A systematic investigation examines the chemical composition, production, and properties of nitrous oxide and closely related gases. Detailed experimental sections analyze nitric and nitrous acids, study ammoniac, describe methods for producing respirable nitrous oxide, and report absorption and decomposition tests with various reagents, including measurements of densities and heat effects. The author records respiration experiments on animals and humans to observe physiological effects and alterations to the gas, compares results with earlier chemists, discusses apparatus and sources of experimental error, and draws conclusions about the combinations of oxygen and nitrogen while stressing careful observation and methodological caution.