Another moment and there came a mighty roar.  Up went the mud-lake hundreds of feet into the air; out came the steam with the sound of a thousand trombones, and away went the two porters, head ever heels, down the outer slope of the cone and across the sawah as if the spirit of evil were after them.

There was no cause, however, for alarm.  The mud-lake, falling back into its native cup, resumed its placid aspect and awaited its next upheaval with as much tranquillity as if it had never known disturbance in the past, and were indifferent about the future.

That evening our travellers encamped in close proximity to the crater, supped on fowls roasted in an open crevice whence issued steam and sulphurous smells, and slept with the geyser’s intermittent roar sounding in their ears and re-echoing in their dreams.

CHAPTER XXIII.

TELLS OF VOLCANIC FIRES AND A STRANGE RETURN “HOME.”

This tremendous introduction to volcanic fires was but the prelude to a period of eruptive action which has not been paralleled in the world’s history.

For a short time after this, indeed, the genial nature of the weather tended to banish from the minds of our travellers all thoughts of violence either in terrestrial or human affairs, and as the professor devoted himself chiefly to the comparatively mild occupation of catching and transfixing butterflies and beetles during the march southward, there seemed to be nothing in the wide universe above or below save peace and tranquillity—­except, perhaps, in the minds of beetles and butterflies!

Throughout all this period, nevertheless, there were ominous growlings, grumblings, and tremors—­faint but frequent—­which indicated a condition of mother earth that could not have been called easy.

“Some of the volcanoes of Java must be at work, I think,” said Nigel one night, as the party sat in a small isolated wood-cutter’s hut discussing a supper of rice and fowls with his friends, which they were washing down with home-grown coffee.

“It may be so,” said Van der Kemp in a dubious tone; “but the sounds, though faint, seem to me a good deal nearer.  I can’t help thinking that the craters which have so recently opened up in Krakatoa are still active, and that it may be necessary for me to shift my quarters, for my cave is little more, I suspect, than the throat of an ancient volcano.”

“Hah! say you so, mine frond?  Zen I vould advise you to make no delay,” said the professor, critically examining a well-picked drumstick.  “You see, it is not pleasant to be blown up eizer by the terrestrial eruptions of zee vorld or zee celestial explosions of your vife.—­A leetle more rice, Moses if you please.  Zanks.”

“Now, mine fronds,” he continued, after having disposed of a supper which it might have taxed a volcano’s throat to swallow, “it is viz great sorrow zat I must part from you here.”