Tom cast a hasty glance over the mechanism of the machine before he started to cross the stream by the additional aid of the grippers, or spanners, as he sometimes called this latest device.
Along each side, in a row of sockets, were two long girders of steel, latticed like the main supports of a bridge. They were of peculiar triangular construction, designed to support heavy weights, and each end was broadly flanged to prevent its sinking too deeply into the earth on either side of a gully or a stream.
The grippers also had a sort of clawlike arrangement on either end, working on the principle of an "orange-peel" shovel, and these claws were designed to grip the earth to prevent slipping.
The spanners would be pulled out from their sockets on the side of the tank by means of steel cables, which were operated from within. They would be run out across the gap and fastened in place. The tank was designed to travel along them to the other side of the gap, and, once there, to pick up the girders, slip them back into place on the sides, and the engine of war would travel on.
"You are mightily excited, Tom.
"I admit it, Ned. You see, I have not tried the grippers out except on a small model. They worked there, but whether they will work in practice remains to be seen. Of course, at this stage, I'm willing to stake my all on the results, but there is always a half-question until the final try-out under practical conditions."
"Well, we'll soon see," said one of the workmen. "Are you ready, Mr. Swift?"
"All ready," answered Tom.
Tank A, as she was officially known, had come to a stop, as has been said, on the very edge of Tinkle Creek. The banks were fairly solid here, and descended precipitously to the water ten feet below. The shores were about twenty feet apart.
"Suppose the spanners break when you're halfway over, Tom?" asked his chum.
"I don't like to suppose anything of the sort. But if they do, we're going down!"
"Can you get up again?"
"That remains to be seen," was the non-committal reply. "Well, here goes, anyhow!"
Going up into the observation tower, which was only slightly raised above the roof of the highest part of the tank, Tom gave the signal for the motors to start. There was a trembling throughout the whole of the vast structure. Tom threw back a lever and Ned, peering from a side observation slot, beheld a strange sight.
Like the main arm of some great steam shovel, two long, latticed girders of steel shot out from the sides of the tank. They gave a half turn, as they were pulled forward by the steel ropes, so that they lay with their broader surfaces uppermost.
Straight across the stream they were pulled, their clawlike ends coming to a rest on the opposite bank. Then they were tightened into place by a backward pull on the operating cables, and Tom, with a sigh of relief, announced:
"Well, so far so good!"
"Do we go over now?" inquired Ned.
"Over the top—yes, I hope," answered Tom, with a laugh. "How about you down there?" he called to the engine room through a telephone which could only be used when the machinery was not in action, there being too much noise to permit the use of any but visual signals after that.
"All right," came back the answer. "We're ready when you are."
"Then here we go!" said Tom. "Hold fast, Ned! Of course there's no real telling what will happen, though I believe we'll come out of it alive."
"Cheerful prospect," murmured Ned.
The grippers were now in place. It only remained for the tank to propel herself over them, pick them up on the other side of Tinkle Creek, and proceed on her course.
Tom Swift hesitated a moment, one hand on the starting lever and the other on the steering wheel. Then, with a glance at Ned, half whimsical and half resolute, Tom started Tank A on what might prove to be her last journey.
Slowly the ponderous caterpillar belts moved around on the sprocket wheels. They ground with a clash of steel on the surface of the spanners. So long was the tank that the forward end, or the "nose," was halfway across the stream before the bottom part of the endless belts gripped the latticed bridge.
"If we fall, we'll span the creek, not fall into it," murmured Ned, as he looked from the observation slot.
"That's what I counted on," Tom said. "We'll get out, even if we do fall."
But Tank A was not destined to fall. In another moment her entire weight rested on the novel and transportable bridge Tom Swift had evolved. Then, as the gripping ends of the girders sank farther into the soil, the tank went on her way.
Slowly, at half speed, she crawled over the steel beams, making progress over the creek and as safely above the water as though on a regularly constructed bridge.
On and on she went. Now her entire weight was over the middle of the temporary structures. If they were going to give way at all, it would be at this point. But they did not give. The latticed and triangular steel, than which there is no stronger form of construction, held up the immense weight of Tank A, and on this novel bridge she propelled herself across Tinkle Creek.
