Karlsruhe Congress

The Karlsruhe Congress was an international meeting of chemists organized by August Kekulé and held in Karlsruhe, Germany from 3 to 5 September 1860. It was the first international conference of chemistry, with 140 participants.

The conference is known for the adoption of atomic weights in chemistry motivated by the participation of Stanislao Cannizzaro. During the congress he showed evidence using Avogadro's hypothesis, that certain gases were not made of atoms but of diatomic molecules.

Historian Aaron J. Ihde has argued that the Karlsruhe meeting was the first international meeting of chemists and that it led to the eventual founding of the International Union of Pure and Applied Chemistry (IUPAC). (subscription required)

Organization and invitation The Karlsruhe Congress was called so that European chemists could discuss matters of chemical nomenclature, notation, and atomic weights. The organization, invitation, and sponsorship of the conference were handled by August Kekulé, Adolphe Wurtz, and Karl Weltzien. As an example of the problems facing the delegates, Kekulé's Lehrbuch der Organischen Chemie gave nineteen different formulas used by chemists for acetic acid, as shown in the figure on this page.The French chemist Auguste Laurent also listed many different contemporary representations of acetic acid (acide acétique) in his book:

An understanding was reached on the time and place of the meeting, and printing of a circular addressed to European chemists listed below, which explained the objectives and goals of an international congress was agreed upon. The circular concluded: "...with the aim of avoiding any unfortunate omissions, the undersigned request that the individuals to whom this circular will be sent please communicate it to their scientist friends who are duly authorized to attend the planned conference." The circular of the conference was sent to: +CountryCity ScientistsAustriaInnsbruckHeinrich HlasiwetzViennaAnton Schrötter von Kristelli Leopold von PebalBelgiumBrusselsJean Servais StasGhentFriedrich August Kekule von StradonitzFranceParisAnselme PayenAntoine BussyAntoine Jérôme BalardAuguste André Thomas CahoursCharles Adolphe WurtzEdmond FrémyEugéne-Melchior PéligotHenri Étienne Sainte-Claire DevilleHenri Victor RegnaultJean-Baptiste BoussingaultJean-Baptiste DumasLouis PasteurThéophile-Jules Pelouze.RennesFaustino MalagutiGermanyBerlinEilhard MitscherlichFreiburg im BreisgauLambert Henrich von BaboGiessen Hermann Franz Moritz KoppGöttingenFriedrich WöhlerHeidelbergRobert BunsenKarlsruheKarl WeltzienLeipzigOtto Linné ErdmannMunichJustus von LiebigStuttgartHermann von FehlingTübingenAdolph StreckerItalyGenovaStanislao CannizzaroTurinRaffaele PiriaRussiaKasanNikolay Nikolayevich BeketovSt. PetersburgAlexander Nikolayevich EngelhardtCarl Julius FritzscheNikolai Nikolaevich SokolovNikolay Nikolaevich ZininSwitzerlandGenevaJean Charles Galissard de MarignacZurichGeorg Andreas Karl StaedelerUnited KingdomLondonAlexander William WilliamsonAugust Wilhelm von HofmannSir Edward FranklandWilliam OdlingManchesterHenry Enfield RoscoeOxfordSir Benjamin Collins Brodie, 2nd Baronet Of the above, only 20 of 45 attended.

Meeting

First two days The congress opened in the assembly hall of the Baden Parliament on 3 September, with Weltzien serving as the general secretary. In his address, he highlighted the international and discipline-specific nature of the meeting. Kekulé delivered an opening address. Wurtz documented the proceedings for future publication. A dinner for 120 people was held in the museum hall.

The next day, the assembly, led by Weltzien, discussed the committee's proposed theme of the day before regarding the disputed meanings of "atom," "molecule," and "equivalence." However, no conclusions were reached, leading the committee to meet twice on the same day. They decided to present three specific nomenclature proposals to the assembly for further consideration.

