Now the parts to the puzzle were falling into place! Bauxite was the precious mineral the gang hoped to extract from the clay! And Ben was the signer of the telegram Klenger had received-apparently the leader of the gang! He was the man who had arrived at the rendezvous off Merriam Island the night Frank had tried to overhear the conference from the tender of Sweeper"s speedboat.
"We"d better go back and notify the police," Bob whispered. He turned to Frank and Joe. "Maybe 197 your dad"s back from Washington and can take charge."
The two youths and the engineers rose noiselessly from their hiding place and started down toward the subterranean pa.s.sage. Before they had taken ten steps, they were confronted by a man carrying a deadly looking revolver. It was the stranger Frank and Joe had seen helping Hawkins carry the groceries!
"Get going!" he ordered, motioning with the gun toward the cavern room beyond.
CHAPTER XXIV.
Dr. Foster Explains k.lenger and Ben Stoper stared as the Hardy boys and the engineers were herded into the room.
"Where"d you find them?" Stoper demanded of the man who held the gun.
The man jerked his head. "Just outside-in the runway," he replied.
Klenger"s face hardened. "How"d you confounded snoops locate the tunnel?" he asked the boys harshly.
"Rockslide," Frank told him.
The man"s eyes narrowed with disbelief.
"Don"t hand me that," he said sharply.
"It"s true," Joe put in. "It tore away the curtain of foliage at the mouth of the tunnel. If this cavern weren"t so deep underground, you"d have heard it."
Stoper turned to the boys" captor.
"Give me that gun," he directed. He pointed it at the four prisoners. "Now, take a look and see if these kids are telling the truth."
198.
199 The man nodded and hurried out of the cave.
"You"re wasting time," Klenger told Stoper. "It"s true or they wouldn"t be here. They"d never have located the pa.s.sage any other way."
Stoper"s mouth twisted bitterly.
"This is the finish," he told the stocky, redheaded plumber. "Now anybody can walk in here and see what we"re doing!"
Klenger smiled soothingly. "No use to get upset, Ben," he said. "There"s n.o.body around this part of the mountain except them." He jerked his thumb at the prisoners. "We"ll camouflage the hole with loose rock before anybody else has a chance to see it!"
The smaller man appeared to be somewhat mollified.
"Hawkins!" he called. He gave the ex-sailor the gun and nodded toward the prisoners.
"Take them into the bay and tie them up."
The two youths, Bob and d.i.c.k were marched into the small room which adjoined the cavern. It was this room from which Klenger and Stoper had emerged a short time before.
The prisoners were ordered to lie on their stomachs on the damp floor of the darkened room, then their hands and feet were securely tied.
Minutes dragged into hours. The boys and the engineers had discussed every possibility of escape soon after they were imprisoned in the cell, but now had subsided into worried silence, each occupied 200 with his own thoughts. What Klenger would do with them, they did not dare guess. But one thing was certain: he would not allow them to go free and expose his plans.
After what seemed an eternity, they heard footsteps approaching the room in which they were imprisoned. A moment later Hawkins appeared-marching Dr. Foster before him at gun point!
Directing the scientist to lie on the floor, he quickly proceeded to tie his hands and feet.
Frank rolled on his side and looked at the white-haired man as Hawkins clumped out of the room.
"What happened?" he asked.
"I ascertained that there is no bauxite contained in the clay," the scientist replied with dry humor. "So they have no further use for me."
He twisted on his side so he could see his fellow prisoners.
"No doubt you"re all wondering why I"m mixed up with these reckless men," he went on.
"It appears we shan"t be too occupied during the next half hour, so perhaps what I say will help to pa.s.s the time."
Several years ago, he told them, before Tarnack Dam had even been blueprinted, he had prospected for bauxite on Skull Mountain. He had read the geological theory of the subterranean pa.s.sage but believed it to be fiction until, poking along the hillside-then densely forested-he had come upon the 201 mouth of the tunnel about twenty or twenty-five feet up fi Dm the river bed.
"I explored the tunnel with great excitement," the scientist said, "and discovered deposits of clay which seemed to contain the mineral I was searching for."
He coughed, chilled by the damp floor, then continued.
"Deep inside the mountain, I found the cavern, and a cleft running clear to the top of the ridgeJ I-gentlemen, I felt as if I had stumbled upon one of the geological miracles of prehistoric times!"
His voice shook with remembrance of the experience.
"How do Klenger and Stoper fit into this?" Joe asked.
Klenger, Dr. Foster explained, had been recommended to him as a man who could raise money to work the clay deposits in the tunnel. The scientist had told Klenger he was not positive the clay contained bauxite but wanted an opportunity to test the substance and find out.
Klenger had been tremendously interested in the project, and persuaded Dr. Foster to show him the tunnel. But the plumber failed to raise the money, and plans for developing the vein of bauxite had to be abandoned.
"Then, about five weeks ago," the scientist went on, "I received a telegram from Klenger. He told 202 me a group of men headed by Ben Stoper had agreed to put up the money for the project. He insisted that I come to Bayport at once."
Dr. Foster"s voice became bitter.
"I took a leave of absence from my work and joined Klenger. We came here and began to break down the clay. Then I discovered I was no longer a partner in the project-but a prisoner! That all Klenger and the others wanted me for was to make the tests to confirm the presence of the bauxite!"
"And to keep the valley clear to mine the stuff once it was discovered to be bauxite,"
Bob said, "Klenger had to keep the reservoir from filling up."
