"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.

"h.e.l.lo!" 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

Chapter XVII

Veiled Threats

Like some prehistoric monster about to charge down upon another of its kind, Tank A, under the guidance of Tom Swift, reeled and b.u.mped her way over the uneven fields toward the old barn. Within the monster of steel and iron were raucous noises: the clang and clatter of the powerful gasolene motors; the rattle of the wheels and gears; all making so much noise that, in the engine room proper, not a word could be heard. Every order had to be given by signs, and Tom sent his electric signals from the conning tower in the same way. When running at full speed, it was almost impossible, even in the tower, which was some distance removed from the engine room, to hear voices unless the words were shouted.

"Why don't you go at it?" cried Ned to his "friend, who was peering through the observation slot in the tower."

"I'm getting in good position," Tom answered. "Or rather, the worst position I can find. I want to give the tank a good try-out, and I'm going at the barn on the a.s.sumption that this is in enemy country and that I can't pick and choose my advance.

"So I want to come up through that gully, and go at the barn from the long way. That will be the worst possible way I could do it, and if old Tank A stands the gaff I'll know she's a little bit nearer all right."

"I think she's all right as she is!" a.s.serted Ned in a yell, for just then Tom signaled for more speed, and the consequent increase in the rattling and banging noises made it correspondingly difficult for talk to be heard.

The big machine now tipped into the little gully spoken of by Tom. This meant a dip downward, and then a climb out again and an attack on the barn going uphill and at an angle. But, as the young inventor had said, it would make a severe test and that was what he wanted to give his ponderous machine.

Ned grasped one of the safety rings, as, with a reel to one side, almost as if it were going to capsize, the tank rumbled on. Tom cast a half-amused smile at his chum, and then threw over the guiding lever.

The tank rolled down into the gully. It was rough and filled with stones and boulders, some of considerable size. But Tank A made less than nothing even of the largest rocks. Some she crushed beneath her steel belts. Others she simply "walked" over, smashing them down into the soil.

Now the big machine reached the bottom of the gulch and started up the sides, which, though not as steep as the trench in which she had capsized, still were not easy going.

"Now for it!" cried Tom, as he signaled for full speed.

Up climbed the tank. Now she was halfway. A moment later, and she was at the top, and then a forward careening motion told that she had pa.s.sed over the summit and was ready for the attack proper.

Ned gave a quick glance through the slot nearest him. He had a glimpse of the barn, and then he saw something else. This was the sight of a man running away from the dilapidated structure--a man who glanced toward the tank with a face that showed great fright.

"Stop! Stop!" yelled Ned. "There may be folks in there, Tom! I just saw a man run out!"

"All right!" Tom cried, though Ned could hardly hear him. "Tell me when we get on the other side! We're going through now!"

"But," shouted Ned, "don't you understand? I saw a man come out of there! Maybe there's more inside! Wait, Tom, and--"

But it was too late. The next instant there was a smashing, grinding, splintering crash, a noise as of a thunder-clap, and Tank A fairly ate her way through the old barn as a rat might eat his way into a soft cheese, only infinitely more quickly.

On and on and through and through went the tank, knocking beams, boards, rafters and timbers. .h.i.ther and thither. Minding not at all the weight of great beams on her back, caring nothing for those that got in the way of her steel belts, heeding not the wall of wood that reared itself before her in a barrier of splinters and slivers, Tank A went on and on until finally, with another grinding crash, as she smashed her way through the farthermost wall, the great engine of war emerged on the other side and came panting into the field, dragging with her a part of the structure clinging to her steel sides.

"Well," cried Tom, with a laugh, as he signaled for the power to be shut off, thereby making it possible for ordinary conversation to be heard, "I guess we didn't do a thing to that barn!"

"Not much left of it, for a fact, Tom," agreed Ned, as he looked through the after observation slots at the ruin in the rear. "But didn't you hear what I was saying?"