feeling with my feet for standing ground. There was none in front, but on either edge there was just resting room for the foot; so this chasm was passed in safety. I shouted out to my companions to take care, and the guide returning, we examined what we had escaped: it was a black hole, into which we threw stones, and calculating the number of seconds they took in reaching the first obstruction, we found it about three hundred feet deep. The stones bounded on the rocks below, and we could hear them strike and strike again, till they either reached the bottom, or till the sound was lost in the distance. We then advanced to a large hall, apparently supported in the middle by a massive pillar, which was in fact but a huge stalactite. From above fell a continued shower of cold water, which doubtless was the cause of those innumerable stalactites that adorned the roof. We continued advancing for about seventy or eighty yards farther, the cave getting narrower and narrower till two could not move abreast. Except where the guano lay, the walking was difficult, as the rocks were wet and excessively slippery, and open chasms were not rare. In the farther end we were shown the places where the best nests were obtained: the dryest portion of the sides of the cave are chosen by the birds, and these appeared seldom to occur--I found but one inferior nest remaining. Disturbed by our movements and by yesterday’s havoc, the swallows were in great commotion, and flew round and round, and darted so near our solitary light that we were in great fear for its existence. The natives say that in these caves there are two species of birds--the one that builds the edible nest, and another that takes up its quarters near the entrance, and disturbs, and even attacks the more valuable tenants. The Kayans endeavour to destroy these, and while we were there knocked down some nests constructed of moss, and adhering to the rock by a glutinous but coarse substance. The fine edible one looks like pure isinglass, with some amount of roughness on its surface. The best I have seen are four inches round the upper edge, and appear like a portion of a whitish cup stuck against a wall. On examining the construction of the mountain, one’s first impression is, that all these huge rocks were thrown in heaps together; but, doubtless, water is the agent in forming these caves and the deep fissures that penetrate to the water-line in these limestone mountains. I believe the guides took us to the smallest cave, as I am sure, from the produce of the district, that there must be many more better adapted for the swallows, or else that they must be very numerous. In fact, the guides told us that Siñgauding had several others, and that Tamawan in right of his wife had the best. As they showed no inclination to take us to the uncleared caves, we did not press them.