What are the literary devices used if the poem "Success is counted sweetest"?

In this poem the speaker states that success is most
valued by those who fail, just as victory in battle seems most precious to a soldier who
is defeated and dying. Dickinson uses an analogy to state her claim in the first
stanza:

To comprehend a
nectar

Requires sorest
need.

Here she compares a
thirsty person's appreciation of a drink to a loser's appreciation of victory, saying
that the thirstier you are the more you are going to value having that thirst quenched.
In the same way, those that suffer defeat will crave victory more than the
victors.

She goes on to use imagery very effectively in the
last stanza to seal her case:

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As he defeated - dying
-

On whose forbidden ear

The
distant strains of triumph

Burst agonised and
clear!

Dickinson thus creates
an image of a soldier dying on the battlefield (note the alliteration in "defeated -
dying" which emphasises the pity of the soldier's state) who is nevertheless able to
hear the victory chants and music of the opposition. He has just lost his life in vain
and thus, Dickinson argues, is able to comprehend the nature of success far more than
the victors.