“It’s a code,” said Grant, ignoring George’s facetious remark.

“We know that,” agreed Fred. “Don’t be so mysterious.”

“What’s the highest number in it?” demanded Grant.

“He sounds like a trick man,” laughed George jeeringly.

“No treasure for Pop,” said Grant shortly. “What’s the highest number in it?”

“I guess we’ll have to do it this way,” said John with a sigh. “Let me see,” he added. “I guess twenty-five is the highest number.”

“All right. How many letters are there in the alphabet?”

“Twenty-six.”

“But, Grant,” Fred protested, “I don’t see what you’re getting at?”

“You will soon enough. Just have a little patience.”