Mr. Phelps has them all take out their textbooks and begin reading the section on the distinctions between hexes, jinxes, curses, and lesser known categories of baleful spell. He wanders up and down the rows with his arms folded and his wand in his hand, peeping past his elbow, making sure everyone is reading.

Stroll.

Stroll.

He is also making preparations for a certain demonstration.

He passes in front of Sherlock.