One side of the pa.s.sageway was set with square stone columns. Heavy vines grew up and over them, forming a roof of leaves through which sun- light filtered into the cool tunnel. The other side was a high crumbling fieldstone wall with deep alcoves about twenty-five feet apart.

"Just like the picture we saw in the book!" Bess said. "Oh, what an attractive walk to the beach!"

"Now to find the hidden treasure," George said. "Come on!"

Hopefully the girls examined the niches along the wall, some of which had built-in stone shelves.

In one, a statuette lay on its side; in another, a vase had tipped over and broken.

George felt among the vines. "Nothing here-"

she started to say when Nancy interrupted her.

She held up a finger in warning.

"Listen!" she whispered.

The three girls stood still. Faintly they heard men's voices from the other side of the wall. They stole along the flagstones cautiously, hardly daring to breathe. As they reached another niche, the deep voices came to them distinctly.

"This looks like a good spot!" one man said, making no attempt to speak low. "Bring your pick, Cobb."

Nancy recognized the voices. She had heard them the night of her imprisonment in the tower!

The men started to work with chisel, pick, and sledgehammer. Tiny stones and bits of mortar rattled down at the girls' feet.

"They're wrecking this lovely wall!" George whispered indignantly.

Just then a decorative ledge in the alcove came loose and threatened to crash to the flagstone floor. Quickly Nancy stepped forward and caught the slab. With Bess's help, she laid it carefully on the ground.

Nancy straightened up and gasped as she looked at the wall niche. Where the ledge had been, a long, narrow pocket was now exposed!

Nancy ran her hand into the dark opening.

Her groping fingers touched something cold and hard.

A metal box!

"Nancy!" George warned in a whisper.

Directly above the girl's hand a stone chisel was poking through the wall. In another moment the men would succeed in making a large opening into the niche!

Nancy drew out the flat metal box, then the three girls turned and fled through the cloister toward the castle. The sound of the men working gradually died away.

"We're safe!" Nancy exclaimed. "Now let's open the box!"

Her hands trembled with excitement as she lifted the lid of the rusty container.

"Hm!" said George. "Only papers and photo- graphs."

Bess, too, was disappointed. "There's nothing valuable here I And after all our trouble, too!"

"Let's not be too hasty," Nancy advised, and lifted out the top photograph carefully. Yellowed with age, it showed a middle-aged man in old- fashioned clothes. At the bottom was scrawled the name "Ira Heath," and a date.

Nancy was about to hand the picture to George when a detail of the man's clothing attracted her attention. A watch chain which hung from Mr.

Heath's vest pocket had an unusual charm at- tached to it!

"Look at this!" she said. "I saw the very same charm at Sam Weatherby's curio shop. Daniel Hector sold it to him along with some other jewelry!"

"You're kidding!" Bess exclaimed.

"No. Hector told Mr. Weatherby the jewelry was from his own family."

"That certainly sounds suspicious," George said, reaching for another photograph. She held up the picture of a sweet-faced woman, wearing a long gown and upswept hair. An inscription identified her as Heath's wife, Ida.

"Her earrings!" Nancy said. "Hector sold those to Mr. Weatherby, too!"

"He has been robbing the estate!" Bess de- clared.

There were more pictures in the box, but none were of particular interest to the girls. Under- neath the pile was a small leather-bound diary.

The flyleaf bore Walter Heath's name, and the dates of many of the notations showed they had been made less than a month before his death.

"This may be the most valuable thing in this box!" Nancy remarked, skimming through the book. Many of the pages were blank, but under one date was an item important enough to read aloud.

"I stumbled upon something which may prove to be a treasure. In the salted pond there are many marine mollusks placed there by my father.

They not only have beautiful sh.e.l.ls, but their glands give off a purple dye. I am mixing it with certain chemicals and so far have produced six shades of purple dye. But the color does not last.

I will keep trying for a perfect formula."

"I wonder it he did perfect it and what became of the formula," Bess mused.

"Good question," said George.

Nancy turned more pages in the diary. "Here's something," she said. "Listen to this: " 'I don't trust the new chauffeur Biggs. Have decided to hide all the bottles of dye until my ex- periments are complete.' "

"Does it say where he hid them?" George asked.

