This makes them slow to answer to the call of the pilot; and when attacked by the more nimble Fokkers they have a hard time to keep from being shot down. That is why a number of the Nieuports with well known "aces" in charge, must always be hovering over the fire controls, ready to fly to their assistance in case they are attacked.
"Things are surely beginning to happen," murmured Tom. "The Boches seem to be in an unusually fierce and aggressive humor on this particular morning."
The youth was right in this. The Germans had been thrown out of numerous hard-won positions lately, and this gave them cause for feeling bitterly toward the French.
By the time the American unit reached the field of battle, several furious combats had already taken place with disastrous results. Two of the enemy machines had been sent down, one of them in flames, after the pilot had fallen at his post, fairly riddled by the gunfire of the Frenchman. A birdman had also paid the great debt on the side of Petain's men. As the score was two against one there seemed no cause for depression.
The Americans would not be kept out of the fight for long. No sooner were three adventurous Teuton pilots seen climbing up to attack the big fire control machine when Tom's companions dropped down from the "ceiling" to engage them.
Tom watched everything as though photographing the thrilling happenings on his brain forever. He had a greater interest in these things than at any previous period of his life, for was he not also hovering over that observation Caudron, upon which the movements of the advancing French troops depended? At any minute might he not receive the signal from the captain to attack some fresh Boche, who had climbed high above the battle lines to join the general scrimmage, or else "get" the big French machine while its defenders had their hands full with his comrades?
Had Tom been able to use his binoculars just then, which was out of the question of course, and look back to where the monster French guns were firing, he might have noticed various white sheets spread out in fantastic patterns on the ground, the picture varying every little while.
These were used to "talk" with the observer who was sending those messages from the fire-control plane, telling the gunners just how many metres their fire was short, long, to the right, or to the left of their intended objective.
Then again information was being sent by another observer to the advancing infantry, warning them of perils that lay in their way, which might have cost them great and grievous losses if they remained unknown until the German trap was sprung.
The morning was advancing. Tom had seen his comrades chase off several flocks of enemy aircraft that endeavored to interrupt the deadly work of the observers. As yet his anticipated chance had not come. He was beginning to feel impatient. Could it be that he must stay there almost up among the clouds, and only be a "looker-on?"