"Well, the worst is over," remarked Ned, as he saw the nose of the tank project beyond the farthermost bank.
"Yes, even if they collapse now nothing much can happen," Tom answered. "It won't be any worse than wallowing down into a trench and out again. But I think the spanners will hold."
And hold they did! They held, giving way not a fraction of an inch, until the tank was safely across, and then, after a little delay, due to a jamming of one of the recovery cables, the spanners were picked up, slid into the receiving sockets, and the great war engine was ready to proceed again.
"Hurrah!" cried Ned. "She did it, Tom, old man!" and he clapped his chum resoundingly on the back.
"She certainly did!" was the answer. "But you needn't knock me apart telling me that. Go easy!"
"Bless my apple pie!" cried Mr. Damon, who was as much pleased as either of the boys, "this is what I call great!"
"Yes, she did all that I could have hoped for," said Tom. "Now for the next test."
"Bless my collar button! is there another?"
"Just down into a trench and out again." Tom said. "This is comparatively simple. It's only what she'll have to do every day in Flanders."
The tank waddled on. A duck's sidewise walk is about the only kind of motion that can be compared to it. The going was easier now, for it was across a big field, and Tom told his friends that at the other end was a deep, steep and rocky ravine in which he had decided to give the tank another test.
"We'll imagine that ravine is a trench," he said, "and that we've got to get on the other side of it. Of course, we won't be under fire, as the tanks will be at the front, but aside from that the test will be just as severe."
A little later Tank A brought her occupants to the edge of the "trench."
"Now, little girl," cried Tom exultingly, patting the rough steel side of his tank, "show them what you can do!"
"Bless my plum pudding!" cried Mr. Damon, "are you really going down there, Tom Swift?"
"I am," answered the young inventor. "It won't be dangerous. We'll crawl down and crawl out. Hold fast!"
He steered the machine straight for the edge of the ravine, and as the nose slipped over and the broad steel belts bit into the earth the tank tilted downward at a sickening angle.
She appeared to be making the descent safely, when there was a sudden change. The earth seemed to slip out from under the broad caterpillar belts, and then the tank moved more rapidly.
"Tom, we're turning over!" shouted Ned. "We're capsizing!"
Only too true were the words Ned Newton shouted to his chum. Tank A was really capsizing. She had advanced to the edge of the gully and started down it, moving slowly on the caterpillar bands of steel. Then had come a sudden lurch, caused, as they learned afterward, by the slipping off of a great quantity of shale from an underlying shelf of rock.
This made unstable footing for the tank. One side sank lower than the other, and before Tom could neutralize this by speeding up one motor and slowing down the other the tank slowly turned over on its side.
"But she isn't going to stop here!" cried Ned, as he found himself thrown about like a pill in a box. "We're going all the way over!"
"Let her go over!" cried Tom, not that he could stop the tank now. "It won't hurt her. She's built for just this sort of thing!"
And over Tank A did go. Over and over she rolled, sidewise, tumbling and sliding down the shale sides of the great gully.
"Hold fast! Grab the rings!" cried Tom to his two companions in the tower with him. "That's what they're for!"
Ned and Mr. Damon understood. In fact, the latter had already done as Tom suggested. The young inventor had read that the British tanks frequently turned turtle, and he had this in mind when he made provision in his own for the safety of passengers and crew.
As soon as he felt the tank careening, Tom had pressed the signal ordering the motors stopped, and now only the force of gravity was operating. But that was sufficient to carry the big machine to the bottom of the gulch, whither she slid with a great cloud of sand, shale and dust.
"Bless my—bless my—" Mr. Damon was murmuring, but he was so flopped about, tossed from one side to the other, and it took so much of his attention and strength to hold on to the safety ring, that he could not properly give vent; to one of his favorite expressions.
But there comes an end to all things, even to the descent of a tank, and Tom's big machine soon stopped rolling, sliding, and turning improvised somersaults, and rested in a pile of soft shale at the bottom of the gully. And the tank was resting on her back!
