“Good afternoon,” he called to them, with the smile that always so surprisingly lighted up his usually grave face.  “You look as if you had had rather an exciting time of it.”

“Oh, we did almost have such a beautiful adventure!” cried Mollie, her eyes sparkling with the memory of it.

“And all we really got,” said Grace gloomily, “were four pairs of sore feet.”

Sergeant Mullins laughed at her with the rest, then asked, with real interest: 

“But the adventure that you almost had,—­would you mind telling me about it?”

Whereupon Betty launched into a full and graphic account of the chase in somebody else’s automobile after an unknown criminal who, at the last minute, had escaped in an apparently impossible manner.

“And that’s all there is to it,” she finished plaintively.  “After all our trouble and everything, we find ourselves just where we were before.”

The sergeant looked very grave.

“The man was a cad,” he said, “to knock down an old woman that way and then not stop to see how badly she was hurt.  I wish you could have won out to-day.  Could you give a good description of him?”

“Yes, I can,” cried both Amy and Grace in the same breath, and thereupon proceeded to do it without delay.  At the description the sergeant’s interest grew and his face flushed with excitement.

When they had finished, Betty, who had been watching his face closely, unable to restrain her curiosity longer, burst forth an eager question.

“Have you seen the man, Sergeant?”

“I think I have—­often,” he replied slowly, adding as they turned incredulous eyes upon him.  “If I’m not mistaken, this criminal of yours is one of the most famous card sharpers of the day.”

CHAPTER XXII

STARTLING DEVELOPMENTS

For a moment the girls stared.  Then Sergeant Mullins was besieged with a veritable flood of questions.

“He hangs out mostly at Thomasville, a town about fifteen miles from here,” the sergeant explained, when at last the girls had realized that if they ever hoped to learn anything at all they must give the man a chance to speak.  “And he makes most of his money by skinning the rookies.”

“You mean,” cried Betty, translating camp slang into intelligible English, “that he gets the newly enlisted men to play with him before they have a chance to learn his reputation, and of course gets all their money, because his game is crooked?”

“Exactly,” agreed Sergeant Mullins, his grave face clouding angrily.  “And equally, of course, it’s the week following pay day when he makes his big haul.  I hope you succeed in getting him,” he said, turning earnestly to Betty.  “And if there’s anything I can do to help, you can count on me.”

Betty thanked him, and the girls watched the Sergeant’s straight, retreating back with thoughtful eyes.