"Now, I'll show the folks a few things," Hi resolved, putting on the best spurts of speed that were in him. It was truly a fine performance for a Grammar School boy.

Yet, to the amazement of most of the onlookers, d.i.c.k also was doing some very speedy swimming now. A yard he gained on Martin, then another and another. When they were still fifty yards from the stakeboat d.i.c.k suddenly changed his stroke and surged ahead, distinctly in the lead.

"Confound the human steam launch!" gasped Hi, almost choking, as he saw the powerful strokes of the swimmer ahead. "He'll make me look like a fool if I don't haul up on him---and the distance left is so confoundedly short!"

Now it could be seen that Martin was exerting every ounce of energy and strength that he possessed. Yet still young Prescott gained.

Then Martin foolishly lost his head altogether.

"If I can't win I'll make it look like a fluke!" he gritted.

Just as d.i.c.k was nearing the stakeboat, Hi threw up one hand.

"I've got a cramp!" he shouted. "Help!"

To some on sh.o.r.e he appeared about to sink. d.i.c.k pa.s.sed the stakeboat, then turned like a flash and swam back toward Hi.

"Prescott wins!" called Len Spencer.

A few more strokes brought d.i.c.k up to where Hi pretended to flounder.

"Keep quiet, Hi, and let me get a hold on you," d.i.c.k offered.

"I'll have you at the pier in a jiffy."

"You get away from me," snarled Martin. "I don't want any of your kind of help."

With that Hi appeared to forget his recent complaint of "cramp,"

for he made a l.u.s.ty plunge toward the pier and pulled himself up.

Then, an instant later, he must have remembered, for he a.s.sumed an expression of pain and limped.

"There's that mean cramp again," he muttered. "I'd have won by a good many yards if it hadn't been for that."

Some of the Central Grammar boys nearby were impolite enough to laugh incredulously.

"Oh, I've dropped my handbag into the river!" exclaimed one woman to another suddenly, at the end of the pier.

The other woman turned, giving a quick, startled glance toward the water.

"I---I don't know how it happened," gasped the loser. "There it is, away down the stream, floating toward that boathouse.

Oh, Master Prescott, do you feel able to go and get it for me?"

"I'll do it with pleasure, madam," d.i.c.k nodded. He looked for a moment. Then, seeing a black floating object, he started after it, his stroke apparently none the weaker after his swift race.

It had floated nearly under the boathouse at the water end. The building in question belonged to the estate next to that from which the swimming contests had been conducted. This boathouse was closed, for the owners had not yet come to Gridley for the summer. The windows of the little green building were shuttered from the inside. Over the water the walls came down to within six inches of the present level of water.

Keeping his eyes turned toward the black, floating object, d.i.c.k swam easily to the spot. The black object floated under the open sidewall into the boathouse. Just as d.i.c.k got there he dived, duck fashion, head first, and pa.s.sed to the interior of the boathouse at the river end.

As he came up inside d.i.c.k's first discovery was that of artificial light in the boathouse. Then his gaze rested on the platform end over the land.

"Amos Garwood here, of all places!" gasped the astonished Grammar School boy.

Chapter XXIV

CONCLUSION

The mentally queer inventor had rigged up a bench just under shelves on which rested tools and boat supplies.

Just at the moment the inventor had his back turned to the water as he stood working at his bench. d.i.c.k was able to look at him while not in immediate danger of being seen himself.

How quietly the Grammar School boy trod water! He hardly dared breathe, for fear of giving an alarm.

Yet, even in all his astonishment, Prescott did not forget to let one hand close over the handle of the black bag whose recovery had brought him here.

"I can't do anything with Garwood alone," reflected d.i.c.k swiftly.

"I must get out, if I can, without making a noise, and then give the hurry alarm. That fellow is mixing something, and, if he isn't stopped soon, he's quite likely to blow up the boathouse, himself included."

Fortunately there was sufficient depth of water at this outer end of the boathouse. Prescott let himself sink so quietly that there was barely a ripple above his head. Next, with a few cautious strokes, he carried himself past the hanging side wall and into the open upstream.

"Gracious, but no wonder Garwood has been able to keep away from pursuers," thought the boy excitedly, as he swam steadily up toward the other pier. "He has a place where not even a Sherlock Holmes would ever think of looking for him. Why, he could work, sleep and eat there and never give a sign of his presence!"

"Did you get it?" called the owner of the handbag eagerly.

"Yes, ma'am," d.i.c.k replied.

"The bag wasn't open, was it?"

"No, ma'am."

"Let me have it quickly, please. Oh, I'm so thankful! Here is my purse with all the money safe and sound. Wait, Master Prescott, I must reward you suitably."

"No; I thank you," d.i.c.k replied, his color rising. "Your thanks are enough. I've been taught that courtesy can't be repaid with cash. You are very, very welcome to any service that I was able to do you."

As d.i.c.k hurried into the Central Grammar "dressing room" he found all five of his chums waiting to rub him down and help him dress.

"Here, give me that towel, and get out on other business in a hurry!" begged d.i.c.k. "Dave! Tom! Amos Garwood is in the boathouse below here, working at a bench. Get some of the men and rush down there to make a capture. Greg, run and see to it that a launch moves down to the river end of the boathouse in case Garwood tries to get out that way when he hears the alarm!"

Prescott's chums darted out in a hurry. d.i.c.k half dried himself in a few frenzied dabs with the towel. Then he pulled on his clothing faster than ever before.

He got outside on the pier just in time to see Dave and Tom leading a dozen men stealthily toward the door of the boathouse. Out on the water Len Spencer's launch, with half a dozen men in it, stood as river sentinel.

While those approaching the boathouse door were still more than a score of feet away there came a startling interruption.

Bang! sounded inside. The door of the building strained an instant, but did not give way.