the Braes of Kirtle,
Was lovely as a Grecian maid
Adorned with wreaths of myrtle.

Why adorned with wreaths of myrtle? Wordsworth himself tells us. His
subject had already been treated in Scotch poems "in simple ballad
strain," so, he says, "at the outset I threw out a classical image to
prepare the reader for the style in which I meant to treat the story,
and so to preclude all comparison." No one, whose object was just to
tell the story, would compare Ellen with a Grecian maid and her wreaths
of myrtle; but Wordsworth must do so to show us how he means to tell it,
and, as he forgets to mention, so that he may rhyme with Kirtle. That is
all professionalism, all a device for making expression easy, practised
by a great poet because at the moment he had nothing to express. But art
is always difficult and cannot be made easy by this means. We need not
take a malicious pleasure in such lapses of the great poet; but it is
well to know when Homer nods, even though he uses all his craft to
pretend that he is wide awake. Criticism may have a negative as well as
a positive value. It may set us on our guard against professionalism
even in the greatest artists, and most of all in them. For it is they
who begin professionalism and, with the mere momentum of their vitality,
make it attractive. Because they are great men and really accomplished,
they can say nothing with a grand air; and these grand nothings of
theirs allure us just because they are nothings and make no demands
upon our intelligence. That is art indeed, we cry: and we intoxicate
ourselves with it because it is merely art. "The quality of mercy is not
strained" is far more popular than Lear's speech, "No, no, no! Come,
let's away to prison," because it is professional rhetoric; it is what
Shakespeare could write at any moment, whereas the speech of Lear is
what Lear said at one particular moment. The contrast between the two is
the contrast well put in the epigram about Barry and Garrick in their
renderings of King Lear:--

A king, aye, every inch a king, such Barry doth appear.
But Garrick's quite another thing; he's every inch King Lear.

We admire the great artist when he is every inch a king more than when
he has lost his kingship in his passion.

He no doubt knows the difference well enough. But he wishes to do
everything well, he has a natural human delight in his own
accomplishment; and a job to finish. Shak