,,fir/ ,,lessons ,,9 ,natural ,philosophy ,,= ,,beg9n]s4 ,,by ,,joseph ,c4 ,,m>t9dale1 ,m4,d41 ,,late ,,pr9cipal ,,( ,,madison ,,gramm> ,,s*ool1 ,,philadelphia2 ,,au?or ,,( ,a ,,hi/ory ,,( ,,! ,,unit$ ,,/ates ,,= ,,s*ools1 ,,etc4 ,illu/ration3 ,paddle:eel /eamboat4 ,,philadelphia3 ,,eldr$ge ,,bro!r1 ,no4 #ag ,nor? ,sev5? ,/reet4 #ahha4 ,ent]$1 accord+ to ,act ( ,congress1 9 ! ye> #ahgb1 by ,,eldr$ge ,,bro!r1 9 ! ,(fice ( ! ,libr>ian ( ,congress at ,wa%+ton4 ,j4 ,,fagan ,a ,,son1 ,,electrotyp]s1 ,,philad',a4 ,illu/ration3 ,,key/one ,,press ,,( ,w,m4 ,j4 ,,dornan ,preface4 ,illu/ration3 ,decoration ,9 prep>+ ?is little "w1 our desire has be5 to af=d bo? pleasure & pr(it to ^? :o may read or /udy its pages4 ,! mo/ int]e/+1 z well z ! mo/ useful ?+s to u1 are ^? ) :i* we meet 9 e-day life2 b we mu/ h "s k ( ^! ?+s1 ere we c contemplate !m ) mu* pleasure1 or use !m to our greate/ pr(it4 ,simple tru?s 9 natural sci5ce may be le>n$ at an e>ly age2 = x requires no m ?an ! ord9>y intellig5ce possess$ by boys & girls to und]/& !m4 ,su* facts are n only valuable 9 !mselves1 b !y are also useful 9 discipl9+ ! m9d by tea*+ x to obs]ve ! _m *anges con/antly go+ on ar\nd u1 & to reason & reflect 9 reg>d to ! same4 ,habits ( obs]vation & reflection ?us =m$ are likely to g ) u ?r\gh life2 & !y may prove a bless+ 9 a ?\s& ways2 = !y w n only add to our com=t & our enjoym5t1 b !y w also produce _m a pleas+ ?\ght4 ,we h endeavor$ to make a book t c be easily und]/ood2 b few sci5tific t]ms w be f\nd 9 x1 = its language is ! language 9 famili> use2 h5ce1 x may s]ve to int]e/ ! fireside circle1 & x may be ref]r$ to by intellig5t boys & girls = answ]s to ! _m p]plex+ que/ions :i* are s (t5 pres5t$ to _! inquir+ m9ds4 ,_m pupils h n ! *ance to att5d ev5 an ,academy or a ,high ,s*ool4 ,x is to su* t ?is book is especially adapt$1 = x is believ$ to conta9 z mu* matt] z c be taught ) satisfaction & pr(it 9 our public or our private s*ools2 b to o!r pupils1 x w prove a valuable introduction to l>g] & m compreh5sive works4 ,:5ev] a draw+ w\ld illu/rate a fact1 & make its application pla9]1 x has be5 made2 b by f> ! be/ illu/rations ( hundr$s ( facts1 expla9$ 9 ! text1 w be f\nd 9 ! _w ar\nd u1 & ! att5tion ( bo? pupil & tea*] %\ld always be direct$ to ?is reliable & nev]-end+ s\rce4 ,9 pres5t+ ^! ,famili> ,lessons 9 ,natural ,philosophy to ! y\? ( our c\ntry1 x is ) ! e>ne/ hope t x may make !m bett] acqua9t$ ) ! natural objects surr\nd+ u2 t x may lead !m to obs]ve ! ord]1 ! h>mony1 & ! beauty 9 nature ev]y:]e2 & t x may help to turn _! ?\ghts m & m to ,him1 :o is ! ,creator & ,rul] ( all ?+s4 ,j4 ,c4 ,m4 ,illu/ration3 ,decoration ,illu/ration3 ,,cont5ts ,,page ,,*apt] ,i4--,a/ronomy4 #i ,! ,e>? & o!r ,planets #i ,! ,moon #ad ,eclipses #ah ,,*apt] ,,ii4--,light4 #bb ,color #bb ,refraction ( ,light #cb ,reflection ( ,light #cd ,! ,eye #ch ,,*apt] ,,iii4--,heat4 #db ,s\rces ( ,heat #db ,expansion by ,heat #df ,conduction ( ,heat #ed ,convection ( ,heat #ei ,liquefaction #fa ,lat5t ,heat #fc ,ebullition #fe ,vaporization #ff ,evaporation #fi ,radiation #ga ,reflection #gc ,absorption #gd ,,*apt] ,,iv4--,! ,air4 #gg ,w9ds #if ,,*apt] ,v4--,wat]4 #ii ,spr+s & ,/reams #ajd ,fogs & ,cl\ds #ajf ,dew #aji ,fro/ #aab ,ra91 ,sn[1 & ,hail #aac ,ice #aaf ,,*apt] ,,vi4--,s\nd4 #aah ,conduction ( ,s\nd #abb ,trumpets & ,speak+-tubes #abe ,velocity ( ,s\nd #abg ,reflection ( ,s\nd #abh ,,*apt] ,,vii4--,matt]4 #aca ,,*apt] ,,viii4--,attraction4 #acg ,cohesion & ,adhesion #acg ,capill>y ,attraction #adj ,gravitation #ada ,c5tre ( ,gravity #ade ,specific ,gravity #aej ,,*apt] ,,ix4--,motion4 #aed ,,*apt] ,x4--,me*anical ,p[]s4 #afd ,lev] #afd ,:eel & ,axle #agd ,pulley #agf ,incl9$ ,plane #agg ,w$ge #ahj ,screw #aha ,,*apt] ,,xi4--,electricity4 #ahc ,magnetism #ahg ,electro-,magnetism #ahi ,,fir/ ,,lessons ,,9 ,natural ,philosophy4 ,,*apt] ,i4 ,a/ronomy4 ,! ,e>? & ,o!r ,planets4 ,illu/ration3 ,fig4 #a4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:at is ! %ape ( ! ,e>? on :i* we live8 ,x is r\nd l a ball4 ,:at o!r names are giv5 to ! ,e>?8 ,x is call$ ! ,_w or ,globe4 ,:at else is x sometimes call$8 ,x is call$ a ,planet4 ,are !re any o!r planets8 ,yes2 "s ( ! />s are call$ planets4 ,is our e>? or _w a />8 ,x is a />4 ,:y d ! o!r />s seem to u diff]5t f ! e>?8 ,because !y are s f> away f u4 ,:at gives light to ! planets8 ,! ,sun gives light to ! planets4 ,( :at is ! sun ! c5tre8 ,! sun is ! c5tre ( ! sol> sy/em4 ,d ! planets rema9 9 "o place8 ,! planets d n rema9 9 "o place1 b are always mov+4 ,h[ d ! planets move8 ,!y move ar\nd ! sun4 ,are "s planets ne>] ! sun ?an o!rs8 ,yes2 "s planets are mu* ne>] ! sun ?an o!rs4 ,:i* planet is ne>e/ ! sun8 ,! planet call$ ,m]cury4 ,:i* is next to ,m]cury8 ,! planet call$ ,v5us4 ,& :i* is ?ird 9 di/ance f ! sun8 ,our own planet1 ! ,e>?4 ,are !re any planets /ill f>!r f ! sun8 ,yes2 ,m>s1 ,jupit]1 ,saturn1 ,uranus1 & ,neptune1 & _m small] planets4 ,h[ does ea* planet move8 ,x moves 9 its own track or orbit ar\nd ! sun1 z is repres5t$ 9 ,fig4 #b4 ,illu/ration3 ,fig4 #b4 ,does ! e>? always move 9 ! same orbit ar\nd ! sun8 ,yes2 ! e>? moves 9 ! same orbit ar\nd ! sun1 ye> aft] ye>4 ,h[ long does x take ! e>? to move ar\nd ! sun8 #cfe days1 #e h\rs & #di m9utes1 or "o ye>4 ,:at makes a ye> to u8 ,a ye> to u is ! "t requir$ by ! e>? to move ar\nd ! sun4 ,if ! e>? is 9 a c]ta9 place at noon1 on ,new ,ye>'s day1 :5 w x be 9 t place aga98 #e h\rs & #di m9utes aft] noon on ,new ,ye>'s day ( ! next ye>4 ,:at1 !n1 does ! e>? d e ye>8 ,! e>? moves ar\nd ! sun & comes back to ! place :5ce x />t$1 once e ye>4 ,has ! e>? any o!r motion ?an ! "o ar\nd ! sun8 ,x has2 x turns ov] & ov]4 ,does ! e>? /ay 9 "o place z x turns ov] & ov]8 ,x does n2 x moves on 9 its track ar\nd ! sun4 ,h[ _m times does x turn ov] :ile go+ ar\nd ! sun8 ,?ree hundr$ & sixty-five times4 ,h[ _m times1 !n1 does x turn ov] 9 "o ye>8 ,! e>? turns ov] ?ree hundr$ & sixty-five times 9 a ye>4 ,:at is ! "t :i* x takes to turn ov] once call$8 ,x is call$ a day4 ,h[ _m days 9 a ye>8 ,!re are ?ree hundr$ & sixty-five days 9 a ye>4 ,:at two motions1 !n1 has ! e>?8 ,x turns ov] & ov]1 & at ! same "t x moves ar\nd ! sun4 ,:at *ange is produc$ on ! e>? by its mov+ ar\nd ! sun8 ,! *ange ( ,seasons4 ,w y "n ! seasons8 ,w9t]1 ,spr+1 ,summ]1 & ,autumn4 ,d !y foll[ ea* o!r 9 regul> ord]8 ,!y d2 ,spr+ foll[s ,w9t]1 ,summ] foll[s ,spr+1 ,autumn foll[s ,summ]1 ,w9t] foll[s ,autumn1 & ,spr+ foll[s ,w9t] aga94 ,h[ (t5 h we ^! seasons8 ,z (t5 z ! e>? moves ar\nd ! sun1 :i* is once a ye>4 ,:at *ange is produc$ on ! e>? by its turn+ ov]8 ,! *ange ( day & night4 ,:]e is x day8 ,x is day on t "p ( ! e>? :i* is turn$ t[>ds ! sun4 ,:]e is x night8 ,x is night on t "p ( ! e>? :i* is turn$ away f ! sun4 ,h[ (t5 d we h ! *ange f day to night8 ,z (t5 z ! e>? turns ov]1 :i* is once 9 tw5ty-f\r h\rs4 ,:at is a day8 ,a day is ! "t f sunrise till sunrise aga91 f sunset till sunset aga91 f noon till noon aga91 or f midnight till midnight aga94 ,:at does a day include8 ,x includes ! night-"t z well z ! day-"t1 ( ! tw5ty-f\r h\rs4 ,:5 x is day-"t on "o "p ( ! e>?1 :at is x on ! opposite "p8 ,x is night-"t on ! opposite "p4 ,:5 x is morn+ to u1 :at is x to p liv+ on ! opposite side ( ! e>?8 ,:5 x is morn+ to u1 x is ev5+ to !m2 :5 x is day-"t to u1 x is night-"t to !m2 & :5 x is noon to u1 x is midnight to !m4 ,on h[ mu* ( ! e>? is x always day8 ,x is day on "o-half ( ! e>?1 :ile on ! o!r half x is night4 ,! sun seems to move ar\nd ! e>?2 does x really d s8 ,no2 x does n move ar\nd ! e>?4 ,does ! e>? move8 ,yes2 x turns ov] once e day4 ,:y does x n seem to u to be mov+8 ,because we move along ) x4 ,if we are on a railroad c>1 ! trees & h\ses along ! road appe> to move1 & ! c> to /& /ill2 b ! c> really moves1 :ile ! trees & h\ses /& /ill4 ,9 :at direction does ! e>? turn on its axis8 ,! e>? turns f we/ to ea/4 ,:]e d ! sun1 moon1 & />s rise8 ,! sun1 moon1 & />s rise 9 ! ea/4 ,! tea*] may1 by means ( a ball or small globe1 readily make ^! ?+s s pla9 t !y c be und]/ood ev5 by small *ildr54 ,:5 is x sunrise to u8 ,:5 ! "p ( ! e>? on :i* we are1 fir/ comes into ! sun's rays4 ,:5 is x sunset to u8 ,:5 ! "p ( ! e>? on :i* we are1 moves out ( ! sun's rays4 ,! ,moon4 ,we h be5 told t ! e>? moves ar\nd ! sun2 does any planet move ar\nd ! e>?8 ,yes2 "o planet moves ar\nd ! e>?4 ,:at is t planet call$8 ,x is call$ ! ,moon4 ,illu/ration3 ,fig4 #c4 ,h[ (t5 does ! moon move ar\nd ! e>?8 ,once 9 #bg d4 #g h4 #dc m94 ,h[ long is ! "t f new moon to new moon aga98 ,x is #bi d4 #ab h4 #dd m94 ,h[ (t5 d we h new moon8 ,once e #bi d4 #ab h4 #dd m94 ,:at is ! p]iod f "o new moon to ano!r call$8 ,x is call$ a ,lun> mon?4 ,are ! lun> mon?s all ( ! same l5g?8 ,yes2 !y are all ( ! same l5g?4 ,is !re any o!r k9d ( mon?8 ,yes2 ! ,cal5d> mon?1 z x /&s 9 almanacs4 ,h[ _m cal5d> mon?s 9 a ye>8 ,!re are twelve cal5d> mon?s 9 a ye>4 ,are ! cal5d> mon?s all ( ! same l5g?8 ,no2 "s are ?irty-"o days long1 "s ?irty days long1 & "o only tw5ty-eight days long4 ,:5 c we see ! moon & />s be/8 ,we c see !m be/ :5 x is night4 ,f :at d ! moon & ! o!r planets get _! light8 ,!y get _! light f ! sun4 ,:at d !y d ) ?is light8 ,!y reflect x4 ,h[ d we see !m8 ,we see !m by ! light :i* !y reflect4 ,:y _c we see ! moon & />s 9 ! day-"t8 ,because ! bright light ( ! sun hides _! light4 ,are !re />s 9 e direction ar\nd ! e>?8 ,!re are />s 9 e direction ar\nd ! e>?4 ,h[ d we "k ?is8 ,because />s may be se5 f e "p ( ! e>?1 :5 x is night4 ,/>s are 9 e direction ar\nd ! e>?1 j z we may imag9e ! apples to be 9 e direction ar\nd a boy :o has climb$ into a tree full ( t fruit4 ,:at planet moves ar\nd ! e>?8 ,! moon moves ar\nd ! e>?4 ,^u :at "p ( ! moon does ! sun %9e8 ,x %9es ^u ! "p t[>ds ! sun4 ,:at does ! moon d ) ! light :i* x receives f ! sun8 ,! moon reflects ! light receiv$ f ! sun4 ,:at is ?is reflect$ light call$8 ,x is call$ moonlight :5 reflect$ f ! moon4 ,is t "p ( ! moon on :i* ! sun %9es always t[>ds ! e>?8 ,x is n always t[>ds ! e>?4 ,:5 all ( ! moon on :i* ! sun %9es is t[>ds ! e>?1 h[ does ! moon appe>8 ,! moon appe>s to be r\nd1 & ! :ole ( x seems to %9e4 ,:at is ! moon !n call$8 ,x is call$ ! ,full ,moon4 ,:5 no "p ( ! moon on :i* ! sun %9es is t[>ds ! e>?1 h[ does ! moon appe>8 ,we d n see ! moon at all1 & we say !re is no moon4 ,:5 a small "p ( ! moon on :i* ! sun %9es is fir/ turn$ t[>ds ! e>?1 :at is x call$8 ,x is call$ ! ,new ,moon4 ,does ! light$ "p ( ! moon gr[8 ,x seems to gr[ l>g] & l>g]1 until ! :ole ( ! moon is light$4 ,:at is x !n call$8 ,x is !n call$ ! ,full ,moon4 ,:at !n takes place8 ,x seems to gr[ small] & small]1 until ! :ole ( ! light$ "p is gone4 ,j be=e ! la/ "p is gone1 :at is x call$8 ,x is call$ ! ,old ,moon4 ,h[ long is x f "o full moon to ano!r full moon8 ,x is a lun> mon?4 ,h[ _m full moons are !re 9 a ye>8 ,!re are ?irte5 full moons 9 a ye>4 ,is ! sun mu* l>g] ?an ! moon8 ,! sun is _m ?\s& times l>g] ?an ! moon4 ,:y does ! moon appe> ne>ly z l>ge z ! sun8 ,because x is s mu* ne>] to u4 ,h[ f> is ! moon f ! e>?8 ,! moon is ne>ly #bdj1jjj miles f ! e>?4 ,h[ f> is ! sun f ! e>?8 ,! sun is ne>ly #ib1jjj1jjj miles f ! e>?4 ,h[ long does x take ! light ( ! sun to rea* ! e>?8 ,x takes ab\t eight m9utes2 !re=e1 ! light ( ! sun mu/ travel ab\t twelve millions ( miles 9 a m9ute1 or two hundr$ ?\s& miles 9 a second ( "t4 ,at ?is rate1 ! light w\ld come f ! moon to ! e>? 9 a little m ?an "o second ( "t4 ,x w\ld take no long] = x to come ?an x does = ! pulse to beat once1 or ! clock to make "o tick4 ,eclipses4 ,h[ d we "k t ! e>? is r\nd1 l a ball8 ,we "k t ! e>? is r\nd l a ball1 because its %ad[ is simil> to ! %ad[ ( a ball4 ,h[ else d we "k t ! e>? is r\nd8 ,we also "k t ! e>? is r\nd1 because we c circumnavigate or sail ar\nd x4 ,:]e c we see ! %ad[ ( ! e>?8 ,we c see ! %ad[ on ! moon1 :5 ! moon is eclips$4 ,:at is ! %ad[ on ! moon l8 ,x is r\nd1 l ! %ad[ ( a ball4 ,:5 ! ,e>? comes betwe5 ! sun & ! moon1 :]e does ! %ad[ ( ! e>? fall8 ,! %ad[ ( ! e>? falls on ! moon1 z is repres5t$ 9 ,fig4 #d4 ,illu/ration3 ,fig4 #d4 ,:at is ?is %ad[ on ! moon call$8 ,x is call$ an ,eclipse ( ! moon4 ,h[ d we "k t ! moon is r\nd8 ,we "k t ! moon is r\nd1 because its %ad[ is simil> to ! %ad[ ( ! e>?4 ,:5 is ! moon eclips$8 ,:5 x comes into ! e>?'s %ad[4 ,:5 ! moon comes fully into ! e>?'s %ad[1 :at is x call$8 ,x is call$ a total eclipse ( ! moon4 ,:5 x comes p>tly into ! e>?s %ad[1 :at is x call$8 ,x is call$ a p>tial eclipse ( ! moon4 ,:5 ! moon comes betwe5 ! sun & ! e>?1 :]e does ! %ad[ ( ! moon fall8 ,! %ad[ ( ! moon falls on ! e>?1 z is repres5t$ 9 ,fig4 #e4 ,illu/ration3 ,fig4 #e4 ,:at does ?is produce8 ,x produces an eclipse ( ! sun4 ,:5 ! moon is betwe5 ! sun & ! e>?1 c we see ! sun8 ,no2 we _c see ! sun1 because ! moon prev5ts ! rays ( ! sun f com+ to u4 ,:5 ! moon prev5ts ! sun's rays f fall+ on u1 :at is x call$8 ,x is call$ an eclipse ( ! sun4 ,:5 ! moon prev5ts all ! sun's rays f fall+ on u1 :at is x call$8 ,x is call$ a total eclipse ( ! sun4 ,:5 ! moon prev5ts only a "p ( ! sun's rays f fall+ on u1 :at is x call$8 ,x is call$ a p>tial eclipse ( ! sun4 ,:5 w ! sun be eclips$8 ,:5ev] ! moon comes betwe5 ! sun & ! e>?4 ,:5 w ! moon be eclips$8 ,:5ev] ! e>? comes betwe5 ! sun & ! moon4 ,:o made ! sun1 ! moon1 & ! />s8 ,god1 ! creator ( all ?+s1 made ! sun1 ! moon1 & ! />s4 ,he plac$ !m 9 ! heav5s1 :]e !y rema9 9 ob$i5ce to ,8 w4 ,he made ! bright rays f ! sun to light up ! day1 & give beauty to ! _w2 b ! feebl] rays ( ! moon & ! />s are se5 be/ at night1 :5 ! sun is hid4 ,illu/ration3 ,paddle:eel /eamboat4 ,illu/ration3 ,decoration4 ,,*apt] ,,ii4 ,light4 ,color4 ,illu/ration3 ,illu/rat$ ,capital ,i ,9 :at way is ! sun useful to u8 ,x gives heat1 :i* makes u w>m1 & x gives light1 s t we c see4 ,is x useful 9 any o!r way8 ,x gives light & w>m? to all animals z well z to all plants4 ,:at make ! fl[]s & leaves s beautiful8 ,! light & heat f ! sun make !m beautiful4 ,:at d ! light & heat f ! sun rip58 ,!y rip5 ! apples1 *]ries1 & o!r fruits2 also1 ! :eat1 corn1 & o!r gra9s1 & make !m fit = food4 ,:5 x is night-"t or d>k1 c we di/+ui% objects8 ,no2 because all ?+s are !n )\t color1 & !y _c be se54 ,z x gr[s light 9 ! morn+1 :at takes place8 ,at fir/1 we see ! objects ar\nd u fa9tly2 b z x gr[s light]1 we see !m m di/9ctly4 ,d !y all %[ ! same color 9 ! light8 ,!y d n2 !y %[ diff]5t colors4 ,:at enables u to see ! color ( diff]5t ?+s8 ,light enables u to see ! color ( ev]y?+4 ,:at k9ds ( light h we8 ,we h ! light ( ! sun1 moon1 & />s2 also1 ! light f ! burn+ ( any sub/ance4 ,does ! light %[ _m colors8 ,x does %[ _m colors or %ades ( color4 ,h[ may "s colors be made8 ,!y may be made by mix+ o!r colors toge!r4 ,h[ c we make a purple color8 ,by mix+ a r$ & a blue color toge!r4 ,h[ c a gre5 color be made8 ,by mix+ a blue & a yell[ color toge!r4 ,h[ c an orange color be made8 ,by mix+ a r$ & a yell[ color toge!r4 ,h[ does ! light come f ! sun8 ,x comes 9 rays or /raight l9es4 ,:at may be done ) a ray ( light8 ,x may be sep>at$ into diff]5t colors4 ,into h[ _m colors may a ray ( light be sep>at$8 ,into sev5 colors1 l ! colors ( ! ra9b[4 ,:at names are giv5 to ^! colors8 ,r$1 orange1 yell[1 gre51 blue1 indigo1 violet4 ,h[ may ^! colors be sep>at$8 ,by a prism1 or ?ree-sid$ piece ( glass4 ,h[ may ?is be done8 ,if a sunbeam1 %9+ ?r\gh a hole 9 ! w9d[-%utt] ( a d>k room1 %\ld fall ^u a prism1 x w be brok5 up z x passes ?r\gh ! prism1 & be %[n on ! opposite wall1 9 ! sev5 ra9b[ colors4 ,illu/ration3 ,fig4 #f4 ,9 ,fig4 #f1 ,d is a sunbeam pass+ ?r\gh a %utt]4 ,:5 x passes ?r\gh ! prism1 at ,e1 x is sep>at$ into ! sev5 ra9b[ colors1 z is %[n on ! opposite wall4 ,9 :at ord] w ^! colors appe>8 ,!y w always appe> "o above ! o!r1 9 ! ord] nam$4 ,h[ may ?is ord] be rememb]$8 ,by ! ^w ,roy-g-biv1 made f _! initial lett]s1 beg9n+ at ! bottom4 ,f :at are ! colors ( ! ra9b[ made8 ,f ! rays ( light com+ f ! sun4 ,:5 is a ra9b[ se58 ,a ra9b[ is se5 :5 ! sun %9es ?r\gh ! drops ( wat] z !y fall ?r\gh ! air4 ,h[ d ! drops ( wat] help to make a ra9b[8 ,! drops ( wat] act l little prisms1 & sep>ate ! rays ( light pass+ ?r\gh !m into ! colors ( ! ra9b[4 ,:at two ?+s1 !n1 are ne$$ to make a ra9b[8 ,a %[] ( wat]1 & a bright sun%9e4 ,9 :at "p ( ! sky does ! ra9b[ appe>8 ,9 ! "p opposite to t 9 :i* ! sun is1 at ! "t ( ! %[]4 ,h[ does ! ra9b[ appe>8 ,x appe>s l a great ar*1 spann+ ! sky1 & its spl5did bright colors are v beautiful4 ,:at may we rememb] 9 ref]5ce to ! ra9b[8 ,we may rememb] t ,god set 8 8b[0 9 ! cl\d1 z a tok5 t ! _w %\ld no m be de/roy$ by a flood ( wat]s4 ,:]e else may we see a v>iety ( colors8 ,9 ! soap-bubble4 ,:y are ^! colors con/antly *ang+8 ,because ! walls ( ! bubble are con/antly gr[+ ?9n]1 & diff]5t colors are1 !re=e1 reflect$ f !m4 ,:y d ! walls ( ! soap-bubble gr[ ?9n]8 ,because ! wat] runs to ! bottom ( ! bubble until its top becomes s ?9 z to bur/4 ,c we tell ! color ( any object by t\*+ x8 ,no2 we mu/ see x 9 ord] to tell its color4 ,h[ d we "k ?is8 ,if !re are two coats1 "o blue & ! o!r black1 we _c tell :i* is ! blue "o or :i* is ! black "o1 by feel+ !m4 ,:at is necess>y 9 ord] to see ! colors8 ,light is necess>y2 because all colors come f ! rays ( light4 ,c we see ! diff]5t colors 9 ! ray itself8 ,we _c2 because ,god has s bl5d$ !m toge!r t !y _c be se5 by u4 ,:5 mo/ ( ! rays ( light pass ?r\gh a sub/ance1 :at is said ( x8 ,! sub/ance is said to be transp>5t4 ,"n "s transp>5t sub/ances4 ,glass1 ice1 diamonds1 air1 & cle> wat]4 ,:5 only a few rays ( light pass ?r\gh a sub/ance1 :at is said ( x8 ,! sub/ance is said to be transluc5t4 ,"n "s transluc5t sub/ances4 ,fl9t1 is+lass1 scrap$-horn1 & *9a-w>e4 ,:5 no rays ( light pass ?r\gh a sub/ance1 :at is said ( x8 ,! sub/ance is said to be opaque4 ,"n "s opaque sub/ances4 ,wood1 iron1 coal1 & granite4 ,c we see ?r\gh a glass w9d[8 ,yes2 because ! glass is transp>5t1 & ! light passes ?r\gh x4 ,c we see ?r\gh a look+-glass8 ,no2 because ! back ( ! look+-glass is cov]$ ) quicksilv]1 :i* prev5ts ! rays ( light f pass+ ?r\gh x4 ,:at becomes ( ! light fall+ on ! look+-glass8 ,x is ?r[n back f ! glass4 ,:at is ?is call$8 ,x is call$ reflection4 ,:at objects are good reflectors ( light8 ,^? hav+ smoo? & poli%$ surfaces2 su* z t91 silv]1 gold1 & quicksilv]4 ,:at objects are poor reflectors ( light8 ,^? hav+ dull1 unev5 surfaces2 su* z iron1 wood1 clo?1 lea!r1 & calico4 ,( :at is e ray ( sunlight compos$8 ,x is compos$ ( ! sev5 colors ( ! ra9b[4 ,:at does a look+-glass d ) ^! colors8 ,a look+-glass ?r[s !m all back f its surface4 ,:at does a glass w9d[ d ) ^! colors8 ,a glass w9d[ p]mits all ^! colors to pass ?r\gh x4 ,:at d opaque sub/ances d ) ^! colors8 ,!y ?r[ back or reflect "s ( !m4 ,d !y all reflect ! same color8 ,no2 "s reflect "o color1 & "s ano!r color4 ,:at color does ! grass reflect8 ,x reflects ! gre5 color2 !re=e1 ! grass is gre54 ,:at does ! grass d ) ! o!r colors8 ,x absorbs or hides !m 9 itself4 ,h[ d we "k ! color ( any?+8 ,we "k x by ! color :i* x reflects4 ,:y is ! rose r$8 ,because x reflects ! r$ color1 & absorbs or hides ! o!r colors 9 itself4 ,:5 any?+ absorbs all ! colors ( a ray ( light1 :at color is x8 ,x is black4 ,:5 x reflects all ! colors ( light1 :at color is x8 ,x is :ite4 ,:y are ! lett]s on ?is page black8 ,because !y absorb all ! colors ( light1 & reflect none4 ,:y is ! pap] :ite8 ,because x reflects all ! colors ( light1 & absorbs none4 ,:y are all ?+s black 9 ! d>k8 ,because !re are no rays ( light fall+ on !m2 h5ce1 !re is no color = !m to reflect4 ,does an object reflect its color 9 e direction8 ,x does reflect its color 9 e direction4 ,h[ d we "k ?is8 ,because ?\s&s ( p]sons1 9 diff]5t directions f ! same object1 c see x at ! same "t4 ,h[ are ! rays ( color reflect$ f an object8 ,!y are reflect$ 9 /raight l9es4 ,:]e mu/ a p]son be s z to see an object8 ,he mu/ be 9 a position s t !re is no?+ to prev5t ! rays ( light pass+ 9 a /raight l9e f ! object to 8 eyes4 ,:at color does a r$ ribbon reflect8 ,x reflects a r$ color4 ,:y are "s r$ ribbons ( a bright] r$ ?an o!rs8 ,:5 !y reflect a great _m r$ rays1 !y are ( a bright r$ color2 b :5 !y reflect only a few r$ rays1 !y are ( a dull r$ color4 ,^u :at does ! brightness or dullness ( a color dep5d8 ,x dep5ds ^u ! numb] ( rays ( t color reflect$4 ,:at v>iety does ?is produce8 ,x produces a great v>iety 9 ! %ades & t9ts ( color4 ,:]e may _m ( ^! %ades & t9ts be se58 ,9 ! pretty fl[]s t gr[ 9 ! woods1 fields1 & g>d5s2 9 ! beautiful t9ts ( ! leaves 9 autumn2 & 9 ! plumage ( ! birds t visit u e spr+1 & *e] u ) _! songs4 ,:at may ^! ?