file :i* includes ! orig9al illu/rations4 ,see #fecei-;h4htm or #fecei-;h4zip3 7https3_/_/www4gut5b]g4org_/ca*e_/epub_/ #fecei_/pg#fecei-;images4html7 or 7https3_/_/www4gut5b]g4org_/files_/#fece i_/fecei-;h4zip7 ,images ( ! orig9al pages are available ?r\gh ,int]net ,ar*ive4 ,see https3_/_/ar*ive4org_/details_/jamescl]k maxwel#jj;glaziala ,transcrib]'s note3 ,text enclos$ by und]scores is 9 italics 7italics74 ,sup]scripts t _c be repres5t$ directly are enclos$ by curly brackets imm$iately aft] a c>et "* 7example3 n?74 ,"s *>act]s might n display prop]ly 9 ?is ,,utf-#h text file 7e4g41 empty squ>es74 ,if s1 ! read] %\ld consult ! html v]sion or ! orig9al page images not$ above4 ,illu/ration3 7cov]7 ,! ,c5tury ,sci5ce ,s]ies ,edit$ by ,sir ,h5ry ,e4 ,roscoe1 ,d4,c4,l41 ,,ll4,d41 ,f4,r4,s4 ,,james ,,cl]k ,,maxwell ,,& ,,mod]n ,,physics 99 99 99 99 99 99 ,! ,c5tury ,sci5ce ,s]ies4 ,,edit$ ,,by ,,sir ,,h5ry ,e4 ,,roscoe1 ,d4,c4,l41 ,f4,r4,s41 ,m4,p4 ,john ,dalton & ! ,rise ( ,mod]n ,*emi/ry4 ,by ,sir ,,h5ry ,e4 ,,roscoe1 ,f4,r4,s4 ,major ,r5nell1 ,f4,r4,s41 & ! ,rise ( ,engli% ,geography4 ,by ,,clem5ts ,r4 ,,m>kham1 ,c4,b41 ,f4,r4,s41 ,presid5t ( ! ,royal ,geographical ,society4 ,ju/us von ,liebig3 8 ,life & ,"w 7#ahjc-ahgc74 ,by ,w4 ,a4 ,,%5/one1 ,f4,i4,c41 ,lectur] on ,*emi/ry 9 ,clifton ,college4 ,! ,h]s*els & ,mod]n ,a/ronomy4 ,by ,,agnes ,m4 ,,cl]ke1 ,au?or ( 8,a ,popul> ,hi/ory ( ,a/ronomy dur+ ! #ai? ,c5tury10 c4 ,*>les ,lyell & ,mod]n ,geology4 ,by ,rev4 ,pr(essor ,t4 ,g4 ,,bonney1 ,f4,r4,s4 ,james ,cl]k ,maxwell & ,mod]n ,physics4 ,by ,r4 ,t4 ,,glazebrook1 ,f4,r4,s41 ,fell[ ( ,tr9ity ,college1 ,cambridge4 ,9 ,prep>ation4 ,mi*ael ,f>aday3 8 ,life & ,"w4 ,by ,pr(essor ,,silvanus ,p4 ,,?ompson1 ,f4,r4,s4 ,humphry ,davy4 ,by ,t4 ,e4 ,,?orpe1 ,f4,r4,s41 ,pr9cipal ,*emi/ ( ! ,gov]nm5t ,laboratories4 ,pa/eur3 8 ,life & ,"w4 ,by ,m4 ,,arm& ,,ruff]1 ,m4,d41 ,director ( ! ,briti% ,in/itute ( ,prev5tive ,m$ic9e4 ,*>les ,d>w9 & ! ,orig9 ( ,species4 ,by ,,edw>d ,b4 ,,p\lton1 ,m4,a41 ,f4,r4,s41 ,hope ,pr(essor ( ,zoology 9 ! ,univ]sity ( ,ox=d4 ,h]mann von ,helmholtz4 ,by ,a4 ,w4 ,r,,ck]1 ,f4,r4,s41 ,pr(essor ( ,physics 9 ! ,royal ,college ( ,sci5ce1 ,london4 ,,cassell ,,company1 ,,limit$1 ,london2 ,p>is ,melb\rne4 99 99 99 99 99 99 ,illu/ration3 ,j4 ,cl]k ,maxwell 7,f a ,photograph ( ! ,picture by ,g4 ,l[es ,dick9son1 ,esq41 9 ! ,hall ( ,tr9ity ,college1 ,cambridge47 ,! ,c5tury ,sci5ce ,s]ies ,,james ,,cl]k ,,maxwell ,,& ,,mod]n ,,physics by ,r4 ,t4 ,,glazebrook1 ,f4,r4,s4 ,fell[ ( ,tr9ity ,college1 ,cambridge ,univ]sity ,lectur] 9 ,ma!matics1 & ,assi/ant ,director ( ! ,cav5di% ,laboratory ,cassell & ,company1 ,limit$ ,london1 ,p>is ,melb\rne #ahif ,all ,rights ,res]v$ ,illu/ration ,,preface4 ,! task ( giv+ "s acc\nt ( ,maxwell's "w--( describ+ ! %>e t he has tak5 9 ! advance ( ,physical ,sci5ce dur+ ! latt] half ( ?is n9ete5? c5tury--has prov$ no light lab\r4 ,! problems :i* he attack$ are ( su* magnitude & complexity1 t ! attempt to expla9 !m & _! importance1 satisfactorily1 )\t ! aid ( symbols1 is almo/ =$oom$ to failure4 ,h[ev]1 ! attempt has be5 made1 9 ! belief t !re are _m :o1 ?\gh !y _c foll[ ! ma!matical analysis ( ,maxwell's "w1 h suffici5t g5]al k ( physical ideas & pr9ciples to make an acc\nt ( ,maxwell & ( ! developm5t ( ! tru?s t he discov]$1 subjects ( intellig5t int]e/4 ,maxwell's life 0 writt5 9 #ahhb by two ( ^? :o 7 mo/ intimately connect$ ) him1 ,pr(essor ,lewis ,campbell & ,dr4 ,g>nett4 ,_m ( ! biographical details ( ! e>li] "p ( ?is book are tak5 f _! "w4 ,my ?anks are due to !m & to _! publi%]s1 ,messrs4 ,macmillan1 = p]mission to use any ( ! lett]s :i* appe> 9 _! biography4 ,i tru/ t my brief acc\nt may be suffici5t to induce _m to read ,pr(essor ,campbell's 8,life & ,lett]s10 ) a view ( le>n+ m ( ! inn] ?\ghts ( "o :o has left s /rong an impr9t on all he und]took1 & 0 s deeply lov$ by all :o knew him4 ,r4 ,t4 ,g4 ,cambridge1 ,decemb]1 #ahie4 ,,cont5ts4 ,,*apt] ,,page ,i4 ,,e>ly ,,life #i ,,ii4 ,,und]graduate ,,life ,,at ,,cambridge #bh ,,iii4 ,,e>ly ,,rese>*es--,,pr(essor ,,at ,,ab]de5 #ch ,,iv4 ,,pr(essor ,,at ,,k+',s ,,college1 ,,london--,,life ,,at ,,gl5lair #ed ,v4 ,,cambridge--,,pr(essor ,,or ,,physics #fj ,,vi4 ,,cambridge--,,! ,,cav5di% ,,laboratory #gc ,,vii4 ,,sci5tific ,,"w--,,col\r ,,vision #ic ,,viii4 ,,sci5tific ,,"w--,,molecul> ,,!ory #ajh ,,ix4 ,,sci5tific ,,"w--,,electrical ,,!ories #adh ,x4 ,,developm5t ,,( ,,maxwell',s ,,!ory #bjb ,,james ,,cl]k ,,maxwell ,,& ,,mod]n ,,physics4 ,,*apt] ,i4 ,,e>ly ,,life4 8,"o :o has enri*$ ! inh]itance left by ,newton & has consolidat$ ! "w ( ,f>aday--"o :o impell$ ! m9d ( ,cambridge to a fre% c\rse ( real inve/igation--has cle>ly e>n$ 8 place 9 human memory40 ,x 0 ?us t ,pr(essor ,lewis ,campbell & ,mr4 ,g>nett began 9 #ahhb _! life ( ,james ,cl]k ,maxwell4 ,! ye>s :i* h pass$1 s9ce t date1 h all t5d$ to /r5g!n ! belief 9 ! greatness ( ,maxwell's "w & 9 ! f]tility ( 8 g5ius1 :i* has inspir$ ! lab\rs ( ^? :o1 n 9 ,cambridge only1 b ?r\gh\t ! _w1 h aid$ 9 develop+ ! se$s s[n by him4 ,my object 9 ! foll[+ pages w be to give "s v brief acc\nt ( 8 life & writ+s1 9 a =m :i* may1 ,i hope1 enable _m to realise :at ,physical ,sci5ce owes to "o :o 0 to me a mo/ k9d fri5d z well z a rev]$ ma/]4 ,! ,cl]ks ( ,p5icuik1 f :om ,cl]k ,maxwell 0 desc5d$1 7 a di/+ui%$ family4 ,sir ,john ,cl]k1 ! great-great-gr&fa!r ( ,cl]k ,maxwell1 0 a ,b>on ( ! ,ex*equ] 9 ,scotl& f #agjg to #agee2 he 0 also "o ( ! ,commission]s ( ! ,union1 & 0 9 _m ways an accompli%$ s*ol>4 ,8 second son ,george m>ri$ a fir/ c\s91 ,doro!a ,maxwell1 ! heiress ( ,middlebie 9 ,dumfries%ire1 & took ! "n ( ,maxwell4 ,by ! dea? ( 8 eld] bro!r ,james 9 #aghb ,george ,cl]k ,maxwell succe$$ to ! b>onetcy & ! prop]ty ( ,p5icuik4 ,be=e ?is "t he _h become involv$ 9 m9+ & manufactur+ speculations1 & mo/ ( ! ,middlebie prop]ty _h be5 sold to pay 8 debts4 ,! prop]ty ( ,sir ,george ,cl]k ,maxwell desc5d$ 9 #agih to 8 two gr&sons1 ,sir ,george ,cl]k & ,mr4 ,john ,cl]k ,maxwell4 ,x _h be5 arrang$ t ! y\ng] ( ! two 0 to take ! rema9s ( ! ,middlebie prop]ty & to assume ) x ! "n ( ,maxwell4 ,sir ,george ,cl]k 0 memb] = ,midlo?ian1 & held (fice "u ,sir ,rob]t ,peel4 ,john ,cl]k ,maxwell 0 ! fa!r ( ,james ,cl]k ,maxwell1 ! subject ( ?is sket*4#a ,john ,cl]k ,maxwell liv$ ) 8 wid[$ "m 9 ,ed9burgh until h] dea? 9 #ahbd4 ,he 0 a lawy]1 & f "t to "t did "s little bus9ess 9 ! c\rts4 ,at ! same "t he ma9ta9$ an int]e/ 9 sci5tific pursuits1 especially ^? ( a practical nature4 ,pr(essor ,campbell tells u ( an endeav\r to devise a bell[s :i* w\ld give a cont9u\s draught ( air4 ,9 #ahca he contribut$ to ! ,ed9burgh ,m$ical & ,philosophical ,j\rnal a pap] entitl$ 8,outl9es ( a ,plan = comb9+ ,ma*9]y ) ! ,manual ,pr9t+ ,press40 ,9 #ahbf ,john ,cl]k ,maxwell m>ri$ ,miss ,frances ,cay1 ( ,nor? ,*>lton1 ,nor?umb]l&4 ,= ! fir/ few ye>s ( _! m>ri$ life _! home 0 9 ,ed9burgh4 ,! old e/ate ( ,middlebie _h be5 greatly r$uc$ 9 ext5t1 & !re 0 n a h\se on x 9 :i* ! laird c\ld live4 ,h[ev]1 soon aft] 8 m>riage1 ,john ,cl]k ,maxwell pur*as$ ! adjo9+ prop]ty ( ,gl5lair & built a mansion-h\se = himself & 8 wife4 ,mr4 ,maxwell sup]9t5d$ ! build+ "w4 ,! actual work+ plans = "s fur!r additions made 9 #ahdc 7 8 h&iwork4 ,a g>d5 0 laid out & plant$1 & a dre>y /ony wa/e 0 conv]t$ into a pleasant home4 ,= "s ye>s aft] he settl$ at ,gl5lair ! h\se 9 ,ed9burgh 0 reta9$ by ,mr4 ,maxwell1 & "h1 on ,june #ac1 #ahca1 0 born 8 only son1 ,james ,cl]k ,maxwell4 ,a daught]1 born e>li]1 di$ 9 infancy4 ,gl5lair1 h[ev]1 0 8 p>5ts' home1 & ne>ly all ! rem9isc5ces we h ( 8 *ildhood are connect$ ) x4 ,! laird devot$ himself to 8 e/ates & to ! education ( 8 son1 tak+1 h[ev]1 f "t to "t 8 full %>e 9 su* c\nty bus9ess z fell to him4 ,gl5lair 9 #ahcj 0 v mu* 9 ! wilds2 ! j\rney f ,ed9burgh occupi$ two days4 8,c>riages 9 ! mod]n s5se 7 h>dly kn[n to ! ,vale ( ,urr4 ,a sort ( d\ble gig ) a hood 0 ! be/ apology = a travell+ coa*1 & ! mo/ active mode ( locomotion 0 9 a k9d ( r\gh dog-c>t kn[n 9 ! family spee* z a hurly40#b ,mrs4 ,maxwell writes ?us#c1 :5 ! boy 0 ne>ly ?ree ye>s old1 to h] si/]1 ,miss ,jane ,cay3-- 8,he is a v happy man1 & has improv$ mu* s9ce ! wea!r got mod]ate4 ,he has great "w ) doors1 locks1 keys1 etc41 & #8,%[ me h[ x doos' is nev] out ( 8 m\?4 ,he also inve/igates ! hidd5 c\rse ( /reams & bell-wires--! way ! wat] gets f ! pond ?r\gh ! wall & a p5d or small bridge & d[n a dra9 into ,wat] ,orr1 !n pa/ ! smiddy & d[n to ! sea1 :]e ,maggy's %ips sail4 ,z to ! bells1 !y w n ru/2 he /&s s5try 9 ! kit*5 & ,mag runs ?r\gh ! h\se r++ !m all by turns1 or he r+s & s5ds ,bessy to see & %\t to let him "k2 & he drags papa all ov] to %[ him ! holes :]e ! wires g ?r\gh40 ,to discov] 8h[ x doos0 0 ?us e>ly 8 aim4 ,8 c\s91 ,mrs4 ,blackburn1 tells u t ?r\gh\t 8 *ildhood 8 con/ant "q 01 8,:at's ! g ( t8 ,:at does x d80 ,& if ! answ] 7 too vague or inconclusive1 he w\ld add1 8,b :at's ! p>ticul> g ( t80 ,pr(essor ,campbell's mo/ int]e/+ acc\nt ( ^! e>ly ye>s is illu/rat$ by a numb] ( sket*es ( episodes 9 8 life4 ,9 "o ,maxwell is absorb$ 9 wat*+ ! fiddl] at a c\ntry dance2 9 ano!r he is tea*+ 8 dog "s tricks2 9 a ?ird he is help+ a small] boy 9 8 ef=ts to build a ca/le4 ,toge!r ) 8 c\s91 ,miss ,w$d]burn1 he devis$ a numb] ( figures = a toy kn[n z a magic disc1 :i* aft]w>ds develop$ into ! zoetrope or :eel ( life1 & 9 :i*1 by means ( an +5i\s contrivance ( mirrors1 ! impression ( a cont9u\s movem5t 0 produc$4 ,?is happy life w5t on until 8 "m's dea? 9 ,decemb]1 #ahci2 %e di$1 at ! age ( =ty-eight1 ( ! pa9ful disease to :i* h] son aft]w>ds succumb$4 ,:5 ,james1 be+ !n eight ye>s old1 0 told t %e 0 n[ 9 heav51 he said3 8,oh1 ,i'm s glad6 ,n[ %e'll h no m pa940 ,aft] ?is 8 aunt1 ,miss ,jane ,cay1 took a "m's place4 ,! problem ( 8 education _h to be fac$1 & ! fir/ attempts 7 n successful4 ,a tutor _h be5 engag$ dur+ ,mrs4 ,maxwell's la/ illness1 & he1 x seems1 tri$ to co]ce ,cl]k ,maxwell into le>n+2 b su* treatm5t fail$1 & 9 #ahda1 :5 t5 ye>s old1 he began 8 s*ool-life at ! ,ed9burgh ,academy4 ,s*ool-life at fir/ _h its h>d%ips4 ,maxwell's appe>ance1 8 fir/ day at s*ool1 9 ,gall[ay home-spun & squ>e-to$ %oes ) buckles1 0 m ?an 8 fell[s c\ld /&4 8,:o made ^? %oes80 !y ask$#d2 & ! reply !y receiv$ 0-- 8,div ye k5 'twas a man1 ,& he liv$ 9 a h\se1 ,9 :ilk 0 a m\se40 ,he return$ to ,h]iot ,r[ t aft]noon1 says ,pr(essor ,campbell1 8) 8 tunic 9 rags & want+ ! skirt1 8 neat frill rumpl$ & torn--himself excessively amus$ by 8 exp]i5ces & %[+ n ! slighte/ sign ( irritation40 ,no4 #ca1 ,h]iot ,r[1 0 ! h\se ( 8 wid[$ aunt1 ,mrs4 ,w$d]burn1 ,mr4 ,maxwell's si/]2 & ?is1 ) occasional int]vals :5 he 0 ) ,miss ,cay1 0 8 home = ! next eight or n9e ye>s4 ,mr4 ,maxwell himself1 dur+ ?is p]iod1 sp5t mu* ( 8 "t 9 ,ed9burgh1 liv+ ) 8 si/] dur+ mo/ ( ! w9t] & return+ to ,gl5lair = ! spr+ & summ]4 ,mu* ( :at we "k ( ,cl]k ,maxwell's life dur+ ?is p]iod comes f ! lett]s :i* pass$ betwe5 him & 8 fa!r4 ,!y tell u ( ! close intimacy & affection :i* exi/$ betwe5 ! two1 ( ! boy's eag] desire to please & amuse 8 fa!r 9 ! dull solitude ( ,gl5lair1 & 8 fa!r's anxiety = 8 welf>e & progress4 ,pr(essor ,campbell 0 8 s*oolfell[1 & records ev5ts ( ^? ye>s 9 :i* he %>$1 :i* br+ cle>ly be=e u :at ,cl]k ,maxwell 0 l4 ,?us he writes#e3-- 8,he came to "k ,swift & ,dryd51 & aft] a :ile ,hobbes1 & ,butl]'s #8,hudibras4' ,!n1 if 8 fa!r 0 9 ,ed9burgh1 !y walk$ toge!r1 especially on ! ,saturday half-holiday1 & #8view$' ,lei? ,=t1 or ! prep>ations = ! ,granton railway1 or ! /ratification ( ,salisbury ,crags--always le>n+ some?+ new1 & w9n+ ideas = imag9ation to fe$ ^u4 ,"o ,saturday1 ,febru>y #ab1 #ahdb1 he _h a special treat1 be+ tak5 #8to see electro-magnetic ma*9es4'0 ,& aga91 speak+ ( 8 s*ool-life3-- 8,b at s*ool also he gradually made 8 way4 ,he soon discov]$ t ,lat9 0 wor? le>n+1 & ! ,greek ,delectus int]e/$ him :5 we got s f>4 ,& !re 7 two subjects 9 :i* he at once took ! =emo/ place1 :5 he _h a fair *ance ( do+ s2 ^! 7 ,scripture ,biography & ,engli%4 ,9 ari?metic z well z 9 ,lat9 8 comp>ative want ( read9ess kept him d[n4 8,on ! :ole he atta9$ a measure ( success :i* help$ to secure = him a c]ta9 respect2 &1 h[ev] /range he sometimes seem$ to 8 companions1 he _h ?ree qualities :i* !y c\ld n fail to und]/&--agile /r5g? ( limb1 imp]turbable c\rage1 & pr(\nd good-nature4 ,pr(essor ,james ,muirhead rememb]s him z #8a fri5dly boy1 ?\gh nev] q amalgamat+ ) ! re/4' ,& ano!r old class-fell[1 ! ,rev4 ,w4 ,macf>lane ( ,l5zie1 records ! foll[+ z 8 impression3--#8,cl]k ,maxwell1 :5 he ent]$ ! ,academy1 0 some:at ru/ic & some:at ecc5tric4 ,boys call$ him 8,dafty10 & us$ to try to make fun ( him4 ,on "o occasion ,i rememb] he turn$ ) trem5d\s vig\r1 ) a k9d ( demonic =ce1 on 8 torm5tors4 ,i ?9k he 0 let alone aft] t1 & gradually won ! respect ev5 ( ! mo/ ?\ghtless ( 8 s*oolfell[s4'0 ,! fir/ ref]5ce to ma!matical /udies occurs1 says ,pr(essor ,campbell1 9 a lett] to 8 fa!r writt5 soon aft] 8 ?irte5? bir?day4#f 8,aft] describ+ ! ,virg9ian ,m9/rels1 & betwixt inquiries aft] v>i\s pets at ,gl5lair1 he rem>ks1 z if x 7 an ord9>y piece ( news1 #8,i h made a tetrah$ron1 a dodecah$ron1 & two o!r h$rons1 ^: names ,i don't "k4' ,we _h n yet begun geometry1 & he _h c]ta9ly n at ?is "t le>nt ! def9itions 9 ,euclid2 yet he _h n m]ely realis$ ! nature ( ! five regul> solids suffici5tly to con/ruct !m out ( pa/ebo>d ) approximate accuracy1 b _h fur!r contriv$ o!r symmetrical polyh$ra d]iv$ f !m1 specim5s ( :i* 7z improv$ 9 #ahdh7 may be /ill se5 at ! ,cav5di% ,laboratory4 8,:o fir/ call$ 8 att5tion to ! pyramid1 cube1 etc41 ,i d n "k4 ,he may h se5 an acc\nt ( !m by *ance 9 a book4 ,b ! fact rema9s t at ?is e>ly "t 8 fancy1 l t ( ! old ,greek geomet]s1 0 arre/$ by ^! types ( complete symmetry2 & 8 imag9ation s ?or\ghly ma/]$ !m t he proce$$ to make !m ) 8 own h&4 ,t he himself atta*$ m importance to ?is mom5t ?an ! lett] indicates is prov$ by ! c>e ) :i* he has pres]v$ ^! p]i%able ?+s1 s t !y 7or ^? :i* replac$ !m 9 #ahdh7 are /ill 9 exi/5ce aft] ?irty-sev5 ye>s40 ,! summ] holidays 7 sp5t at ,gl5lair4 ,8 c\s91 ,miss ,jemima ,w$d]burn1 0 ) him1 & %>$ 8 play4 ,h] skill$ p5cil has left u _m amus+ pictures ( ! "t1 "s ( :i* are reproduc$ by ,pr(essor ,campbell4 ,!re 7 exp$itions & picnics ( all sorts1 & a new toy kn[n z 8! devil on two /icks0 af=d$ inf9ite amusem5t4 ,! w9t] holidays usually f\nd him at ,p5icuik1 or occasionally at ,glasg[1 ) ,pr(essor ,blackburne or ,pr(essor ,w4 ,?omson 7n[ ,"l ,kelv974 ,9 ,octob]1 #ahdd1 ,maxwell 0 promot$ to ! rector's class-room4 ,john ,williams1 aft]w>ds ,ar*deacon ( ,c>digan1 a di/+ui%$ ,baliol man1 0 rector1 & ! *ange 0 9 _m ways an important "o = ,maxwell4 ,he writes to 8 fa!r3 8,i l ,p---- bett] ?an ,b----4 ,we h lots ( jokes1 & he speaks a great deal1 & we h n s mu* monoton\s p>s+4 ,9 ! ,engli% ,milton is bett] ?an ! ,hi/ory ( ,greece44440 ,p---- 0 ! boys' nickname = ! rector2 ,b---- = ,mr4 ,c>mi*ael1 ! second ma/]4 ,?is#g is ! acc\nt ( ,maxwell's fir/ int]view ) ! rector3-- ,rector3 8,:at "p ( ,gall[ay d y come f80 ,j4 ,c4 ,m43 8,f ! ,vale ( ,urr4 ,ye spell x o1 err1 err1 or oo1 err1 err40 ,! /udy ( geometry 0 begun1 & 9 ! ma!matical ma/]1 ,mr4 ,gloag1 ,maxwell f\nd a tea*] ) a real gift = 8 task4 ,x 0 "h t ,maxwell's va/ sup]iority to _m :o 7 8 companions at once %[$ itself4 8,he seem$10 says ,pr(essor ,campbell1 8to be 9 ! he>t ( ! subject :5 !y 7 only at ! b\nd>y2 b ! boyi% game ( conte/+ po9t by po9t ) su* a m9d 0 a mo/ :olesome /imulus1 s t ! m]e ex]cise ( faculty 0 a pure joy4 ,) ,maxwell ! fir/ lessons ( geometry bran*$ out at once into inquiries :i* became fruitful40 ,9 ,july1 #ahde1 he writes3-- 8,i h got ! #aa? prize = ,s*ol>%ip1 ! #a/ = ,engli%1 ! prize = ,engli% v]ses1 & ! ,ma!matical ,m$al4 ,i tri$ = ,scripture k1 & ,hamilton 9 ! #g? has got x4 ,we tri$ = ! ,m$al on ,?ursday4 ,i _h done !m all1 & got home at half-pa/ two2 b ,campbell /ay$ till f\r4 ,i 0 r tir$ ) writ+ ex]cises f n9e till half-pa/ two4 8,campbell & ,i w5t #8once m unto ! b7r7ea*' to-day at ,portobello4 ,i c swim a little n[4 ,campbell has got #f prizes4 ,he got a lett] writt5 too soon1 congratulat+ him ^u my m$al2 b !re is no rivalry betwixt u1 z ,b---- ,c>mi*ael says40 ,aft] a summ] sp5t *iefly at ,gl5lair1 he return$ ) 8 fa!r to ,ed9burgh = ! w9t]1 & began1 at ! age ( f\rte51 to g to ! meet+s ( ! ,royal ,society ( ,ed9burgh4 ,at ! ,society ( ,arts he met ,mr4 ,r4 ,d4 ,hay1 ! decorative pa9t]1 :o _h int]e/$ himself 9 ! attempt to r$uce beauty 9 =m & col\r to ma!matical pr9ciples4 ,cl]k ,maxwell 0 int]e/$ 9 ! "q h[ to draw a p]fect oval1 & devis$ a me?od ( draw+ oval curves :i* 0 ref]r$ by 8 fa!r to ,pr(essor ,=bes = 8 criticism & sugge/ions4 ,aft] discuss+ ! matt] ) ,pr(essor ,kell&1 ,pr(essor ,=bes wrote z foll[s#h3-- 8,,my ,,de> ,,sir1--,i am glad to f9d to-day1 f ,pr(essor ,kell&1 t 8 op9ion ( y\r son's pap] agrees ) m9e1 namely1 t x is mo/ +5i\s1 mo/ cr$itable to him1 &1 we believe1 a new way ( consid]+ high] curves ) ref]5ce to foci4 ,un=tunately1 ^! ovals appe> to be curves ( a v high & intractable ord]1 s t possibly ! elegant me?od ( description may n lead to a correspond+ simplicity 9 inve/igat+ _! prop]ties4 ,b t is n ! pres5t po9t4 ,if y wi% x1 ,i ?9k t ! simplicity & elegance ( ! me?od w\ld entitle x to be br\ght be=e ! ,royal ,society4--,believe me1 my de> sir1 y\rs truly1 8,,james ,d4 ,,=bes40 ,9 consequ5ce ( ?is1 ,cl]k ,maxwell's fir/ publi%$ pap] 0 communicat$ to ! ,royal ,society ( ,ed9burgh on ,april #f?1 #ahdf1 :5 its au?or 0 b>ely fifte54 ,its title is z foll[s3 8,on ! ,description ( ,oval ,curves & ^? hav+ a ,plurality ( ,foci4 ,by ,mr4 ,cl]k ,maxwell1 ,junior4 ,) ,rem>ks by ,pr(essor ,=bes4 ,communicat$ by ,pr(essor ,=bes40 ,! notice 9 8 fa!r's di>y runs3 8,m4 #f ,ap41 #ahdf4 ,royal ,society ) ,jas4 ,pr(essor ,=bes gave acct4 ( ,james's ,ovals4 ,met ) v great att5tion & approbation g5]ally40 ,?is 0 ! beg9n+ ( ! lifelong fri5d%ip betwe5 ,maxwell & ,=bes4 ,! curves inve/igat$ by ,maxwell h ! prop]ty t ! sum f\nd by add+ to ! di/ance ( any po9t on ! curve f "o focus a con/ant multiple ( ! di/ance ( ! same po9t f a second focus is always con/ant4 ,! curves are ( great importance 9 ! !ory ( light1 = if ?is con/ant factor expresses ! refractive index ( any m$ium1 !n light div]g+ f "o focus )\t ! m$ium & refract$ at a surface b\nd+ ! m$ium1 & hav+ ! =m ( "o ( ,maxwell's ovals1 w be refract$ s z to conv]ge to ! second focus4 ,ab\t ! same "t he 0 busy ) "s inve/igations on ! prop]ties ( jelly & gutta-p]*a1 :i* seem to h be5 sugge/$ by ,=bes' 8,!ory ( ,glaci]s40 ,he fail$ to obta9 ! ,ma!matical ,m$al 9 #ahdf--possibly on acc\nt ( ^! rese>*es--b he cont9u$ at s*ool till #ahdg1 :5 he left1 be+ !n fir/ 9 ma!matics & 9 ,engli%1 & ne>ly fir/ 9 ,lat94 ,9 #ahdg he 0 work+ at magnetism & ! pol>isation ( light4 ,"s "t 9 t ye> he 0 tak5 by 8 uncle1 ,mr4 ,john ,cay1 to see ,william ,nicol1 ! inv5tor ( ! pol>is+ prism1 :o %[$ him ! col\rs exhibit$ by pol>is$ light aft] pass+ ?r\gh unanneal$ glass4 ,on 8 return1 he made a pol>iscope ) a glass reflector4 ,! framework ( ! fir/ in/rum5t 0 ( c>dbo>d1 b a sup]ior article 0 aft]w>ds con/ruct$ ( wood4 ,small l5ses m\nt$ on c>dbo>d 7 employ$ :5 a conical p5cil 0 ne$$4 ,by means ( ?is in/rum5t he exam9$ ! figures exhibit$ by pieces ( unanneal$ glass1 :i* he prep>$ himself2 &1 ) a cam]a lucida & box ( col\rs1 he reproduc$ ^! figures on pap]1 tak+ c>e to sket* no outl9es1 b to %ade ea* col\r$ b& imp]ceptibly into ! next4 ,"s ( ^! col\r$ draw+s he =w>d$ to ,nicol1 & 0 m ?an repaid by ! receipt %ortly aft]w>ds ( a pair ( prisms prep>$ by ,nicol himself4 ,^! prisms 7 always v highly priz$ by ,maxwell4 ,once1 :5 at ,tr9ity1 ! little box conta9+ !m 0 c>ri$ (f by 8 b$-mak] dur+ a vacation1 & de/9$ = de/ruction4 ,! b$-mak] di$ be=e t]m comm5c$1 & x 0 only by dilig5t se>* among h] effects t ! prisms 7 recov]$4#i ,aft] ?is !y 7 m c>efully gu>d$1 & !y are n[1 toge!r ) ! wood5 pol>iscope1 ! bits ( unanneal$ glass1 & ! wat]-col\r draw+s1 9 "o ( ! %[cases at ! ,cav5di% ,laboratory4 ,ab\t ?is "t1 ,pr(essor ,p4 ,g4 ,tait & he 7 s*oolfell[s at ! ,academy1 ackn[l$g$ z ! two be/ ma!maticians 9 ! s*ool4 ,x 0 ?\ght desirable1 says ,pr(essor ,campbell1 t 8we %\ld h lessons 9 physical sci5ce1 s "o ( ! classical ma/]s gave !m out ( a text-book4444 ,! only ?+ ,i di/9ctly rememb] ab\t ^! h\rs is t ,maxwell & ,p4 ,g4 ,tait seem$ to "k mu* m ab\t ! subject ?an our tea*] did40 ,an int]e/+ acc\nt ( ^! days is giv5 by ,pr(essor ,tait 9 an obitu>y notice on ,maxwell pr9t$ 9 ! 8,proce$+s ( ! ,royal ,society ( ,ed9burgh1 #ahgi-hj10 f :i* ! foll[+ is tak53-- 8,:5 ,i fir/ made ,cl]k ,maxwell's acqua9tance1 ab\t ?irty-five ye>s ago1 at ! ,ed9burgh ,academy1 he 0 a ye> be=e me1 be+ 9 ! fif? class1 :ile ,i 0 9 ! f\r?4 8,at s*ool he 0 at fir/ reg>d$ z %y & r dull4 ,he made no fri5d%ips1 & he sp5t 8 occasional holidays 9 read+ old ballads1 draw+ curi\s diagrams1 & mak+ rude me*anical models4 ,?is absorption 9 su* pursuits1 totally un9telligible to 8 s*oolfell[s 7:o 7 !n q innoc5t ( ma!matics71 ( c\rse procur$ him a n v complim5t>y nickname1 :i* ,i "k is /ill rememb]$ by _m ,fell[s ( ?is ,society4 ,ab\t ! middle ( 8 s*ool c>e]1 h[ev]1 he surpris$ 8 companions by sudd5ly becom+ "o ( ! mo/ brilliant among !m1 ga9+ high1 & sometimes ! highe/1 prizes = s*ol>%ips1 ma!matics1 & ,engli% v]se composition4 ,f ?is "t =w>d ,i became v intimate ) him1 & we discuss$ toge!r1 ) s*oolboy en?usiasm1 num]\s curi\s problems1 among :i* ,i rememb] p>ticul>ly ! v>i\s plane sections ( a r+ or tore1 & ! =m ( a cyl9drical mirror :i* %\ld %[ "o 8 own image unp]v]t$4 ,i /ill possess "s ( ! ,,mss4 we ex*ang$ 9 #ahdf & e>ly 9 #ahdg4 ,^? by ,maxwell are on #8,! ,conical ,p5dulum1' #8,desc>tes' ,ovals1' #8,meloid & ,apioid1' & #8,trifocal ,curves4' ,all are drawn up 9 /rict geometrical =m & divid$ into consecutive propositions4 ,! ?ree latt] are connect$ ) 8 fir/ publi%$ pap]1 communicat$ by ,=bes to ?is society & pr9t$ 9 our #8,proce$+s1' vol4 ii41 "u ! title1 #8,on ! ,description ( ,oval ,curves & ^? hav+ a ,plurality ( ,foci' 7#ahdf74 ,at ! "t :5 ^! pap]s 7 writt5 he _h receiv$ no in/ruction 9 ma!matics beyond a few books ( ,euclid & ! m]e/ elem5ts ( algebra40 ,9 ,novemb]1 #ahdg1 ,cl]k ,maxwell ent]$ ! ,univ]sity ( ,ed9burgh1 le>n+ ma!matics f ,kell&1 natural philosophy f ,j4 ,d4 ,=bes1 & logic f ,sir ,w4 ,r4 ,hamilton4 ,at ?is "t1 accord+ to ,pr(essor ,campbell#aj-- 8he /ill occasion$ "s conc]n to ! m conv5tional among/ 8 fri5ds by ! orig9ality & simplicity ( 8 ways4 ,8 replies 9 ord9>y conv]sation 7 indirect & enigmatical1 (t5 utt]$ ) hesitation & 9 a monoton\s key4 ,:ile extremely neat 9 8 p]son1 he _h a root$ objection to ! vanities ( />* & gloves4 ,he _h a pi\s horror ( de/roy+ any?+1 ev5 a scrap ( writ+-pap]4 ,he pref]r$ travell+ by ! ?ird class 9 railway j\rneys1 say+ he lik$ a h>d seat4 ,:5 at table he (t5 seem$ ab/ract$ f :at 0 go+ on1 be+ absorb$ 9 obs]v+ ! effects ( refract$ light 9 ! f+]-glasses1 or 9 try+ "s exp]im5t ) 8 eyes--see+ r\nd a corn]1 mak+ invisible /]eoscopes1 & ! l4 ,miss ,cay us$ to call 8 att5tion by cry+1 #8,jamsie1 y're 9 a prop4' ,he nev] ta/$ w9e2 & he spoke to g5tle & simple 9 exactly ! same tone4 ,on ! o!r h&1 8 tea*]s--,=bes above all--_h =m$ ! highe/ op9ion ( 8 intellectual orig9ality & =ce2 & a few exp]i5c$ obs]v]s1 9 wat*+ 8 devotion to 8 fa!r1 began to h "s inkl+ ( 8 h]oic s+l5ess ( he>t4 ,to 8 college companions1 :om he c\ld n[ select at w1 8 qua9t hum\r 0 an endless delight4 ,8 *ief associates1 aft] ,i w5t to ! ,univ]sity ( ,glasg[1 7 my bro!r1 ,rob]t ,campbell 7/ill at ! ,academy71 ,p4 ,g4 ,tait1 & ,allan ,/ew>t4 ,tait w5t to ,pet]h\se1 ,cambridge1 9 #ahdh1 aft] "o session ( ! ,univ]sity ( ,ed9burgh2 ,/ew>t to ! same college 9 #ahdi2 ,maxwell did n g up until #ahej40 ,dur+ ?is p]iod he wrote two important pap]s4 ,! "o1 on 8,roll+ ,curves10 0 read to ! ,royal ,society ( ,ed9burgh by ,pr(essor ,kell&--78x 0 n ?\ght prop] = a boy 9 a r\nd jacket to m\nt ! ro/rum07--9 ,febru>y1 #ahdi2 ! o!r1 on 8,! ,equilibrium ( ,ela/ic ,solids10 appe>$ 9 ! spr+ ( #ahej4 ,! vacations 7 sp5t at ,gl5lair1 & we le>n f lett]s to ,pr(essor ,campbell & o!rs h[ ! "t 0 pass$4 8,on ,saturday10 he writes#aa--;,april #bf?1 #ahdh1 j aft] 8 arrival home--8! natural philosoph]s ran up ,ar?ur's ,seat ) ! b>omet]4 ,! ,pr(essor set x d[n at ! top4444 ,he did n set x /raight1 & made ! hill gr[ fifty feet2 b we got x d[n aga940 ,9 a lett] ( ,july 9 ! same ye> he describes 8 laboratory3-- 8,i h regul>ly set up %op n[ above ! wa%-h\se at ! gate1 9 a g>ret4 ,i h an old door set on two b>rels1 & two *airs1 ( :i* "o is safe1 & a skylight above :i* w slide up & d[n4 8,on ! door 7or table7 !re is a lot ( b[ls1 jugs1 plates1 jam pigs1 etc41 conta9+ wat]1 salt1 soda1 sulphuric acid1 blue vitriol1 plumbago ore2 also brok5 glass1 iron1 & copp] wire1 copp] & z9c plate1 bees' wax1 seal+ wax1 clay1 ros91 *>coal1 a l5s1 a ,smee's galvanic app>atus1 & a c\ntless v>iety ( little beetles1 spid]s1 & wood lice1 :i* fall into ! diff]5t liquids & poison !mselves4 ,i int5d to get up "s m galvanism 9 jam pigs2 b ,i mu/ fir/ copp] ! int]iors ( ! pigs1 s ,i am exp]im5t+ on ! be/ me?ods ( electrotyp+4 ,s ,i am mak+ copp] seals ) ! device ( a beetle4 ,fir/1 ,i ?\ght a beetle 0 a good conductor1 s ,i emb$d$ "o 9 wax 7n at all cruel1 because ,i slew him 9 boil+ wat]1 9 :i* he nev] kick$71 leav+ 8 back out2 b he w\ld n d4 ,!n ,i took a ca/ ( him 9 seal+ wax1 & press$ wax into ! holl[1 & blacklead$ x ) a bru%2 b nei!r w\ld t d4 ,s at la/ ,i took my f+]s & rubb$ x1 :i* ,i f9d ! be/ way to use ! blacklead4 ,!n x copp]$ fam\sly4 ,i melt out ! wax ) ! l5s1 t be+ ! cleane/ way ( gett+ a /rong heat1 s ,i d mo/ ?+s ) x t ne$ heat4 ,to-day ,i a/oni%$ ! natives z foll[s4 ,i took a cry/al ( blue vitriol & put ! l5s to x1 & s drove (f ! wat]1 leav+ a :ite p[d]4 ,!n ,i did ! same to "s wa%+ soda1 & mix$ ! two :ite p[d]s toge!r1 & made a small native spit on !m1 :i* turn$ !m gre5 by a mutual ex*ange1 ?us3--#a4 ,sulphate ( copp] & c>bonate ( soda4 #b4 ,sulphate ( soda & c>bonate ( copp] 7blue or gre5740 ,( 8 read+ he says3--8,i am read+ ,h]odotus' #8,eut]pe1' hav+ tak5 ! turn--t is to say t sometimes ,i c d props41 read ,diff4 & ,int4 ,calc41 ,poisson1 ,hamilton's diss]tation1 etc40 ,9 ,septemb] he 0 busy ) pol>is$ light4 8,we 7 at ,ca/le ,d\glas ye/]day1 & got cry/als ( saltpetre1 :i* ,i h be5 cutt+ up into plates to-day 9 hopes to see r+s40 ,9 ,july1 #ahdi1 he writes#ab3-- 8,i h set up ! ma*9e = %[+ ! r+s 9 cry/als1 :i* ,i plann$ dur+ y\r visit la/ ye>4 ,x answ]s v well4 ,i also made "s exp]im5ts on compress$ jellies 9 illu/ration ( my props4 on t subject4 ,! pr9cipal "o 0 ?is3--,! jelly is p\r$ :ile hot into ! annul> space conta9$ betwe5 a pap] cyl9d] & a cork2 !n1 :5 cold1 ! cork is twi/$ r\nd & ! jelly expos$ to pol>is$ light1 :5 a transv]se cross1 ,x1 n 1 appe>s1 ) r+s z ! inv]se squ>e ( ! radius1 all :i* is fully v]ifi$4 ,hip6 etc4 ,q4,e4,d40 ,& aga9 on ,m>* #bbnd1 #ahej3-- 8,at ,practical ,me*anics ,i h be5 turn+ ,devils ( sorts4 ,= private /udies ,i h be5 read+ ,"y's #8,lectures1' ,willis's #8,pr9ciples ( ,me*anism1' ,moseley's #8,eng9e]+ & ,me*anics1' ,dixon on #8,heat1' & ,moigno's #8,rp]toire d',optique4' ,?is la/ is a v complete analysis ( all t has be5 done 9 ! optical way f ,fresnel to ! end ( #ahdi1 & !re is ano!r volume a-com+ :i* w complete ! "w4 ,!re is 9 x1 besides common optics1 all ab\t ! o!r ?+s :i* accompany light1 z heat1 *emical action1 photographic rays1 action on vegetables1 etc4 8,my notions are r few1 z ,i d n ent]ta9 !m j n[4 ,i h a notion = ! torsion ( wires & rods1 n to be made till ! vacation2 ( exp]im5ts on ! action ( compression on glass1 jelly1 etc41 num]ically done up2 ( pap]s = ! ,physico-,ma!matical ,society 7:i* is to revive 9 e>ne/ next session672 on ! relations ( optical & me*anical con/ants1 _! desirabl5ess1 etc42 & susp5sion bridges1 & cat5>ies1 & ela/ic curves4 ,alex4 ,campbell1 ,agnew1 & ,i are appo9t$ to read up ! subject ( p]iodical %oot+ />s1 & to prep>e a li/ ( ! ph5om5a to be obs]v$ on ! #i? ,augu/ & #ac? ,novemb]4 ,! society's b>omet] is to be tak5 up ,ar?ur's ,seat at ! end ( ! session1 :5 ,=bes goes up1 & ,all /ud5ts are invit$ to att5d1 s t ! exi/5ce ( ! society may be recognis$40 ,x 0 at la/ settl$ t he 0 to g up to ,cambridge4 ,tait _h be5 at ,pet]h\se = two ye>s1 :ile ,allan ,/ew>t _h jo9$ him !re 9 #ahdi1 & aft] mu* discussion x 0 arrang$ t ,maxwell %\ld ent] at ! same college4 ,( ?is p]iod ( 8 life ,tait writes z foll[s3-- 8,! w9t] ( #ahdg f\nd u toge!r 9 ! classes ( ,=bes & ,kell&1 :]e he highly di/+ui%$ himself4 ,) ! =m] he 0 a p>ticul> fav\rite1 be+ admitt$ to ! free use ( ! class app>atus = orig9al exp]im5ts4 ,he l+]$ "h beh9d mo/ ( 8 =m] associates1 hav+ sp5t ?ree ye>s at ! ,univ]sity ( ,ed9burgh1 work+ 7)\t any assi/ance or sup]vision7 ) physical & *emical app>atus1 & dev\r+ all sorts ( sci5tific works 9 ! libr>y4 ,dur+ ?is p]iod he wrote two valuable pap]s1 :i* are publi%$ 9 our #8,transactions1' on #8,! ,!ory ( ,roll+ ,curves' & on #8,! ,equilibrium ( ,ela/ic ,solids4' ,?us he br\ght to ,cambridge1 9 ! autumn ( #ahej1 a mass ( k :i* 0 really imm5se = s "y a man1 b 9 a /ate ( disord] appall+ to 8 me?odical private tutor4 ,?\gh t tutor 0 ,william ,hopk9s1 ! pupil to a great ext5t took 8 own way1 & x may safely be said t no high wrangl] ( rec5t ye>s ev] ent]$ ! ,s5ate ,h\se m imp]fectly tra9$ to produce #8pay+' "w ?an did ,cl]k ,maxwell4 ,b by %e] /r5g? ( intellect1 ?\gh ) ! v m9imum ( k h[ to use x to advantage "u ! conditions ( ! exam9ation1 he obta9$ ! position ( ,second ,wrangl]1 & 0 bracket$ equal ) ! ,s5ior ,wrangl] 9 ! high] ordeal ( ! ,smi?'s ,prizes4 ,8 "n appe>s 9 ! ,cambridge #8,cal5d>' z ,maxwell ( ,tr9ity1 b he 0 orig9ally ent]$ at ,pet]h\se1 & kept 8 fir/ t]m !re1 9 t small b mo/ anci5t f\ndation :i* has ( late furni%$ ,scotl& ) ! majority ( ! pr(essors ( ma!matics & natural philosophy 9 h] f\r univ]sities40 ,:ile ,w4 ,d4 ,niv51 9 8 preface to ,maxwell's collect$ works 7p4 xii471 says3-- 8,x may readily be suppos$ t 8 prep>atory tra9+ = ! ,cambridge c\rse 0 f> remov$ f ! ord9>y type4 ,!re _h inde$ = "s "t be5 practically no re/ra9t ^u 8 plan ( /udy1 & 8 m9d _h be5 all[$ to foll[ its natural b5t t[>ds sci5ce1 ?\gh n to an ext5t s absorb+ z to )draw him f o!r pursuits4 ,?\gh he 0 n a sportsman--inde$1 sport s-call$ 0 always repugnant to him--he 0 yet exce$+ly fond ( a c\ntry life4 ,he 0 a good horseman & a good swimm]4 ,:5ce1 h[ev]1 he d]iv$ 8 *ief enjoym5t may be ga!r$ f ! acc\nt :i* ,mr4 ,campbell gives ( ! ze/ ) :i* he quot$ on "o occasion ! l9es ( ,burns :i* describe ! poet f9d+ inspiration :ile w&]+ along ! banks ( a /ream 9 ! free indulg5ce ( 8 fancies4 ,maxwell 0 n only a lov] ( poetry1 b himself a poet1 z ! f9e pieces ga!r$ toge!r by ,mr4 ,campbell abundantly te/ify4 ,he saw1 h[ev]1 t 8 true call+ 0 sci5ce1 & nev] reg>d$ ^! poetical ef=ts z o!r ?an m]e pa/ime4 ,devotion to sci5ce1 already /imulat$ by successful endeav\r2 a t5d5cy to pond] ov] philosophical problems2 & an atta*m5t to ,engli% lit]ature1 p>ticul>ly to ,engli% poetry--^! ta/es1 implant$ 9 a m9d ( s+ul> /r5g? & purity1 may be said to h be5 ! end[m5ts ) :i* "y ,maxwell began 8 ,cambridge c>e]4 ,besides ?is1 8 sci5tific read+1 z we may ga!r f 8 pap]s to ! ,royal ,society ( ,ed9burgh ref]r$ to above1 0 already ext5sive & v>i$4 ,he br\ght ) him1 says ,pr(essor ,tait1 a mass ( k :i* 0 really imm5se = s "y a man1 b 9 a /ate ( disord] appall+ to 8 me?odical private tutor40 ,,*apt] ,,ii4 ,,und]graduate ,,life ,,at ,,cambridge4 ,maxwell did n rema9 long at ,pet]h\se2 be=e ! end ( 8 fir/ t]m he migrat$ to ,tr9ity1 & 0 ent]$ "u ,dr4 ,?ompson ,decemb] #ad?1 #ahej4 ,he appe>$ to ! tutor a %y & diffid5t y\?1 b pres5tly surpris$ ,dr4 ,?ompson by produc+ a bundle ( pap]s--copies1 probably1 ( ^? he _h already publi%$--& rem>k+1 8,p]haps ^! may %[ t ,i am n unfit to ent] at y\r ,college40 ,! *ange 0 press$ ^u him by _m fri5ds1 ! gr\nds ( ! advice be+ t1 f ! l>ge numb] ( high wrangl]s rec5tly at ,pet]h\se & ! smallness ( ! f\ndation1 ! *ances ( a ,fell[%ip !re = a ma!matical man 7 less ?an at ,tr9ity4 ,x 0 a /ep he nev] regrett$2 ! prospect ( a ,fell[%ip _h b little influ5ce on 8 m9d4 ,he f\nd1 h[ev]1 at ! l>g] college ampl] opportunities = self-improvem5t1 & x 0 possible = him to select 8 fri5ds f among m5 :om he o!rwise w\ld nev] h kn[n4 ,! record ( 8 und]graduate life is n v full2 8 lett]s to 8 fa!r h1 un=tunately1 be5 lo/1 b we h en\gh 9 ! recollections ( fri5ds /ill liv+ to picture :at x 0 l4 ,at fir/ he lodg$ 9 ,k+'s ,p>ade ) an old ,ed9burgh s*oolfell[1 ,c4 ,h4 ,rob]tson4 ,he att5d$ ! ,college lectures on ma!matics1 ?\gh !y 7 some:at elem5t>y1 & work$ z a private pupil ) ,port]1 ( ,pet]h\se4 ,8 fa!r writes to him1 ,novemb]1 #ahej3 8,h y call$ on ,pr(essors ,s$gwick1 at ,tr941 & ,/okes1 at ,pembroke8 ,if n1 y %\ld d bo?4 ,/okes w be mo/ 9 y\r l9e1 if he takes y 9 h& at all4 ,s$gwick is also a great ,don 9 8 l9e1 &1 if y 7 ent]$ 9 geology1 w\ld be a mo/ valuable acqua9tance40 ,9 8 second ye> he became a pupil ( ,hopk9s1 ! great coa*2 he also att5d$ ,/okes' lectures1 & ! fri5d%ip :i* la/$ till 8 dea? 0 ?us begun4 ,9 ,april1 #aheb1 he 0 elect$ a s*ol>1 & obta9$ rooms 9 ,college 7,g1 ,old ,c\rt74 ,9 ,june1 #aheb1 he came ( age4 8,i tru/ y w be z discreet :5 major z y h be5 :ile m9or10 writes 8 fa!r ! day be=e4 ,! next academic ye>1 ,octob]1 #aheb1 to ,june1 #ahec1 0 a v busy "o2 h>d gr9d = ! ,tripos occupi$ 8 "t1 & he seems to h be5 ?or\ghly ov]/ra9$4 ,he 0 tak5 ill :ile /ay+ ne> ,l[e/(t ) ! ,rev4 ,c4 ,b4 ,tayl]1 ! uncle ( a ,college fri5d4 ,8 own acc\nt ( ! illness is giv5 9 a lett] to ,pr(essor ,campbell#ac1 dat$ ,july #ad?1 #ahec4 8,y wrote j 9 "t = y\r lett] to rea* me z ,i rea*$ ,cambridge4 ,aft] exam9ation1 ,i w5t to visit ! ,rev4 ,c4 ,b4 ,tayl] 7uncle to a ,tayl] :om ,i ?9k y h se5 "u ! "n ( ,fre%man1 etc41 & au?or ( _m tracts & o!r didactic works74 ,we _h little exp$ites & walks1 & ?+s p>o*ial & educational1 & dome/icity4 ,i int5d$ to return on ! #ah? ,june1 b on ! #ag? ,i felt unwell1 & took measures accord+ly to be well aga9--i4e4 w5t to b$1 & made up my m9d to recov]4 ,b x la/$ m ?an a =tnight1 dur+ :i* "t ,i 0 tak5 c>e ( beyond expectation 7n t ,i did n expect mu* be=e74 ,:5 ,i 0 p]fectly useless & c\ld n sit up )\t fa9t+1 ,mr4 ,tayl] did ev]y?+ = me 9 su* a way t ,i _h no fe> ( giv+ tr\ble4 ,s did ,mrs4 ,tayl]2 & ! two nephews did all !y c\ld4 ,s !y kept me 9 great happ9ess all ! "t1 & deta9$ me till ,i 0 able to walk ab\t & got back /r5g?4 ,i return$ on ! #d? ,july4 8,! consequ5ce ( all ?is is t ,i correspond ) ,mr4 ,tayl]1 & h ent]$ into bonds ) ! nephews1 ( all ( :om m h]eaft]4 ,s9ce ,i came "h ,i h be5 att5d+ ,hop41 b1 ) 8 approval1 did n beg9 full sw+4 ,i am gett+ on1 ?\gh1 & ! "w is n gr9d+ on ! prep>$ bra940 ,dur+ ?is p]iod he wrote "s pap]s = ! ,cambridge & ,dubl9 ,ma!matical ,j\rnal :i* w be ref]r$ to aga9 lat]4 ,he 0 also a memb] ( a discussion society kn[n z ! 8,apo/les10 & "s ( ! essays contribut$ by him are pres]v$ by ,pr(essor ,campbell4 ,mr4 ,niv51 9 8 preface to ! collect$ edition ( ,maxwell's works1 sugge/s t ! composition ( ^! essays laid ! f\ndation ( t lit]>y f9i% :i* is "o ( ! *>act]i/ics ( ,maxwell's sci5tific writ+s4 ,among 8 fri5ds at ! "t 7 ,tait1 ,*>les ,mack5zie ( ,caius1 ! mission>y bi%op ( ,c5tral ,africa1 ,h5ry & ,frank ,mack5zie ( ,tr9ity1 ,droop1 ?ird ,wrangl] 9 #ahed2 ,g$ge1 ,isaac ,taylor1 ,blaki/on1 ,f4 ,w4 ,f>r>1#ad ,h4 ,m4 ,butl]1#ae ,hort1 ,v4 ,lu%+ton1 ,cecil ,munro1 ,g4 ,w4 ,h4 ,tayl]1 & ,w4 ,n4 ,lawson4 ,"s ( ^! :o surviv$ him h giv5 to ,pr(essor ,campbell _! recollections ( ^! und]graduate days1 :i* are full ( int]e/4 ,?us ,mr4 ,lawson writes#af3-- 8,!re mu/ be _m ( 8 qua9t v]ses ab\t1 if "o c\ld lay h&s on !m1 = ,maxwell 0 con/antly produc+ some?+ ( ! sort & br++ x r\nd to 8 fri5ds1 ) a sly *uckle at ! hum\r1 :i*1 ?\gh 8 own1 no "o enjoy$ m ?an himself4 8,i rememb] ,maxwell com+ to me "o morn+ ) a copy ( v]ses beg9n+1 #8,g9 a body meet a body go+ ?r\gh ! air1' 9 :i* he _h twi/$ ! well-kn[n song into a description ( ! laws ( impact ( solid bodies4 8,!re 0 also a description :i* ,maxwell wrote ( "s ,univ]sity c]emony--,i =get :at--9 :i* somebody #8w5t be=e' & somebody #8foll[$ aft]1' & #89 ! mid/ 7 ! wrangl]s1 play+ ) ! symbols4' 8,^! la/ words1 h[ev] meant1 71 9 fact1 a description ( 8 own wond]ful p[]4 ,i rememb]1 "o day 9 lecture1 our lectur] _h fill$ ! black-bo>d ?ree times ) ! inve/igation ( "s h>d problem 9 ,geometry ( ,?ree ,dim5sions1 & 0 n at ! end ( x1 :5 ,maxwell came up ) a "q :e!r x w\ld n come out geometrically1 & %[$ h[1 ) a figure1 & 9 a few l9es1 !re 0 ! solution at once4 8,maxwell 01 ,i d>esay y rememb]1 v fond ( a talk ^u almo/ any?