OF NATURAL PHILOSOPHY BY SIR WILLIAM THOMSON, LL.D., D.C.L., F.R.S., PROFESSOR OF NATURAL PHILOSOPHY IN THE UNIVERSITY OF GLASGOW, AND PETER GUTHRIE TAIT, M.A., PROFESSOR OF NATURAL PHILOSOPHY IN THE UNIVERSITY OF EDINBURGH. PART I. LIBRARY UNIVERSITY RADCLIFF SECOND EDITION. 7 APR 79 MUSEUM Cambridge: AT THE UNIVERSITY PRESS. 1879 [All Rights reserved] PREFACE. To the first Edition of this work, published in 1872, the following statement was prefixed :— "The work consists, in great part, of the large-type, or non-mathematical, portion of our Treatise on Natural Philosophy. "As it is designed more especially for use in Schools and in the junior classes in Universities, the mathematical methods employed are, almost without exception, limited to those of the most elementary geometry, algebra, and trigonometry. Where higher methods are required for an investigation, the reader is, in general, simply referred to our larger work. "It is particularly interesting to note how many theorems, even among those not ordinarily attacked without the help of the Differential Calculus, have here been found to yield easily to geometrical methods of the most elementary cha racter. 'Simplification of modes of proof is not merely an indication of advance in our knowledge of a subject, but is also the surest guarantee of readiness for farther progress. "A large part of Chapter VII is reprinted from a series of notes of a part of the Glasgow course, drawn up for "We have had considerable difficulty in compiling this treatise from the larger work-arising from the necessity for condensation to a degree almost incompatible with the design to omit nothing of importance: and we feel that it would have given us much less trouble and anxiety, and would probably have ensured a better result, had we written the volume anew without keeping the larger book constantly before us. The sole justification of the course we have pur- sued is that wherever, in the present volume, the student may feel further information to be desirable, he will have no difficulty in finding it in the corresponding pages of the "A great portion of the present volume has been in type since the autumn of 1863, and has been printed for the use To this we would now only add that the whole has been The present edition has been carefully revised by Mr W. |