GATHERING CLOUDS.

Much to the relief of Matt, McGlory and Lorry, the Chinese boy had not encountered intruders. His trouble was of quite another sort.

In order to watch all sides of the boathouse, he had been tramping around three of its walls, from the waterfront on one side to the waterfront on the other. The day was hot and the exertion tiring. Ping, after some reflection, conceived the brilliant idea of climbing to the roof and watching from the ridgepole.

An elevated position of that kind would enable him to rest and keep eyes on the vicinity in every direction.

Some empty boxes, piled one on the other, lifted him high enough to reach the eaves. Kicking off his sandals, he took the slope of the roof in his stocking feet and was soon by the flagstaff that arose from one end of the peak on the waterside of the building.

A timber, equipped with rope and tackle, projected outward from the peak. For no particular reason, other than to test his agility, Ping lowered himself astride the projecting timber and hitched outward to the end.

Here a sudden gust of wind struck him. Lifting both hands to save his hat, he lost his balance and rolled sidewise off the timber. But he did not fall. His trousers caught in the stout iron hook by which the pulley was suspended; and, when Matt, McGlory and Lorry finally located him, he was sprawling in midair, badly scared, but as yet unhurt.

"Motol Matt," howled the youngster, "savee Ping! No lettee fall! Woosh!"

"Sufferin' heathens!" gasped McGlory. "How in the name of Bob did the Chink ever get in that fix?"

That was no time to guess about the cause. If Ping's clothing was to give way he would suffer a bad fall on the planks of the boathouse pier. Pulling the tackle rope from the cleat to which it was fastened, Matt climbed hand over hand to the projecting timber.

"Catch hold of my shoulders, Ping," he ordered.

Ping's arms went around him in a life-and-death grip. Then, supporting himself with one hand, Matt detached the Chinaman from the hook with the other and both slid to the pier in safety.

"You gave us a scare, Ping," said Matt. "We didn't know but you had found some one sneaking around the boathouse. How did you get in that fix?"

Ping explained, and the boys had a good laugh. Shortly afterward Lorry dragged his motor cycle to the top of the bank and chugged away home.

It was about two o'clock when Newt Higgins, the young machinist, arrived with the new motor. His father had brought him across. The engine was unloaded by means of the block and tackle and carried inside.

While Higgins was taking the old motor out of the Sprite, Matt connected up the new one with gasoline tank and battery and got it to going. It ran perfectly.

From that time on there were several days of feverish activity in the boathouse. The hull of the Sprite had to be strengthened. The original motor had been installed on short bearers, which, according to Matt's view, was entirely wrong. The motor bed, he held, must be rigid and the vibration distributed over as great an area as possible.

A heavy bed was put down, and on this two girders were laid, shaped up to take the rake of the motor and tapering off at the ends. These girders extended as far forward and aft as the curve of the hull would allow.

Lining up the shaft was an operation which Matt attended to himself. This job gave some trouble, but was finally finished to his satisfaction.

The new engine was set farther aft than the old one had been. This enabled Matt to bring the gasoline tanks farther aft, as well. The hood had to be made longer, and a stout bulkhead was built between the engine space and the cockpit.

All controls were to be on the bulkhead. The electric outfit was placed close to the motor, where it would be protected from wet and dampness by the hood. In addition to this, the eight cells of the battery were inclosed in a box and filled around with paraffine.

The hull had already been covered with canvas, given two coats of lead and oil and rubbed down. The last thing would be a coat of spar varnish.

Saturday night Matt dismissed the machinist.

"I wish I knew as much about motors as you do," the machinist had said as he pocketed his pay. "You're Class A, Motor Matt, and you've given Lorry a boat that'll win. I'm goin' to see that race. The Yahara boys are on our lake, you know, and this part o' town is with 'em to a man. It's surprisin' how this section of town is set on havin' the Yahara club get back the cup."

"We're going to do our best, Newt," Matt had answered, "and you'll see a pretty race, no matter how it comes out."

"You bet you!" averred Newt. "Good-by and good luck, Matt. I'd be tickled if we could work together all the time."

During the work McGlory had made himself generally useful. He could run the small launch which Lorry had brought to the boathouse for Matt's use, and whenever there were any errands across the lake not requiring Matt's attention at the machine shop McGlory attended to them.

