1. Analysis of Ammoniac 56 2. Specific gravity of Ammoniac 62 3. Of the quantities of true Ammoniac in Ammoniacal Solutions 65 4. Composition of Nitrate of Ammoniac 71 5. Decomposition of Carbonate of Ammoniac, by Nitrous Acid 75 6. Decomposition of Sulphate of Ammoniac by Nitre 77 7. Non-existence of Ammoniacal Nitrites 79 8. Sources of error in Analysis 80 9. Loss in Solutions of Nitrate of Ammoniac during evaporation 83 DIVISION III. DECOMPOSITION _of_ NITRATE _of_ AMMONIAC—_Preparation of_ RESPIRABLE NITROUS OXIDE. 1. Of the heat required for the decomposition of Nitrate of Ammoniac 84 2. Decomposition of Nitrate of Ammoniac—Production of respirable Nitrous Oxide—its properties 86 3. Of the Gas remaining after the absorption of Nitrous Oxide by Water 89 4. Specific Gravity of Nitrous Oxide 94 5. Analysis of Nitrous Oxide 95 6. Minute examination of the decomposition of Nitrate of Ammoniac 101 7. Of the heat produced during the decomposition of Nitrate of Ammoniac 108 8. Decomposition of Nitrate of Ammoniac at high temperatures 109 9. Speculations on the decompositions of Nitrate of Ammoniac 113 10. Of the preparation of Nitrous Oxide for experiments on respiration 117 DIVISION IV. EXPERIMENTS _and_ OBSERVATIONS _on the composition of_ NITROUS GAS, _and on its absorption by different bodies_.