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.

It has been 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).

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.

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:

Of the above, only 20 of 45 attended.

Meeting

First two days

The congress opened in the assembly hall of the Baden Parliament the 3th 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, 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,

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. 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.

References

Further reading

* (subscription required)
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: (Note the incorrect spelling of Weltzien's name.)

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: (Originally published in 1964.)

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: (Note the incorrect month given for the conference.)

* {{cite book , title=The Question of the Atom: From the Karlsruhe Congress to the First Solvay Conference, 1860–1911 , last=Nye , first=Mary Jo , publisher=Springer , year=1984 , isbn=978-0-938228-07-3 , url-access=registration , url=https://archive.org/details/questionofatomfr0000unse

External links

''When Science Went International'', Chemical & Engineering News, Vol. 88, 3.9.2010



Cannizzaro's 1858 paper

''A History of Chemistry'' by F. J. Moore (1918) New York: McGraw-Hill

History of chemistry
Academic conferences
Event in Karlsruhe
Chemical nomenclature
Chemistry conferences
1860 in science
1860 in Baden
1860 conferences
Science events in Germany
September 1860