impatience. "Load the mine onto the boat, Webb. Go out to the center of
the lake. Then when you have dropped it, give the usual signal."
"When everything is okay, I'll wave my lantern three times," Webb agreed.
The mine was trundled out and the shack became dark. However, Salt and
Penny did not dare come out of hiding until they heard Webb start the
motor of the boat.
"The coast is clear," the photographer then reported, peering out a crack
of the outer door. "Webb has gone, and the professor and Mr. Johnson are
walking up to the cabin."
From the beach, Penny and Salt watched the boat moving slowly across the
water. Presently the craft stopped, and the mine was heaved overboard.
The pair waited, but there was no signal from Webb. Nor did his boat move
away from the locality where the mine had been dropped.
"Why doesn't he wave the lantern?" Penny fretted.
"He's waiting deliberately, and for a purpose," Salt declared. "Why not
amble up the hill and watch the professor perform?"
"Not a bad idea," agreed Penny.
Walking rapidly, they arrived at the cabin quite breathless. As they
tapped lightly on the door, Professor Bettenridge appeared visibly
startled. He stiffened to alert, guarded attention, but relaxed slightly
as his wife admitted the pair.
"Oh, it's you two again," he said none too pleasantly. "You are just in
time to witness my final demonstration. We are waiting now for my
assistant's signal."
"It seems to take a long while," Mr. Johnson commented, glancing at his
watch.
"Webb may have had trouble getting the mine overboard," the professor
soothed. "Besides, he has to move out of the danger zone."
Penny and Salt looked at each other but said nothing. They were certain
that Webb had been in no haste to return to shore.
"What are you two smirking about?" the professor demanded irritably. "I
suppose you think my machine won't work?"
"I'll be surprised if it does," Salt agreed, unruffled.
Mrs. Bettenridge, who stood at the window, suddenly cried: "There is the
signal!"
Professor Bettenridge snapped on a switch and the ray machine began to
hum. He turned on another motor and lights began to glow. Then he struck
the crystal ball, producing a musical vibration.
Assuming a confident pose, he waited.
Nothing happened.
As the seconds ticked by and still there was no explosion, the professor
began to wilt. He gazed desperately at his wife who looked as dismayed as
he.
"My dear, something seems to be wrong. Are you sure you saw the signal?
Perhaps Webb has not yet dropped the mine."
"I saw the signal. The lantern was waved three times."
The professor made several adjustments on his machine, and again struck
the musical note. But there was no explosion. Enjoying his discomfiture,
Salt and Penny grinned from ear to ear.
"You did something to the machine!" the professor accused them furiously.
"You came here and tampered!"
"We've not been near this place tonight until a moment ago," Penny
retorted. "The truth is, you weren't able to explode Mr. Johnson's mine!"
"That's not so!" The professor's face now was red with anger. "Something
has gone wrong, but that doesn't prove my machine is a failure. We'll
have another test."
"I'm not sure that I shall be interested," Mr. Johnson said quietly.
"I've been thinking the matter over and there are so many hazards--"
"I'll make you an especially good offer," the professor declared,
flipping the canvas cover over his machine. "Furthermore, we will have
the test tonight. I guarantee to explode the mine before you leave here."
"But the mine I supplied is at the bottom of the lake and it failed to go
off," Mr. Johnson said.
"First, we will talk to Webb and learn exactly what happened," the
professor said, taking him by the arm. "I know there is a logical
explanation for the failure."
Glaring at Penny and Salt, he shooed everyone out of the cabin, locking
the door.
"My dear," he said to his wife, giving her a significant look, "take Mr.
Johnson to the house while I find Webb. I'll be with you in just a
minute."
The professor went hurriedly down the beach while Mrs. Bettenridge and
Mr. Johnson walked slowly toward the rooming house. Penny and Salt
remained beside the cabin until everyone was beyond hearing.
"Well, our trick worked," Salt chuckled, "but if we aren't careful, the
professor will pull off a successful test yet and ruin all our plans."
"He and Webb are certain to examine the mines and discover the one with
Mr. Johnson's initials still in the shack. Then they may convince Mr.
Johnson there was a mix-up, and go ahead with another test which will be
successful."
"We've got to do something," Salt muttered. "But what?"
"I know!" Penny exclaimed. "I'll telephone Dad and have him come here
right away with Major Bryan!"
