Since a coffin can directly represent a loss of “life”, Emily tried to make use of that sense of loneliness and isolation (yet devoid of a feeling of terror), which can be found in a coffin, to denote a thing worse than death — a loss of “mind”, as opposed to a loss of “life”. In fact, that’s just the beginning of Emily’s irony, which is, burying someone that merely lost “herself (or himself)” instead of her (or his) “life”. The point is that in Emily’s mind, it was even worse than death to lose one’s own “Self’.
The first imagery showing up and running through the whole poem is the “Mourners”. In common sense, they were supposed to sob or wail over the lost person; while on the contrary, there were no sounds of sadness at all in the funeral, which is quite ironic. The only sound that the poem was trying to convey is their stupid march — treading, treading — and their so-called service — beating, beating, resembling an army of cumbersome robots in their “Boots of Lead” disposing a bin of trashes or nastily, corpses.
Weirdly enough, no mourning attire, no face, no interaction (for example, bestowing a rose on the dead, or whispering muffled with one another about the dead), and even no slightest feeling are described, at least for the sake of the dead person; instead, all in all is merely a simple statement of a routine procedure (arriving — taking a seat — waiting for the “Bell” ringing — then burying the coffin), so as to give the poem, in its least sense, the tone of a funeral procession. Yes, ironically, the least important thing seemed to be the dead guy; while the formality of the process was what only mattered.
In pursuit of consistency, Emily also used a ballad meter style, of which the strong rhythmic tone could exactly cater to the marching sound and play as similar to a dirge, and the simplicity sensed in this meter could echo with that of the funeral. In addition, this simple rhythm had been also achieved by the repetition of the same words — “treading and treading”, “beating, beating” and “dropped down, down”, where the sense of motion had been created for readers to feel by themselves and been stressed by alliteration as well.
However, on the other hand, the “simplicity”, both in the sense of the funeral and the “Mourners”, made a sharp contrast with the poet’s relatively complicated “mind”. And ironically, the only thing that was very likely to satirise that stupid “simplicity” had gone mad or even been lost, which is why Emily felt a Funeral in her “Brain”. Besides the visual imagery of “Mourners”, the sound of a “Bell” is another auditory one and its tolling was meant to signal the end of the funeral, which is, in fact, an echo to the imagery of “Mourners”.
In the fourth Stanza, Emily referred “being” to “an ear” — partly in that the living “Mourners”, just like the lifeless robots without the ability of independent thinking, was awaiting the next-step instructions, and apart from a heart, a brain created to sense feelings and thinking, an ear was the only organ they needed to simply absorb orders to proceed the funeral; partly in that hearing a sound can be a sign of “being” and is privileged to “the being”, both of which she was no longer in possession, and this in part explains why “Silence” and she belonged to some strange Race.
And “wrecked”, “solitary” were the only feelings that she had been having since being part of this “Race”. Apparently, the “Mourners” are a metaphor for all the people in her life that once mattered and since they were of the same race, they talked and acted in the same way that unfortunately she would never approve of and would do her best to satirize by despising them with a pen. She thought that staying reclusive could help maintain her superiority over the stir of the society, but is this really the case?
At first, they began their treading and gradually, their noise started to make sense and affect her in some way. “That Sense was breaking through — ”indicates that she had a momentary impression that her sense (or her mind) was escaping and continued to go away as the dash implies. The treading evolved into the beating, which confused her and finally managed to numb her mind. For them, the treading and the beating would never be enough for such a complicated and mature mind; thus, they planned to beat it down, put it into a coffin and bury it; and before all that happened, they tortured it again and again, as “with the same Boots of Lead, again” implies. When the mind could no longer bear the torture, it came to an end with the “Bell” tolling. Finally, finally it surrendered and was determined to be estranged from the outside world and stay lonely “in her coffin” by stopping communicating with those “ears”, but the torment went on. Everything seemed fine until “a Plank in Reason, broke” and she began to descend — madness, madness, madness. What could have been more awful if there was a hole on her mind?
But what’s worse, even though she kept dropping, experiencing all types of mental disorders, there was no demise and there would never be one, which means that she had to be kept under torture and pain. This is the most horrible thing, worse than death. The ironic part lies in that the pain she had been through was actually brought about by her own self. She built herself a coffin to avoid harm or obstacles in her way and keep her mind intact, which unavoidably led to her emptiness or even depression. There is a turn in rhyme in the last stanza — “And I dropped down, and down- /And hit a World, at every plunge, /And finished knowing then“.
The use of the slant rhyme wakes us up out of the boredom of the marching sound, and this turn also marks the waking up of Emily when she realized that something was wrong with her mind. This blink of realization was actually caused by the speed of the dropping, as Emily used “plunge” to depict her situation. Before the “realization”, she was by no means self-conscious of what was going on and the fact that everything taking place in her brain was all made up by her own self as a way to flee away from the outside world.
However, ironically, no matter how hard she tried to bury her mind, she was just fleeing away to another state — mad, solitary, wrecked and worst of all, hopeless. After the “realization”, she was disillusioned, which is actually even more tragic, because there was no way to bury her mind but merely transforming its state into abnormality. Instead of a period, Emily used a dash to end the poem, which tells the readers that there would be no end to this hopeless process but an eternal struggle with self-consciousness — an eternal inner torture.