t ! moon f %9+ equally on e "p ( ! wat]4 ,mrs4 ,b4 ,by moonlight ! effect is m rem>kable1 on acc\nt ( ! deep obscurity ( ! o!r p>ts ( ! wat]2 :ile by ! sun's light1 ! effect is too /rong = ! eye to be able to obs]ve x s di/9ctly4 ,c>ol9e4 ,b1 if ! sun really %9es on e "p ( t %eet ( wat]1 :y does n e "p ( x1 reflect rays to my eyes8 ,mrs4 ,b4 ,! reflect$ rays1 are n attract$ out ( _! natural c\rse1 by y\r eyes4 ,! direction ( a reflect$ ray1 y "k1 dep5ds on t ( ! incid5t ray2 ! sun's rays1 !re=e1 :i* fall ) v>i\s degrees ( obliquity ^u ! wat]1 are reflect$ 9 directions equally v>i\s2 "s ( ^! w meet y\r eyes1 & y w see !m1 b ^? :i* fall else:]e1 are invisible to y4 ,c>ol9e4 ,! /reak ( sun%9e1 !n1 :i* we n[ see ^u ! wat]1 is compos$ ( ^? rays :i* by _! reflection1 happ5 to fall ^u my eyes8 ,mrs4 ,b4 ,precisely4 ,emily4 ,b is t side ( ! h\se yond]1 :i* appe>s to be 9 %ad[1 really illum9at$ by ! sun1 & its rays reflect$ ano!r way8 ,mrs4 ,b4 ,no2 t is a diff]5t case1 f ! %eet ( wat]4 ,t side ( ! h\se1 is really 9 %ad[2 x is ! we/ side1 :i* ! sun _c %9e ^u1 till ! aft]noon4 ,emily4 ,^? objects1 !n1 :i* are illum9$ by reflect$ rays1 & ^? :i* receive direct rays f ! sun1 b :i* d n reflect ^? rays t[>ds u1 appe> equally 9 %ad[8 ,mrs4 ,b4 ,c]ta9ly2 = we see !m bo? illum9$ by reflect$ rays4 ,t "p ( ! %eet ( wat]1 ov] :i* ! trees ca/ a %ad[1 by :at light d y see x8 ,emily4 ,s9ce x is n by ! sun's direct rays1 x mu/ be by ^? reflect$ on x f o!r objects1 & :i* x aga9 reflects to u4 ,c>ol9e4 ,b if we see all t]re/rial objects by reflect$ light1 7z we d ! moon17 :y d !y appe> s bright & lum9\s8 ,i %\ld h suppos$ t reflect$ rays1 w\ld h be5 dull & fa9t1 l ^? ( ! moon4 ,mrs4 ,b4 ,! moon reflects ! sun's light1 ) z mu* vividness z any t]re/rial object4 ,if y look at x on a cle> night1 x w appe> z bright z a %eet ( wat]1 ! walls ( a h\se1 or any object se5 by daylight1 & on :i* ! sun %9es4 ,! rays ( ! moon are d\btless feeble1 :5 comp>$ ) ^? ( ! sun2 b t w\ld n be a fair comp>ison1 = ! =m] are incid5t1 ! latt]1 reflect$ rays4 ,c>ol9e4 ,true2 & :5 we see t]re/rial objects by moonlight1 ! light has be5 twice reflect$1 & is consequ5tly1 proportionally fa9t]4 ,mrs4 ,b4 ,9 trav]s+ ! atmosph]e1 ! rays1 bo? ( ! sun1 & moon1 lose "s ( _! light4 ,= ?\gh ! pure air1 is a transp>5t m$ium1 :i* transmits ! rays ( light freely1 we h obs]v$1 t ne> ! surface ( ! e>?1 x is load$ ) vap\rs & exhalations1 by :i* "s portion ( !m are absorb$4 ,c>ol9e4 ,i h (t5 notic$1 t an object on ! summit ( a hill1 appe>s m di/9ct1 ?an "o at an equal di/ance 9 a valley1 or a pla92 :i* is ow+1 ,i suppose1 to ! air be+ m free f vap\rs 9 an elevat$ situation1 & ! reflect$ rays1 be+ consequ5tly bright]4 ,mrs4 ,b4 ,t may h "s s5sible effect2 b1 :5 an object on ! summit ( a hill1 has a back gr\nd ( light sky1 ! contra/ ) ! object1 makes its outl9e m di/9ct4 ,c>ol9e4 ,i n[ feel well satisfi$1 t we see opaque objects1 only by reflect$ rays2 b ,i d n und]/&1 h[ ^! rays1 %[ u ! objects f :i* !y proce$4 ,mrs4 ,b4 ,i %all h]eaft] describe ! /ructure ( ! eye1 v p>ticul>ly1 b w n[ obs]ve1 t ! small r\nd spot1 :i* is g5]ally call$ ! sight ( ! eye1 is prop]ly d5om9at$ ! pupil2 & t ! ret9a1 is an expansion ( ! optic n]ve on ! back "p ( ! ball ( ! eye1 ^u :i*1 z ^u a scre51 ! rays fall1 :i* ent] at ! pupil4 ,! rays ( light1 ent] at ! pupil ( ! eye1 & proce$ to ! ret9a2 & !re !y describe ! figure1 col\r1 & 7except+ size7 =m a p]fect repres5tation ( ! object1 f :i* !y proce$4 ,we %all aga9 close ! %utt]s1 & admit ! light1 ?r\gh ! small hole made = t purpose1 & y w see a picture1 on ! wall1 opposite ! ap]ture1 simil> to t :i* is del9eat$ on ! ret9a ( ! eye4 ,! picture is some:at confus$1 b by us+ a l5s1 to br+ ! rays to a focus1 x w be r5d]$ v di/9ct4 ,c>ol9e4 ,oh1 h[ wond]ful6 ,!re is an exact picture 9 m9iature ( ! g>d51 ! g>d5] at "w1 ! trees bl[n ab\t by ! w9d4 ,! l&scape1 w\ld be p]fect1 if x 7 n rev]s$2 ! gr\nd1 be+ above1 & ! sky b5ea?4 ,mrs4 ,b4 ,x is n en\gh to admire1 y mu/ und]/&1 ?is ph5om5on1 :i* is call$ a cam]a obscura1 or d>k *amb]2 f ! necessity ( d>k5+ ! room1 9 ord] to exhibit x4 ,! cam]a obscura1 sometimes consi/s ( a small box1 prop]ly fitt$ up1 to repres5t ext]nal objects4 ,?is picture1 y n[ see1 is produc$ by ! rays ( light1 reflect$ f ! v>i\s objects 9 ! g>d51 & :i* are admitt$ ?r\gh ! hole 9 ! w9d[ %utt]4 ,illu/ration3 ,,plate ,,xvi4 ,! rays f ! glitt]+ wea!rcock1 at ! top ( ! alcove1 ,a1 7plate #af47 repres5t x 9 ?is spot1 a2 = ! wea!rcock1 be+ mu* high] ?an ! ap]ture 9 ! %utt]1 only a few ( ! rays1 :i* are reflect$ by x1 9 an obliquely desc5d+ direction1 c f9d entrance !re4 ,! rays ( light1 y "k1 always move 9 /raight l9es2 ^?1 !re=e1 :i* ent] ! room1 9 a desc5d+ direction1 w cont9ue _! c\rse 9 ! same direction1 & w consequ5tly fall ^u ! l[] "p ( ! wall opposite ! ap]ture1 & repres5t ! wea!rcock1 rev]s$ 9 t spot1 in/ead ( erect1 9 ! upp]mo/ "p ( ! l&scape4 ,emily4 ,& ! rays ( light1 f ! /eps1 7,b7 ( ! alcove1 9 ent]+ ! ap]ture1 asc5d1 & w describe ^? /eps 9 ! highe/1 in/ead ( ! l[e/1 "p ( ! l&scape4 ,mrs4 ,b4 ,obs]ve1 too1 t ! rays com+ f ! alcove1 :i* is to our left1 describe x on ! wall1 to ! "r2 :ile ^?1 :i* are reflect$ by ! walnut tree1 ,c ,d1 to our "r1 del9eate its figure 9 ! picture1 to ! left1 c d4 ,?us ! rays1 com+ 9 diff]5t directions1 & proce$+ always 9 "r l9es1 cross ea* o!r at _! entrance ?r\gh ! ap]ture2 ^? :i* come f above1 proce$ bel[1 ^? f ! "r1 g to ! left1 ^? f ! left1 t[>ds ! "r2 ?us e object is repres5t$ 9 ! picture1 z occupy+ a situation1 ! v rev]se ( t :i* x does 9 nature4 ,c>ol9e4 ,except+ ! fl[]-pot1 ,e ,f1 :i*1 ?\gh its position is rev]s$1 has n *ang$ its situation 9 ! l&scape4 ,mrs4 ,b4 ,! fl[]-pot1 is directly 9 front ( ! ap]ture2 s t its rays1 fall p]p5dicul>ly ^u x1 & consequ5tly proce$ p]p5dicul>ly to ! wall1 :]e !y del9eate ! object1 directly beh9d ! ap]ture4 ,emily4 ,& is x ?us1 t ! picture ( objects1 is pa9t$ on ! ret9a ( ! eye8 ,mrs4 ,b4 ,precisely4 ,! pupil ( ! eye1 ?r\gh :i* ! rays ( light ent]1 repres5ts ! ap]ture 9 ! w9d[-%utt]2 & ! image1 del9eat$ on ! ret9a1 is exactly simil> to ! picture on ! wall4 ,c>ol9e4 ,y d n mean to say1 t we see only ! repres5tation ( ! object1 :i* is pa9t$ on ! ret9a1 & n ! object itself8 ,mrs4 ,b4 ,if1 by sight1 y und]/& t s5se1 by :i* ! pres5ce ( objects is p]ceiv$ by ! m9d1 ?r\gh ! means ( ! eyes1 we c]ta9ly see only ! image ( ^? objects1 pa9t$ on ! ret9a4 ,c>ol9e4 ,?is appe>s to me q incr$ible4 ,mrs4 ,b4 ,! n]ves1 are ! only "p ( our frame1 capable ( s5sation3 !y appe>1 !re=e1 to be ! in/rum5ts1 :i* ! m9d employs 9 its p]ceptions2 = a s5sation1 always conveys an idea1 to ! m9d4 ,n[ x is kn[n1 t our n]ves c be affect$ only by contact2 & = ?is reason1 ! organs ( s5se1 _c act at a di/ance3 = in/ance1 we are capable ( smell+ only p>ticles :i* are actually 9 contact ) ! n]ves ( ! nose4 ,we h already obs]v$1 t ! od\r ( a fl[] consi/s 9 effluvia1 compos$ ( v m9ute p>ticles1 :i* p5etrate ! no/rils1 & /rike ^u ! olfactory n]ves1 :i* in/antly convey ! idea ( od\r to ! m9d4 ,emily4 ,& s\nd1 ?\gh x is said to be he>d at a di/ance1 is1 9 fact1 he>d only :5 ! vibrations ( ! air1 :i* convey x to our e>s1 /rike ^u ! auditory n]ve4 ,c>ol9e4 ,!re is no explanation requir$1 to prove t ! s5ses ( feel+ & ( ta/+1 are excit$ only by contact4 ,mrs4 ,b4 ,& ,i hope to conv9ce y1 t ! s5se ( sight1 is s likewise4 ,! n]ves1 :i* con/itute ! s5se ( sight1 are n diff]5t 9 _! nature f ^? ( ! o!r organs2 !y are m]ely in/rum5ts :i* convey ideas to ! m9d1 & c be affect$ only on contact4 ,n[1 s9ce real objects _c be br\ght to t\* ! optic n]ve1 ! image ( !m is convey$ ?i!r by ! rays ( light1 proce$+ f real objects1 :i* actually /rike ^u ! optic n]ve1 & =m t image :i* ! m9d p]ceives4 ,c>ol9e4 ,:ile ,i li/5 to y\r reason+1 ,i feel conv9c$2 b :5 ,i look ^u ! objects ar\nd1 & ?9k t ,i d n see !m1 b m]ely _! image pa9t$ 9 my eyes1 my belief is aga9 /agg]$4 ,i _c reconcile to myself1 ! idea1 t ,i d n really see ?is book :i* ,i hold 9 my h&1 nor ! words :i* ,i read 9 x4 ,mrs4 ,b4 ,did x ev] occur to y z extraord9>y1 t y nev] beheld y\r own face8 ,c>ol9e4 ,no2 because ,i s frequ5tly see an exact repres5tation ( x 9 ! look+-glass4 ,mrs4 ,b4 ,y see a f> m exact repres5tation ( objects on ! ret9a ( y\r eye3 x is a mu* m p]fect mirror1 ?an any made by art4 ,emily4 ,b is x possible1 t ! ext5sive l&scape1 :i* ,i n[ behold f ! w9d[1 %\ld be repres5t$ on s small a space1 z ! ret9a ( ! eye8 ,mrs4 ,b4 ,x w\ld be impossible = art to pa9t s small & di/9ct a m9iature2 b nature works ) a sur] h&1 & a m delicate p5cil4 ,t p[] alone1 :i* =ms ! fea!rs ( ! butt]fly1 & ! organs ( ! m9ute/ insect1 c p\rtray s admirable & p]fect a m9iature1 z t :i* is repres5t$ on ! ret9a ( ! eye4 ,c>ol9e4 ,b1 ,mrs4 ,b41 if we see only ! image ( objects1 :y d we n see !m rev]s$1 z y %[$ u !y 71 9 ! cam]a obscura8 ,is n t a /rong argum5t aga9/ y\r !ory8 ,mrs4 ,b4 ,n an unansw]able "o1 ,i hope4 ,! image on ! ret9a1 x is true1 is rev]s$1 l t 9 ! cam]a obscura2 z ! rays1 f ! diff]5t p>ts ( ! l&scape1 int]sect ea* o!r on ent]+ ! pupil1 9 ! same mann] z !y d1 on ent]+ ! cam]a obscura4 ,! sc5e1 h[ev]1 does n excite ! idea ( be+ inv]t$1 because we always see an object 9 ! direction ( ! rays :i* x s5ds to u4 ,emily4 ,i confess ,i d n und]/& t4 ,mrs4 ,b4 ,x is1 ,i ?9k1 a difficult po9t to expla9 cle>ly4 ,a ray :i* comes f ! upp] "p ( an object1 describes ! image on ! l[] "p ( ! ret9a2 b1 exp]i5ce hav+ taught u1 t ! direction ( t ray is f above1 we consid] t "p ( ! object x repres5ts z upp]mo/4 ,! rays proce$+ f ! l[] "p ( an object1 fall ^u ! upp] "p ( ! ret9a2 b z we "k _! direction to be f bel[1 we see t "p ( ! object !y describe z ! l[e/4 ,c>ol9e4 ,:5 ,i want to see an object above me1 ,i look up2 :5 an object bel[ me1 ,i look d[n4 ,does n ?is prove t ,i see ! objects !mselves8 = if ,i beheld only ! image1 !re w\ld be no necessity = look+ up or d[n1 accord+ z ! object 0 high] or l[]1 ?an myself4 ,mrs4 ,b4 ,i beg y\r p>don4 ,:5 y look up1 to an elevat$ object1 x is 9 ord] t ! rays reflect$ f x1 %\ld fall ^u ! ret9a ( y\r eyes2 b ! v circum/ance ( direct+ y\r eyes upw>ds1 conv9ces y t ! object is elevat$1 & tea*es y to consid] z upp]mo/1 ! image x =ms on ! ret9a1 ?\gh x is1 9 fact1 repres5t$ 9 ! l[e/ "p ( x4 ,:5 y look d[n ^u an object1 y draw y\r conclusion f a simil> reason+2 x is ?us t we see all objects 9 ! direction ( ! rays :i* rea* our eyes4 ,b ,i h a fur!r pro( 9 fav\r ( :at ,i h advanc$1 :i*1 ,i hope1 w remove y\r rema9+ d\bts3 ,i %all1 h[ev]1 def] x till our next meet+1 z ! lesson has be5 suffici5tly long to-day4 ,que/ions #a4 7,pg4 #aeg7 ,:at is optics8 #b4 7,pg4 #aeg7 ,:at is meant by a lum9\s body8 #c4 7,pg4 #aeg7 ,:at is meant by a d>k body1 & :at by an opaque body8 #d4 7,pg4 #aeg7 ,:at are transp>5t bodies8 #e4 7,pg4 #aeg7 ,:at is a m$ium8 #f4 7,pg4 #aeh7 ,h[ is light project$ f lum9\s bodies1 & h[1 f e po9t ( su* bodies1 7fig4 #a1 plate #ae87 #g4 7,pg4 #aeh7 ,:y d n ! rays ( light f diff]5t po9ts1 /op ea* o!r's progress8 #h4 7,pg4 #aeh7 ,:at is a ray1 & :at a p5cil ( rays8 fig4 #b1 plate #ae4 #i4 7,pg4 #aeh7 ,d we "k :e!r light is a sub/ance1 simil> to bodies 9 g5]al8 #aj4 7,pg4 #aeh7 ,:5 a ray ( light falls ^u an opaque body1 :at is ! result8 #aa4 7,pg4 #aei7 ,9 :at does %ad[ consi/8 #ab4 7,pg4 #aei7 ,:y are !y1 9 g5]al1 b p>tially d>k8 #ac4 7,pg4 #aei7 ,^u :at does ! int5sity ( a %ad[ dep5d8 #ad4 7,pg4 #aei7 ,h[ are %ad[s affect$ by ! size ( ! lum9\s body1 z repres5t$ 9 plate #ae1 fig4 #c8 #ae4 7,pg4 #aei7 ,:5 is ! %ad[ l>g] ?an ! int]cept+ body8 #af4 7,pg4 #afj7 ,:at is expla9$ by fig4 #d1 plate #ae8 #ag4 7,pg4 #afj7 ,:at w be ! effect ( sev]al lights1 z 9 fig4 #e1 plate #ae8 #ah4 7,pg4 #afj7 ,:y w nei!r ( ^! %ad[s be v d>k8 #ai4 7,pg4 #afj7 ,:at becomes ( ! light :i* falls ^u an opaque body8 #bj4 7,pg4 #afj7 ,:at is meant by reflection8 #ba4 7,pg4 #afa7 ,:at is meant by ! incid5t1 & reflect$ rays8 #bb4 7,pg4 #afa7 ,:at is ! result1 :5 ! incid5t ray falls p]p5dicul>ly1 & :at1 :5 x falls obliquely8 #bc4 7,pg4 #afa7 ,:at two angles are always equal 9 ?is case8 #bd4 7,pg4 #afa7 ,to :at law 9 me*anics1 is ?is analog\s1 z repres5t$ 9 fig4 #d1 plate #b8 #be4 7,pg4 #afa7 ,:at is repres5t$ by fig4 #f1 plate #ae8 #bf4 7,pg4 #afa7 ,by :at light are we enabl$ to see opaque1 & by :at1 lum9\s bodies8 #bg4 7,pg4 #afa7 ,:at enables u to see a ray ( light 9 its passage1 ?r\gh a d>k5$ room8 #bh4 7,pg4 #afb7 ,by :at reason+ w\ld y prove t an object1 su*1 = example1 z a h\se1 is se5 by reflect$ light8 #bi4 7,pg4 #afb7 ,:y may "o side ( su* object appe> m bright ?an ano!r side8 #cj4 7,pg4 #afb7 ,h[ is ! fact exemplifi$ by ! sun1 or moon1 %9+ ^u wat]8 #ca4 7,pg4 #afb7 ,:y is ?is be/ ev9c$ by moonlight8 #cb4 7,pg4 #afc7 ,by :at light d we see ! moon1 & :y is x comp>atively feeble8 #cc4 7,pg4 #afc7 ,:at circum/ance1 r5d]s objects se5 by moonlight1 /ill less vivid8 #cd4 7,pg4 #afd7 ,:at is meant by ! pupil ( ! eye8 #ce4 7,pg4 #afd7 ,:at by ! ret9a8 #cf4 7,pg4 #afd7 ,h[ d ! rays ( light op]ate on ! eye 9 produc+ vision8 #cg4 7,pg4 #afd7 ,h[ may ?is be exemplifi$1 9 a d>k5$ room8 #ch4 7,pg4 #afd7 ,:at is meant by a cam]a obscura8 #ci4 7,pg4 #afd7 ,h[ is x expla9$ 9 plate #af8 #dj4 7,pg4 #afe7 ,:y are ! objects inv]t$ & rev]s$8 #da4 7,pg4 #afe7 ,:at analogy is !re betwe5 ! cam]a obscura1 & ! eye8 #db4 7,pg4 #afe7 ,is x ! object1 or its picture on ! ret9a1 :i* pres5ts to ! m9d an idea ( ! object se58 #dc4 7,pg4 #aff7 ,by :at organs is s5sation produc$1 & h[ mu/ ^! organs be affect$8 #dd4 7,pg4 #aff7 ,h[ w ! idea ( contact1 apply to objects n t\*+ ! eye8 #de4 7,pg4 #afg7 ,:y d n objects appe> rev]s$ to ! eye1 z 9 ! cam]a obscura8 ,,conv]sation ,,xv4 ,,optics--cont9u$4 ,,on ,,! ,,angle ,,( ,,vision1 ,,& ,,! ,,reflection ,,( ,,mirrors4 ,,angle ,,( ,,vision4 ,,reflection ,,( ,,pla9 ,,mirrors4 ,,reflection ,,( ,,convex ,,mirrors4 ,,reflection ,,( ,,concave ,,mirrors4 ,,c>ol9e4 ,well1 ,mrs4 ,b41 ,i am v impati5t to he> :at fur!r pro(s y h to (f]1 9 support ( y\r !ory4 ,y mu/ all[1 t x 0 r provok+ to dismiss u z y did at our la/ meet+4 ,mrs4 ,b4 ,y press s h>d ^u me ) y\r objections1 t y mu/ give me "t to recruit my =ces4 ,c y tell me1 ,c>ol9e1 :y objects at a di/ance1 appe> small] ?an !y really are8 ,c>ol9e4 ,i "k no o!r reason ?an _! di/ance4 ,mrs4 ,b4 ,x is a fact1 t di/ance causes objects to appe> small]1 b to /ate ! fact1 is n to give ! reason4 ,we mu/ ref] aga9 to ! cam]a obscura1 to acc\nt = ?is circum/ance2 & y w f9d1 t ! diff]5t app>5t dim5sions ( objects at diff]5t di/ances1 proce$ f our see+1 n ! objects !mselves1 b m]ely _! image on ! ret9a4 ,fig4 #a1 plate #ag1 repres5ts a r[ ( trees1 z view$ 9 ! cam]a obscura4 ,i h express$ ! direction ( ! rays1 f ! objects to ! image1 by l9es4 ,n[1 obs]ve1 ! ray :i* comes f ! top ( ! ne>e/ tree1 & t :i* comes f ! foot ( ! same tree1 meet at ! ap]ture1 =m+ an angle ( ab\t tw5ty-five degrees2 ! angle "u :i* we see any object1 is call$1 ! visual angle1 or1 angle ( vision4 ,^! rays cross ea* o!r at ! ap]ture1 =m+ equal angles on ea* side ( x1 & repres5t ! tree inv]t$ 9 ! cam]a obscura4 ,! degrees ( ! image1 are consid]ably small] ?an ^? ( ! object1 b ! proportions are p]fectly pres]v$4 ,illu/ration3 ,,plate ,,xvii4 ,n[1 let u notice ! upp] & l[] ray1 f ! mo/ di/ant tree2 !y =m an angle ( n m ?an twelve or fifte5 degrees1 & an image ( proportional dim5sions4 ,?us1 two objects ( ! same size1 z ! two trees ( ! av5ue1 =m figures ( diff]5t sizes 9 ! cam]a obscura1 accord+ to _! di/ance2 or1 9 o!r words1 accord+ to ! angle ( vision "u :i* !y are se54 ,d y und]/& ?is8 ,c>ol9e4 ,p]fectly4 ,mrs4 ,b4 ,!n y h only to suppose1 t ! repres5tation 9 ! cam]a obscura1 is simil> to t on ! ret9a4 ,n[1 s9ce objects ( ! same magnitudes1 appe> to be ( diff]5t dim5sions1 :5 at diff]5t di/ances f u1 let me ask y :i* x is1 t y see2 ! real objects1 :i*1 we "k1 d n v>y 9 size1 or ! images1 :i*1 we "k1 d v>y1 accord+ to ! angle ( vision "u :i* we see !m8 ,c>ol9e4 ,i mu/ confess1 t reason is 9 fav\r ( ! latt]4 ,b does t *air1 at ! fur!r end ( ! room1 =m an image on my ret9a1 mu* small] ?an ?is :i* is close to me8 !y appe> exactly ( ! same size4 ,mrs4 ,b4 ,our s5ses are imp]fect1 b ! exp]i5ce we acquire by ! s5se ( t\*1 corrects ! illusions ( our sight1 ) reg>d to objects )9 our rea*4 ,y are s p]fectly conv9c$1 ( ! real size ( objects1 :i* y c h&le1 t y d n att5d to ! app>5t diff]5ce4 ,does t h\se appe> to y mu* small]1 ?an :5 y are close to x8 ,c>ol9e4 ,no1 because x is v ne> u4 ,mrs4 ,b4 ,& yet y c see ! :ole ( x1 ?r\gh "o ( ! w9d[s ( ?is room4 ,! image ( ! h\se on y\r ret9a mu/1 !re=e1 be small] ?an t ( ! w9d[ ?r\gh :i* y see x4 ,x is y\r k ( ! real magnitude ( ! h\se :i* prev5ts y\r att5d+ to its app>5t size4 ,if y 7 accu/om$ to draw f nature1 y w\ld be fully aw>e ( ?is diff]5ce4 ,emily4 ,& pray1 :at is ! reason t1 :5 we look up an av5ue1 ! trees n only appe> small] z !y are m di/ant1 b seem gradually to approa* ea* o!r1 till !y meet 9 a po9t8 ,mrs4 ,b4 ,n only ! trees1 b ! road :i* sep>ates ! two r[s1 =ms a small] visual angle1 9 proportion z x is m di/ant f u2 !re=e1 ! wid? ( ! road gradually dim9i%es1 z well z ! size ( ! trees1 till at l5g? ! road app>5tly t]m9ates 9 a po9t1 at :i* ! trees seem to meet4 ,emily4 ,i am v glad to und]/& ?is1 = ,i h lately begun to le>n p]spective1 :i* appe>$ to me a v dry /udy2 b n[ t ,i am acqua9t$ ) "s ( ! pr9ciples on :i* x is f\nd$1 ,i %all f9d x mu* m int]e/+4 ,c>ol9e4 ,9 draw+ a view f nature1 x seems t we d n copy ! real objects1 b ! image !y =m on ! ret9a ( our eyes8 ,mrs4 ,b4 ,c]ta9ly4 ,9 sculpture1 we copy nature z %e really exi/s2 9 pa9t+1 we repres5t h]1 z %e appe>s to u4 ,we mu/ n[ conclude ! obs]vations t rema9 to be made1 on ! angle ( vision4 ,if ! rays1 proce$+ f ! extremities ( an object1 ) an ord9>y degree ( illum9ation1 d n ent] ! eye "u an angle ( m ?an two seconds1 :i* is ! #a-ahjj? "p ( a degree1 x is invisible4 ,!re are1 consequ5tly1 two cases 9 :i* objects may be invisible2 if !y are ei!r s small1 or s di/ant1 z to =m an angle ( less ?an two seconds ( a degree4 ,9 l mann]1 if ! velocity ( a body does n exce$ #bj degrees 9 an h\r1 its motion is imp]ceptible4 ,c>ol9e4 ,a v rapid motion may !n be imp]ceptible1 provid$ ! di/ance ( ! mov+ body1 is suffici5tly great4 ,mrs4 ,b4 ,und\bt$ly2 = ! great] its di/ance1 ! small] w be ! angle1 "u :i* its motion w appe> to ! eye4 ,x is = ?is reason1 t ! motion ( ! cele/ial bodies is invisible1 al?\gh inconceivably rapid4 ,emily4 ,i am surpris$1 t s great a velocity z #bj degrees an h\r1 %\ld be invisible4 ,mrs4 ,b4 ,! real velocity dep5ds ^u ! space compreh5d$ 9 ea* degree1 & ^u ! "t1 9 :i* ! mov+ body1 passes ov] t space4 ,b we c only "k ! ext5t ( ?is space1 by kn[+ ! di/ance ( ! mov+ body1 f its c5tre ( motion2 = suppos+ two m5 to set (f at ! same mom5t f ,a & ,b1 7fig4 #b47 to walk ea* to ! end ( _! respective l9es1 ,c & ,d2 if !y p]=m _! walk 9 ! same space ( "t1 !y mu/ h proce$$ at a v diff]5t rate2 & yet to an eye situat$ at ,e1 !y w appe> to h mov$ ) equal velocity1 because !y w bo? h gone ?r\gh an equal numb] ( degrees1 ?