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.