The principal aim kept in view in the preparation of these notes has been the giving of a clear and concise presentation of the general principles which underlie electrochemical science. Endeavor has been made to meet the needs of students entering upon the study of electrochemistry and of chemists interested in the application of electrical energy to chemical problems. The literature of elect'rochemistry counts as its own a number of standard works which treat in detail the theories of the science, the methods of electrochemical analysis, and the applications of electrochemistry. Differing from these, the present notes aim merely to offer a general survey of the subject, to serve as an introduction to its study and to aid in the securing of a proper understanding and appreciation of the work along individual lines.