The hound of Baskerville chapter 5

Holmes claimed he knew the guests and went onto describe them, which led the porter into correcting him with the accurate information.

The book showed that two names had been added after that of Baskerville. One was Theophilus Johnson and family, of Newcastle; the other Mrs. Oldmore and maid, of High Lodge, Alton.
"Surely that must be the same Johnson whom I used to know," said Holmes to the porter. "A lawyer, is he not, grayheaded, and walks with a limp?"
"No, sir, this is Mr. Johnson, the coal-owner, a very active gentleman, not older than yourself."
"Surely you are mistaken about his trade?"
"No, sir! he has used this hotel for many years, and he is very well known to us."
"Ah, that settles it. Mrs. Oldmore, too; I seem to remember the name. Excuse my curiosity, but often in calling upon one friend one finds another."
"She is an invalid lady, sir. Her husband was once mayor of Gloucester. She always comes to us when she is in town."
"Thank you; I am afraid I cannot claim her acquaintance. We have established a most important fact by these questions, Watson," he continued in a low voice as we went upstairs together. "We know now that the people who are so interested in our friend have not settled down in his own hotel. That means that while they are, as we have seen, very anxious to watch him, they are equally anxious that he should not see them. Now, this is a most suggestive fact."