So saying he glided past his comrade, and was almost lost to sight immediately in the deep gloom.
“Softly, softly, doctor,” whispered the seaman, as he followed, “there may be holes or pits within—”
“All right; I’m feeling my way carefully. Keep close.”
As he spoke a slight, indescribable sound was heard—almost like a sigh.
“Hist! Did ’ee hear that?” said Hockins in the lowest possible whisper.
“Oh! massa, let’s go back de way we come,” urged Ebony, in the same low but earnest tone.
Mark Breezy did not reply, but the click of his gun as he cocked it showed that he was on the alert.
For nearly a minute the three men stood in absolute silence, listening for a repetition of the mysterious sound, and, though it did not recur, there was an indescribable feeling in the heart of each that they were not alone in that cavern.
“Have you not flint and steel?” asked Mark.
“Yes; but to strike a light would only show our whereabouts if there is any one here.”