Read "Trope" at The Eldritch Dark:
There is a significant typo in the version of this poem at The Eldritch Dark; in the second line of the second stanza "loin" is clearly out of place, and the correct reading is:
For when the lake at even
Is lorn of wind and air,
The moon lies perfect there
As in another heaven.
This poem, and that second stanza in particular, strikes me as a less-accomplished take on the same subject presented in "Simile", which I read yesterday. Compare the stanza above to the description of a similar image in "Simile":
...as a lake,
Lulled in to sombre crystal by sad pines
Doth hold the moon made perfect in its heart
The latter is much richer with poetic expression, and demonstrates the considerable powers of language that Clark Ashton Smith could command when he chose to.