It stood among some trees, and was unquestionably well fitted to serve the German High Commander as headquarters until such time as the Americans drawing near forced him to move back to Sedan, and then cross over into Belgium near its junction with Luxembourg.

The bombers now altered their formation. Instead of moving forward in a compact mass they formed two parallel lines but a short distance apart, five machines to each column.

Jack looked across to the companion plane and distinguished both pilot and observer crouching at their posts, eager to get into action. It seemed as though he could easily toss a coin over and make it land in the other machine, so close did they range along, with buzzing motors cut down to slower speed so as not to interfere too much with the dropping of the bombs.

Each plane was to let just one missile go, and no more. If the castle had one stone left on another after the rain of aerial torpedoes had come to an end, it would be vastly surprising.

True, it was a French chateau, and it seemed too bad to have to expend any of their precious bombs in bringing about its downfall. But of course they knew full well it was the policy of the Huns never to leave anything intact that could be of the slightest assistance or comfort to the enemy. Hence the annihilation of the chateau was already ordained when Ludendorff should be through using it.

Jack primed himself for his work, though it must be Tom who would give the word when the exact second arrived for the bomb to be released. One pressure on the trigger, and down through the slanting tube would speed the messenger of destruction, bent on its fateful errand.

They were one of the last pair in line, consequently they might expect to hear some sign of the dreadful work before their time came to join in.

Guns were beginning to sound, and the raiders could see spiteful flashes here and there. Evidently, if Ludendorff did have his headquarters here, he had been judicious enough to mount a number of anti-aircraft guns to combat the raiding planes should they appear at any time.

But the firing was only haphazard work, because the searchlight that began now to play upon the airplanes could reveal only one bomber at a time. Thus the shrapnel burst much above their level, so deceptive was the glare.

Then came a sudden, terrific crash, sounding almost as if the battery of Heaven's heaviest artillery had broken loose in one frightful thunderclap. At the same time a blinding flash from below showed Jack flying timbers and scattering stones.