“Tell the fellows at the barricade to keep up their courage,” was Stone’s last message to Jack, before the latter abandoned the radio station. “Tell them to watch. I’m going to drop our gas bombs among the Janissaries. They’re marching bunched up and we ought to put a lot of them to sleep. Although we saw only three boatloads on their way here, there must have been a lot more, because there’s a thousand at least on the march below us. Well, here goes.” Jack did not stay to hear Roy Stone’s closing words, however, for at the report of the danger to the revolutionists he was off to see about his father, and Roy spoke to the empty air. Frank swooped low above the close-packed mass of the Janissaries, streaming down the Great Road. High in the air he shut off his engine, and not many had warning of his approach. Even those who did merely gaped at the strange and terrifying sight instead of scattering. Straight down the line of the Great Road flew Frank, and in succession Roy Stone released and dropped the gas bombs. Into the crowded ranks they fell. Not one missed the road. And, as they struck, the clouds of vapor were released. The airplane passed on and Frank, switching on the engine, mounted and then turned to go back over their course and observe what effect their bombs had caused. Deadly, indeed, the execution wrought. Where a few minutes before the Great Road had been alive with marching men, now it was a chaos of writhing forms strangling in the powerful fumes. Many already lay still. Ahead and behind the main body, others fled, stumbling, falling, rising, dashing on, to get away from the unseen enemy that had laid their comrades low. To either side fled still others. Although Roy Stone had assured him in advance that the gas was not fatal in its effects, the spectacle caused Frank to experience a sickish feeling. How terrible it was, he thought, that men should thus be struck down in masses. Even the fact that the Janissaries were atrociously brutal, and richly deserved the worst of fates, was no comfort. Abruptly, he turned and started to mount into the air, heading for the desert. As they passed high above the barricade, Amrath through his glasses could see the defenders busied closing the breach and preparing for a last desperate stand. Not yet were they aware of what had occurred in the valley, for the scene was hidden from them. A little figure, speeding up the Great Road, was seen and was presumed to be that of Jack. Well, he would let the defenders know in a moment that the airplane had done its part, and that an attack in force from the Janissaries need not be looked for, at least not for some time to come.