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Weber quoting Maxwell Zur Anseinandcrsetzun!!; zwit;chen der Weberschen Theorie del" Elektrizitat lind der emfkommenden lVIaxwelIschen Elektrodynaillik Koch Torres Assis, Campinas, Sao Paulo, Brasil, and Karl Heinrich \Vicdcrkehr, Hamburg Zusamrnenfassung Die Abhandlllllg spt7:t sidl mit del' Ablos\lll!-\ der iilterPIl Ekktrodynamik vou \Vilhdill \Ve- bef und Fran;. Npumunll durch die .\laxwf'lJschr Theoric im lebten Drittel des 19. .lahr- aus!'inClIHirr. AuflliingrT fiir die Darst.ellllng der Pl'oblcl11<Jtik sind <iiI" w€nigen i':ltatp, dk sidl bci VI/ilhe]m \Ve!wr findcn. Di(' Diskuf'sioll wUrci(' daIllals (lurch Carl Nculllanu lind Johann Karl Friedrich Z;ii1hwr gcfUhrt" Ikidc warell cngagienE' und !eidpIIschaftlidlP AnhiiTlger lind Vertei<iiger Sieht uml Darstl'lluIlg der Thl'orie von d('r ElekLrb:iUit" Streit,pnnkte (1) dk N<l,hwirkungHtlH'orie, die mit dem Feldkoll7Ppt identiHch illt unci 1m Gegel1H<l,tz zur (Pro- toLyp: c,t,anli, und (2) die Annalilne der ExiSlenz piner EkktrizitiiL \V("\H'r beharrte his ;;ulpt7.t auf scinPHl Konzept nnt! entwickeite ein ,\t,omnH)(\ell, d,u.; ab des angesehen wer- den kalln. bestand Lei den absoluten eiektrischpn :'\,Ia.i;sYHt,emen. J_ Cl. Ii\..'; d('lll Kohlransch-\VclwT-E::qJPrinwnt die LirhtgeHthwindigkeit heraU'" die flir ('lektnJInagnl'tiHthc l .. ichttheorie cine wiehtige Stiitze war. Da.s absolnte (\icnLe <lh Crul1dlagp fur die InternaLionalen 1881. Abstract This a.rticle deah-; with the of \Vilhelm \Veher's and FraIl;" NeUlllann's 01- dpr tlwory of electrodynamics by theory in the last Lhinl of thc 19th cenlury. St,arting-poini; and for the present.ation arc th(" few quotatiolls Lhat. Gill be found ill \\-'el)('r's The was mainly by C<lrl von Neumann und Jo- hann Karl Fricdrich Zi:jllner. Both were ("ngaged supporters and of \Veber's view of Poillts of coutrovefl<,Y were: (1) The theory of dose-range ei-rects. which is identical to :'\,Iaxwclh (:oncept of field and which in eontr<lst to the dic,tant )"ange theory' (protoype: !\lewton's gravitational and (2) the assumption of the exisLence uf un dpctTic.al suhHtallee. \V("hpr persi:-ted righl to the end in hiH concept, amI developed an atomic model that ca.n be reganlpd as an initial stage of the ltut.herforcl- Bohr atomic mod!'L ConscnC.us existed in the abe;olnte electrical J. Cl. '\Iaxwell inf!'rrpd the velocity of light from the Kohlrant>ch-Vi-'eb("T-experiment. \Veber'c. t'lecLro-magneLic e;ystPIll served i\.." a for the international units of nW<ll<ure in 1881. 53

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Weber quoting Maxwell

Zur Anseinandcrsetzun!!; zwit;chen der Weberschen Theorie del" Elektrizitat

lind der emfkommenden lVIaxwelIschen Elektrodynaillik

Andf(~ Koch Torres Assis, Campinas, Sao Paulo, Brasil,

and Karl Heinrich \Vicdcrkehr, Hamburg

Zusamrnenfassung Die Abhandlllllg spt7:t sidl mit del' Ablos\lll!-\ der iilterPIl Ekktrodynamik vou \Vilhdill \Ve­bef und Fran;. Npumunll durch die .\laxwf'lJschr Theoric im lebten Drittel des 19. .lahr­h\llldf'rt~ aus!'inClIHirr. AuflliingrT fiir die Darst.ellllng der Pl'oblcl11<Jtik sind <iiI" w€nigen i':ltatp, dk sidl bci VI/ilhe]m \Ve!wr findcn. Di(' Diskuf'sioll wUrci(' daIllals h,mpt~iicblich (lurch Carl Nculllanu lind Johann Karl Friedrich Z;ii1hwr gcfUhrt" Ikidc warell cngagienE' und !eidpIIschaftlidlP AnhiiTlger lind Vertei<iiger (\r-~r \\"f'bcr~dlPII Sieht uml Darstl'lluIlg der Thl'orie von d('r ElekLrb:iUit" Streit,pnnkte waf(~n (1) dk N<l,hwirkungHtlH'orie, die mit dem \laxwell~c1wn Feldkoll7Ppt identiHch illt unci 1m Gegel1H<l,tz zur FermvirkUllg-~theorie (Pro­toLyp: ~ewtonscheH Gravitati()lI~gesetz) c,t,anli, und (2) die Annalilne der ExiSlenz piner ~ub~tant.iellen EkktrizitiiL \V("\H'r beharrte his ;;ulpt7.t auf scinPHl Konzept nnt! entwickeite ein ,\t,omnH)(\ell, d,u.; ab Vor~tufe des Jlutherford-Hohr~chE'n At()lllIllOdcJl~ angesehen wer­den kalln. Konsen~ bestand Lei den absoluten eiektrischpn :'\,Ia.i;sYHt,emen. J_ Cl. lvI~wel1 Ii\..'; au~ d('lll Kohlransch-\VclwT-E::qJPrinwnt die LirhtgeHthwindigkeit heraU'" die flir ~eine ('lektnJInagnl'tiHthc l .. ichttheorie cine wiehtige Stiitze war. Da.s absolnte elektrornagneLi~che I\IaJ~SVHr,em (\icnLe <lh Crul1dlagp fur die InternaLionalen 'l\Iar~einheiten 1881.

Abstract

This a.rticle deah-; with the super~("Hsiun of \Vilhelm \Veher's and FraIl;" NeUlllann's 01-dpr tlwory of electrodynamics by :\IaxwcJr~ theory in the last Lhinl of thc 19th cenlury. St,arting-poini; and l)<-l~is for the present.ation arc th(" few quotatiolls Lhat. Gill be found ill \\-'el)('r's work~. The discu~Hi()1I was mainly p(~rforilled by C<lrl von Neumann und Jo­hann Karl Fricdrich Zi:jllner. Both were ("ngaged supporters and a(h-ocat(;~ of \Veber's view of elpctlicit.~'. Poillts of coutrovefl<,Y were: (1) The theory of dose-range ei-rects. which is identical to :'\,Iaxwclh (:oncept of field and which ~to(ld in eontr<lst to the dic,tant )"ange theory' (protoype: !\lewton's gravitational la~v), and (2) the assumption of the exisLence uf un dpctTic.al suhHtallee. \V("hpr persi:-ted righl to the end in hiH concept, amI developed an atomic model that ca.n be reganlpd as an initial stage of the ltut.herforcl- Bohr atomic mod!'L ConscnC.us existed in the abe;olnte electrical m(~a~urp.IIlent ~y~tellls. J. Cl. '\Iaxwell inf!'rrpd the velocity of light from the Kohlrant>ch-Vi-'eb("T-experiment. \Veber'c. ahsolutc~ t'lecLro-magneLic e;ystPIll served i\.." a ba~i~ for the international units of nW<ll<ure in 1881.

53

1 Introduction

Two of thc~ leading figure~ of XTXth century elenrodynamk~ were James Clerk II;Iaxwl'll (18.31 1870) and \Vilhelm Eduard \Yelwr (1804 1891), 27 ye;(trs oldc'r than \laxwC'i1 ([OJ

a portrait of \Yilhelm \Y,o'iwr see pal',e 8). It ic. well kllown ,hat :\1axwell quot(;d in hi~ papers on e[e~Lromagndislll of 18~3, 1864 amI 1868 the wOiks of \Veber, sl'e [II, 121. I:~]

and [-'1]. In Maxwell's "Jfreatisc on Electricity and Magnetism (1873), which illtwclm·{"cl to Continental Europe a new epoch of resC'areh into electricity, \Vilhdm \V<:'1)('r. !Hext ro i\.lidlael Faraday and VViliiam Thomson (Lord KelYin), is most fn"(juPIltly (l1lOt('ti, 15]. \Vhat if, airnofot unknown is that \V",iwr also quoted }laxwell a few times in his works. \Vilhelm \Ye!JPr had alrpady formulated a fullfiedl',ed theory of p[edr()(lynamics, which was acknowledged on the Conlinenl unlil lhe 1870's as one of the leading ones. logether with th(" studi("s of Fnm7. SeumanIl. It dealt with t.hp alr('atiy \wll-knO"wn pIWll()]ll('lla of mag-ndisHl ami diamapldi~IlI using a~ support the hypothp~es of (;It'ct.rical lllol('cular currents, Coulomb's law of plectrostaticC', Ampere's study of attraction <lJld n'\mbion of two E'1E'etrieal currents, amI Fara(by's work on induction. Thl' CE'nt.H)'! point of \\-'eiwr's theory was the basic law of electrical action, which he propou]](led in 18-'16, 16J. In \Yei){'r'~ writing~ I\-IaxwdI\ namp apppar;; only ~ix time~. \.\1(' give the~e instan("('s helow. and rdittt' them to their hiktoric<l.l nmt("xt. Thi~ is the t.opic ofthik work, n"Sllitmg from a systpm<l.tic perU~;i1 of hik pap("rk. All of th('"~(" citations an; in the fourth volume (1894) of VVeber'~ collected works, a &et of 6 volullles publi~hed during 1892 and 1891, 17[. It ~lj()uld OP ob~erved that there ;ire no index of names nor ~uhject. index in t.he~e yolumes.

