Over this great volcanic mole or offset, we proceeded to make our way toward the caldron in the southeast, pounding before us with our pole, like men crossing a river to find whether the ice ahead will bear them. We stopped every now and then to examine and get up on to some great cone or oven, which had been formed after the congelation of the crust, by pent up gas blowing out from beneath the cooling lava, raising it as in great bubbles, and letting its black, viscous vomit dribble from the top, and flow down sluggishly and congeal before it had found a level, like ice in very cold weather over a waterfall. Thus it would flow over the Black Ledge, hardening sometimes in round streams like a cable, or in serpentine forms like a great anaconda; and again it would spread out from the foot of the cone a little way, in forms like a bronze lion's foot.
The surface was frequently broken, or ready to break, with the weight of one's body, from the fiery liquid having subsided after the petrifaction of the crust. Generally, too, the hardened lava seemed to have been flowed over, like ice near the shore when the tide rises and goes down, with a thin scum of lava that became shelly and crepitated under the foot like shelly ice.
Then, as we went further into the bed of the crater, gradually going down, we would come to places where, like as in frozen mill-ponds, whence the water has been drawn off, the congealed lava had broken in to the depth sometimes of fifty and one hundred feet. Every where, too, there were great fissures and cracks, as in fields of river ice, now and then a large air-hole, and here and there great bulges and breaks, and places from which a thin flame would be curling, or over which you would see a glimmer like that which trembles over a body of fresh coals or a recently-burned lime-kiln. Touch your stick there, and it would immediately kindle.
There were also deep, wide ditches, through which a stream of liquid lava had flowed since the petrifaction of the main body through which it passed. Cascades of fire are said to be often seen in the course of these canals or rivers as they leap some precipice, presenting in the night a scene of unequaled splendor and sublimity. In some places the banks or dikes of these rivers are excavated and fallen in with hideous crash and ruin; and often you may go up, if you dare, to the edge on one side and look over into the gulf, and away under the opposite overhanging bank, where the igneous fluid has worn away and scooped it out till the cliff hangs on air, and seems to topple and lean, like the tower of Pisa, just ready to fall.
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.
Again, when Mr. Bingham was there, it was full, and concentric waves were flowing out and around from its centre. Having carefully observed its movements a while, he threw a stick of wood upon the thin crust of a moving wave where he thought it would bear him, even if it should bend a little, and then stood upon it a few moments. In that position, thrusting his cane down through the cooling tough crust, about half an inch thick, and immediately withdrawing it, forthwith there gushed up, like ooze in a marsh or melted tar under a plank, enough of the viscid lava to form a globular mass, which afterward, as it cooled, he broke off and bore away.
It is not easy for one that has not himself been in a similar position, to sympathize with and pardon the traveler at such a point, for he is unwilling to forbear and leave it till fairly surfeited and seared with heat and admiration, or driven off by some sudden spout and roar, or splash of the caldron. You gaze, and gaze, and gaze in amazement, without conscious thought, like a man in a trance, reluctant to go away, and you want to spend at least a day and night, viewing close at hand its ever-varying phenomena.
Had we only brought with us wrappers, I believe we should