IN COLLABORATION WITH

THOMAS D. COPE, Ph.D. (Pennsylvania)
ASSISTANT PROFESSOR OF PHYSICS, UNIVERSITY
OF PENNSYLVANIA

BASED UPON
PRINCIPLES OF PHYSICS
BY
TOWER, SMITH and TURTON

WITH 7 PLATES AND 448 OTHER ILLUSTRATIONS

PHILADELPHIA
P. BLAKISTON'S SON & CO.
1012 WALNUT STREET


Copyright, 1920, by P. Blakiston's Son & Co.


[PREFACE]