+4 ,he & ,i 7 pupils 7at an enorm\s di/ance ap>t7 ( ,hopk9s1 & ,i well recollect h[1 :5 ,i _h be5 work+ ! night be=e & all ! morn+ at ,hopk9s's problems1 ) little or no result1 ,maxwell w\ld come 9 = a gossip1 & talk on :ile ,i 0 wi%+ him f> away1 till at la/1 ab\t half an h\r or s be=e our meet+ at ,hopk9s's1 he w\ld say1 #8,well1 ,i mu/ g to old ,hop4's problems'2 &1 by ! "t we met !re1 !y 7 all done4 8,i rememb] ,hopk9s tell+ me1 :5 speak+ ( ,maxwell1 ei!r j be=e or j aft] 8 degree1 #8,x is n possible = t man to ?9k incorrectly on physical subjects'2 & ,hopk9s1 z y "k1 _h _h1 p]haps1 m exp]i5ce ( ma!matical m9ds ?an any man ( 8 "t40 ,! la/ clause is "p ( a quotation f a di>y kept by ,mr4 ,lawson at ,cambridge1 9 :i*1 "u ! date ,july #ae?1 #ahec1 he writes3-- 8,he 7,hopk9s7 0 talk+ to me ?is ev5+ ab\t ,maxwell4 ,he says he is unque/ionably ! mo/ extraord9>y man he has met ) 9 ! :ole range ( 8 exp]i5ce2 he says x appe>s impossible = ,maxwell to ?9k incorrectly on physical subjects2 t 9 8 analysis1 h[ev]1 he is f> m defici5t4 ,he looks ^u him z a great g5ius ) all its ecc5tricities1 & prophesies t "o day he w %9e z a light 9 physical sci5ce--a prophecy 9 :i* all 8 fell[-/ud5ts /r5u\sly unite40 ,h[ _m :o h /ruggl$ ?r\gh ! 8,electricity & ,magnetism0 h realis$ ! tru? ( ! rem>k ab\t ! correctness ( 8 physical intuitions & ! defici5cy at times ( 8 analysis6 ,dr4 ,butl]1 a fri5d ( ^! e>ly days1 prea*$ ! ,univ]sity s]mon on ,novemb] #af?1 #ahgi1 t5 days aft] ,maxwell's dea?1 & spoke ?us3-- 8,x is a solemn ?+--ev5 ! lea/ ?\ghtful is t\*$ by x--:5 a great intellect passes away into ! sil5ce & we see x no m4 ,su* a loss1 su* a void1 is pres5t1 ,i feel c]ta91 to _m "h to-day4 ,x is n (t51 ev5 9 ?is great home ( ?\ght & k1 t s bright a light is ext+ui%$ z t :i* is n[ m\rn$ by _m illu/ri\s m\rn]s1 "h *iefly1 b also f> beyond ?is place4 ,i %all be believ$ :5 ,i say 9 all simplicity t ,i wi% x _h fall5 to "s m compet5t tongue to put into words ^? feel+s ( rev]5t affection :i* are1 ,i am p]suad$1 upp]mo/ 9 _m he>ts on ?is ,sunday4 ,my poor words %all be few1 b believe me !y come f ! he>t4 ,y "k1 bre?r51 ) :at an eag] pride we foll[ ! =tunes ( ^? :om we h lov$ & rev]5c$ 9 our und]graduate days4 ,we may see !m b seldom1 few lett]s may pass betwe5 u1 b _! names are nev] common names4 ,!y nev] become to u only :at o!r m5 are4 ,:5 ,i came up to ,tr9ity tw5ty-eight ye>s ago1 ,james ,cl]k ,maxwell 0 j beg9n+ 8 second ye>4 ,8 position among u--,i speak 9 ! pres5ce ( _m :o rememb] t "t--0 unique4 ,he 0 ! "o ackn[l$g$ man ( g5ius among ! und]graduates4 ,we und]/ood ev5 !n t1 ?\gh b>ely ( age1 he 0 9 8 own l9e ( inquiry n a beg9n] b a ma/]4 ,8 "n 0 already a famili> "n to m5 ( sci5ce4 ,if he liv$1 x 0 c]ta9 t he 0 "o ( t small b sacr$ b& to :om x w\ld be giv5 to enl>ge ! b\nds ( human k4 ,x 0 a position :i* might h turn$ ! head ( a small] man2 b ! fri5d ( :om we 7 all s pr\d1 & :o seem$1 z x 71 to l9k u ?us e>ly ) ! great outside _w ( ! pione]s ( k1 _h "o ( ^? ri* & lavi% natures :i* no prosp]ity c impov]i%1 & :i* make fai? 9 goodness easy = o!rs4 ,i h (t5 ?\ght t ^? :o nev] knew ! gr& old ,adam ,s$gwick & ! !n "y & ev]-y\?ful ,cl]k ,maxwell _h yet to le>n ! l>g5ess & fulness ( ! m\lds 9 :i* "s *oice natures are fram$4 ,( ! sci5tific greatness ( our fri5d we 7 mo/ ( u unable to judge2 b anyone c\ld see & admire ! boy-l glee1 ! joy\s inv5tion1 ! wide read+1 ! eag] ?ir/ = tru?1 ! subtle ?\ght1 ! p]fect temp]1 ! unfail+ rev]5ce1 ! s+ul> abs5ce ( any ta9t ( ! brea? ( worldl9ess 9 any ( its ?\s& =ms4 8,bre?r51 y may "k su* m5 n[ among y\r college fri5ds1 ?\gh !re c be b few 9 any ye>1 or inde$ 9 any c5tury1 t possess ! r>e g5ius ( ! man :om we deplore4 ,if x be s1 !n1 if y w accept ! c\nsel ( a /rang]1 ?ank ,god = ,8 gift4 ,believe me :5 ,i tell y t few su* bless+s w come to y 9 lat] life4 ,!re are bless+s t come once 9 a lifetime4 ,"o ( ^! is ! rev]5ce ) :i* we look up to greatness & goodness 9 a college fri5d--above u1 beyond u1 f> out ( our m5tal or moral grasp1 b /ill "o ( u1 ne> to u1 our own4 ,y "k1 9 "p at lea/1 h[ 9 ?is case ! promise ( y\? 0 m ?an fulfill$1 & h[ ! man :o1 b a =tnight ago1 0 ! ornam5t ( ! ,univ]sity1 &--%all ,i be wrong 9 say+ x8--almo/ ! discov]] ( a new _w ( k1 0 ev5 m lov$ ?an he 0 admir$1 reta9+ aft] tw5ty ye>s ( fame t mir?1 t simplicity1 t *ild-l delight 9 all t is fre% & wond]ful :i* we rejoice to ?9k ( z "s ( ! sure/ accompanim5t ( true sci5tific g5ius4 8,y "k1 also1 t he 0 a dev\t z well z ?\ghtful ,*ri/ian4 ,i d n note ?is 9 ! triumphant _s ( a controv]siali/4 ,i w n = a mom5t assume t !re is any natural opposition betwe5 sci5tific g5ius & simple ,*ri/ian fai?4 ,i w n comp>e him ) o!rs :o h _h ! g5ius )\t ! fai?4 ,*ri/ianity1 ?\gh %e ?ankfully welcomes & deeply prizes !m1 does n ne$ n[1 any m ?an :5 ,/4 ,paul fir/ prea*$ ! ,cross at ,cor9?1 ! speculations ( ! subtle or ! wisdom ( ! wise4 ,if ,i wi%$ to %[ m51 especially "y m51 ! liv+ =ce ( ! ,gospel1 ,i w\ld take !m n s mu* to a le>n$ & dev\t ,*ri/ian man to :om all /ores ( k 7 famili>1 b to "s c\ntry village :]e = fifty ye>s !re _h be5 dev\t traditions & dev\t practice4 ,!re !y w\ld see ! ,gospel liv$ out2 tru?s1 :i* o!r m5 spoke (1 se5 & kn[n2 a _s n ( ?is _w1 visibly1 h\rly pres5t2 citiz5%ip 9 heav5 daily assum$ & daily realis$4 ,su* *>act]s ,i believe to be ! mo/ conv9c+ prea*]s to ^? :o ask :e!r ,revelation is a fable & ,god an unkn[able4 ,yes1 9 mo/ cases--n1 ,i admit1 9 all--simple fai?1 ev5 p]adv5ture m ?an dev\t g5ius1 is mighty = remov+ d\bts & implant+ fre% conviction4 ,b hav+ said ?is1 we may well give ?anks to ,god t our fri5d 0 :at he 01 a firm ,*ri/ian believ]1 & t 8 p[]ful m9d1 aft] rang+ at w ?r\gh ! illimitable spaces ( ,creation & almo/ h&l+ :at he call$ #8! f\ndation-/ones ( ! mat]ial univ]se1' f\nd its true re/ & happ9ess 9 ! love & ! m]cy ( ,him :om ! humble/ ,*ri/ian calls 8 ,fa!r4 ,( su* a man x may be truly said t he _h 8 citiz5%ip 9 heav51 & t he look$ =1 z a ,savi\r1 ! ,"l ,jesus ,*ri/1 ?r\gh :om ! unnumb]$ worlds 7 made1 & 9 ! lik5ess ( ^: image our new & spiritual body w be fa%ion$40 ,! ,tripos came 9 ,janu>y1 #ahed4 8,y w ne$ to get muffetees = ! ,s5ate ,room4 ,take y\r plaid or rug to wrap r\nd y\r feet & legs10 0 8 fa!r's advice--advice :i* w appeal to _m :o c rememb] ! ,s5ate ,h\se z x felt on a cold ,janu>y morn+4 ,maxwell _h be5 prep>+ c>efully = ?is exam9ation4 ,?us to 8 aunt1 ,miss ,cay1 9 ,june1 #ahec1 he writes3--8,if anyone asks h[ ,i am gett+ on 9 ma!matics1 say t ,i am busy arrang+ ev]y?+ s z to be able to express all di/9ctly1 s t exam9] may be satisfi$ n[ & pupils edifi$ h]eaft]4 ,x is pleasant "w & v /r5g!n+1 b n ne>ly f9i%$40 ,/ill1 ! illness ( ,july1 #ahec1 _h left "s effect4 ,pr(essor ,baynes /ates t he said t on ent]+ ! ,s5ate ,h\se = ! fir/ pap] he felt 8 m9d almo/ a blank1 b by-&-by 8 m5tal vision became pret]naturally cle>4 ,! mod]ators 7 ,mack5zie ( ,caius1 ^: advice _h be5 ma9ly in/rum5tal 9 lead+ him to migrate to ,tr9ity1 ,wm4 ,walton ( ,tr9ity1 ,wol/5holme ( ,*ri/'s1 & ,p]cival ,fro/ ( ,/4 ,john's4 ,:5 ! li/s 7 publi%$1 ,r\? ( ,pet]h\se 0 s5ior1 ,maxwell second4 ,! exam9ation = ! ,smi?'s ,prizes foll[$ 9 a few days1 & !n ,r\? & ,maxwell 7 decl>$ equal4 ,9 a lett] to ,miss ,cay#ag ( ,janu>y #ac?1 :ile wait+ = ! ?ree days' li/1 he writes3-- 8,all my correspond5ts h be5 writ+ to me1 :i* is k9d1 & h n be5 writ+ que/ions1 :i* is k9d]4 ,s ,i answ] y n[1 :ile ,i am slack+ spe$ to get up /eam1 leav+ ,lewis & ,/ew>t1 etc41 till next week1 :5 ,i w give an acc\nt ( ! five days4 ,!re are a good _m up "h at pres5t1 & we get on v jolly on ! :ole2 b "s are n well1 & "s are go+ to be pluck$ or gulph$1 z ! case may be1 & o!rs are read+ s h>d t !y are invisible4 ,i g to-morr[ to breakfa/ ) %aky m51 & aft] food ,i am to g & he> ! li/ read out1 & :e!r !y are ?r\gh1 & br+ !m ^w4 ,:5 ! hon\r li/ comes out ! poll m5 act z mess5g]s4 ,bob ,campbell comes 9 occasionally ( an ev5+ n[1 to discuss matt]s & v>y sports4 ,dur+ exam9ation ,i h _h m5 at night work+ ) gutta-p]*a1 magnets1 etc4 ,x is mu* bett] ?an read+ novels or talk+ aft] #e h\rs' h>d writ+40 ,8 fa!r1 on he>+ ! news1 wrote f ,ed9burgh3-- 8,i he>tily congratulate y on y\r place 9 ! li/4 ,i suppose x is high] ?an ! speculators w\ld h guess$1 & q z high z ,hopk9s reckon$ on4 ,i wi% y success 9 ! ,smi?'s ,prizes2 be sure to write me ! result4 ,i w see ,mrs4 ,morrieson1 & ,i ?9k ,i w call on ,dr4 ,gloag to congratulate him4 ,he has at lea/ ?ree pupils ga9+ hon\rs40 ,8 fri5ds 9 ,ed9burgh 7 greatly pleas$4 8,i get congratulations on all h&s10 8 fa!r writes1#ah 8includ+ ,pr(essor ,kell& & ,s&y ,fras] & all o!rs compet5t4444 ,to-night or on ,monday ,i %all expect to he> ( ! ,smi?'s ,prizes40 ,& aga91 ,febru>y #f?1 #ahed3--8;,george ,w$d]burn came into my room at #b a4m4 ye/]day morn+1 hav+ se5 ! ,saturday ,times1 receiv$ by ! express tra94444 ,z y are equal to ! ,s5ior 9 ! *ampion trial1 y are v little beh9d him40 ,or aga91 ,m>* #e?1 #ahed3-- 8,aunt ,jane /irr$ me up to sit = my picture1 z %e said y wi%$ = x & 7 entitl$ to ask = x qua ,wrangl]4 ,i h _h f\r sitt+s to ,sir ,john ,watson ,gordon1 & x is n[ f> advanc$2 ,i ?9k x is v l4 ,x is kitcat size1 to be a companion to ,dyce's picture ( y\r "m & self1 :i* ,aunt ,jane says %e is to leave to y40 ,& n[ ! long ye>s ( prep>ation 7 ne>ly ov]4 ,! cunn+ craftsman 0 fitt$ ) 8 tools2 he c\ld set to "w to unlock ! secrets ( ,nature2 he 0 free to employ 8 g5ius & 8 k on ^? tasks = :i* he felt mo/ fitt$4 ,,*apt] ,,iii4 ,,e>ly ,,rese>*es4--,,pr(essor ,,at ,,ab]de54 ,f ?is "t on ,maxwell's life becomes a record ( 8 writ+s & discov]ies4 ,x w1 h[ev]1 probably be cle>e/ to sep>ate z f> z possible biographical details f a detail$ acc\nt ( 8 sci5tific "w1 leav+ ?is = consecutive treatm5t 9 lat] *apt]s1 & only allud+ to x s f> z may prove necess>y to expla9 ref]5ces 9 8 lett]s4 ,he cont9u$ 9 ,cambridge till ! ,long ,vacation ( #ahed1 read+ ,mill's 8,logic40 8,i am exp]i5c+ ! effects ( ,mill10 he writes1 ,m>* #be?1 #ahed1 8b ,i take him sl[ly4 ,i d n ?9k him ! la/ ( 8 k9d4 ,i ?9k m is want$ to br+ ! connexion ( s5sation ) sci5ce to light1 & to %[ :at x is n40 ,he also read ,b]keley on 8,! ,!ory ( ,vision0 & 8greatly admir$ x40 ,ab\t ! same "t he devis$ an oph?almoscope4#ai 8,i h made an in/rum5t = see+ into ! eye ?r\gh ! pupil4 ,! difficulty is to ?r[ ! light 9 at t small hole & look 9 at ! same "t2 b t difficulty is ov]come1 & ,i c see a l>ge "p ( ! back ( ! eye q di/9ctly ) ! image ( ! c&le on x4 ,p f9d no inconv5i5ce 9 be+ exam9$1 & ,i h got dogs to sit q /ill & keep _! eyes /eady4 ,dogs' eyes are v beautiful beh9d--a copp]-col\r$ gr\nd1 ) glori\s bright pat*es & networks ( blue1 yell[1 & gre51 ) blood-vessels great & small40 ,aft] ! vacation he return$ to ,cambridge1 & ! lett]s ref] to ! col\r-top4 ,?us to ,miss ,cay1 ,novemb] #bd?1 #ahed1 p4 #bjh3-- 8,i h be5 v busy ( late ) v>i\s ?+s1 & am j beg9n+ to make pap]s = ! exam9ation at ,*elt5ham1 :i* ,i h to conduct ab\t ! #aa? ( ,decemb]4 ,i h also to make pap]s to poli% (f my pups4 )4 ,i h be5 sp9n+ col\rs a great deal1 & h got mo/ accurate results1 prov+ t ord9>y p's eyes are all made alike1 ?\gh "s are bett] ?an o!rs1 & t o!r p see two col\rs in/ead ( ?ree2 b all ^? :o d s agree among/ !mselves4 ,i h made a triangle ( col\rs by :i* y may make out ev]y?+4 8,if y c f9d out any p 9 ,ed9burgh :o d n see col\rs 7,i "k ! ,dicksons don't71 pray drop a h9t t ,i w\ld l to see !m4 ,i h put "o "h up to a dodge by :i* he di/+ui%es col\rs )\t fail4 ,i h also con/ruct$ a pair ( squ9t+ spectacles1 & am beg9n+ op]ations on a squ9t+ man40 ,a pap] writt5 = 8 own use orig9ally "s "t 9 #ahed1 b communicat$ z a p>t+ gift to 8 fri5d ,f>r>1 :o 0 ab\t to become a ma/] at ,m>lbor\gh1 gives u "s insight into 8 view ( life at ! age ( tw5ty-?ree4 8,he t w\ld enjoy life & act ) fre$om mu/ h ! "w ( ! day cont9ually be=e 8 eyes4 ,n ye/]day's "w1 le/ he fall into despair2 nor to-morr['s1 le/ he become a vision>y--n t :i* ends ) ! day1 :i* is a worldly "w2 nor yet t only :i* rema9s to et]nity1 = by x he _c %ape 8 actions4 8,happy is ! man :o c recognise 9 ! "w ( to-day a connect$ portion ( ! "w ( life & an embodim5t ( ! "w ( ,et]nity4 ,! f\ndations ( 8 confid5ce are un*angeable1 = he has be5 made a p>tak] ( ,inf9ity4 ,he /r5u\sly works out 8 daily ent]prises because ! pres5t is giv5 him = a possession4 8,?us ought ,man to be an imp]sonation ( ! div9e process ( nature1 & to %[ =? ! union ( ! inf9ite ) ! f9ite1 n slight+ 8 temporal exi/5ce1 rememb]+ t 9 x only is individual action possible2 nor yet %utt+ out f 8 view t :i* is et]nal1 kn[+ t ,"t is a my/]y :i* man _c endure to contemplate until et]nal ,tru? enlight5 x40 ,8 fa!r 0 unwell 9 ! ,*ri/mas vacation ( t ye>1 & he c\ld n return to ,cambridge at ! beg9n+ ( ! ,l5t t]m4 8,my /eps10 he writes#bj to ,c4 ,j4 ,munro f ,ed9burgh1 ,febru>y #ai?1 #ahee1 8w be no m by ! re$y & crook$ till ,ea/] t]m4444 ,i %\ld l to "k h[ _m kept bacalaurean weeks g to ea* ( ^! t]ms1 & :5 !y beg9 & end4 ,ov]haul ! ,cal5d>1 & :5 f\nd make note (40 ,he 0 back 9 ,cambridge = ! ,may t]m1 work+ at ! motion ( fluids & at 8 col\r-top4 ,a pap] on 8,exp]im5ts on ,col\r z ,p]ceiv$ by ! ,eye0 0 communicat$ to ! ,royal ,society ( ,ed9burgh on ,m>* #ai?1 #ahee4 ,! exp]im5ts 7 %[n to ! ,cambridge ,philosophical ,society 9 ,may foll[+1 & ! results are ?us describ$ 9 two lett]s#ba to 8 fa!r1 ,saturday1 ,may #e?1 #ahee3 8,! ,royal ,society h be5 v consid]ate 9 s5d+ me my pap] on #8,col\rs' j :5 ,i want$ x = ! ,philosophical "h4 ,i am to let !m see ! tricks on ,monday ev5+1 & ,i h be5 !re prep>+ _! exp]im5ts 9 ! gaslight4 ,!re is to be a meet+ 9 my rooms to-night to discuss ,adam ,smi?'s #8,!ory ( ,moral ,s5tim5ts1' s ,i mu/ cle> up my litt] pres5tly4 ,i am work+ away at electricity aga91 & h be5 work+ my way into ! views ( heavy ,g]man writ]s4 ,x takes a long "t to r$uce to ord] all ! notions "o gets f ^! m51 b ,i hope to see my way ?r\gh ! subject & arrive at some?+ intelligible 9 ! way ( a !ory4444 8,! col\r trick came (f on ,monday1 #g?4 ,i _h ! pro(-%eets ( my pap]1 & 0 go+ to read2 b ,i *ang$ my m9d & talk$ in/ead1 :i* 0 m to ! purpose4 ,!re 7 sundry m5 :o ?\ght t blue & yell[ make gre51 s ,i _h to undeceive !m4 ,i h got ,hay's book ( col\rs out ( ! ,univ4 ,libr>y1 & am work+ ?r\gh ! specim5s1 mat*+ !m ) ! top4 ,i h a new trick ( /ret*+ ! /r+ horizontally above ! top1 s z to t\* ! upp] "p ( ! axis4 ,! motion ( ! axis sets ! /r+ a-vibrat+ 9 ! same "t ) ! revolutions ( ! top1 & ! col\rs are se5 9 ! haze produc$ by ! vibration4 ,?omson has be5 sp9n+ ! top1 & he f9ds my diagram ( col\rs agrees ) 8 exp]im5ts1 b he d\bts ab\t br[ns1 :at is _! composition4 ,i h got colco?> br[n1 & c make :ite ) x1 & blue & gre52 also1 by mix+ r$ ) a little blue & gre5 & a great deal ( black1 ,i c mat* colco?> exactly4 8,i h be5 p]fect+ my in/rum5t = look+ into ! eye4 ,w>e has a little bea/ l old ,ask1 :i* sits q /eady & seems to l be+ look$ at1 & ,i h got sev]al m5 :o h l>ge pupils & d n wi% to let me look 94 ,i h se5 ! image ( ! c&le di/9ctly 9 all ! eyes ,i h tri$1 & ! ve9s ( ! ret9a 7 visible 9 "s2 b ! dogs' eyes %[$ all ! ramifications ( ve9s1 ) glori\s blue & gre5 network1 s t y might copy d[n ev]y?+4 ,i h %[n lots ( m5 ! image 9 my own eye by %utt+ (f ! light till ! pupil dilat$ & !n lett+ x on4 8,i am read+ ,electricity & work+ at ,fluid ,motion1 & h got out ! condition ( a fluid be+ able to fl[ ! same way = a l5g? ( "t & n wriggle ab\t40 ,! ,briti% ,association met at ,glasg[ 9 ,septemb]1 #ahee1 & ,maxwell 0 pres5t1 & %[$ 8 col\r-top at ,pr(essor ,ramsay's h\se to "s ( ^? int]e/$4 ,lett]s#bb to 8 fa!r ab\t ?is "t describe "s ( ! ev5ts ( ! meet+ & 8 own plans = ! t]m4 8,we _h a pap] f ,brew/] on #8,! !ory ( ?ree col\rs 9 ! spectrum1' 9 :i* he treat$ ,:ewell ) philosophic pity1 comm5d+ him to ! c>e ( ,pr(4 ,w>tman ( ,g5eva1 :o 0 consid]$ ! greate/ au?ority 9 cases ( 8 k9d--cases1 9 fact1 ( col\r-bl9dness4 ,:ewell 0 9 ! room1 b w5t out & avoid$ ! qu>rel2 & ,/okes made a few rem>ks1 /at+ ! case n only cle>ly b c\rte\sly4 ,h[ev]1 ,brew/] did n seem to see t ,/okes admitt$ 8 exp]im5ts to be correct1 & ! newspap]s repres5t$ ,/okes z call+ 9 "q ! accuracy ( ! exp]im5ts4 8,i am gett+ my electrical ma!matics into %ape1 & ,i see ?r\gh "s p>ts :i* 7 r hazy be=e2 b ,i d n f9d v mu* "t = x at pres5t1 because ,i am read+ ab\t heat & fluids1 s z n to tell lies 9 my lectures4 ,i got a note f ! ,society ( ,arts ab\t ! platomet]1 aw>d+ ?anks & (f]+ to defray ! exp5ses to ! ext5t ( #aj1 on ! ma*9e be+ produc$ 9 work+ ord]4 ,:5 ,i h arrang$ x 9 my head1 ,i int5d to write to ,james ,bryson ab\t x4 8,i got a long lett] f ,?omson ab\t col\rs & electricity4 ,he is beg9n+ to believe 9 my !ory ab\t all col\rs be+ capable ( ref]5ce to ?ree /&>d ones1 & he is v glad t ,i %\ld poa* on 8 electrical pres]ves4 8444 ,x is difficult to keep up "o's int]e/ 9 intellectual matt]s :5 fri5ds ( ! intellectual k9d are sc>ce4 ,h[ev]1 !re are pl5ty fri5ds n intellectual :o s]ve to br+ out ! active & practical habits ( m9d1 :i* ov]ly-intellectual p seldom d4 ,:]e=e1 if ,i am to be up ?is t]m1 ,i int5d to addict myself r to ! work+ m5 :o are gett+ up classes ?an to pups41 :o are 9 ! ma9 a vexation4 ,mean:ile1 !re is ! exam9ation to consid]4 8,y say ,dr4 ,wilson has s5t 8 book4 ,i w write & ?ank him4 ,i suppose x is ab\t col\r-bl9dness4 ,i int5d to beg9 ,poisson's pap]s on electricity & magnetism to-morr[4 ,i h got !m out ( ! libr>y4 ,my read+ hi!rto has be5 ( novels--#8,%irley' & #8,! ,newcomes1' & n[ #8,we/w>d ,ho4' 8,macmillan proposes to get up a book ( optics ) my assi/ance1 & ,i feel incl9$ = ! job4 ,!re is great bo!r 9 mak+ a ma!matical book1 especially on a subject ) :i* y are famili>1 = 9 correct+ x y d z y w\ld to pups4--look if ! pr9ciple & result is "r1 & =get to look out = small errors 9 ! c\rse ( ! "w4 ,h[ev]1 ,i expect ! "w w be salut>y1 z involv+ h>d "w1 & 9 ! end mu* abuse f coa*es & /ud5ts1 & c]ta9ly no va9 fame1 except 9 ,macmillan's puffs4 ,b1 if ,i h rightly conceiv$ ! plan ( an educational book on optics1 x w be v diff]5t 9 mann]1 ?\gh n 9 matt]1 f ^? n[ us$40 ,! exam9ation ref]r$ to 0 t = a ,fell[%ip at ,tr9ity1 & ,maxwell 0 elect$ on ,octob] #aj?1 #ahee4 ,he 0 imm$iately ask$ to lecture = ! ,college1 on hydro/atics & optics1 to ! upp] division ( ! ?ird ye>1 & to set pap]s = ! que/ioni/s4 ,9 consequ5ce1 he decl9$ to take pupils1 9 ord] to h "t = read+ & do+ private ma!matics1 & = see+ ! m5 :o att5d$ 8 lectures4 ,9 ,novemb] he writes3 8,i h be5 lectur+ two weeks n[1 & ! class seems improv+2 & !y come & ask que/ions1 :i* is a good sign4 ,i h be5 mak+ curves to %[ ! relations ( pressure & volume 9 gases1 & !y make ! subject easi]40 ,/ill1 he f\nd "t to att5d ,pr(essor ,willis's lectures on me*anism & to cont9ue 8 read+4 8,i h be5 read+10 he writes1 8old books on optics1 & f9d _m ?+s 9 !m f> bett] ?an :at is new4 ,! =eign ma!maticians are discov]+ = !mselves me?ods :i* 7 well kn[n at ,cambridge 9 #agbj1 b are n[ =gott540 ,! 8,poisson0 0 read to help him ) 8 own views on electricity1 :i* 7 rapidly matur+1 & ! fir/ ( t great s]ies ( works :i* has revolutionis$ ! sci5ce 0 publi%$ on ,decemb] #aj?1 #ahee1 :5 8 pap] on 8,f>aday's ,l9es ( ,=ce0 0 read to ! ,cambridge ,philosophical ,society4 ,! next t]m f\nd him back 9 ,cambridge at "w on 8 lectures1 full ( plans = a new col\r top & o!r matt]s4 ,e>ly 9 ,febru>y he receiv$ a lett] f ,pr(essor ,=bes1 tell+ him t ! ,pr(essor%ip ( ,natural ,philosophy 9 ,m>is*al ,college1 ,ab]de51 0 vacant1 & sugge/+ t he %\ld apply4 ,he decid$ to be a c&idate if 8 fa!r approv$4 8,= my own "p10 he writes1 8,i ?9k ! soon] ,i get into regul> "w ! bett]1 & t ! be/ way ( gett+ into su* "w is to pr(ess "o's read9ess by apply+ = x40 ,on ! #bj? ( ,febru>y he writes3 8,h[ev]1 wisdom is ( _m k9ds1 & ,i d n "k :i* dwells ) wise c\nsellors mo/1 :e!r sci5tific1 practical1 political1 or ecclesia/ical4 ,i he> !re are c&idates ( all k9ds rely+ on ! pr$om9ance ( "o or o!r ( ^! k9ds ( wisdom 9 ! con/itution ( ! ,gov]nm5t40 ,! second "p ( ! pap] on 8,f>aday's ,l9es ( ,=ce0 0 read dur+ ! t]m4 ,writ+ on ! #d? ( ,m>*1 he expresses ! hope soon to be able to write out fully ! pap]4 8,i h done no?+ 9 t way ?is t]m10 he says1 8b am j beg9n+ to feel ! electrical /ate come on aga940 ,8 fa!r 0 work+ at ,ed9burgh 9 support ( 8 c&idature = ,ab]de51 & :51 9 ! middle ( ,m>*1 he return$ ,nor?1 he f\nd ev]y?+ well prep>$4 ,! two return$ to ,gl5lair toge!r aft] a few days 9 ,ed9burgh1 & ,maxwell 0 prep>+ to g back to ,cambridge1 :51 on ! #bnd ( ,april1 8 fa!r di$ sudd5ly4 ,writ+ to ,mrs4 ,blackburn1 he says3 8,my fa!r di$ sudd5ly to-day at twelve o'clock4 ,he _h be5 giv+ directions ab\t ! g>d51 & he said he w\ld sit d[n & re/ a little1 z usual4 ,aft] a few m9utes ,i ask$ him to lie d[n on ! s(a1 & he did n seem incl9$ to d s2 & !n ,i got him "s e!r1 :i* _h help$ him be=e4 ,be=e he c\ld take any he _h a slight /ruggle1 & all 0 ov]4 ,he h>dly brea!d aft]w>ds40 ,almo/ imm$iately aft] ?is1 ,maxwell 0 appo9t$ to ,ab]de54 ,8 fa!r's dea? _h fru/rat$ "s at lea/ ( ! int5tions ) :i* he _h appli$ = ! po/4 ,he knew ! old man w\ld be glad to see him ! occupant ( a ,scot* *air4 ,he hop$1 too1 to be able to live ) 8 fa!r at ,gl5lair = "o half ! ye>2 b ?is 0 n to be4 ,no d\bt ! laboratory & ! fre$om ( ! po/1 :5 comp>$ ) ! r\t9e "w ( prep>+ m5 = ! ,tripos1 _h _! inducem5ts2 /ill1 x may be d\bt$ if ! *oice 0 a wise "o = him4 ,! "w ( drill+ classes1 compos$1 = ! mo/ "p1 ( raw untra9$ lads1 9 ! elem5ts ( physics & me*anics 01 z ,niv5 says 9 8 preface to ! collect$ works1 n t = :i* he 0 be/ fitt$2 :ile at ,cambridge1 _h he /ay$1 he mu/ always h _h among 8 pupils "s ( ! be/ ma!maticians ( ! "t2 & he might h f\nd$ "s t5 or fifte5 ye>s be=e he did t ,cambridge ,s*ool ( ,physici/s :i* looks back ) s mu* pride to him z _! ma/]4 ,leave-tak+ at ,tr9ity 0 a sad task4 ,he writes#bc ?us1 ,june #d?1 to ,mr4 ,r4 ,b4 ,lit*field3-- 8,on ,?ursday ev5+ ,i take ! ,nor?-,we/]n r\te to ! ,nor?4 ,i am busy look+ ov] imm5se rubbi% ( pap]s1 etc41 = "s ?+s n to be burnt lie among mu* combu/ible matt]1 & "s is s(t & good = pack+4 8,x is n pleasant to g d[n to live solit>y1 b x w\ld n be pleasant to /ay up ei!r1 :5 all "o _h to d lay else:]e4 ,! transition /ate f a man into a ,don mu/ come at la/1 & x mu/ be pa9ful1 l gradual outroot+ ( n]ves4 ,:5 x is done !re is no m pa91 b occasional rem9d]s f "s suck]s1 tap-roots1 or o!r remnants ( ! old n]ves1 j to %[ :at 0 !re & :at might h be540 ,! summ] ( #ahef 0 sp5t at ,gl5lair1 :]e v>i\s fri5ds 7 8 gue/s--,lu%+ton1 ,mac,lennan1 ! two c\s9s ,cay1 & o!rs4 ,he cont9u$ to "w at optics1 electricity1 & magnetism1 & 9 ,octob] 0 busy ) 8a solemn address or manife/o to ! ,natural ,philosoph]s ( ! ,nor?1 :i* ne$$ c(fee & an*ovies & a ro>+ hot fire & spread coat-tails to make x natural40 ,?is 0 8 inaugural lecture4 ,9 ,novemb] he 0 at ,ab]de54 ,lett]s#bd to ,miss ,cay1 ,pr(essor ,campbell1 & ,c4 ,j4 ,munro tell ( ! "w ( ! session4 ,! la/ is f ,gl5lair1 dat$ ,may #bj?1 #aheg1 aft] "w 0 ov]4 8,! session w5t (f smoo?ly en\gh4 ,i _h ,sun1 all ! beg9n+ ( optics1 & work$ (f all ! exp]im5tal "p up to ,fraunh(]'s l9es1 :i* 7 glori\s to see ) a wat]-prism ,i h set up 9 ! =m ( a cubical box1 five in* side4444 8,i succe$$ v well ) heat4 ,! exp]im5ts on lat5t heat came out v accurate4 ,t 0 my "p1 & ! class c\ld expla9 & "w out ! results bett] ?an ,i expect$4 ,next ye> ,i int5d to mix exp]im5tal physics ) me*anics1 devot+ ,tuesday & ,,?ursday 7:at w\ld ,/okes say87 to ! sci5ce ( exp]im5t+ accurately4444 8,la/ week ,i brew$ *lorophyll 7z ! *emi/s ^w x71 a gre5 liquor1 :i* turns ! invisible light r$4444 8,my la/ gr9d 0 ! r$uction ( equations ( col\r :i* ,i made la/ ye>4 ,! result 0 em95tly satisfactory40 ,ano!r lett]1#be ,june #e?1 #aheg1 also to ,munro1 ref]s to ! "w ( ! ,univ]sity ,commission & ! new /atutes4 8,i h n se5 ,article #g1 b ,i agree ) y\r diss5t f x entirely4 ,on ! ve/$ int]e/ pr9ciple1 ,i ?9k ! m5 :o int5d$ to keep _! fell[%ips by celibacy & ord9ation1 & got !m on t foot+1 %\ld n be all[$ to des]t ! virg9 *oir or neglect ! prie/ly (fice1 b on ^? pr9ciples %\ld be all[$ to live out _! days1 provid$ ! :ole am\nt ( s\ls cur$ annually does n am\nt to #bj 9 ! ,k+'s ,book4 ,b my doctr9e is t ! v>i\s grades ( ,college (fic]s %\ld be set on su* a basis t1 al?\gh *ance lectur]s might be sometimes *os5 f among fre% fell[s :o are go+ away soon1 ! reliable assi/ant tutors1 & ^? t h a pla9 call+ t way1 %\ld1 aft] a few ye>s1 be elect$ p]man5t (fic]s ( ! ,college1 & be tutors & deans 9 _! "t1 & s5iors also1 ) leave to m>ry1 or1 r1 nev] prohibit$ or ask$ any que/ions on t head1 & ) leave to retire aft] s _m ye>s' s]vice z s5iors4 ,z = ! m5 ( ! _w1 we %\ld h a limit$ t]m ( exi/5ce1 & t indep5d5t ( m>riage or #8p>sonage4'0 ,x 0 m ?an tw5ty ye>s be=e ! s*eme outl9$ 9 ! above lett] came to any?+2 b1 at ! "t ( ,maxwell's dea? 9 #ahgi1 ano!r ,commission 0 sitt+1 & ! plan sugge/$ by ,maxwell became ! basis ( ! /atutes ( ne>ly all ! colleges4 ,= ! w9t] session ( #aheg-eh he 0 aga9 at ,ab]de54 ,! ,adams ,prize _h be5 e/abli%$ 9 #ahdh by "s memb]s ( ,/4 ,john's ,college1 & connect$ by !m ) ! "n ( ,adams 89 te/imony ( _! s5se ( ! hon\r he _h conf]r$ ^u 8 ,college & ! ,univ]sity by hav+ be5 ! fir/ among ! ma!maticians ( ,europe to det]m9e f p]turbations ! unkn[n place ( a di/urb+ planet ext]ior to ,uranus40 ,pr(essor ,*allis1 ,dr4 ,p>k9son1 & ,sir ,william ,?omson1 ! exam9]s1 _h select$ z ! subject = ! prize to be aw>d$ 9 #aheg ! 8,motions ( ,saturn's ,r+s40 ,= ?is ,maxwell _h decid$ to compete1 & 8 lett]s at ! end ( #aheg tell ( ! progress ( ! task4 ,?us1 writ+#bf to ,lewis ,campbell f ,gl5lair on ,augu/ #bh?1 he says3-- 8,i h be5 batt]+ away at ,saturn1 return+ to ! *>ge e n[ & !n4 ,i h effect$ sev]al brea*es 9 ! solid r+1 & n[ ,i am spla% into ! fluid "o1 amid a cla% ( symbols truly a/\nd+4 ,:5 ,i reappe> x w be 9 ! dusky r+1 :i* is some?+ l ! /ate ( ! air suppos+ ! siege ( ,seba/opol conduct$ f a =e/ ( guns #ajj miles "o way1 & #cj1jjj miles ! o!r1 & ! %ot nev] to /op1 b g sp9n+ away r\nd a circle1 radius #agj1jjj miles40 ,& aga9#bg to ,miss ,cay on ! #bh? ( ,novemb]3-- 8,i h be5 pretty /eady at "w s9ce ,i came4 ,! class is small & n bright1 b ,i am go+ to give !m pl5ty to d f ! fir/1 & ,i f9d x a good plan4 ,i h a l>ge att5dance ( my old pupils1 :o g on ) ! high] subjects4 ,?is is n "p ( ! ,college c\rse1 s !y come m]ely f *oice1 & ,i h begun ) ! lea/ amus+ "p ( :at ,i int5d to give !m4 ,_m _h be5 read+ 9 summ]1 = !y did v good pap]s = me on ! old subjects at ! beg9n+ ( ! mon?4 ,mo/ ( my sp>e "t ,i h be5 do+ ,saturn's r+s1 :i* is gett+ on n[1 b lately ,i h _h a great _m long lett]s to write--"s to ,gl5lair1 "s to private fri5ds1 & "s all ab\t sci5ce4444 ,i h _h lett]s f ,?omson & ,*allis ab\t ,saturn--f ,hayw>d1 ( ,durham ,univ]sity1 ab\t ! brass top1 ( :i* he wants "o4 ,he says t ! e>? has be5 really f\nd to *ange its axis regul>ly 9 ! way ,i suppos$4 ,f>aday has also be5 writ+ ab\t 8 own subjects4 ,i h _h also to write ,=bes a long report on col\rs2 s t = e note ,i h got ,i h _h to write a c\ple ( %eets 9 reply1 & report+ progress takes a deal ( writ+ & spell+40 ,he devis$ a model 7n[ at ! ,cav5di% ,laboratory7 to exhibit ! motions ( ! satellites 9 a di/urb$ r+1 8= ! edification ( s5sible image-wor%ipp]s40 ,! essay 0 aw>d$ ! prize1 & secur$ = its au?or great cr$it among sci5tific m54 ,9 ano!r lett]1 writt5 dur+ ! same session1 he says3 8,i f9d my pr9cipal "w "h is tea*+ my m5 to avoid vague expressions1 z #8a c]ta9 =ce1' mean+ unc]ta92 may in/ead ( mu/2 w be in/ead ( is2 proportional in/ead ( equal40 ,! dea?1 dur+ ! autumn1 ( 8 ,college fri5d ,pom]oy1 f fev] 9 ,india1 0 a great bl[ to him2 8 lett]s at ! "t %[ ! dep? ( 8 feel+s & 8 beliefs4 ,! "q ( ! fusion ( ! two ,colleges at ,ab]de51 ,k+'s ,college & ! ,m>is*al ,college1 0 com+ to ! =e4 8,"k all m510 he says1 9 a lett] to ,pr(essor ,campbell1 8t ,i am a ,fusioni/40 ,9 ,febru>y1 #aheh1 he 0 /ill engag$ on ,saturn's r+s1 :ile h>d at "w dur+ ! same "t ) 8 classes4 ,he _h e/abli%$ a volunt>y class = 8 /ud5ts ( ! previ\s ye>1 & 0 read+ ) !m ,newton's 8,lun> ,!ory & ,a/ronomy40 ,?is 0 foll[$ by 8,electricity & ,magnetism10 ,f>aday's book be+ ! backbone ( ev]y?+1 8z he himself is ! nucleus ( ev]y?+ electric s9ce #ahcj40 ,9 ,febru>y1 #aheh1 he ann\nc$ 8 engagem5t to ,ka!r9e ,m>y ,dew>1 ! daught] ( ! ,pr9cipal ( ,m>is*al ,college4 8,de> ,aunt0 7he says1#bh ,febru>y #ah?1 #aheh71 8?is comes to tell y t ,i am go+ to h a wife4444 8,don't be afraid2 %e is n ma!matical1 b !re are o!r ?+s besides t1 & %e c]ta9ly won't /op ma!matics4 ,! only "o t c speak z an eye-witness is ,johnnie1 & he only saw h] :5 we 7 bo? try+ to act ! indiff]5t4 ,we h be5 try+ x s9ce1 b x w\ld n d1 & x 0 n good = ei!r40 ,! w$d+ took place e>ly 9 ,june4 ,pr(essor ,campbell has pres]v$ "s ( ! lett]s writt5 by ,maxwell to ,miss ,dew>1 & ^! conta9 8! record ( feel+s :i* 9 ! ye>s t foll[$ 7 transfus$ 9 action & embodi$ 9 a m>ri$ life :i* c only be spok5 ( z "o ( unexampl$ devotion40 ,! project = ! fusion ( ! two ,colleges1 to :i* ref]5ce has be5 made1 w5t on1 & ! s*eme 0 complet$ 9 #ahfj4 ,! two ,colleges 7 unit$ to =m ! ,univ]sity ( ,ab]de51 & ! new *air ( ,natural ,philosophy ?us creat$ 0 fill$ by ! appo9tm5t ( ,david ,?omson1 ,pr(essor ( ,natural ,philosophy 9 ,k+'s ,college1 & ,maxwell's s5ior4 ,mr4 ,w4 ,d4 ,niv51 9 8 preface to ,maxwell's works1 :5 deal+ ) ?is appo9tm5t1 writes3-- 8,pr(essor ,?omson1 ?\gh n comp>able to ,maxwell z a physici/1 0 nev]!less a rem>kable man4 ,he 0 di/+ui%$ by s+ul> =ce ( "* & great adm9i/rative faculty1 & he _h be5 prom95t 9 br++ ab\t ! fusion ( ! ,colleges4 ,he 0 also an admirable lectur] & tea*]1 & _h done mu* to raise ! /&>d ( sci5tific education 9 ! nor? ( ,scotl&4 ,?us ! *oice made by ! ,commission]s1 ?\gh almo/ inevitable1 _h ! effect ( mak+ x appe> t ,maxwell fail$ z a tea*]4 ,!re seems1 h[ev]1 to be no evid5ce to support su* an inf]5ce4 ,on ! contr>y1 if we may judge f ! numb] ( volunt>y /ud5ts att5d+ 8 classes 9 8 la/ ,college session1 he w\ld seem to h be5 z popul> z a pr(essor z he 0 p]sonally e/imable40 ,! "q :e!r ,maxwell 0 a great tea*] has sometimes be5 discuss$4 ,i tru/ t ! foll[+ pages w give an answ] to x4 ,he 0 n a prom95t lectur]4 ,z ,pr(essor ,campbell says1#bi 8,betwe5 8 /ud5ts' ignorance & 8 va/ k x 0 difficult to f9d a common measure4 ,! advice :i* he once gave to a fri5d ^: duty x 0 to prea* to a c\ntry congregation1 #8,:y don't y give x !m ?9n]8' mu/ (t5 h be5 applicable to himself4444 ,illu/rations ( ignotum p] ignotius1 or ( ! ab/ruse by "s unobs]v$ prop]ty ( ! famili>1 7 multipli$ ) dazzl+ rapidity4 ,!n ! _s ( indirectness & p>adox1 ?\gh he 0 aw>e ( its dang]s1 w\ld (t5 take possession ( him aga9/ 8 w1 &1 ei!r f %yness or mom5t>y excitem5t1 or ! despair ( mak+ himself und]/ood1 w\ld l& him 9 #8*aotic /atem5ts1' break+ (f ) "s quirk ( ironical hum\r40 ,b tea*+ is n all done by lectur+4 ,8 books & pap]s are va/ /oreh\ses ( sugge/ions & ideas :i* ! able/ m9ds ( ! pa/ tw5ty ye>s h be5 s9ce develop+4 ,to talk ) him = an h\r 0 to ga9 inspiration = a ye>'s "w2 to see 8 en?usiasm & to w9 8 praise or comm5dation 7 en\gh to comp5sate = _m we>y /ruggles ov] "s /ubborn piece ( app>atus :i* w\ld n g "r1 or "s small s\rce ( error :i* ?reat5$ to prove intractable & decl9$ to submit itself to calculation4 ,! sure judgm5t ( po/]ity w confirm ! v]dict t ,cl]k ,maxwell 0 a great tea*]1 ?\gh lectur+ to a cr[d ( untra9$ und]graduates 0 a task = :i* o!rs 7 bett] fitt$ ?an he4 ,,*apt] ,,iv4 ,,pr(essor ,,at ,,k+',s ,,college1 ,,london4--,,life ,,at ,,gl5lair4 ,9 #ahfj ,=bes resign$ ! *air ( ,natural ,philosophy at ,ed9burgh4 ,maxwell & ,tait 7 c&idates1 & ,tait 0 appo9t$4 ,9 ! summ] ( ! same ye> ,maxwell obta9$ ! vacant ,pr(essor%ip ( ,natural ,philosophy at ,k+'s ,college1 ,london4 ,?is he held to #ahfe1 & ?is p]iod ( 8 life is di/+ui%$ by ! appe>ance ( "s ( 8 mo/ important pap]s4 ,! "w 0 ardu\s2 ! ,college c\rse ext5d$ ov] n9e mon?s ( ! ye>2 !re 7 z well ev5+ lectures to artisans z "p ( 8 regul> duties4 ,8 life 9 ,london 0 useful to him 9 ! opportunities x gave him = becom+ p]sonally acqua9t$ ) ,f>aday & o!rs4 ,he also r5ew$ 8 intimacy ) v>i\s ,cambridge fri5ds4 ,he 0 at ! celebrat$ ,ox=d meet+ ( ! ,briti% ,association 9 #ahfj1 :]e he exhibit$ 8 col\r-box = mix+ ! col\rs ( ! spectrum4 ,9 #ahei1 at ! meet+ at ,ab]de51 he _h read to ,section ,a 8 fir/ pap] on ! 8,dynamical ,!ory ( ,gases10 publi%$ 9 ! ,philosophical ,magaz9e = ,janu>y1 #ahfj4 ,! second "p ( ! pap]1 deal+ ) ! conduction ( heat & o!r ph5om5a 9 a gas1 0 publi%$ 9 ,july1 #ahfj1 aft] ! ,ox=d meet+4 ,a pap] on ! 8,!ory ( ,comp\nd ,col\rs0 0 communicat$ to ! ,royal ,society by ,pr(essor ,/okes 9 ,janu>y1 #ahfj4 ,x conta9s ! acc\nt ( 8 col\r-box 9 ! =m f9ally adopt$ 7mo/ ( ! important p>ts ( ! app>atus are /ill at ! ,cav5di% ,laboratory71 & a numb] ( obs]vations by ,mrs4 ,maxwell & himself1 :i* w be m fully describ$ lat]4 ,9 ,novemb]1 #ahfj1 he receiv$ = ?is "w ! ,rum=d m$al ( ! ,royal ,society4 ,! next ye>1 #ahfa1 is ( great importance 9 ! hi/ory ( electrical sci5ce4 ,! ,briti% ,association met at ,man*e/]1 & a ,committee 0 appo9t$ on ,/&>ds ( ,electrical ,resi/ance4 ,maxwell 0 n a memb]4 ,! committee report$ at ! ,cambridge meet+ 9 #ahfb1 & 7 reappo9t$ ) ext5d$ duties4 ,maxwell's "n1 among o!rs1 0 add$1 & he took a prom95t "p 9 ! delib]ations ( ! committee1 :i*1 z _! ,report#cj pres5t$ 9 #ahfc /ates1 came to ! op9ion1 8aft] mature consid]ation1 t ! sy/em ( s-call$ absolute electrical units1 bas$ on purely me*anical measurem5ts1 is n only ! be/ sy/em yet propos$1 b is ! only "o consi/5t ) our pres5t k bo? ( ! relations exi/+ betwe5 ! v>i\s electrical ph5om5a & ( ! connection betwe5 ^! & ! fundam5tal measurem5ts ( "t1 space1 & mass40 ,app5dix ,c ( ?is ,report1 8,on ! ,elem5t>y ,relations betwe5 ,electrical ,measurem5ts10 be>s ! names ( ,cl]k ,maxwell & ,fleem+ ,j5k91 & is ! f\ndation ( ev]y?+ t has be5 done 9 ! way ( absolute electrical measurem5t s9ce t date2 :ile ,app5dix ,d gives an acc\nt by ! same two work]s ( ! exp]im5ts on ! absolute unit ( electrical resi/ance made 9 ! laboratory ( ,k+'s ,college by ,maxwell1 ,fleem+ ,j5k91 & ,balf\r ,/ew>t4 ,fur!r exp]im5ts are describ$ 9 ! report = #ahfd4 ,! "w ?us begun 0 consummat$ dur+ ! ye> #ahid by ! legalisation ?r\gh\t ! civilis$ _w ( a sy/em ( electrical units bas$ on ^? describ$ 9 ^! reports4 ,mean:ile1 ,maxwell's views on electro-magnetic !ory 7 quietly develop+4 ,pap]s on 8,physical ,l9es ( ,=ce10 :i* appe>$ 9 ! ,philosophical ,magaz9e dur+ #ahfa & #ahfb1 conta9 ! g]ms ( 8 !ory--express$ at t "t1 x is true1 9 a some:at mat]ial =m4 ,9 ! pap] publi%$ ,janu>y1 #ahfb1 ! n[ well-kn[n relation betwe5 ! ratio ( ! electric units & ! velocity ( light 0 e/abli%$1 & 8 correspond5ce ) ,fleem+ ,j5k9 & ,c4 ,j4 ,munro ab\t ?is "t relates 9 "p to ! exp]im5tal v]ification ( ?is relation4 ,8 exp]im5ts on ?is matt] 7 publi%$ 9 ! 8,philosophical ,transactions0 = #ahfh4 ,?is electrical !ory occupi$ 8 m9d ma9ly dur+ #ahfc & #ahfd4 ,9 ,septemb] ( ! latt] ye> he writes#ca f ,gl5lair to ,c4 ,hock91 :o _h tak5 ,balf\r ,/ew>t's place dur+ ! second s]ies ( exp]im5ts on ! measurem5t ( resi/ance4 8,i h be5 do+ sev]al electrical problems4 ,i h got a !ory ( #8electric absorption1' i4e41 residual *>ge1 etc41 & ,i v mu* want det]m9ations ( ! specific induction1 electric resi/ance1 & absorption ( good dielectrics1 su* z glass1 %ell-lac1 gutta-p]*a1 ebonite1 sulphur1 etc4 8,i h also cle>$ ! electromagnetic !ory ( light f all unw>rantable assumption1 s t we may safely det]m9e ! velocity ( light by measur+ ! attraction betwe5 bodies kept at a giv5 diff]5ce ( pot5tial1 ! value ( :i* is kn[n 9 electromagnetic measure4 8,i hope !re w be resi/ance coils at ! ,briti% ,association40 ,?is "w result$ 9 8 greate/ electrical pap]1 8,a ,dynamical ,!ory ( ! ,electromagnetic ,field10 read to ! ,royal ,society ,decemb] #h?1 #ahfd4 ,b ! molecul> !ory ( gases 0 /ill prom95tly be=e 8 m9d4 ,9 #ahfb1 writ+#cb to ,h4 ,r4 ,droop1 he says3-- 8,"s "t ago1 :5 inve/igat+ ,b]n\lli's !ory ( gases1 ,i 0 surpris$ to f9d t ! int]nal friction ( a gas 7if x dep5ds on ! collision ( p>ticles7 %\ld be indep5d5t ( ! d5sity4 8,/okes has be5 exam9+ ,graham's exp]im5ts on ! rate ( fl[ ( gases ?r\gh f9e tubes1 & he f9ds t ! friction1 if indep5d5t ( d5sity1 acc\nts = ,graham's results2 b1 if tak5 proportional to d5sity1 diff]s f ^? results v mu*4 ,?is seems r a curi\s result1 & an additional ph5om5on1 expla9$ by ! #8collision ( p>ticles' !ory ( gases4 ,/ill "o ph5om5on goes aga9/ t !ory--! relation betwe5 specific heat at con/ant pressure & at con/ant volume1 :i* is 9 air #adjh1 :ile x ought to be #accc40 ,& aga9#cc 9 ! same ye>1 #ba/ ,april1 #ahfb1 to ,lewis ,campbell3-- 8,h]r ,clausius ( ,zri*1 "o ( ! heat philosoph]s1 has be5 work+ at ! !ory ( gases be+ little bodies fly+ ab\t1 & has f\nd "s cases 9 :i* he & ,i don't tally4 ,s ,i am work+ x out aga94 ,sev]al exp]im5tal results h turn$ up lately r confirmatory ?an o!rwise ( t !ory4 8,i hope y enjoy ! abs5ce ( pupils4 ,i f9d ! division ( !m into small] classes is a great help to me & to !m2 b ! total oblivion ( !m = def9ite int]vals is a necess>y condition = do+ !m ju/ice at ! prop] "t40 ,! exp]im5ts on ! viscosity ( gases1 :i* =m$ ! ,bak]ian ,lecture to ! ,royal ,society read on ,febru>y #h?1 #ahff1 7 ! outcome ( ?is "w4 ,8 h\se 9 #h1 ,palace ,g>d5s1 ,k5s+ton1 conta9$ a l>ge g>ret runn+ ! complete l5g?4 8,to ma9ta9 ! prop] temp]ature a l>ge fire 0 = "s days kept up 9 ! room 9 ! mid/ ( v hot wea!r4 ,kettles 7 kept on ! fire & l>ge quantities ( /eam all[$ to fl[ into ! room4 ,mrs4 ,maxwell act$ z /ok]1 :i* 0 v exhau/+ "w :5 ma9ta9$ = sev]al consecutive h\rs4 ,aft] ?is ! room 0 kept cool = subsequ5t exp]im5ts by ! employm5t ( a consid]able am\nt ( ice40 ,next ye>1 ,may1 #ahff1 0 read 8 pap] on ! 