Four hundred feet.
Suddenly a light flashed from one of the towers, and a number of men, one of them carrying a lantern, emerged and marched along the broad flat roof. "Rounds, by Jove!" gasped Dacres, then springing to the emergency switch controlling the supply of ultra-hydrogen and the ballonettes, he thrust it down.
The hiss of compressed air that followed seemed to the crew loud enough to arouse the whole garrison. Simultaneously the downward movement was checked and the section leapt quickly to a height of a thousand feet.
"Keep her there," ordered Dacres, then, glass in hand, he returned to his post of observation. Thank heavens the visiting rounds had neither heard nor seen the danger that threatened them. The crew could catch the sibilant challenge of the sentry as the soldiers approached his post. Having satisfied themselves that all was well, the rounds passed on to the next sentry, and so on till they had completed a tour of the walls. Then, descending to the courtyard by a flight of steps, the party crossed the patio and disappeared within the guard-room.
"We'll wait another half-hour," said Dacres. "Perhaps by that time the sentries will not be on the alert."
"Very good, sir," replied Callaghan. "I've tumbled across South American soldiers before now, and, between you and me, sir, they ain't up to much."
"Cap'n coming alongside, sir," reported one of the crew as coolly as if announcing the approach of the captain's gig towards a man-of-war.
Silently the major part of the "Meteor" glided within fifty feet of No. 5 section.
"What are you waiting for?" demanded Whittinghame.
"We saw the rounds were out, sir," replied Dacres.