Chapter XI. The Wireless Detective
 

Del Mar made his way cautiously along the bank of a little river at the mouth of which he left the boat after escaping from the little steamer.

Quite evidently he was worried by the failure to cut the great Atlantic cable and he was eager to see whether any leak had occurred in the organization which, as secret foreign agent, he had so carefully built up in America.

As he skirted the shore of the river, he came to a falls. Here he moved even more cautiously than before, looking about to make certain that no one had followed him.

It was a beautiful sheet of water that tumbled with a roar over the ledge of rock, then raced away swiftly to the sea in a cloud of spray.

Assured that he was alone, he approached a crevice in the rocks, near the falls. With another hasty look about, he reached in and pulled a lever.

Instantly a most marvellous change took place, incredible almost beyond belief. The volume of water that came over the falls actually and rapidly decreased until it almost stopped, dripping slowly in a thin veil. There was the entrance of a cave--literally hidden behind the falls!

Del Mar walked in. Inside was the entrance to another, inner cave, higher up in the sheer stone of the wall that the waters had eroded. From the floor to this entrance led a ladder. Del Mar climbed it, then stopped just inside the entrance to the inner cave. For a moment he paused. Then he pressed another lever. Almost immediately the thin trickle of water grew until at last the roaring falls completely covered the cave entrance. It was a clever concealment, contrived by damming the river above and arranging a new outlet controlled by flood-gates.

There Del Mar stood, in the inner cave. A man sat at a table, a curious gear fastened over his head and covering his ears. Before him was a huge apparatus from which flared a big bluish-green spark, snapping and crackling above the thunder of the waves. From the apparatus ran wires apparently up through cables that penetrated the rocky roof of the cavern and the river above.

It was Del Mar's secret wireless station, close to the hidden submarine harbor which had been established beneath the innocent rocks of the promontory up the coast. Far overhead, on the cliff over the falls, were the antennae of the wireless.

"How is she working?" asked Del Mar.

"Pretty well," answered the man.

"No interference?" queried Del Mar, adjusting the apparatus.

The man shook his head in the negative.

"We must get a quenched spark apparatus," went on Del Mar, pleased that nothing was wrong here. "This rotary gap affair is out of date. By the way, I want you to be ready to send a message, to be relayed across to our people. I've got to consult the board below in the harbor, first, however. I'll send a messenger to you."

"Very well, sir," returned the man, saluting as Del Mar went out.

Out at Fort Dale, Lieutenant Woodward was still entertaining his new friend, Professor Arnold, and had introduced him to Colonel Swift, the commanding officer at the Fort.

They were discussing the strange events of the early morning, when an orderly entered, saluted Colonel Swift and handed him a telegram. The Colonel tore it open and read it, his face growing grave. Then he handed it to Woodward, who read:

WASHINGTON, D. C.

Radio station using illegal wave length in your vicinity. Investigate and report.

BRANDON,

Radio Bureau.

Professor Arnold shook his head slowly, as he handed the telegram back. "There's a wireless apparatus of my own on my yacht," he remarked slowly. "I have an instrument there which I think can help you greatly. Let's see what we can do."

"All right," nodded Colonel Swift to Woodward. "Try."

The two went out and a few minutes later, on the shore, jumped into Arnold's fast little motor-boat and sped out across the water until they swung around alongside the trim yacht which Arnold was using.

It was a compact and comfortable little craft with lines that indicated both gracefulness and speed. On one of the masts, as they approached, Woodward noticed the wireless aerial. They climbed up the ladder over the side and made their way directly to the wireless room, where Arnold sat down and at once began to adjust the apparatus.

Woodward seemed keenly interested in inspecting the plant which was of a curious type and not exactly like any that he had seen before.

"Wireless apparatus," explained Arnold, still at work, "as you know, is divided into three parts, the source of power, the making and sending of wireless waves, including the key, spark, condenser and tuning coil, and the receiving apparatus--head telephones, antennae, ground and detector. This is a very compact system with facilities for a quick change from one wave length to another. It has a spark gap, quenched type, break system relay--operator can hear any interference while transmitting--transformation by a single throw of a six-point switch which tunes the oscillating and open circuits to resonance."

Woodward watched him keenly, following his explanation carefully, as Arnold concluded.

"You might call it a radio detective," he added.

Even the startling experience of the morning when she was carried off and finally jumped from the little tramp steamer that had attempted to cut the cable did not dampen Elaine's ardor. She missed the guiding hand of Kennedy, yet felt impelled to follow up and investigate the strange things that had been happening in the neighborhood of her summer home since his disappearance.

