There was an explosion that, notwithstanding the distance, seemed to shake the everlasting hills to their very foundations.
The men on the terrace stared aghast, each at the other.
"The die is cast," cried the one with the commanding voice, "and an hour too soon!"
[CHAPTER XXIII.]
A LEAP FOR LIBERTY.
The Boy Aviators had just left the mess hall, and were proceeding to the hangars where the No. 3's were housed, fully intending to carry out their compromise plan of giving Roque and Schneider the means to escape, and return themselves as hostages for the honor of the aviation chief.
Shortly before seven o'clock on this eventful evening, Billy and Henri had the biplanes in order for the arranged visit to St. Michael road, and the delivery of one or both of the machines to their former owner, supposedly in waiting in the shadow of the two towers.
"It is really a relief that the time is drawing nigh for us to get off the rack. I believe we are doing the square thing, but sure we have had few easy moments during these last forty-eight hours."
Billy heaved a sigh when reviewing this disturbing experience.
Henri turned just then to salute the aviation chief. The boy's greeting had none of the cheery note usually there. He did not know how it would be several hours hence.