+s tea* u8 ,!y may tea* u ! goodness ( ,god1 9 giv+ u a _w s full ( beauty2 & we %\ld feel ev] ?ankful to ,him = ! great pleasure t we h 9 see+ !m4 ,:y _c we see ! light ( a lamp or c&le di/9ctly1 9 ! day-"t8 ,because ! /rong rays f ! sun hide ! m feeble rays f ! lamp4 ,:y _c we see ! />s 9 ! day-"t8 ,because ! bright light f ! sun hides _! m feeble light4 ,:5 c we see ! gl[-worms or fire-flies be/8 ,at night1 :5 x is d>k2 because1 at o!r times1 ! light ( ! sun hides _! feeble light4 ,:]e may we see !m at night8 ,fly+ ab\t 9 all directions1 look+ l bits ( fire mov+ 9 ! air4 ,does a look+-glass reflect all ! colors ( light fall+ ^u x8 ,x does2 h5ce1 ! ray ( light is n *ang$4 ,:5 ! object is ( a blue color1 :y is blue only reflect$8 ,because x is ! only color fall+ ^u ! glass1 & !re is no o!r color to reflect4 ,is ! color ( any object *ang$ by fall+ ^u a look+-glass8 ,no2 ! color ( e object is reflect$ f a look+-glass )\t *ange4 ,d o!r objects g5]ally reflect ! colors fall+ ^u !m8 ,!y d n2 !y absorb or hide ! color ( all o!r objects1 & reflect only _! own color4 ,if e object 0 a good reflector ( color1 l a look+-glass1 :at w\ld result8 ,!n e object w\ld reflect ! color ( e o!r object ar\nd x1 & !re w\ld be an endless confusion ( colors4 ,:at objects reflect ! mo/ light8 ,^? ( a :ite or light color4 ,:at objects reflect ! lea/ light8 ,^? ( a d>k] color2 & ! ne>] ! color approa*es to black1 ! less light x reflects4 ,:y is x d>k] :5 ! sky is cov]$ by d>k-color$1 ?an by light-color$1 cl\ds8 ,because ! d>k-color$ cl\ds reflect less light1 ?an ! light-color$ cl\ds d4 ,:at advantage d we d]ive f ! gre5 color ( ! grass & ! leaves8 ,!y reflect a s(t1 pleasant light1 :i* does n dazzle or hurt our eyes4 ,h[ w\ld x be if ^? objects 7 :ite8 ,!y w\ld dazzle u by ! am\nt ( light reflect$4 ,if we wi% to make a room light1 ( :at color %\ld ! walls be8 ,!y %\ld be :ite2 & :5 pap]$1 x %\ld be ) light-color$ pap]4 ,:y does d>k-color$ pap] d>k5 a room8 ,because x absorbs "s ( ! rays ( light :i* come 9 at ! w9d[s2 h5ce1 !re is less light 9 ! room4 ,d>k-color$ c>pets1 or d>k furniture1 d>k5 ! room = ! same reason4 ,does ! light f a burn+ body diff] f sun-light8 ,yes2 x diff]s 9 int5sity1 9 color1 & 9 _m o!r ways4 ,:at effect does ! lamp-light h ^u ! color ( "s sub/ances8 ,x *anges _! color4 ,:]e may we f9d an example ( ?is8 ,9 try+ to mat* ! colors ( ?read or silk at night4 ,:y is ! color diff]5t by lamp-light f :at x is by daylight8 ,because ! yell[ color ( ! lamp's rays acts ^u ! color ( ! silk1 =m+ a ?ird color4 ,blue silk becomes gre5 by lamp-light1 & r$ silk becomes orange4 ,are all p]sons able to di/+ui% "o color f ano!r8 ,no2 "s are color-bl9d4 ,to su* p]sons all colors appe> to be alike4 ,:at curi\s in/ances ( color-bl9dness may be m5tion$8 ,dr4 ,mit*ell tells ( an (fic] :o b\ght a blue coat & a r$ wai/coat1 ?9k+ !m to be ( ! same color4 ,he also tells ( a tailor :o pat*$ a black wai/coat ) a piece ( crimson2 & ( ano!r1 :o put a r$ coll> on a blue coat4 ,dr4 ,dalton lo/ a piece ( r$ seal+-wax 9 ! grass1 & he c\ld n f9d x because x & ! grass seem$ ( ! same color to him4 ,refraction ( ,light4 ,h[ d ! rays ( light f ! sun come to u8 ,!y come to u 9 /raight l9es4 ,:5 ! rays ( light pass f "o sub/ance to ano!r m d5se1 :at takes place8 ,!y are b5t or turn$ f a /raight c\rse4 ,:at is said ( ^! b5t rays8 ,!y are said to be refract$4 ,:at is meant by refraction8 ,b5d+ a ray ( light1 z x passes f "o sub/ance to ano!r ( diff]5t d5sity2 z f air to wat]1 or f wat] to air4 ,:]e may we see an example ( refraction8 ,9 ! rays ( light f a rod :i* has "o end 9 ! wat]4 ,illu/ration3 ,fig4 #g4 ,:y does ! rod appe> to be b5t8 ,because light com+ f ! "p ( ! rod "u ! wat]1 is refract$ or b5t at ! surface ( ! wat]1 :ile ! light f ! "p above ! surface1 comes 9 /raight l9es to ! eye2 h5ce1 ! rod appe>s to be b5t at ! surface1 z is repres5t$ 9 ,fig4 #g4 ,h[ does a pole appe> :5 "o end is plac$ 9 ! wat]8 ,x appe>s to be b5t :]e x meets ! surface ( ! wat]4 ,h[ does ! "p ( ! rod "u wat] appe>8 ,! "p "u ! wat] appe>s to be rais$ up1 z may be se5 9 ,fig4 #g4 ,h[ does ! bottom ( a pond or /ream ( wat] appe>8 ,x appe>s to be rais$ up1 & ! wat] does n seem s deep z x really is4 ,:y is ?is ! case8 ,because ! light f ! bottom ( ! pond is refract$ or b5t at ! surface ( ! wat]2 h5ce1 ! bottom appe>s to be rais$ up4 ,h[ mu* does ! bottom ( a pond or /ream ( wat] seem to be rais$ up8 ,ab\t "o-?ird ( ! dep? ( ! wat]4 ,if ! wat] is really six feet deep1 h[ deep does x appe>8 ,x appe>s to be only f\r feet deep4 ,:at has frequ5tly happ5$ f n kn[+ ?is fact8 ,p h be5 dr[n$ f gett+ into wat] deep] ?an x appe>$ to be4 ,d ! fi% & o!r ?+s float+ 9 ! wat] appe> to be rais$ up8 ,yes2 l ! bottom ( ! /ream1 !y also appe> to be only two-?irds z f> f ! surface z !y really are4 ,if we wi% to spe> ! fi%1 :at mu/ we d8 ,we mu/ aim bel[ ! place :]e !y seem to be1 or we mu/ /rike p]p5dicul>ly at !m4 ,reflection ( ,light4 ,:5 a ball is ?r[n aga9/ a wall1 :at is ! pa? ?r\gh :i* x goes call$8 ,! l9e ( incid5ce4 ,:5 ! ball b\nds back1 :at is its pa? call$8 ,! l9e ( reflection4 ,:at is ! angle at :i* a ball /rikes ! wall call$8 ,! angle ( incid5ce4 ,:at is ! angle at :i* ! ball reb\nds call$8 ,! angle ( reflection4 ,:5 a ray ( light falls ^u a look+-glass1 :at is ! pa? ?r\gh :i* x goes call$8 ,! l9e ( incid5ce4 ,:5 ! ray is reflect$1 :at is its pa? call$8 ,! l9e ( reflection4 ,! angle ( incid5ce is ! angle betwe5 a p]p5dicul> & ! l9e ( incid5ce2 & ! angle ( reflection is ! angle betwe5 ! p]p5dicul> & ! l9e ( reflection4 ,! two angles are always equal to ea* o!r1 z is repres5t$ 9 ,fig4 #h4 ,illu/ration3 ,fig4 #h4 ,:5 a ray ( light /rikes a look+-glass obliquely or slant+ly1 :at is done ) x8 ,! ray is reflect$ z obliquely f ! glass z x /rikes or falls ^u x4 ,:y is ! reflection ( ! sun 9 a pond ( wat] se5 ne> ! edge at noon8 ,because ! angle ( reflection is equal to ! angle ( incid5ce2 & ! obs]v] mu/ be ne>ly ov] ! place :]e ! rays /rike1 s t1 :5 reflect$1 !y may meet 8 eye4 ,:]e is ! reflection se5 9 ! morn+ or 9 ! ev5+8 ,x is se5 ne>] ! middle ( ! pond2 because ! sun's rays !n fell m obliquely on ! pond1 & are reflect$ m obliquely to ! eye4 ,:5 an opaque object is plac$ betwe5 a c&le & a wall1 :y w !re be a %ad[8 ,because ! opaque object prev5ts ! rays ( light f fall+ on ! wall4 ,:y w ! %ad[ be l>g]1 ! ne>] ! object is to ! c&le8 ,because ! rays ( light div]ge1 9 e direction f ! c&le1 9 /raight l9es1 & ! ne>] ! object1 ! m rays w x int]cept1 z is repres5t$ 9 ,fig4 #i4 ,illu/ration3 ,fig4 #i4 ,9 ,fig4 #i1 let ,l repres5t ! flame ( a c&le4 ,:5 ! object is plac$ at ,a1 ! %ad[ on ! wall w ext5d f ,c to ,d2 b :5 ! object is mov$ ne>]1 z at ,b1 ! %ad[ w ext5d f ,e to ,f4 ,:y does an object seem to be small]1 ! f>!r x is f u8 ,because ! angle at :i* ! light f x /rikes ! eye1 is less :5 at a di/ance1 ?an :5 ne> to ! eye4 ,illu/ration3 ,fig4 #aj4 ,9 ,fig4 #aj1 ! diamet] ( ! ne> circle is f ,a to ,b2 b ! diamet] ( ! m di/ant circle1 al?\gh j z l>ge1 seems only to be f ,c to ,d4 ,:y does an object gr[ m dim ! f>!r x is f u8 ,because ! rays ( light f x spread out 9 e direction2 & few] rays ent] ! eye :5 x is at a di/ance ?an :5 x is ne> by4 ,:at is ! use ( ! telescope8 ,x is us$ to view di/ant objects4 ,:y c we see a di/ant object m di/9ctly ) a telescope1 ?an )\t "o8 ,because ! telescope enl>ges ! image ( ! object1 & x also collects m light f t object ?an is collect$ by ! unaid$ eye2 ?us1 mak+ ! image di/9ctly visible4 ,:at class ( objects d we view ) a telescope8 ,we view ! heav5ly bodies2 ! sun1 moon1 & />s4 ,:at is a spy-glass8 ,x is a glass mo/ly us$ to view di/ant objects on ! e>?4 ,is ! spy-glass l ! telescope8 ,! spy-glass is mu* l ! telescope1 only x is small]4 ,:5 look+ ?r\gh a spy-glass1 h[ d objects appe>8 ,!y seem to be br\ght ne>] to u1 & !y appe> l>g]4 ,by :om are spy-glasses mu* us$8 ,spy-glasses are mu* us$ by p]sons on bo>d ( vessels1 :ile at sea4 ,:at in/rum5ts h we = magnify+ small objects8 ,we h magnify+ glasses & microscopes4 ,:at are magnify+ glasses8 ,!y are s+le glasses or l5ses1 us$ = magnify+ small objects4 ,by :om are magnify+ glasses us$8 ,!y are us$ by jewell]s1 wat*mak]s1 engrav]s1 & o!rs :o exam9e small objects4 ,:at are microscopes8 ,!y are in/rum5ts us$ = exam9+ v small objects4 ,h[ does a drop ( ra9-wat] or v9eg> appe> "u ! microscope8 ,x appe>s to be full ( /range-look+ creatures1 :i* are always 9 motion4 ,h[ d ! smalle/ insects appe>8 ,!y appe> to be z p]fectly =m$ z ! l>g] ones :i* are se5 ) ! nak$ eye4 ,:at may be se5 ) a microscope8 ,?\s&s ( ?+s too small to be se5 by u unless !y are magnifi$4 ,:at k9d ( spectacles d ne>-sight$ p use8 ,ne>-sight$ p use glasses1 ?icke/ at ! edge & ?9ne/ at ! c5tre4 ,:at k9d ( spectacles d we use z we gr[ old8 ,z we gr[ old we use glasses1 ?9ne/ at ! edge & ?icke/ at ! c5tre4 ,( :at use are spectacles8 ,:5 ! vision is defective1 spectacles enable u to see objects m cle>ly4 ,h[ %\ld spectacles be made8 ,!y %\ld be s made z to r5d] objects di/9ct1 b nei!r to magnify nor dim9i% !m4 ,z p gr[ old1 h[ d _! eyes *ange8 ,_! eyes *ange s t !y see objects at a di/ance bett] ?an ^? :i* are ne>]1 h5ce1 9 read+ !y hold a book f>!r f ! eye4 ,! ,eye4 ,:at is t "p ( ! eye call$1 :i* is blue1 gray1 or br[n1 9 diff]5t p]sons8 ,x is call$ ! iris4 ,:at is ! pupil ( ! eye8 ,! pupil is ! black spot or hole 9 ! c5tre ( ! iris4 ,illu/ration3 ,fig4 #aa4 ,:at is ! use ( ! pupil8 ,! pupil is ! w9d[ ( ! eye1 & ! rays ( light :i* ent] ! eye mu/ pass ?r\gh x4 ,:at p[] has ! iris ov] ! pupil8 ,! iris has ! p[] ( mak+ ! pupil l>g] or small]1 accord+ to ! am\nt ( light :i* x receives4 ,h[ does a bright light affect ! iris8 ,x causes ! iris to contract1 s t ! pupil becomes small]4 ,h[ does a fa9t light affect ! iris8 ,x causes ! iris to dilate1 s t ! pupil becomes l>g]4 ,( :at advantage is ! iris to ! eye8 ,! iris acts l a s5t9el to protect ! eye f any sudd5 light4 ,h[ does a sudd5 light affect ! eye8 ,a sudd5 light causes pa9 to ! eye4 ,( :at %ape is ! pupil ( ! eye8 ,9 man1 ! pupil ( ! eye is circul>4 ,:at is ! size ( ! pupil ( ! eye8 ,! pupil v>ies f ! "o-tw5tie? to ! "o-?ird ( an in* 9 diamet]1 dep5d+ ^u ! brightness ( ! light ent]+ ! eye4 ,h[ else are our eyes protect$ f any sudd5 light8 ,by means ( our eyelids1 :i* may be clos$1 & ?us %ut out all ! light4 ,:5 we pass f a well-light$ room into ! op5 air1 at night1 :y does x seem d>k] at fir/ ?an x does aft]w>ds8 ,because ! pupil is contract$ at fir/2 b x soon dilates1 & all[s m rays ( light to pass into ! eye1 s t ! night seems less d>k4 ,:y does ! pupil become l>g] 9 ! twilight8 ,s t m rays ( light may ent] ! eye1 :]eby objects may be m di/9ctly se54 ,:y c an owl or a bat see at night8 ,because ! pupil ( ! eye 9 !m is q l>ge1 & admits mu* light4 ,:y d !y /ay 9 d>k places ?r\gh ! day8 ,because ! bright light ( day hurts _! eyes4 ,may ! image ( an object be reta9$ 9 ! eye aft] ! eyelids are clos$8 ,x may = a v %ort "t1 z any "o c prove by fir/ look+ at "s bright object1 & !n clos+ ! eyelids4 ,:y does a burn+ coal mov$ rapidly ar\nd1 seem l a circle ( fire8 ,because ! light f x is reta9$ a %ort "t by ! eye1 ?us seem+ to =m a complete circle4 ,:y _c we c\nt ! po/s 9 a f5ce1 :5 rid+ rapidly 9 a c>8 ,because ! light f ea* po/ falls 9 su* quick succession ^u ! eye1 t x _c di/+ui% "o po/ f ano!r4 ,c objects be se5 di/9ctly :5 plac$ ne> ! eye8 ,no2 :5 objects are )9 six in*es ( ! eye !y _c be se5 di/9ctly4 ,c objects be se5 :5 at a great di/ance f ! eye8 ,yes2 objects may be se5 ev5 :5 millions ( miles away f u2 ?us1 ! sun is se5 al?\gh n9ety-five millions ( miles f ! e>?1 & "s ( ! />s :i* we behold 9 ! heav5s1 are /ill f>!r away ?an ! sun4 ,( :at use is ! eye to u8 ,! eye gives u ideas ( ! size1 ! %ape1 ! color1 ! place1 ! di/ance1 & ! movem5ts ( ?+s ar\nd u1 s t we c use !m ! bett] to promote our com=t & our happ9ess4 ,:at may we rememb] ab\t ! light8 ,& ,god said1 8,let !re be light20 & !re 0 light4 ,?us ! day 0 sep>at$ f ! night1 & ! sun 0 made to s5d =? 8 silv]y rays ^u hill & valley1 field & =e/1 caus+ ! r>e/ buds & mo/ beautiful blossoms to come =? f ! lifeless e>?1 al?\gh no eye1 save ! ,all-,see+ ,"o1 0 !re to behold !m6 ,illu/ration3 ,locomotive4 ,illu/ration3 ,decoration4 ,,*apt] ,,iii4 ,heat4 ,s\rces ( ,heat4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:at is heat8 ,heat is t ag5t :i* causes ! feel+ ( w>m?4 ,c heat be se58 ,no2 heat _c be se51 x c only be felt4 ,:5 we t\* a sub/ance hott] ?an we are1 :at takes place8 ,a "p ( ! heat f t sub/ance comes to u & causes a feel+ ( w>m?4 ,:5 we t\* a sub/ance cold] ?an we are1 :at takes place8 ,a "p ( ! heat f u goes to t sub/ance1 & we exp]i5ce a feel+ ( cold4 ,does ! am\nt ( heat 9 any sub/ance v>y8 ,yes2 wat] may be heat$ until x is scald+ hot1 or ! heat may be tak5 f x until x is froz5 into ice4 ,:at causes a sub/ance to become cold8 ,tak+ away heat f a sub/ance causes x to become cold4 ,!n :at is cold8 ,cold is only ! abs5ce or want ( heat4 ,:5 we pass f a v hot room to "o mod]ately w>m1 h[ d we feel8 ,we exp]i5ce a feel+ ( cold4 ,:5 we pass f a v cold room to "o mod]ately w>m1 h[ d we feel8 ,we h a feel+ ( w>m?1 al?\gh ! room is no w>m] ?an 9 ! fir/ in/ance4 ,h[ else c we prove t we judge ( heat & cold by our feel+s8 ,if "o h& be held 9 q w>m wat]1 & ! o!r 9 q cold wat]1 = a few mom5ts1 & !n bo? h&s be plung$ into tepid wat]1 ! tepid wat] w feel cold to ! h& t 0 9 ! w>m wat]1 & w>m to ! h& t 0 9 ! cold wat]4 ,is !re any?+ )\t heat8 ,no2 ! colde/ sub/ance kn[n /ill conta9s "s heat4 ,h[ _m k9ds ( heat are !re8 ,!re are two k9ds ( heat4 ,:at are ! two k9ds ( heat8 ,heat accompani$ by light1 z ! heat f ! sun1 or a lamp2 & heat )\t light1 z ! heat f boil+ wat]4 ,f :at s\rce does heat mo/ly come8 ,heat mo/ly comes f ! sun1 :i* is also ! s\rce ( light4 ,:at is said ( ! heat & light f ! sun8 ,heat & light f ! sun come toge!r 9 ! sunbeam4 ,f :at o!r s\rce is heat obta9$8 ,heat is obta9$ f ! burn+ ( any sub/ance4 ,:at else does ! burn+ ( any sub/ance produce8 ,x (t5 produces light4 ,c ! light & heat f ! sun easily be sep>at$8 ,!y _c easily be sep>at$4 ,:at does a glass w9d[ d ) ! light & heat ( ! sunbeam8 ,x p]mits bo? ! light & ! heat to pass into ! room1 s t we c see ! "o & feel ! o!r4 ,are ! light & heat f a fire unit$1 z !y are 9 ! sunbeam8 ,!y are n2 b !y seem to be sep>at$ f ea* o!r4 ,:at does a glass w9d[ d ) ! light & heat f a fire8 ,x p]mits ! light to pass ?r\gh2 b x /ops ! heat4 ,h[ may ?is be prov$8 ,:5 a pane ( glass is held betwe5 ! face & a fire1 x w protect ! face f ! heat4 ,is !re any heat )\t light8 ,yes2 _m sub/ances conta9 heat1 b d n emit light4 ,does light *ange ! am\nt ( heat 9 a sub/ance8 ,no2 boil+ wat] is z hot 9 ! d>k z x is 9 ! light2 & ice is z cold 9 ! daytime z x is at night4 ,is !re any o!r s\rce ( heat8 ,yes2 heat is produc$ by rubb+ or /rik+ sub/ances toge!r4 ,:at w result f rubb+ two pieces ( wood toge!r8 ,!y may be rubb$ until !y take fire4 ,h[ d ,indians k9dle fires8 ,by rubb+ two pieces ( wood toge!r until !y take fire4 ,h[ is heat produc$ by ! brakes on railroad c>s8 ,x is produc$ by ! c>-:eels rubb+ aga9/ ! brakes4 ,:at may be se5 :5 a horse /rikes 8 %oes aga9/ a /one8 ,small sp>ks ( fire1 :i* conta9 heat1 may be se54 ,if a piece ( iron be hamm]$1 w its heat be increas$8 ,its heat w be increas$4 ,h[ c ?is be prov$8 ,a p]son c1 by hamm]+ a piece ( cold iron1 make x r$-hot4 ,c\ld we live )\t heat8 ,no2 our bodies mu/ be kept w>m1 & ?is c be done only by heat4 ,is ?is true ( o!r liv+ ?+s8 ,yes2 all ! animals & all ! plants w\ld die if heat 7 tak5 away4 ,h[ %\ld we feel 9 reg>d to ^! ?+s8 ,we %\ld feel ?ankful to an ,all-wise ,creator1 = hav+ provid$ u ) bo? heat & light f a nev]-fail+ s\rce--! sun4 ,expansion by ,heat4 ,h[ does heat g5]ally affect sub/ances8 ,heat exp&s !m or makes !m l>g]4 ,does heat exp& all metals8 ,yes2 all metals are exp&$ by heat4 ,:5 a rod ( iron is heat$1 is x long] or %ort] ?an :5 cold8 ,x is long] ?an :5 x is cold4 ,h[ d we "k ?is8 ,we "k x by measur+ ! rod :5 x is cold1 & aga9 :5 x is heat$4 ,w ! rod be l>g]1 z well z long]8 ,! rod w be l>g]4 ,h[ c we prove ?is8 ,! rod1 :5 r$-hot1 w n g ?r\gh z small a hole z :5 x is cold4 ,h[ d heat & cold affect mo/ sub/ances8 ,heat exp&s mo/ sub/ances1 & cold contracts !m4 ,d all metals exp& alike by heat8 ,no2 "s metals exp& mu* m ?an o!rs4 ,h[ does heat exp& sub/ances8 ,heat pu%es ! p>ts or atoms ( an object f>!r f ea* o!r1 & ?us its size is increas$4 ,:at does a blacksmi? d ) a tire be=e putt+ x on a :eel8 ,he heats ! tire r$-hot4 ,:y does he heat ! tire r$-hot8 ,s t x w be increas$ 9 size1 & w g on ! :eel m easily4 ,:at takes place z ! tire cools8 ,x becomes small]1 & ?us b9ds ! p>ts ( ! :eel tightly toge!r4 ,:5 a fire is made 9 a room1 :y does ! furniture (t5 make a snapp+ noise8 ,because heat exp&s ! wood1 & ! p>ticles make a snapp+ noise ^u sep>at+4 ,:y does a /ove make a crackl+ noise z x gr[s hot8 ,! p>ticles ( ! iron make ! noise 9 exp&+4 ,if a piece ( glass be held 9 ! h&1 w ! glass become w>m8 ,! glass w become z w>m z ! h&4 ,:at "p ( ! glass w be w>m$ fir/8 ,! "p t\*+ ! h& w be w>m$ fir/4 ,:at "p ( ! glass w be w>m$ la/8 ,! "p f>!/ f ! h& w be w>m$ la/4 ,:i* "p ( ! glass w be exp&$ fir/8 ,! "p t\*+ ! h&1 because x is fir/ w>m$4 ,:i* "p w be exp&$ la/8 ,! "p f>!/ f ! h&1 because x is ! la/ "p w>m$4 ,if any o!r w>m sub/ance t\* ! glass1 w ! glass be heat$ 9 ! same mann]8 ,! glass w be heat$ 9 ! same mann]4 ,:at (t5 results f ?is unequal heat+8 ,! glass is brok54 ,:y are glass plates or tumbl]s brok5 :5 plac$ 9 hot wat]8 ,!y are brok5 because ! "p next to ! hot wat] is exp&$ m ?an t f>!r away4 ,:y w a clo? dipp$ 9 hot wat] & wrapp$ ar\nd ! neck ( a bottle loos5 its /opp]8 ,because ! heat f ! clo? exp&s ! neck ( ! bottle be=e x does ! /opp]1 s t ! /opp] is loos5$4 ,:y d /ove-plates (t5 break8 ,because !y are fitt$ toge!r 9 ! /ove s t !y h n room to exp& )\t break+4 ,:at effect has cold ^u sub/ances8 ,cold causes !m to contract or gr[ small]4 ,?+s exp& unequally2 d !y also contract unequally8 ,!y d contract unequally1 & 9 ?is way may be brok54 ,:y are lamp *imneys (t5 brok5 :ile ! lamp is burn+8 ,because ! heat ( ! flame causes !m to exp& unequally4 ,9 :at o!r way are !y brok58 ,by a draught ( cold air1 or a drop ( cold wat]1 t\*+ !m1 ?us caus+ !m to contract unequally4 ,:y are !y sometimes brok5 :5 ! lamp is n burn+8 ,because a curr5t ( cold air f a w9d[ or a door1 bl[s ^u !m4 ,does quicksilv] exp& :5 heat$8 ,l o!r metals1 quicksilv] exp&s z x gr[s w>m]1 & contracts z x gr[s cool]4 ,is quicksilv] 9 ! =m ( a solid or a fluid8 ,x is a fluid z we usually see x4 ,= :at is quicksilv] us$8 ,x is us$ = fill+ ! tubes ( !rmomet]s4 ,:at is a ,!rmomet]8 ,x is an in/rum5t us$ = measur+ ! degree or quantity ( heat 9 any sub/ance4 ,h[ does heat affect ! quicksilv]8 ,heat exp&s ! quicksilv]1 & causes x to rise 9 ! tube4 ,h[ does cold affect ! quicksilv]8 ,cold contracts ! quicksilv]1 & causes x to fall 9 ! tube4 ,does heat exp& liquids m ?an solids8 ,heat does exp& liquids m ?an solids4 ,:y are liquids exp&$ m ?an solids8 ,because ! p>ticles ( :i* !y are =m$ are m easily sep>at$ or pu%$ ap>t by ! heat4 ,if we cont9ue to apply heat to a liquid1 :at becomes ( x8 ,! liquid is *ang$ into a gas or vapor4 ,:at common example h we ( vapor8 ,wat]1 :5 heat$1 is turn$ into /eam4 ,m5tion "s gas4 ,! air we brea! is a gas4 ,h[ does heat affect ! air8 ,heat w>ms ! air & causes x to exp&4 ,d solids all exp& equally :5 heat$8 ,no2 "s solids exp& m ?an o!rs2 ?us1 z9c exp&s m ?an iron1 & iron m ?an glass4 ,d liquids all exp& equally :5 heat$8 ,no2 liquids1 al?\gh m s5sitive to heat1 d n exp& z equally z solids4 ,d gases exp& equally :5 heat$8 ,yes2 gases exp& uni=mly2 ?us1 #dia cubic in*es ( any gas1 if heat$ "o degree1 w become #dib cubic in*es4 ,if "o cup be fill$ ) lead1 & ano!r cup ( ! same size ) wat]1 :i* w weigh ! m1 ! lead or ! wat]8 ,! lead w weigh m ?an ! wat]4 ,:i* is ! heavi] sub/ance1 lead or wat]8 ,lead is heavi] ?an wat]4 ,:y d we say lead is heavi] ?an wat]8 ,because a cup full ( lead w weigh m ?an ! same cup fall ( wat]1 or any bulk ( lead w weigh m ?an an equal bulk ( wat]4 ,:y is cork light] ?an wat]8 ,because any bulk ( cork is light] ?an an equal bulk ( wat]2 a cup fill$ ) cork w weigh less ?an :5 x is fill$ ) wat]4 ,:5 lead is put 9 wat]1 :y does x s9k to ! bottom8 ,because ! lead is heavi] ?an an equal bulk ( wat]4 ,:5 cork is put 9 wat]1 :y does x rise to ! surface8 ,because ! cork is light] ?an an equal bulk ( wat]4 ,does heat increase ! weight ( any sub/ance8 ,heat does n increase ! weight ( any sub/ance4 ,h[ d we "k ?is8 ,because a piece ( iron :5 cold w weigh z mu* z :5 heat$ r$-hot4 ,:5 a liquid is heat$1 does x become light] or heavi]8 ,x becomes light]1 bulk = bulk1 :5 heat$4 ,:y does a liquid become light] :5 heat$8 ,because ! same liquid is exp&$ & takes up m room1 al?