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.