\gh ov] a v unequal l5g? ( gr\nd4 ,! numb] ( degrees ov] :i* a body moves 9 a giv5 "t1 is call$ its angul> velocity2 two bodies1 y see1 may h ! same angul>1 or app>5t velocity1 :il/ _! real velocities may diff] almo/ inf9itely4 ,sight is an extremely useful s5se1 no d\bt1 b x _c always be reli$ on1 x deceives u bo? 9 reg>d to ! size & ! di/ance ( objects2 inde$1 our s5ses w\ld be v liable to lead u into error1 if exp]i5ce did n set u "r4 ,emily4 ,betwe5 ! two1 ,i ?9k t we contrive to acquire a tol]ably accurate idea ( objects4 ,mrs4 ,b4 ,at lea/ suffici5tly s1 = ! g5]al purposes ( life4 ,to conv9ce y h[ requisite exp]i5ce is1 to correct ! errors ( sight1 ,i %all relate to y1 ! case ( a "y man1 :o 0 bl9d f 8 infancy1 & :o recov]$ 8 sight at ! age ( f\rte51 by ! op]ation ( c\*+4 ,at fir/1 he _h no idea1 ei!r ( ! size1 or di/ance ( objects1 b imag9$ t e ?+ he saw t\*$ 8 eyes2 & x 0 n1 till aft] hav+ repeat$ly felt !m1 & walk$ f "o object to ano!r1 t he acquir$ an idea ( _! respective dim5sions1 _! relative situations1 & _! di/ances4 ,c>ol9e4 ,! idea t objects t\*$ 8 eyes1 is1 h[ev]1 n s absurd1 z x at fir/ appe>s2 = if we consid] t we see only ! image ( objects1 ?is image actually t\*es our eyes4 ,mrs4 ,b4 ,t is1 d\btless1 ! reason ( ! op9ion he =m$1 be=e ! s5se ( t\* _h correct$ 8 judgm5t4 ,c>ol9e4 ,b s9ce an image mu/ be =m$ on ! ret9a ( ea* ( our eyes1 :y d we n see objects d\ble8 ,mrs4 ,b4 ,! action ( ! rays1 on ! optic n]ve ( ea* eye1 is s p]fectly simil>1 t !y produce b a s+le s5sation2 ! m9d1 !re=e1 receives ! same idea1 f ! ret9a ( bo? eyes1 & conceives ! object to be s+le4 ,c>ol9e4 ,?is is difficult to compreh5d1 & ,i %\ld ?9k1 c be b conjectural4 ,mrs4 ,b4 ,i c easily conv9ce y1 t y h a di/9ct image ( an object =m$ on ! ret9a ( ea* eye4 ,look ?r\gh ! w9d[1 ) bo? eyes op51 at "s object exactly opposite to "o ( ! upright b>s ( ! sa%4 ,c>ol9e4 ,i n[ see a tree1 ! body ( :i*1 appe>s to be 9 a l9e exactly opposite to "o ( ! b>s4 ,mrs4 ,b4 ,if y n[ %ut y\r "r eye1 & look ) ! left1 x w appe> to ! left ( ! b>2 !n by clos+ ! left eye1 & look+ ) ! o!r1 x w appe> to ! "r ( ! b>4 ,c>ol9e4 ,t is true1 inde$6 ,mrs4 ,b4 ,!re are1 evid5tly1 two repres5tations ( ! tree 9 diff]5t situations1 :i* mu/ be ow+ to an image ( x be+ =m$ on ea* eye2 if ! action ( ! rays1 !re=e1 on ea* ret9a1 7 n s p]fectly simil> z to produce b "o s5sation1 we %\ld see d\ble2 & we f9d t to be ! case ) "s p]sons1 :o are afflict$ ) a disease 9 "o eye1 :i* prev5ts ! rays ( light f affect+ x 9 ! same mann] z ! o!r4 ,emily4 ,pray1 ,mrs4 ,b41 :5 we see ! image ( an object 9 a look+-glass1 :y is x n inv]t$1 z 9 ! cam]a obscura1 & on ! ret9a ( ! eye8 ,mrs4 ,b4 ,because ! rays d n ent] ! mirror by a small ap]ture1 & cross ea* o!r1 z !y d at ! orifice ( a cam]a obscura1 or ! pupil ( ! eye4 ,:5 y view y\rself 9 a mirror1 ! rays f y\r eyes fall p]p5dicul>ly ^u x1 & are reflect$ 9 ! same l9e2 ! image is1 !re=e1 describ$ beh9d ! glass1 & is situat$ 9 ! same mann] z ! object be=e x4 ,emily4 ,yes1 ,i see t x is2 b ! look+-glass is n ne>ly s tall z ,i am1 h[ is x1 !re=e1 t ,i c see ! :ole ( my figure 9 x8 ,mrs4 ,b4 ,x is n necess>y t ! mirror %\ld be m ?an half y\r height1 9 ord] t y may see ! :ole ( y\r p]son 9 x1 7fig4 #c47 ,! ray ( light ,a ,b1 f y\r eye1 :i* falls p]p5dicul>ly on ! mirror ,b ,d1 w be reflect$ back1 9 ! same l9e2 b ! ray f y\r feet1 w fall obliquely on ! mirror1 = x mu/ asc5d 9 ord] to rea* x2 x w1 !re=e1 be reflect$ 9 ! l9e ,a ,d3 & s9ce we view objects 9 ! direction ( ! reflect$ rays1 :i* rea* ! eye1 & s9ce ! image appe>s at ! same di/ance1 beh9d ! mirror1 t ! object is be=e x1 we mu/ cont9ue ! l9e ,a ,d to ,e1 & ! l9e ,c ,d to ,f1 at ! t]m9ation ( :i*1 ! image w be repres5t$4 ,illu/ration3 ,,plate ,,xviii4 ,emily4 ,!n ,i d n und]/& :y ,i %\ld n see ! :ole ( my p]son 9 a mu* small] mirror1 = a ray ( light f my feet w\ld always rea* x1 ?\gh m obliquely4 ,mrs4 ,b4 ,true2 b ! m obliquely ! ray falls on ! mirror1 ! m obliquely x w be reflect$2 ! ray w\ld1 !re=e1 be reflect$ above y\r head1 & y c\ld n see x4 ,?is is %[n by ! dott$ l9e 7fig4 #c47 ,n[ /& a little to ! "r ( ! mirror1 s t ! rays ( light f y\r figure may fall obliquely on x---- ,emily4 ,!re is no image =m$ ( me 9 ! glass n[4 ,mrs4 ,b4 ,i beg y\r p>don1 !re is2 b y _c see x1 because ! incid5t rays1 fall+ obliquely on ! mirror1 w be reflect$ obliquely1 9 ! opposite direction2 ! angles ( incid5ce1 & reflection1 be+ equal4 ,c>ol9e1 place y\rself 9 ! direction ( ! reflect$ rays1 & tell me :e!r y d n see ,emily's image 9 ! glass8 ,c>ol9e4 ,let me consid]4--,9 ord] to look 9 ! direction ( ! reflect$ rays1 ,i mu/ place myself z mu* to ! left ( ! glass1 z ,emily /&s to ! "r ( x4--,n[ ,i see h] image1 n /raight be=e me1 h[ev]1 b be=e h]2 & x appe>s at ! same di/ance beh9d ! glass1 t %e is 9 front ( x4 ,mrs4 ,b4 ,y mu/ recollect1 t we always see objects 9 ! direction ( ! la/ rays1 :i* rea* our eyes4 ,figure #d repres5ts an eye1 look+ at ! image ( a vase1 reflect$ by a mirror2 x mu/ see x 9 ! direction ( ! ray ,a ,b1 z t is ! ray :i* br+s ! image to ! eye2 prolong ! ray to ,c1 & 9 t spot w ! image appe>4 ,c>ol9e4 ,i d n und]/& :y a look+-glass reflects ! rays ( light2 = glass is a transp>5t body1 :i* %\ld transmit !m6 ,mrs4 ,b4 ,x is n ! glass t reflects ! rays :i* =m ! image y behold1 b ! silv]+ beh9d x2 ?is silv]+ is a comp\nd ( m]cury & t91 :i* =ms a brilliant metallic coat+4 ,! glass acts *iefly z a transp>5t case1 ?r\gh :i* ! rays f9d an easy passage1 to1 & f1 ! quicksilv]4 ,c>ol9e4 ,:y !n %\ld n mirrors be made simply ( m]cury8 ,mrs4 ,b4 ,because m]cury is a fluid4 ,by amalgamat+ x ) t9foil1 x becomes ( ! consi/5ce ( pa/e1 atta*es itself to ! glass1 & =ms1 9 fact1 a metallic mirror1 :i* w\ld be mu* m p]fect )\t its glass cov]1 = ! pure/ glass is nev] p]fectly transp>5t2 "s ( ! rays1 !re=e1 are lo/ dur+ _! passage ?r\gh x1 by be+ ei!r absorb$1 or irregul>ly reflect$4 ,?is imp]fection ( glass mirrors1 has introduc$ ! use ( metallic mirrors1 = optical purposes4 ,emily4 ,b s9ce all opaque bodies reflect ! rays ( light1 ,i d n und]/& :y !y are n all mirrors4 ,c>ol9e4 ,a curi\s idea inde$1 si/]2 x w\ld be v gratify+ to see oneself 9 e object at :i* "o look$4 ,mrs4 ,b4 ,x is v true t all opaque objects reflect light2 b ! surface ( bodies1 9 g5]al1 is s r\gh & unev51 t ! reflection f !m is extremely irregul>1 & prev5ts ! rays f =m+ an image on ! ret9a4 ,?is1 y w be able to und]/& bett]1 :5 ,i %all expla9 to y ! nature ( vision1 & ! /ructure ( ! eye4 ,y may easily conceive ! v>iety ( directions 9 :i* rays w\ld be reflect$ by a nutmeg-grat]1 on acc\nt ( ! inequality ( its surface1 & ! numb] ( holes ) :i* x is pi]c$4 ,all solid bodies m or less resemble ! nutmeg-grat]1 9 ^! respects2 & x is only ^? :i* are susceptible ( receiv+ a poli%1 t c be made to reflect ! rays ) regul>ity4 ,z h>d bodies are ( ! close/ texture1 ! lea/ por\s1 & capable ( tak+ ! highe/ poli%1 !y make ! be/ mirrors2 none1 !re=e1 are s well calculat$ = ?is purpose1 z metals4 ,c>ol9e4 ,b ! prop]ty ( regul> reflection1 is n conf9$ to ?is class ( bodies2 = ,i h (t5 se5 myself1 9 a highly poli%$ mahogany table4 ,mrs4 ,b4 ,c]ta9ly2 b z t sub/ance is less durable1 & its reflection less p]fect1 ?an t ( metals1 ,i believe x w\ld seldom be *os51 = ! purpose ( a mirror4 ,!re are ?ree k9ds ( mirrors us$ 9 optics2 ! pla91 or flat1 :i* are ! common mirrors we h j m5tion$2 convex mirrors1 & concave mirrors4 ,! reflection ( ! two latt]1 is v diff]5t f t ( ! =m]4 ,! pla9 mirror1 we h se51 does n alt] ! direction ( ! reflect$ rays1 & =ms an image beh9d ! glass1 exactly simil> to ! object be=e x4 ,a convex mirror has ! peculi> prop]ty ( mak+ ! reflect$ rays div]ge1 by :i* means x dim9i%es ! image2 & a concave mirror makes ! rays conv]ge1 & "u c]ta9 circum/ances1 magnifies ! image4 ,emily4 ,we h a convex mirror 9 ! draw+-room1 :i* =ms a beautiful m9iature picture ( ! objects 9 ! room2 & ,i h (t5 amus$ myself ) look+ at my magnifi$ face 9 a concave mirror4 ,b ,i hope y w expla9 to u1 :y ! "o enl>ges1 :ile ! o!r dim9i%es ! objects x reflects4 ,mrs4 ,b4 ,let u beg9 by exam9+ ! reflection ( a convex mirror4 ,?is is =m$ ( a portion ( ! ext]ior surface ( a sph]e4 ,:5 sev]al p>allel rays fall ^u x1 t ray only :i*1 if prolong$1 w\ld pass ?r\gh ! c5tre or axis ( ! mirror1 is p]p5dicul> to x4 ,9 ord] to avoid confusion1 ,i h1 9 fig4 #a1 plate #ah1 drawn only ?ree p>allel l9es1 ,a ,b1 ,c ,d1 ,e ,f1 to repres5t rays fall+ on ! convex mirror1 ,m ,n2 ! middle ray1 y w obs]ve1 is p]p5dicul> to ! mirror1 ! o!rs fall on x1 obliquely4 ,c>ol9e4 ,z ! ?ree rays are p>allel1 :y are !y n all p]p5dicul> to ! mirror8 ,mrs4 ,b4 ,!y w\ld be s to a flat mirror2 b z ?is is sph]ical1 no ray c fall p]p5dicul>ly ^u x :i* is n direct$ t[>ds ! c5tre ( ! sph]e4 ,emily4 ,j z a weight falls p]p5dicul>ly to ! e>?1 :5 gravity attracts x t[>ds ! c5tre4 ,mrs4 ,b4 ,9 ord]1 !re=e1 t rays may fall p]p5dicul>ly to ! mirror at ,b & ,f1 ! rays mu/ be 9 ! direction ( ! dott$ l9es1 :i*1 y may obs]ve1 meet at ! c5tre ,o ( ! sph]e1 ( :i* ! mirror =ms a portion4 ,n[1 c y tell me 9 :at direction ! ?ree rays1 ,a ,b1 ,c ,d1 ,e ,f1 w be reflect$8 ,emily4 ,yes1 ,i ?9k s3 ! middle ray1 fall+ p]p5dicul>ly on ! mirror1 w be reflect$ 9 ! same l9e3 ! two out] rays fall+ obliquely1 w be reflect$ obliquely to ,g & ,h2 = ! dott$ l9es y h drawn are p]p5dicul>s1 :i* divide ! angles ( incid5ce & reflection1 ( ^? two rays4 ,mrs4 ,b4 ,extremely well1 ,emily3 & s9ce we see objects 9 ! direction ( ! reflect$ ray1 we %all see ! image ,l1 :i* is ! po9t at :i* ! reflect$ rays1 if cont9u$ ?r\gh ! mirror1 w\ld unite & =m an image4 ,?is po9t is equally di/ant1 f ! surface & c5tre ( ! sph]e1 & is call$ ! imag9>y focus ( ! mirror4 ,c>ol9e4 ,pray1 :at is ! mean+ ( focus8 ,mrs4 ,b4 ,a po9t at :i* conv]g+ rays1 unite4 ,& x is 9 ?is case1 call$ an imag9>y focus2 because ! rays d n really unite at t po9t1 b only appe> to d s3 = ! rays d n pass ?r\gh ! mirror1 s9ce !y are reflect$ by x4 ,emily4 ,i d n yet und]/& :y an object appe>s small]1 :5 view$ 9 a convex mirror4 ,mrs4 ,b4 ,x is ow+ to ! div]g5ce ( ! reflect$ rays4 ,y h se5 t a convex mirror1 by reflection1 conv]ts p>allel rays into div]g5t rays2 rays t fall ^u ! mirror div]g5t1 are r5d]$ /ill m s by reflection1 & conv]g5t rays are reflect$ ei!r p>allel1 or less conv]g5t4 ,if !n1 an object be plac$ be=e any "p ( a convex mirror1 z ! vase ,a ,b1 fig4 #b1 = in/ance1 ! two rays f its extremities1 fall+ conv]g5t on ! mirror1 w be reflect$ less conv]g5t1 & w n come to a focus1 till !y arrive at ,c2 !n an eye plac$ 9 ! direction ( ! reflect$ rays1 w see ! image =m$ 9 7or r beh9d7 ! mirror1 at a b4 ,c>ol9e4 ,b ! reflect$ rays1 d n appe> to me to conv]ge less ?an ! incid5t rays4 ,i %\ld h suppos$ t1 on ! contr>y1 !y conv]g$ m1 s9ce !y meet 9 a po9t4 ,mrs4 ,b4 ,!y w\ld unite soon] ?an !y actually d1 if !y 7 n less conv]g5t ?an ! incid5t rays3 = obs]ve1 t if ! incid5t rays1 in/ead ( be+ reflect$ by ! mirror1 cont9u$ _! c\rse 9 _! orig9al direction1 !y w\ld come to a focus at ,d1 :i* is consid]ably ne>] to ! mirror ?an at ,c2 ! image1 is1 !re=e1 se5 "u a small] angle ?an ! object2 & ! m di/ant ! latt] is f ! mirror1 ! small] is ! image reflect$ by x4 ,y w n[ easily und]/& ! nature ( ! reflection ( concave mirrors4 ,^! are =m$ ( a portion ( ! int]nal surface ( a holl[ sph]e1 & _! peculi> prop]ty is to conv]ge ! rays ( light4 ,c y discov]1 ,c>ol9e1 9 :at direction ! ?ree p>allel rays1 ,a ,b1 ,c ,d1 ,e ,f1 are reflect$1 :i* fall on ! concave mirror1 ,m ,n1 7fig4 #c478 ,c>ol9e4 ,i believe ,i c4 ,! middle ray is s5t back 9 ! same l9e1 9 :i* x arrives1 t be+ ! direction ( ! axis ( ! mirror2 & ! two o!rs w be reflect$ obliquely1 z !y fall obliquely on ! mirror4 ,i mu/ n[ draw two dott$ l9es p]p5dicul> to _! po9ts ( incid5ce1 :i* w divide _! angles ( incid5ce & reflection2 & 9 ord] t ^? angles may be equal1 ! two oblique rays mu/ be reflect$ to ,l1 :]e !y w unite ) ! middle ray4 ,mrs4 ,b4 ,v well expla9$4 ,?us y see1 t :5 any numb] ( p>allel rays fall on a concave mirror1 !y are all reflect$ to a focus3 = 9 proportion z ! rays are m di/ant f ! axis ( ! mirror1 !y fall m obliquely ^u x1 & are m obliquely reflect$2 9 consequ5ce ( :i* !y come to a focus 9 ! direction ( ! axis ( ! mirror1 at a po9t equally di/ant f ! c5tre1 & ! surface1 ( ! sph]e2 & ?is po9t is n an imag9>y focus1 z happ5s ) ! convex mirror1 b is ! true focus at :i* ! rays unite4 ,emily4 ,c a mirror =m m ?an "o focus1 by reflect+ rays8 ,mrs4 ,b4 ,yes4 ,if rays fall conv]g5t on a concave mirror1 7fig4 #d17 !y are soon] br\ght to a focus1 ,l1 ?an p>allel rays2 _! focus is1 !re=e1 ne>] to ! mirror ,m ,n4 ,div]g5t rays are br\ght to a m di/ant focus ?an p>allel rays1 z 9 figure #e1 :]e ! focus is at ,l2 b :at is call$ ! true focus ( mirrors1 ei!r convex or concave1 is t ( p>allel rays1 & is equally di/ant f ! c5tre1 & ! surface ( ! sph]ical mirror4 ,i %all n[ %[ y ! real reflection ( rays ( light1 by a metallic concave mirror4 ,?is is "o made ( poli%$ t91 :i* ,i expose to ! sun1 & z x %9es bright1 we %all be able to collect ! rays into a v brilliant focus4 ,i hold a piece ( pap] :]e ,i imag9e ! focus to be situat$2 y may see by ! vivid spot ( light on ! pap]1 h[ mu* ! rays conv]ge3 b x is n yet exactly 9 ! focus2 z ,i approa* ! pap] to t po9t1 obs]ve h[ ! brightness ( ! spot ( light increases1 :ile its size dim9i%es4 ,c>ol9e4 ,t mu/ be occasion$ by ! rays approa*+ clos] toge!r4 ,i ?9k y hold ! pap] j 9 ! focus n[1 ! light is s small & dazzl+--,oh1 ,mrs4 ,b41 ! pap] has tak5 fire6 ,mrs4 ,b4 ,! rays ( light _c be conc5trat$1 )\t1 at ! same "t1 accumulat+ a proportional quantity ( heat3 h5ce concave mirrors h obta9$ ! "n ( burn+ mirrors4 ,emily4 ,i h (t5 he>d ( ! surpris+ effects ( burn+ mirrors1 & ,i am q delight$ to und]/& _! nature4 ,c>ol9e4 ,x _c be ! true focus ( ! mirror1 at :i* ! rays ( ! sun unite1 = z !y proce$ f s l>ge a body1 !y _c fall ^u ! mirror p>allel to ea* o!r4 ,mrs4 ,b4 ,/rictly speak+1 !y c]ta9ly d n4 ,b :5 rays1 come f su* an imm5se di/ance z ! sun1 !y may be consid]$ z p>allel3 _! po9t ( union is1 !re=e1 ! true focus ( ! mirror1 & !re ! image ( ! object is repres5t$4 ,n[ t ,i h remov$ ! mirror out ( ! influ5ce ( ! sun's rays1 if ,i place a burn+ tap] 9 ! focus1 h[ w its light be reflect$8 7,fig4 #f47 ,c>ol9e4 ,t1 ,i confess1 ,i _c say4 ,mrs4 ,b4 ,! ray :i* falls 9 ! direction ( ! axis ( ! mirror1 is reflect$ back 9 ! same l9e2 b let u draw two o!r rays f ! focus1 fall+ on ! mirror at ,b & ,f2 ! dott$ l9es are p]p5dicul> to ^? po9ts1 & ! two rays w1 !re=e1 be reflect$ to ,a & ,e4 ,c>ol9e4 ,oh1 n[ ,i und]/& x cle>ly4 ,! rays :i* proce$ f a light plac$ 9 ! focus ( a concave mirror fall div]g5t ^u x1 & are reflect$1 p>allel4 ,x is exactly ! rev]se ( ! =m] exp]im5t1 9 :i* ! sun's rays fell p>allel on ! mirror1 & 7 reflect$ to a focus4 ,mrs4 ,b4 ,yes3 :5 ! incid5t rays are p>allel1 ! reflect$ rays conv]ge to a focus2 :51 on ! contr>y1 ! incid5t rays proce$ f ! focus1 !y are reflect$ p>allel4 ,?is is an important law ( optics1 & s9ce y are n[ acqua9t$ ) ! pr9ciples on :i* x is f\nd$1 ,i hope t y w n =get x4 ,c>ol9e4 ,i am sure t we %all n4 ,b1 ,mrs4 ,b41 y said t ! image 0 =m$ 9 ! focus ( a concave mirror2 yet ,i h frequ5tly se5 glass concave mirrors1 :]e ! object has be5 repres5t$ )9 ! mirror1 9 ! same mann] z 9 a convex mirror4 ,mrs4 ,b4 ,t is ! case only1 :5 ! object is plac$ betwe5 ! mirror & its focus2 ! image !n appe>s magnifi$ beh9d ! mirror1 or1 z y w\ld say1 )9 x4 ,c>ol9e4 ,i d n und]/& :y ! image %\ld be l>g] ?an ! object4 ,mrs4 ,b4 ,?is results f ! conv]g5t prop]ty ( ! concave mirror4 ,if an object1 ,a ,b1 7fig4 #g47 be plac$ betwe5 ! mirror & its focus1 ! rays f its extremities fall div]g5t on ! mirror1 & on be+ reflect$1 become less div]g5t1 z if !y proce$$ f ,c3 to an eye plac$ 9 t situation1 ! image w appe> magnifi$ beh9d ! mirror at a b1 s9ce x is se5 "u a l>g] angle ?an ! object4 ,y n[1 ,i hope1 und]/& ! reflection ( light by opaque bodies4 ,at our next meet+1 we %all ent] ^u ano!r prop]ty ( light1 no less int]e/+1 & :i* is call$ refraction4 ,que/ions #a4 7,pg4 #afh7 ,:at is meant by ! angle ( vision1 or ! visual angle8 #b4 7,pg4 #afi7 ,:y d objects ( ! same size appe> small] :5 di/ant1 ?an :5 ne>8 #c4 7,pg4 #afi7 ,:y d n two objects1 kn[n to be equal 9 size1 appe> to diff]1 :5 at diff]5t di/ances f ! eye8 #d4 7,pg4 #afi7 ,h[ is ?is exemplifi$1 by a h\se se5 ?r\gh a w9d[8 #e4 7,pg4 #agj7 ,:y d r[s ( trees1 =m+ an av5ue1 appe> to approa* z !y rec$e f ! eye1 until !y ev5tually seem to meet8 #f4 7,pg4 #agj7 ,9 draw+ a view f nature1 :at d we copy8 #g4 7,pg4 #agj7 ,:at is ! diff]5ce 9 sculpture1 9 ?is respect8 #h4 7,pg4 #agj7 ,except+ ! rays f an object ent] ! eye1 "u a c]ta9 angle1 !y _c be se52 :at mu/ ?is angle exce$8 #i4 7,pg4 #agj7 ,:at two circum/ances may cause ! angle to be s small1 z n to produce vision8 #aj4 7,pg4 #agj7 ,motion may be s sl[ z to become imp]ceptible1 :at is said on ?is po9t8 #aa4 7,pg4 #agj7 ,"u :at circum/ances may a body1 mov+ ) great rapidity1 appe> to be at re/8 #ab4 7,pg4 #agj7 ,^u :at does ! real velocity ( a body1 dep5d8 #ac4 7,pg4 #aga7 ,:at mu/ be kn[n1 to enable u to asc]ta9 ! real space conta9$ 9 a degree8 #ad4 7,pg4 #aga7 ,:at is expla9$ by fig4 #b1 plate #ag8 #ae4 7,pg4 #aga7 ,:at is said respect+ ! evid5ce af=d$ by our s5ses1 & h[ d we correct ! errors into :i* !y w\ld lead u8 #af4 7,pg4 #aga7 ,an image ( a visible object is =m$ ^u ! ret9a ( ea* eye1 :y1 !re=e1 are n objects se5 d\ble8 #ag4 7,pg4 #agb7 ,by :at exp]im5t c y prove t a sep>ate image ( an object is =m$ 9 ea* eye8 #ah4 7,pg4 #agb7 ,"u :at circum/ances are objects se5 d\ble8 #ai4 7,pg4 #agb7 ,:y is n ! image ( an object inv]t$ 9 ! common mirror8 #bj4 7,pg4 #agb7 ,y\r :ole figure may be se5 9 a look+-glass1 :i* is n m ?an half y\r height2 h[ is ?is %[n 9 fig4 #c4 plate #ag8 #ba4 7,pg4 #agc7 ,:y is ! image invisible to ! p]son1 :5 n /&+ directly be=e ! glass8 #bb4 7,pg4 #agc7 ,9 :at situation may a second p]son see ! image reflect$8 #bc4 7,pg4 #agc7 ,9 :at direction w an object always appe> to ! eye8 #bd4 7,pg4 #agc7 ,h[ is ?is expla9$ by fig4 #d1 plate #ag8 #be4 7,pg4 #agc7 ,:at is x t reflects ! rays 9 a look+-glass8 #bf4 7,pg4 #agd7 ,all opaque bodies reflect "s light1 :y d !y n all act z mirrors8 #bg4 7,pg4 #agd7 ,:at sub/ances =m ! mo/ p]fect mirrors1 & = :at reason8 #bh4 7,pg4 #agd7 ,:at are ! ?ree k9ds ( mirrors usually employ$ = optical purposes8 #bi4 7,pg4 #agd7 ,h[ are ! rays ( light affect$ by !m8 #cj4 7,pg4 #age7 ,:at is ! =m ( a convex mirror1 & h[ d p>allel rays fall ^u x1 z repres5t$ 9 fig4 #a1 plate #ah8 #ca4 7,pg4 #age7 ,:at is repres5t$ by ! dott$ l9e 9 ! same figure8 #cb4 7,pg4 #age7 ,expla9 by ! figure1 h[ ! p>allel rays w be reflect$4 #cc4 7,pg4 #age7 ,at :at di/ance beh9d su* a mirror1 w\ld an image1 produc$ by p>allel rays1 be =m$8 #cd4 7,pg4 #age7 ,:at is t po9t d5om9at$8 #ce4 7,pg4 #agf7 ,:at is meant by a focus8 #cf4 7,pg4 #agf7 ,:y is ! po9t beh9d ! mirror1 call$ ! imag9>y focus8 #cg4 7,pg4 #agf7 ,:y does an object appe> to be less5$ by a convex mirror1 7fig4 #b478 #ch4 7,pg4 #agf7 ,:at is a concave mirror1 & :at its peculi> prop]ty8 #ci4 7,pg4 #agf7 ,h[ are p>allel rays reflect$ by a concave mirror1 z expla9$ by fig4 #c1 plate #ah8 #dj4 7,pg4 #agg7 ,:]e is ! focus ( p>allel rays1 9 a concave mirror8 #da4 7,pg4 #agg7 ,if rays fall on x conv]g5t1 h[ are !y reflect$8 #db4 7,pg4 #agg7 ,h[ if div]g5t8 #dc4 7,pg4 #agg7 ,h[1 & :y1 may concave1 become burn+ mirrors8 #dd4 7,pg4 #agh7 ,:y may rays ( light com+ f ! sun1 be view$ z p>allel to ea* o!r8 #de4 7,pg4 #agh7 ,if a lum9\s body1 z a burn+ tap]1 be plac$ 9 ! focus ( a concave mirror1 h[ w ! rays f x1 be reflect$8 7fig4 #f47 #df4 7,pg4 #agh7 ,:at fact is expla9$ by fig4 #g1 plate #ah8 ,,conv]sation ,,xvi4 ,,on ,,refraction ,,& ,,col\rs4 ,,transmission ,,( ,,light ,,by ,,transp>5t ,,bodies4 ,,refraction4 ,,refraction ,,by ,,! ,,atmosph]e4 ,,refraction ,,by ,a ,,l5s4 ,,refraction ,,by ,,! ,,prism4 ,,( ,,col\r ,,f ,,! ,,rays ,,( ,,light4 ,,( ,,! ,,col\rs ,,( ,,bodies4 ,,mrs4 ,b4 ,! refraction ( light w furni% ! subject ( to-day's lesson4 ,c>ol9e4 ,t is a prop]ty ( :i* ,i h n ! fa9te/ idea4 ,mrs4 ,b4 ,x is ! effect :i* transp>5t m$iums produce on light 9 its passage ?r\gh !m4 ,opaque bodies1 y "k1 reflect ! rays1 & transp>5t bodies transmit !m2 b x is f\nd1 t if a ray1 9 pass+ f "o m$ium1 into ano!r ( diff]5t d5sity1 fall obliquely1 x is turn$ out ( its c\rse4 ,! ray ( light is !n said to be refract$4 ,c>ol9e4 ,x mu/ !n be act$ on by "s new p[]1 o!rwise x w\ld n deviate f its fir/ direction4 ,mrs4 ,b4 ,! p[] :i* causes ! deviation ( ! ray1 appe>s to be ! attraction ( ! d5s] m$ium4 ,let u suppose ! two m$iums to be air1 & wat]2 if a ray ( light passes f air1 into wat]1 x is m /rongly attract$ by ! latt]1 on acc\nt ( its sup]ior d5sity4 ,emily4 ,9 :at direction does ! wat] attract ! ray8 ,mrs4 ,b4 ,! ray is attract$ p]p5dicul>ly t[>ds ! wat]1 9 ! same mann] 9 :i* bodies are act$ ^u by gravity4 ,if !n a ray1 ,a ,b1 7fig4 #a1 plate #ai47 fall p]p5dicul>ly on wat]1 ! attraction ( ! wat] acts 9 ! same direction z ! c\rse ( ! ray3 x w n1 !re=e1 cause a deviation1 & ! ray w proce$ /raight on1 to ,e4 ,b if x fall obliquely1 z ! ray ,c ,b1 ! wat] w attract x out ( its c\rse4 ,let u suppose ! ray to h approa*$ ! surface ( a d5s] m$ium1 & t x !re beg9s to be affect$ by its attraction2 ?is attraction1 if n c\nt]act$ by "s o!r p[]1 w\ld draw x p]p5dicul>ly to ! wat]1 at ,b2 b x is also impell$ by its projectile =ce1 :i* ! attraction ( ! d5s] m$ium _c ov]come2 ! ray1 !re=e1 act$ on by bo? ^! p[]s1 moves 9 a direction betwe5 !m1 & in/ead ( pursu+ its orig9al c\rse to ,d1 or be+ implicitly guid$ by ! wat] to ,e1 proce$s t[>ds ,f1 s t ! ray appe>s b5t or brok54 ,c>ol9e4 ,i und]/& t v well2 & is n ?is ! reason t o>s appe> b5t 9 ! wat]8 ,mrs4 ,b4 ,x is ow+ to ! refraction ( ! rays1 reflect$ by ! o>2 b ?is is 9 pass+ f a d5se1 to a r>e m$ium1 = y "k t ! rays1 by means ( :i* y see ! o>1 pass f wat] into air4 ,emily4 ,b ,i d n und]/& :y refraction takes place1 :5 a ray passes f a d5se into a r>e m$ium2 ,i %\ld suppose t x w\ld be less1 attract$ by ! latt]1 ?an by ! =m]4 ,mrs4 ,b4 ,& x is precisely on t acc\nt t ! ray is refract$4 ,let ! upp] half ( fig4 #b1 repres5t glass1 & ! l[] half wat]1 let ,c ,b repres5t a ray1 pass+ obliquely f ! glass1 into wat]3 glass1 be+ ! d5s] m$ium1 ! ray w be m /rongly attract$ by t :i* x leaves ?an by t :i* x ent]s4 ,! attraction ( ! glass acts 9 ! direction ,a ,b1 :ile ! impulse ( projection w\ld c>ry ! ray to ,f2 x moves1 !re=e1 betwe5 ^! directions t[>ds ,d4 ,emily4 ,s t a contr>y refraction takes place1 :5 a ray passes f a d5se1 into a r>e m$ium4 ,illu/ration3 ,,plate ,,xix4 ,mrs4 ,b4 ,! rule ^u ?is subject is ?is2 :5 a ray ( light passes f a r>e into a d5se m$ium1 x is refract$ t[>ds ! p]p5dicul>2 :5 f a d5se into a r>e m$ium1 x is refract$ f ! p]p5dicul>4 ,by ! p]p5dicul> is meant a l9e1 at "r angle ) ! refract+ surface4 ,?is may be se5 9 fig4 #a1 & fig4 #b1 :]e ! l9es ,a ,e1 are ! p]p5dicul>s4 ,c>ol9e4 ,b does n ! attraction ( ! d5s] m$ium affect ! ray be=e x t\*es x8 ,mrs4 ,b4 ,! di/ance at :i* ! attraction ( ! d5s] m$ium acts ^u a ray1 is s small1 z to be ins5sible2 x appe>s1 !re=e1 to be refract$ only at ! po9t at :i* x passes f "o m$ium into ! o!r4 ,n[ t y und]/& ! pr9ciple ( refraction1 ,i w %[ y ! real refraction ( a ray ( light4 ,d y see ! fl[] pa9t$ at ! bottom ( ! inside ( ?is tea-cup8 7,fig4 #c47 ,emily4 ,yes4--,b n[ y h mov$ x j out ( sight2 ! rim ( ! cup hides x4 ,mrs4 ,b4 ,d n /ir4 ,i w fill ! cup ) wat]1 & y w see ! fl[] aga94 ,emily4 ,i d1 inde$6 ,let me try to expla9 ?is3 :5 y drew ! cup f me1 s z to conceal ! fl[]1 ! rays reflect$ by x1 no long] met my eyes1 b 7 direct$ above !m2 b n[ t y h fill$ ! cup ) wat]1 !y are refract$1 & b5t d[nw>ds :5 pass+ out ( ! wat]1 into ! air1 s z aga9 to ent] my eyes4 ,mrs4 ,b4 ,y h expla9$ x p]fectly3 fig4 #c4 w help to impr9t x on y\r memory4 ,y mu/ obs]ve t :5 ! fl[] becomes visible by ! refraction ( ! ray1 y d n see x 9 ! situation :i* x really occupies1 b ! image ( ! fl[] appe>s high] 9 ! cup2 = z objects always appe> to be situat$ 9 ! direction ( ! rays :i* ent] ! eye1 ! fl[] w be se5 at ,b1 9 ! direction ( ! refract$ ray4 ,emily4 ,!n1 :5 we see ! bottom ( a cle> /ream ( wat]1 ! rays :i* x reflects1 be+ refract$ 9 _! passage f ! wat] into ! air1 w make ! bottom appe> high] ?an x really is4 ,mrs4 ,b4 ,& ! wat] w consequ5tly appe> m %all[4 ,accid5ts h frequ5tly be5 occasion$ by ?is circum/ance2 & boys1 :o are 9 ! habit ( ba?+1 %\ld be caution$ n to tru/ to ! app>5t %all[ness ( wat]1 z x w always prove deep] ?an x appe>s4 ,! refraction ( light prev5ts our see+ ! heav5ly bodies 9 _! real situation3 ! light !y s5d to u be+ refract$ 9 pass+ into ! atmosph]e1 we see ! sun & />s 9 ! direction ( ! refract$ ray2 z describ$ 9 fig4 #d1 plate #ai41 ! dott$ l9e repres5ts ! ext5t ( ! atmosph]e1 above a portion ( ! e>?1 ,e ,b ,e3 a ray ( light com+ f ! sun ,s1 falls obliquely on x1 at ,a1 & is refract$ to ,b2 !n1 s9ce we see ! object 9 ! direction ( ! refract$ ray1 a spectator at ,b1 w see an image ( ! sun at ,c1 in/ead ( its real situation1 at ,s4 ,emily4 ,b if ! sun 7 imm$iately ov] our heads1 its rays1 fall+ p]p5dicul>ly on ! atmosph]e1 w\ld n be refract$1 & we %\ld !n see ! real sun1 9 its true situation4 ,mrs4 ,b4 ,y mu/ recollect t ! sun1 is v]tical only to ! inhabitants ( ! torrid zone2 its rays1 !re=e1 are always refract$1 9 ?is latitude4 ,!re is also ano!r ob/acle to our see+ ! heav5ly bodies 9 _! real situations3 light1 ?\gh x moves ) extreme velocity1 is ab\t eight m9utes & a qu>t]1 9 its passage f ! sun to ! e>?2 !re=e1 :5 ! rays rea* u1 ! sun mu/ h quitt$ ! spot he occupi$ on _! dep>ture2 yet we see him 9 ! direction ( ^? rays1 & consequ5tly 9 a situation :i* he _h ab&on$ eight m9utes & a qu>t]1 be=e4 ,emily4 ,:5 y speak ( ! sun's motion1 y mean1 ,i suppose1 8 app>5t motion1 produc$ by ! diurnal motion ( ! e>?8 ,mrs4 ,b4 ,c]ta9ly2 ! effect be+ ! same1 :e!r x is our e>?1 or ! heav5ly bodies1 :i* move3 x is m easy to repres5t ?+s z !y appe> to be1 ?an z !y really are4 ,c>ol9e4 ,dur+ ! morn+1 !n1 :5 ! sun is ris+ t[>ds ! m]idian1 we mu/ 7f ! l5g? ( "t ! light is 9 rea*+ u7 see an image ( ! sun bel[ t spot :i* x really occupies4 ,emily4 ,b ! refraction ( ! atmosph]e1 c\nt]act+ ?is effect1 we may1 p]haps1 betwe5 ! two1 see ! sun 9 its real situation4 ,c>ol9e4 ,& 9 ! aft]noon1 :5 ! sun is s9k+ 9 ! we/1 refraction1 & ! l5g? ( "t :i* ! light is 9 rea*+ ! e>?1 w conspire to r5d] ! image ( ! sun1 high] ?an x really is4 ,mrs4 ,b4 ,! refraction ( ! sun's rays1 by ! atmosph]e1 prolongs our days1 z x occasions our see+ an image ( ! sun1 bo? be=e he rises1 & aft] he sets2 :5 bel[ our horizon1 he /ill %9es ^u ! atmosph]e1 & 8 rays are !nce refract$ to ! e>?3 s likewise we see an image ( ! sun1 previ\sly to 8 ris+1 ! rays t fall ^u ! atmosph]e be+ refract$ to ! e>?4 ,c>ol9e4 ,on ! o!r h&1 we mu/ recollect t light is eight m9utes & a qu>t] on its j\rney2 s t1 by ! "t x rea*es ! e>?1 ! sun may1 p]haps1 h ris5 above ! horizon4 ,emily4 ,pray1 d n glass w9d[s1 refract ! light8 ,mrs4 ,b4 ,!y d2 b ?is refraction w\ld n be p]ceptible1 7 ! surfaces ( ! glass1 p]fectly flat & p>allel1 because1 9 pass+ ?r\gh a pane ( glass1 ! rays suff] two refractions1 :i*1 be+ 9 contr>y directions1 produce ne>ly ! same effect z if no refraction _h tak5 place4 ,emily4 ,i d n und]/& t4 ,mrs4 ,b3 ,fig4 #e1 plate #ai1 w make x cle> to y3 ,a ,a repres5ts a ?ick pane ( glass1 se5 edgeways4 ,:5 ! ray ,b approa*es ! glass1 at ,c1 x is refract$ by x2 & in/ead ( cont9u+ its c\rse 9 ! same direction1 z ! dott$ l9e describes1 x passes ?r\gh ! pane1 to ,d2 at t po9t return+ into ! air1 x is aga9 refract$ by ! glass1 b 9 a contr>y direction to ! fir/ refraction1 & 9 consequ5ce proce$s to ,e4 ,n[ y mu/ obs]ve t ! ray ,b ,c & ! ray ,d ,e be+ p>allel1 ! light does n appe> to h suff]$ any refraction3 ! app>5t1 diff]+ s little f ! true place ( any object1 :5 se5 ?r\gh glass ( ord9>y ?ickness4 ,emily4 ,s t ! effect :i* takes place on ! ray ent]+ ! glass1 is undone on its quitt+ x4 ,or1 to express myself m sci5tifically1 :5 a ray ( light passes f "o m$ium into ano!r1 & ?r\gh t into ! fir/ aga91 ! two refractions be+ equal1 & 9 opposite directions1 no s5sible effect is produc$4 ,c>ol9e4 ,i ?9k ! effect is v s5sible1 =1 9 look+ ?r\gh ! glass ( ! w9d[1 ,i see objects v mu* di/ort$2 articles :i* ,i "k to be /raight1 appe> b5t & brok51 & sometimes ! p>ts seem to be sep>at$ to a di/ance f ea* o!r4 ,mrs4 ,b4 ,t is because common w9d[ glass is n flat1 its :ole surface be+ unev54 ,rays f any object1 fall+ ^u x "u diff]5t angles1 are1 consequ5tly1 refract$ 9 v>i\s ways1 & ?us produce ! di/ortion y h obs]v$4 ,emily4 ,is x n 9 consequ5ce ( refraction1 t ! glasses 9 common spectacles1 magnify objects se5 ?r\gh !m8 ,mrs4 ,b4 ,yes4 ,glasses ( ?is description are call$ l5ses2 ( ^!1 !re are sev]al k9ds1 ! names ( :i* x w be necess>y = y to le>n4 ,e l5s is =m$ ( glass1 gr\nd s z to =m a segm5t ( a sph]e1 on "o1 or bo? sides4 ,!y are all repres5t$ at fig4 #a1 plate #bj4 ,! mo/ common1 is ! d\ble convex l5s1 ,d4 ,?is is ?ick 9 ! middle1 & ?9 at ! edges1 l common spectacles1 or read+ glasses4 ,a ,b1 is a plano-convex l5s1 be+ flat on "o side1 & convex on ! o!r4 ,e is a d\ble concave1 be+1 9 all respects1 ! rev]se ( ,d4 ,c is a plano-concave1 flat on "o side1 & concave on ! o!r4 ,f is call$ a m5iscus1 or concavo-convex1 be+ concave on "o1 & convex on ! o!r side4 ,a l9e pass+ ?r\gh ! c5tre ( a l5s1 is call$ its axis4 ,c>ol9e4 ,i %\ld l to und]/& h[ ! rays ( light are refract$1 by means ( a l5s4 ,mrs4 ,b4 ,:5 p>allel rays 7fig4 #f7 fall on a d\ble convex l5s1 t only1 :i* falls 9 ! direction ( ! axis ( ! l5s1 is p]p5dicul> to ! surface2 ! o!r rays1 fall+ obliquely1 are refract$ t[>ds ! axis1 & w meet at a po9t beyond ! l5s1 call$ its focus4 ,( ! ?ree rays1 ,a ,b ,c1 :i* fall on ! l5s ,d ,e1 ! rays ,a & ,c are refract$ 9 _! passage ?r\gh x1 to a1 & c2 & on quitt+ ! l5s1 !y und]go a second refraction 9 ! same direction1 :i* unites !m ) ! ray ,b1 at ! focus ,f4 ,emily4 ,& :at is ! di/ance ( ! focus1 f ! surface ( ! l5s8 ,mrs4 ,b4 ,! focal di/ance dep5ds bo? ^u ! =m ( ! l5s1 & on ! refract+ p[] ( ! sub/ance ( :i* x is made3 9 a glass l5s1 bo? sides ( :i* are equally convex1 ! focus is situat$ ne>ly at ! c5tre ( ! sph]e1 ( :i* ! surface ( ! l5s =ms a portion2 x is at ! di/ance1 !re=e1 ( ! radius ( ! sph]e4 ,! prop]ty ( ^? l5ses :i* h a convex surface1 is to collect ! rays ( light to a focus2 & ( ^? :i* h a concave surface1 on ! contr>y1 to disp]se !m4 ,= ! rays ,a & ,c1 fall+ on ! concave l5s ,x ,y1 7fig4 #g1 plate #ai47 in/ead ( conv]g+ t[>ds ! ray ,b1 9 ! axis ( ! l5s1 w ea* be attract$ t[>ds ! ?ick edges ( ! l5s1 bo? on ent]+ & quitt+ x1 & w1 !re=e1 by ! fir/ refraction1 be made to div]ge to a1 c1 & by ! seconds1 to d1 e4 ,illu/ration3 ,,plate ,,xx4 ,c>ol9e4 ,& l5ses :i* h "o side flat1 & ! o!r convex1 or concave1 z ,a & ,b1 7fig4 #a1 plate #bj47 are1 ,i suppose1 less p[]ful 9 _! refractions8 ,mrs4 ,b4 ,yes2 ! focus ( ! plano-convex1 is at ! di/ance ( ! diamet] ( a sph]e1 ( :i* ! convex surface ( ! l5s1 =ms a portion2 z repres5t$ 9 figure #b1 plate #bj4 ,! ?ree p>allel rays1 ,a ,b ,c1 are br\ght to a focus by ! plano-convex l5s1 ,x ,y1 at ,f4 ,emily4 ,y h n expla9$ to u1 ,mrs4 ,b41 h[ ! l5s s]ves to magnify objects4 ,mrs4 ,b4 ,by turn+ aga9 to fig4 #f1 plate #ai4 y w readily und]/& ?is4 ,let ,a ,c1 be an object plac$ be=e ! l5s1 & suppose x to be se5 by an eye at ,f2 ! ray f ! po9t ,a1 w be se5 9 ! direction ,f ,g1 t f ,c1 9 ! direction ,f ,h2 ! visual angle1 !re=e1 w be greatly increas$1 & ! object mu/ appe> l>g]1 9 proportion4 ,i mu/ n[ expla9 to y ! refraction ( a ray ( light1 by a triangul> piece ( glass1 call$ a prism4 7,fig4 #c47 ,emily4 ,! ?ree sides ( ?is glass are flat2 x _c1 !re=e1 br+ ! rays to a focus2 nor d ,i suppose t its refraction w be simil> to t ( a flat pane ( glass1 because x has n two sides p>allel2 ,i _c1 !re=e1 conjecture :at effect ! refraction by a prism1 c produce4 ,mrs4 ,b4 ,! refractions ( ! ray1 bo? on ent]+ & on quitt+ ! prism1 are 9 ! same direction1 7,fig4 #c47 ,on ent]+ ! prism ,p1 ! ray ,a is refract$ f ,b to ,c1 & on quitt+ x f ,c to ,d4 ,9 ! fir/ in/ance x is refract$ t[>ds1 & 9 ! la/1 f ! p]p5dicul>2 ea* caus+ x to deviate 9 ! same way1 f its orig9al c\rse1 ,a ,b4 ,i w %[ y ?is by exp]im5t2 b = ?is purpose x w be advisable to close ! w9d[-%utt]s1 & admit1 ?r\gh ! small ap]ture1 a ray ( light1 :i* ,i %all refract1 by means ( ?is prism4 ,c>ol9e4 ,oh1 :at beautiful col\rs are repres5t$ on ! opposite wall6 ,!re are all ! col\rs ( ! ra9b[1 & ) a brightness1 ,i nev] saw equall$4 7,fig4 #d1 plate #bj47 ,emily4 ,i h se5 an effect1 9 "s respects simil> to ?is1 produc$ by ! rays ( ! sun %9+ ^u glass lu/res2 b h[ is x possible t a piece ( :ite glass c produce su* a v>iety ( brilliant col\rs8 ,mrs4 ,b4 ,! col\rs are n =m$ by ! prism1 b exi/$ 9 ! ray previ\sly to its refraction4 ,c>ol9e4 ,yet1 be=e its refraction1 x appe>$ p]fectly :ite4 ,mrs4 ,b4 ,! :ite rays ( ! sun1 are compos$ ( rays1 :i*1 :5 sep>at$1 produce all ^! col\rs1 al?\gh :5 bl5d$ toge!r1 !y appe> col\rless or :ite4 ,sir ,isaac ,newton1 to :om we are indebt$ = ! mo/ important discov]ies respect+ light & col\rs1 0 ! fir/ :o divid$ a :ite ray ( light1 & f\nd x to consi/ ( an assemblage ( col\r$ rays1 :i* =m$ an image ^u ! wall1 su* z y n[ see exhibit$1 7fig4 #d47 9 :i* are display$ ! foll[+ s]ies ( col\rs3 r$1 orange1 yell[1 gre51 blue1 indigo1 & violet4 ,emily4 ,b h[ does a prism sep>ate ^! col\r$ rays8 ,mrs4 ,b4 ,by refraction4 ,x appe>s t ! col\r$ rays h diff]5t degrees ( refrangibility2 9 pass+ ?r\gh ! prism1 !re=e1 !y take diff]5t directions accord+ to _! susceptibility ( refraction4 ,! violet rays deviate mo/ f _! orig9al c\rse2 !y appe> at "o ( ! ends ( ! spectrum1 ,a ,b3 contigu\s to ! violet1 are ! blue rays1 be+ ^? :i* h some:at less refrangibility2 !n foll[1 9 succession1 ! gre51 yell[1 orange1 & la/ly1 ! r$1 :i* are ! lea/ refrangible ( ! col\r$ rays4 ,c>ol9e4 ,i _c conceive h[ ^! col\rs1 mix$ toge!r1 c become :ite8 ,mrs4 ,b4 ,t ,i _c pret5d to expla93 b x is a fact t ! union ( ^! col\rs1 9 ! proportions 9 :i* !y appe> 9 ! spectrum1 produce 9 u ! idea ( :it5ess4 ,if y pa9t a circul> piece ( c>d1 9 comp>tm5ts1 ) ^! sev5 col\rs1 z ne>ly z possible 9 ! proportion1 & ( ! %ade exhibit$ 9 ! spectrum1 & :irl x rapidly on a p91 x w appe> :ite2 z ! velocity ( ! motion1 w h ! effect ( bl5d+ ! col\rs1 9 ! impression :i* !y make ^u ! eye4 ,b a m decisive pro( ( ! composition ( a :ite ray is af=d$1 by reunit+ ^! col\r$ rays1 & =m+ ) !m1 a ray ( :ite light4 ,c>ol9e4 ,if y c take a ray ( :ite light to pieces1 & put x toge!r aga91 ,i %all be q satisfi$4 ,mrs4 ,b4 ,?is c be done by lett+ ! col\r$ rays1 :i* h be5 sep>at$ by a prism1 fall ^u a l5s1 :i* w conv]ge !m to a focus2 & if1 :5 ?us reunit$1 we f9d t !y appe> :ite z !y did be=e refraction1 ,i hope y w be conv9c$ t ! :ite rays1 are a comp\nd ( ! sev]al col\r$ rays4 ,! prism ,p1 y see1 7fig4 #e47 sep>ates a ray ( :ite light1 into sev5 col\r$ rays1 & ! l5s ,l ,l br+s !m to a focus at ,f1 :]e !y aga9 appe> :ite4 ,c>ol9e4 ,y succe$ to p]fection3 ?is is inde$ a mo/ int]e/+ & conclusive exp]im5t4 ,emily4 ,yet1 ,mrs4 ,b41 ,i _c help ?9k+1 t !re may1 p]haps1 be b ?ree di/9ct col\rs 9 ! spectrum1 r$1 yell[1 & blue2 & t ! f\r o!rs may consi/ ( two ( ^! col\rs bl5d$ toge!r2 =1 9 pa9t+1 we f9d1 t by mix+ r$ & yell[1 we produce orange2 ) diff]5t proportions ( r$ & blue1 we make violet or any %ade ( purple2 & yell[1 & blue1 =m gre54 ,n[1 x is v natural to suppose1 t ! refraction ( a prism1 may n be s p]fect z to sep>ate ! col\r$ rays ( light completely1 & t ^? :i* are contigu\s1 9 ord] ( refrangibility1 may encroa* on ea* o!r1 & by mix+1 produce ! int]m$iate col\rs1 orange1 gre51 violet1 & indigo4 ,mrs4 ,b4 ,y\r obs]vation is1 ,i believe1 nei!r q wrong1 nor q "r4 ,dr4 ,wolla/on1 :o has p]=m$ _m exp]im5ts on ! refraction ( light1 9 a m accurate mann] ?an _h be5 previ\sly done1 by receiv+ a v n>r[ l9e ( light on a prism1 f\nd t x =m$ a spectrum1 consi/+ ( rays ( f\r col\rs only2 b !y 7 n exactly ^? y h nam$ z primitive col\rs1 = !y consi/$ ( r$1 gre51 blue1 & violet4 ,a v n>r[ l9e ( yell[ 0 visible1 at ! limit ( ! r$ & gre51 :i* ,dr4 ,wolla/on attribut$ to ! ov]lapp+ ( ! edges ( ! r$ & gre5 light4 ,c>ol9e4 ,b r$ & gre5 mix$ toge!r1 d n produce yell[8 ,mrs4 ,b4 ,n 9 pa9t+2 b x may be s 9 ! primitive rays ( ! spectrum4 ,dr4 ,wolla/on obs]v$1 t1 by increas+ ! bread? ( ! ap]ture1 by :i* ! l9e ( light 0 admitt$1 ! space occupi$ by ea* col\r$ ray 9 ! spectrum1 0 augm5t$1 9 proportion z ea* portion encroa*$ on ! neighb\r+ col\r1 & mix$ ) x2 s t ! int]v5tion ( orange & yell[1 betwe5 ! r$ & gre51 is ow+1 he supposes1 to ! mixture ( ^! two col\rs2 & ! blue is bl5d$ on ! "o side ) ! gre51 & on ! o!r ) ! violet1 =m+ ! spectrum1 z x 0 orig9ally obs]v$ by ,sir ,isaac ,newton1 & :i* ,i h j %[n y4 ,! ra9b[1 :i* exhibits a s]ies ( col\rs1 s analog\s to ^? ( ! spectrum1 is =m$ by ! refraction ( ! sun's rays1 9 _! passage ?r\gh a %[] ( ra92 e drop ( :i* acts z a prism1 9 sep>at+ ! col\r$ rays z !y pass ?r\gh x2 ! comb9$ effect ( innum]able drops1 produces ! b[1 :i* y "k c be se51 only :5 !re are bo? ra91 & sun%9e4 ,emily4 ,pray1 ,mrs4 ,b41 _c ! sun's rays be collect$ to a focus by a l5s1 9 ! same mann] z !y are by a concave mirror8 ,mrs4 ,b4 ,! same effect 9 conc5trat+ ! rays1 is produc$ by ! refraction ) a l5s1 z by ! reflection f a concave mirror3 9 ! fir/1 ! rays pass ?r\gh ! glass & conv]ge to a focus1 beh9d x1 9 ! latt]1 !y are reflect$ f ! mirror1 & br\ght to a focus1 be=e x4 ,a l5s1 :5 us$ = ! purpose ( collect+ ! sun's rays1 is call$ a burn+ glass4 ,i h be=e expla9$ to y1 ! mann] 9 :i* a convex l5s1 refracts ! rays1 & br+s !m to a focus2 7fig4 #f1 plate #ai47 z ^! rays conta9 bo? light & heat1 ! latt]1 z well z ! =m]1 is refract$2 & int5se heat1 z well z light1 w be f\nd 9 ! focal po9t4 ,! sun n[ %9es v bright2 if we let ! rays fall on ?is l5s1 y w p]ceive ! focus4 ,emily4 ,oh yes3 ! po9t ( union ( ! rays1 is v lum9\s4 ,i w hold a piece ( pap] 9 ! focus1 & see if x w take fire4 ,! spot ( light is extremely brilliant1 b ! pap] does n burn8 ,mrs4 ,b4 ,try a piece ( br[n pap]2--t1 y see1 takes fire almo/ imm$iately4 ,c>ol9e4 ,?is is surpris+2 = ! light appe>$ to %9e m int5sely1 on ! :ite1 ?an on ! br[n pap]4 ,mrs4 ,b4 ,! l5s collects an equal numb] ( rays to a focus1 :e!r y hold ! :ite or ! br[n pap]1 !re2 b ! :ite pap] appe>s m lum9\s 9 ! focus1 because mo/ ( ! rays1 in/ead ( ent]+ into ! pap]1 are reflect$ by x2 & ?is is ! reason t ! pap] does n readily take fire3 :il/1 on ! contr>y1 ! br[n pap]1 :i* absorbs m light & heat ?an x reflects1 soon becomes heat$ & takes fire4 ,c>ol9e4 ,?is is extremely curi\s2 b :y %\ld br[n pap]1 absorb m rays1 ?an :ite pap]8 ,mrs4 ,b4 ,i am f> f be+ able to give a satisfactory answ] to t "q4 ,we c =m b m]e conjecture on ?is po9t2 x is suppos$ t ! t5d5cy to absorb1 or reflect rays1 dep5ds on ! arrangem5t ( ! m9ute p>ticles ( ! body1 & t ?is div]sity ( arrangem5t r5d]s "s bodies susceptible ( reflect+ "o col\r$ ray1 & absorb+ ! o!rs2 :il/ o!r bodies1 h a t5d5cy to reflect all ! col\rs1 & o!rs aga91 to absorb !m all4 ,emily4 ,& h[ d y "k :i* col\rs bodies h a t5d5cy to reflect1 or :i* to absorb8 ,mrs4 ,b4 ,because a body always appe>s to be ( ! col\r :i* x reflects2 =1 z we see only by reflect$ rays1 x c appe> ( ! col\r ( ^? rays1 only4 ,c>ol9e4 ,b we see all bodies ( _! own natural col\r1 ,mrs4 ,b42 ! grass & trees1 gre52 ! sky1 blue2 ! fl[]s ( v>i\s hues4 ,mrs4 ,b4 ,true2 b :y is ! grass gre58--because x absorbs all1 except ! gre5 rays2 x is1 !re=e1 ^! only :i* ! grass & trees reflect to our eyes1 & ?is makes !m appe> gre54 ,! fl[]s1 9 ! same mann]1 reflect ! v>i\s col\rs ( :i* !y appe> to u2 ! rose1 ! r$ rays2 ! violet1 ! blue2 ! jonquil1 ! yell[1 c4 ,c>ol9e4 ,b ^! are ! p]man5t col\rs ( ! grass & fl[]s1 :e!r ! sun's rays %9e on !m or n4 ,mrs4 ,b4 ,:5ev] y see ^? col\rs1 ! fl[]s mu/ be illum9$ by "s light2 & light1 f :atev] s\rce x proce$s1 is ( ! same nature2 compos$ ( ! v>i\s col\r$ rays :i* pa9t ! grass1 ! fl[]s1 & e col\r$ object 9 nature4 ,c>ol9e4 ,b1 ,mrs4 ,b41 ! grass is gre51 & ! fl[]s are col\r$1 :e!r 9 ! d>k1 or expos$ to ! light8 ,mrs4 ,b4 ,:y %\ld y ?9k s8 ,c>ol9e4 ,x _c be o!rwise4 ,mrs4 ,b4 ,a mo/ philosophical reason inde$6 ,b1 z ,i nev] saw !m 9 ! d>k1 y w all[ me to diss5t f y\r op9ion4 ,c>ol9e4 ,:at col\r d y suppose !m to be1 !n1 9 ! d>k8 ,mrs4 ,b4 ,none at all2 or black1 :i* is ! same ?