“I think I’ll take a hand in this myself,” smiled the Professor.  He ran to his tent, returning quickly.  In his hands he carried two pails of water.

Unluckily for the boys, they had failed to observe what he was doing.  Nor did they understand that they were in danger until the contents of the two pails had been dashed over them.

There were yells in earnest this time.  The water turned the dirt into mud at once, and their faces were “sights.”  Stacy’s face had been protected, in a measure, by the other boys who were bending over him rubbing in the sand.

The unexpected bath put a sudden end to their sport, and they staggered out shouting for vengeance.  They did not even know who had been the cause of their undoing.

The Professor, as he walked away smiling, had handed the pails to the grinning Juan with instructions to refill them.

The unfortunate Juan, bearing the pails away, was the first person to catch the eyes of the lads, as they rubbed the sticky mud out of them.

With a howl they projected themselves upon him.  Juan’s grin changed instantly to an expression of great concern.  He went down under their charge, with four boys, instead of three, on top of him.

“Duck him!” shouted some one.

“Yes!  Douse him in the spring!” chorused the boys.

Juan cried out for the Professor, but his appeals were in vain.

Shouting in high glee the lads bore him to the spring from which they got their water.  They plumped him in, not any too gently, again and again.

“Now roll him in the sand,” suggested Ned.

They did so.

The wet clothing and body made the sand stick to him until the lazy
Mexican was scarcely recognizable.

At this point Professor Zepplin took a hand.  He came bounding to the scene and began throwing the boys roughly from their unhappy victim.  Perhaps be was not greatly disturbed over the shaking up the guide had sustained, but of course he confided nothing of this to the boys.

“You ought to be ashamed of yourselves—­ for four of you to pitch on to one weak Mexican!  I’m surprised, young gentlemen.”

“But—­ but—­ he ducked us,” protested Ned.

“He did nothing of the sort.”

“What—­ didn’t duck us?  Guess I know water when I feel it,” objected Walter.

“You were ducked, all right, but it is I, not Juan, who am responsible for that.”

“You?” questioned the lads all at once.

The Professor nodded, a broad grin on his face.

“But he had the pails.”

“I gave them to him, after pouring the water over you.  That’s what is known as circumstantial evidence, young gentlemen.  Let it be a lesson to you to be careful how you convict anyone on that kind of evidence.”

“Fellows,” glowed Chunky, “we’ve made a mistake.  Let’s make it right by ducking the Professor.”

The boys looked over Professor Zepplin critically.