Before environmental chemistry, there were definitely observations about Earth's environment and the part chemistry played. We start with Joseph Priestley and Jan Ingenhousz's observations on how plants and animals add to or remove oxygen from the air, and exchange the oxygen with carbon dioxide, in the 1770s. We then look at Théodore de Saussure, Adolphe-Théodore Brongniart, Jacques-Joseph Ébelmen, Jean Baptiste Boussingault, Eduard Suess, and Vladimir Vernadsky's work to understand the carbon cycle. For the nitrogen cycle, we turn to Boussingault, John Bennet Lawes, Joseph Henry Gilbert, Jules Reiset, Theophile Schlœsing, Achille Müntz, Ulysse Gayon, Gabriel Dupetit, Ulysse Gayon, Gabriel Dupetit, and Engelbert Broda's research on the nitrogen cycle. (It takes a whole biosphere to understand a biosphere.) Other observations about chemistry and the environment include Robert Angus Smith and acid rain, plus the ancient-to-modern knowledge of lead poisoning.Support the show Support my podcast at https://www.patreon.com/thehistoryofchemistry Tell me how your life relates to chemistry! E-mail me at steve@historyofchem.com Get my book, O Mg! How Chemistry Came to Be, from World Scientific Publishing, https://www.worldscientific.com/worldscibooks/10.1142/12670#t=aboutBook