TOM SWIFT AND HIS WAR TANK

or

Doing His Bit For Uncle Sam

By

VICTOR APPLETON

CONTENTS

 I Past Memories II Tom's Indifference III Ned is Worried IV Queer Doings V "Is He a Slacker?" VI Seeing Things VII Up a Tree VIII Detective Rad IX A Night Test X A Runaway Giant XI Tom's Tank XII Bridging a Gap XIII Into a Trench XIV The Ruined Factory XV Across Country XVI The Old Barn XVII Veiled Threats XVIII Ready for France XIX Tom Is Missing XX The Search XXI A Prisoner XXII Rescued XXIII Gone XXIV Camouflaged XXV Foiled

Chapter I

Past Memories

Ceasing his restless walk up and down the room, Tom Swift strode to thewindow and gazed across the field toward the many buildings, wheremachines were turning out the products evolved from the brains of hisfather and himself. There was a worried look on the face of the younginventor, and he seemed preoccupied, as though thinking of somethingfar removed from whatever it was his eyes gazed upon. 

"Well, I'll do it!" suddenly exclaimed Tom. "I don't want to, but Iwill. It's in the line of 'doing my bit, ' I suppose; but I'd rather itwas something else. I wonder--"

"Ha! Up to your old tricks, I see, Tom!" exclaimed a voice, in whichenergy and friendliness mingled pleasingly. "Up to your old tricks!"

"Oh, hello, Mr. Damon!" cried Tom, turning to shake hands with anelderly gentleman--that is, elderly in appearance but not in action, for he crossed the room with the springing step of a lad, and there wasthe enthusiasm of youth on his face. "What do you mean--my old tricks?"

"Talking to yourself, Tom. And when you do that it means there issomething in the wind. I hope, as a sort of side remark, it isn't rainthat's in the wind, for the soldiers over at camp have had enough waterto set up a rival establishment with Mr. Noah. But there's somethinggoing on, isn't there? Bless my memorandum book, but don't tell methere isn't, or I shall begin to believe I have lost all my deductivepowers of reasoning! I Come in here, after knocking two or three times, to which you pay not the least attention, and find you mysteriouslymurmuring to yourself. 

"The last time that happened, Tom, was just before you started to digthe big tunnel--No, I'm wrong. It was just before you started for theLand of Wonders, as we decided it ought to be called. You were talkingto yourself then, when I walked in on you, and--Say, Tom!" suddenlyexclaimed Mr. Damon eagerly, "don't tell me you're going off on anotherwild journey like that--don't!"

"Why?" asked Tom, smiling at the energy of his caller. 

"Because if you are, I'll want to go with you, of course, and if I goit means I'll have to start in as soon as I can to bring my wife aroundto my way of thinking. The last time I went it took me two weeks to gether to consent, and then she didn't like it. So if--"

"No, Mr. Damon, " interrupted Tom, "I don't count on going on any sortof a trip--that is, any long one. I was just getting ready to take alittle spin in the Hawk, and if you'd like to come along--"

"You mean that saucy little airship of yours, Tom, that's always tryingto sit down on her tail, or tickle herself with one wing?"

"That's the Hawk!" laughed Tom; "though that tickling business youspeak of is when I spiral. Don't you like it?"

"Can't say I do, " observed Mr. Damon dryly. 

"Well, I'll promise not to try any stunts if you come along, " Tom wenton. 

"Where are you going?" asked his friend. 

"Oh, no place in particular. As you surmised, I've been doing a bit ofthinking, and--"

"Serious thinking, too, Tom!" interrupted Mr. Damon. "Excuse me, but Icouldn't help overhearing what you said. It was something about goingto do something though you didn't want to, and that it was part of your'bit'. That sounds like soldier talk. Are you going to enlist, Tom?"

"No. "

"Um! Well, then--"

"It's something I can't talk about, Mr. Damon, even to you, as yet, "Tom said, and there was a new quality in his voice, at which his friendlooked up in some surprise. 

"Oh, of course, Tom, if it's a secret--"

"Well, it hasn't even got that far, as yet. It's all up in the air, soto speak. I'll tell you in due season. But, speaking of the air, let'sgo for a spin. It may drive some of the cobwebs out of my brain. Did Ihear you say you thought it would rain?"

"No, it's as clear as a bell. I said I hoped it wouldn't rain for thesake of the soldiers in camp. They've had their share of wet weather, and, goodness knows, they'll get more when they get to Flanders. Itseems to do nothing but rain in France. "

"It is damp, " agreed Tom. "And, come to think of it, they are going tohave some airship contests over at camp to-day--for the men who arebeing trained to be aviators, you know. It just occurred to me that wemight fly over there and watch them. "

"Fine!" cried Mr. Damon. "That's the very thing I should like. I'lltake a chance in your Hawk, Tom, if you'll promise not to try anyspiral stunts. "

"I promise, Mr. Damon. Come on! I'll have Koku run the machine out andget her ready for a flight to Camp. It's a good day for a jaunt in theair. "

"Get out the Hawk, Koku, " ordered the young inventor, as he motioned toa big man--a veritable giant--who nodded to show he understood. Kokuwas really a giant, one of a race of strange beings, and Tom Swift hadbrought the big man with him when he escaped from captivity, as thosewill remember who have read that book. 

"Going far, Tom?" asked an aged man, coming to the door of one of themany buildings of which the shed where the airship was kept formed one. 

"Not very far, Father, " answered the young inventor. "Mr. Damon and Iare going for a little spin over to Camp Grant, to see some aircraftcontests among the army birdmen. "

"Oh, all right, Tom. I just wanted to tell you that I think I've gottenover that difficulty you found with the big carburetor you were workingon. You didn't say what you wanted it for, except that it was for aheavy duty gasolene engine, and you couldn't get the needle valve towork as you'd like. I think I've found a way. "

"Good, Dad! I'll look at it when I come back. That Carburetor didbother me, and if I can get that to work--well, maybe we'll havesomething soon that will--"

But Tom did not finish his sentence, for Koku was getting the aircraftin operation and Mr. Damon was already taking his place behind thepilot's seat, which would be occupied by Tom. 

"All ready, are you, Koku?" asked the young inventor. 

"All ready, Master, " answered the giant. 

There was a roar like that of a machine gun as the Hawk's engine spunthe propeller, and then, after a little run across the sod, it mountedinto the air, carrying Tom and Mr. Damon with it. 

"Mind you, Tom, no stunts!" called the visitor to the young inventorthrough the speaking tube apparatus, which enabled a conversation to becarried on, even above the roar of the powerful engine. "Bless myovershoes! if you try, looping the loop with me--"

"I won't do anything like that!" promised Tom. 

Away they soared, swift as a veritable hawk, and soon, after there hadunrolled below their eyes a succession of fields and forest, there cameinto view rows and rows of small brown objects, among which beings, like ants, seemed crawling about. 

"There's the Camp!" exclaimed Tom. 

"I see, " and Mr. Damon nodded. 

As they approached, they saw, starting up from a green space amid thebrown tents, what appeared to be big bugs of a dirty white colorsplotched with green. 

"The aircraft--and they have camouflage paint on, " said Tom. "We canwatch 'em from up here!"

Mr. Damon nodded, though Tom could not see him, sitting in front of hisfriend as he was. 

Up and up circled the army aircraft, and they seemed to bow and nod agreeting to the Hawk, which was soon in the midst of them. Tom and Mr. Damon, flying high, though at no great speed, looked at the maneuversof the veterans and the learners--many of whom might soon be engagingthe Boches in far-off France. 

"Some of 'em are pretty good!" called Tom, through the tube. "That onefellow did the loop as prettily as I've ever seen it done, " and TomSwift had a right to speak as one of authority. 

Tom and his friend watched the aircraft for some time, and then startedoff in a long flight, attaining a high speed, which, at first, made Mr. Damon gasp, until he became used to it. He was no novice at flying, andhad even operated aeroplanes himself, though at no great height. 

Suddenly the Hawk seemed to falter, almost as does a bird stricken by ahunter's gun. The craft seemed to hang in the air, losing motion asthough about to plunge to earth unguided. 

"What's the matter?" cried Mr. Damon. 

"One of the control wires broken!" was Tom's laconic answer. "I'll haveto volplane down. Sit tight, there's no danger!"

Mr. Damon knew that with so competent a pilot as Tom Swift in theforward seat this was true, but, nevertheless, he was a bit nervousuntil he felt the smooth, gliding motion, with now and then an upwardtilt, which showed that Tom was coming down from the upper regions in aseries of long glides. The engine had stopped, and the cessation of thethundering noise made it possible for Tom and his passenger to talkwithout the use of the speaking tube. 

"All right?" asked Mr. Damon. 

"All right, " Tom answered, and a little later the machine was rollinggently over the turf of a large field, a mile or so from the camp. 

Before Tom and Mr. Damon could get out of their seats, a man, seeminglyspringing up from some hollow in the ground, walked toward them. 

"Had an accident?" he asked, in what he evidently meant for a friendlyvoice. 

"A little one, easily mended, " Tom answered. 

He was about to take off his goggles, but at sight of the man's face achange came over the countenance of Tom Swift, and he replaced the eyeprotectors. Then Tom turned to Mr. Damon, as if to ask a question, butthe stranger came so close, evidently curious to see the aircraft atclose quarters, that the young inventor could not speak without beingoverheard. 

Tom got out his kit of tools to repair the broken control, and the manwatched him curiously. As he tinkered away, something was stirringamong the past memories of the inventor. A question he asked himselfover and over again was:

"Where have I seen this man before? His face is familiar, but I can'tplace him. He is associated with something unpleasant. But where have Iseen this man before?"

Chapter II

Tom's Indifference

"Did you make this machine yourself?" asked the stranger of Tom, as theyoung inventor worked at the damaged part of his craft. 

Mr. Damon had also alighted, taken off his goggles, and was lookingaloft, where the army aircraft were going through various evolutions, and down below, where the young soldiers were drilling under suchconditions, as far as possible, as they might meet with when some oftheir number went "over the top. " Mr. Damon was murmuring to himselfsuch remarks as:

"Bless my fountain pen! look at that chap turning upside down! Bless myinkwell!"

"I beg your pardon, " remarked Tom Swift, following the remark of theman, whose face he was trying to recall. It was not that Tom had notheard the question, but he was trying to gain time before answering. 

"I asked if you made this machine yourself, " went on the man, as hepeered about at the Hawk. "It isn't like any I've ever seen before, andI know something about airships. It has some new wrinkles on it, and Ithought you might have evolved them yourself. Not that it's an amateuraffair, by any means!" he added hastily, as if fearing the younginventor might resent the implication that his machine was a home-madeproduct. 

"Yes, I originated this, " answered Tom, as he put a new turn-buckle inplace; "but I didn't actually construct it--that is, except for somesmall parts. It was made in the shop--"

"Over at the army construction plant, I presume, " interrupted the manquickly, as he motioned toward the big factory, not far from Shopton, where aircraft for Uncle Sam's Army were being turned out by thehundreds. 

"Might as well let him think that, " mused Tom; "at least until I canfigure out who he is and what he wants. "

"This is different from most of those up there, " and the strangerpointed toward the circling craft on high. "A bit more speedy, I guess, isn't it?"

"Well, yes, in a way, " agreed Tom, who was lending over his craft. Hestole a side look at the man. The face was becoming more and morefamiliar, yet something about it puzzled Tom Swift. 

"I've seen him before, and yet he didn't look like that, " thought theyoung inventor. "It's different, somehow. Now why should my memory playme a trick like this? Who in the world can he be?"

Tom straightened up, and tossed a monkey wrench into the tool box. 

"Get everything fixed?" asked the stranger. 

"I think so, " and the young inventor tried to make his answer pleasant. "It was only a small break, easily fixed. "

"Then you'll be on your way again?"

"Yes. Are you ready?" called Tom to Mr. Damon. 

"Bless my timetable, yes! I didn't think you'd start back again sosoon. There's one young fellow up there who has looped the loop threetimes, and I expect him to fall any minute. "

"Oh, I guess he knows his business, " Tom said easily. "We'll begetting back now. "

"One moment!" called the man. "I beg your pardon for troubling you, butyou seem to be a mechanic, and that's just the sort of man I'm lookingfor. Are you open to an offer to do some inventive and constructivework?"

Tom was on his guard instantly. 

"Well, I can't say that I am, " he answered. "I am pretty busy--"

"This would pay well, " went on the man eagerly. "I am a stranger aroundhere, but I can furnish satisfactory references. I am in need of a goodmechanic, an inventor as well, who can do what you seem to have done sowell. I had hopes of getting some one at the army plant. "

"I guess they're not letting any of their men go, " said Tom, as Mr. Damon climbed to his seat in the Hawk. 

"No, I soon found that out. But I thought perhaps you--"

Tom shook his head. 

"I'm sorry, " he answered, "but I'm otherwise engaged, and very busy. "

"One moment!" called the man, as he saw Tom about to start "Is theSwift Company plant far from here?"

Tom felt something like a thrill go through him. There was anunexpected note in the man's voice. The face of the young inventorlightened, and the doubts melted away. 

"No, it isn't far, " Tom answered, shouting to be heard above thecrackling bangs of the motor. And then, as the craft soared into theair, he cried exultingly:

"I have it! I know who he is! The scoundrel! His beard fooled me, andhe probably didn't know me with these goggles on. But now I know him!"

"Bless my calendar!" cried Mr. Damon. "What are you talking about?"

But Tom did not answer, for the reason that just then the Hawk fellinto an "air pocket, " and needed all his attention to straighten herout and get her on a level course again. 

And while Tom Swift is thus engaged in speeding his aircraft along theupper regions toward his home, it will take but a few moments toacquaint my new readers with something of the history of the younginventor. Those who have read the previous books in this series need betold nothing about our hero. 

Tom Swift was an inventor of note, as was his father. Mr. Swift was nowquite aged and not in robust health, but he was active at times andoften aided Tom when some knotty point came up. 

Tom and his father lived on the outskirts of the town of Shopton, andnear their home were various buildings in which the different machinesand appliances were made. Tom's mother was dead, but Mrs. Baggert, thehousekeeper, was as careful in looking after Tom and his father as anywoman could be. 

In addition to these three, the household consisted of EradicateSampson, an aged colored servant, and, it might almost be added, hismule Boomerang; but Boomerang had manners that, at times, did not makehim a welcome addition to any household. Then there was the giant Koku, one of two big men Tom had brought back with him from the land wherethe young inventor had been held captive for a time. 

The first book of this series is called "Tom Swift and His MotorCycle, " and it was in acquiring possession of that machine that Tom methis friend Mr. Wakefield Damon, who lived in a neighboring town. Mr. Damon owned the motor cycle originally, but when it attempted to climba tree with him he sold it to Tom. 

Tom had many adventures on the machine, and it started him on hisinventive career. From then on he had had a series of surprisingadventures. He had traveled in his motor boat, in an airship, and thenhad taken to a submarine. In his electric runabout he showed what thespeediest car on the road Could do, and when he sent his wirelessmessage, the details of which can be found set down in the volume ofthat name, Tom saved the castaways of Earthquake Island. 

Tom Swift had many other thrilling escapes, one from among the diamondmakers, and another from the caves of ice; and he made the quickestflight on record in his sky racer. 

Tom's wizard camera, his great searchlight, his giant cannon, his phototelephone, his aerial warship and the big tunnel he helped to dig, brought him credit, fame, and not a little money. He had not long beenback from an expedition to Honduras, dubbed "the land of wonders, " whenhe was again busy en some of his many ideas. And it was to get somerelief from his thoughts that he had taken the flight with Mr. Damon onthe day the present story opens. 

"What are you so excited about, Tom?" asked his friend, as the Hawkalighted near the shed hack of the young inventor's home. "Bless myscarf pin! but any one would think you'd just discovered the truemethod of squaring the circle. "

"Well, it's almost as good as that, and more practical, " Tom said, witha smile, as he motioned to Koku to put away the aircraft "I know whothat man is, now. "

"What man, Tom?"

"The one who was questioning me when I was fixing the airship. I keptpuzzling and puzzling as to his identity, and, all at once, it came tome. Do you know who he is, Mr. Damon?"

"No, I can't say that I do, Tom. But, as you say, there was somethingvaguely familiar about him. It seemed as if I must have seen himbefore, and yet--"

"That's just the way it struck me. What would you say if I told youthat man was Blakeson, of Blakeson and Grinder, the rival tunnelcontractors who made such trouble for us?"

"You mean down in Peru, Tom?"

"Yes. "

Mr. Damon started in surprise, and then exclaimed:

"Bless my ear mufflers, Tom, but you're right! That was Blakeson! Ididn't know him with his beard, but that was Blakeson, all right! Blessmy foot-warmer! What do you suppose he is doing around here?"

"I don't know, Mr. Damon, but I'd give a good deal to know. It isn'tany good, I'll wager on that. He didn't seem to know me or you, either--unless he did and didn't let on. I suppose it was because ofmy goggles--and you were gazing up in the air most of the time. I don'tthink he knew either of us. "

"It didn't seem so, Tom. But what is he doing here? Do you think he isworking at the army camp, or helping make Liberty Motors for theaircraft that are going to beat the Germans?"

"Hardly. He didn't seem to be connected with the camp. He wanted amechanic, and hinted that I might do. Jove! if he really didn't knowwho I was, and finds out, say! won't he be surprised?"

"Rather, " agreed Mr Damon. "Well, Tom, I bad a nice little ride. Andnow I must be getting back. But if you contemplate a trip anywhere, don't forget to let me know. "

"I don't count on going anywhere soon, " Tom answered. "I have somethingon hand that will occupy all my time, though I don't just like it. However, I'm going to do my best, " and he waved good-bye to Mr. Damon, who went off blessing various parts of his anatomy or clothing, an oddhabit he had. 

As Tom turned to go into the house, the unsettled look still on hisface, some one hailed him. 

"I say, Tom. Hello! Wait a minute! I've got something to show you!"

"Oh, hello, Ned Newton!" Called back the young inventor. "Well, ifit's Liberty Bonds, you don't need to show me any, for dad and I willbuy all we can without seeing them. "

"I know that, Tom, and it was a dandy subscription you gave me. Ididn't come about that, though I may be around the next time Uncle Samwants the people to dig down in their socks. This is somethingdifferent, " and Ned Newton, a young banker of Shopton and a lifelongfriend of Tom's, drew a paper from his pocket as he advanced across thelawn. 

"There, Tom Swift!" he cried, flipping out an illustrated page, evidently from some illustrated newspaper. "There's the very latestfrom the other side. A London banker friend of mine sent it to me, andit got past the censor all right. It's the first authentic photographof the newest and biggest British tank. Isn't that a wonder?"

Ned held up the paper which had in it a fullpage photograph of amonster tank--those weird machines traveling on endless steel belts ofcaterpillar construction, armored, riveted and plated, with machineguns bristling here and there. 

"Isn't that great, Tom? Can you beat it? It's the most wonderfulmachine of the age, even counting some of yours. Can you beat it?"

Tom took the paper indifferently, and his manner surprised his chum. 

"Well, what's the matter, Tom?" asked Ned. "Don't you think that great?Why don't you say something? You don't mean to say you've seen thatpicture before?"

"No, Ned. "

"Then what's the matter with you? Isn't that wonderful?"

Chapter III

Ned is Worried

Tom Swift did not answer for several seconds. He stood holding thepaper Ned had given him, the sun slanting on the picture of the bigBritish tank. But the young inventor did not appear to see it. Instead, his eyes were as though contemplating something afar off. 

"Well, this gets me!" cried Ned, his voice showing impatience. "Here Igo and get a picture of the latest machine the British armies aresmashing up the Boches with, and bring it to you fresh from the mail--Ieven quit my Liberty Bond business to do it, and I know some dandyprospects, too--and here you look at it like a--like a fish!" burst outNed. 

"Say, old man, I guess that's right!" admitted Tom. "I wasn't thinkingabout it, to tell you the truth. "

"Why not?" Ned demanded. "Isn't it great, Tom? Did you ever seeanything like it?"

"Yes. "

"You did?" Cried Ned, in surprise. "Where? Say, Tom Swift, are youkeeping something from me?"

"I mean no, Ned. I never have seen a British tank. "

"Well, did you ever see a picture like this before?" Ned persisted. 

"No, not exactly like that But--"

"Well, what do you think of it?" cried the young banker, who was givingmuch of his time to selling bonds for the Government. "Isn't it great?"

Tom considered a moment before replying. Then he said slowly:

"Well, yes, Ned, it is a pretty good machine. But--"

"'But!' Howling tomcats! Say, what's the 'matter with you, anyhow, Tom?This is great! 'But!' 'But me no buts!' This is, without exception, thegreatest thing out since an airship. It will win the war for us and theAllies, too, and don't you forget it! Fritz's barbed wire and dugoutsand machine gun emplacements can't stand for a minute against thesetanks! Why, Tom, they can crawl on their back as well as any other way, and they don't mind a shower of shrapnel or a burst of machine gunlead, any more than an alligator minds a swarm of gnats. The only thingthat makes 'em hesitate a bit is a Jack Johnson or a Bertha shell, andit's got to be a pretty big one, and in the right place, to do muchdamage. These tanks are great, and there's nothing like 'em. "

"Oh, yes there is, Ned!"

"There is!" cried Ned. "What do you mean?"

"I mean there may be something like them--soon. "

"There may? Say, Tom--"

"Now don't ask me a lot of questions, Ned, for I can't answer them. When I say there may be something like them, I mean it isn't beyond therealms of possibility that some one--perhaps the Germans--may turn outeven bigger and better tanks. "

"Oh!" And Ned's voice showed his disappointment. "I thought maybe youwere in on that game yourself, Tom. Say, couldn't you get up somethingalmost as good as this?" and he indicated the picture in the paper. "Isn't that wonderful?"

"Oh, well, it's good, Ned, but there are others. Yes, Dad, I'm coming, "he called, as he saw his father beckoning to him from a distantbuilding. 

"Well, I've got to get along, " said Ned. "But I certainly amdisappointed, Tom. I thought you'd go into a fit over thispicture--it's one of the first allowed to get out of England, my Londonfriend said. And instead of enthusing you're as cold as a clam;" andNed shook his head in puzzled and disappointed fashion as he walkedslowly along beside the young inventor. 

They passed a new building, one of the largest in the group of the manycomprising the Swift plant. Ned looked at the door which bore a noticeto the effect that no one was admitted unless bearing a special permit, or accompanied by Mr. Swift or Tom. 

"What's this, Tom?" asked Ned. "Some new wrinkle?"

"Yes, an invention I'm working on. It isn't in shape yet to be seen. "

"It must be something big, Tom, " observed Ned, as he viewed the largebuilding. 

"It is. "

"And say, what a whopping big fence you've got around the back yard!"went on the young banker. "Looks like a baseball field, but it wouldtake some scrambling on the part of a back-lots kid to get over it. "

"That's what it's for--to keep people out. "

"I see! Well, I've got to get along. I'm a bit back in my day's quotaof selling Liberty Bonds, and I've got to hustle. I'm sorry I botheredyou about that tank picture, Tom. "

"Oh, it wasn't a bother--don't think that for a minute, Ned! I was gladto see it. "

"Well, he didn't seem so, and his manner was certainly queer, " musedNed, as he walked away, and turned in time to see Tom enter the newbuilding, which had such a high fence all around it. "I never saw himmore indifferent. I wonder if Tom isn't interested in seeing Uncle Samhelp win this war? That's the way it struck me. I thought surely Tomwould go up in the air, and say this was a dandy, " and Ned unfolded thepaper and took another look at the British tank photograph. "If there'sanything can beat that I'd like to see it, " he mused. 

"But I suppose Tom has discovered some new kind of air stabilizer, or adifferent kind of carburetor that will vaporize kerosene as well asgasolene. If he has, why doesn't he offer it to Uncle Sam? I wonder ifTom is pro-German? No, of Course he can't be!" and Ned laughed at hisown idea. 

"At the same time, it is queer, " he mused on. "There is something wrongwith Tom Swift. "

Once more Ned looked at the picture. It was a representation of one ofthe newest and largest of the British tanks. In appearance these arenot unlike great tanks, though they are neither round nor square, beingshaped, in fact, like two wedges with the broad ends put together, andthe sharper ends sticking out, though there is no sharpness to a tank, the "noses" both being blunt. 

Around each outer edge runs an endless belt of steel plates, hingedtogether, with ridges at the joints, and these broad belts of steelplates, like the platforms of some moving stairways used in departmentstores, moving around, give motion to the tank. 

Inside, well protected from the fire of enemy guns by steel plates, arethe engines for driving the belts, or caterpillar wheels, as they arecalled. There is also the steering apparatus, and the guns that fire onthe enemy. There are cramped living and sleeping quarters for thetank's crew, more limited than those of a submarine. 