"We've turned turtle!" cried Ned, as he noted that he was standing on what, before, had been the ceiling of the observation tower. But as everything was of steel, and as there was no movable furniture, no great harm was done. In fact, one could as well walk on the ceiling of the tank as on the floor.
"But how are you going to get her right side up?" asked Mr. Damon.
"Oh, turning upside down is only one of the stunts of the game. I can right her," was the answer.
"How?" asked Ned.
"Well, she'll right herself if there's ground enough for the steel belts to get a grip on.
"But can the motors work upside down?"
"They surely can!" responded Tom. "I made 'em that way on purpose. The gasolene feeds by air pressure, and that works standing on its head, as well as any other way. It's going to be a bit awkward for the men to operate the controls, but we won't be this way long. Before I start to right her, though, I want to make sure nothing is broken."
Tom signaled to the engine room, and, as the power was off and the speaking tube could be used, he called through it:
"How are you down there?"
"Right-o!" came back the answer from a little Englishman Tom had hired because he knew something about the British tanks. "'Twas a bit of nastiness for a while, but it won't take us long to get up ag'in."
"That's good!" commented Tom. "I'll come down and have a look at you."
It was no easy matter, with the tank capsized, to get to the main engine room, but Tom Swift managed it. To his delight, aside from a small break in one of the minor machines, which would not interfere with the operation or motive force of the monster war engine, everything was in good shape. There was no leak from the gasolene tanks, which was one of the contingencies Tom feared, and, as he had said, the motors would work upside down as well as right side up, a fact he had proved more than once in his Hawk.
"Well, we'll make a start," he told his chief engineer. "Stand by when I give the signal, and we'll try to crawl out of this right side up."
"How are you going to do it?" asked Ned, as his chum crawled back into the observation tower.
"Well, I'm going to run her part way up the very steepest part of the ravine I can find—the side of a house would do as well if it could stand the strain. I'm going to stand the tank right up on her nose, so to speak, and tip her over so she'll come right again."
Slowly the tank started off, while Tom and his friends in the observation tower anxiously awaited the result of the novel progress. Ned and Mr. Damon clung to the safety rings. Tom put his arm through one and hung on grimly, while he used both hands on the steering apparatus and the controls.
Of course the trailer wheels were useless in a case of this kind, and the tank had to be guided by the two belts run at varying speeds.
"Here we go!" cried Tom, and the tank started. It was a queer sensation to be moving upside down, but it did not last very long. Tom steered the tank straight at the opposite wall of the ravine, where it rose steeply. One of the broad belts ran up on that side. The other was revolved in the opposite direction. Up and up, at a sickening angle, went Tank A.
Slowly the tank careened, turning completely over on her longer axis, until, as Tom shut off the power, he and his friends once more found themselves standing where they belonged—on the floor of the observation tower.
"Right side up with care!" quoted Ned, with a laugh. "Well, that was some stunt—believe me!"
"Bless my corn plaster, I should say so!" cried Mr. Damon.
"Well, I'm glad it happened," commented Tom. "It showed what she can do when she's put to it. Now we'll get out of this ditch."
Slowly the tank lumbered along, proper side up now, the men in the motor room reporting that everything was all right, and that with the exception of a slight unimportant break, no damage had been done.
Straight for the opposite steep side of the gully Tom directed his strange craft, and at a point where the wall of the gulch gave a good footing for the steel belts, Tank A pulled herself out and up to level ground.
"Well, I'm glad that's over," remarked Ned, with a sigh of relief, as the tank waddled along a straight stretch. "And to think of having to do that same thing under heavy fire!"
"That's part of the game," remarked Tom. "And don't forget that we can fire, too—or we'll be able to when I get the guns in place. They'll help to balance the machine better, too, and render her less likely to overturn."
Tom considered the test a satisfactory one and, a little later, guided his tank back to the shop, where men were set to work repairing the little damage done and making some adjustments.
"What's next on the program?" asked Ned of his chum one day about a week later. "Any more tests in view?"
