Allan was silent.

But when hours passed away and there were no signs of their returning, when gloaming itself began to fall around them, and the stars at the crater’s mouth assumed a brighter hue, Allan’s anxiety knew no bounds, and he proposed to De Vere to go in search of his friends.

“Ah! if dat vere indeed possible!” was the reply.

“And why not?” said Allan.

“For many reasons: de balloon vill even now hardly bear de strain on her anchors; de loss of even your veight vould require such delicate manipulation on my part, dat I fear I could not successfully vork in such small space. Alas! ve must vait. But there yet is hope.”

Meanwhile it behoves us to follow Ralph and Rory. They had faithfully promised De Vere they would go but a short distance from the car, and that promise they had meant to redeem. They found that the ground sloped downwards from the mouth of the crater, but there was no want of light, as yet at least, and thus not the slightest danger of being unable to find their way back, for were there not their footsteps in the snow to guide them? So onward they strolled, cheerfully enough, arm-in-arm, like brothers, and that was precisely how they felt towards each other.

The road—if I may say “road” where there was no road—was rough enough in all conscience, and at times it was difficult for them to prevent stumbling over a boulder.

“I wonder,” said Rory, “how long these boulders have lain here, and I wonder what is beneath us principally, and what those vast stalactite pillars are formed of.”

“‘Bide a wee,’ as the doctor says,” replied Ralph; “don’t hurry me with too many questions, and don’t forget that though I am ever so much bigger and stronger than you, I don’t think I am half so wise. But the boulders may have lain here for ages: those ghostly-looking pillars are doubtless ice-clad rocks, partly formed through the agency of fire, partly by water. I think we stand principally on rocks and on ice, with, far, far down beneath us, fire.”

“Dear, dear!” said Rory, talking very seriously, and with the perfect English he always used when speaking earnestly; “what a strange, mysterious place we are in! Do you know, Ralph, I am half afraid to go much farther.”