Far below they could see a myriad of dots of lights. These might be the fires of the hostile armies, for the weather still remained cold. In the nights particularly a blaze was acceptable to such of the fighting men as had to remain out of the trenches and back of the lines.
Tom could also see colored lights, which he guessed were rockets. The Germans were sending up signals. He wondered if their starting out was known, or suspected, and whether some sort of bombardment was in store for the raiders as they passed over the Teuton front.
After the recent raid that was said to have been so very successful it seemed reasonable to believe that the German High Command would expect a repetition while the moon still gave a favorable light.
Tom quickly learned that his guess had been a good one. From below came a jumble of sounds faintly heard, along with the regular pulsations of his powerful motor. Then just under them shrapnel began to burst in great quantities. But the French knew just how high the enemy anti-aircraft guns were capable of sending their missiles, for seldom did a shell come dangerously close to the raiding machines.
They were just out of range, and that peril seemed to be put at rest. Presently, from the indications, they knew they were beyond the hostile lines, and doubtless passing over the country that lay between Verdun and the border of Lorraine.
In the lead was the head pilot, a man who possessed a wonderful ability to take an expedition like this out, find his objective, perhaps one hundred and fifty miles away, and come back, after dropping tons of high explosives.
Those who followed were strung out in two diverging lines, just as wild geese always fly, forming the letter V. In moving in this formation the danger of collision was more or less done away with. Besides, every pilot knew just where his location in the line was, and could keep watch of those ahead, while looking for the signals agreed upon.
All communications had to be carried on with flares, since sounds were utterly out of the question. As a rule it was the duty of the observer to discover such signals, and pass them on to the rear unless, as in the case of the two chums, they brought up the line, being the very last unit of the eleven machines in the bombing squadron.
Now and then the moon would hide behind banks of fleecy clouds, but only to reappear again a little later, to shine with undiminished light. Jack wondered whether a storm might come along while they were aloft. He had been in several small flurries of the kind, but that was in the broad light of day. To be caught when on a night journey would be a new experience for both of them.
After a while he made out that they were now above some river, and had apparently altered their course, as if the pilot meant to follow the stream.