"Yes," answered Tom. "I've got the machine guns in place now. We are going to try them out and also endeavor to demolish a building and some barbed wire. Like to come along?"
"I would!" cried Ned.
A little later the tank was making her way over a field. Tom pointed toward a deserted factory, which had long been partly in ruins, but some of the walls of which still stood.
"I'm going to bombard that," he announced, and then try to batter it down and roll over it like a Juggernaut. Are you game?"
"Do your worst!" laughed Ned. "Let me man one of the machine guns!"
"All right," agreed Tom. "Concentrate your fire. Make believe you're going against the Germans!"
Slowly, but with resistless energy, the tank approached the ruined factory.
"Are you sure there's no one in it, Tom?"
"Sure! Blaze away!"
Ned Newton sighted his machine gun. Tom had showed him how to work it, and indeed the young bank clerk had had some practice with a weapon like this, erected on a stationary tripod. But this was the first time Ned had attempted to fire from the tank while it was moving, and he found it an altogether different matter.
"Say, it sure is hard to aim where you want to!" he shouted across to Tom, it being necessary, even in the conning tower, where this one gun was mounted, to speak loudly to make one's self heard above the hum, the roar and rattle of the machinery in the interior of Tank A, and below and to the rear of the two young men.
"Well, that's part of the game," Tom answered. "I'm sending her along over as smooth ground as I can pick out, but it's rough at best. Still this is nothing to what you'll get in Flanders."
"If I get there!" exclaimed Ned grimly. "Well, here goes!" and once more he tried to aim the machine gun at the middle of the brick wall of the ruined factory.
A moment later there was a rattle and a roar as the quick-firing mechanism started, and a veritable hail of bullets swept out at the masonry. Tom and Ned could see where they struck, knocking off bits of stone, brick and cement.
"Sweep it, Ned! Sweep it!" cried Tom. "Imagine a crowd of Germans are charging out at you, and sweep 'em out of the way!"
Obeying this command, the young man moved the barrel of the machine gun from side to side and slightly up and down. The effect was at once apparent. The wall showed spatter-marks of the bullets over a wider area, and had a body of Teutons been before the factory, or even inside it, many of them would have been accounted for, since there were several holes in the wall through which Ned's bullets sped, carrying potential death with them.
"That's better!" shouted Tom. "That'll do the business! Now I'm going to open her up, Ned!"
"Open her up?" cried the young bank clerk, as he ceased firing.
"Yes; crack the wall of that factory as I would a nut! Watch me take it on high—that is, if the old tank doesn't go back on me!"
"You mean you're going to ride right over that building, Tom?"
"I mean I'm going to try! If Tank A does as I expect her to, she'll butt into that wall, crush it down by force and weight, and then waddle over the ruins. Watch!"
Tom sent some signals to the motor room. At once there was noticed an increase in the vibrations of the ponderous machine.
"They're giving her more speed," said Tom. "And I guess we'll need it."
Straight for the old factory went Tank A. In spite of its ruined condition, some of the walls were still firm, and seemed to offer a big obstacle to even so powerful an engine of war as this monstrous tank.
"Get ready now, Ned," Tom advised. "And when I crack her open for you cut loose with the machine gun again. This gun is supposed to fire straight ahead and a little to either side. There are other guns at left and right, amidships, as I might say, and there's also one in the stern, to take care of any attack from that direction.
"The men in charge of them will fire at the same time you do, and it will be as near like a real attack as we can make it—with the exception of not being fired back at. And I wouldn't mind if such were the case, for I don't believe anything, outside of heavy artillery, will have any effect on this tank."
Tank A was now almost at her maximum speed as she approached closer to the deserted factory. Ned and Tom, in the conning tower, saw the largest of the remaining walls looming before them. Straight at it rushed the ponderous machine, and the next moment there came a shock which almost threw Ned away from his gun and back against the steel wall behind him.
"Hold fast!" cried Tom. "Here we go! Fire. Ned! Fire!"
There was a crash as the blunt nose of the great war tank hit the wall and crumpled it up.
A great hole was made in the masonry, and what was not crushed under the caterpillar belts of the tank fell in a shower of bricks, stone and cement on top of the machine.
