The Karlsruhe Congress was an international meeting of chemists held in Karlsruhe, Germany from 3 to 5 September 1860. It was the first international conference of chemistry worldwide.
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 Karlsruhe meeting ended 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, in which he utilized earlier work by Amedeo Avogadro, 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, "The scales seemed to fall from my eyes."
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 Dalton's work in 1803, several systems of atomic weights were in use. 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.
According to Wurtz's list, the congress was attended by the scientists listed below.
- Belgium. Brussels: Stas; Ghent: Donny, A. Kekulé
- Germany. Berlin: Ad. Baeyer, G. Quinke; Bonn: H. Landolt; Breslau: Lothar Meyer; Kassel: Guckelberger,; Klausthal: Streng; Darmstadt: E. Winkler; Erlangen: v. Gorup-Besanez; Freiburg i. B.: v. Babo, Schneyder; Giessen: Boeckmann, H. Kopp, H. Will; Göttingen: F. Beilstein; Halle a. S.: W. Heintz; Hanover: Heeren; Heidelberg: Becker, O. Braun, R. Bunsen, L. Carius, E. Erlenmeyer, O. Mendius, Schiel; Jena: Lehmann, H. Ludwig; Karlsruhe: A. Klemm, R. Muller, J. Nessler, Petersen, K. Seubert, Weltzien; Leipzig: O. L. Erdmann, Hirzel, Knop, Kuhn; Mannheim: Gundelach, Schroeder; Marburg a. L.: R. Schmidt, Zwenger; Munich: Geiger; Nuremberg: v. Bibra; Offenbach: Grimm; Rappenau: Finck; Schönberg: R. Hoffmann; Speyer: Keller, Mühlhaüser; Stuttgart: v. Fehling, W. Hallwachs; Tübingen: Finckh, A. Naumann, A. Strecker; Wiesbaden: Kasselmann, R. Fresenius, C. Neubauer; Würzburg: Scherer, v. Schwarzenbach
- United Kingdom. Dublin: Apjohn A.; Edinburgh: Al. Crum Brown, Wanklyn, F. Guthrie; Glasgow: Anderson; London: B. F. Duppa, G. C. Foster, Gladstone, Müller, Noad, A. Normandy, Odling; Manchester: Roscoe; Oxford: Daubeny, G. Griffeth, F. Schickendantz; Woolwich: Abel
- France. Montpellier: A. Béchamp, A. Gautier, C. G. Reichauer; Mülhousen i. E.: Th. Schneider; Nancy: J. Nicklès; Paris: Boussingault, Dumas, C. Friedel, L. Grandeau, Le Canu, Persoz, Alf. Riche, P. Thénard, Verdét, C.-A. Wurtz; Strasbourg i. E.: Jacquemin, Oppermann, F. Schlagdenhaussen, P. Schützenberger; Tann: Ch. Kestner, Scheurer-Kestner
- Italy. Genoa: Cannizzaro; Pavia: Pavesi.
- Mexico. Posselt (Louis Posselt (1817–1880), brother of Christian Posselt)
- Austria. Innsbruck: Hlasiwetz; Lemberg: Pebal; Pesth: Th. Wertheim; Vienna: V. v. Lang, A. Lieben, Folwarezny, F. Schneider
- Portugal. Coïmbra: Mide Carvalho
- Russia. Kharkov: Sawitsch; St. Petersburg: Borodin, Mendeleev, L. Schischkoff, Zinin N.; Warsaw: T. Lesinski, J. Natanson
- Sweden. Harpenden: J. H. Gilbert; Lund: Berlin, C. W. Blomstrand; Stockholm: Bahr
- Switzerland. Bern: C. Brunner, H. Schiff; Geneva: C. Marignac; Lausanne: Bischoff; Reichenau bei Chur: A. v. Planta; Zurich: J. Wislicenus
- Spain. Madrid: R. Torres Muñoz de Luna (He was wrongly referenced in the Wurtz's list as R. de Suna or Ramón de Luna)
- Leicester, Henry M. (1956). The Historical Background of Chemistry. John Wiley and Sons. pp. 191–192. ISBN 0-486-61053-5.
- Kekulé, A. (1861). Lehrbuch der Organischen Chemie. Verlag von Ferdinand Enke. p. 58.
- Moore, F. J. (1931). A History of Chemistry. McGraw-Hill. pp. 182–1184. ISBN 0-07-148855-3. (2nd edition)
- Ihde, Aaron J. (1961). "The Karlsruhe Congress: A Centennial Retrospective". Journal of Chemical Education. 38 (2): 83–86. Bibcode:1961JChEd..38...83I. doi:10.1021/ed038p83. (subscription required)
- See Charles-Adolphe Wurtz's report on the Karlsruhe Congress. Wurtz's list had "England" instead of "United Kingdom", and Warsaw was listed with Russia.
- Pellón, Inés; Bilbao-Goyoaga, Ana (2013). "The chemical atomic theory in Ramón Torres Muñoz de Luna's textbooks (1848-1885)". Circumscribere. 13: 46–65.
- de Milt, Clara (1951). "The Congress at Karlsruhe". Journal of Chemical Education. 28 (8): 421–425. Bibcode:1951JChEd..28..421D. doi:10.1021/ed028p421. (subscription required)
- Hartley, Harold (1966). "Stanislao Cannizzaro, F.R.S. (1826 – 1910) and the First International Chemical Conference at Karlsruhe". Notes and Records of the Royal Society of London. 21 (1): 56–63. doi:10.1098/rsnr.1966.0006.
- Hudson, John (1992). The History of Chemistry. Chapman and Hall. pp. 122–125. ISBN 0-12-007208-4.
- (Note the incorrect spelling of Weltzien's name.)
- (Originally published in 1964.)
- Laing, Michael (November 1995). "The Karlsruhe Congress, 1860". Education in Chemistry: 151–153.
- Partington, J. R. (1951). A Short History of Chemistry. MacMillan and Company. pp. 256–258. ISBN 0-486-65977-1.
- (Note the incorrect month given for the conference.)
- Nye, Mary Jo (1984). The Question of the Atom: From the Karlsruhe Congress to the First Solvay Conference, 1860-1911. Springer. ISBN 0-938228-07-2.