Charlotte didn’t know that Araminta fancied Scipio, and the other way round as well. She didn’t know that Araminta knew by whom Sarah was pregnant and under what conditions. She didn’t know the whispered conversations that the two sisters had under the eves nightly, or as often as they could manage it, as Sarah stitched away on quilts and Araminta pieced together clothing for Charlotte’s children after the models in the London and Paris pictorial magazines. (Araminta once copied the dress of a visiting lady from New York, merely from the glimpses captured while serving her tea and waiting on table at breakfast and luncheon.)
She didn’t know that Scipio had had harsh words with his sweetheart about what might be done about Sarah’s situation, if not her condition then her condition of life.
She didn’t know that Araminta looked out the garret window at the North Star.
E. P. Beaumont 
I really like the use of ‘She didn’t know..’, repeated. Perfect six.
The repetition works really well here, driving home the point how – what? Out of touch? Self absorbed? Ignorant? Charlotte is.
So many things for her to discover! And, like Elin, I’m also wondering why she is so oblivious. Intriguing six.
Charlotte’s ignorance is the result of careful work on the part of Araminta, Sarah, and Scipio, reinforced by the all-important notion that slaves were not quite up to human standard. The detail about Araminta reproducing the New York visitor’s dress, from no more information than what she saw at tea, hints at the formidable intelligence behind the mask of the servitor.
Yes it was clear why she knew so little and yes Araminta’s talent is obvious. I believe it’s the case with many slaved or enslaved that intelligence talent and skill exist, if only for the chance or opportunity to bring it forth
How heartbreaking that she has to hide her intellect and talent. Tragic.
A very telling except about the realities when one group sees another at “not human.”
When I began work on this story in 2009, I had been reading the novels of George Eliot, who makes splendid use of an analytical and detached third person. Here, I realized that I had to do the same, because Charlotte’s point of view excludes so much. Literally, looking through Charlotte’s eyes, Araminta is only a pair of hands. As soon as I stepped out of Charlotte’s head and spoke of what she did not know, I had the sensation of soaring; point-of-view is like camera-work in film. One has many, many choices, and each choice reveals different layers.
This has a strangely haunting feel to it, I really like it. Especially the last line.