It was to the edge of one of these craters that the party now advanced, and the engraving will give you some idea of the view which it presented.
[Illustration: VIEW OF THE CRATER.]
There were several persons, both ladies and gentlemen, standing on the margin of the crater when our party arrived. Mr. George led Rosie to the place, and looked down with her into the abyss. The sides of it were formed of precipitous cliffs of rocks and sand, all beautifully colored, in every shade of red and yellow, by the deposits of sulphur which had accumulated upon them from the fumes of the volcano. The floor of the crater was black as jet, being covered by the molten lava, which had gradually spread over it. The surface of this lava lay in wave-like corrugations, like the hide of a rhinoceros, showing that it was or had been semi-fluid. In the centre rose a great, black, rounded cone, like the cupola of an immense blast furnace. This cone was about fifty feet high, and there was an opening at the top eight or ten feet in diameter, which glowed with a furious heat, and emitted quietly, but continually, a red-hot breath of sulphurous vapor.
After remaining thus quiet for a few moments, suddenly it would give a gasp, and immediately afterwards there would burst forth a thundering explosion, which seemed to come up from a great depth below, and threw into the air a shower of stones and scraps of molten lava, which, after ascending to a great height, came down again, and fell, with a dripping sound, upon and around the cone. Similar explosions occurred at intervals of a few minutes, all the time that the party remained.
Rosie was at first very much afraid of these explosions, and she wished to go back. Mr. George himself was also afraid at first to stand very near the edge of the crater; but it was not on account of the explosions, but for fear that the cliff might cave in. Indeed, the cliffs all around were cracked off, and in some places leaning over, apparently ready to fall; and even at the spot where the spectators stood looking into the crater, there was a fissure running along parallel to the cliff, some feet behind them. At first Mr. George was afraid to step over this crack.
"How do they know," said he to himself, "but that the whole mass will fall and carry them all down into the gulf below?"
He found, however, after waiting a little while, that it did not fall, and there were besides other masses a little farther along, as seen in the engraving, which had become separated entirely from the cliff behind them, leaving a chasm open two or three feet wide; and yet they did not fall. So Mr. George gradually acquired more confidence, and at length went cautiously forward, and looked over the brink.
Rosie, however, hung back. She was alarmed to see Rollo and Josie go so near.
"Come back, Josie," said she; "come back. You must not go so near."
So Mr. George called the boys back, and they obeyed.
The walls of this crater were on every side almost perpendicular. As the central part had gradually sunk, the sides had caved off and fallen in, and then afterwards the lava that had been thrown up had spread over the floor, and covered it with a bed of a half-fluid looking substance, that was as black as pitch, and which, though it was really now pretty hard, looked as if a stone thrown down upon it would sink immediately into it, out of sight.
The crater seemed to be four or five hundred feet across, and the walls of it were eighty or a hundred feet high.
After Mr. George and the children had been standing upon the brink of this abyss some time, watching the explosions, the guide who had come up with them from the Hermitage beckoned to Mr. George, and saying something at the same time in Italian, made signs as if he wished the party to go with him to some other place.
"Come, boys," said Mr. George; "he wants us to go with him."
"Where does he want us to go?" asked Rollo.
"I don't know," said Mr. George. "I cannot understand what he says; but let us go and see."
So the whole party followed the guide, Mr. George leading Rosie by the hand. The guide conducted them along a narrow path through the sand, which led away from the crater behind a hill which formed one of the sides of it at a place where it was so steep below the path down the mountain side, that Rosie was almost afraid to go. Mr. George, however, held her firmly by the hand, and he charged Rollo and Josie to follow very carefully. After going on in this way for some distance, they came to another crater very similar to the first, only the sides of it, instead of being formed, like the first, of perpendicular cliffs, consisted of steep, sloping banks of volcanic sand and gravel. There was, however, the same pitchy bed of lava spread out all over the bottom of it below, and in the centre a black cone thirty feet high, with a fiery furnace mouth at the top, glowing with heat, and throwing out continually the same thundering puffs of steam, and projecting the same masses of melted lava and hot stones into the air.
"Ah, here is another crater!" said Mr. George.
"Yes," said Rollo; "only it is smaller than the first. I like the first the best."
While they were standing on the narrow ridge which formed the brink of the crater, looking down, their guide by their side, another guide came by, conducting two young men; and they, instead of stopping on the brink, as Mr. George and his party had done, began at once to go down. There was a sort of track in the sand down the slope, and in this track the young men, half walking, half sliding, descended.
"Why, uncle George!" exclaimed Rollo, "they are going down into the crater. Let Josie and me go too."
Mr. George saw by a glance that the descent into the crater must be safe, for the young men were led by one of the regular mountain guides; and besides, there was a track in the sand, showing that other parties had gone down before. So he said that Rollo and Josie might go.
"You may go down with this party," said Mr. George, "and then you can come up and take care of Rosie while I go down with our guide."
So Rollo and Josie followed the two young men down. Mr. George watched them from above. They went down very easily, for the sand was soft, and the track turned this way and that, so as to avoid the steepest places. The black lava covered the whole floor of the crater, and Mr. George and Rosie supposed that those who had gone down would be able only to go to the edge of it; but, to their great surprise, they found that the guide, as soon as he reached it, stepped upon it, and walked boldly out, followed by the young men and by Rollo and Josie, like a party of boys walking out upon the ice on a pond.
"Why, uncle George!" exclaimed Rosie, "they are walking over the lava. Why don't they sink in?"
"I cannot imagine," said Mr. George. "I supposed it was soft."
In fact, it was soft; that is, it was soft enough to flow if it had been on a slope, but yet it was hard enough to walk upon. A current of lava, when it is coming down the mountain side, can often be walked upon while it is still in motion. Its fluidity at the best is very imperfect, and its motion is very slow. The lava which Rollo was upon in the floor of the crater, though pretty nearly cool and hard on the surface, was hot below. Rollo could see the redness of the heat in the holes and crevices. Probably, if a heavy stone were laid upon the bed of lava, it would gradually have sunk into it. And yet persons could walk over it without any difficulty.
Rollo and Josie followed the young men over the lava until they came so near the cone in the centre that if they were to advance farther they would be in danger of having the lava which was thrown up from it fall upon their heads. Here they found some boys, who belonged to the mountain, engaged in getting out small pieces of the lava, where it was hot and soft, and pressing coins into it, to sell to the people above. Rollo and Josie bought some of these specimens of the boys, and put them hot in their pockets.