"I know what you mean," he said; "but neither Jack nor I will leave unless we all leave together, so that if anything happened to you we would not escape in any case. Isn't it far better to make the most of our strength instead of dividing it?"
"Well, well, perhaps you are right," returned the big man, hastily, as if annoyed at his own fears; "but we'd better wait until morning before we start the circus. Like the Shadow, I prefer to meet the natives in daylight, and anyhow, we're a' needing a sleep to-night, so we'd be better to turn in early and get up by sunrise. It should take us a good half-hour in the morning blowing out that tunnel door for a start."
Certainly nothing further could be done on that day, for the darkness was already closing in, and each one of the party was weary and tired from lack of sleep. So shortly afterwards they lay down in their blankets, though not before a searching examination had been made of the new barricade erected at the entrance to the subterranean passage, and, in spite of the known dangers surrounding them, they slept soundly, each taking a two hours' watch in turn. It was well after midnight when Bob awoke for the first time, and at once his ears caught the strange tapping in the mountain which had first heralded the approach of the natives on the night before. He aroused himself immediately, and saw Mackay, who was on guard, listening to the ghostly echoes intently. Slowly they seemed to pass along the base of the hill, then all was quiet. Bob got up and joined Mackay, and together they walked softly towards the fissure, and there in the dull light they could vaguely see the great boulders move as if under pressure from beneath, but though they watched for fully ten minutes in silence, the barricade remained intact. Jack's scheme had worked admirably. Then Mackay turned on his heel with a loud laugh.
"It's just as well to let them ken we're here, Bob," he explained; and the sound of scurrying footsteps which answered him from the concealed passage showed that the natives had thought fit to retire once more. Then again the peculiar tapping issued out dully from the great rock, continuing for nearly a minute before it faded into the stillness of the night.
"Well, what do you make of it, Bob?" asked Mackay.
Bob did not hesitate a moment. "The passage must lead for some distance along the face of the mountain," said he. "But why these strange sounds are heard every time the blacks come along, I cannot say."
"Man, Bob," laughed Mackay, "that's vera easily explained. The tunnel must be dark, of course, and the warriors have to guide themselves along the passage by feeling the walls wi' their arrows or clubs as they go. It just struck me that that was the reason o' the uncanny noises when I heard them come along there to-night. Simple enough, isn't it, Bob?"
"I'm glad there is nothing approaching the supernatural about it, anyhow," replied Bob, soberly. "The echoes seemed to ring in my ears like a knell of doom."
He shuddered as he got back into his blanket. The others were awake by this time; but when they learned that an ineffective attempt had been made to destroy the barricade, they chuckled in rare good-humour, and went off to sleep again. The remainder of the night passed without alarm, and the morning broke, calm and serene, over the little camp, which awoke to life with renewed vigour after its peaceful slumber. Breakfast was soon over; then a hurried council of war was held to reason out the best plan of action. Emu Bill was in favour of inserting a heavy charge of gelignite in the rocking panel which had defied their gentler efforts on the preceding day; and Jack and the Shadow supported this proposal vociferously. Mackay, however, though he had at first advocated this drastic action, now seemed reluctant to carry it through; and Bob, too, though he did not say much, was evidently pondering over some other and better scheme, which he at last broached hesitatingly.
"If the passage runs parallel with the face of the mountain for twenty or thirty yards," he said, "it strikes me that if we made a fresh entrance to it as far away from the old one as possible, we could deceive the natives most completely, and perhaps provide a means of escape in an emergency."