The boys' story had convinced him, but when they had searched the rooms in the tower without success, he showed his disgust.

"It's a hoax!" he snorted. "Adelia was right. I've been made a fool of! And all because of Robinson!"

"I can't understand it!" Joe burst out. "Jackley said he hid the stuff in the tower."

"If that fellow did hide the jewels and bonds in one of the towers," Applegate surmised, "someone else must have come in and taken them-maybe someone working with him. Or else Robinson found the loot right after the robbery and kept it for himself."

"I'm sure Mr. Robinson wouldn't do that," Joe objected.

"Then where did he get the nine hundred dollars? Explain that. Robinson won't!"

On the way back to the main part of the mansion, Hurd Applegate elaborated on his theory. The fact that the loot had not been found seemed to convince him all over again that Robinson was involved in some way.

"Like as not he was in league with Jackley!" the man stated flatly.

Again Frank and Joe protested that the ex-caretaker did not hobn.o.b with criminals. Nevertheless, the Hardys were puzzled, disappointed, and alarmed.

Their search had only resulted in implicating Mr. Robinson more deeply in the mystery.

Back in the hallway of the main house they met Adelia Applegate, who crowed triumphantly when she saw the search party returning empty-handed.

"Didn't I tell you?" she cried. "Hurd Applegate, you've let these boys make a fool of you!"

She escorted the Hardys to the front door, while her brother, shaking his head perplexedly, went back to his study.

"We sure messed things up, Frank," Joe declared, as they walked toward their motorcycles. "I feel like a dud rocket."

"Me too."

They hurried home to tell their father the disappointing news. Fenton Hardy was amazed to hear that the stolen valuables had not been located in either tower. "You're sure you went over the place thoroughly?"

"Every inch of it. There wasn't a sign of the loot. From the dust in the old tower, I'd say no one had been there for ages," Frank replied.

"Strange," the detective muttered. "I'm sure Jackley wasn't lying. He had absolutely nothing to gain by deceiving me. 'I hid it in the old tower.' Those were his very words. And what could he mean but the old tower of Tower Mansion? And why should he be so careful to say the old tower? Since he was familiar with Bayport, he probably knew that the mansion has two towers, the old and the new."

"Of course, it may be that we didn't search thoroughly enough," Joe remarked. "The loot could be hidden under the flooring or behind a movable wall panel. We didn't look there."

"That's the only solution," Mr. Hardy agreed. "I'm still not satisfied that the stolen property isn't there. I'm going to ask Applegate to permit another search of both towers. And now, I think your mother wants you to do an errand downtown."

Mrs. Hardy explained what she wanted and Frank and Joe were soon on their motorcycles again. When the boys reached the business section of Bayport they found that Jackley's confession had already become known.

The local radio station had broadcast it in the afternoon news program and people everywhere were discussing it.

Detective Sm.u.f.f walked along the street looking as if he would bite the head off the first person who mentioned the case to him. When he saw the Hardy boys he glowered.

"Well," he grunted, "I hear you got the stuff back."

"I wish we had," Frank said glumly.

"What!" the detective cried out, brightening at once. "You didn't get it? I thought they said on the radio that this fellow Jackley had told your father where he hid it."

"He did. But how did the news leak out?"

"Jackley's door wasn't closed all the time. One of the other patients who was walking by the room heard the confession and spilled it. So you didn't find the loot after all! Ha-ha! That's a good one! Didn't Jackley say the stuff was hidden in the old tower? What more do you need?"

"Well, it wasn't there!" Joe retorted hotly. "Jackley must have made a mistake!"

"Jackley made a mistake!" Sm.u.f.f continued cheerfully. "It looks like the joke's on you fellows and your father!" The would-be sleuth went on down the street, chuckling to himself.

When Frank and Joe returned home they found that Mr. Hardy had been in touch with Hurd Applegate and had convinced him that a more detailed search of the towers would be advisable.

"Boys," he said, "we'll go there directly after supper. I think we'd better not wait until tomorrow."

At seven o'clock the detective and his sons presented themselves at the Tower Mansion. Hurd Applegate met them at the door.