The tank is ponderous, the smallest of them, which were those firstconstructed, weighing forty-two tons, or about as much as a good-sizedrailroad freight car. And it is this ponderosity, with its slow butresistless movement, that gives the tank its power. 

The tank, by means of the endless belts of steel plates, can travelover the roughest country. It can butt into a tree, a stone wall, or ahouse, knock over the obstruction, mount it, crawl over it, and slidedown into a hole on the other side and crawl out again, on the level, or at an angle. Even if overturned, the tanks can sometimes rightthemselves and keep on. At the rear are trailer wheels, partly used insteering and partly for reaching over gaps or getting out of holes. Thetanks can turn in their own length, by moving one belt in one directionand the other oppositely. 

Inside there is nothing much but machinery of the gasolene type, andthe machine guns. The tank is closed except for small openings out ofwhich the guns project, and slots through which the men inside look outto guide themselves or direct their fire. 

Such, in brief, is a British tank, one of the most powerful andeffective weapons yet loosed against the Germans. They are useful intearing down the barbed-wire entanglements on the Boche side of NoMan's Land, and they can clear the way up to and past the trenches, which they can straddle and wriggle across like some giant worm. 

"And to think that Tom Swift didn't enthuse over these!" murmured Ned. "I wonder what's the matter with him!"

Chapter IV

Queer Doings

There was a subdued air of activity about the Swift plant. Subdued, owing to the fact that it was mostly confined to one building--the new, large one, about which stretched a high and strong fence, made withtongue-and-groove boards so that no prying eyes might find a crack, even, through which to peer. 

In and out of the other buildings the workmen went as they pleased, though there were not many of them, for Tom and his father weredevoting most of their time and energies to what was taking place inthe big, new structure. But here there was an entirely differentprocedure. 

Workmen went in and out, to be sure, but each time they emerged theywere scrutinized carefully, and when they went in they had to exhibittheir passes to a man on guard at the single entrance; and the passeswere not scrutinized perfunctorily, either. 

Near the building, about which there seemed to be an air of mystery, one day, a week after the events narrated in the opening chapters, strolled the giant Koku. Not far away, raking up a pile of refuse, wasEradicate Sampson, the aged colored man of all work. Eradicateapproached nearer and nearer the entrance to the building, pursuing histask of gathering up leaves, dirt and sticks with the teeth of hisrake. Then Koku, who had been lounging on a bench in the shade of atree, Called:

"No more, Eradicate!"

"No mo' whut?" asked the negro quickly. "I didn't axt yo' fo' nuffinyit!"

"No more come here!" said the giant, pointing to the building andspeaking English with an evident effort. "Master say no one come tooclose. "

"Huh! He didn't go fo' t' mean me!" exclaimed Eradicate. "I kin goanywheres; I kin!"

"Not here!" and Koku interposed his giant frame between the old man andthe first step leading into the secret building. "You no come in here. "

"Who say so?"

"Me--I say so! I on guard. I what you call specialpoliceman--detectiff--no let enemies in!"

"Huh! You's a hot deteckertiff, yo' is!" snorted Eradicate. "Anyhow, dem orders don't mean me! I kin go anywhere, I kin!"

"Not here!" said Koku firmly. "Master Tom say let nobody come near butworkmen who have got writing-paper. You no got!"

"No, but I kin git one, an' I's gwine t' hab it soon! I'll see MassaTom, dat's whut I will. I guess yo' ain't de only deteckertiff on deplace. I kin go on guard, too!" and Eradicate, dropping his rake, strolled away in his temper to seek the young inventor. 

"Well, Rad, what is it?" asked Tom, as he met the colored man. Theyoung inventor was on his way to the mysterious shop. "What istroubling you?"

"It's dat dar giant. He done says as how he's on guard--adeteckertiff--an' I can't go nigh dat buildin' t' sweep up de refuse. "

"Well, that's right, Rad. I'd prefer that you keep away. I'm doingsome special work in there and it's--"

"Am it dangerous, Massa Tom? I ain't askeered! Anybody whut kin drivemah mule Boomerang--"

"I know, Eradicate, but this isn't so dangerous. It's just secret, andI don't want too many people about. You can go anywhere else exceptthere. Koku is on guard. "

"Den can't I be, Massa Tom?" asked the colored man eagerly. "I kinguard an' detect same as dat low-down, good-fo'-nuffin white trashKoku!"

Tom hesitated. 

"I suppose I could get you a sort of officer's badge, " he mused, halfaloud. 

"Dat's whut I want!" eagerly exclaimed Eradicate. "I ain't gwine habdat Koku--dat cocoanut--crowin' ober me! I kin guard an' detect asgood's anybody!"

And the upshot of it was that Eradicate was given a badge, and put on aspecial post, far enough from Koku to keep the two from quarreling, andwhere, even if he failed in keeping a proper lookout, the old servantcould do no harm by his oversight. 

"It'll please him, and won't hurt us, " said Tom to his father. "Kokuwill keep out any prying persons. "

"I suppose you are doing well to keep it a secret, Tom, " said Mr. Swift, "but it seems as if you might announce it soon. "

"Perhaps we may, Dad, if all goes well. I've given her a partialshop-tryout, and she works well. But there is still plenty to do. Did Itell you about meeting Blakeson?"

"Yes, and I can't understand why he should be in this vicinity. Do youthink he has had any intimation of what you are doing?"

"It's hard to say, and yet I would not be surprised. When Uncle Samcouldn't keep secret the fact of our first soldiers sailing for France. How can I expect to keep this secret? But they won't get any detailsuntil I'm ready, I'm sure of that. "

"Koku is a good discourager, " said Mr. Swift, with a chuckle. "Youcouldn't have a better guard, Tom. "

"No, and if I can keep him and Eradicate from trying to pull off rivaldetective stunts, or 'deteckertiff, ' as Rad calls it, I'll be allright. Now let's have another go at that carburetor. There's our weakpoint, for it's getting harder and harder all the while to gethigh-grade gasolene, and we'll have to come to alcohol of low proof, orkerosene, I'm thinking. "

"I wouldn't be surprised, Tom. Well, perhaps we can get up a new styleof carburetor that will do the trick. Now look at this needle valve;I've given it a new turn, " and father and son went into technicaldetails connected with their latest invention. 

These were busy days at the Swift plant. Men came and went--men withqueerly shaped parcels frequently--and they were admitted to the bignew building after first passing Eradicate and then Koku, and it wouldbe hard to say which guard was the more careful. Only, of course, Kokuhad the final decision, and more than one person was turned back afterEradicate had passed him, much to the disgust of the negro. 

"Pooh! Dat giant don't know a workman when he sees 'im!" snortedEradicate. "He so lazy his own se'f dat he don't know a workman! Ef Isees a spy, Massa Tom, or a crook, I's gwine git him, suah pop!"

"I hope you do, Rad. We can't afford to let this secret get out, " saidthe young inventor. 

It was one evening, when taking a short cut to his home, that Mr. Nestor, the father of Mary Nestor, in whom Tom was more than ordinarilyinterested, passed not far from the big enclosure which was guarded, onthe factory side, day and night. Inside, though out of sight and hiddenby the high fence, were other guards. 

As Mr. Nestor passed along the fence, rather vaguely wondering why itwas so high, tight and strong, he felt the ground trembling beneath hisfeet. It rumbled and shook as though a distant train were passing, andyet there was none due now, for Mr. Nestor had just left one, andanother would not arrive for an hour. 

"That's queer, " mused Mary's father. "If I didn't know to the contrary, I'd say that sounded like heavy guns being fired from a distance, orelse blasting. It seems to come from the Swift place, " he went on. "Iwonder what they're up to in there. "

Suddenly the rumbling became more pronounced, and mingled with it, inthe dusk of the evening, were the shouts of men. 

"Look out!" some one cried. "She's going for the fence!"

A second later there was a cracking and straining of boards, and thefence near Mr. Nestor bulged out as though something big, powerful andmighty were pressing it from the inner side. 

But the fence held, or else the pressure was removed, for the bulgewent back into place, though some of the boards were splintered. 

"Have to patch that up in the morning, " called another voice, and Mr. Nestor recognized it as that of Tom Swift. 

"What queer doings are going on here?" mused Mary's father. "Have theygot a wild bull shut up in there, and is he trying to get out? Luckyfor me he didn't, " and he hurried on, the rumbling noise become fainteruntil it died away altogether. 

That night, after his supper and while reading the paper and smoking acigar, Mr. Nestor spoke to his daughter. 

"Mary, have you seen anything of Tom Swift lately?"

"Why, yes, Father. He was over for a little while the other night, buthe didn't stay long. Why do you ask?"

"Oh, nothing special. I just came past his place and I heard some queernoises, that's all. He's up to some more of his tricks, I guess. Has beenlisted yet?"

"No. 

"Is he going to?"

"I don't know, " and Mary seemed a bit put out by this simple question. "What do you mean by his tricks?" she asked, and a close observer mighthave thought she was anxious to get away from the subject of Tom'senlistment. 

"Oh, like that one when he sent you something in a box labeled'dynamite, ' and gave us all a scare. You can't tell what Tom Swift isgoing to do next. He's up to something now, I'll wager, and I don'tbelieve any good will come of it. "

"You didn't think so after he sent his wireless message, and saved usfrom Earthquake Island, " said Mary, smiling. 

"Hum! Well, that was different, " snapped Mr. Nestor. "This time I'msure he's up to some nonsense! The idea of crashing down a fence! Whydoesn't he enlist like the other chaps, or sell Liberty Bonds like NedNewton?" and Mr. Nestor looked sharply at his daughter. "Ned gave up abig salary as the Swifts financial man--a place he had held for ayear--to go back to the bank for less, just so he could help theGovernment in the financial end of this war. Is Tom doing as much forhis country?"

"I'm sure I don't know, " answered Mary; and soon after, with avertedface, she left the room. 

"Hum! Queer goings on, " mused Mr. Nestor. "Tom Swift may be all right, but he's got an unbalanced streak in him that will bear looking outfor, that's what I think!"

And having settled this matter, at least to his own satisfaction, Mr. Nestor resumed his smoking and reading. 

A little later the bell rang. There was a murmur of voices in the hall, and Mr. Nestor, half listening, heard a voice he knew. 

"There's Tom Swift now!" he exclaimed. "I'm going to find out why hedoesn't enlist!"

Chapter V

"Is He a Slacker?"

Mr. Nestor, whatever else he was, proved to be a prudent father. He didnot immediately go into the front room, whither Mary and Tom hastened, their voices mingling in talk and laughter. 

Mr. Nestor, after leaving the young folks alone for a while, with aloud "Ahem!" and a rattling of his paper as he laid it aside, startedfor the parlor. 

"Good-evening, Mr. Nestor!" said Tom, rising to shake hands with thefather of his young and pretty hostess. 

"Hello, Tom!" was the cordial greeting, in return. "What's going on upat your place?" went on Mr. Nestor, as he took a chair. 

"Oh, nothing very special, " Tom answered. "We're turning out differentkinds of machines as usual, and dad and I are experimenting, also asusual. "

"I suppose so. But what nearly broke the fence to-night?"

Tom started, and looked quickly at his host. 

"Were you there?" he asked quickly. 

"Well, I happened to be passing--took a short cut home--and I heardsome queer goings on at your place. I was speaking to Mary about them, and wondering--"

"Father, perhaps Tom doesn't want to talk about his inventions, "interrupted Mary. "You know some of them are secret--"

"Oh, I wasn't exactly asking for information!" exclaimed Mr. Nestorquickly. "I just happened to hear the fence crash, and I was wonderingif something was coming out at me. Didn't know but what that giant ofyours was on a rampage, Tom, " and he laughed. 

"No, it wasn't anything like that, " and Tom's voice was more sober thanthe occasion seemed to warrant. "It was one of our new machines, and itdidn't act just right. No great damage was done, though. How do youfind business, Mr. Nestor, since the war spirit has grown stronger?"asked Tom, and it seemed to both Mary and her father that the younginventor deliberately changed the subject. 

"Well, it isn't all it might be, " said the other. "It's hard to getgood help. A lot of our boys enlisted, and some were taken in thedraft. By the way, Tom, have they called on you yet?"

"No. Not yet. "

"You didn't enlist?"

"Ned Newton tried to, " broke in Mary, "but the quota for this localitywas filled, and they told him he'd better wait for the draft. Hewouldn't do that and tried again. Then the bank people heard about itand had him exempted. They said he was too valuable to them, and he hasbeen doing remarkably well in selling Liberty Bonds!" and Mary's eyessparkled with her emotions. 

"Yes, Ned is a crackerjack salesman!" agreed Tom, no lessenthusiastically. "He's sold more bonds, in proportion, for his bank, than any other in this county. Dad and I both took some, and havepromised him more. I am glad now that we let him go, although we valuedhis services highly. We hope to have him back later. "

"He can put me down for more bonds too!" said Mr. Nestor. "I'm goingto see Germany beaten if it takes every last dollar I have!"

"That's what I say!" Cried Mary. "I took out all my savings, except alittle I'm keeping to buy a wedding present for Jennie Morse. Did youknow she was going to get married, Tom?" she asked. 

"I heard so. "

"Well, all but what I want for a wedding present to her has gone intoLiberty Bonds. Isn't this a history-making time, Tom?"

"Indeed it is, Mary!"

"Everybody who has a part in it--whether he fights as a soldier or onlyknits like the Red Cross girls--will be telling about it for yearsafter, " went on the girl, and she looked at Tom eagerly. 

"Yes, " he agreed. "These are queer times. We don't know exactly wherewe're at. A lot of our men have been called. We tried to have some ofthem exempted, and did manage it in a few cases. "

"You did?" cried Mr. Nestor, as if in surprise. "You stopped men fromgoing to war!"

"Only so they could work on airship motors for the Government, " Tomquietly explained. 

"Oh! Well, of course, that's part of the game, " agreed Mary's father. "A lot more of our boys are going off next week. Doesn't it make youthrill, Tom, when you see them marching off, even if they haven't theiruniforms yet? Jove, if I wasn't too old, I'd go in a minute!"

"Father!" cried Mary. 

"Yes, I would!" he declared. "The German government has got to bebeaten, and we've got to do our bit; everybody has--man, woman andchild!"

"Yes, " agreed Tom, in a low voice, "that's very true. But every one, ina sense, has to judge for himself what the 'bit' is. We can't all dothe same. "

There was a little silence, and then Mary went over to the piano andplayed. It was a rather welcome relief, under the circumstances, fromthe conversation. 

"Mary, what do you think of Tom?" asked Mr. Nestor, when the visitorhad gone. 

"What do I think of him?" And she blushed. 

"I mean about his not enlisting. Do you think he's a slacker?"

"A slacker? Why, Father!"

"Oh, I don't mean he's afraid. We've seen proof enough of his courage, and all that. But I mean don't you think he wants stirring up a bit?"

"He is going to Washington to-morrow, Father. He told me so to-night. And it may be--"

"Oh, well, then maybe it's all right, " hastily said Mr. Nestor. "He maybe going to get a commission in the engineer corps. It isn't like TomSwift to hang back, and yet it does begin to look as though he caredmore for his queer inventions--machines that butt down fences than forhelping Uncle Sam. But I'll reserve judgment. "

"You'd better, Father!" and Mary laughed--a little. Yet there was aworried look on her face. 

During the next few nights Mr. Nestor made it a habit to take the shortcut from the railroad station, coming past the big fence that enclosedone particular building of the Swift plant. 

"I wonder if there's a hole where I could look through, " said Mr. Nestor to himself. "Of course I don't believe in spying on what anotherman is doing, and yet I'm too good a friend of Tom's to want to see himmake a fool of himself. He ought to be in the army, or helping UncleSam in some way. And yet if he spends all his time on some foolishcontraption, like a new kind of traction plow, what good is that? If Icould get a glimpse of it, I might drop a friendly hint in his ear. "

But there were no cracks in the fence, or, if there were, it was toodark to see them, and also too dark to behold anything on the otherside of the barrier. So Mr. Nestor, wondering much, kept on his way. 

It was a day or so after this that Ned Newton paid a visit to the Swifthome. Mr. Swift was not in the house, being out in one of the variousbuildings, Mrs. Baggert said. 

"Where's Tom?" asked the bond salesman. 

"Oh, he hasn't come back from Washington yet, " answered the housekeeper. 

"He is making a long stay. "

"Yes, he went about a week ago on some business. But we expect him backto-day. "

"Well, then I'll see him. I called to ask if Mr. Swift didn't want totake a few more bonds. We want to double our allotment for Shopton, andbeat out some of the other towns in this section. I'll go to see Mr. Swift. "

On his way to find Tom's father Ned passed the big building in front ofwhich Eradicate and Koku were on guard. They nodded to Ned, who passedthem, wondering much as to what it was Tom was so secretive about. 

"It's the first time I remember when he worked on an invention withouttelling me something about it, " mused Ned. "Well, I suppose it willall come out in good time. Anything new, Rad?"

"No, Massa Ned, nuffin much. I'm detectin' around heah; keepin'Dutchmen spies away!"

"And Koku is helping you, I suppose?"

"Whut, him? Dat big, good-fo'-nuffin white trash? No, sah! I'sdetectin' by mahse'f, dat's whut I is!" and Eradicate strutted proudlyup and down on his allotted part of the beat, being careful not toapproach the building too closely, for that was Koku's ground. 

Ned smiled, and passed on. He found Mr. Swift, secured his subscriptionto more bonds, and was about to leave when he heard a call down theroad and saw Tom coming in his small racing car, which had been takento the depot by one of the workmen. 

"Hello, old man!" cried Ned affectionately, as his chum alighted with ajump. "Where have you been?"

"Down to Washington. Had a bit of a chat with the President and gavehim some of my views. "

"About the war, I suppose?" laughed Ned. 

"Yes. "

"Did you get your commission?"

"Commission?" And there was a wondering look on Tom's face. 

"Yes. Mary Nestor said she thought maybe you were going to Washingtonto take an examination for the engineering corps or something likethat. Did you get made an officer?"

"No, " answered Tom slowly. "I went to Washington to get exempted. "

"Exempted?" Cried Ned, and his voice sounded strained. 

Chapter VI

Seeing Things

For a moment Tom Swift looked at his chum. Then something of what waspassing in the mind of the young bond salesman must have been reflectedto Tom, for he said, "Look here, old man; I know it may seem a bit strange to go to all thattrouble to get exempted from the draft, to which I am eligible, but, believe me, there's a reason. I can't say anything now, but I'll tellyou as soon as I can--tell everybody, in fact Just now it isn't inshape to talk about. "

"Oh, that's all right, Tom, " and Ned tried to make his voice soundnatural. "I was just wondering, that's all. I wanted to go to the frontthe worst way, but they wouldn't let me. I was sort of hoping youcould, and come back to tell me about it. "

"I may yet, Ned. "

"You may? Why, I thought--"

"Oh, I'm only exempted for a time. I've got certain things to do, and Icouldn't do 'em if I enlisted or was drafted. So I've been excused fora time. Now I've got a pile of work to do. What are you up to Ned? Sameold story?"

"Liberty Bonds--yes. Your father just took some more. "

"And so will I, Ned. I can do that, anyhow, even if I don't enlist. Putme down for another two thousand dollars' worth. "

"Say, Tom, that's fine! That will make my share bigger than I countedon. Shopton will beat the record. "

"That's good. We ought to pull strong and hearty for our home town. How's everything else?"

"Oh, so-so. I see Koku and Eradicate trying to outdo one another inguarding that part of your plant, " and Ned nodded toward the big newbuilding. 

"Yes, I had to let Rad play detective. Not that he can doanything--he's too old. But it keeps him and Koku from quarreling allthe while. I've got to be pretty careful about that shop. It's got asecret in it that--Well, the less said about it the better. "

"You're getting my curiosity aroused, Tom, " remarked Ned. 

"It'll have to go unsatisfied for a while. Wait a bit and I'll give youa ride. I've got to go over to Sackett on business, and if you're goingthat way I'll take you. "

"What in?"

"The Hawk. "

"That's me!" cried Ned. "I haven't been in an aircraft for some time. "

"Tell Miles to run her out, " requested Tom. "I've got to go in and sayhello to dad a minute, and then I'll be with you. "

"Seems like something was in the wind, Tom--big doings?" hinted Ned. 

"Yes, maybe there is. It all depends on how she turns out. "

"You might be speaking of the Hawk or--Mary Nestor!" said Ned, with asidelong look at his chum. 

"As it happens, it's neither one, " said Tom, and then he hastened away, to return shortly and guide his fleet little airship, the Hawk, on heraerial journey. 

From then on, at least for some time, neither Tom nor Ned mentioned thematters they had been discussing--Tom's failure to enlist, hisexemption, and what was being built in the closely guarded shop. 

Tom's business in Sackett did not take him long, and then he and Nedwent for a little ride in the air. 

"It's like old times!" exclaimed Ned, his eyes shining, though Tomcould not see them for two reasons. One was that Ned was sitting behindhim, and the other was that Ned wore heavy goggles, as did the youngpilot. Also, they had to carry on their talk through the speaking tubearrangement. 

"Yes, it is a bit like old times, " agreed Tom. "We've had some greatold experiences together, Ned, haven't we?"

"We surely have! I wonder if we'll have any more? When we were in thesubmarine, and in your big airship Say, that big one is the one Ialways liked! I like big things. "

"Do you?" asked Tom. "Well, maybe, when I get--"

But Tom did not finish, for the Hawk unexpectedly poked her nose intoan empty pocket in the air just then, and needed a firm hand on thecontrols. Furthermore, Tom decided against making the confidence thatwas on the tip of his tongue. 

At last the aircraft was straightened out and the pilot guided her ontoward the army encampment. 

"That's the place I'd like to be, " called Ned through the tube as thefaint, sweet notes of a bugle floated up from the parade ground. 

"Yes, it would be great, " admitted Tom. "But there are other things todo for Uncle Sam besides wearing khaki. "

"Tom's up to some game, " mused Ned. "I mustn't judge him too hastily, or I might make a mistake. And Mary mustn't, either. I'll tell her so. "

For Mary Nestor had spoken to Ned concerning Tom, and the curiouslysecretive air about certain of his activities. And the girl, moreover, had spoken rather coldly of her friend. Ned did not like this. It wasnot like Mary and Tom to be at odds. 

Once more the Hawk came to the ground, this time near the airship shedsadjoining the Swift works. Just as Tom and Ned alighted, one of theworkmen summoned the young inventor toward the shop, which was soclosely guarded by Koku and Eradicate on the outside. 

"I'll have to leave you, Ned, " remarked Tom, as he turned away from hischum. "There's a conference on about a new invention. "

"Oh, that's all right. Business is business, you know. I've got somebond calls to make myself. I'll see you later. "

"Oh, by the way, Ned!" exclaimed Tom, turning back for a moment, "I metan old friend the other day; or rather an old enemy. "

"Hum! When you spoke first, I thought you might mean ProfessorSwyington Bumper, that delightful scientist, " remarked Ned. "But hesurely was no enemy. "

"No; but I meant some one I met about the same time. I met Blakeson, one of the rival contractors when I helped dig the big tunnel. "

"Is that so? Where'd you meet him?"

"Right around here. It was certainly a surprise, and at first Icouldn't place him. Then the memory of his face came back to me, " andTom related the incident which had taken place the day he and Mr. Damonwere out in the Hawk. 

"What's he doing around here?" asked Ned. 

"That's more than I can say, " Tom answered. 

"Up to no good, I'll wager!"

"I agree with you, " came from Tom. "But I'm on the watch. "

"That's wise, Tom. Well, I'll see you later. "

During the week which followed this talk Ned was very busy on LibertyBond work, and, he made no doubt, his chum was engaged also. Thisprevented them from meeting, but finally Ned, one evening, decided towalk over to the Swift home. 

"I'll pay Tom a bit of a call, " he mused. "Maybe he'll feel more liketalking now. Some of the boys are asking why he doesn't enlist, andmaybe if I tell him that he'll make some explanation that will quietthings down a bit. It's a shame that Tom should be talked about. "

With this intention in view, Ned kept on toward his chum's house, andhe was about to turn in through a small grove of trees, which wouldlead to a path across the fields, when the young bond salesman wassurprised to hear some one running toward him. He could see no one, forthe path wound in and out among the trees, but the noise was plain. 

"Some one in a hurry, " mused Ned. 

A moment later he caught sight of a small lad named Harry Telfordrunning toward him. The boy had his hat in his hand, and was speedingthrough the fast-gathering darkness as though some one were after him. 

"What's the rush?" asked Ned. "Playing cops and robbers?" That was agame Tom and Ned had enjoyed in their younger days. 

"I--I'm runnin' away!" panted Harry. "I--I seen something!"

"You saw something?" repeated Ned. "What was it--a ghost?" and helaughed, thinking the boy would do the same. 

"No, it wasn't no ghost!" declared Harry, casting a look over hisshoulder. "It was a wild elephant that I saw, and it's down in a bigyard with a fence around it. "

"Where's that?" asked Ned. "The circus hasn't come to town thisevening, has it?"

