Not since the days preceding the Firemen's Tournament when the motorcycle fire department was being outfitted had the scout engineers been busier than they were the following few weeks. Every afternoon after the academy let out, and every evening they could spare from their studies was devoted to the construction of the moth trap. They worked with snap and vim, for upon the success of their product depended the possibility of a troop motorboat.

And it was well that they had this enthusiasm, for a time limit had been set on the contest. According to the information received from the Mayor's office the contest would close the last Monday in June and the five days following would be devoted to testing the various methods and appliances entered. With the assistance of Mr. Ford the lads had already made their entry, sending drawings and details of their device to the committee of judges. But in spite of their fast work It was apparent that they would not complete their contrivance until the middle or latter part of the week set for the test.

They were determined that $100 of the $200 offered by the town should be added to the troop's account in the Woodbridge bank, however, and when scouts take that attitude in any matter one can rest assured of a period of industry. They worked like beavers and the rap, rap, rap of hammers, the buzz-z-z of band and jigsaws and the hum-m of motors could be heard in their workshop on the first floor of the headquarters building at almost any hour.

Of course, the boys were not entirely sure that they would win first or even third prize, because there were any number of others competing for the same honors. Indeed, farmers and even business men in and around Woodbridge were experimenting with chemical exterminators and various other ingenious devices and all of these would have an equal chance with the appliance invented by the boys. But the lads were sportsmen enough to take their chances with the rest. Indeed, they even went so far as to stake some of the precious motor money on the result, for they took fifteen dollars from the Woodbridge bank to pay for the lumber and other material needed to build Nipper's big vacuum pest catcher.

"If we don't win that prize now all our chances for a motorboat are gone for sure," said Babe Wilson when Bud Weir announced the withdrawal of part of the fund.

"Well, that isn't the way to look at it. Just say we are going to win the prize and then get busy and work for it," insisted Bud, trying to instil confidence in the stout scout.

Day by day the neatly finished boards grew to represent Nipper's idea of a moth exterminator. And finally, after what seemed to the boys an unusually long time, the suction fan arrived from Bruce's father's mill. It was already attached to a one-quarter horsepower electric motor, for Mr. Clifford knew that none of the motors in the scouts' workshop were small enough to be used on a fan with six-inch blades. By this time the lads had all but finished the big wooden trumpet and it was only necessary to set the fan, bolt the motor into place and give the whole thing a coat of paint.

But already the last Monday of the month had passed and only a day or two remained in which the boys could test their machine before the judges. Day and night since the beginning of the week contestants had been claiming the attention of the judges with their schemes for extermination. Most of these had been tried out and many were said to be very successful. On one or two occasions the scouts had gone out to look over these tests, but to their mind none of them looked as effective as the moth trap they were building.

On Thursday night Mr. Ford visited headquarters looking rather anxious, for he had heard very little from the boys during the last few days and he was afraid they were not going to put their machine together in time to appear before the judging committee with it. He was greatly relieved to find that the lads were about to put the motor and fan in place and he realized that this marked almost the last stage of their work.

"Well, boys, it looks all right to me," he said.
"When are you going to be ready for the official tryout?"

"Just as soon as we can put the automobile lamp into place. We are building some iron brackets for that now. We'll be all ready by tomorrow evening, I guess. That will give us one full day leeway. The tests can be conducted up to midnight Saturday, can't they?"

"Sure, I'll see that the judges are ready for you. I have an engagement that may keep me a little bit late, but I'll get there. Where are you going to test it?"

"Out on the back road here; down by the bend opposite Chipman's Hill," said Nipper.

"Fine, I'll be there. Say, by the way, I was talking about your idea down town this evening and a reporter from the Journal heard me. He seemed very much interested when I told him about your work and he wants to come up and see the machine. He'll probably be up some time to-morrow. Perhaps I can get him up to see the test. If I can I—Listen, is that some one coming? Sure enough, perhaps it is he. Open the door, Bruce."

Bruce swung open the big double door and Rogan, one of the reporters for the Woodbridge Journal and the local correspondent for the St. Cloud Call, entered.

"Hello, boys," he shouted good naturedly. "Heard you have a new wrinkle in moth catchers. Is that the machine? Looks mighty businesslike. Is it ready to test? Well, if there isn't Mr. Ford. How are you? What do you think of the scout's invention? How does it work? Whose idea is it. Where—?"

"Oh, goodness gracious, don't ask 'em so fast," said Bruce. "We'll answer them one at a time and explain the machine to you if you'll give us a chance."

"Sure. Excuse me. Go right ahead," said Hogan, his inquisitive blue eyes taking in everything in the room.

Nipper had the honor of describing his own invention, which he did with no little pride. And evidently Rogan was impressed for, after cross examining Mr. Ford and going into the device from every angle, he wrote a two-column story which appeared on the first page of the Journal the following morning. Also he telephoned a story to the St. Cloud paper which the boys read the following afternoon.

As soon as the Academy closed the next day the scouts hurried to headquarters, for they had a great deal to do before they could carry out the test that evening. Two or three attended to the work of removing one of the searchlights from "Old Nanc" and putting it into place on top of the moth catcher, while the rest of the boys strung a temporary line of wire from the headquarters' switchboard to a point about two hundred yards up the road. They intended to conduct the test there and throw the searchlight into the trees on Chipman Hill across the valley.

It was dinner time when the wires were in place and the scouts, after a last look about, all went home to get something to eat and to wait the coming of darkness.

They began to return to headquarters about half past seven. Bruce, Nipper Knapp, and Ray Martin were the first to arrive and, to their surprise, they found at least two dozen people waiting outside of headquarters.

"Well, what does this meant" inquired Bruce of Nipper.

