Spallanzani and the “Chemistry of Light”

According to Lavoisier’s chemistry, nitrogen was the inert gas par excellence. Therefore, a strong challenge was the reactive visibility that the German chemist Johann Friedrich August Göttling (1753-1809) had ascribed to it and which was refuted by the Italian biologist Lazzaro Spallanzani (1729-1799). After the first three months of his inquiry on animal respiration (1795-1799), something weird drew Spallanzani’s attention: his eudiometric analysis forced him to deal with the enigma of an increase of nitrogen during the passage of the air through the lungs. In Lavoisier’s interpretation, this fact was impossible and it was at this moment that Göttling’s name appeared in Spallanzani’s notebook. He suspended his biological inquiry to work on the reactivity of the gases: his eye was dazed by a blurring phantasmagoria of lights, fumes, and nuances of colours which supported Göttling’s thesis. Translating the “chemistry of light” into a chemistry of weight and volume was difficult and exhausting. In the end, however, Göttling’s explanations yielded one after another, and Spallanzani confirmed brilliantly the chimie nouvelle with his Chimico esame degli esperimenti del Sig. Gottling (1796).