\gh x has no m weight4 ,:y w a gallon ( cold wat] weigh m ?an a gallon ( hot wat]8 ,because a gallon ( cold wat]1 :5 heat$1 w make m ?an a gallon ( hot wat]4 ,:5 d we get ! mo/ molasses1 by buy+ x 9 hot or 9 cold wea!r8 ,we get ! mo/ by buy+ x 9 cold wea!r1 because a gallon b\ght !n w make m ?an a gallon :5 ! wea!r becomes w>m]4 ,does heat exp& ! air & make x light]8 ,heat does exp& ! air & make x light]4 ,:at does ! air d :5 heat$8 ,x asc5ds or rises up1 because x is light]1 & ! cold or heavi] air falls to take its place4 ,:at "p ( a room1 9 :i* !re is fire1 is ! w>me/8 ,! "p next to ! ceil+ is ! w>me/1 because ! heat$ air always asc5ds4 ,:y does a soap-bubble asc5d8 ,because x is fill$ ) heat$ air f ! lungs1 & is1 !re=e1 light] ?an ! air ar\nd x4 ,:y d balloons asc5d8 ,because !y are fill$ ) a gas light] ?an ! air ar\nd !m4 ,:y does a *e/nut split op5 :5 roa/+8 ,because ! air 9 x is exp&$ by ! heat1 s t x bur/s ! %ell4 ,:y does ! *e/nut n split op5 :5 a hole is made 9 ! %ell8 ,because ! air c !n escape z x exp&s1 )\t bur/+ ! %ell4 ,:at becomes ( ! air 9 an apple1 :5 ! apple is roa/$8 ,! air1 ^u be+ heat$1 bur/s ?r\gh ! peel ( ! apple1 c>ry+ ! juice ) x4 ,:y does an apple become s(t :5 roa/$8 ,because ! air 9 ! cells ( ! apple exp&s1 & breaks ^? cells1 s t ! apple becomes s(t4 ,:at "p ( ! apple fir/ becomes s(t8 ,! outside1 because x is fir/ heat$4 ,:y d all fruits & vegetables become s(t :5 cook$8 ,because ! heat exp&s ! air 9 !m1 & ?us breaks up _! cells1 s t !y become s(t4 ,:y does wood make a snapp+ noise :5 burn+8 ,because ! air 9 ! cells ( ! wood bur/s !m ap>t1 ?us mak+ ! noise4 ,:y are sp>ks ( fire ?r[n out8 ,because ! heat$ air bur/s ! cells ) su* =ce z to ?r[ (f small pieces ( ! burn+ wood4 ,:at k9ds ( wood snap ! mo/8 ,! co>se-gra9$ k9ds1 l *e/nut2 :ile ! f9]-gra9$ k9ds1 l walnut1 seldom snap mu*4 ,:y does dry wood snap m ?an gre5 wood8 ,because ! sap 9 ! pores ( ! gre5 wood dries up z ! wood becomes dry1 & its place is fill$ ) air1 s t !re is m air 9 dry wood ?an 9 gre5 wood4 ,:y does smoke rise 9 a *imney8 ,because ! air 9 ! *imney is heat$ by ! fire1 & z ! air rises1 x c>ries ! smoke ) x4 ,:y does a *imney smoke :5 ! fire is fir/ k9dl$8 ,because ! cold walls ( ! *imney cool ! heat$ air s rapidly z to prev5t its ris+ to ! top1 & ! smoke !n s9ks back into ! room4 ,h[ are h\ses heat$ ) hot air8 ,by hav+ ! fires made 9 ! cell>1 s t ! air :5 heat$1 may asc5d ?r\gh pipes to ! diff]5t p>ts ( ! build+4 ,is !re any sub/ance t does n contract by cold8 ,yes2 wat]1 :5 ne> freez+1 does n contract by cold4 ,:at takes place ) ! wat]8 ,:5 x is r$uc$ ne>ly to ! freez+ po9t1 x beg9s to exp&1 & :5 x freezes1 x exp&s /ill m4 ,h[ mu* does wat] exp& by freez+8 ,x exp&s ab\t "o-sev5? ( its bulk4 ,t is1 sev5 gallons ( wat] w make eight gallons ( ice4 ,does freez+ wat] exp& ) mu* =ce8 ,yes2 x exp&s ) great =ce4 ,:y are vessels conta9+ wat] (t5 brok5 dur+ a cold night8 ,z ! wat] 9 !m freezes1 x exp&s & breaks ! vessels4 ,:y d lead pipes & iron pipes (t5 bur/ dur+ ! w9t]8 ,because ! wat] 9 !m is p]mitt$ to freeze1 & z !re is n room = x to exp&1 ! pipes are bur/4 ,is ice heavi] or light] ?an wat]8 ,ice is light] ?an ! same bulk ( wat]4 ,h[ mu* light] is ice ?an wat]8 ,eight gallons ( ice weigh no m ?an sev5 gallons ( wat]4 ,does ! ice protect ! wat] b5ea? x f freez+8 ,ice does protect ! wat] f freez+1 to a v great ext5t4 ,if ice 7 heavi] ?an wat]1 :at w\ld result8 ,! ice w\ld s9k z rapidly z =m$1 & our /reams w\ld1 e w9t]1 freeze to ! bottom1 ?us de/roy+ ! fi% & o!r creatures liv+ 9 !m4 ,9 ?is1 z 9 _m o!r ways1 we may le>n ! lesson1 t 9 ! creation ( ! _w1 ,god wisely made all ?+s to s]ve "s useful purpose4 ,conduction ( ,heat4 ,:y does iron feel cold to ! t\* on a cold morn+8 ,because heat goes f ! h& to ! iron1 ?us giv+ ! s5sation ( cold4 ,:at is ! passage ( heat f ! h& to ! iron call$8 ,x is call$ conduction4 ,:5 "o end ( a rod ( iron is plac$ 9 a fire1 does ! :ole rod become heat$8 ,! :ole rod does become heat$4 ,h[ does ?is take place8 ,! heat ( ! fire passes f "o p>ticle to ano!r ?r\gh\t ! rod4 ,:at is ?is call$8 ,x is call$ conduction4 ,:at !n is conduction ( heat8 ,x is ! passage ( heat f "o body to ano!r :i* x t\*es1 or f "o p>ticle ( a body to ano!r p>ticle ( ! same body4 ,:at bodies are good conductors ( heat8 ,su* bodies z gold1 plat9um1 copp]1 silv]1 iron1 z9c1 t91 & lead1 9 ! ord] nam$1 are ! be/ conductors ( heat4 ,:at bodies are poor conductors ( heat8 ,su* bodies z glass1 wood1 *>coal1 wool1 hair1 & fur4 ,fur is ! poore/ conductor ( heat kn[n4 ,:y does a piece ( wood blaz+ at "o end n feel hot at ! o!r end8 ,because wood is a poor conductor1 & ! heat goes sl[ly ?r\gh x4 ,:y does a piece ( iron feel cold 9 w9t]8 ,because ! iron is a good conductor1 & c>ries ! heat away f our h&s v rapidly4 ,:y does fur feel w>m] ?an iron 9 ! w9t]8 ,because ! fur is a poor conductor1 & c>ries ! heat away f our h&s v sl[ly4 ,:y does a wood5 pump-h&le seem less cold ?an "o ( iron8 ,because wood is n s good a conductor z iron2 h5ce1 x does n c>ry ! heat ( our h&s away s rapidly4 ,:y does c>pet seem w>m] ?an ! b>e floor8 ,because ! c>pet is a poor] conductor ?an ! wood ( ! floor1 & does n c>ry away ! heat ( our bodies s rapidly4 ,:y does a /one pavem5t make our feet cold 9 w9t]8 ,because ! /one is a good conductor1 & rapidly c>ries ! heat away f our feet4 ,:y does heat$ iron feel hot to u8 ,because ! iron is a good conductor1 & gives (f its heat rapidly to our bodies4 ,:y does a piece ( clo?1 :5 heat$1 n feel hot8 ,because ! clo? is a poor conductor1 & gives (f its heat v sl[ly4 ,:y w a block ( wood1 :5 heat$1 rema9 hot long] ?an a heat$ brick8 ,because wood is a poor] conductor ?an brick1 & does n give (f its heat s rapidly4 ,:y is a block ( wood bett] ?an iron or brick1 to keep our feet w>m :ile on a j\rney8 ,because x does n give (f its heat s rapidly1 & !re=e rema9s w>m long] ?an iron or brick4 ,:y %\ld ! wood or brick be wrapp$ 9 clo?8 ,because ! clo?1 be+ a poor conductor1 helps to keep ! heat f pass+ (f s rapidly4 ,:y does iron feel cold] ?an wat] :5 bo? are at ! same temp]ature8 ,because iron is a bett] conductor ?an wat]1 & c>ries away ! heat f our h&s m rapidly4 ,are liquids good conductors ( heat8 ,no2 liquids are poor conductors ( heat4 ,is air a good conductor ( heat8 ,no2 air is a poor conductor ( heat4 ,are gases z good conductors z liquids8 ,no2 gases are poor] conductors ?an liquids4 ,:y is wat] a bett] conductor ?an air8 ,because ! p>ticles ( wat] are clos] toge!r ?an ! p>ticles ( air4 ,:y is iron a bett] conductor ?an wat]8 ,because ! p>ticles ( iron are clos] toge!r ?an ! p>ticles ( wat]4 ,h[ d we "k t wat] is a poor conductor ( heat8 ,because wat] may be made to boil at its surface )\t melt+ ice a %ort di/ance bel[ ! surface4 ,h[ d we "k t air is a poor conductor ( heat8 ,because ! air at ! ceil+ ( a room may be made v w>m )\t melt+ ice ne> ! floor4 ,:y does a l95 %irt feel cool8 ,because l95 is a good conductor1 & !re is b little air among its fibres4 ,:y is a cotton %irt w>m] ?an "o made ( l958 ,because ! cotton conta9s m air among its fibres1 & air is a poor conductor ( heat4 ,:y is a wooll5 %irt w>m] ?an "o made ( cotton8 ,because wool conta9s m air among its fibres1 & is1 !re=e1 a poor] conductor ( heat4 ,:y is fur w>m] ?an wool8 ,because !re is m air among ! hairs ( ! fur1 & x is1 !re=e1 a poor] conductor ( heat4 ,:at fur is ! w>me/8 ,fur ) v f9e hairs1 l t ( ! rabbit1 because x conta9s ! mo/ air4 ,:y is fur w>m] :5 ! hair is next to our bodies8 ,because ! fur & ! air 9 x bo? help to keep ! heat ( our bodies f pass+ (f rapidly4 ,is ! e>? a good conductor ( heat8 ,no2 ! e>? is a poor conductor ( heat4 ,h[ d we "k t ! e>? is a poor conductor ( heat8 ,because ! heat ( summ] w>ms ! e>? only a few in*es bel[ ! surface4 ,h[ is x ) ! e>? 9 w9t]8 ,9 ?is latitude1 ! fro/ ( w9t] rea*es only a few in*es bel[ ! surface ( ! e>?4 ,9 all p>ts ( ! e>?1 except 9 ! ,frigid ,zones1 ! heat ( ! summ] takes away ! fro/ & ice ( ! w9t]1 & ! e>? is w>m$ s t plants may gr[4 ,:y is spr+-wat] g5]ally cool1 ev5 9 summ]8 ,because ! spr+s are mo/ly s f> bel[ ! surface ( ! e>?1 t !y are n w>m$ by ! sun's rays4 ,:y is sn[ a w>m cov]+ = ! e>?8 ,because ! air among ! p>ticles ( sn[ prev5ts ! heat ( ! e>? f pass+ (f rapidly4 ,:y does wrapp+ /raw ar\nd a pump 9 w9t]1 prev5t ! wat] 9 x f freez+8 ,because ! /alks ( /raw are holl[1 & ! air 9 ! /alks makes !m poor conductors ( heat4 ,w /raw1 wrapp$ ar\nd %rubb]y1 prev5t x f freez+8 ,x w2 because x keeps ! heat ( ! %rubb]y f pass+ (f into ! air4 ,:y are rooms w>m] f hav+ d\ble w9d[s8 ,because ! air :i* is conf9$ betwe5 ! d\ble w9d[s1 be+ a poor conductor1 keeps ! w>m? ( ! room f escap+4 ,:y is ! space betwe5 ! d\ble walls ( ice-cool]s fill$ ) *>coal8 ,because *>coal is a poor conductor1 & keeps ! heat ( ! air f ! ice4 ,:y d ice-h\ses h d\ble walls1 ) saw-du/ or /raw betwe5 !m8 ,because ! saw-du/ & ! /raw are bo? poor conductors1 & keep ! heat ( ! air f ! ice4 ,:y does ice melt m sl[ly :5 wrapp$ 9 flannel8 ,because ! flannel is a poor conductor1 & keeps ! heat ( ! air f ! ice4 ,:y are wooll5 hold]s us$ ab\t ! /ove8 ,because wool is a poor conductor1 & ?us keeps ! heat ( ! iron f burn+ ! h&4 ,convection ( ,heat4 ,:5 air ne> ! floor ( a room is heat$1 :at becomes ( x8 ,x asc5ds to ! ceil+ ( ! room4 ,:at is done ) ! cold air at ! ceil+8 ,x desc5ds to ! floor1 to take ! place ( ! w>m air4 ,:5 ! air asc5ds to ! ceil+1 does x c>ry ! heat ) x8 ,yes2 x c>ries ! heat ) x4 ,:at is ?is mode ( c>ry+ heat call$8 ,x is call$ ,convection4 ,:at is ne$$ s z to heat a sub/ance by convection8 ,its p>ticles mu/ be able to move ab\t freely4 ,:y is ! air easily heat$ by convection8 ,because ! p>ticles ( ! air move ab\t freely4 ,:y is a liquid easily heat$ by convection8 ,because its p>ticles move ab\t freely4 ,:y _c a solid be heat$ by convection8 ,because its p>ticles _c move4 ,:5 wat] ne> ! bottom ( a vessel is heat$1 :at becomes ( x8 ,x rises to ! surface4 ,:at becomes ( ! cold wat] at ! surface8 ,x falls to ! bottom ( ! vessel1 to take ! place ( ! w>m wat]4 ,h[ long w ?is circulation cont9ue8 ,x w cont9ue s long z heat is appli$ to ! bottom ( ! vessel4 ,:5 heat is appli$ to ! surface ( ! wat]1 :at is ! result8 ,! wat] ne> ! surface only is heat$4 ,:y does x n heat all ! wat] 9 ! vessel8 ,because ! wat] :5 heat$1 becomes light]1 & /ays at ! surface1 :ile ! cold wat] is heavi] & rema9s at ! bottom ( ! vessel4 ,:]e mu/ heat be appli$ to w>m a liquid or a gas8 ,x mu/ be appli$ to ! bottom ( ! vessel conta9+ ! liquid or ! gas4 ,:]e mu/ a fire be1 s z to w>m a room8 ,! fire mu/ be ne> ! floor ( ! room4 ,:y does a hot sub/ance cool quickly 9 ! air8 ,because ! air t\*+ a sub/ance asc5ds z soon z heat$1 & cold air takes its place2 z ?is process goes on rapidly1 ! sub/ance is quickly cool$4 ,h[ is wat] cool$ by convection8 ,! wat] at ! surface is cool$ by giv+ (f its heat to ! air2 x !n falls to ! bottom1 & ! w>m wat] rises to take its place at ! surface4 ,:y does /irr+ hot c(fee cool x quickly8 ,because ! hot c(fee at ! bottom ( ! vessel1 is br\ght m rapidly 9 contact ) ! air1 &1 !re=e1 gives (f its heat m rapidly4 ,:y does bl[+ hot c(fee cool x quickly8 ,because ! hot air ov] ! c(fee is remov$ by bl[+1 & ! cold air is br\ght m rapidly 9 contact ) ! c(fee4 ,liquefaction4 ,is ice a solid or a liquid8 ,ice is a solid4 ,:5 heat is appli$ to ice1 :at becomes ( ! ice8 ,! ice is *ang$ into wat]4 ,is wat] a liquid8 ,wat] is a liquid4 ,h[ !n c a solid be *ang$ to a liquid8 ,by apply+ heat to a solid1 x may be *ang$ to a liquid4 ,:at is meant by liquefaction8 ,liquefaction is ! *ang+ ( a solid to a liquid1 by heat4 ,h[ may tall[ be melt$8 ,by heat+ ! tall[1 x may be melt$4 ,w ! tall[ become h>d aga9 :5 cold8 ,x w be h>d aga9 :5 cold4 ,c lead & o!r metals be melt$8 ,!y c be melt$ or *ang$ to a liquid /ate by heat4 ,c all solids be *ang$ to liquids8 ,no2 !re are _m solids1 su* z wood1 coal1 pap]1 & lea!r1 t _c be *ang$ to liquids4 ,h[ c a liquid be *ang$ to a solid8 ,by tak+ heat away f ! liquid1 x may be *ang$ to a solid4 ,:y is a solid melt$ by heat8 ,because heat =ces ! p>ticles ( ! solid ap>t1 until x is *ang$ to a liquid4 ,illu/ration3 ,decoration4 ,lat5t ,heat4 ,:y does w>m iron feel w>m to ! h&8 ,because x gives (f "s ( its heat to ! h&4 ,is ! h& s5sible ( ! heat com+ f ! iron8 ,! h& is s5sible ( ! heat4 ,:at !n may ?is heat be call$8 ,x may be call$ s5sible heat1 because x c be felt4 ,h[ d we measure heat8 ,we measure heat by degrees4 ,h[ _m degrees ( heat 9 ice :5 at ! melt+ po9t8 ,?irty-two degrees ( heat1 z measur$ by ! !rmomet]4 ,h[ c we *ange ice into wat]8 ,by apply+ heat to ! ice x w be *ang$ into wat]4 ,h[ _m degrees ( heat are necess>y to *ange ! ice into wat]8 ,"o hundr$ & =ty degrees ( heat are necess>y4 ,h[ _m degrees ( heat are 9 ! wat] :5 ! ice is all melt$8 ,only ?irty-two degrees ( heat1 by ! !rmomet]4 ,does ! wat] feel any w>m] ?an ! ice to ! h&8 ,no2 ! wat] does n feel any w>m] ?an ! ice4 ,:at has become ( ! "o hundr$ & =ty degrees ( heat8 ,!y h be5 hidd5 9 ! wat]4 ,:at is ?is hidd5 heat call$8 ,x is call$ lat5t heat4 ,:at is lat5t heat8 ,x is heat t is n s5sible to ! t\*1 or to ! !rmomet]4 ,:5 wat] is made to boil1 :at *ange takes place8 ,! wat] is *ang$ into /eam4 ,h[ _m degrees ( heat are necess>y to *ange wat] into /eam8 ,m ?an n9e hundr$ degrees ( heat are necess>y4 ,h[ _m degrees ( lat5t heat 9 /eam8 ,m ?an n9e hundr$ degrees ( lat5t heat4 ,:5 /eam is *ang$ back aga9 to wat]1 :at becomes ( ! lat5t heat8 ,x passes (f to ! air & ! surr\nd+ objects1 & makes !m w>m]4 ,:5 wat] is *ang$ into ice1 :at becomes ( ! lat5t heat8 ,x passes (f to ! surr\nd+ objects & makes !m w>m]4 ,is freez+ a w>m+ process8 ,yes2 because ! wat] gives (f its lat5t heat :ile freez+2 h5ce1 ! surr\nd+ objects are made w>m]4 ,is ?aw+ a cool+ process8 ,yes2 because ! ice absorbs s mu* heat :ile ?aw+ t x cools ! surr\nd+ objects4 ,:]e does ! ice obta9 its heat1 :ile ?aw+8 ,! ice obta9s its heat f ! surr\nd+ objects4 ,are ^! objects made cool] by ! melt+ ( ! ice8 ,!y are made cool] by ! melt+ ( ! ice4 ,:at effect does salt h ^u ice8 ,salt makes ! ice melt m rapidly4 ,:5 salt & ice are plac$ ar\nd a vessel ( cream1 :at takes place8 ,! salt causes ! ice to melt quickly1 & ! ice 9 melt+ takes s mu* heat f ! cream z to freeze x1 ?us mak+ x ice-cream4 ,ebullition4 ,:at is meant by ebullition8 ,ebullition means boil+4 ,:5 is a liquid 9 a /ate ( ebullition8 ,:5 x has be5 heat$ s z to boil4 ,c solids be made to boil8 ,no2 liquids only c be made to boil4 ,:at *ange takes place :5 a liquid boils8 ,! liquid is *ang$ into a vapor or gas4 ,:at becomes ( wat] :5 x is boil$8 ,wat] :5 boil$ passes (f into /eam4 ,:at is necess>y to make wat] boil8 ,heat is necess>y to boil wat] or any o!r liquid4 ,h[ mu* heat is conta9$ 9 boil+ wat]8 ,two hundr$ & twelve degrees ( heat4 ,:5 wat] passes into /eam1 h[ mu* is its bulk increas$8 ,ab\t sev5te5 hundr$ times4 ,h[ mu* /eam w a p9t ( wat] make8 ,a p9t ( wat] w make ab\t sev5te5 hundr$ p9ts ( /eam4 ,:at d bubbles ( boil+ wat] conta98 ,!y conta9 /eam4 ,:y are ^! bubbles =m$8 ,because ! wat] at ! bottom ( ! vessel is heat$ & *ang$ into /eam1 :i* exp&s & =ms ! bubbles4 ,:y d ^! bubbles rise to ! surface8 ,because /eam is light] ?an wat]4 ,:5 does wat] simm]8 ,:5 wat] is heat$1 ! /eam at fir/ =ms 9 v small bubbles at ! bottom ( ! vessel1 & z ^! bubbles rise ?r\gh ! cold] wat]1 ! /eam 9 !m is cond5s$ to wat]1 s t !y break be=e rea*+ ! surface1 ?us produc+ :at is call$ 8simm]+40 ,:5 does wat] boil8 ,wat] boils :5 x becomes heat$ s t ! bubbles rise to ! surface ( ! wat] be=e break+4 ,:y w a vessel full ( wat] run ov] :5 heat$8 ,because ! wat] is exp&$ by heat1 & "s ( x mu/ run ov]4 ,:y w ! wat] boil ov] :5 ! vessel is n full8 ,because ! /eam1 9 try+ to escape1 ?r[s "s ( ! wat] ov] ! edge ( ! vessel4 ,vaporization4 ,:5 wat] is boil$1 :at *ange does x und]go8 ,x is *ang$ into a vapor1 call$ /eam4 ,:at is ?is process call$8 ,x is call$ ,vaporization4 ,:at is meant by vaporization8 ,vaporization is ! *ang+ ( a liquid into a vapor1 by boil+4 ,:at is necess>y to *ange a liquid into a vapor8 ,heat is necess>y to *ange a liquid into a vapor4 ,at :at temp]ature is wat] *ang$ into /eam8 ,at ! temp]ature ( two hundr$ & twelve degrees4 ,are all liquids *ang$ to vapor at ! same temp]ature8 ,no2 !y v>y v mu* 9 ! am\nt ( heat requir$4 ,e!r boils at #if degrees1 alcohol at #agf degrees1 & quicksilv] at a temp]ature ( #ffb degrees4 ,:5 wat] is *ang$ into /eam1 :at becomes ( ! /eam8 ,! /eam passes (f into ! air4 ,:at does ! air d ) ! /eam8 ,! air cond5ses or *anges x into v small p>ticles ( wat]1 s t x is se5 l a fog or a cl\d4 ,c /eam be se58 ,no2 /eam is l ! air 9 ?is respect1 & _c be se54 ,h[ c we prove ?is8 ,:5 wat] is boil$ 9 a glass vessel1 no /eam is visible1 al?\gh x is !re4 ,_c we see ! /eam com+ f ! sp\t ( a tea-kettle8 ,no2 we d n see any?+ = half an in* or m f ! sp\t4 ,:y does x become visible f>!r away8 ,because ! air cond5ses x1 & !n we see x 9 its cl\d-l /ate4 ,h[ mu* /eam w "o gallon ( wat] make8 ,"o gallon ( wat] w make sev5te5 hundr$ gallons ( /eam4 ,:5 ?is /eam is conf9$ 9 a vessel1 :at does x try to d8 ,x tries to exp& or spread out 9 e direction4 ,does x exp& ) mu* =ce8 ,yes2 x exp&s ) s mu* =ce z frequ5tly to bur/ ! vessel conta9+ x4 ,:y is ! lid ( ! tea-kettle lift$ up :5 ! wat] boils8 ,because ! /eam exp&s & raises ! lid1 s t x c escape4 ,if ! lid 7 fa/5$ d[n1 :at w\ld result8 ,! /eam1 9 try+ to escape1 w\ld bur/ ! tea-kettle4 ,:y does wat] run out ( ! sp\t ( ! tea-kettle8 ,because ! /eam 9 ! tea-kettle presses on ! wat] ) =ce en\gh to cause x to run out4 ,:y does /eam bur/ vessels 9 :i* x is conf9$8 ,because ! vessels are n /rong en\gh to keep ! /eam f exp&+4 ,h[ is ! boil] ( a /eam-eng9e kept f bur/+8 ,by means ( a safety-valve4 ,:at is a safety-valve8 ,x is a valve or op5+ ?r\gh :i* /eam may escape4 ,:at prev5ts all ( ! /eam f escap+ ?r\gh ! valve8 ,! valve is kept clos$ by a weight1 :i* prev5ts ! escape ( ! /eam until a c]ta9 quantity ( x is =m$ 9 ! boil]2 x !n lifts up ! valve1 & a portion ( x escapes1 ! same z x does ) ! lid ( ! tea-kettle4 ,evaporation4 ,does a wet blanket1 :5 hung 9 ! air1 rema9 wet8 ,no2 x soon becomes dry4 ,:at becomes ( ! wat] 9 ! blanket8 ,! wat] passes (f into ! air4 ,:at is ?is process call$8 ,x is call$ ,evaporation4 ,:at is meant by evaporation8 ,x is ! gradual *ange ( a liquid into a vapor4 ,:5 wat] is left 9 a %all[ vessel1 :at becomes ( x8 ,! wat] evaporates or passes (f into ! air4 ,d liquids g5]ally evaporate8 ,yes2 :5 expos$ to ! air1 ne>ly all liquids evaporate4 ,does wat] *ange into /eam :5 x evaporates8 ,wat] does n *ange into /eam :5 x evaporates4 ,h[1 !n1 does wat] evaporate8 ,x passes (f into ! air 9 p>ticles or drops s v small z n to be visible4 ,is evaporation always go+ on ar\nd u8 ,yes2 :]ev] !re is wat] expos$ to ! air1 evaporation is tak+ place4 ,:]e does ! mo/ evaporation take place8 ,f ! surface ( ! riv]s1 ! lakes1 & ! ocean4 ,:at becomes ( ! wat] :5 evaporat$8 ,x is =m$ into fogs & cl\ds4 ,9 :at k9d ( air does evaporation g on mo/ rapidly8 ,9 air t is w>m & dry4 ,does evaporation take place 9 cool air8 ,x does2 because clo?+ w dry dur+ ! colde/ wea!r ( w9t]4 ,:y does wat] evaporate m 9 w>m air ?an 9 cold air8 ,because ! w>m air c hold m ( ! f9e p>ticles ( wat]1 &1 !re=e1 c absorb m4 ,:y does wat] evaporate m sl[ly 9 damp wea!r ?an 9 dry wea!r8 ,because ! damp air conta9s s mu* moi/ure t b little m c pass (f into x4 ,:at example h we ( ?is8 ,wet clo!s dry mu* m sl[ly :5 ! air is damp ?an :5 x is dry4 ,:y d clo!s dry m rapidly 9 w9dy wea!r8 ,because ! damp air 9 contact ) !m is bl[n away1 & ! dry air is con/antly tak+ its place4 ,is heat necess>y 9 evaporation8 ,heat is necess>y to produce evaporation4 ,:y d our h&s feel cold :5 wet8 ,because ! wat] on our h&s evaporates1 & ?us heat is tak5 f !m4 ,:y is ! air cool] aft] a ra98 ,because evaporation !n takes place f e wet object1 & ?is absorbs heat f ! air4 ,:y does wat]+ /reets & roads cool ! air8 ,because ! wat] evaporates & absorbs heat f ! air1 mak+ x cool]4 ,:y d we feel cold :5 our clo!s are wet8 ,because ! moi/ure 9 !m evaporates & absorbs heat f our bodies4 ,:y is wet l& always cold8 ,because s mu* heat is absorb$ f ! l& 9 ! evaporation :i* is con/antly tak+ place4 ,:at becomes ( ! dew t collects on plants & o!r objects at night8 ,x is evaporat$4 ,h[ does ! sun ha/5 ! evaporation ( ! dew8 ,by supply+ ! heat ne$$ to *ange ! dew into a vapor1 ! sun ha/5s its evaporation4 ,:y d bread & biscuit become h>d :5 kept a few days8 ,because ! moi/ure 9 !m passes (f into ! air1 & ?us !y become dry & h>d4 ,h[ c !y be kept moi/ & s(t = a long] "t8 ,by keep+ !m 9 a cov]$ vessel1 s t evaporation w take place m sl[ly1 !y may be kept moi/ = a long] "t4 ,radiation4 ,:5 we /& ne> ! fire1 :y d we feel w>m8 ,because ! fire gives (f heat :i* makes u feel w>m4 ,h[ does ! fire give (f heat8 ,x gives (f heat 9 /raight l9es1 & 9 e direction4 ,:at is ?is giv+ (f ( heat call$8 ,x is call$ ,radiation ( heat4 ,does ! sun radiate heat8 ,! sun does radiate or give (f bo? heat & light4 ,h[ d heat & light f ! sun come to u8 ,!y come toge!r 9 ! sunbeam4 ,does heat travel z rapidly z light8 ,yes2 heat & light travel toge!r at ! rate ( #bjj1jjj miles 9 a second ( "t4 ,d all sub/ances radiate heat equally well8 ,no2 "s sub/ances are mu* bett] radiators ?an o!rs4 ,:at k9d ( objects are ! be/ radiators8 ,^? ) r\gh & d>k surfaces4 ,:at k9d ( objects are ! poore/ radiators8 ,^? ) smoo? & bright surfaces4 ,:y does wat] keep hot a long "t 9 a bright t9 vessel8 ,because ! t9 is a poor radiator1 & prev5ts ! heat ( ! wat] f pass+ (f into ! air4 ,:y does wat] soon cool 9 a dull e>!n vessel8 ,because ! e>!n vessel is a good radiator1 & gives (f ! heat ( ! wat] rapidly4 ,if ! bright t9 vessel be pa9t$1 w ! wat] keep hot s long8 ,no2 ! t9 becomes a good radiator :5 pa9t$1 & ! wat] is soon cool$4 ,:y does a /ove cool s quickly8 ,because ! iron is a good radiator1 & gives (f its heat rapidly4 ,d ! rays f ! sun give (f mu* heat :ile pass+ ?r\gh ! air8 ,! rays f ! sun give (f ab\t "o-f\r? ( _! heat :ile pass+ ?r\gh ! air4 ,:at becomes ( ! rema9+ heat f ! sun8 ,x is absorb$ or reflect$ at ! e>?'s surface4 ,:at does ! e>? d ) ! heat8 ,! e>? radiates ! heat1 & ?us w>ms ! air4 ,reflection4 ,:5 a piece ( bright t9 is held ne> ! fire1 does ! t9 become hot8 ,no2 ! t9 is sc>cely w>m$4 ,:at does ! t9 d ) ! rays ( heat f ! fire8 ,! t9 ?r[s !m back f its surface4 ,:at is ?is call$8 ,x is call$ ,reflection ( heat4 ,d all sub/ances reflect heat equally well8 ,no2 "s reflect mu* m heat ?an o!rs4 ,:at k9d ( objects reflect heat ! be/8 ,^? ) bright & smoo? surfaces4 ,:at k9d ( objects reflect heat ! lea/8 ,^? ) r\gh & d>k surfaces4 ,does bright t9 reflect heat bett] ?an glass8 ,yes2 bright t9 reflects ab\t eight times z mu* heat z glass does4 ,:y does x take s long to heat wat] 9 a new t9 cup8 ,because ! bright t9 is a good reflector1 & ?r[s (f ! great] "p ( ! rays ( heat t come to x f ! fire4 ,:y does a piece ( t9 or o!r bright metal1 plac$ "u a /ove1 protect ! c>pet