fraction of a second at which it is hit. The bullet strikes another wire as it goes through the second hoop and this also registers. Then all they have to do is to subtract the first time from the second and they have the exact time it has taken for the bullet to go that two hundred feet.”

“Seems simple enough when you come to think of it,” remarked Tom.

“Then,” went on Joe, “it struck somebody that it would be perfectly easy to rig up a couple of hoops sixty feet apart and let a pitcher hurl a straight ball through both and then measure the different times at which it struck the two hoops. They did it down at some Connecticut plant and got two of the swiftest pitchers in the big leagues to try out their speed. One of them put it through at the rate of one hundred and twelve feet a second and the other at the rate of one hundred and twenty-two feet a second. That’s why I said that that last ball of mine was going at over a hundred feet a second.”

“Guess you knew what you were talking about, old boy,” said Tom, as he walked back to take his place again at the receiving end. “But after this, cut down the speed to eighty or thereabouts. That’ll be rich enough for my blood at present.”

“All right,” grinned Joe. “We’ll cut out the fast straight ones and work out a few of the curves.”

“Just what do you mean by curves?” asked a rather gruff voice.

Joe turned and recognized Professor Enoch Crabbe of the Riverside Academy, who had been strolling by, and having caught a glimpse of the unusual number present through the open door, had concluded to add himself to the spectators. He was a man generally respected in the town, but very positive and set in his views and not at all diffident about expressing them.

“Good afternoon, Professor,” said Joe. “I didn’t quite understand what you meant by your question. I was just going to curve the ball——”

“That’s just it,” interrupted the professor with a superior smile. “You thought you were going to curve the direction of the ball, but you were going to do nothing of the kind. It can’t be done.”

“But Professor,” expostulated Joe, a little bewildered, “the proof of the pudding is in the eating. I’ve done it a thousand times.”

“I don’t question your good faith at all, Mr. Matson,” said the professor, still with that smug air of certainty. “You undoubtedly think you curved the ball. I positively know that you didn’t.”

“Well,” retorted Joe, who was getting a little nettled, “they say that seeing is believing. Just watch this ball.”

He gripped it firmly and sent in a wide outcurve. The ball went straight as a die for perhaps forty feet and then turned swiftly outward so that Tom had to jump to get his hands on it.

“Now,” said Joe triumphantly, “if that wasn’t a curve, what was it?”

“An optical delusion,” replied the professor blandly.

“If a batter had been at the plate, he’d have broken his back reaching out after it,” Joe came back at him. “He wouldn’t have thought it was an optical delusion.”

“My dear sir,” said the professor smoothly, “the first law of motion is that a body set in motion tends to move in a straight line. Neither you nor anybody else can change that law. You might as well tell me that you can shoot a gun around a corner as that you can throw a ball around a corner.”

“I can throw it around the corner,” maintained Joe stoutly. “Not at right angles, of course, but I can make the ball go into the side street.”

The theorist smiled in a way that was exceedingly irritating. But Joe, by a great effort, mastered his annoyance.

“We won’t quarrel over it, Professor,” he remarked good-naturedly. “All I can say is that I must be getting my salary under false pretences, because the men who pay it to me do so under the impression that I can curve the ball. I’ve always had that impression myself, and so have the batters who have faced me. Rather odd, don’t you think, that so many people should be so misled?”

“Not at all,” replied the professor pompously. “Truth is usually on the side of the minority.”

“I’ll tell you what I’ll do,” said Joe thoughtfully. “I know a moving picture operator, who’s an old friend of mine and who’d be glad, if I asked him, to do me a favor. I’ll get him to come down some day and take a picture of the ball in motion. Then we’ll study out the film and I think I can prove to you that the ball does curve on its way from the pitcher to the catcher.”

“How do you think you could prove anything from that?” asked Professor Crabbe cautiously, as though he were looking for a trap. “They can work all sorts of tricks with moving pictures, you know.”

“I know they can,” admitted Joe. “But this would be ‘honest Injun.’ You’d have my word of honor and the operator’s, too, that there’d be no monkeying with the pictures.”

“Well,” said Crabbe, “admitting that the pictures were honestly taken, how could they show whether the ball curved or not?”

“I’m not sure myself exactly,” answered Joe, “but it seems to me that if the ball moved in a straight line all the way, it would look the same at any point. But if it curved, it would be farther away from the camera than when it was going straight and there’d be a different focus. The ball would look flatter, more oval shaped——”

Just then came a wild diversion.

Into the gymnasium crowd burst a shock-headed boy, his eyes blazing with excitement, his breath coming in gasps. All looked at him in astonishment and alarm.

“A crazy man,” stammered the boy. “He’s stolen the Bilkins baby and run off with it!”

CHAPTER II
A FEARFUL SITUATION

There was a general gasp of horror mixed with unbelief.

“What do you mean?” demanded Sam Berry.

“Where did you get that yarn?” asked Ed Wilson.

“It’s true,” declared the boy. “The whole town’s hunting for him. He ran into Mrs. Bilkins’ house and snatched the baby from the cradle. The man was bareheaded and didn’t have any coat. Mrs. Bilkins ran after him, screaming, but she couldn’t catch him and——”

But the rest of the lad’s story fell on deaf ears. Joe and Tom and the others had already slipped into their coats, and now they poured pell-mell out of the door, each of them eager to be first on the scene and rescue the kidnapped baby before the madman could do it harm.

They all knew and liked Bilkins, who was a bright young fellow employed in the Harvester works. Three years before he had married and brought his bride to a pretty little cottage at the southern edge of the town. Their one baby was now nearly a year old and of course the young parents were wrapt up in him.

Joe and his sister Clara had often spent a pleasant evening at the Bilkins home, and the heart of the young pitcher was hot within him as he raced in that direction, while his sympathy gave wings to his feet.

A light snow had fallen and this would have been of some assistance in tracing the marauder, but so many people had by this time joined in the hunt that many trails led in as many different directions.

Joe and Tom were circling wildly around, like hounds trying to pick up a lost scent, when a little fellow ran up to them.

“I saw him!” he cried, “a big, tall man carrying a baby! He was going down to the