“Trouble’s past.  Admiral signaling keep on this level, Tom!” called out the observer.

“Got you, Jack!” came the answer, heard above the rushing noises that “made the welkin ring,” as Jack told himself.

The firing ceased as the German gunners realized, to their chagrin doubtless, that again their intended prey had eluded them.  They must have set those anti-aircraft quick-firers of theirs in fresh elevated emplacements after the Yankees had taken the measure of their power to do harm; but the trap, if such it was intended to be, had failed to catch a single victim.

“Did they get any of our crowd?” Tom called out, feeling considerable uneasiness as to the result of the bombardment.

“Never touched us,” he was immediately assured by the observant Jack.  “All the same it was a smart trick, and somebody’s bound to be hauled over the coals on account of the blunder.”

“Yes,” admitted Tom, speaking loud so as to be heard above the roar of the numerous planes around them, “because it might have played hob with the squadron, and even ruined the success of the whole expedition.”

After that they relapsed into silence.  It was exceedingly difficult to try to keep up any sort of conversation while going at such a furious pace through the upper air currents.  Besides, the night was cold at such an elevation, and consequently both boys had their heads well muffled up, making use of hoods with goggles for the purpose.  They also wore gloves on their hands, as well as heavy sweaters under their leather-lined coats.

The formation, in a way, reminded Jack of many a flock of wild geese that he had seen flying north or south over Virginia in their spring and autumn migrations.  In the lead went the battleplane containing the squadron commander, forming the apex of the triangle, and showing a fiery red eye in the shape of an automobile rear light as a rallying point for all the other machines.

Then the seven other battleplanes sank away from the apex, three on one side and four on the other, that of the Air Service Boys being the one to the rear of all the rest.

Flying two and two abreast, and guarded on both sides by those sturdy fighting craft came the four huge bombers, each heavily laden with the most destructive of explosives.  They, too, could show teeth if cornered and compelled to depend on their own defensive powers; for each of them carried a machine gun, of which the observer had been trained to make good use, just as he must know how to drop his bombs successfully when the proper instant arrived.

All seemed quiet just at present, but none of those guiding the aerial racing craft deceived themselves with the belief that this could last long.  It went without saying that the Huns must realize the necessity for guarding the important bridge across which their beaten armies were flocking day and night in constantly increasing numbers.  Unless the guns could be taken across in safety, they stood to lose many of their best batteries.