Dumbledore approached the basin and Harry followed. Side by side, they looked down into it. The basin was full of an emerald liquid emitting that phosphorescent glow.
“What is it?” asked Harry quietly.
“I am not sure,” said Dumbledore. “Something more worrisome than blood and bodies, however.”
Dumbledore pushed back the sleeve of his robe over his blackened hand, and stretched out the tips of his burned fingers toward the surface of the potion.
“Sir, no, don’t touch—!”
“I cannot touch,” said Dumbledore, smiling faintly. “See? I cannot approach any nearer than this. You try.”
Staring, Harry put his hand into the basin and attempted to touch the potion. He met an invisible barrier that prevented him coming within an inch of it. No matter how hard he pushed, his fingers encountered nothing but what seemed to be solid and flexible air.
“Out of the way, please, Harry,” said Dumbledore.
He raised his wand and made complicated movements over the surface of the potion, murmuring soundlessly. Nothing happened, except perhaps that the potion glowed a little brighter. Harry remained silent while Dumbledore worked, but after a while Dumbledore withdrew his wand, and Harry felt it was safe to talk again.
“You think the Horcrux is in there, sir?”
“Oh yes.” Dumbledore peered more closely into the basin. Harry saw his face reflected, upside down, in the smooth surface of the green potion. “But how to reach it? This potion cannot be penetrated by hand, Vanished, parted, scooped up, or siphoned away, nor can it be Transfigured, Charmed, or otherwise made to change its nature.”
Almost absentmindedly, Dumbledore raised his wand again, twirled it once in midair, and then caught the crystal goblet that he had conjured out of nowhere.
“I can only conclude that this potion is supposed to be drunk.”
“What?” said Harry. “No!”
“Yes, I think so: Only by drinking it can I empty the basin and see what lies in its depths.”
“But what if—what if it kills you?”
“Oh, I doubt that it would work like that,” said Dumbledore easily. “Lord Voldemort would not want to kill the person who reached this island.”
Harry couldn’t believe it. Was this more of Dumbledore’s insane determination to see good in everyone?
“Sir,” said Harry, trying to keep his voice reasonable, “sir, this is Voldemort we’re—”
“I’m sorry, Harry; I should have said, he would not want to immediately kill the person who reached this island,” Dumbledore corrected himself. “He would want to keep them alive long enough to find out how they managed to penetrate so far through his defenses and, most importantly of all, why they were so intent upon emptying the basin. Do not forget that Lord Voldemort believes that he alone knows about his Horcruxes.”