+4 ,y c nev] see objects1 )\t light4 ,:ite light is comp\nd$ ( rays1 f :i* all ! col\rs 9 nature are produc$2 !re1 !re=e1 c be no col\r )\t light2 & ?\gh a sub/ance is black1 or )\t col\r1 9 ! d>k1 x may become col\r$1 z soon z x becomes visible4 ,x is visible1 inde$1 only by ! col\r$ rays :i* x reflects2 !re=e1 we c see x only :5 col\r$4 ,c>ol9e4 ,all y say seems v true1 & ,i "k n :at to object to x2 yet x appe>s at ! same "t incr$ible6 ,:at1 ,mrs4 ,b41 are we all z black z negroes 9 ! d>k8 y make me %udd] at ! ?\ght4 ,mrs4 ,b4 ,y\r vanity ne$ n be al>m$ at ! idea1 z y are c]ta9 ( nev] be+ se51 9 t /ate4 ,c>ol9e4 ,t is "s consolation1 und\bt$ly2 b :at a melan*oly reflection x is1 t all nature :i* appe>s s beautifully div]sifi$ ) col\rs1 is really "o uni=m mass ( blackness6 ,mrs4 ,b4 ,is nature less pleas+ = be+ col\r$1 z well z illum9$1 by ! rays ( light8 & are col\rs less beautiful1 = be+ accid5tal1 r ?an ess5tial prop]ties ( bodies8 ,provid5ce seems to h decorat$ nature ) ! en*ant+ div]sity ( col\rs1 :i* we s mu* admire1 = ! sole purpose ( beautify+ ! sc5e1 & r5d]+ x a s\rce ( s5sible gratification3 x is an ornam5t :i* embelli%es nature1 :5ev] we behold h]4 ,:at reason is !re to regret1 t %e does n we> x :5 %e is invisible8 ,emily4 ,i confess1 ,mrs4 ,b41 t ,i h _h my d\bts1 z well z ,c>ol9e1 ?\gh %e has sp>$ me ! pa9s ( express+ !m3 b ,i h j ?\ght ( an exp]im5t1 :i*1 if x succe$1 w1 ,i am sure1 satisfy u bo?4 ,x is c]ta91 t we _c see bodies 9 ! d>k1 to "k :e!r !y h !n any col\r4 ,b we may place a col\r$ body 9 a ray ( light1 :i* has be5 refract$ by a prism2 & if y\r !ory is true1 ! body1 ( :atev] col\r x naturally is1 mu/ appe> ( ! col\r ( ! ray 9 :i* x is plac$2 = s9ce x receives no o!r col\r$ rays1 x c reflect no o!rs4 ,c>ol9e4 ,oh6 t is an excell5t ?\ght1 ,emily2 w y /& ! te/1 ,mrs4 ,b48 ,mrs4 ,b4 ,i cons5t3 b we mu/ d>k5 ! room1 & admit only ! ray :i* is to be refract$2 o!rwise1 ! :ite rays w be reflect$ on ! body "u trial1 f v>i\s p>ts ( ! room4 ,) :at d y *oose to make ! exp]im5t8 ,c>ol9e4 ,?is rose3 look at x1 ,mrs4 ,b41 & tell me :e!r x is possible to deprive x ( its beautiful col\r8 ,mrs4 ,b4 ,we %all see4--,i expose x fir/ to ! r$ rays1 & ! fl[] appe>s ( a m brilliant hue2 b obs]ve ! gre5 leaves---- ,c>ol9e4 ,!y appe> nei!r r$ nor gre52 b ( a d+y br[n ) a r$di% gl[8 ,mrs4 ,b4 ,!y _c appe> gre51 because !y h no gre5 rays to reflect2 nei!r are !y r$1 because gre5 bodies absorb mo/ ( ! r$ rays4 ,b ?\gh bodies1 f ! arrangem5t ( _! p>ticles1 h a t5d5cy to absorb "s rays1 & reflect o!rs1 yet x is n natural to suppose1 t bodies are s p]fectly uni=m 9 _! arrangem5t1 z to reflect only pure rays ( "o col\r1 & p]fectly to absorb ! o!rs2 x is f\nd1 on ! contr>y1 t a body reflects1 9 great abundance1 ! rays :i* det]m9e its col\r1 & ! o!rs 9 a great] or less degree1 9 proportion z !y are ne>] to or fur!r f its own col\r1 9 ! ord] ( refrangibility4 ,! gre5 leaves ( ! rose1 !re=e1 w reflect a few ( ! r$ rays1 :i*1 bl5d$ ) _! natural blackness1 give !m t br[n t+e3 if !y reflect$ none ( ! r$ rays1 !y w\ld appe> p]fectly black4 ,n[ ,i %all hold ! rose 9 ! blue rays---- ,c>ol9e4 ,oh1 ,emily1 ,mrs4 ,b4 is "r6 look at ! rose3 x is no long] r$1 b ( a d+y blue col\r4 ,emily4 ,?is is ! mo/ wond]ful1 ( any ?+ we h yet le>nt4 ,b1 ,mrs4 ,b41 :at is ! reason t ! gre5 leaves1 are ( a bright] blue ?an ! rose8 ,mrs4 ,b4 ,! gre5 leaves reflect bo? blue & yell[ rays1 :i* produce a gre5 col\r4 ,!y are n[ 9 a col\r$ ray1 :i* !y h a t5d5cy to reflect2 !y1 !re=e1 reflect m ( ! blue rays ?an ! rose1 7:i* naturally absorbs t col\r17 & w1 ( c\rse1 appe> ( a bright] blue4 ,emily4 ,yet1 9 pass+ ! rose ?r\gh ! diff]5t col\rs ( ! spectrum1 ! fl[] takes !m m readily ?an ! leaves4 ,mrs4 ,b4 ,because ! fl[] is ( a pal] hue4 ,bodies :i* reflect all ! rays1 are :ite2 ^? :i* absorb !m all1 are black3 betwe5 ^! extremes1 bodies appe> light] or d>k]1 9 proportion to ! quantity ( rays !y reflect or absorb4 ,?is rose is ( a pale r$2 x approa*es ne>] to :ite ?an to black1 & !re=e1 reflects rays1 m abundantly ?an x absorbs !m4 ,emily4 ,b if a rose has s /rong a t5d5cy to reflect rays1 ,i %\ld imag9e t x w\ld be ( a deep r$ col\r4 ,mrs4 ,b4 ,i mean to say1 t x has a g5]al t5d5cy to reflect rays4 ,pale col\r$ bodies1 reflect all ! col\r$ rays to a c]ta9 degree1 _! pal5ess1 be+ an approa* t[>ds :it5ess3 b !y reflect "o col\r m ?an ! re/3 ?is pr$om9ates ov] ! :ite1 & det]m9es ! col\r ( ! body4 ,s9ce1 !n1 bodies ( a pale col\r1 9 "s degree reflect all ! rays ( light1 9 pass+ ?r\gh ! v>i\s col\rs ( ! spectrum1 !y w reflect !m all1 ) tol]able brilliancy2 b w appe> mo/ vivid1 9 ! ray ( _! natural col\r4 ,! gre5 leaves1 on ! contr>y1 are ( a d>k col\r1 be>+ a /rong] resemblance to black1 ?an to :ite2 !y h1 !re=e1 a great] t5d5cy to absorb1 ?an to reflect rays2 & reflect+ v few ( any1 b ! blue1 & yell[ rays1 !y w appe> d+y1 9 pass+ ?r\gh ! o!r col\rs ( ! spectrum4 ,c>ol9e4 ,!y mu/1 h[ev]1 reflect great quantities ( ! gre5 rays1 to produce s deep a col\r4 ,mrs4 ,b4 ,deepness or d>kness ( col\r1 proce$s r f a defici5cy1 ?an an abundance ( reflect$ rays4 ,rememb]1 t if bodies reflect$ none ( ! rays1 !y w\ld be black2 & if a body reflects only a few gre5 rays1 x w appe> ( a d>k gre52 x is ! brightness1 & int5sity ( ! col\r1 :i* %[ t a great quantity ( rays are reflect$4 ,emily4 ,a :ite body1 !n1 :i* reflects all ! rays1 w appe> equally bright 9 all ! col\rs ( ! spectrum4 ,mrs4 ,b4 ,c]ta9ly4 ,& ?is is easily prov$ by pass+ a %eet ( :ite pap]1 ?r\gh ! rays ( ! spectrum4 ,:ite1 y p]ceive1 results f a body reflect+ all ! rays :i* fall ^u x2 black1 is produc$1 :5 !y are all absorb$2 & col\r1 arises f a body possess+ ! p[] to decompose ! sol> ray1 by absorb+ "s p>ts1 & reflect+ o!rs4 ,c>ol9e4 ,:at is ! reason t articles :i* are blue1 (t5 appe> gre51 by c&le-light8 ,mrs4 ,b4 ,! light ( a c&le1 is n ( s pure a :ite z t ( ! sun3 x has a yell[i% t+e1 & :5 refract$ by ! prism1 ! yell[ rays pr$om9ate2 & blue bodies reflect "s ( ! yell[ rays1 f _! be+ next to ! blue1 9 ! ord] ( refrangibility2 ! sup]abundance ( yell[ rays1 :i* is suppli$ by ! c&le1 gives to blue bodies1 a gre5i% hue4 ,c>ol9e4 ,c&le-light mu/ !n give to all bodies1 a yell[i% t+e1 f ! excess ( yell[ rays2 & yet x is a common rem>k1 t p ( a sall[ complexion1 appe> fair]1 or :it]1 by c&le-light4 ,mrs4 ,b4 ,! yell[ ca/ ( _! complexion is n s /rik+1 :5 e surr\nd+ object has a yell[ t+e4 ,emily4 ,pray1 :y does ! sun appe> r$1 ?r\gh a fog8 ,illu/ration3 ,,plate ,,xxi4 ,mrs4 ,b4 ,x is suppos$ to be ow+ to ! rays1 :i* are mo/ refrangible1 be+ also ! mo/ easily reflect$3 9 pass+ ?r\gh an atmosph]e1 load$ ) moi/ure1 z 9 foggy wea!r1 & also 9 ! morn+ & ev5+1 :5 mi/s prevail1 ! violet1 indigo1 blue1 & gre5 rays1 are reflect$ back by ! p>ticles :i* load ! air2 :il/ ! yell[1 orange1 & r$ rays1 be+ less susceptible ( reflection1 pass on1 & rea* ! eye4 ,c>ol9e4 ,&1 pray1 :y is ! sky ( a blue col\r8 ,mrs4 ,b4 ,y %\ld r say1 ! atmosph]e2 = ! sky is a v vague t]m1 ! mean+ ( :i*1 x w\ld be difficult to def9e1 philosophically4 ,c>ol9e4 ,b ! col\r ( ! atmosph]e %\ld be :ite1 s9ce all ! rays trav]se x1 9 _! passage to ! e>?4 ,mrs4 ,b4 ,d n =get t ! direct rays ( light :i* pass f ! sun to ! e>?1 d n meet our eyes1 except+ :5 we are look+ at t lum9>y1 & ?us int]cept !m2 9 :i* case1 y "k1 t ! sun appe>s :ite4 ,! atmosph]e is a transp>5t m$ium1 ?r\gh :i* ! sun's rays pass freely to ! e>?2 b ! p>ticles ( :i* x is compos$1 also reflect ! rays ( light1 & x appe>s t !y possess ! prop]ty ( reflect+ ! blue rays1 ! mo/ copi\sly3 ! light1 !re=e1 :i* is reflect$ back into ! atmosph]e1 f ! surface ( ! e>?1 falls ^u ^! p>ticles ( air1 & ! blue rays are return$ by reflection3 ?is reflection is p]=m$ 9 e possible direction2 s t :5ev] we look at ! atmosph]e1 "s ( ^! rays fall ^u our eyes2 h5ce we see ! air ( a blue col\r4 ,if ! atmosph]e did n reflect any rays1 ?\gh ! objects1 on ! surface ( ! e>?1 w\ld be illum9at$1 ! sky w\ld appe> p]fectly black4 ,c>ol9e4 ,oh1 h[ melan*oly w\ld t be2 & h[ p]nici\s to ! sight1 to be con/antly view+ bright objects aga9/ a black sky4 ,b :at is ! reason t bodies (t5 *ange _! col\r2 z leaves1 :i* )] 9 autumn1 or a spot ( ink1 :i* produces an iron-m\ld on l958 ,mrs4 ,b4 ,x arises f "s *emical *ange1 :i* takes place 9 ! arrangem5t ( ! compon5t p>ts2 by :i* !y lose _! t5d5cy to reflect c]ta9 col\rs1 & acquire ! p[] ( reflect+ o!rs4 ,a )]$ leaf ?us no l+] reflects ! blue rays2 x appe>s1 !re=e1 yell[1 or has a slight t5d5cy to reflect sev]al rays1 :i* produce a d+y br[n col\r4 ,an ink spot on l951 at fir/ absorbs all ! rays2 b1 f ! action ( soap1 or ( "s o!r ag5t1 x und]goes a *emical *ange1 & ! spot p>tially rega9s its t5d5cy to reflect col\rs1 b ) a pref]5ce to reflect ! yell[ rays1 & su* is ! col\r ( ! iron-m\ld4 ,emily4 ,bodies1 !n1 f> f be+ ( ! col\r :i* !y appe> to possess1 are ( t col\r to :i* !y h ! greate/ av]sion1 ) :i* !y w n incorporate1 b reject1 & drive f !m4 ,mrs4 ,b4 ,x c]ta9ly is s2 ?\gh ,i sc>cely d>e v5ture to advance su* an op9ion1 :il/ ,c>ol9e is contemplat+ h] beautiful rose4 ,c>ol9e4 ,my poor rose6 y are n satisfi$ ) depriv+ x ( col\r1 b ev5 make x h an av]sion to x2 & ,i am unable to contradict y4 ,emily4 ,s9ce d>k bodies1 absorb m sol> rays ?an light ones1 ! =m] %\ld soon] be heat$ if expos$ to ! sun8 ,mrs4 ,b4 ,& !y are f\nd1 by exp]i5ce1 to be s4 ,h y nev] obs]v$ a black dress1 to be w>m] ?an a :ite "o8 ,emily4 ,yes1 & a :ite "o m dazzl+3 ! black is heat$ by absorb+ ! rays1 ! :ite is dazzl+1 by reflect+ !m4 ,c>ol9e4 ,& ?is 0 ! reason t ! br[n pap] 0 burnt 9 ! focus ( ! l5s1 :il/ ! :ite pap] exhibit$ ! mo/ lum9\s spot1 b did n take fire4 ,mrs4 ,b4 ,x 0 s4 ,x is n[ full "t to conclude our lesson4 ,at our next meet+1 ,i %all give y a description ( ! eye4 ,que/ions #a4 7,pg4 #agi7 ,:at is meant by ! refraction ( light8 #b4 7,pg4 #agi7 ,:at is believ$ to be ! cause ( refraction8 #c4 7,pg4 #ahj7 ,h[ is a ray refract$ 9 pass+ obliquely f air into wat]8 #d4 7,pg4 #ahj7 ,h[ is ?is refraction expla9$ 9 fig4 #a1 plate #ai8 #e4 7,pg4 #ahj7 ,:at is fig4 #b int5d$ to expla98 #f4 7,pg4 #ahj7 ,:at is ! rule respect+ refraction1 by diff]5t m$iums8 #g4 7,pg4 #aha7 ,:at is meant by ! p]p5dicul>8 #h4 7,pg4 #aha7 ,h[ does fig4 #c1 plate #ai1 elucidate ! law ( refraction8 #i4 7,pg4 #aha7 ,:at w be ! effect on ! app>5t situation ( ! fl[]8 #aj4 7,pg4 #aha7 ,:at effect has refraction ^u ! app>5t dep? ( a /ream ( wat]8 #aa4 7,pg4 #ahb7 ,h[ does ! atmosph]e refract ! rays ( ! sun1 z repres5t$1 fig4 #d8 #ab4 7,pg4 #ahb7 ,:y h we ! rays ( ! sun always refract$8 #ac4 7,pg4 #ahb7 ,:at l5g? ( "t is requir$ = light to travel f ! sun1 to ! e>?8 #ad4 7,pg4 #ahb7 ,:at effect has ?is ^u 8 app>5t place8 #ae4 7,pg4 #ahb7 ,h[ is ! l5g? ( ! day affect$ by refraction8 #af4 7,pg4 #ahc7 ,h[ are rays refract$1 :i* fall obliquely ^u a flat pane ( glass1 7fig4 #e1 plate #ai87 #ag4 7,pg4 #ahc7 ,:at is ! reason t objects are di/ort$1 :5 se5 ?r\gh common w9d[ glass8 #ah4 7,pg4 #ahd7 ,:at is meant by a l5s8 #ai4 7,pg4 #ahd7 ,:at are ! five k9ds call$1 repres5t$ at fig4 #a1 plate #bj8 #bj4 7,pg4 #ahd7 ,:at is meant by ! axis ( a l5s8 #ba4 7,pg4 #ahd7 ,h[ are p>allel rays1 refract$ by ! d\ble convex l5s1 fig4 #f1 plate #ai8 #bb4 7,pg4 #ahd7 ,:at is meant by ! focus ( a l5s8 #bc4 7,pg4 #ahd7 ,:at is ! focal di/ance ( p>allel rays1 f a d\ble convex l5s8 #bd4 7,pg4 #ahd7 ,h[ are ! rays refract$ by a concave l5s1 fig4 #g1 plate #ai8 #be4 7,pg4 #ahe7 ,:at is ! effect ( "o plane side 9 a l5s8 #bf4 7,pg4 #ahe7 ,h[ is ! focus ( ! plano-convex l5s situat$1 fig4 #b1 plate #bj8 #bg4 7,pg4 #ahe7 ,h[ does a convex l5s magnify objects1 fig4 #f1 plate #ai8 #bh4 7,pg4 #ahe7 ,:at is ! article d5om9at$ :i* is repres5t$ at fig4 #c1 plate #bj8 #bi4 7,pg4 #ahe7 ,h[ w a ray be refract$1 :i* ent]s on "o side ( ! prism1 9 ! direction ,a ,b8 #cj4 7,pg4 #ahe7 ,:at effect is produc$ by ?is refraction1 z repres5t$ 9 fig4 #d1 plate #bj8 #ca4 7,pg4 #ahf7 ,( :at are ! rays ( :ite light said to be compos$8 #cb4 7,pg4 #ahf7 ,:at col\rs are produc$8 #cc4 7,pg4 #ahf7 ,by :at prop]ty1 9 light1 does refraction enable u to sep>ate ^! diff]5t rays8 #cd4 7,pg4 #ahg7 ,:at exp]im5t may be p]=m$ ) a piece ( c>d1 s z to exemplify ! comp\nd nature ( light8 #ce4 7,pg4 #ahg7 ,h[ c ! same be %[n by a l5s1 fig4 #e4 plate #bj8 #cf4 7,pg4 #ahg7 ,is x c]ta9 t !re are sev5 primitive col\rs 9 ! spectrum8 #cg4 7,pg4 #ahh7 ,h[ is ! ra9b[ produc$1 & :at is necess>y to its production8 #ch4 7,pg4 #ahh7 ,h[ are ! sol> rays affect$ by a convex l5s8 #ci4 7,pg4 #ahh7 ,:y is su* a l5s1 call$ a burn+ glass8 #dj4 7,pg4 #ahh7 ,:y are bodies ( a d>k col\r1 m readily inflam$1 ?an ^? :i* are :ite8 #da4 7,pg4 #ahi7 ,:at is believ$ to be ! reason1 :y "s bodies absorb m rays ?an o!rs8 #db4 7,pg4 #ahi7 ,:at det]m9es ! col\r ( any p>ticul> body8 #dc4 7,pg4 #ahi7 ,:at exemplifications are giv58 #dd4 7,pg4 #ahi7 ,by :at reason+ is x prov$1 t bodies d n reta9 _! col\rs 9 ! d>k8 #de4 7,pg4 #aij7 ,:at pro( ( ! tru? ( ?is !ory ( col\rs1 may be af=d$ by ! prism8 #df4 7,pg4 #aia7 ,:y w gre5 leaves1 :5 expos$ to ! r$ ray1 appe> ( a d+y br[n8 #dg4 7,pg4 #aia7 ,bodies1 9 g5]al1 :5 plac$ 9 a ray diff]+ 9 col\r f _! own1 appe> ( a mix$ hue1 :at causes ?is8 #dh4 7,pg4 #aia7 ,:y w bodies ( a pale1 or light hue1 mo/ p]fectly1 assume ! diff]5t col\rs ( ! spectrum8 #di4 7,pg4 #aib7 ,^u :at prop]ty 9 a body1 does ! d>kness ( its col\r dep5d8 #ej4 7,pg4 #aib7 ,:y d "s bodies appe> :ite1 o!rs black1 & o!rs ( diff]5t col\rs8 #ea4 7,pg4 #aib7 ,f :at cause d blue articles appe> gre51 by c&le-light8 #eb4 7,pg4 #aic7 ,:at is believ$ to be ! cause1 ( ! r$ appe>ance ( ! sun1 ?r\gh a fog1 or mi/y atmosph]e8 #ec4 7,pg4 #aic7 ,f :at is ! blue col\r ( ! sky1 ?\ght to arise8 #ed4 7,pg4 #aic7 ,:at w\ld be ! col\r ( ! sky1 did n ! atmosph]e reflect light8 #ee4 7,pg4 #aic7 ,f :at cause d "s bodies *ange _! col\r1 z leaves =m]ly gre51 become br[n1 & ink1 yell[8 #ef4 7,pg4 #aid7 ,:y is a black dress1 w>m] 9 ! sun%9e1 ?an a :ite "o ( ! same texture8 ,,conv]sation ,,xvii4 ,,on ,,! ,,/ructure ,,( ,,! ,,eye1 ,,& ,,optical ,,in/rum5ts4 ,,description ,,( ,,! ,,eye4 ,,( ,,! ,,image ,,on ,,! ,,ret9a4 ,,refraction ,,by ,,! ,,hum\rs ,,( ,,! ,,eye4 ,,( ,,! ,,use ,,( ,,spectacles4 ,,( ,,! ,,s+le ,,microscope4 ,,( ,,! ,,d\ble ,,microscope4 ,,( ,,! ,,sol> ,,microscope4 ,,magic ,,lan?orn4 ,,refract+ ,,telescope4 ,,reflect+ ,,telescope4 ,,mrs4 ,b4 ,! body ( ! eye1 is ( a sph]ical =m3 7fig4 #a4 plate #ba47 x has two membran\s coats1 or cov]+s2 ! ext]nal "o1 a a a1 is call$ ! scl]otica1 ?is is commonly kn[n "u ! "n ( ! :ite ( ! eye2 x has a projection 9 t "p ( ! eye :i* is expos$ to view1 b b1 :i* is call$ ! transp>5t cornea1 because1 :5 dri$1 x has ne>ly ! consi/5ce ( v f9e horn1 & is suffici5tly transp>5t = ! light to obta9 free passage ?r\gh x4 ,! second membrane :i* l9es ! cornea1 & envelops ! eye1 is call$ ! *oroid1 c c c2 ?is has an op5+ 9 front1 j b5ea? ! cornea1 :i* =ms ! pupil1 or sight ( ! eye1 d d1 ?r\gh :i* ! rays ( light pass into ! eye4 ,! pupil is surr\nd$ by a col\r$ bord] call$ ! iris1 e e1 :i*1 by its muscul> motion1 always pres]ves ! pupil ( a circul> =m1 :e!r x is exp&$ 9 ! d>k1 or contract$ by a /rong light4 ,?is y w und]/& bett] by exam9+ fig4 #b4 ,emily4 ,i did n "k t ! pupil 0 susceptible ( v>y+ its dim5sions4 ,mrs4 ,b4 ,! con/ruction ( ! eye is s admirable1 t x is capable ( adapt+ itself1 m or less1 to ! circum/ances 9 :i* x is plac$4 ,9 a fa9t light1 ! pupil dilates s z to receive an additional quantity ( rays1 & 9 a /rong light1 x contracts1 9 ord] to prev5t ! int5sity ( ! light f injur+ ! optic n]ve4 ,obs]ve ,emily's eyes1 z %e sits look+ t[>ds ! w9d[s3 ! pupils appe> v small1 & ! iris1 l>ge4 ,n[1 ,emily1 turn f ! light1 & cov] y\r eyes ) y\r h&1 s z entirely to exclude x1 = a few mom5ts4 ,c>ol9e4 ,h[ v mu* ! pupils ( h] eyes are n[ enl>g$1 & ! iris dim9i%$6 ,?is is1 no d\bt1 ! reason :y ! eyes suff] pa91 :5 f d>kness1 !y sudd5ly come into a /rong light2 = ! pupil be+ dilat$1 a quantity ( rays mu/ ru% 91 be=e x has "t to contract4 ,emily4 ,& :5 we g f a /rong light1 into obscurity1 we at fir/ imag9e ourselves 9 total d>kness2 = a suffici5t numb] ( rays _c ga9 admittance into ! contract$ pupil1 to enable u to di/+ui% objects3 b 9 a few m9utes x dilates1 & we cle>ly p]ceive objects :i* 7 be=e invisible4 ,mrs4 ,b4 ,x is j s4 ,! *oroid c c1 is embu$ ) a black liquor1 :i* s]ves to absorb all ! rays t are irregul>ly reflect$1 & to conv]t ! body ( ! eye1 into a m p]fect cam]a obscura4 ,:5 ! pupil is exp&$ to its utmo/ ext5t1 x is capable ( admitt+ t5 times ! quantity ( light1 t x does :5 mo/ contract$4 ,9 cats1 & animals :i* are said to see 9 ! d>k1 ! p[] ( dilatation & contraction ( ! pupil1 is /ill great]2 x is comput$ t ! pupils ( _! eyes may admit "o hundr$ times m light at "o "t ?an at ano!r4 ,)9 ^! cov]+s ( ! eye-ball1 are conta9$1 ?ree transp>5t sub/ances1 call$ hum\rs4 ,! fir/ occupies ! space imm$iately beh9d ! cornea1 & is call$ ! aque\s hum\r1 f f1 f its liquidity & its resemblance to wat]4 ,beyond ?is1 is situat$ ! cry/all9e hum\r1 g g1 s call$ f its cle>ness & transp>5cy3 x has ! =m ( a l5s1 & refracts ! rays ( light 9 a great] degree ( p]fection1 ?an any t h be5 con/ruct$ by art3 x is atta*$ by two muscles1 m m1 to ea* side ( ! *oroid4 ,! back "p ( ! eye1 betwe5 ! cry/all9e hum\r & ! ret9a1 is fill$ by ! vitre\s hum\r1 h h1 :i* d]ives its "n f a resemblance x is suppos$ to be>1 to glass1 or vitrifi$ sub/ances4 ,illu/ration3 ,,plate ,,xxii4 ,! membran\s cov]+s ( ! eye are int5d$ *iefly = ! pres]vation ( ! ret9a1 i i1 :i* is by f> ! mo/ important "p ( ! eye1 z x is t :i* receives ! impression ( ! objects ( sight1 & conveys x to ! m9d4 ,! ret9a is =m$ by ! expansion ( ! optic n]ve1 & is ( a mo/ p]fect :it5ess3 ?is n]ve proce$s f ! bra91 ent]s ! eye1 at n1 on ! side next ! nose1 & is f9ely spread ov] ! int]ior surface ( ! *oroid4 ,! rays ( light :i* ent] ! eye1 by ! pupil1 are refract$ by ! sev]al hum\rs 9 _! passage ?r\gh !m1 & unite 9 a focus on ! ret9a4 ,c>ol9e4 ,i d n und]/& ! use ( ^! refract+ hum\rs3 ! image ( objects 0 repres5t$ 9 ! cam]a obscura1 )\t any su* assi/ance4 ,mrs4 ,b4 ,t is true2 b ! repres5tation became mu* m /rong & di/9ct1 :5 we enl>g$ ! op5+ ( ! cam]a obscura1 & receiv$ ! rays into x1 ?r\gh a l5s4 ,i h told y1 t rays proce$ f bodies 9 all possible directions4 ,we mu/1 !re=e1 consid] e "p ( an object :i* s5ds rays to our eyes1 z po9ts f :i* ! rays div]ge1 z f a c5tre4 ,emily4 ,^! div]g5t rays1 issu+ f a s+le po9t1 ,i believe y told u1 7 call$ a p5cil ( rays8 ,mrs4 ,b4 ,yes4 ,n[1 div]g5t rays1 on ent]+ ! pupil1 d n cross ea* o!r2 ! pupil1 h[ev]1 is suffici5tly l>ge to admit a small p5cil ( !m2 & ^!1 if n refract$ to a focus1 by ! hum\rs1 w\ld cont9ue div]g+ aft] !y _h pass$ ! pupil1 w\ld fall disp]s$ ^u ! ret9a1 & ?us ! image ( a s+le po9t1 w\ld be exp&$ ov] a l>ge portion ( ! ret9a4 ,! div]g5t rays f e o!r po9t ( ! object1 w\ld be spread ov] a simil> ext5t ( space1 & w\ld int]f]e & be conf\nd$ ) ! fir/2 s t no di/9ct image c\ld be =m$1 & ! repres5tation on ! ret9a w\ld be confus$1 bo? 9 figure & col\r4 ,fig4 #c4 repres5ts two p5cils ( rays1 issu+ f two po9ts ( ! tree1 ,a ,b1 & ent]+ ! pupil ,c1 refract$ by ! cry/all9e hum\r ,d1 & =m+ on ! ret9a1 at a b1 di/9ct images ( ! spot !y proce$ f4 ,fig4 #d4 diff]s f ! prec$+1 m]ely f n be+ suppli$ ) a l5s2 9 consequ5ce ( :i*1 ! p5cils ( rays are n refract$ to a focus1 & no di/9ct image is =m$ on ! ret9a4 ,i h del9eat$ only ! rays issu+ f two po9ts ( an object1 & di/+ui%$ ! two p5cils 9 fig4 #d4 by describ+ "o ( !m ) dott$ l9es3 ! int]f]5ce ( ^! two p5cils ( rays on ! ret9a1 w enable y to =m an idea ( ! confusion :i* w\ld arise1 f ?