The book has been written for college Freshmen, and, as its title implies, it is intended to serve as an introduction to general chemistry. In consequence we have aimed to present a continuous and connected story in teachable form and have not attempted to give extensive descriptive and numerical data where such matter is of little interest to the student or is not needed for the development of important principles. Inasmuch as the choice and arrangement of topics in the earlier part of this book depart noticeably from the familiar order, some explanation seems necessary. We shall therefore sketch briefly the plan of the less conventional chapters, together with the "philosophy of arrangement" which has resulted in the scheme presented. The first chapter, which is brief, deals with the measurement of gases and the gas laws. In the next five chapters the most fundamental concepts of the science of chemistry are developed. These include: indestructibility of matter, idea of a pure substance, decomposition of pure substances, elements, analysis of substances and percentage composition, the law of definite composition, derivation of formulae.