"Tell you what, Stubbs. I'll put on a little extra speed, just for your benefit. We'll get you back on terra firma just as soon as we can."

Stubbs' only reply was another moan.

"Well, Chester," said Hal, "here we are again, flying over an enemy's country. May we be as fortunate as we have been before."

"Which we shall be," was Chester's quiet response. "We have had our share of bad luck in the last few days. Fortune must smile on us at last."

And Chester proved himself a true prophet; for, before another sun had risen and set, the huge air craft had carried its four occupants safely across the Austrian empire and beyond the Montenegrin border. And here, among these hardy mountaineers, among the best fighters in the world—among the people of this little Balkan kingdom—the smallest to declare war against the Teuton oppressor—the lads were to see more of the horrors of war—were again to play active parts in the struggle. And also they were to see service with the heroic Servian troops, than whom there are none braver.

But these adventures must come in their proper place; and so, for the time, we must again take leave of these two lads and their brave companions and friends, but only to meet them again in a succeeding volume, entitled: "The Boy Allies in the Balkan Campaign; or The Struggle to Save a Nation."