"No, " answered Harry, "it wasn't no circus. I saw this elephant down inthe big yard back of one of Mr. Swift's factories. "

"Oh, down there, was it!" exclaimed Ned. "What was it like?"

"Well, I was walking along the top of the hill, " explained Harry, "andthere's one place where, if you climb a tree, you can look right downin the big fenced-in yard. I guess I'm about the only one that knowsabout it. "

"I don't believe Tom does, " mused Ned, "or he'd have had that tree cutdown. He doesn't want any spying, I take it. Well, what'd you see?" heasked Harry aloud. 

"Saw an elephant, I tell you!", insisted the younger boy. "I was inthe tree, looking down, for a lot of us kids has tried to peek throughthe fence and couldn't I wanted to see what was there. "

"And did you?" asked Ned. 

"I sure did! And it scared me, too, " admitted Harry. "All at once, whenI was lookin', I saw the big doors at the back of the shed open, andthe elephant waddled out. "

"Are you sure you weren't 'seeing things, ' like the little boy in thestory?" asked Ned. 

"Well, I sure did see something!" insisted Harry. "It was a great biggray thing, bigger'n any elephant I ever saw in any circus. It didn'tseem to have any tail or trunk, or even legs, but it went slow, justlike an elephant does, and it shook the ground, it stepped so hard!"

"Nonsense!" cried Ned. 

"Sure I saw it!" cried Harry. "Anyhow, " he added, after a moment'sthought, "it was as big as an elephant, though not like any I ever saw. "

"What did it do?" asked Ned. 

"Well, it moved around and then it started for the fence nearest me, where I was up in the tree. I thought it might have seen me, eventhough it was gettin' dark, and it might bust through; so I ran!"

"Hum! Well, you surely were seeing things, " murmured Ned, but, while hemade light of what the boy told him, the young bank Clerk was thinking:"What is Tom up to now?"

Chapter VII

Up a Tree

"Want to come and have a look?" asked Harry, as Ned paused in the patchof woods, which were in deeper darkness than the rest of thecountryside, for night was fast falling. 

"Have a look at what?" asked Ned, who was thinking many thoughts justthen. 

"At the elephant I saw back of the Swift factory. I wouldn't be skeeredif you came along. "

"Well, I'm going over to see Tom Swift, anyhow, " answered Ned, "so I'llwalk that way. You can come if you like. I don't care about spying onother people's property--"

"I wasn't spyin'!" exclaimed Harry quickly. "I just happened to look. And then I seen something. "

"Well, come on, " suggested Ned. "If there's anything there, we'll havea peep at it. "

His idea was not to try to see what Tom was evidently endeavoring toconceal, but it was to observe whence Harry had made his observation, and be in a position to tell Tom to guard against unexpected lookers-onfrom that direction. 

During the walk back along the course over which Harry had run sorapidly a little while before, Ned and the boy talked of what thelatter had seen. 

"Do you think it could be some new kind of elephant?" asked Harry. "Youknow Tom Swift brought back a big giant from one of his trips, andmaybe he's got a bigger elephant than any one ever saw before. "

"Nonsense!" laughed Ned. "In the first place, Tom hasn't been on anytrip, of late, except to Washington, and the only kind of elephantsthere are white ones. "

"Really?" asked Harry. 

"No, that was a joke, " explained Ned. "Anyhow, Tom hasn't any giantelephants concealed up his sleeve, I'm sure of that. "

"But what could this be?" asked Harry. "It moved just like some biganimal. "

"Probably some piece of machinery Tom was having carted from one shopto another, " went on the young bank clerk. "Most likely he had itcovered with a big piece of canvas to keep off the dew, and it was thatyou saw. "

"No, it wasn't!" insisted Harry, but he could not give any furtherdetails of what he had seen so that Ned could recognize it. They kepton until they reached the hill, at the bottom of which was the Swifthome and the grounds on which the various shops were erected. 

"Here's the place where you can look down right into the yard with thehigh fence around it, " explained Harry, as he indicated the spot. 

"I can't see anything. "

"You have to climb up the tree, " Harry went on. "Here, this is the one, and he indicated a stunted and gnarled pine, the green branches ofwhich would effectually screen any one who once got in it a few feetabove the ground. 

"Well, I may as well have a look, " decided Ned. "It can't do Tom anyharm, and it may be of some service to him. Here goes!"

Up into the tree he scrambled, not without some difficulty, for thebranches were close together and stiff, and Ned tore his coat in theeffort. But he finally got a position where, to his surprise, he couldlook down into the very enclosure from which Tom was so particular tokeep prying eyes. 

"You can see right down in it!" Ned exclaimed. 

"I told you so, " returned Harry. "But do you see--it?"

Ned looked long and carefully. It was lighter, now that they were outof the clump of woods, and he had the advantage of having the last glowof the sunset at his back. Even with that it was difficult to make outobjects on the surface of the enclosed field some hundred or more feetbelow. 

"Do you see anything?" asked Harry again. 

"No, I can't say I do, " Ned answered. "The place seems to be deserted. "

"Well, there was something there, " insisted Harry. "Maybe you aren'tlookin' at the right place. "

"Have a look yourself, then, " suggested Ned, as he got down, a task nomore to his liking than the climb upward had been. 

Harry made easier work of it, being smaller and more used to climbingtrees, a luxury Ned had, perforce, denied himself since going to workin the bank. 

Harry peered about, and then, with a sigh that had in it somewhat ofdisappointment, said:

"No; there's nothing there now. But I did see something. "

"Are you sure?" asked Ned. 

"Positive!" asserted the other. 

"Well, whatever it was--some bit of machinery he was moving, Ifancy--Tom has taken it in now, " remarked Ned. "Better not sayanything about this, Harry. Tom mightn't like it known. "

"No, I won't. "

"And don't come here again to look. I know you like to see strangethings, but if you'll wait I'll ask Tom, as soon as it's ready, to letyou have a closer view of whatever it was you saw. Better keep awayfrom this tree. "

"I will, " promised the younger lad. "But I'd like to know what itwas--if it really was a giant elephant Say! if a fellow had a troop ofthem he could have a lot of fun with 'em, couldn't he?"

"How?" asked Ned, hardly conscious of what his companion was saying. 

"Why, he could dress 'em up in coats of mail, like the old knights usedto wear, and turn 'em loose against the Germans. Think of a regiment ofelephants, wearin' armor plates like a battleship, carryin' on theirbacks a lot of soldiers with machine guns and chargin' against Fritz!Cracky, that would be a sight!"

"I should say so!" agreed Ned, with a laugh. "There's nothing thematter with your imagination, Harry, my boy!"

"And maybe that's what Tom's doin'!"

"What do you mean?"

"I mean maybe he is trainin' elephants to fight in the war. You know hemade an aerial warship, so why couldn't he have a lot of armor platedelephants?"

"Oh, I suppose he could if he wanted to, " admitted Ned. "But I guesshe isn't doing that. Don't get to going too fast in high speed, Harry, or you may have nightmare. Well, I'm going down to see Tom. "

"And you won't tell him I was peekin'?"

"Not if you don't do it again. I'll advise him to have that tree cutdown, though. It's too good a vantage spot. "

Harry turned and went in the direction of his home, while Ned kept ondown the hill toward the house of his chum. The young bond salesman wasthinking of many things as he tramped, along, and among them was theinformation Harry had just given. 

But Ned did not pay a visit to his chum that evening. When he reachedthe house he found that Tom had gone out, leaving no word as to when hewould be back. 

"Oh, well, I can tell him to-morrow, " thought Ned. 

It was not, however, until two days later that Ned found the time tovisit Tom again. On this occasion, as before, he took the road throughthe clump of woods where he had seen Harry running. 

"And while I'm about it, " mused Ned, "I may as well go on to the placewhere the tree stands and make sure, by daylight, what I only partiallysurmised in the evening--that Tom's place can be looked down on fromthat vantage point. "

Sauntering slowly along, for he was in no special hurry, having theremainder of the day to himself, Ned approached the hill where the treestood from which Harry had said he had seen what he took to be a giantelephant, perhaps in armor. 

"It's a good clear day, " observed Ned, "and fine for seeing. I wonderif I'll be able to see anything. "

It was necessary first to ascend the hill to a point where it overhung, in a measure, the Swift property, though the holdings of Tom and hisfather were some distance beyond the eminence. The tree from which Nedand Harry had made their observations was on a knob of the hill, thestunted pine standing out from among others like it. 

"Well, here goes for another torn coat, " grimly observed Ned, as heprepared to climb. "But I'll be more careful. First, though, let's seeif I can see anything without getting up. "

He paused a little way from the pine, and peered down the hill. Nothingcould be seen of the big enclosed field back of the building aboutwhich Tom Was so careful. 

"You have to be up to see anything, " mused Ned. "It's up a tree for me!Well, here goes!"

As Ned started to work his way up among the thick, green branches, hebecame aware, suddenly and somewhat to his surprise, that he was notthe only person who knew about the observation spot. For Ned saw, ayard above his head, as he started to climb, two feet, encased inwell-made boots, standing on a limb near the trunk of the tree. 

"Oh, ho!" mused Ned. "Some one here before me! Where there are feetthere must be legs, and where there are legs, most likely a body. Andit isn't Harry, either! The feet are too big for that. I wonder--"

But Ned's musings were suddenly cut short, for the person up the treeahead of him moved quickly and stepped on Ned's fingers, with no lighttread. 

"Ouch!" exclaimed the young bank clerk involuntarily, and, letting gohis hold of the limb, he dropped to the ground, while there came astartled exclamation from the screen of pine branches above him. 

Chapter VIII

Detective Rad

"Who's there?" came the demand from the unseen person in the tree. 

"I might ask you the same thing, " was Ned's sharp retort, as he nursedhis skinned and bruised fingers. "What are you doing up there?"

There was no answer, but a sound among the branches indicated that theperson up the tree was coming down. In another moment a man leaped tothe ground lightly and stood beside Ned. The lad observed that thestranger was clean shaven, except for a small moustache which curled upat the ends slightly. 

"For all the world like a small edition of the Kaiser's, " Ned describedit afterward. 

"What are you doing here?" demanded the man, and his voice had in itthe ring of authority. It was this very quality that made Ned bristleup and "get on his ear, " as he said later. The young clerk did notobject to being spoken to authoritatively by those who had the right, but from a stranger it was different. 

"I might ask you the same thing, " retorted Ned. "I have as much righthere as you, I fancy, and I can climb trees, too, but I don't care tohave my fingers stepped on, " and he looked at the scarified members ofhis left hand. 

"I beg your pardon. I'm sorry if I hurt you. I didn't mean to. And ofcourse this is a public place, in a way, and you have a right here. Iwas just climbing the tree to--er--to get a fishing pole!"

Ned had all he could do to keep from laughing. The idea of getting afishing pole from a gnarled and stunted pine struck him as beingaltogether novel and absurd. Yet it was not time to make fun of theman. The latter looked too serious for that. 

"Rather a good view to be had from up where you were, eh?" asked Nedsuggestively. 

"A good view?" exclaimed the other. "I don't know what you mean!"

"Oh, then you didn't see anything, " Ned went on. "Perhaps it's just aswell. Are you fond of fishing?"

"Very. I have--But I forget, I do not know you nor you me. Allow me tointroduce myself. I am Mr. Walter Simpson, and I am here on a visit Ijust happened to walk out this way, and, seeing a small stream, thoughtI should like to fish. I usually carry lines and hooks, and all Ineeded was the pole. I was looking for it when I heard you, and--"

"I felt you!" interrupted Ned, with a short laugh. He told his ownname, but that was all, and seemed about to pass on. 

"Are there any locomotive shops around here?" asked Mr. Simpson. 

"Locomotive shops?" queried Ned. "None that I know of. Why?"

"Well, I heard heavy machinery being used down there;" and he waved hishand toward Tom's shops, "and I thought--"

"Oh, you mean Shopton!" exclaimed Ned. "That's the Swift plant. No, they don't make locomotives, though they could if they wanted to, forthey turn out airships, submarines, tunnel diggers, and I don't knowwhat. "

"Do they make munitions there--for the Allies?" asked Mr. Simpson, andthere was an eager look on his face. 

"No, I don't believe so, " Ned answered; "though, in fact, I don't knowenough of the place to be in a position to give you any informationabout it, " he told the man, not deeming it wise to go into particulars. 

Perhaps the man felt this, as he did not press for an answer. 

The two stood looking at one another for some little time, and then theman, with a bow that had in it something of insolence, as well aspoliteness, turned and went down the path up which Ned had come. 

The young bank clerk waited a little while, and then turned hisattention to the tree which seemed to have suddenly assumed animportance altogether out of proportion to its size. 

"Well, since I'm here I'll have a look up that tree, " decided Ned. 

Favoring his bruised hand, Ned essayed the ascent of the tree moresuccessfully this time. As he rose up among the branches he found hecould look down directly into the yard with the high fence about it. HeCould see only a portion, good as his vantage point was, and thatportion had in it a few workmen--nothing else. 

"No elephants there, " said Ned, with a smile, as he remembered Harry'sexcitement. "Still it's just as well for Tom to know that his place canbe looked down on. I'll go and tell him. "

As Ned descended the tree he caught a glimpse, off to one side amongsome bushes, of something moving. 

"I wonder if that's my Simp friend, playing I spy?" mused Ned. "GuessI'd better have a look. "

He worked his way carefully close to the spot where he had seen themovement. Proceeding then with more caution, watching each step andparting the bushes with a careful hand, Ned beheld what he expected. 

There was the late occupant of the pine tree the man who had stepped onNed's fingers, applying a small telescope to his eye and gazing in thedirection of Tom Swift's home. 

The man stood concealed in a screen of bushes with his back toward Ned, and seemed oblivious to his surroundings. He moved the glass to andfro, and seemed eagerly intent on discovering something. 

"Though what he can see of Tom's place from there isn't much, " musedNed. "I've tried it myself, and I know; you have to be on an elevationto look down. Still it shows he's after something, all right. GuessI'll throw a little scare into him. "

As yet, Ned believed himself unobserved, and that his presence was notsuspected was proved a moment later when he shouted:

"Hey! What are you doing there?"

He had his eye on the partially concealed man, and the latter, as Nedsaid afterward, jumped fully two feet in the air, dropping histelescope as he did so, and turning to face the lad. 

"Oh, it's you, is it?" he faltered. 

"No one else;" and Ned grinned. "Looking for a good place to fish, Ipresume?"

Then, at least for once, the man's suave manner dropped from him as ifit had been a mask. He bared his teeth in a snarl as he answered:

"Mind your own business!"

"Something I'd advise you also to do, " replied Ned smoothly. "You can'tsee anything from there, " he went on. "Better go back to the treeand--cut a fishing pole!"

With this parting shot Ned sauntered down the hill, and swung around tomake his way toward Tom's home. He paid no further attention to theman, save to determine, by listening, that the fellow was searchingamong the bushes for the dropped telescope. 

The young inventor was at home, taking a hasty lunch which Mrs. Baggerthad set out for him, the while he poured over some blueprint drawingsthat, to Ned's unaccustomed eyes, looked like the mazes of someintricate puzzle. 

"Well, where have you been keeping yourself, old man?" asked Tom Swift, after he had greeted his friend. 

"I might ask the same of you, " retorted Ned, with a smile. "I've beentrying to find you to give you some important information, and I madeup my mind, after what happened to-day, to write it and leave it foryou if I didn't see you. "

"What happened to-day?" asked Tom, and there was a serious look on hisface. 

"You are being spied upon--at least, that part of your works enclosedin the new fence is, " replied Ned. 

"You don't mean it!" Cried Tom. "This accounts for some of it, then. "

"For some of what?" asked Ned. 

"For some of the actions of that Blakeson, He's been hanging aroundhere, I understand, asking too many questions about things that I'mtrying to keep secret--even from my best friends, " and as Tom said thisNed fancied there was a note of regret in his voice. 

"Yes, you are keeping some things secret, Tom, " said Ned, determined"to take the bull by the horns, " as it were. 

"I'm sorry, but it has to be, " went on Tom. "In a little while--"

"Oh, don't think that I'm at all anxious to know things!" broke in Ned. "I was thinking of some one else, Tom--another of your friends. "

"Do you mean Mary?"

Ned nodded. 

"She feels rather keenly your lack of explanations, " went on the youngbank clerk. "If you could only give her a hint--"

"I'm sorry, but it can't be done, " and Tom spoke firmly. "But youhaven't told me all that happened. You say I am being spied upon. "

"Yes, " and Ned related what had taken place in the tree. 

"Whew!" whistled Tom. "That's going some with a vengeance! I must havethat tree down in a jiffy. I didn't imagine there was a spot where theyard could be overlooked. But I evidently skipped that tree. Fortunately it's on land owned by a concern with which I have someconnection, and I can have it chopped down without any trouble. Muchobliged to you, Ned. I shan't forget this in a hurry. I'll go rightaway and--"

Tom's further remark was interrupted by the hurried entrance ofEradicate Sampson. The old man was smiling in pleased anticipation, evidently, at the same time, trying hard not to give way to too muchemotion. 

"I's done it, Massa Tom!" he cried exultingly. 

"Done what?" asked the young inventor. "I hope you and Koku haven't hadanother row. "

"No, sah! I don't want nuffin t' do wif dat ornery, low-down whitetrash! But I's gone an' done whut I said I'd do!"

"What's that, Rad? Come on, tell us! Don't keep us in suspense. "

"I's done some deteckertiff wuk, lest laik I said I'd do, an' I'scotched him! By golly, Massa Tom! I's cotched him black-handed, as itsays!"

"Caught him? Whom have you caught, Rad?" cried Tom. "Do you suppose hemeans he's caught the man you saw up the tree, Ned? The man you thinkis a German spy?"

"It couldn't be. I left him only a little while ago hunting for histelescope. "

"Then whom have you caught, Rad?" cried Tom. "Come on, I'll give youcredit for it. Tell us!"

"I's cotched dat Dutch Sauerkrauter, dat's who I's cotched, Massa Tom!By golly, I's cotched him!"

"But who, Rad? Who is he?"

"I don't know his name, Massa Tom, but he's a Sauerkrauter, all right. Dat's whut he eats for lunch, an' dat's why I calls him dat. I'scotched him, an' he's locked up in de stable wif mah mule Boomerang. An' ef he tries t' git out Boomerang'll jest natchully kick him intolittle pieces--dat's whut Boomerang will do, by golly!"

Chapter IX

A Night Test

"Come on, Ned, " said Tom, after a moment or two of silent contemplationof Eradicate. "I don't know what this cheerful camouflager of mine istalking about, but we'll have to go to see, I suppose. You say you haveshut some one up in Boomerang's stable, Rad?"

"Yes, sah, Massa Tom, dat's whut I's gone an done. "

"And you say he's a German?"

"I don't know as to dat, Massa Tom, but he suah done eat sauerkraut'mostest ebery meal. Dat's whut I call him--a Sauerkrauter! An' he suahwas spyin'. "

"How do you know that, Rad?"

"'Cause he done went from his own shop on annuder man's ticket into desecret shop, dat's whut he went an' done!"

"Do you mean to tell me, Rad, " went on Tom, "that one of the workmenfrom another shop entered Number Thirteen on the pass issued in thename of one of the men regularly employed in my new shop?"

"Dat's whut he done, Massa Tom. "

"How do you know?"

"'Cause I detected him doin' it. Yo'-all done made me a deteckertiff, an' I detected. "

"Go on, Rad. "

"Well, sah, Massa Tom, I seen dish yeah Dutchman git a ticket-passoffen one ob de reg'lar men. Den he went in de unlucky place an' stayedfo' a long time. When he come out I jest natchully nabbed him, dat'swhut I done, an' I took him to Boomerang's stable. "

"How'd you get him to go with you?" asked Ned, for the old colored manwas feeble, and most of the men employed at Tom's plant were of arobust type. 

"I done fooled him. I said as how I'd lest brought from town in mahmule cart some new sauerkraut, an' he could sample it if he liked. Sohe went wif me, an' when I got him to de stable I pushed him in andlocked de door!"

"Come on!" cried Tom to his chum. "Rad may be right, after all, and oneof my workmen may be a German spy, though I've tried to weed them allout. 

"However, no matter about that, if he was employed in another shop, hehad no right to go into Number Thirteen. That's a violation of rules. But if he's in Rad's ramshackle stable he can easily get out. "

"No, sah, dat's whut he can't do!" insisted the colored man. 

"Why not?" asked Tom. 

"'Cause Boomerang's on guard, an' yo'-all knows how dat mule of minecan use his heels!"

"I know, Rad, " went on Tom; "but this fellow will find a way of keepingout of their way. We must hurry. "

"Oh, he's safe enough, " declared the colored man. "I done tole Koku tostan' guard, too! Dat low-down white trash ob a giant is all right fo'guardin', but he ain't wuff shucks at detectin'!" said Eradicate, withpardonable pride. "By golly, maybe I's too old t' put on guard, but Ikin detect, all right!"

"If this proves true, I'll begin to believe you can, " replied Tom. "Hopalong, Ned!"

Followed by the shuffling and chuckling negro, Tom and Ned went to therather insecure stable where the mule Boomerang was kept. That is, thestable was insecure from the standpoint of a jail. But the sight of thegiant Koku marching up and down in front of the place, armed with a bigclub, reassured Tom. 

"Is he in there, Koku?" asked the young inventor. 

"Yes, Master! He try once come out, but he approach his head very closemy defense weapon and he go back again. "

"I should think he would, " laughed Ned, as he noted the giant's club. 

"Well, Rad, let's have a look at your prisoner. Open the door, Koku, "commanded Tom. 

"Better look out, " advised Ned. "He may be armed. "

"We'll have to take a chance. Besides, I don't believe he is, or he'dhave fired at Koku. There isn't much to fear with the giant ready foremergencies. Now we'll see who he is. I can't imagine one of my menturning traitor. "

The door was opened and a rather miserable-looking man shuffled out. There was a bloody rag on his head, and he seemed to have made more ofan effort to escape than Koku described, for he appeared to havesuffered in the ensuing fight. 

"Carl Schwen!" exclaimed Tom. "So it was you, was it?"

The German, for such he was, did not answer for a moment He appeareddowncast, and as if suffering. Then a change came over him. Hestraightened up, saluted as a soldier might have done, and a sneeringlook came into his face. It was succeeded by one of pride as the manexclaimed:

"Yes, it is I! And I tried to do what I tried to do for the Fatherland!I have failed. Now you will have me shot as a spy, I suppose!" he addedbitterly. 

Tom did not answer directly. He looked keenly at the man, and at lastsaid:

"I am sorry to see this. I knew you were a German, Schwen, but I keptyou employed at work that could not, by any possibility, be consideredas used against your country. You are a good machinist, and I neededyou. But if what I hear about you is true, it is the end. "

"It is the end, " said the man simply. "I tried and failed. If it hadnot been for Eradicate--Well, he's smarter than I gave him credit for, that's all!"

The man spoke very good English, with hardly a trace of German accent, but there was no doubt as to his character. 

"What will you do with him, Tom?" asked Ned. 

"I don't know. I'll have to do a little investigating first. But hemust be locked up. Schwen, " went on the young inventor, "I'm sorryabout this, but I shall have to give you into the custody of a UnitedStates marshal. You are not a naturalized citizen, are you?"

The man muttered something in German to the effect that he was notnaturalized and was glad of it. 

"Then you come under the head of an enemy alien, " decided Tom, whounderstood what was said, "and will have to be interned. I had hoped toavoid this, but it seems it cannot be. I am sorry to lose you, butthere are more important matters. Now let's get at the bottom of this. "

Schwen was, after a little delay, taken in charge by the properofficer, and then a search was made of his room, for, in common withsome of the other workmen, he lived in a boarding house not far fromthe plant. 

There, by a perusal of his papers, enough was revealed to show Tom thedanger he had escaped. 

"And yet I don't know that I have altogether escaped it, " he said toNed, as they talked it over. "There's no telling how long this spy workmay have been going on. If he has discovered all the secrets of ShopThirteen it may be a bad thing for the Allies and--"

"Look out!" warned Ned, with a laugh. "You'll be saying things youdon't want to, Tom and not at all in keeping with your former silence. "

"That's so, " agreed the young inventor, with a sigh. "But if things goright I'll not have to keep silent much longer. I may be able to tellyou everything. "

"Don't tell me--tell Mary, " advised his chum. "She feels your silencemore than I do. I know how such things are. "

"Well, I'll be able to tell her, too, " decided Tom. "That is, if Schwenhasn't spoiled everything. Look here, Ned, these papers show he's beenin correspondence with Blakeson and Grinder. "

"What about, Tom?"

"I can't tell. The letters are evidently written in code, and I can'ttranslate it offhand. But I'll make another attempt at it. And here'sone from a person who signs himself Walter Simpson, but the writing isin German. "

"Walter Simpson!" cried Ned. "That's my friend of the tree!"