"Well, I guess they read Rogan's story in the Journal. He said we were going to have a test to-night, you know."

"Then we're going to have a gallery of spectators! Oh, well, we don't mind, do we, boys?"

"You bet we don't—if the thing will only work," said Nipper.

Soon, other scouts arrived and presently an automobile rolled up to the door and four of the town's councilmen climbed out. The party was composed of Mr. Bassett, Mr. Bates, Mr. Adams and Mr. Franklin, all members of the Mayor's committee of judges. The lads were disappointed not to see Mr. Ford among them, but they felt confident that he would appear in time for the official test.

The Councilmen looked over the moth trap with critical eyes and asked innumerable questions. Then finally Mr. Bassett, chairman of the committee, spoke.

"Well, Scouts, it surely looks like a good plan, but will it catch 'em, that's what we want to know?"

"We are not certain of that ourselves, sir, but we'll take it out and test it. Then we'll surely know," said Nipper. In a few moments the moth catcher had been loaded into "Old Nanc" and the scouts, judges and about one hundred townfolk who had gathered to see the demonstration, started up Otter Creek road. By the time the boys had loaded the moth catcher into "Old Nanc" the entire troop was there.

Twilight had gone and the stars were coming out when "Old Nanc" arrived at the appointed location. Every one was extremely curious and the moment the moth catcher was put on the ground men and women alike began to inspect the contrivance closely. It was fully twenty minutes before the boys could connect the wires to the searchlight and the motor. Then a scout was sent post haste back to headquarters to throw the switch and let the current into the new line.

When this was done Nipper, who was in charge on this occasion, took his place beside the contrivance. Scouts with staffs were detailed to keep the small crowd back and away from the front of the machine.

"Are you all ready, Nipper?" said Bruce.

"Sure," said Nipper. Then, "say, is Mr. Ford here? I wish he was; I'd like to have him see this. Oh, Bruce, if it will only work! I'm getting as nervous as a cat." He glanced toward the automobile where the four judges sat waiting.

"Tut, tut, don't get fussed," said Bruce, trying hard to conceal his own suppressed excitement.

"All right, here goes," said Nipper as he turned the lamp switch, and a moment later the motor switch.

Instantly a long arm of light reached out across the valley and focused on the heavy growth of elm trees on the opposite hill side. The motor began to hum and the fan to buzz loudly. Every one was attention. Every eye was riveted in the long shaft of light that stretched forth into the night. A minute they waited, two minutes, five minutes! Nothing happened!

"Oh—this suspense is terrible," groaned Nipper.

"You're right, it is," whispered Bruce.

Every scout felt the same way. Was it a failure? Was their idea only visionary, alter all? Oh, why didn't something happen to relieve the tension. Why didn't—

"Look! There's a moth," said some one.

"Where?" asked half a dozen breathlessly.

"Out there! Look! Can't you see him?" said others.

Sure enough, coming down the long pathway of light was a solitary moth winging its fitful way toward the lamp. Now it was in the light and now it dodged out into the darkness. But always it returned a few feet nearer to the waiting scouts. It seemed irresistibly drawn toward the auto lamp.

"Come on, come a little closer and we'll have you," whispered Nipper excitedly.

On it came toward the upturned mouth of the vacuum. It was ten feet away, then eight, seven, six. Now it felt the air disturbance, for it began to flutter harder. Then—zipp!

It was caught in the air current and in a twinkle disappeared down the yawning month of the sucker.

A mighty cheer went up. But they were silenced quickly when another moth appeared. But before this one had gone half way down the light shaft, two others came. Then came two more, then three or four, until they were fluttering in the white light like so many scraps of paper. And always when they reached a point over the opening of the sucker they were whisked out of sight like a flash, to be carried into the big bag at the other end of the machine.

The crowd began to press in closer. The men were talking loudly now and congratulating the young engineers, and as for Nipper and his comrades, well, they were pleased, and showed it by the smiles they wore.

But just at this moment the sound of an automobile coming from the direction of headquarters was heard and the next instant Mr. Ford's car dashed up.

"Hello, boys, how's she working?" he inquired and there was something in the tone of his voice that disturbed the scouts.

"Why, it's running in great shape. We have nearly half a bag full of moths now. What's the matter?" queried Nipper.

"Well, I have some bad news for you. I'm sorry, fellows, but your little machine isn't as original as we thought it was. Here's a telegram I received this evening from my attorneys in Washington. They say that a machine like yours was invented in Germany several years ago and patented in this country, too. They say several stories were printed about it in German and American magazines at the time. That means that we can't put it on the market as we had visions of doing and—!"

"Well, well, that's too bad," said deep-voiced Mr. Bassett, who had come out of the automobile with the other judges to hear what Mr. Ford had to say. "Too bad they can't get a patent on it. I thought the lads had an A-1 business proposition here and I was about to make 'em a spot cash offer for an interest in it. Why, it's the best thing we've seen in all the tests. No one has had anything anywhere near as good."

"But—but—you don't mean we can't win the contest," stammered Nipper nervously, looking at Mr. Bassett.

"Win! Win! Why, lads, you've won in a walk. Hasn't he, gentlemen? We haven't seen anything as good as this, have we?"

"We certainly have not," said Mr. Adams. "Of course, the boys win. They get the $100 prize, but that's a mighty small amount for such ingenuity. If it wasn't for that German inventor you could have made thousands of dollars out—"

"Pshaw, we only wanted first prize," exclaimed Nipper Knapp. Then he shouted, "Hi, fellows, we win, and we'll have our motorboat Whoope-e-e-e! Three cheers." And all, including the men, joined in: "Hip—hip—hoo-ray!" the noise of which didn't bother the moths in the least as they kept on fluttering toward the light and disappearing into the trap.