"Over at the machine shop, where I've been getting some work done," proceeded Matt, "they have a double-opposed, four-cycle automobile engine, capable of developing from eighteen to twenty horse-power at eighteen hundred revolutions per minute. The cylinders are five by five. That's a pretty stiff engine for the _Sprite_, but the hull could be strengthened, and we could put it in and get about ninety or ninety-five per cent. of the horse-power by gearing down three to one. After the gears wear a little, the percentage of horse-power might drop to eighty. This motor will drive a three-bladed propeller twenty-six inches diameter, thirty-two inches pitch. If the vibration don't shake me out of the boat at eighteen hundred revolutions per minute, the speed we'll get will be astonishing."
"Whoop!" exulted McGlory. "I don't know what it all means, but it listens good. I reckon there's a kick or two in the old _Sprite_ yet."
"You can't run a boat engine like you run an automobile motor, Matt," said Lorry.
"Of course not. A steady load and steady plugging in the water is a whole lot different from the give-and-take a motor gets in an auto; but we can keep up the eighteen hundred revolutions for ten minutes, anyhow--and the race only covers five miles. I'm fixing the _Sprite_ to win the race, that's all."
"By George!" exclaimed Lorry, "it takes you to make a fellow feel good, Matt! You know what you're doing, every time and all the time. Go ahead with the work, and bank on me to hold you up with both hands."
"What we're doing," said Matt, "we want to keep strictly to ourselves. Merton has our drawings, and probably thinks he knows just what we're about. Let him think so. If he springs a 'dark horse' on us, we'll get even by springing one on him."
"But can you get the _Sprite_ ready in time?" asked Lorry anxiously.
"Sure I can! I'll have to begin at once, though, and some of us will have to stay in this boathouse night and day to make sure that none of the Winnequas come prowling around. If you'll stay here with McGlory, George, I'll borrow your motor cycle to go over to the machine shop and dicker for that second-hand engine."
"Go on," said Lorry. "While you're there you might get a man to help you."