CHAPTER 15 THE DEMONSTRATION

Penny was due to meet Salt Sommers in ten minutes, but if she were late, she knew he would not leave without her.

Entering the crowded hotel, she waited her turn at the desk and then inquired if any Navy officers had registered.

“Not to my knowledge,” the clerk replied, consulting the register. “No, we’ve not had a Navy man in for at least a week.”

“Any Army officers?”

“The last was a sergeant who checked out two weeks ago. Most of our guests rent on a monthly basis. We have only a few rooms for transient guests.”

“Can you tell me if a Professor Bettenridge has called here in the last few days?”

“Not while I’ve been at the desk.”

The information convinced Penny she had not misjudged the professor. She now was satisfied he never had arranged with Navy officers to inspect his ray machine. Instead, he had misinformed Mr. Johnson, no doubt hoping to impress him that others were interested in the invention.

Quickly leaving the hotel, Penny hastened on to the news office. As she passed near the loading platform, Salt hailed her from a car parked there.

“Here I am,” he called.

Penny slid into the front seat beside him, apologizing for being late.

“That’s okay,” returned Salt, shifting into gear. “But we haven’t much time unless we hurry. You know the way, don’t you?”

“I do by daylight. And I think I can find the farmhouse, even if it should get dark before we reach there.”

Salt was a fast and very skillful driver. He chose the less frequented streets and soon they were in the open. They made excellent time, reaching their destination just as it began to grow dark.

“How shall we explain to the professor?” Penny inquired dubiously as the photographer parked the car under an oak tree along the highway. “He may think it strange that I returned.”

“Let him,” said Salt, unconcerned. “I’m here to get my camera.”

“Don’t go at him too hard,” Penny pleaded. “After all, there is a chance I was mistaken about the license number. In my excitement the night of the explosion, I may have remembered a wrong figure.”

“That’s so,” Salt acknowledged gloomily. “Well, we’ll see.”

“Why not pretend we’re here to get a feature story for the Star?” Penny suggested impulsively. “That way, I could ask him all the questions I like about the secret ray machine.”

“Any way you want to do it,” Salt agreed amiably.

He locked the car and they walked to the farmhouse. Learning that the professor and his wife were at the lake, they trudged down the lane.

“Wait!” Penny suddenly warned in a whisper.

Clutching Salt’s arm, she drew him into the shadow of a tree. At first he could not understand the need for caution. Then as Penny pointed, he saw a hunched figure with a lighted lantern, walking along the lake shore away from the cabin where Professor Bettenridge’s ray machine was kept.

“There goes Webb now!” Penny whispered. “He’s evidently going to the shack where the mines are stored.”

“What’s he carrying?” Salt inquired.

Although too far away to see plainly, they thought that he had a small satchel tucked under his arm. As he drew closer they discerned that it was leather, and apparently used as a container for a long cylinder-shaped object.

Passing a short distance away, the man did not see Salt or Penny. They watched until they saw the red glow of his lantern vanish over a hillock.

“That’s the foot-path to the shack where the mines are stored,” Penny commented. “I wonder what’s inside the satchel?”

“Shall we try to find out?”

“Let’s talk to Professor Bettenridge first,” Penny proposed, going down the lane.

The door of the cabin stood slightly ajar. Inside the lighted room were the professor, his wife, Mr. Johnson, and several other persons Penny had never seen before. However, she took them to be town residents who had heard of the test and were eager to see it.

“Well, professor,” they heard Mr. Johnson say jovially. “We’re all here, so why not go ahead? Show us what the machine will do.”

“All in good time, all in good time,” the professor rejoined. “You must give my assistant an opportunity to drop the mine into the lake. He will signal us by lantern when he is ready.”

Penny tapped on the door. The professor whirled around, decidedly startled. Then, observing Salt and Penny, he abruptly came over to speak to them.

“Well?” he asked in a tone which was not friendly.

“We came to see the demonstration,” Penny said brightly.

“Glad to have you,” the professor replied, though without cordiality.

