It was as light as day under those beautiful arches of ice, and truly a sight beautiful beyond description.
The ice assumed all sorts of fantastic shapes, and the roof of the mighty cavern seemed supported by huge pillars.
“This is like a trip to Fairyland!” cried Frank, rapturously.
But suddenly Barney clutched him by the arm.
The Celt’s face showed terror.
“Shure, sor, whativer is that?”
Frank felt a thrill of alarm.
A strange shock rang through the berg. This was followed by a distant terrible boom like thunder.
For a moment it seemed as if the berg was coming to pieces.
There seemed good cause for terror.