The time for talking had passed. With the motor working noisily, and the twin propellers churning the air, they could hardly have heard the discharge of one of the 'Big Berthas', as the Allies were wont to call the monster Krupp guns, and so called them because a woman whose maiden name had been Bertha Krupp, owned a big interest in the works where they were manufactured.

All was dark around and below them. Above the stars shone, and gave a small amount of cold, cheery light. Tom had made a study of the heavens, and was able to steer by means of the stars. The aviator is often as much dependent on compass and heavenly bodies to shape his course as the sailor hundreds of miles away from land.

Tom was in no especial hurry. He had carefully thought out his plans, and meant to pass over Verdun at just a certain time. Then would come the two lines of hostile trenches, and the ordeal of searchlights and shrapnel. Once that was done with, they had really little further to fear.

The minutes slipped away. Under ordinary conditions they were accustomed to making that thirty miles in just about half that number of minutes, thanks to the ability of the speedy Nieuports to cover distance. It would be twice that now before they would find themselves at the front.

Already they could see various signs to tell them they were drawing near. Rockets used as signals of various kinds ascended at intervals, and burst. Others of the star variety, and which discharged glowing white electric balls that lighted the earth below, could also be seen. One side or the other apparently had some reason for desiring to scrutinize a special sector of terrain in No-Man's-Land, the disputed region lying between the hostile trenches.

Jack used his eyes to advantage. These things had not yet grown stale with him, for he still found himself filled with awe and wonder when gazing down from a lofty height at the world shrouded in darkness below.

There within a comparatively short distance, that might not be over twenty miles, a round million of soldiers were gathered, armed with numberless engines of destruction of the most ponderous nature imaginable. It was enough to give any one a genuine thrill, and Jack felt such a sensation creeping over him.

The crucial time had now come. They were passing over the line of the French trenches. Jack knew this from various signs, and also that in another minute they might expect to be spotted by some of the enemy searchlights. These would be unmasked, and trained on the heavens in the effort to locate the cause of that well known clattering noise above.

This speedily came about. First one long shaft of dazzling light rushed back and forth; then others joined in the hunt, until presently they focussed on the progressing two-seater pushing north.

Then began the bombardment. Numerous anti-aircraft guns were poking their noses upward in anticipation of just such a call. Their crews commenced to shower the shrapnel around and below the bird of passage, whose mission, whatever it might prove to be, could mean only evil to the Teuton cause.