\s&s & millions ( po9ts1 at ! same in/ant p\r+ _! div]g5t rays ^u ! ret9a4 ,emily4 ,true2 b ,i d n yet well und]/&1 h[ ! refract+ hum\rs1 rem$y ?is imp]fection4 ,mrs4 ,b4 ,! refraction ( ^! sev]al hum\rs1 unites ! :ole ( a p5cil ( rays1 proce$+ f any "o po9t ( an object1 to a correspond+ po9t on ! ret9a1 & ! image is ?us r5d]$ di/9ct & /rong4 ,if y conceive1 9 fig4 #c41 e po9t ( ! tree to s5d =? a p5cil ( rays1 simil> to ^? f ,a ,b1 e "p ( ! tree w be z accurately repres5t$ on ! ret9a1 z ! po9ts a b4 ,emily4 ,h[ admirably1 h[ wond]fully1 is ?is contriv$6 ,c>ol9e4 ,b s9ce ! eye absolutely requires refract+ hum\rs1 9 ord] to h a di/9ct repres5tation =m$ on ! ret9a1 :y is n ! same refraction equally necess>y1 = ! images =m$ 9 ! cam]a obscura8 ,mrs4 ,b4 ,x is2 except+ ! ap]ture ?r\gh :i* we receive ! rays into ! cam]a obscura1 is extremely small2 s t b v few ( ! rays div]g+ f a po9t1 ga9 admittance2 b :5 we enl>g$ ! ap]ture1 & furni%$ x ) a l5s1 y f\nd ! l&scape m p]fectly repres5t$4 ,c>ol9e4 ,i rememb] h[ obscure & confus$ ! image 01 :5 y enl>g$ ! op5+1 )\t putt+ 9 ! l5s4 ,mrs4 ,b4 ,su*1 or v simil>1 w\ld be ! repres5tation on ! ret9a1 unassi/$ by ! refract+ hum\rs4 ,y w n[ be able to und]/& ! nature ( t imp]fection ( sight1 :i* arises f ! eyes be+ too prom95t4 ,9 su* cases1 ! cry/all9e hum\r1 ,d1 7fig4 #e47 be+ extremely convex1 refracts ! rays too mu*1 & collects a p5cil1 proce$+ f ! object ,a ,b1 into a focus1 ,f1 be=e !y rea* ! ret9a4 ,f ?is focus1 ! rays proce$1 div]g+1 & consequ5tly =m a v confus$ image on ! ret9a1 at a b4 ,?is is ! defect 9 %ort-sight$ p4 ,emily4 ,i und]/& x p]fectly4 ,b :y is ?is defect rem$i$ by br++ ! object ne>] to ! eye1 z we f9d to be ! case ) %ort-sight$ p8 ,mrs4 ,b4 ,! ne>] y br+ an object to y\r eye1 ! m div]g5t ! rays fall ^u ! cry/all9e hum\r1 & consequ5tly !y are n s soon conv]g$ to a focus3 ?is focus1 !re=e1 ei!r falls ^u ! ret9a1 or at lea/ approa*es ne>] to x1 & ! object is proportionally di/9ct1 z 9 fig4 #f4 ,emily4 ,! ne>]1 !n1 y br+ an object to a l5s1 ! fur!r ! image rec$es beh9d x4 ,mrs4 ,b4 ,c]ta9ly4 ,b %ort-sight$ p]sons h ano!r res\rce1 = objects :i* !y c n br+ ne> to _! eyes2 ?is is1 to place a concave l5s1 ,c ,d1 7fig4 #a1 plate #bb47 be=e ! eye1 9 ord] to increase ! div]g5ce ( ! rays4 ,! effect ( a concave l5s1 is1 y "k1 exactly ! rev]se ( a convex "o3 x r5d]s p>allel rays div]g5t1 & ^? :i* are already div]g5t1 /ill m s4 ,by ! assi/ance ( su* glasses1 !re=e1 ! rays f a di/ant object1 fall on ! pupil1 z div]g5t z ^? f a less di/ant object2 &1 ) %ort-sight$ p1 !y ?r[ ! image ( a di/ant object1 back1 z f> z ! ret9a4 ,c>ol9e4 ,?is is an excell5t contrivance1 inde$4 ,mrs4 ,b4 ,& tell me1 :at rem$y w\ld y devise = su* p]sons z h a contr>y defect 9 _! sight2 t is to say1 :o are long-sight$1 9 :om ! cry/all9e hum\r1 be+ too flat1 does n refract ! rays suffici5tly1 s t !y rea* ! ret9a be=e !y are conv]g$ to a po9t8 ,c>ol9e4 ,i suppose t a contr>y rem$y mu/ be appli$ to ?is defect2 t is to say1 a convex l5s1 ,l ,m1 fig4 #b1 to make up = ! defici5cy ( convexity ( ! cry/all9e hum\r1 ,o ,p4 ,= ! convex l5s w\ld br+ ! rays ne>] toge!r1 s t !y w\ld fall1 ei!r less div]g5t1 or p>allel1 on ! cry/all9e hum\r2 &1 by be+ soon] conv]g$ to a focus1 w\ld fall on ! ret9a4 ,mrs4 ,b4 ,v well1 ,c>ol9e4 ,?is is ! reason :y eld]ly p1 ! hum\rs ( ^: eyes are decay$ by age1 are "u ! necessity ( us+ convex spectacles4 ,& :5 depriv$ ( t res\rce1 !y hold ! object at a di/ance f _! eyes1 z 9 fig4 #c1 9 ord] to br+ ! focus m =w>d4 ,c>ol9e4 ,i h (t5 be5 surpris$1 :5 my gr&fa!r reads )\t 8 spectacles1 to see him hold ! book at a consid]able di/ance f 8 eyes4 ,b ,i n[ und]/& ! cause2 ! m di/ant ! object is f ! cry/all9e l5s1 ! ne>] to x1 w ! image be =m$4 ,emily4 ,i compreh5d ! nature ( ^! two opposite defects v well2 b ,i _c n[ conceive1 h[ any sight c be p]fect3 =1 if ! cry/all9e hum\r is ( a prop] degree ( convexity1 to br+ ! image ( di/ant objects to a focus on ! ret9a1 x w n repres5t ne> objects di/9ctly2 & if1 on ! contr>y1 x is adapt$ to give a cle> image ( ne> objects1 x w produce a v imp]fect "o1 ( di/ant objects4 ,mrs4 ,b4 ,y\r obs]vation is v good1 ,emily2 & x is true1 t e p]son w\ld be subject to "o ( ^! two defects1 if we _h x n 9 our p[] to adapt ! eye1 to ! di/ance ( ! object2 x is believ$ t ?is is accompli%$1 by our hav+ a comm& ov] ! cry/all9e l5s1 s z to project x t[>ds1 or draw x back f ! object1 z circum/ances require1 by means ( ! two muscles1 to :i* ! cry/all9e hum\r is atta*$2 s t ! focus ( ! rays1 con/antly falls on ! ret9a1 & an image is =m$ equally di/9ct1 ei!r ( di/ant objects1 or ( ^? :i* are ne>4 ,c>ol9e4 ,9 ! eyes ( fi%es1 :i* are ! only eyes ,i h ev] se5 sep>ate f ! head1 ! cornea does n protrude1 9 t "p ( ! eye :i* is expos$ to view4 ,mrs4 ,b4 ,! cornea ( ! eye ( a fi% is n m convex ?an ! re/ ( ! ball ( ! eye2 b to supply ?is defici5cy1 _! cry/all9e hum\r is sph]ical1 & refracts ! rays s mu*1 t x does n require ! assi/ance ( ! cornea to br+ !m to a focus on ! ret9a4 ,emily4 ,pray1 :at is ! reason t we _c see an object di/9ctly1 if we place x v ne> to ! eye8 ,mrs4 ,b4 ,because ! rays fall on ! cry/all9e hum\r1 too div]g5t to be refract$ to a focus on ! ret9a2 ! confusion1 !re=e1 aris+ f view+ an object too ne> ! eye1 is simil> to t :i* proce$s f a flatt5$ cry/all9e hum\r2 ! rays rea* ! ret9a be=e !y are collect$ to a focus1 7fig4 #d47 ,if x 7 n = ?is imp]fection1 we %\ld be able to see & di/+ui% ! p>ts ( objects1 :i*1 f _! m9ut5ess1 are n[ invisible to u2 =1 c\ld we place !m v ne> ! eye1 ! image on ! ret9a w\ld be s mu* magnifi$1 z to r5d] !m visible4 ,emily4 ,& c\ld !re be no contrivance1 to convey ! rays ( objects view$1 close to ! eye1 s t !y %\ld be refract$ to a focus on ! ret9a8 ,mrs4 ,b4 ,! microscope is con/ruct$ = ?is purpose4 ,! s+le microscope 7fig4 #e47 consi/s simply ( a convex l5s1 commonly call$ a magnify+ glass2 9 ! focus ( :i* ! object is plac$1 & ?r\gh :i* x is view$3 by ?is means1 y are enabl$ to place y\r eye v ne> to ! object1 = ! l5s ,a ,b1 by dim9i%+ ! div]g5ce ( ! rays1 be=e !y ent] ! pupil ,c1 makes !m fall p>allel on ! cry/all9e hum\r ,d1 by :i* !y are refract$ to a focus on ! ret9a1 at ,r ,r4 ,emily4 ,?is is a mo/ admirable inv5tion1 & no?+ c be m simple2 = ! l5s magnifies ! object1 m]ely by all[+ u to br+ x ne>] to ! eye4 ,illu/ration3 ,,plate ,,xxiii4 ,mrs4 ,b4 ,^? l5ses1 !re=e1 :i* h ! %orte/ focus w magnify ! object mo/1 because !y enable u to place x ne>e/ to ! eye4 ,emily4 ,b a l5s1 t has ! %orte/ focus1 is mo/ bulg+ or convex2 & ! protub]ance ( ! l5s w prev5t ! eye f approa*+ v ne> to ! object4 ,mrs4 ,b4 ,?is is rem$i$ by mak+ ! l5s extremely small3 x may !n be sph]ical )\t occupy+ mu* space1 & ?us unite ! advantages ( a %ort focus1 & ( all[+ ! eye to approa* ! object4 ,!re is a mode ( magnify+ objects1 )\t ! use ( a l5s3 if y look ?r\gh a hole1 n l>g] ?an a small p91 y may place a m9ute object ne> to ! eye1 & x w be di/9ct1 & greatly enl>g$4 ,?is piece ( t9 has be5 p]=at$ = ! purpose2 place x close to y\r eye1 & ?is small pr9t be=e x4 ,c>ol9e4 ,a/oni%+6 ! lett]s appe> t5 times z l>ge z !y d )\t x3 ,i _c conceive h[ ?is effect is produc$4 ,mrs4 ,b4 ,! smallness ( ! hole1 prev5ts ! entrance into ! eye1 ( ^? p>ts ( e p5cil ( rays :i* div]ge mu*2 s t1 not)/&+ ! ne>ness ( ! object1 ^? rays f x1 :i* ent] ! eye1 are ne>ly p>allel1 & are1 !re=e1 br\ght to a focus by ! hum\rs ( ! eye4 ,c>ol9e4 ,we h a microscope at home1 :i* is a mu* m complicat$ in/rum5t ?an t y h describ$4 ,mrs4 ,b4 ,x is a d\ble microscope1 7fig4 #f47 9 :i* y see1 n ! object ,a ,b1 b a magnifi$ image ( x1 a b4 ,9 ?is microscope1 two l5ses are employ$2 ! "o1 ,l ,m1 = ! purpose ( magnify+ ! object1 is call$ ! object-glass1 ! o!r1 ,n ,o1 acts on ! pr9ciple ( ! s+le microscope1 & is call$ ! eye-glass4 ,!re is ano!r k9d ( microscope1 call$ ! sol> microscope1 :i* is ! mo/ wond]ful f its great magnify+ p[]3 9 ?is we also view an image =m$ by a l5s1 n ! object itself4 ,z ! sun %9es1 ,i c %[ y ! effect ( ?is microscope2 b = ?is purpose1 we mu/ close ! %utt]s1 & admit only a small portion ( light1 ?r\gh ! hole 9 ! w9d[-%utt]1 :i* we us$ = ! cam]a obscura4 ,we %all n[ place ! object ,a ,b1 7plate #bc1 fig4 #a47 :i* is a small insect1 be=e ! l5s ,c ,d1 & ne>ly at its focus3 ! image ,e ,f1 w !n be repres5t$ on ! opposite wall1 9 ! same mann]1 z ! l&scape 0 9 ! cam]a obscura2 ) ?is diff]5ce1 t x w be magnifi$1 in/ead ( be+ dim9i%$4 ,i %all leave y to acc\nt = ?is1 by exam9+ ! figure4 ,emily4 ,i see x at once4 ,! image ,e ,f is magnifi$1 because x is f>!r f ! l5s1 ?an ! object ,a ,b2 :ile ! repres5tation ( ! l&scape 0 dim9i%$1 because x 0 ne>] ! l5s1 ?an ! l&scape 04 ,a l5s1 !n1 answ]s ! purpose equally well1 ei!r = magnify+ or dim9i%+ objects8 ,mrs4 ,b4 ,yes3 if y wi% to magnify ! image1 y place ! object ne> ! focus ( ! l5s2 if y wi% to produce a dim9i%$ image1 y place ! object at a di/ance f ! l5s1 9 ord] t ! image may be =m$ 91 or ne> ! focus4 ,c>ol9e4 ,! magnify+ p[] ( ?is microscope is prodigi\s3 b ! indi/9ctness ( ! image1 = want ( light1 is a great imp]fection4 ,w\ld x n be cle>]1 if ! op5+ 9 ! %utt] 7 enl>g$1 s z to admit m light8 ,mrs4 ,b4 ,if ! :ole ( ! light admitt$1 does n fall ^u ! object1 ! effect w only be to make ! room light]1 & ! image consequ5tly less di/9ct4 ,emily4 ,b c\ld y n by means ( ano!r l5s1 br+ a l>ge p5cil ( rays to a focus on ! object1 & ?us conc5trate ^u x ! :ole ( ! light admitt$8 ,mrs4 ,b4 ,v well4 ,we %all enl>ge ! op5+1 & place ! l5s ,x ,y 7fig4 #b47 9 x1 to conv]ge ! rays to a focus on ! object ,a ,b4 ,!re is b "o ?+ m want+ to complete ! sol> microscope1 :i* ,i %all leave to ,c>ol9e's sagacity to discov]4 ,c>ol9e4 ,our microscope has a small mirror atta*$ to x1 ^u a moveable jo9t1 :i* c be s adju/$ z to receive ! sun's rays1 & reflect !m ^u ! object3 if a simil> mirror 7 plac$ to reflect light ^u ! l5s1 w\ld x n be a means ( illum9at+ ! object m p]fectly8 ,mrs4 ,b4 ,y are q "r4 ,p ,q 7fig4 #b47 is a small mirror1 plac$ on ! outside ( ! w9d[-%utt]1 :i* receives ! incid5t rays ,s ,s1 & reflects !m on ! l5s ,x ,y4 ,n[ t we h complet$ ! app>atus1 let u exam9e ! mites on ?is piece ( *eese1 :i* ,i place ne> ! focus ( ! l5s4 ,c>ol9e4 ,oh1 h[ mu* m di/9ct ! image n[ is1 & h[ wond]fully magnifi$6 ,! mites on ! *eese look l a drove ( pigs scrambl+ ov] rocks4 ,emily4 ,i nev] saw any ?+ s curi\s4 ,n[1 an imm5se piece ( *eese has fall53 "o might imag9e x an e>?quake3 "s ( ! poor mites mu/ h be5 cru%$2 h[ fa/ !y run--!y absolutely seem to gallop4 ,b ?is microscope c be us$ only = transp>5t objects2 z ! light mu/ pass ?r\gh !m1 to =m ! image on ! wall8 ,mrs4 ,b4 ,v m9ute objects1 su* z are view$ 9 a microscope1 are g5]ally transp>5t1 b :5 opaque objects are to be exhibit$1 a mirror ,m ,n 7fig4 #c47 is us$ to reflect ! light on ! side ( ! object next ! wall3 ! image is !n =m$ by light reflect$ f ! object1 in/ead ( be+ transmitt$ ?r\gh x4 ,emily4 ,pray1 is n a magic lan?orn con/ruct$ on ! same pr9ciples8 ,mrs4 ,b4 ,yes1 ) ?is diff]5ce2 ! objects to be magnifi$1 are pa9t$ ^u pieces ( glass1 & ! light is suppli$ by a lamp1 in/ead ( ! sun4 ,! microscope is an excell5t inv5tion to enable u to see & di/+ui% objects1 :i* are too small to be visible to ! nak$ eye4 ,b !re are objects1 :i*1 ?\gh n really small1 appe> s to u1 f _! di/ance2 to ^!1 we _c apply ! same rem$y2 = :5 a h\se is s f> di/ant1 z to be se5 "u ! same angle z a mite :i* is close to u1 ! effect produc$ on ! ret9a is ! same3 ! angle x subt5ds is n l>ge en\gh = x to =m a di/9ct image on ! ret9a4 ,emily4 ,s9ce x is impossible1 9 ?is case1 to make ! object approa* ! eye1 _c we by means ( a l5s br+ an image ( x1 ne>] to u8 ,mrs4 ,b4 ,yes2 b !n ! object be+ v di/ant f ! focus ( ! l5s1 ! image w\ld be too small to be visible to ! nak$ eye4 ,emily4 ,!n1 :y n look at ! image ?r\gh ano!r l5s1 :i* w act z a microscope1 enable u to br+ ! image close to ! eye1 & ?us r5d] x visible8 ,mrs4 ,b4 ,v well1 ,emily2 ,i congratulate y on hav+ inv5t$ a telescope4 ,9 figure #d1 ! l5s ,c ,d1 =ms an image ,e ,f1 ( ! object ,a ,b2 & ! l5s ,x ,y1 s]ves ! purpose ( magnify+ t image2 & ?is is all t is requir$ 9 a common refract+ telescope4 ,emily4 ,b 9 fig4 #d1 ! image is n inv]t$ on ! ret9a1 z objects usually are3 x %\ld !re=e appe> to u inv]t$2 & t is n ! case 9 ! telescopes ,i h look$ ?r\gh4 ,mrs4 ,b4 ,:5 x is necess>y to repres5t ! image erect1 two o!r l5ses are requir$2 by :i* means a second image is =m$1 ! rev]se ( ! fir/1 & consequ5tly upright4 ,^! additional glasses are us$ to view t]re/rial objects2 = no inconv5i5ce arises f see+ ! cele/ial bodies inv]t$4 ,emily4 ,! diff]5ce betwe5 a microscope & a telescope1 seems to be ?is3--a microscope produces a magnifi$ image1 because ! object is ne>e/ ! l5s2 & a telescope produces a dim9i%$ image1 because ! object is fur!/ f ! l5s4 ,mrs4 ,b4 ,y\r obs]vation applies only to ! l5s ,c ,d1 or object-glass1 :i* s]ves to br+ an image ( ! object ne>] ! eye2 = ! l5s ,x ,y1 or eye-glass1 is1 9 fact1 a microscope1 z its purpose is to magnify ! image4 ,:5 a v great magnify+ p[] is requir$1 telescopes are con/ruct$ ) concave mirrors1 in/ead ( l5ses4 ,^! are call$ reflect+ telescopes1 because ! image is reflect$ by metallic mirrors4 ,concave mirrors1 y "k1 produce by reflection1 an effect simil> to t ( convex l5ses1 by refraction4 ,9 reflect+ telescopes1 !re=e1 mirrors are us$ 9 ord] to br+ ! image ne>] ! eye2 & a l5s1 or eye-glass1 ! same z 9 ! refract+ telescope1 to magnify ! image4 ,! advantage ( ! reflect+ telescope is1 t mirrors ^: focus is six feet1 w magnify z mu* z l5ses ( a hundr$ feet3 an in/rum5t ( ?is k9d may1 !re=e1 possess a high magnify+ p[]1 & yet be s %ort1 z to be readily manag$4 ,c>ol9e4 ,b ,i ?\ght x 0 ! eye-glass only :i* magnifi$ ! image2 & t ! o!r l5s1 s]v$ to br+ a dim9i%$ image ne>] to ! eye4 ,mrs4 ,b4 ,! image is dim9i%$ 9 comp>ison ) ! object1 x is true2 b x is magnifi$1 if y comp>e x to ! dim5sions ( :i* x w\ld appe> )\t ! int]v5tion ( any optical in/rum5t2 & ?is magnify+ p[] is great] 9 reflect+1 ?an 9 refract+ telescopes4 ,we mu/ n[ br+ our obs]vations to a conclusion1 = ,i h communicat$ to y ! :ole ( my v limit$ /ock ( k ( ,natural ,philosophy4 ,if x enable y to make fur!r progress 9 t sci5ce1 my wi%es w be satisfi$2 b rememb]1 9 ord] t ! /udy ( nature may be productive ( happ9ess1 x mu/ lead to an entire confid5ce 9 ! wisdom & goodness ( its b\nte\s ,au?or4 ,que/ions #a4 7,pg4 #aie7 ,:at is ! =m ( ! body ( ! eye8 fig4 #a1 plate #ba4 #b4 7,pg4 #aie7 ,:at is its ext]nal coat call$8 #c4 7,pg4 #aie7 ,:at is ! transp>5t "p ( ?is coat d5om9at$8 #d4 7,pg4 #aie7 ,:at is ! second coat nam$8 #e4 7,pg4 #aie7 ,:at op5+ is !re 9 ?is8 #f4 7,pg4 #aie7 ,:at is ! col\r$ "p :i* surr\nds ! pupil8 #g4 7,pg4 #aie7 ,! pupils dilate & contract1 :at purpose does ?is answ]8 #h4 7,pg4 #aif7 ,h[ c\ld y obs]ve ! dilatation & contraction ( ! pupils8 #i4 7,pg4 #aif7 ,:at purpose is ! *oroid said to answ]8 #aj4 7,pg4 #aif7 ,9 :at animals is ! *ange 9 ! iris greate/8 #aa4 7,pg4 #aif7 ,:at are ! ?ree hum\rs d5om9at$1 & h[ are !y situat$8 #ab4 7,pg4 #aig7 ,:at is ! "p repres5t$ at i i1 & ( :at does x consi/8 #ac4 7,pg4 #aig7 ,:at are ! respective uses ( ! hum\rs1 & ( ! ret9a8 #ad4 7,pg4 #aig7 ,:y is x necess>y ! rays %\ld be refract$8 #ae4 7,pg4 #aig7 ,h[ is ?is illu/rat$ by fig4 #c & #d1 plate #ba8 #af4 7,pg4 #aih7 ,:at causes a p]son to be %ort-sight$8 fig4 #e1 plate #ba4 #ag4 7,pg4 #aih7 ,:y does plac+ an object ne> ! eye1 enable su*1 to see di/9ctly8 fig4 #f4 #ah4 7,pg4 #aii7 ,a concave l5s rem$ies ?is defect2 h[8 fig4 #a1 plate #bb4 #ai4 7,pg4 #aii7 ,:at is ! rem$y1 :5 a p]son is long-sight$8 fig4 #b4 #bj4 7,pg4 #aii7 ,:y does hold+ an object f> f ! eye1 help su* p]sons8 fig4 #c4 #ba4 7,pg4 #bjj7 ,h[ is ! eye said to adapt itself to di/ant1 & to ne> objects8 #bb4 7,pg4 #bjj7 ,:y are objects r5d]$ indi/9ct1 :5 plac$ v ne> to ! eye8 fig4 #d1 plate #bb4 #bc4 7,pg4 #bjj7 ,:at is ! s+le microscope1 fig4 #e1 & h[ does x magnify objects8 #bd4 7,pg4 #bja7 ,h[ may objects be magnifi$ )\t ! aid ( a l5s8 #be4 7,pg4 #bja7 ,:y c an object1 v ne> to ! eye1 be di/9ctly se51 :5 view$ ?r\gh a small hole8 #bf4 7,pg4 #bja7 ,describe ! d\ble microscope1 z repres5t$ 9 fig4 #f1 plate #bb4 #bg4 7,pg4 #bjb7 ,h[ does ! sol> microscope1 7fig4 #a plate #bc47 op]ate8 #bh4 7,pg4 #bjb7 ,:y may m9ute objects be greatly magnifi$ by ?is in/rum5t8 #bi4 7,pg4 #bjb7 ,9 its m p]fect =m x has o!r app5dages1 z se5 9 fig4 #b1 :at are !y8 & :at _! uses8 #cj4 7,pg4 #bjc7 ,:at is add$ :5 opaque objects are to be view$8 fig4 #c4 #ca4 7,pg4 #bjc7 ,9 :at does ! magic lan?orn diff] f ! sol> microscope8 #cb4 7,pg4 #bjc7 ,:at are ! use & /ructure ( ! telescope1 z %[n 9 fig4 #d8 #cc4 7,pg4 #bjd7 ,:5 t]re/rial objects are to be view$1 :y are two additional l5ses employ$8 #cd4 7,pg4 #bjd7 ,:at "p ( ! telescope p]=ms ! "p ( a microscope8 #ce4 7,pg4 #bjd7 ,9 :at does ! reflect+1 diff] f ! refract+ telescope8 #cf4 7,pg4 #bjd7 ,:at advantages1 d reflect+1 possess ov] refract+ telescopes8 ,,gloss>y4 ,,accel]at$ ,,motion4 ,motion is said to be accel]at$1 :5 ! velocity is cont9ually increas+4 ,,accid5tal ,,prop]ties4 ,^? prop]ties ( bodies :i* are liable to *ange1 z col\r1 =m1 c4 ,,acute4--,see ,,angle4 ,,air4 ,an ela/ic fluid4 ,! atmosph]e :i* surr\nds ! e>?1 is g5]ally und]/ood by ?is t]m1 b !re are _m k9ds ( air4 ,! t]m is synonym\s ) ,gas4 ,,air ,,pump4 ,an in/rum5t by :i* vessels may be exhau/$ ( air4 ,,altitude4 ,! height 9 degrees ( ! sun1 or any heav5ly body1 above ! horizon4 ,,angle4 ,! space conta9$ betwe5 two l9es incl9$ to ea* o!r1 & :i* meet 9 a po9t4 ,angles are measur$ 9 degrees1 ^u a segm5t ( a circle describ$ by plac+ "o leg ( a pair ( compasses on ! angul> po9t1 & ) ! o!r1 describ+ ! segm5t betwe5 ! two l9es4 ,if ! segm5t be exactly #a-d? ( a circle1 x is call$ a "r angle1 & conta9s #ij deg4 ,if m ?an #a-d? ( a circle1 x is an obtuse angle4 ,if less1 an acute angle4 ,see plate #b4 ,,angle ,,( ,,incid5ce1 is ! space conta9$ betwe5 a ray :i* falls obliquely ^u a body1 & a l9e p]p5dicul> to ! surface ( ! body1 at ! po9t :]e ! ray falls4 ,,angle ,,( ,,reflection4 ,! space conta9$ betwe5 a reflect$ ray1 & a l9e p]p5dicul> to ! reflect+ po9t4 ,,angle ,,( ,,vision1 or visual angle4 ,! space conta9$ betwe5 l9es drawn f ! extreme p>ts ( any object1 & meet+ 9 ! eye4 ,,ant>ctic ,,circle4 ,a circle ext5d+ r\nd ! s\? pole1 at ! di/ance ( #bc #a-b degrees f x4 ,! same z ! s\? frigid zone4 ,,aphelion4 ,t "p ( ! orbit ( a planet1 9 :i* its di/ance f ! sun is ! greate/4 ,,area4 ,! surface enclos$ betwe5 ! l9es :i* =m ! b\nd>y ( any figure1 :e!r regul> or irregul>4 ,,aries4 ,see ,,sign4 ,,a/]oids4 ,! "n giv5 to ! f\r small planets1 ,c]es1 ,juno1 ,pallas1 & ,ve/a4 ,,a/ronomy4 ,! sci5ce :i* treats ( ! motion & o!r ph5om5a ( ! sun1 ! planets1 ! />s1 & ! o!r heav5ly bodies4 ,,atmosph]e4 ,! air :i* surr\nds ! e>?1 ext5d+ to an unkn[n height4 ,w9d is ?is air 9 motion4 ,,attraction4 ,a t5d5cy 9 bodies to approa* ea* o!r1 & to exi/ 9 contact4 ,,attraction ,,( ,,cohesion4 ,t attraction :i* causes matt] to rema9 9 masses1 prev5t+ !m f fall+ into p[d]4 ,= ?is attraction to exi/1 ! p>ticles mu/ be contigu\s4 ,,attraction ,,( ,,gravitation4 ,by ?is attraction1 masses ( matt]1 plac$ at a di/ance1 h a t5d5cy to approa* ea* o!r4 ,attraction is mutual betwe5 ! sun & ! planets4 ,,axis ,,( ,,! ,,e>?1 ,,or ,,( ,,any ,,( ,,! ,,planets4 ,an imag9>y l9e pass+ ?r\gh _! c5tres1 & t]m9at+ at _! poles2 r\nd ?is _! diurnal revolutions are p]=m$4 ,,axis ,,( ,,motion4 ,! imag9>y l9e1 ar\nd :i* all ! p>ts ( a body revolve1 :5 x has a sp9n+ motion4 ,,axis ,,( ,a ,,l5s1 ,,or ,,mirror4 ,a l9e pass+ ?r\gh ! c5tre ( a l5s1 or mirror1 9 a direction p]p5dicul> to its surface4 ,,balloon4 ,any holl[ globe4 ,! t]m is g5]ally appli$ to ^? :i* are made to asc5d 9 ! air4 ,,b>omet]4 ,commonly call$ a wea!r-glass4 ,x has a glass tube1 conta9+ quicksilv]1 :i* by ris+ & fall+1 indicates any *ange 9 ! pressure ( ! atmosph]e1 & ?us frequ5tly w>ns u ( *anges 9 ! wea!r4 ,,body4 ,! same z ,matt]4 ,x may exi/ 9 ! solid1 liquid1 or a]i=m /ate2 & includes e ?+ ) :i* we become acqua9t$ by ! aid ( ! s5ses4 ,,burn+-,,glass1 ,,or ,,mirror4 ,a l5s1 or a mirror1 by :i* ! rays ( light1 & heat1 are br\ght to a focus1 s z to set bodies on fire4 ,,cam]a ,,obscura1 a d>k5$ room2 or m frequ5tly a box1 admitt+ light by "o op5+1 :]e a l5s is plac$2 :i*1 br++ ! rays ( light1 f ext]nal objects1 to a focus1 pres5ts a p]fect picture ( !m1 9 m9iature4 ,,capill>y ,,tubes4 ,tubes1 ! bore ( :i* is v small4 ,glass tubes are usually employ$1 to %[ ! ph5om5on ( capill>y attraction4 ,fluids 9 :i* !y are imm]s$1 rise 9 su* tubes above ! level ( t 9 ! conta9+ vessel4 ,,c5tre ,,( ,a ,,circle4 ,a po9t1 equally di/ant f e "p ( its circumf]5ce4 ,,c5tre ,,( ,,gravity4 ,t po9t )9 a body1 to :i* all its p>ticles t5d1 & ar\nd :i* !y exactly balance ea* o!r4 ,a sy/em ( bodies1 z ! planets1 may h a common c5tre ( gravity1 ar\nd :i* !y revolve 9 _! orbits2 :il/ ea*1 l ! e>?1 has its p>ticul> c5tre ( gravity )9 itself4 ,,c5tre ,,( ,,motion4 ,t po9t ab\t :i* ! p>ts ( a revolv+ body move1 :i* po9t is1 itself1 consid]$ z 9 a /ate ( re/4 ,,c5tre ,,( ,,magnitude4 ,! middle po9t ( any body4 ,suppose a globe1 "o side ( :i* is =m$ ( lead1 & ! o!r ( wood1 ! c5tres ( magnitude & ( gravity1 w\ld n be 9 ! same po9ts4 ,,c5tral ,,=ces4 ,^? :i* ei!r impel a body t[>ds1 or f1 a c5tre ( motion4 ,,c5trifugal4 ,t :i* gives a t5d5cy to fly f a c5tre4 ,,c5tripetal4 ,t :i* impels a body1 t[>ds a c5tre4 ,,circle4 ,a figure2 ! p]iph]y1 or circumf]5ce ( :i*1 is e :]e equally di/ant1 f ! po9t1 call$ its c5tre4 ,,circle1 ,,great4 ,on ! globe1 or e>?1 is "o t divides x into two equal p>ts1 or hemisph]es4 ,! equator1 & m]idian l9es1 are great circles4 ,,circle1 ,,less]4 ,^? :i* divide ! globe into unequal p>ts4 ,! tropical1 arctic & ant>ctic circles1 & all p>allels ( latitude1 are less] circles4 ,,circumf]5ce4 ,! b\nd>y l9e ( any surface1 z t :i* surr\nds ! c5tre ( a circle2 ! f\r sides ( a squ>e1 c4 ,,comets4 ,bodies :i* revolve r\nd ! sun1 9 v long ovals1 approa*+ him v ne>ly 9 _! p]ihelion1 b 9 _! aphelion1 pass+ to a di/ance immeasurably great4 ,,cohesion4 ,see ,,attraction4 ,,compressible4 ,capable ( be+ =c$ into a small] space4 ,,concave4 ,holl[$ out2 ! inn] surface ( a wat*-glass is concave1 & may repres5t ! =m ( a concave mirror1 or l5s4 ,,convex4 ,project+1 or bulg+ out1 z ! ext]ior surface ( a wat*-glass1 :i* may repres5t ! =m ( a convex mirror1 or l5s4 ,,cone4 ,a body some:at resembl+ a sug>-loaf2 t is1 hav+ a r\nd base1 & slop+ at ! sides1 until x t]m9ates 9 a po9t4 ,,conjunction4 ,:5 ?ree ( ! heav5ly bodies are 9 a /raight or "r l9e1 if y take ei!r ( ! extreme bodies1 ! o!r two are 9 conjunction ) x2 because a /raight l9e drawn f x1 might pass ?r\gh ! c5tres ( bo?1 & jo9 !m toge!r4 ,at ! "t ( new moon1 ! moon & sun are 9 conjunction ) ! e>?2 & ! moon & e>?1 are 9 conjunction ) ! sun4 ,,con/ellation1 ,,or ,,sign4 ,a collection ( />s4 ,a/ronom]s h imag9$ pictures drawn 9 ! heav5s1 s z to embrace a numb] ( contigu\s />s1 & h nam$ ! gr\p aft] ! animal1 or o!r article suppos$ to be drawn2 an individual /> is g5]ally designat$ by its fanci$ location2 z ^u ! e> ( ,leo1 ! ,lion1 c4 ,,conv]g5t ,,rays1 are ^? :i* approa* ea* o!r1 s z ev5tually to meet 9 ! same po9t4 ,,cry/als4 ,bodies ( a regul> =m1 hav+ flat surfaces1 & well def9$ angles4 ,nitre1 & o!r salts1 are famili> examples4 ,_m masses ( matt]1 are compos$ ( cry/als too m9ute to be disc]n$ )\t glasses4 ,,curvil9e>1 consi/+ ( a l9e :i* is n /raight1 z a portion ( a circle1 ( an oval1 or any curv$ l9e4 ,,cyl9d]4 ,a body 9 ! =m ( a roll]1 hav+ flat circul> ends1 & be+ ( equal diamet] ?r\gh\t4 ,,degree4 ,if a circle ( any size be divid$ into #cfj equal p>ts1 ea* ( ^! p>ts is call$ a degree4 ,"o qu>t] ( a circle conta9s n9ety degrees2 "o twelf? ( a circle1 ?irty degrees4 ,! actual l5g? ( a degree1 mu/ dep5d ^u ! size ( ! circle4 ,a degree ^u ! equator1 ^u a m]idian1 or any great circle ( ! e>?1 is equal to #fi-a_/b miles4 ,/raight l9es are sometimes divid$ into equal p>ts1 call$ degrees2 b ^! divisions are arbitr>y1 be>+ no relation%ip to ! degrees ^u a circle4 ,,d5sity4 ,clos5ess ( texture4 ,:5 two bodies are equal 9 bulk1 t :i* weighs ! mo/1 has ! greate/ d5sity4 ,,diagonal4 ,a l9e drawn s z to connect two remote angles ( a squ>e1 or o!r f\r-sid$ figure4 ,,dilatation4 ,! act ( increas+ 9 size4 ,bodies 9 g5]al1 dilate :5 heat$1 & contract by cool+4 ,,discord4 ,:5 ! vibrations ( ! air1 produc$ by two musical tones1 d n be> a c]ta9 ratio to ea* o!r1 a j>r+ s\nd is produc$1 :i* is call$ discord4 ,,div]g5t ,,rays4 ,^? :i* proce$ f ! same po9t1 b are cont9ually rec$+ f ea* o!r4 ,,divisibility4 ,capability ( be+ divid$1 or ( hav+ ! p>ts sep>at$ f ea* o!r4 ,?is is call$ "o ( ! ess5tial prop]ties ( matt]2 because1 h[ev] m9ute ! p>ticles may be1 !y mu/ /ill conta9 z _m halves1 qu>t]s1 c4 z ! l>ge/ mass ( matt]4 ,,e*o4 ,a s\nd reflect$ back1 by "s sub/ance1 s situat$ z to produce ?is effect4 ,,eclipse4 ,! int]ruption ( ! light ( ! sun1 or ( "s o!r heav5ly body1 by ! int]v5tion ( an opaque body4 ,! moon pass+ betwe5 ! e>? & ! sun1 causes an eclipse ( ! latt]4 ,,ecliptic4 ,a circle 9 ! heav5s4 ,! app>5t pa? ( ! sun1 ?r\gh ! twelve signs ( ! zodiac4 ,?is is caus$ by ! actual revolution ( ! e>?1 r\nd ! sun4 ,x is call$ ! ecliptic1 because eclipses always happ5 9 ! direction ( t l9e1 f ! e>?4 ,,ela/icity4 ,t prop]ty ( bodies1 by :i* !y resume _! dim5sions & =m1 :5 ! =ce :i* *ang$ !m is remov$4 ,air is em95tly ela/ic4 ,two ivory balls1 /ruck toge!r1 become flatt5$ at ! po9t ( contact2 b imm$iately resum+ _! =m1 !y react ^u ea* o!r4 ,,ellipsis4 ,an oval4 ,?is figure diff]s f a circle1 9 be+ unequal 9 its diamet]s1 & 9 hav+ two c5tres1 or po9ts1 call$ its foci4 ,! orbits ( ! planets are all elliptical4 ,,equator4 ,t imag9>y l9e :i* divides ! e>? into nor!rn & s\!rn hemisph]es1 & :i* is equally di/ant f ea* pole4 ,,equilibrium4 ,:5 two articles exactly balance ea* o!r1 !y are 9 equilibrium4 ,!y may1 not)/&+1 be v unequal 9 weight1 b !y mu/ be s situat$1 t1 if set 9 motion1 _! mom5tums w\ld be equal4 ,,equ9ox4 ,! two p]iods ( "t at :i* ! nights & days are e :]e ( equal l5g?4 ,! v]nal equ9ox is 9 ,m>*1 :5 ! sun ent]s ! sign ,aries2 ! autumnal equ9ox 9 ,septemb]1 :5 ! sun ent]s ,libra4 ,at ^! p]iods1 ! sun is v]tical at ! equator4 ,,exhalations4 ,all ^? articles :i* arise f ! e>?1 & mix+ ) ! atmosph]e1 =m vap\r4 ,,expansion4 ,! same z dilatation1 :i* see4 ,,ext5sion4 ,"o ( ! ess5tial prop]ties ( matt]2 t by :i* x occupies "s space1 to ! exclusion ( all o!r matt]4 ,,figure4 ,all matt] mu/ exi/ 9 "s =m1 or %ape2 h5ce figure is deem$ an ess5tial prop]ty ( matt]4 ,,fluid4 ,a =m ( matt]1 9 :i* its p>ticles readily fl[1 or slide1 ov] ea* o!r4 ,airs1 or gases1 are call$ ela/ic fluids1 because !y are readily r$uc$ to a small] bulk by pressure4 ,liquids1 are d5om9at$ non-ela/ic fluids1 because !y suff] b little dim9ution ( bulk1 by any me*anical =ce4 ,,focus4 ,t po9t 9 :i* conv]g+ rays unite4 ,,=ce4 ,t p[] :i* acts ^u a body1 ei!r t5d+ to create1 or to /op motion4 ,,f\nta94 ,a jet1 or /ream ( wat]1 =c$ upw>ds by ! weight ( o!r wat]1 by ! ela/icity ( air1 or "s o!r me*anical pressure4 ,,friction4 ,! rubb+ ( bodies toge!r1 by :i* _! motion is ret>d$4 ,friction may be less5$1 b _c be de/roy$4 ,,frigid ,,zones4 ,! spaces or areas1 conta9$ )9 ! arctic & ant>ctic circles4 ,,fulcrum4 ,a prop4 ,! po9t or axis1 by :i* a body is support$1 & ab\t :i* x is susceptible ( motion4 ,,gas4 ,any k9d ( air2 ( ^! !re are sev]al4 ,! atmosph]e consi/s ( two k9ds1 mix$1 or comb9$ ) ea* o!r4 ,,geometry4 ,t bran* ( ! ma!matics1 :i* treats ( l9es1 ( surfaces1 & ( solids2 & inve/igates _! prop]ties1 & proportions4 ,,globe4 ,a sph]e1 or ball4 ,x has a po9t 9 its c5tre ( magnitude1 f :i* its surface is e :]e equally di/ant4 ,,gravity4 ,t species ( attraction :i* appe>s to be common to matt]1 exi/+ 9 its p>ticles1 & giv+ to !m1 & ( c\rse to ! masses :i* !y compose1 a t5d5cy to approa* ea* o!r4 ,by gravity a /one falls to ! e>?1 & by x ! heav5ly bodies t5d t[>ds ea* o!r4 ,,h>mony4 ,a comb9ation ( musical s\nds1 produc$ by vibrations :i* be> a c]ta9 ratio to ea* o!r2 & :i* !nce affect ! m9d agreeably1 :5 he>d at ! same "t4 ,s\nds n s relat$1 produce discord4 ,,hemisph]e4 ,half a sph]e or globe4 ,a plane pass+ ?r\gh ! c5tre ( a globe1 w divide x into hemisph]es4 ,,horizon4 ,?is is g5]ally divid$ into s5sible1 & rational4 ,! s5sible horizon is t portion ( ! surface ( ! e>?1 to :i* our vision ext5ds4 ,our rational horizon is t circle 9 ! heav5s :i* b\nds our vision1 :5 on ! ocean1 an ext5d$ plane1 or any elevat$ situation4 ,9 ! heav5s our s5sible1 & our rational horizon are ! same2 its plane w\ld divide ! e>? into hemisph]es at #ij degrees f u2 & a p]son /&+ on t "p ( ! e>? :i* is directly opposite to u1 w\ld1 at ! same mom5t1 see 9 8 horizon1 ! same heav5ly bodies1 :i* w\ld be se5 9 ours4 ,,horizontal4 ,level2 n incl9$1 or slop+4 ,a p]fectly r\nd ball1 plac$ ^u a flat surface1 :i* is plac$ horizontally1 w rema9 at re/4 ,,hydraulics4 ,t sci5ce :i* treats ( wat] 9 motion1 & ! means ( rais+1 conduct+1 & us+ x = mov+ ma*9]y1 or o!r purposes4 ,,hydro/atics4 ,treats ( ! weight1 pressure1 & equilibrium ( fluids1 :5 9 a /ate ( re/4 ,,hydromet]4 ,an in/rum5t us$ to asc]ta9 ! specific gravity ( diff]5t fluids1 :i* x does1 by ! dep? to :i* x s9ks :5 float+ on !m4 ,,image4 ,! picture ( any object :i* we p]ceive ei!r by reflect$ or refract$ light4 ,all objects :i* are visible1 become s by =m+ images on ! ret9a4 ,,imp5etrability4 ,t prop]ty ( matt]1 by :i* x excludes all o!r matt] f occupy+ ! same space ) itself at ! same "t4 ,if two p>ticles c\ld exi/ 9 ! same space1 s also might any great] numb]1 & inde$ all ! matt] 9 ! univ]se1 might be collect$ 9 a s+le po9t4 ,,incid5ce4 ,! direction 9 :i* a body1 or a ray ( light1 moves 9 its approa* t[>ds any sub/ance1 ^u :i* x /rikes4 ,,incl9$ ,,plane4 ,"o ( ! six me*anical p[]s4 ,any plane surface incl9$ to ! horizon1 may be s d5om9at$4 ,,in]tia4 ,"o ( ! inh]5t prop]ties ( matt]4 ,want ( p[]1 or ( any active pr9ciple )9 itself1 by :i* x c *ange its own /ate1 :e!r ( motion1 or ( re/4 ,,inh]5t ,,prop]ties4 ,^? prop]ties :i* are absolutely necess>y to ! exi/5ce ( a body2 call$ also ess5tial prop]ties4 ,all o!rs are d5om9at$ accid5tal4 ,col\r is an accid5tal--ext5sion1 an ess5tial prop]ty ( matt]4 ,,latitude4 ,di/ance f ! equator1 9 a direct l9e t[>ds ei!r pole4 ,?is di/ance is measur$ 9 degrees & m9utes4 ,! degree ( latitude _c exce$ n9ety1 or "o qu>t] ( a circle4 ,places to ! s\? ( ! equator1 are 9 s\? latitude1 & ^? to ! nor?1 9 nor? latitude4 ,,latitude1 ,,p>allels ,,(4 ,l9es drawn ^u ! globe1 p>allel to ! equator1 are s call$2 e place situat$ on su* a l9e1 has ! same latitude1 because equally di/ant f ! equator4 ,,l5s4 ,a glass1 gr\nd s t "o or bo? surfaces =m segm5ts ( a sph]e1 s]v+ ei!r to magnify1 or dim9i% objects se5 ?r\gh !m4 ,glasses us$ 9 spectacles are l5ses4 ,,lev]4 ,"o ( ! me*anical p[]s4 ,an inflexible b> ( wood or metal1 support$ by a fulcrum1 or prop2 & employ$ to increase ! effect ( a giv5 p[]4 ,,libra4 ,"o ( ! twelve signs ( ! zodiac4 ,t into :i* ! sun ent]s1 at ! autumnal equ9ox4 ,,light4 ,t pr9ciple1 by ! aid ( :i* we are able to disc]n all visible objects4 ,x is g5]ally believ$ to be a sub/ance emitt$ by lum9\s bodies1 &1 excit+ vision by pass+ into ! eye4 ,,longitude4 ,di/ance measur$ 9 degrees & m9utes1 ei!r 9 an ea/]n1 or a we/]n direction1 f any giv5 po9t ei!r on ! equator1 or on a p>allel ( latitude4 ,degrees ( longitude may am\nt to #ahj1 or half a circle4 ,a degree ( longitude measur$ ^u ! equator1 is ( ! same l5g? ) a degree ( latitude2 b z ! poles are approa*$1 ! degrees ( longitude dim9i% 9 l5g?1 because ! circles ^u :i* !y are measur$1 become less4 ,,lun>4 ,relat+ to ,luna1 ! moon4 ,,lunation4 ,! "t 9 :i* ! moon completes its circuit4 ,a lun> mon?4 ,,lum9\s ,,bodies4 ,^? :i* emit light f _! own sub/ance2 n %9+ by borr[$1 or reflect$ light4 ,,ma*9e4 ,any in/rum5t1 ei!r simple or comp\nd1 by :i* any me*anical effect is produc$4 ,a ne$le1 & a clock1 are bo? ma*9es4 ,,magic ,,lan?orn1 ,,or ,,lant]n4 ,an optical in/rum5t1 by :i* transp>5t pictures1 pa9t$ ^u glass1 are magnifi$ & exhibit$ on a :ite wall or scre51 9 a d>k5$ room4 ,! phantasmagoria1 is a species ( magic lan?orn4 ,,ma!matics4 ,! sci5ce ( numb]s & ( ext5sion4 ,common ari?metic1 is a l[] bran* ( ! ma!matics4 ,9 its high] dep>tm5ts1 x ext5ds to e ?+ :i* is capable ( be+ ei!r numb]$ or measur$4 ,,matt]4 ,sub/ance4 ,e ?+ ) :i* we become acqua9t$ by ! aid ( ! s5ses2 e ?+ h[ev] l>ge1 or h[ev] m9ute1 :i* has l5g?1 bread?1 & ?ickness4 ,,me*anics4 ,t sci5ce :i* inve/igates ! pr9ciples1 ^u :i* ! action ( e ma*9e dep5ds2 & tea*es _! prop] application 9 ov]com+ resi/ance1 & 9 produc+ motion1 9 all ! useful purposes to :i* !y are appli$4 ,,m$ium4 ,9 optics1 is any body :i* transmits light4 ,air1 wat]1 glass1 & all o!r transp>5t bodies1 are m$ia4 ,m$ium also d5otes t 9 :i* any body moves4 ,air is ! m$ium :i* conveys s\nd1 & :i* enables birds to fly4 ,,melody4 ,a succession ( su* s+le musical s\nds1 z =m a simple air or tune4 ,,m]cury4 ,t planet :i* is ne>e/ to ! sun4 ,quicksilv]1 a metal1 :i* rema9s fluid at ! common temp]ature ( ! atmosph]e4 ,x is capable ( be+ r5d]$ solid1 by int5se cold4 ,,m]idian4 ,midday4 ,a m]idian l9e1 is "o :i* ext5ds directly f "o pole ( ! e>? to ! o!r2 cross+ ! equator at "r angles4 ,x is !re=e half ( a great circle4 ,! h\r ( ! day is ! same at e place situat$ on ! same m]idian4 ,longitude is measur$ f any giv5 m]idian1 to ! opposite m]idian4 ,places at ! same di/ance 9 degrees1 to ! ea/ or we/ ( any m]idian1 h ! same longitude4 ,,microscope4 ,an optical in/rum5t1 by :i* m9ute objects1 are magnifi$1 s z to enable u to p]ceive & exam9e su* z c\ld n be se5 by ! nak$ eye4 ,,m9]al4 ,e>?s1 /ones1 metals1 salts1 & 9 g5]al all sub/ances dug out ( ! e>?1 are d5om9at$ m9]als4 ,,m9ute4 ,9 "t1 ! sixtie? "p ( an h\r4 ,9 l5g?1 ! sixtie? "p ( a degree4 ,a m9ute ( "t1 is an unv>y+ p]iod2 b a m9ute 9 l5g? v>ies 9 ext5t1 ) ! degree ( :i* x =ms a "p4 ,! degrees & m9utes are equal 9 numb]1 ^u a common r+1 ^u ! equator ( ! e>?1 or1 on any circle ( ! heav5s4 ,,mirrors4 ,poli%$ surfaces ( metal1 or ( glass coat$ ) metal1 = ! purpose ( reflect+ ! rays ( light1 & ! images ( objects4 ,common look+-glasses1 are mirrors4 ,^? us$ 9 reflect+ telescopes1 are made ( metal4 ,,mobility4 ,capable ( be+ mov$ f "o place to ano!r4 ,?is is acc\nt$ "o ( ! ess5tial prop]ties ( matt]1 because we _c conceive ( its exi/5ce )\t ?is capacity4 ,,mom5tum4 ,! =ce1 or p[]1 ) :i* a body 9 motion acts ^u any o!r body1 or t5ds to pres]ve its own quantity ( motion4 ,! mom5tum ( a body1 is comp\nd$ ( its quantity ( matt]1 & its velocity4 ,a body weigh+ "o p\nd1 mov+ ) a velocity ( two miles 9 a m9ute1 w possess ! same mom5tum ) "o weigh+ two p\nds1 mov+ ) a velocity ( "o mile 9 a m9ute4 ,,motion4 ,a cont9u$ & successive *ange ( place1 ei!r ( a :ole body1 or ( ! p>ticles ( :i* a body is compos$2 ! e>? 