Last year I traced the verse on Mary Hopkins alphabet and extract sampler of 1799 to a female slave. She was kidnapped aged 8 years and transported to America in 1771. There she was the property of Mr Wheatley of Boston, and there she wrote A Hymn to the Evening which was published in London in 1786. The authenticity of her authorship was attested by her owner and a number of governors and clergy. It is supposed that this was to prove that she was a sentient being. However, the name of the female slave is not given, nor do we know yet if she was ever emancipated. Here is the verse for you:
Fill'd with the praise of him who gives the light.
And draws the sable curtains of the night.
Let placid slumbers sooth each weary mind.
At morn to wake more heavenly more refin'd;
So shall the labours of the day begin.
More pure more guarded from the snares of sin.