"during the whole of a dull, dark, and soundless day in the autumn of the , when the clouds hung oppressively low in the heavens, I had been passing alone, on horseback, through a singularly dreary tract of country; and at length found myself, as the shades of the evening drew on, within view of the melancholy House of Usher" (Poe 13).The depressing, dreary mood is shown through poe's word choice and extremely descriptive language.
"A small picture presented the interior of an immensely long and rectangular vault or tunnel, with low walls, smooth, white, and without interruption or device. Certain accessory points of the design served well to convey the idea that this excavation lay at an exceeding depth below the surface of the earth. No outlet was observed in any portion of its vast extent, and no torch, or other artificial source of light was discernible; yet a flood of intense rays rolled throughout, and bathed the whole in a ghastly and inappropriate splendour."(Poe 20) Rodrick usher painting the vault in an attempt to help him recover is ironic because putting his sister in the real tomb will ultimately lead to his death.
"At the request of Usher, I personally aided him in the arrangements for the temporary entombment. The body having been encoffined, we two alone bore it to its rest. The vault in which we placed it (and which had been so long unopened that our torches, half smothered in its oppressive atmosphere, gave us little opportunity for investigation) was small, damp, and entirely without means of admission for light"(Poe 23-24) Usher and the narrator have put Madeline into the tomb, and as Roderick's mental health worsened the mood begins to become suspenseful.
"Not hear it? -- yes, I hear it, and have heard it. Long -- long -- long -- many minutes, many hours, many days, have I heard it -- yet I dared not -- oh, pity me, miserable wretch that I am! -- I dared not -- I dared not speak! We have put her living in the tomb! Said I not that my senses were acute? I now tell you that I heard her first feeble movements in the hollow coffin. I heard them -- many, many days ago -- yet I dared not -- I dared not speak! (poe 29) The narrator discovers that madeline has been buried alive and this revelation changes the mood from suspenseful to horrifying ad the impending threat of madeline's wrath draws nearer.
"While I gazed, this fissure rapidly widened -- there came a fierce breath of the whirlwind -- the entire orb of the satellite burst at once upon my sight -- my brain reeled as I saw the mighty walls rushing asunder -- there was a long tumultuous shouting sound like the voice of a thousand waters -- and the deep and dank tarn at my feet closed sullenly and silently over the fragments of the "House of Usher."' The readers now discover the double meaning behind the phrase "fall of the house of usher", meaning the end of the family line, and the literal collapse of the house.