“Cleverer men than you have been taken in, Portlethorpe,” remarked Mr. Lindsey.  “And the matters you speak of might have been stolen.  But let Mrs. Ralston give us her reasons for suspecting this man—­she has some strong ones, I’ll be bound.”

Mr. Portlethorpe showed signs of irritation, but Mrs. Ralston promptly took up Mr. Lindsey’s challenge.

“Sufficiently strong to have made me very uneasy of late, at any rate,” she answered.  She turned to Mr. Portlethorpe.  “You remember,” she went on, “that my first meeting with this man, when he came to claim the title and estates, was at your office in Newcastle, a few days after he first presented himself to you.  He said then that he had not yet been down to Hathercleugh; but I have since found out that he had—­or, rather, that he had been in the neighbourhood, incognito.  That’s a suspicious circumstance, Mr. Portlethorpe.”

“Excuse me, ma’am—­I don’t see it,” retorted Mr. Portlethorpe.  “I don’t see it at all.”

“I do, then!” said Mrs. Ralston.  “Suspicious, because I, his sister, and only living relation, was close by.  Why didn’t he come straight to me?  He was here—­he took a quiet look around before he let any one know who he was.  That’s one thing I have against him—­whatever you say, it was very suspicious conduct; and he lied about it, in saying he had not been here, when he certainly had been here!  But that’s far from all.  The real Gilbert Carstairs, Mr. Lindsey, as Mr. Portlethorpe knows, lived at Hathercleugh House until he was twenty-two years old.  He was always at Hathercleugh, except when he was at Edinburgh University studying medicine.  He knew the whole of the district thoroughly.  But, as I have found out for myself, this man does not know the district!  I have discovered, on visiting him—­though I have not gone there much, as I don’t like either him or his wife—­that this is a strange country to him.  He knows next to nothing—­though he has done his best to learn—­of its features, its history, its people.  Is it likely that a man who had lived on the Border until he was two-and-twenty could forget all about it, simply because he was away from it for thirty years?  Although I was only seven or eight when my brother Gilbert left home, I was then a very sharp child, and I remember that he knew every mile of the country round Hathercleugh.  But—­this man doesn’t.”

Mr. Portlethorpe muttered something about it being very possible for a man to forget a tremendous lot in thirty years, but Mrs. Ralston and Mr. Lindsey shook their heads at his dissent from their opinion.  As for me, I was thinking of the undoubted fact that the supposed Sir Gilbert Carstairs had been obliged in my presence to use a map in order to find his exact whereabouts when he was, literally, within two miles of his own house.