Preface; Advertisement; Introduction; Part I. Experiments and Observations Made in, and before the Year 1772: 1. Of fixed air; 2. Of air in which a candle, or brimstone, has burned out; 3. Of inflammable air; 4. Of air infected with animal respiration, on putrefaction; 5. Of air in which a mixture of brimstone and filings of iron has stood; 6. Of nitrous air; 7. Of air infected with the fumes of burning charcoal; 8. Of the effect of the calcination of metals; 9. Of marine acid air; 10. Miscellaneous observations; Part II. Experiments and Observations Made in the Year 1773, and the Beginning of 1774: 1. Observations on alkaline air; 2. Of common air diminished and made noxious by various processes; 3. Of nitrous air; 4. Of marine acid air; 5. Of inflammable air; 6. Of fixed air; 7. Miscellaneous experiments; 8. Queries, speculations, and hints; Appendix.