To this unexpected revelation Dick Sand could not reply. Besides, Mrs.
Weldon had gone back at once to her place beside little Jack. She
evidently did not wish to say any more about it, and the young novice
had not the courage to detain her.

Thus Mrs. Weldon knew what to believe. The various incidents, of the
way had enlightened her also, and perhaps, too, that word, "Africa!"
so unluckily pronounced the night before by Cousin Benedict.

"Mrs. Weldon knows everything," repeated Dick Sand to himself. "Well,
perhaps it is better so. The brave woman does not despair. I shall not
despair either."

Dick Sand now longed for day to return, that he might explore the
surroundings of this termite village. He must find a tributary of the
Atlantic with a rapid course to transport all his little troop. He had
a presentiment that this watercourse could not be far distant. Above
all, they must avoid an encounter with the natives, perhaps already
sent in pursuit of them under Harris’s and Negoro’s direction.

But it was not day yet. No light made its way into the cone through
the lower orifice. Rumblings, rendered low by the thickness of the
walls, indicated that the storm still raged. Listening, Dick Sand also
heard the rain falling with violence at the base of the ant-hill. As
the large drops no longer struck a hard soil, he must conclude that
the whole plain was inundated.

It must have been about eleven o’clock. Dick Sand then felt that a
kind of torpor, if not a true sleep, was going to overcome him. It
would, however, be rest. But, just as he was yielding to it, the
thought came to him that, by the settling of the clay, washed in, the
lower orifice was likely to be obstructed. All passage for the outer
air would be closed. Within, the respiration of ten persons would soon
vitiate the air by loading it with carbonic acid.

Dick Sand then slipped to the ground, which had been raised by the
clay from the first floor of cells.

That cushion was still perfectly dry, and the orifice entirely free.
The air penetrated freely to the interior of the cone, and with it
some flashes of lightning, and the loud noises of that storm, that a
diluvian rain could not extinguish.

Dick Sand saw that all was well. No immediate danger seemed to menace
these human termites, substituted for the colony of newroptera. The
young novice then thought of refreshing himself by a few hours’ sleep,
as he already felt its influence. Only with supreme precaution Dick
Sand lay on that bed of clay, at the bottom of the cone, near the
narrow edifice.

By this means, if any accident happened outside, he would be the first
to remark it. The rising day would also awaken him, and he would be
ready to begin the exploration of the plain.

Dick Sand lay down then, his head against the wall, his gun under his
hand, and almost immediately he was asleep.

How long this drowsiness lasted he could not tell, when he was
awakened by a lively sensation of coolness.

He rose and recognized, not without great anxiety, that the water was
invading the ant hill, and even so rapidly, that in a few seconds it
would reach the story of cells occupied by Tom and Hercules.

The latter, awakened by Dick Sand, were told about this new
complication.

The lighted lantern soon showed the interior of the cone.

The water had stopped at a height of about five feet, and remained
stationary.

"What is the matter, Dick?" asked Mrs. Weldon.

"It is nothing," replied the young novice. "The lower part of the
cone has been inundated. It is probably that during this storm a
neighboring river has overflowed on this plain."

"Good!" said Hercules; "that proves the river is there!"

"Yes," replied Dick Sand, "and it will carry us to the coast. Be
reassured, then, Mrs. Weldon; the water cannot reach you, nor little
Jack, nor Nan, nor Mr. Benedict."

Mrs. Weldon did not reply. As to the cousin, he slept like a veritable
termite.

Meanwhile the blacks, leaning over this sheet of water, which
reflected the lantern’s light, waited for Dick Sand to indicate
to them what should be done. He was measuring the height of the
inundation.

After having the provisions and arms put out of the reach of the
inundation, Dick Sand was silent.

"The water has penetrated by the orifice," said Tom.

"Yes," replied Dick Sand, "and now it prevents the interior air from
being renewed."

"Could we not make a hole in the wall above the level of the water?"
asked the old black.

"Doubtless, Tom; but if we have five feet of water within, there are
perhaps six or seven, even more, without."

"You think, Mr. Dick – ?"

