| Quote #1
Although, as boys, we had been even intimate associates, yet I really knew little of my friend. His reserve had been always excessive and habitual. (3)
And even as the narrator gets to know Roderick again, there remains a barrier between them. Roderick remains excessively reserved.
| Quote #2
I had learned, too, the very remarkable fact, that the stem of the Usher race, all time-honoured as it was, had put forth, at no period, any enduring branch; in other words, that the entire family lay in the direct line of descent, and had always, with very trifling and very temporary variation, so lain. (3)
The Usher family was as self-isolating and insular as Madeline and Roderick seem to be. Insular means lacking contact with other people.
| Quote #3
The windows were long, narrow, and pointed, and at so vast a distance from the black oaken floor as to be altogether inaccessible from within. (7)
There is a definite sense of confinement here; the windows are out of reach, to escape is impossible.