"How do you know it was from the father?"

"The coat of arms was on the envelope, and it was addressed in the
Duke's peculiar stiff hand. Besides, the Duke remembers having written."

"When had he a letter before that?"

"Not for several days."

"Had he ever one from France?"

"No; never.

"You see the point of my questions, of course. Either the boy was
carried off by force or he went of his own free will. In the latter case
you would expect that some prompting from outside would be needed to
make so young a lad do such a thing. If he has had no visitors, that
prompting must have come in letters. Hence I try to find out who were
his correspondents."

"I fear I cannot help you much. His only correspondent, so far as I
know, was his own father."

"Who wrote to him on the very day of his disappearance. Were the
relations between father and son very friendly?"

"His Grace is never very friendly with anyone. He is completely immersed
in large public questions, and is rather inaccessible to all ordinary
emotions. But he was always kind to the boy in his own way."

"But the sympathies of the latter were with the mother?"

"Yes."

"Did he say so?"

"No."

"The Duke, then?"

"Good heavens, no!"

"Then how could you know?"

"I have had some confidential talks with Mr. James Wilder, his Grace's
secretary. It was he who gave me the information about Lord Saltire's
feelings."

"I see. By the way, that last letter of the Duke's--was it found in the
boy's room after he was gone?"

"No; he had taken it with him. I think, Mr. Holmes, it is time that we
were leaving for Euston."

"I will order a four-wheeler. In a quarter of an hour we shall be at
your service. If you are telegraphing home, Mr. Huxtable, it would
be well to allow the people in your neighbourhood to imagine that
the inquiry is still going on in Liverpool, or wherever else that red
herring led your pack. In the meantime I will do a little quiet work at
your own doors, and perhaps the scent is not so cold but that two old
hounds like Watson and myself may get a sniff of it."

That evening found us in the cold, bracing atmosphere of the Peak
country, in which Dr. Huxtable's famous school is situated. It was
already dark when we reached it. A card was lying on the hall table,
and the butler whispered something to his master, who turned to us with
agitation in every heavy feature.

"The Duke is here," said he. "The Duke and Mr. Wilder are i