CHAPTER XX
QUEER MARKS
"What happened?" cried Jackson to Tom, as he leaned forward in his seatwhich was in the rear of the young inventor's.
"Don't know, exactly," was the answer, as Tom quickly shifted therudders to correct the slanting fall of his craft. "Sounded as thoughthere was a tremendous back-fire, or else the muffler blew up. Theengine is dead."
"Can you take her down safely?"
"Oh, yes, I guess so. She's a bit out of control, but the stabilizerwill keep her on a level keel. Good thing we installed it."
"You're right!" said Jackson.
Now they were falling earthward with great rapidity, but, thanks to thegyroscope stabilizer, the "side-slipping," than which there is nomotion more dreaded by an aviator, had nearly ceased. The craft wasvolplaning down as it ought, and Tom had it under as perfect control aswas possible under the circumstances.
"We'll get down all right if something else doesn't happen," he said toJackson, with grim humor.
"Well, let's hope that it won't," said the mechanic. "We're a gooddistance up yet."
They were, as a matter of fact, for the explosion, or whatever hadhappened to the craft, had occurred at a height of over two miles, andthey at once began falling. As yet Tom Swift was unaware of the exactnature of the accident or its cause. All he knew was that there hadbeen a big noise and that the engine had stopped working. He could notsee the silencer from where he sat, as it was constructed on theunderside of the motor, but he had an idea that the same sort of mishaphad occurred as on the occasion when the test machine had sailedthrough the roof of his workshop.
"But, luckily, this wasn't as bad," mused Tom. "Anyhow the motor is outof business."
And this was very evident. The young inventor had tried to start theapparatus after its stoppage by the explosion, but it had not respondedto his efforts, and then he had desisted, fearing to cause some furtherdamage, or, perhaps, endanger his own life and that of Jackson.
Down, down swept Silent Sam--doubly silent now, and Tom began lookingabout for a good place to make a landing. This was nothing new foreither him or his mechanician, and they accepted the outcome as amatter of course.
"Not a very lively place down there," remarked Jackson, as he lookedover the side of the cockpit.
"If we have to depend for help on any one down there, I guess we'll bea long time waiting," agreed Tom. They were about to land in a verylonely spot. It was one he had never before visited, though he knew itcould not be much more than twenty miles from his own home, as they hadnot flown much farther than that distance.
But, somehow or other, Tom had not visited this particular section, andknew nothing of it. He saw below him, as Jackson had seen, a lonelystretch of country--a big field, once a wood-lot, evidently, asscattered about were some stumps and some second growth trees. Therewere also a number of evergreens--Christmas trees Jackson called them.And this was the only open place for miles, the surrounding countrybeing a densely wooded one. There did not appear to be a house or otherbuilding in sight where they might seek help.
"But maybe we can make the repairs ourselves and keep on," the ladthought.
With practiced eye he picked out a smooth, grassy, level spot, in themidst of scattered evergreen trees, and there Tom Swift skillfullybrought his Air Scout to rest. With a gentle thud the rubber-tiredwheels struck the Earth, rolled along a little distance, and thencalled to a stop.
Hardly had the aeroplane ceased moving when Tom and his companionjumped out and began eagerly to examine the machinery to see the extentof damage.
"I thought so!" Tom exclaimed. "The silencer cracked under the strain.Those exhaust gases have more pressure that I believed possible. Iincreased the margin of safety on this muffler, too. But she'scracked, and I can't use the machine until I put on a new one. Goodthing I didn't ask for a government inspection until after this trialflight."
"That's so," agreed Jackson. "But can't you patch it up, or go onwithout a muffler, so we can get back home?"
"I'm afraid not," Tom answered. "You see I removed all the old exhaustpipe fittings when I put on my new silencer. Now if I took off myattachment there wouldn't be anything to carry off the dischargedgases, and they'd form a regular cloud about us. We couldn't stand itwithout gas masks, such as they use in the trenches, and we haven't anyof those with us."
"That's right," agreed Jackson. "Well, what do you want to do? Have mestay here and guard the machine while you go for help? Or shall I go?"
