>With preposotions, as has the general sense of as far as, so far as, and thus restricts or specially denies the reference of the preposition;
e.g)as against, as between, as anent, as concerning, as for, as to, as touching, have all the sense of 'as it regerds, so far as it concerns, with respect or reference to.' In as in, as by, as after, and other obsolete combinations, as was almost pleonastic.
severally:each in turn, individually
as far as とeven if は文法的に同じ構造を持っているっぽい。