It was this letter, if you can call it a letter, which reached me this morning." He laid an envelope upon the table, and we all bent over it.

It was of common quality, grayish in colour.

The address, "Sir Henry Baskerville, Northumberland Hotel," was printed in rough characters; the postmark "Charing Cross," and the date of posting the preceding evening.
"Who knew that you were going to the Northumberland Hotel ?" asked Holmes, glancing keenly across at our visitor.
"No one could have known.

We only decided after I met Dr.
Mortimer." "But Dr.Mortimer was no doubt already stopping there ?" "No, I had been staying with a friend," said the doctor.

"There was no possible indication that we intended to go to this hotel." "Hum! Someone seems to be very deeply interested in your movements." Out of the envelope he took a half-sheet of foolscap paper folded into four.