The scientist nodded.
"He persuaded Hawkins to build the wooden lock," he explained. "The old sailor was highly incensed at the prospect of losing his home because of the water project, and Klenger found him a willing ally in his scheme to divert the water to the sea."
"Where does Potato Annie fit in the picture?" asked Bob.
Dr. Foster said that Potato Annie had helped the gang for the same reason-supplying them with fresh vegetables from her garden.
"What about that s.h.a.ggy old guy?" Frank asked.
"Yes," Joe said grimly. "We"ve plenty of things to settle with him!"
Dr. Foster coughed gently.
"I can well imagine how you feel about Tom 203 Darby," he said, "but I hope you won"t hold him responsible for all of his actions. He"s devoted to me-and terrified of the others. He told me Klenger threatened to send him back to the county farm if he did not obey orders. Otherwise, I"m sure he would have helped me to escape."
"Who is the old fellow?" d.i.c.k wanted to know.
Tom Darby was, in truth, a hermit, the scientist told them. He had run away from the county poor farm in the adjoining state, and had hidden on the mountain.
"I met Tom on my first trip to Skull Mountain," Dr. Foster declared. "He was half starved and nearly naked. But when I tried to help him, he thought I meant to take him back to the poor farm-and ran away."
The scientist smiled at his recollection of the s.h.a.ggy-haired scarecrow fleeing down the mountainside.
"Later, I won the old fellow"s confidence," he went on, "and from then on, Tom couldn"t do enough for me. When I returned this summer, he was still here-and he remembered me.
He lived in the tunnel, and from what I can gather he had been subsisting pretty much on raw vegetables from Annie"s garden, with an occasional handout from one of the other squatters.
He used to steal also from the contractors" stores when they were working on the dam." Dr.
Foster"s eyes twinkled. "It was 204 Tom"s idea to frighten you with skulls. Klenger told Tom anything he did to scare you away from the mountain would be of great help to me!"
"Tom must think an awful lot of you, sir," Joe said ruefully. He certainly did his best to get rid of us!"
d.i.c.k interrupted. "Boulders, an explosion, a Hre-"
"I"m afraid the old fellow was overzealous in his efforts to keep you people away from this region," the scientist said. "It was Sweeper who supplied Tom with the dynamite. And it was Klenger who let fire to your shack. Darby wouldn"t commit mur-vier any more than I would."
He stopped speaking, for at that moment Klenger came into the bay and set a lantern on the floor in front of him. He looked around at them with a thin smile, savoring the suspense his entrance had caused, then his mouth hardened.
"Foster"s probably told you our job is finished," he said harshly. "We"re pulling out."
Frank and Joe looked hopefully at one another, but their hopes were soon dashed.
"Before we go," Klenger was saying, "I"m going to fix it so you won"t be able to tell your story to the cops."
He stopped to make sure that all the prisoners were paying attention to what he was saying.
"One way to do it," he continued, "would be to 205 dump you in the sluiceway and open up the gates. Maybe your bodies would, reach Barmet Bay-and maybe they wouldn"t."
He stared at them thoughtfully.
"Trouble is," he said finally, "I can"t afford to take chances. So I"m goin" to have Hawkins dynamite the mouth of the tunnel and close it up. Thaf, way n.o.body"ll ever know what happened to you."
He picked up the lantern and turned away with a sardonic grin.
"After the tunnel"s shut off," he said, "there won"t be any more trouble getting the water to rise in the reservoir. Some Bayport folks-but not all-will be getting plenty of water from now on!"
CHAPTER XXV.
Smoked Out.
klenger"s words echoed hollowly in the s.p.a.ce the trussed-up prisoners lay.
They stared at one another, but nothing was said. Nothing needed to be said. Their faces, pale and tense, spoke eloquently for them.
They heard Klenger in the cavern instructing Hawkins in the use of the dynamite.
Then Frank remembered the crevice.
"We"ve still got a chance!" he whispered to the others. "If we can only break out of these ropes, we can climb the shaft and escape through the top of the mountain!"
But almost as if he had heard the boy"s words, Klenger cut off their last means of escape.
"After you"ve blasted the mouth of the tunnel," the red-haired man told Hawkins, "come back here and set off another charge to plug the shaft that leads to the ridge. That"ll shut off the crevice and seal everything nice and tight."
207 "Aye, cap"n," the sailor replied. "But how are we to get away?"
"Up the shaft, you fool. Stoper an" me"ll start up toward the ridge while you blow the tunnel. You"ll follow after you"ve blasted the shaft right here where it joins the cavern. Now get going."
The prisoners heard the sailor"s footsteps recede, then there was silence. They struggled desperately with the ropes that bound them. Unless they could break free in the few minutes remaining before Hawkins set off his charge, they would be buried alive!
They rolled close to one another, their fingers tearing at each other"s ropes-but the strands were wet from the damp floor and resisted the prisoners" frantic attempts to untie them.
"There must be some way out of this!" Bob said desperately.
He lifted his wrists to a jagged edge of rock, and awkwardly tried to saw through the binding hemp, but gave up, exhausted.
At that moment the hermit, Darby, staggered into the cavern from the shaftway, his arms piled with firewood. He stared into the prisoners" room, then dropped his load of wood and came quickly to where Dr. Foster was lying on the ground.
"Tom!" the scientist exclaimed. He waggled his hands behind his back. "Hurry, Tom!"