Last day The Karlsruhe meeting started with no firm agreement on the vexing problem of atomic and molecular weights. However, on the meeting's last day reprints of Stanislao Cannizzaro's 1858 paper on atomic weights,See:

English translation: in which he utilized earlier work by Amedeo Avogadro and André-Marie Ampère, were distributed. Cannizzaro's efforts exerted a heavy and, in some cases, an almost immediate influence on the delegates. Lothar Meyer later wrote that on reading Cannizzaro's paper, (2nd edition)Cannizzaro, Stanislao (1891) with Arthur Miolati, trans., and Lothar Meyer, ed. Abriss eines Lehrganges der theoretischen Chemie [Outline of a Course of Theoretical Chemistry] (Leipzig, (Germany): Wilhelm Engelmann, 1891), p. 59. On p. 59, Lothmar Meyer wrote: "Nach Schluss der Versammlung vertheilte Freund Angelo Pavesi im Auftrage des Verfassers eine kleine ziemlich unscheinbare Schrift, den hier wiedergegeben "Sunto" etc. Cannizzaro's, der schon einige Jahre früher erschienen, aber wenig bekannt geworden war. Auch ich erhielt ein Exemplar, das ich einsteckte, um es unterwegs auf der Heimreise zu lesen. Ich las es wiederholt auch zu Hause und war erstaunt über die Klarheit, die das Schriftchen über die wichtigsten Streitpunkte verbreitete. Es fiel mir wie Schuppen von den Augen, die Zweifel schwanden, und das Gefühl ruhigster Sicherheit trat an ihre Stelle." (At the conclusion of the meeting, friend Angelo Pavesi, on behalf of the author, distributed a small, inconspicuous pamphlet, Cannizzaro's "Sunto" etc. [which is] reproduced here [Note: "Sunto" refers to: Stanislao Cannizzaro (1858) "Lettera del Prof. Stanislao Cannizzaro al Prof. S. de Luca; Sunto di un corso di filosofia chimica fatto nella Reale Università di Genova dal Professore S. Cannizzaro," Il Nuovo Cimento, 7 : 321–366.], which had appeared a few years earlier but has been little known. I too received a copy, which I pocketed to read on the way home. I also read it at home repeatedly and was amazed at the clarity that the pamphlet spread about the main issues. It was as if the scales fell from my eyes, the doubts faded, and the feeling of calmest assurance took its place.)

An important long-term result of the Karlsruhe Congress was the adoption of the now-familiar atomic weights. Prior to the Karlsruhe meeting, and going back to John Dalton's work in 1803, several systems of atomic weights were in use.An example of the confusion is provided by the table of atomic weights in the various prevailing systems, which appears in: In the tables of pages 1911–1912, Column C presents the relative atomic weights of the known elements, assigning to hydrogen (Wasserstoff) an atomic weight of 1. Column D contains the same relative atomic weights as column C, except that oxygen (Sauerstoff) is assigned a relative atomic weight of 100. (Gehler says of columns C and D: "In den Columnen C und D finden sich die Atomgewichte, wie sie sich nach den so eben entwickelten Grundsätzen als die wahrscheinlichsten ergeben möchten, … " (In columns C and D are found the atomic weights, as they would result from the principles [that have been] developed just now as the most probable ones … ) But this system assigns to oxygen an atomic weight of 8 and to carbon (Kohlenstoff) an atomic weight of 6.) Column E presents the relative atomic weights according to Berzelius, who assigned to hydrogen atoms (das Atomgewicht des einfachen Wasserstoffatoms (the atomic weight of single hydrogen atoms)) a value of 0.5 and who found oxygen to have a value of 8.01 — about 16 times greater than that of the hydrogen atom, which is correct. Column F contains the same relative atomic weights as column E, except that oxygen is assigned a relative atomic weight of 100. In one case, a value of 1 was adopted as the weight of hydrogen (the base unit), with 6 for carbon and 8 for oxygen. As long as there were uncertainties over atomic weights then the compositions of many compounds remained in doubt. Following the Karlsruhe meeting, values of about 1 for hydrogen, 12 for carbon, 16 for oxygen, and so forth were adopted. This was based on a recognition that certain elements, such as hydrogen, nitrogen, and oxygen, were composed of diatomic molecules and not individual atoms.

