The most prominent chemist in the generation following Lavoisier was Berzelius in Sweden. Together with Gay-Lussac in Paris and Davy in London, he discovered new elements, and improved atomic weights and combustion analysis for organic compounds. Invention of electrolysis led not only to new elements but also to the theory of dualism, with elements being held together by electrostatic attraction. Wöhler's report on the synthesis of urea revealed isomerism but also persistent naiveté about treating quantitative data. In their collaborative investigation of oil of bitter almonds Wöhler and Liebig extended dualism to organic chemistry via the radical theory.