The three men stood listening and straining their ears in the direction from which the sounds had come, but there was a faint whispering as of running water down below, a trickling gurgle, and then startlingly loud came the nasal _quant_ of some night-heron at the water's side. This was answered twice at a distance, while again and again overhead there was the flutter and swish of wings, probably those of the oil-birds circling about the mouth of the cavern. "It's all over," said Briscoe at last, "and it's night-birds of some kind, I believe. Here, I've been listening so intently that I've forgotten my cigar. I'll go in and light it again with one of the bits of smouldering wood." He left his two companions, and they heard his footsteps as he went softly into the cavern to reach the fire. "Does it make you feel queer like, Mr Brace?" whispered Lynton. "Well, it sets me wondering, and makes me a little uncomfortable as to what the sound can be," replied Brace. "So it does me, sir. Always makes me feel queer if I don't understand what a noise is. I'm a bit of a coward, I'm afraid." "I've never seen any signs of it yet, Lynton," said Brace, laughing softly. "Oh, but I am, sir. That sound made me feel hot and then cold. I say, I've lost count about the points of the compass, but that's plain enough yonder across and up the river. That's the east, and the moon coming up." "That?" said Brace, as he gazed in the direction named. "Yes, I suppose so. It will be very beautiful when the moon rises over the mountain there and lights up the great canon. I feel disposed to wait till it shines on the river." "Moon!" said Briscoe, who had returned unheard, smoking vigorously, and looking in the darkness as if a firefly were gliding to their side. "We shan't see the moon to-night. It must have set a couple of hours ago." "Of course," said Brace, "and that can't be the east. I should say it's the west." "What, where that--I say, what light is that over there?" "Yes, what can it be?" said Brace, as he gazed at the soft glow. "It can't be a forest fire." "No: if it were we should see clouds of smoke between us and the stars, and they're clear right down to the top of the mountain. Why, Brace, there must be a volcano here, and that's the reflection from the glowing lava. I've seen something like that in the Sandwich Islands." "I'll go and tell my brother," said Brace. "No; perhaps he's asleep, and it would be awkward for him to get up here in the dark." "And you couldn't get him up in time," said Lynton. "Look: it's dying out fast. There: it's gone now." "Yes," said Brace, in a very low whisper. "How strange!" "Sort of afterglow," muttered Briscoe; "only it's a long time after the sunset. Well, gentlemen, I'm for bed. The scene is over and the lights are out. What do you say?"