Dumbledore raised his hand and gave a gentle wave. Zhang Xiao's chair immediately slid over, and the smoke screen expanded with it.
"A special variant of the Sneakoscope. Quite rare, but I believe you already know of my friend Nicolas Flamel, a reasonably competent alchemist."
He tapped the oddly shaped, potbellied silver bottle.
Go on, keep humblebragging! Nicolas Flamel, a reasonably competent alchemist, huh?
Then what did that make other alchemists? Apprentices?
Zhang Xiao watched the smoke screen without any change in his expression, as though watching a silent film.
"Professor, can we only see the images? What about sound?"
Dumbledore said slowly,
"Zhang, let me teach you a little trick. If you truly wish to observe someone, I suggest watching what they do rather than listening to what they say.
"Sound would undoubtedly divert some of our attention toward their conversation. But if we watch like this,
"you will find that many small, easily overlooked movements become wonderfully clear."
Lesson learned. With a practical trick like that, I refuse to believe you haven't spent decades secretly watching people.
Being humble and eager to learn was a traditional Chinese virtue. Zhang Xiao immediately took the advice, imitating Dumbledore as he stared intently at the smoke screen.
In the smoke, the four young wizards seemed to be having a heated argument. Malfoy's forehead was almost pressed against Harry's.
Ron and Hermione stood to one side, looking rather at a loss.
Zhang Xiao suddenly noticed a problem. Dumbledore's method did work. With all his attention on their movements, he had indeed spotted quite a few interesting little gestures.
For instance, Malfoy unconsciously rose onto the toes of one foot when he got worked up, while Hermione bit her lip.
But he lacked one crucial thing: the ability to interpret those little gestures.