"There's no use chasing after 'em, Tom," observed Ned, as the two chums stood side by side outside the tank and gazed after the three men running off across the fields as fast as they could go. "They've got too much a start of us."
"I guess you're right, Ned," agreed Tom. "And we can't very well pursue them in the tank. She goes a bit faster than anything of her build, but a running man is more than a match for her in a short distance. If I had the Hawk here, there'd be a different story to tell."
"Well, seeing that you haven't," replied Ned, "suppose we let them go—which we'll have to, whether we want to or not—and see where they were hiding and if they left any traces behind."
"That's a good idea," returned Tom.
The place whence the men had emerged was a portion of the old factory farthest removed from the walls the tank had crunched its way through. Consequently, that part was the least damaged.
Tom and Ned came to what seemed to have been the office of the building when the factory was in operation. A door, from which most of the glass had been broken, hung on one hinge, and, pushing this open, the two chums found themselves in a room that bore evidences of having been the bookkeeper's department. There were the remains of cabinet files, and a broken letter press, while in one corner stood a safe.
"Maybe they were cracking that," said Ned.
"They were wasting their time if they were," observed Tom, "for the combination is broken—any one can open it," and he demonstrated this by swinging back one of the heavy doors.
A quantity of papers fell out, or what had been papers, for they were now torn and the edges charred, as if by some recent fire.
"They were burning these!" cried Ned. "You can smell the smoke yet. They came here to destroy some papers, and we surprised them!"
"I believe you're right," agreed Tom. "The ashes are still warm." And he tested them with his hand. "They wanted to destroy something, and when they found we were here they clapped the blazing stuff into the safe, thinking it would burn there.
"But the closing of the doors cut off the supply of air and the fire smouldered and went out. It burned enough so that it didn't leave us very much in the way of evidence, though," went on Tom ruefully, as he poked among the charred scraps.
"Maybe you can read some of 'em," suggested Ned.
"Part of the writing is in German," Tom said, as he looked over the mass. "I don't believe it would be worth while to try it. Still, I can save it. Here, I'll sweep the stuff into a box, and if we get a chance we can try to patch it together," and finding a broken box in what had been the factory office the young inventor managed to get into it the charred remains of the papers.
A further search failed to reveal anything that would be useful in the way of evidence to determine what object the three men could have had in hiding in the ruins, and Tom and Ned returned to the tank.
"What do you think about them, Tom?" asked Ned, as they were about to start off once more for the cross-country test.
"Well, it seems like a silly thing to say—as if I imagined my tank was all there was in this part of the country to make trouble—but I believe those men had some connection with Simpson and with that spy Schwen!"
"I agree with you!" exclaimed Ned. "And I think if we could get head or tail of those burned papers we'd find that there was some correspondence there between the man I saw up the tree and the workman you had arrested."
"Too bad we weren't a bit quicker," commented Tom. "They must have been in the factory when we charged it—probably came there to be in seclusion while they talked, plotted and planned. They must have been afraid to go out when the tank was walking through the walls."
"I guess that's it," agreed Ned. "Did you recognize any of the men, Tom?"
"No, I didn't see 'em as soon as you did, and when they were running they had their backs toward me. Was Simpson one?"
"I can't be sure. If one was, I guess he'll think we are keeping pretty closely after him, and he may give this part of the country a wide berth."
"I hope he does," returned Tom. "Do you know, Ned, I have an idea that these fellows—Schwen Simpson, and those back of them, including Blakeson—are trying to get hold of the secret of my tank for the Germans."
"I shouldn't be surprised. But you've got it finished now, haven't you? They can't get your patents away from you."
"No, it isn't that," said Tom. "There are certain secrets about the mechanism of the tank—the way I've increased the speed and power, the use of the spanners, and things like that—which would be useful for the Germans to know. I wouldn't want them to find out these secrets, and they could do that if they were in the tank a while, or had her in their possession."
"They couldn't do that, Tom—get possession of her—could they?"
"There's no telling. I'm going to be doubly on the watch. That fellow Blakeson is in the pay of the plotters, I believe. He has a big machine shop, and he might try to duplicate my tank if he knew how she was made inside."
"I see! That's why he was inquiring about a good machinist, I suppose, though he'll be mightily surprised when he learns it was you he was talking to the time your Hawk met with the little mishap."
"Yes, I guess maybe he will be a bit startled," agreed Tom. "But I haven't seen him around lately, and maybe he has given up."
"Don't trust to that!" warned Ned.
The tank was now progressing easily along over fields, hesitating not at small or big ditches, flow going uphill and now down, across a stretch of country thinly settled, where even fences were a rarity. When they came to wooden ones Tom had the workmen get out and take down the bars. Of course the tank could have crushed them like toothpicks, but Tom was mindful of the rights of farmers, and a broken fence might mean strayed cows, or the letting of cattle into a field of grain or corn, to the damage of both cattle and fodder.
"There's a barbed-wire fence," observed Ned, as he pointed to one off some distance across the field. "Why don't you try demolishing that?"
"Oh, it would be too easy! Besides, I don't want the bother of putting it up again. When I make the barbed-wire test I want some set up on heavy posts, and with many strands, as it is in Flanders. Even that won't stop the tank, but I'm anxious to see how she breaks up the wire and supports—just what sort of a breach she makes. But I have a different plan in mind now.
"I'm going to try to find a wooden building we can charge as we did the masonry factory. I want to smash up a barn, and I'll have to pick out an old one for choice, for in these war days we must conserve all we can, even old barns."
"What's the idea of using a barn, Tom?"
"Well, I want to test the tank under all sorts of conditions—the same conditions she'll meet with on the Western front. We've proved that a brick and stone factory is no obstacle."
"Then how could a flimsy wooden barn be?"
"Well, that's just it. I don't think that it will, but it may be that a barn when smashed will get tangled up in the endless steel belts, and clog them so they'll jam. That's the reason I want to try a wooden structure next."
"Do you know where to find one?"
"Yes; about a mile from here is one I've had my eyes on ever since I began constructing the tank. I don't know who owns it, but it's such a ramshackle affair that he can't object to having it knocked into kindling wood for him. If he does holler, I can pay him for the damage done. So now for a barn, Ned, unless you're getting tired and want to go back?"
"I should say not! Speaking of barns, I'm with you till the cows come home! Want any more machine gun work?"
"No, I guess not. This barn isn't particularly isolated, and the shooting might scare horses and cattle. We can smash things up without the guns."
The tank was going on smoothly when suddenly there was a lurch to one side, and the great machine quickly swung about in a circle.
"Hello!" cried Ned. "What's up now? Some new stunt?"
"Must be something wrong," answered the young inventor. "One of the belts has stopped working. That's why we're going in a circle."
He shut off the power and hastened down to the motor room. There he found his men gathered about one of the machines.
"What's wrong?" asked Tom quickly.
"Just a little accident," replied the head machinist. "One of the boys dropped his monkey wrench and it smashed some spark plugs. That caused a short circuit and the left hand motor went out of business. We'll have her fixed in a jiffy."
Tom looked relieved, and the machinist was as good as his word. In a few minutes the tank was moving forward again. It crossed out to the road, to the great astonishment of some farmers, and the fright of their horses, and then Tom once more swung her into the fields.
"There's the old barn I spoke of," he remarked to Ned. "It's almost as bad a ruin as the factory was. But we'll have a go at it."
"Going to smash it?" asked Ned.
"I'm going right through it!" Tom cried.