8,dynamical ,!ory ( ,gases10 9 :i* errors 9 8 =m] pap]s1 :i* _h be5 po9t$ out by ,clausius1 7 correct$4 ,mean:ile he _h resign$ 8 ,london ,pr(essor%ip at ! end ( ! ,session ( #ahfe1 & _h be5 succe$$ by ,pr(essor ,w4 ,g4 ,adams4 ,= ! next f\r ye>s he liv$ *iefly at ,gl5lair1 work+ at 8 !ory ( electricity1 occasionally1 z we %all see1 visit+ ,london & ,cambridge1 & tak+ an active int]e/ 9 ! affairs ( 8 own neighb\rhood4 ,9 #ahfe he _h a s]i\s illness1 ?r\gh :i* he 0 nurs$ ) great c>e by ,mrs4 ,maxwell4 ,8 correspond5ce 0 consid]able1 & absorb$ mu* ( 8 "t4 ,mu* also 0 giv5 to ! /udy ( ,engli% lit]ature2 he 0 fond ( read+ ,*auc]1 ,milton1 or ,%akespe>e al\d to ,mrs4 ,maxwell4 ,he also read mu* !ological & philosophical lit]ature1 & all he read help$ only to /r5g!n t firm fai? 9 ! fundam5tals ( ,*ri/ianity 9 :i* he liv$ & di$4 ,9 #ahfg he & ,mrs4 ,maxwell paid a visit to ,italy1 :i* 0 a s\rce ( great pleasure to bo?4 ,8 *ief sci5tific "w 0 ! prep>ation ( 8 8,electricity & ,magnetism10 :i* did n appe> till #ahgc2 ! "t 0 9 ! ma9 "o ( quiet ?\ght & prep>ation = 8 next great task1 ! f\ndation ( ! ,s*ool ( ,physics 9 ,cambridge4 ,9 #ahfh ! pr9cipal%ip ( ! ,unit$ ,college 9 ! ,univ]sity ( ,/4 ,&rews 0 vacant by ! resignation ( ,=bes1 & ,maxwell 0 invit$ by sev]al ( ! pr(essors to /&4 ,he1 h[ev]1 decl9$ to submit 8 "n to ! ,cr[n4 ,,*apt] ,v4 ,,cambridge4--,,pr(essor ,,( ,,physics4 ,dur+ 8 retirem5t at ,gl5lair f #ahfe to #ahgj ,maxwell 0 frequ5tly at ,cambridge4 ,he exam9$ 9 ! ,ma!matical ,tripos 9 #ahff & #ahfg1 & aga9 9 #ahfi & #ahgj4 ,! regulations = ! ,tripos _h be5 9 =ce practically un*ang$ s9ce #ahdh1 & x 0 felt by _m t ! range ( subjects includ$ 0 n suffici5tly ext5sive1 & t *anges 7 urg5tly ne$$ if ,cambridge 7 to reta9 its position z ! c5tre ( ma!matical tea*+4 ,natural ,philosophy 0 m5tion$ 9 ! ,s*$ule1 b ,natural ,philosophy includ$ only ,dynamics & ,a/ronomy1 ,hydro/atics & ,physical ,optics1 ) "s simple ,hydrodynamics & ,s\nd4 ,! subjects ( ,heat1 ,electricity & ,magnetism1 ! ,!ory ( ,ela/ic ,solids & ,vibrations1 ,vortex-,motion 9 ,hydrodynamics1 & mu* else1 7 practically new s9ce #ahdh4 ,/okes1 ,?omson1 & ,maxwell 9 ,engl&1 & ,helmholtz 9 ,g]many1 _h creat$ !m4 ,accord+ly 9 ,june1 #ahfh1 a new plan ( exam9ations 0 sanction$ by ! ,s5ate to come into =ce 9 ,janu>y1 #ahgc1 & ^! v>i\s subjects 7 explicitly includ$4 ,mr4 ,niv51 :o 0 "o ( ^? exam9$ by ,maxwell 9 #ahff1 writes 9 ! preface to ! collect$ works3-- 8,= "s ye>s previ\s to #ahff1 :5 ,maxwell return$ to ,cambridge z ,mod]ator 9 ! ,ma!matical ,tripos1 ! /udies 9 ! ,univ]sity _h lo/ t\* ) ! great sci5tific movem5ts go+ on outside h] walls4 ,x 0 said t "s ( ! subjects mo/ 9 vogue _h b little int]e/ = ! pres5t g5]ation1 & l\d compla9ts began to be he>d t :ile su* bran*es ( k z ,heat1 ,electricity1 & ,magnetism 7 left out ( ! ,tripos exam9ation1 ! c&idates 7 wa/+ _! "t & en]gy ^u ma!matical trifles b>r5 ( sci5tific int]e/ & ( practical results4 ,into ! movem5t = re=m ,maxwell ent]$ w>mly4 ,by 8 que/ions 9 #ahff1 & subsequ5t ye>s1 he infus$ new life into ! exam9ation2 he took an active "p 9 draft+ ! new s*eme introduc$ 9 #ahgc2 b mo/ ( all by 8 writ+s he ex]t$ a p[]ful influ5ce on ! y\ng] memb]s ( ! ,univ]sity1 & 0 l>gely in/rum5tal 9 br++ ab\t ! *ange :i* has be5 n[ effect$40 ,b ! ,univ]sity possess$ no means ( tea*+ ^! subjects1 & a ,syndicate or ,committee 0 appo9t$1 ,novemb] #be?1 #ahfh1 8to consid] ! be/ means ( giv+ in/ruction to /ud5ts 9 ,physics1 especially 9 ,heat1 ,electricity & ,magnetism1 & ! me?ods ( provid+ app>atus = ?is purpose40 ,dr4 ,cookson1 ,ma/] ( ,/4 ,pet]'s ,college1 took an active "p 9 ! "w ( ! ,syndicate4 ,pr(essor ,/okes1 ,pr(essor ,live+1 ,pr(essor ,humphry1 ,dr4 ,phe>1 & ,dr4 ,r\? 7 among ! memb]s4 ,maxwell himself 0 9 ,cambridge t w9t]1 z ,exam9] = ! ,tripos1 & 8 "w z ,mod]ator & ,exam9] 9 ! two previ\s ye>s _h done mu* to %[ ! necessity ( alt]ations & to indicate ! direction :i* *anges %\ld take4 ,! ,syndicate report$ ,febru>y #bg?1 #ahfi4 ,!y call$ att5tion to ! ,report ( ! ,royal ,commission ( #ahej4 ,! ,commission]s _h 8prom95tly urg$ ! importance ( cultivat+ a k ( ! great bran*es ( ,exp]im5tal ,physics 9 ! ,univ]sity02 & 9 page #aah ( _! ,report1 aft] comm5d+ ! mann] 9 :i* ! subject ( ,physical ,optics is /udi$ 9 ! ,univ]sity1 & po9t+ out t 8!re is1 p]haps1 no public in/itution :]e x is bett] repres5t$ or prosecut$ ) m zeal & success 9 ! way ( orig9al rese>*10 !y _h /at$ t 8no reason c be assign$ :y o!r great bran*es ( ,natural ,sci5ce %\ld n become equally objects ( att5tion1 or :y ,cambridge %\ld n become a great s*ool ( physical & exp]im5tal1 z x is already ( ma!matical & classical1 in/ruction40 ,& aga9 ! ,commission]s rem>k3 8,9 a ,univ]sity s ?or\ghly imbu$ ) ! ma!matical _s1 physical /udy might be expect$ to assume )9 its prec9cts its highe/ & sev]e/ tone1 be /udi$ "u m ab/ract =ms1 ) m cont9ual ref]5ce to ma!matical laws1 & !re=e ) bett] hope ( br++ !m "o by "o "u ! doma9 ( ma!matical inve/igation ?an else:]e40 ,aft] call+ att5tion to ^! /atem5ts ! ,report ( ! ,syndicate !n cont9ues3-- 8,9 ! s*eme ( ,exam9ation = ,hon\rs 9 ! ,ma!matical ,tripos approv$ by ,grace ( ! ,s5ate on ! #bnd ( ,june1 #ahfh1 ,heat1 ,electricity & ,magnetism1 if n introduc$ = ! fir/ "t1 _h a mu* great] degree ( importance assign$ to !m ?an at any previ\s p]iod1 & ^! subjects w h5ce=? dem& a correspond+ am\nt ( att5tion f ! c&idates = ,ma!matical ,hon\rs4 ,! ,syndicate h limit$ _! att5tion almo/ entirely to ! "q ( provid+ public in/ruction 9 ,heat1 ,electricity & ,magnetism4 ,!y recognise ! importance & advantage ( tutorial in/ruction 9 ^! subjects 9 ! sev]al colleges1 b !y are also alive to ! great impulse giv5 to /udies ( ?is k9d1 & to ! l>ge am\nt ( additional tra9+ :i* /ud5ts may receive ?r\gh ! in/ruction ( a public ,pr(essor1 & by k ga9$ 9 a well-appo9t$ laboratory40 8,9 accordance ) ^! views1 & at an e>ly p]iod 9 _! delib]ations1 !y reque/$ ! ,pr(essors#cd ( ! ,univ]sity1 :o are engag$ 9 tea*+ ,ma!matical & ,physical ,sci5ce1 to conf] toge!r ^u ! pres5t means ( tea*+ ,exp]im5tal ,physics1 especially ,heat1 ,electricity & ,magnetism1 & to in=m !m h[ ! increas$ requirem5ts ( ! ,univ]sity 9 ?is respect c\ld be met by !m40 8,! ,pr(essors1 s consult$1 fav\r$ ! ,syndicate ) a report on ! subject1 :i* ! ,syndicate n[ beg leave to lay be=e ! ,s5ate4 ,x po9ts out h[ ! requirem5ts ( ! ,univ]sity might be 8p>tially met10 b ! ,pr(essors /ate di/9ctly t !y 8d n ?9k t !y are able to meet ! want ( an ext5sive c\rse ( lectures on ,physics treat$ z su*1 & 9 great measure exp]im5tally4 ,z ,exp]im5tal ,physics may fairly be consid]$ to come )9 ! prov9ce ( "o or m ( ! above-m5tion$ ,pr(essors1 ! ,syndicate h consid]$ :e!r n[ or at "s future "t "s arrangem5t might n be made to secure ! effective tea*+ ( ?is bran* ( sci5ce1 )\t hav+ resort to ! s]vices ( an additional ,pr(essor4 ,!y are1 h[ev]1 ( op9ion t su* an arrangem5t _c be made at ! pres5t "t1 & t ! exig5cies ( ! case may be be/ met by f\nd+ a new pr(essor%ip :i* %all t]m9ate ) ! t5ure ( (fice ( ! ,pr(essor fir/ elect$4 ,! s]vices ( a man ( ! highe/ atta9m5ts 9 sci5ce1 devot+ 8 life to public tea*+ z su* ,pr(essor1 & engag$ 9 orig9al rese>*1 w\ld be ( incalculable b5efit to ! ,univ]sity40 ,! ,report goes on to po9t out t a laboratory w\ld be necess>y1 & also app>atus4 ,x is e/imat$ t #e1jjj w\ld cov] ! co/ ( ! laboratory1 & #a1cjj ! necess>y app>atus4 ,provision is also made = a demon/rator & a laboratory assi/ant1 & ! ,report closes ) a recomm5dation t a special ,syndicate ( ,f9ance %\ld be appo9t$ to consid] ! means ( rais+ ! funds4 ,! ,pr(essors 9 _! ,report to ! ,syndicate po9t out t tea*+ 9 ,exp]im5tal ,physics is ne$$ = ! ,ma!matical ,tripos1 ! ,natural ,sci5ces ,tripos1 c]ta9 ,special exam9ations1 & ! fir/ exam9ation = ! degree ( ,m4,b4 ,x appe>$ to !m cle> t !re 0 "w = a new ,pr(essor4 ,9 ,may1 #ahfi1 ! ,f9ancial ,syndicate recomm5d$ by ! above ,report 0 appo9t$ 8to consid] ! means ( rais+ ! necess>y funds = e/abli%+ a pr(essor & demon/rator ( ,exp]im5tal ,physics1 & = provid+ build+s & app>atus requir$ = t dep>tm5t ( sci5ce1 & fur!r to consid] o!r wants ( ! ,univ]sity1 & ! s\rces f :i* ^? wants may be suppli$40 ,! ,syndicate endeav\r$ to meet ! exp5diture by inquiry f ! sev]al ,colleges :e!r !y w\ld be will+ to make contributions f _! corporate funds1 b )\t success4 8,! answ]s ( ! ,colleges indicat$ su* a want ( concurr5ce 9 any proposal to raise contributions f ! corporate funds ( ,colleges by any k9d ( direct taxation t ! ,syndicate felt oblig$ to ab&on ! notion ( obta9+ ! necess>y funds f ?is s\rce1 & accord+ly to limit ! numb] ( objects :i* !y %\ld recomm5d ! ,s5ate to accompli%40 ,ext]nal au?ority 0 necess>y be=e ! colleges w\ld submit to taxation = ,univ]sity purposes1 & x 0 left to ! ,royal ,commission ( #ahgg to c>ry into effect _m ( ! sugge/ions made by ! ,syndicate4 ,mean:ile !y cont5t$ !mselves ) recomm5d+ means = rais+ an annual /ip5d ( #ffj = ! pr(essor1 demon/rator1 & assi/ant1 & a capital sum ( #e1jjj1 or !reab\ts1 = ! exp5ses ( a build+4 ,! ,syndicate's ,report 0 issu$ 9 an am5d$ =m 9 ! ,may t]m ( #ahgj1 & be=e any decision 0 tak5 on x ! ,vice-,*ancellor1 ,dr4 ,atk9son1 on ,octob] #ac?1 #ahgj1 publi%$ 8! foll[+ munific5t (f] ( 8 grace ! ,duke ( ,devon%ire1 ! ,*ancellor ( ! ,univ]sity10 :o _h be5 *airman ( ! ,commission on ,sci5tific ,education4 8,holk] ,hall1 ,grange1 ,lanca%ire4 8,,my ,,de> ,,mr4 ,,vice-,,*ancellor1--,i h ! hon\r to address y = ! purpose ( mak+ an (f] to ! ,univ]sity1 :i*1 if y see no objection1 ,i %all be mu* oblig$ to y to submit 9 su* mann] z y may ?9k fit = ! consid]ation ( ! ,c\ncil & ! ,univ]sity4 8,i f9d 9 ! report dat$ ,febru>y #bi?1 #ahfi1 ( ! ,physical ,sci5ce ,syndicate1 recomm5d+ ! e/abli%m5t ( a ,pr(essor & ,demon/rator ( ,exp]im5tal ,physics1 t ! build+s & app>atus requir$ = ?is dep>tm5t ( sci5ce are e/imat$ to co/ #f1cjj4 8,i am desir\s to assi/ ! ,univ]sity 9 c>ry+ ?is recomm5dation into effect1 & %all accord+ly be prep>$ to provide ! funds requir$ = ! build+ & app>atus z soon z ! ,univ]sity %all h 9 o!r respects complet$ its arrangem5ts = tea*+ ,exp]im5tal ,physics1 & %all h approv$ ! plan ( ! build+4 8,i rema91 my de> ,mr4 ,vice-,*ancellor1 8,y\rs v fai?fully1 8,,devon%ire40 ,by 8 g5]\s action ! ,univ]sity 0 reliev$ f all exp5se connect$ ) ! build+4 ,a ,grace e/abli%+ a ,pr(essor%ip ( ,exp]im5tal ,physics 0 confirm$ by ! ,s5ate ,febru>y #i?1 #ahga1 & ,m>* #h? 0 fix$ = ! election4 ,mean:ile :o 0 to be ,pr(essor8 ,sir ,w4 ,?omson's "n _h be5 m5tion$1 b he1 x 0 kn[n1 w\ld n accept ! po/4 ,maxwell 0 !n appli$ to1 & at fir/ he 0 unwill+ to leave ,gl5lair4 ,pr(essor ,/okes1 ! ,hon4 ,j4 ,w4 ,/rutt 7,"l ,rayleigh71 ,mr4 ,blore ( ,tr9ity1 & o!rs wrote to him4 ,"l ,rayleigh's lett]#ce is z foll[s3 8,cambridge1 #ad? ,febru>y1 #ahga4 8,:5 ,i came "h la/ ,friday ,i f\nd ev]yone talk+ ab\t ! new pr(essor%ip1 & hop+ t y w\ld come4 ,?omson1 x seems1 has def9itely decl9$4444 ,!re is no "o "h 9 ! lea/ fit = ! po/4 ,:at is want$ by mo/ :o "k any?+ ab\t x is n s mu* a lectur] z a ma!matician :o has actual exp]i5ce 9 exp]im5t+1 & :o might direct ! en]gies ( ! y\ng] ,fell[s & ba*elors into a prop] *annel4 ,!re mu/ be _m :o w\ld be will+ to "w "u a compet5t man1 & :o1 :ile le>n+ !mselves1 w\ld mat]ially assi/ him4444 ,i hope y may be induc$ to come2 if n1 ,i don't "k :o x is to be4 ,d n tr\ble to answ] me ab\t ?is1 z ,i believe o!rs h writt5 to y ab\t x40 ,on ! #ae? ( ,febru>y1 ,maxwell wrote to ,mr4 ,blore3-- 8,i _h no int5tion ( apply+ = ! po/ :5 ,i got y\r lett]1 & ,i h none n[1 unless ,i come to see t ,i c d "s good by x40 ,! lett] cont9ues3--8,! class ( ,physical ,inve/igations1 :i* might be und]tak5 ) ! help ( m5 ( ,cambridge education1 & :i* w\ld be cr$itable to ! ,univ]sity1 dem& 9 g5]al a consid]able am\nt ( dull lab\r1 :i* may or may n be attractive to ! pupils40 ,h[ev]1 on ! #bd? ( ,febru>y1 ,mr4 ,blore wrote to ! ,electoral ,roll3-- 8,i am au?oris$ to give notice t ,mr4 ,john 7sic7 ,cl]k ,maxwell1 ,f4,r4,s41 =m]ly ,pr(essor ( ,natural ,philosophy at ,ab]de51 & at ,k+'s ,college1 ,london1 is a c&idate = ! pr(essor%ip ( ,exp]im5tal ,physics40 ,maxwell 0 elect$ )\t opposition4 ,writ+#cf to 8 wife f ,cambridge1 #bj? ,m>*1 #ahga1 he says3-- 8,!re are two p>ties ab\t ! pr(essor%ip4 ,"o wants popul> lectures1 & ! o!r c>es m = exp]im5tal "w4 ,i ?9k !re %\ld be a gradation--popul> lectures & r\gh exp]im5ts = ! masses2 real exp]im5ts = real /ud5ts2 & labori\s exp]im5ts = fir/-rate m5 l ,trott] & ,/u>t & ,/rutt40 ,:ile 9 a lett]#cg f ,gl5lair to ,c4 ,j4 ,munro1 dat$ ,m>* #ae?1 #ahga1 he writes3--8,! ,exp]im5tal ,physics at ,cambridge is n built yet1 b we are go+ to try4 ,! desid]atum is to set a ,don & a ,fre%man to obs]ve & regi/] 7say7 ! vibrations ( a magnet toge!r1 or ! ,don to turn a wat* & ! ,fre%man to obs]ve & gov]n him40 ,9 ,octob] he deliv]$ 8 ,introductory ,lecture4 ,a few quotations w %[ ! _s 9 :i* he approa*$ 8 task4 8,9 a c\rse ( ,exp]im5tal ,physics we may consid] ei!r ! ,physics or ! ,exp]im5ts z ! lead+ feature4 ,we may ei!r employ ! exp]im5ts to illu/rate ! ph5om5a ( a p>ticul> bran* ( ,physics1 or we may make "s physical rese>* 9 ord] to exemplify a p>ticul> exp]im5tal me?od4 ,9 ! ord] ( "t1 we %\ld beg91 9 ! ,lecture ,room1 ) a c\rse ( lectures on "s bran* ( ,physics aid$ by exp]im5ts ( illu/ration1 & conclude1 9 ! ,laboratory1 ) a c\rse ( exp]im5ts ( rese>*4 8,let me say a few words on ^! two classes ( exp]im5ts--,exp]im5ts ( ,illu/ration & ,exp]im5ts ( ,rese>*4 ,! aim ( an exp]im5t ( illu/ration is to ?r[ light ^u "s sci5tific idea s t ! /ud5t may be enabl$ to grasp x4 ,! circum/ances ( ! exp]im5t are s arrang$ t ! ph5om5on :i* we wi% to obs]ve or to exhibit is br\ght into prom95ce1 in/ead ( be+ obscur$ & entangl$ among o!r ph5om5a1 z x is :5 x occurs 9 ! ord9>y c\rse ( nature4 ,to exhibit illu/rative exp]im5ts1 to enc\rage o!rs to make !m1 & to cultivate 9 e way ! ideas on :i* !y ?r[ light1 =ms an important "p ( our duty4 ,! simpl] ! mat]ials ( an illu/rative exp]im5t1 & ! m famili> !y are to ! /ud5t1 ! m ?or\ghly is he likely to acquire ! idea :i* x is meant to illu/rate4 ,! educational value ( su* exp]im5ts is (t5 inv]sely proportional to ! complexity ( ! app>atus4 ,! /ud5t :o uses home-made app>atus1 :i* is always go+ wrong1 (t5 le>ns m ?an "o :o has ! use ( c>efully adju/$ in/rum5ts1 to :i* he is apt to tru/1 & :i* he d>es n take to pieces4 8,x is v necess>y t ^? :o are try+ to le>n f books ! facts ( physical sci5ce %\ld be enabl$ by ! help ( a few illu/rative exp]im5ts to recognise ^! facts :5 !y meet ) !m out ( doors4 ,sci5ce appe>s to u ) a v diff]5t aspect aft] we h f\nd out t x is n 9 lecture-rooms only1 & by means ( ! electric light project$ on a scre51 t we may witness physical ph5om5a1 b t we may f9d illu/rations ( ! highe/ doctr9es ( sci5ce 9 games & gymna/ics1 9 travell+ by l& & by wat]1 9 /orms ( ! air & ( ! sea1 & :]ev] !re is matt] 9 motion4 8,if1 !re=e1 we desire1 = our own advantage & = ! hon\r ( our ,univ]sity1 t ! ,devon%ire ,laboratory %\ld be successful1 we mu/ endeav\r to ma9ta9 x 9 liv+ union ) ! o!r organs & faculties ( our le>n$ body4 ,we %all !re=e fir/ consid] ! relation 9 :i* we /& to ^? ma!matical /udies :i* h s long fl\ri%$ among u1 :i* deal ) our own subjects1 & :i* diff] f our exp]im5tal /udies only 9 ! mode 9 :i* !y are pres5t$ to ! m9d4 8,!re is no m p[]ful me?od = introduc+ k into ! m9d ?an t ( pres5t+ x 9 z _m diff]5t ways z we c4 ,:5 ! ideas1 aft] ent]+ ?r\gh diff]5t gateways1 effect a junction 9 ! citadel ( ! m9d1 ! position !y occupy becomes impregnable4 ,opticians tell u t ! m5tal comb9ation ( ! views ( an object :i* we obta9 f /ations no fur!r ap>t ?an our two eyes is suffici5t to produce 9 our m9ds an impression ( ! solidity ( ! object se52 & we f9d t ?is impression is produc$ ev5 :5 we are aw>e t we are really look+ at two flat pictures plac$ 9 a /]eoscope4 ,x is !re=e natural to expect t ! k ( physical sci5ce obta9$ by ! comb9$ use ( ma!matical analysis & exp]im5tal rese>* w be ( a m solid1 available1 & endur+ k9d ?an t possess$ by ! m]e ma!matician or ! m]e exp]im5t]4 8,b :at w be ! effect on ! ,univ]sity if m5 pursu+ t c\rse ( read+ :i* has produc$ s _m di/+ui%$ ,wrangl]s turn aside to "w exp]im5ts8 ,w n _! att5dance at ! ,laboratory c\nt n m]ely z "t )drawn f _! m legitimate /udies1 b z ! introduction ( a di/urb+ elem5t1 ta9t+ _! ma!matical conceptions ) mat]ial imag]y1 & sapp+ _! fai? 9 ! =mul ( ! text-books8 ,besides ?is1 we h already he>d compla9ts ( ! undue ext5sion ( our /udies1 & ( ! /ra9 put ^u our que/ioni/s by ! weight ( le>n+ :i* !y try to c>ry ) !m into ! ,s5ate-,h\se4 ,if we n[ ask !m to get up _! subjects n only by books & writ+1 b at ! same "t by obs]vation & manipulation1 w !y n break d[n altoge!r8 ,! ,physical ,laboratory1 we are told1 may p]haps be useful to ^? :o are go+ out 9 ,natural ,sci5ce1 & :o d n take 9 ,ma!matics1 b to attempt to comb9e bo? k9ds ( /udy dur+ ! "t ( resid5ce at ! ,univ]sity is m ?an "o m9d c be>4 8,no d\bt !re is "s reason = ?is feel+4 ,_m ( u h already ov]come ! initial difficulties ( ma!matical tra9+4 ,:5 we n[ g on ) our /udy1 we feel t x requires ex]tion & involves fatigue1 b we are confid5t t if we only "w h>d our progress w be c]ta94 8,"s ( u1 on ! o!r h&1 may h _h "s exp]i5ce ( ! r\t9e ( exp]im5tal "w4 ,z soon z we c read scales1 obs]ve times1 focus telescopes1 & s on1 ?is k9d ( "w ceases to require any great m5tal ef=t4 ,we may1 p]haps1 tire our eyes & we>y our backs1 b we d n greatly fatigue our m9ds4 8,x is n till we attempt to br+ ! !oretical "p ( our tra9+ into contact ) ! practical t we beg9 to exp]i5ce ! full effect ( :at ,f>aday has call$ #8m5tal in]tia'--n only ! difficulty ( recognis+1 among ! concrete objects be=e u1 ! ab/ract relation :i* we h le>n$ f books1 b ! di/ract+ pa9 ( wr5*+ ! m9d away f ! symbols to ! objects1 & f ! objects back to ! symbols4 ,?is1 h[ev]1 is ! price we h to pay = new ideas4 8,b :5 we h ov]come ^! difficulties1 & successfully bridg$ ov] ! gulph betwe5 ! ab/ract & ! concrete1 x is n a m]e piece ( k t we h obta9$2 we h acquir$ ! rudim5t ( a p]man5t m5tal end[m5t4 ,:51 by a repetition ( ef=ts ( ?is k9d1 we h m fully develop$ ! sci5tific faculty1 ! ex]cise ( ?is faculty 9 detect+ sci5tific pr9ciples 9 nature1 & 9 direct+ practice by !ory1 is no long] irksome1 b becomes an unfail+ s\rce ( enjoym5t1 to :i* we return s (t5 t at la/ ev5 our c>eless ?\ghts beg9 to run 9 a sci5tific *annel4 8,our pr9cipal "w1 h[ev]1 9 ! ,laboratory mu/ be to acqua9t ourselves ) all k9ds ( sci5tific me?ods1 to comp>e !m & to e/imate _! value4 ,x w1 ,i ?9k1 be a result wor?y ( our ,univ]sity1 & m likely to be accompli%$ "h ?an 9 any private laboratory1 if1 by ! free & full discussion ( ! relative value ( diff]5t sci5tific proc$ures1 we succe$ 9 =m+ a s*ool ( sci5tific criticism & 9 assi/+ ! developm5t ( ! doctr9e ( me?od4 8,b admitt+ t a practical acqua9tance ) ! me?ods ( ,physical ,sci5ce is an ess5tial "p ( a ma!matical & sci5tific education1 we may be ask$ :e!r we are n attribut+ too mu* importance to sci5ce altoge!r z "p ( a lib]al education4 8,=tunately1 !re is no "q "h :e!r ! ,univ]sity %\ld cont9ue to be a place ( lib]al education1 or %\ld devote itself to prep>+ "y m5 = p>ticul> pr(essions4 ,h5ce1 ?\gh "s ( u may1 ,i hope1 see reason to make ! pursuit ( sci5ce ! ma9 bus9ess ( our lives1 x mu/ be "o ( our mo/ con/ant aims to ma9ta9 a liv+ connexion betwe5 our "w & ! o!r lib]al /udies ( ,cambridge1 :e!r lit]>y1 philological1 hi/orical1 or philosophical4 8,!re is a n>r[ pr(essional _s :i* may gr[ up among m5 ( sci5ce j z x does among m5 :o practise any o!r special bus9ess4 ,b surely a ,univ]sity is ! v place :]e we %\ld be able to ov]come ?is t5d5cy ( m5 to become1 z x 71 granulat$ into small worlds1 :i* are all ! m worldly = _! v smallness8 ,we lose ! advantage ( hav+ m5 ( v>i$ pursuits collect$ into "o body if we d n endeav\r to imbibe "s ( ! _s ev5 ( ^? ^: special bran* ( le>n+ is diff]5t f our own40 ,ano!r expression ( 8 views on ! position ( ,physics at ! "t w be f\nd 9 8 address to ,section ,a ( ! ,briti% ,association1 :5 ,presid5t at ! ,liv]pool meet+ ( #ahgj4 ,,*apt] ,,vi4 ,,cambridge--,,! ,,cav5di% ,,laboratory4 ,b ! laboratory 0 n yet built4 ,a ,syndicate1 ( :i* ,maxwell 0 a memb]1 0 appo9t$ to consid] ! "q ( a site1 to take pr(essional advice1 & to obta9 plans & e/imates4 ,pr(essor ,maxwell & ,mr4 ,trott] visit$ v>i\s laboratories at home & abroad = ! purpose ( asc]ta9+ ! be/ arrangem5ts4 ,mr4 ,w4 ,m4 ,fawcett 0 appo9t$ ar*itect2 ! t5d] ( ,mr4 ,john ,lov$ay1 ( ,kebwor?1 = ! build+ at a co/ ( #h1dej1 exclusive ( gas1 wat]1 & heat+1 0 accept$ 9 ,m>*1 #ahgb1 & ! build+#ch 0 begun dur+ ! summ]4 ,9 ! meantime ,maxwell began to lecture1 f9d+ a home :]e he c\ld4 8,lectures beg9 #bd?10 he writes f ,gl5lair1 ,octob] #ai?1 #ahgb4 8,laboratory ris+1 ,i he>1 b ,i h no place to erect my *air1 b move ab\t l ! cuckoo1 deposit+ my notions 9 ! ,*emical ,lecture-room #a/ t]m2 9 ! ,botanical 9 ,l5t1 & 9 ,comp>ative ,anatomy 9 ,ea/]40 ,x 0 n till ,june1 #ahgd1 t ! build+ 0 complete1 & on ! #af? ! ,*ancellor =mally pres5t$ 8 gift ( ! ,cav5di% ,laboratory to ! ,univ]sity4 ,9 ! correspond5ce previ\s to ?is "t x 0 spok5 ( z ! ,devon%ire ,laboratory4 ,! "n ,cav5di% commemorat$ ! "w ( ! great physici/ ( a c5tury e>li]1 ^: writ+s ,maxwell 0 %ortly to edit1 z well z ! g5]osity ( ! ,*ancellor4 ,9 _! lett] ( ?anks to ! ,duke ( ,devon%ire ! ,univ]sity write3-- 8,unde v]o conv5tius pot]at illis artibus succurri quam e tua domo qu 9 ipsis jam pridem incl>u]at4 ,notum e/ ,h5ricum ,cav5di% quem secutus e/ ,c\lombius primum ita docuisse1 qu sit vis electrica ut eam num]orum modulis illu/r>et2 adhibitis rationibus quas hodie v]as esse con/at40 ,& !y sugge/ ! "n z suitable = ! build+4 ,to ?is ! ,*ancellor repli$1 aft] ref]r+ to ! "w ( ,h5ry ,cav5di%3 8,quod pono 9 (fic9 ips nuncup& nom5 ejus commemor>e dignati sitis1 id grato animo accepi40 ,! build+ _h co/ f> m ?an ! orig9al e/imate1 b ! ,*ancellor's g5]osity 0 n limit$1 & on ,july #ba/1 #ahgd1 he wrote to ! ,vice-,*ancellor3-- 8,x is my wi% to provide all in/rum5ts = ! ,cav5di% ,laboratory :i* ,pr(essor ,maxwell may consid] to be imm$iately requir$1 ei!r 9 8 lectures or o!rwise40 ,maxwell prep>$ a li/1 b expla9$ :ile do+ x t "t & ?\ght 7 necess>y to secure ! be/ =m ( in/rum5ts2 & he cont9ues1 writ+ to ! ,vice-,*ancellor3 8,i ?9k ! ,duke fully und]/ood f :at ,i said to him t to furni% ! ,laboratory w be a matt] ( sev]al ye>s' duration4 ,i %all consid] myself1 h[ev]10 he says1 8at lib]ty to contribute to ! ,laboratory any in/rum5ts :i* ,i h _h con/ruct$ 9 =m] ye>s1 & :i* may be f\nd /ill useful1 & also f "t to "t to procure o!rs = special rese>*es40 ,9 #ahgg 9 8 annual report ,pr(essor ,maxwell ann\nc$ t ! ,*ancellor#ci _h n[ 8complet$ 8 gift to ! ,univ]sity by furni%+ ! ,cav5di% ,laboratory ) app>atus suit$ to ! pres5t /ate ( sci5ce40 ,! /ock ( app>atus1 h[ev]1 0 /ill small1 al?\gh ,maxwell 9 ! mo/ g5]\s mann] himself sp5t l>ge sums 9 add+ to x2 = ! ,pr(essor 0 mo/ p>ticul> 9 procur+ only exp5sive in/rum5ts by ! be/ mak]s1 ) su* additional improvem5ts z he c\ld himself sugge/4 ,9 ,m>*1 #ahgd1 a ,demon/rator%ip ( ,physics _h be5 e/abli%$1 & ,mr4 ,g>nett ( ,/4 ,john's ,college 0 appo9t$4 ,"w began 9 ! laboratory 9 ,octob]1 #ahgd4 ,at fir/ ! numb] ( /ud5ts 0 small4 ,only sev5te5 names appe> 9 ! ,natural ,sci5ces ,tripos#dj li/ = #ahgd1 & few ( ^? did ,physics4 ,! fe> allud$ to by ! ,pr(essor 9 8 introductory lecture1 t m5 read+ = ! ,ma!matical ,tripos w\ld n f9d "t = att5dance at ! laboratory1 0 ju/ifi$4 ,"o ( ! weaknesses ( our ,cambridge plan has be5 ! divorce betwe5 ,ma!matics & exp]im5tal "w1 enc\rag$ by our sy/em ( exam9ations4 ,exp]im5tal k is suppos$ n to be ne$$ = ! ,ma!matical ,tripos2 ! ,ma!matics p]mitt$ 9 ! ,natural ,sci5ces ,tripos are v simple2 ?us x came ab\t t few m5 :ile read+ = ! ,ma!matical ,tripos att5d$ ! laboratory1 & ?is un=tunate result 0 int5sifi$ by ! action ( ! ,univ]sity 9 #ahgg-gh1 :5 ! regulations = ! ,ma!matical ,tripos 7 aga9 alt]$4#da ,/ill !re 7 pupils eag] & will+ to "w1 ?\gh !y 7 *iefly m5 :o _h already tak5 _! ,b4,a4 degree1 & :o wi%$ to cont9ue ,physical read+ & rese>*1 ev5 ?\gh x involv$ 8a consid]able am\nt ( dull lab\r n altoge!r attractive40 ,my own "w !re began 9 #ahgf1 & x may be int]e/+ if ,i recall my rem9isc5ces ( t "t4 ,! fir/ exp]im5ts ,i c recollect relat$ to ! measurem5t ( electrical resi/ance4 ,i well rememb] ,maxwell expla9+ ! pr9ciple ( ,:eat/one's bridge1 & my own wi% at ! "t t ,i _h come to ! laboratory be=e ! ,tripos1 in/ead ( aft]w>ds4 ,"l ,rayleigh _h1 dur+ ! exam9ation1 set an easy "q :i* ,i fail$ to d = want ( "s slight exp]im5tal k1 & ! fir/ few words ( ,maxwell's talk %[$ me ! solution4 ,i did n att5d 8 lectures regul>ly--!y 7 giv51 ,i ?9k1 at an h\r :i* ,i 0 oblig$ to devote to tea*+2 besides1 !re 0 8 book1 ! 8,electricity & ,magnetism10 into :i* ,i _h j dipp$ be=e ! ,tripos1 to "w at4 ,*ry/al & ,saund] 7 !n busy at _! v]ification ( ,ohm's law4 ,!y 7 us+ a numb] ( ! ,?omson =m ( tray ,daniell's cells1 & ,maxwell 0 anxi\s = te/s ( v>i\s k9ds to be made on ^! cells2 ^! ,i und]took1 & sp5t "s "t ov] v>i\s simple measurem5ts on !m4 ,he !n set me to "w at "s ( ! prop]ties ( a /ratifi$ dielectric1 consi/+1 if ,i rememb] rightly1 ( %eets ( p>aff9 pap] & mica4 ,by ?is means ,i became acqua9t$ ) v>i\s pieces ( app>atus4 ,!re 7 no regul> classes & no set drill ( demon/rations arrang$ = exam9ation purposes2 ^! came lat]4 ,9 ,maxwell's "t ^? :o wi%$ to "w _h ! use ( ! laboratory & assi/ance & help f him1 b !y 7 left pretty mu* to !mselves to f9d out ab\t ! app>atus & ! be/ me?ods ( us+ x4 ,r lat] ?an ?is ,s*u/] came & did "s ( 8 spectroscope "w4 ,j4 ,e4 ,h4 ,gordon 0 busy ) ! prelim9>y obs]vations = 8 det]m9ation ( ,v]det's con/ant1 & ,niv5 _h v>i\s electrical exp]im5ts on h&2 :ile ,flem+ 0 at "w on ! ,b4 ,a4 resi/ance coils4 ,my own ta/es lay 9 ! direction ( optics4 ,maxwell 0 anxi\s t ,i %\ld inve/igate ! prop]ties ( c]ta9 cry/als4 ,i ?9k !y 7 ! *lorate ( pota% cry/als1 ab\t :i* ,/okes & ,rayleigh h s9ce writt52 b ^! cry/als 7 to be gr[n1 a sl[ process :i* w\ld1 he suppos$1 take ye>s2 & z ,i wi%$ to produce a diss]tation = ! ,tr9ity ,fell[%ip exam9ation 9 #ahgg1 t "w _h to be laid aside4 ,ev5tually ,i select$ z a subject ! =m ( ! wave surface 9 a biaxial cry/al1 & set to "w 9 a room assign$ to me4 ,! ,pr(essor us$ to come 9 on mo/ days to see h[ ,i 0 gett+ on4 ,g5]ally he br\ght 8 dog1 :i* sometimes 0 %ut up 9 ! next room :ile he w5t to college4 ,dogs 7 n all[$ 9 college1 & ,maxwell _h an amus+ way ( describ+ h[ ,toby once w&]$ into ,tr9ity1 & by "s doggi% in/9ct discov]$ imm$iately1 to 8 int5se amazem5t1 t he 0 9 a place :]e no dogs _h be5 s9ce ! college 04 ,toby 0 n always quiet 9 8 ma/]'s abs5ce1 & 8 pres5ce 9 ! next room 0 some:at di/urb+4 ,:5 difficulties occurr$ ,maxwell 0 always ready to li/54 ,(t5 ! answ] did n come at once1 b x always did come aft] a little "t4 ,i rememb] "o day1 :5 ,i 0 9 a s]i\s dilemma1 ,i told him my long tale1 & he said3-- 8,well1 ,*ry/al has be5 talk+ to me1 & ,g>nett & ,s*u/] h be5 ask+ que/ions1 & all ?is has =m$ a good ?ick cru/ r\nd my bra94 ,:at y h said w take "s "t to soak ?r\gh1 b we w see ab\t x40 ,9 a few days he came back )--8,i h be5 ?9k+ ov] :at y said ! o!r day1 & if y d s-&-s x w be all "r40 ,my diss]tation 0 ref]r$ to him1 & on ! day ( ! election1 :5 return+ to ,cambridge = ! admission1 ,i met him at ,blet*ley /ation1 & well rememb] 8 k9d congratulations & words ( w>m enc\ragem5t4 ,= ! next ye> & a half ,i 0 work+ regul>ly at ! laboratory & saw him almo/ daily dur+ t]m "t4 ,( ^! la/ ye>s !re really is b little to tell4 ,8 own sci5tific "w w5t on4 ,! 8,electricity & ,magnetism0 0 writt5 mo/ly at ,gl5lair4 ,ab\t ! "t ( 8 return to ,cambridge1 9 ,octob]1 #ahgb1 he writes#db to ,lewis ,campbell3-- 8,i am cont9ually engag$ 9 /irr+ up ! ,cl>5don ,press1 b !y h be5 tol]ably regul> = two mon?s4 ,i f9d n9e %eets 9 ?irte5 weeks is _! av]age4 ,tait gives me great help 9 detect+ absurdities4 ,i am gett+ conv]t$ to quat]nions1 & h put "s 9 my book40 ,! book 0 publi%$ 9 #ahgc4 ,! ,text-book ( ,heat 0 writt5 dur+ ! same p]iod1 :ile 8,matt] & ,motion10 8a small book on a great subject10 0 publi%$ 9 #ahgf4 ,9 #ahgc & #ahgd he 0 "o ( ! exam9]s = ! ,natural ,sci5ces ,tripos1 & 9 #ahgc he 0 ! fir/ additional exam9] = ! ,ma!matical ,tripos1 9 accordance ) ! s*eme :i* he _h done s mu* to promote 9 #ahfh4 ,_m ( 8 %ort] pap]s 7 writt5 ab\t ! same "t4 ,! n9? edition ( ! ,encyclopdia ,britannica 0 be+ publi%$1 & ,pr(essor ,baynes _h enli/$ 8 aid 9 ! "w4 ,! articles 8,atom10 8,attraction10 8,capill>y ,action10 8,con/itution ( ,bodies10 8,diffusion10 8,e!r10 8,f>aday10 & o!rs are by him4 ,he also wrote a numb] ( pap]s = ,nature4 ,"s ( ^! are reviews ( books or acc\nts ( sci5tific m51 su* z ! notices ( ,f>aday & ,helmholtz1 :i* appe>$ ) _! portraits2 o!rs aga9 are orig9al contributions to sci5ce4 ,among ! latt] _m h ref]5ce to ! molecul> con/itution ( bodies4 ,two lectures--! fir/ on 8,molecules10 deliv]$ be=e ! ,briti% ,association at ,brad=d 9 #ahgc2 ! second on ! 8,dynamical ,evid5ce ( ! ,molecul> ,con/itution ( ,bodies10 deliv]$ be=e ! ,*emical ,society 9 #ahge--7 ( special importance4 ,! clos+ s5t5ces ( ! fir/ lecture h be5 (t5 quot$4 ,!y run z foll[3-- 8,9 ! heav5s we discov] by _! light1 & by _! light alone1 />s s di/ant f ea* o!r t no mat]ial ?+ c ev] h pass$ f "o to ano!r2 & yet ?is light1 :i* is to u ! sole evid5ce ( ! exi/5ce ( ^! di/ant worlds1 tells u also t ea* ( !m is built up ( molecules ( ! same k9ds z ^? :i* we f9d on e>?4 ,a molecule ( hydrog51 = example1 :e!r 9 ,sirius or 9 ,arcturus1 executes its vibrations 9 precisely ! same "t4 8,ea* molecule !re=e ?r\gh\t ! univ]se be>s impress$ ^u x ! /amp ( a metric sy/em1 z di/9ctly z does ! metre ( ! ,ar*ives at ,p>is1 or ! d\ble royal cubit ( ! temple ( ,k>nac4 8,no !ory ( evolution c be =m$ to acc\nt = ! simil>ity ( molecules1 = evolution necess>ily implies cont9u\s *ange1 & ! molecule is incapable ( gr[? or decay1 ( g5]ation or de/ruction4 8,none ( ! processes ( ,nature1 s9ce ! "t :5 ,nature began1 h produc$ ! slighte/ diff]5ce 9 ! prop]ties ( any molecule4 ,we are !re=e unable to ascribe ei!r ! exi/5ce ( ! molecules or ! id5tity ( _! prop]ties to any ( ! causes :i* we call natural4 8,on ! o!r h&1 ! exact equality ( ea* molecule to all o!rs ( ! same k9d gives x1 z ,sir ,john ,h]s*el has well said1 ! ess5tial "* ( a manufactur$ article1 & precludes ! idea ( its be+ et]nal & self-exi/5t4 8,?us we h be5 l$ along a /rictly sci5tific pa?1 v ne> to ! po9t at :i* ,sci5ce mu/ /op--n t ,sci5ce is deb>r$ f /udy+ ! int]nal me*anism ( a molecule :i* %e _c take to pieces any m ?an f inve/igat+ an organism :i* %e _c put toge!r4 ,b 9 trac+ back ! hi/ory ( matt]1 ,sci5ce is arre/$ :5 %e assures h]self1 on ! "o h&1 t ! molecule has be5 made1 &1 on ! o!r1 t x has n be5 made by any ( ! processes we call natural4 8,sci5ce is incompet5t to reason ^u ! creation ( matt] itself out ( no?+4 ,we h rea*$ ! utmo/ limits ( our ?9k+ faculties :5 we h admitt$ t because matt] _c be et]nal & self-exi/5t1 x mu/ h be5 creat$4 8,x is only :5 we contemplate1 n matt] 9 itself1 b ! =m 9 :i* x actually exi/s1 t our m9d f9ds some?+ on :i* x c lay hold4 8,t matt]1 z su*1 %\ld h c]ta9 fundam5tal prop]ties1 t x %\ld exi/ 9 space & be capable ( motion1 t its motion %\ld be p]si/5t1 & s on1 are tru?s :i* may1 = any?+ we "k1 be ( ! k9d :i* metaphysicians call necess>y4 ,we may use our k ( su* tru?s = purposes ( d$uction1 b we h no data = speculat+ z to _! orig94 8,b t !re %\ld be exactly s mu* matt] & no m 9 e molecule ( hydrog5 is a fact ( a v diff]5t ord]4 ,we h "h a p>ticul> di/ribution ( matt]--a collocation1 to use ! expression ( ,dr4 ,*alm]s1 ( ?+s :i* we h no difficulty 9 imag9+ to h be5 arrang$ o!rwise4 8,! =m & dim5sions ( ! orbits ( ! planets1 = in/ance1 are n det]m9$ by any law ( nature1 b dep5d ^u a p>ticul> collocation ( matt]4 ,! same is ! case ) respect to ! size ( ! e>?1 f :i* ! /&>d ( :at is call$ ! metrical sy/em has be5 d]iv$4 ,b ^! a/ronomical & t]re/rial magnitudes are f> inf]ior 9 sci5tific importance to t mo/ fundam5tal ( all /&>ds :i* =ms ! base ( ! molecul> sy/em4 ,natural causes1 z we "k1 are at "w :i* t5d to modify1 if !y d n at l5g? de/roy1 all ! arrangem5ts & dim5sions ( ! e>? & ! :ole sol> sy/em4 ,b ?\gh 9 ! c\rse ( ages cata/rophes h occurr$ & may yet occur 9 ! heav5s1 ?\gh anci5t sy/ems may be dissolv$ & new sy/ems evolv$ out ( _! ru9s1 ! molecules out ( :i* ^! sy/ems are built--! f\ndation /ones ( ! mat]ial univ]se--rema9 unbrok5 & unworn4 ,!y cont9ue ?is day z !y 7 creat$--p]fect 9 numb] & measure & weight2 & f ! ineffaceable *>act]s impress$ on !m we may le>n t ^? aspirations aft] accuracy 9 measurem5t1 & ju/ice 9 action1 :i* we reckon among our noble/ attributes z m51 are ours because !y are ess5tial con/itu5ts ( ! image ( ,him :o 9 ! beg9n+ creat$1 n only ! heav5 & ! e>?1 b ! mat]ials ( :i* heav5 & e>? consi/40 ,?is 0 criticis$ 9 ,nature by ,mr4 ,c4 ,j4 ,munro1 & at a lat] "t by ,clif=d 9 "o ( 8 essays4 ,"s correspond5ce ) ! ,bi%op ( ,gl\ce/] & ,bri/ol on ! au?ority = ! comp>ison ( molecules to manufactur$ articles is giv5 by ,pr(essor ,campbell1 & 9 x ,maxwell po9ts out t ! latt] "p ( ! article 8,atom0 9 ! ,encyclopdia is int5d$ to meet ,mr4 ,munro's criticism4 ,9 #ahgd ! ,briti% ,association met at ,belfa/1 "u ! presid5cy ( ,tyndall4 ,maxwell 0 pres5t1 & publi%$ aft]w>ds 9 ,blackwood's ,magaz9e an amus+ p>aphrase ( ! presid5t's address4 ,?is1 ) "s o!r v]ses writt5 at ab\t ! same "t1 may be quot$ "h4 ,pr(essor ,campbell has collect$ a numb] ( v]ses writt5 by ,maxwell at v>i\s times1 :i* illu/rate 9 an admirable mann] bo? ! grave & ! gay side ( 8 "*4 ,,briti% ,,association1 #ahgd4 ,notes ( ! ,presid5t's ,address4 ,9 ! v beg9n+s ( sci5ce1 ! p>sons1 :o manag$ ?+s !n1 ,be+ h&y ) hamm] & *isel1 made gods 9 ! lik5ess ( m52 ,till comm]ce arose1 & at l5g? "s m5 ( exceptional p[] ,supplant$ bo? demons & gods by ! atoms1 :i* la/ to ?is h\r4 ,yet !y did n aboli% ! gods1 b !y s5t !m well out ( ! way1 ,) ! r>e/ ( nect> to dr9k1 & blue fields ( no?+ to sway4 ,f no?+ comes no?+1 !y told u--naught happ5s by *ance1 b by fate2 ,!re is no?+ b atoms & void1 all else is m]e :ims out ( date6 ,!n :y %\ld a man curry fav\r ) be+s :o _c exi/1 ,to compass "s petty promotion 9 nebul\s k+doms ( mi/8 ,b n by ! rays ( ! sun1 nor ! glitt]+ %afts ( ! day1 ,mu/ ! fe> ( ! gods be dispell$1 b by words1 & _! wond]ful play4 ,s tread+ a pa? all untrod1 ! poet-philosoph] s+s ,( ! se$s ( ! mighty _w--! fir/-beg9n+s ( ?+s2 ,h[ freely he scatt]s 8 atoms be=e ! beg9n+ ( ye>s2 ,h[ he clo!s !m ) =ce z a g>m5t1 ^? small incompressible sph]es6 ,nor yet does he leave !m h>d-he>t$--he d[]s !m ) love & ) hate1 ,l sph]ical small ,briti% ,asses 9 inf9itesimal /ate2 ,till j z t liv+ ,plato1 :om =eign]s nickname ,plateau1#dc ,drops oil 9 8 :isky-&-wat] 7= =eign]s sweet5 x s72 ,ea* drop keeps ap>t f ! o!r1 enclos$ 9 a flexible sk91 ,till t\*$ by ! g5tle emotion evolv$ by ! prick ( a p93 ,?us 9 atoms a simple collision excites a s5sational ?rill1 ,evolv$ ?r\gh all sorts ( emotion1 z s5se1 und]/&+1 & w 7,= by lay+ _! heads all toge!r1 ! atoms1 z c\ncillors d1 ,may comb9e to express an op9ion to e "o ( !m new74 ,!re is nobody "h1 ,i %\ld say1 has felt true indignation at all1 ,till an indignation meet+ is held 9 ! ,ul/] ,hall2 ,!n ga!rs ! wave ( emotion1 !n noble feel+s arise1 ,till y all pass a resolution :i* takes e man by surprise4 ,?us ! pure elem5t>y atom1 ! unit ( mass & ( ?\ght1 ,by =ce ( m]e juxtaposition to life & s5sation is br\ght2 ,s1 d[n ?r\gh untold g5]ations1 transmission ( /ructureless gorms ,enables our race to inh]it ! ?\ghts ( bea/s1 fi%es1 & worms4 ,we hon\r our fa!rs & mo!rs1 gr&fa!rs & gr&mo!rs too2 ,b h[ %all we hon\r ! vi/a ( ance/ors n[ 9 our view8 ,fir/1 !n1 let u hon\r ! atom1 s lively1 s wise1 & s small2 ,! atomi/s next let u praise1 ,epicurus1 ,lucretius1 & all4 ,let u damn ) fa9t praise ,bi%op ,butl]1 9 :om _m atoms comb9$ ,to =m t rem>kable /ructure x pleas$ him to call--8 m9d4 ,la/1 praise we ! noble body to :i*1 = ! "t1 we belong1 ,ere yet ! swift :irl ( ! atoms has hurri$ u1 ru?less1 along1 ,! ,briti% ,association--l ,levia?an wor%ipp$ by ,hobbes1 ,! inc>nation ( wisdom1 built up ( our witless nobs1 ,:i* w c>ry on endless discussions :5 ,i1 & probably y1 ,h melt$ 9 inf9ite azure--9 ,engli%1 till all is blue4 ,,molecul> ,,evolution4 ,belfa/1 #ahgd4 ,at q unc]ta9 times & places1 ,! atoms left _! heav5ly pa?1 ,& by =tuit\s embraces ,eng5d]$ all t be+ ha?4 ,& ?\gh !y seem to cl+ toge!r1 ,& =m 8associations0 "h1 ,yet1 soon or late1 !y bur/ _! te!r1 ,& ?r\gh ! dep?s ( space c>e]4 ,s we :o sat1 oppress$ ) sci5ce1 ,z ,briti% ,asses1 wise & grave1 ,are n[ trans=m$ to wild ,r$ ,lions1#dd ,z r\nd our prey we ramp & rave4 ,?us1 by a swift metamorphsis1 ,wisdom turns wit1 & sci5ce joke1 ,nons5se is inc5se to our noses1 ,= :5 ,r$ ,lions speak !y smoke4 ,hail1 ,nons5se6 dry nurse ( ,r$ ,lions1#de ,f !e ! wise _! wisdom le>n2 ,f !e !y cull ^? tru?s ( sci5ce1 ,:i* into !e aga9 !y turn4 ,:at comb9ations ( ideas ,nons5se alone c wisely =m6 ,:at sage has half ! p[] t %e has1 ,to take ! t[]s ( ,tru? by /orm8 ,yield1 !n1 ye rules ( rigid reason6 ,dissolve1 ?