"Good!" approved Salt. "I'll stay here and hold the fort while you
telephone. Tell your father to step on the gas, because we've got to move
fast to queer Professor Bettenridge's game."
CHAPTER
20
_A CROOK EXPOSED_
Eager to carry out Salt Sommers' bidding, Penny ran up the hill in search
of a telephone. She considered using the one at the house where Professor
and Mrs. Bettenridge roomed, but decided against it, fearing that the
conversation might be overheard or reported to them by the farm woman.
Hastening on, she saw a light farther down the road, and recalled having
noticed a house there. Five minutes later, completely winded, she pounded
on the door. A man in shirtsleeves, the evening newspaper in his hand,
answered her knock.
"Please, may I use your telephone?" Penny gasped.
"Why, sure," he agreed, stepping aside for her to enter. "Anything
wrong?"
Penny knew better than to mention what was happening at the lake. "I want
to telephone my father in Riverview," she explained.
"The phone is in the other room," the man said, switching on a light.
Placing the call, Penny waited impatiently for it to be put through. She
was uncertain whether her father would be at home. If she failed to reach
him, then the only other thing was to notify the sheriff.
"Here is your party. Go ahead, please," came the long distance operator's
voice. The next moment Penny heard her father's clear tones at the other
end of the line.
"Dad, I'm at Blue Hole Lake with Salt," she explained hurriedly. "Can you
drive here right away?"
"I suppose so," he answered, knowing from her voice that something
serious was wrong. "What's up?"
"We've learned plenty about Professor Bettenridge, Dad. Unless something
is done quickly, he may sell his fake machine to Mr. Johnson."
"But what can _I_ do about it?" the publisher asked.
"Can you get hold of the Major and bring him with you?" Penny pleaded.
"Professor Bettenridge may be the man he's after!"
"Maybe I can reach him!" Mr. Parker agreed. "If I have luck I'll be out
there within twenty or thirty minutes. I'll come as fast as I can."
Before hanging up the receiver, Penny gave her father detailed
instructions for reaching the lake and told him where to park. Leaving a
dollar bill to pay for the call, she then hastened back to find Salt.
The photographer was nowhere near the cabin and she was afraid to call
his name lest she be overheard by the Bettenridges.
As she stood in the shadow of the building, she heard voices from the
beach. Someone with a lighted lantern was coming up the trail, and soon
she distinguished two figures--Professor Bettenridge and Webb.
"That's the story you'll have to tell Johnson," she heard the professor
say. "Tell him that somehow you got the two mines mixed up as you were
loading them onto the boat and dumped one that was never meant to
explode."
"But he saw us load the mine."
"It was dark and he may not be sure. Anyway, the mine with Johnson's
initials is still in the shack. We'll show it to him."
"What bothers me is how did the mistake happen?" Webb muttered. "I know
the mine I loaded on the boat had Johnson's initials. It should have gone
off."
"Someone is onto our game, and tampered with the mines. It may have been
a trick of that newspaper pair."
"In that case, we're in a dangerous spot. We ought to clear out while the
clearing is good. If the authorities get onto what we're doing--"
"They won't--at least not tonight," the professor said confidently. "The
sheriff is as dumb as they come, and is convinced I am a genius second
only to Thomas Edison. We'll have to pull off a successful test tonight
with Johnson's mine, collect what we can, and clear out."
"Okay," Webb agreed, "but this is my last job. The game is too dangerous.
I served one stretch in the pen and I don't look forward to another."
"If we can explode Johnson's mine tonight, we'll collect the money and be
away from here as soon as we cash the check. Can you pull off the job
without any blunder?"
"Sure I can unless someone tampers with the mine! This time I'll make
sure they don't!"
"Okay," the professor agreed. "Now I want you to talk to Johnson. Put up
a good story, and get him to look at the mine that has his initials on
it. If he refuses, we're licked, but it's worth a final try."
"I'd like to find the guy who broke into the shack!" Webb muttered.
"We may have time for that later. Just now our most important job is to
convince Johnson we have something to sell."
The two men now were very close. Penny flattened herself against the
building wall, fearful of being seen. The light from their lantern
illuminated her for an instant, but the men were so absorbed in their
discussion, they failed to see her. Going on up the hillside path, they
vanished into the farmhouse.
What had become of Salt, Penny did not know. Thinking he might have gone
down to the lake, she walked rapidly in that direction. As she approached
the shack where the mines were stored, she heard a low whistle.
