Melton's hearing was unusually acute, for as yet the rest could hear nothing, but in a few seconds the distant roar was audible to all, and it grew ominously louder with every second.
They grasped the sides of the canoe in anxious suspense—for it was useless to paddle—and the angry waters were almost in sight, when Sir Arthur dropped his torch, and instantly they were plunged in total darkness.
No time remained to strike a fresh light. The sullen crash of the waters drowned the sound of their voices, and the canoe blindly took its own course and they felt the chill spray spattering their faces.
"Bump, bump, bump," went the quivering boat, grinding and crashing on loose rocks, and then with one terrific lurch, that sent them sprawling on their knees, the violent tossing subsided and the choppy waves smacked the bottom of the canoe.
With some difficulty Guy lit a fresh torch, and its light revealed a strange condition of things.
No shore was visible on either side, and overhead was empty space instead of the low lying roof that always met their gaze.
"We are no longer moving," cried the colonel in astonishment.
"Impossible!" exclaimed Guy, but on putting his hand in the water all doubt was instantly removed. The canoe was stationary.
They paddled on to the right, to the left, in every direction, but the dark water lay calm and sluggish on all sides.
"We are on a lake," said Guy. "There is no doubt of it; a vast underground lake."