2 First and Second Quotations

The fir~t quotation appears in a paper of 1871: "Electrodyna.mic Illea~menwllt~ relat.ing ~lH'­cially to ,ht; principle of the conseryation ofenprgy", [7, Vol. 4, pp. 247 299. H(~(, esp. p. 2GIJ. This pappr has already been translated into Engli~h, [B, see esp. p. nl. It is only all imli­teet citation, as he i~ quoting Tait's work and it i~ Tait that. cites \"]<tXWl'll'~ lIanH'. In thi~ work \Yeher ~how~ the" compatihilit.y of his fund<JIllenwl law of elenricitv d('snihing th(' interaction betv.,T(~n charged particlp~ wit.h the principle of con~(;rvation of ('lIprgy. At. th(~ end of Section 6 :vIaxwell's name appears in a footuote:

51

In Profl'ssor Taies very instructive work, 'A Sketch of TIH'IIllOd:dtalllics· (EdinbUIgh, 1868), the following passage occurs al page 76, ill referenc(' ~o the investigations of Riemann and LOr<?nL which appeared in Pogg('ndoIlr~ Annalen for 1867 [l'hil. ~lag. S. 4, vol. xxxiv, pp. 368 <Jllri 287J: "But t.h(' ill­vestigations of T hpse authors are emirely ha~E'd on \VE'iJE'r·k ina(hllissil)l", T h("lJr, of the forceH ex("rtpd Oil each orllPr by tn!J1]ing du:trir; l}(f,didf:.~, for which t.hp conkervatiun of energ~' i~ nOT tnit', while ::'vlaxwell's result is in perfect eOIl~i­st.(m("(' with tbat Kl"pat prillciple" This ,,~~ertion of Prof('s~or 'rait's ~e~('lllS to h(~ in contradiction with tIl(' ahow'. At pagr~ 56 of th(' ~anw work I'd1". Tai, m(;ntions t.hat Helmholt7 lI<i~ ba9'~d the doctrilH" of enprgy on Newton·", prin­cipl", awl un the following postulate: ":\Iatter consists of ultimate partid('s which exerL upon each oLher forces whose directions are Lho~e of Ow lille~

joining each pair of part.ides, and whose \llagnitude~ depend solely on tlw distances between t.he partic1e~." The cont.radiction bnwe(m the fundamental law of ekct.ricity ;;nd this post1ltatc i~ ('yident; belt. t.Iw contr<Jrlict.ion b(~tw('e·~ll

it awl the principif: of thf' co'n.lfTaatirJn of o!ngy is by no means E'vidE'nt., a disLincUoll which Professor Tai~ seems Lo have overlooked.

Clos(·l,. rekvant i~ tilt' f>econd quotation, which appear!; in a paper of 1878, the "eventh papl'r in thp fatuous ~l'rie;; of Elfxtr-odynamic Measll,n:mnifs, ]91, 5cr r:~p, p. 36;{ of Vol. ,j of \V('l)('r'~ vVf,r·h:. Thi;; quot(ltion deals with the ~(lllH~ t.opic and appcar;; in the first paragraph of t,hi~ papr'r, our ~ran;;latioll:

l1('lmholt7. lIIailltain(~d, and \ViIliam Thom~Oll, Tait and others agn~pd with him, that the general fundamental law of electrical adion pr('~ented ill the ~'ear 18'lG in thE:' Electrodynamic J\:le(ll'nrements1, to which waH added in Pog­geIl(!orlI's Ann,llen 1848, VoL 73, p. 229,2 the dcriY{~d potential of the dcct.ric fOIl'e, wa~ in contradiction with principle of thc con~('rvatioll of energy; ho­w('y('r C. Neuman)] and }Iaxwell demon~tra.tf~d the opposi~(', proving thar all ,'lTOl' Wfts madl~ in the prE'SPllLation of the theorem by Helmholtz, that the prill('ipil" of the cons('rv(ltion of energy i~ valid only for [or("l~s which dE'pE'nd 801d:1f on tlj(~ distanc<' . .'l

The ~t(lrt of til(> con[.rovers.y bd,ween \Vilhclm \Vpher and Hermann von HelIflholt~ (1821-18(4) dates back LO 1847. In hi~ fatuous your-Mill study On the ronseTl}ation of force H('llllholtz m1un(.aiJl('d, when considering cr:ntr(ll forces, t.ha~ the law propounded by \Ve­ber was at variance with ~he principle of the con5crv'l.tioll of energy. Illl, with English t.ran~lation in [12J. The rrH.<;on W(lH that in \Veber\ force, heyond t.hc 1/r 2 Conlombiall tCllll_ t,jH'l"(' wpr<' t,erillS dependin~ on tllE' relative velocit.y amI acceleration lw,tween the intt'ract.ing electrical charge;; (or rather cledrical particie;,)4. \'Veber had ~pecified in 18,'18 a t("rm for the pot(~nti(ll of eledrical encrg:v, [16J, with English translation in llOl-" Herma.ml von Helmholtz continned to at-g-ue ahout thiH problem in spvera.l treatises [rom 1870-187.';i, trying Lo e~tahlish a distinction between the hitherto concurring eledrical theorie~, ("s,,<;ellti­ally t)]O;;(~ of\Veber and :\Iaxwdl, [17, sep esp. pp_ 345, 636 aIUI647] atld 118, pp. 8748891_ Helmholtz tried to prove that two electrical p(lrticies, moving accoTding to \Veber's law, CaJI attain an infinitely high speed, which wonld contradict t.he principlE' of energy conser­vat.ioll. Thl' ~o-c(llled "crit.ical dis~Hllce" (\Vpber's "mole('ular ~ize, or dimension") play~ the deciHiw role in thi~ matter. \Veber dr:fended his position wit.h hiH ~tlldy of 1871, 1191 with E))glish fr(lI1Hiatioll in 181-

J'l'tr'r Gnthrie Tai~ now embraced iII his "Sketch of Thermodynamic~" (1868) thp alrca­d,Y obsol('w point of view of Helrnholt~ of 18'17, [20J. Abo ill the work "TreatiHe un :'\aturru l'itiloHophy" (l867) by \'V. ThoIllson and P. G. T(lit this criticism of \Veber'H law was re­peated, ]21], H. Helrnholt~ and G_ 'vV("rt.heim were responsihle for the German tr(ln~lat.ioll publi~hed in two parts (1871 and 1874), [22J and 123]. \Yeber'H law was ciesrribpd here as illter{'~li)lg <tnd el(")!;ant, bm also a;; a dangerous spcculation (3385). IIdmholt7. wrotp a pref;u:(> t.o t.h" translation, A dOHe hiE'nd of \Vilhelrn \Yeller, Johann harl Friedrich Zollner

IS,'" public-alion for tl,,' e~1 ablishmenc of' tlw Royal Saxonian Society of Seirncc. Leipzig 18,16. I\Vilbdm \Vpber'~ \\'(>rk,\ Vol. HI, p. :25. [7. Vol. .1, pp. 25-2141_1

21\\,ill1('hn \\""I)(,,-'~ \Verkc, Vol. ITT, p. 2'L~, [7, Vol. 3. pp_ 215-2"d. ~ee esp. p. 2451 with B"g,li~b transial.iolL ill 110, soe ~~p~("ially p. 5201.]

:lSee al~o Ad. ]1 .. Tny,'[: "Urher den allge",eiJl~ten Ausdru("k der in""ren POlentialkrafte eille~ Sy~1.(}ms bpWe!W'T malrrieller Punkle, w~lches sich all~ dem PriTicip der Glcichheit von \Virkllng und CpW'JI1NiIiulllg ('rgiebt" ll.-Iathrmat.ische Annalen, Vol. 13, p. 20 .

. 1\.vd)rr'~ for('e acting b~1.wpe" liJC electrical charg",~ C fl.ml e' 5Pparated b," a diAI,aIlce or is along the ~traiglol. linr. connecting them and is given by (ee ' /or 2 )(1 r2/':~I' + 2rf/C";;l'l_ Hprl''''' -= dr/dt, j' = d~'I"/dl.~ and elY is \Veber'A coIlsl.ant. In 1855-1856 \Vl'ber and Kohlrau~("h [OllIld rxpcrimentally itb w),lm:. "1'1' = 4.:394.:'0 x IOlJ rn.m/8, chat i~, e%eniinlly h Urnes the light ve1oril.y in air, [BJ, IHI aad IVil·

~\V~lwr's P()I.'~I1l.iitl energy j~ given by (eel/r)(l - f2/cfv l.

(1831 1882), saw t,hest' da.im.~ &'; frivolous and irrespOlIsihl('. In lilt' introductioll to jlis hook "Oil the l\at,lIre of COIiH~t.S- (Leip;>;ig 1872). p·l], he r('proadlCd Helmholtz for !lot havi!lg Lakf'n ('Hough Cill·,' to rt'<lch a man' ju.~t evaluatioil of the idpHS of a GPl'lllan ~('holar of snch great. merit a<; \Vil!whn \Vebcr. l\la."-.well, in his opposition to t.1l\> ('arliPT tllPo­rit's of pjpctr()(iynamics, ~how('J g[('ater respect for thl' nmtrilmt,iom; oj" his prf'd('("('ssors, ('sp('ciaIl.\' tlioM' of \Vilh(,lm \Veber.

