Which of these excerpts from poems by emily dickinson uses irony?

my cocoon tightens, colors tease,
i'm feeling for the air;
a dim capacity for wings
degrades the dress i wear.

could she have guessed that it would be;
could but a crier of the glee
have climbed the distant hill;
had not the bliss so slow a pace, —
who knows but this surrendered face
were undefeated still?

one dignity delays for all,
one mitred afternoon.
none can avoid this purple,
none evade this crown.

there's a certain slant of light,
on winter afternoons,
that oppresses, like the weight
of cathedral tunes.

.heavenly hurt it gives us;
we can find no scar,
but internal difference
where the meanings are.

exultation is the going
of an inland soul to sea, —
past the houses, past the headlands,
into deep eternity!

I would contend that excerpt no. 4 uses irony ("There's a certain slant of light / On winter afternoons / That oppresses, like the weight / Of cathedral tunes").

Explanation: Just to elaborate a little on the answer, it can be added that irony is a sharp and concealed, or subtle, mockery. The speaker is here comparing the oppressing feeling caused by the slant of light on winter afternoons to the oppressing feeling caused, in her opinion, by the religious tunes that are played in cathedrals. Obviously tunes do not weigh in the literal meaning of the word, but by using the words in this fashion she sparks the reader's interest and attention, and "compels" him/her to think further, use his/her imagination, and read between the lines in order to understand the underlying messages or ideas.          

a

explanation:

hopefully this will you you're welcome