Bad indeed was the case when Silas gave up hope.

“Say, Mervyn,” he continued, after a pause of a few moments, “you call this location the North Pole? I reckon if I had the naming of it, it ’uld be the ‘Gate of Hell,’ spelt large. Of all the God-forsaken parts I ever struck, this romps in an easy first. The Yellowstone Badlands are a paradise to this yer settlement!”

Hereafter a gloomy silence settled upon the party, broken at length by the appearance of Wilson.

“The thing’s beyond me!” he exclaimed; “not a rod is out of place, not a screw is missing, yet never a stroke can I get out of them for all my trying.”

In a few terse sentences Garth explained to the engineer the cause of the breaking down of the machinery.

“Great Scott!” cried Wilson, “you don’t mean——?”

He broke off short, as a rumbling explosion burst from the crater.

The eruption had recommenced!

Moving to the window, Wilson peered out through the steam-covered glass. As he did so a great shaft of flame shot upward from the water alongside, scorching the paint on the vessel’s hull.

With a startled exclamation the engineer shrank back from the window.