Ping proved to be a good cook, and prepared the meals on a gasoline stove. When he was not busy in the culinary department he was guarding the boathouse against prowlers.

The boathouse was nicely situated for the work Matt and his friends were doing. There were no other boathouses for half a mile or more on either side of it, and the steep banks by which it was surrounded on every side but toward the water gave it an isolation which had commended it to Matt and Lorry.

It had not been used for some time when Lorry had leased it from the owner, but was in a very good state of repair for all that.

It contained a well which opened directly into a protected cove. An incline fitted with rollers made it easy to launch a boat or to haul it out upon the floor. The water door came down to the lake level, and both door and well were wide enough to admit a craft of eight-feet beam.

During all these days of work Ping had not detected a single person skulking around in the boathouse's vicinity. Matt worked until late every night, and there was always some one on guard on the outside from sunset till sunrise. Generally it was McGlory, but occasionally Lorry would come over and insist that the cowboy should sleep while he did the sentry duty.

It was nine o'clock Saturday night when Matt finished with the varnish coat and, dropping his brush, stood back to look at the trim, shadowy lines of the boat.

"She's a beauty, Matt, and no mistake," called some one from the door.

"Hello, George!" answered Matt, turning to place the lamp on the workbench and scrubbing his hands with a bunch of waste. "She'll do, I think. Anyhow, the Dart won't run any rings around us."

"You must be about fagged," said Lorry as Matt dropped down on his cot by the wall. "You've worked like a galley slave, and if we win the prize it will be all owing to you."

"I'm tired, and that's a fact," Matt answered, "but I've got some good feelings in me, as my old Dutch pard used to say. If a fellow's mind is easy it doesn't matter so much about his body."

"I came over to see if you'd heard anything from our friends the enemy yet," said Lorry.

"They haven't peeped," Matt laughed. "I guess they've decided to let us alone."

"Don't you think that for a minute," returned Lorry earnestly. "Merton and his pals have been lying low, but the clouds have been gathering. The storm will break before Tuesday, and I'm wondering and worrying as to how it is going to hit us."

"We'll weather it," said Matt lightly, "no matter what shape it takes. It's a cinch that Merton hasn't been able to find out a thing about what we've been doing. That roll of drawings is all he has to base an opinion on, and the Sprite is as different from those plans as you can well imagine. We've fooled Merton to the queen's taste."

"And probably he thinks he has fooled us," smiled Lorry.

"Have you been able to discover anything about the Dart?"

"Not a thing. The Winnequas are guarding her as though she was a lump of gold. But there are hair-raising tales, all over town, of the tremendous speed a new boat on Third Lake is showing."

"The Wyandotte hasn't been kicking up the water around the point for a couple of days now."

"I guess Merton thinks we're so busy here we won't pay any attention to her. Ever since he stopped sending the Wyandotte to Fourth Lake he has been speeding the Dart in the evening on Third."

"Well, Merton's consistent, anyhow, no matter what else you can say about him."

"I've got orders from dad and sis to take you over to Yankee Hill to spend to-night and Sunday," said Lorry, after a slight pause. "Will you go?"

"Sorry, old chap, but I can't," Matt answered regretfully. "I'm going to be Johnny-on-the-spot right here in this boathouse till the Sprite leaves to enter the race. I'm not taking any chances with her."

"But can't McGlory and Ping look after the boat?"

"They can, yes, and there isn't anybody I'd trust quicker than I would McGlory; but, if anything should happen to the Sprite between now and Tuesday, I want to be the one who's to blame."

"I guess I know how you stack up," observed Lorry, with a touch of genuine feeling. "You're doing a whole lot for me, Matt, and my folks know it and appreciate it just as much as I do. I hope I can pay you back some time."

"Nonsense, George!" deprecated Matt. "Do you think there isn't any fun in this thing for me? I've enjoyed myself every minute I've been tinkering with the Sprite, and the best part of it all will come when I show the Dart the way across the finish line next Tuesday."

Half an hour later Lorry got into his hired launch and started for home. All was quiet and peaceable in the boathouse, but, even then, a storm of trouble was preparing to break—a storm that was to try the three friends to the uttermost and to come within a hair's breadth of ruining their prospects in the power-boat contest.