“Humph, that sounds all right,” observed Mollie.  “But has any one here any suggestion as to just how we will go about it?  I’m sure I don’t know any one who is acquainted with Professor Dempsey—­ or his family either.”

“I’ve got it,” said Betty, leaning forward eagerly.  “It may not be much of an idea, but then again it may.”

“Speak up, speak up, what’s on your mind?” urged Mollie slangily.

“Well,” said Betty, “there is Mr. Haig, principal of Deepdale High.  He knows pretty nearly every one at the university where Professor Dempsey used to teach and he is more than likely to know whether the professor has any sons and what their names are.”

“Yes, that is all right as far as it goes,” broke in Mollie impatiently.

“We all know Mr. Haig—­” Amy began, but this time it was Grace who interrupted.

“Yes, we all know him,” she said.  “But I’d like to know if there is any one of us—­ except Betty perhaps—­ who would have the nerve to go to him and ask him a question like that——­”

“Say, who’s telling this story I’d like to know,” broke in Betty impatiently.  “I’m not asking any one to go to Mr. Haig with that question or any other—­ although I would be perfectly willing to brave the lion in his den if there were no other way.  My plan is this.  Dad knows Mr. Haig, you know—­ went to school with him—­ old college chums and all that.  I’m sure that if we asked him real pretty he would go to Mr. Haig and find out about Professor Dempsey for us.”

“Then suppose we find out that Professor Dempsey hasn’t any sons by the name of James and Arnold?” suggested Grace.

“Then we shall be mighty glad we took the trouble to find out and set our minds at rest,” answered Betty soberly.

“And if we find out that they are really his sons, what then?” queried Grace, and this time Betty looked puzzled and Mollie and Amy completely beyond their depth.

“Why then,” said Betty hesitatingly, “I’m sure I don’t just know what we ought to do.  But don’t you think,” she added, brightening, “that it might be a good idea to wait until we have found out definite facts before we try to solve any more problems?”

Rather reluctantly the girls agreed and, after making Betty promise that she would let them know the very first minute she found out the names of Arnold Dempsey’s sons, they said good-bye and started for home.

Of course Betty had already told her father and mother about Professor Dempsey and the part he had played in actually saving their lives; so when she told them that night of what she had read in the paper and begged her father to help her find out whether the dead soldiers were really Arnold Dempsey’s sons or not, he readily consented to do what he could.

“I’ll drop in and see Haig to-morrow,” he promised.  “I have often heard him speak of Professor Dempsey as being one of the best professors of zoology up at the university and I am sure I will be able to find out what you want to know.  I hope you have been mistaken in your conclusions, for it would be a horrible blow to a man to lose both his grown sons at once and like that.  Now run off to bed and tomorrow I may have some news for you.”