It is difficult to imagine any thing more laborious than to wander about in this cavern. As the road had shewed itself at the entrance of the cavern, so it continued throughout its whole extent. The path consisted entirely of loose fragments of lava heaped one upon the other, over which we had to clamber with great labour. None of us could afford to help the others; each one was fully occupied with himself. There was not a single spot to be seen on which we could have stood without holding fast at the same time with our hands. We were sometimes obliged to seat ourselves on a stone, and so to slide down; at others, to take hands and pull one another to the top of high blocks of stone. We came to several immense basins, or craters, which opened above our heads, but were inaccessible, the sides being too steep for us to climb. The light which entered through these openings was scarcely enough to illumine the principal path, much less the numerous by-paths. At Kalmannstunga I had endeavoured to procure torches, but was obliged to consider myself fortunate in getting a few tapers. It is necessary to provide oneself with torches at Reikjavik. The parts of the cavern beneath the open craters were still covered with a considerable quantity of snow, by which our progress was rendered very dangerous. We frequently sunk in, and at other times caught our feet between the stones, so that we could scarcely maintain our balance. In the by-paths situated near these openings an icy rind had formed itself, which was now covered with water. Farther on, the ice had melted; but it was generally very dirty, as a stratum of sand mixed with water lay there in place of the stones. The chief path alone was covered with blocks of lava; in the smaller paths I found only strata of sand and small pieces of lava. The magical illumination produced by the sun's rays shining through one of these craters into the cavern produced a splendid effect. The sun shone perpendicularly through the opening, spread a dazzling radiance over the snow, and diffused a pale delicate light around us. The effect of this point of dazzling light was the more remarkable from its contrasting strongly with the two dark chasms, from the first of which we had emerged to continue our journey through the obscurity of the second. This subterranean labyrinth is said to extend in different directions for many miles. We explored a portion of the chief path and several by-paths, and after a march of two hours returned heartily tired to the upper world. We then rested a quarter of an hour, and afterwards returned at a good round pace to Kalmannstunga.