I have made my way into various underground halls, the mansions of bats and stalactites. Those near Deloraine in Tasmania are by far the most spacious in ascertained length that I have seen. Those at Wonderfontein in the Transvaal, of which I will speak in the next volume, may be, and probably are, larger still, but they have never been explored. In both of these the stalactites are much poorer in form than in the caves of the Cheddar cliffs,--which however are comparatively small. The Mammoth Caves in Kentucky I have not visited; but I do not understand that the subterranean formations are peculiarly grand. In the Cango Grottoes the chambers are very much bigger than in the Tasmanian Caves. They also have not been fully explored. But the wonderful forms and vagaries of the stalactites are infinitely finer than anything I have seen elsewhere. We brought with us many blue lights,--a sort of luminary which spreads a powerful glare to a considerable distance for three or four minutes,--without which it would be impossible to see the shapes around. The candles which we carried with us for our own guidance had little or no effect. In some places the droppings had assumed the shape of falling curtains. Across the whole side of a hall, perhaps sixty feet long, these would hang in regular pendent drapery, fold upon fold, seeming to be as equal and regular as might be the heavy folds protecting some inner sacred chapel. And in the middle of the folds there would be the entrance, through which priests and choristers and people might walk as soon as the machinery had been put to work and the curtain had been withdrawn. In other places there would hang from the roof the collected gathered pleats, all regular, as though the machinery had been at work. Here there was a huge organ with its pipes, and some grotesque figure at the top of it as though the constructor of all these things had feared no raillery. In other places there were harps against the walls, from which, as the blue lights burned, one expected to hear sounds of perhaps not celestial minstrelsy. And pillars were erected up to the ceiling,--not a low grovelling ceiling against which the timid visitor might fear to strike his head, but a noble roof, perfected, groined, high up, as should be that of a noble hall. That the columns had in fact come drop by drop from the rock above us did not alter their appearance. There was one very thick, of various shapes, grotesque and daring, looking as though the base were some wondrous animal of hideous form that had been made to bear the superstructure from age to age. Then as the eye would struggle to examine it upwards, and to divide the details each from the others, the blue light would go out and the mystery would remain. Another blue light would be made to burn; but bats would come flitting through, disturbing all investigation;--and the mystery would still remain.