"I don't know why we both can't go," said Tom. "There is no use tryingto patch up this machine here. I'll have to send a truck after it, anddismantle it before I can get it home.
"As for either of us staying here on guard, I don't quite see the needof that. This looks like the jumping-off place to me. I don't believethere's a native within miles. I didn't see any houses as we came down,and I think Silent Sam will be perfectly safe here. No one can run offwith him, anyhow. He'd be as hard to start as an automobile with allfour wheels gone. Let's leave it here and both walk back."
"All right," agreed Jackson. "That suits me. Might as well leave ourtogs here, too. It will be easier walking without them," and he begantaking off the fur-lined suit, his cap, and his goggles, such as he andTom wore against the piercing cold of the upper regions.
"We can stuff them in the cockpit and leave them," went on themechanician, as he divested himself of his garments. As he stowed themaway in his seat he gave one more look at the broken muffler. As TomSwift said, his new silencer had literally blown up, a large piecehaving been torn from the gas chamber.
Something that Jackson saw caused him to utter an exclamation thatbrought Tom Swift to his side.
"What is it?" asked the young inventor.
"Look!" was the answer. "See! Just at the edge of that break! It'sbeen filed to make the metal thinner there than anywhere else. Youdidn't do that, did you?"
"I should say not!" cried Tom. "Why, to file there would mean to weakenthe whole structure."
"And that's exactly what's happened!" declared Jackson, as he gaveanother look. "Some one has filed this nearly through--leaving only athin metal skin, and when the gas pressure became too much it blew out.That's what happened!"
Tom Swift made a quick but thorough examination.
"You're right, Jackson!" he exclaimed. "That was filed deliberately tocause the accident. And it must have been done lately, for I carefullyinspected the silencer when I put it on, and it was in perfect order.There's been spy work here. Some one got into the hangar and filed thatcasing. Then the accumulated pressure of the gases did the rest."
"As sure as you're alive!" agreed Jackson. "Maybe that's what Gale didwhen he called."
"No," returned Tom, shaking his head, "he didn't get a chance to doanything like that. I watched him all the while. But perhaps this iswhat he referred to when he said he and his company would repudiate anyact of that spy with the gold tooth--Lydane, so Gale said his name was.Maybe that's what Lydane did."
"He was capable of it," agreed the mechanic, "but he couldn't have doneit that time you tripped him into the mud puddle. This silencer wasn'tbuilt then."
"No, you're right," assented Tom. "Then he must have been around since,doing some of his tricky work!"
"I don't see how that could have been," said Jackson slowly. "We'vekept a very careful watch, and your shop has been specially guarded."
"I know it has," said Tom. "There couldn't much get past Koku; but someone seems to have done it, or else how could that filing have beendone?"
Jackson shook his head. The problem was too much for him. He lookedcarefully at the exploded and broken silencer, and Tom, too, gave it acritical eye. There was no doubt but that it had been filed in severalplaces to weaken the structure of the metal.
"When did you last see that it was in perfect condition?" asked Jackson.
Tom named a certain date.
"That was just before Gale called," observed the mechanician. "Hemight have known of it."
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"I wish I'd known of it at the time," said Tom savagely. "He wouldn'thave gotten away as easily as he did. Well, there's no use standinghere talking about it. Let's get back to civilization and we'll sendback one of the trucks. Luckily I have another silencer I can put onfor the government test. This one will never be of any more use, thoughI may be able to save some of the valves and baffle plates."
Slowly they turned from the disabled aeroplane and started to look fora path that would lead them out of the lonely place. Tom as the firstto strike what seemed to be a cow path, or perhaps what had been a roadinto the wood lot in the early days.
As he tramped along it, followed by Jackson, the young inventorsuddenly stopped, as he came to a sandy place, and, stooping over,looked intently at some queer marks in the soil.
"What is it?" asked the mechanician.
"Looks like the marks of an automobile," said Tom slowly. "And I wasjust trying to remember where I'd seen marks like these before."