f burn+8 ,because ! t9 be+ a good reflector1 rema9s cool1 & _c burn ! c>pet "u x4 ,:y w n a piece ( iron protect ! c>pet f burn+8 ,because ! iron1 be+ a poor reflector1 soon becomes heat$1 s z to burn ! c>pet "u x4 ,absorption4 ,:5 a piece ( iron is held ne> a fire1 does ! iron become hot8 ,yes2 ! iron soon becomes hot4 ,h[ is ! iron heat$8 ,! iron absorbs or takes 9 ! heat f ! fire4 ,:at is ?is p[] to take 9 ! heat call$8 ,x is call$ ,absorption ( heat4 ,:at is ?is process l8 ,x is some:at l a sponge1 t absorbs or sucks up moi/ure4 ,d all sub/ances absorb heat equally well8 ,no2 "s sub/ances absorb m heat ?an o!rs4 ,:at k9d ( objects absorb heat ! be/8 ,^? ) r\gh surfaces absorb heat ! be/4 ,:at k9d ( objects absorb heat ! lea/8 ,^? ) bright & smoo? surfaces4 ,:at color$ objects absorb heat ! be/8 ,objects ( a d>k or black color4 ,d objects t absorb heat well1 radiate well8 ,yes2 good absorb]s are good radiators4 ,:y is ?is8 ,because e sub/ance mu/ absorb heat be=e x c h heat to give (f4 ,d objects t absorb heat well1 reflect x well8 ,no2 objects t absorb heat well1 _c reflect x well4 ,:y is ?is8 ,because a ray ( heat _c be reflect$ f an object1 & be absorb$ by t object1 bo? at ! same "t4 ,:y is wat] rapidly heat$ 9 a tea-kettle8 ,because ! r\gh1 d>k iron ( ! tea-kettle absorbs ! heat f ! fire1 & gives x (f rapidly to ! wat] conta9$ 9 ! kettle4 ,! iron is also a good conductor ( heat2 !re=e1 ! heat f ! fire passes rapidly ?r\gh x to ! wat]4 ,:y does black clo?1 :5 spread on ! sn[1 cause ! sn[ to melt m rapidly8 ,because ! clo? absorbs heat f ! rays ( ! sun1 &1 !re=e1 melts ! sn[ b5ea? x4 ,:y does n :ite musl91 :5 spread on ! sn[1 ha/5 its melt+8 ,because ! :ite musl9 reflects ! heat f ! rays ( ! sun1 s t b little ( x ent]s ! sn[4 ,does ! sn[ receive mu* heat f ! sun8 ,sn[ is a good reflector1 & ?r[s back mo/ ( ! heat f ! sun4 ,:at causes ! sn[ to melt8 ,! heat x receives f t\*+ ! e>?1 causes ! mo/ ( x to melt4 ,:y does sn[ melt fir/ on d>k e>?8 ,because d>k e>? is a good radiator1 & gives (f mu* heat to ! sn[4 ,:y does sn[ rema9 longe/ on light-color$ e>?8 ,because ! light-color$ e>? is a poor radiator1 & gives (f b little heat to ! sn[4 ,:y does ! air feel cold 9 w9t] "t8 ,because x is s mu* cool] ?an our bodies t x absorbs heat f !m rapidly1 & ?us makes !m feel cold4 ,:y does ! air feel w>m 9 summ] "t8 ,because x is !n ne>ly z w>m z our bodies1 &1 !re=e1 absorbs heat f !m sl[ly4 ,:y are greasy %oes w>m] ?an ^? poli%$ ) black+8 ,because ! greasy %oes absorb heat f ! sun1 b ! poli%$ %oes ?r[ (f ! heat ( ! sun by reflection4 ,:at may we rememb] ab\t heat8 ,& ,god said1 ,let !re be light2 & !re 0 light4 ,b along ) ! light1 came its companion--heat2 = :5 ! sunbeam fir/ came =? at ,8 comm&1 ! tw9 si/]s1 light & heat1 toge!r t\*$ ! e>?1 caus+ x to bloom ) life & beauty4 ,& ! e>? br\ght =? grass1 ! h]b yield$ its se$1 & ! tree its fruit3 ,& ,god saw t x 0 all good4 ,illu/ration3 ,an outdoor walk4 ,illu/ration3 ,decoration4 ,,*apt] ,,iv4 ,! ,air4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:]e d we f9d air8 ,we f9d air ev]y:]e ar\nd ! e>?4 ,does ! air fill e place8 ,! air fills e place n fill$ by "s o!r sub/ance4 ,:5 we say a bottle is empty1 :at d we mean8 ,we mean t x does n conta9 any?+ b air4 ,:at d all vessels conta9 :5 empty8 ,all vessels conta9 air :5 seem+ly empty4 ,d all liquids conta9 air8 ,yes2 all liquids conta9 air4 ,:]e is ! air 9 a liquid8 ,! air is among ! p>ticles :i* compose ! liquid4 ,is !re air 9 wat]8 ,yes2 !re is air 9 wat]4 ,( :at use is ! air 9 ! wat]8 ,x is us$ by ! fi% & o!r creatures t live 9 ! wat]4 ,h[ d ! fi% & o!r creatures use x8 ,!y brea! x into _! lungs1 & x supports life 9 !m1 ! same z ! air :i* we brea! supports life 9 u4 ,d solids conta9 air8 ,yes2 solids conta9 m or less air4 ,:]e is ! air 9 fur & 9 wool8 ,x is among ! hairs ( ! fur & ! wool4 ,:]e is ! air 9 cotton & l95 goods8 ,x is among ! fibres ( ! cotton & ! l954 ,:]e is ! air 9 fruit8 ,x is among ! p>ticles compos+ ! fruit4 ,:]e is ! air 9 wood8 ,x is 9 ! pores or small spaces 9 ! wood4 ,is !re air 9 ! e>?8 ,yes2 !re is air among ! p>ticles ( ! e>?4 ,h[ deep 9 ! e>? does ! air ext5d8 ,we _c tell2 b bo? air & wat] h be5 f\nd sev]al hundr$ feet bel[ ! e>?'s surface4 ,( :at use is ! air 9 ! e>?8 ,x is brea!d by ! worms & o!r creatures t live 9 ! e>?4 ,:5 "p ( ! air is tak5 f a room1 :at becomes ( ! air left 9 ! room8 ,x exp&s s z to fill ! :ole room4 ,are ! p>ticles ( air s close toge!r aft] x exp&s z !y 7 be=e8 ,!y are n s close toge!r4 ,:5 air is ?us exp&$1 :at is said ( x8 ,x is said to be r>e4 ,:5 pressure is put ^u air 9 a vessel1 :at becomes ( ! air8 ,x is =c$ or press$ into a small] space1 &1 !re=e1 occupies less room4 ,:5 pressure is put ^u air1 are its p>ticles clos] toge!r8 ,!y are clos] toge!r4 ,:5 air is ?us compress$1 :at is said ( x8 ,x is said to be d5se4 ,c air be mu* cond5s$ by pressure8 ,x has be5 cond5s$ s mu* t #ajj cubic feet ( air 0 r$uc$ to ! bulk ( only "o cubic foot4 ,:at makes ! air s d5se z x is at ! surface ( ! e>?8 ,! pressure ( ! air above ! surface4 ,does ! air !n become less d5se ! high] we asc5d8 ,yes2 because !re is less air above to press ^u x4 ,does ! air become m d5se ! deep] we g 9 ! e>?8 ,x does2 because !re is m air above to press ^u x4 ,h[ c we und]/& ?is8 ,9 a l>ge heap ( wool1 ! hairs ( ! wool at ! bottom ( ! heap are press$ closely toge!r1 b !y are f>!r & f>!r ap>t ! ne>] !y are to ! top ( ! heap4 ,h[ high does ! air ext5d above ! e>?8 ,x is suppos$ to ext5d to ! height ( fifty miles4 ,d ^! fifty miles ( air press ^u ! e>?8 ,!y d press ^u ! e>?4 ,) h[ mu* =ce does ! air press on ! e>?8 ,) a =ce ( fifte5 p\nds on e squ>e in* ( surface4 ,!n has ! air weight8 ,! air has weight4 ,:y d we n feel ! weight ( ! air8 ,because x presses ) equal =ce1 9 e direction2 up1 d[n1 & on e side4 ,h[ c we %[ t ! air presses upw>ds8 ,fill a tumbl] ) wat] & put a piece ( writ+-pap] ov] ! top4 ,hold ! h& on ! pap] & quickly inv]t ! tumbl]1 or turn x bottom upw>ds2 !n remove ! h&1 & ! pressure ( ! air aga9/ ! pap] w keep ! wat] 9 ! tumbl]4 ,?is is repres5t$ 9 ,fig4 #ab4 ,illu/ration3 ,fig4 #ab4 ,if a tumbl] be fill$ ) wat] 9 a bucket1 & !n rais$ bottom upw>ds until its edge is j bel[ ! surface ( ! wat]1 x w rema9 full ( wat]2 :y is ?is8 ,! pressure ( ! air on ! wat] 9 ! bucket1 keeps ! wat] 9 ! tumbl]4 ,if we use an iron pipe or a lead pipe1 in/ead ( a tumbl]1 w ! pressure ( ! air keep ! wat] 9 ! pipe8 ,x w1 ! same z x keeps x 9 ! tumbl]4 ,h[ high w ! air keep ! wat] 9 ! pipe8 ,x w keep ! wat] to ! height ( ?irty-f\r feet4 ,:y does ! air keep ! wat] up ?irty-f\r feet8 ,because ! air presses d[n ) a =ce ( fifte5 p\nds on e squ>e in* ( surface1 & a column ( wat] ?irty-f\r feet high presses d[n ) a =ce ( fifte5 p\nds on e squ>e in* ( surface4 ,does ! weight ( ! air exactly balance ! weight ( ! column ( wat]8 ,x does2 !y balance ea* o!r4 ,is wat] heavi] ?an air8 ,wat] is heavi] ?an air2 because a column ( wat] ?irty-f\r feet high weighs z mu* z a column ( air fifty miles high4 ,is quicksilv] heavi] ?an wat]8 ,yes2 quicksilv] is ab\t ?irte5 times heavi] ?an wat]4 ,h[ high a column ( quicksilv] c ! air keep up8 ,! air c keep up a column ( quicksilv] only ?irty in*es high4 ,:y is ?is8 ,because a column ( quicksilv] ?irty in*es high1 weighs exactly ! same z a column ( air fifty miles high1 or a column ( wat] ?irty-f\r feet high4 ,h[ c ?is be %[n8 ,take a glass tube ab\t ?irty-?ree in*es long1 cork up "o end1 & fill ! tube ) quicksilv]2 !n put ! op5 end ( ! tube b5ea? ! surface ( "s quicksilv]1 9 a bas91 & ! quicksilv] 9 ! tube w fall to ! height ( ?irty in*es1 z is %[n 9 ,fig4 #ac4 ,illu/ration3 ,fig4 #ac4 ,if ! cork be remov$ f ! glass tube1 :at w become ( ! quicksilv]8 ,x w imm$iately s9k into ! bas9 bel[4 ,:y w ! quicksilv] s9k into ! bas98 ,because ! air w !n press ^u ! quicksilv] 9 ! tube1 ! same z x does on t 9 ! bas92 h5ce1 all ! quicksilv] w fall to ! same level4 ,does ! weight ( ! air v>y at diff]5t times8 ,yes2 ! air does v>y 9 weight at diff]5t times4 ,h[ c we tell :5 ! air *anges 9 weight8 ,by means ( a ,b>omet]4 ,:at is a b>omet]8 ,x is an in/rum5t hav+ a tube fill$ ) quicksilv]4 ,:5 ! air is heavi]1 h[ does x affect ! quicksilv]8 ,! quicksilv] rises 9 ! tube4 ,:5 ! air is light]1 h[ does x affect ! quicksilv]8 ,! quicksilv] s9ks 9 ! tube4 ,:at is ! use ( ! b>omet]8 ,x %[s ! *anges ab\t to take place 9 ! wea!r4 ,:5 ! quicksilv] rises1 :at k9d ( wea!r is indicat$8 ,x indicates fair wea!r4 ,:5 ! quicksilv] s9ks1 :at k9d ( wea!r is indicat$8 ,x indicates cl\dy or /ormy wea!r4 ,:]e is ! b>omet] mo/ useful8 ,x is mo/ useful at sea1 to w>n ! sailors ( com+ /orms4 ,:at use is x to f>m]s8 ,!y c use x z a guide :5 plant+ & ga!r+ _! crops1 & ?us be bett] prep>$ = /ormy wea!r4 ,= :at else may ! b>omet] be us$8 ,x may be us$ to tell ! height or dep? ( any place4 ,does ! air become light] z we asc5d8 ,! air does become light] z we asc5d4 ,h[ does ?is affect ! b>omet]8 ,z ! air becomes light]1 ! quicksilv] 9 ! b>omet] s9ks l[]4 ,at :at height does ! quicksilv] /& at ! level ( ! sea8 ,x /&s at ! height ( ?irty in*es4 ,:5 we asc5d a m\nta9 #aj1jjj feet high1 h[ mu* does ! quicksilv] s9k8 ,x s9ks t5 in*es1 &1 !re=e1 /&s at ! height ( only tw5ty in*es4 ,does ! same ?+ take place :5 we asc5d 9 a balloon8 ,yes2 ! high] ! balloon asc5ds1 ! l[] ! quicksilv] 9 ! b>omet] s9ks4 ,:5 we desc5d into ! m9es dug 9 ! e>?1 does ! air become heavi]8 ,x does2 & ! quicksilv] 9 ! b>omet] rises4 ,at :at temp]ature does wat] boil8 ,wat] boils at a temp]ature ( two hundr$ & twelve degrees4 ,:5 ! weight ( ! air is tak5 (f1 w ! wat] boil at a l[] temp]ature8 ,wat] w !n boil at a l[] temp]ature4 ,:]e w wat] boil at ! l[e/ temp]ature1 on a m\nta91 or 9 a valley8 ,x w boil at ! l[e/ temp]ature on a m\nta94 ,at h[ mu* l[] temp]ature w wat] boil1 z we asc5d8 ,wat] w boil at "o degree less = e five hundr$ feet we asc5d4 ,h[ high is ! city ( ,quito1 9 ,s\? ,am]ica8 ,quito is n9e ?\s& feet above ! level ( ! sea4 ,at :at temp]ature does wat] boil !re8 ,wat] boils1 9 ,quito1 at a temp]ature ( "o hundr$ & n9ety-f\r degrees4 ,w an egg boil h>d at ,quito8 ,no2 because ! wat] passes (f into /eam at "o hundr$ & n9ety-f\r degrees1 & x requires m ?an "o hundr$ & n9ety-f\r degrees ( heat to boil an egg h>d4 ,d p]sons1 :ile asc5d+ m\nta9s1 (t5 h difficulty 9 cook+ _! food8 ,!y d1 on acc\nt ( wat] boil+ !re at a temp]ature bel[ two hundr$ & twelve degrees4 ,:at is a vacuum8 ,a vacuum is a place t does n conta9 any?+1 n ev5 air4 ,:5 a vessel conta9s wat] & we p\r ! wat] out1 does t produce a vacuum8 ,no2 because air passes 9 & fills ! vessel4 ,h[ !n c a vacuum be produc$8 ,a vacuum 9 any place1 c be produc$ only by draw+ ! air out ( x4 ,:5 a vacuum is produc$1 :at does ! surr\nd+ air try to d8 ,x tries to get 9 s z to fill ! vacuum4 ,) :at =ce does ! air try to fill a vacuum8 ,) a =ce ( fifte5 p\nds on e squ>e in* ( surface4 ,:5 a vacuum is produc$ 9 contact ) a liquid1 :at does ! liquid d8 ,! liquid tries to pass 9 to fill ! vacuum4 ,c !re be a vacuum 9 contact ) a gas or a liquid8 ,no2 because ! gas or ! liquid w in/antly fill ! vacant space4 ,:y does wat] make a gurgl+ noise :5 p\r$ out ( a bottle8 ,because air is pass+ into ! bottle at ! same "t t ! wat] is com+ out1 & ! air makes ! noise 9 pass+ ?r\gh ! wat]4 ,:y does wat] make a gurgl+ noise :5 runn+ out ( a b>rel8 ,because ! air passes into ! b>rel at ! op5+ :]e ! wat] passes out1 & ?us ! noise is made4 ,h[ c ! gurgl+ noise be prev5t$8 ,by mak+ an op5+ at ! top ( ! b>rel1 s z to admit ! air4 ,does wat] fl[ freely f a vessel t has b "o op5+8 ,no2 because "p ( ?is op5+ is ne$$ to admit air into ! vessel4 ,:y does ! wat] fl[ freely1 :5 !re is an op5+ at ! top z well z at ! bottom ( ! vessel8 ,because air is admitt$ at ! top1 & !re is !n no?+ to ob/ruct ! fl[ ( wat] f ! op5+ at ! bottom4 ,:at causes fruit1 vegetables1 & meat to spoil8 ,! air causes !m to spoil4 ,h[ d we "k ?is8 ,because :5 kept f ! air !y rema9 good = a long "t4 ,:at is ?is process ( keep+ fruit call$8 ,x is call$ cann+4 ,h[ is fruit cann$8 ,! fruit is put into a glass j>1 or into a t9 c1 along ) "s wat]1 & !n heat$ until ! j> or c is fill$ ) /eam & ! air is all =c$ out2 x is !n seal$ s z to be air-tight1 &1 9 ?is condition1 may be kept = _m mon?s4 ,:at becomes ( ! /eam 9 ! j> or c8 ,z ! fruit cools1 ! /eam is cond5s$ to wat]1 & a vacuum is produc$1 s t ! fruit is kept f ! air4 ,:at is ! play?+ :i* boys call a suck]8 ,a suck] is a r\nd piece ( lea!r1 ) a /r+ fa/5$ to its c5tre4 ,h[ is ! suck] us$8 ,! lea!r is made v s(t & wet1 s t :5 press$ aga9/ a /one or brick1 all ! air "u ! lea!r is =c$ out2 & :5 ! lea!r is lift$ up1 ! /one or brick is lift$ ) x1 z is repres5t$ by ,fig4 #ad4 ,illu/ration3 ,fig4 #ad4 ,:at keeps ! lea!r aga9/ ! /one8 ,! pressure ( ! air ^u ! lea!r keeps x aga9/ ! /one4 ,) h[ mu* =ce does ! air press ! lea!r aga9/ ! /one8 ,) a =ce ( fifte5 p\nds on e squ>e in*4 ,:5 !re is air betwe5 ! /one & ! lea!r1 c ! /one be lift$ ) ! suck]8 ,x _c2 because ! air "u ! lea!r w press x up z mu* z ! air above w press x d[n4 ,h[ does a fly walk ^u ! ceil+8 ,! fly's feet are mu* l ! suck]1 & are kept aga9/ ! ceil+ by ! pressure ( ! air4 ,h[ d snails cl+ to objects8 ,!y =ce out all ! air betwe5 ! object & _! bodies1 & are !n held aga9/ ! object1 z ! suck] is held aga9/ ! /one4 ,:at is a siphon8 ,a siphon is a b5t tube1 hav+ "o bran* long] ?an ! o!r1 z is repres5t$ 9 ,fig4 #ae4 ,illu/ration3 ,fig4 #ae4 ,= :at is ! siphon us$8 ,! siphon is us$ to draw liquids f "o vessel into ano!r4 ,h[ c wat] be drawn f a vessel by means ( a siphon8 ,put ! %ort bran* 9 ! wat]1 !n1 by means ( ! m\? appli$ to ! long bran*1 suck ! air f x1 & ! wat] w beg9 imm$iately to fl[ f ! long bran*4 ,:]e mu/ ! op5 end ( ! %ort bran* be kept8 ,x mu/ be kept b5ea? ! surface ( ! wat]1 s z to prev5t air f ent]+ ! tube4 ,:]e mu/ ! op5 end ( ! long bran* be kept8 ,x mu/ be kept l[] ?an ! op5 end ( ! %ort bran*4 ,:ile ! wat] is runn+ out ( ! long bran*1 :at is produc$ at ! b5d ( ! tube8 ,! t5d5cy is to produce a vacuum at ! b5d ( ! tube4 ,:at is ! result ( ?is8 ,! wat] is cont9ually =c$ up ! %ort bran* to fill ?is vacuum1 s t x runs out ( ! long bran* 9 a /eady /ream4 ,h[ d boys (t5 suck cid] f a b>rel8 ,by means ( a /raw4 ,h[ is ?is done8 ,"o end ( ! /raw is plac$ 9 ! cid]1 & ! o!r end 9 ! m\?2 !n ! air is suck$ out ( ! /raw1 & ! cid] is =c$ up to fill ! vacuum4 ,:5 ! cid] is suck$ out1 m cid] is =c$ up1 s t ! /raw is kept full4 ,:at makes ! cid] rise to fill ! vacuum 9 ! /raw8 ,! pressure ( ! air on ! cid] 9 ! b>rel4 ,to :at height w wat] rise 9 a tube to fill a vacuum8 ,! wat] w rise to ! height ( ?irty-f\r feet4 ,to :at useful purpose is ?is appli$8 ,x is appli$ to mak+ pumps4 ,( :at mat]ial are pumps made8 ,ei!r ( wood1 or ( metal1 su* z lead or iron4 ,:at is necess>y 9 reg>d to ! tube or pump-tree8 ,x mu/ always be air-tight4 ,:y mu/ ! tube or pump-tree be air-tight8 ,s t a vacuum may be produc$ 9 x4 ,h[ is ?is accompli%$8 ,by means ( two valves 9 ! pump-tree4 ,:at is a valve l8 ,a valve is l ! lid on a tea-kettle1 or ! cov] on an ink/&2 & x is kept 9 its place by a h+e on "o side4 ,:]e is "o valve plac$8 ,"o valve is plac$ 9 ! l[] "p ( ! pump-tube4 ,h[ ne> ! wat] mu/ ?is valve be8 ,x mu/ be )9 ?irty-f\r feet ( ! wat]4 ,:y mu/ ! l[] valve be )9 ?irty-f\r feet ( ! wat] 9 ! well8 ,because ! air c =ce wat] up a tube only to ! height ( ?irty-f\r feet4 ,does ?is valve move ab\t 9 ! pump-tube8 ,no2 x rema9s fix$ 9 "o place4 ,is ?is valve air-tight8 ,yes2 ! l[] valve or bucket 9 a pump mu/ always be air-tight4 ,:]e is ! upp] valve8 ,x is fa/5$ on ! end ( a rod1 :i* is atta*$ to ! pump-h&le4 ,does ?is valve rema9 fix$ 9 "o place8 ,no2 x moves up & d[n :5 ! pump-h&le is mov$4 ,is ! upp] valve air-tight8 ,no2 ! upp] valve is n air-tight4 ,illu/ration3 ,fig4 #af4 ,illu/ration3 ,fig4 #ag4 ,illu/ration3 ,fig4 #ah4 ,expla9 ! work+ ( a pump4 ,:5 ! pump-h&le is l[]$1 ! wat]1 above ! valve or bucket atta*$ to ! end ( ! rod1 is rais$ s t x runs out at ! sp\t2 & ! vacuum1 ?us produc$ by rais+ ! wat]1 is fill$ by ! wat] 9 ! well1 :i* is =c$ up ! pump-tube by ! pressure ( ! air4 ,:5 ! pump is at re/1 ! l[] valve1 :i* is air-tight1 prev5ts ! wat] f s9k+ back into ! well1 s t ! pump-tube is always full ( wat]1 :e!r we are pump+ or n4 ,:at does ,fig4 #af repres5t8 ,x repres5ts a pump1 :5 x is n work+4 ,h[ are ! valves8 ,! valves are bo? clos$4 ,:at keeps ! wat] above ! l[] valve8 ,! l[] valve is air-tight1 &1 !re=e1 wat]-tight1 s t x keeps ! wat] above x4 ,:at keeps ! wat] 9 ! tube bel[ ! l[] valve8 ,! pressure ( ! air on ! wat] 9 ! well1 =ces x up ! tube to ! l[] valve4 ,:at does ,fig4 #ag repres5t8 ,x repres5ts a pump1 :5 ! h&le is be+ rais$4 ,h[ is ! l[] valve8 ,! l[] valve is clos$4 ,:y is ! l[] valve clos$8 ,s z to prev5t ! wat] f be+ =c$ back aga9 into ! well4 ,h[ is ! upp] valve8 ,! upp] valve is op54 ,:y is ! upp] valve op58 ,s t ! wat] may pass up ?r\gh ! valve1 :ile ! valve is desc5d+4 ,:at does ,fig4 #ah repres5t8 ,x repres5ts a pump :5 ! h&le is be+ l[]$4 ,h[ is ! upp] valve8 ,! upp] valve is clos$4 ,:y is ! upp] valve clos$8 ,s z to lift up ! wat] :i* is above x4 ,:at becomes ( ! wat] :i* is lift$ up8 ,x runs out ( ! sp\t ( ! pump4 ,z ! upp] valve is rais$ up1 :at is produc$ "u x8 ,a vacuum is produc$ "u x4 ,h[ is ?is vacuum fill$8 ,! wat] bel[ ! l[] valve is =c$ up1 s z to fill ! vacuum4 ,h[ is ! l[] valve8 ,! l[] valve is op54 ,:y is ! l[] valve op58 ,s t ! wat] may pass ?r\gh & fill ! vacuum above ! valve4 ,:]e are pumps mo/ly us$8 ,pumps are mo/ly us$ by p 9 ! c\ntry1 = ! purpose ( obta9+ wat] f ! wells :i* h be5 sunk 9 ! e>?4 ,:5 does smoke asc5d ?r\gh ! air8 ,:5 smoke is light] ?an ! air1 x asc5ds ?r\gh x4 ,:5 does smoke desc5d ?r\gh ! air8 ,:5 smoke is heavi] ?an ! air1 x desc5ds ?r\gh x4 ,:y does a cork rise to ! surface ( ! wat]8 ,because ! cork is light] ?an ! same bulk ( wat]2 h5ce1 x asc5ds to ! surface4 ,:y does heat$ air asc5d8 ,because x is light] ?an ! cold air4 ,if a fea!r be put 9 ! heat$ air1 w x be c>ri$ up ) ! air8 ,! fea!r w be c>ri$ up ) ! air4 ,if w>m air be conf9$ 9 a bag1 w x rise up & c>ry ! bag ) x8 ,x w rise up & c>ry ! bag ) x4 ,:at might ?is bag be call$8 ,x might be call$ a balloon4 ,:at is a balloon8 ,x is a bag fill$ ) gas1 & us$ = sail+ 9 ! air4 ,illu/ration3 ,fig4 #ai4 ,:at is plac$ ov] ?is bag8 ,a network ( ropes is plac$ ov] x1 & !y are s arrang$ z to ext5d b5ea? ! bag1 z is repres5t$ 9 ,fig4 #ai4 ,:at is fa/5$ to ^! ropes8 ,a c> or basket is fa/5$ to ^! ropes4 ,:at is ! c> or basket =8 ,x is to c>ry up ^? :o wi% to asc5d ) ! balloon4 ,h[ l>ge are balloons usually made8 ,!y are f tw5ty to ?irty feet 9 diamet]4 ,) :at are balloons fill$8 ,balloons are fill$ ) a gas light] ?an air4 ,:at gas is (t5 us$ = fill+ balloons8 ,! coal gas1 su* z is us$ to light our cities at night4 ,:at light] k9d ( gas is sometimes us$8 ,hydrog5 gas is sometimes us$4 ,is hydrog5 gas mu* light] ?an ! air8 ,x is s mu* light] ?an ! air1 t fifte5 cubic feet ( hydrog5 gas weigh no m ?an "o cubic foot ( air4 ,h[ mu* less w a balloon ?irty feet 9 diamet] weigh1 :5 fill$ ) hydrog5 gas1 ?an :5 fill$ ) air8 ,x w weigh ab\t t5 ?\s& p\nds less4 ,h[ mu* less1 :5 fill$ ) coal gas ?an :5 fill$ ) air8 ,ab\t two ?\s& p\nds less4 ,h[ mu* =ce !n is necess>y to hold ! balloon fill$ ) coal gas to ! e>?8 ,a =ce ( two ?\s& p\nds1 because ! balloon is two ?\s& p\nds light] ?an ! same bulk ( air4 ,if a weight ( only "o ?\s& p\nds 7 fa/5$ to ! balloon1 :at w\ld result8 ,! balloon w\ld rise 9 ! air & c>ry ! weight ( "o ?\s& p\nds ) x4 ,h[ high w ! balloon asc5d8 ,x w asc5d until ! air displac$ is ( ! same weight z ! balloon4 ,:at w !n become ( ! balloon8 ,x w be c>ri$ ab\t 9 ! curr5ts ( air4 ,) :at is ! c> atta*$ to ! balloon load$8 ,x is usually load$ ) bags ( s&1 :i* s]ve z a weight to keep x f ris+ too high4 ,:5 ^? 9 ! c> wi% to g high]1 :at d !y d8 ,!y ?r[ ! s& out1 s z to light5 ! c>2 !n x w rise high]4 ,:5 !y wi% to desc5d1 :at d !y d8 ,!y op5 a valve at ! top ( ! balloon1 :i* p]mits "s ( ! gas to escape2 !n x w s9k t[>ds ! e>?4 ,h[ is ! valve at ! top ( ! balloon op5$ & clos$8 ,x is op5$ & clos$ by means ( small ropes1 rea*+ f ! valve to ! c> b5ea?4 ,c ! balloon be made to g 9 any "o direction8 ,no2 x is c>ri$ ab\t by ! curr5ts ( air1 & ^? 