What are some literary devices used in "To the Virgins, Make Much of Time"?

As mentioned above, the theme of this poem is "Carpe diem," or "seize the day." It strongly advises young women ("virgins") to enjoy life now. They should enjoy life today because they never know what will happen: they may die, and if they don't, they will become old and undesirable.

Literary devices used in the poem include metaphor. A metaphor is a comparison that does not use the words "like" or "as." A metaphor in poetry often compares  a concrete image that we  can see, touch, hear, taste, or smell to an abstract concept.

In this poem, the sun becomes a metaphor for time. A human lifetime is thus compared to a single day. A life, like the sun rises (is born), reaches its zenith, and sets. The setting sun is a metaphor for death.

Further, the sun itself is compared to a lamp, another metaphor. Herrick calls the sun "the glorious lamp of heaven." 

Herrick also uses alliteration, which is using the same consonant more than once at the beginning of words in close proximity to each other. In this poem, we read:

And while ye may, go marry.

"May" and "marry" are alliterative, which draws attention to them. There's also a suggestion of a pun in these words: "may" means "can" or "be able to," but it also is the name of a month associated with springtime, the blossoming of plants, and youth. "Marry," likewise, seems to mean "merry" or happy, but also sounds like and is spelled as "marry," meaning to wed. One way to seize the day is to marry while you can, in other words, while still young and desirable. 

The first line of the poem advises the hearer to "Gather ye rose-buds while ye may" (line 1).  Here, the narrator assumes a youthful audience, and he cautions her to symbolically collect lovers (rose-buds) now.  Time passes quickly, the narrator says, and, soon, this lover will be growing old too. 

The narrator uses a metaphor to compare the sun to a celestial lamp (5), personifying the sun as well by calling it a "he" and comparing his course across the sky during the day to a "race," another metaphor (6, 7).  Here, the day is being used as a symbol of a human lifespan: sunrise is birth, sunset is death.  Youth passes quickly, and, before we know it, we are near the end of our "day," and we grow old and die.

The narrator says, then, that youth is best, that "blood [is] warmer"; this is figurative as well because our blood isn't actually any hotter when we are younger.  He is referring to passion (substituting warmth by using a device known as metonymy); we are more passionate when we are young.  Then, as our passion fades, we age, and things get worse and worse for us.

Ultimately, there is quite a bit of figurative language in the poem: symbols, metaphors, personification, and metonymy. 

A symbol is something that has both literal and figurative meaning. In the first line of the poem, the speaker advises his audience to "Gather ye rose-buds while ye may," a line that seems to convey both kinds of meaning.

First, on a literal level, the speaker is saying to enjoy the beautiful weather of spring; there are new flowers blooming, and those flowers will die soon enough, so we ought to seize the day. However, on a figurative level, the speaker seems to be suggesting that his audience enjoy their youth and make the most of their vitality and beauty, collecting lovers now before too much time passes and they grow too old to do so. After all, "Time is still a-flying!" Therefore, the rose-buds are a symbol of romantic conquests, of lovers, as even the title suggests that the intended audience is composed of virgins.

In the final stanza, the speaker advises these virgins not to be "coy" or teasingly flirtatious or standoffish but, rather, to take advantage of their "warm" blood, the result of the "best" age (youth, of course), because, as time passes, "worse" and "worst / Times" eventually come to "succeed the former." It is possible that the speaker is addressing one particular young maiden with whom he would like to sleep with, or perhaps he is just admonishing all young maidens not to squander their youth and beauty and to collect some rose-buds and lovers while they still can.

The controlling metaphor of Robert Herrick's "To the Virgins, to Make Much of Time" is that of life being like a rosebud.  The speaker tells the young virgins to "gather ye rosebuds while ye may," urging them to understand the ephemeral nature of youth.  Like the rosebud, the young women have only a short time in which they are beautiful and "when youth and blood are warmer." 

Set in contrast to the workings of the universe, the youthful life of the young women is short, indeed.  The sun "will his race to run" and will be setting; that is, life ends quickly.  The rhyming of "first" with "worst" in the third stanza suggests this inevitability.  So, in the last stanza, the speaker urges again the young, warm-blooded women to marry

For having lost but once your prime
You may forever tarry.

Opportunities to enjoy one's youth and beauty and passion are ephemeral when set against the span of nature; if the young virgins do not take advantage of these opportunities, they may lose their chances for happiness and fulfillment. For, like the rose, they will lose their beauty and youthfulness.

To me, the theme of this poem can be captured in two words: carpe diem.  This means "seize the day" in Latin.  The main theme of this poem is that life is short and that, because life is short, you should take what you can get as soon as you can get it.

The poem is supposed to be aimed at young women.  It is telling them that they are now in the primes of their lives.  It is saying that when you are in the prime of life, you are about to head downhill towards death.  So you might as well live while you can.

What metaphors does the poet use in "To the Virgins, to Make Much of Time"?

A metaphor is a comparison that does not use the words like or as. In Herrick's poem, love is likened to rosebuds or flowers, sweet flowers that will not last long. This metaphor emphasizes that life and love are short and fleeting. If one doesn't pick and enjoy the flowers now, they will be gone.

The sun is compared to a lamp. A day is likened to a race that will soon be over. A lamp goes out and a race ends, so these metaphors too add urgency to the idea that one should live life fully while it is still possible.

This is a classic example of a "carpe diem" poem. Carpe diem means seize the day. These poems are driven by the idea that we will soon grow old and die, so we should seize our joys while we can.

The primary metaphor is "Gather ye rosebuds while ye may." Rosebuds are youth and beauty. This is the theme of the poem, which is "carpe diem" or "seize the day." We only have one life, and one youth. It must be enjoyed while it lasts.

Just as a reminder: a metaphor is "a figure of speech in which an expression is used to refer to something that it does not literally denote in order to suggest a similarity. "

What figurative language is used in "To the Virgins, To Make Much of Time"?

The link below will give you greater detail on the multitudes of figures of speech, but in this poem, the most obvious include the allusion to Old Time (Father Time) and the Lamp of Heaven (the sun) which uses hyperbole by overexaggerating the speed at which time passes for these virgins.  The speaker tells them that time is flying and by the day they are getting older and uglier, so while they still can, stop being coy and get married as this is their primary duty as a young lady in this time period.  Otherwise, you will forever be an unmarried spinster which is never the desire of any young woman.