"I'm letting you make this search," he said as he led them toward the old tower, "but I'm convinced you won't find anything. I've talked the case over with Chief Collig. He's inclined to think that Robinson is behind it all and I'm sure he is."

"But how about Jackley's confession?" Mr. Hardy asked him.

"The chief says that could be a blind. Jackley did it to protect Robinson.

They were working together."

"I know it looks bad for Robinson," Mr. Hardy admitted, "but I want to give the towers another close examination. I heard Jackley make the confession and I don't believe he was lying."

"Maybe. Maybe. But I'm telling you it was a hoax."

"I'll believe that only if I don't find anything inside or outside either tower,"

Mr. Hardy declared, his mouth set in a grim line.

"Well, come on, let's get started," Hurd Apple-gate said, unlocking the door leading to the old tower.

Eagerly the four set to work. They started at the top of the old tower and worked downward. Their investigation left no possibility untouched. All the walls were tapped for hollow sounds which might indicate secret hiding places. The floors were examined closely for signs of any recent disturbance to the wood. But the missing jewels and bonds were not located. Finally the group reached the ground floor again.

"Nothing to do but go on to the new tower," Mr. Hardy commented briefly.

"I'll have to rest and eat something before I do any more," Hurd Applegate said wearily. He led the way to the dining room where sandwiches and milk had been set out. "Help yourselves," he invited. He himself took only crackers and milk when they all sat down.

After the brief stop for refreshment, the Hardys and the mansion owner turned their attention to the new tower. Again they searched carefully. Walls and part.i.tions were tapped and floors were sounded. Every bit of furniture was minutely examined. Not an inch of s.p.a.ce escaped the scrutiny of the detective and his helpers.

As the search drew to a close and the loot still had not been found, Mr. Hardy remarked, "It certainly looks as if the stolen property was never hidden here by Jackley. And furthermore, there's no evidence that if he did hide it here, anyone came in to take it away."

"You mean," said Frank, "it's proof that Mr. Robinson did not come in here?"

"Exactly."

"Maybe not," Mr. Applegate conceded. "But it still doesn't prove he wasn't in cahoots with the thief!"

"I'm not going to give up this search yet," Mr. Hardy said determinedly.

"Perhaps the loot was hidden somewhere outside the old tower."

He explained that it would be difficult to examine the grounds properly at night. "With your permission, Mr. Applegate, my sons and I will return at sunrise tomorrow morning and start work again." As the owner reluctantly nodded his a.s.sent, Mr. Hardy turned to Frank and Joe and smiled. "We ought to be able to prove our point before schooltime."

The boys, who had had no time to prepare any homework, reminded their father that a note from him to the princ.i.p.al would be a great help. The detective smiled, and as soon as they reached home he wrote one out, then said good night.

Frank and Joe felt as if their eyes had hardly closed when they opened them again to see their father standing between their beds. "Time to get up if you want to be in on the search," he announced.

The boys blinked sleepily, then sprang out of bed. Showers awakened them fully and they dressed quickly. Mrs. Hardy was in the kitchen when they entered it and breakfast was ready. The sun was just rising over a distant hill.

"Everything hot this morning," Mrs. Hardy said. "It's chilly outside."

The menu included hot applesauce, oatmeal, poached eggs on toast, and cocoa. Breakfast was eaten almost in silence to avoid any delay, and within twenty minutes the three Hardy sleuths were on their way.

"I see you put spades in the car, Dad," Frank remarked. "I take it we're going to do some digging."

"Yes, if we don't locate the loot hidden above ground some place."

When the Hardys reached Tower Mansion they inst.i.tuted their hunt without notifying the Apple-gates, who, they were sure, were still asleep. Everything in the vicinity of both towers was scrutinized. Boulders were overturned, the s.p.a.ce under the summerhouse examined by flashlight, every stone in the masonry tested to see if it could be dislodged. Not a clue turned up.

"I guess we dig," Frank stated finally.

He chose a bed of perennial bushes at the foot of the old tower where there had been recent planting, and pushed one of the spades in deep with his foot.

The tool hit an obstruction. Excitedly Frank shoveled away the dirt around the spot. In half a minute he gave a cry of delight. "A chest! I've found a buried chest!"

