"I reckon it's a long sight more fortunate that they came along in the daytime," commented Emu Bill, "which they likely wouldn't have done, if they had thought we were about. Seems to me, that good Samaritan job o' ours in planting them nigs nice and comfortable out in the sand has done us a service right away."
"You've hit it pretty near, Bill," Bob agreed. "If they had done that trick in the night, we should probably have been wiped out."
"This is a mighty unpleasant climate for us tender lambs, it is," wailed the Shadow. "There's nary night but what we may wake up wi' a screech an' find ourselves dead."
"There's one way we can block it for good," muttered Mackay, grimly, "but I'm no vera willing to do it, for it will block us too, an' I mean to get inside that mountain before I'm a couple o' days older." He looked towards the gelignite case, lying near where it had been placed for safety, and his companions knew his plan at once. "Yes, we may well shoot down a bit o' the mountain big enough to bar that tunnel safe as a house, but that wouldn't suit us afterwards."
"If we roll round a few boulders wider than the door itself, that would keep things pretty safe for a night," suggested Jack; and in the end, this was the plan decided upon, and for half an hour they busied themselves transporting the most unwieldy diorite blocks they could find, and fixing them securely into the cavity. Then they returned to partake of their well-earned and belated dinner of tea and damper.
The last added proof of the blacks' ingenuity considerably disturbed the members of the little party. It had been so hard to believe that aborigines could possibly have constructed the tunnel through the mountain, but now they were inclined to imagine their savage neighbours capable of anything.
"I reckon we has got to go slow, boys," remarked Emu Bill, with a troubled expression; "them nigs don't seem to be the genuine article. They knows a long sight too much for my liking, they does."
Mackay, too, was obviously concerned. The mysterious tunnel mystified him; he could not imagine how it had been wrought, but there was gradually dawning in him a vastly increased respect for the natives who lived beyond the mountain. That they were different from all other tribes he had encountered was only too evident. The question was, in how great a degree did they excel their brethren of the plains? Judging from his brief experience of them, Mackay's estimate of their powers was far higher than he cared to admit.
"Of course," he said, in answer to Emu Bill, "if the country on the other side is what we expect, the natives will be of a much more advanced class than any we've met before. You see, it's the power o' environment, Bill; it may have worked marvels here, for a' we know."