“Never see a bull I couldn’t handle,” he said as the men, having returned, scrambled into the car.

“Do you know who it belongs to?” asked Jack, as he turned round and headed back to where they left the luckless professor.

“I reckon it’s that big Holstein of Josh Crabtree’s.  He’s pretty near as mean as his owner, and that’s considerable.”

Jack thought of the hole in the wall and hoped they would reach there before farmer Crabtree, and so avoid serious complications.

He drove at top speed, while the friendly farmer and his workmen clung to the sides of the car and looked rather scared at the rate they were going.

“There’s the tree,” exclaimed Jack, as they came in sight of it, “and there’s the gap in the fence.”

“And where’s the bull?” asked Tom.

“And where’s the professor?” added Dick.

Not a trace of the man of science or of the ferocious animal was to be seen.

“Are you sure you boys didn’t dream all this?” asked the red-faced farmer suspiciously.

“There ain’t even a cow in sight in the pasture lot,” said one of the men.

“I reckon this is some sort of a fool joke,” added another.

“It isn’t.  Indeed, it isn’t,” protested Jack.

“The professor is some place around,” said Tom.

But a lengthy search of the vicinity failed to show anything except that the professor had vanished as if the earth had swallowed him.

CHAPTER IV.

“Where is he?”

“Professor!” hailed Dick, at the top of his lungs.

“Professor!” bawled the farm hands.

The red-faced farmer himself regarded the boys quizzically.

“What sort of a chap is this professor of yours?” he asked with an odd intonation.

“He’s a geologist,” replied Dick.  “Why?”

“Oh, I thought he might be a conjurer,” was the rejoinder.  “He seems to be pretty good at hiding himself.”

“Hark!” exclaimed Jack suddenly, standing at pause and listening intently.

“What’s up?” demanded Dick, instantly on the alert, too.

“I heard something.  It sounded like——­”

“There it is again,” cried Tom.

A faint, far-off cry, impossible to locate, was borne to their ears.

“It’s a call for help,” declared Dick.

“That’s what it is,” agreed the red-faced farmer.  “Must be that perfusser of yours, but where in the name of Sam Hill is he?”

It was a puzzling question.  The faint cries appeared to be muffled in some way.  They looked about them, endeavoring to locate their source.  Suddenly one of the farm hands spoke.

“I used to work fer old Crabtree,” he said.  “There’s an old well hereabouts somewheres and maybe he’s fell down that.”

“Where is it?” demanded Jack.

“Back in the meadow yonder,” said the man, pointing in the direction of the pasture lot.