"I think, Tom, that the water, rising inside the ant-hill, has
compressed the air in the upper part, and that this air now makes an
obstacle to prevent the water from rising higher. But if we pierce a
hole in the wall by which the air would escape, either the water would
still rise till it reached the outside level, or if it passed the
hole, it would rise to that point where the compressed air would again
keep it back. We must be here like workmen in a diving-bell."

"What must be done?" asked Tom.

"Reflect well before acting," replied Dick Sand. "An imprudence might
cost us our lives!"

The young novice’s observation was very true.

In comparing the cone to a submerged bell, he was right. Only in that
apparatus the air is constantly renewed by means of pumps. The divers
breathe comfortably, and they suffer no other inconveniences than
those resulting from a prolonged sojourn in a compressed atmosphere,
no longer at a normal pressure.

But here, beside those inconveniences, space was already reduced a
third by the invasion of the water. As to the air, it would only be
renewed if they put it in communication with the outer atmosphere by
means of a hole.

Could they, without running the danger spoken of by Dick Sand, pierce
that hole? Would not the situation be aggravated by it?

What was certain was, that the water now rested at a level which only
two causes could make it exceed, namely: if they pierced a hole, and
the level of the rising waters was higher outside, or if the height
of this rising water should still increase. In either of these cases,
only a narrow space would remain inside the cone, where the air, not
renewed, would be still more compressed.

But might not the ant-hill be torn from the ground and overthrown by
the inundation, to the extreme danger of those within it? No, no more
than a beaver’s hut, so firmly did it adhere by its base.

Then, the event most to be feared was the persistence of the storm,
and, consequently, the increase of the inundation. Thirty feet of
water on the plain would cover the cone with eighteen feet of water,
and bear on the air within with the pressure of an atmosphere.

Now, after reflecting well upon it, Dick Sand was led to fear that
this inundation might increase considerably.

In fact, it could not be due solely to that deluge poured out by
the clouds. It seemed more probable that a neighboring watercourse,
swelled by the storm, had burst its banks, and was spreading over this
plain lying below it. What proof had they that the ant-hill was not
then entirely submerged, and that it was full time to leave it by the
top part, which would not be difficult to demolish?

Dick Sand, now extremely anxious, asked himself what he ought to
do. Must he wait or suddenly announce the probable result of the
situation, after ascertaining the condition of things?

It was then three o’clock in the morning. All, motionless, silent,
listened. The noise from outside came very feebly through the
obstructed orifice. All the time a dull sound, strong and continued,
well indicated that the contest of the elements had not ceased.

At that moment old Tom observed that the water level was gradually
rising.

"Yes," replied Dick Sand, "and if it rises, as the air cannot escape
from within, it is because the rising of the waters increases and
presses it more and more."

"It is but slight so far," said Tom.

"Without doubt," replied Dick Sand; "but where will this level stop?"

"Mr. Dick," asked Bat, "would you like me to go out of the ant-hill?
By diving, I should try to slip out by the hole."

"It will be better for me to try it," replied Dick Sand.

"No, Mr. Dick, no," replied old Tom, quickly; "let my son do it, and
trust to his skill. In case he could not return, your presence is
necessary here."

Then, lower:

"Do not forget Mrs. Weldon and little Jack."

"Be it so," replied Dick Sand. "Go, then, Bat. If the ant-hill is
submerged, do not seek to enter it again. We shall try to come out as
you will have done. But if the cone still emerges, strike on its top
with the ax that you will take with you. We will hear you, and it
will be the signal for us to demolish the top from our side. You
understand?"

"Yes, Mr. Dick," replied Bat.

"Go, then, boy," added old Tom, pressing his son’s hand.

Bat, after laying in a good provision of air by a long aspiration,
plunged under the liquid mass, whose depth then exceeded five feet. It
was a rather difficult task, because he would have to seek the lower
orifice, slip through it, and then rise to the outside surface of the
waters.

That must be done quickly.

Nearly half a minute passed away. Dick Sand then thought that Bat had
succeeded in passing outside when the black emerged.

"Well!" exclaimed Dick Sand.

