ack
folds, and sometimes rolled down the sides of the cone, and hid
the crest from view. Michael Angelo expressed a fear that they
would not be able to reach the crest; and as they drew nearer,
every step showed that this fear was well founded. At last, when
they were within easy distance of it, there came rolling down a
cloud of smoke, so dense and so full of sulphurous vapor that they
all had to stop and cover their faces with their clothes.

It was now evident that they could go no farther. They waited for
a time in great distress from the smoke. It rolled away at last,
yet still hovered near them, every little while moving threateningly
down, as though to drive them back, and prevent the crater from
desecration by human footsteps. They had evidently reached their
farthest limit, and could go no farther.

But where was Bob?

Scarcely had they discovered the impossibility of going farther
than this thought came to them. Where was Bob? He had left them
some time previously, and had gone far ahead of them. They had
expected every moment to come up with him. But there were no signs
of him anywhere.

Frank called out with all his strength. David and Clive joined in
the cry.

There was no response.

Fear came to them--a sickening, awful fear. All shouted--the boys,
Uncle Moses, and Michael Angelo.

Still there was no response.

Again, and again, and yet again, they called, by this time in an
agony of apprehension; but to all these cries the surrounding
stillness gave forth not one answering sound.

And the deep, dark, wrathful smoke-clouds rolled around, and above,
and downward, moving close to them, and over them, as though eager
to involve them in that dread fate which they feared had overwhelmed
the lost boy.

"I can't stand this any longer!" cried Frank, at last. "I'll go
and hunt him up."

"We'll all go," said David.

"Wait," said Uncle Moses, as the boys were starting. "We must hunt
him up as we do in the woods. We can't tell where he is. Let's form
a line, an walk as nigh abreast of one another as we can get, an
yet far enough away to cover the ground. In that way well be more
likely to find him."

At this the party formed themselves in a line, so that about twenty
or thirty feet intervened between each. The five thus extended for
a long distance. Michael Angelo was at the extreme right, next to
him was Uncle Moses, then Clive, then David, while Frank was on
the extreme left. In this way they de