As they ran they heard behind them a shrill screaming and a furious beating of gongs. Then from the tall drum-tower in the centre of the city came a deep, booming sound that could be heard for miles. The great drum that is only sounded in times of public peril was arousing the citizens and sending them swarming from their houses. Torches appeared not only in the streets but on the wall behind our flying lads. Then, to Rob's dismay, others began to gleam in front of them. To be sure, these still were a long distance away, but they gave certain evidence that flight in that direction must come to a speedy end.
"What is the use of running any farther?" asked Rob. "We'll only fall in with that torch-light procession all the sooner. Seems to me we might as well stop where we are and see about getting down off this perch."
"There's only one place to get down," answered Jo, "and it still is ahead of us. Run faster! We've got to reach it first."
So the fugitives put on an added burst of speed, though to Rob it seemed that they were only rushing directly into the arms of the advancing torch-bearers.
Suddenly Jo exclaimed, breathlessly, "Here's the place!" and then, to Rob's dismay, he took a flying leap off the parapet into the gulf of impenetrable blackness lying on the outer side of the wall.
For a moment the young American turned sick with the thought that, despairing of ultimate escape, his comrade had chosen death by suicide, and now lay lifeless at the foot of the lofty battlement.
Then came the familiar voice rising from some unknown depth, and calling on him to follow.
"Jump, Rob!" it cried; "you'll land all right, the same as I have."
Even with this assurance our lad hesitated to leap into the darkness. He knew that the wall was at least fifty feet high. There was at its bottom no moat filled with water, into which one might launch himself with safety. "Nor is there any pile of feather-beds, that I know of," he thought, grimly.
From both sides lines of torches were steadily advancing, while up from the city rose a tumult of angry voices. Only in the outside blackness that already had engulfed his friend was there the slightest promise of escape.