There are quite a few typos in the version of this poem at The Eldritch Dark, but most of them should be fairly obvious when encountered in context. The exception is the fourth stanza, which is missing an entire line (in addition to some typos), so here is the corrected text:
Exhume the withered wing-shards of ideals
Brittle and light as perished moths, or bring
To sight the mummied bats of blear mischance,
By dismal eves and moons disastrous flying,
But fallen now, and dead as are the heavens
Their vans have darkened. On beloved deaths
I muse, and through my twice-wept tears re-gather
The threads that Clotho and Lachesis have spun
And Atropos has cut; and see the bleak
Sinister gleaming of the steely shears
Behind the riven arrasses of time....
This poem from Clark Ashton Smith (CAS) directly addresses Charles Baudelaire, the author of Les Fleurs du mal and one of CAS' literary heroes. The poem leaves no doubt of the profound sympathy that CAS felt for Baudelaire's verse, with its ready acknowledgment and embrace of life's darker aspects:
Black-flickering, cloven tongues! Though we distill
Quintessences of hemlock or nepenthe,
We cannot slay the small, the subtle serpents.
Whose mother is the lamia Melancholy
That feeds upon our breath and sucks our veins,
Stifling us with her velvet volumes.
Despite the hint of resignation in the lines quoted above, and despite the overall somber tone of "Soliloquy in an Ebon Tower", it is clearly a work of affirmation, stating with confidence that the two poets (CAS and Baudelaire) have earned their right to inhabit the metaphorical tower:
Daedalus-like, a labyrinth of words
Wherein our thoughts are twi-shaped Minotaurs
The ages shall not slay.
This poem is unusually rich with learned diction and the ready invocation of legendary names from myth and fable. While those elements are found throughout CAS' body of work, this poem particularly is difficult to read without ready access to a dictionary and other reference sources. But that extra effort is well rewarded, and allows the reader to really experience the glory of what is surely one of CAS' defining statements as an artist and a poet.