I succeeded in getting her safely home after Burnside and I rescued her in the hydroaeroplane, but no sooner had she changed her clothes for dry ones than she disappeared herself. At least I could not find her, though, later, I found that she had stolen away to town and there had purchased a complete outfit of men's clothes from a second hand dealer.

Cautiously, with the large bundle under her arm, she returned to Dodge Hall and almost sneaked into her own home and up-stairs to her room. She locked the door and hastily unwrapped the bundle taking out a tattered suit and the other things, holding them up and laughing gleefully as she took off her own pretty clothes and donned these hideous garments.

Quickly she completed her change of costume and outward character. As she surveyed herself in the dainty mirror of her dressing-table she laughed again at the incongruity of her pretty boudoir and the rough men's clothes she was wearing. Deftly she arranged her hair so that her hat would cover it. She picked a black mustache from the table and stuck it on her soft upper lip. It tickled and she made a wry face over it. Then she hunted up a cigarette from the bundle which she had brought in, lighted it and stuck it in the corner of her mouth, letting it droop jauntily. It made her cough tremendously and she threw it away.

Finally she went to the door and down-stairs. No one was about. She opened the door and gazed around. All was quiet. It was a new role for her, but, with a bold front, she went out and passed down to the gate of the grounds, pulling her hat down over her eyes and assuming a tough swagger.

Only a few minutes before, down in the submarine harbor, the officers of the board of foreign agents had been grouped about Del Mar, who had entered and taken his place at their head, very angry over the failure to cut the cable. As they concluded their hasty conference, he wrote a message on a slip of paper.

"Take this to our wireless station," he ordered, handing it to one of the men.

The man took it, rose, and went to a wardrobe from which he extracted one of the submarine suits. With the message in his hand, he went out of the room, buckling on the suit.

A few minutes later the messenger in the submarine suit bobbed up out of the water, near the promontory, and climbed slowly over the rocks toward a crevice, where he began to take off the diving outfit.

Having finished, he hid the suit among the rocks and then went along to the little river, carefully skirting its banks into the ravine in which were the falls and the wireless cave.

In her disguise, Elaine had made her way by a sort of instinct along the shore to the rocky promontory where we had discovered the message in the tin tube in the water.

Something, she knew not what, was going on about there, and she reasoned that it was not all over yet. She was right. As she looked about keenly she did see something, and she hid among the rocks. It was a man, all dripping, in an outlandish helmet and suit.

She saw him slink into a crevice and take off the suit, then, as he moved toward the river ravine, she stole up after him.

Suddenly she stopped stark still, surprised, and stared.

The man had actually gone up to the very waterfall. He had pressed what looked like a lever and the water over the falls seemed to stop. Then he walked directly through into a cave.

In the greatest wonder, Elaine crept along toward the falls. Inside the cave Del Mar's emissary started to climb a ladder to an inner cave. As he reached the top, he glanced out and saw Elaine by the entrance. With an oath he jumped into the inner entrance. His hand reached eagerly for a lever in the rocks and as he found and held it, he peered out carefully.

Elaine cautiously came from behind a rock where she had hidden herself and seeing no one apparently watching, now, advanced until she stood directly under the trickle of water which had once been the falls. She gazed into the cave, curiously uncertain whether she dared to go in alone or not.

The emissary jerked fiercely at the lever as he saw Elaine.

Above the falls a dam had been built and by a system of levers the gates could be operated so that the water could be thrown over the falls or diverted away, at will. As the man pressed the lever, the flood gates worked quickly.

Elaine stood gazing eagerly into the blackness of the cave. Just then a great volume of water from above crashed down on her, with almost crushing weight.

How she lived through it she never knew. But, fortunately, she had not gone quite far enough to get the full force of the water. Still, the terrific flood easily overcame her.

She was swept, screaming, down the stream.

       .       .       .       .       .       .       .

Rather alarmed at the strange disappearance of Elaine after I brought her home, I had started out along the road to the shore to look for her, thinking that she might perhaps have returned there.

As I walked along a young tough--at least at the time I thought it was a young tough, so good was the disguise she had assumed and so well did she carry it off--slouched past me.

What such a character could be doing in the neighborhood I could not see. But he was so noticeably tough that I turned and looked. He kept his eyes averted as if afraid of being recognized.

"Great Caesar," I muttered to myself, "that's a roughneck. This place is sure getting to be a hang-out for gunmen."

I shrugged my shoulders and continued my walk. It was no business of mine. Finding no trace of Elaine, I returned to the house. Aunt Josephine was in the library, alone.

"Where's Elaine?" I asked anxiously.

"I don't know," she replied. "I don't think she's at home." "Well, I can't find her anywhere," I frowned wandering out at a loss what to do, and thrusting my hands deep in my pockets as an aid to thought.