9 ! c> _c control its c\rse2 !re=e1 x has nev] be5 ( mu* use to man4 ,w9ds4 ,:at is w9d8 ,w9d is air mov+ f "o place to ano!r4 ,does ! air move 9 e direction8 ,x does move 9 e direction1 upw>d1 d[nw>d1 & to e side4 ,:5 ! w9d bl[s f ! nor? t[>ds ! s\?1 :at is x call$8 ,x is call$ a nor? w9d4 ,:at is x call$1 :5 x bl[s f o!r directions8 ,:5 x bl[s f ! ea/1 x is call$ an ea/ w9d2 f ! s\?1 a s\? w9d2 & f ! we/1 a we/ w9d4 ,:at causes ! air to move f place to place8 ,heat causes ! air to move f place to place4 ,:5 air is heat$1 :at *ange takes place8 ,! heat$ air asc5ds1 & cold] air moves 9 to fill its place2 ?us caus+ ! w9d to bl[4 ,:at illu/ration h we ( ?is8 ,:5 a c&le is held 9 ! op5 door ( a heat$ room1 its flame is bl[n outw>ds if plac$ at ! top ( ! door1 & inw>ds if plac$ at ! bottom ( ! door2 ?us %[+ two curr5ts ( air4 ,:y is ?is8 ,! heat$ air escapes f ! top ( ! room1 s z to asc5d high]1 :ile ! cold] air comes 9 at ! bottom1 to fill its place4 ,:y does ! w9d bl[ t[>ds a fire 9 ! op5 air8 ,because ! air ne> ! fire becomes heat$1 & asc5ds rapidly1 s t ! air ru%es 9 f e direction to fill its place4 ,:at does ! e>? d ) ! heat x receives f ! sun8 ,! e>? gives (f its heat to ! air ne>e/ to x4 ,:at becomes ( ?is heat$ air8 ,?is heat$ air asc5ds1 & cold] air comes to take its place2 ?us produc+ w9ds4 ,are all p>ts ( ! e>? heat$ alike by ! sun8 ,no2 !y are n all heat$ alike4 ,h[ does ?is unequal heat+ affect ! air8 ,x causes curr5ts 9 ! air all ov] ! _w4 ,does wat] give (f heat z rapidly z ! e>? does8 ,no2 wat] is a poor] radiator ( heat ?an ! e>? is4 ,on :i* w ! air be ! cool] :5 ! sun %9es1 on ! e>?1 or on ! wat]8 ,x w be cool] on ! wat] ?an on ! e>?4 ,:y does a sea-breeze feel cool 9 ! daytime8 ,because ! air ov] ! wat]1 9 ! daytime1 is less heat$ ?an ! air ov] ! l&2 h5ce1 ! sea-breeze feels cool4 ,:y does ! e>? become cold] ?an ! wat] at night8 ,because ! e>? gives (f its heat m rapidly ?an ! wat]1 & z x receives no heat f ! sun at night1 x soon becomes cold] ?an ! wat]4 ,:y does a l&-breeze feel cool at night8 ,because ! air ov] ! l& at night is less heat$ ?an ! air ov] ! wat]2 h5ce1 ! l&-breeze feels cool4 ,h[ rapidly does ! w9d move8 ,a g5tle breeze goes f\r or five miles 9 an h\r2 a high w9d goes f tw5ty to fifty miles 9 an h\r1 & a hurricane goes f sixty to "o hundr$ miles 9 an h\r4 ,( :at use is ! w9d8 ,! w9d c>ries away ! impure air & injuri\s gases f cities & o!r places1 s t !y are ! m heal?y2 x dries up ! wat] on ! surface ( ! e>?1 & ?us promotes vegetation2 x sweeps ! cl\ds fill$ ) moi/ure f ! lakes & ! oceans1 ov] e "p ( ! _w1 s t ! wat] 9 !m may fall 9 refre%+ %[]s1 to fill ! spr+s1 to purify ! air1 & 9 _m o!r ways to make ! e>? a fitt+ place ( abode = man4 ,b ^! are only a few ( ! _m bless+s t an all-wise ,creator has giv5 u2 &1 = !m all1 we %\ld ev] rememb] to (f] up to ,him ! homage ( a grateful he>t4 ,illu/ration3 ,paddle:eel /eamboat4 ,illu/ration3 ,decoration4 ,,*apt] ,v4 ,wat]4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:]e d we f9d wat]8 ,we f9d wat] almo/ ev]y:]e2 above ! e>?1 on ! e>?1 & b5ea? ! e>?'s surface4 ,:]e d we f9d wat] above ! e>?8 ,we f9d x 9 ! air1 9 ! =m ( vapor4 ,:]e d we f9d wat] on ! e>?8 ,we f9d x 9 spr+s1 9 /reams ( wat]1 & 9 lakes & oceans4 ,:]e else is wat] on ! e>?8 ,x is 9 ! sap ( plants1 ! juice ( fruits1 & ! blood ( animals4 ,:]e d we f9d wat] b5ea? ! e>?'s surface8 ,we f9d x 9 /reams runn+ 9 e direction4 ,has wat] any influ5ce on climate8 ,yes2 wat] causes _m *anges 9 climate4 ,:at *anges does wat] produce 9 climate8 ,x makes spr+ & summ] cool]1 & autumn & w9t] w>m]4 ,h[ does wat] make ! ,spr+ ( ! ye> cool]8 ,! ice & sn[ :ile melt+1 take up a l>ge am\nt ( heat1 :i* passes into ! wat] z lat5t heat4 ,:]e does ! melt+ ice & sn[ obta9 ?is heat8 ,!y obta9 x f ! air1 & f objects ne> ! surface ( ! e>?4 ,:at advantage is d]iv$ f ?is8 ,! t5d] buds & blossoms are kept back 9 ! spr+ until ! ice & ! sn[ are melt$1 & ! e>? becomes w>m$1 s t !y are seldom injur$ by ! cold4 ,h[ does wat] make ,summ] cool]8 ,by ! /reams1 lakes1 & oceans1 :i* absorb heat f ! sun2 &1 z ! wat] is a poor radiator1 b little ( ?is heat is giv5 (f to ! air4 ,:at effect does ?is heat produce ^u ! wat]8 ,! temp]ature ( ! wat] is gradually increas$ by x dur+ ! hot wea!r ( summ]4 ,h[ is ?is useful8 ,x gives heat to ! plants 9 ! wat]1 s t !y may gr[2 & x r\ses into active life1 ! fi% & o!r brea?+ ?+s1 f ! torpid /ate 9 :i* !y are dur+ w9t]4 ,does wat] /ore away a l>ge am\nt ( heat8 ,x does2 & ?us ! summ] is made mu* cool]4 ,h[ does wat] make ,autumn w>m]8 ,9 ! autumn ! heat 9 ! wat] is giv5 (f1 s t ! air is kept w>m] ?an x w\ld o!rwise be4 ,h[ does ?is affect autumn wea!r8 ,x makes t season ( ! ye> mild & pleasant4 ,:at advantage is d]iv$ f ?is8 ,x gives ! late fruits & se$s a *ance to rip52 & x af=ds "t = ! sap ( plants to return to ! roots1 & to become prep>$ = ! fro/s ( w9t]4 ,h[ does wat] make ,w9t] w>m]8 ,by be+ *ang$ into ice & sn[4 ,:5 wat] is *ang$ into ice or sn[1 :at takes place8 ,! lat5t heat 9 ! wat] is giv5 (f1 & ?us ! w9t] air is made w>m]4 ,c wat] be compress$ into a small] bulk8 ,yes2 x c be compress$1 b n s mu* z air4 ,:at is said ( wat] t is compress$8 ,its p>ticles are press$ clos] toge!r1 & x is said to be m d5se4 ,:y is ! wat] at ! bottom ( a pond m d5se ?an t at ! surface8 ,because ! wat] at ! bottom ( ! pond has to be> ! weight ( all ! wat] above x4 ,is ! weight ( ! wat] v great8 ,! weight ( ! wat] is v great4 ,:at is its weight at ! dep? ( "o hundr$ feet8 ,at ! dep? ( "o hundr$ feet1 x presses 9 e direction1 ) a =ce ( =ty-?ree p\nds on e squ>e in* ( surface4 ,:at is its weight 9 ! ocean at ! dep? ( "o mile8 ,at ! dep? ( "o mile x presses 9 e direction1 ) a =ce ( two ?\s& ?ree hundr$ p\nds on ea* squ>e in* ( surface4 ,:5 "o op5+ is made ne> ! top1 & ano!r ne> ! bottom ( a vessel full ( wat]1 f :i* w ! wat] fl[ ) ! mo/ =ce8 ,f ! op5+ ne> ! bottom ( ! vessel4 ,:y is ?is8 ,because !re is m weight ( wat] to press x out f ! op5+ ne> ! bottom4 ,:5 wat] is p\r$ into a vessel1 :at becomes ( x8 ,x spreads out s t its surface is level4 ,:5 diff]5t vessels are connect$ toge!r1 :at does ! wat] d8 ,x falls to ! same level 9 all ( !m4 ,h[ high w ! tea /& 9 ! sp\t ( a tea-pot8 ,j z high z ! tea is 9 ! tea-pot4 ,illu/ration3 ,fig4 #bj4 ,w ! tea 9 ! sp\t balance t 9 ! tea-pot8 ,! tea 9 ! sp\t w balance t 9 ! tea-pot1 z is %[n 9 ,fig4 #bj4 ,h[ else c x be %[n t wat] w rise to ! same level 9 diff]5t vessels8 ,by a ref]5ce to ,fig4 #ba1 ?is may be se54 ,illu/ration3 ,fig4 #ba4 ,let ^! vessels be made s z to connect ) ea* o!r by ! tube at ! bottom2 !n1 :5 wat] is p\r$ into "o ( !m1 x w rise up 9 ea* ( ! o!rs1 s z to be ! same height 9 all4 ,:]e is ?is pr9ciple us$ to b5efit mank9d8 ,x is us$ 9 supply+ ! inhabitants ( cities ) wat]4 ,:at mu/ be built 9 ord] to supply a city ) wat]8 ,a res]voir mu/ be built4 ,:at is a res]voir8 ,x is a l>ge bas9 made s z to hold wat]4 ,h[ high is ! wat] 9 ! bas98 ,x is usually z high z ! tops ( ! h\ses 9 ! city4 ,h[ is ! wat] rais$ into ! bas98 ,x is rais$ into ! bas9 by means ( pumps4 ,h[ is ! wat] convey$ f ! bas9 to ! h\ses 9 ! city8 ,by means ( pipes laid "u ! surface ( ! e>?1 & ext5d+ to all p>ts ( ! city4 ,h[ high w ! wat] rise 9 ^! pipes8 ,ne>ly z high z x is 9 ! bas94 ,if an op5+ be made 9 a pipe1 h[ high w ! wat] be =c$ up8 ,ne>ly z high z ! wat] 9 ! bas94 ,:at is ! wat] fl[+ f su* an op5+ call$8 ,x is call$ a f\nta94 ,:at makes ! wat] %oot up 9 a f\nta98 ,! pressure ( ! wat] 9 ! bas9 =ces x to %oot up 9 ! f\nta94 ,to :at does wat] always t5d8 ,wat] always t5ds to fall to a level4 ,:at in/rum5t is con/ruct$ on ?is pr9ciple8 ,! wat]-level4 ,:at is a wat]-level8 ,x is a glass tube s ne>ly fill$ ) wat] t x conta9s only a bubble ( air4 ,?is tube is fa/5$ 9 a piece ( wood1 z %[n 9 ,fig4 #bb4 ,illu/ration3 ,fig4 #bb4 ,h[ c we tell :5 ! in/rum5t is level8 ,by ! bubble ( air1 :i* w always be at ! c5tre ( ! tube :5 x is level4 ,:at o!r liquid may be us$ to fill ! tube8 ,alcohol may be us$ to fill ! tube1 & x is !n call$ a _s-level4 ,( :at use is ! _s-level8 ,x is us$ = levell+ ! walls & wood-"w ( h\ses1 bridges1 & o!r /ructures4 ,spr+s & ,/reams4 ,:5 we dig into ! e>?1 c we always f9d wat]8 ,yes2 we c always f9d wat]4 ,:at reason may be giv5 = believ+ ?is8 ,because ?\s&s ( wells h be5 dug 9 diff]5t p>ts ( ! c\ntry1 & wat] is obta9$ f !m4 ,are ^! wells all ( ! same dep?8 ,no2 !y v>y 9 dep? f f\r or five feet to eighty or n9ety feet4 ,:at makes ! wat] h>d 9 "s wells8 ,:5 ! /ream ( wat] passes ?r\gh iron ore1 be=e rea*+ ! well1 x absorbs "s ( ! iron1 :i* makes x h>d4 ,h[ else may x become h>d8 ,by pass+ ?r\gh o!r m9]al sub/ances1 su* z lime/one & sulphur1 x w become h>d4 ,:y is ! wat] 9 "s wells mu* w>m] ?an 9 o!rs8 ,9 wells :]e ! wat] is w>m1 ! /reams fl[+ into !m are ne> ! surface ( ! e>?1 & are heat$ by ! sun2 b 9 ! wells ( cold wat]1 ! /reams are mu* deep] 9 ! e>?4 ,:5 ^! /reams fl[ out at ! surface ( ! e>?1 :at are !y call$8 ,!y are call$ spr+s4 ,:]e are spr+s f\nd8 ,!y are mo/ly f\nd on hill-sides1 or 9 valleys2 b !y are sometimes f\nd on ! top ( ! hills4 ,:y is ! wat] 9 "s spr+s w>m] ?an 9 o!rs8 ,9 spr+s :]e ! wat] is w>m1 ! /reams fl[+ into !m are s ne> ! surface ( ! e>? z to be w>m$ by ! sun1 :ile 9 spr+s :]e ! wat] is cold]1 ! /reams are mu* deep] 9 ! e>?4 ,:at becomes ( ! wat] 9 ! spr+s8 ,x runs away d[n ! valleys1 =m+ brooks & creeks4 ,:5 ^! brooks & creeks fl[ into o!r brooks & creeks1 :at d !y =m8 ,!y =m lakes & riv]s4 ,into :at d ! riv]s fl[8 ,! riv]s fl[ into ! ocean4 ,h[ are waves produc$8 ,waves are produc$ by ! w9ds bl[+ aga9/ ! surface ( ! wat]4 ,:at does a light w9d produce8 ,a light w9d produces only ripples on ! surface ( ! wat]4 ,:at does a /rong] w9d produce8 ,a /rong] w9d produces waves 9 ! wat]4 ,:y is ! wat] ( ! ocean & ! l>g] lakes seldom at re/8 ,because ! w9d t\*+ ! wat] seldom ceases to bl[4 ,to :at dep? does ! w9d di/urb ! wat] ( ! ocean8 ,w9d seldom di/urbs ! ocean to a great] dep? ?an ?irty feet bel[ its surface4 ,fogs & ,cl\ds4 ,:at is always tak+ place f ! surface ( ! wat] 9 ! riv]s1 lakes1 & oceans8 ,! wat] is always pass+ (f 9 ! =m ( vapor4 ,:]e does ?is vapor g8 ,x goes into ! air s t ! air becomes fill$ ) moi/ure4 ,:at k9d ( air w hold ! mo/ vapor8 ,w>m air w hold ! mo/ vapor4 ,:5 w>m air becomes cold]1 :at is done ) ! vapor8 ,! vapor is cond5s$ into small p>ticles ( wat]4 ,:5 ?is takes place ne> ! e>?1 :at does x produce8 ,x produces a fog4 ,:]e d fogs mo/ly occur8 ,fogs mo/ly occur ov] l[ gr\nds & along ! c\rse ( /reams4 ,:5 ! vapor is cond5s$ high] up 9 ! air1 :at does x produce8 ,x produces a cl\d4 ,:at is a cl\d8 ,a cl\d is only a fog1 high] up 9 ! air4 ,d fogs ev] asc5d 9 ! air8 ,yes2 !y (t5 asc5d1 & ?us produce cl\ds4 ,:at causes ! vapor ( ! air to be cond5s$ into cl\ds8 ,cold causes x to be cond5s$ into cl\ds4 ,does ! air gr[ cold] z we asc5d8 ,yes2 ! high] we asc5d1 ! cold] we f9d ! atmosph]e4 ,:at becomes ( ! vapor 9 ! air1 z x asc5ds f ! e>?8 ,! vapor is cond5s$ into cl\ds 9 ! upp] regions ( ! air4 ,:y d we mo/ly see cl\ds at ! top ( a m\nta98 ,because ! vapor 9 ! air is cond5s$ into cl\ds by ! cold at ! top ( ! m\nta94 ,:5 is a cl\d =m$ 9 ! air8 ,:5 a w>m1 damp w9d meets ) a cold w9d1 its vapor is cond5s$ & a cl\d is =m$4 ,are cl\ds (t5 =m$ 9 ?is way8 ,yes2 cl\ds are (t5 quickly =m$ 9 ?is way4 ,:5 ! cl\d passes into a w>m] curr5t ( air1 :at becomes ( x8 ,x is *ang$ back into vapor1 s t x _c be se54 ,h[ !n c a cl\d 9 ! sky disappe> v quickly8 ,by pass+ into a w>m] curr5t ( air ! cl\d is *ang$ into a vapor1 & may ?us quickly disappe>4 ,are cl\ds ( diff]5t heights8 ,yes2 "s cl\ds t\* ! e>?1 :ile o!r cl\ds are high up 9 ! air4 ,:y are cl\ds high] on a f9e day8 ,because !re is n s mu* moi/ure 9 ! air1 &1 !re=e1 x rises high] be=e its vapor is cond5s$ into cl\ds4 ,:y are cl\ds l[] on a ra9y day8 ,because !re is s mu* moi/ure 9 ! air1 t x is cond5s$ into cl\ds ne> ! e>?4 ,are ! cl\ds high dur+ a ?und]-/orm8 ,no2 dur+ a ?und]-/orm ! cl\ds are seldom m ?an "o-?ird ( a mile high1 & v (t5 are mu* ne>] ! surface ( ! e>?4 ,is !re any diff]5ce 9 ! ?ickness ( ! cl\ds8 ,yes2 "s are only a few in*es ?ick1 :ile o!rs are a mile or m 9 ?ickness4 ,:5 ! sun is ab\t to rise1 :i* ( ! sev5 colors ( light is ! fir/ to appe>8 ,! r$ color appe>s fir/4 ,:5 ! sun sets1 :i* ( ! sev5 colors is ! la/ to fade away8 ,! r$ color is ! la/ to fade away4 ,:y are ! cl\ds r$ j be=e sunrise8 ,because !y are t+$ by ! r$ ray ( light1 be=e ! o!r rays appe>4 ,:y are ! cl\ds r$ aft] sunset8 ,because !y are t+$ by ! r$ ray ( light1 aft] ! o!r rays h fad$ away4 ,dew4 ,:at is dew8 ,dew is ! moi/ure t collects on plants & o!r objects1 dur+ ! night4 ,:at causes dew ^u any object8 ,! air 9 contact ) t object has its vapor cond5s$1 s t ! wat] is deposit$ on x 9 ! =m ( dew4 ,does ! same quantity ( dew collect ^u all objects8 ,no2 x collects mu* m ^u "s objects ?an ^u o!rs4 ,^u :at objects does x collect ! mo/8 ,^u ^? :i* radiate or give (f heat ! be/4 ,:y d objects t are good radiators1 collect ! mo/ dew8 ,because !y give (f _! heat rapidly aft] sunset1 & be=e morn+1 become s cold t !y cond5se ! vapor 9 ! air t\*+ !m1 & cause ! dew to be deposit$ on _! surfaces4 ,:at objects are ! be/ radiators ( heat8 ,grass1 wood1 ! leaves ( plants1 &1 9 fact1 all ?+s ( a vegetable nature4 ,:at objects !n collect ! mo/ dew8 ,plants collect ! mo/ dew4 ,( :at use is ! dew to plants8 ,x supplies !m ) moi/ure1 & answ]s 9 ! place ( ra94 ,:5 d we h ! heavie/ dew8 ,:5 ! air is /ill & ! sky is free f cl\ds4 ,:y does w9d prev5t ! deposit ( dew8 ,because ! air 9 contact ) ! grass & o!r objects1 is remov$ s quickly t x does n get cool en\gh to deposit dew4 ,:y are dews heavie/ :5 ! air is /ill8 ,because ! air rema9s 9 contact ) ! grass & o!r objects1 until x is cool en\gh to deposit ! dew4 ,:y is !re b little dew on a cl\dy night8 ,because ! cl\ds prev5t radiation ( heat f ! e>?2 h5ce1 ! e>? & ! objects ne> x1 rema9 too w>m to cause any dew4 ,:y is !re a heavy dew on a cle> night8 ,because !re is no?+ !n to prev5t free radiation ( heat f ! e>?2 h5ce1 x soon cools s z to cause a heavy dew4 ,h[ may dew be prev5t$ f =m+ on any object8 ,by plac+ a cov] ov] t object4 ,h[ does a cov] prev5t ! =mation ( dew8 ,x prev5ts ! object t is cov]$ f giv+ (f its heat1 s t x does n get cool en\gh to cause a deposit ( dew4 ,:y is !re b little dew "u trees8 ,because trees prev5t ! free radiation ( heat f ! objects b5ea? !m2 h5ce1 b little dew is =m$ "u trees4 ,:y d /one walls sweat8 ,because ! walls cool ! air 9 contact ) !m1 s t its vapor is cond5s$ into wat]1 & deposit$ on ! walls4 ,:y does ! sweat+ ( /ones indicate ra98 ,because x %[s t ! air conta9s a l>ge am\nt ( moi/ure4 ,:5 is a vessel ( wat] said to sweat8 ,:5 drops ( wat] collect on ! outside ( ! vessel1 x is said to sweat4 ,:y does a pit*] ( cold wat] sweat8 ,because ! vapor 9 ! air 9 contact ) ! cold pit*] is cond5s$ into moi/ure1 & deposit$ on ! pit*]4 ,:y does ! pit*] sweat mo/ be=e a ra98 ,because ! air !n conta9s a l>ge quantity ( moi/ure4 ,:y w n ! pit*] sweat 9 f9e wea!r8 ,because ! air conta9s only a small quantity ( moi/ure 9 f9e wea!r4 ,:y does moi/ure sometimes collect on a glass w9d[ 9 a w>m room8 ,because ! glass cools ! air1 & causes its moi/ure to collect 9 small drops on ! glass4 ,:at makes ! glass cold en\gh to cond5se ! vapor 9 ! air8 ,! cold air1 outside ( ! room1 9 contact ) ! glass4 ,:]e does ! moi/ure 9 ! air ( ! w>m room come f8 ,x comes f ! brea? ( p]sons1 & f ! /eam ( ! tea-kettle4 ,:5 ! brea? is bl[n on a cold object1 l a piece ( glass or metal1 :at is ! result8 ,! moi/ure 9 ! brea? is cond5s$ by ! cold object1 & is collect$ 9 small drops ( wat] on its surface4 ,fro/4 ,:5 ! temp]ature ( ! air is r$uc$ bel[ ?irty-two degrees1 :at becomes ( ! moi/ure collect$ on plants & o!r ?+s8 ,! moi/ure is froz54 ,:at is ?is froz5 moi/ure call$8 ,x is call$ fro/4 ,:at !n is fro/8 ,fro/ is ! froz5 moi/ure on ! walls & w9d[ panes1 & ! froz5 dew on plants & o!r objects4 ,on :at objects d we f9d ! mo/ fro/8 ,! mo/ fro/ is f\nd on objects hav+ ! mo/ dew4 ,:at is a heavy dew :5 froz5 call$8 ,x is call$ a ho>-fro/4 ,:5 d we h a ho>-fro/8 ,we h heavy fro/s :5 ! air is full ( moi/ure4 ,:y does a heavy fro/ indicate ra9 or sn[8 ,because x %[s t ! air conta9s mu* moi/ure4 ,are heavy fro/s usually foll[$ by ra9 or sn[8 ,yes2 a heavy fro/1 on two successive morn+s1 is mo/ly foll[$ by ra9 or sn[ )9 a few h\rs4 ,ra91 ,sn[1 & ,hail4 ,:at is a mi/8 ,a mi/ is v small drops ( wat] fall+ ?r\gh ! air4 ,:5 ^! drops are l>g]1 :at is x call$8 ,x is call$ ra94 ,:at causes ra98 ,ra9 is caus$ by ! sudd5 cool+ ( ! air above ! e>?4 ,h[ does cool+ ! air cause ra98 ,! cold cond5ses ! vapor 9 ! air1 s t its moi/ure is =c$ out 9 drops1 :i* fall to ! e>?4 ,:at becomes ( ! ra9 fall+ ^u ! e>?8 ,a "p ( x rema9s on ! surface ( ! e>?1 & is ei!r absorb$ aga9 by ! air1 or is c>ri$ away to ! ocean by ! creeks & riv]s4 ,:at becomes ( ! rema9+ "p8 ,x s9ks into ! e>?1 to furni% moi/ure to ! roots ( plants1 & to supply ! /reams b5ea? ! e>?'s surface ) wat]4 ,h[ does ra9 purify ! air8 ,by wa%+ away _m ?+s t w\ld1 if left1 decay & make ! air impure & unheal?y4 ,:5 ! air is cool$ bel[ ?irty-two degrees1 :at becomes ( ! moi/ure 9 x8 ,! moi/ure 9 x is froz54 ,:at is ?is froz5 moi/ure 9 ! air call$8 ,x is call$ sn[4 ,:at are ! p>ticles ( sn[ call$8 ,!y are call$ sn[-flakes4 ,are ^! sn[-flakes all alike8 ,no2 !y v>y v mu* 9 size & %ape4 ,:at does ,fig4 #bc repres5t8 ,x repres5ts a few ( ! v>i\s & beautiful =ms ( ! sn[-flake or sn[-cry/als4 ,illu/ration3 ,fig4 #bc4 ,at :at temp]ature ( ! air does sn[ usually fall8 ,at a temp]ature ( ab\t ?irty-two degrees4 ,is !re any reason = ! rem>k t x is 8too cold to sn[08 ,yes2 = x seldom sn[s :5 ! temp]ature ( ! air is mu* bel[ ?irty-two degrees4 ,( :at use is sn[8 ,! sn[ is a w>m cov]+ = ! e>?4 ,:y is sn[ a w>m cov]+ = ! e>?8 ,because ! air 9 ! sn[ makes x a poor conductor ( heat1 s t x prev5ts ! w>m? ( ! e>? f pass+ (f into ! air4 ,sn[ is1 !re=e1 a protection to ! plants1 & prev5ts _! be+ froz5 by ! cold wea!r ( w9t]4 ,:at is hail8 ,drops ( ra91 :5 froz51 are call$ hail4 ,h[ is hail =m$8 ,! ra9-drops are froz5 z !y fall ?r\gh ! air2 h5ce1 ! hail-/ones ( w9t] are no l>g] ?an ! ra9-drops4 ,:5 h we dew8 ,:5 ! air 9 contact ) ! e>? or ! plants is cool$1 its vapor is cond5s$ into dew4 ,:5 h we fro/8 ,:5 ! air 9 contact ) ! e>? or ! plants is cool$ bel[ ?irty-two degrees1 its vapor is cond5s$ into dew1 & ! dew is froz5 into fro/4 ,:5 h we fog8 ,:5 ! air ne> ! e>? is slightly cool$1 its vapor is cond5s$ into fog4 ,:5 h we cl\ds8 ,:5 ! air high] above ! e>? is slightly cool$1 its vapor is cond5s$ into cl\ds4 ,:5 h we mi/8 ,:5 ! air is a little m cool$1 its vapor is cond5s$ & mi/ falls4 ,:5 h we ra98 ,:5 ! air is /ill m cool$1 its vapor is cond5s$ & ra9 falls4 ,:5 h we sn[8 ,:5 ! air is cool$ bel[ ?irty-two degrees1 its vapor is cond5s$ & froz5 into sn[4 ,:5 h we hail8 ,:5 ! ra9-drops1 :ile fall+1 pass ?r\gh a curr5t ( air cold en\gh to freeze !m1 hail is produc$4 ,ice4 ,:at is ice8 ,ice is froz5 wat]4 ,:5 does wat] freeze8 ,wat] freezes :5 its temp]ature is r$uc$ to ?irty-two degrees4 ,is wat] increas$ 9 bulk by freez+8 ,wat] is increas$ 9 bulk by freez+4 ,:y d wat]-pipes (t5 bur/ 9 cold wea!r8 ,! wat] 9 !m freezes1 & z x increases 9 bulk1 ! pipes bur/4 ,:y are "s spr+s nev] froz58 ,because wat]1 mu* above ! freez+-po9t1 is always fl[+ into !m f ! e>?1 & ?us !y are kept too w>m to freeze4 ,:y are "s o!r spr+s froz58 ,because ! wat] fl[+ into !m comes f ne> ! surface ( ! e>?1 & is soon made cold en\gh to freeze4 ,does salt wat] freeze at ! same temp]ature z fre% wat]8 ,no2 fre% wat] freezes at ?irty-two degrees1 b salt wat] requires a l[] temp]ature dep5d+ ^u ! am\nt ( salt x conta9s4 ,h[ is ?is useful8 ,! surface ( ! ocean is nev] froz5 ov] except 9 v cold latitudes2 h5ce1 vessels may sail on x at all seasons ( ! ye>1 & c>ry ! products ( "o c\ntry to ano!r2 ?us add+ mu* to our com=t & our enjoym5t4 ,illu/ration3 ,horse4 ,illu/ration3 ,decoration4 ,,*apt] ,,vi4 ,s\nd4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:5 ! h&s are br\ght quickly toge!r1 :at is produc$8 ,!y produce a %ak+ or vibration 9 ! air4 ,:at is ?is vibration 9 ! air call$8 ,x is call$ a wave 9 ! air4 ,:at is ?is wave 9 ! air l8 ,x is l a wave 9 ! wat]4 ,:5 ?is wave 9 ! air rea*es ! e>1 :at does x produce8 ,x produces a s5sation :i* is call$ s\nd4 ,:5 a /one is dropp$ into ! wat]1 :at does x produce8 ,x produces waves 9 ! wat]4 ,h[ d ^! waves move8 ,!y move 9 e direction f ! /one4 ,d !y get small] ! f>!r !y g8 ,!y d get small] & small]1 until at la/ !y disappe>4 ,d ! waves ( s\nd 9 ! air act 9 ! same way z ! waves 9 ! wat]8 ,!y d act 9 ! same way4 ,:at !n becomes ( ! waves ( s\nd8 ,!y get small] & small] ! f>!r !y g1 until at la/ !re is no wave left4 ,:5 ! wave 9 ! air is l>ge1 :at k9d ( s\nd is made8 ,x makes a l\d s\nd4 ,z ! wave gets small]1 does ! s\nd gr[ fa9t]8 ,yes2 ! small] ! wave ! fa9t] ! s\nd1 until at la/ bo? ! wave & ! s\nd die away4 ,:]e mu/ we be to he> a l\d s\nd8 ,we mu/ be ne> ! place 9 :i* ! s\nd is made4 ,:at k9d ( waves w make a fa9t s\nd8 ,small waves 9 ! air make a fa9t s\nd4 ,w ^! waves ext5d z f> away z l>g] ones8 ,no2 z all waves ( s\nd decrease 9 size z !y rec$e1 ! smalle/ ones w soone/ disappe>4 ,:y w a l\d s\nd be he>d f>!r ?an a fa9t] s\nd8 ,because ! waves 9 ! air f ! l\d s\nd w ext5d f>!r away ?an ^? f ! fa9t] "o4 ,h[ are s\nds produc$8 ,s\nds are produc$ by /rik+ solid bodies toge!r4 ,h[ else may s\nd be produc$8 ,by /rik+ a solid body aga9/ a liquid1 z a /ick /ruck aga9/ ! wat]4 ,9 :at o!r way may s\nd be made8 ,s\nd may be made by caus+ a sub/ance to move rapidly ?r\gh ! air4 ,:5 a piece ( wood atta*$ to a /r+ is swung rapidly ar\nd1 :at k9d ( a noise is made8 ,x makes a humm+ noise4 ,:5 lightn+ passes ?r\gh ! air1 :at noise is made8 ,a noise :i* we call ?und]4 ,h[ c a murmur be produc$8 ,:5 s\nds1 too fa9t to be he>d sep>ately1 are unit$1 !y produce a murmur4 ,:]e may we he> a murmur8 ,we may he> a murmur f ! brook1 z its waves fl[ ov] ! pebbles1 & f ! w9d1 z x passes ?r\gh ! trees4 ,:5 a s\nd is he>d b once1 :at is x call$8 ,x is call$ a noise4 ,:5 s\nds are made at irregul> int]vals1 :at are !y call$8 ,!y are call$ noises4 ,:5 s\nds are repeat$ at regul> int]vals1 :at d !y become8 ,!y become musical s\nds4 ,^u :at d ! high & l[ s\nds 9 music dep5d8 ,!y dep5d ^u ! rapidity ) :i* ! waves are produc$ 9 ! air4 ,:5 ! waves are repeat$ rapidly1 :at s\nd is made8 ,!y make a high or acute s\nd4 ,:5 !y are repeat$ m sl[ly1 :at s\nd is made8 ,!y make a l[ or grave s\nd4 ,h[ small a numb] ( vibrations or waves 9 ! air c be he>d8 ,sixte5 vibrations 9 a second ( "t1 w produce ! grave/ s\nd t c be he>d4 ,h[ l>ge a numb] ( vibrations 9 ! air c be he>d8 ,tw5ty-f\r ?