The new clues

More than a month has passed, and no one has won the $20 Destinations Booksellers gift card yet.

Therefore, first of all, Destinations owners Randy and Ann Smith have posted an announcement of the contest on Destinations' own blog ; and second, I am posting two new clues.

Once again, the question is:

What is the literary significance of the complex number (-7/2) + (i(sqrt(445/3))/2)?

This number is alluded to in a work by a major literary figure. The winning solution must: (1) indicate the author; (2) give the opening line of the work; and (3) show how the number is derived from the text of the work. (It is not written out explicitly, but is derivable from the text in a straightforward way.)

For nonmathematicians, a "complex number" is the sum of a "real number," a more or less ordinary number like 0 or 32 or the square root of 2, and an "imaginary number," which is a multiple of the square root of -1, denoted by the symbol i. The abbreviation sqrt stands for "square root."

I have given the following six clues:

(1) The work is in English.
(2) The work appears in the standard editions of the author's complete works.
(3) The author is primarily known as an author (rather than, say, a scientist).
(4) The work is not a work of science fiction.
(5) The work was written and published between 1850 and 1900.
(6) The work is an untitled poem.

Now for the seventh and eighth clues:

(7) The author is British.
(8) The principal subject of the poem is not mathematics.

I am also clarifying the fifth clue:

(5') While most of the author's works have known dates, the poem in question is one of the few whose date is unknown (though certainly between 1850 and 1900), at least according to the editions I have consulted.

Good luck and happy solving! Please post your solution, or any queries, as a comment to this post.