“Hark!” was the only reply vouchsafed by Frank.
As he spoke he poked at the floor of the cave with the tip of his shoe and dislodged a stone. He gave it a kick forward and the boys, with tingling scalps and a cold shudder down their spines, heard it plunge down—down into unknown depths till the sound died out in a tiny tinkle, and all was silent as a tomb again.
“Phew!” gasped Harry, “that was a narrow escape, how did you detect it, Frank?”
“I came pretty near not discovering it in time,” laughed the young leader, who now that the danger was over was busy holding his candle at every angle to see what their surroundings might be, “as luck would have it, however, my foot dislodged a small pebble just as I was about to step over into what would have been eternity. I heard it drop down just as you fellows heard the larger one. I guess we’ll have to thank that little bit of stone for saving the life of one of us at any rate.”
“Let’s light up and see where we are?” suggested Harry, after the boys, fascinated by the mystery of the vanishing sound, had hurled dozens of rocks into the depths.
“I hate to squander the candles, but I suppose we’ll have to,” replied Frank. “This one of mine doesn’t come near lighting up the place.”
A simultaneous gasp came from the boys as, with all three candles lighted, they peered over into the black gulf that yawned at their feet. It was a huge fissure, possibly twelve feet across, and of unknown depth. It reached clear from wall to wall of the passage, which at this point had broadened out into what Harry called “a regular Council Chamber.” As if to verify his words the light of the boys’ combined candles revealed that the walls were carved with countless figures of quesals and other hieroglyphics intended apparently to typify the ceremony of the sacrifice. Dust and time, however, had done their work, and in many places the figures were chipped away altogether where the rock had flaked off.
At the further side of the chasm they could make out a spot of darker black against the inky surface of the rock which Frank rightly took to be the mouth of a continuation of the tunnel.
“Look here, boys” he cried in excitement, pointing across the abyss at the darker shading that marked the mouth of the entrance of the extension of the passage they had already traversed. “Do you know what that means?”
“Well, I suppose it’s another tunnel, but what good does that do us,” grumbled Harry; “unless we can jump this little ditch ahead of us?”