\ too1 too solid s5se6 ,melt into nons5se = a season1 ,!n 9 "s nobl] =m cond5se4 ,soon1 all too soon1 ! *illy morn+ ,?is fl[ ( s\l w cry/allise2 ,!n ^? :o ,nons5se n[ are scorn+ ,may le>n1 too late1 :]e wisdom lies4 ,,to ,,! ,,committee ,,( ,,! ,,cayley ,,portrait ,,fund4 #ahgd4 ,o wret*$ race ( m51 to space conf9$6 ,:at hon\r c ye pay to him1 ^: m9d ,to t :i* lies beyond ha? p5etrat$8 ,! symbols he ha? =m$ %all s\nd 8 praise1 ,& lead him on ?r\gh unimag9$ ways ,to conque/s new1 9 worlds n yet creat$4 ,fir/1 ye ,det]m9ants6 9 ord]$ r[ ,& massive column rang$1 be=e him g1 ,to =m a phalanx = 8 safe protection4 ,ye p[]s ( ! n? roots ( -#a6 ,ar\nd 8 head 9 ceaseless#df cycles run1 ,z unembodi$ spirits ( direction4 ,& y1 ye undevelopable scrolls6 ,above ! ho/ wave y\r emblazon$ rolls1 ,rul$ = ! record ( 8 bright inv5tions4 ,ye cubic surfaces6 by ?rees & n9es ,draw r\nd 8 camp y\r sev5-&-tw5ty l9es-- ,! seal ( ,solomon 9 ?ree dim5sions4 ,m>* on1 symbolic ho/6 ) /ep sublime1 ,up to ! flam+ b\nds ( ,space & ,"t6 ,!re pause1 until by ,dick9son depict$1 ,9 two dim5sions1 we ! =m may trace ,( him ^: s\l1 too l>ge = vulg> space1 ,9 n dim5sions fl\ri%$ unre/rict$4 ,,9 ,,memory ,,( ,,edw>d ,,wilson1 ,:o rep5t$ ( :at 0 9 8 m9d to write aft] section4 ,,rigid ,,body 7s+s74 ,,g9 a body meet a body ,fly9' ?r\gh ! air1 ,g9 a body hit a body1 ,w x fly8 & :]e8 ,ilka impact has its measure1 ,ne'er a ane hae ,i2 ,yet a' ! lads !y measure me1 ,or1 at lea/1 !y try4 ,g9 a body meet a body ,altoge!r free1 ,h[ !y travel aft]w>ds ,we d n always see4 ,ilka problem has its me?od ,by analytics high2 ,= me1 ,i k5 na ane o' !m1 ,b :at ! waur am ,i8 ,ano!r task1 :i* occupi$ mu* "t1 f #ahgd to #ahgi1 0 ! edition ( ! works ( ,h5ry ,cav5di%4 ,cav5di%1 :o 0 great-uncle to ! ,*ancellor1 _h publi%$ only two electrical pap]s1 b he _h left "s tw5ty packets ( manuscript on ,ma!matical & ,exp]im5tal ,electricity4 ,^! 7 plac$ 9 ,maxwell's h&s 9 #ahgd by ! ,duke ( ,devon%ire4 ,niv51 9 8 preface to ! collect$ pap]s deal+ ) ?is book1 writes ?us3-- 8,?is "w1 publi%$ 9 #ahgi1 has _h ! effect ( increas+ ! reputation ( ,cav5di%1 disclos+ z x does ! unsuspect$ advances :i* t acute physici/ _h made 9 ! ,!ory ( ,electricity1 especially 9 ! measurem5t ( electrical quantities4 ,! "w is enri*$ by a v>iety ( valuable notes1 9 :i* ,cav5di%'s views & results are exam9$ by ! light ( mod]n !ory & me?ods4 ,especially valuable are ! me?ods appli$ to ! det]m9ation ( ! electrical capacities ( conductors & cond5s]s1 a subject 9 :i* ,cav5di% himself %[$ consid]able skill bo? ( a ma!matical & exp]im5tal "*4 8,! importance ( ! task und]tak5 by ,maxwell 9 connection ) ,cav5di%'s pap]s w be und]/ood f ! foll[+ extract f 8 introduction to !m3-- 8#8,x is some:at difficult to acc\nt = ! fact t ?\gh ,cav5di% _h prep>$ a complete description ( 8 exp]im5ts on ! *>ges ( bodies1 & _h ev5 tak5 ! tr\ble to write out a fair copy1 & ?\gh all ?is seems to h be5 done be=e #aggd1 & he cont9u$ to make exp]im5ts 9 electricity till #agha1 & liv$ on till #ahaj1 he kept 8 manuscript by him & nev] publi%$ x4 8#8,cav5di% c>$ m = inve/igation ?an = publication4 ,he w\ld und]take ! mo/ labori\s rese>*es 9 ord] to cle> up a difficulty :i* no "o b himself c\ld appreciate or 0 ev5 aw>e (1 & we _c d\bt t ! result ( 8 enquiries1 :5 successful1 gave him a c]ta9 degree ( satisfaction4 ,b x did n excite 9 him t desire to communicate ! discov]y to o!rs1 :i* 9 ! case ( ord9>y m5 ( sci5ce g5]ally ensures ! publication ( _! results4 ,h[ completely ^! rese>*es ( ,cav5di% rema9$ unkn[n to o!r m5 ( sci5ce is %[n by ! ext]nal hi/ory ( electricity4' 8,x w probably be ?\ght a matt] ( "s difficulty to place oneself 9 ! position ( a physici/ ( a c5tury ago1 & to asc]ta9 ! exact be>+ ( 8 exp]im5ts4 ,b ,maxwell ent]$ ^u ?is und]tak+ ) ! utmo/ en?usiasm1 & succe$$ 9 id5tify+ himself ) ,cav5di%'s me?ods4 ,he %[$ t ,cav5di% _h really anticipat$ sev]al ( ! discov]ies 9 electrical sci5ce :i* h be5 made s9ce 8 "t4 ,cav5di% 0 ! fir/ to =m ! conception ( & to measure ,electro/atic ,capacity & ,specific ,inductive ,capacity2 he also anticipat$ ,ohm's law40 ,dur+ ! la/ ye>s ( 8 life ,mrs4 ,maxwell _h a s]i\s & prolong$ illness1 & ,maxwell's "w 0 mu* increas$ by 8 duties z sick nurse4 ,on "o occasion he did n sleep 9 a b$ = ?ree weeks1 b conduct$ 8 lectures & exp]im5ts at ! laboratory z usual4 ,ab\t ?is "t "s ( ^? :o _h be5 8,apo/les0 9 #ahec-eg reviv$ ! habit ( meet+ toge!r = discussion4 ,! club1 :i* includ$ ,pr(essors ,lightfoot1 ,hort & ,we/cott1 0 *ri/5$ ! 8,eranus10 & ?ree ( ,maxwell's contributions to x h be5 pres]v$ & are pr9t$ by ,pr(essor ,campbell4 ,aft] ! ,cav5di% pap]s 7 f9i%$1 ,maxwell _h m "t = 8 own orig9al rese>*es1 & two important pap]s 7 publi%$ 9 #ahgi4 ,! "o on 8,/resses 9 ,r>efi$ ,gases aris+ f ,inequalities ( ,temp]ature0 0 pr9t$ 9 ! ,royal ,society's ,transactions1 & deals ) ! ,!ory ( ! ,radiomet]2 ! o!r on 8,boltzmann's ,!orem0 appe>s 9 ! ,transactions ( ! ,cambridge ,philosophical ,society4 ,9 ! previ\s ye> he _h deliv]$ ! ,r$e lecture on 8,! ,telephone40 ,he also began to prep>e a second edition ( 8,electricity & ,magnetism40 ,8 heal? gave way dur+ ! ,ea/] t]m ( #ahgi2 inde$ = two ye>s previ\sly he _h be5 tr\bl$ ) dyspeptic symptoms1 b _h consult$ no "o on ! subject4 ,he left ,cambridge z usual 9 ,june1 hop+ t he w\ld quickly recov] at ,gl5lair1 b he grew worse in/ead4 ,9 ,octob] he 0 told by ,dr4 ,s&]s ( ,ed9burgh t he _h n a mon? to live4 ,he return$ to ,cambridge 9 ord] to be "u ! c>e ( ,dr4 ,paget1 :o 0 able 9 "s measure to relieve 8 mo/ sev]e suff]+ b ! disease1 ( :i* 8 "m _h di$ at ! same age1 cont9u$ its progress1 & he di$ on ,novemb] #e?4 ,8 "o c>e dur+ 8 la/ illness 0 = ^? :om he left beh9d4 ,mrs4 ,maxwell 0 an invalid dep5d5t on him = ev]y?+1 & ! ?\ght ( h] helplessness 0 ! "o ?+ :i* 9 ^! la/ days tr\bl$ him4 ,a fun]al s]vice took place 9 ! *apel at ,tr9ity ,college1 & aft]w>ds 8 rema9s 7 convey$ to ,scotl& & int]r$ 9 ! family bury+-place at ,corsock1 ,kirkcudbright4 ,a memorial edition ( 8 works 0 issu$ by ! ,cambridge ,univ]sity ,press 9 #ahij4 ,a portrait by ,l[es ,dick9son hangs 9 ! hall ( ,tr9ity ,college1 & !re is a bu/ by ,boehm 9 ! laboratory4 ,aft] 8 dea? ,mrs4 ,maxwell gave 8 sci5tific libr>y to ! ,cav5di% ,laboratory1 & on h] dea? %e left a sum ( ab\t #f1jjj to f\nd a s*ol>%ip 9 ,physics1 to be held at ! laboratory4 99 99 99 99 99 ,! prec$+ pages conta9 "s acc\nt ( ,cl]k ,maxwell's life z a man ( sci5ce4 ,8 "* _h o!r sides1 & any life ( him w\ld be incomplete )\t "s brief ref]5ce to ^!4 ,8 lett]s to 8 wife & to o!r intimate fri5ds %[ ?r\gh\t 8 life ! dep? ( 8 religi\s convictions4 ,! high purpose evid5c$ 9 ! pap] giv5 to ! pres5t ,dean ( ,cant]bury :5 leav+ ,cambridge1 animat$ him cont9ually1 & appe>s f "t to "t 9 8 writ+s4 ,! /ud5t's ev5+ hymn1 compos$ 9 #ahec :5 /ill an und]graduate1 expresses ! same feel+s-- ,?r\gh ! creatures ,?\ ha/ made ,%[ ! brightness ( ,?y glory1 ,be et]nal tru? display$ ,9 _! sub/ance transitory1 ,till gre5 e>? & ocean ho>y1 ,massy rock & t5d] blade1 ,tell ! same un5d+ /ory1 8,we are ,tru? 9 =m array$40 ,tea* me s ,?y works to read ,t my fai?1 new /r5g? accru+1 ,may f _w to _w proce$1 ,wisdom's fruitful se>* pursu+1 ,till ,?y brea? my m9d imbu+1 ,i proclaim ! et]nal cre$1 ,(t ! glori\s !me r5ew+1 ,god our ,"l is ,god inde$4 ,8 views on ! relation ( ,sci5ce to ,fai? are giv5 9 8 lett]#dg to ,bi%op ,ellicott already ref]r$ to-- 8,b ,i %\ld be v sorry if an int]pretation f\nd$ on a mo/ conjectural sci5tific hypo!sis 7 to get fa/5$ to ! text 9 ,g5esis1 ev5 if by s do+ x got rid ( ! old /atem5t ( ! comm5tators :i* has long ceas$ to be intelligible4 ,! rate ( *ange ( sci5tific hypo!sis is naturally mu* m rapid ?an t ( ,biblical int]pretations1 s t if an int]pretation is f\nd$ on su* an hypo!sis1 x may help to keep ! hypo!sis above gr\nd long aft] x ought to be buri$ & =gott54 8,at ! same "t ,i ?9k t ea* individual man %\ld d all he c to impress 8 own m9d ) ! ext5t1 ! ord]1 & ! unity ( ! univ]se1 & %\ld c>ry ^! ideas ) him z he reads su* passages z ! #a/ *apt] ( ! ,epi/le to ,colossians 7see #8,lightfoot on ,colossians1' p4 #ahb71 j z enl>g$ conceptions ( ! ext5t & unity ( ! _w ( life may be ( s]vice to u 9 read+ ,psalm viii41 ,heb4 ii4 #f1 etc40 ,& aga9 9 8 lett]#dh to ! secret>y ( ! ,victoria ,in/itute giv+ 8 reasons = decl9+ to become a memb]-- 8,i ?9k m5 ( sci5ce z well z o!r m5 ne$ to le>n f ,*ri/1 & ,i ?9k ,*ri/ians ^: m9ds are sci5tific are b\nd to /udy sci5ce1 t _! view ( ! glory ( ,god may be z ext5sive z _! be+ is capable (4 ,b ,i ?9k t ! results :i* ea* man arrives at 9 8 attempts to h>monise 8 sci5ce ) 8 ,*ri/ianity ought n to be reg>d$ z hav+ any significance except to ! man himself1 & to him only = a "t1 & %\ld n receive ! /amp ( a society40 ,pr(essor ,campbell & ,mr4 ,g>nett h giv5 u ! evid5ce ( ^? :o 7 ) him 9 8 la/ days1 z to ! /r5g? ( 8 own fai?4 ,on 8 dea? b$ he said t he _h be5 occupi$ 9 try+ to ga9 tru?2 t x is b little ( tru? t man c acquire1 b x is some?+ to "k 9 :om we h believ$4 ,,*apt] ,,vii4 ,,sci5tific ,,"w--,,col\r ,,vision4 ,fifte5 ye>s only h pass$ s9ce ! dea? ( ,cl]k ,maxwell1 & x is almo/ too soon to hope to =m a correct e/imate ( ! value ( 8 "w & its relation to t ( o!rs :o h lab\r$ 9 ! same field4 ,?us ,niv51 at ! close ( 8 obitu>y notice 9 ! ,proce$+s ( ! ,royal ,society1 says3 8,x is seldom t ! faculties ( inv5tion & exposition1 ! atta*m5t to physical sci5ce & capability ( develop+ x ma!matically1 h be5 f\nd exi/+ 9 "o m9d to ! same degree4 ,x w\ld1 h[ev]1 require p[]s some:at ak9 to ,maxwell's own to describe ! m delicate features ( ! works result+ f ?is comb9ation1 e "o ( :i* is /amp$ ) ! subtle b unmi/akable impress ( g5ius40 ,& aga9 9 ! preface to ,maxwell's works1 issu$ 9 #ahij1 he wrote3 8,nor does x appe> to ! pres5t editor t ! "t has yet arriv$ :5 ! quick5+ influ5ce ( ,maxwell's m9d on mod]n sci5tific ?\ght c be duly e/imat$40 ,x is1 h[ev]1 ! object ( ! pres5t s]ies to attempt to give "s acc\nt ( ! "w ( m5 ( sci5ce ( ! la/ hundr$ ye>s1 & to %[ h[ ea* has contribut$ 8 %>e to our pres5t /ock ( k4 ,?is task1 !n1 rema9s to be done4 ,:ile attempt+ x ,i wi% to express my indebt$ness to o!rs :o h already writt5 ab\t ,maxwell's sci5tific "w1 especially to ,mr4 ,w4 ,d4 ,niv51 ^: preface to ! ,maxwell pap]s has be5 s (t5 ref]r$ to2 to ,mr4 ,g>nett1 ! au?or ( ,"p ,,ii4 ( ! 8,life ( ,maxwell10 :i* deals ) 8 contributions to sci5ce2 & to ,pr(essor ,tait1 :o 9 ,nature = ,febru>y #e?1 #ahhj1 gave an acc\nt ( ,cl]k ,maxwell's "w1 8necess>ily brief1 b suffici5t to let ev5 ! non-ma!matical read] see h[ v great 7 8 contributions to mod]n sci5ce0--an acc\nt all ! m int]e/+ because1 aga9 to quote f ,pr(essor ,tait1 8,i h be5 intimately acqua9t$ ) him s9ce we 7 s*oolboys toge!r40 ,maxwell's ma9 contributions to sci5ce may be classifi$ "u ?ree heads--8,col\r ,p]ception10 8,molecul> ,physics10 & 8,electrical ,!ories40 ,9 addition to ^! !re 7 o!r pap]s ( ! highe/ int]e/ & importance1 su* z ! essay on 8,saturn's ,r+s10 ! pap] on ! 8,equilibrium ( ,ela/ic ,solids10 & v>i\s memoirs on pure geometry & que/ions ( me*anics1 :i* w\ld1 if !y /ood alone1 h secur$ = _! au?or a di/+ui%$ position z a physici/ & ma!matician1 b :i* are n ! works by :i* 8 "n w be mo/ly rememb]$4 ,! "w on 8,col\r ,p]ception0 0 begun at an e>ly date4 ,we h se5 ,maxwell :ile /ill at ,ed9burgh int]e/$ 9 ! discussions ab\t ,hay's !ories4 ,8 fir/ publi%$ pap] on ! subject 0 a lett] to ,dr4 ,g4 ,wilson1 pr9t$ 9 ! ,transactions ( ! ,royal ,society ( ,arts = #ahee2 b he _h be5 mix+ col\rs by means ( 8 top = "s little "t previ\sly1 & ! results ( ^! exp]im5ts are giv5 9 a pap] entitl$ 8,exp]im5ts on ,col\r10 communicat$ to ! ,royal ,society ( ,ed9burgh by ,dr4 ,gregory1 & pr9t$ 9 _! ,transactions1 vol4 xxi4 ,9 ! pap] on 8,! ,!ory ( ,comp\nd ,col\rs10 pr9t$ 9 ! ,philosophical ,transactions = #ahfj1 ,maxwell gives a hi/ory ( ! !ory z x 0 kn[n to him4 ,he po9ts out fir/ ! di/9ction betwe5 ! optical prop]ties & ! *romatic prop]ties ( a beam ( light4 8,! optical prop]ties are ^? :i* h ref]5ce to its orig9 & propagation ?r\gh m$ia until x falls on ! s5sitive organ ( vision20 !y dep5d on ! p]iods & amplitudes ( ! e!r vibrations :i* compose ! beam4 8,! *romatic prop]ties are ^? :i* h ref]5ce to its p[] ( excit+ c]ta9 s5sations ( col\r p]ceiv$ ?r\gh ! organ ( vision40 ,x is possible = two beams to be optically v diff]5t & *romatically alike4 ,! conv]se is n true2 two beams :i* are optically alike are also *romatically alike4 ,! f\ndation ( ! !ory ( comp\nd col\rs 0 laid by ,newton4 ,he fir/ %ew$ t 8by ! mixture ( homog5eal light col\rs may be produc$ :i* are l to ! col\rs ( homog5eal light z to ! appe>ance ( col\r1 b n z to ! immutability ( col\r & con/itution ( light40 ,two beams :i* diff] optically may yet be alike *romatically2 x is possible by mix+ r$ & yell[ to obta9 an orange col\r *romatically simil> to ! orange ( ! spectrum1 b optically diff]5t to t orange1 = ! comp\nd orange c be analys$ by a prism into its compon5t r$ & yell[2 ! spectrum orange is incapable ( fur!r resolution4 ,newton also solves ! foll[+ problem3-- ,9 a mixture ( prim>y col\rs1 ! quantity & quality ( ea* be+ giv5 to "k ! col\r ( ! comp\nd 7,optics1 ,book #a1 ,"p #b1 ,prop4 #f71 & 8 solution is ! foll[+3--,he arranges ! sev5 col\rs ( ! spectrum r\nd ! circumf]5ce ( a circle1 ! l5g? occupi$ by ea* col\r be+ proportional to ! musical int]val to :i*1 9 ,newton's views1 ! col\r correspond$4 ,at ! c5tre ( gravity ( ea* ( ^! arcs he supposes a weight plac$ proportional to ! numb] ( rays ( ! correspond+ col\r :i* ent] into ! mixture "u consid]ation4 ,! position ( ! c5tre ( gravity ( ^! weights indicates ! nature ( ! resultant col\r4 ,a radius drawn ?r\gh ?is c5tre ( gravity po9ts out ! col\r ( ! spectrum :i* x mo/ resembles2 ! di/ance ( ! c5tre ( gravity f ! c5tre gives ! fulness ( ! col\r4 ,! c5tre itself is :ite4 ,newton gives no pro( ( ?is rule2 he m]ely says1 8,?is rule ,i conceive to be accurate en\gh = practice1 ?\gh n ma!matically accurate40 ,maxwell prov$ t ,newton's me?od ( f9d+ ! c5tre ( gravity ( ! compon5t col\rs 0 confirm$ by 8 obs]vations1 & t x involves ma!matically ! !ory ( ?ree elem5ts ( col\r2 b ! disposition ( ! col\rs on ! circle 0 only a provisional arrangem5t2 ! true relations ( ! col\rs c\ld only be det]m9$ by direct exp]im5t4 ,?omas ,"y appe>s to h be5 ! next1 aft] ,newton1 to "w at ! !ory ( col\r s5sation4 ,he made obs]vations by sp9n+ col\r$ discs mu* 9 ! same way z t :i* 0 aft]w>ds adopt$ by ,maxwell1 & he develop$ ! !ory t ?ree diff]5t prim>y s5sations may be excit$ 9 ! eye by light1 :ile ! col\r ( any beam dep5ds on ! proportions 9 :i* ^! ?ree s5sations are excit$4 ,he supposes ! ?ree prim>y s5sations to correspond to r$1 gre51 & violet4 ,a blue ray is capable ( excit+ bo? ! gre5 & ! violet2 a yell[ ray excites ! r$ & ! gre54 ,any col\r1 accord+ to ,"y's !ory1 may be mat*$ by a mixture ( ^! ?ree prim>y col\rs tak5 9 prop] proportion2 ! quality ( ! col\r dep5ds on ! proportion ( ! int5sities ( ! compon5ts2 its brightness dep5ds on ! sum ( ^! int5sities4 ,maxwell's exp]im5ts 7 und]tak5 ) ! object ( prov+ or disprov+ ! physical "p ( ,"y's !ory4 ,he does n consid] ! "q :e!r !re are ?ree di/9ct s5sations correspond+ to ! ?ree prim>y col\rs2 t is a physiological inquiry1 & "o to :i* no completely satisfactory answ] has yet be5 giv54 ,he does %[ t by a prop] mixture ( any ?ree arbitr>ily *os5 /&>d col\rs x is possible to mat* any o!r col\r2 ! words 8prop] mixture10 h[ev]1 ne$1 z w appe> %ortly1 "s developm5t4 ,we may ) advantage comp>e ! problem ) "o 9 ac\/ics4 ,:5 a comp\nd musical note consi/+ ( a pure tone & its ov]tones is s\nd$1 ! tra9$ e> c di/+ui% ! v>i\s ov]tones & analyse ! s\nd into its simple compon5ts4 ,! same s5sation _c be excit$ 9 two diff]5t ways4 ,! eye has no su* correspond+ p[]4 ,a giv5 yell[ may be a pure spectral yell[1 correspond+ to a pure tone 9 music1 or x may be a mixture ( a numb] ( o!r pure tones2 9 ei!r case x c be mat*$ by a prop] comb9ation ( ?ree /&>d col\rs--?is ,maxwell prov$4 ,x may be1 z ,"y suppos$1 t if ! ?ree /&>d col\rs be prop]ly select$ !y correspond exactly to ?ree prim>y s5sations ( ! bra94 ,maxwell's exp]im5ts d n af=d any light on ?is po9t1 :i* /ill rema9s m ?an d\btful4 ,:5 ,maxwell began 8 "w ! !ory ( col\rs 0 excit+ consid]able int]e/4 ,sir ,david ,brew/] _h rec5tly develop$ a new !ory ( col\r s5sation :i* _h =m$ ! basis ( "s discussions1 & 9 #aheb von ,helmholtz publi%$ 8 fir/ pap] on ! subject4 ,accord+ to ,brew/]1 ! ?ree primitive col\rs 7 r$1 yell[ & blue1 & he suppos$ t !y correspond$ to ?ree diff]5t k9ds ( objective light4 ,helmholtz po9t$ out t exp]im5ts up to t date _h be5 conduct$ by mix+ pigm5ts1 ) ! exception ( ^? 9 :i* ! rotat+ disc 0 us$1 & t x is necess>y to make !m on ! rays ( ! spectrum itself4 ,he !n describes a me?od ( mix+ ! light f two spectra s z to obta9 ! comb9ation ( e two ( ! simple prismatic rays 9 all degrees ( relative /r5g?4 ,f ^! exp]im5ts results1 :i* at ! "t 7 unexpect$1 b "s ( :i* mu/ h be5 kn[n to ,"y1 7 obta9$4 ,among !m x 0 %[n t a mixture ( r$ & gre5 made yell[1 :ile "o ( gre5 & violet produc$ blue4 ,9 a lat] pap] 7,philosophical ,magaz9e1 #ahed7 ,helmholtz describ$ a me?od = asc]ta9+ ! v>i\s pairs ( complem5t>y col\rs--col\rs1 t is1 :i* :5 mix$ w give :ite--:i* _h be5 %[n by ,grassman to exi/ if ,newton's !ory 7 true4 ,he also gave a provisional diagram ( ! curve =m$ by ! spectrum1 :i* ought to take ! place ( ! circle 9 ,newton's diagram2 = ?is1 h[ev]1 8 exp]im5ts did n give ! complete data4 ,su* 0 ! /ate ( ! "q :5 ,maxwell began4 ,8 fir/ col\r-box 0 made 9 #aheb4 ,o!rs 7 design$ 9 #ahee & #ahef1 & ! f9al pap] appe>$ 9 #ahfj4 ,b be=e t "t he _h e/abli%$ important results by means ( 8 rotatory discs & col\r top4 ,9 8 own description ( ?is he says3 8,! col\r$ pap] is cut into ! =m ( disc1 ea* ) a hole 9 ! c5tre & divid$ along a radius s z to admit ( sev]al ( !m be+ plac$ on ! same axis1 s t "p ( ea* is expos$4 ,by slipp+ "o disc ov] ano!r we c expose any giv5 portion ( ea* col\r4 ,^! discs are plac$ on a top or teetotum1 :i* is spun rapidly4 ,! axis ( ! top passes ?r\gh ! c5tre ( ! discs1 & ! quantity ( ea* col\r expos$ is measur$ by graduations on ! rim ( ! top1 :i* is divid$ into #ajj p>ts4 ,:5 ! top is spun suffici5tly rapidly1 ! impressions due to ea* col\r sep>ately foll[ ea* o!r 9 quick succession at ea* po9t ( ! ret9a1 & are bl5d$ toge!r2 ! /r5g? ( ! impression due to ea* col\r is1 z c be %[n exp]im5tally1 ! same z :5 ! ?ree k9ds ( light 9 ! same relative proportions ent] ! eye simultane\sly4 ,^! relative proportions are measur$ by ! areas ( ! v>i\s discs :i* are expos$4 ,two sets ( discs ( diff]5t radius are us$2 ! l>ge/ discs are put on fir/1 !n ! small]1 s t ! c5tre portion ( ! top %[s ! col\r aris+ f ! mixture ( ^? ( ! small] discs2 ! out] portion1 t ( ! l>g] discs40 ,9 exp]im5t+1 six discs ( ea* size are us$1 black1 :ite1 r$1 gre51 yell[ & blue4 ,x is f\nd by exp]im5t t a mat* c be arrang$ betwe5 any five ( ^!4 ,?us ?ree ( ! l>g] discs are plac$ on ! top--say black1 yell[ & blue--& two ( ! small] discs1 r$ & gre51 are plac$ above ^!4 ,!n x is f\nd t x is possible s to adju/ ! am\nt expos$ ( ea* disc t ! two p>ts ( ! top appe> :5 x is spun to be ( ! same t9t4 ,9 "o s]ies ( exp]im5ts ! *romatic effect ( #dfh p>ts ( black1 #bia ( yell[1 & #bda ( blue 0 f\nd to be ! same z t ( #fff ( r$ & #ccd ( gre52 ea* set ( discs has a dirty yell[ t+e4 ,n[1 9 ?is exp]im5t1 black is n a col\r2 practically no light rea*es ! eye f a dead black4 ,we h1 h[ev]1 to fill up ! circumf]5ce ( ! top 9 "s way :i* w n affect ! impression on ! ret9a aris+ f ! mixture ( ! blue & yell[2 ?is we c d by us+ ! black disc4 ,?us we h %[n t #fff p>ts ( r$ & #ccd p>ts ( gre5 produce ! same *romatic effect z #bia ( yell[ & #bda ( blue4 ,simil>ly 9 ?is mann] a mat* c be arrang$ betwe5 any f\r col\rs & black1 ! black be+ necess>y to complete ! circumf]5ce ( ! discs4 ,?us us+ ,a1 ,b1 ,c1 ,d to d5ote ! v>i\s col\rs1 a1 b1 c1 d ! am\nts ( ea* col\r tak51 we c get a s]ies ( results express$ z foll[s3 a p>ts ( ,a toge!r ) b p>ts ( ,b mat* c p>ts ( ,c toge!r ) d p>ts ( ,d2 or we may write ?is z an equation ?us3-- a ,a b ,b c ,c d ,d1 :]e ! /&s = 8comb9$ )10 & ! = 8mat*es 9 t9t40 ,we may also write ! above-- d ,d a ,a b ,b - c ,c1 or d p>ts ( ,d c be mat*$ by a prop] comb9ation ( col\rs ,a1 ,b1 ,c4 ,! sign - %[s t 9 ord] to make ! mat* we h to comb9e ! col\r ,c ) ,d2 ! comb9ation !n mat*es a mixture ( ,a & ,b4 ,9 ?is way we c =m a numb] ( equations = all possible col\rs1 & if we l to take any ?ree col\rs ,a1 ,b1 ,c z /&>ds1 we obta9 a result :i* may be writt5 g5]ally-- x ,x a ,a b ,b c ,c1 or x p>ts ( ,x c be mat*$ by a p>ts ( ,a1 comb9$ ) b p>ts ( ,b & c p>ts ( ,c4 ,if ! sign ( "o ( ! quantities a1 b1 or c is negative1 x indicates t t col\r mu/ be comb9$ ) ,x to mat* ! o!r two4 ,n[ ,maxwell 0 able to %[ t1 if ,a1 ,b1 ,c be prop]ly select$1 ne>ly e o!r col\r c be mat*$ by positive comb9ations ( ^! ?ree4 ,^! ?ree col\rs1 !n1 are prim>y col\rs1 & ne>ly e o!r col\r c be mat*$ by a comb9ation ( ! ?ree prim>y col\rs4 ,exp]im5ts1 h[ev]1 ) col\r$ discs1 su* z 7 und]tak5 by ,"y1 ,=bes & ,maxwell1 7 n capable ( giv+ satisfactory results4 ,! col\rs ( ! discs 7 n pure spectrum col\rs1 & v>i$ to "s ext5t ) ! nature ( ! incid5t light4 ,x 0 = ?is reason t ,helmholtz 9 #aheb exp]im5t$ ) ! spectrum1 & t ,maxwell ab\t ! same "t inv5t$ 8 col\r box4 ,! pr9ciple ( ! latt] 0 v simple4 ,suppose we h a slit ,s1 & "s arrangem5t = =m+ a pure spectrum on a scre54 ,let !re n[ be a slit ,r plac$ 9 ! r$ "p ( ! spectrum on ! scre54 ,:5 light falls on ! slit ,s1 only ! r$ rays c rea* ,r1 & h5ce conv]sely1 if ! :ite s\rce be plac$ at ! o!r end ( ! app>atus1 s t ,r is illum9at$ ) :ite light1 only r$ rays w rea* ,s4 ,simil>ly1 if ano!r slit be plac$ 9 ! gre5 at ,g1 & ?is be illum9at$ by :ite light1 only ! gre5 rays w rea* ,s1 :ile f a ?ird slit ,v 9 ! violet1 violet light only c arrive at ,s4 ,?us by op5+ ! ?ree slits at ,v1 ,g & ,r simultane\sly1 & look+ ?r\gh ,s1 ! ret9a receives ! impression ( ! ?ree diff]5t col\rs4 ,! am\nt ( light ( ea* col\r w dep5d on ! bread? to :i* ! correspond+ slit is op5$1 & ! relative int5sities ( ! ?ree diff]5t compon5ts c be comp>$ by comp>+ ! bread?s ( ! ?ree slits4 ,any o!r col\r :i* is all[$ by "s suitable contrivance to ent] ! eye simultane\sly c n[ be mat*$1 provid$ ! r$1 gre5 & violet are prim>y col\rs4 ,by means ( exp]im5ts ) ! col\r box ,maxwell %[$ conclusively t a mat* c\ld be obta9$ betwe5 any f\r col\rs2 ! exp]im5ts c\ld n be c>ri$ out 9 q ! simple mann] sugge/$ by ! above description ( ! pr9ciple ( ! box4 ,an acc\nt ( ! me?od w be f\nd 9 ,maxwell's own pap]4 ,x consi/$ 9 mat*+ a /&>d :ite by v>i\s comb9ations ( o!r col\rs4 ,! ma9 object ( 8 rese>*1 h[ev]1 0 to exam9e ! *romatic prop]ties ( ! diff]5t p>ts ( ! spectrum1 & to det]m9e ! =m ( ! curve :i* ought to replace ! circle 9 ,newton's diagram ( col\r4 ,maxwell adopt$ z 8 ?ree /&>d col\rs3 r$1 ( ab\t wave l5g? #f1cjb2 gre51 wave l5g? #e1bha2 & violet1 #d1efi t5? metres4 ,on ! scale ( ,maxwell's in/rum5t ^! are repres5t$ by ! numb]s #bd1 #dd & #fh4 ,let u take ?ree po9ts ,a1 ,b1 ,c at ! corn]s ( an equilat]al triangle to repres5t on a diagram ^! ?ree col\rs4 ,! position ( any o!r col\r on ! diagram w be f\nd by tak+ weights proportional to ! am\nts ( ! col\rs ,a1 ,b1 ,c requir$ to make ! mat* betwe5 ,a1 ,b1 ,c & ! giv5 col\r2 ^! weights are plac$ at ,a1 ,b1 ,c respectively2 ! position ( _! c5tre ( gravity is ! po9t requir$4 ,?us ! position ( :ite is giv5 by ! equation-- ,w #ahf 7#bd7 #cad 7#dd7 #cje 7#fh7 :i* means t weights proportional to #ahf1 #cad & #cje are to be plac$ at ,a1 ,b1 ,c respectively1 & _! c5tre ( gravity is to be f\nd4 ,! po9t s f\nd is ! position ( :ite4 ,any o!r col\r is giv5 by ! equation-- ,x a 7#bd7 b 7#dd7 c 7#fh74 ,aga91 ! position on ! diagram = all col\rs = :i* a1 b1 c are all positive lies )9 ! triangle ,a ,b ,c4 ,if "o ( ! coeffici5ts1 say c1 is negative ! same con/ruction applies1 b ! weight appli$ at ,c mu/ be treat$ z act+ 9 ! opposite direction to ^? at ,a & ,b4 ,a mixture ( ! giv5 col\r & ,c mat*es a mixture ( ,a & ,b4 ,x is cle> t ! po9t correspond+ to ,x w !n lie outside ! triangle ,a ,b ,c4 ,maxwell %[$ t1 ) 8 /&>ds1 ne>ly all col\rs c\ld be repres5t$ by po9ts inside ! triangle4 ,! col\rs he _h select$ z /&>ds 7 v close to prim>y col\rs4 ,aga91 he prov$ t any spectrum col\r betwe5 r$ & gre51 :5 comb9$ ) a v slight admixture ( violet1 c\ld be mat*$1 9 ! case ( ei!r ,mrs4 ,maxwell or himself1 by a prop] mixture ( ! r$ & gre54 ,! positions1 !re=e1 ( ! spectrum col\rs betwe5 r$ & gre5 lie j outside ! triangle ,a ,b ,c1 be+ v close to ! l9e ,a ,b1 :ile = ! col\rs betwe5 gre5 & violet ,maxwell obta9$ a curve ly+ r fur!r outside ! side ,b ,c4 ,any spectrum col\r betwe5 gre5 & violet1 toge!r ) a slight admixture ( r$1 c be mat*$ by a prop] mixture ( gre5 & violet4 ,?us ! circle ( ,newton's diagram %\ld be replac$ by a curve1 :i* co9cides v ne>ly ) ! two sides ,a ,b & ,b ,c ( ,maxwell's figure4 ,/rictly1 accord+ to 8 obs]vations1 ! curve lies j outside ^! two sides4 ,! purples ( ! spectrum lie ne>ly along ! ?ird side1 ,c ,a1 ( ! triangle1 be+ obta9$ approximately by mix+ ! violet & ! r$4 ,to f9d ! po9t on ! diagram correspond+ to ! col\r obta9$ by mix+ any two or m spectrum col\rs we mu/1 9 accordance ) ,newton's rule1 place weights at ! po9ts correspond+ to ! select$ col\rs1 & f9d ! c5tre ( gravity ( ^! weights4 ,?is1 !n1 0 ! outcome ( ,maxwell's "w on col\r4 ,x v]ifi$ ! ess5tial "p ( ,newton's con/ruction1 & obta9$ = ! fir/ "t ! true =m ( ! spectrum curve on ! diagram4 ,! =m ( ?is curve w ( c\rse dep5d on ! eye ( ! individual obs]v]4 ,?us ,maxwell & ,mrs4 ,maxwell bo? made obs]vations1 & di/9ct diff]5ces 7 f\nd 9 _! eyes4 ,x appe>s1 h[ev]1 t a l>ge majority ( p]sons h normal vision1 & t mat*es made by "o su* p]son are accept$ by mo/ o!rs z satisfactory4 ,"s p1 h[ev]1 are col\r bl9d1 & ,maxwell exam9$ a few su*4 ,9 ! case ( ^? :om he exam9$ x appe>$ z ?\gh vision 0 di*romatic1 ! r$ s5sation seem$ to be abs5t2 ne>ly all col\rs c\ld be mat*$ by comb9ations ( gre5 & violet4 ,! col\r diagram 0 r$uc$ to ! /raight l9e ,b ,c4 ,o!r =ms ( col\r bl9dness h s9ce be5 inve/igat$4 ,9 aw>d+ to ,maxwell ! ,rum=d m$al 9 #ahfj1 ,major-,g5]al ,sab9e1 vice-presid5t ( ! ,royal ,society1 aft] expla9+ ! !ory ( col\r vision & ! possible me?od ( v]ify+ x1 said3 8,pr(essor ,maxwell has subject$ ! !ory to ?is v]ification1 & !reby rais$ ! composition ( col\rs to ! rank ( a bran* ( ma!matical physics10 & he cont9ues3 8,! rese>*es = :i* ! ,rum=d m$al is aw>d$ lead to ! rem>kable result t to a v ne> degree ( approximation all ! col\rs ( ! spectrum1 & !re=e all col\rs 9 nature :i* are only mixtures ( ^!1 c be p]fectly imitat$ by mixtures ( ?ree actually atta9able col\rs1 :i* are ! r$1 gre5 & blue belong+ respectively to ?ree p>ticul> p>ts ( ! spectrum40 ,x %\ld be notic$ 9 conclud+ our rem>ks on ?is "p ( ,maxwell's "w t 8 results are purely physical4 ,!y are n inconsi/5t ) ! physiological "p ( ,"y's !ory1 viz41 t !re are ?ree prim>y s5sations ( col\r :i* c be transmitt$ to ! bra91 & t ! col\r ( any object dep5ds on ! relative proportions 9 :i* ^! s5sations are excit$1 b !y d n prove t !ory4 ,any physiological !ory :i* c be accept$ z true mu/ expla9 ,maxwell's obs]vations1 & ,"y's !ory does ?is2 b x is1 ( c\rse1 possible t o!r !ories may expla9 !m equally well1 & be m 9 accordance ) physiological obs]vations ?an ,"y's4 ,maxwell has giv5 u ! physical facts :i* h to be expla9$2 x is = ! physiologi/s to d ! re/4 ,,*apt] ,,viii4 ,,sci5tific ,,"w--,,molecul> ,,!ory4 ,maxwell 9 8 article 8,atom10 9 ! n9? edition ( ! ,encyclopdia ,britannica1 has giv5 "s acc\nt ( ,mod]n ,molecul> ,sci5ce1 & 9 p>ticul> ( ! molecul> !ory ( gases4 ,( ?is sci5ce1 ,clausius & ,maxwell are ! f\nd]s1 ?\gh to _! names x has rec5tly be5 %[n t a ?ird1 t ( ,wat]/on1 mu/ be add$4 ,9 ! pres5t *apt] x is int5d$ to give an outl9e ( ,maxwell's contributions to molecul> sci5ce1 & to expla9 ! advances due to him4 ,! doctr9e t bodies are compos$ ( small p>ticles 9 rapid motion is v anci5t4 ,democritus 0 its f\nd]1 ,lucretius--de ,r]um ,natur--expla9$ its pr9ciples4 ,! atoms d n fill space2 !re is void betwe54 8,quapropt] locus e/ intactus inane vacansque1 ,quod si non esset1 null ratione mov]i ,res poss5t2 namque (ficium quod corporis extat ,(fic]e atque ob/>e1 id 9 omni tempore adesset ,omnibus4 ,haud igitur quicquam proc$]e posset ,pr9cipium quoniam c$5di nulla d>et res40 ,accord+ to ,boscovit* an atom is an indivisible po9t1 hav+ position 9 space1 capable ( motion1 & possess+ mass4 ,x is also end[$ ) ! p[] ( ex]t+ =ce1 s t two atoms attract or repel ea* o!r ) a =ce dep5d+ on _! di/ance ap>t4 ,x has no p>ts or dim5sions3 x is a m]e geometrical po9t )\t ext5sion 9 space2 x has n ! prop]ty ( imp5etrability1 = two atoms c1 x is suppos$1 exi/ at ! same po9t4 ,9 mod]n molecul> sci5ce accord+ to ,maxwell1 8we beg9 by assum+ t bodies are made up ( p>ts ea* ( :i* is capable ( motion1 & t ^! p>ts act on ea* o!r 9 a mann] consi/5t ) ! pr9ciple ( ! cons]vation ( en]gy4 ,9 mak+ ^! assumptions we are ju/ifi$ by ! facts t bodies may be divid$ into small] p>ts1 & t all bodies ) :i* we are acqua9t$ are cons]vative sy/ems1 :i* w\ld n be ! case unless _! p>ts 7 also cons]vative sy/ems4 8,we may also assume t ^! small p>ts are 9 motion4 ,?is is ! mo/ g5]al assumption we c make1 = x includes z a p>ticul> case ! !ory t ! small p>ts are at re/4 ,! ph5om5a ( ! diffusion ( gases & liquids ?r\gh ea* o!r %[ t !re may be a motion ( ! small p>ts ( a body :i* is n p]ceptible to u4 8,we make no assumption ) respect to ! nature ( ! small p>ts--:e!r !y are all ( "o magnitude4 ,we d n ev5 assume !m to h ext5sion & figure4 ,ea* ( !m mu/ be measur$ by its mass1 & any two ( !m mu/1 l visible bodies1 h ! p[] ( act+ on "o ano!r :5 !y come ne> en\gh to d s4 ,! prop]ties ( ! body or m$ium are det]m9$ by ! configuration ( its p>ts40 ,^! small p>ticles are call$ molecules1 & a molecule 9 its physical aspect 0 def9$ by ,maxwell 9 ! foll[+ t]ms3-- 8,a molecule ( a sub/ance is a small body1 su* t if1 on ! "o h&1 a numb] ( simil> molecules 7 assembl$ toge!r1 !y w\ld =m a mass ( t sub/ance2 :ile on ! o!r h&1 if any portion ( ?is molecule 7 remov$1 x w\ld no long] be able1 along ) an assemblage ( o!r molecules simil>ly treat$1 to make up a mass ( ! orig9al sub/ance40 ,we are to look ^u a gas z an assemblage ( molecules fly+ ab\t 9 all directions4 ,! pa? ( any molecule is a /raight l9e1 except dur+ ! "t :5 x is "u ! action ( a neighb\r+ molecule2 ?is "t is usually small comp>$ ) t dur+ :i* x is free4 ,! simple/ !ory we c\ld =mulate w\ld be t ! molecules behav$ l ela/ic sph]es1 & t ! action betwe5 any two 0 a collision foll[+ ! laws :i* we "k apply to ! collision ( ela/ic bodies4 ,if ! av]age di/ance betwe5 two molecules be great comp>$ ) _! dim5sions1 ! "t dur+ :i* any molecule is 9 collision w be small comp>$ ) ! int]val betwe5 ! collisions1 & ?is is 9 accordance ) ! fundam5tal assumption j m5tion$4 ,x is n1 h[ev]1 necess>y to suppose an enc\nt] betwe5 two molecules to be a collision4 ,"o molecule may act on ano!r ) a =ce1 :i* dep5ds on ! di/ance betwe5 !m1 ( su* a "* t ! =ce is ins5sible except :5 ! molecules are extremely close toge!r4 ,x is n difficult to see h[ ! pressure ex]t$ by a gas on ! sides ( a vessel :i* conta9s x may be acc\nt$ = on ?is assumption4 ,ea* molecule z x /rikes ! side has its mom5tum rev]s$--! molecules are "h assum$ to be p]fectly ela/ic4 ,?us ea* molecule ( ! gas is cont9ually ga9+ mom5tum f ! sides ( ! vessel1 :ile x gives up to ! vessel ! mom5tum :i* x possess$ be=e ! impact4 ,! rate at :i* ?is *ange ( mom5tum proce$s across a giv5 area measures ! =ce ex]t$ on t area2 ! pressure ( ! gas is ! rate ( *ange ( mom5tum p] unit ( area ( ! surface4 ,aga91 x c be %[n t ?is pressure is proportional to ! product ( ! mass ( ea* molecule1 ! numb] ( molecules 9 a unit ( volume1 & ! squ>e ( ! velocity ( ! molecules4 ,let u consid] 9 ! fir/ in/ance ! case ( a jet ( s& or wat] ( unit cross section :i* is play+ aga9/ a surface4 ,suppose = ! pres5t t all ! molecules :i* /rike ! surface h ! same velocity4 ,!n ! numb] ( molecules :i* /rike ! surface p] second1 w be proportional to ?is velocity4 ,if ! p>ticles are mov+ quickly !y c rea* ! surface 9 "o second f a great] di/ance ?an is possible if !y be mov+ sl[ly4 ,aga91 ! numb] rea*+ ! surface w be proportional to ! numb] ( molecules p] unit ( volume4 ,h5ce1 if we call v ! velocity ( ea* p>ticle1 & ,n ! numb] ( p>ticles p] unit ( volume1 ! numb] :i* /rike ! surface 9 "o second w be ,n v2 if m be ! mass ( ea* molecule1 ! mass :i* /rikes ! surface p] second is ,n m v2 ! velocity ( ea* p>ticle ( ?is mass is v1 !re=e ! mom5tum de/roy$ p] second by ! impact is ,n m v v1 or ,n m v1 & ?is measures ! pressure4 ,h5ce 9 ?is case if p be ! pressure p ,n m v4 ,9 ! above we assume t all ! molecules 9 ! jet are mov+ ) velocity v p]p5dicul> to ! surface4 ,9 ! case ( a cr[d ( molecules fly+ ab\t 9 a clos$ space ?is is cle>ly n true4 ,! molecules may /rike ! surface 9 any direction2 !y w n all be mov+ normal to ! surface4 ,to simplify ! case1 consid] a cubical box fill$ ) gas4 ,! box has ?ree pairs ( equal faces at "r angles4 ,we may suppose "o-?ird ( ! p>ticles to be mov+ at "r angles to ea* face1 & 9 ?is case ! numb] p] unit volume :i* we h to consid] is n ,n1 b ,n4 ,h5ce ! =mula becomes p ,n m v4 ,moreov]1 if be ! d5sity ( ! gas--t is1 ! mass ( unit volume--!n ,nm is equal to 1 = m is ! mass ( ea* p>ticle1 & !re are ,n p>ticles 9 a unit ( volume4 ,h5ce1 f9ally1 p v4 ,or1 aga91 if ,v be ! volume ( unit mass ( ! gas1 !n ,v is unity1 or is equal to #a_/,v4 ,h5ce p,v v4 ,=mul equival5t to ^! appe> fir/ to h be5 obta9$ by ,h]apa? ab\t ! ye> #ahaf 7,?omson's 8,annals ( ,philosophy10 #ahaf74 ,! results only1 h[ev]1 7 /at$ 9 t ye>4 ,a pap] :i* attempt$ to e/abli% !m 0 pres5t$ to ! ,royal ,society 9 #ahbj4 ,x gave rise to v consid]able correspond5ce1 & 0 )drawn by ! au?or be=e be+ read4 ,x is pr9t$ 9 full 9 ,?omson's 8,annals ( ,philosophy0 = #ahba1 vol4 i41 pp4 #bgc1 #cdj1 #dja4 ,! argum5ts ( ! au?or are no d\bt op5 to criticism1 & are 9 _m po9ts f> f s\nd4 ,/ill1 by consid]+ ! problem ( ! impact ( a l>ge numb] ( h>d bodies1 he arriv$ at a =mula connect+ ! pressure & volume ( a giv5 mass ( gas equival5t to t j giv54 ,^! results are conta9$ 9 ,propositions viii4 & ix4 ( ,h]apa?'s pap]4 ,9 8 next /ep1 h[ev]1 ,h]apa?1 z we "k n[1 0 wrong4 ,"o ( 8 fundam5tal assumptions is t ! temp]ature ( a gas is measur$ by ! mom5tum ( ea* ( its p>ticles4 ,h5ce1 assum+ ?is1 we h ,t m v1 if ,t repres5ts ! temp]ature3 & p ,n m v 7,n_/m7 7m v74 ,or1 aga9-- p ,n,tv 7,n_/m7,t4 ,^! results are practically giv5 9 ,proposition viii41 ,corr4 7#a7 & 7#b71 & ,proposition ix4#di ,! temp]ature z ?us def9$ by ,h]apa? is an absolute temp]ature1 & he calculates ! absolute z]o ( temp]ature at :i* ! gas w\ld h no volume f ! above results4 ,! actual calculation is ( c\rse wrong1 =1 z we "k n[ by exp]im5t1 ! pressure is proportional to ! temp]ature1 & n to its squ>e1 z ,h]apa? suppos$4 ,x w be se51 h[ev]1 t ,h]apa?'s =mula gives ,boyle's law2 = if ! temp]ature is con/ant1 ! =mula is equival5t to p ,v a con/ant4 ,h]apa? some:at ext5d$ 8 "w 9 8 8,ma!matical ,physics0 publi%$ 9 #ahdg1 & appli$ 8 pr9ciples to expla9 diffusion1 ! relation betwe5 specific heat & atomic weight1 & o!r prop]ties ( bodies4 ,he /ill1 h[ev]1 reta9$ 8 errone\s supposition t temp]ature is to be measur$ by ! mom5tum ( ! individual p>ticles4 ,! next /ep 9 ! !ory 0 made by ,wat]/on4 ,8 pap] 0 read to ! ,royal ,society on ,m>* #e?1 #ahdf4 ,x 0 mo/ un=tunately committ$ to ! ,ar*ives ( ! ,society1 & 0 only dis9t]r$ by ,"l ,rayleigh 9 #ahib & pr9t$ 9 ! ,transactions = t ye>4 ,9 ! acc\nt j giv5 ( ! !ory1 x has be5 suppos$ t all ! p>ticles move ) ! same velocity4 ,?is is cle>ly n ! case 9 a gas4 ,if at />t+ all ! p>ticles _h ! same velocity1 ! collisions w\ld *ange ?is /ate ( affairs4 ,"s p>ticles w be mov+ quickly1 "s sl[ly4 ,we may1 h[ev]1 /ill apply ! !ory by splitt+ up ! p>ticles into gr\ps1 &1 suppos+ t ea* gr\p has a con/ant velocity1 ! p>ticles 9 ?is gr\p w contribute to ! pressure an am\nt--p--equal to ,n m v1 :]e v is ! velocity ( ! gr\p & ,n ! numb] ( p>ticles hav+ t velocity4 ,! :ole pressure w be f\nd by add+ t due to ! v>i\s gr\ps1 & w be giv5 z be=e by p ,n m v1 :]e v is n n[ ! actual velocity ( ! p>ticles1 b a mean velocity giv5 by ! equation ,n v ,n v ,n v 444441 :i* w produce ! same pressure z arises f ! actual impacts4 ,?is quantity v is kn[n z ! mean squ>e ( ! molecul> velocity1 & is s us$ by ,wat]/on4 ,9 a pap] 9 ! ,philosophical ,magaz9e = #aheh ,wat]/on gives an acc\nt ( 8 own pap] ( #ahdf 9 ! foll[+ t]ms3--8,mr4 ,h]apa? un=tunately assum$ heat or temp]ature to be repres5t$ by ! simple ratio ( ! velocity in/ead ( ! squ>e ( ! velocity1 be+ 9 ?is app>5tly l$ a/ray by ! def9ition ( motion g5]ally receiv$1 & ?us 0 baffl$ 9 8 attempts to reconcile 8 !ory ) obs]vation4 ,if we make ?is *ange 9 ,mr4 ,h]apa?'s def9ition ( heat or temp]ature--viz41 t x is proportional to ! vis-viva or squ>e velocity ( ! mov+ p>ticle1 n to ! mom5tum or simple ratio ( ! velocity--we c )\t mu* difficulty d$uce n only ! prim>y laws ( ela/ic fluids1 b also ! o!r physical prop]ties ( gases enum]at$ above 9 ! ?ird objection to ,newton's hypo!sis4 ,! pap] f :i* ! quotation is tak5 is on #8,! ,!ory ( ,s\nd4' ,9 ! ,ar*ives ( ! ,royal ,society = #ahde-df !re is a pap] on #8,! ,physics ( ,m$ia t consi/ ( p]fectly 8,ela/ic ,molecules 9 a ,/ate ( ,motion10' :i* conta9s ! syn!tical reason+ on :i* ! demon/ration ( ^! matt]s re/s4444 ,?is !ory does n take acc\nt ( ! size ( ! molecules4 ,x assumes t no "t is lo/ at ! impact1 & t if ! impacts produce rotatory motion1 ! vis viva ?us inve/$ be>s a con/ant ratio to ! rectil9eal vis viva1 s z n to require sep>ate consid]ation4 ,x does1 also1 n take acc\nt ( ! probable int]nal motion ( composite molecules2 yet ! results s closely accord ) obs]vation 9 e "p ( ! subject z to leave no d\bt t ,mr4 ,h]apa?'s idea ( ! physical con/itution ( gases approximates closely to ! tru?40 ,9 8 introduction to ,wat]/on's pap] 7,phil4 ,trans41 #ahib7 ,"l ,rayleigh writes3--8,impress$ ) ! above passage1 & ) ! g5]al +5uity & s\ndness ( ,wat]/on's views1 ,i took ! fir/ opportunity ( consult+ ! ,ar*ives1 & saw at once t ! memoir ju/ifi$ ! l>ge claims made = x1 & t x m>ks an imm5se advance 9 ! direction ( ! n[ g5]ally receiv$ !ory40 ,9 ! fir/ section ( ! pap] ,wat]/on's great advance consi/$ 9 ! /atem5t t ! mean squ>e ( ! k9etic en]gy ( ea* molecule measures ! temp]ature4 ,accord+ to ?is we are ?us to put 9 ! pressure equation-- m v ,t1 ! temp]ature1 & we h at once--p ,v ,n ,t4 ,n[ ?is equation expresses1 z we "k1 ! laws ( ,boyle & ,gay ,lussac4 ,! second section discusses ! prop]ties ( m$ia1 consi/+ ( two or m gases1 & arrives at ! result t 89 mix$ m$ia ! mean squ>e molecul> velocity is inv]sely proportional to ! specific weights ( ! molecules40 ,?is 0 ! great law r$iscov]$ by ,maxwell fifte5 ye>s lat]4 ,) mod]n notation x may be put ?us3--,if m1 m be ! masses ( ea* molecule ( two diff]5t sets ( molecules mix$ toge!r1 !n1 :5 a /eady /ate has be5 rea*$1 s9ce ! temp]ature is ! same ?r\gh\t1 m v is equal to m v4 ,! av]age k9etic en]gy ( ea* molecule is ! same4 ,f ?is ,avogadros' law foll[s at once--= if p1 p be ! pressures1 ,n1 ,n ! numb]s ( molecules p] unit volume-- p ,n m v1 p ,n m v4 ,h5ce1 if p1 is equal to p1 s9ce m v is equal to m v1 we mu/ h ,n equal to ,n1 or ! numb] ( molecules 9 equal volumes ( two gases at ! same pressure & temp]ature is ! same4 ,! pro( ( ?is proposition giv5 by ,wat]/on is n satisfactory4 ,on ?is po9t1 h[ev]1 we %all h m to say4 ,! ?ird section ( ! pap] deals ) adiabatic expansion1 & 9 x !re is an error 9 calculation :i* prev5t$ correct results f be+ atta9$4 ,at ! meet+ ( ! ,briti% ,association at ,ipswi*1 9 #ahea1 a pap] by ,j4 ,j4 ,wat]/on ( ,bombay1 on 8,! ,g5]al ,!ory ( ,gases10 0 read4 ,! foll[+ is an extract f ! ,proce$+s3-- ,! au?or 8conceives t ! atoms ( a gas1 be+ p]fectly ela/ic1 are 9 cont9ual motion 9 all directions1 be+ con/ra9$ )9 a limit$ space by _! collisions ) ea* o!r1 & ) ! p>ticles ( surr\nd+ bodies4 8,! vis viva ( ^! motions 9 a giv5 portion ( a gas con/itutes ! quantity ( heat conta9$ 9 x4 8,he %[s t ! result ( ?is /ate ( motion mu/ be to give ! gas an ela/icity proportional to ! mean squ>e ( ! velocity ( ! molecul> motions1 & to ! total mass ( ! atoms conta9$ 9 unity ( bulk0 7unit ( volume7--t is to say1 to ! d5sity ( ! m$ium4 8,! ela/icity 9 a giv5 gas is ! measure ( temp]ature4 ,equilibrium ( pressure & heat betwe5 two gases takes place :5 ! numb] ( atoms 9 unit ( volume is equal & ! vis viva ( ea* atom equal4 ,temp]ature1 !re=e1 9 all gases is proportional to ! mass ( "o atom multipli$ by ! mean squ>e ( ! velocity ( ! molecul> motions1 be+ measur$ f an absolute z]o #dia bel[ ! z]o ( ,fahr5heit's !rmomet]40 ,x appe>s1 !re=e1 f ^! extracts t ! discov]y ( ! laws t temp]ature is measur$ by ! mean k9etic en]gy ( a s+le molecule1 & t 9 a mixture ( gases ! mean k9etic en]gy ( ea* molecule is ! same = ea* gas1 is due to ,wat]/on4 ,!y 7 conta9$ 9 8 pap] ( #ahdf1 & publi%$ by him 9 #ahea4 ,bo? ^! pap]s1 h[ev]1 appe> to h be5 unnotic$ by all subsequ5t writ]s until #ahib4 ,mean:ile1 9 #ahdh1 ,j\le's att5tion 0 call$ by 8 exp]im5ts to ! "q1 & he saw t ,h]apa?'s result gave a means ( calculat+ ! mean velocity ( ! molecules ( a gas4 ,= accord+ to ! result giv5 above1 p v2 ?us v #c p_/1 & p & be+ kn[n1 we f9d v4 ,?us = hydrog5 at freez+-po9t & atmosph]ic pressure ,j\le obta9s = v ! value #f1jee feet p] second1 or1 r\ghly1 six times ! velocity ( s\nd 9 air4 ,clausius 0 ! next writ] ( importance on ! subject4 ,8 fir/ pap] is 9 8,pogg5dorff's ,annal510 vol4 c41 #aheg1 8,on ! ,k9d ( ,motion we call ,heat40 ,x gives an exposition ( ! !ory1 & e/abli%es ! fact t ! k9etic en]gy ( ! translatory motion ( a molecule does n repres5t ! :ole ( ! heat x conta9s4 ,if we look ^u a molecule z a small solid we mu/ consid] ! en]gy x possesses 9 consequ5ce ( its rotation ab\t its c5tre ( gravity1 z well z ! en]gy due to ! motion ( translation ( ! :ole4 ,clausius' second pap] appe>$ 9 #ahei4 ,9 x he consid]s ! av]age l5g? ( ! pa? ( a molecule dur+ ! int]val betwe5 two collisions4 ,he det]m9es ?is pa? 9 t]ms ( ! av]age di/ance betwe5 ! molecules & ! di/ance betwe5 ! c5tres ( two molecules at ! "t :5 a collision is tak+ place4 ,^! two pap]s appe> to h attract$ ,maxwell's att5tion to ! matt]1 & 8 fir/ pap]1 entitl$ 8,illu/rations ( ! ,dynamical ,!ory ( ,gases10 0 read to ! ,briti% ,association at ,ab]de5 & ,ox=d 9 #ahei & #ahfj1 & appe>$ 9 ! ,philosophical ,magaz9e1 ,janu>y & ,july1 #ahfj4 ,9 ! introduction to ?is pap] ,maxwell po9ts out1 :ile !re 0 !n no means ( measur+ ! quantities :i* occurr$ 9 ,clausius' expression = ! mean free pa?1 8! ph5om5a ( ! int]nal friction ( gases1 ! conduction ( heat ?r\gh a gas1 & ! diffusion ( "o gas ?r\gh ano!r1 seem to indicate ! possibility ( det]m9+ accurately ! mean l5g? ( pa? :i* a p>ticle describes betwe5 two collisions4 ,9 ord]1 !re=e1 to lay ! f\ndation ( su* inve/igations on /rict me*anical pr9ciples10 he cont9ues1 8,i %all demon/rate ! laws ( motion ( an indef9ite numb] ( small1 h>d & p]fectly ela/ic sph]es act+ on "o ano!r only dur+ impact40 ,maxwell !n proce$s to consid] 9 ! fir/ case ! impact ( two sph]es4 ,b a gas consi/s ( an indef9ite numb] ( molecules4 ,n[ x is impossible to deal ) ea* molecule individually1 to trace its hi/ory & foll[ its pa?4 ,9 ord]1 !re=e1 to avoid ?is difficulty ,maxwell introduc$ ! /ati/ical me?od ( deal+ ) su* problems1 & ?is introduction is ! fir/ great /ep 9 molecul> !ory ) :i* 8 "n is connect$4 ,he 0 l$ to ?is me?od by 8 inve/igation into ! !ory ( ,saturn's r+s1 :i* _h be5 complet$ 9 #ahef1 & 9 :i* he _h %[n t ! conditions ( /ability requir$ ! supposition t ! r+s are compos$ ( an indef9ite numb] ( free p>ticles revolv+ r\nd ! planet1 ) velocities dep5d+ on _! di/ances f ! c5tre4 ,^! p>ticles may ei!r be arrang$ 9 sep>ate r+s1 or _! motion may be su* t !y are cont9ually com+ into collision ) ea* o!r4 ,z an example ( ! /ati/ical me?od1 let u consid] a cr[d ( p mov+ along a /reet4 ,tak5 z a :ole ! cr[d moves /eadily =w>ds4 ,any individual 9 ! cr[d1 h[ev]1 is jo/l$ backw>ds & =w>ds & f side to side2 if a l9e 7 drawn across ! /reet we %\ld f9d p cross+ x 9 bo? directions4 ,9 a consid]able int]val m p w\ld cross x1 go+ 9 ! direction 9 :i* ! cr[d is mov+1 ?an 9 ! o!r1 & ! velocity ( ! cr[d might be e/imat$ by c\nt+ ! numb] :i* cross$ ! l9e 9 a giv5 int]val4 ,?is velocity s f\nd w\ld diff] greatly f ! velocity ( any individual1 :i* might h any value )9 limits1 & :i* is cont9ually *ang+4 ,if we knew ! velocity ( ea* individual & ! numb] ( individuals we c\ld calculate ! av]age velocity1 & ?is w\ld agree ) ! value f\nd by c\nt+ ! resultant numb] ( p :o cross ! l9e 9 a giv5 int]val4 ,aga91 ! p 9 ! cr[d w naturally fall into gr\ps accord+ to _! velocities4 ,at any mom5t !re w be a c]ta9 numb] ( p ^: velocities are all practically equal1 or1 to be m accurate1 d n diff] among !mselves by m ?an "s small quantity4 ,! numb] ( p at any mom5t 9 ea* ( ^! gr\ps w be v diff]5t4 ,! numb] 9 any gr\p1 :i* has a velocity n diff]+ greatly f ! mean velocity ( ! :ole1 w be l>ge2 comp>atively few w h ei!r a v l>ge or a v small velocity4 ,aga91 at any mom5t1 individuals are *ang+ f "o gr\p to ano!r2 a man is br\ght to a /op by "s ob/ruction1 & 8 velocity is consid]ably alt]$--he passes f "o gr\p to a diff]5t "o2 b :ile ?is is s1 if ! mean velocity rema9s con/ant1 & ! size ( ! cr[d be v great1 ! numb] ( p at any mom5t 9 a giv5 gr\p rema9s un*ang$4 ,p pass f t gr\p into o!rs1 b dur+ any int]val ! same numb] pass back aga9 into t gr\p4 ,x is cle> t if ?is condition is satisfi$ ! di/ribution is a /eady "o1 & ! cr[d w cont9ue to move on ) ! same uni=m mean velocity4 ,n[1 ,maxwell applies ^! consid]ations to a cr[d ( p]fectly ela/ic sph]es1 mov+ anyh[ 9 a clos$ space1 act+ ^u ea* o!r only :5 9 contact4 ,he %[s t !y may be divid$ into gr\ps accord+ to _! velocities1 & t1 :5 ! /eady /ate is rea*$1 ! numb] 9 ea* gr\p w rema9 ! same1 al?\gh ! individuals *ange4 ,moreov]1 x is %[n t1 if ,a & ,b repres5t any two gr\ps1 ! /ate w only be /eady :5 ! numb]s :i* pass f ! gr\p ,a to ! gr\p ,b are equal to ! numb]s :i* pass back f ! gr\p ,b to ! gr\p ,a4 ,?is condition1 comb9$ ) ! fact t ! total k9etic en]gy ( ! motion rema9s un*ang$1 enables him to calculate ! numb] ( p>ticles 9 any gr\p 9 t]ms ( ! :ole numb] ( p>ticles1 ! mean velocity1 & ! actual velocity ( ! gr\p4 ,f ?is an accurate expression c be f\nd = ! pressure ( ! gas1 & x is prov$ t ! value f\nd by o!rs1 on ! assumption t all ! p>ticles 7 mov+ ) a common velocity1 is correct4 ,previ\s to ?is pap] ( ,maxwell's x _h be5 realis$ t ! velocities c\ld n be uni=m ?r\gh\t4 ,!re _h be5 no attempt to det]m9e ! di/ribution ( velocity1 or to submit ! problem to calculation1 mak+ all[ance = ! v>iations 9 velocity4 ,maxwell's ma!matical me?ods are1 9 _! g5]ality & elegance1 f> 9 advance ( any?+ previ\sly attempt$ 9 ! subject4 ,s f> x has be5 assum$ t ! p>ticles 9 ! vessel are all alike4 ,maxwell next takes ! case ( a mixture ( two k9ds ( p>ticles1 & inquires :at relation mu/ exi/ betwe5 ! av]age velocities ( ^! diff]5t p>ticles1 9 ord] t ! /ate may be /eady4 ,n[1 x c be %[n t :5 two ela/ic sph]es imp+e ! effect ( ! impact is always su* z to r$uce ! diff]5ce betwe5 _! k9etic en]gies4 ,h5ce1 aft] a v l>ge numb] ( impacts ! k9etic en]gies ( ! two balls mu/ be ! same2 ! /eady /ate1 !n1 w be rea*$ :5 ea* ball has ! same k9etic en]gy4 ,?us if m1 m be ! masses ( ! p>ticles 9 ! two sets respectively1 v1 v _! mean velocities we mu/ h f9ally-- m v m v ,?is is ! second ( ! two great laws enunciat$ by ,wat]/on 9 #ahde & #ahea1 b :i*1 z we h se51 _h rema9$ unkn[n until #ahei1 :5 x 0 aga9 giv5 by ,maxwell4 ,n[1 :5 gases are mix$ _! temp]atures become equal4 ,h5ce we conclude1 9 ,maxwell's words1 8t ! physical condition :i* det]m9es t ! temp]ature ( two gases %all be ! same1 is t ! mean k9etic en]gy ( agitation ( ! individual molecules ( ! two gases are equal40 ,?us1 z ! result ( ,maxwell's m exact rese>*es on ! motion ( a sy/em ( sph]ical p>ticles1 we f9d t we aga9 c obta9 ! equations-- ,t mv p ,n mv ,,nt ,t_/m ,f ^! results we obta9 z be=e ! laws ( ,boyle1 ,*>les & ,avrogadro4 ,aga9 if be ! specific heat ( ! gas at con/ant volume1 ! quantity ( heat requir$ to raise a s+le molecule ( mass m "o degree w be m4 ,?us1 :5 a molecule is heat$1 ! k9etic en]gy mu/ increase by ?is am\nt4 ,b ! increase ( temp]ature1 :i* 9 ?is case is #a1 is measur$ by ! increase ( k9etic en]gy ( ! s+le molecule4 ,h5ce ! am\nt ( heat requir$ to raise ! temp]ature ( a s+le molecule ( all gases #a is ! same4 ,?us ! quantity m is ! same = all gases2 or1 9 o!r words1 ! specific heat ( a gas is inv]sely proportional to ! mass ( its individual molecules4 ,! d5sity ( a gas--s9ce ! numb] ( molecules p] unit volume at a giv5 pressure & temp]ature is ! same = all gases--is also proportional to ! mass ( ea* individual molecule4 ,?us ! specific heats ( all gases are inv]sely proportional to _! d5sities4 ,?is is ! law discov]$ exp]im5tally by ,dulong & ,petit to be approximately true = a l>ge numb] ( sub/ances4 99 99 99 99 99 ,9 ! next "p ( ! pap] ,maxwell proce$$ to det]m9e ! av]age numb] ( collisions 9 a giv5 "t1 & h5ce1 kn[+ ! velocities1 to det]m9e1 9 t]ms ( ! size ( ! p>ticles & _! numb]s1 ! mean free pa? ( a p>ticle2 ! result s f\nd diff]$ some:at f t already obta9$ by ,clausius4 ,hav+ done ?is he %[$ h[1 by means ( exp]im5ts on ! viscosity ( gases1 ! l5g? ( ! mean free pa? c\ld be det]m9$4 ,an illu/ration due to ,pr(essor ,balf\r ,/ew>t w p]haps make ?is cle>4 ,let u suppose we h two tra9s runn+ ) uni=m spe$ 9 opposite directions on p>allel l9es1 &1 fur!r1 t ! eng9es cont9ue to "w at ! same rate1 develop+ j suffici5t en]gy to ov]come ! resi/ance ( ! l9e1 etc41 & to ma9ta9 ! spe$ con/ant4 ,n[ suppose pass5g]s comm5ce to jump across f "o tra9 to ! o!r4 ,ea* man c>ries ) him 8 own mom5tum1 :i* is 9 ! opposite direction to t ( ! tra9 into :i* he jumps2 ! result is t ! mom5tum ( ea* tra9 is r$uc$ by ! process2 ! velocities ( ! two decrease2 x appe>s z ?\gh a frictional =ce 7 act+ betwe5 ! two4 ,maxwell sugge/s t a simil> process w acc\nt = ! app>5t viscosity ( gases4 ,consid] two /reams ( gas1 mov+ 9 opposite directions "o ov] ! o!r2 x is f\nd t 9 ea* case ! lay]s ( gas ne> ! sep>at+ surface move m sl[ly ?an ^? 9 ! int]ior ( ! /reams2 !re is app>5tly a frictional =ce betwe5 ! two /reams along ?is surface1 t5d+ to r$uce _! relative velocity4 ,maxwell's explanation ( ?is is t at ! common surface p>ticles f ! "o /ream ent] ! o!r1 & c>ry ) !m _! own mom5tum2 ?us ne> ?is surface ! mom5tum ( ea* /ream is r$uc$1 j z ! mom5tum ( ! tra9s is r$uc$ by ! p jump+ across4 ,int]nal friction or viscosity is due to ! diffusion ( mom5tum across ?is common surface4 ,! effect does n p5etrate f> into ! gas1 = ! p>ticles soon acquire ! velocity ( ! /ream to :i* !y h come4 ,n[1 ! rate at :i* ! mom5tum is diffus$ w measure ! frictional =ce1 & w dep5d on ! mean free pa? ( ! p>ticles4 ,if ?is is consid]able1 s t on ! av]age a p>ticle c p5etrate a consid]able di/ance into ! second gas be=e a collision takes place & its motion is *ang$1 ! viscosity w be consid]able2 if1 on ! o!r h&1 ! mean free pa? is small1 ! rev]se w be true4 ,?us x is possible to obta9 a relation betwe5 ! mean free pa? & ! coeffici5t ( viscosity1 & f ?is1 if ! coeffici5t ( viscosity be kn[n1 a value = ! mean free pa? c be f\nd4 ,maxwell1 9 ! pap] "u discussion1 0 ! fir/ to d ?is1 &1 us+ a value f\nd by ,pr(essor ,/okes = ! coeffici5t ( viscosity1 obta9$ z ! l5g? ( ! mean free pa? ( molecules ( air #a_/ddgjjj ( an in*1 :ile ! numb] ( collisions p] second exp]i5c$ by ea* molecule is f\nd to be ab\t #h1jgg1bjj1jjj4 ,moreov]1 x appe>$ f 8 !ory t ! coeffici5t ( viscosity %\ld be indep5d5t ( ! numb] ( molecules ( gas pres5t1 s t x is n alt]$ by v>y+ ! d5sity4 ,?is result ,maxwell *>act]ises z />tl+1 & he in/itut$ an elaborate s]ies ( exp]im5ts a few ye>s lat] ) a view ( te/+ x4 ,! reason = ?is result w appe> if we rememb] t1 :5 ! d5sity is decreas$1 ! mean free pa? is increas$2 relatively1 !n1 to ! total numb] ( molecules pres5t1 ! numb] :i* cross ! surface 9 a giv5 "t is increas$4 ,& x appe>s f ,maxwell's result t ?is relative increase is su* t ! total numb] cross+ rema9s un*ang$4 ,h5ce ! mom5tum convey$ across ea* unit area p] second rema9s ! same1 9 spite ( ! decrease 9 d5sity4 ,ano!r consequ5ce ( ! same inve/igation is t ! coeffici5t ( viscosity is proportional to ! mean velocity ( ! molecules4 ,s9ce ! absolute temp]ature is proportional to ! squ>e ( ! velocity1 x foll[s t ! coeffici5t ( viscosity is proportional to ! squ>e root ( ! absolute temp]ature4 ,! second "p ( ! pap] deals ) ! process ( diffusion ( two or m k9ds ( mov+ p>ticles among "o ano!r4 ,if two diff]5t gases are plac$ 9 two vessels sep>at$ by a por\s diaphragm su* z a piece ( unglaz$ e>!nw>e1 or connect$ by means ( a n>r[ tube1 ,graham _h %ewn t1 aft] suffici5t "t has elaps$1 ! two are mix$ toge!r4 ,! same process takes place :5 two gases ( diff]5t d5sity are plac$ toge!r 9 ! same vessel4 ,at fir/ ! d5s] gas may be at ! bottom1 ! less d5se above1 b aft] a "t ! two are f\nd to be uni=mly di/ribut$ ?r\gh\t4 ,maxwell attempt$ to calculate f 8 !ory ! rate at :i* ! diffusion takes place 9 ^! cases4 ,! conditions ( mo/ ( ,graham's exp]im5ts 7 too complicat$ to admit ( direct comp>ison ) ! !ory1 f :i* x appe>$ t !re is a relation betwe5 ! mean free pa? & ! rate ( diffusion4 ,"o exp]im5t1 h[ev]1 0 f\nd1 ! conditions ( :i* c\ld be made ! subject ( calculation1 & f x ,maxwell obta9$ z ! value ( ! mean free pa? 9 air #a_/chijjj ( an in*4 ,! numb] 0 close en\gh to t f\nd f ! viscosity to af=d "s confirmation ( 8 !ory4 ,h[ev]1 a few ye>s lat] ,clausius criticis$ ! details ( ?is "p ( ! pap]1 & ,maxwell1 9 8 memoir ( #ahff1 admits ! calculation to h be5 errone\s4 ,! ma9 pr9ciples rema9$ unaffect$1 ! molecules pass f "o gas to ! o!r1 & ?is con/itutes diffusion4 ,n[1 suppose we h two sets ( p>ticles 9 contact ( su* a nature t ! mean k9etic en]gy ( ! "o set is diff]5t f t ( ! o!r2 ! temp]atures ( ! two w !n be diff]5t4 ,^! two sets w diffuse into ea* o!r1 & ! diffus+ p>ticles w c>ry ) !m _! k9etic en]gy1 :i* w gradually pass f ^? :i* h ! great] en]gy to ^? :i* h ! less1 until ! av]age k9etic en]gy is equalis$ ?r\gh\t4 ,b ! k9etic en]gy ( translation is ! heat ( ! p>ticles4 ,?is diffusion ( k9etic en]gy is a diffusion ( heat by conduction1 & we h "h ! me*anical !ory ( ! conduction ( heat 9 a gas4 ,maxwell obta9$ an expression1 :i*1 h[ev]1 he aft]w>ds modifi$1 = ! conductivity ( a gas 9 t]ms ( ! mean free pa?4 ,x foll[$ f ?is t ! conductivity ( air 0 only ab\t #a_/gjjj ( t ( copp]4 ,?us ! diffusion ( gases1 ! viscosity ( gases1 & ! conduction ( heat 9 gases1 are all connect$ ) ! diffusion ( ! p>ticles c>ry+ ) !m _! mom5ta & _! en]gy2 :ile values ( ! mean free pa? c be obta9$ f obs]vations on any "o ( ^! prop]ties4 ,9 ! ?ird "p ( 8 pap] ,maxwell consid]s ! consequ5ces ( suppos+ ! p>ticles n to be sph]ical4 ,9 ?is case ! impacts w\ld t5d to set up a motion ( rotation 9 ! p>ticles4 ,! direction ( ! =ce act+ on any p>ticle at impact w\ld n necess>ily pass ?r\gh its c5tre2 ?us by impact ! velocity ( its c5tre w\ld be *ang$1 & 9 addition ! p>ticles w\ld be made to sp94 ,"s "p1 !re=e1 ( ! en]gy ( ! p>ticles w appe> 9 ! =m ( ! translational en]gy ( _! c5tres1 :ile ! re/ w take ! =m ( rotational en]gy ( ea* p>ticle ab\t its c5tre4 ,x foll[s f ,maxwell's "w t = ea* p>ticle ! av]age value ( ^! two portions ( en]gy w\ld be equal4 ,! total en]gy w be half translational & half rotational4 ,?is !orem1 9 a m g5]al =m :i* 0 aft]w>ds giv5 to x1 has l$ to mu* discussion1 & w be aga9 consid]$ lat]4 ,= ! pres5t we w assume x to be true4 ,clausius _h already call$ att5tion to ! fact t "s ( ! en]gy mu/ be rotational unless ! molecules be smoo? sph]es1 & _h giv5 "s reasons = suppos+ t ! ratio ( ! :ole en]gy to ! en]gy ( translation is 9 a /eady /ate a con/ant4 ,maxwell %[s t = rigid bodies ?is con/ant is #b4 ,let u d5ote x = ! pres5t by ! symbol 4 ,?us1 if ! translational en]gy ( a molecule is m v1 its :ole en]gy is m v4 ,! temp]ature is /ill measur$ by ! translational en]gy1 or m v2 ! heat dep5ds on ! :ole en]gy4 ,h5ce if ,h repres5t ! am\nt ( heat--measur$ z en]gy--conta9$ by a s+le molecule1 & ,t its temp]ature1 we h-- ,h ,t ,f ?is x c be %ewn#ej t if repres5t ! ratio ( ! specific heat ( a gas at con/ant pressure to ! specific heat at con/ant volume1 !n-- #a_/7-a7 ,= air & "s o!r gases ! value ( has be5 %[n to be #adjh4 ,f ?is x foll[s t #afcd4 ,n[1 ,maxwell's !ory requir$ t = smoo? h>d p>ticles1 approximately sph]ical 9 %ape1 %\ld be #b1 & h5ce he concludes 8we h %[n t a sy/em ( su* p>ticles c\ld n possibly satisfy ! kn[n relation betwe5 ! two specific heats ( all gases40 ,s9ce ?is /atem5t 0 made _m m exp]im5ts on ! value ( h be5 und]tak52 x is n equal to #adjh = all gases4 ,h5ce ! value ( is diff]5t = v>i\s gases4 ,x is ( "s importance to notice t ! value ( j f\nd = air is v approximately #aff or #e_/c4 ,= m]cury vap\r ! value ( has be5 %[n by ,kundt to be #acc or #a1 & h5ce is equal to #a4 ,?us all ! en]gy ( a p>ticle ( m]cury vap\r is translational1 & its behavi\r 9 ?is respect is consi/5t ) ! assumption t a p>ticle ( m]cury vap\r is a smoo? sph]e4 ,! two results ( ?is !ory :i* seem$ to l5d !mselves mo/ readily to exp]im5tal v]ification 7 7#a7 t ! viscosity ( a gas is indep5d5t ( its d5sity1 & 7#b7 t x is proportional to ! squ>e root ( ! absolute temp]ature4 ,! next piece ( "w connect$ ) ! !ory 0 an attempt to te/ ^! consequ5ces1 & a description ( ! exp]im5ts 0 publi%$ 9 ! 8,philosophical ,transactions0 = #ahfe1 9 a pap] on ! 8,viscosity or ,int]nal ,friction ( ,air & o!r ,gases10 & =ms ! ,bak]ian lecture = t ye>4 ,! fir/ result 0 completely prov$4 ,x is %ewn t ! value ( ! coeffici5t#ea ( viscosity 8is ! same = air at #je in* & at #cj in*es pressure1 provid$ t ! temp]ature rema9s ! same40 ,x 0 cle> also t ! viscosity dep5d$ on ! temp]ature1 & ! results ( ! exp]im5ts seem$ to %[ t x 0 ne>ly proportional to ! absolute temp]ature4 ,?us = two temp]atures1 #ahe ,fah4 & #ea ,fah41 ! ratio ( ! two coeffici5ts f\nd 0 #abfbd2 ! ratio ( ! two temp]atures1 ea* measur$ f absolute z]o1 is #abfje4 ,?is result1 !n1 does n agree ) ! hypo!sis t a gas consi/s ( sph]ical molecules act+ only on ea* o!r by a k9d ( impact1 =1 if ?is 7 s1 ! coeffici5t w\ld1 z we h se51 dep5d on ! squ>e root ( ! absolute temp]ature4 ,b ,maxwell's result1 connect+ viscosity ) ! fir/ p[] ( ! absolute temp]ature1 has n be5 confirm$ by o!r inve/igators4 ,accord+ to x we %\ld h z ! relation betwe5 1 ! coeffici5t ( viscosity at t & 1 t at z]o ! equation-- 7#a 4#jjcfe t74 ,! mo/ rec5t results ( ,pr(essor ,holman 7,philosophical ,magaz9e1 ,vol4 xxi41 p4 #bab7 give-- 7#a 4#jjbge t - 4#jjjjjjcd t74 ,& results simil> to ?is are giv5 by ,o4 ,e4 ,mey]1 ,puluj1 & ,ob]mey]4 ,maxwell's coeffici5t #jjcfe is too l>ge1 b #jjahb1 ! coeffici5t obta9$ by suppos+ ! viscosity proportional to ! squ>e root ( ! temp]ature1 w\ld be too small4 ,x /ill rema9s true1 !re=e1 t ! laws ( ! viscosity ( gases _c be expla9$ by ! hypo!sis ( ! impact ( h>d sph]es2 b "s d$uctions drawn by ,maxwell 9 8 next pap] f 8 suppos$ law ( proportionality to ! fir/ p[] ( ! absolute temp]ature require modification4 ,x 0 cle> f 8 exp]im5ts j describ$ t ! simple hypo!sis ( ! impact ( ela/ic bodies w\ld n acc\nt = all ! ph5om5a obs]v$4 ,accord+ly1 9 #ahff1 ,maxwell took up ! problem 9 a m g5]al =m 9 8 pap] on ! 8,dynamical ,!ory ( ,gases10 ,phil4 ,trans41 #ahff4 ,9 x he consid]$ ! molecules ( ! gas n z ela/ic sph]es ( def9ite radius1 b z small bodies1 or gr\ps ( small] molecules1 repell+ "o ano!r ) a =ce ^: direction always passes v ne>ly ?r\gh ! c5tre ( gravity ( ! molecules1 & ^: magnitude is repres5t$ v ne>ly by "s function ( ! di/ance ( ! c5tres ( gravity4 8,i h made10 he cont9ues1 8?is modification ( ! !ory 9 consequ5ce ( ! results ( my exp]im5ts on ! viscosity ( air at diff]5t temp]atures1 & ,i h d$uc$ f ^! exp]im5ts t ! repulsion is inv]sely z ! fif? p[] ( ! di/ance40 ,s9ce m rec5t obs]vation has %[n t ! num]ical results ( ,maxwell's "w connect+ viscosity & temp]ature are errone\s1 ?is la/ d$uction does n hold2 ! inv]se fif? p[] law ( =ce w n give ! correct relation betwe5 viscosity & temp]ature4 ,maxwell himself at a lat] date1 8,on ! ,/resses 9 ,r>efi$ ,gases10 ,phil4 ,trans41 #ahgi1 realis$ ?is2 b ev5 9 ?is la/ pap] he adh]$ to ! fif? p[] law because x leads to an important simplification 9 ! equations to be dealt )4 ,! pap] ( #ahff is *iefly important because x conta9s = ! fir/ "t ! application ( g5]al dynamical me?ods to molecul> problems4 ,! law ( ! di/ribution ( velocities among ! molecules is aga9 inve/igat$1 & a result practically id5tical ) t f\nd = ! ela/ic sph]es is arriv$ at4 ,9 obta9+ ?is conclusion1 h[ev]1 x is assum$ t ! di/ribution ( velocities is uni=m 9 all directions ab\t any po9t1 :atev] actions may be tak+ place 9 ! gas4 ,if1 = example1 ! temp]ature is diff]5t at diff]5t po9ts1 !n1 = a giv5 velocity1 all directions are n equally probable4 ,maxwell's expression1 !re=e1 = ! numb] ( molecules :i* at any mom5t h a giv5 velocity only applies to ! p]man5t /ate 9 :i* ! di/ribution ( temp]ature is uni=m4 ,:5 deal+1 = example1 ) ! conduction ( heat1 a modification ( ! expression is necess>y4 ,?is 0 po9t$ out by ,boltzmann4#eb ,9 ! pap] ( #ahff1 ,maxwell applies 8 g5]alis$ results to ! f9al di/ribution ( two gases "u ! action ( gravity1 ! equilibrium ( temp]ature betwe5 two gases1 & ! di/ribution ( temp]ature 9 a v]tical column4 ,^! results are1 z he /ates1 indep5d5t ( ! law ( =ce betwe5 ! molecules4 ,! dynamical causes ( diffusion viscosity & conduction ( heat are dealt )1 & ^! involve ! law ( =ce4 ,x foll[s also f ! inve/igation t1 on ! hypo!ses assum$ z its basis1 if two k9ds ( gases be mix$1 ! diff]5ce betwe5 ! av]age k9etic en]gies ( translation ( ! gases ( ea* k9d dim9i%es rapidly 9 consequ5ce ( ! action betwe5 ! two4 ,! av]age k9etic en]gy ( translation1 !re=e1 t5ds to become ! same = ea* k9d ( gas1 & z be=e1 x is ?is av]age en]gy ( translation :i* measures ! temp]ature4 ,a molecule 9 ! !ory is a portion ( a gas :i* moves ab\t z a s+le body4 ,x may be a m]e po9t1 a c5tre ( =ce hav+ in]tia1 capable ( do+ "w :ile los+ velocity4 ,!re may be also 9 ea* molecule sy/ems ( sev]al su* c5tres ( =ce b\nd toge!r by _! mutual actions4 ,aga91 a molecule may be a small solid body ( det]m9ate =m2 b 9 ?is case we mu/1 z ,maxwell po9ts out1 introduce a new set ( =ces b9d+ toge!r ! p>ts ( ea* molecule3 we mu/ h a molecul> !ory ( ! second ord]4 ,9 any case1 ! mo/ g5]al supposition made is t a molecule consi/s ( a s]ies ( p>ts :i* /ick toge!r1 b are capable ( relative motion among ea* o!r4 ,9 ?is case ! k9etic en]gy ( ! molecule consi/s ( ! en]gy ( its c5tre ( gravity1 toge!r ) ! en]gy ( its compon5t p>ts1 relative to its c5tre ( gravity4#ec ,n[ ,clausius _h1 z we h se51 giv5 reasons = believ+ t ! ratio ( ! :ole en]gy ( a molecule to ! en]gy ( translation ( its c5tre ( gravity t5ds to become con/ant4 ,we h already us$ to d5ote ?is con/ant4 ,?us1 :ile ! temp]ature is measur$ by ! av]age k9etic en]gy ( translation ( ! c5tre ( gravity ( ea* molecule1 ! heat conta9$ 9 a molecule is its :ole en]gy1 & is times ?is quantity4 ,?us ! conclusions z to specific heat1 etc41 already giv5 on page #acj1 apply 9 ?is case1 & 9 p>ticul> we h ! result t if be ! ratio ( ! specific heat at con/ant pressure to t at con/ant volume1 !n-- #a_/7-a7 ,maxwell's !orem ( ! di/ribution ( k9etic en]gy among a sy/em ( molecules appli$1 z he gave x 9 #ahff1 to ! k9etic en]gy ( translation ( ! c5tre ( gravity ( ea* molecule4 ,two ye>s lat] ,dr4 ,boltzmann1 9 ! pap] we h already ref]r$ to1 ext5d$ x 7"u c]ta9 limitations7 to ! p>ts ( :i* a molecule is compos$4 ,accord+ to ,maxwell ! av]age k9etic en]gy ( ! c5tre ( gravity ( ea* molecule t5ds to become ! same4 ,accord+ to ,boltzmann ! av]age k9etic en]gy ( ea* "p ( ! molecule t5ds to become ! same4 ,maxwell1 9 ! la/ pap] he wrote on ! subject 78,on ,boltzmann's ,!orem on ! ,av]age ,di/ribution ( ,en]gy 9 a ,sy/em ( ,mat]ial ,po9ts10 ,camb4 ,phil4 ,trans41 ,,xii471 took up ?is problem4 ,watson _h giv5 a pro( ( x 9 #ahgf diff]+ f ,boltzmann's1 b /ill limit$ by ! /ipulation t ! "t1 dur+ :i* a p>ticle is enc\nt]+ o!r p>ticles1 is v small comp>$ ) ! "t dur+ :i* !re is no s5sible action betwe5 x & o!r p>ticles1 & also t ! "t dur+ :i* a p>ticle is simultane\sly )9 ! di/ance ( m ?an "o o!r p>ticle may be neglect$4 ,maxwell claims t 8 pro( is free f any su* limitation4 ,! mat]ial po9ts may act on ea* o!r at all di/ances1 & accord+ to any law :i* is consi/5t ) ! cons]vation ( en]gy2 !y may also be act$ on by =ces ext]nal to ! sy/em1 provid$ ^! are consi/5t ) t law4 ,! only assumption :i* is necess>y = ! direct pro( is t ! sy/em1 if left to itself 9 its actual /ate ( motion1 w soon] or lat] pass ?r\gh e phase :i* is consi/5t ) ! cons]vation ( en]gy4 ,9 ?is pap] ,maxwell f9ds 9 a v g5]al mann] an expression = ! numb] ( molecules :i* at any "t h a giv5 velocity1 & ?is1 :5 simplifi$ by ! assumptions ( ! =m] pap]s1 r$uces to ! =m already f\nd4 ,he also %[s t ! av]age k9etic en]gy correspond+ to any "o ( ! v>iables :i* def9e 8 sy/em is ! same = e "o ( ! v>iables ( 8 sy/em4 ,?us1 accord+ to ?is !orem1 if ea* molecule be a s+le small solid body1 six v>iables w be requir$ to det]m9e ! position ( ea*1 ?ree v>iables w give u ! position ( ! c5tre ( gravity ( ! molecule1 :ile ?ree o!rs w det]m9e ! position ( ! body relative to its c5tre ( gravity4 ,if ! six v>iables be prop]ly *os51 ! k9etic en]gy c be express$ z a sum ( six squ>es1 "o squ>e correspond+ to ea* v>iable4 ,accord+ to ! !orem ! "p ( ! k9etic en]gy dep5d+ on ea* squ>e is ! same4 ,?us1 ! :ole en]gy is six times z great z t :i* arises f any "o ( ! v>iables4 ,! k9etic en]gy ( translation is ?ree times z great z t aris+ f ea* v>iable1 = x involves ! ?ree v>iables :i* det]m9e ! position ( ! c5tre ( gravity4 ,h5ce1 if we d5ote by ,k ! k9etic en]gy due to "o v>iable1 ! :ole en]gy is #f ,k1 & ! translational en]gy is #c ,k2 ?us1 = ?is case-- #f,k_/#c,k #b ,or1 aga91 if we suppose t ! molecule is su* t m v>iables are requir$ to det]m9e its position relatively to its c5tre ( gravity1 s9ce #c are ne$$ to fix ! c5tre ( gravity1 ! total numb] ( v>iables def9+ ! position ( ! molecule is m #c1 & x is said to h m #c degrees ( fre$om4 ,h5ce1 9 ?is case1 its total en]gy is 7m #c7 ,k & its en]gy ( translation is #c ,k1 ?us we f9d-- 7m #c7_/c ,h5ce #a #b_/7m #c7 #a #b_/n if n be ! numb] ( degrees ( fre$om ( ! molecule4 ,?us1 if ?is ,boltzmann-,maxwell !orem be true1 ! specific heat ( a gas w dep5d solely on ! numb] ( degrees ( fre$om ( ea* ( its molecules4 ,= h>d rigid bodies we %\ld h n equal to #f1 & h5ce #accc4 ,n[ ! fact t ?is is n ! value ( = any ( ! kn[n gases is a fundam5tal difficulty 9 ! way ( accept+ ! complete !ory4 ,boltzmann has call$ att5tion to ! fact t if n be equal to five1 !n has ! value #adj4 ,& ?is agrees fairly ) ! value f\nd by exp]im5t = air1 oxyg51 nitrog51 & v>i\s o!r gases4 ,we w1 h[ev]1 return to ?is po9t %ortly4 ,!re is1 p]haps1 no result 9 ! doma9 ( physical sci5ce 9 rec5t ye>s :i* has be5 m discuss$ ?an ! two fundam5tal !orems ( ! molecul> !ory :i* we owe to ,maxwell & to ,boltzmann4 ,! two results 9 "q are 7#a7 ! expression = ! numb] ( molecules :i* at any mom5t w h a giv5 velocity1 & 7#b7 ! proposition t ! k9etic en]gy is ultimately equally divid$ among all ! v>iables :i* det]m9e ! sy/em4 ,) reg>d to 7#a7 ,maxwell %[$ t 8 error law 0 "o possible condition ( p]man5ce4 ,if at any mom5t ! velocities are di/ribut$ accord+ to ! error law1 t di/ribution w be a p]man5t "o4 ,he did n prove t su* a di/ribution is ! only "o :i* c satisfy all ! conditions ( ! problem4 ,! pro( t ?is law is a necess>y1 z well z a suffici5t1 condition ( p]man5ce 0 fir/ giv5 by ,boltzmann1 = a s+le monatomic gas 9 #ahgb1 = a mixture ( su* gases 9 #ahhf1 & = a polyatomic gas 9 #ahhg4 ,o!r pro(s h be5 giv5 s9ce by ,watson & ,burbury4 ,x w\ld be q beyond ! limits ( ?is book to g into ! "q ( ! complet5ess or suffici5cy ( ! pro(s4 ,! discussion ( ! "q is /ill 9 progress4 ,! ,briti% ,association ,report = #ahid conta9s an important contribution to ! "q1 9 ! %ape ( a report by ,mr4 ,g4 ,h4 ,bryan1 & ! discussion he />t$ at ,ox=d by read+ ?is report has be5 cont9u$ 9 ! pages ( ,nature & else:]e s9ce t "t4 ,mr4 ,bryan %[s 9 ! fir/ place :at may be ! nature ( ! sy/ems ( molecules to :i* ! results w apply1 & discusses v>i\s po9ts ( difficulty 9 ! pro(4 ,! !orem 9 "q1 f :i* ! result 7#a7 foll[s z a simple d$uction1 has be5 ?us /at$ by ,dr4 ,l>mor4#ed 8,!re exi/s a positive function belong+ to a gr\p ( molecules :i*1 z !y settle !mselves into a /eady /ate--on ! av]age d]iv$ f a great numb] ( configurations--ma9ta9s a /eady d[nw>d tr5d4 ,! ,maxwell-,boltzmann /eady /ate is ! "o 9 :i* ?is function has f9ally atta9$ its m9imum value1 & is ?us a unique /eady /ate1 x /ill be+ borne 9 m9d t ?is is only a proposition ( av]ages d]iv$ f a great numb] ( in/ances 9 :i* no?+ is cons]v$ 9 enc\nt]s1 except ! en]gy1 & t exceptional circum/ances may exi/1 comp>atively v few 9 numb]1 9 :i* ! tr5d is1 at any rate1 tempor>ily ! o!r way40 ,?is !orem1 :5 appli$ to cases ( motion1 su* z t ( a gas at con/ant temp]ature enclos$ 9 a rigid envelope imp]meable to heat1 appe>s to be prov$4 ,= su* a case1 !re=e1 ! ,maxwell-,boltzmann law is ! only "o possible4 ,b :e!r ?is be s or n1 ! law fir/ introduc$ by ,maxwell is "o ( ^? possible1 & ! advance 9 molecul> sci5ce due to its introduction is enorm\s4 ,we come n[ to ! second result1 ! equal p>tition ( ! en]gy among all ! degrees ( fre$om ( ea* molecule4 ,"l ,kelv9 has po9t$ out a flaw 9 ,maxwell's pro(1 b ,boltzmann %[$ 7,philosophical ,magaz9e1 ,m>*1 #ahic7 h[ ?is flaw c easily be correct$1 & x may be said t 9 all cases 9 :i* ! ,boltzmann-,maxwell law ( ! di/ribution ( velocities holds1 ,maxwell's law ( ! equal p>tition ( en]gy holds also4 ,?ree cases are consid]$ by ,mr4 ,bryan1 9 :i* ! law ( di/ribution fails = rigid molecules3 ! fir/ is :5 ! molecules h all1 9 addition to _! velocities ( agitation1 a common velocity ( translation 9 a fix$ direction2 ! second is :5 ! gas has a motion ( uni=m rotation ab\t a fix$ axis2 :ile ! ?ird is :5 ea* molecule has an axis ( symmetry4 ,9 ?is la/ case ! =ces act+ dur+ a collision necess>ily pass ?r\gh ! axis ( symmetry1 ! angul> velocity1 !re=e1 ( any molecule ab\t ?is axis rema9s con/ant1 ! numb] ( molecules hav+ a giv5 angul> velocity w rema9 ! same ?r\gh\t ! motion1 & ! "p ( ! k9etic en]gy :i* dep5ds on ?is compon5t ( ! motion w rema9 fix$1 & w n come into consid]ation :5 deal+ ) ! equal p>tition ( ! en]gy among ! v>i\s degrees ( fre$om4 ,su* a molecule has five1 & n six1 degrees ( fre$om2 ?ree quantities are ne$$ to det]m9e ! position ( its c5tre ( gravity1 & two to fix ! position ( ! axis ( symmetry4 ,9 ?is case1 !n1 z ,boltzmann po9ts out1 9 ! expression = ! ratio ( ! specific heats1 we mu/ h n equal to #e1 & h5ce #a #b_/n #a #b_/e #ad agree+ fairly ) ! value f\nd = air & v>i\s o!r p]man5t gases4 ,= cases1 !n1 9 :i* we consid] ea* atom z a s+le rigid body1 ! ,boltzmann-,maxwell !orem appe>s to give a unique solution1 & ! ,maxwell law ( ! di/ribution ( ! en]gy to be 9 fair accordance ) ! results ( obs]vation4#ee ,if we c nev] g fur!r--& x mu/ be admitt$ t ! difficulties 9 ! way ( fur!r advance are enorm\s--x may1 ,i ?9k1 be claim$ = ,maxwell t ! progress already made is greatly due to him4 ,bo? ^! laws1 = ! case ( ela/ic sph]es1 are conta9$ 9 8 fir/ pap] ( #ahfj2 & :ile x is to ! g5ius ( ,boltzmann t we owe _! e>lie/ g5]alisation1 & 9 p>ticul> ! pro( ( ! uniqu5ess ( ! solution "u prop] re/rictions1 ,maxwell's la/ pap] contribut$ 9 no small degree to ! security ( ! position4 ,n m]ely ! f\ndations1 b mu* ( ! sup]/ructure ( molecul> sci5ce is 8 "w4 ,! difficulties 9 ! way ( advance are1 z we h said1 enorm\s4 ,boltzmann1 9 "o ( 8 pap]s1 has consid]$ ! prop]ties ( a complex molecule ( a gas1 consi/+ maybe ( a numb] ( atoms & possibly ( e!r atoms b\nd ) !m1 & he concludes t su* a molecule w behave 9 its progressive motion1 & 9 its collisions ) o!r molecules1 ne>ly l a rigid body4 ,b to quote f ,mr4 ,bryan3 8,! case ( a polyatomic molecule1 ^: atoms are capable ( vibrat+ relative to "o ano!r1 af=ds an int]e/+ field = inve/igation & speculation4 ,is ! ,boltzmann di/ribution /ill unique1 or d o!r p]man5t di/ributions exi/ 9 :i* ! k9etic en]gy is unequally divid$80 ,aga91 ! spectroscope reveals to u vibrations ( ! e!r1 :i* are connect$ 9 "s way ) ! vibrations ( ! molecules ( gas1 ^: spectrum we are obs]v+4 ,x seems cle> t ! law ( equal p>tition does n apply to ^!1 & yet1 if we are to suppose t ! e!r vibrations are due to actual vibrations ( ! atoms :i* con/itute a molecule1 :y does x n apply8 ,:]e does ! condition come 9 :i* leads to failure 9 ! pro(8 ,or1 aga91 is x1 z has be5 sugge/$1 ! fact t ! complex spectrum ( a gas repres5ts ! t]ms ( a ,f\ri] ,s]ies1 into :i* "s elaborate vibration ( ! atoms is resolv$ by ! e!r8 or is ! spectrum due simply to electro-magnetic vibrations on ! surface ( ! molecules--vibrations ^: p]iod is det]m9$ *iefly by ! size & %ape ( ! molecule1 b 9 :i* ! atoms ( :i* x is compos$ take "p8 ,!re are grave difficulties 9 ! way ( ei!r ( ^! explanations1 b we mu/ n let our dread ( ! task :i* rema9s to be done bl9d our eyes to ! greatness ( ,maxwell's "w4 ,"o o!r important pap]1 & a numb] ( %ort] articles1 rema9 to be m5tion$4 ,! ,boltzmann-,maxwell law applies only to cases 9 :i* ! temp]ature is uni=m ?r\gh\t4 ,9 a pap] publi%$ 9 ! ,philosophical ,transactions = #ahgi1 on 8,/resses 9 ,r>efi$ ,gases ,aris+ f ,inequalities ( ,temp]ature10 ,maxwell deals1 among o!r matt]s1 ) ! !ory ( ! radiomet]4 ,he %[s t ! obs]v$ motions w n take place unless gas1 9 contact ) a solid1 c slide along ! surface ( ! solid ) a f9ite velocity betwe5 places :]e ! temp]ature is diff]5t2 & 9 an app5dix he proves t1 on c]ta9 assumptions reg>d+ ! nature ( ! contact ( ! solid & ! gas1 !re w be1 ev5 :5 ! pressure is con/ant1 a fl[ ( gas along ! surface f ! cold] to ! hott] p>ts4 ,among 8 less important pap]s be>+ on molecul> !ory mu/ be m5tion$ a lecture on 8,molecules0 to ! ,briti% ,association at its ,brad=d meet+2 8,sci5tific ,pap]s ( ,cl]k ,maxwell10 vol4 ii41 p4 #cfa2 & ano!r on 8,! ,molecul> ,con/itution ( ,bodies10 ,sci5tific ,pap]s1 vol4 ii41 p4 #dah4 ,9 ?is latt]1 & also 9 a review 9 ,nature ( ,van d] ,waals' book on 8,! ,cont9uity ( ! ,gase\s & ,liquid ,/ates10#ef he expla9s & discusses ,clausius' virial equation1 by means ( :i* ! v>iations ( ! p]man5t gases f ,boyle's law are expla9$4 ,! lecture gives a cle> acc\nt1 9 ,maxwell's own inimitable /yle1 ( ! advances made 9 ! k9etic !ory up to ! date at :i* x 0 deliv]$1 & puts cle>ly ! difficulties x has to meet4 ,maxwell ?