PREFACE.

THIS work has been written in the hope of supplying a want which I believe is very widely felt; viz. of a book which explains the elementary principles of Dynamics, illustrating them by numerous easy numerical examples in a manner suitable for use in Schools with boys of ordinary mathematical attain

ments.

I have adopted a suggestion,-due I believe to Mr Hayward, F.R.S., of Harrow School-that the first part of the book should treat exclusively of Linear· Dynamics; thus avoiding, at the beginning of the subject, all purely geometrical difficulties.

It will be found that, with the exception of one or two Articles, Sections I. and IV. (which may be read separately, and in which the fundamental Principles of Dynamics are explained) demand only a knowledge of Simple Equations in Algebra. In no case is any greater knowledge on the part of the Student assumed, than is denoted by Progressions in Algebra, the Trigonometry of one Angle, and (in Chapters IX. and X.) the Parabola.

I have ventured to suggest names for the units of velocity and acceleration, the use of which will be found to simplify considerably the language of the subject.

I should be greatly obliged to those who may make use of the book if they would point out any defects or obscurities in the text or would offer suggestions for its improvement.

GONVILLE AND CAIUS COLLEGE.

April, 1887.

J. B. LOCK.

NOTE.

The Examination Papers appended to the Book in most cases sufficiently indicate the range of the various Examinations.

The following suggestions however may be found useful. For the Dynamics of the Additional Subjects in the Previous Examination at Cambridge, the Student may confine his attention to Section I., Section II. up to the end of Art. 63, and Art. 133 of Chapter XI.

For the First M.B. Examination, in addition to the above, the Student should read Section IV.

Those sections which are marked with an asterisk may in most cases be reserved with advantage for a second reading of the subject.