“I will, on one condition.”

“And that is—?”

“That you also dispense with the ‘Mr.’ and ‘sir,’ and call me Van der Kemp.”

“Agreed,” said Nigel, “though it does not seem so appropriate in me as in you, considering the difference of our years.”

“Look here,” said the hermit, turning abruptly to a small wooden shed which had hitherto escaped the youth’s observation, so covered was it with overhanging boughs and tropical creeping plants, “these are my astronomical instruments.”

He pointed to a table in the hut on which stood several telescopes—­and microscopes as well—­one of the former being a large instrument, certainly not less than six feet long, with a diameter of apparently six or eight inches.

“Here, you see, I have the means of investigating the wonders of Nature in her grandest as well as her minutest scales.  And there,” he added, pointing to a couple of large reflecting mirrors in strong wooden frames, erected on joints in such a way that they could be turned in any direction,—­“there you have the secret of my sunshine.  One of these mirrors catches the sunshine direct and reflects it on the other, which, as you see, is so arranged that it transmits the rays down the natural funnel or chimney into the cave.  By means of chains connected with the mechanism, and extending below, I can change the direction of the mirrors as the sun changes its place in the sky, without requiring to come up here.”

“Very ingenious!” said Nigel; “but how do you manage when the mountain comes between you and the sun, as I see it cannot fail to do during some part of the day?”

“Simply enough,” returned the hermit, pointing to a distant projecting cliff or peak.  “On yon summit I have fixed four mirrors similar to these.  When the sun can no longer be reflected from this pair, the first of the distant mirrors takes it up and shoots a beam of light over here.  When the sun passes from that, the second mirror is arranged to catch and transmit it, and so on to the fourth.  After that I bid good-bye to the sun, and light my lamp!”

Nigel felt an almost irresistible tendency to smile at this, but the grave simplicity of the man forbade such familiarity.

“Look yonder,” continued the hermit, sweeping one of his long arms towards Sumatra, “in that direction runs the line of volcanic disturbance—­the fissure of which I have already spoken.  Focus this telescope to suit your sight.  Now, do you see the little island away there to the nor’-west?”

“Yes.”

“Well, that is Varlaten.  I mentioned it when at breakfast.  Sweep your glass round to the nor’ard, the little island there is Polish Hat, and you see Lang Island in the nor’-east.  These, with Krakatoa, are merely the higher parts still remaining above water of the ring or lip of the ancient crater.  This will give you some idea what an enormous mountain the original of this old volcano must have been.  This island-mountain is estimated to have been twenty-five miles in circumference, and 10,000 to 12,000 feet high.  It was blown into the air in 1680, and this island, with the few islets I have pointed out, is all that remains of it!  Now, cast your eye down the centre of the island on which we stand; you see several cones of various sizes.  These are ancient vents, supposed to be extinct—­”