Bella is confused because she is not sure whether they sell Polaroid instant cameras at the dusty magic shop. She believes Maestro Daguerre has brought it in with him. He has been at the store for hours and has not bought one thing.
The main idea of the passage above from Cotton Mather's "The Wonders of the Invisible World" is to justify the outcome of the trials. Thank you for posting your question. I hope this answer helped you. Let me know if you need more help.