The dOijc rivalry bC'l.wecn \VdH'r awl IIplmholtz had otiW[ <'au.<:.es. how('\·(>}". Tht' 1-0-

called "organic physicists", frmll til(' school of t.he physioiogil-j, Johannes I\fiilJpr in Berlin, wpn~: Erust \Vilhelm Riller VOII BrUcb.~ (1819 1892), Emil Du Dois-Rf'YllLond (1818 1896), Hermann von Helmholt:t., and, joining them, but not (·onsi<iering hilllsplf iI stu<ipnt of il.Iiillt'r, Carl LlJdwig (1816-1895). Tilt's(' lliPIl madt' it their task 1,0 pstablish ph~·siolol-\.\­

on a seipntifi(" ba<,is of chemist.ry and phy~ics. Th(' pioneers in this project. had iadpp(i bpPIl thp t,hre(' brothers \Veh('r: Ern.~t Hdllrid\ (1795 187H), ph~·sioiolQst. \Yillwlm Clinard, physicist, and Eduard Frkdridl (1806 1871), pIt.vsi{)logi~t. \ViUu;lm \Vp\)('r, ill part.iullat", supportpd his two hroth('rs in pleetrophysioloK\' an(] ill n'S{·a.r("hill!', huma.n walking ,u·tiyit.\·, rontribut,ing prf'cif.p nlE't,hods of mnasurPlllenr. and matll0matieal [('cording, 125] ilnd ]26, pp_ :18--'15]. Although tIl<' org,mlc physicists huilt on t.iL(' work dO)lc h~' E_ H_ and E. F_ \Velwr, a certaill spirit ofrivalr~' rievdop('(\. Tlwy b('lh~ved that their work llad lIot ilchkvpd thp recognition it d(,Sf'rvp<1. Elllil DnBois-RC.\"I11011d felt PVt'1I t.hat his wOTk waij a("ri\"('l~'

ijuppres,,;pd. In a lett.er of 1849 to C. Lu(lwig he YPlltt'd hif. f<'("lings about it, expn'ssing ('ven a degree of hatrt'd again~t. tItp \\'el)(']" brolhers. 127, pp. -19 53]. Ludwig, who ill 1865 became Ernst Heinrich \Veber'~ ~u{'ceij~or at Leip~ig. d('f(>ndpd th(' \Vd){'r bJ'()th('r~ in ili~

lettt'l"s. Ludwig saw in E. H_ \\'ebCI" th(' onc l"Pscar("hcr who had t'xt'rdSf'd the gn'ah-:;t infiu<,ncp upon hi~ tilinkillg, ]28, p. (lj. Tilt' rellown of the \VcI)('r bJ'(lth('r~ pakd sOI!l('wlmt UlljUStl~, in fan' of Tht' organi(" phyliici~t,,,. celt,j,ratl'd fOlluderli of modem ph.,"sioiopy. aud thdr con(.rihu(.i{)n~ are for thc most, part. llnd<~l'vahJ('d ill thc llistol'iral ;t(:{'oll!ll,s, [29] and [30[.

After hi~ hook Oil cOlllets, ZiiliTwr wrote ~('"pral more art,klf'~ in d{'('(·ll{'(' of \VPiwr·s viewpoints, inh'ndiIlg abo to !"('ply ill part to attadcli llladt' upon hillliit'lf. Tllf' t.oue i)('nlll)(, ~ha.rJlt'r and more polemic, awl t.ook on. 11I01'POVt'1'. a Ilatiollalilitie flavour, Th('s(' W('H' til{' .\'f·ars aft.cr t.ht' frau("o-Prussiau \Var, aud r ht' COlluding of t.he (:f'rIlH\n fit'it'h h~' Bi~liIar("k. ZiilhH'r WlIS a ~llpport,er 01· spiri LualislIl, which CHIne froIn England (s(';-Illc{'s with a 1l1('<liulIl. Lahll'-shakillg. ghosr1~' rapping Iloi~ps eTe ) and hp had h<'en d('('pivpd h.v a t.rickswr. HiI­oppollents ma(ln rich use of this La defaril(' his perf.onal r('putat,ioll, J':olln{'l"s atLacks \Wl'('

dirCCTed ill part.ic-ular against P_G. Tait, \Y. Thom:>on. E_ DI1 Doi:>-fif'.nnolld and John Tyndall, find hI' ('veIl fell ont with hi:> old fricnd C_ Ludwig'. Tll11~ Ziilll\cl' dHtlwg('d himsplf. His work Lowanh; tIl(' d('\"{'iopIIIPnt of 1(,lls-photography and tlw fO\llldillg of astroJlh~'sk~ was t,h{'n~hy uooillt'd (.0 r('maill larpply unknown to post('rity, 1.31] ilnd ]:32, pp. 19·1-205]. Tlip calL';c of \Vilhpllll \Vpher wa~ silllilarl~' Hot, well sen'pd by (til t.his.

Lt~T u:- !lOW look ,lt Zollner's work "Uplwr \Virkungen ill dip Fenw" - only t,lip n,!pyallt scientifk part., l:t1]. It is \.0 SOl)It' ex(pnT a reply to i\l<Jxwpll's di~~<'rrati{)ll "Oil <l}·t,iOIl at, a distancp" (1873), 1:3-1] (s('e also th<' Ia.st Chapt.er of :>"laxwell's Tr1'.I,Ii.lf:' ]fiJ). III Ziil!lIt'r·s work it is fcatnred t.ht' exchangp of ,·ic\\llOints thp for and agaiIl~t. of \\,'pJ)pr's plpd,rody­naIllic~ alld I\Iaxwell's elf'(·troIllagnptic field tiH'or:-. III \VpheI·s writillgs oup nlll find olll~· ,1 few reft'r<'ncc~ to what WHS Own a 11I0sl, highly topical argUllwnt_ \Veb{,l" wa,~ shy about, such dispnLes. ZiiIlIH'l", howe"er, wa.~ difft~r{'llt. \Ve can say ht' n'presPIlt.ed \Vdll'f, and wa.~ dearly Ina,<;ter of Thc English iilllgtlag<", having a good acquain(,anc(' lll~o with t.hp Ellglis)l publkatiolls rpl('Yant to this Hnbject. PerhapH he may wpll ha\'(> sometiul0s m·C'fl-llOl hi;. intended t.arget. Of \Vilhcll1l \\'p\lCr we know t.ilar h(, had a good cOIlunarld of FrPlwh, and

;:;6

Fig. 1: Johann Karl Fri0drich ZiillIlt'f (184:3·-IRS2)

lklll.~cll('," Idll~"llm l\iiinc1",,,. IJl\ :i.")07"i'

57

wrote letterH in French. Letters by him in £.ngli~h are not knowIl to Ub. He IIlU~t however had a cert.ain knowledge of English, for in 1838 he went. on a fairly long jOUrTlC'y t.hrough England, and met a number of scientists. In his article, Zollner reproduced ]V[axwcll's Illork largerly in German. In order to defend his theory of act.ion by contact (field thc'ory), \bx­well offered in hiH addresH the thesi~ That I\"ewton, while desr:ribing i,>TavitatioIl a.<; ~ubj",ct

to <l law of action at a di1;tance, yet had in mind anion b.Y contact, a tranHfer of force from om" ek,ment of v(lluInP (partide) to the next. Zmlner maintained, however, in cont.rast, t.hat the law of gravitation had been for )lewton an absolute and fundamental law, nol. eapabl" of further elucidat.ion, and in this he echoed most of the 19th century physiciHt~. Both }IaxweJl and Zollner reinforced their \"iewpoint~ with quot<lti()n~ frOlll )lewton, and Ziillncr also cited Imm(l.nuel Kant (II-; chief wit.neH~. The problplll ih ht.ill being dis("1lsHed today in the literature of hisTorical physicH. For Ziillner the views of I\Iaxweli and also \\-'. Thomson represenL a stcp-back of more Lhan LwO ccnLnries, which carns Lhem lhe 11iciOlame of "modcrn Cartesians".

For J\.1mcwell. Faraday is t.he initiator of a concept of continuum. Zollner, in conLras(., seeks to claim that Faraday stood for an atomistic con("C~pt of electricity. In our opinion, ,md indeed that of mo~t hi~torian~ of physicH, Farad(l.")' rpjecU~d the pxiht.ence of a snhst.ant.ial electrical charw~, and abo the exiHt.ence of atom~ and moleculps wit.h maSH. For him thprp were only force-field~, possibly bound to insub"tantial nudei, ]351. ]I;[axwell also writes in his Treatise on the subjc~ct of ekctroi~'sis: ''The electrificat.ion of a molenlle, howP\"l'r, though casily spoken of, is not so e(lsily conceived", [5, ~260, p. 3801. Thl' (Tucial point of \'Ileber's con("C~pt i~, in contra5t, the genuinc~ exi~tence of t.wo kinds of dect.rical atOltlH, Oil('

positiye charge aud the other negatiye chal"g'e. His cOIlcept was later OIl confirmed by H .. \. LorenL",'s Lheory of electrons.

