WHEN the biplane bearing Chief Roque and Billy Barry cleared the mountain top, the pilot and observer had a fixed understanding that every Russian camp was to be given a wide berth, for with fuel tanks going dry it would have been the top of folly to invite a long chase from the Muscovite airmen. And then, too, it was no part of a safe and sane program to risk an enforced descent in hostile domain. "Keep her nose southward," commanded Roque, "and we may find the Austrian lines before we have lost our power. It's a desperate chance, of course, but there is nothing else to be done." A precious hour was consumed in fruitless flight, with never a cheering sign of the friendly forces sought by the anxious aviators. "It has just dawned upon me that our army has again entrenched in the mountains, for we could not possibly have come so far in the open without a single sight that would encourage further search in this direction." Roque trained his glasses to the east, where the snow-capped peaks of the Carpathians were showing in the dim distance. "It's a good forty miles in that turn," figured Billy, "and whether we can make it or not with an inch or two of petrol is a close guess." "Make a try for it, and count on the wind to help." The mind of the chief was set on this last throw. One satisfaction to Billy in this change of course was the definite objective--hit or miss, they were no longer wandering. Within a mile of the first slope the pilot knew that the jig was up with the motors. Over his shoulder, he called to the observer: "This is no Zeppelin with a gas range, and it's the turf for us now." The motors clanked and ceased to hum. The aëroplane took the downshoot and skated to a standstill on the slippery soil. "Stranded but not wrecked." Roque accepted the inevitable with fairly good grace for him. "What's the next move?" Billy was curious to know what the chief had in stock for the emergency. The boy was not immediately enlightened, for Roque evidently proposed to reach speech through meditation. The secret agent with his long coat-tail dusted the powdery snow from a flat stone and calmly took his ease behind the glowing tip of a long cigar. "He must have wireless communication with a tobacco shop," thought Billy, "for he never fails to find one of those black rolls when he reaches for it." The young pilot, muffled in a blanket, stuck to his seat in the biplane. It was his fortune, however, to see the first rift in their clouded luck. The color scheme of the mountain side, brown, white and gray, added in the passing minute some new and stirring effects. On a higher slope were arrayed a number of men wearing crest helmets, blue jackets and red trousers. "Say, boss," drawled Billy, when he caught sight of these gorgeous figures, "there's a circus band coming down the mountains." Roque looked up. "Austrian dragoons!" he exclaimed. "We've rung the bell this time!"