picture the familiar scenes of rushing, bustling life back there! Crowds were now pouring into the subways and surface cars or climbing to the level of the "L's." This was the third—the latest homeward wave. The five o'clock people had, for the most part, already reached their homes and were thinking about their dinner; the five-thirties were well upon their way.

How the millions of his native city and of other cities and towns, and even of the country districts, all moved upon schedule! Clocks and watches told them when to get up, when to eat their breakfasts, when to catch their trains, reach their work, eat their lunches, and return to their homes. Newspapers came out at certain hours; mails were delivered at definite moments; stores and mills and factories all began their work at specified times.

What a tremendous activity there was, back there in America, and how smoothly it all ran—smooth as clock-work! Why, you might almost say it ran by clock-work! The millions of watches in millions of pockets, the millions of clocks on millions of walls, all running steadily together—these were what kept the complicated machinery of modern life from getting tangled and confused.

Yes; but what did people do before they had such timepieces? Back in the very beginning, before they had invented or manufactured anything—far back in the days of the caveman—even those people must have had some method of telling time.

A bright star drew above the shadowy outline of a hill. At first the man in khaki thought that it might be a distant star-shell; but no, it was too steady and too still. Ah yes, the stars were there, even in the very beginning—and the moon and the sun, they were as regular then as now; perhaps these were the timepieces of his earliest ancestors.

A slight rustle of anticipation stirred through the waiting line and his thoughts flashed back to the present. His eyes fixed themselves again on the ghostly splinters of light at his wrist. The long hand had almost reached the figure 4—the moment when the bombardment would begin.

He and his comrades braced themselves—and the night was shattered by the crash of artillery.

CHAPTER ONE
The Man Animal and Nature's Timepieces

The story of the watch that you hold in your hand to-day began countless centuries ago, and is as long as the history of the human race. When our earliest ancestors, living in caves, noted the regular succession of day and night, and saw how the shadows changed regularly in length and direction as day grew on toward night, then was the first, faint, feeble germ of the beginning of time-reckoning and time-measurement. The world was very, very young, so far as man was concerned, when there occurred some such scene as this:

It is early morning. The soft, red sandstone cliffs are bathed in the golden glow of dawn. As the great sun climbs higher in the eastern sky, the sharply outlined shadow of the opposite cliff descends slowly along the western wall of the narrow canyon. A shaggy head appears from an opening, half-way up the cliff, and is followed by the grotesque, stooping figure of a long-armed man, hairy and nearly naked, save for a girdle of skins. He grasps a short, thick stick, to one end of which a sharpened stone has been bound by many crossing thongs, and, without a word, he makes his way down among the bushes and stones toward the bed of the creek.

Another head appears at the same opening in the cliff—that of a brown-skinned woman with high cheek-bones, a flat nose, and tangled hair. She shouts after the retreating form of the man, and he stops, and turns abruptly. Then he points to the edge of