\Vhen :vlaxwell began his study of electrical phenomena, he at first imIllerHell hilll~(·lf compidrly in Faraday's rea~onings. Finall.v, however, when writing his tn'at.i~e "On phYHiral lines of forc(," (1861), [2], he occupied him~elf more inten~ively wit.h \Vdwr's ·writings. Hr' adopted the result of a nH'aSUTemc~nt. of the relation~hip between the ahsoluw elect.ro~t'l.tic and the absolute electromagnetic charge, a.''; determined by R.wlolf Kohlransch and \Vilhelm \Veber. This was in fact the speed of light. and it was one of Lhe main poinLs helping Lowards the creation of the theory of the eledromagneLic nat.ure of lighL (186·1). PJ and ]36]. In Lhe introdudion LO his LreaLise "1\ d:v"namical Lheory of Lhe eledronwgnetic field", at t.he end of which he develops his electrodynamic t.heory of light., and aiHo conHidpr~ the (iu hiH opinion) <:l.dmirable writing~ of \Vilhelm \Veber, he ouly dpdinp~ to <In:t'pt the idea of actiou at a distaute forces. In a post("ard of 1871 addressed to Tait, 1\·1a.-..;:,,·ell now speaks directly, saying that. \Veber's law is fully in accord with the theory of energy conservaLioll, ]37, pp. 96-97].

That. HelmholtL;, \Villiam Thomson and TaiL Ivere wrong in supposing LhaL \Vebel'~ force was incompatible with the con~eryation of l'nl'rg~' wa~ ~hown not only by \Veller in hi~ paper of 1871, but alM) by :Vlaxwell himself in the iaHt chapter of the TY'HLt-IHI:, 1'), Vol. 2, Chapt. 23], [38, Chapt. 3J and [39, Chapt. llJ. Helmholt~ in 1847 had consid(>rrd ('('nllal forces whirh depend on position ami velocity, showing that th<'y were incompa.tibk wilh the principle of the conseryation of energy. \VebE'r's force la.w, on Lhe oLher han,d, lkpelld~ not only on the dist(lnce between th(" chargeH <lnd thpir relative ydocity. lmt. also Oil thpir relatiyp accelera.tion. This mort' general ca.'>e had Hot l)eell l"on~idel"ed by Helmholtz.

58

3 Third and Fifth Quotations Til(' sa1tl(' subjcct-areas arc tf(-~ated in the t,hin! (two cit.ations in tllf~ same page') ami fifLh quotatioIls, so that thcy ~hould bc di~cllssed t,ogdhel'. The third quotation comes from hi~ work of 1878, [9] and e~p. p. 395 of Vul. ,1 of Wplwr's Werke. III Scct.ion 8 of thi~ pappr Vi/cber i~ discu~~ing- t.he applicatioll to luminiferous ether all(\ to ga~ps of the theory of rcA('xion and ~c(!t.tel'illg of d("ctric raYH an:oniing t.o his theory ,md also thc works of Kr6nig- ,llld ClaU~i\lH, A dis("u~~ion of the wOl'ks of Krollig and Cl"u~ius Gill be found in I-m, Vol. 1 pp. 193-81, while eomn1(-"nts about \Vebel"s di~russioll auout n~fiexion and scattering of particles can IlP found in ]40, Vol. 2, pp. 77- 791. The third qllotation runH as follow~, our tnlJlslation:

If iH posO'ible to Lran.';cribe thc hWOi found in tllP pl'eYiou~ Section [or t,hp l'efie-­xion and ~t;H,teriIlg of rays compo~(.'d of eiE'dric particlE's of thp same kind abo to rayH of pondel'abl(' IlIo]ccules. according to :\Io~ot,ti'~ ClHlcepUon ("OIllposed Tllol('cules. And when thps(' pondcrablp Illoleeulp~ are now g;J~ molecules, then a state of aggregation of t.hp gas wiU be built by thi~ means, which corrcsponds pntir(>ly to t.hp stale of ap,grE'gaLion according to Krijnig-Clall~ius's l,bcory of gascs, witilOul heing neecs:-;ary to ascribe to thE'se pondel'able molecules a special f(ll"Ill and el<l1>t.ieiL,,· ;In:ording to Kriinig, or a rppuisive force inversc­ly proportional to a higher pmwr of tlw distatlce according to ChmsillS and \!il)."",ll in particular When ll)pre is a plan', for example t.h(' ~pace, where there arp 1I0 pondenl1)1(' mole("ulp~, it is evident the possillility. th(!,t thE' panicles of one of the both component part~ of these ponderable molpcul(>s, t.hat is, (>ilhcr thE' positive or t,l](' m·gative rlpctric partidps, which an' ill this placp, that woul(l forIll in proj('("tiic lllotion likewis(' a body of special stalc of aggregation, now howev('r, as it b ('Olilposed only of electric particles of the same kind, should not b(' des­crilwd a~ pOllderablc l)odies, but. ;Jli irnponder(!blE' dhel' for ·which it would IH' valid the law~ of Illotioll deyclop(~(l equally by l'vhn:well (Phil. Transact. lR67) for dynamic media. namdy. the bws for the propagatioll of waves agreeing with tilE' l,tw~ for t.he Prop(!,gation of light wave~. Such conception of a placp fillpd wilh (! medium, composed of mutua.ll~' n'w"lliIlg partides, appear~ to \w po~~ihk, withOl.lt rigid border", only wiLh thp assumption of an extension unbounded to infinity, neV(-~rtheless it spemli possiblp a lirnitation of SUdl a m('dium in ;J finite placc without a rigid border according to !\losotti, i[ this lHf'diUIll SUTfollIub one of :,\IosotLi\ ponderable bodies, ,vhkh would ar.tnu:t thi~ lllcdiulll and il would be held 1).v this means.

Thr fifth quotation iH fi:mn the handwrilten p"lJ<'rs rrmaining afler \\leber's death, which were publiHlwd al the pnd of Vol. 4 ufhis Collected Pappr~ (l89-'I). [t is in thc rig-hth and la~(, work on thc ~eri("H of Elretrodynamic Mpasurement~, "Eledrodvnarllie mea~uremt'nLs, IMrticularly in respect t.o the ("(JIlnection of the [ulldarnelltal lawH of electricity with th(' law of gT,wit,ttioll" 17, Vol. 4, pp. 479 .'525, sec eHp. p. 48-11· In the second Spction of this paper \Ydwr i~ di~C1J~sing' the derivation of thp gravitaLional hw ba<.rd on his fund(!.lllental law of ('lectl'ieal action, following to the work of Z611ner. \Yeher i~ then ahlr to derive a law ,tnalo!!:ou~ t,o l\('wton's I(!;w of uniycrHai gravilation valid [or all distance~ r such tllat .,. » {I, whrf(' p iH a l'ypic<ll distanC(~ <lppearing in his theory, dHll'acterized by \Vebpr (l.'i

a mf,kcuiar dist.ance. OIlly for clht(!IICes of tlw order of p there would 1)(" d<:>viations from l\('wton;H law. The quotat.ion of \laxwell run~ (!s f()llow~, our translation:

Thes(' lllolpcular di~t,allce~ for pou<iel'auk g-(!li llIolE'('ulrs corne espccially illto

59

question <In:orrling t.o the dynamical theory of ga~cs_ Maxwell (On the D.Y­namical Tlwory of G<l);("~, l'hilo~_ Transact. VoL 1.')7, Part. L pp_ 49) fouw! already, that t.o explain the behaviour of gases 1'In:ol'ding to thi~ throry it is llecessary to suppose a law for t.lw r~fle"ion awl scattering of the ga~ molecuks which are in projectile motion when thpy collide (which cannot be an:ountpd f(Jr b<l);("d on Newton's law of gTayitation) espc'cially for (.he pnrpohe of thi~ explanation, which can be accounted by a force of repulsion proportional to the 5th powpr of the di~t<l.ncp beL ween the molecules, supposition (,haL howe­ver otherwise in nO way would lw ju~t.ifiablc_ - Every mhitrary suppo~iti())l like t.hi~ will be totally pjiminatP/I, if all ponderable moler,ulef-., (:mlse,quent.ly a]:-,o all ga~ molecules, are combinationk of equal (\mOUnLS of positiw' mul ne­gative electricitips. as for these moleculps the law of gravilalion is valid oilly for great distances, for If]olecnl<lf distances on the other hawl, aris(~s ~imilarly the law for the refiexion awl scattpring, a~ t.he theory d<.>yPloped by nH for the colJi»iol) of two electric Illolecnlps of t.he ~ame kind which me in projPctik mo­tion, an:ording- to the 7th publication of the LlectrodYllamic ]\-f<.>asureIllPnts, ArL. 7. (! -

In the treati~e of the third quotation \:Vilhdm \Vebel· look issup with [("newed obj('rtioll~ by Helmholtz to his basic law of electricity, dra,Ying support ±i-om arguments exprp~~cd by Carl :'-l'eumaiin. In addition to o~hcr matter~, \Vp!wr w<l.nt("d to say sOlllething about thp Htnlcture of the lUillinii'erouH ether. It W<lS supposed to cOIl;,ist oulv of (lllP kind of ba~ir dedrical particle, lIloying about. much like gru;-IlIoleculps. and [("pelling one another becaus(" of their equal electrical chMge (the same polarit~, positive Ol' uegatiy(' and the saTHe magnitude), without. touching one another directly. Th("se particles me not ::,uJ)jed. to the law of gnwitation: they arc imponderal)le, eYen thougli the'), po~ses~ a YC'l'y c-mall inertial mas::,. According to tlie conceptions of Ziillner a ponderable panicle will COllhic-t of ml equal number of poo.itiy(' a.nd Ilegative ha~ic elect-rical particles (the silllpipst ekcLrkal atoIlls). A po~it.ive bit.sic electrical part.icle has an CqlJd1 and opposite cha.rgp to a nq~(\ti\"c basic plect.rical particle, but t he mass of one chargp Illay differ from thut of the ot lwr. \Vhich of the Lwo kinds of pMtidp h(\~ t.he greater maClS ih lpft open by \Y('ber For pm-t-i('jps in thl.~ nher the same laWH of movpment us wcre deyeloped by )'·I(l'xwdl ill hi~ lrea[.j~c "On the dYll<llllical theory of guses" (1867) should "pply, ]-11] \YcLer cunbid('fed tlH', dlwJ" t.o be u dynamic mprli'lm occup.ving an infinitely largp space, in which light-wave~ could al::,o transmit them~c~lve~_ Concerning the IIledl<l.ni~m of repul~ion amongst the partirlp~, howew'l', \Veher had a diffprent opinion [Will that of l\·[axwd1.