Somehow, I felt, I didn't seem to get on well as a detective without Kennedy. Yet, so far, a kind providence seemed to have watched over us. Was it because we were children--or--I rejected that alternative.

Walking along leisurely I made my way down to the shore. At a bridge that crossed a rather turbulent stream as it tumbled its way toward the sea, I paused and looked at the water reflectively.

Suddenly my vagrant interest was aroused. Up the stream I saw some one struggling in the water and shouting for help as the current carried her along, screaming.

It was Elaine. The hat and mustache of her disguise were gone and her beautiful Titian hair was spread out on the water as it carried her now this way, now that, while she struck out with all her strength to keep afloat. I did not stop to think how or why she was there. I swung over the bridge rail, stripping off my coat, ready to dive. On she came with the swift current to the bridge. As she approached I dived. It was not a minute too soon. In her struggles she had become thoroughly exhausted. She was a good swimmer but the fight with nature was unequal.

I reached her in a second or so and took her hand. Half pulling, half shoving her, I struck out for the shore. We managed to make it together where the current was not quite so strong and climbed safely up a rock.

Elaine sank down, choking and gasping, not unconscious but pretty much all in and exhausted. I looked at her in amazement. She was the tough character I had just seen.

"Why, where in the world did you get those togs?" I queried.

"Never mind my clothes, Walter," she gasped. "Take me home for some dry ones. I have a clue."

She rose, determined to shake off the effects of her recent plunge and went toward the house. As I helped her she related breathlessly what she has just seen.

Meanwhile, back of that wall of water, the wireless operator in the cave was sending the messages which Del Mar's emissary dictated to him, one after another.

       .       .       .       .       .       .       .

With the high resistance receiving apparatus over his head, Arnold was listening to the wireless signals that came over his "radio detective" on the yacht, moving the slider back and forth on a sort of tuning coil, as he listened. Woodward stood close beside him.

"As you know," Arnold remarked, "by the use of an aerial, messages may be easily received from any number of stations. Laws, rules, and regulations may be adopted by the government to shut out interlopers and to plug busybody ears, but the greater part of whatever is transmitted by the Hertzian waves can be snatched down by this wireless detective of mine. Here I can sit in my wireless room with this ear-phone clamped over my head drinking in news, plucking the secrets of others from the sky--in other words, this is eavesdropping by a wireless wire-tapper."

"Are you getting anything now?" asked Woodward.

Arnold nodded, as he seized a pencil and started to write. The lieutenant bent forward in tense interest. Finally Arnold read what he had written and with a peculiar, quiet smile handed it over. Woodward read. It was a senseless jumble of dots and dashes of the Morse code but, although he was familiar with the code, he could make nothing out of it.

"It's the Morse code all right," he said, handing it back with a puzzled look, "but it doesn't make any sense."

Arnold smiled again, took the paper, and without a word wrote on it some more. Then he handed it back to Woodward. "An old trick," he said. "Reverse the dots and dashes and see what you get."

Woodward looked at it, as Arnold had reversed it and his face lighted up.

"Harbor successfully mined," he quoted in surprise.

"I'll show you another thing about this radio detective of mine," went on Arnold energetically. "It's not only a wave length measurer, but by a process of my own I can determine approximately the distance between the sending and the receiving points of a message."

He attached another, smaller machine to the wireless detector. In the face was a moving finger which swung over a dial marked off in miles from one upward. As Arnold adjusted the new detector, the hand began to move slowly. Woodward looked eagerly. It did not move far, but came to rest above the figure "2."

"Not so very far away, you see, Lieutenant," remarked Arnold, pointing at the dial face.

He seized his glass and hurried to the deck, levelling it at the shore, leaning far over the rail in his eagerness. As he swept the shore, he stopped suddenly. There was a house-roof among the trees with a wireless aerial fastened to the chimney, but not quite concealed by the dense foliage.

"Look," he cried to Woodward, with an exclamation of satisfaction, handing over the glass.

Woodward looked. "A secret wireless station, all right," he agreed, lowering the glass after a long look.

"We'd better get over there right away," planned Arnold, leading the way to the ladder over the side of the yacht and calling to the sailor who had managed the little motor-boat to follow him.

Quickly they skimmed across to the shore. "I think we'd better send to the Fort for some men," considered Arnold as they landed. "We may need reinforcements before we get through."

Woodward nodded and Arnold hastily wrote a note on a rather large scrap of paper which he happened to have in his pocket.

"Take this to Colonel Swift at Fort Dale," he directed the sailor. "And hurry!"

