Regulus made a face. But he took a cue from Lily and dragged open his own bag, pulling out a tome of arithmancy, a scroll and a quill. And in painfully precise penmaniship, started working on equations and charts. This was really the subject he shined in. All the exact numbers just made sense even when variables were hard to solve.

After completing one chart, he looked over at that cauldron that was, in his opinion, doing nothing.

"Has it been a half an hour yet?" It had not been a half an hour yet.