“what’s the idea, tom?” asked ned when his chum had returned to the middle of the big, barnlike room where he stood in front of the air monarch, contemplating the powerful machine. “what’s the game?”

“a dirty game!” snapped out tom swift. “this red arrow gang has been trying to sneak around and discover some of my secrets for a long time. this is another attempt. hussy has been here before. but i don’t think he’ll come again,” added the young inventor grimly.

“are they trying to do you out of this new contrivance?” asked ned.

“i don’t know that they are specifically after this,” stated tom. “they’ll steal any new invention they can. but from the fact that hussy was in here i judge they must have heard something about the air monarch and they want to get an idea of how she’s made. i suspected they might try something like this, and so i set several traps. hussy happened to step into one,” and taking ned to the various windows tom showed other devices to nab intruders.

going over the machine and making an examination of the workshop in company with ned, convinced tom that hussy had been caught before he could do any damage.

“but from now on i’ll have to be doubly careful,” tom declared. “and if i see hussy around here again——” he did not finish, but it could easily be guessed what would happen.

from then on it became increasingly difficult for strangers to get near the swift plant. eradicate and koku were kept on guard in the shop where the air monarch was housed and mr. swift, with a smile, said they at times even looked on him with suspicion.

but the days passed and the big machine was practically completed, and then came a trial flight which was successful. the giant craft took the air like a bird, and though its speed was not quite up to tom’s expectations, he said that with some adjustments he thought it would beat any aircraft he had ever made.

on land the progress was necessarily slower, and in the water it was slower still. but even at that the air monarch did well, and it could do still better, tom declared.

the machine was taken back to the shop for some final adjustments, and tom was busy superintending these one day when ned newton burst into the building, waving a paper over his head and exclaiming:

“look at this, tom! listen to this! you’ve got a chance to make a fortune!”

“i sure need it,” said the young inventor, with a smile. “this machine is costing a lot more than we’d figured on. but what’s the idea? has some one left me a million?”

“no,” answered ned. “but this paper, the new york illustrated star, offers a prize of one hundred thousand dollars for an international race around the world in the shortest time—actual time. why, tom, those are exactly the conditions under which your father wagered with burch and trace! why don’t you go in for this?”

“maybe i will,” said tom. “let’s have a look!”

eagerly he read the story in the paper, setting forth the terms of the prize offer. they were simple enough.

at a date about a month off, any person who wished to contest must start from an aero field on long island. the first person to return to the starting point, after actually circling the globe, would be given a hundred thousand dollars.

there were no conditions except that all contestants must prove by documentary evidence, such as having signed statements from officials in various countries, that they had passed through or over them on certain dates. the world must be girdled on a circle of one of its great circumferences, that is the equator, or a parallel not too far above or below it. or, if a contestant desired, he could circle around a longitudinal line. but as this would mean flying over the north and south poles, that was practically out of the question. it was assumed that those who took part would travel along about the fortieth parallel, as this would keep them over fairly civilized countries for the longest period.

contestants could travel as they liked, in any sort of conveyance, motor car, steamer, train, airship, or submarine. they could change conveyances as often as they pleased. the sole requisite was that they must come back to the starting point, after traveling completely around the earth, and they must prove that they had done it.

“this suits me!” exclaimed tom, as he read the conditions.

“then you’ll enter for the hundred thousand dollars?” asked ned.

“i certainly will, and i hope to win it. now this race is going to be worth while. if i won the twenty thousand dollars for dad, i’d hardly break even. but if i win the prize—oh, boy!” and tom patted the big machine into which his hopes were built.

keyed up to a high pitch by the prospect, tom hurried his mechanics and helpers to the limit. not any too much time was left to enter the illustrated star’s contest, and within a few days tom swift’s entry had been formally sent in and acknowledged.

each succeeding day’s issue of the paper gave tom and ned news of the event, and one day tom pointed to an item in the general story.

“the red arrow people are going to try for the prize,” he said. “they’re going to fight me. that’s why hussy was sneaking in here, i guess. they wanted to see if they could add anything to the aeroplane they are going to enter.”

“are they going to try in an aeroplane?” asked ned.