III his work on the conselyation of energy of 1871, ]19] and ]8], \Yeber had ('Xmnilwd the laws of movement. of two basic electrica.l parti(:ips ~u bject only ~o thcir IllUtnal illtera.ction. These "IIlolecnl<lf IIIovement~", according to \Veber, re»ie;t aU experimental pxamin<ltion. ]-3pcausc of thi::" any con~ider<l.ti(lns and rcckonings can be regard0d onl.Y a~ ~cnttl.tiye.

\\'ilhdm \\'ebcr considered thik movement of two particle::, both in the din~ction of thl' straight line betweel) them and in the dirpctioll orthogonal LO it. see l7, Vol. 4, p. 268 und following] alld [S, p_ 119 and following]. Tll(c .~i7,e p, which \Yeller talle(1 a "I1lOlpcnlar di!lJen~ion" and Helmholtz the LcriUcal distance·', is here th(' declf,ivc influence. Tlw f(Jrnl1Ila for t.his ie;:

(1 j ) p=2 -+-E 0;/

Gl\Vilhelm \'\Ieber's Werke, Vol. IV, p. ;31:\91. [7, \'01. 4, pp. :\61-4J2, Ree "~p. Pl'. :):-l!) :)~Hl-

GO

/

.I

Fi~_ 2: Carl NC'UIn;uul ("LS:32 102,))

Iklll~d]('~ \lllH'II111 \lii"d,,'jJ, UN 1.-17,~<-)_ 61

In this, rand (" arc Lhe charges, 0; and c' tlw associaLed inE'rtial lIIa.<;HeH awl ('w the \Veher conHtallt. Th(" ahsolutc value of p is very sm<lll, w~vert.hcless a finite value. By IlWilns of p "molpcular movemell~s" and "Iollg-rangt' m()vcment~" are distinguishpd from O1\e another. Ovpr di.~t<lnces larger Lhan p long-range Inovenwnts occur; over di~ta.II(·eH

~hOl"t.er than p molecular mO\'eIllt'ntH t.ake plaC(~. From \Yeher's law then' follows what, seems to be a curious fad, namf'ly, tll(1t t.wo electrical particles of t.hp .~arnp ~ign b)' no mean" always repel one anotlwc hut will eW'l1 att.rae~ each other when at distances dose\" thall p. "Ve ~hall return to t.his when WE' deal with \V,~h('r's visiooUly thought~ ()]l the strudUH' of chemical <-1lUrns and rnolpcules, IJ2, pp. 211-220] <I.Ild [26. p. lG91_

The particles of Uw ether. actOl'ding to \Yeber, realize only long rangp llI()tion~: the)' can approach one another only until a diHtancp th'lt is close to p because the yalw, of tlw repabioll at p would grow t.o hlfinity. \\reber al:-;u Ip,wef' thl' ql.1CSUOn opcn. as tu whether dher parUcles are simple hagi(' ("Iectrical particles, or IIlolecule~ compri~inf', several icj(>ntical ba~ic particlc~ closely enclosed in thp molecular distance. [7, Vol. 4, p. 383].

To tn~at mat.hemat.ically the rf'puiHion of etlwr parUcles in prujectilt' lIlotion. \,V('b(~r introduced the term "elpctric ra.v~". and hp pointe(l out that when ~ueh a -'ray" r:ollided wi~h a single particlp, refipction and scaUering would occur, \VhPIl exarnining the principle", of motion of electrical partiries carrying charges of opposite polarity, \\feLl')' found lhat Iwn~ a rotational 1Il0tion of panicl("s around one anOlher call abo occur. Thus he can anually explain the exislence of Ampere'H lllolenllar currl'n~~. Such IIlolf'cular carrents may gcnerate to some t'xtent rnagndic dipoles, which imp<-lrt magnptic prop('rtics lo AubstmH:ec" [7. Vol. 4, p. 28l] and [8, p. 132]_ 'The participation of a jl<lrticlp in the motion df'pf'nds on its IlWHS. \Vhen the mass of it parUde is so large that t.he ma~s of ano(.llcr par-tid" in comparison to it, is extremely MIlall, t.hen rhe first panicle rE'mainH moti()nles~. On(' call picture Huch a particle when a bask electrical particle merges with a lllolccuk of pondprahlp l1ta~f'. Thi~ ~econd parLicle then IIl0Vek in a cirrie around lhe first. \Yith thiH r('"libatioll \Ypber had t.ran~formed Ampere's lllUlt'culal' cnrrpnt. into a pbnd-like formatio]]. \Vit.h Ampere one IIlU~t &till imaginp a singlp molecular CUlTE'nt a.s a double ClllTPnt, moviug in two circular rings around the pond("Plble nucleus. \Veher now merge~ t.ht' fir~t ring wit,1t th(' ponderable atom or molecule, and thp ~e("(md ring he confines to a singh~ parricl('. In a graphical f("pf(;~l'ntat.ion. ~he ring il.ruuIHi the planet Saturn become~ a llloon. Thus a forlllation "imilar ro Bohr's modd of the hydrogen atom was !lOW evidpnt. A lread,\, in 1862. in his Lreatise al)()ut galY'lllolllt't.ry, 143], \Yeber had t'xpl'essed in conclusion the thought that ~uch encircling particlek, moving in all adjacent &tratmn of diP ether, will give rise to light waves, atld could gt'lleratp fn-'ql.WIH:ips matching the rotations of the partidps, 17 Vol. 4, pp. 93-961_

To be precisf'. the~f' itipa.<., of \V(~h(~r reach bock to l846, when hp took is~ue with Fa­raday's concf'pt rhat til(" pt.lH"r was a media~ing llwciium awl also indeed with Faraday'~ di~coycr.Y of 18-15 of the magnetic rotation of t.he plane of polari~<'Ltion of light, [6, pp. 213 214 of \\!eller's Wrrke]. 011e should not fed Hurpris("d th,lt VVilhC'lm \Yeoer eOW'prnp(\ himself in thp 1870's with problems of the pt her, pven though his ba~ie ~hinkillg COllCprne(\ adion at a. distancp forces. Consider [.]le trend of rPhParch in phy~ics at. ~ha~ Lime. A grt'at expe.cla~ion was p!<u:pd on a Illf'xhanical etlier, which would be the key to lln(it'rst<wliing lllOf'L pprhaps e,-en aiL physical phenOllH~na. Idea.5 such as the imp(mdt-'rahl{-" awl _~jl(~ci­al fluids bl1Ch a~ the ligill-s~u£f, lwat-sullHra!lce and thl.' magndic- fluids were all thrown a.,;idp. Tll("re only H'mained Ute eiectric<'L1 fluids, rt'gardpd, hOWl'Vl'r, by llJatly phYkiciHtS <1" Huperfiuolls hypot.h('sps_ Even ~he idea of powlerahle atolll~ and mok("ule~ wa~ inh'rpretpd b~' \,\rilliam Tholil~on as molecular vort.in'~_ In the 1860's ::-'faxwdl had cn~,tr('d wit-I! I!i~

elenromagndic theory of light tht' pict.urp of an el,\I;t,ic dher in whi('h. llOwt'v,~r, ('yen tlw

62

hmall-~i/ed ('rl1('r pal'tides rotat.ed, \\-'. C. Ilankd wanted to Lransfer tllt~ plectrical pheno­mena t.o the ether. ,md Erik Edlund dPyploped in 1872 an ptht'T theory of dpctricity. In COlltra~t. to ill! this, \Yilhf'hn \!I,leber stood firm on lhe acceptance of Lwo kindh of electrical ('ntiti("~ with atomic HtrnctUfe, and (Ill chemical atom~ and moleeules wen" to be based on t.ht'~(, (for rderenceh about t.IH" ether theor.v of (,!('ctricity, see 118, p. 921]).

