THE

MECHANICAL PRINCIPLES

OF

ENGINEERING

AND

ARCHITECTURE.

BY

HENRY MOSELEY, M.A. F.R.S.

CHAPLAIN IN ORDINARY TO THE QUEEN, CANON OF BRISTOL, VICAR OF OLVESTON;

CORRESPONDING MEMBER OF THE INSTITUTE OF FRANCE, AND FORMERLY PROFESSOR

OF NATURAL PHILOSOPHY AND ASTRONOMY IN KING'S COLLEGE, London.

First American from Second London Edition.

WITH ADDITIONS BY

D. H. MAHAN,
MAHAN, LL.D

U. S. MILITARY ACADEMY.

WITH ILLUSTRATIONS ON WOOD.

NEW YORK:

WILEY & HALSTED.

ENTERED according to Act of Congress, in the year 1856, by

WILEY & HALSTED,

In the Clerk's Office of the District Court of the United States, for the Southern District

of New York.

W. H. TINSON, Stereotyper.

R. CRAIGHEAD, Printer.

EDITOR'S PREFACE.

THE high place that Professor Moseley occupies in the scientific world, as an original investigator, and the clearness and elegance of the methods he has employed in this work have made it a standard text book on the subjects it treats of. In undertaking its revision for the press, at the request of the publishers of this edition, it has been deemed advisable, in view of the class of students into whose hands. it may fall, to make some slight addition to the original. This has been done in the way of Notes thrown into an Appendix, the matter of which has been gathered from various authorities; but chiefly from notes taken by the editor, whilst a pupil at the French military school at Metz, of lectures delivered by General Poncelet, at that time, 1829, professor in that school. It is a source of great pleasure to the editor to have this opportunity of publicly acknowledging his obligations to the teachings of this eminent savan, who is distinguished not more for his high scientific attainment, and the advancement he has given to mechanical science, than for having brought these to minister to the wants of the industrial classes, the intelligent success of whose operations depends so much upon mechanical science, by presenting it in a form to render it attainable by the most ordinary capacities.

The editor would remark that he has carefully refrained from making any alterations in the text revised, except corrections of typographical errors, and in one instance where, from a repetition of apparently one of these, he apprehended some difficulty might be offered to the student if allowed to remain exactly as printed in the original.

UNITED STATES MILITARY ACADEMY,

West Point March 8, 1856.