THE aim of this class-book is to present a clear account of the essential principles and phenomena of elementary chemistry. The subject is divided into three sections. Section 1 is of an introductory nature. The earlier chapters are concerned with the study of such common substances as air, water, chalk, and the acids, bases, and salts. In the later chapters of this part, the fundamental principles and theories are deduced and outlined. This section concludes with a description of the phenomena of electrolysis and with chemical calculations. Section 2 consists of a lengthy systematic treatment of the non-metals and their more important compounds, whilst Section 3 deals similarly (but more briefly) with some of the metals.