Read "The Voice of Silence" at The Eldritch Dark:
This poem has an interesting pedigree, since it was among a batch of poems that the young Clark Ashton Smith (CAS) sent to George Sterling, an older poet who would come to serve as his mentor for many years.
Correspondence between CAS and George Sterling has been collected in a volume from Hippocampus Press, and one of the letters from Sterling to CAS includes some notes on this poem. Sterling comments on the very last line of "The Voice of Silence" (I include the preceding line for context):
Some few words from the Perfect Poem float
To us. Ah, would that we the whole might learn!
The suggestion from Sterling is that CAS should "avoid lines made up entirely of monosyllables", advice that Sterling apparently derived from his own mentor Ambrose Bierce.
Sterling's suggestion does seem rather misplaced to me, since one of the strengths of this poem is the use of a less exotic vocabulary than CAS is often wont to use, which gives a smooth flow to the reading experience. It seems to me that those last two lines are really quite powerful, yearning for the experience of the "Perfect Poem", and lamenting our inability to have that experience.
The good news is that CAS apparently ignored Sterling's advice. A fine testament to the younger poet's confidence in his own art.