I. Introductory. Without pretending to have discovered the primary cause of earthquakes, the author is firmly convinced that the plan which he has been elaborating for some years -will reduce the present chaos of seismological study to some sort of order, and will enable others to go farther than he has done. This plan is made up of four parts, and the present paper, which deals with the British Empire, is a section of the third part now approaching completion.These four parts, three of which will be briefly outlined in the following pages, are :— 1. Formation of an Earthquake Catalogue. 2. Refutation of the empirical laws previously enunciated. 3. Description of the globe from the seismic point of view. 4. Study of seismic phenomena in the United Kingdom and the British Colonies. II. Formation of an Earthquake Catalogue. More than 100,000 observations of earthquakes have been brought together, 6175 of which have been made use of in the present work. These observations vary much in value ; when they are the result of isolated narratives, gathered from documents of all kinds (but the object of none of which is the special study of earthquakes), we get so-called I historical series,' generally of little account. If, on the other hand, scientific men have especially busied themselves with these phenomena in any particular country, and have taken careful note of the earthquakes felt by them or reported to them, we