This handwritten letter was composed during a period when Illinois allowed legal (but restricted) slavery.  Although slaves could not be sold, they could serve as indentured servants for lengthy terms and were often bought and sold illegally.  At the time, free black people were forced to carry papers referred to as "The Black Code."
The letter was written in 1834 by James Parkes of New Haven, Gallatin county, Illinois, to his brother Thomas Parkes in Franklin, Williamson county, Tennessee. We learn from the letter that Parkes has been attempting to have a sawmill constructed on the Little Wabash River but has been delayed by high water.
The correspondence is business-like in nature, including a post script touching on labor. In this postscript, James suggests to his brother that two slaves, Mat and Polly, be hired to assist him in either construction or operation of the mill if their owner will allow them to hire themselves out:
[P. S.] You can hire Mat and Polly if their owner will give them liberty to hire their own time with a pass. It must be with their own free will. I think it will answer every purpose—that is, if you don’t own them. Docker hires all his hands that way. Some indentures them. I don’t know that will answer.
The “pass” James refers to here is likely the aforementioned “Black Code”. This is an interesting view into slavery in a Northern state. The letter is in very good condition.
[Civil War, Union, Confederate] [Abolitionist, Slave, Slavery, Emancipation Proclamation, 13th Amendment, Civil Rights, Abraham Lincoln]