"Is that you, Salt?" she called softly.
He came from behind a clump of bushes to join her. Quickly they compared
notes. Salt had overheard no conversation, but he had watched Professor
Bettenridge and Webb as they reexamined the mines in the shack.
"They're onto our game, and it won't work twice," he said. "We've got to
delay the test, but how?"
"Maybe we could cut the boat loose!"
"A capital idea!" Salt approved, chuckling. "Penny, you really have a
brain!"
As they scurried over the stones to the water's edge, Penny suddenly
stopped short.
"Listen!" she commanded.
"I didn't hear anything," Salt said.
"An automobile stopped by the roadside. I'm sure of it. Maybe it's my
father!"
"He couldn't have reached here so soon."
"You don't know Dad," Penny chuckled. "He drives like the wind. It
certainly sounded like the engine of our car."
"Let's have a look before we cut the boat loose," Salt said, slipping a
knife back into his pocket.
"I'll go," Penny offered. "You wait here."
Before Salt could stop her, she darted away into the darkness. Crawling
under a barbed wire fence, she took a short cut to the road. Even before
she saw the car, she heard a voice which she recognized as her father's.
"Dad!" she called softly.
He was with another man whom Penny hoped was Major Bryan. As the two came
toward the fence, she saw that it was indeed the Army officer.
"Dad, how did you get here so quickly?" she greeted him. "Salt and I
didn't expect you for at least another twenty minutes."
"I was lucky enough to get hold of Major Bryan right away," Mr. Parker
answered, climbing over the fence. "Now I hope you haven't brought us on
a wild chase, Penny. What's up?"
"Come with me and I'll show you," she offered. "That's easier than
explaining everything."
Major Bryan, a well-built man of early middle age, asked Penny several
questions about Professor Bettenridge as the three walked hurriedly
toward the lake.
"From your description, he seems to be the man I'm after," he declared
grimly. "If he's the same person, his real name is Claude Arkwright and
he's wanted for impersonating an officer and on various other charges. He
pulled a big job in New York three months ago, then vanished."
Salt was waiting at the lake. "What's our move?" he asked, after relating
everything that had occurred that night. "Shall we cut the boat loose?"
"First, let me examine those mines," the major requested. "Can we get
into the shack?"
"I can pick the lock, but it takes time," Salt offered.
"We'll break it," the major decided. "Those men may return here at any
minute, so there's no time to lose."
The door was forced open and Penny was placed on guard to watch the
hillside for Webb or anyone in the professor's party.
There was no light in the shack, but both Mr. Parker and the major had
brought flashlights. Salt pointed out the mine which had been doctored by
Webb. Carefully, the Army officer examined it.
"I can't tell much by looking at it for the work has been cleverly
concealed," he admitted. "But from what you've told me, I am quite
certain how the mine is made to explode."
"How is it done?" Salt demanded.
"After the hole is made, a chemical--probably sodium--is inserted. Then
another substance which melts slowly in water is used to seal up the
opening."
"Then that explains why Webb delayed so long in giving the signal after
the mine had been dropped into the water!" Penny exclaimed from the
doorway. "He was waiting for the substance to melt!"
"Exactly," agreed the major. "If my theory is correct, only the action of
water is required to explode this mine. The professor's machine, of
course, has nothing whatsoever to do with it."
"Why don't we explode the mine now?" Penny suddenly proposed. "That would
put an end to the professor's little scheme."
"It might also prevent us from arresting him," the major said. He debated
a moment. Then he exclaimed: "It's worth trying! We'll load the mine on
the boat and dump 'er in the lake!"
The men would not permit Penny to help with the dangerous work. Carefully
they transported the mine to the boat. Salt was about to start the motor,
but the major stopped him.
"No, we don't want the sound of the engine to give us away," he said.
"We'll row out into the lake."
Penny was eager to accompany the men, but they would not hear of it. To
her disappointment, she was compelled to remain on the beach.
Sitting down on the sand, she nervously watched until the boat faded into
the black of the night. Presently, she heard a splash which told her that
the mine had been lowered overboard. Anxiously, she waited for the boat
to return.
"Why don't they come?" she thought, straining to hear the sound of oars.
"If the explosion should go off while they're still out there--"
Then she heard the boat coming and breathed in relief. Soon the craft
grated on sand, and the three men leaped out.
