Suddenly there was a noise at the end of the shed where the door to the offices lay. Two figures burst through from the gla.s.s doors and charged down the lanes between the lathes and cranes. Ned Newton led, Rad Sampson, his face a mouse-gray with fear, followed.

"Ma.s.sa Tom! Ma.s.sa Tom!" shouted the colored man. "Look out fo' de bomb!

Look out fo' de bomb!"

The foreman sprang toward the high door of the locomotive where Tom stood, staring out. The young inventor, quick as his mind usually functioned, did not understand at all what Eradicate meant.

"There's something wrong in there, Mr. Tom!" shouted the foreman. "Come down, sir, and let me get up there and see what it is."

But Mr. Barton Swift grasped the meaning of what was going on more quickly than anybody else. Tom's father, Tom frequently said, had spent so many years investigating chemical and mechanical mysteries that he saw more clearly and more exactly into and through most problems than other people.

His raised voice now cut through the rumble of machinery and all the other noises of the shop. Even Rad Sampson's delirious cry was dwarfed by Mr. Swift's sharp tone:

"Tom! The ticking of that watch! That means danger!"

The declaration seemed to rip away a curtain from Tom's thoughts.

Perhaps Rad's cry about "de bomb" aided the young inventor to understand the peril that threatened.

The faint ticking sound that had begun to annoy him during the past few minutes betrayed the nature of the threatening peril. Tom swung back from the open doorway of the locomotive cab, reached in to the s.p.a.ce between the motors, and seized the bundle of overall stuff that he had previously spied.

He knew instantly that the rapid ticking came from that bundle. It could be nothing but a time bomb. He had heard of such things and, indeed, had seen one before, an infernal machine which, set like an alarm clock, would go off at a certain time. That indicated time might be an hour hence, or might be within a few seconds! Ned Newton, almost at the spot, shouted to Tom when the latter reappeared with the bundle in his hands:

"Get down out of that, Tom Swift! Quick! For your life!"

But Tom was cool enough now. He saw his father's white, strained face at one side and the young inventor could even smile at him. Behind the foreman was set a barrel of water in which tools were cooled and tempered.

"Stoop, McAvoy!" Tom shouted, and tossed the bundle from him.

Had the infernal machine exploded in midair Tom would not have been surprised. But McAvoy dodged, Rad clapped his hands over his ears, and, even Ned Newton halted like a bird-dog at point.

The bundle splashed into the barrel of water. It sank to the bottom.

There was no explosion. When a few seconds had pa.s.sed the group of excited men began to relax. The barrel was carried carefully to a neighboring field.

"Fo' de lawsy sake!" gasped Rad, and got a full breath again.

"That was touch and go, sure enough," muttered Ned Newton.

"Those overalls sure went to the wash, Boss," declared the foreman.

"What was in 'em? And who put 'em in the cab up there?"

But Tom dropped down the ladder and went to his father. Their hands sought each other and gripped, hard.

"Better not tell Mary about this," whispered Tom. "She's worried enough as it is."

"Right, Tom," agreed the old inventor. "From this time on we cannot be too careful. If there proves to be an infernal machine in that package we may be sure that we are dealing with desperate men. We've got to keep our eyes open."

"Wide open," added Ned.

"I'll say we have," said Tom.

Chapter XII

The Try-Out Day Arrives

It did not need Ned Newton's story of what he had overheard at the bank to prove that an attempt had been made to blow to pieces Tom Swift's electric locomotive before even it had been tested.

An examination of the water-soaked package in the open yard of the shops of the Swift Construction Company, proved that there was enough explosive in the bomb to blow the shed itself to pieces. But the stopping of the clockwork attachment of course made the bomb harmless.

"The main thing to be explained," Tom said, when he and his father and Ned discussed the particulars of the affair, "is not who did it, or what it was done for. Those are comparatively easy questions to answer."

"Yes," agreed Ned. "O'Malley did it, or caused it to be done; and it was an attempt to balk Mr. Bartholomew and the H, & P. A. rather than a direct attack upon the Swift Construction Company."

"I am afraid, however," remarked Mr. Swift, "that Tom has aroused the personal antagonism of this spy from the West. We must not overlook that."

"I don't," replied the young inventor. "O'Malley has it in for me. No doubt of that. But he could not be sure that I would be hurt by the explosion he arranged for."

"True," said his father.

"The attempt was against my invention. And O'Malley was doubtless urged to destroy the locomotive that I am building because my success will aid Mr. Bartholomew and his railroad."

"Quite agreed," said Ned. "But--"

"But the important question," interrupted Tom, "is this: How did the bomb get into the interior of the electric locomotive? That is the first and most important problem. Its having been done once warns us that it can be done again until our system of guarding the works is changed."

"We have five watchmen on the job at night, and the gates are never opened in the daytime to anybody for any purpose without a pa.s.s,"

declared Ned. "I don't see how that fellow got in here with the time bomb."

"Exactly. It shows that there is a fault in our system somewhere," said Tom grimly. "We cannot surround the place at night with an armed guard.

It would cost too much. Even Koku cannot be everywhere. And I have reason to know that he was wandering about the stockade last night as usual."

"The fellow was pretty sharp to slip by," Ned observed.

"The stockade is no mean barrier, especially with the rows of barbed wire at the top," said Mr. Swift.

"Barbed wire! That's it!" exclaimed Tom. It was just here that Mr.

Damon's idea for guarding his prize buff Orpingtons came into play in Tom's scheme of things. "Barbed wire doesn't seem to keep out spies,"

he added slowly. "But believe me, something else will!"

For Tom to think of a thing was to start action without delay.

Immediately he called a gang from the shops and set them to work stringing copper wire along the top of the stockade.

He was sure that the man who had set the time bomb in place had got into the enclosure over the fence. If he tried the same trick again he was very apt to have the surprise of his life!

Each night when the shops closed and the watchmen went on duty, a current of electricity was turned into those copper wires entwined with the barbed wire entanglement at the top of the stockade that would certainly double up any marauder who sought to get over the top.

However, no further attempt was made against Tom's peace of mind and against his invention during the immediate weeks that followed. The young inventor was so closely engaged in his work that he scarcely left the house or the confines of the shops. Even Mary Nestor saw very little of him.