Nancy sat staring into s.p.a.ce. Then on a sudden hunch she closed the door to the hall and turned off all the lights. She almost yelled aloud in surprise. Drawn in the corner of one note in fluorescent ink was an exact duplicate of the mysterious glowing eye she had seen at the Anderson Museum!

"How strange!" Nancy thought.

She began to wonder whether Ned had put this on the paper sometime before his kidnapping, or if by some ruse he had been able to use certain materials in the cabin's lab.

Then Nancy remembered that one note indicated Ned was not allowed far from his cot. The paper with the glowing eye must have been from a note pad her friend was carrying when he arrived at the isolated cabin.

"The message on the paper doesn't light up, so it probably has nothing to do with the glowing eye," she thought.

Nancy had just turned all the lights back on when the door opened and George and Bess came in.

Instantly Nancy said, "I'll show you something very interesting. Turn off all the lights!"

When Bess and George saw the glowing eye on the paper, they stared in disbelief. Nancy told them she wondered if Ned had put the glowing eye on the sheet as some sort of clue for her.

"What I wish I could do right now is figure out where he is at this moment. Oh dear! We came so close to rescuing him."

Bess put an arm around Nancy. "Don't be sad. We'll track him down yet."

George suggested that the kidnapper probably would bring Ned back to the cabin as soon as he thought it was safe.

"He'll never guess that two officers are there waiting to capture him and set Ned free," she said.

Bess, who had been staring at the glowing eye, asked Nancy if she thought the drawing on the notepaper might indicate something special about his work.

"Yes. I think Ned has invented something unique and tried it out on this paper," Nancy replied as she turned on the light. "It may or may not have anything to do with the glowing eye in the museum. When he found it worked, he began to make a bigger and better one. At that point someone decided to get hold of the invention and put it to his own use, maybe even sell the formula."

Just then Burt and Dave entered the room. At once George suggested that they close the door and turn off the light.

The boys laughed. Dave said, "What's going on?"

"Wait until you see something amazing Nancy found," George replied.

The boys were as astounded at the discovery as the girls had been.

"It may not be long before we hear something important," Bess told the boys. "Ned's kidnapper may go back to that cabin and be captured by the police."

Nancy, however, said she had a different idea.

"What is it, Nancy?" George asked excitedly.

CHAPTER XIII.

The Escape

"HERE is my idea," Nancy said to her waiting friends. "We're sure Crosson uses the old farmhouse. If he's the kidnapper, he might have taken Ned there."

"It's a good guess," George conceded.

Bess suggested that maybe Crosson would put Ned in the clothes chute. No one would be likely to look for a missing person in that spot.

"Another good guess," Dave remarked, smiling at Bess.

George spoke up. "Then we should rescue Ned at once!"

"Yes," Nancy agreed. "And I have another hunch. Crosson may stay there only until early morning. Which of you is game to go with me right now?"

Everyone in the group was eager to leave immediately. Burt did the driving, which gave Nancy a chance to mull over the many angles to the mystery. The red-haired man had outwitted her and she was determined he would not do it again. She sighed, however. He was very clever and surely would try to outsmart them.

"Oh, oh!" Burt burst out. "Look ahead! Blockade!"

By now they were about half a mile from the farmhouse. A wall of piled-up stones stretched across the road. Atop the center of it was a red lantern. Attached below was a large sign which read:DANGER

BLASTING AHEAD.

There was no way to get around the wall at this point because trees grew rather solidly along the road.

Bess asked, "What are we going to do?"

Burt said he would drive around via another road and approach the farmhouse from the opposite direction. It took twenty minutes to do this. When they came within half a mile of the far side of the building, they were confronted with a great pile of brush across the road. The sides had high embankments.

"Stymied again!" George remarked.

"What are we going to do?" Bess asked.

Nancy pointed out the fact that there were no trees along the road in this area. "Let's walk and approach the house through the field," she proposed.

Bess reminded her that it probably would be rough walking. "What's the matter with the road? That's smooth!"

Nancy said it was possible there was some truth in the sign at the stone barrier. The road might be torn up or have unexploded dynamite stored on it. However, she was suspicious that the person who put up the sign and the two barriers had done so to keep visitors away.

"Why not notify the police and let them take care of everything?" Bess suggested.

"But Ned may be a prisoner at the farmhouse," George reminded her. "Well, I'm ready to start. Who's willing to go along? I promise an adventure!"

"I'll wait in the car," Bess said.

Dave decided to stay with her. "It's too dangerous for Bess to be alone here."

The others left them, climbed the embankment on the farmhouse side, and walked through the field. It was bright moonlight, so flashlights were not needed. The rutted ground could be spotted easily, so Burt and the girls had no trouble reaching the farmhouse quickly. They had walked as lightly as possible and not said a word.

The abandoned house was in darkness. As the group skirted a small brook and copse of trees they found themselves approaching the building from the rear.

Suddenly Nancy stopped short and pointed. The others looked ahead. Clearly outlined in the bright moonlight was a helicopter!