Source identified1
“But nature is a stranger yet; The ones that cite her most Have never passed her haunted house, Nor simplified her ghost.”
Even close observers do not fully explain nature in this ending; familiarity with natural objects leaves room for strangeness, uncertainty and intellectual humility.
Source note: “A Well,” Poems: Third Series (1896), Project Gutenberg #12242. The ghost and haunted-house language is metaphorical, emphasizing nature's unresolved mystery.