text: 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).