"Hands" by Robinson Jeffers primarily offers visual imagery as the prominent literary device, such as 'brown shy quiet people." Nonetheless, Jeffers does employ the trope of figurative speech, which is speech that is not meant to be taken literally but that twists the literal meaning to produce a meaning that exceeds the individual words, e.g., he's the top brass. Some figures of speech Jeffers employs are simile, metaphor and personification.
Simile is present in "Signs-manual are now like a sealed message." Simile compares two unlike things through the associating words like, as, or as though. In this case, "Signs-manual" is associated with the term it's compared with ("sealed message") through the use of like.
Metaphor is present in "A multitude of hands in the twilight, a cloud of men’s palms." Metaphor compares two unlike things but does so, in contrast to simile, without using the associating words like, as, or as though. In this case, "hands in the twilight" is compared to "a cloud of men's palms," with no associating word to link them in the comparison.
Personification is present in "Saying: “Look: we also were human; we had hands, not paws" and in "In the beautiful country; enjoy her a season, her beauty." In the first, the "Signs-manual" of the preceding line are presented as having spoken words. This is personification, which is the assignment of human attributes or qualities to inanimate objects. In the second case, "the beautiful country" is personified through the assigned attributes of personhood ("her") and beauty ("her beauty").