"Mr. Blind, tell me: why can stirring counterclockwise and adding a little Moonstone powder eliminate a smell you can't even detect?"
"B-because... stirring can... make the smell disperse faster?"
"Five points from Gryffindor. If too much Sneezewort Tincture is used, the potion as a whole becomes unstable. That is what causes the foul odor."
"Adding Moonstone powder and stirring counterclockwise can stabilize the potion. Mr. Blind, is there room in that head of yours for anything besides dueling?"
"Mr. Blind, do you need to touch and chew these potion ingredients? After all, you can neither smell their scent nor see their color. Perhaps only touch and taste can help you identify potion ingredients."
"I don't think that'll be necessary... Professor Snape... I can tell... this is Potentilla Root."
"Surprising. It seems that faulty Calming Potion worked remarkably well—it actually restored your sight and sense of smell. Then tell me, what will happen if Potentilla Root is added now?"
"Er... it'll... it'll change color?"
"Of course it will change color! Another five points from Gryffindor! I asked what color it would become! Can't you see? Purple! A color that represents utter failure! Now tell me why!"
"Because... because... because the timing was wrong?"
"Of course the timing was wrong! Five points from Gryffindor! A Calming Potion and a Calming Draught are very similar—both require stability. Throwing in Potentilla Root so rashly will naturally cause this problem!"
Hermione bit her lip tightly, pain and pity mingling across her face. Clearly, she deeply sympathized with Ron's ordeal.
Yet her hands moved with astonishing steadiness, her quill racing across the parchment as she recorded every detail from the blackboard.
As the students finished their potions, Snape's questioning drew to a close.
He pointed at the Moondew Flower on the lectern. "Tell