"The hole is stopped up by rubbish!" replied Bat, as soon as he could
take breath.

"Stopped up!" repeated Tom.

"Yes," replied Bat. "The water has probably diluted the clay. I have
felt around the walls with my hand. There is no longer any hole."

Dick Sand shook his head. His companions and he were hermetically
sequestered in this cone, perhaps submerged by the water.

"If there is no longer any hole," then said Hercules, "we must make
one."

"Wait," replied the young novice, stopping Hercules, who, hatchet in
hand, was preparing to dive.

Dick Sand reflected for a few moments, and then he said:

"We are going to proceed in another manner. The whole question is to
know whether the water covers the ant-hill or not. If we make a small
opening at the summit of the cone, we shall find out which it is. But
in case the ant-hill should be submerged now, the water would fill it
entirely, and we would be lost. Let us feel our way."

"But quickly," replied Tom.

In fact, the level continued to rise gradually. There were then six
feet of water inside the cone. With the exception of Mrs. Weldon,
her son, Cousin Benedict, and Nan, who had taken refuge in the upper
cavities, all were immersed to the waist.

Then there was a necessity for quick action, as Dick Sand proposed.

It was one foot above the interior level, consequently seven feet from
the ground, that Dick Sand resolved to pierce a hole in the clay wall.

If, by this hole, they were in communication with the outer air, the
cone emerges. If, on the contrary, this hole was pierced below the
water level outside, the air would be driven inward, and in that case
they must stop it up at once, or the water would rise to its orifice.
Then they would commence again a foot higher, and so on. If, at last,
at the top, they did not yet find the outer air, it was because there
was a depth of more than fifteen feet of water in the plain, and that
the whole termite village had disappeared under the inundation. Then
what chance had the prisoners in the ant-hill to escape the most
terrible of deaths, death by slow asphyxia?

Dick Sand knew all that, but he did not lose his presence of mind for
a moment. He had closely calculated the consequences of the experiment
he wished to try. Besides, to wait longer was not possible. Asphyxia
was threatening in this narrow space, reduced every moment, in a
medium already saturated with carbonic acid.

The best tool Dick Sand could employ to pierce a hole through the wall
was a ramrod furnished with a screw, intended to draw the wadding from
a gun. By making it turn rapidly, this screw scooped out the clay like
an auger, and the hole was made little by little. Then it would not
have a larger diameter than that of the ramrod, but that would be
sufficient. The air could come through very well.

Hercules holding up the lantern lighted Dick Sand. They had some wax
candles to take its place, and they had not to fear lack of light from
that source.

A minute after the beginning of the operation, the ramrod went freely
through the wall. At once a rather dull noise was produced, resembling
that made by globules of air escaping through a column of water. The
air escaped, and, at the same moment, the level of the water rose in
the cone, and stopped at the height of the hole. This proved that they
had pierced too low – that is to say, below the liquid mass.

"Begin again," the young novice said, coolly, after rapidly stopping
the hole with a handful of clay.

The water was again stationary in the cone, but the reserved space had
diminished more than eight inches. Respiration became difficult, for
the oxygen was beginning to fail. They saw it also by the lantern’s
light, which reddened and lost a part of its brightness.

One foot above the first hole, Dick Sand began at once to pierce a
second by the same process. If the experiment failed, the water would
rise still higher inside the cone – but that risk must be run.

While Dick Sand was working his auger, they heard Cousin Benedict cry
out, suddenly:

"Mercy! look – look – look why!"

Hercules raised his lantern and threw its light on Cousin Benedict,
whose face expressed the most perfect satisfaction.

"Yes," repeated he, "look why those intelligent termites have
abandoned the ant-hill! They had felt the inundation beforehand. Ah!
instinct, my friends, instinct. The termites are wiser than we are,
much wiser."

And that was all the moral Cousin Benedict drew from the situation.

At that moment Dick Sand drew out the ramrod, which had penetrated the
wall. A hissing was produced. The water rose another foot inside the
cone – the hole had not reached the open air outside.