\ght t ^? aris+ f ! kn[n values ( ! ratio ( ! specific heats 7 ! mo/ s]i\s4 ,9 ! articles1 8,atomic ,con/itution ( ,bodies0 & 8,diffusion10 9 ! n9? edition ( ! ,encyclopdia ,britannica1 we h ,maxwell's lat] views on ! fundam5tal assumptions ( ! molecul> !ory4 ,! text-book on 8,heat0 conta9s "s fur!r developm5ts ( ! !ory4 ,9 p>ticul> he %[s h[ ! conclusions ( ! second law ( !rmo-dynamics are connect$ ) ! fact t ! co>s5ess ( our faculties w n all[ u to grapple ) individual molecules4 ,! "w describ$ 9 ! =ego+ *apt]s w\ld h be5 suffici5t to secure to ,maxwell a di/+ui%$ place among ^? :o h advanc$ our k2 x rema9s /ill to describe 8 greate/ "w1 8 !ory ( ,electricity & ,magnetism4 ,,*apt] ,,ix4 ,,sci5tific ,,"w4--,,electrical ,,!ories4 ,cl]k ,maxwell's fir/ electrical pap]--t on ,f>aday's 8,l9es ( ,=ce0--0 read to ! ,cambridge ,philosophical ,society on ,decemb] #aj?1 #ahee1 & ,"p ,,ii4 on ,febru>y #aa?1 #ahef4 ,! au?or 0 !n a ,ba*elor ( ,arts1 only tw5ty-?ree ye>s 9 age1 & ( less ?an "o ye>'s /&+ f ! "t ( tak+ 8 degree4 ,! op5+ words ( ! pap] are z foll[s 7,sci5tific ,pap]s1 vol4 i41 p4 #aee73-- 8,! pres5t /ate ( electrical sci5ce seems peculi>ly unfav\rable to speculation4 ,! laws ( ! di/ribution ( electricity on ! surface ( conductors h be5 analytically d$uc$ f exp]im5t2 "s p>ts ( ! ma!matical !ory ( magnetism are e/abli%$1 :ile 9 o!r p>ts ! exp]im5tal data are want+2 ! !ory ( ! conduction ( galvanism1 & t ( ! mutual attraction ( conductors1 h be5 r$uc$ to ma!matical =mul1 b h n fall5 into relation ) ! o!r p>ts ( ! sci5ce4 ,no electrical !ory c n[ be put =?1 unless x %[s ! connection1 n only betwe5 electricity at re/ & curr5t electricity1 b betwe5 ! attractions & inductive effects ( electricity 9 bo? /ates4 ,su* a !ory mu/ accurately satisfy ^? laws1 ! ma!matical =m ( :i* is kn[n1 & mu/ af=d ! means ( calculat+ ! effects 9 ! limit+ cases :]e ! kn[n =mul are inapplicable4 ,9 ord]1 !re=e1 to appreciate ! requirem5ts ( ! sci5ce1 ! /ud5t mu/ make himself famili> ) a consid]able body ( mo/ intricate ma!matics1 ! m]e ret5tion ( :i* 9 ! memory mat]ially int]f]es ) fur!r progress4 ,! fir/ process1 !re=e1 9 ! effectual /udy ( ! sci5ce1 mu/ be "o ( simplification & r$uction ( ! results ( previ\s inve/igation to a =m 9 :i* ! m9d c grasp !m4 ,! results ( ?is simplification may take ! =m ( a purely ma!matical =mula or ( a physical hypo!sis4 ,9 ! fir/ case we entirely lose sight ( ! ph5om5a to be expla9$2 & ?\gh we may trace out ! consequ5ces ( giv5 laws1 we c nev] obta9 m ext5d$ views ( ! connections ( ! subject4 ,if1 on ! o!r h&1 we adopt a physical hypo!sis1 we see ! ph5om5a only ?r\gh a m$ium1 & are liable to t bl9dness to facts & ra%ness 9 assumption :i* a p>tial explanation enc\rages4 ,we mu/ !re=e discov] "s me?od ( inve/igation :i* all[s ! m9d at e /ep to lay hold ( a cle> physical conception1 )\t be+ committ$ to any !ory f\nd$ on ! physical sci5ce f :i* t conception is borr[$1 s t x is nei!r drawn aside f ! subject 9 pursuit ( analytical subtleties1 nor c>ri$ beyond ! tru? by a fav\rite hypo!sis4 8,9 ord] to obta9 physical ideas )\t adopt+ a physical !ory we mu/ make ourselves famili> ) ! exi/5ce ( physical analogies4 ,by a physical analogy ,i mean t p>tial simil>ity betwe5 ! laws ( "o sci5ce & ^? ( ano!r :i* makes ea* ( !m illu/rate ! o!r4 ,?us all ! ma!matical sci5ces are f\nd$ on relations betwe5 physical laws & laws ( numb]s1 s t ! aim ( exact sci5ce is to r$uce ! problems ( ,nature to ! det]m9ation ( quantities by op]ations ) memb]s4 ,pass+ f ! mo/ univ]sal ( all analogies to a v p>tial "o1 we f9d ! same resemblance 9 ma!matical =m betwe5 two diff]5t ph5om5a giv+ rise to a physical !ory ( light4 8,! *anges ( direction :i* light und]goes 9 pass+ f "o m$ium to ano!r are id5tical ) ! deviations ( ! pa? ( a p>ticle 9 mov+ ?r\gh a n>r[ space 9 :i* int5se =ces act4 ,?is analogy1 :i* ext5ds only to ! direction1 & n to ! velocity ( motion1 0 long believ$ to be ! true explanation ( ! refraction ( light2 & we /ill f9d x useful 9 ! solution ( c]ta9 problems1 9 :i* we employ x )\t dang] z an artificial me?od4 ,! o!r analogy1 betwe5 light & ! vibrations ( an ela/ic m$ium1 ext5ds mu* f>!r1 b1 ?\gh its importance & fruitfulness _c be ov]-e/imat$1 we mu/ recollect t x is f\nd$ only on a resemblance 9 =m betwe5 ! laws ( light & ^? ( vibrations4 ,by /ripp+ x ( its physical dress & r$uc+ x to a !ory ( #8transv]se alt]nations1' we might obta9 a sy/em ( tru? /rictly f\nd$ on obs]vation1 b probably defici5t bo? 9 ! vividness ( its conceptions & ! f]tility ( its me?od4 ,i h said ?us mu* on ! disput$ que/ions ( optics1 z a prep>ation = ! discussion ( ! almo/ univ]sally admitt$ !ory ( attraction at a di/ance4 8,we h all acquir$ ! ma!matical conception ( ^! attractions4 ,we c reason ab\t !m & det]m9e _! appropriate =ms or =mul4 ,^! =mul h a di/9ct ma!matical significance1 & _! results are f\nd to be 9 accordance ) natural ph5om5a4 ,!re is no =mula 9 appli$ ma!matics m consi/5t ) ,nature ?an ! =mula ( attractions1 & no !ory bett] e/abli%$ 9 ! m9ds ( m5 ?an t ( ! action ( bodies on "o ano!r at a di/ance4 ,! laws ( ! conduction ( heat 9 uni=m m$ia appe> at fir/ sight among ! mo/ diff]5t 9 _! physical relations f ^? relat+ to attractions4 ,! quantities :i* ent] into !m are temp]ature1 fl[ ( heat1 conductivity4 ,! ^w =ce is =eign to ! subject4 ,yet we f9d t ! ma!matical laws ( ! uni=m motion ( heat 9 homog5e\s m$ia are id5tical 9 =m ) ^? ( attractions v>y+ inv]sely z ! squ>e ( ! di/ance4 ,we h only to sub/itute s\rce ( heat = c5tre ( attraction1 fl[ ( heat = accel]at+ effect ( attraction at any po9t1 & temp]ature = pot5tial1 & ! solution ( a problem 9 attractions is trans=m$ into t ( a problem 9 heat4 8,?is analogy betwe5 ! =mul ( heat & attraction 01 ,i believe1 fir/ po9t$ out by ,pr(essor ,william ,?omson 9 ! ,cambridge ,ma!matical ,j\rnal1 ,vol4 ,,iii4 8,n[ ! conduction ( heat is suppos$ to proce$ by an action betwe5 contigu\s p>ts ( a m$ium1 :ile ! =ce ( attraction is a relation betwe5 di/ant bodies1 & yet1 if we knew no?+ m ?an is express$ 9 ! ma!matical =mul1 !re w\ld be no?+ to di/+ui% betwe5 ! "o set ( ph5om5a & ! o!r4 8,x is true t1 if we introduce o!r consid]ations & obs]ve additional facts1 ! two subjects w assume v diff]5t aspects1 b ! ma!matical resemblance ( "s ( _! laws w rema91 & may /ill be made useful 9 excit+ appropriate ma!matical ideas4 8,x is by ! use ( analogies ( ?is k9d t ,i h attempt$ to br+ be=e ! m9d1 9 a conv5i5t & manageable =m1 ^? ma!matical ideas :i* are necess>y to ! /udy ( ! ph5om5a ( electricity4 ,! me?ods are g5]ally ^? sugge/$ by ! processes ( reason+ :i* are f\nd 9 ! rese>*es ( ,f>aday1 & :i*1 ?\gh !y h be5 int]pret$ ma!matically by ,pr(essor ,?omson & o!rs1 are v g5]ally suppos$ to be ( an indef9ite & unma!matical "*1 :5 comp>$ ) ^? employ$ by ! pr(ess$ ma!maticians4 ,by ! me?od :i* ,i adopt1 ,i hope to r5d] x evid5t t ,i am n attempt+ to e/abli% any physical !ory ( a sci5ce 9 :i* ,i h h>dly made a s+le exp]im5t1 & t ! limit ( my design is to %[ h[1 by a /rict application ( ! ideas & me?ods ( ,f>aday1 ! connection ( ! v diff]5t ord]s ( ph5om5a :i* he has discov]$ may be cle>ly plac$ be=e ! ma!matical m9d4 ,i %all !re=e avoid z mu* z ,i c ! introduction ( any?+ :i* does n s]ve z a direct illu/ration ( ,f>aday's me?ods1 or ( ! ma!matical d$uctions :i* may be made f !m4 ,9 treat+ ! simpl] p>ts ( ! subject ,i %all use ,f>aday's ma!matical me?ods z well z 8 ideas4 ,:5 ! complexity ( ! subject requires x1 ,i %all use analytical notation1 /ill conf9+ myself to ! developm5t ( ideas orig9at$ by ! same philosoph]4 8,i h 9 ! fir/ place to expla9 & illu/rate ! idea ( #8l9es ( =ce4' 8,:5 a body is electrifi$ 9 any mann]1 a small body *>g$ ) positive electricity1 & plac$ 9 any giv5 position1 w exp]i5ce a =ce urg+ x 9 a c]ta9 direction4 ,if ! small body be n[ negatively electrifi$1 x w be urg$ by an equal =ce 9 a direction exactly opposite4 8,! same relations hold betwe5 a magnetic body & ! nor? or s\? poles ( a small magnet4 ,if ! nor? pole is urg$ 9 "o direction1 ! s\? pole is urg$ 9 ! opposite direction4 8,9 ?is way we might f9d a l9e pass+ ?r\gh any po9t ( space1 su* t x repres5ts ! direction ( ! =ce act+ on a positively electrifi$ p>ticle1 or on an elem5t>y nor? pole1 & ! rev]se direction ( ! =ce on a negatively electrifi$ p>ticle or an elem5t>y s\? pole4 ,s9ce at e po9t ( space su* a direction may be f\nd1 if we comm5ce at any po9t & draw a l9e s t1 z we g along x1 its direction at any po9t %all always co9cide ) t ( ! resultant =ce at t po9t1 ?is curve w indicate ! direction ( t =ce = e po9t ?r\gh :i* x passes1 & might be call$ on t acc\nt a l9e ( =ce4 ,we might 9 ! same way draw o!r l9es ( =ce1 till we _h fill$ all space ) curves indicat+ by _! direction t ( ! =ce at any assign$ po9t4 8,we %\ld ?us obta9 a geometrical model ( ! physical ph5om5a1 :i* w\ld tell u ! direction ( ! =ce1 b we %\ld /ill require "s me?od ( indicat+ ! int5sity ( ! =ce at any po9t4 ,if we consid] ^! curves n z m]e l9es1 b z f9e tubes ( v>iable section c>ry+ an incompressible fluid1 !n1 s9ce ! velocity ( ! fluid is inv]sely z ! section ( ! tube1 we may make ! velocity v>y accord+ to any giv5 law1 by regulat+ ! section ( ! tube1 & 9 ?is way we might repres5t ! int5sity ( ! =ce z well z its direction by ! motion ( ! fluid 9 ^! tubes4 ,?is me?od ( repres5t+ ! int5sity ( a =ce by ! velocity ( an imag9>y fluid 9 a tube is applicable to any conceivable sy/em ( =ces1 b x is capable ( great simplification 9 ! case 9 :i* ! =ces are su* z c be expla9$ by ! hypo!sis ( attractions v>y+ inv]sely z ! squ>e ( ! di/ance1 su* z ^? obs]v$ 9 electrical & magnetic ph5om5a4 ,9 ! case ( a p]fectly arbitr>y sy/em ( =ces1 !re w g5]ally be int]/ices betwe5 ! tubes2 b 9 ! case ( electric & magnetic =ces x is possible to arrange ! tubes s z to leave no int]/ices4 ,! tubes w !n be m]e surfaces1 direct+ ! motion ( a fluid fill+ up ! :ole space4 ,x has be5 usual to comm5ce ! inve/igation ( ! laws ( ^! =ces by at once assum+ t ! ph5om5a are due to attractive or repulsive =ces act+ betwe5 c]ta9 po9ts4 ,we may1 h[ev]1 obta9 a diff]5t view ( ! subject1 & "o m suit$ to our m difficult inquiries1 by adopt+ = ! def9ition ( ! =ces ( :i* we treat1 t !y may be repres5t$ 9 magnitude & direction by ! uni=m motion ( an incompressible fluid4 8,i propose1 !n1 fir/ to describe a me?od by :i* ! motion ( su* a fluid c be cle>ly conceiv$2 secondly to trace ! consequ5ces ( assum+ c]ta9 conditions ( motion1 & to po9t out ! application ( ! me?od to "s ( ! less complicat$ ph5om5a ( electricity1 magnetism1 & galvanism2 & la/ly1 to %[ h[ by an ext5sion ( ^! me?ods1 & ! introduction ( ano!r idea due to ,f>aday1 ! laws ( ! attractions & inductive actions ( magnets & curr5ts may be cle>ly conceiv$1 )\t mak+ any assumptions z to ! physical nature ( electricity1 or add+ any?+ to t :i* has be5 already prov$ by exp]im5t4 8,by ref]r+ ev]y?+ to ! purely geometrical idea ( ! motion ( an imag9>y fluid1 ,i hope to atta9 g5]ality & precision1 & to avoid ! dang]s aris+ f a premature !ory pr(ess+ to expla9 ! cause ( ! ph5om5a4 ,if ! results ( m]e speculation :i* ,i h collect$ are f\nd to be ( any use to exp]im5tal philosoph]s1 9 arrang+ & int]pret+ _! results1 !y w h s]v$ _! purpose1 & a mature !ory1 9 :i* physical facts w be physically expla9$1 w be =m$ by ^? :o by int]rogat+ ,nature h]self c obta9 ! only true solution ( ! que/ions :i* ! ma!matical !ory sugge/s40 ,! idea 0 a bold "o3 = a y\? ( tw5ty-?ree to expla91 by means ( ! motions ( an incompressible fluid1 "s ( ! less complicat$ ph5om5a ( electricity & magnetism1 to %[ h[ ! laws ( ! attractions ( magnets & curr5ts may be cle>ly conceiv$ )\t mak+ any assumption z to ! physical nature ( electricity1 or add+ any?+ to t :i* has already be5 prov$ by exp]im5t4 ,x may be useful to review 9 a v few words ! position ( electrical !ory#eg 9 #ahee4 ,c\lomb's exp]im5ts _h e/abli%$ ! fundam5tal facts ( electro/atic attraction & repulsion1 & ,c\lomb himself1 ab\t #aghe1 _h /at$ a !ory bas$ on ^! exp]im5ts :i* c\ld 8only be attack$ by prov+ 8 exp]im5tal results to be inaccurate40#eh ,c\lomb supposes ! exi/5ce ( two electric fluids1 ! !ory develop$ previ\sly by ,frankl91 b says-- 8,je prvi5s p\r mettre la ?orie qui va suivre l'abri de t\te dispute sy/matique1 que dans la supposition de deux fluides lectriques1 je n'ai autre int5tion que de prs5t] avec le mo9s d'lm5ts possible les rsultats du calcul et de l'expri5ce1 et non d'indiqu] les vritables causes de l'lectricit40 ,cav5di% 0 work+ 9 ,engl& ab\t ! same "t z ,c\lomb1 b he publi%$ v little1 & ! value & importance ( 8 "w 0 n recognis$ until ! appe>ance 9 #ahgi ( ! 8,electrical ,rese>*es ( ,h5ry ,cav5di%10 edit$ by ,cl]k ,maxwell4 ,e>ly 9 ! pres5t c5tury ! application ( ma!matical analysis to electrical problems 0 begun by ,laplace1 :o inve/igat$ ! di/ribution ( electricity on sph]oids1 & ab\t #ahaa ,poisson's great "w on ! di/ribution ( electricity on two sph]es plac$ at any giv5 di/ance ap>t 0 publi%$4 ,mean:ile ! prop]ties ( ! electric curr5t 7 be+ inve/igat$4 ,galvani's discov]y ( ! muscul> contraction 9 a frog's leg1 caus$ by ! contact ( dissimil> metals1 0 made 9 #agij4 ,volta inv5t$ ! voltaic pile 9 #ahjj1 & ,o]/$ 9 #ahbj discov]$ t an electric curr5t produc$ magnetic =ce 9 its neighb\rhood4 ,on ?is ,ampre laid ! f\ndation ( 8 !ory ( electro-dynamics1 9 :i* he %[$ h[ to calculate ! =ces betwe5 circuits c>ry+ curr5ts f an assum$ law ( =ce betwe5 ea* pair ( elem5ts ( ! circuits4 ,8 exp]im5ts prov$ t ! consequ5ces :i* foll[ f ?is law are consi/5t ) all ! obs]v$ facts4 ,!y d n prove t ,ampre's law alone c expla9 ! facts4 ,maxwell1 writ+ on ?is subject 9 ! 8,electricity an ,magnetism10 vol4 ii41 p4 #afb1 says-- 8,! exp]im5tal inve/igation by :i* ,ampre e/abli%$ ! laws ( ! me*anical action betwe5 electric curr5ts is "o ( ! mo/ brilliant a*ievem5ts 9 sci5ce4 8,! :ole1 !ory & exp]im5t1 seems z if x _h leap$ full gr[n & full arm$ f ! bra9 ( ! #8,newton ( ,electricity4' ,x is p]fect 9 =m & unassailable 9 accuracy1 & x is summ$ up 9 a =mula f :i* all ! ph5om5a may be d$uc$1 & :i* mu/ always rema9 ! c>d9al =mula ( electro-dynamics4 8,! me?od ( ,ampre1 h[ev]1 ?\gh ca/ into an inductive =m1 does n all[ u to trace ! =mation ( ! ideas :i* guid$ x4 ,we c sc>cely believe t ,ampre really discov]$ ! law ( action by means ( ! exp]im5ts :i* he describes4 ,we are l$ to suspect1 :at1 inde$1 he tells u himself1 t he discov]$ ! law by "s process :i* he has n %[n u1 & t :5 he _h aft]w>ds built up a p]fect demon/ration1 he remov$ all traces ( ! scaffold+ by :i* he _h built x40 ,! exp]im5tal evid5ce = ,ampre's !ory1 s f>1 at lea/1 z x 0 possible to obta9 x f exp]im5ts on clos$ circuits1 0 r5d]$ unimpea*able by ,w4 ,web] ab\t #ahdf1 :ile 9 ! previ\s ye> ,grassman & ,f4 ,e4 ,neumann bo? publi%$ laws = ! attraction betwe5 two elem5ts ( curr5t :i* diff] f t ( ,ampre1 b lead to ! same result = clos$ circuits4 ,9 a pap] publi%$ 9 #ahdf ,web] ann\nc$ 8 hypo!sis connect+ toge!r electro/atic & electro-dynamic action4 ,9 ?is pap] he suppos$ t ! =ce betwe5 two p>ticles ( electricity dep5ds on ! motion ( ! p>ticles z well z on _! di/ance ap>t4 ,a some:at simil> !ory 0 propos$ by ,gauss & publi%$ aft] 8 dea? 9 8 collect$ works4 ,x has be5 %[n1 h[ev]1 t ,gauss' !ory is inconsi/5t ) ! cons]vation ( en]gy4 ,web]'s !ory avoids ?is inconsi/5cy & leads1 = clos$ circuits1 to ! same results z ,ampre4 ,x has be5 prov$1 h[ev]1 by ,von ,helmholtz1 t1 "u c]ta9 circum/ances1 accord+ to x1 a body w\ld behave z ?\gh its mass 7 negative--x w\ld move 9 a direction opposite to t ( ! =ce4#ei ,s9ce #ahdf _m o!r !ories h be5 propos$ to expla9 ,ampre's laws4 ,mean:ile1 9 #ahba1 ,f>aday obs]v$ t "u c]ta9 circum/ances a wire c>ry+ a curr5t c\ld be kept 9 cont9u\s rotation 9 a magnetic field by ! action betwe5 ! magnets & ! curr5t4 ,9 #ahbd ,arago obs]v$ ! motion ( a magnet caus$ by rotat+ a copp] disc 9 its neighb\rhood1 :ile 9 #ahca ,f>aday began 8 exp]im5tal rese>*es into electro-magnetic induction4 ,ab\t ! same p]iod ,joseph ,h5ry1 ( ,wa%+ton1 0 mak+1 indep5d5tly ( ,f>aday1 exp]im5ts ( fundam5tal importance on electro-magnetic induction1 b suffici5t att5tion 0 n call$ to 8 "w until comp>atively rec5t ye>s4 ,9 #ahcc ,l5z made "s important rese>*es1 :i* l$ him to discov] ! connection betwe5 ! direction ( ! induc$ curr5ts & ,ampre's laws1 summ$ up 9 8 rule t ! direction ( ! induc$ curr5t is always su* z to oppose by its electro-magnetic action ! motion :i* induces x4 ,9 #ahde ,f4 ,e4 ,neumann develop$ f ?is law ! ma!matical !ory ( electro-magnetic induction1 & ab\t ! same "t ,w4 ,web] %[$ h[ x might be d$uc$ f 8 elem5t>y law ( electrical action4 ,! great "n ( ,von ,helmholtz fir/ appe>s 9 connection ) ?is subject 9 #ahea1 b ( 8 writ+s we %all h m to say at a lat] /age4 ,mean:ile1 dur+ ! same p]iod1 v>i\s writ]s1 ,murphy1 ,plana1 ,*>les1 ,/urm1 & ,gauss1 ext5d$ ,poisson's "w on electro/atics1 treat+ ! que/ions :i* arose z problems 9 ! di/ribution ( an attract+ fluid1 attract+ or repell+ accord+ to ,newton's law1 ?\gh "h aga9 ! greate/ advances 7 made by a self-taught ,nott+ham %oemak]1 ,george ,gre5 by "n1 9 8 pap] 8,on ! ,application ( ,ma!matical ,analysis to ! ,!ories ( ,electricity & ,magnetism10 #ahbh4 ,gre5's rese>*es1 ,"l ,kelv9 writes1 8h l$ to ! elem5t>y proposition :i* mu/ con/itute ! legitimate f\ndation ( e p]fect ma!matical /ructure t is to be made f ! mat]ials furni%$ by ! exp]im5tal laws ( ,c\lomb40 ,gre51 x may be rem>k$1 0 ! inv5tor ( ! t]m ,pot5tial4 ,8 essay1 h[ev]1 lay neglect$ f #ahbh1 until ,"l ,kelv9 call$ att5tion to x 9 #ahde4 ,mean:ile1 "s ( its mo/ important results _h be5 re-discov]$ by ,gauss & ,*>les & ,?omson himself4 ,until ab\t #ahde1 ! exp]im5tal "w on :i* ^! ma!matical rese>*es 9 electro/atics 7 bas$ 0 t ( ,c\lomb4 ,an electrifi$ body is suppos$ to h a *>ge ( "s impond]able fluid 8electricity40 ,p>ticles ( electricity repel ea* o!r accord+ to a c]ta9 law1 & ! fluid di/ributes itself 9 equilibrium ov] ! surface ( any *>g$ conductor 9 accordance ) ?is law4 ,!re are on ?is !ory two opposite k9ds ( electric fluid1 positive & negative1 two *>ges ( ! same k9d repel1 two *>ges ( opposite k9ds attract2 ! repulsion or attraction is proportional to ! product ( ! *>ges1 & inv]sely proportional to ! squ>e ( ! di/ance betwe5 !m4 ,! action betwe5 two *>ges is action at a di/ance tak+ place across ! space :i* sep>ates ! two4 ,f>aday1 9 #ahcg1 9 ! elev5? s]ies ( 8 8,exp]im5tal ,rese>*es10 publi%$ 8 fir/ pap] on 8,electro/atic ,induction40 ,he %[$--z inde$ ,cav5di% _h prov$ long previ\sly1 ?\gh ! result rema9$ unpubli%$--t ! =ce betwe5 two *>g$ bodies w dep5d on ! insulat+ m$ium :i* surr\nds !m1 n m]ely on _! %ape & position4 ,induction1 z he expresses x1 takes place along curv$ l9es1 & is an action ( contigu\s p>ticles2 ^! curv$ l9es he calls ! 8l9es ( =ce40 ,discuss+ ^! rese>*es 9 #ahde1 ,"l ,kelv9 writes#fj3-- 8,mr4 ,f>aday's rese>*es 444 7 und]tak5 ) a view to te/ an idea :i* he _h long possess$ t ! =ces ( attraction & repulsion ex]cis$ by free electricity are n ! resultants ( actions ex]cis$ at a di/ance1 b are propagat$ by means ( molecul> action among ! contigu\s p>ticles ( ! insulat+ m$ium surr\nd+ ! electrifi$ bodies1 :i* he !re=e calls ! dielectric4 ,by ?is idea he has be5 l$ to "s v rem>kable views ^u induction1 or1 9 fact1 ^u electrical action 9 g5]al4 ,z x is impossible t ! ph5om5a obs]v$ by ,f>aday c be incompatible ) ! results ( exp]im5t :i* con/itute ,c\lomb's !ory1 x is to be expect$ t ! diff]5ce ( 8 ideas f ^? ( ,c\lomb mu/ arise solely f a diff]5t me?od ( /at+ & int]pret+ physically ! same laws2 & fur!r1 x may1 ,i ?9k1 be %[n t ei!r me?od ( view+ ?is subject1 :5 c>ri$ suffici5tly f>1 may be made ! f\ndation ( a ma!matical !ory :i* w\ld lead to ! elem5t>y pr9ciples ( ! o!r z consequ5ces4 ,?is !ory w\ld1 accord+ly1 be ! expression ( ! ultimate law ( ! ph5om5a1 indep5d5tly ( any physical hypo!sis we might f o!r circum/ances be l$ to adopt4 ,t !re are necess>ily two di/9ct elem5t>y ways ( view+ ! !ory ( electricity may be se5 f ! foll[+ consid]ations44440 ,9 ! pages :i* foll[1 ,"l ,kelv9 develops ! consequ5ces ( an analogy betwe5 ! conduction ( heat & electro/atic action1 :i* he _h po9t$ out ?ree ye>s e>li] 7#ahdb71 9 8 pap] on 8,! ,uni=m ,motion ( ,heat 9 ,homog5e\s ,solid ,bodies10 & discusses its connection ) ! ma!matical !ory ( electricity4 ,! problem ( di/ribut+ s\rces ( heat 9 a giv5 homog5e\s conductor ( heat1 s z to produce a def9ite /eady temp]ature at ea* po9t on ! conductor is %ewn to be ma!matically id5tical ) t ( di/ribut+ electricity 9 equilibrium1 s z to produce at ea* po9t an electrical pot5tial hav+ ! same value z ! temp]ature4 ,?us ! fundam5tal laws ( ! conduction ( heat may be made ! basis ( ! ma!matical !ory ( electricity1 b ! physical idea :i* !y sugge/ is t ( ! propagation ( "s effect by means ( ! mutual action ( contigu\s p>ticles1 r ?an t ( mat]ial p>ticles attract+ or repell+ at a di/ance1 :i* naturally foll[s f ! /atem5t ( ,c\lomb's law4 ,"l ,kelv9 cont9ues3-- 8,all ! views :i* ,f>aday has br\ght =w>d & illu/rat$1 z demon/rat$ by exp]im5t1 lead to ?is me?od ( e/abli%+ ! ma!matical !ory1 &1 z f> z ! analysis is conc]n$1 x w\ld 9 mo/ g5]al propositions be m simple1 if possible1 ?an t ( ,c\lomb4 ,( c\rse ! analysis ( p>ticul> problems w\ld be id5tical 9 ! two me?ods4 ,x is ?us t ,f>aday arrives at a k ( "s ( ! mo/ important ( ! ma!matical !orems :i* f _! nature seem$ de/9$ nev] to be p]ceiv$ except z ma!matical tru?s40 ,"l ,kelv9's pap]s on 8,! ,ma!matical ,!ory ( ,electricity10 publi%$ f #ahdh to #ahej1 8 8,propositions on ! ,!ory ( ,attraction0 7#ahdb71 8 8,!ory ( ,electrical ,images0 7#ahdg71 & 8 pap] on 8,! ,ma!matical ,!ory ( ,magnetism0 7#ahdi71 conta9 a /atem5t ( ! mo/ important results a*iev$ 9 ! ma!matical sci5ces ( ,electro/atics & ,magnetism up to ! "t ( ,maxwell's fir/ pap]4 ,! op5+ s5t5ces ( t pap] h already be5 quot$4 ,9 ! preface to ! 8,electricity & ,magnetism0 ,maxwell writes ?us3-- 8,be=e ,i began ! /udy ( electricity ,i resolv$ to read no ma!matics on ! subject till ,i _h fir/ read ?r\gh #8,exp]im5tal ,rese>*es on ,electricity4' ,i 0 aw>e t !re 0 suppos$ to be a diff]5ce betwe5 ,f>aday's way ( conceiv+ ph5om5a & t ( ! ma!maticians1 s t nei!r he nor !y 7 satisfi$ ) ea* o!r's language4 ,i _h also ! conviction t ?is discrepancy did n arise f ei!r p>ty be+ wrong4 ,i 0 fir/ conv9c$ ( ?is by ,sir ,william ,?omson1 to ^: advice & assi/ance1 z well z to 8 publi%$ pap]s1 ,i owe mo/ ( :at ,i h le>n$ on ! subject4 8,z ,i proce$$ ) ! /udy ( ,f>aday1 ,i p]ceiv$ t 8 me?od ( conceiv+ ! ph5om5a 0 also a ma!matical "o1 ?\gh n exhibit$ 9 ! conv5tional =m ( ma!matical symbols4 ,i also f\nd t ^! me?ods 7 capable ( be+ express$ 9 ! ord9>y ma!matical =ms1 & ?us comp>$ ) ^? ( ! pr(ess$ ma!maticians4 8,= in/ance1 ,f>aday1 9 8 m9d's eye1 saw l9es ( =ce trav]s+ all space :]e ! ma!maticians saw c5tres ( =ce attract+ at a di/ance4 ,f>aday saw a m$ium :]e !y saw no?+ b di/ance4 ,f>aday s\ght ! seat ( ! ph5om5a 9 real actions go+ on 9 ! m$ium4 ,!y 7 satisfi$ t !y _h f\nd x 9 a p[] ( action at a di/ance impress$ on ! electric fluids40 ,n[1 ,maxwell saw an analogy betwe5 electro/atics & ! /eady motion ( an incompressible fluid l wat]1 & x is ?is analogy :i* he develops 9 ! fir/ "p ( 8 pap]4 ,! wat] fl[s along def9ite l9es2 a surface :i* consi/s :olly ( su* l9es ( fl[ w h ! prop]ty t no wat] ev] crosses x4 ,9 any /ream ( wat] we c imag9e a numb] ( su* surfaces drawn1 divid+ x up into a s]ies ( tubes2 ea* ( ^! w be a tube ( fl[1 ea* ( ^! tubes rema9 always fill$ ) wat]4 ,h5ce1 ! quantity ( wat] :i* crosses p] second any section ( a tube ( fl[ p]p5dicul> to its l5g? is always ! same4 ,?us1 f ! =m ( ! tube1 we c obta9 in=mation z to ! direction & /r5g? ( ! fl[1 = :]e ! tube is wide ! fl[ w be proportionately small1 & vice v]s4 ,aga91 we c draw 9 ! fluid a numb] ( surfaces1 ov] ea* ( :i* ! pressure is ! same2 ^! surfaces w cut ! tubes ( fl[ at "r angles4 ,let u suppose !y are drawn s t ! diff]5ce ( pressure betwe5 any two consecutive surfaces is unity1 !n ! surfaces w be close toge!r at po9ts at :i* ! pressure *anges rapidly2 :]e ! v>iation ( pressure is sl[1 ! di/ance betwe5 two consecutive surfaces w be consid]able4 ,if1 !n1 9 any case ( motion1 we c draw ! pressure surfaces1 & ! tubes ( fl[1 we c det]m9e ! motion ( ! fluid completely4 ,n[1 ! same ma!matical expressions :i* appe> 9 ! hydro-dynamical !ory occur also 9 ! !ory ( electricity1 ! mean+ only ( ! symbols is *ang$4 ,= velocity ( fluid we h to write electrical =ce4 ,= diff]5ce ( fluid pressure we sub/itute "w done1 or diff]5ce ( electrical pot5tial or pressure4 ,! surfaces & tubes1 drawn z ! solution ( any hydro-dynamical problem1 give u also ! solution ( an electrical problem2 ! tubes ( fl[ are ,f>aday's tubes ( =ce1 or tubes ( induction1 ! surfaces ( con/ant pressure are surfaces ( equal electrical pot5tial4 ,induction may take place 9 curv$ l9es j z ! tubes ( fl[ may be b5t & curv$2 ! analogy betwe5 ! two is a complete "o4 ,b1 z ,maxwell %[s1 ! analogy rea*es fur!r /ill4 ,an electric curr5t fl[+ along a wire _h be5 recognis$ z hav+ _m prop]ties simil> to ^? ( a curr5t ( liquid 9 a tube4 ,:5 a /eady curr5t is pass+ ?r\gh any solid conductor1 !re are =m$ 9 ! conductor tubes ( electrical fl[ & surfaces ( con/ant pressure4 ,^! tubes & surfaces are ! same z ^? =m$ by ! fl[ ( liquid ?r\gh a solid ^: b\nd>y surface is ! same z t ( ! conductor1 provid$ ! fl[ ( liquid is prop]ly proportion$ to ! fl[ ( electricity4 ,^! analogies ref] to /eady curr5ts 9 :i*1 !re=e1 ! fl[ at any po9t ( ! conductor does n dep5d on ! "t4 ,9 ,"p ,,ii4 ( 8 pap] ,maxwell deals ) ,f>aday's electro-tonic /ate4 ,f>aday _h f\nd t :5 *anges are produc$ 9 ! magnetic ph5om5a surr\nd+ a conductor1 an electric curr5t is set up 9 ! conductor1 :i* cont9ues s long z ! magnetic *anges are 9 progress1 b :i* ceases :5 ! magnetic /ate becomes /eady4 8,consid]ations ( ?is k9d l$ ,pr(essor ,f>aday to connect ) 8 discov]y ( ! induction ( electric curr5ts ! conception ( a /ate into :i* all bodies are ?r[n by ! pres5ce ( magnets & curr5ts4 ,?is /ate does n manife/ itself by any kn[n ph5om5a z long z x is undi/urb$1 b any *ange 9 ?is /ate is indicat$ by a curr5t or t5d5cy t[>ds a curr5t4 ,to ?is /ate he gave ! "n ( ! #8,electro-tonic ,/ate1' & al?\gh he aft]w>ds succe$$ 9 expla9+ ! ph5om5a :i* sugge/$ x by means ( less hypo!tical conceptions1 he has on sev]al occasions h9t$ at ! probability t "s ph5om5a might be discov]$ :i* w\ld r5d] ! electro-tonic /ate an object ( legitimate induction4 ,^! speculations1 into :i* ,f>aday _h be5 l$ by ! /udy ( laws :i* he has well e/abli%$1 & :i* he ab&on$ only = want ( exp]im5tal data = ! direct pro( ( ! unkn[n /ate1 h n1 ,i ?9k1 be5 made ! subject ( ma!matical inve/igation4 ,p]haps x may be ?\ght t ! quantitative det]m9ations ( ! v>i\s ph5om5a are n suffici5tly rigor\s to be made ! basis ( a ma!matical !ory4 ,f>aday1 h[ev]1 has n cont5t$ himself ) simply /at+ ! num]ical results ( 8 exp]im5ts & leav+ ! law to be discov]$ by calculation4 ,:]e he has p]ceiv$ a law he has at once /at$ x1 9 t]ms z unambigu\s z ^? ( pure ma!matics1 & if ! ma!matician1 receiv+ ?is z a physical tru?1 d$uces f x o!r laws capable ( be+ te/$ by exp]im5t1 he has m]ely assi/$ ! physici/ 9 arrang+ 8 own ideas1 :i* is confess$ly a necess>y /ep 9 sci5tific induction4 8,9 ! foll[+ inve/igation1 !re=e1 ! laws e/abli%$ by ,f>aday w be assum$ z true1 & x w be %[n t by foll[+ out 8 speculations o!r & m g5]al laws c be d$uc$ f !m4 ,if x %\ld1 !n1 appe> t ^! laws1 orig9ally devis$ to include "o set ( ph5om5a1 may be g5]alis$ s z to ext5d to ph5om5a ( a diff]5t class1 ^! ma!matical connections may sugge/ to physici/s ! means ( e/abli%+ physical connections1 & ?us m]e speculation may be turn$ to acc\nt 9 exp]im5tal sci5ce40 ,maxwell %[s h[ to obta9 a ma!matical expression = ,f>aday's electro-tonic /ate4 ,9 8 8,electricity & ,magnetism10 ?is electro-tonic /ate receives a new "n4 ,x is kn[n z ! ,vector ,pot5tial1#fa & ! pap] "u consid]ation conta9s1 ?\gh 9 an incomplete =m1 8 fir/ /atem5t ( ^? equations ( ! electric field :i* are s indissolubly b\nd up ) ,maxwell's "n4 ,! great advance 9 !ory made 9 ! pap] is ! di/9ct recognition ( c]ta9 ma!matical functions z repres5t+ ,f>aday's electrotonic-/ate1 & _! use 9 solv+ electro-magnetic problems4 ,! pap] conta9s no new physical !ory ( electricity1 b 9 a few ye>s "o appe>$4 ,9 8 lat] writ+s ,maxwell adopt$ a m g5]al view ( ! electro-magnetic field ?an t conta9$ 9 8 e>ly pap]s on 8,physical ,l9es ( ,=ce40 ,x mu/1 !re=e1 n be suppos$ t ! some:at gross conception ( cog-:eels & pulleys1 :i* we are ab\t to describe1 7 any?+ m to _! au?or ?an a model1 :i* enabl$ him to realise h[ ! *anges1 :i* occur :5 a curr5t ( electricity passes ?r\gh a wire1 might be repres5t$ by ! motion ( actual mat]ial p>ticles4 ,! problem be=e him 0 to devise a physical !ory ( electricity1 :i* w\ld expla9 ! =ces ex]t$ on electrifi$ bodies by means ( action betwe5 ! contigu\s p>ts ( ! m$ium 9 ! space surr\nd+ ^! bodies1 r ?an by direct action across ! di/ance :i* sep>ates !m4 ,a simil> "q1 /ill unansw]$1 _h aris5 9 ! case ( gravitation4 ,a/ronom]s h det]m9$ ! =ces betwe5 attract+ bodies2 !y d n "k h[ ^? =ces arise4 ,maxwell's fondness = models has already be5 allud$ to2 x _h l$ him to con/ruct 8 top to illu/rate ! dynamics ( a rigid body rotat+ ab\t a fix$ po9t1 & 8 model ( ,saturn's r+s 7n[ 9 ! ,cav5di% ,laboratory7 to illu/rate ! motion ( ! satellites 9 ! r+s4 ,he _h expla9$ _m ( ! gase\s laws by means ( ! impact ( molecules1 & n[ 8 f]tile +5uity 0 to imag9e a me*anical model ( ! /ate ( ! electro-magnetic field ne> a sy/em ( conductors c>ry+ curr5ts4 ,f>aday1 z we h se51 look$ ^u electro/atic & magnetic induction z tak+ place along curv$ l9es ( =ce4 ,he pictures ^! l9es z ropes ( molecules />t+ f a *>g$ conductor1 or a magnet1 z ! case may be1 & act+ on o!r bodies ne>4 ,^! ropes ( molecules t5d to %ort51 & at ! same "t to swell outw>ds lat]ally4 ,?us ! *>g$ conductor t5ds to draw o!r bodies to itself1 !re is a t5sion along ! l9es ( =ce1 :ile at ! same "t ea* tube ( molecules pu%es its neighb\rs aside2 a pressure at "r angles to ! l9es ( =ce is comb9$ ) ?is t5sion4 ,assum+ = a mom5t ?is pressure & t5sion to exi/1 c we devise a me*anism to acc\nt = x8 ,maxwell himself has lik5$ ! l9es ( =ce to ! fibres ( a muscle4 ,z ! fibres contract1 caus+ ! limb to :i* !y are atta*$ to move1 !y swell outw>ds1 & ! muscle ?ick5s4 ,aga91 f ano!r po9t ( view1 we might consid] a l9e ( =ce z consi/+ ( a /r+ ( small cells ( "s flexible mat]ial ea* fill$ ) fluid4 ,if we !n suppose ?is s]ies ( cells caus$ to rotate rapidly ab\t ! direction ( ! l9e ( =ce1 ! cells w exp& lat]ally & contract longitud9ally2 !re w aga9 be t5sion along ! l9es ( =ce & pressure at "r angles to !m4 ,x 0 ?is la/ idea1 z we %all see %ortly1 ( :i* ,maxwell made use-- 8,i propose n[0 he writes 78,on ,physical ,l9es ( ,=ce10 ,phil4 ,mag41 vol4 xxi47 8to exam9e magnetic ph5om5a f a me*anical po9t ( view1 & to det]m9e :at t5sions 91 or motions (1 a m$ium are capable ( produc+ ! me*anical ph5om5a obs]v$4 ,if by ! same hypo!sis we c connect ! ph5om5a ( magnetic attraction ) electro-magnetic ph5om5a1 & ) ^? ( induc$ curr5ts1 we %all h f\nd a !ory :i*1 if n true1 c only be prov$ to be errone\s by exp]im5ts1 :i* w greatly enl>ge our k ( ?is "p ( physics40 ,"l ,kelv9 _h 9 #ahdg giv5 a me*anical repres5tation ( electric1 magnetic & galvanic =ces by means ( ! displacem5ts ( an ela/ic solid 9 a /ate ( /ra94 ,! angul> displacem5t at ea* po9t ( ! solid 0 tak5 z proportional to ! magnetic =ce1 & f ?is ! relation betwe5 ! v>i\s o!r electric quantities & ! motion ( ! solid 0 develop$4 ,b ,"l ,kelv9 did n attempt to expla9 ! orig9 ( ! obs]v$ =ces by ! effects due to ^! /ra9s1 b m]ely made use ( ! ma!matical analogy to assi/ ! imag9ation 9 ! /udy ( bo?4 ,maxwell consid]$ magnetic action z exi/+ 9 ! =m ( pressure or t5sion1 or m g5]ally1 ( "s /ress 9 "s m$ium4 ,! exi/5ce ( a m$ium capable ( ex]t+ =ce on mat]ial bodies & ( )/&+ consid]able /ress1 bo? pressure & t5sion1 is ?us a fundam5tal hypo!sis ) him2 ?is m$ium is to be capable ( motion1 & electro-magnetic =ces arise f its motion & its /resses4 ,n[1 ,maxwell's fundam5tal supposition is t1 9 a magnetic field1 !re is a rotation ( ! molecules cont9ually 9 progress ab\t ! l9es ( magnetic =ce4 ,consid] n[ ! case ( a uni=m magnetic field1 ^: direction is p]p5dicul> to ! pap]2 we are to look ^u ! l9es ( =ce z p>allel /r+s ( molecules1 ! axes ( ^! /r+s be+ p]p5dicul> to ! pap]4 ,ea* /r+ is suppos$ to be rotat+ 9 ! same direction ab\t its axis1 & ! angul> velocity ( rotation is a measure ( ! magnetic =ce4 ,9 consequ5ce ( ?is rotation !re w be diff]5ces ( pressure 9 diff]5t directions 9 ! m$ium2 ! pressure along ! axes ( ! /r+s w be less ?an x w\ld be if ! m$ium 7 at re/1 t 9 ! directions at "r angles to ! axes w be great]1 ! m$ium w behave z ?