"Told what?" asked the senator's son.

"About Nat Poole. I got the word from a friend of mine, Joe Devine. Joe was talking with Nat Poole, and he said Nat was very angry at all of us, and angry because Mrs. Wadsworth was giving us the party, especially as he wasn't invited. Joe said Nat intimated that he was going to make the affair turn out a fizzle."

"A fizzle?" queried Phil. "How?"

"Joe didn't know, but he told me, on the quiet, that I ought to watch out, and ought to warn the others. But I don't like to say anything to Mrs. Wadsworth, or the girls. You see, it may be only talk, and if it is, what's the use of getting the ladies excited?"

"It would be just like Nat to play some dirty trick," said the shipowner's son. "The question is, What will it be?"

"Somebody ought to stand guard," was Roger's advice. "And I think we ought to tell Dave."

This was readily agreed upon, and Dave was told a few minutes later. His face at once showed his concern.

"It mustn't be allowed!" he said, earnestly. "I don't care so much on my own account, but think of Mrs. Wadsworth and the girls! Yes, we must keep our eyes open, and if anything goes wrong----" He finished with a grave shake of his head.

"What are you boys plotting about?" asked Laura, as she came up. "Come, it won't do to stick together like this, with all the girls arriving.

Dave, go and make folks at home,--and you do likewise," she added, with a smile at Phil and Roger.

The boys dispersed and mingled with the arriving guests. Dave did all he could to make everybody feel at home, but all the while he was doing it he kept his eyes wide open.

Presently, chancing to look in the direction of the automobile house, Dave saw somebody skulking along a hedge. The person was visible only a second, so the youth could not make out who it was.

"Maybe it's all right, but I'll take a look and make sure," he told himself, and excused himself to a girl to whom he had been talking. As he hurried across the lawn he pa.s.sed Phil.

"Come with me, will you?" he said, in a low voice.

"See anything?" demanded the shipowner's son.

"I saw somebody, but I am not sure who it was."

Taking care not to make his departure noticeable, Dave walked toward the automobile house and Phil followed him. Soon the pair were behind some rose bushes and then they gained the shelter of the heavy hedge.

"There he is!" said Dave, in a low voice. "It's Nat Poole, sure enough!"

"What's he doing?" asked Phil.

"Nothing just now. But I guess he is up to something."

Keeping well out of sight behind the hedge, the two boys watched the son of the money-lender. Nat was sneaking past the automobile house and making for a washing-shed adjoining the kitchen of the mansion.

"I think I know what he is up to," murmured Dave. "Come on after him, Phil."

As silently as shadows Dave and Phil followed the money-lender's son to the shed. Once Nat looked around to see if the coast was clear, and the followers promptly dropped down behind a lilac bush. Rea.s.sured, Nat entered the shed, and Dave and Phil tiptoed their way up and got behind the open door.

The hired help were in the kitchen, so the shed was empty. On the floor stood an ice-cream freezer full of home-made ice-cream, and on a shelf rested several freshly baked cakes, all covered with chocolate icing, set out to harden.

"Now I'll fix things," Dave and Phil heard the money-lender's son mutter. "Salt in the cream and salt in the layer cakes will do the trick! Some of the boys and girls will think they are poisoned!"

Nat took up a bag of salt that was handy,--used for making the cream,--and proceeded to open the can in the freezer. Dave watched him as a cat does a mouse.

Just as Nat was on the point of dumping some of the salt into the ice-cream he felt himself jerked backwards. The salt dropped to the floor, and Nat found himself confronting Dave, with Phil but a few steps away.

"You contemptible rascal!" cried Dave, his eyes flashing.

"Why--I--er----" stammered the money-lender's son. He did not know what to say.

"Going to spoil the cream, eh?" came from Phil. "It was a mighty dirty trick, Nat."

"On a level with what you did to Professor Potts," added Dave.

"I--er--I wasn't going to do nothing!" cried Nat, with little regard for grammar. "I--er--I was looking at the ice-cream, that's all."

"A poor excuse is worse than none," answered Dave, grimly. "You were going to put salt in the cream and spoil it, you needn't deny it."

"See here, Dave Porter, I want you to understand----"

"Don't talk, Nat, we know all about it," broke in Phil. "You planned to come here yesterday, and we can prove it. We were on the lookout for you."

At this a.s.sertion the face of the money-lender's son changed. He grew quite pale.

"I haven't time to waste on you--I want to enjoy this party," said Dave.

"Come along with me."

"Where to?" demanded Nat.

"I'll show you," answered Dave, and caught the money-lender's son by the arm. "Catch hold of him, Phil, and don't let him escape."

CHAPTER V

AT NIAGARA FALLS

"See here, I want you to let me alone!" stormed Nat Poole, and he tried to jerk himself free.

"Listen, Nat," said Dave, sternly. "If you make a noise it will be the worse for you, for it will bring the others here, and then we'll tell about what you tried to do. Maybe Mrs. Wadsworth will call an officer, and anyway all the girls and the boys will be down on you. Now, if you want Phil and me to keep this a secret, you've got to come along with us."

"Where to?" grumbled Nat, doggedly.

"You'll soon see," returned Dave, briefly, and with a wink at his chum.

Somewhat against his will, Nat walked toward the end of the garden. He wished to escape from Mrs. Wadsworth and the others, but he was afraid Dave and Phil contemplated doing something disagreeable to him. Maybe they would give him a sound thrashing.

"Don't you touch me--don't you dare!" he cried, when the barn was readied. "Remember, my father can have you locked up, Dave Porter!"

"Well, don't forget what Professor Potts can do to you, Nat," answered Dave.