ELEMENTARY INTRODUCTION TO PRACTICAL MECHANICS ILLUSTRATED BY NUMEROUS EXAMPLES BEING THE FOURTH EDITION OF ELEMENTARY EXAMPLES IN PRACTICAL MECHANICS' BY THE REV. JOHN F. TWISDEN, M.A. PROFESSOR OF MATHEMATICS IN THE LONDON LONGMANS, GREEN, AND CO. 1870 PREFACE. THE FOLLOWING TREATISE is designed to be an Introduction to the science of Applied Mechanics: in this it differs from all the elementary works commonly in use, which are introductory to Rational Mechanics. How great a difference is caused by this circumstance will appear from an inspection of the Contents; it may, however, be mentioned that, at the least, one-half of the present work has no counterpart in any Elementary Treatise that has fallen under the author's notice: that so great a divergence from the usual type should be possible seems sufficient reason for believing that something is wanting in the ordinary works, but how far the present will supply that want is, of course, another question. It was originally intended to be a book of examples, and a supplement to others already in existence; it was, however, found that by a few additions it could be made independent, and it was thought that what was gained in point of convenience by completeness, would more than compensate a small increase of size and cost. The work is intended to comprise two courses: the first is contained in Chapter I., the first section of Chapter II. and Chapter III. of Part I. and in Chapter I. of Part II.; |