The reader will soon perceive, in perusing this work, that he is often supposed to have previously acquired some slight knowledge of natural philosophy, a circumstance, indeed, which appears very desirable. The author’s original intention was to commence this work by a small tract, explaining, on a plan analogous to this, the most essential rudiments of that science. This idea she has since abandoned; but the manuscript was ready, and might, perhaps, have been printed at some future period, had not an elementary work of a similar description, under the tide of “Scientific Dialogues,” been pointed out to her, which, on a rapid perusal, she thought very ingenious, and well calculated to answer its intended object. Contents Of _The First Volume_. ON SIMPLE BODIES. CONVERSATION I. Page ON THE GENERAL PRINCIPLES OF CHEMISTRY. 1 Connexion between Chemistry and Natural Philosophy. --Improved State of modern Chemistry. --Its use in the Arts. --The general Objects of Chemistry. --Definition of Elementary Bodies. --Definition of Decomposition. --Integrant and Constituent Particles. --Distinction between Simple and Compound Bodies. --Classification of Simple Bodies. --Of Chemical Affinity, or Attraction of Composition. --Examples of Composition and Decomposition. CONVERSATION II. ON LIGHT AND HEAT. 26 Light and Heat capable of being separated. --Dr. Herschel’s Experiments. --Phosphorescence. --Of Caloric. --Its two Modifications. --Free Caloric. --Of the three different States of Bodies, solid, fluid, and aeriform. --Dilatation of solid Bodies. --Pyrometer. --Dilatation of Fluids. --Thermometer. --Dilatation of Elastic Fluids. --Air Thermometer. --Equal Diffusion of Caloric. --Cold a Negative Quality. --Professor Prevost’s Theory of the Radiation of Heat. --Professor Pictet’s Experiments on the Reflexion of Heat. --Mr. Leslie’s Experiments on the Radiation of Heat. CONVERSATION III. CONTINUATION OF THE SUBJECT. 70 Of the different Power of Bodies to conduct Heat. --Attempt to account for this Power. --Count Rumford’s Theory of the non-conducting Power of Fluids. --Phenomena of Boiling. --Of Solution in general. --Solvent Power of Water. --Difference between Solution and Mixture. --Solvent Power of Caloric. --Of Clouds, Rain, Dr. Wells’ theory of Dew, Evaporation, &c. --Influence of Atmospherical Pressure on Evaporation. --Ignition. CONVERSATION IV. ON COMBINED CALORIC, COMPREHENDING SPECIFIC HEAT AND LATENT HEAT. 122