“We have some faint idea of what the storm was,” put in Nat; “but can you explain something to us?” and he described to the professor the manner in which the Nomad had been drawn toward the volcanic islands.

“Pure magnetism,” declared the scientist, “a common feature of such storms.”

“But our craft is of wood,” declared Nat.

“Yes, but your engines, being metallic, of course, overcame that resistance. You are fortunate, indeed, not to have been drawn down when the islands vanished. It was a terrific sight.”

Nat explained that during that period they were all unconscious and then went on to tell of the experiences through which they had passed.

“Oh, why wasn’t I on board your craft?” moaned Mr. Tubbs, as he concluded. “What a picture that chasm would have made! It’s the opportunity of a lifetime gone.”

The boys could hardly keep from smiling over his enthusiasm; but Nat struck in with:

“It’s an opportunity I don’t want to encounter again,” an opinion with which everybody but Mr. Tubbs—even the professor—concurred.

“And now,” said the man of science suddenly, “I don’t wish to alarm you, young men, but it is possible that there may be some reflex action exerted by this storm. In other words, there may be a mild recurrence of it. In my opinion we had better get as far away from this spot as possible.”

The others agreed with him. Ding-dong dived below to his engines. Nat took his station on the bridge.