EXPERIMENTAL MECHANICS
EXPERIMENTAL MECHANICS
A COURSE OF LECTURES
DELIVERED AT THE ROYAL COLLEGE OF SCIENCE
FOR IRELAND
BY
SIR ROBERT STAWELL BALL, LL.D., F.R.S.
ASTRONOMER ROYAL OF IRELAND
FORMERLY PROFESSOR OF APPLIED MATHEMATICS AND
MECHANISM IN THE ROYAL COLLEGE OF SCIENCE
FOR IRELAND (SCIENCE AND ART DEPARTMENT)
WITH ILLUSTRATIONS
SECOND EDITION
London
MACMILLAN AND CO.
AND NEW YORK
1888.
The Right of Translation and Reproduction is reserved
Richard Clay and Sons, Limited,
LONDON AND BUNGAY.
The First Edition was printed in 1871.
PREFACE.
I here present the revised edition of a course of lectures onExperimental Mechanics which I delivered in the Royal College ofScience at Dublin eighteen years ago. The audience was a large eveningclass consisting chiefly of artisans.
The teacher of Elementary Mechanics, whether he be in a Board School, aTechnical School, a Public School, a Science College, or a University,frequently desires to enforce his lessons by exhibiting workingapparatus to his pupils, and by making careful measurements in theirpresence.
He wants for this purpose apparatus of substantial proportionsvisible from every part of his lecture room. He wants to have it ofsuch a universal character that he can produce from it day after daycombinations of an ever-varying type. He wishes it to be composed ofwell-designed and well-made parts that shall be strong and durable, and[Pg viii]that will not easily get out of order. He wishes those parts to be suchthat even persons not specially trained in manual skill shall presentlylearn how to combine them with good effect. Lastly, he desires to economizehis money in the matters of varnish, mahogany, and glass cases.
I found that I was able to satisfy all these requirements by a suitableadaptation of the very ingenious system of mechanical apparatus devisedby the late Professor Willis of Cambridge. The elements of the system Ihave briefly described in an Appendix, and what adaptations I have madeof it are shown in almost every page and every figure of the book.
In revising the present edition I have been aided by my friends Mr. G.L. Cathcart, the Rev. M. H. Close, and Mr. E. P. Culverwell.
Observatory, Co. Dublin,
3rd August, 1888.