It would be no very comfortable reflection, if a man were not too curiously eager and bold and intent upon the novelties he is drinking in by the senses, to have much reflection or fear at such a time, to think how easily an earthquake might tumble down the bank on which he is standing, undermined in like manner with that which you are looking at right opposite.
On our left, as we passed on to the Great Caldron, we explored, as far as was possible between the heat and vapor, the great bank, or, more properly, mountain-side of sulphur and sulphate of lime (plaster of Paris), and obtained some specimens of no little beauty. There are cliffs of sulphur through which scalding hot vapor is escaping as high up above you as eight hundred feet; and lower down there are seams from which lambent and flickering flames are darting, and jets of hot air will sometimes whirl by you, involving no little danger by their inhalation. Around these fissures are yellow and green incrustations of sulphur, which afford a new variety of specimens.
When we had got to the leeward of the caldron, we found large quantities of the finest threads of metallic vitrified lava, like the spears and filaments of sealing-wax, called Pele's hair. The wind has caught them from the jets and bubbling springs of gory lava, and carried them away on its wings till they have lodged in nests and crevices, where they may be collected like shed wool about the time of sheep-shearing. Sometimes this is found twenty miles to the leeward of the volcano.
The heat and sulphur gas, irritating the throat and lungs, are so great on that side, that we had to sheer away off from the brim of the caldron, and could not observe close at hand the part where there was the most gushing and bubbling of the ignifluous mineral fluid. But we passed round to the windward, and were thus enabled to get up to the brim so as to look over for a minute in the molten lake, burning incessantly with brimstone and fire—
"A furnace formidable, deep, and wide,
O'erboiling with a mad, sulphureous tide."
But the lava which forms your precarious foothold, melted, perhaps, a hundred times, can not be handled or trusted, and the heat even there is so great as to burn the skin of one's face, although the heated air, as it rises, is instantly swept off to the leeward by the wind. It is always hazardous, not to say fool-hardy, to stand there for a moment, lest your uncertain foothold, crumbling and crispy by the action of fire, shall suddenly give way and throw you instantly into the fiery embrace of death.
At times, too, the caldron is so furiously boiling, and splashing, and spitting its fires, and casting up its salient, angry jets of melted lava and spume, that all approach to it is forbidden. We slumped several times near it, as a man will in the spring who is walking over a river of which the ice is beginning to thaw, and the upper stratum, made of frozen snow, is dissolved and rotten. A wary native who accompanied us wondered at our daring, and would not be kept once from pulling me back, as with the eager and bold curiosity of a discoverer, all absorbed in the view of such exciting wonders, I was getting too near.
At the time we viewed it, the brim all round was covered with splashes and spray to the width of ten or twelve feet. The surface of the lake was about a mile in its longest diameter, at a depth of thirty or forty feet from its brim, and agitated more or less all over, in some places throwing up great jets and spouts of fiery red lava, in other places spitting it out like steam from an escape-pipe when the valves are half lifted, and again squirting the molten rock as from a pop-gun.
The surface was like a river or lake when the ice is going out and broken up into cakes, over which you will sometimes see the water running, and sometimes it will be quite hidden. In the same manner in this lake of fire, while its surface was generally covered with a crust of half-congealed, dusky lava, and raised into elevations, or sunk into depressions, you would now and then see the live coal-red stream running along. Two cakes of lava, also, would meet like cakes of ice, and their edges crushing, would pile up and fall over, precisely like the phenomena of moving fields of ice; there was, too, the same rustling, grinding noise.
Sometimes, I am told, the roar of the fiery surges is like the heavy beating of surf. Once, when Mr. Coan visited it, this caldron was heaped up in the middle, higher above its brim than his head, so that he ran up and thrust in a pyrometer, while streams were running off on different sides. At another time when he saw it, it had sunk four or five hundred feet below its brim, and he had to look down a dreadful gulf to see its fires.