The complete essay can be found at the website of The Edgar Allan Poe Society
The part of this essay I find most interesting occurs about half way through the text:
I would define, in brief, the Poetry of words as The Rhythmical Creation of Beauty. Its sole arbiter is Taste. With the Intellect or with the Conscience, it has only collateral relations. Unless incidentally, it has no concern whatever either with Duty or with Truth.
A few words, however, in explanation. That pleasure which is at once the most pure, the most elevating, and the most intense, is derived, I maintain, from the contemplation of the Beautiful. In the contemplation of Beauty we alone find it possible to attain that pleasurable elevation, or excitement, of the soul, which we recognise as the Poetic Sentiment, and which is so easily distinguished from Truth, which is the satisfaction of the Reason, or from Passion, which is the excitement of the heart. I make Beauty, therefore — using the word as inclusive of the sublime — I make Beauty the province of the poem, simply because it is an obvious rule of Art that effects should be made to spring as directly as possible from their causes: — no one as yet having been weak enough to deny that the peculiar elevation in question is at least most readily attainable in the poem. It by no means follows, however, that the incitements of Passion, or the precepts of Duty, or even the lessons of Truth, may not be introduced into a poem, and with advantage; for they may subserve, incidentally, in various ways, the general purposes of the work: — but the true artist will always contrive to tone them down in proper subjection to that Beauty which is the atmosphere and the real essence of the poem.
That's a long quotation, but I think it's highly relevant to the poetic work of CAS. Many a poem from the Bard of Auburn features Beauty as a theme; one example which I recently read is "Beauty Implacable":
It seems natural for a poet to be focused on Beauty as a theme and subject, for as Poe notes in his essay,
In the contemplation of Beauty we alone find it possible to attain that pleasurable elevation, or excitement, of the soul, which we recognise as the Poetic Sentiment...Beauty which is the atmosphere and the real essence of the poem.
From Poe's manifesto I sense the origins of CAS' own creative agenda. While I don't know for sure that CAS read this particular essay, I strongly suspect that he did, since he was a great admirer of Poe, and this particular essay is a well-known item from Poe's oeuvre.
That these two artists had similar inclinations is no surprise, but I appreciate Poe's thoughtful argument both because I agree with it, and because it sheds some light on CAS' own convictions as a creator.