\s& vibrations 9 a second ( "t1 make ! mo/ acute s\nd t c be he>d4 ,h[ is ! human voice made8 ,x is made by means ( ! vocal *ords at ! upp] "p ( ! l>ynx4 ,:at is ! l>ynx8 ,! upp] "p ( ! w9dpipe is call$ ! l>ynx4 ,h[ d ^! *ords produce ! voice8 ,:5 ! air is =c$ out ( ! lungs1 x causes ^! *ords to vibrate1 s z to produce ! voice4 ,are ^! *ords ! same 9 all p]sons8 ,no2 !y are l>g] & co>s] 9 "s p]sons ?an 9 o!rs4 ,9 :om are !y l>g] & co>s]8 ,!y are usually l>g] & co>s] 9 m51 & !y are small] & f9] 9 wom54 ,:at k9d ( a voice is made by ! l>ge & co>se *ords8 ,!y make a r\gh1 co>se voice4 ,:at k9d ( voice is made by ! f9] *ords8 ,!y make a f9] & m delicate voice4 ,d ^! *ords vibrate s rapidly 9 man z 9 woman8 ,no2 !y d n vibrate s rapidly 9 man z 9 woman4 ,:at k9d ( voice d rapid vibrations make8 ,!y make an acute voice2 h5ce1 woman c1 :5 s++1 raise h] voice to a v high pit*4 ,:]e is ! s5sation ( s\nd produc$8 ,! s5sation ( s\nd is produc$ on ! e>4 ,d p v>y 9 _! ability to he>8 ,yes2 !y v>y v mu* 9 _! ability to he>4 ,is e p]son able to di/+ui% musical s\nds8 ,no2 "s p]sons _c tell "o musical note f ano!r1 & "s _c ev5 tell "o bird f ano!r by its notes4 ,is ! he>+ ( all animals alike8 ,no2 "s c he> m acutely ?an o!rs2 a lion has m acute he>+ ?an a man4 ,:at o!r animals h acute he>+8 ,all su* animals z h>es1 rabbits1 & de]4 ,( :at use is ! acute he>+ to ^! animals8 ,x enables !m quickly to he> ! approa* ( _! enemies1 s t !y may run away 9 "t to escape ! dang]4 ,conduction ( ,s\nd4 ,h[ does s\nd come to our e>s8 ,s\nd is c>ri$ to our e>s by ! air4 ,is ! air a conductor ( s\nd8 ,yes2 ! air is a conductor ( s\nd4 ,is !re any s\nd :]e !re is no air8 ,no2 !re is n any s\nd :]e !re is no air4 ,h[ d we "k ?is8 ,:5 a bell is rung 9 a vacuum1 no s\nd is he>d4 ,c s\nds be di/9ctly he>d :5 ! air is r>e8 ,no2 ! r>] ! air ! m poorly x conducts s\nd4 ,:at pro( h we ( ?is8 ,on ! top ( a high m\nta9 ! human voice is he>d only at a di/ance ( a few y>ds2 & a pi/ol :5 explod$ s\nds z fa9tly z ! break+ ( a /ick4 ,c s\nds be he>d bett] :5 ! air is d5se8 ,yes2 ! d5s] ! air1 ! bett] x conducts s\nd4 ,:at pro( h we ( ?is8 ,! human voice s\nds s di/9ctly 9 ! d5se air ( deep m9es1 t conv]sation may be c>ri$ on 9 a :isp]4 ,:y are s\nds he>d bett] at night ?an 9 ! day8 ,because ! air at night is cond5s$ by cold1 & becomes a bett] conductor ( s\nd2 also1 because ! nights are /ill]1 & few] s\nds take our att5tion4 ,:y is moi/ or damp air a bett] conductor ( s\nd ?an dry air8 ,because ! p>ticles ( wat] 9 ! damp air increase its p[] ( conduction4 ,:y is s\nd he>d f>!r :5 ov] ! wat]8 ,because ! damp air ov] ! wat] is a bett] conductor1 & because x conta9s few] objects to ob/ruct ! waves ( s\nd4 ,h[ f> has ! human voice be5 he>d ov] ! wat]8 ,! words 8all's well0 h be5 he>d across ! ,/rait ( ,gibralt>1 a di/ance ( t5 miles4 ,h[ f> has ! human voice be5 he>d ov] ! l&8 ,x has be5 he>d at ! di/ance ( f\r miles4 ,h[ does ! w9d affect s\nd8 ,! w9d c>ries ! s\nd ! way 9 :i* x is bl[+1 s t a noise may be he>d mu* f>!r ) ! w9d ?an aga9/ x4 ,:y does wat] conduct s\nd fa/] ?an air8 ,because ! p>ticles ( wat] are clos] toge!r ?an ! p>ticles ( air4 ,h[ c we prove t wat] is a conductor ( s\nd8 ,:5 a bell is rung "u wat]1 ! s\nd may be he>d by any p]son ^: head is b5ea? ! surface ( ! wat]4 ,does a solid sub/ance conduct s\nd m rapidly ?an air8 ,x does1 mu* m rapidly4 ,h[ c we prove ?is8 ,:5 ! e> is plac$ at "o end ( a log ( wood & ! o!r end is /ruck ) a hamm]1 two s\nds w be he>d2 fir/1 ! "o com+ ?r\gh ! log1 &1 aft]w>ds1 ! "o com+ ?r\gh ! air4 ,:at use is made ( ?is fact8 ,! tramp+ ( horses or ! rumbl+ ( c>s & wagons1 :5 at a di/ance1 may be he>d by plac+ ! e> ne> ! gr\nd4 ,d all solid sub/ances produce ! same am\nt ( s\nd :5 /ruck8 ,no2 s(t sub/ances1 su* z lead & wood1 produce b little s\nd2 :ile h>d sub/ances1 su* z copp]1 bell-metal1 & glass1 produce mu* m s\nd4 ,:at are h>d bodies1 produc+ mu* s\nd1 call$8 ,!y are call$ sonor\s bodies4 ,is a bell a v sonor\s body8 ,yes2 a bell is "o ( ! mo/ sonor\s bodies t we h4 ,:y does a bell r+ :5 /ruck8 ,because ! /roke causes ! p>ticles ( ! bell to vibrate4 ,:5 we t\* a bell :ile r++1 :y does ! s\nd /op8 ,because we /op its vibrations :5 we t\* x4 ,:y does a crack 9 a bell *eck its r++8 ,because ! crack /ops ! vibrations 9 ! metal4 ,:at o!r sub/ances r+ :5 /ruck8 ,all vessels made ( glass1 e>?1 /one1 iron1 etc41 r+ :5 /ruck4 ,h[ may we detect a crack 9 any su* vessel8 ,by /rik+ ! vessel2 if x is crack$ !re w be no r++ s\nd4 ,trumpets & ,speak+-,tubes4 ,h[ d ! waves ( s\nd move8 ,! waves ( s\nd move 9 e direction f ! place :]e ! noise is made4 ,:y d we put bo? h&s ar\nd ! m\? :5 we call to a p]son at a di/ance f u8 ,we d s to keep ! waves ( s\nd m toge!r4 ,does x make ! voice l\d]8 ,x does make ! voice l\d]4 ,:at in/rum5t has be5 made s z to op]ate 9 ! same way8 ,! speak+-trumpet1 z is %[n 9 ,fig4 #bd4 ,illu/ration3 ,fig4 #bd4 ,( :at use are speak+-trumpets8 ,!y are ( mu* use to firem5 :5 giv+ ord]s at a fire1 & to ^? on bo>d ( vessels :5 giv+ ord]s to ! sailors4 ,:y d we hold ! h& beh9d ! e> :5 we wi% to he> m di/9ctly8 ,because ! h& cat*es m ( ! waves ( s\nd1 & conducts !m to ! e>4 ,:at in/rum5t has be5 made to s]ve ! same purpose8 ,! e>-trumpet1 z is %[n 9 ,fig4 #be4 ,illu/ration3 ,fig4 #be4 ,h[ does ! e>-trumpet aid ! he>+8 ,! l>ge end ( ! trumpet collects m ( ! waves ( s\nd ?an ! e> c2 h5ce1 m waves rea* ! e>4 ,:y d su* animals z ! horse1 ! rabbit1 & ! de]1 he> bett] ?an we d8 ,because _! l>ge e>s act l e>-trumpets to collect ! waves ( s\nd1 & ?us increase _! faculty ( he>+4 ,h[ c ^! animals /ill f>!r increase _! s5se ( he>+8 ,by be+ able to turn _! e>s1 j z we d ! e>-trumpet1 9 ! direction :5ce ! s\nd comes4 ,:at are speak+-tubes8 ,!y are metal pipes ext5d+ f "o "p ( a build+ to ano!r "p4 ,( :at use are speak+-tubes8 ,!y are us$ to convey ! voice to ! m di/ant p>ts ( a build+4 ,d !y require l\d talk+8 ,no2 ev5 a :isp] has be5 he>d ?r\gh a metal pipe ov] ?ree ?\s& feet long4 ,velocity ( ,s\nd4 ,h[ fa/ d ! waves ( s\nd move ?r\gh ! air8 ,!y move at ! rate ( t5 hundr$ & n9ety feet 9 a second ( "t1 :5 ! temp]ature ( ! air is ?irty-two degrees4 ,:at effect does w>m air h on s\nd8 ,s\nd travels m rapidly 9 w>m air4 ,h[ mu* does heat increase ! velocity ( s\nd8 ,! velocity ( s\nd is increas$ "o foot 9 a second ( "t1 = e degree ( heat add$ to ! air2 s t s\nd travels elev5 hundr$ & tw5ty feet 9 a second1 :5 ! temp]ature is at sixty-two degrees1 :i* is ne>ly "o mile 9 five seconds4 ,does light travel m rapidly ?an s\nd8 ,yes2 light comes f ! moon to ! e>?1 a di/ance ( two hundr$ & =ty ?\s& miles1 :ile s\nd moves elev5 hundr$ & tw5ty feet4 ,:at famili> examples ( ?is diff]5ce may be giv58 ,a wood-*opp]'s axe is se5 to desc5d be=e we he> ! /roke1 & ! smoke f a gun is se5 be=e we he> ! report4 ,h[ c we tell ! di/ance ( ! wood-*opp] f u8 ,if we c\nt ! numb] ( seconds betwe5 ! /roke ( ! axe & ! "t :5 ! s\nd rea*es our e>1 & multiply elev5 hundr$ & tw5ty by ?is numb]1 x w give u ! di/ance 9 feet2 because s\nd travels elev5 hundr$ & tw5ty feet 9 a second4 ,h[ c we tell ! di/ance ( lightn+ f u8 ,if we c\nt ! numb] ( seconds betwe5 ! lightn+ & ! ?und]1 & divide ?is numb] by five1 x w give ! di/ance 9 miles2 because s\nd travels "o mile 9 e five seconds4 ,h[ rapidly does s\nd travel ?r\gh wat]8 ,s\nd travels ab\t f\r times z rapidly ?r\gh wat] z x does ?r\gh air4 ,h[ rapidly does s\nd travel ?r\gh a solid8 ,s\nd travels t5 times z rapidly ?r\gh wood1 & sixte5 times z rapidly ?r\gh glass1 z x does ?r\gh air4 ,does a l\d s\nd travel m rapidly ?an a fa9t "o8 ,no2 x does n4 ,h[ d we "k ?is8 ,because ! notes f a b& ( music come to u 9 ! ord] 9 :i* !y are play$1 :e!r !y are l\d or fa9t4 ,reflection ( ,s\nd4 ,:at becomes ( ! waves ( s\nd :5 !y /rike a solid sub/ance8 ,!y are ?r[n back1 z light f a look+-glass1 or a ball f a /one wall4 ,:at is ?is call$8 ,x is call$ reflection ( s\nd4 ,9 :at direction is s\nd reflect$8 ,s\nd1 l light1 is reflect$ s t ! angles ( incid5ce & reflection are always equal4 ,:5 ! reflect$ s\nd comes back to ! e>1 :at does x make8 ,x makes an e*o4 ,:5 ! s\nd comes back sev]al times1 :at does x make8 ,x makes sev]al e*oes4 ,:]e are e*oes always to be he>d8 ,e*oes may be he>d 9 ! deep caves ( ! e>?2 because ! walls ( ! caves reflect s\nds /rik+ aga9/ !m4 ,:at curi\s e*o may be m5tion$8 ,!re is an e*o 9 ,fairfax ,c\nty1 ,virg9ia1 :i* s5ds back tw5ty notes play$ on a flute4 ,does e reflection ( s\nd produce an e*o8 ,no2 x does n4 ,:y is !re no e*o f ! walls ( a small room8 ,because ! walls are too close toge!r to make an e*o4 ,h[ f> away mu/ ! reflection ( a s\nd be made1 s z to produce a p]fect e*o8 ,s\nd mu/ be made n less ?an "o hundr$ & twelve feet di/ant to produce a p]fect e*o4 ,h[ _m syllables c be he>d f an e*o "o hundr$ & twelve feet di/ant8 ,only "o syllable c be he>d4 ,h[ f> mu/ ! e*o be to he> two syllables8 ,x mu/ be twice ! "o hundr$ & twelve feet1 or two hundr$ & tw5ty-f\r feet1 to he> two syllables2 & ?ree times t di/ance to he> ?ree syllables1 & s on4 ,:y c a p]son :5 speak+1 be he>d bett] 9 a room ?an 9 ! op5 air8 ,because ! walls ( ! build+ reflect 8 voice to ! he>]s1 s t m waves ( s\nd rea* _! e>s4 ,:y are noises he>d s di/9ctly 9 an unfurni%$ dwell+8 ,because !re is !n no?+ b ! walls to ob/ruct ! waves ( s\nd2 b :5 ! dwell+ is furni%$1 ea* article ( furniture helps to ob/ruct ! s\nd & to make x less di/9ct4 ,:at may be said ( ! h>mony ( s\nds8 ,! babbl+ ( ! brook1 ! ro>+ ( ! cat>act1 ! wail+ ( ! w9d1 & ! s++ ( ! birds1 ev]y:]e %[ ! ,div9e love ( h>mony2 = :]e !re is no human e> to li/51 !y /ill s+ _! heav5ly an!ms ( praise to ,8 e> alone4 ,illu/ration3 ,horse-drawn trolley c>4 ,illu/ration3 ,decoration4 ,,*apt] ,,vii4 ,matt]4 ,illu/ration3 ,illu/rat$ ,capital ,i ,9 :at =m is all matt] f\nd8 ,9 ! =m ( a solid1 a liquid1 or a gas4 ,:at is true ( all solids8 ,all solids mu/ h l5g?1 bread?1 & ?ickness4 ,d solids v>y mu* 9 l5g?1 bread?1 & ?ickness8 ,yes2 !y v>y s mu* t we c sc>cely f9d two ?+s exactly alike 9 %ape & size4 ,c ! %ape ( any sub/ance be *ang$8 ,yes2 its %ape may be *ang$ 9 _m ways4 ,:at takes place 9 india-rubb] :5 x is /ret*$8 ,its p>ticles are drawn f>!r ap>t1 & its %ape is alt]$4 ,:5 ! =ce is remov$1 :at does ! india-rubb] d8 ,x spr+s back into its =m] %ape4 ,:at is ?is prop]ty ( ! india-rubb] call$8 ,x is call$ ,ela/icity4 ,c air be press$ into a small] bulk8 ,x c1 by means ( a weight4 ,:5 ! weight is remov$1 :at does ! air d8 ,! air goes back to its =m] bulk4 ,is air v ela/ic8 ,yes2 air is "o ( ! mo/ ela/ic sub/ances kn[n4 ,:y does a ball reb\nd :5 ?r[n aga9/ ! floor8 ,because ! sub/ance ( ! ball is press$ out ( %ape :5 x /rikes ! floor1 &1 9 its ef=t to spr+ back to its =m] %ape1 x is =c$ to reb\nd4 ,:y does ! ball reb\nd f ! floor8 ,because ! floor is firm1 & w n move f ! ball4 ,does a ball reb\nd :5 x /rikes a s(t sub/ance8 ,no2 x does n reb\nd :5 x /rikes a s(t sub/ance1 l a heap ( wool or fea!rs4 ,are solids ev] ela/ic8 ,yes2 _m solids are ela/ic4 ,"n "s articles useful f _! ela/ic prop]ties4 ,wat*-spr+s1 wagon-spr+s1 /eel p5s1 & spr+ seats are v useful4 ,:y does a wood5 b[ ?r[ an arr[ f x8 ,:5 ! =ce t b5ds ! b[ is remov$1 x spr+s back to its =m] %ape1 & 9 s do+ ?r[s ! arr[ f x4 ,c metals be b5t8 ,yes2 ne>ly all metals c be b5t4 ,:at is ?is prop]ty ( be+ b5t call$8 ,x is call$ ,flexibility4 ,d sub/ances usually spr+ back aft] be+ b5t8 ,no2 !y usually rema9 9 ! b5t =m4 ,c glass be b5t8 ,glass c be b5t only a v little )\t be+ brok54 ,:at is ?is prop]ty ( be+ easily brok5 call$8 ,x is call$ ,brittl5ess4 ,:at may be said ( brittle sub/ances8 ,brittle sub/ances are g5]ally h>d1 :ile flexible sub/ances are mu* s(t]4 ,:at metal may be made ei!r flexible or brittle8 ,/eel1 :5 heat$ & cool$ sl[ly1 becomes flexible1 b :5 cool$ quickly1 x becomes brittle4 ,= :at is brittle /eel us$8 ,x is us$ = mak+ knives1 razors1 axes1 & o!r cutt+ in/rum5ts4 ,:at may be done ) metals t are flexible8 ,!y may be hamm]$ into ?9 plates4 ,:at is ?is prop]ty 9 metals call$8 ,x is call$ ,malleability4 ,:i* is ! mo/ malleable ( all metals8 ,gold is ! mo/ malleable2 & x c be made into leaves s ?9 t ?ree hundr$ & sixty ?\s& ( !m1 :5 plac$ toge!r1 make a bulk only "o in* 9 ?ickness4 ,"n "s o!r metals t are malleable4 ,silv]1 copp]1 t91 z9c1 iron1 & lead4 ,c ! p>ticles ( a piece ( iron easily be sep>at$8 ,no2 its p>ticles _c easily be sep>at$4 ,:at is ?is prop]ty ( iron call$8 ,x is call$ ,t5acity4 ,c ! p>ticles ( a brittle sub/ance1 l glass1 easily be sep>at$8 ,yes2 its p>ticles c easily be sep>at$4 ,is !re mu* t5acity 9 brittle sub/ances8 ,no2 !re is v little t5acity 9 brittle sub/ances4 ,is !re any t5acity 9 air8 ,no2 because its p>ticles are always try+ to sep>ate f ea* o!r4 ,is !re any t5acity 9 wat]8 ,only a little1 j en\gh to hold its p>ticles toge!r 9 ! =m ( drops4 ,^u :at does ! /r5g? ( sub/ances dep5d8 ,_! /r5g? dep5ds ^u _! t5acity4 ,d ! diff]5t k9ds ( wood v>y mu* 9 /r5g?8 ,yes2 hickory & oak are mu* /rong] ?an p9e or c$>4 ,:5 is a k ( ! /r5g? ( wood necess>y8 ,x is necess>y to "k ! /r5g? ( wood us$ 9 ! con/ruction ( /ores1 bridges1 h\ses1 etc4 ,:i* is ! mo/ t5aci\s ( metals8 ,iron is ! mo/ t5aci\s ( metals4 ,h[ is ?is pr9ciple 9 iron made useful8 ,x is useful 9 ! con/ruction ( susp5sion bridges1 & 9 v _m o!r ways4 ,c iron be drawn into wire8 ,yes2 iron c be drawn into wire4 ,:at is ?is prop]ty ( be+ drawn into wire call$8 ,x is call$ ,ductility4 ,:i* are ! mo/ ductile ( metals8 ,plat9um1 silv]1 iron1 copp]1 & gold1 are ! mo/ ductile1 9 ! ord] nam$4 ,:5 is glass ductile8 ,:5 glass is melt$ x becomes ductile1 & may be drawn into v f9e ?reads4 ,if we take half ! air out ( a room1 :at w ! rema9+ half d8 ,its p>ticles w sep>ate until !y fill ! :ole room4 ,:at is said ( air :5 its p>ticles are ?us sep>at$8 ,! air is 9 a /ate ( r>ity4 ,:at is said ( x :5 ! p>ticles are press$ clos] toge!r8 ,! air is !n said to be 9 a /ate ( d5sity4 ,are ! p>ticles ( wat] clos] toge!r ?an ^? ( air8 ,yes2 !re=e wat] is d5s] ?an air4 ,^u :at does ! weight ( a sub/ance dep5d8 ,its weight dep5ds ^u its d5sity4 ,h[ mu* heavi] is /eel ?an wat]8 ,/eel is sev5 times z heavy z wat]1 & is1 !re=e1 sev5 times z d5se4 ,h[ mu* d5s] is m]cury ?an wat]8 ,m]cury is ?irte5 times z d5se z wat]1 & is1 !re=e1 ?irte5 times z heavy4 ,:y c a bird move ?r\gh ! air8 ,because ! p>ticles ( air c be sep>at$ by ! bird4 ,:y c a fi% swim ?r\gh ! wat]8 ,because ! p>ticles ( wat] c be sep>at$ by ! fi%4 ,:y c a ne$le be pass$ ?r\gh clo?8 ,because ! fibres ( ! clo? c be sep>at$ by ! ne$le4 ,:y c a nail be driv5 ?r\gh a bo>d8 ,because ! fibres ( wood c be sep>at$ by ! nail4 ,:at "n giv5 to ?is prop]ty 9 ^! sub/ances8 ,?is prop]ty is call$ ,p5etrability4 ,:at is necess>y 9 ord] to p5etrate a sub/ance8 ,we mu/ use a sub/ance h>d] ?an ! "o :i* we wi% to p5etrate4 ,:y w iron p5etrate wood8 ,because iron is h>d] ?an wood4 ,:y _c our bodies p5etrate ! wood8 ,because our bodies are s(t] ?an ! wood4 ,:y c our bodies move m easily ?r\gh air ?an ?r\gh wat]8 ,because air is m easily p5etrat$ ?an wat]4 ,:y c a nail be driv5 into a p9e bo>d m easily ?an into an oak bo>d8 ,because ! fibres ( p9e are m easily sep>at$ ?an ! fibres ( oak2 h5ce1 p9e wood is m p5etrable ?an oak wood4 ,illu/ration3 ,decoration4 ,illu/ration3 ,decoration4 ,,*apt] ,,viii4 ,attraction4 ,cohesion & ,adhesion4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:y c a cup be lift$ by tak+ hold ( ! h&le8 ,because ! p>ticles ( ! cup d n sep>ate f ea* o!r4 ,:at is ! p[] :i* holds ^! p>ticles toge!r call$8 ,x is call$ ,cohesion4 ,9 :at bodies is cohesion ! /ronge/8 ,cohesion is /ronge/ 9 solid bodies4 ,is ! cohesion alike 9 all solids8 ,no2 ! cohesion 9 iron is mu* great] ?an ! cohesion 9 wood4 ,^u :at does ! /r5g? ( a sub/ance dep5d8 ,! /r5g? ( a sub/ance dep5ds ^u ! am\nt ( cohesion among its p>ticles4 ,:at effect does heat h ^u ! cohesion ( bodies8 ,heat t5ds to de/roy ! cohesion ( bodies by sep>at+ _! p>ticles4 ,h[ does heat affect ice8 ,heat de/roys ! cohesion betwe5 ! p>ticles ( ice1 & ?us x is *ang$ into wat]4 ,h[ does heat affect wat]8 ,:5 /ill m heat is appli$1 ! cohesion 9 ! wat] is de/roy$1 & ?us x is *ang$ into /eam4 ,is !re any cohesion 9 /eam8 ,no2 !re is n any cohesion 9 /eam4 ,is !re any cohesion 9 air8 ,no2 because ! p>ticles ( air are always try+ to sep>ate f ea* o!r4 ,is !re any cohesion 9 liquids8 ,yes2 !re is "s cohesion 9 liquids1 b x is only /rong en\gh to hold !m toge!r 9 drops4 ,does ! cohesion 9 liquids v>y8 ,yes2 ! cohesion 9 m]cury is /rong] ?an x is 9 wat]2 !re=e1 a drop ( m]cury is l>g] ?an a drop ( wat]4 ,h[ is x 9 *lor(orm8 ,! cohesion 9 *lor(orm is weak] ?an x is 9 wat]2 !re=e1 a drop ( *lor(orm is small] ?an a drop ( wat]4 ,h[ is %ot made8 ,:5 lead is melt$ & p\r$ ?r\gh a sieve at ! top ( a high t[]1 ! attraction ( cohesion =ms x into r\nd drops or globules2 ^! cool1 :ile fall+1 ?us =m+ ! gra9s ( %ot4 ,h[ high mu/ a %ot-t[] be8 ,a %ot-t[] mu/ be n less ?an two hundr$ feet high1 s t ! lead may h>d5 :ile fall+4 ,:y does putty /ick to a pane ( glass8 ,because !re is an attraction betwe5 ! putty & ! glass4 ,:at is ?is attraction call$8 ,x is call$ ,adhesion4 ,^u :at does adhesion dep5d8 ,adhesion dep5ds ^u ! attraction :i* sub/ances h = ea* o!r4 ,has wat] any attraction = oil8 ,no2 !re=e1 !re is no adhesion betwe5 oil & wat]4 ,has glass any attraction = wat]8 ,yes2 !re=e1 ! wat] collects on ! glass 9 drops4 ,:at o!r examples ( adhesion may be giv58 ,pa9t adh]es to wood1 du/ to furniture1 & t9 & m]cury to ! back ( a look+-glass4 ,w y "n a few ( ! mo/ adhesive sub/ances8 ,glue1 mort>1 pa/e1 & putty4 ,( :at use is glue8 ,glue fa/5s pieces ( wood toge!r4 ,( :at use is mort>8 ,mort> fa/5s toge!r ! bricks & /ones us$ 9 ! con/ruction ( h\ses & o!r build+s4 ,( :at use is pa/e8 ,pa/e fa/5s pieces ( pap] toge!r1 & x fa/5s pap] to ! walls & ceil+s ( rooms4 ,( :at use is putty8 ,putty fa/5s ! glass to ! wood-"w ( our w9d[s4 ,capill>y ,attraction4 ,:y does a sponge suck up wat]8 ,because ! p>ticles ( ! sponge h an attraction = ! wat]4 ,:at is ?is attraction call$8 ,x is call$ ,capill>y attraction4 ,9 :at bodies d we f9d ! mo/ capill>y attraction8 ,9 ^? t are ( a por\s or spongy nature4 ,:y does a lump ( sug> or salt1 :5 p>tly dipp$ into wat]1 soon become entirely wet8 ,because sug> & salt are por\s sub/ances1 & ! wat] rises 9 !m by capill>y attraction4 ,:y does a heap ( dry s& soon become damp :5 "o edge t\*es ! wat]8 ,because ! wat] is drawn ?r\gh ! s& by capill>y attraction4 ,:y does wat] p\r$ into ! sauc] ( a fl[]-pot soon wet ! e>? 9 ! fl[]-pot8 ,because ! e>? is por\s1 & ! wat] is drawn up ?r\gh x by capill>y attraction4 ,h[ does ! oil 9 a lamp rise s z to be burn$8 ,! oil is drawn up ?r\gh ! wick by capill>y attraction4 ,:]e may examples ( capill>y attraction be notic$8 ,9 blott+-pap] :5 x takes up ! ink1 & 9 bread :5 x soaks up ! juice ( meats4 ,:at o!r examples may be giv58 ,:5 "o end ( a t[el is plac$ 9 a bas9 ( wat]1 & ! o!r end is left hang+ outside ! bas91 ! wat] w pass ?r\gh ! t[el by capill>y attraction1 until ! bas9 is entirely dry4 ,:y is wat] 9 a glass tumbl] a little elevat$ at ! edges8 ,because ! glass has a slight attraction = ! wat] ne> x1 & ?us lifts x up a little4 ,:y w wat] rise 9 a small glass tube high] ?an 9 ! surr\nd+ vessel8 ,because ! glass has an attraction = ! wat]1 & elevates x at ! edges1 z is %[n 9 ,fig4 #bf4 ,illu/ration3 ,fig4 #bf4 ,:y d salt & o!r sub/ances dissolve 9 wat]8 ,because wat] ov]comes ! =ce ( cohesion 9 ! salt1 & ?us sep>ates its p>ticles4 ,! capill>y attraction betwe5 ! salt & ! wat] is great] ?an ! cohesion betwe5 ! p>ticles ( salt2 h5ce1 ! salt is dissolv$ by ! wat]4 ,gravitation4 ,:5 a ball is ?r[n into ! air1 :y does x fall back to ! e>?8 ,because ! e>? attracts ! ball4 ,:y d ra9 & sn[ fall to ! e>?8 ,because ! e>? attracts !m4 ,:at is ?is k9d ( attraction call$8 ,x is call$ attraction ( ,gravitation4 ,does ! attraction ( gravitation exi/ 9 all ?+s8 ,yes2 e sub/ance attracts e o!r sub/ance4 ,^u :at does ! attraction ( gravitation 9 a body dep5d8 ,x dep5ds ^u ! size & weight ( t body4 ,d l>g] bodies attract ) m =ce ?an small] ones8 ,yes2 l>g] bodies d attract m ?an small] ones4 ,d heavy bodies attract ) m =ce ?an light ones8 ,yes2 heavy bodies d attract m ?an light ones1 al?\gh !y may be ( ! same size4 ,:]e are all sub/ances drawn by ! attraction ( gravitation8 ,!y are all drawn t[>ds ! c5tre ( ! e>?4 ,:y are sub/ances drawn t[>ds ! c5tre ( ! e>?8 ,because ! e>? is l>g] ?an any sub/ance on or ne> its surface4 ,9 :at direction d all objects fall ?r\gh ! air8 ,!y all fall t[>ds ! c5tre ( ! e>?4 ,:i* way !n d we call 8d[n08 ,d[n is always t[>ds ! c5tre ( ! e>?4 ,:i* way d we call 8up08 ,up is always away f ! c5tre ( ! e>?4 ,:]e mu/ all plumb l9es or p]p5dicul> l9es po9t8 ,!y mu/ all po9t ) "o end t[>ds ! c5tre ( ! e>?4 ,:5 ! e>? turns ov]1 c any sub/ance fall away f its surface8 ,no2 all ?