I was, perhaps, the more forcibly impressed with i

I was, perhaps, the more forcibly impressed with it, as he gave it, because, in the under or mystic current of its meaning, I fancied that I perceived, and for the first time, a full consciousness on the part of Usher, of the tottering of his lofty reason upon her throne.

一つ目に、‘in the under or mystic current of its meaning’の構造がはっきりとつかめません。orは何と何を並べているのか、underはなんなのか

二つ目に、‘and for the first time’の中でなぜandがあるのでしょうかperceivedとその目的語の間にある副詞句のようにみえますがそれなら何とandで並列させているのかわかりません

No.1 回答者： PerlLearner1 回答日時： 2017/12/17 12:03

in the under current of its meaning・その意味の過小な流れ　もしくは

in the mystic current of its meaning・その意味の神秘的な流れで　となります。

because　~ and for the first timeとまだBecause にかかっています。