9 revolv+ ^u its axis only1 w\ld n *ange its place z a body1 b all ! p>ticles ( :i* x is compos$1 w\ld revolve r\nd a common axis ( motion4 ,9 revolv+ 9 its orbit1 its :ole mass is con/antly occupy+ a new portion ( space4 ,,natural ,,philosophy4 ,t sci5ce :i* enquires into ! laws :i* gov]n all ! natural bodies 9 ! univ]se1 9 all _! *anges ( place1 or ( /ate4 ,,neap ,,tides4 ,^? tides :i* occur :5 ! moon is 9 h] quadratures1 or half way betwe5 new1 & full moon2 at ^! p]iods ! tides are ! l[e/4 ,,nodes4 ,^? po9ts 9 ! orbit ( ! moon1 or ( a planet1 :]e x crosses ! ecliptic or plane ( ! e>?'s orbit4 ,:5 pass+ to ! nor? ( ! ecliptic1 x is call$ ! asc5d+ node2 :5 to ! s\? ( x1 ! desc5d+ node4 ,,oblate4 ,see ,,sph]oid4 ,,octagon4 ,a figure ) eight sides1 & consequ5tly ) eight angles4 ,,opaque4 ,n transp>5t2 refus+ a passage to ! rays ( light4 ,,optics4 ,t bran* ( sci5ce :i* treats ( light1 & vision4 ,x is g5]ally divid$ into two p>ts4 ,catoptrics1 :i* treats ( ! reflection ( light1 & ,dioptrics1 :i* treats ( its refraction4 ,,orbit4 ,! l9e 9 :i* a prim>y planet moves 9 its revolution r\nd ! sun2 or a second>y planet1 9 its revolution r\nd its prim>y4 ,^! orbits are all elliptical1 or oval4 ,,p>abola4 ,a p>ticul> k9d ( curve2 t :i* a body describes 9 ris+ & 9 fall+1 :5 ?r[n upw>ds1 9 any direction n p]p5dicul> to ! horizon4 ,,p>allelogram4 ,a figure ) f\r sides1 hav+ ^? :i* are opposite1 p>allel to ea* o!r4 ,a squ>e1 an oblong squ>e1 & ! figure usually call$ a diamond1 are ,p>allelograms4 ,,p>allel ,,l9es4 ,all l9es1 :e!r /raight or curv$1 :i* are e :]e at an equal di/ance f ea* o!r1 are p>allel l9es4 ,,p>allel ,,( ,,latitude4 ,see ,,latitude4 ,,p]ihelion4 ,t "p ( ! orbit ( a planet1 9 :i* x approa*es ! sun mo/ ne>ly4 ,,p5dulum4 ,a body susp5d$ by a rod1 or l9e1 s t x may vibrate1 or oscillate1 backw>ds & =w>ds4 ,p5dulums ( ! same l5g?1 p]=m _! vibrations 9 ! same "t1 :atev] may be _! weight1 & :e!r ! arc ( vibration1 be long or %ort4 ,,p]cussion4 ,! /rik+ ( bodies aga9/ ea* o!r4 ,! =ce ( ?is1 dep5ds ^u ! mom5tum ( ! /rik+ body4 ,,p]iod4 ,! "t requir$ = ! revolution ( "o ( ! heav5ly bodies 9 its orbit4 ,,p]p5dicul>4 ,mak+ an angle ( #ij degrees ) ! horizon4 ,:5 two l9es :i* meet1 make an angle ( #ij degrees1 !y are p]p5dicul> to ea* o!r4 ,,phases4 ,! v>i\s appe>ances ( ! disc1 or face ( ! moon1 & ( ! planets2 t portion ( !m :i* we see illum9at$ by ! rays ( ! sun4 ,,ph5om5on4 ,any natural appe>ance is prop]ly s call$2 ! t]m1 h[ev]1 is usually appli$ to extraord9>y appe>ances1 z eclipses1 transits1 c4 ,,pi/on4 ,t "p ( a pump1 or o!r eng9e :i* is made to fit into a holl[ cyl9d]1 or b>rel2 & to move up & d[n 9 x1 9 ord] to raise wat]1 or = any o!r purpose4 ,,plane4 ,a p]fectly flat surface4 ,! plane ( ! orbit ( a planet1 is an imag9>y flat surface1 ext5d+ to e "p ( ! orbit4 ,,planet4 ,^? bodies :i* revolve r\nd ! sun1 9 orbits ne>ly circul>4 ,!y are divid$ into prim>y1 & second>y2 ^! latt] are also call$ satellites1 or moons2 !y revolve r\nd ! prim>y planets1 & accompany !m 9 _! c\rses r\nd ! sun4 ,,plumb-,,l9e4 ,a /r+1 or cord1 by :i* a weight is susp5d$2 x is us$ = ! purpose ( f9d+ a l9e p]p5dicul> to ! horizon2 ! weight be+ always attract$ t[>ds ! c5tre ( ! e>?4 ,,pneumatics4 ,t bran* ( natural philosophy1 :i* treats ( ! me*anical prop]ties ( ! atmosph]e1 or ( air 9 g5]al4 ,,poles4 ,! extremities ( ! axis ( motion ei!r ( our e>?1 or ( any o!r revolv+ sph]e4 ,! poles ( ! e>? h nev] be5 visit$2 ! regions by :i* !y are surr\nd$1 be+ ob/ruct$ by impassable b>ri]s ( ice4 ,,p[]4 ,t =ce :i* we apply to any me*anical in/rum5t1 to effect a giv5 purpose1 is d5om9at$ p[]1 f :atev] s\rce x may be d]iv$4 ,we h ! p[] ( weights1 ( spr+s1 ( horses1 ( m51 ( /eam1 c4 ,,prism4 ,! in/rum5t usually s call$1 is employ$ 9 optics to decompose ! sol> ray3 x consi/s ( a piece ( solid glass1 sev]al in*es 9 l5g?1 & hav+ ?ree flat sides2 ! ends are equal 9 size1 & are ( c\rse triangul>4 ,,precession ,,( ,,! ,,equ9oxes4 ,e equ9ox takes place a few seconds ( a degree1 be=e ! e>? arrives at t "p ( ! ecliptic 9 :i* ! prec$+ equ9ox occurr$4 ,?is ph5om5on is call$ ! precession ( ! equ9oxes4 ,!re is consequ5tly a gradual *ange ( ! places ( ! signs ( ! zodiac3 a fact1 ! discov]y ( :i* has ?r[n mu* light on anci5t *ronology4 ,,projection4 ,t =ce by :i* motion is giv5 to a body1 by "s p[] act+ ^u x1 indep5d5tly ( gravity4 ,,pulley4 ,"o ( ! six me*anical p[]s4 ,a :eel turn+ ^u an axis1 ) a l9e pass+ ov] x4 ,x is ! moveable pulley only1 :i* gives any me*anical advantage4 ,,pump4 ,an hydraulic1 or pneumatic in/rum5t1 = ! purpose ( rais+ wat]1 or exhau/+ air4 ,,quadrant4 ,a qu>t] ( a circle4 ,an in/rum5t us$ to measure ! elevation ( a body 9 degrees above ! horizon4 ,,quadratures ,,( ,,! ,,moon4 ,t p]iod 9 :i* %e appe>s 9 ! =m ( a semicircle4 ,%e is !n ei!r 9 h] fir/1 or h] la/ qu>t]2 & exactly half way1 betwe5 ! places ( new1 & ( full moon4 ,,radiation4 ,! passage ( light or heat 9 rays1 or /raight l9es2 ^! be+ project$ f e lum9\s1 or heat$ po9t1 9 all directions4 ,,radius4 ,! di/ance f ! c5tre ( a circle1 to its circumf]5ce2 or "o half ( its diamet]4 ,9 ! plural d5om9at$ radii4 ,,ra9b[4 ,an appe>ance 9 ! atmosph]e1 occasion$ by ! decomposition ( sol> light1 9 its refraction1 & reflection1 9 pass+ ?r\gh drops ( ra94 ,! b[ c be se51 only :5 ! sun is ne> ! horizon1 :5 ! back is turn$ t[>ds x1 & !re is a %[] 9 ! opposite direction4 ,,ray4 ,a s+le l9e ( light1 emitt$ 9 "o direction1 f any lum9\s po9t4 ,,reaction4 ,e body1 :e!r 9 a /ate ( motion1 or at re/1 t5ds to rema9 9 su* /ate1 & resi/s ! action ( any o!r body ^u x1 ) a =ce equal to t action4 ,?is resi/ance1 is call$ its reaction4 ,,receiv]4 ,?is "n is appli$ to glass vessels ( v>i\s k9ds1 app]ta9+ to ! air pump1 & f :i* ! air may be exhau/$4 ,!y are made to conta91 or receive1 any article ^u :i* an effect is to be produc$1 by tak+ (f ! pressure ( ! atmosph]e4 ,,refraction1 ( ! rays ( light1 is ! b5d+ ( ^? rays1 :5 !y pass obliquely f "o m$ium into ano!r ( diff]5t d5sity4 ,a /ick held obliquely 9 wat]1 appe>s b5t or brok5 at ! surface ( ! fluid4 ,,refrangibility4 ,capacity ( be+ refract$4 ,light is decompos$ by ! prism1 because its compon5t p>ts are refrangible 9 diff]5t degrees1 by ! same refract+ m$ium4 ,,repulsion4 ,! rev]se ( attraction4 ,a t5d5cy 9 p>ticles1 or 9 masses ( matt]1 to rec$e f ea* o!r4 ,! matt] ( heat )9 a body1 appe>s to c\nt]act ! attraction ( its p>ticles1 s z to prev5t absolute contact4 ,,ret9a4 ,t "p ( ! ball ( ! eye1 ^u :i* ! images ( visible objects are =m$2 & f :i*1 ! idea ( su* =ms1 is convey$ to ! m9d4 ,,revolution1 ( a planet2 is ei!r diurnal1 or annual2 ! =m]1 is its turn+ ^u its own axis2 ! latt]1 is its passage 9 its orbit4 ,,satellites4 ,moons1 second>y planets4 ,,segm5t ,,( ,a ,,circle4 ,a portion1 or "p ( a circle2 call$ also1 an arc ( a circle4 ,,semi-,,diamet]4 ,half ! diamet]4 ,! semi-diamet] ( ! e>?1 is ! di/ance f its surface1 to its c5tre4 ,,sid]ial4 ,belong+ to ! />s4 ,a sid]ial day1 is ! "t requir$ = a /> to reappe> on a giv5 m]idian4 ,a sid]ial ye>1 ! p]iod 9 :i* ! sun appe>s to h travell$ r\nd ! ecliptic1 s z to h arriv$ opposite to any p>ticul> />1 f :i* 8 c\rse 0 calculat$4 ,,signs1 or ,,con/ellations4 ,collections1 or gr\ps1 ( />s4 ,^? ( ! zodiac are twelve1 correspond+ ) ! twelve mon?s 9 ! ye>4 ,9 ! c5tre ( ^! ! ecliptic is situat$4 ,! sun appe>s to pass 9 succession ?r\gh ^! signs2 ent]+ ! fir/ degree ( ,aries1 :i* is acc\nt$ ! fir/ sign1 ab\t ! #ba/ ( ,m>*4 ,,sky4 ,t va/ expanse1 or space1 9 :i* ! heav5ly bodies are situat$4 ,its blue appe>ance is suppos$ to arise f ! p>ticles ( :i* ! atmosph]e is compos$1 possess+ ! prop]ty ( reflect+ ! blue rays1 9 greate/ abundance4 ,,sol>4 ,app]ta9+ to1 or gov]n$ by1 ! sun3 z ! sol> sy/em1 ! sol> ye>1 sol> eclipses4 ,,solid4 ,n fluid4 ,hav+ its p>ts connect$ s z to =m a mass4 ,solid bodies1 are n absolutely s1 all und\bt$ly conta9+ pores1 or spaces void ( matt]4 ,,sol/ices4 ,! middle ( summ] & ! middle ( w9t]2 ^? two po9ts 9 ! orbit ( ! e>?1 9 :i* its poles po9t mo/ directly t[>ds ! sun4 ,,sonor\s ,,bodies4 ,^? bodies :i* are capable ( be+ put into a /ate ( vibration1 s z to emit s\nds4 ,,specific ,,gravity4 ,! relative weight ( bodies ( diff]5t species1 :5 ! same bulk ( ea* is tak54 ,wat] has be5 *os5 z ! /&>d = comp>ison4 ,if we say t ! specific gravity ( a body is #f1 we mean1 t its weight is six times z great z t ( a portion ( wat]1 exactly equal to x 9 bulk4 ,,spectrum4 ,t appe>ance ( diff]5tly col\r$ rays1 :i* is produc$ by ! refraction ( ! sol> ray1 by means ( a prism1 is call$ ! prismatic spectrum2 x exhibits mo/ di/9ctly1 & beautifully1 all ! col\rs se5 9 ! ra9b[4 ,,sph]e4 ,a globe1 or ball4 ,,sph]oid4 ,sph]ical2 a body approa*+ ne>ly to a sph]e 9 its figure4 ,! e>?1 is d5om9at$ an oblate sph]oid2 x n be+ an exact sph]e1 b flatt5$ at ! poles1 s z to cause ! pol> diamet] to be upw>ds ( ?irty miles less ?an ! equatorial4 ,oblate1 is ! rev]se ( oblong1 & means %ort] 9 "o direction1 ?an 9 ano!r4 ,,spr+ ,,tides4 ,^? tides :i* occur at ! "t ( new1 or ( full moon4 ,! tides !n rise to a great] height ?an at any o!r p]iod4 ,,squ>e4 ,a figure hav+ f\r sides ( equal l5g?1 & its angles all "r angles4 ,9 numb]s2 ! product ( a numb] multipli$ into itself2 ?us1 ! squ>e ( #c is #i1 & ! squ>e ( #h is #fd4 ,,/>4 ,! fix$ />s are s call$1 because !y reta9 _! relative situations2 :ile ! planets1 by revolv+ 9 _! orbits1 appe> to w&] among/ ! fix$ />s4 ,,subt5d4 ,?is t]m is appli$ to ! measurem5t ( an angle2 :5 ! l9es by :i* x is b\nd$ rec$e b little f ea* o!r1 !y are said to subt5d2 t is1 to be conta9$ "u1 a small angle4 ,,sup]ficies4 ,! surface ( any figure4 ,space ext5d$ 9 l5g? & wid?4 ,,sy/em4 ,! mutual connexion1 & dep5dance ( ?+s1 ^u ea* o!r4 ,! sol>1 or ,cop]nican sy/em1 includes ! sun1 ! planets1 ) _! moons1 & ! comets4 ,,tang5t4 ,a /raight l9e t\*+ ! circumf]5ce ( a circle2 b :i* w\ld n cut (f any portion ( x1 7 x ext5d$ beyond ! t\*+ po9t1 9 bo? directions4 ,,telescope4 ,an in/rum5t by :i* di/ant objects may be di/9ctly se52 ! images ( objects be+ br\ght ne> to ! eye1 & greatly magnifi$4 ,,temp]ate ,,zones4 ,^? portions ( ! surface ( ! e>? situat$ betwe5 #bc-a_/b & #ff-a_/b degrees ( latitude4 ,)9 ^! b\nd>ies1 ! sun is nev] v]tical2 nor does he ev] rema91 dur+ a :ole day1 bel[ ! horizon4 ,,!rmomet]4 ,an in/rum5t = measur+ ! temp]ature ( ! atmosph]e1 or ( o!r bodies4 ,,torrid ,,zone4 ,t portion ( ! e>? :i* ext5ds #bc-a_/b degrees on ea* side ( ! equator1 to ! tropical circles2 )9 ?is limit1 ! sun is v]tical1 twice 9 ! ye>4 ,,transit4 ,m]cury or ,v5us1 are said to transit ! sun1 :5 !y pass betwe5 ! e>? & t lum9>y4 ,!y !n appe> l d>k spots1 ^u ! face ( ! sun4 ,,transp>5t4 ,all[+ ! rays ( light to pass freely ?r\gh4 ,! rev]se ( opaque4 ,glass1 wat]1 air1 c4 are transp>5t bodies4 ,,tropics4 ,two circles on ! globe on ei!r hemisph]e1 at ! di/ance ( #bc-a_/b degrees f ! equator4 ,beyond ^! circles1 ! sun is nev] v]tical3 & ! c\ntries )9 !m1 are d5om9at$ tropical4 ,,twilight4 ,t portion ( ! morn+ or ev5+1 9 :i* ! light ( ! sun is p]ceptible1 al?\gh he is bel[ ! horizon4 ,,vacuum4 ,space void ( matt]4 ,su* is suppos$ to be ! space 9 :i* ! planets revolve4 ,we are said to produce a vacuum1 :5 we exhau/ ! air f a receiv]4 ,,valve4 ,a "p ( a pump1 & ( "s o!r in/rum5ts1 :i* op5s to admit ! passage ( a fluid 9 "o direction1 b closes :5 press$ 9 ! opposite direction1 s z to prev5t ! return ( ! fluid2 a pair ( bell[s is furni%$ ) a valve4 ,,vap\r4 ,exhalations f fluid or solid sub/ances1 g5]ally mix+ ) ! atmosph]e4 ,! mo/ abundant1 is t f wat]4 ,,v]tical4 ,exactly ov] our heads3 n9ety degrees above our horizon4 ,,vibration4 ,! alt]nate motion ( a body1 =w>ds & backw>ds2 sw++1 z a p5dulum4 ,,visual4 ,belong+ to vision2 z ! visual angle1 or t angle =m$ by ! rays ( light :i* ent] ! eye1 f ! extremities ( any object4 ,,undulation4 ,a vibratory1 or wave-l motion communicat$ to fluids4 ,s\nd1 is said to be propagat$ by ! undulatory1 or vibratory motion ( ! air4 ,,w$ge4 ,"o ( ! me*anical p[]s2 ! =m ( ! w$ge is well kn[n4 ,x is ( ext5sive use2 s]v+ to r5d bodies ( great /r5g?1 & to raise enorm\s weights4 ,,:eel ,,& ,,axle4 ,"o ( ! me*anical p[]s1 us$ "u v>i\s modifications4 ,cranes = rais+ weights1 ! :eels & p9ions ( clocks & wat*es1 w9dlasses1 c4 are all applications ( ?is p[]4 ,,zodiac4 ,a broad belt 9 ! heav5s1 ext5d+ ne>ly eight degrees on ea* side ( ! ecliptic2 ! planes ( ! orbits ( all ! planets are includ$ )9 ?is space4 ,?is belt is divid$ into twelve p>ts or signs1 ea* conta9+ #cj degrees4 ,^! signs are3 ,aries2 ! ,ram4 ,taurus2 ! ,bull4 ,gem9i2 ! ,tw9s4 ,canc]2 ! ,crab4 ,leo2 ! ,lion4 ,virgo2 ! ,virg94 ,libra2 ! ,scales4 ,scorpio2 ! ,scorpion4 ,sagitt>ius2 ! ,ar*]4 ,capricornus2 ! ,goat4 ,aqu>ius2 ! ,wat]]4 ,pisces2 ! ,fi%es4 ,! fir/ six are call$ nor!rn signs2 because ! sun is 9 !m1 dur+ t half ( ! ye>1 9 :i* he is v]tical to ! nor? ( ! equator2 ! la/ six1 are call$ s\!rn signs2 because1 dur+ 8 j\rney among !m1 he is v]tical to ! s\? ( ! equator4 ,! sun ent]s ,aries1 at ! "t ( ! v]nal equ9ox2 ,canc]1 at ! summ] sol/ice2 ,libra1 at ! autumnal equ9ox2 & ,capricornus1 at ! w9t] sol/ice4 ,! sun is said to ent] a sign1 :5 ! e>? 9 go+ r\nd 9 its orbit1 ent]s ! opposite sign4 ,?us1 :5 ! sun appe>s 9 ! fir/ degree ( ,libra1 x is 9 consequ5ce ( ! e>? hav+ arriv$ opposite to ! fir/ degree ( ,aries4 ,a l9e !n drawn f ! e>?1 & pass+ ?r\gh ! c5tre ( ! sun1 w\ld1 if ext5d$ to ! fix$ />s1 t\* ! fir/ degree ( ,libra4 ,,zone4 ,! e>? is divid$ into zones1 or belts4 ,see ,,frigid1 ,,temp]ate1 & ,,torrid ,,zones4 ,,index4 ,a4 ,air1 #aa1 #ae1 #bh1 #ej1 #acf4 ,air-pump1 #ca1 #ade4 ,angle1 #dd4 acute1 #dd4 obtuse1 #dd4 "r1 #dd4 ( incid5ce1 #de1 #aed1 #afj1 #agc4 ( reflection1 #de1 #aed1 #afj1 #agc4 visual1 #afh1 #afi1 #agj4 ,angul> velocity1 #aga4 ,ant>ctic circle1 #ib4 ,aphelion1 #ge4 ,arctic circle1 #ib4 ,atmosph]e1 #bh1 #ajd1 #abi1 #acf1 #add1 #aej1 #afc4 col\r (1 #aic4 reflection (1 #aic4 refraction (1 #ahb4 ,attraction1 #aj1 #ad1 #bc1 #be1 #agi4 ( cohesion1 #ae1 #ai1 #aah4 capill>y1 #ah4 ( gravitation1 #ah1 #bc1 #bi1 #gj1 #hj1 #if1 #aaf1 #acf4 ,av5ue1 #agj4 ,auditory n]ve1 #aea4 ,axis1 #gh4 ( motion1 #dh4 ( ! e>?1 #bb1 #ii4 ( mirrors1 #agf4 ( a l5s1 #ahd4 ,b4 ,balloon1 #cj4 ,b>omet]1 #adj4 ,bass1 #aee4 ,bladd]1 #ach4 ,bodies1 #aj4 ela/ic1 #dj4 fall (1 #bc1 #bf1 #cj1 #cf4 lum9\s1 #aeg4 opaque1 #aeg4 sonor\s1 #aeb1 #aee4 transp>5t1 #aeg4 ,bulk1 #af4 ,c4 ,cam]a obscura1 #ahd1 #aig1 #bja4 ,capill>y tubes1 #ah4 ,c5tre1 #dh4 ( gravity1 #dh1 #ea1 #eb1 #aae4 ( magnitude1 #dh1 #ec4 ( motion1 #dh1 #ee1 #aae4 ,c5trifugal =ce1 #di1 #gb1 #ie1 #aae4 ,c5tripetal =ce1 #di1 #gb4 ,c]es1 #hd4 ,circle1 #dd1 #id4 ,circumf]5ce1 #id4 ,cl\ds1 #abi4 ,col\rs1 #bc1 #ahe4 ,comets1 #hf4 ,compression1 #db4 ,concord1 #aee4 ,con/ellation1 #hf4 ,conv]g5t rays1 #age1 #agg4 ,cry/als1 #ab4 ,curvil9e> motion1 #dg1 #gb4 ,cyl9d]1 #eb4 ,d4 ,day1 #gh1 #aje1 #ajf4 ,degrees1 #dd1 #id1 #ii1 #afi1 #agj4 ( latitude1 #id1 #aab4 ( longitude1 #id1 #aab4 ,d5sity1 #af4 ,diagonal1 #dg4 ,diamet]1 #id4 ,discords1 #aee4 ,diurnal1 #gh4 ,div]g5t rays1 #age1 #agg4 ,divisibility1 #aj1 #ab4 ,e4 ,e>?1 #ah1 #gj1 #hd1 #hh1 #ie4 ,e*o1 #aed4 ,eclipse1 #aaj1 #aei4 ,ecliptic1 #hf1 #ib1 #ii4 ,ela/icity1 #da4 ,ela/ic bodies1 #bh1 #dj4 fluids1 #bh1 #da1 #aah1 #acf4 ,ellipsis1 #ge4 ,equ9ox1 #ajj1 #ajg4 precession (1 #ajg4 ,equator1 #ib1 #ii4 ,ess5tial prop]ties1 #aj4 ,exhalations1 #ac4 ,ext5sion1 #aj1 #aa4 ,eye1 #aff1 #aie4 ,f4 ,fall ( bodies1 #bd1 #bg1 #ca4 ,figure1 #aj1 #ab4 ,fluids1 #aah1 #abh4 ela/ic1 #bh1 #da1 #aah1 #acf4 equilibrium (1 #abj1 #abb1 #acb4 non-ela/ic1 #aai4 pressure (1 #aba4 ,fly+1 #dj4 ,focus1 #agf4 ( concave mirrors1 #agg4 ( convex mirrors1 #age1 #agg4 ( a l5s1 #ahd4 imag9>y1 #agf4 virtual1 #agf4 ,=ce1 #cc4 c5trifugal1 #di1 #gb1 #ie1 #aae4 c5tripetal1 #di1 #gb4 projectile1 #dg1 #di4 ( gravity1 #dg1 #di4 ,f\nta9s1 #ace4 ,friction1 #fh1 #fi1 #ace4 ,frigid zone1 #ic4 ,fulcrum1 #ed4 ,g4 ,g5]al prop]ties ( bodies1 #aj4 ,georgium ,sidus1 #he4 ,glass1 #ahc4 burn+1 #ahh4 refraction (1 #ahc4 ,gold1 #aai1 #abf4 ,gravity1 #ah1 #bc1 #gh1 #ig4 ,h4 ,h>mony1 #aee4 ,heat1 #af1 #bi1 #ajc4 ,hemisph]e1 #ib1 #ajj4 ,h]s*el1 #he4 ,hydraulics1 #aah4 ,hydromet]1 #abh4 ,hydro/atics1 #aah4 ,i4 ,image on ! ret9a1 #afe1 #agb4 rev]s$1 #afg4 9 pla9 mirror1 #agb4 9 concave d4 #age4 9 convex d4 #age4 ,imp5etrability1 #aj4 ,incl9$ plane1 #ed1 #ff4 ,in]tia1 #aj1 #ad1 #cb4 ,inh]5t prop]ties1 #aj4 ,juno1 #hd4 ,jupit]1 #he4 ,l4 ,lake1 #acc1 #ace4 ,latitude1 #id1 #aab4 ,l5s1 #ahd4 concave1 #ahd4 convex1 #ahd4 m5iscus1 #ahd4 plano-concave1 #ahd4 plano-convex1 #ahd4 ,lev]1 #ed1 #ee4 fir/ k9d1 #eh4 second k9d1 #fj4 ?ird k9d1 #fj4 ,light1 #aeg4 p5cil (1 #aeh4 ( ! moon1 #afb1 #afc4 absorption (1 #ahh4 reflect$1 #afj4 refraction (1 #agi4 ,liquids1 #aah4 ,longitude1 #id1 #aab4 ,lum9\s bodies1 #aeg4 ,lun> mon?1 #ajh4 eclipse1 #aaj4 ,m4 ,ma*9e1 #ed1 #ff4 ,magic lan?orn1 #bjc4 ,m>s1 #hd4 ,matt]1 #aj1 #ac4 ,me*anics1 #cb4 ,m$iums1 #aeg1 #ahj4 ,melody1 #aef4 ,m]cury1 7planet7 #hc1 #he1 #aad4 ,m]cury1 or quicksilv]1 #af1 #adj1 #ada4 ,m]idians1 #ic4 ,microscope1 #bjj4 s+le1 #bjj4 d\ble1 #bjj4 sol>1 #bjb1 #bjc4 ,m9]als1 #ab4 ,m9utes1 #id4 ,mom5tum1 #ch1 #ef4 ,monsoons1 #adi4 ,mon?1 lun>1 #ajh4 ,moon1 #gh1 #gi1 #hj1 #hb1 #he4 ,moonlight1 #afb1 #afc4 ,motion1 #ad1 #cb1 #cf4 accel]at$1 #cf4 axis (1 #dh4 c5tre (1 #dh1 #ee4 comp\nd1 #df4 curvil9e>1 #dg1 #di4 diurnal1 #gh4 p]petual1 #ce4 ret>d$1 #ce4 reflect$1 #dc4 uni=m1 #cd4 ,mirrors1 #agb4 axis (1 #agf4 burn+1 #agg4 concave1 #agd1 #agf1 #bji4 convex1 #agd1 #age4 plane or flat1 #agb4 reflection (1 #agc4 ,n4 ,neap tides1 #aaf4 ,n]ves1 #aff4 auditory1 #aea1 #aff4 olfactory1 #aff4 optic1 #afd1 #aff4 ,night1 #gh4 ,nodes1 #aaj4 ,o4 ,octave1 #aef4 ,od\r1 #ac4 ,opaque bodies1 #aeg1 #aeh4 ,optics1 #aeg4 ,orbit1 #hf4 ,p4 ,pallas1 #hd4 ,p>abola1 #ea4 ,p>allel l9es1 #be4 ,p>allel ( latitude1 #id4 ,pellucid bodies1 #aeg4 ,p5cil ( rays1 #aeh4 ,p5dulum1 #ih4 ,p]ihelion1 #ge4 ,p]p5dicul> l9es1 #be4 ,phases1 #aji4 ,pi/on1 #adc1 #ade4 ,plane1 #ib1 #ic4 ,planets1 #gf1 #ha1 #hc4 ,poles1 #ib1 #ii1 #ajj4 ,pol> />1 #ajj1 #aab4 ,porosity1 #db1 #abf4 ,p[]s1 me*anical1 #ed4 ,projection1 #di1 #ej1 #ga4 ,precession ( equ9oxes1 #ajg4 ,pulley1 #ed1 #fc4 ,pump1 #ca4 suck+ & lift+1 #adc4 =c+1 #add1 #ade4 air1 #ca1 #ade4 ,pupil ( ! eye1 #afd4 ,r4 ,ra91 #ag1 #abi4 ,ra9b[1 #ahh4 ,r>ity1 #af4 ,ray ( light1 #aeh1 #agi4 reflect$1 #afj1 #afa4 incid5t1 #afa4 ,rays1 int]sect+1 #afe4 ,reaction1 #ci4 ,receiv]1 #ca4 ,reflection ( light1 #afj1 #afc4 angle (1 #de1 #afa1 #agc4 ( mirrors1 #agc4 ( plane mirrors1 #agd4 ( concave d4 #agd4 ( convex d4 #agd4 ,reflect$ motion1 #dc4 ,refraction1 #agi1 #ahf4 ( ! atmosph]e1 #ahb4 ( glass1 #ahc4 ( a l5s1 #ahd4 ( a prism1 #ahe4 ,resi/ance1 #ed4 ,ret9a1 #afe4 image on1 #aff4 ,riv]s1 #acd4 ,rivulets1 #aca4 ,s4 ,satellites1 #hj1 #aaa1 #aac4 ,saturn1 #he4 ,scales1 or balance1 #ee4 ,screw1 #ed1 #fg4 ,%ad[1 #aaj1 #aaa4 ,sid]ial "t1 #ajf4 ,sight1 #afe4 ,signs ( ! zodiac1 #hf1 #ic4 ,smoke1 #ad1 #bi4 ,sol> microscope1 #bjb4 ,sol/ice1 #ajj1 #ajb4 ,s\nd1 #aea4 acute1 #aee4 musical1 #aee4 ,space1 #cc4 ,specific gravity1 #abc4 ( air1 #adj4 ,spectrum1 #aij4 ,speak+-trumpet1 #aed4 ,sph]e1 #bf4 ,spr+s1 #acj4 ,spr+ tides1 #aaf4 ,squ>e1 #ha1 #he4 ,/>s1 #gg1 #hf1 #ajb4 ,/orms1 #adg4 ,sub/ance1 #aj4 ,summ]1 #gf1 #ajj4 ,sun1 #ga1 #ge1 #gh1 #afb1 #ahb4 ,swimm+1 #da4 ,syphon1 #acb4 ,t4 ,tang5t1 #di1 #gc4 ,telescope1 #bjc1 #bjd4 reflect+1 #bjd4 refract+1 #bjd4 ,temp]ate zone1 #ib1 #aja4 ,!rmomet]1 #adb4 ,tides1 #aad1 #aaf4 neap1 #aaf4 spr+1 #aaf4 a]ial1 #aej4 ,"t1 #aje1 #ajg4 sid]ial1 #ajg4 equal1 #ajg4 sol>1 #ajg4 ,tone1 #aee4 ,torrid zone1 #ic1 #adg1 #ahb4 ,transit1 #aad4 ,transp>5t bodies1 #aeg4 ,treble & bass1 #aee4 ,tropics1 #ib4 ,v4 ,valve1 #adc4 ,vap\r1 #ag1 #bi1 #ajd1 #abi4 ,velocity1 #cc1 #eg4 ,v5us1 #hd4 ,ve/a1 #hd4 ,vibration1 #ih1 #aeb4 ,vision1 #afd1 #afh4 ,vision1 angle (1 #afh1 #agj4 d\ble1 #aga4 ,u4 ,undulation1 #aec4 ,unison1 #aee4 ,w4 ,wat]1 #aah1 #acj4 spr+1 #acj4 ra91 #acj4 level (1 #abj4 ,w$ge1 #ed1 #ff4 ,weight1 #bc4 ,:eel & axle1 #ed1 #fe4 ,w9d1 #adf4 trade1 #adg4 p]iodical1 #adh4 ,w9t]1 #gf1 #aja4 ,y4 ,ye>1 #ajg4 sid]ial1 #ajg4 sol>1 #ajg4 ,z4 ,zodiac1 #hf4 ,zone1 #ic4 torrid1 #ic1 #adg1 #ahb4 temp]ate1 #ic1 #aja4 frigid1 #ic1 #ajj4 ,,! ,,end4 ,,to ,,all ,,tea*]s4 ,,s*ool ,,books4 ,,smiley',s ,,geography ,,& ,,atlas1 & ,,sacr$ ,,& ,,anci5t ,,geography ,,= ,,s*ools4 ,! above works w be f\nd useful & v valuable z works ( ref]5ce1 z well z = s*ools4 ,! ,maps1 compos+ ! ,atlases1 w be f\nd equal 9 execution & correctness to ^? on ! mo/ ext5sive scale4 ,! au?or has receiv$ num]\s recomm5dations1 among :i* are ! foll[+3 ,de> ,sir--,i h look$ ov] y\r ,easy ,introduction to ! ,/udy ( ,geography1 toge!r ) y\r ,improv$ ,atlas4 ,i h no hesitation 9 decl>+1 t ,i consid] !m works ( peculi> m]it4 ,!y d hon\r to y\r indu/ry1 rese>*1 & tal5t1 & ,i am satisfi$1 w facilitate ! improvem5t ( ! /ud5t 9 geographical sci5ce4 ,) s5tim5ts ( s9c]e consid]ation1 ,i am y\rs truly1 ,,wm4 ,,/aughton1 ,d4 ,d4 ,presid5t ( ,columbia ,college1 ,di/rict ( ,columbia4 ,,mr4 ,,?omas ,,smiley4 ,philadelphia1 ,sept4 #a1 #ahbc4 99 99 99 99 99 ,extract f ! ,m9utes ( ! ,philadelphia ,academy ( ,tea*]s4 ,novemb] #a1 #ahbc4 ,resolv$ unanim\sly1 ,t ! ,academy ( ,tea*]s highly approve ! sup]ior m]its ( ,mr4 ,smiley's ,easy ,introduction to ! ,/udy ( ,geography1 & ! accompany+ ,atlas1 & cordially recomm5d !m to ! patronage ( ! public4 ,b4 ,,mayo1 ,presid5t4 ,i4 ,i4 ,,hit*cock1 ,secret>y4 ,,! ,,new ,,f$]al ,,calculator1 or ,,s*ol>',s ,,assi/ant4 ,conta9+ ! mo/ concise & accurate ,rules = p]=m+ ! op]ations 9 common ,ari?metic2 toge!r ) num]\s ,examples "u ea* ( ! ,rules1 v>i$ s z to make !m con=mable to almo/ e k9d ( bus9ess4 ,= ! ,use ( ,s*ools & ,c\nt+ ,h\ses4 ,by ,?omas ,t4 ,smiley1 ,tea*]3 au?or ( ,an ,easy ,introduction to ! ,/udy ( ,geography4 ,also1 ( ,sacr$ ,geography = ! ,use ( ,s*ools4 ,among ! num]\s recomm5dations receiv$ to ! "w1 are ! foll[+3 ,,mr4 ,,john ,,grigg4 ,phila4 ,m>* #h1 #ahbe4 ,,sir--,i h exam9$ ) z mu* c>e z my "t w\ld admit1 ,! ,new ,f$]al ,calculator1 by ,?omas ,t4 ,smiley4 ,x appe>s to me to be a treatise on ,ari?metic ( consid]able m]it4 ,!re are p>ts 9 ,mr4 ,smiley's "w :i* are v valuable2 ! rules giv5 by him 9 ,b>t]1 ,loss & ,ga91 & ,ex*ange1 are a great desid]atum 9 a new sy/em or treatise on ,ari?metic1 & r5d]s 8 book sup]ior to any on ! subject n[ 9 use2 & :5 x is consid]$ t ! calculations 9 ! "w are made 9 ,f$]al ,money1 ! only curr5cy n[ kn[n 9 ! ,unit$ ,/ates1 & t appropriate que/ions foll[ ! diff]5t rules1 by :i* ! le>n] c be ex]cis$ z to 8 und]/&+ ( ea* "p z he progresses2 ,i hesitate n to say1 t1 9 my op9ion1 x is em95tly calculat$ to promote in/ruction 9 ! sci5ce on :i* x treats4 ,mr4 ,smiley des]ves ! ?anks ( ! public & ! enc\ragem5t ( tea*]s1 = 8 attempt to simplify & improve ! me?od ( tea*+ ,ari?metic4 ,i am y\rs respectfully1 ,,wm4 ,p4 ,,smi?1 ,preceptor ( ,ma!matics & ,natural ,philosophy1 ,no4 #aeb1 ,s\? ,t5? ,/reet4 99 99 99 99 99 ,,sir--,i h c>efully exam9$ ,! ,new ,f$]al ,calculator1 or ,s*ol>'s ,assi/ant1 by ,?omas ,t4 ,smiley1 on :i* y politely reque/$ my op9ion2 & freely ackn[l$ge t ,i ?9k x bett] calculat$ = ! use ( ! ,unit$ ,/ates s*ools & c\nt+-h\ses ?an any book on ! subject t ,i h se54 ,! au?or's arrangem5t ( ! f\r prim>y rules is1 9 my op9ion1 a judici\s & laudable innovation1 claim+ ! m]it ( improvem5t2 z x br+s toge!r ! rules ne>e/ relat$ 9 _! nature & uses4 ,8 que/ions ^u ! rules ?r\gh\t1 appe> to me to be admirably calculat$ to elicit ! ex]tions ( ! le>n]4 ,b above all1 ! pref]5ce he has giv5 to ! curr5cy ( 8 own c\ntry1 9 its num]\s examples1 has /amp$ a value ^u ?is little "w1 :i* ,i believe has n fall5 to ! lot ( any o!r book ( ! k9d1 z yet (f]$ to ! ,am]ican public4 ,i am1 sir1 y\rs respectfully1 ,,john ,,mackay4 ,*>le/on1 7,s4 ,c47 ,m>* #bi1 #ahbe4 99 99 99 99 99 ,f ! ,unit$ ,/ates ,gazette4 ,among ! num]\s publications ( ! pres5t day1 devot$ to ! improvem5t ( y\?1 we h notic$ a new edition ( ,smiley's ,ari?metic1 j publi%$ by ,j4 ,grigg4 ,! g5]al arrangem5t ( ?is book is an improvem5t ^u ! ,ari?metics 9 pres5t use1 be+ m sy/ematic1 & accord+ to ! aff9ities ( diff]5t rules4 ,! *ief advantage ( ! pres5t ov] ! fir/ edition1 is a correction ( sev]al typographical errors1 a circum/ance :i* w r5d] x peculi>ly acceptable to tea*]s4 ,9 ref]r+ to ! m]its ( ?is little "w1 x is prop] to m5tion t a great] portion ( its pages are devot$ to ,f$]al calculation1 ?an is g5]ally all[$ 9 prim>y works 9 ?is bran* ( /udy4 ,! heavy tax ( "t & pati5ce :i* our y\? are n[ compell$ to pay to ! errors ( _! ance/ors1 by p]=m+ ! v>i\s op]ations ( p\nds1 %ill+s1 & p5ce1 %\ld be remitt$1 & we are glad to notice t ! ,f$]al computation is becom+ ! prom95t practice ( s*ool ari?metic4 ,9 recomm5d+ ,mr4 ,smiley's book to ! notice ( p>5ts & tea*]s1 we believe t we invite _! att5tion to a "w t w really prove an assi/ant to !m1 & a guide to _! int]e/+ *>ge4 99 99 99 99 99 ,! ,editors ( ! ,new ,york ,telegraph1 speak+ ( ,smiley's ,ari?metic1 obs]ve t !y h )9 a few days att5tively exam9$ ! above ,ari?metic1 & say1 ,we d n hesitate to pron\nce x an improvem5t ^u e "w ( ! k9d previ\sly be=e ! public2 & z su*1 recomm5d its adoption 9 all our ,s*ools & ,academies4 ,a ,,key to ! above ,ari?metic1 9 :i* all ! ,examples necess>y = a ,le>n] are wr\ght at l>ge1 & also ,solutions giv5 ( all ! v>i\s ,rules4 ,design$ pr9cipally to facilitate ! lab\r ( ,tea*]s1 & assi/ su* z h n ! opportunity ( a tutor's aid4 ,by ,t4 ,t4 ,smiley1 au?or ( ! ,new ,f$]al ,calculator1 c4 c4 ,,torrey',s ,,spell+ ,,book1 or ,fir/ ,book = ,*ildr54 ,i h exam9$ ,mr4 ,jesse ,torrey's ,famili> ,spell+ ,book4 ,i ?9k x a great improvem5t 9 ! primitive1 & n lea/ important bran*es ( education1 & %all introduce x into ! sem9>ies "u my c>e1 z "o sup]ior to any :i* has yet appe>$4 ,,ira ,,hill1 ,a4 ,m4 ,boonsbor\gh1 ,feb4 #b1 #ahbe4 ,! increas+ dem& = ?is "w is ! be/ evid5ce ( its m]its4 ,a ,,pleas+ ,,companion ,,= ,,little ,,girls ,,& ,,boys1 bl5d+ ,in/ruction ) ,amusem5t2 be+ a ,selection ( ,int]e/+ ,/ories1 ,dialogues1 ,fables1 & ,poetry4 ,design$ = ! use ( ,prim>y ,s*ools & ,dome/ic ,nurs]ies4 ,by ,jesse ,torrey1 ,jr4 ,to secure ! p]petuation ( our republican =m ( gov]nm5t to future g5]ations1 let ,div9es & ,philosoph]s1 ,/atesm5 & ,patriots1 unite _! endeav\rs to r5ovate ! age1 by impress+ ! m9ds ( ! p ) ! importance ( educat+ _! little boys & girls4 ,s4 ,,adams4 ,report ( ! ,committee ( ! ,philadelphia ,academy ( ,tea*]s3 adopt$ ,nov4 #f1 #ahbd4 ,! ,committee1 to :om 0 ref]r$ ,mr4 ,jesse ,torrey's ,pleas+ ,companion = ,little ,girls & ,boys1 beg leave to report1 ,t !y h p]us$ ! ,pleas+ ,companion1 & h mu* pleasure 9 pron\nc+ z _! op9ion1 t x is a compilation mu* bett] calculat$ = ! ex]cise & improvem5t ( small *ildr5 9 ! art ( read+1 & especially 9 ! m r>e art ( und]/&+ :at !y read1 ?an ! books 9 g5]al use4 ,all :i* is respectfully submitt$4 ,i4 ,,irv9e ,,hit*cock1 ,,p>don ,,davis1 ,,*>les ,,mead1 ,committee4 ,a true copy f ! m9utes ( ! ,academy4 ,c4 ,b4 ,,trego1 ,secret>y4 ,nov4 #bb1 #ahbd4 ,,! ,,moral ,,in/ructor ,,& ,,guide ,,to ,,virtue1 by ,jesse ,torrey1 ,jr4 ,among ! num]\s recomm5dations to ?is valuable ,s*ool ,book1 are ! foll[+3-- ,extract ( a note f ! ,hon4 ,?omas ,jeff]son1 late ,presid5t ( ! ,unit$ ,/ates4 ,i ?ank y1 sir1 = ! copy ( y\r ',moral ,in/ructor4' ,i h read ! fir/ edition ) great satisfaction1 & enc\rag$ its read+ 9 my family4 99 99 99 99 99 ,extracts ( a ,lett] f ! ,hon4 ,james ,madison1 late ,presid5t ( ! ,unit$ ,/ates4 ,sir--,i h receiv$ y\r lett] ( ! #ae?1 ) a copy ( ! ,moral ,in/ructor4 ,i h look$ en\gh into y\r little volume to be satisfi$1 t bo? ! orig9al & select$ p>ts conta9 in=mation & in/ruction :i* may be useful1 n only to juv5ile b mo/ o!r read]s4 ,) fri5dly respects1 ,,james ,,madison4 ,,dr4 ,,torrey4 99 99 99 99 99 ,f ,rob]ts ,vaux1 ,presid5t ( ! ,controll]s ( ! ,public ,s*ools 9 ,philadelphia4 ,! ,moral ,in/ructor is a valuable compilation4 ,x appe>s to be well adapt$ = elem5t>y s*ools1 & x w give me pleasure to le>n t ! lessons :i* x conta9s are furni%$ = ! improvem5t ( our y\? g5]ally4 ,respectfully1 ,,rob]ts ,,vaux4 ,philadelphia1 #e? mon?1 #h #ahbc4 ,,hi/ory ,,( ,,engl&1 f ! ,fir/ ,invasion by ,julius ,caes>1 to ! ,accession ( ,george ! ,f\r?1 9 eighte5 hundr$ & tw5ty3 compris+ e ,political ,ev5t wor?y ( remembrance2 a ,progressive ,view ( ,religion1 ,language1 & ,mann]s2 ( ,m5 em95t = _! ,virtue or _! ,le>n+2 _! ,patriotism1 ,eloqu5ce1 or ,philosophical ,rese>*2 ( ! ,introduction ( ,manufactures1 & ( ,colonial ,e/abli%m5ts4 ,) an int]rogative ,index1 = ! use ( ,s*ools4 ,by ,william ,grim%aw1 au?or ( a ,hi/ory ( ! ,unit$ ,/ates1 c4 ,,hi/ory ,,( ,,! ,,unit$ ,,/ates1 f _! fir/ settlem5t z ,colonies1 to ! cession ( ,florida1 9 #ahba3 compris+ e ,important ,political ,ev5t2 ) a ,progressive ,view ( ! ,aborig9es2 ,population1 ,religion1 ,agriculture1 & ,comm]ce2 ( ! ,arts1 ,sci5ces1 & ,lit]ature2 occasional ,biographies ( ! mo/ rem>kable ,coloni/s1 ,writ]s1 & ,philosoph]s1 ,w>riors1 & ,/atesm52 & a ,copi\s ,alphabetical ,index4 ,by ,william ,grim%aw1 au?or ( a ,hi/ory ( ,engl&1 c4 ,also1 ,,que/ions adapt$ to ! above ,hi/ory1 & a ,,key1 adapt$ to ! ,que/ions1 = ! use ( ,tea*]s4 ,univ]sity ( ,georgia1 ,a!ns1 ,june #d1 #ahbe4 ,,de> ,,sir1 ,) grateful pleasure1 ,i h read ! two small volumes ( ,mr4 ,grim%aw1 7a ,hi/ory ( ,engl&1 & a ,hi/ory ( ! ,unit$ ,/ates7 :i* y "s "t s9ce plac$ 9 my h&s4 ,on a c>eful p]usal ( !m1 ,i feel no difficulty 9 giv+ my op9ion1 t !y are bo?1 z to /yle & s5tim5t1 works ( uncommon m]it 9 _! k9d2 & admirably adapt$ to excite1 9 y\?ful m9ds1 ! love ( hi/orical rese>*4 ,) s9c]e wi%es = ! success ( 8 lit]>y lab\rs1 ,i am v respectfully1 y\r fri5d1 ,m4 ,,waddel1 ,presid5t4 ,e4 ,,jackson1 ,,esq4 99 99 99 99 99 ,d4 ,,jaudon pres5ts 8 respectful complim5ts to ,mr4 ,grim%aw1 & is mu* oblig$ by 8 polite att5tion1 & ! h&some complim5t ( 8 ,hi/ory ( ! ,unit$ ,/ates ) ! ,que/ions & ,key4 ,mr4 ,j4 has be5 9 ! use ( ?is book = "s "t2 b anticipates /ill m pleasure to himself1 & pr(it to 8 pupils1 9 future1 f ! help & facility :i* ! que/ions & key w af=d 9 ! /udy ( ^! int]e/+ pages4 ,octob] #aj?1 #ahbb4 99 99 99 99 99 ,golgo?a1 ,p4 ,edwd4 ,va4 ,sep4 #bf1 #ahbj4 ,,de> ,,sir1 ,,mr4 ,,grim%aw',s ',hi/ory ( ! ,unit$ ,/ates1' c4 0 "s "t ago put into my h&s by ,mr4 ,b----1 :o reque/$ me to give y my op9ion z to ! m]its ( ! "w4 ,! hi/ory ( ! late w> is well manag$ by y\r au?or3 x has m ( detail & int]e/ ?an ! =m] "p2 & ,i consid] x mu* sup]ior to any ( ! _m compilations on t subject1 ) :i* ! public has be5 fav\r$4 ,x may be said ( ! entire p]=mance1 t x is decid$ly ! be/ *ronological s]ies1 & ! *a/e/ hi/orical n>rative1 suit$ to ! capacity ( ! juv5ile m9d1 t has yet appe>$4 ,its arrangem5t is judici\s2 its /yle neat1 always p]spicu\s1 & (t5 elegant2 & its pr9ciples s\nd4 ,am]ican writ+s on m5 & ?+s connect$ ) ,am]ica1 h be5 long ne$$ = ! "y2 & ,i am happy to f9d1 t ,mr4 ,grim%aw has n only und]tak5 to supply ?is want1 b also to ,am]icanise =eign hi/ory = ! use ( our s*ools4 ,9 a ^w1 sir1 ,i am s fond ( ,am]ican fabrics1 & s anxi\s to %[ myself humbly in/rum5tal 9 giv+ our y\? ,am]ican feel+ & "* :il/ at s*ool2 t ,i %all )\t hesitation recomm5d ,mr4 ,grim%aw's works to my "y pupils1 z introductory to m ext5sive hi/orical read+4 ,9 f9e1 ! "w is s unobjectionable1 & puts s great a mass ( necess>y in=mation )9 ! rea* ( s*ool-boys1 at s *eap a rate1 t ,i feel ! highe/ pleasure 9 recomm5d+ x to ! public1 & wi% y ext5sive sales4 ,y\rs respectfully1 ,,william ,,bran*1 ,,jr4 ,,mr4 ,,b5jam9 ,,w>n]1 ,philadelphia4 99 99 99 99 99 ,hi/ory ( ! ,unit$ ,/ates1 f _! fir/ settlem5t z ,colonies1 to ! ,peace ( ,gh5t1 c4 ,by ,william ,grim%aw1 pp4 #cab1 #abmo4 ,?is is ! ?ird "t1 )9 ! space ( two ye>s1 t we h _h occasion to review a volume f ! h& ( ,mr4 ,grim%aw4 ,he writes ) great rapidity2 & improves z he advances4 ,?is is ! mo/ correctly writt5 ( all 8 productions4 ,we c\ld wi% t a p]son s well =m$ = close1 & p]sev]+ /udy1 z he mu/ be1 might f9d enc\ragem5t to devote himself to ! int]e/s ( lit]ature4 ,mr4 ,g4 has our ?anks = ! be/ concise & compreh5sive hi/ory ( ! ,unit$ ,/ates :i* we h se54 ,!ological ,review1 ,octob]1 #ahai4 99 99 99 99 99 ,hi/ory ( ,engl&1 f ! fir/ ,invasion by ,julius ,caes>1 to ! ,peace ( ,gh5t1 c4 ,= ! use ( ,s*ools4 ,by ,william ,grim%aw4 ,philadelphia1 #ahai4 ,b5jam9 ,w>n]4 #abmo4 pp4 #cjj4 ,we h copi$ s mu* ( ! title ( ?is "w1 b>ely to express our decid$ approbation ( ! book1 & to recomm5d its g5]al introduction into s*ools4 ,x is "o ( ! be/ books ( ! k9d to be f\nd1 & is in/ructive ev5 to an adult read]4 ,we %\ld be pleas$ t tea*]s w\ld rank x among _! class-books2 = x is well calculat$ to give correct impressions1 to its read]s1 ( ! gradual progress ( sci5ce1 religion1 gov]nm5t1 & _m o!r in/itutions1 a k ( :i* is b5eficial 9 ! pres5t age4 ,among ! _m /rik+ m]its ( ?is book1 are1 ! p]spicuity ( ! n>rative1 & *a/5ess ( ! /yle4 ,x is ) no little pleasure we h le>n$1 t ! au?or has prep>$ a simil> hi/ory ( ! ,unit$ ,/ates2 a "w long want$1 to fill up a deplorable *asm 9 ! education ( ,am]ican y\?4 ,analectic ,magaz9e1 ,octob]1 #ahai4 99 99 99 99 99 ,philadelphia1 #bh ,june1 #ahai4 ,,sir--,i h read ) pleasure & pr(it y\r ,hi/ory ( ,engl&4 ,i ?9k x is writt5 ) p]spicuity1 *a/5ess1 & imp>tiality4 ,well writt5 hi/ory is ! be/ political in/ructor1 & "u a gov]nm5t 9 :i* x is ! bless+ ( ! c\ntry t ! p gov]n1 its pages %\ld be con/antly 9 ! h&s ( our y\?1 & lie op5 to ! humble/ citiz5 9 our wide-spread t]ritories4 ,y\r book is em95tly calculat$ ?us to diffuse ?is important k1 & !re=e entitl$ to ext5sive circulation2 :i* ,i mo/ cordially wi%4 ,) mu* respect1 ,y\r ob$i5t s]vant1 ,,langdon ,,*eves4 ,,william ,,grim%aw1 ,,esq4 ,,grim%aw',s ,,improv$ ,,edition ,,( ,,goldsmi?',s ,,greece4--,among ! num]\s recomm5dations to ?is valuable ,s*ool ,book1 are ! foll[+3-- ,al?\gh !re are _m wor?less ,s*ool ,books1 !re are b few :i* are equally impure & inaccurate ) ! orig9al editions ( ,goldsmi?'s ,hi/ories1 = ! use ( ,s*ools4 ,i congratulate bo? tea*]s & pupils ^u ! appe>ance ( ,mr4 ,grim%aw's edition ( ! ,hi/ory ( ,greece1 :i* has be5 s completely expurgat$1 & o!rwise correct$1 z to give x ! "* ( a new "w1 admirably adapt$ to ! purpose = :i* x is int5d$4 ,,?os4 ,p4 ,,jones1 ,pr(essor ( ,me*anics 9 ! ,frankl9 ,in/itute ( ! ,/ate ( ,p5nsylvania1 & late ,pr9cipal ( ! ,nor? ,c>ol9a ,female ,academy4 ,philadelphia1 ,sept4 #e1 #ahbf4 99 99 99 99 99 ,,mr4 ,,john ,,grigg4 ,,de> ,,sir--,agreeably to y\r reque/ ,i h exam9$1 ) att5tion1 ,goldsmi?'s ,greece1 revis$ & correct$1 & a vocabul>y ( prop] names app5d$1 ) prosodial m>ks1 to assi/ 9 _! pronunciation1 by ,william ,grim%aw2 & ,i feel a p]fect fre$om to say1 t ! correction ( num]\s grammatical & o!r errors1 by ,mr4 ,grim%aw1 toge!r ) ! rejection ( _m obsc5e & indelicate passages improp] = ! p]usal ( y\?1 gives ?is edition1 9 my op9ion1 a decid$ pref]5ce ov] ! editions ( t "w h]et(ore 9 use4 ,! ,que/ions & ,key1 likewise suppli$ by ,mr4 ,grim%aw to accompany ?is edition1 af=d a facility = communicat+ in/ruction1 :i* w be duly appreciat$ by e judici\s tea*]4 ,i am1 ,sir1 ,y\rs truly1 ,,?os4 ,t4 ,,smiley4 ,philadelphia1 ,sept4 #h1 #ahbf4 99 99 99 99 99 ,! ,editor ( ! ,unit$ ,/ates ,gazette1 9 speak+ ( ?is "w1 says--,goldsmi?'s ,greece1 )\t a revision1 is n calculat$ = s*ools2 x ab\nds 9 errors1 9 indelicate description1 improp] phrases1 & is1 inde$1 a pro( h[ v badly a good au?or c write1 if inde$ !re is n mu* room to d\bt ,goldsmi? ev] compos$ ! hi/ories to :i* 8 "n is atta*$4 ,mr4 ,grim%aw has adopt$ ! easy descriptive /yle ( t writ]1 reta9$ 8 facts1 connect$ 8 dates1 & entirely & h&somely adapt$ 8 "w to ! s*ool desk4 ,! book ( que/ions & ! accompany+ key1 are valuable additions to ! "w1 & w be f\nd mo/ s]viceable to tea*] & pupil4 ,f a k ( ! book1 & "s acqua9tance ) ! wants ( ^? = :om x 0 especially prep>$1 we unhesitat+ly recomm5d ,grim%aw's ,greece z "o ( ! be/ 79 our op9ion1 ! v be/ (7 works ( ! k9d t has be5 (f]$ to ! public4 ,,! ,,unit$ ,,/ates ,,speak]1 compil$ by ,t4 ,t4 ,smiley--pref]r$ g5]ally to ! ,columbian ,orator & ,scott's ,lessons1 & works ( t k9d1 by tea*]s :o h exam9$ x4 ,,goldsmi?',s ,,hi/ory ,,( ,,greece1 improv$ by ,grim%aw1 ) a ,vocabul>y ( ! ,prop] ,names conta9$ 9 ! "w1 & ! ,prosodial ,acc5ts1 9 con=mity ) ! ,pronunciation ( ,lempri]e--) ,que/ions & a ,key1 z above4 ,,grim%aw',s ,,etymological ,,diction>y ,,& ,,expositor ,,( ,,! ,,engli% ,,language4 99 99 99 99 99 ,transcrib]'s note3 ,spell+ v>iations :]e !re is no obvi\sly pref]r$ *oice h be5 pres]v$1 except z not$ bel[4 ,irregul>ities include3 bason & bas92 d]ivatives ( enquire & inquire2 le>n$ & le>nt2 sid]eal & sid]ial2 sun-rise & sunrise2 sun-set & sunset4 ,! orig9al use ( commas 0 pres]v$1 except :]e explicitly not$ bel[4 ,! orig9al spell+ ( p\rtray 0 pres]v$4 ,bo? ,roman & ,arabic num]als are us$ to numb] ! plates2 ! text 0 left z is4 ,pres]v$ ! non-/&>d ord] 9 ! index1 :]e ,u comes aft] ,v4 ,remov$ extra comma aft] :i* on page v3 ab\t :i* ! p>ts4 ,*ang$ ,sid]al to ,sid]ial on page vi3 ,sol>1 ,sid]ial1 & ,equal4 ,add$ comma aft] ,mrs4 ,b4 on page #i3 y\r assi/ance1 my ,de> ,mrs4 ,b41 9 a *>ge4 ,*ang$ errrone\s to errone\s on page #aj3 an errone\s conception4 ,add$ comma aft] ,mrs4 ,b4 twice on page #bc3 ,yet surely1 ,mrs4 ,b41 !re2 & ,b1 ,mrs4 ,b41 if attraction4 ,add$ commas be=e & aft] ,mrs4 ,b4 on page #be3 ,pray1 ,mrs4 ,b41 d4 ,*ang$ pullies to pulleys on page #fd3 a sy/em ( pulleys4 ,*ang$ plate #f4 fig4 #e to plate #e4 fig4 #e on page #fe 9 ! body ( ! text & 9 ! associat$ "q1 to designate ! correct figure4 ,*ang$ twelves to twelve on page #fe3 twelve times less4 ,*ang$ /ream to /eam on page #ff3 expansive =ce ( /eam4 ,*ang$ ,pray ,mrs4 ,b1 to ,pray1 ,mrs4 ,b41 on page #fh4 ,*ang$ nonela/ic to non-ela/ic on page #gj3 non-ela/ic l wat]4 ,remov$ extra comma aft] "o on page #gc3 "o w\ld ultimately h prevail$4 ,*ang$ eliptical to elliptical on page #gc3 elliptical or oval orbit4 ,*ang$ eclipse to ellipsis on page #gc3 motion 9 an ellipsis4 ,*ang$ elipsis to ellipsis on page #ge3 b an ellipsis4 ,*ang$ fig4 #d plate #c 9 ! "q on page #ge to fig4 #d4 plate #f to designate ! correct figure4 ,*ang$ day-light to daylight on page #gg3 see !m by daylight4 ,*ang$ ! second "q numb]$ #dj to #da f page #gi4 ,*ang$ eliptical to elliptical on page #hc3 !y 7 elliptical4 ,capitalis$ ,m]cury on page #hc3 made ^u ,m]cury4 ,add$ "q m>k on page #hd aft] ^? beautiful l9es ( ,milton4 ,remov$ repeat$ ^w1 x1 on page #hh3 provid$ x 7 /eady4 ,*ang$ a]i=m to a]i=m on page #acf 79 v]sions support+ full ,lat9-#a "* set74 ,*ang$ atmosph]ical to atmosph]ic on page #aci3 ! atmosph]ic air4 ,*ang$ r>ifies to r>efies on page #adj3 heat r>efies air4 ,*ang$ to day to to-day on page #aeg3 our lesson to-day4 ,*ang$ re-appe>ance to reappe>ance on page #aei3 reappe>ance ( ! sun4 ,*ang$ "q #bj to #bi on page #agd to ma9ta9 prop] sequ5ce4 ,*ang$ proportionably to proportionally on page #aih3 proportionally di/9ct4 ,ins]t$ comma aft] ,circle on page #bjf 9 ! gloss>y entry = ,circle1 ,less]4 ,ins]t$ p]iod on page #bjg at ! end ( ! gloss>y entry = ,cyl9d]4 ,*ang$ musisical to musical on page #bjh 9 ! gloss>y entry = ,h>mony4 ,*ang$ p]p5didicul> to p]p5dicul> on page #baa3 p]p5dicul> to ea* o!r4 ,*ang$ oppoite to opposite on page #bab3 ! opposite direction4 ,capitalis$ ,aries on page #bae3 ! fir/ degree ( ,aries4 ,*ange jr4 to ,jr4 9 ! adv]tisem5t = ,a ,pleas+ ,companion 4443 ,by ,jesse ,torrey1 ,jr4