J. K_ F_ Ziillner had sLak<i in hiH "Princip10~ of ,'In elf'ctlOdyl1amic ducory of matt.pr" (Lrip?:ig, 1870), 1,141, th(l,t all ponderable partideh were based Holel), on l,he two kind~ uf bask ekctri('al particle~ aln;ady described_ One yPaJ' lat.er hl" wrot.e a trf'alisc abom, r,he derivation of r-,-""vtOIl 's gr(lvitational law from the statie adion of eiectl'icit:v-, 11[,,)]. Already in 187G he had the idea thaL gqYitation IIlig-hL b(' due to electrical forceh. Thereafter, howp,-(,f, hc had to ,",dmiL that the Italian astronOIllf'L Ottaviano Fabri?:io :V[osotti (1791 18(3) had prpviously had rhl' Holme ieiea in mind, [45, 1>p. -12·1 and 429], 140J and [47]. \Vilhclm \Veeber r",fer 00 thiH in the third quot(l,tion WP had comm("nted OIl, Whe)l dealing with t.he f(Jl"(:es of repuiHion bet,wcen ga~ particles. These forceH arisp when t,he (nellual) ga~ panide~ iJl th("ir projel'lile motion draw ncar to molecular diskulCes_

ZiilhH'r cOilHide("ed two Hilllple ponderable IIlolecules which an" formed from thp hasic ('lpctri("al pankkH, rphlH'ctivcly +('1 (l,nd -ej. and +('2 and -f:~. Aceording to Coulumb's law, Ihcre are rhe l''''pltlsive forc,,~ (+f'l)(+C~) and (-el)(-e2). and thp fOl'ces of a~~ritction (+f'J)(-r2) and (-f'1)(+('2) Previously iL lJad bepn accepted that tlH~ repul~ive force IWt'\-vc'l'll t.wo equal basic particips is equal to the forcp of al~ranion l)etwpen oppositdy eharg(-'(l ba.~ie parUcks. Ziillner now maint(lined that lhere was a tiny diiTen'l1C(' hetwePII tlu'H(' forcp~: lhe forC(" of attraction was ver.Y hlightly greater than thp force of H"puiHion. The diff"t>rcllce b HO kmall that il cannor IH' detected experimentally. In ~hi~ diff'erencf', however, Ziillner saw t.hp SOlll'Ce of gravitation between the two pOllderablc' panicles. Cravitation, tlif'n, is a n'~ultant. a residue of electrostalic for('Ps. AH the basic d("ctri(:al pa.rticles also p(lSH("~H a mechanically inprtia.1 mass, this rehidual force is also propurtional to th" product of thp lllasse~, and illver~ely proportioIl<l1 to the square of the disl,ann" between the two ponderablf' nlOkcule~, "IH Newton's law of p,ravitation requin'H. One should note accordingly that illnlial and p,ravitational mas~eH are propoltional to one another.

\Vilhrlm \-Vdler already states, in the third quotation that when two ~Udl ponderable pa.rlick~ an" in projectile motion Illoving like ga!-' particles and approhth one another, a repulsiw force arises. Thie; iH HllOwn in marhl'mhtical tPrlllS in the t.re'ltise from which the fift.h quoration is Lilken. Thi~ trpalise ie; thee hl.',t one in ~he serieH of "Elecl.rodynamic nlpa~ureIllenls-'

\\,ilhplm \Veber cleducp~ the residual force of artraetion of the two simple ponderablp mO\(C!(1llph situa~cd at il. di~taIlce r from one Ilnother, but nl1h'it do so in an:oniancp with his ha~ic law of pleet-rical action, [48, pp. ·18l-4831. The eii"tanee betwe(en tllf' two ba.sic ejpctricul part.ideH within l,ll(' ponderable moleeules iH a~HllIned to be infinitesimally small in COlllpariHon t.() 'I'. Following Ziilln€r, l~15J. '\Veber (lSSUIiles that, all pomler<lble Illolccul(,,~ are compoH('d of Hn ('qual amount of posiUvc and lIegativp charges. If the elementa)".\' dwrgeH are +r: alUl -I', the simpleC't ponderable> molecule would be compoHed of these two chargeH t.ogether \'V('b('r f('prpsents ~he ilwrtial mass of +e hy e ami the inertial maSh of -e by ae, ",Iwre a is ,nl llUlllPrical cOl'fficient (\Vpl)er doce; not. impose Lhat both elementary chargeH lllllht have th(, H<tIlle mass, lhat. iH, he does nOl impoHe that (! = 1, mentioning that [u~ure res('d.rch nm lead to ~hf: ddermination of th(' yahw uf their rnaSS("H). HI' th"'n aS5UllWS with Ziilhwr Lhat, the attraction bet.wP('n oppusite charges +.0 and -e is (1 +0:) timeh p,I'eateI ~hall the repulsion bet\\-(een +p and +c (or bet.-ween -e and -f), '''fhere 0: ie; a numerical faewr to be del,eflllinpd by this derivation of t.he grayj~ational force fwm pure r>iecuomagnclic forn'. ltili?:iilg these ~wo ~upp()Hitions he cairulOlteh till' elE'cLromagm'tic force bdwpell t.wo

63

pondcrable mulf'cule"" that. i~, t.he sum of twu aTtr<-l(:Tion~ and l,\iO wpuiHion~ hetwp(~n lhe dlargek +(' and -e of one molecule, and t.he charges +e and _(0 of t.hc other IlJoh"cnle. The net re~l.1lt (assuming his fimdarnent.alla.w t.o be at work here) ie; given by, ]48, p. 48:11:

" ( I (eJ")" 2,· d'c) -20'--;;- 1- -,- - + -,---, r- cIV dt elY dt

Thi~ would be the equivalent to a gravitational attractioll bClwccn the nlOle("uleH, derived only frum cicelromagnetic f(Jr(:('~. \.\'hcl\ Llw powlf'rable parridp~ come into \'ery close proximiTy, repllbi\"c forces arise, which carl be formally estimated in a.ccordancc with the laws a.irf'ady developed for (,he two ba .. ,;ic partich .. ~, [7, Vol. '1, pp. :385 and 3891, giving t.he ree;uliant. valuf' p for the molecular siLeo The forrnul<l previously given for p Iwd silllply to he lllo<iifh"d in order lO obtain tht'se mulecular distancek, which wr~ will cdll p'. \V{' ne(,d only to lIlultiply p hy thc facior 2n awl Huhstit.ute to 1/ ill{' valut' !LeT

Thh force of repuiHioll, ari~ing from Zimller'H law uf gr<lvitation alld by \Vel)(~r\ [av,', made, according to \Vilhelrn \Vpber, the acceptance of a particular H'jJuisive force lwt.wP('JI gaH I1Iolecnlek kupertluolls. August Karl Kronig (1822 1,IJ71), in hiH basic kindic theory of gascs, had treatpd gas-at.oms a.o. solid, completely clasiic sphere~. So aiHo did Rudolf Clausius, who cOIltinued Kronig's \wJrk. III "1860 \laxwell imned to t.hik area of st.udy. His dTorls lllla.ily helped t.o e~tablish the kiIlt'lic (or d.Yndmic) theory of gasps. In hb tr",atiKe of 1860 (published in lS67), ref('rred (.0 b~, \Vilhellil \-Vdwr, alld ('nlii.le(1 "On th", dYllamic<l1 t.heor)' of gases", [41], hp supposcd a repuiHive force betwecn gas IlIol{'('nle~ inYf~r~f'ly propurt.iunal to lhe fifth power of t.he di~tance lJPtwe{'n tiH'llJ, SP(' <ll~o 1-19, p. [lenJ.

III f(~viewing the dr"velopments and results rnelltiollerl alrt'ady, wc havc limitt'd onrsdv('~ [.0 the CClHe of the f'imples[. pondf'I"ahle Hlolt'C1Jic. Gas-molecule~ are for til(' most pan more complex in ("()ll~tructiOIl - according to Ziillner they cOIlsist of +nf: and -He ua~ic

E'1f'ctri!:al partid(~~, n being the IIIlIniwr of charges of OIle sign. The previ()u~ thoughl~ ahout gravi[.ation <Uld repulsive for("(~~ 0\"('1' molecular di~tanc(~k can apply without. complicatio)] to Illoh"cules of thi~ kind. \VdJer iIldic<l.te~ this towards the end of t.h(' fifth l'xiract..

l\-Ieniioning Ilf is not all that can 1)(' sail] aiHmt. the ~tructure of till' pOlJ(leI"<ll)le TllOlecuk aboul dWIllical atom» <lnd molecules ill geIl('raL III \'Ileber's opinion, th(' structure of

such a molecule is iudeed much more complex. Lel IlS now briefly e;ummarize his yiHionary lilOughtH on the illlwr ~lructure uf powl("rable moiceuiE's. Tht'y an" t.o tl(' fuund in [48J, publikhed ill hie; poe;thUlllOUS workh ill 1894.

In lhe powlerabl(" mulecUle with +'IIf' awl -It/' basic eleclrical particles, the' bask part.ides arc al wa,vs separated from one anoihcr, ami occupy it ("(~rtain space through tlH"ir roiation", awl vibritt.iun~. The hydrogen atom with n = 1 is for \Veber tbe mo~t simpl,:'

corL~tru('t.pd a.tom. He gaYe it t.he ~'ymbol [ ~ ~ ]. The two particles rolate anl1lwl OIH"

another. Basic particieH of one ~ign C<Ul be encloket\ wit-hin t.ilc close cOllfin{'~ of ,] splwre wit.h

diamct.er p. The original n"pubive forep is hen" changed to a fOH'e of artractioll. The paTtide~ ('Xl'CUle a vibrational mot.ion against one anot.her. In this insirulC(' \Ve1wr talks of an iIl»ep<-1falJit' group or partides, forminp; a wurld or lheir U""ll. Such groups call coo~i~t. of posilive and nt'p;at.ive ba~ic parlide~. Rot.<ltional motion can occur iwtwt'Pli iTldividual positive and llegativ(" ~ingl(~ particles, or 1)etw(~('n groups of partidt'h. Accordillg to [.he

{i4

t ig. 3: .lallH'S Clc'rk J\TaxwdJ (lR:H 1879)

('alllplwll, I. ~JLd \'V (;,mwH: Thl' I.ir(' or .Le1. :-'!a...<:well wil"il ~d\'Cl.iOIl~ [rom hi~ ('orr('~puTl(k"rr and ()end,iomol WliliTll',s. :-lpw editioll. l.()"dn" ISPA,

65

number'll there will be several po~~ib1c ways of constructing a ponder<lbl(" Illol('cule. A~ the number n incH:a.'le~, ~o abo will the number of po~~ibk ways incr(,H.,>e: For'll, = 2, th!:,H' are four possibilities, namely:

[ ~: 1 [~; 1 [~: 1 [~11 for greater Il let us seled just one of the many po~~ibilit.ie~, namel:-" with Lite 'Ii positive

unitips togdher and n s8paratE' negatiye unities:

-i-Il

-1

-1

Here one is reminded of the atomic model of Bohr and Soullllt'rfeld, If we ,lH(Tilw a very large inerUal mass to a positive" ha..,ic p<lrtirie, +nc, we have then the atoIlli(, nud!:'uH, TIl(' 7! negatiV(~ partklc~ -c with their yt'ry IlIuch sm<llier milS~ now rolaL('~ round tilt' heavy IlUdeUH. A pill"tide such il~ the neulron was not known to \Veber.

