Louder grew the discordant sounds that spoke of the hot work being done along a line that must cover many miles of front. In places the Germans must be attacking furiously again, hurling masses of fresh troops forward in hopes of pressing the Allies back once more.

“But they’ve shot their blooming bolt,” said the van driver, exultantly. “Gas is wot done it, I tell you; but our men have turned and pushed the mob back a full mile or so, I hears. There we stick, and they can’t budge us, try it as they will.”

Every chance Amos got, when the road was fairly clear of trees ahead, he leaned forward and seemed to be intently examining the heavens as though fearful that it might start in and rain again.

Jack knew, however, it was something besides this that was causing the other to act as he did; and that it concerned those venturesome fliers who during the entire day would be sailing back and forth through the upper air currents, spying on the troop movements of the enemy, and sending numerous valuable messages back to those who with glasses bearing on the aeroplanes were reading to receive such news as came.

“I can see half a dozen of them sailing around away off there, Jack,” remarked Amos, with a vein of deep anxiety in his voice and manner. “I wonder if one of them can be Frank. They’re too far away right now for me to say which belong to the Allies and which are Taubes of the enemy.”

The chauffeur, while not knowing why they should have any particular interest in aeroplanes, kindly volunteered to pick out those that were connected with the cause of the Allies.

“Germans always have a queer way of flying,” he explained. “They all learn to do things the same way like they was parts of a big machine. Our men go it every one like he learned his own style. But say, boys, I have to turn off the road here and follow this trail which leads to a hospital where I gets me load. If so be you’d want to keep on that way you’re welcome to stay aboard with me.”

Jack, however, believed that their end would be best attained if they kept on in a direct line for the village where they had passed that night at the time the great German drive broke like a water dam, and pressed the Allied armies back for several miles.

They trudged along for half a mile. Then back of them came a battery of field guns, swinging to the front for service. The boys stepped out of the way, and as the artillery swept past they waved a hand to the grim men in khaki sitting on the seats of gun carriage and caisson.

“I wouldn’t mind riding on one of those, given half a chance,” Amos was saying a little enviously, for as the horses were galloping there was a promise that the fresh battery would soon be wheeled in position to take toll of the charging Prussians.