Then, with the suddenness of a thunderbolt, all their hopes were dashed out. So swiftly did disaster descend that none had a chance to say how or whence it came--but it was disaster complete and irretrievable. Perhaps it was that the anchor-chain holding the submarine had snapped, or that some water had seeped in between the side of the vessel and the glass wall. At all events, the submarine was plainly visible one moment, the men pumping the viscid cement through long tubes to the very extremities of the crack; and the next moment there was only a dim shadow flitting away into a watery obscurity. For an instant there was an awed silence. Then, as comprehension dawned upon the crowd, a convulsive shudder swept it through and through, and a howl of horror and dismay rang forth. Men glanced askance at their neighbors, blank terror gaping from their eyes; and all at once, as by a common impulse, hundreds pressed confusedly toward the wall, as though they might succor thus those unfortunates lost in the briny wastes. But many, conscious of the futility of all action, sadly remained in their places, and mutely bowed their heads--a tribute of respect for the drowned. * * * * * [Illustration: It was only by degrees that I made out its features, and saw what resembled an enormous piece of cracked crockery. From an amorphous central blur several feet across, great seams and fissures ran in different directions with long spidery arms ... one of the ships pressed itself against the wall, after which the port hole was opened and the men poured cement into the cracks.] * * * * * CHAPTER XXVIII The Waters Retreat The eight days that followed the discovery of the crack were among the most harrying I had ever spent. Indeed, they were among the most harrying that any resident of Atlantis had ever spent. That the peril was acute became more and more apparent as the days went by and the damage was not repaired--the submarine disaster which I had witnessed was but the precursor to other and not less frightful disasters. Vessel after vessel battled with the swirling waters in the effort to force itself against the wall and cement the crack; and vessel after vessel was shaken away like a twig by the fury of the maelstrom. Sometimes, fortunately, the portholes were shut in time and the crew managed to save their lives; but on other occasions the maddened waters snatched their prey; and before a week had gone by Atlantis was mourning for seven lost parties of rescuers.