4 Fourth Quotation The fourth quotation appear~ in a joint paper by \V. \Veher and F Zollner, 17, Vol. /1. pp. 420 476]. It wa~ published in 1880 and is the la~t pappr publi~lwd by \\-'eber during hiH life. The motivarion to cooperar.e was lo establish a practical value for t1w ab~olute unit of re~i~t.an('e, the Ohm. Tllt'y distusH rhe ahsolnte ~y~r,em for magnetic- and ('lectroma.gnetic unitip.~ int.roduced by Gauss and \Veber, concentrilting on the absolu~e unit for elN·trical resi~tance. \Veber had presented four different practical methods for reducing the unit of rt'sistance to <:tL~oJutc~ measures. Due to the pnu:tic<ll and scientific impOltancC' of thi~ topic, UtE' British Association for the" Advancemcll~ of Science (BAAS) cre<:tr("d ill 1862 a CommiUee coordinated b.v Vi'illiam Th()m~on t.o ddiberat8 aLout it. To produC(· a ~t<lndard resbtance ddcfmined in absolute rnea~ur!:' they cho~e in essence \",r"ber's fourth metluHL Thpir task was to establish a standard value f(}r rp~istance which would have a pr<-1t"tical application. They dpcidcd in fa\'oUi of \\TeLer's electromagnetic syst.pm. The Conullission was mentioIlt'd iIi a footnote h.Y \Veber, being j\,Iaxwell one of its IIleIllber.~, [7, Vol. 4, pp. ·'120- ,17G, se(' ('sp. p. 426], our tran.~lation:

AbouL UlC mcmber~ of the Committee reported the Repo'rt, p. Ill, literally: "Thp ComIllitt(~e con~i~ts of - Professor \Vhearstoue, Prof(·~sor \Villialll~on, l\lr. C. F. Varley, Professor Thomson, Mr. Balf(mr Sklvart, I\-fr. C. W. Siem811s, Dr. A. :\fatthipssen, Professor 11axwdl, Professor Miller, Dr. .}ouh·, J\.lr. Fleeming Jenkin, Dr. EsselLach, Sir C. Bright."

A general discussion of tIlt' formatioIl ilud re~ult~ obtained by lhis COIllIllitt(' Ull plectrical ~tandard~ can be found in ]50, pp. 687 698]. Some information about. I·he IIleml)(>r~ of thi~ Committee: Charles \Vheatston(' (liW2 1875), for il, short time profC'ssor of (·X'[WrilIH'ntal physics at King'H College" in LondOll, was a distinguished invemor of apparatus ,mo nW,,$lJ­

ring ins~ruments for U{~tollsticH, optic~ and electrichy_ He constructed ~eyt'ral inHtrumentH

66

for tdl'gr<l,phy and Wi)." an PMly advocat.e for th,,' ins~allm("nt of submarine cableb_ Alexan­,]Pr \Villiams \VillialllHon (1824 19(4). profes~or of dlf'misLry at. t.he Universit.y College in Loudon, worked in t.he area of r~lpctf()lysis. about diaI!lagncti~m and its meanin:',. Cromwcll F'1('etwood V'lrlp.y (1828---1883). ingeniom Engli~h electrician. Silllultancou~I'y with \V. von Si('men~ Iw di:-;covcrcd the" ~plf-regulat.ion of a dynam.ical machine.

\Villiaill Thom~on (Lord I\elvin), (182·!--1907), famous I3riti~h ~("ientist which develo­Iwd fundam('ntal works in the areas of eiedrolll;)gne(,ism <tnd thel'Illodynamics, Exccllcnt ilio:',raphieaJ worh with many relev;)nt rcference~ carl be found in 151J and J5U]. Balfour Sb~warL (1828 IStH), ~eacher at the Seotti!;h OWE'ns College, conductcd rd("vant prepara­tory work for thr' Kirchhoff's law of ahsorption and ellliH~ion of ~pedraJ lincs. (k'tlt. with <lll natural plwnOinena from the point of view of the energy prilH:iple and W<lS rhe first ~o n'("ognize t.hc cOnIwction bdween the solar' radi<l,tion arid ~he variations in t-lw t,('ffestl'ial magu('Lism. Carl \Vilhrlm (Willialll) Siemen", (182:i 1883), physici"t, E'nginl'pr and l)rother of \-\/prner VOIl Siemens, (Iireded th(" London branch of the compan~' Siemens & HalHke. \V. von SiE'men~ ~ugw"sted in 1860 pllre mercury a~ a standard mca~llre of resistann". Au­gustll~ :'vlatthic~~en (lS:il 1870), profe"sol' of c\Jemif'Uy at St. lvhlr\-"s Ho"pital in London, O('('upicd hilll~elf especial1~' with t.hE'l'IllOelcctricity, the conductivity of Illrrab ami their va­riat.ioll~, (lml with the production of stand<lrd resistance~ obt<lined from appropriate met<lls and alloys, \Villiam Ha.1l0V'fE'S :\-liller (1801 1880), profe",sOl' of mineralogy iIi Cambridge, intrOllnced Ilolatiom; awl symbols in cristallogr<lphy which ar'c utilized e,-en today. He was a membcr of the intel'nalionalmeuic commis~ion. JamE'o; Pn~!;cotr Joule (1818 -1889), dist'oYE'l'ed t.ll(~ law of heat di~sipatioIl, ('stimaT("d PXPE'rimcntally t.hE' meehanic(ll hent equi­vuknt and discovcred t.o:',etllf'l' willl \V. ThoIllson ~hp dIed which carries their nam('s, which b utilized in ~hc liquefaction of g<lSC",. Henry Charie" Fleellling J(~nkin (Hl33-1883), l-'rofp~sor ar thE' Universit.y Colkgc in London. In an (lrtide of IS6!!, [52], he gaVe' lJlitially an oyerview about r he historical (leYE'lopment of the ('OIlCCpt of "resistancE"', br;ginning with a work of HUlllphry Da\")' of 1821. Bcyond Jacobi's etalon, he mentioned aiHo the t,r-iats of ot.her phy~icists to crcate' (I f'r,andar-d for H,,,istarlce. \Vith t.h(" installaUon of t.elE'graphic condu("fors ami submarine cables arose ;lIl urgent necessiTy to create <l st.andard !l)eu~ure of f('Si~ta.IICE'. \"-.'ith the rE'commendation of \V Thomson a Commi~sion was appointed in 1861 by ~hc 13rit.i~h Assodatiorl for tlt(' Adyancement of Sdenu", which decided filr the ilhsolute circtTollla.gnetie system of mea~ures (:l"e<lteri hv \Veber. Tlt(' experimentf' werc Iwrfonlled by Jenkin Ulili:oing ill~trUlllellt~ (lccof(ling to \V. Thom"on and .J. C. MaxwC'lL Dd,aiik can bE' round in the Rcport~ of tllE' l\Icetings of the BriUsh Association for diP ~·ear~ 1862, 1863 and 1864. In ,t letter of 25Lh l\-lay, 186·'), scnt Jenkin to \Vilhdm Weber a "tand,ml resist.ance, exhibiLing 1,/10 of the Briti~h'~ Ohm (Ohm""I), [42. p. 104]. £rnHt Es..~elba('h (1832 18(4), s~udipd with \V \Vl.~hpr ami H. yon Hdmhoitz. lIe wa . .., eHlployed by Siellwn~ in London, I(lsrly as "Cllicf Superintendcnt" by the installation of the tekgr<lph 1.0 India. Ht" died durin:', a trip by ship_ Charles Bright" gave a proccdurp of how wc cOlJld find ddpcb in a IOllg conductor wire (to look for th(_~ ~o called -'[ault~") and patcnted t.hi", tlwt.hod in 18!!2. For hi~ connection with the Committe!', see 15U, pp. 668-669 and 687].

Tllb CmIlmiHsion exerred an authoritaTive infiuence on the "Commitkp for thE' Sclrc­Lion and Nomendature of Dynamical and Electrical Cnits", set up some ten yE'ars later to promote tilE' development of electric(ll units, and to choosE' E'lfective f'yHt!'IllS of mea~ure­Ilwnt. At their "Electrica.l Congf(~ss" in Par-is (1881). there followPd the E'stabli:;hllH"nt of practical dectrical units, baHed on (.1)(' ah",olnrE' E'iectrom(lgnetic s:>'-s~eJl1 of measurement. OUf modern Internation(ll S.ystem of 'Cnit" :\IKSA is deriwd lllt,imatdy from thesc unit".

