"Do you know him? He's a stranger to me."

"It's Mr. Parker," said Betty.

John drew in his breath sharply.

"Are you sure?"

"Positive."

John laughed quietly. He thought for a moment, then beckoned to the hovering waiter.

"What are you going to do?" asked Betty.

"Bring me a small lemon," said John.

"Lemon squash, sir?"

"Not a lemon squash. A plain lemon. The fruit of that name. The common or garden citron, which is sharp to the taste and not pleasant to have handed to one. Also a piece of note paper, a little tissue paper, and an envelope.