And then he began to turn over in his mind the possibilities of the situation. How long would the creature be likely to hold him thus prisoner? Would it release him when at length it realised the impossibility of penetrating his armour? And, if so, how long was it likely to be ere the release came? Failing to make a meal of him, the thing would undoubtedly be obliged to go forth, sooner or later, to seek for food. But Mildmay had only the most elementary knowledge as to the habits of the octopus, and he had a hazy idea that, like certain snakes, the creature might only feed at more or less long intervals, in which case he might be held a prisoner for a week or more. This was a distinctly disquieting reflection while it lasted, but it presently occurred to him that it was by no means probable that, let the creature's habits be what they might, it would retain that vice-like grip upon him for any very lengthened period, and his chance would come when that grip relaxed. And it was an easy step from that conclusion to the next, which was that he must do what he could to cause the grip to relax as quickly as possible. He had already observed that the creature tightened the clasp of its tentacles about him whenever he moved or struggled; and the obvious corollary from this was that, the more quiescent he could remain, the sooner would his opportunity come to wrench an arm free and use his deadly dagger. Meanwhile, on board the _Flying Fish_, Lethbridge, intent upon making the time pass as pleasantly as possible for the ladies, cooped up below deck in the saloons, conducted them to a window in the dining-saloon, from which the wreck and the reef were clearly visible, and from which they could watch the movements of the four adventurous divers. For some twenty minutes or so after the quartette had left them, the occupants of the saloon had to be content with such interest and amusement as was to be obtained by observing the movements of the numerous fish outside, including a little thrill of horror when a big shark, which went drifting aimlessly past, turned aside for a moment to thrust his great shovel-snout up against the tremendously thick and especially toughened plate-glass window out of which they were gazing. They were at once full of apprehension lest the monster should remain in the neighbourhood, and attack the divers upon their appearance on the sandy floor below; and Lady Elphinstone even begged the colonel to go down below and warn the adventurers of its proximity as well as urge them to defer their excursion. But Lethbridge laughed so heartily at the idea of their being in any danger from a mere shark, and explained to them so clearly that the shark would have absolutely no chance whatever against men equipped as the divers were, that they permitted themselves to be reassured.