"It is?" cried Tom. "Then things begin to fit themselves together. Simpson is a spy, and he was probably trying to communicate withSchwen. But the latter didn't get the information he wanted, or, if hedid get it, he wasn't able to pass it on to the man in the tree. Eradicate nipped him just in time. "

And, so it seemed, the colored man had done. By accident he haddiscovered that Schwen had prevailed on one of the workmen in Shop 13to change passes with him. This enabled the German spy to gainadmittance to the secret place, which Tom thought was so well guarded. The man who let Schwen take the pass was in the game, too, it appeared, and he was also placed under arrest. But he was a mere tool in the payof the others, and had no chance to gain valuable information. 

A hasty search of Shop 13 did not reveal anything missing, and it wassurmised (for Schwen would not talk) that he had not found time to goabout and get all that he was after. 

Soon after Schwen's arrest the "Spy Tree, " as Tom called it, was cutdown. 

"Eradicate certainly did better than I ever expected he would, "declared Tom. "Well, if all goes well, there won't be so much need forsecrecy after a day or so. We're going to give her a test, and then--"

"Give who a test?" asked Ned, with a smile. 

"You'll soon see, " answered Tom, with an answering grin. "I herebyinvite you and Mr. Damon to come over to Shop Thirteen day afterto-morrow night and then--Well, you'll see what you'll see. "

With this Ned had to be content, and he waited anxiously for theappointed time to come. 

"I surely will be glad when Tom is more like himself, " he mused, as heleft his chum. "And I guess Mary will be, too. I wonder if he's goingto ask her to the exhibition?"

It developed that Tom had done so, a fact which Ned learned on themorning of the day set for the test. 

"Come over about nine o'clock, " Tom said to his chum. "I guess it willbe dark enough then. "

Meanwhile Schwen and Otto Kuhn, the other man involved, had been lockedup, and all their papers given into the charge of the United Statesauthorities. A closer guard than ever was kept over No. 13 shop, andsome of the workmen, against whom there was a slight suspicion, weretransferred. 

"Well, we'll see what we shall see, " mused Ned on the appointedevening, when a telephone message from Mr. Damon informed the youngbank clerk that the eccentric man was coming to call for him beforegoing on to the Swift place. 

Chapter X

A Runaway Giant

"What do you think it's all about, Mr. Damon?"

"I'm sure I don't know, Ned. "

The two were at the home of the young bank clerk, preparing to startfor the Swift place, it being nearly nine o'clock on the evening namedby the youthful inventor. 

"Bless my hat-rack!" went on the eccentric man, "but Tom isn't at alllike himself of late. He's working on some invention, I know that, butit's all I do know. He hasn't given me a hint of it. "

"Nor me, nor any of his friends, " added Ned. "And he acts so oddlyabout enlisting--doesn't want even to speak of it. How he got exemptedI don't know, but I do know one thing, and that is Tom Swift is forUncle Sam first, last and always!"

"Oh, of course!" agreed Mr. Damon. "Well, we'll soon know, I guess. We'd better start, Ned. "

"It's useless to try to guess what it is Tom is up to. He has kept hissecret well. The nearest any one has come to it was when Harry figuredout that Tom had a band of giant elephants which he was fitting withcoats of steel armor to go against the Germans, " observed Ned, when heand Mr. Damon were on their way. 

"Well, that mightn't be so bad, " agreed Mr. Damon. "But--um--elephants--and wild giant ones, too! Bless my circus ticket, Ned! do you think we'd better go in that case?"

"Oh, Tom hasn't anything like that!" laughed Ned. "That was onlyHarry's crazy notion after he saw something big and ungainly careeningabout the enclosed yard of Shop Thirteen. Hello, there go Mary Nestorand her father!" and Ned pointed to the opposite side of the streetwhere the girl and Mr. Nestor could be seen in the light of a streetlamp. 

"They're going out to see Tom's secret, " said Mr. Damon. "There'splenty of room in my car. Let's ask them to go with us. "

"Surely, " agreed Ned, and a moment later he and Mary were in the rearseat while Mr. Damon and Mr. Nestor were in the front, Mr. Damon at thewheel, and they were soon speeding down the road. 

"I do hope everything will go all right, " observed Mary. 

"What do you mean?" asked Ned. 

"I mean Tom is a little bit anxious about this test. "

"Did he tell you what it was to be?"

"No; but when he called to invite father and me to be present he seemedworried. I guess it's a big thing, for he never has acted this waybefore--not talking about his work. "

"That's right, " assented Ned. "But the secret will soon be disclosed, Ifancy. But how is it you aren't going to the dance with LieutenantMartin? He told me you had half accepted for to-night. "

"I had. " And if it had been light enough Ned would have seen Maryblushing. "I was going with him. It's a dance for the benefit of theRed Cross to get money for comfort kits for the soldiers. But when Tomsent word that he'd like to have me present to-night, why--"

"Oh, I see!" broke in Ned, with a little laugh. "'Nough said!"

Mary's blushes were deeper, but the kindly night hid them. 

Then they conversed on matters connected with the big war--the sellingof Liberty Bonds, the Red Cross work and the Surgical DressingsCommittee, in which Mary was the head of a junior league. 

"Everybody in Shopton seems to be doing something to help win the war, "said Mary, and as there was just then a lull in the talk between herfather and Mr. Damon her words sounded clearly. 

"Yes, everybody--that is, all but a few, " said Mr. Nestor, "and theyought to get busy. There are some young fellows in this town that oughtto be wearing khaki, and I don't mean you, Ned Newton. You're doingyour bit, all right. "

"And so is Tom Swift!" exclaimed Mr. Damon, as if there had been animplied accusation against the young inventor. "I heard, only to-day, that one of his inventions--a gas helmet that he planned--is in use onthe Western front in Europe. Tom gave his patents to the government, and even made a lot of the helmets free to show other factories how toturn them out to advantage. "

"He did?" cried Mr. Nestor. 

"That's what he did. Talk about doing your bit--"

"I didn't know that, " observed Mary's father slowly. "Do you supposeit's a test of another gas helmet that Tom has asked us out to seeto-night?"

"I hardly think so, " said Ned. "He wouldn't wait until after dark forthat This is something big, and Tom must intend to have it out in theopen. He probably waited until after sunset so the neighbors wouldn'tcome out in flocks. There's been a lot of talk about what is going onin Shop Thirteen, especially since the arrest of the German spies, andthe least hint that a test is under way would bring out a big crowd. "

"I suppose so, " agreed Mr. Nestor. "Well, I'm glad to know that Tom isdoing something for Uncle Sam, even if it's only helping with gashelmets. Those Germans are barbarians, if ever there were any, andwe've got to fight them the same way they fight us! That's the only wayto end the war! Now if I had my way, I'd take every German I could laymy hands on--"

"Father, pretzels!" exclaimed Mary. 

"Eh? What's that, my dear?"

"I said pretzels!"

"Oh!" and Mr. Nestor's voice lost its sharpness. 

"That's my way of quieting father down when he gets too strenuous inhis talk about the war, " explained Mary. "We agreed that whenever hegot excited I was to say 'pretzels' to him, and that would make himremember. We made up our little scheme after he got into an argumentwith a man on the train and was carried past his station. "

"That's right, " admitted Mr. Nestor, with a laugh. "But that fellow wasthe most obstinate, pig-headed Dutchman that ever tackled a plate ofpig's knuckles and sauerkraut, and if he had the least grain of commonsense he'd--"

"Pretzels!" cried Mary. 

"Eh? Oh, yes, my dear. I was forgetting again. "

There was a moment of merriment, and then, after the talk had run for awhile in other and safer channels, Mr. Damon made the announcement:

"I think we're about there. We'll be at Tom's place when we make theturn and--"

He was interrupted by a low, heavy rumbling. 

"What's that?" asked Mr. Nestor. 

"It's getting louder--the noise, " remarked Mary. "It sounds as if somebig body were approaching down the road--the tramp of many feet. Can itbe that troops are marching away?"

"Bless my spark plug!" suddenly cried Mr. Damon. "Look!"

They gazed ahead, and there, seen in the glare of the automobileheadlights, was an immense, dark body approaching them from across alevel field. The rumble and roar became more pronounced and the groundshook as though from an earthquake. 

A glaring light shone out from the ponderous moving body, and above theroar and rattle a voice called:

"Out out of the way! We've lost control! Look out!"

"Bless my steering wheel!" gasped Mr. Damon, "that was Tom Swift'svoice! But what is he doing in that--thing?"

"It must be his new invention!" exclaimed Ned. 

"What is it?" asked Mr. Nestor. 

"A giant, " ventured Ned. "It's a giant machine of some sort and--"

"And it's running away!" cried Mr. Damon, as he quickly steered his carto one side--and not a moment too soon! An instant later in a cloud ofdust, and with a rumble and a roar as of a dozen express trains fusedinto one, the runaway giant--of what nature they could onlyguess--flashed and lumbered by, Tom Swift leaning from an opening inthe thick steel side, and shouting something to his friends. 

Chapter XI

Tom's Tank

"What was it?" gasped Mary, and, to her surprise, she found herselfclose to Ned, clutching his arm. 

"I have an idea, but I'd rather let Tom tell you, " he answered. 

"But where's it going?" asked Mr. Nestor. "What in the world does TomSwift mean by inviting us out here to witness a test, and then nearlyrunning us down under a Juggernaut?"

"Oh, there must be some mistake, I'm sure, " returned his daughter. "Tomdidn't intend this. "

"But, bless my insurance policy, look at that thing go! What in theworld is it?" cried Mr. Damon. 

The "thing" was certainly going. It had careened from the road, tilteditself down into a ditch and gone on across the fields, lights shootingfrom it in eccentric fashion. 

"Maybe we'd better take after it, " suggested Mr. Nestor. "If Tom is--"

"There, it's stopping!" cried Ned. "Come on!"

He sprang from the automobile, helped Mary to get out, and then thetwo, followed by Mr. Damon and Mr. Nestor, made their way across thefields toward the big object where it had come to a stop, the rumblingand roaring ceasing. 

Before the little party reached the strange machine--the "runawaygiant, " as they dubbed it in their excitement--a bright light flashedfrom it, a light that illuminated their path right up to the monster. And in the glare of this light they saw Tom Swift stepping out througha steel door in the side of the affair. 

"Are you all right?" he called to his friends, as they approached. 

"All right, as nearly as we can be when we've been almost scared todeath, Tom, " said Mr. Nestor. 

"I'm surely sorry for what happened, " Tom answered, with a relievedlaugh. "Part of the steering gear broke and I had to guide it byoperating the two motors alternately. It can be worked that way, but ittakes a little practice to become expert. "

"I should say so!" cried Mr. Damon. "But what in the world does it allmean, Tom Swift? You invite us out to see something--"

"And there she is!" interrupted the young inventor. "You saw her alittle before I meant you to, and not under exactly the circumstances Ihad planned. But there she is!" And he turned as though introducing themetallic monster to his friends. 

"What is she, Tom?" asked Ned. "Name it!"

"My latest invention, or rather the invention of my father and myself, "answered Tom, and his voice showed the love and reverence he felt forhis parent. "Perhaps I should say adaptation instead of invention, " Tomwent on, "since that is what it is. But, at any rate, it's mylatest--dad's and mine--and it's the newest, biggest, most improved andpowerful fighting tank that's been turned out of any shop, as far as Ican learn. 

"Ladies--I mean lady and gentlemen--allow me to present to you War TankA, and may she rumble till the pride of the Boche is brought low andhumble!" cried Tom. 

"Hurray! That's what I say!" cheered Ned. 

"That's what I have been at work on lately. I'll give you a littlehistory of it, and then you may come inside and have a ride home. "

"In that?" cried Mr. Damon. 

"Yes. I can't promise to move as speedily as your car, but I can makebetter time than the British tanks. They go about six miles an hour, Iunderstand, and I've got mine geared to ten. That's one improvement dadand I have made. "

"Ride in that!" cried Mr. Nestor. "Tom, I like you, and I'm glad to seeI've been mistaken about you. You have been doing your bit, after all;but--"

"Oh, I've only begun!" laughed Tom Swift. 

"Well, no matter about that. However much I like you, " went on Mr. Nestor, "I'd as soon ride on the wings of a thunderbolt as in Tank A, Tom Swift. "

"Oh, it isn't as bad as that!" laughed the young scientist. "Butneither is it a limousine. However, come inside, anyhow, and I'll tellyou something about it. Then I guess we can guide it back. The men arerepairing the break. "

The visitors entered the great craft through the door by which Tom hademerged. At first all they saw was a small compartment, with walls ofheavy steel, some shelves of the same and a seat which folded upagainst the wall made of like powerful material. 

"This is supposed to be the captain's room, where he stays when hedirects matters. " Tom explained. "The machinery is below and beyondhere. "

"How'd you come to evolve this?" asked Ned. "I haven't seen half enoughof the outside, to say nothing of the inside. "

"You'll have time enough, " Tom said. "This is my first completed tank. There are some improvements to be made before we send it to the otherside to be copied. 

"Then they'll make them in England as well as here, and from here we'llship them in sections. "

"I don't see how you ever thought of it!" exclaimed the girl, in wonder. 

"Well, I didn't all at once, " Tom answered, with a laugh. "It came bydegrees. I first got the idea when I heard of the British tanks. 

"When I had read how they went into action and what they accomplishedagainst the barbed wire entanglements, and how they crossed thetrenches, I concluded that a bigger tank, one capable of more speed, say ten or twelve miles an hour, and one that could cross biggerexcavations--the English tanks up to this time can cross a ditch oftwelve feet--I thought that, with one made on such specifications, moreeffective work could be done against the Germans. "

"And will yours do that?" asked Ned. "I mean will it do ten miles anhour, and straddle over a wider ditch than twelve feet?"

"It'll do both, " promptly answered Tom. "We did a little better thaneleven miles an hour a while ago when I yelled to you to get out of theway just now. It's true we weren't under good control, but the speedhad nothing to do with that. And as for going over a big ditch, I thinkwe straddled one about fourteen feet across back there, and we can dobetter when I get my grippers to working. "

"Grippers!" exclaimed Mary. 

"What kind of trench slang is that, Tom Swift?" asked Mr. Damon. 

"Well, that's a new idea I'm going to try out It's something likethis, " and while from a distant part of the interior of Tank A came thesound of hammering, the young inventor rapidly drew a rough pencilsketch. 

It showed the tank in outline, much as appear the pictures of tanksalready in service--the former simile of two wedge-shaped pieces ofmetal put together broad end to broad end, still holding good. From oneend of the tank, as Tom drew it, there extended two long arms oflatticed steel construction. 

"The idea is, " said Tom, "to lay these down in front of the tank, bymeans of cams and levers operated from inside. If we get to a ditchwhich we can't climb down into and out again, or bridge with the beltcaterpillar wheels, we'll use the grippers. They'll be laid down, taking a grip on the far side of the trench, and we'll slide across onthem. "

"And leave them there?" asked Mr. Damon. 

"No, we won't leave them. We'll pick them up after we have passed overthem and use them in front again as we need them. A couple of extrapairs of grippers may be carried for emergencies, but I plan to use thesame ones over and over again. "

"But what makes it go?" asked Mary. "I don't want all the details, Tom, " she said, with a smile, "but I'd like to know what makes yourtank move. "

"I'll be able to show you in a little while, " he answered. "But it maybe enough now if I tell you that the main power consists of two biggasolene engines, one on either side. They can be geared to operatetogether or separately. And these engines turn the endless belts madeof broad, steel plates, on which the tank travels. The belts pass alongthe outer edges of the tank longitudinally, and go around cogged wheelsat either end of the blunt noses. 

"When both belts travel at the same rate of speed the tank goes in astraight line, though it can be steered from side to side by means of atrailer wheel in the rear. Making one belt--one set of caterpillarwheels, you know--go faster than the other will make the tank travel toone side or the other, the turn being in the direction of the slowestmoving belt. In this way we can steer when the trailer wheels arebroken. "

"And what does your tank do except travel along, not minding a hail ofbullets?" asked Mr. Nestor. 

"Well, " answered Tom, "it can do anything any other tank can do, andthen some more. It can demolish a good-sized house or heavy wall, breakdown big trees, and chew up barbed-wire fences as if they weretoothpicks. I'll show you all that in due time. Just now, if therepairs are finished, we can get back on the road--"

At that moment a door leading into the compartment where Tom and hisfriends were talking opened, and one of the workmen said:

"A man outside asking to see you, Mr. Swift. "

"Pardon me, but I won't keep you a moment, " interrupted a suave voice. "I happened to observe your tank, and I took the liberty of entering tosee--"

"Simpson!" cried Ned Newton, as he recognized the man who had been upthe tree. "It's that spy, Simpson, Tom!"

Chapter XII

Bridging a Gap

Such surprise showed both on the face of Ned Newton and that of the manwho called himself Walter Simpson that it would be hard to say whichwas in the greater degree. For a moment the newcomer stood as if he hadreceived all electric shock, and was incapable of motion. Then, as theechoes of Ned's voice died away and the young bank clerk, being thefirst to recover from the shock, made a motion toward the unwelcome anduninvited intruder, Simpson exclaimed. 

"I will not bother now. Some other time will do as well. "

Then, with a haste that could be called nothing less than precipitate, he made a turn and fairly shot out of the door by which he had enteredthe tank. 

"There he goes!" cried Mr. Damon. "Bless my speedometer, but there hegoes!"

"I'll stop him!" cried Ned. "We've got to find out more about him! I'llget him, Tom!"

Tom Swift was not one to let a friend rush alone into what might bedanger. He realized immediately what his chum meant when he called outthe identity of the intruder, and, wishing to clear up some of themystery of which he became aware when Schwen was arrested and the papershowing a correspondence with this Simpson were found, Tom darted outto try to assist in the capture. 

"He went this way!" cried Ned, who was visible in the glare of thesearchlight that still played its powerful beams over the stern of thetank, if such an ungainly machine can be said to have a bow and stern. "Over this way!"

"I'm with you!" cried Tom. "See if you can pick up that man who justran out of here!" he cried to the operator of the searchlight in theelevated observation section of what corresponded to the conning towerof a submarine. This was a sort of lookout box on top of the tank, containing, among other machines, the searchlight. "Pick him up!" criedTom. 

The operator flashed the intense white beam, like a finger of light, around in eccentric circles, but though this brought into vivid reliefthe configuration of the field and road near which the tank wasstalled, it showed no running fugitive. Tom and Ned wereobserved--shadows of black in the glare--by Mary and her friends in thetank, but there was no one else. 

"Come on!" cried Ned. "We can find him, Tom!"

But this was easier said than done. Even though they were aided by thebright light, they caught no glimpse of the man who called himselfSimpson. 

"Guess he got away, " said Tom, when he and Ned had circled about andinvestigated many clumps of bushes, trees, stumps and other barriersthat might conceal the fugitive. 

"I guess so, " agreed Ned. "Unless he's hiding in what we might call ashell crater. "

"Hardly that, " and Tom smiled. "Though if all goes well the men whooperate this tank later may be searching for men in real shell holes. "

"Is this one going to the other side?" asked Ned, as the two walkedback toward the tank. 

"I hope it will be the first of my new machines on the Western front, "Tom answered. "But I've still got to perfect it in some details andthen take it apart. After that, if it comes up to expectations, we'llbegin making them in quantities. "

"Did you get him?" asked Mr. Damon eagerly, as the two young men cameback to join Mary and her friends. 

"No, he got away, " Tom answered. 

"Did he try to blow up the tank?" asked Mr. Nestor, who had an abnormalfear of explosives. "Was he a German spy?"

"I think he's that, all right, " said Ned grimly. "As to his endeavoringto blow up Tom's tank, I believe him capable of it, though he didn'ttry it to-night--unless he's planted a time bomb somewhere about, Tom. "

"Hardly, I guess, " answered the young inventor. "He didn't have achance to do that. Anyhow we won't remain here long. Now, Ned, whatabout this chap? Is he really the one you saw up in the tree?"

"I not only saw him but I felt him, " answered Ned, with a rueful lookat his fingers. "He stepped right on me. And when he came inside thetank to-night I knew him at once. I guess he was as surprised to see meas I was to see him. "

"But what was his object?" asked Mr. Nestor. 

"He must have some connection with my old enemy, Blakeson, " answeredTom, "and we know he's mixed up with Schwen. From the looks of him Ishould say that this Simpson, as he calls himself, is the directinghead of the whole business. He looks to be the moneyed man, and thebrains of the plotters. Blakeson is smart, in a mechanical way, andSchwen is one of the best machinists I've ever employed. But thisSimpson strikes me as being the slick one of the trio. "

"But what made him come here, and what did he want?" asked Mary. "Dearme! it's like one of those moving picture plots, only I never saw onewith a tank in it before--I mean a tank like yours, Tom. "

"Yes, it is a bit like moving picture--especially chasing Simpson bysearchlight, " agreed the young inventor. "As to what he wanted, Isuppose he came to spy out some of my secret inventions--dad's andmine. He's probably been hiding and sneaking around the works eversince we arrested Schwen. Some of my men have reported seeingstrangers about, but I have kept Shop Thirteen well guarded. 

"However, this fellow may have been waiting outside, and he may havefollowed the tank when we started off a little while ago for the nighttest. Then, when he saw our mishap and noticed that we were stalled, hecame in, boldly enough, thinking, I suppose, that, as I had never seenhim, he would take a chance on getting as much information as he couldin a hurry. "

"But he didn't count on Ned's being here!" chuckled Mr. Damon. 

"No; that's where he slipped a cog, " remarked Mr. Nestor. "Well, Tom, I like your tank, what I've seen of her, but it's getting late and Ithink Mary and I had better be getting back home. "

"We'll be ready to start in a little while, " Tom said, after a briefconsultation with one of his men. "Still, perhaps it would be just aswell if you didn't ride back with me. She may go all right, and then, again, she may not. And as it's dark, and we're in a rough part of thefield, you might be a bit shaken up. Not that the tank minds it!" theyoung inventor hastened to add "She's got to do her bit over worseplaces than this--much worse--but I want to get her in a little betterworking shape first. So if you don't mind, Mary, I'll postpone yourinitial trip. "

"Oh, I don't mind, Tom! I'm so glad you've made this! I want to see thewar ended, and I think machines like this will help. "

"I'll ride back with you, Tom, if you don't mind, " put in Ned. "I guessa little shaking up won't hurt me. "

"All right--stick. We're going to start very soon. "

"Well, I'm coming over to-morrow to have a look at it by daylight, "said Mr. Damon, as he started toward his car. 

"So am I, " added Mary. "Please call for me, Mr. Damon. "

"I will, " he promised. 

Mr. Nestor, his daughter, and Mr. Damon went back to the automobile, while Ned remained with Tom. In a little while those in the car heardonce more the rumbling and roaring sound and felt the earth tremble. Then, with a flashing of lights, the big, ungainly shape of the tanklifted herself out of the little ditch in which she had come to a halt, and began to climb back to the road. 

Ned Newton stood beside Tom in the control tower of the great tank asshe started on her homeward way. 

"Isn't it wonderful!" murmured Mary, as she saw Tank A lumbering alongtoward the road. "Oh, and to think that human beings made that To thinkthat Tom should know how to build such a wonderful machine!"

"And run it, too, Mary! That's the point! Make it run!" cried herfather. "I tell you, that Tom Swift is a wonder!"

"Bless my dictionary, he sure is!" agreed Mr. Damon. 

Along the road, back toward the shop whence it had emerged, rumbled thetank. The noise brought to their doors inhabitants along the countrythoroughfare, and some of them were frightened when they saw TomSwift's latest war machine, the details of which they could only guessat in the darkness. 

"She'll butt over a house if it gets in her path, knock down trees, chew up barbed-wire, and climb down into ravines and out again, and goover a good-sized stream without a whimper, " said Tom, as he steeredthe great machine. 

There was little chance then for Ned to see much of the insidemechanism of the tank. He observed that Tom, standing in the forwardtower, steered it very easily by a small wheel or by a lever, alternately, and that he communicated with the engine room by means ofelectric signals. 

"And she steers by electricity, too, " Tom told his friend. "That wasone difficulty with the first tanks. They had to be steered by bruteforce, so to speak, and it was a terrific strain on the man in thetower. Now I can guide this in two ways: by the electric mechanismwhich swings the trailer wheels to either side, or by varying the speedof the two motors that work the caterpillar belts. So if one breaksdown, I have the other. "

"Got any guns aboard her--I mean machine guns?" asked Ned. 

"Not yet. But I'm going to install some. I wanted to get the tank inproper working order first. The guns are only incidental, though ofcourse they're vitally necessary when she goes into action. I've got'em all ready to put in. But first I'm going to try the grippers. "

"Oh, you mean the gap-bridgers?" asked Ned. 

