What are five clues in The Hound of the Baskervilles and what does each one mean?

In Sir Arthur Conan Doyle's novel, many of the clues Holmes and Watson discover are red herrings, which lead down a false trail, while others are true clues to solving the mystery. Here are some of each:

Red Herrings

1. The legend of the curse of the Baskervilles: this story forms the basis for the way Sir Charles was killed, but the murderer is using it to help hide his crime by making people think it was a supernatural event.

2. Mrs. Barrymore crying: this may cast some suspicion on the Barrymores, especially since Mr. Barrymore was the last person to see Sir Charles alive, but her tears have to do with her escaped convict brother.

3. Mr. Barrymore flashing a candle in the window: again, it makes him look suspicious, but it has to do with Selden, the convict.

4. The Man on the Tor: Watson observes a mysterious figure out in the wild area around Baskerville Hall; it turns out to be Holmes himself, who has been gathering information while wanting to keep away from the Hall.

5. Mr. Frankland: the disagreeable neighbor seems as if he could have been involved in the crime, but he has no direct involvement.

Actual Clues

1. The boots: because the new boot was returned after it was stolen from the hotel and then an old boot was stolen, Holmes realizes they are indeed dealing with a real dog, not a phantom (which he rejected anyway).

2. The convict attacked: when the convict, who was wearing some of Sir Charles' old clothes given to him by the Barrymores, is attacked by the dog, it shows that the dog had earlier been put onto Sir Charles' scent.

3. Mr. Stapleton's odd reaction to Sir Henry: when Sir Henry displays romantic interest toward Mr. Stapleton's "sister," it suggests their relationship is not as it appears. It turns out they are married.

4. Miss Stapleton's reaction to Watson: when Miss Stapleton first meets Watson, she thinks he is Sir Henry, and she warns him of danger. That shows she knows more than one would think.

5. The LL letter: the letter signed "LL" that Watson gets from Barrymore is key to the death of Sir Charles; Holmes is able to find Laura Lyons and make the connection between her and Mr. Stapleton.

6. The portrait: Holmes notices that Stapleton bears a remarkable likeness to the portrait of the Baskerville ancestor, helping him link Stapleton as a relative, making the motive obvious. If Sir Henry dies, Stapleton (under his real name) would become the heir.

7. The warning note: although they don't actually find out who sent it in time to help them, the note was written by Mrs. Stapleton because she was not in favor of her husband's plans. She also tried to warn Sir Henry, but she spoke with Watson instead.

As in any good mystery, sifting out the red herrings from the real clues creates a challenge for the detective—as well as for the reader.