"It's a young man," answered the driver.

"Is he acquainted around here?" went on the voice from the rear of the car. "Ask him if he is acquainted around here, Simpson."

Tom was wondering where he had heard that voice before. He had a vague notion that it was familiar.

"Are you acquainted around here?" obediently asked the man at the wheel.

"I live here," replied Tom.

"Ask him if he knows any one named Swift?" continued the voice from the tonneau, and the driver started to repeat it.

"I heard him," interrupted Tom. "Yes, I know a Mr. Swift;" but Tom, with a sudden resolve, and one he could hardly explain, decided that, for the present, he would not betray his own ident.i.ty.

"Ask him if Mr. Swift is an inventor." Once more the unseen person spoke in the voice Tom was trying vainly to recall.

"Yes, he is an inventor," was the youth's answer.

"Do you know much about him? What are his habits? Does he live near his workshops? Does he keep many servants? Does he--"

The unseen questioner suddenly parted the side curtains and peered out at Tom, who stood in the muddy road, close to the automobile. At that moment there came a bright flash of lightning, illuminating not only Tom's face, but that of his questioner as well. And at the sight Tom started, no less than did the man. For Tom had recognized him as one of the three mysterious persons in the restaurant, and as for the man, he had also recognized Tom.

"Ah--er--um--is--Why, it's you, isn't it?" cried the questioner, and he thrust his head farther out from between the curtains. "My, what a storm!" he exclaimed as the rain increased. "So you know Mr. Swift, eh? I saw you to-day in Mansburg, I think. I have a good memory for faces. Do you work for Mr. Swift? If you do I may be able to--"

"I'm Tom Swift, son of Mr. Barton Swift," said Tom as quietly as he could.

"Tom Swift! His son!" cried the man, and he seemed much agitated.

"Why, I thought--that is, Morse said--Simpson, hurry back to Mansburg!" and with that, taking no more notice of Tom, the man in the auto hastily drew the curtains together.

The chauffeur threw in the gears and swung the ponderous machine to one side. The road was wide, and he made the turn skilfully. A moment later the car was speeding back the way it had come, leaving Tom standing on the highway, alone in the mud and darkness, with the rain pouring down in torrents.

CHAPTER VII.

OFF ON A SPIN

Tom's first impulse was to run after the automobile, the red tail-light of which glowed through the blackness like a ruby eye. Then he realized that it was going from him at such a swift pace that it would be impossible to get near it, even if his bicycle was in working order.

"But if I had my motor-cycle I'd catch up to them," he murmured. "As it is, I must hurry home and tell dad. This is another link in the queer chain that seems to be winding around us. I wonder who that man was, and what he wanted by asking so many personal questions about dad?"

Trundling his wheel before him, with the chain dangling from the handle-bar, Tom splashed on through the mud and rain. It was a lonesome, weary walk, tired as he was with the happenings of the day, and the young inventor breathed a sigh of thankfulness as the lights of his home shone out in the mist of the storm. As he tramped up the steps of the side porch, his wheel b.u.mping along ahead of him, a door was thrown open.

"Why, it's Tom!" exclaimed Mrs. Baggert. "Whatever happened to you?"

and she hurried forward with kindly solicitude, for the housekeeper was almost a second mother to the youth.

"Chain broke," answered the lad laconically. "Where's dad?"

"Out in the shop, working at his latest invention, I expect. But are you hurt?"

"Oh, no. I fell easily. The mud was like a feather-bed, you know, except that it isn't so good for the clothes," and the young inventor looked down at his splashed and bedraggled garments.

Mr. Swift was very much surprised when Tom told him of the happening on the road, and related the conversation and the subsequent alarm of the man on learning Tom's ident.i.ty.

"Who do you suppose he could have been?" asked Tom, when he had finished.

"I am pretty certain he was one of that crowd of financiers of whom Anson Morse seems to be a representative," said Mr. Swift. "Are you sure the man was one of those you saw in the restaurant?"

"Positive. I had a good look at him both times. Do you think he imagined he could come here and get possession of some of your secrets?"

"I hardly know what to think, Tom. But we will take every precaution. We will set the burglar alarm wires, which I have neglected for some time, as I fancied everything would be secure here. Then I will take my plans and the model of the turbine motor into the house. I'll run no chances to-night."

Mr. Swift, who was adjusting some of the new bolts that Tom had brought home that day; began to gather up his tools and material.

"I'll help you, dad," said Tom, and he began connecting the burglar alarm wires, there being an elaborate system of them about the house, shops and grounds.

Neither Tom nor his father slept well that night. Several times one or the other of them arose, thinking they heard unusual noises, but it was only some disturbance caused by the storm, and morning arrived without anything unusual having taken place. The rain still continued, and Tom, looking from his window and seeing the downpour, remarked:

"I'm glad of it!"

"Why?" asked his father, who was in the next room.

"Because I'll have a good excuse for staying in and working on my motor-cycle."

"But you must do some studying," declared Mr. Swift. "I will hear you in mathematics right after breakfast."

"All right, dad. I guess you'll find I have my lessons."

Tom had graduated with honors from a local academy, and when it came to a question of going further in his studies, he had elected to continue with his father for a tutor, instead of going to college.

Mr. Swift was a very learned man, and this arrangement was satisfactory to him, as it allowed Tom more time at home, so he could aid his father on the inventive work and also plan things for himself. Tom showed a taste for mechanics, and his father wisely decided that such training as his son needed could be given at home to better advantage than in a school or college.

Lessons over, Tom hurried to his own particular shop, and began taking apart the damaged motor-cycle.

"First I'll straighten the handle-bars, and then I'll fix the motor and transmission," he decided. "The front wheel I can buy in town, as this one would hardly pay for repairing." Tom was soon busy with wrenches, hammers, pliers and screw-driver. He was in his element, and was whistling over his task. The motor he found in good condition, but it was not such an easy task as he had hoped to change the transmission. He had finally to appeal to his father, in order to get the right proportion between the back and front gears, for the motor-cycle was operated by a sprocket chain, instead of a belt drive, as is the case with some.

Mr. Swift showed Tom how to figure out the number of teeth needed on each sprocket, in order to get an increase of speed, and as there was a sprocket wheel from a disused piece of machinery available, Tom took that. He soon had it in place, and then tried the motor. To his delight the number of revolutions of the rear wheel were increased about fifteen per cent.

"I guess I'll make some speed," he announced to his father.

"But it will take more gasolene to run the motor; don't forget that.

You know the great principle of mechanics--that you can't get out of a machine any more than you put into it, nor quite as much, as a matter of fact, for considerable is lost through friction."

"Well, then, I'll enlarge the gasolene tank," declared Tom. "I want to go fast when I'm going."

He rea.s.sembled the machine, and after several hours of work had it in shape to run, except that a front wheel was lacking.

"I think I'll go to town and get one," he remarked. "The rain isn't quite so hard now."