"That's it, " answered Tom. "Look out, we're going over a rough spotnow. "

And they did. Ned was greatly shaken up, and fairly tossed from side toside of the steering tower. For the tank contained no springs, exceptsuch as were installed around the most delicate machinery, and it waslike riding in a dump cart over a very rough road. 

"However, that's part of the game, " Tom observed. 

Tank A reached her "harbor" safely--in other words, the machine shopenclosed by the high fence, inside of which she had been built. 

Tom and Ned made some inquiries of Koku and Eradicate as to whether ornot there had been any unusual sights or sounds about the place. Theyfeared Simpson might have come to the shop to try to get possession ofimportant drawings or data. 

But all had been quiet, Koku reported Nor had Eradicate seen or heardanything out of the ordinary. 

"Then I guess we'll lock up and turn in, " decided Tom. "Come overto-morrow, Ned. "

"I will, " promised the young bank clerk. "I want to see more of whatmakes the wheels go round. " And he laughed at his own ingenuousness. 

The next day Tom showed his friends as much as they cared to see aboutthe workings of the tank. They inspected the powerful gasolene engines, saw how they worked the endless belts made of plates of jointed steel, which, running over sprocket wheels, really gave the tank its power byproviding great tractive force. 

Any self-propelled vehicle depends for its power, either to move itselfor to push or to pull, on its tractive force--that is, the grip it canget on the ground. 

In the case of a bicycle little tractive power is needed, and this isprovided by the rubber tires, which grip the ground. A locomotivedepends for its tractive power on its weight pressing on its drivingwheels, and the more driving wheels there are and the heavier thelocomotive, the more it can pull, though in that case speed is lost. This is why freight locomotives are so heavy and have so many largedriving wheels. They pull the engine along, and the cars also, by theirweight pressing on the rails. 

The endless steel belts of a tank are, the same as the wheels of alocomotive. And the belts, being very broad, which gives them a largesurface with which to press on the ground, and the tank being veryheavy, great power to advance is thus obtained, though at the sacrificeof speed. However, Tom Swift had made his tank so that it would doabout ten miles and more an hour, nearly double the progress obtainedup to that time by the British machines. 

His visitors saw the great motors, they inspected the compact but notvery attractive living quarters of the crew, for provision had to bemade for the men to stay in the tank if, perchance, it became stalledin No Man's Land, surrounded by the enemy. 

The tank was powerfully armored and would be armed. There were a numberof machine guns to be installed, quick-firers of various types, and inaddition the tank could carry a number of riflemen. 

It was upon the crushing power of the tank, though, that most reliancewas placed. Thus it could lead the way for an infantry advance throughthe enemy's lines, making nothing of barbed wire that would take anartillery fire of several days to cut to pieces. 

"And now, Ned, " said Tom, about a week after the night test of thetank, "I'm going to try what she'll do in bridging a gap. "

"Have you got her in shape again?"

"Yes, everything is all right. I've taken out the weak part in thesteering gear that nearly caused us to run you down, and we're safe inthat respect now. And I've got the grippers made. It only remains tosee whether they're strong enough to bear the weight of my littlebaby, " and Tom affectionately patted the steel sides of Tank A. 

While his men were getting the machine ready for a test out on theroad, and for a journey across a small stream not far away, Tom toldhis chum about conceiving the idea for the tank and carrying it outsecretly with the aid of his father and certain workmen. 

"That's the reason the government exempted me from enlisting, " Tomsaid. "They wanted me to finish this tank. I didn't exactly want to, but I considered it my 'bit. ' After this I'm going into the army, Ned. "

"Glad to hear it, old man. Maybe by that time I'll have this LibertyBond work finished, and I'll go with you. We'll have great timestogether! Have you heard anything more of Simpson, Blakeson andScoundrels?" And Ned laughed as he named this "firm. "

"No, " answered Tom. "I guess we scared off that slick German spy. "

Once more the tank lumbered out along the road. It was a mighty engineof war, and inside her rode Tom and Ned. Mary and her father had beeninvited, but the girl could not quite get her courage to the point ofaccepting, nor did Mr. Nestor care to go. Mr. Damon, however, as mightbe guessed, was there. 

"Bless my monkey wrench, Tom!" cried the eccentric man, as he notedtheir advance over some rough ground, "are you really going to makethis machine cross Tinkle Creek on a bridge of steel you carry withyou?"

"I'm going to try, Mr. Damon. "

A little later, after a successful test up and down a small gully, TankA arrived at the edge of Tinkle Creek, a small stream about twenty feetwide, not far from Tom's home. At the point selected for the test thebanks were high and steep. 

"If she bridges that gap she'll do anything, " murmured Ned, as the tankcame to a stop on the edge. 

Chapter XIII

Into a Trench

Tom cast a hasty glance over the mechanism of the machine before hestarted to cross the stream by the additional aid of the grippers, orspanners, 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 peculiartriangular construction, designed to support heavy weights, and eachend was broadly flanged to prevent its sinking too deeply into theearth 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 clawswere designed to grip the earth to prevent slipping. 

The spanners would be pulled out from their sockets on the side of thetank by means of steel cables, which were operated from within. Theywould be run out across the gap and fastened in place. The tank wasdesigned to travel along them to the other side of the gap, and, oncethere, to pick tip 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 ona small model. They worked there, but whether they will work inpractice remains to be seen. Of course, at this stage, I'm willing tostake my all on the results, but there is always a half-question untilthe 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 beensaid, on the very edge of Tinkle Creek. The banks were fairly solidhere, and descended precipitously to the water ten feet below. Theshores were about twenty feet apart. 

"Suppose the spanners break when you're halfway over, Tom?" asked hischum. 

"I don't like to suppose anything of the sort. But if they do, we'regoing down!"

"Can you get up again?"

"That remains to be seen, " was the non-committal reply. "Well, heregoes, anyhow!"

Going up into the observation tower, which was only slightly raisedabove the roof of the highest part of the tank, Tom gave the signal forthe motors to start. There was a trembling throughout the whole of thevast structure. Tom threw back a lever and Ned, peering from a sideobservation slot, beheld a strange sight. 

Like the main arm of some great steam shovel, two long, latticedgirders of steel shot out from the sides of the tank. They gave a halfturn, as they were pulled forward by the steel ropes, so that they laywith their broader surfaces uppermost. 

Straight across the stream they were pulled, their clawlike ends comingto a rest on the opposite bank. Then they were tightened into place bya backward pull on the operating cables, and Tom, with a sigh ofrelief, 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 aboutyou down there?" he called to the engine room through a telephone whichcould only be used when the machinery was not in action, there beingtoo 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 realtelling 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 propelherself over them, pick them up on the other side of Tinkle Creek, andproceed on her course. 

Tom Swift hesitated a moment, one hand on the starting lever and theother on the steering wheel. Then, with a glance at Ned, half whimsicaland half resolute, Tom started Tank A on what might prove to be herlast journey. 

Slowly the ponderous caterpillar belts moved around on the sprocketwheels. They ground with a clash of steel on the surface of thespanners. So long was the tank that the forward end, or the "nose, " washalfway across the stream before the bottom part of the endless beltsgripped the latticed bridge. 

"If we fall, we'll span the creek, not fall into it, " murmured Ned, ashe looked from the observation slot. 

"That's what I counted on, " Tom said. "We'll get out, even if we dofall. "

But Tank A was not destined to fall. In another moment her entireweight rested on the novel and transportable bridge Tom Swift hadevolved. Then, as the gripping ends of the girders sank farther intothe soil, the tank went on her way. 

Slowly, at half speed, she crawled over the steel beams, makingprogress over the creek and as safely above the water as though on aregularly constructed bridge. 

On and on she went. Now her entire weight was over the middle of thetemporary structures. If they were going to give way at all, it wouldbe at this point But they did not give. The latticed and triangularsteel, than which there is no stronger form of construction, held upthe immense weight of Tank A, and on this novel bridge she propelledherself across Tinkle Creek. 

"Well, the worst is over, " remarked Ned, as he saw the nose of the tankproject 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, dueto a jamming of one of the recovery cables, the spanners were pickedup, slid into the receiving sockets, and the great war engine was readyto proceed again. 

"Hurrah!" cried Ned. "She did it, Tom, old man!" and he clapped hischum resoundingly on the back. 

"She certainly did!" was the answer. "But you needn't knock me aparttelling me that. Go easy!"

"Bless my apple pie!" cried Mr. Damon, who was as much pleased aseither of the boys, "this is what I call great!"

"Yes, she did all that I could have hoped for, " said Tom. "Now for thenext test. "

"Bless my collar button! is there another?"

"Just down into a trench and out again. " Tom said. "This iscomparatively simple. It's only what she'll have to do every day inFlanders. "

The tank waddled on. A duck's sidewise walk is about the only kind ofmotion that can be compared to it. The going was easier now, for it wasacross a big field, and Tom told his friends that at the other end wasa deep, steep and rocky ravine in which he had decided to give the tankanother test. 

"We'll imagine that ravine is a trench, " he said, "and that we've gotto get on the other side of it. Of course, we won't be under fire, asthe tanks will be at the front, but aside from that the test will bejust 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 sideof his tank, "show them what you can do!"

"Bless my plum pudding!" cried Mr. Damon, "are you really going downthere, Tom Swift?"

"I am, " answered the young inventor. "It won't be dangerous. We'llcrawl down and crawl out. Hold fast!"

He steered the machine straight for the edge of the ravine, and as thenose slipped over and the broad steel belts bit into the earth the tanktilted downward at a sickening angle. 

She appeared to be making the descent safely, when there was a suddenchange. The earth seemed to slip out from under the broad caterpillarbelts, and then the tank moved more rapidly. 

"Tom, we're turning over!" shouted Ned. "We're capsizing!"

Chapter XIV

The Ruined Factory

Only too true were the words Ned Newton shouted to his chum. Tank A wasreally capsizing. She had advanced to the edge of the gully and starteddown it, moving slowly on the caterpillar bands of steel. Then had comea sudden lurch, caused, as they learned afterward, by the slipping offof a great quantity of shale from an underlying shelf of rock. 

This made unstable footing for the tank. One side sank lower than theother, and before Tom could neutralize this by speeding up one motorand 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 himselfthrown 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. "Itwon't hurt her. She's built for lust this sort of thing!"

And over Tank A did go. Over and over she rolled, sidewise, tumblingand sliding down the shale sides of the great gully. 

"Hold fast! Grab the rings!" cried Tom to his two companions in thetower with him. "That's what they're for!"

Ned and Mr. Damon understood. In fact, the latter had already done asTom suggested. The young inventor had read that the British tanksfrequently turned turtle, and he had this in mind when he madeprovision in his own for the safety of passengers and crew. 

As soon as he felt the tank careening, Tom had pressed the signalordering the motors stopped, and now only the force of gravity wasoperating. But that was sufficient to carry the big machine to thebottom of the gulch, whither she slid with a great cloud of sand, shaleand dust. 

"Bless my--bless my--" Mr. Damon was murmuring, but he was so floppedabout, tossed from one side to the other, and it took so much of hisattention and strength to hold on to the safety ring, that he could notproperly 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 turningimprovised somersaults, and rested in a pile of soft shale at thebottom of the gully. And the tank was resting on her back!

"We've turned turtle!" cried Ned, as he noted that he was standing onwhat, before, had been the ceiling of the observation tower. But aseverything was of steel, and as there was no movable furniture, nogreat harm was done. In fact, one could as well walk on the ceiling ofthe 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 canright her, " was the answer. 

"How?" asked Ned. 

"Well, she'll right herself if there's ground enough for the steelbelts to get a grip on. 

"But can the motors work upside down?"

"They surely can!" responded Tom. "I made 'em that way on purpose. Thegasolene feeds by air pressure, and that works standing on its head, aswell as any other way. It's going to be a bit awkward for the men tooperate the controls, but we won't be this way long. Before I start toright her, though, I want to make sure nothing is broken. "

Tom signaled to the engine room, and, as the power was off and thespeaking 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 hiredbecause he knew something about the British tanks. "'Twas a bit ofnastiness 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 mainengine room, but Tom Swift managed it. To his delight, aside from asmall break in one of the minor machines, which would not interferewith the operation or motive force of the monster war engine, everything was in good shape. There was no leak from the gasolenetanks, which was one of the contingencies Tom feared, and, as he hadsaid, the motors would work upside down as well as right side up, afact he had proved more than once in his Hawk. 

"Well, we'll make a start, " he told his chief engineer. "Stand by whenI 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 intothe observation tower. 

"Well, I'm going to run her part way up the very steepest part of theravine I can find--the side of a house would do as well if it couldstand the strain. I'm going to stand the tank right up on her nose, soto speak, and tip her over so she'll come right again. "

Slowly the tank started off, while Tom and his friends in theobservation tower anxiously awaited the result of the novel progress. Ned and Mr. Damon clung to the safety rings. Tom put his arm throughone and hung on grimly, while he used both hands on the steeringapparatus and the controls. 

Of course the trailer wheels were useless in a case of this kind, andthe 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 sensationto be moving upside down, but it did not last very long. Tom steeredthe tank straight at the opposite wail of the ravine, where it rosesteeply. One of the broad belts ran up on that side. The other wasrevolved 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 foundthemselves standing where they belonged--on the floor of theobservation tower. 

"Right side up with care!" quoted Ned, with a laugh. "Well, that wassome 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 dowhen 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 themotor room reporting that everything was all right, and that with theexception of a slight unimportant break, no damage had been done. 

Straight for the opposite steep side of the gully Tom directed hisstrange craft, and at a point where the wall of the gulch gave a goodfooting for the steel belts, Tank A pulled herself out and up to levelground. 

"Well, I'm glad that's over, " remarked Ned, with a sigh of relief, asthe tank waddled along a straight stretch. "And to think of having todo that same thing under heavy fire!"

"That's part of the game, " remarked Tom. "And don't forget that we canfire, too--or we'll be able to when I get the guns in place. They'llhelp to balance the machine better, too, and render her less likely tooverturn. "

Tom considered the test a satisfactory one and, a little later, guidedhis tank back to the shop, where men were set to work repairing thelittle damage done and making some adjustments. 

"What's next on the program?" asked Ned of his chum one day about aweek later. "Any more tests in view?"

"Yes, " answered Tom. "I've got the machine guns in place now. We aregoing to try them out and also endeavor to demolish a building and somebarbed wire. Like to come along?"

"I would!" cried Ned. 

A little later the tank was making her way over a field. Tom pointedtoward a deserted factory, which had long been partly in ruins, butsome of the walls of which still stood. 

"I'm going to bombard that, " he announced, and then try to batter itdown 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'regoing against the Germans!"

Slowly, but with resistless energy, the tank approached the ruinedfactory. 

"Are you sure there's no one in it, Tom?"

"Sure! Blaze away!"

Chapter XV

Across Country

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 weaponlike this, erected on a stationary tripod. But this was the first timeNed had attempted to fire from the tank while it was moving, and hefound it an altogether different matter. 

"Say, it sure is hard to aim where you want to!" he shouted across toTom, it being necessary, even in the conning tower, where this one gunwas 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, andbelow and to the rear of the two young men. 

"Well, that's part of the game, " Tom answered. "I'm sending her alongover as smooth ground as I can pick out, but it's rough at best. Stillthis is nothing to what you'll get in Flanders. "

"If I get there!" exclaimed Ned grimly. "Well, here goes!" and oncemore he tried to aim the machine gun at the middle of the brick wall ofthe ruined factory. 

A moment later there was a rattle and a roar as the quick-firingmechanism started, and a veritable hail of bullets swept out at themasonry. Tom and Ned could see where they struck, knocking off bits ofstone, brick and cement. 

"Sweep it, Ned! Sweep it!" cried Tom. "Imagine a crowd of Germans arecharging out at you, and sweep 'em out of the way!"

Obeying this command, the young man moved the barrel of the machine gunfrom side to side and slightly up and down. The effect was at onceapparent. The wall showed spatter-marks of the bullets over a widerarea, and had a body of Teutons been before the factory, or even insideit, many of them would have been accounted for, since there wereseveral holes in the wall through which Ned's bullets sped, carryingpotential death with them. 

"That's better!" shouted Tom. "That'll do the business! Now I'm goingto 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 takeit 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'llbutt into that wall, crush it down by force and weight, and then waddleover the ruins. Watch!"

Tom sent some signals to the motor room. At once there was noticed anincrease 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 ruinedcondition, some of the walls were still firm, and seemed to offer a bigobstacle 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 youcut loose with the machine gun again. This gun is supposed to firestraight ahead and a little to either side. There are other guns atleft and right, amidships, as I might say, and there's also one in thestern, to take care of any attack from that direction. 

"The men in charge of them will fire at the same time you do, and itwill be as near like a real attack as we can make it--with theexception of not being fired back at. And I wouldn't mind if such werethe 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 tothe deserted factory. Ned and Tom, in the conning tower, saw thelargest of the remaining walls looming before them. Straight at itrushed the ponderous machine, and the next moment there came a shockwhich almost threw Ned away from his gun and back against the steelwall 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 walland crumpled it up. 

A great hole was made in the masonry, and what was not crushed underthe caterpillar belts of the tank fell in a shower of bricks, stone andcement on top of the machine. 

Like a great hail storm the broken masonry pelted the steel sides andtop of the tank. But she felt them no more than does an alligator theattacks of a colony of ants. Right on through the dust the tankcrushed her way. Added to the noise of the falling walls was that ofthe machine guns, which were barking away like a kennel of angry houndseager to be unleashed at the quarry. 

Ned kept his gun going until the heat of it warned him to stop and letthe barrel cool, or he knew he would jam some of the mechanism. Theother guns were firing, too, and the bullets sent up little spatterpoints of dust as they hit. 

"Great jumping hoptoads!" yelled Ned above the riot of racket outsideand 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 oldfactory, permission to complete the demolition of which Tom had securedfrom the owners. Then the great machine kept right on. She fairly"walked" over the piles of masonry, dipped down into what had been abasement, now partly filled with debris, and kept on toward anotherwall. 

"I'm going through that, too!" cried Tom. 

And he did, knocking it down and sending his tank over the piled-upruins, while the machine guns barked, coughed and spluttered, as Nedand the others inside the tank held back the firing levers. 

Right through the opposite wall, as through the one she had alreadydemolished, the tank careened on her way, to emerge, rather batteredand 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 itsdemolition. 

"If there'd been a nest of Germans in there, " said Tom, as he broughtthe machine to a stop in a field beyond the factory, "they'd havegotten out in a hurry. "

"Or taken the consequences, " added Ned, as he wiped the sweat from hispowder-blackened and oil-smeared face. "I certainly kept my gun going. "

"Yes, and so did the others, " reported one of the mechanics, as heemerged from the "cubby hole, " where the great motors had now ceasedtheir hum and roar. 

"How'd she stand it?" asked Tom. 

"All right inside, " answered the man. "I was wondering how she looksfrom the outside. "

"Oh, it would take more than that to damage her, " said Tom, withpardonable pride. "That was pie for her! Solid concrete, which she mayhave to chew up on the Western front, may present another kind ofproblem, but I guess she'll be able to master that too. Well, let'shave 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 appearanceshe 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 broadback. 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 hardesttest to which she could have been submitted, but it will do to showwhat punishment she can stand. Being shot at from big guns is anothermatter. I'll have to wait until she gets to Flanders to see what effectthat will have. But I know the kind of armor skin she has, and thatdoesn't worry me. There's one thing more I want to do while I have herout now. "

"What's that?" asked Ned. 

"Take her for a long trip cross country, and then shove her throughsome extra heavy barbed wire. I'm certain she'll chew that up, but Iwant 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 aswe go along. "

The tank started off across the fields, which stretched for many mileson either side of the deserted factory, when suddenly Ned, who wasagain at his post in the observation tower, called:

"Look, Tom!"

"What at?"

"That corner of the factory which is still standing. Look at those mencoming out and running away!"

Ned pointed, and his chum, leaning over from the steering wheel andcontrols, gave a start of surprise as he saw three figures clamberingdown over the broken debris and making their way out of what had oncebeen a doorway. 

"Did they come out of the factory, Ned?"

"They surely did! And unless I miss my guess they were in it, or aroundit, when we went through like a fellow carrying the football over theline 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 westarted away. "

"This has got to be looked into!" decided Tom. "Come on, Ned! It may bemore of that spy business!"

Tom Swift stopped the tank and prepared to get out

Chapter XVI

The Old Barn

"There's no use chasing after 'em, Tom, " observed Ned, as the two chumsstood side by side outside the tank and gazed after the three menrunning off across the fields as fast as they could go. "They've gottoo much a start of us. "

"I guess you're right, Ned, " agreed Tom. "And we can't very well pursuethem in the tank. She goes a bit faster than anything of her build, buta running man is more than a match for her in a short distance. If Ihad the Hawk here, there'd be a different story to tell. "

"Well, seeing that you haven't, " replied Ned, "suppose we let themgo--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 factoryfarthest 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 buildingwhen the factory was in operation. A door, from which most of the glasshad been broken, hung on one hinge, and, pushing this open, the twochums found themselves in a room that bore evidences of having been thebookkeeper's department. There were the remains of cabinet files, and abroken 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 thecombination is broken--any one can open it, " and he demonstrated thisby swinging back one of the heavy doors. 

A quantity of papers fell out, or what had been papers, for they werenow 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. " Andhe tested them with his hand. "They wanted to destroy something, andwhen they found we were here they clapped the blazing stuff into thesafe, thinking it would burn there. 

"But the closing of the doors cut off the supply of air and the firesmouldered and went out. It burned enough so that it didn't leave usvery much in the way of evidence, though, " went on Tom ruefully, as hepoked 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 themass. "I don't believe it would be worth while to try it. Still, Ican save it. Here, I'll sweep the stuff into a box, and if we get achance we can try to patch it together, " and finding a broken box inwhat had been the factory office the young inventor managed to get intoit the charred remains of the papers. 

A further search failed to reveal anything that would be useful in theway of evidence to determine what object the three men could have hadin 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 tostart off once more for the cross-country test. 

"Well, it seems like a silly thing to say--as if I imagined my tank wasall there was in this part of the country to make trouble--but Ibelieve those men had some connection with Simpson and with that spySchwen!"

"I agree with you!" exclaimed Ned. "And I think if we could get head ortail of those burned papers we'd find that there was somecorrespondence there between the man I saw up the tree and the workmanyou had arrested. "

"Too bad we weren't a bit quicker, " commented Tom. "They must have beenin the factory when we charged it--probably came there to be inseclusion while they talked, plotted and planned. They must have beenafraid 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 runningthey had their backs toward me. Was Simpson one?"

"I can't be sure. If one was, I guess he'll think we are keeping prettyclosely after him, and he may give this part of the country a wideberth. "

"I hope he does, " returned Tom. "Do you know, Ned, I have an idea thatthese fellows--Schwen Simpson, and those back of them, includingBlakeson--are trying to get hold of the secret of my tank for theGermans. "

"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 themechanism of the tank--the way I've increased the speed and power, theuse of the spanners, and things like that--which would be useful forthe 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 intheir 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 fellowBlakeson is in the pay of the plotters, I believe. He has a big machineshop, and he might try to duplicate my tank if he knew how she was madeinside. "

"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 wastalking to the time your Hawk met with the little mishap. "

"Yes, I guess maybe he will be a bit startled, " agreed Tom. "But Ihaven'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 notat small or big ditches, flow going uphill and now down, across astretch of country thinly settled, where even fences were a rarity. When they came to wooden ones Tom had the workmen get out and take downthe bars. Of course the tank could have crushed them like toothpicks, but Tom was mindful of the rights of farmers, and a broken fence mightmean strayed cows, or the letting of cattle into a field of grain orcorn, to the damage of both cattle and fodder. 

"There's a barbed-wire fence, " observed Ned, as he pointed to one offsome 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 puttingit up again. When I make the barbed-wire test I want some set up onheavy posts, and with many strands, as it is in Flanders. Even thatwon't stop the tank, but I'm anxious to see how she breaks up the wireand supports--just what sort of a breach she makes. But I have adifferent plan in mind now. 

"I'm going to try to find a wooden building we can charge as we did themasonry factory. I want to smash up a barn, and I'll have to pick outan old one for choice, for in these war days we must conserve all wecan, 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 sameconditions she'll meet with on the Western front. We've proved that abrick 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 abarn when smashed will get tangled up in the endless steel belts, andclog them so they'll jam. That's the reason I want to try a woodenstructure next. "

"Do you know where to find one?"

"Yes; about a mile from here is one I've had my eyes on ever since Ibegan constructing the tank. I don't know who owns it, but it's such aramshackle affair that he can't object to having it knocked intokindling wood for him. If he does holler, I can pay him for the damagedone. So now for a barn, Ned, unless you're getting tired and want togo back?"

"I should say not! Speaking of barns, I'm with you till the cows comehome! Want any more machine gun work?"