Th(~ Commission of the British ;\S50ciation adopted, however, as a basis, not only t.he electromagnetic sysrE'Ill of UlC'<ll-'urem<cnt; it also {"ho~e for practical inve~tigation (I, method

67

Fig. ,1:

William Th()lII~(lil (Lord Kl,h'in) (l80-l 19(1)

TI,()ml'~'"'' :-;ilv".",,~: ·I·h,· I.il",· "I \Villiil,lrL l'hoJJl",''', 11,1)0[[ I("]"il] of 1.,tI).',N. :] \'ob. 1.olHioll i!IIO. \'01. 1, 1', ,"):\,"),

of \Vilhdm \V(,ber'H, Wllich Thomsoll improY('("i. Thi~ method, or pro('etlurC', \<ia~ h;ised 011 [lw"iwilld.ioll inclinatOl'iulll", which \\-'eber cons~nKtpd in 18:'$7 [33[ <lnti [lB, p. 1l3[. It lia(1 mi)!;inall\' ue('n devised for lll('asurill)!; the indin<ltioll of the e<lrt.h'~ magnetic field. In t.lH' apparatlJS llH(~d I)y Thomson <l self-con~aiJl(~d coil is turncd at constant spC'cd around a yutica! axiH l)y a ~ySI,C'm of gearing'. A ~ this procee(b, the hori7.ontal illtensi~.v of f(~rreht.rial llIaglldism lm~ an inouct.ive effc,ct Tlw indllced ('UI)'C')l( ddlects a small magnet hallging cPlltr<llly in tlw ("oii. Essential to the calculation of the ('oil's r('~i~tall(:e is a knowl(,dge of rhe hori7.o11tal intenHily Tn the electromagnetic ~y;,tem of measnrement, H'~i~taTlc(, is lllea~llred in terms of Hpec(L To interpret this, thr~ ~peed of IO~atiO)l of a particle in the llltaling ("oil 'I'!;-)." taken int.o cOIl;,idera(,ion.

The llndertaking of [.lw British A~~ociation to (Teate definilion~ for the <lbsoiutr; Ohm and for srandard resistaIlce did not meet. with complete su("(:e~~. In the tables of m(~a~u­rpmen(,s, the individual values Yal'ipd [,00 largp a pen:(>ntage, acconling to \Villwlm YVeiwr awl f'ripdl'ich Kohlrau;,("h (son of [{udolf Kohlrau~ch. <lml a pupil of \Vd)("r's. [40, VoL 2, JJJJ.72 7--t[), [3t[. Weber ami Zollner ttl('refore ~ook up th" t<lbk again, hopin~ t.o estaLlish, by IlleaIl~ of alloth("r method (thc' first of \Veber'~ four IlIethod~) a more exact yallie for stalldard f(~sistaIl('e. In th(' following ~count of the procedure W(" lOuch upon the proble­maLic na.tUl'e of IlIea~uring absolute resistan("e.

i\-J()fit~ Hermann von .hwobi (1801 1874), who developed (>lectro~'yping - he was bro­tlwr t.o a well-knO'wII Ilw(.])('mat.ician. K,u'l Gust<lV .}acol)i - believed in IB46 thal Ill' h;v:l (liscovcred il ~t<mdard measurelllellt for re~i~W,nce, by producing a copper wire embeddpd in ma~tic O<'J.cobi's (,t'<lIon). To \\,iihclm \Vdwc however, t.hik was I10t an ahsolme measurC' i)) the HeIl~e of Gauss' (lefinitioll. The reasoll wa~ that in t.his clelinit.ion was included a sp('cial con~tanl of dw mat(>rial, nanwly. the ;,p(>dflc re~istanc" of copper. Thus it became eyi(kn(, (,har an alreraLioll in the iIlIJ('r s~ruct.Uf(· of the wire would ("hange its resist,ancp. An ,trbitrary ("ons~ant would also alTl'ct the definition of Ohm'"- law. \Veher ddined resi­Hta!l(,C a~ tU(" qllotien~ of d('(;t.rOIllotive force and ('llTren~, [551, [56[ awl 1,12. pp. 91 92J. Thi~ dpIlHllIded, howeV(~r, that pred~e unitH of IlIea~urelllent, be eHtahli~hcd for electl'omo­t.iH' force and cunent. For the emit of (>leClromagnetic cunen(, thi~ h<ld beell a('hieV(~d in 1841 1812 with the so-called t.angent galvaoomrtpr, a dpyicC' for m(><lHuriug the effed. of electrical Cl.lrn'nt on Illagneti~ed needle~, [57[ and [58[. The uilit for elect.romagnetic force wa~ d('fined by '\Vclwr in IB51-1852. whpn he Htudied inductioll in a geOlll'l.gneti(" field, [55, p. 277J and 156. pp. 321 and 361 363] \,,reber and ZiillIler u;;e(\ in th('ir project ~\\'o

la.rge ('oil~, with Illultipk windings of coppel wire. In one coil. rotating ill til(' tern,~trial magllC'Uc fi('ld, a ~urge of current. iH illCluccd; in the othpr coil it magnet fixed in thl' cen­tre i~ deflpctpd from i~~ Korth-South dire('t.ion by rhe effcc~ of the cUlTellt-surge. Ak th" hori;wntal ("omponent. of dw lIlagnNk fidd ve("tor i~ ~tive hoth during ~lw inductioll and alHo durillg the m("lHlll'elllent of the currellt-:'-urge, it is not cLt all nece~~ary to illdude t,he dectroIllotivc forn' ill til(' fonml1a for ("aiculaLing the re~i;,t,mlCC'.

Ullfort.unatel~' iL enWfgt"d that in ~hc' pl,u:e chosen for setting up thE' l\\'O mils (at. t.he 1'1('iskenbnrg in i.-eip7.ig), the tempPfaturp did not. remain HufficiE'ntly constaIlt, Thus tlw pn~ci~(' IIl"a~uring th'lt W<l" sough~ COl.l1d not be achieH~d. GUktav \Viedemann repf'uted ~h(' ,tttempt ten yearH later, uf>ing Llw sa.me appara~us. ,tlld readwd a satisf,l{:tory conclusion. lIe illlpnwed part~ or the equipment aM] alHo found a more suitablp location, [59[.

Th(' (Tf'ation of a more eXi\('t yaiue for ~tandarcl resi~t<:lnre held thl' att.ention or nu­llWf()llS ph}'sids~~ from various countri("s, eyen anc)' thl' P<lrik Congre~~. '\"r"w and varied lllethods \V\'f(' d('vi:-,elL [18, pp. 64:1 7 U[.

5 Conclusion \Vhilp interpreting and cOIllmenting on thp excerpts from \Veber's writings, we have takpn the opportunity ~o preHent some major point}; of interest. in the diffprent interpretations of clectJicity adopted by ~wo great scientific researchers of the nineteenth centur.Y. Fl'OIll J\'Iaxwell WE' have hi~ action by contact (field thE'ory), the finite limit to the ~pl'l'd of propagation of d(xtric and magnetic effects, ideas of continuum, and the rejection of electrical substancet>. From \Veher the anion at a distance, forces which depend also OIl ,celocity and accC'ieration of thc intE'factillg bodics, as well a.'> the acceptance of two kinds of basic electrical aloillic particles. Con};iderable parts and features of \Yeber'k collected writing"}; are to be found eyen t.oday ill Lhe btudies of elecLricity and its applications. To khow tha~ his point.s of yiew were nOT the las~ word in this area of knowledge, one might rememhpr VVebu's conclusion of his treatise on 1846. lIe writes that should new revplations follow from further s~t\(\y of Faraday's discovery of ~he influence of clecLric currents on the oscillations of ligill. then hi~ force law which had been expresked withou~ relation t.o an intervening medium (ether) might be expressed in a new form depending on lhis intermediar.y medium, [7, Vol. 4, p. 214J. And :\laxwell says in the Preface of hiH "Trr~atise" ~hat he wouk! take lhe part of an advocate (pre~enting and defending his views and those of Faraday), in~tl'ad of that of a judge. That i~, hc exemplified one mdhod inHtead of at.tempting to givp an impartial dekcriptioJl of both, I,'), p. xiI. These art' snrely thc hallmarks of ppnuine scientific re.~('a.rch.

Acknowledgments:

OIl(-~ of tIle authun, (AKTA) \\iishes to thank the Alexander von Humboldt Foullriation or Gprmany for a resemch fellov.rship during whid, this work wa~ accomplished. The a.uth()r~ thank Dr.B. Golyba.'ih for calling their at.tention to the third quotation discussed IIPre.

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[6J \Veber, \:V .. Elektrodynantische )'.I,w.ssbest.iulIIl1mgpn - -tiber ein allgellleilws Grundg('­sl'lz del" elelnrisrhcn \Vir-kung. Abha,ndlungen bf:'i Begnindllng der' Kihr:igl. Sachs_ G(­"ell.~r:hajt dcY' Wi8,w:ns(:hajten am Tage du zwcihundcr·tjiihngen GcbutlstaY/f"tf'r' Lei/i­njun"s hero,usgcgcbcrt von tier Fiir.91L .JuiJlon()w.li-.;i.lr.hcn Gesdlsr:haft. Lcip;"ig IB4fi,

70

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An~chrift. der Verfas~cr:

Andre Koch Torres Assis Instituto de Fisica 'Gleb Wataghin', Universidade Estadual de Campinas - UnicaIllp, 13083-970 CampinaH, Sao Pa.ulo, 1:lra~il e--mail: assis©ifi.unicamp.br

Karl Heimieh vViederkehr Birkcnau 24 D-22087 Hamburg, Germany

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