"We'll wait just ten minutes more," he was told. "I've figured everything down to a fraction, and expect to proceed by clock-work. We want to be well over the line before the moon peeps up. After that we can loaf a bit, and let the old lady get a little way above the horizon. That's so we may have the benefit of her light when we want to land."
The minutes passed slowly. Meanwhile the crowd increased, every man who chanced to be abroad at that hour of the night gathering to see the two Americans start on their mysterious errand. All sorts of guesses were indulged in, many of them of the wildest character. Jack hearing some of this talk, which he half understood, was convulsed in silent laughter over the remarkable ideas that seemed to possess the minds of those French mechanicians and hostlers.
Finally Tom stood up.
"It's time!" he said simply, and Jack understood without any further explanation. He at once proceeded to climb into his seat and complete his simple preparations for the work in hand, being already fully dressed in his fur-lined garments, and with his warm hood and goggles in place.
A minute afterwards Tom called out the word that started the propellers whirling. The motor took up the refrain, and hummed merrily, as though glad to be busy again. Then they were pushed along for a start, gathering momentum so quickly that the mechanicians dropped back to watch the dark object vanish almost wholly from their sight along the level field.
Both boys noticed the great difference between this two-seater and their own active little Nieuports. How clumsy this machine was, and how slow to answer to the call of the pilot! Yet it would be far better for their purpose than two of the small aircraft, since it allowed them to be together.
The few lights of the aviation field near Bar-le-Duc had faded almost entirely out of sight by the time Tom turned to the north and headed for Verdun. True, he might have pointed the nose of the airplane directly east, and saved considerable distance, but there were good reasons for not doing this.
To cross the German lines further south would surely convince the Teutons that the aviators were heading for the vicinity of Metz, which was just what Tom did not wish to have happen. Then again, his chart covered only the direct line between Verdun and the fortified city of Lorraine that forty-odd years back had been French territory, before the Germans seized it as spoils after the war that made France a republic for the third time.