On the 4th of January, by persevering industry, the process
of boring was completed, and the
lieutenant could hear that
fragments of the blasted rock, as the sailors cleared them away
with their spades, were rolling into the
funnel of the
crater.
He noticed, too, that they did not fall perpendicularly,
but seemed to slide along, from which he inferred that the sides
of the
crater were sloping; he had
therefore reason to hope
that a
descent would be found practicable.
Larger and larger grew the
orifice; at length it would admit a man's body,
and Ben Zoof, carrying a torch, pushed himself through it, followed by
the
lieutenant and Servadac. Procope's
conjecture proved correct.
On entering the
crater, they found that the sides slanted at the angle
of about 4 degrees ;
moreover, the
eruption had
evidently been of
recent
origin, dating probably only from the shock which had invested
Gallia with a
proportion of the
atmosphere of the earth, and beneath
the coating of ashes with which they were covered, there were various
irregularities in the rock, not yet worn away by the action of the lava,
and these afforded a tolerably safe footing.
"Rather a bad staircase!" said Ben Zoof, as they began to make
their way down.
In about half an hour,
proceeding in a southerly direction,
they had descended nearly five hundred feet. From time
to time they came upon large excavations that at first sight
had all the appearance of galleries, but by waving his torch,
Ben Zoof could always see their
extreme limits, and it was
evident that the lower strata of the mountain did not present
the same
system of ramification that rendered the Hive above
so commodious a
residence.
It was not a time to be fastidious; they must be satisfied
with such
accommodation as they could get, provided it was warm.
Captain Servadac was only too glad to find that his hopes
about the temperature were to a certain
extent realized.
The lower they went, the greater was the diminution in the cold,
a diminution that was far more rapid than that which is
experienced in making the
descent of terrestrial mines.
In this case it was a
volcano, not a colliery, that was
the object of
exploration, and
thankful enough they were
to find that it had not become
extinct. Although the lava,
from some unknown cause, had ceased to rise in the
crater,
yet
plainly it existed somewhere in an incan
descent state,
and was still transmitting
considerable heat to
inferior strata.
Lieutenant Procope had brought in his hand a mercurial
thermometer,
and Servadac carried an aneroid barometer, by means of which he could estimate
the depth of their
descent below the level of the Gallian Sea. When they
were six hundred feet below the
orifice the
mercury registered a temperature
of 6 degrees below zero.
"Six degrees!" said Servadac; "that will not suit us.
At this low temperature we could not
survive the winter.
We must try deeper down. I only hope the ventilation
will hold out."
There was, however, nothing to fear on the score of ventilation.
The great current of air that rushed into the
aperturepenetrated everywhere,
and made
respirationperfectly easy.
The
descent was continued for about another three hundred feet,
which brought the explorers to a total depth of nine hundred feet from
their old quarters. Here the
thermometer registered 12 degrees above zero--
a temperature which, if only it were
permanent, was all they wanted.
There was no
advantage in
proceeding any further along the lava-course;
they could already hear the dull rumblings that indicated that they
were at no great distance from the central focus.
"Quite near enough for me!" exclaimed Ben Zoof. "Those who