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THE STRENGTH OF MATERIALS.
WITH RULES FOR APPLICATION IN ARCHITECTURE,
THE CONSTRUCTION OF SUSPENSION BRIDGES, RAILWAYS, ETC.;
BY PETER BARLOW, F.R.S.,
MEM. INST. OF FRANCE; OF THE IMP. AND ROYAL ACADEMIES OF PETERSBURGH AND BRUSSELS;
A NEW EDITION.
REVISED BY HIS SONS,
P. W. BARLOW, F.R.S., AND W. H. BARLOW, F.R.S.,
AN ESSAY (WITH ILLUSTRATIONS) ON THE EFFECT PRODUCED BY PASSING
WEIGHTS OVER ELASTIC BARS.
BY THE REV. ROBERT WILLIS, M.A., F.R.S.
LOCKWOOD & CO., 7, STATIONERS' HALL COURT.
PREFACE TO THE PRESENT EDITION.
A FIFTH edition of Professor Barlow's very valuable work appeared in 1851. This, the Sixth edition, has been carefully corrected; and, although it is not increased in external dimensions, owing to the economy of space in printing, it has been greatly enlarged, and will be found to contain much additional interesting matter.
There have been no alterations of consequence in the first part of the treatise on the Strength of Timber. The following important and valuable additions, however, have been made to that part treating of Cast Iron (1) Experiments by Eaton Hodgkinson, Esq., on the Strength of Cast Iron of various denominations; (2) An extract from papers on the Transverse Strength of Beams, by W. H. Barlow, Esq., F.R.S., with an appendix by the late Professor Barlow; and (3) a short article on the Strength of Cast Iron Columns. From the next division of the Treatise, the description of the Proving Machine in Woolwich Dockyard, and the article on the Comparative Strength of Parallel Rails of various sections, have been omitted. There have been introduced experiments by W. Fairbairn, Esq., on Iron and Steel Plates, on the behaviour of Girders subjected to the Vibrations of a Changing Load, and on various cast and wrought iron beams; also numerous experiments by D. Kirkaldy, Esq., on wrought iron and steel bars. At the end of the volume will be found a short Appendix of formulæ for ready application in calculating bridges and girders.
An explanation is necessary for the apparent want of order in the distribution of some of the new matter that has been introduced; more especially for that of placing experiments on Cast Iron beams in the portion of the work devoted to Malleable Iron.
It was thought advisable, however, to disregard strict classification of material, in order that Mr. Fairbairn's experiments might appear together.
The entire work has been revised by Professor Barlow's sons, Peter William Barlow, Esq., F.R.S., and William Henry Barlow, Esq., F.R.S., to whom I beg to tender my sincere thanks, as also to William Fairbairn, Esq., LL.D., F.R.S., and David Kirkaldy, Esq., for their valuable assistance.
As a small tribute of respect and esteem for the late Professor, I have inserted a short memoir of his life, feeling confident that it will be received with pleasure by the members of a Profession for which he has done so much.
ABINGDON STREET, WESTMINSTER,
EXTRACT FROM AUTHOR'S PREFACE TO THE
THE first edition of my "Essay on the Strength and Stress of Timber" was published in 1817, since which it has gone through three editions: another edition having been called for, I have thought it right to remodel the whole, and to introduce into it a great variety of matter not found in the original work. At the time of the first publication, the construction of suspension bridges was in its infancy; and the application of malleable iron for the purposes of railways, unknown. These, and various novel applications of timber, iron, and other materials, to different mechanical works, have rendered it necessary to investigate experimentally and theoretically, many subjects which were not known when the first edition of this work was published, and which it was difficult to introduce without remodelling the whole. This has been accordingly done, and it is hoped that the utility of the work has been thereby greatly increased.