“It will probably be necessary for me to see you at the Hall,” said Holmes. “I would only ask you now, sir, whether you have formed any explanation in your own mind as to the mysterious disappearance of your son?”

“No, sir, I have not.”

“Excuse me if I allude to that which is painful to you, but I have no alternative. Do you think that the Duchess had anything to do with the matter?”

The great minister showed perceptible hesitation.

“I do not think so,” he said, at last.

“The other most obvious explanation is that the child has been kidnapped for the purpose of levying ransom. You have not had any demand of the sort?”

“No, sir.”

“One more question, your Grace. I understand that you wrote to your son upon the day when this incident occurred.”