“We want to write a feature story about your machine too,” Penny continued. “For the newspaper.”

The request displeased the professor. Scowling, he said curtly:

“I am sorry, but there must be no publicity at this time—orders of the Navy, you know.”

“The Navy is interested in buying your machine?” Penny asked, hoping to lead him on.

“The deal is concluded except for my signature,” the professor said, darting a quick glance at Mr. Johnson. “I should have signed at once, but I promised Mr. Johnson first chance to buy the machine.”

“I suppose the Navy men are in town now?” Penny inquired.

“In Riverview.”

“At the Gables Hotel?” Penny pursued the subject.

The professor looked at her sharply, for the first time suspecting that she was inducing him to reveal far too much.

Without answering, he turned his back, and began to talk to Mr. Johnson about technical details of the machine.

“I am convinced it is a wonderful invention,” the latter declared. “But before I invest $200,000, I must be absolutely certain that it will do everything you claim.”

“You shall not be disappointed,” reassured the professor. “Only be patient for a few minutes, and you will witness a demonstration that will convince you beyond a shadow of a doubt.”

Ignored by the professor and his wife, Penny and Salt did not enter the cabin. Instead, they walked a short distance away to discuss their next move.

“The demonstration won’t start for a few minutes,” the photographer said. “Suppose we ankle down to the lake and find out what Webb is doing.”

Proceeding down the path which led around the lake shore, they soon sighted the man’s glowing lantern. He had set it down on the ground while he trundled out one of the heavy mines from the shack. As they watched from a distance, he loaded it into a boat, picked up the lantern, and slowly rowed out into the lake.

“Apparently he’s going to drop it overboard for the test,” Salt said. “While he’s out there, let’s take a look in the shack.”

He tried the door. It was locked.

“I don’t know how it’s done, but I’m sure those mines are doctored in some way,” Penny declared. “Louise and I saw Webb working on one when we were here yesterday, but what he did I couldn’t guess.”

“We’ll learn nothing here,” Salt said. “Let’s go back to the cabin and see how the professor pulls off the demonstration. Apparently he has Mr. Johnson two-thirds convinced already.”

“Whatever you do, don’t get into an argument with the professor about your camera until after the test,” Penny pleaded as they started up the slope again. “I want to watch the demonstration. If you accuse him of deliberately keeping the camera, he may throw us out.”

“Okay, I’ll wait,” Salt promised.

Reaching the cabin, the pair became instantly aware of a tenseness in the attitude of the professor and his wife. Although they did not tell the newcomers they were unwelcome, it was evident by their expressions that they distrusted Penny and Salt.

Professor Bettenridge stood behind his machine, explaining its many parts to the awed spectators. Penny could make nothing of the technical jargon.

“The demonstration will soon start,” the professor declared, looking at his watch. “I will turn on the motors now, as they must heat for several minutes.”

He turned several switches and the room was filled with a low humming sound. Two tiny lights buried deep in the complicated mechanism began to glow a cherry red. The professor bent low over the machine, frowning thoughtfully. He adjusted three of the concave mirrors, and switched on another motor.

Despite a dubious attitude, Penny found herself becoming deeply impressed. Was it possible, she wondered, that she had misjudged the professor and his machine? She dismissed the thought. The mine never would explode unless it had been tampered with—she was certain of that.

“Watch closely now,” the professor directed. “At any moment my assistant will signal with his lantern that he has dropped the mine and is safely away from the area.”

The professor’s wife had gone to the doorway. Tensely she watched the lake. Minutes passed. Then from out on the water, there came a moving circle of red—the signal from Webb.

“Now!” exclaimed the professor’s wife.

Everyone in the little cabin held his breath. Dramatically, Professor Bettenridge took a metal tuning fork and struck it sharply against the crystal ball in the center of his machine.

“It will take a moment for the sound to reach the lake,” he said softly. “But only a moment. Watch closely.”

All persons in the room crowded to the door and the windows. Suddenly a huge burst of flame appeared on the lake, fanning out on the surface of the water. A moment later came the dull boom of a terrific explosion.