Chapter 6 - The Diving-Bell
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."
"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.