The sailor loped off, half on a run, as Arnold and Woodward left down the shore, proceeding carefully.

At top speed, Arnold's sailor made his way to Fort Dale and was directed by the sentry to Colonel Swift who was standing before the headquarters with several officers.

"A message from Lieutenant Woodward and Professor Arnold," he announced, approaching the commanding officer and handing him the note. Colonel Swift tore it open and read:

Have located radio aerial in the woods along shore. Please send squad of men with bearer.--ARNOLD.

"You just left them?" queried the Colonel.

"Yes sir," replied the sailor. "We came ashore in his boat. I don't know exactly where they went but I know the direction and we can catch up with them easily if we hurry, sir."

The colonel handed the note quickly to a cavalry officer beside him who read it, saluted at the orders that followed, turned and strode off, hastily stuffing the paper in his belt, as the sailor went, too.

Meanwhile, Del Mar's valet was leaving the bungalow and walking down the road on an errand for his master. Up the road he heard the clatter of hoofs. He stepped back off the road and from his covert he could see a squad of cavalry headed by the captain and a sailor cantering past.

The captain turned in the saddle to speak to the sailor, who rode like a horse marine, and as he did so, the turning of his body loosened a paper which he had stuffed quickly into his belt. It fell to the ground. In their hurry the troop, close behind, rode over it. But it did not escape the quick eye of Del Mar's valet.

They had scarcely disappeared around a bend in the road when he stepped out and pounced on the paper, reading it eagerly. Every line of his face showed fear as he turned and ran back to the bungalow.

"See what I found," he cried breathlessly bursting in on Del Mar who was seated at his desk, having returned from the harbor.

Del Mar read it with a scowl of fury. Then he seized his hat, and a short hunter's axe, and disappeared through the panel into the subterranean passage which took him by the shortest cut through the very hill to the shore.

Slowly Arnold and Woodward made their way along the shore, carefully searching for the spot where they had seen the house with the aerial. At last they came to a place where they could see the deserted house, far up on the side of a ravine above a river and a waterfalls. They dived into the thick underbrush for cover and went up the hill.

Some distance off from the house, they parted the bushes and gazed off across an open space at the ramshackle building. As they looked they could see a man hurry across from the opposite direction and into the house.

"As I live, I think that's Del Mar," muttered Arnold.

Woodward nodded, doubtfully, though.

In the house, Del Mar hurried to a wall where he found and pressed a concealed spring. A small cabinet in the plaster opened and he took out a little telephone which he rang and through which he spoke hastily. "Pull in the wires," he shouted. "We're discovered, I think."

Down in the wireless station in the cave, the operator at his instrument heard the signal of the telephone and quickly answered it. "All right, sir," he returned with a look of great excitement and anxiety. "Cut the wires and I'll pull them in."

Putting back the telephone, Del Mar ran to the window and looked out between the broken slats of the closed blinds. "Confound them!" he muttered angrily.

He could see Arnold and Woodward cautiously approaching. A moment later he stepped back and pulled a silk mask over his upper face, leaving only his eyes visible. Then he seized his hunter's axe and dashed up the stairs. Through the scuttle of the roof he came, making his way over to the chimney to which the wireless antennae were fastened.

Hastily he cut the wires which ran through the roof from the aerial. As he did so he saw them disappear through the roof. Below, in the cave, down in the ravine back of the falls, the operator was hastily hauling in the wire Del Mar had cut.

Viciously next, Del Mar fell upon the wooden aerial itself, chopping it right and left with powerful blows. He broke it off and threw it over the roof.

Below, Arnold and Woodward, taking advantage of every tree and shrub for concealment, had almost reached the house when the broken aerial fell with a bang almost on them. In surprise they dropped back of a tree and looked up. But from their position they could see nothing. Together they drew their guns and advanced more cautiously at the house.

Del Mar made his way back quickly over the roof, back through the scuttle and down the stairs again. Should he go out? He looked out of the window. Then he went to the door. An instant he paused thinking and listening, his axe raised, ready for a blow.

Arnold and Woodward, by this time, had reached the door which swung open on its rusty hinges. Woodward was about to go in when he felt a hand on his arm.

"Wait," cautioned Arnold. He took off his hat and jammed it on the end of a stick. Slowly he shoved the door open, then thrust the hat and stick just a fraction of a foot forward.

Del Mar, waiting, alert, saw the door open and a hat. He struck at it hard with the axe and merely the hat and stick fell to the floor.

"Now, come on," shouted Arnold to Woodward.

