“No; it gives no metallic sound when you hit it.”

“Is it of ironwood?”

“No; it isn’t iron and it isn’t wood.”

“What is it then?”

“Impossible to say. But, anyhow, steel doesn’t touch it.” Uncle Prudent, in a sudden outburst of fury, began to rave and stamp on the sonorous planks, while his hands sought to strangle an imaginary Robur.

“Be calm, Prudent, be calm! You have a try.”

Uncle Prudent had a try, but the bowie-knife could do nothing against a wall which its best blades could not even scratch. The wall seemed to be made of crystal.

So it became evident that all flight was impracticable except through the door, and for a time they must resign themselves to their fate—not a very pleasant thing for the Yankee temperament, and very much to the disgust of these eminently practical men. But this conclusion was not arrived at without many objurgations and loud-sounding phrases hurled at this Robur—who, from what had been seen of him at the Weldon Institute, was not the sort of man to trouble himself much about them.

Suddenly Frycollin began to give unequivocal signs of being unwell. He began to writhe in a most lamentable fashion, either with cramp in his stomach or in his limbs; and Uncle Prudent, thinking it his duty to put an end to these gymnastics, cut the cords that bound him.

He had cause to be sorry for it. Immediately there was poured forth an interminable litany, in which the terrors of fear were mingled with the tortures of hunger. Frycollin was no worse in his brain than in his stomach, and it would have been difficult to decide to which organ the chief cause of the trouble should be assigned.