It was an exploit that required considerable agility; the diver would have to find the orifice, make his way through it, and, without loss of a moment, let himself rise to the surface outside. Full half a minute elapsed, and Dick was making sure that the negro had been successful in his effort, when his black head emerged from the water. There was a general exclamation of surprise.
"It is blocked up," gasped Bat, as soon as he had recovered breath enough to speak.
"Blocked up?" cried Tom.
"Yes," Bat affirmed; "I have felt all round the wall very carefully with my hand, and I am sure there is no hole left; I suppose the water has dissolved the clay."
"If you cannot find a hole," exclaimed Hercules, "I can very soon make one;" and he was just about to plunge his hatchet into the side of the ant-hill, when Dick prevented him.
"Stop, stop! you must not be in such a hurry!"
He reflected for a few moments, and went on,-
"We must be cautious; an impetuous step may be destruction; perhaps the water is over the top; if it is allowed to enter, then at once is an end of all."
"But whatever we do," urged Tom, "must be done at once; there is no time to lose."
He was right; the water had risen till it was quite six feet deep; none but Mrs. Weldon, Jack, Nan, and Cousin Benedict, who were lodged in the upper cells, were fairly above its surface.