Slughorn looked deeply troubled now

Slughorn looked deeply troubled now: he was gazing at Riddle as though he had never seen him plainly before, and Harry could tell that he was regretting entering into

the conversation at all.

“Of course,” he muttered, “this is all hypothetical, what we're discussing, isn't it? All academic...”

“Yes, sir, of course,” said Riddle quickly.

“But all the same, Tom... keep it quiet, what I've told—that's to say, what we've discussed. People wouldn't like to think we've been chatting about Horcruxes. It's a

banned subject at Hogwarts, you know... Dumbledore's particularly fierce about it...”

“I won't say a word, sir,” said Riddle, and he left, but not before Harry had glimpsed his face, which was full of that same wild happiness it had worn when he had

first found out that he was a wizard, the sort of happiness that did not enhance his handsome features, but made them, somehow, less human...

“Thank you, Harry,” said Dumbledore quietly. “Let us go...”

When Harry landed back on the office floor Dumbledore was already sitting down behind his desk. Harry sat too and waited for Dumbledore to speak.

“I have been hoping for this piece of evidence for a very long time,” said Dumbledore at last. “It confirms the theory on which I have been working, it tells me that

I am right, and also how very far there is still to go...”

Harry suddenly noticed that every single one of the old headmasters and headmistresses in the portraits around the walls was awake and listening in on their

conversation. A corpulent, red nosed wizard had actually taken out an ear trumpet.

“Well, Harry,” said Dumbledore, “I am sure you understood the significance of what we just heard. At the same age as you are now, give or take a few months, Tom

Riddle was doing all he could to find out how to make himself immortal.”

“You think he succeeded then, sir?” asked Harry. “He made a Horcrux? And that's why he didn't die when he attacked me? He had a Horcrux hidden somewhere? A bit of

his soul was safe?”

“A bit... or more,” said Dumbledore. “You heard Voldemort, what he particularly wanted from Horace was an opinion on what would happen to the wizard who created more

than one Horcrux, what would happen to the wizard so determined to evade death that he would be prepared to murder many times, rip his soul repeatedly, so as to store

it in many, separately concealed Horcruxes. No book would have given him that information. As far as I know—as far, I am sure, as Voldemort knew—no wizard had ever

done more than tear his soul in two.”

Dumbledore paused for a moment, marshaling his thought, and then said, “Four years ago, I received what I considered certain proof that Voldemort had split his soul.”

“Where?” asked Harry. “How?”

“You handed it to me, Harry,” said Dumbledore. “The diary, Riddle's diary, the one giving instructions on how to reopen the Chamber of Secrets.”

“I don't understand, sir,” said Harry.