+s are drawn to ! e>? ) s mu* =ce t !y _c fall away4 ,^u :at does ! weight ( a body dep5d8 ,! weight ( a body dep5ds ^u ! =ce ) :i* x is drawn t[>ds ! e>?4 ,:at k9d ( sub/ances are attract$ ) ! mo/ =ce8 ,^? t are ! mo/ d5se1 l ! metals2 h5ce1 !y are ! heavie/4 ,:at causes a liquid to =m into a drop at ! m\? ( a bottle8 ,! attraction ( cohesion causes ! drop to be =m$4 ,:at causes ! drop to fall to ! e>?8 ,! attraction ( gravitation causes ! drop to fall to ! e>?4 ,:5 wat] is p\r$ f a tumbl]1 :y does x run d[n ! side ( ! tumbl]8 ,because ! attraction ( cohesion draws ! wat] to ! side ( ! tumbl]1 z is %[n 9 ,fig4 #bg4 ,illu/ration3 ,fig4 #bg4 ,:y does a sp\t prev5t ! wat] f runn+ d[n ! side ( ! vessel8 ,because ! sp\t is curv$ s t its l[e/ po9t is :]e ! wat] falls f x2 h5ce1 gravitation causes ! wat] to fall directly to ! e>?1 z is %[n 9 ,fig4 #bh4 ,illu/ration3 ,fig4 #bh4 ,does ! air ob/ruct bodies :5 fall+ ?r\gh x8 ,yes2 air ob/ructs all bodies :5 fall+ ?r\gh x2 b x ob/ructs light bodies m ?an heavy ones4 ,d all bodies fall ) equal rapidity 9 a vacuum8 ,yes2 all bodies fall ) equal rapidity 9 a vacuum4 ,:at bodies fall ?r\gh ! air mo/ rapidly8 ,^? t are ! heavie/ or mo/ d5se2 because !y are ! smalle/ 9 bulk4 ,d heavy bodies increase 9 velocity z !y desc5d8 ,!y d increase rapidly 9 velocity z !y desc5d4 ,h[ f> does a heavy body l lead fall 9 "o second8 ,x falls sixte5 feet 9 "o second4 ,a fall+ body increases ?irty-two feet 9 velocity = e second ( "t x is 9 fall+4 ,dur+ ! fir/ second x falls sixte5 feet4 ,dur+ ! second second1 x falls sixte5 feet plus ?irty-two feet1 or =ty-eight feet4 ,dur+ ! ?ird second1 x falls =ty-eight feet plus ?irty-two feet1 or eighty feet1 etc4 ,a ris+ body decreases ?irty-two feet 9 velocity = e second ( "t x is 9 ris+4 ,if x be ?ree seconds 9 ris+1 its velocity w be eighty feet ! fir/ second1 =ty-eight feet ! second second1 & sixte5 feet ! ?ird second1 be+ j ! rev]se ( ! same body :5 fall+1 z is %[n 9 ,fig4 #bi4 ,illu/ration3 ,fig4 #bi4 ,h[ may ! di/ance a body falls 9 a giv5 "t be f\nd8 ,x may be f\nd by multiply+ ! numb] ( seconds x is 9 fall+1 by ! same numb]1 & ?is product by sixte5 feet4 ,?us1 :5 x is ?ree seconds 9 fall+1 multiply ?ree by ?ree1 & ?is product by sixte5 feet1 :i* gives "o hundr$ & =ty-f\r feet1 ! di/ance x falls 9 ?ree seconds4 ,:at famili> example h we ( ! =ce ( fall+ bodies8 ,we h an example 9 ! l>ge hail-/ones :i* fall to ! e>? 9 summ]-"t1 break+ ! glass 9 our w9d[s & do+ mu* injury to ! crops4 ,c5tre ( ,gravity4 ,:at is ! c5tre ( gravity 9 a body8 ,! c5tre ( gravity 9 a body1 is ! po9t on :i* ! body may be balanc$1 z is %[n 9 ,fig4 #cj4 ,illu/ration3 ,fig4 #cj4 ,:]e is ! c5tre ( gravity 9 a circle8 ,x is ! c5tre ( ! circle4 ,:]e is ! c5tre ( gravity 9 a ball8 ,x is ! c5tre ( ! ball4 ,:at influ5ce does ! e>? h on ! c5tre ( gravity8 ,! e>? draws ! c5tre ( gravity 9 a body z ne> to itself z possible4 ,:y w an egg1 :5 plac$ on ei!r end1 fall ov] on its side8 ,because ! c5tre ( gravity is ne>] ! e>? :5 ! egg is plac$ ^u its side ?an :5 ^u ei!r end1 z is %[n 9 ,fig4 #ca & ,fig4 #cb4 ,illu/ration3 ,fig4 #ca4 ,illu/ration3 ,fig4 #cb4 ,:y w a ball rema9 9 any position :5 plac$ on ! e>?8 ,because its c5tre ( gravity is always ! same di/ance f ! e>?1 :atev] may be its position4 ,:5 w a body *ange its position if left unsupport$8 ,a body w *ange its position :5ev] by s do+ its c5tre ( gravity w be l[]$4 ,:5 may a body be readily mov$ ab\t8 ,:5 its c5tre ( gravity always rema9s at ! same di/ance f ! e>? :ile be+ mov$4 ,:y is a r\nd body1 l a ball1 easily roll$ ab\t ! floor8 ,because its c5tre ( gravity rema9s at ! same di/ance f ! floor4 ,:5 is ! position ( a body difficult to *ange8 ,:5ev] ! c5tre ( gravity 9 x has to be lift$ up 9 ord] to make ! *ange1 z is %[n 9 ,fig4 #ce4 ,illu/ration3 ,fig4 #cc4 ,illu/ration3 ,fig4 #cd4 ,illu/ration3 ,fig4 #ce4 ,! c5tre ( gravity1 9 ,fig4 #cc1 may be l[]$2 h5ce1 x w *ange its position if unsupport$4 ,! c5tre ( gravity1 9 ,fig4 #cd1 c nei!r be l[]$ nor lift$ up2 h5ce1 x may be readily roll$ ab\t4 ,! c5tre ( gravity1 9 ,fig4 #ce1 mu/ be lift$ up2 h5ce1 x rema9s firm 9 its place4 ,:5 does an object /& firm8 ,x /&s firm :5 x has a broad base1 & its c5tre ( gravity is ne> ! e>?4 ,:at effect is produc$ by elevat+ ! c5tre ( gravity8 ,! high] ! c5tre ( gravity 9 any body is rais$ above ! e>?1 ! great] is its t5d5cy to fall4 ,:y is a load ( hay m easily ov]turn$ ?an a load ( iron1 :5 ^u ! same wagon8 ,because ! c5tre ( gravity 9 ! load ( hay is mu* high] ?an x is 9 ! load ( iron4 ,:y d pass5g]s on top ( a /age cause x to ov]turn m easily8 ,because _! weight on ! top raises ! c5tre ( gravity 9 ! /age1 & x is m readily ov]turn$4 ,:y is a p]son m likely to fall :5 /&+ up ?an :5 sitt+ d[n8 ,because ! c5tre ( gravity is high] 9 a p]son :5 /&+ ?an :5 sitt+4 ,:y is a boy m likely to fall :5 rais$ on /ilts8 ,because ! c5tre ( gravity 9 ! boy is f>!r f ! e>? :5 he is rais$ on /ilts4 ,:5 w a load ( hay be ov]turn$8 ,x w be ov]turn$ :5ev] ! l9e f ! c5tre ( gravity to ! e>? falls outside ( ! :eels1 z is %[n 9 ,fig4 #cf4 ,illu/ration3 ,fig4 #cf4 ,:y %\ld lamps h l>ge bottoms8 ,lamps %\ld h l>ge bottoms s t ! l9e ( gravity may n fall outside ( ! bottom4 ,:]e mu/ ! l9e ( gravity 9 a body always fall8 ,x mu/ always fall )9 ! base ( t body1 or ! body w be ov]turn$4 ,h[ mu/ a lean+ t[] be built s z n to fall8 ,x mu/ be built s t ! l9e ( gravity w fall )9 its base4 ,:y d we lean back :5 c>ry+ a load 9 front ( u8 ,we lean back s t ! l9e ( gravity may be kept directly ov] our feet4 ,:y does a p]son /&+ up 9 a wagon fall :5 ! wagon is sudd5ly mov$8 ,because ! feet1 be+ 9 contact ) ! wagon1 move ) x be=e ! motion ext5ds to ! re/ ( ! body1 ?us ?r[+ ! l9e ( gravity beh9d ! feet2 h5ce1 ! p]son mu/ fall1 unless support$4 ,:y does a p]son /&+ up 9 a wagon fall :5 ! wagon is sudd5ly /opp$8 ,because ! feet1 be+ 9 contact ) ! wagon1 are sudd5ly /opp$1 :ile ! body /ill moves =w>d1 ?us ?r[+ ! l9e ( gravity ahead ( ! feet2 h5ce1 ! p]son mu/ fall1 unless support$4 ,:y d animals ) f\r feet /& firm] ?an ^? ) only two feet8 ,because ! f\r feet af=d a l>g] base to /& ^u ?an ! two feet d1 &1 !re=e1 support ! c5tre ( gravity bett]4 ,:y c a horse or a c[ rema9 /&+ = _m h\rs )\t seem+ to be we>y8 ,because _! f\r feet af=d a good support to ! c5tre ( gravity4 ,:y does a p]son :o is /&+ soon become we>y8 ,because x requires a con/ant ef=t to keep ! l9e ( gravity ov] ! feet1 & ?is soon produces we>9ess4 ,:y c a p]son sit long] ?an he c /&8 ,because ! c5tre ( gravity is l[]1 :5 he is sitt+1 ?an :5 he is /&+2 h5ce1 x requires less /r5g? to support ! body 9 a sitt+ position4 ,:y c a p]son lie d[n long] ?an he c sit or /&8 ,because ! c5tre ( gravity is ne>e/ ! e>? :5 he is ly+ d[n1 & x requires no ef=t to rema9 9 t position4 ,h[ d we measure "t8 ,we measure "t by means ( a p5dulum1 su* z is us$ 9 a common clock4 ,h[ does ! p5dulum move8 ,! p5dulum moves regul>ly to & fro1 f ! l9e ( gravity4 ,does ! p5dulum v>y any 9 its vibrations1 or ! "t ( mov+ to & fro8 ,! p5dulum does n v>y any 9 its vibrations4 ,illu/ration3 ,fig4 #cg4 ,:y does ! p5dulum keep mov+8 ,:5 ! p5dulum is at ,a1 9 ,fig4 #cg1 gravity causes x to desc5d to ,c1 & ! motion x ga9s :ile fall+ to ,c c>ries x up to ,b2 gravity !n causes x to desc5d to ,c1 & ! motion x ga9s :ile fall+ to ,c c>ries x back to ,a aga94 ,:at helps to keep ! p5dulum 9 motion8 ,! works inside ( ! clock help to keep ! p5dulum 9 motion4 ,h[ long mu/ ! p5dulum be1 s z to tick once 9 e second8 ,! p5dulum mu/ be ?irty-n9e in*es long4 ,h[ does x tick :5 ! p5dulum is %ort5$8 ,x ticks m rapidly4 ,h[ does x tick :5 ! p5dulum is l5g!n$8 ,x ticks m sl[ly4 ,h[ !n does cold affect a clock8 ,cold makes ! clock g fa/] by %ort5+ ! p5dulum4 ,h[ does heat affect a clock8 ,heat makes ! clock g m sl[ly by l5g!n+ ! p5dulum4 ,h[ may ! p5dulum always be kept ( ! same l5g?8 ,by hav+ ! weight at ! bottom ( ! p5dulum1 s t x may be rais$ or l[]$ by means ( a screw4 ,specific ,gravity4 ,^u :at does ! weight ( a body1 :5 9 ! air1 dep5d8 ,! weight ( a body dep5ds ^u ! =ce ) :i* x is drawn t[>ds ! e>?4 ,:at is ?is attractive =ce call$8 ,x is call$ gravitation or gravity4 ,:at is gravity8 ,gravity is ! weight ( any body4 ,:at is specific gravity8 ,specific ,gravity is ! weight ( any body1 comp>$ ) an equal bulk ( wat]4 ,d sub/ances weigh z mu* 9 wat] z !y d 9 air8 ,no2 !y d n weigh s mu*4 ,:5 we drop lead 9 a vessel full ( wat]1 :at becomes ( ! wat]8 ,! wat] is =c$ ov] ! sides ( ! vessel4 ,h[ mu* wat] is ?us =c$ ov] ! sides ( ! vessel8 ,a quantity equal 9 bulk to ! lead dropp$ into ! vessel4 ,:5 ! wat] ?us displac$ weighs j "o p\nd1 h[ mu* less w ! lead weigh :ile 9 ! wat] ?an x did 9 ! air8 ,x w weigh "o p\nd less4 ,!n h[ mu* less is ! weight ( a body 9 wat] ?an x is 9 air8 ,its weight 9 ! wat] is z mu* less z ! weight ( ! wat] :i* x displaces4 ,:5 a body has great] specific gravity ?an wat]1 :at w x d8 ,x w s9k 9 ! wat]4 ,:5 x has less specific gravity ?an wat]1 :at w x d8 ,x w float on ! surface ( ! wat]4 ,w all p>ts ( ! body be above ! surface ( ! wat]8 ,no2 a "p ( x w s9k into ! wat]4 ,h[ mu* ( x w s9k into ! wat]8 ,x w s9k s z to displace wat] en\gh to balance its own weight4 ,:y does a boat float on ! wat]8 ,because x weighs less ?an a bulk ( wat] ( ! same size z ! boat4 ,:5 a c>go is plac$ on ! boat1 :y does x /ill float8 ,because x /ill weighs less ?an a bulk ( wat] ( ! same size z ! boat4 ,h[ d we make use ( ?is pr9ciple8 ,we make use ( x 9 ! con/ruction ( vessels1 s z to c>ry on trade ) o!r p>ts ( ! _w4 ,:y c ducks & geese float on ! wat]8 ,because _! light1 d[ny fea!rs make _! specific gravity less ?an t ( ! wat]2 h5ce1 !y mu/ float on its surface4 ,:at may be said ( ! specific gravity ( ! human body8 ,:5 ! lungs are fill$ ) air1 ! specific gravity ( ! human body is r less ?an t ( wat]4 ,c a p]son float 9 ! wat]8 ,yes2 if a p]son1 :o _c swim1 w ?r[ 8 head back s t 8 m\? & nose only rema9 above ! wat]1 he may float 9 ?is position = "s "t4 ,:at is ! specific gravity ( fi%8 ,! specific gravity ( fi% is s ne>ly equal to t ( wat]1 t !y c move ab\t any:]e b5ea? its surface4 ,h[ d fi% rise & s9k 9 ! wat]8 ,fi% rise & s9k 9 ! wat] by means ( an air-bladd] 9 _! bodies4 ,h[ does ! air-bladd] help ! fi% to rise or s9k8 ,:5 ! bladd] is fill$ ) air1 ! specific gravity ( ! fi% becomes light]1 & x rises t[>ds ! surface2 & :5 ! air is =c$ out1 ! specific gravity becomes heavi]1 & ! fi% s9ks t[>ds ! bottom4 ,:y does cream rise to ! surface ( milk8 ,because ! specific gravity ( ! cream is less ?an t ( ! milk4 ,:y does oil float on wat]8 ,because ! specific gravity ( ! oil is less ?an t ( ! wat]4 ,:y c a fat p]son float m easily 9 ! wat] ?an a lean p]son8 ,because ! fat r$uces ! specific gravity ( ! body1 s t x floats m easily4 ,:y c a p]son float m easily 9 salt wat] ?an 9 fre% wat]8 ,because salt increases ! weight ( ! wat]1 &1 !re=e1 x buoys up ) m =ce4 ,:at famili> example h we ( ?is8 ,an egg w s9k :5 plac$ 9 fre% wat]2 b if salt be dissolv$ 9 ! wat]1 ! egg w float ne> ! surface4 ,illu/ration3 ,decoration4 ,illu/ration3 ,decoration4 ,,*apt] ,,ix4 ,motion4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:5 is a body said to be 9 motion8 ,a body is 9 motion :5 x is mov+ f "o place to ano!r4 ,:5 is a body said to be at re/8 ,a body is at re/ :5 x is n mov+ f "o place to ano!r4 ,:at is necess>y to give motion to a body8 ,=ce ( "s k9d is necess>y to give motion to a body4 ,h[ long w ! motion giv5 to a body cont9ue8 ,! motion w cont9ue until x is *eck$4 ,:at is necess>y to *eck ! motion ( a body8 ,=ce ( "s k9d is necess>y to *eck its motion4 ,:at =ce is always act+ s z to br+ bodies to a /ate ( re/8 ,! =ce ( gravity1 :i* is con/antly draw+ all bodies to ! e>?4 ,:at else may *eck ! motion ( a body8 ,! air1 ! wat]1 & solids ( all k9ds may *eck ! motion ( a body4 ,9 :at direction w a body move :5 its c\rse is n ob/ruct$8 ,x w move 9 a /raight l9e4 ,:y does a ball /ruck by a bat make a curve to ! e>?8 ,because ! =ce ( gravity gradually ov]comes ! =ce giv5 by ! bat1 s t ! ball moves 9 a curve4 ,:y does a bullet make a curve to ! e>?8 ,because ! =ce ( gravity gradually ov]comes ! =ce giv5 by ! p[d]1 s t ! bullet moves 9 a curve to ! e>?4 ,:5 a p]son aims directly at a m>k "s di/ance f him1 :]e w ! bullet /rike8 ,! bullet w /rike bel[ ! m>k4 ,:y w ! bullet /rike bel[ ! m>k8 ,because ! =ce ( gravity draws x t[>ds ! e>?1 :ile x is go+ f ! gun to ! m>k4 ,:5 a ball atta*$ to a /r+ is :irl$ ar\nd1 z 9 ,fig4 #ch1 :at is ! t5d5cy ( ! ball8 ,! t5d5cy ( ! ball is to fly (f 9 a /raight l9e4 ,illu/ration3 ,fig4 #ch4 ,:at is ! =ce t5d+ to make ! ball fly (f call$8 ,x is call$ c5trifugal =ce4 ,:at keeps ! ball f fly+ (f8 ,! /r+ keeps ! ball f fly+ (f4 ,:at is ! =ce ex]t$ by ! /r+ call$8 ,x is call$ c5tripetal =ce4 ,:at !n is c5trifugal =ce8 ,x is ! =ce t5d+ to fly (f f ! c5tre4 ,:at is c5tripetal =ce8 ,x is ! =ce t5d+ to draw t[>ds ! c5tre4 ,:y does mud fly (f f ! :eel ( a wagon :5 9 motion8 ,because ! motion ( ! :eel gives c5trifugal =ce to ! mud1 & causes x to fly (f4 ,:at does ! rim ( a :eel :5 9 motion1 t5d to d8 ,! rim t5ds to fly (f f ! c5tre ( ! :eel4 ,h[ is x prev5t$ f fly+ (f8 ,x is prev5t$ by mak+ ! :eel v /rong1 s t all p>ts ( x are held firmly toge!r4 ,:at does ?is c5trifugal =ce sometimes cause8 ,! c5trifugal =ce is s great t x sometimes causes gr9d-/ones & mill-/ones1 :5 revolv+ rapidly1 to bur/ into pieces4 ,:at becomes ( ^! /ones :5 !y bur/8 ,:5 !y bur/1 _! pieces fly (f 9 diff]5t directions1 do+ m or less injury to :atev] ob/ructs _! c\rse4 ,:5 a horse turns a corn]1 :y does ! rid] lean 9 ! direction 9 :i* ! horse is turn+8 ,he leans s z to ov]come ! c5trifugal =ce1 & is ?us prev5t$ f fall+ (f ! horse4 ,h[ are c>s prev5t$ f runn+ (f ! track1 :ile turn+ a curve8 ,! out] rail is made high] ?an ! inn] rail1 s z to ov]come ! t5d5cy ( ! c>s to run (f ! track4 ,:at gr& example h we ( ! action ( ^! two =ces8 ,! e>? & o!r planets t move ar\nd ! sun1 are kept 9 _! places by ! action ( ^! two =ces4 ,:5 a ball /rikes a solid body & b\nds back1 :at is t motion call$8 ,x is call$ reflect$ motion4 ,at :at angle does ! ball leave ! solid body8 ,x b\nds (f f ! solid body1 s t ! angle ( reflection is always equal to ! angle ( incid5ce1 z is %[n 9 ,fig4 #ci4 ,illu/ration3 ,fig4 #ci4 ,h[ may a /one be skipp$ on a smoo? pond8 ,a /one may be skipp$1 by ?r[+ x s obliquely t ! wat] w cause x to b\nd (f f its surface4 ,:5 a boat moves across a riv] at ! rate ( f\r miles an h\r1 & ! curr5t runs f\r miles an h\r1 9 :at direction w ! boat g8 ,! boat w g diagonally across ! riv]4 ,:y w ! boat g diagonally across ! riv]8 ,because ! boat w be c>ri$ z f> d[n ! riv] z ! riv] is wide4 ,if ! riv] be "o mile wide1 !n ! boat1 :ile cross+1 w be c>ri$ d[n x "o mile4 ,h[ d boatm5 ov]come ?is difficulty8 ,!y ov]come ?is by r[+ ! boat t[>ds a po9t high] up ! /ream4 ,does x take long] to cross a /ream :5 ! curr5t is /rong8 ,yes2 because ! boat is c>ri$ f>!r d[n ! /ream by ! curr5t1 & x mu/1 !re=e1 g a great] di/ance 9 cross+4 ,:y is a p]son apt to fall :5 he jumps f a wagon t is mov+8 ,because 8 body p>takes ( ! motion ( ! wagon & moves on aft] 8 feet are /opp$ by ! gr\nd1 s t he falls =w>ds4 ,h[ c he prev5t fall+8 ,he c prev5t fall+ by jump+ 9 ! same direction z t 9 :i* ! wagon is mov+4 ,:5 a /one is dropp$ f ! top ( a ma/ ( a vessel1 :]e does x fall8 ,! /one falls at ! bottom ( ! ma/4 ,:y does ! /one fall at ! bottom ( ! ma/8 ,because x p>takes ( ! motion ( ! vessel1 & is c>ri$ =w>d :ile fall+4 ,:5 a ball is ?r[n p]p5dicul>ly into ! air by a p]son on a boat1 :]e does ! ball fall8 ,! ball falls back into ! p]son's h&1 al?\gh ! boat may h c>ri$ him sev]al feet :ile ! ball 0 9 ! air4 ,:y does ! ball fall back into 8 h&8 ,because x p>takes ( ! motion ( ! boat1 & moves z f> z ! boat moves4 ,:5 a /one ?r[n f a c> is aim$ at a po/1 :]e w x /rike8 ,! /one w /rike ahead ( ! po/4 ,h[ f> ahead ( ! po/ w ! /one /rike8 ,x w /rike z f> ahead z ! c> moves :ile ! /one is go+ to ! po/4 ,:]e mu/ we aim s z to hit a bird t is fly+8 ,we mu/ aim ahead ( ! bird4 ,:y mu/ we aim ahead ( ! bird8 ,because ! bird w move a %ort di/ance ?r\gh ! air :ile ! %ot is rea*+ x4 ,:5 a body 9 motion /rikes "o at re/1 is ! =ce felt alike by bo? bodies8 ,! =ce is felt alike by bo? bodies2 ?us1 :5 "o head is /ruck aga9/ ano!r1 bo? are equally hurt4 ,d bodies1 :5 mov+ rapidly1 /rike ) m =ce ?an :5 mov+ sl[ly8 ,yes2 ! =ce ) :i* !y /rike dep5ds ^u _! velocity4 ,:at examples ( ?is =ce may be giv58 ,a nail may be driv5 into a bo>d by a hamm]1 :5 x falls rapidly ^u ! nail2 a bullet may be %ot ?r\gh a plank2 & ev5 a tall[ c&le1 :5 %ot f a gun1 may move ) velocity en\gh to pass ?r\gh a p9e bo>d4 ,:y d l>ge bodies />t sl[ly8 ,because x takes "s "t = ! =ce to rea* all p>ts ( !m4 ,:y is x difficult = horses to />t a load$ wagon8 ,because !y mu/ pull "s "t be=e ! =ce rea*es all p>ts ( ! wagon1 caus+ x to move4 ,:y is ma*9]y sl[ at />t+8 ,because x requires "t = ! =ce appli$ to rea* all p>ts ( ! ma*9]y4 ,:5 two solid bodies1 mov+ sl[ly1 /rike aga9/ ea* o!r1 :at takes place8 ,!y are pu%$ (f f ea* o!r 9 opposite directions4 ,:i* body is pu%$ (f ! m rapidly8 ,! "o hav+ ! less weight1 is pu%$ (f ! m rapidly4 ,:5 ! o>s ( a boat pu% aga9/ ! wat]1 :at takes place8 ,! boat & ! wat] move 9 opposite directions4 ,:5 ! w+s ( a bird /rike ! air1 :at takes place8 ,! bird & ! air move 9 opposite directions4 ,h[ c a duck or a goose swim 9 ! wat]8 ,! toes ( a duck or a goose are jo9$ toge!r by a web :i* makes ! foot broad1 l a paddle2 & :5 ^! broad feet are press$ aga9/ ! wat]1 ! duck or ! goose moves =w>d4 ,c all birds swim 9 ! wat]8 ,no2 only ^? birds c swim ^: toes are jo9$ toge!r by a web1 ?us giv+ !m a broad foot to be pu%$ aga9/ ! wat]4 ,:at is produc$ by ! rubb+ ( bodies toge!r8 ,friction is produc$ by rubb+ bodies toge!r4 ,:at does friction t5d to d8 ,friction t5ds to *eck ! motion ( bodies4 ,h[ d we less5 ! friction 9 ma*9]y8 ,we less5 ! friction 9 ma*9]y by oil+ ! p>ts :]e !y rub toge!r4 ,h[ are waves produc$ 9 ! wat]8 ,waves are produc$ by ! friction ( ! air ^u ! wat]4 ,:at causes ! wat] to fl[ 9 creeks & riv]s8 ,! attraction ( gravitation1 :i* causes wat] always to fall to its l[e/ level4 ,:at ret>ds ! curr5t ( wat] 9 /reams8 ,! friction1 caus$ by ! wat] rubb+ aga9/ ! banks & bottoms ( ! /reams1 ret>ds _! curr5t4 ,9 :at "p ( a /ream is ! curr5t ! /ronge/8 ,x is /ronge/ 9 ! middle ( a /ream1 because !re is less friction !re4 ,:at ret>ds ! fl[ ( wat] ?r\gh a pipe8 ,! friction ( ! wat] aga9/ ! sides ( ! pipe1 ret>ds its fl[ v mu*4 ,:y d sudd5 turns 9 a pipe *eck ! fl[ ( wat] ?r\gh x8 ,because e turn 9 ! pipe increases ! friction made by ! wat]4 ,:y does a wagon-:eel turn ar\nd :5 ! wagon moves8 ,because ! friction betwe5 ! :eel & ! e>?1 prev5ts ! :eel f slid+ along4 ,:y c a /eam-eng9e draw a tra9 ( heavy c>s8 ,because ! friction1 betwe5 ! :eels & ! rails1 causes ! :eels to turn ar\nd in/ead ( slid+2 & ?us ! eng9e moves =w>d draw+ ! c>s ) x4 ,:y is s& sometimes put on ! rails8 ,s& is put on ! rails to increase ! friction betwe5 ! :eels & ! rails1 s t ! eng9e may />t a heavi] tra94 ,:y d we use sleighs :5 !re is sn[ on ! gr\nd8 ,because sleighs slip easily on ! sn[4 ,:y d sleighs slip easily on ! sn[8 ,because !re is b little friction betwe5 ! sleigh & ! sn[4 ,:y d wagons run m heavily :5 ! gr\nd is s(t8 ,because _! :eels !n s9k f>!r into ! e>?1 & ?us ! friction is increas$4 ,:y d wagons run m heavily :5 ! gr\nd is cov]$ ) sn[8 ,because _! :eels s9k into ! sn[1 & ?us ! friction is increas$4 ,:y w a p]son slip d[n ^u ! ice m easily ?an ^u ! e>?8 ,because !re is less friction betwe5 8 feet & ! ice ?an !re is betwe5 8 feet & ! e>?4 ,:y d we put a%es on our walks :5 !y are cov]$ ) ice8 ,we put a%es on our walks to increase ! friction betwe5 ! ice & our feet1 s t we may n slip d[n :5 walk+ on !m4 ,:y is a lock or a brake us$ on a wagon8 ,x is us$ to *eck ! motion ( ! wagon4 ,h[ does a lock *eck ! motion ( ! wagon8 ,! lock is press$ aga9/ ! :eels1 s t en\gh friction is produc$ to *eck ! motion ( ! wagon4 ,:y does x require m =ce to draw a ru/y pl\gh ?r\gh ! gr\nd1 ?an to draw "o t is bright & smoo?8 ,because ! ru/ increases ! friction betwe5 ! pl\gh & ! gr\nd1 & ?is makes m =ce necess>y 9 ord] to move x4 ,:y _c we hold a live eel 9 our h&1 z easily z we c a live fi%8 ,because ! sk9 ( ! eel is s smoo?1 t !re is mu* less friction betwe5 x & our h&1 ?an !re is betwe5 ! fi% & our h&4 ,dry s& or dry a%es spr9kl$ on ! eel w increase ! friction s t x c be held4 ,illu/ration3 ,explor]4 ,illu/ration3 ,decoration4 ,,*apt] ,x4 ,me*anical ,p[]s4 ,lev]4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:at is a lev]8 ,a ,lev] is a rod or b> ( "s k9d us$ = rais+ weights4 ,( :at are lev]s made8 ,lev]s are made ( any solid sub/ance1 su* z wood & iron4 ,:5 a spoon is balanc$ on a cup1 z 9 ,fig4 #dj1 :at may ! spoon be call$8 ,! spoon may !n be call$ a lev]4 ,^u :at does ! spoon re/8 ,x re/s ^u ! edge ( ! cup4 ,illu/ration3 ,fig4 #dj4 ,:at is ! cup on :i* ! spoon re/s call$8 ,x is call$ a ,fulcrum4 ,:at is a fulcrum8 ,a fulcrum is any solid body aga9/ :i* a lev] re/s4 ,:5 ! spoon is call$ a lev]1 :at are ! p>ts on ea* side ( ! fulcrum call$8 ,!y are call$ ! arms ( ! lev]4 ,:at is necess>y1 s t a lev] may balance8 ,! arms ( ! lev] mu/ be ( equal weight1 or !y w n balance4 ,if ! b[l ( ! spoon be fill$ ) wat]1 :at w result8 ,! b[l w s9k1 & ! h&le ( ! spoon w rise4 ,:at w cause ! b[l ( ! spoon to s9k8 ,! weight ( ! wat] 9 x w cause x to s9k4 ,h[ c ! b[l ( ! spoon be prev5t$ f s9k+8 ,by apply+ a =ce to ! h&le ( ! spoon1 equal to ! weight ( ! wat] put 9 ! b[l4 ,:at is ! =ce appli$ to ! h&le call$8 ,x is call$ ! ,p[]4 ,:at ?ree ?+s are always necess>y :5 ! lev] is us$8 ,! p[]1 ! fulcrum1 & ! weight1 are always necess>y :5 ! lev] is us$4 ,:i* ( ^! ?ree ?