Because you have to search.
The epigraph says to search outside. What do you think it means by outside? And no, you don't need to physically exit the room.
Margins. You search in the margins.
Indents are not in the margins. The letters along edges of the paragraph are not in the margins. The page is full justification, so you can tell what's in the margins and what isn't by using a straight edge.
Find as many things as you can. And then remember the symbol.
It's a page on its side. It indicates how to look at the page.
Google an event that happened in 1838.