Like some prehistoric monster about to charge down upon another of its kind, Tank A, under the guidance of Tom Swift, reeled and bumped 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 assumption 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!" asserted 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 half-way. A moment later, and she was at the top, and then a forward careening motion told that she had passed 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 hither 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?"

"I heard you yelling something to me, but I was too anxious to go at it as fast as I could. I didn't want to stop then. What was the trouble?"

"That's what I'm afraid of, Tom--there may be trouble. Just before you tackled the barn for a knockdown, instead of a touchdown, as we might say, I saw a man running out of it. I thought if there was one there, perhaps there might be more. That's why I yelled to you."

"A man running from the old barn!" cried Tom. "Whew!" he whistled. "I wish I had seen him. But, Ned, if one ran out of harm's way, any others who might possibly be in there would do the same thing, wouldn't they?"

"I hope so," returned Ned doubtfully.

"Great Scott!" cried Tom, as the possibility was borne home to him. "If anything has happened--"

He sprang for the door of the tower and threw over the catch, springing out, followed by Ned. From the engine room of the armored tank the men came, smiles of gratification on their faces.

"We certainly busted her wide open, Mr. Swift!" called the chief mechanician.

"Yes," assented the young inventor; but there was not as much gratification in his voice as there should have been. "There isn't much of a barn left, but Ned thinks he saw some one run out, and if there was one man there may have been more. We'd better have a look around, I guess."

The engineering force exchanged glances. Then Hank Baldwin, who was in charge of the motors, said:

"Well, if there was anybody in that barn when we chewed her up I wouldn't give much for his hide, German or not."

"Let us hope no one was in there," murmured Tom.

They turned to go back to the demolished structure, fear and worry in their hearts. No more complete ruin could be imagined. If a cyclone had swept over the barn it could not have more certainly leveled it. And, not only was it leveled, crushed down in the center by the great weight of the tank, but the boards and beams were broken into small pieces. Parts of them clung in long, grotesque splinters to the endless steel belts.

"I don't see how we're going to find anybody if he's in there," remarked Hank.

"We'll have to," insisted Tom. "We can look about and call. If any one is there he may have been off to one side or to one end, and be protected under the debris. I wish I had heard you call, Ned."

"I wish you had, Tom. I yelled for all I was worth."

"I know you did. I was too eager to go on, and, at the same time, I really couldn't stop well on that hill. I had to keep on going. Well, now to learn the worst!"

They walked back toward the demolished barn. But they had not reached it when from around the corner swung a big automobile. In it were several men, but chief, in vision at least, among them, was a burly farmer who had a long, old- fashioned gun in his hands. On his bearded face was a grim look as he leaped out before the machine had fairly stopped, and called:

"Hold on, there! I guess you've done damage enough! Now you can pay for it or take the consequences!" And he motioned to Tom, Ned, and the others to halt.