During the whole of a dull, dark, and soundless day in the autumn of the year, 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 evening drew on, within view of the melancholy house of usher. i know not how it was—but, with the first glimpse of the building, a sense of insufferable gloom pervaded my spirit . . in this excerpt from edgar allan poe's "the fall of the house of usher," what mood do these lines evoke in the reader