"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