“This cave is alive,” he added. “You see the mark of the feets?”
“Where is Mr. Arthur?” suddenly asked Una.
They had been so absorbed in the mystery of the vanishing tunnel that the absence of one of their number had not been noticed. Una’s startled query brought them face to face with another puzzle, as baffling and uncanny, in a way, as the wall of rock that had come from nowhere and planted itself between them and the entrance to the cave. Raoul had disappeared; search as they might, call as loudly as they could, no trace of him was to be found. Had he deliberately deserted them, or had he suddenly been spirited away by the same invisible agency that had prevented their leaving the cave? The more credulous of the party believed he had been spirited away.
“But it is impossible,” insisted Miranda angrily. “I see him now—and now he is not here. The canaille!”
“There is only one thing to be done,” declared Leighton emphatically. “We can’t get out of here; we must go on.”
“Yes! Yes!” exclaimed Una.
“Caramba! What for we go on?” remonstrated Miranda. “We are lost, we starve, if we leave this place.”
“You mean, we are lost if we stay here,” reasoned Leighton. “There is nothing to be gained by staring at this rock. The fact that Arthur has disappeared, that the entrance to the tunnel has been closed, that there are fresh footprints besides our own all about us, proves that this cave is inhabited. Whoever they are, we must find these people.”
Leighton’s way of putting things was effective. It at least prevented a panic. Even Miranda admitted the necessity of the course proposed by the savant, and as Herran had nothing else to offer in its place, it was decided to press on with the exploration of the cave without delay.