CHAPTER XVII.

An Unexpected Find THROWING out the dirt in great spadefuls, Frank uncovered the chest completely. It was about two feet long, six inches wide, and a foot deep.

"The treasure!" Joe cried out, running up.

Mr. Hardy was at his son's heels and looked in amazement at Frank's discovery. The boy lifted the chest out of the hole and instantly began to raise the lid on which there was no lock.

Everyone held his breath. Had the Hardys really uncovered the jewels and securities stolen from the Applegates? Frank flung back the lid.

The three sleuths stared at the contents. They had never been more surprised in their lives. Finally Joe found his voice.

"Nothing but a lot of flower bulbs!"

The first shock of disappointment over, the detective and his sons burst into laughter. The contents of the chest were such a far cry from what they had expected that now the situation seemed ridiculous.

"Well, one thing is sure," said Frank. "Red Jack-ley never buried this chest.

I wonder who did?"

"I can answer that," a voice behind them replied, and the Hardys turned to see Hurd Apple-gate, clad in bathrobe and slippers, walking toward them.

"Good morning, Mr. Applegate," the boys chorused, and their father added, "You see we're on the job. For a couple of moments we thought we had found your stolen property."

Hurd Applegate's face took on a stern look. "You didn't find my securities,"

he said, "but maybe you have found a clue to the thief. Robinson buried that chest full of bulbs. That's what he's done with Adelia's jewelry and my securities! He's buried them some place, but I'd be willing to bet anything it wasn't on the grounds here."

Frank, realizing the man was not in a good humor this morning, tried to steer the conversation away from the stolen valuables. "Mr. Applegate," he said, "why did Mr. Robinson bury these flower bulbs here?"

The owner of Tower Mansion gave a little snort. "That man's nutty about unusual flowers. He sent to Europe for these bulbs. They have to be kept in a cool, dark place for several months, so he decided to bury them. He's always doing something queer like that. Why, do you know what he tried to get me to do? Put up a greenhouse here on the property so he could raise all kinds of rare flowers."

"That sounds like a swell hobby," Joe spoke up.

"Swell nothing!" Mr. Applegate replied. "I guess you don't know how much greenhouses cost. And besides, growing rare flowers takes a lot of time.

Robinson had enough to do without fiddling around with making great big daisies out of little wild ones, or turning cowslips into orchids!"

Frank whistled. "If Mr. Robinson can do that, he's a genius!"

"Genius-that's a joke!" said Mr. Applegate. "Well, go on with your digging. I want this mystery cleared up."

It was decided that Mr. Hardy, with his superior powers of observation, would scrutinize the ground near both towers. Wherever it looked as if the ground had been turned over recently, the boys would dig at the spot. The chest of flower bulbs was carefully replaced and the dirt shoveled over it.

"Here's a place where you might dig," Mr. Hardy called presently from the opposite side of the old tower. When the boys arrived with their spades, he said, "I have an idea a dog dug up this spot and probably all you'll find is a beef bone. But we don't want to miss anything."

This time Joe's spade hit the object which had been buried. As his father had prophesied, it proved to be only a bone secreted by some dog.

The three Hardys transferred their work to the new tower. All this time Hurd Applegate had been looking on in silence. From the corners of their eyes, the Hardys could catch an expression of satisfaction on the elderly man's face.

Mr. Hardy glanced at his wrist watch, then said, "Well, boys, I guess this is our last try." He indicated another spot a few feet away. "You fellows must get cleaned up and go to school."

Undaunted by their failures so far, Frank and Joe dug in with a will. In a few moments they had uncovered another small chest.

"Wow, this one is heavy!" Frank said as he lifted it from the hole.

"Then maybe-maybe it's the stolen property!" Joe exclaimed.

Even Mr. Applegate showed keen interest this time and leaned over to raise the lid himself. The box contained several sacks.

"The jewels!" Joe cried out.

"And that flat-shaped sack could contain the securities!" Frank said enthusiastically.

Mr. Applegate picked up one of the circular bags and quickly untied the string wound about the top. His face took on a look of utter disgust. "Seeds!"