\gh x 7 "u t5sion along ! axes ( ! molecules "u pressure at "r angles to !m4 ,moreov]1 x c be %[n t ! pressure & ! t5sion are bo? proportional to ! squ>e ( ! angul> velocity--! squ>e1 t is1 ( ! magnetic =ce--& ?is result is 9 accordance ) ! consequ5ces ( exp]im5t4 ,m elaborate calculation %[s t ?is /atem5t is true g5]ally4 ,if we draw ! l9es ( =ce 9 any magnetic field1 & !n suppose ! molecules ( ! m$ium set 9 rotation ab\t ^! l9es ( =ce z axes1 ) velocities :i* at ea* po9t are proportional to ! magnetic =ce1 ! di/ribution ( pressure ?r\gh\t is t :i* we "k actually to exi/ 9 ! magnetic field4 ,accord+ to ?is hypo!sis1 !n1 a p]man5t b> magnet has ! p[] ( sett+ ! m$ium r\nd x into cont9u\s molecul> rotation ab\t ! l9es ( =ce z axes4 ,! molecules :i* are set 9 rotation we may consid] z sph]ical1 or ne>ly sph]ical1 cells fill$ ) a fluid1 or an ela/ic solid sub/ance1 & surr\nd$ by a k9d ( membrane1 or sack1 hold+ ! cont5ts toge!r4 ,s f> ! model does n give any acc\nt ( electrical actions :i* g on 9 ! magnetic field4 ,! en]gy is :olly rotational1 & ! =ces :olly magnetic4 ,consid]1 h[ev]1 any two contigu\s /r+s ( molecules4 ,let !m cut ! pap] z %[n 9 ! two circles 9 ,fig4 #a3-- ,illu/ration3 ,fig4 #a4 ,fig4 #b4 ,!n ^! cells are bo? rotat+ 9 ! same direction1 h5ce at ,c1 :]e !y t\*1 _! po9ts ( contact w be mov+ 9 opposite directions1 z %[n by ! arr[ heads1 & x is difficult to imag9e h[ su* motion c cont9ue2 x w\ld require ! surfaces ( ! cells to be p]fectly smoo?1 & if ?is 7 s !y w\ld lose ! p[] ( transmitt+ action f "o cell to ! next4 ,! cells ,a & ,b may be comp>$ to two cog-:eels plac$ close toge!r1 :i* we wi% to turn 9 ! same direction4 ,if ! cogs c int]lock1 z 9 ,fig4 #b1 ?is is impossible3 consecutive :eels 9 ! tra9 mu/ move 9 opposite directions4 ,illu/ration3 ,fig4 #c4 ,b 9 _m ma*9es ! desir$ end is atta9$ by ins]t+ betwe5 ! two :eels ,a & ,b a ?ird idle :eel ,c1 z %ewn 9 ,fig4 #c4 ,?is may be v small1 its only function is to transmit ! motion ( ,a to ,b 9 su* a way t ,a & ,b may bo? turn 9 ! same direction4 ,x is n necess>y t !re %\ld be cogs on ! :eels2 if ! surfaces be p]fectly r\gh1 s t no slipp+ c take place1 ! same result foll[s )\t ! cogs4 ,guid$ by ?is analogy ,maxwell ext5d$ 8 model by suppos+ ea* cell coat$ ) a numb] ( small p>ticles :i* roll on its surface4 ,^! p>ticles play ! "p ( ! idle :eels 9 ! ma*9e1 & by _! roll+ m]ely enable ! adjac5t p>ts ( two cells to move 9 opposite directions4 ,consid] n[ a numb] ( su* cells & _! idle :eels ly+ 9 a plane1 t ( ! pap]1 & suppose ea* cell is rotat+ ) ! same uni=m angul> velocity ab\t an axis at "r angles to t plane1 ea* idle :eel w be act$ on by two equal & opposite =ces at ! ends ( ! diamet] 9 :i* x is t\*$ by ! adjac5t cells2 x w !re=e be set 9 rotation1 b !re w be no =ce t5d+ to drive x onw>ds2 x does n matt] :e!r ! axis on :i* x rotates is free to move or fix$1 9 ei!r case ! idle :eel simply rotates4 ,b suppose n[ ! adjac5t cells are n rotat+ at ! same rate4 ,9 addition to its rotation ! idle :eel w be urg$ onw>d ) a velocity :i* dep5ds on ! diff]5ce betwe5 ! rotations1 &1 if x c move freely1 x w move on f betwe5 ! two cells4 ,imag9e n[ t ! int]/ices betwe5 ! cells are fitt$ ) a /r+ ( idle :eels4 ,s long z ! adjac5t cells move ) diff]5t velocity !re w be a cont9ual /ream ( roll+ p>ticles or idle :eels betwe5 !m4 ,maxwell 9 ! pap] consid]$ ^! roll+ p>ticles to be p>ticles ( electricity4 ,_! motion con/itutes an electric curr5t4 ,9 a uni=m magnetic field !re is no electric curr5t2 if ! /r5g? ( ! field v>ies1 ! idle :eels are set 9 motion & !re may be a curr5t4 ,^! p>ticles are v small comp>$ ) ! magnetic vortices4 ,! mass ( all ! p>ticles is inappreciable comp>$ ) ! mass ( ! vortices1 & a great _m vortices ) _! surr\nd+ p>ticles are conta9$ 9 a molecule ( ! m$ium2 ! p>ticles roll on ! vortices )\t t\*+ ea* o!r1 s t s long z !y rema9 )9 ! same molecule !re is no loss ( en]gy by resi/ance4 ,:51 h[ev]1 !re is a curr5t or g5]al transf]5ce ( p>ticles 9 "o direction !y mu/ pass f "o molecule to ano!r1 & 9 do+ s may exp]i5ce resi/ance & g5]ate heat4 ,maxwell /ates t ! conception ( a p>ticle1 hav+ its motion connect$ ) t ( a vortex by p]fect roll+ contact1 may appe> some:at awkw>d4 8,i d n br+ x =w>d10 he writes1 8z a mode ( connection exi/+ 9 ,nature1 or ev5 z t :i* ,i w\ld will+ly ass5t to z an electrical hypo!sis4 ,x is1 h[ev]1 a mode ( connection :i* is me*anically conceivable & easily inve/igat$1 & x s]ves to br+ out ! actual me*anical connections betwe5 ! kn[n electro-magnetic ph5om5a1 s t ,i v5ture to say t anyone :o und]/&s ! provisional & tempor>y "* ( ?is hypo!sis w f9d himself r help$ ?an h9d]$ by x 9 8 se>* aft] ! true int]pretation ( ! ph5om5a40 ,! fir/ "p ( ! pap] deals ) ! !ory ( magnetism2 9 ! second "p ! hypo!sis is appli$ to ! ph5om5a ( electric curr5ts1 & x is %[n h[ ! kn[n laws ( /eady curr5ts & ( electro-magnetic induction c be d$uc$ f x4 ,9 ,"p ,,iii41 publi%$ ,janu>y & ,febru>y1 #ahfb1 ! !ory ( molecul> vortices is appli$ to /atical electricity4 ,! di/9ction betwe5 a conductor & an insulator or dielectric is suppos$ to be t 9 ! =m] ! p>ticles ( electricity c pass ) m or less fre$om f molecule to molecule4 ,9 ! latt] su* transf]5ce is impossible1 ! p>ticles c only be displac$ )9 ! molecule ) :i* !y are connect$2 ! cells or vortices ( ! m$ium are suppos$ to be ela/ic1 & to resi/ by _! ela/icity ! displacem5t ( ! p>ticles )9 !m4 ,:5 electrical =ce acts on ! m$ium ?is displacem5t ( ! p>ticles )9 ea* molecule takes place until ! /resses due to ! ela/ic reaction ( ! vortices balance ! electrical =ce2 ! m$ium behaves l an ela/ic body yield+ to pressure until ! pressure is balanc$ by ! ela/ic /ress4 ,:5 ! electric =ce is remov$ ! cells or vortices recov] _! =m1 ! electricity returns to its =m] position4 ,9 a m$ium su* z ?is waves ( p]iodic displacem5t c\ld be set up1 & w\ld travel ) a velocity dep5d+ on its electric prop]ties4 ,! value = ?is velocity c be obta9$ f electrical obs]vations1 & ,maxwell %[$ t ?is velocity1 s f\nd1 01 )9 ! limits ( exp]im5tal error1 ! same z t ( light4 ,moreov]1 ! electrical oscillations take place1 l ^? ( light1 9 ! front ( ! wave4 ,h5ce1 he concludes1 8! ela/icity ( ! magnetic m$ium 9 air is ! same z t ( ! lum9if]\s m$ium1 if ^! two coexi/5t1 coext5sive1 & equally ela/ic m$ia are n r "o m$ium40 ,! pap] ?us conta9s ! fir/ g]ms ( ! electro-magnetic !ory ( light4 ,moreov]1 x is %[n t ! attraction betwe5 two small bodies *>g$ ) giv5 quantities ( electricity dep5ds on ! m$ium 9 :i* !y are plac$1 :ile ! specific inductive capacity is f\nd to be proportional to ! squ>e ( ! refractive index4 ,! f\r? & f9al "p ( ! pap] inve/igates ! propagation ( light 9 a magnetic field4 ,f>aday _h %[n t ! direction ( vibration 9 a wave ( pol>is$ light travell+ p>allel to ! l9es ( =ce 9 a magnetic field is rotat$ by its passage ?r\gh ! field4 ,! num]ical laws ( ?is relation _h be5 inve/igat$ by ,v]det1 & ,maxwell %[$ h[ 8 hypo!sis ( molecul> vortices l$ to laws :i* agree 9 ! ma9 ) ^? f\nd by ,v]det4 ,he po9ts out t ! connection betwe5 magnetism & electricity has ! same ma!matical =m z t betwe5 c]ta9 o!r pairs ( ph5om5a1 "o ( :i* has a l9e> & ! o!r a rotatory "*2 &1 fur!r1 t an analogy may be work$ out assum+ ei!r ! l9e> "* = magnetism & ! rotatory "* = electricity1 or ! rev]se4 ,he alludes to ,pr(4 ,*allis' !ory1 accord+ to :i* magnetism is to consi/ 9 curr5ts 9 a fluid ^: directions correspond ) ! l9es ( magnetic =ce1 :ile electric curr5ts are suppos$ to be accompani$ by1 if n dep5d5t ^u1 a rotatory motion ( ! fluid ab\t ! axis ( ! curr5t2 & to ,von ,helmholtz's !ory ( a some:at simil> "*4 ,he !n gives 8 own reasons--agree+ ) ^? ( ,sir ,w4 ,?omson 7,"l ,kelv97--= suppos+ t !re mu/ be a real rotation go+ on 9 a magnetic field 9 ord] to acc\nt = ! rotation ( ! plane ( pol>isation1 &1 accept+ ^! reasons z valid1 he develops ! consequ5ces ( 8 !ory ) ! results /at$ above4 ,8 own v]dict on ! !ory is giv5 9 ! 8,electricity & ,magnetism0 7vol4 ii41 #hca1 fir/ edition1 p4 #daf73-- 8,a !ory ( molecul> vortices1 :i* ,i work$ out at consid]able l5g?1 0 publi%$ 9 ! ,phil4 ,mag4 = ,m>*1 ,april1 & ,may1 #ahfa2 ,jan4 & ,feb41 #ahfb4 8,i ?9k we h good evid5ce = ! op9ion t "s ph5om5on ( rotation is go+ on 9 ! magnetic field1 t ?is rotation is p]=m$ by a great numb] ( v small portions ( matt]1 ea* rotat+ on its own axis1 ?is axis be+ p>allel to ! direction ( ! magnetic =ce1 & t ! rotations ( ^! diff]5t vortices are made to dep5d on "o ano!r by means ( "s k9d ( me*anism connect+ !m4 8,! attempt :i* ,i !n made to imag9e a work+ model ( ?is me*anism mu/ be tak5 = no m ?an x really is1 a demon/ration t me*anism may be imag9$ capable ( produc+ a connection me*anically equival5t to ! actual connection ( ! p>ts ( ! electro-magnetic field4 ,! problem ( det]m9+ ! me*anism requir$ to e/abli% a giv5 species ( connection betwe5 ! motions ( ! p>ts ( a sy/em always admits ( an inf9ite numb] ( solutions4 ,( ^!1 "s may be m clumsy or m complex ?an o!rs1 b all mu/ satisfy ! conditions ( me*anism 9 g5]al4 8,! foll[+ results ( ! !ory1 h[ev]1 are ( high] value3-- 87#a7 ,magnetic =ce is ! effect ( ! c5trifugal =ce ( ! vortices4 87#b7 ,electro-magnetic induction ( curr5ts is ! effect ( ! =ces call$ into play :5 ! velocity ( ! vortices is *ang+4 87#c7 ,electromotive =ce arises f ! /ress on ! connect+ me*anism4 87#d7 ,electric displacem5t arises f ! ela/ic yield+ ( ! connect+ me*anism40 ,9 /udy+ ?is "p ( ,maxwell's "w1 x mu/ cle>ly be rememb]$ t he did n look ^u ! e!r z a s]ies ( cog-:eels ) idle :eels betwe51 or any?+ ( ! k9d4 ,he devis$ a me*anical model ( su* cogs & idle :eels1 ! prop]ties ( :i* w\ld 9 "s respects closely resemble ^? ( ! e!r2 f ?is model he d$uc$1 among o!r ?+s1 ! important fact t electric waves w\ld travel outw>ds ) ! velocity ( light4 ,o!r su* models h be5 devis$ s9ce 8 "t to illu/rate ! same laws4 ,pr(4 ,fitzg]ald has actually con/ruct$ "o ( :eels connect$ toge!r by ela/ic b&s1 :i* %[s cle>ly ! k9d ( processes :i* ,maxwell suppos$ to g on 9 a dielectric :5 "u electric =ce4 ,pr(essor ,lodge1 9 8 book1 8,mod]n ,views ( ,electricity10 has v fully develop$ a some:at diff]5t arrangem5t ( cog-:eels to atta9 ! same result4 ,maxwell's pr$ictions z to ! propagation ( electric waves h 9 rec5t days receiv$ _! full v]ification 9 ! brilliant exp]im5ts ( ,h]tz & 8 foll[]s2 x rema9s = u1 be=e deal+ ) ^!1 to trace _! f9al developm5t 9 8 h&s4 ,! pap]s we h be5 discuss+ 7 p]haps too mat]ial to receive ! full att5tion !y des]v$2 ! e!r is n a s]ies ( cogs1 & electricity is some?+ diff]5t f mat]ial idle :eels4 ,9 8 pap] on 8,! ,dynamical ,!ory ( ! ,electro-magnetic ,field10 ,phil4 ,trans41 #ahfd1 ,maxwell treats ! same que/ions 9 a m g5]al mann]4 ,on a =m] occasion he says1 8,i h attempt$ to describe a p>ticul> k9d ( motion & a p>ticul> k9d ( /ra9 s arrang$ z to acc\nt = ! ph5om5a4 ,9 ! pres5t pap] ,i avoid any hypo!sis ( ?is k9d2 & 9 us+ su* words z electric mom5tum & electric ela/icity 9 ref]5ce to ! kn[n ph5om5a ( ! induction ( curr5ts & ! pol>isation ( dielectrics1 ,i wi% m]ely to direct ! m9d ( ! read] to me*anical ph5om5a1 :i* w assi/ him 9 und]/&+ ! electrical ones4 ,all su* phrases 9 ! pres5t pap] are to be consid]$ z illu/rative & n z explanatory40 ,he !n cont9ues3-- 8,9 speak+ ( ! en]gy ( ! field1 h[ev]1 ,i wi% to be und]/ood lit]ally4 ,all en]gy is ! same z me*anical en]gy1 :e!r x exi/s 9 ! =m ( motion or 9 t ( ela/icity1 or 9 any o!r =m4 8,! en]gy 9 electro-magnetic ph5om5a is me*anical en]gy4 ,! only "q is1 ,:]e does x reside8 8,on ! old !ories x resides 9 ! electrifi$ bodies1 conduct+ circuits1 & magnets1 9 ! =m ( an unkn[n quality call$ pot5tial en]gy1 or ! p[] ( produc+ c]ta9 effects at a di/ance4 ,on our !ory x resides 9 ! electro-magnetic field1 9 ! space surr\nd+ ! electrifi$ & magnetic bodies1 z well z 9 ^? bodies !mselves1 & is 9 two diff]5t =ms1 :i* may be describ$ )\t hypo!sis z magnetic pol>isation & electric pol>isation1 or1 accord+ to a v probable hypo!sis1 z ! motion & ! /ra9 ( "o & ! same m$ium4 8,! conclusions arriv$ at 9 ! pres5t pap] are indep5d5t ( ?is hypo!sis1 be+ d$uc$ f exp]im5tal facts ( ?ree k9ds3-- 87#a7 ,! induction ( electric curr5ts by ! increase or dim9ution ( neighb\r+ curr5ts accord+ to ! *anges 9 ! l9es ( =ce pass+ ?r\gh ! circuit4 87#b7 ,! di/ribution ( magnetic int5sity accord+ to ! v>iations ( a magnetic pot5tial4 87#c7 ,! induction 7or influ5ce7 ( /atical electricity ?r\gh dielectrics4 8,we may n[ proce$ to demon/rate f ^! pr9ciples ! exi/5ce & laws ( ! me*anical =ces1 :i* act ^u electric curr5ts1 magnets1 & electrifi$ bodies plac$ 9 ! electro-magnetic field40 ,9 8 introduction to ! pap]1 he discusses 9 a g5]al way ! v>i\s explanations ( electric ph5om5a :i* _h be5 giv51 & po9ts out t-- 8,x appe>s1 !re=e1 t c]ta9 ph5om5a 9 electricity & magnetism lead to ! same conclusion z ^? ( optics1 namely1 t !re is an !rial m$ium p]vad+ all bodies1 & modifi$ only 9 degree by _! pres5ce2 t ! p>ts ( ?is m$ium are capable ( be+ set 9 motion by electric curr5ts & magnets2 t ?is motion is communicat$ f "o "p ( ! m$ium to ano!r by =ces aris+ f ! connection ( ^? p>ts2 t "u ! action ( ^! =ces !re is a c]ta9 yield+ dep5d+ on ! ela/icity ( ^! connections2 & t1 !re=e1 en]gy 9 two diff]5t =ms may exi/ 9 ! m$ium1 ! "o =m be+ ! actual en]gy ( motion ( its p>ts1 & ! o!r be+ ! pot5tial en]gy /or$ up 9 ! connections 9 virtue ( _! ela/icity4 8,?us1 !n1 we are l$ to ! conception ( a complicat$ me*anism capable ( a va/ v>iety ( motion1 b at ! same "t s connect$ t ! motion ( "o "p dep5ds1 accord+ to def9ite relations1 on ! motion ( o!r p>ts1 ^! motions be+ communicat$ by =ces aris+ f ! relative displacem5t ( ! connect$ p>ts1 9 virtue ( _! ela/icity4 ,su* a me*anism mu/ be subject to ! g5]al laws ( dynamics1 & we ought to be able to "w out all ! consequ5ces ( its motion1 provid$ we "k ! =m ( ! relation betwe5 ! motions ( ! p>ts40 ,^! g5]al laws ( dynamics1 applicable to ! motion ( any connect$ sy/em1 _h be5 develop$ by ,lagrange1 & are express$ 9 8 g5]alis$ equations ( motion4 ,x is "o ( ,maxwell's *ief claims to fame t he saw 9 ! electric field a connect$ sy/em to :i* ,lagrange's equations c\ld be appli$1 & t he 0 able to d$uce ! me*anical & electrical actions :i* take place by means ( fundam5tal propositions ( dynamics4 ,! me?ods ( ! pap] n[ "u discussion 7 develop$ fur!r 9 ! 8,treatise on ,electricity & ,magnetism10 publi%$ 9 #ahgc2 9 endeav\r+ to give "s slight acc\nt ( ,maxwell's "w1 we %all describe x 9 ! =m x ultimately took4 ,! task :i* ,maxwell set himself 0 a d\ble "o2 he _h fir/ to express 9 symbols1 9 z g5]al a =m z possible1 ! fundam5tal laws ( electro-magnetism z d$uc$ f exp]im5ts1 *iefly ! exp]im5ts ( ,f>aday1 & ! relations betwe5 ! v>i\s quantities involv$2 :5 ?is 0 done he _h to %[ h[ ^! laws c\ld be d$uc$ f ! g5]al dynamical laws applicable to any sy/em ( mov+ bodies4 ,!re are two classes ( ph5om5a1 electric & magnetic1 :i* h be5 kn[n f v e>ly times1 & :i* are connect$ toge!r4 ,:5 a piece ( seal+-wax is rubb$ x is f\nd to attract o!r bodies1 x is said to ex]t electric =ce ?r\gh\t ! space surr\nd+ x2 :5 two diff]5t metals are dipp$ 9 slightly acidulat$ wat] & connect$ by a wire1 c]ta9 *anges take place 9 ! plates1 ! wat]1 ! wire1 & ! space r\nd ! wire1 electric =ce is aga9 ex]t$ & a curr5t ( electricity is said to fl[ 9 ! wire4 ,aga91 c]ta9 bodies1 su* z ! lode/one1 or pieces ( iron & /eel :i* h be5 treat$ 9 a c]ta9 mann]1 exhibit ph5om5a ( action at a di/ance3 !y are said to ex]t magnetic =ce1 & x is f\nd t ?is magnetic =ce exi/s 9 ! neighb\rhood ( an electric curr5t & is connect$ ) ! curr5t4 ,aga91 :5 electric =ce is appli$ to a body1 ! effects may be 9 "p electrical1 9 "p me*anical2 ! electrical /ate ( ! body is 9 g5]al *ang$1 :ile 9 addition1 me*anical =ces t5d+ to move ! body are set up4 ,exp]im5t mu/ tea* u h[ ! electrical /ate dep5ds on ! electric =ce1 & :at is ! connection betwe5 ?is electric =ce & ! magnetic =ces :i* may1 "u c]ta9 circum/ances1 be obs]v$4 ,n[1 9 specify+ ! electric & magnetic conditions ( ! sy/em1 v>i\s o!r quantities1 9 addition to ! electric =ce1 w h to be introduc$2 ! fir/ /ep is to =mulate ! necess>y quantities1 & to det]m9e ! relations betwe5 !m & ! electric =ce4 ,consid] n[ a wire connect+ ! two poles ( an electric batt]y--9 its simple/ =m1 a piece ( z9c & a piece ( copp] 9 a vessel ( dilute acid--electric =ce is produc$ at ea* po9t ( ! wire4 ,let u suppose ?is =ce kn[n2 an electric curr5t dep5d+ on ! mat]ial & ! size ( ! wire fl[s along x1 its value c be det]m9$ at ea* po9t ( ! wire 9 t]ms ( ! electric =ce by ,ohm's law4 ,if we take ei!r ?is curr5t or ! electric =ce z kn[n1 we c det]m9e by kn[n laws ! electric & magnetic conditions else:]e4 ,if we suppose ! wire to be /raight & v long1 !n1 s long z ! curr5t is /eady & we neglect ! small effect due to ! electro/atic *>ge on ! wire1 !re is no electric =ce outside ! wire4 ,!re is1 h[ev]1 magnetic =ce1 & x is f\nd t ! l9es ( magnetic =ce are circles r\nd ! wire4 ,x is f\nd also t ! "w done 9 travell+ once completely r\nd ! wire aga9/ ! magnetic =ce is measur$ by ! curr5t fl[+ ?r\gh ! wire1 & is obta9$ 9 ! sy/em ( units usually adopt$ by multiply+ ! curr5t by #d4 ,?is la/ result !n gives u "o ( ! necess>y relations1 t betwe5 ! magnetic =ce due to a curr5t & ! /r5g? ( ! curr5t4 ,aga91 consid] a /eady curr5t fl[+ 9 a conductor ( any =m or %ape1 ! total fl[ ( curr5t across any section ( ! conductor c be measur$ 9 v>i\s ways1 & x is f\nd t at any "t ?is total fl[ is ! same = ea* section ( ! conductor4 ,9 ?is respect ! fl[ ( a curr5t resembles t ( an incompressible fluid ?r\gh a pipe2 :]e ! pipe is n>r[ ! velocity ( fl[ is great] ?an x is :]e ! pipe is broad1 b ! total quantity cross+ ea* section at any giv5 in/ant is ! same4 ,consid] n[ two conduct+ bodies1 two sph]es1 or two flat plates plac$ ne> toge!r b insulat$4 ,let ea* conductor be connect$ to "o ( ! poles ( ! batt]y by a conduct+ wire4 ,!n1 = a v %ort int]val aft] ! contact is made1 x is f\nd t !re is a curr5t 9 ea* wire :i* rapidly dies away to z]o4 ,9 ! neighb\rhood ( ! balls !re is electric =ce2 ! balls are said to be *>g$ ) electricity1 & ! l9es ( =ce are curv$ l9es runn+ f "o ball to ! o!r4 ,x is f\nd t ! balls slightly attract ea* o!r1 & ! space betwe5 !m is n[ 9 a diff]5t condition f :at x 0 be=e ! balls 7 *>g$4 ,accord+ to ,maxwell1 ,electric ,displacem5t has be5 produc$ 9 ?is space1 & ! electric displacem5t at ea* po9t is proportional to ! electric =ce at t po9t4 ,?us1 7i7 :5 electric =ce acts on a conductor1 x produces a curr5t1 ! curr5t be+ by ,ohm's law proportional to ! =ce3 7ii7 :5 x acts on an insulator x produces electric displacem5t1 & ! displacem5t is proportional to ! =ce2 :ile 7iii7 !re is magnetic =ce 9 ! neighb\rhood ( ! curr5t1 & ! "w done 9 c>ry+ a magnetic pole r\nd any complete circuit l9k$ ) ! curr5t is proportional to ! curr5t4 ,! fir/ two ( ^! pr9ciples give u two sets ( equations connect+ toge!r ! electric =ce & ! curr5t 9 a conductor or ! displacem5t 9 a dielectric respectively2 ! ?ird connects ! magnetic =ce & ! curr5t4 ,n[ let u g back to ! v>iable p]iod :5 ! curr5t is fl[+ 9 ! wires2 & to make ideas precise1 let ! two conductors be two equal l>ge flat plates plac$ ) _! faces p>allel1 & at "s small di/ance ap>t4 ,9 ?is case1 :5 ! plates are *>g$1 & ! curr5t has ceas$1 ! electric displacem5t & ! =ce are conf9$ almo/ entirely to ! space betwe5 ! plates4 ,dur+ ! v>iable p]iod ! total fl[ at any in/ant across ea* section ( ! wire is ! same1 b 9 ! ord9>y s5se ( ! ^w !re is no fl[ ( electricity across ! insulat+ m$ium betwe5 ! plates4 ,9 ?is space1 h[ev]1 ! electric displacem5t is cont9u\sly *ang+1 ris+ f z]o initially to its f9al /eady value :5 ! curr5t ceases4 ,x is a fundam5tal "p ( ,maxwell's !ory t ?is v>iation ( electric displacem5t is equival5t 9 all respects to a curr5t4 ,! curr5t at any po9t 9 a dielectric is measur$ by ! rate ( *ange ( displacem5t at t po9t4 ,moreov]1 x is also an ess5tial po9t t if we consid] any section ( ! dielectric betwe5 ! two plates1 ! rate ( *ange ( ! total displacem5t across ?is section is at ea* mom5t equal to ! total fl[ ( curr5t across ea* section ( ! conduct+ wire4 ,curr5ts ( electricity1 !re=e1 includ+ displacem5t curr5ts1 always fl[ 9 clos$ circuits1 & obey ! laws ( an incompressible fluid 9 t ! total fl[ across ea* section ( ! circuit--conduct+ or dielectric--is at any mom5t ! same4 ,x %\ld be cle>ly rememb]$ t ?is fundam5tal hypo!sis ( ,maxwell's !ory is an assumption only to be ju/ifi$ by exp]im5t4 ,von ,helmholtz1 9 8 pap] on 8,! ,equations ( ,motion ( ,electricity = ,bodies at ,re/10 =m$ 8 equations 9 an entirely diff]5t mann] f ,maxwell1 & arriv$ at results ( a m g5]al "*1 :i* d n require u to suppose t curr5ts fl[ always 9 clos$ circuits1 b p]mit ( ! cond5sation ( electricity at po9ts 9 ! circuit :]e ! conductors end & ! non-conduct+ "p ( ! circuit beg9s4 ,we leave = ! pres5t ! "q :i* ( ! two !ories1 if ei!r1 repres5ts ! facts4 ,we h obta9$ above ?ree fundam5tal relations--7i7 t betwe5 electric =ce & electric curr5t 9 a conductor2 7ii7 t betwe5 electric =ce & electric displacem5t 9 a dielectric2 7iii7 t betwe5 magnetic =ce & ! curr5t :i* gives rise to x4 ,& we h se5 t an electric curr5t--i4e4 9 a dielectric ! v>iation ( ! /r5g? ( an electric field ( =ce--gives rise to magnetic =ce4 ,n[1 magnetic =ce act+ on a m$ium produces 8magnetic displacem5t10 or magnetic induction1 z x is call$4 ,9 all m$ia except iron1 nickel1 cobalt1 & a few o!r sub/ances1 ! magnetic induction is proportional to ! magnetic =ce1 & ! ratio betwe5 ! magnetic induction produc$ by a giv5 =ce & ! =ce is f\nd to be v ne>ly ! same = all su* m$ia4 ,?is ratio is kn[n z ! p]meability1 & is g5]ally d5ot$ by ! symbol 4 ,a relation reciprocal to t giv5 9 7iii7 above might be anticipat$1 & 01 9 fact1 discov]$ by ,f>aday4 ,*anges 9 a field ( magnetic induction give rise to electric =ce1 & h5ce to displacem5t curr5ts 9 a dielectric or to conduction curr5ts 9 a conductor4 ,9 consid]+ ! relation betwe5 ^! *anges & ! electric =ce1 x is simple/ at fir/ n to deal ) magnetic matt] su* z iron1 nickel1 or cobalt2 & !n we may say t 7iv7 ! "w :i* at any in/ant w\ld be done 9 c>ry+ a unit quantity ( electricity r\nd a clos$ circuit 9 a magnetic field aga9/ ! electric =ces due to ! field is equal to ! rate at :i* ! total magnetic induction :i* ?reads ! circuit is be+ decreas$4 ,?is law1 summ+ up ,f>aday's exp]im5ts on electro-magnetic induction1 gives a f\r? pr9ciple1 lead+ to a f\r? s]ies ( equations connect+ toge!r ! electric & magnetic quantities involv$4 ,! equations d$uc$ f ! above f\r pr9ciples1 toge!r ) ! condition impli$ 9 ! cont9uity ( an electric curr5t1 con/itute ,maxwell's equations ( ! electro-magnetic field4 ,if we are deal+ only ) a dielectric m$ium1 ! reciprocal relation betwe5 ! ?ird & f\r? pr9ciple may be made m cle> by ! foll[+ /atem5t3-- 7,a7 ,! "w done at any mom5t 9 c>ry+ a unit quantity ( magnetism r\nd a clos$ circuit 9 a field 9 :i* electric displacem5t is v>y+1 is equal to ! rate ( *ange ( ! total electric displacem5t ?r\gh ! circuit multipli$ by #d 4#fb 7,b7 ,! "w done at any mom5t 9 c>ry+ a unit quantity ( electricity r\nd a circuit 9 a field 9 :i* ! magnetic induction is v>y+1 is equal to ! rate ( *ange ( ! total magnetic induction ?r\gh ! circuit4 ,f ^! two pr9ciples1 comb9$ ) ! laws connect+ electric =ce & displacem5t1 magnetic =ce & induction1 & ) ! condition ( cont9uity1 ,maxwell obta9$ 8 equations ( ! field4 ,f>aday's exp]im5ts on electro-magnetic induction af=d ! pro( ( ! tru? ( ! f\r? pr9ciple4 ,x foll[s f ^? exp]im5ts t :5 ! numb] ( l9es ( magnetic induction :i* are l9k$ ) any clos$ circuit are made to v>y1 an induc$ electromotive =ce is br\ght into play r\nd t circuit4 ,?is electromotive =ce is1 accord+ to ,f>aday's results1 measur$ by ! rate ( decrease 9 ! numb] ( l9es ( magnetic induction :i* ?read ! circuit4 ,maxwell applies ?is pr9ciple to all circuits1 :e!r conduct+ or n4 ,9 obta9+ equations to express 9 symbols ! results ( ! f\r? pr9ciple j enunciat$1 ,maxwell introduces a new quantity1 to :i* he gives ! "n ( ! 8vector pot5tial40 ,?is quantity appe>s 9 8 analysis1 & its physical mean+ is n at fir/ q cle>4 ,pr(essor ,poynt+ has1 h[ev]1 put ,maxwell's pr9ciples 9 a slightly diff]5t =m1 :i* enables u to see def9itely ! mean+ ( ! vector pot5tial1 & to d$uce ,maxwell's equations m readily f ! fundam5tal /atem5ts4 ,we are deal+ ) a circuit ) :i* l9es ( magnetic induction are l9k$1 :ile ! numb] ( su* l9es l9k$ ) ! circuit is v>y+4 ,n[1 let u suppose ! v>iation to take place 9 consequ5ce ( ! l9es ( induction mov+ outw>ds or inw>ds1 z ! case may be1 s z to cut ! circuit4 ,orig9ally !re are none l9k$ ) ! circuit4 ,z ! magnetic field has gr[n to its pres5t /r5g? l9es ( magnetic induction h mov$ inw>ds4 ,ea* little elem5t ( ! circuit has be5 cut by "s1 & ! total numb] l9k$ ) ! circuit c be f\nd by add+ toge!r ^? cut by ea* elem5t4 ,n[1 ,pr(essor ,poynt+'s /atem5t ( ,maxwell's f\r? pr9ciple is t ! electrical =ce 9 ! direction ( any elem5t ( ! circuit is f\nd by divid+ by ! l5g? ( ! elem5t ! numb] ( l9es ( magnetic induction :i* are cut 9 "o second by x4 ,moreov]1 ! total numb] ( l9es ( magnetic induction :i* h be5 cut by an elem5t ( unit l5g? is def9$ z ! compon5t ( ! vector pot5tial 9 ! direction ( ! elem5t2 h5ce ! electrical =ce 9 any direction is ! rate ( decrease ( ! compon5t ( ! vector pot5tial 9 t direction4 ,we h ?us a physical mean+ = ! vector pot5tial1 & %all f9d t 9 ! dynamical !ory ?is quantity is ( great importance4 ,pr(essor ,poynt+ has modifi$ ,maxwell's ?ird pr9ciple 9 a simil> mann]2 he looks ^u ! v>iation 9 ! electric displacem5t z due to ! motion ( tubes ( electric induction1#fc & ! magnetic =ce along any circuit is equal to ! numb] ( tubes ( electric induction cutt+ or cut by unit l5g? ( ! circuit p] second1 multipli$ by #d4 ,f ! equations ( ! field1 z f\nd by ,maxwell1 x is possible to d]ive two sets ( symmetrical equations4 ,! "o set connects ! rate ( *ange ( ! electric =ce ) quantities dep5d+ on ! magnetic =ce2 ! o!r set connects 9 a simil> mann] ! rate ( *ange ( ! magnetic =ce ) quantities dep5d+ on ! electric =ce4 ,sev]al writ]s 9 rec5t ye>s adopt ^! equations z ! fundam5tal relations ( ! field1 e/abli%+ !m by ! argum5t t !y lead to consequ5ces :i* are f\nd to be 9 accordance ) exp]im5t4 ,we h endeav\r$ to give "s acc\nt ( ,maxwell's hi/orical me?od1 accord+ to :i* ! equations are d$uc$ f ! laws ( electric curr5ts & ( electro-magnetic induction d]iv$ directly f exp]im5t4 ,:ile ! mann] 9 :i* ,maxwell obta9$ 8 equations is all 8 own1 he 0 n alone 9 /at+ & discuss+ g5]al equations ( ! electro-magnetic field4 ,! next /eps :i* we are ab\t to consid] are1 h[ev]1 9 a special mann] due to him4 ,an electrical or magnetic sy/em is ! seat ( en]gy2 ?is en]gy is p>tly electrical1 p>tly magnetic1 & v>i\s expressions c be f\nd = x4 ,9 ,maxwell's !ory x is a fundam5tal assumption t en]gy has position4 8,! electric & magnetic en]gies ( any electro-magnetic sy/em10 says ,pr(essor ,poynt+1 8reside1 !re=e1 some:]e 9 ! field40 ,x foll[s f ?is t !y are pres5t :]ev] electric & magnetic =ce c be %[n to exi/4 ,maxwell %[$ t all ! electric en]gy is acc\nt$ = by suppos+ t 9 ! neighb\rhood ( a po9t at :i* ! electric =ce is ,r !re is an am\nt ( en]gy p] unit ( volume equal to ,,kr_/#h1 ,k be+ ! inductive capacity ( ! m$ium1 :ile 9 ! neighb\rhood ( a po9t at :i* ! magnetic =ce is ,h1 ! magnetic en]gy p] unit ( volume is ,h_/#h1 be+ ! p]meability4 ,he supposes1 !n1 t at ea* po9t ( an electro-magnetic sy/em en]gy is /or$ accord+ to ^! laws4 ,x foll[s1 !n1 t ! electro-magnetic field resembles a dynamical sy/em 9 :i* en]gy is /or$4 ,c we discov] m ( ! me*anism by :i* ! actions 9 ! field are ma9ta9$8 ,n[ ! motion ( any po9t ( a connect$ sy/em dep5ds on t ( o!r po9ts ( ! sy/em2 !re are g5]ally1 9 any ma*9e1 a c]ta9 numb] ( po9ts call$ driv+-po9ts1 ! motion ( :i* controls ! motion ( all o!r p>ts ( ! ma*9e2 if ! motion ( ! driv+-po9ts be kn[n1 t ( any o!r po9t c be det]m9$4 ,?us 9 a /eam eng9e ! motion ( a po9t on ! fly-:eel c be f\nd if ! motion ( ! pi/on & ! connections betwe5 ! pi/on & ! :eel be kn[n4 ,9 ord] to det]m9e ! =ce :i* is act+ on any "p ( ! ma*9e we mu/ f9d its mom5tum1 & !n calculate ! rate at :i* ?is mom5tum is be+ *ang$4 ,?is rate ( *ange w give u ! =ce4 ,! me?od ( calculation :i* x is necess>y to employ 0 fir/ giv5 by ,lagrange1 & aft]w>ds develop$1 ) "s modifications1 by ,hamilton4 ,x is usually ref]r$ to z ,hamilton's pr9ciple2 :5 ! equations 9 ! orig9al =m are us$ !y are kn[n z ,lagrange's equations4 ,n[ ,maxwell %[$ h[ ^! me?ods ( calculation c\ld be appli$ to ! electro-magnetic field4 ,! en]gy ( a dynamical sy/em is p>tly k9etic1 p>tly pot5tial4 ,maxwell supposes t ! magnetic en]gy ( ! field is k9etic en]gy1 ! electric en]gy pot5tial4 ,:5 ! k9etic en]gy ( a sy/em is kn[n1 ! mom5tum ( any "p ( ! sy/em c be calculat$ by recognis$ processes4 ,?us if we consid] a circuit 9 an electro-magnetic field we c calculate ! en]gy ( ! field1 & h5ce obta9 ! mom5tum correspond+ to ?is circuit4 ,if we deal ) a simple case 9 :i* ! conduct+ circuits are fix$ 9 position1 & only ! curr5t 9 ea* circuit is all[$ to v>y1 ! rate ( *ange ( mom5tum correspond+ to any circuit w give ! =ce 9 t circuit4 ,! mom5tum 9 "q is electric mom5tum1 & ! =ce is electric =ce4 ,n[ we h already se5 t ! electric =ce at any po9t ( a conduct+ circuit is giv5 by ! rate ( *ange ( ! vector pot5tial 9 ! direction consid]$4 ,h5ce we are l$ to id5tify ! vector pot5tial ) ! electric mom5tum ( our dynamical sy/em2 &1 ref]r+ to ! orig9al def9ition ( vector pot5tial1 we see t ! electric mom5tum ( a circuit is measur$ by ! numb] ( l9es ( magnetic induction :i* are int]l9k$ ) x4 ,aga91 ! k9etic en]gy ( a dynamical sy/em c be express$ 9 t]ms ( ! squ>es & products ( ! velocities ( its sev]al p>ts4 ,x c also be express$ by multiply+ ! velocity ( ea* driv+-po9t by ! mom5tum correspond+ to t driv+-po9t1 & tak+ half ! sum ( ! products4 ,suppose1 n[1 we are deal+ ) a sy/em consi/+ ( a numb] ( wire circuits 9 :i* curr5ts are runn+1 & let u suppose t we may repres5t ! curr5t 9 ea* wire z ! velocity ( a driv+-po9t 9 our dynamical sy/em4 ,we c also express 9 t]ms ( ^! curr5ts ! electric mom5tum ( ea* wire circuit2 let ?is be done1 & let half ! sum ( ! products ( ! correspond+ velocities & mom5ta be =m$4 ,9 ma9ta9+ ! curr5ts 9 ! wires en]gy is ne$$ to supply ! heat :i* is produc$ 9 ea* wire2 b 9 />t+ ! curr5ts x is f\nd t m en]gy is ne$$ ?an is requisite = ! supply ( ?is heat4 ,?is excess ( en]gy c be calculat$1 & :5 ! calculation is made x is f\nd t ! excess is equal to half ! sum ( ! products ( ! curr5ts & correspond+ mom5ta4 ,moreov]1 if ?is sum be express$ 9 t]ms ( ! magnetic =ce1 x is f\nd to be equal to ,h_/#h 1 :i* is ! magnetic en]gy ( ! field4 ,n[1 :5 a dynamical sy/em is set 9 motion aga9/ kn[n =ces1 m en]gy is suppli$ ?an is ne$$ to d ! "w aga9/ ! =ces2 ?is excess ( en]gy measures ! k9etic en]gy acquir$ by ! sy/em4 ,h5ce1 ,maxwell 0 ju/ifi$ 9 tak+ ! magnetic en]gy ( ! field z ! k9etic en]gy ( ! me*anical sy/em1 & if ! /r5g?s ( ! curr5ts 9 ! wires be tak5 to repres5t ! velocities ( ! driv+-po9ts1 ?is en]gy is measur$ 9 t]ms ( ! electrical velocities & mom5ta 9 exactly ! same way z ! en]gy ( a me*anical sy/em is measur$ 9 t]ms ( ! velocities & mom5ta ( its driv+-po9ts4 ,! me*anical sy/em 9 :i*1 accord+ to ,maxwell1 ! en]gy is /or$ is ! e!r4 ,a /ate ( motion or ( /ra9 is set up 9 ! e!r ( ! field4 ,! electric =ces :i* drive ! curr5ts1 & also ! me*anical =ces act+ on ! conductors c>ry+ ! curr5ts1 are due to ?is /ate ( motion1 or x may be ( /ra91 9 ! e!r4 ,x mu/ n be suppos$ t ! t]m electric displacem5t 9 ,maxwell's m9d meant an actual bodily displacem5t ( ! p>ticles ( ! e!r2 x is 9 "s way connect$ ) su* a mat]ial displacem5t4 ,9 8 view1 )\t motion ( ! e!r p>ticles !re w\ld be no electric action1 b he does n id5tify electric displacem5t & ! displacem5t ( an e!r p>ticle4 ,8 me*anical !ory1 h[ev]1 does acc\nt = ! electro-magnetic =ces betwe5 conductors c>ry+ curr5ts4 ,! en]gy ( ! sy/em dep5ds on ! relative positions ( ! curr5ts :i* =m "p ( x4 ,n[1 any cons]vative me*anical sy/em t5ds to set itself 9 su* a position t its pot5tial en]gy is lea/1 its k9etic en]gy greate/4 ,! circuits ( ! sy/em1 !n1 w t5d to set !mselves s t ! electro-k9etic en]gy ( ! sy/em may be z l>ge z possible2 =ces w be ne$$ to hold !m 9 any position 9 :i* ?is condition is n satisfi$4 ,we h ano!r pro( ( ! correctness ( ! value f\nd = ! en]gy ( ! field 9 t ! =ces calculat$ f ?is value agree ) ^? :i* are det]m9$ by direct exp]im5t4 ,aga91 ! =ces appli$ at ! v>i\s driv+-po9ts are transmitt$ to o!r po9ts by ! connections ( ! ma*9e2 ! connections are ?r[n into a /ate ( /ra92 /ress exi/s ?r\gh\t _! sub/ance4 ,:5 we see ! pi/on-rod & ! %aft ( an eng9e connect$ by ! crank & ! connect+-rod1 we recognise t ! "w done on ! pi/on is transmitt$ ?us to ! %aft4 ,s1 too1 9 ! electro-magnetic field1 ! e!r =ms ! connection betwe5 ! v>i\s circuits 9 ! field2 ! =ces ) :i* ^? circuits act on ea* o!r are transmitt$ f "o circuit to ano!r by ! /resses set up 9 ! e!r4 ,to take ano!r in/ance1 consid] ! electro/atic attraction betwe5 two *>g$ bodies4 ,let u suppose ! bodies *>g$ by connect+ ea* to ! opposite pole ( a batt]y2 a curr5t fl[s f ! batt]y sett+ up electric displacem5t 9 ! space betwe5 ! bodies1 & ?r[+ ! e!r into a /ate ( /ra94 ,z ! /ra9 increases ! curr5t gets less2 ! reaction result+ f ! /ra9 t5ds to /op x1 until at la/ ?is reaction is s great t ! curr5t is /opp$4 ,:5 ?is is ! case ! wires to ! batt]y may be remov$1 provid$ ?is is done )\t de/roy+ ! insulation ( ! bodies2 ! /ate ( /ra9 w rema9 & %[s itself 9 ! attraction betwe5 ! balls4 ,look+ at ! problem 9 ?is mann]1 we are face to face ) two great que/ions--! "o1 ,:at is ! /ate ( /ra9 9 ! e!r :i* w enable x to produce ! obs]v$ electro/atic attractions & repulsions betwe5 *>g$ bodies8 & ! o!r1 ,:at is ! me*anical /ructure ( ! e!r :i* w\ld give rise to su* a /ate ( /ra9 z w acc\nt = ! obs]v$ =ces8 ,maxwell gives "o answ] to ! fir/ "q2 x is n ! only answ] :i* c\ld be giv51 b x does acc\nt = ! facts4 ,he fail$ to answ] ! second4 ,he says 78,electricity & ,magnetism10 vol4 i4 p4 #acb73-- 8,x mu/ be c>efully borne 9 m9d t we h made only "o /ep 9 ! !ory ( ! action ( ! m$ium4 ,we h suppos$ x to be 9 a /ate ( /ress1 b h n 9 any way acc\nt$ = ?is /ress1 or expla9$ h[ x is ma9ta9$4444 ,i h n be5 able to make ! next /ep1 namely1 to acc\nt by me*anical consid]ations = ^! /resses 9 ! dielectric40 ,f>aday _h po9t$ out t ! inductive action betwe5 two bodies takes place along ! l9es ( =ce1 :i* t5d to %ort5 along _! l5g? & to spread outw>ds 9 o!r directions4 ,maxwell comp>es !m to ! fibres ( a muscle1 :i* contracts & at ! same "t ?ick5s :5 ex]t+ =ce4 ,9 ! electric field !re is1 on ,maxwell's !ory1 a t5sion along ! l9es ( electric =ce & a pressure at "r angles to ^? l9es4 ,maxwell prov$ t a t5sion ,k ,r_/#h along ! l9es ( =ce1 comb9$ ) an equal pressure 9 p]p5dicul> directions1 w\ld ma9ta9 ! equilibrium ( ! field1 & w\ld give rise to ! obs]v$ attractions or repulsions betwe5 electrifi$ bodies4 ,o!r di/ributions ( /ress might be f\nd :i* w\ld lead to ! same result4 ,! "o j /at$ w always be connect$ ) ,maxwell's "n4 ,x w be notic$ t ! t5sion along ! l9es ( =ce & ! pressure at "r angles to !m are ea* num]ically equal to ! pot5tial en]gy /or$ p] unit ( volume 9 ! field4 ,! value ( ea* ( ! ?ree quantities is ,k ,r_/#h 4 ,9 ! same way1 9 a magnetic field1 !re is a /ate ( /ress1 & on ,maxwell's !ory ?is1 too1 consi/s ( a t5sion along ! l9es ( =ce & an equal pressure at "r angles to !m1 ! values ( ! t5sion & ! pressure be+ ea* equal to t ( ! magnetic en]gy p] unit ( volume1 or ,h_/#h4 ,9 a case 9 :i* bo? electric & magnetic =ce exi/s1 ^! two /ates ( /ress are sup]pos$4 ,! total en]gy p] unit ( volume is ,,kr_/#h ,h_/#h2 ! total /ress is made up ( t5sions ,,kr_/#h & ,h_/#h along ! l9es ( electric & magnetic =ce respectively1 & equal pressures at "r angles to ^! l9es4 ,we see1 !n1 f ,maxwell's !ory1 t electric =ce produc$ at any giv5 po9t 9 space is transmitt$ f t po9t by ! action ( ! e!r4 ,! "q sugge/s itself1 ,does ! transmission take "t1 & if s1 does x proce$ ) a def9ite velocity dep5d+ on ! nature ( ! m$ium ?r\gh :i* ! *ange is proce$+8 ,accord+ to ! molecul>-vortex !ory1 we h se5 t waves ( electric =ce are transmitt$ ) a def9ite velocity4 ,! m g5]al !ory develop$ 9 ! 8,electricity & ,magnetism0 leads to ! same result4 ,electric =ce produc$ at any po9t travels outw>ds f t po9t ) a velocity giv5 by #a_/7,k74 ,at a di/ant po9t ! =ce is z]o1 until ! di/urbance rea*es x4 ,if ! di/urbance la/ only = a limit$ int]val1 its effects w at any future "t be conf9$ to ! space )9 a sph]ical %ell ( con/ant ?ickness dep5d+ on ! int]val2 ! radii ( ?is %ell increase ) uni=m spe$ #a_/7,k74 ,if ! initial di/urbance be p]iodic1 p]iodic waves ( electric =ce w travel out f ! c5tre1 j z waves ( s\nd travel out f a bell1 or waves ( light f a c&le flame4 ,a wire c>ry+ an alt]nat+ curr5t may be su* a s\rce ( p]iodic di/urbance1 & f ! wire waves travel outw>ds into space4 ,n[1 x is kn[n t 9 a s\nd wave ! displacem5ts ( ! air p>ticles take place 9 ! direction 9 :i* ! wave is travell+2 !y lie at "r angles to ! wave front1 & are spok5 ( z longitud9al4 ,9 light waves1 on ! o!r h&1 ! displacem5ts are1 z ,fresnel prov$1 9 ! wave front1 at "r angles1 t is1 to ! direction ( propagation2 !y are transv]se4 ,!ory %[s t 9 g5]al bo? ^! waves may exi/ 9 an ela/ic solid body1 & t !y travel ) diff]5t velocities4 ,( :i* nature are ! waves ( electric displacem5t 9 a dielectric8 ,x c be %ewn to foll[ z a necess>y consequ5ce ( ,maxwell's views z to ! clos$ "* ( all electric curr5ts1 t waves ( electric displacem5t are transv]se4 ,electric vibrations1 l ^? ( light1 are 9 ! wave front & at "r angles to ! direction ( propagation2 !y dep5d on ! rigidity or quasi-rigidity ( ! m$ium ?r\gh :i* !y travel1 n on its resi/ance to compression4 ,aga91 an electric curr5t1 :e!r due to v>iation ( displacem5t 9 a dielectric or to conduction 9 a conductor1 is accompani$ by magnetic =ce4 ,a wave ( p]iodic electric displacem5t1 !n1 w be also a wave ( p]iodic magnetic =ce travell+ at ! same rate2 & ,maxwell %ew$ t ! direction ( ?is magnetic =ce also lies 9 ! wave front1 & is always at "r angles to ! electric displacem5t4 ,9 ! ord9>y !ory ( light ! wave ( l9e> displacem5t is accompani$ by a wave ( p]iodic angul> twi/ ab\t a direction ly+ 9 ! wave front & p]p5dicul> to ! l9e> displacem5t4 ,9 _m respects1 !n1 waves ( electric displacem5t resemble waves ( light1 &1 inde$1 z we proce$ we %all f9d clos] connections /ill4 ,h5ce comes ,maxwell's electro-magnetic !ory ( light4 ,x is only 9 dielectric m$ia t electric =ce is propagat$ by wave motion4 ,9 conductors1 al?