"Perhaps my theory is wrong," the major commented, as they all huddled
together, waiting. "The mine should have gone off by this time."
Several minutes elapsed and still nothing happened. And then, as the
group became convinced their plan had failed, there came a terrific
explosion which sent flame and water high above the lake's surface.
CHAPTER
21
_IN SEARCH OF WEBB_
"Beautiful! Beautiful!" chuckled the major as the flames began to die
away. "That proves our theory. No machine is required to set off the
mines--only the action of water."
"Professor Bettenridge must have heard the explosion!" Penny exclaimed,
fairly beside herself with excitement. "What will happen now?"
"If human nature runs true to form, he will soon come here to
investigate," the major predicted.
The four stepped back into the dense growth of trees to wait. Within five
minutes they observed two shadowy figures scurrying down the path toward
the shack where the mines were stored. As they came closer, Penny
recognized the professor and his wife.
"And someone is following them," she discerned. "It looks like Mr.
Johnson."
Professor Bettenridge and his wife now were near the trees. Their voices,
though low, carried to those in hiding.
"That stupid lout, Webb!" the professor muttered. "He has ruined
everything now by setting off the mine too soon."
"But how could it have been Webb?" his wife protested. "He was at the
farmhouse only five minutes ago. He wouldn't have had time."
"Then it was someone else--" Professor Bettenridge paused, and cast a
quick alert glance about the lake shore. He noted that the boat was tied,
but that the door of the shack was wide open.
"We've been exposed!" he muttered. "Our game is up, and we've got to get
away from here before the authorities arrest us."
"But what about Johnson?" his wife demanded, glancing over her shoulder
at the man who was following them down the hillside path.
"We can do nothing now. He had begun to catch on even before tonight, and
this explosion finishes everything. Don't even stop to pack your clothes.
We'll get our car and clear out."
"Webb?"
"He'll have to look out for himself. We're traveling alone and traveling
fast."
Those in hiding suddenly stepped forth from the trees, blocking the path.
Major Bryan moved directly in front of the professor, flashing a light
into his face.
"Good evening, Claude Arkwright," he said distinctly.
The professor was startled, but recovered poise quickly. "You are
mistaken," he said in a cold voice. "My name is Bettenridge."
"No doubt that is what you call yourself now. You are wanted by the
Federal government for impersonating an officer."
"Ridiculous!"
"May I see your draft card?" the major requested curtly.
"Sorry, I haven't it with me. It is in my room."
"Then we will go there."
Nettled, Professor Bettenridge could think of no further excuse. Glancing
significantly at his wife, he said: "My dear, will you go to the house
and get the card for our inquisitors?"
"We will all go," corrected the major. "Your wife may be wanted as your
accomplice in this latest secret ray machine fleece. We prefer that she
does not escape."
"You are very trusting," sneered the professor.
By this time, Mr. Johnson had reached the hillside. Puffing from having
hurried so fast, he gazed in bewilderment at the little group.
"What does this mean?" he inquired. "What caused the mine to explode?"
"It was set off by being dropped in the lake," explained the major.
"You mean the explosion was not touched off by Professor Bettenridge's
invention?"
"The machine had nothing whatsoever to do with it," Penny explained.
"Professor Bettenridge and his accomplice, Webb Nelson, have been
doctoring the mines with a powder and an outer shield which dissolves in
water. They hoped to sell the worthless machine to you before you
discovered the truth."
The information stunned Mr. Johnson, but recovering, he turned furiously
upon Professor Bettenridge.
"You cheap trickster!" he shouted. "I'll have you arrested for this!"
"Have you given the man any money?" Mr. Parker inquired.
"A thousand dollars for an option on the machine. The rest was to have
been paid tonight."
"You're lucky to get off so easily," Mr. Parker said. "It's possible too,
that we can get part of your deposit back."
"You can't hold me on any trumped-up charge," Professor Bettenridge said
angrily. "You have no warrant."
He started away, but was brought up short as he felt the major's revolver
pressing against his ribs.
"This will hold you, I think," said the Army man coolly. "Now lead the
way up the hill to the other cabin. I want to see your remarkable
invention."
With his wife clinging to his arm, the professor marched stiffly ahead of
the group. He unlocked the cabin door and all went inside.
Jerking off the canvas which covered the secret ray machine, Major Bryan
inspected it briefly.
"A worthless contraption!" he said contemptuously. "Utterly useless!"