Attendance The number of people who wanted to participate was considerable, and on 3 September 1860, 140 chemists met together in the meeting room of the second Chamber of State, which was made available by the Frederick I, Grand Duke of Baden.

According to Wurtz, the printed list of members, supplemented by handwritten additions, contains 126 names listed below. +CountryCityScientistsAustriaInnsbruckHeinrich HlasiwetzLembergLeopold von PebalPesthTheodor WertheimViennaViktor von Lang Adolf LiebenFranz SchneiderBelgiumBrusselsJean StasGhentAugust KekuléFranceMontpellierAntoine BéchampArmand GautierC. G. ReischauerMulhouseTh. SchneiderNancyParisJean Baptiste BoussingaultJean-Baptiste DumasCharles FriedelLouis René Le Canu (1800–1871)Jean-François Persoz (1829–1908)Paul ThénardÉmile VerdetCharles-Adolphe WurtzStrasbourgEugène Théodore Jacquemin (1828–1909)Charles Oppermann (1805–1872)Frédéric Charles Schlagdenhauffen (1830–1907)Paul SchützenbergerTannAuguste Scheurer-KestnerGermanyBerlinAdolf von Baeyer Georg Hermann QuinckeBonn Hans Heinrich LandoltBreslau Lothar MeyerKassel Carl Gustav GuckelbergerKlausthal DarmstadtEmil Wilhelm WincklerErlangenEugen Freiherr von Gorup-BesanezFreiburg i. B. Lambert Heinrich von Babo Woldemar Alexander Adolph von Schneider (1843–1914)GiessenEmil BoeckmannHermann Franz Moritz Kopp GöttingenFriedrich Konrad BeilsteinHalle a. S.Wilhelm Heinrich HeintzHanover Friedrich HeerenHeidelbergBecker O. Braun Robert Bunsen Georg Ludwig Carius Richard August Carl Emil ErlenmeyerOtto MendiusJacob Heinrich Wilhelm Schiel (1813–1889)Jena Karl Gotthelf Lehmann Karlsruhe A. Klemm R. Muller Julius Neßler Karl Friedrich Heinrich Seubert (1815–1868) Karl WeltzienLeipzig Otto Linné Erdmann Wilhelm Knop KuhnMannheimCarl GundelachHeinrich G. F. SchröderMarburg a. L. Rudolf SchmittMunichFriedrich Geiger (1833–1889)Nuremberg Ernst von BibraOffenbach GrimmRappenau FinckSchönbergGustav Reinhold Hoffmann (1831–1919)SpeyerFranz KellerAlbert MühlhaüserStuttgartHermann von FehlingW. HallwachsTübingenKarl Finckh von WinterbachAlexander NaumannAdolph StreckerWiesbaden Carl Remigius Fresenius Würzburg Johann Joseph SchererValentin Schwarzenbach (1830–1890)ItalyGenoaStanislao CannizzaroPaviaAngelo PavesiMexico (1817-1880 brother of )PortugalCoimbra (1832–1910)RussiaKharkovSt. PetersburgAlexander Borodin Dmitri MendeleevNikolay ZininWarsawJakub NatansonSwedenHarpendenJoseph Henry GilbertLundNils Johan BerlinChristian Wilhelm BlomstrandStockholmSwitzerlandBernHugo SchiffGeneva Jean Charles Galissard de MarignacLausanneHenri Bischoff (1813–1889)Reichenau bei ChurZurichJohannes WislicenusSpainMadridUnited KingdomDublinJames ApjohnEdinburghAlexander Crum BrownJames Alfred WanklynFrederick GuthrieGlasgowThomas AndersonLondonBaldwin Francis Duppa (1828–1873)Carey FosterJohn Hall GladstoneHugo MüllerHenry Minchin NoadAlphonse René Le Mire de NormandyWilliam OdlingManchesterHenry Enfield RoscoeOxfordCharles Giles Bridle DaubenyGeorge GriffithFriedrich SchickendantzWoolwichFrederick Augustus Abel

References

Karlsruhe Congress

Bron en licentie