The fact that he was stopped by a footpad smote Tom Swift's mind as not a particularly surprising adventure. He had heard that several of that gentry had been plying their trade about the outskirts of the town. To a degree he was prepared for this sudden event.

Then there flashed into Tom's mind the thought of what Mr. Richard Bartholomew had said regarding the spy he believed had followed him from the West. Could it be possible that some hired thug sent by Montagne Lewis and his crooked crowd of financiers considered that Tom Swift had obtained information from the president of the H. & P. A. that might do his employers signal service?

Tom Swift had fallen in with many adventures--and some quite thrilling ones--since, as a youth, he was first introduced to the reader in the initial volume of this series, entitled "Tom Swift and His Motor Cycle." His first experiences as an inventor, coached by his father, who had spent his life in the experimental laboratory and workshop, was made possible by his purchase from Mr. Wakefield Damon, now one of his closest friends, of a broken- down motor cycle.

Through a series of inventions, some of them of a marvelous kind, Tom Swift, aided by his father, had forged ahead, building motor boats, airships, submarines, monoplanes, motion picture cameras, searchlights, cannons, photo-telephones, war tanks. Of late, as related in "Tom Swift Among the Fire Fighters," he had engaged in the invention of an explosive bomb carrying flame- quenching chemicals that would, in time, revolutionize fire- fighting in tall buildings.

The matter that Mr. Richard Bartholomew, the railroad magnate, had brought to Tom's and his father's attention had deeply interested the young inventor. Thought of the electric locomotive, the development of which the railroad president stated was the only salvation of the finances of the H. & P. A., had so held Tom's attention as he walked along the street that being stopped in this sudden way was even more startling than such an incident might ordinarily have been.

Tom was a muscular young fellow; but a club held over one's head by a burly thug would have shaken the courage of anybody. Dark as it was under the archway the young fellow saw that the bulk of the man was much greater than his own.

"That's right, sonny," said the stranger, in a sneering tone. "You got just the right idea. When I say 'Stick 'em up' I mean it. Never take a chance. Ah--ah!"

The fellow ripped open Tom's overcoat, almost tearing the buttons off. Another masterful jerk and his victim's jacket was likewise parted widely. He did not lower the club for an instant. He thrust his left hand into the V-shaped parting of the young fellow's vest.

It was then that Tom was convinced of what the fellow was after. He remembered the notes he had made regarding the contract that was to be signed on the morrow between the Swift Construction Company and President Richard Bartholomew of the H. & P. A. Railroad. He remembered, too, the figure he thought he had seen in the dark porch of the house as he so recently left it.

Mr. Bartholomew had considered it very possible that he was being spied upon. This was one of the spies--a Westerner, as his speech betrayed. But Tom was suddenly less fearful than he had been when first attacked.

It did not seem possible to him that Mr. Bartholomew's enemies would allow their henchman to go too far to obtain information of the railroad president's intentions. This fellow was merely attempting to frighten him.

A sense of relief came to Tom Swift's assistance. He opened his lips to speak and could the thug have seen his face more clearly in the dark he would have been aware of the fact that the young inventor smiled.

The fellow's groping hand entered between Tom's vest and his shirt. The coarse fingers seized upon Tom's wallet. Nobody likes to be robbed, no matter whether the loss is great or small. There was not much money in the wallet, nor anything that could be turned into money by a thief.

These facts enabled Tom, perhaps, to bear his loss with some fortitude. The highwayman drew forth the wallet and thrust it into his own coat pocket. He made no attempt to take anything else from the young inventor.

"Now, beat it!" commanded the fellow. "Don't look back and don't run or holler. Just keep moving--in the way you were headed before. Vamoose."

More than ever was Tom assured that the man was from the West. His speech savored of Mexican phrases and slang terms used mainly by Western citizens. And his abrupt and masterly manner and speech aided in this supposition. Tom Swift stayed not to utter a word. It was true he was not so frightened as he had at first been. But he was quite sure that this man was no person to contend with under present conditions.

He strode away along the sidewalk toward the far corner of the wall that surrounded this estate. Shopton had not many of such important dwellings as this behind the wall. Its residential section was made up for the most part of mechanics' homes and such plain but substantial houses as his father's.

Prospering as the Swifts had during the last few years, neither Tom nor his father had thought their plain old house too poor or humble for a continued residence. Tom was glad to make money, but the inventions he had made it by were vastly more important to his mind than what he might obtain by any lavish expenditure of his growing fortune.

This matter of the electric locomotive that had been brought to his attention by the Western railroad magnate had instantly interested the young inventor. The possibility of there being a clash of interests in the matter, and the point Mr. Bartholomew made of his enemies seeking to thwart his hope of keeping the H. & P. A. upon a solid financial footing, were phases of the affair that likewise concerned the young fellow's thought.

Now he was sure that Mr. Bartholomew was right. The enemies of the H. & P. A. were determined to know all that the railroad president was planning to do. They would naturally suspect that his trip East to visit the Swift Construction Company was no idle jaunt.

Tom had turned so many fortunate and important problems of invention into certainties that the name of the Swift Construction Company was broadly known, not alone throughout the United States but in several foreign countries. Montagne Lewis, whom Tom knew to be both a powerful and an unscrupulous financier, might be sure that Mr. Bartholomew's visit to Shopton and to the young inventor and his father was of such importance that he would do well through his henchmen to learn the particulars of the interview.

Tom remembered Mr. Bartholomew's mention of a name like Andy O'Malley. This was probably the man who had done all that he could, and that promptly, to set about the discovery of Mr. Bartholomew's reason for visiting the Swifts.

Without doubt the man had slunk about the Swift house and had peered into one of the library windows while the interview was proceeding. He had observed Tom making notes on the scratch pad and judged correctly that those notes dealt with the subject under discussion between the visitor from the West and the Swifts.

He had likewise seen Tom thrust the paper into his wallet and the wallet into his inside vest pocket. Instead of dogging Mr. Bartholomew's footsteps after that gentleman left the Swift house, the man had waited for the appearance of Tom. When he was sure that the young fellow was preparing to walk out, and the direction he was to stroll, the thug had run ahead and ensconced himself in the archway on this dark block.

All these things were plain enough. The notes Tom had taken regarding the offer Mr. Bartholomew had made for the development of the electric locomotive might, under some circumstances, be very important. At least, the highwayman evidently thought them such. But Tom had another thought about that.

One thing the young inventor was convinced about, as he strode briskly away from the scene of the hold-up: There was going to be trouble. It had already begun.