Like a great hail storm the broken masonry pelted the steel sides and top of the tank. But she felt them no more than does an alligator the attacks of a colony of ants. Right on through the dust the tank crushed her way. Added to the noise of the falling walls was that of the machine guns, which were barking away like a kennel of angry hounds eager to be unleashed at the quarry.
Ned kept his gun going until the heat of it warned him to stop and let the barrel cool, or he knew he would jam some of the mechanism. The other guns were firing, too, and the bullets sent up little spatter points of dust as they hit.
"Great jumping hoptoads!" yelled Ned above the riot of racket outside and inside. "Feel her go, Tom!"
"Yes, she's just chewing it up, all right!" cried the young inventor, his eyes shining with delight.
The tank had actually burst her way through the solid wall of the old factory, permission to complete the demolition of which Tom had secured from the owners. Then the great machine kept right on. She fairly "walked" over the piles of masonry, dipped down into what had been a basement, now partly filled with debris, and kept on toward another wall.
"I'm going through that, too!" cried Tom.
And he did, knocking it down and sending his tank over the piled-up ruins, while the machine guns barked, coughed and spluttered, as Ned and the others inside the tank held back the firing levers.
Right through the opposite wall, as through the one she had already demolished, the tank careened on her way, to emerge, rather battered and dust-covered, on the other side of what was left of the factory. And there was not much of it left. Tank A had well-nigh completed its demolition.
"If there'd been a nest of Germans in there," said Tom, as he brought the machine to a stop in a field beyond the factory, "they'd have gotten out in a hurry."
"Or taken the consequences," added Ned, as he wiped the sweat from his powder-blackened and oil-smeared face. "I certainly kept my gun going."
"Yes, and so did the others," reported one of the mechanics, as he emerged from the "cubby hole," where the great motors had now ceased their hum and roar.
"How'd she stand it?" asked Tom.
"All right inside," answered the man. "I was wondering how she looks from the outside."
"Oh, it would take more than that to damage her," said Tom, with pardonable pride. "That was pie for her! Solid concrete, which she may have to chew up on the Western front, may present another kind of problem, but I guess she'll be able to master that too. Well, let's have a look."
He and Ned, with some of the crew and gunners, went outside the tank. She was a sorry-looking sight, very different from the trim appearance she had presented when she first left the shop. Bricks, bits of stone, and piles of broken cement in chunks and dust lay thick on her broad back. But no real damage had been done, as a hasty examination showed.
"Well, are you satisfied, Tom?" asked his chum.
"Yes, and more," was the answer. "Of course this wasn't the hardest test to which she could have been submitted, but it will do to show what punishment she can stand. Being shot at from big guns is another matter. I'll have to wait until she gets to Flanders to see what effect that will have. But I know the kind of armor skin she has, and that doesn't worry me. There's one thing more I want to do while I have her out now."
"What's that?" asked Ned.
"Take her for a long trip cross country, and then shove her through some extra heavy barbed wire. I'm certain she'll chew that up, but I want to see it actually done. So now, if you want to come along, Ned, we'll go cross country."
"I'm with you!"
"Get inside then. We'll let the dust and masonry blow and rattle off as we go along."
The tank started off across the fields, which stretched for many miles on either side of the deserted factory, when suddenly Ned, who was again at his post in the observation tower, called:
"Look, Tom!"
"What at?"
"That corner of the factory which is still standing. Look at those men coming out and running away!"
Ned pointed, and his chum, leaning over from the steering wheel and controls, gave a start of surprise as he saw three figures clambering down over the broken debris and making their way out of what had once been a doorway.
"Did they come out of the factory, Ned?"
"They surely did! And unless I miss my guess they were in it, or around it, when we went through like a fellow carrying the football over the line for a touchdown."
"In there when the tank broke open things?"
"I think so. I didn't see them before, but they certainly ran out as we started away."
"This has got to be looked into!" decided Tom. "Come on, Ned! It may be more of that spy business!"
Tom Swift stopped the tank and prepared to get out.
"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.
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 halfway. 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.