“He wants twenty-five dollars by to-morrow night!” whispered Libbie, meeting Betty in the hall after her last visit to the buried bottle.  “Oh, Betty, what shall we do?”

Both girls had watched patiently and furtively in their spare time in an effort to detect the person who dug up the bottle, but they had never seen any one go near the spot.

As it happened, when Libbie whispered her news to Betty, they were both on their way to recitation with Miss Jessup whose current events class both girls nominally enjoyed.  To-day Betty found it impossible to fix her mind on the brisk discussions, and half in a dream heard Libbie flunk dismally.

When next she was conscious of what was going on about her—­she had been turning Libbie’s troubles over and over in her mind without result—­Miss Jessup was speaking to her class about the “association of ideas.”

“We won’t go very deeply into it this morning,” she was saying, “but you’ll find even the surface of the subject fascinating.”

Then she began a rapid fire of questions to which Betty paid small attention till the sound of Ada Nansen’s name aroused her.

“Key, Ada?” asked Miss Jessup.

The answers were supposed to indicate definite ideas.

“Key hole,” said Ada promptly.

“Purse?”

“Money.”

“Bee?” asked Miss Jessup.

To her surprise and that of the listening class, nine-tenths of whom were forming the word “honey” with their lips, Ada answered without hesitation, “Bottle.”

“You must have thought I meant the letter ‘B,’” said the teacher lightly, passing on to the next pupil.

Betty heard the dismissal bell with real relief.  She cornered Libbie in the hall as the class streamed out and announced a decision.

“I’ll have to go see Bob—­I’ll paddle one of the canoes,” she said hurriedly.

“If any one asks for me, say I’m out on the lake.”

Betty was now an expert with the paddle, and the trip across the lake was easy of accomplishment.  She had the great good fortune to meet Bob returning from a recitation, and though surprised to see her, he knew she must have come by boat or canoe.  The boys had gone the next day and brought back the canoes from the woods where they had placed them during the storm.

“I’m ever so sorry, Bob,” said Betty earnestly, “But—­could you lend me twenty-five dollars?”

Bob whistled.

“I could,” he admitted cautiously.  “What’s it for, Betsey?”

“That,” said Betty, “is a secret.”

Bob glanced at her sharply.  His chin hardened.

“Come down here where we won’t be interrupted,” he said, leading the way to the wharf.  “You’ll have to give me a good reason for wanting the money, Betty.”

CHAPTER XIX

BOB’S SOLUTION

“If you wanted twenty-five dollars and I had it,” said Betty persuasively, “I’d give it to you without asking a solitary question.”