In Chapter 4, Jacobs describes her uncle Benjamin's run-in with a white man from South Carolina after Benjamin has escaped to Baltimore. Jacobs uses the metaphor of a "mystic clock" to describe the white man's conscience:
[Benjamin's] first impulse was to run; but his legs trembled so that he could not stir. He turned to confront his antagonist, and behold, there stood his old master’s next door neighbor! He thought it was all over with him now; but it proved otherwise. That man was a miracle. He possessed a goodly number of slaves, and yet was not quite deaf to that mystic clock, whose ticking is rarely heard in the slaveholder’s breast.
Benjamin has already run away and been caught once. He is terrified that the neighbor of his former enslaver is going to recognize him and bring him back to South Carolina. This man is an enslaver himself, so it stands to reason that he would see Benjamin as his neighbor's "property." Benjamin is shocked to find that the white man does recognize him, but he allows Benjamin to go free. By describing the man's conscience as a "mystic clock," Jacobs suggests that his morality comes from an internal sensor marking the time until slavery will die out or blow up.
It was fairly common by the mid-19th century for white people to believe that slavery was an immoral institution and yet to enslave people anyway. Even white people whose wealth was built on slavery felt uncomfortable with it. Many of them believed that slavery would have to go eventually, but they hoped not to deal with its end themselves. In 1788, one man at the Massachusetts convention to ratify the United States Constitution claimed that if slavery did not die by an "apoplexy" (a quick death, like a stroke), it would surely die by "consumption" (a slow and wasting death, often caused by tuberculosis). The Black abolitionist Frederick Douglass compared slavery to a slumbering volcano, waiting to erupt. Around the same time as Jacobs was writing, the white novelist Herman Melville foregrounded Douglass's comparison in his novella Benito Cereno. The mystic clock represents the idea of slavery as a ticking time bomb. People knew that something like the Civil War was coming on account of slavery. The neighbor who spots Benjamin in Baltimore has not yet divested from the institution by ceasing to enslave people, but he does not want to entangle himself in it any further by turning Benjamin in.
In Chapter 14, Linda uses a metaphor comparing the "genealogies of slavery" to "tangled skeins:"
When my baby was about to be christened, the former mistress of my father stepped up to me, and proposed to give it her Christian name. To this I added the surname of my father, who had himself no legal right to it; for my grandfather on the paternal side was a white gentleman. What tangled skeins are the genealogies of slavery! I loved my father; but it mortified me to be obliged to bestow his name on my children.
Skeins are twisted balls of thread or yarn, from which clothing or other textiles can be knitted, woven, or sewn. Skeins can easily become knotted or tangled, either with themselves or with other skeins. The metaphor suggests that under the institution of slavery, families are tied up in one another. Trying to trace a line back through her own family inevitably takes Linda to the white families who have legally owned or even fathered her family members. As much as she might wish to, it is impossible to disentangle her "own" family from white enslavers.
This difficulty is written into the laws propping up the institution of slavery. Legally, slavery was inherited through the mother's side. This law was called partus sequitur ventrem, or "offspring follows the belly." This meant that white men could have children with enslaved women through sex that was, more often than not, non-consensual, and these children would also be legally enslaved. Linda's father had no right to his own father's name because legally he would have followed the condition of his mother into slavery. The law actually incentivized sexual assault, giving enslavers a way to increase their wealth by increasing the number of people they enslaved. In addition to the trauma enslaved women experienced as a direct result, entire families became "tangled skeins," so that familial bonds were rarely uncomplicated. Many people's very existence depended on the fact that an enslaver had sexually assaulted an enslaved woman. Linda's daughter's name documents the horrifying ways their family tree has been complicated and stained by slavery. It is difficult for the reader at times to keep track of how everyone in the narrative is related to one another, and this metaphor makes clear that this is because of slavery. Slavery is not a conflict with white Americans on one side and Black Americans on the other. Instead, it is a snarl in the yarn that makes up the entire country.
In Chapter 34, Linda gets a letter from Emily Flint, her former enslaver who could still legally kidnap her and bring her back to South Carolina. Dr. Flint also shows up in New York, and Jacobs uses a metaphor to compare enslavers to snakes:
But when summer came, the old feeling of insecurity haunted me. It was necessary for me to take little Mary out daily, for exercise and fresh air, and the city was swarming with Southerners, some of whom might recognize me. Hot weather brings out snakes and slaveholders, and I like one class of the venomous creatures as little as I do the other. What a comfort it is, to be free to say so!
The comparison begins as a simile: she claims to like snakes as little as enslavers (or "slaveholders" as she calls them). However, she ventures a more direct metaphor when she calls both snakes and enslavers "venomous." She notes that this comparison is daring, and that she likes being free to make it. Linda has a long-established fear and hatred of snakes, which she has encountered on her way to escape. They seem to her like an uncomplicated symbol of evil. Not only do they attack her, but they are also largely interpreted as a biblical symbol for sin and the devil. In the Book of Genesis, a serpent tricks Eve into eating the fruit of the tree of the knowledge of good and evil. This event is what instigates the fall of man: Adam and Eve are expelled from Paradise, and humans become mortal. By comparing enslavers to snakes, Linda is emphasizing the idea that enslavers are deceitful, malicious, and responsible for much of humanity's suffering. Especially now that the Fugitive Slave Act means that Emily Flint might sneak up on her and kidnap her out of any free state at any time, Linda has reason to see enslavers as serpents threatening the sanctity of her own Paradise. On the other hand, the metaphor also taunts enslavers. Linda has endured snakebites before. If enslavers and snakes are equally venomous, she is confident that she can survive the enslavers' bite as well.
The metaphor also reveals how freedom allows Harriet Jacobs to begin practicing the art of writing. "What a comfort it is," she exclaims, to be able to compare enslavers to snakes. She is relieved to speak her mind, but she also seems to take pleasure in the freedom to use figurative language. Jacobs's memoir is more than a simple catalog of the events of her life. It is also a rich literary work. She knew this and was protective of it, refusing to allow Harriet Beecher Stowe to publish sections of it in Uncle Tom's Cabin. This passage hints at Jacobs's self-image as a literary artist.
