Time was indeed getting short. In ten minutes more the bomb in the coal barge would go off. There was nothing else to do. Either the _Nautilus_ had to be raised at once or the time bomb in the coal barge had to be disengaged to avert what might prove to be a disaster for the two Brighton boys. Since the air pump was out of commission it was impossible for the boys to go out through the air-lock into the access tube. There was no way to swing back the heavy doors with the compressed air cut off. Neither could the ballast tanks under the _Nautilus_ and the access tube be blown out so long as the air pump on the _Jules Verne_ was out of commission. In this extremity the cables were the only means of lifting the _Nautilus_ out of the depths. The men must be working now, for it was some job to wind the winches by hand, and progress through the water would be so much slower than if the diving chamber were "trimmed" in the regular way. Jay and Dick were not cowards. They had proved that a number of times in school and while they served in the Navy abroad during the war. Each youth had proved his gameness on more than one occasion. So in the present extremity they were far from flabbergasted at the failure of the air apparatus on the mother ship just after they had placed a time bomb in the coal barge. Cool and collected they awaited developments. Each was a quick-witted lad and could be counted on to make the best of any situation. Finally the telephone bell rang. Jay wrenched off the receiver. Larry was talking like a phonograph in high gear. "Bad news, fellows. Just as they were winding for the first heavy pull on the cables the right main cable on the under side of the access tube snapped clean in two. The whole system of cables is put out of business. Cap says----" At this juncture Captain Austin leaped forward and took up the telephone. "How much time have you got until your bomb goes off, boys?" he called down the tube, quietly and without any show of apprehension. Jay eyed his watch for a second. "Not more than five minutes," came Jay's even reply. "There's only one thing to do," the Captain told him in reassuring tones. "Our pump has gone back on us and the steel cables have parted on us--a combination of hard luck that would not happen once in a thousand years. Can you get your bomb back in any way and detach it?" Jay said they would try, and turned toward his chum. "It's our only chance now, Dick," he told him. Together they flung back the aquascope to grapple for the bomb they had set under the deck of the coal barge. But to their horror and dismay they found that the tide had swung the _Nautilus_ slightly away from the opening in the barge--at least three or four feet! CHAPTER XVI AN EXPLOSION IMPENDS