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.

SECOND EDITION.

WITH ILLUSTRATIONS

ON WOOD.

LONDON:

LONGMAN, BROWN, GREEN, AND LONGMANS.

186.a.14.

By the same Author.

ILLUSTRATIONS OF PRACTICAL MECHANICS.

LONDON:

A. and G. A. SIOTTISWOODE,.
New-street Square.

PREFACE

TO THE

SECOND EDITION.

I HAVE added in this Edition articles:-first, "On the Dynamical Stability of Floating Bodies;" secondly, "On the Rolling of a Cylinder;" thirdly, "On the descent of a body upon an inclined plane, when subjected to variations of temperature, which would otherwise rest upon it;" fourthly, "On the state bordering upon motion of a body moveable about a cylindrical axis of finite dimensions, when acted upon by any number of pressures."

The conditions of the dynamical stability of floating bodies include those of the rolling and pitching motion of ships. The discussion of the rolling motion of a cylinder includes that of the rocking motion to which a locomotive engine is subject when its driving wheels are falsely balanced, and that of the slip of the wheel due to the same cause. The descent of a body upon an inclined plane when subjected to variations in temperature, which otherwise would rest upon it, appears to explain satisfactorily the descent of glaciers.

The numerous corrections made in the text, I owe chiefly to my old pupils at King's College, to whom

the lectures of which it contains the substance, were addressed. For several important ones I am, however, indebted to Mr. Robinson, Master of the School for Shipwrights' Apprentices, in Her Majesty's Dockyard, Portsea; to whom I have also to express my warm acknowledgments for the care with which he has corrected the proof sheets whilst going through the press. May, 1855.

PREFACE.

In the following work, I have proposed to myself to apply the principles of mechanics to the discussion of the most important and obvious of those questions which present themselves in the practice of the engineer and the architect; and I have sought to include in that discussion all the circumstances on which the practical solution of such questions may be assumed to depend. It includes the substance of a course of lectures delivered to the students of King's College in the department of engineering and architecture, during the years 1840, 1841, 1842.*

In the first part I have treated of those portions of the science of STATICS, which have their application in the theory of machines and the theory of con struction.

In the second, of the science of DYNAMICS, and, under this head, particularly of that union of a con

The first 170 pages of the work were printed for the use of my pupils in the year 1840. Copies of them were about the same time in the possession of several of my friends in the Universities.