But we don't know what the thing was

“But we don't know what the thing was,” said Harry, looking at the sinisterly smooth water.

“What the things are, you mean,” said Dumbledore. “I doubt very much that there is only one of them. Shall we walk on?”

“Professor?”

“Yes, Harry?”

“Do you think we're going to have to go into the lake?”

“Into it? Only if we are very unfortunate.”

“You don't think the Horcrux is at the bottom?”

“Oh no ... I think the Horcrux is in the middle.”

And Dumbledore pointed toward the misty green light in the center of the lake.

“So we're going to have to cross the lake to get to it?”

“Yes, I think so.”

Harry did not say anything. His thoughts were all of water monsters, of giant serpents, of demons, kelpies, and sprites...

“Aha,” said Dumbledore, and he stopped again; this time, Harry really did walk into him; for a moment he toppled on the edge of the dark water, and Dumbledore's

uninjured hand closed tightly around his upper arm, pulling him back. “So sorry, Harry, I should have given warning. Stand back against the wall, please; I think I

have found the place.”

Harry had no idea what Dumbledore meant; this patch of dark bank was exactly like every other bit as far as he could tell, but Dumbledore seemed to have detected

something special about it. This time he was running his hand, not over the rocky wall, but through the thin air, as though expecting to find and grip something

invisible.

“Oho,” said Dumbledore happily, seconds later. His hand had closed in midair upon something Harry could not see. Dumbledore moved closer to the water; Harry watched

nervously as the tips of Dumbledore's buckled shoes found the utmost edge of the rock rim. Keeping his hand clenched in midair, Dumbledore raised his wand with the

other and tapped his fist with the point.

Immediately a thick coppery green chain appeared out of thin air, extending from the depths of the water into Dumbledore's clenched hand. Dumbledore tapped the chain,

which began to slide through his fist like a snake, coiling itself on the ground with a clinking sound that echoed noisily off the rocky walls, pulling something from

the depths of the black water. Harry gasped as the ghostly prow of a tiny boat broke the surface, glowing as green as the chain, and floated, with barely a ripple,

toward the place on the bank where Harry and Dumbledore stood.

“How did you know that was there?” Harry asked in astonishment.

“Magic always leaves traces,” said Dumbledore, as the boat hit the bank with a gentle bump, “sometimes very distinctive traces. I taught Tom Riddle. I know his

style.”

“Is ... is this boat safe?”

“Oh yes, I think so. Voldemort needed to create a means to cross the lake without attracting the wrath of those creatures he had placed within it in case he ever

wanted to visit or remove his Horcrux.”

“So the things in the water won't do anything to us if we cross in Voldemort's boat?”

“I think we must resign ourselves to the fact that they will, at some point, realize we are not Lord Voldemort. Thus far, however, we have done well. They have allowed

us to raise the boat.”