What feelings does the narrator have when he looks at the House of Usher?

From the text:

"... I but mention it to show the vivid force of the sensations which oppressed me. I had so worked upon my imagination as really to believe that about the whole mansion and domain there hung an atmosphere peculiar to themselves and their immediate vicinity—an atmosphere which had no affinity with the air of heaven, but which had reeked up from the decayed trees, and the gray wall, and the silent tarn—a pestilent and mystic vapor, dull, sluggish, faintly discernible, and leaden-hued."

As the Narrator surveys the house. He notes how old it appears. He sees that individual stones seem on the verge of crumbling while the edifice as a whole appears remarkably stable (despite the fissure).