Choose Your Own Chemical Adventure

"Do come in", she says. "My name is Mrs Johns. What did you say yours was?" You tell her your name. "He's not here at the moment, but he'll arrive shortly. He's always very punctual. I'm sure he won't object to you waiting in his study."

She ushers you upstairs to a room on the first floor, with a window overlooking the street. Entering the room, your eyes are drawn to the many shelves full of books and to a Buro in the corner.

What do you do?