"No, I guess not. This barn isn't particularly isolated, and theshooting might scare horses and cattle. We can smash things up withoutthe guns. "

The tank was going on smoothly when suddenly there was a lurch to oneside, 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 thebelts 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 hefound 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 boysdropped his monkey wrench and it smashed some spark plugs. That causeda short circuit and the left hand motor went out of business. We'llhave her fixed in a jiffy. "

Tom looked relieved, and the machinist was as good as his word. In afew minutes the tank was moving forward again. It crossed out to theroad, to the great astonishment of some farmers, and the fright oftheir 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 asbad 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 itskind, Tank A, under the guidance of Tom Swift, reeled and bumped herway over the uneven fields toward the old barn. Within the monster ofsteel and iron were raucous noises: the clang and clatter of thepowerful gasolene motors; the rattle of the wheels and gears; allmaking so much noise that, in the engine room proper, not a word couldbe heard. Every order had to be given by signs, and Tom sent hiselectric signals from the conning tower in the same way. When runningat full speed, it was almost impossible, even in the tower, which wassome distance removed from the engine room, to hear voices unless thewords were shouted. 

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

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

"So I want to come up through that gully, and go at the barn from thelong way. That will be the worst possible way I could do it, and if oldTank 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 justthen Tom signaled for more speed, and the consequent increase in therattling and banging noises made it correspondingly difficult for talkto be heard. 

The big machine now tipped into the little gully spoken of by Tom. Thismeant a dip downward, and then a climb out again and an attack on thebarn 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 hisponderous 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 ahalf-amused smile at his chum, and then threw over the guiding lever. 

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

Now the big machine reached the bottom of the gulch and started up thesides, which, though not as steep as the trench in which she hadcapsized, 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 wasat the top, and then a forward careening motion told that she hadpassed over the summit and was ready for the attack proper. 

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

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

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

"But, " shouted Ned, "don't you understand? I saw a man come out ofthere! 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 ateher way through the old barn as a rat might eat his way into a softcheese, 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 theweight of great beams on her back, caring nothing for those that got inthe way of her steel belts, heeding not the wall of wood that reareditself before her in a barrier of splinters and slivers, Tank A went onand on until finally, with another grinding crash, as she smashed herway through the farthermost wall, the great engine of war emerged onthe other side and came panting into the field, dragging with her apart of the structure clinging to her steel sides. 

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

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

"I heard you yelling something to me, but I was too anxious to go at itas 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 youtackled the barn for a knockdown, instead of a touchdown, as we mightsay, 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. "Iwish I had seen him. But, Ned, if one ran out of harm's way, any otherswho 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. "Ifanything has happened--"

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

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

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

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

"Well, if there was anybody in that barn when we chewed her up Iwouldn'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 intheir hearts. No more complete ruin could be imagined. If a cyclone hadswept 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 weightof the tank, but the boards and beams were broken into small pieces. Parts of them clung in long, grotesque splinters to the endless steelbelts. 

"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 oneis there he may have been off to one side or to one end, and beprotected 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, Ireally 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 reachedit when from around the corner swung a big automobile. In it wereseveral men, but chief, in vision at least, among them, was a burlyfarmer who had a long, old-fashioned gun in his hands. On his beardedface was a grim look as he leaped out before the machine had fairlystopped, and called:

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

Chapter XVIII

Ready for France

Such was the reaction following the crashing through of the barn, coupled with the sudden appearance of the men in the automobile and thethreat of the farmer, that, for the moment, Tom, Ned, or theircompanions from the tank could say nothing. They just stood staring atthe farmer with the gun, while he grimly regarded them. It was Tom whospoke first. 

"What's the idea?" asked the young inventor. "Why don't you want us tolook through the ruins?"

"You'll learn soon enough!" was the grim answer. 

But Tom was not to be put off with undecided talk. 

"If there's been an accident, " he said, "we're sorry for it. But delaymay be dangerous. If some one is hurt--"

"You'll be hurt, if I have my way about it!" snapped the farmer, "andhurt in a place where it always tells. I mean your pocketbook! That'sthe kind of a man I am--practical. "

"He means if we've killed or injured any one we'll have to paydamages, " whispered Ned to Tom. "But don't agree to anything until yousee your lawyer. That's a hot one, though, trying to claim damagesbefore he knows who's hurt!"

"I've got to find out more about this, " Tom answered. He started towalk on. 

"No you don't!" cried the farmer, with a snarl. "As I said, you folkshas done damage enough with your threshing machine, or whatever youcall it. Now you've got to pay!"

"We are willing to, " said Tom, as courteously as he could. "But firstwe want to know who has been hurt, or possibly killed. Don't you thinkit best to get them to a doctor, and then talk about money damageslater?"

"Doctor? Hurt?" cried the farmer, the other men in the auto sayingnothing. "Who said anything about that?"

"I thought, " began Tom, "that you--"

"I'm talkin' about damages to my barn!" cried the farmer. "You had noright to go smashing it up this way, and you've got to pay for it, ormy name ain't Amos Kanker!"

"Oh!" and there was great relief in Tom's voice. "Then we haven'tkilled any one?"

"I don't know what you've done, " answered the farmer, and his voice wasnot a pleasant one. "I'm sure I can't keep track of all your ructions. All I know is that you've ruined my barn, and you've got to pay for it, and pay good, too!"

"For that old ramshackle?" cried Ned. 

"Hush!" begged Tom, in a low voice. "I'm willing to pay, Ned, for thesake of having proved what my tank could do. I'm only too glad tolearn no one was hurt. Was there?" he asked, turning to the farmer. 

"Was there what?"

"Was there anybody in your barn?"

"Not as I knows on, " was the grouchy answer. "A man who saw yourmachine coming thought she was headed for my building, and he run andtold me. Then some friends of mine brought me here in their machine. Itell you I've got all the evidence I need ag'in you, an' I'm going tohave damages! That barn was worth three thousand dollars if it wasworth a cent, and--"

"This matter can easily be settled, " said Tom, trying to keep histemper. "My name is Swift, and--"

"Don't get swift with me, that's all I ask!" and the farmer laughedgrimly at his clumsy joke. 

"I'll do whatever is right, " Tom said, with dignity. "I live over nearShopton, and if you want to send your lawyer to see mine, why--"

"I don't believe in lawyers!" broke in the farmer. "All they think ofis to get what they can for theirselves. And I can do that myself. I'llget it out of you before you leave, or, anyhow, before you take yourcontraption away, " and he glanced at the tank. 

The same suspicion came at once to Tom and Ned, and the latter gavevoice to it when he murmured in a low voice to his chum:

"This is a frame-up--a scheme, Tom. He doesn't care a rap for thebarn. It's some of that Blakeson's doing, to make trouble for you. "

"I believe you!" agreed Tom. "Now I know what to do. "

He looked toward the collapsed barn, as if making a mental computationof its value, and then turned toward the farmer. 

"I'm very sorry, " said Tom, "if I have caused any trouble. I wanted totest my machine out on a wooden structure, and I picked your barn. Isuppose I should have come to you first, but I did not want to wastetime. I saw the barn was of practically no value. "

"No value!" broke in the farmer. "Well, I'll show you, young man, thatyou can't play fast and loose with other people's property and notsettle!"

"I'm perfectly willing to, Mr. Kanker. I could see that the barn wasalmost ready to fall, and I had already determined, before sending mytank through it, to pay the owner any reasonable sum. I am willing todo that now. "

"Well, of course if you're so ready to do that, " replied the farmer, and Ned thought he caught a glance pass between him and one of the menin the auto, "if you're ready to do that, just hand over three thousanddollars, and we'll call it a day's work. It's really worth more, butI'll say three thousand for a quick settlement. "

"Why, this barn, " cried Ned, "isn't worth half that! I know somethingabout real estate values, for our bank makes loans on farms aroundhere--"

"Your bank ain't made me no loans, young man!" snapped Mr. Kanker. "Idon't need none. My place is free and clear! And three thousand dollarsis the price of my barn you've knocked to smithereens. If you don'twant to pay, I'll find a way to make you. And I'll hold you, or yourtank, as you call it, security for my damages! You can take your choiceabout that. "

"You can't hold us!" cried Tom. "Such things aren't done here!"

"Well, then, I'll hold your tank!" cried the farmer. "I guess it'llsell for pretty nigh onto what you owe me, though what it's good for Ican't see. So you pay me three thousand dollars or leave your machinehere as security. "

"That's the game!" whispered Ned. "There's some plot here. They wantto get possession of your tank, Tom, and they've seized on this chanceto do it. "

"I believe you, " agreed the young inventor. "Well, they'll find thattwo can play at that game. Mr. Kanker, " he went on, "it is out of thequestion to claim your barn is worth three thousand dollars. "

"Oh, is it?" sneered the farmer. "Well, I didn't ask you to come hereand make kindling wood of it! That was your doings, and you've had yourfun out of it. Now you can pay the piper, and I'm here to make youpay!" And he brought the gun around in a menacing manner. 

"He's right, in a way, " said Ned to his chum. "We should have securedhis permission first. He's got us in a corner, and almost any jury offarmers around here, after they heard the story of the smashed barn, would give him heavy damages. It isn't so much that the barn is worththat as it is his property rights that we've violated. A farmer's barnis his castle, so to speak. "

"I guess you're right, " agreed Tom, with a rather rueful face. "But I'mnot going to hand him over three thousand dollars. In fact, I haven'tthat much with me. "

"Oh, well, I don't suppose he'd want it all in cash. "

But, it appeared, that was just what the farmer wanted. He went overall his arguments again, and it could not be denied that he had the lawon his side. As he rightly said, Tom could not expect to go about thecountry, "smashing up barns and such like, " without being willing topay. 

"Well, what you going to do?" asked the farmer at last. "I can't stayhere all day. I've got work to do. I can't go around smashing barns. Iwant three thousand dollars, or I'll hold your contraption forsecurity. "

This last he announced with more conviction after he had had a talkwith one of the men in the automobile. And it was this consultationthat confirmed Tom and Ned in their belief that the whole thing was aplot, growing out of Tom's rather reckless destruction of the barn; aplot on the part of Blakeson and his gang. That they had so speedilytaken advantage of this situation carelessly given them was onlyanother evidence of how closely they were on Tom's trail. 

"That man who ran out of the barn must have been the same one who wasin the factory, " whispered Ned to his chum. "He probably saw us comingthis way and ran on ahead to have the farmer all primed in readiness. Maybe he knew you had planned to ram the barn. "

"Maybe he did. I've had it in mind for some time, and spoken to some ofmy men about it. "

"More traitors in camp, then, I'm afraid, Tom. We'll have to do somemore detective work. But let's get this thing settled. He only wants tohold your tank, and that will give the man, into whose hands he'splaying, a chance to inspect her. "

"I believe you. But if I have to leave her here I'll leave some men onguard inside. It won't be any worse than being stalled in No Man'sLand. In fact, it won't be so bad. But I'll do that rather than begouged. "

"No, Tom, you won't. If you did leave some one on guard, there'd be toomuch chance of their getting the best of him. You must take your tankaway with you. "

"But how can I? I can't put up three thousand dollars in cash, and hesays he won't take a check for fear I'll stop payment. I see his game, but I don't see how to block it. "

"But I do!" cried Ned. 

"What!" exclaimed Tom. "You don't mean to say, even if you do work in abank, that you've got three thousand in cash concealed about yourperson, do you?"

"Pretty nearly, Tom, or what is just as good. I have that amount inLiberty Bonds. I was going to deliver them to a customer who hasordered them but not paid for them. They are charged up against me atthe bank, but I'm good for that, I guess. Now I'll loan you thesebonds, and you can give them to this cranky old farmer as security fordamages. Mind, don't make them as a payment. They're simplysecurity--the same as when an autoist leaves his car as bail. Only wedon't want to leave our car, we'd rather have it with us, " and helooked over at the tank, bristling with splinters from the demolishedbarn. 

"Well, I guess that's the only way out, " said Tom. "Lucky you had thosebonds with you. I'll take them, and give you a receipt for them. Infact, I'll buy them from you and let the farmer hold them as security. "

And this, eventually, was done. After much hemming and hawing andconsultation with the men in the automobile, Mr. Kanker said he wouldaccept the bonds. It was made clear that they were not in payment ofany damages, though Tom admitted he was liable for some, but that UncleSam's war securities were only a sort of bail, given to indicate that, some time later, when a jury had passed on the matter, the younginventor would pay Mr. Kanker whatever sum was agreed upon as just. 

"And now, " said Tom, as politely as he could under the circumstances, "I suppose we will be allowed to depart. "

"Yes, take your old shebang offen my property!" ordered Mr. Kanker, with no very good grace. "And if you go knocking down any more barns, I'll double the price on you!"

"I guess he's a bit roiled because he couldn't hold the tank, " observedNed to Tom, as they walked together to the big machine. "Hisfriends--our enemies--evidently hoped that was what could be done. Theywant to get at some of the secrets. "

"I suppose so, " conceded Tom. "Well, we're out of that, and I've provedall I want to. "

"But I haven't--quite, " said Ned. 

"What's missing?" asked his chum, as they got back in the tank. 

"Well, I'd like to make sure that the fellow who ran from the factorywas the same one I saw sneaking out of the barn. I believe he was, andI believe that Simpson's crowd engineered this whole thing. "

"I believe so, too, " Tom agreed. "The next thing is to prove it. Butthat will keep until later. The main thing is we've got our tank, andnow I'm going to get her ready for France. "

"Will she be in shape to ship soon?" asked Ned. 

"Yes, if nothing more happens. I've got a few little changes andadjustments to make, and then she'll be ready for the last test--one oflong distance endurance mainly. After that, apart she comes to go tothe front, and we'll begin making 'em in quantities here and on theother side. "

"Good!" cried Ned. "Down with the Huns!"

Without further incident of moment they went back to the headquartersof the tank, and soon the great machine was safe in the shop where shehad been made. 

The next two weeks were busy ones for Tom, and in them he put thefinishing touches on his machine, gave it a long test over fields andthrough woods, until finally he announced:

"She's as complete as I can make her! She's ready for France!"

Chapter XIX

Tom is Missing

With Tom Swift's announcement, that his tank was at last ready for realaction, came the end of the long nights and days given over on the partof his father, himself, and his men to the development and refinementof the machine, to getting plans and specifications ready so that thetanks could be made quickly and in large numbers in this country andabroad and to the actual building of Tank A. Now all this was done atlast, and the first completed tank was ready to be shipped. 

Meanwhile the matter of the demolished barn had been left for legalaction. Tom and Ned, it developed, had done the proper thing under thecircumstances, and they were sure they had foiled at least one plan ofthe plotters. 

"But they won't stop there, " declared Ned, who had constituted himselfa sort of detective. "They're lying back and waiting for anotherchance, Tom. "

"Well, they won't get it at my tank!" declared the young inventor, witha smile. "I've finished testing her on the road. All I need do now isto run her around this place if I have to; and there won't be much needof that before she's taken apart for shipment. Did you get any trace ofSimpson or the men who are with him--Blakeson and the others?"

"No, " Ned answered. "I've been nosing around about that farmer, Kanker, but I can't get anything out of him. For all that, I'm sure he wasegged on to his hold-up game by some of your enemies. Everything pointsthat way. "

"I think you're right, " agreed Tom. "Well, we won't bother any moreabout him. When the trial comes on, I'll pay what the jury says isright. It'll be worth it, for I proved that Tank A can eat up brick, stone or wooden buildings and not get indigestion. That's what I setout to do. So don't worry any more about it, Ned. "

"I'm not worrying, but I'd like to get the best of those fellows. Theidea of asking three thousand dollars for a shell of a barn!"

"Never mind, " replied Tom. "We'll come out all right. "

Now that the Liberty Loan drive had somewhat slackened, Ned had moreleisure time, and he spent parts of his days and not a few of hisevenings at Tom Swift's. Mr. Damon was also a frequent visitor, and henever tired of viewing the tank. Every chance he got, when they testedthe big machine in the large field, so well fenced in, the eccentricman was on hand, with his "bless my--!" whatever happened to come mostreadily to his mind. 

Tom, now that his invention was well-nigh perfected, was not so worriedabout not having the tank seen, even at close range, and the enclosurewas not so strictly guarded. 

This in a measure was disappointing to Eradicate, who liked theimportance of strutting about with a nickel shield pinned to his coat, to show that he was a member of the Swift & Company plant. As for thegiant Koku, he really cared little what he did, so long as he pleasedTom, for whom he had an affection that never changed. Koku would assoon sit under a shady tree doing nothing as watch for spies ortraitors, of whose identity he was never sure. 

So it came that there was not so strict a guard about the place, andTom and Ned had more time to themselves. Not that the young inventorwas not busy, for the details of shipping Tank A to France came to him, as did also the arrangements for making others in this country andplanning for the manufacture abroad. 

It was one evening, after a particularly hard day's work, when Tom hadbeen making a test in turning the tank in a small space in the enclosedyard, that the two young men were sitting in the machine shop, discussing various matters. 

The telephone bell rang, and Ned, being nearest, answered. 

"It's for you, Tom, " he said, and there was a smile on the face of theyoung bank clerk. 

"Um!" murmured Tom, and he smiled also. 

Ned could not repress more smiles as Tom took up the conversation overthe wire, and it did not take long for the chum of the youthfulinventor to verify his guess that Mary Nestor was at the other end ofthe instrument. 

"Yes, yes, " Tom was heard to say. "Why, of course, I'll be glad to comeover. Yes, he's here. What? Bring him along? I will if he'll come. Oh, tell him Helen is there! 'Nough said! He'll come, all right!"

And Tom, without troubling to consult his friend, hung up the receiver. 

"What's that you're committing me to?" asked Ned. 

"Oh, Mary wants us to come over and spend the evening. Helen Sever isthere, and they say we can take them downtown if we like. "

"I guess we like, " laughed Ned. "Come along! We've had enough of mustyold problems, " for he had been helping Tom in some calculationsregarding strength of materials and the weight-bearing power oftriangularly constructed girders as compared to the arched variety. 

"Yes, I guess it will do us good to get out, " and the two friends weresoon on their way. 

"What's this?" asked Mary, with a laugh, as Tom held out a package tiedwith pink string. "More dynamite?" she added, referring to an incidentwhich had once greatly perturbed the excitable Mr. Nestor. 

"If she doesn't want it, perhaps Helen will take it, " suggested Ned, with a twinkle in his eyes. "Halloran said they were just in fresh--"

"Oh, you delightful boy!" cried Helen. "I'm just dying for somechocolates! Let me open them, Mary, if you're afraid of dynamite. "

"The only powder in them, " said Tom, "is the powdered sugar. That can'tblow you up. "

And then the young people made merry, Tom, for the time being, forgetting all about his tank. 

It was rather late when the two young men strolled back toward theSwift home, Ned walking that way with his chum. Tom started out in thedirection of the building where the tank was housed. 

"Going to have a good-night look at her?" asked Ned. 

"Well, I want to make sure the watchman is on guard. We'll begin takingher apart in a few days, and I don't want anything to happen betweennow and then. "

They walked on toward the big structure, and, as they approached fromthe side, they were both startled to see a dark shadow--at least so itseemed to the youths--dart away from one of the windows. 

"Look!" gasped Ned. 

"Hello, there!" cried Tom sharply. "Who's that? Who are you?"

There was no answer, and then the fleeing shadow was merged in theother blackness of the night. 

"Maybe it was the watchman making his rounds, " suggested Ned. 

"No, " answered Tom, as he broke into a run. "If it was, he'd haveanswered. There's something wrong here!"

But he could find nothing when he reached the window from which he andNed had seen the shadow dart. An examination by means of a pocketelectric light betrayed nothing wrong with the sash, and if there werefootprints beneath the casement they indicated nothing, for that sideof the factory was one frequently used by the workmen. 

Tom went into the building, and, for a time, could not find thewatchman. When he did come upon the man, he found him rubbing his eyessleepily, and acting as though he had just awakened from a nap. 

"This isn't any way to be on duty!" said Tom sharply. "You're not paidfor sleeping!"

"I know it, Mr. Swift, " was the apologetic answer. "I don't know what'scome over me to-night. I never felt so sleepy in all my life. I had myusual sleep this afternoon, too, and I've drunk strong coffee to keepawake. "

"Are you sure you didn't drink anything else?"

"You know I'm a strict temperance man. "

"I know you are, " said Tom; "but I thought maybe you might have a cold, or something like that. "

"No, I haven't taken a thing. I did have a drink of soda water before Icame on duty, but that's all. "

"Where'd you get it?" asked Tom. 

"Well, a man treated me. "

"Who?"

"I don't know his name. He met me on the street and asked me how to getto Plowden's hardware store. I showed him--walked part of the way, infact--and when I left he said he was going to have some soda, and askedme to have some. I did, and it tasted good. "

"Well, don't go to sleep again, " suggested Tom good-naturedly. "Didyou hear anything at the side window a while ago?"

"Not a thing, Mr. Swift. I'll be all right now. I'll take a turnoutside in the air. "

"All right, " assented the young inventor. 

Then, as he turned to go into the house and was bidding Ned good-night, Tom said:

"I don't like this. "

"What?" asked his chum. 

"My sleepy watchman and the figure at the window. I more than halfsuspect that one of Blakeson's tools followed Kent for the purpose ofbuying him soda, only I think they might have put a drop or two ofchloral in it before he got it. That would make him sleep. "

"What are you going to do, Tom?"

"Put another man on guard. If they think they can get into the factoryat night, and steal my plans, or get ideas from my tank, I'll fool 'em. I'll have another man on guard. "

This Tom did, also telling Koku to sleep in the place, to be ready ifcalled. But there was no disturbance that night, and the next day thework of completing the tank went on with a rush. 

It was a day or so after this, and Tom had fixed on it as the time fortaking the big machine apart for shipment, that Ned received atelephone message at the bank from Mr. Damon. 

"Is Tom Swift over with you?" inquired the eccentric man. 

"No. Why?" Ned answered. 

"Well, I'm at his shop, and he isn't here. His father says he receiveda message from you a little while ago, saying to come over in a hurry, and he went. Says you told him to meet you out at that farmer Kanker'splace. I thought maybe--"

"At Kanker's place!" cried Ned. "Say, something's wrong, Mr. Damon!Isn't Tom there?"

"No; I'm at his home, and he's been gone for some time. His fathersupposed he was with you. I thought I would telephone to make sure. "

"Whew!" whistled Ned. "There's something doing here, all right, andsomething wrong! I'll be right over!" he added, as he hung up thereceiver. 

Chapter XX

The Search

"Haven't you seen anything of him?" asked Mr. Damon, as Ned jumped outof his small runabout at the Swift home as soon as possible afterreceiving the telephone message that seemed to presage something wrong. 

"Seen him? No, certainly not!" answered the young bank clerk. "I'm asmuch surprised as you are over it. What happened, anyhow?"

"Bless my memorandum pad, but I hardly know!" answered the eccentricman. "I arrived here a little while ago, stopping in merely to pay Toma visit, as I often do, and he wasn't here. His father was anxiouslywaiting for him, too, wishing to consult him about some shop matters. Mr. Swift said Tom had gone out with you, or over to your house--Iwasn't quite sure which at first--and was expected back any minute. 

"Then I called you up, " went on Mr. Damon, "and I was surprised tolearn you hadn't seen Tom. There must be something wrong, I think. "

"I'm sure of it!" exclaimed Ned. "Let's find Mr. Swift. And what'sthis about his going to meet me over at the place of that farmer, Mr. Kanker, where we had the trouble about the barn Tom demolished?"

"I hardly know, myself. Perhaps Mr. Swift can tell us. "

But Mr. Swift was able to throw but little light on Tom'sdisappearance--whether a natural or forced disappearance remained to beseen. 

"No matter where he is, we'll get him, " declared Ned. "He hasn't beenaway a great while, and it may turn out that his absence is perfectlynatural. "

"And if it's due to the plots of any of his rivals, " said Mr. Damon, "I'll denounce them all as traitors, bless my insurance policy, if Idon't! And that's what they are! They're playing into the hands of theenemy!"

"All right, " said Ned. "But the thing to do now is to get Tom. PerhapsMrs. Baggert can help us. "

It developed that the housekeeper was of more assistance in givinginformation than was Mr. Swift. 

"It was several hours ago, " she said, "that the telephone rang and someone asked for Tom. The operator shifted the call to the phone out inthe tank shop where he was, and Tom began to talk. The operator, as Tomhad instructed her, listened in, as Tom wants always a witness to mostmatters that go on over his wires of late. "

"What did she hear?" asked Ned eagerly. 

"She heard what she thought was your voice, I believe, " the housekeepersaid. 

"Me!" cried the young bank clerk. "I haven't talked to Tom to-day, overthe phone or any other way. But what next?"

