believe is my sister. And the part that is most interesting——"

"Is where——" began Will.

"Can't you keep still?" begged his sister.

"Has 'oo dot any tandy?" and he imitated little Dodo.

"Oh, take that!" and Grace passed him a caramel. "Now, let's hear what it is, Mr. Blackford."

"There is a part of the letter which says this," went on Mr. Blackford, and he proceeded to read:

"'You can always identify the girl because she has a most peculiar birth-mark on——'"

He ceased reading.

"Well, go on, please," requested Betty. "This is getting interesting."

"It isn't getting interesting—it's so already," declared Mollie. "Go on, please, Mr. Blackford, tell us what sort of birth-mark your sister has."

"That's just the trouble," he remarked, ruefully. "I can't do it."

"Why not?" Betty wanted to know.

"Because, just at that point—where the description of the birth-mark, and its location, should appear—the letter is torn. A corner is gone. I have no more idea of what sort of identifying mark my sister has, than have you. It is worse than before, for I saw hope ahead of me, only to see it disappear now.

"I feel sure that the girl referred to in the old letter is my sister; but how can I identify her, in case I meet her, until I know what sort of a mark she has, and where it is?"

"You can't!" declared Will, positively.

"And that makes it all the more tantalizing," went on Mr. Blackford. "They even—that firm I spoke of—they even had located the part of the country where it might be possible my sister was, and now to have it fail this way——"

"Where did they say she might be?" asked Amy.

"Somewhere up in Canada. But it is rather vague. If only that piece was not torn off the edge of the letter!"

"Can't you find it somewhere?" asked Mollie. "Maybe in forwarding it the people you hired tore it by accident."

"I thought of that, so I telephoned as soon as I got this letter, asking where the missing piece was. I got word back that they knew nothing about it."

There was silence for a moment, while they all looked at the mutilated document Mr. Blackford held up. It showed a tear across one corner, a tear that disposed of the most vital piece of information contained on the whole paper.

"That's too bad," spoke Amy, sympathetically.

"Yes," agreed Mollie, as she put back a stray and rebellious lock of hair, "it spoils all your plans, I suppose, Mr. Blackford."

"In a way, yes. But I'm not going to give up. I'm going to find out where they got this document from, and go there. It may have been in some old attic trunk, among some—love letters—and the missing piece may be there."

"Without it you're all at sea," declared Will. "You don't know what sort of a mark to look for, nor where it might be."

"And he can't very well go around asking all the girls he meets if they have peculiar birth-marks," commented Mollie.

"Well, I hardly know why I told you my troubles," said the young man, "but——"

"Why shouldn't you?" asked Betty, pleasantly. "We are interested in you, of course, ever since——"

"That five hundred dollar bill you thought was gone for good," added Amy. "But if we hear of anything——" and she paused suggestively.

"I wish you'd let me know!" exclaimed Mr. Blackford. "I know you girls are very lucky. You've proved it several times. Now if you happen to hear of anyone who would fit what description I have of my sister—and it isn't much, to tell the truth—or if you think you see anyone who resembles me, or who has a peculiar birth-mark, just let me know. You travel around so much, and you meet so many strange people——"

"We do seem to," agreed Grace.

"Well, just let me know," finished Mr. Blackford.

For some little time they talked of the curious happening, and the perversity of fate that should provide for such a vital piece of the letter being missing. Then, after Amy had provided refreshments, the young men and girls prepared to take their leave.

"And you and Mollie won't forget to find out for sure if you can go to the lumber camp; will you, Betty?" asked Grace. "Let me know as soon as you can."

"I'll call you up first thing in the morning," promised Betty. "I'm pretty sure I can go. Oh! what fun we'll have!"

"Any skating there?" asked Mr. Blackford.

"Oceans of it!" said Grace, who had asked her father many questions about the camp they expected to visit.

"How about ice boating?" inquired Will.

"You can have that, too. There isn't an ice boat in camp, father said, but not far away a man has a sort of winter bungalow, and he keeps a number. Maybe he'll lend us one."

"And can you run it?" asked Amy, timidly.

"It runs itself—you just sit in it and the wind blows it along. All you have to do is steer," said Grace.

"You're getting to be quite an authority," declared Mollie. "Oh, but I know we'll have a fine time!"

"And we'll come up too, sometimes," put in Will. "That is, if you girls will let us."

"Of course," murmured Mollie. "Isn't that the telephone ringing, Grace?" for they were all on the front steps.

"Yes. I'll see who it is," said Amy. "Maybe they want one of you girls. Wait!"

"Can't have any of 'em—all taken," declared Will.

"It's you they want, Mollie," reported Amy, coming back. "It's your mother, and she seems to be in trouble."

"Trouble?" Mollie's voice trembled.

"Yes. Oh, dear! I'm sure she was crying!" and Amy's voice faltered, for she was very tender-hearted.

Mollie went to the telephone. The others listened anxiously for an inkling of what the message might be.

"What!" cried Mollie. "Paul missing—he must have gone out right after I did! Oh, dear! And it's beginning to snow!"

"Girls!" she cried, turning to the others, and letting the receiver fall with a bang, "little Paul is missing—mother thinks he went out of doors. Oh, that poor child!"

CHAPTER V

UNPLEASANT NEWS

Will was the first to realize the import of the message. He exclaimed briskly:

"Gone out; eh? Well, it won't be hard to track him, for there is a light, new covering of snow on the ground and sidewalks. That is, if we get right at it. Come on, Mr. Blackford, and we'll find the little rascal!"

"Of course we will!" cried Betty. "Don't cry, Mollie dear. He can't be lost for long; everyone in Deepdale knows him and whoever finds him will take him home."

"Yes, but he—he may freeze!"

"Oh, it isn't cold!" declared Grace, though she was even then shivering. Grace was not any too well built to stand cold weather.

"That's it! Stick to it!" whispered Will in her ear. "Insist that it isn't cold."

"I'll come with you and help search," suggested Amy, who had been bidding her callers good-night. "I wonder if we ought to have a lantern?"

"It would be useful," spoke Betty.

"I have one of those pocket electric flash-lights," remarked Will.

"And I can get another," said Amy. "I'll be right with you, as soon as I get my coat and rubbers."

Soon the six young people were tramping through the storm, which seemed to be increasing in severity, though knowing how Mollie would worry about her little brother being out in it, the others kept insisting that it was a mere flurry, that it would amount to nothing, and would soon be over, or turn to rain.

But the snow did not itself hold out any such mild promises as that, and Mollie shivered as she felt the