+s are movable8 ,! p[] & ! weight are movable4 ,:i* "o does n move8 ,! fulcrum does n move4 ,h[ _m k9ds ( lev]s are !re8 ,!re are ?ree k9ds ( lev]s4 ,:at is ! fir/ k9d ( lev]8 ,x is :]e ! fulcrum is betwe5 ! p[] & ! weight1 z is %[n 9 ,fig4 #da4 ,illu/ration3 ,fig4 #da4 ,:5 ! fulcrum is "u ! middle ( ! lev]1 h[ c ! lev] be kept balanc$8 ,! lev] w rema9 balanc$1 s long z ! p[] & ! weight us$ are equal to ea* o!r4 ,:5 ! lev] is mov$1 s t ! fulcrum is ne>] ! weight1 :i* arm ( ! lev] is ! heavi]8 ,! arm t[>ds ! p[]1 because x is ! long] arm4 ,w ! p[] appli$ to ! long arm ( ! lev] be z heavy z ! weight8 ,no2 ! ne>] ! fulcrum is to ! weight1 ! less w be ! p[] ne$$ to balance t weight4 ,h[ w x be :5 ! fulcrum is ne>] to ! p[] ?an x is to ! weight8 ,!n ! p[] mu/ be heavi] ?an ! weight4 ,:5 ! long arm ( ! lev] is twice ! l5g? ( ! %ort arm1 :at w be ! diff]5ce 9 ! weights8 ,"o p\nd appli$ to ! long arm w !n balance two p\nds appli$ to ! %ort arm4 ,^u :at does ! p[] ( a lev] dep5d8 ,x dep5ds ^u h[ mu* ne>] ! fulcrum is plac$ to "o end ( ! lev]1 ?an to ! o!r end4 ,( :at use is ! lev]8 ,x is v useful 9 rais+ heavy bodies4 ,illu/ration3 ,fig4 #db4 ,:at is ! weight to be lift$ 9 ,fig4 #db8 ,! /one is ! weight to be lift$4 ,:]e is ! fulcrum plac$8 ,! fulcrum is plac$ ne> ! /one4 ,:]e is ! p[] appli$8 ,! p[] is appli$ by ! h& to ! long arm ( ! lev]4 ,h[ may a see-saw be made8 ,a see-saw may be made by plac+ a plank or a bo>d across a rail 9 a f5ce1 s t x w balance4 ,is ! see-saw1 z %[n 9 ,fig4 #dc1 an example ( ! lev]8 ,yes2 ! see-saw is an example ( ! lev]4 ,illu/ration3 ,fig4 #dc4 ,:at are ! p>ts ( ! plank on ea* side ( ! f5ce-rail call$8 ,!y are call$ ! arms ( ! lev]4 ,:at is ! fulcrum 9 ! see-saw8 ,! f5ce-rail on :i* x re/s1 is ! fulcrum4 ,:at is ! p[] 9 ! see-saw8 ,! p[] is ! boy on "o end ( ! lev]4 ,:at is ! weight 9 ! see-saw8 ,! weight is ! boy on ! o!r end ( ! lev]4 ,h[ d *ildr5 play at see-saw8 ,by pu%+ aga9/ ! e>? ) _! feet1 ! arms ( ! lev] are alt]nately =c$ to rise & fall 9 ! air1 ?us mak+ a see-saw4 ,:]e mu/ ! fulcrum be :5 ! two boys are ( ! same weight8 ,! fulcrum mu/ be "u ! middle ( ! lev]4 ,:]e mu/ ! fulcrum be :5 "o boy is heavi] ?an ! o!r8 ,! fulcrum mu/ !n be ne>e/ to ! heavi] boy1 s t !y may balance4 ,does x require mu* =ce to play at see-saw8 ,no2 :5 ! see-saw is balanc$1 a v little =ce w cause x to move up & d[n4 ,( :at use is a pair ( scales8 ,a pair ( scales is v useful 9 weigh+ diff]5t sub/ances4 ,illu/ration3 ,fig4 #dd4 ,are ! scales1 z %[n 9 ,fig4 #dd1 an example ( ! lev]8 ,! scales are an example ( ! lev]4 ,:]e is ! fulcrum ( ! scales8 ,! fulcrum is ! po9t on :i* ! lev] re/s4 ,:at is ! weight8 ,! weight is ! lead put 9 "o scale4 ,:at is ! p[]8 ,! p[] is ! sub/ance put 9 ! o!r scale1 s z to balance ! weight4 ,:5 ! lead put 9 "o scale weighs exactly a p\nd1 h[ mu* sug> mu/ be put 9 ! o!r scale to balance ! lead8 ,exactly "o p\nd ( sug> mu/ be put 9 to balance ! lead4 ,= :at is a balance mo/ly us$8 ,a balance is mo/ly us$ = weigh+ heavy bodies4 ,is ! balance a lev]8 ,yes2 ! balance is a lev]4 ,:i* is ! fulcrum 9 ! balance8 ,! fulcrum is ! hook t holds ! balance up4 ,illu/ration3 ,fig4 #de4 ,:at is ! weight8 ,! weight is ! l>ge body hang+ f ! %ort arm ( ! lev]4 ,:at is ! p[]8 ,! p[] is ! small] body hang+ f ! long arm ( ! lev]4 ,9 ,fig4 #de1 ! di/ance f ! fulcrum to ! p[] is t5 times ! di/ance f ! fulcrum to ! weight2 n[1 if ! small body weighs "o p\nd1 h[ mu* mu/ ! l>ge body weigh1 s z to balance x8 ,! l>ge body mu/ weigh t5 p\nds4 ,:5 ! small body weighs t5 p\nds1 h[ mu* mu/ ! l>ge body weigh1 s z to balance x8 ,! l>ge body mu/ weigh t5 times z mu*1 or "o hundr$ p\nds4 ,if ! small] body be mov$ half-way to ! fulcrum1 h[ mu* weight w !n balance x8 ,x w !n take only half ! weight1 or fifty p\nds to balance x4 ,:at o!r famili> example ( ?is k9d ( lev] may be m5tion$8 ,! pump-h&le is a lev] ( ?is k9d4 ,illu/ration3 ,fig4 #df4 ,:at is ! p[]8 ,! p[] is ! =ce appli$ to ! pump-h&le4 ,:at is ! fulcrum8 ,! fulcrum is ! screw t fa/5s ! h&le to ! pump4 ,:at is ! weight8 ,! weight is ! wat] rais$ by ! bucket4 ,are scissors an example ( ! lev]8 ,yes2 scissors are a d\ble lev]4 ,:at is ! fulcrum 9 ! scissors8 ,! fulcrum is ! rivet :i* holds ! two lev]s toge!r4 ,:at is ! p[]8 ,! p[] is ! =ce appli$ by ! f+]s4 ,:at is ! weight8 ,! weight is ! pap]1 or o!r sub/ance1 to be cut by ! scissors4 ,c scissors be made v /rong8 ,yes2 "s scissors are made s /rong t !y are us$ = cutt+ iron1 t91 & z9c4 ,:at o!r useful in/rum5ts are made ^u ! same pr9ciple z ! scissors8 ,su* in/rum5ts z nipp]s1 p9c]s1 tweez]s1 & blacksmi?'s tongs4 ,:at is ! second k9d ( lev]8 ,x is :]e ! weight is betwe5 ! p[] & ! fulcrum1 z is %[n 9 ,fig4 #dg4 ,illu/ration3 ,fig4 #dg4 ,( :at use is ?is k9d ( lev]8 ,x is v useful 9 lift+ heavy weights a %ort di/ance f ! e>?4 ,:at example is !re ( ?is k9d ( lev]8 ,! door on its h+es is a lev] ( ?is k9d4 ,:at is ! fulcrum8 ,! h+es are ! fulcrum4 ,:at is ! weight8 ,! door is ! weight4 ,:at is ! p[]8 ,! =ce t op5s or %uts ! door is ! p[]4 ,:at o!r examples ( ?is k9d ( lev] h we8 ,we h an example 9 ! lid ( ! tea-kettle1 & 9 ! cov] ( ! ink-/&1 :5 !y are fa/5$ on by h+es4 ,:at is ! ?ird k9d ( lev]8 ,x is :]e ! p[] is betwe5 ! fulcrum & ! weight1 z is %[n 9 ,fig4 #dh4 ,illu/ration3 ,fig4 #dh4 ,:at examples ( ?is k9d ( lev] h we 9 common use8 ,! %ovel1 ! spade1 & ! pit*-=k1 are lev]s ( ?is k9d4 ,:at is ! fulcrum8 ,"o h& is ! fulcrum4 ,:at is ! p[]8 ,! o!r h& is ! p[]4 ,:at is ! weight8 ,! e>? rais$ on ! %ovel is ! weight4 ,:at o!r famili> example h we ( ?is k9d ( lev]8 ,! fi%+-rod is an example ( ?is k9d4 ,"o h& is ! fulcrum1 ! o!r h& is ! p[]1 & ! l9e1 ) ! fi%1 is ! weight4 ,?is is made pla9 by ,fig4 #di1 repres5t+ a lad j draw+ a fi% out ( ! wat]4 ,illu/ration3 ,fig4 #di4 ,!re are sev]al o!r examples ( ?is k9d ( lev]2 w y "n "s ( !m8 ,yes2 brooms1 hoes1 rakes1 & axes are all lev]s ( ?is k9d4 ,:at is ! fir/ k9d ( lev] m5tion$8 ,x is :]e ! fulcrum is betwe5 ! p[] & ! weight1 z 9 ,fig4 #ej4 ,illu/ration3 ,fig4 #ej4 ,:at is ! second k9d ( lev] m5tion$8 ,x is :]e ! weight is betwe5 ! p[] & ! fulcrum1 z 9 ,fig4 #ea4 ,illu/ration3 ,fig4 #ea4 ,:at is ! ?ird k9d ( lev] m5tion$8 ,x is :]e ! p[] is betwe5 ! fulcrum & ! weight1 z 9 ,fig4 #eb4 ,illu/ration3 ,fig4 #eb4 ,:eel & ,axle4 ,:at o!r way h we = rais+ weights8 ,we h ! :eel & axle1 z is %[n 9 ,fig4 #ec4 ,illu/ration3 ,fig4 #ec4 ,:at is ! :eel & axle8 ,! :eel & axle is only ano!r =m ( ! lev]4 ,:]e is ! p[] appli$8 ,! p[] is appli$ to ! rope :i* passes ar\nd ! :eel4 ,:]e is ! weight8 ,! weight is ! bucket atta*$ to ! rope :i* passes ar\nd ! axle4 ,:]e is ! fulcrum8 ,! fulcrum is ! frame on :i* ! ends ( ! axle re/4 ,is ! p[] appli$ to ! :eel equal to ! weight to be rais$8 ,no2 ! p[] is always less ?an ! weight to be rais$4 ,^u :at d ! p[] & ! weight dep5d8 ,!y dep5d ^u ! size ( ! :eel & ! axle4 ,:5 ! diamet] ( ! :eel is t5 times ! diamet] ( ! axle1 h[ mu* w "o p\nd raise8 ,"o p\nd appli$ to ! :eel1 w !n raise t5 p\nds on ! axle4 ,:at is a w9dlass8 ,a w9dlass is ano!r =m ( ! :eel & axle1 z is %[n 9 ,fig4 #ed4 ,illu/ration3 ,fig4 #ed4 ,:at is us$ 9 a w9dlass 9 place ( ! :eel8 ,a crank or h&le is us$ 9 place ( ! :eel4 ,does ! crank take ! place ( ! :eel8 ,yes2 :5 ! crank is turn$1 x =ms a circle ! same z ! outside ( ! :eel4 ,to :at use is ! w9dlass (t5 appli$8 ,! w9dlass is (t5 us$ to draw wat] f wells4 ,pulley4 ,:at is a pulley8 ,a pulley is a :eel ) a groove or holl[ cut 9 its edge4 ,:at is ! groove =8 ,! groove is cut s t a rope may move ov] ! :eel )\t slipp+ (f4 ,illu/ration3 ,fig4 #ee4 ,9 ,fig4 #ee1 :]e is ! p[] appli$8 ,! p[] is appli$ to "o end ( ! rope by ! h&4 ,:]e is ! weight8 ,! weight is atta*$ to ! o!r end ( ! rope4 ,:5 ! p[] & ! weight are equal1 :at d !y d8 ,!y balance ea* o!r1 & nei!r ( !m w move4 ,:5 ! p[] is great] ?an ! weight1 :at takes place8 ,! weight is !n lift$ up4 ,( :at use is ! s+le pulley8 ,! s+le pulley is us$ = hoi/+ flags to ! top ( high poles1 = rais+ sails to ! topma/s ( vessels1 & = rais+ weights to ! upp] /ories ( mills & factories4 ,h[ _m pulleys are ne$$1 :5 a horse is to raise ! weight8 ,:5 a horse is to raise ! weight1 two pulleys are ne$$1 z may be se5 9 ,fig4 #ef4 ,illu/ration3 ,fig4 #ef4 ,to :at use d f>m]s apply ! pulley8 ,!y arrange ! pulleys s z to lift ! hay into _! b>ns1 by means ( a horse2 ?us sav+ !mselves mu* h>d labor4 ,incl9$ ,plane4 ,:5 "o end ( a plank is rais$ up1 :ile ! o!r end rema9s on ! floor1 is its surface level8 ,no2 its surface is n level4 ,:at may ! surface ( ! plank be call$8 ,x may be call$ an incl9$ surface1 or an incl9$ plane4 ,:at is an incl9$ plane8 ,an incl9$ plane is a surface t incl9es upw>ds or d[nw>ds4 ,( :at use is ! incl9$ plane8 ,x aids v mu* 9 rais+ weights4 ,are all planes incl9$ alike8 ,no2 "s planes are mu* /eep] ?an o!rs4 ,illu/ration3 ,fig4 #eg4 ,9 ,fig4 #eg1 :]e is ! p[]8 ,! p[] is at ,p4 ,:]e is ! weight8 ,! weight is at ,w4 ,^u :at does ! p[] & ! weight dep5d8 ,!y dep5d ^u ! height & ! l5g? ( ! incl9$ plane4 ,:5 an incl9$ plane is t5 feet long & only "o foot high1 h[ mu* w "o p\nd at ,p balance8 ,"o p\nd at ,p w balance t5 p\nds at ,w4 ,:5 an incl9$ plane t5 feet long is two feet high1 h[ mu* w "o p\nd at ,p balance8 ,"o p\nd at ,p w !n balance only five p\nds at ,w2 because ! plane is five times z long z x is high4 ,:]e else may ! p[] be ex]t$8 ,! p[] may be ex]t$ beh9d ! weight1 z 9 ,fig4 #eh4 ,illu/ration3 ,fig4 #eh4 ,w any m p[] be ne$$ beh9d ! weight ?an be=e x8 ,no2 ! p[] requir$ is ! same 9 bo? cases4 ,w\ld x require z mu* p[] to roll b>rels into a wagon z to lift !m 98 ,no2 !y c be roll$ into a wagon mu* m easily ?an lift$ 94 ,c !y be tak5 out ( ! wagon any m easily on an incl9$ plane ?an )\t "o8 ,yes2 !y c be tak5 out m easily on an incl9$ plane4 ,:y are drays1 us$ 9 cities1 made 9 ! =m ( ! incl9$ plane8 ,s t b>rels & hog%eads may ! m easily be roll$ on !m4 ,are our /airs 9 ! =m ( ! incl9$ plane8 ,yes2 !y are incl9$ planes ) /eps cut 9 !m to make ! asc5t easy4 ,:y are h\se-ro(s made 9 ! =m ( ! incl9$ plane8 ,s t ! wat] fall+ on !m may run (f readily4 ,:at famili> example ( ! incl9$ plane may be m5tion$8 ,! hills1 all ov] ! c\ntry1 are s _m incl9$ planes4 ,( :at use are ! hills8 ,! hills c>ry (f ! wa/e wat] f ! e>?1 s t x is kept dry en\gh = plants to gr[4 ,:at o!r example ( ! incl9$ plane may be m5tion$8 ,! b$s ( ! creeks & riv]s are s _m incl9$ planes d[n :i* _! wat]s fl[4 ,w$ge4 ,:at is a w$ge8 ,a w$ge is a d\ble incl9$ plane1 z is repres5t$ 9 ,fig4 #ei4 ,illu/ration3 ,fig4 #ei4 ,( :at use is ! w$ge8 ,! w$ge is us$ 9 splitt+ logs ( wood & blocks ( /one4 ,= :at o!r purposes is ! w$ge us$8 ,! w$ge is us$ to fa/5 h&les 9 hamm]s1 hat*ets1 axes1 & hoes4 ,h[ is p[] appli$ to ! w$ge8 ,p[] is appli$ to ! w$ge by means ( sudd5 bl[s f a hamm]4 ,:at prev5ts ! w$ge f fly+ back aft] ! bl[8 ,! friction betwe5 ! w$ge & ! o!r body1 keeps x f fly+ back4 ,:at in/rum5ts are made 9 ! =m ( a w$ge8 ,knife-blades1 hat*ets1 axes1 razors1 & cutt+ in/rum5ts ( ne>ly all k9ds1 are 9 ! =m ( ! w$ge4 ,screw4 ,:at is a screw8 ,a screw is ano!r =m ( ! incl9$ plane4 ,:]e is ! incl9$ plane on a screw8 ,x beg9s at ! bottom ( ! screw1 & w9ds ar\nd & ar\nd ! screw until x rea*es ! top1 z is %[n 9 ,fig4 #fj4 ,illu/ration3 ,fig4 #fj4 ,:at is ?is incl9$ plane call$8 ,x is call$ ! ?read ( ! screw4 ,h[ d ! ?reads affect ! screw8 ,:5 ! ?reads are f> ap>t1 ! incl9$ plane is /eep2 b x becomes less /eep ! ne>] ! ?reads are toge!r4 ,:5 w ! screw ex]t ! mo/ p[]8 ,! screw w ex]t ! mo/ p[]1 :5 its ?reads are ne>e/ toge!r4 ,( :at use are screws1 su* z is %[n 9 ,fig4 #fj8 ,screws are us$ to fa/5 h+es & bolts on doors & %utt]s1 & to fa/5 pieces ( wood toge!r 9 ! con/ruction ( h\ses1 boats1 wagons1 & o!r ?+s4 ,= :at o!r purposes is ! screw us$8 ,! screw is us$ :]e mu* p[] is ne$$1 z 9 ! vise2 :]e pressure is desir$1 z 9 copy+ lett]s1 & 9 co9+ money2 &1 also1 = squeez+ ! juice f apples1 grapes1 & sug>-cane4 ,illu/ration3 ,fig4 #fa4 ,9 :at does a screw l t 9 ,fig4 #fa "w8 ,x works 9 a nut :i* has ?reads cut on ! inside1 s t ! ?reads ( ! screw move 9 !m4 ,:]e is ! p[] appli$8 ,! p[] is appli$ to ! lev]4 ,c heavy bodies be rais$ by means ( ?is screw8 ,yes2 load$ c>s1 & ev5 heavy build+s1 may be rais$ by means ( a screw ( ?is k9d4 ,illu/ration3 ,sew+ ma*9e4 ,illu/ration3 ,decoration4 ,,*apt] ,,xi4 ,electricity4 ,illu/ration3 ,illu/rat$ ,capital ,w ,:5 a cat's back is rubb$ 9 ! d>k1 :at does x give (f8 ,x gives (f small sp>ks4 ,:at are ^! small sp>ks call$8 ,!y are call$ electric sp>ks1 or electricity4 ,if a horse be rubb$ 9 ! w9t] :5 x is d>k1 :at w be giv5 (f f him8 ,electricity w be giv5 (f f ! horse4 ,:5 seal+-wax is rubb$ ) a silk h&k]*ief1 or a piece ( flannel1 :at is produc$8 ,electricity is produc$ 9 ! seal+-wax4 ,:at w ?is electricity 9 ! seal+-wax d8 ,x w attract bits ( pap]1 /raw1 fea!rs1 & hairs1 :5 x is held ne> !m4 ,:at o!r sub/ance w act ! same z ! seal+-wax8 ,a dry glass tube w act 9 ! same mann] :5 rubb$4 ,:]e is electricity f\nd8 ,electricity is f\nd 9 e body1 & 9 e ?+4 ,h[ is electricity develop$8 ,electricity is develop$ by motion1 by friction1 & by almo/ e *ange t takes place4 ,is electricity f\nd 9 ! air8 ,yes2 ! air is almo/ con/antly electrifi$4 ,) :at is electricity (t5 accompani$8 ,electricity is (t5 accompani$ by heat & light4 ,h[ _m k9ds ( electricity are !re8 ,!re are two k9ds ( electricity4 ,:at are !y call$8 ,!y are call$ positive & negative electricity4 ,:at d ^! two k9ds ( electricity always d8 ,!y always attract ea* o!r4 ,:5 "o body conta9s positive & ! o!r body negative electricity1 :at w ! two bodies d8 ,!y w ru% toge!r4 ,:5 bo? bodies are positive or bo? are negative1 :at w !y d8 ,!y w repel ea* o!r4 ,:5 a body p]mits electricity to pass freely ?r\gh x1 :at is x call$8 ,x is call$ a good conductor ( electricity4 ,:at sub/ances are good conductors ( electricity8 ,metals1 *>coal1 wat]1 animals1 vegetables1 flame1 & smoke4 ,:5 a body does n p]mit ! electricity to pass ?r\gh x1 :at is x call$8 ,x is call$ a non-conductor ( electricity4 ,:at sub/ances are non-conductors ( electricity8 ,gutta-p]*a1 sulphur1 glass1 silk1 wool1 hair1 fea!rs1 cotton1 & pap]4 ,:at is lightn+8 ,lightn+ is electricity pass+ f "o place to ano!r4 ,:5 does lightn+ pass f "o cl\d to ano!r cl\d8 ,:5ev] "o cl\d becomes fill$ ) m electricity ?an ano!r1 ! cl\d hav+ ! mo/ electricity gives (f a portion to ! cl\d hav+ ! lea/ electricity4 ,:5 does lightn+ pass f ! e>? to a cl\d8 ,:5ev] ! e>? conta9s m electricity ?an ! cl\d does4 ,:5 does lightn+ pass f a cl\d to ! e>?8 ,:5ev] ! cl\d conta9s m electricity ?an ! e>? does4 ,h[ ne> are ! cl\ds :5 ! lightn+ comes to ! e>?8 ,! cl\ds are seldom half a mile away :5 ! lightn+ comes f !m to ! e>?4 ,:at noise is made by ! lightn+8 ,! lightn+ passes s quickly ?r\gh ! air1 t x makes a noise call$ ?und]4 ,d we always he> ! ?und] :5 !re is lightn+8 ,no2 ! lightn+ is sometimes s f> away t ! ?und] _c be he>d4 ,:at bodies attract ! lightn+ to ! e>?8 ,tall trees1 /eeples1 high h\ses1 & m\nta9s4 ,does ! lightn+ d any h>m8 ,yes2 x does mu* h>m by de/roy+ trees1 h\ses1 animals1 &1 inde$1 almo/ ev]y?+ 9 its c\rse4 ,:at does lightn+ sometimes d ) build+s8 ,x sets ! build+s on fire s t !y are burn$4 ,h[ are build+s protect$ f injury by lightn+8 ,!y are protect$ by means ( ! lightn+-rod1 :i* 0 inv5t$ by ,dr4 ,frankl94 ,( :at is ! lightn+-rod made8 ,! lightn+-rod is made ( "s metal1 usually ( iron or copp]1 :i* is a good conductor ( electricity4 ,:at does ! lightn+-rod d :5 ! build+ is /ruck8 ,! lightn+-rod conducts ! electricity to ! e>?1 s t x does n injure ! build+4 ,mu/ ! lightn+-rod be high] ?an ! build+8 ,yes2 because ! lightn+ is apt to /rike ! highe/ object4 ,( :at %\ld ! po9t ( ! rod be made8 ,! po9t %\ld be made ( silv] or plat9um1 s t x w always rema9 bright4 ,%\ld ! rod ext5d deep into ! gr\nd8 ,! rod %\ld ext5d f\r or five feet b5ea? ! surface ( ! e>?4 ,:y %\ld a%es or *>coal be put ar\nd ! bottom ( ! rod8 ,because !y are good conductors & w help to conduct ! lightn+ into ! e>?4 ,h[ l>ge %\ld ! lightn+-rod be8 ,if made ( iron1 ! lightn+-rod %\ld be ab\t ?ree-f\r?s ( an in* 9 diamet]4 ,:y is glass put ar\nd ! rod :]e x is jo9$ to ! build+8 ,! glass is a non-conductor1 & prev5ts ! lightn+ f leav+ ! rod4 ,:y is x n safe to /& ne> a fire dur+ a ?und]-/orm8 ,because ! fire is a good conductor1 & sometimes draws ! electricity into ! room4 ,:at "p ( ! room is ! safe/ place8 ,! middle ( a room is ?\ght to be ! safe/ place4 ,is a fea!r-b$ a safe place8 ,yes2 because ! fea!rs are a non-conductor1 & w n attract ! lightn+4 ,is dry air a non-conductor ( electricity8 ,yes2 dry air is a non-conductor ( electricity4 ,:5 are ?und]-/orms mo/ frequ5t8 ,?und]-/orms are m frequ5t 9 summ] ?an 9 w9t]1 & m s 9 ! aft]noon ?an 9 ! morn+4 ,by :at are ?und]-/orms usually att5d$8 ,!y are usually att5d$ by "s *ange 9 ! direction ( ! w9d4 ,:]e d ?und]-/orms g5]ally prevail8 ,!y g5]ally prevail 9 ! l[] regions ( ! air1 ne> ! e>?4 ,:at is ! rapidity ( lightn+8 ,! rapidity ( lightn+ is probably n less ?an #bej1jjj miles 9 a second1 & ! fla% does n exce$ ! million? "p ( a second 9 duration4 ,magnetism4 ,( :at does magnetism treat8 ,magnetism treats ( ! prop]ty ( magnets4 ,:at is a magnet8 ,a magnet is a piece ( iron ore hav+ ! p[] ( attract+ iron & /eel4 ,h[ _m k9ds ( magnets are !re8 ,!re are two k9ds ( magnets3 natural magnets1 & artificial magnets4 ,:at o!r "n is giv5 to a natural magnet8 ,x is call$ a load/one4 ,:]e are natural magnets or load/ones f\nd8 ,!y are dug out ( ! e>?1 & are f\nd mo/ abundantly 9 ,norway & ,sw$54 ,:at is an artificial magnet8 ,an artificial magnet is "o made by magnetiz+ a b> ( /eel4 ,h[ may a b> ( /eel be magnetiz$8 ,a b> ( /eel1 :5 rubb$ on a natural magnet1 becomes magnetiz$4 ,:5 ! b> ( /eel is b5t 9 ! %ape ( a horse-%oe1 :at is x call$8 ,x is !n call$ a horse-%oe magnet1 f its %ape4 ,:]e does a magnetic b> always po9t1 :5 x is made to move easily on a pivot8 ,"o end ( x always po9ts to ! nor?1 & ! o!r end to ! s\?4 ,:at are ! ends ( ! magnet call$8 ,! nor? end is call$ ! positive1 & ! s\? end is call$ ! negative4 ,:at is !re curi\s ab\t ! magnet8 ,! positive end ( "o magnet always attracts ! negative end ( e o!r magnet2 b if ! two positive or ! two negative ends are br\ght toge!r1 !y w repel ea* o!r4 ,:y are artificial magnets made ( /eel8 ,because /eel w rema9 magnetiz$1 b iron soon loses ! magnetic prop]ties4 ,:at is a compass8 ,a compass is an in/rum5t conta9+ a magnetic ne$le1 s balanc$ z to move easily on a pivot4 ,9 :at direction does ?is ne$le always po9t8 ,?is ne$le always po9ts t[>d ! nor?4 ,by :om is ! compass us$8 ,x is us$ by travell]s to guide !m on _! j\rney2 by surveyors to m>k out ! b\nd>y l9es betwe5 diff]5t prop]ties2 & by seam5 to po9t out _! way across ! sea f "o place to ano!r4 ,be=e ! ,m>9]'s ,compass 0 inv5t$1 seam5 7 afraid to v5ture out ( ! sight ( l&1 = fe> ( be+ lo/ on ! ocean2 = !y !n _h no means ( tell+ :]e !y 71 or 9 :at direction to guide _! vessels1 s z to rea* ! l& aga94 ,electro-,magnetism4 ,are magnetism & electricity mu* alike8 ,yes2 !y are s ne>ly alike t _m p]sons ?9k !y are id5tical4 ,:at is an electro-magnet8 ,an electro-magnet is a magnet obta9$ by means ( electricity4 ,( :at is ! magnet made8 ,! magnet is made ( s(t iron1 ar\nd :i* are w\nd a great _m coils ( wire1 & ^! are cov]$ ) silk4 ,h[ is ! s(t iron made into a magnet8 ,! iron is magnetiz$ by ! passage ( electricity ?r\gh ! wire4 ,( :at use is ?is magnet8 ,x is us$ 9 ! electro-magnetic telegraph4 ,:5 & :]e 0 ! fir/ l9e ( telegraph built8 ,! fir/ l9e ( telegraph 0 built 9 #ahdd1 f ,wa%+ton to ,baltimore1 by ,pr(essor ,morse4 ,:at is ! pr9ciple ( ! telegraph8 ,at "o end ( ! telegraph wire is an electrical batt]y1 & at ! o!r end is an electro-magnet4 ,:5 a message is to be s5t1 ! electricity is transmitt$ ?r\gh ! wire to ! s(t iron ( ! electro-magnet1 :i* causes ! iron to move1 & ?is motion is convey$ to ! ma*9]y1 :i* is ne$$ to pr9t ! message 9 lett]s or signals1 s z to be und]/ood4 ,does electricity move rapidly8 ,yes2 its velocity is su* z to move ar\nd ! e>? 9 a qu>t] ( a second4 ,:at is ! electrical batt]y call$8 ,! electrical batt]y is call$ a key4 ,:at is ! electro-magnet call$8 ,! electro-magnet is call$ a receiv]4 ,= :at are ! key & receiv] us$8 ,! key is us$ = s5d+ messages1 & ! receiv] = receiv+ !m4 ,:at mu/ ea* /ation h8 ,ea* /ation mu/ h bo? a key & a receiv]1 s z to s5d z well z receive messages4 ,:at is ! ,atlantic cable8 ,! ,atlantic cable is a telegraphic wire rea*+ across ! ,atlantic ,ocean1 f ,am]ica to ,europe4 ,:5 0 ! fir/ ,atlantic cable laid8 ,! fir/ ,atlantic cable 0 successfully laid 9 #ahff1 betwe5 ,newf\ndl& & ,irel&4 ,x is eighte5 hundr$ & sixty-f\r miles long1 & its success is *iefly due to ,cyrus ,w4 ,field4 ,( :at use is ! ,atlantic cable8 ,! ,atlantic cable =ms a telegraphic connection betwe5 ,europe & ,am]ica1 s t news may be s5t f "o c\ntry to ! o!r 9 a few mom5ts ( "t2 ?us ! p ( ! two cont95ts1 al?\gh s f> ap>t1 c communicate ) ea* o!r _m times 9 a s+le day4 ,illu/ration3 ,fruit b[l4 ,,! ,elem5ts ( ,natural ,philosophy ,by ,e4 ,j4 ,,h\/on1 ,a4,m41 ,pr(essor ( ,physics & ,physical ,geography 9 ! ,c5tral ,high ,s*ool1 ,philadelphia1 ,pa4 ,?is book is int5d$ = ,grad$ ,s*ools1 ,academies1 ,sem9>ies1 ,normal ,s*ools1 etc4 ,x gives ! elem5ts ( ! sci5ce 9 a concise =m & 9 logical sequ5ce1 s t ! book =ms a sy/em ( ,natural ,philosophy1 & n a m]e collection ( disconnect$ facts4 ,x is fully 8up to ! times0 9 e respect1 & gives full descriptions ( ! m important discov]ies lately made 9 ,physical ,sci5ce2 ! ,electric ,light1 ! ,telephone1 ! ,microphone1 ! ,phonograph1 etc41 are all describ$ & illu/rat$4 ,an exam9ation ( ! 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