ing 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,