\gh ! ?ird & f\r? ( ,maxwell's pr9ciples giv5 on page #ahe /ill are true1 ! relation betwe5 ! electric =ce & ! electric curr5t diff]s f t :i* holds 9 a dielectric4 ,h5ce ! equations satisfi$ by ! =ce are diff]5t4 ,! laws ( its propagation resemble ^? ( ! conduction ( heat r ?an ^? ( ! transmission ( light4 ,aga91 light travels ) diff]5t velocities 9 diff]5t transp>5t m$ia4 ,! velocity ( electric waves1 z has be5 /at$1 is equal to #a_/7,k72 b 9 mak+ ?is /atem5t x is assum$ t ! simple laws :i* hold :]e !re is no gross matt]--or1 r1 :]e air is ! only dielectric ) :i* we are conc]n$--hold also 9 solid or liquid dielectrics4 ,9 a solid or a liquid1 z 9 vacuo1 ! waves are propagat$ by ! e!r4 ,we assume1 z a fir/ /ep t[>ds a complete !ory1 t s f> z ! electric waves are conc]n$ ! sole effect produc$ by ! matt] %ews itself 9 a *ange ( inductive capacity or ( p]meability4 ,x is n likely t su* a supposition %\ld be ! :ole tru?1 & we may1 !re=e1 expect results d$uc$ f x to be only approximation to ! true result4 ,n[1 electro-magnetic exp]im5ts %[ t1 exclud+ magnetic sub/ances1 ! p]meability ( all bodies is v ne>ly ! same1 & diff]s v slightly f t ( air4 ,! inductive capacity1 h[ev]1 ( diff]5t bodies is diff]5t1 & h5ce ! velocity ) :i* electro-magnetic waves travel diff]s 9 diff]5t bodies4 ,b ! refraction ( waves ( light dep5ds on ! fact t light travels ) diff]5t velocities 9 diff]5t m$ia2 h5ce we %\ld expect to h waves ( electric displacem5t reflect$ & refract$ :5 !y pass f "o dielectric1 su* z air1 to ano!r1 su* z glass or gutta-p]*a2 moreov]1 = light ! refractive index ( a m$ium su* z glass is ! ratio ( ! velocity 9 air to ! velocity 9 ! glass4 ,?us ! electrical refractive index ( glass is ! ratio ( ! velocity ( electric waves 9 air to _! velocity 9 glass4 ,n[ let ,k be ! inductive capacity ( air1 ,k t ( glass1 tak+ ! p]meability ( air & glass to be ! same1 we h ! result t-- ,electrical refractive index 7,k_/,k74 ,b ! ratio ( ! inductive capacity ( glass to t ( air is kn[n z ! specific inductive capacity ( glass4 ,h5ce1 ! specific inductive capacity ( any m$ium is equal to ! squ>e ( ! electrical refractive index ( t m$ium4 ,s9ce ,maxwell's "t ! ma!matical laws ( ! reflexion & refraction ( electric waves h be5 inve/igat$ by v>i\s writ]s1 & x has be5 %ewn t !y agree exactly ) ^? enunciat$ by ,fresnel = light4 ,hi!rto we h be5 discuss+ ! propagation ( electric waves 9 an isotropic m$ium1 "o :i* has id5tical prop]ties 9 all directions ab\t a po9t4 ,let u n[ consid] h[ ^! laws are modifi$ if ! dielectric be cry/all9e 9 /ructure4 ,maxwell assumes t ! cry/all9e "* ( ! dielectric c be suffici5tly repres5t$ by suppos+ ! inductive capacity to be diff]5t 9 diff]5t directions2 exp]im5ts h s9ce %ewn t ?is is true = cry/als su* z ,icel& ,sp> & ,aragonite2 he assumes also1 & ?is1 too1 is ju/ifi$ by exp]im5t1 t ! magnetic p]meability does n dep5d on ! direction4 ,x foll[s f ^! assumptions t a cry/al w produce d\ble refraction & pol>isation ( electric waves :i* fall ^u x1 &1 fur!r1 t ! laws ( d\ble refraction w be ^? giv5 by ,fresnel = light waves 9 a d\bly refract+ m$ium4 ,!re w be two waves 9 ! cry/al4 ,! di/urbance 9 ea* ( ^! w be plane pol>is$2 _! velocity & ! position ( _! plane ( pol>isation c be f\nd f ! direction 9 :i* !y are travell+ by ,fresnel's con/ruction exactly4 ,maxwell's !ory1 !n1 w\ld appe> to indicate "s close connection betwe5 electric waves & ^? ( light4 ,f>aday's exp]im5ts on ! rotation ( ! plane ( pol>isation by magnetic =ce %ew "o ph5om5on 9 :i* ! two are connect$1 & ,maxwell endeav\r$ to apply 8 !ory to expla9 ?is4 ,"h1 h[ev]1 x became necess>y to introduce an additional hypo!sis--!re mu/ be "s connection betwe5 ! motion ( ! e!r to :i* magnetic =ce is due & t :i* con/itutes light4 ,x is impossible to give a me*anical acc\nt ( ! rotation ( ! plane ( pol>isation )\t "s assumption z to ! relation betwe5 ^! two k9ds ( motion4 ,maxwell1 !re=e1 supposes ! l9e> displacem5ts ( a po9t 9 ! e!r to be ^? :i* give rise to light1 :ile ! compon5ts ( ! magnetic =ce are connect$ ) ^! 9 ! same way z ! compon5ts ( a vortex 9 a liquid 9 vortex motion are connect$ ) ! displacem5ts ( ! liquid4 ,he fur!r assumes ! exi/5ce ( a t]m ( special =m 9 ! expression = ! k9etic en]gy1 & f ^! assumptions he d$uces ! laws ( ! propagation ( pol>is$ light 9 a magnetic field4 ,^! laws agree 9 ! ma9 ) ! results ( ,v]det's exp]im5ts4 ,,*apt] ,x4 ,,developm5t ,,( ,,maxwell',s ,,!ory4 ,we h endeav\r$ 9 ! prec$+ pages to give "s acc\nt ( ,maxwell's contributions to electrical !ory & ! physics ( ! e!r4 ,we mu/ n[ consid] v briefly :at evid5ce !re is to support ^! views4 ,at ,maxwell's dea? su* evid5ce1 ?\gh /rong1 0 indirect4 ,8 support]s 7 limit$ to "s few ,engli%-speak+ pupils1 "y & en?usia/ic1 :o 7 conv9c$1 x may be1 9 no small measure1 by ! affection & rev]5ce ) :i* !y reg>d$ _! ma/]4 ,abroad 8 views _h made v little way4 ,9 ! la/ words ( 8 book he writes1 speak+ ( v>i\s di/+ui%$ work]s-- 8,!re appe>s to be 9 ! m9ds ( ^! em95t m5 "s prejudice1 or priori objection1 aga9/ ! hypo!sis ( a m$ium 9 :i* ! ph5om5a ( radiation ( light & heat1 & ! electric actions at a di/ance1 take place4 ,x is true t1 at "o "t1 ^? :o speculat$ z to ! causes ( physical ph5om5a 7 9 ! habit ( acc\nt+ = ea* k9d ( action at a di/ance by means ( a special !rial fluid1 ^: function & prop]ty x 0 to produce ^! actions4 ,!y fill$ all space ?ree & f\r times ov] ) !rs ( diff]5t k9ds1 ! prop]ties ( :i* 7 inv5t$ m]ely to #8save appe>ances1' s t m rational enquir]s 7 will+ r to accept n only ,newton's def9ite law ( attraction at a di/ance1 b ev5 ! dogma ( ,cotes1#fd t action at a di/ance is "o ( ! prim>y prop]ties ( matt]1 & t no explanation c be m intelligible ?an ?is fact4 ,h5ce ! undulatory !ory ( light has met ) mu* opposition1 direct$ n aga9/ its failure to expla9 ! ph5om5a1 b aga9/ its assumption ( ! exi/5ce ( a m$ium 9 :i* light is propagat$4 8,we h se5 t ! ma!matical expression = electro-dynamic action l$1 9 ! m9d ( ,gauss1 to ! conviction t a !ory ( ! propagation ( electric action 9 "t w\ld be f\nd to be ! v key-/one ( electro-dynamics4 ,n[ we are unable to conceive ( propagation 9 "t1 except ei!r z ! flight ( a mat]ial sub/ance ?r\gh space1 or z ! propagation ( a condition ( motion1 or /ress1 9 a m$ium already exi/+ 9 space4 8,9 ! !ory ( ,neumann1 ! ma!matical conception call$ pot5tial1 :i* we are unable to conceive z a mat]ial sub/ance1 is suppos$ to be project$ f "o p>ticle to ano!r 9 a mann] :i* is q indep5d5t ( a m$ium1 & :i*1 z ,neumann has himself po9t$ out1 is extremely diff]5t f t ( ! propagation ( light4 8,9 ! !ories ( ,riemann & ,betti x w\ld appe> t ! action is suppos$ to be propagat$ 9 a mann] some:at m simil> to t ( light4 8,b 9 all ( ^! !ories ! "q naturally occurs3--,if some?+ is transmitt$ f "o p>ticle to ano!r at a di/ance1 :at is its condition aft] x has left "o p>ticle & be=e x has rea*$ ! o!r8 ,if ?is some?+ is ! pot5tial en]gy ( ! two p>ticles1 z 9 ,neumann's !ory1 h[ are we to conceive ?is en]gy z exi/+ 9 a po9t ( space1 co9cid+ nei!r ) ! "o p>ticle nor ) ! o!r8 ,9 fact1 :5ev] en]gy is transmitt$ f "o body to ano!r 9 "t1 !re mu/ be a m$ium or sub/ance 9 :i* ! en]gy exi/s aft] x leaves "o body & be=e x rea*es ! o!r1 = en]gy1 z ,torricelli#fe rem>k$1 #8is a qu9tess5ce ( s subtle a nature t x _c be conta9$ 9 any vessel except ! inmo/ sub/ance ( mat]ial ?+s4' ,h5ce all ^! !ories lead to a conception ( a m$ium 9 :i* ! propagation takes place1 & if we admit ?is m$ium z an hypo!sis1 ,i ?9k x ought to occupy a prom95t place 9 our inve/igations1 & t we ought to endeav\r to con/ruct a m5tal repres5tation ( all ! details ( its action1 & ?is has be5 my con/ant aim 9 ?is treatise40 ,let u see1 !n1 :at 7 ! exp]im5tal gr\nds 9 ,maxwell's day = accept+ z true 8 views on electrical action1 & h[ s9ce !n1 by ! g5ius ( ,he9ri* ,h]tz & ! lab\rs ( 8 foll[]s1 ^? gr\nds h be5 r5d]$ s sure t ne>ly ! :ole progress ( electrical sci5ce dur+ ! la/ tw5ty ye>s has consi/$ 9 ! developm5t ( ideas :i* are to be f\nd 9 ! 8,treatise on ,electricity & ,magnetism40 ,! purely electrical consequ5ces ( ,maxwell's !ory 7 ( c\rse 9 accord ) all kn[n electrical obs]vations4 ,! equations ( ! field acc\nt$ = ! electro-magnetic =ces obs]v$ 9 v>i\s exp]im5ts1 & f !m ! laws ( electro-magnetic induction c\ld be correctly d$uc$2 b !re 0 no?+ v special 9 ?is4 ,simil> equations _h be5 obta9$ f ! !ory ( action at a di/ance by v>i\s writ]s2 9 fact1 ,helmholtz's !ory1 bas$ on ! mo/ g5]al =m ( expression = ! =ce betwe5 two elem5ts ( curr5t consi/5t ) c]ta9 exp]im5ts ( ,ampre's1 0 m g5]al 9 its "* ?an ,maxwell's4 ,! de/ructive features ( ,maxwell's !ory 73 7#a7 ,! assumption t all curr5ts fl[ 9 clos$ circuits4 7#b7 ,! idea ( en]gy resid+ ?r\gh\t ! electro-magnetic field 9 consequ5ce ( ! /ra9s & /resses set up 9 ! electro-magnetic m$ium by ! actions to :i* x 0 subject4 7#c7 ,! id5tification ( ?is electro-magnetic m$ium ) ! lum9if]\s e!r1 & ! consequ5t view t light is an electro-magnetic ph5om5a4 7#d7 ,! view t electro-magnetic =ces arise entirely f /ra9s & /resses set up 9 ! e!r2 ! electro/atic *>ge ( an insulat$ conductor be+ "o ( ! =ms 9 :i* ! e!r /ra9 is manife/$ to u4 7#e7 ,a dielectric "u ! action ( electric =ce is said to become pol>is$1 &1 accord+ to ,maxwell 7vol4 i4 p4 #acc71 all electrification is ! residual effect ( ! pol>isation ( ! dielectric4 ,n[ x mu/1 ,i ?9k1 be admitt$ t 9 ,maxwell's day !re 0 direct pro( ( v few ( ^! propositions4 ,no "o has ev5 yet s measur$ ! displacem5t curr5ts 9 a dielectric z to %[ t ! total fl[ across e section ( a circuit is at any giv5 mom5t ! same1 ?\gh !re are o!r exp]im5ts ( an indirect "* :i* h n[ completely ju/ifi$ ,maxwell's hypo!sis4 ,exp]im5ts by ,s*ill] & ,von ,helmholtz prove x is true t "s action 9 ! dielectric mu/ be tak5 into consid]ation 9 any satisfactory !ory2 !y !re=e upset v>i\s !ories bas$ on direct action at a di/ance1 8b !y tell u no?+ z to :e!r any special =m ( ! dielectric !ory1 su* z ,maxwell's or ,helmholtz's1 is true or n40 7,j4 ,j4 ,?omson1 8,report on ,electrical ,!ories10 ,b4,a4 ,report1 #ahhe1 p4 #adi47 ,:5 ,maxwell di$ !re _h be5 little if any exp]im5tal evid5ce z to ! /resses set up 9 a body by electric =ce4 ,fontana1 ,govi1 & ,dut] _h all obs]v$ t *anges take place 9 ! volume ( ! dielectric ( a cond5s] :5 x is *>g$4 ,qu9cke _h tak5 up ! "w1 & ! fir/ ( 8 classic pap]s on ?is subject 0 publi%$ 9 #ahhj1 ! ye> foll[+ ,maxwell's dea?4 ,maxwell himself 0 fond ( %ew+ an exp]im5t 9 :i* a *>g$ insulat$ sph]e 0 br\ght ne> to ! surface ( p>aff92 ! /ress on ! surface causes a heap+ up ( ! p>aff9 "u ! sph]e4 ,k]r _h %ewn 9 #ahge t _m sub/ances become d\bly refract+ "u electric /ress2 8 complete det]m9ation ( ! laws ( ?is action 0 publi%$ at a lat] date4 ,z to direct measurem5ts on electric waves1 !re 7 none2 ! value ( ! velocity ) :i*1 if ,maxwell's !ory 7 true1 !y mu/ travel _h be5 det]m9$ f electrical obs]vations ( q a diff]5t "*4 ,web] & ,kohlraus* _h measur$ ! value ( ,k = air1 = :i* is unity1 & f _! obs]vations x foll[s t ! value ( ! wave velocity = electro-magnetic waves is ab\t #ca #aj c5timetres p] second4 ,! velocity ( light 0 kn[n1 f ! exp]im5ts ( ,fizeau & ,f\cault1 to h ab\t ?is value1 & x 0 ! ne> co9cid5ce ( ^! two values :i* l$ ,maxwell to write 9 #ahfd3-- 8,! agreem5t ( ! results seems to %[ t light & magnetism are affections ( ! same sub/ance1 & t light is an electro-magnetic di/urbance propagat$ ?r\gh ! field accord+ to electro-magnetic laws40 ,by ! "t ! fir/ edition ( ! 8,electricity & ,magnetism0 0 publi%$1 ,maxwell & ,?omson 7,"l ,kelv97 _h bo? made det]m9ations ( ,k1 & _h %ewn t = air at lea/ ! result+ value = ! velocity ( electro-magnetic waves 0 v ne>ly t ( light4 ,= o!r sub/ances at t date ! obs]vations 7 few] /ill4 ,gibson & ,b>clay _h det]m9$ ! specific inductive capacity ( p>aff91 & f\nd t its squ>e root 0 #adje1 :ile its refractive index = long waves is #adbb4 ,maxwell himself ?\ght t if a simil> agreem5t c\ld be %ewn to hold = a numb] ( sub/ances1 we %\ld be w>rant$ 9 conclud+ t 8! squ>e root ( ,k1 ?\gh x may n be ! complete expression = ! index ( refraction1 is at lea/ ! mo/ important t]m 9 x40 ,betwe5 ?is "t & ,maxwell's dea? en\gh _h be5 done to m ?an ju/ify ?is /atem5t4 ,x 0 cle> f ! obs]vations ( ,boltzmann1 ,sil[1 ,hopk9son1 & o!rs t !re 7 _m sub/ances = :i* ! squ>e root ( ! specific inductive capacity 0 v ne>ly inde$ equal to ! refractive index1 & good reason _h be5 giv5 :y 9 "s cases !re %\ld be a consid]able diff]5ce betwe5 ! two4 ,hopk9son f\nd t 9 ! case ( glass ! diff]5ces 7 v l>ge1 & !y h s9ce be5 f\nd to be consid]able = mo/ solids exam9$1 ) ! exception ( p>aff9 & sulphur4 ,= petroleum oil1 b5z9e1 tolu5e1 c>bon-bisulphide1 & "s o!r liquids ! agreem5t betwe5 ,maxwell's !ory & exp]im5t is close4 ,= ! fatty oils1 su* z ca/or oil1 olive oil1 sp]m oil1 neatsfoot oil1 & also = e!r1 ! diff]5ces are consid]able4 ,x seems probable t ! reason = ?is diff]5ce lies 9 ! fact t1 9 ! light waves1 we are deal+ ) ! wave velocity ( a di/urbance ( an extremely %ort p]iod4 ,n[1 we "k t ! sub/ances m5tion$ %ew optical disp]sion1 & we h at pres5t no completely satisfactory !ory f :i* we c calculate1 f exp]im5ts on v %ort waves1 :at ! velocity = v long waves w be4 ,9 mo/ cases ,cau*y's =mula has be5 us$ to obta9 ! numb]s giv54 ,! value ( ,k1 h[ev]1 z f\nd by exp]im5t1 corresponds to ^! inf9itely long waves1 & to quote ,pr(essor ,j4 ,j4 ,?omson's words1 8! m>vel is n t !re %\ld n be sub/ances = :i* ! relation ,k does n hold1 b t !re %\ld be any = :i* x does40#ff ,x has be5 %ewn1 moreov]1 bo? by ,pr(essor ,j4 ,j4 ,?omson himself & by ,blondlot1 t :5 ! value ( ,k is measur$ "u v rapidly v>y+ electrifications1 *ang+ at ! rate ( ab\t #be1jjj1jjj to ! second1 ! value ( ! inductive capacity = glass is r$uc$ f ab\t #fh or #g to ab\t #bg2 ! squ>e root ( ?is is #af1 :i* does n diff] mu* f its refractive index4 ,! values ( ! inductive capacity ( p>aff9 & sulphur1 :i* x w be rememb]$ agree fairly ) ,maxwell's !ory1 7 f\nd to be n greatly diff]5t 9 ! /eady & 9 ! rapidly v>y+ field4 ,on ! o!r h&1 "s exp]im5ts ( ,arons & ,rub5s 9 rapidly v>y+ fields lead to values :i* d n diff] greatly f ^? giv5 by o!r me?ods4 ,! !ory1 h[ev]1 ( ^! exp]im5ts seems op5 to criticism4 ,to attempt any?+ l a complete acc\nt ( mod]n v]ifications ( ,maxwell's views & mod]n developm5ts ( 8 !ory is a task beyond our limits1 b an acc\nt ( ,maxwell writt5 9 #ahie w\ld be incomplete )\t a ref]5ce to ! "w ( ,he9ri* ,h]tz4 ,maxwell told u :at ! prop]ties ( electro-magnetic waves 9 air mu/ be4 ,h]tz#fg 9 #ahhg enabl$ u to measure ^? prop]ties1 & ! measurem5ts h v]ifi$ completely ,maxwell's views4 ,! me?od ( produc+ electrical oscillations 9 a conductor _h long be5 kn[n4 ,?omson & ,von ,helmholtz _h bo? po9t$ x out4 ,s*ill] _h exam9$ su* oscillations 9 #ahgd1 & _h det]m9$ ! inductive capacity ( glass by _! means1 us+ oscillations ^: p]iod v>i$ f #jjjjef to #jjjab ( a second4 ,^! oscillations 7 produc$ by dis*>g+ a cond5s] ?r\gh a coil ( wire hav+ self-induction4 ,if ! electrical resi/ance ( ! coil be n too great1 ! *>ge oscillates backw>ds & =w>ds betwe5 ! plates ( ! cond5s] until its en]gy is dissipat$ 9 ! heat produc$ 9 ! wire1 & 9 ! electro-magnetic radiations :i* leave x4 ,! p]iod ( ^! oscillations "u prop] conditions is giv5 by ! =mula ,t #b7;,,cl7 :]e ,l1 ! coeffici5t ( self induction1 & ,c ! capacity ( ! cond5s]4 ,^! quantities c be calculat$1 & h5ce ! "t ( an oscillation is kn[n4 ,f su* an arrangem5t waves radiate out into space4 ,if we c\ld measure by any me?od ! l5g? ( su* a wave we c\ld det]m9e its velocity by divid+ ! wave l5g? by ! p]iod4 ,b x is cle> t s9ce ! velocity is comp>able ) t ( light ! wave l5g? w be enorm\s1 unless ! p]iod is v %ort4 ,?us1 a wave1 travell+ ) ! velocity ( light1 ^: p]iod 0 #jjja second1 su* z ! waves ,s*ill] work$ )1 w\ld h a l5g? ( #jjja #cj1jjj1jjj1jjj or #c1jjj1jjj c5timetres1 & w\ld be q unmeasurable4 ,be=e measurem5ts on electric waves c\ld be made x 0 necess>y 7#a7 to produce waves ( suffici5tly rapid p]iod1 7#b7 to devise means to detect !m4 ,?is is :at ,h]tz did4 ,! wave l5g? ( ! electrical oscillations c be r$uc$ by r$uc+ ei!r ! electrical capacity ( ! sy/em1 or ! coeffici5t ( self-induction ( ! wire4 ,h]tz adopt$ bo? ^! exp$i5ts4 ,8 vibrator1 9 "s ( 8 m important exp]im5ts1 consi/$ ( two squ>e brass plates #dj cm4 9 ! side4 ,to ea* ( ^! is atta*$ a piece ( copp] wire ab\t #cj cm4 9 l5g?1 & ea* wire ends 9 a small highly-poli%$ brass ball4 ,! plates are plac$ s t ! wires lie 9 ! same /raight l9e1 ! brass balls be+ sep>at$ by a v small air gap4 ,! two plates are !n *>g$1 ! "o positively ! o!r negatively1 until ! insulation resi/ance ( ! air gap breaks d[n & a dis*>ge passes across4 ,"u ^! conditions ! dis*>ge is oscillatory4 ,x does n consi/ ( a s+le sp>k1 b ( a s]ies ( sp>ks1 :i* pass & repass 9 opposite directions1 until ! en]gy ( ! orig9al *>ge is radiat$ into space or dissipat$ z heat2 ! plates are !n re*>g$ & ! process repeat$4 ,9 ,h]tz's exp]im5ts ! oscillator 0 *>g$ by be+ connect$ to ! second>y t]m9als ( an induction coil4 ,9 #ahhc ,pr(essor ,fitzg]ald _h call$ att5tion to ?is me?od ( produc+ electric waves 9 air1 & _h giv5 two metres z ! m9imum wave l5g? :i* might be atta9$4 ,9 #ahgj ,h]r von ,bezold _h actually made obs]vations on ! propagation & reflection ( electrical oscillations1 b 8 "w1 publi%$ z a prelim9>y communication1 _h attract$ little notice4 ,h]tz 0 ! fir/ to und]take 9 #ahhg 9 a sy/ematic mann] ! inve/igation ( ! electric waves 9 air :i* proce$ f su* an oscillator ) a view to te/+ v>i\s !ories ( electro-magnetic action4 ,x rema9$1 h[ev]1 necess>y to devise an app>atus = detect+ ! waves4 ,:5 ! waves are incid5t on a conductor1 electric surg+s are set up 9 ! conductor1 & may1 "u prop] conditions1 be obs]v$ z t9y sp>ks4 ,h]tz us$ z 8 detector a loop ( wire1 ! ends ( :i* t]m9at$ 9 two small brass balls4 ,! wire 0 b5t s t ! balls 7 v close toge!r1 & ! sp>ks c\ld be se5 pass+ across ! t9y air gap :i* sep>at$ !m4 ,su* a wire w h a def9ite p]iod ( its own = oscillations ( electricity ) :i* x may be *>g$1 & if ! frequ5cy ( ! electric waves :i* fall on x agrees ) t ( ! waves :i* x c itself emit1 ! oscillations :i* are set up 9 ! wire w be /rong] ?an "u o!r conditions1 ! sp>ks se5 w be m brilliant4#fh ,h]tz's resonator 0 a circle ( wire ?irty-five c5timetres 9 radius1 ! p]iod = su* a resonator w\ld1 he calculat$1 be ! same z t ( 8 vibrator4 ,!re is1 h[ev]1 v consid]able difficulty 9 det]m9+ ! p]iod ( an electric oscillator f its dim5sions1 & ! value obta9$ f calculation = t ( ,h]tz's radiator is n v tru/wor?y4 ,! complete p]iod is1 h[ev]1 comp>able ) two "o hundr$? million?s ( a second2 9 8 orig9al pap]s1 ,h]tz1 ?r\gh an error1 gave a value great] ?an ?is4 ,) ^! arrangem5ts ,h]tz 0 able to detect ! pres5ce ( electrical radiation at consid]able di/ances f ! radiator2 he 0 also able to measure its wave l5g?4 ,9 ! case ( s\nd waves ! exi/5ce ( nodes & loops =m$ "u prop] conditions is well kn[n4 ,:5 waves are directly reflect$ f a flat surface1 int]f]5ce takes place betwe5 ! incid5t & reflect$ waves1 /ation>y vibrations are set up1 & nodes & loops--places1 t is1 ( m9imum & ( maximum motion respectively--are =m$4 ,! position ( ^! nodes & loops c be det]m9$ by ! aid ( suitable app>atus1 & x c be %ewn t ! di/ance betwe5 two consecutive nodes is half ! wave l5g?4 ,simil>ly :5 electrical vibrations fall on a reflector1 a l>ge flat surface ( metal1 = example1 /ation>y vibrations due to ! int]f]5ce betwe5 ! incid5t & reflect$ waves are produc$1 & ^! give rise to electrical nodes & loops4 ,! position ( su* nodes & loops c be f\nd by ! use ( ,h]tz's app>atus1 or 9 o!r ways1 & h5ce ! l5g? ( ! electrical waves c be f\nd4 ,! exi/5ce ( ! nodes & loops %ews t ! electric effects are propagat$ by wave motion4 ,! l5g? ( ! waves is f\nd to be def9ite1 s9ce ! nodes & loops recur at equal int]vals ap>t4 ,if x be assum$ t ! frequ5cy is kn[n1 ! velocity ( wave propagation c be det]m9$4 ,h]tz f\nd f 8 exp]im5ts t 9 air ! waves travell$ ) ! velocity ( light4 ,x appe>s1 h[ev]1 t !re 7 two errors 9 ! calculation :i* happ5$ to correct ea* o!r1 s t nei!r ! value ( ! frequ5cy giv5 9 ,h]tz's pap] nor ! wave l5g? obs]v$ is correct4 ,by modify+ ! app>atus x 0 possible to measure ! wave l5g? ( ! waves transmitt$ along a copp] wire1 & h5ce1 aga9 assum+ ! p]iod ( oscillation1 to calculate ! velocity ( wave propagation along ! wire4 ,h]tz made ! exp]im5t1 & f\nd f 8 fir/ obs]vations t ! waves 7 propagat$ along ! wire ) a f9ite velocity1 b t ! velocity diff]$ f t 9 air4 ,! half-wave l5g? 9 ! wire 0 only ab\t #bh metres2 t 9 air 0 ab\t #de metres4 ,n[1 ?is exp]im5t af=d$ a crucial te/ betwe5 ! !ories ( ,maxwell & ,von ,helmholtz4 ,accord+ to ! =m]1 ! waves d n travel 9 ! wire at all2 !y travel ?r\gh ! air alongside ! wire1 & ! wave l5g? obs]v$ by ,h]tz ought to h be5 ! same z 9 air4 ,accord+ to ,von ,helmholtz1 ! two velocities obs]v$ by ,h]tz %\ld h be5 diff]5t1 z1 inde$1 !y 71 & ! exp]im5t appe>$ to prove t ,maxwell's !ory 0 insuffici5t & t a m g5]al "o1 su* z t ( ,von ,helmholtz1 0 necess>y4 ,b o!r exp]im5ts h n l$ to ! same result4 ,h]tz himself1 us+ m rapid oscillations 9 "s lat] measurem5ts1 f\nd t ! wave l5g? ( ! electric waves f a giv5 oscillator 0 ! same :e!r !y 7 transmitt$ ?r\gh free space or conduct$ along a wire4#fi ,le*] & ,j4 ,j4 ,?omson h arriv$ at ! same result2 b ! mo/ complete exp]im5ts on ?is po9t are ^? ( ,s>as9 & ,de la ,rive4 ,x may be tak51 !n1 z e/abli%$ t ,maxwell's !ory is suffici5t1 & t ! great] g5]ality ( ,von ,helmholtz is unnecess>y4 ,9 a lat] pap] ,h]tz %[$ t electric waves c\ld be reflect$ & refract$1 pol>is$ & analys$1 j l light waves4 ,9 8 introduction to 8 8,collect$ ,pap]s0 he writes 7p4 #ai73-- 8,ca/+ n[ a glance backw>ds1 we see t by ! exp]im5ts above sket*$ ! propagation 9 "t ( a suppos$ action at a di/ance is = ! fir/ "t prov$4 ,?is fact =ms ! philosophic result ( ! exp]im5ts1 & inde$1 9 a c]ta9 s5se1 ! mo/ important result4 ,! pro( includes a recognition ( ! fact t ! electric =ces c dis5tangle !mselves f mat]ial bodies1 & c cont9ue to subsi/ z conditions or *anges 9 ! /ate ( space4 ,! details ( ! exp]im5ts fur!r prove t ! p>ticul> mann] 9 :i* ! electric =ce is propagat$ exhibits ! close/ analogy#gj ) ! propagation ( light2 inde$1 t x corresponds almo/ completely to x4 ,! hypo!sis t light is an electrical ph5om5on is ?us made highly probable4 ,to give a /rict pro( ( ?is hypo!sis w\ld logically require exp]im5ts ^u light itself4 8,:at we "h indicate z hav+ be5 accompli%$ by ! exp]im5ts is accompli%$ indep5d5tly ( ! correctness ( p>ticul> !ories4 ,nev]!less1 !re is an obvi\s connection betwe5 ! exp]im5ts & ! !ory 9 connection ) :i* !y 7 really und]tak54 ,s9ce ! ye> #ahfa sci5ce has be5 9 possession ( a !ory :i* ,maxwell con/ruct$ ^u ,f>aday's views1 & :i* we !re=e call ! ,f>aday-,maxwell !ory4 ,?is !ory affirms ! possibility ( ! class ( ph5om5a "h discov]$ j z positively z ! rema9+ electrical !ories are compell$ to d5y x4 ,f ! outset ,maxwell's !ory excell$ all o!rs 9 elegance & 9 ! abundance ( ! relations betwe5 ! v>i\s ph5om5a :i* x includ$4 8,! probability ( ?is !ory1 & !re=e ! numb] ( its adh]5ts1 increas$ f ye> to ye>4 ,b z long z ,maxwell's !ory dep5d$ solely ^u ! probability ( its results1 & n on ! c]ta9ty ( its hypo!ses1 x c\ld n completely displace ! !ories :i* 7 oppos$ to x4 8,! fundam5tal hypo!ses ( ,maxwell's !ory contradict$ ! usual views1 & did n re/ ^u ! evid5ce ( decisive exp]im5ts4 ,9 ?is connection we c be/ *>act]ise ! object & ! result ( our exp]im5ts by say+3 ,! object ( ^! exp]im5ts 0 to te/ ! fundam5tal hypo!ses ( ! ,f>aday-,maxwell !ory1 & ! result ( ! exp]im5ts is to confirm ! fundam5tal hypo!ses ( ! !ory40 ,s9ce ,maxwell's dea? volumes h be5 writt5 on electrical que/ions1 :i* h all be5 inspir$ by 8 "w4 ,! /&po9t f :i* electrical !ory is reg>d$ has be5 entirely *ang$4 ,! greate/ ma/]s ( ma!matical physics h f\nd1 9 ! developm5t ( ,maxwell's views1 a task t call$ = all _! p[]s1 & ! h>ve/ ( new tru?s :i* has be5 g>n]$ has prov$ mo/ ri*4 ,b :ile ?is is s1 ! "q is /ill (t5 ask$1 ,:at is ,maxwell's !ory8 ,h]tz himself concludes ! introduction j ref]r$ to ) 8 mo/ int]e/+ answ] to ?is "q4 ,pr(4 ,boltzmann has made ! !ory ! subject ( an important c\rse ( lectures4 ,po9c>1 9 ! introduction to 8 8,lectures on ,maxwell's ,!ories & ! ,electro-magnetic ,!ory ( ,light10 expresses ! difficulty1 :i* _m feel1 9 und]/&+ :at ! !ory is4 8,! fir/ "t10 he says1 8t a ,fr5* read] op5s ,maxwell's book a feel+ ( uneas9ess1 (t5 ev5 ( di/ru/1 is m+l$ ) 8 admiration4 ,x is only aft] prolong$ /udy1 & at ! co/ ( _m ef=ts1 t ?is feel+ is dissipat$4 ,"s great m9ds reta9 x always40 ,& aga9 he writes3 8,a ,fr5* savant1 "o ( ^? :o h mo/ completely fa?om$ ,maxwell's mean+1 said to me once1 #8,i und]/& ev]y?+ 9 ! book except :at is meant by a body *>g$ ) electricity4'0 ,9 consid]+ ?is "q1 ,po9c>'s own rem>k--8,maxwell does n give a me*anical explanation ( electricity & magnetism1 he is only conc]n$ to %[ t su* an explanation is possible0--is mo/ important4 ,we _c f9d 9 ! 8,electricity0 an answ] to ! "q--,:at is an electric *>ge8 ,maxwell did n pret5d to "k1 & ! attempt to give too great def9it5ess to 8 views on ?is po9t is apt to lead to a misconception ( :at ^? views 74 ,on ! old !ories ( action at a di/ance & ( electric & magnetic fluids attract+ accord+ to kn[n laws1 x 0 easy to be me*anical4 ,x 0 only necess>y to inve/igate ! mann] 9 :i* su* fluids c\ld di/ribute !mselves s z to be 9 equilibrium1 & to calculate ! =ces aris+ f ! di/ribution4 ,! problem ( assign+ su* a me*anical /ructure to ! e!r z w p]mit ( its ex]t+ ! action :i* occurs 9 an electro-magnetic field is a h>d] "o to solve1 & till x is solv$ ! "q--,:at is an electric *>ge8--mu/ rema9 unansw]$4 ,/ill1 9 ord] to grasp ,maxwell's !ory ?is k is n necess>y4 ,! prop]ties ( e!r 9 dielectrics & 9 conductors mu/ be q diff]5t4 ,9 a dielectric ! e!r has ! p[] ( /or+ en]gy by "s *ange 9 its configuration or its /ructure2 9 a conductor ?is p[] is abs5t1 ow+ probably to ! action ( ! matt] ( :i* ! conductor is compos$4 ,:5 we are said to *>ge an insulat$ conductor we really act on ! e!r 9 ! neighb\rhood ( ! body s z to /ore x ) en]gy2 if !re be ano!r conductor 9 ! field we _c /ore en]gy 9 ! e!r x conta9s4 ,z1 !n1 we pass f ! outside ( ?is conductor to its int]ior !re is a sudd5 *ange 9 "s me*anical quantity connect$ ) ! e!r1 & ?is *ange %[s itself z a =ce ( attraction betwe5 ! two conductors4 ,maxwell call$ ! *ange 9 /ructure1 or 9 prop]ty1 :i* occurs :5 a dielectric is ?us /or$ ) electro/atic en]gy1 ,electric ,displacem5t2 if we d5ote x by ,d1 !n ! electric =ce ,r is equal to #d;,d_/,k1 & h5ce ! en]gy 9 a unit ( volume is #b;,d_/,k1 :]e ,k is a quantity dep5d+ on ! insulator4 ,n[1 ,d1 ! electric displacem5t1 is a quantity :i* has direction z well z magnitude4 ,its value1 !re=e1 at any po9t c be repres5t$ by a /raight l9e 9 ! usual way2 inside a conductor x is z]o4 ,! total *ange 9 ,d1 :i* takes place all ov] ! surface ( a conductor z we ent] x f ! outside measures1 accord+ to ,maxwell1 ! total *>ge on ! conductor4 ,at po9ts at :i* ! l9es repres5t+ ,d ent] ! conductor ! *>ge is negative2 at po9ts at :i* !y leave x ! *>ge is positive2 along ! l9es ( ! displacem5t !re exi/s ?r\gh\t ! e!r a t5sion measur$ by #b;,d_/,k2 at "r angles to ^! l9es !re is a pressure ( ! same am\nt4 ,9 addition to ! above ! compon5ts ( ! displacem5t ,d mu/ satisfy c]ta9 relations :i* c only be express$ 9 ma!matical =m1 ! physical mean+ ( :i* x is difficult to /ate 9 non-ma!matical language4 ,:5 ^! relations are s express$ ! problem ( f9d+ ! value ( ! displacem5t at all po9ts ( space becomes det]m9ate1 & ! =ces act+ on ! conductors c be obta9$4 ,moreov]1 ! total *ange ( displacem5t on ent]+ or leav+ a conductor c be calculat$1 & ?is gives ! quantity :i* is kn[n z ! total electrical *>ge on ! conductor4 ,! =ces obta9$ by ! above me?od are exactly ! same z ^? :i* w\ld exi/ if we suppos$ ea* conductor to be *>g$ 9 ! ord9>y s5se ) ! quantities j f\nd1 & to attract or repel accord+ to ! ord9>y laws4 ,if1 !n1 we def9e electric displacem5t z t *ange :i* takes place 9 a dielectric :5 x becomes ! seat ( electro/atic en]gy1 & if1 fur!r1 we suppose t ! *ange1 :atev] x be me*anically1 satisfies c]ta9 well-kn[n laws1 & t 9 consequ5ce c]ta9 pressures & t5sions exi/ 9 ! dielectric1 electro/atic problems c be solv$ )\t ref]5ce to a *>ge ( electricity resid+ on ! conductors4 ,some?+ su* z ?is1 x appe>s to me1 is ,maxwell's !ory ( electricity z appli$ to electro/atics4 ,x is n necess>y1 9 ord] to und]/& x1 to "k :at *ange 9 ! e!r con/itutes electric displacem5t1 or :at is an electric *>ge1 ?\gh1 ( c\rse1 su* k w\ld r5d] our views m def9ite1 & w\ld make ! !ory a me*anical "o4 ,:5 we turn to magnetism & electro-magnetism1 ,maxwell's !ory develops itself naturally4 ,exp]im5t proves t magnetic induction is connect$ ) ! rate ( *ange ( electric displacem5t1 accord+ to ! laws already giv54 ,if1 !n1 we knew ! nature ( ! *ange to :i* ! "n 8electric displacem5t0 has be5 giv51 ! nature ( magnetic induction w\ld be kn[n4 ,! difficulties 9 ! way ( any me*anical explanation are1 x is true1 v great2 assum+1 h[ev]1 t "s me*anical conception ( 8electric displacem5t0 is possible1 ,maxwell's !ory gives a consi/5t acc\nt ( ! o!r ph5om5a ( electro-magnetism4 ,aga91 we h1 x is true1 an electro-magnetic !ory ( light1 b we d n "k ! nature ( ! *ange 9 ! e!r :i* affects our eyes ) ! s5sation ( light4 ,is x ! same z electric displacem5t1 or z magnetic induction1 or s9ce1 :5 electric displacem5t is v>y+1 magnetic induction always accompanies x1 is ! s5sation ( light due to ! comb9$ effect ( ! two8 ,^! que/ions rema9 unansw]$4 ,x may be t light is nei!r electric displacem5t nor magnetic induction1 b "s q diff]5t p]iodic *ange ( /ructure ( ! e!r1 :i* travels ?r\gh ! e!r at ! same rate z ^! quantities1 & obeys _m ( ! same laws4 ,9 ?is respect !re is a mat]ial diff]5ce betwe5 ! ord9>y !ory ( light & ! electro-magnetic !ory4 ,! =m] is a me*anical !ory2 x />ts f ! assumption t ! p]iodic *ange :i* con/itutes light is ! ord9>y l9e> displacem5t ( a m$ium--! e!r--hav+ c]ta9 me*anical prop]ties1 & f ^? prop]ties x d$uces ! laws ( optics ) m or less success4 ,"l ,kelv91 9 8 labile e!r1 has devis$ a m$ium :i* c\ld exi/ & :i* has ! necess>y me*anical prop]ties4 ,! p]iodic l9e> displacem5ts ( ! labile e!r w\ld obey ! laws ( light1 & f ! fundam5tal hypo!ses ( ! !ory1 a me*anical explanation1 reasonably satisfactory 9 its ma9 features1 c be giv5 ( mo/ purely optical ph5om5a4 ,! relations betwe5 light & electricity1 or light & magnetism1 are n1 h[ev]1 t\*$ by ?is !ory2 inde$1 !y _c be t\*$ )\t mak+ "s assumption z to :at electric displacem5t is4 ,9 rec5t ye>s v>i\s sugge/ions h be5 made z to ! nature ( ! *ange :i* con/itutes electric displacem5t4 ,"o !ory1 due to ,von ,helmholtz1 supposes t ! electro-k9etic mom5tum1 or vector pot5tial ( ,maxwell1 is actually ! mom5tum ( ! mov+ e!r2 accord+ to ano!r1 sugge/$1 x w\ld appe> orig9ally 9 a crude =m by ,*allis1 & develop$ )9 ! la/ few mon?s 9 v satisfactory detail by ,l>mor1 ! velocity ( ! e!r is magnetic =ce2 o!rs h be5 devis$1 b we are /ill wait+ = a second ,newton to give u a !ory ( ! e!r :i* %all include ! facts ( electricity & magnetism1 lum9\s radiation1 & x may be gravitation4#ga ,mean:ile we believe t ,maxwell has tak5 ! fir/ /eps t[>ds ?is discov]y1 & has po9t$ out ! l9es along :i* ! future discov]] mu/ direct 8 se>*1 & h5ce we claim = him a =emo/ place among ! lead]s ( ?is c5tury ( sci5ce4 ,,footnotes #a ,a full biographical acc\nt ( ! ,cl]k & ,maxwell families is giv5 9 a note by ,miss ,isabella ,cl]k 9 ! 8,life ( ,james ,cl]k ,maxwell10 & f ?is ! above brief /atem5t has be5 tak54 #b 8,life ( ,j4 ,c4 ,maxwell10 p4 #bf4 #c 8,life ( ,j4 ,c4 ,maxwell10 p4 #bg4 #d 8,life ( ,j4 ,c4 ,maxwell10 p4 #di4 #e 8,life ( ,j4 ,c4 ,maxwell10 p4 #eb4 #f 8,life ( ,j4 ,c4 ,maxwell10 p4 #ef4 #g 8,life ( ,j4 ,c4 ,maxwell10 p4 #fg4 #h 8,life ( ,j4 ,c4 ,maxwell10 p4 #ge4 #i ,pr(essor ,g>nett 9 ,nature1 ,novemb] #ac?1 #ahgi4 #aj 8,life ( ,j4 ,c4 ,maxwell10 p4 #aje4 #aa 8,life ( ,j4 ,c4 ,maxwell10 p4 #aaf4 #ab 8,life ( ,j4 ,c4 ,maxwell10 pp4 #abc-abi4 #ac 8,life ( ,j4 ,c4 ,maxwell10 p4 #aij4 #ad ,dean ( ,cant]bury4 #ae ,ma/] ( ,tr9ity4 #af 8,life ( ,j4 ,c4 ,maxwell10 p4 #agd4 #ag 8,life ( ,j4 ,c4 ,maxwell10 p4 #aie4 #ah 8,life ( ,j4 ,c4 ,maxwell10 p4 #bjg4 #ai 8,life ( ,j4 ,c4 ,maxwell10 p4 #bjh4 #bj 8,life ( ,j4 ,c4 ,maxwell10 p4 #baj4 #ba 8,life ( ,j4 ,c4 ,maxwell10 p4 #baa4 #bb 8,life ( ,j4 ,c4 ,maxwell10 p4 #baf4 #bc 8,life ( ,j4 ,c4 ,maxwell10 p4 #bef4 #bd 8,life ( ,j4 ,c4 ,maxwell10 p4 #bfg4 #be 8,life ( ,j4 ,c4 ,maxwell10 p4 #bfi4 #bf 8,life ( ,j4 ,c4 ,maxwell10 p4 #bgh4 #bg 8,life ( ,j4 ,c4 ,maxwell10 p4 #bib4 #bh 8,life ( ,j4 ,c4 ,maxwell10 p4 #cjc4 #bi 8,life ( ,j4 ,c4 ,maxwell10 p4 #bei4 #cj ,b4,a4 ,report1 ,newca/le1 #ahfc4 #ca 8,life ( ,j4 ,c4 ,maxwell10 p4 #cdj4 #cb 8,life ( ,j4 ,c4 ,maxwell10 p4 #ccb4 #cc 8,life ( ,j4 ,c4 ,maxwell10 p4 #ccf4 #cd ,! ,pr(essors :o 7 consult$ 7 ,*allis1 ,willis1 ,/okes1 ,cayley1 ,adams1 & ,live+4 #ce 8,life ( ,j4 ,c4 ,maxwell10 p4 #cdi4 #cf 8,life ( ,j4 ,c4 ,maxwell10 p4 #cha4 #cg 8,life ( ,j4 ,c4 ,maxwell10 p4 #cgi4 #ch ,an acc\nt ( ! laboratory is giv5 9 ,nature1 vol4 x41 p4 #aci4 #ci ,! ,*ancellor cont9u$ to take to ! end ( 8 life a w>m int]e/ 9 ! "w at ! laboratory4 ,9 #ahhg1 ! ,jubilee ye>1 z ,proctor--at ! same "t ,i held ! (fice ( ,demon/rator--x 0 my duty to accompany ! ,*ancellor & o!r (fic]s to ,w9dsor to pres5t an address f ! ,univ]sity to ,h] ,maje/y4 ,i 0 introduc$ to ! ,*ancellor at ,padd+ton1 & he at once began to "q me closely ab\t ! progress ( ! laboratory1 ! numb] ( /ud5ts1 & ! "w be+ done !re1 %[+ himself fully acqua9t$ ) rec5t progress4 #dj ,9 #ahid ! li/ conta9$1 9 ,"p ,,ii41 sixte5 names1 & 9 ,"p ,i41 "o hundr$ & ?ree names4 #da ,"u ! new regulations ,physics 0 remov$ f ! fir/ "p ( ! ,tripos & =m$1 ) ! m advanc$ p>ts ( ,a/ronomy & ,pure ,ma!matics1 a "p by itself1 to :i* only ! ,wrangl]s 7 admitt$4 ,?us ! numb] ( m5 enc\rag$ to read ,physics 0 v limit$4 ,?is p]nici\s sy/em 0 alt]$ 9 ! regulations at pres5t 9 =ce1 :i* came into action 9 #ahib4 ,"p ,i4 ( ! ,ma!matical ,tripos n[ conta9s ,heat1 ,elem5t>y ,hydrodynamics & ,s\nd1 & ! simpl] p>ts ( ,electricity & ,magnetism1 & c&idates = ?is exam9ation d come to ! laboratory1 ?\gh n 9 v l>ge numb]s4 ,! m advanc$ p>ts bo? ( ,ma!matics & ,physics are includ$ 9 ,"p ,,ii4 #db 8,life ( ,j4 ,c4 ,maxwell10 p4 #chc4 #dc 8,/atique ,exprim5tale et ,?orique des ,liquides s\mis aux seules ,=ces ,molculaires40 ,p> ,j4 ,plateau1 ,pr(esseur l',univ]sit de ,gaud4 #dd ,! 8,r$ ,lions0 are a club =m$ by ,memb]s ( ! ,briti% ,association to meet = relaxation aft] ! grav] lab\rs ( ! day4 #de 8,leonum arida nutrix40--,horace4 #df v4r41 endless4 #dg 8,life ( ,j4 ,c4 ,maxwell10 p4 #cid4 #dh 8,life ( ,j4 ,c4 ,maxwell10 p4 #djd4 #di ,9 8 8,hydrodynamics10 publi%$ 9 #agch1 ,daniel ,b]n\illi _h discuss$ ! con/itution ( a gas1 & _h prov$ f g5]al consid]ations t ! pressure1 if x arose f ! impact ( a numb] ( mov+ p>ticles1 mu/ be proportional to ! squ>e ( _! velocity4 7,see 8,pogg4 ,ann410 ,bd4 #ajg1 #ahei1 p4 #dij47 #ej ,! pro( is z foll[s3-- ,if be ! specific heat at con/ant volume1 at con/ant pressure1 & consid] a unit ( mass ( gas at pressure p & volume v1 let ! volume increase by an am\nt dv1 :ile ! temp]ature dy4 ,?us d,t d,t pdv ,b pv ,t_/m ,h5ce p be+ con/ant1 pdv d,t_/m ,!re=e #a_/m ,n[ suppose an am\nt ( heat1 d,h1 is giv5 to a s+le molecule & t its temp]ature is ,t4 ,its specific heat is 1 & d,h md,t ,b d,h d,t ,!re=e m ,h5ce #a_/m _/ ,?us 7#a #b_/7c77 ,& _/ ,!re=e #a #b_/7c7 ,or #b_/7c7-a77 #ea ,ow+ to an error ( calculation ! actual value obta9$ by ,maxwell f ^! obs]vations = ! coeffici5t ( viscosity is too great4 ,m rec5t obs]v]s h f\nd l[] values ?an ^? giv5 by him2 ! diff]5ce is ?us expla9$4 #eb ,/udi5 b] das ,glei*gewi*t d] leb5dig5 ,kraft zwis*5 bewegt5 mat]iell5 ,punkt5 ,sitz d4 k4 ,akad ,wi51 ,b& ,,lviii41 #ahfh4 #ec ,ano!r supposition :i* might be made1 & :i* is necess>y 9 ord] to expla9 v>i\s actions obs]v$ 9 a comp\nd gas "u electric =ce1 is t ! p>ts ( :i* a molecule is compos$ are cont9ually *ang+4 ,?us a molecule ( /eam consi/s ( two p>ts ( hydrog51 "o ( oxyg51 b a giv5 molecule ( oxyg5 is n always comb9$ ) ! same two molecules ( hydrog52 ! p>ticles are cont9ually *ang$4 ,9 ,maxwell's pap] an hypo!sis ( ?is k9d is n dealt )4 #ed ,nature1 vol4 #a41 p4 #aeb 7,decemb] #ac?1 #ahid74 #ee ,see pap]s by ,mr4 ,cap/ick1 ,phil4 ,trans41 vols4 #ahe-ahf4 #ef ,nature1 vol4 x4 #eg ,an hi/orical acc\nt ( ! developm5t ( ! sci5ce ( electricity w be f\nd 9 ! article 8,electricity0 9 ! ,encyclopdia ,britannica1 n9? edition1 by ,pr(essor ,*ry/al4 #eh ,?omson 7,"l ,kelv971 8,pap]s on ,electro/atics & ,magnetism10 p4 #ae4 #ei ,j4 ,j4 ,?omson1 ,b4,a41 ,report1 #ahhe1 pp4 #aji1 #aac1 ,report on ,electrical ,!ories4 #fj ,pap]s on 8,electro/atics10 etc41 p4 #bf4 #fa ,x is difficult to expla9 )\t analysis exactly :at is measur$ by ,maxwell's ,vector ,pot5tial4 ,its rate ( *ange at any po9t ( space measures ! electromotive =ce at t po9t1 s f> z x is due to v>iations ( ! electric curr5t 9 neighb\r+ conductors2 ! magnetic induction dep5ds on ! fir/ diff]5tial coeffici5ts ( ! compon5ts ( ! electro-tonic /ate2 ! electric curr5t is relat$ to _! second diff]5tial coeffici5ts 9 ! same mann] z ! d5sity ( attract+ matt] is relat$ to ! pot5tial x produces4 ,9 language :i* is n[ frequ5tly us$ 9 ma!matical physics1 ! electromotive =ce at a po9t due to magnetic induction is proportion$ to ! rate ( *ange ( ! ,vector ,pot5tial1 ! magnetic induction dep5ds on ! 8curl0 ( ! ,vector ,pot5tial1 :ile ! electric curr5t is measur$ by ! 8conc5tration0 ( ! ,vector ,pot5tial4 ,f a k ( ! ,vector ,pot5tial ^! o!r quantities c be obta9$ by processes ( diff]5tiation4 #fb ,! #d is introduc$ because ( ! sy/em ( units usually employ$ to measure electrical quantities4 ,if we adopt$ ,mr4 ,oliv] ,heaviside's 8rational units10 x w\ld disappe>1 z x does 9 7,b74 #fc ,= an exact /atem5t z to ! relation betwe5 ! directions ( ! l9es ( electric displacem5t & ( ! magnetic =ce1 ref]5ce mu/ be made to ,pr(essor ,poynt+'s pap]1 ,phil4 ,trans41 #ahhe1 ,"p ,,ii41 pp4 #bhj1 #bha4 ,! ideas are fur!r develop$ 9 a s]ies ( articles 9 ! ,electrician1 ,septemb]1 #ahie4 ,ref]5ce %\ld also be made to ,j4 ,j4 ,?omson's 8,rec5t ,rese>*es 9 ,electricity & ,magnetism40 #fd ,preface to ,newton's 8,pr9cipia10 #bnd edition4 #fe 8,lezioni ,accademi*e0 7,fir5ze1 #agae71 p4 #be4 #ff ,9 8 s5t5ce /&s = ! refractive index4 #fg ,h]tz's pap]s h be5 translat$ into ,engli% by ,d4 ,e4 ,jones1 & are publi%$ "u ! title ( ,electric ,waves4 #fh ,"s ( ! consequ5ces ( ?is electrical resonance h be5 v /rik+ly %[n by ,pr(essor ,oliv] ,lodge4 ,see ,nature1 ,febru>y #bj?1 #ahij4 #fi ,h]tz's orig9al results 7 no d\bt affect$ by waves reflect$ f ! walls & floor ( ! room 9 :i* he work$4 ,an iron /ove also1 :i* 0 ne> 8 app>atus1 may h _h a di/urb+ influ5ce2 b = all ?is1 x is to 8 g5ius & 8 brilliant a*ievem5ts t ! complete e/abli%m5t ( ,maxwell's !ory is due4 #gj ,! analogy does n consi/ only 9 ! 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