The situation was dreadful. Mrs. Weldon, then almost reached by the
water, had raised little Jack in her arms. All were stifling in this
narrow space. Their ears buzzed.

The lantern only threw a faint light.

"Is the cone, then, entirely under water?" murmured Dick Sand.

He must know; and, in order to know, he must pierce a third hole, at
the very top.

But it was asphyxia, it was immediate death, if the result of this
last attempt should prove fruitless. The air remaining inside would
escape through the upper sheet of water, and the water would fill the
whole cone.

"Mrs. Weldon," then said Dick Sand, "you know the situation. If we
delay, respirable air will fail us. If the third attempt fails, water
will fill all this space. Our only chance is that the summit of the
cone is above the level of the inundation. We must try this last
experiment. Are you willing?"

"Do it, Dick!" replied Mrs. Weldon.

At that moment the lantern went out in that medium already unfit for
combustion. Mrs. Weldon and her companions were plunged in the most
complete darkness.

Dick Sand was perched on Hercules’s shoulders. The latter was hanging
on to one of the lateral cavities. Only his head was above the bed of
water.

Mrs. Weldon, Jack, and Cousin Benedict were in the last story of
cells.

Dick Sand scratched the wall, and his ramrod pierced the clay rapidly.
In this place the wall, being thicker and harder also, was more
difficult to penetrate. Dick Sand hastened, not without terrible
anxiety, for by this narrow opening either life was going to penetrate
with the air, or with the water it was death.

Suddenly a sharp hissing was heard. The compressed air escaped – but a
ray of daylight filtered through the wall. The water only rose eight
inches, and stopped, without Dick Sand being obliged to close the
hole. The equilibrium was established between the level within and
that outside. The summit of the cone emerged. Mrs. Weldon and her
companions were saved.

At once, after a frantic hurra, in which Hercules’s thundering voice
prevailed, the cutlasses were put to work. The summit, quickly
attacked, gradually crumbled. The hole was enlarged, the pure air
entered in waves, and with it the first rays of the rising sun. The
top once taken off the cone, it would be easy to hoist themselves on
to its wall, and they would devise means of reaching some neighboring
height, above all inundations.

Dick Sand first mounted to the summit of the cone.

A cry escaped him.

That particular noise, too well known by African travelers, the
whizzing of arrows, passed through the air.

Dick Sand had had time to perceive a camp a hundred feet from the
ant-hill, and ten feet from the cone, on the inundated plain, long
boats, filled with natives.

It was from one of those boats that the flight of arrows had come the
moment the young novice’s head appeared out of the hole.

Dick Sand, in a word, had told all to his companions. Seizing his gun,
followed by Hercules, Acteon, and Bat, he reappeared at the summit of
the cone, and all fired on one of the boats.

Several natives fell, and yells, accompanied by shots, replied to the
detonation of the fire-arms.

But what could Dick Sand and his companions do against a hundred
Africans, who surrounded them on all sides?

The ant-hill was assailed. Mrs. Weldon, her child, and Cousin
Benedict, all were brutally snatched from it, and without having had
time to speak to each other or to shake hands for the last time, they
saw themselves separated from each other, doubtless in virtue of
orders previously given.

A last boat took away Mrs. Weldon, little Jack and Cousin Benedict.
Dick Sand saw them disappear in the middle of the camp.

As to him, accompanied by Nan, Old Tom, Hercules, Bat, Acteon and
Austin, he was thrown into a second boat, which went toward another
point of the hill.

Twenty natives entered this boat.

It was followed by five others.

Resistance was not possible, and nevertheless, Dick Sand and his
companions attempted it. Some soldiers of the caravan were wounded
by them, and certainly they would have paid for this resistance with
their lives, if there had not been a formal order to spare them.

In a few minutes, the passage was made. But just as the boat landed,
Hercules, with an irresistible bound, sprang on the ground. Two
natives having sprung on him, the giant turned his gun like a club,
and the natives fell, with their skulls broken.

A moment after, Hercules disappeared under the cover of the trees,
in the midst of a shower of balls, as Dick Sand and his companions,
having been put on land, were chained like slaves.