The primary aim of the present book is to supply for students
beginning the study of Theoretical Mechanics a course of such a
nature as shall emphasize the fundamental physical principles of
the subject. .Different students will of course approach the study
of mechanics with different interests, different aims, and different
amounts of mathematical equipment, so that it may not be possible
to produce a single book which shall exactly fit the requirements
of every class of student. But I believe that all students of me-
mechanics, no matter what their aims and intentions may be, will
be in the same position in one respect, namely that they will best
begin the study of the subject by trying to acquire a firm grasp
of the physical principles, leaving aside at first all mathematical
developments and all practical applications, except in so far as these
contribute to the elucidation of the fundamental physical principles.
belief is held all