PREFACE

THAT laboratory work is an important part of a course in elementary physics is no longer open to question. The opinion. is also practically unanimous that the laboratory work should constitute an organic and integral part of the course, pursued concurrently with the instruction of the class room throughout the subject. Beyond this point, however, there is still a copsiderable diversity of opinion and practice within the limits of good teaching. While the author believes that this Manual will be found adapted to any approved plan of work, it will not be out of place to present the point of view from which the book was written.

Its scope is that of a laboratory guide for the pupil. It encroaches as little as possible on the province of the text-book, and does not include class-room experiments to be performed by the teacher. Many such experiments must be presented in any well-conducted course in physics; but it is unnecessary to place the directions for them in the hands of the pupils.

Every experiment in the course is a physical experiment. With a superabundance of excellent material within the scope of elementary physics, there would seem to be no valid reason for spending the first days in the laboratory on manipulation and measurement with vernier and micrometer calipers, the diagonal scale, the spherometer, etc., as is sometimes done, with no physics in sight.

The course aims to present a maximum of physics with a minimum of manipulation. So far as the teaching of elementary science is concerned, skill in manipulation must be regarded as a means to an end, not as an end in itself. The more simply

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