"What for?" he asked.
"To look after his island while he is away. Mr. Davidson has gone to Denver. And Mr. Kellogg is going to try to put an end to all these burglaries. So there's a warning for you."
He pondered the warning and wrinkled his forehead.
"Customs officers still hanging around?" he asked.
"I am told they are."
"And that Canadian spy-chaser—is he still on the job?"
"I saw the launch again yesterday."
"Is Davidson's police patrol cruising, too?"
"Of course. And they've put on another boat."
Rosalind noted with satisfaction that he was showing traces of worriment.