Billy of course could not tell me this, having lost his bearings just as completely as I had done. All that we knew was that the cavern was not reached by the passage along which I had been going, for neither Billy nor I had encountered water in our outward journey. It seemed to me that we had both wandered into the passage which I had observed to run into the other from the right hand, and if this was so, we had but to go in the same direction as I had been going when Billy met me, and to cling to the wall on the left side, and we should by and by find ourselves at the fork of the two passages. And, indeed, we had not gone above a dozen paces when Billy, who was in front, cried that the wall turned a corner, and when we reached it we wheeled round in the same direction, and in due time came to the cavern, which, though it had seemed dark to me before, was now light by comparison with the blackness of the tunnel we had left. I asked Billy whether he had lengthened the ladder, and when he confessed that he had not, I wondered how we were to ascend to our hut again, for the bottom of the ladder was out of my reach. But Billy solved this difficulty by getting on to my shoulders and then grasping the ladder, by which he very nimbly climbed to the surface. There being no room in the shaft for him to bend down and assist me, I had to wait until he had lengthened the ladder, which he did very quickly, blaming himself for not having done it before. Thus we came safely to our hut again, and both having had enough of underground passages for that day, we determined to go on another expedition later, indeed, very soon, for Billy was eager to explore the tunnel to its end, when I had told him of the largeness of it, and of the shells on its floor. I did not tell him my tale at once, for the moment we came up into our hut we were aware that it had been visited in our absence. Having made our discovery of the cavern by accident, and gone down into it without premeditation, we had not thought to shut the door of the hut, which, being open, those rascally dogs of which I have spoken more than once had made an irruption. By great good luck there was nothing that they could destroy, but they had thrown down a pile of cocoa-nuts we had in one corner, and these lay scattered all about as if they had played ball with them. I doubt not they would have made an attempt, as they did afterwards, to plunder our poultry-run, but it would appear that they had not discovered our absence for some time, and had been startled away by the sound of us returning. We determined, when we should descend again into the cavern, to close our door very firmly.