"Well, the operator didn't listen much after that, knowing that anytalk between Tom and you was of a nature not to need a witness. Tomhung up and then he came in here, quite excited, and began to get readyto go out. "

"What was he excited about?" asked Mr. Damon. "Bless my unlucky stars, but a person ought to keep calm under such circumstances! That's theonly way to do! Keep calm! Great Scott! But if I had my way, all thoseGerman spies would be--Oh, pshaw! Nothing is too bad for them! It makesmy blood boil when I think of what they've done! Tom should have keptcool!"

"Go on. What was Tom excited about?" Ned turned to the housekeeper. 

"Well, he said you had called him to tell him to meet you over at thatfarmer's place, " went on Mrs. Baggert. "He said you had some news forhim about the men who had tried to get hold of some of his tanksecrets, and he was quite worked up over the chance of catching therascals. "

"Whew!" whistled Ned. "This is getting more complicated every minute. There's something deep here, Mr. Damon. "

"I agree with you, Ned. And the sooner we find Tom Swift the better. What next, Mrs. Baggert?"

"Well, Tom got ready and went away in his small automobile. He saidhe'd be back as soon as he could after meeting you. "

"And I never said a word to him!" cried Ned. "It's all a plot--a schemeof that Blakeson gang to get him into their power. Oh, how could Tom beso fooled? He knows my voice, over the phone as well as otherwise. Idon't see how he could be taken in. "

"Let's ask the telephone operator, " suggested Mr. Damon. "She knowsyour voice, too. Perhaps she can give us a clew. "

A talk with the young woman at the telephone switchboard in the Swiftplant brought out a new point. This was that the speaker, in responseto whose information Tom Swift had left home, had not said he was NedNewton. 

"He said, " reported Miss Blair, "that he was speaking for you, Mr. Newton, as you were busy in the bank. Whoever it was, said you wantedTom to meet you at the Kanker farm. I heard that much over the wire, and naturally supposed the message came from you. "

"Well, that puts a little different face on it, " said Mr. Damon. "Tomwasn't deceived by the voice, then, for he must have thought it wassome one speaking for you, Ned. "

"But the situation is serious, just the same, " declared Ned. "Tom hasgone to keep an appointment I never made, and the question is with whomwill he keep it?"

"That's it!" cried the eccentric man. "Probably some of thosescoundrels were waiting at the farm for him, and they've got him no oneknows where by this time!"

"Oh, hardly as bad as that, " suggested Ned. "Tom is able to look outfor himself. He'd put up a big fight before he'd permit himself to becarried off. "

"Well, what do you think did happen?" asked Mr. Damon. 

"I think they wanted to get him out to the farm to see if they couldn'tsqueeze some more money out of him, " was the answer. "Tom was prettyeasy in that barn business, and I guess Kanker was sore because hehaven't asked a larger sum. They knew Tom wouldn't come out on theirown invitation, so they forged my name, so to speak. "

"Can you get Tom back?" asked Mrs. Baggert anxiously. 

"Of course!" declared Ned, though it must be admitted he spoke withmore confidence than he really felt. "We'll begin the search rightaway. "

"And if I can get my hands on any of those villains--" spluttered Mr. Damon, dancing around, as Mrs. Baggert said, "like a hen on a hotgriddle, " which seemed to describe him very well, "if I can get hold ofany of those scoundrels, I'll--I'll--Bless my collar button, I don'tknow what I will do! Come on, Ned!"

"Yes, I guess we'd better get busy, " agreed the young bank clerk. "Tomhas gone somewhere, that's certain, and under a misapprehension. It maybe that we are needlessly alarmed, or they may mean bad business. Atany rate, it's up to us to find Tom. "

In Ned's runabout, which was a speedier car than that of the eccentricman, the two set off for Kanker's farm. On the way they stopped atvarious places in town, where Tom was in the habit of doing business, to inquire if he had been seen. 

But there was no trace of him. The next thing to do was to learn if hehad really started for the Kanker farm. 

"For if he didn't go there, " suggested Ned, "it will look funny for usto go out there making inquiries about him. And it may be that after hegot that message Tom decided not to go. "

Accordingly they made enough inquiries to establish the fact that Tomhad started for the farm of the rascally Kanker, who had been soinsistent in the matter of his almost worthless barn. 

A number of people who knew Tom well had seen him pass in the directionof Kanker's place, and some had spoken to him, for the young inventorwas well known in the vicinity of Shopton and the neighboring towns. 

"Well, out to Kanker's we'll go!" decided Ned. "And if anything hashappened to Tom there--well, we'll make whoever is responsible wish ithadn't!"

"Bless my fountain pen, but that's what we will!" chimed in Mr. Damon. 

And so the two began the search for the missing youth. 

Chapter XXI

A Prisoner

Amos Kanker came to the door of his farmhouse as Ned and Mr. Damondrove up in the runabout. There was an unpleasant grin on the not veryprepossessing face of the farmer, and what Ned thought was a cunninglook, as he slouched out and asked:

"Well, what do you want? Come to smash up any more of my barns at threethousand dollars a smash?"

"Hardly, " answered Ned shortly. "Your prices are too high for suchramshackle barns as you have. Where's Tom Swift?" he asked sharply. 

"Huh! Do you mean that young whipper-snapper with his big tractionengine?" demanded Mr. Kanker. 

"Look here!" blustered Mr. Damon, "Tom Swift is neither awhipper-snapper nor is his machine a traction engine. It's a war tank. "

"That doesn't matter much to me, " said the farmer, with a gratinglaugh. "It looks like a traction engine, though it smashes things upmore'n any one I ever saw. "

"That isn't the point, " broke in Ned. "Where is my friend, Tom Swift?That's what we want to know. "

"Huh! What makes you think I can tell you?" demanded Kanker. 

"Didn't he come out here?" asked Mr. Damon. 

"Not as I knows of, " was the surly answer. 

"Look here!" exclaimed Ned, and his tones were firm, with no blusternor bluff in them, "we came out here to find Tom Swift, and were goingto find him! We have reason to believe he's here--at least, he startedfor here, " he substituted, as he wished to make no statement he couldnot prove. "Now we don't claim we have any right to be on yourproperty, and we don't intend to stay here any longer than we can help. But we do claim the right, in common decency, to ask if you have seenanything of Tom. There may have been an accident; there may have beenfoul play; and there may be international complications in thisbusiness. If there are, those involved won't get off as easily as theythink. I'd advise you to keep a civil tongue in your head and answerour questions. If we have to get the police and detectives out here, aswell as the governmental department of justice, you may have to answertheir questions, and they won't be as decent to you as we are!"

"Hurray!" whispered Mr Damon to Ned. "That's the way to talk!"

And indeed the forceful remarks of the young bank clerk did appear tohave a salutary effect on the surly farmer. His manner changed at onceand his grin faded. 

"I don't know nothing about Tom Swift or any of your friends, " he said. "I've got my farm work to do, and I do it. It's hard enough to earn aliving these war times without taking part in plots. I haven't seen TomSwift since the trouble he made about my barn. "

"Then he hasn't been here to-day?" asked Ned. 

"No; and not for a good many days. "

Ned looked at Mr. Damon, and the two exchanged uneasy glances. Tom hadcertainly started for the Kanker farm, and indeed had come to within afew miles of it. That much was certain, as testified to by a number ofresidents along the route from Shopton, who had seen the young inventorpassing in his car. 

Now it appeared he had not arrived. The changed air of the farmerseemed to indicate that he was speaking the truth. Mr. Damon and Nedwere inclined to believe him. If they had any last, lingering doubts inthe matter, they were dispelled when Mr. Kanker said:

"You can search the place if you like. I haven't any reason to feelfriendly toward you, but I certainly don't want to get into troublewith the Government. Look around all you like. "

"No, we'll take your word for it, " said Ned, quickly concluding thatnow they had got the farmer where they wanted him, they could gain moreby an appearance of friendliness than by threats or harsh words. "Thenyou haven't seen him, either?"

"Not a sign of him. "

"One thing more, " went on Tom's chum, "and then we'll look farther. Weren't you induced by a man named Simpson, or one named Blakeson, tomake the demand of three thousand dollars' damage for your barn?"

"No, it wasn't anybody of either of those names, " admitted Mr. Kanker, evidently a bit put out by the question. 

"It was some one, though, wasn't it?" insisted Ned. 

"Waal, a man did come to me the day the barn was smashed, and justafore it happened, and said an all-fired big traction engine was headedthis way, and that a young feller who was half crazy was running it. This man--I don't know who he was, being a stranger to me--said if theengine ran into any of my property and did damages I should collect forit on the spot, or hold the machine. 

"Sure enough, that's what happened, and I did it. That man had an auto, and he brought me and some of my men out to the smashed barn. That'sall I know about it. "

"I thought some one put you up to it, " commented Ned. "This was someof the gang's work, " he went on to Mr. Damon. "They hoped to getpossession of Tom's tank long enough to find out some of the secrets. By having the Liberty Bonds, I fooled 'em. "

"That's what you did!" said Mr. Damon. "But what can we do now?"

"I don't know, " Ned was forced to admit. "But I should think we'dbetter go back to the last place where he was seen to pass in his auto, and try to get on his trail. "

Mr. Damon agreed that this was a wise plan, and, after a casual lookaround the farmhouse and other buildings on Kanker's place and findingnothing to arouse their suspicions, the two left in Ned's speedy littlemachine. 

"It is mighty queer!" remarked the young bank clerk, as they shot alongthe country road. "It isn't like Tom to get caught this way. "

"Maybe he isn't caught, " suggested the other. "Tom has been in many atight place and gotten out, as you and I well know. Maybe it will bethe same now, though it does look suspicious, that fake message comingfrom you. "

"Not coming from me, you mean, " corrected Ned. "Well, we'll do the bestwe can. "

They proceeded back to where they had last had a trace of Tom in hismachine, and there could only confirm what they had learned at first, namely, that the young inventor had departed in the direction of theKanker farm, after having filled his radiator with water, and chattingwith a farmer he knew. 

"Then this is where the trail divides, " said Ned, as they went backover the road, coming to a point where the highway branched off. "If hewent this way, he went to Kanker's place, or he would be in the way ofgoing. He isn't there, it seems, and didn't go there. "

"If he took the other road, where would he go?" asked Mr. Damon. 

"Any one of a dozen places. I guess we'll have to follow the trail andmake all the inquiries we can. "

But from the point where the two roads branched, all trace of Tom Swiftwas lost. No one had seen him in his machine, though he was known tomore than one resident along the high way. 

"Well, what are we going to do?" asked Mr. Damon, after they hadtraveled some distance and had obtained no dews. 

"Suppose we call up his home, " suggested Ned, as they came to a countrystore where there was a telephone. "It may be he has returned. In thatcase, all our worry has gone for nothing. "

"I don't believe it has, " said Mr. Damon. "But if we call up and ask ifTom is back it will show we haven't found him, and his father will bemore worried than ever. "

"We can ask the telephone girl, and tell her to keep quiet about it, "decided Ned; and this they did. 

But the answer that came back over the wire was discouraging. For Tomhad not returned, and there was no word from him. There was an urgentmessage for him, too, from government officials regarding the tank, thegirl reported. 

"Well, we've just got to find him--that's all!" declared Ned. "I guesswe'll have to make a regular search of it. I did hope we'd find him outat the Kanker farm. But since he isn't there, nor anywhere about, asfar as we can tell, we've got to try some other plan. "

"You mean notify the authorities?"--asked Mr. Damon. 

"Hardly that--yet. But I'll get some of Tom's friends who havemachines, and we'll start them out on the trail. In that way we cancover a lot of ground. "

Late that afternoon, and far into the night, a number of the friends ofTom and Ned went about the country in automobiles, seeking news of theyoung inventor. Mr. Swift became very anxious over the non-return ofhis son, and felt the authorities should be notified; but as all agreedthat the local police could not handle the matter and that it wouldhave to be put into the hands of the United States Secret Service, heconsented to wait for a while before doing this. 

All the next day the search was kept up, and Ned and Mr. Damon weregetting discouraged, not to say alarmed, when, most unexpectedly, theyreceived a clew. 

They had been traveling around the country on little-frequented roadsin the hope that perhaps Tom might have taken one and disabled hismachine so that he was unable to proceed. 

"Though in that case he could, and would, have sent word, " said Ned. 

"Unless he's hurt, " suggested Mr. Damon. 

"Well, maybe that is what's happened, " Ned was saying, when theynoticed coming toward them a very much dilapidated automobile, drivenby a farmer, and on the seat beside him was a small, barefoot boy. 

"Which is the nearest road to Shopton?" asked the man, bringing hiswheezing machine to a stop. 

"Who are you looking for in Shopton?" asked Ned, while a strangefeeling came over him that, somehow or other, Tom was concerned in thequestion. 

"I'm looking for friends of a Tom Swift, " was the answer. 

"Tom Swift? Where is he? What's happened to him?" cried Ned. 

"Bless my dyspepsia tablets!" exclaimed Mr. Damon. "Do you know wherehe is?"

"Not exactly, " answered the farmer; "but here's a note from some onethat signs himself 'Tom Swift, ' and it says he's a prisoner!"

Chapter XXII

Rescued

For a moment Ned and Mr. Damon gazed at the farmer in his rattletrap ofan auto, and then they looked at the fluttering piece of paper in hishand. Thence their gaze traveled to the ragged and barefoot lad sittingbeside the farmer. 

"I found it!" announced the boy. 

"Found what?" asked Ned. 

"That there note!"

Without asking any more questions, reserving them until they knew moreabout the matter, Mr. Damon and Ned each reached out a hand for thepaper the farmer held. The latter handed it to Ned, being nearest him, and at a sight of the handwriting the young bank clerk exclaimed:

"It's from Tom, all right!"

"What happened to him?" cried Mr. Damon. "Where is he? Is he aprisoner?"

"So it seems, " answered Ned. "Wait, I'll read It to you, " and he read:

"'Whoever picks this up please send word at once to Mr. Swift or to NedNewton in Shopton, or to Mr. Damon of Waterfield. I am a prisoner, locked in the old factory. Tom Swift'. "

"Bless my quinine pills!" cried Mr Damon. "What in the world does itmean? What factory?"

"That's just what we've got to find out, " decided Ned. "Where did youget this?" he asked the farmer's boy. 

"Way off over there, " and he pointed across miles of fields. "I waslookin' for a lost cow, and I went past an old factory. There wasn'tnobody in the place, as far as I knowed, but all at once I heard someone yell, and then I seen something white, like a bird, sail out of ahigh window. I was scared for a minute, thinkin' it might be trampsafter me. "

"And what did you do, Sonny?" asked Mr. Damon, as the boy paused. 

"Well, after a while I went to where the white thing lay, and I pickedit up. I seen it was a piece of paper, with writin' on it, and it waswrapped around part of a brick. "

"And did you go near the factory to find out who called or who threwthe paper out?" Ned queried. 

"I didn't, " the boy answered. "I was scared. I went home, and didn'teven start to find the lost cow. 

"No more he did, " chimed in the farmer. "He come runnin' in like awhitehead, and as soon as I saw the paper and heard what Bub had tosay, I thought maybe I'd better do somethin'. "

"Did you go to the factory?" asked Ned eagerly. 

"No. I thought the best thing to do would be to find this Mr. Swift, orthe other folks mentioned in this letter. I knowed, in a general way, where Shopton was, but I'd never been there, doing my tradin' in theother direction, and so I had to stop and ask the road. If you can tellme--"

"We're two of the persons spoken of in that note, " said Mr. Damon, ashe mentioned his name and introduced Ned. "We have been looking for ourfriend Tom Swift for two days now. We must find him at once, as thereis no telling what he may be suffering. "

"Where is this old factory you speak of, " continued Mr. Damon, "and howcan we get there? It's too bad one of you didn't go back, after findingthe note, to tell Tom he was soon to be rescued. "

"Waal, maybe it is, " said the farmer, a bit put out by the criticism. "But I figgered it would be better to look up this young man's friendsand let them do the rescuin', and not lose no time, 'specially as it'sabout as far from my place to the factory as it is to Shopton. "

"Well, I suppose that's so, " agreed Ned. "But what is this factory?"

"It's an old one where they started to make beet sugar, but it didn'tpan out, " the farmer said. "The place is in ruins, and I did hear, notlong ago, that somebody run a threshin' machine through it, an' bustedit up worse than before. "

"Great horned toads!" cried Ned. "That must be the very factory Tom ranhis tank through. And to think he should be a prisoner there!"

"Held by whom, do you suppose?" asked Mr. Damon. 

"By that Blakeson gang, I imagine, " Ned answered. "There's no time tolose. We must go to his rescue!"

"Of course!" agreed Mr. Damon. "We're much obliged to you for bringingthis note, " he went on to the farmer. "And here is something to repayyou for your trouble, " and he took out his wallet. 

"Shucks! I didn't do this for pay!" objected the farmer. "It's a pityI wouldn't help anybody what's in trouble! If I'd a-knowed what itmeant, me and Bub here would have gone to the factory ourselves, maybe, and done the work quicker. But I didn't know--what with war times andsuch-like--but that it would be better to deliver the note. "

"It turns out as well, perhaps, " agreed Ned. "We'll look after Tom now. "

"And I'll come along and help, " said the farmer. "If there's a gang oftramps in that factory, you may need some reinforcements. I've got acouple of new axe handles in my machine, and they'll come in mightyhandy as clubs. "

"That's so, " said Mr. Damon. "But I fancy Tom is simply locked in thedeserted factory office, with no one on guard. We can get him out oncewe get there, and we'll be glad to have you come with us. So if youwon't take any reward, maybe your boy will, as he found the note, " andMr. Damon pressed some bills into the hands of the boy, who, it isneedless to say, was glad to get them. 

It was a run of several miles hack to the deserted factory, and thoughthey passed houses on the way, it was decided that no addition to theirforce was necessary, though they did stop at a blacksmith shop, wherethey borrowed a heavy sledge to batter down a door if such actionshould be needed. 

The farmer's rattletrap of a car, in spite of its appearance, was notfar behind Ned's runabout, and in a comparatively short time all werewithin sight of the ruined place--a ruin made more complete by thepassage through it of Tom Swift's war tank. 

"And to think of his being there all this while!" exclaimed Mr. Damon, as he and Ned leaped from their machine. 

"If he only is there!" murmured the young bank clerk. 

"What do you mean? Didn't the note he threw out say he was there?"

"Yes, but something may have happened in the meanwhile. Thoseplotters, if they'd do a thing like this, are capable of anything. Theymay have kidnapped Tom again. "

"Anyway, we'll soon find out, " murmured Ned, as they advanced towardthe ruin, Mr. Damon and the farmer each armed with an axe helve, whileNed carried the blacksmith's sledge. 

They went into the end of the factory that was less ruined than thecentral part, where the tank had crashed through, and made their wayinto what had been the office--the place where they had found theburned scraps of paper. 

"Hark!" exclaimed Ned, as they climbed up the broken steps. "I heard anoise. "

"It's him yellin'--like he did afore he threw out the note, " said theboy. Then, as they listened, they heard a distant voice calling:

"Hello! Hello, there! If that is any friend of mine, let me out, orsend word to Mr. Damon or Ned Newton! Hello!"

"Hello yourself, Tom Swift!" yelled Ned, too delighted to wait for anyother confirmation that it was his friend who was shouting. "We've cometo rescue you, Tom!"

There was a moment of silence, and then a voice asked:

"Who is there?"

"Ned Newton, Mr. Damon, and some other friends of yours!" answered theyoung bank clerk, for surely the farmer and his son could be calledTom's friends. 

An indistinguishable answer came back, and then Ned cried:

"Where are you, Tom? Tell us, so we can get you out!"

They all listened, and faintly heard:

"I'm in some sort of an old vault, partly underground. It's below whatused to be the office. There's a flight of steps, but be careful, asthey're rotten. "

Eagerly they looked around Mr. Damon saw a door in one corner of theoffice, and tried to open it. It was locked, but a few blows from thesledge smashed it, and then some steps were revealed. 

Down these, using due caution, went Ned and the others, and at thebottom they came upon another door. This was of sheet iron and wasfastened on the outside by a big padlock. 

"Stand back!" cried Ned, as he swung the sledge, and with a few blowsbroke the lock to pieces. 

Then they pulled open the door, and into the light staggered Tom Swift, a most woe-begone figure, and showing the effects of his imprisonment. But he was safe and unharmed, though much disheveled from his attemptsto escape. 

"Thank Heaven, you've come!" he murmured, as he clasped Ned's hand. "Isthe tank all right?"

"All right!" cried Ned. "And now tell us about yourself. How in theworld did you get here?"

"It's quite a yarn, " answered Tom. "I've got to pull myself togetherbefore I answer, " and he sank wearily down on a step, looking veryhaggard and worn. 

Chapter XXIII

Gone

"Here, eat some of this, " and Ned held something out to his chum. "It'll bring you up quicker than anything else, except a cup of hottea, and we'll get that as soon as you can get away from here, " went onthe young bank clerk. 

"What is it?" Tom asked, and his voice was very weary. 

"It's a mixture of chocolate and nuts, " replied Ned. "It's a new formof emergency ration issued to soldiers before they go over the top. OurY. M. C. A. Is sending a lot to the boys from around here who are inFrance. I was helping pack the boxes ready for shipment, and I kept outsome to show you. Lucky I had it with me. Eat it, and you'll feel a lotbetter in a few minutes. You haven't had much to eat, have you?"

"Very little, " answered Tom, as he nibbled half-heartedly at theconfection Ned gave him, while Mr. Damon went out to the automobile andcame back with a thermos bottle filled with cool water. He alwaysprovided himself with this on taking an automobile trip. 

Tom managed to eat some of the chocolate, and then took a drink of thecool water. In a little while he declared that he felt better. 

"Then come out of here!" exclaimed Ned. "You can tell tis how it allhappened and what they did to you. But I can see that last--theytreated you like a dog, didn't they?"

"Pretty nearly, " answered Tom; "but they didn't have things all theirown way. I think I made one or two of them remember me, " and he glancedat his swollen and bruised hands. Indeed, he bore the marks of havingbeen in a fierce fight. 

"Are you sure the tank's all right?" he asked Ned again. "That hasbeen worrying me more than my own condition. I could think of only onereason why they got me here and held me prisoner, and that was to getme out of the way while they captured my tank. Then they haven't gother?" he asked eagerly. 

"Not a look at her, " Ned answered. "She was safe in the shop when weset out this morning. "

"And now it's late afternoon, " murmured Tom. "Well, I hope nothing hashappened since, " and there was vague alarm in his voice, an alarm atwhich Ned and Mr. Damon wondered. 

"Couldn't you stop at some farmhouse and get fixed up a little?" askedMr. Kimball, the farmer who had brought the note to Ned and Mr. Damon. 

"I need to get fixed up somewhere, " replied Tom, with a rueful look athimself--his hands, his torn clothes, and his general dilapidatedappearance. "But I don't want to lose any time. I'm afraid somethinghas happened at home, Ned. "

"Nonsense! How could there, with Koka on guard, to say nothing ofEradicate!"

"Well, maybe you're right, " agreed Tom; "but I'll feel better when Isee my tank in her shed. Let's have some more of that concentratedporterhouse steak of yours, Ned. It is good, and it fills out mystomach, which was getting more intimate with my backbone than I likedto feel. "

More of the really good confection and another drink of refreshingwater made Tom feel better, and he was soon able to walk along withoutstaggering from weakness. 

"And now let's get out of here, " advised Ned, "unless you've leftsomething back in that vault you want, Tom, " and he motioned to hischum's late prison. 

"Nothing there but bad memories, " was the reply, with a rueful smile. "I'm as ready to go as you are, Ned. It was good of you and Mr. Damonto come for me, and you"--and he looked questioningly at Mr. Kimball. 

"If it hadn't been for Mr. Kimball and his boy, we wouldn't have foundyou--at least so soon, " said Ned, and he told of the finding of thenote and what had followed. 

"That's the only way I could think of for getting help, " said Tom. "They took every scrap of paper from me, but I found some in the liningof my hat--some I'd stuffed in after I had a hair cut and my hat wastoo large. For a pencil I used burnt matches. Oh, but I'm glad to beout!" and he breathed deep of the fresh air. 

"How did you get in there?" asked Ned wonderingly. 

"Those fellows--of course. The German plotters, I'm going to call them, for I believe that Blakeson and his gang--though I didn't see him--arereally working in the interests of Germany to get the secret of mytank. "

"Well, they haven't got her yet, " said Ned, "and they're not likely tonow. Go on, Tom, if you feel able tell us in a few words what happened. We've been trying to think, but can't. "

"Well, it all happened because I didn't think enough, " said Tom, whowas rapidly recovering his strength and nerve. "When I got thatmessage that seemed to come from you, Ned, I should have known betterthan to take a chance. But it seemed genuine, and as I had no reason tosuspect a trap, I started off at once. I thought maybe Kanker hadrepented and was going to make amends for all the trouble he caused. 

