He had directed, in great part, the movable embellishments of the seven chambers, upon occasion of this great fête; and it was his own guiding...

As for figurative language, Poe makes an allusion to the Victor Hugo play, Hernani, first performed in 1830, in order to enrich his own imagery by relying on the splendor associated with another famous production.  Poe also personifies the clock, giving it a voice, and thus making it seem more powerful and symbolic than we might otherwise consider it to be.  He also compares the masqueraders to living dreams via metaphor.  The personification...

As for figurative language, Poe makes an allusion to the Victor Hugo play, Hernani, first performed in 1830, in order to enrich his own imagery by relying on the splendor associated with another famous production.  Poe also personifies the clock, giving it a voice, and thus making it seem more powerful and symbolic than we might otherwise consider it to be.  He also compares the masqueraders to living dreams via metaphor.  The personification of the clock continues when the narrator describes its chimes as dying.

In terms of imagery, the descriptions of the masqueraders allows us to visualize what the scene must look like.  They are all "glare and glitter and piquancy and phantasm" in one, "writhing" in and out of the various colored rooms, taking their own hue from the colors around them.  The description of the "ebony clock which stands in the hall of the velvet" is visual imagery as well, and auditory imagery is used to describe its chimes ringing out in the dead-silence that envelops the courtiers when the hour arrives: "all is still, and all is silent save the voice of the clock."  We get further visual imagery from the description of the light in the room where the clock is located: the ruddy light pours in through "blood-coloured panes," seeming to soak the whole room.

Poe repeats words such as "dreams" and well as descriptors that signal something strange (like "grotesque" and "disgust") to emphasize that what is happening in these rooms is simply not natural, and thus the mood is one of both anticipation and dread of the outcome.  These feelings are furthered by the repetition of words that mean black -- sable, ebony -- and red -- blood, ruddy -- making the mood that much more deadly and dreadful.