can be seen in the letter written by R. W. Emerson to Walt Whitman after reading Leaves of Grass, which Whitman self-published, but which was not at that point going anywhere. You can read about it here. Allow me just to post the actual text of the letter Emerson wrote:
Dear Sir,
I am not blind to the worth of the wonderful gift of Leaves of Grass. I find it the most extraordinary piece of wit and wisdom that America has yet contributed. I am very happy in reading it, as great power makes us happy. It meets the demand I am always making of what seemed the sterile & stingy Nature, as if too much handiwork, or too much lymph in the temperament, were making our Western wits fat and mean. I give you joy of your free and brave thought. I have great joy in it. I find incomparable things said incomparably well, as they must be. I find the courage of treatment which so delights us, & which large perception only can inspire.
I greet you at the beginning of a great career, which yet must have had a long foreground somewhere, for such a start. I rubbed my eyes a little, to see if this sunbeam were no illusion; but the solid sense of the book is a sober certainty. It has the best merits, namely, of fortifying & encouraging.
I did not know until I, last night, saw the book advertised in a newspaper, that I could trust the name real & available for a post-office. I wish to see my benefactor, & have felt much like striking my tasks, & visiting New York to pay my respects.
R.W. Emerson