"Anyhow, I started off in my machine, and I hadn't got more than to thecrossroads when I saw a fellow out tinkering with his auto. Of course Istopped to ask if I could help, for I can't bear to see any machineryout of order, and as I was stooping over the engine to see what waswrong I was pounced on from behind, bound and tied, and before I coulddo a thing I was bundled into the car--a big limousine, and taken away. 

"The crossroads was as far as we could trace you, " remarked Ned. 

"Well, it wasn't as far as they took me, by any means, " Tom said. "Theybrought me here, took me out of the machine--and I noticed that they'dbrought mine along--and then they carted me into the vault. 

"But they didn't have it all their own way, " said Tom grimly. "Imanaged to get the ropes loose, and I had a regular knock down and dragout with them for a while. But they were too many for me, and locked meup in that place after taking away everything I had in my pockets. "

"Were they highwaymen?" asked Mr. Kimtall. 

"No, for they tossed back my money, watch and some trifles like that, "Tom answered. "I didn't recognize any of the men, though one of themmust have known me, for when they had me tied I heard one of them askif I was the right party, and another said I was. I know they mustbelong to the same gang that Simpson, Blakeson, and Schwen are membersof--the German spies. "

"But what was their object?" asked Ned. "Did they try to force you totell them the secrets of the tank?"

"No; and that's the funny part which makes me so suspicious, " Tomanswered. "If they'd tried to force something out of me, I wouldunderstand it better. But they just kept me a prisoner after takingaway what papers I had. "

"Were they of any value?" asked Mr. Damon. 

"Not as regards the tank. That is, there was nothing of my plans ofconstruction, control or anything like that, though there was someforeign correspondence that I am sorry fell into their hands. However, that can't be helped. "

"And did they just keep you locked up?" asked Ned. 

"That's about all they did. After the fight--and it was some fight!"declared Tom, as he recalled it with a shake of his head--"they left mehere with the door shut. There must have been some one on guard, for Icould faintly hear somebody moving about. 

"I tried to get out, of course, but I couldn't. That vault must havebeen made to hold something very valuable, for it was almost as strongand solid as one in your bank, Ned. The only window was placed so highthat I couldn't reach it, and it was barred at that. 

"They opened the door a little, several times, to toss in once some oldbags that I made into a bed, and next they gave me a little water andsome sandwiches--German bologna sausage sandwiches, Ned! What do youthink of that--adding insult to injury?"

"That was tough!" Ned admitted. 

"Well, I had to put up with it, for I was half starved, and as sore asa boil from the fight. I didn't know what to do. I knew that you'd missme sooner or later, and set out to find me, but I hardly thought you'dthink of this place. They couldn't have picked out a much betterprison to hold me, for, naturally, you wouldn't suppose enough of itwas left standing, after my tank had walked through it, to make ahiding place. 

"However, there was, and here I've been kept. At last I thought of theplan of sending out a message on the scrap of paper I could tear out ofmy hat. So I wrote it, and after several trials I managed to toss itout of the window. Then I just had to wait, and that was the hardest ofall. The last twelve hours I've been without food, and I haven't heardany one around, so I guess they've skipped out and don't intend to comeback. "

"We didn't see any one, " Ned reported. "Maybe they became frightened, Tom. "

"I wish I could think that, " was the answer. "What is more likely to bethe case is that they're up to some new tricks. I must get back homequickly. "

And after a stop had been made at a farmhouse belonging to a businessacquaintance of Ned's, where Tom was able to wash and get a cup of hottea, which added to his recuperative powers, the young inventor, withNed and Mr. Damon, set out for Shopton. 

Before Mr. Kimball started for his home, renewed thanks had been madeto the farmer and his son for the part they had played in the rescue, and the young inventor, learning that the boy had a liking for thingsmechanical, promised to aid him in his intention to become a machinist. 

"But first get a good education, " Tom advised. "Keep on with yourschool work, and when the time comes I'll take you into my shop. "

"And maybe he'll make a tank that will rival yours, Tom, " said Ned. 

"Maybe he will! I hope he does. If he comes along fast enough, he canhelp with something else I'm going to start soon. "

"Whats that?" asked Mr. Damon. 

"Oh, it's something on the same order, designed to help batter down theGerman lines, " Tom answered. "I haven't quite made up my mind what tocall it yet. But let's get home. I want to see that my tank is safe. The absence of the plotters from the factory makes me suspicious. "

On the way back Tom told more of the details of the attack. 

"But we'll forget about it all, now you're out, " remarked Ned. 

"And the sooner we get home, the better, " added Tom. "Can't you get alittle more speed out of this machine?" he asked. 

"Well, it isn't the Hawk, " replied Ned, "but we'll see what we can do, "and he made the runabout fairly fly. 

Mrs. Baggert was the first to greet Tom as they arrived at his home. She did not seem as surprised as either Tom, Ned or Mr. Damon expectedher to be. 

"Well, I'm glad you're all right, " she said. "And it's a good thing yousent that note, for your father was so excited and worried I wasgetting apprehensive about him. "

"What note?" asked Tom, while a queer look came into his face. 

"Why, the one you sent saying you were detained on business and wouldprobably not be home for a week, and to have Koku and the men bring thetank to you. "

"Bring the tank! A note from me!" exclaimed Tom. "The plotters again!And they've got the tank!"

He ran to the big shop followed by the others. Throwing open the doors, they went inside. A glance sufficed to disclose the worst. 

The place where the great tank had stood was empty. 

"Gone!" gasped Tom. 

Chapter XXIV

Camouflaged

Two utterances Tom Swift made when the fact of the disappearance of thetank became known to him were characteristic of the young inventor. Thefirst was:

"How did they get it away?"

And the second was:

"Come on, let's get after 'em!"

Then, for a few moments, no one said anything. Tom, Ned, and Mr. Damon, with Mrs. Baggert in the background, stood looking at the great emptymachine shop. 

"Well, they got her, " went on Tom, with a sigh. "I was afraid of thisas soon as they left me alone at the factory. "

"Is anything wrong?" faltered the housekeeper. "Didn't you send for thetank, Tom?"

"No, Mrs. Baggert, I didn't, " Tom answered. 

"But I don't understand, " the housekeeper said. "A man came with a notefrom you, Tom, and in it you said to have him take the tank, with Kokuand the men who know how to run it. We were so glad to hear from you, and know that you were all right, that we didn't think of anythingelse, your father and I. So he went out and saw that the tank got offall right. Koku was glad, for it's the first chance he'd had to ride init. "

"Who was the man who brought the note?" asked Tom, and he was strivingto be calm. "To think of poor old dad playing right into the hands ofthe plotters!" he added, in an aside to Ned. 

"Well, I don't know who the man was, " said Mrs. Baggert. "He seemedall right, and of course having a note from you--"

"Who has that note now?" asked Tom quickly. 

"Your father. "

"Come on, " and Tom led the way back to the house. "I'll have a look atthat document, which of course I never wrote, and then we'll get afterthe plotters and the tank. "

"She ought to be easy to trace, " observed Mr. Damon. "Bless myfountain pen, but she ought to be easy to trace! She will leave atrack like a giant boa constrictor crawling along. "

"Yes, I guess we can trace her, all right, " assented Tom Swift; "butthe point is, will there be anything left of her? What's what I'mafraid of now. "

Mr. Swift was still excited, but his worry had subsided as soon as heknew Tom was safe. 

"The whole thing is a forgery, but fairly well done, " Tom said, as helooked at the paper his father gave him--a brief note stating that Tomwas well, but detained on business, and that the tank was to be broughtto him, just where the bearer of the note would indicate. Koku, thegiant, and several of the machinists, who knew how to operate the bigmachine, were to go with it, the note said. 

"That made me sure everything was all right, " said Mr. Swift. "I knew, of course, Tom, that plotters might try to get hold of your war secret, but I didn't see how they could if Koku and some of your own men werein possession. "

"They couldn't--as long as they remained in possession, " Tom said. "Butthat's the trouble. I'm afraid they haven't. What has probablyhappened is that under the direction of this man, who brought theforged note from me, Koku and the others took the tank where hedirected them, thinking to meet me. Then, reaching the place where therest of the plotters were concealed, they overpowered Koku and theothers and took possession of the machine. "

"They'd have trouble with Koku, " suggested Ned. 

"Yes, but even a giant can't fight too big a crowd, especially if he istaken by surprise, and that's probably what happened, " remarked Tom. "Now the question is where is the tank, and how can we get her back?Every minute counts. If those German spies and their helpers remain inpossession long, they'll find out enough of my secrets to enable themto duplicate the machine, and especially some of the most exclusivefeatures. We've got to get after 'em!"

"They imitated your writing pretty well, Tom, " Observed Ned, as helooked at the forged note. 

"Yes; that's why they took all my papers away from me--to get specimensof my handwriting. I half suspected that, but I didn't quite figure outwhat their game was. Well, we know the worst now, and that's betterthan working in the dark. Now I'm going to have a bath and get intosome decent clothes, and we'll see what we can do. "

"Count on me, Tom!" exclaimed Ned. "I'll go the limit with you!"

"I knew you would, old man!"

"And me, too!" cried Mr. Damon. "Bless my open fireplace, but I'll sendword to my wife that I'm not coming home to-night, and we can start thefirst thing in the morning, Tom. "

"Yes; there isn't much use in going now, as it will soon be dark. "

"How are you going to trace the tank, Tom?" asked Ned, when his chumhad bathed and gotten into fresh clothes. 

"I'm going to tour the country around here in an auto. The tank canmake ten miles an hour, but that's nothing to what an auto can do. Andwe oughtn't to have much trouble in tracing her. No one whose house shepassed would forget her in a hurry. "

"That's so, " agreed Ned. "But if they took her across country--"

"A different story, " agreed Tom. "Come to think of it, maybe we'dbetter start to-night, Ned. We can make inquiries after dark as well asby daylight and get ready for an early morning hunt. "

"Let's do it, then!" suggested his chum. "I'm ready. I'll send wordthat I'll not be home to-night. "

"Good!" cried the young inventor. "We'll have an old-fashioned huntafter our enemies, Ned!"

"And don't leave me out!" begged Mr. Damon. Hurried preparations weremade for the night trip. Tom ordered out one of his speediest, thoughnot largest, automobiles, and told his helper to get the Hawk ready, tohave her so she could start at a moment's notice if needed. 

"You're not going in her, are you, Tom?" asked Ned. 

"I may need her to-morrow for daylight hunting. If the tank's hiddensomewhere, I can spot her from above more easily than from the ground. So if we get any trace of my machine, I can phone in and have theaeroplane brought to me. "

"That's a good idea!"

Inquiry at the shop where the tank had been built and kept disclosedthe fact that, in addition to Koku, three of Tom's men had gone in herto help manage the machine under the direction of the man who bore theforged note. That he was one of the plotters not hitherto observed byeither Ned or Tom seemed certain. 

"And they took Koku and some of the men merely to make it look naturaland as if it were all right, " Tom said. "Naturally that deceived myfather, who thought, of course, that I was waiting for the machine. Well, it was a slick trick, Ned, but we may fool them yet. "

"I hope so, Tom. "

Night had fully fallen when Tom, Ned, and Mr. Damon started away in thetouring car. 

Out onto the road rolled the automobile. During the little daylightthat had remained after his arrival at home and following the discoveryof the loss of the tank Tom and Ned had traced it, by the marks of thebig steel caterpillar belts, to the main road. It had gone along thatsome distance, just how far could not be said. 

"But by using the searchlight of the auto we can trace her as long asthey keep her on the road, " said Tom. "After that we'll have to trustto luck, and to what inquiries we can make. "

The touring car carried a powerful lamp, and by its gleams it was easyto trace for a time the progress of the ponderous tank. There was noneed to make inquiries of persons living along the way, though once ortwice Tom did get out to ask, confirming the fact that the big machinehad rumbled past in a direction away from the Swift home. 

"I had an idea they might have doubled on their tracks for a time, andbacked her up just to fool us, " Tom said. "They might do that, keepingher in the same tracks. "

But this, evidently, had not been done, and the tank was making goodspeed away from the Swift Louse. They kept up the search until aboutmidnight, and then a heavy rain began just before they reached a pointwhere several roads branched. 

"Luck's with them!" exclaimed Tom. "This will wash away the marks, andwe'll have to go it blind. Might as well put up here for the night, " headded, as they came to a village hotel. 

It was evident that little more could be done in the rain and darkness, and there was danger of over-running the trail of the tank if they kepton. So they turned in at the hotel and got what little rest they couldin their anxious state of minds. 

Tom tried to be cheerful and to look for the best, but it was hardwork. The tank was his pet invention, and, moreover, that her secretsshould fall into the hands of the enemy and be used for Germany andagainst the United States eventually, made the young inventor feel thateverything was going wrong. 

The rain kept up all night, and this would make it correspondingly hardfor them to pick up the trail in the morning. 

"The only thing we can do is to make inquiries, " decided Tom. "Fortunately, the tank can't easily be hidden. "

They started off after an early breakfast. The roads were so muddy andwet that traveling was difficult and dangerous for the automobile, andthey were disappointed in finding no one who had seen or heard the tankpass up to a point not far from the hotel where they had stayedovernight. From then on the big machine seemed to have disappeared. 

"I know what they've done, " Tom said, when noon came and they had foundno trace of the ponderous war machine. "They've left the road andtaken her cross country, and we can't find the spot where they did thisbecause the rain has washed out the marks. Well, there's only one thingleft to do. "

"What's that?" asked Ned. 

"Get the Hawk! In that we can look down and over a big extent ofcountry. That's what I'll do--I'll phone for the airship. The rain isstopping, I think. "

The rain did cease by the time one of Tom's men brought the speedyaircraft to the place named by the young inventor in his telephonemessage. There were still several hours of daylight left, and Tomcounted on them to allow him to rise in the air and look down on thetanks possible hiding place. 

"One thing's sure, " he told Ned: "I know the limit of her speed, andshe can't be farther off than at some place within a circle of aboutone hundred and twenty-five miles from my house. And it's in thedirection we're in. So if I circle around up above, I may spot her. "

"I hope so, " murmured Ned. 

It was arranged that Mr. Damon should take the automobile back, withTom's mechanician in it, and Tom and Ned would scout around in theaircraft, which carried only two. 

"You ought to have a machine gun with you, Tom, if you plan to attackthose fellows to get back the tank, " Ned said. 

"Oh, I don't imagine I'll need it, " he said. "Anyhow, a machine gunwouldn't be of much effect against the tank. And they can't fire on us, for there wasn't any ammunition for the guns in Tank A, unless they gotsome of their own, and I hardly believe they'd do that. I'll take achance, anyhow. "

And so the search from the air began. It was disappointing at first. Around and around circled Tom and Ned, their eyes peering eagerly downfrom the heights for a sight of the tank, possibly hidden in somelittle-known ravine or gully. 

Back and forth, like a speck in the sky, Tom guided the Hawk, while Nedtook observation after observation with the binoculars. 

At last, when the low-sinking sun gave warning that night would soon beupon them, Ned's glasses picked up something on the ground far belowthat made him sit suddenly straighter in his seat. 

"What is it?" asked Tom through the speaking apparatus, feeling themovement on the part of his chum. 

"I see something down there, Tom, " was the answer. "It doesn't looklike the tank, and yet it doesn't look as a clump of trees and bushesought to look. Have a peep yourself. It's just beyond that river, against the side of the hill--a lonesome place, too. "

Tom took the glasses while Ned assumed control of the Hawk, there beinga dual system for operating and steering her. 

No sooner had the young inventor got the focus on what Ned hadindicated than he gave a cry. 

"What is it?" asked the young bank clerk. 

"Camouflaged!" cried Tom, and without stopping to explain what hemeant, he handed the binoculars back to Ned and began to guide the Hawkdown toward the earth at high speed. 

Chapter XXV

Foiled

"Is it really Tank A, Tom?" cried Ned, through the tube, as soon as hebecame aware of his companion's intention. "Are you sure?"

"That's the girl, and just where you spotted her with the glasses--inthat clump of bushes. But they've daubed her with green and brownpaint--camouflaged her, so to speak--until she looks like part of thelandscape. What made you suspicious of that particular place?"

"The green was such a bright one in contrast to the rest of the foliagearound it. ', "That's what struck me, " Tom answered, as he continued to drive theHawk earthward. "They thought they were doing a smart trick--imitatingthe tactics of the Allies with their tanks--but they must be colorblind. "

Ned took another observation through the glasses. He could see the tankmore easily now. There she was, fairly well hidden in a clump of bushesand small trees on the banks of a river, about a hundred miles awayfrom Shopton. It was in a wild and desolate country, and only with theairship could the trail have thus been followed. 

Ned saw that the tank had been daubed with green, yellow, and brownpaint, in fantastic blotches, to make the big machine blend with thefoliage; and, to a certain extent, this had been accomplished. 

But, as Ned had remarked, the green used was of too vivid a hue. Nonatural tree put forth leaves like that, and the glass had furtherrevealed the error. 

"Look, Tom!" suddenly cried Ned. "She's moving!"

"You're right!" answered the young inventor. "They've seen us and aretrying to get away. "

"But they can't beat your airship, Tom. "

"I know that. But their game--Oh, Ned, they're going to wreck her!"cried Tom, and there was anguish in his voice. 

As the two looked down from their seats In the Hawk they saw the tank, in its fantastic dress of splotchy paint, leave her lair amid thebushes and trees, and head toward the river. Like some ponderousprehistoric monster about to take a drink, she careened her way towardthe stream, which, at this point, ran between high banks. 

"What's the game?" cried Ned. 

"They're going to send her to smash!" cried Tom. "She's pretty tough, Tom, but she'll never stand a tumble down into the river withoutbreaking a lot of machinery inside her. "

"But if they demolish the tank they'll kill themselves, won't they?And Koku and your men, too, who must be prisoners in her!"

"They won't risk their own worthless hides, you may be sure of that!"exclaimed Tom. 

"There they go, but they must have left Koku and the others to theirfate!"

"Oh, if they could only get loose and take control now, Tom, they'dsave your tank for you!" shouted Ned. 

"Yes; but they can't, I'm afraid. They may be killed, or so securelybound that they can't get loose!"

"Can't you get the Hawk there in time to stop her?"

"I'm afraid not. By that time she'll have attained top speed and itwould be taking our lives in our bands to try to make a flying jump, get inside, and shut off the motors. "

"Then the tank's got to smash!" said Ned gloomily. 

Tom did not answer for a moment. He and his chum watched the fleeingfigures running away from the war engine. What the plotters had done, as soon as they saw the aircraft and realized that Tom had discoveredthem, was to start the motors and leap from the tank, closing the doorsafter them. Whether or not they had left Koku and the others prisonersinside remained to be seen. 

But the tank was plunging her way toward the steep bank of the river, doomed, it seemed, to great damage, if not to destruction. 

"Oh, if we could only halt her!" murmured Ned. 

Tom Swift was busy with some apparatus on the Hawk. Ned heard the humof an electric motor which was connected with the engine, and theresoon sounded the crackle of the wireless. 

"What are you doing? Signaling for help from those inside the tank?"asked Ned, for the big machine was fitted to receive and send messagesof this sort. 

"I'm trying something more desperate than that, " Tom answered. 

Again the wireless crackled, Tom working it with one hand while, withthe other, he guided the aircraft. Ned looked downward with wonderingeyes. 

The tank was still plunging her way toward the steep bank of the river. If she tumbled down this, there would be little left of the expensiveand complicated machinery inside. 

"The rascals did their work well, " mused Ned. "They've probably gottenall the secrets they want and now they're going to spoil all Tom's hardwork. It's a shame! If only--"

Ned ceased his musing. Something was taking place down below that hecould not explain. The tank seemed to be slackening her progress. Moreand more slowly she approached the edge of the cliff. 

"Tom! Tom!" yelled Ned. "You must have waked some of them up inside andthey've thrown the motors out of gear! Hurrah! She's stopping!"

"I believe she is!" yelled Tom. "Oh, if it only works!"

The tank was still moving, though more slowly. Still the crackle of thewireless was heard. 

And then, just as Tom shut off his own motor and let the Hawk glide onher downward way in a volplane to earth, the great, ponderous tank cameto a stop, on the very edge of the precipice at the foot of whichrolled the river. 

"Whew!" whistled Ned, as the aircraft rolled along the ground near thewar machine. "That was touch and go, Tom! They stopped her just intime. "

"You mean the wireless stopped her, " said Tom quietly. "I'm very muchafraid that if Koku and the others are alive they're still prisoners inthe craft. "

"The wireless!" gasped Ned, as he and his chum got out of the Hawk. "Doyou mean that you stopped her by wireless, Tom?"

"That's what I did. It was a desperate chance, but I took it. I hadjust installed in the tank a system of wireless control, so she couldbe guided as some torpedos and submarines are, by wireless impulsesfrom the shore. 

"Only I'd never given the tank system a tryout. It was all installed, and had worked perfectly on the small model I constructed. And when Isaw her running away, out of control as she was, I realized thewireless was the only thing that would stop her, if that would. Itmight operate just opposite to what I wanted, though, and increase herspeed. "

"But I took the chance. I set the airship wireless current to working, and tuned it in to coincide with the control of the tank. Then, bymeans of the wireless impulse I shut off the motors, which can bestopped or started by hand or by electricity. I shut 'em off. "

"And only just in time!" cried Ned. "Whew, Tom Swift, but that was aclose call!"

"I realize that myself!" said the young inventor. "This is a new ideaand has to be worked out further for our newer tanks. "

"Gee!" ejaculated Ned. "Out of date before got into use! Now let's seeabout our friends!"

It was the work of but a moment to enter the tank, and, after makingsure that the machinery was all right, Tom and Ned made their way tothe interior. In one of the smallest rooms they found Koku and theothers bound with ropes, and in a bad way. Koku was so tied with cordsand hemp as to resemble a bale of Manilla cable. 

"Cut 'em loose, Ned!" cried Tom, and the bonds were soon severed. Thencame explanations. 

As has been told, one of the plotters, whose identity was not learneduntil later, came with the forged note. The giant and Tom's men set outin the tank, and the machine was stopped at a certain place where theplotter, who gave the name of Crossleigh, told them Tom was to meet hismen. 

Out of ambush leaped Simpson and others, who overpowered the mechanics, even subduing Koku after a fierce fight, and then they took possessionof the tank, making the others prisoners. 

What happened after that could only be conjectured by Tom's men, forthey were shut up in an inner room. It seemed certain, though, that thetank was taken to some secret place and there painted to resemble theverdure. Then she went on again, coming to rest where Tom and Ned sawher. 

Meanwhile the plotters were gradually getting at the secrets ofconstruction, and they were in the midst of this work when one of themsaw the aeroplane. Rightly guessing what it portended, they lefthurriedly, still leaving the hapless men bound, and started the tank onwhat they thought would be her last trip. 

"But you saved her, Tom!" cried Ned. "You saved her with the wireless. "

And word was sent back to Shopton by the same means to tell Mr. Swift, Mr. Damon, and the others that Tom and his tank were safe. And then, alittle later, when the bound men had recovered the use of their crampedlimbs, the tank was backed away from the ledge and started on herhomeward way, Tom and Ned preceding her in the Hawk. 

Without further incident, save a slight break which was soon repaired, Tank A soon reached her harbor again, and a double guard was postedabout the shop. 

"And they won't get much more chance to steal her secrets, " said Tomthat night, when the stories had been told. 

"Why?" asked Ned. 

"We start to dismantle her at once, " Tom answered, "and she goes toEngland to be reproduced for France. "

"If only those plotters haven't stolen the secrets, " mused Ned. 

But if they had they got little good of them. For shortly afterwardgovernment secret service agents rounded up the chief members of thegang, including Simpson and Blakeson. They, with Schwen, were sent toan internment camp for the period of the war, and enough informationwas obtained from them to disclose all the workings of the plot. 

"It was just like lots of other stunts the German spies tried to putover on the good old U. S. A. , " said Tom to Ned, the day after thedismantled tank was shipped to Great Britain. "In some way the spiesfound out what I was making, and then they got hold of Blakeson andGrinder. Those fellows, who so nearly queered me in the big tunnel gamepromised to make a tank that would beat those the British at first putout, and they took some German money in advance for doing it. 

"When they found they couldn't make good, the German spies agreed tohelp them get possession of my secrets. They worked hard enough at it, too, but, thanks to you, Ned, and to Eradicate, who gave us the tip onSchwen, we beat 'em out. "

"And so it's all over, Tom?"

"Yes, practically all over. I've given all my interests in the tank toUncle Sam. It was the only way I could do my bit, at this time. ButI've something else up my sleeve. "

And those of you who care to learn what the young inventor next did maydo so by reading the next volume of this series. 

It was about a week after Tank A, as she was still officially called, had been shipped in sections that Ned Newton called at Tom's home. Hefound his chum, with a flower in his buttonhole, about to leave in hissmall runabout. 

"Oh, excuse me!" exclaimed Ned. "This is Wednesday night. I might haveknown. Give Mary my regards. "

"I will, " promised Tom, with a smile.