THE NC-4

This historic airplane, the Navy-Curtiss No. 4 (known as the NC-4) completed the first transatlantic flight on May 31, 1919, by flying from Rockaway, Long Island, to Plymouth, England, a journey of 4513 miles on which five stops were made en route. Her wing-spread is 126 ft., and her weight when manned and loaded was 14 tons. Lieutenant Commander Albert Cushing Read of the United States Navy commanded her during the flight. Twenty United States destroyers were stationed at intervals of about 70 miles along the route from Newfoundland to the Azores, the longest leg of the flight (1380 miles)

BY

ROBERT ANDREWS MILLIKAN, PH.D., Sc.D.

DIRECTOR OF THE NORMAN BRIDGE LABORATORY OF
PHYSICS, PASADENA, CALIFORNIA

AND

HENRY GORDON GALE, PH.D.

PROFESSOR OF PHYSICS IN THE UNIVERSITY OF CHICAGO

BEING A REVISION OF THE AUTHORS' "A FIRST COURSE IN PHYSICS" DONE IN COLLABORATION WITH

WILLARD R. PYLE, B.S.

HEAD OF THE DEPARTMENT OF PHYSICS, MORRIS HIGH SCHOOL NEW YORK CITY

PREFACE

The chief aim of this book in all of its editions has been to present elementary physics in such a way as to stimulate the pupil to do some thinking on his own account about the hows and whys of the physical world in which he lives. To this end such subjects, and only such subjects, have been included as touch most closely the everyday life of the average pupil. In a word, the endeavor has been to make this book represent the practical, everyday physics which the average person needs to help him to adjust himself to his surroundings and to interpret his own experiences correctly.

But the conditions of modern life are changing at an astonishing rate and calling for the continuous revision of any text which would keep pace with them. For example, within the past ten years the internal-combustion engine has not only taken its place as an agent of equal importance with the steam engine in the world's industries but, what is more important, it has also come more fully into the daily life of the average man and woman than even the dynamo and motor have ever begun to do. The automobile is accordingly given fuller treatment in this new book than it has ever received before in any elementary physics text.

Again, man's conquest of the air, after centuries of failure, is not only the most significant advance, on the practical side, of the twentieth century, but the airplane now attracts the attention and excites the interest of almost every man, woman, and child. Accordingly, the principles underlying this advance, and the methods by which it was brought about, find as full treatment in this volume as is consistent

with the simplicity and clearness demanded in a beginning course in physics. The book may be used, if desired, even in the second year of the high school.

Further, the World War was responsible not only for extraordinary developments in physics but also for demonstrating, both to the American youth and to the leader of American industry, the necessity of the more intensive cultivation of physical science. These developments and these new demands, with which the authors came into the closest touch because of their service in the army both in this country and in France, have been fully reflected in this book, the emphasis, however, being placed upon developments which make for peace rather than for war.

As in preceding editions, the full-page inserts, though a very vital part of the book, are not a necessary and integral part of the course. They have been inserted, in more than double their former number, in order to add human and historic interest and to stimulate the pupil to look farther into a subject than his immediate assignment requires him to do. It is thought that they will be found to be an invaluable adjunct to the course.

Both the order and the treatment are in many places markedly different from those of preceding editions, and reflect the experience of the tens of thousands of teachers who have used this course, many of whom have assisted the authors with their suggestions. Especially in the problems have important improvements been made.

For the sake of indicating in what directions omissions. may be made, if necessary, without interfering with continuity, paragraphs have here and there, as in former editions, been thrown into fine print. These paragraphs will be easily distinguished from the classroom experiments, which are in the same type. They are for the most part descriptions of physical appliances.