“so it says here. it doesn’t mention any boat or automobile auxiliary.”

tom had been obliged to describe the method he proposed to follow in the world race, and of course it was publicly known now that he would try in a combined automobile, motor boat, and aeroplane. aside from some hydroplanes, which of course can skim along on the surface of the water, as well as soar over land, tom’s was the only machine of more than a single ability.

many of the contestants, of which there seemed likely to be plenty, at least at the start, were going to make the attempt by special steamers or trains, for not a few wealthy globetrotters entered the contest for the big purse.

it lacked about a week of the time of the start of the international race when one morning tom swift received a telegram. it was signed by a name he did not at first recognize, that of armenius peltok, and read:

“if you are going to enter international world race i shall be honored if you will take me with you. i speak all civilized languages and some uncivilized, and am also an aircraft mechanic. reference the national aero club.”

“another crank,” murmured ned.

“i don’t know about that,” voiced tom. “it’s worth looking up. see if you can get the aero club on the wire.”

when ned had done so and had been told that peltok, though little known in america, had a great reputation in europe and was thoroughly reliable, a message was sent asking him to call at the swift plant. peltok had wired from new york. a day later he telephoned that he would be with tom very shortly.

“we need another good man,” tom said to ned.

“how many are going?”

“five.”

“well, who are the other two besides you, peltok, and me?”

“i haven’t decided yet, but i have my eye on a couple of young fellows. now let’s see what we have next to do.”

“there’s plenty,” stated ned, with truth.

the work went along. the air monarch was fully equipped for the race, and another trial flight showed big improvement as regarded her three speeds, on land, water, and in the air. night and day men were on guard now, to keep tom’s secret of his craft. though in general its character was known, there were many things about it that the inventor did not want to reveal.

meanwhile, the plan of an international world race was meeting with favor on all sides. though one paper had offered the prize, the other journals gave plenty of space to the event and excitement was at a high pitch. some wild and rash schemes were talked of, and not a few new and queer machines, both for land, air and water travel were entered. one man proposed to go in a motor car, hiring speedy, small steamers when land failed him, to transport his machine.

peltok arrived and created a favorable impression on tom and ned. he was a quiet, reserved man, of great muscular strength, and he knew travel machines from end to end.

“and he can speak anything!” declared ned. “he even talked to koku in the giant’s own language.”

“no!” cried tom.

“fact! you ask koku.”

tom confirmed ned’s statement. peltok was a great linguist, and it was felt this accomplishment would be valuable should the air monarch have to land in uncivilized countries.

a few days before the air monarch was to leave for long island, ned came to tom with rather a serious face.

“we need more money, tom, to complete the stocking of the ship and arranging for carrying on the business here while you are gone,” said the financial manager.

“get it from the bank,” said tom.

“we can’t. we’ve stretched our credit to the limit. we need ten thousand dollars in cash.”

for a moment tom did not know what to do. then he remembered his millionaire friend jason jacks, who had helped him on the airline express in a like emergency.

“call jacks,” tom decided. when ned did this, explaining tom’s predicament, that eccentric, but kindly, character at once arranged the matter, sending, not ten, but fifteen thousand dollars to the credit of the swift company in the bank.

“and if you want more you can have it,” added mr. jacks. but ned said that would do.

“well, i go to new york to-morrow,” said tom to ned one evening, “to sign the final papers in the race contest. all contestants are to be present in the illustrated star office.”

“where are you going now?” asked ned, for his chum had on his hat and the electric runabout was at the door.

“over to see mary,” was the answer.

a little later tom swift was on his way. but for some reason or other, when he was within a quarter of a mile of the girl’s house, the electric machine suddenly went dead and stopped.

“that’s queer!” mused tom, as he got out of the stalled car to have a look. “i thought the batteries were fully charged. some one must have been running it without telling me. well, i can walk, i suppose. it isn’t far.”

he tested the storage batteries, found that his surmise was correct—that they had exhausted themselves, though unaccountably—and then he started to walk.

but he had not gone far along the road, which was very lonely at this point, when a dark figure sprang suddenly from the bushes, leaped toward the young inventor, and uttered a smothered imprecation. there was a dull, thudding blow, and tom was stricken down, sinking unconscious in the long grass at the side of the highway. then the dark figure, with a sinister chuckle, fled amid the shadows of the night.