Transcriber’s Notes: Underscores “_” before and after a word or phrase indicate _italics_ in the original text. Small capitals have been converted to SOLID capitals. Illustrations have been moved so they do not break up paragraphs. Antiquated spellings have been preserved. Typographical and punctuation errors have been silently corrected. The text usually uses a comma to designate a decimal point, although a period is used in some instances. The changes mentioned in the ERRATA have been applied to the text. RESEARCHES, CHEMICAL AND PHILOSOPHICAL; CHIEFLY CONCERNING NITROUS OXIDE, OR DEPHLOGISTICATED NITROUS AIR, AND ITS RESPIRATION. By HUMPHRY DAVY, SUPERINTENDENT OF THE MEDICAL PNEUMATIC INSTITUTION. LONDON: PRINTED FOR J. JOHNSON, ST. PAUL’S CHURCH-YARD, BY BIGGS AND COTTLE, BRISTOL, 1800. CONTENTS. INTRODUCTION, xi. RESEARCH I. _Into the analysis of_ NITRIC ACID _and_ NITROUS GAS, _and the production of_ NITROUS OXIDE. DIVISION I. EXPERIMENTS _and_ OBSERVATIONS _on the composition of_ NITRIC ACID, _and on its combinations with_ WATER _and_ NITROUS GAS. 1. Preliminaries 1 2. Production of aëriform Nitrous Acid 3 3. Specific gravity of Gases 6 4. Experiment on the formation of Nitrous Acid 11 5. Conclusions 17 6. Experiments on the combination of Nitrous Gas with Nitric Acid 17 7. Additional Experiments 23 8. Conclusions 29 9. Mr. THOMSON’S Theory of the difference between Nitric and Nitrous Acid 30 10. Composition of the different Nitrous Acids 36 11. Combination of Nitric Acid with Water 38 12. Of Nitrous Vapor 42 13. Comparison of the results with those of Cavendish and Lavoisier 43 DIVISION II. EXPERIMENTS _and_ OBSERVATIONS _on the composition of_ AMMONIAC _and on its combinations with_ WATER _and_ NITRIC ACID.