"Read the next page."

"There's nothing more. This is the last para- graph in the book."

"What a shame!"

"Maybe we'll find other clues when we read the entire diary," Nancy said. "But there's no time now."

"I'll say there isn't!" George agreed. "Sh! We'd better duck out of here and fast!"

From just across the stone barrier came the barking of a dog. Voices were audible, and each moment they grew louder. The two men were approaching!

"How about looking on the opposite side of this wall?" one of them asked.

"Okay," the other man replied. "May as well climb over and make a good job of it while we're here."

Fearful of being seen, the girls tiptoed along the cloister wall. Nancy carried the metal box, which was heavy.

"We should have gone the other way, toward the beach," she whispered. "I hope we don't get trapped!"

As they rounded a curve the girls noticed that the cloister ended abruptly in a rear wall of the castle, with a huge wooden door. It was locked!

Nancy tried her key. It would not fit!

"Oh, what'll we do?" Bess asked. "This is awfull!"

The men could be heard moving slowly up the flagstone pa.s.sageway. In a moment or two they certainly would see the girls.

"Nancy, we'll have to hide the box!" George said.

"We'd better hide ourselves," Bess urged.

"Maybe we could break through the vines,"

Nancy suggested.

"No chance," George decided. "There's a net- work of thick stalks between the pillars. I touched them before when we were searching tor the treasure."

Not far from the castle wall was a large nook.

In their haste the girls had pa.s.sed it with only a fleeting glance. Now Nancy thought that it might make a safe hiding place.

"Follow me!" she directed.

Above the arched entrance to the refuge had been chiseled the words Poet's Nook, but the girls scarcely noticed it as they slipped into the niche.

"I must hide this box so the men can't take it, even if they catch us," Nancy declared grimly.

Frantically the girls looked about them. Nancy noticed a loose stone in the wall directly above a bench in the back of their hiding place.

"George," she said, "see if it will move."

Luckily the stone could be eased out. A large, empty s.p.a.ce was behind it. Nancy slipped the box inside, and George quickly fitted the stone into place.

By this time the men were very near, and had stopped walking. "How about working in the Poet's Nook?" one asked suddenly. "Maybe we'll find something there."

The girls flattened themselves against the wall and waited tensely, scarcely daring to breathe.

"We looked there once. That hiding place over the bench was empty."

"Sure, but it we take out the whole wall, we might find another one. You're lazy if you ask me."

"Did I ask you?" the first man growled. "This is hard work. We're not getting much money for it either."

The other laughed. "What we found already is good enough pay for me. And if we find the other loot, we can live anyway we please."

Nancy and her friends surmised that the men would not search the Poet's Nook again and re- laxed slightly. But their hopes were dashed.

"How about it, Cobb?" the first man de- manded. "Do we take out the wall or don't we?"

"Okay," the one addressed as Cobb replied.

"You go ahead. I'll be with you in a minute.

Here's the sledgehammer."

CHAPTER XIV.

Cinderella's Slipper.

Nancy, Bess, and George retreated deeper into the shadows, but their hearts sank. The men were sure to find them!

"I'll be right there, Biggs," Cobb called. "Just want to see if there's anything hidden in any of these other niches."

Biggs! The name electrified the girls. Hadn't Walter Heath mentioned the name Biggs in the diary as that of a suspicious person? Could he be the chauffeur, searching, perhaps, for the bottles of dye his former employer had hidden?

The next moment a tall figure appeared in the entrance of the niche with a sledgehammer. His back was turned to the girls as he called out: "Hurry up! I'm not going to do the heavy work alone!"

At that instant the sound of running footsteps could be heard. Startled, the speaker moved off in their direction.

Nancy tiptoed forward and peered out. Biggs was the man who had signaled from the tower!

Then she saw a boy who was racing toward the two men. Teddy Hooper!

"Hey, come quick!" he shouted. "I've got something to show you!"

Cobb was irritated. "You again!" he exclaimed.

"We told you to keep away from here!"

"But I've got something to tell you!"

"What is it?"