When I came to examine the chamber, I found it to be neither so large nor so lofty as I had first supposed. The general height of it was not above five feet, though in parts it rose to ten feet or more. I had soon made a tour about the chamber, the compass of which was perhaps sixty or seventy feet, and in one corner of it I at last discovered an opening, through which, I did not doubt, came the current of air I have before mentioned. It was, as I found when I held my torch to it, a very low and narrow passage, not above four feet high, and the draught of air was so strong that it made my torch flare, and, indeed, was like to blow it out. This made me consider whether I had not better rest content and go no further; but curiosity was strong within me, and so I went into the passage, or tunnel, having to bend my body very low, and crept along with great caution, holding the torch in front of me lest I came unawares upon a chasm and broke my neck. The passage seemed to me to incline slightly downward, though I could not be sure of this, since there were not only several crooks and turns in it, so that not many yards of it were straight, but also it was in some parts pretty near choked with rocks and stones, which I supposed had fallen from the roof and sides. However, I picked my way among these obstacles when they occurred, and found as I went on that the passage became both wider and loftier, so that I was able to stand upright. After I had gone some distance through this tunnel, wondering whether it was natural or had been made by men's hands, and inclining to the former belief, I perceived that it was joined by another passage which ran into it from my right hand, and the two passages thus joined in one became a tunnel which increased both in width and height the further I went. Whereas at starting from the cavern I had had to bend low, with little space on either side of me, I now found myself in a passage which in some parts was as much as twenty feet high, as near as I could guess in the deceitful light of my torch, and so wide that five or six men could easily have walked abreast in it. And as I still kept my eyes cast down, being heedful of my footing, I perceived by and by on the floor of the passage sundry small whitish objects which, when I stooped to examine them, I found to be shells, and they became more numerous the further I went. I began now to question with myself whether this tunnel did not communicate with the sea, and whether the sea ever came up through it so far into the interior of the island, for the cavern whence I had started on this journey was directly below our hut, and that was situate at least half a mile from the sea-shore.