“Don’t let him pass,” she implored them desperately.  “It’s our criminal, Sergeant Mullins!  Don’t you see?  The gambler!”

But Sergeant Mullins, in one swift glance, had already taken in the situation, and as the man tried to start his machine he sprang forward and grasped the handle bars, at the same time shouting orders to his men.

“Surround him, fellows!” he cried.  “This man is under arrest!”

“What do you mean?” cried the gambler, his eyes glaring with the rage of a cornered animal.

“Don’t waste your breath, Denham,” retorted Sergeant Mullins coolly, “your reputation isn’t any too good around these parts, you know, and you’ll have plenty of chance to do your shouting to the judge.

“Never mind your machine,” he added sharply, as the fellow’s mean eyes glanced about desperately for means of escape.  “The boys will take care of that.  And,” he added meaningly, “I have rather a life-sized impression that you won’t be needing it again for some time to come!”

Denham shot him a vicious glance, and got off sullenly from his machine while a group of soldiers stepped up smartly to take charge of it.

With his prisoner safely guarded, Sergeant Mullins ordered the march back to camp, then drew in a long breath and looked at the girls.

“Well,” he said, with his slow smile, “you did it that time.”

“We!” cried Betty, her cheeks flushed with excitement and the exhilaration of success.  “I should say you did the work while we looked on.  Oh, I’m so happy—­and so grateful to you.”

“But I didn’t do anything,” he protested, smiling whimsically, as they turned to follow the soldiers and their prisoner.  “I simply let the boys do the work while I looked on.”

“Goodness! what do we care how it happened as long as it did?” cried Mollie happily.  “Maybe now he’ll see that he can’t run down old ladies promiscuously and get away with it.”

“Not with girls like you on his trail,” said the sergeant admiringly.

“But what are you going to do with him, now you’ve got him?” asked Grace, repeating almost word for word the question Mollie had put only a few minutes before.  “I suppose we’ve got to get out some sort of definite charge against him.”

“Yes,” said the sergeant thoughtfully.  “We can put him in the guardhouse up at camp till we have a chance to get the township authorities up here.  And,” he added, turning to Betty, “I’d like to have an interview with that old lady of yours, if you can manage it.  We’ll have to have her evidence, you know.”

“Oh, and isn’t it lucky?” cried Betty, executing a little skip in her excitement.  “She told us only this morning that she was feeling perfectly well again and would go away to-morrow.  We were worrying ourselves sick about it, but couldn’t think up a single plan to keep her with us.  And if she had gone before this happened—­” she stopped, overwhelmed by the mere contemplation of the tragedy.