"Where did you meet Webb Nelson?" Penny asked the professor. "And where
is he now?"
"You'll have to find him for yourself," sneered the professor. "If he has
the sense I think, he's probably miles away from here by now."
Determined that the man should not escape, Penny, Salt and Mr. Parker
started for the farmhouse, leaving the major and Mr. Johnson to question
the professor. As they rapped on the screen door, Mrs. Leonard came to
let them in.
"What is going on here tonight, may I ask?" she demanded irritably.
"People banging in and out of the house at all hours! Explosions! I
declare, I wish I never had rented a room to that crazy professor and his
wife!"
"Is Webb Nelson here?" Mr. Parker asked.
"The professor's helper? Why, no, right after the explosion he came,
gathered a bag of things from the professor's room, and went off down the
road."
"In a car?"
"He was afoot when he left here. Is anything wrong?"
"Considerable. Professor Bettenridge has just been exposed as an
impostor. Webb must have realized the jig was up when he heard the mine
go off."
"The professor an impostor!" Mrs. Leonard exclaimed. "Well, of all
things!"
"Which way did Webb go?" Mr. Parker asked.
"Down the road toward town when I last saw him."
"Maybe we can catch him!" Mr. Parker cried.
"If he didn't get a lift," Salt added.
All piled into the Parker car which had been left a short distance down
the road. But in the drive to Newhall, the man was not sighted. Nor did
inquiry in the town reveal anyone who had seen him.
"Undoubtedly he expected to be followed, and cut across the fields or
took a side road," Mr. Parker declared. "We'll have to depend upon the
authorities to pick him up now."
Stopping at the sheriff's office, warrants for the man's arrest were
sworn out, and the party then returned to Mrs. Leonard's. Professor
Bettenridge and his wife had been brought to the farmhouse by Major Bryan
who proposed to hold them there pending the arrival of federal
authorities from Riverview.
"There's one thing I want to know," Penny whispered to her father. "How
did Professor Bettenridge meet Webb? Perhaps he can explain the man's
connection with the _Snark_."
The question was put to the professor who replied briefly that he knew
nothing whatsoever about Webb Nelson.
"I met him only two weeks ago," he said. "He claimed to be an expert at
handling explosives, so I hired him."
No one believed the professor was telling the truth. However, it was
useless to question him further. Determined not to implicate himself, his
wife, or his helper, he spoke as seldom as possible.
"The man has a room here," Mr. Parker suggested. "Suppose we see what we
can find."
Mrs. Leonard led the way upstairs. The professor's room was locked, but
she opened it with a master key.
Two suitcases had been packed as if for a hasty departure and everything
was in disorder. All garments had been removed from the closets. The
scrap basket was filled with torn letters which Mr. Parker promptly
gathered together and placed in an envelope for future piecing together.
In one of the suitcases he found several newspaper clippings. One bore a
picture of the professor, but the name beneath it was Claude Arkwright,
and the story related that he was wanted in connection with a $10,000
hoax.
"Bettenridge is our man all right," the publisher declared. "We made no
mistake in holding him for the sheriff."
Penny had been searching the larger of the two suitcases which seemed to
contain only clothing. But as she reached the lower layer, she suddenly
gave a jubilant cry.
"Salt! Dad!" she exclaimed. "It's here! See what I've found!"
CHAPTER
22
_SALT'S MISSING CAMERA_
From the suitcase, Penny lifted Salt's camera. With a cry of pleasure, he
snatched it from her hand and eagerly examined it.
"Is it damaged in any way?" Penny asked.
"It doesn't seem to be. So the professor had it all the time just as we
thought!"
"And here are the plates I tossed into the car the night of the
explosion!" Penny added, burrowing deeper into the pile of clothing.
"They're probably ruined by now."
"Maybe not," said Salt, examining them. "The professor may have thought
they were unexposed plates and kept them for use later on."
"Anyway, it was crooked of him to try to keep the camera," Penny
declared. "Though I suppose such a small theft doesn't amount to much in
comparison to the trick he nearly played on Mr. Johnson."
"It matters to me," the photographer chuckled. "Am I glad to get this
camera back! The plates won't do us any good now they are outdated, but
I'll take them along anyhow. I'm curious to see if they would have shown
anything of significance."
"By all means develop them," urged Mr. Parker. "Anything else in the
suitcase?"