"And probably gagged," Nancy added. "Otherwise he'd have yelled for help."

All agreed and hurried along the overgrown path. It was easy to follow the trail because gra.s.s had been trampled where no footprints were evident. Nancy and Art had outdistanced the others. As they turned a corner in the woods both of them could hear water running. In a few moments they came to a deep stream.

"Now what do we do?" Art asked.

Nancy gazed left and right. No footprints or trampled gra.s.s were visible. Had Bob been taken away in a boat?

Holding her hands binocular-fashion around her eyes, Nancy focused on the opposite bank and tried to detect possible footprints. She could see none.

"I'm afraid we're stopped for the time being," she said in disappointment. "Let's retrace our steps and keep looking for clues." They found nothing and in dismay returned to the dig.

"We must notify the State Police," Theresa remarked with mounting concern.

"I'll be glad to do it," Nancy spoke up. "That is, if Art will take me to town. And I want to phone home."

"I'll get the motorcycle."

He brought the vehicle to the front of the house and said to Nancy, "Hop aboard!"

As they neared Walmsley, Art said he thought they should call Bob's house before notifying the police.

"It's possible that he escaped from his captors and is home by now."

Nancy doubted this, but agreed it was a good thing to do. They went to the telephone booth they had used before and Art put in the call. Bob's father was shocked to hear the news. Not only had his son not come home, but he and Mrs. Snell had not heard from him since he had left for the dig site.

"This is alarming," Mr. Snell said to Art. "If I don't hear from Bob or the police soon, I'll notify the FBI. Bob may have been taken out of the state."

Art hung up. Then he dialed State Police Headquarters and handed the phone to Nancy. She reported Bob's disappearance and the fact that the farmhouse near the dig had been visited more than once by an intruder or intruders. "The one last night tried to steal a skeleton," she said.

"We'll look into this whole matter at once," the officer promised. "Men will come to the dig. And if you get any more clues, be sure to let us know."

Nancy agreed to do this and said good-by. As she paused before making her next call, Art asked, "Phoning your dad?"

Nancy shook her head. "I want to tell Ned about the arrangements for the towboat and barge trip."

Art walked off a little distance looking very glum. There was no doubt about it-he was jealous! Nancy hoped there would be no trouble between him and Ned.

It was fully a minute before she reached Ned. "Everything's set," she reported. "Julie Anne and Art and I will meet you tomorrow afternoon at the Delta Motel in Cairo. Toward suppertime we'll go aboard the towboat. It's called the Sally O."

"Sounds great!" Ned replied. "I'll get in touch with the others right away. It sure will be good to see you again, Nancy. It's been a long time."

Nancy smiled. It had been only two weeks! But she was delighted that Ned felt this way and replied, "Yes, it has seemed like ages."

After she had finished talking to him, Nancy phoned her own home. Her lather was not around, so she told Hannah Gruen the news, including the disappearance of Bob Snell.

"That's dreadful," the Drews' housekeeper said, then gave a great sigh. "Nancy, every place you go, it seems as if mysteries just pile up one after another."

"I guess you're right, Hannah dear," the young detective replied. "All of us are terribly worried about Bob. We think he was kidnapped, but n.o.body can figure out why. There's been no ransom demand. His family hasn't a great deal of money, anyway, and certainly Bob doesn't."

"I'll be thinking good thoughts for him," Hannah said. "Let me know the minute he's found."

Hannah also reported that Mr. Drew had been away overnight and would not return until that evening.

Nancy said to give him her love, then went to join Art. Riding back to the dig, he seemed lost in thought. She wondered if he was worrying about Bob Snell or just being foolishly jealous of Ned.

"Would you mind stopping at Clem Rucker's farm?" she inquired. "I asked to have messages for me sent in care of him at the Walmsley post office. There might be one or two."

Art turned onto a side road and the couple bounced along until they reached the elderly farmer's house. He was just coming in from the fields.

"Howdy, folks," he greeted them. "Nancy, I went to the post office this mornin' and picked up a couple o' letters for you. Figgered to bring 'em over later. Wait a minute. I'll get 'em."

He disappeared inside the house but was back in a few seconds with Nancy's mail. She asked if he and Art would mind if she read them.

"No. Go ahead," Clem answered. "I reckon you're curious."

Nancy tore open one of the envelopes. The letter inside was from Roscoe Thompson, the helicopter pilot. He would come to the dig at eleven o'clock the next morning to pick up his three pa.s.sengers. Nancy reported this to Art, who smiled feebly.

The other letter was from Mr. Drew. In it he told of a telephone conversation with his sister in New York. Aunt Eloise had given him some startling news.

The letter read:

"Boycey Osborne is very much concerned about one of his colleagues who was on the detective club trip. This man, A. C. E. Armstrong, left the group to go visit a brother in Rochester, New York. Now Boycey has learned that Armstrong never arrived there. No one has heard from him since he left his friends in Illinois. A search of hospitals has failed to reveal his whereabouts.

"Everyone is extremely worried that Armstrong met with foul play. If you come upon any clues, Nancy, get in touch with Boycey immediately."

Shocked, Nancy read the letter aloud. Art and Clem were disturbed by the news.

"Do you suppose," Art asked, "that he might have been kidnapped and there's some connection between his disappearance and that of Bob Snell?"

"But they didn't know each other," Nancy replied, "and they were on different projects."

Clem wanted to hear more regarding Bob Snell, so they told him the whole story. The farmer said he would certainly keep his eyes open for clues.

When Nancy and Art arrived at the farmhouse, the others were already eating lunch under the trees. The couple reported what they had learned. The girls were aghast at the story of the disappearance of A. C. E. Armstrong and a few of them hinted about going home before the situation became more dangerous.

"I can't say I blame you," Theresa replied. "But you couldn't go before tomorrow. I suggest that hereafter we have guards at both houses day and night."

"May I make a suggestion?" Nancy asked. "There must be some whistles in camp. Why don't we use them to alert one another at a moment's notice?"

"A very good idea," Theresa agreed.

Only two whistles were found. At supper these were given to the two boys who would act as guards that night. Les Blake was to stand watch at the girls' farmhouse.

"Don't hesitate to whistle if you see anything suspicious," Theresa told him as she and the girls went into the house at bedtime.

Nancy and Julie Anne packed their clothes in preparation for the take-off the following morning. Finally they got to bed and all the lanterns and flashlights were extinguished.

Some time later Nancy was awakened by the shrill sounds of a whistle. For a moment she could not figure out why it was being blown, then suddenly she remembered. Les Blake was warning them of danger!