In the other hand, Del Mar held a chair. As Woodward dashed in with Arnold beside him, Del Mar shied the chair at their feet. Woodward fell over it in a heap and as he did so the delay was all that Del Mar had hoped to gain. Without a second's hesitation he dived through an open window, just as Arnold ran forward, avoiding Woodward and the chair. It was spectacular, but it worked. Arnold fired, but even that was not quick enough. He turned and with Woodward who had picked himself up in spite of his barked shins and they ran back through the door by which they had entered.

Recovering himself, Del Mar dashed for the woods just as Arnold and Woodward ran around the side of the house, still blazing away after him, as they followed, rapidly gaining.

Elaine changed her clothes quickly. Meanwhile she had ordered horses for both of us and a groom brought them around from the stables. It took me only a short time to jump into some dry things and I waited impatiently.

She was ready very soon, however, and we mounted and cantered off, again in the direction of the shore where she had seen the remarkable waterfall, of which she had told me.

We had not gone far when we heard sounds, as if an army were bearing down on us. "What's that?" I asked.

Elaine turned and looked. It was a squad of cavalry.

"Why, it's Lieutenant Woodward's friend, Captain Price," she exclaimed, waving to the captain at the head of the squad.

A moment later Captain Price pulled up and bowed. Quickly we told him of what Elaine had just discovered.

"That's strange," he said. "This man--" indicating the sailor-- "has just told me that Lieutenant Woodward and Professor Arnold are investigating a wireless outfit over near there. Perhaps there's some connection."

"May we join you?" she asked.

"By all means," he returned. "I was about to suggest it myself."

We fell in behind with the rest and were off again.

Under the direction of the sailor we came at last to the ravine where we looked about searchingly for some trace of Arnold and Woodward.

"What's that noise?" exclaimed one of the cavalrymen.

We could hear shots, above us.

"They may need us," cried Elaine, impatiently.

It was impossible to ride up the sheer height above.

"Dismount," ordered Captain Price.

His men jumped down and we followed him. Elaine struggled up, now helped by me, now helping me.

Further down the hill from the deserted house which we could see above us at the top was an underground passage which had been built to divert part of the water above the falls for power. Through it the water surged and over this boiling stream ran a board walk, the length of the tunnel.

Into this tunnel we could see that a masked man had made his way. As he did so, he turned for just a moment and fired a volley of shots.

Elaine screamed. There were Arnold and Woodward, his targets, coming on boldly, as yet unhit. They rushed in after him, in spite of his running fire, returning his shots and darting toward the tunnel entrance through which he still blazed back at them.

From our end of the ravine, we could see precisely what was going on. "Come--the other end of the tunnel," shouted Price, who had evidently been over the ground and knew it.

We made our way quickly to it and it seemed as if we had our man trapped, like a rat in a hole.

In the tunnel the man was firing back at his pursuers as he ran along the board walk for our end. He looked up just in time as he approached us. There he could see Price and his cavalry waiting, cutting off retreat. We were too many for him. He turned and took a step back. There were Arnold and Woodward with levelled guns peering in as though they could not see very clearly. In a moment their eyes would become accustomed as his to the darkness. What should he do? There was not a second to waste. He looked down at the planks beneath him and the black water slipping past on its way to the power station. It was a desperate chance. But it was all that was left. He dropped down and let himself without even a splash into the water.

Arnold and Woodward took a step into the darkness, scarcely knowing what to expect, their eyes a bit better accustomed to the dusk. But if they had been there an hour, in all probability they could not have seen what was at their very feet.

Del Mar had sunk and was swimming under water in the swift black current sweeping under them. As they entered, he passed out, nerved up to desperation.

Down the stream, just before it took its final plunge to the power wheel, Del Mar managed by a superhuman effort to reach out and grasp a wooden support of the flooring again and pull himself out of the stream. Smiling grimly to himself, he hurried up the bank.

"Some one's coming," whispered Price. "Get ready."

We levelled our guns. I was about to fire.

"Look out! Don't shoot!" warned a voice sharply. It was Elaine. Her keen eyes and quick perception had recognized Arnold, leading Woodward. We lowered our guns.

"Did you see a man, masked, come out here?" cried Woodward.

"No--he must have gone your way," we called.

"No, he couldn't."

Arnold was eagerly questioning the captain as Elaine and I approached. "Dropped into the water--risked almost certain death," he muttered, half turning and seeing us.

"I want to congratulate you on your nerve for going in there," began Elaine, advancing toward the professor.

Apparently he neither heard nor saw us, for he turned as soon as he had finished with Price and went into the cave as though he were too busy to pay any attention to anything else.

Elaine looked up at me, in blank astonishment.

"What an impolite man," she murmured, gazing at the figure all stooped over as it disappeared in the darkness of the tunnel.