“That’s what I call toeing a man out of trouble,” punned Dick, in the general relief that followed.

“Good thing it warn’t no further,” puffed Zeb, mopping his forehead.  “My arms feels as if they’d been stretched on one of them racks you read about in the history books.”

“How did it happen, professor?” asked Jack, as they scraped the mud off the scientist.

“It’s hard to say,” was the response.  “I was walking along, intent on my collecting, when I came to a barren patch of ground that was crusted over with stuff that looked like salt.  I stepped out on it to investigate and suddenly in I went.  Faugh! how it smells.”

“Yes, it isn’t exactly perfumed,” said Jack.  “But how did such a place come there?”

“It’s one of those mud-springs of hot water that are found in several places throughout the West,” said the scientist.  “It must have been quiescent for some time and then the thin skin of alkaline earth formed over it.  In Europe, or if we had that spring near a large city, it would be possible to make a fortune with it.”

“In what way?” asked Dick.

“As a curative bath,” replied the professor.  “Every year people spend fortunes to go to Europe and take just such baths.”

“Reckon I’d go without washin’ then,” commented Zeb.

“I’d just as soon bathe in rotten eggs,” said Dick.

“Well,” said Jack, “I guess we’ve got off about all the mud we can for the present.  We’d better be getting back.  It’s mighty fortunate that we came in time.”

“Yes, I was slipping into the stuff all the time,” said the professor.  “If I’d been alone on the island I might have never been seen again,” he added in quite a matter-of-fact tone.  “It’s too bad I lost that bag of fossils, though.  I had some fine specimens.”

“Goodness, no wonder you sank down!” exclaimed Jack.  “Why didn’t you let go of them?”

The scientist was mildly surprised.

“Why, how could I,” he asked, “until it became a question of life or death?  It’s too bad I had to lose them,” and he shook his head mournfully at the thought.

The journey was soon resumed, the Wondership rising buoyantly out of the dismal canyon.  They were not sorry to get back to the upper air for the gloom of the deep gulch had affected their spirits.  But so much time had been consumed in getting the professor out of his predicament that it was not long before twilight set in and they still had caught no glimpse of anything resembling the island they were in search of.

They decided to come to earth and make camp for the night and resume the search in the morning.  They made a hearty supper off the venison which remained, and turned in, without setting any watch, as there was no necessity for it out there with not a soul about for scores of miles.

It was about midnight when Jack was awakened by a wild yell from Tom.

“Ow!  Ouch!  Leggo my toe!” the younger of the Boy Inventors was shouting.