In this book an endeavour has been made to meet the demand for a concise course of practical interest and utility. The text as a whole is based on lecture notes which have been used for a considerable time in the preparation of candidates for the ordinary M.o.T. examinations in Magnetism and Deviations of the Magnetic Compass and the needs of such candidates have been kept particularly in mind in the presentation of the subject.
Very careful consideration has been given to the scope of the book which it is hoped will be sufficient to stimulate an interest in what, to date, has been looked upon by some as black magic. Emphasis has been placed on the distinction between the deviation. The special features of the book are numerous worked examples for exercise at the ends of the chapters. By means of these examples, it should be possible for the student to test his grasp of the principles and processes given in the text and later, when in a position of authority, to detect defects, if any, in the compensation of the magnetic compasses and, moreover, remedy these defects rather than tolerate an inefficient compass.