Convened by August Kekulé, Charles-Adolphe Wurtz, and Karl Weltzien, the 1860 Karlsruhe Congress brings together 127 chemists from 12 countries to discuss chemical nomenclature, formula notation, and, above all, the more than fifty years of confusion between atomic and molecular weights — to the point that 19 different formulas circulated to represent acetic acid. The congress fails to reach a formal agreement, but on the last day Stanislao Cannizzaro distributes his 1858 pamphlet, which revived Avogadro's 1811 hypothesis, among the attendees. According to a quote attributed to Julius Lothar Meyer, reading the pamphlet afterward made him feel his doubts dissolve into sudden certainty. In the following years, the atomic-weight system based on Cannizzaro and Avogadro — hydrogen=1, carbon=12, oxygen=16 — spreads and is adopted by the chemistry community, including Mendeleev and Meyer when building their periodic tables.