I know how disagreeable it is to make use of hard words before a Lady;
but't is so much the concern of a Poet to have his works understood, and
particularly by your Sex, that you must give me leave to explain two or
three difficult terms.

The Rosicrucians are a people I must bring you acquainted with. The best
account I know of them is in a French book call'd 'Le Comte de
Gabalis', which both in its title and size is so like a Novel, that
many of the Fair Sex have read it for one by mistake. According to these
Gentlemen, the four Elements are inhabited by Spirits, which they call
Sylphs, Gnomes, Nymphs, and Salamanders. The Gnomes or Daemons of Earth
delight in mischief; but the Sylphs whose habitation is in the Air, are
the best-condition'd creatures imaginable. For they say, any mortals may
enjoy the most intimate familiarities with these gentle Spirits, upon a
condition very easy to all true Adepts, an inviolate preservation of
Chastity.

As to the following Canto's, all the passages of them are as fabulous,
as the Vision at the beginning, or the Transformation at the end;
(except the loss of your Hair, which I always mention with reverence).
The Human persons are as fictitious as the airy ones; and the character
of Belinda, as it is now manag'd, resembles you in nothing but in
Beauty.

If this Poem had as many Graces as there are in your Person, or in your
Mind, yet I could never hope it should pass thro' the world half so
Uncensur'd as You have done. But let its fortune be what it will, mine
is happy enough, to have given me this occasion of assuring you that I
am, with the truest esteem, Madam,